KR20030012103A - Process for preparing silica reinforced tread rubber composition - Google Patents

Abstract

PURPOSE: Provided is a method of preparing a rubber composition for a tire thread. The method simplifies the mixing process, shortens the mixing time, and enhances the crosslinking property. CONSTITUTION: The preparation method comprises the following steps of: making wet master batch by mixing rubber, wet silica and silane coupling agent, wherein the rubber is SBR-1500 and 40-80wt.%(based on 100wt.% of rubber) of wet precipitated silica is used, the silica having a surface area of 100-200m2/g by BET and dibutylphthalate(DBP) absorbency value of 150-300ml/100g; and finally adding and mixing additives. In the process, the wet silica is not dried after milling granular process and is prepared through a process of condensation and drying is applied after silane coupling agent and rubber are mixed.

Description

Process for producing rubber composition reinforced with silica {PROCESS FOR PREPARING SILICA REINFORCED TREAD RUBBER COMPOSITION}

The present invention relates to a method for producing a rubber tread rubber composition, characterized in that first preparing a silica wet masterbatch, and then blending an additive thereto.

In order to reduce the rolling resistance of the tire as part of the low fuel consumption of the conventional vehicle, technologies that use silica instead of carbon black, which occupies a large proportion in the tire tread rubber composition, have been continuously developed.

However, since silica is composed of polar silanol groups, silica is mainly used for tire treads such as natural rubber (NR), styrene-butadiene rubber (SBR) or butadiene rubber (BR). There is a problem that the reaction is weak.

In addition, since the silanol groups are strongly bonded by hydrogen bonds, they do not easily disperse. Since the silica structure is not easily dispersed during the compounding process, there is a problem in that a stronger shear force is applied or a compounding process must be added.

In addition, there is a problem that a large amount of compounding time is required in order to sufficiently react the coupling agent with the silica.

The present invention is to provide a method for producing a rubber tread rubber composition, characterized in that the silica wet masterbatch is first manufactured in order to improve the inefficiency in the compounding process of the conventional silica rubber composition as described above. For that purpose.

The method for producing a rubber composition of the present invention is characterized by first preparing a silica wet masterbatch.

The silica wet masterbatch used in the present invention may be obtained by mixing wet silica and a silane coupling agent with rubber, followed by coagulation and drying.

The rubber used in the present invention may include, for example, a single diene-based rubber single component such as natural rubber (NR), styrene butadiene rubber (SBR) or butadiene rubber (BR), or a blend thereof. In particular, the rubber component is preferably SBR-1500.

In addition, the silica used in the present invention can be used as long as it is used in a conventional silica-rubber composition, preferably the specific surface area measured using BET is 100 ~ 200m ² / g, dibutyl phthalate (DBP) Precipitated silica having an adsorption value of 150 to 300 ml / 100 g is suitable, and the amount thereof is preferably 40 to 80 parts by weight based on 100 parts by weight of the rubber component. In addition, the wet silica used in the present invention is milled granulation in a process of drying after filtration, drying, milling granulation after precipitation, which is a conventional silica manufacturing process, and then drying again. It means the thing which did not go through the after-drying process.

In addition, the silane coupling agent used in the present invention may be selected and used a conventional silane crosslinking agent, for example, TESPT (bis- (3-triethoxysilylpropyl) tetrasulfane) is preferred. It is preferably included in 4 to 14% by weight, more preferably in about 8% by weight.

Hereinafter, the present invention will be described in detail through examples. However, the following examples are for illustrative purposes only and the present invention is not limited thereto.

Example

The rubber composition was prepared under the conditions of the compounding process shown in Table 2 with the composition shown in Table 1, and then a specimen for measuring physical properties was prepared. After vulcanizing the specimen, the physical properties were measured according to the ASTM standard method, and the results are shown in Table 3 together.

In the compounding process of Table 2, step 1 is a compounding step of SBR-1500, silica and TESPT. However, in the case of Example 1, since the wet masterbatch in which these components were already mix | blended was used, it showed blank. Step 2 is a compounding step by adding zinc and stearic acid to the rubber composition blended in step 1. Step 3 is a step of adding sulfur, N-cyclohexyl-2-benzothiazol sulfenamide (CZ) and DPG (N, N-diphenylguanidine) to the rubber composition blended in step 2.

Comparative example

In this comparative example, a rubber composition was prepared by directly mixing rubber (SBR-1500), silica, and a coupling agent (TESPT) according to a conventional method.

Example 1

This example is to prepare a rubber composition by first preparing a wet master batch containing the same amount of rubber (SBR-1500), wet silica, and coupling agent (TESPT), and then other additives.

Table 1. Rubber composition

Composition (part by weight) Comparative example Example Silica M / B 0 175.6 SBR-1500 100 0 Silica 70 0 TESPT * 5.6 0 Zinc (ZNO-S) 4 4 Stearic acid 2 2 sulfur 1.5 1.5 CZ ** 1.5 1.5 DPG *** 1.5 1.5

* TESPT: bis- (3-triethoxysilylpropyl) tetrasulfane (silane coupling agent)

** CZ: N-cyclohexyl-2-benzothiazol sulfenamide (primary accelerator)

*** DPG: N, N-diphenylguanidine (secondary promoter)

Table 2. Condition of compounding process

Compounding stage Dump temperature (compound time) of the comparative example Dump temperature (compound time) of Example 1 Step 1 150 ° C (4 minutes) * Step 2 150 ° C (4 minutes) 160 ° C (5 minutes) Step 3 100 ° C (2 minutes) 100 ° C (2 minutes)

* Uses a wet masterbatch already formulated with SBR-1500, silica and TESPT.

Table 3. Properties of Rubber Composition

Properties Comparative example Example 1. Mooney test @ 125 ℃ viscosity 80 90 2. Tensile Properties Hardness 300% Modulus (kgf / cm ² ) Tensile Strength (kg / cm ² ) Elongation (%) 75130220450 75140270520 3. Dynamic Characteristics TAN δ0 ℃ TAN δ70 ℃ 0.3440.153 0.3770.143 4. Wear characteristics pico loss (g) 0.031 0.021

As can be seen in Table 3, the rubber composition according to the embodiment of the present invention is improved in tensile properties such as 300% modulus, tensile strength, elongation while maintaining the same level of hardness compared to the rubber composition of the comparative example, The handling performance (the higher the value of TAN δ0 ℃) is excellent, the better the rolling resistance (the better the value of TAN δ70 ℃ is lower), and the better abrasion resistance (the smaller the pico loss value is).

According to the invention, the steps of the compounding process are reduced, thereby shortening the compounding time and improving the physical properties of the vulcanizate.

Claims (4)

In the method for producing a silica-reinforced rubber composition comprising a mixture of silica, a silane coupling agent and an additive to a raw rubber, a silica wet masterbatch in which rubber, wet silica and a silane coupling agent are mixed is prepared. After the preparation, a method for producing a silica-reinforced rubber composition, characterized in that an additive is added thereto. The method of claim 1, wherein the wet silica is a silica-reinforced rubber composition according to claim 1, wherein the silica is not dried after the milling granulation process in a conventional silica manufacturing process. The method of claim 1, wherein the wet masterbatch is manufactured by mixing wet silica and a silane coupling agent with rubber, and then performing a flocculation and drying process. The precipitated silica according to claim 1, wherein the silica is a precipitated silica having a specific surface area of 100 to 200 m ² / g and a dibutyl phthalate (DBP) adsorption value of 150 to 300 ml / 100 g as measured using BET. 40 to 80 parts by weight, and the rubber is SBR-1500, and the silane coupling agent is TESPT.