JPH06345929A - Vulcanizable fluororubber composition - Google Patents

Abstract

(57) [Summary] [Structure] Fluorine rubber obtained by copolymerizing vinylidene fluoride, tetrafluoroethylene and propylene, organic onium compound, polyhydroxy compound, divalent metal oxide and / or divalent metal hydroxide A vulcanizable fluororubber composition comprising an amine, an imine or an organic phosphorus compound. [Effect] It is possible to obtain a fluororubber composition having remarkably improved vulcanizability in polyol vulcanization of fluororubber obtained by copolymerizing vinylidene fluoride, tetrafluoroethylene and propylene.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a vulcanizable fluororubber composition, and more particularly to a fluororubber composition having improved vulcanizability.

[0002]

2. Description of the Related Art A fluororubber obtained by copolymerizing vinylidene fluoride, tetrafluoroethylene and propylene is known as a material having particularly excellent engine oil resistance among fluororubbers. In the polyol vulcanization formulation used in combination with the vulcanization accelerator, the vulcanizability was poor as compared with the conventional fluororubber composed of vinylidene fluoride and hexafluoropropylene. Several methods are known as means for solving this problem (Japanese Patent Publication No. 1-15530, Japanese Patent Laid-Open No. 1-299860).

However, in JP-B-1-15530, in order to vulcanize the copolymer, it was necessary to introduce an unsaturated bond into the copolymer by treating it with an aqueous alkali solution. Further, in JP-A-1-299860, an organic onium compound excluding benzyltriphenylphosphonium chloride is said to be effective as a vulcanization accelerator, but as a very preferable composition,
It is described as containing one or more diorgano sulfur oxides for the purpose of increasing the cure rate of the composition. Furthermore, as seen in the examples, it is necessary to use diorgano sulfur oxides in order to obtain sufficient vulcanizability, except when some special phosphonium salts and iminium salts are used. It was

In Japanese Patent Publication No. 57-14703, it is known that the vulcanization reactivity of fluororubber is enhanced by using a nitrogen-containing organic compound and a third phosphine as a vulcanization accelerator. What is mainly used is a copolymer of vinylidene fluoride and another copolymerizable fluorine-containing olefin, and it is not effective when a fluororubber obtained by copolymerizing vinylidene fluoride, tetrafluoroethylene and propylene is used. It was insufficient.

Further, although a copolymer having a low vinylidene fluoride copolymerization ratio further improves the resistance to oxine oil, it has a poorer vulcanization reactivity, and a conventional method produces a molded article having a sufficient crosslinking density. It was difficult to get.

[0006]

DISCLOSURE OF THE INVENTION The present invention solves the problems of the prior art as described above, and provides a fluororubber composition comprising vinylidene fluoride, tetrafluoroethylene and propylene, which is excellent in vulcanizability. The purpose is to do.

[0007]

The present invention comprises (A) 100 parts by weight of a fluororubber obtained by copolymerizing vinylidene fluoride, tetrafluoroethylene and propylene,
(B) Organic onium compound 0.05 to 5 parts by weight,
(C) Polyhydroxy compound 0.5 to 10 parts by weight,
(D) Divalent metal oxide and / or divalent metal hydroxide 0.5 to 50 parts by weight, (E) at least one selected from amine, imine and organic phosphorus compound 0.01 to
5 parts by weight of a vulcanizable fluororubber composition.

The fluororubber obtained by copolymerizing vinylidene fluoride, tetrafluoroethylene, and propylene as the component (A) in the present invention is a monomer in the presence of a radical initiator, such as emulsion polymerization or suspension. Polymerization, solution polymerization,
It is obtained by copolymerizing by a conventionally known polymerization method of fluororubber such as bulk polymerization, and the copolymerization ratio is vinylidene fluoride, tetrafluoroethylene and propylene respectively from the characteristics of the obtained rubber, 2 to
It is preferably in the range of 70, 20 to 60, 20 to 50 mol%. Above all, a rubber excellent in engine oil resistance can be obtained particularly in a low range where the copolymerization ratio of vinylidene fluoride is less than 10 mol%.

The organic onium compound as the component (B) used in the present invention is an essential component for accelerating the polyol vulcanization of fluororubber, such as quaternary ammonium salt, quaternary phosphonium salt and quaternary iminium salt. Any conventionally known organic onium compound used for polyol vulcanization of fluororubber can be used.

Among them, the organic quaternary phosphonium salt, the organic quaternary ammonium hydrogen sulfate and the organic quaternary ammonium organic sulfonate are excellent in the vulcanization promoting effect. Among the phosphonium salts, tetraalkylphosphonium salts having the same or different hydrocarbon groups having 1 to 10 carbon atoms, and among the organic quaternary ammonium organic sulfonates, p
-Toluene sulfonate is particularly excellent in accelerating vulcanization, so that the copolymerization ratio of vinylidene fluoride as the component (A) is in a low range of less than 10 mol%, and fluorine having poor vulcanizability by the conventional method is used. The vulcanization reaction proceeds well even when rubber is used.

