JP2001115010A - Thermoplastic polyurethane resin composition for powder molding and molding material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain both a thermoplastic polyurethane resin composition having excellent slash moldability, mold release characteristics during powder molding of molding product and bleedout resistance and a molding material, especially a molding material for an interior automotive trim. SOLUTION: This thermoplastic polyurethane resin composition for powder molding characteristically comprises a thermoplastic polyurethane resin (A) and a mixed ester compound (B) obtained by reacting a polyhydric alcohol with a dibasic acid and a higher fatty acid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic polyurethane resin composition which is excellent in slush moldability, mold release property during powder molding of molded articles, and bleed-out resistance, and molding materials, especially for automobile interior materials. It is to provide a suitable molding material.

[0002]

2. Description of the Related Art Conventionally, polyvinyl chloride-based powder resins have been used for slush molding methods for skin materials for automobile interiors (instrument panels, glowing boxes, headrests, etc.).

However, polyvinyl chloride has problems such as environmental problems such as acid rain caused by chlorine, fogging property (volatilization of plasticizer at high temperature), and insufficient texture.
Recently, thermoplastic polyurethane resins have been receiving attention as a substitute for polyvinyl chloride for these applications.

Heretofore, as a method for producing a thermoplastic polyurethane resin for powder molding, a thermoplastic polyurethane resin for powder molding having a constant average particle size under a dispersant and a solvent during polymerization is produced by a method such as solution polymerization. Methods (JP-A-63-75038, JP-A-2-4860, JP-A-2-38453) and the like are disclosed.

The fluidity and blocking resistance of a thermoplastic polyurethane resin for powder molding are improved by adding a silica aerosol (JP-A-6-4141).
No. 9) is disclosed. However, the thermoplastic polyurethane resins for powder molding described in these publications mainly describe a manufacturing method for obtaining a powder material and fluidity of the powder resin, and are used for powder molding such as actual powder slush molding. There is no disclosure about the releasability of the important thermoplastic polyurethane resin for powder molding from a mold.

Further, when a commonly used release agent such as silicone is internally or externally added, a certain release property can be obtained, but lacks compatibility with the thermoplastic polyurethane resin. There are drawbacks such as the phenomenon of bleeding out on the surface over time and contamination of the molded product surface.

The thermoplastic polyurethane resin has more excellent properties such as mechanical strength, texture, and transferability of grain of the obtained skin material than polyvinyl chloride used for this purpose. However, when the thermoplastic polyurethane resin for powder molding is filled into the details of the mold at the time of slush molding and the mold is released from the mold, the adhesiveness of the thermoplastic polyurethane resin is large and the mold collapses at the time of mold release. There was a problem of doing it.

When a commonly used release agent such as silicone or the like is added or preliminarily applied to a mold, a certain release property can be obtained, but the compatibility with the thermoplastic polyurethane resin is lacking. Therefore, there is a disadvantage that a phenomenon of bleeding out on the surface occurs over time.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a thermoplastic polyurethane resin composition which is excellent in slush moldability, mold release property in molding powder of molded articles, and bleed-out resistance, and molding materials, especially automobiles. In molding materials for interior materials.

[0010]

Means for Solving the Problems The present inventors have conducted intensive studies on a method for improving the above-mentioned problems without impairing the excellent performance of the thermoplastic polyurethane resin. It has been found that by mixing a mixed ester compound obtained by reacting a basic acid and a higher fatty acid, the mold releasability of a powder is remarkably improved, and the present invention has been completed.

That is, the present invention provides a thermoplastic polyurethane for powder molding, comprising a thermoplastic polyurethane resin (A), a mixed ester compound obtained by reacting a polyhydric alcohol, a dibasic acid and a higher fatty acid (B). Resin composition, preferably 100 parts by weight of component (A), component (B) 0.1
The present invention provides a thermoplastic polyurethane resin composition for powder molding and a molding material, wherein the thermoplastic polyurethane resin (A) has an average particle diameter of 800 µm or less, which is blended in an amount of from 5 to 5 parts by weight. .

[0012]

DETAILED DESCRIPTION OF THE INVENTION The thermoplastic polyurethane resin (A) of the present invention is preferably an organic diisocyanate (I) and a dihydroxy compound (I) having an average molecular weight of 500 to 4000.
I) and a dihydroxy compound having a molecular weight of less than 500 (II
I) and the reaction ratio (I) / ((II) + (III)), 0.9
~ 1.1.

