JPH10273883A - Polyamide fiber for rubber reinforcement - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber reinforcing polyamide fiber having good adhesiveness particularly to chloroprene rubber, remarkably improved heat resistance, and excellent in fiber strength retention and durability. SOLUTION: The polyamide fiber for rubber reinforcement of the present invention is obtained by coating a surface of the polyamide fiber with a resorcinol-formaldehyde initial condensate, 2-chloro-1,3-butadiene /
It is a polyamide fiber for reinforcing rubber obtained by treating with a treatment liquid containing a 2,3-dichloro-1,3-butadiene copolymer latex and a chlorophenol compound. 2-chloro-1,3-butadiene / 2,3-dichloro-1,3
The copolymerization amount of 2,3-dichloro-1,3-butadiene in the butadiene copolymer latex is preferably at least 20% by weight, and is particularly useful for reinforcing rubber hoses.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyamide fiber for reinforcing rubber which is useful as a reinforcing material for fiber reinforced rubber products such as rubber hoses, and more particularly to a polyamide fiber having good adhesion to chloroprene rubber. In addition, the present invention relates to a rubber reinforcing polyamide fiber having remarkably improved heat resistance and excellent in fiber strength retention and durability.

[0002]

2. Description of the Related Art Polyamide fibers represented by polycapramid (nylon 6) and polyhexamethylene adipamide (nylon 66) have high strength, high adhesiveness and excellent durability, and are suitable for various industrial uses. It is widely used especially as a rubber reinforcing cord such as a tire cord, a power transmission belt, a transport belt and a rubber hose.

[0003] Specific uses of rubber hoses using polyamide fibers as reinforcing materials include automotive hoses such as radiator hoses, heater hoses, power steering hoses, and oil hoses.

Among rubbers for power steering hoses, acrylonitrile / butadiene copolymer rubber having excellent oil resistance is generally used for inner tube rubber, and chloroprene rubber having excellent heat resistance and ozone resistance is generally used for outer rubber. It is used for

On the other hand, the properties required for the polyamide fiber used as a reinforcing material include not only high strength and high modulus, but also good adhesion to the rubber used and heat resistance. Characteristics, such as being superior.

However, since polyamide fibers generally have low adhesiveness to rubber, polyamide fibers are mixed with a resorcinol-formalin precondensate and rubber latex (RFL) for the purpose of exhibiting properties as a rubber reinforcing fiber. Is generally used to improve the adhesiveness with rubber by using as an adhesive treatment liquid.

[0007] The adhesive treatment liquid for acrylonitrile / butadiene copolymer rubber is a mixture of resorcinol / formalin precondensate and acrylonitrile / butadiene copolymer rubber latex, and the adhesive for chloroprene rubber is resorcinol / formalin. A mixture of an initial condensate and chloroprene rubber latex is usually used, and the adhesive treatment liquid is applied to a twisted polyamide fiber using a dipping device such as a cord setter, dried, and then stretched and heat-treated. The resulting treatment cord is used as a reinforcement.

However, the conventional treated cord thus obtained does not always have sufficient adhesiveness particularly to chloroprene rubber, and in order to obtain sufficient adhesiveness, it is necessary to attach the cord to the cord at the time of braiding the hose. Further, it was necessary to apply an adhesive such as RFL or rubber paste.

On the other hand, as described in Japanese Utility Model Publication No. 6-20945, polyamide fibers treated with an adhesive treatment solution containing acrylonitrile / butadiene copolymer rubber latex have sufficient heat resistance. However, the polyamide fibers treated with the conventional adhesive treatment liquid containing chloroprene rubber latex did not always have sufficient heat resistance.

[0010]

However, in recent years, engine rooms have become hotter and maintenance-free.
Automotive hoses are required to have further improved durability. For this reason, rubber materials are being converted to materials with excellent heat resistance, but as described above,
The fact is that the fiber as a reinforcing material does not always have sufficient heat resistance.

Accordingly, the present invention solves the above-mentioned problems in the prior art, and in particular, has good adhesion to chloroprene rubber, remarkably improved heat resistance, and excellent fiber strength retention and durability. It is a main object to provide a polyamide fiber for rubber reinforcement.

