JPS63270877A - Glass fiber cord for reinforcing rubber - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a glass fiber cord for reinforcing rubber, which has improved adhesive strength to heat-resistant rubber.

[Summary of the invention]

The present invention provides a rubber-reinforcing glass fiber cord in which the glass fiber cord has a specific coating composition, thereby improving the adhesion between the glass fiber cord and heat-resistant rubber.

[Conventional technology]

Conventionally, glass fiber cords for reinforcing rubber used in timing belts, tires, rubber hoses, etc. have been coated with a mixed liquid of resorcinol-formalin (RF) resin and rubber latex (L) (RF L liquid), and then formed by drying. It has a coating. This coating improves the adhesion between the rubber and glass fibers. Various proposals have been made regarding the R/F ratio and the type of rubber latex, and the rubber latex includes vinyl-gin-styrene-butadiene copolymer latex, styrene-butadiene rubber latex, neoprene rubber latex, butadiene rubber latex, etc. is used (Special Publication No. 47-37513,
JP-A No. 50-42194, etc.). Such conventional rubber-reinforcing glass fiber cords exhibit good adhesion to chloroprene rubber.

[Problem that the invention seeks to solve]

In recent years, the demand for heat-resistant rubber has increased in various fields.For example, in the case of automotive timing belts, the heat-resistant requirements for belts have become stricter as the temperature in automobile engine compartments increases, and belt materials have changed from chlorobrene to hydrogenated nitrile rubber. (H-NBR, highly saturated polymer rubber containing nitrile groups). However, the coating applied with RFL liquid on the conventional glass fiber cord mentioned above has insufficient heat resistance and has low adhesive strength with heat-resistant rubber, so belts using this cord have a short lifespan. It has the disadvantage of being short. In order to improve the adhesion of this conventional glass fiber cord, treatment with a secondary treatment agent such as rubber glue made of a gasoline solution of a rubber compound is known (eg, Japan Adhesive Association Journal Vol. 1.7). No. 5 (1971) p. 23~
29) has not been able to overcome the drawback of short belt life due to insufficient heat resistance of the secondary treatment agent.

[Means for solving problems]

As a result of intensive research to solve the above problems, the inventors of the present invention have found that a coating that has good adhesion to heat-resistant rubber, especially H-NBR, and has excellent heat resistance even without secondary treatment. It was possible to obtain a rubber-reinforcing glass fiber cord having the following properties, and the present invention was completed. That is, the present invention relates to a rubber-reinforcing glass fiber cord coated with a composition mainly consisting of a resorcinol-formalin condensate and a nitrile group-containing highly saturated polymer rubber having an iodine value of 120 or less.

The nitrile group-containing highly saturated polymer rubber used in the present invention needs to have an iodine value of 120 or less from the viewpoint of rubber film strength and adhesive strength to heat-resistant rubber, and this iodine value is 0 to 1OO. It is preferable that there be
Note that the iodine value is a value determined according to JIs KOO70.

This nitrile group-containing highly saturated polymer rubber is obtained by hydrogenating the conjugated diene unit portion of an unsaturated nitrile-conjugated diene copolymer rubber; Unsaturated nitrile-ethylenically unsaturated monomer copolymer rubber in which the conjugated diene unit portion is hydrogenated; vinyl norbornene,
It may be substituted with a non-conjugated diene such as dicyclopentadiene or 1,4-hexadiene and copolymerized.

These nitrile group-containing highly saturated polymer rubbers are specifically hydrogenated rubbers such as butadiene-acrylonitrile copolymer rubber, isoprene-butadiene-acrylonitrile copolymer rubber, and isoprene-acrylonitrile copolymer rubber; butadiene-methyl acrylate-acrylonitrile. Copolymer rubber, butadiene-acrylic acid-acrylonitrile copolymer rubber, etc. and their hydrogenated products; butadiene-ethylene-acrylonitrile copolymer-t, butyl acrylate-ethoxyethyl acrylate-vinyl chloroacetate-acrylonitrile copolymer rubber, butyl Examples include acrylate-ethoxyethyl acrylate-vinylnorbornene-acrylonitrile copolymer rubber, which can be obtained by using ordinary polymerization techniques and ordinary hydrogenation methods.

The weight ratio of resorcin and formalin in the resorcin-formalin (RF) condensate is preferably 1:0.5.
-3, more preferably 1:1-2.

The weight ratio of the RF condensation alloy to the nitrile group-containing highly saturated polymer rubber is preferably 1:5 to 15, more preferably 1:8 to 13.

The amount of said coating is preferably 1% relative to the glass fiber cord.
It is 0 to 25% by weight, more preferably 15 to 20% by weight.

The rubber-reinforcing glass fiber cord of the present invention is produced by attaching a predetermined amount of an aqueous mixture of a resorcin-formalin condensate and the nitrile group-containing highly saturated polymer rubber latex to the glass fiber cord in a conventional manner. It is obtained by heat treatment at a temperature of 200 to 300°C.

Here, the nitrully group-containing highly saturated polymer rubber latex can be usually prepared by a phase inversion method. That is, a solution of a nitrile group-containing highly saturated polymer rubber and an emulsifier aqueous solution are mixed, the rubber is emulsified and dispersed as fine particles in water by strong stirring, and the solvent is further removed to obtain a nitrile group-containing highly saturated polymer rubber latex. is obtained. Examples of the solvent include aromatic solvents that are soluble in the rubber, such as benzene, toluene, and xylene; halogenated hydrocarbon solvents, such as dichloroethane and chloroform; methyl ethyl ketone;
Ketones such as acetone and ethers such as tetrahydrofuran are used alone or in combination.

