JPH11240308A - Rubber reinforcing cord and treatment agent thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a treatment agent which makes up a reinforcing cord and its coated layer firmly bonded to mixed rubber consisting of hydro-nitrile rubber excellent in flexibility and heat resistance, and another hydro-nitrile rubber dispersed with zinc methacrylate. SOLUTION: A treatment agent containing a resorcinol-formalin condensate and rubber latex is applied on a fiber for rubber reinforcement and dried and hardened into a first coated layer, and further another treatment agent using a rubber compound, a vulcanizing agent and a silane coupling agent as the main components is applied on the first coated layer, drying and hardening it, and thereby a second coated layer is formed up.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrogenated nitrile rubber (hereinafter referred to as "H-NBR") having excellent bending resistance and heat resistance and a hydrogenated nitrile rubber (hereinafter referred to as "H-NBR") having zinc methacrylate dispersed therein. NBR / ZDMA) and a rubber reinforcing cord used for reinforcing mixed rubber.

[0002]

2. Description of the Related Art In order to improve the strength and durability of rubber products such as rubber belts and rubber tires, it is widely practiced to embed glass fibers, chemical fibers and the like as reinforcing fibers in rubber.

However, since the reinforcing fibers themselves generally have poor affinity with rubber and have poor adhesiveness, when the surface of the reinforcing fibers is embedded in rubber without processing, the reinforcing fibers do not adhere to the rubber. Adhesion is weak and easily peels off during use. In such a state, the reinforcing fiber cannot satisfy the performance required as a reinforcing material for rubber products.

[0004] Therefore, when various reinforcing fibers are used in rubber products, it is widely and widely practiced to form a coating layer on the surface of the reinforcing fibers to improve the familiarity with the rubber used and to improve the adhesiveness. I have.

[0005] For example, a glass fiber cord (JP-A-63-270877) having a coating formed by applying a mixed treatment of a resorcin-formalin condensate and H-NBR latex to a glass fiber and drying and curing the glass fiber is exemplified. . Further, a rubber reinforcing fiber in which a halogen-containing polymer and an isocyanate are applied to the second layer and a third layer containing the same rubber as the matrix rubber is formed has been proposed (Japanese Patent Publication No. 5-71710). However, the former cannot obtain sufficient adhesive strength with rubber mixed with H-NBR and H-NBR / ZDMA, and the latter requires three layers of coating, which complicates the production process and increases the cost.

[0006]

As described above, forming a coating layer on the surface of a reinforcing fiber is widely and generally performed in order to improve the adhesion between the rubber used and the reinforcing fiber. However, there are a wide variety of types of rubber and reinforcing fibers currently used, and if the types of rubber and reinforcing fibers are different, the types of coating layers for improving the adhesiveness are naturally different.

[0007] In recent years, H-NBR / ZDMA rubber has been receiving attention in various fields. Rubber mixed with H-NBR / ZDMA rubber and H-NBR rubber has higher heat resistance than H-NBR rubber which has been conventionally used.
It can be used in areas where it could not be used before, or as a higher performance alternative.

[0008] The present invention relates to H-NBR and H-NBR / ZD.
When a reinforcing fiber is used for a rubber containing MA as a main component, a reinforcing cord having improved adhesion to the rubber and a coating layer of the reinforcing cord (surface treatment of the second layer on the reinforcing fiber) The purpose of the present invention is to obtain a treatment agent for forming a film.

[0009]

According to a first aspect of the present invention, there is provided a rubber reinforcing cord according to the present invention, wherein the rubber reinforcing fiber comprises a resorcinol-formalin condensate and a rubber latex in a rubber reinforcing fiber. Is applied and dried and cured to form a first coating layer. In the rubber reinforcing fiber cord having a second coating layer formed by applying a different treatment agent on the first coating layer and drying and curing the second coating layer, the second coating layer Treatment agent for
It is mainly composed of a rubber compound, a vulcanizing agent and a silane coupling agent.

[0010] In the rubber reinforcing cord according to the second aspect of the present invention, the silane coupling agent contained in the treating agent for the second coating layer is vinyltris (β-methoxyethoxy) silane. It is something that is.

According to a third aspect of the present invention, there is provided the rubber reinforcing cord according to the first or second aspect, wherein the rubber compound contained in the treating agent for the second coating layer comprises a hydrogenated nitrile rubber and zinc methacrylate. And a hydrogenated nitrile rubber in which is dispersed a mixed rubber.

[0012] The treatment agent of the invention according to claim 4 is the treatment agent for the second coating layer according to any one of claims 1 to 3.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The inventor of the present invention has conducted intensive studies to solve the above-mentioned problems, and as a result, a rubber compound,
By using a coating layer treating agent containing a vulcanizing agent and a silane coupling agent, H-NBR and H-NBR can be obtained.
It has been found that the adhesion between the rubber containing / ZDMA as a main component and the reinforcing cord can be dramatically improved. Hereinafter, embodiments of the present invention will be described in detail.

