JP2008179795A - Polypropylenic resin composition, and molded product from the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polypropylenic resin composition and a polypropylenic resin composition containing an inorganic filler which can provide a molded product with little silver streak; and a molded product from the same. <P>SOLUTION: The polypropylenic resin composition comprises a propylene copolymer, a propylene-ethylene-α-olefin copolymer (B) and an ethylene-α-olefin copolymer (C), and has a melt index of more than 40 g/10 min and 200 g/10 min or less at 230°C and under a load of 2.16 kg, wherein the propylene-ethylene-α-olefin copolymer (B) has an α-olefin carbon number of 4-20, a molecular weight distribution of 1-4, a limiting viscosity of 0.5-10 dl/g, a melting heat of 30 J/g or less, and an ethylene content of 60 mol% or less; and the ethylene-α-olefin copolymer (C) has an α-olefin carbon number of 4-20, and a density of 0.85-0.89 g/cm<SP>3</SP>. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a polypropylene resin composition, an inorganic filler-containing polypropylene resin composition, and a molded article comprising the same. More specifically, the present invention relates to a polypropylene resin composition, an inorganic filler-containing polypropylene resin composition, and a molded body comprising the same, which can obtain a molded product with less silver streak.

Conventionally, polypropylene resins have been used for automobile materials because of their high rigidity and excellent impact resistance.
For example, in JP-A-11-293058, as means for improving rigidity and impact resistance, polypropylene resin and two or more olefins selected from ethylene, propylene, and α-olefin, A thermoplastic resin composition comprising an olefin copolymer obtained by copolymerizing an olefin having a total carbon number of 6 or more and an inorganic filler is described.

  Japanese Patent Application Laid-Open No. 2001-192509 includes, as a means for improving flexibility and heat resistance, an amorphous olefin polymer having a strength at tensile cutting of less than 2 MPa, and a crystalline olefin resin. An olefin resin composition having a Shore A hardness of 85 or less is described.

Japanese Patent Laid-Open No. 11-293058 JP 2001-192509 A

However, also in the polypropylene resin composition described in the above-mentioned publications and the like, reduction of silver streaks generated when the resin composition is molded into a molded body has been demanded.
Under such circumstances, an object of the present invention is to provide a polypropylene-based resin composition, an inorganic filler-containing polypropylene-based resin composition, and a molded body comprising the same, from which a molded product with less silver streak can be obtained.

As a result of intensive studies, the present inventor has found that the present invention can solve the above problems, and has completed the present invention.
That is, one aspect of the present invention is
At least one propylene polymer (A) selected from the group consisting of a propylene homopolymer (A-1) and a propylene-ethylene copolymer (A-2);
5-20% by weight of the following propylene-α-olefin copolymer (B),
Containing 5 to 30% by weight of the following ethylene-α-olefin copolymer (C),
Polypropylene resin composition having a melt index of more than 40 g / 10 min and not more than 200 g / 10 min at 230 ° C. and a load of 2.16 kg (however, the total of (A), (B) and (C) is 100 wt. %).
In the propylene-α-olefin copolymer (B), the α-olefin has 4 to 20 carbon atoms, a molecular weight distribution of 1 to 4, an intrinsic viscosity of 0.5 to 10 dl / g, and a heat of fusion. Is a propylene-ethylene-α-olefin copolymer having an ethylene content of 60 mol% or less.
The ethylene-α-olefin copolymer (C) is an ethylene-α-olefin copolymer having an α-olefin having 4 to 20 carbon atoms and a density of 0.85 to 0.89 g / cm ³ .

Also, one aspect of the present invention is
At least one propylene polymer (A) selected from the group consisting of a propylene homopolymer (A-1) and a propylene-ethylene copolymer (A-2);
5-20% by weight of the following propylene-α-olefin copolymer (B),
A polypropylene resin composition containing 5 to 30% by weight of the following ethylene-α-olefin copolymer (C) (provided that the total of (A), (B) and (C) is 100% by weight) And an inorganic filler-containing polypropylene-based resin composition containing an inorganic filler (D),
The inorganic filler (D) is 0.1 to 40 parts by weight with respect to 100 parts by weight of the polypropylene resin composition,
This relates to an inorganic filler-containing polypropylene-based resin composition having a melt index at 230 ° C. and a load of 2.16 kg of more than 40 g / 10 minutes and 200 g / 10 minutes or less.
In the propylene-α-olefin copolymer (B), the α-olefin has 4 to 20 carbon atoms, a molecular weight distribution of 1 to 4, an intrinsic viscosity of 0.5 to 10 dl / g, and a heat of fusion. Is a propylene-ethylene-α-olefin copolymer having an ethylene content of 60 mol% or less.
The ethylene-α-olefin copolymer (C) is an ethylene-α-olefin copolymer having an α-olefin having 4 to 20 carbon atoms and a density of 0.85 to 0.89 g / cm ³ .

