TW201345931A - Polypropylene resin composition for sheet molding - Google Patents

Abstract

To efficiently provide a sheet-like molded article which has excellent transparency, high rigidity and sufficient impact resistance, while being stable with respect to shape. A polypropylene resin composition for sheets, which contains: 99.95-99.5% by weight of a polypropylene copolymer that is obtained by copolymerizing propylene and ethylene using a catalyst that contains (A) a solid catalyst which contains, as an essential component, an electron-donating compound that is selected from among magnesium, titanium, halogens and succinates; (B) an organic aluminum compound; and (C) an external electron-donating compound which is selected from among silicon compounds; and 0.05-0.5% by weight of a crystal nucleator. The polypropylene resin composition for sheets is characterized in that: the polypropylene copolymer has a polydispersity of 4.5-10; the polypropylene copolymer has an ethylene content of 0.3-2.0% by weight based on the weight of the polypropylene copolymer; and the composition has a melt flow rate at 230 DEG C of 1-8 g/10 minutes.

Description

Polypropylene resin composition for sheet forming

The present invention relates to a polypropylene resin composition for sheet forming. More specifically, the polypropylene resin composition is excellent in processability and transparent, and can be processed into a sheet having high rigidity and sufficient impact strength.

Polypropylene which is inexpensive, excellent in rigidity, moisture resistance, and heat resistance is widely used in various industrial fields. In particular, the polypropylene resin composition is excellent in appearance, mechanical properties, packaging suitability, and the like, and is used for the production of a molded article, particularly a sheet-like molded article in packaging applications such as food packaging or fiber packaging. In packaging applications, the transparency of the contents can be confirmed by special requirements.

As a method of improving the transparency of the polypropylene resin composition, a method of adding a crystal nucleating agent to a polypropylene resin is known. A crystalline polymer composition comprising a crystalline polymer composition which exhibits a sufficient effect of adding transparency to transparency is disclosed in Patent Document 1 (JP-A-2005-120237), and a crystalline polymer composition is disclosed. It is composed of a lithium salt of a cyclic phosphate ester having a specific structure of a polyolefin-based polymer, a fatty organic acid metal salt, and a specific compound having a structure of an organic acid decylamine. also In JP-A-2009-299039, a polypropylene resin composition for a thermoformed sheet containing a polypropylene resin and a compound having a specific sorbitol-based structure is disclosed.

Although the transparency of the resin is mentioned in the above-mentioned patent documents, the sheet formability, the secondary workability, the passability of the molded article after heating (secondary processing), and the like are not mentioned.

Patent Document 1: Japanese Patent Laid-Open No. 2005-120237

Patent Document 2: JP-A-2009-299039

Patent Document 3: International Publication No. 2009/069483

Patent Document 4: International Publication No. 2009/057747

Patent Document 5: Japanese Patent Laid-Open No. 2005-306910

Patent Document 6: Japanese Patent Laid-Open No. 2004-131537

Patent Document 7: Japanese Special Table 2002-542347

The present invention provides a polypropylene-based resin composition containing polypropylene, which is a solid catalyst component containing Mg, Ti, and a halogen, and an aluminum alkyl containing a succinate-based electron donor compound. The polypropylene resin composition has a specific melt flow rate value and ethylene content, excellent sheet formability, and secondary workability, which are obtained by polymerization in the presence of a catalyst and a catalyst system containing a ruthenium compound. It is also possible to provide a polypropylene-based resin composition which is preferably thinned in packaging applications by properly adding a specific crystal nucleating agent by using polypropylene produced by using a specific catalyst. Production of sheet-shaped molded articles.

The aspect of the invention is as follows:

A polypropylene resin composition for a sheet comprising 99.95 to 99.5% by weight of a polypropylene copolymer; and a polypropylene resin composition for a sheet having 0.05 to 0.5% by weight of a crystal nucleating agent, which has the following characteristics: The polypropylene copolymer has a polydispersity index of 4.5 to 10, and the ethylene content of the polypropylene copolymer is 0.3 to 2.0% by weight based on the weight of the polypropylene copolymer, and the melt flow rate at 230 ° C of the composition. The polypropylene copolymer is a solid catalyst containing (A) an electron donor compound selected from magnesium, titanium, a halogen, and a succinic acid ester as an essential component, and (B) an organoaluminum compound, for 1 to 8 g/10 minutes. And (C) a catalyst selected from the group consisting of an external electron donor compound of a ruthenium compound, which is obtained by copolymerizing propylene with ethylene.

2. The resin composition according to the above 1, wherein the crystal nucleating agent is selected from the group consisting of a nonol nucleating agent, a sorbitol nucleating agent, a phosphate ester nucleating agent, and a triamino benzene derivative nucleating agent. a carboxylic acid metal salt nucleating agent and a xylitol nucleating agent.

A sheet produced from the polypropylene resin composition described in the above 1 or 2.

Hereinafter, the present invention will be described in detail.

First, the polypropylene resin composition of the present invention will be described. The present invention relates to a polypropylene resin composition for a sheet comprising 99.95 to 99.5% by weight of a polypropylene copolymer, and a polypropylene resin composition for a sheet having 0.05 to 0.5% by weight of a crystal nucleating agent, which has the following Characteristics: Polypropylene copolymer has a polydispersity index of 4.5 to 10, and the ethylene content of the polypropylene copolymer is 0.3 to 2.0% by weight based on the weight of the polypropylene copolymer, and the composition is melted at 230 ° C. The flow rate is 1 to 8 g/10 min. The polypropylene copolymer is a solid catalyst containing (A) an electron donor compound selected from the group consisting of magnesium, titanium, halogen, and succinic acid as an essential component, and (B) organic The aluminum compound and (C) a catalyst selected from the group consisting of an external electron donor compound of a ruthenium compound, and a copolymer of propylene and ethylene.

The polypropylene of the first component of the present invention is a solid catalyst containing (A) an electron donor compound selected from the group consisting of magnesium, titanium, halogen, and succinic acid as an essential component, (B) an organoaluminum compound, and ( C) Manufacturer of a catalyst selected from an external electron donor compound of a ruthenium compound.

