JP5377374B2 - Spherical urethane resin particles and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spherical urethane-based resin particle not using a non-reactive organic solvent in its manufacturing step, and a manufacturing method therefor. <P>SOLUTION: The spherical urethane-based resin particle includes a polymer component originated in a mixture containing &ge;0.05 pts.wt. and &lt;2.0 pts.wt. of a polyfunctional radical polymerizable monomer, 10-400 pts.wt. of a polyfunctional isocyanate, and 100 pts.wt. of a vinyl monomer containing an active hydrogen (meth)acrylate monomer, and does not substantially contain a non-reactive organic solvent. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to spherical urethane resin particles and a method for producing the same. More specifically, the present invention relates to spherical urethane resin particles that do not use a non-reactive organic solvent in the production process and a production method thereof.

Urethane resin particles such as (meth) acryl urethane resin particles can be used as fillers for plastics, paints, adhesives, cosmetics, optical films, and the like. For example, when used as a filler for paints, the urethane-based resin particles function as a tactile sensation improver, a matting agent, a design-imparting colorant, and the like, and can give softness and soft feeling to the coating film.

  As a method for producing urethane resin particles, a polyisocyanate prepolymer dissolved and diluted in a non-reactive organic solvent not reactive with vinyl groups and isocyanate groups such as toluene in water containing a suspension stabilizer (meta ) A method is known in which particles are obtained by mixing acrylate monomers, dispersing them in the form of particles and reacting them (see Patent Document 1).

  In the method according to Patent Document 1, the particle diameter can be adjusted by adjusting the type and amount of the suspension stabilizer. Therefore, according to this method, (meth) acryl urethane resin particles having an appropriate particle diameter can be produced according to the application.

Japanese Patent Laid-Open No. 4-185645

  However, in Patent Document 1, since the viscosity of a polyisocyanate prepolymer that is a reaction product of a diisocyanate having an isocyanate group at a terminal and a polyol is high, the viscosity is obtained by dissolving and diluting in advance in a non-reactive organic diluent solvent such as toluene. A separate adjustment step is required to reduce the. In addition, a process for recovering the solvent is also required. For this reason, an extra process such as an adjustment process and a solvent recovery process is added to the manufacturing process, resulting in problems of a decrease in productivity and an increase in production cost. Moreover, in the obtained (meth) acrylic urethane resin particles, there has been a problem that quality deterioration such as discoloration and odor occurs due to the influence of the residual solvent.

  The inventors of the present invention provide a vinyl monomer containing an active hydrogen (meth) acrylate monomer, a polyfunctional radical polymerizable monomer, and a polymerizable composition containing a polyfunctional isocyanate in a predetermined ratio in an aqueous medium. The present invention was accomplished by finding that spherical urethane-based resin particles substantially free of non-reactive organic solvent can be obtained by reacting with.

  Thus, according to the present invention, with respect to 100 parts by weight of the vinyl monomer containing the active hydrogen (meth) acrylate monomer, 0.05 part by weight or more and less than 2.0 parts by weight of the polyfunctional radical polymerizable monomer and Spherical urethane-based resin particles characterized by containing a polymer component derived from a mixture containing 10 to 400 parts by weight of a polyfunctional isocyanate and substantially free of a non-reactive organic solvent are provided.

  According to the present invention, the polyfunctional radical polymerizable monomer is 0.05 part by weight or more and less than 2.0 parts by weight with respect to 100 parts by weight of the vinyl monomer containing the active hydrogen (meth) acrylate monomer. A polymerizable composition comprising a mixture containing 10 to 400 parts by weight of a polyfunctional isocyanate, a radical polymerization initiator and a urethane curing catalyst in the presence of a suspension stabilizer and in the absence of a non-reactive organic solvent, There is provided a method for producing spherical urethane resin particles, characterized in that spherical urethane resin particles are obtained by polymerization in an aqueous medium.

  The spherical urethane-based resin particles according to the present invention have appropriate hardness, elasticity and soft feel, and since there is no deterioration in quality due to residual solvents, light diffusion films, cosmetic-related additives, paints, It can be suitably used for applications such as plastics and adhesives. Further, the thermoplastic type urethane resin particles can be suitably used as a hot melt adhesive.

