阅读说明：本技术 含氟弹性共聚物组合物、氟橡胶及其制造方法 (Fluorine-containing elastic copolymer composition, fluororubber, and method for producing same ) 是由 安田智子 河合刚 目黑敏幸 米田利一 弗里茨·西蒙 巨势丈裕 于 2020-04-01 设计创作，主要内容包括：提供无需炭黑等添加剂也具有能够用于密封材料等的硬度的含氟弹性共聚物组合物、氟橡胶及其制造方法。一种含氟弹性共聚物组合物的制造方法,其中,将含氟弹性共聚物水分散液与氟树脂水分散液混合而得到相对于含氟弹性共聚物100质量份包含氟树脂0.5～20质量份的水分散液混合物之后,使该水分散液混合物聚集,所述制造方法满足下述条件1和条件2中的至少一者：条件1：上述含氟弹性共聚物水分散液的pH值与上述氟树脂水分散液的pH值之差的绝对值为2.0以下。条件2：上述含氟弹性共聚物水分散液的pH值与上述氟树脂水分散液的pH值均为7.0以上。(Provided are a fluorine-containing elastic copolymer composition having hardness usable for sealing materials and the like without requiring additives such as carbon black, a fluororubber, and a method for producing the same. A process for producing a fluorinated elastic copolymer composition, which comprises mixing an aqueous dispersion of a fluorinated elastic copolymer with an aqueous dispersion of a fluororesin to obtain an aqueous dispersion mixture containing 0.5 to 20 parts by mass of the fluororesin per 100 parts by mass of the fluorinated elastic copolymer, and then aggregating the aqueous dispersion mixture, wherein the process satisfies at least one of the following conditions 1 and 2: condition 1: the absolute value of the difference between the pH of the aqueous dispersion of the elastic fluorocopolymer and the pH of the aqueous dispersion of the fluororesin is 2.0 or less. Condition 2: the pH value of the aqueous dispersion of the elastic fluorocopolymer and the pH value of the aqueous dispersion of the fluororesin are both 7.0 or more.)

1. A process for producing a fluorinated elastic copolymer composition, which comprises mixing an aqueous dispersion of a fluorinated elastic copolymer with an aqueous dispersion of a fluororesin to obtain an aqueous dispersion mixture containing 0.5 to 20 parts by mass of the fluororesin per 100 parts by mass of the fluorinated elastic copolymer, and then aggregating the aqueous dispersion mixture,

the manufacturing method satisfies at least one of the following conditions 1 and 2:

condition 1: the absolute value of the difference between the pH value of the aqueous dispersion of the elastic fluorocopolymer and the pH value of the aqueous dispersion of the fluororesin is 2.0 or less,

condition 2: the pH value of the aqueous dispersion of the elastic fluorocopolymer and the pH value of the aqueous dispersion of the fluororesin are both 7.0 or more.

2. The method for producing a fluorinated elastic copolymer composition according to claim 1, wherein the fluorinated elastic copolymer is a copolymer having a tetrafluoroethylene-based unit and a propylene-based unit.

3. The method for producing a fluorinated elastic copolymer composition according to claim 1 or 2, wherein the fluororesin is polytetrafluoroethylene.

4. The method for producing the elastic fluorocopolymer composition according to any one of claims 1 to 3, wherein the elastic fluorocopolymer in the aqueous elastic fluorocopolymer dispersion has a cumulative 50% particle diameter on a volume basis of 30 to 200 nm.

5. The method for producing a fluorinated elastic copolymer composition according to any one of claims 1 to 3, wherein the fluororesin aqueous dispersion contains a fluororesin having a volume-based cumulative 50% particle diameter of 200 to 400 nm.

6. The method for producing an elastic fluorocopolymer composition according to any one of claims 1 to 5, wherein the aggregation is performed by adding a coagulant to the aqueous dispersion mixture.

7. The method for producing a fluorinated elastic copolymer composition according to any one of claims 1 to 5, wherein the aggregation is performed by freezing the aqueous dispersion mixture.

8. A fluorine-containing elastic copolymer composition comprising a fluorine-containing elastic copolymer and a fluororesin, wherein the fluorine-containing elastic copolymer comprises 100 parts by mass of the fluorine-containing elastic copolymer 0.5 to 20 parts by mass of the fluororesin, the fluororesin is dispersed in the fluorine-containing elastic copolymer, and the average dispersed particle size of the fluororesin is 30 to 200 nm.

9. The fluoroelastomer copolymer composition of claim 8, wherein the fluoroelastomer copolymer is a copolymer having tetrafluoroethylene-based units and propylene-based units.

10. The fluoroelastomer copolymer composition according to claim 8 or 9, wherein the fluororesin is polytetrafluoroethylene.

11. A process for producing a fluororubber, which comprises adding a crosslinking agent to the fluorine-containing elastic copolymer composition obtained by the process according to any one of claims 1 to 7 and crosslinking the resulting mixture.

12. A fluororubber obtained by crosslinking the fluorine-containing elastic copolymer composition according to any one of claims 8 to 10.

13. The fluororubber according to claim 12, wherein the fluororesin is dispersed in the fluororubber in a proportion of 0.5 to 20 parts by mass relative to 100 parts by mass of the component derived from the fluorine-containing elastic copolymer, and the fluororesin has an average dispersed particle diameter of 30 to 200 nm.

Technical Field

The present invention relates to a fluorine-containing elastic copolymer composition containing a fluorine-containing elastic copolymer and a fluororesin, a fluororubber composition, and a method for producing the same.

Background

Crosslinked rubbers obtained by crosslinking a fluorinated elastic copolymer (so-called fluororubbers) are excellent in heat resistance, chemical resistance, oil resistance, weather resistance, and the like, and are widely used as sealing materials (e.g., O-rings, gaskets, oil seals, and gaskets) and cushioning materials in the fields of vehicles, ships, aircraft, general-purpose machines, buildings, and the like.

As a method for producing such a crosslinked rubber, patent document 1 discloses the following method: a composition containing a fluorinated elastic copolymer having a tetrafluoroethylene-based unit and a propylene-based unit, an organic peroxide (crosslinking agent), a crosslinking assistant, and the like is crosslinked to obtain a crosslinked rubber.

Documents of the prior art

Patent document

Patent document 1 International publication No. 2009/119202

Disclosure of Invention

Problems to be solved by the invention

Such a crosslinked rubber is usually subjected to an operation of adding carbon black or the like to obtain a necessary hardness. However, for example, when the sealing material is used in a semiconductor manufacturing apparatus, the additive may affect the semiconductor product.

