JPS63308008A - Production of fluorine-containing elastomer vulcanizable with peroxide - Google Patents

Abstract

PURPOSE:To obtain an elastomer capable of providing a vulcanized material having excellent processing properties, vulcanization characteristics and vulcanizing properties, having iodine and bromine introduced as crosslinking points into a fluorine-containing elastomer molecule, by polymerizing a fluorine- containing olefin in the presence of a compound containing iodine and bromide. CONSTITUTION:2-8C fluorine-containing olefin is polymerized alone or copolymerized usually with 2-6C olefinic compound and/or 4-8C fluorine- containing diene in the presence of a compound containing iodine and bromide shown by the formula RBrnIm (R is fluorohydrocarbon, chlorofluorohydrocarbon, chlorohydrocarbon or hydrocarbon; n and m are 1 or 2) to give the aimed elastomer. The amount of the compound containing iodine and bromine used is preferably an amount to give 0.001-5wt.% calculated as iodine and bromine of the compound bonded in the fluorine-containing elastomer. The polymerization reaction is preferably carried out in the presence of a redox polymerization initiator at 0-50 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing a peroxide vulcanizable fluorine-containing elastomer. For more details.

This invention relates to a method for producing a peroxide-curable fluorine-containing elastomer that has halogen atoms bonded in its molecules and uses these atoms as crosslinking points.

[Conventional technology]

In general, fluorine-containing elastomer vulcanizates have excellent heat resistance, solvent resistance, weather resistance, ozone resistance, and creep resistance, so they are used as sealing materials such as oil seals, packings, gaskets, and O-rings.

It is widely used industrially for diaphragms, hose linings, coatings, adhesives, etc.

Conventionally, a peroxide vulcanization method using an organic peroxide as a vulcanizing agent has been employed as one method for obtaining such a fluorine-containing diistomer vulcanizate.

In this case, the fluorine-containing elastomer used is one in which iodine or bromine is bonded as a crosslinking point. Some examples of these are described below, but all of them have the following problems.

JP-A-53-125,491 A method using an iodine compound represented by the general formula RfIx (Rf is a fluorohydrocarbon group or a chlorofluorohydrocarbon group).゜401
As described in the above publication, it is expensive and highly toxic, and the iodine bonded to the fluorine-containing elastomer is easily released under light irradiation.

JP-A No. 60-221,409 (2) A method using an iodine compound represented by the general formula RI, ~z (R is a hydrocarbon group having 1 to 3 carbon atoms) This iodine compound is inexpensive and is similar to the above-mentioned RfIx compound. Although it is less toxic, it is inferior in terms of vulcanization rate, heat resistance of the vulcanizate, and compression set.

JP-A-59-20,310 A method using a bromine compound represented by the general formula RBrx (R is a saturated aliphatic hydrocarbon group) This invention is described in JP-A-53-125,491. It shares some of the co-inventors with the invention of , and is said to have better performance than the iodine-bonded fluorine-containing elastomer. In fact, bromine-bonded fluorine-containing elastomers have good photostability, but are poor in vulcanization rate, heat resistance of vulcanizates, and compression set.

Japanese Patent Publication No. 54-1585 Nibrome trifluoroethylene, 4-brome-3°3.4
．． Fluorine-containing elastomers obtained by methods using brominated olefin compounds such as 4-tetroprobutene-1 tend to gel easily and have poor processability (flow characteristics), as well as poor elongation and compression set of the vulcanizate. It is also not sufficient in this respect.

JP-A-60-195,113 General formula ROCX=CYZ (One or two of X, Y and Z are selected from bromine and iodine.

The remainder is hydrogen, fluorine, or chlorine, and R is a chain or cyclic alkyl group, alkenyl group, or aryl group). 5 mol%
How to copolymerize this vinyl ether as a curing site monomer.

Although compounds substituted with both bromine and iodine can be selected from the above general formula, the same publication states that the halogen substituents represented by X, Y, and Z are either bromine or, to a lesser extent, iodine. Certain bromine- or iodine-containing vinyl ethers are described as being used as cure site monomers.

Also in the case of this method, the above-mentioned
The same drawbacks as the invention described in Publication No. 5 are observed.

[Problem that the invention seeks to solve]

The present inventors solve the problems seen in the above-mentioned prior art and produce a peroxide-vulcanizable fluorine-containing elastomer that can provide a vulcanized product with excellent processability, vulcanization properties, and vulcanized physical properties. As a result of intensive research on methods,
It has been found that such problems can be effectively solved by polymerizing a fluorine-containing olefin in the presence of an iodine-containing bromine compound and simultaneously introducing iodine and bromine as crosslinking points into the fluorine-containing elastomer molecule.

