JPH0324371A - Rubber composition for sealing material - Google Patents

Abstract

PURPOSE:To provide a rubber composition for sealing material with excellent airtightness, elasticity, heat resistance and productivity by forming the rubber composition from rubber components containing conjugate diene butyl rubber by more than 20 weight% and cross linking agents. CONSTITUTION:Conjugate diene butyl rubber containing a conjugate diene unit is used singly as rubber component or while in admixture with a rubber compound of butyl rubber, haloganated butyl rubber and the like. The rate of the conjugate diene butyl rubber is more than 20 weight% of the rubber composition in order to secure heat resistance and airtightness. Sulfur, organic peroxide, a polyole cross linking agent, an amine cross linking agent and the like are added as cross linking agents to the rubber composition. Compounding agents of several kinds for normal use are, if needed, added thereto. In order to cross link this rubber composition, primary cross linking is carried out after molding while heating and pressurizing the composition, and the composition is further heated, if needed, for secondary cross linking. A rubber composition for sealing material, excellent in airtightness, elasticity and heat resistance is thus obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a rubber composition for sealing materials, and more particularly to a rubber composition for sealing materials that has excellent airtightness, flexibility, and heat resistance.

Butadiene-acrylic nitrile copolymer rubber (NBR), ethylene-propylene copolymer rubber, etc. are used as packing materials for condensers or sealing.
JP 61-21177, JP 61-130360),
The former has poor heat resistance, and the latter has poor airtightness (gas permeability).

Furthermore, although butyl rubber has excellent airtightness, it has problems such as a slow vulcanization rate during sulfur vulcanization, lowering productivity, and inability to crosslink with peroxide. Therefore, there has been a demand for a rubber material for sealing materials that is flexible, has excellent airtightness, heat resistance, and productivity.

[Problems to be Solved by the Invention] The present invention has been made in the light of the above-mentioned conventional technical problems, and provides a rubber composition for sealing materials having excellent airtightness, flexibility, heat resistance, and productivity. The purpose is to provide something.

[Means for Solving the Problems] The present inventors provide a rubber composition for a sealing material, which is characterized by comprising a rubber component containing 20% by weight or more of conjugated diene butyl rubber and a crosslinking agent. .

The conjugated diene butyl rubber used in the present invention is a butyl rubber containing conjugated diene units, and the preferable content of the conjugated diene units is 0.1 to 10 mol%, more preferably 0.1 to 10 mol%. It is 5 to 5 mol%. Conjugated diene butyl rubber can be produced, for example, by the following method.

■ Halogenated butyl rubber can be treated with metal alcoholates, reduced metals, or ZnO/RCOOH, (RCOO
)2 Zn/RCOOH/CaO, (RCOO)2 Z
n/(RCOO)2Ca (wherein, R has 1 to 1 carbon atoms
30 alkyl, aralkyl, or aryl groups. ) and other dehydrohalogenation agents (U.S. Pat. No. 3,965,213, JP-A-48-90385, JP-A-Sho. 53-42289
Publication No. 14363, Japanese Patent Publication No. 57-14363, Japanese Patent Publication No. 1987-14363
84901).

■ A method in which alkali metals such as lithium, potassium, or sodium are added to butyl rubber, and then metal dehydrogenation is performed.

■ A method of modifying polyisoptylene, butyl rubber, or halogenated butyl rubber by treating it with a quinone compound such as chloranil or naphthoquinone in a solution or solid state.

The rubber component in the rubber composition of the present invention is the above-mentioned conjugated diene butyl rubber alone, or this and other rubber components,
That is, at least one member selected from ordinary butyl rubber, halogenated butyl rubber, chlorinated polyethylene rubber, shrimp chlorohydrin rubber, chlorosulfonated polyethylene rubber, polyisobutylene, ethylene propylene rubber, acrylonitrile butadiene rubber, chloroprene rubber, etc. Used by blending with rubber. Among the above, butyl rubber, halogenated butyl rubber, and ethylene-propylene rubber are preferred.

The proportion of conjugated diene butyl rubber in the rubber is 20% by weight.
The content is preferably 50% by weight or more.

If the amount of conjugated diene butyl rubber is less than 20% by weight, a material with good heat resistance and airtightness cannot be obtained.

