JP5061510B2 - Fluorine-containing elastic copolymer composition and crosslinked rubber - Google Patents

Description

  The present invention relates to a fluorinated elastic copolymer composition excellent in fluidity during molding and a crosslinked rubber excellent in cross-linked physical properties.

Known fluorine-containing elastic copolymers include vinylidene fluoride / hexafluoropropylene copolymer, tetrafluoroethylene / propylene copolymer, tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymer, and the like. .
Since these fluorinated elastic copolymers are excellent in heat resistance and chemical resistance, they are applied to harsh environments where ordinary materials cannot withstand.
However, depending on the shape of the mold at the time of molding and the composition of the composition of the fluorinated elastic copolymer blended with a crosslinking agent, etc., the fluidity may not be sufficient, improving the fluidity at the time of molding. There is a need for a way to do this.

In addition, these fluorine-containing elastic copolymers are poor in reactivity, so that crosslinking reactivity and adhesion to other materials are not sufficient, and a method for improving reactivity by introducing reactive functional groups has been proposed. Has been.
Generally, a rubber material needs to express appropriate physical properties by a crosslinking reaction, except for some thermoplastic elastomers. For this reason, a crosslinkable functional group is introduced into the molecule of fluororubber. For vinylidene fluoride / hexafluoropropylene copolymers, iodine atoms and unsaturated bonds have been proposed as reactive functional groups.

For tetrafluoroethylene / propylene copolymers, which have better chemical resistance than vinylidene fluoride / hexafluoropropylene copolymers, especially amine resistance and high temperature steam resistance, crosslinkable functional groups such as vinyl ester monomers A fluorinated elastic copolymer obtained by copolymerizing a monomer containing a group has been proposed (see, for example, Patent Document 1).
In order to crosslink this tetrafluoroethylene / vinyl ester monomer / propylene copolymer, an unsaturated polyfunctional compound such as triallyl isocyanurate and a crosslinking agent such as an organic peroxide are mixed to further improve the crosslinkability. In order to achieve this, it has been proposed to mix divalent metal oxides, and the composition obtained by mixing these components can be molded, has excellent crosslinkability, and has excellent crosslinkable rubber properties. Has been found.

However, this composition has a problem that the Mooney viscosity is high and the fluidity in a cavity having a complicated shape in a mold is not sufficient at the time of molding.
Therefore, development of a composition containing a tetrafluoroethylene / vinyl ester monomer / propylene copolymer and having excellent fluidity and crosslinkability has been demanded.

On the other hand, it is known that a processing aid such as a fatty acid monoamide is added to a vinylidene fluoride / hexafluoropropylene copolymer to improve releasability (see, for example, Patent Document 2). However, it is not known that processing aids such as fatty acid monoamides improve the crosslinkability of the fluoropolymer composition, and processing aids such as fatty acid monoamides do not flow in the fluoropolymer composition. No effect on sex was known.

JP 2006-70245 A Japanese Patent Laid-Open No. 7-196879

An object of the present invention is to provide a fluorine-containing elastic copolymer obtained by copolymerizing a specific fluorine-containing monomer such as tetrafluoroethylene , a specific vinyl ester monomer, and, if necessary, an unsaturated hydrocarbon monomer such as ethylene. It is a composition containing a polymer, and provides a fluorinated elastic copolymer composition having excellent fluidity at the time of molding processing. Further, it is excellent in fluidity at the time of molding processing and has a crosslinking reactivity. The present invention also provides an excellent fluorinated elastic copolymer composition. The present invention also provides a crosslinked rubber having excellent properties of a crosslinked rubber obtained by crosslinking it.

The present inventors have prepared a fluorine-containing elastic copolymer obtained by copolymerizing a specific fluorine-containing monomer such as tetrafluoroethylene , a specific vinyl ester monomer, and, if necessary, an unsaturated hydrocarbon monomer such as ethylene. By blending the polymer with at least one selected from the group consisting of unsaturated polyfunctional compounds and aliphatic amines and monovalent metal salts of aliphatic carboxylic acids, it has excellent crosslinking reactivity and flow during molding. A fluorinated elastic copolymer composition having excellent properties was obtained, and the cross-linked rubber obtained by cross-linking it was found to be excellent in cross-linked rubber properties, thereby completing the present invention.

That is, the present invention relates to (A) tetrafluoroethylene, hexafluoropropylene, vinylidene fluoride, CF ₂ ═CF—O—R ^f (wherein R ^f is a saturated perfluoroalkyl group having 1 to 8 carbon atoms or perfluoro (alkoxyalkyl) group. repeating units based on one or more fluorine-containing monomer selected from the group consisting of perfluoro vinyl ether represented by) (l), and the general formula CR 1 ^R 2 ⁼ CR ³ COOCH═CH ₂ (wherein R ¹ and R ² are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkoxyalkyl group having 1 to 10 carbon atoms including an etheric oxygen atom) , R ³ is a hydrogen atom, a fluorine atom or a methyl group.) Fluorinated elastic copolymer containing, by containing at least one selected from the group consisting of monovalent metal salt of (B) an unsaturated multifunctional compound and (C) an aliphatic amine and aliphatic carboxylic acids Provided is a fluorinated elastic copolymer composition.
In the fluorinated elastic copolymer composition according to the present invention, (A) may further include ethylene, propylene, a general formula CH ₂ ═CH—O—R ⁴ (wherein R ⁴ represents the number of carbon atoms). A fluorinated elastic copolymer containing a repeating unit (n) based on one or more hydrocarbon monomers selected from the group consisting of vinyl ethers represented by 1 to 8 saturated alkyl groups or alkoxyalkyl groups. A fluorinated elastic copolymer composition is provided.