The invention provides a fluororubber having hardness usable for sealing materials and the like without additives such as carbon black, a fluorine-containing elastic copolymer composition from which the fluororubber is easily obtained, and a method for producing the same.

Means for solving the problems

The present inventors have conducted intensive studies on the above-mentioned problems, and as a result, have found that a fluorinated elastic copolymer composition capable of giving a fluororubber having high hardness can be easily obtained by mixing and aggregating an aqueous dispersion of a fluorinated elastic copolymer and an aqueous dispersion of a fluororesin, and have completed the present invention.

That is, the inventors have found that the above problems can be solved by the following configuration.

[1] A process for producing a fluorinated elastic copolymer composition, which comprises mixing an aqueous dispersion of a fluorinated elastic copolymer with an aqueous dispersion of a fluororesin to obtain an aqueous dispersion mixture containing 0.5 to 20 parts by mass of the fluororesin per 100 parts by mass of the fluorinated elastic copolymer, and then aggregating the aqueous dispersion mixture.

The manufacturing method satisfies at least one of the following conditions 1 and 2:

condition 1: the absolute value of the difference between the pH of the aqueous dispersion of the elastic fluorocopolymer and the pH of the aqueous dispersion of the fluororesin is 2.0 or less.

Condition 2: the pH value of the aqueous dispersion of the elastic fluorocopolymer and the pH value of the aqueous dispersion of the fluororesin are both 7.0 or more.

[2] The process for producing a fluorinated elastic copolymer composition according to [1], wherein the fluorinated elastic copolymer is a copolymer having a tetrafluoroethylene-based unit and a propylene-based unit.

[3] The process for producing a fluorinated elastic copolymer composition according to [1] or [2], wherein the fluororesin is polytetrafluoroethylene.

[4] The process for producing a fluorinated elastic copolymer composition according to any one of [1] to [3], wherein the fluorinated elastic copolymer contained in the aqueous fluorinated elastic copolymer dispersion has a volume-based cumulative 50% particle diameter of 30 to 200 nm.

[5] The process for producing a fluorinated elastic copolymer composition according to any one of [1] to [3], wherein the fluororesin contained in the aqueous fluororesin dispersion has a volume-based cumulative 50% particle diameter of 200 to 400 nm.

[6] The process for producing a fluorinated elastic copolymer composition according to any one of [1] to [5], wherein the aggregation is carried out by adding a coagulant (coagulant) to the aqueous dispersion mixture.

[7] The process for producing a fluorinated elastic copolymer composition according to any one of [1] to [5], wherein the aggregation is carried out by freezing the aqueous dispersion mixture.

[8] A fluorine-containing elastic copolymer composition comprising a fluorine-containing elastic copolymer and a fluororesin, wherein the fluorine-containing elastic copolymer comprises 100 parts by mass of the fluorine-containing elastic copolymer 0.5 to 20 parts by mass of the fluororesin, the fluororesin is dispersed in the fluorine-containing elastic copolymer, and the average dispersed particle size of the fluororesin is 30 to 200 nm.

[9] The fluoroelastic copolymer composition according to [8], wherein the fluoroelastic copolymer is a copolymer having a tetrafluoroethylene-based unit and a propylene-based unit.

[10] The fluorine-containing elastic copolymer composition according to [8] or [9], wherein the fluororesin is polytetrafluoroethylene.

[11] A process for producing a fluororubber, which comprises adding a crosslinking agent to the fluorine-containing elastic copolymer composition obtained by the process according to any one of [1] to [7] to crosslink the composition.

[12] A fluororubber obtained by crosslinking the fluorine-containing elastic copolymer composition according to any one of [8] to [10 ].

[13] The fluororubber according to [12], wherein the fluororesin is contained in an amount of 0.5 to 20 parts by mass per 100 parts by mass of the component derived from the elastic fluorocopolymer, the fluororesin is dispersed in the fluororubber, and the average dispersed particle diameter of the fluororesin is 30 to 200 nm.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, there can be provided a fluororubber excellent in hardness without requiring an additive such as carbon black, a fluorine-containing elastic copolymer composition from which the fluororubber can be easily obtained, and a method for producing the same.

Detailed Description

The meaning of the terms in the present invention is as follows.

The "unit" is a general term for a radical derived from 1 molecule of the monomer directly formed by polymerizing the monomer and a radical obtained by chemically converting a part of the radical. The "monomer-based unit" is hereinafter also simply referred to as "unit".

The numerical range represented by "to" represents a range including numerical values before and after "to" as a lower limit value and an upper limit value.

"rubber" means a rubber exhibiting the properties defined in JIS K6200 (2008), and is distinguished from "resin".

"volume-based cumulative 50% particle size" means: the particle size distribution was measured by a laser diffraction scattering method, and a cumulative curve was obtained with the total volume of all particles being 100%, and the particle size of a point on the cumulative curve where the cumulative volume reached 50%. Hereinafter also referred to as D50.

In the process for producing the elastic fluorocopolymer composition of the present invention, as the elastic fluorocopolymer to be contained in the aqueous elastic fluorocopolymer dispersion, preferred are: a copolymer having a unit based on tetrafluoroethylene (hereinafter also referred to as TFE.) and a unit based on propylene, a copolymer having a unit based on TFE and a unit based on perfluoro (alkyl vinyl ether) (hereinafter also referred to as PAVE.), or a copolymer having a unit based on hexafluoropropylene (hereinafter also referred to as HFP.) and a unit based on vinylidene fluoride (hereinafter also referred to as VdF.).

The elastic fluorocopolymer of the present invention is a copolymer having no observed melting point, unlike a resin. More precisely, copolymers in which the melting point is not visible due to a thermal decomposition temperature lower than the melting point.

The elastic fluorocopolymer of the present invention is a copolymer capable of being crosslinked. More specifically, it is a copolymer having a crosslinking point, and a rubber is obtained by adding a crosslinking agent or the like and then crosslinking the copolymer.

The storage modulus G' of the elastic fluorocopolymer of the invention is preferably 10 to 800kPa, more preferably 150 to 600kPa, and still more preferably 200 to 500 kPa.

Each copolymer can be obtained by a conventional radical polymerization method. Examples of the radical polymerization method include: living radical polymerization methods such as iodine transfer polymerization methods in which radical polymerization is carried out in the presence of iodine or an iodine compound.

Examples of the copolymer having a TFE unit and a propylene unit (hereinafter also referred to as a P unit) and the production method thereof include copolymers described in international publication No. 2009/119202 and international publication No. 2017/057512.

