Integrated formed body
阅读说明：本技术 一体化成型体 (Integrated formed body ) 是由 铃木贵文 仙头裕一朗 今井直吉 滨口美都繁 本间雅登 于 2018-08-24 设计创作，主要内容包括：本发明的目的在于解决作为注射成型体的课题的熔接线处的强度·刚性降低,实现注射成型体的薄壁成型或者复杂形状成型等自由的设计。一体化成型体,其是具有不连续纤维和树脂的增强基材与具有不连续纤维和树脂的注射成型体一体化而成的一体化成型体,增强基材覆盖注射成型体的熔接线的局部或全部而与注射成型体一体化,增强基材的厚度Ta与一体化成型体的熔接线部的厚度T之比满足以下的关系式。Ea≠Ebw的情况下,<Image he="54" wi="700" file="DDA0002365073970000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image><Image he="73" wi="372" file="DDA0002365073970000012.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>Ea＝Ebw的情况下,Ta/T≤0.5,Ta：增强基材的厚度,T：一体化成型体的熔接线部的厚度,Ea：增强基材的弯曲弹性模量(熔接线的宽度方向),Ebw：注射成型体的熔接线的弯曲弹性模量(熔接线的宽度方向)。(The purpose of the present invention is to solve the problem of injection molded articles, such as the reduction in strength and rigidity at the weld line, and to achieve a flexible design of injection molded articles, such as thin-wall molding or complex shape molding. An integrated molded body in which a reinforcing base material having discontinuous fibers and a resin and an injection molded body having discontinuous fibers and a resin are integrated, the reinforcing base material being coated with the injection molded bodyThe body is integrated with the injection-molded body at a part or all of the weld line, and the ratio of the thickness Ta of the reinforcing base material to the thickness T of the weld line portion of the integrated body satisfies the following relational expression. In the case of Ea ≠ Ebw, when Ea is Ebw, Ta/T is less than or equal to 0.5, Ta: thickness of the reinforcing base material, T: thickness of the weld line portion of the integrated molded body, Ea: flexural modulus of reinforcing base material (width direction of weld line), Ebw: the flexural modulus of the weld line of the injection-molded body (the width direction of the weld line).)
1. An integrated molded article obtained by integrating a reinforcing base material (a) having discontinuous fibers (a1) and a resin (a2) with an injection-molded article (b) having discontinuous fibers (b1) and a resin (b2),
the reinforcing base material (a) is integrated with the injection-molded body (b) so as to cover a part or the whole of the weld line of the injection-molded body (b),
the ratio of the thickness Ta of the reinforcing base material (a) to the thickness T of the weld line portion of the integrated molded body satisfies the following relational expression:
in the case of Ea ≠ Ebw,
in the case of Ea Ebw,
Ta/T≤0.5，
ta: thickness of the reinforcing base Material (a)
T: thickness of weld line part of integrated molded body
Ea: flexural modulus of the reinforcing base Material (a) (widthwise of the weld line)
Ebw: the modulus of elasticity in bending (in the width direction of the weld line) of the weld line of the injection-molded article (b).
2. The integrated molding according to claim 1, wherein the thickness of the reinforcing base material (a) is 0.25mm or less.
3. An integrated molded article obtained by integrating a reinforcing base material (a) having discontinuous fibers (a1) and a resin (a2) with an injection-molded article (b) having discontinuous fibers (b1) and a resin (b2),
the thickness of the reinforcing base material (a) is 0.25mm or less,
the reinforcing base material (a) is integrated with the injection-molded body (b) so as to cover a part or all of the weld line of the injection-molded body (b).
4. An integrated molded article obtained by integrating a reinforcing base material (a) having discontinuous fibers (a1) and a resin (a2) with an injection-molded article (b) having discontinuous fibers (b1) and a resin (b2),
the reinforcing base material (a) is integrated by covering a part or the whole of the weld line of the injection-molded body (b),
when the integrated molded body is disposed so that the surface on which the reinforcing base material (a) is disposed faces upward in the horizontal direction and is projected from the upward direction, the reinforcing base material (a) has an area of 50% or less of the projected area of the integrated molded body,
the ratio Ea/Eb of the flexural modulus Ea of the reinforcing base material (a) to the flexural modulus Eb of the injection-molded body (b) in the non-weld line portion is 0.7 to 1.3.
5. The integrated molding according to claim 4, wherein the ratio σ a/σ b of the bending strength σ a of the reinforcing base material (a) to the bending strength σ b of the injection-molded article (b) in the non-weld line portion is 0.7 to 1.3.
6. The integrated molding according to any one of claims 1 to 5, wherein the reinforcing base material (a) has a band shape.
7. The integrated molding according to any one of claims 1 to 6, wherein the reinforcing base material (a) is integrated with the injection-molded article (b) within a distance of 2.5 to 15mm in the width direction of the weld line of the injection-molded article (b).
8. The integrated molding according to any one of claims 1 to 7, wherein the reinforcement width Wa of the reinforcement base material (a) and the thickness T of the weld line portion of the integrated molding satisfy the following relationship:
wa: width of reinforcing base (a) (width direction of weld line)
T: the thickness of the weld line portion of the integrated molded body.
9. The integrated molding according to any one of claims 1 to 8, wherein the reinforcing base material (a) exhibits substantially isotropy.
10. The integrally formed body according to any one of claims 1 to 9, wherein the reinforcing base material (a) has a linear expansion coefficient of 7 x 10-6and/K is less than or equal to.
11. The integrated molding according to any one of claims 1 to 10, wherein the reinforcing base material (a) has a flexural modulus of elasticity of 10GPa or more.
12. The integrated molding according to any one of claims 1 to 11, wherein the discontinuous fibers (a1) of the reinforcing base material (a) exhibit electrical conductivity.
13. The integrated molding according to any one of claims 1 to 12, wherein the discontinuous fibers (a1) of the reinforcing base material (a) are substantially monofilament-like and are randomly dispersed.
Technical Field
The present invention relates to an integrated molded body in which a reinforcing base material and an injection molded body are integrated.
Background
Injection molding is a molding method excellent in moldability, productivity, and economy, and is frequently used for manufacturing parts and housings of electric and electronic devices such as automobile equipment parts, personal computers, OA equipment, AV equipment, mobile phones, fixed phones, facsimiles, home electric appliances, and toy products. In recent years, with the spread of mobile electronic devices such as notebook computers, mobile phones, and mobile information terminals, injection molded articles are required to be thin, have a complicated shape, and have high strength and high rigidity.
However, the injection molded article has a problem that strength and rigidity at a weld line (weld line) are reduced. The weld line indicates a portion where the molten injection resin flowing in the mold joins and is welded, and occurs when there are a plurality of gates in the injection mold, or when pins, protrusions, ribs, and the like are present in the cavity.
In particular, when an injection molded article having a thin wall or a complicated shape is produced, there are many cases where a plurality of gates are present, and there are many cases where pins, protrusions, ribs, and the like are present in a cavity, and there are also many weld lines generated, and a decrease in strength and rigidity at the weld lines is a major problem.
In addition, there are cases where reinforcing fibers are filled in an injection resin for the purpose of high strength and high rigidity, and it is known that the fiber orientation of the reinforcing fibers is perpendicular to the flow direction of the injection resin at a weld line. Therefore, the reinforcing effect by the reinforcing fibers is hardly obtained at the weld line, and the strength and rigidity of the weld line are significantly lower than those of the portions other than the weld line. Since the strength and rigidity of the weld line are reduced, the strength and rigidity of the injection-molded article are also greatly reduced.
