JP4697383B2 - Thermoplastic polyurethane resin composition for powder molding and method for producing the same - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a resin composition for powder molding, and more specifically, a thermoplastic polyurethane resin for powder molding that gives a molded product excellent in powder flowability, meltability, mold release property, and adhesiveness with foamed polyurethane. The present invention relates to a composition and a method for producing the composition.

  In recent years, the powder molding method has been used for automobile interior materials because of its advantages such as easy shaping of products with complex shapes (undercut, deep drawing, etc.), uniform thickness, and good material yield. In general, soft polyvinyl chloride resin (hereinafter referred to as PVC) powder has been used for such applications. For example, as a skin material for interior parts such as an instrument panel, a console box, a door trim, and a glove box of an automobile, a powder molded product of a soft polyvinyl chloride resin has been conventionally used.

However, the soft vinyl chloride resin molded article loses the soft feeling because the plasticizer contained in the material is transferred to the surface due to the influence of heat, light, etc. due to long-term use. Further, it has been pointed out that when this molded product is incinerated, the incinerator is corroded by hydrogen chloride gas generated at that time. In order to solve these problems, development of a powder molding material mainly composed of a thermoplastic polyurethane resin as a substitute for the vinyl chloride material has been advanced.
However, this thermoplastic polyurethane resin for powder molding has problems in powder flowability and meltability (smoothness of the skin obtained by molding) necessary to ensure a uniform thickness. . Therefore, regarding powder flowability and meltability, a method of imparting powder fluidity by adding a resin powder having an average particle diameter of 10 μm or less that does not soften at 160 ° C. or less (see Patent Document 1), a coupling agent A method of improving the meltability by mixing fine powdered silica having an average particle diameter of 10 μm or less that has been surface-treated (see Patent Document 2) has been proposed. However, in the method described in Patent Document 1, although the fluidity of the powder is improved, the adhesion to the polyurethane foam (the adhesion between the skin formed by molding the thermoplastic polyurethane resin composition for powder molding and the polyurethane foam) ) Is bad, and the method described in Patent Document 2 has a problem that the molding temperature at the time of slush molding has to be increased, and these solutions are required.

JP 2000-017033 A JP 2001-011301 A

  The present invention has been made in view of the above circumstances, and the object of the present invention is excellent in powder flowability, meltability, and adhesiveness with foamed polyurethane, and also in mold release after powder molding. It is an object to provide an excellent thermoplastic polyurethane resin composition for powder molding and a method for producing the same.

  As a result of intensive studies to achieve the above-mentioned object, the present inventors have found that a powdered thermoplastic polyurethane, a powder colorant containing a powder pigment and a pigment dispersant, a plasticizer, and an average particle size of 0.1 to 10 μm. The thermoplastic polyurethane resin composition for powder molding containing the hydroxyl group-containing aromatic vinyl copolymer is further excellent in powder flowability, meltability, adhesiveness with foamed polyurethane, and demoldability. Based on this finding, the present invention has been completed.

Thus, according to the present invention, the powdered thermoplastic polyurethane (A), the powder colorant (B) containing the powder pigment (b1) and the pigment dispersant (b2), the plasticizer (C), and the average particle size are A polyurethane resin composition for powder molding comprising a hydroxyl group-containing aromatic vinyl copolymer (D) having a size of 0.1 to 10 μm is provided. The polyurethane resin composition for powder molding preferably further contains a hydroxyl group-modified and / or (meth) acryloxy group-modified silicone oil (E).
According to the present invention, the powdered thermoplastic polyurethane (A) and the powder colorant (B) containing the powder pigment (b1) and the pigment dispersant (b2) are mixed, and then the resulting mixture is The plasticizer (C) is added and mixed, and then the hydroxyl group-containing aromatic vinyl copolymer (D) having an average particle size of 0.1 to 10 μm is added to and mixed with the resulting mixture. A method for producing a thermoplastic polyurethane resin composition for powder molding is provided.

  According to the present invention, powder molding of skin materials of automobile interior parts such as instrument panels, headrests, console boxes, door trims, armrests, etc. is easy, and powder flowability at the time of molding, meltability, adhesion to foamed polyurethane There is provided a thermoplastic polyurethane resin composition for powder molding which gives a powder molded article having excellent properties and demoldability.

  The thermoplastic polyurethane resin composition for powder molding of the present invention comprises a powdery thermoplastic polyurethane (A), a powder colorant (B) containing a powder pigment (b1) and a pigment dispersant (b2), a plasticizer ( C) and a hydroxyl group-containing aromatic vinyl copolymer (D) having an average particle diameter of 0.1 to 10 μm.

  As the powdery thermoplastic polyurethane (A), those produced from the organic polyisocyanate (A1), the polymer polyol (A2) and, if necessary, the chain extender (A3) and / or the terminator (A4) can be used. .

  The organic polyisocyanate (A1) is an aliphatic polyisocyanate having 2 to 12 carbon atoms (excluding carbon in the NCO group; the same applies hereinafter) [ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 2,2,4-trimethylhexane-1,6-diisocyanate, lysine diisocyanate, 2,6-diisocyanatoethylcaproate, etc.]; alicyclic polyisocyanate having 4 to 15 carbon atoms [isophorone diisocyanate (IPDI), 4 , 4'-dicyclohexylmethane diisocyanate (hydrogenated MDI), cyclohexylene diisocyanate, methylcyclohexylene diisocyanate, etc.]; araliphatic polyisocyanate having 8 to 15 carbon atoms [m- and p-xylyl Diisocyanate (XDI), α, α, α ′, α′-tetramethylxylylene diisocyanate (TMXDI), etc.]; C6-C15 aromatic polyisocyanate [2,4- or 2,6-tolylene diisocyanate (TDI), diethylbenzene diisocyanate, 2,4′- or 4,4′-diphenylmethane diisocyanate (MDI), naphthylene diisocyanate, etc.]; Modified products containing biuret groups, isocyanurate groups, etc.). Two or more of these can be used in combination.

  Of the organic polyisocyanates (A1), preferred are aliphatic polyisocyanates and alicyclic polyisocyanates from the viewpoint of light resistance of the molded article, and particularly preferred are HDI, IPDI, and hydrogenated MDI.

