JPH1045971A - Polypropylene resin composition for automotive interior material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polypropylene resin compsn. for automotive interior materials excellent in softness and resistances to scratch and whitening. SOLUTION: This compsn. comprises a polypropylene resin (A), talc (B), and an ethylene-α-olefin copolymer elastomer (C) in wt. ratios of A/(B+C) and B/C of (70/30)-(99/1) and (10/90)-(90/10), respectively. The elastomer has such characteristics that the number of carbon atoms of the α-olefin unit is 4 or higher but not higher than 20; that the content of the α-olefin unit is higher than 65wt.% but not higher than 95wt.%; that no crystal melting peak is observed with a differential scanning calorimeter; and that the density at 23 deg.C is lower than 0.880g/cm<3> .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to flexibility, scratch resistance,
The present invention relates to a polypropylene resin composition for automobile interior materials having excellent whitening resistance.

[0002]

2. Description of the Related Art Polypropylene resins are widely used in automobile interior materials due to their excellent cost performance. However, they have problems such as poor touch feeling and poor impact resistance due to their high rigidity. As a means for reducing the impact resistance and rigidity of a polypropylene resin, there is known a method of blowing ethylene gas during propylene polymerization to form an ethylene / propylene random copolymer obtained by copolymerizing ethylene. However, even if this method is used, the rigidity is not sufficiently reduced, and the surface gloss is too large and the matting effect is inferior. Further, impact resistance and flexibility can be imparted by adding a rubber represented by an ethylene / propylene copolymer elastomer (EPR) to a polypropylene resin. However, even if this method is used, there is a limit in imparting flexibility, and it is not possible to avoid adverse effects such as the surface being easily damaged and being susceptible to whitening at the time of impact.

[0003] In recent years, a polyolefin-based thermoplastic elastomer, which is a composite material of a polypropylene-based resin and a crosslinked rubber, has been developed and is being used for automobile interior materials.

[0004]

However, even with the above-mentioned olefin-based thermoplastic elastomers, there are problems that the surface is easily damaged, oil contained in the material may bleed, and whitening is likely to occur upon impact. Has been pointed out, there is a major restriction on the use,
Although there is a strong need for polypropylene-based resins suitable for automotive interior materials, there have not been any materials that exhibit satisfactory properties.

Accordingly, an object of the present invention is to provide a polypropylene resin composition for an automobile interior material which is excellent in flexibility, scratch resistance and whitening resistance.

[0006]

Means for Solving the Problems The present inventors have made intensive studies to achieve the above object, and as a result, an ethylene / α-olefin copolymer elastomer having specific properties has been added to a polypropylene resin. The present inventors have found that a polypropylene-based resin composition containing a specific amount of talc has excellent properties as an automotive interior material, and have completed the present invention.

That is, the present invention relates to a weight ratio of a polypropylene resin (A), talc (B) and an ethylene / α-olefin copolymer elastomer (C) having the following characteristics (a) to (d). The ratio is (A) / ((B) +
(C)) = 70 / 30-99 / 1, (B) / (C) = 1
A polypropylene-based resin composition for an automobile interior material, comprising 0/90 to 90/10.

(A) carbon number of α-olefin: 4 or more, 2
0 or less (b) α-olefin content: greater than 65% by weight and 9
5% by weight or less (c) Crystal melting peak by differential scanning calorimeter: not observed (d) Density at 23 ° C of less than 0.880 g / cm ^{3 The} present invention will be described in detail below.

As the polypropylene resin (A) used in the present invention, a general crystalline polypropylene resin can be used. For example, a polypropylene homopolymer,
Propylene / ethylene random copolymer having an ethylene content of 0.5 to 12% by weight, an ethylene content of 0.5 to 12% by weight, and an α-olefin content such as 1-butene of 0.5
Propylene / ethylene / α-olefin terpolymer of about 20% by weight, impact polypropylene having an ethylene content of 1 to 60% by weight, crystalline polypropylene resin having a syndiotactic structure, and the like. One or more kinds are used.

[0010] The melt flow rate of the polypropylene resin (A) used in the present invention is not particularly limited, and is 0.01 to 1 at 230 ° C under a load of 2.16 kg.
A resin having a workability of 00 g / 10 minutes is preferably used because it becomes a polypropylene resin composition for automotive interior materials having excellent workability.