A technique for reinforcing a weld line to produce an injection-molded article having high strength and high rigidity is known.
Patent document 1 describes a method of reinforcing a weld line by inserting (insert) a thermoplastic resin film or sheet into an injection mold.
Patent document 2 describes a method of reinforcing a weld line by inserting a continuous fiber-reinforced thermoplastic resin composite material into an injection mold.
Disclosure of Invention
Problems to be solved by the invention
In the invention described in patent document 1, the thermoplastic resin film or sheet does not contain fibers, and a sufficient reinforcing effect cannot be obtained for reinforcing the weld line formed by the thermoplastic resin film or sheet only, and the strength and rigidity of the injection molded article are insufficient. Further, it is considered that, when only the thermoplastic resin film or sheet is inserted into the injection mold, the thermoplastic resin film or sheet is melted and flows in the injection molding, and thus it is difficult to ensure the uniformity of the thickness.
In the invention described in patent document 2, since a plain weave fabric of continuous fibers is used as the weld reinforcement base material, the characteristics of the base material are anisotropic. Therefore, the design is limited by considering the orientation of the reinforcing material with respect to the weld line. Further, when the weld lines are present in a plurality of directions, it is difficult to apply the weld lines to the respective directions. Further, since the reinforcing base material is formed of continuous fibers, a large difference in mechanical properties is generated from the injection molded body. Therefore, when a load is applied to the integrated molded body, stress is concentrated on the joint surface between the reinforcing base material and the injection molded body or the end portion of the reinforcing base material. Therefore, the stress concentration portion becomes a fracture point, and the strength of the integrated molded article is lowered. In addition, when the reinforcing base material including the thermoplastic resin is inserted into the injection mold, a part of the thermoplastic resin melts and flows, and thus it is difficult to ensure the uniformity of the thickness. In addition, the reinforcing base material may be buried in the injected resin.
In the invention described in
In the invention described in
The purpose of the present invention is to provide a molded body that solves the problem of injection molded body that the strength and rigidity at the weld line are reduced, and that can be applied to thin-wall molding or complex-shape molding.
Means for solving the problems
In order to solve the above problem, the present invention mainly has any one of the following configurations.
(1) An integrated molded article obtained by integrating a reinforcing base material (a) having discontinuous fibers (a1) and a resin (a2) with an injection-molded article (b) having discontinuous fibers (b1) and a resin (b2),
the reinforcing base material (a) is integrated with the injection-molded body (b) so as to cover a part or the whole of the weld line of the injection-molded body (b),
the ratio of the thickness Ta of the reinforcing base material (a) to the thickness T of the weld line portion of the integrated molded body satisfies the following relational expression:
in the case of Ea ≠ Ebw,
in the case of Ea Ebw,
Ta/T≤0.5，
ta: thickness of the reinforcing base Material (a)
T: thickness of weld line part of integrated molded body
Ea: flexural modulus of the reinforcing base Material (a) (widthwise of the weld line)
Ebw: the modulus of elasticity in bending (in the width direction of the weld line) of the weld line of the injection-molded article (b).
(2) An integrated molded article obtained by integrating a reinforcing base material (a) having discontinuous fibers (a1) and a resin (a2) with an injection-molded article (b) having discontinuous fibers (b1) and a resin (b2),
the thickness of the reinforcing base material (a) is 0.25mm or less,
the reinforcing base material (a) is integrated with the injection-molded body (b) so as to cover a part or all of the weld line of the injection-molded body (b).
(3) An integrated molded article obtained by integrating a reinforcing base material (a) having discontinuous fibers (a1) and a resin (a2) with an injection-molded article (b) having discontinuous fibers (b1) and a resin (b2),
the reinforcing base material (a) is integrated with the injection-molded body (b) so as to cover a part or the whole of the weld line of the injection-molded body (b),
when the integrated molded body is disposed so that the surface on which the reinforcing base material (a) is disposed faces upward in the horizontal direction and is projected from the upward direction, the reinforcing base material (a) has an area of 50% or less of the projected area of the integrated molded body,
the ratio Ea/Eb of the flexural modulus Ea of the reinforcing base material (a) to the flexural modulus Eb of the injection-molded body (b) in the non-weld line portion is 0.7 to 1.3.
Effects of the invention
According to the present invention, in reinforcing the weld line of the injection-molded article, it is not necessary to consider the arrangement direction of the reinforcing base material with respect to the weld line, and it is possible to prevent the fibers of the reinforcing base material from being disturbed at the time of integral molding and to prevent the reinforcing base material from being buried in the injection resin, and to realize the reinforcement of the weld line, and it is possible to obtain an integral molded article having a thin wall or a complicated shape. Further, according to the present invention, it is possible to obtain an integrated molded article in which stress is prevented from concentrating on the joint surface between the injection molded article and the reinforcing base material or the end portion of the reinforcing base material, and reinforcement of the weld line and strength as the integrated molded article are simultaneously achieved.
Drawings
FIG. 1 is a schematic view showing the range of a reinforcing base material in an integrated molded article in which a weld line portion is reinforced and the range in which the reinforcing base material is first embedded.
FIG. 2 is a schematic view showing a test piece cutting position in an integrated molded body in which a weld line portion is reinforced.
FIG. 3 is a schematic view of an integrated molded article obtained in example 18.
Fig. 4 is a schematic view of the integrated molded article obtained in example 20, in which the area of the reinforcing base material is 50% of the projected area of the integrated molded article in the plane in which the reinforcing base material is integrated.
Fig. 5 is a schematic view of the integrated molded article obtained in example 27, in which the area of the reinforcing base material is 30% of the projected area of the integrated molded article in the surface where the reinforcing base material is integrated.
FIG. 6 is a schematic view of a test piece and a tensile jig for evaluating the bonding strength.
FIG. 7 is a schematic view of a surface for measuring thickness variation of a reinforcing base material in an integrated molded body.
Detailed Description
The integrated molded article of the present invention is obtained by integrating a reinforcing base material (a) having discontinuous fibers (a1) and a resin (a2) with an injection-molded article (b) having discontinuous fibers (b1) and a resin (b2) so as to cover a part or all of the weld line of the injection-molded article. Here, "covering" means that the reinforcing base material (a) covers the weld line in the width direction of the weld line of the injection-molded article (b), and "part or all" of the weld line means part or all in the longitudinal direction. Preferred embodiments of the present invention will be described below.
The discontinuous fiber (a1) in the present invention is not particularly limited, and for example, carbon fiber, glass fiber, aramid fiber, alumina fiber, silicon carbide fiber, boron fiber, metal fiber, natural fiber, mineral fiber, and the like can be used, and 1 or 2 or more of the above can be used in combination. Among them, carbon fibers such as PAN-based, pitch-based, and rayon-based fibers are preferably used from the viewpoint of their high specific strength, high specific rigidity, and weight reduction effect. In addition, glass fibers are preferably used from the viewpoint of improving the economy of the obtained molded article, and carbon fibers and glass fibers are preferably used in combination particularly from the viewpoint of balance between mechanical properties and economy. In addition, aramid fibers are preferably used from the viewpoint of improving the impact absorbability and the shape-formability of the obtained molded article, and carbon fibers and aramid fibers are preferably used in combination particularly from the viewpoint of balance between mechanical properties and impact absorbability. In addition, from the viewpoint of improving the electrical conductivity of the obtained molded article, a reinforcing fiber coated with a metal such as nickel, copper, ytterbium, or the like may be used.
