阅读说明：本技术 激光焊接体及其制造方法 (Laser welded body and method for manufacturing same ) 是由 木原哲二 山本聪 于 2018-04-23 设计创作，主要内容包括：本发明提供一种激光焊接体,其能够在不经过复杂步骤的情况下被制造、且保持树脂构件中所含树脂的特性,即使在用激光束以高速扫描时也呈现出高焊接强度,并且能够以高生产效率制造。激光焊接体(10)包括第一树脂构件(1)和第二树脂构件(2),上述第一树脂构件(1)是激光照射的对象,包含热塑性树脂和苯胺黑硫酸盐、并且具有0.09～0.9的吸光度a<Sub>1</Sub>,上述第二树脂构件(2)包含与上述热塑性树脂相同或不同种类的热塑性树脂和激光束吸收剂、并具有3.0～15的吸光度a<Sub>2</Sub>,其中上述第一树脂构件(1)和上述第二树脂构件(2)在两个树脂构件叠合和/或对接的部位处被激光焊接。(The invention provides a laser welded body which can be manufactured without complicated steps and can maintain the characteristics of resin contained in a resin member even if the laser welded body is manufactured by complicated stepsHigh welding strength is exhibited also when scanned with a laser beam at high speed, and manufacturing can be performed with high production efficiency. A laser welded body (10) is provided with a first resin member (1) and a second resin member (2), wherein the first resin member (1) is the object of laser irradiation, contains a thermoplastic resin and nigrosine sulfate, and has an absorbance a of 0.09-0.9 1 The second resin member (2) contains a thermoplastic resin of the same or different type as the thermoplastic resin and a laser beam absorber, and has an absorbance a of 3.0 to 15 2 Wherein the first resin member (1) and the second resin member (2) are laser-welded at a portion where the two resin members are overlapped and/or butted.)

1. A laser welded body, comprising:

a first resin member which is an object to be irradiated with a laser beam, contains a thermoplastic resin and nigrosine sulfate, and has an absorbance a of 0.09 to 0.9₁And an

A second resin member comprising a thermoplastic resin of the same or different kind as the thermoplastic resin and a laser beam absorber, and having an absorbance a of 3.0 to 15₂，

Wherein the first resin member and the second resin member are laser welded at a portion where the two resin members are overlapped and/or butted.

2. The laser welded body according to claim 1, wherein the absorbance a is₂And the absorbance a₁Absorbance ratio of (a)₂/a₁Is 5 to 70.

3. Laser welded body according to claim 1 or 2, characterized in that the laser beam absorber is nigrosine sulfate and/or carbon black.

4. The laser welded body according to any one of claims 1 to 3, wherein the nigrosine sulfate has a sulfate ion concentration of 0.3 to 5.0 mass%.

5. The laser welded body according to claim 3, wherein the carbon black has a primary particle diameter of 12 to 40nm and a particle diameter of 150 to 380m²Nitrogen adsorption specific surface area per gram.

6. The laser welded body according to any one of claims 1 to 5, wherein the thermoplastic resin is at least one selected from the group consisting of a polyamide resin, a polycarbonate resin, a polyphenylene sulfide resin, a polyethylene terephthalate resin, a polybutylene terephthalate resin, and a polypropylene resin.

7. The laser welded body according to any one of claims 1 to 6, wherein the first resin member and/or the second resin member contains a colorant containing anthraquinone.

8. The laser welded body as defined in claim 7, wherein said anthraquinone is an anthraquinone salt-forming dye.

9. The laser welded body as defined in claim 8, wherein said anthraquinone salt-forming dye is represented by A^-B⁺Or AB represents, A^-B⁺A in (A)^-Is an anion from anthraquinone, B⁺Is a cation derived from an organic ammonium compound, A in AB is a residue of anthraquinone, and B is a residue of an organic ammonium compound.

10. A method of manufacturing a laser welded body, comprising:

forming an opposing portion by overlapping and/or abutting a first resin member and a second resin member, wherein the first resin member includes a thermoplastic resin and nigrosine sulfate and has an absorbance a of 0.09 to 0.9₁The second resin member includes a thermoplastic resin of the same or different kind as the thermoplastic resin and a laser beam absorber, and has an absorbance a of 3.0 to 15₂(ii) a And

welding the first resin member and the second resin member by irradiating with a laser beam from one side of the first resin member to melt at least a part of the first resin member and the second resin member at the opposing portion.

11. The method of manufacturing a laser welded body according to claim 10, comprising irradiating with the laser beam at a scanning speed of 100 to 300 mm/sec.

Technical Field

The present invention relates to a laser welded body in which resin members having a specific absorbance are integrated with each other by laser welding.

Background

Lightweight thermoplastic resin products can be used as parts of vehicles such as automobiles and railways in the field of vehicles, and as structural parts in the field of electronic and electrical equipment, instead of metals. As a method for joining thermoplastic resin members, a laser welding method is known.

The conventional laser welding method is performed as shown in fig. 7. A laser-transmissive resin member 11 having laser beam transmissivity is used for one member. A laser beam absorbing resin member 12 having laser beam absorbability is used for the other member. By laminating and contacting these two resin members, the contact portion N is formed. The laser beam L is irradiated from the side of the laser transmissive resin member 11 toward the laser absorptive resin member 12 to the contact portion N. The laser beam L transmitted through the laser-transmissive resin member 11 is absorbed by the laser-absorbing resin member 12, and heat is generated therein. Heat is concentrated at the laser absorption site thereof to melt the laser light absorbing resin member 12, and then the laser light transmitting resin member 11 is melted, thereby fusing the two resin members. After cooling, the laser transmitting resin member 11 and the laser absorbing resin member 12 are welded at the contact portion N. A conventional laser welded body 13 was produced.

The laser welding method has the following advantages: welding of the resin members can be performed as long as the regions to be joined are locally irradiated with the laser beam; since heat release is locally generated, the thermal influence on the periphery other than the welding portion is small; no mechanical vibration is generated; welding of fine parts or resin members having a three-dimensional complex structure can be performed; the reproducibility is excellent; high air tightness can be kept; the bonding strength is high; the boundary line of the welding part is not obvious; no dust is generated.

According to the above welding method, the resin members can be welded tightly by firmly welding them together. It is also possible to achieve a joining strength equivalent to or higher than that of the existing method for joining resin members. Examples of existing methods for joining resin members are clamping using a jig (a bolt, a screw, a clip, or the like), bonding using an adhesive material, vibration welding, ultrasonic welding, or the like. According to the laser welding method, since there is little vibration and the thermal influence is minimized, labor saving, productivity improvement, production cost reduction, and the like can be achieved. Therefore, in, for example, the automobile industry, the electrical industry, or the electronic industry, the laser welding method is suitable for joining functional parts or electronic parts whose vibration or thermal influence should be avoided. The laser welding method can also be applied to joining resin members having complicated shapes.

As a technique related to the laser welding method, patent document 1 discloses a laser welding method. In this method, in order to weld two resin members, a laser-absorbing resin member to which carbon black that absorbs a laser beam is added is superimposed on a laser-transmitting resin member, and then a laser beam is irradiated thereto from the side of the above-described laser-transmitting resin member. In this case. The laser-transmissive resin member is essential. The welding of the above laser light transmissive resin member and the above laser light absorbing resin member depends only on the heat generation of the laser light absorbing resin member and melts because the laser light transmissive resin member is not exothermically melted by the laser beam irradiation. Therefore, the resin member cannot be welded to an excellent welding strength (tensile strength) for the following reasons: the amount of heat release is small relative to the energy of the irradiated laser beam; the heat efficiency is low; and the melting region in the laser transmissive resin member is narrow. Further, when a laser beam having a high output is irradiated to a resin member in order to achieve an excellent welding strength, a focal mark and a void are generated at a welding portion due to excessive heat release of the laser-absorbing resin member. Therefore, the weld strength is rather lower.

Patent document 2 discloses another laser welding method. In the method: butting joint flange portions formed in advance as joint wings for welding the laser light transmitting resin member and the laser light absorbing resin member, respectively; irradiating a laser beam from one side of a joining flange portion of the laser transmissive resin member to temporarily weld the two resin members; then, the joining flange portion is irradiated with a laser beam to perform main welding, so that the two resin members are integrated. In this method, as in the laser welding method disclosed in patent document 1, a laser-transmissive resin member is also necessary.

Patent document 3 discloses another laser welding method. In this method, thermoplastic resin members A and B are brought into contact with a heat dissipating material C having an infrared ray transmitting portion in the order of C/A/B, and then these resin members are irradiated with infrared rays from one side of the heat dissipating material C. According to this method, the thermoplastic members a and B can be made of the same thermoplastic resin. However, in this method, the heat release must be adjusted by using a specific heat sink material C. The heat sink material C is not a member for manufacturing a laser welding portion, and is also manufactured only for laser welding, so that the process in the laser welding method is complicated.

Disclosure of Invention

Technical problem to be solved by the invention

In japanese patent laid-open No. 2007-112127A, the inventors of the present invention proposed that a laser welded body having excellent strength be realized by laser welding a laser weak absorption resin member that adjusts the absorbance to a specific range by containing nigrosine as a laser beam absorber and a laser absorption resin member that contains, for example, nigrosine or nigrosine and carbon black as a laser beam absorber.

According to the above invention, the melting range (molten pool) can be expanded as compared with the conventional laser welding method, and a laser welded body having a more excellent tensile strength can be obtained. In addition, the above invention has the following features: under the laser beam irradiation conditions of low energy and low laser beam scanning speed, the growth of the molten pool expands, and the welding strength of the laser welded body increases. However, performing laser beam irradiation at high energy and high scanning speed makes it difficult to produce a laser welded body in which a greater number of resin members are high-intensity welded per unit time.

For example, in a production line of an automobile or a home appliance factory, improvement of production efficiency at a high production speed has become one of important issues. Therefore, there is a need in the industry for laser welded bodies made by the following laser welding process: a laser welding method capable of producing a laser welded body having excellent welding strength even if laser beam irradiation is performed at a high scanning speed; further, there is a highly practical laser welding method that can be introduced into a production line at low cost.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a laser welded body which can be manufactured without complicated steps and can maintain the properties of a resin contained in a resin member. It is also an object of the present invention to provide a laser welded body which exhibits high welding strength even when scanned with a laser beam at high speed and can be manufactured with high production efficiency, and a manufacturing method thereof.

Technical scheme for solving technical problem

The inventors of the present invention found the following: by employing a single resin member or a plurality of resin members, high thermal conductivity is imparted to the resin member, and the absorbance is adjusted to a specific value to transmit one portion of the laser beam while absorbing another portion thereof, whereby the melting phenomenon in the resin member caused by irradiation of the resin member with the laser beam is deepened to become large. Moreover, the melted portion rapidly expands in a wide range. As a result, a laser welded body in which resin members are more firmly joined can be obtained more quickly than in the conventional laser welding method.

A laser welded body of the present invention developed to achieve the above object includes a first resin member and a second resin member, wherein the first resin member is a target of laser irradiation, includes a thermoplastic resin and nigrosine sulfate, and has an absorbance a of 0.09 to 0.9₁The second resin member contains a thermoplastic resin of the same or different kind as the thermoplastic resin and a laser beam absorber, and has an absorbance a of 3.0 to 15₂Wherein the first resin member and the second resin member are laser-welded at a welding portion where the two resin members are overlapped and/or butted.

In the laser welded body, the absorbance "a" is₂With a of absorbance₁Absorbance ratio of (a)₂/a₁Can be 5 to 70.

In the laser welded body, the laser beam absorber is preferably nigrosine sulfate and/or carbon black.

In the laser welded body, the sulfate ion concentration of the nigrosine sulfate is preferably 0.3 to 5.0 mass%.

In the laser welded body, the carbon black preferably has a primary particle diameter of 12 to 40nm and a particle diameter of 150 to 380m²Nitrogen adsorption specific surface area per gram.

