JP5661520B2 - Method for producing thermoplastic polyurethane resin powder - Google Patents

Description

The present invention relates to a method for obtaining a thermoplastic polyurethane resin powder having a constant particle size and a sharp particle size distribution.

In recent years, the slush molding method has advantages such as the ability to easily mold products with complex shapes (undercut, deep drawing, etc.), uniform wall thickness, and good material yield. It is widely used for applications centered around.

In the slush molding method, soft polyvinyl chloride powder was mainly used, but in recent years polyurethane resin has also been used. Since the polyurethane resin is synthesized in an organic solvent, it is expensive and environmentally problematic. Recently, a method for producing a urethane resin powder in an aqueous medium has been proposed. (See Patent Documents 1 to 4).

Japanese Patent Laid-Open No. 3-97712 JP-A-8-120041 JP-A-12-313733 WO98-51748

However, in the method of Patent Document 1, when the urethane resin powder forming component is dispersed in water, an emulsifier is contained in the water of the dispersion medium and dispersed with a high shearing disperser. From small particles of several μm to coarse particles of about several mm. If the resin powder obtained from this dispersion is used for slush molding as it is, powder flowability is poor and pinholes etc. are generated on the surface of the molded product, so it is necessary to classify to a particle size distribution suitable for slush molding. However, the method is very lossy, yield is low, and time is required.
In addition, the methods of Patent Documents 2, 3 and 4 have a narrow particle size distribution and improved powder flowability as compared with Patent Document 1, but a small amount of microparticles of several μm and several hundreds. Coarse particles of μm are generated and need to be classified to a particle size distribution suitable for slush molding applications.
An object of the present invention is to provide a method for producing a thermoplastic polyurethane resin powder, which is free from fine particles and coarse particles and is suitable mainly for slush molding, in which the above problems are improved.

As a result of intensive studies to solve the above problems, the present inventors have reached the present invention. That is, the present invention is a thermoplastic polyurethane resin powder (D) having a particle size distribution Cv of 20 to 55, and includes the following step 1 and step 2-2 The manufacturing method of the thermoplastic polyurethane resin powder (D) containing this.
Process 1
The process of manufacturing the thermoplastic polyurethane resin fine powder (G) whose center particle diameter containing a thermoplastic polyurethane resin (A) is 1-100 micrometers.

Step 2-2
An organic solvent (B) having a solubility parameter (SP value) difference of 3.0 or less from the thermoplastic polyurethane resin (A) in the presence of 5 to 30% by weight based on the weight of (G) While stirring at a speed of 0.5 to 50 m / s, (B) is added dropwise and / or sprayed to (G), and the thermoplastic polyurethane resin fine powder (G) is heat-softened to 70 to [(A). A step of granulating by heating to a temperature +10] ° C. and granulating into a thermoplastic polyurethane resin powder (D) by cooling after confirming that the center particle size has reached a certain particle size.

The thermoplastic polyurethane resin powder produced according to the present invention is particularly suitable for slush molding applications, has a particle size distribution Cv of 20 to 55, and has a sharp particle size distribution.

In Step 1, the thermoplastic polyurethane resin (A) is a resin obtained by reacting a high molecular diol, a diisocyanate, and, if necessary, a low molecular diol, a low molecular diamine and the like. The number average molecular weight of (A) is usually 5,000 to 50,000, preferably 10,000 to 30,000.
The measurement conditions of the molecular weight of the thermoplastic polyurethane resin (A) are shown below.
Model: HLC-8220GPC [manufactured by Tosoh Corporation]
Eluent: DMF
Column: Guardcolumn α, TSKgel α-M
Column temperature: 40 ° C
Flow rate: 1 ml / min
Calibration curve sample: polystyrene

Examples of the polymer diol include a polyester diol composed of a combination of glycol and dicarboxylic acid, a polyester diol synthesized from a lactone monomer, a polyether diol, and a polyether ester diol.
From the viewpoint of heat resistance and light resistance, the polymer diol preferably does not contain an ether bond. In particular, polyester diols composed of ethylene glycol and aliphatic dicarboxylic acids having 6 to 15 carbon atoms, aliphatic diols having 4 to 10 carbon atoms and aliphatic dicarboxylic acids having 4 to 15 carbon atoms or aromatic dicarboxylic acids having 8 to 12 carbon atoms. A polyester diol comprising an acid is preferred. Among these, polyethylene adipate, polytetramethylene adipate, polyhexamethylene adipate, and polyhexamethylene isophthalate are preferable.

As the diisocyanate, (i) an aliphatic diisocyanate having 2 to 18 carbon atoms (excluding carbon in the NCO group, the same shall apply hereinafter) [ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 2,2 , 4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2,6-diisocyanatomethylcaproate, bis (2-isocyanatoethyl) fumarate, bis (2-isocyanatoethyl) carbonate, 2-isocyanatoethyl-2, 6-diisocyanatohexanoate etc.]; (ii) alicyclic diisocyanate having 4 to 15 carbon atoms [isophorone diisocyanate (IPDI), dicyclohexylmethane-4,4′-diisocyanate (hydrogenated MDI), Rohexylene diisocyanate, methylcyclohexylene diisocyanate (hydrogenated TDI), bis (2-isocyanatoethyl) -4-cyclohexene, etc.]; (iii) an araliphatic diisocyanate having 8 to 15 carbon atoms [m-and / or p-xylylene diisocyanate (XDI), α, α, α ′, α′-tetramethylxylylene diisocyanate (TMXDI), etc.]; Specific examples of aromatic polyisocyanates include 1,3- and / or 1,4 -Phenylene diisocyanate, 2,4- and / or 2,6-tolylene diisocyanate (TDI), crude TDI, 2,4'- and / or 4,4'-diphenylmethane diisocyanate (MDI), 4,4'-di Isocyanatobiphenyl, 3,3′-dimethyl-4,4′-diisocyanatobiphenyl, 3,3′-dimethyl-4,4′-diisocyanatodiphenylmethane, crude MDI, 1,5-naphthylene diisocyanate, 4,4 ′, 4 ″ -triphenylmethane triisocyanate, m- and p-isocyanatophenyl Sulfonyl isocyanate and the like; (v) modified products of these diisocyanates (diisocyanate modified products having a carbodiimide group, a uretdione group, a uretoimine group, a urea group, etc.), and a mixture of two or more of these. Is an aliphatic diisocyanate or an alicyclic diisocyanate, and particularly preferred are HDI, IPDI, and hydrogenated MDI.

