JP5825148B2 - Resin fusing test method - Google Patents

Description

The present invention relates to a method for inspecting a thermoplastic resin molded article (skin) formed by molding a thermoplastic resin material.

  In recent years, slush molded products obtained by slush molding a thermoplastic resin material are 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.

JP 2007-283865 A JP 2002-326241 A JP-A-8-1696

However, for the purpose of low-temperature molding during slush molding, a molded product made of a good-melting thermoplastic resin with reduced intermolecular bond strength in the resin can be used without any particular problem under normal actual use environment. Under high temperature usage conditions, it has been found that the cut surface of the slit processed by the cutter develops stickiness, the cut surface adheres with adhesive force, and the molecular chains of the adhesive surface may become entangled and fused over time. It was.
As a method for evaluating the fusion of the slit in a high temperature environment, until now, a thermoplastic resin molded product actually provided with a slit on the back surface is left in a high temperature use environment for a certain period of time, and the slit is fused. However, there has been a problem that it takes a long time for evaluation, and it has taken time to develop a thermoplastic resin. Further, until now, it has been tried whether the evaluation can be made by measuring the softening temperature of the thermoplastic resin molded article or the tensile viscoelasticity of the thermoplastic resin molded article, but it has not always been possible to accurately evaluate the fusion of the slit.
The problem to be solved by the present invention is to develop an inspection method capable of accurately evaluating in a short time whether or not the slit on the back surface of the instrument panel is fused in a high temperature environment.

As a result of intensive studies, the present inventors have completed the present invention.
The present invention relates to whether or not the slit formed on the back surface of the skin (L) obtained by slush molding the thermoplastic resin powder (P) and used for an instrument panel of an automobile interior part is fused in a high temperature environment. It is an inspection method, the skin (L) is prepared using the thermoplastic resin powder (P), the shear dynamic viscoelasticity of the skin (L) is measured, and the shear storage elastic modulus (x) is obtained ( This is a method for inspecting a thermoplastic resin skin for an instrument panel that determines whether or not the skin (L) is not fused at or below the dynamic viscoelasticity measurement temperature from the measured value of x).

In the inspection method of the present invention, a slit formed on the back surface of an outer skin (L) used for an instrument panel of an automobile interior part is measured by dynamic viscoelasticity from a shear storage modulus (x) obtained by measuring shear dynamic viscoelasticity. It can be determined in a short time and accurately that it does not fuse at the temperature.

The reason why the slit formed on the back surface of the skin (L) used for instrument panels of automobile interior parts is fused in a high temperature environment is that the skin is softened by heat, and stickiness is developed. This is presumably because the adhesive force is expressed by the force, and the molecular chains on the adhesive surface are entangled and fused over time. In the method of the present invention, the presence or absence of the above-mentioned adhesion can be predicted by measuring the storage elastic modulus of the test resin.

As a method of creating the skin before the shear dynamic viscoelasticity measurement using the thermoplastic resin powder (P), pressure molding (molding machine: pressure press machine, molding method: preferably 160 to 220 ° C. both above and below the press part, More preferably, 5 to 20 g, preferably 8 to 12 g of powder sandwiched between release papers is set in a pressure press machine whose temperature is adjusted to 170 to 190 ° C., and 0.2 to 0.4 MPa for 1 minute, preferably 0.8. It can be obtained by press-molding at a pressure of 25 to 0.35 MPa and then removing from the release paper after cooling. In pressure molding, if there is a gap between powders due to insufficient melting of the resin in the skin, it is impossible to accurately measure the shear storage modulus.

The plate thickness of the skin before the measurement of the shear dynamic viscoelasticity is 1.0 to 2.0 mm from the viewpoint of the accuracy of the measurement value of the shear storage modulus. The preferred plate thickness is 1.25 to 1.75 mm. The shape of the measurement sample is a cylinder, the size is 10 mm, the diameter is the same as that of the shearing dynamic viscoelastic jig, and the height is 1.0 to 2.0 mm.