In the laser welded body, the thermoplastic resin may be at least one selected from the group consisting of a polyamide resin, a polycarbonate resin, a polyphenylene sulfide resin, a polyethylene terephthalate resin, a polybutylene terephthalate resin, and a polypropylene resin.

In the laser welded body, the first resin member and/or the second resin member may contain a colorant containing anthraquinone.

In the laser welded body, the anthraquinone is preferably an anthraquinone salt-forming dye.

In the laser welded body, the anthraquinone salt-forming dye may be represented by formula A^-B⁺(A^-Is an anion from anthraquinone, B⁺Is a cation derived from an organic ammonium compound) or AB (A is the residue of anthraquinone and B is the residue of an organic ammonium compound).

The method for manufacturing a laser welded body includes: the opposing portion is formed by overlapping and/or abutting a first resin member and a second resin member, wherein the first resin member contains a thermoplastic resin and nigrosine sulfate and has an absorbance a of 0.09 to 0.9₁The second resin member contains a thermoplastic resin of the same or different kind as the thermoplastic resin and a laser beam absorber, and has an absorbance a of 3.0 to 15₂(ii) a And welding the first resin member and the second resin member by irradiating with a laser beam from one side of the first resin member to melt at least a part of the first resin member and the second resin member at the opposing portion. In the above method of manufacturing a laser welded body, the first resin member and the second resin member may be in surface contact or line contact by inter-planar surfaces, curved surfaces, or a combination of inter-planar and curved surfaces. In the combination of these faces, there may be a gap of 0.01 to 0.5mm between the faces. As one of the features of the present invention, the present invention realizes welding of a member having a shape unsuitable for welding, which cannot be realized by usual heat conduction.

The method for manufacturing the laser welded body may include irradiating the laser beam at a scanning speed of 100 to 300 mm/sec. The above-described method of manufacturing a laser welded body is suitable for welding at a high scanning speed, thereby providing high work efficiency.

Effects of the invention

According to the laser welded body of the present invention, the laser weakly absorbent resin member and the laser absorbing resin member having both the laser beam transmitting property and the laser beam absorbing property are laser-welded without the laser transmitting resin member. Therefore, the laser weakly absorbent resin member and the laser-absorbent resin member after being superposed and butted generate heat together by incidence of the laser beam. The two resin members are welded together to exhibit high strength.

In the laser welded body of the present invention, since the laser weakly absorbent resin member contains nigrosine sulfate as a laser beam absorber, the laser weakly absorbent resin member exhibits a decrease in crystallization temperature, high fluidity and high melting property as compared with a resin member containing nigrosine hydrochloride. Therefore, compared to a laser welded body using a resin member containing nigrosine hydrochloride as a laser beam absorber, the laser welded body can be manufactured with high production efficiency by laser beam irradiation performed at a high scanning speed.

The laser weakly absorbent resin member in the above laser welded body rapidly generates heat and is thermally fused by receiving a laser beam. The melt of the laser weak absorption resin member is rich in fluidity. Therefore, even if a gap is formed between the stacked and/or butted laser weakly absorbent resin members, the gap can be closed by forming a wide range of melt pool (entire three-dimensional shape of the melt), and the laser welded body can exhibit high welding strength.

According to the laser welded body, since at least the laser weakly absorbent resin member contains nigrosine sulfate, a weld pool generated at the time of laser beam irradiation becomes large and grows without losing the original characteristics of the thermoplastic contained in the resin member. The laser welded body has high welding strength and small changes in the welding strength and appearance. Unlike a conventional laser welded body using a laser-transmissive resin member and a laser-absorptive resin member, no focal mark or void due to excessive energy is formed at the melting portion of the laser welded body.

According to the above-described method of manufacturing a laser-welded body, the laser-welded body having two resin members firmly welded therebetween can be simply manufactured for the following reasons: the first resin member to be irradiated with the laser light exhibits weak laser light absorption, i.e., has an absorbance a of 0.09 to 0.9₁Thus absorbing a part of the laser beam while transmittingAnother part thereof. Therefore, not only has higher absorbance a₂And the first resin member is also exothermically melted by irradiating the laser beam.

Drawings

FIG. 1 is a perspective view showing a manufacturing process of a laser welded body to which the present invention is applied and a partial schematic sectional view taken along line A-A.

FIG. 2 is a schematic cross-sectional view showing a manufacturing process of another laser welded body to which the present invention is applied.

FIG. 3 is a schematic cross-sectional view showing a manufacturing process of another laser welded body to which the present invention is applied.

FIG. 4 is a perspective view showing a scene of manufacturing another laser welded body to which the present invention is applied.

FIG. 5 is a cross-sectional enlarged photograph showing laser welded bodies of examples 2-1 and 2-2 to which the present invention was applied.

FIG. 6 is a perspective view and a partially enlarged sectional view showing a manufacturing method of a laser welded body to which examples 4-1 and 4-2 of the present invention are applied.

Fig. 7 is a perspective view showing a conventional method for manufacturing a laser welded body to which the present invention is not applied.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail, but the scope of the present invention is not limited to these embodiments. In the present specification, "to" means a range including an upper limit value and a lower limit value.

In the laser welded body of the present invention, at least the first resin member is a laser weak absorption resin member containing nigrosine sulfate and having both laser beam transmissivity and laser beam absorption. The second resin member is a laser beam absorbing resin member containing a laser beam absorber and having laser beam absorbability. The laser weakly absorbent resin member and the laser-absorbent resin member in the laser welded body generate heat, melt, and solidify by absorbing at least a part of the incident laser beam, thereby exhibiting high strength by welding. The laser weak absorption resin member and the laser absorption resin member may be flat plate-like or single layer film-like members, or may be single or plural members each bent or folded into a roll, a cylinder, a prism, or a box shape. The two resin members may be in contact with each other at the portions to be welded in the two resin members, or may have a gap therebetween. When the two resin members are brought into contact with each other, the portions to be welded are preferably surface-contacted, and may be between planes, between curved surfaces, or a combination of planes and curved surfaces.

A perspective view showing a manufacturing view of the laser welded body of the present invention is shown in fig. 1(a), and a partially schematic cross-sectional view taken along line a-a is shown in fig. 1 (b). The laser welded body 10 is an integral body in which a plurality of resin members are integrally formed by laser welding and joining. In the laser welded body 10, a laser weakly-absorbent resin member 1 as a first resin member located on the upper side and a laser-absorbent resin member 2 as a second resin member located on the lower side are offset-superposed so as to be superposed and brought into contact with each other in such a manner as to form a step. The laser weak absorption resin member 1 is a laser irradiation target. The laser weak absorption resin member 1 and the laser absorption resin member 2 are laser-welded at the overlapped interface portion. The contact portion N is an interface where the two resin members 1 and 2 contact each other to form an opposing portion. The laser welded body 10 has a welded portion M at the contact portion N. The welding portion M expands to join the laser weakly absorbent resin member 1 and the laser-absorbent resin member 2. The weld M is formed by cooling and solidifying a part of the two resin members melted by the incident laser beam L.

Both the resin members 1 and 2 are flat rectangular plate-shaped with a uniform thickness. The laser weak absorption resin member 1 contains nigrosine sulfate as a laser beam absorber and a thermoplastic resin. Thereby, the laser weak absorption resin member 1 absorbs a part of the laser beam L and transmits another part thereof. The laser light absorbing resin member 2 contains a thermoplastic resin, preferably nigrosine sulfate as a laser beam absorber, and absorbs the laser beam L transmitted through the laser light weakly absorbing resin member 1. The laser weakly absorbent resin member 1 as an object to be irradiated with the laser beam is located on the irradiation side of the laser beam L. The irradiation of the laser beam L is performed at an approximately perpendicular angle with respect to the irradiation surface of the laser weak absorption resin member 1. The laser beam L scans the irradiation surface in the X direction along a straight line. In the laser welded body 10, the two resin members 1 and 2 are integrally formed by welding at the contact portion N along a straight line.

The absorbance a of the laser beam having a wavelength range of 940nm outputted from the semiconductor laser by the laser weakly absorbent resin member 1₁Preferably 0.09 to 0.9, more preferably 0.1 to 0.7, and still more preferably 0.1 to 0.5. The absorbance a of the laser-absorbing resin member 2 with respect to the same laser beam₂Preferably 3.0 to 15, more preferably 3.0 to 13, and further preferably 5.0 to 12. When the two resin members 1,2 are laminated, a sufficient amount of energy needs to be applied to the two resin members 1,2 to generate the thermal fusion at the lamination interface, i.e., the contact portion N, by irradiation with the laser beam L. Particularly, when a laser welded body is manufactured efficiently, the scanning speed of the laser beam L is set to a high speed, for example, 100 to 300 mm/sec. In order to weld the two resin members 1,2 at a high scanning speed to obtain high strength, it is preferable to adjust the energy of the laser beam L to prevent the heat release amount of the resin members from being excessive or too small. Thereby preventing the seizing, scorching and voids on the two resin members 1, 2. Furthermore, heat conduction and radiation by the vertically grown melting portion at the contact portion N are also promoted. The resin members 1,2 are welded and more firmly joined. Due to the absorbance a₁And absorbance a₂The value of (b) is within the above range, the resin members 1,2 are joined with excellent strength even if the scanning speed of the laser beam L is high. Note that when the resin members 1 and 2 are stacked, all transmittance and absorbance are regarded as important.

Due to the absorbance a₁And absorbance a₂Within the above range, both the resin members 1,2 achieve the heat release characteristics necessary for the welding thereof and prevent excessive heat release due to the concentration of the energy of the incident laser beam L. Further, the laser weakly absorbent resin member 1, which is an object suitable for irradiation with a laser beam, and the laser-absorbent resin member 2, which is not directly irradiated with a laser beam, both generate heat sufficiently and melt. Further, even if the two resin members 1,2 have different thicknesses from each other, they are firmly welded, thereby enabling manufacture of a molded article having a resin composition havingA laser welded body 10 of complex shape. In the method of manufacturing the laser welded body, the laser weak absorption resin member 1 (first resin member) and the laser absorption resin member 2 (second resin member) may be in surface contact with each other by an inter-planar surface, an inter-curved surface, or a combination of an inter-planar surface and an inter-curved surface. In the combination of these faces, there may be a gap of 0.01 to 0.5mm between the faces.

Absorbance a₂And absorbance a₁The ratio of (A) to (B), i.e. the absorbance ratio a₂/a₁Preferably 5 to 70, more preferably 7 to 67, and still more preferably 10 to 67. Due to the absorbance a₂/a₁The ratio is within the above range, and the heat release amounts of the two resin members are not greatly different from each other. This is different from a laser welded body using a laser-absorbing resin member which excessively absorbs a laser beam and a laser-transmitting resin member which has laser beam transmissivity and generates insufficient heat by irradiation with a laser beam. According to the laser welded body 10 of the present invention, even if the laser beam L of low energy is used, it is possible to achieve a welding strength extremely higher than that of the conventional laser welded body.

Of the two resin members 1,2, at least the laser weakly absorbent resin member 1 has a lower crystallization temperature than the resin member containing no nigrosine sulfate because of the nigrosine sulfate. The laser weakly absorbent resin member 1 melted by the incident laser beam L exhibits rich fluidity. Therefore, even if there is a gap due to the surface roughness of the resin members 1,2, the laser weak absorption resin member 1 that is hot-melted can flow into the gap to fill the gap. As a result, the resin members 1,2 are firmly welded. The melt flow rate of the laser weak absorption resin member 1 (according to Japanese Industrial Standard K7210: 2014) is preferably 10 to 50g/10 min, more preferably 11 to 30g/10 min, still more preferably 12 to 20g/10 min, and still more preferably 13 to 18g/10 min.

The color tone of the resin members 1,2 is preferably a dark color, particularly a black color tone. For example, it is preferable that the thermoplastic resin compositions as the raw materials of the resin members 1 and 2 contain a colorant containing anthraquinone. The preferable amount of the colorant to be added can be suitably adjusted.

