JPS6340818B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a spherical product of an amine-based anti-aging agent, and more specifically, the present invention relates to a method for producing a spherical product of an amine-based anti-aging agent. This invention relates to a method for producing a spherical product of an antiaging agent, and its purpose is to obtain a spherical product with excellent fluidity and low disintegration.

N-isopropyl-N'-phenyl-p-phenylenediamine, N-1,3-dimethylbutyl-
N′-phenyl-p-phenylenediamine, etc.
Diphenylamine anti-aging agents for rubber, which are solid at room temperature, are commercially available as flakes and rods, but these are easily disintegrated and turn into powder during transportation, causing dust to scatter during use and causing problems during work. The problem was that it significantly degraded the environment. In addition, especially for low-melting compounds such as N-1,3-dimethylbutyl-N'-phenyl-p-phenylenediamine, a small amount of powder may solidify into blocks, so It is necessary to remove the fine powder by sieving, which causes a significant decrease in yield, and it is also necessary to improve the melting point of the product surface or to pack it in a rigid container to prevent it from collapsing during transportation. There were problems such as the occurrence of

Further, in recent years, automatic metering has progressed in tire manufacturing and other compounding processes in the rubber industry, and with this, it has become necessary to continuously and meterly supply anti-aging agents in fixed amounts. Furthermore, improvements have also been made in which several types of compounding agents are pre-mixed uniformly in advance. However, conventional product forms such as flakes and rods have poor fluidity, making it difficult to meter and supply them in fixed amounts, and also having poor mixing properties during pre-compounding treatment.

Possible methods for making the anti-aging agent into spheres include pelletizing it and then making it into spheres using a marmerizer, dropping it onto a belt flaker and solidifying it to make it hemispherical. However, these methods require special machinery and require large equipment costs to increase production capacity.

On the other hand, a method for obtaining spherical products by dispersing a molten anti-aging agent in a solution consisting of a gel component of a hydrophilic polymer compound and water, and cooling and solidifying the dispersed particles while stirring (Japanese Patent Publication No. 48-3210 (No.) is also known, but this method uses a large amount of a hydrophilic polymer compound, which deteriorates the quality of the product, and if the amount of hydrophilic polymer compound used is reduced, the yield of spherical products decreases. There are drawbacks such as the extremely low temperature, the tendency to disintegrate, and the generation of fine powder.

In addition, powdered organic rubber chemicals are added in an amount of 0 to 30% by weight.
There is a method of dispersing and heating in water containing an organic solvent and molding it (Japanese Patent Application Laid-Open No. 1983-62245). This method is
This method requires two steps: once the product is taken out as a solid, it is turned into slurry again, and then dried, which results in a large loss of time and cost, and also requires expensive solvents.

For these reasons, the present inventors have developed an inexpensive, spherical product with a constant particle size that has excellent fluidity, low disintegration, and does not generate dust for the diphenylamine-based antiaging agent for rubber as described above. As a result of intensive research into a method for easily obtaining it with high yield, the present invention has been completed.

That is, in the present invention, a molten diphenylamine antioxidant is added to an aqueous solution containing an amphoteric surfactant at a slurry concentration of 5 to 5.
The present invention provides a method for obtaining a desired spherical product having a diameter of 1 to 6 mm in a high yield by adding 40% by weight, stirring, and solidifying by cooling.

The amine-based anti-aging agent applied to the present invention is a conventionally known diphenylamine-based anti-aging agent for rubber that is solid at room temperature, and in particular, N-isopropyl-N'-phenyl-p-phenylenediamine,
and N-1,3-dimethylbutyl-N'-phenyl-p-phenylenediamine are effectively applied.

The amphoteric surfactants used in the present invention include N, N,
N-trialkyl( _C8 - _C24 )-N-carboxyalkyl( _C1 - _C4 ) ammonium betaine type amphoteric surfactant; N-alkyl( _C8 - _C24 ) aminoalkylcarboxylic acid, N,N- Aminocarboxylate type amphoteric surfactants such as dialkylaminoalkylcarboxylic acids, N-alkyl ( _C8 to _C24 ) amino-N,N-bisalkyl ( _C1 to _C4 ) carboxylic acids, or salts thereof; Examples include 2-alkyl( _C8 - _C24 )-N-carbosialkyl( _C1 - _C4 )-N-hydroxyethylimidazolinium betaine type amphoteric surfactants. Specifically, N-lauryl-
N,N-dimethyl-α-carboxylic acid betaine, N
-tetradecyl-N,N-dimethyl-α-carboxylic acid betaine; N-tetradecylamino-N,N
-Alkali salts of bispropionic acid, N,N-dilaurylaminopropionic acid, N-lauryl-β-aminopropionic acid, N-laurylamino-N,N-bispropionic acid; 2-lauryl-N-carboxymethyl Examples include -N-hydroxyethylimidazolinium betaine, 2-tetradecyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine, and the like. These may be used alone or in combination of two or more.