Common methods for measuring dynamic viscoelasticity include bending, tension, compression, and shearing.
Since the measurement method of dynamic viscoelasticity of the present invention is high-temperature measurement, it is appropriate to perform shear measurement that is not easily affected by gravity during material deformation.

  The measuring device for dynamic viscoelasticity is not limited as long as it can measure shear dynamic viscoelasticity, but includes a dynamic viscoelasticity measuring device “RDS-2” (manufactured by Rheometric Scientific).

In order to accurately measure the shear storage modulus obtained by shear dynamic viscoelasticity measurement, the skin (L) molded using the thermoplastic resin powder (P) of the present invention is treated for shear dynamic viscoelasticity measurement. It is necessary to fix it to the tool. As a fixing method, it is appropriate to set the skin (L) on a jig of a dynamic viscoelasticity measuring apparatus, and heat and melt it so as to be in close contact with the jig. Adhering with an adhesive or the like is not preferable because it is affected by the storage elastic modulus of the adhesive itself.

The measurement temperature of dynamic viscoelasticity is preferably 100 to 150 ° C, more preferably 110 to 140 ° C. Regarding the airbag deployment test of instrument panels for automotive interior parts, we assumed that airbag deployment would occur after several years of use in high-temperature areas, and were allowed to stand at a high temperature of 100 to 150 ° C for a certain period of time for each automobile manufacturer. An accelerated test, such as an airbag deployment test, has been conducted later. Therefore, also in the inspection method of this invention, it is preferable to evaluate at 100-150 degreeC.

The measurement frequency of dynamic viscoelasticity is 0.01 to 1.00 Hz, preferably 0.01 to 0.10 Hz, and more preferably 0.01 Hz. As for airbag deployment test of instrument panels for automotive interior parts, airbag deployment test after leaving for a certain time at high temperature for each automobile manufacturer, assuming airbag deployment after several years of use in high temperature area Therefore, a small frequency close to the stationary condition is appropriate.

The shear storage modulus (x) is a time when the numerical value is stable from the start of measurement, for example, a numerical value after 60 minutes is read. As long as the numerical value is stable, the shear storage modulus at any time may be read.

When the measured value of the shear storage modulus (x) is 0.1 MPa or more, it can be determined that the slit of the skin (L) is not fused even at a temperature lower than the dynamic viscoelasticity measurement temperature for a long time. Preferably, it is 0.15 MPa or more.

Examples of the thermoplastic resin used for the thermoplastic resin powder (P) include polyvinyl chloride resin, polyurethane resin, acrylic resin, polyolefin resin, and vinyl acetate resin such as styrene resin. Polyurethane resins and polyvinyl chloride resins are preferred.

The polyurethane resin is a resin composed of a high-molecular polyol, polyisocyanate, and a low-molecular diol, a low-molecular diamine, if necessary.
As the polymer polyol, polyester polyol is preferable.
As polyisocyanate, alicyclic diisocyanate, aliphatic diisocyanate, and a mixture of both are preferable.

The thermoplastic resin powder (P) can be molded into a resin molded body (skin) by a slush molding method.
As a slush molding method, for example, a box containing a thermoplastic resin powder (P) and a heated mold are both rotated and vibrated to melt and flow the resin powder (P) in the mold, A method of producing a resin molded body (skin) by cooling and solidification is included.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to this.

Production Example 1
Production of prepolymer solution (A-1) In a reaction vessel equipped with a thermometer, a stirrer and a nitrogen blowing tube, polybutylene adipate (360.5 parts) having a number average molecular weight (hereinafter referred to as Mn) of 1000, Polyhexamethylene isophthalate with Mn of 900 (240.3 parts), pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] [manufactured by Ciba Specialty Chemicals Co., Ltd. Irganox 1010] (1.2 parts), kaolin (87.7 parts) having a volume average particle diameter of 9.2 μm were charged, and after nitrogen substitution, the mixture was heated to 110 ° C. with stirring and melted to 60 ° C. Cooled down. Subsequently, 1-octanol (10.1 parts), hexamethylene diisocyanate (148.3 parts), tetrahydrofuran (150 parts), 2- (2H-benzotriazol-2-yl) -6- (linear and side chain dodecyl) ) -4-methylphenol [manufactured by Ciba Specialty Chemicals Co., Ltd .; Tinuvin 571] (1.8 parts) was added and reacted at 90 ° C. for 6 hours to obtain a prepolymer solution (A-1). The NCO content of (A-1) was 1.82%.

