JP2022143936A - Polypropylene-based resin composition and molded body - Google Patents

Abstract

SOLUTION: A polypropylene-based resin composition is provided which contains 80-90 pts.mass of a propylene-based copolymer (A) satisfying the following requirements (A1) and (A2), 10-20 pts.mass of a propylene-based copolymer (B) satisfying the following requirements (B1) and (B2), and 0.01-0.6 pts.mass of a nucleating agent (D) (the total of the propylene-based copolymer (A) and the propylene-based copolymer (B) is 100 pts.mass), and satisfies the following requirement (C1). (A1) Content of a structural unit derived from ethylene of the propylene-based copolymer (A) is 1.0-3.0 mass%, (A2) limiting viscosity [η](A) in decalin at 135°C of the propylene-based copolymer (A) is 1.0-2.0 dl/g, (B1) a content of a structural unit derived from ethylene of the propylene-based copolymer (B) is 20-40 mass%, (B2) limiting viscosity [η](B) in decalin at 135°C of the propylene-based copolymer (B) is 1.0-2.0 dl/g, and a limiting viscosity ratio [η](B)/[η](A) of the propylene-based copolymer (B) to the propylene-based copolymer (A) is 0.8-1.4. (C1) Melt flow rate (MFR) measured at 230°C and a load of 2.16 kg according to JIS K 7210 is 10-50 g/10 min.EFFECT: A polypropylene-based resin composition can achieve both whitening resistance and impact resistance of a hinge part in applications such as a bottle cap.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a polypropylene resin composition having whitening resistance and impact resistance, and a molded article containing the composition.

In general, propylene resin is inexpensive, has excellent mechanical properties, hygienic compatibility, moldability, and good appearance of molded products. It's being used.

BACKGROUND ART Polypropylene resin, which has excellent heat resistance, is often used for container caps that need to be heated and filled with contents, regardless of whether they are screw caps or hinge-shaped caps, such as beverage container caps and liquid food container caps.

On the other hand, these container caps may be subject to sudden stress loads during the manufacturing process when the product is removed from the mold. In addition, in the hinge-shaped cap, the stress load due to repeated bending is applied to the hinge portion. With a conventional polypropylene resin composition, this sudden stress load and repeated bending stress load are likely to cause whitening, deformation, peeling, etc., and the appearance of the cap itself is impaired. Functionality may deteriorate.

As a technique for preventing product defects typified by such a whitening phenomenon, Patent Document 1 discloses a polypropylene-based resin composition that can provide a beverage bottle cap capable of suppressing the whitening phenomenon caused by stress load during cap molding. things are disclosed. Patent Document 2 discloses a polypropylene resin composition having excellent whitening resistance and impact resistance.

JP-A-2009-84393 Japanese Patent Publication No. 2016-528356

Among caps, in a cap having a hinge portion that repeatedly bends and curves, the whitening phenomenon is particularly likely to occur at the hinge portion.
In addition, polypropylene resins are required to have high impact resistance, but if whitening resistance and impact resistance are to be achieved at the same time, peeling resistance at the hinge portion tends to deteriorate. On the other hand, if an attempt is made to improve the tensile modulus and the whitening resistance in order to improve the delamination resistance of the hinge portion, the impact resistance tends to decrease.

An object of the present invention is to provide a polypropylene-based resin composition that can achieve both whitening resistance and impact resistance particularly in hinge portions in applications such as bottle caps.

The present inventors have found that the above object can be achieved by using a combination of two specific propylene-based copolymers and further blending a nucleating agent, and completed the present invention.
The present invention relates to, for example, the following [1] to [3].
[1] 80 to 90 parts by mass of a propylene copolymer (A) that satisfies the following requirements (A1) and (A2), and 10 to 20 parts by mass of a propylene copolymer (B) that satisfies the following requirements (B1) and (B2): parts by mass, and 0.01 to 0.6 parts by mass of a nucleating agent (D) (provided that the total of the propylene-based copolymer (A) and the propylene-based copolymer (B) is 100 parts by mass) , a polypropylene-based resin composition that satisfies the following requirement (C1).
(A1) The content of structural units derived from ethylene in the propylene-based copolymer (A) is 1.0 to 3.0% by mass.
(A2) The intrinsic viscosity [η] _(A) of the propylene-based copolymer (A) in decalin at 135°C is 1.0 to 2.0 dl/g.
(B1) The content of structural units derived from ethylene in the propylene-based copolymer (B) is 20 to 40% by mass.
(B2) The intrinsic viscosity [η] _(B) of the propylene copolymer (B) in decalin at 135°C is 1.0 to 2.0 dl/g, and the propylene copolymer (B)/propylene copolymer The intrinsic viscosity ratio [η] _(B) /[η] _(A ) of the polymer (A) is from 0.8 to 1.4.
(C1) A melt flow rate (MFR) of 10 to 50 g/10 minutes measured at 230° C. under a load of 2.16 kg according to JIS K 7210.
[2] The polypropylene-based resin composition according to [1], which further satisfies the following requirements (C2) to (C4).
(C2) It has a tensile modulus of elasticity of 800 to 900 MPa as measured according to JIS K 7161.
(C3) High-speed surface impact total energy measured at 0° C. in accordance with ASTM D 3763-02 high-speed impact test method is 20 J or more.
(C4) The change in L value ΔL in L/a/b at the center of the test piece measured before and after dropping a rigid ball onto the center of the test piece obtained by injection molding is 10 or less.
[3] A molded article containing the polypropylene-based resin composition according to [1] or [2].

INDUSTRIAL APPLICABILITY The polypropylene-based resin composition of the present invention can achieve both whitening resistance and impact resistance particularly in hinge portions in applications such as bottle caps.

[Polypropylene resin composition]
The polypropylene-based resin composition of the present invention contains a propylene-based copolymer (A), a propylene-based copolymer (B), and a nucleating agent (D), which will be described later, and satisfies the requirement (C1), which will be described later.

The propylene-based copolymer (A) satisfies the following requirements (A1) and (A2).
(A1) The content of structural units derived from ethylene in the propylene-based copolymer (A) is 1.0 to 3.0% by mass.

The propylene-based copolymer (A) is a copolymer obtained by copolymerizing propylene and ethylene, and preferably has a content of structural units derived from ethylene of 1.0 to 3.0% by mass. is 1.0 to 2.8% by mass, more preferably 1.0 to 2.6% by mass. When the content of structural units derived from ethylene in the propylene-based copolymer (A) is less than 1.0% by mass, peeling resistance and whitening resistance may deteriorate, and the content is more than 3.0% by mass. , deformation of the hinge may occur.

The propylene-based copolymer (A) may contain structural units derived from comonomers other than ethylene as long as it satisfies the above conditions.
(A2) The intrinsic viscosity [η] _(A) of the propylene-based copolymer (A) in decalin at 135°C is 1.0 to 2.0 dl/g.

The propylene-based copolymer (A) has a limiting viscosity [η] _(A) in decalin at 135°C of 1.0 to 2.0 dl/g, preferably 1.1 to 1.8 dl/g, More preferably 1.2 to 1.6 dl/g. When the intrinsic viscosity [η] _(A) is less than 1.0 dl/g, deformation of the hinge portion may easily occur, and when it is more than 2.0 dl/g, peeling resistance and whitening resistance deteriorate. There is a risk.

The propylene-based copolymer (B) satisfies the following requirements (B1) and (B2).
(B1) The content of structural units derived from ethylene in the propylene-based copolymer (B) is 20 to 40% by mass.

The propylene-based copolymer (B) is a copolymer obtained by copolymerizing propylene and ethylene, and the content of structural units derived from ethylene is 20 to 40% by mass, preferably 20 to 35%. % by mass, more preferably 20 to 30% by mass. If the content of structural units derived from ethylene in the propylene-based copolymer (B) is less than 20% by mass, the impact resistance may decrease and deformation of the hinge portion may easily occur. If it is too large, the peeling resistance and whitening resistance may deteriorate.

