JPH02221466A - Treating solution for rubber reinforcing fiber and treatment of rubber reinforcing fiber - Google Patents

Abstract

PURPOSE:To carry out treatment having improved bond strength to rubber free from reduction in strength by repeated flex stress by treating rubber reinforcing fiber with a first solution containing a specific latex and RF condensate and then with a specific overcoating solution. CONSTITUTION:Rubber reinforcing fiber is treated with a first solution containing a latex of a terpolymer of vinylpyridine styrene butadiene, butadiene base or chlorosulfonated polyethylene base and RF condensate, dried, then the bundle is twisted and treated with an overcoating solution containing a vulcanizing agent, a lead compound, an isocyanate and a halogen-containing polymer (preferable example: chlorosulfonated polyethylene) to give rubber reinforcing fiber having improved bond strength to heat-resistant rubber such as especially nitrile rubber, providing rubber products standing uses in a long period of time without reduction in strength even by repeated flex stress at high temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a treatment liquid for rubber reinforcing fibers and a method for treating rubber reinforcing fibers.

[Prior Art] In order to increase the strength of rubber products such as rubber belts and tires, reinforcing am such as glass fiber m yarn is widely used.

Rubber products such as rubber belts are subjected to repeated bending stress, resulting in bending fatigue, resulting in decreased performance, and peeling between the reinforcing material and the rubber matrix is likely to occur.

In order to prevent such peeling or performance deterioration and obtain a sufficient reinforcing effect, it is necessary to increase the compatibility and adhesive strength between the reinforcing fibers and the rubber. be done.

Various compositions of processing agents have been proposed.

For example, various processing agents have been proposed, such as a processing agent using a combination of vinylpyridine-styrene-butadiene terpolymer latex and a water-soluble condensate of resorcinol and formalin, or a processing agent containing rubber latex (Japanese Unexamined Patent Application Publication No. 1983-1992).
114551).

Also, polyisocyanates, polynitroso aromatic compounds,
A treatment liquid containing an acidic halogen-containing polymer has also been proposed (see Japanese Patent Laid-Open No. 14546/1983).

Further, a first liquid (RFL liquid) containing a water-soluble condensate of resorcin formaldehyde and rubber latex is applied to the rubber reinforcing fibers to form a first layer containing the resorcin formaldehyde condensate and rubber on the fibers, and then It is also known to treat with an overcoat liquid containing rubber latex and isocyanate to form a second layer containing isocyanate and rubber (see JP-A-49-14546).

[Problems to be Solved by the Invention] Conventional treatment liquids for rubber reinforcing fibers and conventional methods for treating rubber reinforcing fibers have the following problems.

(1) Sufficient adhesive strength cannot be obtained.

(2) It is difficult to obtain rubber products with sufficient bending strength.

(3) Adhesiveness decreases when used at high temperatures. That is, heat resistance is insufficient.

Recently, with the rise in temperature near automobile engines, heat-resistant rubbers such as chlorosulfonylated polyethylene and hydrogenated nitrile rubber have come to be used as rubber for timing belts. Since such heat-resistant rubber has lower adhesion than ordinary rubber, the above-mentioned drawbacks tend to be greater than that of ordinary rubber, and a timing belt that can withstand long-distance running has not been obtained.

Although the above-mentioned problems can be overcome to some extent by treating the rubber reinforcing fibers with an RFL liquid and then with an overcoat liquid containing rubber latex and isocyanate, this method has the following problems. Has a point.

(1) Adhesive strength decreases over time.

(2) It is necessary to use a large amount of isocyanate in order to obtain a sufficient effect; increasing the amount of isocyanate deteriorates the stability of the solution, and it is necessary to adjust the overcoat solution in small amounts each time it is used. .

(3) The interfacial adhesion between the RFL layer (first layer) and the overcoat liquid (second layer) is poor, and peeling easily occurs between the first and second layers.

The present invention solves the above-mentioned problems of the prior art, and provides rubber reinforcing fibers with high heat resistance that do not reduce adhesive strength over time even when used under conditions of repeated bending stress. By treating the rubber reinforcing fibers with a treatment liquid (RFL liquid) and an overcoat liquid as described in detail below, the rubber reinforcing fibers can be further improved. The purpose is to provide a processing method.

