JPH0443093B2 - - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention can be used as a reinforcing material for industrial rubber products such as belts such as V-belts, timing belts, and conveyor belts, various hoses, and tires. The present invention relates to an adhesion method for improving the adhesion between rubber and a fiber material made of polyester or aromatic polyamide.

(Prior Art) (Problems to be Solved by the Invention) Conventionally, in order to bond fiber materials with relatively few functional groups, such as polyesters and aromatic polyamides, to rubber, the fibers have been bonded to ordinary resorcinol. - Treatment with a dispersion of formaldehyde condensate and rubber latex alone cannot provide sufficient adhesion, and prior to treatment with the dispersion, isocyanate compounds, urea compounds, phenol derivatives, cyanuric acid derivatives, etc. are used alone or in combination. A so-called two-bath treatment has been attempted in which the dispersion is treated after treatment in the first treatment liquid. However, when using the above-mentioned pretreatment agents, solids are often handled, and it may be difficult to sufficiently disperse the treatment liquid, or it may not be possible to obtain sufficient strength for the desired adhesion. Industrially, there are still problems because expensive chemicals are used.

Attempts have also been made to coat fibers with organic solvent-based pretreatment liquids such as isocyanate or epoxy compounds in order to obtain higher adhesion, but in this case, since organic solvents are used, there is a risk of pollution and ignition and explosion. This is also not an industrially advantageous method.

There are also examples of using epoxy compounds alone or in combination with the above pretreatment agents, but when water-soluble low molecular weight epoxy compounds are used, the adhesion strength may not be sufficient, or the When an epoxy compound is used, it is difficult to dissolve it in water, or as seen in the example of the pretreatment agent, it is difficult to properly disperse water, and there are various drawbacks when implementing it industrially. It was hot.

[Structure of the invention]

(Means for solving the problem) (Function) The present invention improves the various drawbacks of the above-mentioned known methods. Heat treatment is performed after being immersed in a first treatment liquid containing a mixture with an epoxy compound having a bond, and then heat treatment is performed after being immersed in a second treatment liquid containing a resorcinol-formalin-latex mixture (hereinafter abbreviated as RFL). Then, by vulcanizing and adhering the treated fibers to rubber, strong adhesion was made possible.

The gist of the present invention is that when bonding a fiber material made of polyester or aromatic polyamide and rubber, the fiber material is treated with a first treatment solution containing a mixture of a polyepoxy compound having a hydroxyl group and an epoxy compound having an unsaturated bond. Fiber materials and rubbers, characterized in that they are immersed in water, then heat treated, then immersed in a second treatment solution containing a resorcinol-formalin-latex mixture, heat treated, and then vulcanized and bonded to rubbers. This is the adhesion method. The polyester used in the present invention is obtained by reacting one or more diols such as ethylene glycol and propylene glycol with one or more dicarboxylic acids such as terephthalic acid, isophthalic acid, and adivic acid. It is linear polyester or has a similar structure. Further, the aromatic polyamide is one composed of a condensate of aromatic diamine and terephthalic acid or isophthalic acid, or one having a structure equivalent thereto, such as fibers such as polyphenylene isophthalimide.

The epoxy mixture used in the first treatment liquid is a mixture of epoxy compounds having at least one epoxy group in one molecule.Epoxy mixtures that are particularly effective in the present invention have an average molecular weight of 250 or more.
It is a mixture of a polyepoxy compound having a hydroxyl group with an epoxy equivalent of 800 or less and an epoxy equivalent of 80 to 130, and an epoxy compound having an unsaturated bond.

Examples of the former include glycerol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitol polyglycidyl ether, etc., and mixtures thereof; examples of the latter include allyl glycidyl ether, glycidyl methacrylate, etc., and mixtures thereof. Ru.

The feature of using polyepoxy compounds with hydroxyl groups is that in addition to strengthening adhesive strength, polyepoxy compounds with hydroxyl groups are often water-soluble, which is generally a disadvantageous condition for adhesion. Another advantage is that it can be used as an aqueous solution without dispersing it in water. Further, since many of the epoxy compounds having unsaturated bonds used in the present invention are water-soluble, it is advantageous that there is no danger at all in the prior art using organic solvents.