  Examples of the polymer polyol (A2) include polyester polyol (A21), polyether polyol (A22), and a mixture of two or more thereof. The hydroxyl group equivalent of the polymer polyol (A2) (number average molecular weight per hydroxyl group based on hydroxyl group value measurement, hereinafter the same) is usually 250 to 5,000, from the viewpoint of obtaining a soft feeling and desired strength of the molded product. Preferably it is 350-2,500, More preferably, it is 400-1,500. The number of functional groups is usually 2 to 4, preferably 2 to 3, particularly preferably 2.

  The polyester polyol (A21) includes (1) a condensation polymerization of a low molecular polyol and / or a polyether polyol and a dicarboxylic acid compound; (2) a lactone monomer opened in the low molecular polyol and / or the polyether polyol. Additions and their dicarboxylic acid-modified products; (3) those obtained by condensation polymerization of low molecular polyols and / or polyether polyols and carbonic acid diesters (dimethyl carbonate, ethylene carbonate, etc.). Two or more of these can be used in combination.

The low molecular weight polyol includes a bivalent or trivalent or higher polyol having a hydroxyl group equivalent of less than 250. Specific examples thereof include dihydric alcohols {for example, aliphatic diols having 2 to 12 carbon atoms [linear diols (ethylene glycol, diethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentane Diols, 1,6-hexanediol, and the like, and branched diols (1,2-propylene glycol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2,2-diethyl-1,3- Propanediol, 1,2-, 1,3- and 2,3-butanediol, 1,2-decanediol, etc.)]; and diols having a cyclic group having 6 to 25 carbon atoms, for example, Japanese Patent Publication No. 45-1474 No .: alicyclic group-containing diol [1,4-bis (hydroxymethyl) cyclohexane, hydrogenated bisphenol A, etc.] Aromatic ring-containing diol [m- and p-xylylene glycol, dihydric phenol [monocyclic dihydric phenol (hydroquinone, resorcin, etc.), bisphenol (bisphenol A, bisphenol S, bisphenol F, etc.), alkylene of dihydroxynaphthalene, etc. Oxide adducts (hydroxyl equivalents less than 250), bishydroxyalkyl (2 to 4 carbon atoms) esters of aromatic dicarboxylic acids [such as bis (2-hydroxyethyl) terephthalate]]; trivalent alcohols such as glycerin, trimethylolpropane , And these alkylene oxide adducts (with a hydroxyl equivalent of less than 250). Two or more of these can be used in combination.
As the polyether polyol, those listed in (A22) described later can be used. Those having a hydroxyl equivalent weight of 500 or less are preferred. Among these, preferred are aliphatic diols and aromatic ring-containing diols.

  In the above and the following, the alkylene oxide includes an alkylene oxide having 2 to 10 or more carbon atoms and phenyl or halo substitution thereof, ethylene oxide (hereinafter abbreviated as EO), propylene oxide (hereinafter abbreviated as PO), 1,2-butylene oxide, 1,3-butylene oxide, 1,4-butylene oxide and 2,3-butylene oxide, styrene oxide, α-olefin oxide having 5 to 10 or more carbon atoms, epihalohydrin (epichlorohydrin) Phosphorus etc.). Two or more of these can be used in combination by block and / or random addition. Preference is given to EO, PO and combinations with these blocks and / or random additions.

  Specific examples of the dicarboxylic acid compound (1) include aliphatic dicarboxylic acids having 4 to 15 carbon atoms such as succinic acid, adipic acid, sebacic acid, glutaric acid, azelaic acid, maleic acid and fumaric acid; terephthalic acid Aromatic dicarboxylic acids having 8 to 15 carbon atoms, such as isophthalic acid and naphthalenedicarboxylic acid; ester-forming derivatives thereof, that is, anhydrides, lower alkyl (1 to 4 carbon atoms) esters, acid halides (acid chlorides, etc.) ) And the like. Two or more of these can be used in combination.

  Examples of the lactone monomer (2) include lactones having 4 to 12 carbon atoms such as γ-butyrolactone, ε-caprolactone, and γ-valerolactone. Two or more of these can be used in combination.

  Specific examples of the polyester polyol (A21) include polyethylene adipate diol, polybutylene adipate diol, polyhexamethylene adipate diol, polybutylene isophthalate diol, polyhexamethylene isophthalate diol, polyneopentylene adipate diol, polyethylene propylene adipate diol. , Polyethylene butylene adipate diol, polybutylene hexamethylene adipate diol, poly (polytetramethylene ether) adipate diol, poly (diethylene glycol) isophthalate diol, polycaprolactone diol, adipic acid modified polycaprolactone diol, terephthalic acid modified polycaprolactone diol, isophthal Acid-modified polycaprolactone diol, polyhe Sa methylene carbonate diol, and the like. Two or more of these can be used in combination.

  Examples of the polyether polyol (A22) include compounds having a structure in which an alkylene oxide is added to a low-molecular polyol (for example, those exemplified as the raw material of the polyester polyol (A21) described above).

  Specific examples of the polyether polyol (A22) include polyethylene glycol, polypropylene glycol, polyoxyethylene-polyoxypropylene (block and / or random) glycol, polytetramethylene ether glycol, polyoxybutylene-polyoxyethylene (block and And / or random) glycols, polyoxybutylene-polyoxypropylene (block and / or random) glycols, EO and / or PO adducts of bisphenol A. Two or more of these can be used in combination.

  Among the polymer polyols (A2), preferred are polyester polyols (A21), and particularly preferred are condensates of aliphatic diols and dicarboxylic acid compounds, particularly condensed polyester diols of aromatic dicarboxylic acids.

