JPH11315476A - Adhesion treatment of polyester fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a treatment process polyester fiber cords excellent in adhesion to the matrix rubber of a rubber composite and suitable for reinforcing power transmission belts so as to effect high durability thereof. SOLUTION: This treatment process comprises imparting a polyester fiber coated with an epoxy compound in the fiber manufacturing process with a 1st treatment liquor containing toluene diisocyanate dimer and vinyl-pyridine- styrene-butadiene rubber latex followed by heat treatment at 180-240 deg.C for 60-180 s, twisting the resultant polyester fiber into a twisted yarn which, in turn, is imparted with a 2nd treatment liquor comprising resorcinol-formalin- rubber latex (RFL) followed by heat treatment at 180-240 deg.C for 60-180 s.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for treating a polyester fiber cord, and more particularly, to a method for treating a polyester fiber cord which can be suitably used as a power transmission belt reinforcing cord.

[0002]

2. Description of the Related Art Polyester fiber cords generally have excellent properties such as strength, elasticity, dimensional stability, and heat resistance, so that tires, belts,
It is useful as an excellent reinforcing fiber for rubber composites such as hoses, and is expected to expand its applications.

[0003] Generally, reinforcing fibers for composites such as belts are used in the form of twisted cords. Important characteristics of the twisted cord include adhesion performance to matrix rubber, cord strength, balance between load elongation and dry heat shrinkage, heat shrinkage stress, and the like. Among these properties, adhesive performance, and
The cord strength greatly affects the load resistance and durability of the finished belt, and the balance between the load elongation and the dry heat shrinkage affects the dimensional stability (belt length) during belt molding. Furthermore, the heat shrinkage stress affects the dimensional change during belt running, and is closely related to the belt transmission efficiency. Therefore, there is a demand for a bonding technique and bonding processing conditions that balance these characteristics.

[0004] Regarding the bonding between the polyester fiber cord and the rubber matrix, various kinds of RFL adhesives have been proposed in the past (eg, JP-A-57-187238, JP-A-60-110980, JP-B-8-118). -2971). However, with these bonding techniques, the bonding performance as a reinforcing fiber cord of a power transmission belt that performs a bending motion with a large number of pulleys is insufficient, and at present, sufficient durability has not been obtained.

[0005] Therefore, in order to further improve the adhesive performance, treatment with a solvent-based treating agent containing a compound having a free isocyanate group has been mainly performed.
However, such a solvent-based treatment is more problematic than a water-based treatment in that the cost of waste liquid treatment is large and the working environment is deteriorated.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and an object of the present invention is to provide a method of treating a polyester fiber cord which has solved the above-mentioned problems of the prior art. Another object of the present invention is to provide a polyester fiber cord suitable for obtaining a power transmission belt having excellent adhesiveness to a matrix rubber and excellent durability.

[0007]

According to the present invention, a first treatment liquid containing a dimer of toluene diisocyanate and a vinylpyridine / styrene / butadiene rubber latex is applied to a polyester fiber to which an epoxy compound has been applied in a spinning process, After a heat treatment at 180 to 240 ° C. for 60 to 180 seconds, a second treatment liquid containing resorcinol, formalin and rubber latex (RFL) is applied in a twisted state, and a heat treatment is performed at a temperature of 180 to 240 ° C. for 60 to 180 seconds. In the method of bonding polyester fibers.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
As the polyester fiber used in the present invention, a fiber made of polyester whose repeating unit is substantially ethylene terephthalate is preferably used, but a fiber made of polyester such as polyethylene terephthalate obtained by copolymerizing a small amount of a third component is used. You can do it.

In the present invention, as the polyester fiber, a yarn made of a so-called epoxy pre-treated yarn to which an epoxy resin has been previously applied in a spinning step is used. That is, the epoxy pretreated yarn is obtained by adding an epoxy compound in advance to a yarn-forming oil agent to be applied to the polyester fiber in the yarn-making process. As the epoxy compound, known compounds can be used, but those containing a polyepoxide compound having at least two or more epoxy groups in one molecule are preferable, and among them, 0.2 g equivalent or more of epoxy group per 100 g is contained. Those using a glycidyl ether compound of a polyhydric alcohol are most preferably exemplified.

[0010] The polyester fiber may be used in the form of a cord before the treatment with the first treatment liquid (raw cord), and after the treatment with the first treatment liquid in a non-twisted state, the second fiber may be used.
It may be used in the form of a cord before the treatment with the treatment liquid.

