JP2003192836A - Powder molding resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a powder molding resin composition which can easily be produced and can be subjected to a powder molding processing to give the molded article that has excellent creasing resistance when demolded, and further has improved heat resistance and abrasion resistance. <P>SOLUTION: This powder molding resin composition comprises (1) 20 to 80 pts.wt. of a polypropylene resin composition comprising (a) 20 to 80 wt.% of polypropylene resin and (b) 80 to 20 wt.% of an olefinic thermoplastic elastomer, (2) an aromatic vinyl compound-conjugated diene copolymer hydrogenation product in an amount of 80 to 20 pts.wt. [the total amount of (1) and (2) is 100 pts.wt.], and (3) a fatty acid amide in an amount of 1 to 20 pts.wt. per 100 pts.wt. of the total amount of (1) and (2). <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a resin composition for powder molding, and more specifically, it provides a molded article excellent in heat resistance, crease resistance and abrasion resistance at room temperature and high temperature. The present invention relates to a resin composition for easy powder molding.

[0002]

2. Description of the Related Art As a skin material for interior parts such as an instrument panel, a console box, a door trim and a glove box of an automobile, a soft vinyl chloride resin molded product has been used. However, recently, a molded product made of a resin which does not generate hydrogen chloride at the time of incineration of waste products and which is made of an olefin resin material which can be easily recycled is desired. Therefore, many olefin resin compositions have been proposed as powder molding materials (for example, JP-A-5-1183, JP-A-5-5050, JP-A-6-170871, and JP-A-6-). 22
6763, Japanese Patent Laid-Open No. 7-178742, Japanese Patent Laid-Open No. 8-217927, etc.). However, according to these, molded products generally have poor light resistance, and are not as flexible as conventional soft vinyl chloride resins, and when a softening agent is added, there is a problem that bleeding occurs on the surface of the molded product and it becomes sticky. .

As a result of studying to solve the above problems, the present applicant has found that S of styrene and butadiene having a bound styrene content of 20 to 50% by weight and a number average molecular weight in a specific range.
BS type block copolymer (S: polystyrene block,
B: polybutadiene block) hydride (SEBS)
It has been found that a composition containing a is suitable as a powder molding material such as a skin of an interior material of an automobile (Japanese Patent Laid-Open No. 5-279).
No. 484). Furthermore, in order to improve the heat resistance of the molded product using the above hydride, polypropylene resin (P
P) (Japanese Patent Application Laid-Open No. 7-82433),
Further, a method of blending a polyolefin (Japanese Patent Laid-Open No. 2000-
336219) and the like have been proposed.

However, since PP has low compatibility with SEBS, it has poor processability, and it is difficult to obtain a composition in which both are uniformly mixed, and slush molding is caused by the high crystallinity of PP. However, there is a problem that the molded product is likely to be wrinkled when the mold is removed. Further, the skin resistance of the molded product immediately after slush molding was not sufficient with respect to the wear resistance at a high temperature of about 60 to 70 ° C., and it was necessary to improve it.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to facilitate production and to provide excellent crease resistance during demolding in powder molding. It is an object of the present invention to provide a resin composition for powder molding, which enables powder molding of a molded body having improved heat resistance and abrasion resistance at room temperature and high temperature. The present inventors have studied to achieve the above objects, the polypropylene resin composition comprising a polypropylene resin and an olefinic thermoplastic elastomer has improved compatibility with SEBS, and creases during mold release are less likely to occur. By adding oleic acid amide to this resin composition, it was found that the obtained powder compact has excellent wear resistance at room temperature and high temperature, and the present invention was completed based on this finding. It was

[0006]

Thus, according to the present invention, (1) (a) 20 to 80% by weight of polypropylene resin and (b) olefinic thermoplastic elastomer 80 to 2 are used.
Polypropylene resin composition 20 to 8 consisting of 0% by weight
0 parts by weight and (2) 80 to 20 parts by weight of a hydride of an aromatic vinyl compound-conjugated diene copolymer ((1) and (2)
Is 100 parts by weight. ), And (3) fatty acid amide in an amount of 1 to 2 relative to 100 parts by weight of the total of (1) and (2).
A resin composition for powder molding containing 0 part by weight is provided.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below.
The polypropylene resin composition (1) used in the present invention is
(A) Polypropylene resin 20 to 80% by weight, preferably 30 to 70% by weight, and (b) olefinic thermoplastic elastomer 80 to 20% by weight, preferably 70 to 30% by weight (provided that (a) and (b The total of) is 100% by weight.). If the polypropylene resin is too small, the heat resistance will decrease, and if it is too large, creases are likely to occur during demolding, which is not preferable.

