JPS6362548B2 - - Google Patents

Description

[Detailed description of the invention]

Industrial Application Field The present invention relates to a curable fluorine-containing elastomer vulcanized composition, and more specifically, a fluorine-containing elastomer vulcanized composition that has significantly improved compression set and excellent heat resistance, oil resistance, and chemical resistance. The present invention relates to a fluorine-containing elastomer vulcanizate composition that provides an elastomer vulcanizate and has excellent vulcanization properties, kneading processability, processing stability, storage stability, etc. Prior Art Highly fluorinated elastomer vulcanizates have excellent heat resistance, oil resistance, chemical resistance, etc., and are therefore used in various industrial fields, such as automobiles, ships, aircraft, hydraulics, and general machinery industries. It is widely used in fields such as pollution-related sectors as sealing materials such as O-rings and gaskets, diaphragms, hoses, rolls, and sheet materials. When a fluorinated elastomer vulcanizate is used for such purposes, it is necessary that the vulcanizate has particularly low compression set. Conventionally, vulcanization of fluorine-containing elastomers has been carried out using aliphatic diamines or organic peroxides as crosslinking agents. However, this method has poor scorch resistance (processing stability, storage stability), and the resulting vulcanizate has a large compression set, making it not necessarily suitable for the above-mentioned uses. . Therefore, it has been desired to develop a fluorine-containing elastomer vulcanizate composition that has both sufficient curing speed and scorch resistance, and can provide a vulcanizate with a small compression set. Recently, in order to meet these demands, a crosslinking method using a polyhydroxy compound with improved scorch resistance and compression set has been put into practical use. In this vulcanization system, as a vulcanization accelerator, for example, a quaternary phosphonium salt (Japanese Patent Publication No. 51-11138,
(Japanese Patent Publication No. 51-11655), quaternary ammonium salts (Japanese Patent Publication No. 49-17018, Japanese Patent Publication No. 52-38072, Japanese Patent Publication No. 57-20333), 8-alkyl (or aralkyl)-1, Quaternary ammonium salts of 8-diaza-bicyclo[5,4,0]-7-undecene (Japanese Patent Publication No. 52-8863), aminophosphinic acid derivatives (Japanese Patent Publication No. 58-17222), etc. are used. ing. However, even when these vulcanization systems are used, the compression set of the vulcanizate is low, especially at high temperatures.
It is also not at a fully satisfactory level. moreover,
During vulcanization molding, in order to manufacture molded products with particularly complex shapes or thick objects, reducing the vulcanization accelerator and slowing down the vulcanization rate can cause adhesion between the mold and the vulcanizate, resulting in defects. At the same time, the mold is contaminated. Furthermore, when quaternary ammonium salts are used, in addition to the above-mentioned disadvantages, they tend to absorb moisture and deliquesce significantly during storage, so special consideration is required for storage, which may not only cause problems in handling but also However, there are drawbacks such as deterioration of vulcanization properties and vulcanization physical properties. Problems to be Solved by the Invention The purpose of the present invention is to meet these demands, to have excellent vulcanization properties, kneading processability, processing stability, storage stability, etc., and to have a small compression set, and to be superior to conventional It is an object of the present invention to provide a fluorine-containing elastomer vulcanizate composition capable of producing a vulcanizate having excellent heat resistance, oil resistance, chemical resistance, etc., similar to the fluorine-containing elastomer vulcanizate. Means for Solving the Problems As a result of extensive research, the present inventors found that a compound having a specific phosphorus-nitrogen-phosphorus bond was used as a vulcanization accelerator, and a polyhydroxy compound and a divalent metal were used as a vulcanizing agent. It has been discovered that a composition using an oxide or a divalent metal hydroxide and blending these into a specific fluorine-containing elastomer copolymer can