In addition, in the weld line in the injection-molded article, the orientation of the discontinuous fibers (b1) is perpendicular to the flow direction of the injection resin, and therefore, the electromagnetic wave shielding property at the weld line is lowered. From the viewpoint of electromagnetic wave shielding properties, the discontinuous fibers (a1) contained in the reinforcing base material (a) preferably exhibit electrical conductivity.
The discontinuous fibers (a1) in the present invention are preferably surface-treated with a sizing agent from the viewpoint of improving mechanical properties. Examples of the sizing agent include polyfunctional epoxy resins, acrylic polymers, polyols, and polyethyleneimines, and specifically include polyglycidyl ethers of aliphatic polyols such as glycerol triglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitol polyglycidyl ether, arabitol polyglycidyl ether, trimethylolpropane triglycidyl ether, and pentaerythritol polyglycidyl ether, polyacrylic acid, copolymers of acrylic acid and methacrylic acid, copolymers of acrylic acid and maleic acid, or mixtures of 2 or more of the foregoing, polyvinyl alcohol, glycerol, diglycerol, polyglycerol, sorbitol, arabitol, trimethylolpropane, pentaerythritol, and polyethyleneimines containing more amino groups in 1 molecule. Among them, glycerol triglycidyl ether, diglycerol polyglycidyl ether, and polyglycerol polyglycidyl ether are preferably used in the present invention, because 1 molecule of the polymer contains many highly reactive epoxy groups, has high water solubility, and is easily applied to the discontinuous fibers (a 1). The sizing agent is preferably contained in an amount of 0.01 to 5 parts by mass, more preferably 0.1 to 2 parts by mass, based on 100 parts by mass of the discontinuous fiber (a 1). In addition, as a preferable range, a combination of any one of the above upper limit values and any one of the lower limit values may be used. The sizing agent may be applied to the discontinuous fibers (a1) unevenly, and the portion selectively applied at a high concentration and the portion applied at a low concentration may be provided within the above-described preferable range.
Examples of means for applying the sizing agent to the discontinuous fibers (a1) include a method in which the discontinuous fibers (a1) are immersed in a liquid containing the sizing agent via a roll, and a method in which the sizing agent is atomized and blown onto the discontinuous fibers (a 1). In this case, in order to make the amount of the sizing agent attached to the discontinuous fibers (a1) more uniform, it is preferable to dilute the sizing agent with a solvent, or to control the temperature, the yarn tension, and the like at the time of application. Examples of the solvent for diluting the sizing agent include water, methanol, ethanol, dimethylformamide, dimethylacetamide, acetone, and the like, and water is preferable from the viewpoint of easiness of handling in the production process and disaster prevention. The solvent may be removed by heating to evaporate the sizing agent after it is imparted to the discontinuous fibers (a 1). When a compound insoluble or hardly soluble in water is used as the sizing agent, it is preferable to disperse the compound in water by adding an emulsifier or a surfactant. As the emulsifier or surfactant, an anionic emulsifier, a cationic emulsifier, a nonionic emulsifier, and the like can be used. Among them, the use of a nonionic emulsifier having a small interaction is preferable because the effect of the sizing agent is not easily suppressed.
The fiber length of the discontinuous fibers (a1) is not particularly limited, but is preferably 1 to 50mm, more preferably 3 to 30mm, from the viewpoint of enhancing the mechanical properties and moldability of the base material (a) and the integrated molded article. In addition, as a preferable range, a combination of any one of the above upper limit values and any one of the lower limit values may be used. When the fiber length of the discontinuous fibers (a1) is 1mm or more, the reinforcing effect of the discontinuous fibers (a1) can be effectively exhibited. When the diameter is 50mm or less, the dispersion of the discontinuous fibers (a1) can be maintained satisfactorily. The fiber length may be equal to all the discontinuous fibers (a1), or long fibers and short fibers may be mixed within the above-described preferred range.
As a method for measuring the fiber length of the discontinuous fibers (a1), for example, there is a method (dissolution method) in which only the resin of the reinforcing base material (a) is dissolved, and the remaining discontinuous fibers (a1) are separated by filtration and measured by microscopic observation. In the case where there is no solvent for dissolving the resin, there is a method (burning method) in which only the resin is burned out in a temperature range in which the discontinuous fiber (a1) is not oxidized and reduced in weight, the discontinuous fiber (a1) is separated, and measurement is performed by observation under a microscope. For the measurement, 400 discontinuous fibers (a1) were randomly selected, and the length thereof was measured by an optical microscope to a unit of 1 μm, and the fiber length and the ratio thereof were measured.
The weight ratio of the discontinuous fibers (a1) in the reinforcing base material (a) is preferably 5 to 60 mass%, more preferably 10 to 50 mass%, and still more preferably 15 to 40 mass% with respect to 100 mass% of the reinforcing base material (a) from the viewpoint of achieving both mechanical properties and moldability. In addition, as a preferable range, a combination of any one of the above upper limit values and any one of the lower limit values may be used.
In the present invention, the resin (a2) is not particularly limited, and is preferably a thermoplastic resin, for example. Specifically, thermoplastic resins selected from the following are mentioned: crystalline resins such as "fluorine-based resins such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN), polyesters such as liquid crystal polyesters, polyolefins such as Polyethylene (PE), polypropylene (PP), and polybutylene, polyarylene sulfides such as Polyoxymethylene (POM), Polyamide (PA), and Polyphenylene Sulfide (PPs), Polyketones (PK), Polyetherketones (PEK), Polyetheretherketones (PEEK), Polyetherketoneketones (PEKK), Polyethernitriles (PEN), and polytetrafluoroethylene"; non-crystalline resins such as Polycarbonate (PC), polymethyl methacrylate (PMMA), polyvinyl chloride (PVC), polyphenylene ether (PPE), Polyimide (PI), polyamide imide (PAI), polyether imide (PEI), Polysulfone (PSU), polyether sulfone, and Polyarylate (PAR)'; and phenol-based resins, phenoxy-based resins, and thermoplastic elastomers such as polystyrene-based, polyolefin-based, polyurethane-based, polyester-based, polyamide-based, polybutadiene-based, polyisoprene-based, fluorine-based resins, and acrylonitrile-based resins, copolymers thereof, and modified products thereof. Among them, from the viewpoint of lightweight of the obtained molded article, polyolefin is preferable, from the viewpoint of strength, polyamide is preferable, from the viewpoint of surface appearance, amorphous resins such as polycarbonate and styrene resin are preferable, from the viewpoint of heat resistance, polyarylene sulfide is preferable, from the viewpoint of continuous use temperature, polyether ether ketone is preferable, and from the viewpoint of chemical resistance, fluorine-based resins can be preferably used. As the resin (a2), a thermosetting resin can be used, and examples of the thermosetting resin include thermosetting resins selected from unsaturated polyesters, vinyl esters, epoxies, phenols, urea-melamines, polyimides, copolymers and modified products thereof, and the like.
