JP5583446B2 - Resin powder and method for producing the same - Google Patents

Description

  The present invention relates to a resin powder and a method for producing the same.

  In recent years, development of polymer fine particles has been activated, and it is widely used in various industrial applications. Among them, fine polymer particles with a spherical particle shape and narrow particle size distribution are slipperiness imparting agents, toners, matting agents for paints, additives for light diffusion, low density due to their good processability, fluidity and surface properties. Anti-blocking material for packaging materials made of polyethylene, filters, separation membranes, dispersants, powder coatings, resin modifiers, coating agents, insulating fillers, crystal nucleating agents, chromatographic fillers and carriers for immunodiagnostic reagents It is widely used for such applications.

  These polymer particles have a wide variety of materials such as acrylic resin, styrene resin, melamine resin, and polyolefin. However, because of their high crystallinity, high melting point, and high chemical stability, polyolefin resin particles are Attention has been paid. Polyolefin resin fine particles have features such as water resistance, oil resistance, chemical resistance and biosafety that are not found in other materials, and various new materials and new applications have been devised and put to practical use. It has become.

  For example, polyethylene fine particles, polypropylene particles, and those with surface modification thereof are used as column fillers for high-efficiency separation of chemical and biological materials, and as adsorbents and catalyst carriers having a high specific surface area. be able to. In addition, it can be used as a carrier that is responsible for the delivery and release of drugs, etc., a spraying agent for uniformly dispersing fine particles with poor dispersibility, and a safety that provides a good touch effect on the skin as a cosmetic material It is used for highly fine particulate materials. Other materials include separators for lithium batteries and lithium ion secondary batteries, optical filter members with functions such as light diffusion, reflection, and antireflection, high performance binders for sintered porous bodies such as ceramics, and breathable films. Applications for new functional materials such as pore-forming materials, carriers for immobilizing immunochemically active substances, and fine pore / high specific surface area sintered filters are being actively studied.

  Polyolefin-based resins are basically composed of only carbon and hydrogen atoms, and they are lightweight and inexpensive, and have excellent physical properties and processability, but they are different from other materials such as metals and other resins. Poor affinity, adhesion and reactivity. Therefore, when using fine particles composed of polyolefin resin having such characteristics for the above various applications, polar groups or polar segments excellent in affinity, adhesion, and reactivity with other members are used. It is necessary to introduce into the surface of fine particles.

  Examples of the polyolefin fine particles having polar groups and polar segments introduced on the surface include, for example, those obtained by introducing a polymer segment of n-butyl acrylate on the surface of EVA as disclosed in Patent Document 1, and Patent Document 2 Examples include polar group-containing high molecular weight polyolefin particles as disclosed, but in the methods described in these documents, the bonding force between the core portion and the shell layer is relatively weak, and depending on the application, due to separation of both The predetermined function may not be expressed.

  On the other hand, as a method for introducing a polar segment into polyolefin, a method using a combination of halogenated polyolefin and living radical polymerization is disclosed (Patent Document 3). In the polymer produced by this method, since the polyolefin segment and the polar segment are chemically bonded by a carbon-carbon bond, the above-described problem of separation between the core portion and the shell layer cannot occur. However, it is difficult to produce a polymer having a core-shell structure only by using the method described in Patent Document 3, and there is no example of producing core-shell particles by this method.

Patent Documents 4 to 8 include
Coating with a graft polymer on the surface of a sheet by introducing a halogen-containing organic group into the polyolefin resin in advance, molding a sheet using this polyolefin resin, and then surface graft-polymerizing the sheet surface with halogen atoms as an initiation group A method of forming a layer;
A method of forming a coating layer made of a graft polymer on a sheet surface by directly introducing a halogen-containing organic group into a sheet made of a polyolefin resin and then performing surface graft polymerization using a halogen atom on the sheet surface as an initiation group is disclosed. Yes.

JP 2006-182925 A Japanese Patent Laid-Open No. 2007-161896 WO2006 / 088197 pamphlet JP 2008-37950 A JP 2008-63532 A JP 2008-63533 A JP 2008-63534 A JP 2008-95083 A

  However, the prior arts described in the above documents 4 to 8 have room for improvement in the following points.

  In the method of molding a polyolefin resin into which a halogen-containing organic group has been introduced in advance and then performing surface graft polymerization using a halogen atom on the surface of the molded body as an initiation group, since the halogen atom is contained inside the molded body, The property could be impaired. Furthermore, in the graft polymerization, the monomer or the monomer solution reaches the halogen atoms existing in the surface layer by infiltration, and the graft polymerization proceeds. Therefore, it is difficult to form a uniform coating layer only on the very outermost surface.

  In the method of directly halogenating the surface of the molded body and then graft polymerization, the inside of the surface layer is brominated because the molded body is immersed in a halogenating agent solution or a liquid halogenating agent in the halogenation process. In subsequent graft polymerization, graft polymerization proceeds from the inside of the surface layer due to infiltration of the monomer or monomer solution, and it is difficult to form a uniform coating layer only on the very outermost surface.

  In particular, when the fine particles are used as the base material, the above-described problems are manifested because the specific surface area is large, and only the outermost surface cannot be efficiently graft-polymerized, so that desired characteristics may not be obtained. Further, when the fine particles are used as the base material, the specific surface area becomes large, so that it is necessary to graft polymerize a sufficient amount of monomer to form the coating layer and obtain the desired characteristics, thus maintaining the characteristics of the base material. In addition, when expensive monomers are used, there is an economical problem.

The present invention can be described below.
(1) In a coated resin fine particle having a coating layer made of a polymer obtained by polymerizing a monomer on the surface of a resin fine particle, the resin fine particle surface and the polymer are chemically bonded by a carbon-carbon bond. A resin powder comprising coated resin fine particles, wherein the thickness of the coating layer is greater than 0 and 60 nm or less, and the mass of the polymer per unit surface area of the resin fine particles is ² to 150 mg / m ^2. Body ,
After the surface of the resin fine particles is plasma-treated to form dangling bonds, a polymerization initiating group is bonded to the dangling bonds by contacting a reactive gas, and a monomer is surface-grafted from the polymerization initiating group. A resin powder comprising coated resin fine particles provided with a coating layer comprising a polymer obtained in this manner .

(2) In the coated resin fine particles provided with a coating layer made of a polymer obtained by polymerizing monomers on the surface of the resin fine particles,
The surface of the resin fine particles and the polymer are chemically bonded by a carbon-carbon bond, and the thickness of the coating layer is greater than 0 and 60 nm or less, and the mass of the polymer per unit surface area of the resin fine particles Is a resin powder composed of coated resin fine particles, characterized in that is ² to 150 mg / m ² ,
A coating layer comprising a polymer obtained by bonding the polymerization initiating group by subjecting the surface of the resin fine particles to plasma treatment in a gas atmosphere containing a reactive gas, and then subjecting the monomer to surface graft polymerization from the polymerization initiating group. A resin powder comprising coated resin fine particles .

(3) The resin powder according to (1) or (2), wherein the plasma treatment is performed under a pressure of 3 × 10 ⁴ Pa or more and 15 × 10 ⁴ Pa or less.

(4) Any one of (1) to (3), wherein the reactive gas is a gas containing a halogen atom, and the polymerization initiating group is a halogen atom or an atomic group containing a halogen atom. The resin powder described in 1 .

(5) The resin powder according to any one of (1) to (4), wherein the surface graft polymerization is atom transfer radical polymerization .

(6) The resin powder as described in any one of (1) to (5), wherein the mass of the polymer per unit surface area of the resin fine particles is ² to 100 mg / m ² .

(7) The resin powder according to any one of (1) to (6), wherein the coating resin fine particles contain 0.1% by weight or more of the polymer .

(8) The resin powder according to any one of (1) to (7), wherein the coated resin fine particles have an average particle diameter of 1 to 100 μm .
(9) The resin powder according to any one of (1) to (8), wherein the resin fine particles are made of polyolefin .

(1 0) the monomer, the carbon - resin powder according to any one of to, characterized in that one or more selected from organic compounds having a carbon-carbon unsaturated bond (1) - (9).

(1 1 ) Plasma treatment of resin powder to form unbonded hands on the surface of resin fine particles constituting the resin powder, and contact of reactive gas with resin fine particles on which the unbonded hands are formed And bonding the atoms or atomic groups composed of the reactive gas to the dangling bonds, and surface graft polymerizing the monomer using the atoms or atomic groups as a polymerization initiating group. Forming a coating layer made of a polymer to obtain coated resin fine particles, and a method for producing a resin powder comprising coated resin fine particles.

(1 2) coupling the resin powder consisting of resin particles, by plasma treatment in a gas atmosphere containing a reactive gas, a pre Bark atom or atomic group composed of the reactive gas on the surface of the fat particles A process of
A step by the monomers to surface graft polymerization, which forms a coating layer comprising a polymer in the resin fine particle surface to obtain a coating resin particles as a polymerization initiator based on the atom or atomic group,
A method for producing a resin powder comprising coated resin fine particles.

(1 3 ) The method for producing a resin powder according to (1 1 ) or (1 2 ), wherein the plasma treatment is performed at 3 × 10 ⁴ Pa or more and 15 × 10 ⁴ Pa or less.
(1 4) the surface graft polymerization method for producing a resin powder according to any one of, wherein the atom transfer radical polymerization (1 1) - (1 3).
(1 5) the monomer, the carbon - characterized in that it is one or more selected from organic compounds having a carbon-carbon unsaturated bond (1 1) resin powder according to any one of - (1 4) Manufacturing method.