meet the above-mentioned purpose, and based on this knowledge, the present invention has been developed. We have finally completed the process. That is, the present invention provides (A) an elastomer copolymer having a vinylidene fluoride unit and at least one other fluorine-containing monomer unit; (B) a copolymer having the general formula [R ¹ in the formula is an aryl group, or an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a cyano group, -NR ³ ₂ ( However, R ³ has at least one substituent selected from an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, an aryl group, or a hydrogen atom), and a halogen atom. It is a substituted aryl group, ^R2 is an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms, and X is a halogen ion, hydroxide ion, or sulfate ion. , thiosulfate ion, nitrate ion, nitrite ion, acetate ion,
cyano ion, thiocyano ion, tetraphenylborate ion or perchlorate ion], (C) polyhydroxy compound and (D) divalent metal oxide or divalent metal hydroxide, or their The present invention provides a fluorine-containing elastomer vulcanized composition containing the mixture. Note that the electric charge of X in the general formula () is not limited to monovalent, but also includes multivalent ions based on the atom or atomic group of X. The elastomer copolymer used as component (A) in the vulcanized composition of the present invention has a vinylidene fluoride unit and at least one other fluorine-containing monomer unit, and the at least one Examples of other fluorine-containing monomer units include hexafluoropropene, 1,1,1,2,3-pentafluoropropene, 3,3,3-trifluoropropene, tetrafluoroethylene, trifluoroethylene, 1 , 2-difluoroethylene, dichlorodifluoroethylene, chlorotrifluoroethylene, hexafluorobutene, fluorinated vinyl ethers, fluorinated alkyl vinyl ethers,
Examples include perfluoroacrylic acid esters, and particularly important are hexafluoropropene, pentafluoropropene, and tetrafluoroethylene. Specific examples of the elastomer copolymer of component (A) include vinylidene fluoride-hexafluoropropene copolymer, vinylidene fluoride-hexafluoropropene-1,1,1,2,3-pentafluoropropene copolymer, and vinylidene fluoride-hexafluoropropene copolymer. Examples include polymers, vinylidene fluoride-hexafluoropropene-tetrafluoroethylene copolymers, and the like. Vulcanization of these copolymers is performed by converting the double bonds produced by a chemical dehydrofluorination reaction of hydrogen in molecules such as vinylidene fluoride units and pentafluoropropene units in the copolymers into crosslinking points. It is done as. The vulcanization accelerator used as component (B) in the vulcanization composition of the present invention is a compound represented by the general formula (), and specific examples thereof include bis(methyldiphenylphosphine) iminium tetra Phenylborate, bis(methyldiphenylphosphine)
iminium chloride, bis(butyldiphenylphosphine) iminium bromide, bis(dodecyldiphenylphosphine) iminium brolide, bis(tetradecyldiphenylphosphine) iminium chloride, bis(hexadecyl Diphenylphosphine) iminium chloride, bis(cyclohexyldiphenylphosphine) iminium chloride, bis(benzyldiphenylphosphine) iminium chloride, bis(benzyldiphenylphosphine) iminium acetate, bis [Benzyldi(4-methoxyphenyl)phosphine] iminium chloride, bis[benzyldi(4-fluorophenyl)phosphine] iminium chloride, bis[benzyldi(4-chlorophenyl)phosphine]
iminium chloride, bis[benzyl (4-
Bromophenyl)phosphine] iminium chloride, bis[benzyldi(4-cyanophenyl)phosphine] iminium chloride, bis[benzyldi(4-dimethylaminophenyl)phosphine] iminium chloride, bis[4-
Methylbenzyldi(4-methylphenyl)phosphine] iminium chloride, bis(2,4-
dimethylbenzyldiphenylphosphine) iminium chloride, bis(4-methoxybenzyldiphenylphosphine) iminium chloride, bis(4-chlorobenzyldiphenylphosphine) iminium chloride, bis(4-chlorobenzyl Diphenylphosphine) iminium chloride, bis(4-bromobenzyldiphenylphosphine) iminium chloride, and the like. Among these compounds, the typical component (B) is bis(benzyldiphenylphosphine) iminium chloride, which is classified as
und Allgemeine Hemie (Zeitschrift fur)
Anorganische und allgemeine Chemie), 492
Vol., pp. 122-134 (1984). As the polyhydroxy compound used as component (C) in the vulcanized composition of the present invention, at least one compound selected from polyhydroxy aromatic compounds and fluorine-containing polyhydroxy aliphatic compounds is preferably mentioned. Examples of polyhydroxy aromatic compounds include bisphenol A, bisphenol AF, resorcinol, 1,3,5-carbon trihydroxybenzene, 1,7-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,