The ratio of the polypropylene resin composition (1) to the hydride (2) of the aromatic vinyl compound-conjugated diene copolymer is such that (1) is 20 to 80 parts by weight, preferably 30 to 70 parts by weight. Parts, (2) is 80 to 20 parts by weight, preferably 70 to 30 parts by weight (however, the sum of (1) and (2) is 100 parts by weight). If the polypropylene resin composition (1) is too small, the meltability will decrease, and if it is too large, creases will easily occur and the scratch resistance of the molded product will decrease, such being undesirable.

The polypropylene resin used in the present invention is
Propylene homopolymer (crystalline) or propylene 50
It is a copolymer of at least wt% and another α-olefin having 2 to 12 carbon atoms. Here, propylene and C2-12
The copolymers with α-olefins include random copolymers, alternating copolymers, and linear and radial block copolymers. These polypropylene resins are usually produced by polymerizing using a Ziegler-Natta catalyst or the like. Examples of the α-olefin include ethylene, butene-1, 4-methyl-pentene-1, octene-1 and the like. The melt flow rate (hereinafter referred to as MFR) of the polypropylene resin is not particularly limited, but one having an MFR according to JLS K7210 (load 2.16 kg, measurement temperature 230 ° C., unit is g / 10 min.) Is 5 or more. It is preferable that the MFR is 20 or more. If the MFR of the polypropylene resin is too small, the meltability is poor and pinholes may easily occur in the molded product, which is not preferable.

The olefinic thermoplastic elastomer used in the present invention is usually called TPO or TPE, in which polyolefin such as polyethylene or polypropylene is used for the hard segment and polyolefin rubber such as ethylene-propylene rubber is used for the soft segment. Thus, for example, a blend of EPR (ethylene-propylene copolymer rubber) or EPDM (ethylene-propylene-non-conjugated diene monomer terpolymer rubber) with PP or PP / PE (polyethylene), or the above blend with PP or EPDM is incorporated into a matrix phase such as PP by so-called dynamic crosslinking, which cross-links EPDM and the like while melting PP / PE.
Etc. (elastomer alloy), referred to as Reactor TPO, which has a large amount of ethylene / propylene copolymer (EPR) block portion obtained by copolymerizing propylene and ethylene after polymerization of PP. Examples include block copolymers. These are all commercially available products and are available.
Above all, propylene block copolymer (Reactor T
PO) is preferable, and P.P. manufactured by Tokuyama Corporation is used. E. R. Is marketed as.

The ratio of the ethylene / propylene copolymer block component (EPR component) and the polypropylene block component (PP component) of the propylene block copolymer (reactor TPO) is 1 to 40% by weight, preferably PP component. 5 to 20% by weight, and EPR component is 60 to 9
It is 9% by weight, preferably 80 to 95% by weight. Also,
The EPR component is composed of a random copolymer of ethylene and propylene, and the proportion of monomer units based on ethylene is usually 10 to 40 mol%, preferably 15 to 35 mol%. Further, the propylene-based block copolymer has a molecular weight of 6 to 30 dl / g as an intrinsic viscosity measured in a tetralin solvent at 135 ° C., preferably 10 to 20 d.
1 / g. If the intrinsic viscosity of the propylene-based block copolymer is less than 6 dl / g, the recoverability after elastic deformation is impaired, and if it exceeds 30 dl / g, the fluidity at the time of melting is lowered, and powder molding becomes extremely difficult.

Aromatic vinyl compound used in the present invention
As the hydride of the conjugated diene copolymer, styrene, α
-Random copolymer obtained by random or block copolymerization of at least one aromatic vinyl compound such as methylstyrene and vinyltoluene and at least one conjugated diene such as butadiene, isoprene and 1,3-pentadiene Alternatively, it is obtained by hydrogenating the conjugated diene unit of the block copolymer. Of these, hydrogenated block copolymers are preferable.

The above random copolymer is a styrene-butadiene copolymer rubber (SBR), and the block copolymer is an ABA type linear and radial block copolymer (A is a polystyrene block, B is a polybutadiene block or polyisoprene). Blocks) are preferred. The hydrogenated block copolymers described above are SEBS, SEPS (S: polystyrene, E:
Polyethylene, B: polybutylene, P: polypropylene) are commonly called. These hydrides are usually
80 mol% or more, preferably 90 mol% or more, more preferably 95 mol% or more of the unsaturated double bonds in the polymer chain are hydrogenated. The content of the aromatic vinyl compound unit in the hydride of the aromatic vinyl compound-conjugated diene copolymer (hereinafter, sometimes referred to as the amount of bonded aromatic vinyl compound) is usually 5 to 50% by weight, Preferably 10
~ 30% by weight. If the amount of bound aromatic vinyl is too small, blocking tends to occur during powder molding, which is not preferable. If it is too large, the hardness of the molded product increases, which is not preferable.