(1 6) the reactive gas, the production method of the resin powder according to any one of to, characterized in that a gas containing a halogen atom (1 1) - (1 5).
(1 7) the resin fine particles is characterized in that it consists of polyolefin (1 1) to the production method of the resin powder according to any one of (1 6).

(1 8 ) (1 1 ) to (1), wherein the resin powder made of the resin fine particles is dropped in a discharge chamber for generating plasma, and plasma treatment is performed while the resin powder is falling. 7 ) The method for producing a resin powder according to any one of the above.

  In the core-shell type particle according to the present invention, the coating layer and the base particle are chemically bonded by a carbon-carbon bond, so that the processability, chemical resistance, electrical property, mechanical property, slidability, Excellent wear and impact resistance, and excellent adhesion and affinity with other components. At the same time, the coating layer is formed as a uniform thin film on the outermost surface of the base material particles, and does not impair the original properties of the base material. This also has an advantageous effect.

It is a schematic diagram which shows the manufacturing apparatus concerning embodiment of this invention. It is sectional drawing along the direction orthogonal to the longitudinal direction of the discharge tube of a manufacturing apparatus. It is a schematic diagram which shows the manufacturing apparatus concerning the modification of this invention. FIG. 4 shows the observation result of the cross section of the core-shell fine particles obtained in Example 1 with a transmission electron microscope. FIG. 5 shows the observation result of the cross section of the core-shell fine particles obtained in Example 2 with a transmission electron microscope. FIG. 6 shows the observation result of the cross section of the core-shell fine particles obtained in Example 3 with a transmission electron microscope. FIG. 7 shows the observation result of the cross section of the core-shell fine particles obtained in Example 4 with a transmission electron microscope. FIG. 8 shows the observation result of the cross section of the core-shell fine particles obtained in Example 5 with a transmission electron microscope. FIG. 9 shows the observation result of the cross section of the core-shell fine particles obtained in Example 6 with a transmission electron microscope. FIG. 10 shows the observation result of the cross section of the fine particles obtained in Comparative Example 1 with a transmission electron microscope. FIG. 11 shows the observation result of the cross section of the fine particles obtained in Comparative Example 2 with a transmission electron microscope. FIG. 12 is a graph plotting the results of the dispersibility evaluation. FIG. 13 is a graph plotting the results of dispersibility evaluation and the correlation between the dispersibility and the content of the graft polymer.

The resin powder according to the present invention will be specifically described below.
The resin powder of the present embodiment is made of coated resin fine particles that are core-shell fine particles. The coated resin fine particles were obtained by surface graft polymerization of a monomer having at least one carbon-carbon unsaturated bond from the polymerization initiating group on the surface of the resin fine particles (core particles) having a polymerization initiating group bonded to the surface. A coating layer (shell layer) made of a graft polymer is provided.

  In the resin powder of this embodiment, the resin present on the surface of the resin fine particles and the graft polymer are chemically and firmly bonded by carbon-carbon bonds, and the peeling of the coating layer from the resin fine particles is suppressed. ing.

  The coated resin fine particles contained in the resin powder of the present embodiment have an average particle diameter of 1 to 100 μm, preferably 3 to 50 μm. The average particle diameter can be measured by a laser diffraction scattering method.

  Moreover, the film thickness of a coating layer is larger than 0 and 60 nm or less, Preferably it is 5-30 nm. The film thickness of the coating layer can be measured with a transmission electron microscope (TEM). Further, “greater than 0” means a film thickness that can be observed with a transmission electron microscope, and in this embodiment is 2 nm or more. Since the surface of the resin fine particles is uniformly coated with the above film thickness, only the surface properties can be changed without impairing the properties of the resin fine particles as a bulk, and the desired properties can be obtained by the coating layer. .

Furthermore, the mass of the graft polymer per unit surface area of the resin fine particles is ² to 150 mg / m ² , preferably ² to 130 mg / m ² , more preferably ^{2 to} 100 mg / m ² , and still more preferably 4 to 70 mg / m ² . ² and even more preferably 4-50 mg / m ² . The content of the graft polymer is 0.1% by weight or more, preferably 0.3% by weight or more, more preferably 2% by weight or more, when the resin powder composed of the coated resin fine particles is 100% by weight. can do. The upper limit value can be 10% by weight or less, preferably 5% by weight or less, from the viewpoint of maintaining the properties of the substrate and exhibiting an economically advantageous effect.

  Since the film thickness of the coating layer and the mass of the graft polymer per unit surface area of the resin fine particles are both in the above range, even with resin fine particles having a large specific surface area, a uniform coating layer can be efficiently formed on the particle surface. The desired properties of the coating layer, such as workability, chemical resistance, electrical properties, mechanical properties, slidability, wear resistance, impact resistance, adhesion and affinity with other members, etc. Can be obtained. Furthermore, from the viewpoint of the above effect, it is preferable that the film thickness of the coating layer, the mass of the graft polymer per unit surface area of the resin fine particles, and the content of the graft polymer are all in the above range. Further, from the viewpoint of the above effect, it is more preferable that the coating layer is provided on the entire particle surface.

  Examples of the resin constituting the resin fine particles include polyethylene resins such as low density polyethylene, linear low density polyethylene, high density polyethylene, and ultrahigh molecular weight polyethylene; polyolefin resins such as polypropylene resin; polyester resins such as polyethylene terephthalate; polyphenylene ether resin Alicyclic hydrocarbon resin; thermoplastic polyimide resin; polyamideimide resin; polyesterimide resin; polystyrene resin such as polystyrene, acrylonitrile / butadiene / styrene copolymer (ABS resin); polyamide resin; polyvinyl acetal resin; Polyvinyl acetate resin; polyvinyl chloride resin, poly (meth) acrylic acid ester resin such as polymethyl methacrylate; polyetherimide resin; thermoplastic polybenzimi Tetrazole resins. One or more of these can be selected and used.

  Also, epoxy resin, curable modified polyphenylene ether resin, curable polyimide resin, silicon resin, benzoxazine resin, melanin resin, urea resin, allyl resin, phenol resin, unsaturated polyester resin, bismaleimide triazine resin, alkyd resin, furan Curable resins such as resins, polyurethane resins, and aniline resins can also be used.

  In the present embodiment, it is preferable to use a polyolefin resin, and it is more preferable to use a polyethylene resin.

  The coating layer of the coated resin fine particles constituting the resin powder according to the present invention is composed of a homopolymer or copolymer of a monomer having at least one carbon-carbon unsaturated bond.

  Specific examples of the monomer used in the present invention include (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, (meth) acrylic acid-n-propyl, isopropyl (meth) acrylate, (meth ) Acrylic acid-n-butyl, (meth) acrylic acid isobutyl, (meth) acrylic acid-tert-butyl, (meth) acrylic acid-n-pentyl, (meth) acrylic acid-n-hexyl, (meth) acrylic acid Cyclohexyl, (meth) acrylic acid-n-heptyl, (meth) acrylic acid-n-octyl, (meth) acrylic acid-2-ethylhexyl, (meth) acrylic acid nonyl, (meth) acrylic acid decyl, (meth) acrylic Dodecyl acid, phenyl (meth) acrylate, toluyl (meth) acrylate, benzyl (meth) acrylate, (meth) acrylic acid 2-methoxyethyl oxalate, 3-methoxybutyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, stearyl (meth) acrylate, (meth ) Glycidyl acrylate, 2-aminoethyl (meth) acrylate, 2- (dimethylamino) ethyl (meth) acrylate, γ- (methacryloyloxypropyl) trimethoxysilane, ethylene oxide adduct of (meth) acrylic acid, (Meth) acrylic acid trifluoromethyl methyl, (meth) acrylic acid 2-trifluoromethyl ethyl, (meth) acrylic acid 2-perfluoroethyl ethyl, (meth) acrylic acid 2-perfluoroethyl-2-perfluorobutyl Ethyl, (meth) acrylic acid 2-perfluoroethyl, (meth) acrylic Perfluoromethyl oxalate, diperfluoromethyl methyl (meth) acrylate, 2-perfluoromethyl-2-perfluoroethyl methyl (meth) acrylate, 2-perfluorohexyl ethyl (meth) acrylate, (meth) (Meth) acrylic monomers such as 2-perfluorodecylethyl acrylate and 2-perfluorohexadecylethyl (meth) acrylate, styrene, vinyltoluene, α-methylstyrene, chlorostyrene, styrenesulfonic acid and salts thereof Styrenic monomers such as fluorinated vinyl monomers such as perfluoroethylene, perfluoropropylene, vinylidene fluoride, silicon-containing vinyl monomers such as vinyltrimethoxysilane and vinyltriethoxysilane, maleic anhydride, maleic acid, maleic acid Monoalkyl Steal and dialkyl esters, fumaric acid, monoalkyl and dialkyl esters of fumaric acid, maleimide, methylmaleimide, ethylmaleimide, propylmaleimide, butylmaleimide, hexylmaleimide, octylmaleimide, dodecylmaleimide, stearylmaleimide, phenylmaleimide, cyclohexylmaleimide, etc. Maleimide monomers, nitrile group-containing vinyl monomers such as acrylonitrile, methacrylonitrile, (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-propyl (meth) acrylamide, N- Amide group-containing vinyl such as isopropyl (meth) acrylamide, N-butyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, etc. Monomers, vinyl acetate, vinyl propionate, vinyl pivalate, vinyl benzoate, vinyl cinnamate and other vinyl ester monomers, ethylene, propylene, butene and other olefin monomers, butadiene, isoprene and other diene monomers, chloride Examples thereof include vinyl, vinylidene chloride, allyl chloride, allyl alcohol, and the like, and further, a macromonomer having a carbon-carbon unsaturated bond such as an acroyl group, a methacryloyl group or a styryl group at the terminal and having a molecular weight of 100 to 100,000. The said monomer used in this embodiment can be used 1 type or in combination of 2 or more types from these.

