JP7111943B2 - Complicated shape molding with fluororubber layer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a complex-shaped molded article having a fluororubber layer.

Rubber moldings having a complicated shape, such as primer valves, flexible joints and expansion joints having a bellows structure, boots, grommets, etc., are usually made by heating a rubber composition in a mold corresponding to the complicated shape to crosslink and are molding.

Fluororubber is known to be excellent in chemical resistance, oil resistance, and heat resistance (for example, Patent Documents 1 to 4).

JP-A-60-55050 JP-A-9-124871 JP 2013-216915 A WO2012-026556

An object of the present invention is to provide a complex-shaped molded article having a fluororubber layer excellent in bending fatigue resistance, tear strength and amine resistance.

The present invention has a crosslinked fluororubber layer obtained by crosslinking a composition containing a fluorine-containing copolymer having a glass transition temperature of 25° C. or lower,
The fluorine-containing copolymer includes vinylidene fluoride and the following general formula (1):
_CH2 =CFRf (1)
(In the formula, Rf is a linear or branched fluoroalkyl group having 1 to 12 carbon atoms.)
A complex-shaped molded article characterized by being a copolymer comprising a fluorine-containing monomer (1) represented by:

The fluoropolymer includes vinylidene fluoride and the following general formula (1):
_CH2 =CFRf (1)
(In the formula, Rf is a linear or branched fluoroalkyl group having 1 to 12 carbon atoms.)
A copolymer consisting of a fluoromonomer (1) represented by and other monomers copolymerizable therewith, wherein the molar ratio of vinylidene fluoride units/fluoromonomer (1) units is It is preferably 85/15 to 20/80, and other monomeric units are preferably 0 to 50 mol % of the total monomeric units.

It is preferred that the composition comprises a cross-linking agent.
Preferably, the cross-linking agent is an organic peroxide and the composition comprises a multifunctional co-cross-linking agent.

It is preferably at least one member selected from the group consisting of bellows structure moldings, joint members, boots, grommets, primer bulbs, and diaphragm members.

ADVANTAGE OF THE INVENTION According to this invention, the complex-shaped molded object which has a fluororubber layer excellent in bending fatigue resistance, tear strength, and amine resistance can be provided.

FIG. 2 is a schematic cross-sectional view of a mold used for producing a complex-shaped molded article of an example. FIG. 4 is a schematic diagram showing an example of the shape of a primer bulb;

The present invention has a crosslinked fluororubber layer obtained by crosslinking a composition containing a fluorine-containing copolymer having a glass transition temperature of 25° C. or lower,
The fluorine-containing copolymer includes vinylidene fluoride and the following general formula (1):
_CH2 =CFRf (1)
(In the formula, Rf is a linear or branched fluoroalkyl group having 1 to 12 carbon atoms.)
It relates to a complex-shaped molded article characterized by being a copolymer comprising a fluorine-containing monomer (1) represented by:

Rubber moldings with complex shapes, such as primer bulbs, are sometimes used in environments where they are deformed by bending and in contact with various chemical solutions containing amine compounds. It is desired to provide a molded article having a rubber layer with excellent amine properties. As a result of intensive studies, the present inventors have found that a crosslinked fluororubber layer obtained by crosslinking a composition containing a specific fluorocopolymer is excellent in flex fatigue resistance, tear strength and amine resistance. , the inventors have found that the molded article having the crosslinked fluororubber layer is suitable for the molded article having the complicated shape, and have arrived at the present invention.

The complex-shaped molded article of the present invention has a crosslinked fluororubber layer obtained using a copolymer consisting of vinylidene fluoride and the fluorine-containing monomer (1) represented by the above general formula (1), It has excellent bending fatigue resistance, tear strength and amine resistance. In addition, the complex-shaped molded article is also excellent in releasability.

Here, the complicated-shaped molded article means a molded article having a complicated-shaped portion having a crosslinked fluororubber layer. A complicated shape part means, for example, a convex part.
The complex-shaped molded body is preferably a molded body having one or more (or two or more) protrusions. More preferably, it is a molded body having one or more projections projecting in the outer peripheral direction of the cylinder.
Examples of complex-shaped moldings include bellows structure moldings and primer bulbs.
The bellows structure is, for example, a structure having ridges or troughs or both in the outer peripheral direction of a cylinder, and the shape of the ridges or troughs may be an arcuate wavy shape or a triangular wavy shape. One of the preferred forms of the complex-shaped molded article of the present invention is a bellows-structured molded article from the viewpoint of being excellent in releasability during molding.
The primer valve is a pump that sends fuel to the carburetor (float chamber of the carburetor) in advance so that the engine can be easily started. The primer bulb has, for example, one ridge in the outer peripheral direction of the cylinder, and the shape of the ridge is an arcuate wavy shape. The shape of the primer bulb is, for example, the shape shown in FIG.
The complex-shaped molded article of the present invention can be used for any of primer bulbs for automobiles, primer bulbs for ships, primer bulbs for aircraft, primer bulbs for construction machinery, primer bulbs for agricultural machinery, and primer bulbs for mining machinery. For example, it is particularly useful as a marine primer bulb.

The fluorine-containing copolymer includes vinylidene fluoride and the following general formula (1):
_CH2 =CFRf (1)
(In the formula, Rf is a linear or branched fluoroalkyl group having 1 to 12 carbon atoms.)
(a copolymer containing vinylidene fluoride and a polymerized unit based on the above general formula (1)) composed of a fluorine-containing monomer (1) represented by:

The above fluorine-containing copolymer exhibits an extremely low glass transition temperature due to the above specific configuration. The fluorine-containing copolymer is excellent in bending fatigue resistance and tear strength. Further, the fluorine-containing copolymer containing units of the fluorine-containing monomer (1) represented by the general formula (1) is difficult to dehydrofluoride, and is excellent in amine resistance, oil resistance and low temperature resistance. It also has a fast vulcanization rate and good processability. Furthermore, it is also excellent in steam resistance.
The fluorine-containing copolymer is preferably a fluorine-containing elastomer, and is preferably an amorphous polymer.

The fluorine-containing copolymer has a glass transition temperature of 25° C. or lower. Also, the temperature can be set to 0° C. or lower. The glass transition temperature is preferably −5° C. or lower, more preferably −10° C. or lower. Furthermore, it is possible to set the temperature to -20°C or lower. Since the fluorine-containing copolymer has such an extremely low glass transition temperature, it is also excellent in low-temperature properties (cold resistance).
The glass transition temperature was measured by using a differential scanning calorimeter (X-DSC823e, manufactured by Hitachi Techno Science Co., Ltd.), and after cooling to -75°C, a DSC curve was obtained by heating 10 mg of the sample at a rate of 20°C/min. , and the temperature at which the extended line of the base line before and after the secondary transition of the DSC curve intersects with the tangent line at the inflection point of the DSC curve was defined as the glass transition temperature.

The fluorine-containing monomer represented by the above general formula (1) has excellent vulcanization properties, and the bending fatigue resistance, tear strength, amine resistance, fuel oil resistance and low temperature resistance of the resulting molded product. (1) is preferably a monomer in which Rf is a linear fluoroalkyl group, more preferably a monomer in which Rf is a linear perfluoroalkyl group. Rf preferably has 1 to 6 carbon atoms. As the fluorine-containing monomer (1) represented by the general formula (1), CH ₂ =CFCF ₃ , CH ₂ =CFCF ₂ CF ₃ , CH ₂ =CFCF ₂ CF ₂ CF ₃ , CH ₂ =CFCF ₂ 2,3,3,3 _- tetrafluoropropene represented by CH _{2 = CFCF 3 is} preferred among others.

The fluorine-containing copolymer may further contain polymerized units derived from monomers other than vinylidene fluoride and the fluorine-containing monomer (1) represented by formula (1).
The other monomer is not particularly limited as long as it is a monomer copolymerizable with vinylidene fluoride and the fluorine-containing monomer (1) represented by formula (1), and is one or more. may be used.

The above other monomers include tetrafluoroethylene [TFE], hexafluoropropylene, perfluoro(methyl vinyl ether), perfluoro(ethyl vinyl ether), perfluoro(propyl vinyl ether), chlorotrifluoroethylene, trifluoroethylene, hexafluoroethylene It is preferably at least one selected from the group consisting of fluoroisobutene, vinyl fluoride, ethylene, propylene, alkyl vinyl ether, and a monomer that provides a cross-linking site, TFE, hexafluoropropylene, perfluoro(methyl vinyl ether ), perfluoro(ethyl vinyl ether), perfluoro(propyl vinyl ether), chlorotrifluoroethylene, trifluoroethylene, hexafluoroisobutene, vinyl fluoride, ethylene, alkyl vinyl ether, and a group consisting of a monomer that provides a cross-linking site At least one more selected is more preferable. More preferred is TFE. Being only TFE is also one of the preferred forms.

In the fluorine-containing copolymer, the monomer that provides the cross-linking site includes, for example, the general formula:
CX ¹ ₂ =CX ¹ -Rf ¹ CHR ¹ X ²
(wherein X ¹ is a hydrogen atom, a fluorine atom or —CH ₃ , Rf ¹ is a fluoroalkylene group, a perfluoroalkylene group, a fluoro(poly)oxyalkylene group or a perfluoro(poly)oxyalkylene group, R ¹ is a hydrogen atom or —CH ₃ , X ² is an iodine atom or a bromine atom.), an iodine- or bromine-containing monomer (preferably an iodine-containing monomer) represented by the general formula:
CF ₂ =CFO(CF ₂ CF(CF ₃ )O) _m (CF ₂ ) _n −X ³
(Wherein, m is an integer of 0 to 5, n is an integer of 1 to 3, X ³ is a cyano group, a carboxyl group, an alkoxycarbonyl group, an iodine atom, or a bromine atom.) body, general formula:
_CH2 = _CFCF2O (CF( _CF3 ) _CF2O ) _m (CF( _CF3 )) _n ^- X4
(Wherein, m is an integer of 0 to 5, n is an integer of 1 to 3, and X ⁴ is a cyano group, a carboxyl group, an alkoxycarbonyl group, an iodine atom, a bromine atom, or —CH ₂ OH.) and the monomer represented.