The talc (B) used in the present invention is not particularly limited, but those having an average particle size of 0.5 to 10 μm are preferably used. When the average particle size is less than 0.5 μm, uniform dispersion by kneading becomes extremely difficult,
If the ratio exceeds the above range, the impact strength and surface appearance of the obtained composition will be impaired, which is not preferred. Further, talc may be used without treatment or may be used, but for the purpose of improving dispersibility, various silane coupling agents, fatty acids, fatty acid esters, fatty acid salts, or surface-treated with a surfactant or the like. A thing may be used.

The ethylene / α- used in the present invention
The olefin copolymer elastomer is characterized in that it is compatible with the amorphous phase of polypropylene. In order to achieve good compatibility with the amorphous phase of polypropylene, it is necessary to use a copolymer as shown below.

The ethylene / α- used in the present invention
The α-olefin of the olefin copolymer elastomer (C) has 4 to 20 carbon atoms, and examples of such α-olefin include 1-butene, 1-pentene, 1-hexene, 4-hexene, Methyl-1-pentene, 1
-Heptene, 1-octene, 1-nonene, 1-decene,
1-undecene, 1-dodecene, 1-tridecene, 1-
Tetradecene, 1-pentadecene, 1-hexadecene,
1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, etc.
More than one species is used. Among them, 1-butene, 1-heptene, 1-hexene, 1-octene and the like are preferable from the viewpoint of availability. α-olefin having less than 4 or 20 carbon atoms
If it exceeds, the compatibility with the polypropylene resin is lowered, and the scratch resistance, flexibility and the like are impaired.

The ethylene / α- used in the present invention
The α-olefin content of the olefin copolymer elastomer (C) is greater than 65% by weight and 95% by weight or less, preferably 70% by weight or more and 95% by weight or less. When the α-olefin content is 65% by weight or less or greater than 95% by weight, the resulting polypropylene resin composition for an automotive interior material has poor scratch resistance and whitening resistance, which is not preferable.

The ethylene / α- used in the present invention
The olefin copolymer elastomer (C) has a density at 23 ° C. of less than 0.880 g / cm ³ .
In consideration of actual production, the density of the ethylene / α-olefin copolymer elastomer is 0.850 g / cm ^3.
It is preferably at least 0.880 g / cm ³ . Density is 0.
When an ethylene / α-olefin-based copolymer elastomer of 880 g / cm ³ or more is used, the resulting polypropylene-based resin composition for automotive interior materials has poor whitening resistance and scratch resistance, which is not preferable.

The ethylene / α- used in the present invention
The olefin copolymer elastomer (C) is characterized in that no crystal melting peak is observed by a differential scanning calorimeter (DSC). Ethylene showing crystal melting peak /
It is not preferable to use an α-olefin copolymer because the resulting resin composition suffers from poor whitening property and flexibility.

The ethylene / α- used in the present invention
The molecular weight of the olefin copolymer elastomer (C) is
There is no particular limitation. In order for the resulting polypropylene resin composition for automotive interior materials to have excellent workability and product appearance, the number average molecular weight measured by gel permeation chromatography (GPC) is 5,000 to 1,000,000 in terms of polyethylene. Preferably, it is 300 for good mechanical properties.
It is particularly preferable that it is 00 to 500,000.

The ethylene / α- used in the present invention
The molecular weight distribution (Mw / Mn) of the olefin-based copolymer elastomer (C) is not particularly limited, but is preferably 3 or less, and as an index of the composition distribution, a high molecular weight fraction of 10%
The ratio of the average α-olefin content (mol%) in the low-molecular-weight fraction 10% to the average α-olefin content (mol%) is preferably 1.2 or less, more preferably 1.15.
It is particularly preferred that:

The method for producing the above-mentioned ethylene / α-olefin copolymer is not particularly limited, and it can be produced using various catalysts such as a titanium-based catalyst, a vanadium-based catalyst, and a metallocene-based catalyst. Especially, it is preferable to manufacture using a metallocene catalyst excellent in copolymerizability. By this method, it is possible to obtain a copolymer having a high activity and a narrow molecular weight distribution and composition distribution.

