JPH01304168A - Method of bonding rubber compound to fiber - Google Patents

Abstract

PURPOSE:To improve the adhesion by treating fibers with a polyepoxy compound and a specified 1,2-polybutadiene, joining the treated fibers and an unvulcanized rubber compound containing an organic peroxide, and effecting vulcanization. CONSTITUTION:A polyepoxy compound (a) having at least two epoxy groups in the molecule and a 1,2-polybutadiene (b) having at least two COOH or OH groups in the molecule in an amount sufficient to provide a molar ratio of the epoxy groups of component (a) to the COOH or OH groups of component (b) of 1-4:4-1 are dissolved in a solvent (c) to give a treating solution. Fibers are treated by immersing them in this treating solution at 160-250 deg.C for several minutes after, if required, pretreatment by immersing them in a solution containing a polyisocyanate compound or polyepoxy compound at 160-250 deg.C for several minute, thus giving fibers treated with components (a) and (b). The treated fibers and a rubber compound containing an organic peroxide (e.g., dicumyl peroxide) in an amount of at least 0.0005mol per 100g of rubber are joined, and vulcanization is effected.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of adhering a rubber compound to fibers, and more particularly to a method of strongly adhering highly saturated or fully saturated rubber to fibers.

In recent years, for example, in the technical field of automobiles, the performance of engines has significantly improved, and as a result, the ambient temperature around the engine has increased significantly compared to before. Therefore, rubbers whose main chains are highly saturated or completely saturated, such as hydrogenated nitrile rubber, chlorosulfonated polyethylene rubber, and fluororubber, which have excellent heat resistance, are used as power transmission belts, etc. around the engine. The use of rubber is being considered, and various methods of bonding such rubber and fibers have already been proposed.

Generally, the conventional method for adhering rubber and fibers is to treat the fibers with a mixture of resorcinol-formalin resin and rubber latex called RFL liquid, and then vulcanize this in close contact with unvulcanized rubber. . Therefore, for example, regarding adhesion between hydrogenated nitrile rubber and fibers,
As described in JP-A-24131 and JP-A-61-207442, a method of treating fibers with an RFL liquid consisting of carboxylated NBR latex or halogen-containing polymer latex has been proposed, and chlorosulfonated polyethylene rubber and fibers, JP-A-61-127
RFL made of NBR latex or carboxylated NBR latex, as described in Publication No. 739.
A method of treating with liquid has been proposed. Regarding adhesion between fluororubber and fibers, Japanese Patent Application Laid-Open No. 58-11131
As described in the above publication, a method of processing with an RFL liquid made of NBR latex or acrylate latex has been proposed.

However, in bonding rubber and fibers using RFL liquid, in order to achieve excellent adhesion, it is necessary to use the same type of rubber latex as the rubber in the rubber compound from the viewpoint of compatibility. .

None of the above-mentioned methods can achieve strong adhesion between the rubber and the fibers because the rubber and the latex in the RFL liquid are of different rubber types.

As a result of intensive research in order to solve the above-mentioned problems in adhesion between rubber compounds and fibers, the inventors of the present invention discovered that a polyepoxy compound having two or more epoxy groups in the molecule. 1,2- having two or more carboxyl groups or hydroxyl groups in the molecule
After treating the fibers with polybutadiene, the fibers are closely vulcanized with an unvulcanized rubber compound containing an organic peroxide to produce not only natural rubber but also synthetic rubber, especially the aforementioned hydrogenated nitrile rubber and chlorosulfonated polyethylene. The present invention was achieved by discovering that strong adhesion with fibers can also be achieved with highly saturated or fully saturated rubbers such as rubber and fluororubber.

The present invention is directed to a method for adhering a rubber compound to fibers, and the present invention is directed to a method for adhering a rubber compound to fibers. Yama) The fiber is treated with 1,2-polybutadiene having two or more carboxyl groups or hydroxyl groups in the molecule, and then vulcanized in close contact with an unvulcanized rubber compound containing an organic peroxide. .

