JPS6220212B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing small spherical amino-based tree particles having a particle size of 30 microns to 3 mm. The particles obtained by the practice of this invention are useful as fillers in polyamides and epoxy resins, and as colorants, filter aids, and thickening agents for paints.

It is known to use melamine resin particles as an organic filler for polyamide and epoxy resins.
Usually, such resin is a mechanically crushed product of a cured melamine resin, and is irregular in shape, coarse in texture, and opaque. Such pulverized products tend to have a lower filling rate than spherical fillers. Furthermore, when the objective is to produce a transparent resin molded product, there is a drawback that such an opaque filler cannot be used.

On the other hand, a water-soluble compound obtained by reacting a polyisocyanate compound and an alkylene oxande adduct of alcohol is mixed with urea and formalin, and then a curing agent consisting of an aqueous phosphoric acid solution is added to the mixture at 60 to 63°C. A white dispersion was obtained by carrying out a condensation reaction, and a whitening agent, urea, and water were added to this dispersion, and the reaction was carried out at 58 to 60°C. Furthermore, an aqueous solution of caustic soda was added to adjust the pH to 8.4. It is known to produce a urea resin dispersion with good storage stability that is useful as a coating agent for
issue).

The resin particles in such a dispersion are fine, about 1 to 3 microns, and are more difficult to separate than water.

The present inventor conducted various studies in order to obtain large particles with a particle size of 30 microns to 3 mm in a method in which resin particles are precipitated by reacting an amino compound and formaldehyde in a solvent. It has been found that resin particles having the desired particle size can be obtained by performing precondensation in an aqueous solvent and curing the precondensate in a mixed solution of water and a non-solvent of the condensate. , arrived at the present invention. Furthermore, the resin particles obtained by carrying out the present invention were transparent.

That is, in the present invention, a resin solution prepared by blending an acidic curing agent into an aqueous solution of a precondensate of formalin and an amino compound having a white turbidity point of 40° C. or higher is mixed with a nonsolvent of the precondensate, and the mixture is stirred. An amino resin characterized in that a precondensate is cured by heating a mixture of the resin solution and a nonsolvent at 40 to 90°C for 30 minutes to 1 hour to precipitate a transparent, small spherical amino resin. A method for producing particles is provided.

In the practice of the present invention, examples of amino compounds include compounds having an amino group ( _-NH2 ) such as melasin, urea, ammeline, and ammelide.

Examples of the acidic curing agent include mineral acids such as phosphoric acid, sulfuric acid, and hydrochloride, and organic acids such as para-toluenesulfonic acid, formic acid, and xylenesulfonic acid.

Nonsolvents for the amino resin precondensate include silicone oil, liquid paraffin, hexane, linear paraffins such as octane, benzene, toluene,
Examples include aromatic paraffins such as xylene, carbon tetrachloride, and the like.

Therefore, in order to produce an amino resin precondensate, an amino compound and an aqueous solution of formaldehyde (formalin) are mixed in the presence of an alkali catalyst such as caustic soda or caustic potash at a temperature of 60 to 90°C, preferably with a cloudiness point of 40°C or higher. is precondensed until the temperature reaches 60-70°C. The pH of the liquid containing the alkaline catalyst is 8-12.

Here, the cloudiness point refers to the point when a 3% aqueous solution of the amino resin precondensate is gradually cooled from 90°C.
The temperature at which cloudiness is observed in the liquid [Industrial Chemistry Magazine, Vol. 60 , No. 1, p. 567 (1957)].

If the cloudiness point of the precondensate is less than 40°C, the curing reaction time during particle production becomes undesirable.

The amount of formaldehyde charged per equivalent of the amino group of the amino compound is preferably 1/2 to 1 equivalent.
If necessary, a resin solid content may be prepared from the resin liquid by dehydration under reduced pressure.

The acidic curing agent is added to the aqueous solution of the precondensate thus produced, and the pH of the system is adjusted to 1-6.

This resin solution is mixed with the non-solvent of the precondensate, and reacted with stirring at a temperature of 40 to 90°C for 30 to 60 minutes to precipitate amino resin particles. At this time, it is also possible to incorporate a protective colloid agent such as polyvinyl alcohol, polyvinylpyrrolidone, or CMC into the mixed solution.

Also, add a dye to the mixture, such as Spiron Red.
2W (Hoyado Chemical product name), Solvent Yellow
56 (product name Oil Yellow GG-S, manufactured by Orient Chemical), Solvent Orange 72 (product name Diamond Resin Brown A, manufactured by Mitsubishi Chemical Industries), Solvent Blue 35 (product name Oil Blue N,
(manufactured by Orient Chemical Co., Ltd.), etc., the dye will be absorbed by the hardening resin particles, and transparent colored amino-based resin spherical particles will be obtained. Dye is a precondensate
It is used in a proportion of 0.001 to 1 part by weight per 100 parts by weight.

Non-solvents such as silicone oil are also incompatible with water, and this amount is 100 to 100 parts by weight per 100 parts by weight of the precondensate.
Used in a proportion of 900 parts by weight.

The spherical resin particles produced by heating and curing are washed with filtrate and water and dried to become commercial products. The resin particles have a particle size of 30 μm to 3 mm and are transparent. Resin particles having a desired spherical diameter can be determined depending on the dispersion strength of the resin liquid in a non-solvent.

