JP2009221292A - Resin powder for slash molding, method for producing the same, and the resultant molded form - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide resin powder for slash molding, enabling an air-bag to be normally expanded even under a high-temperature service environment. <P>SOLUTION: The resin powder for slash molding comprises a thermoplastic polyurethane resin (A) and a plasticizer (B); wherein, the content of the plasticizer (B) is 5-20 wt.% of the total weight of the thermoplastic polyurethane resin (A) and the plasticizer (B), and the concentration of the plasticizer (B) in the resin powder is uniform. A sheet obtained by slash molding from the above resin powder is also provided, being characterized by that its incision is not fused in undergoing a pressure fusing test. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a resin powder for slush molding, a resin molded body, and a method for producing a resin powder for slush molding. More specifically, the present invention relates to a resin powder for slush molding excellent in heat resistance suitable as a molding material for automobile interior parts such as instrument panels, a resin molded body, and a method for producing a resin powder for slush molding.

In recent years, slush molded products have been used for instrument panels for automobile interior parts. In order to deploy the airbag stored under the instrument panel, a cleavage opening is provided in the instrument panel. For the processing for the cleavage opening, a method of slitting the back surface of the instrument panel with a cutter is performed from the viewpoint of design.
As a material for preparing a slush molded product, an instrument panel skin molding material made of a thermoplastic polyurethane resin (A) having a glass transition temperature of −60 to −35 ° C. is known (Patent Document 1). ).
Japanese Patent Laid-Open No. 2003-300428

However, there is a problem that a slit processed by a cutter for deploying an airbag may be re-fused by heat due to a high temperature use environment, and normal cleavage may not occur when the airbag is deployed. On the other hand, if the addition amount of the plasticizer is decreased, re-fusion does not occur, but there is a problem that the meltability deteriorates during slush molding and the quality of the molded product deteriorates.
The problem to be solved by the present invention is to provide a resin powder for slush molding in which an airbag can be cleaved normally even under a high temperature use environment.

As a result of intensive studies, the present inventors have completed the present invention.
That is, the characteristic of the slush molding resin powder of the present invention is a slush molding resin powder comprising a thermoplastic polyurethane resin (A) and a plasticizer (B),
The content of the plasticizer (B) is 5 to 20% by weight based on the total weight of the thermoplastic polyurethane resin (A) and the plasticizer (B),
The concentration of the plasticizer (B) in one slush molding resin powder is uniform,
The gist is that the sheet formed by slush molding from the resin powder for slush molding does not melt the cut by the pressure fusion test method.

  The gist of the resin molded body of the present invention is that the resin powder is formed by slush molding.

The method for producing a resin powder for slush molding according to the present invention is a method for producing the above resin powder for slush molding,
A step (10) for producing thermoplastic polyurethane resin particles (K);
Step (20) of impregnating the thermoplastic polyurethane resin particles (K) with the plasticizer (B) until the concentration of the plasticizer (B) is uniform throughout the interior of the thermoplastic polyurethane resin particles (K).
The point including

  The slush molding resin powder of the present invention is excellent in airbag deployability because the slit processed by a cutter for deploying an airbag is not easily re-fused by heat even in a high temperature use environment. Moreover, since the meltability at the time of slush molding is excellent, the quality of the molded product does not deteriorate.

  The thermoplastic polyurethane resin (A) is not particularly limited as long as it is a constituent used for slush molding, and known constituents (for example, JP-A-2000-103957) can be used. A resin containing a low molecular diol and / or a low molecular diamine as a constituent component is included as required.

  The polymer polyol is preferably a polyester polyol and includes a known polyester polyol, from the viewpoint of airbag development (characteristic that the cut is not fused, hereinafter referred to as this characteristic).

  The polyisocyanate is preferably an alicyclic diisocyanate, an aliphatic diisocyanate, or a mixture thereof from the viewpoint of this property or the like, and includes known polyisocyanates.