In addition, the following may be added to the resin (a2) depending on the use thereof: mica, talc, kaolin, hydrotalcite, sericite, bentonite, xonotlite, sepiolite, smectite, montmorillonite, wollastonite, silica, calcium carbonate, glass beads, glass flakes, glass microspheres, clay, molybdenum disulfide, titanium oxide, zinc oxide, antimony oxide, calcium polyphosphate, graphite, barium sulfate, magnesium sulfate, zinc borate, calcium borate, aluminum borate whiskers, potassium titanate whiskers, and high molecular compounds, a metal-based, metal oxide-based, carbon black, graphite powder, and other conductivity-imparting materials, a brominated resin-and other halogen-based flame retardants, antimony trioxide, antimony pentoxide, and other antimony-based flame retardants, ammonium polyphosphate, aromatic phosphate, red phosphorus-and other phosphorus-based flame retardants, an organic acid metal salt, a carboxylic acid metal salt, an aromatic sulfonimide metal salt, and other organic acid metal salt-based flame retardants, zinc borate, zinc oxide, and zirconium compounds, and other inorganic flame retardants, inorganic, Nitrogen flame retardants such as cyanuric acid, isocyanuric acid, melamine cyanurate, melamine phosphate, and guanidine nitride, fluorine flame retardants such as PTFE, silicone flame retardants such as polyorganosiloxane, metal hydroxide flame retardants such as aluminum hydroxide and magnesium hydroxide, and other flame retardants, flame retardant auxiliaries such as cadmium oxide, zinc oxide, cuprous oxide, copper oxide, ferrous oxide, iron oxide, cobalt oxide, manganese oxide, molybdenum oxide, tin oxide, and titanium oxide, nucleating agents such as pigments, dyes, lubricants, mold release agents, compatibilizers, dispersants, mica, talc, and kaolin, plasticizers such as phosphate esters, heat stabilizers, antioxidants, color blocking agents, ultraviolet absorbers, flowability modifiers, foaming agents, antibacterial agents, vibration dampers, odor inhibitors, slip modifiers, and antistatic agents such as polyether ester amides. In particular, in the case of applications such as electric and electronic devices, automobiles, and aircrafts, flame retardancy is sometimes required, and it is preferable to add a phosphorus flame retardant, a nitrogen flame retardant, and an inorganic flame retardant.
The flame retardant is preferably 1 to 20 parts by mass per 100 parts by mass of the resin in order to exhibit a flame retardant effect and maintain a good balance of properties such as mechanical properties of the resin used and resin fluidity during molding. More preferably 1 to 15 parts by mass.
Next, the injection molded article (b) in the present invention is a molded article obtained by injection molding the discontinuous fiber (b1) and the resin (b 2).
The injection-molded article (b) contains the discontinuous fiber (b1) from the viewpoint of improving mechanical properties and heat resistance. The discontinuous fiber (b1) is not particularly limited, and examples thereof include discontinuous fibers generally used as reinforcing fibers, such as glass fibers, polyacrylonitrile-based, rayon-based, lignin-based, and pitch-based carbon fibers (including graphite fibers), potassium titanate whiskers, zinc oxide whiskers, calcium carbonate whiskers, wollastonite whiskers, aluminum borate whiskers, aramid fibers, alumina fibers, silicon carbide fibers, ceramic fibers, asbestos fibers, gypsum fibers, and metal fibers, and 2 or more kinds of fibers may be used in combination. Glass fibers are preferred from the viewpoint of material cost and mechanical properties, and carbon fibers are preferred from the viewpoint of lightweight and mechanical properties.
The resin (b2) in the present invention is not particularly limited, and the same thermoplastic resins as those exemplified for the resin (a2) can be exemplified, and from the viewpoints of moldability and mechanical properties, polyolefins, polyamides, polycarbonates, styrenic resins, polyarylene sulfides, polyether ether ketones, and fluorine-based resins are preferable, and polyolefins, polyamides, and polyarylene sulfides are particularly preferable.
In the present invention, the resin (b2) is preferably the same type of resin as the resin (a2) in view of integration with the reinforcing base material (a). Specific examples of the resin of the same type include polyamide resins, polyamides and copolyamides having a structure containing 50 mass% or more of
The mass ratio of the discontinuous fibers (b1) to the resin (b2) in the injection-molded article (b) is preferably 5 to 200 parts by mass, more preferably 10 to 100 parts by mass, and particularly preferably 20 to 60 parts by mass, based on 100 parts by mass of the resin (b2), from the viewpoint of balance between mechanical properties and moldability. In addition, as a preferable range, a combination of any one of the above upper limit values and any one of the lower limit values may be used. In the integrated molded article, the portion having a high mass ratio and the portion having a low mass ratio may be present within the above-described preferable ranges.
From the viewpoint of improving mechanical properties, the discontinuous fibers (b1) are preferably surface-treated with a sizing agent. Examples of the sizing agent include polyfunctional epoxy resins, acrylic polymers, polyols, and polyethyleneimines, and specifically include polyglycidyl ethers of aliphatic polyols such as glycerol triglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitol polyglycidyl ether, arabitol polyglycidyl ether, trimethylolpropane triglycidyl ether, and pentaerythritol polyglycidyl ether, polyacrylic acid, copolymers of acrylic acid and methacrylic acid, copolymers of acrylic acid and maleic acid, or mixtures of 2 or more of the foregoing, polyvinyl alcohol, glycerol, diglycerol, polyglycerol, sorbitol, arabitol, trimethylolpropane, pentaerythritol, and polyethyleneimines containing more amino groups in 1 molecule. Among them, glycerol triglycidyl ether, diglycerol polyglycidyl ether, and polyglycerol polyglycidyl ether are preferably used in the present invention, because 1 molecule of them contains many highly reactive epoxy groups, and they have high water solubility and are easily applied to the discontinuous fibers (b 1).
The sizing agent is preferably contained in an amount of 0.01 to 5 parts by mass, more preferably 0.1 to 2 parts by mass, based on 100 parts by mass of the discontinuous fiber (b 1). In addition, as a preferable range, a combination of any one of the above upper limit values and any one of the lower limit values may be used. The sizing agent may be applied unevenly to the discontinuous fibers (b1) and provided in a portion selectively applied at a high concentration and a portion applied at a low concentration within the above-described preferable range.
In the present invention, examples of means for applying the sizing agent to the discontinuous fibers (b1) include a method in which the discontinuous fibers (b1) are immersed in a liquid containing the sizing agent via a roll, a method in which the sizing agent is sprayed onto the discontinuous fibers (b1) in a mist form, and the like. In this case, in order to make the amount of the sizing agent attached to the discontinuous fibers (b1) more uniform, it is preferable to dilute the sizing agent with a solvent, or to control the temperature, the yarn tension, and the like at the time of application. Examples of the solvent for diluting the sizing agent include water, methanol, ethanol, dimethylformamide, dimethylacetamide, acetone, and the like, and water is preferable from the viewpoint of easiness of handling in the production process and disaster prevention. The solvent may be removed by heating to evaporate the sizing agent after it is imparted to the discontinuous fibers (b 1). When a compound insoluble or hardly soluble in water is used as the sizing agent, it is preferable to disperse the compound in water by adding an emulsifier or a surfactant. As the emulsifier or surfactant, an anionic emulsifier, a cationic emulsifier, a nonionic emulsifier, and the like can be used. Among them, the use of a nonionic emulsifier having a small interaction is preferable because the effect of the sizing agent is not easily suppressed.
The mass-average fiber length Lw of the discontinuous fibers (b1) is preferably 0.4mm or more from the viewpoint of improving the mechanical properties and dimensional accuracy of the injection-molded article (b). The longer the mass-average fiber length is, the higher the effect of improving strength and rigidity is, and particularly, the effect of remarkably improving impact strength can be obtained. The upper limit of the mass-average fiber length Lw of the discontinuous fibers (b1) is preferably 3.0mm or less, and a balance among strength, rigidity, and processability is improved by the mass-average fiber length Lw in this range. The mass-average fiber length Lw of the discontinuous fibers (b1) is more preferably 0.4mm to 1.0 mm. The discontinuous fibers (b1) may not all have the same length, but may have a distribution of different lengths. The mass-average fiber length Lw described above and the number-average fiber length Ln described below can be used to indicate that the discontinuous fibers (b1) have a distribution of different lengths.