The solid catalyst of the component (A) used for the production of the first component of the present invention contains, as an essential component, a compound selected from the group consisting of magnesium, titanium, halogen, and an electron donor. Regarding the solid catalyst component, there are a number of previously described documents which disclose the method of manufacture thereof. Specifically, the solid catalyst component is made to be magnesia The compound is obtained by contacting the titanium compound and the electron donor compound with each other. For example, by (1) a complex of a magnesium compound or a magnesium compound and an electron donor compound, pulverized or not pulverized in the presence or absence of an electron donor compound, a pulverization aid, or the like, such as an electron a method in which a supply compound and/or an organoaluminum compound or a halogen-containing ruthenium compound or the like is subjected to a preliminary treatment, or a solid obtained without preliminary treatment is reacted with a titanium compound which is liquid phase under the reaction conditions; (2) a method of precipitating a solid titanium compound by reacting a liquid substance of a magnesium compound with a liquid titanium compound in the presence or absence of an electron donor compound; (3) a solid magnesium compound and a method for reacting a liquid titanium compound and an electron donor compound; (4) a method for reacting a titanium compound with the above (2) or (3); (5) for the above (1) or (2) or (3) a method of reacting an electron donor compound and a titanium compound, and (6) a complex of a magnesium compound or a magnesium compound and an electron donor compound in an electron donor compound, a pulverization aid, or the like Under or not present The mixture is pulverized in the presence of a titanium compound and a reaction aid such as an electron donor compound and/or an organoaluminum compound or a halogen-containing ruthenium compound, or a solid is obtained without a preliminary treatment, and the solid is obtained. a method of treating with a halogen or a halogen compound or an aromatic hydrocarbon; and (7) a method of treating the compound obtained by the above (1) to (5) with a halogen or a halogen compound or an aromatic hydrocarbon, and the like. The solid catalyst component of the component (A) used in the present invention.

The titanium compound used for the preparation of the solid catalyst component (A) used in the production of the first component of the present invention is preferably a formula: Ti(OR) _g X _4-g (R is a hydrocarbon group, and X is a halogen. The tetravalent titanium compound represented by 0≦g≦4) is preferred. More specifically, as for _{example, TiCl 4, TiBr 4, TiI} 4 , etc. titanium _{tetrahalide; Ti (OCH 3) Cl 3} , Ti (OC 2 H 5) Cl 3, Ti (O n -C 4 H 9 a trihalogenated alkoxytitanium such as Cl ₃ , Ti(OC ₂ H ₅ )Br ₃ , Ti(O _iso C ₄ H ₉ )Br ₃ or the like; Ti(OCH ₃ ) ₂ Cl ₂ , Ti(OC ₂ H ₅ ) ₂ Dihalogenated alkoxytitanium such as Cl ₂ , Ti(O _n -C ₄ H ₉ ) ₂ Cl ₂ , Ti(OC ₂ H ₅ ) ₂ Br ₂ or the like; Ti(OCH ₃ ) ₃ Cl, Ti(OC ₂ H ₅ ) ₃ Cl, Ti(O _n -C ₄ H ₉ ) ₃ Cl, Ti(OC ₂ H ₅ ) ₃ Br, etc. monohalogenated alkoxytitanium; Ti(OCH ₃ ) ₄ , Ti(OC ₂ H ₅ ) ₄ , Ti A titanium tetraalkoxide such as (O _n -C ₄ H ₉ ) ₄ or the like is preferable, and among them, a halogen-containing titanium compound, particularly a titanium tetrahalide, particularly preferably titanium tetrachloride.

The magnesium compound used for the preparation of the solid catalyst component (A) used in the production of the first component of the present invention has magnesium. Carbon bond or magnesium. Examples of the hydrogen-bonded magnesium compound include dimethylmagnesium, diethylmagnesium, dipropylmagnesium, dibutylmagnesium, dipentaluminate, dihexylmagnesium, di-n-magnesium, ethylmagnesium chloride, propylmagnesium chloride, and butylmagnesium chloride. Hexyl magnesium chloride, pentyl magnesium chloride, butyl ethoxy magnesium, ethyl butyl magnesium, butyl magnesium hydride, and the like. These magnesium compounds can be used, for example, in the form of a complex with organoaluminum, or in a liquid state or in a solid state. Further preferably, the magnesium compound may, for example, be a magnesium halide such as magnesium chloride, magnesium bromide, magnesium iodide or magnesium fluoride; methoxy magnesium chloride, ethoxy magnesium chloride, isopropoxy magnesium chloride, butoxy magnesium chloride or xin An alkoxy magnesium halide such as oxymagnesium chloride; an aryloxy magnesium halide such as phenoxymagnesium chloride or methylphenoxymagnesium chloride; ethoxy magnesium, magnesium isopropoxide, magnesium butoxide, n-octyl oxide Alkoxymagnesium such as magnesium or 2-ethylhexyloxymagnesium; aryloxymagnesium such as phenoxymagnesium or dimethylphenoxymagnesium; magnesium carboxylic acid such as magnesium laurate or magnesium stearate Salt and so on.

The electron donor compound used for the preparation of the solid catalyst component (A) used in the production of the first component of the present invention is generally referred to as an "internal electron donor". The electron donor compound is known to contain an oxygen-containing electron supplier such as an alcohol, a phenol, a ketone, an aldehyde, a carboxylic acid, an organic acid or an inorganic acid ester, an ether, an acid amide or an acid anhydride, ammonia, an amine, a nitrile, or the like. A nitrogen-containing electron donor or the like of an isocyanate or the like, and the present invention uses a succinate-based electron donor compound.

A preferred succinate compound having the formula I: (wherein, the radicals R ₁ and R ₂ are the same or different, and optionally have a C ₁ -C ₂₀ linear or branched alkyl, alkenyl, cycloalkyl, aryl, arylalkane containing a hetero atom. a group, or an alkylaryl group; the group R ₃ to R ₆ , which are the same or different, or optionally a hetero atom, a C ₁ -C ₂₀ linear or branched alkyl group, an alkenyl group, a cycloalkyl group, or an aromatic group a succinate (succinate) structure in which a group, an arylalkyl group, or an alkylaryl group, bonded to the same carbon atom or a group of different carbon atoms, R ₃ to R ₆ , may be bonded together to form a ring. Selected among the compounds.

R ₁ and R _{2 are} preferably a C ₁ to C ₈ alkyl group, a cycloalkyl group, an aryl group, an arylalkyl group, and an alkylaryl group. R ₁ and R _{2 are} particularly preferably compounds selected from the group consisting of a monoalkyl group, particularly a branched alkyl group. Preferred examples of the R ₁ and R ₂ groups are methyl, ethyl, n-propyl, n-butyl, isobutyl, neopentyl, 2-ethylhexyl. Particularly preferred are ethyl, isopropyl, and neopentyl.