A fatty acid amide is further added to the powder molding resin composition of the present invention. The fatty acid amide used in the present invention is not particularly limited, but usually has 7 carbon atoms.
Examples thereof include primary fatty acid amides and bis fatty acid amides that are derivatives of the above higher fatty acids. The higher fatty acids include saturated fatty acids and unsaturated fatty acids. Examples of saturated higher fatty acids include caprylic acid, lauric acid, tridecyl acid, pentadecyl acid, palmitic acid, stearic acid,
Examples include arachidic acid and lignoceric acid. Examples of unsaturated fatty acids include undecyl acid, oleic acid,
Examples thereof include elaidic acid, sorbic acid and linoleic acid.

Specific examples of the fatty acid amide include, for example,
Stearoamide, oleioamide, palmitoamide, coconut oil fatty acid amide, methylenebis-stearoamide, ethylenebis-stearoamide, ethylenediamine of oxystearic acid and the like can be mentioned. These can be used alone or in combination of two or more. As the fatty acid amide, unsaturated fatty acid amide is preferable, and oleioamide is particularly preferable.

The fatty acid amide is added to 100 parts by weight of the polypropylene resin composition (1) and the hydride (2) of the aromatic vinyl compound-conjugated diene copolymer.
It is added in a proportion of 1 to 20 parts by weight. If the amount of the fatty acid amide added is too small, the wear resistance of the molded product at high temperatures (about 60 ° C.) may decrease, and if it is too large, bleeding easily occurs on the surface of the molded product. When it is used for interior parts such as for instrument panels for automobiles, the adhesion with the polyurethane foam may be reduced.

If desired, various additives can be added to the resin composition of the present invention. For example, barium stearate, calcium stearate, in order to improve mold release during molding and prevent blocking during storage.
Metal soaps such as magnesium stearate, zinc stearate, and aluminum stearate, and fatty acid esters of polyhydric alcohols can be added. As other additives, various known stabilizers, antioxidants, ultraviolet absorbers, antistatic agents, flame retardants, pigments and the like can be added. Further, a known plasticizer may be added within a range that does not cause stickiness or impair the moldability.

Further, a polymer other than the above-mentioned polymer components may be used in combination within the range not impairing the gist of the present invention. Examples of such a polymer include acrylonitrile-butadiene-styrene resin (ABS resin), acrylonitrile-styrene resin (AS resin), ethylene-vinyl acetate resin (EVA resin), norbornene resin, polyamide resin, polyester resin. Resin, polycarbonate resin, polybutadiene resin and the like can be mentioned.
Further, an aromatic vinyl compound-α-olefin copolymer obtained by copolymerizing an aromatic vinyl compound such as styrene and an α-olefin such as ethylene or propylene (Japanese Patent Laid-Open No. 7705/1993, Japanese Patent Laid-Open No. 70223
Japanese Patent Laid-Open No. 10-168112, etc.). The amount of these other polymers used is in the range of 40% by weight or less, preferably 30% by weight or less in the resin composition of the present invention.

The method for producing the powder molding resin composition of the present invention is not particularly limited. Further, the form or shape of each polymer component used is not particularly limited. As a manufacturing method, for example, the component (1) and the component (2) are put into a mixer all at once and mixed, and then mixed with a fatty acid amide. First, a polypropylene resin composition is rolled,
Prepared using a normal mixer such as a single-screw or twin-screw extruder, a Banbury mixer, a kneader, etc., and this is mixed with an aromatic vinyl compound-hydride of a conjugated diene copolymer in the same manner as above, and further Method for producing by mixing with fatty acid amide, polypropylene resin composition and aromatic hydride of vinyl compound-conjugated diene copolymer are mixed, and then pulverized, and then fatty acid amide is added to obtain powder state And the method of mixing.

The resin composition for powder molding of the present invention is used in powder form. In order to make a powder, it is necessary to adjust a powdery resin composition having excellent powder fluidity by pulverizing with a conventionally known pulverizer such as a turbo mill, a roller mill, a ball mill, a centrifugal pulverizer, and a pulverizer. You can The particle size of the powder is usually in the range of 50 to 500 μm, preferably 100 to 300 μm. If this average particle size is too small, the efficiency of the crushing process is poor and it tends to agglomerate during storage. Conversely, if it is too large, the texture of the molded product will become rough, and pinholes will occur in the case of thin molded products. It is not preferable because it is easy to

The powdery resin composition for powder molding of the present invention as described above can be applied to various powder molding methods such as powder slush molding, fluidized dip molding and powder rotational molding. It can be suitably used as a powder molding material for the surface layer of automobile interior parts such as headrests, console boxes, door trims and armrests.

[0022]

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples. The number of parts and% are based on weight unless otherwise specified. The test method is as follows.

