JPH0450237A - Glass cord for reinforcing rubber - Google Patents

Abstract

PURPOSE:To provide the subject cord having excellent tensile strength and flexural fatigue by forming a layer containing a specific condensed product, etc., and subsequently a layer containing a methacrylate salt, a vulcanizing agent, etc., on a core line comprising a high strength glass fiber. CONSTITUTION:The first layer containing a resorcinol-formaldehyde condensed product and a rubber latex (in an amount of 16-22wt.% as a solid content based on the weight of fibers) and subsequently the second layer containing a methacrylic acid salt or acrylic acid salt (e.g. zinc salt), an isocyanate compound, a halogen-containing polymer (e.g. chloroprene) and a vulcanizing agent (e.g. tetrachlorobenzoquinone), respectively, are formed on a core line comprising high strength glass fibers each having a diameter of <=8mu preferably 3-5mu (having a tensile strength of >=300kg/mm<2>) and subsequently the second layer containing a methacrylic or acrylic acid salt (zinc salt), an isocyanate compound, a halogen- containing polymer (e.g. chloroprene) and a vulcanizing agent (e.g. tetrachlorobenzoquinone) on a core line comprising high strength glass fibers (preferably having a tensile strength of >=300kg/mm<2>) having a diameter of <=8mu, preferably 3-5mu, to provide the objective cord.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rubber reinforcing glass coat, particularly to a rubber reinforcing glass coat suitable for reinforcing a timing belt for a vehicle.

[Prior Art] Reinforcing fibers such as glass fiber yarns are widely used to increase the strength of rubber products such as rubber belts and tires.

Rubber products such as rubber belts are subjected to repeated bending stress, which causes bending fatigue, resulting in a decrease in performance, and tends to cause peeling between the reinforcing material and the rubber matrix.

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, and for this reason, it is necessary to apply a treatment agent to the surface of the reinforcing fibers. 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 a terpolymer latex of vinyl-gin-styrene-phtadiene and a water-soluble condensate of resorcinol and formaldehyde, or a processing agent containing rubber latex (Japanese Unexamined Patent Application Publication No. 1983-1982). (Refer to Publication No.-114551).

Furthermore, a treatment liquid containing an isocyanate, a nitroso aromatic compound, and 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 M containing a resorcin formaldehyde condensate and rubber on the fibers, and then It is also known to form a second layer containing isocyanate and rubber by treating with an overcoat liquid containing rubber latex and isocyanate (see Japanese Patent Laid-Open No. 14546/1983).

[Invention or problem to be solved] Conventional 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, the heat resistance is insufficient.

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

Is it possible to solve the above-mentioned problems to some extent by treating the rubber reinforcing fibers with an RFL solution and then with an overcoat solution containing rubber latex and isocyanate?This method is as follows. It has some problems.

(1) Adhesive strength decreases over time.

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

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

The present inventor has solved the above-mentioned problems of the prior art, and has developed a rubber reinforcement with high heat resistance that does not reduce adhesive strength over time even when used under conditions of repeated bending stress. After repeated studies, we developed the first fiber containing resorcin formaldehyde condensate and rubber latex.
layer, methacrylate or acrylate on top of the first layer;
an isocyanate, and a second comprising a halogen-containing polymer.
Layered rubber reinforcement edge! (hereinafter referred to as optical invention).

The present invention aims to solve the above-mentioned problems of the prior art, further improve the tensile strength of rubber reinforcing fibers, and further improve the bending fatigue resistance.

[Means for Solving the Problems] In order to achieve the above object, in the present invention, a diameter of 8
High strength glass below μ a! A first layer containing a resorcin formaldehyde condensate and rubber latex is formed on the core wire consisting of i, and a second layer containing a methacrylate or an acrylate, an isocyanate, a halogen-containing polymer, and a vulcanizing agent is formed on the first layer. A glass cord with reinforced rubber reinforcement is used.

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

Tensile strength is 300kg/1I as high strength glass fiber
112 or more glass fibers, particularly those having the following composition, can be suitably used.

5iQ255~δ5 wt% A120320~26 wt% CaO (1-10wt% Mg07~12wt% 8□0.0~1wt% R200~0.5*t% Also, the diameter of the glass fiber is 8 or less, preferably 7. Defined as 5μ or less.

If the diameter of the glass fiber is too large, it will be difficult to obtain a sufficient effect.

Further, the diameter of the glass fibers may be set to 3μ or more, preferably 5μ or more, but if the diameter is made too small, the manufacturing cost increases.

A water-soluble condensate of resorcin formaldehyde (hereinafter simply referred to as a condensate) includes the oxymethyl group of resorcin and formaldehyde obtained by reacting resorcin and formaldehyde in the presence of an alkaline catalyst such as an alkali hydroxide, ammonia, or an amine. Water-rich initial addition condensates (resols) are preferably used. In particular, the molar ratio of resorcin and formaldehyde is 1:0.3~
It is preferable to react at a ratio of 2.5.