Examples of the crosslinking agent used in the present invention include sulfur, organic peroxides, polyol crosslinking agents, amine crosslinking agents, and resin crosslinking agents.

When using sulfur as a crosslinking agent, it is 0.01 to 10 parts by weight, preferably 0.01 to 10 parts by weight, per 100 parts by weight of the rubber component.
Use about 1 to 5 parts by weight.

As the organic peroxide as a crosslinking agent, for example, 2,5-
Dimethyl-2,5-di(t-butylperoxy)hexane-3, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,2'-bis(t-butylperoxy) )-p-diisobutylbenzene, dicumyl peroxide, di-t-butyl peroxide, t-butyl benzoate, 1,1-bis(t-butylperoxy)3,3. , 5-trimethylcyclohexane, 2.4-
Dichlorobenzoyl peroxide, penzoyl peroxide, p-chlorobenzoyl peroxide, t-butyl peroxybenzoate, di-t-butyl peroxy isophthalate, etc. are used.

In addition, since it is suitable for high-temperature crosslinking, 2,5-dimethyl-2
．． 5-di(t-butylperoxy)hexyne-3, 2.
5-dimethyl-2,5-di(1-butylbaroxy)
Hexane, 2,2'-bis(t-butylperoxy)
Preferred are p-diisobutylbenzene, t-butylperoxybenzoate, and di-t-butylperoxyisophthalate.

When using an organic peroxide as a crosslinking agent, it is used in an amount of 0.01 to 10 parts by weight, preferably 0.05 to 5 parts by weight, based on 100 parts by weight of the rubber component.

When using an organic peroxide, a difunctional vinyl monomer or the like can be used as a crosslinking aid. Examples of such crosslinking aids include the following compounds.

That is, ethylene dimethacrylate, 1,3-butylene dimethacrylate, 1,4-butylene dimethacrylate, 1,6-hexane dimethacrylate, polyethylene glycol dimethacrylate, 1,4-butane dimethacrylate, Acrylate, 1,6-hexanediol diacrylate, 2,2'-bis(4-
methacrylic diethoxyphenyl) propane, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, bentaerythritol triacrylate, divinylbenzene, N,N'-methylenebisacrylamide, p-quinonedioxime, p.
These include p'-dibenzoylquinone dioxime, tetrachlorobenzoquinone, penzoquinone, triazinedithiol, triallyl cyanurate, triallyl isocyanurate, bismaleimide, and silicone oil with a high vinyl content.

The blending amount of this crosslinking aid is preferably 0.00 parts by weight per 100 parts by weight of the rubber component. 1 to 10 parts by weight, more preferably 0. It is 5 to 7 parts by weight.

When a polyol crosslinking agent is used as a crosslinking agent, polyhydroxy aromatic compounds such as hydroquinone, bisphenol A1, bisphenol AF, and salts thereof are preferably used.

Furthermore, fluorine-containing aliphatic siols are also used.

The amount of these polyol crosslinking agents added is 10% of the rubber composition.
It is usually about 0.1 to 20 parts by weight, preferably about 1 to 10 parts by weight per 0 parts by weight.

In addition, examples of polyol crosslinking accelerators used in combination with the polyol crosslinking agent include methyltrioctylammonium chloride, benzyltriethylammonium chloride, and tetrahexylammonium tetrafluoroborate.
quaternary ammonium compounds such as 8-methyl-1,8-diazacyclo(5,4.0)-7-undecenyl chloride, penzyltriphenylphosphonium chloride, m-trifluoromethylbenzyltrioctylphosphonium Quaternary phosphonium compounds such as chloride, benzyltrioctylphosphonium bromide are preferred.

The amount of such a crosslinking accelerator added is usually about 0.2 to 10 parts by weight per 100 parts by weight of the rubber component.

When using an amine crosslinking agent, various alkyl amines such as hexamethylene diamine, tetraethylenebentamine, and triethylene tetramine, various aromatic amines such as aniline, pyridine, and diaminobenzene, and the carbamic acids and cinnamylidene of these amines are used. Salts of fatty acids such as acids can be used.

The amount of the amine crosslinking agent added is usually 0.1 to 10 parts by weight, preferably 0.1 to 10 parts by weight, per 100 parts by weight of the rubber component.
It is about 5 to 5 parts by weight.