[Means for Solving the Problems] and [Operation] Therefore, the present invention relates to a method for producing a peroxide-vulcanizable fluorine-containing elastomer, and the production of the fluorine-containing elastomer is performed using the general formula RBrnIm (here, R. is a fluorohydrocarbon group, a chlorofluorohydrocarbon group, a chlorohydrocarbon group, or a hydrocarbon group, and n and m are both 1 or 2). This is carried out by homopolymerizing or copolymerizing the fluorine-containing olefins of ~8.

As the iodine-containing bromine compound represented by the above general formula,
The R group is selected from those that do not cause side reactions under polymerization conditions and lose their effectiveness, and the R group is generally selected from a fluorohydrocarbon group, a chlorofluorohydrocarbon group, a chlorohydrocarbon group, or a hydrocarbon group having 1 to 10 carbon atoms. Both groups are 10-1-S
-1=NR.

Functional groups such as -COOHl-8O2, -8o, Hl-PO, H, etc. may be bonded.

Such iodine-containing bromine compounds are saturated or unsaturated, chain-like or aromatic compounds, preferably n
and m of 1 are used. n and/
Alternatively, when m is 2, the produced fluorine-containing elastomer has a three-dimensional structure, so it is desirable to use it within a range that does not impair processability.

Examples of chain iodine-containing bromine compounds include 1-bromo-2-iodoperfluoroethane, 1-bromo-3-iodoperfluoropropane, 1-bromo-4-iodoperfluorobutane, 2-bromo-3- Iodoperfluorobutane, 1-bromo-2-iodoperfluoro(2-
methylpropane), monobromomoniodoperfluorocyclobutane, monobromomoniodoperfluoropentane, monobromomoniodoperfluoro-n-octane, monobromomoniodoperfluorocyclohexane, 1-bromo-1-iodo-2-chlor Perfluoroethane, 1-bromo-2-iodo-2-chloroperfluoroethane, 1-iodo-2-bromo-2-chloroperfluoroethane.

1.1-dibromo-2-iodoperfluoroethane, 1
, 2-dibromo-2-iodopurple oloethane, 1,
2-short-2-bromperfluoroethane, 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-iodo3,3,4,4゜4-pentafluorobutane, 1-iodo-2-bromo-3,3,4,4,4-pentafluorobutane, 1 , 4-dibromo-2-iodoperfluorobutane, 2,4-dibromo-1-iodoperfluorobutane, 1,4-short-2-bromoperfluorobutane, 1,4-dibromo-2-iodo-3, 3,4,4-tetrafluorobutane, 1゜4-short-2-bromo-
3,3,4,4-tetrafluorobutane, 1,1-dibromo-2,4-short perfluorobutane, 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-dibrom-2-iodoperfluoropropane, 2,3-dibrom-2-iodoperfluoropropane, 1°3-short-2-bromperfluoroethane, 1-bromo-2-iodoethane, 1 -Bromo-2-iodobropane, 51-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-bromperfluoroethane-1,1-bromo-4
-Iodoperfluorobutene-1,1-iodo-4-bromoperfluoroethane-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-bromperfluoropentene-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 perfluorovinylether, 1-bromo-2-iodoperfluoroethyl perfluorovinylether, 1-bromo-2-iodoperfluoroethyl perfluoroethyl ether, 1-bromo-2-iodoperfluoroethylmethyl ether,
1-iodo-2-bromoperfluoroethyl ethyl ether, 1-iodo-2-bromoethyl ethyl ether,
Examples include 1-bromo-2-iodoethyl-2'-chloroethyl ether. These iodine-containing bromine compounds can be produced by appropriately known methods. For example, by reacting a fluorine-containing olefin with iodine bromide, a monobromomonoiodine fluorine-containing olefin can be obtained.

Examples of aromatic iodine-containing bromine compounds include 1-iodo-2-brome, 1-iodo-3-brome, and 1-iodo-4-brome of benzene.

3,5-dibromo-1-iodo, 3,5-short-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-brombutyl), 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-brombutyl).

3.5-bis(3-bromopropyl)-1-(2-iodoethyl), 1-iodo-3-(2-bromoethyl)
, 1-iodo-3-(3-bromopropyl), 1.3-
Short-5-(2-bromoethyl), 1.3-short-5-(3-bromopropyl), 1-bromo-3-(
Substitutions such as 2-iodoethyl), 1-bromo-3-(3-iodopropyl), 1゜3-dibromo-5-(2-iodoethyl), 1゜3-dibromo-5-(3-iodopropyl), etc. body, 1-iodo-2 of perfluorobenzene
-brome, 1-iodo-3-brome, 1-iodo-4-
Substituents such as brome, 3,5-dibromo-1-iodo, and 3,5-short-1-brome are used.