  Further, when the spherical urethane-based resin particles have a phase separation structure composed of a matrix phase and a dispersed phase present in the matrix phase, the spherical urethane-based is further excellent in hardness, elasticity and soft feel. Resin particles are obtained.

  Further, when the active hydrogen (meth) acrylate monomer has one or more hydroxyl groups in the molecule, spherical urethane resin particles that are further excellent in hardness, elasticity, and soft feel can be obtained.

  Further, when the polyfunctional radical polymerizable monomer is composed of a (meth) acrylic acid ester monomer and / or an aromatic monomer, the hardness, elasticity, soft feel and light diffusibility are further increased. Excellent spherical urethane resin particles are obtained.

  In addition, when the polyfunctional isocyanate is a burette type, isocyanurate type or adduct type isocyanate having three or more isocyanate groups in the molecule, a spherical urethane system which is further excellent in hardness, weather resistance and soft feel properties Resin particles are obtained.

  Further, according to the method for producing spherical urethane resin particles according to the present invention, there is no need to separately adjust the polyisocyanate prepolymer, and the non-reactive organic solvent used for adjusting the viscosity of the viscous polyisocyanate prepolymer. Spherical urethane-based resin particles can be produced at low cost and high productivity without going through an extra step called a recovery step.

  Further, when the suspension stabilizer is a poorly water-soluble inorganic salt, spherical urethane resin particles can be produced with low cost and high productivity.

It is a SEM image of the spherical urethane type resin particle by Example 1 of this invention. It is a TEM image of the cross section of the spherical urethane type resin particle by Example 1 of this invention. It is a SEM image of the cross section of the irregular-shaped urethane type resin particle by the comparative example 1 of this invention.

  The spherical urethane-based resin particles according to the present invention (hereinafter also simply referred to as spherical particles) are polyfunctional radical polymerizable monomers 0 with respect to 100 parts by weight of a vinyl monomer containing an active hydrogen (meth) acrylate monomer. It contains a polymer component derived from a mixture containing 0.05 parts by weight or more and less than 2.0 parts by weight and 10 to 400 parts by weight of polyfunctional isocyanate. The spherical particles are substantially free of non-reactive organic solvent. (Meth) acryl refers to acryl or methacryl.

  In the present invention, the spherical shape means that the particles are substantially spherical when the particles are observed with a scanning electron microscope, and the major axis of the particle diameter is 1.2 times or less, preferably 1.1 times or less of the minor axis. In this case, no conspicuous irregularities are observed on the surface of the particles.

The active hydrogen (meth) acrylate monomer means a (meth) acrylate monomer having one or more active hydrogens in the molecule. The particles are usually obtained by suspension polymerization. In the present invention, the active hydrogen (meth) acrylate monomer also serves as a dilution solvent in the polymerization system. Therefore, the viscosity of the monomer mixture can be adjusted by mixing with a relatively viscous polyfunctional isocyanate. As a result, it is possible to eliminate difficulty in handling due to an increase in the viscosity of the suspension of the monomer mixture during polymerization. Therefore, non-reactive organic solvents such as toluene are not used in the present invention.
In addition, the non-reaction of a non-reactive organic solvent means that it has no polymerizability with a vinyl group or an isocyanate group contained in a vinyl monomer or polyfunctional isocyanate. Specific examples of non-reactive organic solvents include aliphatic hydrocarbons such as butane, hexane, cyclohexane, acetone, chloroform, dichloromethane, isooctane, octane, and nonane, aromatic hydrocarbons such as toluene and xylene, and ethyl acetate. Is mentioned.

The active hydrogen (meth) acrylate monomer is not particularly limited as long as it has one or more active hydrogens in the molecule. Here, active hydrogen means a hydrogen atom that can react with an isocyanate group such as a hydroxyl group, an amino group (primary or secondary), or a carboxyl group. For example, (meth) acrylic acid hydroxyesters such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, glycerin di (meth) acrylate, or 2-aminoethyl Examples include (meth) acrylic acid amino esters containing —NH ₂ or —NH groups such as (meth) acrylate, and (meth) acrylic acids containing carboxyl groups such as methacrylic acid and acrylic acid.

  In addition to the active hydrogen (meth) acrylate monomer, an active hydrogen-free (meth) acrylate monomer may be used as the vinyl monomer. The active hydrogen-free (meth) acrylate monomer refers to a (meth) acrylate monomer that does not contain a group that gives a hydrogen atom (active hydrogen) that can react with an isocyanate group in the molecule.