[0012]

In order to achieve the above-mentioned object, a polyamide fiber for rubber reinforcement according to the present invention is characterized in that the surface of the polyamide fiber is coated with a resorcinol-formaldehyde precondensate, 2-chloro-1,3-butadiene. / 2,3-dichloro-1,3-butadiene copolymer latex and a treatment liquid containing a chlorophenol compound.

In the polyamide fiber for reinforcing rubber of the present invention, 2-chloro-1,3-butadiene / 2,3
The copolymerization amount of 2,3-dichloro-1,3-butadiene in the dichloro-1,3-butadiene copolymer latex is 20% by weight or more, and a mixture of a resorcinol-formaldehyde initial condensate and a latex ( RFL) and the mixing ratio of the chlorophenol-based compound (C) (RFL /
C) is 1 / 0.1 to 1/2 in terms of solid content weight, resorcinol-formaldehyde precondensate (RF)
And the mixture ratio (RF / L) of 2-chloro-1,3-butadiene / 2,3-dichloro-1,3-butadiene copolymer latex (L) is 1/2 to 2 in terms of solid weight. 1
/ 10, and that the amount of the treatment liquid adhering to the polyamide fibers is in the range of 3.0 to 10.0% by weight in terms of solid content. By doing so, a more excellent effect can be obtained.

The rubber reinforcing polyamide fiber of the present invention is particularly useful for reinforcing a rubber hose such as reinforcing a rubber hose using chloroprene rubber for at least a part of a rubber layer.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

As the polyamide used in the present invention, nylon 6 or nylon 66, which can form a high-strength raw yarn, is used.
0 or more, preferably 3.5 or more high molecular weight nylon 66
Ultra-high-strength nylon 66 cord to which an antioxidant containing a copper compound is added for the purpose of imparting durability against deterioration due to heat, light, oxygen and the like is preferably used.

The method of spinning the polyamide fiber may be a method in which spinning and drawing are performed in two steps, or a method in which both steps are performed in one step. In addition, the polyamide fiber when applying the treatment liquid can take any form such as a filament yarn made of the above polyamide, a cord made of the filament yarn, a woven fabric or a braid made of the filament yarn or cord. .

The resorcinol-formaldehyde precondensate in the treatment solution of the present invention is obtained by reacting resorcinol and formaldehyde, usually in the presence of an alkali catalyst.

The molar ratio (F / R) of resorcinol (R) to formaldehyde (F) in the resorcinol-formaldehyde precondensate (RF) is from 1/1 to 3/1, particularly from 1/1 to 2/1. It is preferably within the range. If the molar ratio of resorcinol to formaldehyde is less than 1/1, the resulting reinforcing cord will have tackiness, and the process-passing property at the time of knitting a hose or the like will be significantly reduced. If it exceeds 3/1, it is difficult to obtain the desired adhesion to rubber, which is not preferable.

In the processing solution of the present invention, 2-chloro-1,2
The 3-butadiene / 2,3-dichloro-1,3-butadiene copolymer latex is obtained by emulsifying and copolymerizing 2-chloro-1,3-butadiene and 2,3-dichloro-1,3-butadiene. It is a latex of the obtained copolymer rubber (hereinafter, simply referred to as a copolymer latex).

[0021] 2,3-
The content of dichloro-1,3-butadiene is 20% by weight.
As described above, the content is particularly preferably 40% by weight or more.
The higher the 2,3-dichloro-1,3-butadiene content, the better the adhesion between the polyamide fiber and chloroprene rubber and the heat resistance of the polyamide fiber. However, when the content of 2,3-dichloro-1,3-butadiene exceeds 80% by weight, the adhesiveness is reduced, which is not preferable.

The mixture of the resorcinol-formaldehyde precondensate (RF) and the copolymer latex (rubber latex) in the treatment liquid of the present invention is generally RFL
In this RFL, the mixing ratio of the resorcinol-formaldehyde precondensate (RF) and the copolymer latex (L) is １ ／ in terms of solid weight ratio.
It is preferably in the range of 〜 to 1/10, particularly １ ／ to １ ／.

In the present invention, if the weight ratio of the resorcinol-formaldehyde precondensate to the copolymer latex in terms of solid content is less than 1/2, the treated cord and knitted fabric become too hard, and the On the other hand, if the ratio exceeds 1/10, the adhesiveness is not only poor, but also the adhesiveness of the cord and the knitted fabric is undesirably increased.