  Examples of the chain extender (A3) used as necessary include a low molecular polyol (A31) and a polyamine (A32). The chain extender (A3) has 2 to 3 functional groups, particularly 2 and a hydroxyl group (amino group) equivalent of less than 250, particularly 200 or less. The low molecular polyol (A31) is a low molecular polyol exemplified as a raw material of the polyester polyol (A21) and a glycol ester of monohydroxymonocarboxylic acid (hydroxyacetic acid, lactic acid, etc.) (for example, described in JP-A-61-190717). For example). As polyamine (A32), (1) C2-C12 aliphatic polyamine (ethylenediamine, propylenediamine, tetramethylenediamine, hexamethylenediamine, N-hydroxyethylethylenediamine, diethylenetriamine, etc.); (2) C6-C6 15 alicyclic polyamines (4,4′-diaminocyclohexylmethane, 1,4-diaminocyclohexane, 1,3-diaminomethylcyclohexane, isophoronediamine, etc.); (3) araliphatic polyamines having 8 to 15 carbon atoms ( m- and p-xylylenediamine, etc.); aromatic polyamines (4,4′-diaminodiphenylmethane, tolylenediamine, diethyltolylenediamine, phenylenediamine, etc.); and their ketimines (some or all of the amino groups are Ketone (3 carbon atoms 10, such as acetone, methyl ethyl ketone, block (ketiminated) are ones] in methyl isobutyl ketone); and mixtures of two or more thereof. Among the polyamines (A32), aliphatic polyamines, alicyclic polyamines, and ketimines thereof are preferable from the viewpoint of light resistance of the molded product. The amount of the chain extender (A3) in the powdered thermoplastic polyurethane (A) is usually 0 to 30%, preferably 0.5 to 20% based on the weight of the polymer polyol (A2).

  Examples of the terminator (A4) include monohydric alcohol (A41) and monoamine (A42). Specific examples of the monohydric alcohol (A41) include aliphatic monohydric alcohols having 1 to 20 carbon atoms (methanol, ethanol, propanol, butanol, octanol, ethyl cellosolve, ethyl carbitol, etc.) and fats having 6 to 10 carbon atoms. Cyclic monohydric alcohols (cyclohexanol, etc.), C7-20 aromatic ring-containing monohydric alcohols (benzyl alcohol, hydroxyethylbenzene, monohydric phenols (phenol, cresol, etc.) (poly) oxyalkylenes (of alkylene groups) And a mixture of two or more thereof. Specific examples of the monoamine (A42) include mono- or di-alkylamines having 1 to 10 carbon atoms in the alkyl group (such as methylamine, ethylamine, diethylamine, n-butylamine, di-n-butylamine), and 6 to 6 carbon atoms. 10 alicyclic monoamines (such as cyclohexylamine), C6-C15 aromatic ring-containing monoamines (such as benzylamine and aniline), C4-C10 heterocyclic monoamines (such as morpholine), carbons of hydroxyalkyl groups Examples thereof include mono- and di-alkanolamines of 2 to 4 (monoethanolamine, diethanolamine, diisopropanolamine, etc.) and mixtures of two or more thereof.

  The number average molecular weight of the powdered thermoplastic polyurethane (A) is usually 5,000 to 100,000, preferably 10,000 to 50,000. The terminal of the powdery thermoplastic polyurethane (A) may be terminated with an active hydrogen-containing group (hydroxyl group, amino group, etc.) or a terminator (A4).

  The primary average particle diameter of the powdered thermoplastic polyurethane (A) is usually 50 μm to 500 μm, preferably 100 μm to 300 μm, more preferably 120 μm to 200 μm. If the particle diameter is larger than 500 μm, pinholes are likely to occur in the powder-molded skin. On the other hand, when the particle size is smaller than 50 μm, the powder fluidity is deteriorated, the thickness of the skin becomes uneven, and the powder tends to aggregate during storage, which is not preferable.

  The powdery thermoplastic polyurethane (A) is obtained by reacting the organic polyisocyanate (A1), the polymer polyol (A2) and, if necessary, the chain extender (A3) by water or non-aqueous emulsion polymerization. And having a spherical shape can be obtained. Alternatively, a product having a large particle size obtained by suspension polymerization is pulverized using a known pulverizer such as a turbo mill, a hammer mill, a pulverizer, etc. to obtain a particle having an intended particle size and an irregular shape. Can do. In the present invention, both the former and the latter can be used.

  The powder colorant (B) contains a powder pigment (b1) and a pigment dispersant (b2).

  The powder pigment (b1) alone has problems such as insufficient dispersion, high scattering properties, and poor workability when mixed with thermoplastic polyurethane particles. Therefore, it is mixed and dispersed in a resin such as low molecular weight polyethylene or petroleum resin, and then pulverized into fine particles, mixed and dispersed with an inorganic dispersant such as silica or calcium carbonate, or the surface of the powder pigment (b1) is treated with silane. A so-called powder colorant (B) that is surface-treated with a coupling agent or the like is usually used. A substance having a series of pigment dispersion effects, such as the above-mentioned resins such as low molecular weight polyethylene and petroleum resin; inorganic dispersants such as silica and calcium carbonate; silane coupling agents; is referred to as pigment dispersant (b2). In the preparation of the powder colorant (B), the ratio of the powder pigment (b1) to the pigment dispersant (b2) is usually 20 to 80% by weight of the powder pigment (b1) and 80 to 20% by weight of the pigment dispersant (b2). %.

  It does not specifically limit as a powder pigment (b1), A well-known organic pigment and / or an inorganic pigment can be used. Examples of organic pigments include insoluble azo pigments, copper phthalocyanine pigments, quinacudrine pigments, and inorganic pigments include chromates, ferrocyan compounds, metal oxides (titanium oxide, zinc oxide, etc.), metal salts ( Sulfate, silicate, carbonate, phosphate, etc.), metal powder, carbon black and the like. These can be used alone or in combination of two or more.

  Examples of the pigment dispersant (b2) include resins such as low molecular weight polyethylene and petroleum resin; inorganic dispersants such as silica and calcium carbonate; silane coupling agents; These can be used alone or in combination of two or more.

The powder colorant (B) can be used alone or in combination of two or more.
The amount ratio of the powder colorant (B) to the powdered thermoplastic polyurethane (A) is based on the content of the powder pigment (b1) in the powder colorant (B) with respect to 100 parts by weight of the powdered thermoplastic polyurethane (A). In general, it is 0.1 to 20 parts by weight, preferably 0.5 to 10 parts by weight, particularly preferably 1 to 5 parts by weight.