[Means for Solving the Problems] In order to achieve the above object, the present invention uses a water-soluble condensation of a vinylpyridine-styrene-butadiene terpolymer latex or a butadiene-based latex, malolosulfonated bolyene, tyrene latex, and resorcin formaldehyde. A treatment liquid for rubber reinforcing fibers containing vinyl pyridine-styrene is used to treat rubber reinforcing fibers.
Rubber treated with a first liquid containing a terpolymer latex of butadiene or a butadiene-based latex, a chlorosulfonated polyethylene latex and resorcin formaldehyde, and then treated with an overcoat liquid containing a vulcanizing agent, a lead compound, an isocyanate and a halogen-containing polymer. Process the reinforcement tag.

Next, the present invention will be explained in more detail.

A water-soluble condensate of resorcin formaldehyde (hereinafter simply referred to as a condensate) is a resorcin and formaldehyde rich in oxymethyl groups obtained by reacting resorcin and formaldehyde in the presence of an alkaline catalyst such as an alkali hydroxide, ammonia, or an amine. Water-soluble initial addition condensates (resols) can be preferably used. In particular, the molar ratio of resorcin and formaldehyde is 1:0.3 to 2.
．． It is preferable to react at a ratio of 5:5 to 5:5.

As the rubber latex used in the first liquid, a relatively low-heavy latex used as a treatment agent for rubber reinforcing fibers can be suitably used, and there is no limitation, but in particular, butadiene rubber latex, vinylpyridine-styrene, etc. - Terpolymer latex of butadiene (hereinafter referred to as terpolymer latex) is preferred.

As the vinylpyridine-styrene-butadiene terpolymer latex (hereinafter referred to as terpolymer latex), one in which the weight ratio of vinylpyridine, styrene, and butadiene is 10 to 20:10 to 20:60 to 80 is particularly suitable. (Product name, Manufactured by Naugatuck Co., Ltd.), 0650 (Product name 1, Manufactured by Japan Synthetic Rubber)
, N1pol 2518FS (product name.

(manufactured by Nippon Zeon) etc. can be suitably used.

As the butadiene latex, butadiene latex, butadiene-styrene copolymer latex, etc. are suitable, such as 0700 (trade name, manufactured by Japan Synthetic Rubber Co., Ltd.).
, N1pol LXIII (trade name manufactured by Nippon Zeon), etc. can be suitably used.

Although only one of the above terpolymer latex and butadiene latex may be mixed with the CSM latex and condensate described below, it is preferable to use both in combination and mix with the CSM latex and condensate.

The chlorosulfonated polyethylene (CSM) latex has a chlorine content of 20 to 40 wt%, preferably 25
~35wt%, S content in sulfone group is 0.5~2
．． A raw rubber having a Mooney viscosity of 30 to 95 is suitable.

Note that a part of the CSM latex (50 wt% or less, preferably 25 wt% or less) can also be replaced with a latex of chloroprene (CR) or hydrogen nitrile rubber (H-NBR).

Rubber reinforcing mmI treatment liquid (first liquid) containing each of the above-mentioned components
The concentration of the terpolymer latex, butadiene latex, CSM latex, and condensate inside is 10 to 3, respectively.
0 wt%, 3-25 wt%, 0.5-6 wt%, preferably 15-25 wt%, 5-15 wt%, 1-3 wt%,
The total amount of these is 10 to 50 wt% including 2 to 6 wt%.
, preferably 20 to 40 wt%, and the amount of the first liquid applied to the reinforcing fibers is 12 to 25 m fiber weight as solid content.
A suitable amount is 16 to 22 wt%, preferably 16 to 22 wt%.

The first liquid may contain a latex stabilizer, if necessary.
It is also possible to add anti-aging agents and the like.

Next, the overcoat liquid will be explained.

As the halogen-containing polymer, chlorinated rubber, chloroprene, chlorinated polyethylene, chlorinated ethylene-propylene copolymer, chlorinated polyvinyl chloride, chlorosulfonated polyethylene, etc. can be used, but chlorosulfonated polyethylene gives particularly favorable results. .

The chlorosulfonated polyethylene (CSM) latex has a chlorine content of 20 to 40 wt%, preferably 25
~35wt%, S content in sulfone group is 0.5~2
．． Owt% is preferably 1.1 to 1.4 wt%, and raw rubber having a Mooney viscosity of 30 to 95 can be suitably used.

