JPH05239300A - Fluororubber vulcanizing composition - Google Patents

Abstract

PURPOSE:To obtain a fluoroelastomer vulcanizing composition having excellent vulcanizing speed and superb rubberiness and tensile properties (tensile strength, elongation, etc.). CONSTITUTION:The objective fluoroelastomer composition comprises an elastomeric copolymer comprising vinylidene fluoride units and at least one other fluorinated monomer units, a vulcanizing accelerator comprising triphenylphosphine substituted by an alkoxy group, phenoxy group or both the groups or at least one salt thereof, a polyol crosslinking agent, and a bivalent metal oxide, bivalent metal hydroxide or mixture thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curable fluororubber vulcanizing composition, and more specifically, it has an improved vulcanization rate and excellent vulcanization physical properties, heat resistance, oil resistance and chemical resistance. The present invention relates to a vulcanized composition of fluororubber.

[0002]

2. Description of the Related Art Conventionally, as a vulcanization accelerator in vulcanization of aromatic polyol, for example, a quaternary phosphonium salt (Japanese Patent Publication No.
1-111138), quaternary ammonium salt (Japanese Patent Publication No. 52-38072), 8-alkyl (or aralkyl) -1,8-diaza-bicyclo [5,4,0].
-7-Undecene quaternary ammonium salt (JP-B-52
-8863), aminophosphinic acid derivatives (Japanese Patent Publication No. 58-17222), bis (triarylphosphine) iminum salts (European patent publication 120,
462-A) and the like are known.

It is known that a tertiary phosphine such as triphenylphosphine also has some vulcanization accelerating ability, but the vulcanization rate is small and it is not practical.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to develop a tertiary phosphine vulcanization accelerator which has an excellent vulcanization rate and is practical.

[0005]

DISCLOSURE OF THE INVENTION As a result of intensive studies on the vulcanization accelerating ability of various tertiary phosphine compounds, the present inventors have found that triphenyl substituted with an alkoxy group, a phenoxy group, or both groups. The inventors have found that phosphine has an excellent vulcanization rate, especially tris (2,6-dimethoxyphenyl) phosphine is outstanding, and that it has an excellent balance with tensile properties, and has completed the present invention.

That is, the present invention provides an elastomeric copolymer (B) having a vinylidene fluoride unit and at least one other fluorine-containing monomer unit (B) with an alkoxy group or a phenoxy group, or both groups. Vulcanization accelerator (C) polyol cross-linking agent consisting of substituted triphenylphosphine, or a salt of at least one of these, and (D) divalent metal oxide or divalent metal hydroxide or these A fluoroelastomer vulcanizing composition comprising a mixture of

Specific examples of the elastomer copolymer having the vinylidene fluoride unit of the component (A) and at least one other fluorine-containing monomer unit as referred to in the present invention include vinylidene fluoride-hexafluoropropene copolymer. Combined, vinylidene fluoride-hexafluoropropene-1,1,1,
2,3-pentafluoropropene copolymer, vinylidene fluoride-hexafluoropropene-tetrafluoroethylene copolymer and the like can be mentioned. The vulcanization of these copolymers uses a double bond generated by a dehydrofluorination reaction by a chemical method of hydrogen in a molecule such as vinylidene fluoride unit or pentafluoropropene unit in the copolymer as a cross-linking point. Done.

In the present invention, a typical vulcanization accelerator consisting of triphenylphosphine or a salt thereof, which is substituted with an alkoxy group and / or a phenoxy group of the component (B), which is a particularly important component, is used. As a thing,
Tris (4-methoxyphenyl) phosphine, tris (2,6-dimethoxyphenyl) phosphine, tris (4-phenoxyphenyl) phosphine or tris (2,6-dimethoxyphenyl) phosphine, tris (4-phenoxy) -2,6-dimethoxyphenyl) phosphine, or their phosphates, acetates, hydrochlorides,
Examples thereof include hydrofluoric acid salts. The blending amount of component B is preferably 0.05 to 5 parts by weight per 100 parts by weight of component (A).

The polyol cross-linking agent of the component (C) in the present invention includes at least one compound selected from polyhydroxy aromatic compounds and fluorine-containing polyhydroxy aliphatic compounds. Bisphenol AF is mainly used, but bisphenol A, hydroquinone,
44'- dihydroxy diphenyl sulfone, 44'- dihydroxy diphenyl ketone, aromatic polyhydroxy compounds, such _{as, CF 2 (CF 2 CH 2} OH) 2, HOCH 2 (CF 2) 2 OCF (CF 3) CH 2 OH Fluorine-containing polyhydroxy aliphatic compounds such as Further, these may be alkali metal salts or alkaline earth metal salts, or two or more kinds may be used in combination.