6-dihydroxynaphthalene, 4,4'-dihydroxydiphenyl, 4,4'-dihydroxystilbene, 2,6-dihydroxyanthracene, hydroquinone, catechol, 2,2-bis(4-hydroxyphenyl)butane, 4,4 -Bis(4-hydroxyphenyl)valeric acid, 2,2-bis(4-
hydroxyphenyl)tetrafluorodichloropropane, 4,4'-dihydroxydiphenylsulfone, 4,4'-dihydroxydiphenylketone, tri(4-hydroxyphenyl)methane, 3,3',
5,5'-tetrachlorobisphenol A, 3,
3',5,5'-tetrabromobisphenol A and the like are used as fluorine-containing polyhydroxy aliphatic compounds, such as CF ₂ (CF ₂ CH ₂ OH) ₂ and HOCH ₂
(CF ₂ ) ₄ OCF (CF ₃ ) CH ₂ OH, HOCH ₂ (CF ₂ ) ₂ OCF
( _CF3 ) _CH2OH , _CF2 ( _CFHCF2CH2OH ) _{2 ,}
(CF ₂ ) ₃ (CF ₂ CH ₂ OH) ₂ , (CF ₂ ) ₃
(CFHCF ₂ CH ₂ OH) ₂ , (CF ₂ ) ₅ (CF ₂ CH ₂ OH) ₂ ,
(CF ₂ ) ₅ (CFHCF ₂ CH ₂ OH) ₂ and the like. Particularly preferred polyhydroxy compounds among these are bisphenol AF and hydroquinone, which may also be alkali metal salts or alkaline earth metal salts. These compounds may be used alone or in combination of two or more. Divalent metal oxides, divalent metal hydroxides, or mixtures thereof used as component (D) in the vulcanized composition of the present invention include, for example, magnesium, zinc,
Oxides or hydroxides of divalent metals such as calcium, lead, etc., or mixtures thereof, which may contain from 1 to 70% by weight of metal salts of weak acids. Examples of metal salts of this weak acid include stearates, benzoates, carbonates, oxalates, and phosphites of barium, sodium, potassium, lead, calcium, and the like. Regarding the blending ratio of each of the above-mentioned components in the vulcanized composition of the present invention, for 100 parts by weight of component (A),
Component (B) is 0.05 to 2.0 parts by weight, preferably 0.1 to 1.0 parts by weight, and component (C) is 0.1 to 10 parts by weight, preferably 0.6 to 1.0 parts by weight.
5.0 parts by weight and component (D) in an amount of 1 to 30 parts by weight, preferably 2 to 20 parts by weight. In the vulcanized composition of the present invention, if necessary,
Other ingredients, such as fillers and reinforcing agents such as carbon black, silica, clay, diatomaceous earth, and talc, plasticizers, and coloring agents, may be added as long as they do not depart from the gist of the present invention. , one or more conventionally known vulcanizing agents and accelerators may be blended. The vulcanized composition thus obtained is vulcanized according to a conventional method. This vulcanization method includes, for example, a method in which the mixture is kneaded in a roll-type rubber mill or a Banbury mixer, placed in a mold and pressurized for primary vulcanization, and then secondary vulcanization. Generally, the conditions for primary vulcanization are a temperature of 100 to 210°C, a time of 3 to 180 minutes, and a pressure of 20 to 100 kg/ ^cm2 , and the conditions for secondary vulcanization are a temperature of 150 to 300°C and a time of 0 to 30 minutes. A time range is used. In addition, other vulcanization methods include a method of preforming such as injection or extrusion, and then vulcanizing it;
Alternatively, a solution or dispersion is prepared using one or more of ketones such as methyl ethyl ketone, acetone, and cyclohexanone, and ethers such as methyl ethyl ether, diethyl ether, dioxane, and tetrahydrofuran. It is also possible to use a method of coating and vulcanizing the surface of a film, sheet, plate, tube, pipe, tank, large container, or other molded product. Effects of the Invention The fluorine-containing elastomer vulcanizate composition of the present invention is excellent in vulcanization properties, kneading processability, processing stability, storage stability, etc., and the fluorine-containing elastomer vulcanizate obtained therefrom is characterized by particularly low compression set, and also has excellent heat resistance, oil resistance, and chemical resistance, similar to fluorine-containing elastomer vulcanizates obtained using conventionally known vulcanizing agents. Thus, the vulcanized composition of the present invention has extremely high industrial value. EXAMPLES Next, the present invention will be explained in more detail with reference to Examples. Reference Example: Production of bis(benzyldiphenylphosphine) iminium chloride 3.15 mmol of [(C ₆ H ₅ ) ₂ P] ₂ NH was dissolved in 30 ml of benzene, and diluted with 10 ml of benzene.