As the metallocene catalyst, a combination of a metallocene compound and an aluminoxane compound (Japanese Patent Laid-Open No.
Nos. 8-19309, 60-35006, 61-130314, and JP-A-3-163088), or an ionized ionic compound which reacts with a metallocene compound to form a stable anion. (Japanese Unexamined Patent Publication No. 1-502023, International Publication WO91 / 14713, WO92 / 017)
No. 23, JP-A-5-310829). However, it is generally known that, in ethylene / α-olefin copolymerization, the molecular weight decreases as the content of α-olefin increases. Therefore, in order to efficiently produce the ethylene / α-olefin copolymer elastomer of the present invention, it is preferable to use a catalyst comprising the following compound.

A) a transition metal compound represented by the following general formula (1) b) a cationic transition compound represented by the following general formulas (2), (3), (4) and (5) Component which can be a metal compound c) Organoaluminum compound represented by the following general formula (6) a) Transition metal compound is represented by the following general formula (1)

[0022]

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[Cp ^{1 is a} cyclopentadienyl group, an indenyl group, a fluorenyl group or a substituted product thereof;
p ² is an unsubstituted or substituted group (—R, —BR ² , —SiR ³ ,
^{-NR 2, -PR 2, -OR,} -SR, -F, -Cl, -
Br, -I: wherein R is hydrogen or a hydrocarbon group having 1 to 20 carbon atoms),
R ¹ and R ² are each independently hydrogen, halogen or a group having 1 to 1 carbon atoms.
12 are a hydrocarbon group, an alkoxy group or an aryloxy group, at least one of which is an aryl group or a substituted aryl group, M is titanium, zirconium or hafnium, and R ³ and R ⁴ are each independently hydrogen, Halogen, a hydrocarbon group having 1 to 12 carbon atoms, an alkoxy group or an aryloxy group].

As a specific example of the general formula (1), diphenylmethylene (cyclopentadienyl) (fluorenyl)
Zirconium dichloride, methylphenylmethylene (cyclopentadienyl) (fluorenyl) zirconium dichloride, diphenylmethylene (cyclopentadienyl) (2,7-di-t-butylfluorenyl) zirconium dichloride, methylphenylmethylene (cyclopentadiene) Enyl) (2,7-di-t-butylfluorenyl) zirconium dichloride, diphenylmethylene (cyclopentadienyl) (2,7-dimethylfluorenyl) zirconium dichloride, methylphenylmethylene (cyclopentadienyl) ( 2,7-dimethylfluorenyl) zirconium dichloride, diphenylmethylene (cyclopentadienyl) (2,7-diphenylfluorenyl) zirconium dichloride, methylphenylmethylene (cyclo Ntajieniru) (2,7-diphenyl fluorenyl) zirconium dichloride, diphenylmethylene (cyclopentadienyl) (a, i-dibenzo fluorenyl) zirconium dichloride, methylphenylmethylene (cyclopentadienyl) (a, i-
Dibenzofluorenyl) zirconium dichloride, diphenylmethylene (cyclopentadienyl) (b, h-
Dibenzofluorenyl) zirconium dichloride, methylphenylmethylene (cyclopentadienyl) (b,
h-dibenzofluorenyl) zirconium dichloride, di (4-tolyl) methylene (cyclopentadienyl) (fluorenyl) zirconium dichloride, di (4-biphenyl) methylene (cyclopentadienyl)
(Fluorenyl) zirconium dichloride, diphenylmethylene (cyclopentadienyl) (2-dimethylaminofluorenyl) zirconium dichloride, methylphenylmethylene (cyclopentadienyl) (2-dimethylaminofluorenyl) zirconium dichloride, diphenylmethylene ( Cyclopentadienyl) (2
-Methoxyfluorenyl) zirconium dichloride,
Methylphenylmethylene (cyclopentadienyl) (2
-Methoxyfluorenyl) zirconium dichloride,
Diphenylmethylene (3-methylcyclopentadienyl) (fluorenyl) zirconium dichloride, methylphenylmethylene (3-methylcyclopentadienyl) (fluorenyl) zirconium dichloride, diphenylmethylene (3,4-dimethylcyclopentadienyl) (fluorenyl) ) Zirconium dichloride, methylphenylmethylene (3,4-dimethylcyclopentadienyl) (fluorenyl) zirconium dichloride, and compounds in which zirconium of the above compound is replaced with titanium or hafnium, but is not limited thereto. . Among them, compounds having a substituted fluorenyl group as a ligand and having zirconium or hafnium as a central metal are preferred because they have excellent copolymerizability and can be made higher in molecular weight.

