JP4535777B2 - Cleaning method for rubber roll - Google Patents

Description

  The present invention relates to a method for cleaning a rubber roll for the purpose of removing a silane coupling agent.

  In recent years, there has been a strong demand for both low fuel consumption and improved wet grip performance of tires, and in order to solve this, silica is frequently added to rubber compositions used for tire treads. . Along with this, a silane coupling agent is used in combination for the purpose of improving the dispersibility of silica in the rubber component.

  However, by using a silane coupling agent, the unreacted portion of the silane coupling agent that could not react with silica during the production of the rubber composition adheres to a rubber roll such as a calender roll used in rubber production. Thus, there arises a problem that the adhesion between the calender roll and the rubber composition is increased. Previously, the compounding amount of silica and silane coupling agent was small, and the amount of rubber component was small, so it was not a big problem, but in recent years, especially silica, silane coupling agent and rubber component have been used in large quantities. Therefore, the increase in the adhesion of the rubber composition to the rubber roll by the silica and the silane coupling agent is a big problem.

  In order to solve the above problem, attempts have been made to reduce adhesion by blending a chemical called a processing aid. However, there has been almost no effect.

  Patent Document 1 discloses a method for cleaning a film processing roll. This method is a method for cleaning a processing roll in a film processing machine after using a processing solution, and using hydrogen peroxide water is not possible. Not listed. Therefore, it is not assumed about removing the silane coupling agent used in manufacture of a rubber composition, and reducing the adhesiveness of a rubber composition and a roll.

JP 7-98491 A

  An object of the present invention is to provide a method for cleaning a rubber roll for the purpose of removing the silane coupling agent adhering to the rubber roll and reducing the adhesion between the rubber composition and the rubber roll. .

  The present invention relates to a method for cleaning a rubber roll, wherein a cleaning agent comprising a sodium hypochlorite aqueous solution or a hydrogen peroxide solution is used.

  The pH of the cleaning agent is preferably adjusted to 8-13.

  The pH of the cleaning agent is preferably adjusted using sodium hydroxide, bicarbonate or carbonate.

  The bicarbonate is preferably sodium bicarbonate or potassium bicarbonate.

  The carbonate is preferably sodium carbonate or potassium carbonate.

  According to the present invention, the rubber roll is washed with a cleaning agent comprising a hydrogen peroxide solution, thereby removing the silane coupling agent adhering to the roll and reducing the adhesion between the rubber composition and the roll. be able to. Furthermore, the adhesiveness of the rubber composition and the roll can be further reduced by adjusting the cleaning agent to basic.

  In the method for cleaning a rubber roll according to the present invention, a cleaning agent comprising a sodium hypochlorite aqueous solution or a hydrogen peroxide solution is used.

  As the hydrogen peroxide solution contained in the cleaning agent, 1 to 35% is preferably used. If the hydrogen peroxide solution is less than 1%, the cleaning effect tends to be almost lost, and if it exceeds 35%, handling tends to be dangerous.

  The pH of the cleaning agent is preferably 8-13. If the pH is less than 8, the cleaning effect tends to be weak, and if it exceeds 13, the handling is difficult because it is strongly basic and dangerous, or the cleaning agent tends to corrode the rubber roll surface.

  In order to adjust the pH of the cleaning agent, sodium hydroxide, hydrogen carbonate, carbonate, sodium hydride and the like are used, but it is preferable to use hydrogen carbonate or carbonate because it is safe to handle. .

  Of the bicarbonates, sodium bicarbonate or potassium bicarbonate is preferably used because it is inexpensive and easily available.

  Of the carbonates, sodium carbonate or potassium carbonate is preferably used because it is relatively safe to handle.

  As the rubber roll to be cleaned by the cleaning method of the present invention, a calendar roll, an open roll, a rotor of a kneading machine such as a Banbury mixer, and the like, which are preferably used for manufacturing a rubber composition, particularly an adhesion problem occurs. A calendar roll is preferred because it is easy.

  Examples of the method for cleaning the rubber roll include a method of wiping the roll with a cloth soaked with the cleaning agent.

  In the production of a rubber composition containing 4 parts by weight or more of a silane coupling agent with respect to 100 parts by weight of silica, there arises a problem that an unreacted part of the silane coupling agent adheres to the roll. Need to be cleaned.

  The rubber roll cleaned by the cleaning method of the present invention has no problem of adhesion and is excellent in productivity.

  The present invention will be described in detail based on examples, but the present invention is not limited to the examples.

