JP2006225467A - Polypropylene-based resin composition and molded article thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polypropylene-based resin composition having excellent balance between light weight and rigidity, and also having excellent dimensional stability, flowability and recyclability of a heat source; and to provide a molded article thereof. <P>SOLUTION: The polypropylene-based resin composition comprises (A) 100 pts.wt. polypropylene resin, (B) 0.5-100 pts.wt. carbon fiber having >2 and ≤15 μm fiber diameter and 1-20 mm fiber length, and (C) 0.01-5 pts.wt. nucleating agent selected from the group consisting of a metal salt of an aromatic carboxylic acid and the like. The polypropylene resin of the component (A) is selected from a propylene homopolymer (a) having 1.5-2.5 die swell ratio, 7-13 Mw/Mn, ≥96% isotactic pentad fraction, and 20-100 g/10 min MFR, and a polypropylene block copolymer (b) comprising the propylene homopolymer (a) and a propylene copolymer obtained by copolymerizing propylene and an α-olefin. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polypropylene resin composition excellent in mechanical strength and light weight, and a molded body thereof. More specifically, the present invention relates to a polypropylene resin composition excellent in mechanical strength, dimensional stability, balance between fluidity and light weight, and heat source recyclability, and a molded product thereof.

Polypropylene is easy to mold and has an excellent balance between lightness and mechanical properties, and is therefore widely used in various industrial parts such as daily life materials and automobile interior and exterior parts. In particular, the range of use of automobile interior and exterior parts such as bumpers, instrument panels, door trims, and pillars has been steadily expanding in recent years.
Polypropylene for industrial parts is devised to incorporate inorganic fillers such as talc, mica and glass fiber in order to improve mechanical strength such as rigidity and heat resistance, and talc is widely used as the most representative inorganic filler. Has been. However, since the aspect ratio of talc is less than 100 at the maximum, a large amount of blending is necessary to develop the required mechanical strength, and the specific gravity of the polypropylene composition blended with talc is high. Therefore, the reinforcement efficiency is not sufficient.

For this reason, a method of blending a fibrous filler such as glass fiber, whisker, or carbon fiber having a high aspect ratio is known for applications that require higher rigidity (see, for example, Patent Document 1). Among these, carbon fiber not only provides higher reinforcement efficiency (that is, balance between rigidity and lightness) than glass fiber and whiskers, but also is an incinerator for heat source recycling because it is an organic substance. During the treatment, there is no burning residue as an incineration residue, and the reinforcing material is excellent in heat source recyclability.
From these viewpoints, the present inventors have proposed a polypropylene-based resin composition in which a polypropylene having a specific structure and a carbon fiber having a specific structure, excellent in crystallinity and impact properties, are combined (for example, However, in subsequent studies, it has been found that the balance between rigidity and light weight and dimensional stability are not always sufficient.
In addition, the present inventors have proposed a polypropylene-based resin composition that is made of polypropylene, carbon fiber, and inorganic filler having a specific structure and is extremely excellent in rigidity and dimensional stability (see, for example, Patent Document 3). ) Realizes extremely high rigidity and good dimensional stability, but increases the specific gravity, incineration residue, and anisotropy of dimensional change due to the inorganic filler compounding, so it is lightweight, dimensional accuracy, and heat source recyclability. From this point of view, it was necessary to make further improvements.
JP 2001-81246 A Japanese Patent Application No. 2003-436850 Japanese Patent Application No. 2004-046554

  The present invention eliminates the drawbacks of the prior art as described above, is excellent in the balance between lightness and rigidity, and further has excellent dimensional stability, fluidity, and heat source recyclability, and molding thereof. The challenge is to provide a body.

  In order to solve the above problems, the present inventors have made extensive studies on a polypropylene-based resin composition excellent in the balance between lightness and rigidity. As a result, the molecular structure and crystal structure of the homopolymer portion are controlled with a specific polypropylene. The present inventors completed the present invention by finding that a composite of a carbon fiber having a structure and a nucleating agent can provide a polypropylene resin composition excellent in balance between lightness and rigidity, dimensional stability, and appearance. .

That is, according to the first invention of the present invention, (B) 0.5 to 100 parts by weight of carbon fiber and (C) nucleating agent 0.01 to 5 with respect to 100 parts by weight of the following (A) polypropylene resin. A polypropylene resin composition characterized by containing parts by weight is provided.
(A) Polypropylene resin: The die swell ratio is 1.5 to 2.5, and the ratio (Mw / Mn) of the weight average molecular weight Mw and the number average molecular weight Mn measured by gel permeation chromatography (GPC) is 7 to 7 13. Propylene homopolymer (a) having an isotactic pentad fraction of 96% or more and a melt flow rate (measured at 230 ° C. according to JIS K7210, hereinafter referred to as MFR) of 20 to 100 g / 10 min. Or the propylene content obtained by copolymerizing the propylene homopolymer (a), propylene and an α-olefin having 2 to 12 carbon atoms (excluding 3), and the MFR is 0.001 to 6 g. Propylene block copolymer having a MFR of 5 to 80 g / 10 min (b) Polypropylene resin selected from (B) Carbon fiber: Carbon fiber having a fiber diameter of more than 2 μm and not more than 15 μm and a fiber length of 1-20 mm (C) Nucleating agent: Aromatic carboxylate metal salt, organophosphate metal Nucleating agent selected from the group consisting of salts and metal salts of rosin acid

  According to the second invention of the present invention, in the first invention, the propylene homopolymer (a) is a polypropylene homopolymer produced by multistage polymerization. Is provided.

  According to the third invention of the present invention, in the second invention, the propylene homopolymer (a) contains 50 to 95% by weight of a propylene polymer having an MFR of 200 to 1000 g / 10 min. A polypropylene resin composition is provided.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the metal salt as the nucleating agent is any one of aluminum and sodium. A polypropylene resin composition is provided.