One of the preferred groups of compounds represented by the formula (I), wherein R ₃ to R ₅ are a hydrogen atom, and R ₆ is a branched alkyl group having 3 to 10 carbon atoms, a cycloalkyl group, an aryl group or an aryl group. Alkyl, and alkylaryl. Specific examples of preferred monosubstituted succinate compounds are diethyl-secondary butyl succinate, diethyl-trienyl succinate, diethylcyclopropyl succinate, and Ethyl norbornyl succinate, diethyl perhydro succinate, diethyl trimethyl decyl succinate, diethyl methoxy succinate, diethyl-p-methoxy benzene Succinate, diethyl-p-chlorophenyl succinate, diethyl phenyl succinate, diethyl cyclohexyl succinate, diethyl benzyl succinate, diethyl cyclohexyl Succinate, diethyl-tertiary butyl succinate, diethyl isobutyl succinate, diethyl isopropyl succinate, diethyl neopentyl succinate, diethyl Isoamyl succinate, diethyl (1-trifluoromethylethyl) succinate, diethyl decyl succinate, 1-(ethoxy carbodiisobutyl phenyl) succinate , diisobutyl-secondary butyl succinate, diisobutyl tertiary hexyl succinate, diisobutylcyclopropyl succinate, diisobutylnorbornyl succinate, diisobutyl Hydrogenyl Persylate, diisobutyltrimethyldecyl succinate, diisobutylmethoxysuccinate, diisobutyl-p-methoxyphenyl succinate, diisobutyl-p-chlorophenyl Succinate, diisobutylcyclohexyl succinate, diisobutylbenzyl succinate, diisobutylcyclohexylmethyl succinate, diisobutyl-tertiary butyl succinate, Isobutyl isobutyl succinate, diisobutyl isopropyl succinate, diisobutyl neopentyl succinate, diisobutyl isoamyl succinate, diisobutyl (1- Trifluoromethylethyl succinate, diisobutyl decyl succinate, di-n-pentyl-secondary butyl succinate, di-n-pentyl tertiary hexyl succinate, di-n-pentyl ring Propyl succinate, di-n-pentylnorbornyl succinate, di-new amyl perhydrosuccinate, di-n-pentyltrimethyldecyl succinate, di-n-pentylmethoxysuccinic acid Ester, di-n-pentyl-p-methoxyphenyl succinate, di-n-pentyl-p-chlorophenyl succinate, di-p-pentylphenyl succinate, di-n-pentylcyclohexyl succinate, Dipentylbenzyl Succinate, di-n-pentylcyclohexylmethyl succinate, di-n-pentyl-tert-butyl succinate, di-n-pentyl isobutyl succinate, di-n-pentyl isopropyl succinate , di-new amyl neopentyl succinate, di-new amyl isoamyl succinate, di-n-pentyl (1-trifluoromethylethyl) succinate, di-n-pentyl decyl succinate .

Other preferred groups of compounds within the scope of formula (I), wherein at least two of R ₃ to R ₆ are different from hydrogen, optionally containing a hetero atom selected from a line or branch of C ₁ to C ₂₀ An alkyl, alkenyl, cycloalkyl, aryl, arylalkyl, or alkylaryl group. Particularly preferred are compounds which are different from the two groups of hydrogen bonded to the same carbon atom. Further, a compound different from at least two groups of hydrogen, that is, R ₃ and R ₅ , or a compound in which R ₄ and R _{6 are} bonded to different carbon atoms is particularly preferable. Specific examples of preferred disubstituted succinates are diethyl-2,2-dimethylsuccinate, diethyl-2-ethyl-2-methylsuccinate, diethyl-2- Benzyl-2-isopropylsuccinate, diethyl-2-cyclohexylmethyl-2-isobutyl succinate, diethyl-2-cyclopentyl-2-n-butyl succinate , diethyl-2,2-diisobutyl succinate, diethyl-2-cyclohexyl-2-ethyl succinate, diethyl-2-isopropyl-2-methyl succinic acid Ester, diethyl-2-tetradecyl-2-ethyl succinate, diethyl-2-isobutyl-2-ethyl succinate, diethyl-2-(1-trifluoromethyl) Ethyl ethyl)-2-methyl succinate, diethyl-2-isopentyl-2-isobutyl succinate, diethyl-2-phenyl-2-n-butyl succinate, Diisobutyl-2,2-dimethylsuccinate, diisobutyl-2-ethyl-2-methylsuccinate, diisobutyl-2-benzyl-2-isopropylamber Acid ester, diisobutyl-2-cyclohexylmethyl-2-isobutyl succinate, diisobutyl-2-cyclopentyl-2-n-butyl succinate, diisobutyl-2 ,2-diisobutyl succinate, diisobutyl-2-cyclohexyl-2-ethyl succinate, diisobutyl-2-iso 2-methyl succinate, diisobutyl-2-tetradecyl-2-ethyl succinate, diisobutyl-2-isobutyl-2-ethyl succinate, diiso Butyl-2-(1-trifluoromethylethyl)-2-methylsuccinate, diisobutyl-2-isopentyl-2-isobutyl succinate, diisobutyl-2 -Phenyl-2-n-butyl succinate, di-n-pentyl-2,2-dimethyl succinate, di-n-pentyl-2-ethyl-2-methyl succinate, dioxane Benzyl-2-benzyl-2-isopropylsuccinate, di-n-pentyl-2-cyclohexylmethyl-2-isobutyl succinate, di-n-pentyl-2-cyclopentyl-2- n-Butyl succinate, di-n-pentyl-2,2-diisobutyl succinate, di-n-pentyl-2-cyclohexyl-2-ethyl succinate, di-n-pentyl-2-iso Propyl-2-methyl succinate, di-n-pentyl-2-tetradecyl-2-ethyl succinate, di-n-pentyl-2-isobutyl-2-ethyl succinate, two Neopentyl-2-(1-trifluoromethylethyl)-2-methylsuccinate, di-n-pentyl-2-isopentyl-2-isobutyl succinate, di-n-pentyl- 2-Phenyl-2-n-butyl succinate.