The method for manufacturing a laser welded body according to the present invention includes: laminating the laser weak absorption resin member 1 and the laser absorption resin member 2; irradiating the laser weak absorption resin member 1 with a laser beam from a side of the laser weak absorption resin member 1 to a surface thereof to weld at least a part of the two resin members 1, 2; thereby welding the two resin members together. According to the method for producing a laser welded body of the present invention, since the laser weakly absorbent resin member 1 containing nigrosine sulfate as a laser beam absorber and the laser absorbing resin member 2 preferably containing nigrosine sulfate as a laser beam absorber have low crystallization temperatures, a laser welded body having high strength can be efficiently obtained by scanning with a laser beam at a high scanning speed of, for example, 50 to 300 mm/sec, preferably 100 to 300 mm/sec. The manufacturing process of the laser welded body 10 includes, for example, the following steps a to D.

Step A: a laser weak absorption resin composition for molding into the laser weak absorption resin member 1 is prepared. The laser weak absorption resin composition contains a thermoplastic resin and nigrosine sulfate as a laser beam absorber, and may optionally contain a colorant and an additive. Adjusting the content of nigrosine sulfate so that the absorbance a is adjusted based on the inherent absorbance of the thermoplastic resin₁Within the range of 0.09 to 0.9. The laser weakly absorbent resin member 1 having, for example, a rectangular plate shape is molded by a molding machine. The laser weakly absorbent resin member 1 may be molded by the following steps: a step of powder-mixing a plurality of laser weak absorbing resin compositions comprising a thermoplastic resin, a laser beam absorber and optionally a colorant and an additive, and a step of preparing a master batch by extrusion-molding the laser weak absorbing resin composition. The laser weak absorption resin member 1 contains nigrosine sulfate as a laser beam absorber. In addition to these, the following laser beam absorber may be further contained therein as necessary.

As aniline black, a black azine-based condensation mixture, indicated by the Color Index (Color Index) as c.i. solvent black 5 and c.i. solvent black 7, is exemplified. Nigrosine is synthesized, for example, by dehydrating, condensing and oxidizing aniline, aniline hydrochloride, and nitrobenzene at a reaction temperature of 160 to 180 ℃ in the presence of ferric chloride. From the viewpoint of improving the fluidity of the thermoplastic resin, c.i. solvent black 5 is more preferable.

According to the nigrosine production reaction system using ferric chloride as a catalyst, nigrosine hydrochloride is produced because the reaction is carried out in the presence of ferric chloride and/or an excess of hydrochloride. The method for producing nigrosine sulfate from nigrosine hydrochloride is not limited as long as all chloride ions or the corresponding portions thereof are replaced with sulfate ions, and known reaction methods can be used. Further, nigrosine sulfate is not a water-soluble black dye belonging to c.i. acid black 2, but an oil-soluble black dye belonging to c.i. solvent black 5.

A method for preparing nigrosine sulfate specifically comprises, for example, dispersing nigrosine into dilute sulfuric acid and heating it moderately (for example, 50 to 90 ℃). In addition, nigrosine sulfate can also be produced, for example, by the following steps: a step of dispersing the condensation reaction liquid obtained by producing nigrosine in dilute sulfuric acid, and a step of heating the mixture appropriately (for example, at 50 to 90 ℃). In addition, nigrosine sulfate can be produced, for example, by the following steps: a step of dissolving nigrosine in concentrated sulfuric acid while maintaining the temperature of the reaction solution at a low temperature to prevent sulfonation, and a step of adding the resulting solution to a large amount of ice water to precipitate crystals.

The nigrosine sulfate has a sulfate ion concentration of 0.3 to 5.0 mass%, preferably 0.5 to 3.5 mass%, and thus the crystallization temperature of the thermoplastic resin is greatly reduced. Thereby, the laser welding process can be simply and stably performed. The sulfate ion concentration in nigrosine sulfate was measured by instrumental analysis using ion chromatography after extracting sulfate ions from a nigrosine sample. In the process for producing nigrosine sulfate, impurities, inorganic salts, and the like in the raw nigrosine sulfate are removed, and therefore, the insulation properties of nigrosine sulfate are improved. Therefore, the nigrosine sulfate is more suitable for a product material requiring insulation properties such as an electric component and an electronic component than a resin material containing carbon black.

The volume resistivity of nigrosine sulfate is preferably 1.0X 10⁹Omega cm or more, more preferably 5.0X 10⁹～7.0×10¹¹Omega. cm, more preferably 8.0X 10⁹～1.0×10¹¹Omega cm. Materials containing nigrosine sulfate exhibiting high volume resistivity are preferably used for parts requiring high insulation, such as electric parts and electronic parts. Therefore, nigrosine sulfate-containing materials can be widely used in industry. The volume resistivity of nigrosine sulfate was obtained as follows: weighing a certain amount of nigrosine sulfate to prepare a sample; applying a load of 200kgf to compact the test specimen; measuring the volume of the sample; the volume resistivity of the sample was measured with a digital ultra-high resistance/micro-current ammeter (manufactured by ADC Co., Ltd., trade name: 8340A).

The content of nigrosine sulfate in the laser weakly absorbent resin member 1 is 0.01 to 0.3 mass%, preferably 0.01 to 0.2 mass%. When the content is less than 0.01% by mass, the absorbance a₁Less than the above lower limit. As a result, the heat release amount of the laser weak absorption resin member 1 that absorbs a part of the energy of the laser beam is too small and the temperature rise is insufficient. The welding at the butt portion B and the contact portion N is insufficient, and thus the joining strength of the two resin members 1,2 is poor. When the content is more than 0.3% by mass, the absorbance a₁Above the upper limit. As a result, since the laser beam transmissivity of the laser light weak absorption resin member 1 as a laser irradiation object is significantly reduced, only the laser light weak absorption resin member 1 excessively absorbs energy to generate heat and melt. The two resin members 1,2 are not firmly welded, and thus high joining strength cannot be achieved. When the laser irradiation object located on the laser beam incident side excessively absorbs the energy of the laser beam, resin characteristics such as physical and chemical characteristics from the material thereof are easily lost.

And B: a laser-absorbing resin composition for molding into the laser-absorbing resin member 2 is prepared. The laser-absorbing resin composition contains a thermoplastic resin and nigrosine sulfate as a laser beam absorber and/or the following laser beam absorber. The laser light absorbing resin composition may further contain a colorant and an additive, as required. Adjusting the content of laser beam absorber such as nigrosine sulfate and carbon black based on the inherent absorbance of the thermoplastic resin to absorbLuminosity a₂Within the range of 3.0 to 15. The laser-absorbing resin member 2 having, for example, a rectangular plate shape is molded by a molding machine. The laser light absorbing resin member 2 may be molded by the following steps: a step of powder-mixing a plurality of laser-absorbing resin compositions comprising a thermoplastic resin, a laser beam absorber and optionally containing a colorant and an additive, and a step of preparing a master batch by extrusion-molding the laser-absorbing resin composition. The laser beam absorber content in the laser-absorbing resin member 2 is 0.1 to 5.0 mass%, preferably 0.3 to 3.0 mass%.

The laser beam absorber contained in the laser light absorbing resin member 2 may include aniline black, a mixture of aniline black and carbon black, phthalocyanine, naphthalocyanine, porphyrin, a cyanine-based compound, perylene, tetrarylene, an azo metal complex, an oxohydrocarbon derivative (for example, squarylium derivative, croconic acid derivative, etc.), an oxime metal complex, a dithiolene metal complex, a dithiol metal complex, an aminothiophenol metal complex, a naphthoquinone compound, a diimmonium dye, a benzodifuranone compound, carbon black, and the like, in addition to aniline black and a salt thereof (preferably, nigrosine sulfate).

Examples of the inorganic laser beam absorber include oxides, hydroxides, sulfides, sulfates, and phosphates of one or a combination of two or more metals selected from copper, bismuth, aluminum, zinc, silver, titanium, antimony, manganese, iron, nickel, chromium, barium, gallium, germanium, cesium, and tungsten. As a preferable inorganic laser beam absorber, a bismuth pigment (e.g., Bi) can be exemplified₂O₃、BiOCl、BiONO₃、Bi(NO₃)₃、Bi₂O₂CO₃BiOOH, BiOF, etc.), molybdate derivatives (e.g., molybdenum molybdate, zinc molybdate, ammonium molybdate, sodium molybdate, etc.), tungstate derivatives (e.g., zinc tungstate, ammonium tungstate, sodium tungstate, iron tungstate, cesium tungstate, etc.), tungsten oxides (e.g., Rb_0.33WO₃、Cs_0.20WO₃、Cs_0.33WO₃、Tl_0.33WO₃、K_0.33WO₃、Ba_0.33WO₃Etc.), nitrides (titanium nitride, zirconium nitride, etc.), copper hydroxide phosphate, and copper phosphate.

As for the carbon black, the production method thereof, the kind of raw materials thereof, and the like are not limited, and any conventionally known carbon black can be used. For example, any of furnace black, channel black, acetylene black, ketjen black, and the like can be used. Among them, furnace black is preferable from the viewpoint of coloring properties and cost. The primary particle size of the carbon black is suitably selected, and is preferably 12 to 60nm, more preferably 12 to 40nm, and still more preferably 12 to 22 nm. When the primary particle diameter of the carbon black is 12nm or more, the fluidity tends to increase. When the primary particle diameter is 60nm or less, the degree of jet-black of the molded article increases.

In general, a material having a thickness of less than 500m may be used²Carbon black having a nitrogen adsorption specific surface area per gram. Wherein the nitrogen adsorption specific surface area is preferably 50-400 m²(iv)/g, more preferably 120 to 380m²(ii) g, more preferably 150 to 350m²(ii) in terms of/g. The nitrogen adsorption specific surface area is less than 500m²At the time of/g, the fluidity of the resin composition for molding the laser-absorbing resin member 2 and the appearance of the laser-absorbing resin member 2 as a molded article tend to be excellent. The nitrogen adsorption specific surface area is measured according to Japanese Industrial Standard K6217, specifically K6217-2 (2001). The DBP (dibutyl phthalate) absorption of the carbon black is preferably less than 300cm³100g, particularly preferably 30 to 200cm³100g of the total weight. DBP (dibutyl phthalate) absorption value of less than 300cm³At a concentration of 100g, the resin composition is excellent in flowability and appearance of a molded article. The DBP (dibutyl phthalate) absorption value is measured according to Japanese Industrial Standard K6217, in particular K6217-4 (2017). The carbon black content in the laser-absorbing resin member 2 is 0.1 to 1.5 mass%, preferably 0.2 to 1.0 mass%. As a preferred laser beam absorber, nigrosine and a salt thereof (nigrosine sulfate), and/or carbon black (preferably having a primary particle diameter of 12 to 40nm and a particle diameter of 150 to 380 m) can be exemplified²Carbon black having a nitrogen adsorption specific surface area/g, more preferably a primary particle diameter of 12 to 22nm and a particle diameter of 150 to 330m²Carbon black per g of nitrogen adsorption specific surface area).

And C: the two resin members 1,2 are stacked and brought into contact with each other to form a contact portion N. At this time, the two resin members 1,2 can be fixed by clamping them with a jig and then pressing them. An antireflection member such as a glass plate or an antireflection film, or a transmission member such as a glass plate which does not shield and attenuate the laser beam L may be used. The above-described antireflection member and transmission member may be placed on the laser light entrance surface of the first laser light weak absorption resin member 1 as the laser beam irradiation object. The laser beam L is incident on its surface.

Step D: the laser beam L set to a specific condition is irradiated from the side of the laser weak absorption resin member 1 while moving in the X direction to reach the laser absorption resin member 2 via the contact portion N. First, the laser beam L is incident on the laser weak absorption resin member 1. A part of the laser beam L transmits through the weak laser-absorbing resin member 1. Another part thereof is absorbed into the laser light weak absorption resin member 1 and causes it to generate heat. The portion of the laser weak absorption resin member 1 that has absorbed the laser beam L generates heat. The laser beam L transmitted through the laser weak absorption resin member 1 is incident on the laser absorption resin member 2 through the contact portion N and absorbed. In the laser-absorbing resin member 2, the contact portion N is melted first. The melting grows toward the face opposite to the face having received the laser beam L. As a result, the melt pool is formed as part of both resin members 1,2 in such a manner that the liquid resin in a molten state accumulates.

