JPH0657006A - Production of polymer fine particle in non-aqueous solvent - Google Patents

Abstract

PURPOSE:To obtain the polymer fine particles having small particle diameters and having an uniform particle diameter distribution by utilizing the difference between the solvent solubilities of the first olefinic resin giving the polymer fine particles and the second olefinic resin as a dispersing agent in non-aqueous solvents. CONSTITUTION:(A) The first olefinic resin having COOH or ester groups (e.g. styrene-methacrylic ester copolymer) giving polymer fine particles and (B) the second olefinic resin having COOH o ester groups (e.g. styrene-acrylic ester copolymer) as a dispersing agent are dissolved in an A:B weight ratio of 1:1-0.05 in the first non-aqueous solvent (e.g. toluene), and subsequently mixed with the second non-aqueous solvent (e.g. isoparaffinic hydrocarbon) which is a poor solvent for the component A but is preferably compatible with the first non- aqueous solvent, thereby selectively depositing only the component A by the utilization of a difference between the solvent solubilities of the components A and B to produce the polymer fine particles having particle diameters of 1-5mum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing fine polymer particles for fillers or coloring materials.

[0002]

2. Description of the Related Art As a method for producing polymer fine particles,
A pulverization method, a polymerization method, and a precipitation method are known.

[0003]

As polymer fine particles for fillers or coloring materials, fine particles having a uniform particle size distribution are required. 5μm of polymer by pulverization method
A large grinding energy is required to grind up to the following, and the yield of fine particles having a desired particle size is low. Further, in the case of pulverization into fine particles, there are unavoidable drawbacks such as a broad particle size distribution and a non-uniform particle shape.

Although there are examples in which polymer particles having a uniform particle size are produced by a polymerization method, the polymerization conditions are extremely complicated and it is difficult to control the polymerization reaction. Furthermore, it is difficult to uniformly disperse the fine particles polymerized in the water system in the vehicle of the ink or paint or in the non-aqueous solvent as the primary particles. Further, there are some examples regarding the polymerization of polymer fine particles in a non-aqueous system, but it is a situation that it still takes days until practical use.

A method of precipitating polymer fine particles in a non-aqueous system by utilizing the temperature dependence of the solubility of the resin has been conventionally known, but most of the obtained resin fine particles have a particle size of 10 μm or more. Further, a method of adding a poor solvent to the resin in a solution prepared by dissolving the resin in a good solvent by utilizing the difference in the solubility of the resin depending on the solvent to precipitate polymer fine particles is known. The particles precipitated in the solvent have poor dispersion stability and are agglomerated and coalesced, which makes it difficult to obtain dispersion-stable fine particles.

In view of the above situation, the present invention provides polymer fine particles having a smaller particle size and a uniform particle size distribution as compared with conventional ones.
It was made for the purpose of producing in a non-aqueous solvent.

[0007]

Means for Solving the Problems The present invention solves the above problems by having a first olefin resin having a carboxyl group or an ester group in a first non-aqueous solvent and a carboxyl group or an ester group as a dispersant. The second olefin resin is dissolved to form a solution, and the solution is mixed with a second non-aqueous solvent that is a poor solvent for the first olefin resin to form a solution in the mixed solution. It can be solved by a method for producing fine polymer particles, which is characterized in that the olefin resin of No. 1 is deposited.

[0008]

According to the present invention, the first olefin resin, which becomes fine polymer particles, and the second olefin resin for the dispersant are both good solvents in the first non-aqueous solvent in the non-aqueous solvent. After being dissolved in, the second non-aqueous solvent, which is a poor solvent, is added to the first olefin resin to precipitate only the first olefin resin by utilizing the difference in solvent solubility between the two resins. Thus, polymer fine particles having a particle size of 1 to 5 μm and excellent in dispersibility are produced without any pulverization step.

