KR20110120751A - Preparation method of tire cord and tire - Google Patents

Abstract

PURPOSE: A method for manufacturing a tire cord is provided to simplify process by simple plasma process and to ensure excellent adhesion with a tire. CONSTITUTION: A method for manufacturing a tire cord comprises: a step of forming a grey yarn for the tire cord containing a plurality of monofilament fiber; and a step of doubling and twisting the grey yarn at more than (550-0.1642*yarn fineness) TPM and less than (720-0.1642*yarn fineness) TPM. The grey yarn contains polyester polymers, polyamide polymers, regenerated cellulose, polyolefin ketone polymers, or polyvinyl alcohol polymers. The surface of the grey yarn is treated by plasma for 5-300 seconds.

Description

Manufacturing method and tire of tire cord {PREPARATION METHOD OF TIRE CORD AND TIRE}

The present invention relates to a tire cord manufacturing method and a tire. More specifically, the present invention is a simple and environmentally friendly treatment process, a method for producing a tire cord that can provide a tire cord exhibiting improved adhesion to the tire and to a tire comprising the tire produced therefrom. It is about.

In the past, tire cords made of polymer fibers such as polyester (polyethylene terephthalate and the like), polyamide (nylon and the like), cellulose (rayon and the like) or polyvinyl alcohol have been widely used as reinforcing materials.

However, the polymer fibers constituting the tire cord generally have a disadvantage in that adhesiveness with the rubber constituting the tire is not good. For this reason, the method of pasting the tire cord and the tire which consists of the said polymer fiber using the resorcinol-formaldehyde-rubber latex (RFL) resin (adhesive agent) has been applied widely.

However, since the surface of the polymer fiber is generally hydrophobic, the RFL resin sufficiently penetrates and hardly exhibits excellent adhesion. For this reason, it was not easy to obtain sufficient adhesive force of the tire cord and the tire only by the RFL resin.

For this reason, in the past, a method of primarily treating a surface of a tire cord using parachlorophenol-based RF resin (PEXUL) or an epoxy compound, etc., and then again applying a second treatment with RFL resin or the like has been applied.

However, in the method of using the parachlorophenol-based RF resin (PEXUL), since ammonia water, which is a harmful substance, is used in a large amount as a main solvent thereof, a separate purification facility is required, which may cause environmental pollution and the like. There was this.

In addition, even in the method using the epoxy compound, environmental contamination by such an epoxy compound may occur, and the adhesive layer (that is, the surface treatment layer using the epoxy compound or the like) on the tire cord is too hard, resulting in stiffness of the tire cord. There are problems such as high and low flexibility.

In addition, in the above-described prior art, since the tire cord has to be subjected to a two-step surface treatment process using a separate compound, the manufacturing process of the tire cord is relatively complicated, and the drying and heat treatment processes have to be performed twice, thus producing a facility. There are also disadvantages such as greater energy consumption doubled.

Accordingly, the present invention is to provide a method for producing a tire cord that allows the provision of a tire cord showing excellent adhesion to the tire even with a simpler and more environmentally friendly treatment process.

The present invention also provides a tire comprising the tire cord obtained by the above production method.

Accordingly, the present invention comprises the steps of forming a yarn for tire cords each comprising a plurality of monofilament fibers having a fineness of 2.0 ~ 3.5 denier (d); Coalescing the tire cord yarn; Treating the surface of the twisted yarn with a plasma of oxygen, air, helium or argon; And it provides a method of producing a tire cord comprising the step of treating the plasma-treated twisted yarn with a resorcinol-formaldehyde-rubber latex (RFL) adhesive.

The present invention also provides a tire comprising a tire cord produced by the above method.

Hereinafter, a method of manufacturing a tire cord according to a specific embodiment of the present invention, a tire using the same, and a method of manufacturing the same will be described.

According to one embodiment of the invention, forming a yarn for a tire cord comprising a plurality of monofilament fibers each having a fineness of 2.0 to 3.5 denier (d); Coalescing the tire cord yarn; Treating the surface of the twisted yarn with a plasma of oxygen, air, helium or argon; And treating the plasma treated plywood with a lesosinol-formaldehyde-rubber latex (RFL) adhesive.

