JP2010059314A - Foaming powdery thermoplastic polyurethane resin composition, sheet-like polyurethane resin molded product having double layer structure using the same, and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet-like polyurethane resin molded product which has a soft touch feeling, and excellent abrasion resistance and mechanical properties, achieves weight reduction of a molded product and cost reduction, and has a double layer structure having a high designability of a non-foamed layer and a foamed layer, by use of a foaming powdery thermoplastic polyurethane resin composition with excellent powder flowability. <P>SOLUTION: A powdery thermoplastic polyurethane resin (A1) constituting the foaming powdery thermoplastic polyurethane resin composition (A) has a volume-average particle diameter of 110 to 300 μm, a content of particles of less than 100 μm of ≤40 mass%, that of less than 30 μm of ≤5 mass%, and that of less than 20 μm of ≤2 mass%. The sheet-like polyurethane resin molded product has a double layer structure of a non-foamed layer and a foamed layer using the urethane resin composition. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a foamable powdered thermoplastic polyurethane resin composition, a sheet-like polyurethane resin molded article having a two-layer structure using the same, and a method for producing the same. More specifically, it has a two-layer structure with a highly-designed foam layer and non-foam layer that has a soft tactile feel, excellent wear resistance, mechanical properties, etc., and realizes weight reduction and cost reduction of the molded product. The present invention relates to a foamable powdered thermoplastic polyurethane resin composition capable of obtaining a sheet-like molded article having the same, a sheet-like polyurethane resin molded article having a two-layer structure using the same, and a method for producing the same.

  The slush molding method is widely used for automobile interior materials and the like because it can efficiently form a uniform product with high design and high wall thickness due to excellent powder flowability. Recently, a powdered thermoplastic polyurethane resin excellent in flexibility has been adopted as a slush molding material.

It is known that the powder flowability of the powdered thermoplastic polyurethane resin material is greatly influenced by the shape of the particles and the volume average particle diameter, and is particularly strongly dependent on the abundance of small diameter particles of less than 100 μm. In Patent Document 1, it is clearly stated that the proportion of particles having a particle size of less than 75 μm is 20% by mass or less, preferably 15% by mass or less, regarding the powder flowability of the powdered thermoplastic polyurethane resin material and the moldability associated therewith. Has been.
JP-A-2003-300428

  As a method for softening a resin, a method for improving the flexibility by adding a plasticizer having a relatively low molecular weight to the resin is widely known.

In addition, for the purpose of softening and reducing the weight of the resin, for example, as in Patent Document 2, a composite foam molded product is formed in which the outer skin is formed of a plastisol containing no foaming agent and the inner foam layer is formed of a plastisol containing a foaming agent. The method of doing is known conventionally.
Japanese Patent Publication No. 63-27167

  However, when storing a powdered thermoplastic polyurethane resin material, there is a problem that the primary particles agglomerate and solidify due to the thermal history applied to the material during thermoforming, and the powder flowability deteriorates and causes molding defects. It has been.

  Resin containing a plasticizer as a method for softening the resin has a problem of fogging due to volatilization of the plasticizer in long-term use, loss of softness due to migration of the plasticizer to the surface of the molded product, and deterioration of durability. It is a problem.

  In addition, some general organic pyrolytic foaming agents used in foamed molded products generate harmful gases and harmful substances as decomposition by-products. Requires special consideration. For example, 2,2'-azobisisobutyronitrile (AIBN) has a risk of explosion due to impact, friction, fire or the like, and contains an organic cyanide as a decomposition byproduct.

  The present invention has been made based on the above situation. The object of the present invention is to provide a design that has a soft tactile sensation by using a small amount of pyrolytic foaming agent, has excellent wear resistance, mechanical properties, etc., and realizes weight reduction and cost reduction of the molded product. Foamable thermoplastic polyurethane resin composition capable of obtaining a sheet-like molded article having a two-layer structure of a highly foamed layer and a non-foamed layer, and a sheet-like polyurethane resin molding having a two-layer structure using the same It is in providing a thing and its manufacturing method.

  That is, this invention is shown to the following (1)-(12).

(1) In the foamable powdered thermoplastic polyurethane resin composition (A) obtained by compounding the powdered thermoplastic polyurethane resin (A1) with the powdered pyrolytic foaming agent (A2),
The volume average particle diameter of the powdered thermoplastic polyurethane resin (A1) is 110 to 300 μm, the content of particles less than 100 μm is 40% by mass or less, and the content of particles less than 30 μm is 5% by mass or less, and The content of particles less than 20 μm is 2% by mass or less,
The volume average particle size of the powdered pyrolytic foaming agent (A2) is 20 μm or less,
A foamable powdered thermoplastic polyurethane resin composition (A) characterized by

(2) The bulk specific gravity is 0.60 g / cm ³ or more, and 100 cm ³ (A) flows down the funnel having an outlet inner diameter of 8 mm for 20 seconds or less. A foamable powdered thermoplastic polyurethane resin composition (A).

(3) The foamable powdered thermoplastic polyurethane resin composition (A) according to the above (1) or (2), wherein the angle of repose is 35 ° or less.

(4) The foamable powdered thermoplastic polyurethane resin composition (A) according to any one of the above (1) to (3), wherein the pass rate when the blocking rate is measured is 50% or more.

(5) The powdered pyrolytic foaming agent (A2) is an organic pyrolytic foaming agent (A2-1), and the organic pyrolytic foaming agent (A2-1) is a powdered thermoplastic polyurethane resin. The foamable powdery thermoplastic polyurethane resin according to any one of the above (1) to (4), which is compounded at a ratio of 0.2 to 1.0% by mass with respect to (A1) Composition (A).

(6) The powdered pyrolyzable foaming agent (A2) is an inorganic pyrolyzable foaming agent (A2-2), and the inorganic pyrolyzable foaming agent (A2-2) is a powdered thermoplastic polyurethane resin. It is compounded in the ratio of 1.0-4.5 mass% with respect to (A1), The foamable powdery thermoplastic polyurethane resin in any one of said (1)-(4) characterized by the above-mentioned. Composition (A).

(7) A foamed layer (a) obtained by molding the foamable powdered thermoplastic polyurethane resin composition (A) according to any one of the above (1) to (6), and a non-foamable powdered thermoplastic containing no foaming agent A sheet-like polyurethane resin molded article having a two-layer structure of a non-foamed layer (b) obtained by molding the polyurethane resin composition (B).

(8) The thickness ratio of the foamed layer (a) is 0.4 to 0.00 with respect to the total thickness of the sheet-like polyurethane resin molded article having a two-layer structure composed of the foamed layer (a) and the non-foamed layer (b). 92. A sheet-like polyurethane resin molded article having the two-layer structure of (7) above, which is 92.

(9) After the non-foamable powdery thermoplastic polyurethane resin composition (B) is melted on the mold surface, the foamable powdery thermoplastic polyurethane resin of any one of (1) to (6) above A method for producing a sheet-like polyurethane resin molding having a two-layer structure, comprising laminating the composition (A) and melting and foaming a powder resin by heating to integrally form a non-foamed layer and a foamed layer .

(10) After the non-foamable powdery thermoplastic polyurethane resin composition (B) is melted on the mold surface, the foamable powdery thermoplastic polyurethane resin according to any one of (1) to (6) above The composition (A) is laminated, and the powder resin is melted and foamed by heating, and the total thickness of the sheet-like polyurethane resin molding having a two-layer structure comprising the non-foamed layer (b) and the foamed layer (a) And a non-foamed layer and a foamed layer are integrally formed so that the thickness ratio of the foamed layer (a) is 0.4 to 0.92. Manufacturing method.

(11) The method for producing a sheet-like polyurethane resin molded article having the two-layer structure according to (9) or (10), wherein the following three steps are performed.
First step: A non-foamable powdered thermoplastic polyurethane resin composition (B) is charged into a mold preheated to 200 ° C. to 300 ° C., and the mold is inverted to remove excess powder material. A process of attaching and melting (B) with a uniform thickness on the mold surface. Second process: The foamable powdered thermoplastic polyurethane resin composition (A) is charged while (B) is attached to the mold. Inverting the mold to remove excess powder material and depositing (A) on the layer (B) with a predetermined thickness Third step: (A) layer in a heating oven at 200 to 400 ° C. And (B) the layered and adhered mold is placed for 30 to 120 seconds to complete the melting and foaming of the powdered resin, and then taken out of the heating oven and cooled to mold, and then the molded product is demolded. Process

(12) The method for producing a sheet-like polyurethane resin molded article having the two-layer structure according to (9) or (10), wherein the following three steps are performed.
First step: A non-foamable powdered thermoplastic polyurethane resin composition (B) is charged into a mold preheated to 200 ° C. to 300 ° C., and the mold is inverted to remove excess powder material. A process of attaching and melting (B) with a uniform thickness on the mold surface. Second process: The foamable powdered thermoplastic polyurethane resin composition (A) is charged while (B) is attached to the mold. The process of inverting the mold to remove excess powder material and depositing (A) on the layer (B) with a predetermined thickness Third process: (A) layer and (B) layer are laminated and adhered The mold is self-heated at 200 ° C. to 300 ° C. for 30 to 120 seconds to complete the melting and foaming of the powder resin, and then the mold is cooled and then the molded product is demolded

  According to the present invention, a sheet having a soft tactile feel, excellent wear resistance, mechanical properties, etc., and having a two-layer structure of a foamed layer and a non-foamed layer with high design that realizes weight reduction and cost reduction of a molded product. It has become possible to provide a foamable powdered thermoplastic polyurethane resin composition capable of obtaining a molded article, a sheet-like polyurethane resin molded article having a two-layer structure using the same, and a method for producing the same.

