JPS5946986B2 - Fluorine-containing elastomer composition - Google Patents

Description

[Detailed description of the invention] The present invention relates to a fluorine-containing elastomer composition.

More specifically, the present invention relates to a fluorine-containing elastomer composition that provides a vulcanizate with excellent vulcanization properties, dough storage stability, and processing safety, and with greatly improved vulcanization physical properties. Fluorine-containing elastomer vulcanizates have useful properties such as heat resistance at high temperatures, chemical resistance, oil resistance, and weather resistance.
Sealing materials such as gaskets, O-rings, packing, etc.
Demand for hoses, sheets, etc. is rapidly increasing in fields such as the automobile industry, hydraulic industry, general machinery industry, and aircraft industry.

In other words, in addition to the demand for increased efficiency in the molding process, various requirements for fluorine-containing elastomer vulcanizates are diversifying and becoming more stringent. Vulcanization of fluorine-containing elastomers was initially carried out using polyamine derivatives such as hexamethylene diamine carbamate and methylene bis(cyclohexyl) amine carbamate, but these vulcanization systems had poor scorch resistance (processing safety). , storage stability) and compression set of the vulcanizate.

Subsequently, as a vulcanization system capable of improving these drawbacks, a method of crosslinking with a polyhydroxy aromatic compound in the presence of a vulcanization accelerator and an acid acceptor was proposed, and has now been put to practical use. As vulcanization accelerators in this vulcanization system, quaternary phosphonium compounds (Japanese Patent Application Laid-open No. 1986-191) and quaternary ammonium compounds (Japanese Patent Publication No. 52-38) are used.
072, JP-A-47-3831), quaternary ammonium compounds of 8-alkyl (or aralkyl)-1,8-diazabicyclo[5,4,0]-undeco Publication No.-8863, Japanese Patent Application Laid-open No. 1973
-55231) or 1,8-diazabicyclo in an amount that does not substantially vulcanize the fluorine-containing elastomer.
A combination with 5,4,0]-Undeku J Me[en (Japanese Unexamined Patent Publication No. 131239/1983) is used.

However, even when these vulcanization systems are used, the compression set of the vulcanizate is still not at a fully satisfactory level, especially at high temperatures, and there is also the drawback that the mechanical strength of the vulcanizate is low. It has not been resolved yet. As a vulcanization accelerator,
When a quaternary phosphonium compound is used, in addition to the above-mentioned drawbacks, its melting point is generally high, often over 200°C, resulting in poor dispersion in the compounded composition during kneading processing. In addition, in terms of shapeability during vulcanization molding, there are problems such as cracks, defects, and fine foaming, especially when manufacturing molded products with complex shapes. Although there are demands for various uses as described above, it is currently not possible to satisfy all of them.

On the other hand, in order to meet the demands for increased efficiency in the molding process, it is necessary to further increase the vulcanization rate, and this is generally achieved by increasing the amount of vulcanization accelerator; There is a problem in that the compression set of sulfur is adversely affected.

Therefore, a method of using a quaternary phosphonium compound or a quaternary ammonium compound and a triorganophosphorus oxide or a diorganosulfoxide together as a vulcanization accelerator component (Japanese Unexamined Patent Publication No. 50-67860), No. 4
A method of using a quaternary phosphonium compound in combination with β-diketones (Japanese Patent Publication No. 52-9221), a method of using a quaternary phosphonium compound in combination with dipyridyl, 2-hydroxypyridine, etc. (Japanese Patent Publication No. 52-9465), etc. However, none of these methods are satisfactory because they sacrifice scorch resistance and compression set of the vulcanizate.

Therefore, the present inventor conducted various studies in order to increase the vulcanization rate without deteriorating the scorch resistance and the compression set of the vulcanizate, and to solve the problems seen in the conventionally known vulcanization systems described above. As a result, in a vulcanization system using a polyhydroxy aromatic compound as a crosslinking agent in the presence of an acid acceptor, a specific quaternary ammonium compound and an N-alkyl-substituted amide compound are used together as a vulcanization accelerator component. Furthermore, 1,8-diazabicyclo[5,4
, 0] undecou J me[en, 1,5-diazabicyclo[
430] By adding non-5-ene or 4-dialkylaminopyridine having an alkyl group having 1 to 4 carbon atoms, storage stability, processing safety, and vulcanization properties (vulcanization fluidity, vulcanization Not only is it excellent in terms of speed, etc.), it can also significantly improve both the mechanical strength and compression set of the vulcanizate, which were problems that should be improved in the known vulcanization systems. We have discovered a vulcanization system that is effective in improving dispersibility during kneading and shaping properties during vulcanization molding, and have now completed the present invention.