The cord made of the polyester fiber is
It can be obtained by a known method. That is, by aligning a predetermined number of filaments made of the polyester fiber, performing a bottom twist on this, then adjusting the desired number of the fibers subjected to the bottom twist, by performing a top twist in a direction opposite to the bottom twist. can get. In this case, the number of twists of each can be determined arbitrarily, but the number of twists of the upper twist is often performed by applying a smaller number of twists than the number of twists of the lower twist.

In the present invention, a first bonding treatment is applied to the above-mentioned epoxy pre-treated yarn of polyester fiber or a cord formed from the same. The first treatment liquid used in the first adhesion treatment needs to contain a dimer of toluene diisocyanate. Such dimers of toluene diisocyanate are usually particulate solids,
It is used by dissolving sodium dialkyl sulfosuccinate in a solvent dissolved in water.

A predetermined amount of the solution is added to vinylpyridine / styrene / butadiene rubber latex to form a first treatment liquid. When the first treatment liquid does not contain this latex, or when it contains a latex different from the above-mentioned latex, the obtained polyester fiber cord becomes too hard, resulting in reduced durability or poor adhesion performance. Or become inadequate.

The concentration of the isocyanate compound contained in the first treatment liquid is preferably in the range of 0.1 to 5.0% by weight. The concentration of the vinyl pyridine / styrene / butadiene rubber latex is 1.
It can be used in the range of 2 to 8.5% by weight, and may be appropriately selected depending on the hardness required for the obtained polyester fiber cord. Further, the total solids concentration is between 2 and 20
%, Preferably in the range of 3 to 15% by weight.

The method of applying the first treatment liquid to the polyester fiber or its cord is not particularly limited, but usually, a dipping method is employed. A preferable example is one in which the amount of the active ingredient adhered to the first treatment liquid to the polyester fiber is controlled in a range of 1 to 2% by weight.

The polyester fiber or the cord thereof to which the first treatment liquid has been adhered is subjected to a heat treatment, and the temperature of the heat treatment is 180 to 240 ° C., more preferably 21 to 240 ° C.
The heat treatment is preferably performed in the range of 0 to 235 ° C., and the heat treatment time is preferably in the range of 60 to 180 seconds, more preferably 90 to 150 seconds. At the time of this heat treatment, the polyester fiber or its cord is preferably treated under tension, whereby the strength of the cord obtained can be improved. The tensile stress under tension is preferably exemplified by a heat treatment while applying a stretch in a stretch ratio of 2 to 4.5%, more preferably in a range of about 3.5 to 4.0%.

In the case of non-twisted yarn, the polyester fiber which has been subjected to the first bonding treatment is subjected to a predetermined twist to form a cord, which is then subjected to resorcinol-formalin rubber latex (RF
A second bonding treatment is performed using a second treatment liquid containing L).

The RFL used in the second adhesive treatment has a molar ratio (R / F) of resorcinol to formaldehyde of 1:
Those in the range of 0.1 to 1: 6.0 are preferably used, more preferably in the range of 1: 0.5 to 1: 4, and still more preferably in the range of 1: 0.6 to 1: 0. Novolak type condensate in the range of 0.9.

The compounding ratio (RF / L) of resorcinol-formalin (RF) and rubber latex (L) is in the range of 1: 1 to 1:15 in terms of solid weight ratio.
More preferably, those in the range of 1: 3 to 1:12 are exemplified. If the compounding ratio of the rubber latex is too high, the second
It is not preferable because the tackiness of the treatment liquid becomes extremely high, and the cohesive force of the adhesive film becomes too low, which adversely affects the adhesion. 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 resistance are liable to decrease, which is not preferable.

The type of the rubber latex is not particularly limited, but is the same as that of the first treatment liquid.
Those using butadiene latex are preferred. In addition,
When the dimer of toluene diisocyanate used in the first processing liquid is added as a crosslinking agent to the second processing liquid,
It is more preferable because the bonding performance is improved. In this case, the addition amount of the toluene diisocyanate is based on RFL.
The active ingredient may be contained in the range of 10 to 20% by weight.

