KR20120089898A - Method for producing polyethylene naphthalate tire cords - Google Patents

Abstract

PURPOSE: A method for fabricating a polyethylene naphthalate tire cord is provided to obtain the tire cord with excellent adhesion at high temperature and fatigue resistance. CONSTITUTION: A method for fabricating a polyethylene naphthalate tire cord comprises: a step of mixing 70-80 parts by weight of emulsifier, 10-20 parts by weight of epoxy silane, 0-15 parts by weight of methacryl silane, and 1-7 parts by weight of aromatic epoxy resin to prepare a silane-epoxy mixture solution; a step of treating polyethylenenaphthalate fibers with the silane-epoxy mixture solution; a step of twisting and weaving the polyethylene polyethylenenaphthalate fibers to prepare a grey fabric; a step of drying the grey fabric and applying tension to the grey fabric to prepare a polyethylenenaphthalate cord; a step of passing the polyethylenenaphthalate cord through an RFL adhesive solution; and a step of drying and stabilizing the cord.

Description

Method for producing polyethylene naphthalate tire cords {Method for Producing Polyethylene naphthalate Tire Cords}

The present invention relates to a method for producing polyethylene naphthalate fibers for tire cords by treating the surface of polyethylene naphthalate fibers, and provides reactivity to the surface of polyethylene naphthalate fibers that are not reactive to improve adhesion between rubber and polyethylene naphthalate tire cords. Polyethylene naphthalate fiber for tire cords, which can increase the fatigue resistance by introducing an aromatic epoxy resin having high thermal stability and having high fatigue resistance, and by using a reactive polyethylene naphthalate fiber It relates to a manufacturing method.

Tire cord fibers, typically represented by polyester terephthalate, have rubber composites, such as tires, belts or hoses, because they have excellent mechanical strength, modulus of elasticity, dimensional stability and heat resistance, which are important properties for rubber reinforcements. It is widely used as a reinforcing material for back. However, there has been a need for higher performance reinforcement materials due to the high performance of automobiles, the development of driving roads, and the severe use of rubber composite materials. Polyethylenelyphthalate naphthalate (Polyethlyene naphthalate) fiber has a repeating unit combined with naphthalene instead of benzene in the polyester fiber, it has excellent dimensional stability, heat resistance, mechanical strength than the polyester material is considered to be a high performance rubber reinforcement. However, since polyester naphthalate fibers, like polyester fibers, have poor surface adhesion due to their inert surface, they have been studied for a long time to improve the adhesion of fibers to rubber by treating epoxy and diisocyanate compounds on the surface of the fibers. come.

In the case of adhesives based on epoxy and diisocyanate compounds, polyethylene naphthalate fibers are treated with a primary treatment liquid consisting of a mixed solution of diisocyanate and epoxy compound blocked using caprolactam or phenol, and secondary with RFL adhesive solution. A method of treatment has been proposed and used.

U.S. Patent Nos. 3,730,892, 4,054,634 and 4,108,781 synthesized organic functionalized silanes with epoxy groups and treated them with 0.2 to 1.5 parts by weight relative to polyester fibers, followed by secondary with conventional RFL adhesive. Although a method of manufacturing a polyester tire cord with improved adhesion is proposed, this method results in an improvement in initial adhesive strength, but increases the stiffness of the final polyester tire cord due to the excessive use of epoxy silane. This may cause deterioration of workability and fatigue properties, and the excessive use of epoxy silane increases the price of the final product.

U.S. Patent No. 6,686,301 and WO 99/046324 also use a mixture of rubber and polyester fibers by using a mixture of amino-functionalized Silanes and organo-functionalized Silanes. Although a method of improving adhesion is proposed, this method also shows an improvement in initial adhesive strength, but at a high temperature, due to the aminolysis of amino silane, the adhesion and fatigue resistance of polyester tire cord and rubber are significantly decreased. Seems.