The thermoplastic polyurethane resin (A) of the present invention
Is produced by polymerizing an organic diisocyanate (I), a dihydroxy compound (II) having a number average molecular weight of 500 to 4,000 and a dihydroxy compound (III) having a molecular weight of less than 500 in the presence of a dispersant and a solvent. For obtaining thermoplastic polyurethane resin for powder molding having a certain average particle size from organic diisocyanate (I)
And a mixture of the dihydroxy compound (II) and the dihydroxy compound (III) previously uniformly mixed with high-speed stirring and cast on a vat subjected to a mold release treatment, and if necessary, reacted at a temperature of 200 ° C. or lower. To be manufactured or
Organic diisocyanate (I) and dihydroxy compound (I
I) to give a prepolymer having terminal isocyanate groups, and then a dihydroxy compound (III) is added, mixed with high-speed stirring, cast onto a vat subjected to a mold release treatment, and if necessary, a temperature of 200 ° C. or lower. There is a method of producing by reacting with. In this order, a batch reaction method, a continuous reaction method, and an extruder can be used for production.

At this time, the reaction ratio of the organic diisocyanate (I) with the dihydroxy compounds (II) and (III) (I) /
((II) + (III)) is preferably 0.9 to 1.1,
More preferably, it is 0.95 to 1.05. If the reaction ratio is less than 0.9 or greater than 1.1, the molecular weight does not increase sufficiently and the required physical properties cannot be obtained.

As the organic diisocyanate (I), any known organic diisocyanate can be used. For example, hexamethylene diisocyanate, lysine diisocyanate,
Isophorone diisocyanate, xylene diisocyanate, cyclohexane diisocyanate, toluidine diisocyanate, 2,4-tolylene diisocyanate,
2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, p-phenylene diisocyanate, m-phenylene diisocyanate, 1,5-
Naphthylene diisocyanate and mixtures thereof can be used.

Preferred examples of the dihydroxy compound (II) having a number average molecular weight of 500 to 4000 include polyester diol, polyether diol, polycarbonate diol and the like.

Examples of the polyester diol include ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 3-methyl-1,
5-pentanediol, cyclohexanedimethanol,
Or condensation of one or more other low molecular weight diol components with one or more dibasic acids such as adipic acid, azelaic acid, glutaric acid, suberic acid, sebacic acid, terephthalic acid, and isophthalic acid Polylactone diols obtained by ring-opening polymerization of polymers and lactones, for example, polypropiolactone diol, polycaprolactone diol, polyvalerolactone diol, and the like.

Examples of the polyether diol include polypropylene ether glycol, polytetramethylene ether glycol, polyhexamethylene ether glycol, and other copolymerized polyether glycols.

Polycarbonate diols include polyhexamethylene carbonate diol, diols obtained by ring-opening addition polymerization of lactone to polyhexamethylene carbonate diol, polyhexamethylene carbonate diol and other polyester diols, polyether diols, polyethers. Co-condensates with ester diols and the like can be mentioned.

The dihydroxy compound (III) having a molecular weight of less than 500 includes, for example, ethylene glycol,
1,2-propylene glycol, 1,3-propylene glycol, 2,3-butylene glycol, 1,4-butanediol, 2,2′-dimethyl-1,3-propanediol, diethylene glycol, 1,5-pentanediol , 1,6-hexanediol, cyclohexane-
One or a mixture of 1,4-diol, cyclohexane-1,4-dimethanol and the like can be mentioned.

As a commercial product of the thermoplastic polyurethane resin of the present invention, Pandex series (product of Dainippon Ink and Chemicals, Inc.) can be used. For example, TR-308
0, T-7890 and the like can be preferably used.

As a method for pulverizing the obtained thermoplastic polyurethane resin, freeze pulverization is carried out at a temperature below the brittle point,
A method of obtaining a thermoplastic polyurethane resin for powder molding having a desired particle size by sieving, or a method of obtaining a powdery thermoplastic polyurethane resin using a die having a hole diameter of 500 μm or less using an extruder And so on.

The average particle size of the thermoplastic polyurethane resin for powder molding used in the present invention is preferably 800 μm or less, more preferably 50 to 500 μm, in order to obtain a slush molded sheet having a uniform film thickness.

