KR101336600B1 - Rubber composition for reparing tire and tire manufactured by using the same - Google Patents

Abstract

The present invention relates to a rubber composition for tire repair and a tire manufactured using the same, wherein 100 parts by weight of the raw material rubber including natural rubber, a nitrogen adsorption specific surface area of 70 to 100 m ² / g, and a DBP oil absorption of 100 to 130 cc / 40 g to 50 parts by weight of 100 g of carbon black, 5 to 8 parts by weight of insoluble sulfur, and cobalt naphthenate (co-naph), cobalt boro acylate and combinations thereof It includes any one cobalt salt, wherein the cobalt salt is provided to the rubber composition for tire repair is added so that the content of cobalt is 0.2 to 0.45 parts by weight.

The rubber composition for repairing tires of the present invention has excellent adhesion to the steel exposed portion, has suitable physical properties in accordance with the rigidity of the belt portion, etc., and also has excellent co-curing properties with the surrounding rubber, and thus has excellent physical properties, adhesiveness, and processability. .

Tire, Recycled Tire, Repair, Steel Bonding, Natural Rubber, Carbon Black, Insoluble Sulfur, Cobalt Salt, Cobalt Naphthenate, Cobalt Borosilicate, Adhesion, Stiffness, Physical Properties, Processability

Description

RUBBER COMPOSITION FOR REPARING TIRE AND TIRE MANUFACTURED BY USING THE SAME

The present invention relates to a rubber composition for tire repair and a tire manufactured using the same, wherein the tire repair rubber composition applicable to a steel exposed portion of a tread worn tire when a regenerated tire is manufactured, and a tire manufactured using the same. It is about.

Worn cases of tires for trucks or buses used as recycled tires are partially exposed to steel depending on the conditions of use. Moreover, in the aftermath of the economic recession, the quality of the casings used as recyclable tires is getting worse and more repaired. In this case, the poor adhesion between the repaired portion of the regenerated tire and the rubber for repairing the steel exposed portion may act as a direct factor that leads to a decrease in durability of the regenerated tire.

The regenerated tire is a new tread rubber attached to the high tire through the vulcanization process, and there are two regeneration methods of hot cure and cold cure. Cold Cure requires more casing under tread gauges to remain in the manufacturing process, which typically results in good quality casing and fewer steel exposed parts.

On the other hand, the hot cure method has a wide reproducible range of the case, but the quality of the case is deteriorated accordingly it requires more attention to repair the case. Since the hot cure method can reproduce the case in which the under-tread gauge is hardly left, the steel exposed part is often required to be repaired.

In this case, when the repair rubber composition used generally is exposed to the steel, due to the low adhesion between the steel and the repair rubber, which are completely different in properties, the adhesion may be separated according to the fatigue accumulation of the tire while driving. This tread separation is likely to lead to large accidents. Therefore, it can be said that the adhesive force between the tire repair rubber composition and the steel has a decisive influence on the durability performance of the recycled tire.

However, the development of repair rubber compositions has not been smoothly developed due to the management difficulties due to the dualization of rubber and steel exposed part repair rubbers used in the manufacture of recycled tires and the technical difficulties of recycling companies for the special properties of rubber compounding compositions. Can not do it. Accordingly, the defective rate of the recycled tire is high, and the quality expectation level for the overall recycled tire is low.

In addition, the rubber used for the belt (belt) portion as well as the adhesion to the steel should have a certain or more rigidity, the formulation to increase the rigidity of the rubber is generally poor workability and suffers from process difficulties in the regeneration process. Therefore, the demand for the rubber composition for tire repair which balanced the physical property and workability is increasing.

Thus, in order to secure the durability performance of the regenerated tire, it is necessary to secure the adhesive strength between the steel exposed portion and the repair rubber, which are difficult to obtain in general repair rubber compositions, and have the most suitable physical properties in consideration of the rigidity of the belt portion, and do not degrade the workability. There is a need for the development of formulated rubbers for repairing steel exposed parts.

An object of the present invention is a tire repair rubber composition having excellent adhesion to the steel exposed portion, suitable physical properties to match the rigidity of the belt portion, etc., excellent co-curing properties with the surrounding rubber, and excellent physical properties, adhesiveness and processability. To provide.

It is another object of the present invention to provide a tire manufactured using the tire repair rubber composition.

In order to achieve the above object, the rubber composition for tire repair according to an embodiment of the present invention is 100 parts by weight of the raw material rubber containing natural rubber, nitrogen adsorption specific surface area of 70 to 100m ² / g, DBP (n-dibutyl phthalate 40 to 50 parts by weight of carbon black oil absorption of 100 to 130cc / 100g, 5 to 8 parts by weight of insoluble sulfur, and Cobalt Naphthenate (CO-NAPH), Cobalt Boro Acylate and It includes any one cobalt salt selected from the group consisting of a combination thereof, the cobalt salt is added so that the content of cobalt is 0.2 to 0.45 parts by weight.