When these amphoteric surfactants are present in an aqueous solution, the molten diphenylamine anti-aging agent is dispersed as spherical dispersed particles during the process of solidification, and agglomeration due to adhesion of these dispersions to each other is prevented. Since it becomes a spherical body with a smooth surface, it is possible to minimize the generation of fine powder, and it also has the excellent effect of suppressing the drop in yield due to adhesion to the walls of the container, stirring blades, etc. I found it. Amphoteric surfactants are generally less toxic;
It is known as a cleaning agent that has strong bactericidal power, excellent resistance to hard water, good compatibility with cationic, anionic, and nonionic surfactants, and provides antistatic ability, but it is a molten organic compound. It is a new and surprising fact, which has not yet been known, that it has the ability to spheroidize, especially diphenylamine-based anti-aging agents.

Note that a spheroidization method (Japanese Patent Application Laid-open No. 39738/1983) in which a polymeric anti-aging agent with a high solidification rate is dropped in a molten state from a nozzle into water containing a surfactant is known. The expected effect of the activator is simply to level out the surface tension,
It has not been known to use a surfactant to spheroidize substances such as diphenylamine anti-aging agents, which have a low solidification rate and whose solidification rate is actually reduced by rapid cooling. In order to increase productivity and obtain spherical products with good yield in spheronizing such substances, it is necessary to select a surfactant that is compatible with the physical properties of the substance to which it is applied. The present inventors investigated a number of surfactants and found that an aqueous solution of an amphoteric surfactant has excellent performance in spheroidizing diphenylamine anti-aging agents, which led to the completion of the present invention. be.

There are no particular restrictions on the amount of amphoteric surfactant used, but
In an aqueous solution, the concentration is usually in the range of 0.001% to 5% by weight, preferably in a trace amount of 0.01% to 2% by weight to exert sufficient effects.

The pH of the aqueous solution varies depending on the type of amphoteric surfactant used and the applied diphenylamine anti-aging agent, but is usually in the range of 5 to 13, preferably in the range of 6 to 10. The temperature of the aqueous solution may be below the freezing point of the applied diphenylamine anti-aging agent.

A spherical product is obtained by adding the above diphenylamine anti-aging agent in a molten state to an aqueous solution prepared by dissolving such an amphoteric surfactant, stirring, and cooling to solidify.

Here, the method of adding the molten diphenylamine anti-aging agent to the aqueous solution is not particularly limited, and may be added gradually or rapidly. However, in the present invention, since the molten anti-aging agent is stirred in an aqueous solution to be dispersed and solidified, the amount of diphenylamine-based anti-aging agent added to the aqueous solution is 5% by weight as the slurry concentration of the produced spherical products. The content should be ~40% by weight. Preferably, the slurry concentration is between 10% and 30% by weight. The particle size of the dispersed particles can be adjusted by arbitrarily changing the cooling rate and the strength of stirring.

Note that it is effective to add seed crystals to the aqueous solution or melted diphenylamine anti-aging agent because it also accelerates the solidification rate.

Furthermore, in the present invention, an antifoaming agent may be added if necessary. Furthermore, in order to further enhance the properties of the amphoteric surfactant, a nonionic surfactant, an anionic surfactant, a hydrophilic polymer compound, a flocculant, etc. may be added.

In this way, the molten diphenylamine anti-aging agent is dispersed as spherical dispersed particles in the aqueous solution.
The desired particle size is obtained. If the solidified spherical particles are separated from the aqueous solution, washed and dried, they will have a diameter of about 1
~6mm, with excellent fluidity and difficult to disintegrate,
Spherical products suitable for continuous metering and uniform blending are obtained with good yields.

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

Example 1 Molten N-1,3-dimethylbutyl-N'-
100 parts of phenyl-p-phenylenediamine was added to water.
500 parts and N-lauryl-N,N-dimethyl-α-
When added to a solution of 0.5 part betaine carboxylate at 40°C and stirred at room temperature for 40 minutes, the dispersed particles are completely solidified. After filtering, washing and drying, 98 parts of a spherical product with a melting point of 50° C. and a diameter of 1 to 6 mm was obtained, which had excellent fluidity and did not easily disintegrate.

Example 2 Molten N-1,3-dimethylbutyl-N'-
100 parts of phenyl-p-phenylenediamine, 2
-Lauryl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine 0.2 parts and water
Added over 10 minutes to a solution of 500 parts at 45°C,
After stirring for 1 hour at room temperature, completely solidified spherical particles are produced. After filtering, washing and drying, the diameter of
99 parts of spherical products of ~5 mm were obtained.

Example 3 Molten N-isopropyl-N'-phenyl-
100 parts of p-phenylenediamine, 400 parts of water and N-
When added to a solution of 0.15 parts of sodium lauryl amino-N,N-bispropionate at 65°C and stirred at room temperature for 20 minutes, the dispersed particles are completely solidified. After filtering, washing and drying, 97 parts of a spherical product with a melting point of 75° C. and a diameter of 1 to 4 mm was obtained, which had excellent fluidity and did not easily disintegrate.

Claims (1)

[Claims] 1 In an aqueous solution containing an amphoteric surfactant,
A molten diphenylamine anti-aging agent is added so that the slurry concentration of the anti-aging agent becomes 5 to 40% by weight, stirred, and solidified by cooling.
A method for producing a spherical product of an amine-based antiaging agent, characterized by obtaining a spherical product of mm.