JP2000007732A - Fluoroelastomer and preparation thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluoroelastomer which is free of a hexafluoropropene copolymer unit and has a high oil additive resistance and a preparation process thereof. SOLUTION: A fluoroelastomer has a copolymer composition of 30 to 60 mol.% vinylidene fluoride, 10 to 40 mol.% tetrafluoroethylene, 10 to 30 mol.% chlorotrifluoroethylene, 5 to 15 mol.% ethylene and, if required, 5 to 15 mol.% perfluoro(methyl vinyl ether). This fluoroelastomer is prepared by allowing vinylidene fluoride, tetrafluoroethylene, chlorofluoroethylene, ethylene and, if required, perfluoro(methyl vinyl ether) to undergo a copolymerization reaction in the presence of a bromine- or iodine-containing monomer compound and a compound containing iodine and bromine at 55 deg.C or lower.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a fluoroelastomer and a method for producing the same. More specifically, the present invention relates to a fluoroelastomer effectively used as a molding material for an additive-resistant oil sealing material and a method for producing the same.

[0002]

2. Description of the Related Art JP-A-6-122729 discloses that 4-75 mol% of vinylidene fluoride, preferably 10-70 mol%, more preferably 20-70 mol%, hexafluoropropene, pentafluorovinyl ether, At least one of pentafluoropropene and chlorotrifluoroethylene 12
~ 40 mol%, preferably 15-30 mol%, more preferably 18
To 27 mol%, C ₄ olefins of less than 2 to 35 mol%, (more) preferably 4 to 30 mol% and tetrafluoroethylene 2-6
0 mol%, preferably 4 to 50 mol%, more preferably 4 to 40 mol%
Higher molecular weight fluoroelastomer-based copolymers are described.

[0003] The invention is disclosed in Japanese Patent Application Laid-Open No. 6-248027.
In this publication, this fluoroelastomer-based copolymer consisting of units of vinylidene fluoride, hexafluoropropene, tetrafluoroethylene and olefins is highly resistant to bases, especially amine-containing oils, and has a high degree of elasticity and processing properties. Although peroxide or ion vulcanization is possible, vulcanization systems containing a highly reactive accelerator are generally required in the latter case.

JP-A-6-248027 discloses a fluoroelastomer copolymer having the following three types of copolymers which has resistance to a base and is particularly suitable for O-ring production. Have been. (1) Vinylidene fluoride 47-80 mol% Hexafluoropropene and / or perfluoro (alkyl vinyl ether) 16-30 mol% Hydrogenated olefin up to C ₂ -C ₄ 2-25 mol% (2) Vinylidene fluoride 42 8080 mol% perfluoro (alkyl vinyl ether) 16-30 mol% Hydrogenated olefin up to C ₂ -C ₄ 2-30 mol% (3) vinylidene fluoride 70-98 mol% hexafluoropropene and / or perfluoro ( alkyl vinyl ethers) 0 to 16 mol% C ₂ -C hydrogenation up to ₄ olefin 1 to 30 mol%

In a practical example, a fluoroelastomer copolymer having a copolymer composition of 75 to 60 mol% of vinylidene fluoride, 20 mol% of hexafluoropropene and 5 to 20 mol% of ethylene is disclosed. The obtained fluoroelastomer-copolymer does not contain tetrafluoroethylene monomer units, is capable of ionic vulcanization, has high elastomer properties even at low temperatures, and has excellent properties such as shaft seals, fuel hoses and general It is said to be particularly suitable for the production of O-rings in addition to the production of sealing devices.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a fluoroelastomer which does not contain hexafluoropropene copolymerized units and has excellent additive oil resistance and a method for producing the same.

