JPH0115523B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing hydrous polyester spheres. More specifically, the present invention involves reproducing a water-in-oil emulsion obtained by dispersing an aqueous solution containing a water-soluble polymer in an unsaturated polyester containing a vinyl monomer into an aqueous solution containing the water-soluble polymer. The present invention relates to a method for producing hydrous polyester spheres characterized by crosslinking and curing after dispersion.

The hydrous polyester spheres obtained in the present invention have small pores on their surface and are therefore useful as carriers for immobilizing enzymes.

Conventionally, the method for obtaining polyester spheres is to form an unsaturated polyester resin consisting of an unsaturated polyester and a vinyl monomer copolymerizable with the unsaturated polyester into a water-in-oil reverse emulsion, and then stir this in an aqueous medium. A method of obtaining polyester spheres by curing the inverse emulsion as small droplets (Japanese Patent Application Laid-Open No. 48-90381)
After dissolving a polyester resin in an organic solvent that is immiscible with water, the liquid is emulsionized with water to form an oil-in-water emulsion, and then the oil-in-water emulsion is mixed with an organic solvent to dissolve the polyester resin. A known method is to add an organic solvent that is immiscible with water, which is a non-solvent, and to obtain polyester spheres from the solvent and the mixture (US Pat. No. 3,772,252).

However, polyester spheres obtained by conventional methods do not have small pores on the surface.

As a result of various studies to obtain polyester spheres having small pores on the surface, the present inventor discovered that water-in-oil obtained by dispersing an aqueous solution containing a water-soluble polymer in an unsaturated polyester containing a vinyl monomer. Type emulsion (hereinafter referred to as primary emulsion)
is redispersed in an aqueous solution containing a water-soluble polymer to form a (water/oil)/water emulsion (hereinafter referred to as a secondary emulsion), and then crosslinking and curing the secondary emulsion. It was discovered that polyester spheres having small pores on the surface and excellent mechanical strength and heat resistance can be produced by this method, and the present invention was completed.

The invention will be discussed in detail below.

The primary emulsion in the present invention is obtained by dispersing an aqueous solution containing a water-soluble polymer in an unsaturated polyester containing a vinyl monomer. Any method that can obtain a primary emulsion from an aqueous solution containing a water-soluble polymer may be used. A suitable method for forming a primary emulsion is, for example, adding an aqueous solution containing a water-soluble polymer little by little to an unsaturated polyester containing a vinyl monomer, and vigorously stirring with a homogenizer or the like (for example, 1000 to 3000 rpm). One method is to emulsify it. Another method is to add the entire amount of an aqueous solution containing a water-soluble polymer to an unsaturated polyester containing a vinyl monomer, and then stir vigorously with a homogenizer (e.g.
5000r.pm).

Furthermore, the obtained primary emulsion is added little by little to an aqueous solution (protective colloid liquid) containing a water-soluble polymer, and the secondary emulsion is uniformly redispersed by stirring (for example, 300 to 3000 rpm). The secondary emulsion is stirred thoroughly and slowly at room temperature or under heating (30 to 80°C) until the odor of the vinyl monomer disappears (40 to 80°C).
An aqueous slurry of unsaturated polyester microspheres can be obtained by crosslinking and curing the unsaturated polyester phase containing vinyl monomers at 80 rpm).

Although commercially available unsaturated polyesters containing vinyl monomers can be used, α, β-unsaturated dibasic acids or a mixture of these and saturated dibasic acids are used as the acid component and glycols are used as the alcohol component. It can be produced by adding a copolymerizable vinyl monomer to the reacted product.

Examples of α,β-unsaturated dibasic acids include maleic acid and fumaric acid, and examples of saturated dibasic acids include phthalic acid, succinic acid, adipic acid, and sebacic acid. Examples of glycols include ethylene glycol, propylene glycol, and glycerin.

Vinyl monomers include styrene, α-methylstyrene, vinyltoluene, vinyl acetate, methyl methacrylate, diallyl phthalate, acrylic acid, acrylic ester, methacrylic acid,
Examples include methacrylic acid ester, vinyl acetate, acrylonitrile, 2-ethylhexyl (meth)acrylate, and ethyl (meth)acrylate.

The vinyl monomer may be used in any amount based on the unsaturated polyester, but it is preferably about 50% or less in order to contain a large amount of aqueous solution.

Examples of water-soluble polymers used in the present invention to prepare an aqueous solution containing a water-soluble polymer and a protective colloid solution include gelatin, agar,
Examples include starch, casein, albumin, pectic acid, alginic acid, carboxymethyl cellulose, hydroxyethyl cellulose, polyvinyl alcohol, polyacrylamide, and sodium polyacrylate.

The above-mentioned aqueous solution and protective colloid containing the water-soluble polymer can be used as they are, for example, by mixing a certain amount of the water-soluble polymer into a certain amount of water at room temperature, stirring, and allowing the mixture to stand. In this case, the concentration of the water-soluble polymer during production of the primary emulsion can be from 1 to 30% by weight, but it is preferably about 10% by weight. Furthermore, as an aqueous solution (protective colloid liquid) containing a water-soluble polymer, the concentration of the water-soluble polymer can be 0.5 to 20% by weight.
It is preferable to use around 2% by weight. In the above, the concentration of the water-soluble polymer is determined by taking into consideration the type of unsaturated polyester used as a starting material in the present invention, the stability of the emulsion, the particle size of the target microspheres, the effect on the cured product, etc. It is desirable to increase or decrease the amount as appropriate.

