JPH11323738A - Aromatic polyamide fiber for reinforcing rubber, its production and rubber composite material reinforced with fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aromatic polyamide fiber having excellent adhesion to various kinds of rubbers, especially chlorinated polyethylene rubbers, and used for reinforcing the rubbers, to provide a method for producing the same, and to provide a rubber composite material reinforced with the fibers, having excellent adhesion between the fibers and the rubber, having excellent flexibility, weather resistance and flame retardancy, stable against alkalis, alcohols and acids excluding concentrated nitric acid, and being lightweight. SOLUTION: This aromatic polyamide fiber for reinforcing rubbers is obtained by treating the surface of an aromatic polyamide fiber with the first treating solution containing a vinyl chloride copolymer latex, and subsequently treating the treated fiber with the second treating solution containing a composition comprising 100 pts.wt. (solid content) of the mixture of a rubber latex with a resorcinol-formaldehyde precondensate, and 5-15 pts.wt. of a blocked isocyanate compound or an ethylenimine compound. A chlorinated polyethylene rubber is reinforced with the obtained aromatic polyamide fibers for reinforcing the rubbers, and is processed in the form of tires, belts, hoses, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aromatic polyamide fiber for rubber reinforcement having excellent adhesion to various rubbers, especially chlorinated polyethylene rubber, a method for producing the same, and adhesion, flexibility and weather resistance between the fiber and rubber. The present invention relates to a fiber-reinforced rubber composite material which is excellent in heat resistance and flame retardancy, is stable to acids, alkalis and alcohols except concentrated nitric acid, and is lightweight.

[0002]

2. Description of the Related Art Aromatic polyamide fibers have high strength, high modulus, and excellent heat resistance of the fibers themselves.
Widely used as rubber reinforcing fibers in fiber reinforced rubber composite materials such as belts and hoses.

However, aromatic polyamide fibers are:
Compared to aliphatic polyamide fibers and polyester fibers,
Due to poor adhesion to rubber, various methods for improving the adhesion between aromatic polyamide fibers and rubber have been conventionally proposed.

For example, JP-A-2-202569 discloses that an aromatic polyamide fiber is treated with an epoxy compound having two or more epoxy groups in one molecule, and then a resorcinol-formaldehyde rubber latex mixture (RF
L).

[0005] Also, Japanese Patent Application Laid-Open No. Hei 3-40875 discloses that
A method of treating an aromatic polyamide fiber with a mixture of a polyepoxide compound, a blocked isocyanate compound, and a rubber latex, and then treating with a treatment liquid in which a special chlorophenol compound is blended with a resorcinol / formaldehyde / rubber latex mixture (RFL). Have been.

According to these methods, although the adhesion between aromatic rubber fibers and general-purpose rubbers such as butadiene rubber and chloroprene rubber is improved, chlorinated polyethylene having excellent weather resistance and chemical resistance is obtained. Since it was difficult to obtain strong adhesion between the rubber and the aromatic polyamide fiber, the fact is that the development of chlorinated polyethylene rubber into the aromatic polyamide fiber reinforced composite material has not progressed.

[0007]

SUMMARY OF THE INVENTION The present invention has been achieved as a result of studying to solve the above-mentioned problems in the prior art.

Accordingly, an object of the present invention is to provide various rubbers,
Aromatic polyamide fiber for rubber reinforcement with excellent adhesiveness especially to chlorinated polyethylene rubber, its production method, and excluding concentrated nitric acid, as well as excellent adhesion between fiber and rubber, flexibility, weather resistance and flame retardancy An object of the present invention is to provide a fiber-reinforced rubber composite material which is stable against acids, alkalis and alcohols and is lightweight.

[0009]

In order to achieve the above object, an aromatic polyamide fiber for rubber reinforcement according to the present invention comprises a first treatment in which the surface of the aromatic polyamide fiber is treated with a first treatment containing a vinyl chloride copolymer latex. And then subjecting 5 parts of the blocked isocyanate compound or ethyleneimine compound to 100 parts by weight of the solid content of the mixture of the rubber latex and the resorcinol-formaldehyde precondensate.
It is characterized by being treated with a second treatment liquid containing a composition containing up to 15 parts by weight.

In the above, the rubber latex contained in the second treatment liquid is a chlorosulfonated polyethylene rubber latex, and the solid adhesion amount of the first treatment liquid to the aromatic polyamide fiber is 3.0 to 10%. .
0% by weight, and the amount of adhesion of the second treatment liquid to the aromatic polyamide fiber to which the first treatment liquid has adhered is 2.0 to 2.0%.
It is desirably 8.0% by weight.

