KR20120073961A - Producing method of aramid filament for rubber reinforcement - Google Patents

Abstract

PURPOSE: A method for fabricating an aramide fiber for rubber reinforcement is provided to enhance adhesion between the rubber and aramide fibers. CONSTITUTION: A method for fabricating an aramide fiber comprises: a step of mixing epoxy, blocked diisocyanate, VP latex, and PFL adhesive to prepare a primary treatment solution; a step of applying tension to the aramide fiber and passing the aramide fiber through the primary treatment solution; a step of drying the fiber and applying the tension to the dried fiber; a step of passing the aramide fiber through the RFL solution; and a step of drying and stabilizing the fiber.

Description

Producing Method of Aramid Filament for Rubber Reinforcement

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive composition of aramid fibers for rubber reinforcement, which improves adhesion between rubber and heat treated tire cords, and also improves coverage with rubber when exposed to rubber at high temperatures. Is about

Aramid fibers represented by polyamides are used as rubber reinforcing fibers for tires, hoses, belts and the like because they exhibit excellent physical properties such as high strength and high modulus. It is particularly popular for carcass and cap ply of ultra high performance tires and is widely used due to its excellent form stability due to high modulus. It is currently used in tires of racing cars. However, due to high price and lack of adhesion, the scope of use is limited. The cause of the decrease in adhesive strength is that the surface of the aramid fibers is relatively inert, so that the adhesive strength with the rubber is insufficient, and the physical properties of the aramid fibers cannot be exhibited in full. Generally, aramid fibers are subjected to dipping in much the same way as PET fibers. In addition, aramid fiber is initially inferior to PET, heat-resistant adhesion.

Looking at the composition for aramid heat treatment that is commonly used in general, a chemical treatment method for treating the surface of the aramid fibers with a drug is mainly used. For example, a so-called two-bath treatment method has been proposed in which treatment with a highly reactive chemical agent such as an aliphatic epoxy compound and an isocyanate compound blocked to impart adhesion, followed by treatment with conventional RFL. However, the aramid tire cords thus treated do not exhibit sufficient initial adhesion unlike PET tire cords. The reason for this is that the concentration of the dip solution is low, and therefore, Dip Pick Up (DPU) is low, so that the thickness of the urethane film on the aramid surface is low and the modulus of the film is low, thereby preventing sufficient adhesion. In addition, if the dip liquid is raised by increasing the concentration of the dip liquid, sufficient initial adhesive strength can be obtained, but in this case, the frequency of gum up is high and the cleaning mouth is shortened, resulting in a decrease in productivity. .

The present invention has been made in order to solve the above problems, excellent initial and heat-resistant adhesive strength to the rubber and no toxic substances or impurities generated in the treatment process, the surface treatment method of aramid fibers for rubber reinforcement can be improved productivity And to provide a primary adhesive composition used in the treatment method.

The present invention for achieving the above object, the step of preparing a primary treatment liquid by mixing pure, epoxy, blocked diisocyanate, VP latex, and RFL adhesive; Passing through the primary treatment liquid while applying tensile force to aramid fibers; Drying the fibers passing through the first treatment liquid; Heat treating the dried fibers while applying tension; Passing the heat treated aramid fibers through an RFL solution that is a secondary treatment solution; And drying and stabilizing the fibers passing through the secondary treatment liquid.

It is preferable that this invention also contains 0.5-1.5 weight part of aromatic epoxy or mixed epoxy with aliphatic with respect to 100 weight part of pure waters.

In addition, the primary treatment liquid preferably comprises 2.0 to 3.0 parts by weight of blocked diisocyanate.

In addition, it is preferable to contain 0.1 to 0.4 part by weight of the VP latex.

In addition, in order to emulsify the epoxy, an appropriate emulsifier is selected, and the dosage is preferably 0.05 to 1.0 parts by weight.

The present invention also provides an aramid fiber for rubber reinforcement having an initial adhesive strength of 10 kgf or more and a high temperature adhesive force of 9 kgf or more by being processed by the above method.

As described above, the adhesive solution according to the present invention is excellent in stability, and the aramid cord made of the adhesive solution exhibits high initial adhesive force, and excellent adhesion at high temperature by using an aromatic epoxy, and at the same time coverage when exposing rubber at high temperature. Coverage shows excellent properties.

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

In order to provide adhesiveness to aramid fibers for rubber reinforcement, the present invention uses a primary treatment liquid containing aromatic epoxy and diisocyanate as a main component and a secondary treatment liquid containing RFL adhesive as a main component. Here, the primary treatment liquid imparts adhesion between aramid and RFL, and the secondary treatment liquid serves to bond the primary treated aramid fibers with rubber.

The primary treatment liquid of the present invention will be described as follows.

It is preferable that the primary process liquid of this invention contains 0.5-1.5 weight part of aromatic epoxy or mixed type epoxy with aliphatic with respect to 100 weight part of pure waters. When the amount of epoxy is less than 0.5 parts by weight, it is difficult to express sufficient adhesive force, and when the amount of epoxy is higher than 1.5 parts by weight, the workability is lowered due to the high rigidity and the fatigue resistance of the cord is reduced. In addition, it is preferable to include 2.0 to 3.0 parts by weight of blocked diisocyanate. When the content of diisocyanate is 2.0 parts by weight or less or 3.0 parts by weight or more, it is difficult to develop sufficient adhesive force. In addition, it is preferable to contain 0.1 to 0.4 part by weight of the VP latex. In addition, in order to emulsify the epoxy, an appropriate emulsifier is selected, and the dosage is preferably 0.05 to 1.0 parts by weight. If the amount is 0.05 parts by weight or less, the emulsifying power is not sufficient, resulting in poor emulsification stability, and in the case of 1.0 parts by weight or more, it adversely affects the adhesion. The total solid concentration of the primary treatment liquid is preferably 1.5 to 7 parts by weight, more preferably 2.0 to 5.0 parts by weight.