  As the thermoplastic polyurethane resin (A), it is preferable that the polyester polyol and at least one of an alicyclic diisocyanate and an aliphatic diisocyanate are essential components from the viewpoint of this property and the like.

  The glass transition temperature (° C.) of the thermoplastic polyurethane resin (A) is preferably from −50 to −20, more preferably from −45 to −25, particularly preferably from −40 to 40, from the viewpoint of airbag development at low temperatures. -30.

  As the plasticizer (B), known plasticizers (for example, JP-A No. 2000-17032) can be used, and aromatic phosphate ester (B1), polyethylene glycol dibenzoate ester (B2), phthalate ester ( B3), aliphatic dibasic acid ester (B4), trimellitic acid ester (B5), aliphatic ester (B6), aliphatic phosphoric acid ester (B7), halogen aliphatic aliphatic phosphoric acid ester (B8) and two or more thereof A mixture of

  Among these plasticizers, scratch resistance and gloss unevenness of a resin molded product obtained by slush molding resin powder (refers to a phenomenon in which a plasticizer is deposited on a mold every molding, and gloss varies depending on the part of the molded product. ) And the like, the aromatic phosphate ester (B1) is preferable.

  The aromatic phosphate ester (B1) is not particularly limited as long as it is an aromatic phosphate ester. For example, Daihachi Chemical Co., Ltd., plasticizer CR-741, etc. are preferably used.

  Although the detailed chemical structure of the plasticizer CR-741 has not been clarified, it is presumed that it is synthesized from trichlorophosphoric acid, bisphenol A and phenol and has the following chemical structure or a similar chemical structure. The

When the plasticizer (B) is an aromatic phosphate ester (B1), in the infrared absorption analysis of the resin powder for slush molding of the present invention, a urea peak specific to the thermoplastic polyurethane resin (A) (around 1640 cm ⁻¹ ) It is preferable that the ratio (b / a) of the area (b) of the aromatic ring peak (near 731 cm ⁻¹ ) specific to the aromatic phosphate ester (B1) to the area (a) is 1.3 or less, Preferably it is 1.3-1.0, Most preferably, it is 1.25-1.1. Within this range, the amount of plasticizer on the surface of the resin powder is small, meaning that the plasticizer is more uniformly impregnated into the powder.

The ratio (b / a) is determined by using an infrared absorption analyzer (for example, FTIR-8400, Shimadzu Corporation), placing about 1 to 5 samples on a diamond sensor, and pressing the sensor with a sample pressing rod, 650 Infrared absorption analysis is performed at ˜4000 cm ⁻¹ and the number of integrations of 128, and the peak area is calculated with both ends of the specific peak as a range to obtain the ratio (b / a).

  In order to set the ratio (b / a) within the above range, (1) the content of the plasticizer (B) is set within the range described later, and (2) the impregnation temperature of the plasticizer (B) is within the range described below. And / or (3) the impregnation time of the plasticizer (B) is in the range of 2 to 8 hours.

  The content (% by weight) of the plasticizer (B) is 5 to 20, more preferably 6 to 18, particularly preferably based on the total weight of the thermoplastic polyurethane resin (A) and the plasticizer (B). Is 9-15. If the amount is less than this range, almost no plastic effect is obtained. On the other hand, if the range is exceeded, uniformity of the plasticizer (B) to the thermoplastic polyurethane resin (A) cannot be obtained, and one slush molding resin powder The concentration of the plasticizer (B) therein is not uniform.

The concentration of the plasticizer (B) in one slush molding resin powder of the present invention is uniform.
In addition, that the density | concentration of the plasticizer (B) in one resin powder for slush molding is uniform means that the density | concentration of a plasticizer (B) is uniform to the whole inside of one resin powder grain.

It can be confirmed by the plasticizer impregnation measuring method that the concentration of the plasticizer (B) in one slush molding resin powder of the present invention is uniform.
The measuring method of the plasticizer impregnation property is as follows.

