KR101377399B1 - A rubber composite for tyre - Google Patents

Abstract

The present invention discloses a rubber composition for tire tread.
The rubber composition for tire treads according to the present invention is characterized in that it comprises raw material rubber and 40 to 70 parts by weight of modified nanosilica having a specific surface area of 200 m ² / g as a filler for 100 parts by weight of the raw material rubber. Accordingly, the rotational resistance characteristics can be improved while maintaining the braking characteristics by minimizing the energy loss generated as the deformation of the tire tread portion composite is repeated.

Description

Rubber composition for tire treads {A rubber composite for tyre}

The present invention relates to a rubber composition for a tire tread, and more particularly, a tire that minimizes energy loss caused by repeated deformation of a tire tread composite material, thereby maintaining a braking characteristic and improving a rolling resistance characteristic. It relates to a rubber composition for tread.

Conventionally, tires are characterized in their respective parts, such as sidewalls, treads, belts, beads, etc., depending on the required properties.

For treads that directly rub against double ground, wear, braking, and low rolling resistance (LRR) are key factors in tire design.

These properties are affected by the properties of the rubber material. Until the early 2000's, rubber compositions in which styrene-butadiene rubber prepared by emulsion polymerization method used as carbon black filler were mainly used.

Subsequently, a lot of research has been conducted when it is found that when silica is used as a filler instead of carbon black, rotational resistance and wet road braking characteristics can be improved, and raw rubber prepared by emulsion polymerization method has its fine structure ( In other words, it was difficult to control the styrene and butadiene structure, so it was not easy to achieve a certain performance.

This is because the wet road braking performance, rolling resistance characteristics, etc. of the tire change according to the microstructure of the raw material rubber.

However, the production of styrene butadiene rubber by the solution polymerization method has found a phenomenon that can control such a microstructure, and accordingly, the development of the polymerization raw material rubber is accelerated by the solution polymerization method. The application of silica and solution-polymerized styrene-butadiene rubber mentioned above can be said to improve the rolling resistance characteristics of tires.

Therefore, Korean Patent 2009-0055185 (KR 2009-0055185 A, Hankook Tire Co., Ltd., November 28, 2007) refers to a material to which a silica surface modified with polybutadiene is applied. This is to improve the rotational resistance characteristics by increasing the dispersion of the raw material rubber silica.

In this way, however, the glass transition temperature of the tread is reduced as a tire material, and thus the braking performance at low temperatures and the cracking performance at low temperatures can be reduced. Also, due to the polybutadiene coating, the reinforcement of silica is reduced and the physical properties of the tread are reduced. There was a problem of being reduced.

In addition, the Republic of Korea Patent 2005-00031702 (KR 2005-0031702 A, Kumho Tire Co., Ltd., September 30, 2003) is characterized in that the emulsified polymerization SBR rubber in which the raw material rubber end is modified with a basic functional group is applied. The brake braking performance and rolling resistance performance have been improved. However, it is difficult to freely change the vinyl group, which is the microstructure of the raw material rubber, in the emulsion polymerization, which is the polymerization method of the above technique, and this vinyl group content is a major factor for improving wet road braking characteristics and rolling resistance, which can be realized on tires. The technology was limited.

Therefore, the technical problem to be solved by the present invention is to minimize the energy loss caused by repeated deformation of the tire tread composite material while maintaining the braking characteristics, while improving the tire tread rubber composition To provide.

The present invention, in order to solve the above technical problem, characterized in that it comprises a raw material rubber and 40 to 70 parts by weight of modified nanosilica surface having a specific surface area of 200m ² / g as a filler for 100 parts by weight of the raw material rubber It provides a rubber composition for the tire tread.

According to an embodiment of the present invention, the raw material rubber has a styrene content of 25% and a vinyl content of 55% by weight of the solution-polymerized styrene-butadiene rubber 40 to 70 parts by weight of the hydroxyl group at the end of the hydroxyl group And, the styrene content of 41%, vinyl content of 18% of the emulsion polymerization styrene butadiene rubber may be composed of 10 to 60 parts by weight, butadiene rubber 5 to 15 parts by weight.