The number average fiber length Ln of the discontinuous fibers (b1) is a simple average of the fiber length relative to the measured quantity, and can sensitively reflect the contribution of the fibers having a short fiber length. For the reinforcing effect based on the fiber length, the longer the fiber length is, the larger the reinforcing effect is. The effects of fibers with long fiber lengths and those with short fiber lengths differ and should not be classified as such. When importance is attached to the reinforcing effect achieved by the fiber having a long fiber length, the mass-average fiber length Lw can be considered.
Further, the distribution of the fiber length can be known by the ratio Lw/Ln of the mass average fiber length Lw to the number average fiber length Ln of the discontinuous fibers (b 1). When the value Lw/Ln is larger than 1, the fibers having a large fiber length are contained. The ratio Lw/Ln of the mass-average fiber length Lw to the number-average fiber length Ln of the discontinuous fibers (b1) is preferably 1.3 to 2.0.
In the present invention, the number average fiber length Ln of the discontinuous fibers (b1), the mass average fiber length Lw of the discontinuous fibers (b1), and the ratio Lw/Ln thereof can be determined by the following method. That is, a sample having a size of 10mm in length and 10mm in width was cut out from the injection-molded article (b) to prepare a test piece. The test piece was immersed in a solvent capable of dissolving the resin (b2) for 24 hours to dissolve the resin component. The test piece in which the resin component was dissolved was observed with a microscope at a magnification of 100 times. In this observation, the fiber length was measured for 400 arbitrary fibers in the visual field. The number average fiber length Ln and the mass average fiber length Lw were calculated based on the following formula, using the measured fiber length as Li.
Number average fiber length Ln ═ Sigma Li)/(N)
Mass mean fiber length Lw ═ Σ Li2)/(∑Li)
Wherein N is the number of the measurement roots (400).
The following may be added to the injection-molded article (b) depending on the use thereof: mica, talc, kaolin, hydrotalcite, sericite, bentonite, xonotlite, sepiolite, smectite, montmorillonite, wollastonite, silica, calcium carbonate, glass beads, glass flakes, glass microspheres, clay, molybdenum disulfide, titanium oxide, zinc oxide, antimony oxide, calcium polyphosphate, graphite, barium sulfate, magnesium sulfate, zinc borate, calcium borate, aluminum borate whiskers, potassium titanate whiskers, and high molecular compounds, a metal-based, metal oxide-based, carbon black, graphite powder, and other conductivity-imparting materials, a brominated resin-and other halogen-based flame retardants, antimony trioxide, antimony pentoxide, and other antimony-based flame retardants, ammonium polyphosphate, aromatic phosphate, red phosphorus-and other phosphorus-based flame retardants, an organic acid metal salt, a carboxylic acid metal salt, an aromatic sulfonimide metal salt, and other organic acid metal salt-based flame retardants, zinc borate, zinc oxide, and zirconium compounds, and other inorganic flame retardants, inorganic, Nitrogen flame retardants such as cyanuric acid, isocyanuric acid, melamine cyanurate, melamine phosphate, and guanidine nitride, fluorine flame retardants such as PTFE, silicone flame retardants such as polyorganosiloxane, metal hydroxide flame retardants such as aluminum hydroxide and magnesium hydroxide, and other flame retardants, flame retardant auxiliaries such as cadmium oxide, zinc oxide, cuprous oxide, copper oxide, ferrous oxide, iron oxide, cobalt oxide, manganese oxide, molybdenum oxide, tin oxide, and titanium oxide, nucleating agents such as pigments, dyes, lubricants, mold release agents, compatibilizers, dispersants, mica, talc, and kaolin, plasticizers such as phosphate esters, heat stabilizers, antioxidants, color blocking agents, ultraviolet absorbers, flowability modifiers, foaming agents, antibacterial agents, vibration dampers, odor inhibitors, slip modifiers, and antistatic agents such as polyether ester amides. In particular, in the case of applications such as electric and electronic devices, automobiles, and aircrafts, flame retardancy is sometimes required, and it is preferable to add a phosphorus flame retardant, a nitrogen flame retardant, and an inorganic flame retardant.
In the above-described integrated molded article of the present invention, the reinforcing base material (a) composed of the discontinuous fibers (a1) and the resin (a2) has the following structure from the viewpoint of the reinforcing effect on the weld line formed on the injection-molded article (b) and the moldability of the injection-molded article (b). That is, the ratio of the thickness Ta of the reinforcing base material (a) to the thickness T of the weld line portion of the integrated molded article composed of the reinforcing base material (a) and the injection-molded article (b) is set to a value (hereinafter, sometimes referred to as a neutral reinforcing base material ratio) obtained by the following equation expressed by using the flexural elastic modulus Ebw of the weld line of the injection-molded article (b) and the flexural elastic modulus Ea of the reinforcing base material (the direction orthogonal to the weld line, that is, the width direction of the weld line).
In the case of Ea ≠ Ebw,
in the case of Ea Ebw,
neutral reinforcing base material ratio of 0.5
Ea: flexural modulus of the reinforcing base Material (a) (widthwise of the weld line)
Ebw: flexural modulus of weld line of injection-molded article (b) (widthwise direction of weld line)
When Ta/T is larger than the neutral reinforcing base material ratio, the enhancement effect by increasing the thickness of the reinforcing base material is small, and the thickness of the reinforcing base material (a) is only increased meaningfully. Further, when the injection-molded article (b) and the reinforcing base material (a) are integrally molded, the resin fluidity at the weld line portion is insufficient, and a good molded article cannot be obtained. Thus, in the present invention, Ta/T is equal to or less than the neutral reinforcement base material ratio.
From the same viewpoint, Ta/T is preferably 0.9 or less of the neutral reinforcement base material ratio. On the other hand, Ta/T is preferably 0.05 or more of the neutral reinforcing base material ratio. When the thickness is less than 0.05 of the neutral reinforcing base material ratio, the effect of reinforcing the weld line portion from the reinforcing base material (a) tends to be small, and the physical properties of the weld line portion of the integrated molded article may be insufficient. More preferably 0.2 or more.
More specifically, the thickness of the reinforcing base material (a) in the present invention is preferably 0.25mm or less from the viewpoint of the workability of the reinforcing base material (a) and the moldability of the injection molded article (b). When the thickness is larger than 0.25mm, the flowability of the resin at the weld line portion may be insufficient when a molded article including the injection molded article (b) is integrally molded, and a good molded article may not be obtained. More preferably 0.2mm or less. On the other hand, the thickness of the reinforcing base material (a) is preferably 0.03mm or more. When the thickness is less than 0.03mm, the handling property of the reinforcing base material (a) is poor, and the reinforcing base material may be broken in the process of being inserted into the mold. More preferably 0.05mm or more.
The thickness of the reinforcing base material (a) was calculated as follows. 2 points X, Y are determined on the same plane of the reinforcing base material (a) so that the straight line distance XY is the longest, the thicknesses are measured at the respective divided points excluding both ends XY when the straight line XY10 is divided into equal parts, and the average value thereof is taken as the thickness of the reinforcing base material (a). The reinforcing base material usable in the present invention is considered to have no change in physical properties before and after integration, and therefore, the physical property values before integration may be used instead of the physical property values after integration.
The form of the reinforcing base material (a) is not limited, and examples thereof include sheet-like and tape-like forms, and a tape-like base material is preferable from the viewpoint of efficient arrangement along the weld line of the injection-molded article (b).