  The graft polymer used in the present embodiment is obtained by (co) polymerizing one or more monomers selected from (meth) acrylic acid and derivatives thereof, (meth) acrylonitrile, styrene and derivatives thereof. Polymers are preferred, (meth) acrylic acid esters, styrene, (meth) acrylamides, (meth) acrylonitrile, (meth) acrylic acid homopolymers and copolymers are more preferred, especially methyl methacrylate, styrene, acrylic A homopolymer of methyl acrylate, acrylonitrile, butyl acrylate, acrylamide or a copolymer containing these as main monomers is preferred.

  In addition, when the coating layer made of a graft polymer is used in applications where affinity with other solvents or affinity with other resins is important, the polymer is insoluble in organic solvents, or the surface becomes non-smooth. Polymers are not preferred.

  Below, the manufacturing method of the resin powder which concerns on this invention is demonstrated in detail.

  The resin powder of the present embodiment is made of coated resin fine particles that are core-shell fine particles. The coated resin fine particles were obtained by surface graft polymerization of a monomer having at least one carbon-carbon unsaturated bond from the polymerization initiating group on the surface of the resin fine particles (core particles) having a polymerization initiating group bonded to the surface. A coating layer (shell layer) made of a graft polymer is provided. As a method for producing such a resin powder, for example, a method of sequentially performing the following steps (A) and (B) can be mentioned.

Step (A): A step of introducing a polymerization initiating group into the surface of resin fine particles by passing a resin powder made of resin fine particles through a discharge chamber that generates plasma, and in step (A) in a solvent. A step of forming a coating layer made of a graft polymer on the surface of the resin fine particles by bringing a monomer into contact with the surface of the obtained resin fine particles and performing graft polymerization from the polymerization initiating group.

<Process (A)>
Hereafter, the said process (A) is demonstrated based on drawing. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate.

In the present embodiment, the following two methods can be used as a method for bonding the polymerization initiating group to the surface of the resin fine particles.
Method (1): A method in which the surface of the resin fine particles is subjected to plasma treatment under an inert gas to form dangling bonds on the surface of the resin fine particles and then contacted with a reactive gas.
Method (2): A method in which the surface of the resin fine particles is directly plasma-treated in an atmosphere containing a reactive gas.
The layer affected by the plasma treatment is in the range of several tens of angstroms deep from the surface of the resin fine particles. By using the above method, the polymerization initiating group is introduced only on the outermost surface without impairing the original properties of the resin fine particles. can do. Furthermore, since graft polymerization is performed from the polymerization initiating group introduced on the outermost surface, the resulting graft polymer can efficiently coat the surface of the resin fine particles with a uniform thin film. For this reason, the resin powder containing the coated resin fine particles of the present embodiment efficiently develops desired characteristics of the coating layer while maintaining the original characteristics of the resin fine particles.

The plasma in this embodiment is generated in a pressure state of 3 × 10 ⁴ Pa or more and 15 × 10 ⁴ Pa or less (so-called atmospheric pressure plasma).
The low-pressure plasma used in many industrial plasma processes requires an exhaust system that can obtain a high degree of vacuum, but when using atmospheric pressure plasma, the exhaust system as described above is not required, so a stable process is required. Can process the powder.

The polymerization initiating group used in the present embodiment is not particularly limited as long as it can initiate the graft polymerization of the monomer, but is preferably a halogen atom or an atomic group containing a halogen atom that serves as an initiating group for atom transfer radical polymerization.
The halogen atom is selected from fluorine, chlorine, bromine or iodine, and may be a combination thereof. In the present invention, it is particularly preferable to use bromine.

  As the reactive gas, those containing the above halogen atoms or halogen-containing atomic groups are preferable, and chlorine gas, chloromethane, dichloromethane, trichloromethane, carbon tetrachloride, bromine gas, monobromomethane, dibromomethane, and trichloromethane are more preferable. This is preferable in that the vapor pressure in the vicinity of room temperature is low and vaporization is easy. In the present invention, it is particularly preferable to use bromine gas or tribromomethane.

  The inert gas described in the method (1) is a rare gas, and it is desirable to use helium or argon from the viewpoint of a low breakdown voltage at atmospheric pressure.

  The atmosphere containing the reactive gas described in the method (2) is a mixture of the reactive gas and the inert gas.

  Furthermore, with reference to FIG. 1, the manufacturing method of the resin fine particle by which the surface was processed with the reactive gas is demonstrated based on drawing. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate.

  First, with reference to FIG. 1, an outline of a manufacturing apparatus 1A used for manufacturing resin fine particles whose surface is treated with a reactive gas will be described.

The manufacturing apparatus 1A is an apparatus for plasma processing the powder P1.
In the present embodiment, the manufacturing apparatus 1 </ b> A is an apparatus for manufacturing a powder P <b> 2 containing resin fine particles whose surface is treated with a reactive gas. In the present embodiment, an apparatus for producing halogenated powder P2 will be described as an example. The manufacturing apparatus 1A includes a first electrode 231 and a second electrode 232 for generating plasma, and a powder supply unit 3 that supplies the powder P1 between the first electrode 231 and the second electrode 232. And halogenating means 4 for halogenating the surface of the resin fine particles treated with the plasma generated between the first electrode 231 and the second electrode 232.

  The halogenating means 4 includes a container (reaction container) 43 to which the plasma-treated powder P1 is supplied, and a gas supply unit 44 for supplying a gas containing halogen atoms into the container 43.

  Next, the manufacturing apparatus 1A will be described in detail with reference to FIG. 1 and FIG. FIG. 2 is a cross-sectional view of the discharge tube 2.

The manufacturing apparatus 1 </ b> A includes a discharge tube 2, a powder supply unit 3, and a halogenating unit 4.
The discharge tube 2 is composed of a triple tube arranged such that its longitudinal direction is along the vertical direction. Specifically, as shown in FIG. 2, the discharge tube 2 includes a first tube portion 201, a second tube portion 202 provided so as to surround the first tube portion 201, and the second tube portion 201. And a third cylindrical portion 203 provided so as to surround the cylindrical portion 202.

  A first electrode 231 is disposed inside the first tube portion 201. The first electrode 231 has a cylindrical shape and is fixed to the inner surface of the first tube portion 201. Electric power supplied from the high frequency power supply 25 is applied to the first electrode 231.

  A supply pipe 204 for supplying a cooling medium (for example, a liquid such as water) to the inside of the first cylinder part 201 is disposed inside the first cylinder part 201. The cooling medium is supplied from the supply pipe 204, passes between the first cylindrical portion 201 and the outer surface of the supply pipe 204, and cools the first electrode 231. Thereafter, the gas is discharged from a discharge pipe 205 provided at the upper end of the first cylindrical portion 201.

  The second cylinder part 202 is provided so as to surround the first cylinder part 201. A second electrode 232 is disposed on the outer surface side of the second cylindrical portion 202. Specifically, the second electrode 232 is attached to the outer surface of the second cylindrical portion 202.

  The second electrode 232 is helically fixed to the outer surface of the second cylindrical portion 202. The second electrode 232 is grounded. The second electrode 232 is disposed to face the first electrode 231, and a space sandwiched between the first electrode 231 and the second electrode 232 becomes a discharge chamber (discharge space) 2 </ b> A. Specifically, the discharge chamber 2 </ b> A is formed between the outer surface of the first tube portion 201 and the inner surface of the second tube portion 202.

  The third cylinder portion 203 is provided so as to surround the second cylinder portion 202. The second cylindrical portion 202 has flange portions 202A and 202B formed at the upper end portion and the lower end portion, and the third cylindrical portion 203 is disposed so as to be sandwiched between the flange portions 202A and 202B.

  A structure in which a cooling medium (for example, a liquid such as water) is supplied between the inner surface of the third cylindrical portion 203 and the outer surface of the second cylindrical portion 202, and the second electrode 232 is cooled by the cooling medium. It has become. Specifically, a supply pipe 206 for supplying a cooling medium is connected to the lower end part of the third cylinder part 203, and a discharge pipe 207 for discharging the cooling medium is connected to the upper end part of the third cylinder part 203. ing. The cooling medium flows from the bottom to the top.

A powder supply unit 3 for supplying the powder P1 into the discharge tube 2 is connected to the discharge tube 2 as described above.
The powder supply unit 3 supplies the powder P1 between the first electrode 231 and the second electrode 232, that is, between the outer surface of the first cylindrical part 201 and the inner surface of the second cylindrical part 202. To supply.

  Here, the powder P1 includes resin fine particles and is, for example, a polyolefin resin such as polyethylene.

The powder P1 is preferably composed of fine particles, and the fine particles preferably have an average particle size of 3 μm or more and 100 μm or less. The average particle diameter (d ₅₀ ) is measured by a laser diffraction scattering method (a method similar to the Cv value measurement method described later). By using the powder having such a particle diameter, it is possible to adjust the falling speed of the powder P1 (time for passing through the plasma) and to easily perform the plasma treatment on the powder P1.

Furthermore, the powder P1 preferably has a particle size distribution of 30% or less in terms of CV value.
In this way, by using the powder P1 having a narrow particle size distribution, the falling speed of the powder P1 can be made uniform, and the powder P1 can be reliably plasma-treated.

