JPH0735460B2 - Acrylic rubber composition for hoses, coatings, or rolls - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is based on a novel carboxyl group-containing acrylic rubber excellent in vulcanization rate, tensile strength and compression set, and a hose material, a covering material, Alternatively, it relates to an acrylic rubber composition useful for roll applications.

[Conventional technology]

Acrylic rubber is an elastomer whose main component is acrylic acid ester. Since the main chain of this acrylic acid ester polymer does not have a double bond, it has been conventionally practiced to copolymerize a crosslinking monomer serving as a crosslinking point.

Known examples of such crosslinking monomers include halogen group-containing compounds, epoxy group-containing compounds, carboxyl group-containing compounds, and diene compounds. Among these, as a carboxyl group-containing compound, acrylic acid, methacrylic acid, mono-n-butyl maleate, etc. are known, and an epoxy compound vulcanizing agent and a vulcanization accelerator are added to a carboxyl group-containing acrylic rubber using them. A vulcanized compound in which and are compounded has also been proposed (Japanese Patent Publication No. 6-8007). However, in this vulcanized compound, vulcanization is too early to cause scorch in the processing step, physical properties such as vulcanized physical properties and compression set are not sufficient, and practically unsatisfactory. Was wanted.

[Problems to be solved by the invention]

The present invention has been made against the background of the above-mentioned conventional technical problems, shows an optimal vulcanization rate, and has excellent tensile strength and compression set, a hose material, a coating material, or an acrylic resin useful for rolls. An object is to provide a rubber composition.

[Means for solving problems]

The present invention relates to an acrylic rubber composition in which an acrylic compound containing an acrylic ester as a main component is mixed with an epoxy compound as a vulcanizing agent, and the acrylic rubber is the following (A) to
The present invention provides an acrylic rubber composition for a hose material, a covering material, or a roll, which is obtained by copolymerizing the component (C). (A) Alkyl (meth) acrylate and / or alkoxyalkyl (meth) acrylate 70-99.9% by weight, (B) Carboxyl group-containing unsaturated compound represented by the following general formula (I) (hereinafter referred to as "compound (I)"). And)
Or a carboxyl group-containing unsaturated compound represented by the following general formula (II) (hereinafter referred to as "compound (II)") 0.1 to 30
weight%, (In the formula, R ¹ is a hydrogen atom or a methyl group, R ² is a carbon atom of 1 to
An alkylene group of 10, an integer of 1 to 5, R ³ is an alkylene group of 1 to 5 carbon atoms, and R ⁴ is a hydrocarbon group of 1 to 7 carbon atoms. ), And 0 to 20% by weight of another monomer copolymerizable with the components (A) and (B).

Specific examples of the alkyl (meth) acrylate and / or the alkoxyalkyl (meth) acrylate of the monomer (A) component constituting the acrylic rubber of the present invention include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl. (Meth) acrylate, butyl (meth)
Acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth)
Acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate,
Alkyl (meth) acrylates such as cyanoethyl (meth) acrylate; and alkoxyalkyl (meth) acrylates such as methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, ethoxypropyl (meth) acrylate. Can be mentioned.

These alkyl (meth) acrylates and / or alkoxyalkyl (meth) acrylates may be used alone or in combination of two or more.

The proportion of component (A) is 70 to 99.9% by weight, preferably 90 to
If it is less than 70% by weight, the resulting acrylic rubber becomes hard, which is not preferable. On the other hand, if it exceeds 99.9% by weight, the amount of the component (B) introduced becomes small, and the effect of the present invention is obtained. I can't.

The carboxyl group-containing unsaturated compound which is the component (B) is a compound represented by the general formula (I) or the general formula (II).

Here, R ¹ in the compound (I) is a methyl group or a hydrogen atom, and preferable R ² is an alkylene group having 1 to 10 carbon atoms such as ethylene group, (iso) propylene group, butylene group and hexylene group.

Examples of the compound (I) include the following.

α-vinyl-ω-carboxy-poly (carbonyloxyethylene), α-isopropenyl-ω-carboxy-poly (carbonyloxyethylene), α-vinyl-ω-carboxy-poly (carbonyloxypentamethylene),
α-isopropyl-ω-carboxy-poly (carbonyloxypentamethylene.

On the other hand, preferable R ³ in the compound (II) has 1 carbon atom such as ethylene group, (iso) propylene group and butylene group.
To 5 alkylene groups.

Further, preferable R ⁴ in the formula is a hydrocarbon group having 1 to 7 carbon atoms such as a phenylene group, a cyclohexylene group, an ethylene group, a butylene group and a hexylene group.

Examples of the compound (II) include the followings.