These resin particles are useful as fillers for polyamides, epoxy resins, phenolic resins, unsaturated polyester resins, etc., and the dyed resin particles are useful as colorants.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 Into a stainless steel reactor equipped with a cooler, 630 g of melamine and 1215 g of 37% formalin were charged, and caustic soda was further added to adjust the pH of the liquid to 8.5. Then, at 80℃, the cloudy point is 62℃ (water miscibility
The condensation reaction was carried out until 110).

400 g of this precondensation resin aqueous solution was placed in another reactor, and 26 g of 35% hydrochloric acid was added thereto. After mixing well, 1200 g of silicone oil (YF-33 manufactured by Toshiba Silicon Co., Ltd.) was added.
The curing reaction was continued at 60°C for 1 hour under stirring conditions such that the resin liquid was dispersed into fine particles in silicone oil to produce resin particles. After filtering and washing, the resin particles were dried to obtain an average particle size. 380 g of transparent spherical fine particles with a diameter of about 100 microns were obtained.

Example 2 Melamine 518 was placed in a reaction vessel equipped with a condenser.
g, 124 g of urea, 1000 g of 37% formalin, and 16 g of polyvinyl alcohol “Gosenol T-330” (trade name) made by Nippon Gosei, and then 48 g of
% caustic soda aqueous solution to adjust the pH of the liquid to 11.5.
Heating to 80℃ to perform precondensation reaction, cloudy point 60℃
An aqueous solution of was obtained.

400 g of this precondensed resin aqueous solution was placed in another reaction vessel, 26 g of 35% hydrochloric acid was added, and after mixing thoroughly,
Add 1200g of liquid paraffin and heat to 60℃ while stirring.
The mixture was reacted for 1 hour to precipitate resin particles.

The resin particles were separated by filtering and washing with water, and then dried. The obtained resin particles were spherical with an average particle size of about 90 microns and were transparent.

Example 3 A mixed solution of 300 g of urea and 810 g of 37% formalin
A 48% caustic soda aqueous solution was added to adjust the pH to 9. Then, a precondensation reaction was carried out at 80° C. for 30 minutes while stirring.

Then, formic acid was added so that the pH of the aqueous solution was 4.2, to obtain an aqueous resin solution with a cloudy point of 60°C.

Take 400g of this aqueous solution and add 26g of 35% hydrochloric acid to it.
Add, mix well, and 1200g of liquid paraffin.
The mixture was added and reacted at 60° C. for 1 hour with stirring to precipitate resin particles.

The resin particles were separated by filtering and washing with water, and then dried. The obtained resin particles were spherical with an average particle size of about 60 microns and were transparent.

Example 4 Melamine 518 was placed in a reaction vessel equipped with a condenser.
g, 124 g of urea, 1000 g of 37% formalin, and 16 g of polyvinyl alcohol "Gohsenol T-330" (trade name) manufactured by Nippon Gosei, and then 48%
Add caustic soda aqueous solution to adjust the pH of the solution to 11.5, and reduce to 80.
A precondensation reaction was carried out by heating to .degree. C. to obtain an aqueous solution with a cloudy point of 60.degree.

400 g of this precondensed resin aqueous solution was placed in another reaction vessel, 26 g of 35% hydrochloric acid was added, and after mixing thoroughly,
A 2:1 mixture of silicone oil and carbon tetrachloride
1200g was added and reacted at 60°C for 1 hour with gentle stirring to produce resin particles.

The resin particles were separated by filtering and washing with water, and then dried. The obtained resin particles have an average particle size of approximately 2.5 mm.
It was spherical and transparent.

Example 5 Melamine 518 was placed in a reaction vessel equipped with a condenser.
g, 124 g of urea, 1000 g of 37% formalin, and 16 g of polyvinyl alcohol “Gosenol T-330” (trade name) made by Nippon Gosei, and then 48 g of
% caustic soda aqueous solution to adjust the pH of the liquid to 11.5.
Heating to 80℃ to perform precondensation reaction, cloudy point 60℃
An aqueous solution of was obtained.

400 g of this precondensed resin aqueous solution was placed in another reaction container, and 0.2 g of Hodogaya Chemical's dye "Spiron Red" and 26 g of 35% hydrochloric acid were added thereto. After mixing thoroughly, 1200 g of silicone oil was added, and the mixture was stirred for 60 min. The reaction was carried out at ℃ for 1 hour to precipitate resin particles.

The resin particles were separated by filtering and washing with water, and then dried. The obtained resin particles were spherical with an average particle size of about 85 microns, and were transparent and red.

Claims (1)

[Scope of Claims] 1. A resin solution prepared by blending an acidic curing agent into an aqueous solution of a precondensate of formalin and an amino compound with a cloudy point of 40°C or higher is mixed with a non-solvent of the precondensate, and the mixture is stirred. An amino-based amino resin characterized in that the precondensate is cured by heating the mixture of the resin solution and non-solvent at 40 to 90°C for 30 minutes to 1 hour to produce a transparent, small spherical amino resin. Method for producing resin particles. 2. The manufacturing method according to claim 1, wherein the amino compound is melamine, urea, or a mixture of both. 3. The manufacturing method according to claim 1, wherein the precondensate is cured in the presence of a dye.