Among others, CF2 _{= CFOCF2CF ( CF3} ) _OCF2CF2CN , CF2 _{= CFOCF2CF ( CF3} ) _OCF2CF2COOH , CF2 _{= CFOCF2CF2CH2I} , _{CF2 = CFOCF} 2CF( _CF3 ) _OCF2CF2CH2I , _{CH2 = CFCF2OCF} ( _CF3 ) _CF2OCF ( _CF3 )CN, _{CH2 = CFCF2OCF} ( _CF3 ) _{CF2OCF ( CF3} ) It is preferably at least one selected from the group consisting of COOH and _CH2 = _CFCF2OCF ( _CF3 ) _CF2OCF ( _CF3 ) _CH2OH .
As the monomer that provides the cross-linking site, CF ₂ =CFOCF ₂ CF ₂ CH ₂ I can improve the cross-linking density and improve the compression set in the cross-linking using peroxide. Especially preferred.
In addition, monomers exemplified as monomers that provide a cross-linking site in the copolymer (III) described later can also be suitably used.

In the fluorine-containing copolymer, the molar ratio of vinylidene fluoride units/fluoromonomer (1) units represented by formula (1) is preferably 87/13 to 20/80. The molar ratio of vinylidene fluoride units/fluorine-containing monomer (1) units represented by formula (1) is preferably 22/78 or more, more preferably 50/50 or more, and 60/ It is more preferably 40 or more. Further, other monomer units are preferably 0 to 50 mol %, more preferably 1 to 40 mol %, of the total monomer units.

The fluorine-containing copolymer is preferably a copolymer comprising polymerized units based on vinylidene fluoride, the fluorine-containing monomer (1) represented by general formula (1), and other monomers.

The fluorine-containing copolymer may contain at least one of an iodine atom and a bromine atom. In particular, those containing iodine are preferred. In that case, the total content of iodine atoms and bromine atoms is preferably 0.001 to 10% by mass.

Since the vulcanization properties and the bending fatigue resistance, tear strength, amine resistance, fuel oil resistance, and low temperature resistance of the resulting molded product are excellent, the above fluorine-containing copolymers are vinylidene fluoride and fluorine-containing monomers. a copolymer (I) consisting of a monomer (1) and having a molar ratio of vinylidene fluoride units/fluoromonomer (1) units of 87/13 to 22/78, vinylidene fluoride, and a fluorine-containing monomer (1), and vinylidene fluoride and other monomers copolymerizable with the fluoromonomer (1), wherein the molar ratio of vinylidene fluoride units/fluoromonomer (1) units is 85/15 to 20/80, a copolymer (II) in which other monomer units are 1 to 50 mol% of the total monomer units, and vinylidene fluoride, a fluorine-containing monomer (1 ), and vinylidene fluoride and another monomer copolymerizable with the fluorine-containing monomer (1), wherein the molar ratio of vinylidene fluoride unit/fluorine-containing monomer (1) unit is 85/15 ~ 20/80, the other monomer unit is 0 to 50 mol% of the total monomer units, has at least one of an iodine atom and a bromine atom (preferably an iodine atom), and has a content of It is preferably at least one selected from the group consisting of copolymer (III) with a total content of 0.001 to 10% by mass.

The copolymer (I) is composed of vinylidene fluoride and a fluorine-containing monomer (1) represented by formula (1), and vinylidene fluoride unit/fluorine-containing monomer represented by formula (1) (1) The unit molar ratio is from 87/13 to 22/78.
Since the vulcanization properties and the bending fatigue resistance, tear strength, amine resistance, fuel oil resistance and low temperature resistance of the resulting molded product are excellent, the above copolymer (I) is a vinylidene fluoride unit / formula It is preferable that the molar ratio of the fluorine-containing monomer (1) units represented by (1) is from 82/18 to 60/40.

The copolymer (II) includes vinylidene fluoride, a fluorine-containing monomer (1) represented by formula (1), and vinylidene fluoride and a fluorine-containing monomer represented by formula (1) ( 1) is a copolymer composed of polymerized units based on another monomer copolymerizable with 1), and the molar ratio of vinylidene fluoride units/fluorinated monomer (1) units represented by the formula (1) is 85/15 to 20/80, and other monomer units are 1 to 50 mol % of the total monomer units.
The copolymer (II) is excellent in vulcanization properties, and in bending fatigue resistance, tear strength, amine resistance, fuel oil resistance and low temperature resistance of the resulting molded product, the vinylidene fluoride unit / formula It is preferable that the molar ratio of the fluorine-containing monomer (1) units represented by (1) is from 85/15 to 50/50. More preferably, it is 85/15 to 60/40.

Since the vulcanization properties and the bending fatigue resistance, tear strength, amine resistance, fuel oil resistance and low temperature resistance of the resulting molded product are excellent, the above copolymer (II) contains other monomer units. is preferably 1 to 40 mol % of the total monomer units. As other monomers, those mentioned above are suitable.

The above copolymer (III) is vinylidene fluoride and the following general formula (1):
_CH2 =CFRf (1)
(Wherein, Rf is a straight or branched fluoroalkyl group having 1 to 12 carbon atoms.) A fluorine-containing monomer (1) represented by, and vinylidene fluoride and the fluorine-containing monomer ( 1) is a copolymer containing polymerized units based on other monomers copolymerizable with 1), and the molar ratio of vinylidene fluoride units/fluorinated monomer (1) units is 85/15 to 20/80. is, other monomer units are 0 to 50 mol% of the total monomer units, have at least one of an iodine atom and a bromine atom, and the total content is 0.001 to 10% by mass .

The above copolymer (III) is vinylidene fluoride and the following general formula (1):
_CH2 =CFRf (1)
(Wherein, Rf is a linear or branched fluoroalkyl group having 1 to 12 carbon atoms). Ride, the following general formula (1):
_CH2 =CFRf (1)
(Wherein, Rf is a straight or branched fluoroalkyl group having 1 to 12 carbon atoms.) A fluorine-containing monomer (1) represented by, and vinylidene fluoride and the fluorine-containing monomer ( It is preferably a copolymer composed of polymerized units based on other monomers copolymerizable with 1).
In this case, the copolymer (III) is a copolymer consisting essentially of vinylidene fluoride and a polymerized unit based on the fluorine-containing monomer (1) represented by the formula (1), or is a copolymer consisting of vinylidene fluoride, a fluorine-containing monomer (1) represented by the formula (1), and a polymerized unit based on the other monomer, but within a range that does not impair the effects of the present invention. and may be produced using a reactive emulsifier. Moreover, the I terminal etc. derived from a chain transfer agent may be included.

The above copolymer (III) is vinylidene fluoride and the following general formula (1):
_CH2 =CFRf (1)
(wherein Rf is a linear or branched fluoroalkyl group having 1 to 12 carbon atoms). More preferably, the molar ratio of lyde unit/fluorinated monomer (1) unit is 80/20 to 20/80.

The copolymer (III) also has a vinylidene fluoride unit/fluorine-containing monomer (1) unit molar ratio of 85/15 to 50/50, and other monomer units It is also preferably 1 to 50 mol % of the units.

The content of each monomer unit is a value measured by the NMR method.

The copolymer (III) contains at least one of an iodine atom and a bromine atom, and the total content thereof is 0.001 to 10% by mass. The total content of iodine atoms and bromine atoms is preferably 0.01 to 5% by mass, more preferably 0.1 to 5% by mass. From the viewpoint of vulcanization properties, the above copolymer (III) more preferably has an iodine atom.
The iodine content was measured by mixing 12 mg of the sample (fluoropolymer) with 5 mg of Na ₂ SO ₃ and mixing 20 ml of pure water with Na ₂ CO ₃ and K ₂ CO ₃ at a ratio of 1:1 (mass ratio). 30 mg of dissolved absorption liquid can be used, burned in oxygen in a quartz combustion flask, allowed to stand for 30 minutes, and then measured using a Shimadzu 20A ion chromatograph. As a calibration curve, a KI standard solution containing 0.5 ppm or 1.0 ppm of iodide ions can be used.

The bonding position of the iodine atom and the bromine atom may be the terminal of the main chain of the copolymer (III), the terminal of the side chain, or both. In such a copolymer, the iodine terminal or bromine terminal becomes a cross-linking point (cross-linking site), and a cross-linked fluorine-containing polymer with a high cross-linking density can be obtained, and peroxide cross-linking can be performed more easily. become.

The copolymer (III) uses iodine or a bromine-containing monomer (preferably an iodine-containing monomer) as a monomer that provides a cross-linking site, and uses a bromine compound or an iodine compound as a polymerization initiator or chain transfer agent. can be manufactured by using, and the like.

In the copolymer (III), other monomers are particularly limited as long as they are copolymerizable with vinylidene fluoride and the fluorine-containing monomer (1) represented by formula (1). However, one or two or more monomers may be used.

Other monomers in the copolymer (III) are preferably 0 to 50 mol % of the total monomer units. It is more preferably 1 to 50 mol %.

