JP3231644B2 - Polyester fiber bonding method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for bonding polyester fibers which can be suitably used as a power transmission belt reinforcing cord. More specifically, the present invention relates to a method for bonding polyester fibers which is suitable for a core wire cord of a wrapped V-belt, has good adhesion to matrix rubber, and has excellent durability.

[0002]

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

[0003] In general, reinforcing fibers for composites such as belts are used in the form of so-called twisted cords which are twisted and bonded. An important property for this code is
The properties include adhesion to matrix rubber, cord strength, balance between load elongation and dry heat shrinkage, and heat shrinkage stress.

That is, the adhesive performance and the cord strength greatly affect the load-carrying performance and durability of the obtained belt, and the balance between the load elongation and the dry heat shrinkage ratio is determined by the dimensional stability at the time of forming the belt. Length). Further, the heat shrinkage stress affects the dimensional change during belt running and has a deep relationship with the transmission efficiency of the belt.

For this reason, there has been a demand for the development of adhesives and bonding treatment conditions that balance these characteristics.

As an adhesive between a polyester fiber cord and a rubber matrix, various kinds of resorcin, formalin and rubber latex (hereinafter referred to as RFL) adhesives have been proposed (for example, JP-A-57-1872).
No. 38, JP-A-60-110980 and JP-B-8-2971.

However, with these adhesives, the bonding performance of the transmission belt subjected to bending motion by a large number of pulleys as a reinforcing fiber cord is insufficient, and it is a reality that sufficient durability is not obtained.

In order to solve such a problem, it has been considered to impregnate the inside of the cord with an adhesive by using a solvent-based treating agent containing a compound having a free isocyanate group. It is inferior to water-based treatment in terms of waste liquid treatment cost and work environment.

Further, when forming a V-shaped belt, there is a step of turning over a cylindrical rubber sheet laminate reinforced with a fiber cord. In this step, if the adhesiveness of the fiber cord is insufficient, The laminate cannot retain its shape,
There is a risk of destruction.

In order to avoid this drawback, if the amount of the adhesive attached to the fiber cord is increased and the adhesiveness is increased, excess adhesive adheres to various guides attached to the yarn path of the fiber cord, As a result, spots may adhere to the fiber cord, thereby deteriorating the adhesive performance and, in turn, the durability of the belt.

[0011]

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

[0012]

The object of the present invention is to provide a polyester fiber comprising a polyepoxide compound containing two or more epoxy groups, a blocked polyisocyanate compound,
And a first treatment liquid containing vinyl pyridine / styrene / butadiene rubber latex and a temperature of 180 to 240 ° C.
After the heat treatment for 60 to 180 seconds, in the twisted cord state,
Resorcin, formalin and rubber latex (RFL)
At a temperature of 180 to 240 ° C.
After heat treatment for 0 to 180 seconds, a third
Apply the treatment liquid, and at a temperature of 140 to 170 ° C, 120 to 24
This is achieved by a polyester fiber bonding treatment method characterized by performing a heat treatment for 0 second.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The polyester fiber used in the present invention is preferably a fiber made of polyester whose repeating unit is substantially ethylene terephthalate, but other fibers such as polyethylene terephthalate obtained by copolymerizing a small amount of a third component. May be used.

In the present invention, a desired number of the yarns composed of the polyester fibers are arranged in a desired number, and at least a sub-twist is applied to form a twisted cord. More preferably,
The number of the twisted yarns is adjusted to a desired number, and the twisting in the direction opposite to the twisting is given. At this time, the number of twists of the lower twist is generally smaller than that of the next upper twist.

Next, the obtained raw cord is subjected to a first bonding process, a second bonding process, and a third bonding process described later.

Alternatively, a first bonding treatment is applied to a non-twisted polyester fiber yarn, the obtained treated yarn is twisted into a cord shape, and then a second bonding treatment and a third bonding treatment are performed. You may.

The first treatment liquid used in the first adhesion treatment of the present invention needs to contain a polyepoxide compound having at least two or more epoxy groups in one molecule. Particularly, a polyepoxide compound containing 0.2 g equivalent or more of an epoxy group per 100 g is preferable, and a polyglycidyl ether compound of a polyhydric alcohol is particularly preferable because it shows excellent performance.