Further, a compound different from at least two groups of hydrogen, that is, R ₃ and R ₅ , or a compound in which R ₄ and R _{6 are} bonded to different carbon atoms is particularly preferable. Specific examples of preferred compounds are diethyl-2,3-bis(trimethyldecyl)succinate, diethyl-2,2-secondary butyl-3-methylsuccinate, and Ethyl-2-(3,3,3-trifluoropropyl)-3-methylsuccinate, diethyl-2,3-bis(2-ethylbutyl)succinate, diethyl -2,3-diethyl-2-isopropyl succinate, diethyl-2,3-diisopropyl-2-methyl succinate, diethyl-2,3-dicyclohexyl -2-methyl succinate, diethyl-2,3-dicyclohexyl-2-methyldiethyl-2,3-dibenzyl succinate, diethyl-2,3-diiso Propyl succinate, diethyl-2,3-bis(cyclohexylmethyl) succinate, diethyl-2,3-di-tert-butyl succinate, diethyl-2,3 -diisobutyl succinate, diethyl-2,3-diopentyl succinate, diethyl-2,3-diisoamyl succinate, diethyl-2,3-( 1-trifluoromethylethyl)succinate, diethyl-2,3-tetradecyl succinate, diethyl-2,3-mercaptosuccinate, diethyl-2-isopropyl 3-isobutyl succinate, diethyl-2-tributyl-3-isopropyl succinate, diethyl-2-isopropyl-3-cyclohexyl succinate, two B 2-isopentyl-3-cyclohexyl succinate, diethyl-2-tetradecyl-3-cyclohexyl succinate, diethyl-2-cyclohexyl-3-cyclopentyl succinic acid Ester, diisobutyl-2,3-diethyl-2-isopropylsuccinate, diisobutyl-2,3-diisopropyl-2-methylsuccinate, diisobutyl -2,3-dicyclohexyl-2-methyl succinate, diisobutyl-2,3-dibenzyl succinate, diisobutyl-2,3-diisopropyl succinate, Diisobutyl-2,3-bis(cyclohexylmethyl)succinate, diisobutyl-2,3-di-tertiary butyl succinate, diisobutyl-2,3-diiso Butyl succinate, diisobutyl-2,3-diopentyl succinate, diisobutyl-2,3-diisoamyl succinate, diisobutyl-2,3-( 1-trifluoromethylethyl)succinate, diisobutyl-2,3-tetradecyl succinate, diisobutyl-2,3-decyl succinate, diisobutyl-2 -isopropyl-3-isobutyl succinate, diisobutyl-2-tributyl-3-isopropyl succinate, diisobutyl-2-isopropyl-3-cyclohexyl Succinate, diisobutyl-2-isopentyl-3-cyclohexyl succinate, diisobutyl-2-tetradecyl-3-cyclohexyl succinic acid Ester, diisobutyl-2-cyclohexyl-3-cyclopentyl succinate, di-n-pentyl-2,3-bis(trimethyldecyl) succinate, di-n-pentyl-2,2 -Secondary butyl-3-methyl succinate, di-n-pentyl-2-(3,3,3-trifluoropropyl)-3-methyl succinate, di-n-pentyl-2,3 - bis(2-ethylbutyl) succinate, di-n-pentyl-2,3-diethyl-2-isopropyl succinate, di-n-pentyl-2,3-diisopropyl- 2-methylsuccinate, di-n-pentyl-2,3-dicyclohexyl-2-methyl succinate, di-n-pentyl-2,3-dibenzyl succinate, di-n-pentyl- 2,3-diisopropylsuccinate, di-n-pentyl-2,3-bis(cyclohexylmethyl)succinate, di-n-pentyl-2,3-di-tert-butyl succinate , di-new amyl-2,3-diisobutyl succinate, di-n-pentyl-2,3-di-p-pentyl succinate, di-n-pentyl-2,3-diisoamyl succinic acid Ester, di-n-pentyl-2,3-(1-trifluoromethylethyl) succinate, di-n-pentyl-2,3-tetradecyl succinate, di-n-pentyl-2,3- Mercapto succinate, di-n-pentyl-2-isopropyl-3-isobutyl succinate, di-n-pentyl-2-tributyl-3-isopropyl succinate, dipentane 2-isopropyl-3-cyclohexyl succinate, di-n-pentyl-2-isopentyl-3-cyclohexyl succinate, di-n-pentyl-2-tetradecyl-3-cyclohexyl Succinate, di-n-pentyl-2-cyclohexyl-3-cyclopentyl succinate.

Among the compounds of the formula I, it is preferred to use a combination of several of the groups R ₃ to R ₆ to form a cyclic compound. Such a compound may, for example, be a compound of Patent Document 7, for example, 1-(ethoxycarbonyl)-1-(ethoxyethyl)-2,6-dimethylcyclohexane, 1- (ethoxycarbonyl)-1-(ethoxyethenyl)-2,5-dimethylcyclopentane, 1-(ethoxycarbonyl)-1-(ethoxyethenylmethyl) 2-methylcyclohexane, 1-(ethoxycarbonyl)-1-(ethoxy(cyclohexyl)ethenyl)cyclohexane. Further, for example, a cyclic succinate compound disclosed in Patent Document 3 can also be applied.

As an example of the other cyclic succinate compound, a compound disclosed in Patent Document 4 is preferably used.

Among the compounds of the formula I, when the radicals R ₃ to R ₆ contain a hetero atom, it is preferred that the hetero atom is a Group 15 atom comprising a nitrogen and a phosphorus atom, or a Group 16 atom comprising an oxygen and a sulfur atom. The compound having a group R ₃ to R _{6 which} is a Group 15 atom can be, for example, a compound disclosed in Patent Document 5. On the other hand, a compound containing a group R ₃ to R ₆ as a group 16 atom may, for example, be a compound disclosed in Patent Document 6.

The halogen atom constituting the solid catalyst component used in the production of the first component of the present invention may, for example, be fluorine, chlorine, bromine or iodine or a mixture thereof, and particularly preferably chlorine.

