KR100771701B1 - Tire tread rubber composition - Google Patents

Abstract

A rubber composition for tire treads is provided to satisfy the environmental standard defined by EU through the use of processing oil having a low PAH(polycyclic aromatic hydrocarbons) content while maintaining or improving physical properties. A rubber composition for tire treads comprises: 100 parts by weight of base rubber containing 20-55 parts by weight of solution polymerized styrene-butadiene rubber having a styrene content of 30-31% and a vinyl content of 31-36%, and 45-80 parts by weight of at least one rubber; 1-50 parts by weight of processing oil having a PAH content of less than 10 ppm; and 30-40 parts by weight of at least one filler selected from calcium carbonate, clay and talc.

Description

Tire tread rubber composition

The present invention relates to a tire tread rubber composition, and more particularly, to a solution-polymerized styrene-butadiene rubber having a styrene content of 31 to 37% and a vinyl content of 31 to 37%, and a raw material rubber comprising at least one rubber. A tire tread rubber composition comprising a process oil containing a low content of polycyclic aromatic hydrocarbon compounds (PAH).

As environmental issues have emerged as a major concern around the world since the 1990s, environmental regulations have been tightened around major developed countries such as Europe. By raising issues about environmental degradation such as global warming, ozone layer destruction and acid rain, we are strengthening various environmental regulations that can suppress such environmental destruction. In recent years, by linking trade and environmental issues in each country, even the survival of companies can be threatened without the development of eco-friendly products.

This trend is no exception to the tires of the car as well as the parts of the car. In other words, regulations on harmful substances are being tightened on raw materials of tires. In particular, in the case of tires, there is an increasing demand for chemicals that can be introduced into the ecosystem by dust, fine dust, and rain generated by wear, to be replaced with more environmentally friendly chemicals.

A typical example thereof is aromatic oil, which is a process preparation oil used to improve compatibility between rubber and reinforcing fillers in tires and to increase compounding processability.

The components of the process oil for tires are mainly composed of aromatic, naphthenic and paraffinic compounds. In general, aromatic oils are generally used as tire process oils. Polycyclic aromatic hydrocarbons (PAH) contained in aromatic oils are known as one of the germination substances. It is spreading slowly.

However, according to the environmental regulations of the European region, when using a process oil that satisfies the regulatory value of polycyclic aromatic hydrocarbon compound (PAH) content, there is a problem in that the performance of the existing rubber composition is not properly exhibited. Therefore, it is necessary to develop a rubber composition that uses a process oil containing a polycyclic aromatic hydrocarbon compound (PAH) that satisfies the regulation level and maintains a performance level equal to or higher than that of a conventional rubber composition.

In Europe, a legislation will be enacted that, from January 1, 2010, process oils containing the following ingredients should be banned and not used in the manufacture of tires.

-Bap 1 ppm (mg / kg) or more, or if the total content of PAH components listed below is 10 ppm (mg / kg) or more

-PAH (polycyclic Aromatic Hydrocarbons) List

a. Benzo (a) pyrene (BaP)

b. Benzo (e) pyren (BeP)

c. Benzo (a) anthracene (BaA)

d. Chrysen (CHR)

e. Benzo (b) fluoranthene (BbFA)

f. Benzo (j) fluoranthene (BjFA)

g. Benzo (k) fluoranthene (BkFA)

h. Dibenzo (a, h) anthracene (DBAhA)

Considering these regulatory conditions, the tire performance, which is one of the major export products in Korea, satisfies the regulation value of the PAH content in the process formula, and tire performance is comparable to that of conventional tires. It is an urgent situation, but there is not enough research on this yet.

Accordingly, the present invention seeks to develop a rubber composition for a tire having a performance equal to or higher than that of a conventional tire while satisfying the regulations of environmental regulations that are gradually strengthened.

The present invention provides a tire tread rubber composition using a process oil having a low polycyclic aromatic hydrocarbon compound (PAH) content in accordance with European environmental regulations, and can provide properties equal to or higher than those of a conventional tire tread rubber composition. An object is to provide a tire tread rubber composition.

In order to achieve the above-mentioned object, the present invention provides a tire-tread rubber composition comprising a solution-polymerized styrene-butadiene rubber having a styrene content of 30 to 36% and a vinyl content of 31 to 37%. A tire tread rubber composition comprising a process oil having a polycyclic aromatic hydrocarbon compound (PAH) content of less than 10 ppm relative to the raw rubber thus obtained is represented.

The tire tread rubber composition of the present invention is a raw material consisting of 20 to 90 parts by weight of a solution-polymerized styrene-butadiene rubber having a styrene content of 30 to 36% and a vinyl content of 31 to 37%, and 10 to 80 parts by weight of at least one rubber. A tire tread rubber composition containing 1 to 50 parts by weight of process oil having a polycyclic aromatic hydrocarbon compound (PAH) content of less than 10 ppm with respect to 100 parts by weight of rubber is shown.