The propylene-based copolymer (B) may contain structural units derived from comonomers other than ethylene as long as it satisfies the above conditions.
(B2) The intrinsic viscosity [η] _(B) of the propylene copolymer (B) in decalin at 135°C is 1.0 to 2.0 dl/g, and the propylene copolymer (B) and the propylene copolymer The intrinsic viscosity ratio [η] _(B) /[η] _{(A) with the polymer (A)} is 0.8 to 1.4.

The propylene-based copolymer (B) has a limiting viscosity [η] _(B) in decalin at 135°C of 1.0 to 2.0 dl/g, preferably 1.2 to 1.9 dl/g, More preferably 1.4 to 1.8 dl/g. If the intrinsic viscosity [η] _(B) is less than 1.0 dl/g, the impact resistance may decrease, and if it exceeds 2.0 dl/g, the peeling resistance and whitening resistance may deteriorate. .

The intrinsic viscosity ratio [η] _(B) /[η] _{(A) between the propylene-based copolymer (B) and the propylene-based copolymer (A)} is 0.8 to 1.4, preferably 0.8. 9 to 1.4, more preferably 1.0 to 1.4. If the intrinsic viscosity ratio [η] _(B) / [η] _(A) is less than 0.8, the peeling resistance and whitening resistance may deteriorate, and if it is greater than 1.4, the impact resistance will decrease. There is a risk of

The propylene-based copolymer (A) and propylene-based polymer (B) can be produced by the following method.
The method for producing the propylene-based polymer (A) and the propylene-based polymer (B) used in the present invention is not particularly limited. and obtained by copolymerizing ethylene.

The propylene-based polymer (A) and propylene-based polymer (B) are preferably obtained by copolymerizing propylene and ethylene in the presence of a Ziegler-Natta catalyst. This is because a resin having a wide molecular weight distribution and good moldability can be easily obtained.

(Ziegler-Natta catalyst)
The propylene-based polymer (A) and propylene-based polymer (B) used in the present invention can be produced by using a highly stereoregular Ziegler-Natta catalyst. Various known catalysts can be used as the highly stereoregular Ziegler-Natta catalyst. For example, (a) a solid titanium catalyst component containing magnesium, titanium, a halogen and an electron donor, (b) an organometallic compound catalyst component, (c) a cyclopentyl group, a cyclopentenyl group, a cyclopentadienyl group, and A catalyst comprising an organosilicon compound catalyst component having at least one group selected from the group consisting of these derivatives can be used.

The solid titanium catalyst component (a) can be prepared by contacting a magnesium compound (a-1), a titanium compound (a-2) and an electron donor (a-3). Examples of the magnesium compound (a-1) include magnesium compounds having reducing ability such as magnesium compounds having a magnesium-carbon bond or magnesium-hydrogen bond, magnesium halides, alkoxymagnesium halides, allyloxymagnesium halides, alkoxymagnesium, Magnesium compounds having no reducing ability, such as allyloxymagnesium and magnesium carboxylates, can be mentioned.

When preparing the solid titanium catalyst component (a), it is preferable to use, for example, a tetravalent titanium compound represented by the following formula (1) as the titanium compound (a-2).
Ti(OR)gX4 _{-g (} 1)
(In Formula (1), R is a hydrocarbon group, X is a halogen atom, and 0≤g≤4.)

Specifically, titanium tetrahalides such as TiCl ₄ , TiBr ₄ and TiI ₄ ; Ti(OCH ₃ )Cl ₃ , Ti(OC ₂ H ₅ )Cl ₃ , Ti(On-C ₄ H ₉ )Cl ₃ , Ti( _OC2H5 ) _{Br3 ,} Ti(O _- iso _{- C4H9} ) _Br3 ; Ti _{( OCH3} ) _2Cl2 , Ti _{( OC2H5} )2Cl; ₂ , Ti( _{On - C4H9} ) _{2Cl2 ,} Ti _{( OC2H5} ) _2Br2 ; Ti ₍ OCH3) _3Cl , Ti _{( OC2H5} ). monohalogenated trialkoxytitanium such as ₃ Cl, Ti(On-C ₄ H ₉ ) ₃ Cl, Ti(OC ₂ H ₅ ) ₃ Br; Ti(OCH ₃ ) ₄ , Ti(OC ₂ H ₅ ) ₄ , Ti(O-n-C ₄ H ₉ ) ₄ , Ti(O-iso-C ₄ H ₉ ) ₄ , Ti(O-2-ethylhexyl) ₄ and the like.

Examples of the electron donor (a-3) used in the preparation of the solid titanium catalyst component (a) include alcohols, phenols, ketones, aldehydes, esters of organic or inorganic acids, organic acid halides, ethers, acid Amides, acid anhydrides, ammonia, amines, nitriles, isocyanates, nitrogen-containing cyclic compounds, oxygen-containing cyclic compounds, and the like.

When the magnesium compound (a-1), titanium compound (a-2) and electron donor (a-3) as described above are brought into contact with each other, other reaction agents such as silicon, phosphorus and aluminum are allowed to coexist. Alternatively, a support may be used to prepare a support-supported solid titanium catalyst component (a).

The solid titanium catalyst component (a) can be prepared by any method including known methods, some of which are briefly described below.
(1) A hydrocarbon solution of a magnesium compound (a-1) containing an electron donor (liquefying agent) (a-3) is brought into contact with an organometallic compound to precipitate a solid, after or while the solid is precipitated. A method of contact-reacting with a titanium compound (a-2).
(2) A method of contacting and reacting a complex composed of a magnesium compound (a-1) and an electron donor (a-3) with an organometallic compound, and then contacting and reacting a titanium compound (a-2).
(3) A method of contact-reacting a titanium compound (a-2) and an electron donor (a-3) with a contact product of an inorganic carrier and an organomagnesium compound (a-1). At this time, the contact material may be previously contacted with the halogen-containing compound and/or the organometallic compound.
(4) magnesium compound (a-1) supported support from a mixture of magnesium compound (a-1) solution containing liquefying agent and optionally hydrocarbon solvent, electron donor (a-3) and support After obtaining and then contacting the titanium compound (a-2).
(5) A method of contacting a carrier with a solution containing a magnesium compound (a-1), a titanium compound (a-2), an electron donor (a-3), and optionally a hydrocarbon solvent.
(6) A method of contacting a liquid organomagnesium compound (a-1) with a halogen-containing titanium compound (a-2). At this time, the electron donor (a-3) is used at least once.
(7) A method of contacting a liquid organomagnesium compound (a-1) with a halogen-containing compound and then contacting the titanium compound (a-2). The electron donor (a-3) is used at least once in this process.
(8) A method of contacting an alkoxy group-containing magnesium compound (a-1) with a halogen-containing titanium compound (a-2). At this time, the electron donor (a-3) is used at least once.
(9) A method of contacting a complex comprising an alkoxy group-containing magnesium compound (a-1) and an electron donor (a-3) with a titanium compound (a-2).
(10) A method of contacting a complex composed of an alkoxy group-containing magnesium compound (a-1) and an electron donor (a-3) with an organometallic compound, followed by contact reaction with a titanium compound (a-2).
(11) A method of contacting and reacting the magnesium compound (a-1), the electron donor (a-3) and the titanium compound (a-2) in any order. Prior to this reaction, each component may be pretreated with a reaction aid such as an electron donor (a-3), an organometallic compound, or a halogen-containing silicon compound.
(12) A liquid magnesium compound (a-1) having no reducibility and a liquid titanium compound (a-2) are reacted in the presence of an electron donor (a-3) to obtain solid magnesium. - A method of depositing a titanium composite.
(13) A method of further reacting the reaction product obtained in (12) above with a titanium compound (a-2).
(14) A method of further reacting the reaction product obtained in (11) or (12) above with an electron donor (a-3) and a titanium compound (a-2).
(15) The solid material obtained by pulverizing the magnesium compound (a-1), the titanium compound (a-2) and the electron donor (a-3) is subjected to halogen, halogen compound or aromatic carbonization. How to treat with either hydrogen. In this method, the magnesium compound (a-1) alone, the complex compound consisting of the magnesium compound (a-1) and the electron donor (a-3), or the magnesium compound (a-1) and titanium A step of pulverizing the compound (a-2) may be included. After pulverization, pretreatment with a reaction aid may be carried out, followed by treatment with a halogen or the like. As a reaction aid, an organic metal compound or a halogen-containing silicon compound is used.
(16) A method of contacting the titanium compound (a-2) after pulverizing the magnesium compound (a-1). When grinding and/or contacting the magnesium compound (a-1), the electron donor (a-3) is optionally used together with a reaction aid.
(17) A method of treating the compound obtained in (11) to (16) above with a halogen, a halogen compound, or an aromatic hydrocarbon.
(18) A method of contacting the contact reaction product of the metal oxide, organomagnesium (a-1) and halogen-containing compound with an electron donor (a-3) and preferably a titanium compound (a-2).
(19) A magnesium compound (a-1) such as a magnesium salt of an organic acid, alkoxymagnesium, or aryloxymagnesium is combined with a titanium compound (a-2), an electron donor (a-3), and, if necessary, a halogen-containing carbonization Method of contacting with hydrogen.
(20) A method of contacting a hydrocarbon solution containing a magnesium compound (a-1) and an alkoxytitanium with an electron donor (a-3) and optionally a titanium compound (a-2). At this time, it is preferable to coexist with a halogen-containing compound such as a halogen-containing silicon compound.
(21) A liquid magnesium compound (a-1) having no reducing ability is reacted with an organometallic compound to deposit a solid magnesium-metal (aluminum) complex, and then an electron donor (a- 3) and a method of reacting the titanium compound (a-2).