The organoaluminum compound of the component (B) used for the production of the first component of the present invention may be, for example, a trialkylaluminum such as trialkylaluminum such as triethylaluminum or tributylaluminum or aluminum triisobutylene. And alkoxylated alkyl aluminum such as diethylaluminum ethoxide or dibutylaluminum butyl oxide, ethylaluminum sesquioxide, dibutylaluminum sesquioxide, etc. Halogenated two of alkoxylated aluminum alkyl, diethylaluminum chloride, dibutylaluminum chloride, diethylaluminum bromide, etc., having an average composition represented by R ¹ _2.5 Al(OR ² ) _0.5 or the like Aluminium alkyl, ethylaluminum sesquichloride, butylaluminum sesquichloride, ethylaluminum sesquichloride, etc., sesquihalogenated aluminum alkyl, ethylaluminum dichloride, propyl aluminum dichloride a partially semi-halogenated alkyl aluminum such as a dihalogenated aluminum alkyl such as butyl aluminum bromide or the like, a dialkyl aluminum hydride such as dibutyl aluminum hydride or a diethyl aluminum dihydrogenate. a partially hydrogenated alkyl aluminum such as an alkyl aluminum dihydride such as dihydropropyl aluminum, ethyl aluminum ethoxychloride, butyl aluminum butyl hydride or ethyl aluminum ethoxy bromide. Local alkoxy And halogenated aluminum alkyl and the like.

The electron donor compound of the component (C) used for the production of the first component of the present invention is generally referred to as an "external electron donor". As such an electron donor compound, an organic ruthenium compound is preferably used. Preferred organic hydrazine compounds include, for example, trimethylmethoxy decane, trimethyl ethoxy decane, dimethyl dimethoxy decane, dimethyl diethoxy decane, diisopropyl dimethoxy decane, and tertiary Butyl methyl dimethoxy decane, tertiary butyl methyl diethoxy decane, tertiary pentyl methyl diethoxy decane, diphenyl dimethoxy decane, phenyl methyl dimethoxy decane, diphenyl diethoxy Decane, bis-o-tolyl dimethoxy decane, bis-m-tolyl dimethoxy decane, bis-p-tolyl dimethoxy decane, bis-p-tolyl diethoxy decane, bisethyl phenyl dimethoxy decane, bicyclo Amyl dimethoxy decane, dicyclohexyl dimethoxy decane, cyclohexyl methyl dimethoxy decane, cyclohexyl methyl diethoxy decane, ethyl trimethoxy decane, ethyl triethoxy decane, vinyl trimethoxy Decane, methyltrimethoxy decane, n-propyltriethoxy decane, decyltrimethoxy decane, decyltriethoxy decane, phenyltrimethoxy decane, γ-chloropropyltrimethoxy decane, methyltriethoxy Decane, ethyl triethoxy decane, ethylene triethoxy decane, tertiary butyl triethoxy decane, tertiary Silane triethoxysilane, n-butyl triethoxysilane Silane, Silane isobutyl triethoxysilane, phenyl triethoxysilane Silane, [gamma] aminopropyl triethoxysilane Silane, chloro Triethoxyoxane, ethyltriisopropoxide, vinyl tributoxy decane, cyclohexyltrimethoxy decane, cyclohexyltriethoxy decane, 2-norbornane trimethoxy decane, 2-norbornane triethyl Oxy decane, 2-norbornane methyl dimethoxy decane, ethyl decanoate, butyl phthalate, trimethyl phenoxy decane, methyl tri propylene oxy decane, vinyl tris (β-methoxy B Oxy decane), vinyl triethoxy decane, dimethyl tetraethoxy dioxane, etc., especially ethyl triethoxy decane, n-propyl triethoxy decane, n-butyl triethoxy decane , tertiary hexyl triethoxy decane, vinyl triethoxy decane, phenyl triethoxy decane, vinyl tributoxy decane, diphenyl dimethoxy decane, diisopropyl dimethoxy decane, dicyclopentane Dimethoxyoxane, cyclohexylmethyldimethoxydecane, phenylmethyldimethoxydecane, bis-p-methoxydimethoxydecane, p-tolylmethyldimethoxydecane, dicyclohexyldimethoxy Decane, cyclohexylmethyldimethoxydecane, 2-norbornane triethoxyoxane, 2-norbornanemethyldimethoxydecane, diphenyldiethoxydecane Preferably silicon and ethyl.

The polypropylene of the first component of the present invention has a molecular weight distribution having a polydispersity index (PI) of 4.5 to 10, preferably 5.0 to 8.0. When the PI is less than 4.5, the drooping time is short and it is easy to fall. If the PI exceeds 10, the transparency deteriorates.

The crystal nucleating agent of the second component of the present invention is preferably selected from the group consisting of a nonyl alcohol nucleating agent, a sorbitol nucleating agent, a phosphate ester nucleating agent, a triamino benzene derivative nucleating agent, and a carboxylic acid metal salt nucleus. And xylitol nucleating agent. A crystal nucleating agent having a nonol structure, such as 1,2,3-trihydroxy-4,6:5,7-bis-[(4-propylphenyl)methylene]-nolol a nucleating agent having a xylitol structure, such as bis-1,3:2,4-(5',6',7',8'-tetrahydro-2-naphthalenecarbaldehydebenzylidene) 1 -allyl Xylitol, bis-1,3:2,4-(3',4'-dimethylbenzylidene)1-propyl xylitol, a nucleating agent having a sorbitol structure, for example Bis-1,3:2,4-(4'-ethylbenzylidene)1-allyl sorbitol, bis-1,3:2,4-(3'-methyl-4'-fluoro -benzylidene) 1-propyl sorbitol, bis-1,3:2,4-(3',4'-dimethylbenzylidene)1'-methyl-2'-propenyl sorbose Alcohol, bis-1,3,2,4-dibenzylidene 2',3'-dibromopropyl sorbitol, bis-1,3,2,4-dibenzylidene 2'-bromo-3 '-Hydroxypropyl sorbitol, bis-1,3:2,4-(3'-bromo-4'-ethylbenzylidene) 1-allyl sorbitol, single 2,4-(3 '-Bromo-4'-ethylbenzylidene) 1-allyl sorbitol, bis-1,3:2,4-(4'-ethylbenzylidene)1-allyl sorbitol , bis-1,3:2,4-(3',4'-dimethylbenzylidene)1-methylsorbitol, bis(p-methylbenzylidene)sorbitol, 1,3: 2,4-bis-o-(4-methylbenzylidene)-D-sorbitol or the like. The commercially available nucleating agent of the nonol alcohol type used in the composition of the present invention may, for example, be Millad NX8000 (Milliken Japan), a commercially available crystal nucleating agent of sorbitol, and may, for example, RiKAFAST R-1 (New Japan) Physicochemical), Millad 3988 (Milliken Japan), Gel All E-200 (New Japan Physical and Chemical), Gel All MD (New Japan Physical and Chemical). The phosphate ester nucleating agent may, for example, be aluminum-bis(4,4',6,6'-tetra-tertiarybutyl-2,2'-methylenediphenyl-phosphate)-hydroxide Wait. The commercially available phosphate ester nucleating agent used in the composition of the present invention may, for example, be ADK STAB NA-21 (Asahi Kasei) or ADK STAB NA-71 (Asahi Kasei). The tribasic benzene derivative crystal nucleating agent may, for example, be 1,3,5-tris(2,2-dimethylpropane decylamine) benzene or the like. The commercially available tribasic benzene derivative nucleating agent used in the composition of the present invention may, for example, be IRGACLEARX T386 (BASF Japan). The carboxylic acid metal salt nucleating agent may, for example, be a calcium salt of 1,2-cyclohexanedicarboxylate or the like. Composition of the invention The commercially available carboxylic acid metal salt nucleating agent may, for example, be Hyperform HPN-20E (Milliken Japan) or the like. In particular, it is possible to maintain transparency after secondary processing (heating), and to use a nonol alcohol core. A sorbitol or sorbitol nucleating agent is preferred.