B) Components which can make the above transition metal compound a cationic transition metal compound include protonic acid (2), Lewis acid (3), ionized ionic compound (4) and Lewis acidic compound (5).

The protonic acid is represented by the following general formula (2)

[0027]

Embedded image

Wherein H is a proton, L ¹ is each independently a Lewis base, 1 is 0 <l ≦ 2,
¹ is a boron atom, an aluminum atom or a gallium atom, and R ⁵ is each independently a halogen-substituted aryl group having 6 to 20 carbon atoms. ] It is a compound represented by these.

The Lewis acid has the following general formula (3)

[0030]

Embedded image

Wherein C is a carbonium cation or a tropinium cation, M ¹ is a boron atom, an aluminum atom or a gallium atom, and R ⁵ is each independently a halogen-substituted aryl group having 6 to 20 carbon atoms. Group. ] It is a compound represented by these.

The ionized ionic compound has the following general formula (4)

[0033]

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[Wherein, M ² represents Group 2, 8, 9 or 9 of the periodic table;
A cation of a metal selected from Group 10, Group 11 or Group 12, L ² is a Lewis base or a cyclopentadienyl group, m is 0 ≦ m ≦ 2, M ¹ is a boron atom, an aluminum atom Or a gallium atom, and R ⁵ is each independently a halogen-substituted aryl group having 6 to 20 carbon atoms. ] It is a compound represented by these.

The Lewis acidic compound is represented by the following general formula (5)

[0036]

Embedded image

[In the formula, M ¹ is a boron atom, an aluminum atom or a gallium atom, and R ⁵ is each independently a halogen-substituted aryl group having 6 to 20 carbon atoms. ] It is a compound represented by these.

The protonic acid (2), Lewis acid (3), ionized ionic compound (4), and Lewis acidic compound (5) used as components of the catalyst of the present invention react with the above-mentioned transition metal compound, It is a compound that can form a cationic transition metal compound and provides a counter anion to the formed cationic transition metal compound.

Specific examples of the protonic acid represented by the general formula (2) include diethyloxonium tetrakis (pentafluorophenyl) borate, dimethyloxonium tetrakis (pentafluorophenyl) borate, tetramethyleneoxonium tetrakis (pentafluorophenyl) ) Borate, N, N-dimethylanilinium tetrakis (pentafluorophenyl) borate, tri-n-butylammonium tetrakis (pentafluorophenyl) borate, diethyloxonium tetrakis (pentafluorophenyl) aluminate, dimethyloxonium tetrakis (pentane) Fluorophenyl) aluminate, tetramethyleneoxoniumtetrakis (pentafluorophenyl) aluminate, N, N-dimethylaniliniumtetrakis Pentafluorophenyl) aluminate, but it can be exemplified tri -n- butylammonium tetrakis (pentafluorophenyl) aluminate, but are not limited thereto.

The Lewis acid represented by the general formula (3) is specifically trityltetrakis (pentafluorophenyl)
Examples thereof include, but are not limited to, borate, trityltetrakis (pentafluorophenyl) aluminate, tropylium tetrakis (pentafluorophenyl) borate, and tropylium tetrakis (pentafluorophenyl) aluminate.

Specific examples of the ionized ionic compound represented by the general formula (4) include lithium salts such as lithium tetrakis (pentafluorophenyl) borate and lithium tetrakis (pentafluorophenyl) aluminate, and ether complexes thereof. , Ferrocenium salts such as ferrocenium tetrakis (pentafluorophenyl) borate and ferrocenium tetrakis (pentafluorophenyl) aluminate, and silver such as silver tetrakis (pentafluorophenyl) borate and silver tetrakis (pentafluorophenyl) aluminate Salts and the like can be mentioned, but are not limited thereto.

As specific examples of the Lewis acidic compound represented by the general formula (5), tris (pentafluorophenyl) borane, tris (2,3,5,6-tetrafluorophenyl) borane, tris (2, 3,4,5-tetraphenylphenyl) borane, tris (3,4,5-trifluorophenyl) borane, phenylbis (pentafluorophenyl) borane, tris (3,4,5-trifluorophenyl) aluminum, etc. But are not limited to these.

