阅读说明：本技术 包含氟树脂的组合物及该组合物和氟树脂分散液的制造方法 (Composition containing fluororesin, method for producing the composition and fluororesin dispersion ) 是由 E·陈 谢秀萍 增田祥 于 2019-03-22 设计创作，主要内容包括：一种组合物、一种该组合物的制造方法和一种从该组合物制造氟树脂分散液的方法,其中该组合物包含：(i)氟树脂,具有1μm或更大和5μm或更小的平均颗粒直径及10μm或更小的最大颗粒尺寸；(ii)分散剂；以及(iii)有机溶剂,其中该组合物中的有机溶剂的质量百分比为0.2％或更少。(A composition, a method for producing the composition, and a method for producing a fluororesin dispersion from the composition, wherein the composition comprises: (i) a fluororesin having an average particle diameter of 1 μm or more and 5 μm or less and a maximum particle size of 10 μm or less; (ii) a dispersant; and (iii) an organic solvent, wherein the mass percentage of the organic solvent in the composition is 0.2% or less.)

1. A composition, comprising:

(i) a fluororesin having an average particle diameter of 1 μm or more and 5 μm or less and a maximum particle size of 10 μm or less;

(ii) a dispersant; and

(iii) an organic solvent, wherein the mass percent of the organic solvent in the composition is 0.2% or less.

2. A composition according to claim 1, wherein the fluororesin is one or two selected from the group consisting of a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer and a tetrafluoroethylene-hexafluoropropylene copolymer.

3. A composition as set forth in claim 1 or 2 wherein said fluororesin comprises 10 mole (mol)% or less of a monomer.

4. The composition of claim 3 wherein the monomer is selected from the group consisting of itaconic anhydride and 5-norbornene-2,3-dicarboxylic anhydride.

5. The composition of any one of claims 1 to 4, wherein the dispersant is an oligomer.

6. The composition of claim 5, wherein the oligomer is hexafluoropropylene trimer.

7. The composition of any one of claims 1 to 6, wherein the organic solvent is selected from the group consisting of MEK (methyl ethyl ketone) and acetone.

8. The composition according to any one of claims 1 to 7, wherein the fluororesin composition is in the form of a powder or in the form of a cake-like material.

9. A method of making the composition of claim 1, the method comprising:

(i) a mixing step of mixing a fluororesin, a dispersant, an organic solvent and a dispersion aid to form a mixture;

(ii) a dispersion step of dispersing the fluororesin in the mixture to form a dispersion liquid;

(iii) a filtering step of removing the dispersion aid from the dispersion liquid; and

(iv) a drying step of removing the organic solvent in the filtered dispersion liquid so that the mass percentage of the organic solvent in the composition is 0.2% or less.

10. The method of claim 9, wherein the mixing step comprises:

(a) mixing the fluororesin, the dispersant and the organic solvent in the following parts by mass:

1 to 40 parts by mass of the fluororesin;

1 to 10 parts by mass of the dispersant; and

50 to 98 parts by mass of the organic solvent,

so that the total mass parts are 100;

(b) 10 to 20 parts by mass of the dispersion aid is added per 100 parts of the fluororesin, the dispersant and the organic solvent.

11. A method of manufacturing a fluororesin dispersion, the method comprising:

(i) a mixing step of mixing a second solvent to the fluororesin composition as defined in any one of claims 1 to 9 to form a mixture; and

(ii) a dispersing step of dispersing the fluororesin in the mixture without using a dispersing aid to form a fluororesin dispersion liquid,

wherein the fluororesin in the fluororesin dispersion liquid has an average particle diameter of 1 μm or more and 5 μm or less and a maximum particle size of 10 μm or less.

12. The method of claim 11, wherein the mixing step comprises:

adding 20 to 40 parts by mass of the fluororesin composition and 60 to 80 parts by mass of the second solvent so that the total parts by mass of the fluororesin composition and the second solvent amount to 100.

13. The method of claim 11 or 12, wherein the second solvent is selected from the group consisting of MEK (methyl ethyl ketone) and acetone.

Technical Field

The present invention relates to a composition containing a fluororesin, and a method for producing the composition and a fluororesin dispersion.

