JP2877975B2 - Fluorinated elastomer vulcanizing composition containing silicone rubber powder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel vulcanized composition of a fluorine-containing elastomer. More specifically, the present invention provides a fluorine-containing elastomer vulcanizate having excellent heat resistance and oil resistance while maintaining low-temperature impact brittleness resistance and amine-containing engine oil (SF class, SG class engine oil) resistance. The present invention relates to a fluorine-containing elastomer vulcanizing composition containing silicone rubber powder, which is improved from the above.

[0002]

2. Description of the Related Art Fluorine-containing elastomer vulcanizates have excellent heat resistance, oil resistance, etc., and are therefore used in various industrial fields such as automobiles, ships, aircraft, hydraulic equipment, general machinery, and pollution-related products. In departments, it is used for O-rings, gaskets, oil seals, diaphragms, hoses, rolls, sheet materials, and the like. However, the field of application is limited due to the disadvantage of breaking when subjected to impact at low temperatures and the problem of curing deterioration due to amine compounds added to improve the durability of engine oil accompanying the high performance of automobile engines. It had been. Accordingly, studies have been made to improve the cold resistance of the vulcanized fluorine-containing elastomer and to improve the amine-resistant engine oil (SF class, SG class engine oil) resistance.

[0003] Specific examples of methods for improving cold resistance include:
It can be roughly classified into two methods: trials using fluorine-containing monomers for fluorine-containing elastomers and blending different kinds of rubbers with fluorine-containing elastomers. Attempts from fluorine-containing monomers include optimization of the monomer composition ratio and introduction of new monomers. However, the former has a small effect, and the latter uses a very special fluorine-containing monomer, so that the price of the product is significantly increased. On the other hand, many attempts have been made to blend fluorine-containing elastomers with different kinds of rubbers, but in each case, the heat resistance and oil resistance characteristic of the fluorine-containing elastomers are sacrificed, and these are not satisfactory.

[0004] In recent years, silicone rubber powders having heat resistance next to fluoroelastomer while having excellent low-temperature properties have been developed, and their compounding with fluoroelastomer has been studied (Japanese Patent Laid-Open No. 1-215847). And JP-A-2-47149 and JP-A-2-107655). However, even in this case, the improvement of the low-temperature properties is insufficient, and the mechanical strength of the vulcanized product is significantly reduced,
There has been no product capable of achieving the object of improving low-temperature impact brittleness resistance while maintaining the same performance as a conventional fluorine-containing elastomer vulcanizate.

Further, an amine-containing engine oil (S
(F-class, SG-grade engine oil) As a fluorine-containing elastomer having improved properties, (tetrafluoroethylene)-
(Propylene) copolymer, but has a drawback that cold resistance is significantly inferior, and a fluorine-containing elastomer vulcanizing composition which satisfies both cold resistance and amine-containing engine oil (SF class, SG class engine oil) simultaneously. There was no.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a vulcanizate having excellent heat resistance and oil resistance, as well as a vulcanizate of a conventional fluorine-containing elastomer, while maintaining low-temperature impact brittleness. Is greatly improved, and amine-resistant engine oil (S
An object of the present invention is to provide a silicone rubber powder-containing fluorine-containing elastomer vulcanizing composition having improved F-class and SG-class engine oil properties.

[0007]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a vulcanized composition comprising a specific silicone rubber powder and a fluoroelastomer which can be vulcanized with an organic peroxide is obtained. The inventors have found that the present invention is suitable for the purpose, and have completed the present invention based on this finding. That is, the present invention provides (a) a fluorine-containing elastomer copolymer which is composed of a vinylidene fluoride unit and at least one fluorine-containing monomer and contains iodine or bromine, and which can be vulcanized with an organic peroxide. It is intended to provide a silicone rubber powder-containing vulcanized elastomer vulcanizing composition comprising (b) an epoxy group-containing silicone rubber powder, (c) an organic peroxide, and (d) a co-crosslinking agent.

The fluorine-containing elastomer used as the component (a) in the silicone rubber powder-containing fluorine-containing elastomer vulcanizing composition of the present invention is preferably from 40 to 90.
Mol%, more preferably 45 to 85 mol% of vinylidene fluoride units and at least one fluorine-containing monomer, preferably 0.005 to 10% by weight, more preferably 0.05 to 5% by weight Of iodine, or preferably 0.1
It is essential that the composition contains 01 to 2% by weight, more preferably 0.05 to 1.5% by weight of bromine and can be vulcanized with an organic peroxide. Such a fluorine-containing elastomer is disclosed in JP-B-54-1585 and JP-B-63-41928.
And Japanese Patent Application Laid-Open No. Sho 60-221409.

The at least one fluorine-containing monomer unit includes, for example, hexafluoropropene, pentafluoropropene, tetrafluoroethylene, trifluoroethylene, chlorotrifluoroethylene, dichlorodifluoroethylene, bromotrifluoroethylene,
Bromo-3,3,4,4-tetrafluorobutene-1,
Examples include fluorinated vinyl ethers and fluorinated alkyl vinyl ethers.