Moreover, one aspect of the present invention relates to an injection-molded article made of the above polypropylene resin composition or an inorganic filler-containing polypropylene resin composition.
Moreover, one aspect of the present invention relates to a foamed molded article made of the above polypropylene resin composition or the inorganic filler-containing polypropylene resin composition.

  According to the present invention, it is possible to obtain a polypropylene-based resin composition, an inorganic filler-containing polyolefin-based resin composition, and a molded body comprising the same, which can obtain a molded product with less silver streak.

[Propylene polymer (A)]
In the present invention, at least one propylene polymer (A) selected from the group consisting of a propylene homopolymer (A-1) and a propylene-ethylene copolymer (A-2) is used.
Examples of the propylene-ethylene copolymer (A-2) include a propylene-ethylene random copolymer (A-2-1) and a propylene-ethylene block copolymer (A-2-2). The propylene-ethylene block copolymer (A-2-2) is a copolymer composed of a propylene homopolymer component and a propylene-ethylene random copolymer component.

  The propylene polymer (A) is preferably a propylene homopolymer (A-1) or a propylene-ethylene block copolymer (A-2-2) from the viewpoint of increasing rigidity, heat resistance or hardness. .

The isotactic pentad fraction measured by ¹³ C-NMR of the propylene homopolymer (A-1) is preferably 0.95 or more, more preferably 0.98 or more.
The isotactic pentad fraction measured by ¹³ C-NMR of the propylene homopolymer component of the propylene-ethylene block copolymer (A-2-2) is preferably 0.95 or more, more preferably 0.8. 98 or more.

The isotactic pentad fraction is the fraction of the propylene monomer unit at the center of the isotactic chain in the pentad unit in the propylene polymer molecular chain. In other words, five propylene monomer units are consecutive. This is the fraction of propylene monomer units at the center of the meso-linked chain. The method for measuring the isotactic pentad fraction is as follows. Zambelli et al., Described in Macromolecules, 6, 925 (1973), that is, a method measured by ¹³ C-NMR. (However, the assignment of the NMR absorption peak is determined based on Macromolecules, 8, 687 (1975)).

Specifically, the ratio of the mmmm peak area to the absorption peak area of the methyl carbon region measured by ¹³ C-NMR spectrum is the isotactic pentad fraction. NPL reference material CRM No. of NATIONAL PHYSICAL LABORATORY measured by this method. The isotactic pentad fraction of M19-14 Polypropylene PP / MWD / 2 was 0.944.

Intrinsic viscosity ([η] _P ) measured in a tetralin solvent at 135 ° C. of the propylene homopolymer (A-1), 135 ° C. of the propylene homopolymer component of the block copolymer (A-2-2) Intrinsic viscosity ([η] _P ) measured in a tetralin solvent, and the intrinsic viscosity ([η]) measured in a 135 ° C. tetralin solvent of the random copolymer (A-2-1) is usually It is 0.7-5 dl / g, Preferably it is 0.8-4 dl / g.

  In addition, propylene homopolymer (A-1), propylene homopolymer component of block copolymer (A-2-2), and gel permeation chromatography of random copolymer (A-2-1) ( The molecular weight distribution (Q value, Mw / Mn) measured by GPC) is preferably 3 or more and 7 or less.

  The ethylene content contained in the propylene-ethylene random copolymer component of the block copolymer (A-2-2) is 20 to 65% by weight, preferably 25 to 50% by weight (provided that propylene-ethylene is used). The total amount of random copolymer components is 100% by weight).

The intrinsic viscosity ([η] _EP ) measured in a 135 ° C. tetralin solvent of the propylene-ethylene random copolymer component of the block copolymer (A-2-2) is usually 1.5 to 12 dl / g, preferably 2 to 8 dl / g.

  Content of the propylene-ethylene random copolymer component which comprises the said block copolymer (A-2-2) is 10 to 60 weight%, Preferably it is 10 to 40 weight%.

  The melt index (MI) of the propylene homopolymer (A-1) is usually 0.1 to 400 g / 10 minutes, preferably 1 to 300 g / 10 minutes. However, the measurement temperature is 230 ° C. and the load is 2.16 kg.

  The melt index (MI) of the propylene-ethylene copolymer (A-2) is usually 0.1 to 200 g / 10 minutes, preferably 5 to 150 g / 10 minutes. However, the measurement temperature is 230 ° C. and the load is 2.16 kg.

