JP4780267B2 - Thermoplastic polyurethane resin composition for powder molding and method for producing the same - Google Patents

Description

  The present invention relates to a resin composition for powder molding, and more specifically, a powder that gives a molded article excellent in demoldability, low mold contamination, and adhesiveness with foamed polyurethane without impairing powder flowability. The present invention relates to a molding thermoplastic polyurethane resin composition and a method for producing the same.

  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, thermoplastic polyurethane resins for powder molding have problems with demoldability, low mold contamination, adhesiveness with foamed polyurethane, and powder fluidity necessary to ensure uniform thickness. It was. In particular, with regard to demoldability, attempts to impart demoldability with fatty acid metal salts (see Patent Document 1), fluorine-based release agents, silicone-based release agents (amino-modified dimethylpolysiloxane, carboxy-modified dimethyl) Polysiloxane, dimethylpolysiloxane), fatty acid ester release agents, and phosphate ester release agents have been tried (see Patent Document 2). However, in the invention described in Patent Document 1, the metal salt is transferred to the mold at the time of slush molding, the demolding property is deteriorated, and the mold contamination property is deteriorated. However, the problem of poor adhesion to foamed polyurethane remains, and there is a need for a solution.

JP 2001-019863 A JP-A-10-338733

  The present invention has been made in view of the above-described circumstances, and the object of the present invention is to provide a powder necessary for ensuring demoldability, low mold contamination, adhesiveness with foamed polyurethane, and uniform wall thickness. The object is to provide a thermoplastic polyurethane resin composition for powder molding excellent in body fluidity and a method for producing the same.

  As a result of diligent studies to achieve the above object, the present inventors have found that a powdery thermoplastic polyurethane, a powder colorant including a powder pigment and a pigment dispersant, a plasticizer, a hydroxyl group-modified and / or (meth) acryloxy Necessary for molding a thermoplastic polyurethane resin composition for powder molding containing a group-modified silicone oil into a moldable, low mold fouling property, adhesiveness with foamed polyurethane, and uniform thickness Based on this finding, the present inventors have completed the present invention.

Thus, according to the present invention, powdered thermoplastic polyurethane (A), powder colorant (B) containing powder pigment (b1) and pigment dispersant (b2), plasticizer (C), hydroxyl-modified and / or Alternatively, a polyurethane resin composition for powder molding comprising a (meth) acryloxy group-modified silicone oil (D) is provided.
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 Provided is a method for producing a thermoplastic polyurethane resin composition for powder molding, which comprises adding and mixing a plasticizer (C) and a hydroxyl group-modified and / or (meth) acryloxy group-modified silicone oil (D). Is done.

  According to the present invention, powder molding of the skin material of automobile interior parts such as instrument panels, headrests, console boxes, door trims, armrests, etc. is easy, mold release during molding, mold contamination, foamed polyurethane and There is provided a thermoplastic polyurethane resin composition for powder molding which gives a powder molded article having excellent adhesiveness and powder flowability necessary for ensuring uniform wall thickness.

  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-modified and / or (meth) acryloxy group-modified silicone oil (D).

  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) Condensation polymerization of low-molecular polyols and / or polyether polyols with carbonic diesters (dimethyl carbonate, ethylene carbonate, etc.); and mixtures of two or more of these It is done.

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 , These alkylene oxide adducts (hydroxyl equivalents less than 250); and mixtures of two or more thereof.
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 and the like) and combinations of two or more thereof (block and / or random addition). Preference is given to EO, PO and combinations thereof (block and / or random addition).

  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; and mixtures of two or more thereof.

  Examples of the lactone monomer (2) include lactones having 4 to 12 carbon atoms, such as γ-butyrolactone, ε-caprolactone, γ-valerolactone, and mixtures of two or more thereof.

  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 combinations of two or more of these.

  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) glycol, polyoxybutylene-polyoxypropylene (block and / or random) glycol, EO and / or PO adducts of bisphenol A, and combinations of two or more thereof.

  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.

