JPH1096171A - Treatment for polyester yarn for reinforcing rubber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for treating a polyester for reinforcing rubber, capable of improving adhesiveness between a polyester yarn and rubber, not causing gum-up phenomena in a treating process, bettering workability and productivity and providing a high-quality product. SOLUTION: A polyester yarn is treated with an adhesive solution which is obtained by mixing a precondensate between a resorcinol and formaldehyde with a rubber latex, aging the solution and blending the solution with an aqueous solution of a condensate of 2,6-bis(2',4'-dihydroxyphenylmethyl)-4- chlorophenol, 2,6-dihydroxyphenylmethyl)-4-chlorophenol and resorcinol in ammonia water having >=70 centipoise viscosity measured in a solution at 20±0.5wt.% solid content concentration, at pH >=10 at 20±0.2 deg.C and swelling laminar clay minerals and then heat-treated at 210-250 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for treating polyester fibers used for reinforcing rubber products such as tires, conveyor belts, V-belts, hoses and the like.

[0002]

2. Description of the Related Art Polyethylene terephthalate and polyester fibers mainly composed of polyethylene terephthalate have excellent strength and dimensional stability and are widely used as rubber reinforcing fibers. However, polyester fibers have a drawback of poor adhesion to rubber, and various methods for improving the adhesion between polyester fibers and rubber have been conventionally proposed.

As a typical method, a liquid (RFL liquid) comprising an initial condensate of resorcinol and formaldehyde and a rubber latex (RFL liquid) is added to 2,6-bis (2 ', 4'-dihydroxyphenylmethyl) -4-chlorophenol. (Japanese Patent Publication No. 46-11251). However, in this method, sufficient adhesive strength is not obtained, and the amount of the adhesive to be applied is increased in order to increase the adhesive strength, or when the heat treatment temperature after the adhesive is applied is increased, the subsequent steps, for example,
In processes such as softening and topping to rubber, there has been a problem that the adhesive falls off, the adhesive strength decreases, the appearance deteriorates, and the fiber strength decreases due to high-temperature heat treatment.

[0004]

SUMMARY OF THE INVENTION The present invention exhibits a high adhesive strength without increasing the amount of adhesive applied and without increasing the heat treatment temperature after the adhesive is applied, and reduces the gum-up phenomenon in the processing step. An object of the present invention is to provide a method for treating a rubber reinforcing polyester fiber which does not cause the problem, improves workability and productivity, and provides a high quality rubber reinforcing polyester fiber.

[0005]

The present invention solves the above-mentioned problems, and the gist thereof is as follows. The polyester fiber is mixed with an initial condensate of resorcinol and formaldehyde and a rubber latex, and aged (a), and aged with 2,6-bis (2 ', 4'-dihydroxyphenylmethyl) -4-chlorophenol; Aqueous ammonia solution of condensate of 2,6-dihydroxymethyl-4-chlorophenol and resorcinol, solid concentration 20 ± 0.5% by weight, p
A solution having a viscosity of at least 70 centipoise measured at a temperature of 20 ± 0.2 ° C. (b) and a swellable layered clay mineral (c) are added to a solution of H10 or more, and the mixture is treated with an adhesive solution obtained by mixing. A method for treating a polyester fiber for rubber reinforcement, comprising heat-treating at a temperature of 250 ° C.

[0006]

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

The polyester fiber in the present invention is in the form of a filament yarn, a twisted yarn, a cord, a woven fabric, a non-woven fabric or the like made of polyethylene terephthalate and polyester mainly composed of the same. Further, the polyester fiber may be one obtained by imparting an epoxy compound or the like in the spinning process to improve the adhesiveness.

In the present invention, the initial condensate of resorcinol and formaldehyde is a molar ratio of resorcinol to formaldehyde of 1: 0.5 to 6, preferably 1: 6.
In 1-3, an initial condensate condensed using an alkali or acidic catalyst is suitable.

[0009] As rubber latex, "Piratex" (trade name of Sumitomo AV Latex Co., Ltd.), "JSR-06
52 "(trade name of Japan Synthetic Rubber Co., Ltd.)," Nippol 2518F
VP latex such as "S", "Nippol 2518GL" (trade name of Nippon Zeon), SBR latex such as "JSR-2108" (trade name of Nippon Synthetic Rubber), "Nippol LX-112" (trade name of Zeon Corporation) And the like are preferably used.

The RFL solution (a) is prepared by mixing an initial condensate of resorcinol and formaldehyde and a rubber latex at a solid content ratio of 1: 1 to 15, preferably 1: 3 to 12 by weight. . If the rubber latex ratio is too small, the treatment cord will cure and the adhesive strength will decrease,
If it is too large, the tackiness of the treated cord increases, causing troubles, and a satisfactory adhesive strength cannot be obtained.

