JPS59142128A - Method for adhesion treatment of polyester fiber for reinforcing rubber - Google Patents

Abstract

PURPOSE:To obtain firm adhesion of polyester fiber to rubber, by treating the polyester fibers for reinforcing the rubber in a first treating bath containing an polyepoxide compound, and then in a second treating bath containing carbon block, etc. CONSTITUTION:Polyepoxide compounds should be a compound containing two or more epoxy groups per molecule, and are preferably a reaction product that is obtained by reacting a polyhydric alcohol such as glycol with epichlorohydrin. Carbon black is formulated into an aqueous dispersion using any dispersant, and for example SAF, ISAF, HAF, etc. are used. The reason why it is flexible and a high rubber adhesion is obtainable is due to the fact that the bonding strength of the polyepoxide compound and the polyester fiber or the two-pack system treating liquid is enhanced by the carbon black.

Description

DETAILED DESCRIPTION OF THE INVENTION (Subject of the Invention) The present invention relates to a method for adhesion treatment of polyester fibers for rubber reinforcement, which has improved adhesion to rubber.

(Background) Polyester fibers generally have excellent properties such as tensile strength and dimensional stability, and are suitable as rubber reinforcing materials for automobile tires, conveyor belts, belts, hoses, etc. However, polyester fibers have poor adhesion to rubber, so
Many proposals have been made to date to improve adhesiveness.

For example, a method in which polyester fibers are treated with a first treatment bath containing a polyepoxide compound and an aromatic polyisocyanate compound, and then treated with a second treatment bath containing resorcinol, formaldehyde, and rubber latex (Japanese Patent Publication No. 42-11
No. 482] is known. Fiber materials treated with this method exhibit relatively good adhesion to rubber, but the fiber materials become hard and difficult to bend during molding.
It has the disadvantage that fatigue resistance is significantly reduced.

(the purpose) Therefore, an object of the present invention is to eliminate the above-mentioned drawbacks.

(Structure) The object of the present invention is to treat polyester fibers for rubber reinforcement with a first treatment bath containing an aqueous solution of a polyepoxide compound, and then with a second treatment bath containing resorcinol, formaldehyde, rubber latex, blocked polyisocyanate compound, and carbon black. This is achieved by processing.

Hereinafter, the method of the present invention will be described in more detail.

(Details of Structure) The polyester fiber used in the present invention means a yarn, cord, or woven fabric made of aromatic or naphthalene ring-containing linear polyester such as polyethylene terephthalate and polyethylene naphthalate. It goes without saying that polyvarnish is used here, but the treatment of the present invention can be applied in any form. For example, after being treated in the first treatment bath in the form of a yarn, it may be formed into a cord or woven fabric and then treated in the second treatment bath, or it may be treated in the form of a cord in the first treatment bath and then in the second treatment bath. It may be processed with

The polyepoxide compound used in the first treatment bath of the present invention is a compound having two or more epoxy groups in one molecule, and includes polyhydric alcohols such as ethylene glycol, glycerol, sorbitol, pentaerythritol, and polyethylene glycol, and epichlorohydrin. Reaction products with halogen-containing epoxides such as resorcinol.
Examples include reaction products of polyhydric phenols such as formaldehyde resins and the halogen-containing epoxides. Preferably, a reaction product obtained by reacting a polyhydric alcohol, such as glycerol, with epichlorohydrin is used.

The first bath in the present invention is composed of an epoxide compound and water, and contains the epoxide compound in an amount of 05 to 150% by weight, preferably 2.0 to 100% by weight. Here, if the amount of adhesion is outside the above range and is too small, the rate of rubber adhesion to the treated polyester fibers will be poor, and if it is too much, the treated polyester fibers will become hard, leading to a decrease in fatigue resistance.

The blocked polyisocyanate compound used in the second treatment bath of the invention is an addition compound of a polyiso7anate compound and a blocking agent, and the following compounds are used.

Examples of the polyisocyanate compound include polyisocyanates such as tolylene diiso/anate, metaphenylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, and triphenylmethane triincyanate.

Examples of blocking agents include phenol, cresol,
These include phenols such as resorcinol, lactams such as caprolactam and parerolactam, oximes such as acetoxime and methyl ethyl ketone oxime, 6th alcohols such as t-butanol and t-pentanol, and ethyleneimine.

The carbon black used in the second treatment bath of the present invention is preferably blended as an aqueous dispersion using an arbitrary dispersant. Average particle size for carbon black is 11 mμ
~500 mμ carbon blacks commonly used in the rubber industry, such as S A 111, 15AF, HAF,
GPF+FT+MT.

EPC, MPC, FF, S, RF, etc. are used.

The second treatment bath in the present invention includes (X) a mixture of an alkali-containing resorcinol/formaldehyde initial condensate and rubber latex (RFL), (Yl blocked polyisocyanate compound, tz+carbon black, +V+carbon black dispersant) and (W) water.

The second treatment bath is created, for example, by the following procedure.

A resorcinol/formaldehyde initial condensate (RF) is obtained with water, resorcinol, formaldehyde, and caustic soda.