The rubber reinforcing fiber used in the present invention is not limited, and specific examples thereof include glass fiber, polyvinyl alcohol fiber represented by vinylon fiber, polyester fiber, polyamide fiber such as nylon and aramid (aromatic polyamide). , Carbon fiber, polyparaphenylene benzoxazole fiber and the like. Among these, glass fibers and aramid fibers are preferably used. The type of glass fiber is not particularly limited, and examples thereof include non-alkali glass and high-strength glass.
The filament diameter of the glass fiber is not particularly limited, but those having a diameter of 5 to 13 μm are generally used. As the aramid fiber, those having a denier of 500 to 5,000 are generally used. Examples of the form of these fibers include stable, filament, cord, rope, and canvas.

The rubber latex forming the first coating layer according to claim 1 is specifically a butadiene / styrene copolymer latex, a dicarboxylated butadiene / styrene copolymer latex, a vinylpyridine / butadiene / styrene. Terpolymer latex, chloroprene latex, butadiene rubber latex, chlorosulfonated polyethylene latex, acrylonitrile / butadiene copolymer latex, and nitrile group-containing highly saturated copolymer rubber latex are preferred.

The rubber compound contained in the treating agent for the second coating layer may be any one of various types depending on the type of the matrix rubber.
Alternatively, a plurality of mixed rubbers can be used. The type of rubber and its solvent are not particularly limited, but chloroprene rubber, chlorosulfonated polyethylene, H-NBR, H-NBR / ZDMA, etc. are used as the rubber. These rubbers are selected depending on the type of the matrix rubber in consideration of the compatibility and the like. Particularly, when the matrix rubber is a mixed rubber of H-NBR and H-NBR / ZDMA, the rubber in the second coating agent is used. As the compound, one obtained by dissolving the same rubber is suitably used.

H-NBR and H-NBR / ZD to be dissolved
The weight ratio to MA is H-NBR / (H-NBR / ZDM).
A) = 45 to 80/55 to 20, preferably H-NBR
If the ratio of / ZDMA is small, sufficient adhesive strength cannot be obtained, and if the ratio is large, the cord becomes hard and the bending fatigue property deteriorates.

The H-NBR must have an iodine value of 120 or less from the viewpoint of the film strength of the rubber and the adhesiveness to the matrix rubber, and preferably has an iodine value of 0 to 100. Zetpol (trade name, manufactured by Zeon Corporation) can be suitably used as this rubber. The iodine value is a value determined according to JIS K0070.

As the H-NBR / ZDMA in the present invention, ZSC (trade name, manufactured by Nippon Zeon Co., Ltd.) in which polyzinc methacrylate is dispersed in the above-mentioned zetpol can be suitably used.

As a solvent for dissolving the rubber, aromatic hydrocarbons such as benzene, toluene or xylene, halogenated hydrocarbons such as trichloroethylene, methyl ethyl ketone (hereinafter referred to as MEK), ethyl acetate and the like are used. In the case of a compounded rubber such as the aforementioned H-NBR, MEK is usually used.

The vulcanizing agent contained in the treatment agent for the second coating layer includes:
Organic peroxides such as sulfur, dicumyl peroxide, and 1,3-bis (t-butylperoxy-isopropyl) benzene; and aromatic nitroso compounds such as p-dinitrosonaphthalene and p-dinitrosobenzene. . Many of these may be preliminarily compounded in the rubber compound, and are added when necessary.

The type of the silane coupling agent described in the item 1 is not particularly limited, but specific examples thereof include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, and γ-glycidoxypropyl. Trimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N -β- (aminoethyl) -γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N
-Phenyl-γ-aminopropyltrimethoxysilane or γ-mercaptopropyltrimethoxysilane can be used. In particular, the vinyl tris (β-methoxyethoxy) silane described in claim 2 can be suitably used for improving the adhesiveness.

The compounding ratio of the coating layer treating agent is as follows: rubber compound / vulcanizing agent / silane coupling agent = 100 / 0-10
/ 1 to 150 parts by weight, and 100/0 to 6/3
It can be suitably used in the range of 0 to 80 parts by weight.

The treating agent for the second coating layer of the present invention may contain an inorganic filler such as carbon black, a plasticizer, an antioxidant, and a crosslinking assistant.

The treating agent for the second coating layer of the glass fiber of the present invention is usually prepared as a solution or dispersion having a solid content of 3 to 25% by weight, more preferably 5 to 15% by weight.

The method for forming the second coating layer is not particularly limited, but usually, the rubber reinforcing fiber provided with the primary coating layer is immersed in a solvent tank containing the treating agent for the second coating layer, and then dried. Let go through the furnace to form a coating layer. The drying conditions are not limited, but the drying is generally performed at 80 to 160 ° C. for 0.1 to 1 minute. The adhesion rate is 1 to 10%, preferably 3 to 7%.