These iodine-containing bromine compounds easily radically cleave iodine and bromine due to the action of an organic peroxide radical generator during the polymerization reaction, and the resulting radicals are highly reactive, resulting in monomer addition growth reactions. Thereafter, the reaction is terminated by abstracting iodine and bromine from the iodine-containing bromine compound, yielding a fluorine-containing elastomer in which iodine and bromine are bonded to the molecular ends.

In addition, the fluorine-containing elastomer produced in this way easily undergoes radical cleavage of iodine and bromine at the end of the molecule in the presence of a radical generating source, and the polymer radicals generated thereby have similar reactivity, so they can be polymerized multiple times. By carrying out this process, it is also possible to obtain segmented polymers depending on the type of polymerization monomer.

These iodine-containing bromine compounds are generally bonded to the molecular ends to give a fluorine-containing distomer that can efficiently achieve crosslinking, but they contain about 0.001 to 5 weight of iodine and bromine, respectively, in the resulting fluorine-containing elastomer. %, preferably about 0.01 to 3% by weight. If the amount of bonding is less than this, the crosslinking density of the fluorine-containing elastomer will be low, resulting in insufficient vulcanization. On the other hand, if the amount of bonding is greater than this, the rubber elasticity (elongation) and heat resistance of the vulcanizate will be poor. It starts to come.

The fluorine-containing olefin polymerized by the method of the present invention includes:
Those having 2 to 8 carbon atoms are preferred, such as vinylidene fluoride, tetrafluoroethylene, hexafluoropropene, pentafluoropropene, chlorotrifluoroethylene, methyl perfluorovinyl ether, ethyl perfluorovinyl ether, n- or iso-propyl perfluoro Vinyl ether, n-, iso- or tert-butyl perfluorovinyl ether, n- or iso-amyl perfluorovinyl ether, perfluoro(methyl vinyl ether), perfluoro(ethyl vinyl ether), perfluoro(n- or iso-propyl At least one of the following is mainly used: perfluoro (n-, iso- or tert-butyl vinyl ether), perfluoro (n- or iso-amyl vinyl ether), perfluoro (propoxypropyl vinyl ether), etc. Also used are vinyl fluoride, trifluoroethylene, perfluorocyclobutene, perfluoro(methylcyclopropene), hexafluoroisobutyne, 1,2,2-trifluorostyrene, perfluorostyrene, and the like.

These fluorine-containing olefins can also be copolymerized with an olefinic compound having 2 to 6 carbon atoms and/or a fluorine-containing diene having 4 to 8 carbon atoms.

Examples of olefinic compounds include those having 2 to 6 carbon atoms, such as unsaturated vinyl esters such as ethylene, propylene, butene, and vinyl acetate, and alkyl vinyl ethers such as methyl vinyl ether and ethyl vinyl ether. Copolymerization is carried out at a ratio of 0.0 to 50 mol%.

Further, as the fluorine-containing diene, for example, perfluoro-
1,3-butadiene, perfluoro-1°4-pentadiene, 1. l, 2-trifluoro-1,3-butadiene, 1,1.2-trifluoro-1,4-pentadiene,
1,1,2,3.3-pentafluoro-1,4-pentadiene, perfluoro-1,7-octadiene, perfluorodivinyl ether, perfluorovinyl perfluoroallyl ether, vinyl perfluoroallyl ether, perfluorovinyl Carbon number 4 such as vinyl ether
-8 are listed. These fluorine-containing dienes are
It is preferable to copolymerize so that it is present in the fluorine-containing distomer in a proportion of about 1 mol % or less. If the copolymer is copolymerized in a proportion larger than this, gelation of the copolymer elastomer will become significant, and processability (flow characteristics) and elongation of the vulcanizate will deteriorate.

Specific fluorine-containing olefin copolymers include hexafluoropropene-vinylidene fluoride copolymer, hexafluoropropene-vinylidene fluoride-tetrafluoroethylene ternary copolymer, and tetrafluoroethylene-vinylidene fluoride-perfluoroethylene copolymer. (methyl vinyl ether)
Ternary copolymer, tetrafluoroethylene-vinylidene fluoride-/<-fluoro(propyl vinyl ether) 3
Original copolymer.

