JPH1077403A - Resin composition for powder molding and molded article - Google Patents

Abstract

(57) [Summary] [PROBLEMS] Using thermoplastic polyurethane resin powder,
When a molded product having a matte and / or grained surface is manufactured by slush molding, it is difficult to maintain the surface state, and gloss is produced over time and the grained pattern disappears. SOLUTION: In a composition mainly composed of a thermoplastic polyurethane-based resin powder, a particle diameter of 0.1% which does not melt at a molding temperature.
Maleimide polymer particle powder of 5 to 200 μm is blended. A preferred particle powder is an N-cycloalkylmaleimide polymer having a number average molecular weight of 2,000 to 100,000, and a preferred compounding ratio is 0.5 to 5% by weight (based on the urethane resin powder).
It is. The resulting molded article does not increase in luster over time and does not lose its grain pattern, and does not impair its sense of quality or other appearance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for suppressing surface gloss,
The present invention relates to a resin composition for powder molding, which is mainly composed of a thermoplastic polyurethane resin powder and is suitable as a material for molding automotive interior parts such as so-called matted instrument panels and door trims.

[0002]

2. Description of the Related Art Conventionally, a vinyl chloride powder slush molded product is often used as a skin material for automobile interior parts such as instrument panels and door trims.

However, when vinyl chloride-based materials are used for a long period of time, the plasticizer contained therein is transferred to the surface by heat, light, etc., and the soft feeling is impaired. In addition, a problem has been pointed out that the incinerator is corroded by hydrogen chloride gas generated during the incineration treatment after scrapping the vehicle.

[0004] In order to solve these problems, development of powder slush molding materials mainly composed of thermoplastic polyurethane resin powder has been promoted. The powder slush molding method comprises filling a powder heated in a mold heated to 200 to 240 ° C., rotating and welding the powder to the inner surface of the mold, discharging the unwelded powder from the mold, and collecting the skin material. It is a method of molding.

[0005]

However, when the melting point of a thermoplastic polyurethane resin is adjusted so that powder slush molding can be performed, the skin surface of the thermoplastic polyurethane resin deteriorates due to heat over time (for example, heat received from direct sunlight in an automobile). This gives rise to the drawback that luster is produced and the grain pattern provided for giving a high-grade appearance disappears. That is, even if the obtained molded article is provided with a matte surface and / or a grain pattern in advance at the time of molding, its durability over time is poor and its surface state cannot be sufficiently maintained.

[0006] Under such circumstances, there is a strong demand for a modifier which can prevent the occurrence of gloss and maintain the grain pattern for a long period of time without lowering the moldability.

Therefore, in order to obtain a thermoplastic polyurethane powder slush molding material capable of preventing the occurrence of gloss of the skin material without deteriorating the moldability and maintaining the grain pattern for a long period of time, heat-resistant material which does not melt at the molding temperature is required. It has been found that searching for a resin powder is a current problem to be solved.

[0008]

Means for Solving the Problems As a result of intensive studies, the present inventors have blended a maleimide polymer fine particle powder having a particle size of 0.5 to 200 μm, which does not melt at a molding temperature, with a thermoplastic polyurethane powder resin composition. As a result, it has been found that the gloss of the skin material can be prevented, and the grain pattern can be maintained for a long period of time, and the present invention has been completed.

That is, the present invention relates to a resin composition for use in powder slush molding or the like, comprising a thermoplastic polyurethane resin powder as a main component, and a maleimide polymer fine particle powder having a particle size of 0.5 to 200 μm which does not melt at a molding temperature. And a compounding ratio of 0.5 to 5% by weight.

As the resin composition, those obtained by dry-blending the above-mentioned thermoplastic polyurethane resin powder and maleimide polymer fine particle powder together with a coloring pigment and other additives as necessary are preferably used. .

In the above resin composition, the maleimide polymer fine particle powder is contained in an amount of 0.5 to 5% by weight based on the thermoplastic polyurethane resin powder, and the maleimide polymer has a number average molecular weight of 2,2. 000-100,00
It is important that it is 0 or the like.

