KR100757889B1 - Tread rubber composition for tire - Google Patents

Abstract

A rubber composition for a tire tread is provided to improve dispersion and to lower a manufacturing cost by using cheap yellow soil and waste calcium triphosphate. A rubber composition comprises 2-15 parts by weight of yellow soil; and 2-10 parts by weight of calcium triphosphate based on 100 parts by weight of a rubber material. Preferably the yellow soil is heat treated at a high temperature of 700 deg.C or more for 1 hour or more; and the calcium triphosphate is the waste calcium triphosphate obtained after the polymerization of a foamed polystyrene resin and is used after left alone at a temperature of 80-200 deg.C for 1 hour or more.

Description

Rubber composition for tire treads {TREAD RUBBER COMPOSITION FOR TIRE}

The present invention relates to a rubber composition for tire treads, and more particularly, to a rubber composition for tire treads having excellent dispersibility because it is made of clay and tricalcium phosphate, which are relatively easy to obtain and inexpensive and have a large cost reduction effect. will be.

Fillers are added during rubber blending to provide reinforcement of tire treads. These fillers are currently carbon black and silica, and selected from products having various physical properties depending on the required characteristics of the tire and used alone or in part.

Such fillers are added to the tread rubber composition in an excessive amount in the range of about 10 to 80 parts by weight, but are usually expensive and cause a cost increase. Therefore, if it is possible to replace some of the materials with excellent physical properties and economical efficiency as a filler, it will be able to greatly reduce the cost and enhance domestic and international competitiveness in the tire industry.

On the other hand, it has been reported that ocher was used as a filler in addition to carbon black and silica, but this has a problem of poor dispersibility.

In order to solve the above problems, an object of the present invention is to provide a rubber tread rubber composition having improved dispersibility by using tricalcium phosphate together with ocher as a filler in the rubber tread composition.

The rubber composition for tire treads according to the present invention is characterized in that it comprises 2 to 15 parts by weight of ocher and 2 to 10 parts by weight of tricalcium phosphate based on 100 parts by weight of the raw material rubber.

In the tire tread rubber composition of the present invention, the raw material rubber may be natural rubber or synthetic rubber or a mixture of natural rubber and synthetic rubber, and there is no particular limitation on the type of natural rubber and synthetic rubber.

The loess used in the present invention contains a component such as sand and a large amount of calcium carbonate, which is not easily broken, and has a viscous force, which is effective as a filler to replace silica or carbon black, which has an average particle size of 0.02 to It is composed of various particles of 0.05mm, and the chemical composition includes 60 to 70% by weight of silica, 10 to 20% by weight of alumina, 5 to 6% by weight of iron, about 2% by weight of magnesium, about 2% by weight of potassium and lime It is composed of about 8% by weight, the mineral composition is composed of 60 to 70% by weight of quartz, 10 to 20% by weight of feldspar and mica, 5 to 35% by weight of carbonate mineral and 2 to 5% by weight of silt.

Since natural yellow soil contains a large amount of organic substances, it is preferable to remove these organic substances and use them. The method for removing these organics may include a heat treatment at a high temperature of 700 ℃ or more. The high temperature heat treatment process is not particularly limited, and, for example, it is preferable to leave at least one hour in a state of 700 ° C. or more under oxygen conditions using a known electric furnace.

It is preferable to use 2 to 15 parts by weight of the loess, but less than 2 parts by weight is not preferable because the filler effect of the carbon substitute is not expressed, and if it exceeds 15 parts by weight, there is a problem that the tensile property is lowered, which is not preferable.

As the tricalcium phosphate used in the present invention, waste tricalcium phosphate used and discarded in the polymerization of the expanded polystyrene resin, which is a raw material of styrofoam, may be used. The effect of reducing can also be obtained at the same time.

Since the waste tricalcium phosphate used in the present invention preferably does not have moisture in the rubber composition, it is preferable to use the waste tricalcium phosphate after leaving it for about 1 hour or more, preferably 1 to 5 hours at a temperature of about 80 to 200 ° C. Do.

It is preferable to use 2 to 10 parts by weight of the tricalcium phosphate, but less than 2 parts by weight is not preferable because the cost-saving effect is weak, and exceeding 10 parts by weight is not preferable because it causes a decrease in tensile properties.

In addition, the rubber composition of the present invention may include other additives and compounding agents used in conventional rubber tread rubber compositions, for example fillers, anti-aging agents, active agents, vulcanizing agents, vulcanization accelerators, process oils, etc. to be.