Active hydrogen-free (meth) acrylate monomers include vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate , N-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, 2-chloroethyl acrylate, phenyl acrylate, methyl α-chloroacrylate, methyl methacrylate, ethyl methacrylate, Propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, phenyl methacrylate, a Acrylic acid dimethylaminoethyl, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, and (meth) acrylic acid esters such as diethylaminoethyl methacrylate.
The proportion of the active hydrogen (meth) acrylate monomer in the vinyl monomer is preferably 5 to 95 parts by weight in 100 parts by weight of the vinyl monomer. More preferably, it is 10 to 90 parts by weight.

Examples of vinyl monomers other than (meth) acrylate monomers include acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, acrylamide, and methacrylamide, vinyl methyl ether, vinyl ethyl ether, and vinyl isobutyl ether. Vinyl ethers such as vinyl methyl ketone, vinyl hexyl ketone, vinyl ketones such as methyl isopropenyl ketone, N-vinyl compounds such as N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole and N-vinyl pyrrolidone, vinyl naphthalene Salt, styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, p-ethyl styrene, 2,4-dimethyl styrene, pn-butyl styrene, p-tert-butyl styrene, pn-hex Styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, p-methoxy styrene, p-phenyl styrene, p-chloro styrene, 3,4-di Examples thereof include styrene such as chlorostyrene and derivatives thereof.
An active hydrogen-free (meth) acrylate monomer is preferred because of excellent weather resistance.

  A polyfunctional radically polymerizable monomer refers to a monomer having two or more radically polymerizable double bonds. Examples of the polyfunctional radical polymerizable monomer include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetradecaethylene glycol di (meth) acrylate, and nonaethylene glycol. Di (meth) acrylate, tetradecaethylene glycol di (meth) acrylate, decaethylene glycol di (meth) acrylate, pentadecaethylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1,4 -Butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, glycerin di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythru Tetra (meth) acrylate, diethylene glycol di (meth) acrylate phthalate, caprolactone-modified dipentaerythritol hexa (meth) acrylate, caprolactone-modified hydroxybivalic acid ester neopentyl glycol diacrylate, polyester acrylate, urethane acrylate, etc. ) Acrylic ester polyfunctional monomers, divinylbenzene, divinylnaphthalene and aromatic polyfunctional vinyl monomers which are derivatives thereof. Among these, (meth) acrylic acid ester polyfunctional monomers are preferable. These monomers may be used alone or in combination of two or more.

  The spherical particles include 100 parts by weight of a vinyl monomer containing an active hydrogen (meth) acrylate monomer, 0.05 part by weight or more and less than 2.0 parts by weight of a polyfunctional radical polymerizable monomer and 10 to 10 parts of a polyfunctional isocyanate. A polymer component derived from a mixture containing 400 parts by weight is included. The amount of the polyfunctional radically polymerizable monomer contained in the monomer mixture is more preferably 0.2 to 1.5 parts by weight. If it is less than 0.05 parts by weight, the solvent resistance may decrease. On the other hand, when the amount exceeds 2.0 parts by weight, the particle shape may be deformed.

  The polyfunctional isocyanate is not particularly limited, and examples thereof include aromatic, chain aliphatic or alicyclic difunctional isocyanate, trifunctional or higher isocyanate.

  Examples of the bifunctional isocyanate include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4′-diphenylmethane diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, Xylylene diisocyanate, isophorone diisocyanate, trimethylhexamethylene diisocyanate, 1,4-cyclohexylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, 3,3'-dimethoxy- 4,4′-biphenylene diisocyanate, 3,3′-dichloro-4,4′-biphenylene diisocyanate, 1,5-naphthalene diisocyanate Sulfonates, 1,5-tetrahydronaphthalene diisocyanate, norbornane diisocyanate methyl, and the like. Among these, it may be used alone or in combination of two or more.