A resin molded product obtained by powder molding using the resin composition thus constituted as a raw material has a matte surface and has a good matting state holding durability. The present invention also relates to a molded article having a resin pattern as a raw material and having a grain pattern on the surface thereof, and selecting the composition as a molding material for a resin molded article having a matte surface. It is about.

[0013] Such a molded article has good durability of the grain pattern, and the matte surface of the grain pattern gives the molded article a sense of quality.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Typical and best modes of the embodiment of the present invention will be specifically shown in the following examples.
Each component that can be selected in implementing the present invention will be described in detail.

Specific examples of the maleimide polymer fine particles used in the present invention include N-methylmaleimide, N-ethylmaleimide, N-isopropylmaleimide, and Nn-n-maleimide.
Butylmaleimide, N-isobutylmaleimide, Nt
-Butylmaleimide, N-cyclohexylmaleimide,
N-2-ethylhexylmaleimide, N-decylmaleimide, N-dodecylmaleimide, N-octadecylmaleimide, N-cyclododecylmaleimide, N-phenylmaleimide, N-0-methylphenylmaleimide, N-
Examples thereof include those obtained by subjecting a maleimide compound such as benzylmaleimide, N-phenyl-2-chloromaleimide, or N-benzyl-2-methylmaleimide to a radical generator in an alcohol-based non-aqueous solvent and polymerizing the same.

The maleimide compound and another monomer having copolymerizability can be copolymerized within a range not exceeding 20% by weight.

When the amount of the other monomer exceeds 20% by weight, the heat resistance of the obtained maleimide polymer fine particle powder is impaired, which is not preferable.

Specific examples of other monomers include styrene monomers such as styrene and α-methylstyrene;
(Meth) acrylates such as methyl (meth) acrylate, butyl (meth) acrylate, β-hydroxyethyl (meth) acrylate, (meth) acrylonitrile, vinyl acetate, maleic anhydride, maleic acid, and fumaric acid And the like.

These maleimide polymer fine particles may be used singly or as a mixture of two or more. Among them, preferred are polymer fine particles of N-cyclohexylmaleimide and N-2-ethylhexylmaleimide, and copolymer fine particles of N-cyclohexylmaleimide and β-hydroxy-ethyl (meth) acrylate, and particularly preferred is polyurethane. It is a copolymer fine particle of N-cyclohexylmaleimide and β-hydroxy-ethyl (meth) acrylate because of its compatibility with the base resin powder.

The mixing ratio of the maleimide polymer fine particles is in the range of 0.5 to 5% by weight based on the thermoplastic polyurethane resin powder. Above all, the range of 1 to 2% by weight is particularly preferable from the viewpoint of preventing the gloss of the skin material from occurring and maintaining the grain pattern.

If the blending ratio of the maleimide polymer fine particles is less than 0.5% by weight, it is impossible to prevent the surface material from being glossy and to maintain a grain pattern. If it exceeds 5% by weight, the meltability of the thermoplastic polyurethane-based resin powder decreases, and the slush moldability deteriorates, which is not preferable.

The particle size of the maleimide polymer particles is as follows:
It is in the range of 0.5 to 200 μm. Above all, 100-15
The range of 0 μm is particularly preferable from the viewpoint of fluidity (powder flowability) of a resin composition mainly used for thermoplastic slush molding and used for powder slush molding.

The maleimide polymer fine particles have a particle size of 0.1.
If it is less than 5 μm, the fluidity (powder flowability) of the resin composition used for powder slush molding is impaired. 200μ
If it exceeds m, white spots are left on the surface of the skin material to cause poor appearance, gloss is not generated, and a grain pattern cannot be maintained, which is not preferable.

The shape of the fine particles is not particularly limited, but is preferably spherical or nearly spherical in view of the flowability of the material during molding.

The molecular weight of the maleimide polymer fine particles is in the range of 2,000 to 100,000 as the number average molecular weight. Above all, a range of 10,000 to 50,000 is particularly preferable from the viewpoint of heat resistance.