According to the fifth aspect of the present invention, in any one of the first to fourth aspects, the MFR is 0.1 to 15 g / 10 min and the density is 0 with respect to 100 parts by weight of the (A) polypropylene resin. Provided is a polypropylene resin composition comprising 1 to 50 parts by weight of at least one thermoplastic elastomer (D) selected from .850 to 0.910 g / cm ³ ethylene elastomer or styrene elastomer. Is done.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the relationship between the density and the bending elastic modulus satisfies the following relational expression (1). The polypropylene-type resin composition of any one of -5 is provided.
FM> 42ρ-36000 (1)
(Where FM represents the flexural modulus (unit: MPa), and ρ represents the density (unit: kg / m ³ ))

  According to the seventh invention of the present invention, the polypropylene resin composition of any one of the first to sixth inventions is molded from the group consisting of injection molding, compression molding, extrusion molding, and injection compression molding. A molded body formed by the method is provided.

According to the eighth aspect of the present invention, there is provided a molded body characterized in that, in the seventh aspect, the relationship between the density and the bending elastic modulus satisfies the following relational expression (1).
FM> 42ρ-36000 (1)
(Where FM represents the flexural modulus (unit: MPa), and ρ represents the density (unit: kg / m ³ ))

  According to the ninth aspect of the present invention, there is provided a vehicle component, a residential component, or a home appliance component comprising the seventh or eighth molded body.

  The polypropylene resin composition of the present invention is a polypropylene resin composition excellent in the balance between lightness and rigidity, and further excellent in dimensional stability, fluidity, and heat source recyclability. In use, it is a useful material.

Hereinafter, the present invention will be described in detail.
1. Polypropylene Resin Composition (1) Constituent Components The polypropylene resin composition of the present invention comprises (A) polypropylene resin, (B) carbon fiber, (C) nucleating agent, and (D) thermoplastic elastomer as required. Contains the ingredients. Below, each component and its composition ratio are demonstrated in detail.

(A) Polypropylene resin (A) Polypropylene resin used in the polypropylene resin composition of the present invention is a polypropylene homopolymer (a), or (a), propylene and 2 to 12 carbon atoms (excluding 3). It is any resin of the propylene block copolymer (b) containing the propylene copolymer formed by copolymerizing an α-olefin.

(A) Propylene homopolymer The propylene homopolymer (a) used in the present invention has a die swell ratio of 1.5 to 2.5, preferably 1.5 to 2.4, more preferably 1.55 to 2. .35.
When the die swell ratio deviates from the above range, the appearance at the time of injection molding such as a flow mark is deteriorated, and the anisotropy of dimensional change such as molding shrinkage rate and linear expansion coefficient is not preferable.
Here, the die swell ratio is determined by loading polypropylene in a heating cylinder at 190 ° C., holding it heated for 6 minutes, and extruding it from an orifice having a diameter of 1 mm and a length of 8 mm at a speed of 0.1 g / min. It is a value obtained by measuring and calculating by strand diameter / orifice diameter.

Further, the ratio (Mw / Mn) of the weight average molecular weight Mw and the number average molecular weight Mn measured by gel permeation chromatography (GPC) of the component (a) is 7 to 13, preferably 8 to 12, more preferably. Is 8.5 to 11.5. When Mw / Mn deviates from the above range, not only the appearance at the time of injection molding such as a flow mark is deteriorated, but the anisotropy of dimensional change such as molding shrinkage and linear expansion coefficient is increased. Since the effect of the nucleating agent component blended in is not sufficiently obtained, it is not preferable.
Here, Mw / Mn is the ratio of the weight average molecular weight to the number average molecular weight measured by GPC. Specifically, measurement is performed under the following conditions using GPC.
Apparatus: Waters HLC / GPC 150C
Column temperature: 135 ° C
Solvent: o-dichlorobenzene Flow rate: 1.0 ml / min
Column: manufactured by Tosoh Corporation GMH _HR- H (S) HT 60 cm × 1
Injection volume: 0.15 ml (no filtration treatment)
Solution concentration: 5 mg / 3.4 ml
Sample preparation: Use o-dichlorobenzene to prepare a 5 mg / 3.4 ml solution and dissolve at 140 ° C. for 1 to 3 hours.
Calibration curve: A standard polystyrene sample is used.
Calibration curve order: primary PP molecular weight: PS × 0.639

Furthermore, the isotactic pentad fraction of component (a) is 96% or more, preferably 98.0 to 99.5%, more preferably 98.5 to 99.5%. If the isotactic pentad fraction is less than 96%, the balance between lightness, rigidity and heat resistance is inferior, which is not preferable.
Here, the isotactic pentad fraction is the isotactic ratio of pentad units in a polypropylene molecular chain measured by the method described in Macromolecules, 6, 925 (1973), that is, the method using ¹³ C-NMR. The tick fraction. In other words, the isotactic pentad fraction is the fraction of propylene monomer units at the center of a chain in which five propylene monomer units are connected and meso-bonded. However, peak assignment was performed based on the method described in Macromolecules, 8, 687 (1975). Specifically, the isotactic pentad unit is measured as the intensity fraction of the mmmm peak in the total absorption peak in the methyl carbon region of the ¹³ C-NMR spectrum.

Furthermore, the MFR of component (a) is 20 to 100 g / 10 minutes, preferably 24 to 80 g / 10 minutes, more preferably 25 to 75 g / 10 minutes. When the MFR is less than 20 g / 10 minutes, the fluidity is inferior, which is not preferable, and when it exceeds 100 g / 10 minutes, the impact properties and mechanical strength are inferior.
Here, MFR is a value measured at 230 ° C. and a 21.18 N load in accordance with JIS-K7210.

The production method of the propylene homopolymer (a) used in the present invention is not particularly limited, and is appropriately selected from conventionally known polymerization methods using a polymerization catalyst for polypropylene.
As the propylene polymerization catalyst, a highly stereoregular catalyst is usually used. For example, a catalyst comprising a combination of a titanium trichloride composition obtained by reducing titanium tetrachloride with an organoaluminum compound and further treating with various electron donors and electron acceptors, an organoaluminum compound and an aromatic carboxylic acid ester ( JP-A 56-1000080, JP-A 56-120712, JP-A 58-104907), supported catalyst in which titanium tetrachloride and various electron donors are contacted with magnesium halide ( JP-A-57-63310, JP-A-63-43915, and JP-A-63-83116).