According to another embodiment of the present invention, the surface-modified nanosilica may have an average density of hydroxy functional groups of 7 to 9 OH groups / nm ² and an average size of particles of 150 to 250 nm.

According to the rubber composition for a tire tread according to the present invention, the rolling resistance characteristics can be improved while minimizing the energy loss caused by repeated deformation of the tire tread portion composite material.

These and other objects, features and other advantages of the present invention will become more apparent by describing in detail preferred embodiments of the present invention with reference to the accompanying drawings. Hereinafter, a rubber composition for a tire tread according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

The rubber composition for tire treads of the present invention is characterized in that it comprises raw material rubber and 40 to 70 parts by weight of modified nanosilica having a specific surface area of 200 m ² / g as a filler for 100 parts by weight of the raw material rubber.

The raw material rubber is a rubber used for tire tread, and may be used by mixing each or natural rubber or synthetic rubber.

In addition, the nano-silica is a surface having a specific surface area of 200m ² / g is modified, but may be used in the acid treatment or base treatment method, but within the range that can control the density of the hydroxy group (-OH) to be described later It is preferable to use.

On the other hand, the nano silica is used 40 to 70 parts by weight based on 100 parts by weight of the raw material rubber, if less than 40 parts by weight, Due to insufficient filling, the mechanical properties of the rubber composition may be reduced, and the handling performance of the tire may be reduced after manufacturing. This will happen.

In addition, other active agents, anti-aging agents, process oils, vulcanizing agents, vulcanization accelerators, etc. in order to secure physical properties such as wear, braking and low rolling resistance of the tire tread rubber composition in addition to the raw material rubber and the surface-modified nanosilica. Various additives can be used in a predetermined amount by appropriately selected as necessary, these are the general components used in the rubber composition for the conventional tire tread will be omitted in detail.

In addition, the raw material rubber is 30% to 70 parts by weight of a solution-polymerized styrene-butadiene rubber modified with a hydroxyl group of 25% styrene content, 55% vinyl content, and 100% by weight of the raw material rubber, styrene content 41%, 10 to 60 parts by weight of an emulsion-polymerized styrene-butadiene rubber having a vinyl content of 18% and 5 to 15 parts by weight of butadiene rubber. If the solution-polymerized styrene-butadiene rubber is less than 30 parts by weight, the effect of low rotational resistance is hardly affected. On the contrary, if it exceeds 70 parts by weight, an indirect indicator of manufacturing processability, 100 degrees C. Mooney viscosity is increased to 110 or more, which is accompanied by a disadvantage in process, and may cause a decrease in wet road surface braking performance.

In addition, if the emulsion-polymerized styrene-butadiene rubber is less than 10 parts by weight, wet road surface braking performance may decrease, on the contrary, if it exceeds 60 parts by weight, the low rolling resistance performance may decrease.

If the butadiene rubber is less than 5 parts by weight, the glass transition temperature may rise to cause a cold crack (cracking of tire treads at low temperature), and if it exceeds 15 parts by weight, wet grip performance on wet surfaces This can fall.

Meanwhile, the surface-modified nanosilica may have an average density of hydroxy functional groups of 7 to 9 OH groups / nm ² and an average size of particles of 150 to 250 nm, wherein the modified group of the raw material rubber (hydroxyl group ( -OH), carboxyl groups (-COOH), etc.) to secure a dispersing force, this interaction seems to be due to hydrogen bonding or intermolecular attraction, etc., if the average size is out of the range, clustering or dispersion This difficult problem can arise.

If the average density is less than 7, the bonding density with the raw material rubber or the coupling agent that induces chemical bonding becomes small, so that the viscosity of the compounding compound may increase, and the elongation and tensile strength may decrease. Excess hydroxyl groups cause viscosity to drop, which in turn leads to a drop in mechanical properties in the initial elongation range.

Although the preferred embodiment of the present invention is described above or next, the present invention is not limited to this specific embodiment. It will be apparent to those skilled in the art that numerous modifications and variations can be made in the present invention without departing from the spirit or scope of the appended claims. And equivalents should also be considered to be within the scope of the present invention.