Here, the CV value is expressed by standard deviation ÷ particle diameter average value × 100, and can be measured by a laser diffraction scattering method. Specifically, the standard deviation is calculated by measuring the particle size by dispersing the powder in methanol by sonication for 5 minutes using a laser diffraction particle size distribution analyzer. In addition, let _d50 value be a particle diameter average value.

  The powder supply unit 3 includes a storage unit 32 that stores the powder P1 and a vibrator 33 that vibrates the storage unit 32 and discharges the powder P1 from the opening of the storage unit 32. A vibrator tube 331 is connected to the vibrator 33, and the vibrator tube 331 is disposed in the housing portion 32. By vibrating the vibration tube 331, the discharge of the powder P1 from the opening of the housing portion 32 is adjusted.

  The powder P <b> 1 discharged from the storage part 32 passes through the pipe L and is supplied between the outer surface of the first cylinder part 201 and the inner surface of the second cylinder part 202. A gas supply unit 7 that supplies gas for generating plasma is connected to the pipe L. The powder P <b> 1 is supplied to the pipe L, is applied to the gas flow, and falls between the outer surface of the first cylinder part 201 and the inner surface of the second cylinder part 202.

  Furthermore, the manufacturing apparatus 1A includes a halogenating unit 4 that collects the powder P1 plasma-treated in the discharge tube 2 and performs halogenation.

  The halogenating means 4 communicates with the second cylindrical portion 202 and has a powder recovery tank 41 formed in an inverted conical shape, a pipe connected to the lower end of the recovery tank 41, and an end of the pipe. The reaction container 43 connected to the part, the gas supply part 44, and the container 45 are provided.

A valve 421 is attached to the pipe 42.
The reaction vessel 43 is a vessel for halogenating the powder discharged from the discharge tube 2. The reaction vessel 43 is connected to a gas supply unit 44 for supplying a gas containing halogen atoms. In addition, a container 45 filled with soda lime is connected to the reaction container 43.

The manufacturing apparatus used in the present invention is not limited to the above-described embodiment, but includes modifications and improvements as long as the object of the present invention can be achieved.
For example, in the above-described embodiment, the powder P1 is dropped between the first electrode 231 and the second electrode 232 in a gas flow for generating plasma. You may use the gas only for conveyance for conveying.
Furthermore, in the said embodiment, although the powder supply part 3 supplied powder P1 with the vibration by the vibrator 33, the powder supply method is not restricted to this.

Further, in addition to the structure of the manufacturing apparatus of the above embodiment, as shown in FIG. 3, a vibrating portion 6 for vibrating the first cylindrical portion 201 may be attached to the first cylindrical portion 201. By vibrating the first tube portion 201, the powder P1 supplied between the first tube portion 201 and the second tube portion 202 is vibrated, and the powder P1 is moved to the first tube portion 201. And the second cylindrical portion 202 can be easily dropped in the discharge chamber 2A. In addition, the falling speed of the powder P1 can be controlled.
Furthermore, the vibration part may be attached to the second cylinder part 202, or the vibration part may be attached to both the first cylinder part 201 and the second cylinder part 202.
Moreover, in the said embodiment, although the liquid was used as a cooling medium, you may use gas.

  Next, the manufacturing method of the powder P2 by the method (1) using the manufacturing apparatus 1A as described above will be described.

  First, plasma is generated in the discharge tube 2. Specifically, a gas for generating plasma is supplied from the gas supply unit 7 between the first electrode 231 and the second electrode 232. Examples of the gas for generating plasma include rare gases such as helium gas and argon gas. A gas obtained by mixing two or more of these gases may be used as a plasma generating gas. In addition, a gas for generating plasma is also supplied from the discharge gas supply port 221.

Applied to the first electrode 231 and the second electrode 232, plasma is generated. Note that plasma is generated in a pressure state of 3 × 10 ⁴ Pa or more and 15 × 10 ⁴ Pa or less (so-called atmospheric pressure plasma).

  Next, the powder P <b> 1 is supplied from the powder supply unit 3 to the discharge tube 2. At this time, the vibration tube 331 is vibrated by the vibrator 33 in order to adjust the discharge amount of the powder P1 from the storage portion 32. The powder P1 falls on the gas flow from the gas supply unit 7 and falls into the discharge tube 2. The powder P1 is guided to the discharge chamber 2A in the discharge tube 2 by using a part of the plasma generating gas.

  Next, the powder P1 is subjected to plasma treatment in the discharge tube 2, and unbonded hands are formed on the surface of the particles constituting the powder. While the powder P1 is present in an inert gas such as argon or helium, the dangling bonds of the powder P1 remain as they are.

  Such powder P1 is recovered by the halogenating means 4. Specifically, the powder P1 reaches the reaction vessel 43 through the powder recovery tank 41 and the pipe 42. In advance, a gas containing a halogen atom is supplied from the gas supply unit 44 into the reaction vessel 43. In the reaction vessel 43, halogen atoms are bonded to the dangling bonds of the powder P1, and the powder P1 is halogenated. Thereby, it is possible to obtain a powder P2 containing resin fine particles having a halogenated surface.

  The gas containing halogen atoms in the reaction vessel 43 passes through the vessel 45 filled with soda lime and is released to the outside. At this time, halogen atoms are adsorbed and removed from soda lime.

  Furthermore, with reference to FIG. 1, the manufacturing method of the resin fine particle by which the surface described in the method (2) was processed with the reactive gas is demonstrated based on drawing.

  As in the method (1), first, plasma is generated in the discharge tube 2. Specifically, a gas for generating plasma is supplied from the gas supply unit 7 between the first electrode 231 and the second electrode 232. Examples of the gas for generating plasma include rare gases such as helium gas and argon gas. A gas obtained by mixing two or more of these gases may be used as a plasma generating gas. In addition, a mixed gas of plasma generating gas and reactive gas is supplied from the discharge gas supply port 221. Specifically, a gas for generating plasma is mixed with vaporized bromoform or bromine gas, and a gas obtained by mixing two or more of these gases may be mixed as a reactive gas.

Applied to the first electrode 231 and the second electrode 232, plasma is generated. Note that plasma is generated in a pressure state of 3 × 10 ⁴ Pa or more and 15 × 10 ⁴ Pa or less (so-called atmospheric pressure plasma).

  Next, the powder P <b> 1 is supplied from the powder supply unit 3 to the discharge tube 2. At this time, the vibration tube 331 is vibrated by the vibrator 33 in order to adjust the discharge amount of the powder P1 from the storage portion 32. The powder P1 falls on the gas flow from the gas supply unit 7 and falls into the discharge tube 2. The powder P1 is guided to the discharge chamber 2A in the discharge tube 2 by using a part of the plasma generating gas.

  Next, the powder P <b> 1 is plasma-treated in the discharge tube 2. By performing plasma treatment in a gas atmosphere in which a reactive gas is mixed, halogen and halogen-containing atomic groups can be directly bonded to the particle surface constituting the powder.

  Such powder P1 is collected in the reaction vessel 43. Specifically, the powder P1 reaches the reaction vessel 43 through the powder recovery tank 41 and the pipe 42. Thereby, it is possible to obtain a powder P2 containing resin fine particles whose surface is directly halogenated by plasma treatment.

<Process (B)>
Hereinafter, the step (B) will be described.

  The method for producing a resin powder containing coated resin fine particles in the present embodiment is such that the surface of the resin fine particles constituting the powder P2 is graft-polymerized by surface graft polymerization of a monomer having at least one carbon-carbon unsaturated bond. A coating layer made of a coalescence is formed.

  Specifically, on the surface of the resin fine particles constituting the powder P2, a carbon-carbon unsaturated bond is started from the radical polymerization initiation group (halogen atom bonded to the dangling bond of the powder P1) existing on the surface. Is produced by surface graft polymerization of a monomer having at least one.

  It is possible to control the primary structure such as control of molecular weight, molecular weight distribution, and molecular terminal of the polar polymer by surface graft polymerization of the monomer by controlled radical polymerization method on the surface of the resin fine particles constituting the powder P2. .

  In the present embodiment, the type of the controlled radical polymerization method for forming the coating layer made of the graft polymer is not particularly limited, but a more appropriate method for the type of the graft polymer and the polymerization conditions can be selected.

  In this embodiment, the atom transfer radical polymerization method is a preferred controlled radical polymerization method for introducing a graft polymer (forming a coating layer) due to the richness of selectable monomer species.

  In performing the controlled radical polymerization according to the present invention, a solvent may or may not be used. Any solvent can be used as long as it does not inhibit the polymerization reaction and does not dissolve the resin fine particles into which radical polymerization initiating groups have been introduced. For example, fragrances such as benzene, toluene and xylene can be used. Aromatic hydrocarbon solvents, aliphatic hydrocarbon solvents such as pentane, hexane, heptane, octane, nonane and decane, alicyclic hydrocarbon solvents such as cyclohexane, methylcyclohexane and decahydronaphthalene, chlorobenzene, dichlorobenzene, Chlorinated hydrocarbon solvents such as trichlorobenzene, methylene chloride, chloroform, carbon tetrachloride and tetrachloroethylene, alcohols such as methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol and tert-butanol Solvents, ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone; ester solvents such as ethyl acetate and dimethyl phthalate, ether systems such as dimethyl ether, diethyl ether, di-n-amyl ether, tetrahydrofuran and dioxyanisole A solvent etc. can be mention | raise | lifted. Water can also be used as a solvent. These solvents may be used alone or in admixture of two or more.

