JP2006225418A - Polypropylene resin composition and molded item composed of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polypropylene resin composition that is excellent in rigidity, impact strength and fluidity and gives a molded item having no color unevenness and good external appearances, and an injection-molded item composed of the same. <P>SOLUTION: The polypropylene resin composition comprises 61-97 pts.wt. of a polypropylene resin (A), 1-9 pts.wt. of an elastomer (B) and 2-30 pts.wt. of an inorganic filler (C) (provided that the total of each weight of (A), (B) and (C) is 100 pts.wt. ), and further comprises 0.0001-1 pt.wt. of carbon black (D) having a pH of 3 or lower and 0.2-1 pt.wt. of zinc stearate (E), each based on 100 pts.wt. of the total of (A), (B) and (C). The injection-molded item composed of the same is also provided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polypropylene resin composition and a molded body comprising the same. More specifically, the present invention relates to a polypropylene resin composition excellent in rigidity, impact strength, fluidity, and having a molded product that has no color unevenness when molded, and an injection molded product comprising the same. is there.

  Polypropylene resins are used in products such as home appliance parts and automobile parts because of their excellent rigidity and impact strength. Many of these products are colored in order to satisfy demands such as luxury and high design.

  For example, in JP-A-2-43249, a propylene / α-olefin block copolymer resin has an acid group in the molecular structure for the purpose of preventing the formation of streaky color unevenness during injection molding. A polyolefin composition for injection molding containing a modified polyolefin is described.

  JP-A-5-39380 discloses a crystalline propylene polymer, specific talc, (RCOO) nM (here, for the purpose of improving the balance between rigidity and impact resistance and suppressing mold contamination. Wherein R is a monovalent hydrocarbon group which may contain a hydroxy group having a molecular weight of 250 to 500, n is a valence of metal M, M is lithium, calcium, strontium or barium). A propylene polymer composition is described.

  JP-A-10-60182 discloses a composition containing polyolefin, filler, pigment, and olefin polymer wax for the purpose of obtaining a good molded product with no color separation and uniform appearance. A polyolefin composition in which the olefin polymer wax is an olefin polymer wax having an acid value of 10 to 60 and / or an olefin polymer wax having a hydroxyl value of 10 to 60 is described.

JP-A-2-43249 JP-A-5-39380 Japanese Patent Laid-Open No. 10-60182

  However, even in the polyolefin composition described in the above publications, in addition to rigidity, impact strength, and fluidity, the appearance of the molded body may require further improvement. In addition to the properties, there has been a demand for improving the appearance of the molded body by suppressing the occurrence of uneven color of the molded body.

  Under such circumstances, an object of the present invention is a polypropylene resin composition excellent in rigidity, impact strength, and fluidity, and having a molded body that has no color unevenness and a good appearance when formed into a molded body, and An object of the present invention is to provide an injection molded body.

As a result of intensive studies in view of the actual situation, the present inventors have found that the present invention can solve the above problems, and have completed the present invention.
That is, the present invention
61-97 parts by weight of a polypropylene resin (A),
1 to 9 parts by weight of elastomer (B),
Containing 2 to 30 parts by weight of inorganic filler (C) (provided that the total weight of (A), (B) and (C) is 100 parts by weight),
For a total of 100 weights of (A), (B) and (C),
0.0001 to 1 part by weight of carbon black (D) having a pH of 3 or less,
The present invention relates to a polypropylene-based resin composition containing 0.2 to 1 part by weight of zinc stearate (E) and an injection-molded body comprising the same.

  According to the present invention, a polypropylene resin composition excellent in rigidity, impact strength, and fluidity, and having a molded article having no color unevenness when formed into a molded article, and an injection molded article comprising the same. Obtainable.

  The polypropylene resin (A) used in the present invention is usually a polypropylene resin having crystallinity. For example, a crystalline propylene homopolymer, a crystalline ethylene-propylene copolymer, a crystalline propylene-α- Examples thereof include olefin copolymers, and these may be used alone or in combination of at least two kinds.

  The α-olefin used in the crystalline propylene-α-olefin copolymer is an α-olefin having 4 or more carbon atoms, preferably an α-olefin having 4 to 20 carbon atoms, more preferably carbon. It is an α-olefin having a number of 4 to 12. For example, butene-1, pentene-1, hexene-1, heptene-1, octene-1, decene-1, etc. are mentioned. Examples of the crystalline propylene-α-olefin copolymer include a crystalline propylene-butene-1 copolymer and a crystalline propylene-hexene-1 copolymer.

  From the viewpoint of mechanical properties such as rigidity and impact resistance, the polypropylene resin having crystallinity is preferably a crystalline propylene homopolymer, a crystalline ethylene-propylene block copolymer, or a mixture thereof, and more Preferably, it is a crystalline ethylene-propylene block copolymer or a mixture of a crystalline ethylene-propylene block copolymer and a crystalline propylene homopolymer.

  The crystalline ethylene-propylene block copolymer used as the polypropylene resin (A) is a propylene homopolymer portion (referred to as a first segment) and an ethylene-propylene random copolymer portion (referred to as a second segment). A crystalline ethylene-propylene block copolymer.