In the method of the present invention, polyepoxy compounds having two or more epoxy groups in the molecule include polyhydric alcohols such as ethylene glycol, glycerin, sorbitol, and pentaerythritol, polyalkylene glycols such as polyethylene glycol, and epichlorohydrin. Reaction products with halogen-containing epoxy compounds, polyhydric phenols such as resorcinol, bis(4-hydroxyphenyl) dimethylethane, phenol/formamide resin, resorcinol/formamide resin, phenol lFM fat, and halogen-containing epoxy such as epichlorohydrin. Reaction products with compounds are preferably used.

In addition, the 1,2-polybutadiene used in the method of the present invention is not particularly limited as long as it has two or more carboxyl groups or hydroxyl groups in the molecule, but it usually has 1,2-polybutadiene.
．． 2-Bound amount is 50% or more, molecular weight is 500-5000
It is preferable to use one with a certain degree. As such 1,2-polybutadiene, commercially available products can be used.

In the method of the present invention, the above polyepoxy compound and 1
．． 2-polybutadiene is usually made into a solution containing it, and the fibers are treated by immersing them in the solution. In such a treatment liquid, a polyepoxy compound and 1.2
- The blending ratio of polybutadiene is the number of moles of epoxy groups in the polyepoxy compound/the number of moles of carboxyl groups or hydroxyl groups in 1,2-polybutadiene in the range of 1/4 to 4/1, preferably 2/1 to 1/2. It is. When the blending ratio of the polyepoxy compound and 1,2-polybutadiene in the treatment liquid is outside the above range, strong adhesion between the rubber and the fibers cannot be obtained.

In this manner, after the fibers are immersed in a solution containing a polyepoxy compound and 1,2-polybutadiene, the fibers are heat-treated. This heat treatment may be performed at a temperature sufficient to react and fix the epoxy compound and 1,2-polybutadiene attached to the fiber, although it depends on the type of fiber used, and is usually treated at 160 to 250°C for several minutes. do it.

In the above treatment, when an isocyanate compound or a blocked polyisocyanate compound is used instead of a polyepoxy compound, the reactivity with the unsaturated dicarboxylic acid or its anhydride is too high, and the pot life of the treatment liquid is short.
Poor practicality.

However, in the method of the present invention, the fibers are pretreated with a polyisocyanate compound or a polyepoxy compound, and then treated with the polyepoxy compound and an unsaturated dicarboxylic acid or its anhydride. A stronger adhesion can be achieved between the two. In particular, this pretreatment is effective in achieving stronger adhesion between surface inert fibers and rubber, such as aromatic polyamide fibers or polyester fibers.

As the isocyanate compound used in this pretreatment, for example, polyisocyanates such as tolylene diisocyanate, metaphenylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and polymethylene polyphenyl diisocyanate are preferably used. In addition, polyhydric alcohol-added polyisocyanates obtained by reacting such polyisocyanates with compounds having two or more active hydrogens in the molecule, such as trimethylolpropane and pentaerythritol, and polyisocyanates with phenols and tertiary Blocked polyisocyanates, in which isocyanate groups of polyisocyanates are blocked by reacting blocking agents such as alcohols and secondary amines, are also suitably used as polyisocyanate compounds.

In addition, as described above, the polyepoxy compound used in the pretreatment is obtained by reacting polyhydric alcohol, polyalkylene glycol, polyhydric phenol, phenol resin, etc. with a halogen-containing epoxy compound such as epichlorohydrin. Polyepoxy compounds are preferably used.

In this way, pretreatment of fibers with polyisocyanate compounds or epoxy compounds is also carried out by using a solution containing these polyisocyanate compounds or polyepoxy compounds, immersing the fibers in such a solution, and then heat-treating the fibers. It will be done. The heat treatment in this pretreatment also depends on the type of fiber used, but it may be carried out at a temperature sufficient to react and fix the polyisocyanate compound or polyepoxy compound attached to the fiber, and is usually 16
What is necessary is just to process at 0-250 degreeC for several minutes.