Examples of the copolymer having HFP units and VdF units and the process for producing the same include the copolymers described in Japanese patent application laid-open No. H06-306180.

Examples of the copolymer having a TFE unit and a PAVE unit and a method for producing the same include copolymers described in U.S. Pat. No. 4035565 and International publication No. 2010/082633.

The aqueous dispersion of the fluorinated elastic copolymer may be obtained by dispersing the copolymer obtained by the production method described in the above-mentioned document in an aqueous medium, or may be obtained by directly or appropriately diluting the aqueous dispersion. Among them, the aqueous dispersion obtained is preferably used as it is or after being appropriately diluted.

Preferred examples of the copolymer include the following copolymers.

A copolymer comprising a TFE unit and a P unit, wherein the total amount of the TFE unit and the P unit is 65 to 100 mol% based on the total units (hereinafter referred to as a TFE-P copolymer). A copolymer comprising HFP units and VdF units, wherein the total of the HFP units and the VdF units is 50 to 100 mol% based on the total units (hereinafter referred to as HFP-VdF copolymer). A copolymer having a TFE unit and a PAVE unit, wherein the total of the TFE unit and the PAVE unit is 50 to 100 mol% based on the total units (hereinafter referred to as a TFE-PAVE copolymer). Among them, TFE-P copolymers are preferable.

The TFE-P copolymer is preferably a copolymer having a total of TFE units and P units of 65 to 100 mol% based on the total units of the copolymer and a molar ratio of TFE units/P units of 30/70 to 70/30. The molar ratio of TFE unit/P unit is preferably 45/55-65/35, more preferably 50/50-60/40. The TFE-P copolymer may contain 0.01 to 5.0 mass% of iodine atom.

As the unit other than the TFE unit and the P unit, a unit based on the monomer 1 represented by the following formula (1) (hereinafter referred to as unit 1.) is preferable.

CR¹R²＝CR³-R⁴-CR⁵＝CR⁶R⁷···(1)

(in the formula (1), R¹、R²、R³、R⁵、R⁶And R⁷Each independently is a hydrogen atom, a fluorine atom or a methyl group, R⁴The fluorine-containing compound is a perfluoroalkylene group having 1 to 10 carbon atoms or a group having an etheric oxygen atom at both ends, at one end or between carbon-carbon bonds of the perfluoroalkylene group. )

As monomer 1, CF can be exemplified₂＝CFO(CF₂)₃OCF＝CF₂、CF₂＝CFO(CF₂)₄OCF＝CF₂、CH₂＝CH(CF₂)₆CH＝CH₂。

The proportion of the unit 1 to the whole unit is preferably 0.05 to 1.5 mol%, more preferably 0.1 to 0.8 mol%, and still more preferably 0.15 to 0.6 mol%.

When the copolymer contains TFE units, P units, and units 1, the total of TFE units, P units, and units 1 is preferably 98 to 100 mol% based on the total units of the copolymer. The molar ratio of TFE unit/P unit is preferably 30/70 to 70/30, more preferably 45/55 to 65/35, and still more preferably 50/50 to 60/40.

As units other than the TFE unit, the P unit, and the unit 1, units based on the following monomers can be exemplified.

Fluoroolefin: monofluoroethylene, trifluoroethylene, trifluoropropene, pentafluoropropene, hexafluoropropene, hexafluoroisobutylene, dichlorodifluoroethylene, fluoroethylene, perfluorocyclobutene, pentafluorobutene, heptafluoropentene, nonafluorohexene, undecafluoroheptene

Hydrocarbon olefins: ethylene, 1-butene, isobutene, pentene

Alkyl vinyl ethers: methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, cyclohexyl vinyl ether

Vinyl ester: vinyl acetate, vinyl propionate, vinyl caproate, vinyl caprylate

Monomers other than the above: vinyl chloride, vinylidene chloride, trifluorostyrene

The other units are preferably 2.0 mol% or less, more preferably 1.0 mol% or less, and particularly preferably 0.5 mol% or less, based on the total units.

The TFE-P copolymer preferably contains an iodine atom. The iodine atom is preferably 0.01 to 5.0% by mass, more preferably 0.05 to 1.5% by mass, and still more preferably 0.1 to 1.0% by mass, based on the total mass of the copolymer. In the case where the amount is within this range, the rubber properties of the TFE-P copolymer are maintained and crosslinking becomes easy, so that the preferable range is obtained.

Examples of the method for introducing an iodine atom into the copolymer include: a method of using a monomer having an iodine atom as the other monomer, and a method of using a chain transfer agent having an iodine atom in polymerization. A chain transfer agent is preferably used because an iodine atom can be introduced into the end of the main chain of the copolymer and the crosslinking site can be easily controlled.

Examples of the chain transfer agent include 1, 4-diiodoperfluorobutane, 1, 2-diiodoperfluoroethane, 1, 3-diiodoperfluoropropane, 1, 5-diiodoperfluoropentane and 1, 6-diiodoperfluorohexane, and among them, 1, 4-diiodoperfluorobutane is preferable.

Examples of commercially available products of TFE-P copolymers include "AFLAS 100S", "AFLAS 100H", "AFLAS 150P", "AFLAS 150C", "AFLAS 150 CS", "AFLAS 300S", "AFLAS 400E" and "AFLAS 600S" (manufactured by AGC Co., Ltd.).

The HFP-VdF copolymer is preferably a copolymer in which the total of HFP units and VdF units is 50 to 100 mol% based on the total units of the copolymer and the molar ratio of VdF units/HFP units is 60/40 to 95/5. The molar ratio of the VdF unit to the HFP unit is preferably 70/30-90/10, and more preferably 75/25-85/15. The HFP-VdF copolymer may contain 0.01 to 5.0 mass% of iodine atoms.

As units other than the HFP unit and the VdF unit, a TFE unit is preferable. When the copolymer contains HFP units, VdF units, and TFE units, the total of HFP units, VdF units, and TFE units is preferably 98 to 100 mol% based on the total units of the copolymer. The molar ratio of VdF unit/TFE unit/HFP unit is preferably 50/5/45 to 65/30/5, more preferably 50/15/35 to 65/20/15.

As units other than the HFP unit, TFE unit, and VdF unit, units based on other monomers described below can be exemplified.

Other monomers: chlorotrifluoroethylene, trifluoroethylene, vinyl fluoride, ethylene, ethylidene norbornene, vinyl crotonate.