[0007]

SUMMARY OF THE INVENTION The object of the present invention is as follows.
Vinylidene fluoride 30-60 mol%, tetrafluoroethylene 10-40 mol%, chlorotrifluoroethylene 10-30 mol%, ethylene 5-15 mol% and perfluoro (methyl vinyl ether) 5-15 mol% if necessary Which is achieved by copolymerization of vinylidene fluoride, tetrafluoroethylene, chlorofluoroethylene, ethylene and, if necessary, perfluoro (methyl vinyl ether).
In the presence of a bromine-containing or iodine-containing monomer compound and an iodine-containing bromine compound at a temperature of 55 ° C. or lower.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In an additive oil, an additive for improving the extreme pressure properties, such as amines, sulfides, thiols, etc., rust preventive properties, dispersibility and detergency is generally added to a base oil. . These compounds cause a double bond to be generated by a dehydrofluorination reaction or an addition reaction to the generated double bond with a fluoroelastomer, and an engine oil, a gear oil, a transmission oil, etc. to which these compounds are added. Is believed to be the cause of the degradation of the fluoroelastomer that comes into contact with the base oil.

The present inventors have found that the main cause of such deterioration is in the chain of vinylidene fluoride and hexafluoropropene, and a fluoroelastomer having a specific composition containing no hexafluoropropene as a copolymerized unit has been added. It was found to be excellent in oiliness.

The fluoroelastomer according to the present invention contains vinylidene fluoride in an amount of 30 to 60 mol%, preferably 35 to 50 mol.
%, 10 to 40 mol% of tetrafluoroethylene, preferably
20-35 mol%, chlorotrifluoroethylene 10-30 mol%, preferably 10-28 mol%, ethylene 5-15 mol%,
Preferably 7-13 mol% and optionally perfluoro
(Methyl vinyl ether) 5 to 15 mol%, preferably 7-1
It has a composition of 3 mol% copolymerized.

[0011] If the copolymerization ratio of vinylidene fluoride is higher than this, the oil resistance is remarkably reduced, while if the copolymerization ratio is lower than this, the cold resistance deteriorates.
If the copolymerization ratio of tetrafluoroethylene is higher than this, the cold resistance will deteriorate, while if the copolymerization ratio is lower than this, compression set characteristics and solvent resistance will decrease. If the copolymerization ratio of chlorotrifluoroethylene is higher than this, the heat resistance becomes remarkably inferior. On the other hand, if the copolymerization ratio is lower than this, the elastomeric property is impaired and not only becomes resinous, but also becomes resistant. Additive oiliness is not improved. If the copolymerization ratio of ethylene is higher than this, the elastomeric property is impaired and the resin becomes resinous, while if the copolymerization ratio is lower than this, the oil resistance of additives and the cold resistance are not improved. Further, further copolymerization of perfluoro (methyl vinyl ether) is disadvantageous in terms of cost.

In the quaternary or quaternary copolymer, for the main purpose of further cost reduction, fluorine having a degree of not impairing the copolymerization reaction and not deteriorating the vulcanization properties (about 20 mol% or less) is used. It is also possible to copolymerize olefins, various olefin compounds or vinyl compounds. As the fluorinated olefin, for example, monofluoroethylene, trifluoroethylene, trifluoropropylene, pentafluoropropylene, hexafluoroisobutylene, chlorotrifluoroethylene, dichlorodifluoroethylene, etc. are used, and as the olefin compound or vinyl compound, for example, Ethylene, propylene, 1-butene, isobutylene, methyl vinyl ether, ethyl vinyl ether, butyl vinyl ether, cyclohexyl vinyl ether, vinyl acetate, vinyl propionate, vinyl chloride,
Vinylidene chloride, trifluorostyrene and the like are used. Of these, at least one of trifluoroethylene, chlorotrifluoroethylene, methyl vinyl ether and the like is preferably used.

The copolymerization reaction can be carried out by any polymerization method such as emulsion polymerization, suspension polymerization, solution polymerization and bulk polymerization, but the emulsion polymerization method is preferred from the viewpoint of increasing the degree of polymerization and economy. Emulsion polymerization reaction, using a water-soluble inorganic peroxide such as ammonium persulfate or a redox system thereof and a reducing agent as a catalyst, ammonium perfluorooctanoate, ammonium perfluoroheptanoate, ammonium perfluorononanoate, or a mixture thereof, Preferably using ammonium perfluorooctanoate as emulsifier, generally at a pressure of about 0-20 MPa, preferably about 0-10 MPa
a, The reaction is carried out at a temperature of about 0 to 100 ° C, preferably about 20 to 55 ° C. When the polymerization temperature is set to 55 ° C. or lower, the obtained fluoroelastomer can be obtained with improved releasability from a mold at the time of vulcanization molding and improved adhesion of a rubber coat layer to a metal plate. At that time, in order to adjust the pH in the polymerization system, phosphate (Na ₂ HPO ₄ , NaH ₂ PO ₄ , KH ₂ PO ₄ etc.) or borate (N
a ₂ B ₂ O ₇ ) or an electrolyte having a buffering capacity, or NaOH or the like.