The tire repair rubber composition may further include 0.7 to 0.9 parts by weight of N, N-dicyclohexyl-2-benzothiazylsulfenamide (DCBS) vulcanization accelerator.

The tire repair rubber composition may further include 1 to 4 parts by weight of 2,2,4-trimethyl-1,2-dihydroquinoline (TMDQ) antioxidant.

The tire repair rubber composition may further include 1 to 4 parts by weight of an N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine (6PPD) ozone inhibitor.

The tire repair rubber composition may further include 1 to 4 parts by weight of p-alkyl phenol formaldehyde resin.

A tire according to another embodiment of the present invention is manufactured using the tire repair rubber composition.

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

The rubber composition for tire repair is 100 parts by weight of raw rubber including natural rubber, nitrogen adsorption specific surface area of 70 to 100m ² / g, 40 to 50 parts by weight of carbon black with DBP oil absorption of 100 to 130cc / 100g, insoluble sulfur 5 to 8 parts by weight and any one cobalt salt selected from the group consisting of Cobalt Naphthenate (CO-NAPH), Cobalt Boro Acylate, and combinations thereof.

The tire repair rubber composition uses natural rubber as a raw material rubber to maintain the rigidity of the rubber. In the case of using synthetic rubber other than natural rubber as the raw material rubber, rubber physical properties such as tensile strength and toughness may be reduced.

The carbon black has a nitrogen adsorption specific surface area (N ₂ SA, nitrogen surface area per gram) of 70 to 100 m ² / g and a DBP (n-dibutyl phthalate) oil absorption of 100 to 130 cc / 100 g, which is highly rigid and colloidal. It is preferable to use carbon black having properties.

When the N ₂ SA value of the carbon black exceeds 100 m ² / g, there is an advantageous surface for the reinforcement of rubber properties, but the processability of the rubber repair rubber composition may be detrimental, and the filler may be less than 70 m ² / g. Reinforcement by carbon black may be reduced.

If the DBP oil absorption of the carbon black exceeds 130cc / 100g, the processability of the tire repair rubber composition may be reduced, and if the DBP oil absorption of the carbon black is less than 100cc / 100g, the reinforcing performance by the carbon black filler may be disadvantageous. have.

Carbon black having the highly reinforcing colloidal properties are included in 40 to 50 parts by weight based on 100 parts by weight of the raw material rubber. If the content of the carbon black is less than 40 parts by weight, the physical properties of the rubber composition such as modulus and tensile strength may be lowered. If the content of the carbon black is more than 50 parts by weight, the processability of the rubber composition for tire repair is deteriorated, thereby repair-gun in the regeneration process. (repair-gun) is difficult to use, fatigue resistance and crack resistance may be reduced, it is difficult to obtain a repair rubber having sufficient rigidity when the carbon black having the high reinforcement colloidal (colloidal) properties are not used.

The tire repair rubber composition includes insoluble sulfur in an amount of 5 to 8 parts by weight based on 100 parts by weight of the raw material rubber as a vulcanizing agent. When powder sulfur is used in addition to the insoluble sulfur as the vulcanizing agent, surface precipitation of sulfur may occur, which may result in deterioration of adhesion performance of a surface to be repaired with a tread and cushion gum.

When the content of the insoluble sulfur is less than 5 parts by weight based on 100 parts by weight of the raw material rubber, adhesion to the surrounding rubber is reduced or modulus is lowered due to deterioration of co-current properties, resulting in separation due to the difference in rigidity with the belt rubber. Problems such as this may occur, and if it exceeds 8 parts by weight, problems such as deterioration of heat resistance and oxygen aging resistance and toughness may occur.

The tire repair rubber composition may further include a vulcanization accelerator. The vulcanization accelerator has the best vulcanization properties and covalent properties, and N, N-dicyclohexyl-2-benzothiazylsulfenamide (N, N-dicylcohexyl-2-) that can secure sufficient vulcanization rate and physical properties. benzothiazolyl sulfonamide, DCBS) can be preferably used.

The vulcanization accelerator may be included in an amount of 0.7 to 0.9 parts by weight based on 100 parts by weight of the raw material rubber. When the content of the vulcanization accelerator is out of the above range, not only the physical properties and adhesion of the rubber repair rubber composition may be lowered, but also the co-curing property with the surrounding rubber may be disadvantageous.

