JP3135133B2 - Fine powder resin and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a fine powdery resin comprising a crystalline resin as a core, an amorphous resin such as a styrene resin and an acrylic resin as a shell, and a surface coated with a polyester resin. It is related to the manufacturing method.

[0002]

2. Description of the Related Art Conventionally, a general method for producing a fine powder resin includes a mechanical method of mechanically pulverizing resin pellets and a method of dissolving resin pellets at a high temperature of an appropriate solvent and cooling the resin pellets to obtain a fine powder. There is a chemical method for obtaining a precipitate and obtaining the precipitate. However, the shape of the powdered resin obtained by the most general-purpose mechanical pulverization method becomes a powder with a so-called "whisker" in any resin, resulting in poor fluidity, which is a great obstacle in molding and transporting. I have.

[0003] Powder obtained by a chemical method has a shape closer to a sphere than powder obtained by a mechanical pulverization method, and is excellent in particle diameter and particle size distribution. However, resins that can be pulverized by this method are limited to resins having a high degree of crystallinity, such as polyethylene resins and polyamide resins. For this reason, it is necessary to use a mechanical pulverization method for a low-crystalline or amorphous resin, and it has been extremely difficult to industrially produce spherical fine particles having good fluidity or satisfactory fine particles having a good classification yield.

Therefore, amorphous resins such as styrene resins, acrylic resins and rosin resins have excellent compatibility with dyes, organic pigments, twisting agents, various adhesives, and many other resins. Nevertheless, it has been difficult to efficiently produce spherical fine powder having good fluidity. Also, it has not been easy to coat a different resin on the surface of a resin powder of a crystalline resin such as polyethylene, polypropylene, wax, or the like, which is not compatible with other resins, and modify the surface of the resin powder.
Generally, a method of mechanically driving ultrafine powder into the surface of a resin powder serving as a nucleus and a method of microencapsulation by an interfacial polymerization method have been adopted, and the production method is complicated, low-efficiency and expensive.

[0005]

In order to solve the above-mentioned problems, the present inventor has proposed a method of preparing a crystalline resin for forming a nucleus and a shell having a higher solubility in a selected solvent. After dissolving together with the resin intended for the composition of the above, first, crystalline resin fine particles are precipitated, and the surface thereof is coated with a modified resin to obtain a spherical fine powder excellent as a functional resin having good fluidity. They considered producing the resin all at once.

[0006]

That is, according to the present invention, when the thermoplastic resin is dissolved by heating in a solvent, the solubility of the (A) crystalline resin and (B) the solvent to be used is larger than that of the (A) component. After heating and dissolving the amorphous resin and / or the crystalline resin in a solvent, by cooling or adding a poor solvent, the particulate component (A) is first precipitated, and then the precipitation temperature of the component (A) By removing the solvent below,
We have developed a finely powdered resin characterized by having a two-layer structure with the component (A) as a core and the component (B) as a shell.

The core component (A) used in the present invention includes polyethylene, acid-modified polyethylene, polypropylene, poly (4-methylpentene-1), and polybutene.
-1 and other crystalline polyolefin polymers, ethylene-
Vinyl acetate copolymer (hereinafter abbreviated as EVA), modified EV
A, crystalline polyolefin copolymers such as ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer, and modified products thereof, nylon-6, nylon-6.
6, crystalline polyamide resins such as nylon-12, crystalline polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyacetals, and various synthetic or natural waxes.

The component (B) used as the shell in the present invention includes polystyrene, styrene-acryl copolymer, styrene resin such as ABS, vinyl chloride resin, vinyl acetate resin, vinyl resin such as polyvinyl butyral, and ethyl cellulose. Cellulose resin such as cellulose acetate, methacrylic resin, acrylic resin, polyamide resin, polyester resin, polyethylene, EVA, modified EV
A, a resin soluble in a solvent such as a rosin-based resin.
In the present invention, a plurality of types of component (A) may be used.
If the solubility of the component (B) in the solvent used is higher than that of the component (A), a plurality of different types of resins can be used as the shell.

The solvent used in the present invention may be any solvent which can completely dissolve the components (A) and (B) by heating, and specific examples thereof include linear butane, pentane, heptane and octane. Or branched or low molecular weight paraffins, aromatic compounds such as benzene, toluene, xylene, tetralin, decalin or hydrogenated products thereof,
Examples include halogenated compounds such as trichloroethylene, perchlorethylene, chloroform, dichlorobenzene, trichlorobenzene, and chloronaphthalene, phenols, alcohols, polyhydric alcohols, chlorinated phenols, and cresol.