In the fluorinated elastic copolymer composition, the content ratio of the repeating unit in (A) is (m) / ((l) + (n)) = 0.0001 to 0.1. A fluorine-containing elastic copolymer composition having a (molar ratio) is provided.
Further, the present invention provides the above fluorinated elastic copolymer composition, wherein (C) is a fluorinated elastic copolymer composition in which a monovalent metal salt of an aliphatic amine and an aliphatic carboxylic acid is used in combination. provide.
The present invention further provides (D) a fluorine-containing elastic copolymer composition further containing (D) an organic peroxide in the fluorine-containing elastic copolymer composition.
In the fluorinated elastic copolymer composition, the content ratio of the repeating unit (n) in the above (A) is (n) / (l) = 1/99 to 70/30 (mol). Ratio) of the fluorinated elastic copolymer composition.
The present invention also provides the fluorinated elastic copolymer composition, wherein R ² and R ³ in the vinyl ester monomer are hydrogen atoms.

The present invention also provides the fluorinated elastic copolymer composition, wherein the vinyl ester monomer is vinyl crotonate.
In the fluorinated elastic copolymer composition according to the present invention, the fluorinated monomer is tetrafluoroethylene, the hydrocarbon monomer is propylene, and (n) / (l) = 40/60 to 60 The fluorinated elastic copolymer composition is / 40 (molar ratio) and (m) / ((l) + (n)) = 0.0001 to 0.05 (molar ratio) .
Furthermore, the present invention provides a crosslinked rubber obtained by crosslinking the fluorinated elastic copolymer composition.

  The fluorinated elastic copolymer composition of the present invention has rubber elasticity and excellent fluidity during molding. Moreover, a specific thing can exhibit the especially outstanding crosslinking reactivity and fast crosslinking speed. The crosslinked rubber obtained by crosslinking the fluorinated elastic copolymer composition of the present invention is excellent in physical properties of the crosslinked rubber, particularly excellent in chemical resistance, heat resistance, weather resistance and the like.

The fluorinated elastic copolymer of component (A) used in the present invention is tetrafluoroethylene, hexafluoropropylene, vinylidene fluoride, general formula CF ₂ ═CF—O—R ^f (wherein R ^f is carbon A saturated perfluoroalkyl group or a perfluoro (alkoxyalkyl) group having 1 to 8 atoms.) Repeating unit (l) based on one or more fluorine-containing monomers selected from the group consisting of perfluorovinyl ethers Containing.

Hereinafter, tetrafluoroethylene is TFE, hexafluoropropylene is HFP, vinylidene fluoride is VdF, perfluorovinyl ether represented by the general formula CF ₂ ═CF—O—R ^f is PAVE, and perfluoro (methyl vinyl ether) is PMVE, Perfluoro (propyl vinyl ether) is called PPVE. Ethylene is referred to as E and propylene is referred to as P.

The fluorinated elastic copolymer may be a copolymer using only one type of fluorinated monomer, or may be a copolymer using a combination of two or more types of fluorinated monomers. A fluorine-containing elastic copolymer using only one kind of fluorine monomer is preferred. As the fluorine-containing elastic copolymer using only one kind of fluorine-containing monomer, a TFE copolymer is preferable.
Examples of the fluorinated elastic copolymer using one type of fluorinated monomer include TFE / P copolymers, E / PAVE copolymers, E / HFP copolymers, and the like. A TFE / P copolymer is preferred.

Fluorine-containing elastic copolymers using two or more types of fluorine-containing monomers include VdF / HFP copolymers, TFE / VdF / HFP copolymers, TFE / PAVE copolymers, and TFE / PMVE copolymers. Examples thereof include a copolymer, a TFE / PPVE copolymer, a TFE / P / VdF copolymer, a TFE / PMVE / PPVE copolymer, and a VdF / PAVE copolymer.
Fluorine-containing elastic copolymers include TFE / P copolymers, TFE / P / VdF copolymers, VdF / HFP copolymers, TFE / VdF / HFP copolymers, TFE / PPVE copolymers. A polymer and a TFE / PMVE / PPVE copolymer are preferable.

The fluorinated elastic copolymer of the present invention more preferably has the following copolymer composition. When the copolymer composition is in the following range, the crosslinked rubber is excellent in the properties of the crosslinked rubber and has good heat resistance, chemical resistance, and low temperature characteristics.
In TFE / P copolymer, repeating unit based on TFE / repeating unit based on P = 40/60 to 60/40 (molar ratio),
TFE / P / VdF copolymer: TFE-based repeating unit / P-based repeating unit / VdF-based repeating unit = 40-60 / 60-40 / 1-10 (molar ratio), VdF / HFP-based copolymer In the coalescence, repeating unit based on VdF / repeating unit based on HFP = 20/80 to 95/5 (molar ratio),

In TFE / VdF / HFP copolymer, repeating unit based on TFE / repeating unit based on VdF / repeating unit based on HFP = 20-40 / 20-40 / 20-40 (molar ratio),
In TFE / PAVE copolymer, repeating unit based on TFE / repeating unit based on PAVE = 40/60 to 70/30 (molar ratio),
In TFE / PMVE copolymer, repeating unit based on TFE / repeating unit based on PMVE = 40/60 to 70/30 (molar ratio),

In TFE / PPVE copolymer, repeating unit based on TFE / repeating unit based on PPVE = 40/60 to 70/30 (molar ratio),
In TFE / PMVE / PPVE copolymer, repeating unit based on TFE / repeating unit based on PMVE / repeating unit based on PPVE = 40 to 70/3 to 57/3 to 57 (molar ratio),
In the VdF / PAVE copolymer, the repeating unit based on VdF / the repeating unit based on PAVE = 60/40 to 95/5 (molar ratio),
In the E / PAVE copolymer, the repeating unit based on E / the repeating unit based on PAVE = 40/60 to 60/40 (molar ratio),
In the E / HFP copolymer, the repeating unit based on E / the repeating unit based on HFP = 40/60 to 60/40 (molar ratio).