The tire repair rubber composition further includes any one cobalt salt selected from the group consisting of cobalt naphthenate, cobalt boro acylate, and combinations thereof, thereby further improving adhesion to tire steel cords. The cobalt naphthenate may be preferably used with a cobalt content of 10% by weight, and the cobalt boro acylate may be preferably used with a cobalt content of 22.5% by weight, but the present invention is not limited thereto. .

The cobalt salt may be added so that the content of cobalt is 0.2 to 0.45 parts by weight based on 100 parts by weight of the raw material rubber. When the content of cobalt is less than 0.2 parts by weight, a marked decrease in adhesion of the rubber repair rubber composition may appear. When the content of the cobalt is more than 0.45 parts by weight, the effect of additional adhesion is hardly exhibited. Only can be raised.

When using cobalt naphthenate having a cobalt content of 10% by weight, the cobalt naphthenate may be included in an amount of 2 to 4 parts by weight based on 100 parts by weight of the raw material rubber, and the cobalt content is 22.5. When the cobalt boro acylate is used in the weight percent of the cobalt boro acylate may be included in 1 to 2 parts by weight based on 100 parts by weight of the raw material rubber.

In addition, the tire repair rubber composition may further include a resin (resin) to further improve the tack performance between the rubber (rubber) and the rubber. The resin not only increases the adhesion of the rubber but also improves the mixing, dispersibility and processability of other additives such as fillers, thereby contributing to the improvement of physical properties of the rubber.

In particular, the resin can be preferably used p-alkyl phenol formaldehyde resin in consideration of the improvement of co-current performance through improved adhesion performance, specifically p-tert-butyl-phenol formaldehyde resin, p-tert- Any one selected from the group consisting of octyl-phenol formaldehyde and combinations thereof can be used.

The resin may be included in 1 to 4 parts by weight based on 100 parts by weight of the raw material rubber. When the content of the pressure-sensitive adhesive is less than 1 part by weight based on 100 parts by weight of the raw material rubber, the adhesive performance may be detrimental.

The tire repair rubber composition may further include an anti-aging agent used to stop the chain reaction in which the tire is automatically oxidized by oxygen or ozone. In particular, the antioxidant is 2,2,4-trimethyl-1,2-dihydroquinoline (TMDQ) as an antioxidant or N- (1,3-dimethylbutyl) -N'-phenyl-p-phenyl as an ozone inhibitor Rendiamine (6PPD) can be preferably used.

The antioxidant and the ozone inhibitor may be included in an amount of 1 to 4 parts by weight, and preferably 1 to 2 parts by weight, based on 100 parts by weight of the raw material rubber. When the antioxidant and the ozone inhibitor are included in the content range, it is possible to secure weather resistance against oxygen and ozone that penetrates the rubber for tire repair, and may also have an effect on preventing oxidation of steel.

Oxidation of the steel not only lowers the stiffness of the steel itself, but also decreases the adhesiveness with the rubber, which may greatly affect the durability of the tire. Particularly, in the case of a regenerated tire, the steel in the tire may be partially oxidized. Because of the high probability, the suppression of oxidation progression is more important.

The tire repair rubber composition may optionally further include a variety of additional additives. The various additives can be used as long as it is commonly used in the field to which the present invention belongs, the content thereof is not particularly limited, depending on the compounding ratio used in the conventional tire repair rubber composition.

A tire according to another embodiment of the present invention is manufactured using the tire repair rubber composition. The method of manufacturing a tire using the tire repair rubber composition may be applied to any method used in the manufacture of a tire in the related art, and thus, detailed description thereof will be omitted.

However, the tire may be a reclaimed tire, and the steel exposed portion of the tire may be repaired using the tire repair rubber composition, and the regenerated tire may be regenerated by a hot cure or cold cure regeneration method. It may be.

The rubber composition for repairing tires of the present invention has excellent adhesion to the steel exposed portion, has suitable physical properties in accordance with the rigidity of the belt portion, etc., and also has excellent co-curing properties with the surrounding rubber, and thus has excellent physical properties, adhesiveness, and processability. .

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[Production Example: Production of Rubber Composition]

To prepare a rubber composition for tire repair according to the Example and Comparative Example using the composition shown in Table 1. Preparation of the rubber composition for tire repair followed the conventional method for producing a rubber composition for tire repair.

In the following Table 1, Comparative Example 1 is the case of the addition of excess CO-NAPH, Comparative Example 2 is the case of not adding CO-NAPH, Comparative Example 3 is the case of using the powdered sulfur of the same sulfur content instead of insoluble sulfur .