<Examples 1 to 8>

10 to 60 parts by weight of SBR1739 (styrene 41 wt%, 18 wt% vinyl), an emulsion-polymerized styrene-butadiene rubber, and a solution-polymerized styrene butadiene rubber Asaprene Y031 (25 wt% of styrene, 55 wt% vinyl) with a hydroxyl group functional group 5 parts by weight of butadiene rubber (BR) as the raw material rubber, 50 parts by weight of silica (200MP) having a surface area of 200 m ² / g as a filler relative to 100 parts by weight of the raw material rubber, DBP value 114, CTAP value 10 parts by weight of this 96 carbon black (N375), 3 parts by weight of zinc oxide, 2 parts by weight of stearic acid, N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine as an antioxidant (brand name: 2 parts by weight of Kumanox-13) were placed in a Banbury mixer and blended to obtain a primary rubber compound. Next, 1.5 parts by weight of sulfur as a vulcanizing agent, 1.5 parts by weight of N-cyclohexyl-2-benzothiazole-sulfenamide (CZ) as a vulcanizing agent, and N, N- as a second vulcanizing accelerator were added to the rubber compound. 1.5 parts by weight of diphenylguanidine (DPG) was added to prepare a final rubber blend, which was quenched at 160 ° C. for 15 minutes to prepare a sample. Table 1 shows the rubber compositions of Examples 1 to 8.

<Examples 9 to 12>

30 parts by weight of SBR1739 (styrene 41 wt%, vinyl 18 wt%), an emulsion-polymerized styrene-butadiene rubber, 60 parts by weight of butapene Y031 (25 wt% of styrene, 55 wt% of vinyl) solution-polymerized styrene butadiene rubber 10 parts by weight of rubber (BR) as raw material rubber, 40 to 70 parts by weight of silica (200MP) having a surface area of 200 m ² / g as a filler with respect to 100 parts by weight of the raw material rubber, carbon having a DBP value of 114 and a CTAP value of 96 10 parts by weight of black (N375), 3 parts by weight of zinc oxide, 2 parts by weight of stearic acid, N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine (trade name: Kumanox-13) as an antioxidant 2 parts by weight were added to a Banbury mixer and blended to obtain a primary rubber blend. Next, 1.5 parts by weight of sulfur as a vulcanizing agent, 1.5 parts by weight of N-cyclohexyl-2-benzothiazole-sulfenamide (CZ) as a vulcanizing agent, and N, N- as a second vulcanizing accelerator were added to the rubber compound. Samples were prepared by adding 1.5 parts by weight of diphenylguanidine (DPG) to prepare a final rubber blend, which was vulcanized at 160 ° C. for 15 minutes. Tables 1 to 3 show the rubber compositions of Examples 9 to 12.

&Lt; Comparative Example 1 &

30 parts by weight of SBR1739 (styrene 41 wt%, vinyl 18 wt%), an emulsion-polymerized styrene-butadiene rubber, 60 parts by weight of solution-polymerized styrene butadiene rubber PBR4003 (contents of styrene 24 wt%, 41 wt% vinyl), and a butadiene rubber (BR) 10 parts by weight of raw material rubber, based on 100 parts by weight of the raw material rubber, 50 parts by weight of silica (Z115) having a surface area of 115 m ² / g as a filler, 10 parts by weight of carbon black (N375) having a DBP value of 114 and a CTAP value of 96 Parts, 3 parts by weight of zinc oxide, 2 parts by weight of stearic acid, 2 parts by weight of N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine (trade name: Kumanox-13) as an anti-aging agent to a Banbury mixer. It was added and blended to obtain a primary rubber compound. Next, 1.5 parts by weight of sulfur as a vulcanizing agent, 1.5 parts by weight of N-cyclohexyl-2-benzothiazole-sulfenamide (CZ) as a vulcanizing agent, and N, N- as a second vulcanizing accelerator were added to the rubber compound. 1.5 parts by weight of diphenylguanidine (DPG) was added to make a final rubber blend, which was vulcanized at 160 ° C. for 15 minutes to prepare a sample. Table 1 to 3 shows the rubber composition of Comparative Example 1.