As the polymerization method, propylene is homopolymerized or propylene is applied in the presence of the propylene polymerization catalyst by applying a production process such as a gas phase polymerization method, a liquid phase bulk polymerization method, a slurry polymerization method, or a combination thereof. And a small amount of α-olefin are copolymerized. A slurry polymerization method and a gas phase polymerization method are preferred.
Single-stage polymerization or multi-stage polymerization in which polymerization is performed successively under the same or different polymerization conditions may be used. In order to obtain a propylene homopolymer having the above-described die swell ratio, molecular weight distribution (Mw / Mn), and melt characteristics (MFR), a method of multistage polymerization is preferred. Examples of the multistage polymerization method include a multistage polymerization method including the following steps (1) and (2), or a two-stage polymerization method based on the steps (1) and (2).

Step (1): Propylene is polymerized in the presence of hydrogen as a molecular weight regulator. This is to suppress the formation of a polymer having a too high molecular weight. Hydrogen is added so that the MFR of the polymer obtained in the first polymerization step is 200 to 1000 g / 10 minutes, preferably 300 to 900 g / 10 minutes. The hydrogen concentration is usually selected from the range of 0.5 to 40%, preferably 1 to 30%. The polymerization temperature is usually selected from the range of 40 to 90 ° C., and the pressure is in the range of 2 × 10 ^{5 to} 35 × 10 ⁵ Pa. The amount of the polymer obtained in this step (1) is usually adjusted to 50 to 95% by weight, preferably 60 to 90% by weight of the total polymerization amount. When the amount of the polymer produced in the step (1) is less than 50% by weight, the amount of the high molecular weight polypropylene polymer produced in the step (2) is too much, and the dimensional stability of the resin composition of the present invention Since the appearance is inferior, it is not preferable.

Step (2): A step for obtaining a high molecular weight polypropylene polymer. In particular, the die shell ratio of the propylene homopolymer (a) can be controlled by the molecular weight and amount of the polypropylene polymer obtained in this step. In order to polymerize a high molecular weight polypropylene polymer, it is preferable to polymerize in a hydrogen atmosphere as low as possible or in a state where hydrogen is not substantially present. The polymerization is subsequently carried out in the presence of the polypropylene produced in step (1) and a catalyst. The polymerization temperature is usually selected from the range of 40 to 90 ° C. and the pressure of 2 × 10 ^{5 to} 35 × 10 ⁵ Pa. The amount of the polymer obtained in this step (2) is adjusted to be 5 to 50% by weight, preferably 10 to 40% by weight of the total polymerization amount.
Any combination may be adopted as long as the physical properties of the resulting polymer can be adjusted to the above-mentioned range by combining the other steps with the step (1) and the step (2) as necessary. .

(B) Propylene block copolymer The propylene block copolymer (b) that can be used in the present invention comprises the above-mentioned propylene homopolymer (a) portion, propylene, and 2 to 12 carbon atoms (excluding 3). A propylene block copolymer comprising a propylene content of 20 to 80% by weight and an MFR of 0.001 to 6 g / 10 min, which is obtained by copolymerizing an α-olefin.
Examples of the α-olefin having 2 to 12 carbon atoms (excluding 3) include ethylene, butene, pentene, hexene, and octene.

The propylene content in the propylene copolymer portion is 20 to 80% by weight, preferably 30 to 70% by weight, more preferably 35 to 70% by weight. When the propylene content deviates from the above range, the dispersibility of the copolymer portion is deteriorated or the low temperature brittleness is deteriorated.
Here, the propylene content can be measured by a conventionally known conventional method using ¹³ C-NMR method.

The MFR of the propylene copolymer portion is 0.001 to 6 g / 10 minutes, preferably 0.005 to 3 g / 10 minutes, and more preferably 0.01 to 3 g / 10 minutes. When the MFR of the copolymer part deviates from the above range, it is not preferable because the dispersibility of the copolymer part deteriorates or the impact property decreases.
The MFR (MFRb) of the propylene copolymer part is the MFR (MFRa) and ratio (Wa (wt%)) of the propylene homopolymer (a) and the MFR (MFR) and propylene copolymer part of the propylene block copolymer From the ratio (Wb (% by weight)), the following equation can be calculated using a logarithmic additive equation.
100 × LOG (MFR) = Wa × LOG (MFRa) + Wb × LOG (MFRb)

  The MFR of the propylene block copolymer (b) is 5 to 80 g / 10 minutes, preferably 10 to 70 g / 10 minutes, and more preferably 15 to 65 g / 10 minutes. When the MFR of the propylene block copolymer deviates from the above range, the fluidity, appearance, impact properties, etc. are inferior.

  The proportion of the propylene homopolymer (a) and the propylene copolymer in the propylene block copolymer (b) is such that the propylene homopolymer is 50 to 95 wt%, preferably 55 to 90 wt%, more preferably. It is 60 to 88% by weight, and the propylene copolymer is 5 to 50% by weight, preferably 10 to 45% by weight, more preferably 12 to 40% by weight.

  The propylene block copolymer (b) can be obtained by a production method including a step of producing a series of propylene homopolymers (a) and a step of producing a propylene copolymer (regardless of before and after). The process for producing the propylene homopolymer (a) is as described above. The process for producing the propylene copolymer can be produced by adjusting the supply ratio of propylene and α-olefin and the supply amount of the molecular weight regulator so as to obtain a predetermined propylene content and MFR.

  In addition, the polypropylene resin (A) component used by this invention may contain the polypropylene which does not have the said characteristic in the range which does not impair the effect of this invention.

(B) Carbon fiber The (B) carbon fiber used in the polypropylene resin composition of the present invention has a fiber diameter of more than 2 μm and 15 μm or less, preferably 3 μm to 12 μm, more preferably 4 μm to 10 μm. When the fiber diameter is 2 μm or less, the rigidity of the fiber is remarkably reduced, and when it exceeds 15 μm, the aspect ratio of the fiber (the ratio of length (L) to thickness (D): L / D) is reduced. This is not preferable because sufficient reinforcement efficiency such as rigidity and heat resistance cannot be obtained.
Here, the fiber diameter can be determined by cutting the fiber perpendicular to the fiber direction, observing the cross section under a microscope, measuring the diameter, and calculating the number average of the diameters of 100 or more fibers.

The carbon fiber (B) has a fiber length of 1 to 20 mm, preferably 2 to 15 mm, more preferably 3 to 10 mm. When the fiber length is less than 1 mm, the aspect ratio is low and sufficient reinforcement efficiency cannot be obtained. When the fiber length exceeds 20 mm, the workability and appearance are remarkably deteriorated.
Here, the fiber length can be obtained by measuring using a caliper or the like and calculating the number average of the fiber lengths of 100 or more fibers.

