JP2002363295A - Method for production of wet masterbatch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method safely producing a wet masterbatch including carbon black, and the masterbatch produced by the method. SOLUTION: This method produces the wet masterbatch including carbon black through a process obtaining a solution by dissolving a rubber in a solvent, a process adding the carbon black to the solution and agitating, and a reprecipitation process adding a poor solvent such as methanol to the solution under agitation or throwing the solution into the poor solvent such as methanol under agitation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a wet masterbatch, and more particularly to a method for producing a wet masterbatch containing carbon black.

[0002]

2. Description of the Related Art Conventionally, a wet master batch containing carbon black has generally been produced by a method in which carbon black is added to rubber in a latex state and solidified with an acid or the like while stirring. However, the use of an acid or the like in the coagulation step requires attention in operation.

It has been experimentally known that a solution-polymerized rubber is also dissolved in a solvent, carbon black is added thereto, and the mixture is agitated. Was. However, in this method, a large amount of the solvent is vaporized at once, which is very dangerous.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to safely produce a wet masterbatch containing carbon black.

[0005]

That is, the present invention provides a process for dissolving rubber in a solvent to obtain a solution, a process for adding carbon black to the solution and stirring the solution, and a process for dissolving the poor solvent while stirring the solution. And a method for producing a wet master batch comprising a step of reprecipitating the wet master batch.

In the above-mentioned method for producing a wet master batch, the poor solvent is preferably methanol.

[0007] In the above-mentioned method for producing a wet masterbatch, it is preferable to add more oil than a predetermined amount to the rubber solution.

Further, the present invention relates to a wet master batch obtained by the above-mentioned production method.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the method for producing a wet master batch of the present invention, a rubber is first dissolved in a solvent to obtain a solution.

As the rubber, styrene-butadiene rubber (SBR), butadiene rubber (BR), isoprene rubber (IR), natural rubber (NR), acrylonitrile-butadiene rubber (NBR), ethylene-propylene-diene rubber (EPDM), Diene rubbers such as butyl rubber (IIR) are exemplified.

Examples of the solvent for dissolving the rubber include aromatic compounds such as toluene and xylene, and hexane. The solvent is preferably added at a ratio of 1 to 5 liters per 100 g of the rubber (solid content). If the solvent is less than 1 liter per 100 g of rubber, the solution becomes a thick solution, and the carbon black to be subsequently added tends not to be dispersed. If it exceeds 5 liters, a large amount of poor solvent tends to be required in the rubber reprecipitation step described below. More preferably, the upper limit of the amount of solvent per 100 g of rubber is 3
Liter, lower limit is 1.5 liter.

Next, carbon black is added to the solution and stirred.

As carbon black, for example, S
AF, ISAF-HM, ISAF-LM, ISAF-H
S, HAF and the like. The amount of carbon black added is 20 parts by weight based on 100 parts by weight of the rubber (solid content).
It is preferable to set it to 150 parts by weight. If the compounding amount of carbon black is less than 20 parts by weight, the effect of improving the performance by producing a wet masterbatch tends to be small, and if it exceeds 150 parts by weight, the rubber becomes too hard and a large amount of oil (for example, 150 parts by weight) is used. Degree), the subsequent kneading tends to be difficult. More preferably, the upper limit of the amount of carbon black is 130.
Parts by weight, the lower limit is 30 parts by weight.

The stirring can be performed by any method.

Next, the solution is treated with a poor solvent with stirring to reprecipitate the solution. As the poor solvent, methanol,
Lower alcohols having 2 or less carbon atoms in ethanol are exemplified.

In order to treat the rubber solution obtained by dispersing the carbon black obtained in the above step with a poor solvent to cause reprecipitation, a method of pouring the rubber solution into the poor solvent while stirring the rubber solution is used. A method in which the poor solvent is charged while the solution is used can be used. At this time, the amount of the poor solvent is 150 to 50 with respect to the solvent 100 used for dissolving the rubber by volume ratio.
It is preferably set to 0. If the amount of the poor solvent is less than 150, re-precipitation will not be successful, and if it exceeds 500, the poor solvent will be wasted. In addition, when oil is blended in the rubber solution, the amount of extracted oil tends to increase.

In the method for producing a wet master batch of the present invention, the oil can be contained in the rubber solution before the treatment with the poor solvent. Examples of the oil include aroma oil and mineral oil.

When the oil is treated with a poor solvent, it can be eluted into the poor solvent. However, not all are eluted. For example, when methanol is used as a poor solvent, about half is eluted. Therefore, in the case of treating with methanol, if the rubber solution before the treatment contains twice the amount of the desired oil amount (predetermined amount), when the rubber solution is treated with methanol and reprecipitated, the desired amount of oil is reduced. A wet masterbatch can be obtained. Specifically, when using methanol as a poor solvent and obtaining a wet masterbatch having an oil amount of 10 to 120 parts by weight with respect to 100 parts by weight of rubber, the oil amount in the rubber solution before the treatment is reduced to the rubber (solid content). ) It is preferable to mix the oil so as to be 20 to 240 parts by weight with respect to 100 parts by weight.

