JP3440555B2 - Fluoro rubber composition - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a fluororubber composition. More specifically, it relates to a fluororubber composition having excellent vulcanization adhesion to a metal .

[0002]

2. Description of the Related Art A vulcanized product of fluororubber has excellent properties such as heat resistance, chemical resistance, oil resistance, and weather resistance. Therefore, it is used as a sealing material for gaskets, O-rings, oil seals, packings, etc. Widely used in such fields as automobile industry, hydraulic industry, general machinery industry and aircraft industry. Among these sealing materials, vulcanization adhesion of fluororubber and metal is required to manufacture oil seals, etc. Generally, a silane coupling agent or the like is applied and baked on a phosphate-treated mild steel plate. However, the unvulcanized fluororubber compound is vulcanized under pressure.

Regarding the improvement of vulcanization adhesion of fluororubber to metal, JP-A-3-37251 discloses a vinylidene fluoride-tetrafluoroethylene-hydrocarbon olefin terpolymer copolymer gum, polyhydroxy compound, organic compound. Fluorinated elastomeric compositions comprising an onium compound and a fluorinated substituted aliphatic sulfonyl compound adhesion promoter are described. Here, as the fluorinated substituted aliphatic sulfonyl compound adhesion promoter, polyfluoroalkyl-N-substituted sulfonamide represented by the general formula RfSO ₂ NHR is used, but the N-substituent is exclusively N- Directed to alkyl groups.

However, in the vinylidene fluoride-hexafluoropropene type copolymer, polyfluoroalkyl is used as an adhesion promoter for adhering it to a metal.
When using -N-alkylsulfonamide,
If sufficient adhesion is not obtained and the amount of the adhesion promoter used is increased in order to increase the adhesion, the elongation value will decrease significantly, and the elongation characteristics of the rubber may not be sufficiently secured. Do you get it.

[0005]

The object of the present invention is to provide a fluororubber composed of vinylidene fluoride-hexafluoropropene copolymer or vinylidene fluoride-hexafluoropropene-tetrafluoroethylene terpolymer in which they are An object of the present invention is to provide a fluororubber composition having improved adhesiveness to a metal without substantially deteriorating the elongation property of the rubber originally possessed.

[0006]

The object of the present invention is as follows.
The fluorine rubber 100 parts by weight per formula RfSO ₂ NHR (wherein
Rf is a perfluoroalkyl group having 4 to 12 carbon atoms, and R is a phenyl group, a benzyl group or a phenethyl group.) A fluororubber containing 0.05 to 0.5 part by weight of a perfluoroalkyl -N-substituted sulfonamide represented by Achieved by the composition.

The fluororubber to be adhered to a metal or the like is a vinylidene fluoride-hexafluoropropene copolymer or hexafluoro in which hexafluoropropene is copolymerized in an amount of about 10 to 30 mol%, preferably about 15 to 25 mol%. About 5 to 25 mol% propene, preferably about 15 to 30 mol% and about 0.1 to 35 mol% tetrafluoroethylene, preferably about
A vinylidene fluoride-hexafluoropropene-tetrafluoroethylene terpolymer copolymerized with 5 to 25 mol% is used.

The former is capable of amine vulcanization and polyol vulcanization, and the latter is capable of peroxide vulcanization in the presence of a co-crosslinking agent. All of these vulcanization methods are known and used. A cross-linking agent corresponding to the vulcanization method is used. That is, as a crosslinking agent for amine vulcanization, 4,
4'-methylenebis (cyclohexylamine) carbamate, hexamethylenediaminecarbamate , N, N '
-Dicinnamylidene-1,6-hexanediamine and the like are used, and as the crosslinking agent for polyol vulcanization, 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,
A polyhydroxy aromatic compound such as 2-bis (4-hydroxyphenyl) butane or an alkali metal salt or alkaline earth metal salt thereof is used, and these crosslinking agents are about 0.5 to 10 per 100 parts by weight of the fluororubber. It is used in a proportion of about 1 to 5 parts by weight, preferably about 1 to 5 parts by weight. Further, as the co-crosslinking agent for peroxide vulcanization and the organic peroxide, any commonly used one can be used. The co-crosslinking agent is used in a ratio of about 0.5 to 10 parts by weight, preferably about 0.5 to 6 parts by weight, and the organic peroxide is about 0.1 to 100 parts by weight of the fluororubber. To 5 parts by weight, preferably about 0.5 to 3 parts by weight, respectively.