An object of the present invention is to impart reactivity to polyethylene naphthalate fibers by secondary treatment of polyethylene naphthalate fibers surface treated with an epoxy silane and an aromatic epoxy resin or a mixture of epoxy silane and methacryl silane and aromatic epoxy resin with RFL adhesive. The present invention provides a method for producing polyethylene naphthalate fiber having excellent initial adhesive strength and heat resistant adhesive strength to rubber and maintaining low rigidity and excellent workability.

According to a preferred embodiment of the present invention, the method for producing polyethylene naphthalate fiber of the present invention is 70 to 80 parts by weight of an emulsifier, 10 to 20 parts by weight of epoxy silane and 0 to methacryl silane relative to 100 parts by weight of the silane-epoxy mixture. Preparing a silane-epoxy mixture comprising 15 parts by weight to 15 parts by weight and an aromatic epoxy resin, and treating the polyethylene naphthalate fiber with the silane-epoxy mixture during the spinning process of polyethylene naphthalate fiber; Twisting and weaving the polyethylene naphthalate fibers produced by the process to produce a twisted fabric, and drying and twisting the twisted fabric to obtain heat treated polyethylene naphthalate tire cords by applying tension and the heat treatment RFL as a secondary treatment liquid for polyethylene naphthalate tire cord And a step, and a step of dry and stabilize the tire cord through the second RFL treatment liquid which passes the chakaek.

According to another suitable embodiment of the present invention, in the method for producing a polyethylene naphthalate tire cord of the present invention, 0.1 to 0.5 weight of the silane-epoxy mixed solution to 100 parts by weight of polyethylene naphthalate fiber during the spinning process of the polyethylene naphthalate fiber. Attached.

According to another suitable embodiment of the present invention, it is composed of polyethylene naphthalate fibers produced by the production method of the present invention, and (1) the initial adhesion with rubber measured by H-Test is 15 kgf or more. 12kgf or more of heat-resistance, (2) Initial adhesion to rubber measured by Cross Peel Test is 15kgf / inch or more, heat-resistance of 12kgf / inch or more, and (3) Stiffness Tester Stiffness less than or equal to 5.0 g / cord, and (4) tire cords having a strong residual strength of 60% or more after the fatigue test measured using a shoe-shine type bending fatigue tester. To provide.

When the polyethylene naphthalate fiber for tire cord is manufactured according to the present invention, the polyethylene naphthalate cord shows a high initial adhesive force by introduction of reactive functional groups, and the rigidity is low by using a mixture of epoxy silane, methacryl silane and aromatic epoxy resin. It exhibits this high property, there is no deterioration in adhesion force due to amine decomposition at high temperatures, and thus has an advantageous effect of excellent properties of high temperature adhesion and excellent properties of fatigue resistance.

The method for producing polyethylene naphthalate fibers of the present invention comprises the steps of dissolving an aromatic epoxy resin in an epoxy silane alone or a mixture of epoxy silane and methacryl silane and an emulsifier to produce a silane-epoxy mixture, and spinning process of polyethylene naphthalate fiber. Treating the silane-epoxy mixed solution in the air, twisting and weaving the polyethylene naphthalate fiber prepared by the above process to produce a twisted fabric, heat treating the fabric while drying and applying tension, and heat-treated polyethylene Passing the naphthalate fibers through the RFL adhesive liquid, which is the secondary treatment liquid, and drying and stabilizing the fibers passed through the secondary treatment liquid.

The present invention treats a silane-epoxy mixed solution containing epoxy silane, methacryl silane, and aromatic epoxy resin as a main component in order to impart reactivity and improve fatigue resistance to polyethylene naphthalate fibers for tire cords. After that, a secondary treatment liquid containing RFL adhesive as a main component is used for adhesion between polyethylene naphthalate fiber and rubber. Herein, the silane-epoxy mixed solution imparts reactivity to the polyethylene naphthalate fiber to impart adhesiveness between the fiber and RFL, and the secondary treatment liquid serves to bond the polyethylenenaphthalate fiber treated with primary rubber to the rubber.