  As the plasticizer (C), JP-A-2000-103957, US application Ser. No. 09 / 406,129, for example, polyalkylene glycol (alkylene group having 2 to 4 carbon atoms, polymerization degree 2 to 25) aromatic monocarboxylic acid (carbon number 7 to 20: benzoic acid, etc.) diester; phthalate Acid esters (dibutyl phthalate, dioctyl phthalate, butyl benzyl phthalate, diisodecyl phthalate, etc.); aliphatic dibasic acid esters (di-2-ethylhexyl adipate, di-2-ethylhexyl sebacate, etc.); trimellitic acid Esters [tri-2-ethylhexyl trimellitic acid, tridecyl trimellitic acid, etc.]; Fatty acid esters [butyl oleate, isobutyl myristate, etc.]; Aliphatic phosphate esters [trimethyl phosphate, triethyl phosphate, tributyl phosphate, tri-2 -Ethylhexyl phosphate Tributoxybutyl phosphate, etc.]; aromatic phosphate esters (triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl phosphate, xylenyl diphenyl phosphate, 2-ethylhexyl diphenyl phosphate, tris (2,6 -Dimethylphenyl) phosphate and the like]; halogen-containing aliphatic phosphate ester [tris (chloroethyl) phosphate, tris (β-chloropropyl) phosphate, tris (dichloropropyl) phosphate, tris (tribromoneopentyl) phosphate, etc.]; A mixture of two or more of these may be mentioned. Of these, preferred are phthalate esters (dibutyl phthalate, dioctyl phthalate, dibutylbenzyl phthalate, diisodecyl phthalate, etc.) and aliphatic dibasic acid esters (di-2-ethylhexyl adipate, di-2 sebacate). -Ethylhexyl etc.] and particularly preferred are aliphatic dibasic acid esters [di-2-ethylhexyl adipate, di-2-ethylhexyl sebacate etc.].

  The hydroxyl group-containing aromatic vinyl copolymer (D) has an average particle size of 0.1 to 10 μm and is a kind of so-called dusting agent. A dusting agent is an agent that suppresses aggregation of powders and improves powder flowability.

  When the average particle size of the hydroxyl group-containing aromatic vinyl copolymer is less than 0.1 μm, the handleability is remarkably deteriorated, and the fluidity improving effect and the blocking preventing effect of the thermoplastic polyurethane resin composition for powder molding are deteriorated. On the other hand, when it exceeds 10 μm, the adhesiveness with the foamed polyurethane (adhesiveness between the skin formed by molding the thermoplastic polyurethane resin composition for powder molding and the foamed polyurethane) is deteriorated. The average particle diameter is preferably 0.5 to 8 μm.

  The hydroxyl group-containing aromatic vinyl copolymer (D) introduces a hydroxyl group into a part of a previously produced aromatic vinyl copolymer or copolymerizes a monomer containing a hydroxyl group with an aromatic vinyl monomer. Can be obtained. Preferably, an aromatic vinyl monomer, a hydroxyl group-containing vinyl monomer described later, and any other copolymerizable monomer are copolymerized. Particularly preferably, it is obtained by emulsion polymerization of the monomer and pulverizing the agglomerated polymer obtained to make fine particles, or by fine suspension polymerization of the monomer. desirable.

The method for introducing a hydroxyl group into an aromatic vinyl copolymer produced in advance is not particularly limited. A method for copolymerizing a monomer containing a hydroxyl group with an aromatic vinyl monomer is as described below.
First, as the aromatic vinyl monomer, for example, styrene, α-methylstyrene, β-methylstyrene, p-methylstyrene, 4-t-butylstyrene, 3-chlorostyrene, 4-chlorostyrene, 3,4 -Dichlorostyrene, 3-methoxystyrene, 4-methoxystyrene, 2-vinyltoluene, 3-vinyltoluene, 4-vinyltoluene, 4-vinyl-1,2-xylene, 3-ethylstyrene, 4-ethylstyrene, 1 -Vinyl naphthalene, 2-vinyl naphthalene, 5-vinyl anthracene, etc. are mentioned. These can be used alone or in combination of two or more.

  Examples of the hydroxyl group-containing vinyl monomer include hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and (meth) acrylic acid-2,3. Hydroxyl group-containing (meth) acrylic acid esters such as dihydroxypropyl, (meth) acrylic acid-2-hydroxyamyl, (meth) acrylic acid-2-hydroxyoctyl, (meth) acrylic acid-2-hydroxydodecyl; Hydroxyl-containing vinyl ethers such as hydroxypropyl vinyl ether, 2-hydroxybutyl vinyl ether, and 2,4-dihydroxyoctyl ether; hydroxyl-containing vinyl monocarboxylic acid esters such as vinyl hydroxyacetate and vinyl 3-hydroxypropionate; maleic acid-2- Hydroxypropyl Such as fumarate (2-hydroxyethyl), a hydroxyl group-containing vinyl dicarboxylic acid esters; vinyl alcohol; that is contained hydroxyl groups on the aromatic vinyl monomer; and the like. These can be used alone or in combination of two or more.

  In the copolymerization of the aromatic vinyl monomer and the hydroxyl group-containing vinyl compound, any other copolymerizable monomer can be copolymerized to such an extent that the effects of the present invention are not impaired. For example, the following monomers are mentioned. (Meth) acrylic acid esters such as ethyl acrylate and methyl methacrylate; vinyl cyanide compounds such as (meth) acrylonitrile and vinylidene cyanide; vinyl monocarboxylic acid esters such as vinyl acetate and vinyl propionate; monobutyl maleate and the like Examples thereof include vinyl dicarboxylic acid esters; vinyl ether compounds such as ethyl vinyl ether and methyl vinyl ether; functional group-containing (meth) acrylic acid esters such as butoxyethyl (meth) acrylate and glycidyl (meth) acrylate. These can be used alone or in combination of two or more.

  The content of the hydroxyl group-containing vinyl compound unit in the hydroxyl group-containing aromatic vinyl copolymer (D) is usually 10 to 60% by weight, preferably 20 to 50% by weight. If it is less than 10% by weight, the adhesiveness to the polyurethane foam is deteriorated, and if it exceeds 60% by weight, the heat resistance of the molded product is deteriorated.

  The hydroxyl group-containing aromatic vinyl copolymer (D) includes those having various monomer compositions, those having various hydroxyl group contents, those having various average particle diameters within a range of 0.1 to 10 μm, and the like. These can be used alone or in combination of two or more.