As a manufacturing method of the said propylene polymer (A), the method of manufacturing with a well-known polymerization method using a well-known polymerization catalyst is mentioned, for example.
Examples of the known polymerization catalyst used in the method for producing the propylene polymer (A) include (1) a solid catalyst component containing magnesium, titanium, halogen and an electron donor as essential components, and (2) organoaluminum. And a catalyst system comprising a compound and (3) an electron donor component. Examples of the method for producing this catalyst include the production methods described in JP-A-1-319508, JP-A-7-216017 and JP-A-10-212319.

  Examples of known polymerization methods used in the above production method include a bulk polymerization method, a solution polymerization method, a slurry polymerization method, and a gas phase polymerization method. These polymerization methods may be either batch type or continuous type, and these polymerization methods may be arbitrarily combined.

As a manufacturing method of said propylene-ethylene block copolymer (A-2-2), Preferably, it consists of said solid catalyst component (1), an organoaluminum compound (2), and an electron donor component (3). In the presence of a catalyst system, a polymerization tank comprising at least two tanks is arranged in series to produce a propylene homopolymer component of the propylene-ethylene block copolymer, and then the produced component is transferred to the next polymerization tank. In this polymerization tank, a propylene-ethylene random copolymer component is continuously produced to produce a propylene-ethylene block copolymer.
The amount of the solid catalyst component (1), the organoaluminum compound (2) and the electron donor component (3) used in the above production method and the method of supplying each catalyst component to the polymerization tank may be appropriately determined. .

  The polymerization temperature is usually −30 to 300 ° C., preferably 20 to 180 ° C. The polymerization pressure is usually normal pressure to 10 MPa, preferably 0.2 to 5 MPa. For example, hydrogen may be used as the molecular weight modifier.

  In the production of the propylene polymer (A), prepolymerization may be performed by a known method before carrying out the main polymerization. As a known prepolymerization method, for example, a method of supplying a small amount of propylene in the presence of the solid catalyst component (1) and the organoaluminum compound (2) and carrying out in a slurry state using a solvent can be mentioned.

[Propylene-α-olefin copolymer (B)]
The propylene-α-olefin copolymer (B) (hereinafter also referred to as copolymer (B)) used in the present invention refers to a propylene-ethylene-α-olefin copolymer or a mixture thereof. Examples of the α-olefin used in the propylene-ethylene-α-olefin copolymer include α-olefins having 4 to 20 carbon atoms.
Examples of the α-olefin having 4 to 20 carbon atoms include a linear α-olefin and a branched α-olefin, and examples of the linear α-olefin include 1-butene, 1-pentene, 1-hexene, 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-nanodecene, 1-eicosene and the like. Examples of the branched α-olefin include 3-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene, 2-ethyl-1-hexene and the like.

The propylene content contained in the copolymer (B) is 5 to 99 mol%, preferably 25 to 99 mol%, more preferably 35 to 99 mol%,
The ethylene content is 0 to 60 mol%, preferably 0 to 55 mol%,
The α-olefin content is 1 to 35 mol%, preferably 1 to 20 mol%, more preferably 1 to 10 mol%. (However, the total of the propylene content, ethylene content, and α-olefin content is 100 mol%.)

The copolymer (B) preferably satisfies the relationship of the following formula.
0.1 <[y / (x + y)] ≦ 1.0
More preferably, 0.5 <[y / (x + y)] ≦ 1.0, and still more preferably 0.8 <[y / (x + y)] ≦ 1.0.
In the above formula, x represents the molar content of ethylene in (B), and y represents the total molar content of α-olefins having 4 to 20 carbon atoms in (B).

Examples of the method for producing the copolymer (B) include a method in which a predetermined monomer is polymerized using a metallocene catalyst by a slurry polymerization method, a solution polymerization method, a bulk polymerization method, a gas phase polymerization method, or the like.
Examples of the metallocene catalyst include, for example, Japanese Patent Application Laid-Open Nos. 3-163088, 4-268307, 9-12790, 9-87313, 11-80233, and special tables. Examples thereof include metallocene catalysts described in JP-A-10-508055.
As a method for producing a copolymer (B) using a metallocene catalyst, a method described in EP-A-1211287 is preferably mentioned.

  The intrinsic viscosity [η] measured in a tetralin solvent at 135 ° C. of the copolymer (B) is 0.5 to 10 dl / g, more preferably 0.9 to 5 dl / g, and still more preferably. 1.2 to 3 dl / g.

