JP2511679B2 - Fluorine-containing elastomer composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a fluorine-containing elastomer composition. More specifically, it relates to a fluorine-containing elastomer composition capable of giving a vulcanized product having excellent vulcanized physical properties, particularly compression set.

[Conventional technology]

The fluorinated elastomer vulcanizate has useful properties in terms of heat resistance at high temperatures, chemical resistance, oil resistance, weather resistance, etc. Therefore, it is used for sealing materials such as gaskets, 0-rings and packings, hoses and sheets. In the fields of automobile industry, hydraulic industry, general machinery industry, aircraft industry, etc.
Demand is increasing rapidly. In other words, in addition to the demand for efficiency in the molding process, various demands for fluoroelastomer vulcanizates have diversified.
It can also be said that it has become stricter.

Vulcanization of fluorine-containing elastomers was first carried out using polyamine derivatives such as hexamethylenediamine carbamate and methylenebis (cyclohexyl) amine carbamate, but these vulcanization systems have scorch resistance (processing safety, It had the disadvantages of poor storage stability) and compression set of the vulcanizate. After that, as a vulcanization system capable of improving these drawbacks, a method of cross-linking with a polyhydroxy aromatic compound in the presence of a vulcanization accelerator and an acid acceptor has been proposed and put into practical use.

As a vulcanization accelerator in this vulcanization system, a quaternary phosphonium salt compound (JP-A-47-191), a quaternary ammonium salt compound (JP-B-52-38072, JP-A-47-3831)
Gazette), 8-alkyl (or aralkyl) -1,8-
The fourth of diazabicyclo [5,4,0] -undec-7-ene
Ammonium salt compound (JP-B-52-8863, JP-A-4)
No. 8-55231) or a fluorine-containing elastomer substantially not vulcanized with 1,8-diazabicyclo [5,4,0]
-A combination with Undec-7-ene (Japanese Patent Publication No. 57-20333) is used.

However, even when using these vulcanization systems,
The compression set of the vulcanizate is not yet at a sufficiently satisfactory level.

[Problems to be solved by the invention]

As a result of various investigations for the fluorine-containing elastomer composition improved in terms of compression set of the vulcanized product, the inventors have found that a specific quaternary ammonium salt complex compound is used as one component of the composition. It was found that this problem can be effectively solved.

[Means for Solving the Problem] and [Action] Therefore, the present invention relates to a fluorine-containing elastomer composition, which comprises (a) a fluorine-containing elastomer and (b) a divalent metal oxidation. And / or hydroxide, (c) polyhydroxy aromatic compound, and (d) [I] -of each compound represented by the following general formula.
[II] complex compound or [I]-[III] complex compound (R) aM (X) b [II] (R) cPO (X) d [III] (where n is 5 or 3, M is aluminum,
Tetravalent tin, trivalent iron, phosphorus or silicon, R is an alkyl group or an aryl group, X is chlorine, bromine or iodine, and a is 0 to 4, b is 1 to 5 and c is 0 to
2, d is 1 to 3).

The fluorine-containing elastomer to be vulcanized is a highly fluorinated elastic copolymer, and for example, a copolymer of vinylidene fluoride and another fluorine-containing olefin can be used. Specifically, for example, vinylidene fluoride and hexafluoropropene, pentafluoropropene,
Trifluoroethylene, trifluorochloroethylene,
Examples thereof include one or more copolymers of tetrafluoroethylene, vinyl fluoride, perfluoroacrylic acid ester, perfluoroalkyl acrylate, perfluoromethyl vinyl ether, perfluoropropyl vinyl ether, and the like, preferably vinylidene fluoride. -Hexafluoropropene terpolymer and vinylidene fluoride-tetrafluoroethylene-hexafluoropropene terpolymer.

Divalent metal oxides and hydroxides used as acid acceptors include magnesium, calcium, barium,
The proportion of one or more oxides or hydroxides of divalent metals such as lead and zinc is generally about 1 to 40 parts by weight, preferably about 3 to 15 parts by weight, per 100 parts by weight of the fluorine-containing elastomer. Used in.

Examples of the polyhydroxy aromatic compound as a cross-linking agent include 2,2-bis (4-hydroxyphenyl) propane [bisphenol A], 2,2-bis (4-hydroxyphenyl) perfluoropropane [bisphenol AF],
Hydroquinone, catechol, resorcin, 4,4'-dihydroxydiphenyl, 4,4'-dihydroxydiphenylmethane, 4,4'-dihydroxydiphenylsulfone, 2,2
-Bis (4-hydroxyphenyl) butane, and the like, preferably bisphenol A, bisphenol AF,
Hydroquinone or the like is used. They may also be in the form of alkali metal salts or alkaline earth metal salts. These cross-linking agents are fluorine-containing elastomer 100
It is used in a proportion of about 0.5 to 10 parts by weight, preferably about 0.5 to 6 parts by weight, per part by weight. If the amount used is less than this range, the crosslink density will be insufficient, while if it is more than this range, the crosslink density will become too high and the rubbery elasticity will tend to be lost.

In the general formula [I], the compound of n = 5 is 1,8-
The compound of diazabicyclo [5,4,0] -undec-7-ene and n = 3 is 1,5-diazabicyclo [4,3,
0] -non-5-ene.

