JP2000355873A - Treatment of polyester fiber cord - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a polyester fiber cord suitable for providing a rubber composite excellent in adhesion to a matrix rubber even if the composite is directly exposed to steam and also good in durability. SOLUTION: The first treating liquid comprising a water dispersion of a glycidyl ether compound and a diisocyanate dimer compound, in the proportion of 0.5-1.5 wt.% expressed in terms of active ingredients based on the weight of fiber is imparted to a polyester fiber having an epoxy compound previously imparted thereto at a fiber-forming step, and in an untwisted state or a twisted cord state, and the resultant fiber is heat-treated at 180-240 deg.C for 60-180 sec. The heat-treated fiber is twisted when the fiber is in the untwisted state. The second treating liquid containing resorcin-formalin-rubber latex(RFL) is imparted to the resultant fiber, and the obtained fiber is heat-treated at 180-240 deg.C for 60-180 sec to provide the objective polyester fiber cord.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating a polyester fiber cord which can be suitably used as a reinforcing cord for a power transmission belt or the like. More specifically, the present invention is suitable as a core wire cord of a wrapped V-belt, and has a good adhesiveness to a matrix rubber and a high durability even when exposed to leaked steam particularly when molded by steam vulcanization. The invention also relates to an excellent polyester fiber cord processing method.

[0002]

2. Description of the Related Art Polyester fiber cords generally have excellent properties such as strength, elastic modulus, dimensional stability, and heat resistance, so that rubber composites such as tires, belts, and hoses used under severe conditions are used. It is useful as an excellent reinforcing fiber, and is expected to expand its use.

Generally, reinforcing fibers for rubber composites such as belts are used in the form of twisted cords. Important properties for this cord include adhesion to matrix rubber, cord strength, balance between load elongation and dry heat shrinkage, heat shrinkage stress, and the like. For example, in the case of a belt, among these properties, the adhesive performance and the cord strength greatly contribute to the load resistance and durability of the finished belt, and the balance between the load elongation and the dry heat shrinkage ratio is dimensional stability during belt molding. It affects the performance (belt length). Further, the heat shrinkage stress affects the dimensional change during the running of the belt, and is closely related to the transmission efficiency of the belt. Therefore, there is a demand for a bonding technique and bonding processing conditions that balance these characteristics.

[0004] Regarding the adhesion between the polyester fiber cord and the rubber matrix, various kinds of resorcinol-formalin latex adhesives (RFL adhesives) have been conventionally proposed (for example, JP-A-57-187238, JP-A-57-238238). No. 60-110980, Japanese Patent Publication No. 8-2971, etc.). However, in general, when a belt is formed using a polyester fiber cord as a core wire, the belt is often formed by a steam vulcanization method, and steam is not directly sprayed on rubber / fiber material. They may be directly exposed to steam leaking from gaps. Therefore, in the fiber cord obtained by the method proposed above, several percent of the formed belt may have poor adhesion. That is, in the conventional bonding technology, the bonding performance of the power transmission belt that performs bending motion with a large number of pulleys, particularly as a reinforcing fiber cable cord, is insufficient, and it is a reality that sufficient durability is not obtained. Therefore, treatment with a solvent-based treating agent containing a compound having a free isocyanate group has been mainly performed for the purpose of improving the adhesive performance. However, such a solvent-based treatment is significantly inferior to a water-based treatment in terms of waste liquid treatment cost and work environment.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide excellent adhesiveness to a matrix rubber even when directly exposed to steam, and to have high durability. An object of the present invention is to provide a method for treating a polyester fiber cord which is suitable for obtaining a good rubber composite, particularly a power transmission belt.

[0006]

Means for Solving the Problems The object of the present invention is to provide:
"A first treatment liquid comprising an aqueous dispersion of a glycidyl ether compound and a diisocyanate dimer compound in a non-twisted state or a twisted cord state on a polyester fiber to which an epoxy compound has been added in advance in a spinning stage, and a fiber weight in terms of the effective component. 0.5 to 1.5% by weight with respect to the temperature of 180
After heat treatment at ~ 240 ° C for 60 to 180 seconds, twisting is applied to non-twisted yarn, then resorcinol / formalin /
Applying a second processing liquid containing rubber latex (RFL);
A method for treating a polyester fiber cord, comprising performing a heat treatment at a temperature of 180 to 240 ° C. for 60 to 180 seconds. Is achieved.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The polyester fiber in the present invention is preferably a fiber composed of a polyester whose repeating unit is substantially ethylene terephthalate, but other polyesters such as polyethylene terephthalate obtained by copolymerizing a small amount of a third component. Fibers consisting of In the present invention, a so-called epoxy pre-treated yarn in which epoxy is previously applied to the polyester fiber in a yarn-making step is used.

