JP2005343993A - Method for producing polymer fine powder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a polymer fine powder having a low glass transition temperature, and to provide a simple method for producing the polymer fine powder at a high yield and causing low environment load. <P>SOLUTION: The method comprises polymerizing a vinyl monomer represented by general formula (I) in supercritical carbon dioxide. In formula (I), X is H or methyl; Y is a structure having a structural unit represented by general formula (II) and having a terminal hydroxyl. In formula (II), m and n are each an integer of ≥1. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing a polymer fine powder in supercritical carbon dioxide.

  Polymer fine powder refers to a granular polymer with a small particle size. For example, a filler, an adhesive filler, a toner additive, and a liquid crystal that are included in a paint capable of forming a coating film having a design property. It can be used in applications such as industrial spacers, and its demand is increasing year by year.

Conventionally, such polymer fine powder has been produced by methods such as emulsion polymerization, suspension polymerization, and dispersion polymerization in an organic solvent. However, the emulsion polymerization method and the suspension polymerization method have a problem that it is necessary to remove water after the polymerization and the work is complicated. In addition, in the dispersion polymerization method in an organic solvent, since many organic solvents are flammable, there are dangers such as ignition and environmental / workability problems due to volatilization of the organic solvent.
In addition, in order to make a polymer obtained by polymerization by such a method into a fine powder, for example, the obtained polymer must be pulverized by a mechanical pulverization method. Not only is the production of the molecular fine powder complicated, but there is a problem in that a large amount of energy is required.

  Thus, as a measure for solving the above problem, a method of using a supercritical fluid having a unique property as compared with an organic solvent, water, or the like as a solvent in producing a polymer has attracted attention. Among the supercritical fluids, particularly supercritical carbon dioxide is not only harmless and nonflammable, but also has a feature that it can be easily removed by depressurization and can be easily reused.

  As a method for producing a polymer using supercritical carbon dioxide as a solvent, for example, a dispersion polymerization method for producing a polymer in supercritical carbon dioxide in the presence of a surfactant having fluorine or a siloxane segment has been reported. (For example, refer to Patent Document 1).

Further, it has been reported that according to a method of polymerizing an ethylenically unsaturated monomer having a carboxyl group in supercritical carbon dioxide, a polymer fine powder can be produced in a high yield and in a small number of steps ( For example, see Patent Document 2.) In addition, it has been reported that a polymer having high yield and high versatility can be efficiently produced by the method of polymerizing a polymerizable monomer in supercritical carbon dioxide in the presence of a non-polymerizing dispersant having a carboxyl group. (For example, see Patent Document 3).
JP-T 9-503798 JP 2001-151802 A JP 2002-128808 A

  However, the polymerization method according to Patent Document 1 has a problem that the yield of the obtained polymer is low and is not sufficient as a production method on an industrial scale. In addition, the polymer obtained by this method has difficulties in compatibility and adhesion with general-purpose plastics and inorganic / metal substrates due to the water and oil repellency of fluorine and silicon, and its use is limited. There was also a problem of end. Further, in this method, it is necessary to remove the surfactant remaining after the production of the polymer. As the removal method, for example, there is a method of washing the polymer using an organic solvent capable of dissolving the surfactant. However, it is not only disadvantageous in terms of cost, but also uses an organic solvent, so that there is a problem that it does not reduce the environmental burden.

  Moreover, all the polymers obtained by the polymerization method according to Patent Document 2 or 3 have a high glass transition temperature, and some have a glass transition temperature close to 100 ° C. Therefore, although these polymers are excellent in mechanical strength, there is a problem that toughness (for example, elasticity and impact absorption) is not sufficient. Therefore, when these polymers are used as a material for paints or molded articles, there is a problem that a coating film or molded article having excellent toughness cannot be obtained. Therefore, development of high molecular weight fine powder having excellent toughness, that is, having a low glass transition temperature has been demanded from the market.

  The problem to be solved by the present invention is to provide a method for producing a fine polymer powder having a glass transition temperature lower than that of the prior art. Furthermore, the environmental load is low, the process is simple, and the polymer is produced in a high yield. It is providing the method of manufacturing a fine powder.

