KR100715718B1 - Pcr tread compound for pneumatic tire - Google Patents

Abstract

The present invention is composed of a solution-polymerized styrene butadiene rubber 50 ~ 70 phr, the glass transition temperature is -35 ~ -30 ℃, a solution polymerization styrene butadiene rubber 10 ~ 30 phr, the glass transition temperature is -26 ~-22 ℃, butadiene rubber 20 ~ 40 phr It relates to a rubber composition for tire treads containing 35 to 55 phr of carbon black and 30 to 50 phr of silica with respect to 100 phr of raw rubber.

The tire tread rubber composition according to the present invention does not deteriorate abrasion resistance while improving braking force and fuel economy performance.

Tire tread rubber composition, braking force, fuel economy performance, wear resistance performance, silica

Description

Pneumatic tire tread rubber composition for passenger car {PCR TREAD COMPOUND FOR PNEUMATIC TIRE}

The present invention relates to a rubber tread rubber composition excellent in fuel efficiency and braking power without compromising wear resistance.

The properties of tire tread rubber are so diverse that it is necessary to have all the characteristics such as steering stability, noise, straightness, rolling resistance, braking force, abrasion resistance, and durability, so as to closely correspond to the driver's adjustment force under any conditions.

However, among the above characteristics, there is a high possibility that other operations may be deteriorated due to the adverse effect of the operation to improve specific properties. There was a technical difficulty in its development because it meant that only the desired properties had to be improved without receiving them.

Recently, since environmental issues have become the most important factor in the automotive industry, efforts have been made to reduce fuel consumption by reducing rolling resistance as much as possible. When carbon black is used in place of silica in order to reduce rolling resistance and reduce fuel efficiency, fuel efficiency is improved, but there is a problem in that the wear resistance is inferior because it adversely affects the wear performance. In addition, there are still problems such as the need to add other additives in order to increase the affinity with the polymer by using silica to increase fuel efficiency, or cost increase when selecting a polymer having special physical properties. Therefore, when carbon black is replaced with some silica, there has been a demand for a rubber tread rubber composition having excellent fuel efficiency without deteriorating abrasion performance without adjusting an additive such as adding a rubber component.

The tread rubber composition for a tire of the present invention is to solve such a problem, and to provide a rubber tread rubber composition having excellent fuel efficiency without degrading abrasion resistance by adjusting the composition of the rubber component.

The present invention is 50 to 70 phr of solution-polymerized styrene-butadiene rubber having a glass transition temperature of -35 to -30 ° C, 10 to 30 phr of solution-polymerized styrene butadiene rubber having a glass transition temperature of -26 to -22 ° C, and 20 to 40 phr of butadiene rubber. With respect to 100 phr of the raw rubber, the rubber composition for tire treads including 35 to 55 phr of carbon black and 30 to 50 phr of silica is provided.

 In the present invention, two kinds of solution-polymerized styrene-butadiene rubbers having a glass transition temperature (Tg) of -35 to -30 ° C and -26 to -22 ° C, respectively, are used as components of the raw material rubber.

The amount of the solution-polymerized styrene-butadiene rubber having a glass transition temperature of -35 to 30 ° C. is 50 to 70 phr, and if the content is less than 50 phr, wear resistance and snow resistance are lowered. not.

In addition, the amount of the solution-polymerized styrene-butadiene rubber having a glass transition temperature of -26 ~ -22 ℃ is 10 ~ 30phr, when the content is less than 10phr, the handling performance is lowered, if it exceeds 30phr it is not preferable because the fuel efficiency and wear resistance decreases.

The solution-polymerized styrene-butadiene rubber having a glass transition temperature of -35 to -30 ° C and the solution-polymerized styrene-butadiene rubber having a glass transition temperature of -26 to -22 ° C are not particularly limited as long as the glass transition temperature is in the above range. Commercially available products include SOLFLEX-2535X (brand name, styrene content 25% by weight, vinyl content 35% by weight, Tg -32 ℃, Goodyear USA) and SE SLR-4601 (brand name, styrene content 21%). %, Vinyl content 63 weight%, Tg-24.5 degreeC, the Dow Corporation of America) is mentioned.