The first olefin resin of the present invention and the second olefin resin used as the dispersant of the present invention are the same as the first olefin resin for the second non-aqueous solvent such as normal or isoparaffin hydrocarbon solvent. The olefin resin may be insoluble or sparingly soluble, and the second olefin resin may be soluble. Furthermore, both the first olefin resin and the second olefin resin are soluble in the first non-aqueous solvent, for example, an aromatic solvent such as toluene and benzene, and a ketone solvent such as methyl ethyl ketone. Specific examples of the resin having a carboxyl group or an ester group of the present invention include ethylene / vinyl acetate copolymer, (meth) acrylic resin,
Ethylene / acrylic acid copolymer, ethylene / methacrylic acid copolymer, styrene / acrylic acid copolymer, styrene / methacrylic acid copolymer, ethylene / acrylic acid ester copolymer, ethylene / methacrylic acid ester copolymer, Examples thereof include styrene / acrylic acid ester copolymers and styrene / methacrylic acid ester copolymers. Both the first olefin resin and the second olefin resin of the present invention are selected from these, and it is possible to use one kind or a mixture of two or more kinds having different molecular weights and molecular structures as required. it can. In the present invention, the ratio of the first olefin resin and the second olefin resin is preferably 1.0 to 0.05 parts by weight of the second olefin resin with respect to 1 part by weight of the first olefin resin. .

Examples of the first non-aqueous solvent that can be used in the present invention include aromatic hydrocarbons such as benzene and toluene, ketones such as methyl ethyl ketone, esters such as acetic acid ester, ethers such as ethyl ether and tetrahydrofuran. To be Further, as the second non-aqueous solvent, normal paraffin hydrocarbons such as n-hexane and n-heptane, trade names Isopar G, H, L, M (Exx
on company) and other isoparaffinic hydrocarbons. The first non-aqueous solvent and the second non-aqueous solvent used in the present invention are preferably compatible with each other.

The mixing ratio of the first non-aqueous solvent and the second non-aqueous solvent varies depending on the combination of "first olefin resin / first non-aqueous solvent / second non-aqueous solvent". It is preferable that the ratio of the second non-aqueous solvent is as high as possible within the range in which the first olefin resin is completely dissolved.

When the second non-aqueous solvent is added after the first olefin resin and the second olefin resin are dissolved in the first non-aqueous solvent, the first olefin resin is added to the second non-aqueous solvent. Is insoluble or slightly soluble and the second olefin resin is soluble, that is, the first olefin resin has a small affinity and the second olefin resin has a large affinity with the second non-aqueous solvent solvent, The first olefin-based resin is deposited to generate a polymer seed, and at this moment, the second olefin-based resin is adsorbed on the surface of the polymer seed to form an adsorption layer made of the second olefin-based resin. The adsorption layer made of the second olefin resin is a non-aqueous solvent (that is, the first and second
In the mixed solvent of the non-aqueous solvent and the second non-aqueous solvent alone) has the effect of suppressing the aggregation and fusion of the particles of the first olefin resin. As described above, due to the dispersing action of the second olefin resin, the polymer seeds generated from the first olefin resin grow individually without agglomerating and fusing with each other.
Fine particles of the first olefin resin having a particle size suppressed to 1 to 5 μm are deposited. As a result, polymer particles having a particle size of 1 to 5 μm and having good dispersion stability are formed in a non-aqueous solvent, that is, in a mixed solvent of a first non-aqueous solvent and a second non-aqueous solvent, without going through a pulverizing step. It has become possible.

Further, in the present invention, the first non-aqueous solvent in which the first olefin resin and the second olefin resin are dissolved is added to the second non-aqueous solvent to produce polymer fine particles. However, it goes without saying that the same operational effects as described above can be obtained.

In the present invention, the combination and blending ratio of the first olefin resin and the second olefin resin,
The shape and particle size of the precipitated polymer particles vary depending on the combination and mixing ratio of the non-aqueous solvent and the second non-aqueous solvent, and the conditions such as the vaporization rate of the non-aqueous solvent, the stirring rate and the reaction temperature.

In the present invention, a coloring agent such as a pigment or a dye may be added to the resin if necessary. As such a colorant, a colorant generally used as a colorant may be used. The amount of addition of the coloring material is preferably 0.05 to 1 part by weight based on 1 part by weight of the resin. The addition method may be such that it is added to the resin in advance by means such as heat kneading, or is added to the solution at the time of resin dissolution during the production process of the present invention or before the start of precipitation of the first olefin resin. According to.

In the present invention, additives such as cationic, anionic or nonionic surfactants and dispersants may be added to the solution before and after the deposition of the first olefin resin.