Examples of the low molecular diol include [ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 1,2-alkanediol having 4 to 24 carbon atoms (dodecane-1). Diols having a cyclic group [1,4-bis (hydroxymethyl) cyclohexane, m- or p-xylylene glycol, alkylene oxide adducts of bisphenols, etc.], etc. The combined use of more than seeds is mentioned.

Examples of the diamine include alicyclic diamines having 6 to 18 carbon atoms [4,4′-diamino-3,3′-dimethyldicyclohexylmethane, 4,4′-diaminodicyclohexylmethane, diaminocyclohexane, isophoronediamine, etc.]; 2-12 aliphatic diamines [ethylenediamine, propylenediamine, hexamethylenediamine, etc.]; C8-15 aromatic aliphatic diamines [xylylenediamine, α, α, α ′, α′-tetramethylxylylenediamine, etc. And a mixture of two or more thereof. Of these, alicyclic diamines and aliphatic diamines are preferable, and isophorone diamine and hexamethylene diamine are particularly preferable.

The center particle diameter of the thermoplastic polyurethane resin fine powder (G) is 1 to 100 μm, preferably 5 to 70 μm, and more preferably 10 to 50 μm.
The central particle diameter d here refers to a particle diameter: d50 when the cumulative amount is 50% in a relative cumulative volume average particle diameter distribution curve that can be measured by a laser diffraction particle size distribution measuring apparatus or the like. Shall.
When the raw material fine powder having a center particle diameter exceeding 100 μm is used, the particle size distribution of the produced thermoplastic polyurethane resin powder becomes wide and the powder fluidity is poor. When the raw material having a center particle diameter of less than 1 μm is used, It is not suitable from the viewpoint of powder fluidity and powder scattering.

Examples of the thermoplastic polyurethane resin fine powder (G) include those obtained by the following production method.
A polymer diol and a diisocyanate are reacted to produce an isocyanate group-terminated urethane prepolymer, and then the isocyanate group-terminated urethane prepolymer and a blocked chain extender (eg, a ketimine compound) in the presence of water and a dispersion stabilizer. A method of producing (G) by a reaction method. Specifically, for example, those described in JP-A-8-120041 can be used. The center particle diameter of (G) can be controlled to 1 to 100 μm by the amount of the dispersion stabilizer, the rotational speed of the disperser, and the like.

Although the heat softening temperature of a thermoplastic polyurethane resin (A) is not specifically limited, Preferably it is 100 to 200 degreeC, More preferably, it is 120 to 180 degreeC. By setting the heat softening temperature within the above range, a thermoplastic polyurethane resin powder having excellent heat resistance and heat melting property can be obtained.

Regarding the step 2-1, the granulation temperature is preferably heated to [(A) heat softening temperature −10] to [(A) heat softening temperature +10] ° C., and [(A) heat softening temperature −5]. It is more preferable to heat to [thermal softening temperature of (A) +5] ° C.

Stirring is performed at a peripheral speed of 0.5 to 50 m / s, preferably 8 to 40 m / s during granulation. If the peripheral speed is less than 0.5 m / s, the cohesive force between particles is much larger than the shear force, and the particles become coarse. If the peripheral speed exceeds 50 m / s, the shearing force is very strong and the particle diameter during granulation cannot be controlled. The peripheral speed is preferably 8 to 40 m / s because the powder can be uniformly heated.

If the peripheral speed is 8 m / s or more, heat is generated by frictional heat due to shear. By using this heat and heating and granulating the powder, the amount of deposits on the jacket can be drastically reduced compared to granulation only by heating the jacket.

The granulator is not particularly limited, but an apparatus with good stirring efficiency is preferable. For example, high-speed shear mixing device [Nippon Coke Co., Ltd. “Henschel Mixer”, Fukae Kogyo Co., Ltd. “High Speed Mixer” etc.], low-speed mixing device [Asada Steel Corporation planetary mixer, Hosokawa Micron ( "Nauta mixer" etc. made by Co., Ltd.] etc. are mentioned.

The end point of granulation is determined when the center particle diameter of the thermoplastic polyurethane resin powder (D) obtained while measuring the center particle diameter reaches a certain desired particle diameter.
The certain desired particle size can be selected from a range of preferably 10 to 500 μm.
When the end point is reached, the thermoplastic polyurethane resin powder (D) is immediately cooled to 50 ° C. or lower so that the granulation does not proceed further. The central particle size is measured with a laser diffraction particle size distribution analyzer.

The adding method of the organic solvent (B) in Step 2-2 is not particularly limited, and the thermoplastic polyurethane resin fine powder (G) may be charged all at once before granulation or may be charged separately.
The charging method is preferably dripping and spraying under stirring, and more preferably spraying from the viewpoint of uniformity.

In the organic solvent (B), the difference in solubility parameter (SP value) from the thermoplastic polyurethane resin (A) is 3 or less, preferably 1 or less, and the difference in SP value between (A) and (B) is 3. If it exceeds, granulation does not occur.
The SP value is calculated by the Fedors method.
The SP value can be expressed by the following equation.
SP value (δ) = (ΔH / V) ^1/2
In the formula, ΔH represents the heat of vaporization (cal), and V represents the molar volume (cm 3).
ΔH and V are “POLYMER ENGINEERING AND SCIENCE FEBRUARY, 1974, Vol. 14, No. 2, ROBERT F. FEDORS. (151-153)” and “POLYMER ENGINEERING AND SCIENCE JUNE, 1974, Vol. No. 6, ROBERT F. FEDORS. (Page 472) ", the total heat of molar evaporation (ΔH) of the atomic group and the total molar volume (V) can be used.
Those having a close numerical value are easy to mix with each other (high compatibility), and those having a close numerical value are indices that indicate that they are difficult to mix.

The SP value of the thermoplastic polyurethane resin (A) is preferably 8-12.
Examples of the organic solvent (B) having a SP value difference of 3 or less from (A) include ketones, alcohols, ethers, esters, and combinations of two or more thereof. Preferably, it is at least one selected from the group consisting of ketones having 3 to 9 carbon atoms, ethers having 4 to 8 carbon atoms, and esters having 3 to 6 carbon atoms, and combinations of two or more thereof.