[Table 1] (Unit: parts by weight)

Compounding agent Example Comparative Example 1 Comparative Example 2 Comparative Example 3 Natural rubber 100 100 100 100 Carbon Black ^① 45 45 45 45 Zinc oxide 4 4 4 4 Stearic acid 2 2 2 2 Fire retardant (oxidation ^② / ozone ^③ ) 1/2 1/2 1/2 1/2 Resin ^④ 3 3 3 3 Cobalt Salt ^⑤ 3 5 - 3 Insoluble Sulfur / Powder Sulfur 6 /- 6 /- 6 /- -Of 6 Vulcanization accelerator ^⑥ One One One One

① Carbon Black: Carbon black with nitrogen adsorption specific surface area of 70-100 m ² / g and DBP oil absorption of 100-130cc / 100g

② Antioxidant: 2,2,4-trimethyl-1,2-dihydroquinoline (TMDQ)

③ Ozone inhibitor: N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine (6PPD)

④ resin: p-octyl phenol formaldehyde resin

⑤ cobalt salt: cobalt-naphthenate (CO-NAPH, Co content 10% by weight)

⑥ Acceleration accelerator: N, N-dicyclohexyl-2-benzothiazylsulfenamide (DCBS)

Experimental Example: Measurement of Physical Properties of Prepared Rubber Composition

Using the rubber composition prepared in Examples and Comparative Examples, the vulcanization time and physical properties and the adhesion between the steel (steel) and the rubber was measured, the results are shown in Table 2 below. The vulcanization temperature was 150 ° C.

[Table 2]

Compounding agent Example Comparative Example 1 Comparative Example 2 Comparative Example 3 Torque 31.3 30.5 31.4 32.1 Mooney viscosity 47 49 46 48 Adhesion (kg) 2.5 2.3 2.5 1.6 Tensile Strength (Index) 100 98 100 95 Fracture Strength (Index) 100 101 102 94 Fatigue Resistance (Index) 100 95 103 92 Crack Resistance (Index) 100 97 102 93 Adhesive force between rubbers (kg) 57 54 57 43 Rubber-Steel Adhesion (kg) 28 29 11 23

The maximum torque was measured by the method according to ASTM standard D2705, and the higher the value, the more favorable the result.

Mooney viscosity (ML1 + 4 (125 ° C.)) was measured according to SMS ASTM specification D1646. Mooney viscosity is a value indicating the viscosity of the unvulcanized rubber, the lower the value indicates that the workability of the unvulcanized rubber is excellent.

Adhesion (tack) represents the adhesive force between the unvulcanized rubber (repair rubber) and the vulcanized rubber, measured according to the ASTM standard D5668 and indexed based on the example, the higher the numerical value, the more favorable the result.

Tensile strength was measured by the method of ASTM D 790 and indexed based on the example, the higher the value is the more favorable results.

Fracture strength was measured according to ASTM standard D624 and indexed based on the example. The higher the value, the more favorable the result.

Fatigue resistance was measured according to ASTM standard D4482 and indexed based on the example. The higher the value, the more favorable the result.

The crack resistance was measured according to ASTM standard D813-95 and indexed the number of cycles based on the examples. The higher the value, the more favorable the result.

The adhesive strength between rubbers is a result of measuring the interfacial adhesion after co-vulcanization of the unvulcanized rubber (repair rubber) and the vulcanized rubber, and the higher the value, the better the adhesive strength.

The rubber-steel adhesion is a result of measuring the adhesion between the rubber and steel in the same manner as the adhesion between the rubbers, and the higher the value, the better the adhesion.

Referring to Table 2, it can be seen that the Example shows excellent adhesion while having a good required physical properties compared to Comparative Examples 1 to 3.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

Claims (6)

100 parts by weight of raw rubber including natural rubber, 40-50 parts by weight of carbon black having a nitrogen adsorption specific surface area of 70 to 100 m ² / g and a DBP (n-dibutyl phthalate) oil absorption amount of 100 to 130 cc / 100 g, 5 to 8 parts by weight of insoluble sulfur, N, N-dicyclohexyl-2-benzothiazylsulfenamide (DCBS) vulcanization accelerator, 1 to 4 parts by weight of 2,2,4-trimethyl-1,2-dihydroquinoline (TMDQ) antioxidant, 1 to 4 parts by weight of an N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine (6PPD) ozone inhibitor, 1 to 4 parts by weight of p-alkyl phenol formaldehyde resin and Cobalt Naphthenate (CO-NAPH), Cobalt Boro Acylate (Cobalt Boro Acylate) and any one selected from the group consisting of a combination thereof, The cobalt salt is a rubber composition for tire repair is added so that the content of cobalt is 0.2 to 0.45 parts by weight. delete delete delete delete A tire manufactured using the rubber repair rubber composition according to claim 1.