In the method of the present invention, as described above, preferably,
After the fibers are pretreated with a polyisocyanate compound or a polyepoxy compound, they are treated with a polyepoxy compound and an unsaturated dicarboxylic acid or its anhydride, and then adhered to an unvulcanized rubber compound containing an organic peroxide. By vulcanization, strong adhesion can be achieved between the rubber compound and the fibers. However, in the present invention, the conditions for vulcanization adhesion are not particularly limited, and may be any conventional conditions known for each rubber compound.

In the method of the present invention, the fibers typically include cotton, polyvinyl alcohol fibers, aliphatic and aromatic polyamide fibers, polyester fibers, carbon fibers, glass fibers, etc., but there are no particular limitations. Rather, it includes all fibers traditionally used for bonding with rubber.

Further, the rubber to which the method of the present invention can be applied may be either natural rubber or synthetic rubber as long as it can be crosslinked with organic peroxide, and is not particularly limited. , in the method of the present invention, the rubber is
Natural rubber, butadiene rubber, isoprene rubber, styrene-butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber, ethylene-propylene copolymer rubber, chlorosulfonated polyethylene rubber, hydrated nitrile rubber, urethane rubber, silicone rubber, Examples include fluororubber.

The above organic peroxide is not particularly limited and may be any conventionally known one, such as di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide, etc. oxide, α, α”-bis(t-butylperoxy)-p-diisopropylbenzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyldi(t-butyl peroxy)hexyne-3,2,5-dimethyl-2,5-
Di(benzoylperoxy)hexane, t-butylperoxyisopropyl carbonate, 1,1-bis(t-
butylperoxy)-3,5,5-trimethylcyclohexane and the like.

The amount of organic peroxide blended in the unvulcanized rubber compound is at least 0.00 s mol, preferably at least 0.00 mol, per 100 g of rubber. When the amount of organic peroxide added to the rubber is less than 0.0005 mol per 100 g of rubber, strong adhesion between the rubber compound and the fibers cannot be obtained. However, if the amount of organic peroxide in the rubber compound is too large, the resulting vulcanized rubber may have poor practical physical properties, such as reduced elongation or excessive hardness. In the present invention, the amount of organic peroxide in the unvulcanized rubber compound is usually 0.0 g per 100 g of rubber.
It is 5 mol or less, preferably 0.02 mol or less.

In the method of the present invention, the rubber compound contains, in addition to the above-mentioned organic peroxides, vulcanizing agents such as sulfur and triazines,
Thiazoles, dithiocarbamates, thiurams,
It may contain a vulcanization accelerator such as thioureas. Furthermore, it may contain appropriate amounts of various reinforcing fillers, anti-aging agents, plasticizers, vulcanization aids, processing aids, etc. that are commonly known as rubber compounds.

According to the method of the present invention, fibers are treated with an epoxy compound having two or more epoxy groups in the molecule and 1゜2-polybutadiene, and the fibers are treated with an organic peroxide containing organic peroxide. By vulcanizing in close contact with the unvulcanized rubber compound,
Strong adhesion can be obtained between the rubber compound and the fibers.

In the method of the present invention, although not limited by the adhesion mechanism, epoxy groups are imparted to the fibers by treatment with an epoxy compound and 1,2-polybutadiene, either through or without the epoxy groups. The 1,2-polybutadiene is fixed to the fibers, thus
l applied to the fibers.

Since carbon-carbon double bonds with high radical reactivity derived from 2-polybutadiene are imparted, when the fiber is closely vulcanized with an unvulcanized rubber compound containing an organic peroxide, the organic peroxide It is thought that radicals are generated in the rubber, and these radicals mutually bond with the carbon-carbon double bonds on the fibers, thereby firmly adhering the rubber and the fibers.

Implementation (2) The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples in any way.

Example 1 1260 D/m was added to each of the treatment solutions A-D shown in Table 1.
After soaking 2 x 4 nylon 6 fiber cord, 18
Heat treatment was performed at 0°C for 2 minutes. Next, the sheets of unvulcanized rubber compounds 1 to 3 having the compositions shown in Table 2 were brought into close contact with each other, and then vulcanized at 160 DEG C. for 20 minutes to obtain an adhesive.