  The molecular weight distribution of the copolymer (B) is 1 to 4. The molecular weight distribution is the ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn), and is measured by gel permeation chromatography (GPC) using standard polystyrene as the molecular weight standard substance. Is done.

  The heat of fusion of the copolymer (B) is 30 J / g or less, preferably 20 J / g or less, and more preferably 10 J / g or less. More preferably, it is 0 J / g.

[Ethylene-α-olefin copolymer (C)]
Examples of the ethylene-α-olefin copolymer (C) (hereinafter also referred to as copolymer (C)) used in the present invention include an ethylene-α-olefin random copolymer or a mixture thereof.

The density of the copolymer (C) is 0.85 to 0.89 g / cm ³ , preferably 0.85 to 0.88 g / cm ³ , more preferably 0.86 to 0.88 g / cm ³ . is there.

  The ethylene content contained in the copolymer (C) is 20 to 95% by weight, preferably 30 to 90% by weight, and the α-olefin content is 80 to 5% by weight, preferably 70%. -10% by weight.

  The MI of the copolymer (C) (measurement temperature is 190 ° C., load is 2.16 kg) is 0.5 to 100 g / 10 min, preferably 1 to 50 g / 10 min, more preferably 10 to 40 g / min. 10 minutes.

  Examples of the α-olefin used in the copolymer (C) include α-olefins having 4 to 20 carbon atoms, such as 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, Examples include 1-heptene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, and 1-eicocene. These α-olefins may be used alone or in combination of at least two kinds. The α-olefin is preferably an α-olefin having 4 to 12 carbon atoms such as 1-butene, 1-hexene and 1-octene.

  As a manufacturing method of a copolymer (C), the manufacturing method similar to the method used for manufacture of a copolymer (B) is mentioned. As a catalyst used for manufacture of a copolymer (C), the same metallocene catalyst as the catalyst used for manufacture of a copolymer (B) is mentioned.

[Inorganic filler (D)]
Moreover, the polypropylene resin composition according to the present invention may contain an inorganic filler (D). Examples of the inorganic filler (D) include glass fiber, carbon fiber, metal fiber, glass bead, mica, calcium carbonate, potassium titanate whisker, talc, bentonite, smectite, mica, sepiolite, wollastonite, allophane, imogolite. , Fibrous magnesium oxysulfate, barium sulfate, glass flakes and the like, and talc is preferable.

  As an average particle diameter of an inorganic filler (D), it is 0.01-50 micrometers normally, Preferably it is 0.1-30 micrometers, More preferably, it is 0.1-5 micrometers. Here, the average particle size of the inorganic filler (D) was determined from the integral distribution curve of the sieving method measured by suspending in a dispersion medium such as water or alcohol using a centrifugal sedimentation type particle size distribution measuring device. It means a 50% equivalent particle diameter D50.

  The inorganic filler (D) may be used without any treatment, to improve the interfacial adhesive strength with the polypropylene resin composition, or to improve the dispersibility of the inorganic filler in the polypropylene resin composition. To treat the surface of the inorganic filler with various known silane coupling agents, titanium coupling agents, higher fatty acids, higher fatty acid esters, higher fatty acid amides, higher fatty acid salts or other surfactants. Also good.

  The content of the propylene polymer (A) is 50 to 90% by weight, preferably 55 to 85% by weight, and more preferably 60 to 80% by weight. The content of the propylene-α-olefin copolymer (B) is 5 to 20% by weight, preferably 5 to 15% by weight, and more preferably 7 to 15% by weight. As content of ethylene-alpha-olefin random copolymerization (C), it is 5 to 30 weight%, Preferably, it is 10 to 30 weight%, More preferably, it is 13 to 25 weight%. However, the total amount of (A), (B) and (C) is 100% by weight.

  As content of an inorganic filler (D), it is 0.1-40 weight part with respect to 100 weight part of polypropylene resin compositions containing (A), (B), and (C), Preferably, From the viewpoint of improving rigidity, it is 1 to 30 parts by weight, more preferably 5 to 20 parts by weight.

  MI (measurement temperature is 230 ° C., load is 2.16 kg) of the polypropylene resin composition and the inorganic filler-containing polypropylene resin composition of the present invention is more than 40 g / 10 minutes and not more than 200 g / 10 minutes, It is preferably more than 40 g / 10 minutes and 150 g / 10 minutes or less, more preferably more than 40 g / 10 minutes and 120 g / 10 minutes or less.

