KR20050026721A - Tire compound with high purity zno - Google Patents

Abstract

Provided is a rubber composition for a tire having high purity zinc oxide which decrease content of impurities like lead and cadmium with increasing surface area and reducing particle size, therefore it uses smaller amount of zinc oxide than the preexisted tire to satisfy physical properties of the tire. The rubber composition for the tire having high purity zinc oxide is characterized by including 1-1.5wt% of zinc oxide with 4.4-4.6m^2/g in surface area and 200-250nm in particle size having 0.0009 and less in lead content and 0.0002 and less in cadmium content by 100wt% of raw materials which are possibly selected from natural rubber, synthetic rubber, complex rubber of two or more synthetic rubbers and complex rubber of natural rubber and synthetic rubber.

Description

Tire compound with high purity ZnO

The present invention relates to a rubber composition for tires containing high purity zinc oxide, and more particularly, to include high purity zinc oxide having reduced contents of environmental harmful components lead (Pb), cadmium (Cd) and the like in the rubber composition. It relates to an environmentally friendly rubber composition for tires.

In general, most of the tire development can be concentrated on the structural aspects of the tire and the development of application technology of materials that can be used as a raw material of the tire. In the material sector of dual tires, most research has been conducted on the development of tires that emphasize energy saving and environmental issues.

In the field of rubber products such as tires, vulcanization is an essential process, and vulcanizing agents are used for such vulcanization, and vulcanization accelerators are added to the rubber composition to assist the vulcanizing agent. Meanwhile, in the tire production field, zinc oxide or stearic acid is mainly used as an activator to further improve the effect of the vulcanization accelerator during vulcanization, a tire production process.

Most vulcanization accelerators are amphoteric substances, and without zinc oxide (ZnO), the vulcanizing agent cannot exert its promoting effect. Even in the past when the promoter was not known, zinc oxide as an inorganic accelerator played a major role. Zinc oxide is strengthened depending on the size of the particle, such as activation strength or ultrafine active zinc.

In the tire industry, zinc oxide typically has a lead content of 0.4, a cadmium content of 0.05, a surface area of 4.3 m ² / g or less, and a particle size of 300 to 400 nm. However, EU environmental regulations set the maximum lead content in the product to 0.1 and the maximum cadmium content to 0.006. Therefore, in order to supply tires to Europe, it is necessary to apply zinc oxide as a new activator.

The present invention aims to reduce the content of impurities by using zinc oxide having a reduced lead and cadmium content and to provide an environmentally friendly rubber composition for tires in order to solve the problems mentioned above.

In addition, the present invention can increase the surface area compared to the zinc oxide commonly used in the conventional rubber composition for tires, it is possible to improve the acceleration effect of the vulcanization accelerator by using a reduced particle size, even if the amount of zinc oxide reduced the conventional oxidation It is another object of the present invention to provide a rubber composition for a tire that can exhibit physical properties equivalent to or higher than that of zinc-added rubber.

The present invention is a tire composition containing 1 to 1.5 parts by weight of zinc oxide having a lead content of 0.0009 or less and a cadmium content of 0.0002 or less in 100 parts by weight of the raw rubber in the known rubber composition for achieving the above-mentioned object. It includes a rubber composition for. In this case, zinc oxide may have a surface area of 4.4 to 4.6 m ² / g and a particle size of 200 to 250 nm.

The raw material rubber in the present invention can be used as long as it can be used as the raw material rubber of the rubber composition for a conventional tire. As an example of such raw rubber, in the present invention, synthetic rubber such as natural rubber, styrene butadiene rubber, butadiene rubber, styrene butadiene rubber containing isoprene, styrene butadiene rubber containing nitrile, and neoprene rubber may be used alone, or two or more synthetic rubbers may be used. It is possible to use mixed rubber in which rubber is mixed in the same ratio, or mixed rubber in which natural rubber and synthetic rubber are mixed in a ratio of 1: 9 to 9: 1.