The organometallic compound catalyst component (b) preferably contains a metal selected from Groups I to III of the periodic table. Specifically, the following organoaluminum compounds, Group I metals and aluminum complex alkyl compounds with and organometallic compounds of Group II metals.

Formula R ¹ _m Al(OR ² ) _n H _p X _q (wherein R ¹ and R ² are hydrocarbon groups containing usually 1 to 15, preferably 1 to 4 carbon atoms, and they are the same but can be different.
X represents a halogen atom, 0<m≦3, n is 0≦n<3, p is 0≦p<3, q is a number of 0≦q<3, and m+n+p+q=3. ) an organoaluminum compound (b-1) represented by

A complex alkylate (b-2) of a Group I metal and aluminum represented by the formula M ¹ AlR ¹ ₄ (wherein M ¹ is Li, Na or K, and R ¹ is the same as above) .
Group ^II or Group ^{III dialkyl compounds ( b} -3).

Examples of the organoaluminum compound (b-1) include R ¹ _m Al(OR ² ) _3-m (R ¹ and R ² are the same as above, and m is preferably a number satisfying 1.5≦m≦3 a compound represented by R ¹ _m AlX _3-m (R ¹ is the same as defined above, X is halogen, and m is preferably 0<m<3), A compound represented by R ¹ _m AlH _3-m (R ¹ is the same as defined above and m is preferably 2≦m<3), R ¹ _m Al(OR ² ) _n X _q (R ¹ and R ² is the same as above, X is a halogen, 0<m≦3, 0≦n<3, 0≦q<3, and m+n+q=3). can.

Specific examples of the organosilicon compound catalyst component (c) include organosilicon compounds represented by the following formula (2).
^SiR1R2n (OR3) ³ _{-n (} ² )
(In formula (2), n is 0, 1 or 2, R ¹ is a group selected from the group consisting of cyclopentyl group, cyclopentenyl group, cyclopentadienyl group and derivatives thereof, R ² and R ³ are hydrocarbon indicates the group.)

In formula (2), specific examples of R ¹ include cyclopentyl, 2-methylcyclopentyl, 3-methylcyclopentyl, 2-ethylcyclopentyl, 3-propylcyclopentyl, 3-isopropylcyclopentyl, 3 -butylcyclopentyl group, 3-tert-butylcyclopentyl group, 2,2-dimethylcyclopentyl group, 2,3-dimethylcyclopentyl group, 2,5-dimethylcyclopentyl group, 2,2,5-trimethylcyclopentyl group, 2,3 ,4,5-tetramethylcyclopentyl group, 2,2,5,5-tetramethylcyclopentyl group, 1-cyclopentylpropyl group, 1-methyl-1-cyclopentylethyl group and other cyclopentyl groups or derivatives thereof; 2-cyclopentenyl group, 3-cyclopentenyl group, 2-methyl-1-cyclopentenyl group, 2-methyl-3-cyclopentenyl group, 3-methyl-3-cyclopentenyl group, 2-ethyl-3-cyclopentenyl 2,2-dimethyl-3-cyclopentenyl group, 2,5-dimethyl-3-cyclopentenyl group, 2,3,4,5-tetramethyl-3-cyclopentenyl group, 2,2,5,5 -Cyclopentenyl groups such as tetramethyl-3-cyclopentenyl group or derivatives thereof; 1,3-cyclopentadienyl group, 2,4-cyclopentadienyl group, 1,4-cyclopentadienyl group, 2- methyl-1,3-cyclopentadienyl group, 2-methyl-2,4-cyclopentadienyl group, 3-methyl-2,4-cyclopentadienyl group, 2-ethyl-2,4-cyclopenta dienyl group, 2,2-dimethyl-2,4-cyclopentadienyl group, 2,3-dimethyl-2,4-cyclopentadienyl group, 2,5-dimethyl-2,4-cyclopentadienyl group cyclopentadienyl groups or derivatives thereof such as 2,3,4,5-tetramethyl-2,4-cyclopentadienyl groups; and indenyl as derivatives of cyclopentyl, cyclopentenyl or cyclopentadienyl groups. group, 2-methylindenyl group, 2-ethylindenyl group, 2-indenyl group, 1-methyl-2-indenyl group, 1,3-dimethyl-2-indenyl group, indanyl group, 2-methylindenyl group , 2-indanyl group, 1,3-dimethyl-2-indanyl group, 4,5,6,7-tetrahydroindenyl group, 4,5,6,7-tetrahydro-2-indenyl 4,5,6,7-tetrahydro-1-methyl-2-indenyl group, 4,5,6,7-tetrahydro-1,3-dimethyl-2-indenyl group and fluorenyl group.

In formula (2), specific examples of hydrocarbon groups for R ² and R ³ include hydrocarbon groups such as alkyl groups, cycloalkyl groups, aryl groups and aralkyl groups. When two or more R ² or R ³ are present, R ² or R ³ may be the same or different, and R ² and R ³ may be the same or different. In formula (2), R ¹ and R ² may be bridged by an alkylene group or the like.

Organosilicon compounds represented by formula (2) wherein R ¹ is a cyclopentyl group, R ² is an alkyl group or a cyclopentyl group, and R ³ is an alkyl group, especially a methyl group or an ethyl group. is preferred.

