JP3435774B2 - Fluoro rubber composition - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluororubber composition for organic peroxide vulcanization. [0002] In the vulcanization of a fluororubber with an organic peroxide, unsaturated polyfunctional compounds such as triallylisocyanurate, hydroxides of divalent metals such as calcium hydroxide,
And a method using an organic onium salt such as a salt derived from 1,8-diazabicyclo [5.4.0] undecene-7 include a fluorine rubber obtained by copolymerizing an expensive monomer having iodine or bromine, and an onium salt. It is known as a method of easily and inexpensively vulcanizing a fluororubber as compared with a method using a fluororubber which has been subjected to an alkali treatment in the presence of a compound [JP-A-1-198654]. [0003] The method of blending the above-mentioned unsaturated polyfunctional compound, divalent metal hydroxide, organic onium salt and the like with fluororubber is a method for organic peroxide vulcanization. It is an excellent method that does not require a fluororubber having a special vulcanization site, but the storage stability is such that the vulcanization of the fluororubber compound gradually proceeds at room temperature during storage before vulcanization. There was a problem. DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and comprises (A) vinylidene fluoride and at least one copolymerizable therewith except vinylidene fluoride. Fluororubber obtained by copolymerizing one kind of ethylenically unsaturated monomer, (B) organic peroxide, (C) 2
At least one selected from the group consisting of hydroxides of divalent metals and oxides of divalent metals, (D) an organic onium salt, and (E) phenol, cresol, p-methoxyphenol, 3-methyl-4-isopropyl Phenol,
It is intended to provide a fluororubber composition comprising at least one selected from the group consisting of 2,4,6-tributylphenol and allylphenol. [0005] The component (A) used in the present invention is a copolymer comprising vinylidene fluoride and at least one ethylenically unsaturated monomer excluding vinylidene fluoride copolymerizable therewith. Examples of the ethylenically unsaturated monomer include hexafluoropropylene, pentafluoropropylene, propylene, trifluoroethylene, tetrafluoroethylene, chlorotrifluoroethylene, ethylene, vinyl fluoride, perfluoro (methyl vinyl ether) and perfluoro (hexyl). Perfluoro (alkyl vinyl ether) s such as vinyl ether). The component (A) includes vinylidene fluoride
A tetrafluoroethylene-propylene-based copolymer, a vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene-based copolymer, and a vinylidene fluoride-hexafluoropropylene-based copolymer are preferably employed. Here, the content ratio of the vinylidene fluoride polymerized unit is appropriately selected depending on desired physical properties, the type of the ethylenically unsaturated monomer to be copolymerized, and the like. % Fluorine rubber is employed. A vinylidene fluoride-tetrafluoroethylene-propylene copolymer is preferable because a vulcanized fluoro rubber having excellent engine oil resistance can be obtained. In particular, a terpolymer containing 0.1 to 70 mol% of vinylidene fluoride polymer units, 20 to 60 mol% of tetrafluoroethylene polymer units and 10 to 50 mol% of propylene polymer units is added. Vulcanization properties such as engine oil resistance of vulcanized fluororubber and vulcanization characteristics are well-balanced and excellent, so that it is preferably employed. Further, according to the composition of the present invention, a vulcanized product having good vulcanization characteristics and excellent physical properties can be obtained even if no easily vulcanizable site is introduced into the component (A). be able to. Here, the easily vulcanizable portion is bromine, iodine, a double bond, or the like introduced into the polymer chain. The easily vulcanizable portion can be introduced by, for example, a method of copolymerizing a monomer such as an iodine compound or a bromine compound, a heat treatment for imparting a double bond, or an alkali treatment in the presence of an onium salt. For the production of the component (A), various polymerization systems such as bulk polymerization, suspension polymerization, emulsion polymerization and solution polymerization can be employed. Further, a catalyst polymerization method using a free radical initiator, an ionizing radiation polymerization method, a redox polymerization method, or the like can be appropriately employed. The component (B) used in the present invention is an organic compound having an -OO- bond used as a vulcanizing agent, such as peroxyketal, dialkyl peroxide,
Diacyl peroxide, peroxyester, hydroperoxide and the like are employed. Specific examples thereof include benzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-bis (tert-butylperoxy) hexane, 2,5- Dimethyl-2,5-bis (tert-
Butylperoxy) hexyne-3, α, α'-bis (t
tert-butylperoxy) -p-diisopropylbenzene, 1,1-bis (tert-butylperoxy)-
3,3,5-trimethylcyclohexane and the like. Of these, α, α′-bis (tert-butylperoxy) -p-diisopropylbenzene, 2,5-
Dimethyl-2,5-bis (tert-butylperoxy) hexane can be preferably used. The amount of the component (B) used is preferably 0.5 to 10 parts by weight, particularly preferably 1 to 5 parts by weight per 100 parts by weight of the component (A). In the composition of the present invention, the vulcanization reaction is promoted by blending the components (C) and (D). The component (C) includes hydroxides or oxides of magnesium, calcium, lead, zinc and the like. The amount of component (C) used is preferably in the range of 1 to 20 parts by weight, particularly 2 to 10 parts by weight per 100 parts by weight of component (A). However, it can be used more than that. As the component (D), tetrabutylammonium bromide, tetrabutylammonium hydrogen sulfate,
Trioctylmethylammonium hydrogen sulfate, 8-benzyl-1,8-diazabicyclo [5.4.0] undeca-
7-enium chloride, p-toluenesulfonic acid 1,8
Organic onium compounds such as diazabicyclo [5.4.0] undec-7-enium, tetrabutylphosphonium chloride, tetrabutylphosphonium bromide, tributyl (methoxypropyl) phosphonium chloride, benzyltrioctylphosphonium chloride and benzyltriphenylphosphonium chloride; Is exemplified. These are used alone or as a mixture of two or more.