  Examples of the trifunctional or higher functional isocyanate include isocyanurate type polyisocyanate, adduct type polyisocyanate, burette type polyisocyanate obtained by trimerizing diisocyanate generally used, and 1-methylbenzole-2,4,6-triisocyanate. Isocyanate, 1,3,5-trimethylbenzole-2,4,6-triisocyanate, biphenyl-2,4,4'-triisocyanate, diphenylmethane-2,4,4'-triisocyanate, methyldiphenylmethane-4,6 , 4'-triisocyanate, 4,4'-dimethyldiphenylmethane-2,2 ', 5,5'-tetraisocyanate, triphenylmethane-4,4', 4 "-triisocyanate, polymeric MDI (diphenylmethane di. Isocyanate) . Of these, it is used in only one kind, or two or more kinds may be used in combination.

In the polymer component derived from the mixture contained in the spherical particles, the amount of the polyfunctional isocyanate contained in the mixture is 10 to 400 parts by weight. Preferably, it is 15 to 300 parts by weight. When the amount of polyfunctional isocyanate contained in the mixture is less than 10 parts by weight, the touch of urethane may not be obtained. On the other hand, when the amount is more than 400 parts by weight, the solvent resistance of the spherical particles may be lowered, and it may be difficult to obtain the spherical particles as primary particles.
In addition, the content of the polymer component derived from the vinyl monomer, the polyfunctional radical polymerizable monomer and the polyfunctional isocyanate mixture in the spherical particles is almost equal to the usage amount of the corresponding monomer. .

  In the present invention, since the non-reactive organic solvent for dilution is not used in the production process of the spherical particles, the obtained spherical particles are substantially free of the non-reactive organic solvent. If a non-reactive organic solvent is included, it is considered that it is derived from the raw material procured for producing spherical particles (the one used at the time of production). The fact that the obtained spherical particles do not substantially contain a non-reactive organic solvent is based on a gas chromatograph with a headspace sampler (manufactured by HTA: headspace autosampler HT200H, manufactured by Shimadzu Corporation: gas chromatograph GC-18A). The concentration measurement value of the non-reactive organic solvent is indicated by being 1 ppm or less (which is a detection limit value).

  As a method for polymerizing the polymerizable composition for obtaining spherical urethane resin particles, a known polymerization method such as a suspension polymerization method, an emulsion polymerization method, a dispersion polymerization method, or the like can be used. Hereinafter, although an example of the manufacturing method of the spherical urethane-type resin particle by suspension polymerization method is demonstrated, this invention is not limited only to this manufacturing method.

  A polymerizable composition is obtained by adding and mixing a vinyl monomer containing an active hydrogen (meth) acrylate monomer, a polyfunctional isocyanate, a radical polymerization initiator, a urethane curing catalyst, and optionally other monomers. . The obtained polymerizable composition is suspended in an aqueous dispersion medium. Here, it is preferable to use 100 to 2000 parts by weight of the aqueous dispersion medium with respect to 100 parts by weight of the polymerizable composition. In addition, as an aqueous dispersion medium, the mixture of water or water and a water-soluble solvent (for example, lower alcohol) is mentioned.

  The suspension stabilizer is preferably added to the aqueous dispersion medium before the addition of the polymerizable composition. Suspension polymerization can be performed by heating an aqueous dispersion medium to a temperature of, for example, 40 to 100 ° C, preferably 45 to 90 ° C. After the suspension polymerization is completed, the obtained urethane resin particles are separated from the aqueous dispersion medium, washed and dried, and then subjected to a classification step as necessary to obtain spherical urethane resin particles having a desired particle size. Can do.

  The suspension stabilizer is not limited as long as the desired spherical urethane resin particles can be obtained. For example, a polymeric stabilizer such as polyvinyl alcohol, tribasic calcium phosphate, hydroxyapatite, Examples include slightly water-soluble inorganic salts such as magnesium pyrophosphate, calcium pyrophosphate, calcium phosphate, magnesium phosphate, and magnesium carbonate. Among them, it is preferable to use an inorganic salt that can be easily dissolved and removed by adjusting the pH of the system after the completion of polymerization. For example, it is preferable to use tribasic calcium phosphate, magnesium pyrophosphate or calcium pyrophosphate produced by the metathesis method, because the desired spherical urethane resin particles can be obtained more stably.

  The suspension stabilizer is used by appropriately adjusting the composition and amount of use so that the spherical urethane resin particles obtained have a predetermined particle size. The addition amount of the suspension stabilizer is preferably 0.05 to 30 parts by weight with respect to 100 parts by weight of the polymerizable composition. More preferably, it is 0.1-20 weight part.