Production Example 2
Production of Prepolymer Solution (A-2) In a reaction vessel equipped with a thermometer, a stirrer and a nitrogen blowing tube, polybutylene adipate (408.6 parts) with Mn of 1000 and polyethylene phthalate with Mn of 2100 (108. 8 parts), pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] [manufactured by Ciba Specialty Chemicals, Inc .; Irganox 1010] (3.2 parts), A kaolin (15.5 parts) having a volume average particle size of 9.2 μm was charged and purged with nitrogen, then heated to 110 ° C. with stirring and melted, and cooled to 60 ° C. Subsequently, benzyl alcohol (6.3 parts), 1,4-chloromethylbenzene-2-ethylene trimellitate (7.0 parts), hexamethylene diisocyanate (131.2 parts), isophorone diisocyanate (4.5 parts) ), Tetrahydrofuran (300 parts), 2- (2H-benzotriazol-2-yl) -6- (linear and side chain dodecyl) -4-methylphenol [manufactured by Ciba Specialty Chemicals, Inc .; Tinuvin 571] (1.8 parts) was added and reacted at 90 ° C. for 6 hours to obtain a prepolymer solution (A-2). The NCO content of (A-2) was 1.42%.

Production Example 3
Production of prepolymer solution (A-3) In a reaction vessel equipped with a thermometer, a stirrer and a nitrogen blowing tube, polybutylene adipate (390.7 parts) with Mn of 1000 and polyhexamethylene isophthalate with Mn of 900 (210.4 parts), pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] [manufactured by Ciba Specialty Chemicals, Inc .; Irganox 1010] (1.2 Part), kaolin (87.7 parts) having a volume average particle size of 9.2 μm was charged and purged with nitrogen, then heated to 110 ° C. with stirring and melted, and cooled to 60 ° C. Subsequently, 1-octanol (9.2 parts), hexamethylene diisocyanate (147.9 parts), tetrahydrofuran (150 parts), 2- (2H-benzotriazol-2-yl) -6- (linear and side chain dodecyl) ) -4-methylphenol [manufactured by Ciba Specialty Chemicals Co., Ltd .; Tinuvin 571] (1.8 parts) was added and reacted at 90 ° C. for 6 hours to obtain a prepolymer solution (A-3). The NCO content of (A-3) was 1.82%.

Production Example 4
Production of Prepolymer Solution (A-4) In a reaction vessel equipped with a thermometer, a stirrer and a nitrogen blowing tube, polybutylene adipate (555.5 parts) with Mn of 1000 and polyethylene phthalate with Mn of 2100 (138.138). 9 parts), pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] [manufactured by Ciba Specialty Chemicals, Inc .; Irganox 1010] (1.39 parts), After charging kaolin (20.3 parts) having a volume average particle size of 9.2 μm and purging with nitrogen, the mixture was heated to 110 ° C. with stirring and melted, and cooled to 60 ° C. Subsequently, benzyl alcohol (9.4 parts), hexamethylene diisocyanate (142.6 parts), isophorone diisocyanate (4.8 parts), tetrahydrofuran (300 parts), 2- (2H-benzotriazol-2-yl)- 6- (Linear and side chain dodecyl) -4-methylphenol [manufactured by Ciba Specialty Chemicals Co., Ltd .; Tinuvin 571] (2.1 parts) was added and reacted at 90 ° C. for 6 hours to prepare a prepolymer solution ( A-4) was obtained. The NCO content of (A-4) was 1.77%.