<Plasticizer impregnation>
After cutting out a cross-sectional piece of the resin powder for slush molding using an ultramicrotome (for example, LEICA ultramicrotome) (the cross-sectional piece is cut out near the center of the resin powder. The thickness of the cross-sectional piece is 1 to 3 μm), Nine locations (for example, nine locations numbered 1 to 9 in FIG. 1 are suitable) of the cut-out cross-sectional piece are analyzed with a micro-infrared spectroscopic analyzer, and a peak peculiar to the plasticizer (B) (for example, plasticity). The peak specific to the agent CR-741 is 731 cm ⁻¹ ), and the variation is determined according to the following criteria.

  If the standard deviation (σ) of the peak area is 50 or less, it can be determined that the concentration of the plasticizer (B) is uniform throughout the resin powder, while the standard deviation (σ) of the peak area is 51. When it is above, it cannot be said that the concentration of the plasticizer (B) is uniform throughout the resin powder.

  In order to make the concentration of the plasticizer (B) uniform in one particle of the resin powder, (1) the content of the plasticizer (B) is within the above range, (2) impregnation of the plasticizer (B) It can be achieved by setting the temperature within the range described below and / or (3) setting the impregnation time of the plasticizer (B) in the range of 2 to 8 hours.

With respect to the sheet slush-molded from the slush molding resin powder of the present invention, the cut is not fused by the pressure fusion test method. By making the concentration of the plasticizer (B) in one slush molding resin powder of the present invention uniform, it becomes difficult for the cuts to be fused by the pressure fusion test method.
The sheet is filled with a Ni electric mold with a wrinkle pattern preheated to 270 ° C., filled with resin powder for slush molding, discharged after 10 seconds, heated at 250 ° C. for 90 seconds, and then cooled with water. Then, it is prepared by cutting into a thickness of 0.8 to 2.0 mm, a length of 6.0 cm, and a width of 9.5 cm.

<Pressure-fusion test method>
With a cold cutter (blade thickness 0.3 mm), the depth is approximately perpendicular to the longitudinal direction of the sheet with respect to the back surface of the sheet (the surface in contact with the Ni electroforming mold is the front surface and the opposite surface is the back surface). A cut of 0.4 to 0.6 mm and a length of 6.0 cm is made, and the sheet is sandwiched between two release papers. On the release paper, an iron plate (weight 95 to 100 g, length 10 cm × width 10 cm) X thickness 1.2 mm) is placed so that the release paper is hidden, and is left to stand at 130 ° C. for 100 hours in the air at atmospheric pressure, and then visually observed whether the cuts made in the sheet are fused. .

  The slush molding resin powder of the present invention may contain known additives (such as release agents, pigments, antioxidants, weathering stabilizers and antiblocking agents).

The method for producing a resin powder for slush molding of the present invention comprises a step (10) of producing thermoplastic polyurethane resin particles (K),
And (20) impregnating the thermoplastic polyurethane resin particles (K) with the plasticizer (B) until the concentration of the plasticizer (B) is uniform throughout the interior of the thermoplastic polyurethane resin particles (K). preferable.

  A known method can be applied to the step (10) of producing the thermoplastic polyurethane resin particles (K), and for example, it can be produced by the following method.

(1) A method of reacting an isocyanato group-terminated urethane prepolymer with a blocked chain extender (for example, ketimine) in the presence of water and a dispersion stabilizer (JP-A-8-120041, etc.).

(2) A method of reacting a urethane prepolymer having a urethane bond and a urea bond with a chain extender (for example, diamine, diol) in the presence of an organic solvent in which the urethane prepolymer does not dissolve and a dispersion stabilizer 4-202331 etc.).

(3) After reacting a diisocyanate, a high molecular diol, and a chain extender (low molecular diol, low molecular diamine) as necessary, pulverization (for example, freeze pulverization, cutting through pores in a molten state) How to).

