KR20110078152A - Method for producing polyester tire cords - Google Patents

Abstract

PURPOSE: A method of manufacturing polyester tire cord is provided to offer adhesive force sustain rate as to rubber of the polyester fiber and excellent fatigue resistance by exclusively using or mixing a silane compound at the time of exposure at a high temperature. CONSTITUTION: The method of manufacturing polyester tire cord is as follows. The silane compound has 100% weight, and a first processing liquid having 2.0 - 10.0% weight is manufactured. The polyester twisted cord is passed through in the dyeing liquid while adding a tensile force. The cord is passed through a processing liquid and is dried and heat-treated. Resorcinol formalin latex (RFL) liquid is a second processing liquid, and passes the heat-treated polyester cord. The cord is passed through the second processing liquid, and is dried and stabilized.

Description

Manufacturing method of polyester tire cord {Method for Producing Polyester Tire Cords}

The present invention relates to a method for producing a tire cord fiber by treating a silane compound with a polyester fiber with a primary treatment liquid, and according to the present invention improves the heat resistance and fatigue resistance of the tire cord, which is generated during high-speed tire running High performance tire cord can be manufactured to prevent the separation of rubber and fiber.

The present invention relates to an adhesive composition of a rubber reinforcing polyester, in particular an adhesive composition for improving the heat resistance to rubber upon exposure to high temperatures of the reinforcing fibers and polyester deepened rubber reinforcement treated with the composition (dipped) fiber.

Polyester fibers represented by polyethylene terephthalate (PET) have excellent physical properties such as high strength and high modulus of elasticity, and thus are used as rubber reinforcing fibers such as tires, hoses, and belts. However, since the surface of polyester fiber is relatively inert, the adhesive force with rubber | gum is insufficient, and the physical property of a polyester fiber cannot be fully exhibited.

For this reason, Japanese Patent Application Laid-Open No. 54-73994 provides a chemical treatment method for treating the surface of polyester fiber with many chemical agents, such as aliphatic epoxy compound and blocked isocyanate compound to give adhesion by applying highly reactive chemical agent. The so-called two-bath treatment method of processing by normal RFL is proposed. However, this patent shows a good initial adhesive strength, but when the rubber is exposed to high temperature, the heat resistant adhesive strength is significantly decreased, and also the coverage with the rubber is significantly reduced. In addition, Japanese Patent Application Laid-Open No. 10-46475 proposes a method in which an isocyanate compound and an aromatic epoxy compound blocked in RFL are added and treated in one bath. However, this patent has a disadvantage that the isocyanate compound is gelled by reacting with the RFL and the stability of the dip solution is poor. In addition, there is a disadvantage that the level of adhesion does not show satisfactory results.

Another method for treating polyester fibers is shown in US Pat. No. 3,234,067. This patent was treated with one bath of epoxy / isocyanate mixture followed by conventional RFL. However, this patent uses an excess of alkali compounds to increase the stability of the RFL. This alkali compound causes hydrolysis by alkali. In addition, the polyester fibers treated by these methods are inferior in adhesion with rubber at high temperatures, and the amount of adhesion must be excessive in order to obtain sufficient adhesion. However, if the amount of adhesion is increased, the dip fluid penetrates excessively into the fiber, and the stiffness of the fiber is increased, thereby reducing the fatigue resistance. In addition, the polyester fiber treated as described above causes a catalysis by an amine compound upon exposure to high temperature, resulting in degradation of fiber strength and adhesion to rubber at high temperature.

Therefore, the present invention was invented to solve the above problems, by using alone or mixed with a silane compound instead of a polyepoxide compound in the primary treatment solution, the adhesive strength retention rate and the high temperature of the polyester fiber rubber when exposed to high temperatures It is an object of the present invention to provide an adhesive composition for producing polyester fibers having excellent coverage with rubber and excellent fatigue resistance at the same time.

According to a preferred embodiment of the present invention, the method comprises the steps of preparing a primary treatment solution composed of blocked isocyanate and silane compound and comprising 2.0 to 10.0% by weight with respect to 100% by weight of silane compound, polyester twisted cord Passing through the dyeing solution while applying a tensile force, drying and heat-treating the cord passed through the treatment solution, passing the heat-treated polyester cord through the resorcinol formalin latex (RFL) solution, a secondary treatment solution Step, to provide a method for producing a polyester tire cord, characterized in that consisting of the step of drying and stabilizing the cord passed through the secondary treatment liquid.

According to another suitable embodiment of the present invention, there is provided a method for producing a polyester tire cord, wherein the silane compound of the primary treatment liquid is epoxy silane, amino silane, methacryl silane or a mixture thereof.

According to another suitable embodiment of the present invention, there is provided a radial pneumatic tire comprising a tire cord manufactured by the above method.

As described above, the polyester tire cord according to the present invention can express high heat resistance and rubber coverage and excellent fatigue resistance by treating the silane compound as a primary treatment liquid, thereby enabling the production of a high performance tire.

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

The polyester tire cord used in the present invention is a polyester fiber having high modulus and excellent form stability. However, polyester fibers are not sufficient in the development of adhesion, and also has the disadvantage that the adhesion and rubber coverage at a high temperature due to hydrolysis and amine decomposition by the water and amine compounds in the rubber component is significantly reduced. In the present invention, by using the silane compound in order to solve these disadvantages, it is possible to achieve the adhesion at high temperatures and excellent rubber coverage.

The silane compound of the present invention is described as follows.