  The content of the hydroxyl group-containing aromatic vinyl copolymer (D) with respect to 100 parts by weight of the powdered thermoplastic polyurethane (A) is usually 0.1 to 30 parts by weight, preferably 1 to 20 parts by weight. If it is less than 0.1 part by weight, the powder fluidity may be lowered, and if it exceeds 30 parts by weight, it may be difficult to remove from the mold during powder molding.

  Various additives can be added or used in combination with the thermoplastic polyurethane resin composition for powder molding of the present invention as desired. For example, known various dusting agents, various blocking inhibitors, various stabilizers (for example, various antioxidants, various ultraviolet absorbers), various antistatic agents, various flame retardants, etc. Can be added.

  Furthermore, a known polymer other than the polymer component constituting the thermoplastic polyurethane resin composition for powder molding of the present invention can be blended and used without departing from the spirit of the present invention.

  The thermoplastic polyurethane resin composition for powder molding of the present invention preferably further comprises a hydroxyl group-modified and / or (meth) acryloxy group-modified silicone oil (E).

  The hydroxyl group-modified and / or (meth) acryloxy group-modified silicone oil (E) improves the releasability, but the hydroxyl group-modified silicone oil and / or (meth) acryloxy group-modified silicone oil (E) [" The term “(meth) acryloxy group” means a methacryloxy group and / or an acryloxy group] in a predetermined amount of the thermoplastic polyurethane resin composition for powder molding, which has been a problem with conventionally used silicone oils. In addition, the adhesion between the skin formed by molding the thermoplastic polyurethane resin composition for powder molding and foamed polyurethane is also improved.

The hydroxyl group-modified silicone oil in the hydroxyl group-modified and / or (meth) acryloxy group-modified silicone oil (E) refers to a hydroxyl group, that is, an —OH group bonded to the silicone oil. Specifically, “—R— (OH) x”, “—Z—R— (OH) x” or “—Z—O—R— (OH) x” (where R is an aromatic ring or alkyl Group, Z is an alkyl group, x is an integer of 1 to 3), or a silyl group or siloxane group having the hydroxyl group-containing group is at least a silicon atom and an oxygen atom of the siloxane skeleton of the silicone oil. Combined into one.
The hydroxyl group-containing group is not particularly limited, for _{example, -C 6 H 4 OH, -C} 10 H 6 OH, -C 2 H 4 OH, -C 3 H 6 OH, -C 3 H 6 -C 6 H _{4 OH, -C 2 H 4 O} -C 6 H 4 OH, -C 2 H 4 O-C 6 H 4 OH, -C 3 H 6 O-C 6 H 4 OH, -C 3 H 6 O-C Examples include ₂ H ₄ OH, —C ₃ H ₆ O—C ₆ H ₁₁ (OH) _2, and the like containing a hydroxyl group bonded to an aromatic ring or an alkyl group. These can have 1 type, or 2 or more types.

The (meth) acryloxy group-modified silicone oil in the hydroxyl group-modified and / or (meth) acryloxy group-modified silicone oil (E) is a (meth) acryloxy group, that is, —O—CO—CH═CH ₂ group and / or _{-O-CO-C (CH 3} ) = CH 2 group refers to that which it is joined to the silicone oil. Specifically, “—R— (O—CO—CH═CH ₂ ) x and / or —R— (O—CO—C (CH ₃ ) ═CH ₂ ) x”, “—Z—R— ( O—CO—CH═CH ₂ ) x and / or —ZR— (O—CO—C (CH ₃ ) ═CH ₂ ) x ”or“ —Z—O—R— (O—CO—CH═ CH ₂ ) x and / or —Z—O—R— (O—CO—C (CH ₃ ) ═CH ₂ ) x ”(where R is an aromatic ring or an alkyl group, Z is an alkyl group, x is 1 At least one of the silicon atom and the oxygen atom of the siloxane skeleton of the silicone oil is a (meth) acryloxy group-containing group represented by (integer of ~ 3), or a silyl group or siloxane group having the (meth) acryloxy group-containing group. It is combined with.

The (meth) acryloxy group-containing group is not particularly limited, for _{example, -C 6 H 4 O-CO} -CH = CH 2, -C 6 H 4 O-CO-C (CH 3) = CH 2, - _{C 10 H 6 O-CO-} CH = CH 2, -C 10 H 6 O-CO-C (CH 3) = CH 2, -C 2 H 4 O-CO-CH = CH 2, -C 2 H 4 _{O-CO-C (CH 3} ) = CH 2, -C 3 H 6 O-CO-CH = CH 2, -C 3 H 6 O-CO-C (CH 3) = CH 2, -C 3 H 6 _{-C 6 H 4 O-CO-} CH = CH 2, -C 3 H 6 -C 6 H 4 O-CO-C (CH 3) = CH 2, -C 2 H 4 O-C 6 H 4 O- _{CO-CH = CH 2, -C} 2 H 4 O-C 6 H 4 O-CO-C (CH 3) = CH 2, -C 2 H 4 O-C 6 H 4 O-CO _{CH = CH 2, -C 2 H} 4 O-C 6 H 4 O-CO-C (CH 3) = CH 2, -C 3 H 6 O-C 6 H 4 O-CO-CH = CH 2, - _{C 3 H 6 O-C 6} H 4 O-CO-C (CH 3) = CH 2, -C 3 H 6 O-C 2 H 4 O-CO-CH = CH 2, -C 3 H 6 O- _{C 2 H 4 O-CO-} C (CH 3) = CH 2, -C 3 H 6 O-C 6 H 11 (O-CO-CH = CH 2) 2, -C 3 H 6 O-C 6 H ₁₁ (O—CO—C (CH ₃ ) ═CH ₂ ) ₂ and the like may include those containing a (meth) acryloxy group bonded to an aromatic ring or an alkyl group. These can have 1 type, or 2 or more types.

  The content of the hydroxyl group-modified and / or (meth) acryloxy group-modified silicone oil (E) is usually 0.05 to 2.0 parts by weight, preferably 100 parts by weight of the powdered thermoplastic polyurethane (A), preferably 0.1 to 0.5 parts by weight. If the amount is less than 0.05 parts by weight, the effect of improving the mold releasability is not exhibited. The adhesion between the skin and the polyurethane foam is poor. The hydroxyl group-modified and / or (meth) acryloxy group-modified silicone oil (E) can be used alone or in combination of two or more.