A foamable powdered thermoplastic polyurethane resin composition for forming a foamed layer (a) in a sheet-like polyurethane resin molded product having a two-layer structure comprising a non-foamed layer (b) and a foamed layer (a) used in the present invention The volume average particle diameter of the powdered thermoplastic polyurethane resin constituting (A) is 110 to 300 μm, preferably 110 to 200 μm. When the volume average particle size is excessive, pinholes are likely to occur in the undercut portion and the corner portion of the obtained molded product. On the other hand, when the volume average particle size is too small, flowability and powder breakage are deteriorated, and the thickness of the obtained molded product tends to be non-uniform.
Here, the “volume average particle size” refers to a cumulative percent value of 50% in a particle size distribution (volume distribution) curve measured by a laser diffraction particle size analyzer.

  Further, the powdered thermoplastic polyurethane resin constituting the foamable powdered thermoplastic polyurethane resin composition (A) has a content of particles of less than 100 μm of 40% by mass or less and a content of particles of less than 30 μm of 5 It is important that the content of particles of less than 20% by mass and less than 20 μm is 2% by mass or less. When the particle diameter is outside this range, the powder fluidity of the powdered thermoplastic polyurethane resin is deteriorated, which tends to cause molding defects. In addition, it becomes difficult to form a foam layer having a uniform thickness. The particle size is a value measured by a laser diffraction particle size analyzer.

  The repose angle of the foamable powdered thermoplastic polyurethane resin composition (A) of the present invention is preferably 35 ° or less, more preferably 33 ° or less. When the angle of repose is excessive, the flowability at the time of molding is deteriorated, and molding defects are likely to occur.

  The pass rate in the blocking resistance of the foamable powdery thermoplastic polyurethane resin composition (A) of the present invention is preferably 50% or more. When the pass rate is 50% or less, the powder fluidity can be reduced by storing powdered thermoplastic polyurethane resin material or by blocking the primary particles by agglomeration and solidification due to the thermal history applied to the material during thermoforming. It deteriorates and tends to cause molding defects particularly when continuous molding is performed.

  The foamable powdered thermoplastic polyurethane resin of the present invention preferably has a spherical shape with good fluidity (flowability during molding). The ratio of the minor axis to the major axis (minor axis / major axis) is preferably from 0.5 to 1.0, particularly preferably from 0.8 to 1.0. When the shape is not spherical, the flowability at the time of molding is deteriorated, and molding defects are likely to occur.

  The non-foamable powdered thermoplastic polyurethane resin composition (B) derived from the non-foamed layer (b) of the present invention is a foamable powdered thermoplastic polyurethane resin composition (A) derived from the non-foamed layer (a). It is preferable to have a powder fluidity corresponding to.

Examples of the powdered thermoplastic polyurethane resin (A1) used in the present invention include those formed from isocyanate group-terminated prepolymers. As the isocyanate group-terminated prepolymer,
An isocyanate group-terminated prepolymer obtained by reacting a polymer polyol, an organic polyisocyanate, and a monofunctional active hydrogen group-containing compound (hereinafter also referred to as “isocyanate group-terminated prepolymer (I)”);
An isocyanate group-terminated prepolymer (hereinafter referred to as “isocyanate group-terminated prepolymer (II)” obtained by reacting a polymer polyol, an organic polyisocyanate, a monofunctional active hydrogen group-containing compound and a bifunctional active hydrogen group-containing compound (glycol). ) ").).

  The number average molecular weight of the polymer polyol used for obtaining the isocyanate group-terminated prepolymer is 500 or more, preferably 1,000 to 5,000. The kind of the polymer polyol is not particularly limited, and examples thereof include polymer polyols such as polyester polyol, polyesteramide polyol, polyether polyol, polyether / ester polyol, polycarbonate polyol, polyolefin polyol, and the like. Or used in combination. The polymer polyol in the present invention is preferably a polyester polyol.

  Examples of the polyester polyol and polyester amide polyol include polycarboxylic acids, polycarboxylic acid dialkyl esters, acid anhydrides, acid halides and other polycarboxylic acid derivatives, (number average) a low molecular polyol having a molecular weight of less than 500, a low molecular polyamine, It is obtained by a reaction with a low molecular active hydrogen group-containing compound such as a low molecular amino alcohol.

  Examples of the polycarboxylic acid include succinic acid, adipic acid, sebacic acid, azelaic acid, terephthalic acid, isophthalic acid, orthophthalic acid, phthalic anhydride, hexahydroterephthalic acid, hexahydroisophthalic acid and the like.

  Low molecular polyols include ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 2-methyl-1,3-propylene diol, 1,2-butane diol, 1,3-butane diol, 4-butanediol (hereinafter abbreviated as 1,4-BD), 1,5-pentanediol, 1,6-hexanediol (hereinafter abbreviated as 1,6-HD), 3-methyl-1,5-pentane Diol, neopentyl glycol, 1,8-octanediol, 1,9-nonanediol, 3,3-dimethylol heptane, diethylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 2-ethyl-1 , 3-propanediol, 2-normalpropyl-1, 3-propanediol, 2-isopropyl- 3-propanediol, 2-normalbutyl-1, 3-propanediol, 2-isobutyl-1, 3-propanediol, 2-tertiarybutyl-1, 3-propanediol, 2-methyl-2-ethyl- 1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-ethyl-2-normalpropyl-1,3-propanediol, 2-ethyl-2-normalbutyl-1,3-propane Diol, 2-ethyl-3-ethyl-1,4-butanediol, 2-methyl-3-ethyl-1,4-butanediol, 2,3-diethyl-1,5-pentanediol, 2,4-diethyl -1,5-pentanediol, 2,3,4-triethyl-1,5-pentanediol, trimethylolpropane, dimethylolpropionic acid, dimethyle Rubutan acid, dimer acid diol, glycerin, pentaerythritol, alkylene oxide adduct of bisphenol A and the like.

  Examples of the low molecular weight polyamine having a number average molecular weight of less than 500 include ethylenediamine, hexamethylenediamine, xylylenediamine, isophoronediamine, and ethylenetriamine.

  Examples of the low molecular amino alcohol having a number average molecular weight of less than 500 include monoethanolamine, diethanolamine, and monopropanolamine.

  Also suitable are polyester polyols such as lactone polyester polyols obtained by ring-opening polymerization of cyclic ester (lactone) monomers such as ε-caprolactone, alkyl-substituted ε-caprolactone, δ-valerolactone, and alkyl-substituted δ-valerolactone. Can be used.

  Examples of the polyether polyol include polyethylene glycol, polypropylene ether polyol, and polytetramethylene ether polyol.

  Examples of polyether ester polyols include polyester polyols produced from the above polyether polyols and the above polycarboxylic acid derivatives.

  The polycarbonate polyol is generally a deethanol condensation reaction of a low molecular polyol and diethyl carbonate, a demethanol condensation reaction of a low molecular polyol and dimethyl carbonate, a dephenol condensation reaction of a low molecular polyol and diphenyl carbonate, or a low molecular polyol. This low molecular polyol obtained by deethylene glycol condensation reaction of ethylene carbonate and the like includes the low molecular polyol used to obtain the above-mentioned polyester polyol.

  Specific examples of the polyolefin polyol include a hydroxyl group-terminated polybutadiene, a hydrogenated product thereof, and a hydroxyl group-containing chlorinated polyolefin.

  Preferred polymer polyols include polyester polyols, polyether polyols, and polycarbonate polyols having a number average molecular weight of 1,000 to 5,000, because the molded article obtained can exhibit good physical properties and feel. A polyester polyol having an average molecular weight of 1,000 to 5,000 is preferred, and a polyester polyol using 30 mol% or more of an aromatic dicarboxylic acid as an acid component is particularly preferred.