The amount of the component (B) used is 0.05 to 5 parts by weight, preferably 0.1 to 100 parts by weight of the component (A).
If the amount is less than this range, a sufficient vulcanization rate cannot be obtained, and if the amount is too much, the physical properties and heat resistance of the vulcanizate may deteriorate.

Specific examples of the component (B) include tetrabutylphosphonium chloride, tetrabutylphosphonium bromide, tributylmethoxypropylphosphonium chloride, trioctylmethylphosphonium chloride, trioctylbenzylphosphonium bromide, triphenylbenzylphosphonium chloride, tetrabutyl hydrogen sulfate. Ammonium, tetramethylammonium hydrogen sulfate, benzyltributylammonium hydrogen sulfate, trioctylmethylammonium hydrogen sulfate, 1,8-diazabicyclo [5.4.0] -7-undecenium hydrogen sulfate, 8-methyl-1,8-hydrogen sulfate. Diazabicyclo [5.4.0]-
7-Undecenium, p-toluenesulfonic acid 1,8-
Diazabicyclo [5.4.0] -7-undecenium,
Tetrabutylammonium p-toluenesulfonate, 8-benzyl-1,8-diazabicyclo [5.4.0] -7-undecenium trifluoromethanesulfonate, 8
-Benzyl-1,8-diazabicyclo [5.4.0]-
7-undecenium chloride, tetrabutylammonium chloride, tetrabutylammonium bromide, tetramethylammonium iodide, phenyltrimethylammonium bromide and the like can be mentioned, and these can be used alone or as a mixture of two or more kinds.

The component (C) polyhydroxy compound used in the present invention is a vulcanizing agent for fluororubber, and is a conventionally known polyhydroxy aromatic compound or fluoropolyhydroxy fat used as a vulcanizing agent for fluororubber. All group compounds can be used. Among them, as the component (C), 2,2-bis (4-hydroxyphenyl) propane [bisphenol A], 2,2-bis (4-hydroxyphenyl) perfluoropropane [bisphenol A
F] and hydroquinone are preferably used. These may be salts of alkali metals, alkaline earth metals, organic onium compounds and the like. These may be used alone or as a mixture of two or more.

The amount of the component (C) used is in the range of 0.5 to 10 parts by weight relative to 100 parts by weight of the component (A). If the amount is less than this, a vulcanized product having a sufficient crosslink density can be obtained. If it is difficult and too large, the crosslink density is too high and the vulcanizate may become brittle.

The divalent metal oxide and the divalent metal hydroxide of the component (D) used in the present invention are an acid acceptor and a vulcanization aid in the polyol vulcanization of fluororubber, All conventionally known metal oxides and metal hydroxides used for vulcanization of fluororubber can be used.

Specific examples of the component (D) include calcium hydroxide, magnesium hydroxide, calcium oxide, zinc oxide, lead oxide and magnesium oxide. Of these, a combination of calcium hydroxide and magnesium oxide is preferably used.

The amount of the component (D) used is 0.5 to 50 parts by weight, preferably 1 to 30 parts by weight, based on 100 parts by weight of the component (A).
The range is parts by weight.

The amine as the component (E) used in the present invention,
When the imine or organic phosphorus compound is used in combination with the above-mentioned component (B), vulcanization is further promoted, and the vulcanization acceleration effect is extremely large as compared with the conventionally used diorgano sulfur oxide.
The copolymerization ratio of vinylidene fluoride as the component (A) is 10
In the low range of less than mol%, the vulcanization reaction proceeds satisfactorily even when the conventional method uses a fluororubber having poor vulcanizability.

The amine or imine is the third one.
Amine and 1,8-diazabicyclo- [5.4.0] -7
-Undecene is preferably used because of its great effect of promoting vulcanization. As the organic phosphorus compound, phosphine,
Phosphite, phosphate, phosphine oxide, and phospholane are preferably used because of their large effect of promoting vulcanizability, and among them, the third phosphine is particularly preferably used.

When an organic phosphorus compound such as a tertiary phosphine is used as the component (E), an organic quaternary phosphonium salt, an organic quaternary ammonium hydrogensulfate or an organic quaternary ammonium organic sulfonate is used as the component (B). Is particularly effective.

Specific examples of the component (E) include 1,8-diazabicyclo [5.4.0] -7-undecene and 1,5-
Diazabicyclo [4.3.0] -5-nonene, triethylamine, tributylamine, diphenylamine, ethyleneimine, piperidine, morpholine, pyridine, benzotriazole, p-dimethylaminopyridine, 1,4
-Diazabicyclo [2.2.2] octane, triphenylphosphine, tributylphosphine, trioctylphosphine, triphenylphosphite, triethylphosphite, triphenylphosphate, tributylphosphate, triphenylphosphine oxide, trioctylphosphine oxide, etc. Can be mentioned. These may be used alone or as a mixture of two or more.

The amount of the component (E) used is 0.01 to 5 parts by weight, preferably 0.01 to 100 parts by weight of the component (A).
Is in the range of 3 parts by weight.