In the above copolymer (III), examples of the monomer that provides the cross-linking site include the general formula:
CX ¹ ₂ =CX ¹ -Rf ¹ CHR ¹ X ²
(wherein X ¹ is a hydrogen atom, a fluorine atom or —CH ₃ , Rf ¹ is a fluoroalkylene group, a perfluoroalkylene group, a fluoro(poly)oxyalkylene group or a perfluoro(poly)oxyalkylene group, R ¹ is a hydrogen atom or —CH ₃ , X ² is an iodine atom or a bromine atom.), an iodine- or bromine-containing monomer (preferably an iodine-containing monomer) represented by the general formula:
CX ¹ ₂ = CX ¹ - Rf ¹ X ²
(wherein X ¹ is a hydrogen atom, a fluorine atom or —CH ₃ , Rf ¹ is a fluoroalkylene group, a perfluoroalkylene group, a fluoro(poly)oxyalkylene group or a perfluoro(poly)oxyalkylene group, X ² is an iodine atom or a bromine atom) (preferably the general formula: CH ₂ ═CH(CF ₂ ) _n I (n is an integer of 2 to 8). ) iodine-containing monomer represented by), the general formula:
CF ₂ =CFO(CF ₂ CF(CF ₃ )O) _m (CF ₂ ) _n −X ³
(Wherein, m is an integer of 0 to 5, n is an integer of 1 to 3, X ³ is a cyano group, a carboxyl group, an alkoxycarbonyl group, an iodine atom, or a bromine atom.) body, general formula:
_CH2 = _CFCF2O (CF( _CF3 ) _CF2O ) _m (CF( _CF3 )) _n ^- X4
(Wherein, m is an integer of 0 to 5, n is an integer of 1 to 3, X ⁴ is a cyano group, a carboxyl group, an alkoxycarbonyl group, an iodine atom, a bromine atom or —CH ₂ OH.) A monomer with the general formula:
^CR2R3 = ^{CR4 -} Z ^{- CR5} = ^CR6R7
(Wherein, R ² , R ³ , R ⁴ , R ⁵ , R ⁶ and R ⁷ are the same or different and represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. Z is a linear or branched an alkylene group having 1 to 18 carbon atoms, a cycloalkylene group having 3 to 18 carbon atoms, and an at least partially fluorinated alkylene or oxyalkylene group having 1 to 10 carbon atoms, which may have an oxygen atom in the form of , or
-(Q) _p -CF ₂ O-(CF ₂ CF ₂ O) _m (CF ₂ O) _n -CF ₂ -(Q) _p -
(Wherein, Q is an alkylene or oxyalkylene group; p is 0 or 1; m/n is 0.2 to 5); It is a polyoxyalkylene group. ), and the like.

General formula above:
^CR2R3 = ^{CR4 -} Z ^{- CR5} = ^CR6R7
Examples of compounds represented by: CH ₂ =CH-(CF ₂ ) ₂ -CH=CH ₂ , CH ₂ =CH-(CF ₂ ) ₄ -CH=CH ₂ , CH ₂ =CH-(CF ₂ ) ₆ -CH=CH ₂ , the formula:
_CH2 =CH-Z1 ^- CH= _CH2
(In the formula, Z ¹ is a fluoropolyoxyalkylene group represented by —CH ₂ OCH ₂ —CF ₂ O—(CF ₂ CF ₂ O) _m1 (CF ₂ O) _n1 —CF ₂ —CH ₂ OCH ₂ — , m1/n1 is 0.5, and the molecular weight is 2000.).

Examples of monomers that provide crosslinking sites include CF2 ₌ CFOCF2CF _{( CF3} ) _OCF2CF2CN , CF2 _{= CFOCF2CF ( CF3} ) _OCF2CF2COOH , CF2 _{= CFOCF2CF (} CF ₃ ) OCF2CF2CH2I, _CF2 = _{CFOCF2CF2CH2I} , _{CH2 = CFCF2OCF ( CF3} ) _{CF2OCF ( CF3} )CN, _{CH2 = CFCF2OCF ( CF3} ) CF2OCF( _CF3 )COOH, _CH2 = _CFCF2OCF ( _CF3 ) _CF2OCF ( _CF3 ) _CH2OH , and _{CH2 = CHCF2CF2I} , _{CH2 =} CH ₍ CF2) ₂ One of preferred forms is at least one selected from the group consisting of CH= _CH2 .
As a monomer that provides the cross-linking site, CF ₂ ═CFOCF ₂ CF ₂ CH ₂ I improves the cross-linking density in cross-linking using peroxide and improves the compression set of the resulting molded product. It is particularly preferred because it can

Monomers that provide cross-linking sites also include, for example, the general formula:
CX ¹ ₂ =CX ¹ -Rf ¹ CHR ¹ X ²
(Wherein, X ¹ is a hydrogen atom, a fluorine atom or —CH ₃ , Rf ¹ is a fluoroalkylene group, a perfluoroalkylene group, a fluoropolyoxyalkylene group or a perfluoropolyoxyalkylene group, R ¹ is a hydrogen atom or —CH ₃ , X ² is an iodine atom or a bromine atom)
An iodine- or bromine-containing monomer (preferably an iodine-containing monomer) represented by the general formula:
CX ¹ ₂ = CX ¹ - Rf ¹ X ²
(Wherein, X ¹ is a hydrogen atom, a fluorine atom or —CH ₃ , Rf ¹ is a fluoroalkylene group, a perfluoroalkylene group, a fluoropolyoxyalkylene group or a perfluoropolyoxyalkylene group, X ² is an iodine atom or bromine atom)
An _iodine- or bromine _- containing monomer represented by the general _formula :
CF2 ₌ CFO( _CF2CF ( _CF3 )O) _m (CF2) _{n -} ^X5
(Wherein, m is an integer of 0 to 5, n is an integer of 1 to 3, X ⁵ is an iodine atom or a bromine atom (preferably an iodine atom))
and a monomer represented by the general formula:
_CH2 = _CFCF2O (CF( _CF3 ) _CF2O ) _m (CF( _CF3 )) _n - ^X5
(Wherein, m is an integer of 0 to 5, n is an integer of 1 to 3, X ⁵ is an iodine atom or a bromine atom (preferably an iodine atom))
At least one monomer selected from the group consisting of the monomers represented by is also one of preferred forms. Copolymer (III) can also be produced by using such an iodine- or bromine-containing monomer (preferably an iodine-containing monomer) as the other monomer.

In the copolymer (III), the monomer that provides the cross-linking site preferably accounts for 0.01 to 10 mol %, more preferably 0.01 to 2 mol %, of the total monomer units.

The fluorine-containing copolymer is copolymer (III) because it has excellent vulcanization properties, and the bending fatigue resistance, tear strength, amine resistance, fuel oil resistance, and low temperature resistance of the obtained molded article. is more preferred.

The above fluorine-containing copolymer is excellent in vulcanization properties, and in bending fatigue resistance, tear strength, amine resistance, fuel oil resistance, and low temperature resistance of the resulting molded product, Mooney viscosity at 121 ° C. (ML ₁₊₁₀ (121° C.)) is preferably 2 or more, more preferably 15 or more. In addition, it is preferably 200 or less, more preferably 150 or less, and even more preferably 100 or less from the viewpoint of good moldability. Mooney viscosity is a value measured according to ASTM-D1646 and JIS K6300-1:2013.

The fluorine-containing copolymer preferably has a number-average molecular weight (Mn) of 7,000 to 500,000 and a weight-average molecular weight (Mw) of 10,000 to 1,000,000 because the resulting molded article has excellent sealability. Preferably, Mw/Mn is 1.3 to 4.0.
The number average molecular weight (Mn), weight average molecular weight (Mw), and Mw/Mn are values measured by the GPC method.

The fluorine-containing copolymer can be produced by a general radical polymerization method. The form of polymerization may be bulk polymerization, solution polymerization, suspension polymerization or emulsion polymerization, but emulsion polymerization is preferred because it is industrially easy to implement.

In the above polymerization, a polymerization initiator, a chain transfer agent, a surfactant, and a solvent can be used, and conventionally known ones can be used.

In the polymerization of the fluorine-containing copolymer, an oil-soluble radical polymerization initiator or a water-soluble radical polymerization initiator can be used as a polymerization initiator.

Oil-soluble radical polymerization initiators may be known oil-soluble peroxides such as dialkylperoxycarbonates such as diisopropylperoxydicarbonate and disec-butylperoxydicarbonate; peroxy esters such as isobutyrate and t-butyl peroxypivalate; dialkyl peroxides such as di-t-butyl peroxide; (ω-hydro-tetradecafluoroheptanoyl) peroxide, di(ω-hydro-hexadecafluorononanoyl) peroxide, di(perfluorobutyryl) peroxide, di(perflupareryl) peroxide, di(perfluoro) hexanoyl) peroxide, di (perfluoroheptanoyl) peroxide, di (perfluorooctanoyl) peroxide, di (perfluorononanoyl) peroxide, di (ω-chloro-hexafluorobutyryl) peroxide, di(ω-chloro-decafluorohexanoyl) peroxide, di(ω-chloro-tetradecafluorooctanoyl) peroxide, ω-hydro-dodecafluoroheptanoyl-ω-hydrohexadecafluorononanoyl-peroxide, ω-chloro-hexafluorobutyryl-ω-chloro-decafluorohexanoyl-peroxide, ω-hydrododecafluoroheptanoyl-perfluorobutyryl-peroxide, di(dichloropentafluorobutanoyl) peroxide, di( trichlorooctafluorohexanoyl) peroxide, di(tetrachloroundecafluorooctanoyl) peroxide, di(pentachlorotetradecafluorodecanoyl) peroxide, di(undecachlorodotriacontafluorodocosanoyl) peroxide Typical examples include di[perfluoro(or fluorochloro)acyl]peroxides.