The present inventors attempted to lower the glass transition temperature of the polymer fine powder obtained by reducing the amount of the ethylenically unsaturated monomer having a carboxyl group in the polymerization method according to Patent Document 2. It was.
However, in this case, the degree of polymerization of the resulting polymer is lowered, and physical properties such as toughness are still not sufficient.
Therefore, when a vinyl monomer having a specific functional group having a hydroxyl group-terminated terminal unit having a structural unit derived from alkylene glycol was used, the toughness could not be solved by using a vinyl monomer having a carboxyl group. It has been found that polymer fine powders having excellent physical properties such as can be produced.

  That is, this invention relates to the manufacturing method of the polymer fine powder characterized by polymerizing the vinyl monomer represented by the following general formula (I) in supercritical carbon dioxide.

（式中、Ｘは、水素原子又はメチル基を表す。Ｙは、下記一般式（ＩＩ）で表される構造単位を有し、且つ、末端が水酸基である構造を表す。）

(In the formula, X represents a hydrogen atom or a methyl group. Y represents a structure having a structural unit represented by the following general formula (II) and having a terminal hydroxyl group.)

（式中、ｍ及びｎは、それぞれ１以上の整数を表す。）

(In the formula, m and n each represent an integer of 1 or more.)

  In the method for producing a fine polymer powder of the present invention, X in the general formula (I) is preferably a methyl group.

  In the method for producing a fine polymer powder of the present invention, it is preferable that m in the general formula (II) is 2 and n is 4 to 20.

  In the method for producing a fine polymer powder of the present invention, it is preferable that m in the general formula (II) is 3 and n is 4 to 20.

  According to the method for producing a polymer fine powder of the present invention, a polymer fine powder having a low glass transition temperature and excellent toughness and high versatility can be produced. Furthermore, the environmental load is low, the process is simple, and the yield is high. Polymer fine powder can be produced.

The present invention is described in detail below.
The method for producing a fine polymer powder of the present invention is a method in which the vinyl monomer represented by the general formula (I) is polymerized in supercritical carbon dioxide. In the general formula (I), X represents a hydrogen atom or a methyl group. Y represents a structure having a structural unit represented by the general formula (II) and having a terminal hydroxyl group, and in the general formula (II), m and n each represents an integer of 1 or more. Represent.

  Here, supercritical carbon dioxide is a fluid in which carbon dioxide is heated and pressurized to the critical point (critical temperature 31 ° C., critical pressure 7.38 MPa) or higher and does not liquefy even when pressurized further. Carbon dioxide, usually having both gas and liquid properties.

  This supercritical carbon dioxide can be obtained by introducing commercially available carbon dioxide contained in a cylinder or the like into an apparatus for performing a polymerization reaction so that the temperature is higher than the critical temperature and the critical pressure. As such carbon dioxide, one having a purity of 99.9% or more is preferably used.

  The vinyl monomer used in the present invention is represented by the above general formula (I) (hereinafter referred to as “vinyl monomer (A)”). It is good also as a mixture which further contained this vinyl monomer (A) and arbitrary components.

  X which this vinyl monomer (A) has is a hydrogen atom or a methyl group, and preferably a methyl group.

  Moreover, Y which vinyl monomer (A) has has a structural unit represented by the said general formula (II), and the terminal is a hydroxyl group, for example, the functional group derived from polyalkylene glycol is mentioned. .

M in the general formula (II) represents the number of carbon atoms in the structural unit represented by the general formula (II), and is an integer of 1 or more. Among these, what is the range of 2-4 is preferable, and what is 2 or 3 is more preferable.
By using the vinyl monomer (A) having the structural unit represented by the general formula (II) having a carbon number in such a range, the polymer fine powder can be sufficiently dispersed in the supercritical carbon dioxide. . Examples of the structural unit represented by the general formula (II) include structures derived from polyalkylene glycol, and examples include structural units derived from ethylene glycol, propylene glycol, tetramethylene glycol, and the like.

N in the general formula (II) represents the number of repeating units of the structural unit represented by the general formula (II), and is an integer of 1 or more. Among these, it is preferable that it is the range of 3-30, and it is more preferable that it is the range of 4-20.
By using the vinyl monomer (A) having a repeating unit in such a range, the polymer fine powder can be sufficiently dispersed in supercritical carbon dioxide.

  Examples of the vinyl monomer (A) used in the present invention include 2-hydroxyethyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, hydroxypropyl (meth) acrylate, polypropylene glycol mono (meth) acrylate, poly (Ethylene glycol) -poly (propylene glycol) mono (meth) acrylate, poly (ethylene glycol) -poly (tetramethylene glycol) mono (meth) acrylate, poly (propylene glycol) -poly (tetramethylene glycol) mono (meth) An acrylate etc. are mentioned. These can be used alone or in combination of two or more. By polymerizing such a vinyl monomer (A), the glass transition temperature of the polymer can be lowered.