  10-500 are preferable and, as for the volume average particle diameter (micrometer) of a thermoplastic polyurethane resin particle (K), 70-300 are more preferable.

  The volume average particle diameter is measured by a laser diffraction particle size distribution measuring apparatus having a measurement principle based on JIS Z8825-1-2001 “Particle Size Analysis—Laser Diffraction Method” (for example, Shimadzu Corporation, SALD-1100, Horiba, Ltd.). Mfg. Co., Ltd., LA-920 etc.).

  In the step (20) of impregnating the thermoplastic polyurethane resin particles (K) with the plasticizer (B) until the concentration of the plasticizer (B) is uniform throughout the interior of the thermoplastic polyurethane resin particles (K), the plasticizer ( B) may be impregnated after the production of the thermoplastic polyurethane resin particles (K) by mixing with a pigment and / or a stabilizer added as necessary.

  As an impregnation temperature (degreeC) of a plasticizer (B), 60-85 are preferable, More preferably, it is 65-80. Within this range, the concentration of the plasticizer (B) in one slush molding resin powder tends to be uniform.

  It can be confirmed by the measuring method of the plasticizer impregnation property that the concentration of the plasticizer (B) is uniform throughout the thermoplastic polyurethane resin particles (K).

When the plasticizer (B) is an aromatic phosphate ester (B1), the method for producing a resin powder for slush molding of the present invention includes a step (10) of producing thermoplastic polyurethane resin particles (K),
In infrared absorption analysis of resin powder for slush molding,
Area of the thermoplastic polyurethane resin (A) to the peak of specific aromatic ring aromatic phosphoric ester (B1) to the area (a) of the peak of specific urea (1640 cm around ^{-1) (731cm} around ^-1) (b) It is preferable to include the step (21) of impregnating the thermoplastic polyurethane resin particles (K) with the aromatic phosphate ester (B1) until the ratio (b / a) of 1.3 is 1.3 or less.

Area of the thermoplastic polyurethane resin (A) to the peak of specific aromatic ring aromatic phosphoric ester (B1) to the area (a) of the peak of specific urea (1640 cm around ^{-1) (731cm} around ^-1) (b) The ratio (b / a) is preferably 1.3 or less, more preferably 1.3 to 1.0, and particularly preferably 1.25 to 1.1. Within this range, the amount of plasticizer on the surface of the resin powder is small, and the plasticizer can be impregnated more uniformly into the interior.

  In the impregnation step (20 or 21), as a mixing device to be used, a known powder mixing device or the like can be used, and a container rotating type mixer, a fixed container type mixer, a fluid motion type mixer and the like are included. Among these, a fixed container type mixer is preferable.

  As a fixed container type mixer, a high-speed flow type mixer, a double-shaft paddle type mixer, a high-speed shear mixer (Henschel mixer, etc., “Henschel mixer” is a registered trademark of Mitsui Mining Co., Ltd.), and a low-speed mixer. Examples thereof include a mixing device (planetary mixer and the like) and a conical screw mixer (Nauta mixer and the like, “Nauta mixer” is a registered trademark of Hosokawa Micron Corporation). Among these, a double-shaft paddle type mixer, a low speed mixing device (planetary mixer or the like), and a conical screw mixer (Nauta mixer or the like) are preferable.

The resin powder for slush molding of the present invention can be molded into a resin molded body by a slush molding method.
As the slush molding method, for example, both the box containing the resin powder of the present invention and a heated mold are vibrated and rotated, and after the resin powder is melted and flowed in the mold, the molten resin is cooled and solidified, A method for producing a resin molded body (skin etc.) is included.

  As temperature (degreeC) of a metal mold | die, 200-300 are preferable, More preferably, it is 210-280.

  The resin molded body molded from the slush molding resin powder of the present invention by slush molding is preferably a sheet, and more preferably an automobile interior material (for example, an instrument panel or a door trim skin).