Such a polyepoxide compound is usually dissolved in a small amount of a solvent and used as an emulsion or a solution using a known emulsifier, for example, sodium alkylbenzenesulfonate, sodium salt of dioctylsulfosuccinate, or the like.

At this time, an epoxy group curing reaction catalyst such as an amine curing agent or an imidazole curing agent may be used in combination.

It is necessary that the first treatment liquid contains a blocked polyisocyanate compound which is an addition compound of a polyisocyanate and a blocking agent such as oxime, phenol and caprolactam.

The mixing weight ratio (A / B) of the polyepoxide compound (A) and the blocked polyisocyanate compound (B) is suitably in the range of 0.25 to 1.5.

Further, the first treatment liquid contains vinyl pyridine
Styrene-butadiene rubber latex must be included.

When the latex is not contained, or when a latex different from the latex is contained, the obtained polyester fiber cord becomes too hard, and the durability is lowered or the adhesive performance is insufficient. It is not preferable.

In this case, it is preferable to use a vinylpyridine / styrene / butadiene rubber latex having a Mooney viscosity at 20 ° C. of 30 to 40 cps, since the effects of the present invention are remarkably exhibited.

The concentration of the polyepoxide compound in the first processing solution is suitably from 0.1 to 5.0% by weight. The concentration of vinyl pyridine / styrene / butadiene rubber latex may be appropriately selected within the range of 1.2 to 8.5% by weight depending on the hardness required for the obtained polyester fiber cord. Further, the total solid concentration is suitably 2 to 20% by weight, preferably 3 to 15% by weight.

As a method of applying the first treatment liquid to the polyester fiber, a conventionally known method can be arbitrarily adopted, but usually, an immersion method is employed.

It is desirable to control the amount of the active ingredient of the first treatment liquid adhered to the fiber cord in the range of 1 to 2% by weight.

The polyester fiber to which the first treatment liquid has been adhered has a temperature of 180 to 240 ° C., preferably 210 to 235.
Heat treatment is performed at a temperature of 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 is heat-treated while applying a tensile stress (a stretch rate of 2 to 4.5%, preferably about 3.5% stretch). preferable.

Next, the polyester fiber subjected to the first bonding treatment is subjected to a desired twist in the case of a non-twisted yarn, and then subjected to RF
An adhesive treatment is performed with a second treatment liquid containing L.

The RFL used here has a molar ratio of resorcinol to formaldehyde of 1: 0.1 to 1: 6, preferably 1: 0.5 to 1: 4.

The mixing ratio (RF / L) of resorcinol-formalin (RF) and rubber latex (L) is 1: 1 to 1:15, preferably 1: 3 to 1:15 in terms of solid content weight ratio.
A range of 12 is appropriate.

If the compounding 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 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,
Strength and fatigue are likely to decrease.

The type of rubber latex need not be particularly limited, but the same vinyl pyridine / styrene / butadiene latex as used in the first treatment liquid is preferred. It is more preferable to add a blocked polyisocyanate compound of about 1/5 weight to the weight of the solid content of the rubber latex as a cross-linking agent to the second treatment liquid because the adhesion performance is improved.

The method of applying the second treatment liquid is not particularly limited as in the case of the first treatment liquid, but usually a dipping method is employed. It is desirable to control the amount of the active ingredient adhered to the second treatment liquid in the range of 1 to 2% by weight.

The polyester fiber to which the second treatment liquid has been applied is dried at a temperature of 150 to 180 ° C. for 90 to 150 seconds in a state where the cord does not slack, and then dried at a temperature of 180 to 2
40 ° C, preferably 210-240 ° C, 60-180
The heat treatment is performed for seconds, preferably 90 to 150 seconds.

At this time, the polyester fiber cord has a relaxation rate of 0.5 to 1 to reduce the heat shrinkage.
It is preferable to perform a relaxation heat treatment while giving a relaxation of 5%, preferably about 1.0%.

The polyester fiber which has been subjected to the second bonding treatment is then subjected to R using a rubber latex suitable for the rubber to be adhered.
A third bonding process is performed with a third processing liquid containing FL as a main component. The preferred rubber latex at this time is vinyl pyridine used in the first and second treatment agents.
Styrene-butadiene latex is exemplified.