In the present invention, a first bonding process and a second bonding process, which will be described later, are performed while the pre-processed yarn remains untwisted or formed into a twisted cord. Here, the twisted cord is manufactured by a conventionally known method. For example, the yarns composed of the pre-processed yarns are arranged in a desired number, and the first twist is applied.
Although the number of twists is arbitrary, it is common to apply a smaller number of twists than the next twist. Next, the desired number of fibers that have been twisted are adjusted, and a twisting cord (raw cord) is formed by giving an upper twist in a direction opposite to the twisting.

In the present invention, first, a first bonding treatment is applied to the obtained raw cord or non-twisted polyester fiber yarn.

The first treatment liquid used in the first adhesion treatment needs to contain a diisocyanate dimer compound and a glycidyl ether compound at the same time. Examples of the diisocyanate dimer compound include tolylene diisocyanate dimer, diphenylmethane diisocyanate dimer, and meta-xylylene diisocyanate dimer. These are usually fine solid particles, and are used as an aqueous dispersion in which a dispersant such as dialkylsulfosuccinate sodium salt is dissolved using a solution in water. On the other hand, since many glycidyl ether compounds do not disperse in water as they are, an aqueous dispersion in which a dispersant such as dialkyl sulfosuccinate sodium salt is similarly dispersed in water (in the case of water solubility, Aqueous solution).

At this time, it is preferable to add a small amount of a thickener, in particular, xantham gum, for the purpose of improving the uniform dispersibility of the diisocyanate dimer compound and the uniform adhesion of the treatment liquid. When a thickener is not used in combination, the viscosity of the first treatment liquid becomes too low, and the fine particles of the diisocyanate dimer are likely to precipitate in the treatment liquid. However, it becomes difficult to uniformly apply the treatment liquid to a cord or the like, and the adhesive strength is reduced or the dispersion is liable to occur. As a result, in order to stably achieve a sufficient adhesive strength, for example, the amount of adhesion must be increased, which is not preferable in terms of cost.

The weight ratio (EP / DI) of the glycidyl ether compound (EP) to the diisocyanate dimer compound (DI) in the first treatment liquid is from 10/90 to 30/7.
The range of 0 (weight ratio of active ingredient) is appropriate. If the compounding weight ratio is out of this range, the adhesiveness tends to decrease and the fatigue (durability) tends to decrease. The first processing liquid may contain other processing agent components as long as the object of the present invention is not impaired, but it is preferable that the first processing liquid does not substantially contain rubber latex.

The concentration of the diisocyanate dimer compound and the glycidyl ether compound in the first treatment liquid is not particularly limited, but is preferably 0.1 to 10.0% by weight, particularly 2 to 7% by weight in total. The method of applying the first treatment liquid to a non-twisted polyester fiber or twisted cord is optional, but usually a dipping method is employed. It is necessary to control the amount of adhesion of the first treatment liquid in terms of solid content (active ingredient) in the range of 0.5 to 1.5% by weight with respect to the fiber weight. After adhering the first treatment liquid, heat treatment is performed at 180 to 240 ° C., preferably 210 to 235 ° C., for 60 to 180 seconds, preferably 90 to 150 seconds. At this time, in order to improve the strength of the obtained cord, the polyester fiber or the twisted cord is stretched while applying a tensile stress (with a stretch ratio of 1 to 4.5%, preferably about 2.0%). ) Heat treatment is preferred.

[0014] In the case of non-twisted yarn, the polyester fiber subjected to the first bonding treatment is subjected to a desired twist, and then the second fiber containing resorcinol-formalin rubber latex (RFL) is used.
A second bonding process is performed with a processing liquid. RF used here
L may be one generally used for rubber material processing.
However, if the mixing ratio of the rubber latex is too high, the tackiness of the second treatment liquid becomes extremely high, and the cohesive force of the adhesive film becomes too low, so that the adhesiveness of the obtained fiber cord tends to be adversely affected. Conversely, if the mixing ratio of the rubber latex is too low, the obtained polyester fiber cord tends to be hard, and the strength and fatigue properties are liable to decrease. Therefore, the weight ratio between the resorcinol-formalin condensate and the rubber latex is 1/1 to 1/15, especially 1/5 to 1/15 for the former / the latter.
A range of 15 (weight ratio of solid content) is appropriate.