In the present invention, the zinc oxide used to improve the promoting effect of the vulcanization accelerator has a lead content of 0.0009 or less, preferably a lead content of 0.0001 to less than or equal to the EU environmental regulations (lead maximum content 0.01, cadmium maximum content 0.006). It is 0.0009 and cadmium content is 0.0002 or less, More preferably, the cadmium content is used 0.00005-0.0002. In addition, the zinc oxide used in the present invention can improve the promoting effect of the vulcanization accelerator by using the surface area is increased and the particle size is reduced compared to the zinc oxide commonly used in conventional rubber compositions for tires. With such zinc oxide, those having a surface area of 4.4 to 4.6 m ² / g and particle size of 200 to 250 nm can be used. In order to achieve the object of the present invention, zinc oxide having various surface areas and particle sizes may be used in the present invention.

In the present invention, zinc oxide having a lead content of 0.0009 or less, a cadmium content of 0.0002 or less, a surface area of 4.4 to 4.6 m ² / g, and a particle size of 200 to 250 nm includes 1 to 1.5 parts by weight based on 100 parts by weight of the raw material rubber. do. When the zinc oxide content is added less than 1 part by weight, the vulcanization accelerator is insufficient to activate the vulcanization accelerator, so that the vulcanization promoting effect of the vulcanization accelerator is insignificant. Therefore, the present invention preferably uses 1 to 1.5 parts by weight of zinc oxide having the characteristics described above with respect to 100 parts by weight of the raw material rubber.

According to the present invention, various additives such as reinforcing fillers, activators, anti-aging agents, process oils, vulcanizing agents, and vulcanization accelerators, which are used in rubber compositions for tires, in addition to the raw material rubbers and zinc oxides mentioned above are appropriately selected as necessary. It can be used as a content. However, these are general components used in a rubber composition for a tire and are not essential components of the present invention.

On the other hand, the present invention includes a tire containing a rubber produced by the rubber composition for tires. In this case, the tire includes any one selected from a tire for a vehicle, a tire for a truck, and a tire for a bus.

Hereinafter, the present invention will be described by the following comparative examples, examples and test examples. However, these are not limited to the scope of the present invention by these as an embodiment of the present invention.

<Example 1>

90 parts by weight of natural rubber and 10 parts by weight of neoprene rubber, 1.5 parts by weight of zinc oxide, 1 part by weight of phenolic resin, 2 parts by weight of Resocinol resin, hexa Hexamethoxy Methyl Melamine 3.7 parts by weight, carbon black (N326) 65 parts by weight, stearic acid 1.5 parts by weight, dicyclohexyl-2-benzothiazol-sulfenamide 0.8 parts by weight, sulfur 4.7 Parts by weight, 0.7 parts by weight of cobalt salt (containing 23% cobalt) and 4.0 parts by weight of the process oil were placed in a Banbury mixer and cured at 160 ° C. for 25 minutes to prepare a belt rubber for a passenger car.

In the above zinc oxide was used as the lead content of 0.0009, cadmium content of 0.0002, surface area of 4.45 ± 0.05 m ² / g, particle size of 220 ± 10 nm.

Comparative Example 1

Conventionally, except that 3 parts by weight of zinc oxide having a lead content of 0.4, a cadmium content of 0.05, a surface area of 4.1 ± 0.2 m ² / g, and a particle size of 400 ± 10 nm is added as an active agent of a belt rubber for a passenger car. Belt rubber for a passenger car was manufactured using the same composition and method as in Example 1.

<Example 2>

100 parts by weight of raw rubber consisting of 70 parts by weight of natural rubber, 30 parts by weight of styrene butadiene rubber, 50 parts by weight of carbon black, 1.3 parts by weight of zinc oxide, 2 parts by weight of stearic acid, 4 parts by weight of anti-aging agent (kumanox-RD, Kumho Petrochemical) , 1.5 parts by weight of sulfur and 1.4 parts by weight of vulcanization accelerator (N-cyclohexyl-2-benzothiazolsulfen amide, CZ) were placed in a Banbury mixer and vulcanized at 160 ° C. for 25 minutes to prepare a truck and bus cap tread rubber.