This copolymerization reaction is carried out in the presence of a bromine-containing or iodine-containing monomer compound and an iodine-containing bromine compound, preferably an iodine-containing bromine compound represented by the general formula RBrnIm.

Examples of the bromine-containing monomer compound used for forming the cross-linking site include vinyl bromide and 1-bromo-2,2
-Difluoroethylene, bromotrifluoroethylene,
Perfluoroallyl bromide, 4-bromo-1,1,2-trifluorobutene, 4-bromo-3,3,4,4-tetrafluorobutene, 4-bromo-1,1,3,3,4,4 -Hexafluorobutene,
Bromotrifluoroethylene, 4-bromo-3-chloro-1,1,
3,4,4-pentafluorobutene, 6-bromo-5,5,6,6-tetrafluorohexene, 4-bromoperfluorobutene-1,
A brominated vinyl compound such as 3,3-difluoroallyl bromide or a brominated olefin can be used, but a bromine group-containing vinyl ether represented by the following general formula is preferably used. _{BrRf-O-CF = CF 2} BrRf: bromine-containing perfluoro lower alkyl group

Such a bromine group-containing vinyl ether includes, for example, CF ₂ BrCF ₂ OCF = CF ₂ , CF ₂ Br (CF ₂ ) ₂ OCF = CF ₂ ,
CF ₂ Br (CF ₂ ) ₃ OCF = CF ₂ , CF ₃ CFBr (CF ₂ ) ₂ OCF = CF ₂ , CF ₂ Br
(CF ₂ ) ₄ OCF = CF _{2 and the} like are used, and details of these compounds are described in US Pat. No. 4,745,165.

Other than these, the general formula ROCF = CFBr or R is described in US Pat. No. 4,564,662.
A bromine group-containing vinyl ether represented by OCBr = CF ₂ (R: lower alkyl group or fluoroalkyl group) can also be used.

Examples of the iodine-containing monomer compound include iodotrifluoroethylene, 1,1-difluoro-2-iodoethylene, perfluoro (2-iodoethylvinyl ether), vinyl iodide and the like.

These bromine-containing or iodine-containing monomer compounds are used in an amount of about 0.01 to 2 mol%, preferably about 0.01 to 2 mol%, based on the total amount of vinylidene fluoride, tetrafluoroethylene, perfluoro (alkyl vinyl ether) and hexafluoropropene. It is used in a ratio of 0.03 to 1 mol%. If the proportion is lower than this, the compression set characteristics of the obtained vulcanizate deteriorate, while if it is used at a higher proportion, the elongation of the vulcanizate decreases.

In the formula, RBrnIm (where R is a fluorohydrocarbon group, a chlorofluorohydrocarbon group, a chlorohydrocarbon group or a hydrocarbon group, and n and m are each 1
Or 2) can act as a chain transfer agent and improve the processability by adjusting the molecular weight.

The iodine-containing bromine compound represented by the above general formula is selected from those which do not lose their effect by causing a side reaction under polymerization conditions, and the R group is generally a fluorohydrocarbon group having 1 to 10 carbon atoms, Selected from a chlorofluorohydrocarbon group, a chlorohydrocarbon group or a hydrocarbon group, and any group is -O
-, - S -, = NR , -COOH, -SO 2, -SO 3 H, may be bonded functional group such as -PO ₃ H.

As such an iodine-containing bromine compound, a saturated or unsaturated, aliphatic or aromatic compound, preferably one in which n and m are each 1 is used. When n and / or m are 2, the fluoroelastomer to be formed has a three-dimensional structure, and thus it is desired that the fluoroelastomer be used within a range where processability is not impaired.