  The radical polymerization initiator is not particularly limited. For example, benzoyl peroxide, lauroyl peroxide, benzoyl peroxide, benzoyl orthomethoxy peroxide, 3,5,5-trimethylhexanoyl peroxide, t -Organic peroxides such as butylperoxy-2-ethylhexanoate and di-t-butylperoxide, azobisisobutyronitrile, azobiscyclohexacarbonitrile, 2,2'-azobis (2,4 -Azo-based compounds such as dimethylvaleronitrile). The addition amount of the radical polymerization initiator is preferably 0.1 to 20 parts by weight with respect to 100 parts by weight of the polymerizable composition. In particular, 0.3 to 5 parts by weight is preferable.

  The urethane curing catalyst is not particularly limited, and examples thereof include DBU [1,8-diazabicyclo (5.4.0) undecene-7], DBU phenol salt, DBU octylate, DBU formate and the like. DBU, monoamine (such as triethylamine), diamine (such as N, N, N ′, N′-tetramethylethylenediamine), triamine (such as tetramethylguanidine), cyclic amine (such as triethylenediamine), alcohol amine (such as dimethylaminomethanol) ), Amine amines such as ether amine [bis (2-dimethylaminoethyl) ether, etc.], Sn-based (dibutyltin dilaurate, tin octylate, etc.), Pb-based (lead octylate, etc.), Zn-based (zinc octylate, etc.) ), Ti-based (titanium octylate, titanium tetrabutoxide, titanium acetylacetone) Rate, etc.), Zr-based (stearate, zirconium tetrapropoxide, zirconium acetylacetonate chelate) organometallic compounds such as 2-methylimidazole, imidazole such as 1,2-dimethyl imidazole.

  It is preferable that the addition amount of a urethane curing catalyst is 0.001-50 weight part with respect to 100 weight part of polyfunctional isocyanate. More preferably, it is 0.01 to 10 parts by weight. If the addition amount is less than 0.001 part by weight, the addition reaction may not be promoted. On the other hand, if it exceeds 50 parts by weight, the particle size may not be easily adjusted because the polymerization reaction cannot be easily controlled in a subsequent polymerization step (such as suspension polymerization).

  Surfactants such as an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant may be added to the aqueous dispersion medium. The addition amount of the surfactant is preferably 0.002 to 10 parts by weight with respect to 100 parts by weight of the polymerizable composition. More preferably, it is 0.005 to 5 parts by weight.

  Examples of anionic surfactants include fatty acid oils such as sodium oleate and castor oil potassium, alkyl sulfate salts such as sodium lauryl sulfate and ammonium lauryl sulfate, alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate, and alkylnaphthalene sulfonates. , Alkane sulfonate, dialkyl sulfosuccinate, naphthalene sulfonic acid formalin condensate, polyoxyethylene alkyl phenyl ether sulfate, polyoxyethylene alkyl sulfate, and the like.

Examples of the cationic surfactant include alkylamine salts such as laurylamine acetate and stearylamine acetate, and quaternary ammonium salts such as lauryltrimethylammonium chloride.
Examples of the zwitterionic surfactant include lauryl dimethylamine oxide and phosphate ester or phosphite ester surfactants.
Nonionic surfactants include, for example, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxysorbitan fatty acid ester, polyoxyethylene alkylamine, glycerin fatty acid ester, oxy Examples include ethylene-oxypropylene block polymers.

  In order to suppress the generation of emulsified particles in the aqueous system in the polymerization step, water-soluble polymerization inhibitors such as nitrites, sulfites, hydroquinones, ascorbic acids, water-soluble vitamin Bs, citric acid, polyphenols, etc. May be used.

  After the polymerization is completed, the spherical urethane-based resin particles are centrifuged as necessary to remove the aqueous medium, washed with water and a solvent, and then dried and isolated. The method for isolating the spherical urethane-based resin particles obtained from the aqueous dispersion medium by suspension polymerization performed in the present invention is not particularly limited, but as a known method, for example, a spray represented by a spray dryer. Examples thereof include a drying method, a method of attaching to a heated rotating drum typified by a drum dryer, and a freeze drying method.