  As the Q value (Mw / Mn) which is the ratio of the weight average molecular weight (Mw) and the number average molecular weight (Mn) measured by the gel permeation chromatography (GPC) method of the propylene homopolymer portion which is the first segment From the viewpoint of mechanical properties such as rigidity and impact resistance and moldability, it is preferably 3 to 5, and more preferably 3.5 to 4.5.

Further, the isotactic pentad fraction measured using ¹³ C-NMR of the first segment is preferably 0.98 or more, more preferably 0.99 or more, from the viewpoint of rigidity.

And as intrinsic viscosity ([(eta)] _P ) of the 135 degreeC tetralin solution of a 1st segment, from a viewpoint of a moldability, Preferably it is 0.7-1.2 dl / g, More preferably, it is 0.8-1. .1 dl / g.

The intrinsic viscosity ([η] _EP ) of the 135 ° C. tetralin solution of the ethylene-propylene random copolymer portion as the second segment is preferably 1 or more and less than 8 dl / g from the viewpoint of moldability and appearance. Preferably it is 1.5-7.5 dl / g.

The ethylene content [(C2 ′) _EP ] of the second segment is preferably 25 to 55% by weight and more preferably 35 to 45% by weight from the viewpoint of mechanical properties such as impact resistance ( However, the total weight of the second segment is 100% by weight).

  In addition, the ratio of the weight of the ethylene-propylene random copolymer portion (second segment) to the weight of the propylene homopolymer portion (first segment) (second segment / first segment) is from the viewpoint of moldability. Therefore, it is preferably 8/92 to 35/65.

  The crystalline propylene homopolymer used in the mixture of the crystalline ethylene-propylene block copolymer and the crystalline propylene homopolymer is propylene homopolymer which is the first segment of the crystalline ethylene-propylene block copolymer. Q value (Mw) which has the same physical properties as the polymer part and is the ratio of the weight average molecular weight (Mw) and the number average molecular weight (Mn) measured by the gel permeation chromatography (GPC) method / Mn) is preferably 3 to 5 and more preferably 3.5 to 4.5 from the viewpoint of mechanical properties such as rigidity and impact resistance and moldability.

Further, the isotactic pentad fraction measured by ¹³ C-NMR of the crystalline propylene homopolymer used in the above mixture is preferably 0.98 or more, more preferably from the viewpoint of rigidity. It is 0.99 or more.

The intrinsic viscosity ([η] _P ) of the 135 ° C. tetralin solution of the crystalline propylene homopolymer used in the above mixture is preferably 0.7 to 1.2 dl / g from the viewpoint of moldability. More preferably, it is 0.8-1.1 dl / g.

  As a manufacturing method of polypropylene resin (A) used by this invention, the method of manufacturing with a well-known polymerization method using a well-known stereoregular olefin polymerization catalyst is mentioned. Known catalysts include, for example, Ziegler-Natta catalyst systems, metallocene catalyst systems, catalyst systems combining them, etc., and known polymerization methods include, for example, bulk polymerization methods, solution polymerization methods, slurry polymerization methods , Gas phase polymerization methods, polymerization methods in which these polymerization methods are arbitrarily combined, and the like, and continuous gas phase polymerization methods are preferable.

  In particular, as a method for producing a crystalline ethylene-propylene block copolymer, preferably, propylene is homopolymerized in the presence of a stereoregular olefin polymerization catalyst to obtain a crystalline propylene homopolymer portion as a first segment. This is a production method comprising a first step and then a second step in which ethylene and propylene are copolymerized to obtain an ethylene-propylene random copolymer portion as a second segment.

  The content of the polypropylene resin (A) used in the present invention is 61 to 97 parts by weight, preferably 65 to 85 parts by weight, and more preferably 65 to 75 parts by weight (provided that the polypropylene resin is used). The total weight of the resin (A), the elastomer (B), and the inorganic filler (C) is 100 parts by weight).

  When the content of the polypropylene resin (A) used in the present invention is less than 61 parts by weight, the rigidity may be reduced, and when it exceeds 97 parts by weight, the impact strength may be reduced.

  Furthermore, as a polypropylene-based resin composition (A) used in the present invention, from the viewpoint of improving the appearance of the flow mark and improving the mechanical properties and fluidity without causing bumps in the molded product, Preferably, the polypropylene resin (A) is a resin containing the following polypropylene resin (A-1) and the following polypropylene resin (A-2).

  The polypropylene resin (A-1) is a resin excluding the polypropylene resin (A-2), the polypropylene resin (A-2) is a propylene homopolymer or an ethylene-propylene random copolymer, and 135 The first segment 60-80 wt% whose intrinsic viscosity of the tetralin solution at 5 ° C is 5 dl / g or more, a propylene homopolymer or an ethylene-propylene random copolymer, and the intrinsic viscosity of the 135 ° C tetralin solution is 0.8- It is a resin containing 20 to 40% by weight of the second segment of 1.2 dl / g (provided that the total amount of (A-2) is 100% by weight).