Examples of the ketone having 3 to 9 carbon atoms include acetone, methyl ethyl ketone (hereinafter referred to as MEK), methyl isobutyl ketone (hereinafter referred to as MIBK), and diethyl ketone. Examples of the ether having 4 to 8 carbon atoms include tetrahydrofuran (hereinafter THF). Examples of the ester having 3 to 6 carbon atoms include methyl acetate and ethyl acetate. Acetone, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran and ethyl acetate are preferred.

The amount of the organic solvent (B) added is 5 to 30% by weight, preferably 10 to 25% by weight, based on the thermoplastic polyurethane resin fine powder (G). When the addition amount is less than 5% by weight, the adhesion strength between the particles is weak and granulation does not occur. When the addition amount exceeds 30% by weight, it becomes a paste and coarse particles are generated during granulation, and the particle size distribution becomes wide.

The granulation temperature when the organic solvent (B) is sprayed can be lower than that when the organic solvent (B) is not sprayed. The granulation temperature is preferably 70 ° C. to [thermal softening temperature + 10] ° C., more preferably 80 ° C. to [thermal softening temperature + 5] ° C.

The peripheral speed at the time of granulation is a peripheral speed of 0.5 to 50 m / s, preferably 5 to 40 m / s. If the peripheral speed is less than 0.5 m / s, the cohesive force between particles is much larger than the shear force, and the particles become coarse. If the peripheral speed exceeds 50 m / s, the shearing force is very strong and the particle diameter during granulation cannot be controlled.
The granulator is not particularly limited, but an apparatus with good stirring efficiency is preferable. For example, high-speed shear mixing device [Nippon Coke Co., Ltd. “Henschel Mixer”, Fukae Kogyo Co., Ltd. “High Speed Mixer” etc.], low-speed mixing device [Asada Steel Corporation planetary mixer, Hosokawa Micron ( "Nauta mixer" etc. made by Co., Ltd.].

The end point of granulation can be performed in the same manner as in Step 2-1.

Granulation of the thermoplastic polyurethane resin powder (D) in the presence of fine particle powder (P) having a center particle diameter of 0.1 to 10 μm and not softened at the granulation temperature is fluidity during granulation. Is preferable in that a thermoplastic polyurethane resin powder having a sharp particle size distribution can be obtained.
The addition of (P) may be performed in either step 1 or step 2, but when heated and granulated in the above steps 2-1 and 2-2, (P) is a thermoplastic polyurethane resin fine powder. It is preferable to add to the body (G).
The addition amount of (P) is preferably 0 to 5% by weight, more preferably 0.1 to 1.0% by weight based on the weight of (G). The center particle diameter of the fine particle powder (P) is preferably 0.1 to 10 μm, and more preferably 0.5 to 3.0 μm.
Specifically, (P) does not soften at the granulation temperature, specifically, the thermal softening point of (P) is [granulation temperature + 5] ° C. or more.

Specific examples of (P) include resin particles (P1) and inorganic particles (P2).
(P1) includes maleimide resin particles, vinyl chloride resin fine particles, polyacrylonitrile resin fine particles, poly (meth) acrylate resin fine particles, polystyrene resin fine particles, polyethylene resin fine particles, polypropylene resin fine particles, polyester resin fine particles. And polyamide-based resin fine particles. These resins preferably have a crosslinked structure. Among these, as the resin particles (P1), maleimide resin particles and poly (meth) acrylate resin particles are preferable, and maleimide copolymer particles and crosslinked polymethyl methacrylate resin particles are more preferable. As the maleimide copolymer, maleimide copolymer particles obtained by crosslinking a copolymer of N-cyclohexylmaleimide and 2-hydroxyethyl (meth) acrylate with hexamethylene diisocyanate and / or isophorone diisocyanate are more preferable. The crosslinked polymethyl methacrylate resin is more preferably a crosslinked product of a methyl methacrylate / ethylene glycol dimethacrylate copolymer.

As inorganic particles (P2), silica particles, talc, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, iron oxide, copper oxide, zinc oxide, tin oxide, silica sand, clay , Mica, wollastonite, diatomaceous earth, chromium oxide, cerium oxide, pengala, antimony trioxide, magnesium oxide, zirconium oxide, aluminum oxide, parium sulfate, barium carbonate, calcium carbonate, silicon carbide, silicon nitride, and these Examples include hydrophobized ones.
Among these, silica particles, talc, and aluminum oxide are preferable as the inorganic particles (P2).

As a method for removing the remaining organic solvent (B) after granulation, a known method (such as desolvation) may be mentioned.
Examples of the removing method include a method of removing by heating under reduced pressure or normal pressure while stirring. However, if it is heated at a temperature of 70 ° C. or higher, it is granulated, so the heating temperature must be 70 ° C. or lower.

The thermoplastic polyurethane resin powder (D) of the present invention thus obtained has a particle size distribution Cv of 20 to 55 and a sharp particle size distribution over a wide particle size range. The center particle size of (D) is preferably 10 to 500 μm from the viewpoint of easy control of the particle size distribution Cv.

The center particle diameter of the resin particles of the thermoplastic polyurethane resin powder (D) obtained by the method of the present invention is preferably 10 to 500 μm. However, in order to sufficiently exhibit the effects of the present invention, preferred center particles The diameter d is 10 μm ≦ d ≦ 300 μm, more preferably 100 μm ≦ d ≦ 300 μm.

The particle size distribution Cv here is defined as follows.
In a relative cumulative volume average particle size distribution curve that can be measured by a laser diffraction type particle size distribution measuring device or the like, d50 is the particle size when the cumulative amount is 50%, and SD is the standard deviation.
Cv = 100 × SD / d50

Since the thermoplastic polyurethane resin powder (D) of the present invention has a very sharp particle size distribution, it exhibits excellent performance such as high powder flowability and uniform coating film formation.

In the thermoplastic polyurethane resin powder (D) obtained by the production method of the present invention, known additives (pigments, dyes, mold release agents, lubricants, plasticizers, antiblocking agents, coupling agents, Weathering stabilizers, heat resistance stabilizers, flame retardants, etc.) may be included. The amount of these additives to be used is appropriately selected in the range of usually 0 to 40% by mass on the basis of mass with respect to (D) in consideration of the purpose of use and effects. The additive may be previously contained in the dispersion medium in the stage before granulation, or may be added after dispersion. Further, it may be added to (D) and mixed with powder.