In the present invention, butadiene rubber is used as the raw material rubber component in addition to the two kinds of solution-polymerized styrene butadiene rubbers. As butadiene rubber used for this invention, it is preferable to use butadiene rubber with high cis content especially. It is preferable that the cis content of butadiene rubber is 98 weight% or more. If the sheath content of butadiene rubber is less than 98% by weight, there is a fear that the wear resistance is lowered. The butadiene rubber which can be used in the present invention is not particularly limited as long as it has a high cis content, and commercially available products include Nd-BR (trade name, cis content 98 wt%, nitrile content 10 wt%, and Tg -105 ° C). Bayer company) is mentioned.

In the rubber composition of the present invention, when the butadiene rubber is contained in less than 20 phr, the wear resistance is insufficient. When the rubber composition contains more than 40 phr, the wear resistance is greatly improved, but the braking force and the like deteriorate.

Carbon black used as a reinforcing material in the present invention is not particularly limited in its grade, the amount is preferably in the range of 35 ~ 55phr. If the content of carbon black is less than 35 phr, mechanical properties such as wear resistance and rigidity may be lowered. If the content of carbon black is more than 55 phr, rotational resistance may be increased and fuel efficiency may be increased, which is not preferable.

  Silica used in combination with the carbon black in the present invention is not particularly limited in its kind, the amount is preferably in the range of 30 ~ 50phr. If the content of silica is less than 30 phr, the fuel efficiency improvement effect is insufficient. If the content of silica is more than 50 phr, the wear resistance is lowered.

In addition to the above-mentioned components, the rubber composition of the present invention may be used additives, which are commonly used in rubber tread rubber compositions, for example, additives such as softeners, activators, lubricating agents, vulcanizing agents, accelerators, etc. in the usual usage ranges. .

Hereinafter, the present invention will be described in more detail with reference to Examples. However, these examples do not limit the scope of the present invention.

Examples and Comparative Examples

A rubber composition was prepared according to the composition of Table 1, and the physical properties thereof were tested and shown in Table 1.

According to ASTM D113184-80, a carbon black master batch was prepared by blending each raw material except the vulcanizing agent and the accelerator at 40 rpm in a capacity 1.6 L sealed mixer (BR LAB BANBURY MIXER, FARREL CO.), A vulcanizing agent and a promoter were added and final blended at 30 rpm for 60 seconds. This blended rubber was vulcanized at 160 ° C. for 20 minutes to prepare a specimen. Tensile properties were measured at room temperature using a tensile tester (INSTRON 6012) according to ASTM D-412.

Table 1 Mixing ratio of rubber composition and its physical properties (unit: phr)

division Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Rubber SOLFLEX-2535X ¹⁾ 50 (68.5 including oil) SE-SLR-4601 ²⁾ 30 20 10 50 40 0 Nd-BR ³⁾ 20 30 40 0 10 50 Softener Oil ⁴⁾ 5.00 5.00 5.00 7.00 3.00 5.00 Active agent ZnO # S 3.00 3.00 3.00 3.00 3.00 3.00 Carbon black N-375 40 40 40 75 40 40 Silica z-175 40 40 40 - 40 40 Labor K-RD ⁵⁾ 2.00 2.00 2.00 2.00 2.00 2.00 K-13 ⁶⁾ 2.00 2.00 2.00 2.00 2.00 2.00 Sunnoc ⁷⁾ 2.00 2.00 2.00 2.00 2.00 2.00 Active agent S / A 2.00 2.00 2.00 2.00 2.00 2.00 Vulcanizing agent sulfur 2.00 2.00 2.00 2.00 2.00 2.00 accelerant CZ ⁸⁾ 1.80 1.80 1.80 1.80 1.80 1.80 DPG (vulcanization accelerator) ⁹⁾ 0.45 0.45 0.45 0.45 0.45 0.45  Toughness (Initial) Hardness 71 69 69 65 72 65 300% modulus (㎏ / ㎠) 137 133 113 103 138 110 Tensile Strength (㎏ / ㎠) 201 217 208 202 218 215 % Elongation 458 437 445 490 451 510  Dynamic tensile properties Tg (0 ° C) -21 -26 -30 -11 -16 -35 Tanδ (0 ° C) ¹⁰⁾ 0.319 0.302 0.250 0.212 0.339 0.223 Tanδ (70 ° C) ¹¹⁾ 0.101 0.090 0.089 0.165 0.095 0.090 rebound 1st 17.4 20.1 20.4 12.12 16.4 21.3 Wear resistance PICO (g) ¹²⁾ 0.035 0.029 0.029 0.030 0.038 0.028