[0027]

[Example 1] Glass fiber (E-glass; 9 μm)
The glass filaments having a diameter of 200 were bundled together, and the first coating layer treating agent shown in Table 1 below was applied by a known method.

[0028]

[Table 1] ---------------------------------------------- --------------------- Composition Blended amount (parts by weight) ------------------------------------ −−−−−−−−−− Vinylpyridine latex (solid content 40%) 45 Chlorosulfonated polyethylene latex (solid content 40%) 20 Resorcin / formalin condensate (solid content 8%) 30 (resorcin / formalin = (1 / 1.3 molar ratio) 25% ammonia water 1 water 4 ----------------------------------- --------------------------------

The glass fiber on which the first coating layer is formed is 8
After the twist / 10 cm priming, 11 strands are aligned and further twisted 8 times / 10 cm, and then the second coating layer treating agent is applied and dried and cured in the same manner as described above, and the glass fiber Was the code.

[0030]

[Table 2] ---------------------------------------------- ------------- Composition Compounding ratio (parts by weight) --------------------------------------------- Rubber Composition 100 Toluene 416 Methyl ethyl ketone 180 Vinyl tris (β-methoxyethoxy) silane 50 ---------------------------------- -------------------------

The second coating layer was 5% by weight based on the weight of the glass fiber cord. The above rubber composition is shown in Table 3 below.

[0032]

[Table 3] ---------------------------------------------- --------- Rubber composition compounding ratio (parts by weight) ------------------------------------------------------------ 70 ZSC2000L (* 2) 30 ZnO 10 Stearic acid 1 Carbon black 30 TOTM (Trioctyl Trimellitate) 5 Sulfur 0.1 1,3-Bis- (t-btylperoxy-isopropyl) -benzene 6 --------- ---------------------------------------------- (* 1) Brand name H-NBR: manufactured by Zeon Corporation (* 2) Brand name H-NBR / ZMDA: manufactured by Zeon Corporation

In order to test the adhesion between the rubber mixture of H-NBR and H-NBR / ZMDA and the above-mentioned rubber reinforcing cord, a test piece having the composition shown in Table 3 (width 25 mm × length 50 mm)
× thickness 5 mm), the glass fiber cords were arranged along the long side, and heated at 160 ° C. for 30 minutes for bonding.

The test piece after the heat bonding was applied to a tensile tester and pulled in the fiber direction to measure the strength value.
The results are shown in Table 5 below.

Example 2 An aramid fiber (Technola T202: 1500d manufactured by Teijin Limited) was used in place of the glass fiber used in Example 1, and the same treatment for the first coating layer as in Example 1 was applied. The solid content was adjusted to be 12%, and heat treatment was performed at 250 ° C. for 1 minute. This was plied twice and subjected to 3.1 times of twist per inch to obtain an aramid fiber cord. Using the aramid fiber cord thus obtained, a treatment was performed using the same treating agent for the second coating layer as in Example 1. The second coating layer was 10% by weight based on the weight of the aramid fiber cord. The evaluation method of the adhesiveness was the same as in Example 1.

Comparative Example 1 The second example used in Example 1 was used.
The second coating layer was formed using the processing agents shown in Table 4 below in place of the coating layer processing agents (described in Table 2). Otherwise, the test was performed under the same conditions as in Example 1.

[0037]

[Table 4] ------------------------------------------ For comparative coating layer Treatment agent Compounding ratio (parts by weight) Rubber composition 100 Toluene 416 Methyl ethyl ketone 180 ------------- -----------------------------

Comparative Example 2 A second coating layer was formed in Example 2 by using the treating agent shown in Table 4 used in Comparative Example 1 instead of the treating agent for the second coating layer used. . Otherwise, the test was performed under the same conditions as in Example 2.

[0039]

[Table 5]

[0040]

According to the present invention, H is excellent in bending resistance and heat resistance.
-Dramatically improved adhesion between NBR and H-NBR / ZDMA compounded rubber and glass fiber, and the use of the glass fiber cord according to the present invention makes it possible to use in a high temperature environment and to be durable. An H-NBR rubber product having greatly improved properties can be obtained.

Claims (4)

[Claims] 1. A treatment agent containing a resorcinol-formalin condensate and rubber latex is applied to a rubber reinforcing fiber, dried and cured to form a first coating layer, and a different treatment agent is further applied on the first coating layer and dried. In a rubber reinforcing fiber cord having a second coating layer formed by curing, a treating agent for the second coating layer is mainly composed of a rubber compound, a vulcanizing agent and a silane coupling agent. Cord for rubber reinforcement. 2. The rubber reinforcing cord according to claim 1, wherein the silane coupling agent contained in the treatment agent for the second coating layer is vinyltris (β-methoxyethoxy) silane. 3. The rubber compound contained in the second coating layer treating agent is a melt of a mixed rubber comprising a hydrogenated nitrile rubber and a hydrogenated nitrile rubber in which zinc methacrylate is dispersed. Or the rubber reinforcing cord according to 2. 4. The treating agent for a second coating layer according to claim 1, wherein