  Among the vinyl monomers (A), 2-hydroxyethyl methacrylate, polyethylene glycol monomethacrylate, hydroxypropyl methacrylate, polypropylene glycol monomethacrylate, poly (ethylene glycol) -poly (propylene glycol) monomethacrylate, poly (ethylene glycol) ) -Poly (tetramethylene glycol) monomethacrylate, poly (propyleneglycol) -poly (tetramethyleneglycol) monomethacrylate and other methacrylates are used because it is easy to produce high molecular weight fine powder in supercritical carbon dioxide. preferable.

  Y in the general formula (I) may have, for example, an alkyl group, a phenyl group, a carbonyl group, a ketone, an ether, an ester, or the like.

  Moreover, in this invention, vinyl monomers other than the said vinyl monomer (A) can be added within the range which achieves the objective of this invention.

  Examples of such vinyl monomers include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, and isobutyl (meth). (Meth) acrylic acid alkyl esters such as acrylate, sec-butyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate and hexadecyl (meth) acrylate Methoxypolyethylene glycol (meth) acrylate, methoxypolypropylene glycol (meth) acrylate, lauroxypolyethylene glycol (meth) acrylate, lauroxypolypropylene glycol Alkyl group-terminated polyalkylene glycol (meth) acrylates such as (meth) acrylate, nonylphenoxypolyethylene glycol (meth) acrylate, nonylphenoxypolypropylene glycol (meth) acrylate; styrene monomers such as styrene and α-methylstyrene; vinyl acetate, allyl vinyl Vinyl esters such as methyl vinyl ether and ethyl vinyl ether; p-vinyltoluene, acrylonitrile and the like. These can be used alone or in combination of two or more.

  The content of the vinyl monomer (A) used in the present invention depends on what is used, but it is preferably 10% by mass or more, and 20% by mass in the mixture containing the vinyl monomer (A). % Or more is more preferable. By adjusting to such a range, the polymer fine powder can be dispersed in the supercritical carbon dioxide, and a stable polymer fine powder can be produced.

  When the vinyl monomer (A) according to the present invention is polymerized in supercritical carbon dioxide, a solvent can be used as necessary. Such a solvent is not particularly limited as long as it has no reactivity with supercritical carbon dioxide, for example, water, lower alcohols such as methanol and ethanol, ketones such as acetone and methyl ethyl ketone, or diethyl ether and diisopropyl ether. Examples include ethers, nitriles such as acetonitrile, and aromatics such as benzene, toluene, and xylene. This solvent can be added in an amount of about 0.1 to 50 parts by mass with respect to 100 parts by mass of the mixture containing the vinyl monomer (A). Is preferred.

  In the method for producing a polymer fine powder of the present invention, a mixture containing a vinyl monomer (A) and carbon dioxide are added to a reaction vessel, and the carbon dioxide is heated and pressurized to a critical temperature and a critical pressure or higher. And a supercritical carbon dioxide solvent, and a mixture containing the vinyl monomer (A) is polymerized in this solvent.

  As a method for polymerizing the mixture containing the vinyl monomer (A), for example, a known polymerization method such as a radical polymerization method, a cationic polymerization method, or an anionic polymerization method can be used. Among these, it is preferable to use a radical polymerization method.

  This radical polymerization method is a method in which the double bond of the vinyl monomer (A) is cleaved by radicals generated from a polymerization initiator such as a peroxide or an azo compound to advance the polymerization.

  Examples of the polymerization initiator that can be used in the radical polymerization method include 2,2-azobisisobutyronitrile, 2,2-azobis (2,4-dimethylvaleronitrile), and 2,2-azobis (2-methyl). Azo initiators such as butyronitrile), t-butyl hydroperoxide, cumene hydroperoxide, t-butyl peroxyneodecanate, t-butyl peroxypivalate, t-hexyl peroxy-2-ethylhexanate, t-butyl Examples thereof include organic peroxides such as peroxy-2-ethylhexanate and t-butylperoxybenzoate. These can be used alone or in combination of two or more.

  Moreover, the usage-amount of these polymerization initiators becomes like this. Preferably it is 0.05-20 mass% with respect to the mixture containing a vinyl monomer (A), More preferably, it is 0.1-15 mass%. . By adjusting to such a range, the polymerization can be sufficiently advanced, and the unreacted polymerization initiator can be prevented from remaining in the polymer.