When the polypropylene resin (A) is a resin containing the polypropylene resin (A-1) and the polypropylene resin (A-2), each of the resin (A-1) and the resin (A-2) The content is preferably from 56 to 96.9 parts by weight of the resin (A-1) from the viewpoint of improving the flow mark appearance and fluidity of the molded body, and the resin (A-2). Is 0.1 to 5 parts by weight. More preferably, the content of the resin (A-2) is 0.5 to 4.5 parts by weight, and still more preferably the content of the resin (A-2) is 1.0 to 4.5 parts by weight. . (However, the total amount of the polypropylene resin (A) containing the resin (A-1) and the resin (A-2) is 61 to 97 parts by weight.)
As a manufacturing method of the 1st segment and 2nd segment of a polypropylene resin (A-2), the method of manufacturing with a well-known polymerization method using a well-known stereoregular olefin polymerization catalyst system is mentioned. Known catalysts include, for example, Ziegler-Natta catalyst systems, metallocene catalyst systems, or catalyst systems combining these catalyst systems. Known polymerization methods include, for example, a bulk polymerization method, a solution polymerization method, a slurry polymerization method or a gas phase polymerization method, or a polymerization method in which these polymerization methods are arbitrarily combined. It is a phase polymerization method.

And as a manufacturing method of polypropylene resin (A-2), for example,
(1) Propylene is polymerized or propylene and ethylene are polymerized to individually produce the first segment and the second segment, and then the first segment and the second segment are mixed or melt-kneaded. A method for producing the resin (A-2),
(2) polymerizing propylene or polymerizing propylene and ethylene to produce a first segment; polymerizing propylene; or polymerizing propylene and ethylene; Examples include a method of producing the resin (A-2) by continuously carrying out the production steps in an arbitrary order.

  Preferably, the step of producing the first segment by polymerizing propylene of the above (2) or polymerizing propylene and ethylene, polymerizing propylene, or polymerizing propylene and ethylene And the step of producing the second segment are continuously carried out in an arbitrary order to produce the resin (A-2).

  The elastomer (B) used in the present invention is an elastomer containing a rubber component. For example, an elastomer containing a vinyl aromatic compound-containing rubber, an elastomer containing an ethylene-α-olefin random copolymer rubber, and an elastomer containing a mixture of these rubber components may be used.

  When the elastomer (B) is an elastomer containing a vinyl aromatic compound-containing rubber, examples of the vinyl aromatic compound-containing rubber include a block copolymer comprising a vinyl aromatic compound polymer block and a conjugated diene polymer block. And a block copolymer in which a conjugated diene moiety contained in the block copolymer is hydrogenated.

  The proportion of hydrogenated double bonds contained in the block copolymer in which the conjugated diene moiety is hydrogenated is preferably 80% by weight or more, more preferably 85% by weight from the viewpoint of weather resistance. % (Provided that the total weight of double bonds in the conjugated diene moiety is 100% by weight).

  The molecular weight distribution (Q value) measured by a GPC (gel permeation chromatography) method of the vinyl aromatic compound-containing rubber is preferably 2.5 or less, more preferably from the viewpoint of mechanical properties. 2.3 or less.

  The average content of the vinyl aromatic compound contained in the vinyl aromatic compound-containing rubber is preferably 10 to 20% by weight, more preferably 12 from the viewpoint of mechanical properties such as rigidity and impact resistance. -19% by weight (provided that the total weight of the vinyl aromatic compound-containing rubber is 100% by weight).

  Further, the melt flow rate (MFR, JIS-K-6758, 230 ° C.) of the vinyl aromatic compound-containing rubber is preferably 1 to 15 g / 10 minutes, more preferably 2 to 13 g from the viewpoint of moldability. / 10 minutes.

  Examples of the vinyl aromatic compound-containing rubber include styrene-ethylene-butene-styrene rubber (SEBS), styrene-ethylene-propylene-styrene rubber (SEPS), styrene-butadiene rubber (SBR), and styrene- Examples thereof include block copolymers such as butadiene-styrene rubber (SBS) and styrene-isoprene-styrene rubber (SIS), and block copolymers obtained by hydrogenating these rubber components.

  A rubber obtained by reacting an olefin copolymer rubber such as ethylene-propylene-nonconjugated diene rubber (EPDM) with a vinyl aromatic compound such as styrene can also be suitably used. Further, at least two types of vinyl aromatic compound-containing rubbers may be used in combination.

  Examples of the method for producing a vinyl aromatic compound-containing rubber include a production method in which a vinyl aromatic compound is bonded to an olefin copolymer rubber or a conjugated diene rubber by polymerization or reaction.

  When the elastomer (B) is an elastomer containing an ethylene-α-olefin random copolymer rubber, the ethylene-α-olefin random copolymer rubber is a random copolymer rubber composed of ethylene and an α-olefin. . The α-olefin is an α-olefin having 3 or more carbon atoms, and examples thereof include propylene, butene-1, pentene-1, hexene-1, heptene-1, octene-1, decene, etc., preferably propylene , Butene-1, hexene-1 and octene-1. The α-olefin may be used alone or in combination of at least two.

  Examples of the ethylene-α-olefin random copolymer rubber include ethylene-propylene random copolymer rubber, ethylene-butene-1 random copolymer rubber, ethylene-hexene-1 random copolymer rubber, and ethylene-octene- 1 random copolymer rubber and the like, and ethylene-octene-1 random copolymer rubber, ethylene-butene-1 random copolymer rubber, and ethylene-propylene random copolymer rubber are preferable. Moreover, you may use together at least 2 sorts of ethylene-alpha-olefin random copolymer rubber.

