JPH0348943B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a granular product of an amine antioxidant, and a method for efficiently producing a granular product of an amine antioxidant with excellent fluidity and low disintegration. Regarding how to.

Amine anti-aging agents for rubber, e.g. 4,4'-
Amine-based anti-aging agents for rubber that are solid at room temperature, such as dioctyl diphenylamine, are commercially available as powder or flake products, but these are said to scatter dust when used, worsening the working environment. There's a problem. In addition, when measuring during use, since it is in the form of powder or flakes, it has poor fluidity, which not only hinders automatic measurement, etc.
It is well known that flake products have problems such as the formation of powder during transportation, compounding, etc. operations. For this reason, regarding a method for producing a granular product of an amine-based anti-aging agent, Japanese Patent Application Laid-Open No. 54-62245 discloses that a powdered organic rubber chemical is dispersed in water containing 0 to 30% by weight of an organic solvent. After that, the method of heating and molding, and the method of
No. 202332 proposes a method in which a molten organic rubber chemical is added to an aqueous solution prepared by dissolving an anionic surfactant or an amphoteric surfactant. However, in these methods, the 4,4'-
When molding dioctyl diphenylamine, good granules cannot be obtained and the method is not satisfactory.

For these reasons, the present inventors have attempted to produce granular products of the above-mentioned amine-based anti-aging agents that have excellent fluidity, low disintegration, and do not generate dust, in a simple manner with a good yield. As a result of intensive study on the method for obtaining the above, the present invention has been completed.

That is, the present invention involves adding an organic solvent and a powdered amine anti-aging agent to an aqueous solution containing an anionic surfactant dissolved therein, and then forming the mixture into granules by heating while stirring. This is a method for producing a granular product of an amine-based anti-aging agent, which comprises:

Examples of the anionic surfactants used in the present invention include alkyl sulfate salts, alkylaryl sulfonate salts, alkylnaphthalene sulfonate salts, alkylmethylaminocarboxylic acid salts, sulfosuccinate salts, polyoxyethylene alkyl salts, Various types of anionic surfactants are exemplified, such as alkylaryl sulfates. Among these, alkylaryl sulfonates are particularly good. The amount of anionic surfactant to be used is not particularly limited, but the concentration in the aqueous solution is in the range of 0.01 to 5% by weight, preferably 0.05 to 1.0% by weight.

The organic solvent of the present invention is not particularly limited as long as it is an organic solvent that does not mix with water, and examples include n-hexane, benzene, toluene, xylene, and halogenated hydrocarbons. Among these organic solvents, tetrachlorethylene exhibits good effects. The amount of these organic solvents used is 0.1 to 10% by weight, preferably 0.5 to 3% by weight, based on the water containing the organic solvent.

When the organic solvent and surfactant in the present invention are present in an aqueous solution, the molten amine-based anti-aging agent is well dispersed in water as granular dispersed particles during the process of solidification, and the dispersed particles interact with each other. It appears to produce excellent effects such as preventing the adhesion of particles, forming smooth granules on the surface, and suppressing the adhesion of particles to walls, stirring blades, etc.

This significantly improves the quality and yield of the resulting granular product. The amine-based anti-aging agent of the present invention is a known amine-based anti-aging agent that is a powder at room temperature, and amine-based anti-aging agents such as 4,4'-dioctyl-diphenylamine can be used. The weight ratio of these amine antioxidants and the aqueous solution is preferably 5 to 50% by weight, preferably 10 to 30% by weight, based on the slurry concentration of the produced granules.

The temperature of the aqueous solution may be at most the boiling point of water, and the cooling temperature and strength of stirring can be adjusted as appropriate depending on the size of the desired granular product. There is no particular restriction on the order in which the organic solvent and the powdered amine anti-aging agent are added to the aqueous solution, and either may be added first or may be added at the same time.

Thus, in the present invention, the amine anti-aging agent obtained in powder form is added as it is to an aqueous solution in which an organic solvent and an anionic surfactant are dissolved, without being heated and melted, and the mixture is stirred. The powdered amine anti-aging agent can be made into granules in an aqueous solution by heating to form granules and then cooling.

If this granular product is separated from the aqueous solution and dried, a granular product with a particle size of approximately 0.5 to 2 mm, excellent fluidity, and resistant to disintegration can be obtained at a good yield.

The present invention will be explained below with reference to Examples.

Example 1 Powdered 4,4'-dioctyldiphenylamine
Add 150 g of tetrachlorethylene to an aqueous solution containing 1.5 g of tetrachlorethylene and 1% by weight of an anionic surfactant, raise the temperature to 85°C with stirring to form granules, then cool and filter. Take, dry and melt
149 g of granules having an average particle size of about 0.5 mm were obtained at 100.5°C.

Example 2 Powdered 4,4'-dioctyldiphenylamine
Add 150g to an aqueous solution containing 3.0g of toluene and 0.5% by weight of anionic surfactant, raise the temperature to 80°C with stirring and form into granules, then cool, filter, and dry. As a result, 149 g of granules having a melting point of 101° C. and an average particle size of about 0.7 mm were obtained.

Example 3 Powdered 4,4'-dioctyldiphenylamine
Water prepared by dissolving 150g of chlorobenzene 1.5g and anionic surfactant 0.5% by weight was heated to 85°C, then cooled, filtered, and dried to obtain a solution with a melting point of 100.5°C.
149 g of granules with an average particle size of 0.7 mm were obtained.

Comparative Example 1 Powdered 4,4'-dioctyldiphenylamine
150g was added to an aqueous solution containing 30g of tetrachlorethylene, and the temperature was raised to 80℃ while stirring, but due to poor dispersion, some of the particles formed into lumps, making it impossible to obtain a stable particle size.After cooling and filtration, the particle size was 0.5. It became a granule product with a variation of ~4 mm.

Comparative Example 2 Melted 4,4'-dioctyldiphenylamine
150 g was added to an aqueous solution at 40° C. in which 1% by weight of an anionic surfactant was dissolved, stirred, cooled and solidified, and the solidified particles were filtered and dried. The obtained particle size varied from 0.5 mm to 6 mm, and some of the filtration performance was inhibited by the generation of fine particles.
Moreover, the hardness of the particles was too high compared to the product of the present invention, and it was not possible to obtain particles with suitable hardness for use.

Claims (1)

[Claims] 1 Add an organic solvent and a powdered amine anti-aging agent to an aqueous solution containing an anionic surfactant, heat it with stirring to form it into granules, and then cool it. A method for producing a granular product of an amine-based anti-aging agent.