If the number average molecular weight of the maleimide polymer particles is less than 2,000, the particles are thermally melted at the temperature at the time of slush molding, and the gloss of the skin material cannot be prevented and the grain pattern cannot be maintained. If it exceeds 100,000, the meltability of the thermoplastic polyurethane-based resin powder decreases, and the slush moldability deteriorates, which is not preferable.

As examples of the maleimide polymer fine particles used in the present invention, those described in JP-A-3-246907 are considered to be effectively usable.

Specific examples of the thermoplastic polyurethane resin powder used in the present invention include those having a particle diameter of 30 to 40 ° C. which can be melted at 200 to 240 ° C., produced by a suspension polymerization method, a bulk polymerization method, or an emulsion polymerization method. Thermoplastic polyurethane resin powder in the range of 300 μm is exemplified.

In addition to the above-mentioned components, the slush molding powder resin composition of the present invention may further comprise a known material that is effective in preventing the gloss of the skin material and maintaining the grain pattern, which is an effect unique to the present invention. Conventional pigments, inorganic fillers, plasticizers, release agents, organic fillers, dispersants, ultraviolet absorbers (light stabilizers),
Antioxidants and the like can be added.

As a method of mixing the slush molding powder resin composition of the present invention, a method of dry blending using a high-speed rotary mixer is well known.

[0031]

The present invention will be described more specifically with reference to the following examples and comparative examples. In the examples, all parts are by weight unless otherwise specified.

Example 1 Thermoplastic polyurethane resin powder having a particle diameter in the range of 30 to 300 μm (manufactured by Dainippon Ink and Chemicals, Inc.) produced by a suspension polymerization method in a Henschel mixer having an internal volume of 10 l.
3 kg were charged, and 120 g of a blue pigment paste (50% pigment content) previously dispersed in a plasticizer (DIDP) and 15 g of zinc stearate as a release agent were dry-blended at a constant rotation speed. 20 with low speed stirring at 90-100 ° C
After cooling to a temperature of 40 ° C. or less by water cooling, the N-cyclohexylmaleimide polymer fine particle powder having a number average molecular weight of 15,000 and a particle diameter of 100 to 150 μm (manufactured by NOF CORPORATION; NOFLEX MP-200) ) 20 g was dry blended at a constant rotation speed to obtain a powder resin composition for slush molding.

Example 2 The number average molecular weight was 15,000, and the particle diameter was 100 to 150 μm.
Example 1 except that 15 g of N-cyclohexylmaleimide polymer fine particle powder (manufactured by NOF Corporation) was used.
In the same manner as in the above, a powder resin composition for slush molding was obtained.

Example 3 A maleimide polymer fine particle powder having a number average molecular weight of 20,000
00, 90 g of N-cyclohexylmaleimide having a particle diameter of 100 to 130 μm, and β-hydroxyethyl (meth)
Acrylate 10g copolymer fine particle powder (Nippon Oil & Fat)
A powder resin composition for slush molding was obtained in the same manner as in Example 1 except that 30 g of Noflex MP-10H (produced by K.K.) was used.

Example 4 100 g of a gray pigment paste (60% pigment content) previously dispersed in a plasticizer (DUP), a maleimide polymer fine particle powder having a number average molecular weight of 20,000 and a particle diameter of 100 to 1
90 g of 30 μm N-cyclohexylmaleimide, β
A powder resin composition for slush molding was obtained in the same manner as in Example 1, except that 60 g of copolymer fine particle powder of 10 g of hydroxyethyl (meth) acrylate was used.

Comparative Example 1 A thermoplastic polyurethane resin powder having a particle size in the range of 30 to 300 μm produced by a suspension polymerization method (Dainippon Ink Chemical Industry Co., Ltd.)
(Pandex) 3 kg, plasticizer (DI
DP) dispersed in a blue pigment paste (pigment content 50
%) And 15 g of zinc stearate as a release agent were dry-blended at a constant rotation speed. The mixture was allowed to stand at 90 to 100 ° C. for 20 minutes with low-speed stirring.
0) 3 g was dry-blended at a constant rotation speed to obtain a powder resin composition for slush molding.