The other units are preferably 50 mol% or less, more preferably 30 mol% or less, and still more preferably 10 mol% or less, based on the total units.

Examples of commercially available HFP-VdF copolymers include: "DAI-EL G-801", "DAI-EL G-901", "DAI-EL G-902", "DAI-EL G-912", "DAI-EL G-952", "DAI-EL G-9074" and "DAI-EL G-9062" (manufactured by Dajin industries, Ltd.); "VITON GF-600S" (manufactured by Chemours); "TECNOFLON P959", "TECNOFLON P459", "TECNOFLON P757", "TECNOFLON P457" (manufactured by Solvay Specialty Polymers Japan Co., Ltd.), and the like.

The TFE-PAVE copolymer is preferably a copolymer having a total of 50 to 100 mol% of TFE units and PAVE units and a molar ratio of TFE units/PAVE units of 20/80 to 80/20. The molar ratio of TFE units/PAVE units is preferably 50/50-80/20, more preferably 60/40-75/25. The TFE-PAVE copolymer may contain 0.01 to 5.0 mass% of iodine atom.

Examples of PAVE include perfluoro (methyl vinyl ether), perfluoro (ethyl vinyl ether), perfluoro (propyl vinyl ether), perfluoro (methoxyethyl vinyl ether), perfluoro (propoxyethyl vinyl ether), and perfluoro (propoxypropyl vinyl ether).

Examples of the units other than the TFE unit and the PAVE unit include units based on other monomers exemplified in the above-mentioned TFE-P copolymer system and HFP-VdF copolymer system, and HFP and VdF.

The other units are preferably 50 mol% or less, more preferably 30 mol% or less, and still more preferably 10 mol% or less, based on the total units.

The TFE-PAVE copolymer preferably contains an iodine atom. The iodine atom is preferably 0.01 to 5.0% by mass, more preferably 0.05 to 1.5% by mass, and further preferably 0.1 to 0.5% by mass, based on the total mass of the copolymer. In the case where the amount is within this range, the rubber properties of the TFE-PAVE copolymer are maintained and crosslinking becomes easy, so that the amount is preferable.

The method of introducing an iodine atom into the copolymer and the preferable chain transfer agent are the same as those for the TFE-P type copolymer described above.

Examples of commercially available products of the TFE-PAVE copolymer described above include VITON GLT and VITON GFLT (manufactured by Chemours).

The fluorinated elastic copolymer is preferably contained in an amount of 10 to 40 parts by mass, more preferably 15 to 35 parts by mass, based on 100 parts by mass of the aqueous dispersion of the fluorinated elastic copolymer. Within this range, the elastic fluorocopolymer is easily dispersed uniformly in the aqueous dispersion, and also easily mixed with the aqueous dispersion of fluororesin, and is also easily aggregated.

D50 of the elastic fluorocopolymer contained in the aqueous elastic fluorocopolymer dispersion is preferably 30 to 200nm, more preferably 50 to 150 nm. Within this range, the elastic fluorocopolymer is less likely to precipitate, and is easily dispersed uniformly in the aqueous dispersion, and is also easily mixed with the aqueous dispersion of the fluororesin.

The aqueous dispersion of the fluorinated elastic copolymer preferably has a pH of 2.0 to 14.0, more preferably 7.0 to 14.0, still more preferably 9.0 to 14.0, and particularly preferably 11.0 to 13.0. When the aqueous dispersion of the elastic fluorocopolymer has a pH in this range, the absolute value of the difference between the pH and the pH of the aqueous dispersion of the fluororesin is easily 2.0 or less.

When the aqueous dispersion of the elastic fluorocopolymer has a pH in this range, the crosslinking properties of the fluororubber are easily improved. When the crosslinking property is improved, various physical properties of the fluororubber are improved, for example, tensile strength is improved and compression set is reduced. When the aqueous dispersion of the fluorinated elastic copolymer has a pH of 2.0 to 9.0, it is preferable to raise the pH to an appropriate range by using an aqueous solution of sodium hydroxide of 5% by mass or less. When the pH value is 13.0 to 14.0, an aqueous solution of sodium dihydrogen phosphate of 5 mass% or less can be used to lower the pH to an appropriate range.

In the method for producing the fluorinated elastic copolymer composition of the present invention, a tetrafluoroethylene polymer (hereinafter also referred to as "TFE polymer") is preferred as the fluororesin contained in the aqueous fluororesin dispersion.

The TFE-based polymer is preferably Polytetrafluoroethylene (PTFE), a copolymer of TFE and PAVE (PFA), a copolymer of TFE and HFP (FEP), a copolymer of TFE and ethylene (ETFE), or a copolymer of TFE and vinylidene fluoride, and PTFE is particularly preferable.

PTFE includes, in addition to a homopolymer of TFE, a copolymer of TFE and a very small amount (for example, 0.5 mol% or less based on the total units of the copolymer) of a comonomer (PAVE, HFP, FAE, or the like), that is, so-called modified PTFE. In addition, PFA may also comprise units based on monomers other than TFE and PAVE. The same applies to the other copolymers described above.

The TFE-based polymer is preferably a polymer obtained by emulsion polymerization of a fluoroolefin in water. As the aqueous dispersion of the fluororesin, an aqueous dispersion in which a polymer obtained by emulsion polymerization of a fluoroolefin in water is dispersed in water in the form of particles may be used as it is, or a powder may be recovered from water and dispersed in an aqueous medium.

The TFE-based polymer can be modified by surface treatment (radiation treatment, electron beam treatment, corona treatment, plasma treatment, and the like). Examples of the surface treatment method include methods described in international publication No. 2018/026012 and international publication No. 2018/026017.

The TFE-based polymer can be widely obtained as a commercially available product in the form of a dispersion liquid.

The melting point of the TFE polymer is preferably 280 ℃ or higher, more preferably 300 to 380 ℃, still more preferably 310 to 360 ℃, and particularly preferably 320 to 340 ℃.

The fluororesin aqueous dispersion preferably contains 1 to 70 parts by mass, more preferably 5 to 65 parts by mass of the fluororesin, per 100 parts by mass of the fluororesin aqueous dispersion. Within this range, the fluororesin is easily dispersed uniformly in the aqueous dispersion, and also easily mixed with the aqueous dispersion of the fluorinated elastic copolymer, and easily aggregated.

The fluororesin contained in the aqueous fluororesin dispersion preferably has a D50 of 200 to 400nm, more preferably 220 to 350 nm. Within this range, the fluororesin is less likely to precipitate, is easily dispersed uniformly in the aqueous dispersion, and is easily mixed with the aqueous dispersion of the fluorinated elastic copolymer.