Epoxy mixtures that are particularly useful in this invention include mixtures of sorbitol polyglycidyl ether and allyl glycidyl ether or mixtures of polyglycerol polyglycidyl ether and allyl glycidyl ether.

The mixing ratio of the polyepoxy compound having a hydroxyl group and the epoxy compound having an unsaturated bond used in the present invention is 1 to 10% of the former in terms of solid content.
Also, the concentration of these components in the first treatment liquid is 0.1 to 10% by weight in terms of solid content, preferably 0.3 to 5% by weight.
Weight%.

When using an epoxy mixture, amines, dicarboxylic acids, boron trifluoride complex compounds, and the like are often used as curing agents, among which amines are commonly used.

In the present invention, adhesive strength may be improved by using a curing agent, and in that case, amines are used, and the amount used is less than that of an epoxy compound.
The amount is 0.3 to 10 parts, preferably 0.5 to 5 parts per 100 parts by weight.

Polyester or aromatic polyamide is the first
After being immersed in the treatment liquid, heat treatment is performed, and the treatment temperature at that time is preferably 220°C or higher and 240°C or lower.

Sufficient adhesion cannot be obtained at a temperature lower than that, and use at too high a temperature is disadvantageous in terms of maintaining the strength of the fibers.

The RFL liquid consists of a resorcinol-formaldehyde condensate (hereinafter abbreviated as RF) liquid and rubber latex. RF liquid is an aqueous solution obtained by reacting a substance that easily generates formaldehyde such as formaldehyde or paraformaldehyde with a phenolic compound such as dihydroxybenzenes such as resorcinol using an appropriate known method, for example, in the presence of an alkali metal hydroxide. It is prepared using 0.5 to 4 moles of formaldehyde per mole of the phenol compound, and the resin concentration is generally adjusted to 5 to 40% by weight.

Rubber latexes include chloroprene rubber latex, styrene-butadiene copolymer rubber latex, vinylpyridine rubber latex, natural rubber latex, sulfochlorinated polypropylene rubber latex, sulfochlorinated ethylene propylene diene copolymer rubber latex, sulfochlorinated polyethylene rubber latex, etc. Examples include polyolefin latex, isoprene rubber latex, butyl rubber latex, acrylonitrile-butadiene copolymer rubber latex, and butadiene rubber latex.

Adjustment of the RFL liquid is such that the solid content of one or more of the above rubber latexes is equal to 1 solid content in the RF liquid.
The content should be 10 to 5000% by weight. Viscosity modifiers, antioxidants, etc. may be added as necessary, and adhesive strength can be improved by adding vulcanizing agents, vulcanization accelerators, etc. as described in Japanese Patent Application No. 58-208048. In some cases, it can be improved.

of fibers pretreated with epoxy mixture of polyester or aromatic polyamide to RFL fluid
Immersion in the RFL liquid can be carried out by a conventional method, but in addition to dipping, it is also possible to impregnate the fibers by coating, spraying, rolling, etc. The fiber is
After immersion in RFL liquid, dry heat treatment is performed. The heat treatment temperature varies depending on the type of fiber used, RFL composition, etc., but a temperature range of 100 to 230°C is appropriate.

It should be noted that it is also possible to mix the first treatment liquid and the second treatment liquid and perform the treatment in one stage without performing the treatment in two stages, but the adhesive strength is lower compared to the two-stage treatment method. It is often inferior in terms of

The fibers subjected to the two-stage treatment are bonded to rubber by contact vulcanization in a conventional manner. As a result, the fiber material and the rubber can be firmly bonded.
Rubbers include natural rubber, isoprene rubber, styrene-butadiene copolymer rubber, butadiene rubber, acrylonitrile-butadiene rubber, isobutylene isoprene copolymer rubber, ethylene propylene rubber, sulfochlorinated polyethylene rubber, and ethylene-propylene-ethylidene norbornene. Ethylene propylene diene copolymer rubber such as ternary copolymer rubber is used. Vulcanization adhesion with rubber is done by bonding or sandwiching the rubber with an appropriate vulcanization compound, such as mixing a vulcanizing agent, vulcanization accelerator, anti-aging agent, reinforcing agent, etc. The adhesion is completed by adding a finishing treatment to the rubber, such as vulcanization under normal vulcanization conditions, such as under pressure at 130-160° C. for several minutes to 2 hours.