Examples of the linear iodine-containing bromine compound include 1-bromo-2-iodoperfluoroethane and 1-bromo-3-
Iodoperfluoropropane, 1-bromo-4-iodoperfluorobutane, 2-bromo-3-iodoperfluorobutane, 1-bromo-2-iodoperfluoro (2-methylpropane), monobromomonoiodoperfluorocyclobutane , Monobromomonoiodoperfluoropentane, monobromomonoiodoperfluoro-n-octane, monobromomonoiodoperfluorocyclohexane, 1-bromo-1
-Iodo-2-chloroperfluoroethane, 1-bromo-2-iodo-2-chloroperfluoroethane, 1-iodo-2-bromo
2-chloroperfluoroethane, 1,1-dibromo-2-iodoperfluoroethane, 1,2-dibromo-2-iodoperfluoroethane, 1,2-diiodo-2-bromoperfluoroethane, 1- Bromo-2-iodo-1,2,2-trifluoroethane, 1-
Iodo-2-bromo-1,2,2-trifluoroethane, 1-bromo
2-iodo-1,1-difluoroethane, 1-iodo-2-bromo-
1,1-difluoroethane, 1-bromo-2-iodo-1-fluoroethane, 1-iodo-2-bromo-1-fluoroethane, 1-bromo-2-iodo-1,1,3,3,3- Pentafluoropropane, 1-iodo-2-bromo-1,1,3,3,3-pentafluoropropane, 1-
Bromo-2-iodo-3,3,4,4,4-pentafluorobutane, 1-
Iodo-2-bromo-3,3,4,4,4-pentafluorobutane, 1,
4-dibromo-2-iodoperfluorobutane, 2,4-dibromo-1-iodoperfluorobutane, 1,4-diiodo-2-bromoperfluorobutane, 1,4-dibromo-2-iodo-3,3 ,Four,
4-tetrafluorobutane, 1,4-diiodo-2-bromo-3,3,
4,4-tetrafluorobutane, 1,1-dibromo-2,4-diiodoperfluorobutane, 1-bromo-2-iodo-1-chloroethane, 1-iodo-2-bromo-1-chloroethane, 1- Bromo-2
-Iodo-2-chloroethane, 1-bromo-2-iodo-1,1-dichloroethane, 1,3-dibromo-2-iodoperfluoropropane, 2,3-dibromo-2-iodoperfluoropropane,
1,3-diiodo-2-bromoperfluoropropane, 1-bromo-2-iodoethane, 1-bromo-2-iodopropane, 1-iodo-2-bromopropane, 1-bromo-2-iodobutane, 1-
Iodo-2-bromobutane, 1-bromo-2-iodo-2-trifluoromethyl-3,3,3-trifluoropropane, 1-iodo-
2-bromo-2-trifluoromethyl-3,3,3-trifluoropropane, 1-bromo-2-iodo-2-phenylperfluoroethane, 1-iodo-2-bromo-2-phenylperfluoroethane, 3-bromo-4-iodoperfluorobutene-1, 3-iodo-4-bromoperfluorobutene-1, 1-bromo-4-iodoperfluorobutene-1, 1-iodo-4-bromoperfluorobutene- 1,3-bromo-4-iodo-3,4,4-trifluorobutene-1,4-bromo-3-iodo-3,4,4-trifluorobutene
-1,3-bromo-4-iodo-1,1,2-trifluorobutene-1,
4-bromo-5-iodoperfluoropentene-1,4-iodo-
5-bromoperfluoropentene-1, 4-bromo-5-iodo-
1,1,2-trifluoropentene-1,4-iodo-5-bromo-1,
1,2-trifluoropentene-1, 1-bromo-2-iodoperfluoroethyl perfluoromethyl ether, 1-bromo
2-iodoperfluoroethyl perfluoroethyl ether, 1-bromo-2-iodoperfluoroethyl perfluoropropyl ether, 2-bromo-3-iodoperfluoropropyl perfluorovinyl ether, 1-bromo-2-
Iodoperfluoroethyl perfluorovinyl ether, 1-bromo-2-iodoperfluoroethyl perfluoroallyl ether, 1-bromo-2-iodoperfluoroethyl methyl ether, 1-iodo-2-bromoperfluoroethyl ethyl ether, 1 -Iodo-2-bromoethylethyl ether, 1-bromo-2-iodoethyl-2'-chloroethylether and the like. These iodine-containing bromine compounds can be appropriately produced by a known method. For example, a monobromomonoiodo fluorine-containing olefin can be obtained by reacting iodine bromide with a fluorine-containing olefin.