The type of the rubber latex need not be particularly limited. Further, when a blocked polyisocyanate (for example, diphenylmethane diisocyanate blocked with ε-caprolactam) is added as a cross-linking agent to the second treatment liquid in an amount of 10 to 20% by weight based on the amount of the RFL active ingredient, the adhesive performance is improved. It is more preferable because it improves.

The method of applying the second treatment liquid is not particularly limited as in the case of the first treatment liquid, but usually an immersion method is employed. It is desirable to control the amount of the active ingredient (in terms of solid content) attached to the second treatment liquid in the range of 1.0 to 3.0% by weight based on the weight of the fiber. The polyester fiber cord to which the second treatment liquid has been adhered has a temperature of 150 to 180 ° C.
For 0-150 seconds, let the cord dry without sagging,
Then, at a temperature of 180 to 240 ° C., preferably 210 to 24
Heat treatment is performed at 0 ° C. for 60 to 180 seconds, preferably 90 to 150 seconds. At this time, the polyester fiber cord, in order to reduce the heat shrinkage of the resulting treatment cord,
The relaxation rate is 0 to 1.5%, preferably 0.2 to 0.
It is preferable to perform the heat treatment for relaxation while giving about 5% relaxation.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to practical examples. In the examples, the cord strength, the cord peeling adhesive strength, the pull-out adhesive strength and the fatigue property (strength retention) were measured by the following methods.

<Cord Strength> Using a 4D air chuck, a test length (cord length) of 250 mm was taken using an Instron 5565 type tensile tester (manufactured by Instron).
The breaking strength was determined at a tensile speed of 300 mm / min. 10
Times, and the average value was taken as the code strength.

<Cord Peeling Adhesive Strength> This shows the peeling adhesive strength between the treated cord and the rubber. Seven cords were buried near the surface of the rubber sheet, and held in a steam vulcanizer into which steam at a temperature of 150 ° C. had been injected for 20 minutes to be vulcanized. Next, the two cords at both ends were removed, and the remaining five cords were simultaneously stripped from the rubber sheet at a speed of 200 mm / min. The power (N) required for peeling was measured and indicated as N / 5 cords (N / 5C). .

<Pull-out adhesive force> It shows the shear adhesive force between the treated cord and the rubber. The cord was embedded in a rubber block, held in a steam vulcanizer into which steam at a temperature of 150 ° C. was injected, and vulcanized for 20 minutes. Next, the cord was pulled out from the rubber block at a speed of 200 mm / min, and the power (N) required for the drawing was measured and indicated in N / cm.

<Fatigue (Strength of retention)> Using a belt-type fatigue tester, a cord is sandwiched between two rubber sheets having a thickness of 2 mm, and a pressure of 50 kg / cm ² is applied under a pressure of 150 ° C. for 20 minutes. Vulcanize. 50 sheets obtained
The sample was cut into a belt shape having a width of 500 mm and a length of 500 mm. A load of 10 kg was applied to the sample, and the sample was mounted on a roller having a diameter of 20 mm. The remaining strength was measured, and the strength retention during fatigue was determined.

Example 1 First, the adhesive treatment agent was adjusted as follows. That is, Neocol S as a surfactant
2 g of W (sodium dialkyl sulfosuccinate: manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., concentration: 30%) is added to 75 g of water, and 0.12 g of xanthogum powder is added to a well-mixed solution, followed by further stirring. There, tolylene diisocyanate dimer (made by TSE USA, fine powder,
25 g of trade name Thanecure T9 (concentration: 100%) was added and mixed well to obtain a 25% mixed solution. Next, 25 g of a glycidyl ether compound (Denacol EX314, manufactured by Nagase Kasei Kogyo Co., Ltd., 100% concentration) was taken, and 75 g of water was used as a surfactant as a surfactant in Neocol SW (sodium dialkyl sulfosuccinate: manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) (30%) in a solution containing 1.5 g. These are mixed so as to be 70 parts by weight of the isocyanate dimer compound and 30 parts by weight of the glycidyl ether compound, and further diluted 5 times to obtain a first treatment liquid having a concentration of 5%.