Further, the amount of halogen-containing polymer in the overcoat liquid is 1 to 10 wt%, preferably 2 to 5 wt% as solid content.
% is appropriate. If this amount is too small, the effect of the present invention will not be sufficient, and if this amount is too large, the adhesive strength will tend to decrease.

Incyanate is added to the overcoat liquid.

The amount of isocyanate is between 0.5 and 2. Owt%, preferably 1 to 1.5 wt%, is suitable and can improve adhesiveness.

The amount of isocyanate is about 50% of that of the conventional technology, which is sufficient, and there is no deterioration in bending fatigue or heat resistance that would occur if inocyanate is used in excess, and the stability of the overcoat liquid is improved. increase

The weight percent of the total amount of incyanate and halogen-containing polymer in the overcoat liquid is suitably 3 to 15 wt%, preferably 5 to 10% by weight; if this concentration is too large, the viscosity of the liquid will increase. As a result, unevenness is likely to occur,
If this concentration is too small, the amount of adhesion will decrease and a sufficient effect will not be obtained.

Furthermore, by containing a vulcanizing agent and a lead compound in the overcoat liquid, the adhesiveness and water resistance are further improved.

As a vulcanizing agent, a polynitroso aromatic compound A (for example, p
- dinitrosobenzene), tetrachloropenzoxon,
Examples include poly p-dinitrosobenzene, p, p'-dibenzoyl, benzoquinone dioxime, p-benzoquinone oxime, and tetrachloropenzoxon, poly p-
Particularly preferred are dinitrosobenzene, p,p-dibenzoylbenzoquinone dioxime, and p-benzoquinone dioxime.

The amount of vulcanizing agent in the overcoat liquid is 0.3 to 3 wt%,
Desirably, it is appropriate to set the amount to about 0.6 to 2.5 wt%; if this amount is too small, the effect will not be sufficient and separation will easily occur between the first liquid layer and the second liquid layer. .

Moreover, if this amount is too large, peeling between the rubber matrix and the second liquid layer tends to occur.

Lead compounds include litharge and lead maleate.

Lead phthalate is suitable, and the amount of lead compound in the overcoat solution is suitably from 0.5 to 5 wt%, preferably from 1 to 3 wt%.

The reinforcing fibers to be treated by the method of the present invention are not particularly limited, but it is practical to use glass fibers. Glass fiber can be suitably used.

Arrange three such reinforcing fibers and add 12 ml of the first liquid to them.
~25 wt%, preferably 16~22 wt%, applied according to a conventional method.

After applying the first liquid, preferably after sufficiently drying.

Apply overcoat liquid according to the usual method. It is desirable to dry the first liquid at 200 to 350°C.

The amount of overcoat liquid applied is O, S to reinforcing fibers.
A suitable amount is 5 wt%, preferably 2 to 4 wt%. Preferably at 120-200°C after applying the second liquid
Dry in .

Note: 2.54 cm of reinforcing fiber coated with the above first liquid
(1 inch) of S or Z twist (pre-twist) of about 0.5 to 4.0 per inch is further arranged around 2 to 13 pieces to create a twist of about 0.5 to 3.0 per 2.54 cm. , give the yarn a twist in the opposite direction to the first twist (first twist).

It is desirable to apply an overcoat liquid to this.

Is there any particular limitation on the type of rubber to be reinforced with reinforcing mAl to which the treatment agent of the present invention has been applied?Hypalon, nitrile rubber,
Hydrogenated nitrile rubber can be used as an example, and very suitable results can be obtained, and rubber products such as timing belts with good heat resistance and durability can be obtained.

[Function] Using reinforcing fibers treated with a treatment liquid containing a vinylpyridine-styrene-butadiene terpolymer latex or a butadiene-based latex, a chlorosulfonated polyethylene latex, and a water-soluble condensate of resorcinol formaldehyde; Butadiene terpolymer latex or butadiene-based latex,
Use of reinforcing fibers for rubber reinforcement treated with a first liquid containing chlorosulfonated polyethylene latex and resorcin formaldehyde, and then treated with an overcoat liquid containing a vulcanizing agent, a lead compound, an isocyanate, and a halogen-containing polymer. This prevents the adhesive strength between the rubber (matrix rubber) and the reinforcing fibers from decreasing over time even when used under conditions of repeated stress, and improves the bond between the RFL layer and overcoat layer. Interfacial adhesion and force are increased to prevent peeling, and the amount of isocyanate used is reduced to prevent deterioration of bending fatigue properties and heat resistance when excessive isocyanate is used.