Examples of the aromatic iodine-containing bromine compound include benzene 1-iodo-2-bromo and 1-iodo-3-
Bromo, 1-iodo-4-bromo, 3,5-dibromo-1-iodo,
3,5-diiodo-1-bromo, 1- (2-iodoethyl) -4- (2-bromoethyl), 1- (2-iodoethyl) -3- (2-bromoethyl), 1- (2-iodoethyl)- 4- (2-bromoethyl), 3,5-bis (2-bromoethyl) -1- (2-iodoethyl), 3,5-bis (2-
(Iodoethyl) -1- (2-bromoethyl), 1- (3-iodopropyl) -2- (3-bromopropyl), 1- (3-iodopropyl) -3
-(3-bromopropyl), 1- (3-iodopropyl) -4- (3-bromopropyl), 3,5-bis (3-bromopropyl) -1- (3-iodopropyl), 1- ( 4-iodobutyl) -3- (4-bromobutyl), 1- (4-iodobutyl) -4- (4-bromobutyl), 3,5-bis (4-iodobutyl) -1- (4-bromobutyl), 1- (2-Iodoethyl) -3- (3-bromopropyl), 1- (3-iodopropyl)
-3- (4-bromobutyl), 3,5-bis (3-bromopropyl) -1-
(2-iodoethyl), 1-iodo-3- (2-bromoethyl), 1-
Iodo-3- (3-bromopropyl), 1,3-diiodo-5- (2-bromoethyl), 1,3-diiodo-5- (3-bromopropyl), 1-
Bromo-3- (2-iodoethyl), 1-bromo-3- (3-iodopropyl), 1,3-dibromo-5- (2-iodoethyl), 1,3-dibromo-5- (3-iodopropyl )), 1-iodo-2-bromo, 1-iodo-3-bromo, 1-iodo-4-bromo, 3,5-dibromo-1-iodo, 3,5-perfluorobenzene
Each substituted product such as diiodo-1-bromo is used.

These iodine-containing bromine compounds readily undergo radical cleavage of iodine and bromine by the action of an organic peroxide radical generating source during a polymerization reaction, and the radicals generated therein have high reactivity, so that a monomer is added. Growth reaction
Thereafter, the reaction is stopped by extracting iodine and bromine from the iodine-containing bromine compound to give a fluoroelastomer having iodine and bromine bonded to molecular terminals. The iodine and bromine atoms attached to the molecular terminals
It also has a function as a crosslinking site during peroxide vulcanization.

The iodine-containing bromine compound is generally combined with the obtained fluoroelastomer so as to have about 5% by weight or less, generally about 0.001 to 5% by weight, and preferably about 0.01 to 3% by weight as iodine and bromine, respectively. .

The fluoroelastomer according to the present invention comprises
0.05 to 3 dl / g, preferably about 0.1 to 2 dl / g ηsp / c (35 ° C,
(In methyl ethyl ketone) having, conventionally known various vulcanization methods, such as a peroxide vulcanization method using an organic peroxide, a polyamine vulcanization method using a polyamine compound, a polyol vulcanization method using a polyhydroxy compound or radiation, Although curing can be performed by irradiation with an electron beam or the like, the vulcanization method using a peroxide-based cross-linking agent among these vulcanizates shows that the cured elastomer has good resistance to amine-added oil. This is a particularly preferable method.