  The thickness (mm) of the sheet is preferably 0.5 to 1.5.

  The resin molded body (molded skin, etc.) can be set as a resin molded product with a foamed layer by setting the surface so as to be in contact with the foaming mold, pouring urethane foam, and forming a foamed layer of 5 mm to 15 mm on the back surface. .

  The resin molded body of the present invention is suitable for automobile interior materials (for example, instrument panels, door trims, etc.).

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

<Production Example 1>
Production of Prepolymer Solution In a reaction vessel equipped with a thermometer, a stirrer and a nitrogen blowing tube, polybutylene adipate (497.9 parts) having a number average molecular weight (hereinafter referred to as Mn) of 1000 and polyhexamethylene having an Mn of 900 Isophthalate (124.5 parts), pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] [Ciba Specialty Chemicals Co., Ltd .; Irganox 1010, “Irganox” Ciba Specialty Chemicals Holding, Inc. is a registered trademark. ] (1.12 parts) and kaolin (90.7 parts) having a volume average particle size of 9.2 μm were purged with nitrogen, heated to 110 ° C. with stirring and melted, and then cooled to 60 ° C. did. Subsequently, 1-octanol (9.7 parts), hexamethylene diisocyanate (153.4 parts), tetrahydrofuran (125 parts), 2- (2H-benzotriazol-2-yl) -6- ( Linear and side chain dodecyl) -4-methylphenol [Ciba Specialty Chemicals Co., Ltd .; Tinuvin 571, “Tinuvin” is a registered trademark of Ciba Specialty Chemicals Holding, Inc. (2.22 parts) was added and reacted at 85 ° C. for 6 hours to obtain a prepolymer solution (D ′). The NCO content of the prepolymer solution (D ′) was 2.05%.

  Polycarbodiimide derived from tetramethylxylylene diisocyanate [Mn 15,000, terminal group: methoxy group, property: 70% methyl ethyl ketone (hereinafter referred to as MEK) solution, Nisshinbo Co., Ltd .; Carbolite V- 09B] (2.15 parts) was added and reacted at 85 ° C. for 6 hours to obtain a prepolymer solution (D). The NCO content of the prepolymer solution (D) was 2.05%.

<Production Example 2>
Production of MEK ketimine product of diamine Hexamethylenediamine and excess MEK (4-fold molar amount with respect to diamine) were refluxed at 80 ° C. for 24 hours, and the generated water was removed from the system. Thereafter, unreacted MEK was removed under reduced pressure to obtain a MEK ketiminate.

<Production Example 3>
Production of thermoplastic resin particles Into a reaction vessel, the prepolymer solution (D) obtained in Production Example 1 (100 parts) and the MEK ketimine compound obtained in Production Example 2 (5.6 parts) are charged, and diisobutylene is added thereto. Dissolving agent containing sodium salt of copolymer of maleic acid and maleic acid (Sanyo Kasei Kogyo Co., Ltd., Sunspearl PS-8, “Sunspearl” is a registered trademark of the company) (1.3 parts) 340 parts of an aqueous solution was added and mixed for 1 minute at a rotation speed of 9000 rpm using Yamato Scientific Co., Ltd., Ultra Disperser. This mixture was transferred to a reaction vessel equipped with a thermometer, a stirrer and a nitrogen blowing tube, purged with nitrogen, and then reacted at 50 ° C. for 10 hours with stirring. After completion of the reaction, filtration and drying were performed to produce thermoplastic resin particles (K). Mn of (K) was 25,000, the volume average particle diameter was 146 μm, and the glass transition temperature was −35 ° C.

