KR100437687B1 - Dispersion-Improved Silica-filled SBR compounds Containing NSBR for Tire - Google Patents

Abstract

The present invention relates to a SBR rubber composition for tires reinforced with silica.

The rubber composition of the present invention improves the dispersibility of silica by adding an appropriate amount of NSBR (acrylonitrile-styrene-butadiene rubber), a polymer having a polar functional group, to improve silica dispersibility, and improves the dispersibility of silica and is adsorbed on the silica surface. Since the amount of the agent can be significantly reduced, there is an effect of improving the overall physical properties such as tensile properties and wear characteristics.

Description

SBR rubber composition for tires reinforced with silica with improved dispersibility by adding NSR {Dispersion-Improved Silica-filled SBR compounds Containing NSBR for Tire}

The present invention relates to an SBR rubber composition for tires reinforced with silica. More specifically, in order to improve dispersibility of silica, a rubber in which an appropriate amount of NSBR (acrylonitrile-styrene-butadiene rubber), a polymer having a polar functional group, is added as a raw material rubber It relates to a composition.

Silica, along with carbon black, is a popular reinforcement in the tire industry. Unlike carbon black, silica has a large amount of silanol (Si-OH) on its surface and has a strong polarity. Natural rubber (NR), styrene-butadiene rubber (SBR) and butadiene rubber (BR), which are commonly used in the tire industry, are very weak polar polymers and have low affinity with silica. There is a characteristic that is not easy.

In order to improve the dispersion of silica in rubber, a silane coupling agent is used to introduce a weakly polar functional group on the silica surface or to improve affinity with rubber and to induce chemical bonding between silica and rubber. Since surface-treated silica is expensive, it is more common to add a silane coupling agent to ordinary silica rather than to use surface-treated silica. Representative silane coupling agents currently in use include bis- (3- (triethoxysilyl) -propyl) -tetrasulfide (TESPT), known under the trade name Si69.

However, it was difficult to expect a satisfactory effect on the dispersibility of silica only by the conventional method of adding the silane coupling agent or dispersant as described above. Therefore, the exploration of new ways to improve the dispersibility of silica and improve the overall physical properties and processability of the vulcanizate is a very important factor in the future tire industry.

The present inventors came to complete the present invention by discovering that adding proper amount of NSBR to the raw material rubber can improve all of the above characteristics while devising a method for overcoming the limitations of the prior art. .

Accordingly, an object of the present invention is to improve the dispersibility of silica and to significantly reduce the amount of vulcanizing agent adsorbed on the surface of silica, thereby providing a novel SBR rubber composition for tires which can improve various physical properties such as tensile properties and wear characteristics. Is in.

The present invention includes a rubber composition to which a suitable SBR rubber composition for tires reinforced with silica is added NSBR, a polymer having a polar functional group, in order to improve the dispersibility of silica. In this case, the rubber composition includes the SBR rubber composition in which the reinforced silica contains 10 to 90 phr in the rubber composition.

As described above, NSBR is a polymer composed of acrylonitrile, styrene and butadiene, among which acrylonitrile includes a nitrile group (-C≡N) having a relatively strong polarity. The nitrile group forms a hydrogen bond with the hydroxyl group (-OH) on the silica surface and thus exists on the silica surface to prevent agglomeration of the silica and thereby improve the dispersibility of the silica in the rubber compound.

In addition, since NSBR added in the rubber compound is similar in structure to SBR, NSBR present on the silica surface can be easily mixed with SBR.

The amount of NSBR added in the rubber compound is not particularly limited, but may be added in an amount of 20 phr or less relative to the raw material rubber in order to implement a more preferred embodiment.

When applying the appropriate amount of NSBR to the SBR rubber compound as described above, as well as improving the dispersibility of the silica and the amount of vulcanizing agent adsorbed on the surface of the silica can be significantly reduced to improve the overall physical properties such as tensile properties and wear characteristics do.

The present invention also includes an automobile tire comprising the SBR rubber composition containing the NSBR. Since the manufacturing process of the tire is generally manufactured by an example of a known method, a detailed description thereof will be omitted.

Hereinafter, the contents of the present invention will be described in detail with reference to the following examples, but the scope of the present invention is not limited to these examples.