  As organic polyisocyanates, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylene-1,4-diisocyanate, xylene-1,3-diisocyanate, tetramethylxylene diisocyanate, 4,4'-diphenylmethane diisocyanate 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenyl ether diisocyanate, 2-nitrodiphenyl-4,4'-diisocyanate, 2,2'-diphenylpropane-4,4'- Diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, 4,4'-diphenylpropane diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate Aromatic diisocyanates such as naphthylene-1,4-diisocyanate, naphthylene-1,5-diisocyanate, 3,3′-dimethoxydiphenyl-4,4′-diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (hereinafter abbreviated as HDI) ), Aliphatic diisocyanates such as decamethylene diisocyanate and lysine diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylene diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated tetramethylxylene diisocyanate, Combined and its polymer, urethane modified, allophanate modified, urea modified, biuret modified, carbodiimide modified Body, uretonimine modified product, uretdione modified product, an isocyanurate modified product, and further mixtures of two or more thereof. In the present invention, in consideration of the weather resistance of the molded product, aliphatic and / or alicyclic diisocyanates are preferable, and HDI is particularly preferable.

  The ratio of the polymer polyol used to obtain the isocyanate group-containing prepolymer and the organic polyisocyanate is such that the molar ratio of the latter to the hydroxyl group of the former ([NCO] / [OH]) is 1.05. The ratio is preferably -5.0, more preferably 1.3-2.5.

  The monofunctional active hydrogen group-containing compound used for adjusting the molecular weight of the powdered thermoplastic polyurethane resin (A1) is an active hydrogen group-containing compound having an active hydrogen group and a hydrocarbon group having 4 to 12 carbon atoms. is there.

Examples of the “active hydrogen group” of the monofunctional active hydrogen group-containing compound include a hydroxyl group (—OH), an imino group (═NH), and an amino group (—NH ₂ ).

Examples of the “hydrocarbon group having 4 to 12 carbon atoms” possessed by the monofunctional active hydrogen group-containing compound include alkyl groups and alkenyl groups.
The carbon number of the “hydrocarbon group” of the monofunctional active hydrogen group-containing compound is 4 to 12, preferably 4 to 11, and more preferably 4 to 9.
When an active hydrogen group-containing compound having less than 4 carbon atoms is used, the prepolymerization reaction becomes incomplete because the boiling point is low and the compound tends to evaporate out of the reaction system, and the molecular weight of the resulting resin cannot be controlled. On the other hand, when an active hydrogen group-containing compound having more than 12 carbon atoms is used, blooming occurs in a molded product of the resulting resin.

  Specific examples of the monofunctional active hydrogen group-containing compound include di-n-butylamine, di-isobutylamine, di-t-butylamine, di-n-hexylamine, di-cyclohexylamine, di-n-octylamine, Dialkylamines (secondary amines) such as di-2-ethylhexylamine, di-n-nonylamine, di-dodecylamine; dialkenylamines such as di-allylamine; alkylamines (primary amine) such as dodecylamine; Examples include monools such as n-butanol, isobutanol, n-octanol, 2-ethylhexanol, n-nonanol, n-decanol, lauryl alcohol, and cyclohexanol. These may be used alone or in combination of two or more. Can be used. Of these, dialkylamine is preferred.

The bifunctional active hydrogen group-containing compound used for obtaining the isocyanate group-terminated prepolymer (II) is a bifunctional active hydrogen group-containing compound having a number average molecular weight of less than 500.
Specific examples of the bifunctional active hydrogen group-containing compound include compounds exemplified as low molecular polyols used to obtain polyester polyols which are high molecular polyols, and these may be used alone or in combination of two or more. Can be used. Of these, 1,4-BD and 1,6-HD are preferred.

  The water used for obtaining the powdery thermoplastic polyurethane resin (A1) used in the present invention can be used as a chain extender for the isocyanate group-terminated prepolymer and can also serve as a dispersion medium.

Although a powdery thermoplastic polyurethane resin (A1) is not specifically limited as a manufacturing method, For example, the following method can be illustrated.
(1) A method for obtaining a powder of a powdered thermoplastic polyurethane resin (A1) by freeze-grinding a thermoplastic polyurethane resin obtained by bulk polymerization by a known method (2) A non-aqueous system that does not dissolve an isocyanate group-terminated prepolymer (3) A method for obtaining a powdery thermoplastic polyurethane resin (A1) by separating and drying a polyurethane resin obtained by dispersing in a dispersion medium and reacting with water and extending the chain to obtain a powdery thermoplastic polyurethane resin (A1). The polyurethane resin obtained through the step of reacting the isocyanate group-terminated prepolymer with the remaining active hydrogen group of the isocyanate group-terminated prepolymer with water is separated and dried to obtain a powdered thermoplastic polyurethane resin (A1) Among these, a resin having a spherical shape and good powder flowability is obtained (2). The method of Beauty (3) is preferable.

In the method (2), a method in which a polymer polyol is dispersed in a non-aqueous dispersion medium and then an organic polyisocyanate is added and reacted to obtain an isocyanate group-terminated prepolymer. Further, when dispersing the polymer polyol in the non-aqueous dispersion medium, it is preferable to use a dispersant described later.
Examples of the dispersant include a polymer obtained by radical polymerization of an acrylic acid ester, a methacrylic acid ester, a styrene derivative, acrylonitrile, or the like to a polyester having an ethylenic double bond.

  At this stage of dispersing the polymer polyol in the non-aqueous dispersion medium, the volume average particle diameter of the final powdered thermoplastic polyurethane resin (A1) is adjusted by appropriately adjusting the dispersion temperature and dispersion time. Can do.

The powdered thermoplastic polyurethane resin (A1) used in the present invention has a number average molecular weight (Mn) of a component related to the main peak having the maximum peak area in a chart obtained by measuring this by gel permeation chromatography (GPC). Is preferably 18,000 to 50,000, and more preferably 20,000 to 45,000.
When the number average molecular weight (Mn) is too small, sufficient mechanical properties and durability cannot be imparted to the finally obtained molded product. On the other hand, when the number average molecular weight (Mn) is excessive, suitable melt moldability cannot be exhibited.

  An additive can be added to the powdered thermoplastic polyurethane resin (A1) used in the present invention as necessary. Such additives include pigments / dyes, antioxidants, UV absorbers, plasticizers, antiblocking agents, radical polymerization initiators, coupling agents, flame retardants, inorganic and organic fillers, lubricants, antistatic agents, and crosslinks. An agent etc. can be mentioned.

  As an example of a powdered colored pigment, Sumika Color's carbon black dispersion pigment “PV-817”, titanium oxide dispersion pigment “PV-7A1301”, titanium oxide dispersion pigment “PV-346”, and the like are suitable. What was mixed beforehand according to the target color tone can also be used. The addition amount of the pigment is usually 5% or less, preferably 0.5 to 2.0% with respect to the powdered thermoplastic polyurethane resin.

  Further, in order to improve the adhesion of (A2) to (A1) and the powdered colored pigment, and (A1) to prevent the powdered colored pigment from falling off from the surface, an auxiliary agent may be used in combination. Examples of auxiliary agents include plasticizers, silane coupling agents, silicone oils, etc., preferably plasticizers containing ester groups in the molecule, particularly preferred are ether-based active hydrogen compounds and mono- or di-acids. Alternatively, it is an ether ester plasticizer having an ether group and an ester group in the molecule by an esterification reaction with tricarboxylic acid.

The powdery pyrolytic foaming agent (A2) used in the present invention has a volume average particle size of 20 μm or less, preferably 10 μm or less, particularly preferably 6 μm or less. When the volume average particle size of (A2) is too large, the expansion ratio decreases due to non-uniform foaming, the cells become non-uniform, voids are generated, and the tactile sensation is deteriorated. Decreases.
Here, the “volume average particle size” refers to a cumulative percent value of 50% in a particle size distribution (volume distribution) curve measured by a laser diffraction particle size analyzer.

  When the powdered pyrolytic foaming agent (A2) is an organic pyrolytic foaming agent (A2-1), a powdered thermoplastic polyurethane resin (A1), an organic pyrolytic foaming agent (A2-1), Is a proportion of 0.2 to 1.0% by mass, preferably 0.4 to 0.8% by mass, and more preferably 0.4 to 0.8% by mass with respect to the powdered thermoplastic polyurethane resin (A1). Compounded at a ratio of 0.7% by mass.

  When the powdered pyrolytic foaming agent (A2) is an inorganic thermal decomposable foaming agent (A2-2), a powdered thermoplastic polyurethane resin (A1) and an inorganic pyrolytic foaming agent (A2-2) The compounding ratio is 1.0 to 4.5% by mass with respect to the powdered thermoplastic polyurethane resin (A1), preferably compounded at a rate of 2.0 to 4.0% by mass. is there.

  When the amount of the powdered pyrolytic foaming agent (A2) is too small, the foaming ratio is lowered, so that the weight of the molded product is insufficient, the feel of the molded product is deteriorated (feels terrible), etc. The problem is likely to occur. If there are too many powdered pyrolytic foaming agents (A2), the cells will become non-uniform and voids will occur, resulting in poor external appearance and feel, and poor mechanical properties and durability. Is prone to occur. Further, at the time of molding, the deformation of the thermoplastic polyurethane resin cannot completely catch the generated gas, and at a certain point, the expansion ratio reaches a peak, and the effect of increasing the foaming agent is less likely to appear.