These crystal nucleating agents may be used singly or in combination of two or more.

The ethylene resin composition of the present invention has an ethylene content of 0.3 to 2.0% by weight, preferably 0.4 to 1.6% by weight based on the weight of the polypropylene copolymer. When the ethylene content in the polypropylene copolymer is less than 0.3% by weight, the transparency after heating is particularly deteriorated, and when it exceeds 2.0% by weight, the rigidity is lowered.

The polypropylene resin composition of the present invention has a melt flow rate at 230 ° C of 1 to 8 g/10 min, preferably 2 to 6 g/10 min. When the melt flow rate is less than 1, the formability is poor and the transfer property of the roll is poor, and the transparency is lowered. When the melt flow rate exceeds 8, the drooping property is deteriorated and the impact property is lowered.

Further, the polypropylene resin composition of the present invention may be added with conventional additives and pigments generally used for olefin polymers such as oil and other organic and inorganic pigments.

The polypropylene resin composition of the present invention is particularly suitable for use in a sheet-like molded article. The reason why it is suitable for use in a sheet-like molded article is, for example, preferable sheet formability (extrusion property) and secondary workability (dipping property), and the molded article has good rigidity and sufficient impact strength. Transparent polypropylene resin composition used in the past for sheet-like molded articles The formability, particularly the secondary workability of the sheet, is not sufficient. When the melt flow rate is increased in order to improve the sheet formability, the secondary workability is lowered, and if the melt flow rate is lowered in order to improve the secondary workability, the sheet formability is lowered, which is a correlation. The polypropylene resin composition of the present invention can improve the workability twice, while maintaining transparency and preferable sheet formability.

According to the method of the present invention, a polyolefin composition for a sheet excellent in transparency and mechanical properties, and excellent in sheet formability and secondary workability can be obtained.

Next, a method of producing the polypropylene resin composition of the present invention will be specifically described.

The polypropylene copolymer used in the composition of the present invention can be obtained by a known slurry method (polymerization in a liquid monomer) or gas phase polymerization. Further, a sequential polymerization method may be employed in which a sequential polymerization step of 2 is carried out in the presence of at least two subsequent polymerizations of the polymerizable material formed in the previous polymerization reaction. The polypropylene copolymer is obtained by copolymerizing a propylene monomer and an ethylene monomer by supplying a propylene monomer, an ethylene monomer, hydrogen, and a catalyst.

Further, a method of producing a polypropylene copolymer may be, for example, a method using a polymerization reactor having a gradient of a monomer concentration and polymerization conditions. Such a polymerizer, for example, can be polymerized by gas phase polymerization using at least two polymerization zone junctions. Specifically, in the presence of a catalyst, to rise A monomer is supplied to the polymerization zone formed by the tube to be polymerized, and the monomer is supplied to the downcomer connected to the riser to be polymerized, and the polymer product is recovered under the circulating riser and the downcomer. The method is provided with a mechanism for preventing the gas mixture present in the riser from entering the downcomer in whole or in part. Further, a gas and/or liquid mixture having a composition different from that of the gas mixture present in the riser is introduced into the downcomer.

For the above polymerization method, for example, the method described in JP-A-2002-520426 can be used.

The addition of the crystal nucleating agent, for example, the polymer obtained by polymerization and the crystal nucleating agent, together with the antioxidant, are stirred by a Henschel mixer, a Brabender, etc., and then used at 180 ° C to 280 using an extruder. The °C melt blends, whereby a polypropylene resin composition can be obtained. The addition of the nucleating agent and the antioxidant may also be carried out by polymerization, removal of residual monomers, drying step, and use of the connected extruder.

The polymerization stage is carried out in the presence of a stereospecific Ziegler-Natta catalyst. According to a preferred embodiment, the total polymerization stage is a solid catalyst containing (A) an electron donor compound selected from the group consisting of magnesium, titanium, halogen, and succinic acid ester as an essential component; (B) an organoaluminum compound; C) is carried out in the presence of a catalyst component selected from the external electron donor compound of the ruthenium compound. Catalysts having the above characteristics are known by the patent literature. The polymerization stage can also be formed in the liquid phase, in the gas phase or in the liquid-gas phase. The reaction temperature in the polymerization stage for preparing the polypropylene copolymer may be the same or different, and is preferably in the range of 40 to 100 ° C, more preferably 50 to 90 ° C, still more preferably 70 to 90 ° C. Used to prepare polypropylene copolymerization The pressure at the polymerization stage of the material, when carried out in a liquid monomer, is a pressure which competes with the vapor pressure of the liquid propylene at the operating temperature used, and may also be a small amount of inertness used to supply the catalyst mixture. The vapor pressure of the diluent is adjusted by the overpressure of any monomer and the hydrogen used as the molecular weight regulator.

The polymerization pressure is preferably in the range of 33 to 43 bar when it is carried out in the liquid phase, and is in the range of 5 to 30 bar in the gas phase. A molecular weight modifier conventionally known in the art, such as a chain transfer agent (e.g., hydrogen or ZnEt ₂ ), can also be used.

[Examples]

The examples are disclosed below to further illustrate the invention. Further, each analysis in the examples was carried out in the following manner.

[MFR]

The measurement was carried out in accordance with JIS K 7210 under the conditions of a temperature of 230 ° C and a load of 21.18 N.

