KR100856732B1 - A rubber composition for tire and a method for manufacturing the same - Google Patents

Abstract

The present invention relates to a rubber composition for a silica mixed tire and a manufacturing method thereof.

In a rubber composition and a manufacturing method, which is prepared through a series of steps of mixing a silica or silica slurry with a silane coupling agent, a surfactant, a vulcanization accelerator, a process oil and a coagulant on a rubber latex, and then solidifying and drying them together.

_{-S 2 - (CH 2) 6} -S 2 - as by previously mixing a silane coupling agent (A) of the structure and Aro matic made five days in the emulsion, and then the roughness characterizing step of mixing with the rubber latex in the stable state,

It is possible to obtain a silica rubber composition for a tire having significantly superior physical properties compared to a silica rubber composition prepared by mixing a conventional silane coupling agent, ie, TESPT on rubber latex without pretreatment.

Rubber latex, silica, silane coupling agent, tires.

Description

Rubber composition for a tire and its manufacturing method {a rubber composition for tire and a method for manufacturing the same}

The present invention relates to a rubber composition for a tire and a method of manufacturing the same, and more particularly, to significantly improve scorch generation during a mixing process or a drying process due to a silane coupling agent of -S ₄ -polysulfide structure and a resultant tire quality defect. It is invention which concerns on the rubber composition for tires which can be made, and its manufacturing method.

Traditionally, carbon black has been used as a filler to reinforce the mechanical properties of rubber.

Since the 1990s, silica has begun to be mixed with some carbon black to improve tire braking, steering stability and reduce fuel consumption.

Tires manufactured using a silica-mixed master batch improve the dynamic viscoelastic properties at low and high temperatures, resulting in lower fuel consumption due to increased braking performance on wet roads and improved rolling resistance. There is this.

This is because the interaction between the fillers of silica is stronger than that of carbon black.

As a mixing method of silica, the dry mixing method of melt | dissolving a solid rubber using a short-barrier mixer, then adding a silica, a silane coupling agent, a vulcanization accelerator, and other rubber additives, and forcibly mixing is mentioned.

According to the dry silica mixing method as described above, the cost of the production process increases due to the adsorption of silica and the like of the vulcanization accelerator, and the mixing time is increased.

In addition, when more silica is mixed for the purpose of improving braking performance and fuel efficiency, the dispersibility is sharply lowered due to the surface characteristics of the hydrophilic silica, which causes a problem that the wear resistance of the tire is lowered.

In order to supplement the problems with the dry mixing method, a manufacturing method (wet mixing master batch) has been developed in which fillers are mixed on rubber latex and then solidified together.

The wet mixing method of mixing carbon black as a filler on rubber latex, then solidifying and drying, has been used in the rubber industry since the 1970s.

As a method of drying after solidification, there may be various methods such as using a roll mill or an extruder at room temperature or high temperature.However, on US Patent No. 6,040,364, a method of continuously manufacturing carbon black wet master batches by using an extruder is described. .

On the other hand, in order to increase the amount of silica mixed as another filler and at the same time to improve the wear resistance of the tire and to stabilize the production process, the silica is mixed on a rubber latex and then coagulated together (silica wet mixing master batch ( silica wet mixing master batch) has recently been developed.

The method of preparing a rubber composition using the silica wet mixed master batch is different in that silica is used instead of carbon black, but is essentially the same in terms of dispersing the filler on rubber latex and then solidifying them together.

The rubber composition using a silica mixing master batch by the silica wet mixing method is a mixture of silica or silica slurry with a silane coupling agent, a surfactant, a vulcanization accelerator, a process oil and a coagulant on a rubber latex, and then solidify them together. It is manufactured by drying.

As mentioned above, in the preparation of silica wet mixed master batches, the mixing and drying of surfactants, vulcanization accelerators, process oils, coagulants and the like except for silane coupling agents are the same as those of the carbon black wet mixed master batches. You can understand it as a concept.

The silane coupling agent has long been used to interconnect hydrophilic silica and hydrophobic rubber.