  The method for producing a thermoplastic polyurethane resin composition for powder molding according to the present invention comprises a powdery thermoplastic polyurethane (A) and a powder colorant (B) containing a powder pigment (b1) and a pigment dispersant (b2). Then, the plasticizer (C) is added to and mixed with the resulting mixture. Thereafter, the resulting mixture is mixed with a hydroxyl group-containing aromatic vinyl copolymer (D) having an average particle diameter of 0.1 to 10 μm. Is added and mixed.

  In the production method of the present invention, the powdery thermoplastic polyurethane (A), the powder colorant (B) containing the powder pigment (b1) and the pigment dispersant (b2), the plasticizer (C), and the hydroxyl group-containing aromatic vinyl copolymer The mixing of the polymer (D) is not particularly limited except for the order of mixing described above. It is preferable to mix by high-speed stirring. Any mixing device can be used, but it is preferable to use a high-speed stirring device having a function of stirring at high speed and mixing powders, such as a Henschel mixer (trade name).

The stirring speed when mixing the powdered thermoplastic polyurethane (A) and the powder colorant (B) with a Henschel mixer or the like varies depending on the processing capacity (internal volume) of the mixer, but is preferably 100 to 5000 rpm. By mixing at such a stirring speed, the dispersion of the powder colorant (B) tends to be uniform, and melting of the powdered thermoplastic polyurethane (A) due to overheating or the like can be prevented.
The stirring time is preferably 30 seconds to 10 minutes. By mixing with such a stirring time, the dispersion of the powder colorant (B) tends to be uniform, and melting of the powdered thermoplastic polyurethane (A) due to overheating or the like can be prevented.
The stirring is preferably performed at room temperature, but some heat is generated due to high shear.

The stirring speed when adding a plasticizer (C) to a mixture of powdered thermoplastic polyurethane (A) and powder colorant (B) and mixing with a Henschel mixer or the like is the processing capacity (internal volume) of the mixer. ), The optimum stirring speed varies, but it is preferably 100 to 5000 rpm. By mixing at this stirring speed, the dispersion of the plasticizer (C) is good, and overheating and the melting of the powdery thermoplastic polyurethane (A) or the volatilization of the plasticizer (C) can be prevented.
The stirring time is preferably 1 minute to 30 minutes. By mixing with this stirring time, the dispersion of the plasticizer (C) is good, and overheating and the melting of the powdered thermoplastic polyurethane (A) or the volatilization of the plasticizer (C) can be prevented.
The stirring is desirably performed at room temperature, but the powdered thermoplastic polyurethane (A) can also promote the absorption of the plasticizer (C) by heating the wall surface of the mixer. Note that heat generation of the powder resin is somewhat caused by high shear.

A powdery thermoplastic polyurethane (A) and a powder colorant (B) are mixed, and then a plasticizer (C) is added and mixed. Further, a hydroxyl group-containing aromatic vinyl copolymer (D) is added. The stirring speed at the time of mixing with a Henschel mixer or the like is preferably 100 to 5000 rpm, although the optimum stirring speed varies depending on the processing capacity (internal volume) of the mixer. By mixing at this stirring speed, the dispersion of the hydroxyl group-containing aromatic vinyl copolymer (D) is good, and overheating and melting of the powdery thermoplastic polyurethane (A) or volatilization of the plasticizer (C) are caused. Can be prevented.
The stirring time is preferably 30 seconds to 10 minutes. By mixing with this stirring time, the dispersion of the hydroxyl group-containing aromatic vinyl copolymer (D) is good, and overheating and melting of the powdered thermoplastic polyurethane (A) or volatilization of the plasticizer (C) are caused. Can be prevented.
The stirring is desirably performed at room temperature, but some heat is generated due to high shear.

  The average particle diameter of the thermoplastic polyurethane resin composition for powder molding of the present invention is preferably 50 to 500 μm, more preferably 100 to 300 μm. If the average particle size is too small, it tends to agglomerate during powder storage, while if it is too large, the texture of the molded product becomes rough, and in the case of a molded product with a small thickness, pinholes are easily generated, which is not preferable.

  Such a thermoplastic polyurethane resin composition for powder molding of the present invention can be applied to powder slush molding and the like, and in particular, powder for surface layers of automobile interior parts such as instrument panels, headrests, console boxes, door trims, armrests and the like. It can be suitably used as a body molding material.

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples. The number of parts and% are based on weight unless otherwise specified.
The test method is as follows.

(1) Average particle diameter The average particle diameter of the powder is a particle diameter corresponding to an opening in which an integrated particle size distribution curve by a sieving method using a JIS standard sieve indicates 50% by weight.
(2) Powder flowability Using a bulk specific gravity measuring device defined in JIS K6721, the bulk specific gravity, the angle of repose in 100 ml of powder, and the flow-down speed in 100 ml of powder are measured. It can be said that the smaller the angle of repose and the faster the flow speed, the better the powder flowability.
(3) Meltability (a) In a 300 ° C. oven, an electroformed mold (150 × 180 × 3 mm) with a satin pattern (texture) is allowed to stand and when the mold temperature reaches 280 to 300 ° C. Remove the mold from the oven.
(B) When the mold surface temperature reaches 250 ° C. by being left in the room, 500 g of the thermoplastic polyurethane resin composition for powder molding is sprinkled on the mold and left to melt for 10 seconds.
(C) After removing the excess thermoplastic polyurethane resin composition for powder molding on the mold after 10 seconds, measure the time until the molten resin on the mold becomes smooth (leveling) at room temperature, This is the melting time. The shorter the melting time, the better the meltability.