[Ethylene concentration of matrix PP]

A sample dissolved in a mixed solvent of 1,2,4-trichlorobenzene/heterohydrobenzene was measured by a ¹³ C-NMR method using JNM LA-400 ( ¹³ C resonance frequency: 100 MHz) manufactured by JEOL Ltd.

[polydispersity index]

The UDS200 manufactured by PaarPhysica Co., Ltd. was used at a temperature of 190 ° C, and was measured by operating at a vibration number increased from 0.1 rad/sec to 100 rad/sec. The value of the polydispersity index is expressed by the equation: PI = 10 ⁵ /Gc (wherein Gc is defined as G'=G" (here, G' is the storage elastic modulus, and G" is the loss elastic modulus. The value of the value (in Pa) is derived from the crossover elastic modulus.

[stiffness]

Use four sides 40mm The single-layer sheet forming machine was formed into a sheet having a thickness of 0.3 mm at a molding temperature of 220 ° C and a cooling roll temperature of 90 ° C, and the rigidity of the sheet was measured in accordance with JIS K7106 in the direction of use (MD) and its perpendicular direction (TD). The average value thereof. The greater the rigidity, the greater the rigidity.

[surface impact strength]

Using a sheet used for evaluation of rigidity, the dart hammer impact strength at 23 ° C was measured in accordance with JIS K7124-1.

[transparency]

The enthalpy measurement was carried out in accordance with JIS K 7136.

The transparency of the heated sheet is measured by the following method: 150 mm × 270 mm fixed to the metal frame, and a thickness of about 0.3 mm. The sheet was placed in an oven for measuring the peeling test at 210 ° C, and after heating for 30 seconds, it was taken out as soon as possible and allowed to cool at room temperature, and left for a while. This sample was subjected to enthalpy measurement in accordance with JIS K 7136.

[dipping]

A sheet of 150 mm × 270 mm and a thickness of about 0.3 mm fixed to a metal frame was placed in an oven set to 210 ° C (about 186 ° C above the equilibrium melting point of polypropylene, which is a temperature near the preheating temperature in vacuum forming), and melted. after the time point when the sheet after _{stretching. 1} t return due to its own weight to the central portion of the sheet of 2cm suspended time period t ₂ (t ₂ -t _1), the evaluation of the drawn. The drooping causes the thickness of the product to be uneven. The longer the drooping time (t ₂ -t ₁ ) is, the more difficult it is to hang down, so that the secondary workability is excellent.

[Formability (Extrusion Machine Torque)]

The formability was evaluated by the electric power used by the extruder motor (the electric power of the motor divided by the number of revolutions) at the time of forming and measuring the rigid sheet. The lower the power used by the motor, the better the formability.

[Example 1] (1) Modulation of solid catalyst components

The solid catalyst component was prepared according to the preparation method described in the examples of JP-A-2011-500907, specifically, as shown below: in a 500-mL 4-neck round bottom flask purged with nitrogen at 0 °C. 250 mL of TiCl ₄ was introduced. Under stirring, 10.0 g of fine spherical MgCl _{2 was added} . 1.8C ₂ H ₅ OH (manufactured according to Example 2 of USP-4399054, but manufactured by operating at 3000 rpm instead of 10000 rpm), and 9.1 mmol of diethyl-2,3-(diisopropyl) ) succinate. The temperature was raised to 100 ° C for 120 minutes. Then, the stirring was stopped, the solid product was allowed to settle, and the supernatant liquid was sucked out. Next, the following operation was repeated twice: a new 250 mL of new TiCl _{4 was added} , and the mixture was reacted at 120 ° C for 60 minutes, and the supernatant was aspirated. The solid was washed 6 times with anhydrous hexane (6 x 100 mL) at 60 °C.

(2) Polymerization and manufacture of components [Example 1]

The polypropylene resin composition of the present invention is produced by the following method: using the above solid catalyst, triethylamine (TEAL) and diisopropyldimethoxydecane (DIPMS) to make TEAL relative to the solid catalyst. The mass ratio was 11, and the mass ratio of TEAL/DIPMS was 3, and the contact was made at 12 ° C for 24 minutes. The obtained catalyst system was kept in suspension in a liquid state at 20 ° C for 5 minutes to carry out preliminary polymerization.

The obtained preliminary polymer was introduced into a polymerization reactor to polymerize a polypropylene copolymer (propylene/ethylene copolymer). At this time, the ethylene concentration and the hydrogen concentration (ethylene content, used for the purpose of adjusting the MFR) in the polymerization reactor were set to the values shown in Table 1, and the polypropylene copolymer was obtained by adjusting the polymerization temperature and the polymerization pressure. .

The obtained polypropylene copolymer was simultaneously blended as a nucleating agent, a nonol alcohol-based nucleating agent (Millad NX8000 manufactured by Milliken Japan Co., Ltd.) 0.4 weight %, an antioxidant (B225 manufactured by BASF Co., Ltd.), 0.24% by weight, and a neutralizing agent (calcium stearate) of 0.05% by weight, and the polypropylene resin composition shown in Table 1 was obtained by melt-kneading at 230 ° C using an extruder. .

[Examples 2 to 9]

The MFR of the polypropylene copolymer (Examples 2, 3, 5, 6, 8, 9) was adjusted by changing the hydrogen concentration of the polymerization reactor to the values shown in Table 1. Further, when determining the hydrogen concentration, the ethylene concentration of the polymerization reactor is considered. Further, in Examples 4 to 9, the ethylene content of the polypropylene copolymer was adjusted by changing the ethylene concentration of the polymerization reactor to the value shown in Table 1. Otherwise, in the same manner as in Example 1, melt-kneading was carried out to obtain a resin composition.

[Examples 10 to 14]

A crystal nucleating agent different from that of Examples 1 to 9 was added to prepare a polypropylene resin composition. The nucleating agent used was Example 10: RiKAFAST R-1 (sorbitan acetal crystal nucleating agent, New Japan Physicochemical); Example 11: Millad 3988 (sorbitol acetal crystal nucleating agent, Milliken Japan); Example 12: ADK STAB NA-21 (phosphate ester nucleating agent, Asahi Kasei); Example 13: ADK STAB NA-71 (phosphate ester nucleating agent, Asahi Chemical); and Example 14: IRGACLEAR XT386 (triamine benzene derivative nucleating agent, BASF Japan). The polypropylene resin compositions of Examples 10 to 14 were obtained by adding each crystal nucleating agent to the polypropylene copolymer produced in accordance with Example 1.