  The molecular weight distribution (Q value) measured by the GPC method of the ethylene-octene-1 random copolymer rubber is preferably 2.5 or less, more preferably 2.3 or less, from the viewpoint of mechanical properties. .

  Further, the content of octene-1 contained in the ethylene-octene-1 random copolymer rubber is preferably 15 to 45% by weight, more preferably 18 to 42% by weight from the viewpoint of impact resistance. (However, the total weight of the ethylene-octene-1 random copolymer rubber is 100% by weight).

  The melt flow rate (MFR, JIS-K-6758, 190 ° C.) of the ethylene-octene-1 random copolymer rubber is preferably 0.5 to 15 g / 10 from the viewpoint of moldability and impact resistance. Minute, more preferably 1 to 13 g / 10 minutes.

  The molecular weight distribution (Q value) measured by the GPC method of the ethylene-butene-1 random copolymer rubber is preferably 2.7 or less, more preferably 2.5 or less from the viewpoint of mechanical properties. .

  The content of butene-1 contained in the ethylene-butene-1 random copolymer rubber is preferably 15 to 35% by weight, more preferably 17 to 33% by weight from the viewpoint of impact resistance. (However, the total weight of the ethylene-butene-1 random copolymer rubber is 100% by weight).

  The melt flow rate (MFR, JIS-K-6758, 190 ° C.) of the ethylene-butene-1 random copolymer rubber is preferably 0.5 to 15 g / 10 from the viewpoint of impact resistance and moldability. Minute, more preferably 1 to 13 g / 10 minutes.

  The molecular weight distribution (Q value) measured by the GPC method of the ethylene-propylene random copolymer rubber is preferably 2.7 or less, more preferably 2.5 or less from the viewpoint of mechanical properties.

  Further, the content of propylene contained in the ethylene-propylene random copolymer rubber is preferably 20 to 30% by weight, more preferably 22 to 28% by weight from the viewpoint of impact resistance (provided that The total weight of the ethylene-propylene random copolymer rubber is 100% by weight).

  The melt flow rate (MFR, JIS-K-6758, 190 ° C.) of the ethylene-propylene random copolymer rubber is preferably 0.1 to 15 g / 10 minutes from the viewpoint of impact resistance and moldability. Yes, more preferably 1 to 13 g / 10 min.

  And as a manufacturing method of ethylene-alpha-olefin random copolymer rubber, the method of copolymerizing ethylene and at least 1 sort (s) of alpha-olefin by a well-known polymerization method using a well-known catalyst is mentioned. Known catalysts include, for example, a catalyst system comprising a vanadium compound and an organoaluminum compound, a Ziegler-Natta catalyst system, a metallocene catalyst system, etc., and known polymerization methods include solution polymerization, slurry polymerization, high pressure ion Examples thereof include a polymerization method and a gas phase polymerization method.

  The content of the elastomer (B) used in the present invention is 1 to 9 parts by weight, and preferably 3 to 8 parts by weight from the viewpoint of a balance between rigidity and impact resistance. (However, the total weight of each of the polypropylene resin (A), the elastomer (B), and the inorganic filler (C) is 100 parts by weight).

  The inorganic filler (C) used in the present invention is not limited as long as it can improve rigidity. For example, calcium carbonate, barium sulfate, mica, crystalline calcium silicate, talc, magnesium sulfate fiber, and And a mixture thereof. Talc, magnesium sulfate fiber, or a mixture thereof is preferable.

  As the talc, hydrous magnesium silicate is preferably pulverized from the viewpoint of rigidity and heat resistance. The crystal structure of the molecule is a pyrophyllite type three-layer structure, and the talc is a stack of these structures. In particular, a flat plate shape obtained by finely pulverizing crystals to a unit layer level is preferable.

The average particle diameter of talc is preferably 3 μm or less from the viewpoint of mechanical properties such as rigidity and impact resistance. Here, the average particle diameter of talc is a 50% equivalent particle determined from an integral distribution curve measured by a sieving method after suspending in a water or alcohol dispersion medium using a heart sedimentation type particle size distribution analyzer. It means the diameter D _50.

  Talc may be used as it is, or various known silane coupling agents and titanium coupling agents for improving the interfacial adhesion with the polypropylene resin (A) and improving the dispersibility. Higher fatty acids, higher fatty acid esters, higher fatty acid amides, higher fatty acid salts, or those having a surface treated with other surfactants may be used.

  The average fiber length of the magnesium sulfate fiber is preferably 5 to 50 μm, more preferably 10 to 30 μm, from the viewpoint of mechanical properties such as rigidity and impact resistance.

  The average fiber diameter of the magnesium sulfate fiber is preferably 0.3 to 2 μm, more preferably 0.5 to 1 μm, from the viewpoint of mechanical properties such as rigidity and impact resistance.

  The content of the inorganic filler (C) used in the present invention is 2 to 30 parts by weight, preferably 5 to 30 parts by weight, more preferably 10 to 30 parts by weight (provided that the polypropylene resin is used). (A), elastomer (B), and the total weight of each of the inorganic fillers (C) are 100 parts by weight). If the content of the inorganic filler (C) is less than 2 parts by weight, the rigidity may be reduced. If it exceeds 30 parts by weight, the impact strength may be insufficient, and the appearance is also deteriorated. There are things to do.