Hereinafter, the steps for preparing the silane-epoxy mixed solution according to the present invention will be described. The silane-epoxy mixture of the present invention contains 70 to 80 parts by weight of an emulsifier, 10 to 20 parts by weight of epoxy silane, 0 to 15 parts by weight of methacryl silane, and 1 aromatic epoxy resin based on 100 parts by weight of the total mixture. It is preferable to include from 7 parts by weight.

When the epoxy silane is lower than 10 parts by weight, it is difficult to express sufficient adhesion to the rubber by giving sufficient reactivity to the polyethylene naphthalate fiber.When the epoxy silane is higher than 20 parts by weight, the workability is reduced due to the high rigidity and the inner skin of the cord Furnace characteristics are lowered and manufacturing costs are also increased. In addition, when the aromatic epoxy resin is less than 1 part by weight, the rigidity may lead to a decrease in workability, there is no effect of improving fatigue resistance, and when the methacryl silane is higher than 15 parts by weight or the aromatic epoxy resin exceeds 7 parts by weight. It has a low reactivity, resulting in a decrease in adhesion. The amount of the silane-epoxy mixture is preferably 0.1 to 0.5 parts by weight relative to the polyethylene naphthalate fiber. If it is less than 0.1 part by weight, the adhesive strength with rubber is inferior, and if it is more than 0.5 part by weight, workability is inferior due to high rigidity.

Referring to the step of treating the silane-epoxy mixture to the polyethylene naphthalate fibers according to the present invention. After the production of the silane-epoxy mixture, the silane-epoxy mixture is treated during the spinning process of the polyethylene naphthalate fibers.

Referring to the step of heat treatment after weaving and weaving polyethylene naphthalate fibers produced by the process according to the present invention are as follows. Raw fabric is manufactured by weaving the produced polyethylene naphthalate yarn in the lower direction in the Z direction by using a direct weaving machine and in the upper direction in two directions in the S direction, and then weaving using a weaving machine. The polyethylene naphthalate dough thus produced is dried in the drying zone during the heat treatment process. The drying temperature is preferably 150 to 180 ° C. and dried for 20 to 150 seconds.

When the polyethylene naphthalate fibers dried according to the present invention to pass through the RFL liquid which is a secondary treatment liquid, and the drying and stabilization will be described as follows. After drying, the polyethylene naphthalate dough passes through the secondary treatment solution mainly composed of RFL adhesive, and the polyethylene naphthalate dough passed through the secondary treatment solution undergoes a drying process and then stabilizes by heat treatment in a stabilization region. Adhesion is imparted to the surface of polyethylene naphthalate fibers.

Epoxy functional groups in the silane-epoxy mixture thus prepared increase the compatibility with RFL through chemical reaction with carboxyl groups or hydroxyl groups on the surface of polyethylene naphthalate fiber, and methacryl silane crosslinks between epoxy functional groups to It regulates the curing of polymer chains due to high reactivity, and the benzene ring in aromatic epoxy prevents chain breakage in the molecule even at high temperatures due to its stable chemical structure. Thus, the silane-epoxy mixture and RFL adhesive The produced polyethylene naphthalate tire cord has high initial adhesive strength with rubber, and at the same time, there is no deterioration of adhesive strength due to amine decomposition at high temperature, so it has excellent adhesive strength and excellent fatigue resistance by introducing aromatic epoxy resin. Have

The silane and aromatic epoxy resin used in the present invention preferably has the following chemical structural formula.