Comparative Example 2 A slush molding powder resin composition was obtained in the same manner as in Comparative Example 1 except that 15 g of a benzoguanamine-based resin powder (Nippon Shokubai Kogyo KK; Eposter S) was used instead of silicon oxide. .

Comparative Example 3 Instead of silicon oxide, charcoal (Nitto Powder Co., Ltd .; N
S-200) A powder resin composition for slush molding was obtained in the same manner as in Comparative Example 1 except that 25 g was used.

Comparative Example 4 A thermoplastic polyurethane resin powder having a particle size in the range of 30 to 300 μm produced by a suspension polymerization method (Dainippon Ink Chemical Industry Co., Ltd.) was placed in a Henschel mixer having an internal volume of 10 l.
(Pandex) 3 kg, plasticizer (DI
DP) dispersed in a blue pigment paste (pigment content 50
%) And 15 g of zinc stearate as a release agent were dry-blended at a constant rotation speed. The mixture was allowed to stand at 90 to 100 ° C. for 20 minutes while stirring at a low speed, and then cooled to a temperature of 40 ° C. or less by water cooling to obtain a powder resin composition for slush molding.

Evaluation of performance Preparation of skin: A powdered resin composition for slush molding is charged into a Ni electroform having a grain pattern preheated to 230 ° C., and after leaving for 2 minutes, excess powdered resin composition is discharged. 23
After heating at 0 ° C. for further 30 seconds and cooling with water, it was peeled off from the Ni electroforming mold to form a skin material having a thickness of about 1 mm.

The performance was evaluated by the following test. Table 1 shows the results. (1) Fluidity (powder flowability): A glass bottle of 220 CC is half filled with powder and tilted at 45 °.
○ で Good △ ‥‥ Slightly insufficient fluidity × ‥‥ Block was observed and defective

(2) Meltability: The smoothness and gloss of the back surface of the skin material were visually observed and evaluated according to the following four grades. A: Both gloss and smoothness are sufficient. ○ ‥‥ There is smoothness but gloss is insufficient. △ ‥‥ There is luster, but lacks smoothness. × ‥‥ Completely glossy, rough surface.

(3) Heat resistance: The skin material was left for 100 hours in a gear oven type heating furnace (manufactured by Satake Rika Chemical Machinery Co., Ltd.) at 110 ° C., and the glossiness of the skin and the retention of the grain pattern were visually observed. And the following four grades. ◎ ‥‥ Almost no change in gloss or grain pattern was observed. ○ ‥‥ The gloss is slightly increased, but the grain pattern is hardly changed. △ ‥‥ The gloss is considerably increased, the surface of the skin material is melted, and the grain pattern is considerably disappeared. × ‥‥ The skin material has melted and the grain pattern has completely disappeared.

The maleimide polymer fine particle powder of the present invention comprises:
It is useful as a thermoplastic polyurethane-based slush molding material because it prevents the matte skin material from producing gloss over time without impairing the meltability of the composition at the time of molding and can retain a grain pattern.

[0045]

[Table 1]

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location B29K 75:00

Claims (6)

[Claims] 1. A resin composition mainly composed of a thermoplastic polyurethane resin powder for use in powder slush molding or the like, which has a particle size of 0.5 to 200 which does not melt at a molding temperature.
A resin composition for powder molding, comprising a maleimide polymer fine particle powder having a particle size of μm. 2. The method according to claim 1, wherein the thermoplastic polyurethane resin powder and the maleimide polymer fine particle powder are dry-blended together with a coloring pigment and other additives which are added as required. The described resin composition. 3. The resin composition according to claim 1, wherein the maleimide polymer fine particle powder is contained in an amount of 0.5 to 5% by weight based on the thermoplastic polyurethane resin powder. 4. The method according to claim 1, wherein the maleimide polymer has a number average molecular weight of 2,000 to 100,000 and does not melt at a molding temperature. Resin composition. 5. The resin composition according to claim 1, which is used for molding a molded article having a matte surface. 6. A resin molded article which is made of the resin composition according to any one of claims 1 to 4 and has a matte pattern on its surface and is matte.