&Lt; Comparative Example 2 &

30 parts by weight of SBR1739 (styrene 41 wt%, vinyl 18 wt%), an emulsion-polymerized styrene-butadiene rubber, 60 parts by weight of butadiene rubber (BR) 10 parts by weight of raw material rubber, 50 parts by weight of silica (200MP) having a surface area of 115 m ² / g as a filler relative to 100 parts by weight of the raw material rubber, 10 parts of carbon black (N375) having a DBP value of 114 and a CTAP value of 96 Parts, 3 parts by weight of zinc oxide, 2 parts by weight of stearic acid, 2 parts by weight of N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine (trade name: Kumanox-13) as an anti-aging agent to a Banbury mixer. It was added and blended to obtain a primary rubber compound. Next, 1.5 parts by weight of sulfur as a vulcanizing agent, 1.5 parts by weight of N-cyclohexyl-2-benzothiazole-sulfenamide (CZ) as a vulcanizing agent, and N, N- as a second vulcanizing accelerator were added to the rubber compound. 1.5 parts by weight of diphenylguanidine (DPG) was added to make a final rubber blend, which was vulcanized at 160 ° C. for 15 minutes to prepare a sample. Table 1 to 3 shows the rubber composition of Comparative Example 2.

division Comparative Example 1 Comparative Example 2 Example 1 Example 2 Example 3 Raw rubber (SBR1739 ^{1 )} ) 30 30 60 50 40 Raw rubber (PBR4003 ^{2 )} ) 60 60 0 0 0 Raw material rubber
(Asaprene Y031 ^{3 )} ) 0 0 35 45 55 Raw material rubber (BR01) 10 10 5 5 5 Silica 1 ⁴⁾ 50 50 0 0 0 Silica 2 ⁵⁾ 0 0 50 50 50 Carbon black 10 10 10 10 10 Zinc oxide 3 3 3 3 3 Stearic acid 2 2 2 2 2 Self-defense ^{6 )} 2 2 2 2 2 Vulcanizing (sulfur) 1.5 1.5 1.5 1.5 1.5 Vulcanization accelerator1 ^{7 )} 1.5 1.5 1.5 1.5 1.5 Vulcanization accelerator 2 ^{8 )} 1.5 1.5 1.5 1.5 1.5

division Example 4 Example 5 Example 6 Example 7 Example 8 Raw rubber (SBR1739 ^{1 )} ) 30 20 10 25 35 Raw rubber (PBR4003 ^{2 )} ) 0 0 0 0 0 Raw material rubber
(Asaprene Y031 ^{3 )} ) 60 70 70 60 60 Raw material rubber (BR01) 10 10 10 15 15 Silica 1 ⁴⁾ 0 0 0 0 0 Silica 2 ⁵⁾ 50 50 50 50 50 Carbon black 10 10 10 10 10 Zinc oxide 3 3 3 3 3 Stearic acid 2 2 2 2 2 Self-defense ^{6 )} 2 2 2 2 2 Vulcanizing (sulfur) 1.5 1.5 1.5 1.5 1.5 Vulcanization accelerator1 ^{7 )} 1.5 1.5 1.5 1.5 1.5 Vulcanization accelerator 2 ^{8 )} 1.5 1.5 1.5 1.5 1.5

division Example 9 Example 10 Example 11 Example 12 Raw rubber (SBR1739 ^{1 )} ) 30 30 30 30 Raw rubber (PBR4003 ^{2 )} ) 0 0 0 0 Raw material rubber
(Asaprene Y031 ^{3 )} ) 60 60 60 60 Raw material rubber (BR01) 10 10 10 10 Silica 1 ⁴⁾ 0 0 0 0 Silica 2 ⁵⁾ 40 45 60 70 Carbon black 10 10 10 10 Zinc oxide 3 3 3 3 Stearic acid 2 2 2 2 Self-defense ^{6 )} 2 2 2 2 Vulcanizing (sulfur) 1.5 1.5 1.5 1.5 Vulcanization accelerator1 ^{7 )} 1.5 1.5 1.5 1.5 Vulcanization accelerator 2 ^{8 )} 1.5 1.5 1.5 1.5