Here, examples of the organic pyrolytic foaming agent (A2-1) include the following.
Azo compounds: azodicarbonamide (hereinafter abbreviated as ADCA), 2,2'-azobisisobutyronitrile, azohexahydrobenzonitrile, diazoaminobenzene, etc. Nitroso compounds: N, N'-dinitrosopentamethylenetetramine Sulfohydrazine compounds such as N, N'-dinitroso-N, N'-dimethylterephthalamide: benzenesulfonyl hydrazide, benzene-1,3-disulfonyl hydrazide, diphenylsulfone-3,3'-disulfonylhydrazide, 4, 4'-oxybis (benzenesulfonylhydrazide) (hereinafter abbreviated as OBSH), etc.

Examples of the inorganic pyrolytic foaming agent (A2-2) include those shown below.
sodium hydrogen carbonate

  These can be used alone or in admixture of two or more. The organic pyrolyzable foaming agent (A2-1) and the inorganic pyrolyzable foaming agent (A2-2) preferred in the present invention have a decomposition gas release temperature of 120 to 250 ° C. in consideration of the temperature during slush molding. Especially, what is 180-210 degreeC is preferable. Further, considering the influence on the environment, one selected from ADCA and sodium bicarbonate is preferable, and ADCA is more preferable.

  The production method of the foamable powdered thermoplastic polyurethane resin composition (A) includes (a) compounding the powders, (b) (A2) at any stage in the production of the powdered thermoplastic polyurethane resin. Although the method of mix | blending etc. is mentioned, since the method of (b) may give an excess heat history to a powdery thermal decomposition-type foaming agent (A2), the method of (a) is preferable.

Specifically, the powdered thermoplastic polyurethane resin (A1) is charged into a high-speed stirring and mixing apparatus such as a Henschel mixer or a super mixer, and then the powdered pyrolytic foaming agent (A2) is added. (A) can be produced by stirring and mixing at 1,000 rpm to uniformly adhere (A2) to the particle surface of the powdered thermoplastic polyurethane resin (A1).
Here, when it is necessary to color the foamable powdered thermoplastic polyurethane resin composition (A), 0.5 to 2.0% of the powdered color pigment is added to (A1), and the same as described above. It is also possible to obtain a foamable powdery thermoplastic polyurethane resin composition (A) as a colored powder by stirring and mixing (A1), (A2) and the powdered colored pigment using .
Alternatively, a powdered color pigment is blended at an arbitrary stage for producing a powdered thermoplastic polyurethane resin to obtain a colored powdered thermoplastic polyurethane resin, and then (A2) is added and stirred at 200 to 4,000 rpm. Then, (A2) can be uniformly adhered to the particle surface of the colored powdered thermoplastic polyurethane resin to produce (A).

  The sheet-like polyurethane resin molded product having a two-layer structure of the present invention will be described. The sheet-like polyurethane resin molded product having a two-layer structure of the present invention includes a foamed layer (a) obtained by molding a foamable powdered thermoplastic polyurethane resin composition (A), and a non-foamable powdered thermoplastic polyurethane resin composition. The non-foamed layer (b) molded from (B) has a fused structure. In (B), additives such as pigments, dyes, catalysts, light stabilizers, plasticizers, fillers, antioxidants, flame retardants and the like may be blended.

The thickness of the sheet-like polyurethane resin molded product having a two-layer structure is 0.3 to 2.5 mm, preferably 0.5 to 2.0 mm. Here, the “thickness” is a thickness measured at a predetermined number of locations of the molded product, and the average value is defined as “thickness”.
Moreover, the ratio of the thickness of the foam layer (a) to the thickness of the entire molded product is 0.4 to 0.92, preferably 0.50 to 0.90, and more preferably 0.6 to 0.88. is there. When the ratio of the foamed layer (a) is too small, weight reduction as a whole molded article is not achieved, and it is difficult to have a soft touch. If it is too large, voids appear on the surface and the appearance tends to be poor, the design properties are lowered, and the mechanical properties and durability of the molded product as a whole tend to be insufficient.

The specific gravity of the sheet-form polyurethane resin molding having a two-layer structure is at 0.87 g / cm ³ or less, preferably 0.81 g / cm ³ or less, further preferably 0.75 g / cm ³ or less. If the specific gravity is too large, weight reduction cannot be achieved.

The surface hardness (H _A ) of the sheet-like polyurethane resin molding having a two-layer structure is 65 ° or less, preferably 60 ° or less, and more preferably 57 ° or less. If the surface hardness is too high, a soft tactile sensation cannot be obtained.

  The powdered thermoplastic polyurethane resin (A1) in the foamable powdered thermoplastic polyurethane resin composition (A) and the powdered thermoplastic polyurethane resin in the non-foamable powdered thermoplastic polyurethane resin composition (B) are the same. Or different. In view of the adhesion at the interface between the (a) layer and the (b) layer, the raw material polymer polyol of the powdered thermoplastic polyurethane resin (A1) in (A) and the powdered thermoplastic polyurethane resin in (B) is of the same type. It is preferable that

  The manufacturing method of the sheet-like polyurethane resin molding which has a two-layer structure of this invention is demonstrated. The method for producing a sheet-like polyurethane resin molded product having a two-layer structure according to the present invention is obtained by melting a non-foamable powdered thermoplastic polyurethane resin composition (B) on the mold surface and then foaming the powdery polyurethane resin composition thereon. The thermoplastic polyurethane resin composition (A) is laminated, the powder resin is melted and foamed by heating, and the non-foamed layer and the foamed layer are integrally formed.

Specifically, there are the following two production methods.
Method A: A method for indirectly heating a mold, characterized by passing through the following three steps.
First step: A non-foamable powdered thermoplastic polyurethane resin composition (B) is charged into a mold preheated to 200 ° C. to 300 ° C., and the mold is inverted to remove excess powder material. A process of attaching and melting (B) with a uniform thickness on the mold surface. Second process: The foamable powdered thermoplastic polyurethane resin composition (A) is charged while (B) is attached to the mold. Inverting the mold to remove excess powder material and depositing (A) on the layer (B) with a predetermined thickness Third step: (A) layer in a heating oven at 200 to 400 ° C. And (B) the layered and adhered mold is placed for 30 to 120 seconds to complete the melting and foaming of the powdered resin, and then taken out of the heating oven and cooled to mold, and then the molded product is demolded. Process

Method B: A manufacturing method in which the mold self-heats, characterized by passing through the following three steps.
First step: A non-foamable powdered thermoplastic polyurethane resin composition (B) is charged into a mold preheated to 200 ° C. to 300 ° C., and the mold is inverted to remove excess powder material. A process of attaching and melting (B) with a uniform thickness on the mold surface. Second process: The foamable powdered thermoplastic polyurethane resin composition (A) is charged while (B) is attached to the mold. The process of inverting the mold to remove excess powder material and depositing (A) on the layer (B) with a predetermined thickness Third process: (A) layer and (B) layer are laminated and adhered The mold is self-heated at 200 ° C. to 300 ° C. for 30 to 120 seconds to complete the melting and foaming of the powder resin, and then the mold is cooled and then the molded product is demolded

  Examples of the self-heating system of the mold in the method B include a system in which a heating medium is flowed through a jacket attached to the outer surface of the mold and a system in which an electric heating wire is installed and energized to generate heat.

In both the A method and the B method, preferred holding times in each step (the time until the powder resin is charged in a mold and inverted to remove excess powder resin) and the heating time in the third step are as follows.
First step: 1 to 5 seconds is preferable.
Second step: 4 to 15 seconds is preferable.
Third step: 30 to 120 seconds are preferable.
By adjusting each holding time, the thickness of the molded product and the thickness ratio of each layer can be adjusted.

  The sheet-like polyurethane resin molded product having a two-layer structure of the foamed layer and the non-foamed layer thus obtained has a soft tactile sensation, is excellent in abrasion resistance, mechanical properties, etc. Cost reduction is realized. The sheet-like polyurethane resin molding obtained by the present invention is optimal for the skin of automobile interior materials (instrument panels, console boxes, armrests, etc.).

Examples of the present invention will be described below, but the present invention is not limited thereto.
[Preparation Example 1 (Preparation of Dispersant Solution)]
A reactor having a capacity of 2 L equipped with a stirrer, a thermometer, a distillation column and a nitrogen gas introduction tube was charged with 762 g of adipic acid, 49 g of maleic anhydride and 386 g of ethylene glycol, and at 150 ° C. and normal pressure while flowing nitrogen gas. The esterification reaction was carried out by stirring under the conditions of
When condensed water is no longer observed, add 0.1 g of tetrabutyl titanate, gradually reduce the pressure in the reaction system to 0.07 kPa, and gradually raise the temperature to 190 ° C. to continue the reaction. A polyester diol was obtained. The number average molecular weight of the obtained polyester diol was 2,000, and the iodine value was 12.7 gI / 100 g.
Subsequently, 74 g of the polyester diol and 150 g of butyl acetate were charged into a 500 mL reactor equipped with a stirrer, a thermometer, a distillation column and a nitrogen gas introduction tube, and the temperature was raised to 110 ° C. while flowing nitrogen gas. And stirred. Thereafter, a dissolved mixture of 75 g of 2-ethylhexyl methacrylate and 1 g of benzoyl peroxide was dropped from the dropping funnel over 1 hour. After completion of the dropping, the temperature was raised to 130 ° C. and the reaction was further continued for 2 hours to obtain a dispersant solution having a solid content of 50%. Hereinafter, this is referred to as “dispersant solution (1)”.