Specific examples of organosilicon compounds represented by formula (2) include cyclopentyltrimethoxysilane, 2-methylcyclopentyltrimethoxysilane, 2,3-dimethylcyclopentyltrimethoxysilane, and 2,5-dimethylcyclopentyltrimethoxysilane. Trialkoxysilanes such as silane, cyclopentyltriethoxysilane, cyclopentenyltrimethoxysilane, 3-cyclopentenyltrimethoxysilane, 2,4-cyclopentadienyltrimethoxysilane, indenyltrimethoxysilane, and fluorenyltrimethoxysilane Class: dicyclopentyldimethoxysilane, bis(2-methylcyclopentyl)dimethoxysilane, bis(3-tert-butylcyclopentyl)dimethoxysilane, bis(2,3-dimethylcyclopentyl)dimethoxysilane, bis(2,5-dimethylcyclopentyl) Dimethoxysilane, dicyclopentyldiethoxysilane, dicyclopentenyldimethoxysilane, di(3-cyclopentenyl)dimethoxysilane, bis(2,5-dimethyl-3-cyclopentenyl)dimethoxysilane, di-2,4-cyclopentadisilane enyldimethoxysilane, bis(2,5-dimethyl-2,4-cyclopentadienyl)dimethoxysilane, bis(1-methyl-1-cyclopentylethyl)dimethoxysilane, cyclopentylcyclopentenyldimethoxysilane, cyclopentylcyclopentadienyldimethoxysilane Silane, diindenyldimethoxysilane, bis(1,3-dimethyl-2-indenyl)dimethoxysilane, cyclopentadienylindenyldimethoxysilane, difluorenyldimethoxysilane, cyclopentylfluorenyldimethoxysilane, indenylfluorenyl dialkoxysilanes such as dimethoxysilane; tricyclopentylmethoxysilane, tricyclopentenylmethoxysilane, tricyclopentadienylmethoxysilane, tricyclopentylethoxysilane, dicyclopentylmethylmethoxysilane, dicyclopentylethylmethoxysilane, dicyclopentylmethylethoxysilane , cyclopentyldimethylmethoxysilane, cyclopentyldiethylmethoxysilane, cyclopentyldimethylethoxysilane, bis(2,5-dimethylcyclopentyl)cyclopentylmethoxysilane, dicyclopentylcyclopentenylmethoxysilane, dicyclopentylcyclopentadie monoalkoxysilanes such as nilmethoxysilane and diindenylcyclopentylmethoxysilane; and ethylenebiscyclopentyldimethoxysilane and the like.

When propylene is polymerized using a catalyst comprising the solid titanium catalyst component (a), the organometallic compound catalyst component (b), and the organosilicon compound catalyst component (c) as described above, prepolymerization is carried out in advance. can also The prepolymerization polymerizes the olefin in the presence of the solid titanium catalyst component (a), the organometallic compound catalyst component (b), and optionally the organosilicon compound catalyst component (c).

As the prepolymerized olefin, an α-olefin having 2 to 8 carbon atoms can be used. Specifically, linear olefins such as ethylene, propylene, 1-butene, 1-octene; 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4- methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, etc. can be used. These may be copolymerized.

The prepolymerization is desirably carried out so that about 0.1 to 1000 g, preferably about 0.3 to 500 g of polymer is produced per 1 g of the solid titanium catalyst component (a). If the prepolymerization amount is too large, the production efficiency of the (co)polymer in the main polymerization may decrease. In the prepolymerization, the catalyst can be used at a much higher concentration than in the system in the main polymerization. When propylene is continuously polymerized in multiple stages using the above catalyst, propylene and ethylene may be copolymerized in any stage or in all stages as long as the object of the present invention is not impaired. good.

In the case of continuous multi-stage polymerization, polypropylene is produced by homopolymerizing propylene or copolymerizing propylene and ethylene in each stage. In the main polymerization, about 0.0001 to 50 millimoles, preferably about 0.001 to 10 millimoles of the solid titanium catalyst component (a) (or prepolymerization catalyst) is converted to titanium atoms per liter of polymerization volume. It is desirable to use it in quantity. The organometallic compound catalyst component (b) is desirably used in an amount of about 1 to 2000 mol, preferably about 2 to 500 mol, in terms of metal atom weight per 1 mol of titanium atom in the polymerization system. The organosilicon compound catalyst component (c) is desirably used in an amount of about 0.001 to 50 mol, preferably about 0.01 to 20 mol, per 1 mol of the metal atom in the organometallic compound catalyst component (b).

(Manufacturing method of propylene-based polymer (A))
The propylene-based polymer (A) used in the present invention is obtained by copolymerizing propylene and ethylene in the presence of the above-mentioned metallocene compound-containing catalyst or in the presence of a Ziegler-Natta catalyst.

The polymerization may be carried out by any of a gas phase polymerization method, a liquid phase polymerization method such as a solution polymerization method and a suspension polymerization method, and each stage may be carried out by a separate method. Further, the polymerization may be conducted by either a continuous system or a semi-continuous system, and each stage may be divided into a plurality of polymerization vessels, for example, 2 to 10 polymerization vessels. Industrially, it is most preferable to carry out polymerization by a continuous method. It is possible to suppress the generation of high-molecular-weight components, which are duplicated components that have an unfavorable negative effect on the properties.

As the polymerization medium, inert hydrocarbons may be used, and liquid propylene may be used as the polymerization medium. The polymerization conditions for each stage are such that the polymerization temperature is in the range of about −50 to +200° C., preferably about 20 to 100° C., and the polymerization pressure is normal pressure to 10 MPa (gauge pressure), preferably about 0.2 to 5 MPa. (gauge pressure).

When producing the propylene-based polymer (A), [Step 1] described below is carried out.
In [Step 1], propylene and a required amount of ethylene are copolymerized at a polymerization temperature of 0 to 100° C. and a polymerization pressure of normal pressure to 5 MPa gauge pressure. In [Step 1], the propylene-based copolymer produced in [Step 1] satisfies the requirement (A1) by reducing the feed amount of ethylene relative to propylene. In addition, if necessary, a chain transfer agent typified by hydrogen gas is introduced to adjust the intrinsic viscosity [η] of the propylene-based copolymer produced in [Step 1], and the propylene copolymer produced in [Step 1]. A propylene-based copolymer that satisfies requirement (A2).

Requirement (A1) can be adjusted by adjusting the propylene feed amount and the ethylene feed amount when performing [Step 1]. That is, by increasing the amount of ethylene feed relative to the amount of propylene feed, the mass of structural units derived from ethylene in the polypropylene copolymer (A) can be increased. Further, by reducing the feed amount of ethylene with respect to the feed amount of propylene, the mass of structural units derived from ethylene in the polypropylene copolymer (A) can be reduced.

Requirement (A2) can be adjusted by adjusting the feed amount of hydrogen gas used as a chain transfer agent when performing [Step 1]. In other words, the limiting viscosity [η] can be reduced by increasing the feed amount of hydrogen gas with respect to the feed amount of propylene or the feed amount of propylene and ethylene when feeding propylene and ethylene. Intrinsic viscosity [η] can be increased by reducing the feed amount of hydrogen gas relative to the feed amount of propylene and ethylene, or when propylene and ethylene are fed.
After completion of the polymerization, the propylene-based copolymer (A) is obtained as a powder by carrying out known post-treatment steps such as a catalyst deactivation treatment step, a catalyst residue removal step and a drying step, if necessary.

(Manufacturing method of propylene-based polymer (B))
The propylene-based polymer (B) used in the present invention is obtained by copolymerizing propylene and ethylene in the presence of the above-mentioned metallocene compound-containing catalyst or in the presence of a Ziegler-Natta catalyst.

The polymerization may be carried out by any of a gas phase polymerization method, a liquid phase polymerization method such as a solution polymerization method and a suspension polymerization method, and each stage may be carried out by a separate method. Further, the polymerization may be conducted by either a continuous system or a semi-continuous system, and each stage may be divided into a plurality of polymerization vessels, for example, 2 to 10 polymerization vessels. Industrially, it is most preferable to carry out polymerization by a continuous method. It is possible to suppress the generation of high-molecular-weight components, which are duplicated components that have an unfavorable negative effect on the properties.

As the polymerization medium, inert hydrocarbons may be used, and liquid propylene may be used as the polymerization medium. The polymerization conditions for each stage are such that the polymerization temperature is in the range of about −50 to +200° C., preferably about 20 to 100° C., and the polymerization pressure is normal pressure to 10 MPa (gauge pressure), preferably about 0.2 to 5 MPa. (gauge pressure).