Example 1 (Preparation of first treatment liquid) Polyglycidyl ether of sorbitol (manufactured by Nagase Kasei Co., Ltd., trade name: Denacol Ex-611) 1
1 part of allyl glycidyl ether (manufactured by Nagase Kasei Co., Ltd., trade name: Denacol Ex-111) was dissolved in 98 parts of water. Next, 0.02 part of tetraethylenepentamine as an epoxy curing agent was added and dissolved to form a first treatment liquid.

(Preparation of second treatment liquid) 11 g of resorcin and 16.2 g of a 37% formalin aqueous solution were added to a solution in which 0.7 g of caustic soda was dissolved in 242 g of water, and after dissolution, the solution was left to age at room temperature for 5 hours. Next, 135 g of water, 256.4 g of sulfochlorinated polyethylene latex (manufactured by Tetsutsu Kagaku Co., Ltd., trade name; CSM-450 latex: solid content 40%), vulcanization modifier (manufactured by Tetsuko Kagaku Co., Ltd., trade name; Dispon DZ-51: solid) minutes 40
% vulcanization accelerator DM33.3% zinc white 6.7%) 15.4g
were added sequentially to form an RFL solution, which was left to mature for 2 hours.

(Rubber formulation) EPDM E501A* 100 parts Zinc white 5 parts Stearic acid 1 part FEF Black 50 parts Sambar 2280 10 parts Soccinol BZ 1.0 parts Soccinol TT 1.0 parts Soccinol M 0.5 parts Sulfur 1.0 parts Mix the above composition with a Banbury mixer etc. Adjust using.

*Sumitomo Chemical Co., Ltd. Esprene (ethylene-propylene-ethylidene norbornene ternary copolymer rubber) (Measurement of adhesion) Polyester fiber cloth (manufactured by Japan Gosei Fibers Co., Ltd., product name: AKE6474 250 denier 47 pieces x 45 pieces/ 25mm)
was immersed in the first treatment solution, dried, and then heat-treated at 220°C for 5 minutes. Then, it is immersed in the second treatment liquid in the same way,
After drying, it is subjected to a so-called baking treatment at 150°C for 3 minutes.

Separately, prepare a 15 cm square mold and make a five-layer laminate of rubber - treated fiber - rubber - treated fiber - rubber between the second treated fiber layer and the third rubber layer. A release paper is placed at the tip of the test piece so that the end of the test piece is exposed so that it can be easily held in the tester when measuring peel strength. Then, it was heated at 150℃ under a surface pressure of 30Kg/ ^cm2 for 30 minutes.
Heat for minutes, rubber vulcanization and gluing.

An adhesive test piece was cut to a width of 25 mm, and the peel strength was measured by pulling it 180 degrees in the opposite direction from where the release paper was sandwiched. The adhesive strength was 25.6Kgf/25mm, indicating rubber breakage.

Comparative Example 1 The same treatment as in Example 1 was performed except that immersion in the first treatment liquid was not performed, and the adhesive strength was measured.

The adhesive force was 2.0 kgf/25 mm, and the peeled surface was completely at the interface between the fiber and the rubber.

Example 2 Aromatic polyamide fiber cloth (manufactured by Asahi Schubel Co., Ltd., trade name: 713/
Adhesion was carried out in the same manner as in Example 1, except that 501000 denier 31 pieces x 31 pieces/25 mm) was used, and the adhesive strength was 12.7.
Kgf/25mm was obtained. The peeling surface was mainly due to interfacial peeling between the RFL treated layer and the rubber compound, but some rubber fractures were also observed.