Comparative Example 1 Preparation of Rubber Specimen

As shown in Table 1, SBR 1500 (styrene content: 37.5%), which is emulsion SBR, is 100phr, and silica 50.0phr, TESPT 3.0phr, stearic acid 2.0phr, zinc oxide 4.0phr, and HPPD 2.0 as an antioxidant phr, 2.0 phr wax, 1.4 phr of TBBS (N-tert-butyl-2-benzothiazole sulfenamide), 1.0 phr of DPG (diphenylguanidine) and 1.2 phr of sulfur were vulcanized at 160 ° C. for 20 minutes to obtain a rubber specimen. .

Example 1 Preparation of Rubber Specimen 2

As shown in Table 1, 100 phr of raw rubber composed of 95 phr of SBR 1500 (styrene content: 37.5%) and NSBR 5.0 phr, silica 50.0 phr of raw rubber, TESPT 3.0 phr, stearic acid 2.0 phr, zinc oxide 4.0 phr, HPPD 2.0 phr, wax 2.0 phr, anti-aging agent, TBBS 1.4 phr, DPG 1.0 phr, sulfur 1.2 phr was blended at 160 ° C. for 20 minutes to obtain a rubber specimen.

Example 2 Preparation of Rubber Specimen 3

As shown in Table 1, 100 phr of raw rubber composed of 85 phr of SBR 1500 (styrene content: 37.5%) and NSBR 15.0 phr, silica 50.0 phr of raw rubber, TESPT 3.0 phr, stearic acid 2.0 phr, zinc oxide 4.0 phr, HPPD 2.0 phr, wax 2.0 phr, anti-aging agent, TBBS 1.4 phr, DPG 1.0 phr, sulfur 1.2 phr was blended at 160 ° C. for 20 minutes to obtain a rubber specimen.

<Table 1> Compounded rubber composition (unit: phr)

Kinds Comparative example Example 1 Example 2 SBR 1500 100.0 95.0 85.0 NSBR 0.0 5.0 15.0 Silica 50.0 50.0 50.0 TESPT (Si69) 3.0 3.0 3.0 Stearic acid 2.0 2.0 2.0 Zinc oxide 4.0 4.0 4.0 HPPD 2.0 2.0 2.0 Wax 2.0 2.0 2.0 TBBS 1.4 1.4 1.4 sulfur 1.2 1.2 1.2 DPG 1.0 1.0 1.0

<Test Example 1>

Experimental results of measuring the pattern viscosity, the vulcanization time, and the delta torque of the rubber specimens according to the test examples and examples according to a known method are shown in Table 2 below.

<Table 2> Measurement result of pattern viscosity, vulcanization time and delta torque

Formulation Type Comparative example Example 1 Example 2 ML 1 + 4 (100 ° C) 98.0 95.0 94.0 Proper Curing Time (min) 11.72 10.61 10.47 Delta torque (Nm) 3.4 3.9 3.8

As can be seen from the results of Table 2, it can be seen that the viscosity of the formulation is lowered when applying NSBR. The scorch time is almost unchanged, and the optimum holding time is faster with NSBR.

On the other hand, the delta torque represents the difference between the minimum torque and the maximum torque in the rheograph. When the delta torque is large, the crosslinking density increases. The addition of NSBR in Table 2 increases the delta torque. From this, it was found that the addition of NSBR prevents the vulcanizing agent from adsorbing onto the silica surface, thereby increasing the crosslinking density.

<Test Example 2>

Experimental results of measuring the physical properties of the rubber specimens according to the test examples and examples according to a known method are shown in Table 3 below.

<Table 3> Measurement Results of Rubber Specimen

Kind of vulcanizate Comparative example Example 1 Example 2 ShoreA 65.0 66.0 68.0 300% modulus (kg / ㎠) 83.7 91.2 101.3 Tensile Strength (kg / ㎠) 232.0 245.8 248.4 Elongation at break (%) 582.1 578.5 556.4

According to Table 3, the hardness, modulus, tensile strength, etc. of the vulcanizate added with NSBR were increased and the elongation was slightly decreased. This difference in physical properties is due to the increase in the crosslinking density by improving the dispersibility of the silica and preventing adsorption of the vulcanizing agent.

The SBR rubber compound according to the present invention can improve the dispersibility of silica added as a reinforcing agent and can significantly reduce the amount of vulcanizing agent adsorbed on the silica surface, thereby improving the overall physical properties such as tensile properties and wear characteristics.

Claims (4)

In the SBR rubber composition for tires reinforced with silica, SBR rubber composition for tires, characterized in that 10 to 90 phr of silica with respect to 100 phr of raw rubber including NSBR to improve the dispersibility of silica. The SBR rubber composition for a tire according to claim 1, wherein NSBR is added in an amount of 5 to 20 phr in the raw material rubber. delete delete