After the second bonding treatment, a treatment liquid is applied to the polyester fiber cord. When the first bonding treatment is performed in a non-twisted state, the form of the cord is changed before the second bonding treatment. It is necessary to process it. The method of applying the second treatment liquid is not particularly limited as in the case of the first treatment liquid, and is performed by a known method, and is usually performed by an immersion method.

The amount of the effective component of the second treatment liquid is preferably in the range of 1 to 2% by weight based on the polyester fiber cord.

The polyester fiber cord to which the second treatment liquid has been attached in this manner is heated at a temperature of 150 to 180 ° C.
The cord is dried for 90-150 seconds in a state where it does not slack, and then subjected to a heat treatment.
As in the case of the heat treatment after application of the treatment liquid, a treatment performed in the temperature range of 180 to 240 ° C., more preferably in the temperature range of 210 to 240 ° C., is preferably exemplified.
Examples are those for 180 seconds, more preferably for 90 to 150 seconds. At this time, the polyester fiber cord has a relaxation rate of 0.1 in order to reduce the heat shrinkage.
It is preferable that the heat treatment is performed in a relaxed state of 5 to 1.5%, preferably about 1.0%.

[0024]

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. A rubber composite such as a belt reinforced with a cord has excellent dimensional stability, and has excellent power transmission and fatigue resistance. Therefore, the polyester fiber cord obtained by the present invention,
It is optimally used as a core wire cord of a wrapped V-belt.

Conventionally, isocyanate compounds have high reactivity and cannot be used as they are in aqueous treatment agents.
The terminal has been blocked and used as a blocked isocyanate, and the block has been released upon heating, and the treatment has been performed for the first time to exhibit the effect of the isocyanate. However, in the present invention, it is not necessary to perform such blocking at all, and the dimer is released by heating to act as a bifunctional isocyanate, thereby contributing to an improvement in adhesive performance. In addition, the block body is not released and does not pollute the working environment, which is extremely effective for preserving the working environment.

[0026]

Hereinafter, the present invention will be described in more detail by way of examples. In the examples, the cord strength, the cord peel adhesion strength, the pull-out adhesion strength, and the fatigue property (strength retention) were measured by the following methods.

(1) Cord strength Using an Instron 5565 type tensile tester (manufactured by Instron), using a 4D air chuck, a test length (cord length): 250 mm, a tensile speed: 100 m / min. The breaking strength was determined. The measurement was performed 10 times, and the average value was defined as a code strength: N.

(2) Cord Peeling Adhesive Strength This is the peeling adhesive strength between the treated cord and rubber. Seven cords are buried near the surface of the rubber sheet and placed in a steam vulcanizer into which steam at a temperature of 150 ° C. is injected. After holding for 20 minutes for vulcanization, the two cords at both ends are removed, and the remaining five cords are alternately removed, that is, three cords are simultaneously taken out of the rubber sheet, and at a speed of 200 mm / min. The force required for the peeling at the time of peeling was measured and indicated by N / 3.

(3) Pull-out adhesive strength Indicates the shear adhesive strength between the treated cord and the rubber. The cord is embedded in a rubber block and held in a steam vulcanizer injected with steam at a temperature of 150 ° C. for 20 minutes. Vulcanized,
Next, the cord was pulled out from the rubber block at a speed of 200 mm / min, and the force required for pulling out was measured and expressed in N / cm.

(4) Fatigue (Strength of Retention) A measure of fatigue resistance, using a belt-type fatigue tester.
Thickness: sandwich the cord between two 2mm rubber sheets,
It is pressurized with a pressing pressure of 50 kg / cm ² and vulcanized at a temperature of 150 ° C. for 20 minutes. The obtained sheet is 50 mm wide x
The sample was cut into a belt shape (sample) having a length of 500 mm, a load of 10 kg was applied to the sample, and the sample was attached to a roller having a diameter of 20 mm.
After reciprocating for 1 million times, the cord was taken out and the remaining strength was measured to determine the strength retention rate during fatigue.

Example 1 First, the first and second treatment liquids used as the adhesive treatment agents in the examples were prepared as follows.

<First treatment liquid> As a surfactant, neocor SW (sodium dialkyl sulfosuccinate; manufactured by Daiichi Kogyo Seiyaku Co., Ltd .; concentration: 30%): 18 g was added to 100 g of water, and the mixture was stirred well. Into the solution, dimer of toluene diisocyanate (US TSE
125 g of JSR0652 (vinyl pyridine / styrene / butadiene rubber latex; manufactured by Takeda Pharmaceutical Co., Ltd .; concentration: 40%) was added to a solution obtained by adding and dissolving 100 g of a fine powder having a concentration of 100% (manufactured by Sharp Corporation). Stir well, add 775 g of water to the mixture, and mix well to obtain a first treatment liquid.