  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;

  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-modified and / or (meth) acryloxy group-modified silicone oil (D) is added to improve the releasability, but the hydroxyl group-modified silicone oil and / or (meth) acryloxy group-modified silicone oil [ "(Meth) acryloxy group" refers to a methacryloxy group and / or an acryloxy group]. In a silicone oil that has been conventionally used, a predetermined amount thereof is contained in a thermoplastic polyurethane resin composition for powder molding. Has improved the adhesion between the polyurethane foam and polyurethane foam formed by molding a thermoplastic polyurethane resin composition for powder molding.

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

  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 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). Next, the plasticizer (C) and the hydroxyl group-modified and / or (meth) acryloxy group-modified silicone oil (D) are added to and mixed with the resulting mixture.

  In the production method of the present invention, powdered thermoplastic polyurethane (A), powder colorant (B) containing powder pigment (b1) and pigment dispersant (b2), plasticizer (C), and hydroxyl-modified and / or ( Mixing of the (meth) acryloxy group-modified silicone oil (D) is not particularly limited except for the mixing order described above. The stirring speed in mixing is preferably mixing 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.
In addition, although stirring is normally performed at room temperature, the heat_generation | fever by high shear arises a little.

A Henschel mixer is prepared by adding a plasticizer (C) and a hydroxyl group-modified and / or (meth) acryloxy group-modified silicone oil (D) to a mixture of a powdered thermoplastic polyurethane (A) and a powder colorant (B). The mixing speed at the time of mixing is preferably 100 to 5000 rpm, although the optimal stirring speed varies depending on the processing capacity (internal volume) of the mixer. By mixing at this stirring speed, the dispersion of the plasticizer (C) and the hydroxyl group-modified and / or (meth) acryloxy group-modified silicone oil (D) is good, and overheating and powdered thermoplastic polyurethane (A ) Melting or plasticizer (C) or hydroxyl group-modified and / or (meth) acryloxy group-modified silicone oil (D) can be prevented from volatilizing.
The stirring time is preferably 1 minute to 30 minutes. By mixing with this stirring time, the dispersion of the plasticizer (C) and the hydroxyl group-modified and / or (meth) acryloxy group-modified silicone oil (D) is good, and overheating and powdered thermoplastic polyurethane (A ) Melting or plasticizer (C) or hydroxyl group-modified and / or (meth) acryloxy group-modified silicone oil (D) can be prevented from volatilizing.
The stirring is preferably performed at room temperature, but by heating the wall surface of the mixer, the powdered thermoplastic polyurethane (A) becomes the plasticizer (C) and the hydroxyl group-modified and / or (meth) acryloxy group-modified silicone. Absorption of oil (D) can also be promoted. Note that heat generation of the powder resin is somewhat caused by 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) 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).
(4) Mold fouling property The powder molding material was coated with 500 g of a thermoplastic polyurethane resin composition for powder molding on a 180 × 150 × 3 mm embossed mold heated to 250 ° C. The excess composition is shaken off immediately after that, and when 90 seconds have passed, the mold is cooled with cooling water, and when the mold temperature is lowered to 40 ° C., the molded sheet is molded into the mold. The mold contamination state at that time was judged by the following index.
○: Almost no change from the initial contamination state, or a slight change in hue.
Δ: Hue is clearly changed or gloss is clearly changed.
×: Hue and gloss are remarkably changed, and residue of the skin is adhered.
(5) Urethane adhesiveness (adhesiveness between the skin formed by molding a thermoplastic polyurethane resin composition for powder molding and foamed polyurethane)
(A) A 180 mm × 25 mm test piece was cut out from a skin having a thickness of about 1 mm obtained from the powder molding material according to the method for producing a skin described in (4) above, and the test piece was cut into an inner dimension (vertical) 800 mm × ( Horizontal) Place in a 150 mm x 10 mm deep aluminum mold with a lid so that the distance from the foamed polyurethane resin-forming liquid injection port to the far end surface of the test piece is 600 mm, and the mold surface temperature is 40 ° C. Was kept.
(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.

[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).

[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 colorant (B-1).