Production Example 5
Production of MEK ketimine product of diamine (K-1) Hexamethylenediamine and excess MEK (4 times molar amount with respect to diamine) were refluxed at 80 ° C. for 24 hours, and the generated water was removed out of the system. Thereafter, unreacted MEK was removed under reduced pressure to obtain a MEK ketimine product (K-1) of diamine.

Production Example 6
Production of MEK ketimine product of diamine (K-2) Isophorone diamine 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 ketimine product (K-2) of diamine.

Production Example 7
Preparation of thermoplastic polyurethane resin powder (B-1) In a reaction vessel, the prepolymer solution (A-1) (100 parts) obtained in Production Example 1 and the MEK ketimine compound (K-1) obtained in Production Example 5 ( 4.7 parts), and a dispersant containing the sodium salt of a copolymer of diisobutylene and maleic acid (Sansu Pearl PS-8, manufactured by Sanyo Chemical Industries, Ltd.) (1.3 parts by weight) 315 parts by weight of the dissolved aqueous solution was added and mixed for 1 minute at a rotation speed of 9000 rpm using an ultradisperser manufactured by Yamato Scientific Co., Ltd. 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 a thermoplastic polyurethane resin powder (B-1). Mn of (B-1) was 21,000, and the volume average particle size was 155 μm.

Production Example 8
Production of Thermoplastic Polyurethane Resin Powder (B-2) In Production Example 7, the prepolymer solution (A-1) (100 parts) and the MEK ketimine compound (K-1) (4.7 parts) were added to the prepolymer solution (A -2) A thermoplastic polyurethane resin powder (B-2) was produced in the same manner as in Production Example 7, except that it was changed to (100 parts) and MEK ketimine compound (K-1) (3.5 parts). . Mn of (B-2) was 20,000, and the volume average particle diameter was 165 μm.

Production Example 9
Production of Thermoplastic Polyurethane Resin Powder (B-3) In Production Example 7, prepolymer solution (A-1) (100 parts) and MEK ketimine compound (K-1) (4.7 parts) were mixed with prepolymer solution (A -3) (100 parts), MEK ketimine compound (K-1) (3.8 parts), MEK ketimine compound (K-2) (1.2 parts) Thus, a thermoplastic polyurethane resin powder (B-3) was produced. Mn of (B-3) was 23,000, and the volume average particle size was 155 μm.

Production Example 10
Production of Thermoplastic Polyurethane Resin Powder (B-4) In Production Example 7, prepolymer solution (A-1) (100 parts) and MEK ketimine compound (K-1) (4.7 parts) were mixed with prepolymer solution (A -4) A thermoplastic polyurethane resin powder (B-4) was produced in the same manner as in Production Example 7, except that it was changed to (100 parts) and MEK ketimine compound (K-1) (4.5 parts). . Mn of (B-4) was 21,000, and the volume average particle size was 160 μm.

Production Example 11
Production of resin powder for slush molding (P-1) In a 100 L Nauta mixer, thermoplastic polyurethane resin powder (B-1) (100 parts), aromatic condensed phosphate ester [manufactured by Daihachi Chemical Co., Ltd. CR-741] (12.0 parts), dipentaerythritol pentaacrylate [manufactured by Sanyo Chemical Industries, Ltd .; DA600] (4.0 parts), 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] (0.27 parts) were added at 80 ° C. Mixed for 2 hours. Next, dimethylpolysiloxane [Nihon Unicar Co., Ltd .; Kei L45-1000] (0.1 part), carboxyl-modified silicon [Shin-Etsu Chemical Co., Ltd .; X-22-3710] (0.1 part), The mixture was added and mixed for 1 hour, and then cooled to room temperature. Finally, cross-linked polymethyl methacrylate [Ganz Kasei Co., Ltd .; Ganzpearl PM-030S] (0.3 parts) was added and mixed to obtain a slush molding resin powder composition (P-1). The volume average particle diameter of (P-1) was 158 μm.