<Second treatment liquid> Sumikanol 700S (resorcinol-formalin initial condensate, R / F = 1 / 0.6
(Molar ratio); manufactured by Sumitomo Chemical Co., Ltd .; concentration: 65%): 2
0.1 g and 426.7 g of water are stirred and mixed, and then 5.1 g of an aqueous sodium hydroxide solution (concentration: 10%), 14.5 g of an aqueous ammonia solution (concentration: 28%), and an aqueous formalin solution (concentration: 37%). %): 17.1 g is added, and the mixture is further slowly stirred and mixed. Next, JSR0652 (vinyl pyridine styrene butadiene rubber latex; manufactured by Takeda Pharmaceutical Co., Ltd .; concentration: 40%): 422.8 g
, And finally, 61.8 g of a solution (concentration: 50%) in which a dimer of toluene diisocyanate prepared in the same manner as that prepared in the first treatment liquid is dissolved, and the mixture is thoroughly stirred to obtain a second treatment liquid. After the adjustment, it is aged for 24 hours in an atmosphere at room temperature before use.

<Adhesion treatment> A polyester filament yarn (manufactured by Teijin Limited, intrinsic viscosity:
0.85, 1000 denier / 250 filament) epoxy pre-treated yarns are aligned and 15 T / 1 in the Z direction.
Apply 0 cm twist (primary twist). Next, three lower twisted yarns were aligned and the upper twist was performed in the S direction at 9T / 10 cm to obtain a raw cord of 9000 denier. The obtained raw cord was immersed in the first treatment liquid using a contribute treater (manufactured by CA Ritzler Co., Ltd., tire cord processing machine) and then stretched at a temperature of 235 ° C. for 150 seconds at a stretch ratio of 3.5%. Heat treatment was performed under the following conditions. Next, after immersing the first adhesive treatment cord in the second treatment liquid adjusted as described above, the cord is dried at a temperature of 170 ° C. for 150 seconds under a constant length,
Subsequently, heat treatment was performed at a temperature of 230 ° C. for 120 seconds under the condition of a relaxation rate of 0.5% to obtain an adhesive treatment code. In addition, the adhesion amount of each processing liquid was adjusted to be 1 to 2% by weight. The obtained polyester fiber cord is vulcanized using a NR / SBR rubber containing NR (natural rubber) as a main component at a temperature of 150 ° C. for 20 minutes in a steam vulcanizer into which steam is blown to form a rubber composite. I got a body. Table 1 shows the results obtained by measuring the cord strength, peel adhesion, pull-out adhesion, and strength retention after fatigue for the rubber composite.

Example 2, Comparative Examples 1-2 In Example 1, the kind of isocyanate in the first treatment liquid and the second
Resorcinol-formalin (R
A rubber composite was obtained in the same manner as in Example 1 except that the mixing ratio (RF / L) of F) and the rubber latex (L) was changed as shown in Table 1 (Example 2, Comparative Examples 1 to 4). 2). For these, cord strength, peel adhesion, pull-out adhesion,
The results of measuring the cord strength retention after fatigue are shown in Table 1.

[0036]

[Table 1]

As shown in Table 1, in Examples 1 and 2 in which a dimer of toluene diisocyanate was used as the isocyanate of the first treatment liquid, the above measured values showed all excellent values. In Comparative Examples 1 and 2, in which the dimer of toluene diisocyanate was not used as the isocyanate, the peel adhesion, the pull-out adhesion, and the strength retention of the cord after fatigue were particularly poor, and were not satisfactory.

Claims (1)

[Claims] 1. A first treatment liquid containing a dimer of toluene diisocyanate and a vinylpyridine / styrene / butadiene rubber latex is applied to a polyester fiber to which an epoxy compound has been added in a spinning process.
After a heat treatment at 40 ° C. for 60 to 180 seconds, a second treatment liquid containing resorcinol / formalin / rubber latex (RFL) is applied in a twisted state, and a temperature of 180 to 240 ° C. for 60 to 180 ° C.
A method for bonding polyester fibers, wherein the heat treatment is performed for 180 seconds.