The method for producing an aromatic polyamide fiber for rubber reinforcement according to the present invention comprises treating the aromatic polyamide fiber with a first treatment liquid containing a vinyl chloride copolymer latex and drying at 100 ° C. to 120 ° C. After that, 140-160
C. and a solids content of the mixture of rubber latex and resorcinol-formaldehyde precondensate of 10%.
0 parts by weight, treated with a second treatment liquid containing a composition containing 5 to 15 parts by weight of a blocked isocyanate compound or an ethyleneimine compound,
After drying at 0 ° C., heat treatment is performed at 200 ° C. to 250 ° C.

In the above method, the rubber latex contained in the second treatment liquid may be chlorosulfonated polyethylene rubber latex, and the solid adhesion amount of the first treatment liquid to the aromatic polyamide fiber may be 3 times. It is preferable to set the amount of the second processing solution to 2.0 to 8.0% by weight with respect to the aromatic polyamide fiber to which the first processing solution has adhered.

Further, the fiber-reinforced rubber composite material of the present invention reinforces rubber, especially chlorinated polyethylene rubber, with the above-mentioned aromatic polyamide fiber for reinforcing rubber or the aromatic polyamide fiber for reinforcing rubber obtained by the above-mentioned method. These are desirably formed in the form of tire cords, belts, hoses and the like.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described specifically.

The aromatic polyamide fiber used in the present invention is a fiber obtained by spinning and drawing aromatic poly-P-phenylene terephthalamide and poly-P-phenylene-3-4'diphenyl ether terephthalamide by known means. Means

The aromatic polyamide fibers used in the present invention include not only filament yarns made of the above-mentioned aromatic polyamide, but also cords, woven fabrics, woven fabrics, fabrics and non-woven fabrics made of the filament yarns. The treatment with the adhesive treatment liquid described below may be performed on the aromatic polyamide fiber in any form.

The vinyl chloride copolymer latex used in the first treatment liquid of the present invention includes vinyl chloride and olefins such as ethylene, propylene, isobutylene, butadiene, methyl acrylate, ethyl acrylate, n-butyl acrylate, Ethylhexyl acrylate,
Emulsions of copolymers with acrylates such as n-octyl acrylate and n-butyl methacrylate, and vinyl ester ethers such as vinyl acetate, vinyl laurate, isobutyl vinyl ether and butyl vinyl ether can be given.

The mixture of the resorcinol-formaldehyde precondensate (RF) and the rubber latex (L) used in the second treatment liquid of the present invention is generally called RFL.

The resorcinol-formaldehyde precondensate contained in this RFL is obtained by condensing resorcinol and formaldehyde in the presence of an alkali catalyst or an acid catalyst, and the molar ratio of resorcinol to formaldehyde is 1: 0. 3 to 1: 3.0, especially 1: 0.75 to 1:
It is preferably in the range of 1.50.

The rubber latex contained in the RFL includes vinyl pyridine-styrene-butadiene copolymer latex, styrene-butadiene latex, acrylonitrile-butadiene latex, chloroprene latex, chlorosulfonated polyethylene rubber latex, acrylate Examples include a system rubber latex, a natural rubber latex, and a vinyl chloride copolymer latex. Among them, the best results are obtained when chlorosulfonated polyethylene rubber latex is used.

The blocked isocyanate compound used in the second treating solution of the present invention is a compound which releases an active isocyanate compound by releasing a blocking agent by heat, and specifically includes tolylene diisocyanate, diphenylmethane diisocyanate, and meta-isocyanate. Polyisocyanate compounds such as phenylene diisocyanate, hexamethylene diisocyanate and triphenylmethane triisocyanate and phenols such as phenol, cresol and resorcin; lactams such as ε-caprolactam and valerolactam; oximes such as acetoxime, methyl ethyl ketone oxime and cyclohexane oxime Reaction products with a blocking agent selected from
In particular, aromatic compounds of diphenylmethane diisocyanate give good results.

Similarly, the ethyleneimine compound used in the second treatment liquid is diphenylmethane-bis-4,4
Aromatic and aliphatic isocyanates such as' -N, N'-diethyleneimine, 1,6-hexamethylenediethyleneimine, octadecyldiethyleneimine, tolylenediethyleneimine, naphthylenediethyleneimine, and triphenylmethanediethyleneimine, and ethyleneimine And aromatic ethyleneimine compounds give good results.

Next, the first processing liquid used in the present invention will be described.