The present invention can be understood in more detail by the following examples and comparative examples, the following examples are only for illustrating the present invention, and are not intended to limit the protection scope of the present invention.

Example  And Comparative example

Comparative Example 1

As shown in Table 1 below, a rubber composition was prepared by blending 20 parts by weight of aromatic oil, 50 parts by weight of carbon black, 5 parts by weight of ocher, 2 parts by weight of sulfur, and 1.5 parts by weight of vulcanization accelerator, based on 100 parts by weight of natural rubber, It was vulcanized at 160 ° C. to prepare a rubber specimen. Evaluation items such as viscosity, tensile strength, 300% modulus, hardness, and exothermic properties of the rubber specimens were measured, and the results are shown in Table 1 together.

<Example 1>

As shown in Table 1, 20 parts by weight of aromatic oil, 50 parts by weight of carbon black, 5 parts by weight of ocher, 2 parts by weight of waste tricalcium phosphate, 2 parts by weight of sulfur, and 1.5 parts by weight of vulcanization accelerator based on 100 parts by weight of natural rubber The rubber composition was prepared by mixing and vulcanizing it at 160 ° C. to prepare a rubber specimen. Evaluation items such as viscosity, tensile strength, 300% modulus, hardness, and exothermic properties of the rubber specimens were measured, and the results are shown in Table 1 together.

<Example 2>

A rubber specimen was prepared in the same composition and method as in Example 1 except that 5 parts by weight of waste tricalcium phosphate was used.

<Example 3>

A rubber specimen was prepared in the same composition and method as in Example 1 except that 10 parts by weight of waste tricalcium phosphate was used.

Comparative Example 2

A rubber specimen was prepared in the same composition and method as in Example 1 except that 15 parts by weight of waste tricalcium phosphate was used.

Table 1

                                                   (Unit: weight part)

Furtherance Comparative Example 1 Example 1 Example 2 Example 3 Comparative Example 2 Natural rubber 100 100 100 100 100 Aromatic Oil 20 20 20 20 20 Carbon black 50 50 50 50 50 Ocher ^{1 )} 5 5 5 5 5 Waste tricalcium phosphate ^{2 )} - 2 5 10 15 brimstone 2 2 2 2 2 accelerant 1.5 1.5 1.5 1.5 1.5 Pattern viscosity (125 ℃) 73 73 70 72 74 Tensile Strength (kg / cm ² ) 148 150 155 150 140 300% modulus (kg / ㎠) 355 359 362 350 349 Hardness (shore A) 74 74 75 80 82 Exothermic characteristics 28 26 24 25 29

Note: 1) Use after heat treatment at 700 ℃ for 1 hour.

    2) Use after 5 hours at 80 ℃.

As shown in Table 1, compared to the rubber composition of Comparative Example 1, the rubber compositions of Examples 1 to 3 showed an improvement effect in viscosity, modulus, hardness, tensile strength and exothermic properties, waste tricalcium phosphate 10 In Comparative Example 2, which is used more than two parts, it can be seen that the tensile strength is lower than that of Examples 1 to 3.

As described above, it can be seen that the rubber composition for tire treads of the present invention is excellent in viscosity, modulus, hardness, tensile strength and exothermic properties by improving dispersibility. In addition, the use of relatively easy and inexpensive loess has a high cost saving effect, and the use of waste tricalcium phosphate, an environmentally hazardous waste formed during the production of expanded polystyrene, results in a lower viscosity and improved processability and improved scorch characteristics. In addition, it is possible to contribute to improving the durability of the tire due to the excellent heat generation characteristics. In addition, by utilizing waste tricalcium phosphate that can be discharged as an environmentally harmful substance, the effect of recycling and reducing environmentally harmful substances can also be obtained.

Claims (3)

A rubber composition for a tire tread, comprising 2 to 15 parts by weight of ocher and 2 to 10 parts by weight of tricalcium phosphate based on 100 parts by weight of the raw material rubber. The rubber composition for tire treads according to claim 1, wherein the loess is heat-treated at 700 ° C or higher for at least 1 hour. The rubber composition for a tire tread according to claim 1, wherein the tricalcium phosphate is waste tricalcium phosphate after being used for polymerization of the expanded polystyrene resin, and is used after being left at 80 to 200 ° C for at least 1 hour.