The rubber latex used in the first liquid to form the first layer is preferably a latex with a relatively low degree of polymerization that is used as a treatment agent for rubber reinforcing fibers, and is not particularly limited. Butadiene rubber latex, vinyl gin-styrene-butadiene terpolymer latex (hereinafter referred to as terpolymer latex)
Medium or terpolymer latex is preferred.

Examples of butadiene rubber latex include 0700 (product name, manufactured by Japan Synthetic Rubber Co., Ltd.) and N1pol LXIII.
(trade name, manufactured by Nippon Zeon Co., Ltd.), etc., or as a terpolymer latex, one with a weight ratio of vinyl, lysine, styrene, and butadiene in a range of 20:10 to 20:50 to 80 is particularly suitable. (trade name, manufactured by Sumitomo Naugatuck Co., Ltd.), 0650 (trade name, manufactured by Japan Synthetic Rubber Co., Ltd.), N1pol 2518FS (trade name, manufactured by Nippon Zeon Co., Ltd.), etc. can be suitably used.

Furthermore, it is more effective to use a butadiene latex and a terpolymer latex in combination.

In this case, the total amount of terpolymer latex and tutadiene latex in the first liquid (referred to as total latex)
The ratio of butadiene latex to
wt%, ratio of condensate to total latex from 2.5 to
It is appropriate to uniformly mix the three components according to a conventional method so that the amount is between 25 wt%. 3. All of the above ratios are based on solid content.

The concentration of the above-mentioned mixture (first liquid of the present invention), that is, the weight percent of the total amount of terpolymer latex, butadiene latex, and condensate in the processing agent is 10 to 50%, preferably 2.
0 to 40%, and the amount of the first liquid applied to the reinforcing fibers is suitably 12 to 25 wt%, preferably 16 to 22 wt% of the weight of the fiber as a solid content.

In addition, 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 with which the second layer is to be formed will be explained.

methacrylates or acrylates, such as zinc methacrylate, lead methacrylate, aluminum methacrylate,
It is appropriate to use silver methacrylate and suspend it in the overcoat solution. Similar metal salts of acrylic acid can also be used.

The amount of methacrylate or acrylate to be suspended in the overcoat liquid is 0.001 to 3 wt%, preferably 0.05 to 1.5 wt%.

If this amount is too small, the effect of the present invention will not be sufficient, and if this amount is too large, the effect will not increase much and it is not economical.

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 has particularly favorable results. give.

The chlorosulfonated polyethylene (C5M) 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 the 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.

Isocyanate 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 sufficient to be about 50% of that of the conventional technology, and there is no deterioration in bending fatigue or heat resistance that would occur if too much isocyanate is used, and the stability of the overcoat liquid is improved. increase

The weight percent of the total amount of isocyanate and halogen-containing polymer in the overcoat liquid may be 3 to 15 wt%, preferably 5 to 10 wt%; if this concentration is too large, the viscosity of the liquid will increase, causing unevenness. It becomes easier to do,
If this concentration is too low, the amount of adhesion will decrease and it will be difficult to obtain a sufficient effect.

Furthermore, in the present invention, adhesion is further improved by incorporating a vulcanizing agent into the overcoat liquid.

Examples of the vulcanizing agent include nitroso aromatic compounds such as p-dinitrosobenzene, tetrachlorobenzoquinone, polyp-dinitrosobenzene', p,p-dibenzoylbenzoquinone dioxime, p-benzoquinone oxime, and tetrachlorobenzene. , polyp-dinitrosobenzene, p,p-dibenzoylbenzoquinone dioxime,
Particularly preferred is p-benzoquinone dioxime.

Also, the amount of vulcanizing agent in the overcoat liquid is 0.3 to 3 wt%.
It is preferable to set it at about 0.6 to 2.5 wt%, but if this amount is too small, the effect will not be sufficient and peeling will easily occur between the first liquid layer and the second liquid layer. .

Moreover, if this amount is too large, the rubber matrix and the second liquid layer tend to separate.

A lead compound such as litharge, lead maleate, or lead phthalate can also be added to the overcoat liquid, which has the effect of improving water resistance.

The amount of lead compound in the overcoat liquid is 0.05 to 5wt.
%, preferably 1 to 3 wt%.

A first liquid and an overcoat liquid are applied to the glass fibers described above. As glass fiber, a sizing agent is added, 150
A bundle of ~500 fibers can be suitably used.

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

After applying the first liquid, preferably after sufficiently drying, an overcoat liquid is applied according to a conventional method. Drying of the first liquid is 20
It is desirable to carry out at 0 to 350°C.

The amount of overcoat liquid applied is 0.5 to 0.5 to the amount of reinforcing fiber.
A suitable amount is 5 wt%, preferably 2 to 4 wt%. Preferably at 120-200℃ after applying the second liquid
Dry in .