  The polymerization temperature can be arbitrarily set as long as the resin fine particles into which the radical polymerization initiating group is introduced do not melt or swell and the radical polymerization reaction proceeds. Although it is not uniform depending on the degree of polymerization of the desired polymer and the kind and amount of the radical polymerization initiator and solvent to be used, it is usually -50 ° C to 150 ° C, preferably 0 ° C to 80 ° C. In some cases, the polymerization reaction can be carried out under reduced pressure, normal pressure, or increased pressure. The polymerization reaction is preferably performed in an inert gas atmosphere such as nitrogen or argon after oxygen is removed to suppress side reactions.

  The resin powder of the present invention thus obtained is considered to be used for applications such as resin additives, film additives, paint additives, cosmetics, spacers for liquid crystal display elements, and resin fine particles for conductive fine particles. It is done.

EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to these Examples.
First, particles to be subjected to bromination and subsequent graft polymerization were produced as follows.

(Production of ultra-high molecular weight polyethylene (PE) fine particles (average particle size 9 μm))
(Preparation of Mg-containing support component (B1-1))
Anhydrous magnesium chloride 95.2 g (1.0 mol), decane 442 ml and 2-ethylhexyl alcohol 390.6 g (3.0 mol) were reacted at 130 ° C. for 2 hours to obtain a homogeneous solution (component (B1)). Next, 50 ml of the component (B1) (50 mmol in terms of magnesium atom), 283 ml of purified decane, and 117 ml of chlorobenzene were charged into a flask with an internal volume of 1000 ml sufficiently purged with nitrogen, and CLEAMIX CLM-0.8S manufactured by Organo Corporation. Then, 52 mmol of triethylaluminum diluted with purified decane was added dropwise over 30 minutes while maintaining the liquid temperature at 0 ° C. with stirring at 15000 rpm. Thereafter, the liquid temperature was raised to 80 ° C. over 5 hours and reacted for 1 hour. Next, while maintaining 80 ° C., 98 mmol of purified decane-diluted triethylaluminum was added dropwise over a period of 30 minutes, and then the reaction was further carried out for 1 hour. After completion of the reaction, the solid part was collected by filtration, thoroughly washed with toluene, and 100 ml of toluene was added to form a toluene slurry of the Mg-containing support component (B1-1).

(Preparation of solid catalyst component (B1-1-A2-172))
Into a flask with an internal volume of 1000 ml sufficiently purged with nitrogen, 20 mmol of Mg-containing carrier component (B1-1) in terms of magnesium atom and 600 ml of purified toluene were charged, and the following transition metal compound was maintained while stirring at room temperature. 20 ml of a toluene solution (0.0001 mmol / ml) of (A2-172) was added dropwise over 20 minutes. After stirring for 1 hour, the solid part was collected by filtration, thoroughly washed with toluene, and purified decane was added to form a 200 ml decane slurry of the solid catalyst component (B1-1-A2-172).

Preparation of ultra-high molecular weight PE fine particles (average particle size 9 μm) 500 ml of purified heptane was charged into a 1 liter SUS autoclave sufficiently purged with nitrogen, and 100 liter / hr of ethylene was allowed to flow at room temperature for 15 minutes. And the gas phase was saturated. Subsequently, after the temperature was raised to 63 ° C., 1.25 ml of a decane solution of triethylaluminum (1.0 mmol / ml in terms of Al atoms) and solid catalyst component (B1-1-A2) were allowed to flow through ethylene at 12 liter / hr. -172), 5.33 ml (0.00008 mmol in terms of Zr atom) was added, and the mixture was stirred for 3 minutes while maintaining the temperature. Immediately after adding 40 mg of Emulgen E-108 (manufactured by Kao Corp.) Started. The ethylene pressure was increased to 0.8 MPa · G over 10 minutes, and polymerization was carried out at 65 ° C. for 2 hours while supplying ethylene so as to maintain the pressure. Thereafter, the autoclave was cooled to depressurize ethylene. The obtained polymer slurry was filtered, washed with hexane, and dried under reduced pressure at 80 ° C. for 10 hours to obtain 51.9 g of polymer particles. The median diameter (d50) of the produced polymer particles was 9.4 μm, and the Cv value was 13.5%. The standard deviation, d50, was calculated by measuring the particle diameter by dispersing the powder in methanol by ultrasonic treatment for 5 minutes using a laser diffraction particle size distribution analyzer.

[Example 1]
(1) Synthesis of brominated polyethylene fine particles by plasma treatment Formation of Unbonded Hands on Fine Particle Surface by Plasma Treatment Using the manufacturing apparatus 1A shown in FIG. 1, the powder (powder P1) composed of the ultrahigh molecular weight polyethylene fine particles was treated. After 5 g of the powder P1 was stored in the storage unit 32, gas replacement was performed with helium gas, the opening of the storage unit 32 was opened, and at the same time, the vibrator 33 was operated to start supplying the powder P1.
In order to form plasma, high frequency power of 13.56 MHz is applied to form plasma. The powder P1 is plasma-treated in the discharge chamber between the first electrode 231 and the second electrode 232. The high frequency was supplied with power by dividing a power application time and a rest time into 50% and 50% by synchronizing a 10 kHz pulse. The supplied high frequency power was adjusted and supplied from 1.8 kW to 2.5 kW. The plasma irradiation time was 30 minutes for 5 g of powder P1. The supply flow rate of helium was 1 L / min from the gas supply inlet 71 and 2 L / min from the discharge gas supply port 221.
The plasma-treated powder P1 was collected in the reaction vessel 43 and subsequently subjected to bromine gas treatment.

2. Bromine gas treatment In advance, the bromine liquid was frozen with liquid nitrogen to lower the vapor pressure, and the reaction vessel 43 was evacuated with an oil rotary pump (not shown). Next, the supply valve 432 was opened, bromine gas was introduced into the reaction vessel 43, and the powder P1 and bromine were brought into contact with each other for 1 hour while maintaining the pressure at 100 Torr. The powder P2 obtained by performing the bromine gas treatment in this way was measured by X-ray photoelectron spectroscopy (XPS), and the elemental composition ratio on the surface of the fine particles constituting the powder P2 was quantified. It was confirmed that it was 0.72%. Further, when the content of bromine element in the powder P2 obtained by ion chromatography was measured, it was 0.034 wt%.

(2) Synthesis of core-shell fine particles by surface graft polymerization In a glass reaction vessel having an internal volume of 20 ml, 2.0 g of powder composed of the brominated PE fine particles obtained in (1), 8.3 ml of toluene, and methyl methacrylate (MMA) Add 3.3 ml and 1.7 ml of glycidyl methacrylate (GMA), and perform nitrogen substitution by freeze deaeration. While maintaining the gas phase portion under a nitrogen atmosphere at 25 ° C., 7.65 mg of copper (I) bromide, N, N, N ′, N ″, N ″ -pentamethyldiethylenetriamine (PMDETA) 0.5 ml of a 18.5 mg toluene solution was added, the temperature was raised to 80 ° C., and stirring was continued for 150 minutes. Thereafter, the cooled reaction liquid was filtered, and the obtained powder was made into a 25 ml acetone slurry, stirred for 30 minutes, filtered again, and then stirred as a 25 ml methanol slurry for 30 minutes for washing. After washing, the powder obtained by filtration was dried at 80 ° C. under reduced pressure for 10 hours. The graft polymer content calculated from the yield change was 2.2 wt%, and the mass of the graft polymer per unit surface was 32.4 mg / m ² .
Moreover, using the density (1.2 mg / m ³ ) of a general acrylic resin, the mass per unit surface area described above is converted to a thickness of 27.0 nm, which is an actual value measured by transmission electron microscope observation described later. The value approximated to 22 nm.

[Example 2]
Synthesis of core-shell fine particles by surface graft polymerization In a glass reaction vessel having an internal volume of 20 ml, 500 mg of powder composed of brominated PE fine particles obtained in Example 1 (1), 8.3 ml of toluene, methyl methacrylate (MMA), and 3. 3 ml and 1.7 ml of glycidyl methacrylate (GMA) are added, and nitrogen substitution is performed by freeze deaeration. While maintaining the gas phase portion under a nitrogen atmosphere at 25 ° C., 7.65 mg of copper (I) bromide, N, N, N ′, N ″, N ″ -pentamethyldiethylenetriamine (PMDETA) 0.5 ml of a 18.5 mg toluene solution was added, the temperature was raised to 80 ° C., and stirring was continued for 150 minutes. Thereafter, the cooled reaction liquid was filtered, and the resulting powder was stirred for 10 minutes in 10 ml acetone slurry, filtered again, and then stirred and washed as 10 ml methanol slurry for 30 minutes. After washing, the powder obtained by filtration was dried at 80 ° C. under reduced pressure for 10 hours. The content of the graft polymer was calculated from the change in yield and found to be 0.34 wt%, and the mass of the polar polymer per unit surface was 5.0 mg / m ² .
Moreover, using the density (1.2 mg / m ³ ) of a general acrylic resin, the mass per unit surface area described above corresponds to 4.2 nm, which corresponds to 4.2 nm. The value approximated to 3 nm.