The fluorinated elastic copolymer used in the present invention has a general formula CR ¹ R ² ═CR ³ COOCH═CH ₂ (wherein R ¹ and R ² are each represented by the formula (1) based on the fluorinated monomer). Independently, it is a hydrogen atom, an alkyl group having 1 to 10 carbon atoms or an alkoxyalkyl group having 1 to 10 carbon atoms including an etheric oxygen atom, and R ³ is a hydrogen atom, a fluorine atom or a methyl group.) The repeating unit (m) based on the vinyl ester monomer represented by these is contained .

As the vinyl ester monomer, R ² and R ³ are preferably hydrogen atoms. As specific examples, vinyl crotonate in which R ¹ is a methyl group and R ² and R ³ are hydrogen atoms and vinyl methacrylate in which R ¹ , R ² and R ³ are hydrogen atoms are preferable, and vinyl crotonate is more preferable. preferable.
The vinyl ester monomer may be used alone or in combination of two or more.
Since the vinyl ester monomer has two carbon-carbon unsaturated double bonds, one carbon-carbon unsaturated double bond is used for copolymerization with a fluorine-containing monomer, and the other carbon-carbon unsaturated double bond is used. The saturated double bond remains in the fluorinated elastic copolymer for use in the crosslinking reaction.

In addition to the repeating units (l) and (m), the fluorinated elastic copolymer used in the present invention includes E, P, a general formula CH ₂ ═CH—O—R ⁴ (wherein R ⁴ is carbon It is preferably a repeating unit (n) based on one or more hydrocarbon monomers selected from the group consisting of vinyl ethers represented by the following formula: a saturated alkyl group having 1 to 8 atoms or an alkoxyalkyl group. As the hydrocarbon monomer, E and P are preferable, and P is more preferable. Only one type of hydrocarbon monomer may be used, or two or more types may be used in combination.

In the fluorinated elastic copolymer, the repeating unit ratio (n) / (l) is preferably 1/99 to 70/30 (molar ratio), more preferably 20/80 to 65/35 (molar ratio). 60/40 to 40/60 (molar ratio) is more preferable. Within this range, the fluorinated elastic copolymer has excellent cross-linked rubber properties and good heat resistance, chemical resistance, and low temperature characteristics.
The content of the repeating unit (m) based on the vinyl ester monomer is a ratio of (m) / ((l) + (n)) = 0.0001 to 0.1 (molar ratio), and (m) / A ratio of ((l) + (n)) = 0.0001 to 0.05 (molar ratio) is preferable, (m) / ((l) + (n)) = 0.005 to 0.01 (molar ratio) ) Is more preferable, and a ratio of (m) / ((l) + (n)) = 0.001 to 0.008 (molar ratio) is particularly preferable. Within this range, the fluorinated elastic copolymer is excellent in cross-linking reactivity, and the resulting cross-linked rubber is excellent in cross-linked rubber properties such as tensile strength, chemical resistance, heat resistance and compression set.

  The Mooney viscosity (MS1 + 4 (100 ° C.)) of the fluorinated elastic copolymer is preferably 20 to 150, more preferably 30 to 150. Mooney viscosity is a measure of molecular weight. A large molecular weight indicates a high molecular weight, and a small molecular weight indicates a low molecular weight. Within this range, the processability and cross-linked rubber properties of the fluorinated elastic copolymer are good. The Mooney viscosity is measured in accordance with JIS K6300 using an S-shaped rotor with a diameter of 30.48 mm and a thickness of 5.54 mm, setting a preheating time of 1 minute and a rotor rotation time of 4 minutes at 100 ° C. Value.

Examples of the method for producing the fluorinated elastic copolymer used in the present invention include emulsion polymerization, solution polymerization, suspension polymerization, bulk polymerization and the like. Moreover, a radical polymerization initiator, a redox polymerization initiator, heat, radiation, etc. can be used for the initiation reaction. Emulsion polymerization is preferred because of excellent adjustment of molecular weight and copolymer composition and productivity.
As a specific method for producing the fluorinated elastic copolymer, and optionally, the fluorinated monomer, the vinyl ester monomer, and, if necessary, the hydrocarbon monomer are radicalized in the presence of a radical polymerization initiator. The method of implementing copolymerization is mentioned. The radical copolymerization is preferably carried out in the presence of a chain transfer agent. Furthermore, the radical polymerization is more preferably emulsion polymerization in the presence of an emulsifier in an aqueous medium.

  As the aqueous medium, water or water containing a water-soluble organic solvent is preferable. Examples of the water-soluble organic solvent include tert-butanol, propylene glycol, dipropylene glycol, dipropylene glycol monomethyl ether, and tripropylene glycol. Tert-butanol, propylene glycol, and dipropylene glycol monomethyl ether are preferred. When the aqueous medium contains a water-soluble organic solvent, the content of the water-soluble organic solvent is preferably 1 to 50 parts by mass, more preferably 3 to 20 parts by mass with respect to 100 parts by mass of water.

As the emulsifier, an ionic emulsifier excellent in mechanical and chemical stability of the latex is preferable, and an anionic emulsifier is more preferable. Examples of the anionic emulsifier include hydrocarbon emulsifiers such as sodium lauryl sulfate and sodium dodecylbenzene sulfonate, fluorine-containing alkyl carboxylates such as ammonium perfluorooctanoate and ammonium perfluorohexanoate, and a general formula F (CF ₂ ) _n. O (CF (X) CF ₂ O) _m CF (X) COOA (where X is a fluorine atom or a perfluoroalkyl group having 1 to 3 carbon atoms, A is a hydrogen atom, alkali metal or NH ₄ , n is An integer of 2 to 10, m is an integer of 0 or 1 to 3) is preferred.