The first bath treatment liquid containing a vinyl chloride copolymer latex is usually used at a solid concentration of 10 to 25% by weight, and the solid adhesion amount to the aromatic polyamide fiber at the time of treatment is 3.0 to 30% by weight. It is controlled to be 10.0% by weight.

When the solid content of the first bath treatment liquid to the aromatic polyamide fiber is less than 3.0% by weight, the adhesion to rubber cannot be sufficiently improved. This is not preferred because the properties of the polyamide fiber itself tend to be impaired.

The heat treatment after the application of the first treatment liquid is usually performed by drying at 100 to 120 ° C. for 0.5 to 5 minutes,
The heat treatment is performed at a temperature of about 160 ° C. for 0.5 to 5 minutes.

If the drying temperature after the application of the first treatment liquid is lower than 100 ° C., the treatment liquid components do not solidify and adhere to the rollers, reducing the amount of adhesion to the aromatic polyamide fibers and causing uneven adhesion to the rubber. Adhesion tends to deteriorate, and 1
At 20 ° C. or higher, blisters (scum) tend to occur.

Further, the heat treatment temperature after applying the first treatment liquid is 1
If the temperature is lower than 40 ° C., the adhesion to rubber cannot be sufficiently improved. If the temperature is higher than 160 ° C., the latex is thermally decomposed and a sufficient adhesiveness cannot be obtained.

Next, the second bath treatment liquid has a solid content of 100% by weight of a mixture (RFL) of a precondensate of resorcinol / formaldehyde (RF) and a rubber latex (L), particularly preferably a chlorosulfonated polyethylene rubber latex. The composition contains 5 to 15 parts by weight of the above blocked isocyanate compound or ethyleneimine compound per part by weight.

Here, when the blended amount of the blocked isocyanate compound or ethyleneimine compound in the second treatment liquid is less than 5 parts by weight based on 100 parts by weight of the solid content of the RFL, the adhesion between the aromatic polyamide fiber and the rubber is sufficiently improved. If the amount exceeds 15 parts by weight, the effect of improving the adhesiveness is saturated, and adding more than this amount is not preferable because it only increases the cost.

The second bath treatment liquid usually has a solid content of 1%.
It is used at 0 to 25% by weight, and the solid content adhered to the aromatic polyamide fiber at the time of treatment is 2.0 to 8.0% by weight based on the aromatic polyamide fiber to which the first treatment liquid is adhered.
Is controlled so that

When the solid content of the second bath treatment liquid to the aromatic polyamide fibers to which the first treatment liquid has adhered is less than 2.0% by weight, the adhesion to rubber cannot be sufficiently improved, and If it exceeds 0.0% by weight, the properties of the aromatic polyamide fibers themselves tend to be impaired, which is not preferred.

The heat treatment after the application of the second treatment liquid is usually performed by drying at 100 to 150 ° C. for 0.5 to 5 minutes,
Heat treatment is performed at a temperature of about 250 ° C. for 0.5 to 5 minutes.

If the drying temperature after the application of the second treatment liquid is lower than 100 ° C., the treatment liquid components do not solidify and adhere to the roller to reduce the amount of adhesion to the aromatic polyamide fiber, and cause uneven adhesion to the rubber. Adhesion tends to deteriorate, and 1
At 50 ° C. or higher, blisters (scum) tend to occur.

The heat treatment temperature after application of the second treatment liquid is 2
If the temperature is lower than 00 ° C., the adhesiveness to rubber cannot be sufficiently improved, and if the temperature exceeds 250 ° C., the RFL deteriorates, and the adhesiveness with rubber, especially chlorinated polyethylene rubber, tends to decrease. Not preferred.

The aromatic polyamide fibers thus treated and heat-treated with the first and second treatment liquids are then embedded in a rubber composition mainly composed of natural rubber or synthetic rubber, and added under pressure. By vulcanizing, a fiber-reinforced rubber composite material firmly bonded to the adherend rubber can be obtained, but among various rubbers, an excellent effect can be obtained particularly when chlorinated polyethylene rubber is used.

In the case where the fiber-reinforced rubber composite material is, for example, an automobile hose, the aromatic polyamide fiber bonded as described above may be an unvulcanized NBR composition or a chlorinated polyethylene rubber composition. After being double-braided on the tube, it is further vulcanized while being covered with unvulcanized chlorinated polyethylene rubber.

The vulcanization is performed at 150 ° C. to 170 ° C. by a usual method such as steam vulcanization or press vulcanization.
The vulcanization time may be appropriately selected depending on vulcanization conditions such as the vulcanization temperature.