In the raw material rubber of the present invention, at least one rubber may be used as a raw material rubber of a tire tread rubber composition in addition to the solution-polymerized styrene-butadiene rubber having a styrene content of 31 to 38% and a vinyl content of 50 to 57%. Anything can be used.

One or more selected from natural rubber or synthetic rubber may be used as one example of one or more rubbers among the raw material rubbers of the present invention.

As an example of at least one rubber in the raw material rubber of the present invention, a mixed rubber in which two or more synthetic rubbers are mixed may be used.

Synthetic rubber used as an example of at least one rubber in the raw material rubber of the present invention is styrene butadiene rubber, butadiene rubber, butyl rubber, halogenated butyl rubber, styrene butadiene rubber containing isoprene, styrene butadiene rubber containing nitrile, Any one or more selected from neoprene rubber may be used.

Process oil in the rubber composition of the present invention can be used treated distillate aromatic extracts (TDAE).

Tire tread rubber composition of the present invention is applied to the raw material rubber of various components, contents in the production of tire tread rubber composition containing a process oil having a polycyclic aromatic hydrocarbon compound (PAH) content of less than 10ppm in accordance with the environmental regulations of Europe. Preferably, when the raw rubber component of the tire tread rubber composition is 100 parts by weight, 20 to 90 parts by weight of a solution-polymerized styrene-butadiene rubber having a styrene content of 30 to 36% and a vinyl content of 31 to 37% and at least one rubber It is preferable to use 100 parts by weight of the raw material rubber consisting of 10 to 80 parts by weight.

The process oil having a polycyclic aromatic hydrocarbon compound (PAH) content of less than 10 ppm in the tire tread rubber composition of the present invention may be used in an amount of 1 to 50 parts by weight based on 100 parts by weight of the raw material rubber. Process oil containing less than 10ppm of polycyclic aromatic hydrocarbon compound (PAH) is insignificant to serve as process oil when used less than 1 part by weight based on 100 parts by weight of raw material rubber. There is no increase in the apparent effect, and there is a fear that the physical properties of the rubber is reduced. Therefore, the process oil having a polycyclic aromatic hydrocarbon compound (PAH) content of less than 10 ppm in the tire tread rubber composition of the present invention is preferably used in an amount of 1 to 50 parts by weight based on 100 parts by weight of the raw material rubber.

The present invention can be used in addition to the process oil as long as it can be used in the conventional tire tread rubber composition as a reinforcing filler.

In the present invention, as an example of the reinforcing filler, any one or more selected from carbon black, silica, calcium carbonate, clay, and talc may be used in an amount of 30 to 90 parts by weight based on 100 parts by weight of the raw material rubber.

As an example of the carbon black which is one of the reinforcing fillers above, an iodine moisture absorption amount is 85 to 95 mg / g, and a DBP oil absorption amount is 110 to 120 ml / 100 g.

As an example of silica, which is one of the reinforcing fillers, a BET value representing a surface area is 110 to 130 m ² / g, and a DOP adsorption amount representing a structure is 250 to 270 ml / 100 g.

Various components and contents are applied to the tire tread rubber composition of the present invention. In order to obtain a tire tread rubber composition consistent with the object of the present invention, the tire tread rubber composition of the above-mentioned components and contents is preferable.

According to the present invention, various additives such as anti-aging agents, activators, process oils, vulcanizing agents, and vulcanization accelerators, which are used in conventional tire tread rubber compositions, in addition to the raw rubbers, process oils, and reinforcing fillers mentioned above are appropriately selected as necessary. It can be used as a content. However, these are general components used in conventional tire tread rubber compositions, and thus are not essential components of the present invention, and thus the detailed descriptions thereof will be omitted.

The present invention includes a tire containing a rubber composed of the tire tread rubber composition described above.

The rubber made of the tire tread rubber composition of the present invention can be applied to the rubber part of the tire. One example of the application area of the tire can be applied to the tread area.

The tire containing the rubber made of the tire tread rubber composition is any one or more selected from passenger tires, truck tires, bus tires, motorcycle tires, and aircraft tires.

Hereinafter, the present invention will be described in more detail by the following Comparative Examples, Examples and Test Examples. However, these are only one example for the practice of the present invention, and the scope of the present invention is not limited thereto.

<Example>

40 parts by weight of solution-polymerized styrene butadiene rubber (solution polymerization SBR # 2) of Table 1, 40 parts by weight of emulsion-polymerized styrene butadiene rubber (E-SBR), and 100 parts by weight of raw material rubber consisting of 20 parts by weight of butadiene rubber 30 parts by weight of TDAE process oil having a content of PAH of 3.6 ppm, 30 parts by weight of silica, 4.8 parts by weight of silane coupling agent (SI-69), 45 parts by weight of carbon black, 3 parts by weight of zincated, 3 parts by weight of stearic acid, anti-aging agent 4 By weight and 2 parts by weight of wax were placed in a Banbury mixer and blended for 5 minutes to obtain a rubber blend.