Examples of the chlorophenol compound in the treatment liquid of the present invention include "Casabond E" (manufactured by Thomas Swan), "Denabond", "Denabond A", and "Denabond K" (both manufactured by Nagase Kasei). 2-6
Bis (2,4-dihydroxyphenylmethyl) -4-chlorophenol is exemplified.

The chlorophenol compound is resorcinol
When mixed with formaldehyde / initial condensate, the adhesion between the chloroprene rubber and the polyamide fiber can be significantly improved.

In the present invention, the weight ratio of the solid content of RFL to the chlorophenol compound (C) (RFL /
C) is preferably 1 / 0.1 to 1/2. 1 /
If it is less than 0.1, satisfactory adhesion cannot be obtained,
On the other hand, when the ratio exceeds １ ／, the flexibility of the cord and the knitted fabric decreases, which is not preferable.

The processing solution of the present invention usually has a solid concentration of 10 to 10.
It is used at 20% by weight, and the amount of adhesion to the polyamide fiber may be treated so that the solid content conversion is in the range of 3.0 to 10.0% by weight.

In producing the rubber reinforcing polyamide of the present invention, the polyamide fiber is immersed in the above-mentioned treatment solution,
After drying at a temperature of 0 to 150 ° C, heat treatment is performed at a temperature of 150 to 240 ° C, preferably 170 to 220 ° C.

If the drying temperature after application of the treatment liquid is lower than 70 ° C., the RFL component of the treatment agent does not solidify and adheres to the roller,
This is not preferable because the amount of adhesion to the braid is reduced, adhesion unevenness occurs, and the adhesion to rubber deteriorates.

Further, when the heat treatment temperature is higher than 240 ° C., the RFL component of the treatment agent is deteriorated, and the adhesion to rubber is reduced. On the other hand, when the heat treatment temperature is 150 ° C. or lower, the adhesion to rubber is undesirably reduced.

The thus obtained polyamide fiber for rubber reinforcement according to the present invention has good adhesiveness to chloroprene rubber in particular, heat resistance is remarkably improved, and properties excellent in fiber strength retention and durability are obtained. Have

Therefore, the polyamide fiber for rubber reinforcement of the present invention has an optimum performance as a reinforcing material for a fiber reinforced rubber product, and a fiber reinforced rubber product reinforced by this polyamide fiber, for example, an automobile tire, a conveyor belt Rubber hoses for automobiles, such as radiator hoses, heater hoses, power steering hoses, and oil hoses, such as V-belts and hoses, have high adhesive strength between rubber and polyamide fiber, and have excellent heat resistance and burst resistance. It has high quality performance.

Among them, an excellent effect is exhibited for rubber hoses, especially for rubber hoses using chloroprene rubber for at least a part of the rubber layer. For example, acrylonitrile / butadiene copolymer rubber having excellent oil resistance is used for the inner tube rubber. In a power steering hose using chloroprene rubber having excellent heat resistance and ozone resistance as an outer rubber, excellent effects are exhibited when at least the above-mentioned rubber reinforcing polyamide fiber is used as an outer reinforcing layer. In a rubber hose having two reinforcing layers, it is effective to use the above-described rubber reinforcing polyamide fiber as at least the outer reinforcing layer.

[0034]

EXAMPLES Hereinafter, the structure and effects of the present invention will be described more specifically with reference to examples. In addition, each measured value in the following examples was obtained by the following method.
In addition, parts and% in Examples all show parts by weight and% by weight.

[Cord strength] Measured according to JIS L-1017 (1983) using "Tensilon".

[Heat resistance] The treated cord was placed in an oven heated to 140 ° C. and heat-treated for 500 hours. After taking out the cord, the cord strength was measured by the above method, and the heat resistant strength retention was determined from the following equation. Heat retention strength = (Cord strength after heat treatment / Cord strength before heat treatment) x 100 (%)

[Adhesiveness] A test piece having a width of 25 mm was prepared using a rubber having the composition shown in Table 1 below and a treatment code, and the treatment code was determined according to the peel test method described in JIS K-6328 (1995). / The peel force between the rubbers was measured.