  As (B) carbon fiber used by the polypropylene resin composition of this invention, if the above-mentioned shape is satisfy | filled, a conventionally well-known carbon fiber can be used without a restriction | limiting in particular. Examples of the carbon fiber include PAN-based carbon fiber using polyacrylonitrile as a raw material, and pitch-based carbon fiber using pitch as a raw material. These carbon fibers can be used as so-called chopped carbon fibers obtained by cutting the fiber yarn into a desired length, and may be subjected to convergence treatment using various sizing agents as necessary. . Since the sizing agent used for the convergence treatment needs to be melted in melt kneading with the polypropylene resin, it is preferable that the sizing agent is melted at 200 ° C. or lower.

  Specific examples of such chopped carbon fibers include PAN-based carbon fibers, trade name “Torayca Chop” manufactured by Toray Industries, Inc., product name “Pyrofil (chop)” manufactured by Mitsubishi Rayon Co., Ltd., Toho Tenax ( The product name “Besfite (chop)”, etc. made by the company can be mentioned, and for pitch-based carbon fiber, the product name “Dialead” made by Mitsubishi Chemical Industries, Ltd., made by Osaka Gas Chemical Co., Ltd. Product names such as “Donna Carbo (chop)” and Kureha Chemical Co., Ltd. product name “Kureka Chop” can be listed.

  These carbon fiber components are combined with other components constituting the polypropylene resin composition of the present invention using a melt-kneading apparatus such as an extruder. During the melt-kneading, the carbon fiber components are combined. It is preferable to select a composite method that prevents excessive breakage. As a method for realizing this, for example, in melt kneading by an extruder, components other than the carbon fiber component are sufficiently melt kneaded, and then the carbon fiber component is removed from the complete melting position of the resin component by a side feed method or the like. Also, a method of feeding the convergent fibers while feeding from a downstream position and minimizing fiber breakage can be exemplified.

(C) Nucleating agent (C) The nucleating agent used in the polypropylene resin composition of the present invention is selected from the group consisting of aromatic carboxylic acid metal salts, organophosphate metal salts, and rosin acid metal salts. A nucleating agent that has a nucleating action on polypropylene. This nucleating action is an action of improving the crystallinity and rigidity of polypropylene by adding a nucleating agent.

As said aromatic carboxylic acid metal salt, pt-butyl aluminum benzoate etc. can be illustrated, for example.
Moreover, as said organophosphate metal salt, the compound represented by the following general formula (I) or general formula (II) can be illustrated, for example.
Formula (I):

  General formula (II):

In general formulas (I) and (II), R ₁ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ₂ , R ₃ , R ₄ , R ₅ , and R ₆ represent a hydrogen atom or carbon, respectively. An alkyl group having 1 to 12 atoms; M represents an alkali metal atom, an alkaline earth metal atom or a zinc atom; and p and q represent 1 or 2.

  Specific examples of the compound represented by the general formula (I) include sodium-2,2′-methylene-bis (4,6-di-t-butylphenyl) phosphate, sodium-2,2′-ethylidene- Bis (4,6-di-t-butylphenyl) phosphate, lithium-2,2′-methylene-bis- (4,6-di-t-butylphenyl) phosphate, lithium-2,2′-ethylidene-bis (4,6-di-t-butylphenyl phosphate, sodium-2,2′-ethylidene-bis (4-i-propyl-6-t-butylphenyl) phosphate, lithium-2,2′-methylene-bis ( 4-methyl-6-tert-butylphenyl) phosphate, calcium-bis [2,2′-thiobis (4-methyl-6-tert-butylphenyl) phosphate], calcium -Bis [2,2'-thiobis (4-ethyl-6-t-butylphenyl) phosphate], calcium-bis [2,2'-thiobis- (4,6-di-t-butylphenyl) phosphate], Magnesium-bis [2,2′-thiobis (4,6-di-t-butylphenyl) phosphate], magnesium-bis [2,2′-thiobis- (4-t-octylphenyl) phosphate], sodium-2 , 2'-butylidene-bis (4,6-di-methylphenyl) phosphate, sodium-2,2'-butylidene-bis (4,6-di-t-butylphenyl) phosphate, sodium-2,2'- t-octylmethylene-bis (4,6-di-methylphenyl) phosphate, calcium-bis- (2,2′-methylene-bis (4,6-di-t-butyl) Ruphenyl) phosphate), magnesium-bis [2,2′-methylene-bis (4,6-di-t-butylphenyl) phosphate], barium-bis [2,2′-methylene-bis (4,6-di) -T-butylphenyl) phosphate], sodium-2,2'-methylene-bis (4-methyl-6-t-butylphenyl) phosphate, sodium-2,2'-methylene-bis (4-ethyl-6- t-butylphenyl) phosphate, sodium (4,4? -dimethyl-5,6'-di-t-butyl-2,2'-biphenyl) phosphate, calcium-bis [(4,4'-dimethyl-6, 6'-di-t-butyl-2,2'-biphenyl) phosphate], sodium-2,2'-ethylidene-bis (4-m-butyl-6-t-butylphenyl) Sulfate, sodium-2,2′-methylene-bis (4,6-di-methylphenyl) phosphate, sodium-2,2′-methylene-bis (4,6-di-ethylphenyl) phosphate, potassium-2, 2′-ethylidene-bis (4,6-di-t-butylphenyl) phosphate, calcium-bis [2,2′-ethylidene-bis (4,6-di-t-butylphenyl) phosphate], magnesium-bis [2,2′-ethylidene-bis (4,6-di-t-butylphenyl) phosphate], barium-bis [2,2′-ethylidene-bis (4,6-di-t-butylphenyl) phosphate] , Aluminum-tris [2,2′-methylene-bis (4,6-di-t-butylphenyl) phosphate] and aluminum-tris [2,2 '-Ethylidene-bis (4,6-di-t-butylphenyl) phosphate] and a mixture of two or more thereof. Sodium-2,2'-methylene-bis (4,6-di-t-butylphenyl) phosphate is particularly preferable.