The water-soluble radical polymerization initiator may be a known water-soluble peroxide, for example, persulfuric acid, perboric acid, perchloric acid, perphosphoric acid, ammonium salts such as percarbonic acid, potassium salts, sodium salts , t-butyl permaleate, t-butyl hydroperoxide and the like. A reducing agent such as sulfites and sulfites may also be included, and the amount thereof used may be 0.1 to 20 times that of the peroxide.

The amount of the radical polymerization initiator to be added is not particularly limited, but an amount that does not significantly decrease the polymerization rate (for example, several ppm to water concentration) or more may be added at the beginning of the polymerization, sequentially, or continuously. and add. The upper limit is a range in which the heat of the polymerization reaction can be removed from the apparatus.

As surfactants, nonionic surfactants, anionic surfactants, cationic surfactants and the like can be used, and straight-chain surfactants having 4 to 20 carbon atoms such as ammonium perfluorooctanoate and ammonium perfluorohexanoate. Alternatively, a branched fluorine-containing anionic surfactant is preferred. The amount added (to polymerization water) is preferably 10 to 5000 ppm. More preferably, it is 50 to 5000 ppm.
A reactive emulsifier can also be used as a surfactant. _{The reactive emulsifier} is not particularly limited as long as it is a compound having one or _more unsaturated _bonds and one or _more hydrophilic groups. _{2 = CFCF2CF ( CF3} ) _{OCF2CF2COONH4} , CF2=CFOCF2CF _{( CF3} )OCF _{( CF3} ) _COONH4 . The amount added (to polymerization water) is preferably 10 to 5000 ppm. More preferably, it is 50 to 5000 ppm.

As the solvent, a solvent having no chain transfer property is preferable. In the case of solution polymerization, dichloropentafluoropropane (R-225) can be mentioned, and in the case of emulsion polymerization and suspension polymerization, water, a mixture of water and a water-soluble organic solvent, or a mixture of water and a water-insoluble organic solvent A mixture is given.

In the polymerization of the copolymers (I) and (II), examples of the chain transfer agent include esters such as dimethyl malonate, diethyl malonate, methyl acetate, ethyl acetate, butyl acetate and dimethyl succinate, Examples include isopentane, methane, ethane, propane, isopropanol, acetone, various mercaptans, carbon tetrachloride, and cyclohexane.

A bromine compound or an iodine compound (preferably an iodine compound) may be used as a chain transfer agent. The polymerization method using a bromine compound or an iodine compound includes, for example, a method of conducting emulsion polymerization in an aqueous medium under pressure in the presence of a bromine compound or an iodine compound in a substantially oxygen-free state. (iodine transfer polymerization method). Representative examples of the bromine compound or iodine compound to be used include, for example, the general formula:
R ² I _x Br _y
(Wherein, x and y are each an integer of 0 to 2 and satisfy 1 ≤ x + y ≤ 2, and R ² is a saturated or unsaturated fluorohydrocarbon group having 1 to 16 carbon atoms or chlorofluoro a hydrocarbon group, or a hydrocarbon group having 1 to 3 carbon atoms, which may contain an oxygen atom). By using a bromine compound or an iodine compound, iodine or bromine is introduced into the polymer and functions as a cross-linking point.

Examples of iodine compounds include 1,3-diiodoperfluoropropane, 2-iodoperfluoropropane, 1,3-diiodoperfluoropropane, 1,4-diiodoperfluorobutane, 1,5- Diiodo-2,4-dichloroperfluoropentane, 1,6-diiodoperfluorohexane, 1,8-diiodoperfluorooctane, 1,12-diiodoperfluorododecane, 1,16-diiodoperfluorohexadecane , diiodomethane, 1,2-diiodoethane, 1,3-diiodo _- n _- propane, _CF2Br2 , _BrCF2CF2Br , _CF3CFBrCF2Br , _{CFClBr2 , BrCF2CFClBr} , _CFBrClCFClBr , _{BrCF2CF2CF 2} Br, BrCF ₂ CFBrOCF ₃ , 1-bromo-2-iodoperfluoroethane, 1-bromo-3-iodoperfluoropropane, 1-bromo-4-iodoperfluorobutane, 2-bromo-3-iodoperfluoro butane, 3-bromo-4-iodoperfluorobutene-1, 2-bromo-4-iodoperfluorobutene-1, monoiodomonobromo and diiodomonobromo substitutions of benzene, and (2-iodoethyl) and (2-bromoethyl)-substituted compounds, etc., and these compounds may be used alone or in combination with each other.

Among these, 1,4-diiodoperfluorobutane, 1,6-diiodoperfluorohexane, and 2-iodoperfluoropropane are used from the viewpoint of polymerization reactivity, cross-linking reactivity, availability, etc. is preferred.

In the polymerization of the copolymer (III), it is preferable to use a bromine compound or an iodine compound (preferably an iodine compound) as a chain transfer agent. The polymerization method using a bromine compound or an iodine compound includes, for example, a method of conducting emulsion polymerization in an aqueous medium under pressure in the presence of a bromine compound or an iodine compound in a substantially oxygen-free state. (iodine transfer polymerization method). Representative examples of the bromine compound or iodine compound to be used include, for example, the general formula:
R ² I _x Br _y
(Wherein, x and y are each an integer of 0 to 2 and satisfy 1 ≤ x + y ≤ 2, and R ² is a saturated or unsaturated fluorohydrocarbon group having 1 to 16 carbon atoms or chlorofluoro a hydrocarbon group, or a hydrocarbon group having 1 to 3 carbon atoms, which may contain an oxygen atom). By using a bromine compound or an iodine compound, iodine or bromine is introduced into the polymer and functions as a cross-linking point.

Examples of iodine compounds include 1,3-diiodoperfluoropropane, 2-iodoperfluoropropane, 1,3-diiodoperfluoropropane, 1,4-diiodoperfluorobutane, 1,5- Diiodo-2,4-dichloroperfluoropentane, 1,6-diiodoperfluorohexane, 1,8-diiodoperfluorooctane, 1,12-diiodoperfluorododecane, 1,16-diiodoperfluorohexadecane , diiodomethane, 1,2-diiodoethane, 1,3-diiodo _- n _- propane, _CF2Br2 , _BrCF2CF2Br , _CF3CFBrCF2Br , _{CFClBr2 , BrCF2CFClBr} , _CFBrClCFClBr , _{BrCF2CF2CF 2} Br, BrCF ₂ CFBrOCF ₃ , 1-bromo-2-iodoperfluoroethane, 1-bromo-3-iodoperfluoropropane, 1-bromo-4-iodoperfluorobutane, 2-bromo-3-iodoperfluoro butane, 3-bromo-4-iodoperfluorobutene-1, 2-bromo-4-iodoperfluorobutene-1, monoiodomonobromo and diiodomonobromo substitutions of benzene, and (2-iodoethyl) and (2-bromoethyl)-substituted compounds, etc., and these compounds may be used alone or in combination with each other.
Among these, 1,4-diiodoperfluorobutane, 1,6-diiodoperfluorohexane, and 2-iodoperfluoropropane are used from the viewpoint of polymerization reactivity, cross-linking reactivity, availability, etc. is preferred.

In the polymerization of the copolymer (III), examples of the chain transfer agent include esters such as dimethyl malonate, diethyl malonate, methyl acetate, ethyl acetate, butyl acetate and dimethyl succinate, as well as isopentane, methane, Ethane, propane, isopropanol, acetone, various mercaptans, carbon tetrachloride, cyclohexane, and the like can also be used.

In the polymerization of the fluorine-containing copolymer, the polymerization temperature, polymerization pressure and polymerization time vary depending on the type of solvent and polymerization initiator, but are -15 to 150°C, atmospheric pressure to 6.5 MPa, and 1 to 24 hours. you can In particular, when an oil-soluble radical polymerization initiator containing a fluorine atom is used as the polymerization initiator in solution polymerization, the polymerization temperature is preferably -15 to 50°C, more preferably 10 to 35°C. When an oil-soluble radical polymerization initiator containing a fluorine atom is used in emulsion polymerization and suspension polymerization, the polymerization temperature is preferably 30 to 95°C. When a water-soluble radical polymerization initiator is used as the polymerization initiator, the polymerization temperature is preferably 0 to 100°C, more preferably 10 to 95°C.
The polymerization pressure is preferably 1.0 MPa or more because the resulting molded product has good bending fatigue resistance, tear strength, and compression set, and because the polymerization rate increases and productivity improves. , more preferably 2.0 MPa or more, still more preferably 3.0 MPa or more, and most preferably 4.5 MPa or more.

The fluorine-containing copolymer may be in any form such as an aqueous dispersion or powder.
In the case of emulsion polymerization, the powder of the fluorine-containing copolymer can be obtained by coagulating the dispersion after polymerization, washing with water, dehydrating and drying. The coagulation can be carried out by adding an inorganic salt such as aluminum sulfate or an inorganic acid, applying a mechanical shearing force, or freezing the dispersion. In the case of suspension polymerization, it can be obtained by recovering from the dispersion after polymerization and drying. In the case of solution polymerization, it can be obtained by drying the solution containing the fluorine-containing polymer as it is, or by adding a poor solvent dropwise for purification.

As the fluorine-containing copolymer, one type may be used, or two or more types may be used. In particular, a form in which two kinds of copolymers having different molecular structures are used together may be used.
Examples of the mode in which two types of copolymers having different molecular structures are used in combination include a mode in which two types of copolymers (I) with different molecular structures are used, a mode in which two types of copolymers (II) with different molecular structures are used, A form using two types of copolymers (III) having different molecular structures, a form using a combination of one type of copolymer (I) and one type of copolymer (II), and one type of copolymer (I) Examples include a mode in which one type of copolymer (III) is used in combination, and a mode in which one type of copolymer (II) and one type of copolymer (III) are used in combination.