As a result of the experiments of the present inventors, in the process of producing a tire cord from the monofilament fibers, if the surface of the polymer fiber for the production of the tire cord, that is, the surface of the tire cord yarn or its conjugate twisted yarn with a predetermined plasma, It has been confirmed that the surface of the yarn or twisted yarn may be oxidized or modified by oxygen radicals or the like to become hydrophilic.

In addition, as the tire cords are manufactured from monofilament fibers having a relatively thin range of fineness, the surface area of the yarns or twisted yarns including the monofilament fibers can be expanded without making the tire cord manufacturing process difficult. It is possible to increase the fiber area. This may allow the RFL adhesive (resin) to better penetrate the twisted yarn surface.

Therefore, according to one embodiment of the present invention, after the plasma surface treatment and hydrophilic modification, if the plywood yarn having a large surface area or the like is treated with the RFL adhesive, the tire cord may be manufactured in such a form that the RFL adhesive is sufficiently penetrated. . Thus, such tire cords can exhibit better adhesion with the tires.

In particular, according to the method described above, surface treatment with a plasma and then treatment with an RFL adhesive resulted in a tire cord that is superior to the tire, to a degree that is comparable to, or even better than, two treatments with an epoxy compound and an RFL adhesive. It was confirmed to exhibit adhesive force.

Therefore, according to the manufacturing method according to the embodiment of the present invention, it is possible to provide a tire cord that exhibits excellent adhesion to the tire even with a simple plasma treatment step, without the use of contamination-causing substances such as epoxy compounds.

On the other hand, in the tire cord manufacturing method according to the embodiment of the invention, in the step of combining, the tire cord yarn (550-0.1642 * yarn fineness) TPM or more (720-0.1642 * yarn fineness) meets the TPM or less It can be combined in the training, more specifically, (550-0.1642 * yarn fineness) TPM (combination of the yarn fineness) or more than (670-0.1642 * yarn fineness) can be combined with the two strands of the lower twist yarns that are less than the TPM to S stations of the same training. . By proceeding the joining step with this training and method, it is possible to increase the surface area of the twisted yarn and to better penetrate the RFL adhesive. As a result, it becomes possible to provide a tire cord that exhibits better adhesion to the tire.

In addition, in the tire cord manufacturing method, the tire cord yarn may include 250 to 1000 monofilament fibers, the total fineness may be 1000 to 2000 denier (d). Accordingly, it can be suitably used as a tire cord for reinforcing tires.

In the plasma treatment step, the surface of the braided twisted yarn may be treated with a plasma power of 100 to 500W, and preferably, with a plasma power of 240 to 360W. If the power of the plasma treatment process is too low, the surface modification effect according to the plasma treatment process may hardly appear, and thus the adhesive force between the tire cord and the tire treated with the RFL adhesive may not be sufficient. On the contrary, when the plasma power is excessively high, there is almost no additional surface modification effect or adhesion improvement effect. On the contrary, the energy of plasma applied to the surface of the twisted yarn or the like is too high, damaging the surface tissue such as the polymer fibers forming the tire cord. You can. For this reason, the adhesive force between a tire cord and a tire, or the reinforcement degree of a tire by a tire cord may rather fall.

In addition, in the tire cord manufacturing method, the surface of the ply-twisted yarn can be plasma-treated for 5 to 300 seconds, preferably plasma treatment for 100 to 200 seconds. If the plasma treatment time is too short, the surface modification effect or the adhesion improving effect between the tire cord and the tire due to the plasma treatment may not be sufficient. On the contrary, when the plasma treatment time is excessively long, there is almost no additional surface modification effect or adhesion improvement effect, and the energy of plasma applied to the surface of the twisted yarn or the like may be increased to damage the surface tissue. For this reason, the adhesive force between a tire cord and a tire, or the reinforcement degree of a tire by a tire cord may rather fall.