(n = 2 내지 5)Epoxy Silanes:

(n = 2 to 5)

(n = 2 내지 5)Methacryl silane:

(n = 2 to 5)

(n = 2 내지 5)Amino Silanes:

(n = 2 to 5)

(x = 2 내지 8)
-Aromatic epoxy:

(x = 2 to 8)

Hereinafter, the configuration and effects 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) Evaluation method of adhesive force (kgf): H-Test

As a method of showing the adhesive strength between the heat treated cord and the rubber, the cord was placed in a rubber block and vulcanized at a pressure of 50 kgf / cm ² at 160 ° C. for 20 minutes (initial) or 170 ° C. for 60 minutes (heat resistance). Adhesion is measured at a tensile speed of 200 m / min using a slow elongation type tensile tester. The same test was carried out 10 times to obtain an average value. Other methods were performed according to ASTM D4776-98.

(b) Evaluation method of cross peel adhesive force (kgf / inch)

A method of expressing the adhesion between the heat treated cord and the rubber, topping the rubber on the cord, and then making a specimen by crossing two layers of the topping cord, and putting it in a mold 160 ° C, 20 minutes (initial) or 170 ° C, 60 minutes After vulcanization at a pressure of 50 kgf / cm ² (heat resistance), the topping cord was cut into 1 inch, and then the adhesive force peeled off at a tensile speed of 200 m / min was measured using an Instron low speed tensile tester. The same test was carried out 10 times to obtain an average value.

(c) Stiffness Evaluation Method

As a method of indicating the rigid characteristics of the heat treated cord, the stiffness is measured by taking a cord, mounting it on a stiffness tester, and applying a load to measure a load in which the cord is bent. The same test was carried out five times to obtain an average value.

(d) Evaluation method of fatigue resistance

A measure of the resistance value against external stress of the heat treatment cord, which simulates tire running conditions. In the present invention, a shoe-shine type endothelial test was carried out. Topping the rubber on the cord of 30EPI (Ends Per Inch) interval and attaching it in two layers, followed by vulcanization at 160 ° C. for 20 minutes to produce a specimen. , After applying 70kg of load in the Fatigue Tester and applying 100,000 repetitive loads, the cord was collected and the strength was measured at a tensile speed of 300m / min using Instron's low speed extension type tester. Measure the strong survival rate. The strength of the cord was measured by taking 10 strands of cord before and after fatigue, and the fatigue test was performed three times. Code strength measurement was performed according to ASTM D885.

[Examples 1 to 4]

Polyoxyethylene (Polyoxyethylene, POE) is used as an emulsifier, γ-Glycidoxypropyltrimethoxysilan (Dow Corning ^® Z-6040) is used as the epoxy silane, and γ is used as the methacryl silane. - a-methacryloxypropyltrimethoxysilane propyltrimethoxysilane (γ-methacryloxypropyltrimethoxysilane) (Dow Corning ® Z-6030) was used. As an aromatic epoxy resin, EPI-REZ ™ Resin 6006-W-68 manufactured by Hexion of Ortho-Cresylic Novolac type was used. The content was 72.5 parts by weight of POE, 20 parts by weight of epoxy silane, 2.5 parts by weight of methacryl silane and 5 parts by weight of aromatic epoxy resin, based on 100 parts by weight of silane mixture. Yarn was prepared by treating the silane-epoxy mixed solution prepared above during the polyethylene naphthalate fiber (1000d) spinning process. The amount of the silane-epoxy mixed solution attached at this time was 0.30 parts by weight per 100 parts by weight of polyethylene naphthalate yarn. The fabricated polyethylenenaphthalate yarn was lowered in Z direction by direct weaving machine, and the upper edge in S direction was added to 430TPM (Twist Per Meter), respectively, and the resultant was twisted into 2 pieces and weaved by using a weaving machine. Fabric). The polyethylenenaphthalate dough thus prepared was dried at 170 ° C., impregnated in a RFL adhesive solution as a secondary treatment solution, and then dried at 170 ° C. and stabilized at 245 ° C. to prepare polyethylene naphthalate fiber for rubber reinforcement. The composition of the silane mixture solution and the composition of the RFL adhesive solution of the above embodiment are shown in Table 1 and Table 2, and the evaluation results of the obtained polyethylene naphthalate tire cord are shown in Table 3.