Further, before treatment with a poor solvent, silica, talc, calcium carbonate,
A filler such as aluminum hydroxide can be included.

The reprecipitate obtained by the treatment with the poor solvent is completely removed from the solvent by vacuum drying or the like, and is kneaded as a master batch, that is, mixed with other rubbers and fillers according to use. And vulcanizing agents, vulcanizing aids, antioxidants, waxes, processing aids and the like.

The solvent used for dissolving the used rubber, the poor solvent such as oil and methanol can be separated and reused by distillation or the like.

[0022]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

Examples 1 to 5 <Chemicals Used> Oil-extended solution polymerization SBR (oil-extended S-SBR): Tuffden 3330 manufactured by Asahi Kasei Corporation (oil extension amount 37.5 parts by weight based on 100 parts by weight of SBR) Non-oil-extended solution polymerization SBR (Non-oil-extended S-SBR): Nippol NS116 manufactured by Zeon Corporation Carbon black: Show Black N220 manufactured by Showa Cabot Co., Ltd. Aroma oil: AH- manufactured by Idemitsu Kosan Co., Ltd. 58

<Production Method> Example 1 200 g of oil-extended S-SBR was dissolved in 3 liters of toluene, and 150 g of carbon black was added thereto and stirred to dissolve. Five liters of methanol was poured into this solution at once, and the rubber was re-precipitated at once. This reprecipitate was dried under vacuum to obtain a wet master batch.

Example 2 A wet master batch was produced in exactly the same manner as in Example 1.

Example 3 200 g of oil-extended S-SBR was dissolved in 3 liters of toluene, and 150 g of carbon black and aroma oil 5 were added thereto.
4.5 g was added and stirred to dissolve. Five liters of methanol was poured into this solution at a stretch to reprecipitate the rubber. This reprecipitate was dried under vacuum to obtain a wet master batch.

Example 4 145.5 g of oil-extended S-SBR was dissolved in 3 liters of toluene, and 150 g of carbon black and 109 g of aroma oil were added thereto and dissolved by stirring. Five liters of methanol was poured into this solution at a stretch to reprecipitate the rubber.
This reprecipitate was dried under vacuum to obtain a wet master batch.

Example 5 145.5 g of non-oil-extended S-SBR was dissolved in 3 liters of toluene, and 150 g of carbon black and 54.5 g of aroma oil were added thereto and stirred to dissolve. Five liters of methanol was poured into this solution at a stretch to reprecipitate the rubber. This reprecipitate was dried under vacuum to obtain a wet master batch.

<Test Method> Each reprecipitate was extracted with acetone.
The extract was dried, and the weight of the extract was measured to determine the amount of oil.

Next, the extracted rubber was subjected to TGA (thermogravimetry). The rubber after the extraction was heated to burn the rubber first, and the weight loss was measured to obtain the rubber amount. Further raise the temperature to burn carbon black,
The weight loss was measured and defined as the amount of carbon black.

<Test Results> The results are shown in Table 1.

[0032]

[Table 1]

As shown in Table 1, the oil was dissolved in methanol, and the amount of oil contained in the obtained wet master batch was about half of the amount initially charged.
From this, it can be seen that a wet masterbatch having an almost desired oil amount can be obtained by first adding about twice the desired amount of oil.

In addition, comparing Examples 1 and 2, it can be seen that a wet masterbatch can be produced with good reproducibility by the method of reprecipitating the rubber solution with a poor solvent.

[0035]

According to the method for producing a wet master batch of the present invention, a wet master batch is obtained by reprecipitating a rubber solution with a poor solvent, so that a wet master batch can be produced safely.

In the reprecipitation step, the oil in the rubber solution is partially eluted, but by mixing the oil more than desired in the rubber solution in advance, a wet masterbatch containing a desired amount of oil is obtained. be able to.

The solvent used for dissolving the used rubber, the poor solvent such as oil and methanol can be easily separated by distillation or the like, and can be reused.

Claims (4)

[Claims] 1. A step of dissolving a rubber in a solvent to obtain a solution, a step of adding carbon black to the solution and stirring, and a step of treating the solution with a poor solvent while stirring and reprecipitating the solution. Manufacturing method of wet masterbatch. 2. The method according to claim 1, wherein the poor solvent is methanol. 3. The method according to claim 1, wherein the rubber solution contains more than a predetermined amount of oil. 4. A wet masterbatch obtained by the production method according to claim 1, 2 or 3.