Background

Fluororesins are used as coatings because of their chemical resistance, heat resistance, low coefficient of friction, and electrical insulation properties. Specifically, the fluororesin is used as a coating layer in a high-frequency circuit board due to its excellent dielectric characteristics. In a conventional manufacturing process for manufacturing a high-frequency circuit board, a fluororesin is processed into fine particles which are dispersed in a dispersion medium containing a matrix resin and then laminated (laminated) with a conductor such as a copper foil and the like. Then, the resulting panel is further processed by etching and the like to form a high-frequency circuit board.

Since the matrix resin generally used in the above production process is soluble in a hydrocarbon solvent, the fluororesin must be first dispersed in the hydrocarbon solvent. However, since the interfacial tension is low, the fluororesin has poor wettability (wettability) to a hydrocarbon medium, and is difficult to disperse in the medium.

Further, considering that the fluororesin has a relatively high specific gravity, it is practically difficult to avoid separation (separation) in the fluororesin dispersion. Conventionally, it is necessary to carry out an industrial reaction (reaction) for maintaining a dispersion state by, for example, continuously stirring and setting a pot life (pot life) after dispersion.

This separation problem is particularly pronounced during transport. Another problem that may occur during the transportation of the fluororesin dispersion is that the organic solvent is generally difficult to handle, which not only increases the transportation cost, but also increases the transportation time.

Various methods for dispersion technology of fluororesin have been proposed.

JP-A-2017-193655 discloses ｃA fluororesin dispersion containing ｃA dispersant (thermally decomposable groups having ｃA specific oxyalkylene chain), fluororesin particles and water or an organic solvent.

JP-A-1987-121700 discloses ｃA fluororesin dispersion characterized by dispersing ｃA fluororesin powder having ｃA particle size of 2 μm or less in an organic solvent.

Japanese patent No. 2516241 discloses a technique of dispersing a fluororesin powder having a particle diameter of 2 μm or less in an aqueous medium in the presence of a nonionic surfactant and a thickener.

Japanese patent No. 4255169 discloses a dispersant having an organosiloxane structure, which uniformly disperses fiberized PTFE.

Japanese patent No. 5195425 discloses a technique of bringing a solution in which a fluororesin is substantially dispersed in an aqueous medium to an ion exchange resin, adding an electrolyte and an anionic emulsifier, and then performing phase separation and concentration to obtain an aqueous fluororesin solution.

JP-A-1998-176002 discloses ｃA technique in which polymer particles insoluble in an organic solvent are dispersed by ｃA polymer having an acrylic skeleton and having ｃA fluoroalkyl group in ｃA side chain.

US 2013/0149540 discloses a charging roller composition (charging roller composition) for improving the copy quality of a dry copying machine, and in the examples, discloses a technique of dispersing polytetrafluoroethylene (polytetrafluoroethylene) resin particles with a polymer having an acrylic skeleton and a fluoroalkyl group in a side chain.

WO 2018070420 discloses a composition obtained by mixing an aqueous fluoropolymer having specific sulfonic acid groups and carboxyl groups in its structure with water and subjecting the mixture to mesh filtration at a mesh size of 20 μm to obtain a composition having a degree of dispersion of 50%. Drying with a work amount (work amount) of 200W or less to obtain a powder is disclosed.

As described above, japanese patent No. 2516241 and japanese patent No. 5195425 disclose the use of water as a dispersion medium. However, since the latent heat of water evaporation is large, the use of water as a dispersion medium increases the time taken to apply the fluororesin coating to the substrate. Furthermore, the presence of a dispersing agent and a thickener for stabilizing the aqueous dispersion may cause the fluororesin to lose dielectric properties.

JP-A-1998-176002 and US 2013/0149540 disclose ｃA technique of producing ｃA non-aqueous dispersion by using ｃA polymer having an acrylic skeleton and having ｃA fluoroalkyl group in ｃA side chain. However, in the case where a non-fluorine moiety is present in the polymer, in the application to a high-frequency integrated circuit, it is likely that the properties possessed by the fluororesin may be disturbed.

WO 2018070420 discloses an ion exchange resin having a sulfonic group or a carboxyl group, which has a high affinity for water as a dispersion solvent itself but cannot be used in a high-frequency circuit board requiring electrical insulation. It also suggests the possibility of dispersing the ion exchange resin in organic solvents other than water, but no examples are shown.