  On the other hand, the cationic polymerization method is a method in which polymerization is performed using an electrophilic initiator such as hydrochloric acid, sulfuric acid, and aromatic sulfonium salt as a polymerization initiator. The amount of these polymerization initiators used is preferably 0.05 to 20% by mass, more preferably 0.1 to 20% by mass with respect to the mixture containing the vinyl monomer (A), as in the radical polymerization method. 15% by mass. By adjusting to such a range, the polymerization can be sufficiently advanced, and the unreacted polymerization initiator can be prevented from remaining in the polymer.

  The anionic polymerization method is a method of polymerizing using a nucleophilic initiator such as an alkali metal or a Grignard reagent as a polymerization initiator. The amount of the polymerization initiator used is preferably 0.05 to 20% by mass, more preferably, based on the mixture containing the vinyl monomer (A), as in the radical polymerization method and the cationic polymerization method. 0.1 to 15% by mass. By adjusting to such a range, the polymerization can be sufficiently advanced, and the unreacted polymerization initiator can be prevented from remaining in the polymer.

  Moreover, it is preferable that it is 100-30000 mass parts with respect to 100 mass parts of mixtures containing a vinyl monomer (A), and the quantity of the carbon dioxide added to reaction container is 500-10000 mass parts. More preferred. By adjusting to such a range, the mixture containing the vinyl monomer (A) can be sufficiently dissolved in supercritical carbon dioxide, and the polymerization can be effectively advanced.

  The reaction temperature when producing the polymer fine powder is not particularly limited as long as it is equal to or higher than the critical temperature of carbon dioxide (31 ° C.), but is preferably 35 to 160 ° C., and preferably 40 to 100 ° C. More preferably, it is most preferable that it is 50-100 degreeC. By adjusting the reaction temperature to such a range, the polymerization initiator is easily decomposed by heat, and the polymerization reaction can be effectively advanced.

  Moreover, the pressure at the time of manufacturing the polymer fine powder is not particularly limited as long as it is higher than the critical pressure of carbon dioxide (7.38 MPa), but it is preferably 15 to 40 MPa. In addition, the polymerization time depends on the polymerization temperature and other conditions and cannot be determined generally, but it is preferably in the range of 2 to 48 hours.

  This polymerization reaction is preferably carried out while stirring the reaction system in a reaction vessel. As the stirring method, for example, it is preferable to use a well-known stirring apparatus so that the product does not precipitate. Specifically, for example, it is preferable to use a stirring device such as a magnetic stirrer and stir at a rotational speed of 50 to 2000 rpm.

  After the completion of this polymerization reaction, the temperature and pressure are lowered to discharge carbon dioxide, and the polymer fine powder is taken out from the reaction vessel. By using carbon dioxide as the solvent, the solvent can be easily discharged after completion of the polymerization reaction, so that the polymer fine powder as a polymer can be easily taken out from the reaction vessel. According to the production method of the present invention, polymer fine powder can be produced with a yield of 80% by mass or more.

  The polymer fine powder produced by the production method of the present invention has an average particle diameter of 1 to 50 μm and a number average molecular weight of 10,000 or more. The average particle size is a value obtained by observing with a scanning electron microscope and averaging the particle size (radius) of 100 polymer fine powders.

  The glass transition temperature of the polymer fine powder produced by the production method of the present invention is 0 ° C to 60 ° C. According to the production method of the present invention, a polymer fine powder having a low glass transition temperature in the above range can be produced, so that a polymer fine powder excellent in physical properties such as toughness can be obtained.

  The polymer fine powder obtained by the method for producing a polymer fine powder of the present invention can be suitably used as a material such as paint, ink, adhesive, molded product, cosmetic base material, and pharmaceutical.

  Hereinafter, the present invention will be described in more detail by way of examples. The present invention is not limited to the following examples.

[Example 1]
<Manufacture of polymer fine powder>
Polypropylene glycol monomethacrylate (“Blenmer PP-800” manufactured by NOF Corporation, degree of polymerization 13 of structural units derived from polypropylene glycol) (hereinafter referred to as “PP”) was placed in a 36 ml metal high-pressure polymerization vessel having a stirrer and a temperature measuring device. It was abbreviated as “−800”.) 6.011 g and 59.6 mg of 2,2-azobis (isobutyronitrile) were added.