<Example 1>
In a 100 L Nauta mixer, thermoplastic resin particles (K) (100 parts), plasticizer (reaction product of aromatic condensed phosphate ester, trichlorophosphoric acid, bisphenol A and phenol) [Dahachi Chemical Co., Ltd .; CR- 741] (B11) (6.0 parts), dipentaerythritol pentaacrylate [Sanyo Chemical Industries, Ltd .; DA600] (3.9 parts), and bis (1,2,2,6,6-pentamethyl-4- Piperidyl) sebacate and methyl 1,2,2,6,6-pentamethyl-4-piperidyl sebacate (mixture) [trade name: TINUVIN 765, manufactured by Ciba Co., Ltd.] (0.27 parts) were added at 70 ° C. and 2 The resin powder (E1) was obtained by mixing uniformly over time. When the plasticizer impregnation property and infrared peak ratio (b / a) of the resin powder (E1) were measured, the standard deviation (σ) of the plasticizer impregnation property was 20, and the ratio (b / a) was 1.15. Met.
The plasticizer impregnation property was analyzed by micro-infrared spectroscopy (hereinafter, the same applies) at the 9 positions shown in FIG. 1 with respect to a peak 731 cm ⁻¹ peculiar to the plasticizer (B).

  To the resin powder (E1), dimethylpolysiloxane [Nihon Unicar Co., Ltd .; Kei L45-1000] (0.1 part) and carboxyl-modified silicone [Shin-Etsu Chemical Co., Ltd .; X-22-3710] (0.1 part) And mixed for 1 hour, and then cooled to room temperature (about 25 ° C.). Cross-linked polymethyl methacrylate [Gantz Kasei Co., Ltd .; Gantz Pearl PM-030S, “Gantz Pearl” is a registered trademark of the same company. ] (0.3 parts) was added and uniformly mixed to obtain a slush molding resin powder (C1) of the present invention. The volume average particle diameter of the resin powder (C1) was 150 μm. The plasticizer (B) content was 5.4%.

<Example 2>
Other than changing the amount of the plasticizer (B11) from “6.0 parts” to “12.0 parts” and changing the time of uniform mixing at 70 ° C. from “2 hours” to “4 hours”, Resin powder (E2) was obtained in the same manner as Example 1. When the plasticizer impregnation property and infrared peak ratio (b / a) of the resin powder (E2) were measured, the ratio (b / a) was 1.20. The standard deviation (σ) for the plasticizer impregnation property was 22.

  Using the resin powder (E2), a slush molding resin powder (C2) of the present invention was obtained in the same manner as in Example 1. The volume average particle diameter of the resin powder (C2) was 155 μm. The plasticizer (B) content was 10.3%.

<Example 3>
Other than changing the amount of the plasticizer (B11) from “6.0 parts” to “26.0 parts” and changing the time of uniform mixing at 70 ° C. from “2 hours” to “8 hours”, Resin powder (E3) was obtained in the same manner as Example 1. When the plasticizer impregnation property and infrared peak ratio (b / a) of the resin powder (E3) were measured, the ratio (b / a) was 1.15. The standard deviation (σ) of the plasticizer impregnation property was 29.

  Using the resin powder (E3), a slush molding resin powder (C3) of the present invention was obtained in the same manner as in Example 1. The volume average particle diameter of the resin powder (C3) was 160 μm. The plasticizer (B) content was 18.7%.

<Example 4>
“Plasticizer (B11) 6.0 parts” was changed to “Plasticizer (B21) [Polyethylene glycol dibenzoate ester, Sanyo Chemical Industries, Ltd .; Sunfix EB300] 12.0 parts” and at 70 ° C. Resin powder (E4) was obtained in the same manner as in Example 1 except that the uniformly mixed time was changed from “2 hours” to “4 hours”. The standard deviation (σ) of the plasticizer impregnation property of the resin powder (E4) was 15.

  Using the resin powder (E4), a slush molding resin powder (C4) of the present invention was obtained in the same manner as in Example 1. The volume average particle diameter of the resin powder (C4) was 154 μm. The plasticizer (B) content was 10.3%.