Specific examples of the fluorine-containing elastomer of the component (a) include (vinylidene fluoride)-(hexafluoropropene) copolymer and (vinylidene fluoride)-
(Hexafluoropropene)-(tetrafluoroethylene) copolymer, (vinylidene fluoride)-(hexafluoropropene)-(tetrafluoroethylene)-(4-bromo-3,3,4,4-tetrafluorobutene- 1) Copolymer, (vinylidene fluoride)-(perfluoromethylvinyl ether)-(tetrafluoroethylene)-(4
-Bromo-3,3,4,4-tetrafluorobutene-
1) Copolymers and the like.

In vulcanization molding of these copolymers,
It is known that iodine or bromine in a polymer is released by an organic peroxide decomposed by heating to form a radical, which is crosslinked via a co-crosslinking agent. It is essential that the silicone rubber powder used as the component (b) contains an epoxy group. Silicone rubber powders containing no epoxy group do not improve the low-temperature impact embrittlement resistance of the present invention.

The epoxy group-containing silicone rubber powder is preferably a powder or a granular material having an average diameter of 100 μm or less. This is because when the average diameter is 100 μm or more, the mechanical strength of the vulcanized product is significantly reduced.
As a specific example, it has a spherical flat particle diameter of 5 μm and a true specific gravity of 0.9.
7, an epoxy group-containing silicone rubber powder having a bulk specific gravity of 0.19 and a water content of 0.5% or less (trade name, manufactured by Toray Dow Corning Silicone Toray Fil E-601).

The organic peroxide as the component (c) may be any one which generates a peroxide radical under vulcanization conditions, such as 1,1-bis (t-butylperoxy).
-3,5,5-trimethylcyclohexane, 2,5-dimethylhexane-2,5-dihydroxy peroxide,
Di-t-butyl peroxide, t-butyl cumyl peroxide, dicumyl peroxide, a, a'-bis (t-butyl
Butylperoxy) -p-diisopropylbenzene,
2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3, benzoyl peroxide, t-butylperoxide Oxybenzene, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, t-
Butyl peroxymaleic acid, t-butyl-oxyisopropyl carbonate, and the like.

The co-crosslinking agent of component (d) includes, for example, triallyl cyanurate, triallyl isocyanurate, triallyl isocyanurate, triacrylformal, triallyl trimellitate, N, N'-m-phenylenebismaleimide , Diallyl phthalate, tetraallyl terephthalamide, tris (diallylamine) -s
-Triazine, triallyl phosphite, N, N-diallylacrylamide and the like, and a particularly preferred co-crosslinking agent is triallyl isocyanurate.

The mixing ratio of each of the components in the silicone rubber powder-containing fluorine-containing elastomer vulcanizing composition of the present invention is preferably 10 to 60 parts by weight of component (b) based on 100 parts by weight of component (a). , More preferably 20 to 50 parts by weight, component (c) 0.1 to 5 parts by weight, more preferably 0.5 to 3 parts by weight, (d)
The component is preferably 0.1 to 10 parts by weight, more preferably 0.5 to 5 parts by weight.

When the amount of the component (b) of the present invention is less than 10 parts by weight, the low-temperature impact brittleness is not sufficiently improved, and when it is more than 60 parts by weight, the tensile strength of the vulcanized product is greatly reduced. If the amount of the component (c) is less than 0.1 part by weight, a sufficient curing speed cannot be obtained, and if the amount is more than 5 parts by weight, the physical properties of the vulcanizate deteriorate. If the amount of the component (d) is less than 0.1 part by weight, a uniform vulcanized product cannot be obtained.
If the amount is more than parts by weight, the normal physical properties of the vulcanized product will be reduced.

Further, in the fluorine-containing elastomer vulcanizing composition containing silicone rubber powder of the present invention, if necessary, other components such as carbon black, graphite, silica, clay, diatomaceous earth, talc, calcium carbonate, calcium fluoride , A filler such as barium sulfate, a sulfone compound, a higher fatty acid ester, a low molecular weight polyethylene, a silicone oil, a metal soap, a processing aid, a plasticizer, a coloring agent, etc. can be blended. Lead oxide, magnesium oxide, zinc oxide, calcium oxide, calcium hydroxide, hydrotalcite compounds and the like may be blended. In addition, one or two types of conventionally known vulcanizing agents and vulcanization accelerators may be blended within a range not departing from the gist of the present invention.

The silicone rubber powder-containing vulcanized elastomer vulcanized composition thus obtained is vulcanized according to a conventional method. As the vulcanization method, for example, a method of kneading with an open kneading roll or a closed kneading roll (Banbury mixer, pressurized kneader, etc.), placing the mixture in a mold, pressurizing, performing primary vulcanization, and then performing secondary vulcanization. Can be Generally, the conditions of the primary vulcanization include a temperature of 120 to 200 ° C., a time of 1 to 180 minutes, and a pressure of 20 to 150 kg / m ² ,
As the conditions for the secondary vulcanization, a range of a temperature of 120 to 250 ° C. and a time of 0 to 48 hours is employed. As another vulcanizing means, a method of vulcanizing after preforming such as injection or extrusion, or one or more of ketones such as methyl ethyl ketone and acetone, ethers such as ethyl ether and tetrahydrofuran, etc. Prepare a solution or dispersion to be used as a medium.
A method of coating and vulcanizing the surface of a sheet, a plate, a tube, a pipe, a tank, a large container, or another molded product may be used.