Disclosure of Invention

According to an embodiment of the present invention, there are provided a composition containing a fluororesin, a method for producing the composition, and a method for producing a fluororesin dispersion as shown in the independent claims. Some optional features are defined in the dependent claims.

Drawings

Figure 1A illustrates the steps of forming a composition according to an embodiment of the present invention.

Fig. 1B shows a step of producing a fluororesin dispersion from the fluororesin composition of fig. 1A.

Detailed Description

Embodiments of the composition and the method for producing a fluororesin dispersion from the composition are described below.

Fig. 1A illustrates the steps of forming an embodiment of a composition 104 of the present invention. The composition 104 in this case is a fluororesin composition. In the present embodiment, the fluororesin composition 104 is a dry solid. The following ingredients were first mixed together in step 1: (a) fluororesin powder, (b) a dispersant, (c) a solvent, and (d) dispersing beads to form a mixture 101. In addition to the dispersing beads, other suitable dispersing aids may also be used. In step 2, which is regarded as a dispersion step, the fluororesin powder in the mixture 101 is dispersed by mechanical action. The dispersion by mechanical action may comprise shaking the mixture using a paint shaker. Thereafter, in step 3, the dispersed beads are filtered off by using a suitable filter 102 (in the examples described in the following examples section, see examples of such filters) to form a first fluororesin dispersion liquid 106. Finally, in step 4, the first fluororesin dispersion 106 is dried to form the dry solid fluororesin composition 104 of the present example.

The drying process of step 4 may be a continuous drying process with checkpoints during the process to confirm that the mass percent of organic solvent in the composition 104 is 0.2% or less. In another embodiment, the drying process may be one in which the first fluororesin dispersion 106 is subjected to more than one drying at the same temperature or a fluctuating temperature, and in which there is a stopping point or a check point between the more than one drying to confirm that the mass percentage of the organic solvent in the composition 104 is 0.2% or less. A percentage of solvent of 0.2% or less ensures that the composition 104 is sufficiently dry. The confirmation step at each stopping or inspection point to ensure that the mass percent of solvent in the composition 104 is 0.2% or less may be to subject the composition 104 to a heating process and determine the mass of the composition 104 before and after the heating process to verify the form of the composition 104 with a mass percent change of 0.2% or less. After the drying process, the percent change in mass of the composition 104 was found to be 0.2% or less, and it can be concluded that the percent mass of the solvent in the composition 104 was 0.2% or less.

In the embodiment of forming composition 104 shown in fig. 1A, the ingredients are added in step 1 in the following parts by mass (part per mass):

1 to 40 parts by mass of a fluororesin;

1 to 10 parts by mass of a dispersant; and

50 to 98 parts by mass of a first organic solvent,

so that the total parts by mass of the ingredients amount to 100.

Then, 10 to 20 parts by mass of the dispersion beads are added per 100 parts of the mixture of the fluororesin, the dispersant and the first organic solvent.

Fig. 1B shows a step of producing a second fluorine resin dispersion liquid from the dried solid fluororesin composition 104 produced in the embodiment of fig. 1A. In step a, a second solvent 204 is first added to the dry solid fluororesin composition 104 of fig. 1A to form a mixture 201. In step B, the mixture 201 is subjected to a redispersion step by a mechanical action to redisperse the fluororesin in the mixture 201 to form a second fluororesin dispersion liquid 202.

In the embodiment of making the second dispersion 202 shown in fig. 1B, the ingredients are added in step a in the following parts by mass:

20 to 40 parts by mass of the composition 104; and

60 to 80 parts by mass of a second organic solvent,

so that the total parts by mass of the composition and the second organic solvent total 100.

The composition 104 of fig. 1A refers to one in which the composition comprises a fluororesin having an average particle diameter of 1 μm or more and 5 μm or less and a maximum particle size of 10 μm or less, a dispersant, and an organic solvent or a residual organic solvent having a mass percentage of 0.2 mass% or less. The composition 104 of fig. 1A may be in the form of a cake-like material, or more specifically, a dried or hardened solid. In another embodiment, the composition 104 of fig. 1A may be in powder form and does not aggregate to form a cake-like material.

One of the advantages of the composition 104 of fig. 1A is that shipping problems can be avoided because the hazardous organic solvents in the fluororesin dispersion are removed or substantially removed.