C) As the organometallic compound, Periodic Table 1
Organic metals containing Sn, Zn, and Group III, Group III, and Group III are specifically exemplified by the following general formula (6):

[0044]

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[Wherein, M ³ represents the periodic table 1, 2, 3 group, Sn
Or it is an element of Zn. R ⁶ is each independently a hydrogen atom, an alkyl group or an alkoxy group having 1 to 24 carbon atoms, or an aryl group, an aryloxy group, an arylalkyl group, an arylalkoxy group, an alkylaryl group, or an alkyl group having 6 to 24 carbon atoms. An aryloxy group, wherein at least one R ⁶ is a hydrogen atom and has 1 to 24 carbon atoms;
Or an aryl group having 6 to 24 carbon atoms, an arylalkyl group or an alkylaryl group. n is equal to the oxidation number of M ^3. ] Is an organometallic compound represented by the formula:

The compound represented by the general formula (6) includes, for example, trimethylaluminum, triethylaluminum, triisopropylaluminum, tri-n-
Propyl aluminum, triisobutyl aluminum,
Tri-n-butylaluminum, triamylaluminum, dimethylaluminum ethoxide, diethylaluminum ethoxide, diisopropylaluminum ethoxide, di-n-propylaluminum ethoxide, diisobutylaluminum ethoxide, di-n-
Butyl aluminum ethoxide, dimethyl aluminum hydride, diethyl aluminum hydride,
Examples thereof include diisopropylaluminum hydride, di-n-propylaluminum hydride, diisobutylaluminum hydride, and di-n-butylaluminum hydride, but are not limited thereto.

The polymerization can be carried out by any of a batch system, a semi-continuous system and a continuous system, and can be carried out in two or more stages by changing the polymerization conditions. The copolymer obtained after the completion of the polymerization is separated and recovered from the polymerization solution by a conventionally known method, and dried to obtain a solid copolymer.

The polypropylene resin composition for an automobile interior material of the present invention comprises a polypropylene resin (A), talc (B) and an ethylene / α-olefin copolymer elastomer (C), and the weight ratio of each of them. Is (A) / ((B) + (C)) = 70/30 to 99/1. If the proportion of the polypropylene resin (A) is more than 99% or less than 70%, the resulting polypropylene resin composition for an automobile interior material has an extremely high hardness and undesirably sticks to the surface. The weight ratio of talc (B) to ethylene / α-olefin copolymer elastomer (C) is (B) / (C) = 1.
0/90 to 90/10. If the proportion of talc (B) is less than 10%, the gloss of the resulting polypropylene resin composition for automotive interior materials is increased, and the texture is impaired. If it exceeds 90%, the scratch resistance is impaired, which is not preferable.

The polypropylene resin (A) and the ethylene / α-olefin copolymer elastomer (C) used in the present invention are characterized by having excellent compatibility. There are various indices of compatibility, which can be determined by examining the glass transition temperature and the like. For example, by measuring the temperature dependence of solid viscoelasticity, the maximum of the loss tangent (tan δ) occurring in the range of −80 ° C. to 40 ° C. reflects the glass transition temperature. Object t
The number of peaks of an δ becomes single, which indicates that the polypropylene resin (A) and the ethylene / α-olefin copolymer elastomer (C) are compatible in the amorphous region.
If not compatible, polypropylene resin (A)
In addition to the peak due to the glass transition of, a tan δ peak derived from the glass transition temperature of the ethylene / α-olefin-based copolymer elastomer (C) can be observed. Or, it has poor scratch resistance. When impact polypropylene is used as the polypropylene resin (A), there is also a tan δ peak based on the ethylene / propylene copolymer contained in the polypropylene resin (A), and tan δ
In some cases, two peaks are observed, but this case is also within the scope of the present invention. In this case, if the shift temperature of the peak of tan δ derived from the amorphous region of polypropylene is the same as when using a polypropylene homopolymer,
It can be said that the ethylene / α-olefin copolymer elastomer is compatible with the amorphous region of polypropylene.

A softening agent can be added to the polypropylene resin composition for an automobile interior material according to the present invention as long as the object of the present invention is not deviated. As the softener, for example, paraffin softener, naphthene softener,
An aroma-based softener, asphalt, vaseline, ozokerite, tall oil, a low-polymerization degree phenol formaldehyde resin and a low-melting-point styrene resin may be used, and one or more of these may be used in combination.