As described above, when two types of copolymers are used together as the fluorocopolymer, one type is a branched fluoropolymer and the other type is a linear fluoropolymer. is preferred. More preferably, one type described in WO 2009/119409 pamphlet (A) has a peroxide crosslinkable crosslinkable site and has a number average molecular weight in the range of 1,000 to 300,000. , and a branched fluorine-containing polymer having a Mark-Hawin slope a of less than 0.6 when the absolute weight molecular weight and the intrinsic viscosity are plotted on a Mark-Hawin plot in which the horizontal axis is the absolute weight molecular weight and the vertical axis is the intrinsic viscosity Another type is (B) a mark in which the number average molecular weight is in the range of 1,000 to 250,000, and the absolute weight molecular weight and the intrinsic viscosity are indicated by the absolute weight molecular weight on the horizontal axis and the intrinsic viscosity on the vertical axis. - a form that is a linear fluoropolymer having a Mark-Hawin slope a of 0.6 or more when plotted on a Howwin plot, or an ethylenically unsaturated polymer in which one type comprises (A) at least one fluoroolefin Saturated compounds and the general formula:
^CY12 ₌ ^{CY2Rf2X2 _ _}
(wherein Y ¹ and Y ² are a fluorine atom, a hydrogen atom or —CH ₃ ; Rf ² may have an etheric oxygen atom, and some or all of the hydrogen atoms are directly A chain or branched fluorine ^- containing alkylene group; X2 is an iodine atom or a bromine atom (preferably an iodine atom). A branched fluorine-containing polymer obtained by a production method characterized in that the addition of 0 to 10% by mass of the total amount of ethylenically unsaturated compounds added to the polymerization system after the addition of the initiator is started. and the other type is (B) a mark-ha having a number average molecular weight in the range of 1,000 to 250,000 and having an absolute weight molecular weight and an intrinsic viscosity on the horizontal axis and the intrinsic viscosity on the vertical axis. It is a linear fluoropolymer having a Mark-Hawin slope a of 0.6 or more when plotted on a Win plot.
Thus, when two or more types of polymers are used as the fluorine-containing copolymer in the present invention, one type is the copolymer (II) or the copolymer (III), and the peroxide-crosslinkable crosslinking site and having a number average molecular weight in the range of 1,000 to 300,000, and the absolute weight molecular weight and intrinsic viscosity were plotted on a Mark-Hawin plot with the absolute weight molecular weight on the horizontal axis and the intrinsic viscosity on the vertical axis. A branched fluoropolymer having a Mark-Hawin slope a of less than 0.6, or an ethylenically unsaturated compound containing at least one fluoroolefin, and the general formula:
^CY12 ₌ ^{CY2Rf2X2 _ _}
(wherein Y ¹ and Y ² are a fluorine atom, a hydrogen atom or —CH ₃ ; Rf ² may have an etheric oxygen atom, and some or all of the hydrogen atoms are directly A chain or branched fluorine ^- containing alkylene group; X2 is an iodine atom or a bromine atom (preferably an iodine atom). A branched fluorine-containing polymer obtained by a production method characterized in that the addition of 0 to 10% by mass of the total amount of the ethylenically unsaturated compound added to the polymerization system after the addition of the initiator is started. , Another type is copolymer (I), copolymer (II) or copolymer (III), having a number average molecular weight in the range of 1,000 to 250,000, and having an absolute weight molecular weight and There is also a form of a linear fluoropolymer having a Mark-Hawin slope a of 0.6 or more when the intrinsic viscosity is plotted on a Mark-Hawin plot in which the horizontal axis is the absolute weight molecular weight and the vertical axis is the intrinsic viscosity. This is the preferred form.

The composition contains a cross-linking agent, and may further contain a cross-linking aid and a cross-linking accelerator in addition to the cross-linking agent. Cross-linking agents, cross-linking auxiliaries, and cross-linking accelerators are the cross-linking system, type of fluororubber to be cross-linked (for example, copolymer composition, presence or absence and type of cross-linkable group, etc.), specific application and usage form of the resulting molded product, etc. It can be appropriately selected according to kneading conditions and the like.

As the cross-linking system, for example, a peroxide cross-linking system, a polyol cross-linking system, a polyamine cross-linking system, or the like can be used.

(Peroxide cross-linking system)
In the case of cross-linking with a peroxide cross-linking system, the cross-linking point has a carbon-carbon bond. In comparison, the resulting molded article is characterized by excellent chemical resistance and steam resistance.

As the cross-linking agent, a peroxide cross-linking type cross-linking agent is preferable. The cross-linking agent for the peroxide cross-linking system may be a peroxide that can easily generate peroxy radicals in the presence of heat or a redox system. Specifically, for example, 1,1-bis(t -butylperoxy)-3,5,5-trimethylcyclohexane, 2,5-dimethylhexane-2,5-dihydroperoxide, di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide, α,α-bis(t-butylperoxy)-p-diisopropylbenzene, α,α-bis(t-butylperoxy)-m-diisopropylbenzene, α,α-bis(t-butylperoxy)-m -diisopropylbenzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di(t-butylperoxy)-hexyne-3, benzoyl peroxide , t-butylperoxybenzene, t-butylperoxybenzoate, t-butylperoxymaleic acid, and t-butylperoxyisopropyl carbonate. Among these, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane and 2,5-dimethyl-2,5-di(t-butylperoxy)-hexyne-3 are preferred. In addition, when the above peroxide is blended into the above composition, it may be impregnated with an inert inorganic powder or the like.

In the peroxide cross-linking system, it is usually preferable to include a polyfunctional co-crosslinking agent as a cross-linking aid. Peroxide-based cross-linking agents, particularly polyfunctional co-cross-linking agents for organic peroxide-based cross-linking agents, include triallyl cyanurate, trimethallyl isocyanurate, triallyl isocyanurate (TAIC), triacrylformal, and triallyl. trimellitate, N,N'-m-phenylenebismaleimide, dipropargyl terephthalate, diallyl phthalate, tetraallyl terephthalate amide, triallyl phosphate, bismaleimide, fluorinated triallyl isocyanurate (1,3,5-tris(2 ,3,3-trifluoro-2-propenyl)-1,3,5-triazine-2,4,6-trione), tris(diallylamine)-S-triazine, triallyl phosphite, N,N-diallylacrylamide , 1,6-divinyldodecafluorohexane, hexaallylphosphoramide, N,N,N',N'-tetraallylphthalamide, N,N,N',N'-tetraallylmalonamide, trivinyl isocyanurate , 2,4,6-trivinylmethyltrisiloxane, tri(5-norbornene-2-methylene)cyanurate, triallyl phosphite and the like. Among these, triallyl isocyanurate (TAIC) or trimethallyl isocyanurate is preferable from the viewpoint of crosslinkability and physical properties of the crosslinked product. Further, when the above-mentioned cross-linking aid is blended into the above-mentioned composition, it may be impregnated with an inert inorganic powder or the like.

The amount of the peroxide crosslinking agent is preferably 0.1 to 10 parts by mass, more preferably 0.3 to 7 parts by mass, and particularly preferably 100 parts by mass of the fluorine-containing copolymer. 0.4 to 5 parts by mass, more preferably 0.5 to 3 parts by mass. If the peroxide cross-linking agent is less than 0.1 parts by mass, the cross-linking of the fluorine-containing copolymer tends not to proceed sufficiently. Molding defects such as foaming tend to occur more easily during molding.

The amount of the cross-linking aid compounded is usually 0.1 to 10 parts by mass, preferably 0.3 to 7 parts by mass, and more preferably 0 parts by mass with respect to 100 parts by mass of the fluorine-containing copolymer. .4 to 5 parts by mass. If the amount of the cross-linking aid is less than 0.1 part by mass, the strength of the resulting molded article tends to be too small to withstand practical use. tends to be smaller.

(Polyol cross-linking system)
Crosslinking with a polyol crosslink system is preferable because it has a carbon-oxygen bond at the crosslink point, has a small compression set, and is excellent in moldability.

As the polyol cross-linking agent, a compound conventionally known as a cross-linking agent for fluororubber can be used. It is preferably used.

The polyhydroxyaromatic compound is not particularly limited, and examples thereof include 2,2-bis(4-hydroxyphenyl)propane (hereinafter referred to as bisphenol A), 2,2-bis(4-hydroxyphenyl)perfluoropropane. (hereinafter referred to as bisphenol AF), resorcin, 1,3-dihydroxybenzene, 1,7-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 4,4'-dihydroxydiphenyl, 4,4' -dihydroxystilbene, 2,6-dihydroxyanthracene, hydroquinone, catechol, 2,2-bis(4-hydroxyphenyl)butane (hereinafter referred to as bisphenol B), 4,4-bis(4-hydroxyphenyl)valeric acid, 2 , 2-bis(4-hydroxyphenyl)tetrafluorodichloropropane, 4,4'-dihydroxydiphenylsulfone, 4,4'-dihydroxydiphenylketone, tri(4-hydroxyphenyl)methane, 3,3',5,5 '-Tetrachlorobisphenol A, 3,3',5,5'-tetrabromobisphenol A and the like. These polyhydroxyaromatic compounds may be alkali metal salts, alkaline earth metal salts, etc. However, when the copolymer is coagulated using an acid, it is preferable not to use the above metal salts.

