JPS5838536B2 - Manufacturing method of polyester fiber material for rubber reinforcement - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a polyester fiber material having excellent adhesion to rubber.

More specifically, by modifying the fiber surface, no special treatment is required in the processing process, and sufficient adhesion to rubber can be achieved using the same adhesives conventionally used for rayon and nylon. This is an improved method for producing polyester fiber materials.

Traditionally, polyester fibers are used for tire cords, conveyor belts, etc. due to their strength, dimensional stability, heat resistance, water resistance, and chemical resistance.
■-Despite having excellent properties as a material for reinforcing rubber such as belts, it is necessary to use a special one-bath treatment or two-bath two-stage treatment for adhesion to rubber. Adhesion-related performance, quality, processing cost, etc.
It was in a disadvantageous situation compared to nylon, etc.

After that, in the fiber manufacturing process, one of the two bath treatments is applied, and after coding, it is a so-called pre-treated type yarn that can be treated with normal RFL (consisting of resorcin formaldehyde fiber and rubber latex). (pretreatment system) was developed, and its versatility as a rubber reinforcing material has increased significantly.

However, in recent years, as highways have been improved and cars have become larger, the quality level required for tires has significantly increased.
Therefore, a higher level of adhesion between the rubber and the reinforcing material is required, and it has become difficult to meet such requirements with conventional adhesive methods.

As a result of intensive research to meet such demands, the present inventors discovered a method for obtaining a polyester pretreatment system that has a significantly higher level and stable adhesiveness than conventional yarns, and arrived at the present invention.

That is, the present invention provides a polyester fiber material for reinforcing rubber, which is characterized in that an adhesive is applied to an undrawn polyester fiber after melt spinning, the fiber is heated and stretched, and then an adhesive is applied again and a relaxation heat treatment is performed. This is the manufacturing method.

The polyester in the present invention refers to any high molecular weight polyester made of glycols and dicarboxylic acids, particularly high molecular weight polyesters obtained from ethylene glycol and aromatic dicarboxylic acids, and a typical example is ethylene glycol. There is polyethylene terephthalate obtained from and terephthalic acid.

The adhesive used in the present invention can be selected from known adhesives, such as epoxy compounds and isocyanates.

Note that the adhesive referred to herein does not include resorcinol-formaldehyde-latex (RFL) adhesive.

The present invention involves the first step of applying an adhesive to undrawn polyester fibers after melt spinning and heating and stretching them (including the case where the adhesive is applied during the stretching process to complete the stretching process), and the subsequent process of applying an adhesive to the polyester fibers. The second step consists of applying an adhesive again to the stretched drawn yarn and subjecting it to relaxation heat treatment (including the case where the adhesive is applied during the relaxation heat treatment to complete the relaxation heat treatment).

The amount of adhesive applied in the first step is 0 to the fiber weight.
．． 0.05 to 0.5% by weight, and in the second step, 0.05 to 1.5% by weight based on the weight of the fibers.

Therefore, as a final product, the amount of adhesive applied is 0.
It is 10 to 2.0% by weight, preferably 0.20 to 1.0% by weight.

The method of application is not limited in any way; spinning oil,
It may be applied together with the drawing oil or separately.

Further, the types of adhesives used in the first step and the second step may be the same or different.

In the first step, the undrawn yarn is usually 200 to 350
℃ (non-contact state) and stretched 4 to 8 times.

In the second step, usually 1-10% at 180-260°C (contact state) or 250-400°C (non-contact state)
be made to relax.

Note that the relaxation heat treatment in the present invention includes relaxation heat treatment after a slight tension is applied in order to improve dimensional stability.

In the first step of the present invention, an adhesive such as an epoxy compound easily diffuses into the unstretched polyester fiber, and in this state, the adhesive receives the heat during stretching and is fixed, forming a strong bond. It is assumed that

However, as it is, the adhesive coating does not follow the change in surface area of the polyester during stretching, and therefore has insufficient affinity for the water-based RFL adhesive used in the subsequent process.

Therefore, in the second step, the adhesive is applied again and the adhesive is fixed to the polyester using the heat of relaxation heat setting.

This forms an adhesive layer that is strongly bonded to the polyester, and an adhesive layer that has a high affinity for the RFL adhesive through this adhesive. A processing system is obtained.

The present invention will be explained in detail with reference to Examples below.

All percentages in the examples are percentages by weight.

Example 1 Polyethylene terephthalate ([η)-0,89, measured at 35°C in orthochlorophenol] was melt-spun to form an aqueous dispersion of an epoxy compound (“NERolo” manufactured by Nagase Sangyo Co., Ltd.) consisting of glycidyl ether of glycerin. The yarn was applied using a conventional oiling roller, and then a spinning oil consisting of mineral oil and a nonionic activator was applied, and the yarn was wound up as an undrawn yarn.

(The birefringence Δn of this thread was 150×10′.

) This undrawn yarn (9000 denier, 250
The filament) is stretched 4.5 times in the first stage using a multi-stage drawing machine equipped with a slit heater, and then stretched 1.4 times between the next rollers, during which time the atmosphere of the slit heater is
The temperature was set at 00°C and the temperature was passed for about 1 second.

Thereafter, an epoxy aqueous dispersion having the same composition as that applied in the spinning process was applied using an oiling roller, and then heated at 320°C.
It was passed through a slit heater to relax it by 5%, passed through a cooling roller, and then rolled up.

The denier of this drawn yarn was 1500 de, and the total adhesion amount of adhesive and oil was 0.7%.

The breakdown of this was calculated by performing oiling separately, and it was found that the amount of epoxy deposited in the spinning process (first process) was 0.2
%, that of the second step was about 0.4%, and the oil agent applied in the spinning step was about 0.1%.

This yarn was made into a two-strand cord with 40 twists/10crrL (Z twist) and 40 twists/10cIrL (S twist), treated with RFL adhesive, heat treated, embedded in rubber, and then subjected to a peel test. carried out.

The peeling force was 4.5 kg/cord.

In the peel test, five cords were simultaneously peeled in a T-peel state, and the peeling force per cord was expressed at a tensile speed of 30 cm/m1yt.

Example 2 After spinning yarn in the same manner as in Example 1, the temperature of the slit heater during the relaxation heat treatment was raised to 350°C to obtain stronger adhesive strength, and after that, the oil agent (mainly the smoothing agent) that was reduced by volatilization was ) In order to compensate for this, an oil containing a high leveling agent mainly containing trioctyl trimellitate was applied and then removed.

The total adhesion amount of adhesive and oil was 1.5%.

The peel adhesion strength of this product was measured in the same manner as in Example 1 and was found to be 4.7 kg/cord.

Comparative Example 1 In the first step, only oil was applied, and in the second step, adhesive was applied, and the other steps were the same as in Example 1. The adhesive strength was as shown in Table 1. there were.

However, in case B, the amount of adhesive applied was increased so that the amount of applied adhesive in the final product was the same as that of Example 1.

Comparative Example 2 A method was adopted in which oil and adhesive were applied only in the first step and no adhesive was applied in the second step, and the other steps were as in Example 1.
The adhesive strength obtained in the same manner as above was as shown in Table 1.

However, in B, the amount of adhesive applied was increased so that the amount of applied adhesive in the final product was the same as that of Example 1.

From Table 1, it is clear that in the case of Comparative Examples 1 and 2, the present invention does not provide any adhesive strength.

Claims (1)

[Claims] 1. A method for producing a polyester fiber material for reinforcing rubber, which comprises applying an adhesive to an undrawn polyester yarn, heating and stretching it, and then applying an adhesive again and subjecting it to a relaxing heat treatment.