Production Example 12
Manufacture example 11 of resin powder for slush molding (P-2) Changed thermoplastic polyurethane resin powder (B-1) (100 parts) to thermoplastic polyurethane resin powder (B-2) (100 parts) in Production Example 11. A slush molding resin powder powder (P-2) was produced in the same manner as in Production Example 11 except that this was done. The volume average particle diameter of (P-2) was 168 μm.

Production Example 13
Manufacture example 11 of resin powder for slush molding (P-3) Changed thermoplastic polyurethane resin powder (B-1) (100 parts) to thermoplastic polyurethane resin powder (B-3) (100 parts) in Production Example 11. A slush molding resin powder powder (P-3) was produced in the same manner as in Production Example 11 except that this was done. The volume average particle size of (P-3) was 156 μm.

Production Example 14
Manufacture example 11 of resin powder for slush molding (P-4) Changed thermoplastic polyurethane resin powder (B-1) (100 parts) to thermoplastic polyurethane resin powder (B-4) (100 parts) in Production Example 11. A slush molding resin powder powder (P-4) was produced in the same manner as in Production Example 11 except that this was done. The volume average particle size of (P-4) was 162 μm.

Example 1
10 g of polyurethane resin powder powder (P-1) for slush molding was subjected to pressure press molding at 180 ° C. and 0.3 MPa for 1 minute to prepare a molded skin (L1) having a plate thickness of 1 mm.
Next, 10 g of polyurethane resin powder powder (P-2) for slush molding was subjected to pressure press molding at 180 ° C. and 0.3 MPa for 1 minute to form a molded skin (L2) having a plate thickness of 1 mm.
Next, 10 g of polyurethane resin powder powder (P-3) for slush molding was subjected to pressure press molding at 180 ° C. and 0.3 MPa for 1 minute to prepare a molded skin (L3) having a plate thickness of 1 mm.
Next, 10 g of polyurethane resin powder powder (P-4) for slush molding was subjected to pressure press molding at 180 ° C. and 0.3 MPa for 1 minute to prepare a molded skin (L4) having a plate thickness of 1 mm.
Next, 10 g of polyvinyl chloride resin powder powder (P-5) for slush molding was subjected to pressure press molding at 180 ° C. and 0.3 MPa for 1 minute to produce a molded skin (L5) having a plate thickness of 1 mm.
As (P-5), a vinyl chloride homopolymer having an average polymerization degree of 1000 or more containing a trimellitate plasticizer was used.
Next, 10 g of poly-modified vinyl chloride resin powder powder (P-6) for slush molding was subjected to pressure press molding at 180 ° C. and 0.3 MPa for 1 minute to form a molded skin (L6) having a plate thickness of 1 mm.
As (P-6), a copolymer of vinyl chloride and an olefin having an average polymerization degree of 1000 or more containing a trimellitate plasticizer (the weight of vinyl chloride in the copolymer is 50 wt% or more) was used.

Next, using the obtained molded skins (L1) to (L6), the dynamic viscoelasticity measuring device “RDS-2” (manufactured by Rheometric Scientific) was used to slip each of the molded skins (L1) to (L6). The storage elastic modulus was measured. The jig used was a parallel plate for shear elasticity measurement. After cutting and setting the obtained molded skin so as not to protrude into the jig of the measuring device, the temperature was raised to 180 ° C., and melted by being allowed to stand between the jigs at 180 ° C. for 1 minute. It was made to adhere to a jig by cooling and solidifying. Thereafter, shear dynamic viscoelasticity was measured under the conditions of a measurement temperature of 130 ° C. and a frequency of 0.01 Hz, and the shear storage modulus after 60 minutes of measurement was read.
(L1) 130 ° C. shear storage modulus (x1) is 0.11 MPa, (L2) 130 ° C. shear storage modulus (x2) is 0.25 MPa, (L3) 130 ° C. shear storage modulus ( x3) is 0.02 MPa, (L4) 130 ° C shear storage modulus (x4) is 0.06 MPa, (L5) 130 ° C shear storage modulus (x5) is 0.08 MPa, (L6) 130 The shear storage modulus (x6) at 0 ° C. was 0.07 MPa.