The amount of the component (D) to be used is generally 0.1 to 5 parts by weight, preferably 0.3 to 3 parts by weight, per 100 parts by weight of the component (A). If the amount is less than 0.1 parts by weight, sufficient vulcanization density and vulcanization properties cannot be obtained. If the amount exceeds 5 parts by weight, moldability is adversely affected due to scorch phenomenon and vulcanization such as chemical resistance. Deteriorate the properties of objects. The component (E) includes phenol, cresol,
p-methoxyphenol, 3-methyl-4-isopropylphenol, 2,4,6-tributylphenol and
At least selected from the group consisting of
It is one type and acts as a storage stabilizer of the fluororubber composition of the present invention at room temperature or as a vulcanization retarder during vulcanization. The amount of the component (E) used is 100 parts of the component (A).
It is usually in the range of 0.05 to 5 parts by weight based on parts by weight. The fluororubber composition of the present invention contains reinforcing agents such as carbon black, fine silica, clay and talc, triallyl isocyanurate, trimethylolpropane trimethacrylate, etc., which are conventionally used in the production of vulcanized rubber. Vulcanization aids, other fillers, pigments,
Add antioxidant, stabilizer, processing aid, internal release agent, etc.
You may mix. Further, other synthetic rubber, natural rubber, thermoplastic resin, thermosetting resin, or the like may be mixed. The fluororubber composition of the present invention can be easily obtained by mixing the above components with a usual rubber kneading device such as a roll, kneader, Banbury mixer, extruder or the like. The fluororubber composition of the present invention is vulcanized and molded by a usual method. Vulcanization conditions vary depending on the molding method and the shape of the molded product, but are generally from 100 ° C to 400 ° C.
For several seconds to 5 hours. Further, secondary vulcanization may be performed to stabilize the physical properties of the vulcanized product. Secondary vulcanization conditions are 150 ° C. to 300 ° C. for about 30 minutes to 48 hours. In the present invention, the organic peroxide of the component (B) is generated by decomposition of the organic onium salt of the component (D) and the hydroxide or oxide of the divalent metal of the component (C). a radical, it is presumed that the storage stability is improved by trapping with Ingredient (E). In the examples, "parts" means "parts by weight". Example 1 The copolymerization ratio of vinylidene fluoride / tetrafluoroethylene / propylene was 35/40/25 by an emulsion polymerization method.
(Molar ratio) of fluororubber was produced. This fluoro rubber 1
MT carbon 30 parts, Perhexa 2,5 for 00 parts
B (manufactured by NOF CORPORATION, organic peroxide 2,5-dimethyl-
1 part of 2,5-bis (tert-butylperoxy) hexane, 3 parts of magnesium oxide, 0.8 part of tetrabutylammonium hydrogen sulfate, and 0.2 part of p-methoxyphenol were uniformly mixed with 2 rolls. A fluoro rubber composition was obtained. The Mooney viscosity of this fluororubber composition was ML (1 + 4) 121 ° C = 58. Further, the Mooney viscosity ML (1 + 4) 121 ° C. after storing this fluororubber composition at 25 ° C. for 30 days was 60. This fluororubber composition was subjected to press vulcanization at 170 ° C. for 10 minutes and secondary vulcanization at 230 ° C. for 24 hours, and the physical properties were measured. The hardness (JIS-A) was 70 and the 100% modulus was 5. 5MPa, tensile strength 16.3MPa, elongation 2
30%. Reference Example 1 A fluororubber composition was obtained in exactly the same manner as in Example 1 except that 0.2 parts of Nowguard 445 (manufactured by Uniroyal Co., diphenylamine derivative) was used instead of p-methoxyphenol. . Mooney viscosity ML of this fluoro rubber composition
(1 + 4) 121 ° C. is 60, and 30 ° C. at 25 ° C.