  Examples of the method for producing the polypropylene resin composition and the inorganic filler-containing polypropylene resin composition of the present invention include a method of kneading each component, and the apparatus used for kneading includes a single screw extruder, a twin screw extruder, A Banbury mixer, a heat roll, etc. are mentioned. The kneading temperature is usually 170 to 250 ° C., and the time is usually 1 to 20 minutes. In addition, the kneading of each component may be performed at the same time or may be performed separately.

  The polypropylene resin composition of the present invention and the inorganic filler-containing polypropylene resin composition may contain additives as necessary, for example, neutralizers, antioxidants, light resistance agents, ultraviolet absorption Agents, copper damage inhibitors, lubricants, processing aids, plasticizers, dispersants, antiblocking agents, antistatic agents, nucleating agents, flame retardants, foaming agents, antifoaming agents, crosslinking agents, colorants, pigments, etc. Can be mentioned.

  The molded article of the present invention is a molded article comprising the polypropylene resin composition of the present invention or an inorganic filler-containing polypropylene resin composition, and the polypropylene resin composition of the present invention or an inorganic filler-containing polypropylene resin composition. Examples of the method for molding a product include an injection molding method, an extrusion molding method, a rotational molding method, a vacuum molding method, a foam molding method, and a blow molding method.

The foamed molded article of the present invention is obtained by adding a foaming agent to the polypropylene resin composition or the inorganic filler-containing polypropylene resin composition of the present invention and molding. As a foaming agent used by this invention, well-known foaming agents, such as a chemical foaming agent and a physical foaming agent, are mentioned.
The method for foam-molding the polypropylene-based resin composition or the inorganic filler-containing polypropylene-based resin composition of the present invention specifically includes an injection foam molding method, a press foam molding method, an extrusion foam molding method, a stampable foam molding method, and the like. There are known methods.

  The foamed molded product of the present invention can be made into a decorative foamed molded product by bonding a skin material by a method such as insert molding or adhesion.

A known skin material can be used as the skin material. Specific skin materials include woven fabrics, non-woven fabrics, knitted fabrics, films and sheets made of thermoplastic resins or thermoplastic elastomers. Further, a composite skin material in which sheets of polyurethane, rubber, thermoplastic elastomer or the like are laminated on these skin materials may be used.
A cushion layer can be further provided on the skin material. Examples of the material constituting the cushion layer include polyurethane foam, EVA foam, polypropylene foam, and polyethylene foam.

  Examples of the use of the molded article of the present invention include automobile interior parts or exterior parts, motorcycle parts, furniture and electrical product parts.

  Examples of automobile interior parts include instrument panels, trims, door panels, side protectors, console boxes, column covers, and the like. Examples of automobile exterior parts include bumpers, fenders, wheel covers, and the like. Examples of the parts include a cowling and a muffler cover.

Hereinafter, the present invention will be described with reference to examples and comparative examples.
In the examples or comparative examples, the following resins and additives were used.
(1) Propylene-ethylene block copolymer (A-1)
It was prepared by a solvent polymerization method using the solid catalyst component described in JP-A-7-216017.
MI (230 ° C., 2.16 kg load): 130 g / 10 minutes Intrinsic viscosity [η] T of the entire propylene-ethylene block copolymer: 1.4 dl / g
Intrinsic viscosity [η] P of propylene homopolymer component: 0.8 dl / g
Weight ratio of propylene-ethylene random copolymer component to the whole copolymer: 12% by weight
Intrinsic viscosity [η] EP of propylene-ethylene random copolymer component: 6.0 dl / g
Ethylene content of propylene-ethylene random copolymer component: 30% by weight

(2) Propylene homopolymer (A-2)
It was produced by a gas phase polymerization method using a solid catalyst component described in JP-A-7-216017.
MI (230 ° C., 2.16 kg load): 20 g / 10 minutes

(3) Propylene homopolymer (A-3)
Product name: U501E1 manufactured by Sumitomo Chemical Co., Ltd.
MI (230 ° C., 2.16 kg load): 120 g / 10 min

(4) Propylene homopolymer (A-4)
It was produced by a gas phase polymerization method using a solid catalyst component described in JP-A-7-216017.
MI (230 ° C., 2.16 kg load): 300 g / 10 min

(5) Propylene homopolymer (A-5)
Product name: FS2011DG3 manufactured by Sumitomo Chemical Co., Ltd.
MI (230 ° C., 2.16 kg load): 2.5 g / 10 min