Tetrafluoroethylene-perfluoro(propoxypropyl vinyl ether) copolymer, tetrafluoroethylene-perfluoro(methyl vinyl ether) copolymer, tetrafluoroethylene-propylene copolymer, tetrafluoroethylene-vinylidene fluoride-hexafluoropropene -Pentafluoropropene quaternary copolymer, tetrafluoroethylene-hexafluoropropene-vinylidene fluoride-perfluoro(methyl vinyl ether)
Quaternary copolymer, tetrafluoroethylene-hexafluoropropene-hexafluoroisobutyne terpolymer,
Tetrafluoroethylene-cyclohexyl vinyl ether copolymer, hexafluoropropene-vinylidene fluoride-chlorotrifluoroethylene terpolymer, vinylidene fluoride-tetrafluoroethylene-methyl perfluorovinyl ether terpolymer, vinylidene fluoride -Tetrafluoroethyl-n-butyl barfluorovinyl ether ternary copolymer, vinylidene fluoride-methyl perfluorovinyl ether-perfluoro(methyl vinyl ether) ternary copolymer, tetrafluoroethylene-
Methyl perfluorovinyl ether-perfluoro(methyl vinyl ether) terpolymer, vinylidene fluoride-hexafluoropropene-tetrafluoroethylene-
Methyl perfluorovinyl ether quaternary copolymer, tetrafluoroethylene-n-butyl perfluorovinyl ether-perfluoro(methyl vinyl ether) ternary copolymer, vinylidene fluoride-n-butyl purple vinyl ether copolymer, tetrafluoroethylene -Propylene-n-butyl perfluorovinyl ether terpolymer, tetrafluoroethylene-vinylidene fluoride-
Propylene-n-butyl perfluorovinyl ether 4
Examples include original copolymers.

The polymerization reaction is carried out using a fluorine-containing olefin or the above-mentioned comonomer in the presence of an iodine-containing bromine compound.

This is carried out by solution polymerization, suspension polymerization or emulsion polymerization using conventionally known methods.

In the case of solution polymerization, for example, organic peroxides, fluorine-containing organic peroxides, organic azo compounds, fluorine-containing organic azo compounds, etc. are used as polymerization initiators, or these polymerization initiators are combined with triethylaluminum, triethylboron, diethyl Perfluoro(1,2-dimethylcyclobutane),
Perfluoro(1,2-dichloroethane), perfluoro(1,2,2-trichloroethane), perfluorocyclohexane, perfluorotributylamine, α, ω
The polymerization reaction is carried out in a polymerization solvent with low chain transfer properties, such as -cybidroba-fluoropolymethylene, perfluoro(methoxypolyethoxyethane), perfluorocyclobutane, and tertiary butanol.

In the case of suspension polymerization, for example, organic peroxides, fluorine-containing organic peroxides, organic azo compounds, fluorine-containing organic azo compounds, etc. are used as polymerization initiators, or these polymerization initiators are combined with triethylaluminum, triethyl In the form of a redox system formed in combination with organometallic compounds such as boron and diethylzinc, and reducing agents such as tertiary amines and mercaptans.

The polymerization reaction is carried out using these as they are or as a solution dissolved in a solvent such as trifluorotrichloroethane, methylchloroform, dichlorotetrafluoroethane, difluorotetrachloroethane, etc., in a state in which 1,000 yen is dispersed in water.

In the case of emulsion polymerization, 1) Initiating water-soluble polymerization such as inorganic peroxides such as persulfate, hydrogen peroxide, and perchlorate, and organic peroxides such as tert-butyl hydroperoxide and disuccinyl peroxide. These polymerization initiators are also used as a redox system in combination with reducing agents such as sulfites, hyposulfites, ascorbic acid, ferrous salts, and sodium hydroxymethanesulfinate. Furthermore, the molecular weight of the fluorine-containing distomer can also be adjusted using a chain transfer agent such as methanol, ethanol, isopentane, ethyl acetate, diethyl malonate, carbon tetrachloride, or the like. Furthermore, an emulsifier such as a fluorine-containing carboxylate or a fluorine-containing sulfonate can also be used for the purpose of stably dispersing the polymer particles in the polymerization solution, increasing the polymer concentration, and preventing the polymer from adhering to the polymerization tank.

These various polymerization reactions are carried out at a temperature within a range in which the radical reaction proceeds and depolymerization of the resulting polymer does not occur, generally at a temperature of about -30 to 150°C. However, in the case of redox systems, the reaction takes place at a temperature of about 0 to 50°C,
When the reaction is carried out in such a low temperature range, thermal decomposition of the iodine-containing bromine compound can be suppressed, and the crosslinking density of the vulcanizate can be increased.6 There is no particular restriction on the polymerization pressure, and the desired polymerization can be achieved. A wide range of pressures can be employed depending on the rate and degree of polymerization, but generally about 1 to 100 kgf.
/cxt.