<Comparative Example 1>
Resin powder (E5) was obtained in the same manner as in Example 1 except that the amount of the plasticizer (B11) was changed from “6.0 parts” to “4.0 parts”. When the plasticizer impregnation property and infrared peak ratio (b / a) of the resin powder (E5) were measured, the ratio (b / a) was 1.10. The standard deviation (σ) for the plasticizer impregnation property was 16.

  Using the resin powder (E5), a comparative slush molding resin powder (H1) was obtained in the same manner as in Example 1. The volume average particle diameter of the resin powder (H1) was 149 μm. The plasticizer (B) content was 3.7%.

<Comparative Example 2>
Other than changing the amount of the plasticizer (B11) from “6.0 parts” to “27.0 parts” and changing the time of uniform mixing at 70 ° C. from “2 hours” to “10 hours”, Resin powder (E6) was obtained in the same manner as Example 1. When the plasticizer impregnation property and the infrared peak ratio (b / a) of the resin powder (E6) were measured, the ratio (b / a) was 1.48. The standard deviation (σ) for the plasticizer impregnation property was 344.

  Using the resin powder (E6), a comparative slush molding resin powder (H2) was obtained in the same manner as in Example 1. The volume average particle diameter of the resin powder (H2) was 160 μm. The plasticizer (B) content was 22.3%.

<Comparative Example 3>
Resin powder (E7) was obtained in the same manner as in Example 1 except that the time of uniform mixing at 70 ° C. was changed from “2 hours” to “1 hour”. When the plasticizer impregnation property and infrared peak ratio (b / a) of the resin powder (E7) were measured, the ratio (b / a) was 1.53. The standard deviation (σ) for the plasticizer impregnation property was 496.

  Using the resin powder (E7), a comparative slush molding resin powder (H3) was obtained in the same manner as in Example 1. The volume average particle diameter of the resin powder (H3) was 155 μm. The plasticizer (B) content was 10.3%.

<Comparative example 4>
Resin powder (E8) was obtained in the same manner as in Example 1 except that the amount of the plasticizer (B11) was changed from “6.0 parts” to “12.0 parts”. When the plasticizer impregnation property and infrared peak ratio (b / a) of the resin powder (E8) were measured, the ratio (b / a) was 1.62. The standard deviation (σ) of the plasticizer impregnation property was 363.

  Using the resin powder (E8), a slush molding resin powder (H4) for comparison was obtained in the same manner as in Example 1. The volume average particle diameter of the resin powder (H4) was 155 μm. The plasticizer (B) content was 10.3%.

<Comparative Example 5>
Except for changing the amount of the plasticizer (B11) from “6.0 parts” to “26.0 parts” and changing the uniform mixing time at 70 ° C. from “2 hours” to “4 hours”, Resin powder (E9) was obtained in the same manner as Example 1. When the plasticizer impregnation property and infrared peak ratio (b / a) of the resin powder (E9) were measured, the ratio (b / a) was 1.58. The standard deviation (σ) for the plasticizer impregnation property was 393.

  Using the resin powder (E9), a comparative slush molding resin powder (H5) was obtained in the same manner as in Example 1. The volume average particle diameter of the resin powder (H5) was 155 μm. The plasticizer (B) content was 18.7%.

<Comparative Example 6>
Resin powder (E10) was obtained in the same manner as in Example 1, except that “Plasticizer (B11) 6.0 parts” was changed to “Plasticizer (B21) 12.0 parts”. When the plasticizer impregnation property of the resin powder (E10) was measured, the standard deviation (σ) was 380.

  Using the resin powder (E10), a slush molding resin powder (H6) for comparison was obtained in the same manner as in Example 1. The volume average particle diameter of the resin powder (H6) was 155 μm. The plasticizer (B) content was 10.3%.