(6) Propylene-ethylene block copolymer (A-6)
It was prepared by a solvent polymerization method using the solid catalyst component described in JP-A-7-216017.
MI (230 ° C., 2.16 kg load): 30 g / 10 minutes Intrinsic viscosity [η] T of the entire propylene-ethylene block copolymer: 1.5 dl / g
Intrinsic viscosity [η] P of propylene homopolymer component: 1.05 dl / g
Weight ratio of propylene-ethylene random copolymer component to the entire copolymer: 16% by weight
Intrinsic viscosity [η] EP of propylene-ethylene random copolymer component: 4.0 dl / g
Ethylene content of propylene-ethylene random copolymer component: 45% by weight

(7) Propylene-1-butene copolymer (B-1)
(7-1) Production of propylene-1-butene copolymer (B-1) From the lower part of a 100 L-SUS polymerizer equipped with a stirrer, to which a jacket for circulating cooling water was attached, was used as a polymerization solvent. In Example 25 of JP-A-9-87313, hexane was used as a polymerization catalyst component at a rate of 100 L / hour, propylene at a rate of 24.00 Kg / hour, and 1-butene at a rate of 1.81 Kg / hour. Dimethylsilyl (tetramethylcyclopentadienyl) (3-tert-butyl-5-methyl-2-phenoxy) titanium dichloride as described in Triphenylmethyltetrakis (pentafluorophenyl) borate at a rate of 0.005 g / hr The molecular weight at a rate of 0.298 g / hr and triisobutylaluminum at a rate of 2.315 g / hr. Hydrogen as an agent was continuously fed and copolymerized continuously at 45 ° C.

  After the polymerization reaction is stopped by adding a small amount of ethanol to the reaction mixture continuously withdrawn from the upper part of the polymerization vessel so that the reaction mixture in the polymerization vessel maintains an amount of 100 L, the demonomer and The solvent was washed with water, and then the solvent was removed with steam in a large amount of water to obtain a propylene-1-butene copolymer (B-1), which was dried under reduced pressure at 80 ° C. overnight. The production rate of the copolymer was 7.10 kg / hour. The structure of the obtained copolymer (B-1) is shown in Table 1.

(7-2) Propylene-butene copolymer masterbatch (B ′)
A propylene-1-butene copolymer masterbatch composed of 70% by weight of the propylene-1-butene copolymer (B-1) obtained above and 30% by weight of a propylene homopolymer (A-5). The MI (230 ° C., 2.16 kg load) was 2.6 g / 10 min.

(8) Ethylene-α-olefin copolymer (C)
(C-1) Ethylene-butene copolymer rubber Product name: CX5505 (manufactured by Sumitomo Chemical Co., Ltd.)
Density: 0.875 (g / cm ³ )
MI (190 ° C., 2.16 kg load): 14 (g / 10 min)
(C-2) Ethylene-butene copolymer rubber Product name: GA801 (manufactured by Sumitomo Chemical Co., Ltd.)
Density: 0.920 (g / cm ³ )
MI (190 ° C., 2.16 kg load): 20 (g / 10 min)
(C-3) Ethylene-butene copolymer rubber Product name: CX5501 (manufactured by Sumitomo Chemical Co., Ltd.)
Density: 0.880 (g / cm ³ )
MI (190 ° C., 2.16 kg load): 30 (g / 10 min)
(C-4) Ethylene-butene copolymer rubber Product name: A35050 (Mitsui Chemicals, Inc.)
Density: 0.863 (g / cm ³ )
MI (190 ° C., 2.16 kg load): 35 (g / 10 min)
(C-5) Ethylene-butene copolymer rubber Product name: A6050 (manufactured by Mitsui Chemicals, Inc.)
Density: 0.863 (g / cm ³ )
MI (190 ° C., 2.16 kg load): 6 (g / 10 min)
(C-6) Ethylene-octene copolymer rubber Product name: Engage 8407 (manufactured by Dow Chemical Company)
Density: 0.870 (g / cm ³ )
MI (190 ° C., 2.16 kg load): 34 (g / 10 min)

(9) Talc (D)
Product name: JR-46 (particle size = 2.7 μm) manufactured by Hayashi Kasei Co., Ltd.

(10) Talc master batch (D ')
Product name: MF110 (a talc masterbatch containing propylene-ethylene block copolymer (A-6) and talc (D) and having a talc content of 70% by weight) manufactured by Sumitomo Chemical Co., Ltd.

[Example 1, Comparative Examples 1-2]
The inorganic filler-containing polypropylene resin composition was produced according to the following method.