The present inventor has previously discovered that a specific
grade ammonium compound and an amount of 1,8-diazabicyclo[5,4,0
] Undecou J Me[en, 1,5-diazabicyclo[4
, 3,0] non-5-ene or 4-dialkylaminopyridine having an alkyl group having 1 to 4 carbon atoms.
No. 6 (Japanese Unexamined Patent Publication No. 56-161448)), by further adding an N-alkyl substituted amide compound to this system, the dough has excellent storage stability, processing safety, and vulcanization properties, and is easy to mold and process. Not only has the prior knowledge shown that it is possible to significantly improve the shapeability, mechanical strength and compression set of the vulcanizate, but also that the vulcanization rate can be further increased without sacrificing scorch resistance. This effect was obtained.

Therefore, the present invention relates to a fluorine-containing elastomer composition,
This composition comprises (a) a fluorine-containing elastomer, (b) an oxide and/or hydroxide of a divalent metal, (c) a polyhydroxy aromatic compound, (d) a general formula or (here,
R is hydrogen or a dialkylamino group having an alkyl group having 1 to 4 carbon atoms, R is an aralkyl group having 7 to 20 carbon atoms, and R2 and R3 are each a dialkylamino group having 1 to 2 carbon atoms.
R4 is an alkyl group having 1 to 24 carbon atoms or an aralkyl group having 7 to 2.0 carbon atoms,
R' is an amino group or a group represented by -R5-0Y, where R is an alkylene group having 1 to 8 carbon atoms,
Y is hydrogen, an alkyl group having 1 to 24 carbon atoms, or -COR
6, where present is an alkyl group or aryl group having 1 to 24 carbon atoms, Z is oxygen or a methylene group, and X is a halide, hydroxylate, alkoxylate, carboxylate, phenoxide , sulfonate, sulfate, sulfite, carbonate or nitrate) and (e) an N-alkyl substituted amide compound;
f) 1,8-diazabicyclo[5,4,O]undec-
7-ene, 1,5-diazabicyclo[4,3,0]non-5-ene or 4 having an alkyl group having 1 to 4 carbon atoms
It additionally contains dialkylaminopyridine.

Examples of N-alkyl substituted amide compounds include N-alkyl substituted carboxylic acid amides such as dimethylformamide and dimethylacetamide, N-alkyl substituted heterocyclic amides such as N-methyl 2-pyrrolidone, and N-alkyl substituted heterocyclic amides such as hexamethylphosphoramide. Alkyl-substituted phosphoric acid amides and the like are used.

These N-alkyl-substituted amide compounds are used in an amount of about 0.1 to 5 parts by weight per 100 parts by weight of the fluorine-containing elastomer, and preferably about 3 parts by weight or less. If it is used in a ratio higher than this, the vulcanization rate will be significantly faster, but it will also have a negative effect on the scorch resistance (storage stability, processing safety) of the fabric, the heat aging resistance and compression set of the vulcanizate. Become. On the other hand, if the amount is less than this, the desired effect cannot be achieved. By blending the N-alkyl-substituted amide compound in such a ratio, the crosslinking reaction is significantly promoted, the formability during vulcanization molding is improved, and the degree of crosslinking is high, resulting in improved mechanical strength. The effect of obtaining a vulcanizate can be achieved.

The other components of the composition are the same as conventional ones.

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, hexafluoropropene, pentafluoropropene, trifluoroethylene, trifluorochloroethylene, tetrafluoroethylene, vinyl fluoride, perfluoroacrylate, perfluoroalkyl acrylate, perfluoromethyl One or more copolymers such as vinyl ether and perfluoropropyl vinyl ether,
Preferred examples include vinylidene fluoride-hexafluoropropene binary copolymer and vinylidene fluoride-tetrafluoroethylene-hexafluoropropene ternary copolymer. Divalent metal oxides used as acid acceptors,
As the hydroxide, one or more types of oxides and hydroxides of divalent metals such as magnesium, calcium, barium, lead, and zinc are generally used in an amount of about 1 to 40% per 100 parts by weight of the fluorine-containing elastomer. Parts by weight are used, preferably about 3 to 15 parts by weight.