(1) Folding wrinkle resistance Resin composition powder for powder molding is slush molded,
The sheet-shaped molded product (thickness is about 1 mm) is released from the mold without folding creases left, and a test piece of 15 × 50 mm is cut out. This test piece is bent 180 degrees in a room at 23 ° C., placed on a horizontal surface in that state, placed with a weight of 1 kg for 10 seconds and then removed, and after the shape is sufficiently recovered, the angle between the horizontal surface and the folded sheet is measured. Similarly 65
Carry out at ° C. The smaller the value, the better the crease resistance.

(2) Abrasion resistance A 30 × 80 mm test piece cut out in the same manner as in (1) was placed on a table on which it can reciprocate, and a width of 20
mm steel friction element (4 pieces of gold width 3 stacked and covered) is placed on the test piece, and a load of 2.5 kgf is applied to the test piece, and the surface of the test piece is reciprocated 5 times at a speed of 60 cycles / minute. Then, the degree of whitening of the surface of the test piece at that time was observed. The display of the results is as follows. ○: No whitening △: Slightly whitening ×: Whitening

(3) Heat resistance A 150 × 100 mm test piece cut in the same manner as in (1) is left in an oven at 120 ° C. for 100 hours. After that, the test piece taken out was left at room temperature for 1 hour, and the degree of stickiness on the surface was evaluated with a tentacle. The display of the results is as follows. ○: The surface is not sticky ×: The surface is sticky

Examples 1 to 7 and Comparative Examples 1 to 2 The components of the types and amounts shown in Table 1 were kneaded by a twin-screw extruder (TEM35B manufactured by Toshiba Machine Co., Ltd.), pelletized, and then in a turbo mill. The powder was pulverized to obtain a powdery resin composition for powder molding. Using the obtained powdery resin composition,
The meltability test by slush molding was performed, and the obtained sheet was used to evaluate folding wrinkle resistance, abrasion resistance, and heat resistance. The results are shown in Table 1.

[0027] (Note) (1) Sun Allomer PM940M (MFR
30) (2) Same as above Sun Attack (Atactic PP) (3) Tokuyama P.P. E. R. M142E (Reactor TPO) (4) Asahi Kasei Corporation Tuftec H1221 (bound styrene content 12%) (5) Ethylenebisstearic acid amide (6) Ethylenebisbehenic acid amide (7) Mitsubishi Chemical Corporation

From Table 1, polypropylene resin composition and S
When mixed with EBS and further blended with fatty acid amide (Examples 1 to 7), since the bending angle was small, the crease resistance was good, and the balance between abrasion resistance and heat resistance was good. I know there is. On the other hand, when the fatty acid amide is not blended (Comparative Example 1), the abrasion resistance is not improved, and when the olefinic thermoplastic elastomer is not blended (Comparative Example 2), the crease resistance is inferior. I understand.

[0029]

EFFECTS OF THE INVENTION According to the present invention, a resin composition for powder molding is provided, which is easy to manufacture and can obtain a powder molded article excellent in crease resistance, heat resistance, abrasion resistance and the like.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Satoshi Iwabuchi             1-2-1 Yokou, Kawasaki-ku, Kawasaki-shi, Kanagawa             ON Kasei Co., Ltd. Kawasaki Laboratory (72) Inventor Koichi Yanai             1-2-1 Yokou, Kawasaki-ku, Kawasaki-shi, Kanagawa             ON Kasei Co., Ltd. Kawasaki Laboratory (72) Inventor Toshiya Kobayashi             1-2-1 Yokou, Kawasaki-ku, Kawasaki-shi, Kanagawa             ON Kasei Co., Ltd. Kawasaki Laboratory F-term (reference) 4J002 AC11W BB03X BB12X BB12Y                       BB14Y BB15X BP01W EP016                       EP026 FD160 FD20X FD206                       GN00 HA09

Claims (4)

[Claims] (1) (a) Polypropylene resin 20 to
20 to 80 parts by weight of a polypropylene resin composition comprising 80% by weight and (b) 80 to 20% by weight of an olefinic thermoplastic elastomer, and (2) an aromatic vinyl compound-
80 to 20 parts by weight of a hydride of the conjugated diene copolymer (the total of (1) and (2) is 100 parts by weight),
(3) A powder molding resin composition containing 1 to 20 parts by weight of fatty acid amide per 100 parts by weight of the total of (1) and (2). 2. An olefinic thermoplastic elastomer,
The resin composition for powder molding according to claim 1, which is a propylene-based block copolymer. 3. The powder according to claim 1, wherein the hydride of the copolymer of an aromatic vinyl compound and a conjugated diene is a hydride of a block copolymer of an aromatic vinyl compound and a conjugated diene. Molding resin composition. 4. The resin composition for powder molding according to claim 1, wherein the fatty acid amide is an unsaturated fatty acid amide.