The fluorine-containing elastomer obtained by the method of the present invention.

Various conventionally known 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 an irradiation method using radiation, electron beam, etc. Among these methods, the peroxide vulcanization method allows the cured elastomer to have excellent mechanical strength and the structure of the crosslinking point to form stable carbon-carbon bonds (see the margin below), resulting in chemical resistance. This is a particularly preferred method because it provides a vulcanizate with excellent properties such as hardness and abrasion and solvent resistance.

Examples of organic peroxides used in the peroxide vulcanization method include 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-
Bis(tert-butylbioxy)hexyne-3, benzoyl peroxide, bis(2,4-dichlorobenzoyl)
Peroxide, dicumyl peroxide, di-tert-butyl peroxide, t-butyl cumyl peroxide, tert-butyl peroxybenzene, 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, tert-butylperoxyisopropyl carbonate, etc. are used.

In the peroxide vulcanization method in which these organic peroxides are used, polyfunctional unsaturated compounds such as tri(meth)allyl isocyanurate, tri(meth)allyl cyanurate, triallyl trimellitate are usually used as co-crosslinking agents. , N
, N'-m-phinidine bismaleimide, diallyl phthalate, tris(diallylamine)-S-triazine, triallyl phosphite, 1,2-polybutadiene, ethylene glycol diacrylate, diethylene glycol diacrylate, etc. are better. It is used in combination to obtain good vulcanization properties, mechanical strength, and compression set.

Depending on the purpose, divalent metal oxides or hydroxides such as calcium, magnesium,
Oxides or hydroxides of lead, zinc, etc. can also be used. These compounds also act as acid acceptors.

The above-mentioned components to be added to the peroxide vulcanization system generally include about 0.1 to 10 parts by weight of organic peroxide, preferably about 0.5 to 5 parts by weight, per 100 parts by weight of the fluorine-containing elastomer. 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, and the crosslinking aid is used in an amount of about 15 parts by weight or less.

The above-mentioned vulcanization system components may be mixed with the fluorine-containing elastomer as is and kneaded, or they may be diluted with carbon black, silica, clay, talc, diatomaceous earth, barium sulfate, etc., or mixed with the fluorine-containing elastomer. used as a masterbatch dispersion. In addition to the above-mentioned components, the formulation contains conventionally known fillers, reinforcing agents, plasticizers,
A lubricant, a processing aid, a pigment, etc. can also be blended as appropriate.

The fluorine-containing elastomer according to the present invention can be made from other substances having peroxide crosslinking properties, such as silicone oil, silicone rubber, fluorosilicone rubber, fluorophosphazenecomb, ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer. , ethylene-propylene(-diene) copolymer rubber, acrylonitrile-butadiene copolymer rubber, acrylic ester rubber, etc., and co-crosslinking can be carried out.

Vulcanization is performed by mixing the above-mentioned components by a commonly used mixing method such as roll mixing, kneader mixing, Banbury mixing, solution mixing, etc., and then heating the mixture.

Heating is generally performed at about 100 to 250°C for about 1 to 120 minutes, and then at about 150 to 300°C for 0.
This is carried out by secondary vulcanization which is carried out for about 30 hours.

〔Effect of the invention〕

The fluorine-containing elastomer obtained by the method of the present invention is
Not only is it superior in terms of processability, but it is also significantly improved in terms of vulcanization properties and vulcanization physical properties (mechanical strength, elongation, heat resistance, compression set, etc.) in peroxide vulcanization methods. , can be effectively used for various purposes as mentioned above.

〔Example〕

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

Example 1 1500 m of deionized water in an autoclave with an internal volume of 3 n
Q and ammonium perfluorooctanoate 7.5g
and fill the internal space with vinylidene fluoride/hexafluoropropene/tetrafluoroethylene (molar ratio 42/3).
8/20) The gas was sufficiently replaced with a mixed gas. Next, after pressurizing the internal pressure to 12 kg/dG with this mixed gas, 2.0 g of 1-bromo-2-iodoperfluoroethane was injected, and the internal temperature was raised to 80° C. while stirring. At this time, the internal pressure is 1
It becomes 6kg/cjG.