In the above zinc oxide was used as the lead content of 0.0009, cadmium content of 0.0002, surface area of 4.45 ± 0.05 m ² / g, particle size of 240 ± 10 nm.

Comparative Example 2

Conventionally, 3.3 parts by weight of zinc oxide having a lead content of 0.4, a cadmium content of 0.05, a surface area of 4.0 ± 0.2 m ² / g, and a particle size of 380 ± 10 nm is added as an active agent of a truck and bus cap tread rubber. The belt rubber for passenger cars was manufactured using the same composition and method as in Example 1.

<Test Example 1>

Belt rubber for passenger cars obtained in Example 1 and Comparative Example 1 according to ASTM-related regulations (Rheo), Mooney (Mooney), tensile properties, heat built up (HBU), blow-out ( Blow-out), T-test properties such as measured and the results are summarized in Table 1 below.

Table 1. Car Belt Rubber Properties

Item Comparative Example 1 Example 1 Rheo (160 ℃) TOQ (max) 43.0 47.0 TOQ (min) 12.9 12.0 T40 5.08 5.08 T90 9.74 9.48 End cure (EC) 10.71 10.43 Mooney (125 ℃) viscosity 69 67 T05 22.53 21.33 T35 29.20 27.47 Mooney viscosity (100 ℃) 80 80 Tensile Properties Hardness 71 72 300% modulus 151 171 The tensile strength 246 231 Elongation 459 396 Fever (HBU) Temp. Rise 31.0 28.7 Comp. Set 94.8 97.6 Blow-out (50 ° C) 7.7 25.6 T-testfor. (Kg) / cov. (%) initial 55.97 / 90 48.04 / 75 over cure 47.12 / 90 48.52 / 70 T-5 52.88 / 90 52.11 / 85 H-5 56.21 / 90 49.61 / 70 G-5 47.40-90 34.25 / 70

<Test Example 2>

Cap tread rubber for trucks and / or buses obtained in Example 2 and Comparative Example 2 according to ASTM regulations, Leo, Mooney, tensile properties, heat generation (HBU), blow- Physical properties such as out and wear were measured, and the results are shown in Table 1 below.

Table 2. Cap Tread Rubber Properties for Trucks and / or Buses

Item Comparative Example 2 Example 2 Rheo (160 ℃) TOQ (max) 33.5 33.9 TOQ (min) 8.8 8.9 T40 6.14 7.35 T90 9.21 10.15 End cure (EC) 10.13 1.16 Mooney (125 ℃) viscosity 45 54 T05 30.93 41.6 T35 34.4 45.87 Mooney viscosity (100 ℃) 66 67 Tensile Properties Hardness 70 70 300% modulus 128 141 The tensile strength 205 191 Elongation 447 390 Heat built up Temp. Rise 33.2 32.7 Comp. Set 92.5 96.0 Blow-out (50 ° C) 14.6 13.0 Wear (pico) 0.0325 0.0315

As shown in Table 1 and / or Table 2, the rubber of Examples 1 and 2, which has a small amount of impurities such as lead and cadmium, has a large surface area, and has a small particle size, according to the present invention, has conventionally used zinc oxide. It can be seen that it has physical properties equivalent to or higher than that of Comparative Example 1 and Comparative Example 2.

The rubber composition for tires according to the present invention is less environmentally friendly due to less lead and cadmium, which is less contaminant than the rubber composition for tires. .

As described above, although described with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and modified within the scope of the present invention without departing from the spirit and scope of the present invention described in the claims below. It will be appreciated that it can be changed.

Claims (3)

In a known rubber composition for tires, A rubber composition for tires containing high purity zinc oxide, characterized by containing 1 to 1.5 parts by weight of zinc oxide having a lead content of 0.0009 or less and a cadmium content of 0.0002 or less with respect to 100 parts by weight of the raw rubber. The rubber composition for tires according to claim 1, wherein the zinc oxide has a surface area of 4.4 to 4.6 m ² / g and a particle size of 200 to 250 nm. A tire comprising a rubber produced by the rubber composition for tires according to claim 1.