Examples of the polyhydroxy aromatic compound as a crosslinking agent include 2,2-bis(4-hydroxyphenyl)propane [bisphenol A], 2,2-bis(4-hydroxyphenyl)perfluoropropane [bisphenol Ichiru AF
], hydroquinone, catechol, resorcinol, 4,4/
-dihydroxydiphenyl, 4,4'-dihydroxyphenylmethane, 4,4'-dihydroxyphenyl sulfone, 2,2-bis(4-hydroxyphenyl)butane, etc., preferably bisphenol A, Bisphenol AF, hydroquinone, etc. are used. They may also be in the form of alkali metal or alkaline earth metal salts. These crosslinking agents are used in an amount of about 0.5 to 10 parts by weight, preferably about 0.5 to 6 parts by weight, per 100 parts by weight of the fluorine-containing elastomer. If the usage ratio is less than this, the crosslinking density will be insufficient, while if it is more than this, the crosslinking density will become too high and there will be a tendency to lose rubber-like elasticity. Examples of the quaternary ammonium compound represented by the above formula [1] include 1-benzylpyridinium chloride, 1-phenethylpyridinium chloride, 1-benzylpyridinium chloride, 1-benzylpyridinium stearate, 1-benzyl-4-dimethylaminopyridinium chloride, 1-benzyl-4
-dimethylaminopyridinium bromide, 1-benzyl-4-dimethylaminopyridinium methylsulfate, and the like.

Examples of the quaternary ammonium compound represented by the formula [■] include trimethylhydrazinium chloride, trimethylhydrazinium bromide, dimethylbutylhydrazinium chloride, dimethyl-dodecylhydrazinium chloride, and dimethylhexadecylhydrazinium. Chloride, dimethylbenzylhydrazinium chloride, dimethylpenzylhydrazinium sulfide, trimethylhydrazinium carbonate, (2-hydroxyethyl)trimethylammonium hydroxide, (2-hydroxyethyl)trimethylammonium chloride, choline chloride, cholinebromide, acetylcholine chloride ,
Examples include acetylcholinebromide and benzoylcholine chloride. Examples of the quaternary ammonium compound represented by the formula [] include 1,1-dimethylpiperidinium chloride, 1-methyl-1-benzylpiperidinium chloride, 1,1-dimethylmorporinium chloride,
1,1-dimethylmorporinium chloride, 1-methyl-1-pencylmorporinium chloride, 1-methyl-
Examples include 1-pencyl molporinium naterate. Further, as the quaternary ammonium compound represented by the above [M formula], 1-butyl-1,4-diazabicyclo[2,2,2]octanium chloride, 1-benzyl-1,4-diazabicyclo[2, 2,2] octanium chloride and the like.

One or more of these quaternary ammonium compounds are present in an amount of about 0.1 per 100 parts by weight of the fluorine-containing elastomer.
It is used in a proportion of ~10 parts by weight, preferably about 0.1-2 parts by weight.

If the proportion used is less than this, the crosslinking properties will be poor, and if the proportion is greater than this, the properties of the vulcanizate will be significantly adversely affected. 1,8-diazabicyclo[5,4,0] undecou J me[ene or 1,5-diazabicyclo[4,3,
0] When non-5-ene is further blended, it shows a remarkable effect on improving the compression set of the vulcanizate, and also 4-dimethylaminopyridine and 4-dimethylaminopyridine having an alkyl group having 1 to 4 carbon atoms.
Even if 4-dialkylaminopyridine such as diethylaminopyridine or 4-di(n-butyl)aminopyridine is further blended, the effect of promoting crosslinking reaction is significant and the amount of quaternary ammonium compound blended can be reduced. As a result, compression set can be effectively improved.