(4) Urethane adhesion (adhesiveness between the skin formed by molding a thermoplastic polyurethane resin composition for powder molding and polyurethane foam)
(A) Powder molding material is made by a method for producing a skin (500 g of a thermoplastic polyurethane resin composition for powder molding is sprinkled on a 180 × 150 × 3 mm embossed mold heated to 250 ° C. and left as it is for 10 seconds. Immediately after that, the surplus composition is shaken off, and after 90 seconds, the mold is cooled with cooling water, and when the mold temperature is lowered to 40 ° C., the molded sheet is removed from the mold. The test piece of 180 mm × 25 mm is cut from the skin having a thickness of about 1 mm obtained in accordance with the above, and the test piece is formed into an aluminum mold with a lid having an inner dimension (vertical) 800 mm × (horizontal) 150 mm × (depth) 10 mm. The distance from the foamed polyurethane resin-forming liquid injection port to the far end face of the test piece was set to 600 mm, and the mold surface temperature was kept at 40 ° C.
(B) Next, 94.7 g of a foamed polyurethane forming liquid [polymeric MDI (4,4′-diphenylmethane diisocyanate functional group number: 2.7)] and a polyether polyol (trifunctional hydroxyl value: 50) were injected into the foamed polyurethane resin forming liquid injection port. 119.32 g of a mixture containing 1.0% triethylenediamine and 1.6% water), and the mold was closed and sealed. After holding the mold for 2 minutes and 30 seconds, the lid is opened, the test piece with the foamed polyurethane resin and the skin laminated is taken out, the skin is peeled off from the foamed polyurethane resin-forming liquid inlet side, and the distance where the cohesive failure (foamed layer failure) occurs Was measured. It shows that urethane adhesiveness is so favorable that the distance of the part which carried out the cohesive failure (foaming layer failure) is far. Urethane adhesion is indicated as follows.
○: 550 to 600 mm, Δ: 450 to 550 mm, ×: 450 mm or less.
(5) Demolding property 100 g of a thermoplastic polyurethane resin composition for powder molding is sprinkled on a 120 × 70 × 3 mm mold (mirror surface) heated to 250 ° C., and left to melt for 10 seconds. Immediately after that, the surplus composition was shaken off, and when 90 seconds passed, the mold was cooled with cooling water. When the mold temperature dropped to 40 ° C., the molded sheet was pulled from the mold at a rate of 20 mm / second. It peels at a speed | rate and measures the demolding force at that time (unit N / 70mm).

[Description of Polyester-1, Polyester-2, Polyester-3 Used for Synthesis of Powdered Thermoplastic Polyurethane (A)]
Polyester-1: An aromatic ring-free polyester polyol obtained from 1,4-butanediol and adipic acid. Hydroxyl value = 110 mgKOH / g, average functional group number = 2.
Polyester-2: An aromatic ring-containing polyester polyol obtained from isophthalic acid / azeleic acid = 1/1 (molar ratio) and ethylene glycol / neopentyl glycol = 9/1 (molar ratio). Hydroxyl value = 56 mg KOH / g, aromatic ring content = 1.97 mmol / g, average number of functional groups = 2.
Polyester-3: An aromatic ring-free polyester polyol obtained from 3-methyl-1,5-pentanediol and adipic acid. Hydroxyl value 56 mgKOH / g, average number of functional groups 2.
[Description of dispersion medium used for synthesis of powdered thermoplastic polyurethane (A)]
Dispersion medium: paraffinic solvent, trade name: Shellsol 71 (manufactured by Shell Chemical Co., Ltd.). Boiling point 170-200 ° C.

[Synthesis of dispersion stabilizer used for synthesis of powdered thermoplastic polyurethane (A)]
(1) Synthesis of polyol having unsaturated bond in molecule In a reaction kettle equipped with a stirrer, thermometer, distillation tower, nitrogen gas introduction tube, 1,000 parts by weight of polyester-1 and 49 parts of maleic anhydride A part by weight was charged and mixed with heating while flowing nitrogen gas. After reacting at a temperature of 140 to 160 ° C. and removing condensed water from the system, the reaction was further continued while gradually reducing the pressure inside the system, and finally the reaction was performed at 190 ° C. and 30 mmHg for 4 hours. The reaction was terminated. The obtained polyol had a hydroxyl value of 53 mgKOH / g and an acid value of 4.1 mgKOH / g. This polyol had a number average molecular weight of 2,100 and an average of one double bond in one molecule.
(2) Synthesis of dispersion stabilizer 44 parts by weight of the polyol synthesized in (1) and 99 parts by weight of butyl acetate were charged into a reaction kettle equipped with a stirrer, a thermometer, a dropping funnel, and a cooler. Heat and mix while flowing nitrogen gas into the system from the top of the dropping funnel. When the temperature reached 110 ° C., dropping of a dissolved mixture of 102 parts by weight of lauryl methacrylate and 2 parts by weight of benzoyl peroxide was started from the dropping funnel. The dropwise addition was completed in 1 hour and a half, and then the reaction was terminated at 130 ° C. for 2 hours. The hydroxyl value of this dispersion stabilizer was 11 mgKOH / g.

[Synthesis of powdered thermoplastic polyurethane (A)]
In a reaction kettle equipped with a high-speed specification stirring motor, 18.2 parts by weight of the dispersion stabilizer described above, 51.7 parts by weight of polyester-2 heated to 100 ° C., 23.0 parts by weight of polyester-3, Then, 5.9 parts by weight of 4-butanediol and 0.002 parts by weight of dibutyltin dilaurate were added and mixed uniformly, then 100.0 parts by weight of the above-mentioned dispersion medium was added, and high-speed stirring was performed for 10 minutes. Next, 17.4 parts by weight of hexamethylene diisocyanate was charged, heated to 80 ° C. and reacted for 4 hours. Then, the dispersion medium and the resin were separated by a centrifugal dehydrator and dried under reduced pressure. 99.5 parts by weight of true spherical powdered thermoplastic polyurethane (A-1) having a number average molecular weight Mn = 27,000 was obtained.

[Powder colorant (B-1)]
PV-7A1301 (mixture of titanium oxide as a powder pigment and calcium carbonate as a pigment dispersant in a ratio of 70/30) manufactured by Sumika Color Co., Ltd. was used as a powder colorant (B-1).

[Powder colorant (B-2)]
PV-817 manufactured by Sumika Color Co., Ltd. (a mixture of carbon black as a powder pigment and calcium carbonate as a pigment dispersant in a ratio of 40/60) was used as a powder colorant (B-2).