As the fluorine-containing emulsifier represented by F (CF ₂ ) _n O (CF (X) CF ₂ O) _m CF (X) COOA, F (CF ₂ ) ₃ O (CF (CF ₃ ) CF ₂ O) ₂ CF (CF ₃ ) COONH ₄ , F (CF ₂ ) ₃ OCF ₂ CF ₂ OCF ₂ COONH ₄ , F (CF ₂ ) ₂ O (CF ₂ CF ₂ O) ₂ CF ₂ COONH ₄ , F (CF ₂ ) ₂ OCF ₂ CF ₂ OCF ₂ COONH ₄ , F (CF ₂ ) ₃ O (CF ₂ CF ₂ O) ₂ CF ₂ COONH ₄ , F (CF ₂ ) ₄ OCF ₂ CF ₂ OCF ₂ COONH ₄ , F (CF ₂ ) ₄ O _{(CF 2 CF 2 O) 2} CF 2 COONH 4, F (CF 2) 2 OCF 2 CF 2 OCF 2 COONa, F (CF 2) 2 O (CF 2 CF 2 O) 2 CF 2 COONa, _{(CF 2) 3 OCF 2 CF} 2 OCF 2 COONa, F (CF 2) 3 O (CF 2 CF 2 O) 2 CF 2 COONa, F (CF 2) 4 OCF 2 CF 2 OCF 2 COONa, F (CF 2 ) ₄ O (CF ₂ CF ₂ O) ₂ CF ₂ COONa and the like.

As emulsifiers, ammonium perfluorooctanoate, F (CF ₂ ) ₄ OCF ₂ CF ₂ OCF ₂ COONH ₄ , F (CF ₂ ) ₃ OCF ₂ CF ₂ OCF ₂ COONH ₄ and F (CF ₂ ) ₂ OCF ₂ CF ₂ OCF ₂ COONH ₄ is more preferred.
0.01-15 mass parts is preferable with respect to 100 mass parts of an aqueous medium, and, as for content of an emulsifier, 0.1-10 mass parts is more preferable.

  The radical polymerization initiator used in the emulsion polymerization is preferably a water-soluble initiator, and specific examples thereof include persulfates such as ammonium persulfate, hydrogen peroxide, disuccinic acid peroxide, azobisisobutylamidine disulfide. Organic initiators such as hydrochlorides, redox initiators consisting of a combination of persulfates or hydrogen peroxide and reducing agents such as sodium hydroxymethanesulfinate, sodium bisulfite, sodium thiosulfate, and a small amount of iron Inorganic initiators in which a ferrous salt, silver sulfate and the like are allowed to coexist. Preferred is ammonium persulfate / sodium hydroxymethanesulfinate / ferrous sulfate, and it is more preferable to add ethylenediaminetetraacetic acid disodium salt as a chelating agent to this system. The content of the polymerization initiator is preferably 0.0001 to 3% by mass, more preferably 0.001 to 1% by mass with respect to the monomer used for copolymerization.

Chain transfer agents include alcohols such as methanol, ethanol and propanol, and chlorofluoros such as 1,3-dichloro-1,1,2,2,3-pentafluoropropane and 1,1-dichloro-1-fluoroethane. Hydrocarbon, hydrocarbon such as pentane, hexane, cyclohexane, R ^f2 I ₂ (wherein R ^f2 is a saturated polyfluoroalkylene group having 1 to 16 carbon atoms), R ^f3 IBr (wherein R ^f3 is a carbon atom) Examples thereof include saturated polyfluoroalkylene groups of 1 to 16. As R ^f2 I ₂ , 1,4-diiodoperfluorobutane is preferable. Further, as R ^f3 IBr, 1-bromo-4-iodoperfluorobutane is preferable. When the aqueous medium contains a water-soluble organic solvent, the water-soluble organic solvent may function as a chain transfer agent.

Polymerization conditions such as polymerization pressure and temperature are appropriately selected depending on the monomer composition, the decomposition temperature of the radical polymerization initiator, and the like. Usually, the polymerization pressure is preferably from 0.1 to 20 MPaG, more preferably from 0.3 to 10 MPaG, most preferably from 0.3 to 5 MPaG. The polymerization temperature is preferably 0 to 100 ° C, more preferably 10 to 90 ° C, and most preferably 20 to 80 ° C.
The latex of the fluorinated elastic copolymer obtained by the emulsion polymerization is aggregated by a known method to isolate the fluorinated elastic copolymer. For aggregation, methods such as addition of a metal salt, addition of an inorganic acid such as hydrochloric acid, mechanical shearing, freezing and thawing are used.

The fluorine-containing elastic copolymer composition of the present invention contains (B) an unsaturated polyfunctional compound.
The unsaturated polyfunctional compound of component (B) can increase the crosslinking efficiency. Specific examples of the unsaturated polyfunctional compound of component (B) include, for example, triallyl cyanurate, triallyl isocyanurate, triallyl isocyanurate oligomer, trimethallyl isocyanurate, 1,3,5-triacryloylhexahydro -1,3,5-triazine, triallyl trimellitate, m-phenylenediamine bismaleimide, p-quinone dioxime, p, p'-dibenzoylquinone dioxime, dipropargyl terephthalate, diallyl phthalate, N, N ' , N ″, N ″ ′-tetraallyl terephthalamide, polymethylvinylsiloxane, polymethylphenylvinylsiloxane, and other vinyl group-containing siloxane oligomers.