As the polymerization initiator used for curing the oil phase of the secondary emulsion in the present invention, known radical polymerization initiators or redox polymerization initiators used for curing unsaturated polyesters can be used. Examples of radical polymerization initiators include potassium persulfate, ammonia persulfate, azobisisobutyronitrile, benzoyl peroxide, cumene hydroperoxide, t-butyl peroxide, methyl ethyl ketone peroxide, lauroyl peroxide, etc. Examples of the system polymerization initiator include benzoyl peroxide-dimethylaniline, methyl ethyl ketone peroxide-cobalt organic acid salt, and cumene hydroperoxide-cobalt organic acid salt (cobalt organic acid salts include cobalt naphthenate, cobalt octoate, etc.). The above polymerization initiator is used in an amount of 0.5 to 10 parts by weight per 100 parts by weight of unsaturated polyester containing a vinyl monomer. In addition, the cobalt organic acid salt of the redox polymerization initiator is 0.05
~1 part by weight is used, but it is desirable to increase or decrease the amount as appropriate, taking into consideration the type of water-soluble polymer, curing conditions, properties of additives, influence on the cured product, etc. The above polymerization initiator may be added in advance to the unsaturated polyester containing the vinyl monomer, or may be added after the primary emulsion is completed. When a redox-based polymerization initiator is used, it is necessary to shorten the time until re-emulsification after adding the polymerization initiator as much as possible.

The resulting aqueous slurry of unsaturated polyester microspheres is then separated from the aqueous solution by an operation such as centrifugation. When this separated product is washed with alcohol and air-dried, white unsaturated polyester microspheres with small pores on the surface are obtained.

The unsaturated polyester microspheres obtained by the present invention have the following properties.

a The unsaturated polyester microspheres have 1 on their surface.
It has small pores of ~10μ, and the inside is porous and filled with an aqueous solution (or gel) containing a water-soluble polymer.

b The diameter of the microspheres is 60-1800μ.

c The strength of the microspheres is strong.

d Separate the aqueous slurry as it is, and when dried, the water-soluble polymer is attached to the surface of the microspheres, so it can be easily dispersed in water.

Examples are shown below.

Example 1 100 parts of Polymer 6702 (Polymer: registered trademark, unsaturated polyester manufactured by Takeda Pharmaceutical Co., Ltd.) (means parts by weight; the same applies hereinafter) was stirred at a stirring speed of 2800 r.p.
8% aqueous gelatin solution while stirring at a speed of m.
25 parts were gradually added little by little to obtain a primary emulsion. To this primary emulsion were added 0.5 part of cobalt naphthenate and 1 part of methyl ethyl ketone peroxide, and after thorough stirring, the mixture was heated separately at 1500 r.
It was carefully added dropwise into 600 ml of 1% aqueous gelatin solution being stirred at pm. After the dropwise addition was completed, the mixture was stirred for an additional 3 minutes to obtain a secondary emulsion consisting of fine particles. After heating this secondary emulsion to 35-40°C, it was slowly stirred at a stirring speed of 200-300 rpm for 3-4 hours to crosslink and harden the oil phase, and then
Stirring was continued for 1 hour at ℃ to obtain a white-like slurry of water-containing resin spheres. This was transferred to a large excess of water 5, slowly stirred, allowed to settle, filtered, washed with methanol, and air-dried at 30°C. 125 parts of water-containing resin spheres containing gelatin gel and having small pores on the surface ( Yield approx.
100%). A scanning electron micrograph of the surface of the obtained water-containing resin sphere is shown in FIG. 1, and a scanning electron micrograph of the fractured surface is shown in FIG.

Example 2 In Example 1, 100 parts of Smearp MG-1 (Smearp: registered trademark, unsaturated polyester, manufactured by Sumitomo Chemical Co., Ltd.), 50 parts of an 8% gelatin aqueous solution, and a stirring speed of 1500 rpm during primary emulsion formation were used. The procedure was carried out in the same manner as in Example 1 except that 150 parts of water-containing resin spheres containing gelatin gel (yield: approximately 100 parts) were prepared.
%) was obtained.

Example 3 In Example 1, 100 parts of Polymer 6702 (unsaturated polyester, manufactured by Takeda Pharmaceutical Company Limited), 50 parts of 8% gelatin aqueous solution, stirring speed 5000 rpm during primary emulsion formation, protective colloid liquid for secondary emulsion The process was carried out in the same manner as in Example 1, except that 600 ml of a 2% aqueous gelatin solution was used as the gelatin gel, to obtain 147 parts (yield: about 98%) of hydrous resin spheres containing gelatin gel.

Example 4 The procedure of Example 1 was repeated except that 25 parts of an 8% starch aqueous solution was used to form the primary emulsion, and 125 parts of water-containing resin spheres containing starch gel were prepared (yield: approx. 100 parts). %) was obtained.

[Brief explanation of drawings]

FIG. 1 shows a scanning electron micrograph of the surface of the hydrous polyester sphere obtained in Example 1.
FIG. 2 shows a scanning electron micrograph of the fractured surface of the hydrous polyester sphere obtained in Example 1.

Claims (1)

[Claims] 1 A water-in-oil emulsion obtained by dispersing an aqueous solution containing a water-soluble polymer in an unsaturated polyester containing a vinyl monomer is redispersed in an aqueous solution containing a water-soluble polymer, and then cross-linked. A method for producing a hydrous polyester spherical body characterized by curing.