The thermoplastic polyurethane resin powder obtained by the method of the present invention preferably has a center particle size of 10 to 500 μm, a particle size distribution Cv of 20 to 55, good powder flowability, and a core. Although it can be suitably used for ground adhesives, suede-like paints, hot melt adhesives, powder paints, slush molding materials, various fillers, spacers, toners, etc., it is particularly suitable for slush molding materials.

EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited to this. In the following description, “parts” represents parts by weight and “%” represents% by weight.

Production Example 1
Production of MEK ketimine product of diamine (K-1)
Hexamethylenediamine and excess MEK (4-fold molar amount with respect to the diamine) were refluxed at 80 ° C. for 24 hours, and the produced water was removed from the system. Thereafter, unreacted MEK was removed under reduced pressure to obtain a MEK ketiminate.

Production Example 2
Production of polyethylene phthalate having a number average molecular weight (hereinafter referred to as Mn) of 900 (terephthalic acid / isophthalic acid = 50/50) (D1-1) In a reaction vessel equipped with a cooling pipe, a stirrer and a nitrogen introducing pipe, 393 parts of acid, 393 parts of isophthalic acid, and 606 parts of monoethylene glycol were allowed to react for 5 hours while distilling off the water produced under a nitrogen stream at 210 ° C., and then reacted under a reduced pressure of 5 to 20 mmHg. Polyethylene phthalate diol (D1-1) was taken out at a softening point of. The recovered monoethylene glycol was 245 parts. It was 900 as a result of measuring the hydroxyl value of the obtained polyethylene phthalate diol, and calculating Mn.
Production of polyethylene phthalate diol (D1-2) with Mn of 2500 By adjusting the pressure reduction time by the same production method, polyethylene phthalate diol (D1-2) with Mn of 2500 was obtained. The recovered monoethylene glycol was 270 parts.

Production Example 3
Preparation of prepolymer solution (U-1) In a reaction vessel equipped with a thermometer, stirrer and nitrogen blowing tube, polyethylene phthalate diol (D1-2) (304 parts), polybutylene adipate with Mn of 1000 (1214 parts) ), 1-octanol (27.6 parts) was charged and purged with nitrogen, then heated to 110 ° C. with stirring and melted, and cooled to 60 ° C. Subsequently, hexamethylene diisocyanate (313.2 parts) was added and reacted at 85 ° C. for 6 hours. Next, after cooling to 60 ° C., tetrahydrofuran (317 parts) and a stabilizer (2.7 parts) [Irganox 1010 manufactured by Ciba Specialty Chemicals Co., Ltd.] and carbon black (1 part) were added uniformly. By mixing, a prepolymer solution (U-1) was obtained. The NCO content of the obtained prepolymer solution was 0.8%.

Production Example 4
Production of Prepolymer Solution (U-2) In a reaction vessel equipped with a thermometer, a stirrer and a nitrogen blowing tube, polybutylene adipate (497.9 parts) having a number average molecular weight (hereinafter referred to as Mn) of 1000, Polyhexamethylene isophthalate with Mn of 900 (124.5 parts), pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] [manufactured by Ciba Specialty Chemicals Co., Ltd. Irganox 1010] (1.12 parts), kaolin (90.7 parts) having a volume average particle size of 9.2 μm were charged, and after nitrogen substitution, the mixture was heated to 110 ° C. with stirring and melted to 60 ° C. Cooled down. Subsequently, 1-octanol (9.7 parts), hexamethylene diisocyanate (153.4 parts), tetrahydrofuran (125 parts), 2- (2H-benzotriazol-2-yl) -6- (linear and side chain dodecyl) ) -4-methylphenol [manufactured by Ciba Specialty Chemicals Co., Ltd .; Tinuvin 571] (2.22 parts), TMXDI polycarbodiimide (C-1) [Mn 15,000, terminal group: methoxy group, properties: 70 % Methyl ethyl ketone (hereinafter referred to as MEK) solution, manufactured by Nisshinbo Industries, Inc .; Carbolite V-09B] (2.15 parts) was added and reacted at 85 ° C. for 6 hours to obtain a prepolymer solution (U-2). . The NCO content of (U-2) was 2.05%.

Production Example 5
Production of Dispersion Medium (Y-1) Dispersant containing Na salt of copolymer of diisobutylene and maleic acid as a dispersant [Sansu Pearl PS-8 manufactured by Sanyo Chemical Industries Ltd.] in 980 parts of water Dissolved and temperature-controlled at 25 ° C. to obtain a dispersion medium (Y-1).

Reference example 1
4. Production of thermoplastic polyurethane resin fine powder (G-1) In a reaction vessel, 100 parts of the prepolymer solution (U-1) obtained in Production Example 3 and the MEK ketimine compound (K-1) obtained in Production Example 1. 6 parts were added, and 340 parts by weight of the dispersion medium (Y-1) obtained in Production Example 5 was added thereto, and a rotational speed of 9000 rpm (peripheral speed: 15 m / s) using an ultradisperser manufactured by Yamato Scientific Co., Ltd. ) For 1 minute. This mixture was transferred to a reaction vessel equipped with a thermometer, a stirrer and a nitrogen blowing tube, purged with nitrogen, and then reacted at 50 ° C. for 10 hours with stirring. After completion of the reaction, the solvent was removed by heating to 60 ° C. under reduced pressure. After removal of the solvent, filtration and drying were performed to produce a thermoplastic polyurethane resin fine powder (G-1).
The center particle size of (G-1) was 22 μm, Cv = 70, SP value 11.2 of thermoplastic polyurethane resin (A-1), and thermal softening temperature 141 ° C.

Production of thermoplastic polyurethane resin powder (D-1) 200 parts of (G-1) prepared above were stirred with a Henschel mixer manufactured by Nippon Coke Co., Ltd. at a peripheral speed of 38.0 m / s. After the temperature was raised to 136 ° C., it was immediately cooled to 55 ° C. with stirring at a peripheral speed of 2.0 m / s. When the center particle diameter was measured, the center particle diameter was 112 μm, so the temperature was raised again and continued at 136 ° C. for 3 minutes. Thereafter, it was immediately cooled to 50 ° C. with stirring at a peripheral speed of 2.0 m / s. When the center particle diameter was measured, the center particle diameter was 152 μm, and thus the mixture was further cooled to 30 ° C. to obtain a thermoplastic polyurethane resin powder (D-1). The obtained (D-1) had a center particle size of 152 μm and Cv = 22.