In the tire cord manufacturing method, plasma of oxygen, air, helium or argon applied to the surface treatment of the tire cord may be an atmospheric pressure plasma of these gases. Such plasma is a state in which the gas particles constituting the ion are ionized and maintain the overall electrical neutrality, and the ionization degree is relatively low (for example, about 10 ⁻⁵ ) and the average temperature becomes a low temperature plasma close to room temperature. Typically, such low temperature plasma treatment process is carried out in a reactor of low pressure close to vacuum, but the experimental results of the present inventors, it was found that even if the application of the atmospheric pressure plasma can achieve the intended adhesion improvement effect of the present invention. Thereby, it can contribute more to the mass productivity and practicality of the manufacturing process of a tire cord.

On the other hand, the material or type of the tire cord to which the manufacturing method according to the embodiment of the present invention is applicable is not particularly limited, and may be applied for the manufacture of any tire cord that has been applied for reinforcement of the tire.

For example, the method for producing the tire cord is polyester polymer such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), polyamide polymer such as nylon or p-aramid, viscose rayon or lyocell It can be applied to tire cords comprising various polymeric fibers such as regenerated cellulose polymers, polyolefin ketones (POKs) or polyvinyl alcohols.

In addition, the type of tire cord is not particularly limited, and may be suitably applied to the manufacture of tire cords for body plies or cap plies that have been applied for reinforcement of tires.

The manufacturing method is applied for the production of tire cords of various materials or types described above, it is possible to adhere the tire cord to the tire with excellent adhesion, thereby obtaining a desirable reinforcement effect of the tire using the tire cord. . However, the tire cord manufacturing method may be suitably applied to a tire cord including a polyester-based polymer fiber such as polyethylene terephthalate, from which a tire capable of desirable reinforcement of the tire while having excellent adhesion to the tire A code may be provided.

On the other hand, except for the matters described above, the process of forming the yarn for the tire cord from a plurality of monofilament, and combining them to form a twisted yarn may be in accordance with the conventional tire cord manufacturing process. For example, a predetermined polymer may be melt-spun to form monofilament fibers having a predetermined fineness, and the unstretched yarn including a plurality of such monofilament fibers may be stretched, heat set, and wound to obtain the yarn for tire cord. In addition, it is possible to form the combined yarn by combining the tire cord yarn for a certain number of years. However, since the melt spinning, stretching, heat setting, and winding process according to a conventional tire cord manufacturing process, further description thereof will be omitted.

In addition, in the tire cord manufacturing method, the surface of the twisted yarn is treated with plasma under the above-described conditions to be hydrophilic, and then the twisted yarn is treated with a resorcinol-formaldehyde-rubber latex (RFL) adhesive. do. As a result, a tire cord can be produced in which the RFL adhesive effectively penetrates the surface of a hydrophilic-modified jointed yarn having a large surface area and exhibiting excellent adhesion to a tire.

In this case, the RFL adhesive treatment step may be performed within 6 hours, preferably 2 hours after the plasma treatment step described above, it is more preferable to proceed to the plasma treatment step and RFL adhesive treatment step in a continuous process. When too long time passes after the plasma treatment step, the surface of the surface modification effect by the plasma treatment is poor, it may not be properly manufactured tire cord showing excellent adhesion.

In addition, in the treatment process of such an adhesive, the RFL adhesive can be used without any particular limitation that has been generally used in the manufacture of various tire cords. That is, the RFL adhesive may be dissolved in a solvent RFL resin obtained by the reaction of resorcinol, formaldehyde and rubber latex according to a conventional configuration, wherein the rubber latex, for example, vinyl Pyridine-based latexes can be used.

The RFL resin may be obtained by reacting 5 to 35% by weight of resorcinol, 2 to 10% by weight of formaldehyde and 60 to 90% by weight of rubber latex, for example, vinylpyridine-based latex. . In addition, the RFL resin may be dissolved in an aqueous solvent or an organic solvent, for example, water, methyl isobutyl ketone, xylene, ethyl benzene or methyl ethyl ketone or two or more mixed solvents selected from them to obtain an RFL adhesive. The concentration of the RFL resin may be 15 to 30% by weight.