The polypropylene resin composition for automobile interior materials of the present invention may further contain carbon black, silica, clay, kaolin, magnesium carbonate, calcium carbonate, aluminum hydroxide, wollastonite, montmorillonite, attapulgite, if necessary. And inorganic or organic pigments. In addition, crystal nucleating agents, clarifying agents, anti-blocking agents, release agents, antistatic agents, slip agents, anti-fog agents, lubricants, heat stabilizers, ultraviolet stabilizers, light stabilizers, weather resistance stabilizers, foaming agents If necessary, a fungicide, a rust preventive, an ion trap, a flame retardant, a flame retardant auxiliary, etc. may be added.

Further, the polypropylene resin composition for an automobile interior material of the present invention may be blended with another resin or rubber to such an extent that its performance is not impaired. In this case, a compatibilizer may be added as a further component as needed. Such other resins include linear high density polyethylene, linear low density polyethylene, branched low density polyethylene, ethylene / vinyl acetate copolymer (EV
A), ethylene / ethyl acrylate copolymer, poly (1-butene), polyamide, polyester, poly (4
-Methyl-1-pentene), styrene-isoprene-styrene block copolymer, styrene-ethylenebutene-
Examples include a styrene block copolymer, a styrene-ethylene propylene-styrene block copolymer, a styrene-butadiene-styrene block copolymer, and a polyolefin-based thermoplastic elastomer. Examples of the rubber include natural rubber, acrylonitrile / butadiene rubber, butadiene rubber, isoprene rubber, styrene / butadiene rubber and hydrogenated products thereof, silicone rubber, polynorbornene rubber, polyhexene rubber, ethylene / propylene rubber, ethylene / propylene rubber. / Diene random copolymer rubber and chloroprene rubber. further,
As the compatibilizer, acid-modified polyolefin and saponified E
Adhesive polymers such as VA, and block and graft copolymers represented by polyolefin-polyamide grafts or block copolymers are exemplified.

The polypropylene resin composition for automotive interior materials of the present invention is obtained by mixing a polypropylene resin (A), talc (B) and an ethylene / α-olefin copolymer elastomer (C) by any method. However, in order to improve dispersibility, it is preferable to perform melt blending using a kneader, a roll, a Banbury mixer, a single screw or twin screw extruder, or the like.

The polypropylene resin composition for an automobile interior material of the present invention is molded by any method such as blow molding and injection molding, and is used for automobile interior panels such as an instrument panel for an automobile, a trim for an automobile interior, and a pillar for an automobile interior. Materials are provided.

[0055]

The present invention will now be described by way of examples, which are illustrative and not restrictive. Various measurements in the examples and synthesis of the ethylene / α-olefin copolymer elastomer were performed by the following methods.

~ Measurement of α-olefin copolymerization amount ~ Ethylene / α-olefin copolymer elastomer (C)
Is 100 MH in o-dichlorobenzene / benzene-d6 (75/25% by volume) as a solvent.
The z, ¹³ C-NMR spectrum (manufactured by JEOL Ltd., trade name: JNM GX400) was measured and calculated by the following literature.

Macromolecules, 15, 1150 (1982), Macro
molecules, 15, 353 (1982), Macromolecules, 15, 1402
(1984), Polymer, 25, 441 (1984)-Measurement of molecular weight and molecular weight distribution-Gel permeation chromatography at 140 ° C using o-dichlorobenzene as a solvent (150C type GPC manufactured by Millipore Co., Ltd.) And calculated in terms of polyethylene.

Density: The sample was immersed in hot water at 100 ° C. for 1 hour, and then allowed to cool to room temperature. The density was measured using a density gradient tube maintained at 23 ° C. in accordance with JIS K6760 (1981).

Melting Point A temperature range from −100 ° C. to 200 ° C. was measured at a rate of 10 ° C./min using a differential scanning calorimeter (DSC) (Perkin Elmer, trade name: DSC-7).

-Impact whitening test-The whitening area was evaluated by visually observing a test piece after dropping a hitting body having a load of 100 g and a hitting weight of 0.5π from a height of 80 cm on a flat plate. Cradle inner diameter 43m
A 2 mm flat plate was cut into 50 mm × 50 mm as m and used.

Gloss The surface gloss (gloss) was measured according to JIS K7105 (1981).