[Production of hydroxyl group-containing aromatic vinyl copolymer (D)]
200 parts of distilled water was charged into a 10-liter stainless steel premixing vessel having two-stage blades. Furthermore, 40 parts of a monomer mixture comprising 35% by weight of styrene, 30% by weight of 2-hydroxypropyl methacrylate (HPMA), and 35% by weight of methyl methacrylate (MMA), 1.0 part of a linear higher alcohol having 18 carbon atoms After adding 0.5 part of sodium lauryl sulfate and 0.3 part of benzoyl peroxide and mixing at 30 ° C. for 1 hour, the suspension formed by stirring is passed through a homogenizer and then has a two-stage blade. It was transferred into another 10 liter stainless steel pressure vessel and subjected to fine suspension polymerization at 60 ° C. to produce a hydroxyl group-containing aromatic vinyl copolymer. The polymerization conversion was 98%. The average particle diameter of the obtained hydroxyl group-containing aromatic vinyl copolymer (D-1) was 2.2 μm.

[Mixing of powdered thermoplastic polyurethane (A-1) and powder colorants (B-1, B-2)]
In a Henschel mixer having an internal volume of 10 liters, 100 parts by weight of the powdered thermoplastic polyurethane (A-1), 1.8 parts by weight of the powder colorant (B-1), and 0.18 of the powder colorant (B-2) Part by weight was added and mixed at 1000 rpm for 1 minute to obtain a mixture of powdered thermoplastic polyurethane (A-1) and powder colorants (B-1, B-2).

[Preparation of thermoplastic polyurethane resin composition for powder molding]
In a state where the mixture of the powdery thermoplastic polyurethane (A-1) and the powder colorant (B-1, B-2) is contained in a Henschel mixer having an internal volume of 10 liters, a plasticizer (C- 1) 5 parts by weight of RS-107 (adipic acid diester system: manufactured by Asahi Denka Kogyo Co., Ltd.) was added and mixed at 1000 rpm for 5 minutes. 3 parts by weight of the vinyl group copolymer (D-1) was added and further mixed at 1000 rpm for 1 minute to obtain a thermoplastic polyurethane resin composition for powder molding. About the obtained thermoplastic polyurethane resin composition for powder molding, powder fluidity, meltability, urethane adhesiveness, and demoldability were measured. The results are shown in Table 1.

  FM-0725 [one-end methacryloxy group-modified silicone oil as methacryloxy group-modified silicone oil (E-1) together with plasticizer (C-1) RS-107 when producing a thermoplastic polyurethane resin composition for powder molding (Product name: Silaplane): manufactured by Chisso Corp.] The same operations as in Example 1 were performed except that 0.3 parts by weight was added and mixing was performed to obtain a thermoplastic polyurethane resin composition for powder molding. Obtained. The results are shown in Table 1.

[Comparative Example 1]
Instead of the hydroxyl group-containing aromatic vinyl copolymer (D-1), 3 parts by weight of a hydroxyl group-containing aromatic vinyl copolymer having an average particle size of 50 μm and the same monomer unit composition as D-1 A thermoplastic polyurethane resin composition for powder molding was produced by performing the same operation as in Example 1 except that was used. The results are shown in Table 1.

[Comparative Example 2]
The same procedure as in Example 1 was performed except that 3 parts by weight of acrylic resin powder Hibrene B409S (manufactured by Nippon Zeon Co., Ltd.) was used instead of the hydroxyl group-containing aromatic vinyl copolymer (D-1). A thermoplastic polyurethane resin composition for molding was prepared. The results are shown in Table 1.

[Comparative Example 3]
Powder molding was carried out in the same manner as in Example 1 except that 3 parts by weight of Aerosil A200 (particulate silica; manufactured by Nippon Aerosil Co., Ltd.) was used instead of the hydroxyl group-containing aromatic vinyl copolymer (D-1). A thermoplastic polyurethane resin composition was prepared. The results are shown in Table 1.

From the results in Table 1, the following can be said.
In producing a thermoplastic polyurethane resin composition for powder molding, a hydroxyl group containing an average particle size of 50 μm is used instead of the hydroxyl group containing aromatic vinyl copolymer (D-1) having an average particle size of 2.2 μm. In Comparative Example 1 using the aromatic vinyl copolymer and Comparative Example 2 using the acrylic resin powder Hibrene B409S, the urethane adhesion was poor.
Further, in Comparative Example 3 using fine particle silica Aerosil A200 instead of the hydroxyl group-containing aromatic vinyl copolymer (D-1), the meltability and urethane adhesiveness were poor.

  In comparison with the thermoplastic polyurethane resin composition for powder molding produced in Example 1, the powder fluidity, the meltability, and the urethane adhesiveness were good. Moreover, in Example 2 to which methacryloxy group-modified silicone oil (E-1) was added, the demoldability was further improved.

Claims (3)

100 parts by weight of powdered thermoplastic polyurethane (A),
A powder colorant (B) comprising a powder pigment (b1) and a pigment dispersant (b2);
A plasticizer (C);
1-20 parts by weight of copolymer (D) of aromatic vinyl monomer, hydroxyl group-containing vinyl monomer, and any other copolymerizable monomer having an average particle size of 0.1-10 μm Ri name containing the door,
Hydroxyl group-containing vinyl in a copolymer (D) of an aromatic vinyl monomer, a hydroxyl group-containing vinyl monomer, and any other copolymerizable monomer having an average particle size of 0.1 to 10 μm the content of the monomer units are Ru 20-50 wt% der, for powder molding the polyurethane resin composition.   The polyurethane resin composition for powder molding according to claim 1, further comprising a hydroxyl group-modified and / or (meth) acryloxy group-modified silicone oil (E). Powdered thermoplastic polyurethane (A);
The powder colorant (B) containing the powder pigment (b1) and the pigment dispersant (b2) is mixed, and then the resulting mixture is
The plasticizer (C) is added and mixed, and then the resulting mixture is
A copolymer (D) of an aromatic vinyl monomer, a hydroxyl group-containing vinyl monomer, and any other copolymerizable monomer having an average particle size of 0.1 to 10 μm, 1 to 20 parts by weight added to 100 parts by weight of plastic polyurethane (A) and mixed ,
Hydroxyl group-containing vinyl in a copolymer (D) of an aromatic vinyl monomer, a hydroxyl group-containing vinyl monomer, and any other copolymerizable monomer having an average particle size of 0.1 to 10 μm Content of a monomer unit is 20 to 50 weight%, The manufacturing method of the thermoplastic polyurethane resin composition for powder molding characterized by the above-mentioned.