  Specific examples of the compound represented by the general formula (II) include sodium-bis (4-t-butylphenyl) phosphate, sodium-bis (4-methylphenyl) phosphate, sodium-bis (4-ethyl). Phenyl) phosphate, sodium-bis (4-i-propylphenyl) phosphate, sodium-bis (4-t-octylphenyl) phosphate, potassium-bis (4-t-butylphenyl) phosphate, calcium-bis (4-t -Butylphenyl) phosphate, magnesium-bis (4-t-butylphenyl) phosphate, lithium-bis (4-t-butylphenyl) phosphate, aluminum-bis (4-t-butylphenyl) phosphate and two or more thereof And the like. Sodium-bis (4-t-butylphenyl) phosphate is particularly preferable. Further, those described in JP-A-9-77919 and JP-A-9-10031 can also be suitably used.

Examples of the rosin acid metal salt include rosin acid sodium salt, rosin acid potassium salt, and rosin acid magnesium salt. The rosin acid metal salt is a reaction product of rosin acid and a metal compound, and includes both a mixture of a rosin acid metal salt and an unreacted rosin acid, and a rosin acid metal salt containing no unreacted rosin acid. means. Examples of the metal compound that reacts with rosin acid to form a metal salt include a compound having a metal element such as sodium, potassium, magnesium and the like and salt-forming with the rosin acid. And chlorides, nitrates, acetates, sulfates, carbonates and hydroxides. Various rosin acids such as gum rosin, tall oil rosin, wood rosin and other natural rosin, disproportionated rosin, hydrogenated rosin, dehydrogenated rosin, polymerized rosin, α, β-ethylenically unsaturated carboxylic acid modified rosin Examples include rosin, purified natural rosin, and purified modified rosin. Natural rosin usually contains multiple types of resin acids such as pimaric acid, sandaracopimalic acid, parastrinic acid, isopimaric acid, abietic acid, dehydroabietic acid, neoabietic acid, dihydropimaric acid, dihydroabietic acid, tetrahydroabietic acid, etc. It is.
Examples of the unsaturated carboxylic acid used for preparing the α, β-ethylenically unsaturated carboxylic acid-modified rosin include maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, citraconic acid, and acrylic acid. , Methacrylic acid, and the like.

Preferable examples of the rosin acid metal salt include compounds represented by the following general formulas (III) and (IV).
Formula (III):

  Formula (IV):

In the general formulas (III) and (IV), R ₇ , R ₈ , and R ₉ may be the same or different from each other, and each represents a hydrogen atom, an alkyl group, a cycloalkyl group, or an aryl group, and M is 1 to 1 The trivalent metal ion, r, is the same integer as the valence of the metal ion M, and is an integer of 1 to 3.

Specific examples of the alkyl group represented by R _{7 to} R ₉ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, various pentyl groups, various heptyl groups, Examples thereof include alkyl groups having 1 to 8 carbon atoms such as various octyl groups, and these groups may have a substituent such as hydroxyl group, carboxyl group, alkoxy group and halogen.
Specific examples of the cycloalkyl group represented by R _{7 to} R ₉ include cycloalkyl groups having 5 to 8 carbon atoms such as a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group, and these groups include a hydroxyl group, You may have substituents, such as a carboxyl group, an alkoxy group, and a halogen.
Examples of the aryl group of R _{7 to} R ₉ include an aryl group having 6 to 10 carbon atoms such as a phenyl group, a tolyl group, and a naphthyl group, and these groups include a hydroxyl group, a carboxyl group, an alkoxy group, It may have a substituent such as halogen.
In the above R _{7 to} R ₉ , a compound in which R ₇ is an isopropyl group and R ₈ and R ₉ are methyl groups is more preferable.

  M is a metal ion having 1 to 3 valences. Specifically, it is a monovalent metal ion such as lithium, sodium, potassium, rubidium or cesium, or divalent such as beryllium, magnesium, calcium, strontium, barium or zinc. And trivalent metal ions such as aluminum. Of these, monovalent or divalent metal ions are preferable, and sodium ions, potassium ions, and magnesium ions are preferable.

  Specific examples of the compound (III) include, for example, lithium dehydroabietate, sodium dehydroabietic acid, potassium dehydroabietic acid, beryllium dehydroabietic acid, magnesium dehydroabietic acid, calcium dehydroabietic acid, zinc dehydroabietic acid, zinc dehydroabieticin Examples thereof include metal salts of dehydroabietic acid such as aluminum acid. Among them, sodium dehydroabietic acid, potassium dehydroabietic acid, and magnesium dehydroabietic acid are preferably used.

  Specific examples of the compound (IV) include, for example, lithium dihydroabietate, sodium dihydroabietic acid, potassium dihydroabietic acid, beryllium dihydroabietic acid, magnesium dihydroabietic acid, calcium dihydroabietic acid, zinc dihydroabietic acid, zinc dihydroabieticin Dihydroabietic acid metal salts such as aluminum acid can be mentioned, and among them, sodium dihydroabietic acid, potassium dihydroabietic acid, and magnesium dihydroabietic acid are preferably used.

  Among such nucleating agents, aromatic carboxylic acid metal salts and organophosphate metal salts are particularly preferably used.

(D) Thermoplastic elastomer In the polypropylene resin composition of this invention, a thermoplastic elastomer (D) can be used as needed. The component (D) is an ethylene-based and / or styrene-based elastomer having an MFR of 0.1 to 15 g / 10 min and a density of 0.850 to 0.910 g / cm ³ .
When the MFR of the thermoplastic elastomer is less than 0.1 g / 10 minutes, the dispersibility of the thermoplastic elastomer is inferior, and when it exceeds 15 g / 10 minutes, the impact resistance and the low temperature brittleness are inferior. When the density of the thermoplastic elastomer deviates from the above range, the impact resistance and productivity are inferior.

  An ethylene-based elastomer is a copolymer obtained by copolymerizing ethylene and at least one other α-olefin, and the α-olefin copolymerized with ethylene generally has 3 to 8 carbon atoms. Specific examples include an ethylene / propylene copolymer, an ethylene / butene copolymer, and an ethylene / octene copolymer.