Add 3.15 mmol of butyllithium-hexane solution and reflux while boiling for 1 hour. Then, after cooling to room temperature, 6.30 ml of benzyl chloride was added dropwise to form a white precipitate. The solvent is then distilled off and the residue is mixed with 35 ml of ethyl ether and refluxed while boiling. The white precipitate formed is filtered and washed twice with 15 ml of ethyl ether. Further dissolve in 15ml of ethanol and 10ml
of petroleum ether, white crystals of bis(benzyldiphenylphosphine) iminium chloride are formed. This is filtered and dried under vacuum (10 ^-3 torr) overnight. The yield of this stuff is 70%
The melting point was 255°C. Example 1 Vinylidene fluoride-hexafluoropropene-tetrafluoroethylene (67:
13:20 mol%) fluorine-containing elastomer copolymer
Wrap 100 parts by weight around two rolls, add 30 parts by weight of MT carbon black, 6 parts by weight of calcium hydroxide, magnesium oxide, (Kiyowa Mag #150)
After kneading 3 parts by weight of bisphenol AF, 2.0 parts by weight of bisphenol AF, and 0.55 parts by weight of bis(methyldiphenylphosphine) iminium tetraphenylborate, the mixture was left to mature overnight. After that, knead it again, put it into a mold, and heat it up.
Press vulcanization was performed at 177℃ for 10 minutes, and the sheet and o
-Each molded into a ring. Next, it was taken out from the mold and heated in an air circulation furnace at a temperature of 232°C for 24 hours to complete the secondary vulcanization. Note that Shore hardness (JIS-A), modulus, tensile strength, and elongation were all measured according to JIS K 6301. In addition, the compression set is determined by compressing an O-ring (inner diameter 23.7 mm, thickness 3.5 mm) by 25%.
Placed in the oven at 200℃ for 72 hours, ASTM D-396-61
It was measured according to method B of . Furthermore, the vulcanization test was conducted using a disk rheometer at 177℃ and the vibration frequency.
It was conducted under the conditions of 3 cpm and 3° amplitude. The vulcanization characteristics, mechanical properties, and compression set of the molded product thus obtained are shown in the table. Example 2 In the vulcanized composition of Example 1, 0.55 parts by weight of bis(methyldiphenylphosphine)iminium tetraphenylborate was replaced with bis(benzyldiphenylphosphine)iminium obtained in Reference Example. A vulcanized composition was prepared in the same manner as in Example 1, except that 0.45 parts by weight of chloride was used, and various tests were conducted. The results are shown in the table. Example 3 In the vulcanized composition of Example 1, in place of the fluorine-containing elastomer copolymer of Example 1, vinylidene fluoride having a Mooney viscosity of 36 (using a 121° C. ML rotor) obtained by emulsion polymerization was used. A vulcanized composition was prepared in the same manner as in Example 1, except that a fluorine-containing elastomer copolymer of hexafluoropropene (75:25 mol %) was used, and various tests were conducted.
The results are shown in the table. Example 4 In the vulcanized composition of Example 1, bis(benzyldiphenylphosphine)iminium acetate was substituted for 0.55 parts by weight of bis(methyldiphenylphosphine)iminium tetraphenylborate.
A vulcanized composition was prepared in the same manner as in Example 1, except that 0.45 parts by weight was used, and various tests were conducted. The results are shown in the table. Example 5 In the vulcanized composition of Example 1, bis(2,4-
Except for using 0.47 parts by weight of dimethylbenzyldiphenylphosphine) iminium chloride.
A vulcanized composition was prepared in the same manner as in Example 1, and various tests were conducted. The results are shown in the table. Example 6 In the vulcanized composition of Example 1, bis[benzyldi(4-methoxyphenyl)phosphine]iminium chloride was used instead of 0.55 parts by weight of bis(methyldiphenylphosphine)iminium tetraphenylborate. Except using 0.54 parts by weight,
A vulcanized composition was prepared in the same manner as in Example 1, and various tests were conducted. The results are shown in the table.

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Claims (1)

[Scope of Claims] 1 (A) an elastomer copolymer having vinylidene fluoride units and at least one other fluorine-containing monomer unit, (B) general formula [R ¹ in the formula is an aryl group, or an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a cyano group, -NR ³ ₂ ( However, R ³ is an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, an aryl group, or a hydrogen atom) and a halogen atom. It is an aryl group, ^R2 is an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms, and X is a halogen ion, hydroxide ion, sulfate ion, thiosulfate ion, nitrate ion, nitrite ion, acetate ion, cyano ion, thiocyano ion, tetraphenylborate ion or perchlorate ion], (C) polyhydroxy compound and (D) A fluorine-containing elastomer vulcanized composition comprising a valent metal oxide, a divalent metal hydroxide, or a mixture thereof.