On the other hand, in the tire cord manufacturing method, such an RFL adhesive may be treated to the twisted yarn according to conventional process conditions and methods. For example, the adhesive twisted yarn may be treated with a dip solution containing an RFL adhesive or the like, followed by drying and heat treatment. In this case, progress conditions such as a drying or heat treatment process also follow general conditions.

The tire cord manufactured through the plasma treatment and the RFL adhesive treatment process can be obtained in a state where the RFL adhesive penetrates well into the hydrophilic modified surface having a large surface area, and the RFL adhesive shows excellent adhesion with the tire. Can be. Therefore, a tire cord exhibiting excellent adhesion to the tire can be obtained through the above-described manufacturing method, and the tire can be effectively reinforced using the tire cord.

In particular, in the manufacturing process of the tire cord described above, since the excellent adhesion between the tire cord and the tire can be obtained without using a separate pollutant such as an epoxy compound, it is possible to simplify the manufacturing process of the tire cord, The process can be secured. In addition, as the tire cord is treated only with the RFL adhesive without treatment with the epoxy compound, disadvantages such as excessively hardened adhesive layer on the tire cord, increased stiffness of the tire cord, and reduced flexibility can be greatly reduced.

On the other hand, according to another embodiment of the invention, there is provided a tire comprising a tire cord manufactured by the above-described method. Such tires may be pneumatic tires to which the tire cords are bonded.

At this time, the method or condition of the tire cord adhesion to the tire may be obvious to those skilled in the art in consideration of the specific type, material or shape of the tire or the type, material or shape of the tire cord adhered thereto.

Such a tire may exhibit excellent adhesion with a tire cord, and for example, when a tensile test is performed under conditions of 100 mm / min at room temperature and a load of 25 kgf, the maximum stress between the tire and the tire cord is 7.8 to 10.6 MPa, More specifically, it can exhibit excellent adhesive strength ranging from 8.3 to 10.6 MPa. Thus, the tire may be preferably reinforced by the tire cord to exhibit excellent physical and mechanical properties.

As described above, according to the present invention, there is provided a method for producing a tire cord, which makes it possible to produce a tire cord exhibiting excellent adhesion with a tire, even with a simple plasma treatment step, without the use of contamination-causing substances such as epoxy compounds.

Therefore, it is possible to provide a tire cord that can be adhered to the tire with excellent adhesion while the tire cord manufacturing method can be more simplified and environmentally friendly. Such tire cord can be used to reinforce the tire preferably.

Figure 1 is a graph showing the results of measuring the hydrophilic change of the surface of the PET composite twisted yarn after air plasma treatment of the surface of the PET twisted yarn while varying the treatment time in the test example.
Figure 2 is a graph showing the result of measuring the hydrophilic change of the surface of PET ply twisted yarn after oxygen plasma treatment of the surface of PET plywood while changing the treatment time in the test example.

Hereinafter, the configuration and effects of the invention will be described in more detail with reference to specific examples and comparative examples in order to help understanding of the invention. However, the following examples are only intended to more clearly understand the invention, and the invention is not limited to the following examples.

Test Example 1 Evaluation of Surface Hydrophilic Modification (PET Fiber)

The polyethylene terephthalate (PET) polymer was melt-extruded at a spinning speed of 3000 m / min, stretched, heat-set and wound at a draw ratio of 1.8 to prepare a PET yarn having a total fineness of 1500 denier and filament number 440. PET monofilament fibers contained in these yarns had a fineness of 3.4 denier.

These yarns were twisted and twisted with two strands of Z-bonded yarns of 420TPM with S-leads of the same twist number to be used as samples.

This twisted yarn was cut into a size of 40 cm and the surface was treated with atmospheric plasma of oxygen or air.

First, using the atmospheric pressure plasma, the surface of the twisted yarn was treated with a plasma power of 350W while varying the plasma treatment time to 10 seconds, 20 seconds, 30 seconds, 60 seconds, 90 seconds and 120 seconds. One end of the PET twisted yarn was immersed in 100 ppm methylene blue aqueous solution for 1 minute, and the height of the methylene blue aqueous solution ride was measured. The measured height is shown in FIG. .