Reference example 2
4. Production of thermoplastic polyurethane resin fine powder (G-2) In a reaction vessel, 100 parts of the prepolymer solution (U-1) obtained in Production Example 3 and MEK ketiminate (K-1) obtained in Production Example 1 6 parts were added, and 340 parts by weight of the dispersion medium (Y-1) obtained in Production Example 5 was added thereto, and rotation speed of 7000 rpm (circumferential speed: 12 m / s) using an ultradisperser manufactured by Yamato Scientific Co., Ltd. ) For 2 minutes. This mixture was transferred to a reaction vessel equipped with a thermometer, a stirrer and a nitrogen blowing tube, purged with nitrogen, and then reacted at 50 ° C. for 10 hours with stirring. After completion of the reaction, the solvent was removed by heating to 60 ° C. under reduced pressure. After removal of the solvent, filtration and drying were performed to produce a thermoplastic polyurethane resin fine powder (G-2).
The average particle size of (G-2) was 55 μm, Cv = 68, thermoplastic polyurethane resin (A-2) SP value 11.2, and thermal softening temperature 142 ° C.

Production of thermoplastic polyurethane resin powder (D-2) 200 parts of (G-2) prepared above were stirred with a planetary mixer manufactured by Asada Steel Co., Ltd. at a peripheral speed of 0.5 m / s. After the temperature was raised to 148 ° C., it was immediately cooled to 45 ° C. with stirring at a peripheral speed of 0.5 m / s. When the center particle diameter was measured, the center particle diameter was 183 μm, and thus the mixture was further cooled to 30 ° C. to obtain a thermoplastic polyurethane resin powder (D-2). The obtained (D-2) had a center particle size of 183 μm and Cv = 26.

Reference example 3
4. Production of thermoplastic polyurethane resin fine powder (G-3) In a reaction vessel, 100 parts of the prepolymer solution (U-1) obtained in Production Example 3 and the MEK ketimine compound (K-1) obtained in Production Example 1. 6 parts were added, 500 parts by weight of the dispersion medium (Y-1) obtained in Production Example 5 was added thereto, and the number of revolutions at 9000 rpm (peripheral speed: 15 m / s) using an ultradispers manufactured by Yamato Scientific Co., Ltd. ) For 1 minute. This mixture was transferred to a reaction vessel equipped with a thermometer, a stirrer and a nitrogen blowing tube, purged with nitrogen, and then reacted at 50 ° C. for 10 hours with stirring. After completion of the reaction, the solvent was removed by heating to 60 ° C. under reduced pressure. After removal of the solvent, filtration and drying were performed to produce a thermoplastic polyurethane resin fine powder (G-3).
The center particle size of (G-3) was 10 μm, Cv = 60, thermoplastic polyurethane resin (A-3) SP value 11.2, and thermal softening temperature 140 ° C.

Production of Thermoplastic Polyurethane Resin Powder (D-3) To 100 parts of (G-3) prepared above, methyl methacrylate / ethylene glycol dimethacrylate copolymer [Gantz Kasei ); Stafroid PM-030S] was added under stirring and homogenized, and then the mixture was homogenized with a high-speed mixer manufactured by Fukae Kogyo Co., Ltd. at a peripheral speed of 15.0 m / s, 141 After raising the temperature to 0 ° C., it was immediately cooled to 50 ° C. with stirring at a peripheral speed of 1.0 m / s. When the center particle diameter was measured, the center particle diameter was 172 μm, and thus the mixture was further cooled to 30 ° C. to obtain a thermoplastic polyurethane resin powder (D-3). The obtained (D-3) had a center particle size of 172 μm and Cv = 21.

Reference example 4
4. Production of thermoplastic polyurethane resin fine powder (G-4) In a reaction vessel, 100 parts of the prepolymer solution (U-1) obtained in Production Example 3 and the MEK ketimine compound (K-1) obtained in Production Example 1. 6 parts was added, 500 parts by weight of the dispersion medium (Y-1) obtained in Production Example 5 was added thereto, and the rotational speed (circumferential speed: 12 m / s) at 7000 rpm using an ultradisperser manufactured by Yamato Scientific Co., Ltd. ) For 1 minute. This mixture was transferred to a reaction vessel equipped with a thermometer, a stirrer and a nitrogen blowing tube, purged with nitrogen, and then reacted at 50 ° C. for 10 hours with stirring. After completion of the reaction, the solvent was removed by heating to 60 ° C. under reduced pressure. After removal of the solvent, filtration and drying were performed to produce a thermoplastic polyurethane resin fine powder (G-3).
The center particle size of (G-3) was 42 μm, Cv = 66, thermoplastic polyurethane resin (A-4) SP value 11.2, and thermal softening temperature 142 ° C.

Production of Thermoplastic Polyurethane Resin Powder (D-4) 100 parts of (G-4) prepared as described above, and further silica particles (Grace Japan Co., Ltd .; Cybloc S200) as fine particle powder (P) After stirring, 1.0 part was added and homogenized, and the temperature was raised to 145 ° C. while stirring at a peripheral speed of 15.0 m / s with a high-speed mixer manufactured by Fukae Industry Co., Ltd. It cooled to 50 degreeC under 1.0 m / s stirring. When the center particle diameter was measured, the center particle diameter was 213 μm, and the mixture was further cooled to 30 ° C. to obtain a thermoplastic polyurethane resin powder (D-4). The obtained (D-4) had a center particle size of 213 μm and Cv = 26.

Example 5
4. Production of thermoplastic polyurethane resin fine powder (G-5) In a reaction vessel, 100 parts of the prepolymer solution (U-1) obtained in Production Example 3 and the MEK ketimine compound (K-1) obtained in Production Example 1. 6 parts was added, 500 parts by weight of the dispersion medium (Y-1) obtained in Production Example 5 was added thereto, and the rotational speed (circumferential speed: 20 m / s) at 12000 rpm using an ultradisperser manufactured by Yamato Scientific Co., Ltd. ) For 1 minute. This mixture was transferred to a reaction vessel equipped with a thermometer, a stirrer and a nitrogen blowing tube, purged with nitrogen, and then reacted at 50 ° C. for 10 hours with stirring. After completion of the reaction, the solvent was removed by heating to 60 ° C. under reduced pressure. After removal of the solvent, filtration and drying were performed to produce a thermoplastic polyurethane resin fine powder (G-5).
The center particle size of (G-5) was 7 μm, Cv = 91, thermoplastic polyurethane resin (A-5) SP value 11.2, and thermal softening temperature 137 ° C.