When producing the propylene-based polymer (B), [Step 2] described below is carried out.
In [Step 2], propylene and a required amount of ethylene are copolymerized at a polymerization temperature of 0 to 100° C. and a polymerization pressure of normal pressure to 5 MPa gauge pressure. In [Step 2], the propylene-based copolymer produced in [Step 2] satisfies the requirement (B1) by reducing the feed amount of ethylene relative to propylene. In addition, if necessary, a chain transfer agent typified by hydrogen gas is also introduced to adjust the intrinsic viscosity [η] of the propylene-based copolymer produced in [Step 2], and the propylene copolymer produced in [Step 2]. The propylene-based copolymer that satisfies the requirement (B2).

Requirement (B1) can be adjusted by adjusting the amount of propylene feed and the amount of ethylene feed when performing [Step 2]. That is, by increasing the amount of ethylene feed relative to the amount of propylene feed, the mass of structural units derived from ethylene in the polypropylene copolymer (B) can be increased. Further, by reducing the feed amount of ethylene with respect to the feed amount of propylene, the mass of structural units derived from ethylene in the polypropylene copolymer (B) can be reduced.

Requirement (B2) can be adjusted by the feed amount of hydrogen gas used as a chain transfer agent when performing [Step 2]. In other words, the limiting viscosity [η] can be reduced by increasing the feed amount of hydrogen gas with respect to the feed amount of propylene or the feed amount of propylene and ethylene when feeding propylene and ethylene. Intrinsic viscosity [η] can be increased by reducing the feed amount of hydrogen gas relative to the feed amount of propylene and ethylene, or when propylene and ethylene are fed.
After completion of the polymerization, the propylene-based copolymer (B) is obtained as a powder by carrying out known post-treatment steps such as a catalyst deactivation treatment step, a catalyst residue removal step and a drying step, if necessary.

Alternatively, a propylene-based polymer may be obtained by continuously performing two steps ([step 1] and [step 2]) in a reactor in which two or more polymerization vessels are connected in series. I don't mind. In that case, the propylene-based polymer obtained in [Step 1] is the propylene-based polymer (A), and the propylene-based polymer obtained in [Step 2] is the propylene-based polymer (B).

When two steps ([step 1] and [step 2]) are performed continuously, [step 1] can be performed in each polymerization apparatus using a polymerization apparatus in which two or more reactors are connected in series, [Step 2] can be carried out in each polymerization apparatus using a polymerization apparatus in which two or more reactors are connected in series.

Requirements (A1), (A2), (B1) and (B2) can be adjusted as follows.
Requirements (A1) and (B1) can be adjusted by adjusting the propylene feed amount and the ethylene feed amount when performing [Step 1] and [Step 2]. That is, by increasing the amount of ethylene feed relative to the amount of propylene feed, the mass of structural units derived from ethylene in the propylene-based copolymer can be increased. Also, by reducing the feed amount of ethylene with respect to the feed amount of propylene, the mass of structural units derived from ethylene in the propylene-based copolymer can be reduced.

Requirements (A2) and (B2) are the feed amount of propylene when performing [Step 1] and [Step 2] or the feed amount of propylene and ethylene when feeding propylene and ethylene, as a chain transfer agent Adjustment is possible by adjusting the feed amount of hydrogen gas. When propylene feed rate or propylene and ethylene are fed, the limiting viscosity [η] can be lowered by increasing the hydrogen feed rate relative to the propylene and ethylene feed rates. In the case of feeding, the intrinsic viscosity [η] can be increased by reducing the feed amount of hydrogen with respect to the feed amounts of propylene and ethylene.

As the propylene copolymer (A) and the propylene-based copolymer (B), existing commercially available products can be used.
When two steps ([step 1] and [step 2]) are performed continuously, the ratio of the polypropylene copolymer (A) and the polypropylene copolymer (B) is the same as the above [step 1] and [step 2]. It can be prepared by adjusting the polymerization time. That is, by making the polymerization time of [Step 1] longer than the polymerization time of [Step 2], the proportion of propylene copolymer (A) is increased and the proportion of propylene copolymer (B) is decreased. can do Also, by making the polymerization time of [Step 2] longer than the polymerization time of [Step 1], the proportion of propylene copolymer (A) is decreased and the proportion of propylene copolymer (B) is increased. I can do things.

The nucleating agent (D) is not particularly limited, and includes carboxylic acid metal salt nucleating agents such as para-tert-butylbenzoic acid aluminum salt and sodium benzoate, and sorbitols such as dibenzylidene sorbitol and di-alkyl-benzylidene sorbitol. nucleating agents, phosphate ester metal salt nucleating agents such as phosphate ester sodium salts, and the like. Among these, ADEKA STAB NA11 (manufactured by ADEKA Co., Ltd.), which is a phosphate ester metal salt nucleating agent, and AL-PTBBA (manufactured by Dainippon Ink and Chemicals, Inc.), which is a carboxylic acid metal salt nucleating agent, etc. It can be used preferably.

In the polypropylene-based resin composition of the present invention, the contents of the propylene-based copolymer (A), the propylene-based copolymer (B) and the nucleating agent (D) are Based on 100 parts by mass of the copolymer (B) in total, 80 to 90 parts by mass of the propylene copolymer (A), 10 to 20 parts by mass of the propylene copolymer (B), and 0.2 parts by mass of the nucleating agent (D). 01 to 0.6 parts by mass. The content of the propylene-based copolymer (A) is preferably 81-89 parts by mass, more preferably 82-88 parts by mass. The content of the propylene-based copolymer (B) is preferably 11 to 19 parts by mass, more preferably 12 to 18 parts by mass. The content of the nucleating agent (D) is preferably 0.03 to 0.3 parts by mass, more preferably 0.05 to 0.2 parts by mass.

When the contents of the propylene-based copolymer (A), the propylene-based copolymer (B), and the nucleating agent (D) are within the above ranges, the polypropylene-based resin composition has both whitening resistance and impact resistance. is obtained.

The polypropylene-based resin composition may further contain pigments, vitamins, antioxidants, heat stabilizers, weather stabilizers, slip agents, antiblocking agents, petroleum resins, Additives such as mineral oil may be included.

The polypropylene-based resin composition of the present invention satisfies the following requirement (C1).
(C1) According to JIS K 7210, the melt flow rate (MFR) measured at 230° C. under a load of 2.16 kg is 10 to 50 g/10 minutes.

The polypropylene resin composition of the present invention has a melt flow rate (MFR) of 10 to 50 g/10 min, preferably 15 to 50 g/ 10 minutes, more preferably 20 to 50 g/10 minutes.

When the melt flow rate of the polypropylene-based resin composition of the present invention is less than 10, the orientation at the hinge portion during injection becomes strong, and peeling and whitening tend to occur. If the melt flow rate is more than 50, the orientation at the hinge portion during injection is weakened, which tends to cause deformation.

The polypropylene-based resin composition of the present invention contains the propylene-based copolymer (A), the propylene-based copolymer (B), and the nucleating agent (D) in the above-described content ratio, and satisfies the above requirement (C1). As a result, in applications such as bottle caps, both whitening resistance and impact resistance of the hinge portion can be achieved. The reason why such an effect is obtained is presumed as follows.

By reducing the difference in intrinsic viscosity between the propylene-based copolymer (A) and the propylene-based copolymer (B), the dispersed particle size can be appropriately controlled, and the separation of the two-component interface due to bending of the hinge or impact can be prevented. can be suppressed, resulting in improved whitening resistance and impact resistance.

The propylene-based copolymer (A) can improve the interfacial strength with the propylene-based copolymer (B) and obtain flexibility by including structural units derived from ethylene in an appropriate ratio. As a result, it satisfies the tight contact with the bottle portion and the sealability of the contents when the cap is closed, which are required for the cap.

If the above conditions are satisfied, the material becomes too flexible, which causes the problem of weakening the opening/closing torque. achieve justification.