In the present invention, the thickness variation of the reinforcing base material (a) in the integrated molded article is preferably 10% or less. When the reinforcing base material is integrated with the injection-molded article, thickness variation occurs in the reinforcing base material (a), and when the thickness variation is more than 10%, the following may occur: when a load is applied to the integrated molded article, stress concentrates on the portion where the thickness changes, and as a result, the starting point of the breakage of the molded article is obtained. Preferably less than 5%. The lower limit of the thickness variation is not particularly limited, but is 0% if necessary. In addition, when the thickness variation is large and greater than 10%, stress tends to concentrate on a thin portion, and the following bonding strength between the reinforcing base material (a) and the injection molded article (b) may be insufficient.
The thickness variation was measured as follows. As shown in fig. 2, a portion in which the reinforcing base material and the injection molded body were integrated was cut out from the integrated molded body, embedded in an epoxy resin, and then polished so that the cut surface became the observation surface as shown in fig. 7, to prepare a test piece. The test piece was magnified 200 times by a laser microscope (for example, VK-9510 manufactured by KEYENCE corporation), and the thickness of the reinforcing base material was observed. An observation image was developed on a general-purpose image analysis software, and the average thickness t1, the maximum thickness t2, and the minimum thickness t3 of the reinforcing base material visible in the observation image were measured by a program incorporated in the software, and the thickness variation (%) of the reinforcing base material in the integrated molded article was calculated by the following formula. The average thickness t1 of the reinforcing base material was obtained by dividing the cross section of the reinforcing base material in the observation image into equal parts in the width direction 10, measuring the thickness at each divided point except for both ends, and the average value thereof was defined as the average thickness of the reinforcing base material.
Thickness deviation (%) ((t2(mm) -t3(mm))/t1 (mm))/100.
In the integrated molded article of the present invention, it is preferable that the reinforcing base material (a) is selected and disposed so as to satisfy the above-mentioned relationship, so that the ratio Ea/Eb of the flexural modulus of the reinforcing base material (a) to that of the injection molded article (b) in the non-weld line portion is 0.7 to 1.3. The ratio Ea/Eb of the flexural modulus of elasticity is 0.7 to 1.3, which means that stress is less likely to concentrate on the joining surface between the injection-molded article and the reinforcing base material or the end portion of the reinforcing base material, and a molded article can be obtained in which reinforcement of the weld line and strength of the integrated molded article are achieved at the same time. Preferably 0.8 to 1.2. In addition, as a preferable range, a combination of any one of the above upper limit values and any one of the lower limit values may be used. The bending modulus of the injection-molded article (b) may be constant over the entire non-weld-line portion, but may be high or low as long as the ratio of the bending moduli is within the above-described preferred range.
Specifically, the flexural modulus of the reinforcing base material (a) is preferably 10GPa or more. More preferably 15GPa or more. The lower limit of the flexural modulus is not particularly limited. When the flexural modulus of the reinforcing base material (a) is 10GPa or more, the deformation of the reinforcing base material due to the pressure of the injected resin when the reinforcing base material and the injection-molded article are integrated can be suppressed, and the twisting (よれ, japanese) and deformation of the integrated reinforcing base material are less likely to occur. When the flexural modulus of the reinforcing base material (a) is 15GPa or more, the reinforcing base material after integration is less likely to twist or deform even if the width of the reinforcing base material is small. In addition, when the flexural modulus of the reinforcing base material (a) is substantially isotropic, the reinforcing base material is preferably not easily twisted or deformed after the integration even when the injection resin pressure is applied to the reinforcing base material from any direction when the reinforcing base material and the injection molded body are integrated.
In the injection-molded article (b), the bending modulus of elasticity is preferably 10GPa or more in the non-weld-line portion. More preferably 15GPa or more, and still more preferably 20GPa or more. When the flexural modulus of the non-weld line portion of the injection molded article (b) is 10GPa or more, an integrated molded article having high rigidity can be obtained. The lower limit of the flexural modulus is not particularly limited.
The flexural modulus of the reinforcing base material (a) and the injection-molded article (b) was measured according to ISO178 method (1993). Each measured number n was 5, and the average value was defined as the flexural modulus of the reinforcing base material (a) and the injection-molded article (b). The ratio Ea/Eb of the flexural modulus is determined from the flexural moduli of the reinforcing base material (a) and the injection-molded article (b). The term "non-weld-line portion" refers to a portion of the injection molded article other than the weld line, and indicates a portion that can exhibit the original properties of the injection resin used.
When the ratio of the flexural modulus of the reinforcing base material (a) to that of the injection-molded article (b) in the non-weld-line portion is as described above, the projected area of the reinforcing base material (a) with respect to the integrated molded article is preferably 50% or less. That is, when the integrated molded body is disposed so that the surface on which the reinforcing base material (a) is disposed faces upward in the horizontal direction and is projected from the upper direction, the reinforcing base material (a) is preferably disposed within a range of 50% or less of the projected area of the integrated molded body. When the area ratio is 50% or less, the fluidity of the injection resin in the injection mold cavity is improved, and therefore, the thin-wall molding and the molding of a complicated shape are facilitated. Further, it is also excellent from the viewpoint of discharging air or decomposition gas of injected resin at the time of injection molding and reducing the weight of the molded article. The area ratio is more preferably 30% or less. From the viewpoint of weld reinforcement, the lower limit of the area of the reinforcing base material (a) is preferably 5% or more, and more preferably 10% or more, with respect to the projected area of the integrated molded body.
In view of moldability and weight reduction of the integrated molded article, when the area of the reinforcing base material is small, stress tends to concentrate on the joint surface between the injection molded article and the reinforcing base material or the end portion of the reinforcing base material in general, but by setting the ratio of the flexural modulus of elasticity of the reinforcing base material to that of the injection molded article in the non-weld line portion to the above, the concentration of stress can be suppressed, and moldability and strength of the integrated molded article can be simultaneously achieved.
In the integrated molded article of the present invention, the ratio σ a/σ b of the bending strength σ a of the reinforcing base material (a) to the bending strength σ b of the injection molded article (b) in the non-weld line portion is preferably 0.7 to 1.3. When the bending strength ratio σ a/σ b is 0.7 to 1.3, the weld line of the injection molded article is not excessively reinforced, and therefore, it is preferable from the viewpoint of cost reduction and weight reduction of the molded article. More preferably 0.8 to 1.2. In addition, as a preferable range, a combination of any one of the above upper limit values and any one of the lower limit values may be used. The bending strength of the injection-molded article (b) may be constant over the entire non-weld-line portion, but may be high and low as long as the ratio of the bending strengths is within the above-described preferable range.
Specifically, the reinforcing base (a) preferably has a flexural strength of 200MPa or more. More preferably 300MPa or more. Also in the injection molded article (b), the bending strength of the non-weld line portion is preferably 200MPa or more. More preferably 300MPa or more. The lower limit of the bending strength is not particularly limited. It is preferable that the bending strength of the injection-molded article (b) and the bending strength of the reinforcing base material (a) are both 200MPa or more, since the integrated molded article is not easily broken even when a load is applied thereto.
The flexural strength of the reinforcing base material (a) and the injection-molded article (b) was measured according to ISO178 method (1993). Each measured number n was 5, and the average value was defined as the flexural strength of the reinforcing base material (a) and the injection-molded article (b). The bending strength ratio σ a/σ b was determined from the bending strengths of the reinforcing base material (a) and the injection-molded article (b). In order to set the ratio of the bending strength of the reinforcing base material (a) to the bending strength of the injection-molded article (b) in the non-weld-line portion within the above range, the fiber content of each may be set to the same level, for example.