Production of thermoplastic polyurethane resin powder (D-5) To 100 parts of (G-5) prepared above, MEK (boiling point: 78 ° C., polyurethane resin (A-2) as solvent (B-1) and The SP value difference of 2.2) was added dropwise with stirring to 5 parts, and the mixture was homogenized. After warming, it was immediately cooled to 50 ° C. with stirring at a peripheral speed of 1.0 m / s. When the center particle diameter was measured, the center particle diameter was 50 μm, and thus 5 parts of MEK was further sprayed, heated to 81 ° C. and continued for 15 minutes, and immediately under stirring at a peripheral speed of 1.0 m / s, Cooled to 50 ° C. When the center particle diameter was measured, the center particle diameter was 103 μm. Therefore, the temperature was raised to 55 ° C., the solvent was distilled off under reduced pressure, and a thermoplastic polyurethane resin powder (D-5) was obtained. The obtained (D-5) had a center particle size of 103 μm and Cv = 34.

Example 6
4. Production of thermoplastic polyurethane resin fine powder (G-6) In a reaction vessel, 100 parts of the prepolymer solution (U-1) obtained in Production Example 3 and MEK ketimine compound (K-1) obtained in Production Example 1. 6 parts was added, and 340 parts by weight of the dispersion medium (Y-1) obtained in Production Example 5 was added thereto, and a rotational speed of 2000 rpm (circumferential speed: 3 m / s) using an ultradisperser manufactured by Yamato Scientific Co., Ltd. ) For 1 minute. This mixture was transferred to a reaction vessel equipped with a thermometer, a stirrer and a nitrogen blowing tube, purged with nitrogen, and then reacted at 50 ° C. for 10 hours with stirring. After completion of the reaction, the solvent was removed by heating to 60 ° C. under reduced pressure. After removing the solvent, filtration and drying were carried out to produce a thermoplastic polyurethane resin powder (G-6).
The average particle size of (G-6) was 98 μm, Cv = 82, SP value 11.2 of thermoplastic polyurethane resin (A-6), and thermal softening temperature 145 ° C.

Production of Thermoplastic Polyurethane Resin Powder (D-6) 100 parts of (G-6) prepared above were mixed with MIBK (boiling point 118 ° C., polyurethane resin (A-2) as solvent (B-1). The difference in value 2.5) was sprayed with 15 parts under stirring and homogenized, and then heated to 105 ° C. with stirring at a peripheral speed of 9.7 m / s using a high-speed mixer manufactured by Fukae Kogyo Co. Thereafter, the mixture was immediately cooled to 55 ° C. with stirring at a peripheral speed of 1.5 m / s. When the center particle diameter was measured, the center particle diameter was 200 μm, so that 10 parts of MIBK was further sprayed, the temperature was raised again, and the temperature was continued at 105 ° C. for 1 hour. Thereafter, it was immediately cooled to 50 ° C. with stirring at a peripheral speed of 1.5 m / s. When the center particle diameter was measured, the center particle diameter was 448 μm. Therefore, the temperature was raised to 65 ° C., the solvent was distilled off under reduced pressure, and a thermoplastic polyurethane resin powder (D-6) was obtained. The obtained (D-6) had an average particle size of 448 μm and Cv = 52.

Example 7
5. Production of thermoplastic polyurethane resin fine powder (G-7) In a reaction vessel, 120 parts of prepolymer solution (U-2) obtained in Production Example 4 and MEK ketimine compound (K-1) obtained in Production Example 1. 2 parts were added, and 400 parts by weight of the dispersion medium (Y-1) obtained in Production Example 5 was added thereto, and a rotational speed of 10,000 rpm (circumferential speed: 17 m / s) using an ultradisperser manufactured by Yamato Scientific Co., Ltd. ) For 3 minutes. This mixture was transferred to a reaction vessel equipped with a thermometer, a stirrer, and a nitrogen blowing tube, purged with nitrogen, and then reacted at 60 ° C. for 10 hours with stirring. After completion of the reaction, the solvent was removed by heating to 70 ° C. under reduced pressure. After removing the solvent, filtration and drying were performed to produce a thermoplastic polyurethane resin powder (G-7).
The average particle size of (G-7) was 3 μm, Cv = 120, thermoplastic polyurethane resin (A-7) SP value 10.7, and thermal softening temperature 125 ° C.

Production of Thermoplastic Polyurethane Resin Powder (D-7) 100 parts of (G-7) prepared above were mixed with acetone (boiling point 56 ° C., polyurethane resin (A-2) as solvent (B-1). After spraying 11 parts of the difference 1.6) under stirring and homogenizing, the temperature was raised to 72 ° C. with stirring at a peripheral speed of 3.7 m / s using a Henschel mixer manufactured by Nippon Coke Co., Ltd. Thereafter, it was immediately cooled to 35 ° C. with stirring at a peripheral speed of 2.0 m / s. When the center particle diameter was measured, the center particle diameter was 18 μm. Therefore, the temperature was raised to 40 ° C., and the solvent was distilled off under reduced pressure to obtain a thermoplastic polyurethane resin powder (D-7). The obtained (D-7) had an average particle size of 18 μm and Cv = 49.

Example 8
5. Production of thermoplastic polyurethane resin fine powder (G-8) In a reaction vessel, 120 parts of the prepolymer solution (U-2) obtained in Production Example 4 and the MEK ketimine compound (K-1) obtained in Production Example 1. 2 parts were added, and 210 parts by weight of the dispersion medium (Y-1) obtained in Production Example 5 was added thereto, and a rotation speed of 9000 rpm (peripheral speed: 15 m / s) using an ultradisperser manufactured by Yamato Scientific Co., Ltd. ) For 1 minute. This mixture was transferred to a reaction vessel equipped with a thermometer, a stirrer and a nitrogen blowing tube, purged with nitrogen, and reacted at 55 ° C. for 8 hours with stirring. After completion of the reaction, the solvent was removed by heating to 80 ° C. under reduced pressure. After removal of the solvent, filtration and drying were performed to produce a thermoplastic polyurethane resin fine powder (G-8).
The average particle size of (G-8) was 37 μm, Cv = 69, SP value 10.7 of thermoplastic polyurethane resin (A-8), and heat softening temperature 130 ° C.