  The resulting spherical urethane-based resin particles have moderate hardness, elasticity and soft feel, and there is no deterioration in quality because no non-reactive organic solvent is used as a diluting solvent. Such particles can be suitably used as organic fillers in applications such as light diffusion films, cosmetic additives, paints, plastics, and adhesives. Further, the thermoplastic type urethane resin particles can be suitably used as a hot melt adhesive.

  Spherical urethane resin particles obtained by the above production method or other production methods have a phase separation structure of a phase made of a vinyl polymer and a phase made of a urethane polymer in the particles. This structure includes a sea-island structure composed of a matrix phase that is the main component in the particles and a dispersed phase present in the matrix phase, and a cross-laminated structure such as a formation. The vinyl polymer and the urethane polymer can be in a matrix phase and a dispersed phase, respectively. Each phase may be a polymer alone or a mixture with a small amount of the other polymer component. As a form of a sea-island structure composed of a matrix phase and a dispersed phase, there are a shape in which the dispersed phase is present in a spherical shape in the matrix phase (FIG. 2), an irregular shape, and the like.

  The average longest diameter (r) of the dispersed phase is in the range of average particle diameter (R) of spherical urethane resin particles / 500 ≦ (r) <average particle diameter (R) / 10 of spherical urethane resin particles. The longest diameter means that the dispersed phase is not spherical but has an indeterminate shape, or the dispersed phase has an overlapped shape such as a 99-fold shape (the opposite side from the end of the layer to be overlapped) In the case where the distance to the end exceeds the particle diameter), the length at which the linear distance connecting the two points is the maximum between the two points on the contour surface of the dispersed phase is shown.

  Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.

  First, a method for measuring the average particle size, a method for observing the particle cross section, a method for measuring the longest diameter of the dispersed phase in the particles, a method for measuring the strength (S10 strength) of the particles, and a method for measuring the included non-reactive organic solvent will be described. .

(Measurement method of average particle size)
0.1 g of urethane resin particles and 10 ml of a 0.3% aqueous solution of a nonionic surfactant (Kao Co., Ltd .: LEODOL TW-L120) are put into a test tube. This is preliminarily dispersed using a touch mixer (manufactured by Yamato Kagaku: TOUCHMIXER MT-31) and an ultrasonic cleaner (ULTRASONIC CLEANER VS-150). In a beaker filled with ISOTON II (manufactured by Beckman Coulter, Inc .: measurement electrolyte) provided with the main body, this is dropped with a dropper while gently stirring, and the concentration meter reading on the main body screen is adjusted to about 10%. Next, an aperture is set on the body of Coulter Multisizer III (manufactured by Beckman Coulter, Inc .: measuring device), and measurement is performed under a predetermined condition in which Current, Gain, and Polarity are matched to the aperture size. During the measurement, the inside of the beaker is stirred gently to the extent that bubbles do not enter, and the measurement is terminated when 100,000 resin particles are measured. The volume-weighted average diameter (arithmetic average diameter in volume% mode: volume median diameter) is calculated as the average particle diameter of the resin particles. The aperture used has a pore size of 100 μm.

(Particle cross-section observation method)
After embedding urethane resin particles in the epoxy resin, the epoxy resin is cured to produce particle-containing epoxy resin pieces. This particle-containing epoxy resin piece was stained with ruthenium tetroxide, an ultrathin section was prepared, and a cross-section was observed with a transmission electron microscope (H-7600, manufactured by Hitachi, Ltd.) to check for the presence or absence of a phase separation structure. Observe its shape.

(Measurement method of average longest diameter (r) of dispersed phase in particle)
The average longest diameter (r) of the dispersed phase was determined by observing the cross section of any urethane resin particle at a magnification of 500 to 10,000 using a transmission electron microscope (H-7600, manufactured by Hitachi, Ltd.). Twenty major axes are measured, and an average value of these is calculated.