When using a resin crosslinking agent, methylolated alkylphenol formaldehyde resin, brominated alkylphenol formaldehyde resin, etc. are used.

The amount of the resin crosslinking agent added is usually 0.1 to 30 parts by weight, preferably 1 to 2 parts by weight per 100 parts by weight of the rubber component.
It is approximately 0 parts by weight.

In addition to the crosslinking agent, various commonly used compounding agents can be added to the rubber component. These compounding agents may be added during the process of producing the rubber composite of the present invention, or may be added after producing the composition, if necessary.

Fillers include carbon black, silica, calcium carbonate, miryoku, fine quartz powder, diatomaceous earth, zinc white, basic magnesium carbonate, aluminum silicate,
Examples include calcium metasilicate, titanium dioxide, talc, aluminum sulfate, calcium sulfate, barium sulfate, asbestos, glass fiber, organic reinforcing agents, organic fillers, and magnetic powders such as ferrite, samarium, and neodymium.

Examples of dispersion aids include higher fatty acids and their metal salts or amide salts, plasticizers such as polydimethylsiloxane oil, diphenylsilanediol, trimethylsilanol, phthalic acid derivatives, adipic acid derivatives, and softeners such as lubricants. oil, process oil, coal tar, castor oil, calcium stearate, anti-aging agents such as phenylene diamines, phosphates, quinolines, cresols, phenols, dithiocarbamate metal salts, heat-resistant agents such as oxidation Iron, cerium oxide, potassium hydroxide, iron naphthenate, potassium naphthenate, and other colorants, ultraviolet absorbers, flame retardants, oil resistance, improvers, foaming agents, scorch inhibitors, tackifiers, lubricants, etc. as desired. Can be mixed.

In order to crosslink the rubber composition of the present invention, after molding, usually 1
Several minutes to several hours at 00 to 250℃, 0 to 200 kg/c
Primary crosslinking under pressure of d, further as necessary 150~2
Secondary crosslinking is performed at 50°C for 1 to several hours to obtain a crosslinked product.

[Example] Hereinafter, the present invention will be explained in more detail with reference to Examples.

In addition, various measurements in the examples were based on the following methods.

The physical properties and heat resistance of the crosslinked product of the composition of the present invention are determined according to JIS
Evaluation was made in accordance with K6301.

Regarding airtightness, dimethylformamide was placed in a container, the container was sealed with the prepared crosslinked product, and the presence or absence of leakage was evaluated.

Regarding productivity, t of the test using a culastometer
'clo, t' Evaluation was made based on the c90 value (the smaller the value, the higher the productivity).

Examples 1 to 5, Comparative Examples 1 to 4 Based on the formulation of Table 1, kneading was performed using a 250cc plastomill to obtain a rubber composition, which was then formed into a sheet and pressed at 160°C for 30 minutes. A crosslinked product was prepared by sulfurization. This crosslinked product was used to evaluate physical properties. The results are shown in Table-2.

In Examples 1 to 5 of the present invention, rubber compositions targeted by the present invention were obtained. On the other hand, Comparative Examples 1 and 2 are examples outside the scope of the present invention in which only butyl rubber and chlorinated butyl rubber were used as the rubber component, and the heat resistance was poor. Comparative Example 3 is an example outside the scope of the present invention in which only ethylene-brobylene rubber was used as a rubber component, and the airtightness is poor. Comparative Example 4 was obtained by using a different crosslinking agent from Comparative Example 3, but the airtightness and heat resistance were still poor.

The following margin [Effects of the invention] The rubber assembly of the present invention has a good vulcanization rate and is excellent in productivity, and the crosslinked product obtained by crosslinking it has excellent airtightness, flexibility, and heat resistance. Therefore, it is suitable as a sealing material.

The sealing material of the present invention is a material used to prevent the leakage of liquid substances, gaseous substances, solid substances, etc. Specifically, it is used as a packing material for capacitors of electrical components, sealed bottles, etc. This includes lids, various sealing materials, and various other packing materials.

Claims (1)

[Claims] (1) A rubber composition for a sealing material comprising a rubber component containing 20% by weight or more of conjugated diene butyl rubber and a crosslinking agent.