Production of Thermoplastic Polyurethane Resin Powder (D-8) 150 parts of (G-8) prepared above were mixed with MEK (boiling point 78 ° C., polyurethane resin (A-2)) as solvent (B-1). 30 parts of the difference in value 1.7) was added dropwise with stirring, and the mixture was homogenized, and then heated to 76 ° C. with stirring at a peripheral speed of 2.0 m / s using a planetary mixer manufactured by Asada Steel Corporation. Thereafter, it was immediately cooled to 58 ° C. When the center particle diameter was measured, the center particle diameter was 95 μm, so the temperature was raised again and continued at 76 ° C. for 2 hours. Then, it cooled immediately to 50 degreeC. When the center particle diameter was measured, the center particle diameter was 152 μm. Therefore, the temperature was raised to 65 ° C., the solvent was distilled off under reduced pressure, and a thermoplastic polyurethane resin powder (D-8) was obtained. The obtained (D-8) had an average particle size of 152 μm and Cv = 29.

Example 9
5. Production of thermoplastic polyurethane resin fine powder (G-9) In a reaction vessel, 120 parts of the prepolymer solution (U-2) obtained in Production Example 4 and the MEK ketimine compound (K-1) obtained in Production Example 1. 2 parts were added, 200 parts by weight of the dispersion medium (Y-1) obtained in Production Example 5 was added thereto, and the rotation speed at 2500 rpm (circumferential speed: 4 m / s) using an ultradisperser manufactured by Yamato Scientific Co., Ltd. ) For 1 minute. This mixture was transferred to a reaction vessel equipped with a thermometer, a stirrer and a nitrogen blowing tube, purged with nitrogen, and then reacted at 50 ° C. for 10 hours with stirring. After completion of the reaction, the solvent was removed by heating to 55 ° C. under reduced pressure. After removal of the solvent, filtration and drying were performed to produce a thermoplastic polyurethane resin fine powder (G-9).
The average particle size of (G-9) was 76 μm, Cv = 110, SP value of thermoplastic polyurethane resin (A-9) 10.7, and thermal softening temperature 145 ° C.

Production of thermoplastic polyurethane resin powder (D-9) 150 parts of (G-9) prepared above were mixed with THF (boiling point 66 ° C., polyurethane resin (A-2)) as solvent (B-1). After spraying 23 parts of the difference 2.4) under stirring and homogenizing, the temperature was raised to 70 ° C. with stirring at a peripheral speed of 1.5 m / s using a planetary mixer manufactured by Asada Steel Corporation. Thereafter, it was immediately cooled to 40 ° C. When the center particle diameter was measured, the center particle diameter was 190 μm, so the temperature was raised to 60 ° C., and the solvent was distilled off under reduced pressure to obtain a thermoplastic polyurethane resin powder (D-9). The obtained (D-9) had an average particle size of 190 μm and Cv = 38.

Example 10
Production of thermoplastic polyurethane resin powder (D-10) 150 parts of thermoplastic polyurethane resin fine powder (G-9) prepared in Example 7 and ethyl acetate (boiling point 77 ° C., polyurethane resin) as solvent (B-1) (A-2) SP value difference 1.6) was sprayed with 20 parts under stirring and homogenized, and then stirred with a planetary mixer manufactured by Asada Steel Co., Ltd. at a peripheral speed of 1.5 m / s. Then, the temperature was raised to 70 ° C. and immediately cooled to 40 ° C. When the center particle diameter was measured, the center particle diameter was 170 μm. Therefore, the temperature was raised to 60 ° C., the solvent was distilled off under reduced pressure, and a thermoplastic polyurethane resin powder (D-10) was obtained. The obtained (D-10) had an average particle size of 170 μm and Cv = 35.

Reference Comparative Example 1
A four-necked flask equipped with a stirrer, a cooling tube, a nitrogen introduction tube, and a thermometer was charged with 60 parts of acetone and 60 parts of isophoronediamine (hereinafter, IPDA), and reacted at 40 ° C. for 12 hours under nitrogen. The reaction rate at this time was 65%. Furthermore, 14.0 parts of di-n-butylamine was added and mixed to obtain a chain extender solution (K-2).
As a dispersant, 15 parts of polyvinyl alcohol [PVA-235 manufactured by Kuraray Co., Ltd.] was dissolved in 985 parts of water and the temperature was adjusted to 25 ° C. to obtain a dispersion medium (Y-2).
Into a four-necked flask equipped with a stirrer and a thermometer, 2,000 parts of polycaprolactone diol having a number average molecular weight of 2,000 ["Placcel L220AL", manufactured by Daicel Corporation] was charged, and 110 parts under a reduced pressure of 3 mmHg. Dehydration was performed for 1 hour by heating to ° C. Subsequently, 457 parts of isophorone diisocyanate (hereinafter referred to as IPDI) was added and reacted at 110 ° C. for 10 hours to obtain an isocyanate group-terminated urethane prepolymer having an isocyanate content of 3.6%. This is designated as resin precursor (A-1-1).
50 parts of the resin precursor (A-1-1) and 12.5 parts of ethyl acetate were mixed and temperature-controlled at 55 ° C. to prepare a dispersed phase (X-1).
180 parts of (Y-2) was put into a beaker. Next, after (B1-1) was mixed into 62.5 parts of (X-1), it was immediately put into a beaker, and then mixed for 1 minute at a rotation speed of 9000 rpm using an ultradisperser (manufactured by Yamato Scientific Co., Ltd.). To obtain a dispersion. The obtained dispersion was treated in the same manner as in Example 1 to obtain a thermoplastic polyurethane resin powder (D-8). The obtained (D-8) had an average particle size of 181 μm and Cv = 210.