Of these, triallyl cyanurate, triallyl isocyanurate, and trimethallyl isocyanurate are particularly preferable, and triallyl isocyanurate is more preferable.
(B) The unsaturated polyfunctional compound of a component may be used individually by 1 type, and may be used in combination of 2 or more type.
(B) 0.1-10 mass parts is preferable with respect to 100 mass parts of fluorine-containing elastic copolymers, and, as for content of the unsaturated polyfunctional compound of a component, 0.5-7 mass parts is more preferable. Within this range, crosslinked rubber properties with a good balance between strength and elongation can be obtained.

Component (C) in the fluorinated elastic copolymer composition of the present invention is at least one selected from the group consisting of aliphatic amines and monovalent metal salts of aliphatic carboxylic acids. By containing the component (C), the fluorinated elastic copolymer composition is excellent in molding processability and can give a crosslinked product having excellent physical properties.
The aliphatic amine may be either a saturated or unsaturated aliphatic amine, and is preferably an aliphatic monoamine. 14-20 are preferable and, as for carbon number of an aliphatic amine, 16-20 are especially preferable.
Specific examples of the aliphatic amine include monoalkyl primary amines, dimethylalkyl tertiary amines, and methyldialkyl tertiary amines, and preferably octadecylamine.
An aliphatic amine may be used individually by 1 type, and may be used in combination of 2 or more type.

The monovalent metal salt of the aliphatic carboxylic acid may be either a monovalent metal salt of a saturated or unsaturated aliphatic carboxylic acid, and is preferably a monovalent metal salt of an aliphatic monocarboxylic acid. 14-20 are preferable and, as for carbon number of aliphatic carboxylic acid, 16-20 are especially preferable. Examples of the monovalent metal include alkali metals such as lithium, sodium, potassium, rubidium, and cesium.
Specific examples of the monovalent metal salt of aliphatic carboxylic acid include sodium stearate and potassium stearate.
The monovalent metal salt of aliphatic carboxylic acid may be used alone or in combination of two or more.

Moreover, although the monovalent metal salt of an aliphatic amine and aliphatic carboxylic acid may be used independently, respectively, it is preferable to use both together. When both are used in combination, the Mooney viscosity of the fluorinated elastic copolymer composition of the present invention can be further reduced.
When both are used together, the mixing ratio of both is preferably in the range of 90/10 to 10/90, more preferably in the range of 80/20 to 20/80, and in the range of 70/30 to 30/70. Particularly preferred.
(C) 0.1-10 mass parts is preferable with respect to 100 mass parts of a fluorine-containing elastic copolymer, and, as for content of a component, 0.5-5 mass parts is more preferable. Within this range, cross-linked rubber properties with excellent fluidity during molding and excellent balance between strength and elongation can be obtained.

The fluorinated elastic copolymer composition of the present invention may contain a crosslinking agent.
As the crosslinking agent, organic peroxides, polyols, amine compounds, and the like are used, and organic peroxides that are particularly excellent in productivity, heat resistance, and chemical resistance of the crosslinked rubber are preferable.
The organic peroxide of component (D) in the present invention is an organic peroxide having a —O—O— bond, and specific examples thereof include ditert-butyl peroxide, tert-butylcumyl peroxide, and dicumyl. Peroxide, α, α′-bis (tert-butylperoxy) -diisopropylbenzene, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, 2,5-dimethyl-2,5- Dialkyl peroxides such as di (tert-butylperoxy) hexane-3, 1,1-di (tert-butylperoxy) -3,3,5-trimethylcyclohexane, 2,5-dimethylhexane-2,5 -Dihydroxy peroxide, benzoyl peroxide, tert-butyl peroxybenzene, 2,5-dimethyl-2,5-di (benzoyl peroxide) Oxy) hexane, tert- butylperoxy maleic acid, tert- butylperoxy isopropyl carbonate. Of these, dialkyl peroxides are preferred.

The content of the organic peroxide is preferably 0.3 to 10 parts by mass, more preferably 0.3 to 5 parts by mass, and 0.5 to 3 parts by mass with respect to 100 parts by mass of the fluorinated elastic copolymer. Part is most preferred. Within this range, a crosslinked rubber having an excellent balance between tensile strength and elongation can be obtained.
The fluorinated elastic copolymer composition of the present invention may appropriately contain compounding agents such as a reinforcing material, a filler, and an additive. Examples of the reinforcing material and filler include rubber reinforcing materials and fillers that are conventionally used in the production of crosslinked rubber, such as carbon black and white carbon such as channel black, furnace black, acetylene black, and thermal black. , Inorganic fillers such as magnesium carbonate, surface treated calcium carbonate, inorganic fillers such as calcium carbonate, clay, talc, silica, diatomaceous earth, alumina, barium sulfate, and other fillers. Examples thereof include additives such as pigments, antioxidants, stabilizers, processing aids, and internal mold release agents. A reinforcing material, a filler, and an additive may each be used individually by 1 type, and may be used in combination of 2 or more type.

The blending amount of the reinforcing material may be appropriately selected, but is preferably 1 to 100 parts by mass with respect to 100 parts by mass of the fluorinated elastic copolymer. The blending amount of the filler may be appropriately selected, but is preferably 1 to 100 parts by mass with respect to 100 parts by mass of the fluorinated elastic copolymer.
In addition, the fluorinated elastic copolymer composition of the present invention may be blended with one or more of other fluororubbers, EPDM, silicone rubber, acrylic rubber, other rubbers, and resins such as fluororesins. .