Mooney viscosity ML (1 + 4) after storage for 1 day 121 ° C
Was 61. The fluororubber composition is heated at 170 ° C for 1
When the physical properties were measured by press vulcanization for 0 minute and secondary vulcanization at 230 ° C. for 24 hours, the hardness (JIS-A) was 7
2. 100% modulus is 6.1 MPa, tensile strength is 1
5.9 MPa, elongation was 220%. Example 2 A fluororubber having a copolymerization ratio of vinylidene fluoride / hexafluoropropylene of 80/20 (molar ratio) was produced by an emulsion polymerization method. MT to 100 parts of this fluoro rubber
30 parts of carbon, 1 part of perhexa 2,5B, 3 parts of magnesium oxide, tetrabutylammonium hydrogen sulfate 0.1 part
Eight parts and 0.2 part of 3-methyl-4-isopropylphenol were uniformly mixed with two rolls to obtain a fluororubber composition. Mooney viscosity ML of this fluoro rubber composition
(1 + 4) 121 ° C was 51. Further, the Mooney viscosity ML (1 + 4) 121 ° C. after storing this fluororubber composition at 25 ° C. for 30 days was 52. Press vulcanization of this fluororubber composition at 170 ° C. for 10 minutes and 2
When physical properties were measured by secondary vulcanization at 30 ° C. for 24 hours, the hardness (JIS-A) was 73, the 100% modulus was 5.9 MPa, the tensile strength was 15.4 MPa, and the elongation was 20.
It was 0%. Reference Example 2 The procedure was the same as in Example 2 except that 0.2 parts of Nocrack White (a paraphenylenediamine derivative manufactured by Ouchi Shinko Co., Ltd.) was used instead of 3-methyl-4-isopropylphenol. Thus, a fluororubber composition was obtained. The Mooney viscosity viscosity ML (1 + 4) 121 ° C. of this fluororubber composition was 50, and the Mooney viscosity viscosity ML (1 + 4) 121 ° C. after storage at 25 ° C. for 30 days was 52. This fluororubber composition was subjected to press vulcanization at 170 ° C. for 10 minutes and secondary vulcanization at 230 ° C. for 24 hours, and its physical properties were measured. 7MPa, tensile strength 14.6MPa, elongation 2
00%. Comparative Example 1 A fluororubber composition was obtained in exactly the same manner as in Example 1 except that p-methoxyphenol was not used. The Mooney viscosity ML (1 + 4) 121 ° C. of the fluororubber composition was 58. Further, the Mooney viscosity ML (1 + 4) 121 ° C. after storing this fluororubber composition at 25 ° C. for 30 days was 105. The fluororubber composition is heated at 170 ° C for 1
When the physical properties were measured by press vulcanization for 0 minutes and secondary vulcanization at 230 ° C. for 24 hours, the hardness (JIS-A) was 7
3, 100% modulus is 6.6 MPa, tensile strength is 1
6.9 MPa, elongation was 200%. The present invention provides a fluororubber composition which is inexpensive and can be easily vulcanized with an organic peroxide and has good storage stability, and has a great industrial advantage. Furthermore, based on various excellent vulcanization properties, a wide range of applications such as automotive radiators, O-rings around engines, gaskets, sealing materials, diaphragms, tubes, hoses, and similar parts in food plants and chemical plants. Is extremely useful in

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-306235 (JP, A) JP-A-4-209643 (JP, A) JP-A-1-2974761 (JP, A) JP-A-50- 104248 (JP, A) JP-A-1-135854 (JP, A) JP-A-64-40550 (JP, A) JP-A-1-198654 (JP, A) JP-A-5-279535 (JP, A) JP-A-3-128955 (JP, A) JP-A-49-16740 (JP, A) JP-A-6-107803 (JP, A) JP-A-9-504323 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08L 27/16

Claims (1)

(57) [Claim 1] (A) Obtained by copolymerizing vinylidene fluoride and at least one ethylenically unsaturated monomer copolymerizable therewith, excluding vinylidene fluoride. (B) an organic peroxide, (C) at least one selected from the group consisting of divalent metal hydroxides and divalent metal oxides, (D) an organic onium salt, and (E) Selected from the group consisting of phenol, cresol, p-methoxyphenol, 3-methyl-4-isopropylphenol, 2,4,6-tributylphenol and allylphenol
A fluororubber composition comprising at least one kind of fluororubber.