[Example 3]
(1) Synthesis of Brominated PE Fine Particles by Plasma Treatment Using the production apparatus 1A shown in FIG. 1, the powder (powder P1) made of the ultra high molecular weight polyethylene fine particles was treated. After 5 g of powder P1 is stored in the storage section 32, gas replacement is performed with helium gas. After filling the inside of the discharge tube 2 with helium gas, tribromomethane heated to 100 ° C. is gasified by bubbling and introduced into the discharge field together with the carrier gas helium. The distribution channel is heated with a ribbon heater in order to prevent liquefaction of bromoform. Next, in order to form plasma, high frequency power of 13.56 MHz is applied to form plasma. Next, the opening of the container 32 is opened, and at the same time, the vibrator 33 is operated to start supplying the powder P1, and the powder P1 is plasma-treated in the discharge chamber between the first electrode 231 and the second electrode 232. . The high frequency was supplied with power by dividing a power application time and a rest time into 50% and 50% by synchronizing a 10 kHz pulse. The supplied high frequency power was adjusted and supplied from 1.8 kW to 2.2 kW. The plasma irradiation time was 30 minutes for 5 g of powder P1. The supply flow rate of helium was 2 L / min from the gas supply inlet 71 and 8 L / min from the discharge gas supply port 221.
The powder that passed through the plasma was collected in a reaction vessel 43 mounted below the discharge tube 2 and left for 3 hours so as not to touch the air.
The powder P2 thus obtained was analyzed by X-ray photoelectron spectroscopy (XPS), and the elemental composition ratio on the surface of the fine particles constituting the powder P2 was quantified. It was confirmed that there was. Further, when the content of bromine element in the powder P2 obtained by ion chromatography was measured, it was 0.160 wt%.

(2) Synthesis of core-shell fine particles by surface graft polymerization In a glass reaction vessel having an internal volume of 20 ml, 500 mg of powder composed of the brominated PE fine particles obtained in (1), 8.3 ml of toluene, methyl methacrylate (MMA) 3. 3 ml and 1.7 ml of glycidyl methacrylate (GMA) are added, and nitrogen substitution is performed by freeze deaeration. While maintaining the gas phase portion under a nitrogen atmosphere at 25 ° C., 7.65 mg of copper (I) bromide, N, N, N ′, N ″, N ″ -pentamethyldiethylenetriamine (PMDETA) 0.5 ml of a 18.5 mg toluene solution was added, the temperature was raised to 80 ° C., and stirring was continued for 150 minutes. Thereafter, the cooled reaction solution was filtered, and the obtained powder was washed with 10 ml of an acetone slurry for 30 min and washed with 10 ml of a methanol slurry for 30 min. After washing, the powder obtained by filtration was dried at 80 ° C. under reduced pressure for 10 hours. When the content of the graft polymer was calculated from the yield change, it was 1.8 wt%, and the mass of the graft polymer per unit surface was 26.5 mg / m ² .
Moreover, when the density per unit surface area mentioned above is converted into thickness using the density (1.2 mg / m ³ ) of a general acrylic resin, it corresponds to 22.1 nm, and is an actual measurement value observed with a transmission electron microscope described later. The value approximated to 18 nm.

[Example 4]
Using the manufacturing apparatus 1A shown in FIG. 1, the powder (powder P1) made of the ultrahigh molecular weight polyethylene fine particles was processed. After 5 g of powder P1 is stored in the storage section 32, gas replacement is performed with helium gas. After filling the inside of the discharge tube 2 with helium gas, tribromomethane heated to 100 ° C. is gasified by bubbling and introduced into the discharge field together with helium at a flow rate of 3.0 mL / min. The distribution channel is heated with a ribbon heater in order to prevent liquefaction of bromoform. Next, in order to form plasma, high frequency power of 13.56 MHz is applied to form plasma. Next, the opening of the container 32 is opened, and at the same time, the vibrator 33 is operated to start supplying the powder P1, and the powder P1 is plasma-treated in the discharge chamber between the first electrode 231 and the second electrode 232. . The high frequency was supplied with power by dividing a power application time and a rest time into 50% and 50% by synchronizing a 10 kHz pulse. The supplied high frequency power was adjusted and supplied from 1.8 kW to 2.2 kW. The plasma irradiation time was 30 minutes for 5 g of powder P1. The supply flow rate of helium was 2 L / min from the gas supply inlet 71 and 8 L / min from the discharge gas supply port 221.
The powder that passed through the plasma was collected in a reaction vessel 43 mounted below the discharge tube 2 and left for 3 hours so as not to touch the air.
The powder P2 thus obtained was analyzed by X-ray photoelectron spectroscopy (XPS), and the elemental composition ratio on the surface of the fine particles constituting the powder P2 was quantified. It was confirmed that there was.

(2) Synthesis of core-shell fine particles by surface graft polymerization In advance, methyl methacrylate (MMA) and glycidyl methacrylate (GMA) to be used are treated by a solid-phase extraction method using alumina as an adsorbent to remove the polymerization inhibitor. In a glass reaction container having an internal volume of 20 ml, 500 mg of the powder composed of the brominated PE fine particles obtained in (1), 8.3 ml of toluene, 3.3 ml of methyl methacrylate (MMA), and 1.7 ml of glycidyl methacrylate (GMA) are placed. And nitrogen substitution by freeze degassing. While maintaining the gas phase portion under a nitrogen atmosphere at 25 ° C., 7.65 mg of copper (I) bromide, N, N, N ′, N ″, N ″ -pentamethyldiethylenetriamine (PMDETA) 0.5 ml of a 18.5 mg toluene solution was added, the temperature was raised to 80 ° C., and stirring was continued for 150 minutes. Thereafter, the cooled reaction solution was filtered, and the obtained powder was washed with 10 ml of an acetone slurry for 30 min and washed with 10 ml of a methanol slurry for 30 min. After washing, the powder obtained by filtration was dried at 80 ° C. under reduced pressure for 10 hours. The content of the graft polymer calculated from the yield change was 4.2 wt%, and the mass of the graft polymer per unit surface was 59.2 mg / m ² . According to observation with a transmission electron microscope, the film thickness was 26 nm.

[Example 5]
Using the manufacturing apparatus 1A shown in FIG. 1, the powder (powder P1) made of the ultrahigh molecular weight polyethylene fine particles was processed. After 5 g of powder P1 is stored in the storage section 32, gas replacement is performed with helium gas. After filling the inside of the discharge tube 2 with helium gas, tribromomethane heated to 100 ° C. is gasified by bubbling and introduced into the discharge field together with helium at a flow rate of 3.5 mL / min. The distribution channel is heated with a ribbon heater in order to prevent liquefaction of bromoform. Next, in order to form plasma, high frequency power of 13.56 MHz is applied to form plasma. Next, the opening of the container 32 is opened, and at the same time, the vibrator 33 is operated to start supplying the powder P1, and the powder P1 is plasma-treated in the discharge chamber between the first electrode 231 and the second electrode 232. . The high frequency was supplied with power by dividing a power application time and a rest time into 50% and 50% by synchronizing a 10 kHz pulse. The supplied high frequency power was adjusted and supplied from 1.8 kW to 2.2 kW. The plasma irradiation time was 30 minutes for 5 g of powder P1. The supply flow rate of helium was 2 L / min from the gas supply inlet 71 and 8 L / min from the discharge gas supply port 221.
The powder that passed through the plasma was collected in a reaction vessel 43 mounted below the discharge tube 2 and left for 3 hours so as not to touch the air.
The powder P2 thus obtained was analyzed by X-ray photoelectron spectroscopy (XPS), and the elemental composition ratio on the surface of the fine particles constituting the powder P2 was quantified. It was confirmed that there was.

(2) Synthesis of core-shell fine particles by surface graft polymerization In advance, methyl methacrylate (MMA) and glycidyl methacrylate (GMA) to be used are treated by a solid-phase extraction method using alumina as an adsorbent to remove the polymerization inhibitor. In a glass reaction container having an internal volume of 20 ml, 500 mg of the powder composed of the brominated PE fine particles obtained in (1), 8.3 ml of toluene, 3.3 ml of methyl methacrylate (MMA), and 1.7 ml of glycidyl methacrylate (GMA) are placed. And nitrogen substitution by freeze degassing. While maintaining the gas phase portion under a nitrogen atmosphere at 25 ° C., 7.65 mg of copper (I) bromide, N, N, N ′, N ″, N ″ -pentamethyldiethylenetriamine (PMDETA) 0.5 ml of a 18.5 mg toluene solution was added, the temperature was raised to 80 ° C., and stirring was continued for 150 minutes. Thereafter, the cooled reaction solution was filtered, and the obtained powder was washed with 10 ml of an acetone slurry for 30 min and washed with 10 ml of a methanol slurry for 30 min. After washing, the powder obtained by filtration was dried at 80 ° C. under reduced pressure for 10 hours. The graft polymer content calculated from the yield change was 7.4 wt%, and the mass of the graft polymer per unit surface was 109.0 mg / m ² . According to observation with a transmission electron microscope, the film thickness was 34 nm.

[Example 6]
Using the manufacturing apparatus 1A shown in FIG. 1, the powder (powder P1) made of the ultrahigh molecular weight polyethylene fine particles was processed. After 5 g of powder P1 is stored in the storage section 32, gas replacement is performed with helium gas. After filling the inside of the discharge tube 2 with helium gas, tribromomethane heated to 100 ° C. is gasified by bubbling and introduced into the discharge field together with helium at a flow rate of 4.0 mL / min. The distribution channel is heated with a ribbon heater in order to prevent liquefaction of bromoform. Next, in order to form plasma, high frequency power of 13.56 MHz is applied to form plasma. Next, the opening of the container 32 is opened, and at the same time, the vibrator 33 is operated to start supplying the powder P1, and the powder P1 is plasma-treated in the discharge chamber between the first electrode 231 and the second electrode 232. . The high frequency was supplied with power by dividing a power application time and a rest time into 50% and 50% by synchronizing a 10 kHz pulse. The supplied high frequency power was adjusted and supplied from 1.8 kW to 2.2 kW. The plasma irradiation time was 30 minutes for 5 g of powder P1. The supply flow rate of helium was 2 L / min from the gas supply inlet 71 and 8 L / min from the discharge gas supply port 221.
The powder that passed through the plasma was collected in a reaction vessel 43 mounted below the discharge tube 2 and left for 3 hours so as not to touch the air.
The powder P2 thus obtained was analyzed by X-ray photoelectron spectroscopy (XPS), and the elemental composition ratio on the surface of the fine particles constituting the powder P2 was quantified. It was confirmed that there was.