Comparative Example 1 to Comparative Example 4

The silane-epoxy mixture was prepared using 10 parts by weight of methacryl silane and 15 parts by weight of amino silane. In this case, the amino silane was N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane (N- (β-aminoethyl) -γ-aminopropyltrimethoxysilan) (Dow Corning ^® Z-6020), and an aromatic epoxy resin was used. 5 parts by weight was used. The composition of the silane mixture used in the comparative examples is shown in Table 1 below, and was treated with the RFL adhesive solution of the same composition as in Example. The evaluation results at this time are shown in Table 3.

division
Content (parts by weight) Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Silane-Epoxy Mixture
Per 100 parts by weight Emulsifier 72.5 70 80 72.5 70 70 70 60 Epoxy silane 20 10 15 15 - 25 15 10 Methacryl silane 2.5 15 - 10 10 5 - 20 Amino silane - - - - 15 - 10 - Aromatic
Epoxy resin 5 5 5 2.5 5 - 5 10 Silane-Epoxy Mixture Amount
(Per fiber part) 0.30 0.27 0.18 0.34 0.24 0.43 0.33 0.15

additive density(%) Parts by weight (wt%) Resorcinol 29% 7.2 Formaline 37% 3.2 Vinylpyridine latex
(Vinylpyridine Latex) 41% 48.0 NaOH 10% 0.6 H ₂ O - 41.0

division
Physical property results Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 H-Test
(kgf) Early 17.3 16.5 17.6 17.6 14.8 18.3 15.1 13.4 Heat resistant 14.7 13.4 14.5 13.8 10.0 14.0 12.3 11.4 Cross
Peel
(kgf / inch) Early 16.3 16.5 17.2 18.0 15.0 21.1 15.7 13.8 Heat resistant 14.7 12.9 14.9 15.0 9.3 15.5 11.8 9.5 Stiffness (g / cord) 3.9 3.6 4.5 5.0 4.0 9.0 6.2 4.1 After fatigue test
Strong Survival Rate (%) 75 66 70 63 49 51 55 61

Although the present invention has been described in detail with reference to the embodiments, those skilled in the art will be able to make various modifications and modifications to the embodiments without departing from the spirit of the invention. The invention is not limited by these variations and modifications.

Claims (3)

Preparing a silane-epoxy mixture comprising 70 to 80 parts by weight of an emulsifier, 10 to 20 parts by weight of epoxy silane, 0 to 15 parts by weight of methacryl silane, and 1 to 7 parts by weight of an aromatic epoxy resin, based on 100 parts by weight of the silane-epoxy mixture;
Treating the silane-epoxy mixture with the polyethylene naphthalate fiber during the spinning process of the polyethylene naphthalate fiber;
Twisting and weaving polyethylene naphthalate fibers produced by the process to produce dough;
Drying the dough and applying tension to obtain a heat-treated polyethylene naphthalate cord;
Passing the heat treated polyethylene naphthalate cord through a RFL adhesive solution, which is a secondary treatment solution; And
Drying and stabilizing the cord passing through the secondary RFL treatment solution; Method of manufacturing a polyethylene naphthalate tire cord comprising a. The method of claim 1,
The method of producing a polyethylene naphthalate tire cord, characterized in that the silane-epoxy mixture is attached 0.1 to 0.5 parts by weight based on 100 parts by weight of polyethylene naphthalate fiber during the spinning process of the polyethylene naphthalate fiber. The polyethylene naphthalate tire cord manufactured by the manufacturing method of Claim 1 or 2, and having the following physical properties.
(1) The initial adhesive strength with rubber measured by H-Test is 15kgf or more and the heat resistant adhesive strength is 12kgf or more. (2) The initial adhesive strength with rubber measured by Cross Peel Test is 15kgf / more than 12 inches of heat resistance and more than 12kgf / inch (3) Stiffness measured using Stiffness Tester 5.0g / cord or less (4) Using Shoe-shine type bending fatigue tester The strength of the cord remains above 60% after the measured fatigue test.