Thus, according to the present invention, it is possible to efficiently obtain a fiber-reinforced rubber composite material having excellent adhesiveness between rubber and an aromatic polyamide fiber, being flexible, and eliminating defects such as generation of scum in a manufacturing process. The resulting fiber-reinforced rubber composite material can be applied to tire cords, power transmission belts, conveyor belts, and rubber hoses, especially automotive hoses such as radiator hoses, heater hoses, power steering hoses, and oil hoses. Demonstrate excellent performance.

[0040]

Next, the present invention will be specifically described with reference to examples. In addition, each measurement value in an Example is calculated | required by the following method.

[Peel Peel Adhesion (Chloride Polyethylene Rubber Adhesion Rate, Peeling Force)] Two chlorinated polyethylene rubber sheets, each of which is obtained by topping a treatment cord of an aromatic polyamide fiber at a density of 28 / inch, are treated with a treatment cord Laminate so as to be parallel, and press vulcanize under pressure at 150 ° C for 40 minutes.

Then, after allowing the composition to cool, both plies are put on 5c.
The force required for peeling at a tensile speed of m / min was measured, and this peeling force was expressed in Kg / inch.

The chlorinated polyethylene rubber adhesion rate (with release rubber) is obtained by observing the cord peeled off from the chlorinated polyethylene rubber with the naked eye, and expressing the portion where the chlorinated polyethylene rubber is adhered to the cord surface in percentage. did.

In the above adhesion evaluation, the Mooney viscosity (ML _{1 + 4} , 100 ° C.): 80, specific gravity: 1.08 to
1.20 chlorinated polyethylene unvulcanized rubber was used. Table 1 shows examples of compounding of the rubber composition.

[0045]

[Table 1] [Examples 1 to 5] By adding water to a vinyl chloride copolymer latex (trade name: G151 / G351, manufactured by Zeon Corporation, weight ratio 3: 7), the solid content concentration (10 ~ 25% by weight) of the first bath treatment liquid.

In addition, resorcinol 1 in the presence of caustic soda
Resorcinol-formaldehyde precondensate (RF) obtained by reacting 2 moles of formaldehyde per mole
And chlorosulfonated polyethylene rubber latex (C
SM ... L) were mixed so that the RF / L ratio became 1 / 5.6 by weight and aged for 24 hours.

An aqueous dispersion of diphenylmethane-bis 4,4′-N, N′-diethyleimine (ethyleneimine compound... C) was added at a predetermined ratio shown in Table 2 to 100 parts by weight of the solid content of the RFL solution. To obtain a second treatment liquid having a solid content concentration of 20% by weight.

On the other hand, 1500 denier multifilament 1 made of an aromatic polyamide fiber “Kevlar” manufactured by DuPont.
The book is twisted with a twist of 9.0 times / 10 cm into a cord to form a cord, and immersed in the first bath treatment solution using a computer treater (manufactured by Ritzler) (solid content adhesion amount 4.1).
５5.0 wt%), dried at 110 ° C. for 150 seconds, and subsequently heat-treated at 150 ° C. for 60 seconds.

Next, the cord to which the first treatment liquid is adhered is immersed in the second treatment liquid (solid adhesion amount of 4.0 to 6.
1% by weight), dried at 110 ° C. for 150 seconds,
Heat treatment was performed at 5 ° C. for 60 seconds.

Table 2 shows the evaluation results of the peel adhesion between the plies of the cord thus obtained.

The contents of the symbols in Table 2 are as follows. C: ethylene imine compound

[Table 2] [Comparative Examples 1 to 6] Using the same code as in the above example, immersion in the first treatment liquid having the composition shown in Table 3 (solid content adhesion amount of 0.1%).
3 to 1.0% by weight), dried at 140 ° C. for 150 seconds, and subsequently heat-treated at 240 ° C. for 60 seconds.

Then, it was immersed in the second treatment liquid having the composition shown in Table 3 to which the first treatment liquid was adhered (solid adhesion amount 7.0 to 7.0).
9.1% by weight), dried at 140 ° C. for 150 seconds, and subsequently heat-treated at 235 ° C. for 60 seconds.

The first treatment liquids of Comparative Examples 1 to 4 were prepared by using a polyepoxy compound (sorbitol polyglycidyl ether... B) or this polyepoxy compound (B) and ethyleneimine instead of the vinyl chloride copolymer latex. Using a mixture with a compound (diphenylmethane-bis4,4'-N, N'-diethylemine... C), the solid content concentration was changed in the range of 2.5% to 15% by weight as shown in Table 3. It was done.