Reference Comparative Example 2
50 parts of the resin precursor (A-1-1) prepared in the same manner as in Comparative Example 1, 12.5 parts of ethyl acetate and 5 parts of talc were mixed and temperature-controlled at 55 ° C., and the dispersed phase (X-2) was changed. Prepared.
In a tank equipped with a stirrer, 67.5 parts of (X-2) and 6.6 parts of (B1-1) prepared as in Comparative Example 1 were mixed. Using a gear pump, the mixed liquid and the dispersion medium (Y-2) prepared in the same manner as in Comparative Example 1 are quantitatively mixed at a liquid ratio of 203.5: 300 and a static mixer having a diameter of 1 cm and 15 elements (Noritake Company) Manufactured). The liquid feeding speed at this time was adjusted so that the mixing time in the static mixer was 0.3 seconds. The mixed dispersion mixed with the static mixer was treated in the same manner as in Example 1 to obtain a thermoplastic polyurethane resin powder (D-9). The obtained (D-9) had an average particle size of 145 μm and Cv = 246.

Reference Comparative Example 3
150 parts of (G-2) prepared in Reference Example 2 were heated to 140 ° C. and continued for 3 hours with stirring at a peripheral speed of 0.05 m / s using a planetary mixer manufactured by Asada Steel Corporation. Then, the solvent was distilled off under reduced pressure, and filtration, washing and drying were performed to obtain a thermoplastic polyurethane resin powder (D-10). The obtained (D-10) had an average particle size of 765 μm and Cv = 145.

Comparative Example 4
150 parts of (G-8) prepared in Example 6 were mixed with THF (boiling point 66 ° C., SP value difference with polyurethane resin (A-6) 2.4) as solvent (B-1) under stirring. After spraying 28 parts and homogenizing, the mixture was heated to 45 ° C. for 3 hours under stirring at a peripheral speed of 12.0 m / s with a high-speed mixer manufactured by Fukae Kogyo Co., Ltd. Was distilled off to obtain a thermoplastic polyurethane resin powder (D-11). The obtained (D-11) was not granulated, and there was no change in the average particle diameter and Cv.

Comparative Example 5
120 parts of (G-8) prepared in Example 6 were mixed with methanol (boiling point 66 ° C., SP value difference 3.1 with polyurethane resin (A-6)) as solvent (B-1) under stirring. After spraying 30 parts and stirring with a planetary mixer manufactured by Asada Steel Corporation at a peripheral speed of 0.5 m / s, the temperature was raised to 80 ° C. and continued for 3 hours, and then the solvent was distilled off under reduced pressure. A thermoplastic polyurethane resin powder (D-12) was obtained. The obtained (D-12) was not granulated, and there was no change in the average particle diameter and Cv.

The results of Examples 1 to 10 and Comparative Examples 1 to 5 are summarized in Table 1 below.
Further, Table 2 shows the center particle diameter and particle diameter distribution Cv of the thermoplastic polyurethane resin fine powder (G) and the thermoplastic polyurethane resin powder (D).

The central particle size and particle size distribution were measured with a laser diffraction particle size distribution measuring device [Microtrac MT3000II Nikkiso Co., Ltd.].

Using a flow tester CFT-500 [manufactured by Shimadzu Corporation], the temperature was raised at a constant speed under the following conditions, and the temperature at which the resin started to soften was defined as the heat softening temperature.
Load: 5kg
Die: 0.5mmΦ-1mm
Temperature increase rate: 5 ° C / min

The thermoplastic polyurethane resin powders of Examples 1 to 10 have a small particle size distribution Cv and a sharp particle size distribution as compared with Comparative Examples 1 to 3. Moreover, it is a center particle diameter suitable for a slush molding use compared with the comparative examples 4 and 5. For these reasons, there is no fine particle or coarse particle, and it is excellent as a method for producing a thermoplastic polyurethane resin powder mainly suitable for slush molding.

Molded articles formed from the thermoplastic polyurethane resin powder composition containing the thermoplastic polyurethane resin powder obtained by the production method of the present invention, for example, the skin is used as an automobile interior material, for example, an instrument panel, a door trim, etc. Preferably used.

Claims (9)

A thermoplastic polyurethane resin powder (D) having a particle size distribution Cv of 20 to 55, comprising the following step 1 and step 2-2 The manufacturing method of the thermoplastic polyurethane resin powder (D) containing this.
Process 1
The process of manufacturing the thermoplastic polyurethane resin fine powder (G) whose center particle diameter containing a thermoplastic polyurethane resin (A) is 1-100 micrometers.

Step 2-2
An organic solvent (B) having a solubility parameter (SP value) difference of 3.0 or less from the thermoplastic polyurethane resin (A) in the presence of 5 to 30% by weight based on the weight of (G) While stirring at a speed of 0.5 to 50 m / s, (B) is added dropwise and / or sprayed to (G), and the thermoplastic polyurethane resin fine powder (G) is heat-softened to 70 to [(A). A step of granulating by heating to a temperature +10] ° C. and granulating into a thermoplastic polyurethane resin powder (D) by cooling after confirming that the center particle size has reached a certain particle size. The manufacturing method of Claim 1 which sprays and adds an organic solvent (B) to a thermoplastic polyurethane resin fine powder (G) in process 2-2. The manufacturing method according to claim 1 or 2, wherein the thermoplastic polyurethane resin (A) has a heat softening temperature of 100 to 200 ° C. The organic solvent (B) is at least one selected from the group consisting of ketones having 3 to 9 carbon atoms, ethers having 4 to 8 carbon atoms, and esters having 3 to 6 carbon atoms. The manufacturing method of any one of Claims. The production method according to any one of claims 1 to 4, wherein the organic solvent (B) is at least one selected from the group consisting of acetone, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, and ethyl acetate. Granulation is performed in the presence of fine particle powder (P) having a center particle diameter of 0.1 to 10 μm and not softened at the granulation temperature, and based on the weight of thermoplastic polyurethane resin fine powder (G) (P) Is carried out in the presence of 0.05 to 5% by weight. The production method according to claim 6, wherein the fine particle powder (P) is one of methyl methacrylate / ethylene glycol dimethacrylate copolymer particles and silica particles. The manufacturing method according to claim 1, wherein the thermoplastic polyurethane resin powder (D) has a center particle diameter of 10 to 500 μm. The additive is added in the middle of obtaining the thermoplastic polyurethane resin powder (D) by the production method according to any one of claims 1 to 8, or the additive is added to the obtained (D). A process for producing a thermoplastic polyurethane resin powder composition characterized by the above.