When both the resin members 1,2 contain nigrosine sulfate, a low crystallization temperature and high fluidity are exhibited. Both of the resin members 1,2 are melted rapidly by incidence of the laser beam L, thereby forming a melt pool. Therefore, the scanning speed of the laser beam L is much higher than that of the conventional laser welding method. The laser welded body 10 is manufactured with extremely high production efficiency.

The heat of the molten pool is gently radiated and conducted in a direction perpendicular to the incident direction of the laser beam L. Thereby causing the molten pool to grow. The molten pool is expanded to the two resin members 1,2 through a part of the contact portion N. When the molten pool is cooled, the melted portions of the two resin members 1,2 solidify. Thereby, the welding portion M is formed which is expanded while connecting the two resin members 1,2 together. The two resin members 1,2 are firmly joined at the welded contact portion N. Thereby, the laser welded body 10 was obtained.

In step D, a cooling process of blowing air and/or an inert gas onto the incident surface of the laser beam L may also be performed. When gas is generated from the two resin members 1 and 2 by the laser welding, the gas may be purged by using a gas processing device.

Another embodiment of a laser welded body 10 using the laser weak absorption resin member 1 and the laser absorption resin member 2 will be described below with reference to fig. 2 and 3. Absorbance a of the laser weakly absorbent resin member 1₁And the absorbance a of the laser-absorbing resin member 2₂With values in the same ranges as described above.

Fig. 2(a) is a schematic cross-sectional view showing another aspect of manufacturing the laser welded body 10. Absorbance a of resin members 1 and 2₁、a₂All having values in the same ranges as described above. The laser welded body 10 has a butt portion B. The edge portion of the laser weak absorption resin member 1 and the edge portion of the laser absorption resin member 2, which are suitable objects to be irradiated with the laser beam, are brought into contact and abutted with each other. Thereby forming a butt joint portion B as a facing portion. The butt portion B is irradiated with a laser beam L from the side of the laser weak absorption resin member 1 on the upper surface of the laser weak absorption resin member 1 at an angle inclined with respect to the upper surface thereof. A part of the laser beam L is absorbed into the laser weak absorption resin member 1. The other part of the laser beam L passes through the laser weak absorption resin member 1 and reaches and is absorbed by the edge portion where the laser absorption resin member 2 abuts. Both of the resin members 1,2 generate heat and melt at the butt joint portion B. Therefore, the two resin members 1 and 2 are welded together at the butt portion B to form the laser welded body 10.

Fig. 2(b) is a schematic cross-sectional view showing another manufacturing perspective of the laser welded body 10. The laser light weak absorption resin member 1 as an object suitable for irradiation with a laser beam is divided into a first laser light weak absorption resin member sheet 1a and a second laser light weak absorption resin member sheet 1 b. The two resin members 1 and 2 are stacked to form a contact portion N, thereby forming a first weak laser absorptionContact portion N between resin member sheet 1a and laser-absorbing resin member 2_1a-2And contact portions N of the second laser weak absorption resin member sheet 1b and the laser absorption resin member 2 are formed_1b-2. The edge portions of the laser weak absorption resin member sheets 1a and 1b are butted and brought into contact with each other. Butt portion B of laser welded body 10 is opposite to contact portion N_1a-2、N_1b-2Is formed vertically. The two laser weak absorption resin member sheets 1a, 1b and the laser absorption resin member 2 have the same outer size and outer shape. The laser weak absorption resin member 1 protrudes from both side edges of the laser absorption resin member 2. Absorbance a of the first laser weak absorption resin member sheet 1a_1-1A of absorbance with respect to the second laser weak absorption resin member sheet 1b_1-2May be the same or different, as long as the absorbance a at the laser weak absorption resin member 1₁Within the range of 0.09 to 0.9. Absorbance a of the laser-absorbing resin member 2₂The amount of the surfactant is 3.0 to 15. The butt portion B is irradiated with the laser beam L from directly above the butt portion B. The two laser weak absorption resin member pieces 1a, 1B are welded at the butt joint portion B, and the laser weak absorption resin member 1 and the laser absorption resin member 2 are in contact with the butt joint portion N_1a-2、N_1b-2And (6) welding. Thereby forming a contact portion N and a butt portion B_1a-2、N_1b-2And a laser welded body 10 welded thereto.

Fig. 2(c) is a schematic cross-sectional view showing another aspect of manufacturing the laser welded body 10. Laser weak absorption resin members 1 suitable for an object to be irradiated with a laser beam are disposed on the upper side and laser absorption resin members 2 are disposed on the lower side, respectively. The laser-absorbing resin member 2 is divided into a first laser-absorbing resin member sheet 2a and a second laser-absorbing resin member sheet 2 b. By laminating the two resin members 1 and 2, a contact portion N between the laser weak absorption resin member 1 and the first laser absorption resin member sheet 2a is formed_1-2aAnd contact portions N of the laser weak absorption resin member 1 and the second laser absorption resin member sheet 2b are formed_1-2b. The edge portions of the laser-absorbing resin member sheets 2a and 2b are in contact with each other. Laser weldingThe butt portion B of the joint body 10 is opposite to the contact portion N_1-2a、N_1-2bIs formed vertically. The laser weak absorption resin member 1 and the two laser absorption resin member sheets 2a, 2b have the same outer dimensions and outer shapes. The laser light absorbing resin member 2 protrudes from both side edges of the laser light weak absorbing resin member 1. Absorbance a of the laser weakly absorbent resin member 1₁The amount is 0.09 to 0.9 as described above. Absorbance a of the first laser light-absorbing resin member sheet 2a_2-1A with the absorbance of the second laser-absorbing resin member sheet 2b_2-2May be the same or different, as long as the absorbance a in the laser-absorbing resin member 2 is₂3.0 to 15. The laser beam L is irradiated from the side of the laser weak absorption resin member to the butt joint portion B. The laser weak absorption resin member 1 melts at a site where the laser beam L is incident, and the laser absorption resin member 2 melts at the butt joint site B. As a result, the laser weak absorption resin member 1 and the two laser absorption resin member sheets 2a and 2b are brought into contact with each other at the contact portion N_1-2a、N_1-2bAnd (6) welding. The two laser-absorbing resin member sheets 2a and 2B are welded together at the butt joint portion B. Laser welding a welding portion M of a body 10 to a contact portion N_1-2a、N_1-2bAnd the docking site B. Thereby, the laser welded body 10 welded to the butt portion B and the contact portion N is formed.

Fig. 2(d) is a schematic cross-sectional view showing another aspect of manufacturing the laser welded body 10. The rectangular laser weak absorption resin member 1 has a first splice portion 1c on its side surface. The rectangular laser-absorbing resin member 2 has a second splice portion 2c on its side surface. The two splices 1c, 2c each have a step profile of the same height. The two splices 1c, 2c are fitted to each other in a staggered manner. Thus, the two resin members 1 and 2 are stacked to form a contact portion N and an upper butt portion B where the edges of the two resin members 1 and 2 are butted₁And a lower butt joint part B₂. In the contact portion N, the first splice portion 1c is located on the incident side of the laser beam L. The laser weak absorption resin member 1 and the laser absorption resin member 2 are welded at the contact portion N and pass throughThe laser beam L from the first splice part 1c side is irradiated and integrated. Further, as shown by the two-dot chain line in fig. 2(d), the laser beam L may scan the surface of the first splice portion 1c of the laser weakly absorbent resin member 1 in the X direction (see fig. 1(a) and the inward direction in fig. 2 (d)) and the Y direction perpendicular thereto (the horizontal direction in fig. 2 (d)). The two resin members 1,2 are extensively welded at the contact portion N and also at the two butt portions B₁、B₂And (6) welding. Since the welding portion M is formed over a wide range, the welding strength between the two resin members 1 and 2 can be further improved.

The butt portion B of the laser welded body 10 may be formed at an angle with respect to the laser irradiated surface of the laser weakly absorbent resin member 1. In the laser welded body 10 shown in fig. 3, the edges of the laser weakly absorbent resin member 1 and the laser absorptive resin member 2 have inclined surfaces that make the same angle with respect to the surfaces thereof, respectively. Edges of two resin members 1,2 formed to have inclined surfaces are butted alternately so that acute-angle sides of the inclined edges are located on a laser light irradiation surface (upper surface in fig. 3) of the laser light weak absorption resin member 1. Thereby, the inclined butt joint portion B is formed. The laser beam L is irradiated approximately perpendicularly to the inclined butt portion B. Since the welding site M is formed over a wide range at the inclined butt joint site B, the two resin members 1,2 in the laser welded body 10 are firmly joined. The laser beam L may be irradiated so as to be substantially perpendicular to the laser irradiation surface of the laser weak absorbent resin member 1, or may be irradiated so as to be at an angle with respect to the inclined butt portion B.

Fig. 4 is a schematic cross-sectional view showing a manufacturing scene of another laser welded body 10. The laser welded body 10 may have a cylindrical shape. Both the laser weak absorption resin member 1 and the laser absorption resin member 2 have a cylindrical shape with both ends open. The inner diameter of the laser weak absorption resin member 1 is slightly larger than the outer diameter of the laser absorption resin member 2. The laser light-absorbing resin member 2 is inserted into the cavity of the laser light weak absorbing resin member 1 with a play that allows the laser light-absorbing resin member 2 to be removed from and inserted into the laser light weak absorbing resin member 1. The inner peripheral surface of the laser weak absorption resin member 1 and the outer peripheral surface of the laser absorption resin member 2 are in contact with each other with a local slight gap. Thereby, the contact portion N is formed. The length of the laser weak absorption resin member 1 is shorter than the length of the laser absorption resin member 2. The laser light absorbing resin member 2 protrudes from the open end of the laser light weak absorbing resin member 1. The laser beam L is irradiated onto the outer peripheral surface of the laser weakly absorbent resin member 1 in such a manner as to make one round of turn. The two resin members 1,2 are welded together at the contact portion N, thereby forming a laser welded body 10.

The laser beam L is preferably infrared rays having a longer wavelength than that of visible radiation in the range of 800 to 1600nm, and preferably has an oscillation wavelength in the range of 800 to 1100 nm. As examples of the laser beam, a solid-state laser (Nd: Yttrium Aluminum Garnet (YAG) excitation and/or semiconductor laser excitation), a semiconductor laser, a tunable diode laser, a titanium sapphire laser (Nd: YAG excitation) are preferably used. As other examples, a halogen lamp or a xenon lamp that generates infrared rays having a wavelength of 700nm or more may be used. The laser beam L may be irradiated perpendicularly, or may be irradiated at an angle with respect to the surface of the object suitable for irradiation with the laser beam, or may be irradiated in one direction or a plurality of directions. The output power of the laser beam L corresponds to the scanning speed and absorbance a of each of the resin members 1,2₁、a₂To adjust. The output power is preferably 10 to 500W, more preferably 30 to 300W.

When a halogen lamp that generates infrared rays having a wavelength of 700nm or more is used, for example, a halogen lamp arranged in a band shape is exemplified as the lamp shape. Examples of laser irradiation modalities include: a scanning type that can irradiate a laser beam over a wide range by moving a lamp; a shielding type in which a resin member to be welded moves; and a simultaneous irradiation type of irradiating the resin members to be welded from a plurality of directions simultaneously with the lamps. Conditions such as the irradiation width of infrared rays, irradiation time, and irradiation energy can be appropriately adjusted. Since the halogen lamp has an energy distribution centered on the near-infrared region, energy may exist on a shorter wavelength side of the energy distribution, that is, in a visible light region. In this case, since a welding scar may be formed on the surface of the resin member irradiated with the radiation, a cut filter may be used to shield energy in the visible light region.