  In producing the fluorinated elastic copolymer composition of the present invention, at least selected from the group consisting of fluorinated elastic copolymers, unsaturated polyfunctional compounds, aliphatic amines and monovalent metal salts of aliphatic carboxylic acids. It is desirable to mix one kind and compounding agents such as organic peroxide, fluororubber, other reinforcing materials, fillers and additives sufficiently uniformly. Such mixing can be performed by a rubber kneading roll, a kneader, a Banbury mixer or the like that is generally used. The working conditions at the time of mixing are not particularly limited. Usually, the compounding agent can be sufficiently dispersed and mixed in the fluorinated elastic copolymer by kneading at a temperature of about 30 to 80 ° C. for about 10 to 60 minutes. Further, such a compounding agent can be dissolved and dispersed in a suitable solvent to form a suspension solution. Furthermore, so-called wet mixing is also possible, in which mixing is initially carried out in the medium. In such a case, a solution-like composition can be obtained by using a mixer such as a roll, a ball mill, or a homogenizer. The working conditions and operations during mixing are preferably performed by selecting optimum conditions according to the type and purpose of the raw materials and compounding agents used.

The fluorinated elastic copolymer composition of the present invention can be produced by a molding process such as extrusion, transfer, calender, roll coat, brush coating, impregnation, etc. in addition to normal mold molding, sealing, packing, sheet, pipe, It can be molded into molded products such as rods, tubes, angles, channels, draw cloths, and coated plates, and can also be molded into irregular shaped products and special molded products such as sponge rubber by various other molding methods. To get.
The fluorinated elastic copolymer composition of the present invention thus molded can be made into a crosslinked product by a crosslinking means as described later.

In the present invention, the crosslinking is preferably crosslinking by heating, crosslinking by radiation irradiation, or the like. Examples of radiation to be irradiated include γ rays, electron beams, and ultraviolet rays.
As the operation for performing the crosslinking, a conventionally used operation can be adopted.
As the crosslinking by heating, for example, an operation of heating while pressing in a mold may be employed, and an operation of heating in a heating furnace or a steam kettle after molding by extrusion, calender roll or the like may be employed. As for the working conditions at the time of crosslinking, it is desirable to select the optimum conditions according to the raw materials used and the composition.

The temperature at the time of heat crosslinking is usually about 60 to 250 ° C, preferably about 120 to 200 ° C. The heating time is not particularly limited, but when blending an organic peroxide, it is in the range of 1 minute to 3 hours, preferably in the range of 5 minutes to 2 hours, depending on the type of organic peroxide. Is done. If the heating temperature is increased, the heating time can be shortened. In addition, the reheating process of the crosslinked material obtained can also be employ | adopted and it is useful for the improvement of a physical property. For example, a reheating treatment of about 2 to 25 hours at a temperature of 150 to 250 ° C., preferably 180 to 230 ° C. may be employed. Note that the reheating treatment is also called secondary crosslinking.

  In the heat crosslinking when an organic peroxide is blended, at least one selected from the group consisting of unsaturated polyfunctional compounds, aliphatic amines and monovalent metal salts of aliphatic carboxylic acids is added to the fluorinated elastic copolymer. When the composition containing the organic peroxide is heated, the organic peroxide crosslinking proceeds by the unsaturated bond and the unsaturated bond of the unsaturated polyfunctional compound in the fluorinated elastic copolymer. It is considered a thing. Here, the fluorinated elastic copolymer has a higher activity for the crosslinking reaction by blending at least one selected from the group consisting of aliphatic amines and monovalent metal salts of aliphatic carboxylic acids, It is presumed that the organic peroxide cross-linking effectively proceeds and the heat resistance, oil resistance and chemical resistance of the resulting cross-linked product are also improved.

As a preferred specific example of the radiation irradiation crosslinking, a suspension solution in which the fluorinated elastic copolymer composition of the present invention is dissolved and dispersed in an appropriate solvent is formed by coating and drying, and then irradiated with radiation. And those obtained by extruding and irradiating the fluorinated elastic copolymer composition of the present invention.
The conditions for coating and forming for radiation irradiation crosslinking are not particularly limited, but may be usually performed at around room temperature, and the drying temperature is not particularly limited, but is preferably 40 to 100 ° C.
The conditions for the molding temperature of the molded article for radiation irradiation crosslinking may be appropriately selected according to the molding method, but the conditions for extrusion molding for radiation irradiation crosslinking are not particularly limited, but are preferably 50 ° C to 250 ° C. 70 ° C to 230 ° C is particularly preferable.
Although the irradiation amount in irradiation of a gamma ray and an electron beam should just be selected suitably, 0.1-30 Mrad is preferable and 1-20 Mrad is preferable.

  In radiation irradiation cross-linking, a composition containing at least one selected from the group consisting of unsaturated polyfunctional compounds and aliphatic amines and monovalent metal salts of aliphatic carboxylic acids in a fluorine-containing elastic copolymer is used. Irradiation is considered to cause crosslinking to proceed due to the unsaturated bond in the fluorinated elastic copolymer and the unsaturated bond of the unsaturated polyfunctional compound. Here, the fluorinated elastic copolymer has a higher activity for the crosslinking reaction by blending at least one selected from the group consisting of aliphatic amines and monovalent metal salts of aliphatic carboxylic acids, It is presumed that cross-linking proceeds effectively and that the resulting cross-linked product also has good heat resistance, oil resistance and chemical resistance.

  EXAMPLES The present invention will be specifically described below based on examples, but the present invention is not limited to these. In the examples, “parts” means “parts by mass”.