[Preparation Example 2 (Preparation of Dispersant Solution)]
A reactor having a capacity of 2 L equipped with a stirrer, a thermometer, a distillation column and a nitrogen gas introduction tube was charged with 565 g of adipic acid and 575 g of 3-methylpentanediol, and under conditions of 150 ° C. and normal pressure while flowing nitrogen gas And a polyester diol having a number average molecular weight of 1,000 was synthesized.
Next, 100 g of the polyester diol and 150 g of diisononyl adipate were charged into a 1,000 mL reactor equipped with a stirrer, thermometer, distillation column and nitrogen gas inlet tube, and the temperature was raised to 80 ° C. while flowing nitrogen gas. And stirred. To this, 42 g of hexamethylene diisocyanate was added and reacted at 80 ° C. for 2 hours to prepare an isocyanate group-containing prepolymer. An additional 200 g of polyvinyl alcohol having a number average molecular weight of 1,000 was added thereto and further reacted at 80 ° C. for 2 hours to obtain a dispersion stabilizer solution having a solid content of about 70%. Hereinafter, this is referred to as “dispersant solution (2)”.

[Preparation Examples 3 to 17 (Preparation of powdered thermoplastic polyurethane resins “A1-1” to “A1-14” and “A1-16”)]
To a reactor having a capacity of 3 L equipped with a stirrer, a thermometer, a cooler and a nitrogen gas introduction tube, 282.6 g of a polyester diol having a number average molecular weight of 2,600 obtained from 1,4-BD, ethylene glycol and adipic acid 201.8 g of a polyester diol having a number average molecular weight of 1,000 obtained from 1,4-BD and adipic acid, and a polyester diol having a number average molecular weight of 1,500 obtained from 1,6-HD and isophthalic acid322. After uniformly mixing 9 g at 80 to 100 ° C., 24.2 g of the dispersant solution (1) and 818.2 g of isooctane “Kyowasol C-800” (Kyowa Hakko Chemical Co., Ltd.) as a non-aqueous dispersion medium And the polymer polyol is dispersed in isooctane by stirring at 75 to 98 ° C. for 30 to 150 minutes. A dispersion was prepared.
To the above dispersion, 159.2 g of HDI as an organic polyisocyanate and 0.005 g of a bismuth catalyst “Neostan U-600” (manufactured by Nitto Kasei Co., Ltd.) are added, and HDI is added at 90 to 95 ° C. over 3 hours. By reacting with the polymer polyol, a dispersion of the isocyanate group-terminated prepolymer (I) was prepared.
In the isocyanate group-terminated prepolymer dispersion liquid (I), 20.3 g of di-2-ethylhexylamine, which is a monofunctional active hydrogen group-containing compound, and 1,6-HD7. 5 g was added and reacted with the isocyanate group-terminated prepolymer (I) at 80 to 90 ° C. to prepare a dispersion of the isocyanate group-terminated prepolymer (II).
50.7 g of water (corresponding to 10 equivalents of isocyanate group (calculated value) of isocyanate group-terminated prepolymer (II)) was added to the above-mentioned isocyanate group-terminated prepolymer (II) dispersion, and isocyanate group-terminated prepolymer A polyurethane resin dispersion was prepared by subjecting (II) and water to a chain extension reaction at 65 to 70 ° C. until the isocyanate groups were consumed.
The solid content (polyurethane resin) was filtered off from the polyurethane resin dispersion, and the following additives (1) to (4) were added and dried. Powdered thermoplastic polyurethane resin (A1) was prepared by adding 3.0 g of Chemical Co., Ltd. As shown in Tables 1 and 2, “A1-1” to “A1-14” and “A1-16” were obtained by appropriately changing the dispersion conditions. The obtained resin particles were spherical (short / long = 1.0), the molecular weight did not change even when the particle size was changed, and the number average molecular weight was 29,000 in all (Table 1, 2).
〔Additive〕
(1) Antioxidant: “Irganox 245” (manufactured by Ciba Specialty Chemicals), addition amount = 2.0 g.
(2) Ultraviolet absorber: “Tinuvin 213” (manufactured by Ciba Specialty Chemicals), addition amount = 2.0 g.
(3) Light stabilizer: “Tinuvin 765” (manufactured by Ciba Specialty Chemicals), addition amount = 2.0 g.
(4) Antiblocking agent: “SH200-300CV” (manufactured by Toray Dow Corning), addition amount = 1.5 g.

[Preparation Example 18 (Preparation of powdered thermoplastic polyurethane resin “A1-15”)
293.2 kg of a polyester diol having a number average molecular weight of 2,600 obtained from 1,4-BD, ethylene glycol and adipic acid, and a polyester diol having a number average molecular weight of 1,000 obtained from 1,4-BD and adipic acid 209.4 kg and 335.1 kg of a polyester diol having a number average molecular weight of 1,500 obtained from 1,6-HD and isophthalic acid are mixed with 24.6 kg of 1,4-BD to obtain a uniform glycol component. did. This glycol component and HDI were mixed and supplied from a hopper of a twin-screw extruder adjusted to a temperature of about 190 ° C. at a flow rate ratio of 100: 17.5, and resinification was performed simultaneously with kneading to obtain a polyurethane resin. .
The same additive as that used in Preparation Examples 3 to 17 was added to 100 parts of the polyurethane resin obtained by applying the polyurethane resin obtained in the above step to a pelletizer and pelletized, and the amount of the antioxidant was 0.25. Part, 0.15 part of UV absorber, 0.15 part of light stabilizer, 0.25 part of internal mold release agent, and supplied from a hopper of a twin screw extruder whose temperature is adjusted to about 200 ° C. Kneading was performed to obtain a polyurethane resin.
The polyurethane resin to which the additive was added as described above was cooled to about −150 ° C. with liquid nitrogen, and pulverized with an impact pulverizer. In order to impart fluidity to this, 0.4 g of the dusting agent “MP-1451” was added to 100 g of the resin, and the mixture was stirred and mixed so as to uniformly adhere to the surface of the polyurethane resin. Thereafter, particles of 700 μm or more were classified and removed to obtain a powdered thermoplastic polyurethane resin composition “A1-15”.
The shape of the obtained resin composition was indefinite, the volume average particle size was 300 μm, and the number average molecular weight was 30,000 (see Table 2).

[Preparation Example 19 (Preparation of powdered thermoplastic polyurethane resin “A1-B”)]
To a reactor having a capacity of 3 L equipped with a stirrer, a thermometer, a cooler and a nitrogen gas introduction tube, 245.5 g of a polyester diol having a number average molecular weight of 2,600 obtained from 1,4-BD, ethylene glycol and adipic acid 163.7 g of a polyester diol having a number average molecular weight of 1,000 obtained from 1,4-BD and adipic acid, and a polyester diol having a number average molecular weight of 1,500 obtained from 1,6-HD and isophthalic acid 409.g. 1 g was mixed at 90 ° C.
Next, the mixture is cooled to 65 ° C., and 8.8 g of di-n-butylamine which is a monofunctional active hydrogen group-containing compound and 6.5 g of 1,4-BD which is a bifunctional active hydrogen group-containing compound are added. Further mixed, 160.7 g of HDI and 0.05 g of bismuth catalyst “Neostan U-600” (manufactured by Nitto Kasei Co., Ltd.) were added, first at 65 ° C. for 15 minutes and then at 80-90 ° C. for 3 hours. By reacting, an isocyanate group-terminated prepolymer (III) was obtained.
After the above isocyanate group-containing prepolymer (III) is cooled to 60 ° C., 199 g of MEK and 42.6 g of dispersion stabilizer (2) are added and mixed uniformly to prepare an isocyanate group-containing prepolymer / dispersant mixture. did.
The amount of MEK is an amount corresponding to 20% with respect to the obtained isocyanate group-containing prepolymer. Further, the amount of the dispersion stabilizer solution (2) is an amount corresponding to 3.0% with respect to the obtained isocyanate group-containing prepolymer.
Next, the total amount of the blend was adjusted to 60 ° C., and heated in 60 ° C. hot water (2,353 g) for 2 minutes using a homomixer (mechanical forced disperser) manufactured by Primix Co., Ltd. at a rotation speed of 8,000 rpm. Mix and disperse.
This mixed dispersion was transferred to a reaction vessel equipped with a thermometer, a stirrer and a nitrogen blowing tube, and reacted at 60 ° C. for 10 hours while stirring.
The solid content (polyurethane resin) is filtered off from the polyurethane resin dispersion, and the additives (1) to (4) shown below are added thereto and dried. Then, the dusting agent “MP-1451” ( Powdered thermoplastic polyurethane resin “A1-B” was prepared by adding 3.0 g of Sokenken Chemical Co., Ltd.). The obtained resin particles were spherical (short / long = 1.0), the volume average particle size was 140 μm, and the number average molecular weight was 32,000 (see Table 2).
〔Additive〕
(1) Antioxidant: “Irganox 245” (manufactured by Ciba Specialty Chemicals), addition amount = 2.0 g.
(2) Ultraviolet absorber: “Tinuvin 213” (manufactured by Ciba Specialty Chemicals), addition amount = 2.0 g.
(3) Light stabilizer: “Tinuvin 765” (manufactured by Ciba Specialty Chemicals), addition amount = 2.0 g.
(4) Internal mold release agent: “SH200-100,000 cs” (manufactured by Toray Dow Corning Co., Ltd.), addition amount = 2.0 g.