Currently, TESPT (Bis (triethoxysilylpropyl) tetrasulfan) is mainly used as a silane coupling agent in the rubber manufacturing process for tires, and the molecular formula thereof is as follows.

The TESPT has a polysulfide structure of -S _4- , and has a low dissociation energy.

Low dissociation energy may cause crosslinking as sulfur (S) is liberated during the mixing process prior to the vulcanization process, which leads to scorch generation and hence poor quality of the tire.

This problem with the silane coupling agent can be even greater in the wet mixing master batch manufacturing process, where the moisture removal process that is not present in the dry mixing process, i.e. due to the large amount of heat applied during the drying process, results in scorching and the resulting poor quality of the tire and This is because the reprocessing rate increases.

In addition, in the production of a silica wet mixed master batch, the silane coupling agent also has a problem of degrading its properties by causing hydrolysis due to moisture in the silica slurry or rubber latex.

The present invention has been made to solve the above-mentioned conventional problems, a tire that can greatly improve the occurrence of scorch during the mixing process or drying process due to the -S4- polysulfide structure silane coupling agent and the resulting poor tire quality An object of the present invention is to provide a rubber composition and a method for producing the same.

The rubber composition for a tire using the silica wet mixed master batch according to the present invention and a method for producing the same have the following characteristic elements.

(1) Preparation of Silane Coupling Agent

Instead of the conventional TESPT having a polysulfide structure of -S _4- , a silane coupling agent (A) having the following structural formula is used.

The silane coupling agent (A) is -S ₄ - than the dissociation energy of the TESPT high structure _{-S 2 - (CH 2) 6} -S 2 - consists of a structure is thermally stable.

(2) pretreatment of silane coupling agent

    Since the silane coupling agent is liable to cause hydrolysis in an aqueous solution, in the present invention, the silane coupling agent is premixed with an aromatic oil as a softener for making tires to make an emulsion phase and then mixed with rubber latex in its stable state. It prevents the silane coupling agent from deteriorating due to hydrolysis.

Hereinafter, the rubber composition for tire production according to the embodiment of the present invention will be described in detail together with the manufacturing process.

Table 1 Silica Rubber Compositions of Examples (Unit: phr)

SBR Latex 400  * Kumho Petrochemical (Styrene: Butadiene = SBR latex halved at 40:60 weight ratio, 25% solids) Silica slurry 200  * Slurry with Rhodia Z-115 mixed with water at 25:75 weight ratio Silane Coupling Agent (A) 4 Aromatic oil 50  * Far Eastern Oil Painting Anti aging agents 0.4  * Kumanox coagulant 0.6  Magnesium sulfate 50% solution

Manufacturing method

1) Add 200 phr of silica slurry to the reactor and stir.

2) 4 phr of the silane coupling agent (A) and 50 phr of the aromatic oil were stirred, dropwise adding 54 phr of the silane coupling agent (A) -aromatic oil emulsion solution to the silica slurry of 1).

3) Add 400 phr of SBR latex and 0.4 phr of anti-aging agent to the mixture of 2) above, and stir.

4) Slowly add 0.6 phr of coagulant and stir.

5) The coagulum was firstly removed with a filter, then secondly with a centrifuge and dried with a vacuum-extruder to obtain a silica rubber composition (sample 1).

Table 2 Silica rubber composition of Comparative Example 1 (Unit: phr)

SBR Latex 400  * Kumho Petrochemical (Styrene: Butadiene = SBR latex reacted at 40:60 weight ratio, 25% solids) Silica slurry 200  * Slurry with Rhodia Z-115 mixed with water at 25:75 weight ratio Silane coupling agent 4  TESPT Aromatic oil 50  * Far Eastern Oil Painting Anti aging agents 0.4  * Kumanox coagulant 0.6  Magnesium sulfate 50% solution

Manufacturing method

The silane coupling agent is a conventional TESPT, except that the silane coupling agent and the aromatic oil are sequentially added without mixing into the emulsion phase in the same manner as in the above embodiment.