* Unit weight part *

1) SBR1739: 41 wt% styrene, 59 wt% butadiene, 18 wt% vinyl in butadiene

2) PBR4003: styrene 24wt%, butadiene 76wt%, butadiene vinyl 41wt%

3) Asaprene Y031: 25 wt% styrene, 75 wt% butadiene, 55 wt% vinyl in butadiene (terminal modified rubber)

4) Silica 1: silica having a surface area of 115 m ² / g

5) Silica 2: Silica showing a surface area of 200 m ² / g

6) Antioxidant: N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine (Kumanox-13)

Vulcanization Accelerator 1: N-cyclohexyl-2-benzothiazole-sulfenamide (CZ)

8) Vulcanization accelerator 2: N, N-diphenylguanidine (DPG)

<Test Example>

For each rubber specimen sample prepared in Examples 1 to 12 and Comparative Examples 1 to 2, 100 ° C Mooney viscosity, Shore A hardness, elongation (%), wet road surface braking performance index (tanδ @ 0) according to ASTM-related regulations. ℃), rotational resistance index (tan δ @ 70 ℃), the wear characteristics were measured and the results are shown in Tables 4 to 6 below.

division Comparative Example 1 Comparative Example 2 Example 1 Example 2 Example 3 Mooney viscosity 88 92 81 87 89 Hardness 60 67 62 63 65 Elongation (%) 445 420 489 476 452 tanδ @ 0 ℃ 0.452 0.448 0.522 0.529 0.541 tanδ @ 70 ℃ 0.119 0.124 0.113 0.098 0.095

division Example 4 Example 5 Example 6 Example 7 Example 8 Mooney viscosity 74 73 75 72 72 Hardness 67 67 67 67 67 Elongation (%) 457 418 421 429 445 tanδ @ 0 ℃ 0.554 0.548 0.543 0.494 0.483 tanδ @ 70 ℃ 0.091 0.090 0.094 0.087 0.088

division Example 9 Example 10 Example 11 Example 12 Mooney viscosity 65 71 83 91 Hardness 61 64 72 76 Elongation (%) 445 463 431 405 tanδ @ 0 ℃ 0.562 0.554 0.548 0.521 tanδ @ 70 ℃ 0.092 0.094 0.103 0.128

 Mooney viscosity is measured at 100 ℃, the lower the better flowability, the higher the flowability is disadvantageous in terms of extrusion process.

* Hardness is Shore A hardness standard, the value of 100 means the hardness of the glass (Glass), the higher the value can be said that the tire steering performance is better, but at the level of 75 or more has a characteristic of less stability (Ride).

* The elongation is a percentage value indicating how much the tensile strength in the longitudinal direction is increased compared to the initial sample length. The higher the tensile strength is, the better the fatigue characteristics (destructive characteristics) are. There is no level. However, if it is lower than 400, there may be quality problems such as chunking in the field.

* 0 ° C tanδ is measured by GABO tester and 11Hz. Used as an index of wet road braking performance, the higher the value, the better the wet road braking performance.

* 70 ℃ tanδ is measured by GABO tester and is measured by 11Hz. It is used as an index of rotational resistance performance, and the lower the value, the better the rotational resistance performance.)

As can be seen in Tables 4 to 6, the rubber composition for the tire tread according to the present invention has excellent wet road surface braking performance (0 ° C tanδ) and rotational resistance (70 ° C tanδ), and the rolling resistance is improved. As the hardness increases, the steering performance (Handling) is excellent.

Claims (3)

Raw material rubber and 40 to 70 parts by weight of the surface-modified nanosilica having a specific surface area of 200 m ² / g as a filler for 100 parts by weight of the raw material rubber,
The surface-modified nanosilica is a tire tread rubber composition, characterized in that the average density of hydroxy functional groups is 7 to 9 OH groups / nm ² and the average size of the particles 150 to 250 nm. The method of claim 1,
The raw rubber is 30 to 70 parts by weight of a solution-polymerized styrene-butadiene rubber modified with a hydroxyl group of 25% styrene content, 55% vinyl content, and 100% by weight of the raw material rubber, styrene content 41%, vinyl content A tire tread rubber composition comprising 10 to 60 parts by weight of this 18% emulsion-polymerized styrenebutadiene rubber and 5 to 15 parts by weight of butadiene rubber.
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