Absorption coefficient epsilon of laser beam absorbers such as nigrosine sulfate_d(ml/g.cm) is 1000 to 8000 (ml/g.cm), preferably 1000 to 6000 (ml/g.cm), and more preferably 3000 to 6000 (ml/g.cm). Absorption coefficient (. di-elect cons.) (. Absorbance.). epsilon.)_dThe measurement process of (a) is as follows: accurately weighing 0.05g of laser beam absorbent, and dissolving in a solvent such as N, N-Dimethylformamide (DMF) with a 50ml measuring flask; diluting 1ml of the obtained solution with DMF in a 50ml measuring flask to prepare a measurement sample; then, the absorbance of the measurement sample was measured using a spectrophotometer (product name: UV1600PC, manufactured by Shimadzu corporation).

The preferable thickness of the two resin members 1 and 2 is 200 to 5000 μm. When the thickness is less than 200 μm, it is difficult to control the energy of the laser beam. When too much or too little melting occurs during laser welding, breakage may occur due to overheating, or the resulting joint strength may be insufficient due to too little heat. On the other hand, if the thickness is more than 5000 μm, the distance from the portion to be welded is large, and the laser beam incident on the laser weak absorption resin member 1 is attenuated and cannot be transmitted to the inside thereof, so that the resulting bonding strength is insufficient.

The thermoplastic resin contained in the two resin members 1,2 is not limited as long as it is a known resin that can contain a laser beam absorber.

Examples of the thermoplastic resin include the following: polyphenylene sulfide resin (PPS); polyamide resin (NYRON (registered trademark), PA); polyolefin resins such as polyethylene resin (PE) and polypropylene resin (PP); polystyrene resin (PS); a polymethylpentene resin; a methacrylic resin; acrylic polyamide resin; ethylene vinyl alcohol resin (EVOH); a polycarbonate resin; polyester resins such as polyethylene terephthalate resin (PET) and polybutylene terephthalate resin (PBT); a polyacetal resin; a polyvinyl chloride resin; an aromatic vinyl resin; polyvinylidene chloride resin; a polyphenylene ether resin; a polyarylate resin; a polyallylsulfone resin; a polyphenylene ether resin; acrylic resins such as acryl polyamide resin and polymethyl methacrylate resin (PMMA); a fluorocarbon resin; and a liquid crystal polymer.

The thermoplastic resin may be a copolymer resin made of a plurality of monomers constituting the above thermoplastic resin. Specific examples of the copolymer resin are AS copolymer resin (acrylonitrile-styrene), ABS copolymer resin (acrylonitrile-butadiene-styrene), AES (acrylonitrile-EPDM-styrene) copolymer resin, PA-PBT copolymer resin, PET-PBT copolymer resin, PC-PBT copolymer resin, PS-PBT copolymer resin, and PC-PA copolymer resin. Other specific examples of copolymer resins are: thermoplastic elastomers such as polystyrene thermoplastic elastomers, polyolefin thermoplastic elastomers, polyurethane thermoplastic elastomers, and polyester thermoplastic elastomers; synthetic wax or natural wax containing the above resin as a main component. Further, the molecular weight of the thermoplastic resin is not limited. These thermoplastic resins may be used alone or in combination of two or more.

The thermoplastic resin is preferably: a polyamide resin; a polycarbonate resin; a polypropylene resin; polyester resins such as polybutylene terephthalate resins; polyphenylene sulfide resin. Among these resins, polyamide resins and polycarbonate resins are more preferable from the viewpoint of good compatibility with laser beam absorbers such as nigrosine.

The polyamide resin in the present invention means a polyamide polymer having an amide group (-CONH-) in its molecule and being meltable by heating. The preferred polyamide resin is a polyamide resin containing the following salt as the structural unit (a). The salt is at least one selected from the group consisting of a salt composed of an aliphatic diamine and an aromatic dicarboxylic acid and a salt made of an aromatic diamine and an aliphatic dicarboxylic acid. The ratio of the structural unit (a) to the total structural units of the polyamide resin is preferably 30 mol% or more, and more preferably 40 mol% or more. More specifically, it may be exemplified by various polyamide resins such as a lactam polycondensation product, a polycondensation product of a diamine and a dicarboxylic acid, a polycondensation product of an ω -aminocarboxylic acid, and a polyamide resin copolymer and a blend resin produced therefrom. As the lactam used as the raw material for the polycondensation of the polyamide resin, for example, epsilon-caprolactam, enantholactam, caprylolactam, laurolactam, alpha-pyrrolidone, alpha-piperidone, omega-laurolactam and the like are included.

As the diamine, there are included: aliphatic diamines such as butanediamine, pentanediamine, hexanediamine, octanediamine, undecanediamine, dodecanediamine, 2-methylpentanediamine, (2,2, 4-or 2,4,4-) trimethylhexanediamine, nonanediamine and 5-methylnonanediamine; alicyclic diamines such as 1, 3-bis (aminomethyl) cyclohexane, 1, 4-bis (aminomethyl) cyclohexane, 1, 3-diaminocyclohexane, 1, 4-diaminocyclohexane, 1, 3-diaminomethyl-3, 5, 5-trimethylcyclohexane, bis (4-aminocyclohexyl) methane, bis (3-methyl-4-aminocyclohexyl) methane, 2-bis (4-aminocyclohexyl) propane, bis (aminomethyl) decalin, bis (aminomethyl) tricyclodecane, bis (aminopropyl) piperazine and aminoethylpiperazine; aromatic diamines such as m-xylylenediamine (MXDA), p-xylylenediamine, p-phenylenediamine, bis (4-aminophenyl) ether and bis (aminomethyl) naphthalene.

As dicarboxylic acids, there are included: aliphatic dicarboxylic acids such as adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, glutaric acid, pimelic acid, undecanedioic acid, dodecanedioic acid (dodecadioic acid), hexadecanedioic acid (hexadecanedioic acid), hexadecenedioic acid (hexadecanedioic acid), eicosanedioic acid, diglycolic acid, and 2,2, 4-trimethyladipic acid; alicyclic dicarboxylic acids such as 1, 4-cyclohexanedicarboxylic acid; aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, 5-sodium sulfoisophthalate, hexahydroterephthalic acid, hexahydroisophthalic acid, and xylenedicarboxylic acid.

As the omega-aminocarboxylic acid, 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, p-aminomethylbenzoic acid, 2-chloro-p-aminomethylbenzoic acid, 2-methyl-p-aminomethylbenzoic acid and the like are included.

As the polyamide resin, polyamide 4, polyamide 6I, polyamide 11, polyamide 12, polyamide 46, polyamide 56, polyamide 66, polyamide 69, polyamide 610, polyamide 612, polyamide 6T, polyamide 96, polyamide 9T, amorphous polyamide, high-melting polyamide, polyamide RIM, polyamide MXD6, polyamide MP6, polyamide MP10, and an aramid resin containing two or more thereof, a semiaramid resin, an aliphatic polyamide resin, a copolymer thereof, and the like are included. As copolymers, polyamide 6/12 copolymer, polyamide 6/66 copolymer, polyamide 66/6I copolymer, polyamide 6I/6T copolymer, polyamide 6/66/610 copolymer, polyamide 6/66/11/12 copolymer and crystalline polyamide/amorphous polyamide copolymer are included. Further, the polyamide resin may be a mixed polymer of a polyamide resin and another synthetic resin. Examples of mixed polymers are polyamide/polyester mixed polymers, polyamide/polyphenylene ether mixed polymers, polyamide/polycarbonate mixed polymers, polyamide/polyolefin mixed polymers, polyamide/styrene/acrylonitrile mixed polymers, polyamide/acrylate mixed polymers and polyamide/silicone mixed polymers. These polyamide resins may be used alone or in combination of two or more.

Polyphenylene Sulfide (PPS) resin is mainly composed of[Is substituted or unsubstituted phenylene]Polymers of the thienylene repeat units shown. The PPS resin is prepared by polymerizing a monomer synthesized by reacting p-dichlorobenzene with an alkali metal sulfide at high temperature and high pressure. PPS resins are roughly classified into two types. One is a linear type prepared only by a polymerization process using a polymerization auxiliary to have a desired degree of polymerization. The other is a crosslinked type prepared by thermally crosslinking a polymer having a low molecular weight in the presence of oxygen. The linear PPS resin is preferable because of its excellent transmittance. The melt viscosity of the PPS resin is not limited as long as melt kneading can be performed. The melt viscosity is preferably 5 to 2000 pas, more preferably 100 to 600 pas.

The PPS resin may be a polymer alloy. Examples of polymer alloys are PPS/polyolefin alloys, PPS/polyamide alloys, PPS/polyester alloys, PPS/polycarbonate alloys, PPS/polyphenylene ether alloys, PPS/liquid crystal polymer alloys, PPS/polyimide alloys, and PPS/polysulfone alloys. PPS resin has chemical resistance, heat resistance, and high strength, and is therefore preferably used for electronic parts and automobile parts.

Examples of the polyester resin are a polyethylene terephthalate resin prepared by a polycondensation reaction of terephthalic acid and ethylene glycol, and a polybutylene terephthalate resin prepared by a polycondensation reaction of terephthalic acid and butanediol. Examples of the other polyester resin are copolymers in which a part of the terephthalic acid component and/or a part of the diol component is substituted with a substituent such as an alkyl group having 1 to 4 carbon atoms. In the terephthalic acid component, the substituent is 15 mol% or less (e.g., 0.5 to 15 mol%), preferably 5 mol% or less (e.g., 0.5 to 5 mol%). And/or, in the diol component such as ethylene glycol and butylene glycol, the substituent is 15 mol% or less (e.g., 0.5 to 15 mol%), preferably 5 mol% or less (e.g., 0.5 to 5 mol%). The polyester resin may be used alone or in combination of two or more.

As the dicarboxylic acid compound constituting the polyester resin, a derivative for forming an aromatic dicarboxylic acid or ester is particularly preferably used. Examples of aromatic dicarboxylic acids are terephthalic acid, isophthalic acid, phthalic acid, 1, 5-naphthalenedicarboxylic acid, 2, 6-naphthalenedicarboxylic acid, biphenyl-2, 2' -dicarboxylic acid, biphenyl-3, 3' -dicarboxylic acid, biphenyl-4, 4' -dicarboxylic acid, diphenyl ether-4, 4' -dicarboxylic acid, diphenylmethane-4, 4' -dicarboxylic acid, diphenylsulfone-4, 4' -dicarboxylic acid, diphenylisopropyl-4, 4' -dicarboxylic acid, 1, 2-bis (phenoxy) ethane-4, 4' -dicarboxylic acid, anthracene-2, 5-dicarboxylic acid, anthracene-2, 6-dicarboxylic acid, p-phenylene-4, 4' -dicarboxylic acid, pyridine-2, 5-dicarboxylic acids, and the like. Terephthalic acid is preferred. These aromatic dicarboxylic acids may be used by mixing two or more thereof. It is well known that dimethyl esters and the like can be used in polycondensation reactions as ester-forming derivatives in addition to the free acids. In addition, small amounts, one or more aliphatic dicarboxylic acids and/or alicyclic dicarboxylic acids may also be mixed and used together with the above-described aromatic dicarboxylic acids. Examples of aliphatic dicarboxylic acids are adipic acid, azelaic acid, dodecanedioic acid, sebacic acid, and the like. Examples of alicyclic dicarboxylic acids are 1, 2-cyclohexanedicarboxylic acid, 1, 3-cyclohexanedicarboxylic acid, 1, 4-cyclohexanedicarboxylic acid, and the like.