  The carbon black (D) used in the present invention is a carbon black having a pH of 3 or less, and preferably 2.5 or less from the viewpoint of color unevenness. The method for measuring the pH of carbon black is a method performed in accordance with the method described in JIS K6221-1982.

  The average particle diameter of carbon black (D) is preferably 50 nm or less, more preferably 30 nm or less, from the viewpoint of dispersibility.

  The content of the carbon black (D) used in the present invention is 0.000 based on a total of 100 parts by weight of the respective weights of the polypropylene resin (A), the elastomer (B), and the inorganic filler (C). It is 0001 to 1 part by weight, preferably 0.0005 to 0.5 part by weight, and more preferably 0.005 to 0.3 part by weight. When the amount is less than 0.0001 part by weight, the effect of improving the color unevenness may not be obtained. When the amount exceeds 1 part by weight, the fluidity may be insufficient or excessively uneconomical. .

  The zinc stearate (E) used in the present invention is preferably powdered zinc stearate.

  The content of zinc stearate (E) used in the present invention is 0 with respect to 100 parts by weight of the total weight of each of the polypropylene resin (A), the elastomer (B), and the inorganic filler (C). .2 to 1 part by weight, preferably 0.3 to 0.8 part by weight, and more preferably 0.4 to 0.7 part by weight. If the amount is less than 0.2 parts by weight, the effect of improving the color unevenness may not be obtained. If the amount exceeds 1 part by weight, it becomes excessive and uneconomical or the mold is contaminated during injection molding. There is.

  The method for producing a polypropylene resin composition of the present invention comprises a polypropylene resin (A), an elastomer (B), an inorganic filler (C), carbon black (D), and zinc stearate (E). And a kneading method using a kneader. Examples of the kneader include a single screw extruder, a twin screw extruder, a Banbury mixer, and a hot roll. And each of said component (A)-(E) may be simultaneously added to a kneader, may be knead | mixed, and may be added separately and kneaded.

  The kneading temperature is usually 170 to 250 ° C, preferably 190 to 230 ° C. The kneading time is usually 1 to 20 minutes, preferably 3 to 15 minutes.

  In addition to the above components (A) to (E), additives may be added to the polypropylene resin composition of the present invention as necessary. Examples of the additive include an antioxidant, Examples include ultraviolet absorbers, lubricants, pigments, antistatic agents, copper damage inhibitors, flame retardants, neutralizing agents, foaming agents, plasticizers, nucleating agents, antifoaming agents, and crosslinking agents.

  The injection-molded article of the present invention is an injection-molded article made of the polypropylene resin composition of the present invention. Examples of the injection molding method include generally known injection molding methods.

  The injection molded article of the present invention is preferably an automobile injection molded article, and examples thereof include door trims, back door trims, pillars, glow boxes, column covers, bumpers, side moldings, instrumental panels, consoles, and the like.

Hereinafter, the present invention will be described with reference to examples and comparative examples. Each component used in Examples and Comparative Examples is shown below.
(1) Polypropylene resin (A)
(Resin A-1) Ethylene-propylene block copolymer COSMOPLENE AZ864 (manufactured by The Polyolefin Company)

(Resin A-2) Polypropylene resin [Production method]
(1-1) Solid catalyst component (I)
After a 200 LSUS reaction vessel equipped with a stirrer was replaced with nitrogen, 80 L of hexane, 6.55 mol of tetrabutoxytitanium, 2.8 mol of diisobutyl phthalate, and 98.9 mol of tetraethoxysilane were added to obtain a uniform solution. Next, 51 L of a diisobutyl ether solution of butyl magnesium chloride having a concentration of 2.1 mol / L was gradually added dropwise over 5 hours while keeping the temperature in the reaction vessel at 5 ° C. After completion of the dropping, the mixture was stirred at 5 ° C. for 1 hour and further at room temperature for 1 hour, then solid-liquid separation was performed at room temperature, and washing was repeated 3 times with 70 L of toluene. Subsequently, after adjusting the amount of toluene so that a slurry density | concentration might be 0.2 Kg / L, it stirred at 105 degreeC for 1 hour. Then, it cooled to 95 degreeC, 47.6 mol of diisobutyl phthalates were added, and reaction was performed at 95 degreeC for 30 minutes. After the reaction, it was separated into solid and liquid and washed twice with toluene. Next, after adjusting the amount of toluene so that the slurry concentration becomes 0.4 kg / L, 3.1 mol of diisobutyl phthalate, 8.9 mol of n-dibutyl ether and 274 mol of titanium tetrachloride are added, and at 105 ° C. for 3 hours. Reaction was performed. After completion of the reaction, the solid and liquid were separated at the same temperature, and then washed twice with 90 L of toluene at the same temperature. After adjusting the amount of toluene so that the slurry concentration became 0.4 kg / L, 8.9 mol of n-dibutyl ether and 137 mol of titanium tetrachloride were added, and the reaction was carried out at 105 ° C. for 1 hour. After the completion of the reaction, solid-liquid separation was performed at the same temperature, followed by washing with 90 L of toluene three times at the same temperature, and further washing with 70 L of hexane three times, followed by drying under reduced pressure to obtain 11.4 kg of a solid catalyst component. The solid catalyst component contained 1.83% by weight of titanium atoms, 8.4% by weight of phthalate ester, 0.30% by weight of ethoxy groups, and 0.20% by weight of butoxy groups. This solid catalyst component is hereinafter referred to as solid catalyst component (I).