The polypropylene-based resin composition of the present invention preferably further satisfies the following requirements (C2) to (C4).
(C2) It has a tensile modulus of elasticity of 800 to 900 MPa as measured according to JIS K 7161.
The polypropylene-based resin composition of the present invention preferably has a tensile elastic modulus of 800 to 900 MPa as measured according to JIS K 7161.
If the tensile modulus of the polypropylene-based resin composition of the present invention is less than 800 MPa, deformation tends to occur, and if it exceeds 900 MPa, peeling or whitening tends to occur.

(C3) High-speed surface impact total energy measured at 0° C. in accordance with ASTM D 3763-02 high-speed impact test method is 20 J or more.
The polypropylene-based resin composition of the present invention preferably has a high-speed surface impact total energy of 20 J or more measured in a 0° C. environment according to ASTM D 3763-02 high-speed impact test method.
The polypropylene-based resin composition of the present invention tends to have insufficient impact resistance when the high-speed surface impact total energy is less than 20J.

(C4) A change in L value in L/a/b at the center of the test piece measured before and after dropping a rigid ball onto the center of the test piece obtained by injection molding is Δ10 or less.
In the polypropylene-based resin composition of the present invention, a rigid ball is dropped onto the center of a test piece obtained by injection molding, and the L value change ΔL in L/a/b at the center of the test piece measured before and after the drop is 10 or less. Preferably.

If the ΔL is greater than 10, the polypropylene-based resin composition of the present invention tends to have insufficient whitening resistance.
The method for producing the polypropylene-based resin composition used in the present invention is not particularly limited. Various components to be used as appropriate are blended in a mixer such as a Henschel mixer, a Banbury mixer, or a tumbler mixer, and then kneaded using a single-screw or twin-screw extruder to obtain pellets.

A composition that satisfies the above requirements (C1) to (C4) can be produced by referring to the methods described in Examples below.

[Molded body]
The molded article of the present invention contains the polypropylene-based resin composition. The molded article of the present invention can be obtained by molding the polypropylene-based resin composition by various molding methods. Since the polypropylene-based resin composition has excellent whitening resistance and impact resistance as described above, it can be used for various molded articles, and is particularly suitable for bottle caps having a hinge portion. can.

A bottle cap having a hinge portion is particularly prone to whitening at the hinge portion that is repeatedly bent and curved. Furthermore, the impact resistance is high.

The method of molding the bottle cap is not particularly limited, but injection molding or compression molding is usually employed.

EXAMPLES Next, the present invention will be described in detail based on examples, but the present invention is not limited to these examples.
Methods for measuring physical properties in Examples and Comparative Examples are as follows.

(Content of constituent units derived from ethylene)
The weight of the structural unit derived from ethylene in the propylene-based polymer (A) and the propylene-based polymer (B) was determined by measuring and calculating as follows based on ¹³ CNMR measurement.
¹³ C-NMR measurement conditions Measurement device: JEOL LA400 type nuclear magnetic resonance device Measurement mode: BCM (Bilevel Complete decoupling)
Observation frequency: 100.4MHz
Observation range: 17006.8Hz
Pulse width: C nucleus 45° (7.8 μs)
Pulse repetition time: 5 seconds Sample tube: 5 mmφ
Sample tube rotation speed: 12 Hz
Cumulative number of times: 20000 times Measurement temperature: 125°C
Solvent: 1,2,4-trichlorobenzene: 0.35 ml/heavy benzene: 0.2 ml
Sample amount: about 40 mg

From the spectrum obtained by the measurement, the ratio of the monomer chain distribution (triad (triad) distribution) was determined according to the following document (1), and the molar fraction of the ethylene-derived structural units of the propylene-based polymer. (mol%) (hereinafter referred to as E (mol%)) and the molar fraction (mol%) of structural units derived from propylene (hereinafter referred to as P (mol%)) were calculated. The obtained E (mol%) and P (mol%) are converted to weight% according to the following (formula 1), and the weight (% by weight) of the structural unit derived from ethylene in Dsol of the propylene-based polymer (hereinafter E ( wt%)) was calculated.

Reference (1): Kakugo, M.; Naito, Y.; Mizunuma, K.; Miyatake, T., Carbon-13 NMR determine
Aation of monomer sequence distribution in ethylene-propylene copolymers prepared
with delta-titanium trichloride-diethylaluminum chloride. Macromolecules 1982,
15, (4), 1150-1152
E (wt%) = E (mol%) x 28 x 100/[P (mol%) x 42 + E (mol%) x 28] (Formula 1)

(Intrinsic viscosity [η])
Measured at 135° C. using decalin solvent. About 20 mg of the sample was dissolved in 15 ml of decalin, and the specific viscosity η _sp was measured in an oil bath at 135°C. 5 ml of the decalin solvent was added to the decalin solution to dilute it, and then the specific viscosity η _sp was measured in the same manner. This dilution operation was repeated twice, and the value of η _sp /C when the concentration (C) was extrapolated to 0 was determined as the intrinsic viscosity.
[η]=lim(η _sp /C) (C→0).

(Melt flow rate (MFR))
The melt flow rate was measured at 230° C. under a load of 2.16 kg according to JIS K 7210.

(tensile modulus)
The tensile modulus was measured according to JIS K 7161 using a type A test piece.

(high-speed surface impact total energy)
A polypropylene-based resin composition was injection-molded to prepare a test piece having a length of 129 mm, a width of 119 mm, and a thickness of 2 mm. The high speed surface impact total energy was measured using this test piece under a 0° C. environment according to ASTM D 3763-02 high speed impact test method.

(Impact whitening resistance)
A hard ball weighing 95.1 g and having a diameter of 28.6 mm was dropped from a height of 20 cm onto the center of the same test piece used in the measurement of the high-velocity surface impact total energy. The L value in L/a/b at the center of the test piece before and after the drop was measured, and the change in the L value after the drop from the L value before the drop was obtained as the L value change ΔL.

(Hinge part performance)
A polypropylene-based resin composition was injection-molded, and a length of 80 mm, a width of 20 mm, and a thickness of 80 mm with a hinge portion of 0.4 mm in length (3 mm including the tapered portion from the test piece), 0.2 mm in thickness, and 14 mm in width were obtained. A 2 mm test piece was produced. A test was conducted by repeating the operation of bending the test piece 90° at the hinge portion 100,000 times. The deformability, peeling resistance and whitening property of the hinge portion were evaluated according to the following criteria.

- Deformability After the test, the dimensions of the hinge portion were measured to determine the change from the original dimensions of the hinge portion, and the deformability of the hinge portion was evaluated according to the following criteria.
O: The change from the original dimensions of the hinge portion was 0.05 mm or less.
x: The change from the original dimensions of the hinge portion was greater than 0.05 mm.

• Peeling resistance After the test, the state of the hinge portion was visually observed, and the peeling resistance of the hinge portion was evaluated according to the following criteria.
◯: There was no morphological change due to peeling on the surface of the hinge portion.
x: There was a morphological change due to peeling on the surface of the hinge portion.

·Whitening property The state of the hinge portion after the test was visually observed, and the whitening property of the hinge portion was evaluated according to the following criteria.
◯: Whitening was not observed in the hinge portion.
x: Whitening was observed in the hinge portion.

Polymers used in Examples and Comparative Examples are as follows.
[Production Example 1]
(Production of propylene-based copolymer (A-1))
(1) Preparation of Solid Catalyst Component 95.2 g of anhydrous magnesium chloride, 442 ml of decane and 390.6 g of 2-ethylhexyl alcohol are heated at 130° C. for 2 hours to form a homogeneous solution, and 21 of phthalic anhydride is added to this solution. 3 g was added, and the mixture was further stirred and mixed at 130° C. for 1 hour to dissolve the phthalic anhydride.

After the homogeneous solution thus obtained was cooled to room temperature, 75 ml of this homogeneous solution was dropped into 200 ml of titanium tetrachloride maintained at -20° C. over 1 hour. After the completion of charging, the temperature of the mixed solution was raised to 110°C over 4 hours, and when the temperature reached 110°C, 5.22 g of diisobutyl phthalate (DIBP) was added, followed by stirring at the same temperature for 2 hours. held.