[Comparative Example 1]

A polymer composition not within the scope of the invention is produced. In Comparative Example 1, the MFR value of the polypropylene resin composition was less than the range of the present invention. The polypropylene used in the polypropylene resin composition of Comparative Example 1 was produced in the same manner as in Example 1 except that the hydrogen concentration of the polymerization reactor was lowered to the values shown in Table 2.

[Comparative Example 2]

A polymer composition not within the scope of the invention is produced. In Comparative Example 2, the value of the MFR of the polypropylene resin composition was less than the range of the present invention. The specific production method of Comparative Example 2 was produced in the same manner as in Example 1 except that the hydrogen concentration of the polymerization reactor was increased to the values shown in Table 2.

[Comparative Example 3]

A polymer composition not within the scope of the invention is produced. In Comparative Example 3, the ethylene content in the polypropylene copolymer was less than the range of the present invention. The specific production method of Comparative Example 3 was produced in the same manner as in Example 1 except that the ethylene concentration in the polymerization reactor was lowered to the value shown in Table 2, and the hydrogen concentration was also decreased.

[Comparative Example 4]

A polymer composition not within the scope of the invention is produced. In Comparative Example 4, the ethylene content in the polypropylene copolymer was less than the range of the present invention. ratio The specific production method of the example 4 is as follows. The same procedure as in the first embodiment is carried out except that the ethylene concentration of the polymerization reactor is increased to the value shown in Table 2, and the hydrogen concentration is also increased.

[Comparative Example 5]

A polymer composition not within the scope of the invention is produced. In Comparative Example 5, the catalyst used in the production of the polypropylene copolymer was not a succinate type but a metal aromatic type. The metal aromatic catalyst used is obtained by the method described in JP-A-2003-517010. The specific production method of the comparative example 5 is as follows: the metal aromatic type catalyst used for the polymerization, and the metal aromatic type complex and the MAO described in the first embodiment of the above-mentioned patent publication are the above-mentioned patent publications. The method carrier described in Example 49.

The polymerization of a polypropylene-based copolymer (propylene/ethylene copolymer) was carried out by the methods described in Examples 55 to 57 of the above-mentioned patent publication. After the hexane solution containing TIBA and propylene were charged in a 20 L autoclave, the above-mentioned supported metal aromatic catalyst was injected. After the polymerization temperature and pressure reach a predetermined value, ethylene is supplied to be polymerized. At this time, a polypropylene copolymer having an ethylene content and an MFR shown in Table 2 was obtained by adjusting the amount of ethylene injected into the autoclave, the polymerization temperature, and the polymerization pressure. A polypropylene resin composition was obtained in the same manner as in Example 1 from the obtained polypropylene copolymer.

[Comparative Example 6]

A polymer composition not within the scope of the invention is produced. Comparative Example 6 The specific production method is as follows: the ethylene concentration of the polymerization reactor is lowered to the value shown in Table 2, and the hydrogen concentration is also reduced to polymerize the polypropylene copolymer without adding a crystal nucleating agent. The same procedure as in Example 1 was carried out.

[Comparative Example 7]

A polymer composition not within the scope of the invention is produced. In Comparative Example 7, the catalyst used for the production of polypropylene was a phthalate. The solid catalyst to be used is obtained by the method described in European Patent No. 674991. The specific production method of Comparative Example 7 is as follows. The solid catalyst used in the polymerization is prepared by the method described in Example 1 of European Patent No. 674991. The solid catalyst was supported on MgCl ₄ by a method described in the above-mentioned patent publication, and a diisopropyl phthalate carrier as an internal donor.

The above solid catalyst, TEAL and DCPMS were contacted at -5 ° C for 5 minutes so that the mass ratio of TEAL to the solid catalyst was 11, and the mass ratio of TEAL/DCPMS was 3. The obtained catalyst system was kept in suspension in a liquid state at 20 ° C for 5 minutes to carry out preliminary polymerization. The obtained preliminary polymer was introduced into a polymerization reactor in the same manner as in Example 1 to polymerize a polypropylene copolymer (propylene/ethylene copolymer). At this time, the ethylene concentration and the hydrogen concentration (the ethylene content, used for the purpose of adjusting the MFR) in the polymerization reactor were set to the values shown in Table 1, and the polymerization polypropylene and the polymerization pressure were adjusted to obtain the intended polypropylene. Copolymer. A polypropylene resin group was obtained in the same manner as in Example 1 from the obtained polypropylene copolymer. Adult.

[Comparative Example 8]

In Comparative Example 8, a commercially available product Higran RS1684 (LyondellBasell) having a polydispersity index of the polypropylene copolymer less than the range of the present invention was used.

The results of the respective examples and comparative examples were summarized in Tables 1 and 2 below.

The polypropylene resin composition of the present invention exhibits excellent workability in both extrusion form and low drop. The sheet-like molded article obtained by molding the polypropylene resin composition of the present invention has both transparency, high rigidity, and sufficient impact strength. a sheet formed using the polypropylene resin composition of the present invention, The transparency after heating (2 times of processing) is also excellent. Therefore, by using the polypropylene resin composition of the present invention, a transparent sheet-like molded article having excellent properties can be efficiently produced.

Claims (3)

A polypropylene resin composition for a sheet comprising a polypropylene copolymer of 99.95 to 99.5% by weight; and a nucleating agent of 0.05 to 0.5% by weight of a polypropylene resin composition for a sheet having the following characteristics: a polypropylene copolymer The polydispersity index is 4.5 to 10, the ethylene content of the polypropylene copolymer is 0.3 to 2.0% by weight based on the weight of the polypropylene copolymer, and the melt flow rate at 230 ° C of the composition is 1 to 8 g. /10 minutes, the polypropylene copolymer is a solid catalyst containing (A) an electron donor compound selected from magnesium, titanium, a halogen, and a succinic acid ester as an essential component, (B) an organoaluminum compound, and (C) A catalyst obtained by copolymerizing propylene with ethylene, which is selected from a catalyst of an external electron donor compound of a ruthenium compound. The resin composition of claim 1, wherein the crystal nucleating agent is selected from the group consisting of a nonol nucleating agent, a sorbitol nucleating agent, a phosphate ester nucleating agent, and a triamino benzene derivative. Nuclear agent, carboxylic acid metal salt nucleating agent and xylitol nucleating agent. A sheet produced by a polypropylene resin composition as claimed in claim 1 or 2.