The pH value of the fluororesin aqueous dispersion is preferably 7.0 to 14.0, more preferably 9.0 to 12.0. When the pH of the aqueous dispersion of a fluororesin is in this range, the absolute value of the difference between the pH of the aqueous dispersion of a fluororesin and the pH of the aqueous dispersion of a fluorinated elastic copolymer is easily 2.0 or less. Further, when the fluorine-containing elastic copolymer aqueous dispersion is mixed with the fluorine-containing elastic copolymer, the fluorine-containing resin is less likely to partially aggregate, and it is considered that the shrinkage deformation of the fluorine-containing rubber is prevented and the molding stability of the fluorine-containing rubber is improved.

When the aqueous dispersion of the fluororesin has a pH of 2.0 to 7.0, it is preferable to increase the pH to an appropriate range by using an aqueous ammonia solution of 30 mass% or less. When the pH value is 12.0 to 14.0, the pH can be reduced to an appropriate range by using a sodium dihydrogen phosphate aqueous solution of 5 mass% or less.

In the method for producing an elastic fluorocopolymer composition according to the present invention, the absolute value of the difference between the pH of the aqueous elastic fluorocopolymer dispersion and the pH of the aqueous fluororesin dispersion is 2.0 or less, more preferably 1.5 or less. When the absolute value is in this range, the elastic fluorocopolymer and the fluororesin are less likely to separate from each other and are easily dispersed and aggregated uniformly. In addition, when the fluororesin is polytetrafluoroethylene, the fluorinated elastic copolymer composition is likely to fibrillate, but fibrillation can be prevented by adjusting the pH. The pH can be adjusted by adding various pH adjusting agents. Further, the composition can be easily crosslinked by adjusting the pH without adding an acid absorbent to the composition.

When both the aqueous dispersion of the elastic fluorocopolymer and the aqueous dispersion of the fluororesin have a pH of 7.0 or more, the respective aqueous dispersions are stable, the fluororesin is less likely to be locally aggregated, and the elastic fluorocopolymer composition is easily crosslinked, so that a fluororubber having excellent crosslinking properties can be obtained.

The method for producing the fluorine-containing elastic copolymer composition of the present invention comprises: the aqueous dispersion of the elastic fluorocopolymer and the aqueous dispersion of the fluororesin are mixed to prepare an aqueous dispersion mixture containing the fluororesin in an amount of 0.5 to 20 parts by mass, preferably 1 to 10 parts by mass, based on 100 parts by mass of the elastic fluorocopolymer. When the content of the fluororesin is in this range, fibrillation or the like of the fluororesin is less likely to occur, and the hardness of the fluorine-containing elastic copolymer composition at the time of crosslinking is easily increased. In addition, mechanical strength and compression set were also excellent.

In the method for producing the elastic fluorocopolymer composition of the present invention, the method of aggregation may be a method of adding a coagulant to an aqueous dispersion mixture or a method of freezing the aqueous dispersion mixture.

As the aggregation method, in the case of adding a coagulant, a known coagulant may be used. As the known flocculant, aluminum salt, calcium salt or magnesium salt can be mentioned, specifically, aluminum sulfate and Al (SO) of the general formula M₄)₂·12H₂O [ wherein M' is a monovalent cation other than lithium. Alum, calcium nitrate, magnesium sulfate. Further, potassium chloride and sodium chloride as monovalent cations can also be used. In addition, ammonium acetate or ammonium carbonate may be used as the organic coagulant. In addition, nitric acid, which is an inorganic acid coagulant, may also be used.

In the case of freezing as the aggregation method, it is preferable to set the temperature to be 3 ℃ or more lower than the freezing point of the aqueous dispersion mixture. For example, it is preferably-8 ℃ or lower, more preferably-10 ℃ or lower. The aggregation time is preferably 0.5 hour or more, more preferably 1 hour or more. When the composition is cooled to a freezing point or lower and frozen, the composition can aggregate without using a coagulant, and therefore, the composition is suitable for use in applications where a metal content is to be reduced, such as semiconductor applications.

The elastic fluorocopolymer composition of the present invention preferably contains 0.5 to 20 parts by mass, more preferably 1 to 10 parts by mass of a fluororesin per 100 parts by mass of the elastic fluorocopolymer. When the content of the fluororesin is in this range, fibrillation or the like of the fluororesin is less likely to occur, and the hardness of the fluorine-containing elastic copolymer composition at the time of crosslinking is easily increased. In addition, mechanical properties and compression set were excellent.

In the fluorine-containing elastic copolymer composition of the present invention, a fluororesin is dispersed in the fluorine-containing elastic copolymer, and the average dispersed particle size of the fluororesin is 30 to 200 nm. The average dispersed particle diameter is preferably 50 to 150 nm. When the amount is within this range, the fluororesin is easily uniformly dispersed in the elastic fluorocopolymer. The average dispersed particle diameter of the fluororesin in the elastic fluorocopolymer composition was the same as the average dispersed particle diameter of the fluororesin in the crosslinked fluororubber.

The elastic fluorocopolymer and the fluororesin contained in the elastic fluorocopolymer composition of the present invention are exemplified by those described above in the method for producing the elastic fluorocopolymer composition of the present invention, and the preferred embodiments are the same.

Among these, the fluorinated elastic copolymer is preferably a TFE-P copolymer, and the fluororesin is preferably PTFE. By using these fluorinated elastic copolymer and fluororesin, the hardness can be improved without requiring an additive such as carbon black while maintaining the heat resistance, oil resistance, and the like of the fluororubber obtained by crosslinking the fluorinated elastic copolymer.

The cleaning solution of the fluorine-containing elastic copolymer composition of the present invention is preferably water or an aqueous alkaline solution. The pH value of the alkaline aqueous solution is preferably 10.0 to 14.0, and most preferably 12.0 to 14.0.

When the pH of the washing liquid is in this range, the tensile strength and hardness of the fluororubber described later are improved, and the compression set is improved, which is preferable.

The fluorine-containing elastic copolymer composition may be adjusted in hardness and compression set by adding additives such as carbon black, silica, and a resin filler having a D50 value of 1 μm or more. The amount of the fluorinated elastomer is preferably 1 to 30 parts by mass, more preferably 1 to 15 parts by mass, based on the fluorinated elastomer copolymer. The type of the resin filler is preferably PTFE, PFA, FEP, ETFE listed as TFE-based polymers, and PTFE, PFA, FEP are most preferable. D50 of the resin filler is preferably 1 to 50 μm, more preferably 1 to 20 μm. When D50 of the resin filler is in this range, the fluororesin derived from the aqueous dispersion of fluororesin and the resin derived from the resin filler are dispersed in a bimodal form, and it is considered that the crack resistance of the fluororubber described later can be improved.