Each component was uniformly premixed with a tumbler in the weight ratio shown in Table 2, and then using a twin-screw kneading extruder (TEX44SS 30BW-2V type manufactured by Nippon Steel), the cylinder temperature was 200 ° C. and the extrusion amount was 30. The inorganic filler-containing polypropylene resin composition was manufactured by kneading and extruding under 50 kg / hr, screw rotation speed of 300 rpm, and vent suction.
Using this inorganic filler-containing polypropylene resin composition, injection foam molding was performed using an ES2550 / 400HL-MuCell (clamping force 400 tons) injection molding machine manufactured by Engel. As a foaming agent, carbon dioxide was injected into the cylinder part in a supercritical state and molded.
As the mold, a mold having a molded body schematic dimension that can obtain the box-shaped molded product shown in FIG. 1 was used. The molded product part dimensions were 290 mm × 370 mm, height 45 mm, basic cavity clearance (initial plate thickness) 1.5 mmt in a clamped state, and a die having a direct gate as the gate structure was used.

  The cylinder temperature was set to 250 ° C. and the mold temperature was set to 50 ° C. After the mold was clamped, injection of the composition containing a foaming agent was started. After the composition was completely injected and filled into the mold cavity, the cavity wall surface of the mold was retreated by 2.0 mm to increase the cavity to foam the composition. The foamed composition was further cooled and completely solidified to obtain a foamed molded article. The occurrence of silver streaks in the range of a circle with a diameter of 60 mm shown in FIG. 1 was examined centering on a portion 100 mm away from the gate portion of the foam molded article. The results are shown in Table 2.

The measuring method of the physical property of the resin component and composition used in the Example and the comparative example was shown below.
(1) Melt index (MI, unit: g / 10 minutes)
It measured according to the method prescribed | regulated to JIS-K-6758.

(2) Structural analysis of propylene-ethylene block copolymer (2-1) Intrinsic viscosity of propylene-ethylene block copolymer (2-1-a) Intrinsic viscosity of propylene homopolymer component: [η] P
The intrinsic viscosity of the propylene homopolymer component of the propylene-ethylene block copolymer: [η] P is the propylene homopolymer taken out from the polymerization tank after the polymerization of the propylene homopolymer at the time of production. The [η] P of the coalescence was determined by measurement.

(2-1-b) Intrinsic viscosity of propylene-ethylene random copolymer component: [η] EP
Intrinsic viscosity of propylene-ethylene random copolymer component of propylene-ethylene block copolymer: [η] EP is intrinsic viscosity of propylene homopolymer component: [η] P and inherent propylene-ethylene block copolymer Viscosity: [η] T was measured, and the weight ratio: X of the propylene-ethylene random copolymer component to the entire propylene-ethylene block copolymer was calculated from the following formula using the following formula.
[η] EP = [η] T / X− (1 / X−1) [η] P
[η] P: Intrinsic viscosity of propylene homopolymer component (dl / g)
[η] T: intrinsic viscosity of the entire propylene-ethylene block copolymer (dl / g)

(2-1-c) Proportion of propylene-ethylene random copolymer component to the entire propylene-ethylene block copolymer: X
Weight ratio of propylene-ethylene random copolymer component to the entire propylene-ethylene block copolymer: X measures the heat of crystal fusion of the propylene homopolymer component and the entire propylene-ethylene block copolymer, and uses the following formula: Was calculated. The amount of crystal melting heat was measured by suggestive scanning thermal analysis (DSC).
X = 1− (ΔHf) T / (ΔHf) P
(ΔHf) T: calorific value of heat of the entire block copolymer (cal / g)
(ΔHf) P: heat of fusion of propylene homopolymer component (cal / g)

(3) Ethylene content of propylene-ethylene random copolymer component in propylene-ethylene block copolymer: (C2 ′) EP
Ethylene content of propylene-ethylene random copolymer component of propylene-ethylene block copolymer: (C2 ') EP is a measure of ethylene content (C2') T of the entire propylene-ethylene block copolymer by infrared absorption spectroscopy. And obtained by calculation using the following equation.
(C2 ') EP = (C2') T / X
(C2 ′) T: ethylene content of propylene-ethylene block copolymer as a whole (% by weight) (C2 ′) EP: ethylene content of propylene-ethylene random copolymer component (% by weight) X: propylene-ethylene random copolymer Weight ratio of the combined component to the entire propylene-ethylene block copolymer

(4) Heat of fusion of copolymer (B) Measurement was performed under the following conditions using a differential scanning calorimeter (DSC RDC220 manufactured by Seiko Denshi Kogyo Co., Ltd.).
(I) About 5 mg of the sample was heated from room temperature to 200 ° C. at a rate of temperature increase of 30 ° C./min, and held for 5 minutes after completion of the temperature increase.
(Ii) Next, the temperature was decreased from 200 ° C. to −100 ° C. at a temperature decreasing rate of 10 ° C./min.
(Iii) After completion of the temperature decrease, the temperature was maintained for 5 minutes, and then the temperature was increased from −100 ° C. to 200 ° C. at a rate of 10 ° C./min.
The peak observed in (iv) is the melting peak, and the heat of fusion was calculated from the peak area.