The resorcinol-formalin (RF) used here has an R / F molar ratio of 1 / 0.6 to 1/1,
In particular, it is preferably in the range of 1 / 0.7 to 1 / 0.9.

That is, it is important that the RF resin be a linear novolak type. If the amount of formalin used increases, the third adhesive film cross-links three-dimensionally, so that the compatibility with the matrix rubber decreases. And it is difficult to obtain sufficient adhesive performance.

The weight ratio (RF / L) of resorcinol-formalin (RF) to rubber latex (L) is 1 /
A range of 2 to 1/20, preferably 1/4 to 1/18 is appropriate.

The method of applying the third treatment liquid is not particularly limited, but usually, an immersion method is employed.

It is desirable that the amount of the active ingredient adhered to the third treatment liquid is controlled in the range of 1 to 4% by weight.

The polyester fiber to which the third treatment liquid has been applied is subjected to a heat treatment at 140 to 170 ° C., which is lower than the heat treatment temperature after the application of the first treatment liquid and the second treatment liquid, for 120 to 240 seconds. It is important to make the adhesive film in a semi-cured state.

By doing so, the adhesive film made of the third processing liquid exhibits excellent compatibility with both the adhesive film made of the second processing liquid and the matrix rubber, and the uncured vulcanized film is formed when the belt is formed. While having favorable tackiness with rubber, the third adhesive film is sufficiently cured at the time of vulcanization, so that strong adhesive performance can be exhibited.

In this third treatment liquid, an aqueous dispersion of carbon black prepared by a usual method is added in an amount of 0.5 to 10% by weight based on RFL to prevent photodeterioration due to ultraviolet rays. Is preferred.

[0047]

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 peel adhesive strength, the pull-out adhesive strength, the fatigue property (strength retention), and the Mooney viscosity were measured by the following methods.

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

(2) Cord peeling adhesive strength Seven cords are buried near the surface of the rubber sheet, and 50 kg /
Vulcanization at a temperature of 150 ° C. for 20 minutes while applying a pressing pressure of ² cm ² , then removing two cords at both ends, and removing three cords excluding the center and both ends of the remaining five cords. The cord is simultaneously removed from the rubber sheet for 200
The force required to peel at a speed of mm / min was measured, and the value was divided by 3 to obtain the value of the peel adhesive force.

(3) Pull-out adhesive strength A cord is embedded in a rubber block for a predetermined length, and a 50 kg /
vulcanizing at a temperature of 150 ° C. for 20 minutes while applying a pressing pressure of ² cm,
/ Min at a speed of 1 min.
It was indicated by the pull-out adhesive strength per m.

(4) 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 pressing force of 50 kg / cm ² is applied at a temperature of 150 ° C. for 20 minutes. Vulcanize for a minute.

The obtained sheet is 50 mm wide × 500 mm
Cut into a long belt shape, apply a load of 25 kg to the sample, attach it to a roller having a diameter of 20 mm, and repeat 500,000 reciprocating motions at 120 rpm in an atmosphere of 120 ° C. The strength retention after fatigue was measured.

(5) Mooney viscosity The Mooney viscosity was measured by a method specified in JIS K6300 and ASTM D1646. The measurement atmosphere was 20 ° C.
Met.

[Example 1] First, an adhesive treatment agent was prepared as follows. Specifically, 35.1 g of Denacol EX-611 (sorbitol diglycidyl ether; manufactured by Nagase Kasei Co., Ltd.) was added to Neocol SW-3 as a surfactant.
0 (dioctyl sulfosuccinate sodium salt; manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd .; concentration: 30%) is added, and the mixture is stirred well and dissolved.

Then, while stirring 694.7 g of water at a high speed, the epoxy solution is slowly added and dispersed. Then, 211.2 g of S-3 (aqueous dispersion of blocked isocyanate; manufactured by Meisei Chemical Co., Ltd .; concentration: 25%) is slowly added and dispersed. Next, PLIOCORD V
P-106 (vinyl pyridine / styrene / butadiene rubber latex; manufactured by Goodyear Corporation, concentration: 40%,
30 g of Mooney viscosity 65) is added, and the mixture is stirred well to obtain a first treatment liquid.

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. After mixing, 5.1 g of aqueous sodium hydroxide solution (concentration 10%), 14.5 g of aqueous ammonia solution (concentration 28%), and aqueous formalin solution (concentration 3
(7%) 17.1 g is added, and the mixture is further slowly stirred and mixed.