In addition, using the atmospheric pressure plasma of oxygen, the surface of the twisted yarn was treated with a plasma power of 350 W while varying the plasma treatment time at 120 seconds and 300 seconds. One end of the PET twisted yarn was immersed in 100ppm methylene blue aqueous solution for 1 minute, and the height of the methylene blue aqueous solution ride was measured. The measured height is shown in FIG. .

Referring to FIGS. 1 and 2, when the surface of the PET twisted yarn is treated with plasma of oxygen or air, the height of the methylene blue aqueous solution is increased and the color of the surface of the PET twisted yarn dyed with methylene blue is relatively dark. It became. This is because, as the surface of the PET twisted yarn is modified to be hydrophilic by plasma treatment, the aqueous methylene blue solution penetrates more into the PET twisted yarn, and as a result, the height of the methylene blue aqueous solution ride up is relatively low. That is, the experimental results confirmed that the surface of the PET twisted yarn was modified to be hydrophilic by plasma treatment.

In addition, through the experimental results described above, the surface of the PET plywood can be modified hydrophilically by plasma treatment, so that the aqueous solution, and furthermore, the RFL adhesive can effectively penetrate, and thus, the PET plywood is converted into the RFL adhesive. In the case of processing, it is confirmed that a tire cord can be produced that exhibits good adhesion with the tire.

Test Example 2 Evaluation of Adhesion to Rubber

Rubber samples for adhesion evaluation were prepared as follows. First, each component was blended and molded at a blending ratio shown in Table 1 to prepare a rubber sample. At this time, the size of the rubber sample was 75 X 75 X 12mm, the weight was about 9.8g.

In Table 1, Tufdene 3335 (Asahi Co., Ltd.) was used as the S-SBR rubber, CBS refers to N-cyclohexyl-2-benzothiazolesulfenamide, and DPG refers to diphenylguanidine. do.

On the other hand, polyethylene terephthalate tire cord for the evaluation of adhesion to the rubber sample was prepared. The polyethylene terephthalate tire cord was produced by producing a polyethylene terephthalate plywood yarn by the method described in Test Example 1, followed by plasma treatment, adhesive coating, and the like by the method described below. However, in the case of Comparative Example 1 was treated with an epoxy compound (EMS G-1701) without the plasma treatment, and then treated with RFL adhesive in the same manner as in the following Examples to prepare a tire cord. In the case of Comparative Example 2, a yarn having a filament number of 250 and a total fineness of 1,500 deniers was produced using PET monofilament fibers having a fineness of 6.0 denier, and a twisted yarn was prepared therefrom. ,

While varying plasma treatment conditions, the surface of the PET twisted yarn was treated with an atmospheric plasma of oxygen or air. At this time, the treatment conditions of the plasma are as summarized in Table 2 below. Subsequently, RFL adhesive was applied to the PET twisted yarn. At this time, RFL adhesive was obtained by dissolving 10% by weight of a condensate of Resorcinol and Formaldehyde in a concentration of 50% in an alkali state, using Latex 57% by weight, 33% by weight of water and Formaldehyde in a concentration of 40%, and the adhesive was added to the PET sum. The final PET tire cord was prepared by applying an amount corresponding to 4% by weight of the twisted yarn, drying at 130 ° C. for 1 minute, and curing at 220 ° C. for 1 minute.

After the PET tire cord was adhered to the rubber sample prepared as shown in Table 1 above, a tensile test was conducted under a condition of 100 mm / min at room temperature and a load of 25 kgf using a tensile tester. At this time, a 38mm grip was used, and a model Instron 3360 (Instron, USA) was used as a universal testing machine as a tensile tester.

As a result of the tensile test, the maximum stress when the PET tire cord and the rubber sample fell was measured, and these measurement results are summarized in Table 2 below.