In addition, 2.54 cm of reinforcing fibers coated with the above-mentioned first liquid
Approximately 0.5 to 4.0 S or Z per (1 inch)
After twisting (first twist), 2 to 13 strands are further arranged and twisted in the opposite direction to the first twist (first twist) of about 0.5 to 3.0 per 2.54 cm to form a yarn. It is desirable to apply an overcoat liquid to this.

There is no particular limitation on the type of rubber to be reinforced with the reinforcing fibers to which the treatment agent of the present invention has been applied, but Hypalon, nitrile rubber, hydrogenated nitrile rubber, etc. can be exemplified, and very suitable results can be obtained, and heat resistance, Rubber products such as timing belts with good durability can be obtained.

[Function] A first layer containing a resorcin formaldehyde condensate and rubber on a core wire made of high-strength glass fiber with a diameter of 8μ or less, and a methacrylate or acrylate, an isocyanate, and a halogen-containing polymer on the first layer. By using rubber reinforcing fibers with a second layer containing Even when used under harsh conditions, it prevents deterioration over time, increases the interfacial adhesion between the RFL layer and the overcoat layer to prevent peeling, and further reduces the amount of isocyanate used. This prevents 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 Sumitomo Naugatac Co., Ltd., polypolymer content 4 J, wt%) 65 parts by weight, phthadiene latex (0700, trade name, manufactured by Nippon Synthetic Rubber, butadiene content 57 wt%) 8 parts by weight To a mixture of 15 parts by weight of an aqueous solution containing 20 wt% of an addition condensate (resol) of resorcinol and formaldehyde and 12 parts by weight of water, an emulsion of mineral oil (mineral oil content: 55 wt%) as an antiaging agent was added.
1 part by weight of aqueous ammonia (concentration 18 wt%) was added to obtain a first liquid.

0.8 parts by weight of zinc methacrylate, 6 parts by weight of chlorosulfonated polyethylene (Hypalon 40, trade name, manufactured by Showa Den Edubon Co., Ltd.), polyisocyanate (MR-20)
0, trade name, manufactured by Nippon Polyurethane Co., Ltd.) 1.1 parts by weight, p
, 1.5 parts by weight of p'-dibenzoylbenzoquinone dioxime (vulcanizing agent), and toluene were added to obtain an overcoat liquid having a concentration of 10 wt%.

Sin□58.7wt% Al20320-4wt%
Three glass fiber bundles made of 8.2 wt% Ca0 and 11-3 wt% Mg0 were arranged, and the first liquid was applied according to a conventional method (solid content 17 wt%). 250°C 1
After drying for minutes, this glass fiber bundle is 2.54cm/4
．． Give 0 twists twice (pre-twist), and then arrange 13 fiber bundles with this pre-twist to make 2.1 per 2.54 cm.
The second liquid was applied to the material that had been subjected to S twist (ply twist) twice (solid content: 3%). This was dried at 130° C. for 1 minute and used as a reinforcing fiber to prepare a test piece.

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, 2 parts by weight of vulcanizing agent, 3 parts by weight of vulcanization accelerator. 1 part, and 5 parts by weight of plasticizer.

Preparation of test piece The following test piece was prepared using rubber having the above composition.

Test specimen thickness: 1 layer, width: 10 mm, length: 500 layers of rubber sheets, sandwiching one of the above reinforcing fibers, pressing, and pressing at 160°.
Vulcanize at C for 30 minutes.

Using this test piece, after heat treatment at 120° C. for 100 hours, the test piece was bent a predetermined number of times using a bending fatigue tester at room temperature, and the residual strength of the test piece was measured.

Above test results [Residual strength corresponding to the number of bends (kgf
)) are shown in the attached table.

[Comparative Example] The same experiment as in Example 1 was conducted using 200 glass fibers made of E-glass and having a thickness of 9p instead of the glass fibers in Example 1. The results are shown in the attached table.

[Comparative Example 2] In place of the glass fiber diameter of Example 1, the same experiment was conducted using glass fibers with a diameter of 9 pots, and the results are shown in the attached table.

The numbers indicate the residual strength (Kgf) corresponding to the number of bends [
Effects of the invention - Tensile strength and bending fatigue resistance are improved.

Even when the timing belt is used for a long time under conditions where repeated bending stress is applied, the strength decreases little, and by using the rubber reinforcing glass cord of the present invention, a timing belt with a long life can be maintained.

Claims (1)

[Claims] (1) A first layer containing a resorcin formaldehyde condensate and rubber latex on a core wire made of high-strength glass fiber with a diameter of 8μ or less, and a methacrylate, acrylate, isocyanate, halogen-containing polymer and Glass cord for rubber reinforcement with a second layer containing a vulcanizing agent