As the vulcanization accelerator, when a polyhydroxy aromatic compound or a metal salt thereof is used as a crosslinking agent, various quaternary ammonium salts or quaternary phosphonium salts are added per 100 parts by weight of fluororubber. It is used in a proportion of about 0.1 to 10 parts by weight, preferably about 0.1 to 2 parts by weight. As the acid acceptor, various divalent metal oxides or hydroxides are used in a ratio of about 1 to 20 parts by weight, preferably about 3 to 15 parts by weight, per 100 parts by weight of the fluororubber.

The perfluoroalkyl -N-substituted sulfonamide as an adhesion promoter is used in an amount of 0.05 to 0.5 parts by weight, preferably 0.1 to 0.5 parts by weight, per 100 parts by weight of fluororubber. If it is used below this range, the adhesive strength aimed at by the present invention cannot be obtained between the metal and the like. On the other hand, if it is used above this range, the elongation value decreases significantly, which is not preferable.

The composition is prepared by appropriately adding at least one of carbon black, silica, graphite, clay, talc, diatomaceous earth, barium sulfate, titanium oxide and the like as a filler or a reinforcing agent and other necessary compounding agents. However, the kneading is performed by a general kneading means such as a mixing roll. At this time, bisphenol
The addition of a cross-linking agent such as AF is preferably performed at a later point in time. The prepared composition is vulcanized by bonding the fluororubber composition to a metal, preferably a metal which has been treated with a primer, and then generally press vulcanization (primary vulcanization) and oven vulcanization (secondary vulcanization). However, injection molding is also possible.

[0012]

Effects of the Invention vinylidene fluoride - to hexafluoropropene based fluorine rubber, perfluoroalkyl -N- an N- substituent is phenyl, benzyl or phenethyl group
The addition of substituted sulfonamide as an adhesion promoter, a vinylidene fluoride - tetrafluoroethylene - as compared with the case of adding a perfluoroalkyl -N- alkylsulfonamido a hydrocarbon olefin terpolymer elastomer gum, the same additives It has excellent vulcanization adhesion in proportion,
Therefore, it is possible to add in a smaller amount, and it is possible to effectively reduce the decrease in elongation.

[0013]

EXAMPLES The present invention will now be described with reference to examples.

Examples 1 to 3 100 parts by weight of fluororubber A Vinylidene fluoride-hexafluoropropene (molar ratio 78:22) copolymer MT carbon black 20 〃 lead oxide 15 〃 4,4'-methylenebis (cyclohexylamine) Carbamate 2 〃 Perfluorooctyl-N-phenylsulfonamide 0.1 〃 (Example 1) Perfluorooctyl-N-benzylsulfonamide 0.1 〃 (Example 2) Perfluorooctyl-N-phenethylsulfonamide 0.1 〃 (Example 3) ) Each of the above ingredients was kneaded with an 8-inch mixing roll, and the kneaded product was subjected to press vulcanization at 180 ° C. for 5 minutes and 23
Oven vulcanization was performed at 0 ° C. for 22 hours.

The vulcanizates obtained were measured for the following items. Vulcanization physical properties: JIS K-6301 compliant Compression set: P-24 O-rings were compressed at 25% for 200 hours at 200 ° C. Further, metal adhesion was measured by the following method. Metal adhesion: 20 of commercial adhesive (Japan Unicar product AP-133)
A primer consisting of a wt% methanol solution is applied onto a phosphate-coated mild steel sheet, allowed to air-dry at room temperature for 30 minutes, and then baked at 150 ° C for 10 minutes, whereupon the kneaded product is Was adhered and pressure-vulcanized at 180 ° C. for 5 minutes. The rubber portion of this metal-fluorine rubber adhesive was grasped with pliers and peeled off, and the area ratio of the rubber remaining on the metal surface was determined and used as a measure of the metal adhesiveness.

Examples 4 to 6 Fluorine rubber A 100 parts by weight MT carbon black 25 〃 calcium hydroxide 5 〃 magnesium oxide 3 〃 bisphenol AF 2 〃 benzyltriphenylphosphonium chloride 0.4 〃 perfluorooctyl-N-phenylsulfonamide 0.1 〃 (Example 4) Perfluorooctyl-N-benzylsulfonamide 0.1 〃 (Example 5) Perfluorooctyl-N-phenethylsulfonamide 0.1 〃 (Example 6) Using each of the above components, Examples 1 to 1 Kneading, vulcanization and measurement were carried out in the same manner as in No. 3.