Tire cord processing conditions Max stress (MPa) Example 1 Plasma Treatment (Air, 350 W, 180 sec) + RFL Adhesive 10.59 Example 2 Plasma Treatment (Air, 350 W, 240 sec) + RFL Adhesive 10.59 Example 3 Plasma Treatment (Air, 500 W, 120 sec) + RFL Adhesive 9.95 Example 4 Plasma Treatment (Air, 500 W, 180 sec) + RFL Adhesive 8.99 Example 5 Plasma Treatment (Oxygen, 350 W, 180 sec) + RFL Adhesive 10.11 Example 6 Plasma Treatment (Oxygen, 350 W, 240 sec) + RFL Adhesive 8.35 Example 7 Plasma Treatment (Oxygen, 500 W, 120 sec) + RFL Adhesive 9.31 Example 8 Plasma Treatment (Oxygen, 500 W, 180 sec) + RFL Adhesive 8.99 Comparative Example 1 Epoxy Compound + RFL Adhesive 8.99 Comparative Example 2 High Fine Monofilament Fiber, Plasma Treated (Air, 350W, 180 sec) + RFL Adhesive 7.46

Referring to Table 2, it was confirmed that the PET tire cord treated with the RFL adhesive after the surface treatment with plasma shows excellent adhesion to the rubber sample. In particular, it was found that even when compared with Comparative Example 1 treated with an epoxy compound and an RFL adhesive according to the previous process, it showed similar or rather similar adhesion.

It was also confirmed that the tire cords of the examples obtained from the lower fineness monofilament fibers exhibited superior adhesion to rubber samples compared to the tire cords of Comparative Example 2 obtained from the high fineness monofilament fibers. This is because the modified fiber area by the plasma can be increased with the use of lower fineness monofilament fibers and the RFL adhesive has better penetrated the plywood surface.

Therefore, according to the above embodiment, it was confirmed that the adhesion between the tire cord and the tire can be easily and eco-friendly without using an epoxy compound.

On the other hand, in contrast to Examples 1 and 4, and also Examples 5, 6 and 8, it was confirmed that the adhesive force is lowered when the plasma power is higher than 360W or the treatment time is longer than 200 seconds. This is due to damage to the surface structure of the PET PET twisted yarn as too much plasma energy is applied to the PET twisted yarn. In addition, the decrease in adhesion is slightly larger in the oxygen plasma than in the air plasma, because the oxygen content in the air plasma is relatively low.

Claims (11)

Forming a yarn for tire cords each comprising a plurality of monofilament fibers having a fineness of 2.0 to 3.5 deniers (d);
Coalescing the tire cord yarn;
Treating the surface of the twisted yarn with a plasma of oxygen, air, helium or argon; And
The method of manufacturing a tire cord comprising the step of treating the plasma-treated twisted yarn with a resorcinol-formaldehyde-rubber latex (RFL) adhesive.
The method of manufacturing a tire cord according to claim 1, wherein in the step of joining, the yarn for tire cord is coalesced with a soft water of not less than (550-0.1642 * yarn fineness) TPM (720-0.1642 * yarn fineness) TPM or less.
The method for producing a tire cord according to claim 1, wherein the yarn for tire cord has a total fineness of 1000 to 2000 denier (d).
The method of producing a tire cord according to claim 1, wherein the surface of the braided twisted yarn is treated with a plasma power of 100 to 500W.
The method of manufacturing a tire cord according to claim 1, wherein the surface of the braided twisted yarn is treated with plasma for 5 to 300 seconds.
The method of claim 1, wherein the plasma is atmospheric pressure plasma.
The method of claim 1, wherein the tire cord yarn comprises a polyester polymer, a polyamide polymer, a regenerated cellulose polymer, a polyolefin ketone polymer or a polyvinyl alcohol polymer.
The method of claim 1, wherein the adhesive comprises a RFL resin obtained by reacting 5 to 35% by weight of resorcinol, 2 to 10% by weight of formaldehyde and 60 to 90% by weight of rubber latex. 9. The method of claim 8, wherein the adhesive is a solution in which the RFL resin is dissolved at a concentration of 15 to 30% by weight.
The method of claim 1, wherein the RFL adhesive treatment step is performed within 6 hours after the plasma treatment step.
A tire comprising a tire cord made by the method of claim 1.

Images