[Succinic acid mono- (methacrylooxyethyl) ester], [Maleic acid mono- (methacrylooxyethyl) ester], [Phthalic acid mono- (methacryloxyethyl) ester], [Hexahydrophthalic acid mono- (methacrylooxyethyl) ester], succinic acid mono- (acrylooxyethyl) ester, maleic acid mono- (acrylooxyethyl) ester, phthalic acid mono- (acrylooxyethyl) ester Ester, hexa-hydrophthalic acid mono- (acrylooxyethyl)
Ester, succinic acid mono- (meth) acrylooxypropyl ester, maleic acid mono- (meth) acrylooxypropyl ester, phthalic acid mono- (meth) acrylooxypropyl ester, hexahydrophthalic acid mono- (meth) Acrylooxypropyl ester, adipic acid mono- (meth) acrylooxyethyl ester, malonic acid mono- (meth) acrylooxyethyl ester, adipic acid mono- (meth) acrylooxypropyl ester, malonic acid mono- ( (Meth) acrylooxypropyl ester.

Such component (B) can be used alone or in combination of two or more.

The ratio of the component (B) is 0.1 to 30% by weight, preferably 1 to 1
If it is less than 0.1% by weight, the desired effects of the present invention such as poor tensile strength and compression set of acrylic rubber cannot be obtained. On the other hand, if it exceeds 30% by weight, heat resistance deteriorates, which is not preferable. .

In the acrylic rubber of the present invention, the above (A) to
20% by weight or less of another monomer copolymerizable with the component (B), for example, at least one compound selected from the group consisting of monovinyl unsaturated compounds, monovinylidene unsaturated compounds and monovinylene unsaturated compounds. It can also be polymerized.

Specific compounds of such components include, for example, styrene,
Examples include vinyltoluene, α-methylstyrene, vinylnaphthalene, halogenated styrene, acrylonitrile, methacrylonitrile, acrylamide, N-methylolacrylamide, vinyl acetate, vinyl chloride and vinylidene chloride.

In addition, these components are used as needed, and it is appropriate that the amount of this component is not more than 20% by weight.

The acrylic rubber produced by the present invention has a Mooney viscosity ML _{1 + 4} (100 ° C.) of preferably 30 to 100, more preferably 40 to 70.

The structure of the acrylic rubber of the present invention includes infrared absorption spectroscopy,
It can be confirmed by a nuclear magnetic resonance analysis method, a neutralization titration method, or the like.

The acrylic rubber is composed of 70 to 99.9% by weight of the component (A),
A mixture of 0.1 to 30% by weight of the component (B) and 0 to 20% by weight of other copolymerization components is emulsion-polymerized or suspended in an aqueous medium using a radical polymerization initiator at a polymerization temperature of 0 to 80 ° C. It can be easily produced by turbid radical polymerization or solution radical polymerization in an organic solvent.

In the case of producing an acrylic rubber by emulsion radical polymerization, a generally known method, for example, potassium sulphate as a polymerization initiator, a normal radical initiator such as a peroxide or an azo compound is used, and an emulsifier is used. Any one of anionic, cationic, nonionic and amphoteric surfactants or a mixed system is used, and in the presence of a molecular weight modifier such as mercaptans such as t-dodecyl mercaptan or a halogenated hydrocarbon compound, 0-80 Emulsion polymerization is carried out at a temperature of ℃, and after reaching a predetermined polymerization conversion rate, N, N
-A reaction terminator such as diethylhydroxylamine is added to terminate the polymerization reaction, then unreacted monomers in the latex obtained are removed by steam distillation or the like, and antioxidants such as phenols and amines are added, and An acrylic rubber can be obtained by mixing latex with an aqueous solution of a metal salt such as an aqueous solution of aluminum sulfate and an aqueous solution of calcium chloride to coagulate the latex and then drying.

Further, in the case of producing a copolymer by suspension radical polymerization, polyvinyl alcohol saponification product or the like is added as a dispersant, and polymerization is performed using an oil-soluble radical initiator such as azobisisobutyronitrile or benzoyl peroxide. After the completion of the polymerization and removing the water, a polymer can be obtained.

Further, when producing a copolymer by solution radical polymerization, a generally known method can be adopted.

The polymerization method may be either continuous or batch.

The carboxyl group-containing acrylic rubber obtained by the present invention includes carbon black, white carbon, calcium carbonate and other fillers, colorants, foaming agents, flame retardants, softeners, thickeners, zinc oxide, stearin, if necessary. Well-known additives such as an acid, an epoxy compound vulcanizing agent, a vulcanization accelerator, and an anti-aging agent are blended as necessary and used as an acrylic rubber composition.