(2) Synthesis of core-shell fine particles by surface graft polymerization In advance, methyl methacrylate (MMA) and glycidyl methacrylate (GMA) to be used are treated by a solid-phase extraction method using alumina as an adsorbent to remove the polymerization inhibitor. In a glass reaction container having an internal volume of 20 ml, 500 mg of the powder composed of the brominated PE fine particles obtained in (1), 8.3 ml of toluene, 3.3 ml of methyl methacrylate (MMA), and 1.7 ml of glycidyl methacrylate (GMA) are placed. And nitrogen substitution by freeze degassing. While maintaining the gas phase portion under a nitrogen atmosphere at 25 ° C., 7.65 mg of copper (I) bromide, N, N, N ′, N ″, N ″ -pentamethyldiethylenetriamine (PMDETA) 0.5 ml of a 18.5 mg toluene solution was added, the temperature was raised to 80 ° C., and stirring was continued for 150 minutes. Thereafter, the cooled reaction solution was filtered, and the obtained powder was washed with 10 ml of an acetone slurry for 30 min and washed with 10 ml of a methanol slurry for 30 min. After washing, the powder obtained by filtration was dried at 80 ° C. under reduced pressure for 10 hours. When the content of the graft polymer was calculated from the change in yield, it was 8.6 wt%, and the mass of the graft polymer per unit surface was 126.7 mg / m ² . According to observation with a transmission electron microscope, the film thickness was 36 nm.

[Comparative Example 1]
(1) Synthesis of Brominated Polyethylene Fine Particles by Chemical Method Into a 2 L glass reactor sufficiently purged with nitrogen, 300 g of the powder composed of the ultra high molecular weight PE fine particles and 1.2 L of chlorobenzene were placed, and nitrogen was added at room temperature. After carrying out bubbling (10 L / H), the temperature was raised to 80 ° C. while keeping the gas phase part in a nitrogen atmosphere, 3.0 ml of bromine was added, and the mixture was heated and stirred for 6 hours. The powder obtained by filtering the reaction solution was added to 2 L of acetone, stirred at room temperature, filtered, and the polymer was dried under reduced pressure at 80 ° C. to obtain 298 g of white PE powder. The content of bromine atoms contained in the obtained polymer was 0.040 wt% from ion chromatography analysis.

(2) Synthesis of core-shell fine particles by surface graft polymerization In a glass reaction vessel with an internal volume of 20 ml, 2.00 g of powder composed of brominated PE fine particles obtained in (1), 8.3 ml of toluene, methyl methacrylate (MMA) Add 3.3 ml and 1.7 ml of glycidyl methacrylate (GMA), and perform nitrogen substitution by freeze deaeration. While maintaining the reaction vessel under a nitrogen atmosphere as it is, stirring at 25 ° C., 7.65 mg of copper (I) bromide, N, N, N ′, N ″, N ″ -pentamethyldiethylenetriamine (PMDETA) 18.5 mg 0.5 ml of toluene solution was added, the temperature was raised to 80 ° C., and stirring was continued for 150 minutes. Thereafter, the cooled reaction liquid was filtered, and the resulting powder was stirred for 10 minutes in 10 ml acetone slurry, filtered again, and then stirred and washed as 10 ml methanol slurry for 30 minutes. After washing, the powder obtained by filtration was dried at 80 ° C. under reduced pressure for 10 hours. The obtained powder was dried at 60 ° C. under reduced pressure for 10 hours. The content of the graft polymer was calculated from the yield change and found to be 1.9 wt%. In addition, as shown in the observation result by the transmission electron microscope shown in FIG. 10, the coating layer was not observed even though the content of the graft polymer was the same as that of [Example 1] and [Example 3]. It was.

[Comparative Example 2]
Synthesis of Core Shell Fine Particles by Surface Graft Polymerization Into a glass reactor having an internal volume of 2 L sufficiently purged with nitrogen, 200 g of brominated PE powder obtained in Comparative Example 1 (1), 333 ml of methyl methacrylate (MMA), 167 ml of glycidyl methacrylate, 833 ml of toluene was added and stirred at 25 ° C. To this slurry were added copper (I) bromide (765 mg, 5.33 mmol) and PMDETA ml (10.67 mmol), and the mixture was heated to 80 ° C. and stirred for 150 minutes. Thereafter, the reaction solution slurry was filtered, and the polymer on the filter paper was added to 2.5 L of acetone and stirred for 30 minutes, followed by filtration and washing with methanol. The obtained polymer was dried at 80 ° C. under reduced pressure, washed and then dried under reduced pressure to obtain 224.86 g of a solid polymer. The content of the graft polymer calculated from the increase in yield was 11 wt%. Further, as observed with a transmission electron microscope, which will be described later, the coating layer was not observed even though the content of the graft polymer was 5 times higher than that of the Examples.

<Surface morphology observation>
The core-shell fine particles obtained in Examples 1 to 3 and the fine particles obtained in Comparative Examples 1 and 2 were subjected to cross-sectional observation with a transmission electron microscope. The fine particles were embedded in an epoxy resin, faced with a microtome, stained with ruthenium oxide, and observed with a transmission electron microscope. FIGS. 4 to 9 sequentially show the observation results of the core-shell fine particles obtained in Examples 1 to 6 using a transmission electron microscope, and FIGS. 10 and 11 show the transmission electron microscopes of the fine particles obtained in Comparative Examples 1 and 2, respectively. The observation results are shown in order.

  In Examples 1 to 6, a uniform and clear coating layer having a thickness of 5 to 40 nm made of a copolymer of MMA and GMA was observed. In Comparative Examples 1 and 2, a clear coating layer was observed. I couldn't.

<Dispersibility evaluation>
The powder obtained in Example 1 and Comparative Examples 1 and 2 and the powder composed of unmodified PE fine particles were evaluated for dispersibility by the following method. Under a condition of 25 ° C., 5 mg of a dried resin powder and 0.5 ml of a mixed dispersion medium of dimethylformamide (DMF) and water prepared at a predetermined volume ratio were placed in a 1-ml sample bottle and shaken. Thereafter, ultrasonic irradiation was carried out for 3 minutes. After leaving still for 30 minutes, 10 μl of the obtained dispersion was taken out with a micro syringe (manufactured by HAMILTON (80630)), dropped on a slide glass, covered with a cover glass, and an optical microscope (manufactured by KEYENCE, “VH-Z450”). ) And observed at a magnification of 450 times. Using the software “macview”, the number of particles observed at a field size of 1013 μm × 1345 μm was counted from the obtained microscopic images. For aggregated particles, one aggregate is counted as one.

  According to the above method, when the dispersibility is excellent, a large number of particles are counted because non-aggregated fine particles are observed at a high density in a fixed field of view in a microscopic observation. When the particles are settled and floating without being dispersed, or the fine particles are aggregated, the number counted is reduced. The count results are shown in Table 1, and in FIG. 12, the results of Table 1 are plotted against the dielectric constant. The dielectric constant was estimated on the assumption that volume additivity was established in the mixed dispersion medium.

According to the above results, it was found that Example 1 showed a higher dispersibility even in a dispersion medium having a high water content, while having a polar polymer content almost equivalent to that of Comparative Example 1. Furthermore, although Comparative Example 2 contained about five times as much polar polymer as Example 1, Example 1 showed higher dispersibility.
In general, when the number of counts is 500 or more, sedimentation and suspended solids cannot be confirmed by visual observation, and are uniformly dispersed.

Since the coated resin fine particles obtained in Examples 2 to 6 have a uniform and clear coating layer on the entire particle surface, it is estimated that the coated resin fine particles exhibit high dispersibility like the coated resin fine particles of Example 1. It was done. Furthermore, from the results of Examples 1 to 6, the entire surface of the resin fine particles is provided with a uniform and clear coating layer, the film thickness is greater than 0 and 60 nm or less, and the mass of the polymer per unit surface area of the resin fine particles is When it is ² to 150 mg / m ² , various properties can be imparted to the coating layer, and workability, chemical resistance, electrical properties, mechanical properties, slidability, wear resistance, impact resistance It was inferred to be excellent in properties.

  Furthermore, in order to compare the dispersibility of the powders obtained in Examples 2 to 6 with the powders obtained in Example 1 and Comparative Examples 1 and 2, dispersibility in DMF / water = 2/8. Was evaluated in the same manner as described above. Table 2 shows the counts of the powders obtained in Examples 2 to 6 and Comparative Examples 1 and 2. Furthermore, the result of having plotted the content of the graft polymer on the horizontal axis is shown in FIG.