[Examples 1 to 10, Comparative Examples 1 to 6 (Preparation of foamable powdered thermoplastic polyurethane resin composition (A)) 1]
1,500 g of thermoplastic polyurethane resins “A1-1” to “A1-16” having different powder flowability are respectively charged in a 9 L Henschel mixer, and volume as a powdery organic pyrolytic foaming agent (A2-1). 0.7% (10.5 g) of azodicarbonamide (ADCA) powder “A2-1-2” having an average particle diameter of 6 μm was added. Next, 0.8% (12 g) of the following color pigment “D-1” was added, and each mixture was stirred and mixed at 1,000 rpm for 40 seconds to prepare a foamable powdered thermoplastic polyurethane resin composition (A). Each was designated as resins “PU-1” to “PU-16” (see Tables 3 and 4 for mass ratio and properties).

[Coloring pigment D-1]
667 g of carbon black dispersed pigment “PV-817” manufactured by Sumika Color Co., Ltd. and 333 g of titanium oxide dispersed pigment “PV-7A1301” manufactured by the same company were mixed using a ribbon mixer exclusively for powders.

[Examples 11 to 13, Comparative Examples 7 to 9 (adjustment of foamable powdered thermoplastic polyurethane resin composition (A)): Part 2]
1,500 g of the thermoplastic polyurethane resin “A1-8” was charged into a 9 L Henschel mixer, and the powdery organic pyrolytic foaming agent (A2-1) was used as an ADCA powder “A2-1-2” having a volume average particle size of 6 μm. ”Was added by changing the addition amount in the range of 0% (0 g) to 1.3% (19.5 g). Next, 0.8% (12 g) of the above-mentioned colored pigment “D-1” was added, and each mixture was stirred and mixed at 1,000 rpm for 40 seconds to prepare a foamable powdered thermoplastic polyurethane resin composition (A). Each was made into resin "PU-17"-"PU-22" (refer Table 5 for mass ratio and a property).

[Examples 14 to 17, Comparative Examples 10 and 11 (adjustment of foamable powdered thermoplastic polyurethane resin composition (A)): Part 3]
1,500 g of the thermoplastic polyurethane resin “A1-8” was charged into a 9 L Henschel mixer, and sodium hydrogen carbonate (NaHCO ₃ ) powder having a volume average particle size of 5 μm as a powdery inorganic pyrolytic foaming agent (A2-2). “A2-2-1” was added by changing the addition amount in the range of 0.7% (10.5 g) to 5.0% (75.0 g). Next, 0.8% (12 g) of the above-mentioned colored pigment “D-1” was added, and each mixture was stirred and mixed at 1,000 rpm for 40 seconds to prepare a foamable powdered thermoplastic polyurethane resin composition (A). Each was designated as resins “PU-23” to “PU-28” (see Table 6 for mass ratio and properties).

[Examples 18 and 19 and Comparative Example 12 (adjustment of foamable powdered thermoplastic polyurethane resin composition (A)): Part 4]
1,500 g of the thermoplastic polyurethane resin “A1-8” is charged into a 9 L Henschel mixer, and the powdery organic pyrolytic foaming agent (A2-1) is an ADCA powder “4 μm with a volume average particle size of 4 μm, 20 μm, and 25 μm. : A2-1-1, 20 μm: A2-1-3, 25 μm: A2-1-4 ”were added by 0.7% (10.5 g), respectively. Next, 0.8% (12 g) of the above-mentioned color pigment “D-1” was added, and each mixture was stirred and mixed at 1,000 rpm for 40 seconds to prepare a foamable powdered thermoplastic polyurethane resin composition (A). Each was made into resin "PU-29"-"PU-31" (refer Table 7 for mass ratio and a property).

[Reference Examples 1 and 2 (Preparation of non-foamable powdered thermoplastic polyurethane resin composition (B))]
1,500 g of thermoplastic polyurethane resins “A1-8” and “A1-B” were respectively charged in a Henschel mixer having a capacity of 9 L, and then 0.8% (12 g) of the aforementioned color pigment “D-1” was added, The powdered thermoplastic polyurethane resin composition (B) was prepared by stirring and mixing at 1,000 rpm for 30 seconds to obtain resins “PU-B1” and “PU-B2” (see Table 3 for mass ratio and properties).

Example 20 (Production of sheet-like polyurethane resin molding having a two-layer structure) 1]
In a mold heated to 250 ° C., “PU-B1” as a non-foaming plastic polyurethane resin composition (B) is charged and held for 2 seconds, the mold is inverted to remove excess powder material, A foam layer was formed. Subsequently, “PU-3” is charged as the foamable thermoplastic polyurethane resin composition (A) containing the organic pyrolytic foaming agent (A2-1) in the same mold with the non-foamed layer attached. Held for 4 seconds, the mold was inverted to remove excess powder material and form a foamed layer. This mold is placed in a heating furnace at 300 ° C. and heated for 30 seconds, and then the mold taken out from the heating furnace is cooled and demolded so that the non-foamed layer and the foamed layer are integrated. The sheet-like polyurethane resin molding was obtained.
In this example, the powdered thermoplastic polyurethane resin (A1) used has a volume average particle size of 110 μm, the content of particles less than 100 μm is 40% by mass, the content of particles less than 30 μm is 5% by mass, The content of particles less than 20 μm is 2% by mass. The bulk specific gravity as (A) is 0.60 g / cm ³ , the flow time is 20 seconds, the angle of repose is 35 °, and the blocking resistance is 51%. When the thickness was measured for a predetermined number of places of the obtained molded product and the average value thereof was calculated, the total thickness was 1.2 mm, the non-foamed layer thickness was 0.2 mm, and the foamed layer thickness was 1.0 mm. The ratio was 0.83, and the molded product had a uniform thickness. Moreover, the characteristic described in Table 8 was confirmed. The true specific gravity of the molded product was 0.65 g / cm ³ , and the hardness was HA = 51 degrees. These are equivalent to 44% weight reduction and 29 point hardness reduction, compared to the molding of Comparative Example-29 described later, which is composed only of “PU-B2”. It became.

[Examples 21 to 29 (production of a sheet-like polyurethane resin molded product having a two-layer structure) 2]
“PU-B1” for the non-foamed layer, “PU-4”, “PU-5”, “PU-7”, “PU-8”, “PU-10”, “PU-11” for the foamed layer, And “PU-13” to “PU-15” were used, and in the step of forming the foamed layer of the molding method of Example 20, the holding time was adjusted to equalize the thickness of each molded product. Other molding steps were the same as in Example 20, and a sheet-like polyurethane resin molded product having a two-layer structure was obtained.
In this example, the powdered thermoplastic polyurethane resin (A1) used has a volume average particle size of 110 to 300 μm, the content of particles less than 100 μm is 40% by mass or less, and the content of particles less than 30 μm is 5 The content of particles of less than 20% by mass and less than 20 μm is 2% by mass or less. The obtained molded product showed the good characteristics described in Tables 8 and 9, and became a molded product having a uniform thickness. Moreover, the weight was reduced as compared with the molded product of “PU-B2” alone, and the molded product had a good tactile sensation.

[Comparative Examples 13 and 18 (Production of a sheet-like polyurethane resin molded product having a two-layer structure) 3]
In the step of forming the foamed layer of the molding method of Example 20 using “PU-B1” for the non-foamed layer and “PU-1” or “PU-16” for the foamed layer, respectively, The holding time was adjusted to align the thickness with Examples 20-29. Other molding steps were the same as in Example 20.
Comparative Examples 13 and 18 are comparative examples using powdered thermoplastic polyurethane resin (A1) having a volume average particle size outside the range of 110 to 300 μm. In the case of Comparative Example 13, “PU-1” has a low volume average particle size and thus poor powder flowability, and “PU-1” can be laminated with a uniform thickness on the formed non-foamed layer. In Comparative Example 13, it was difficult to obtain a molded product. On the other hand, for Comparative Example 18 using “PU-16” having a large volume average particle size of 350 μm, a sheet-like polyurethane resin molded product having a two-layer structure was obtained, but the mechanical properties were deteriorated due to poor melting. Was confirmed.