-Olzen Flexural Elasticity- Based on JIS K7106 (1982), a D-type test piece was used to conduct an Olsen bending rigidity test at a temperature of 23 ° C. at a distance between supports of 30 mm and a thickness of 2 mm.

-Pencil Hardness- An experiment was conducted at 23 ° C. in accordance with JIS K5400 (1979). Scratches were drawn in the direction perpendicular to the flowing direction using pencils of various hardnesses, and whether or not scratches were formed was visually checked to determine the pencil hardness.

Synthesis Example 1 (Synthesis of Ethylene / α-Olefin Copolymer Elastomer) In a 5 l autoclave, 2000 ml of hexane and 1
-500 ml of hexene was added and the temperature was raised to 80 ° C. Further, ethylene was introduced so that the total pressure became 4 kg / cm ² . Next, 10 ml of toluene, 1.5 mmol of triisobutylaluminum, 3 μmol of diphenylmethylene (cyclopentadienyl) (fluorenyl) hafnium dichloride, and 3.6 μm of dimethylaniliniumtetrakispentafluorophenylborate were placed in another reaction vessel.
μmol was added, and the mixed solution was stirred for 20 minutes.
It was introduced into an autoclave and polymerization was started. This polymerization was carried out at 80 ° C. for 10 minutes by continuously introducing ethylene so as to keep the total pressure at 4 kg / cm ² .

After completion of the polymerization, the polymer was washed with a large amount of ethanol and dried at 60 ° C. for 12 hours under reduced pressure. As a result, ethylene / 1-hexene containing 82% by weight of ethylene / 1
-Hexene copolymer elastomer (C1) 95g was obtained. In the same manner, various ethylene / α-olefin copolymer elastomers were obtained. Table 1 shows the characteristic values of the obtained copolymer elastomer. In addition, the above-mentioned polymer was repeatedly polymerized as necessary to obtain a large amount of samples.

[0066]

[Table 1]

Example 1 Propylene homopolymer (Tosoh Polypro J5100)
A, manufactured by Tosoh Corporation, MFR = 10 g / 10 min) 600
g, 120 g of the ethylene / 1-hexene copolymer elastomer (C1) obtained in Synthesis Example 1, 80 g of talc (LSM # 300, manufactured by Fuji Talc), and a hindered phenol-based stabilizer (Irganox 1010) as a heat stabilizer. Ciba Geigy), phosphorus stabilizer (Irgafos 168)
1000 ppm each of Ciba Geigy Co., Ltd.) and 5000 ppm of calcium stearate as a lubricant were kneaded at 200 rpm at 60 rpm for 10 minutes using a 1-liter twin-screw kneader (Tosoh Seimitsu), followed by strand cutting. Was performed to obtain a pellet. The obtained pellet was injection molded to obtain a 2 mm-thick plate-shaped test piece. Injection molding is performed using Toshiba IS-50A with a cylinder temperature of 230
° C and the mold temperature were set to 40 ° C.

Using this test piece, impact whitening test, gloss, Olsen flexural modulus, pencil hardness, etc. were measured and evaluated. The results are shown in Table 2.

[0069]

[Table 2]

Example 2 Instead of a propylene homopolymer, an impact polypropylene resin (TOSOH POLYPRO J7090B, MFR: 9
g / 10 minutes, 230 ° C., 2.16 kg load), and a test piece was obtained in the same manner as in Example 1.

Using this test piece, impact whitening test, gloss, Olsen flexural modulus, pencil hardness, etc. were measured and evaluated. The results are shown in Table 2.

Example 3 Ethylene / 1-hexene copolymer elastomer (C1)
Example 1 was repeated except that the ethylene / 1-butene copolymer elastomer (C2) obtained in Synthesis Example 2 was used instead of
A test piece was obtained in the same manner as described above.

Using this test piece, an impact whitening test, gloss, Olsen flexural modulus, pencil hardness and the like were measured and evaluated. The results are shown in Table 2.

Examples 4 to 7 The propylene homopolymer used in Example 1
A test piece was obtained in the same manner as in Example 1 according to the composition shown in Table 2 with 1-hexene copolymer elastomer (C1) and talc. Using this test piece, an impact whitening test, gloss, Olsen flexural modulus, pencil hardness and the like were measured and evaluated. The results are shown in Table 2.