Another advantage of the composition 104 of fig. 1A is that it can be easily returned to the dispersed state again by steps a and B of fig. 1B. The size of the fluororesin powder after redispersion in step B of fig. 1B is 10 μm or less. Yet another advantage is that the redispersion of the composition 104 in step a is performed without the use of dispersing beads. Furthermore, a suitable but different (different from the first organic solvent) solvent may be used in step a of fig. 1B. The organic solvent used for redispersion of the composition 104 is not limited to the first organic solvent.

One of the applications of the composition according to an embodiment of the present invention is for the manufacture of high frequency circuit boards. Thus, the fluororesin in the composition 104 of fig. 1A may be a perfluoro (perfluoro) type fluororesin having higher dielectric characteristics. Specifically, the fluororesin may be a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer). Tetrafluoroethylene-hexafluoropropylene (tetrafluoroethylene-hexafluoropropylene) is another choice for the fluororesin because it melts during the heating process. Accordingly, the fluororesin may be one or two selected from the group consisting of a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer and a tetrafluoroethylene-hexafluoropropylene copolymer.

In another embodiment of the present invention, the fluororesin in the composition 104 of fig. 1A may contain 10 mol% or less of a monomer in order to improve the function of the high-frequency circuit board. For example, the fluororesin may contain itaconic anhydride (itaconic anhydride) and 5-norbornene-2,3-dicarboxylic anhydride (5-norbornene-2,3-dicarboxylic anhydride) to improve the adhesion of the matrix resin to the substrate of such a high frequency circuit board.

According to an embodiment of the present invention, the size of the fluororesin powder in the second fluorine resin dispersion 202 of fig. 1B (after redispersion) is 10 μm or less. When it is 10 μm or more, there may be some negative effects on the smoothness of the substrate of the high-frequency circuit board, and the dielectric characteristics of the substrate may be affected. This in turn may affect the performance of the high frequency circuit. Particularly in a multilayer board in which a plurality of substrates are laminated together, such a problem that affects the performance of a high-frequency circuit becomes remarkable. In order to obtain a redispersed state of not more than 10 μm, it is required that the average particle diameter in the composition 104 of fig. 1A is 1 to 5 μm or less, and the maximum particle diameter is 10 μm or less. When the average particle diameter is 1 μm to 5 μm, the amounts of the dispersant and the organic solvent used for the redispersed second fluorine resin dispersion liquid 202 do not adversely affect the electrical characteristics.

With respect to the organic solvent used for the first fluororesin dispersion 106 of fig. 1A, one embodiment is to volatilize the organic solvent at normal pressure or reduced pressure until the mass percentage of the organic solvent in the composition 104 is 0.2% or less. In the case of application to high-frequency circuit boards, organic solvents are generally used based on solubility in a matrix resin. Illustrative examples of such organic solvents include MEK (methyl ethyl ketone), toluene (toluene), xylene (xylene), DMF (dimethylformamide), NMP (N-methylpyrrolidinone), DMAC (dimethylacetamide), CAN (cyclohexanone), and the like. As to the dispersant in the composition 104 of FIG. 1A, one embodiment is an oligomer of hexafluoropropylene (hexafluropropene). Thus, the dispersant may be a hexafluoropropylene trimer (hexafluoropropylene trimer). The dispersant may comprise one or more surfactants. The amount of the dispersant added varies depending on the organic solvent used, but about 1 to 10 parts by mass of the dispersant can be generally added per 100 parts of the fluororesin.

As the dispersion beads for dispersing the first fluororesin dispersion liquid 106 of fig. 1A, glass, ceramic beads and oxide beads may be used.

Examples

Preparation of the Dispersion in example 1(Ex.1)

25g of tetrafluoroethylene-perfluoroalkyl ether copolymer (tetrafluoroethylene-perfluoroalkyl ether copolymer) (particle diameter D50: 2.1 μm) (fluororesin), 1g of hexafluoropropylene trimer surfactant (dispersant), 75g of Methyl Ethyl Ketone (MEK) solvent (organic solvent), and 12.5g of zirconium dioxide (Zr) beads (diameter 2mm) as dispersing beads were added to a glass jar of 300mL capacity. The glass jar was sealed with an inner lid and jar lid. The sealed glass jar was placed in a paint shaker (Collomix AGIA 200) and shaken for 60 minutes. The mixture in the tank was then filtered once through a 185 micron screen (an example of filter 102 of fig. 1A) to remove the zirconia beads. The particle size of the obtained dispersion was determined to be less than 10 μm by a mill.