For the slush molding resin powders (C1) to (C4) obtained in Examples 1 to 4 and the slush molding resin powders (H1) to (H6) obtained in Comparative Examples 1 to 6, a pressure fusion test ( A sheet having a thickness of 1 mm was prepared and measured.) And the backside meltability was evaluated, and the results are shown in Table 1. In addition, about the sheet | seat using the resin powder (H1) obtained by the comparative example 1, although the pressure-fusion test was "no fusion | fusion," there exists a pinhole penetrated on the surface and it cannot use for practical use. .
Moreover, the plasticizer impregnation property was evaluated, and the peak area of the plasticizer and the standard deviation (σ) thereof at each measurement point (FIG. 1) are shown in Table 2.

<Backside meltability>
The meltability was evaluated based on the following criteria for the central part of the back surface of the test piece for which the pressure fusion test was completed.
5: Uniform and glossy.
4: There is a partially unmelted powder, but it is glossy.
3: There are irregularities on the entire back surface and there is no gloss. There are no pinholes penetrating the surface.
2: There are irregularities in the form of powder on the entire back surface, and there are pinholes penetrating the surface.
1: The powder does not melt and does not become a molded product.

  The slush molding resin powder of the present invention is suitably used as an automobile interior material (for example, a skin of an instrument panel, a door trim, etc.).

When evaluating plasticizer impregnation property, it is a cross-sectional view schematically showing portions (numbers 1 to 9 in the figure) that are suitable for analysis with a micro-infrared spectroscopic analyzer among cross-sectional pieces of resin powder is there.

Claims (8)

A slush molding resin powder comprising a thermoplastic polyurethane resin (A) and a plasticizer (B),
The content of the plasticizer (B) is 5 to 20% by weight based on the total weight of the thermoplastic polyurethane resin (A) and the plasticizer (B),
The concentration of the plasticizer (B) in one slush molding resin powder is uniform,
A slush molding resin powder, characterized in that a sheet formed by slush molding from a slush molding resin powder is not fused by a pressure fusion test method. The resin powder for slush molding according to claim 1, wherein the thermoplastic polyurethane resin (A) comprises a polyester polyol and at least one of an alicyclic diisocyanate and an aliphatic diisocyanate as essential components. The plasticizer (B) is an aromatic phosphate ester (B1),
In infrared absorption analysis, the aromatic ring peak (around 731 cm ⁻¹ ) specific to the aromatic phosphate ester (B1) with respect to the area (a) of the urea peak (near 1640 cm ⁻¹ ) characteristic of the thermoplastic polyurethane resin (A) The ratio (b / a) of the area (b) to 1.3 or less is a resin powder for slush molding according to claim 1 or 2. The resin powder for slush molding according to any one of claims 1 to 3, wherein the thermoplastic polyurethane resin (A) has a glass transition temperature of -50 to -20 ° C. The resin molding formed by carrying out the slush molding of the resin powder of any one of Claims 1-4. The resin molded product according to claim 5, which is an automobile interior material. A method for producing a resin powder for slush molding according to any one of claims 1 to 4,
A step (10) for producing thermoplastic polyurethane resin particles (K);
Step (20) of impregnating the thermoplastic polyurethane resin particles (K) with the plasticizer (B) until the concentration of the plasticizer (B) is uniform throughout the interior of the thermoplastic polyurethane resin particles (K).
The manufacturing method of the resin powder for slush molding containing these. A method for producing a resin powder for slush molding according to claim 3 or 4,
A step (10) for producing thermoplastic polyurethane resin particles (K);
In infrared absorption analysis of resin powder for slush molding,
Area of the thermoplastic polyurethane resin (A) to the peak of specific aromatic ring aromatic phosphoric ester (B1) to the area (a) of the peak of specific urea (1640 cm around ^{-1) (731cm} around ^-1) (b) Step (21) of impregnating the thermoplastic polyurethane resin particles (K) with the aromatic phosphate ester (B1) until the ratio (b / a) of 1.3 or less
The manufacturing method of the resin powder for slush molding containing these.

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