The condensate is added to rubber latex to obtain a resorcinol/formaldehyde/rubber latex mixture (RFL).

Meanwhile, water, caustic soda, a dispersant, and carbon black are well dispersed to obtain a carbon black dispersion.

A blocked polyisocyanate compound/carbon black dispersion is mixed with the resorcinol/formaldehyde/rubber latex mixture and stirred well to obtain a second treatment bath of resorcin/formaldehyde/rubber latex/blocked polyisocyanate compound/carbon black. It will be done.

To prepare the second treatment bath, it is possible to add a blocked polyisocyanate compound and carbon black to the resorcinol/formaldehyde/rubber latex liquid and then use it after aging. After aging, a blocked polyisocyanate compound and carbon black may be added and used immediately before processing the polyester fiber. Aging of resorcinol/formaldehyde/rubber latex is usually carried out at 20 to 30°C for 24 hours or more. The second treatment bath containing resorcinol, formaldehyde, rubber latex, blocked polyinsyanate compound, and carbon blank is usually adjusted to contain 15 to 25% by weight of solids.

The second treatment bath of the present invention includes resorcinol, formaldehyde,
Rubber latex fXl, blocked polyisocyanate compound (Y), carbon black fZ], the weight ratio of (x):(yl) is 100:5.
~+00:30. Preferably +o.

:10 to +00:25.

((x) + fy)) : (z) weight ratio is 100
:, 0.5-10020, preferably +00:
Preferably, the ratio is in the range of 0.8 to 100:10.

Here, if the coulometric ratio (Yl/(x)) is small, the rate of rubber adhesion to the treated polyester fibers will be poor; if it is large, the treated polyester fibers will become hard, leading to a decrease in fatigue resistance.

If iZl/' ((X) + (Yl) is small, the rate of rubber adhesion to the treated polyester fibers will be poor. Even if it is increased, the contribution to improving the rate of rubber adhesion to polyester fibers will be small.

Any method such as immersion in a liquid bath or spraying from a nozzle can be used to apply the first treatment bath and the second treatment bath to the polyester fibers. The amount of solid content deposited on the polyester fiber is 0.0 as the first treatment bath composition.
5-330% by weight, preferably 0.5-2.2% by weight,
The second treatment bath composition is 4.0 to 60% by weight of ZO, preferably 45 to 60% by weight. If the amount of solid content attached is too small, the adhesion force will decrease, and if it is too large, the adhesive-treated polyester fiber will become hard.

In order to control the amount of solid content attached to the polyester fibers, means such as squeezing with a pressure roller, blowing off with air, suction, etc. may be used.

In the present invention, after the polyester fibers are treated with the first treatment bath, they are dried at a temperature of room temperature to 150°C, and
heat treatment at a temperature of 0 °C, preferably 180-220 °C, then treated in a second treatment bath and dried at a temperature of 60-150 °C, and a temperature of 200-260 °C, preferably 250 °C.
Heat treatment at a temperature of ~250°C. If the heat treatment temperature is too low, adhesion to the rubber will be insufficient, while if the heat treatment temperature is too low, the polyester fibers will melt and the strength will drop significantly, making it impossible to put it to practical use.

Polyester fibers treated in this way have general properties such as excellent tensile strength and dimensional stability for rubber reinforcement, and are especially flexible, have low bending hardness, have excellent moldability, and are resistant to fatigue. Furthermore, the rubber adhesion rate of polyester fibers is extremely high when subjected to a peel adhesion test after being embedded in compounded rubber and vulcanized.

Although it is not clear why the present invention provides a flexible polyester fiber with an extremely high rubber adhesion rate,
The bonding force between the polyepoxide compound in the first treatment liquid and the polyester fiber is ≦, the effect of being strengthened by the carbon black paste contained in the second treatment liquid, and the bonding force between the polyepoxide compound and the components contained in the second treatment liquid. It is thought that the bonding force of carbon black is strengthened by the presence of carbon black.

Judging from the characteristics of chic, the following numbering will be possible.

That is, functional groups such as carboxyl groups, carbonyl groups, quinone groups, hydroxyl groups, etc. present on the surface layer of the particles react with the polyepoxide compound and blocked ison anate compound, which are the components of the treatment liquid, to form strong chemical bonds. and the structural feature of the particles having a large surface area increases the number of contact points with each component in the treatment liquid and strengthens the cohesive force within the adhesive layer. It is presumed that a strong adhesive bond can be obtained between the polyester fiber and the polyester fiber.