To this, 2 g of ammonium persulfate dissolved in 20 mQ of deionized water was added to start the polymerization reaction.As the reaction progressed, the pressure decreased, so when the internal pressure decreased to 15 kg ZaIG, vinylidene monofluoride/hexafluoropropane/ Tetrofluoroethylene (molar ratio 58/20/2
2) Repressurize to 16 kg/ajG with mixed gas, continue polymerization at a pressure of 15 to 16 kg/ajg, and after 3 hours, purge the unreacted mixed gas in the autoclave to stop the reaction. .

A 5% potassium alum aqueous solution was added to the resulting aqueous emulsion to coagulate the resulting polymer, which was then washed with water and dried.
08 g of rubbery polymer was obtained.

Example 2 In Example 1, instead of 1-bromo-2-iodoperfluoroethane, the same amount of 1-bromo-2-iodo-1
-Chloro-1,2,2-trifluoroethane was used and 462 g of rubbery polymer was obtained.

Example 3 In Example 1, vinylidene fluoride/hexafluoropropene mixed gas was used as the fluorine-containing monomer mixed gas,
In the initial charge, a molar ratio of 50150 was used, and in the partial addition, a molar ratio of 78/22 was used, yielding 475 g of a rubbery polymer.

Example 4 In Example 1, the amount of 1-bromo-2-iodoperfluoroethane used was changed to 1.6 g, and this was used together with 10.2 g of 3-brom-4-iodoperfluorobutene, resulting in 492 g of A rubbery polymer was obtained.

Example 5 In Example 1, vinylidene fluoride/tetrafluoroethylene/perfluoromethyl perfluorovinylether (molar ratio 69/2) was used as the fluorine-containing monomer mixed gas.
0/11) gas mixture was used consistently and 426 g of rubbery polymer was obtained.

Comparative Example 1 In Example 1, 1-bromo-2-iodoperfluoroethane was not used and the amount of ammonium persulfate used was 3
In addition to using 5 g of acetone as a chain transfer agent, 562 g of a rubbery polymer was obtained.

Example 6 1500 m of deionized water in an autoclave with an internal volume of 3Q
M and ammonium perfluorooctanoate 7.5g
5 g of disodium phosphate dodecahydrate dissolved in 20 mA deionized water and 5 g of sodium hydroxide were added to adjust the pH to approximately 10. Then, 1 g of ammonium persulfate was added to the solution. An aqueous solution dissolved in 10 mQ of ionized water was added, the interior space of the autoclave was sufficiently replaced with nitrogen gas, the autoclave was sufficiently cooled, and vinylidene fluoride/tetrofluoroethylene/bar-fluoromethyl perfluorovinyl ether (molar ratio 72
/18/10) mixed gas and perfluoro(1-(2
When 8.2 g of -iodoethyl)-4-(2-promoethyl)benzene was charged and the internal temperature was raised to 80°C while stirring, the internal pressure became 46 kg/a#G.

As the reaction progresses, the pressure decreases, and after 24 hours, the internal pressure reaches 4
When the concentration decreased to kg/dG, the autoclave was cooled, residual gas was released, and the polymerization reaction was stopped. A 18% aqueous sodium chloride solution was added to the resulting aqueous emulsion to coagulate the polymer, which was then washed with water and dried to obtain 325 g of a rubbery polymer.

Comparative Example 2 In Example 6, 6.4 g of bromotrifluoroethylene was used instead of perfluoro(1-(2-iodoethyl)-4-(2-bromoethyl)benzene), and 29
5 g of rubbery polymer was obtained.

Comparative Example 3 In Example 6, the molar ratio of the mixed gas was changed to 70/1.5/
15, 5.8 g of 1-bromo-2,2-difluoroethylene was used instead of perfluoro[1-(2-iodoethyl)-4-(2-bromoethyl)benzene], and 274 g of rubbery A polymer was obtained.

To 100 parts by weight of the fluorine-containing elastomer obtained in each of the above Examples and Comparative Examples, 20 parts by weight of MT carbon black and 1.5 parts by weight of 2,5-dimethyl-2°5-di(tert-butylperoxy)hexane were added. parts by weight, 3 parts by weight of lead oxide, and 4 parts by weight of triallyl isocyanurate were kneaded with a roll. All of the mixed wires had good processability such as kneading properties and flow characteristics.

After press-curing this mixture at 160°C for 10 minutes,
Vulcanized in an oven at 180℃ for 4 hours to form sheet and 0
A ring-shaped vulcanizate was obtained. However, Comparative Example 1 could not be vulcanized and only foamed.

For each vulcanizate, normal physical properties and other measurements were performed according to the following methods. The obtained results are based on the intrinsic viscosity of the fluorine-containing elastomer used, the comonomer composition molar ratio ("F-
(according to NMR), along with the iodine and bromine contents are shown in Table 1 below.