Next, 29 g of carbon dioxide was injected into this container, and heated and pressurized quickly so that the temperature in the polymerization container was 65 ° C. and the pressure was 30.4 MPa. After reaching the predetermined temperature and pressure, the monomer was polymerized in 24 hours while stirring.
After completion of the polymerization, the temperature and pressure in the polymerization vessel were lowered, and carbon dioxide was discharged. White polymer fine powder was obtained in the container. The yield was 5.163 g (yield 85.9% by mass). The obtained polymer fine powder was evaluated by the following methods.

<Method for evaluating polymer fine powder>
(1) Particle size measurement method of polymer fine powder Observation was performed using a scanning electron microscope (Hitachi Scanning Microscope S-800), and the average particle size was obtained by averaging the particle sizes of 100 polymer fine powders. .

(2) Measurement of glass transition temperature (Tg) A differential scanning calorimeter (DSC: Seiko DSC220) was used and measured according to JIS K6900.

(3) Simple evaluation method of toughness 50 mg of polymer fine powder was uniformly placed on a slide glass, a cover glass was placed thereon, and a 20 g weight was loaded. Next, the slide glass was fixed under room temperature conditions, and the cover glass was moved 3 cm × 10 times back and forth together with the weight to rub against the polymer fine powder. At this time, the polymer fine powder was broken, and its average particle size was reduced when observed with a scanning electron microscope. The toughness was evaluated as follows from the proportion of the average particle size changed.
○: The magnitude of the change in the average particle diameter before and after the simple toughness evaluation is within 5%.
(Triangle | delta): The magnitude | size to which the average particle diameter changed before and after the toughness simple evaluation is 5 to 20%.
X: The magnitude | size which the average particle diameter changed before and after simple toughness evaluation is 20% or more.

In FIG. 1, the photograph of the observation result of the polymer fine powder of Example 1 by a scanning electron microscope is shown. From FIG. 1, it was confirmed that the polymer fine powder had an average particle diameter of 30 μm.
Moreover, it was 37 degreeC when the glass transition temperature of this polymer fine powder was measured. Table 1 shows the glass transition temperature and the results of toughness evaluation.

[Example 2]
Example 1 Polypropylene glycol monomethacrylate (Nippon Yushi “Blenmer PP-500”, degree of polymerization of polypropylene glycol-derived structural unit 9) 5.445 g and 2,2-azobis (isobutyronitrile) 89.4 mg Polymerization was conducted in the same manner as described above. White polymer fine powder was obtained in the polymerization vessel, and the yield was 4.667 g (yield 85.7 mass%).
The obtained polymer fine powder was evaluated in the same manner as in Example 1. Observation with a scanning electron microscope confirmed that the polymer fine powder had an average particle size of 24 μm. The polymer fine powder had a glass transition temperature of 23 ° C. Table 1 shows the glass transition temperature and the results of toughness evaluation.

[Example 3]
Example 1 9.273 g of polyethylene glycol monomethacrylate (Nippon Yushi “Blenmer PE-350”, degree of polymerization 8 of structural units derived from polyethylene glycol) and 90.6 mg of 2,2-azobis (isobutyronitrile) Polymerization was conducted in the same manner as described above. White polymer fine powder was obtained in the polymerization vessel, and the yield was 8.548 g (yield 92.2% by mass).
The obtained polymer fine powder was evaluated in the same manner as in Example 1. Observation with a scanning electron microscope confirmed that the polymer fine powder had an average particle diameter of 31 μm. The polymer fine powder had a glass transition temperature of 14 ° C. Table 1 shows the glass transition temperature and the results of toughness evaluation.

[Example 4]
In the same manner as in Example 1, 4.486 g of PP-800, 1.247 g of methyl methacrylate, and 89.4 mg of 2,2-azobis (isobutyronitrile) were polymerized. White polymer fine powder was obtained in the polymerization vessel, and the yield was 5.131 g (yield 89.5% by mass).
The obtained polymer fine powder was evaluated in the same manner as in Example 1. Observation with a scanning electron microscope confirmed that the polymer fine powder had an average particle diameter of 27 μm. The glass transition temperature of this polymer fine powder was 42 ° C. Table 1 shows the glass transition temperature and the results of toughness evaluation.