Examples 7 to 9 100 parts by weight of fluororubber B Vinylidene fluoride-hexafluoropropene-tetrafluoroethylene (molar ratio 68:16:16) terpolymer MT carbon black 20 〃 lead oxide 5 〃 triallyl Isocyanurate (Nippon Kasei Product TAIC M-60) 5 〃 Organic peroxide (Nippon Oil and Fat Products Perhexa 25B-40) 2 〃 Perfluorooctyl-N-phenylsulfonamide 0.1 〃 (Example 7) Perfluorooctyl-N- Benzylsulfonamide 0.1 〃 (Example 8) Perfluorooctyl-N-phenethylsulfonamide 0.1 〃 (Example 9) Using each of the above components, kneading, vulcanization and measurement were performed in the same manner as in Examples 1 to 3. It was conducted.

The measurement results in each of the above examples are shown in Table 1 below. Table 1 Actual measurement items 1 2 3 4 5 6 7 8 9 9 Hardness (JIS A) 70 71 71 69 69 70 75 74 75 100% modulus (MPa) 4.1 4.0 4.0 5.2 5.3 5.2 6.6 6.3 6.4 Tensile strength ( MPa) 17.5 17.1 17.3 15.2 14.9 14.8 21.2 20.8 20.5 Elongation (%) 270 270 260 230 220 230 200 190 190 Compression set (%) 51 52 52 19 20 20 32 33 32 Remaining rubber area (%) 100 100 100 100 100 100 100 100 100

Comparative Examples 1 to 3 In Examples 1, 4 or 7, perfluorooctyl was used.
No -N-phenylsulfonamide was used. The measurement results are shown in Table 2 below. Table 2 Measurement items Comparative example 1 Comparative example 2 Comparative example 3 Hardness (JIS A) 70 69 74 100% Modulus (MPa) 3.6 4.9 6.3 Tensile strength (MPa) 16.2 14.1 20.3 Elongation (%) 280 230 220 Compression permanent Strain (%) 50 19 31 Remaining rubber area (%) 60 70 50

Examples 10 to 12 In Example 4, the compounding amount of perfluorooctyl-N-phenylsulfonamide was 0.05 parts by weight (Example 10),
It was changed to 3 parts by weight (Example 11) or 0.5 parts by weight (Example 12). The measurement results are shown in Table 3 below, along with Example 4 where 0.1 part by weight was used. Table 3 Measurement items Example 10 Example 4 Example 11 Example 12 Hardness (JIS A) 69 69 70 70 100% Modulus (MPa) 5.0 5.2 5.7 6.3 Tensile strength (MPa) 14.5 15.2 16.3 16.4 Elongation (% ) 230 230 220 200 Compression set (%) 19 19 20 20 Rubber remaining area (%) 90 100 100 100

Comparative Examples 4 to 7 In Example 10, Example 4, Example 11 or Example 12, instead of perfluorooctyl-N-phenylsulfonamide, the same amount of perfluorooctyl-N- was used.
Methyl sulfonamide was used. The measurement results are shown in Table 4 below. Table 4 Measurement items Comparative example 4 Comparative example 5 Comparative example 6 Comparative example 7 Hardness (JIS A) 69 70 70 71 100% Modulus (MPa) 5.2 5.4 5.8 6.5 Tensile strength (MPa) 14.9 15.3 16.5 16.7 Elongation (% ) 200 200 180 170 Compression set (%) 19 20 20 20 Remaining rubber area (%) 70 80 100 100

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 60-215042 (JP, A) JP 3-37251 (JP, A) JP 52-56147 (JP, A) JP 48- 18936 (JP, B1) Special table H6-506004 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08L 27/12-27/20 C09J 127/12-127/20

Claims (2)

(57) [Claims] 1. A general formula RfSO ₂ NHR per 100 parts by weight of a fluororubber consisting of vinylidene fluoride-hexafluoropropene copolymer or vinylidene fluoride-hexafluoropropene-tetrafluoroethylene terpolymer (where: Rf
Is a perfluoroalkyl group having 4 to 12 carbon atoms, R is a phenyl group, a benzyl group or a phenethyl group) 0.05 to 0.5 parts by weight of a perfluoroalkyl -N-substituted sulfonamide represented by , For vulcanization adhesion to metal
A fluororubber composition used. 2. A fluororubber composition according to claim 1 which is a metal.
A metal-fluorine rubber adhesive obtained by vulcanizing and adhering to.