Normal physical properties: Heat aging resistance according to JIS K-6301: Measured as the rate of change in tensile strength after being exposed to a gear oven at 230°C for 70 hours Compression set P-240 ring with a wire diameter of 20
Measured on a product compressed by 25% for 70 hours at 0°C (blank below) Example 7 In Example 1, 1.6g of bromochloroiodomethane was used instead of 1-bromo-2-iodoperfluoroethane, and 475g of A rubbery polymer was obtained.

Example 8 In Example 1, 2.6 g of 3-oxa-1-iodo-2,5-dichloro-6-promperfluorohexane was used instead of 1-bromo-2-iodoperfluoroethane, and 499 g of rubber was used. A polymer was obtained.

The rubbery polymers obtained in Examples 7 and 8 were measured for halogen content, normal physical properties, heat aging resistance, and compression set. The results obtained are shown in Table 2 below.

(Left below) - Example 9 In an autoclave with an internal volume of 3Q, 1500 ml of deionized water was
+++Q and ammonium perfluorooctanoate 7
．． 5 g was charged, and the internal space was replaced with nitrogen gas. Next, a mixed gas of vinylidene fluoride/hexafluoropropene/tetrafluoroethylene (molar ratio 35/45/20) was introduced under pressure until the internal pressure reached 12 kg/aaG. Then 1-bromo-2-iodoperfluoroethane 4.4
g was pressurized and the internal temperature was raised to 50°C.

After separately pressurizing 3.5 g of ammonium persulfate, 0.4 g of ferrous sulfate heptahydrate, and 1.0 g of sodium sulfite as aqueous solutions dissolved in deionized water, Vinylidene fluoride/hexafluoropropene/tetrafluoroethylene (molar ratio 48/30/
2'2) A mixed gas was introduced under pressure until the internal pressure reached 16 kg/aJG to start the polymerization reaction. As the pressure decreases immediately with the start of the reaction, when the internal pressure drops to 15 kg/cdG, the pressure is re-pressurized to 16 kg/JG, and the polymerization reaction is continued in the same manner while maintaining the pressure of 15 to 16 kg/aJG. After a period of time, the unreacted mixed gas in the autoclave was purged to stop the reaction.

To the resulting aqueous emulsion was added an aqueous solution of 5 Mekali alum to coagulate the resulting polymer, which was then washed with water.

After drying, 433 g of rubbery polymer was obtained.

Example 10 In Example 9, the polymerization temperature was changed to 40° C., and the composition of the divided mixed gas was changed to a molar ratio of 46/35/19, respectively, to obtain 398 g of a rubbery polymer.

Example 11 In Example 9, the polymerization temperature was changed to 30° C., and the composition of the divided mixed gas was changed to a molar ratio of 44/39/17, respectively, to obtain 365 g of a rubbery polymer.

Example 12 In Example 11, the composition of the mixed gas added for 1 minute was changed to 40/38.
/22 molar ratio, and 373 g of rubbery polymer was obtained.

Example 13 In Example 9, 0.5 g of ascorbic acid and 0.2 g of sodium hydroxymethane sulfinate were used instead of ferrous sulfate heptahydrate and sodium sulfite,
418 g of rubbery polymer was obtained.

Example 14 In an autoclave with an internal volume of 3Q, 1500 g of deionized water was added.
II+ Q, ammonium perfluorooctanoate7.
5 g and 3.3 G of 1-bromo-2-iodoperfluoroethane, then vinylidene fluoride/hexafluoropropene/tetrafluoroethylene (mole ratio 39
/41/20) mixed gas at an internal pressure of 16 kg/dG (4
Press in until the temperature reaches 5℃). There, deionized water 901I
5.1 g of ammonium persulfate dissolved in Q and 0.51 g of acidic sodium sulfite helium were added to initiate the polymerization reaction.

The pressure decreases as the polymerization reaction progresses, so the internal pressure is 15
When the pressure decreased to 16 kg/a & G, the pressure was re-pressurized to 16 kg/aJG using a mixed gas with the above composition, and the reaction was continued for 9 hours, then the unreacted gas in the autoclave was injected to stop the reaction. To the obtained aqueous emulsion, an aqueous solution of brocade potash alum was added to coagulate the resulting polymer, which was then washed with water and dried to obtain 446 g of a rubbery polymer.

Example 15 In an autoclave with an internal volume of 3Q, 960 m of deionized water was added.
M, 1-buOmu2-iodoperf)Ltoxtan1
18g, ammonium perfluorooctanoate 4.2g
, disodium hydrogen phosphate dodecahydrate 4.2g, sodium hydroxide 0.075g, ammonium persulfate 4.8g
g and 0.3 g of acidic sodium sulfite were added thereto, and then 480 g of perfluoromethyl vinyl ether and 192 g of tetrafluoroethylene were charged.