Next, PLIOCORD VP-106 was added to 4
22.8 g was added, and finally DM-6011 (blocked polyisocyanate compound; manufactured by Meisei Chemical Industry Co., Ltd.
(Concentration 33%) 93.7 g was added, and the mixture was stirred well to obtain a second treatment liquid. The treatment liquid is used after aging for 24 hours in a room temperature atmosphere.

Next, 5.5 g of Sumikanol 700S was added.
And 758.7 g of water were stirred and mixed, and 0.8 g of an aqueous formalin solution (concentration: 37%), PLIOCORD VP-1
Add 275 g of No.06 and mix well to obtain a third treatment liquid.

Three 1000 denier / 250 filament polyester yarns (intrinsic viscosity 0.85; manufactured by Teijin Limited) are aligned and ply-twisted in the Z direction at 15 T / 10 cm. Next, three of the lower twisted yarns were aligned, and the upper twist was 9T / 10 cm in the S direction to obtain a raw cord.

The raw cord thus obtained was immersed in the first treatment liquid using a computer treater (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%. did.

Next, it is immersed in the second processing solution, dried at 170 ° C. under a constant length for 150 seconds, and subsequently subjected to a heat treatment at 230 ° C. for 120 seconds under a 0.5% relaxation rate.
After immersion in the above third treatment solution, the solution
A heat treatment was performed for 0 seconds to obtain a prepreg cord.
The amount of each processing solution was adjusted to be 1 to 2% by weight.

[Example 2] In Example 1, vinyl pyridine / styrene / butadiene rubber latex was replaced with Nippol 2518FS (vinyl pyridine / styrene / butadiene rubber latex manufactured by Zeon Corporation; concentration: 40).
% And Mooney viscosity 35), except that the cord was obtained in the same manner as in Example 1.

Embodiments 3 and 4 In Embodiment 2, the first
Except that the weight ratio (Ep / Iso) of the polyepoxide compound and the blocked polyisocyanate compound of the processing solution, RF / L of the second processing solution and R / F of the third processing solution were changed as shown in Table 1. The code was obtained in the same manner as in Example 2.

[0064]

Comparative Example 1 In Example 2, an acrylic rubber latex (manufactured by Zeon Corporation; Nippol 854E; concentration of 4) was used in place of vinylpyridine / styrene / butadiene rubber latex.
0%) to obtain a cord in the same manner as in Example 2. Table 1 shows the results of measuring the cord strength, peel adhesive strength, pull-out adhesive strength, and post-fatigue cord strength retention of the obtained cords.

[0066]

[Table 1]

[0067]

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. When forming a belt reinforced with cords, there is no peeling of cords in the process of reversing the inner and outer layers, and there is no decrease in cord physical properties and adhesion performance with rubber, and the obtained rubber composite has dimensional stability. It has excellent power transmission and fatigue resistance.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI // D06M 101: 32 D06M 101: 32

Claims (3)

(57) [Claims] 1. A polyester fiber is provided with a first treatment liquid containing a polyepoxide compound containing two or more epoxy groups, a blocked polyisocyanate compound, and a vinylpyridine / styrene / butadiene rubber latex at a temperature of 180 to 240 ° C. After the heat treatment for 60 to 180 seconds, a second treatment liquid containing resorcin, formalin and rubber latex (RFL) is applied in a twisted cord state, and the temperature is adjusted to 18
After heat treatment at 0 to 240 ° C. for 60 to 180 seconds,
A third treatment liquid containing RFL is applied, and a temperature of 140 to 170
A method for bonding polyester fibers, wherein heat treatment is performed at 120 ° C. for 120 to 240 seconds. 2. The vinyl pyridine / styrene / butadiene rubber latex having a Mooney viscosity at 20 ° C. of 30 to 30.
2. The polyester fiber connection according to claim 1, which is 40 cps.
Dressing method. 3. The RFL of the third treatment liquid has a resorcin / formalin molar ratio (R / F) of 1 / 0.7 to 1/0.
9, the weight ratio (RF / L) of the novolak-type condensate (RF) and the rubber latex (L) is 1/4 to 1/1.
The method for bonding polyester fibers according to claim 1, which is 8.