(Polymer 1: Production of fluorinated elastic copolymer (TFE / P / vinyl crotonic acid copolymer))
After degassing a 3200 mL stainless steel pressure-resistant reactor equipped with a stirring anchor blade, 1600 g of ion exchange water, 40 g of disodium hydrogen phosphate dodecahydrate, 0.5 g of sodium hydroxide, 97 g of Tert-butanol, 9 g sodium lauryl sulfate, 2.5 g ammonium persulfate were added. Furthermore, an aqueous solution in which 0.4 g of ethylenediaminetetraacetic acid disodium salt dihydrate (hereinafter referred to as EDTA) and 0.3 g of ferrous sulfate heptahydrate was previously dissolved in 200 g of ion-exchanged water was added. did. Then, a monomer mixed gas of TFE / P = 85/15 (molar ratio) was injected at 40 ° C. so that the internal pressure of the reactor became 2.5 MPaG. The anchor blade was rotated at 300 rpm, and a 2.5 mass% aqueous solution of sodium hydroxymethanesulfinate dihydrate (hereinafter also referred to as Rongalite) was added to initiate the polymerization reaction.

  Since the pressure decreases as the polymerization proceeds, when the reactor internal pressure drops to 2.49 MPa, a mixed gas of TFE / P = 56/44 (molar ratio) is injected, and the reactor internal pressure is increased to 2.51 MPaG. The pressure was increased. This was repeated and the internal pressure of the reactor was maintained at 2.49 to 2.51 MPaG, and the polymerization reaction was continued. When the added amount of the TFE / P mixed gas reached 50 g, 4 mL of a 5 mass% tert-butanol solution of vinyl crotonate was injected into the reactor. Thereafter, 4 mL of a tert-butanol solution of vinyl crotonate was injected every 20 g until the amount of TFE / P mixed gas added was 330 g. When the total amount of the TFE / P mixed gas reached 400 g, the addition of the Rongalite aqueous solution was stopped, the reactor internal temperature was cooled to 10 ° C., the polymerization reaction was stopped, and TFE / P / vinyl crotonate was stopped. A copolymer latex was obtained. The amount of Rongalite aqueous solution used was 23 g. The polymerization time was about 3.5 hours.

The latex was added to a 5% by mass aqueous solution of calcium chloride, and the latex was aggregated by salting out to obtain a TFE / P / vinyl crotonate copolymer. The copolymer was collected by filtration, washed with ion-exchanged water, and dried in an oven at 120 ° C. for 12 hours to obtain 398 g of a white TFE / P / vinyl crotonate copolymer.
The composition of the copolymer was repeating unit based on TFE / repeating unit based on P / repeating unit based on vinyl crotonate = 55.3 / 44.7 / 0.17 (molar ratio). The Mooney viscosity MS1 + 4 (100 ° C.) was 81.

(Examples 1-4)
Using the fluorinated elastic copolymer (Polymer 1) produced above, according to the components and blending amounts shown in Table 1, various blending agents are uniformly mixed in 2 rolls to obtain a fluorinated elastic copolymer composition. Manufactured.
The compound Mooney viscosity of these fluorinated elastic copolymer compositions was determined by using an L-shaped rotor having a diameter of 38.1 mm and a thickness of 5.54 mm in accordance with JIS K6300, at 121 ° C., and with a preheating time of 1 minute. ML1 + 4 (121 ° C.) and ML1 + 10 (121 ° C.) measured by setting the time to 4 minutes or 10 minutes, respectively.
Further, these fluorinated elastic copolymer compositions were measured for crosslinking properties under a condition of an amplitude of 3 degrees at 177 ° C. for 12 minutes using a crosslinking property measuring machine (RPA, manufactured by Alpha Technologies). These fluorinated elastic copolymer compositions were press-crosslinked at 170 ° C. for 20 minutes, and then secondary-crosslinked in an oven at 200 ° C. for 4 hours to obtain a crosslinked rubber.
In the crosslinking characteristics, MH indicates the maximum value of torque, ML indicates the minimum value of torque, MH-ML indicates the rack strength (also referred to as vulcanization degree), t10 indicates the approximate value of the scorch time, and t90 Indicates an approximate value of the optimum crosslinking time.

( Comparative Examples 1 to 4 )
According to the components and blending amounts shown in Table 2, an elastic composition was produced in the same manner as in Example 1, and the crosslinking properties were measured using a crosslinking property measuring machine.
The basic physical properties and molding processability of the crosslinked rubbers obtained in Examples and Comparative Examples were measured according to JIS K6351 and JIS K6253. The results are shown in Table 1.
The term “impossible to mold” means that the crosslinked rubber sheet used for the physical property measurement test of the crosslinked rubber was not obtained due to insufficient crosslinking.

The name of each compounding component in the table indicates the following.
Polymer 1: Preparation Example by resulting TFE / P / vinyl crotonate copolymer TAIC: (manufactured by Nippon Kasei Chemical Co.) triallyl isocyanurate
Armin 18D: Stearylamine (manufactured by Lion Akzo Co., Ltd.)
Parkadox 14: α, α′-bis (t-butylperoxy) -diisopropylbenzene (manufactured by Kayaku Akzo Co., Ltd.)
Perhexa 25B: 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane (manufactured by NOF Corporation)
Kyowa Mug # 150: Magnesium oxide (manufactured by Kyowa Chemical Industry Co., Ltd.)
MT carbon: carbon black

The fluorinated elastic copolymer compositions of Examples 1 to 3 have a low maximum Mooney viscosity, an excellent fluidity of the composition, a large maximum torque MH without inhibiting the crosslinking reaction, and a minimum torque. The ML was small, the times of t10 and t90 were short, and the crosslinking reactivity such as high crosslinking speed was excellent, and excellent physical properties of the crosslinked rubber were exhibited.
On the other hand, the fluorinated elastic copolymer composition of Comparative Example 1 containing no aliphatic amine and no aliphatic metal salt has a high Mooney viscosity, poor fluidity, a large minimum torque ML, and a crosslinking. The reactivity was poor. In addition, the fluorinated elastic copolymer composition of Comparative Example 2 in which an aliphatic amine and an aliphatic metal salt are not blended and a divalent metal oxide and a hydroxide are blended further has a Mooney viscosity of the composition. It was high, the fluidity was even worse, the minimum torque ML was large, and the crosslinking reactivity was poor.