The mixed ester compound (B) obtained by reacting a polyhydric alcohol, a dibasic acid and a higher fatty acid with the thermoplastic polyurethane resin (A) is preferably a polyhydric alcohol.
The molar ratio of (B1), dibasic acid (B2) and higher fatty acid (B3) is (B
1): (B2): (B3) = 1 to 2: 2 to 2: 2 to 10

Examples of the polyhydric alcohol of the mixed ester compound (B) used in the present invention include pentaerythritol, dipentaerythritol, glycerin, trimethylolpropane and the like. Further, as the dibasic acid, for example, adipic acid, azelaic acid, glutaric acid,
Suberic acid, sebacic acid, terephthalic acid, isophthalic acid, and the like. Examples of higher fatty acids include, for example, saturated higher fatty acids such as lauric acid, palmitic acid, and stearic acid, and oleic acid, linoleic acid, linolenic acid, and ricinoleic acid. And higher unsaturated fatty acids.

Here, the compounding amount of the mixed ester compound (B) obtained by reacting the polyhydric alcohol, the dibasic acid and the higher fatty acid with respect to 100 parts by weight of the thermoplastic polyurethane resin is 0.1%.
It is preferably from 5 to 5 parts by weight, more preferably from 0.1 to 1 part by weight. When the amount is less than 0.1 part by weight, the releasability from the mold is not improved, and when the amount exceeds 5 parts by weight, the dispersibility in the thermoplastic polyurethane resin is deteriorated,
It causes bleed out after molding and poor adhesion to the substrate.

In the present invention, in order to obtain an excellent mold releasing property of the thermoplastic polyurethane resin for powder molding, it is necessary to mix a mixed ester (B) obtained by reacting a polyhydric alcohol, a dibasic acid and a higher fatty acid. It is important that the amount added is within the above-mentioned fixed range.

In the present invention, the mixed ester compound (B)
The mixing method of thermoplastic polyurethane resin
There is a method in which (A) is mixed with a polyol at the time of production, or a method in which a thermoplastic polyurethane resin is powdered and then mixed in a subsequent step using a high-speed stirring mixer such as a Henschel mixer or a tumbler. The resin composition according to the present invention is a coating or impregnated thermoplastic polyurethane resin (A) powder resin containing the ester compound (B).

In order to use the thermoplastic polyurethane resin composition of the present invention as a molding material, an antioxidant, an ultraviolet absorber, an antistatic agent, an organic plasticizer, a filler,
Other thermoplastic resins and pigments, processing aids, lubricants, and the like are used by adding known ones.

The powder molding referred to in the present invention is a fluid immersion method,
Examples include an electrostatic coating method, a powder spraying method, a powder rotational molding method, and a powder slash molding method. In particular, a powder rotational molding method or a powder slush molding method is preferred for use as a covering material for automotive interior materials.

[0031]

Next, the present invention will be described by way of examples, but this is only one mode, and the present invention is not limited only to the examples. In addition, all “parts” in the text indicate weight standards.

(Example of Preparation of Thermoplastic Polyurethane Resin Composition for Powder Molding) (Example 1) Thermoplastic polyurethane (PANDEX TR)
-3080; manufactured by Dainippon Ink and Chemicals, Inc.), and powder (A) having an average particle size of 50 to 500 μm obtained by freeze-pulverization.
Polycondensate obtained by reacting 100 parts by weight of dipentaerythritol / adipic acid / oleic acid at a molar ratio of 2/8/1
0.5 parts by weight (referred to as B and b) were added, and the mixture was stirred and mixed for 30 seconds using a high-speed stirring mixer (Henschel mixer) to obtain a uniform thermoplastic polyurethane resin composition for powder molding. The obtained thermoplastic polyurethane resin composition for powder molding was evaluated by the following method.

(Evaluation Method of Thermoplastic Polyurethane Resin Composition for Powder Molding) A slush moldable electroforming mold (200 mm × 300 mm × 10 mm) was heated to a mold temperature of 230 to 240 ° C. The thermoplastic polyurethane resin composition for use is charged and excess powder is removed from the mold. The powder is leveled so as to have a thickness of 0.5 mm, and is forcibly cooled with pressurized air to obtain a molded sheet. The surface properties and uniform film thickness of the obtained sheet were evaluated.