Example 2
In Example 1, the shear storage modulus of the molded skins (L1) to (L6) was measured by the same method as in Example 1 except that the measurement temperature was changed from 130 ° C to 110 ° C.
(L1) 110 ° C. shear storage modulus (x1) is 0.82 MPa, (L2) 110 ° C. shear storage modulus (x2) is 2.20 MPa, (L3) 110 ° C. shear storage modulus ( x3) is 0.09 MPa, (L4) 110 ° C shear storage modulus (x4) is 0.45 MPa, (L5) 110 ° C shear storage modulus (x5) is 0.70 MPa, (L6) 110 The shear storage modulus (x6) at 0 ° C was 0.50 MPa.

Example 3
In Example 1, the shear storage modulus of the molded skins (L1) to (L6) was measured by the same method as in Example 1 except that the measurement temperature was changed from 130 ° C to 140 ° C.
(L1) 140 ° C. shear storage modulus (x1) is 0.07 MPa, (L2) 140 ° C. shear storage modulus (x2) is 0.11 MPa, (L3) 140 ° C. shear storage modulus ( x3) is 0.01 MPa, (L4) 140 ° C shear storage modulus (x4) is 0.02 MPa, (L5) 140 ° C shear storage modulus (x5) is 0.01 MPa, (L6) 140 The shear storage modulus (x6) at 0 ° C. was 0.01 MPa.

Example 4
In Example 1, the shear storage modulus of the molded skins (L1) to (L6) was measured by the same method as in Example 1 except that the frequency was changed from 0.01 Hz to 1.00 Hz.
(L1) 130 ° C shear storage modulus (x1) is 0.25 MPa, (L2) 130 ° C shear storage modulus (x2) is 0.40 MPa, (L3) 130 ° C shear storage modulus ( x3) is 0.05 MPa, (L4) 130 ° C. shear storage modulus (x4) is 0.08 MPa, (L5) 130 ° C. shear storage modulus (x5) is 0.08 MPa, (L6) 130 The shear storage modulus (x6) at 0 ° C. was 0.07 MPa.

Comparative Example 1
The slush-forming polyurethane resin powder (P-1) was filled in a Ni electric mold having a wrinkle pattern that had been heated to 250 ° C. in advance, and after 10 seconds, the excess polyurethane resin powder powder was discharged. After 60 seconds, it was cooled with water to prepare a 1 mm thick epidermis (L1 ′).
The slush-molding polyurethane resin powder (P-2) was filled in a Ni electric mold with a wrinkle pattern that had been heated to 230 ° C. in advance, and after 10 seconds, the excess polyurethane resin powder powder was discharged. After 60 seconds, it was cooled with water to prepare a 1 mm-thick skin (L2 ′).
The polyurethane resin powder powder for slush molding (P-3) was filled in a Ni electric mold having a wrinkle pattern heated in advance to 230 ° C., and after 10 seconds, the excess polyurethane resin powder powder was discharged. After 60 seconds, it was cooled with water to prepare a 1 mm thick skin (L3 ′).
The polyurethane resin powder powder (P-4) for slush molding was filled in a Ni electric mold with a wrinkle pattern that had been heated to 240 ° C. in advance, and after 10 seconds, excess polyurethane resin powder powder was discharged. After 60 seconds, it was water-cooled to prepare a 1 mm-thick skin (L4 ′).
The slush-molded polyvinyl chloride resin powder powder (P-5) was filled in a Ni electric mold having a wrinkle pattern heated in advance to 250 ° C., and after 10 seconds, the excess polyvinyl chloride resin powder powder was discharged. After 60 seconds, it was cooled with water to prepare a 1 mm-thick skin (L5 ′).
The slush-molded poly-modified vinyl chloride resin powder powder (P-6) was filled in a Ni electric mold with a wrinkle pattern that had been heated to 250 ° C in advance, and after 10 seconds, the excess poly-modified vinyl chloride resin powder powder was discharged. . After 60 seconds, it was cooled with water to prepare a 1 mm thick epidermis (L6 ′).