Thus, the acrylic rubber composition obtained by the present invention is easy to control the vulcanization rate, which is a drawback of the conventional carboxyl group-containing acrylic rubber, it is possible to improve the tensile strength, compression set. It is useful for various sealing materials such as gaskets, oil seals, O-rings, packings, various belts, various hoses, rolls, and covering materials.

〔Example〕

 Hereinafter, the present invention will be described more specifically with reference to examples.

In the examples,% and parts represent% by weight and parts by weight unless otherwise specified.

Examples 1 to 8 and Comparative Examples 1 to 4 100 parts of the monomer mixture shown in Table 1, 4 parts of sodium lauryl sulfate and 0.2 parts of potassium persulfate were charged into a nitrogen-substituted iron container and heated at 50 ° C. for 15 to 20. Polymerization was carried out for a time, and after the polymerization was almost completed, the reaction product was taken out and steam was blown into it to remove unreacted monomers. The acrylic rubber latex thus obtained is added to a 0.25% calcium chloride aqueous solution to coagulate (at this time, about 5% of the rubber content of calcium chloride is used), and the coagulated product is thoroughly washed with water to about 90 ° C. In 3
Allow to dry for ~ 4 hours.

Further, 100 parts of the acrylic rubber obtained as described above, 1.0 part of stearic acid, 60 parts of HAF carbon black (Tokai Carbon Co., Ltd., Seast 3), 1-o-tolyl biguanide (Ouchi Shinko Co., Ltd.) Nox Cellar BG), 1 part of n-dodecyltrimethylammonium bromide (manufactured by Wako Pure Chemical Industries, Ltd.) and a vulcanizing agent shown in Table 2 were kneaded with a roll to obtain an acrylic rubber composition.

Next, using this acrylic rubber composition, Mooney scorch and vulcanization rate were measured, and the results are shown in Table 2.

The Mooney scorch was measured according to JIS K6300.

Further, the vulcanization rate was measured (170 ° C.) by a JSR curastometer type III.

Further, the vulcanizate was measured by preparing an unvulcanized rubber sheet from the acrylic rubber composition, using a vulcanizing press with a pressure of 100 kg / cm ² , 170 ° C. for 30 minutes and using a gear oven for 175
The mixture was vulcanized at 4 ° C for 4 hours, and the properties of the vulcanized product were measured according to the method of JIS K6301. The results obtained are shown in Table 2.

From these results, the acrylic rubber of the present invention (Examples 1 to 1)
It can be seen that in 8), the scorch resistance and the vulcanization rate are optimal, and the tensile strength and compression set characteristics are superior to those of the acrylic rubbers of Comparative Examples 1 to 4.

[Effects of the Invention] The acrylic rubber composition obtained by the present invention exhibits optimum vulcanization rate and scorch characteristics, and also has good tensile strength and compression set. Utilizing these properties, various hose materials such as oil cooler hose, air duct hose, power steering hose, control hose, intercooler hose, torque converter hose, oil return hose, heat resistant hose; bearing seals, various oil seals, O- Used for sealing materials such as rings, packings, gaskets; various diaphragms, rubber plates, belts, oil level gauges, hose masking, piping insulation materials, etc .; rolls, etc. Since the acrylic rubber used in the present invention has good oil resistance and heat resistance, it is possible to improve the oil resistance and heat resistance of these rubbers and resins by mixing with various rubbers or resins. You can At that time, it is also effective to powderize and mix the acrylic rubber.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display location C08L 63/00 NJP C09D 133/14 PGC 163/00 PKE (72) Inventor Engyo Hiroji Tokyo Central 2-11-24, Tsukiji, Japan (56) References JP-A-55-58275 (JP, A) JP-A-60-76752 (JP, A)

Claims (1)

[Claims] 1. An acrylic rubber composition comprising an acrylic rubber mainly composed of an acrylic ester and an epoxy compound as a vulcanizing agent, wherein the acrylic rubber is one of the following (A) to
An acrylic rubber composition for a hose material, a covering material, or a roll, which is obtained by copolymerizing the component (C). (A) Alkyl (meth) acrylate and / or alkoxyalkyl (meth) acrylate 70 to 99.9 wt% (B) Carboxyl group-containing unsaturated compound represented by the following general formula (I) and / or the following general formula (II) Carboxyl group-containing unsaturated compound represented by 0.1 to 30% by weight (In the formula, R ¹ is a hydrogen atom or a methyl group, R ² is a carbon atom of 1 to
An alkylene group of 10, n is an integer of 1 to 5, R ³ is a carbon number of 1 to
5 is an alkylene group, and R ⁴ is a hydrocarbon group having 1 to 7 carbon atoms. ) (C) 0 to 20% by weight of another monomer copolymerizable with the components (A) and (B)