A silica rubber composition (sample 2) was obtained in the same manner as in the example of SBR latex, anti-aging agent, coagulant and drying method.

Table 3 Silica rubber composition of Comparative Example 2 (unit: phr)

SBR Rubber 100  * Kumho Petrochemical (Styrene: Butadiene = 40: 60% by weight of 100% solid rubber reacted by weight ratio) Silica 50  * Rhodia Z-115 Silane coupling agent 4 TESPT Aromatic oil 50  * Far Eastern Oil Painting Anti aging agents 0.4  * Kumanox

Manufacturing method

Silica rubber composition (Sample 3) by adding 100 phr of SBR rubber, 50 phr of silica, 4 phr of silane coupling agent, 50 phr of aromatic oil, 0.4 phr of anti-aging agent, and then mixed at 110 ℃ using a Bunbari mixer. Got.

The following vulcanized rubbers were prepared using the silica rubber compositions of Examples, Comparative Example 1 and Comparative Example 2, and then physical properties were tested.

[Table 4] Vulcanized Rubber Components

Comparative Example 2 ' Comparative Example 1 ' Example Remarks Sample 1 100 Sample 2 100 Sample 3 100 Dispersant (SDA) One One One Carbon black (N330) 20 20 20 Zincification 1.5 1.5 1.5 Wax One One One Stearic acid One One One sulfur 0.8 0.8 0.8 Vulcanization accelerator One One One

  * SDA: Flow polymer product

  * Vulcanization accelerator: N-cyclohexyl-2-benzothiazole sulfenamide

  Curing condition: 150 ℃ × 20

The physical property test results are as follows.

[Table 5] Property test results

  <Vulcanization Rubber Properties> Comparative Example 2 ' Comparative Example 1 ' Example Tensile Properties Hardness 100 102 113 300% modulus 100 105 121 The tensile strength 100 103 115 Dynamic properties 0 ℃ tanδ 0.159 0.160 0.163 60 ℃ tanδ 0.125 0.123 0.117 Wear characteristics Din wear 100 105 117

The tensile properties and wear characteristics are shown as the relative physical properties of each of the case of Comparative Example 2 '100, the physical properties of the rubber composition according to the embodiment of the present invention was found to be remarkably excellent.

In addition, the dynamic characteristics are measured using a Rheovibron tester, which means that the higher the 0 ° C tanδ value, the better the braking performance on the wet road surface, while the lower the 60 ° C tanδ value, the more the rotational resistance characteristics. It means excellent.

As shown in the test results table, the silica rubber composition according to the embodiment of the present invention was also found to be excellent in terms of dynamic properties.

As described above, according to the rubber composition of the present invention and a method for producing the same, to a silica rubber composition prepared by mixing a silica rubber composition prepared by a dry method, or a conventional silane coupling agent, ie TESPT on the rubber latex without pretreatment In comparison, a silica rubber composition for tires having significantly superior physical properties can be obtained.

Claims (5)

Rubber composition comprising a silane coupling agent (A) of the following structural formula.

The method of claim 1, The silane coupling agent (A) is a rubber composition, characterized in that mixed on the rubber latex in an emulsion state by mixing with the aromatic oil. A process for preparing a rubber composition comprising mixing a silica or silica slurry on a rubber latex with a silane coupling agent, a surfactant, a vulcanization accelerator, a process oil and a coagulant, and then solidifying and drying them together. A method of preparing a rubber composition, characterized in that the silane coupling agent (A) of the following structural formula is premixed with the aromatic oil to form an emulsion and then mixed with rubber latex in its stable state.

The method of claim 1, The content of the silane coupling agent is a rubber composition, characterized in that 2% by weight when the composition ratio of silica to 10% by weight to 50% by weight based on the total weight of the entire rubber composition. The method of claim 3, wherein The content of the silane coupling agent is a rubber composition, characterized in that 2% by weight when the composition ratio of silica to 10% by weight to 50% by weight based on the total weight of the entire rubber composition.