Examples of the compound represented by the general formula [II] include aluminum trichloride, aluminum tribromide, methylaluminum dichloride, dimethylaluminum chloride, trimethyltin bromide, dimethyltin dichloride, diphenyltin dibromide, methyltin trichloride, ferric chloride. ,
Phosphorus trichloride, phosphorus tribromide, phenylphosphine dichloride, chlordiphenylphosphine, trimethylsilane bromide, trimethylsilane iodide, trimethylchlorosilane, dimethyldichlorosilane, triphenylchlorosilane, diphenyldichlorosilane, and the like. Examples of the compound represented by the general formula [III] include phosphorus oxychloride, methyl dichlorophosphate, methylphosphonic dichloride, phenylphosphonic acid dichloride, β
-Chlorethylphosphonic acid dichloride, bis (dimethylamino) phosphoryl chloride and the like.

The compound [I] and the compound [II] or [III] are used by heating the former in the presence or absence of a solvent such as acetone, ethanol, or toluene, using the former with a molar ratio of 1 or more for the latter. Reacts easily to form crystalline complex compounds.

One or more of these complex compounds are used in a proportion of about 0.05 to 5 parts by weight, preferably about 0.05 to 2 parts by weight, based on 100 parts by weight of the fluoroelastomer. If the proportion used is less than this range, the crosslinkability will be poor, and if it is greater than this range, various properties of the vulcanizate will be significantly adversely affected.

The vulcanized components may be blended as they are and kneaded, or carbon black, silica, clay, talc,
It may be diluted and dispersed with diatomaceous earth, barium sulfate or the like, or may be used as a masterbatch dispersion with a fluorine-containing elastomer. Incidentally, in the composition of the present invention, in addition to the above-mentioned compounding, conventionally known fillers, reinforcing agents, plasticizers, lubricants,
Processing aids, pigments and the like can be appropriately added to the composition.

The vulcanization is generally carried out by mixing the fluorinated elastomer with each of these vulcanized components and the various additives as described above by a commonly used mixing method such as roll mixing, kneader mixing, Banbury mixing, and solution mixing. Done by. Generally, primary vulcanization is about 140-200
About 2-120 minutes at a temperature of ℃, about 150-second secondary vulcanization
It is performed by heating at a temperature of 250 ° C. for about 0 to 30 hours.

[Effects of the Invention] The fluorine-containing elastomer composition according to the present invention has achieved excellent improvements in vulcanized physical properties, particularly compression set.

Further, the quaternary ammonium salt of the compound represented by the above general formula [I] has a large hygroscopicity and tide hygroscopicity, and it is necessary to handle the quaternary ammonium salt with sufficient care. The degree of can be significantly reduced.

〔Example〕

Next, the present invention will be described with reference to examples. In addition, the synthetic example of a complex compound is described as a reference example.

Reference Examples 1 to 9 1,8-diazabicyclo [5,4,0] -undec-7-ene (DBU) 10 g (66 mmol) or 1,5-diazabicyclo [4,3,0] -non-5-ene (DBN) 10 g (80 mmol)
Then, a predetermined amount of the compounds [II] and [III] was refluxed in 40 g of acetone for a predetermined time to obtain crystals as a complex compound.

Examples 1-9, Comparative Examples 1-2 Using acetone as a chain transfer agent in an aqueous medium,
A copolymer obtained by copolymerizing vinylidene fluoride and hexafluoropropene in the presence of ammonium persulfate as a polymerization initiator [comonomer component molar ratio 78:22, solution viscosity ηs
p / c 0.98 (35 ° C, in acetone, c = 1.0), Polymer Mooney viscosity ML _{1 + 10} 53 (121 ° C); Fluorine-containing elastomer A]
For the above, the compound having the compounding recipe shown in the following Table 2 was kneaded with an 8-inch mixing roll to prepare a fluorine-containing elastomer composition. In addition, the compounding amounts are all parts by weight below.

Mooney viscosity and scorch time (the time required for the Mooney viscosity to reach the minimum value of +5, which is a measure of storage stability and processing safety of the dough) for each of the various fluorine-containing elastomer compositions obtained
Was measured at a measurement temperature of 121 ° C.

In addition, the composition was press vulcanized at 180 ° C. for 5 minutes, then 2
Secondary vulcanization was performed for 22 hours in an oven at 30 ° C., and various physical properties of each vulcanizate were measured according to JIS K-6301. The compression set was measured by vulcanizing the O-ring of P-24 under the same conditions and compressing it by 25%. The results of these measurements are shown in Table 3 below.

Examples 10 to 11 and Comparative Example 3 Vinylidene fluoride-tetrafluoroethylene-hexafluoropropene (molar ratio 56:24:20) terpolymer [polymer Mooney viscosity ML _{1 + 10} 85 (121 ° C); Regarding the fluoroelastomer B], the composition having the formulation shown in Table 4 below was kneaded with an 8-inch mixing roll to prepare a fluoroelastomer composition.

The obtained fluorine-containing elastomer composition was measured in the same manner as in Examples 1 to 9, and the results are also shown in Table 4.

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Claims (1)

(57) [Claims] 1. (a) 100 parts by weight of a fluorine-containing elastomer,
(B) Bivalent metal oxide and / or hydroxide 1 to
40 parts by weight, (c) polyhydroxy aromatic compound 0.5 to 10
Parts by weight and (d) 0.05 to 5 parts by weight of [I]-[II] complex compound or [I]-[III] complex compound of each compound represented by the following general formula (R) aM (X) b [II] (R) cPO (X) d [III] (where n is 5 or 3, M is aluminum,
Tetravalent tin, trivalent iron, phosphorus or silicon, R is an alkyl group or an aryl group, X is chlorine, bromine or iodine, and a is 0 to 4, b is 1 to 5 and c is 0 to
2, d is 1 to 3).