The amount of the solvent to be used with respect to the resin component used as the component (A) and the component (B) varies depending on the combination of the molecular weight of the resin, the ability to dissolve in the solvent, the dissolving conditions, and the like.
Generally, a solvent may be added in an amount of about 50 to 1000 parts by weight to 100 parts by weight of the resin component. As the combination of the component (A) and the component (B) used in the present invention, a component having a higher solubility in the solvent used than the component (A) is used for the component (B). As a specific example, a crystalline resin is used as the component (A),
When the amorphous resin is used as the component (B), the component (A)
In terms of component / (B) component / solvent used, polyethylene /
Polystyrene / xylene, polypropylene / polyacryl / perchloroethylene, EVA / polystyrene / toluene, polyamide / ethylcellulose / benzyl alcohol, polyethylene wax / rosin-modified phenolic resin / xylene. In addition, a crystalline resin may be used for both the component (A) and the component (B). In this case, it is necessary to combine the component (B) with one having a higher solubility in the solvent used than the component (A). Specific examples include combinations of polyethylene / polyester resin / xylene, polypropylene / EVA / perchloroethylene, and polypropylene / modified EVA / trichloroethylene.

In the production of the fine powdery resin of the present invention, a solvent is added to the crystalline resin (A) and the resin (B) having a higher solubility than the solvent (A) to be used, and the resin is heated and dissolved.
After that, it is confirmed that the resin (A) is sufficiently dissolved, and cooling or addition of a poor solvent is performed until the resin (A) precipitates. At this time, the precipitated resin (A) is in a state of being dispersed in a solution in which the resin (B) is dissolved. In this state, when the solvent is removed by distillation under reduced pressure at a temperature lower than the temperature at which the resin (A) is precipitated, a spherical fine powder having the resin (A) as a core and the resin (B) as a shell is obtained. At this time, the cooling is continued and the resin (B)
The same result may be obtained even if vacuum distillation is performed after the precipitation. When performing vacuum distillation, it is also effective to add another solvent for the purpose of azeotropic distillation. Further, after most of the good solvent is removed, the distillation temperature can be increased, which is effective.

[0012]

Example 1 50 parts by weight of low-density polyethylene (Petrocene 180, a product of Tosoh Corporation), 50 parts by weight of a styrene resin (GP stalloin 666, a product of Asahi Kasei Corporation), and 300 parts by weight of xylene were placed in an autoclave. Then, after heating and melting at 100 ° C. for 2 hours, the mixture was cooled to 40 ° C., whereby polyethylene was precipitated and a cloudy styrene solution was obtained. The polyethylene dispersion was subjected to vacuum distillation at 40 ° C. to remove xylene, whereby spherical fine powder having polyethylene as a core and a styrene resin as a shell was obtained.
When one of the spherical fine powders was analyzed by FTIR, a composite peak of polyethylene and styrene resin was obtained. Further, this spherical fine powder was thoroughly washed and dried using xylene, and then one FT of the obtained spherical fine powder was used.
IR analysis revealed no peak for the styrene resin but only a peak for the polyethylene resin. In the fine powdery resin of the present invention, the resin having an average particle size of 30 to 60 µ was 90% or more.

[0013]

Example 2 Low-density polyethylene (Petrocene 180, manufactured by Tosoh Corporation) 50 parts by weight, polyester resin (Polyester G-120SA, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) 50
The autoclave was heated and melted at 80 ° C. for 2 hours and then cooled to 50 ° C., whereby the solution became cloudy. Thereafter, vacuum distillation was performed at 50 ° C. to obtain a spherical fine powder having polyethylene as a core and a polyester resin as a shell.The fine powder resin of the present invention has a resin distribution having an average particle size of 50 to 50 μm. The sample of 100 μ was 90% or more.