(Measurement method of particle strength (S10 strength))
The compression strength at the time when the particles are displaced by 10% is measured with a micro compression tester (manufactured by Shimadzu Corporation: MCTM200). The measurement procedure and measurement conditions are as follows.
First, resin particles are dispersed in ethanol, and then coated and dried on a mirror-finished steel sample table to prepare a measurement sample.
Next, an independent single particle is selected by an optical microscope attached to MCTM200 in an environment of room temperature 20 ° C. and relative humidity 65%. At this time, the particle condition to be selected is a particle measurement cursor of MCTM200 having a particle diameter in the range of 9 to 11 μm, and particles outside this range are not used for measurement.
Next, the test indenter is lowered to the apex of the selected particles at the following load speed, gradually applied, and added up to a load of 1 g, so that it is displaced by 10% from the previously measured particle diameter. The compressive strength (strength) is obtained from the load. In each of the examples and comparative examples, the measurement is performed six times, and the average value of the remaining four measurement data excluding the two data of the maximum value and the minimum value is taken as the S10 intensity of each example and comparative example.
Test temperature: 20 ° C
Relative humidity: 65%
Test indenter: Flat 50 (flat indenter with a diameter of 50 μm)
Test type: Compression test (MODE1)
Test load: 1.00 gf
Load speed: 0.072500 gf / sec
Displacement full scale: 10 μm

(Measurement method of non-reactive organic solvent contained)
In a 20 ml vial tube, 0.1 g of urethane resin and 1 ml of dimethylformamide solution containing 125 ppm diethylbenzene were added and left for 24 hours. Thereafter, the vial tube was installed in a headspace sampler (manufactured by HTA: HT200H) and heated at 90 ° C. for 1 hour. 2 ml of the air layer in the vial tube is injected into a gas chromatograph (manufactured by Shimadzu Corporation: GC-18A), and the contained nonreactive organic solvent (toluene or the like) is quantified.
Measuring device: Gas chromatograph with headspace sampler (manufactured by HTA: headspace autosampler HT200H, Shimadzu Corporation: gas chromatograph GC-18A)
Column used: ZB-WAX (0.25 μm × 0.25 mmΦ × 30 m) (Phenomenex)
Detector: PID
Measurement conditions: column temperature (60 ° C. for 3 minutes, 20 ° C./minute to 100 ° C., 40 ° C./minute to 220 ° C., 220 ° C. for 30 seconds), inlet temperature (150 ° C.), detection Temperature (250 ° C), column flow rate (1.6 ml / min (using helium gas))

Example 1
(A-1) Production of particles 20 parts by weight of 2-hydroxypropyl methacrylate (active hydrogen (meth) acrylate monomer) is added to 180 parts by weight of butyl acrylate (non-active hydrogen (meth) acrylate monomer) 1 part by weight of ethylene glycol dimethacrylate as a functional radical polymerizable monomer, 200 parts by weight of trifunctional isocyanurate type polyfunctional isocyanate (Duranate ^™ TPA-100 manufactured by Asahi Kasei Co., Ltd.), and 2 azobisvaleronitrile as an initiator 0.05 parts by weight of an organic titanium compound (manufactured by Matsumoto Fine Chemical Co., Ltd .: TC-700) as a urethane curing catalyst was added to prepare a polymerizable composition.
As an aqueous phase, 1000 parts by weight of ion-exchanged water and 35 parts by weight of magnesium pyrophosphate as a suspension stabilizer were added.
The polymerizable composition was placed in this aqueous phase and stirred with a homogenizer at 7000 rpm for 10 minutes. Thereafter, the reaction was carried out in a nitrogen atmosphere at 55 ° C. for 3 hours, and then heated to 100 ° C. for 2 hours. Thereafter, hydrochloric acid was added to dissolve magnesium pyrophosphate, solid-liquid separation, washing, and drying were performed to obtain the desired particles.

(B-1) Evaluation of Particles The particle diameter of the obtained particles was 10 μm. As a result of observing the particles with a scanning electron microscope, the shape of the particles was spherical with no irregularities on the surface. The ratio of the major axis to the minor axis of the particles was 1.0. A phase separation structure was confirmed in the particles, and the dispersed phase was present in a spherical shape in the matrix phase (continuous phase). The longest diameter of the dispersed phase was measured and found to be 0.2 μm. The S10 strength of the particles was 0.36 kgf / mm ² . The residual concentration of the non-reactive organic solvent in the particles was measured and found to be 1 ppm or less.