After the preparation of the primary treatment liquid, the aramid fibers are generally passed through the immersion method while applying tension. The tension of the fibers is suitably 0.05 to 0.20 g / d, and the passed aramid fibers are dried in the drying zone. At this time, the drying temperature is preferably 140 to 170 ° C, and the treatment is performed for 20 to 150 seconds. The dried fibers are heat treated at 200 to 280 ° C. for 20 to 150 seconds. When the heat treatment temperature is less than 200 ℃ dimensional stability of the cord is lowered due to the lack of thermal history, if it exceeds 280 ℃ may cause thermal decomposition of the treatment liquid.

The aramid fibers after the heat treatment is passed through the secondary treatment solution mainly composed of RFL adhesive, and the aramid fibers passed through the secondary treatment solution is subjected to the drying process and stabilized by heat treatment in the stabilization zone again. The adhesive force is given to.

The adhesive liquid thus prepared has excellent stability, and the aramid cord made of the adhesive liquid exhibits high initial adhesive strength with rubber, and has excellent adhesive force retention at high temperature, and at the same time, excellent rubber adhesion rate, that is, coverage. Indicates.

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 examples and examples, the following evaluation methods were utilized.

(a) Adhesion (kgf)

As a method of showing the adhesion between the treatment cord and rubber, the cord was placed in a rubber block and vulcanized at 50 kgf / cm ² at 150 ° C. for 30 minutes (initial) or 170 ° C. for 90 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) Rubber Adhesion, Coverage

As a measure of the adhesion of rubber to the cord, the cord peeled from the rubber was observed, and the rubber adhered to the cord surface was classified into 5 grades up to AE. Grade A refers to the case where more than 80% of the rubber is attached or rubber erection occurs.The grade B is 60 to 80%, the grade C is 40 to 60%, the grade D is 20 to 40%, and the grade E is 20% or less. It is a state of being.

EXAMPLE 1-5

The aromatic epoxy compound was used 0.7 wt% with respect to 100 wt% of pure water, and the aqueous caprolactam block diphenylmethane diisocyanate dispersion (trade name Grilbond IL-6, EMSKEMIE Co., solid concentration 50%) was gradually mixed. In addition, 0.2 wt% of VP latex (15:15:70 weight ratio of vinylpyridine, styrene and butadiene) was added. In addition, 0.1 wt% of an emulsifier for emulsifying epoxy was added to prepare a primary treatment solution. Aramid fibers (1500den / 2ply) was immersed in the prepared primary treatment solution and passed through, dried for 2 minutes at 150 ℃ in the drying zone and heat-treated at 240 ℃. The aramid fibers subjected to the heat treatment were again impregnated with the RFL adhesive solution, which is a secondary treatment solution, dried at 150 ° C., and stabilized at 245 ° C. to produce aramid fibers for rubber reinforcement.

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

division
Content (wt%)
(Per 100 wt% pure) Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Comparative Example 3 Aromatic epoxy 0.7 1.0 1.3 1.0 0.5 - - - Aliphatic epoxy - - - 0.5 1.0 0.7 1.0 1.3 Blocked Diisocyanate 2.0 2.5 2.5 2.0 2.0 2.5 2.0 2.5 VP Latex 0.2 0.2 0.3 0.2 0.2 0.3 0.2 0.2 Emulsifier 0.1 0.3 0.3 0.3 0.3 0.1 0.3 0.3

division
Physical property results Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Comparative Example 3 Adhesion
(kgf) Early 10.4 11.8 11.3 12.7 11.3 8.3 12.5 9.3 Heat resistant 7.2 8.2 7.8 9.8 8.0 5.7 6.3 6.9 Coverage C B C B C E D D

[Comparative Example 1? 3]

Only the aliphatic epoxy was used without adding the aromatic epoxy, and the primary treatment liquid of the same composition as in Example was prepared. The conditions and evaluation results at this time are shown in Tables 1 and 2.

Claims (4)

Preparing a primary treatment liquid by mixing pure epoxy, aromatic alone or aliphatic mixed type epoxy, blocked diisocyanate, VP latex, and RFL adhesive;
Passing through the primary treatment liquid while applying tensile force to aramid fibers;
Drying the fibers passing through the first treatment liquid;
Heat treating the dried fibers while applying tension;
Passing the heat treated aramid fibers through an RFL solution that is a secondary treatment solution;
Method for producing aramid fibers comprising the step of drying and stabilizing the fibers passed through the secondary treatment liquid. The method according to claim 1,
The method of producing aramid fibers, characterized in that the mixed epoxy with the aromatic alone or aliphatic in the primary treatment liquid occupies 0.5 to 1.5 parts by weight based on 100 parts by weight of pure water. The method according to claim 1,
The blocked diisocyanate in the primary treatment liquid occupies 2.0 to 3.0 parts by weight based on 100 parts by weight of pure water, and the VP latex comprises 0.1 to 0.4 parts by weight based on 100 parts by weight of pure water. Method of preparation. The method according to any one of claims 1 to 3,
A method of producing aramid fibers for rubber reinforcement having an initial adhesive strength of 12kgf or more and a heat resistant adhesive force of 10kgf or more by passing through the prepared primary and secondary treatment solutions.