(1-2) Prepolymerization In a SUS autoclave with a 3L stirrer, hexane which has been sufficiently dehydrated and degassed with 25 mmol / L of triethylaluminum (hereinafter abbreviated as TEA) and t-butyl-n-propyldimethoxysilane as an electron donor component (Hereinafter abbreviated as tBunPrDMS) tBunPrDMS / TEA = 0.1 (mol / mol) and 15 g / L of the solid catalyst component (I) were added, and 1 g / L of propylene was added per solid catalyst while maintaining a temperature of 15 ° C. or lower. The prepolymerization was carried out by continuously feeding until g was reached. The obtained prepolymer slurry was transferred to a diluting tank equipped with a stirrer made of 120LSUS, diluted by adding sufficiently purified liquid butane, and stored at a temperature of 10 ° C. or lower.

(1-3) Main polymerization In a polymerization tank equipped with a stirrer made of 300 LSUS, 35 kg / h of liquefied propylene was supplied so as to maintain a polymerization temperature of 60 ° C. and a slurry amount of 95 L, and the ethylene concentration in the gas phase part was reduced to 2.8 vol%. Ethylene was supplied so that it was maintained, TEA was supplied at 51 mmol / h, tBunPrDMS was supplied at 5 mmol / h, and the prepolymer slurry prepared in the above (1-2) was supplied as a solid catalyst component at 1.0 g / h, and substantially hydrogen was supplied. Propylene-ethylene continuous copolymerization was carried out in the absence of A to obtain a polymer of 6.1 kg / h. The obtained polymer was continuously transferred to the second tank without being deactivated. The second tank is a fluidized bed gas phase reactor equipped with a stirrer made of SUS having an internal volume of 1 m ^{3 so} that the polymerization temperature is 70 ° C., the polymerization pressure is 1.8 MPa, and the ethylene concentration in the gas phase is maintained at 1.9 vol%. Propylene and ethylene are continuously supplied, and continuous gas phase polymerization is continued with the polymer containing the solid catalyst component transferred from the first tank in the substantial absence of hydrogen, and a polymer of 15.7 kg / h is obtained. Got. The polymer component polymerized in the first tank and the second tank corresponds to the first segment, the intrinsic viscosity [η] is 8.7 dl / g, the ethylene content is 3.5% by weight, and the melting temperature. The peak was 144.8 ° C. Subsequently, the obtained polymer was continuously transferred to the third tank without being deactivated. The third tank is a propylene so as to maintain a polymerization temperature of 85 ° C., a polymerization pressure of 1.4 MPa, and a hydrogen concentration in the gas phase of 11.7 vol% in a gas phase fluidized bed reactor with an internal volume of 1 m ^{3 and} a SUS stirrer. Then, 25.6 Kg / h of polymer was obtained by continuously supplying hydrogen and continuing continuous gas phase polymerization of propylene with the polymer containing the solid catalyst component supplied from the second tank. The polymer component polymerized in the third tank corresponds to the second segment, and the polymer obtained from the first tank through the third tank is a polypropylene resin (resin consisting of the first segment and the second segment) A-2), and its intrinsic viscosity [η] was 5.7 dl / g. From the above results, the polymerization amount in the first tank + second tank and the polymer ratio in the third tank is 61:39, and the intrinsic viscosity [η] of the polymer polymerized in the third tank is It was determined to be 0.9 dl / g.

(2) Elastomer (B)
(B-1) Engage EG8200 made of DuPont Dow elastomer
(B-2) Mitsui Chemicals, Toughmer A4050

(3) Inorganic filler (C)
Talc, Hayashi Kasei, MW HS-T

(4) Carbon black (D)
(D-1) pH = 2.5, particle size 13 nm
(D-2) pH = 7.5, particle size 16 nm
(D-3) pH = 3.5, particle size 24 nm
(D-4) pH = 9.5, particle size 16 nm

(5) Zinc stearate (E)
Zinc stearate made by Nippon Oil

The measuring method of the physical property of the resin component and composition used by the Example and the comparative example was shown below.
(1) Melt flow rate (MFR, unit: g / 10 minutes)
The measurement was performed according to the method defined in JIS-K-6758. Unless otherwise specified, the measurement temperature was 230 ° C. and the load was 2.16 kg.

(2) Flexural modulus (FM, unit: MPa)
The measurement was performed according to the method defined in JIS-K-7203. Using a test piece having a thickness of 6.4 mm and a span length of 100 mm formed by injection molding, the load speed was 2.0 mm / min and the measurement temperature was 23 ° C.

(3) Izod impact strength (Izod, unit: KJ / m ² )
The measurement was performed according to the method defined in JIS-K-7110. The measurement temperature was measured at 23 ° C. using a notched test piece which was formed by injection molding and had a thickness of 6.4 mm and was notched after molding.

(4) Heat distortion temperature (HDT, unit: ° C)
Using a test piece molded by injection molding, measurement was performed according to the method defined in JIS-K-7207. The fiber stress was measured at 1.82 MPa.