The styrene elastomer is a styrene hydrogenated block copolymer rubber having the following structure, and the content of the A segment having the polystyrene structure is preferably 1 to 25% by weight.
A-B or A-B-A
(However, A represents a polystyrene structural segment, and B represents a structural segment of ethylene / butene or ethylene / propylene)
If the content of the A segment is less than 1% by weight, it is practically not a styrenic elastomer, and if it exceeds 25% by weight, the compatibility with the polypropylene resin is remarkably lowered and sufficient dispersion cannot be obtained. Absent.

  These thermoplastic elastomer components may be used alone or in combination of two or more, for example, an ethylene elastomer and a styrene elastomer are used in combination.

(E) Other components The polypropylene resin composition of the present invention contains, in addition to the components (A) to (D) described above, other components within a range that does not significantly impair the effects of the present invention. It doesn't matter. Other ingredients include calcium carbonate, mica, synthetic mica, wollastonite, montmorillonite and other smectites, whiskers, glass fibers, and other reinforcing fillers, coloring pigments, phenolic, sulfur, List various antioxidants such as phosphorus and lactones, antistatic agents, light stabilizers such as hindered amines, ultraviolet absorbers, dispersants, neutralizers, foaming agents, copper damage inhibitors, lubricants, flame retardants, etc. Can do.

(2) Mixing ratio of components (A) Polypropylene resin, (B) carbon fiber, (C) nucleating agent, and (D) heat used as necessary, constituting the polypropylene resin composition of the present invention The blending ratio of the plastic elastomer is 0.5 to 100 parts by weight, preferably 1 to 50 parts by weight, more preferably 2 to 40 parts by weight, with respect to 100 parts by weight of the component (A). , (C) component is 0.01-5 parts by weight, preferably 0.05-3 parts by weight, more preferably 0.1-1 part by weight. Furthermore, when mix | blending (D) component, it mix | blends so that it may become 1-50 weight part of (D) component with respect to 100 weight part of (A) component.
When the blending ratio of each component deviates from the above range, it is not preferable because the object of the present invention is inferior in the balance between lightness and rigidity, dimensional stability, appearance, fluidity and the like.

(3) Production of polypropylene resin composition The polypropylene resin composition of the present invention can be produced by blending the above-described blending components at the blending ratio described above. Each component is compounded using a conventionally known melt-kneader such as a single screw extruder, twin screw extruder, Banbury mixer, roll kneader, etc. An extruder is most preferably used.
At this time, in order to obtain a resin composition having an excellent balance between lightness and rigidity, which is expensive according to the present invention, it is preferable to devise such that the carbon fiber component does not cause excessive breakage. In the case of melt kneading using, the components other than the carbon fiber are sufficiently melt kneaded in advance, and then the carbon fiber component is fed from a position downstream from the position where the resin component is completely melted by a side feed method or the like. An example of a preferable method is a method of dispersing the converging fibers while minimizing breakage.

Among the polypropylene-based resin compositions obtained as described above, those having a density and flexural modulus satisfying the following relational expression (1) are particularly excellent in the balance between lightness and rigidity, and are dimensionally stable. Because of its excellent properties and appearance, it can be suitably used as a material for various industrial component applications, especially automobile parts, household appliance parts, and residential equipment parts.
FM> 42ρ-36000 (1)
(Where FM represents the flexural modulus (unit: MPa), and ρ represents the density (unit: kg / m ³ ))

2. Molded body of polypropylene resin composition The polypropylene resin composition obtained as described above is molded by a molding method selected from the group consisting of injection molding, compression molding, injection compression molding, and extrusion molding. The molded body has a desired shape. In particular, a molded body having an excellent appearance can be obtained by forming a molded body using a mold that has a textured surface on the surface of the molded body. Among the molded articles of the polypropylene-based resin composition thus obtained, particularly those whose density and flexural modulus satisfy the following relational expression (1) are particularly excellent in the balance between lightness and rigidity, Furthermore, since it is also excellent in dimensional stability and appearance, it is suitably used as various industrial parts, especially as automobile parts, home appliance parts, and housing parts.
FM> 42ρ-36000 (1)
(Where FM represents the flexural modulus (unit: MPa), and ρ represents the density (unit: kg / m ³ ))

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto without departing from the gist thereof.
In addition, the physical-property measuring method used in the Example and the material used are as follows.

1. Physical property measurement method (1) MFR (unit: g / 10 min): Measured according to JIS-K7210 at 230 ° C. and 21.18 N load.
(2) Tensile elongation at break (unit:%): Measured with a No. 1 type test piece at a tensile speed of 10 mm / min in accordance with JIS-K7113.
(3) Density (unit: g / cc, or kg / m ³ ): Measured by an underwater substitution method in accordance with JIS-K7112.
(4) Flexural modulus (unit: MPa): Measured at 23 ° C. according to JIS-K7171.
(5) Izod (IZOD) impact strength (unit: J / m): Measured at 23 ° C. and −30 ° C. according to JIS-K7110.
(6) Deflection temperature under load (unit: ° C.): Measured under the condition of 0.45 MPa in accordance with JIS-K7191-2.
(7) Flow mark generation distance: With an injection molding machine with a clamping pressure of 170 tons, using a mold having a film gate with a width of 2 mm on the short side, a molding sheet of 350 mm × 100 mm × 2 mmt is set at a molding temperature of 220 ° C. Injection molded. The occurrence of the flow mark was visually observed, the distance from the gate to the portion where the flow mark was generated was measured, and judged according to the following criteria.
○: Generation distance exceeds 200 mm. Δ: Generation distance exceeds 100 mm, 200 mm or less. X: Generation distance is 100 mm or less. (8) Mw / Mn: Weight average molecular weight using GPC apparatus (HLC / GPC 150C manufactured by Waters). (Mw) and number average molecular weight (Mn) were measured and calculated as Mw / Mn. Measurement conditions were measured using orthodichlorobenzene as the mobile phase solvent, standard polystyrene as the standard substance, and a set temperature of the column and the sample injection section of 135 ° C.

2. Material (A) Polypropylene resin The polypropylene resin produced in Production Examples 1 to 4 was used. Table 1 shows various indexes of the polypropylene resin used.