(5) Molecular weight distribution of copolymer (B) Using a gel permeation chromatograph (GPC) method, measurement was performed under the following conditions. From the obtained results, a weight average molecular weight (Mw) and a number average molecular weight (Mn) were calculated, and a molecular weight distribution (Mw / Mn) was calculated.
Equipment: 150C ALC / GPC manufactured by Waters
Column: Showa Denko Corporation Shodex Packed Column A-80M 2 temperature: 140 ° C
Solvent: o-dichlorobenzene Elution solvent flow rate: 1.0 ml / min
Sample concentration: 1 mg / ml
Measurement injection volume: 400 μl
Molecular weight reference material: Standard polystyrene Detector: Differential refraction

(6) Appearance evaluation of foam (silver streak)
The range of a circle with a diameter of 60 mm shown in FIG. 1 at a site 100 mm away from the gate part of the foamed molded product of the polypropylene resin composition obtained by foam molding was visually evaluated and judged as shown below. .
○: Silver streaks on the surface of the foamed molded product cannot be confirmed visually. Δ: Silver streaks are slightly noticeable. X: Silver streaks are conspicuous.

表中、Ｄ’成分５．０％は、ポリプロピレン１．５％と、タルク３．５％で構成されている。
Ａ、Ｂ’、Ｃ成分および、Ｄ’成分中のポリプロピレンの合計が１００重量％である。

In the table, 5.0% D 'component is composed of 1.5% polypropylene and 3.5% talc.
The total of polypropylene in the A, B ′, C component and D ′ component is 100% by weight.

The perspective view of the foaming molding of the polypropylene resin composition produced in Example 1. FIG.

Explanation of symbols

1: Gate contact portion 2: Site where silver streak was evaluated

Claims (4)

At least one propylene polymer (A) selected from the group consisting of a propylene homopolymer (A-1) and a propylene-ethylene copolymer (A-2);
5-20% by weight of the following propylene-α-olefin copolymer (B),
Containing 5 to 30% by weight of the following ethylene-α-olefin copolymer (C),
Polypropylene resin composition having a melt index of more than 40 g / 10 min and not more than 200 g / 10 min at 230 ° C. and a load of 2.16 kg (however, the total of (A), (B) and (C) is 100 wt. %).
In the propylene-α-olefin copolymer (B), the α-olefin has 4 to 20 carbon atoms, a molecular weight distribution of 1 to 4, an intrinsic viscosity of 0.5 to 10 dl / g, and a heat of fusion. Is a propylene-ethylene-α-olefin copolymer having an ethylene content of 60 mol% or less.
The ethylene-α-olefin copolymer (C) is an ethylene-α-olefin copolymer having an α-olefin having 4 to 20 carbon atoms and a density of 0.85 to 0.89 g / cm ³ . At least one propylene polymer (A) selected from the group consisting of a propylene homopolymer (A-1) and a propylene-ethylene copolymer (A-2);
5-20% by weight of the following propylene-α-olefin copolymer (B),
A polypropylene resin composition containing 5 to 30% by weight of the following ethylene-α-olefin copolymer (C) (provided that the total of (A), (B) and (C) is 100% by weight) And an inorganic filler-containing polypropylene-based resin composition containing an inorganic filler (D),
The inorganic filler (D) is 0.1 to 40 parts by weight with respect to 100 parts by weight of the polypropylene resin composition,
An inorganic filler-containing polypropylene-based resin composition having a melt index at 230 ° C. and a load of 2.16 kg of more than 40 g / 10 minutes and 200 g / 10 minutes or less.
In the propylene-α-olefin copolymer (B), the α-olefin has 4 to 20 carbon atoms, a molecular weight distribution of 1 to 4, an intrinsic viscosity of 0.5 to 10 dl / g, and a heat of fusion. Is a propylene-ethylene-α-olefin copolymer having an ethylene content of 60 mol% or less.
The ethylene-α-olefin copolymer (C) is an ethylene-α-olefin copolymer having an α-olefin having 4 to 20 carbon atoms and a density of 0.85 to 0.89 g / cm ³ .   An injection-molded article comprising the polypropylene resin composition according to claim 1 or the inorganic filler-containing polypropylene resin composition according to claim 2.   A foam molded article comprising the polypropylene resin composition according to claim 1 or the inorganic filler-containing polypropylene resin composition according to claim 2.

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