Additives may be added to the elastic fluorocopolymer composition. The compression set can be improved by adding an acid absorbent such as sodium stearate, calcium stearate, benzyltriphenylphosphonium chloride (BTPPC), 2-ethyl-4-methylimidazole (2E4MZ), etc. Among them, BTPPC is most preferable.

The fluororubber is obtained by crosslinking the above-mentioned fluorine-containing elastic copolymer composition.

As a method for crosslinking the elastic fluorocopolymer composition (i.e., the elastic fluorocopolymer in the elastic fluorocopolymer composition), a method of crosslinking the elastic fluorocopolymer composition by heating is preferred.

Specific examples of the crosslinking method by heating include hot-press crosslinking, steam crosslinking, and hot-air crosslinking. The shape and use of the elastic fluorocopolymer composition may be appropriately selected from these methods.

The heating condition is preferably 100 to 400 ℃ for 1 second to 24 hours.

The fluororubber obtained by crosslinking the heated elastic fluorocopolymer composition 1 time may be further crosslinked 2 times by heating. By performing the 2-time crosslinking, the mechanical properties, compression set, and other properties of the fluororubber can be stabilized or improved.

The heating condition for 2 times of crosslinking is preferably 100 to 300 ℃ for 30 minutes to 48 hours.

As a crosslinking method other than crosslinking the elastic fluorocopolymer composition by heating, there can be mentioned a method of crosslinking the elastic fluorocopolymer composition by irradiation with radiation. Specific examples of the radiation to be irradiated include electron beams and ultraviolet rays.

The proportion of the fluororesin contained in the fluororubber is preferably 0.5 to 20 parts by mass, and more preferably 1 to 10 parts by mass, based on 100 parts by mass of the fluororubber-derived elastic copolymer component. When the amount is within this range, the fluororubber has high hardness and excellent mechanical properties and compression set.

The fluororesin contained in the fluororubber is dispersed in the fluororubber, and the average dispersed particle size of the fluororesin is preferably 30 to 200nm, more preferably 50 to 150 nm. When the amount is within this range, the fluororesin is easily uniformly dispersed in the fluororubber.

The molded article of the present invention is excellent in heat resistance, mechanical strength, post-processability, plasma resistance and gas barrier property. Further, since the finely dispersed fine particles of the fluororesin are less likely to fall off from the elastomer of the matrix, there is no fear of generation of particles even when used as a sealing member for a semiconductor manufacturing apparatus, for example. Specific applications of the fluororubber molded product of the invention include gaskets and sealing materials in semiconductor manufacturing apparatuses and various factories such as petrochemical plants.

Examples

The following examples illustrate the invention in detail. Examples 1 to 4 are examples, and examples 5 to 8 are comparative examples.

[ D50 of fluororesin contained in fluororesin aqueous dispersion ]

D50 was measured by using a laser light scattering particle size distribution analyzer (LA-920 (product name) manufactured by horiba, Ltd.).

[ D50 of fluorinated elastic copolymer contained in aqueous dispersion of fluorinated elastic copolymer ]

D50 was measured by a dynamic light scattering method using a laser zeta potentiometer (FPAR-1000 available from Otsuka electronics Co., Ltd. (trade name)).

[ average dispersed particle diameter of fluororesin contained in fluororubber ]

The fluororubber was sliced with a cryomicrotome, and the obtained sample was placed on a wafer, coated, and observed by SEM using SU8230 manufactured by hitachi high and new technologies, to measure the average dispersed particle diameter. In table 2, the case where molding was difficult and SEM observation was not possible is indicated as x.

[ measurement of storage modulus G' ]

The storage modulus was measured at 100 ℃ under an amplitude of 0.5 degrees and a frequency of 50 times/min according to ASTM D5289 and D6204 using RPA2000 (produced by Alpha Technologies, Inc.).

[ confirmation of fibrillation ]

The resulting composition (hereinafter, also referred to as "crosslinkable elastic fluorocopolymer composition") was visually checked to find that it was O when it was transparent and that it was X when it was partially white and streaks were visible.

[ measurement of tensile Property ]

The crosslinkable elastic fluorocopolymer composition was hot-pressed at 160 ℃ for 20 minutes (1-time crosslinking), and then subjected to 2-time crosslinking at 200 ℃ for 4 hours in an oven to obtain a crosslinked rubber sheet having a thickness of 1 mm. The crosslinked rubber sheet thus obtained was cut with a No. 4 dumbbell to prepare a measurement sample, and tensile properties (tensile strength, elongation) were measured at 25 ℃ in accordance with JIS K6251.

[ measurement of hardness ]

Shore A hardness was measured in accordance with JIS K6253.

[ measurement of compression permanent Strain ]

The crosslinkable fluorinated elastic copolymer composition was hot-pressed at 160 ℃ for 20 minutes (1-time crosslinking), and then subjected to 2-time crosslinking in an oven at 200 ℃ for 4 hours to obtain a P-26O-ring. The molded article was used as a measurement sample, and a compression set test was carried out at 200 ℃ for 70 hours in accordance with JIS K6262 to measure the compression set.

[ deformation Strain ]

A sheet 1mm thick for measuring physical properties was produced, and the sheet after secondary vulcanization was evaluated as good when the flatness was maintained in a plate-like state, and as good when the sheet after secondary vulcanization was uneven and not flat.

(production example 1: preparation of an aqueous PTFE Dispersion ]

To be provided withA100L stainless autoclave equipped with a baffle plate and a stirrer was charged with F (CF)₂)₂OCF₂CF₂OCF₂COONH₄(hereinafter also referred to as EEA)36g, paraffin wax (melting point: 55 ℃ C.) 555g, and deionized water 61.3 liters. After the inside of the autoclave was replaced with nitrogen, TFE was introduced under reduced pressure, and the temperature was raised to 62 ℃ with stirring. TFE was further introduced thereinto to make the internal pressure 1.765MPa [ gauge pressure ]]26.3g of disuccinic acid peroxide (concentration 80% by mass, remainder moisture) was dissolved in 1 liter of warm water of about 70 ℃ and injected.