Examples of the organic peroxide used in the peroxide vulcanization method include 2,5-dimethyl-2,5-bis (tert-butylperoxy) hexane and 2,5-dimethyl-2,5-bis (number 3
Butylpeoxy) hexyne-3, benzoyl peroxide, bis (2,4-dichlorobenzoyl) peroxide, dicumyl peroxide, ditertiary butyl peroxide, tertiary butylcumyl peroxide, tertiary butylperoxybenzene, 1 1,1-bis (tert-butylperoxy) -3,5,5-trimethylcyclohexane, 2,5-dimethylhexane-2,5-dihydroxyperoxide, α, α′-bis (tert-butylperoxy)- p-diisopropylbenzene, 2,5-dimethyl-2,5-di
(Benzoylperoxy) hexane, tertiary butylperoxyisopropyl carbonate and the like are used.

In the peroxide vulcanization method using these organic peroxides, a polyfunctional unsaturated compound such as tri (meth) allyl isocyanurate or the like is usually used as a co-crosslinking agent.
Tri (meth) allyl cyanurate, triallyl trimellitate, N, N'-m-phenylenebismaleimide, diallyl phthalate, tris (diallylamine) -s-triazine, triallyl phosphite, 1,2-polybutadiene, ethylene glycol Diacrylate, diethylene glycol diacrylate and the like are used in combination.

The above components to be added to the peroxide vulcanization system generally contain about 0.1 to 10 parts by weight, preferably about 0.5 to 5 parts by weight, of an organic peroxide per 100 parts by weight of the fluoroelastomer.
The co-crosslinking agent is used in an amount of about 0.1 to 10 parts by weight, preferably about 0.5 to 5 parts by weight, respectively.

In the composition comprising the above components, inorganic fillers such as carbon black and silica, ZnO, CaO, Ca (O
H) ₂ , acid acceptors such as MgO, PbO, synthetic hydrotalcite,
Various pigments, processing aids such as polyethylene glycol monomethyl ether and crown ether, RfO [OCF (CF ₃ ) CF
₂ O] nRf ′, RfO [CF (CF ₃ ) CF ₂ O] p (CF ₂ CF ₂ O) q (CF ₂ O) rRf ′,
RfO (CF ₂ CF ₂ O) n (CF ₂ O) mRf ′, RfO (CF ₂ CF ₂ CF ₂ O) nRf ′ [R
f, Rf ': perfluoroalkyl group], with-(CFXOC
_{F 2) a (CF 2)} b (CF 2 OCFX) c-: perfluoroalkylene ether triazine oligomers with [X F or CF ₃ group]
(See JP-A-7-285948), a plasticizer, a stabilizer, and other necessary compounding agents are appropriately compounded.

The fluoroelastomer of the present invention may also contain other substances having peroxide crosslinking properties, such as silicone oil, silicone rubber, fluorosilicone rubber,
Fluorophosphazenecom, ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer, ethylene-propylene (-diene) copolymer rubber, acrylonitrile
-Blend with butadiene copolymer rubber, acrylate rubber, etc. and co-crosslink.

The composition is prepared by kneading using a roll, kneader, Banbury mixer, or the like.
Crosslinking of it is performed by heating at about 140-220 ° C for about 5-60 minutes. When performing secondary vulcanization, in an inert atmosphere such as air or nitrogen gas atmosphere, about 150 to 2
It is preferably performed at 50 ° C. for about 5 to 50 hours.

[0034]

The fluoroelastomer according to the present invention comprises:
Not only is it excellent in terms of mold releasability from the mold during vulcanization molding, adhesiveness between the metal plate and the rubber coat layer in a fluororubber-coated metal plate used as a gasket material, etc. A vulcanizate which is satisfactory in terms of engine oil properties and amine-added oil resistance is provided. In particular, it has excellent resistance to metal adhesion to the new SJ-class engine oil. Therefore, it can be effectively used as a vulcanization molding material for a valve stem seal or an oil pan gasket.

[0035]

Next, the present invention will be described with reference to examples.

Example 1 After replacing the inside of a stainless steel autoclave having a capacity of 3 L with nitrogen gas, the autoclave was degassed, and then there was 104 g of vinylidene fluoride [VdF], 15 g of tetrafluoroethylene [TFE], 15 g of chlorotrifluoroethylene [CTFE], 42 g of par Fluoro (methyl vinyl ether) [FMVE] 74 g Ethylene [E] 3.4 g CF ₂ = CHBr 3.5 g ICF ₂ CF ₂ Br 2.7 g Ammonium perfluorooctanoate 3 g Na ₂ HPO ₄ 4 g Water 1500 ml was charged.