[Example 5]
PP-800 (4.637 g), polyethylene glycol monomethacrylate having a methoxy group at one end (“MPEM400” manufactured by Daiichi Kogyo Seiyaku) (hereinafter abbreviated as “MPEM400”) (2.208 g), 2,2- 90.6 mg of azobis (isobutyronitrile) was polymerized in the same manner as in Example 1. White polymer fine powder was obtained in the polymerization vessel, and the yield was 6.304 g (yield 92.1% by mass).
The obtained polymer fine powder was evaluated in the same manner as in Example 1. In FIG. 2, the photograph of the observation result of the polymer fine powder of Example 5 by a scanning electron microscope is shown. It was confirmed that the polymer fine powder had an average particle diameter of 33 μm. The polymer fine powder had a glass transition temperature of 13 ° C. Table 1 shows the glass transition temperature and the results of toughness evaluation.

[Comparative Example 1]
100 g of methyl ethyl ketone (hereinafter abbreviated as “MEK”) is kept at 80 ° C. in a nitrogen stream and stirred, and 100 g of PP-800 and a polymerization initiator (“V-59” manufactured by Wako Pure Chemical Industries, Ltd.) A mixture consisting of 6 g was added dropwise over 2 hours. After completion of the dropwise addition, 0.5 g of a polymerization initiator (“V-59” manufactured by Wako Pure Chemical Industries, Ltd.) was added every 3 hours and stirred at 80 ° C. for 16 hours.
In this way, an MEK solution of an acrylic resin having a nonvolatile content of 50% by mass was obtained.
When the MEK solution of the obtained acrylic resin was dried with a hot air drier to remove MEK, a liquid resin was obtained and it was impossible to make it into powder.

[Comparative Example 2]
Polyethylene glycol monomethacrylate having a methoxy group at one end (MPEM400, molecular weight 400, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 5.696 g and 2,2 in a 36-ml metal high-pressure polymerization vessel having a stirrer and a temperature measuring device -116.9 mg of azobis (isobutyronitrile) were added.
Next, 29 g of carbon dioxide was injected into this container, and heated and pressurized quickly so that the temperature in the polymerization container was 65 ° C. and the pressure was 300 kg / cm ² . After reaching the predetermined temperature and pressure, the monomer was polymerized in 24 hours while stirring.
After completion of the polymerization, the temperature and pressure in the polymerization vessel were lowered, and then carbon dioxide was discharged. Solid content was not seen in this container, but only liquid oligomer was obtained, and it was confirmed that the polymerization reaction was not completed.

[Comparative Example 3]
In the same manner as in Example 1, 3.361 g of methyl methacrylate and 0.279 g of methacrylic acid and 302.0 mg of 2,2-azobis (isobutyronitrile) were polymerized. White polymer fine powder was obtained in the polymerization vessel, and the yield was 3.629 g (yield 99.7 mass%).
The obtained polymer fine powder was evaluated in the same manner as in Example 1. Observation with a scanning electron microscope confirmed that the polymer fine powder had an average particle diameter of 15 μm. The polymer fine powder had a glass transition temperature of 108 ° C. Table 1 shows the glass transition temperature and the results of toughness evaluation.

  When Examples 1-5 are compared with Comparative Examples 1-3, Examples 1-5 are polymer fine powders having a uniform average particle diameter, and have a glass transition temperature of 50 ° C. or less and excellent toughness. Met. On the other hand, polymer fine powders were not obtained in Comparative Examples 1 and 2, and those of Comparative Example 3 had a high glass transition temperature of 100 ° C. or higher and poor toughness.

  From the above, according to the present invention, it was confirmed that a polymer fine powder having a low glass transition temperature, excellent toughness, and uniform average particle diameter can be produced in a simple process with a high yield.

The photograph which observed the polymer fine powder obtained in Example 1 with the scanning electron microscope is shown. The photograph which observed the polymer fine powder obtained in Example 5 with the scanning electron microscope is shown.

Claims (4)

The manufacturing method of the polymer fine powder characterized by polymerizing the vinyl monomer represented by the following general formula (I) in supercritical carbon dioxide.

(In the formula, X represents a hydrogen atom or a methyl group. Y represents a structure having a structural unit represented by the following general formula (II) and having a terminal hydroxyl group.)

(In the formula, m and n each represent an integer of 1 or more.)   The method for producing a fine polymer powder according to claim 1, wherein X in the general formula (I) is a methyl group.   3. The method for producing fine polymer powder according to claim 1, wherein m in the general formula (II) is 2 and n is 4 to 20. The method for producing fine polymer powder according to claim 1 or 2, wherein m in the general formula (II) is 3 and n is 4 to 20.

Images