Using the obtained molded skins (L1 ′) to (L6 ′), cut into a size of 40 mm in length and 50 mm in width, and on the back surface of the sheet with a cutter (blade thickness: 0.3 mm), approximately perpendicular to the surface. A cut having a depth of 0.4 to 0.6 mm and a length of 50 mm was made. Put the molding skin between the release paper and put the iron plate with the weight of 95-100g from the top of the release paper and the dimensions (vertical, horizontal, height) 100mm vertical x 100mm horizontal x 1.2mm thick so that the release paper is hidden, and under normal pressure After standing at 130 ° C. for 100 hours, the non-fused portion of the sheet for 100 hours was calculated according to the following formula.
(L1 ′) 100-hour non-thermal fusion ratio (z1 ′) is 100%, (L2 ′) 100-hour non-thermal fusion ratio (z2 ′) is 100%, (L3 ′) 100-hour non-thermal fusion. Adhesion ratio (z3 ′) is 10%, (L4 ′) 100 hour non-thermal fusion ratio (z4 ′) is 50%, (L5 ′) 100 hour non-thermal fusion ratio (z5 ′) is 60%, The 100-hour non-thermal fusion ratio (z6 ′) of (L6 ′) was 50%.

Comparative Example 2
Using the molded skins (L1 ′) to (L6 ′) obtained in the same manner as in Comparative Example 1, the storage elastic modulus was measured with a dynamic viscoelasticity measuring device “Reogel-E4000” (manufactured by UBM). It was. The jig used was a jig for tensile elasticity measurement. The obtained molded skins (L1 ′) to (L6 ′) were cut into test pieces each having a width of 5 mm and a length of about 45 mm, set on a jig, and then tensioned at a measurement temperature of 130 ° C. and a frequency of 0.1 Hz. The dynamic viscoelasticity was measured, and the tensile storage modulus 60 minutes after the measurement was read.
The tensile storage elastic modulus (x1 ′) at 130 ° C. of (L1 ′) is 1.60 MPa, the tensile storage elastic modulus (x2 ′) at 130 ° C. of (L2 ′) is 1.20 MPa, and 130 ° C. of (L3 ′). Tensile storage modulus (x3 ′) is 0.80 MPa, (L4 ′) 130 ° C. tensile storage modulus (x4 ′) is 4.20 MPa, (L5 ′) 130 ° C. tensile storage modulus (x5 ′) Was 1.00 MPa, and the tensile storage modulus (x6 ′) at 130 ° C. of (L6 ′) was 0.80 MPa.

Comparative Example 3
Using molded skins (L1 ′) to (L6 ′) obtained by the same method as in Comparative Example 1, using a thermomechanical analyzer TMA / SS6100 and a data processing apparatus EXSTAR6000 [manufactured by SII Nanotechnology, Inc.] The thermal softening temperature was measured. The measurement conditions are a measurement temperature range of 25 to 250 ° C., a temperature increase rate of 5 ° C./min, a load of 5 g, and a needle diameter of 0.5 mm. As an analysis method after the measurement, “JIS K7121-1987, P.A. According to the method of “5, FIG. 3 stepwise change”, the intersection of the tangents of the TMA curve was determined and used as the thermal softening temperature.
(L1 ′) has a thermal softening temperature (y1 ′) of 140 ° C., (L2 ′) has a thermal softening temperature (y2 ′) of 131 ° C., (L3 ′) has a thermal softening temperature (y3 ′) of 125 ° C., (L4 ′) The thermal softening temperature (y4 ′) of ′) was 138 ° C., the thermal softening temperature (y5 ′) of (L5 ′) was 125 ° C., and the thermal softening temperature (y5 ′) of (L5 ′) was 122 ° C.