In the present invention, the reinforcing base material (a) is preferably substantially isotropic. The term "substantially isotropic" means that the flexural strength, flexural modulus, and linear expansion coefficient of the reinforcing base material (a) are equivalent regardless of the measurement direction. More specifically, the following is preferably indicated: test pieces were cut from the reinforcing base material (a) in 4 directions of 0 °, +45 °, -45 °, and 90 ° with any direction being the 0 ° direction, the flexural strength and flexural modulus were measured according to ISO178 method (1993) for each direction of the test piece, and the linear expansion coefficient was measured according to ISO11359-2(1999, TMA), and the maximum values thereof were 1.3 times or less the minimum values, that is, the flexural strength, flexural modulus, and linear expansion coefficient were uniform and did not depend on the direction. By making the reinforcing base material (a) substantially isotropic, the reinforcing base material can be integrally reinforced with the injection-molded article without considering the direction of the base material when reinforcing the weld line, and therefore, it is preferable. Further, even when the reinforcing base material is integrated with a thin and complex-shaped molded body at the time of injection molding, it is preferable that the reinforcing base material is prevented from being buried in the injection resin due to the disturbance of the fibers of the reinforcing base material caused by the molding pressure.
In order to make the reinforcing base material (a) substantially isotropic, the discontinuous fibers (a1) are preferably in a substantially monofilament-like state and are randomly dispersed. Here, the fact that the discontinuous fibers (a1) are substantially monofilament-like means that the discontinuous fibers (a1) are present in the form of fine fineness strands of less than 500. More preferably, the discontinuous fibers (a1) are dispersed in the form of filaments. The random dispersion means that the arithmetic average of the two-dimensional orientation angles of the discontinuous fibers in the cross-sectional observation image of the reinforcing base material (a) is in the range of 30 ° or more and 60 ° or less. The two-dimensional orientation angle refers to an angle formed by two discontinuous fibers (a) crossing each other, and is defined as: the angle formed by the crossing single fibers is an acute angle side angle in the range of 0 to 90 degrees.
The method for obtaining the reinforcing base material (a) in which the discontinuous fibers (a1) are randomly dispersed is not particularly limited, and examples thereof include (1) a method in which discontinuous fiber bundles having a chopped form are opened and dispersed by air jet, the dispersion is gathered on a conveyor belt, and the resultant product is impregnated with a resin and compounded, and then press-molded to obtain the reinforcing base material; (2) a method in which discontinuous fiber bundles having a chopped form and resin fibers are opened and mixed by air jet, the mixture is gathered on a conveyor belt, and the resulting product is pressure-molded to obtain the reinforcing base material; (3) a method in which discontinuous fibers having a short cut form are opened and dispersed in a dispersion liquid, paper is made on a support having holes, the resulting product is impregnated with a resin, and the resulting product is combined and pressure-molded to obtain the reinforcing base material; (4) a method in which a resin fiber and a discontinuous fiber bundle having a chopped form are opened and mixed in a dispersion, a sheet is made on a support having holes, and the resulting product is press-molded to obtain the reinforcing base material; (5) a method in which discontinuous fibers having a short cut form are opened and dispersed by a carding machine, the dispersion is gathered on a conveyor belt, the resulting product is impregnated with a resin, and the reinforcing base material is obtained by compounding and pressure molding; and (6) a method in which the discontinuous fiber bundles having a chopped form and the resin fibers are opened and mixed by a carding machine, the mixture is gathered on a conveyor belt, and the resultant is subjected to pressure molding to obtain the reinforcing base material. The methods (1) to (4) which are excellent in the opening property of the discontinuous fiber bundle and can maintain the fiber length of the discontinuous fiber at a relatively long level are more preferably used, and the method (3) or (4) is more preferably used from the viewpoint of productivity.
(1) In the method (2), the flow of the air stream is controlled to uniformly disperse the discontinuous fibers in a single fiber form, thereby improving the isotropy of the reinforcing base material (a). (3) In the method (4), the concentration of the discontinuous fibers with respect to the amount of the dispersion liquid is reduced, the stirring blade for stirring the dispersion liquid is formed into a shape having a large stirring force, or the number of revolutions of the stirring blade is increased, whereby the discontinuous fibers are uniformly dispersed in a single fiber form, and the isotropy of the reinforcing base material (a) can be improved.
The specific gravity of the reinforcing base material (a) is preferably 0.5 to 1.5 from the viewpoint of improving the lightweight property of the molded article. More preferably 0.5 to 1.3, and still more preferably 0.5 to 1.1. For the specific gravity measurement, the reinforcing base material (a) can be cut out and measured according to ISO1183 (1987).
Further, the linear expansion coefficient of the reinforcing base material (a) is preferably 7 × 10-6A value of less than or equal to K, more preferably 5X 10-6and/K is less than or equal to. The lower limit is not particularly limited. The linear expansion coefficient was measured in accordance with ISO11359-2 (1999). The reinforcing base material (a) has a linear expansion coefficient of 7X 10-6When the reinforcing base material is integrated with the injection-molded article, the reinforcing base material is prevented from being deformed, and the reinforcing base material is less likely to be twisted or deformed after the integration. Further, the reinforcing base material (a) has a linear expansion coefficient of 5X 10-6At a value of/K or less, the reinforcing base material is less likely to be integrated even if the width of the reinforcing base material is smallTorsion, deformation, etc. Further, it is more preferable that the reinforcing base material (a) has not only the linear expansion coefficient within the above range but also a substantially isotropic property.
The reinforcing base material (a) is preferably a band-shaped base material in terms of efficient arrangement along the weld line. The ribbon shape means a thin and elongated ribbon shape. Preferably, the thickness is 0.03 to 0.25mm and the width (width direction of the weld line) is 2.5 to 15 mm. The length is preferably 1.2 times or more, and more preferably 2 times or more, of the width of the reinforcing base material. The upper limit of the length of the reinforcing base material is not particularly limited. In addition, when the reinforcing base material is in the form of a thin strip, it has flexibility and excellent workability, and the reinforcing base material (a) can be inserted into an injection mold by an automatic Tape laying apparatus atl (automated Tape laying) or the like, which is preferable in view of productivity and coping with a complicated shape.
In the integrated molded article of the present invention, the bonding strength between the reinforcing base material (a) and the injection molded article (b) is preferably 7MPa or more. When the bonding strength is less than 7MPa, the effect of reinforcing the weld line is insufficient, and the integral molded article may not be satisfactory. More preferably 10MPa or more. The upper limit of the bonding strength is not particularly limited, and if necessary, the bonding strength is equal to the tensile strength of the resin used when the bonding interface is completely integrated, for example, 150MPa in the case of polyamide.
The bonding strength was measured as follows. First, as shown in fig. 2, a portion in which the reinforcing base material and the injection molded body were integrated was cut out as a test piece (fig. 6 (a)). Then, an adhesive (e.g., ThreeBond 1782, ThreeBond Co., Ltd.) was applied to a jig of the measuring apparatus shown in FIG. 6(b), and after leaving at 23. + -. 5 ℃ and 50. + -. 5% RH for 4 hours, the aforementioned test piece was adhered and fixed. Then, a tensile test was performed at an atmospheric temperature of 25 ℃. At this time, before the start of the test, the test piece was kept in a state where no load of the tensile test was applied for at least 5 minutes, and after the thermocouple was arranged on the test piece and the temperature was confirmed to be the same as the atmospheric temperature, the tensile test was performed. A tensile test was conducted by pulling the substrate at a tensile rate of 1.27 mm/min in a direction of 90 ℃ from the bonding surface of the substrate and the injection-molded article, and the maximum load (load at the time of starting separation of the reinforcing substrate and the injection-molded article, i.e., breaking load) was divided by the bonding area to obtain a value as the bonding strength (unit: MPa). The number of samples n is 5, and the average is used.