The first treatment liquids of Comparative Examples 5 and 6 were the same as those of Examples 2 to 4 or the solid solution concentration was changed to 5% by weight (Comparative Example 5).

The second processing solutions of Comparative Examples 1 to 4 are the same as those of Example 1.

Further, the second treatment liquids of Comparative Examples 5 and 6 are those in which the blending of the ethyleneimine compound (D) is omitted or 3% by weight.

The contents of the symbols in Table 3 are as follows.

A: vinyl chloride copolymer latex (parts by weight) B: polyepoxy compound (parts by weight) C: ethyleneimine compound (parts by weight)

[Table 3] As is clear from the results in Tables 2 and 3, the aromatic polyamide fiber for rubber reinforcement of the present invention gives a fiber-reinforced rubber composite material having excellent adhesion to chlorinated polyethylene rubber.

[0059]

As described above, the aromatic polyamide fiber for rubber reinforcement of the present invention has excellent adhesion to various rubbers, especially chlorinated polyethylene rubber, and the fiber-reinforced rubber of the present invention reinforced with this fiber. Composite materials, especially fiber-reinforced chlorinated polyethylene rubber composite materials, have excellent adhesiveness between fibers and rubber, flexibility, weather resistance, flame retardancy, and are stable against acids, alkalis and alcohols except concentrated nitric acid, In addition to having light weight characteristics and eliminating defects such as scum generation in the manufacturing process, it has tire cords, power transmission belts, conveyor belts, rubber hoses, especially radiator hoses, heater hoses, power steering hoses and oils. Excellent performance when applied to automotive hoses such as hoses.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI F16L 11/04 F16L 11/08 A 11/08 D06M 15/72 // D06M 101: 36

Claims (11)

[Claims] 1. The surface of an aromatic polyamide fiber is treated with a first treatment liquid containing a vinyl chloride copolymer latex, and then the mixture is mixed with a rubber latex and a resorcinol-formaldehyde precondensate at a solid content of 100 parts by weight. An aromatic polyamide fiber for rubber reinforcement, which is treated with a second treatment liquid containing a composition containing 5 to 15 parts by weight of a blocked isocyanate compound or an ethyleneimine compound. 2. The aromatic polyamide fiber for reinforcing rubber according to claim 1, wherein the rubber latex contained in the second treatment liquid is chlorosulfonated polyethylene rubber latex. 3. The aromatic polyamide to which the first processing liquid has an amount of solids attached to the aromatic polyamide fibers of 3.0 to 10.0% by weight, and the second processing liquid has the first processing liquid attached thereto. 2.0-8.0% by weight of adhesion to fiber
The aromatic polyamide fiber for rubber reinforcement according to claim 1 or 2, wherein: 4. A method comprising treating an aromatic polyamide fiber with a first treatment liquid containing a vinyl chloride copolymer latex,
After drying at 0 ° C. to 120 ° C., heat-treating at 140 ° C. to 160 ° C., and then adding the blocked isocyanate compound or the ethyleneimine compound to 100 parts by weight of the solid content of the mixture of the rubber latex and the resorcinol-formaldehyde precondensate. An aromatic polyamide for rubber reinforcement, which is treated with a second treatment liquid containing a composition containing 5 to 15 parts by weight, dried at 100 to 150 ° C, and then heat-treated at 200 to 250 ° C. Fiber manufacturing method. 5. The method for producing an aromatic polyamide fiber for reinforcing rubber according to claim 4, wherein chlorosulfonated polyethylene rubber latex is used as the rubber latex contained in the second treatment liquid. 6. The solid content of the first treatment liquid with respect to the aromatic polyamide fiber is 3.0 to 10.0% by weight,
6. The rubber reinforcement according to claim 4, wherein an amount of the second treatment liquid adhered to the aromatic polyamide fiber to which the first treatment liquid adheres is 2.0 to 8.0% by weight. 7. For producing aromatic polyamide fibers for use. 7. The aromatic polyamide fiber for reinforcing rubber according to any one of claims 1 to 3, or the aromatic polyamide for reinforcing rubber obtained by the method according to any one of claims 4 to 6. A fiber-reinforced rubber composite material characterized by using rubber to reinforce rubber. 8. The fiber reinforced rubber composite material according to claim 7, wherein the rubber is a chlorinated polyethylene rubber. 9. The fiber-reinforced rubber composite material according to claim 7, which is a tire cord. 10. The fiber-reinforced rubber composite material according to claim 7, which is a belt. 11. The fiber-reinforced rubber composite material according to claim 7, which is a hose.