[0019]

Next, the present invention will be described in more detail by way of examples, which should not be construed as limiting the present invention. The Mooney viscosity was measured according to JIS K630.
0, the hardness of the vulcanized product was measured according to JIS-A, 100% tensile stress, tensile strength, elongation, hot air aging test, immersion test, and low temperature impact brittleness test according to JIS K6301.

[0020]

Example 1 A composition having a vinylidene fluoride unit of 65 mol%
100 parts by weight of a fluoroelastomer having a hexafluoropropene unit of 15 mol%, a tetrafluoroethylene unit of 20 mol%, an iodine content of 0.4 wt%, and an ML _{1 + 10} (100 ° C.) of 5 are wound around an open-type kneading roll. And 20 parts by weight of Trefil E-601. Then, 4 parts by weight of triallyl isocyanurate (trade name, manufactured by TAIC Nippon Kasei Co., Ltd.) and 1.5 parts by weight of [Perhexa 25B, trade name, manufactured by Nippon Oil & Fats Co., Ltd.] were kneaded, and then allowed to stand overnight. Aged.

Then, after re-kneading, put in a mold,
Press vulcanization was performed at a temperature of 160 ° C. for 10 minutes to form a sheet. Next, the mold was taken out of the mold and heated in an air circulation furnace at a temperature of 180 ° C. for 4 hours to complete secondary vulcanization, and various tests were performed. Table 1 shows the physical properties of the vulcanized molded article thus obtained, the results of a hot air aging test (230 ° C for 24 hours), an amine-containing engine oil test (150 ° C for 168 hours), and a low-temperature impact embrittlement test. Shown in The amine-resistant engine oil test used TOYOTA Castle Motor Oil Clean SG 10W-30.

[0022]

Example 2 A vulcanized molded product was prepared and subjected to various tests in the same manner as in Example 1 except that the amount of Trefil E-601 was changed from 20 parts by weight to 40 parts by weight. Table 1 shows the results.

[0023]

Comparative Example 1 A vulcanized molded product was prepared and subjected to various tests in the same manner as in Example 1 except that trefil E-601 was not blended. Table 1 shows the results.

[0024]

Comparative Example 2 Example 1 was repeated except that 40 parts by weight of a methylsilicone rubber powder containing no epoxy group [Trefle E-600, trade name, manufactured by Dow Corning Silicone Toray Co., Ltd.] was used instead of Trefil E-601. A vulcanized molded product was prepared in the same manner as described above, and various tests were performed.
Table 1 shows the results.

Comparison between Examples 1 and 2 and Comparative Example 1 shows that the addition of the epoxy group-containing silicone rubber powder significantly improves the low-temperature impact embrittlement resistance and suppresses the curing deterioration due to the amine-containing engine oil. I have. On the other hand, the silicone rubber powder containing no epoxy group shown in Comparative Example 2 does not improve the low-temperature impact brittleness resistance, but also causes a drastic decrease in tensile strength.

[0026]

[Table 1]

[0027]

According to the present invention, the vulcanized product obtained from the silicone rubber powder-containing vulcanized elastomer-vulcanized composition of the present invention maintains excellent heat resistance and oil resistance as well as the conventional vulcanized elastomer-vulcanized product. At the same time, the resistance to low-temperature impact embrittlement is greatly improved, and the resistance to amine-containing engine oils (SF class, SG class engine oil) is improved. Accordingly, the silicone rubber powder-containing fluorinated elastomer vulcanizates of the present invention can be used in various industrial fields such as automobiles, ships, aircraft, hydraulic equipment, general machinery industries, pollution-related departments, etc., for O-rings, gaskets, oil seals, diaphragms, Not only can they be widely used as hoses, rolls, sheet materials, etc., but also in low-temperature areas where the use of fluoroelastomer vulcanizates has been restricted, and amine-containing engine oils (SF grade, SG grade engine oil) It can be used in an environment where it is in contact with water, and its industrial value is extremely high.

────────────────────────────────────────────────── (5) References JP-A-63-23907 (JP, A) JP-A-56-57811 (JP, A) JP-A-1-319512 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) C08L 27/10-27/16 C08L 83/04 C08G 59/20 C08L 63/00 C08F 8/00 C08F 14/16-14/22

Claims (1)

(57) [Claims] (A) a fluorine-containing elastomer copolymer comprising vinylidene fluoride units and at least one fluorine-containing monomer, containing iodine or bromine and vulcanizable with an organic peroxide; b) a fluorine-containing elastomer vulcanizing composition containing a silicone rubber powder, comprising a silicone rubber powder containing an epoxy group, (c) an organic peroxide, and (d) a co-crosslinking agent.