In addition, the fluorine-containing elastic copolymer composition of Comparative Example 3 in which an aliphatic amine and an aliphatic metal salt were not blended, but stearic acid was blended instead, had poor crosslinking reactivity and could not be molded. In addition, the fluorinated elastic copolymer composition of Comparative Example 4 in which an aliphatic amine and an aliphatic metal salt were not blended, but zinc stearate was blended instead, had a high Mooney viscosity and the composition flowed. The nature was bad .

  Molding processability was measured using the compositions obtained in Examples 1 to 3 and Comparative Example 2. Molding processability (rubber flowability) with a spiral mold was measured using a vertical injection molding machine. A spiral mold is a mold having a hemispherical cross section with graduated marks at regular intervals, and a spiral groove formed in the outer side from the mold center. By measuring to which scale the rubber has flowed using this mold, the moldability can be determined. In addition, using the compositions obtained in Examples 1 to 3 and Comparative Example 2, a sheet having a thickness of 0.5 mm was dispensed with two rolls to confirm shrinkage and smoothness. Furthermore, the tube was extruded using an extruder, and the surface smoothness was confirmed. The results are shown in Tables 1 and 2.

  The fluorine-containing elastic copolymer compositions of Examples 1 to 3 were compared with the fluorine-containing elastic copolymer composition of Comparative Example 2 in which an aliphatic amine and an aliphatic metal salt were not blended. It showed good flowability. Further, even if the thin sheet was dispensed with a roll, it was smooth with little shrinkage. Furthermore, even if the tube was extruded, a smooth surface was obtained.

The present invention provides a fluorinated elastic copolymer composition excellent in fluidity during molding and a crosslinked rubber obtained by crosslinking the composition, and the industrial benefits thereof are extremely great. Furthermore, the specific cross-linked rubber of the present invention is based on various excellent cross-linking properties, such as O-ring, X-shape / V-shaped cross section ring, sheet, gasket, oil seal, damper, diaphragm, hose, tube, etc. Used for. In particular, it is excellent in applicability to molded products having complicated shapes. In addition, the crosslinked rubber of the present invention is a heat- and chemical-resistant sealing material, a wire coating material, a sealing material for semiconductors and liquid crystal manufacturing equipment, a conveying material and a cushion material, a corrosion-resistant rubber paint, a similar part such as a food or chemical plant. It is extremely useful in a wide range of applications such as.

Claims (10)

(A) tetrafluoroethylene, hexafluoropropylene, vinylidene _{fluoride, CF 2 = CF-O-} R f ( wherein, ^{R f} is a saturated perfluoroalkyl group or a perfluoro (alkoxyalkyl having 1 to 8 carbon atoms) A repeating unit (1) based on one or more fluorine-containing monomers selected from the group consisting of perfluorovinyl ethers represented by the general formula CR ¹ R ² = CR ³ COOCH = CH ₂ (formula Wherein R ¹ and R ² are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms or an alkoxyalkyl group having 1 to 10 carbon atoms including an etheric oxygen atom, and R ³ is a hydrogen atom , a fluorine atom or a methyl group.) in the fluorine-containing bullets containing repeating units (m) based on vinyl ester monomer represented A fluorine-containing copolymer, (B) an unsaturated polyfunctional compound, and (C) at least one selected from the group consisting of aliphatic amines and monovalent metal salts of aliphatic carboxylic acids Elastic copolymer composition. (A) is further ethylene, propylene, general formula CH ₂ = CH-O-R ⁴ (Wherein R ⁴ Is a C1-C8 saturated alkyl or alkoxyalkyl group. The fluorine-containing elastic copolymer composition according to claim 1, which is a fluorine-containing elastic copolymer containing a repeating unit (n) based on one or more hydrocarbon monomers selected from the group consisting of vinyl ethers represented by object. The fluorine-containing elasticity according to claim 1 or 2 , wherein the content ratio of the repeating unit in (A) is (m) / ((l) + (n)) = 0.0001 to 0.1 (molar ratio). Copolymer composition. The fluorine-containing elastic copolymer composition according to any one of claims 1 to 3, wherein a monovalent metal salt of an aliphatic amine and an aliphatic carboxylic acid is used in combination as the (C). Furthermore, (D) the fluorine-containing elastic copolymer composition in any one of Claims 1-4 containing the organic peroxide. The fluorine-containing elasticity according to any one of claims 2 to 5 , wherein a content ratio of the repeating unit (n ) in (A) is (n) / (l) = 1/99 to 70/30 (molar ratio). Copolymer composition. The fluorine-containing elastic copolymer composition according to any one of claims 1 to 6 , wherein R ² and R ³ in the vinyl ester monomer are hydrogen atoms. The fluorinated elastic copolymer composition according to any one of claims 1 to 6 , wherein the vinyl ester monomer is vinyl crotonate. The fluorine-containing monomer is tetrafluoroethylene, the hydrocarbon monomer is propylene, and (n) / (l) = 40/60 to 60/40 (molar ratio), (m) / ((l) + (n)) = 0.0001~0.05 (molar ratio) fluorinated elastic copolymer composition according to any one of claims 2-8 is.   A crosslinked rubber obtained by crosslinking the fluorinated elastic copolymer composition according to claim 1.