[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) RS-107 (adipic acid diester type: Asahi Denka Kogyo Co., Ltd.) 5 parts by weight, and methacryloxy group-modified silicone oil (D-1) FM-0725 [one-end methacryloxy group-modified silicone oil (product) Name: Silaplane): Chisso Co., Ltd.] 0.3 parts by weight of plasticizer and silicone oil were added in this order, mixed at 1000 rpm for 5 minutes, and then used as a dusting agent, Hybrene B409S (Nihon Zeon Co., Ltd.) 3 parts by weight were added and mixed at 1000 rpm for another 1 minute to obtain a thermoplastic polyurethane resin composition for powder molding. With respect to the obtained thermoplastic polyurethane resin composition for powder molding, powder flowability, meltability, demoldability, and colorability were measured. The results are shown in Table 1.

  Instead of methacryloxy group-modified silicone oil (D-1) FM-0725, FM-0425 [one-end hydroxyl group-modified silicone oil (trade name: Silaplane): Chisso Corporation as a hydroxyl group-modified silicone oil (D-2) [Product] A thermoplastic polyurethane resin composition for powder molding was prepared in the same manner as in Example 1 except that 0.3 parts by weight was used. The results are shown in Table 1.

[Comparative Example 1]
Implementation was performed except that 0.3 part by weight of SH-200 (polydimethylsiloxane: Shin-Etsu Silicone Co., Ltd.) was used as polydimethylsiloxane instead of methacryloxy group-modified silicone oil (D-1) FM-0725. The same operation as in Example 1 was performed to prepare a thermoplastic polyurethane resin composition for powder molding. The results are shown in Table 1.

[Comparative Example 2]
Example 1 except that 0.3 parts by weight of FZ-3720 (manufactured by Nippon Unicar Co., Ltd.) was used as an epoxy group-modified silicone oil instead of methacryloxy group-modified silicone oil (D-1) FM-0725. The same operation was performed to produce a thermoplastic polyurethane resin composition for powder molding. The results are shown in Table 1.

[Comparative Example 3]
Example 1 except that 0.3 parts by weight of amino group-modified silicone oil FZ-3760 (manufactured by Nippon Unicar Co., Ltd.) was used instead of methacryloxy group-modified silicone oil (D-1) FM-0725. Thus, a thermoplastic polyurethane resin composition for powder molding was produced. The results are shown in Table 1.

[Comparative Example 4]
Instead of methacryloxy group-modified silicone oil (D-1) FM-0725, the same as in Example 1 except that 0.3 part by weight of zinc stearate (SZ-2000: manufactured by Sakai Chemical Co., Ltd.) was used. The operation was performed to produce a thermoplastic polyurethane resin composition for powder molding. 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, Comparative Example 1 using polydimethylsiloxane, epoxy group-modified silicone oil was used instead of hydroxyl group-modified or (meth) acryloxy group-modified silicone oil (D). In Comparative Example 2 and Comparative Example 3 using an amino group-modified silicone oil, urethane adhesion (adhesiveness between a sheet formed from a thermoplastic polyurethane resin composition for powder molding and foamed polyurethane) was obtained. It was bad.

  Further, in Comparative Example 4 in which zinc stearate was used instead of the hydroxyl group-modified and / or (meth) acryloxy group-modified silicone oil (D), all of the demolding property, mold contamination property, and urethane adhesiveness were poor. Met. In demoldability, the epidermis was destroyed without demolding from the mold.

  In comparison, the thermoplastic polyurethane resin composition for powder molding produced in the examples had good powder flowability, demoldability, low mold contamination, and urethane adhesion.

Claims (2)

A powder resin other than the dusting agent and consisting only of powdered thermoplastic polyurethane (A),
A powder colorant (B) containing a pigment dispersant (b2) comprising a powder pigment (b1) and an inorganic dispersant;
A plasticizer (C);
A polyurethane resin composition for powder molding comprising a hydroxyl group-modified and / or (meth) acryloxy group-modified silicone oil (D). A powder resin other than the dusting agent and consisting only of powdered thermoplastic polyurethane (A),
The powder pigment (b1) and the powder colorant (B) containing the pigment dispersant (b2) comprising an inorganic dispersant are mixed, and then the resulting mixture is
A plasticizer (C);
A method for producing a thermoplastic polyurethane resin composition for powder molding, comprising adding a hydroxyl group-modified and / or (meth) acryloxy group-modified silicone oil (D) and mixing them.