After the internal temperature of the autoclave was raised to 50 ° C., 2 g of ammonium persulfate was added to start the polymerization reaction. While maintaining the internal pressure of the autoclave to ^{21~22Kg / cm 2 G, VdF127g,} TFE165g, CTFE84g, FMVE75g and E16.8g
Was mixed over 18 hours. After completion of the dispensing, the mixture was cooled to room temperature over 4 hours, an aqueous sodium chloride solution was added to 2170 g of the collected aqueous latex, and the coagulated product was separated, washed with water and dried to obtain 669 g of fluoroelastomer A (95% polymerization rate). Obtained.

The obtained fluoroelastomer A was analyzed by elemental analysis to find that VdF 42.8 mol% (44.8 mol% charged), TFE 23.1.
Mol% (22.2 mol% charged), 12.8 mol% CTFE (13.3 mol% charged), 10.8 mol% FMVE (11.1 mol% charged), and E10.5 mol% (8.9 mol% charged). Was.

Example 2 The same procedure as in Example 1 was carried out except that the initial charge of the comonomer and the total charge ratio of the initial charge VdF 104 g 103 g 40 mol% TFE 25 g 217 g 30 mol% CTFE 37 g 57 g 10 mol% FMVE 75 g 59 g 10 mol% E 3.4 g A copolymerization reaction was carried out using 19 g of 10 mol%.

The obtained fluoroelastomer B weighed 652 g.
(Polymerization rate 93%), VdF 38.0 mol%, TFE 31.2 mol%, CTFE10.
It had a copolymer composition of 8 mol%, FMVE 9.4 mol% and E10.6 mol%.

Example 3 The same procedure as in Example 1 was carried out except that the initial charge of the comonomer and the total charge ratio of the initial charge VdF 93 g 124 g 40 mol% TFE 45 g 167 g 25 mol% CTFE 99 g 148 g 25 mol% E 3 g 21 g 10 mol% A copolymerization reaction was performed.

The obtained fluoroelastomer C weighed 675 g.
(Polymerization rate 96%), VdF 38.0 mol%, TFE26.3 mol%, CTFE26.
It had a copolymer composition of 2 mol% and E9 mol%.

[0043] In Comparative Example 1 Example 1, the co-monomer initially charged amount hydrofinishing inclusive total charge percentage VdF 53 g 85 g 28 mol% TFE 40 g 160 g 26 mol% HFP 65 g 28 g 8 mol% FMVE 110g 107g 17 mol% E 9.5 g A copolymerization reaction was carried out using 21 g of 36 g.

The obtained fluoroelastomer D weighed 607 g.
(Polymerization rate 88%), VdF 28 mol%, TFE 28 mol%, HFP (hexafluoropropene) 6 mol%, FMVE 16 mol% and E22 mol%
Having a copolymer composition of

Reference Examples (Nos. 1 to 4) 100 parts by weight of the fluoroelastomer obtained in each of the above Examples and Comparative Examples was added to 30 parts by weight of MT carbon black, 6 parts by weight of zinc oxide, and 4 parts by weight of triallyl isocyanurate. Parts by weight and organic peroxide (Aluchem-Yoshitomi product Lluperco-101XL)
3 parts by weight were added and kneaded with a two-roll mill. The kneaded product was subjected to press vulcanization at 180 ° C. for 10 minutes and oven vulcanization at 200 ° C. for 22 hours.

In No. 5, 100 parts by weight of fluoro rubber (Afras 200 manufactured by Asahi Glass Co., Ltd .; terpolymer rubber of tetrafluoroethylene-vinylidene fluoride-propylene) was mixed with 30 parts by weight of MT carbon black and 1 part by weight of calcium stearate. Part, triallyl isocyanurate 4 parts by weight and organic peroxide (Nippon Oil & Fats product Peroximon F40) 3 parts by weight, kneaded product obtained, 170 ° C., press vulcanization for 20 minutes and 230 ° C., 22 hours Oven vulcanization was performed.