The dihydroxy compound constituting the polyester resin includes aliphatic diols, alicyclic diols, and mixtures thereof. Examples of aliphatic diols are ethylene glycol, propylene glycol, butylene glycol, hexylene glycol, neopentyl glycol, 2-methylpropane-1, 3-diol, diethylene glycol, triethylene glycol, and the like. Examples of cycloaliphatic diols are cyclohexane-1, 4-dimethanol and the like. In addition, if the amount is small, one or more long-chain diols with the molecular weight of 400-6000 can be copolymerized. Examples of long chain diols are polyethylene glycol, poly-1, 3-propanediol, polybutylene glycol, and the like. Aromatic diols such as hydroquinone, resorcinol, naphthalene diol, dihydroxy diphenyl ether, 2-bis (4-hydroxyphenyl) propane, and the like may also be used. In order to introduce a branched structure, a small amount of a trifunctional monomer may be used together therewith in addition to the above-mentioned bifunctional monomer. Examples of trifunctional monomers are trimellitic acid, trimesic acid, pyromellitic acid, pentaerythritol, trimethylolpropane, etc. In order to adjust the molecular weight, a monofunctional compound such as an aliphatic acid may be slightly used together therewith.

A polyester resin mainly containing a polycondensation product of a dicarboxylic acid and a diol is used. That is, the polycondensation product is contained in an amount of 50 mass% or more, preferably 70 mass% or more, in the entire resin. Preferred dicarboxylic acids are aromatic dicarboxylic acids. Preferred diols are aliphatic diols. The acid component more preferably contains 95% by mass or more of terephthalic acid. The alcohol component more preferably contains 95% by mass or more of polyalkylene terephthalate as an aliphatic diol. Examples thereof are polybutylene terephthalate and polyethylene terephthalate. Polyester resins that are almost homopolyesters are preferred. That is, 95% by mass or more of the total resin is the terephthalic acid component and the 1, 4-butanediol or ethylene glycol component. The polyester resin is preferably polybutylene terephthalate as a main component. The polybutylene terephthalate may be a copolymer of a polyalkylene glycol such as isophthalic acid, dimer acid, and polytetramethylene glycol (PTMG).

Examples of the polyolefin resin are homopolymers of α -olefins and copolymers thereof, and copolymers of these polymers with other copolymerizable unsaturated monomers (the copolymers may be block copolymers, random copolymers and graft copolymers). Examples of alpha-olefins are ethylene, propylene, 1-butene, 3-methyl-1-butene, 4-methyl-1-pentene and 1-octene. Specifically, polyethylene resins, polypropylene resins, poly-1-butene and poly-4-methyl-1-pentene may be mentioned. Examples of the polyethylene resin are high density polyethylene, medium density polyethylene, low density polyethylene, linear low density polyethylene, ethylene-vinyl acetate copolymer and ethylene-ethyl acrylate copolymer. Examples of the polypropylene resin are a polypropylene homopolymer, a propylene-ethylene block copolymer or random copolymer, and a propylene-ethylene-1-butene copolymer. These polyolefin resins may be used alone or in combination of two or more. Among them, polyethylene resin and/or polypropylene resin is preferable. More preferably a polypropylene resin. There is no limitation on the molecular weight of the polypropylene resin. Polypropylene resins of a wide range of molecular weights can be used.

Further, as the polyolefin resin, an acid-modified polyolefin modified with an unsaturated carboxylic acid or a derivative thereof, and a foamed resin like foamed polypropylene containing a foaming agent can be used. Also, the polyolefin resin may further include: ethylene- α -olefin copolymer rubber; ethylene- α -olefin-non-conjugated diene compound copolymers such as Ethylene Propylene Diene Monomer (EPDM); an ethylene-aromatic monovinyl compound-conjugated diene compound copolymer rubber; and/or hydrogenated rubbers thereof.

The polycarbonate resin is a thermoplastic resin having a carbonate bond in its main chain. Polycarbonate resin has excellent mechanical properties, heat resistance, cold resistance, electrical properties and transparency, and is an engineering plastic. As the polycarbonate resin, any of an aromatic polycarbonate resin and an aliphatic polycarbonate resin may be used. Aromatic polycarbonate resins are preferred. Aromatic polycarbonate resins are thermoplastic polymers obtained by the reaction of: an aromatic dihydroxy compound or this compound and a small amount of a polyhydroxy compound are reacted with phosgene or a carbonic acid diester. The aromatic polycarbonate resin may have a branched chain or may be a copolymer. The preparation method of the aromatic polycarbonate resin is not limited. The aromatic polycarbonate resin can be prepared by a conventionally known method such as a phosgene method (interfacial method) and a melt method (transesterification method). In addition, when an aromatic polycarbonate resin prepared by a melt method is used, the amount of OH groups as terminal groups can be optimized.

Examples of the aromatic dihydroxy compound as the raw material of the aromatic polycarbonate resin are 2, 2-bis (4-hydroxyphenyl) propane (i.e., bisphenol a), tetramethylbisphenol a, bis (4-hydroxyphenyl) -p-diisopropylbenzene, hydroquinone, resorcinol, 4-dihydroxybiphenyl and the like. The preferred compound is bisphenol a. One or more tetraalkyl phosphonium sulfonates may be used in combination with the aromatic dihydroxy compounds described above. The branched aromatic polycarbonate resin can be obtained by substituting a part of the above aromatic dihydroxy compound with a branching agent compound. Examples of such branching agent compounds are: polyhydric compounds such as phloroglucinol, 4, 6-dimethyl-2, 4, 6-tris (4-hydroxyphenyl) -2-heptene, 4, 6-dimethyl-2, 4, 6-tris (4-hydroxyphenyl) heptane, 2, 6-dimethyl-2, 4, 6-tris (4-hydroxyphenyl) -3-heptene, 1,3, 5-tris (4-hydroxyphenyl) benzene, and 1,1, 1-tris (4-hydroxyphenyl) ethane; and/or 3, 3-bis (4-hydroxyaryl) oxindole (i.e., isatin bisphenol), 5-chloroisatin, 5, 7-dichloroisatin, 5-bromoisatin, and the like. The amount of these compounds for substitution is usually 0.01 to 10 mol%, preferably 0.1 to 2 mol%, relative to the aromatic dihydroxy compound.

Preferred aromatic polycarbonate resins are polycarbonate resins derived from 2, 2-bis (4-hydroxyphenyl) propane or polycarbonate copolymers derived from 2, 2-bis (4-hydroxyphenyl) propane and other aromatic dihydroxy compounds. In addition, the aromatic polycarbonate resin may have a polycarbonate resin as a main body, and may be a copolymer made of a polycarbonate resin and a polymer or oligomer having a siloxane structure. A mixture of two or more of the above aromatic polycarbonate resins may also be used.

When aniline black or carbon black, which is a black colorant, is used as the laser beam absorber, the laser weakly absorbent resin member 1 and the laser absorbing resin member 2 have a color tone from gray to black depending on the content thereof. Especially in order to obtain a relatively high absorbance a in the range of 3.0 to 15₂The laser beam absorbing resin member 2 contains more laser beam absorber than the laser weak absorbing resin member 1. Therefore, the laser-absorbing resinThe member 2 is typically black. On the other hand, in the laser weak absorption resin member 1, the absorbance a is set to be₁The content of the laser beam absorber is determined under the condition of 0.09-0.9. Therefore, the laser light weak absorption resin member 1 is insufficient in color density and may take a light color such as gray. In this case, a colorant may be added to the laser weak absorption resin composition thereof to impart a desired color density to the laser weak absorption resin member 1. Thereby, when the two resin members 1,2 have the same color, the boundary and the welding mark between them are reduced.

The coloring of the thermoplastic resin is for the purpose of achieving a decorative effect, a color discrimination effect, an improvement in light resistance of a molded product, and protection or shielding of contents. Black coloration is strongly demanded in industry.

The colorant is appropriately selected depending on the hue and color density of the thermoplastic resin contained in the resin composition used for producing the two resin members 1,2, and further in consideration of the application and the use conditions. For example, when a dark black color is imparted to the two resin members 1,2, a black colorant can be prepared by combining various colorants. Examples of colorant combinations are: a combination of a blue colorant, a red colorant, and a yellow colorant; a combination of violet and yellow colorants; and combinations of green and red colorants. The coloring of the oil-soluble dye is suitable because the oil-soluble dye exhibits good dispersibility and compatibility with the resin. In particular, nigrosine can be used as both a black coloring agent and a laser beam absorber, and can impart higher bonding strength, and thus can be preferably used.

The structure of the colorant and its hue are not limited. Colorants containing various organic dyes and pigments are exemplified. Examples of dyes and pigments are azos, azomethines, anthraquinones, quinacridones, dioxazines, diketopyrrolopyrroles, anthrapyridones, isoindolinones, indanthrones, perinones, perylenes, indigoids, thioindigoids, quinophthalones, quinolines and triphenylmethanes.

Preferred colorants are products combining various dyes having visible light absorption, sufficient compatibility with thermoplastic resins, and low scattering of laser beams. More preferred colorants are products having the following properties: is less likely to be discolored by high temperature generated when the two resin members 1,2 are molded and high temperature generated when they are melted by laser beam irradiation; has excellent heat resistance; the optical film is non-absorptive and transmissive to the wavelength of the near infrared range of the laser beam. As the colorant having transparency to the wavelength of the laser beam, a colorant containing an anthraquinone dye is exemplified.

The anthraquinone dye is preferably an anthraquinone oil soluble dye. For example, dyes are commercially available that are specifically represented by the color index as follows: c.i. solvent blues 11, 12, 13, 14, 26, 35, 36, 44, 45, 48, 49, 58, 59, 63, 68, 69, 70, 78, 79, 83, 87, 90, 94, 97, 98, 101, 102, 104, 105, 122, 129, and 132; c.i. disperse blues 14, 35, 102 and 197; c.i. solvent green 3, 19, 20, 23, 24, 25, 26, 28, 33 and 65; and c.i. solvent violet 13, 14, 15, 26, 30, 31, 33, 34, 36, 37, 38, 40, 41, 42, 45, 47, 48, 51, 59 and 60.

Anthraquinone dyes having a maximum absorption wavelength of 590 to 635nm can be exemplified. Anthraquinone dyes generally appear blue and have high visibility compared to anthraquinone green dyes. When the black mixed colorant is prepared by combination, a deep black colorant having high colorability can be obtained by combining a red dye and/or a yellow dye with an anthraquinone blue dye by subtractive color mixing.

The anthraquinone dye preferably has a transmittance of 60 to 95% for a 940nm laser beam. Examples of commercially available anthraquinone dyes include "NUBIAN (registered trademark) BLUE series" and "opas (registered trademark) BLUE series" (both of which are trade names and are commercially available from oriental CHEMICAL industry co., LTD).

The preferred conductivity of the anthraquinone dye is 50 to 500 [ mu ] S/cm. Accordingly, the insulating properties of the resin members 1 and 2 are increased, and therefore, the laser welded body 10 is suitable for resin members requiring high insulating properties, such as parts of electric and electronic equipment and parts of precision equipment.

The conductivity is measured as follows: dispersing anthraquinone dye with 5g amount into 500mL ion exchange water, and then recording the weight; boiling the ion-exchanged water in which the anthraquinone dye has been dispersed for 10 minutes to extract an ionic component, and then filtering; adding ion exchange water to the obtained filtrate until the weight thereof is the same as a previously measured weight; the conductivity of the solution was measured using a conductivity meter (manufactured by DKK-TOA, trade name: AOL-10).

Examples of dye combinations are: anthraquinone blue dyes and other blue, red and yellow dyes in combination; and combinations of anthraquinone blue and green dyes, red dyes and yellow dyes. Examples of red and yellow dyes are azo dyes, quinacridone dyes, dioxazine dyes, quinophthalone dyes, perylene dyes, perinone dyes, isoindolinone dyes, azomethine dyes, triphenylmethane dyes and red or yellow anthraquinone dyes. These dyes may be used alone or in combination of two or more. Examples of the dye for imparting good coloring to the laser-absorbing resin composition include a perinone red dye, an anthraquinone red dye and an anthraquinone yellow dye.

It is preferable to use a combination of the above anthraquinone blue dye and red dye having a maximum absorption wavelength range of 590 to 635 nm. As a suitable example, a perinone dye may be mentioned. The perinone dyes have good heat resistance and are usually red in color. Examples of commercially available RED dyes include "NUBIAN (registered trademark) RED series" and "opas (registered trademark) RED series" (both of which are trade names and are available from eastern chemical industry co., ltd).