After completion of the reaction for 2 hours, the solid portion was collected by hot filtration, resuspended in 275 ml of titanium tetrachloride, and heated again at 110° C. for 2 hours. After completion of the reaction, the solid portion was collected again by hot filtration and thoroughly washed with 110° C. decane and hexane until no free titanium compound was detected in the solution.

Here, the detection of the free titanium compound was confirmed by the following method. 10 ml of the supernatant liquid of the solid catalyst component was collected with a syringe and charged into a 100 ml branched Schlenk tube previously purged with nitrogen. Next, the solvent hexane was dried with a stream of nitrogen, followed by vacuum drying for 30 minutes. 40 ml of ion-exchanged water and 10 ml of 50% by volume sulfuric acid were added thereto and stirred for 30 minutes. This aqueous solution was transferred to a 100 ml volumetric flask through filter paper, followed by conc. 1 ml of H ₃ PO ₄ and 5 ml of 3% H ₂ O ₂ aqueous solution as a coloring reagent for titanium were added, and the volume was made up to 100 ml with deionized water. This volumetric flask was shaken, and after 20 minutes, free titanium was detected by observing absorbance at 420 nm using UV. Free titanium was washed away and free titanium was detected until this absorption was no longer observed.

The solid titanium catalyst component (A) prepared as described above was stored as a decane slurry, part of which was dried for the purpose of investigating the catalyst composition. The composition of the solid titanium catalyst component (A) thus obtained was 2.3% by mass of titanium, 61% by mass of chlorine, 19% by mass of magnesium and 12.5% by mass of DIBP.

(2) Preparation of Prepolymerization Catalyst Components After purging a 500 ml three-necked flask equipped with a stirrer with nitrogen gas, 400 ml of dehydrated heptane, 19.2 mmol of triethylaluminum, 3.8 mmol of dicyclopentyldimethoxysilane, and the above were added. 4 g of solid titanium catalyst component (A) was added. The internal temperature was maintained at 20° C., and propylene was introduced while stirring. After 1 hour, stirring was stopped to obtain a prepolymerized catalyst component (B) in which 2 g of propylene was polymerized per 1 g of solid titanium catalyst component (A).

Polymerization [Step 1]
A 10-liter stainless steel autoclave equipped with a stirrer was thoroughly dried and purged with nitrogen, and then 6 liters of dehydrated heptane, 12.5 mmol of triethylaluminum, and 0.6 mmol of dicyclopentyldimethoxysilane were added. After replacing nitrogen in the system with propylene, hydrogen was charged at 0.80 MPa-G, and then propylene and ethylene were introduced while stirring. The amount introduced was adjusted so that the ethylene concentration in the gas phase in the polymerization tank was 0.80 mol %.

After the inside of the system stabilized at an internal temperature of 80° C. and a total pressure of 0.8 MPa-G, 20.8 ml of a heptane slurry containing 0.10 mmol of the prepolymerization catalyst component (B) in terms of Ti atoms was added, and propylene was added continuously. Polymerization was carried out at 80° C. for 3 hours while feeding to .

After a predetermined time, 50 ml of methanol was added to stop the reaction, and the temperature was lowered and the pressure was removed. The content was transferred to a filtration tank with a total filter and heated to 60° C. for solid-liquid separation. Furthermore, the solid portion was washed twice with 6 liters of heptane at 60°C. The obtained propylene/ethylene copolymer was vacuum dried to obtain a propylene-based copolymer (A-1).
Table 1 shows the content of structural units derived from ethylene and the intrinsic viscosity [η] of the obtained propylene-based copolymer (A-1).

[Production Example 2]
(Production of propylene-based copolymer (A-2))
In the production of the propylene-based copolymer (A-1), the charging amount of hydrogen in the polymerization [step 1] is 0.75 MPa-G, and the ethylene concentration in the gas phase in the polymerization tank is 0.55 mol%. A propylene copolymer (A-2) was obtained by carrying out polymerization in the same manner as in the production of the propylene copolymer (A-1), except for adjusting as follows.
Table 1 shows the content of structural units derived from ethylene and the intrinsic viscosity [η] of the obtained propylene-based copolymer (A-2).

[Production Example 3]
(Production of polymer (a-1))
In the production of the propylene-based copolymer (A-1), the charging amount of hydrogen in the polymerization [step 1] is 0.75 MPa-G, and the ethylene concentration in the gas phase in the polymerization tank is 1.45 mol%. Polymerization was carried out in the same manner as in the production of the propylene-based copolymer (A-1) except that the polymer was adjusted as above to obtain a polymer (a-1).
Table 1 shows the content of structural units derived from ethylene and the intrinsic viscosity [η] of the obtained polymer (a-1).

[Production Example 4]
(Production of polymer (a-2))
In the production of the propylene copolymer (A-1), the propylene copolymer (A Polymerization was carried out in the same manner as in the production of -1) to obtain a polymer (a-2).
Table 1 shows the content of structural units derived from ethylene and the intrinsic viscosity [η] of the obtained polymer (a-2).

[Production Example 5]
(Production of polymer (a-3))
In the production of the propylene-based copolymer (A-1), polymerization was carried out in the same manner as in the production of the propylene-based copolymer (A-1), except that ethylene was not introduced into the polymerization tank of the polymerization [step 1]. to obtain a polymer (a-3).
Table 1 shows the content of structural units derived from ethylene and the intrinsic viscosity [η] of the obtained polymer (a-3).

[Production Example 6]
(Production of propylene-based copolymer (B-1))
Polymerization [Step 2]
A 10-liter stainless steel autoclave equipped with a stirrer was thoroughly dried and purged with nitrogen, and then 6 liters of dehydrated heptane, 12.5 mmol of triethylaluminum, and 0.6 mmol of dicyclopentyldimethoxysilane were added. After replacing nitrogen in the system with propylene, 20.8 ml of a heptane slurry containing 0.10 mmol of the prepolymerization catalyst component (B) in terms of Ti atoms was added, and hydrogen was charged at 1.70 MPa-G, followed by charging. A mixed gas of propylene/ethylene: (4.0 l/min)/(2.32/min) was introduced. Propylene/ethylene copolymerization was carried out for 60 minutes at an internal temperature of 60° C. and a total pressure of 0.30 MPa-G (varying depending on the amount of introduced gas).

After a predetermined time, 50 ml of methanol was added to stop the reaction, and the temperature was lowered and the pressure was removed. The content was transferred to a filtration tank with a total filter and heated to 60° C. for solid-liquid separation. Furthermore, the solid portion was washed twice with 6 liters of heptane at 60°C. The obtained propylene/ethylene copolymer was vacuum dried to obtain a propylene-based copolymer (B-1).
Table 1 shows the content of structural units derived from ethylene and the intrinsic viscosity [η] of the obtained propylene-based copolymer (B-1).

[Production Example 7]
(Production of propylene-based copolymer (B-2))
In the production of the propylene-based copolymer (B-1), the propylene-based copolymer ( Polymerization was carried out in the same manner as in the production of B-1) to obtain a propylene-based copolymer (B-2).
Table 1 shows the content of structural units derived from ethylene and the intrinsic viscosity [η] of the obtained propylene-based copolymer (B-2).

[Production Example 8]
(Production of polymer (b-1))
In the production of the propylene-based copolymer (B-1), hydrogen was charged at 1.60 MPa-G, and a mixed gas of propylene/ethylene: (4.0 l/min)/(0.72/min) was introduced. Polymerization was carried out in the same manner as the propylene-based copolymer (B-1), except for the above, to obtain a polymer (b-1).
Table 1 shows the content of structural units derived from ethylene and the intrinsic viscosity [η] of the obtained polymer (b-1).