These additional components may be added in such amounts that one or more of them will not substantially vulcanize the fluorine-containing elastomer, generally about 0.1 parts per 100 parts by weight of the fluorine-containing elastomer.
It is preferably used in a proportion of not more than parts by weight, and particularly preferably in a proportion of not more than about 10% based on the quaternary phosphonium compound. If the proportion used is higher than this, the scorch resistance of the fabric will generally be adversely affected, and the crosslinking density of the vulcanizate will become too high, resulting in low elongation. Each component of the vulcanization system may be blended and kneaded as is, or may be diluted and dispersed with carbon black, silica, clay, talc, diatomaceous earth, barium sulfate, etc., or masterbatch dispersion with a fluorine-containing elastomer. May be used as

In addition to the above-mentioned ingredients, conventionally known fillers, reinforcing agents, plasticizers, lubricants, processing aids, pigments, etc. can be appropriately incorporated into the composition of the present invention. Vulcanization is generally carried out after mixing the fluorine-containing elastomer with each of these vulcanization system components and the various additives mentioned above by a commonly used mixing method such as roll mixing, kneader mixing, Banbury mixing, or solution mixing. , by heating. Generally, primary vulcanization is about 140-200℃
for about 2 to 120 minutes at a temperature of
This is carried out by heating at a temperature of 0 to 250°C for about 0 to 30 hours. As shown in the results of the following examples, the fluorine-containing elastomer composition according to the present invention has excellent vulcanization properties, formability during vulcanization molding, dispersibility during kneading processing, storage stability, and processing safety. It has excellent properties, there is no need for moisture absorption or tide moisture during storage, and the vulcanizate has greatly improved compression set and mechanical strength, so it is effective for the various uses mentioned above. It can be used for.

Next, the effects of the present invention will be explained with reference to Examples.

Example 1 Copolymer obtained by copolymerizing vinylidene fluoride and hexafluoropropene in an aqueous medium using acetone as a chain transfer agent and in the presence of ammonium persulfate as a polymerization initiator. Body component molar ratio 78:2
2. Solution viscosity ηSp/CO. 92 (35°C, in acetone, c-1.0), polymer Mooney viscosity ML49 (120
℃): Fluorine-containing raw material 1+ 10 last material A]
The formulations 1 to (12) shown in Table 1 below (numbers with brackets are comparative examples; the same applies hereinafter) were kneaded using an 8-inch mixing roll to form a fluorine-containing elastomer composition. Prepared.

Note that all amounts below are in parts by weight. Regarding the various fluorine-containing elastomer compositions obtained, the viscosity and scorch time (the time required for the viscosity to reach the minimum value + 5), the storage stability and processing of the dough, were evaluated. ) was measured at a measurement temperature of 121°C.

The vulcanization properties were measured using an oscillating disk rheometer (0DR) manufactured by Toyo Seiki Co., Ltd. Further, the composition was press-vulcanized at 180°C for 5 minutes, and then subjected to secondary vulcanization in an oven at 230°C for 22 hours, and the physical properties of each vulcanizate were measured in accordance with JlSK-6301. To measure the compression set, an O-ring with a diameter of 52 m and 71 L was vulcanized and manufactured under the same conditions, and this was
:f) Measured under compression. The results of these measurements are shown in Table 2 below. From the comparison of the results of the inventive examples and comparative examples shown in Table 2, it is clear that the vulcanization system of the present invention has particularly good scorch resistance (storage stability, processing safety) when vulcanizing fluorine-containing elastomers. ) and vulcanization properties (vulcanization rate), but also significantly improved the tensile strength and compression set of the vulcanizate.

Example 2 Regarding the fluorine-containing elastomer A used in Example 1, the formulations 13 to (24) shown in Table 3 below were kneaded using an 8-inch mixing roll to prepare a fluorine-containing elastomer composition. did.

Regarding each of the obtained fluorine-containing elastomer compositions, various physical properties and characteristics were measured in the same manner as in Example 1. The results obtained are shown in Table 4 below. This table 4
From the comparison of the results of the examples of the present invention and the comparative examples shown in , it is clear that the vulcanization system of the present invention maintains an excellent level of scorch resistance and has excellent vulcanization properties when vulcanizing fluorine-containing elastomers. It can be seen that the vulcanization rate, tensile strength and compression set of the vulcanizate were effectively improved.

Example 3 Regarding the fluorine-containing elastomer A used in Example 1, the formulations 25 to (31) shown in Table 5 below were kneaded using an 8-inch mixing roll to form fluorine-containing elastomer compositions. was prepared.

Regarding each of the obtained fluorine-containing elastomer compositions, various physical properties and characteristics were measured in the same manner as in Example 1.