In general, silane compounds are widely used as coupling agents for cross-linking organic and inorganic compounds. It is a compound having two reactivity properties in a molecule based on a silicon compound. Representative silane types include epoxy silane (I), methacryl silane (II), amino silane (III) and the like. In addition, it has excellent wettability and shows favorable properties in workability or production process due to low viscosity.

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In the primary treatment liquid of the present invention, the silane compound content is to be included 2.0 to 10.0% by weight, more preferably 3.0 to 7.0% by weight relative to 100% by weight pure water. If the content of the silane is 2.0 wt% or less, insufficient adhesion of the silane compound is not achieved, and in the case of 10.0 wt% or more, the rubber coverage due to the silicone material present in the silane compound is reduced, and the cost of the treatment liquid is produced. At the same time, an excessive increase is caused, and it is difficult to uniformly disperse the silane compound during the preparation of the treatment liquid.

In addition, the silane compound and the isocyanate compound blocked must be in the range of silane compound / isocyanate = 1 / 0.5 to 1/8 by weight. If this range is exceeded, not only sufficient adhesive force is exhibited, but also the rigidity is so high that fatigue resistance, which is one of the main characteristics of a tire cord, is reduced, resulting in inferior tire durability.

The polyester fiber prepared as described above can express high heat-resistant adhesiveness and rubber coverage and excellent fatigue resistance, thereby exhibiting a feature capable of producing a high performance tire.

Hereinafter, the structure and effect of the present invention will be described in more detail with specific examples and comparative examples, but these examples are only intended to more clearly understand the present invention, and are not intended to limit the scope of the present invention. In the comparative example and the Example, the following evaluation methods were utilized.

(a) cord pull test

Shear adhesion between the treated cord and rubber, which is placed in a rubber block with 150 ° 30 minutes, 50 kgf / cm 2 press pressure (initial value) or 170 ° 90 minutes, 50 kgf / cm 2 press pressure (heat resistance value) Vulcanize The cord is then tested by pulling the cord from the rubber block at a speed of 200 mm per minute, with the force required to pull in kg / cm.

(b) rubber coverage

As a measure of the adhesion of rubber to fibers, the cord peeled from the rubber was visually observed when the cord peeling adhesive force was measured, and the parts attached to the cord surface were visually judged to be A, B, C, D, It was evaluated by classifying it into 5 grades of E. Grade A refers to the case where more than 80% of the rubber is attached or the rubber peeling phenomenon occurs. Grade B is 60 to 80%, Grade C is 40 to 60%, Grade D is 20 to 40%, Grade E is 20% rubber The state of attachment is as follows. The grading was derived by averaging three judges independently.

(c) even with fatigue

After fatigue test using a Goodrich Disc Fatigue Tester which is commonly used for fatigue testing of tire cords, residual strength was measured and the fatigue resistance was compared. The fatigue test conditions were 120 ° C., 2500 RPM, and 10% compression. After fatigue test, the rubber was swelled by immersion in tetrachloroethylene solution for 24 hours, and the rubber and cord were separated to measure residual strength. The residual strength was measured using a conventional tensile strength tester after drying for 2 hours at 107 ° C.

[Examples 1 to 5]

An epoxy silane compound (Dow Corning Co. Z-6040) was prepared with a primary treatment solution of 3.0 wt% based on 100 wt% of pure water, and a silane compound / isocyanate = 1/4 in weight ratio. Secondary treatment solution was prepared by conventional RFL. 1,500 denier polyester fiber ply for tire cords (ply) of 37 ± 2.0 in the upper soft water and 37 ± 2.0 in the lower soft water, the yarn twisted cord is immersed in the first treatment liquid while applying a tension of 0.1 g / d. The resultant was dried at 160 ° C. for 2 minutes and heat-treated at 240 ° C. After the heat treatment process, the polyester cord was impregnated with the RFL adhesive solution, which is a secondary treatment solution, dried at 160 ° C. and stabilized at 240 ° C., thereby preparing a polyester fiber for tire cords.

The conditions and evaluation results of the examples are shown in Table 1 and Table 2.

[Comparative Examples 1 to 3]

Primary treatment solution containing 5.0 wt% of pure water and silane compound / isocyanate = 1/4 by weight of 100 wt% pure water using aliphatic epoxy (Nagase Chemtex, Japan, EX-614B) instead of silane compound in primary treatment solution Was prepared. Secondary treatment solution was prepared by conventional RFL. Drying and heat treatment temperatures are the same as in Examples. The evaluation results at this time are shown in Table 1 and Table 2.

TABLE 1

TABLE 2

As a result of the test results of Table 2, it can be seen that the tire (Example) according to the present invention has a superior heat resistance and heat coverage compared to Comparative Example 1 using an aliphatic epoxy as the first treatment liquid, thereby improving heat resistance. In addition, it can be seen that the effect is also excellent in terms of fatigue.

Claims (3)

Preparing a primary treatment liquid comprising a blocked isocyanate and a silane compound, the composition including 2.0 to 10.0 wt% of the silane compound with respect to 100 wt% of pure water; Passing a polyester twist cord through the dyeing solution while applying a tensile force; Drying and heat treating the cord having passed through the treatment liquid; Passing the heat treated polyester cord through a resorcinol formalin latex (RFL) solution, which is a secondary treatment solution; Method of producing a polyester tire cord, characterized in that consisting of the step of drying and stabilizing the cord passed through the secondary treatment liquid. The method of claim 1, The method for producing a polyester tire cord, wherein the silane compound of the primary treatment liquid is epoxy silane, amino silane, methacryl silane or a mixture thereof. Radial pneumatic tire, characterized in that it comprises a tire cord manufactured according to claim 1.