[Production Example 9]
(Production of polymer (b-2))
In the production of the propylene-based copolymer (B-1), hydrogen was charged at 0.20 MPa-G, and a mixed gas of propylene/ethylene: (4.0 l/min)/(2.49/min) was introduced. Polymerization was carried out in the same manner as the propylene-based copolymer (B-1), except for the above, to obtain a polymer (b-2).
Table 1 shows the content of structural units derived from ethylene and the intrinsic viscosity [η] of the obtained polymer (b-2).

Polymer (b-3): Hi-Zex 2200J manufactured by Mitsui Chemicals, Inc. (MFR: 5.2 g/10 min, density: 964 kg/m ³ )
Polymer (b-4): Evolue S P1540 manufactured by Prime Polymer Co., Ltd. (MFR: 3.8 g/10 min, density: 913 kg/m ³ )
Polymer (b-5): Evolue P SP00206 manufactured by Prime Polymer Co., Ltd. (MFR: 18.0 g/10 min, density: 900 kg/m ³ )

[Example 1]
The propylene-based copolymer (A-1), the propylene-based copolymer (B-1), and ADEKA STAB NA11 as a nucleating agent (D) were mixed in the amounts shown in Table 1, and melt-kneaded in an extruder. to prepare a polypropylene resin composition.
The melt flow rate and tensile modulus of the obtained polypropylene-based resin composition were determined by the above methods. Table 1 shows the results.
Furthermore, using the obtained polypropylene-based resin composition, the high-speed surface impact total energy, the L value change ΔL, and the performance of the hinge portion were determined by the above methods. Table 1 shows the results.

[Example 2]
The propylene-based copolymer (A-2), the propylene-based copolymer (B-2), and AL-PTBBA as the nucleating agent (D) were mixed in the amounts shown in Table 1, and melt-kneaded in an extruder. Then, a polypropylene-based resin composition was prepared.
The melt flow rate and tensile modulus of the obtained polypropylene-based resin composition were determined by the above methods. Table 1 shows the results.
Furthermore, using the obtained polypropylene-based resin composition, the high-speed surface impact total energy, the L value change ΔL, and the performance of the hinge portion were determined by the above methods. Table 1 shows the results.

[Comparative Example 1]
The propylene-based copolymer (A-1) and the propylene-based copolymer (B-1) were mixed in the amounts shown in Table 1 and melt-kneaded by an extruder to prepare a polypropylene-based resin composition.
The melt flow rate and tensile modulus of the obtained polypropylene-based resin composition were determined by the above methods. Table 1 shows the results.
Furthermore, using the obtained polypropylene-based resin composition, the high-speed surface impact total energy, the L value change ΔL, and the performance of the hinge portion were determined by the above methods. Table 1 shows the results.

[Comparative Example 2]
The propylene-based copolymer (a-1), the propylene-based copolymer (b-1), and ADEKA STAB NA21 as a nucleating agent (D) were mixed in the amounts shown in Table 1, and melt-kneaded in an extruder. to prepare a polypropylene resin composition.
The melt flow rate and tensile modulus of the obtained polypropylene-based resin composition were determined by the above methods. Table 1 shows the results.
Furthermore, using the obtained polypropylene-based resin composition, the high-speed surface impact total energy, the L value change ΔL, and the performance of the hinge portion were determined by the above methods. Table 1 shows the results.

[Comparative Example 3]
Propylene-based copolymer (a-1), polymer (b-3), and Adekastab NA11 as a nucleating agent (D) are mixed at the blending amounts shown in Table 1, and melt-kneaded in an extruder to obtain a polypropylene-based polymer. A resin composition was prepared.
The melt flow rate and tensile modulus of the obtained polypropylene-based resin composition were determined by the above methods. Table 1 shows the results.
Furthermore, using the obtained polypropylene-based resin composition, the high-speed surface impact total energy, the L value change ΔL, and the performance of the hinge portion were determined by the above methods. Table 1 shows the results.

[Comparative Example 4]
The propylene-based copolymer (a-2), the polymer (b-4), and ADEKA STAB NA21 as a nucleating agent (D) were mixed at the blending amounts shown in Table 1, and melt-kneaded in an extruder to obtain a polypropylene-based polymer. A resin composition was prepared.
The melt flow rate and tensile modulus of the obtained polypropylene-based resin composition were determined by the above methods. Table 1 shows the results.
Furthermore, using the obtained polypropylene-based resin composition, the high-speed surface impact total energy, the L value change ΔL, and the performance of the hinge portion were determined by the above methods. Table 1 shows the results.

[Comparative Example 5]
The propylene-based copolymer (a-3), the propylene-based copolymer (b-2), and AL-PTBBA as a nucleating agent (D) were mixed in the amounts shown in Table 1, and melt-kneaded in an extruder. Then, a polypropylene-based resin composition was prepared.
The melt flow rate and tensile modulus of the obtained polypropylene-based resin composition were determined by the above methods. Table 1 shows the results.
Furthermore, using the obtained polypropylene-based resin composition, the high-speed surface impact total energy, the L value change ΔL, and the performance of the hinge portion were determined by the above methods. Table 1 shows the results.

[Comparative Example 6]
The propylene-based copolymer (a-2), the polymer (b-5), and ADEKA STAB NA21 as a nucleating agent (D) were mixed at the blending amounts shown in Table 1, and melt-kneaded in an extruder to obtain a polypropylene-based polymer. A resin composition was prepared.
The melt flow rate and tensile modulus of the obtained polypropylene-based resin composition were determined by the above methods. Table 1 shows the results.
Furthermore, using the obtained polypropylene-based resin composition, the high-speed surface impact total energy, the L value change ΔL, and the performance of the hinge portion were determined by the above methods. Table 1 shows the results.

[Comparative Example 7]
The propylene-based copolymer (a-2) and Adekastab NA21 as a nucleating agent (D) were mixed in the amounts shown in Table 1 and melt-kneaded in an extruder to prepare a polypropylene-based resin composition.

The melt flow rate and tensile modulus of the obtained polypropylene-based resin composition were determined by the above methods. Table 1 shows the results.
Furthermore, using the obtained polypropylene-based resin composition, the high-speed surface impact total energy, the L value change ΔL, and the performance of the hinge portion were determined by the above methods. Table 1 shows the results.

Claims (3)

80 to 90 parts by mass of a propylene copolymer (A) satisfying the following requirements (A1) and (A2), 10 to 20 parts by mass of a propylene copolymer (B) satisfying the following requirements (B1) and (B2), and 0.01 to 0.6 parts by mass of a nucleating agent (D) (provided that the total of the propylene-based copolymer (A) and the propylene-based copolymer (B) is 100 parts by mass), and the following requirements A polypropylene-based resin composition that satisfies (C1).
(A1) The content of structural units derived from ethylene in the propylene-based copolymer (A) is 1.0 to 3.0% by mass.
(A2) The intrinsic viscosity [η] _(A) of the propylene-based copolymer (A) in decalin at 135°C is 1.0 to 2.0 dl/g.
(B1) The content of structural units derived from ethylene in the propylene-based copolymer (B) is 20 to 40% by mass.
(B2) The intrinsic viscosity [η] _(B) of the propylene copolymer (B) in decalin at 135°C is 1.0 to 2.0 dl/g, and the propylene copolymer (B)/propylene copolymer The intrinsic viscosity ratio [η] _(B) /[η] _(A ) of the polymer (A) is from 0.8 to 1.4.
(C1) A melt flow rate (MFR) of 10 to 50 g/10 minutes measured at 230° C. under a load of 2.16 kg according to JIS K 7210. The polypropylene-based resin composition according to claim 1, further satisfying the following requirements (C2) to (C4).
(C2) It has a tensile modulus of elasticity of 800 to 900 MPa as measured according to JIS K 7161.
(C3) High-speed surface impact total energy measured at 0° C. in accordance with ASTM D 3763-02 high-speed impact test method is 20 J or more.
(C4) The change in L value ΔL in L/a/b at the center of the test piece measured before and after dropping a rigid ball onto the center of the test piece obtained by injection molding is 10 or less. A molded article comprising the polypropylene-based resin composition according to claim 1 or 2.