The present invention will be explained in more detail below with reference to Examples. In the examples, the inter-ply peeling force indicates the adhesive strength between polyester fiber and rubber, and the treated cords were inserted between two plies of treated cords at a 90 degree angle to cross-ply (cord density: 50 degrees). Embedded in carcass compound rubber for automobile tires as end/25 m) and heated at 150°C.
After vulcanization with a press for 30 minutes, 50 shoulders/
The force required to peel off the sample at a tensile speed of 20 kg/20 min is calculated by applying the force required to peel it off at a tensile speed of 20 kg/20 min. Rubber adhesion rate is also a measure of the adhesion of rubber to polyester fibers.The cord that has been peeled off from the rubber during the inter-ply peel force measurement described above is observed with the naked eye, and the portion of the cord surface where rubber is adhered is graded into five grades. (A
(Rubber adhesion rate 81-100%), B (Rubber adhesion rate 61-100%)
80%], C (rubber adhesion rate 41-60%), D (rubber adhesion rate 21-4'0%), E (rubber adhesion rate 20% or less)]
There are many things that have been classified into different symbols. The bending hardness of the cord was measured using a set of tapers, and the measured value was 0 (
Indicates a hard core. Furthermore, the strength retention rate is a measure of fatigue resistance, and is the percentage of strength remaining after the cord is subjected to repeated fatigue of 5% elongation and 10% compression between rotating discs for 48 hours (1705 rpm) using a Gutdrich disc tester. It was a hailstorm.

Example 1 5 g of glycerol boriglycidyl ether (Dicor FiX-514, manufactured by Nagashio Sangyo Co., Ltd.) was uniformly dissolved in 995 g of distilled water, and the resulting aqueous solution was used as a first treatment bath.

On the other hand, 560.48 g of distilled water, 18.9 g of resorcinol
g, 27.67 g of 57% formaldehyde, and 51 g of 1% aqueous sodium hydroxide solution.
j0.5% emulsion 1) 422.99g128% ammonia 19.45g'.

Distilled water114. , 2 g was added to the mixture while stirring slowly and aged for 24 hours. After completion of aging, 80 g of a 25% aqueous dispersion of a phenol-blocked product of diphenylmethane diisocyanate (manufactured by DuPont) (Ylene MP) is added and dispersed in the resorcinol/formaldehyde/rubber 7-fucks mixture. Next, 24 g of distilled water, 5 g of 1% caustic soda, 1.0 g of lignin sulfonic acid, and IQ g of carbon black (HAF manufactured by Asahi Carbon Co., Ltd.) were mixed in a ball mill for 48 hours, and 1 or 2 parts of the dispersion was mixed with resorcinol. - Add and mix the formaldehyde, rubber latex, and blocked polyisocyanate compound mixture and use the resulting mixture as a second treatment bath.

15QQD 72 pieces, top twist 40 times/10 pieces, bottom, twist 4
A cord made of polyester fiber with 0 times/10 cIR is treated with a computer treater (manufactured by C.A. Ritzler)
After immersing the sample in the first treatment bath using the same method, it is dried at 100°C for 150 seconds, and then heat-treated at 200°C for 30 seconds. Next, it is immersed in a second aqueous bath, dried at 100°C for 150 seconds, and then heat-treated at 245°C for 60 seconds.

The treated polyester cord has a solid content o in the first treatment bath;
o 5% by weight of the resin and the solid content of the second treatment bath was 4.8% by weight. The resulting treated cord was measured for inter-ply peel strength, rubber adhesion rate, cord strength, cord bending hardness, and strength retention after fatigue. The results are shown in Table 1.

In Examples 2 to 18, the total solid concentration of the polyepoxide compound in the first treatment bath was changed, and the mixing ratio of the blocked polyinocyanate compound and carbon black in the second treatment bath was also changed.

For comparison, Comparative Example-1 is obtained by removing the polyepoxide compound in the first processing bath from the Example, Comparative Example-2 is obtained by removing the blocked polyisocyanate compound in the second processing bath,
Comparative example of the imperial edict 2 treatment bath without carbon black
I gave it a 5.

The results are also shown in Table 1.

In the present invention, polyester fibers treated with a first treatment bath containing an aqueous solution of a polyepoxide compound, and then treated with a second treatment bath containing resorcinol, formaldehyde, rubber latex, blocked polyisocyanate compound, and carbon black are flexible and have excellent fatigue resistance. , it can be seen that the rate of rubber adhesion to polyester fibers is excellent.

In addition, Examples 19 to 22 are Example 5 except that the blocked polyinsyanate compound was variously changed in Example 5.
The results are shown in Table 2.

Table 2

Claims (3)

[Claims] (1) A rubber reinforcing polyester fiber is treated with a first treatment bath containing an aqueous solution of a polyepoxide compound, and then treated with a second treatment bath containing resorcinol, formaldehyde, rubber latex, blocked polyisocyanate compound, and carbon black. Adhesion treatment method for polyester fibers for rubber reinforcement. (2) The method for adhesion treatment of polyester fibers for rubber reinforcement according to claim (1), wherein the first treatment bath contains 0.5 to 15.0% by weight of a polyepoxide compound. (3) The second treatment bath contains the resorcinol/formaldehyde/rubber latex mixture (X), the blocked polyinocyanate compound (Yl)j, and the carbon block fZ+ in a weight ratio (Xi: (Y) of 100; 5 to 100: 30
, ((xl + (yl): '100 at (Z)
: 0.3 to 10' and a ratio of 0:20.