(Production Example 1)
(I) Production of Ziegler catalyst Into a reactor having an internal volume of 10 L sufficiently purged with nitrogen, 4000 ml of dehydrated and deoxygenated n-heptane was introduced, and then 8 mol of MgCl ₂ and Ti (On-C ₄ H ₉ ) 16 mol of ₄ was introduced and reacted at 95 ° C. for 2 hours. After completion of the reaction, the temperature was lowered to 40 ° C., and then 960 ml of methylhydropolysiloxane (20 centistokes) was introduced and reacted at 40 ° C. for 3 hours. The produced solid component 1 was washed with n-heptane. Next, 1000 ml of dehydrated and deoxygenated n-heptane was introduced into a reactor having a sufficient internal volume of 10 L, which was purged with nitrogen, and 4.8 mol of the solid component 1 synthesized above was introduced in terms of Mg atoms. Next, 500 ml of n-heptane mixed with 8 mol of SiCl ₄ was introduced into the flask at 30 ° C. over 30 minutes, and reacted for 3 hours while maintaining 70 ° C. After completion of the reaction, the reaction product was washed with n-heptane. Subsequently, 500 ml of n-heptane mixed with 0.48 mol of phthalic acid chloride was introduced into the flask at 70 ° C. over 30 minutes and reacted for 1 hour while maintaining 90 ° C. After completion of the reaction, the reaction product was washed with n-heptane. Next, 200 ml of SiCl ₄ was introduced and reacted at 80 ° C. for 6 hours. After completion of the reaction, the solid component 2 was obtained by thoroughly washing with n-heptane. The titanium content of this product was 1.3% by weight.
Next, 1000 ml of dehydrated and deoxygenated n-heptane was introduced into a sufficiently nitrogen-substituted flask, 100 g of the solid component 2 synthesized above was introduced, and (t-C ₄ H ₉ ) Si (CH ₃ ) ( 24 ml of OCH ₃ ) _{2 and} 34 grams of Al (C ₂ H ₅ ) ₃ were contacted at 30 ° C. for 2 hours. After completion of the contact, the catalyst was thoroughly washed with n-heptane to obtain a solid catalyst component mainly composed of magnesium chloride. The titanium content of this product was 1.1% by weight.
(Ii) Production of polypropylene To a stainless steel autoclave with an internal volume of 200 liters, add 60 liters of n-heptane, 5 g of the above solid catalyst component and 15 g of triethylaluminum, raise the temperature to 75 ° C., supply hydrogen and propylene, A propylene homopolymer (first stage polymerization part) of 750 g / 10 min was produced at 70% by weight of the total weight. After completion of the first stage polymerization, hydrogen was purged. Subsequently, only propylene was supplied in the presence of the first stage polymerization part, and a propylene homopolymer having a weight average molecular weight of 3.5 million was produced as a second stage polymerization part by 30% by weight of the total weight. The overall propylene homopolymer (PP1) obtained by this two-stage polymerization method has an MFR of 42.2 g / 10 min, an isotactic pentad fraction of 98.6%, a die swell ratio of 2.13, Mw / Mn was 10.4.

(Production Example 2)
After producing a polypropylene homopolymer by two-stage polymerization in the same manner as in Production Example 1, propylene, ethylene, and hydrogen were subsequently supplied to carry out copolymerization of propylene and ethylene in the presence of the polypropylene homopolymer. A polypropylene block copolymer (PP2) was obtained. The resulting polypropylene block copolymer had an MFR of 21 g / 10 min, a die swell ratio of 1.5, Mw / Mn of 9.6, and an isotactic pentad fraction of the homopolymer portion of 98.6%, The copolymer portion had a propylene content of 50 wt%, an MFR of 0.42 g / 10 min, and a copolymer portion content of 15 wt%.

(Production Example 3)
A polypropylene homopolymer (PP3) was obtained in the same manner as in Production Example 1, except that the second stage polymerization was not performed, and the supply amount of propylene and hydrogen and the polymerization time were changed. The resulting polypropylene homopolymer had an MFR of 45 g / 10 min, an isotactic pentad fraction of 98.5%, a die swell ratio of 1.2, and an Mw / Mn of 4.

(Production Example 4)
Using the solid catalyst component and the polymerization apparatus produced in Production Example 1, the polypropylene homopolymer was polymerized in one step so that the MFR of the homopolymer portion was 100 g / 10 minutes, and subsequently, propylene and ethylene, And hydrogen were supplied to carry out copolymerization of propylene and ethylene in the presence of a polypropylene homopolymer to obtain a polypropylene block copolymer (PP4). The obtained polypropylene block copolymer had an MFR of 60 g / 10 min, a die swell ratio of 1.3, Mw / Mn of 5, and an isotactic pentad fraction of the homopolymer portion of 98.6%. The propylene content of the coalescence part was 57% by weight, the MFR was 0.17 g / 10 min, and the content of the copolymer part was 8% by weight.

(B) Carbon fiber The following commercially available chopped carbon fibers (CF1 to CF2) were used.
CF1: Fiber diameter 7 μm, fiber length 6 mm (PAN-based carbon fiber, Toray TS12 (trade name))
CF2: fiber diameter 10 μm, fiber length 6 mm (pitch-based carbon fiber, K223SE (trade name) manufactured by Mitsubishi Chemical)

(C) Nucleating agent The following nucleating agents were used.
KA1: aromatic carboxylic acid metal salt (ALPTBBA (trade name) manufactured by Shell Chemical)
KA2: Organophosphate metal salt (NA11 (trade name) manufactured by Asahi Denka Kogyo)
KA3: Talc (Matsumura Sangyo High Filler # 7 (trade name))
KA4: Sorbitol (New Nippon Rika's Gel All MD (trade name))

(D) Thermoplastic elastomer The following commercially available elastomers (EL1 to EL3) were used.
EL1: Ethylene octene copolymer having a density of 0.864 g / cm ³ , MFR of 1.4 g / 10 min and an ethylene content of 75% by weight (EG8180 (trade name) manufactured by DuPont Dow Elastomer)
EL2: ethylene / butene copolymer having a density of 0.862 g / cm ³ , an MFR of 1.0 g / 10 min, and an ethylene content of 69% by weight (A0550S (trade name) manufactured by Mitsui Chemicals)
EL3: SEBS having a density of 0.900 g / cm ³ , MFR of 9.0 g / 10 min, and a styrene content of 13% by weight (G1657 manufactured by Shell (trade name))