After about 3 minutes, the internal pressure of the autoclave was reduced to 1.716MPa [ gauge ], so that polymerization was carried out by feeding TFE into the autoclave while maintaining the internal pressure at 1.765MPa [ gauge ]. During the polymerization, 53g of EEA was dissolved in warm water and co-injected in 2 portions. The autoclave temperature was gradually raised to 72 ℃ and the reaction was terminated when the amount of TFE introduced reached 22kg, and TFE in the autoclave was released into the atmosphere. The polymerization time was 105 minutes. After cooling, the paraffin wax solidified on the upper portion was removed to obtain an aqueous PTFE emulsion. The PTFE concentration in the PTFE aqueous emulsion was about 25.0 mass%, and the EEA concentration was 0.40 mass% with respect to the mass of PTFE. The PTFE particles in the aqueous emulsion had a D50 of 0.26. mu.m. The average molecular weight of PTFE was 76 ten thousand, and the standard specific gravity of PTFE was 2.21.

10kg of the obtained aqueous PTFE emulsion was used to dissolve a nonionic surfactant (Newcol (registered trademark) 1308FA) having a PTFE concentration of 24.2 mass% and ion-exchanged water in an amount of 2.7 mass% based on the mass of PTFE, thereby obtaining a PTFE low-concentration aqueous dispersion having a PTFE concentration of 24.2 mass%.

Subsequently, 5kg of the obtained low concentration aqueous emulsion of PTFE and 200g of a strongly basic anion exchange resin (PUROLITE (registered trademark) A300, manufactured by PUROLITE CORPORATION) were added to a 5L beaker, and stirred at room temperature for 12 hours. Further, this aqueous dispersion was filtered through a nylon mesh having a mesh size of 100, and then concentrated by electrophoresis, and the supernatant was removed to obtain a concentrated solution (PTFE aqueous dispersion) containing 65 mass% of PTFE particles and 2.0 mass parts of a nonionic surfactant per 100 mass parts of PTFE particles.

Using the obtained concentrated solution, a nonionic surfactant (Newcol (registered trademark) 1308FA) and ion-exchanged water were dissolved so that the content of the nonionic surfactant was 2.8 mass% with respect to the mass of PTFE. Ion-exchanged water was added so that the concentration of PTFE became 60.5% by mass, to obtain an aqueous PTFE dispersion.

The pH of the obtained PTFE aqueous dispersion was confirmed with pH test paper to be 10.0.

(production example 2: preparation of an aqueous dispersion of a fluorine-containing elastic copolymer

A pressure-resistant reactor made of stainless steel and having an internal volume of 3200mL and equipped with anchor blades for stirring was degassed, and then 1600g of ion-exchanged water, 13g of disodium hydrogenphosphate dodecahydrate, 1g of sodium hydroxide, 9g of sodium lauryl sulfate, 96g of t-butanol, 7g of perfluoro-3, 7-dioxa-nonadiene-1, 89 g of 1, 4-diiodoperfluorobutane and 6g of ammonium persulfate were charged into the reactor. Further, 0.4g of ethylenediaminetetraacetic acid disodium salt dihydrate (hereinafter referred to as EDTA) and 0.3g of ferrous sulfate heptahydrate were dissolved in 100g of ion-exchanged water, and the resulting aqueous solution was charged into a reactor. At this time, the pH of the aqueous medium in the reactor was 8.6.

Next, a monomer mixed gas of TFE/P (molar ratio) 88/12 was introduced at 25 ℃ so that the internal pressure of the reactor became 2.47MPa [ gauge pressure ]. The anchor blade was rotated at 300rpm, a 2.3 mass% aqueous solution of rongalite adjusted to a pH of 13.0 with sodium hydroxide (hereinafter referred to as a 2.3 mass% aqueous solution of rongalite) was added to the reactor, and polymerization was started. Thereafter, a 2.3 mass% aqueous solution of rongalite was continuously fed into the reactor by a high-pressure pump.

Since the pressure in the reactor decreases as the polymerization proceeds, when the internal pressure of the reactor decreases to 2.46MPa [ gauge ], a monomer mixed gas having a TFE/P ratio of 56/44 (molar ratio) is introduced by its own pressure, and the internal pressure of the reactor is increased to 2.48MPa [ gauge ]. The polymerization reaction is continued by repeating this operation while maintaining the internal pressure of the reactor at 2.46 to 2.48MPa [ gauge pressure ]. When the total amount of the TFE/P monomer mixed gas introduced reached 800g, the addition of the 2.3 mass% aqueous solution of rongalite was stopped, and when the total amount of the TFE/P monomer mixed gas introduced reached 900g, the internal temperature of the reactor was cooled to 10 ℃ and the polymerization reaction was stopped by returning to normal pressure, thereby obtaining an aqueous dispersion of the fluorinated elastic copolymer. The amount of rongalite 2.3 mass% aqueous solution added was 61 g. The polymerization time was 7 hours. The solid content in the latex was 33% by mass, and the D50 value of the fluorine-containing elastic copolymer particles was 0.06. mu.m. The fluorinated elastic copolymer had a copolymerization composition of 56/44 (molar ratio) of TFE units/P units and a glass transition temperature of-3 ℃. The pH of the latex was confirmed with pH test paper and found to be 6.0.

[ example 1]

To the aqueous dispersion of the fluorinated elastic copolymer obtained in production example 2, a2 mass% aqueous solution of sodium hydroxide was added dropwise to adjust the pH to 9.0. To this prepared solution, the aqueous dispersion of PTFE obtained in production example 1 was mixed so that the ratio of the fluorinated elastic copolymer/PTFE was 100/2.5 (mass ratio of solid content), thereby obtaining an aqueous dispersion mixture. The aqueous dispersion mixture was allowed to stand in a refrigerator at-22 ℃ for 15 hours to freeze-aggregate, washed with water, and dried to obtain a fluorinated elastic copolymer composition in which fine particles of a fluororesin were dispersed in a fluorinated elastic copolymer. The fluoroelastomer copolymer composition had a storage modulus G' of 348 kPa.

To 102.5 parts by mass of the obtained fluorinated elastic copolymer composition, 1 part by mass of bis (2-t-butylperoxyisopropyl) benzene (P-14 in table 2) as a crosslinking agent and 3 parts by mass of triallyl isocyanurate (TAIC in table 2) as a crosslinking accelerator were mixed and kneaded by an open roll mill to obtain a crosslinkable fluorinated elastic copolymer composition. The composition was visually checked and judged to have not fibrillated. The crosslinkable fluorinated elastic copolymer composition was subjected to pressure crosslinking at 160 ℃ for 20 minutes and then to oven crosslinking at 200 ℃ for 4 hours to obtain a crosslinked fluororubber. The fluororubber was confirmed to be in a flat state without deformation strain, and the normal physical properties were measured. Further, an O-ring (P-26) was produced under the same crosslinking conditions, and the compression set was measured.