The divalent metal oxide or divalent metal hydroxide or mixture thereof used as the component (D) in the vulcanized composition of the present invention is, for example, an oxide of a divalent metal such as magnesium, zinc, calcium or lead. Or a hydroxide or a mixture thereof, which may contain 1 to 70% by weight of a metal salt of a weak acid. As the metal salt of this weak acid,
Examples thereof include stearates such as barium, sodium, potassium, lead and calcium, benzoates, carbonates, oxalates and phosphites.

In the vulcanized composition of the present invention, if necessary, other components such as fillers such as carbon black, silica, clay, diatomaceous earth, talc and the like, reinforcing agents, plasticizers, colorants and the like are added. Further, one or more conventionally known vulcanizing agents and accelerators may be blended within a range not departing from the gist of the present invention. In order to further increase the accelerating ability of the vulcanization accelerator, dimethyl sulfone,
44'-dichlorodiphenyl sulfone, dimethyl sulfoxide, etc. may be blended. The vulcanized composition thus obtained is vulcanized in a conventional manner.

Examples of the vulcanization method include a method in which after kneading with a roll type rubber mill or Banbury mixer, the mixture is put into a mold and pressurized to perform primary vulcanization, and then secondary vulcanization. Generally, a temperature of 100 to 210 is used as the condition for primary vulcanization.
C, time 3 to 180 minutes, pressure 20 to 100 kg / cm ²
Is in the range of 150 to 30 as the condition for secondary vulcanization.
A range of 0 ° C. and 0 to 30 hours is adopted. As other vulcanization means, a method of vulcanizing after preforming such as injection or extrusion, or ketones such as methyl ethyl ketone, acetone, cyclohexanone, ethers such as methyl ethyl ether, diethyl ether, dioxane, tetrahydrofuran, etc. Of 1 or 2 or more of the above are used as a medium to prepare a solution or dispersion, which is used for paper, fiber, film, sheet, metal plate, tube, pipe, tank,
It is also possible to use a method in which the surface of a large container or other molded article is coated and vulcanized.

The fluorinated elastomer vulcanizate of the present invention is
Since it has excellent heat resistance, oil resistance, chemical resistance, etc., it can be used in various industrial fields such as automobiles, ships, aircraft,
It is widely used as a sealing material for o-rings, gaskets, etc., diaphragms, hoses, rolls, sheet materials, etc. in fields such as hydraulics, general machinery industry, and pollution-related departments.

[0014]

The present invention will be described in more detail with reference to the following examples.

[0015]

Examples 1-5, Comparative Examples 1-3 Mixing roll (2
(This roll) kneads the materials having the mixing ratios shown in Table 1,
Incidentally, the compounding amount of the phosphine compound of various vulcanization accelerators was taken as a part of the equimolar amount, and the vulcanization characteristics (18) were measured by Monsanto Company Rheometer ODR2000.
0 ° C.) was measured. The rest was left to stand overnight for aging, kneading was performed again, and the mixture was put into a mold at a predetermined temperature and press-molded. The obtained press-vulcanized sheet was heated at 232 ° C. for 24 hours,
Oven vulcanized. After left overnight, JIS K-6301
Based on the above, the tensile properties and hardness were measured. The results are shown in Table 2.

As shown in Comparative Examples 1 to 3, triphenylphosphine, which is a conventional reference, tris (4-methylphenyl) phosphine, tris (p-chlorophenyl).
When phosphine is used as the vulcanization accelerator, the proper vulcanization time (90% of the vulcanization degree expressed by the difference between the highest viscosity and the lowest viscosity)
Since the time to reach the point Tc90) was large and the vulcanization rate was considerably slow, it was not practical, but tris (4-methoxyphenyl) phosphine and tris (2,6-dimethoxy) shown in Examples 1 to 5 were used. It was found that the vulcanization rate was extremely high when phenyl) phosphine and acetate were used as the vulcanization accelerator. In terms of tensile properties, it was a value sufficient for rubber and was a practical vulcanization accelerator.

[0017]

[Table 1]

[0018]

[Table 2]

[0019]

INDUSTRIAL APPLICABILITY The present invention uses a triphenylphosphine substituted with an alkoxy group or a phenoxy group or both as a polyol-vulcanized fluororubber vulcanization accelerator, and thus provides a fluoroelastomer vulcanized composition with excellent vulcanization. Since it has the effect of giving speed, excellent rubber elasticity and tensile properties (tensile strength, elongation), its industrial value is great.

Claims (2)

[Claims] 1. An elastomer copolymer having (A) a vinylidene fluoride unit and at least one other fluorine-containing monomer unit, and (B) substituted with an alkoxy group or a phenoxy group or both groups. In addition, a vulcanization accelerator, a (C) polyol cross-linking agent and (D) a divalent metal oxide, a divalent metal hydroxide or a mixture thereof, which comprises triphenylphosphine or a salt of at least one of these compounds. A fluoroelastomer vulcanizing composition comprising: 2. The vulcanized composition according to claim 1, wherein the component (B) is tris (2,6-dioxyphenyl) phosphine.