(Examples 1 to 13)
Ingredients other than carbon fiber are blended according to the composition shown in Table 2, 0.1 parts by weight of a phenolic antioxidant (Ciba Specialty Chemicals: Irganox 1010), phosphorus antioxidant (Ciba Specialty Chemicals) : Irgafos 168) After mixing with 0.05 parts by weight and 0.3 parts by weight of zinc stearate, the mixture is fed from the root hopper of the same-direction rotating twin-screw extruder (manufactured by Nippon Steel Co., Ltd .: TEX30α). 3 side feed using a side feeder installed on the base side of 3 barrels so that the carbon fiber component has a predetermined concentration, melt kneaded at a screw speed of 300 rpm and an extrusion rate of 15 kg / h, and a pellet-shaped polypropylene resin composition I got a thing. The obtained pellets were injection molded under conditions of a mold temperature of 40 ° C. and a cylinder temperature of 220 ° C. to obtain various test pieces of the propylene resin composition. Various physical properties were evaluated by the above-described methods using the obtained test pieces. The evaluation results are shown in Table 3.

(Comparative Examples 1-15)
With the blending composition shown in Table 4, a propylene-based resin composition was obtained in the same manner as in the examples, and various physical properties were evaluated. The evaluation results are shown in Table 5. The balance of lightness, rigidity, and heat resistance caused by the structure of various blending components and the combination thereof, and the appearance defect at the time of injection molding were confirmed.

As is clear from Table 5, Comparative Examples 1 to 6 in which no nucleating agent was used had lower bending elastic modulus and load deflection temperature than the corresponding Examples 1 to 6, and the rigidity was insufficient.
In Comparative Examples 7 to 11, the structure of polypropylene does not satisfy the provisions of the present invention, so that not only the flow mark is inferior, but also the use of the specific nucleating agent defined in the present invention does not sufficiently improve the rigidity. Thus, the balance between the flexural modulus, the deflection temperature under load and the light weight was inferior.
In Comparative Examples 12 to 13 that do not use carbon fiber, the flexural modulus and the deflection temperature under load were lower than those of the corresponding Examples 3 to 6, and the rigidity was insufficient.
In Comparative Examples 14 to 15 having different types of nucleating agents, the flexural modulus and load deflection temperature were lower than those of the corresponding Examples 2 and 4, and the rigidity was insufficient.

  The polypropylene-based resin composition of the present invention, which is composed of polypropylene, carbon fiber, and a nucleating agent having a specific structure, and further, if necessary, an elastomer-blended component, and a molded product thereof are lightweight. It is a useful material in various industrial parts fields, especially in applications such as automobile parts, home appliance parts, and housing parts because of its excellent balance of rigidity, heat resistance, molded appearance, and heat source recyclability. The excellent balance between lightness and rigidity, especially when used as an automobile part, reduces the weight of the vehicle, which improves fuel efficiency and, in turn, saves finite energy resources and protects the global environment. Will also contribute. Moreover, since the polypropylene resin composition of the present invention and the molded product thereof have high rigidity and heat resistance, it is virtually unnecessary to add an inorganic filler, and as a result, ash is generated during incineration. It is a material that can be effectively used as a heat source. This contributes to the conversion of the composite resin that had previously been landfilled into a heat source in the form of incineration, and also contributes to a significant reduction in the amount of landfill waste that has become a significant burden on the global environment. Therefore, its industrial value is extremely large.

Claims (9)

(B) 0.5 to 100 parts by weight of carbon fiber, and (C) 0.01 to 5 parts by weight of a nucleating agent with respect to 100 parts by weight of the following (A) polypropylene resin. Composition.
(A) Polypropylene resin: The die swell ratio is 1.5 to 2.5, and the ratio (Mw / Mn) of the weight average molecular weight Mw and the number average molecular weight Mn measured by gel permeation chromatography (GPC) is 7 to 7 13. Propylene homopolymer (a) having an isotactic pentad fraction of 96% or more and a melt flow rate (measured at 230 ° C. according to JIS K7210, hereinafter referred to as MFR) of 20 to 100 g / 10 min. Or the propylene content obtained by copolymerizing the propylene homopolymer (a), propylene and an α-olefin having 2 to 12 carbon atoms (excluding 3), and the MFR is 0.001 to 6 g. Propylene block copolymer having a MFR of 5 to 80 g / 10 min (b) Polypropylene resin selected from (B) Carbon fiber: Carbon fiber having a fiber diameter of more than 2 μm and not more than 15 μm and a fiber length of 1-20 mm (C) Nucleating agent: Aromatic carboxylate metal salt, organophosphate metal Nucleating agent selected from the group consisting of salts and metal salts of rosin acid   The polypropylene resin composition according to claim 1, wherein the propylene homopolymer (a) is a polypropylene homopolymer produced by multistage polymerization.   The polypropylene resin composition according to claim 2, wherein the propylene homopolymer (a) contains 50 to 95% by weight of a propylene polymer having an MFR of 200 to 1000 g / 10 min.   The polypropylene resin composition according to any one of claims 1 to 3, wherein the metal salt as a nucleating agent is a metal salt of aluminum or sodium. (A) At least one selected from ethylene elastomer or styrene elastomer having an MFR of 0.1 to 15 g / 10 min and a density of 0.850 to 0.910 g / cm ³ with respect to 100 parts by weight of the polypropylene resin. The polypropylene-based resin composition according to any one of claims 1 to 4, wherein the thermoplastic elastomer (D) is contained in an amount of 1 to 50 parts by weight. The polypropylene resin composition according to any one of claims 1 to 5, wherein the relationship between density and flexural modulus satisfies the following relational expression (1).
FM> 42ρ-36000 (1)
(Where FM represents the flexural modulus (unit: MPa), and ρ represents the density (unit: kg / m ³ ))   The molded object formed by shape | molding the polypropylene resin composition of any one of Claims 1-6 by the shaping | molding processing method chosen from the group which consists of injection molding, compression molding, extrusion molding, and injection compression molding. The molded product according to claim 7, wherein the relationship between the density and the flexural modulus satisfies the following relational expression (1).
FM> 42ρ-36000 (1)
(Where FM represents the flexural modulus (unit: MPa), and ρ represents the density (unit: kg / m ³ ))   A vehicle part, a housing part, or a home appliance part comprising the molded article according to claim 7 or 8.