In the present invention, the solution (b) of the condensed phenol compound to be mixed with the RFL solution is 2,6-bis (2 ′, 4 ′).
-Dihydroxyphenylmethyl) -4-chlorophenol, 2,6-dihydroxymethyl-4-chlorophenol and resorcinol can be obtained by reacting them in an appropriate molar ratio in an aqueous alkali solution. The solution (b) must have a high viscosity of 70 centipoise or more as measured by the above method, that is, a high molecular weight solution capable of forming a strong adhesive film on the fiber surface. As such a high-viscosity condensed phenol compound, a high-viscosity type “Denabond” (trade name of Nagase Kasei Kogyo Co., Ltd.) is preferably used.

RF of solution (b) of condensed phenol compound
The amount of the solid added to the liquid L is suitably 10 to 50 parts, preferably 20 to 40 parts, per 100 parts of the solid weight of the RFL liquid. If the addition amount is too small, high adhesive strength cannot be obtained, and if it is too large, the adhesive force tends to decrease, and the adhesive drops off, gumming becomes remarkable, causing troubles such as roller contamination, It is not preferable because it causes hardening of the treatment code and cost increase.

The swellable layered clay mineral (c) includes a synthetic smectite composed of silicon, magnesium, aluminum, oxygen and a hydroxyl group. Commercial products of such a swellable layered clay mineral include "Lucentite SWN" and "Lucentite SPN" (trade name of Corp Chemical).

In order to uniformly disperse the swellable layered clay mineral (c) in the RFL solution, it is preferable to add the swellable layered clay mineral to the RFL solution in the form of an aqueous dispersion of about 2% by weight. It is appropriate that the addition amount is 0.05 to 1.00 part, preferably 0.10 to 0.50 part by weight of the solid content with respect to 100 parts by weight of the solid content of the RFL liquid. If the added amount is too small, high adhesive strength cannot be obtained, and if it is too large, the viscosity of the adhesive liquid becomes high, and it becomes difficult to adjust the applied amount, or the adhesive strength tends to decrease, and the cost increases. Invited,
Not preferred.

In the present invention, the polyester fiber is treated with the adhesive liquid prepared as described above. In this treatment, usually, the polyester fiber is immersed in an adhesive solution, and the fiber to which the adhesive solution has adhered is squeezed by a squeezing roller whose pressure has been adjusted, or passed through a Duevar device whose degree of pressure has been adjusted.
Excess adhesive liquid is removed, and the amount of adhesive liquid (dip)
It is usually adjusted to 1 to 10% by weight, preferably 2 to 7% by weight.

The polyester fiber provided with the adhesive liquid is
Next, it is usually dried at 80 to 160 ° C for 0.5 to 10 minutes, and then heat-treated at 200 to 250 ° C for 0.5 to 5 minutes. If the temperature of this heat treatment is less than 200 ° C, the formation of the adhesive film on the fiber and the reaction with rubber are insufficient, and a satisfactory adhesive strength cannot be obtained. The formed adhesive film is deteriorated to lower the adhesive strength, and the polyester forming the fiber is thermally decomposed, so that the strength and the like of the fiber are lowered, which is not preferable.

In the present invention, the treatment with the adhesive liquid is usually one-step treatment.
After the first stage treatment with the adhesive liquid according to the present invention, the usual RFL
The liquid may be subjected to the second stage treatment, or the adhesive solution of the present invention having a different concentration may be subjected to the second stage treatment (usually, the concentration of the second stage is lowered).

The polyester fiber thus treated and heat-treated with the adhesive liquid is embedded in a rubber composition mainly composed of natural rubber or synthetic rubber, and is heated under pressure to be vulcanized. And glued.

[0019]

In the present invention, a strong adhesive film is easily formed on the fiber since the adhesive liquid contains a high-viscosity, that is, high-molecular-weight condensed phenol compound, and the heat treatment temperature after applying the adhesive is relatively low. It is recognized that a low adhesion shows a high adhesive strength. In addition, since the swellable layered clay mineral is blended, the viscosity of the adhesive liquid becomes uniform, and the adhesive liquid is adhered to the fibers in a uniform state, whereby a uniform adhesive film is recognized.