As shown in Table 2 and FIG. 13, the coated resin fine particles obtained in this example have a remarkable improvement in dispersibility even when the content of the graft polymer is small. It was confirmed that the effect was maximized at a weight percent or more. That is, in the coating layer formed according to the present invention, the mass of the polymer per unit surface area is 0.1% by weight or more, preferably 2% by weight or more. It was inferred. On the other hand, in the comparative example, it was confirmed that the dispersibility was improved by introducing the graft polymer, but the effect was confirmed to be lower than that obtained in the examples.
Hereinafter, examples of the reference form will be added.
[1]
In the coated resin fine particles provided with a coating layer made of a polymer obtained by polymerizing monomers on the surface of the resin fine particles,
The surface of the resin fine particles and the polymer are chemically bonded by a carbon-carbon bond, and the thickness of the coating layer is greater than 0 and 60 nm or less, and the mass of the polymer per unit surface area of the resin fine particles Is a resin powder composed of coated resin fine particles, characterized in that is ² to 150 mg / m ² .
[2]
The resin powder according to [1], wherein the mass of the polymer per unit surface area of the resin fine particles is ² to 100 mg / m ² .
[3]
The resin powder according to [1] or [2], wherein the coating resin fine particles contain 0.1% by weight or more of the polymer.
[4]
The resin powder according to any one of [1] to [3], wherein the coated resin fine particles have an average particle diameter of 1 to 100 μm.
[5]
The resin powder according to any one of [1] to [4], wherein the resin fine particles are made of polyolefin.
[6]
After the surface of the resin fine particles is plasma-treated to form dangling bonds, a polymerization initiating group is bonded to the dangling bonds by contacting a reactive gas, and a monomer is surface-grafted from the polymerization initiating group. The resin powder according to any one of [1] to [5], comprising coated resin fine particles provided with a coating layer made of a polymer.
[7]
A coating layer comprising a polymer obtained by bonding the polymerization initiating group by subjecting the surface of the resin fine particles to plasma treatment in a gas atmosphere containing a reactive gas, and then subjecting the monomer to surface graft polymerization from the polymerization initiating group. The resin powder according to any one of [1] to [5], comprising coated resin fine particles.
[8]
The resin powder according to [6] or [7], wherein the plasma treatment is performed under a pressure of 3 × 10 ⁴ Pa or more and 15 × 10 ⁴ Pa or less.
[9]
The reactive gas is a gas containing a halogen atom, and the polymerization initiating group is a halogen atom or an atomic group containing a halogen atom, according to any one of [6] to [8], Resin powder.
[10]
The resin powder according to any one of [6] to [9], wherein the surface graft polymerization is atom transfer radical polymerization.
[11]
One or more types of the said monomer are selected from the organic compound which has a carbon-carbon unsaturated bond, The resin powder as described in any one of [1]-[10] characterized by the above-mentioned.
[12]
Plasma treating the resin powder to form unbonded hands on the surface of the resin fine particles constituting the resin powder;
A step of bringing a reactive gas into contact with the resin fine particles in which the dangling bonds are formed and bonding atoms or atomic groups composed of the reactive gas to the dangling bonds;
Forming a coating layer made of a polymer on the surface of the resin fine particles by surface-grafting a monomer using the atom or atomic group as a polymerization initiating group, and obtaining coated resin fine particles;
A method for producing a resin powder comprising coated resin fine particles.
[13]
A step of bonding an atom or an atomic group composed of the reactive gas to the surface of the resin fine particles by subjecting the resin powder comprising the resin fine particles to plasma treatment in a gas atmosphere containing a reactive gas;
Forming a coating layer made of a polymer on the surface of the resin fine particles by surface-grafting a monomer using the atom or atomic group as a polymerization initiating group, and obtaining coated resin fine particles;
A method for producing a resin powder comprising coated resin fine particles.
[14]
The method for producing a resin powder according to [12] or [13], wherein the plasma treatment is performed at 3 × 10 ⁴ Pa or more and 15 × 10 ⁴ Pa or less.
[15]
The method for producing a resin powder according to any one of [12] to [14], wherein the surface graft polymerization is atom transfer radical polymerization.
[16]
One or more types of the said monomer are selected from the organic compound which has a carbon-carbon unsaturated bond, The manufacturing method of the resin powder as described in any one of [12]-[15] characterized by the above-mentioned.
[17]
The method for producing a resin powder according to any one of [12] to [16], wherein the reactive gas is a gas containing a halogen atom.
[18]
The method for producing a resin powder according to any one of [12] to [17], wherein the resin fine particles are made of polyolefin.
[19]
Any one of [12] to [18], wherein the resin powder made of the resin fine particles is dropped in a discharge chamber that generates plasma, and plasma treatment is performed during the dropping of the resin powder. The manufacturing method of the resin powder as described in one.

DESCRIPTION OF SYMBOLS 1A Manufacturing apparatus 2 Discharge tube 2A Discharge chamber 3 Powder supply part 4 Halogenation means 6 Vibrating part 7 Gas supply part 25 High frequency power supply 32 Storage part 33 Vibrator 41 Recovery tank 42 Pipe 43 Reaction vessel 44 Gas supply part 45 Container 71 Gas supply Inlet 201 First tube portion 202 Second tube portions 202A and 202B Flange portion 203 Third tube portion 204 Supply pipe 205 Discharge pipe 206 Supply pipe 207 Discharge pipe 221 Discharge gas supply port 231 First electrode 232 Second Electrode 331 Vibrating tube 421 Valve 432 Supply valve L Piping P1 Powder P2 Powder

Claims (18)

In the coated resin fine particles provided with a coating layer made of a polymer obtained by polymerizing monomers on the surface of the resin fine particles,
The surface of the resin fine particles and the polymer are chemically bonded by a carbon-carbon bond, and the thickness of the coating layer is greater than 0 and 60 nm or less, and the mass of the polymer per unit surface area of the resin fine particles Is a resin powder composed of coated resin fine particles, characterized in that is ² to 150 mg / m ² ,
After the surface of the resin fine particles is plasma-treated to form dangling bonds, a polymerization initiating group is bonded to the dangling bonds by contacting a reactive gas, and a monomer is surface-grafted from the polymerization initiating group. A resin powder comprising coated resin fine particles provided with a coating layer comprising a polymer obtained in this manner . In the coated resin fine particles provided with a coating layer made of a polymer obtained by polymerizing monomers on the surface of the resin fine particles,
The surface of the resin fine particles and the polymer are chemically bonded by a carbon-carbon bond, and the thickness of the coating layer is greater than 0 and 60 nm or less, and the mass of the polymer per unit surface area of the resin fine particles Is a resin powder composed of coated resin fine particles, characterized in that is ² to 150 mg / m ² ,
A coating layer comprising a polymer obtained by bonding the polymerization initiating group by subjecting the surface of the resin fine particles to plasma treatment in a gas atmosphere containing a reactive gas, and then subjecting the monomer to surface graft polymerization from the polymerization initiating group. A resin powder comprising coated resin fine particles . The plasma treatment, 3 × ¹⁰ 4 Pa or more, 15 × ¹⁰ 4 resin powder according to claim 1 or 2, characterized in that Pa is carried out under a pressure of less than. The resin powder according to any one of claims 1 to 3 , wherein the reactive gas is a gas containing a halogen atom, and the polymerization initiating group is a halogen atom or an atomic group containing a halogen atom. body. The resin powder according to any one of claims 1 to 4 , wherein the surface graft polymerization is atom transfer radical polymerization. The mass of the polymer per unit surface area of the resin fine particles is 2 to 100 mg / m. ² The resin powder according to claim 1, wherein the resin powder is a resin powder. The resin powder according to claim 1, wherein the coating resin fine particles contain 0.1% by weight or more of the polymer. The resin powder according to any one of claims 1 to 7, wherein an average particle diameter of the coated resin fine particles is 1 to 100 µm. The resin powder according to claim 1, wherein the resin fine particles are made of polyolefin. The resin powder according to any one of claims 1 to 9 , wherein the monomer is selected from one or more organic compounds having a carbon-carbon unsaturated bond. Plasma treating the resin powder to form unbonded hands on the surface of the resin fine particles constituting the resin powder;
A step of bringing a reactive gas into contact with the resin fine particles in which the dangling bonds are formed and bonding atoms or atomic groups composed of the reactive gas to the dangling bonds;
Forming a coating layer made of a polymer on the surface of the resin fine particles by surface-grafting a monomer using the atom or atomic group as a polymerization initiating group, and obtaining coated resin fine particles;
A method for producing a resin powder comprising coated resin fine particles. A step of bonding an atom or an atomic group composed of the reactive gas to the surface of the resin fine particles by subjecting the resin powder comprising the resin fine particles to plasma treatment in a gas atmosphere containing a reactive gas;
Forming a coating layer made of a polymer on the surface of the resin fine particles by surface-grafting a monomer using the atom or atomic group as a polymerization initiating group, and obtaining coated resin fine particles;
A method for producing a resin powder comprising coated resin fine particles. The plasma treatment, 3 × ¹⁰ 4 Pa or more, the production method of the resin powder according to claim 1 1 or 1 2, characterized in that performed in 15 × ¹⁰ 4 Pa or less. Method for producing a resin powder according to any one of claims 1 1 to 1 3, wherein the surface graft polymerization is atom transfer radical polymerization. The monomer, carbon - method for producing a resin powder according to any one of claims 1 1 to 1 4, characterized in that it is one or more selected from organic compounds having a carbon-carbon unsaturated bond. The method for producing a resin powder according to any one of claims 1 to 15, wherein the reactive gas is a gas containing a halogen atom. The method for producing a resin powder according to any one of claims 1 to 16 , wherein the resin fine particles are made of polyolefin. During the discharge chamber for generating a plasma, the made of resin particles wherein the resin powder is falling, claim 1 1 to 1 7, characterized in that a plasma treatment during dropping of the resin powder 1 The manufacturing method of the resin powder as described in a term.