Comparative Example 2 The same treatment as in Example 2 was performed, except that immersion in the first treatment liquid was not performed, and the adhesive strength was measured.

The adhesive force was 2.2 kgf/25 mm, and the peeled surface was completely at the fiber-rubber interface.

Example 3 (Preparation of first treatment liquid) Diglycerol polyglycidyl ether (manufactured by Nagase Kasei Co., Ltd., trade name: Denacol EX-421) 1
Polyglycerol polyglycidyl ether (manufactured by Nagase Kasei Co., Ltd., trade name: Denacol EX-512)
1 part and 0.5 part of glycidyl methacrylate (manufactured by NOF Corporation, trade name: Blenmar G) are dissolved in 97.5 parts of water. Next, 0.02 part of tetraethylenepentamine was added as an epoxy curing agent and dissolved to form a first treatment liquid.

(Preparation of second treatment solution) 11 g of resorcinol and 16.2 g of a 37% formalin aqueous solution were added to a solution in which 0.4 g of caustic soda was dissolved in 242 g of water, and after dissolution, the solution was left to age at room temperature for 5 hours. Then water
220.4g, natural rubber latex (manufactured by Nomura Trading Co., Ltd.)
Product name: SOCTEX Latex-HA: solid content 60%)
171g was added one after another and left to mature as an RFL liquid for 2 hours.

(Rubber composition) Natural rubber 100 parts Zinc white 6 parts ISAF black 40 parts Stearic acid 4 parts Soccinol M 0.5 parts Sulfur 3.5 parts The above composition is prepared using a Banbury mixer or the like.

(Measurement of adhesive strength) Polyester fiber cloth (manufactured by Nippon Gosei Fibers Co., Ltd., product name: AKE6474 250 denier 47 pieces x 45 pieces/25 mm)
was immersed in the first treatment solution, dried, and then heat-treated at 225°C for 5 minutes. Then, it is immersed in the second treatment liquid in the same way,
After drying, it is subjected to a so-called baking treatment at 150°C for 3 minutes. After that, adhesive was applied in the same manner as in Example 1, and the adhesive strength was 18.6.
Kgf/25mm was obtained. The rubber broke.

Example 4 Aromatic polyamide fiber cloth (manufactured by Asahi Schubel Co., Ltd., trade name: 713/
501,000 denier 31 pieces x 31 pieces/25mm) was used for bonding in the same manner as in Example 3, and the adhesive strength was 13.4Kgf/
I got 25mm. The peeled surface is mainly due to rubber breakage and some RFL.
There was also interfacial peeling between the treated layer and the rubber compound.

(Effects of the Invention) According to the present invention, it is possible to strengthen the adhesive force between fiber materials made of polyester or aromatic polyamide and rubber, which has been considered difficult in the past. It is now possible to make it usable as a.

Claims (1)

[Claims] 1. When bonding a fiber material made of polyester or aromatic polyamide to rubber, the fiber material is bonded to a first material containing a mixture of a polyepoxy compound having a hydroxyl group and an epoxy compound having an unsaturated bond. Fiber materials and rubbers, characterized in that they are immersed in a treatment solution, then heat treated, then immersed in a second treatment solution containing a resorcinol-formalin-latex mixture, then heat treated, and then vulcanized and bonded to rubbers. Adhesion method. 2. The method according to claim 1, wherein the polyepoxy compound having a hydroxyl group is sorbitol polyglycidyl ether. 3. The method according to claim 1, wherein the polyepoxy compound having a hydroxyl group is polyglycerol polyglycidyl ether. 4. The method according to claim 1, wherein the epoxy compound containing an unsaturated bond is allyl glycidyl ether. 5. The method according to claim 1, wherein the temperature at which the heat treatment is performed after immersion in the first treatment liquid is 220°C or more and 240°C or less. 6. The method according to claim 1, wherein the latex is a sulfochlorinated polyolefin latex. 7. The method according to claim 1, wherein the rubber is ethylene propylene diene copolymer rubber.