(5) Rockwell hardness (HR)
The measurement was performed according to the method defined in JIS-K-7202. It measured using the test piece which was shape | molded by injection molding and whose thickness is 3.0 mm. The measured value was displayed on the R scale.

(6) Intrinsic viscosity (unit: dl / g)
Using a Ubbelohde viscometer, reduced viscosities were measured at three concentrations of 0.1, 0.2 and 0.5 g / dl. Intrinsic viscosity is calculated according to the calculation method described in “Polymer solution, polymer experiment 11” (published by Kyoritsu Shuppan Co., Ltd.), page 491. That is, the reduced viscosity is plotted against the concentration, and the concentration is extrapolated to zero. Obtained by extrapolation.
The crystalline polypropylene was measured at a temperature of 135 ° C. using tetralin as a solvent.

(6-1) Intrinsic viscosity of crystalline ethylene-propylene block copolymer (6-1a) Intrinsic viscosity of propylene homopolymer portion (first segment): [η] _P
The intrinsic viscosity of the propylene homopolymer portion, which is the first segment of the crystalline ethylene-propylene block copolymer: [η] _P is propylene from the polymerization tank after the polymerization of the propylene homopolymer as the first step during its production. The homopolymer was taken out, and [η] _P of the taken out propylene homopolymer was measured and determined.

(6-1b) Intrinsic viscosity of ethylene-propylene random copolymer portion (second segment): [η] _EP
The intrinsic viscosity of the ethylene-propylene random copolymer portion, which is the second segment of the crystalline ethylene-propylene block copolymer: [η] _EP is the intrinsic viscosity of the propylene homopolymer portion: [η] _P and ethylene-propylene The intrinsic viscosity of the entire block copolymer: [η] _T was measured, and the weight ratio of the ethylene-propylene random copolymer portion to the entire crystalline ethylene-propylene block copolymer: X Asked.
[η] _EP = [η] _T / X− (1 / X−1) [η] _P
[η] _P : Intrinsic viscosity of the propylene homopolymer part (dl / g)
[η] _T : Intrinsic viscosity of the entire block copolymer (dl / g)

(6-1c) Weight ratio of ethylene-propylene random copolymer portion to the whole crystalline ethylene-propylene block copolymer: X
Weight ratio of ethylene-propylene random copolymer portion to the entire crystalline ethylene-propylene block copolymer: X is the heat of crystal fusion of the propylene homopolymer portion (first segment) and the entire crystalline ethylene-propylene block copolymer Was measured and calculated by the following formula. The amount of crystal melting heat was measured by suggestive scanning thermal analysis (DSC).
X = 1− (ΔH _f ) _T / (ΔH _f ) _P
(ΔH _f ) _T : heat of fusion of the entire block copolymer (cal / g)
(ΔH _f ) _P : heat of fusion of propylene homopolymer part (cal / g)

(7) Ethylene content of ethylene-propylene random copolymer portion in crystalline ethylene-propylene block copolymer: (C ₂ ′) _EP
The ethylene content of the ethylene-propylene random copolymer portion of the crystalline ethylene-propylene block copolymer: (C ₂ ′) _EP is the ethylene content of the entire crystalline ethylene-propylene block copolymer (C ₂ ) by infrared absorption spectroscopy. ₂ ') _T (wt%) was measured and calculated using the following formula.
(C ₂ ') _EP = (C ₂ ') _T / X
(C ₂ ′) _T : ethylene content (% by weight) of the entire block copolymer
(C ₂ ') _EP : ethylene content (% by weight) of ethylene-propylene random copolymer portion
X: Weight ratio of the ethylene-propylene random copolymer portion to the entire crystalline ethylene-propylene block copolymer

(8) Isotactic pentad fraction The isotactic pentad fraction is defined as A.I. The method published in Macromolecules, Vol. 6, 925 (1973) by Zambelli et al., Ie, isotactic linkage in pentad units in a polypropylene molecular chain measured using ¹³ C-NMR, in other words In other words, it is the fraction of propylene monomer units at the center of a chain in which five consecutive propylene monomer units are meso-bonded. However, the assignment of the NMR absorption peak was performed based on Macromolecules, Vol. 8, 687 (1975), which was subsequently published.
Specifically, the isotactic pentad fraction was measured as the area fraction of the mmmm peak in the total absorption peak in the methyl carbon region of the ¹³ C-NMR spectrum.
By this method, NPL standard material CRM No. of NATIONAL PHYSICAL LABORATORY, UK It was 0.944 when the isotactic pentad fraction of M19-14 Polypropylene PP / MWD / 2 was measured.

(9) Molecular weight distribution (Q value)
Gel permeation chromatography (GPC) was measured under the following conditions.

GPC: Waters 150C type Column: Showa Denko Shodex 80 MA 2 Sample amount: 300 μl (polymer concentration 0.2 wt%)
Flow rate: 1 ml / min Temperature: 135 ° C
Solvent: o-dichlorobenzene A standard curve of elution volume and molecular weight was prepared using standard polystyrene manufactured by Toyo Styrene Co., Ltd. Using the calibration curve, the polystyrene-equivalent weight average molecular weight and number average molecular weight of the specimen were determined, and the Q value, which is a measure of the molecular weight distribution, was calculated from the weight average molecular weight (Mw) / number average molecular weight (Mn).