Among these, polyhydroxy compounds are preferable because the compression set of the obtained molded article is small and the moldability is excellent, and polyhydroxy aromatic compounds are more preferable because the heat resistance of the obtained molded article is excellent. Bisphenol AF is preferred, and bisphenol AF is more preferred.

In addition, the polyol cross-linking system usually preferably contains a cross-linking accelerator. The use of a cross-linking accelerator can accelerate the cross-linking reaction by promoting the formation of intramolecular double bonds in the dehydrofluoric acid reaction of the fluororubber main chain and the addition of a polyhydroxy compound to the generated double bonds. can.

An onium compound is generally used as a cross-linking accelerator for a polyol cross-linking system. The onium compound is not particularly limited and includes, for example, ammonium compounds such as quaternary ammonium salts, phosphonium compounds such as quaternary phosphonium salts, oxonium compounds, sulfonium compounds, cyclic amines, monofunctional amine compounds, and the like. Among these, quaternary ammonium salts and quaternary phosphonium salts are preferred.

The quaternary ammonium salt is not particularly limited. 4,0]-7-undecenium iodide, 8-methyl-1,8-diazabicyclo[5,4,0]-7-undecenium hydroxide, 8-methyl-1,8-diazabicyclo[5 ,4,0]-7-undecenium methyl sulfate, 8-ethyl-1,8-diazabicyclo[5,4,0]-7-undecenium bromide, 8-propyl-1,8-diazabicyclo[5 ,4,0]-7-undecenium bromide, 8-dodecyl-1,8-diazabicyclo[5,4,0]-7-undecenium chloride, 8-dodecyl-1,8-diazabicyclo[5,4 ,0]-7-undecenium hydroxide, 8-eicosyl-1,8-diazabicyclo[5,4,0]-7-undecenium chloride, 8-tetracosyl-1,8-diazabicyclo[5,4 ,0]-7-undecenium chloride, 8-benzyl-1,8-diazabicyclo[5,4,0]-7-undecenium chloride (hereinafter referred to as DBU-B), 8-benzyl-1, 8-diazabicyclo[5,4,0]-7-undecenium hydroxide, 8-phenethyl-1,8-diazabicyclo[5,4,0]-7-undecenium chloride, 8-(3-phenylpropoxy l)-1,8-diazabicyclo[5,4,0]-7-undecenium chloride and the like. Among these, DBU-B is preferable in terms of crosslinkability and physical properties of the crosslinked product.

Further, the quaternary phosphonium salt is not particularly limited, and examples thereof include tetrabutylphosphonium chloride, benzyltriphenylphosphonium chloride (hereinafter referred to as BTPPC), benzyltrimethylphosphonium chloride, benzyltributylphosphonium chloride, tributylallylphosphonium chloride, tributyl -2-Methoxypropylphosphonium chloride, benzylphenyl(dimethylamino)phosphonium chloride, and the like. Among these, benzyltriphenylphosphonium chloride (BTPPC) is preferred from the viewpoint of crosslinkability and physical properties of the crosslinked product.

As the cross-linking accelerator, a solid solution of a quaternary ammonium salt or a quaternary phosphonium salt and bisphenol AF, or a chlorine-free cross-linking accelerator disclosed in JP-A-11-147891 can also be used.

The blending amount of the polyol cross-linking agent is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 7 parts by mass, based on 100 parts by mass of the fluorine-containing copolymer. If the polyol cross-linking agent is less than 0.01 parts by mass, the cross-linking of the fluorine-containing copolymer tends not to proceed sufficiently. tend to be smaller.

The amount of the cross-linking accelerator to be blended is preferably 0.01 to 8 parts by mass, more preferably 0.02 to 5 parts by mass, per 100 parts by mass of the fluorine-containing copolymer. If the amount of the cross-linking accelerator is less than 0.01 parts by mass, the cross-linking of the fluorocopolymer tends not to proceed sufficiently. It tends to get worse.

(Polyamine cross-linking system)
When cross-linked by a polyamine cross-linking system, it has a carbon-nitrogen double bond at the cross-linking point, and is characterized by excellent dynamic mechanical properties of the resulting molded product. However, compared with the case of cross-linking using a polyol cross-linking type or peroxide cross-linking type cross-linking agent, the resulting molded article tends to have a larger compression set.

Examples of polyamine cross-linking agents include polyamine compounds such as hexamethylenediamine carbamate, N,N'-dicinnamylidene-1,6-hexamethylenediamine, and 4,4'-bis(aminocyclohexyl)methane carbamate. Among these, N,N'-dicinnamylidene-1,6-hexamethylenediamine is preferred.

The amount of the polyamine-based cross-linking agent to be blended is preferably 0.01 to 10 parts by mass, more preferably 0.2 to 7 parts by mass, per 100 parts by mass of the fluorine-containing copolymer. If the polyamine-based cross-linking agent is less than 0.01 parts by mass, the cross-linking of the fluorocopolymer tends not to proceed sufficiently. tends to be smaller.

The composition preferably contains carbon black.
Examples of carbon black include, but are not limited to, thermal black, lamp black, etc. Specific examples include N990 (N ₂ SA: 8 m ² /g, DBP: 43 ml/100 g). These carbon blacks may be used alone or in combination of two or more.

The amount of carbon black compounded is preferably 0 to 100 parts by mass with respect to 100 parts by mass of the fluorine-containing copolymer. If the amount of carbon black is too high, the resulting molded article tends to be too hard, and if the amount is too low, the resulting molded article tends to have poor mechanical properties. A more preferable blending amount is 5 parts by mass or more, more preferably 10 parts by mass or more based on 100 parts by mass of the fluorine-containing copolymer, from the viewpoint of good physical property balance of the resulting molded body. 49 parts by mass or less is preferable, and 30 parts by mass or less is more preferable, from the viewpoint of good balance of physical properties.

The composition used in the present invention may optionally contain conventional rubber compounds such as fillers, processing aids, plasticizers, colorants, tackifiers, adhesion aids, acid acceptors, pigments and flame retardants. , lubricants, light stabilizers, weather stabilizers, antistatic agents, UV absorbers, antioxidants, release agents, foaming agents, fragrances, oils, softeners, polyethylene, polypropylene, polyamide, polyester, polyurethane, etc. Polymers other than those described above may be blended within a range that does not impair the effects of the present invention.

Fillers include metal oxides such as calcium oxide, magnesium oxide, titanium oxide and aluminum oxide; metal hydroxides such as magnesium hydroxide, aluminum hydroxide and calcium hydroxide; magnesium carbonate, aluminum carbonate, calcium carbonate and carbonate. Carbonates such as barium; silicates such as magnesium silicate, calcium silicate, sodium silicate, aluminum silicate; sulfates such as aluminum sulfate, calcium sulfate, barium sulfate; synthetic hydrotalcite, molybdenum disulfide, sulfide Iron, metal sulfides such as copper sulfide; Examples include carbon fiber, aramid fiber, various whiskers, glass fiber, organic reinforcing agents, organic fillers, polytetrafluoroethylene, mica, silica, celite, and clay. Examples of acid acceptors include calcium oxide, magnesium oxide, lead oxide, zinc oxide, magnesium hydroxide, calcium hydroxide, aluminum hydroxide, and hydrotalcite. may These may be added at any step in the kneading method described above, but are preferably added when the fluororubber and carbon black are kneaded with an internal kneader or roll kneader.

Processing aids include higher fatty acids such as stearic acid, oleic acid, palmitic acid, and lauric acid; higher fatty acid salts such as sodium stearate and zinc stearate; higher fatty acid amides such as stearic acid amide and oleic acid amide; higher fatty acid esters such as ethyl; waxes derived from animals and plants such as carnauba wax; waxes derived from minerals such as ceresin wax; petroleum waxes such as paraffin wax; polyglycols such as ethylene glycol, glycerin and diethylene glycol; Group hydrocarbons; silicone oils, silicone polymers, low-molecular-weight polyethylene, phthalates, phosphates, rosin, (halogenated) dialkylamines, surfactants, sulfone compounds, fluorine-based auxiliary agents, organic amine compounds etc. can be exemplified.

Preferred organic amine compounds include primary amines represented by R ¹ NH ₂ , secondary amines represented by R ¹ R ² NH, and tertiary amines represented by R ¹ R ² R ³ N. R ¹ , R ² , and R ³ are the same or different, and each is preferably an alkyl group having 1 to 50 carbon atoms. May contain a bond. The alkyl group may be linear or branched.

Examples of primary amines include coconutamine, octylamine, laurylamine, stearylamine, oleylamine, beef tallowamine, 17-phenyl-heptadecylamine, octadeca-7,11-dienylamine, octadeca-7,9-dienylamine, octadec- 9-enylamine, 7-methyl-octadech-7-enylamine and the like, secondary amines such as distearylamine, and tertiary amines such as dimethyloctylamine, dimethyldecylamine, dimethyllaurylamine, dimethylmyristylamine, dimethylpalmitylamine, dimethylstearylamine, dimethylbehenylamine and the like. Among them, amines having about 20 carbon atoms, particularly primary amines, are preferable from the viewpoint of easy availability and good workability.

The blending amount of the organic amine compound is preferably 0 to 5 parts by mass with respect to 100 parts by mass of the fluorine-containing copolymer. If the amount of the organic amine compound is too large, kneading tends to become difficult. A more preferable blending amount is 2 parts by mass or less from the viewpoint of ease of kneading with respect to 100 parts by mass of the fluorine-containing copolymer.