As a reference example for the examples and comparative examples, a long-term heat fusion test was performed in which the test was performed under conditions closer to actual conditions. If it is not fused in this long-term heat fusion test, it is regarded as not actually fused, and if it is fused in this long-term heat fusion test, it is regarded as actually fused to the same extent. Then, the measurement values of the examples were evaluated.
Using the molded skins (L1 ′) to (L6 ′) obtained by the same method as in Comparative Example 1, the long-term heat fusion test shown below was performed. The obtained long-term non-thermal fusion ratios (z1) to (z6) are the shear storage elastic moduli (x1) to (x6) of Examples 1 to 4, and the 100-hour non-thermal fusion ratio (z1 ′) of Comparative Example 1. ) To (z6 ′), tensile storage elastic modulus (x1 ′) to (x6 ′) of Comparative Example 2, and thermal softening temperatures (y1 ′) to (y6 ′) of Comparative Example 3 are shown in Table 1.

<How to make an epidermis>
10 g of polyurethane resin powder powder (P) for slush molding sandwiched between release papers was set in a pressure press machine whose temperature was adjusted to 180 ° C. both at the top and bottom of the press site, and after press molding at a pressure of 0.3 MPa for 1 minute, it was taken out. After cooling, it was peeled off from the release paper to obtain a molded skin having a thickness of 1 mm.

<Long-term non-thermal fusion ratio>
A 1 mm thick molded skin is cut into a size of 40 mm long and 50 mm wide, and a depth of 0.4 to 0. 0 is formed on the back surface of the sheet at a right angle to the surface with a cold cutter (blade thickness 0.3 mm). A slit of 6 mm and a length of 50 mm was made. A molded skin is sandwiched between release papers, and an iron plate with a weight of 95 to 100 g and dimensions (vertical, horizontal, height) of 100 mm x 100 mm x thickness 1.2 mm is placed on the release paper so that the release paper is hidden. Then, after standing for 1000 hours in air at normal temperature under normal temperature, the long-term non-thermal fusion ratio (z), which is the ratio of the unfused portion of the sheet, was calculated according to the following formula.

In Examples 1 to 4, if the shear storage modulus is 0.1 MPa or more, the long-term non-thermal fusion ratio at 110 to 140 ° C. is 100%, and if it is less than 0.1 MPa, the shear storage modulus is small. As such, the long-term non-thermal fusion ratio tends to decrease. Since this result and the measurement time of the shear storage elastic modulus are 60 minutes, it can be said that the shear storage elastic modulus can correctly evaluate the difficulty of fusion in a short time. In Comparative Example 1, the long-term non-thermal fusion ratio can be evaluated with a non-thermal fusion ratio of 100 hours, but the evaluation takes 100 hours. Further, Comparative Examples 2 and 3 cannot be evaluated because there is no tendency in the long-term non-heat melting ratio.

The inspection method of the present invention is suitably used as an evaluation method of whether or not the slit formed on the back surface of the skin (L) used in the instrument panel is fused in a high temperature environment.

Claims (4)

This is a method for inspecting whether a slit formed on the back surface of a skin (L) obtained by slush molding a thermoplastic resin powder (P) and used for an instrument panel of an automobile interior part is fused in a high temperature environment. Then, the skin (L) is prepared using the thermoplastic resin powder (P), the shear dynamic viscoelasticity is measured for the skin (L), the shear storage elastic modulus (x) is obtained, and the measurement of (x) is performed. The inspection method of the thermoplastic resin skin for instrument panels which judges whether skin (L) does not fuse below the dynamic viscoelasticity measurement temperature from a value. The inspection method according to claim 1, wherein the thermoplastic resin powder (P) is pressure-molded at 160 to 220 ° C. to produce a skin (L) having a plate thickness of 1.0 to 2.0 mm. The test | inspection method of Claim 1 or 2 which measures a shear dynamic viscoelasticity on 100-150 degreeC on the conditions of a frequency of 0.01-1.00 Hz about epidermis (L). The skin (L) determines that the measured value of the shear storage modulus (x) is 0.1 MPa or more and does not fuse at or below the dynamic viscoelasticity measurement temperature. Inspection method.