^{Note 1)} SOLFLEX-2535X: solution polymerization-SBR; Styrene 25% by weight, vinyl 35% by weight, glass transition temperature -32 ℃, manufactured by Goodyear USA

^{Note 2)} SE SLR-4601: solution polymerization-SBR; 21 wt% styrene, 63 wt% vinyl, glass transition temperature -24.5 ° C, manufactured by Dow, USA

^{Note 3)} Nd-BR Rubber: Sheath 98% by weight, nitrile 10% by weight, glass transition temperature -105 ℃, Bayer,

^{Note 4)} Oil: aromatic oil

^{Note 5)} K-RD: 2,2,4-trimethyl-1,2-dihydroquinoline, manufactured by Kumho Petrochemical Co., Ltd.

^{Note 6)} K-13 is manufactured by Flexis.

^{Note 7)} Sunnoc: Hydrocarbon Wax, Yongjin Oil

^{Note 8)} CZ: N-cyclohexyl-2-benzothiazole sulfenamide, manufactured by Dongyang Steel Chemical Co., Ltd.

^{Note 9)} DPG: 1,3-diphenylguanidine, manufactured by Kumho Petrochemical Co., Ltd.

^{Note 10)} Tanδ (0 ℃): The higher the value, the better the braking force.

^{Note 11)} Tanδ (70 ℃): The lower the value, the lower the rolling resistance.

^{Note 12)} PICO (g): As a result of the abrasion test, the degree of wear is expressed in grams. The smaller the value, the better the wear resistance.

As can be seen from the results of Table 1, in comparison with Comparative Example 1 in which no butadiene rubber having high silica and cis content is used, Examples 1 to 3 of the present invention do not deteriorate abrasion resistance and brake performance and fuel efficiency. It can be seen that the remarkable improvement.

In addition, although both of the two types of solution-polymerized styrene-butadiene rubber was used, compared to Comparative Example 2, the content of which is outside the scope of the present invention, Examples 1 to 3 of the present invention can be confirmed that the wear resistance is better, Compared to the rubber composition of Comparative Example 3 using only one kind of solution-polymerized styrene butadiene rubber, it can be confirmed that the rubber composition of Examples 1 to 3 of the present invention was improved while maintaining the wear resistance at an equivalent level. .

The tire tread rubber composition according to the present invention does not deteriorate abrasion resistance while improving braking force and fuel efficiency.

Claims (2)

100phr of raw material rubber consisting of solution-polymerized styrene-butadiene rubber with glass transition temperature of -35 ~ -30 ℃, 10 ~ 30phr of solution-polymerized styrenebutadiene rubber with glass transition temperature of -26 ~ -22 ℃, and 20 ~ 40phr of butadiene rubber About, the rubber composition for tire treads containing 35-55 phr of carbon black and 30-50 phr of silica. The rubber composition for tire treads according to claim 1, wherein the butadiene rubber has a sheath content of 98% by weight or more.