As the acid-accepting agent, for example, metal hydroxides such as calcium hydroxide; metal oxides such as magnesium oxide and zinc oxide; hydrotalcite;

The amount of the acid acceptor compounded is preferably 0 to 50 parts by mass with respect to 100 parts by mass of the fluorine-containing copolymer. If the amount of the acid acceptor is too large, the elongation of the molded article obtained tends to be small and the acid resistance tends to be poor. A more preferable blending amount is 10 parts by mass or less, more preferably 5 parts by mass or less, from the viewpoint of the physical properties of the molded article to be obtained and the ease of kneading.

Examples of tackifiers include coumarone resins, coumarone-indene resins, coumarone-indene-styrene resins, naphthenic oils, phenolic resins, rosin, rosin esters, hydrogenated rosin derivatives, terpene resins, modified terpene resins, terpene-phenolic Resin, hydrogenated terpene resin, α-pinene resin, alkylphenol/acetylene resin, alkylphenol/formaldehyde resin, styrene resin, C5 petroleum resin, C9 petroleum resin, alicyclic petroleum resin, C5/C9 copolymer Examples include petroleum resins, xylene-formaldehyde resins, polyfunctional methacrylates, polyfunctional acrylates, metal oxides (such as magnesium oxide), and metal hydroxides. 0 to 20 parts by mass is preferred. These tackifiers may be used alone or in combination of two or more.

The above composition in the present invention is preferably obtained by kneading at least the fluorine-containing copolymer, the cross-linking agent, and optionally the above-described cross-linking aid.

An open roll, a Banbury mixer, a pressure kneader, an extruder, or the like can be used for the kneading.

The complex-shaped molded article of the present invention has a crosslinked fluororubber layer obtained by crosslinking the composition used in the present invention.

The complex-shaped molded article of the present invention may be composed of a single layer of a crosslinked fluororubber layer, or may have a multi-layered structure in which layers made of other materials are laminated.

As the method for producing a molded article having a complicated shape according to the present invention, a conventional method for producing a molded article having a complicated shape can be employed except that the above composition is used as the rubber composition. For example, it can be produced by cross-linking molding (primary cross-linking) the above composition using a mold corresponding to a complicated shape and removing it from the mold. Alternatively, the above composition can be preformed by extrusion or the like, and then pressurized and heated with steam or the like to be crosslinked.

The primary cross-linking method for obtaining a complex-shaped molded article may be selected as appropriate. For example, it can be obtained by cross-linking and molding using a general rubber molding machine equipped with a complex-shaped mold. A compression press, an injection molding machine, an injection molding machine, or the like can be used as a molding machine for rubber, and cross-linking is performed by heating. In addition, if secondary cross-linking is required depending on the purpose of use of the cross-linked product, further oven cross-linking may be performed. Generally, primary crosslinking can be carried out at 0.2-15 MPa and 130-230° C. for 3-180 minutes, and secondary crosslinking can be carried out at 150-300° C. for 10 minutes-48 hours.

For example, as a method of manufacturing a compact having a bellows structure,
(I) preparing a composition containing a cross-linking agent and the fluorine-containing copolymer kneaded with a cross-linking agent, optionally a cross-linking aid, and a cross-linking accelerator;
(II) Putting the above composition into a compression press molding machine equipped with a mold that provides a bellows structure,
(III) cross-linking at 130° C. to 230° C. to obtain a cross-linked molding containing a cross-linked fluororubber layer;
(IV) A method of removing the obtained crosslinked molded product from the mold at a temperature of 130°C to 230°C can be exemplified.

The cross-linked fluororubber layer (after cross-linking) in the complex-shaped molded article preferably has an elongation at break of 300% or more at 23°C. The elongation at break is more preferably 400% or more, still more preferably 500% or more, and particularly preferably 540% or more.

The cross-linked fluororubber layer (after cross-linking) in the complex-shaped molded article preferably has a tensile strength of 10 MPa or more, further 15 MPa or more, particularly 20 MPa or more at 23°C.
The tensile strength and elongation at break are measured using a No. 6 dumbbell according to JIS-K6251:2010.

The cross-linked fluororubber layer (after cross-linking) in the complex-shaped molded article has a non-cut angle-type tear strength of 40 kN/m or more, further 50 kN/m or more, particularly 55 kN/m or more at 23°C. This is preferable because the complex-shaped molded product has excellent resistance to bending fatigue.
The tear strength of the non-cutting angle type is measured according to JIS K6252-1:2015.

The cross-linked fluororubber layer (after cross-linking) in the complex-shaped molded product has a trouser-type tear of 5.0 to 25.0 kN/m, further 7.0 kN/m or more, particularly 8.5 kN/m or more at 23 ° C. It is preferable to have strength because the bending fatigue resistance of the molded article having a complicated shape is excellent.
The trouser type tear strength is measured according to JIS K6252-1:2015.

In the case of producing a multi-layered complex-shaped molded product, the above composition may be laminated with a layer made of another material before cross-linking, or the above composition may be cross-linked to form a cross-linked fluororubber layer. After that, it may be laminated with a layer made of another material.

In addition, in the multi-layered complex-shaped molded body, layers made of other materials include layers made of other rubbers, layers made of thermoplastic resin, various fiber reinforcement layers, canvas, metal plate layers, metal foil layers, and the like. mentioned.

As other rubbers, when chemical resistance and flexibility are particularly required, acrylonitrile-butadiene rubber or hydrogenated rubber thereof, blend rubber of acrylonitrile-butadiene rubber and polyvinyl chloride, fluororubber, epichlorohydrin rubber , EPDM and acrylic rubber, preferably acrylonitrile-butadiene rubber or its hydrogenated rubber, blend rubber of acrylonitrile-butadiene rubber and polyvinyl chloride, fluororubber, epichlorohydrin rubber. It is more preferable to consist of at least one rubber selected from the group consisting of.

Further, as the thermoplastic resin, at least one selected from the group consisting of fluororesin, polyamide resin, polyolefin resin, polyester resin, polyvinyl alcohol resin, polyvinyl chloride resin, and polyphenylene sulfide resin. Plastic resins are preferred, and thermoplastic resins made of at least one selected from the group consisting of fluorine resins, polyamide resins, polyvinyl alcohol resins, and polyphenylene sulfide resins are more preferred.

Moreover, when producing a complex-shaped molded article having a multi-layer structure, surface treatment may be performed as necessary. The type of surface treatment is not particularly limited as long as it is a treatment method that enables adhesion. For example, discharge treatment such as plasma discharge treatment and corona discharge treatment, wet method metallic sodium / naphthalene solution treatment. etc. Primer treatment is also suitable as the surface treatment. Primer treatment can be performed according to a conventional method. When applying primer treatment, it is possible to treat the surface of fluororesin that has not been surface-treated, but plasma discharge treatment, corona discharge treatment, metal sodium / naphthalene solution treatment, etc. are applied in advance, and then primer treatment is performed. , is more effective.

The complex-shaped molded article of the present invention is used, for example, in the field of various industrial vehicles such as automobiles, construction machinery vehicles, agricultural machinery vehicles, and railway vehicles; machine tools, construction machinery, agricultural machinery, mining machinery, industrial robots, chemical plants, and coating machines. , chemical transfer machines, food processing machines, hydraulic tools, and other industrial and mining machinery fields; ship and aircraft fields.

Examples of the complex-shaped molded article of the present invention include bellows-structured molded articles, and specific examples thereof include joint members such as flexible joints and expansion joints, boots, grommets, and the like.

A joint member is a joint used in piping and piping equipment.It prevents vibration and noise generated from the piping system, absorbs expansion and contraction and displacement due to temperature and pressure changes, absorbs dimensional fluctuations, earthquakes, and ground subsidence. It is used for purposes such as mitigation and prevention of the impact of

Flexible joints and expansion joints are preferably used as complex-shaped moldings for, for example, shipbuilding piping, mechanical piping such as pumps and compressors, chemical plant piping, electrical piping, civil engineering/water supply piping, and automobiles. can.

Boots include, for example, constant velocity joint boots, dust covers, rack and pinion steering boots, pin boots, piston boots, etc., boots for automobiles, boots for agricultural machinery, boots for industrial vehicles, boots for construction machinery, boots for hydraulic machinery, It can be preferably used as complex-shaped moldings such as various industrial boots such as compression machine boots, centralized lubricator boots, liquid transfer boots, firefighting boots, and various liquefied gas transfer boots.
The complex-shaped molded article of the present invention can also be suitably used for a primer bulb shown below. Examples include primer bulbs for automobiles, ships, aircraft, construction machinery, agricultural machinery, and mining machinery. For example, it is particularly useful as a marine primer bulb.

The complex-shaped molded article of the present invention can also be suitably used for diaphragms shown below.
For example, automobile engine applications include diaphragms for fuel systems, exhaust systems, brake systems, drive systems, ignition systems, etc., which require heat resistance, oxidation resistance, fuel resistance, and low gas permeability.
Examples of diaphragms used in the fuel system of automobile engines include fuel pump diaphragms, carburetor diaphragms, pressure regulator diaphragms, pulsation damper diaphragms, ORVR diaphragms, canister diaphragms, and auto fuel cock diaphragms. .
Diaphragms used in exhaust systems of automobile engines include, for example, wastegate diaphragms, actuator diaphragms, and EGR diaphragms.
Diaphragms used in brake systems of automobile engines include, for example, diaphragms for air brakes.
Diaphragms used in drive systems of automobile engines include, for example, oil pressure diaphragms.
Diaphragms used in ignition systems of automobile engines include, for example, diaphragms for distributors.