After carrying out the copolymerization reaction at a reaction temperature of 50° C. for 24 hours, the reaction was stopped by purging the unreacted gas in the autoclave. To the obtained aqueous emulsion, a nishiki potash alum aqueous solution was added to coagulate the produced polymer.

Then, it was washed with water and dried to obtain 410 g of a rubbery polymer.

The rubbery polymers (fluorine-containing distomers) obtained in Examples 9 to 14 above were subjected to the same measurements as in the case of Clothing 1. In addition, regarding the rubbery polymer obtained in Example 15, fluorine-containing elastomer 100
Parts by weight, 15 parts by weight of carbon black, 0 parts by weight of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane
．． 76 parts by weight, 3 parts by weight of lead oxide, and 2 parts by weight of triallylisocyanurate at 180°C.
, press vulcanization for 10 minutes and oven vulcanization at 175° C. for 6 hours were performed, and similar measurements were performed on the obtained O-ring-shaped vulcanizate.

The results obtained are shown in Table 3 below.

(Left below) Example 16 In an autoclave with an internal volume of 3Q, 150f of deionized water was added.
lIIfl, ammonium perfluorooctanoate7.
5 g and 0.1-bromo-2-iodoperfluoroethane. :l1g, then vinylidene fluoride 1:V
l) F): 15k (70 mol%), tetrafluoroethylene [T1.[)80IX (10 mol%) and methyl perfluorovinyl ether (MFVE) 17h
(20 mo) Ii%”) tt bar 7 luo.

It was charged with 2.1 g of -1,5-hexadiene (0.1 mol % based on the monomer mixture) and heated to 50°C. There, 'J! The polymerization reaction was started by adding 3.8 g of ammonium sulfate and 38 g of trisium bisulfite dissolved in 20 m of deionized water. After 24 hours, unreacted gas was purged to terminate the reaction, and 5% potassium alum water was added to the resulting aqueous emulsion to coagulate the polymer, which was washed with water to yield 592 g of rubbery polymer. Obtained union.

Examples 17-20 In Example 1, the composition of the monomer mixture was changed as follows.

-j Vinylidene monofluoride 60 50 8
0 70 Tetrafluoroethylene 203
0 Methyl perfluorovinyl ether 20 20 2
0 20 perfluoro(methyl vinyl ether)
9 each in 10 or more Examples 16-20
The same measurements as in Table 1 above were performed on the rubber-like polymer (fluorine-containing elastomer) obtained with a polymerization rate of 0% or more. In addition, 150℃ No. 3 oil (JIS K
-6301No., 12 description) for 7 days, the hardness change, volume change rate, and TR-10 were also measured.

The results obtained are shown in Table 5 below, along with the iodine and bromine content in the fluorine-containing elastomer.

TR-10: Conforms to ASTM D-1329. This figure shows the degree of elongation recovery when the temperature is raised to a connector that has been given a certain amount of elongation and fixed at -80°C. Rubber with excellent low-temperature properties quickly recovers from fixed elongation deformation even at extremely low temperatures.

Taichi Ikkei

Claims (1)

[Claims] 1. General formula RBr_nI_m (where R is a fluorohydrocarbon group, a chlorofluorohydrocarbon group, a chlorohydrocarbon group, or a hydrocarbon group, and n and m are both 1 or 2) ) A method for producing a peroxide-curable fluorine-containing elastomer, which comprises homopolymerizing or copolymerizing a fluorine-containing olefin having 2 to 8 carbon atoms in the presence of an iodine-containing bromine compound represented by the following formula. 2. The method for producing a fluorine-containing elastomer according to claim 1, wherein the iodine-containing bromine compound is used in an amount of about 0.001 to 5% by weight of iodine and bromine combined in the fluorine-containing elastomer. 3. In the presence of a polymerization initiator, the polymerization reaction is approximately -30 to 15
A method for producing a fluorine-containing elastomer according to claim 1, which is carried out at a temperature of 0°C. 4. The method for producing a fluorine-containing elastomer according to claim 1, wherein the polymerization reaction is carried out at a temperature of about 0 to 50°C in the presence of a redox polymerization initiator. 5. The method for producing a fluorine-containing elastomer according to claim 1, which comprises copolymerizing a fluorine-containing olefin with an olefinic compound having 2 to 6 carbon atoms and/or a fluorinated diene having 4 to 8 carbon atoms.