[ example 2]

A fluorinated elastic copolymer composition was obtained in the same manner as in example 1, except that the fluorinated elastic copolymer/PTFE was changed to the values shown in table 1. Further, a crosslinkable fluorinated elastic copolymer composition and a fluororubber were obtained in the same manner as in example 1, except that the values shown in Table 2 were changed.

[ example 3]

A fluorinated elastic copolymer composition was obtained in the same manner as in example 1, except that the fluorinated elastic copolymer composition was obtained by chemical aggregation. Further, a crosslinkable fluorinated elastic copolymer composition and a fluororubber were obtained in the same manner as in example 1, except that the values shown in Table 2 were changed. Chemical polymerization was carried out by preparing a 25% aqueous solution (coagulant) of KCl in an amount equivalent to the mass of the aqueous dispersion mixture, adding the aqueous dispersion mixture dropwise to the 25% aqueous solution of KCl to cause aggregation, washing with water, and drying to obtain a fluorinated elastic copolymer composition in which fluorine resin fine particles were finely dispersed in a fluorinated elastic copolymer.

[ example 4]

A fluorinated elastic copolymer composition was obtained in the same manner as in example 1 except that a2 mass% aqueous solution of sodium hydroxide was added dropwise to the aqueous dispersion of the fluorinated elastic copolymer obtained in production example 2 to adjust the pH to 11.0. Further, a crosslinkable fluorinated elastic copolymer composition and a fluororubber were obtained in the same manner as in example 1, except that the values shown in Table 2 were changed.

[ example 5]

A fluorinated elastic copolymer composition was obtained in the same manner as in example 1, except that the fluorinated elastic copolymer/PTFE was changed to the values shown in table 1. It is to be noted that a crosslinkable fluorinated elastic copolymer composition was obtained in the same manner as in example 1 except that the values shown in Table 2 were changed, but the composition was strongly fibrillated and hardly molded during kneading with an open mill, and thus, no normal physical properties could be obtained.

[ example 6]

PTFE was not added to the fluorine-containing elastic copolymer, and CaCl was used₂Except that the aqueous solution (coagulant) of 2% was used as the chemical coagulation, the fluorinated elastic copolymer was chemically coagulated in the same manner as in example 3. A crosslinkable fluorinated elastic copolymer composition and a fluororubber were obtained in the same manner as in example 1, except that the values shown in Table 2 were changed.

[ example 7]

To the fluorinated elastic copolymer obtained in example 6, PTFE (Fluon PTFE L169J, manufactured by AGC Co.) was added during kneading with an open mill to obtain a crosslinkable fluorinated elastic copolymer composition and a fluororubber. The amount of PTFE is reported in table 1.

[ example 8]

A fluorinated elastic copolymer composition was obtained in the same manner as in example 1 except that the pH of the aqueous dispersion of a fluorinated elastic copolymer obtained in production example 2 was not adjusted. It is to be noted that a crosslinkable fluorinated elastic copolymer composition was obtained in the same manner as in example 1 except that the values shown in Table 2 were changed, but the composition was strongly fibrillated and hardly molded during kneading with an open mill, and thus, no normal physical properties could be obtained.

[ Table 1]

[ Table 2]

[ example 9]

In the step after freeze aggregation to obtain a fluorinated elastic copolymer composition of example 1, washing was performed using a 1 mass% NaOH aqueous solution (pH 14.0) as an alkaline aqueous solution instead of water washing, and then water washing was performed until the water of the washing liquid reached pH10.0, to obtain a fluorinated elastic copolymer composition. Fluororubber was obtained in the same manner as in example 1, except that the cleaning solution was changed.

[ example 10]

A fluororubber was obtained in the same manner as in example 9 except that the aqueous alkaline solution of example 9 was changed to a 1% by mass KOH aqueous solution (pH 14.0).

[ example 11]

A fluororubber was obtained in the same manner as in example 9 except that, when a crosslinkable fluorinated elastic copolymer composition was obtained using the fluorinated elastic copolymer composition obtained in example 9, 0.2 parts by mass of BTPPC was added as an additive.

[ example 12]

A fluororubber was obtained in the same manner as in example 11, except that the amount of BTPPC added was changed to 0.7 parts by mass.

[ example 13]

A fluororubber was obtained in the same manner as in example 11, except that the type of the additive was changed to 2E4 MZ.

[ example 14 ]

A fluororubber was obtained in the same manner as in example 12 except that, when a crosslinkable fluorinated elastic copolymer composition was obtained using the fluorinated elastic copolymer composition obtained in example 12, 3 parts by mass of a resin filler (PTFE) was further added.

The fluororubber thus obtained was observed in a test piece after the compression set test, and as a result, no crack was observed in the test piece.

[ example 15 ]

A fluororubber was obtained in the same manner as in example 14, except that the resin filler (PTFE) was changed to a resin filler (PFA).

The fluororubber thus obtained was observed in a test piece after the compression set test, and as a result, no crack was observed in the test piece.

The reagents and resin fillers used in examples 11 to 15 are as follows.

[BTPPC]

Fuji film and benzyltriphenylphosphonium chloride manufactured by Wako pure chemical industries, Ltd

[2E4MZ]

2-Ethyl-4-methylimidazole manufactured by Siguo Kagaku K.K

[ resin Filler (PTFE) ]

Fluon PTFE L173J manufactured by AGC corporation (D50: 7.0 μm)

[ resin Filler (PFA) ]

Consisting of TFE units/5-norbornene-2, 3-dicarboxylic anhydride units/CF₃CF₂CF₂OCF＝CF₂Powder of PFA polymer (melting temperature: 300 ℃) having a unit of 98.0/0.1/1.9 (mol%) (D50: 1.8 μm, D90: 5.2 μm)

The results of examples 9 to 15 are shown in Table 3. In example 1, a part of example 1 described in table 2 is described again. In addition, the average dispersed particle diameter of the fluororesins of examples 14 and 15 is not the value of PTFE derived from the resin filler but from the PTFE aqueous dispersion of production example 1.

[ Table 3]

The entire contents of the specification, claims, drawings and abstract of japanese patent application No. 2019-071313 filed on 4/3 in 2019 are incorporated herein as the disclosure of the specification of the present invention.