(Evaluation Criteria) 非常: A very uniform sheet was obtained. Δ: Partially non-uniform part was obtained. X: A uniform sheet could not be formed.

Releasability from Mold The releasability of the molded sheet obtained from the slush molding test from the mold was evaluated. (Evaluation Criteria) ：: Easy release without stickiness. Δ: Adhesion with the mold was slightly observed during release. X: It is difficult to release from the mold.

Bleed-out of molded product The sheet obtained by the slush molding was left in a dryer at 80 ° C for 16 hours. After the removal, the bleed-out state on the surface of the molded sheet was observed. (Evaluation criteria) ○: No bleed-out ×: Bleed-out Table 1 shows the evaluation results.

Example 2 A polycondensate obtained by reacting 100 parts of a thermoplastic polyurethane powder (A) with dipentaerythritol / adipic acid / oleic acid in a molar ratio of 2/1/8 in the same manner as in Example 1 B and b) to obtain a thermoplastic polyurethane resin composition for powder molding. Table 1 shows the evaluation results of the obtained thermoplastic polyurethane resin compositions for powder molding.

(Example 3) A polycondensate obtained by reacting 100 parts of a thermoplastic polyurethane powder (A) with dipentaerythritol / adipic acid / oleic acid in a molar ratio of 2/1/8 in the same manner as in Example 1 B, b) were mixed to obtain a thermoplastic polyurethane resin composition for powder molding. Table 1 shows the evaluation results of the obtained thermoplastic polyurethane resin compositions for powder molding.

Example 4 A polycondensate (B) obtained by reacting 100 parts of a thermoplastic polyurethane powder (A) with pentaerythritol / adipic acid / oleic acid in a molar ratio of 2/1/4 in the same manner as in Example 1 , C) were mixed to obtain a thermoplastic polyurethane resin composition for powder molding. Table 1 shows the evaluation results of the obtained thermoplastic polyurethane resin compositions for powder molding.

COMPARATIVE EXAMPLE 1 A thermoplastic polyurethane was freeze-pulverized in the same manner as in Example 1 to obtain a thermoplastic polyurethane resin composition (A) for powder molding of 50 to 500 μm. Table 1 shows the evaluation results of the obtained thermoplastic polyurethane resin compositions for powder molding.

Comparative Example 2 A polycondensate obtained by reacting 100 parts of a thermoplastic polyurethane powder (A) with dipentaerythritol / adipic acid / oleic acid in a molar ratio of 2/1/8 in the same manner as in Example 1 B, b) were mixed to obtain a thermoplastic polyurethane resin composition for powder molding.
Table 1 shows the evaluation results of the obtained thermoplastic polyurethane resin compositions for powder molding.

Comparative Example 3 In the same manner as in Example 1, 100 parts of a thermoplastic polyurethane powder (A) was mixed with 1 part of dimethylpolysiloxane (SH-200; manufactured by Toray Dow Corning KK) (referred to as d). Thus, a thermoplastic polyurethane resin composition for powder molding was obtained. Table 1 shows the evaluation results of the obtained thermoplastic polyurethane resin compositions for powder molding.

[0043]

[Table 1]

[0044]

Industrial Applicability The thermoplastic polyurethane resin composition for powder molding of the present invention is excellent in slush moldability, mold releasability during powder molding of molded products, and bleed-out resistance, and is used as a molding material, especially for automobile interior materials. It is suitable for.

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Claims (4)

[Claims] 1. A thermoplastic polyurethane resin composition for powder molding, comprising a mixed ester compound (B) obtained by reacting a thermoplastic polyurethane resin (A), a polyhydric alcohol, a dibasic acid and a higher fatty acid. 2. A thermoplastic polyurethane resin (A) 100
2. The thermoplastic polyurethane resin for powder molding according to claim 1, wherein 0.1 to 5 parts by weight of a mixed ester compound (B) obtained by reacting a polyhydric alcohol, a dibasic acid and a higher fatty acid is blended with respect to parts by weight. Composition. 3. The thermoplastic polyurethane resin composition for powder molding according to claim 1, wherein the average particle size of the thermoplastic polyurethane resin (A) is 800 μm or less. 4. A molding material comprising the thermoplastic polyurethane resin composition for powder molding according to claim 1 as a main component.