Applications other than automobile engines include general pump diaphragms, valve diaphragms, filter press diaphragms, blower diaphragms, and air conditioners that require heat resistance, oil resistance, chemical resistance, steam resistance, and low gas permeability. diaphragms for equipment, diaphragms for control equipment, diaphragms for water supply, diaphragms used in pumps for supplying hot water, diaphragms for high-temperature steam, diaphragms for semiconductor equipment (e.g. chemical transfer used in manufacturing processes diaphragms for food processing equipment, diaphragms for liquid storage tanks, diaphragms for pressure switches, diaphragms used in oil exploration and oil drilling applications (e.g. diaphragms for lubricating oil supply in oil drilling pits, etc.), gas instantaneous water heaters and Diaphragms for gas appliances such as gas meters, diaphragms for accumulators, diaphragms for air springs such as suspensions, diaphragms for ship screw feeders, diaphragms for medical artificial hearts, and the like.

EXAMPLES Next, the present invention will be described with reference to examples, but the present invention is not limited only to these examples.

Each numerical value in the examples was measured by the following method.

<Fluorine-containing copolymer composition>
Measured by NMR method.
Measuring device: VNMRS400 manufactured by Varian
Resonance frequency: 376.04 (Sfrq)
Pulse wave: 30° (pw = 6.8)

<Glass transition temperature (Tg)>
Using a differential scanning calorimeter (manufactured by Hitachi Techno Science, X-DSC823e), after cooling to -75 ° C., 10 mg of the sample was heated at 20 ° C./min to obtain a DSC curve. The glass transition temperature was defined as the temperature at which the extended line of the baseline before and after the transition intersects with the tangent line at the point of inflection of the DSC curve.

<Measurement of iodine content>
12 mg of sample was mixed with 5 mg of Na ₂ SO ₃ , and 30 mg of Na ₂ CO ₃ and K ₂ CO ₃ were mixed in 20 ml of pure water at a ratio of 1:1 (mass ratio). After burning in medium and oxygen for 30 minutes, measurement can be performed using a Shimadzu 20A ion chromatograph. A calibration curve was measured using KI standard solutions, one containing 0.5 ppm and one containing 1.0 ppm iodide ion.

<Mooney viscosity>
Mooney viscosity was measured according to JIS K6300-1:2013 (measurement temperature: 121° C. or 100° C., L-type rotor).

<Vulcanization characteristics>
Using the fluororubber compositions obtained in Examples and Comparative Examples, the optimum vulcanization time (T90) was measured with a RUBBER PROCESSANALY ANALYZER RPA2000 (manufactured by ALPHA TECHNOLOGIES) according to JIS K6300-2:2001 ( temperature 160°C).

<Tensile strength and elongation at break>
Using the crosslinked sheets with a thickness of 2 mm obtained in Examples and Comparative Examples, Tensilon RTG-1310 manufactured by A&D, in accordance with JIS K6251: 2010, a test speed of 500 mm / min, dumbbell No. 6 shape, Tensile strength (Tb) and elongation at break (Eb) were measured at a test temperature of 23°C.

<Tear strength (angle type without notch)>
Using the crosslinked sheets with a thickness of 2 mm obtained in Examples and Comparative Examples, Tensilon RTG-1310 manufactured by A&D in accordance with JIS K6252-1: 2015, a test speed of 500 mm / min, a test temperature of 23. °C, the tear strength of the non-cutting angle shape was measured.

<Tear strength (Trouser type)>
Using the 2 mm thick crosslinked sheets obtained in Examples and Comparative Examples, Tensilon RTG-1310 manufactured by A&D in accordance with JIS K6252-1: 2015, test speed 100 mm / min, test temperature 23 ℃, the tear strength of the trouser type was measured.

<Hardness>
Three 2-mm-thick crosslinked sheets obtained in Examples and Comparative Examples were stacked, and hardness was measured with a type A durometer according to K6253-3:2012 (peak value and after 3 seconds).

<Bending fatigue resistance (Dematcher bending crack initiation test)>
Using the fluororubber compositions obtained in Examples and Comparative Examples, dematcher test pieces were crosslinked under the molding conditions shown in Table 1. A dematcher flex crack initiation test was performed according to JIS K6260:2017. The state of cracks was visually confirmed every 20,000 times. The measurement was performed 3 times, and the median value was adopted as the test result.

<Amine resistance test>
An immersion test was performed at 125° C. for 168 hours using diethanolamine/water=50/50% by weight. The volume swelling rate (ΔV) after the immersion test was measured, and the rate of change with respect to the value before immersion was obtained. ΔV is the volume change rate (representing the degree of swelling) after the sample piece is immersed under predetermined conditions. It is represented by (V−Vo)/Vo×100. Volume is calculated from the weight in air and the weight in water.

<Method for Evaluating Releasability of Rubber Molding with Complex Shape>
Using a mold (L1 = 10 mm Φ, L2 = 12 mm, L3 = 8 mm, L4 = 2 mm, molded body thickness 2 mm) consisting of mold A and mold B as shown in Fig. 1, Examples and Comparative Examples 30 g of the fluororubber composition obtained in 1. above is charged and subjected to compression molding at 160° C. for 10 minutes. After molding, the molding 1 is demolded from the mold A with air of 1.5 MPaG. At this time, the product that cracks or tears is treated as a defective product. Molding is performed 5 times, and the defect rate of the molded body is obtained.

Each material described in Table 1 used in Examples and Comparative Examples is shown below.
(Fluorine-containing copolymer)
Fluorine-containing copolymer 1: vinylidene fluoride prepared by iodine transfer polymerization/2,3,3,3-tetrafluoropropene = 77/23 (molar ratio) peroxide vulcanizable polymer (Mooney viscosity at 121°C ML ₁₊₁₀ : 25, glass transition temperature: -13°C, iodine content: 0.21% by mass)
Fluorine-containing copolymer 2: Vinylidene fluoride prepared by iodine transfer polymerization/2,3,3,3-tetrafluoropropene = 77/23 (molar ratio) peroxide vulcanizable polymer (Mooney viscosity at 121°C ML ₁₊₁₀ : 60, glass transition temperature: -13°C, iodine content: 0.14% by mass)
Fluorine-containing copolymer 3: Peroxide vulcanizable polymer of vinylidene fluoride/hexafluoropropylene = 78/22 (molar ratio) prepared by iodine transfer polymerization (Mooney viscosity at 100°C ML ₁₊₁₀ : 70, glass transition temperature : -20°C, iodine content: 0.18% by mass)
Fluorine-containing copolymer 4: Peroxide vulcanizable polymer of vinylidene fluoride/hexafluoropropylene/tetrafluoroethylene = 50/30/20 (molar ratio) prepared by iodine transfer polymerization (Mooney viscosity at 100°C ML ₁₊₁₀ : 50, glass transition temperature is -6 ° C., iodine content: 0.23% by mass)

(Carbon black)
Carbon black: N990 ( _N2SA = ^8m2 /g, DBP oil absorption=43ml/100g).

(crosslinking agent)
2,5-dimethyl-2,5-di(t-butylperoxy)hexane

(crosslinking aid)
triallyl isocyanurate

Example 1
Each component shown in Table 1 was blended in the compounding amount shown in Table 1, and kneaded at 30 to 50°C in a conventional manner using an 8-inch open roll to prepare a fluororubber composition. Using the obtained fluororubber composition, vulcanization properties were measured.

Further, the obtained fluororubber composition was subjected to cross-linking molding under the molding conditions shown in Table 1 to obtain a cross-linked sheet having a thickness of 2 mm.
Using the obtained crosslinked sheet, tensile strength, elongation at break, tear strength and hardness were measured. Table 1 shows the results.

Furthermore, using the obtained fluororubber composition, a dematcher test piece was crosslinked and molded under the molding conditions shown in Table 1, and a dematcher flex crack initiation test was performed. Table 1 shows the results.
Furthermore, using the obtained fluororubber composition, the defect rate was determined by the above evaluation method for releasability of a rubber molded article having a complicated shape. Table 1 shows the results.

Example 2 and Comparative Examples 1-2
Evaluation was performed in the same manner as in Example 1, except that the types and amounts of the fluorine-containing copolymer, carbon black, cross-linking agent, and cross-linking aid shown in Table 1 were used. Table 1 shows the results.

From the results in Table 1, it is clear that the fluororubber molded article has excellent tear strength and bending fatigue resistance.

1: molded body 12, 22: convex part 21: primer valve 23: discharge side (engine side) hose 24: suction side (fuel tank side) hose H1: height of molded body convex part W1: molded body convex part width of

Claims (4)

Having a crosslinked fluororubber layer obtained by crosslinking a composition containing a fluorine-containing copolymer having a glass transition temperature of 25° C. or lower,
The fluorine-containing copolymer includes vinylidene fluoride and the following general formula (1):
_CH2 =CFRf (1)
(In the formula, Rf is a linear or branched fluoroalkyl group having 1 to 12 carbon atoms.)
A complex-shaped molded article characterized by being a copolymer consisting of a fluorine-containing monomer (1) represented by
The complicated-shaped molded article is a molded article having one or more projections projecting in the outer peripheral direction of a cylinder, and is a complicated-shaped molded article that is a primer bulb . The fluoropolymer includes vinylidene fluoride and the following general formula (1):
_CH2 =CFRf (1)
(In the formula, Rf is a linear or branched fluoroalkyl group having 1 to 12 carbon atoms.)
A copolymer consisting of a fluoromonomer (1) represented by and other monomers copolymerizable therewith, wherein the molar ratio of vinylidene fluoride units/fluoromonomer (1) units is 85/15 to 20/80, and the other monomer unit accounts for 0 to 50 mol % of the total monomer units. 3. The complex-shaped molded article according to claim 1, wherein the composition contains a cross-linking agent. 4. The complex-shaped molded article according to claim 3, wherein the cross-linking agent is an organic peroxide and the composition contains a polyfunctional co-cross-linking agent.

Images