[0017]

The present invention will be described below with reference to specific examples, but the present invention is not limited to these examples. In addition, in the following examples, "first resin" is "first olefin resin".
And "second resin" means "second olefin resin". Moreover, the part in each table represents a weight part. [Example 1] A separable flask equipped with a reflux condenser and a stirring motor was used, and the first olefin resin, the second olefin resin, the pigment, the pigment dispersant, and the pigment shown in Table 1 were used in the flask. 1 non-aqueous solvent was added.

[0018]

[Table 1]

Next, the first olefin resin and the second olefin resin are completely dissolved while stirring and heating as needed, and then the second non-olefin resin of Table 1 is kept at room temperature while stirring is continued. By adding 300 parts of an aqueous solvent over 15 minutes, fine polymer particles made of the first olefin resin and colored with carbon black were deposited. The yield of the first olefin resin was 98%. The polymer particles thus obtained were particles as shown in the electron micrograph of FIG. 1, and had an average particle size of 3.5 μm.

Example 2 A separable flask equipped with a reflux condenser and a stirring motor was used, and the first olefin resin, the second olefin resin, the pigment, and the pigment dispersion shown in Table 2 were placed in the flask. The agent and the first non-aqueous solvent were added.

[0021]

[Table 2]

Next, the first olefin resin and the second olefin resin were completely dissolved while stirring and heating the above mixture as needed, and then while stirring was continued at room temperature as shown in Table 2. By adding 300 parts of the second non-aqueous solvent over 20 minutes, fine polymer particles made of the first olefin resin and colored with phthalocyanine blue were deposited. The yield of the first olefin resin was 94%.
The polymer particles thus obtained are particles as shown in the electron micrograph of FIG. 2, and have an average particle size of 4.3 μm.
Met.

Comparative Example 1 A separable flask equipped with a reflux condenser and a stirring motor was used, and the first olefin resin, the second olefin resin, the pigment, and the pigment dispersion shown in Table 3 were placed in the flask. The agent and the first non-aqueous solvent were added.

[0024]

[Table 3]

Subsequent operations were performed in the same manner as in Example 1 to deposit fine polymer particles made of the first olefin resin and colored with carbon black. Thus, the second
The particles obtained without adding the olefin resin of
As shown in the electron micrograph of the above, the particles were large particles having an average particle size of 25 μm.

Example 3 Polymer fine particles were deposited in the same manner as in Example 1 except that 80 parts of ethyl acetate was used as the first non-aqueous solvent. The polymer particles thus obtained had an average particle size of 4.0 μm.

Example 4 A separable flask equipped with a reflux condenser and a stirring motor was used, and the first resin, second resin, pigment, pigment dispersant and first resin shown in Table 4 were used in the flask. After adding the solvent and stirring and heating as necessary, the first resin and the second resin were completely dissolved and then stirring of this solution was continued, while stirring at room temperature. It was added to the non-aqueous solvent over 5 minutes to precipitate polymer particles of the first resin and colored with benzidine yellow. The average particle size was 2.5 μm.

[0028]

[Table 4]

Industrial Applicability As described above, according to the present invention, it is possible to produce fine polymer particles of the first olefin resin having a particle size of 1 to 5 μm and excellent in dispersion stability. The production method of the present invention has uniform particle diameter and particle shape compared to particles by a conventional pulverization method and becomes uniform particles, and since it is easy to control the production conditions of polymer fine particles as compared with a conventional polymerization method, good reproducibility, Particles can be generated. Furthermore, since the present invention is a method for producing fine polymer particles in a non-aqueous system,
It has an effect that it is easy to disperse the generated fine particles in the vehicle of the ink or paint or in the organic solvent.

[Brief description of drawings]

FIG. 1 is an electron micrograph (5000 times), which is a drawing and shows the structure of polymer fine particles obtained in Example 1 of the present invention.

FIG. 2 is an electron micrograph (7,000 times) as a drawing, which shows the structure of polymer fine particles obtained in Example 2 of the present invention.
Is.

FIG. 3 is an electron micrograph (× 1000), which is a drawing and shows the polymer particle structure obtained in Comparative Example 1 of the present invention.

Claims (1)

[Claims] 1. A first olefin resin having a carboxyl group or an ester group and a second olefin resin having a carboxyl group or an ester group as a dispersant are dissolved in a first non-aqueous solvent. A solution, and the first olefin resin is precipitated in the mixed solution by mixing the solution with a second non-aqueous solvent that is a poor solvent for the first olefin resin. The method for producing fine polymer particles.