Examples of the perinone dyes are in particular: c.i. solvent orange 60; c.i. solvent red 135, 162, 178 and 179.

Examples of anthraquinone red dyes (including anthrapyridone dyes) are: c.i. solvent red 52, 111, 149, 150, 151, 168, 191, 207, and 227; c.i. disperse red 60. The perinone dyes and anthraquinone red dyes are indicated by a color index and are commercially available.

A preferred dye suitable for combination with the anthraquinone red dye is an anthraquinone yellow dye. In the colorant, the mass ratio (i)/(ii) of the mass of the (i) anthraquinone yellow dye/(ii) the mass of the blue, green and/or violet anthraquinone dye is preferably in the range of 0.15 to 1.0. Examples of commercially available anthraquinone YELLOW dyes include "NUBIAN (registered trademark) YELLOW series" and "opas (registered trademark) YELLOW series" (both of which are trade names and are available from eastern chemical industry co., ltd.).

Examples of yellow dyes include dyes represented by the following color indices: c.i. solvent yellow 14, 16, 32, 33, 43, 44, 93, 94, 98, 104, 114, 116, 133, 145, 157, 163, 164, 167, 181, 182, 183, 184, 185, and 187; c.i. vat yellows 1,2 and 3. These dyes are all commercially available.

When the laser-welded article 10 requires color fastness such as weather resistance, heat resistance, bleeding resistance, etc., a salt-forming dye obtained by combining an acid dye and an organic amine is preferably used as the oil-soluble dye. The salt-forming dye can be represented by [ acid dye anion-organic ammonium salt ]. In the colorant, the anthraquinone dye is substituted with a salt-forming dye, and for example, an anthraquinone salt-forming dye represented by [ acid dye anion/organic ammonium salt ] is used. Thereby, the color fastness of the colorant is improved.

Examples of the anthraquinone acid dye used for the salt-forming dye include anthraquinone dyes having a single sulfonic acid group in a single molecule and represented by the following color indices: especially c.i. acid blue 25, 27, 40, 41, 43, 45, 47, 51, 53, 55, 56, 62, 78, 111, 124, 129, 215, 230 and 277; c.i. acid green 37; and c.i. acid violet 36, 41, 43, 51 and 63. These dyes are all commercially available.

Examples of the anthraquinone acid dye other than the above-mentioned anthraquinone acid dyes include anthraquinone dyes having two sulfonic acid groups in a single anthraquinone molecule and represented by the following color indexes: c.i. acid blue 23, 35, 49, 68, 69, 80, 96, 129:1, 138, 145, 175, 221 and 344; c.i. acid green 25, 27, 36, 38, 41, 42 and 44; and c.i. acid violet 34 and 42. These dyes are all commercially available.

Preferred anthraquinone dyes have the following structure: a substituent having a sulfonic acid group is bonded to the anilino group. The structure is contained as at least one substituent in the molecular skeleton of the anthraquinone. Anthraquinone dyes can be exemplified by: c.i. acid blue 49, 80, 96, 129:1, 138, 145 and 221; the above-mentioned c.i. acid green 25, 27, 36, 38, 41, 42 and 44; and c.i. acid violet 34.

Examples of preferred anthraquinone salt-forming dyes are anthraquinone salt-forming dyes having anilino derivatives as substituents. The anthraquinone salified dye is prepared from A^-B⁺(A^-Is an anion from anthraquinone, B⁺Is a cation derived from organic ammonium) or AB (A is a dehydrogenated residue of the molecular skeleton of anthraquinone or a dehydrogenated residue of a substituent bonded to anthraquinone, B is a dehydrogenated residue of organic ammonium). The anthraquinone salt-forming dye exhibits high compatibility with the aromatic thermoplastic resin and imparts high heat resistance thereto.

Preferred anthraquinone salt-forming dyes are represented by the following formula (1):

(wherein X and Y are each independently a hydrogen atom, a hydroxyl group, a halogen atom or an amino group; R¹～R⁵Independently of one another, a hydrogen atom, a hydroxyl group, an amino group, a nitro group, a linear or branched alkyl group having 1 to 18 carbon atoms, a linear or branched alkoxy group having 1 to 18 carbon atoms, a halogen atom, a phenoxy group or a carboxyl group; (P)^b+Is an organic ammonium ion; a and b are positive numbers of 1-2; m and n are positive numbers of 1-2; a is a hydrogen atom, a hydroxyl group, an amino group, a halogen atom or a group represented by the following formula (2):

(in the formula (2), R⁶～R¹⁰Independently of one another, a hydrogen atom, a hydroxyl group, an amino group, a nitro group, a linear or branched alkyl group having 1 to 18 carbon atoms, a linear or branched alkoxy group having 1 to 18 carbon atoms, or a halogen atom)).

Examples of the straight or branched alkyl group having 1 to 18 carbon atoms in the formulae (1) and (2) are specifically methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, neopentyl, isopentyl, sec-pentyl, 3-pentyl, tert-pentyl, hexyl, heptyl, and octyl. Examples of the straight-chain or branched alkoxy group having 1 to 18 carbon atoms are specifically a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, a sec-butoxy group, an isobutoxy group, a tert-butoxy group, an n-pentyloxy group, a neopentyloxy group, an isopentyloxy group, a sec-pentyloxy group, a 3-pentyloxy group, a tert-pentyloxy group and a hexyloxy group. Examples of halogen atoms are in particular fluorine, chlorine, bromine and iodine.

The preferred salt-forming dye represented by formula (1) is an anthraquinone salt-forming dye having two anilino derivatives as substituents in a single molecule. Thereby, thermal deterioration of the two resin members 1,2 due to heat fusion at the time of molding and laser welding can be prevented. Anthraquinone acid dyes are suitable as salt-forming dyes. Examples of the anthraquinone acid dye having two anilino derivatives as substituents in a single molecule are specifically: c.i. acid green 25, 27, 36, 38, 41, 42 and 44; c.i. acid blue 80 and 221; and c.i. acid violet 34.

Examples of preferred amines for the salt-forming dye represented by formula (1) are: aliphatic monoamines such as hexylamine, pentylamine, octylamine, 2-ethylhexylamine, di (2-ethylhexyl) amine and dodecylamine; alicyclic amines such as cyclohexylamine, dicyclohexylamine, and diazidoethylamine (dihydroaziethylamine); aliphatic, alicyclic or aromatic diamines such as butanediamine, hexanediamine, octanediamine, nonanediamine, dodecanediamine, 2-methylpentanediamine, 2-methyloctanediamine, trimethylhexanediamine, bis (p-aminocyclohexyl) methane, m-xylylenediamine and p-xylylenediamine; alkoxyalkyl amines such as 3-propoxypropylamine, bis (3-ethoxypropyl) amine, 3-butoxypropylamine, octyloxypropylamine, and 3- (2-ethylhexyloxy) propylamine; aromatic amines such as α -naphthylamine, β -naphthylamine, 1, 2-naphthyldiamine, 1, 5-naphthyldiamine and 1, 8-naphthyldiamine; aromatic alkylamines such as 1-naphthylmethylamine; alkanol group-containing amines such as N-cyclohexylethanolamine, N-dodecylethanolamine and N-dodecyliminodiethanol; guanidine derivatives such as 1, 3-diphenylguanidine, 1-o-tolylguanidine and di-o-tolylguanidine.

As the above-mentioned amine, commercially available quaternary ammonium can be used. Examples of quaternary amines are in particular: QUARTAMIN 24P, QUARTAMIN 86PcONc, QUARTAMIN 60W, QUARTAMIN 86W, QUARTAMIN D86P (distearyl diMethylammonium chloride), SANISOL C and SANISOL B-50 (available from Kao Corporation, QuartAMIN and SANISOL are registered trademarks, supra); ARQUAD 210-80E, 2C-75, 2HT-75 (dialkyl (alkyl is C)₁₄-C₁₈) Dimethylammonium chloride), 2HTflake, 2O-75I, 2HP-75, and 2HPflake (available from lion specialty CHEMICALS, Inc. (LIONSPECIALTY CHEMICALS CO., LTD.), ARQUAD is a trade name); PRIMENE MD amine (Methylenediamine), PRIMENE 81-R (hyperbranched tertiary alkyl (C)₁₂-C₁₄) Mixture of primary amine isomers), PRIMENE TOA amine (T-octylamine), PRIMENE RB-3 (mixture of T-alkyl primary amines), and PRIMENE JM-T amine (hyperbranched T-alkyl (C)₁₆-C₂₂) A mixture of primary amine isomers) (available from Dow Chemical Company, PRIMENE is a registered trademark).

The content of the colorant is 0.01 to 5 parts by mass, preferably 0.05 to 3 parts by mass, and more preferably 0.1 to 2 parts by mass, per 100 parts by mass of the thermoplastic resin. When the content of the colorant is adjusted to the above range, a resin composition for molding into two resin members 1,2 having high coloring is obtained.

In preparing the resin composition, it is preferable to prepare a master batch containing the colorant and then add the master batch to the thermoplastic resin composition. Thereby, the resin composition is free from color unevenness due to uniform dispersion of the colorant. The content of the colorant in the masterbatch is preferably 5 to 90 mass%, more preferably 20 to 60 mass%.

In addition to the colorant, various additives may be added to the raw materials of the thermoplastic resin as needed. Examples of additives are reinforcing agents, fillers, ultraviolet absorbers or light stabilizers, antioxidants, antibacterial agents, fungicides, flame retardants, mold release agents, crystal nucleating agents, plasticizers, impact modifiers, auxiliary colorants, dispersants, stabilizers, modifiers, antistatic agents, lubricants and crystallization promoters. White pigments and organic white pigments such as titanium oxide, zinc sulfate, zinc white (zinc oxide), calcium carbonate and alumina white can also be exemplified. Thereby, the colorless raw material of the thermoplastic resin can be adjusted to be colored by combining with the organic dye and the pigment.

The reinforcing agent can be freely selected as long as the product can be used for reinforcing the synthetic resin. Examples of enhancers are: inorganic fibers such as glass fibers, carbon fibers, metal fibers, calcium titanate fibers, calcium silicate fibers, sepiolite, wollastonite, rock wool and the like; and organic fibers such as aramid, polyphenylene sulfide resin, polyamide, polyester, and liquid crystal polymer. For example, when transparency is to be imparted to the resin member, glass fibers are suitable for reinforcing the resin member. The glass fiber has a fiber length of 2 to 15mm and a fiber diameter of 1 to 20 μm. The glass fibers can be freely selected, for example roving fibers and milled fibers. The glass fiber may be used alone, or two or more kinds of glass fibers may be used in combination. The content thereof is preferably 5 to 120 parts by mass with respect to 100 parts by mass of the resin members 1 and 2. If it is less than 5 parts by mass, the reinforcing effect of the glass fiber is insufficient. If it exceeds 120 parts by mass, moldability is lowered. The content thereof is preferably 10 to 60 parts by mass, more preferably 20 to 50 parts by mass.

The filler may, for example, be a particulate filler. Examples of particulate fillers are: silicates such as talc, kaolin, clay, wollastonite, bentonite, asbestos, and aluminum silicate; metal oxides such as alumina, silica, magnesia, zirconia, and titania; carbonates such as calcium carbonate, magnesium carbonate and dolomite; sulfates such as calcium sulfate and barium sulfate; glass beads, ceramic beads, boron nitride, silicon carbide and the like. In addition, the filler may also be a plate-like filler such as mica, sericite and glass flakes.

Examples of the ultraviolet absorber and the light stabilizer include benzotriazole-based compounds, benzophenone-based compounds, salicylate-based compounds, cyanoacrylate-based compounds, benzoate-based compounds, oxalic anilide-based compounds, hindered amine-based compounds, and nickel complex salts.

Examples of the antioxidant include phenolic antioxidants, phosphorus antioxidants, and sulfur antioxidants and thioether antioxidants.