Further, in the fluororubber composition of the present invention, if necessary, other components such as carbon black,
Fillers such as silica, clay, diatomaceous earth and calcium carbonate, processing aids, lubricants, internal release agents, adhesion promoters, plasticizers, pigments, foaming agents and the like can be added. 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 in a rubber mixing device such as a roll, a kneader, a Banbury mixer, an extruder or the like. The fluororubber composition thus obtained is vulcanized and molded by a conventional method. That is, it is formed by compression molding, injection molding, extrusion molding, calender molding, or dipping by dissolving in a solvent, coating or the like.

Vulcanization conditions vary depending on the molding method and the shape of the molded product, but are generally at 100 ° C to 400 ° C for several seconds to 5 seconds.
It is a range of time. Secondary vulcanization may be performed to stabilize the physical properties of the vulcanizate. The secondary vulcanization conditions are 150 ° C. to 300 ° C. and 30 minutes to 48 hours.

[0026]

In the present invention, by using an organic onium compound and an amine, imine or organic phosphorus compound as a vulcanization accelerator, it is possible to reduce the amount of fluorinated rubber polymer from the main chain as compared with conventionally used vulcanization accelerators. Since the vulcanization acceleration effect in the addition reaction of dehydrofluorination and polyhydroxy compounds is extremely excellent, the vulcanizability in the polyol vulcanization of fluororubber obtained by copolymerizing vinylidene fluoride, tetrafluoroethylene and propylene is remarkably improved. It is thought to cause it.

[0027]

[Example] By the emulsion polymerization method, the copolymerization ratio of vinylidene fluoride / tetrafluoroethylene / propylene was 35 /
40/25 (molar ratio), Mooney viscosity ML1 + 4 (10
0 ° C.) = 70 fluororubber (fluororubber-1), and a fluororubber (fluororubber-2) having a copolymerization ratio of 6/52/42 (molar ratio) and a Mooney viscosity ML1 + 4 (100 ° C.) = 60 were synthesized. And used for the following tests.

According to the compositions shown in Tables 1 to 4, 2 parts of each component are used.
The mixture was uniformly mixed with a roll to obtain a fluororubber composition. The vulcanizability of the obtained composition was measured by ODR (Monsanto 2000 type).
It was measured by. In addition, each of the obtained compositions was 17
After press vulcanization at 7 ° C. for 20 minutes, secondary vulcanization was performed at 230 ° C. for 24 hours to obtain a vulcanized rubber. The physical properties of these vulcanized rubbers were measured according to JIS K6301. The results are shown in Tables 1 to 4. The abbreviations in the composition column in Tables 1 to 4 are as shown in Table 5.

[0029]

[Table 1]

[0030]

[Table 2]

[0031]

[Table 3]

[0032]

[Table 4]

[0033]

[Table 5]

[0034]

INDUSTRIAL APPLICABILITY The present invention remarkably improves the vulcanizability in a polyol vulcanization formulation of fluororubber composed of vinylidene fluoride, tetrafluoroethylene and propylene, which has excellent engine oil resistance, and is industrially applicable. It is also extremely economically useful. The fluororubber obtained by the present invention has excellent vulcanization physical properties such as heat resistance, engine oil resistance, and chemical resistance, and is based on crankshaft seals of automobile parts, O-rings around engines, gaskets, and sealing materials. It is useful in a wide range of applications such as heat exchanger gaskets, diaphragms, gaskets around radiators, tubes, etc., heat exchange gaskets of various plants such as food and chemicals, diaphragms, gaskets, and sealing materials.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Akiko Nakazawa 3 474 Tsukakoshi 2 Sachi-ku, Kawasaki City, Kanagawa Prefecture Asahi Glass Co., Ltd. Tamagawa Branch Office (72) Inventor Haruhisa Miyake 1150, Hazawa-machi, Kanagawa-ku, Yokohama Asahi Glass Central Research Institute Co., Ltd.

Claims (6)

[Claims] 1. A fluororubber obtained by copolymerizing (A) vinylidene fluoride, tetrafluoroethylene and propylene, 100 parts by weight, (B) an organic onium compound, 0.05 to 5 parts by weight, and (C) a polyhydroxy compound. 0.5 to 10 parts by weight, (D) divalent metal oxide and / or divalent metal hydroxide 0.5 to 50 parts by weight, (E) at least one selected from amine, imine and organic phosphorus compound 0 A vulcanizable fluororubber composition comprising 0.01 to 5 parts by weight. 2. The component (E) is a tertiary amine.
A vulcanizable fluororubber composition. 3. The vulcanizable fluororubber composition according to claim 1, wherein the component (E) is 1,8-diazabicyclo [5.4.0] -7-undecene. 4. The vulcanizable fluororubber composition according to claim 1, wherein the component (E) is a third phosphine. 5. The vulcanizable fluororubber composition according to claim 1, wherein the component (B) is an organic quaternary phosphonium salt. 6. The vulcanizable fluororubber composition according to claim 1, wherein the component (B) is at least one selected from organic quaternary ammonium hydrogensulfate and organic quaternary ammonium organic sulfonate.