However, vulcanization is performed after press vulcanization at 170°C for 8 minutes.
Secondary vulcanization was performed in an oven at 0°C for 22 hours. Further, a valve stem seal having a shape as described in Japanese Utility Model Publication No. 53-33206 was molded from this composition, and its formability during vulcanization molding was also evaluated. The results obtained are shown in Table 6 below. From the comparison of the results of the examples of the present invention and the comparative examples shown in Table 6, it is clear that the vulcanization system of the present invention has excellent scorch resistance (storage stability, processing safety) when vulcanizing fluorine-containing elastomers. The vulcanizate not only has excellent tensile strength and compression set, but also
It can be seen that good results are also obtained in terms of formability during vulcanization molding.

Example 4 Vinylidene fluoride-tetrafluoroethylene-hexafluoropropene (molar ratio 41:41:18) ternary copolymer [polymer methane] viscosity ML, +1090 (121°C)
; Fluorine-containing elastomer B], the formulations 32 to (35) shown in Table 7 below were kneaded using an 8-inch mixing roll to prepare a fluorine-containing elastomer composition.

Regarding each of the obtained fluorine-containing elastomer compositions, various physical properties and characteristics were measured in the same manner as in Example 1.

Claims (1)

[Scope of Claims] 1 (a) 100 parts by weight of fluorine-containing elastomer, (b)
Divalent metal oxide and/or hydroxide about 1 to 40
Part by weight, (c) polyhydroxy aromatic compound from about 0.5 to
10 parts by weight, (d) General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [ I ] ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [ II
] ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [III] or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [IV] (Here, R
is a dialkylamino group having hydrogen or an alkyl group having 1 to 4 carbon atoms, R_1 is an aralkyl group having 7 to 20 carbon atoms, and R_2 and R_3 are each a dialkylamino group having 1 to 4 carbon atoms.
~24 alkyl group, R_4 is an alkyl group having 1 to 24 carbon atoms or an aralkyl group having 7 to 20 carbon atoms, and R' is an amino group or a group represented by -R_5-OY, where R_5 is an alkylene group having 1 to 8 carbon atoms, and Y is hydrogen, an alkyl group having 1 to 24 carbon atoms, or -
A group represented by COR_6, where R_6 is an alkyl group or aryl group having 1 to 24 carbon atoms, Z is oxygen or a methylene group, and X is a halide, hydroxylate, alkoxylate, carboxylate, phenoxide. , sulfonate, sulfate, sulfite, carbonate, or nitrate); and (e) about 0.1 to 10 parts by weight of a quaternary ammonium compound (e) about 0.1 to 10 parts by weight of a N-alkyl substituted amide compound.
A fluorine-containing elastomer composition containing 1 to 5 parts by weight. 2 (a) 100 parts by weight of fluorine-containing elastomer, (b)
Divalent metal oxide and/or hydroxide about 1 to 40
Part by weight, (c) polyhydroxy aromatic compound from about 0.5 to
10 parts by weight, (d) General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [ I ] ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [ II
] ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [III] or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [IV] (Here, R
is a dialkylamino group having hydrogen or an alkyl group having 1 to 4 carbon atoms, R_1 is an aralkyl group having 7 to 20 carbon atoms, and R_2 and R_3 are each a dialkylamino group having 1 to 4 carbon atoms.
~24 alkyl group, R_4 is an alkyl group having 1 to 24 carbon atoms or an aralkyl group having 7 to 20 carbon atoms, and R' is an amino group or a group represented by -R_5-OY, where R_5 is an alkylene group having 1 to 8 carbon atoms, and Y is hydrogen, an alkyl group having 1 to 24 carbon atoms, or -
A group represented by COR_6, where R_6 is an alkyl group or aryl group having 1 to 24 carbon atoms, Z is oxygen or a methylene group, and X is a halide, hydroxylate, alkoxylate, carboxylate, phenoxide. , sulfonate, sulfate, sulfite, carbonate or nitrate); (e) about 0.1 to 10 parts by weight of a N-alkyl substituted amide compound;
5 parts by weight and (f) 1,8-diazabicyclo[5,4,0] in an amount that does not substantially vulcanize the fluorine-containing elastomer.
undec-7-ene, 1,5-diazabicyclo[4,3
,0] A fluorine-containing elastomer composition containing non-5-ene or 4-dialkylaminopyridine having an alkyl group having 1 to 4 carbon atoms.