When the discontinuous fibers (b1) are contained in the injection-molded article (b), the physical properties of the weld line are generally likely to be remarkably reduced. Therefore, in the present invention, the reinforcing base material (a) is partially or entirely covered with the weld line of the injection molded article (b), and the reinforcing base material (a) and the injection molded article (b) are integrated. The method of integrating the reinforcing base material (a) and the injection-molded article (b) is not particularly limited, and examples thereof include a method of joining a previously molded reinforcing base material (a) and an injection-molded article (b), a method of arranging the reinforcing base material (a) in an injection-molding mold at the time of molding the injection-molded article (b) and integrating the same at the same time with the molding, and the like. Examples of the method for joining the reinforcing base material (a) and the injection molded article (b) include hot plate welding, vibration welding, ultrasonic welding, laser welding, automatic Tape laying apparatus atl (automated Tape laying), and the like, and the joining may be performed by an adhesive. In the method of simultaneous integration with injection molding, the reinforcing base material (a) may be disposed in a portion expected as a weld line in an injection mold and then integrated by injection molding. The method of disposing the reinforcing base material (a) in the injection molding mold is not particularly limited, and examples thereof include a method of inserting the reinforcing base material (a) cut into a weld line shape in advance, and a method of softening and melting the reinforcing base material (a) by heater heating, laser heating, or the like by an automatic tape laying apparatus ATL and attaching the reinforcing base material (a) in the mold. Among these, from the viewpoint of productivity and coping with complicated shapes, a method of attaching the reinforcing base material (a) into an injection mold by an automatic tape laying apparatus ATL and then performing injection molding to integrate the reinforcing base material (a) is preferable.
In the integrated molded article of the present invention, the reinforcing base material (a) is preferably integrated with the injection molded article within a distance of 2.5 to 15mm in the width direction of the weld line of the injection molded article (b). It is preferable that the weld line is integrated with the injection molded body within a distance of 2.5 to 15mm in the width direction, because weld reinforcement and weight reduction and moldability of the molded body can be achieved at the same time. More preferably 3 to 12.5mm, and still more preferably 5 to 10 mm. In addition, as a preferable range, a combination of any one of the above upper limit values and any one of the lower limit values may be used. In addition, there may be a portion integrated with a wide width and a portion integrated with a narrow width within the above-described preferable range.
Further, since the width of the weld line varies depending on the thickness of the integrated molded article, it is preferable that the reinforcing base material (a) is integrated with the injection molded article (b) so as to cover a part or all of the weld line while satisfying the following relationship in the width direction of the weld line of the injection molded article (b).
Wa: width of the reinforcing base material (a)
T: thickness of weld line part of integrated molded body
By satisfying the above relationship, reinforcement of the weld line and weight reduction and moldability of the molded article can be achieved at the same time, which is preferable. More preferably
The integrated molded article of the present invention has the advantages of injection molding, that is, the advantage of being able to mold a complicated molded article with good productivity, and is able to improve the strength and rigidity of a weld line, which is a problem of the injection molded article, and therefore, is useful for various applications such as automobile parts, aircraft parts, electric and electronic parts, office information equipment, building members, home electric appliances, medical equipment, various containers, daily necessities, and sanitary goods. Specific applications include automotive engine room (underbody) parts, automotive interior parts, automotive exterior parts, automotive connectors, electrical and electronic parts, building components, mechanical parts, containers, tableware, and the like.
Examples of the parts of the engine room for an automobile include an airflow meter, an air pump, a thermostat case, an engine frame, an ignition bobbin (ignition bobbin), an ignition case (ignition case), a clutch bobbin (clutch bobbin), a sensor case, an idle speed control valve, a vacuum switch valve, an ECU case, a vacuum pump case, an inhibitor switch (inhibitor switch), a rotation sensor, an acceleration sensor, a distributor cap (distributor cap), a coil base (coil base), an actuator case for ABS, a top and a bottom of a radiator tank, a cooling fan, a fan case (fan cowl), an engine cover, a cylinder cover, an engine oil pan, an oil filter, a fuel filter (fuel purifier), a distributor cap, a canister case (vapor canister), an air cleaner case, a synchromesh case, a brake booster part, cases (tubes), various tubes (cans), various kinds of canisters, and various kinds of canisters, Various hoses, various clamps, various valves, various pipes (pipe), etc.
Examples of the interior parts for automobiles include a torque lever, a belt member, a register blade (register), a washer lever (washer lever), a window regulator grip, a knob (knob) of the window regulator grip, an overtaking light lever, a sun visor holder, and various motor housings.
Examples of exterior parts for automobiles include roof side rails, fenders, garnishes (garnish), bumpers, mirror visors, spoilers, hood shutters, wheel covers, grille apron frames (grille apron covers), lamp reflectors, lamp bezels, and door handles.
Examples of the automotive connector include a harness connector, an SMJ connector, a PCB connector, and a door grommet connector (door grommet connector).
Examples of the electric and electronic components include relay boxes (relay boxes), coil bobbins, optical pickup chassis (optical pick-up housings), motor cases (motor cases), notebook computer housings and internal components, CRT display housings and internal components, printer housings and internal components, mobile terminals housings and internal components such as mobile phones, mobile personal computers, hand-held mobile devices (hand-held mobile), housings and internal components of recording medium (CD, DVD, PD, FDD, etc.) drives, housings and internal components of copiers, housings and internal components of facsimile machines, dish antennas, VTR components, television components, irons, compact discs, electric cooker components, microwave oven components, audio components, video device components such as cameras and projectors, video device components such as Compact Discs (CD), CD-ROMs, CD-R, CD-RWs, DVD-ROMs, and the like, A substrate for an optical recording medium such as a DVD-R, DVD-RW, a DVD-RAM, a blu-ray disc, a lighting component, a refrigerator component, an air conditioner component, a typewriter component, a word processor component, a housing for an electronic musical instrument, a home game machine, a portable game machine, or the like, an internal component, various gears, various housings (cases), a sensor, an LEP lamp, a connector, a socket, a resistor, a relay case (relay case), a switch, a coil bobbin, a capacitor, a variable capacitor housing, an optical head, a resonator, various terminal boards, a converter, a plug (plug), a printed wiring board, a tuner, a speaker, a microphone, an earphone, a small motor, a head base, a power module, a semiconductor, a liquid crystal, an FDD tray (FDD tray), an FDD chassis (FDDchassis), a motor brush holder, a transformer component, a coil bobbin, or the like.
Examples of the building member include a window pulley, a blind accessory (blind pipe), a pipe joint, a curtain liner (blind line), a blind component, a gas meter component, a water heater component, a sunroof panel, a heat insulating wall, a regulator, a plastic floor support, a ceiling hanger, a step, a door, and a floor.
Examples of the device parts include gears, screws, springs, bearings, levers (lever), key levers (key levers), cams (cam), ratchets, rollers, water supply parts, toy parts, bands, clips, fans, wires (japanese: テゲス), pipes, washing jigs, motor parts, microscopes, binoculars, cameras, clocks, and the like.
Examples of the containers and tableware include trays, blisters, knives, forks, spoons, tubes, plastic cans, soft bags (pouches), containers (containers), containers and tableware such as cans and baskets, hot fill (hot fill) containers, containers for microwave cooking, and containers for cosmetics.
Among them, the resin composition is particularly suitable for automotive interior parts, automotive exterior parts, automotive connectors, electric and electronic parts and electronic device cases which are required to be thin, lightweight and rigid.
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