Table 2 (Note) 1) Parts by weight 2) Zetpol 2020 manufactured by Nippon Zeon ■ Regarding this adhesive, the 180° peel adhesive force between the fiber cord and the rubber was measured using a peel tester at a peel rate of 1100 t/min. . The results are shown in Table 3.

Table 3 (Note) The numbers in parentheses indicate the state of adhesive failure, R indicates rubber failure, and RA indicates adhesive-rubber interface failure. The same applies hereafter.

Example 2 1500D was added to each of pretreatment liquids a and b shown in Table 4.
/2×3 aromatic polyamide fiber cord (Tektora, manufactured by Kijin ■) was immersed, then heat treated at 210°C for 1 minute, then immersed in treatment solution A shown in Table 1, and heat treated at 230°C for 1 minute.

Thereafter, this treated cord was brought into close contact with a sheet of unvulcanized rubber compound 1 shown in Table 2, and then vulcanized at 160° C. for 20 minutes to obtain an adhesive.

Table 4 (Note) 1) Polyisocyanate manufactured by Kasei Upjohn ■ This adhesive was tested at a peeling speed of 1100 using a peel tester.
The 180° peel adhesion between the fiber cord and the rubber was measured at f/min. The results are shown in Table 5.

For comparison, except that no pretreatment was applied to the fiber cord,
After treating the fiber cord with treatment liquid A in the same manner as above, it was brought into close contact with a sheet of unvulcanized rubber compound 1 shown in Table 2, and vulcanized at 160°C for 20 minutes to obtain an adhesive. Ta. This adhesive was tested at a peeling speed of 100mm/100mm using a peeling tester.
The 180° peel adhesion between the fiber cord and the rubber was measured in minutes.

The results are also shown in Table 5.

Table 5 By pretreating the fiber cord with an epoxy compound or an isocyanate compound according to the present invention, the fiber cord can be bonded more strongly to rubber.

Example 3 A 1100D/2X5 polyester fiber cord was immersed in treatment liquid a shown in Table 4, then heat treated at 210°C for 1 minute, and then this fiber cord was immersed in treatment liquid A shown in Table 1 and as a comparative example. 230 Table 6 (Note) 1) Carboxylated NBR latex manufactured by Nippon Zeon ■ 2) Rollosulfonated polyethylene latte manufactured by Seitetsu Kagaku Kogyo ■, Tsukusu 3) Vinylpyridine-3BR latex manufactured by Japan Synthetic Rubber ■ was heat treated at ℃ for 1 minute. In this way, the treated fiber cord was treated with unvulcanized rubber having the composition shown in Table 7 Table 7 (Note) 1) Part by weight 2) Hypalon 453 manufactured by Showa Denko/Dupont ■ Daiel G301 compound manufactured by Daikin Industries ■ After adhering to sheets 4 and 5, they were vulcanized at 160°C for 20 minutes,
Obtained adhesive.

The adhesive strength of this adhesive was measured in the same manner as in Example 1. The results are shown in Table 8. According to the method shown in Table 8 of the present invention, polyester fiber cords were also able to be firmly adhered to the rubber compound.

However, sufficient adhesion could not be obtained by RFL treatment.

Claims (2)

[Claims] (1) In the method of adhering a rubber compound and fibers, (a)
After treating the fiber with an epoxy compound having two or more epoxy groups in the molecule and (b) 1,2-polybutadiene having two or more carboxyl or hydroxyl groups in the molecule, unprocessed fibers containing an organic peroxide are treated. A method for adhering a rubber compound and fiber, characterized by vulcanization in close contact with the sulfur rubber compound. (2) In the method of bonding a rubber compound and fibers, the fibers are treated with an isocyanate compound or an epoxy compound,
Next, after treating the fibers with (a) an epoxy compound having two or more epoxy groups in the molecule and (b) 1,2-polybutadiene having two or more carboxyl or hydroxyl groups in the molecule, the fibers are treated with an organic peroxide. A method for adhering a rubber compound and fibers, the method comprising closely vulcanizing a rubber compound and a fiber containing an unvulcanized rubber compound.