[Comparative Examples 14 to 17 (Production of sheet-like polyurethane resin molding having a two-layer structure) 4]
Foaming of the molding method of Example 20 using “PU-B1” for the non-foamed layer and “PU-2”, “PU-6”, “PU-9” or “PU-12” for the foamed layer. In the step of forming the layer, the holding time was adjusted in order to make the thickness of each molded product uniform in Examples 20-29. Other molding steps were the same as in Example 20.
In Comparative Examples 14 to 17, the content of particles less than 100 μm in the powdered thermoplastic polyurethane resin (A1) is 40% by mass or less, the content of particles less than 30 μm is 5% by mass or less, and less than 20 μm. It is a comparative example using what does not enter into the range whose content is 2 mass% or less. The obtained molded product exhibited the characteristics described in Tables 8 and 9, had poor powder flowability, and it was difficult to mold the foamed layer with a uniform thickness.

[Examples 30 to 33 (Production of sheet-like polyurethane resin molding having a two-layer structure) 5]
In the step of forming the foamed layer of the molding method of Example 20 using “PU-B2” for the non-foamed layer and “PU-19” to “PU-21” for the foamed layer, respectively, In order to adjust the thickness to that of Example 20, the holding time was adjusted. Other molding steps were the same as in Example 20, and a sheet-like polyurethane resin molded product having a two-layer structure was obtained.
In this example, the addition amount of the organic pyrolytic foaming agent (A2-1) is 0.2 to 1.0% by mass. The obtained molded product showed the favorable characteristics described in Table 10, was lighter than the molded product of “PU-B2” alone, and formed a molded product with good tactile sensation.

[Comparative Examples 19 to 21 (Manufacture of a sheet-like polyurethane resin molding having a two-layer structure) 6]
Using “PU-B2” for the non-foamed layer and “PU-17”, “PU-18” or “PU-22” for the foamed layer, the foamed layer of the molding methods of Examples 30 to 33 is formed. In the process, the holding time was adjusted in order to adjust the thickness of each molded product. Other molding steps were the same as in Examples 30 to 33, and a sheet-like polyurethane resin molded product having a two-layer structure was obtained.
Comparative Examples 19 to 21 are comparative examples when the amount of the organic pyrolytic foaming agent (A2-1) added is outside the range of 0.2 to 1.0 mass%. The obtained molded product showed the characteristics described in Table 10, Comparative Example 19 and Comparative Example 20 were not reduced in weight and insufficient in tactile sense, and Comparative Example 21 was confirmed to have a significant decrease in mechanical properties. It was.

[Comparative Examples 22 and 23 (Production of sheet-like polyurethane resin molding having a two-layer structure) 7]
Using “PU-19” or “PU-21” as the foam layer, the step of forming the non-foam layer in the molding methods of Examples 30 to 33 was omitted, and the process was performed from the step of forming the foam layer. The holding time was adjusted in order to make the thickness of each molded product the same as in Examples 30 to 33, and a sheet-like polyurethane resin molded product having a single layer structure was obtained.
In Comparative Examples 22 and 23, there was no non-foamed layer in the obtained molded product. These molded products exhibited the characteristics shown in Table 10, and it was confirmed that the appearance of the product surface was poor due to pinholes, and the mechanical characteristics and durability were significantly lowered.

[Examples 34 to 37 (Production of sheet-like polyurethane resin molding having a two-layer structure) 8]
In the step of forming the foamed layer of the molding method of Example 20, using “PU-B2” for the non-foamed layer and “PU-24” to “PU-27” for the foamed layer, respectively, In order to adjust the thickness to that of Example 20, the holding time was adjusted. Other molding steps were the same as in Example 20, and a sheet-like polyurethane resin molded product having a two-layer structure was obtained.
In this example, the amount of the inorganic pyrolytic foaming agent (A2-2) added is 1.0 to 4.5% by mass. The obtained molded product showed good characteristics described in Table 11, was lighter than the molded product using only “PU-B2”, and formed a molded product having a good tactile sensation.

[Comparative Examples 24 and 25 (Production of sheet-like polyurethane resin molded product having a two-layer structure) 9]
In the step of forming the foam layer of the molding method of Examples 34 to 37 using “PU-B2” for the non-foam layer and “PU-23” or “PU-28” for the foam layer, The holding time was adjusted to adjust the thickness of the object. Other molding steps were the same as in Examples 34 to 37, and a sheet-like polyurethane resin molded product having a two-layer structure was obtained.
Comparative Examples 24 and 25 are comparative examples in the case where the addition amount of the inorganic pyrolytic foaming agent (A2-2) is out of the range of 1.0 to 4.5% by mass. The obtained molded product exhibited the characteristics shown in Table 11. Comparative Example 24 was not reduced in weight and also had insufficient tactile sensation. In Comparative Example 25, a significant decrease in mechanical characteristics was confirmed.

[Examples 38 and 39 (Production of sheet-like polyurethane resin molded product having a two-layer structure) 10]
In a mold preheated to 250 ° C., “PU-B2” is charged as a non-foamable powdered thermoplastic polyurethane resin composition (B) and held for 2 seconds, and the mold is inverted to remove excess powder material. Removed to form a non-foamed layer. Subsequently, “PU-29” as a foamable powdery thermoplastic polyurethane resin composition (A) containing an organic pyrolytic foaming agent (A2-1) in the same mold with the non-foamed layer attached. Alternatively, “PU-30” was charged and held for a certain time (in order to make the thickness of the molded product uniform), and the mold was inverted to remove excess powder material to form a foam layer. The mold is heated for 30 seconds at 300 ° C. with self-heating, and then cooled and removed from the mold, thereby forming a sheet-like polyurethane resin molded article having a non-foamed layer and a foamed layer integrated. Got.
In this example, the particle size of the pyrolytic foaming agent ADCA used as (A2-1) is 4 to 20 μm. The obtained molded product exhibited good characteristics described in Table 12, was lighter than the molded product of Comparative Example 19 described above, and had a good tactile feel.

[Comparative Example 26 (Production of sheet-like polyurethane resin molded product having a two-layer structure) 11]
In the step of forming the foamed layer of the molding method of Examples 38 and 39 using “PU-B2” for the non-foamed layer and “PU-31” for the foamed layer, the thickness of the molded product was determined in Example 38, The holding time was adjusted to be 39. Other molding steps were the same as in Examples 38 and 39, and a sheet-like polyurethane resin molded product having a two-layer structure was obtained.
The comparative example 26 is a comparative example in which the particle size of the pyrolytic foaming agent ADCA used exceeds 25 μm and exceeds 20 μm which is the upper limit of the present invention. The obtained molded product exhibited the characteristics described in Table 12, and the cells became non-uniform compared to Example 39 using 20 μm ADCA, confirming the deterioration of the mechanical characteristics.

[Examples 40 to 42 (Production of sheet-like polyurethane resin molding having a two-layer structure) 12]
In order to change the thickness ratio between the non-foamed layer and the foamed layer of each molded product using “PU-B2” for the non-foamed layer and “PU-8” for the foamed layer, respectively, the molding method of Example 20 In the step of forming the non-foamed layer and the foamed layer, the holding time was adjusted. Other molding steps were the same as in Example 20, and a sheet-like polyurethane resin molded product having a two-layer structure was obtained.
In this example, the ratio of the thickness of the foam layer (a) to the thickness of the entire molded product is 0.50 to 0.92. The obtained molded product showed the favorable characteristics described in Table 13, was lighter than the molded product of Comparative Example 19 described above, and had a good tactile feel.

[Comparative Examples 27 to 28 (Production of sheet-like polyurethane resin molded product having a two-layer structure) 13]
By using “PU-B2” for the non-foamed layer and “PU-8” for the foamed layer, respectively, a sheet-like polyurethane resin molded product having a two-layer structure was obtained by the same molding method as in Examples 40 to 42. .
Comparative Examples 27 and 28 are comparative examples when the ratio of the thickness of the foam layer (a) to the thickness of the entire molded product is outside the range of 0.40 to 0.92. The obtained molded product exhibited the characteristics shown in Table 13, and in Comparative Example 27 in which the ratio of the thickness of the foamed layer (a) was as large as 0.96, it was confirmed that the appearance was poor and the mechanical characteristics and the durability were lowered. . The molded product of Comparative Example 28 having a small thickness ratio of the foamed layer (a) of 0.33 was insufficient in weight reduction and a soft tactile sensation was not obtained.