Hereinafter, various chemicals used in Examples and Comparative Examples will be described.
Diene-based synthetic rubber: Oil-extended SBR1712 manufactured by JSR Corporation (containing 37.5 parts by weight of oil per 100 parts by weight of rubber solid content)
Carbon black: Diamond Black 1 manufactured by Mitsubishi Chemical Corporation
Silica: Ultrasil VN3 manufactured by Degussa
Silane coupling agent: Si266 (bis (3-triethoxysilylpropyl) disulfide) manufactured by Degussa
Aroma oil: X140 made by JOMO
Anti-aging agent: NOCRACK 6C manufactured by Ouchi Shinsei Chemical Co., Ltd.
Vulcanization accelerator TBBS: Noxeller NS manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
Vulcanization accelerator SPG: Noxeller D manufactured by Ouchi Shinsei Chemical Industry Co., Ltd.
Hydrogen peroxide solution: A hydrogen peroxide solution manufactured by Wako Pure Chemical Industries, Ltd. diluted with water to give a 3% aqueous solution (pH 6)
Sodium hydroxide: Wako Pure Chemical Industries, Ltd. Sodium carbonate: Wako Pure Chemical Industries, Ltd. Sodium bicarbonate: Wako Pure Chemical Industries, Ltd.

Examples 1-5 and Comparative Examples 1-3
(Manufacture of unvulcanized rubber sheet)
Using a 1.7 L Banbury mixer, 137.5 parts by weight of a diene synthetic rubber (rubber solid content 100 parts by weight, oil content 37.5 parts by weight), silica 65 parts by weight, carbon black 15 parts by weight, silane coupling agent 6.5 parts by weight and 15 parts by weight of aroma oil were kneaded, and the kneaded product was discharged when the kneading temperature was 140 ° C. Next, using a 1.7 L Banbury mixer, 2 parts by weight of stearic acid, 3 parts by weight of zinc oxide and 1 part by weight of anti-aging agent were kneaded into the kneaded product, and the kneaded product was discharged when the kneading temperature was 130 ° C. . Further, using an open roll, 1.5 parts by weight of sulfur, 1 part by weight of vulcanization accelerator TBBS, and 0.5 part by weight of vulcanization accelerator DPG were kneaded to produce an unvulcanized rubber sheet.

(Preparation of open roll surface)
The manufactured unvulcanized rubber sheet was wound around two rolls (open roll), kneaded at a temperature of 50 ° C. for 10 minutes, and the action of peeling off the rubber from the open roll was performed once for a total of three times. At this time, the unvulcanized rubber sheet was replaced with a new one each time. In this way, the unreacted silane coupling agent was reacted with the open roll surface.

(Roll adhesion test)
The following processing was performed on each prepared open roll.

<Comparative Example 1>
No particular treatment was performed.

<Comparative Example 2>
Using a cloth soaked with water, the surface of the open roll was continuously wiped for 10 minutes.

<Comparative Example 3>
A sodium hydroxide aqueous solution having a pH of 11 was prepared, and the surface of the open roll was continuously wiped for 1 minute using a cloth containing the aqueous solution.

<Example 1>
The surface of the open roll was continuously wiped for 1 minute using a cloth containing hydrogen peroxide (pH 6).

<Example 2>
A 3% aqueous solution of sodium carbonate was prepared, and the aqueous sodium carbonate solution and hydrogen peroxide solution were mixed to prepare cleaning agent 1 (pH 11). And the open roll surface was continuously wiped for 1 minute using the cloth containing the cleaning agent 1.

<Example 3>
A 3% aqueous solution of sodium bicarbonate was prepared, and the aqueous sodium bicarbonate solution and hydrogen peroxide solution were mixed to prepare cleaning agent 2 (pH 8.5). Then, the surface of the open roll was continuously wiped for 1 minute using a cloth containing the cleaning agent 2.

<Example 4>
Wipe the surface of the open roll for 1 minute with a cloth containing a commercially available product, Highter (registered trademark) (made by Kao Corporation, made weakly alkaline by adding sodium hydroxide to an aqueous sodium hypochlorite solution). Continued.

<Example 5>
The surface of the open roll was kept wiped for 1 minute using a cloth containing a commercially available product, Wide Hiter (registered trademark) (made by Kao Corporation, made weakly alkaline by adding sodium carbonate to hydrogen peroxide solution). .

  After the treatment, a new unvulcanized rubber sheet was wound around an open roll and then kneaded for 30 minutes. After kneading, the degree of rubber peeling when the rubber was peeled off from the open roll was evaluated, and the adhesion was most difficult to peel off. The comparative example 1 was 5 points. The smaller the numerical value is, the easier it is for the rubber to be peeled off from the open roll, indicating that the adhesion is reduced and better.

  The test results are shown in Table 1.

Claims (6)

It consists hydrogen peroxide water, a method of cleaning rubber rolls used in the preparation of the rubber composition containing a silane coupling agent, which comprises using a cleaning agent to adjust the pH to 8-13. The cleaning method according to claim 1, which is a method for cleaning a rubber roll used in the production of a rubber composition containing 4 parts by weight or more of a silane coupling agent with respect to 100 parts by weight of silica. The cleaning method according to claim 1 or 2, wherein the pH of the cleaning agent is adjusted to 8.5 to 11. The cleaning method according to claim 1, 2, or 3, wherein the pH of the cleaning agent is adjusted using sodium hydroxide, hydrogen carbonate or carbonate. The cleaning method according to claim 4, wherein the bicarbonate is sodium bicarbonate or potassium bicarbonate. The cleaning method according to claim 4, wherein the carbonate is sodium carbonate or potassium carbonate.