[0038]

[Table 1] Rubber compounding formulation Chloroprene rubber 100 parts by weight Zinc white 5.0 {MgO 4.0} Stearic acid 0.5 { Carbon black 30.0 } [Example 1] 18.6 parts of resorcinol, formalin aqueous solution (37 % Concentration) and 30 parts of an aqueous sodium hydroxide solution (1% concentration) were dissolved in 202.5 parts of water, and reacted under stirring for 2 hours. This is designated as solution A.

Next, 2-chloro-1,3-butadiene /
2,3-dichloro-1,3-butadiene copolymer latex (2,3-dichloro-1,3-butadiene content:
(10%, solid content: 50%) 249.6 parts, water 232.3
And 250.0 parts of "Casabond E" (manufactured by Thomas Swan Co., solid content: 20%) were mixed and reacted under stirring for 6 hours. This is designated as solution B.

Further, the solution A and the solution B were mixed and aged for 48 hours to obtain a solution C, that is, a treatment solution of the present invention.

On the other hand, a high-molecular-weight nylon 66 was melt-spun and stretched to obtain an original yarn having a strength of 11.2 g / d.
Two of the 0 denier multifilament yarn, 9 times / 1
The cord was twisted with a twist number of 0 cm to form a cord, immersed in the above treatment solution using a computer treater (manufactured by Ritzler), dried at 130 ° C. for 120 seconds, and subsequently heat-treated at 210 ° C. for 45 seconds. The deposition amount of the processing liquid of the obtained processing code was 6.5%. Table 2 shows the results of evaluating the heat resistance and adhesiveness of the treated cord.

Examples 2-6 and Comparative Examples 1-2 Table 2
As described above, all operations were the same as in Example 1 except that some conditions were changed. Table 2 also shows the results of evaluating the heat resistance and adhesiveness of the obtained treated cord. As is clear from the results in Table 2, the rubber reinforcing fibers of the present invention (Examples 1 to 6) have good adhesion to chloroprene rubber, and have significantly improved heat resistance compared to conventional polyamide fibers. Was.

[0043]

[Table 2]

[0044]

The polyamide fiber for rubber reinforcement of the present invention comprises:
In particular, it has good adhesiveness to chloroprene rubber, has remarkably improved heat resistance, and has properties excellent in fiber strength retention and durability.

Therefore, the polyamide fiber for rubber reinforcement of the present invention has the optimum performance as a reinforcing material for fiber reinforced rubber products such as rubber hoses, and fiber reinforced rubber products reinforced with this polyamide fiber, especially radiators. Automotive rubber hoses, such as hoses, heater hoses, power steering hoses, and oil hoses, exhibit high-grade performance because they have high adhesive strength between rubber and polyamide fibers, and have excellent heat resistance and burst resistance. I do.

Claims (6)

[Claims] 1. The method of claim 1, wherein the surface of the polyamide fiber is resorcinol-formaldehyde precondensate, 2-chloro-1,3-
A polyamide fiber for rubber reinforcement, which has been treated with a treatment solution containing butadiene / 2,3-dichloro-1,3-butadiene copolymer latex and a chlorophenol compound. 2. 2-chloro-1,3-butadiene /
2. The copolymerization amount of 2,3-dichloro-1,3-butadiene in a 2,3-dichloro-1,3-butadiene copolymer latex is 20% by weight or more.
The polyamide fiber for rubber reinforcement according to the above. 3. A mixing ratio (RFL / C) of a mixture (RFL) of a resorcinol-formaldehyde precondensate and latex to a chlorophenol compound (C) is 1 / 0.1 to 1 in terms of solid weight. The polyamide fiber for rubber reinforcement according to claim 1 or 2, wherein the ratio is 1/2. 4. A resorcinol-formaldehyde precondensate (RF) and 2-chloro-1,3-butadiene /
The mixing ratio (RF / L) with the 2,3-dichloro-1,3-butadiene copolymer latex (L) is 1/2 to 1/10 in terms of solid content weight. 1
The polyamide fiber for rubber reinforcement according to any one of claims 1 to 3. 5. The rubber reinforcement according to claim 1, wherein an amount of the treatment liquid attached to the polyamide fiber is 3.0 to 10.0% by weight in terms of a solid content. For polyamide fiber. 6. The polyamide fiber for reinforcing rubber according to claim 1, wherein the polyamide fiber is for reinforcing rubber hose.