With respect to the obtained vulcanized product, the following items were measured. Normal properties: JIS K-6301 compliant Low temperature properties (TR-10): ASTM D-1329 Adhesion: Bonded steel sheet (20 × 40 × 1 mm) immersed in a 1% by weight vinylmethoxysilane aqueous solution at 40 ° C. for 3 minutes After, 150 ℃
And dried for 3 minutes. After wrapping half the area of this test piece with aluminum foil, 100 × 1
After placing in a mold having a space volume of 00 x 2 mm and performing vulcanization bonding of the fluororubber compound at 180 ° C for 4 minutes, 200
Oven vulcanization was performed at ℃ for 20 hours, and the rubber was peeled off from the metal bonding part and the adhesion was evaluated. (Rubber residual rate) Rubber residual rate when rubber was peeled from metal plate (Interfacial foaming) Number of traces of foam remaining on the metal surface when rubber is peeled off from the board A: 0 to 1, B: 2 to 5, C: 5 or more Engine oil resistance: 175 in TOYOTA Castle Motor Oil Clean SJ 10W-30 Changes in physical properties after immersion at 168 ° C for 168 hours and elongation when cracks occur

The results obtained, together with the type of fluoroelastomer used, are shown in the following table. Table No.1 No.2 No.3 No.4 No.5 [Fluoroelastomer] ABCD Afras [Normal physical properties] Hardness (JIS A) (pts) 71 74 76 71 70 100% modulus (MPa) 6.1 7.2 7.5 8.5 7.5 Strength at break (MPa) 12.9 15.8 13.8 19.0 17.0 Elongation at break (%) 200 180 160 180 190 [Low temperature properties: TR-10] (℃) -14.0 -8.6 -5.3 -7.5 -8.0 [Adhesiveness] Rubber residue Rate (%) 90 90 90 70 50 Interface foam AAACC [Engine oil resistance] Change in hardness (pts) +2 +2 +3 +2 +2 Rate of change in strength at break (%) +5 -30 -35 -20- 40 Elongation change at break (%) -40 -35 -55 -55 -35 Elongation at crack occurrence (%) 80 85 60 40 70

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C08L 27/16 C08L 27/16 C09K 3/10 C09K 3/10 M // (C08F 214/22 214: 26 214: 24 210: 02 216: 14) F-term (reference) 4H017 AA03 AA31 AB12 AC14 AC16 AE02 AE05 4J002 BD121 BD141 BD151 EK006 EK036 FD146 GJ02 4J011 AA05 AB02 BA03 DA01 KA01 KB02 KB03 NA12 NB04 4J100 AA02T AC31P ACTQB CB31 HC34 HC36 HC63

Claims (7)

[Claims] 1. A fluoroelastomer having a copolymer composition of 30 to 60 mol% of vinylidene fluoride, 10 to 40 mol% of tetrafluoroethylene, 10 to 30 mol% of chlorotrifluoroethylene and 5 to 15 mol% of ethylene. 2. The fluoroelastomer according to claim 1, wherein 5 to 15 mol% of perfluoro (methyl vinyl ether) is further copolymerized. 3. The fluoroelastomer according to claim 1, which is obtained by copolymerization in the presence of a bromine-containing or iodine-containing monomer compound and an iodine-containing bromine compound. 4. A method according to claim 1, wherein vinylidene fluoride, tetrafluoroethylene, chlorotrifluoroethylene and ethylene are
The process for producing a fluoroelastomer according to claim 1, wherein the copolymerization reaction is carried out at a temperature of 55 ° C or less in the presence of a bromine-containing or iodine-containing monomer compound and an iodine-containing bromine compound. 5. The process for producing a fluoroelastomer according to claim 2, wherein the copolymerization reaction according to claim 4 is carried out using perfluoro (methyl vinyl ether) as a comonomer component. 6. A crosslinkable composition comprising the fluoroelastomer according to claim 1 and a peroxide crosslinking agent. 7. The crosslinkable composition according to claim 6, which is used as a molding material for an additive-resistant oil sealing material.