Further, 20.1 g of Sumikanol 700S (resorcinol-formalin initial condensate, R / F = 1 / 0.6 (molar ratio), manufactured by Sumitomo Chemical Co., Ltd., concentration: 65%) and 426.7 g of water were stirred. Then, 5.1 g of sodium hydroxide aqueous solution (concentration 10%), 14.5 g of ammonia aqueous solution (concentration 28%), and formalin aqueous solution (concentration 3
(7%) 17.1 g is further added and further slowly stirred and mixed. Next, JSR0652 (vinyl pyridine styrene
Butadiene rubber latex: manufactured by Takeda Pharmaceutical Co., Ltd.
(Concentration 40%) 422.8 g was added, and finally an aqueous dispersion of diphenylmethane diisocyanate blocked with ε-caprolactam (manufactured by EMS, trade name Grilbon)
(d, concentration: 50%), 61.8 g, and mix well to obtain a second treatment liquid. After the adjustment, it is aged for 24 hours in a room temperature atmosphere and used.

A polyglycidyl ether compound was previously added to the yarn-forming oil in the yarn-making process, and three 1000-denier / 250-filament epoxy-pretreated polyester filaments (intrinsic viscosity 0.85; Teijin Limited) were aligned. And a twist of 15T / 10 cm in the Z direction. Then, three strands of this twisted yarn are aligned and 9T in the S direction.
By applying a / 10 cm upper twist, a raw cord of 9000 denier was obtained. The obtained raw cord was immersed in the first treatment liquid using a contributor (tire code processing machine manufactured by CA Ritzler Co., Ltd.) and then heat-treated at 235 ° C. for 150 seconds with a stretch ratio of 3.5%.

Next, after being immersed in the second treatment liquid, it is dried at 170 ° C. under a constant length for 150 seconds, and subsequently subjected to a heat treatment at 230 ° C. under a relaxation rate of 0.5% for 120 seconds.
An adhesive treatment code was obtained. In addition, the amount of each processing solution adhered is 1 to
It was adjusted to be 2% by weight. The obtained polyester fiber cord was converted into NR / natural rubber (NR) /
Using SBR rubber, vulcanization was performed at 150 ° C. for 20 minutes in a steam vulcanizer into which steam was blown to obtain a rubber composite.

[Examples 2 to 3, Comparative Example 1] In Example 1, the mixing weight ratio of diisocyanate dimer and glycidyl ether (the ratio of active ingredients) in the first treatment liquid and the RF / L of the second treatment liquid were shown. Example 1 except for the change as described in 1.
And a rubber composite was obtained. Table 1 shows the results of measuring the cord strength, peel adhesion strength, pull-out adhesion strength, and cord strength retention after fatigue for these, together with Example 1.

[0027]

[Table 1]

[0028]

Industrial Applicability The polyester fiber cord obtained by the method of the present invention maintains the excellent mechanical properties of polyester fiber such as high strength, and has excellent adhesion to the matrix rubber of the rubber composite. Rubber composites such as belts reinforced with cords have excellent dimensional stability, and have excellent power transmission and fatigue resistance.

Conventionally, isocyanate compounds have high reactivity and cannot be used as such in aqueous treatment agents as they are.
A mechanism is adopted in which the isocyanate group is blocked, and the blocking agent is released upon heating to exert the effect of the isocyanate. However, in the present invention, the diisocyanate dimer is decomposed into monomers by heating and acts as free diisocyanate, so that good adhesion performance can be obtained without blocking.

Claims (4)

[Claims] 1. A first treatment liquid comprising a water dispersion of a glycidyl ether compound and a diisocyanate dimer compound in an untwisted state or in a twisted cord state on a polyester fiber to which an epoxy compound has been previously imparted in a spinning stage, with the active ingredient 0.5 to 1.5% by weight based on the weight of the fiber, heat-treated at a temperature of 180 to 240 ° C. for 60 to 180 seconds, and then twisted the non-twisted yarn, and then resorcinol / formalin / rubber latex A method for treating a polyester fiber cord, comprising applying a second treatment liquid containing (RFL) and performing a heat treatment at a temperature of 180 to 240 ° C for 60 to 180 seconds. 2. The method for treating a polyester fiber cord according to claim 1, wherein the diisocyanate dimer compound is a tolylene diisocyanate dimer. 3. The active ingredient weight ratio of the glycidyl ether compound to the diisocyanate dimer compound is 30/70.
The method for treating a polyester fiber cord according to claim 1 or 2, wherein the ratio is from 10 to 90/90. 4. The RFL contained in the second treatment liquid has a resorcin-formalin condensate (RF) and a rubber latex (L) having an active ingredient weight ratio (RF / L) of 1/5 to 1: 1.
/ 15, and the second treatment liquid contains 10% of the blocked polyisocyanate compound based on the weight of the RFL active ingredient.
The method for treating a polyester fiber cord according to claim 1, which is contained in an amount of from 20 to 20% by weight.