Comparative Example 1 Ethylene / 1-hexene copolymer elastomer (C1)
A test piece was obtained in the same manner as in Example 1 except that the test piece was not used. Using this test piece, an impact whitening test, gloss, Olsen flexural modulus, pencil hardness and the like were measured and evaluated. Table 3 shows the results.

[0076]

[Table 3]

Comparative Example 2 A test piece was obtained in the same manner as in Example 1 except that talc was not used. Using this test piece, an impact whitening test, gloss, Olsen flexural modulus, pencil hardness and the like were measured and evaluated. Table 3 shows the results.

Comparative Example 3 Ethylene / 1-hexene copolymer elastomer (C1)
A test piece was obtained in the same manner as in Example 2 except that the test piece was not used. Using this test piece, an impact whitening test, gloss, Olsen flexural modulus, pencil hardness and the like were measured and evaluated. Table 3 shows the results.

Comparative Example 4 Ethylene / 1-hexene copolymer elastomer (C1)
Instead of the 1-hexene content of 56 obtained in Synthesis Example 1,
A test piece was obtained in the same manner as in Example 1 except that the ethylene / 1-hexene copolymer elastomer (E1) was used in an amount of 1% by weight.

Using this test piece, impact whitening test, gloss, Olsen flexural modulus, pencil hardness and the like were measured and evaluated. Table 3 shows the results.

Comparative Example 5 Ethylene / 1-hexene copolymer elastomer (C1)
Instead of 75% by weight of propylene obtained in Synthesis Example 1
Ethylene / propylene copolymer elastomer (E2)
A test piece was obtained in the same manner as in Example 1 except that was used.

Using this test piece, impact whitening test, gloss, Olsen bending elastic modulus, pencil hardness and the like were measured and evaluated. Table 3 shows the results.

Synthesis Example 2 (Synthesis of Ethylene / 1-butene Copolymer Elastomer) In a 5 l autoclave, 500 ml of toluene and 1-
1000 ml of butene was added and the temperature was raised to 40 ° C. Further, ethylene was introduced so that the total pressure became 4 kg / cm ² . Next, 10 ml of toluene, 3 mmol of methylaluminoxane, dimethylsilylbis (2-
Methylindenyl) zirconium dichloride 3μmo
After the mixture was stirred for 20 minutes, the mixture was introduced into an autoclave and polymerization was started. This polymerization was carried out at 40 ° C. for 30 minutes by continuously introducing ethylene so as to keep the total pressure at 4 kg / cm ² .

After completion of the polymerization, the polymer was washed with a large amount of ethanol, and dried at 60 ° C. for 12 hours under reduced pressure. As a result, ethylene / 1- having a 1-butene content of 96% by weight.
54 g of a butene copolymer elastomer (E3) was obtained. This operation was repeated several times to obtain a sample. The properties of this elastomer are shown in Table 1.

Comparative Example 6 Ethylene / 1-hexene copolymer elastomer (C1)
Example 1 was repeated except that the ethylene / 1-butene copolymer elastomer (E3) obtained in Synthesis Example 2 was used instead of
A test piece was obtained in the same manner as described above.

Using this test piece, impact whitening test, gloss, Olsen flexural modulus, pencil hardness and the like were measured and evaluated. Table 3 shows the results.

Comparative Examples 7 to 9 The propylene homopolymer used in Example 1
A 1-hexene copolymer elastomer (C1) and talc were obtained in the same manner as in Example 1 according to the composition shown in Table 3 to obtain a test piece. Using this test piece, an impact whitening test, gloss, Olsen flexural modulus, pencil hardness and the like were measured and evaluated. Table 3 shows the results.

[0088]

As described above, the polypropylene resin composition of the present invention has excellent flexibility, scratch resistance, whitening resistance, and matting properties, and is a material suitable for automotive interior materials.

Claims (1)

[Claims] 1. A polypropylene resin (A), a talc (B) and an ethylene / α-olefin copolymer elastomer (C) having the following characteristics (a) to (d):
Is (A) / ((B) + (C)) = 70
/ 30-99 / 1, (B) / (C) = 10 / 90-90
A polypropylene-based resin composition for automotive interior materials characterized by the following: (A) α-olefin carbon number: 4 or more and 20 or less (b) α-olefin content: greater than 65% by weight and 9
5% by weight or less (c) Crystal melting peak by differential scanning calorimeter: not observed (d) Density at 23 ° C. is less than 0.880 g / cm ³