Examples2(Ex.2) preparation of the Dispersion

Dispersions were prepared as described in example 1, except that acetone was used as the organic solvent instead of MEK. The particle size of the obtained dispersion was determined to be less than 10 μm by a mill.

Preparation of the Dispersion in example 3(Ex.3)

This example is intended as a comparative example. A dispersion was prepared as described in example 1, except that zirconia beads were not added as dispersion beads. The particle size of the obtained dispersion was determined to be greater than 10 μm by means of a mill.

Preparation of the Dispersion in example 4(Ex.4)

This example is intended as a comparative example. The dispersion was prepared as described in example 1, except that the shaking time was 45 minutes instead of 60 minutes. The particle size of the obtained dispersion was determined to be greater than 10 μm by means of a mill.

Table 1 shows a summary of the results of examples 1 to 4. The desired results (i.e., particle size less than 10 μm) were found in examples 1 and 2, while examples 3 and 4 are comparative examples that did not produce the desired results.

Table 1, summary of the results of examples 1 to 4

Preparation of the redispersion in example I

The dispersion obtained in example 1 above was dried by exposing it to ambient conditions (25 ℃) for 7 days and the glass jar was unsealed in a fume hood to obtain a cake-like material. The cake material was confirmed to have been dried by heating the cake material and verifying that the mass change percentage of the cake material was 0.2% or less. 20g of the cake material and 60g of acetone were added to a glass jar of 300mL capacity. The mass ratio of the redispersion solvent to the cake material is 3: 1. the glass jar was sealed with an inner lid and jar lid. The sealed glass jar was placed in a paint shaker (Collomix AGIA 200) and shaken for 60 minutes. The particle size of the obtained dispersion was determined to be less than 10 μm by a mill.

Preparation of the redispersion in example II

A redispersion was prepared as described in example I, except MEK was used as the redispersion solvent. The particle size of the obtained dispersion was determined to be less than 10 μm by a mill.

Preparation of the redispersion in example III

A redispersion was prepared as described in example I, except that the cake material used was obtained by drying from example 2 and MEK was used as the redispersing solvent. The particle size of the obtained dispersion was determined to be less than 10 μm by a mill.

Preparation of the redispersion from example IV

This example is intended as a comparative example. A redispersion was prepared as described in example I, except that dimethylacetamide was used as the redispersion solvent. The particle size of the obtained dispersion was determined to be greater than 10 μm by means of a mill.

Preparation of the redispersion in example V

This example is intended as a comparative example. A redispersion was prepared as described in example I, except that toluene was used as the redispersion solvent. The particle size of the obtained dispersion was determined to be greater than 10 μm by means of a mill.

Preparation of the redispersion from example VI

This example is intended as a comparative example. Except that toluene was used as the redispersing solvent and the mass ratio of the mass of redispersing solvent to the mass of "cake material" was increased to 4: 1, redispersions were prepared as described in example I. The particle size of the obtained dispersion was determined to be greater than 10 μm by means of a mill.

Preparation of the redispersion in example VII

This example is intended as a comparative example. Redispersion was prepared as described in example I, except that toluene was used as redispersion solvent and the redispersion method used was stirring for 60 minutes by means of a paint stirrer. The particle size of the obtained dispersion was determined to be greater than 10 μm by means of a mill.

Table 2 below shows the successful redispersion results by using a redispersing solvent different from the first dispersing solvent. Successful results were defined as redispersion to particle sizes below 10 μm. Successful redispersion examples were found in examples I and III, while examples II and IV to VII are comparative examples.

TABLE 2 summary of the results of examples I to VII

[ details of the chemicals used ]

In the specification and claims, unless the context clearly dictates otherwise, the term "comprising" has a non-exclusive meaning in the sense of "including at least" and not an exclusive meaning in the sense of "consisting only of. The same logic applies to other forms of grammatical variations of words such as "includes", "including", etc.

While the invention has been described in connection with several examples and embodiments, the invention is not so limited, but covers various obvious modifications and equivalent arrangements, which fall within the purview of the appended claims. Although features of the invention are expressed in certain combinations among the claims, it is contemplated that these features can be arranged in any combination and order.