Phenolic antioxidants are antioxidants having a phenolic hydroxyl group. Among them, hindered phenol antioxidants are preferably used. In the hindered phenol type antioxidant, one or two carbon atoms adjacent to the carbon atom of the aromatic ring bonded to the phenolic hydroxyl group are substituted with a substituent having 4 or more carbon atoms. The substituent having 4 or more carbon atoms may be bonded to a carbon atom of the aromatic ring through a carbon-carbon bond, and may be bonded thereto through an atom other than a carbon atom.

The phosphorus-based antioxidant is an antioxidant having a phosphorus atom. The phosphorus-based antioxidant may be: inorganic phosphate compounds such as sodium phosphite, sodium hypophosphite, and the like; or has P (OR)₃An organic antioxidant of structure. Wherein R is an alkyl group, an alkylene group, an aryl group, an arylene group, or the like. The three R's may be the same or different, and any two of the R's may be bonded together to form a ring structure. Examples of the phosphorus-based antioxidant include triphenyl phosphite, diphenyldecyl phosphite, phenyldiisodecyl phosphite, tris (nonylphenyl) phosphite, bis (2, 4-di-t-butylphenyl) pentaerythritol diphosphite, bis (2, 6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite, and the like.

The sulfur-based antioxidant is an antioxidant having a sulfur atom. Examples of the sulfur-based antioxidant include didodecyl thiodipropionate, ditetradecyl thiodipropionate, dioctadecyl thiodipropionate, pentaerythritol tetrakis (3-dodecylthiopropionate), thiobis (N-phenyl-. beta. -naphthylamine), 2-mercaptobenzothiazole, 2-mercaptobenzimidazole, tetramethylthiuram monosulfide, tetramethylthiuram disulfide, nickel dibutyldithiocarbamate, nickel isopropylxanthate, trilauryltrithiophosphite and the like. In particular, a thioether antioxidant having a thioether structure is preferably used because it receives oxygen from an oxidized substance and is reduced.

Examples of antibacterial and antifungal agents include 2- (4 '-thiazolyl) benzimidazole, 10' -oxybisphenol arsine, N- (fluorodichloromethylthio) phthalimide, and zinc bis (2-thio-1-pyridineoxide).

The flame retardant may be freely selected. Examples thereof include organic flame retardants and inorganic flame retardants such as organic halogen compounds, antimony compounds, compounds having silicon, phosphorus compounds, nitrogen compounds, and the like.

Examples of the organic halogen compound include brominated polycarbonate, brominated epoxy resin, brominated phenoxy resin, brominated polyphenylene ether resin, brominated polystyrene resin, brominated bisphenol a, pentabromobenzyl polyacrylate, tetrabromobisphenol a derivative, hexabromodiphenyl ether, tetrabromophthalic anhydride, and the like. Examples of the antimony compound include antimony trioxide, antimony pentoxide, sodium antimonate, antimony phosphate and the like. Examples of the compound having silicon include silicone oil, organosilane, and aluminum silicate. Examples of the phosphorus compound include triphenyl phosphate, triphenyl phosphite, phosphate ester, polyphosphoric acid, ammonium polyphosphate, red phosphorus, and phosphazene compounds containing a bond of a phosphorus atom and a nitrogen atom in the main chain such as phenoxyphosphazene and aminophosphazene, and the like. Examples of nitrogen compounds include melamine, cyanuric acid, melamine cyanurate, urea, guanidine, and the like. Examples of the inorganic flame retardant include aluminum hydroxide, magnesium hydroxide, silicon compounds, boron compounds, and the like.

The release agent can be freely selected. Examples thereof include: montanic acid wax, lithium stearate, aluminum stearate, and other metal soaps; higher fatty acid amides such as ethylene bis stearamide; and ethylenediamine-stearic acid-sebacic acid polycondensates and the like.

The crystal nucleating agent can be freely selected. Organic nucleating agents such as rosin and inorganic nucleating agents are generally used. Examples of the inorganic nucleating agent include: metal oxides such as silica, alumina, zirconia, titania, iron oxide, and zinc oxide; metal carbonates such as calcium carbonate, magnesium carbonate, and barium carbonate; plate-like inorganic substances such as silicates, aluminum silicates and talc, and silicates; metal carbides such as silicon carbide; and metal nitrides such as silicon nitride, boron nitride, and tantalum nitride. The crystal nucleating agents may be used alone or in combination of two or more.

The plasticizer can be freely selected. Examples of the plasticizer include phthalate esters (e.g., dimethyl phthalate, butyl benzyl phthalate, diisodecyl phthalate, etc.), phosphate esters (e.g., tricresyl phosphate and 2-ethylhexyl diphenyl phosphate), sulfonamide plasticizers (e.g., n-butylbenzenesulfonamide, p-toluenesulfonamide, etc.). Further, polyester plasticizers, polyol ester plasticizers, polybasic acid ester plasticizers, bisphenol plasticizers, amide plasticizers, ester plasticizers, amide ester plasticizers, glycerin plasticizers, epoxy plasticizers (for example, epoxy triglyceride composed of epoxy-stearyl group and soybean oil), and the like can be exemplified.

Examples of the polyester plasticizer include polyesters formed from dicarboxylic acids and diols or (poly) oxyalkylene adducts thereof. The dicarboxylic acid has 2 to 12 carbon atoms, preferably 2 to 6 carbon atoms. The diol has 2 to 12 carbon atoms, preferably 2 to 6 carbon atoms. Examples of dicarboxylic acids are succinic acid, adipic acid, sebacic acid, phthalic acid, terephthalic acid, isophthalic acid, and the like. Examples of diols are propylene glycol, 1, 3-butanediol, 1, 4-butanediol, 1, 6-hexanediol, ethylene glycol, diethylene glycol, triethylene glycol, and the like. In addition, the hydroxyl group and the carboxyl group at the end of the polyester may be terminated by esterification with a monocarboxylic acid and/or a monohydric alcohol.

Examples of the polyol ester plasticizer include monoesters, diesters, or triesters of polyols or (poly) oxyalkylene adducts thereof with monocarboxylic acids, and the like. The monocarboxylic acid preferably has 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, and further preferably 1 to 4 carbon atoms. Examples of polyols are polyethylene glycol, polypropylene glycol, glycerol, the above diols, and the like. Examples of monocarboxylic acids are acetic acid, propionic acid, and the like.

Examples of the polybasic acid ester plasticizer include monoesters, diesters, or triesters of polybasic carboxylic acids with monohydric alcohols or their (poly) oxyalkylene adducts, and the like. The monohydric alcohol preferably has 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, and further preferably 1 to 4 carbon atoms. Examples of polycarboxylic acids are trimellitic acid, the above dicarboxylic acids, and the like. Examples of monohydric alcohols are methanol, ethanol, 1-propanol, 1-butanol, 2-ethylhexanol, and the like.

Examples of bisphenol plasticizers are monoesters or diesters of bisphenol with monoalkyl halides or (poly) oxyalkylene adducts thereof, and the like. The monoalkyl halide preferably has 1 to 18 carbon atoms, more preferably 2 to 14 carbon atoms, and further preferably 4 to 10 carbon atoms. Examples of bisphenols are bisphenol A, bisphenol S, and the like. Examples of monoalkyl halides are 1-octyl bromide, 1-dodecyl bromide and 2-ethylhexyl bromide.

Examples of amide plasticizers include carboxylic acid amide plasticizers and sulfonamide plasticizers. Examples of carboxylic acid amide plasticizers are amides of one or more acids with dialkylamines comprising alkyl groups having 2 to 8 carbon atoms. The acid is selected from benzoic acid, phthalic acid, trimellitic acid, pyromellitic acid and anhydrides thereof. Examples of the dialkylamine including an alkyl group having 2 to 8 carbon atoms are diethylamine, dipropylamine, dibutylamine, dihexylamine, di (2-ethylhexyl) amine, dioctylamine and the like. The molecular weight of the carboxylic acid amide plasticizer is preferably 250 to 2000, more preferably 300 to 1500, and further preferably 350 to 1000.

Examples of the ester plasticizer include monoester plasticizers, diester plasticizers, triester plasticizers, and polyester plasticizers. Examples of monoester plasticizers include benzoate plasticizers and stearate plasticizers. The benzoate plasticizer includes a benzoate composed of an adduct of benzoic acid with an aliphatic alcohol having 6 to 20 carbon atoms or with an alkylene oxide having 2 to 4 carbon atoms and an aliphatic alcohol (the number of moles of the alkylene oxide added is 10 moles or less). Examples of benzoate plasticizers are 2-ethylhexyl paraben and 2-hexyldecyl paraben. The stearate plasticizer includes stearate composed of an adduct of stearic acid with an aliphatic alcohol having 1 to 18 carbon atoms or with an alkylene oxide having 2 to 4 carbon atoms and an aliphatic alcohol (the number of addition moles of the alkylene oxide is 10 moles or less). Examples of stearates are methyl stearate, ethyl stearate, butyl stearate and hexyl stearate.

The impact modifier may be freely selected as long as the impact modifying effect of the resin is exhibited. There may be exemplified known products such as polyamide elastomers, polyester elastomers, styrene elastomers, polyolefin elastomers, acrylic elastomers, polyurethane elastomers, fluorine elastomers, silicon elastomers, acrylic core/shell elastomers and the like. Polyester elastomers and styrene elastomers are particularly preferred.

The polyester elastomer is a thermoplastic polyester having rubber properties at room temperature. The polyester elastomer is preferably a polyester block copolymer as a main component. Preferred block copolymers have as hard segments aromatic polyesters with high melting point and high crystallinity, and as soft segments amorphous polyesters and/or amorphous polyethers. The soft segment content of the polyester elastomer is at least 20 to 95 mol% in all the segments. For example, the soft segment content of the block copolymer of polybutylene terephthalate and polybutylene glycol (PBT-PTMG copolymer) is 50 to 95 mol%. The soft segment content is preferably 50 to 90 mol%, particularly 60 to 85 mol%. The polyester ether block copolymer, particularly PBT-PTMG copolymer is preferable because the transmittance thereof can be prevented from lowering.

The styrene elastomer is composed of a styrene component and an elastomer component. The styrene elastomer contains a styrene component in a proportion of 5 to 80% by mass, preferably 10 to 50% by mass, more preferably 15 to 30% by mass. In this case, as the elastomer component, conjugated diolefins such as butadiene, isoprene and 1, 3-pentadiene may be mentioned. More specifically, it may, for example, be a copolymer elastomer of Styrene and Butadiene (SBS), a copolymer elastomer of Styrene and Isoprene (SIS), or the like.

The resin members 1,2 can be manufactured by using a master batch of a thermoplastic resin composition desired to be colored. The resin as the main component of the resin members 1 and 2 and the matrix resin of the master batch may be the same or different from each other. The masterbatch may be obtained by any method. For example, a masterbatch is made by: mixing the base resin of the master batch and the powder and/or pellets of the colorant with a mixer such as a tumbler and a super mixer; the resulting mixture is heated and melted with an extruder, a batch kneader or a roll kneader, and granulated or coarsely granulated to obtain a master batch.

The resin members 1,2 may be molded by various known steps. For example, the resin members 1,2 are molded using colored pellets by using processing machines such as an extruder, an injection molding machine, and a roll mill. The resin members 1,2 can be molded by the following steps: the pellets and/or powder of the transparent thermoplastic resin, the ground colorant and optionally various additives are mixed with an appropriate mixer to obtain a resin composition, and the resin composition is molded with the above-mentioned processing machine. Further, the resin members 1,2 may also be molded by: adding a colorant to a monomer containing a suitable copolymerization catalyst; synthesizing a desired resin by polymerizing the resultant mixture; and molding the resulting resin by an appropriate method. As the molding method, the following method can be adopted: injection molding, extrusion molding, compression molding, foam molding, blow molding, vacuum molding, injection blow molding, rotational molding, calender molding, and solution casting. By adopting the above molding method, resin members 1,2 of various shapes can be obtained.