(10) Appearance (10-1) Color unevenness evaluation Appearance is visually observed using a 105 × 135 × 2 mm flat plate molded by injection molding, and good (◯) and bad (×) are determined according to the following criteria. Was done.
Good: When streaky color unevenness did not occur in the molded product, it was judged as good (◯).
Defect: When streaky color unevenness occurred in the molded product, it was judged as defective (x).

(10-2) Flow Mark Appearance Appearance was visually observed using a 100 × 400 × 3 mm test piece molded by injection molding, and good (◯) and bad (×) were determined according to the following criteria. .
Good: When a striped pattern-like appearance defect partially occurred in the molded product, it was judged as good (◯).
Defect: When a striped pattern-like appearance defect occurred on almost the entire surface of the molded product, it was judged as a defect (x).

[Manufacture of injection molded products (1)]
The test piece which is an injection-molded article for evaluating physical properties of the above (2), (3), (4), (5) and (10-2) was prepared according to the following method.
The composition is dried in a hot air dryer at 120 ° C. for 2 hours and then injected at a molding temperature of 220 ° C., a mold cooling temperature of 50 ° C., an injection time of 15 seconds, and a cooling time of 30 seconds using an IS150E-V type injection molding machine manufactured by Toshiba Machine. Molding was performed to obtain a test piece as an injection-molded body.

[Manufacture of injection-molded bodies (2)]
The test piece which is the injection molded product for evaluating color unevenness (10-1) was prepared according to the following method.
After drying the composition at 120 ° C. for 2 hours with a hot air dryer, using a NEOMAT 150 / 75A SYCAP type injection molding machine manufactured by Sumitomo Heavy Industries, the molding temperature is 220 ° C., the mold cooling temperature is 55 ° C., the injection time is 10 seconds, and the cooling time is 15 seconds. Injection molding was performed to obtain a test piece that was an injection-molded body.

[Production of polypropylene resin composition]
The polypropylene fat composition was produced according to the following method.
Each component is weighed in a predetermined amount and uniformly premixed with a Henschel mixer or tumbler, and then the extrusion rate is 30 to 50 kg / hr using a twin-screw kneading extruder (TEX44SS 30BW-2V type manufactured by Nippon Steel Works). Then, the composition was prepared by kneading and extruding at 350 rpm with a screw rotation speed under vent suction.

  Table 1 shows the content (parts by weight) of each component in the polypropylene-based resin compositions of Examples 1 to 4, and Table 2 shows the content (parts by weight) of each component in the polypropylene-based fat compositions of Comparative Examples 1-6. )showed that.

  Table 3 shows the physical properties of the polypropylene resin compositions of Examples 1 to 4 and Comparative Examples 1 to 3 and the physical properties of the injection-molded articles obtained using the compositions, and Table 4 shows Examples 1 to 4. And the result of the external appearance of the injection molded object obtained using the polypropylene resin composition of Comparative Examples 1-6 was shown.

Examples 1 to 4 are polypropylene-based resin compositions that satisfy the requirements of the present invention, which are excellent in rigidity, impact strength, and fluidity, have no color unevenness, and have a good appearance. I understand that.
On the other hand, Comparative Example 1 did not use zinc stearate which is a requirement of the present invention, and Comparative Example 2 does not satisfy the content of zinc stearate which is a requirement of the present invention. Comparative Examples 3, 5 and 6 do not satisfy the pH of carbon black which is a requirement of the present invention, and Comparative Example 4 has the content of zinc stearate and the pH of carbon black which are requirements of the present invention. It is not satisfactory, color unevenness occurs in the injection molded product, and it can be seen that the appearance is poor.

Claims (4)

61-97 parts by weight of a polypropylene resin (A),
1 to 9 parts by weight of elastomer (B),
Containing 2 to 30 parts by weight of inorganic filler (C) (provided that the total weight of (A), (B) and (C) is 100 parts by weight),
For a total of 100 weights of (A), (B) and (C),
0.0001 to 1 part by weight of carbon black (D) having a pH of 3 or less,
A polypropylene resin composition containing 0.2 to 1 part by weight of zinc stearate (E). The polypropylene resin composition according to claim 1, wherein the polypropylene resin (A) is a resin containing the following polypropylene resin (A-1) and the following polypropylene resin (A-2).
Polypropylene resin (A-1): A resin excluding polypropylene resin (A-2).
Polypropylene resin (A-2):
60-80% by weight of a first segment which is a propylene homopolymer or an ethylene-propylene random copolymer, and the intrinsic viscosity of a 135 ° C. tetralin solution is 5 dl / g or more,
A resin (provided that the propylene homopolymer or the ethylene-propylene random copolymer is 20 to 40% by weight of a second segment having an intrinsic viscosity of a 135 ° C. tetralin solution of 0.8 to 1.2 dl / g, provided that The total amount of (A-2) is 100% by weight).   The polypropylene according to claim 2, wherein the content of the polypropylene resin (A-1) is 56 to 96.9 parts by weight, and the content of the polypropylene resin (A-2) is 0.1 to 5 parts by weight. -Based resin composition. (However, the total weight of (A), (B) and (C) is 100 parts by weight)   An injection-molded article comprising the polypropylene resin composition according to any one of claims 1 to 3.