[0020]

Next, the present invention will be described specifically with reference to examples. In the examples, "parts" means parts by weight, and the measuring method is as follows. (1) Solid concentration The sample (aqueous ammonia solution) was added to a magnetic crucible of known weight.
５5 g is precisely weighed, collected, evaporated to dryness on a water bath, dried at 120 ° C. for 1 hour, cooled, weighed to determine the amount of the residue, and the solid concentration is calculated. (2) A sample was taken in a pH beaker, and the pH of the glass electrode-calomel electrode was measured.
Measure with an H meter. (3) Take a sample in a viscosity measurement container and set the temperature to 20 ± 0.2 in a thermostat.
C. and adjusted with a BL-type rotational viscometer (Tokyo Keiki Co., Ltd.). If the solid content of the sample is more than 20.5% by weight, dilute it with 5N or 5N or more ammonia water. On the other hand, if the solid content of the sample is less than 19.5% by weight, Evaporate slowly at a temperature of 50 ° C. or less, adjust the solid content of the sample to 20 ± 0.5% by weight, and measure the viscosity. If the pH is less than 10, 28
% Ammonia water to adjust. (4) Adhesive strength Using a rubber compound having the composition shown in Table 1, JIS-L1017 (198
3) Adhesion-Measured according to the A method.

[0021]

[Table 1]

(5) Dip adhesion amount Measured according to the dip pickup and dissolution method (2) of JIS-L-1017 (1983).

Examples 1 and 2 and Comparative Examples 1 to 3 After adding 820 parts of water to 32 parts of a 10% aqueous solution of sodium hydroxide, 41 parts of resorcinol were added, followed by stirring and dissolving. Then
36 parts of 37% formalin is added, and the mixture is stirred for 5 minutes and reacted at 25 ° C. for 2 hours. The obtained reaction solution was mixed with V at a solid concentration of 41%.
P latex: added to 605 parts of "pylatex" with stirring, stirred and mixed for 10 minutes, and then aged at 25 ° C for 22 hours to obtain an RFL solution (a). To this RFL solution (a), 2 weights of an aqueous ammonia solution having a solid content concentration of a condensed phenol compound of 20%: "Denabond" (DB) (b) and the swellable layered clay mineral "Lucentite SWN" (RT) (c) %
The aqueous dispersion was added in the amount (parts) shown in Table 2 and stirred to obtain adhesive liquids A to E. (Adhesive liquids B, C, and D are for comparative examples.)

[0024]

[Table 2]

The polyethylene terephthalate chips are supplied to an extruder type melt spinning machine, and the spinning temperature is 300 to 305.
The polyester fiber was spun and stretched at 1500C to obtain a 1500 d / 252 f polyester yarn. The obtained polyester yarn has an intrinsic viscosity (using an equal weight mixture of phenol and ethane tetrachloride as a solvent,
(Measured at 20 ° C) 0.92, terminal carboxyl group concentration 23 eq /
10 ⁶ g, strength was 8.7 g / d.

[0026] The two polyester yarns are plied 40 times / 10 times.
The cord was immersed in each of the above adhesive liquids using a Ritzler computer and dried at 120 ° C. for 100 seconds.
Heat treated for 20 seconds. The treatment code thus obtained was embedded in a rubber sheet having the composition shown in Table 1, and a pressure of 100 kg was applied.
Vulcanized at 150 ° C./cm ² for 30 minutes, and the adhesive strength was measured. Table 3 shows the dip adhesion amount and the adhesive strength.

[0027]

[Table 3]

As is evident from Table 3, in Examples 1 and 2 of the present invention, the adhesion between the treated cord and the rubber is good, and the dirt on the rollers and the like which are in contact with the polyester fiber is small. There was no operational problem. On the other hand, in Comparative Examples 1 to 3, although there was no dirt on the rollers and the like, the adhesion between the treated cord and the rubber was not satisfactory.

[0029]

According to the present invention, the adhesiveness of the polyester fiber to the rubber is improved, the work-up and productivity are improved without causing a gum-up phenomenon in the processing step, and a high-quality product is produced. A method of treating a given polyester fiber for rubber reinforcement is provided.

Claims (1)

[Claims] 1. A liquid obtained by mixing a polyester fiber with an initial condensate of resorcinol and formaldehyde and a rubber latex and aging the mixture, and adding 2,6-bis (2 ', 4'-dihydroxyphenylmethyl)- 4-chlorophenol,
Ammonia aqueous solution of condensate of 2,6-dihydroxymethyl-4-chlorophenol and resorcinol, solid content concentration
For a solution of 20 ± 0.5% by weight and pH 10 or more, temperature 20 ±
Add and mix with a viscosity of 70 centipoise or more measured at 0.2 ° C (b) and a swellable layered clay mineral (c), treat with an adhesive solution obtained, and then heat-treat at a temperature of 210 to 250 ° C. A method for treating a polyester fiber for rubber reinforcement.