Sulfur 2.0 parts by weight as a vulcanizing agent, 1.9 parts by weight of N-cyclohexyl-2-benzothiazole sulfenamide (CZ) as a vulcanizing agent, and 0.6 parts by weight of diphenylguanidine (DPG) in the rubber compound. The mixture was added and vulcanized at 160 ° C. for 20 minutes to prepare a rubber specimen.

In the carbon black, the iodine moisture absorption amount was 90 mg / g, and the DBP oil absorption amount was 115 ml / 100 g.

In the above, the silica had a BET value of 120 m ² / g and a DOP adsorption amount of 260 ml / 100 g.

Comparative Example

40 parts by weight of solution-polymerized styrene butadiene rubber (solution polymerization SBR # 1) of Table 1, 40 parts by weight of emulsion-polymerized styrene butadiene rubber (E-SBR), and 100 parts by weight of raw material rubber consisting of 20 parts by weight of butadiene rubber A rubber specimen was prepared in the same manner as in Example except that 30 parts by weight of DAE process oil having a PAH content of 280 ppm was used.

Table 1. Characteristics of the polymers used in the preparation of the rubber specimens of the Examples and Comparative Examples

division Solution polymerization SBR # 1 Solution polymerization SBR # 2 OIL TYPE Existing Process Oil Process oil with low PAH content of TDAE Type Tg -40 -40 Styrene (%) 31.0 33.0 Vinyl (%) 30.0 34.0

Table 2. Characteristics of Process Oils Used in the Preparation of Rubber Specimens of Examples and Comparative Examples

division Existing Process Oil Process oil with low PAH content of TDAE Type Remarks Type DAE TDAE PAH content (ppm) 280 3.6 8 kinds of European regulations Ca 37 25 Cp 19 30 Cn 44 45 Aniline point ('C) 43.5 65.0

* DAE (distillate aromatic extracts, DAE), distilled aromatic extracts

* TDAE (treated distillate aromatic extracts, TDAE),

Ca / Cp / Cn represents aromatic oils, paraffinic oils, and naphthene oils, respectively.

* Aniline point (℃) is a numerical value that indicates polarity, and measures the compatibility with aniline, which is a representative polar material, and becomes a management standard for workability and affinity with rubber.

Table 3. Composition of Comparative Example and Example (Unit: parts by weight)

division Comparative example Example Solution polymerization SBR # 1 40 - Solution polymerization SBR # 2 - 40 Emulsification Polymerization SBR 40 40 BR 20 20 DAE Oil 30 - TDAE Oil - 30 Silica 30 30 Silane coupling agent 4.8 4.8 Carbon black 45 45 Zincification 3 3 Stearic acid 3 3 Labor 4 4 Ok 2 2 sulfur 2.0 2.0 Vulcanization accelerator (NS) 1.9 1.9 Vulcanization accelerator (DPG) 0.6 0.6

<Test Example>

The rubber specimens prepared in Comparative Examples and Examples were measured for physical properties according to ASTM-related regulations, and the results are shown in Table 4 below.

Table 4. Physical Properties of Rubber Specimens of Comparative Examples and Examples

division Comparative example Example Hardness 68 70 300% Modulus (kg / cm ^ 2) 135 150 Rebound (%) 22 20 Dynamic viscoelasticity Glass transition temperature (Tg) (℃) -21 -18 0 ℃ Tangent Delta 0.353 0.383 70 ℃ Tangent Delta 0.175 0.161

* Tan δ (0 ℃): The value that can predict the wet traction characteristics of the wet state of the tire performance. The higher the value, the better.

* Tan δ (70 ℃): It is a value that can predict rolling resistance characteristics of tire performance. The lower the value, the better.

As seen in the results of Table 4 of the test example, high hardness values predict improved traction. A high 300% modulus value also predicts beneficial handling characteristics, while a low rebound indicates good grip characteristics on wet roads. In other words, when replacing only the process oil having a low PAH content in the existing rubber composition shows that the performance degradation can be improved by using a TDAE type process oil and some modification of the microstructure of the solution polymer.

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.

The tire tread rubber composition of the present invention uses a process oil containing a low polycyclic aromatic hydrocarbon compound (PAH) that satisfies environmental regulations as process oil, and controls the structure and composition of the raw material rubber, thereby lowering the polycyclic aromatic composition in the existing tire tread rubber composition. If only the process oil containing hydrocarbon compound (PAH) is replaced, the existing problem of deteriorating tire performance can be solved and the performance can be improved.

Claims (3)

In the tire tread rubber composition, Polycyclic aromatic to 100 parts by weight of raw material rubber consisting of 20 to 55 parts by weight of solution-polymerized styrene-butadiene rubber having a styrene content of 30 to 31% and a vinyl content of 31 to 36%, and 45 to 80 parts by weight of one or more rubbers. A tire tread rubber composition comprising 1 to 50 parts by weight of process oil having a hydrocarbon compound (PAH) content of less than 10 ppm and 30 to 40 parts by weight of any one or more fillers selected from calcium carbonate, clay and talc. delete A tire comprising a rubber comprising the rubber composition of claim 1.