(Example 2)
(A-2) Production of Particles 100 parts by weight of butyl acrylate, 100 parts by weight of 2-hydroxypropyl methacrylate, 3 parts by weight of ethylene glycol dimethacrylate, trifunctional isocyanurate type polyfunctional isocyanate (manufactured by Asahi Kasei Corporation) Particles were obtained in the same manner as in Example 1 except that 200 parts by weight of Duranate ^™ TPA-100) was used.
(B-2) Evaluation of Particles The particle diameter of the obtained particles was 11 μm. As a result of observing the particles with a scanning electron microscope, the shape of the particles was spherical with no irregularities on the surface. The ratio of the major axis to the minor axis of the particles was 1.0. A phase separation structure was confirmed in the particles, and the dispersed phase was present in a spherical shape in the matrix phase (continuous phase). The longest diameter of the dispersed phase was measured and found to be 0.3 μm. The S10 strength of the particles was 0.53 kgf / mm ² . The residual concentration of the non-reactive organic solvent in the particles was measured and found to be 1 ppm or less.

(Comparative Example 1)
(A-3) Production of Particles 50 parts by weight of butyl acrylate, 50 parts by weight of 2-hydroxypropyl methacrylate, 10 parts by weight of ethylene glycol dimethacrylate, trifunctional isocyanurate type polyfunctional isocyanate (manufactured by Asahi Kasei Corporation) Particles were obtained in the same manner as in Example 1 except that 200 parts by weight of Duranate ^™ TPA-100) was used.
(B-3) Evaluation of Particles The particle diameter of the obtained particles was 13 μm. As a result of observing the particles with a scanning electron microscope, the shape of the particles was an irregular shape having irregularities on the surface. The ratio of the major axis to the minor axis of the particles was 1.0. A phase separation structure was confirmed in the particles, and the dispersed phase was present in a spherical shape in the matrix phase (continuous phase). The longest diameter of the dispersed phase was measured and found to be 0.5 μm. The S10 strength of the particles was 0.32 kgf / mm ² . The residual concentration of the non-reactive organic solvent in the particles was measured and found to be 1 ppm or less.
The results of Examples 1 and 2 and Comparative Example 1 are shown together in Table 1.

AB: butyl acrylate (active hydrogen-free acrylate)
HPA: 2-hydroxypropyl methacrylate (methacrylate containing active hydrogen)
EGDMA: ethylene glycol dimethacrylate ABN-V: azobisvaleronitrile BPO: benzoyl peroxide TPA-100: trifunctional isocyanurate type polyfunctional isocyanate (Duranate ^TM TPA-100 manufactured by Asahi Kasei Corporation)

  The evaluation of Comparative Example 1 is considered to be caused by the use amount of the polyfunctional radical polymerizable monomer being 2 parts by weight or more.

Claims (6)

Polyfunctional radical polymerizable monomer 0.05 parts by weight or more and less than 2.0 parts by weight and polyfunctional isocyanate 10 to 400 parts by weight with respect to 100 parts by weight of vinyl monomer containing active hydrogen (meth) acrylate monomer A spherical urethane-based resin particle comprising a polymer component derived from a mixture containing at a ratio of 1 part, and having a non-reactive organic solvent concentration measured by a gas chromatograph with a headspace sampler of 1 ppm or less .   The spherical urethane-based resin particles according to claim 1, wherein the spherical urethane-based resin particles have a phase separation structure composed of a matrix phase and a dispersed phase present in the matrix phase.   The spherical urethane resin particles according to claim 1 or 2, wherein the active hydrogen (meth) acrylate monomer has one or more hydroxyl groups in the molecule.   The spherical urethane-based resin particles according to any one of claims 1 to 3, wherein the polyfunctional radical polymerizable monomer is composed of a (meth) acrylic acid ester monomer and / or an aromatic monomer. .   The spherical urethane-based resin particles according to any one of claims 1 to 4, wherein the polyfunctional isocyanate is a burette type, isocyanurate type or adduct type isocyanate having three or more isocyanate groups in the molecule.   Polyfunctional radical polymerizable monomer 0.05 parts by weight or more and less than 2.0 parts by weight, polyfunctional isocyanate 10 to 400 parts by weight with respect to 100 parts by weight of vinyl monomer containing active hydrogen (meth) acrylate monomer Polymerization of a polymerizable composition containing a mixture containing a part, a radical polymerization initiator and a urethane curing catalyst in an aqueous medium in the presence of a suspension stabilizer and in the absence of a non-reactive organic solvent. A method for producing spherical urethane resin particles, comprising obtaining spherical urethane resin particles by a step.