[Comparative Example 29 (Production of sheet-like polyurethane resin molded article) 14]
In a mold heated to 250 ° C., “PU-B2” as a powdered thermoplastic polyurethane resin composition (B) is charged and held for 16 seconds, and the mold is inverted to remove excess powder material. After the mold was placed in a 300 ° C. heating furnace and heated for 30 seconds, the mold taken out from the heating furnace was cooled and removed to obtain a sheet-shaped polyurethane resin molded article having a normal single layer structure. The obtained molded product exhibited the characteristics described in Table 13, and weight reduction was not achieved and a soft tactile sensation was not obtained.

Powder fluidity evaluation method Regarding powder fluidity, a loose bulk specific gravity of a powdered thermoplastic polyurethane resin composition using a bulk specific gravity measuring device (conforming to JIS-K6720) manufactured by Tsutsui Rika and a material of 100 cm ³ The time for flowing down the measuring device was measured.

Blocking test method About blocking resistance, the blocking rate was measured in the following procedure.
-About 150 g of a powdered thermoplastic polyurethane resin composition is weighed and put into a cylindrical steel can having a diameter of 50 mm and a height of 130 mm.
-A stainless steel weight having a diameter of 40 mm and a mass of 900 g is placed thereon and left in a constant temperature bath at 80 ° C for 24 hours (corresponding to a pressure of about 7 kPa).
-After removing the weight, the sample is allowed to stand in an atmosphere of 20 ° C for 2 hours, and the amount of the resin material that has passed through a sieve having an opening of 1 mm is weighed.
-The ratio of the amount of resin before the test and the amount that passed the sieve after the test is the pass rate.

Angle of repose evaluation method With respect to the angle of repose, a powdered thermoplastic polyurethane resin composition of 100 cm ³ was flowed out from above onto a horizontal surface using a bulk specific gravity measuring instrument (compliant with JIS-K6720) manufactured by Tsutsui Rika Co. It was deposited and the tilt angle of its surface was measured.

Uniformity of the thickness of the foamed layer The thickness was measured at predetermined locations on the obtained molded sheet, the difference between the maximum thickness and the minimum thickness was determined, and evaluated according to the following criteria.
“5”: Difference in thickness is less than 0.05 mm “4”: Difference in thickness is less than 0.05 to 0.10 mm “3”: Difference in thickness is less than 0.10 to 0.15 mm “2”: Difference in thickness Difference is less than 0.15 to 0.20 mm “1”: Difference in thickness is 0.20 mm or more

Cell uniformity The foamed cells of the obtained molded sheet were observed with a microscope and evaluated according to the following criteria.
“5”: cells are uniform “4”: cells are slightly non-uniform but not noticeable “3”: cells are slightly non-uniform but “2”: cells are slightly marked Non-uniform "1": Very remarkably non-uniform cell

Pinhole State The presence and extent of pinholes on the surface of the obtained molded sheet were observed with a microscope and evaluated according to the following criteria.
“5”: Pinholes are not recognized at all “4”: Pinholes are slightly noticeable but not noticeable “3”: Slightly but pinholes are clearly recognized “2”: Pinholes are present Slightly significant “1”: Very pinhole

Surface hardness Measured according to JIS K6253.

Abrasion resistance The obtained molded sheet was subjected to 100 reciprocating wear under the following conditions using a reciprocating plane abrasion tester, and the state of the molded sheet thereafter was visually observed and evaluated according to the following criteria.
Wear conditions ・ Reciprocating motion: 40 times / min ・ Friction: 30 mm × 12 mm
・ Load: 29.4N
・ Wear material: 5 white cotton kanakin No. 3 laminated Evaluation “5”: No damage at all “4”: Slightly damaged but not noticeable “3”: Slightly damaged Clearly recognized “2”: Slightly significant damage “1”: Very severely damaged

Mechanical properties The obtained molded sheet was subjected to a tensile test according to JIS K6251 and JIS K6252, and the tensile strength and elongation at break were measured.
Test conditions Sample: Dumbbell No. 1 type Tensile speed: 200 mm / min

Claims (12)

In the foamable powdered thermoplastic polyurethane resin composition (A) obtained by compounding the powdered thermoplastic polyurethane resin (A1) with the powdered pyrolytic foaming agent (A2),
The volume average particle diameter of the powdered thermoplastic polyurethane resin (A1) is 110 to 300 μm, the content of particles less than 100 μm is 40% by mass or less, and the content of particles less than 30 μm is 5% by mass or less, and The content of particles less than 20 μm is 2% by mass or less,
The volume average particle size of the powdered pyrolytic foaming agent (A2) is 20 μm or less,
A foamable powdered thermoplastic polyurethane resin composition (A) characterized by 2. The foamable powder according to claim 1, wherein the bulk specific gravity is 0.60 g / cm ³ or more and the time for 100 cm ³ (A) to flow down the funnel having an outlet inner diameter of 8 mm is 20 seconds or less. -Like thermoplastic polyurethane resin composition (A).   The repose angle is 35 ° or less, and the expandable powdery thermoplastic polyurethane resin composition (A) according to claim 1 or 2.   The foamable powdered thermoplastic polyurethane resin composition (A) according to any one of claims 1 to 3, wherein a pass rate when the blocking rate is measured is 50% or more.   The powdery pyrolyzable foaming agent (A2) is an organic pyrolyzable foaming agent (A2-1), and the organic pyrolyzable foaming agent (A2-1) is a powdery thermoplastic polyurethane resin (A1). The foamable powdery thermoplastic polyurethane resin according to any one of claims 1 to 4, which is compounded at a ratio of 0.2 to 1.0 mass% with respect to Composition (A).   The powdery pyrolyzable foaming agent (A2) is an inorganic pyrolyzable foaming agent (A2-2), and the inorganic pyrolyzable foaming agent (A2-2) is a powdery thermoplastic polyurethane resin (A1). The foamable powdered thermoplastic polyurethane resin according to any one of claims 1 to 4, which is compounded at a ratio of 1.0 to 4.5 mass% with respect to Composition (A).   A foam layer (a) obtained by molding the foamable powdered thermoplastic polyurethane resin composition (A) according to any one of claims 1 to 6, and a non-foamable powdery thermoplastic containing no foaming agent. A sheet-like polyurethane resin molded article having a two-layer structure of a non-foamed layer (b) obtained by molding the polyurethane resin composition (B).   The thickness ratio of the foam layer (a) is 0.4 to 0.92 with respect to the total thickness of the sheet-like polyurethane resin molded product having a two-layer structure composed of the foam layer (a) and the non-foam layer (b). A sheet-like polyurethane resin molded article having a two-layer structure according to claim 7. The non-foamable powdery thermoplastic polyurethane resin composition (B) is melted on the mold surface, and then the foamable powdery thermoplastic polyurethane resin according to any one of claims 1 to 6 is formed thereon. A method for producing a sheet-like polyurethane resin molding having a two-layer structure, comprising laminating the composition (A) and melting and foaming a powder resin by heating to integrally form a non-foamed layer and a foamed layer .   The non-foamable powdery thermoplastic polyurethane resin composition (B) is melted on the mold surface, and then the foamable powdery thermoplastic polyurethane resin according to any one of claims 1 to 6 is formed thereon. The composition (A) is laminated, and the powder resin is melted and foamed by heating, and the total thickness of the sheet-like polyurethane resin molded article having a two-layer structure comprising the non-foamed layer (b) and the foamed layer (a) And a non-foamed layer and a foamed layer are integrally formed so that the thickness ratio of the foamed layer (a) is 0.4 to 0.92. Manufacturing method. The method for producing a sheet-like polyurethane resin molded article having a two-layer structure according to claim 9 or 10, wherein the following three steps are performed.
First step: A non-foamable powdered thermoplastic polyurethane resin composition (B) is charged into a mold preheated to 200 ° C. to 300 ° C., and the mold is inverted to remove excess powder material. A process of attaching and melting (B) with a uniform thickness on the mold surface. Second process: The foamable powdered thermoplastic polyurethane resin composition (A) is charged while (B) is attached to the mold. Inverting the mold to remove excess powder material and depositing (A) on the layer (B) with a predetermined thickness Third step: (A) layer in a heating oven at 200 to 400 ° C. And (B) the layered and adhered mold is placed for 30 to 120 seconds to complete the melting and foaming of the powdered resin, and then taken out of the heating oven and cooled to mold, and then the molded product is demolded. Process The method for producing a sheet-like polyurethane resin molded article having a two-layer structure according to claim 9 or 10, wherein the following three steps are performed.
First step: A non-foamable powdered thermoplastic polyurethane resin composition (B) is charged into a mold preheated to 200 ° C. to 300 ° C., and the mold is inverted to remove excess powder material. A process of attaching and melting (B) with a uniform thickness on the mold surface. Second process: The foamable powdered thermoplastic polyurethane resin composition (A) is charged while (B) is attached to the mold. The process of inverting the mold to remove excess powder material and depositing (A) on the layer (B) with a predetermined thickness Third process: (A) layer and (B) layer are laminated and adhered The mold is self-heated at 200 ° C. to 300 ° C. for 30 to 120 seconds to complete the melting and foaming of the powder resin, and then the mold is cooled and then the molded product is demolded