The emulsifier used in the aqueous emulsifier solution includes commonly known fatty acids such as oleic acid and stearic acid, potassium salts and sodium salts such as rosin acid, alkylbenzene sulfonic acid, and alkyl sulfate, and polyoxyethylene-based nonionic emulsifiers. These can be used alone or in combination. As a stirrer for emulsification and dispersion, various homo mixers, ultrasonic emulsifiers, etc. are used.

Removal of the solvent from the emulsion is performed by a known method such as a steam stripping method.

In the aqueous mixture used for manufacturing the rubber-reinforcing glass fiber cord of the present invention, a resorcin-chlorophenol formaldehyde co-condensate (e.g. Valkabond E manufactured by Eva ICI) is used instead of the resorcin-formalin condensate.
) may be used, or both may be used in combination. Also,
The aqueous mixture may contain a filler such as carbon black, a vulcanizing agent, and a vulcanization accelerator, if necessary.

〔Example〕

Examples of the present invention will be shown below, but the present invention is not limited thereto. In the following description, parts and percentages are based on weight.

Hydrogenated nitrile rubber with an iodine value of 28 “Zetpo120”
20'' (manufactured by Zeon Corporation) was dissolved in a mixed solvent of 450 g of methyl ethyl ketone and 450 g of cyclohexane. To this solution, 3 g of potassium oleate, 1 g of polyoxyethylene nonyl phenyl ether, and 0.1 g of potassium hydroxide were added and stirred. Add 1.000 g of water to the solution thus obtained, and mix at room temperature using a TK-Homo Mixer M type (manufactured by Tokushu Kika Kogyo Co., Ltd.) for 10.OOOr.
Strong stirring was performed for 10 minutes at pm. From the obtained emulsion,
The solvent was removed by steam stripping, and then concentrated using an evaporator until the solid content was approximately 30%.
An aqueous dispersion of was obtained. Further, the mixture was centrifuged at room temperature and 3.0 OOrp- for 15 minutes to remove excess emulsifier and concentrate to obtain Zetpol 2020 latex with a solid content of 40%.

This latex and resorcin(R)-formalin CF)
A processing agent was prepared using the following formulation using an aqueous solution (solid content: 6%) of a condensate (R/F = 1/1.5).

Aqueous solution of resorcinol-formalin condensate---m
-・------i o o part Zetpol 2020
Latex ゛−−−−−−−−−−−−…゛150 parts water −・−・−・−・−2
5 parts This treatment agent was applied to glass fiber strands (filament diameter 9 μm, 1st count 150 yards/bond) so that the solid content adhesion rate was 18%, and after heat treatment at 250°C for 1 minute, the prescribed number of strands were combined. The glass fiber cord (A) for rubber reinforcement of this example was obtained by twisting.

As an evaluation test for this glass fiber cord (A), tests were conducted for its adhesion to a hydrogenated nitrile rubber compound having the following formulation and its heat aging resistance.

Hydrogenated nitrile rubber compound: (part) Zetpol 2020
100Zn011
5 stearic acid 1
Carbon Black SRF (manufactured by Asahi Carbon Co., Ltd.) 40 Thiokol TP95 (manufactured by Toshi Thiokol Co., Ltd.) 5 Sulfur
0.5 Tsukucellar TT (manufactured by Iriuchi Shinko Chemical Industry Co., Ltd.) 1.5 Tsukucellar CZ
(manufactured by Iriuchi Shinko Kagaku Kogyo Co., Ltd.) 1.0 Place the hydrogenated nitrile rubber compound on the glass fiber cord of this example,
A bonded body sample of a glass fiber cord and a hydrogenated nitrile rubber compound was prepared by press vulcanization at 50° C. for 30 minutes. For this sample, the adhesive strength before heat aging test and 13
The adhesive strength of each sample was measured after heat aging at 0° C. for 1 to 10 days.

For comparison, a treatment agent was prepared using the following formulation.

Water −・・−−−−−−1～
−−・−1−−・−−−−・−25 parts Using this treatment agent, a glass fiber strand (filament diameter 9 μm,
Rubber reinforcing glass fiber cord (B
), and the same test as above was conducted. In addition, the hydrogenated nitrile rubber compound of this example was mixed with methyl ethyl ketone 8
Rubber glue is obtained by dissolving it in a mixed solvent of 0 parts and 20 parts of toluene to make it 15%, and using this rubber glue, apply it to the glass fiber cord (B) so that the solid content adhesion rate is 2%. After drying at room temperature, it is heat-treated at 120° C. for 5 minutes to obtain a glass fiber cord (C). Then, the same test as above was conducted.

The results obtained are shown in the table below.

〔Effect of the invention〕

According to the present invention, the adhesion between the glass fiber cord and the heat-resistant rubber is improved, and the heat resistance of a reinforced rubber product using this cord can be increased. By reinforcing hydrogenated nitrile rubber, which is a heat-resistant rubber, with the glass fiber cord of the present invention, a timing belt with a long life can be obtained.

Claims (1)

[Claims] A glass fiber cord for rubber reinforcement coated with a composition mainly consisting of a resorcinol-formalin condensate and a nitrile group-containing highly saturated polymer rubber having an iodine value of 120 or less.