It also prevents performance deterioration due to changes in the overcoat liquid itself over time.

[Example] Vinylpyridine, styrene and butadiene at 15:15
Vinylpyridine-styrene-butadiene terpolymer latex (Pyratex
, trade name, manufactured by Jumanoga Tatsuta Co., Ltd., terpolymer content 41 wt%) 65 parts by weight, butadiene latex (0
700, trade name 1 manufactured by Nippon Synthetic Rubber, butadiene content 57 wt%) 8 parts by weight, C5M latex (450, trade name manufactured by Steel Chemical Co., Ltd., CSM content 40 wt%) 4 parts by weight, addition of resorcin and formaldehyde 15 parts by weight of an aqueous solution containing 20 wt% of condensate (resol), 12 parts by weight of water
parts by weight of the mixture, and 1 part by weight of a mineral oil emulsion (mineral oil content: 55 wt%) as an anti-aging agent.

Add 1 part by weight of ammonia water (concentration 18 wt%) to the first
I got the liquid.

Resurge 0.05 parts by weight, chlorosulfonated polyethylene (Hypalon 40, trade name, manufactured by Showa Neoprene Co., Ltd.)
6 parts by weight, polyisocyanate (MR-200, trade name, manufactured by Nippon Polyurethane Co., Ltd.) 1.1 parts by weight, p, p'-
Dibenzoylbenzoquinone dioxime (vulcanizing agent) 1.5
Parts by weight of toluene were added to obtain an overcoat liquid having a concentration of 10 wt%.

The first liquid was applied to 3 glass fiber bundles made of 200 glass fibers of 9 diameters in a conventional manner (solid content 17 wt%). After drying at 250°C for 1 minute, the glass fiber bundles were 4.0 times of Z twist (pre-twist) per 2.54 cm, and 13 fiber bundles to which this pre-twist has been applied are arranged to give 2.1 times of S twist (pre-twist) per 2.54 cm. A second liquid was applied to the treated material (solid content 3%), and this was
A test piece was prepared by drying it at 0° C. for 1 minute and using it as a reinforcing fiber.

Type of rubber: 100 parts by weight of hydrogenated nitrile rubber: 40 parts by weight of carbon black, 5 parts by weight of zinc white, 1 part by weight of stearic acid, 2 parts by weight of anti-aging agent.

Contains 3 parts by weight of vulcanization accelerator and 5 parts by weight of plasticizer.

Preparation of Test Pieces Using rubber having the above composition, four timing belts were prepared according to a conventional method.

Using this timing belt, a belt running test was carried out for 600 hours in an atmosphere of 100° C., and the decrease in strength was measured.

The above test results are shown in the attached table.

[Comparative Example] In place of the first solution in the above example, a treatment solution containing the same contents of other components but not containing CSM was used, and the results of the same experiment are shown in the attached table.

Separate table It has great adhesion even when used with adhesives.

By reducing the amount of isocyanate used, it is possible to prevent deterioration of bending fatigue resistance and heat resistance.

The overcoat liquid can be stored for a long period of time, and no peeling occurs between the first layer and the overcoat layer.

[Effects of the Invention] Rubber products reinforced with fibers treated with the treatment agent of the present invention have high heat resistance, do not lose strength even when subjected to repeated bending stress, and can be used for long periods of time.

Claims (2)

[Claims] (1) A treatment liquid for rubber reinforcing fibers containing a terpolymer latex of vinylpyridine-styrene-butadiene or a butadiene-based latex, a chlorosulfonated polyethylene latex, and a water-soluble condensate of resorcin formaldehyde. (2) After treatment with a first liquid containing a vinylpyridine-styrene-butadiene terpolymer latex or a butadiene-based latex, a chlorosulfonated polyethylene latex, and resorcin formaldehyde, a vulcanizing agent,
A method for treating rubber reinforcing fibers with an overcoat liquid containing a lead compound, an isocyanate, and a halogen-containing polymer.