[0014]

Example 3 50 parts by weight of EVA (Ultracene UE625, manufactured by Tosoh Corporation) and 5 parts by weight of polypropylene wax (Viscol 550-P, manufactured by Sanyo Chemical Industry Co., Ltd.) Styrene resin (GP Staloin 666, a product of Asahi Kasei Kogyo Co., Ltd.)
45 parts by weight were dissolved in an autoclave by heating at 80 ° C. for 2 hours together with 300 parts by weight of toluene, and then cooled to 40 ° C., whereby a cloudy liquid was obtained. To this was added 50 parts by weight of water, and distilled under reduced pressure at 40 ° C. to remove toluene.
The distillation was continued at reduced pressure to remove water, and a white powder was obtained. As a result of electron microscopic analysis, it was found that particles having styrene as a shell were formed at the core where the wax was dispersed in the EVA. In the fine powdery resin of the present invention, the resin having an average particle size of 30 to 60 µ was 90% or more.

[0015]

Example 4 Polypropylene wax (Viscol 550-P, manufactured by Sanyo Chemical Industries, Ltd.) as a core component 8
A resin powder was prepared under the same conditions as in Example 3 except that 0 parts by weight and 20 parts by weight of a rosin phenol resin (Tamanol 361, a product of Arakawa Chemical Co., Ltd.) were used as a shell component. A spherical powder with a particle size of 1.5μ was obtained. When this fine powder was used as an additive in an offset ink, the surface of the fine powder wax particles was modified with a rosin phenol resin, so that the compatibility with the ink varnish was improved and good printability was obtained. In the fine powdery resin of the present invention, the resin having an average particle size of 1 to 2 μm was 90% or more.

[0016]

Comparative Example 1 100 parts by weight of a styrene resin (GP Staloin 666, a product of Asahi Kasei Kogyo Co., Ltd.) and 300 parts by weight of xylene were heated and dissolved in an autoclave at 80 ° C. for 2 hours, and then heated to 50 ° C.
The resulting translucent sol was cooled to 50 ° C. and distilled under reduced pressure at 50 ° C. to remove xylene. As a result, a solid mass was obtained, and fine powder was not obtained.

[0017]

According to the production method of the present invention, when the crystalline resin as the nucleus is precipitated from the state in which the resin as the nucleus and the resin as the shell are simultaneously dissolved, the solvent is cooled or the poor solvent is removed under appropriate stirring. The resin is precipitated by the addition of. For this reason, the particles serving as nuclei to be deposited first are placed under extremely uniform precipitation conditions, and the particle diameter becomes constant. Further, the precipitated particles are soft because they contain the solvent in the particles, and become spherical while floating in the liquid.

Then, in order to deposit a resin serving as a shell on the particle surface to form a coating film, the fine powder obtained after desolvation is a particle having a spherical two-layer structure having excellent fluidity. And a powder having a sharp particle size distribution incomparable with conventional mechanical pulverization methods. or,
Unlike the mechanical pulverization method during the production, the resin itself is not subjected to extreme treatment and is not exposed to a high temperature, so that the resin does not deteriorate and a resin powder having stable physical properties can be obtained. In addition, the shell resin can be easily made of an amorphous resin such as polystyrene or polyacrylic resin or a resin with low crystallinity, which has been difficult to produce spherical fine powders in the past. Thus, the surface modification of polyolefin particles having poor properties can be performed, so that the use as a functional resin can be greatly exhibited.

Claims (3)

(57) [Claims] 1. When a thermoplastic resin is dissolved by heating in a solvent, (A) a crystalline resin and (B) an amorphous resin and / or a crystal having a higher solubility in a solvent to be used than the component (A). After heating and dissolving the reactive resin in a solvent, by cooling or adding a poor solvent, the granular component (A) is first precipitated, and then the solvent is removed at a temperature lower than the deposition temperature of the component (A). A method for producing a finely powdered resin, which has a two-layer structure comprising a component (A) as a core and a component (B) as a shell. 2. When a thermoplastic resin is dissolved by heating in a solvent, (A) a crystalline resin and (B) an amorphous resin and / or a crystal having a higher solubility in the solvent to be used than the component (A). After heating and dissolving the conductive resin in a solvent, cooling or adding a poor solvent causes the granular component (A) to precipitate first, and then removes the solvent at a temperature lower than the precipitation temperature of the component (A). , A fine powdery resin having a two-layer structure comprising the component (A) as a core and the component (B) as a shell. (3) The component (A) is an olefin resin,
3. The method for producing a fine powder resin according to claim 1, wherein the component (B) is a styrene resin, a polyester resin or an acrylic resin, and the fine powder resin according to claim 2.