JP2017052906A - Polypropylene resin composition for inflation film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polypropylene resin composition providing an inflation film having stable film production property in an inflation molding and less in thickness deviation and fish eye.SOLUTION: There is provided a polypropylene resin composition where a propylene-ethylene copolymer is dispersed in a propylene single polymer, having mass of the ethylene-propylene copolymer in the composition of 15 to 35 wt.%, propylene content in the copolymer of 70 to 85 wt.%, intrinsic viscosity (XSIV) of a xylene soluble component at 25°C of the composition of 2 to 4 dl/g, melt flow rate at 230°C and load of 21.18 N of the composition of 0.1 to 10 g/10 min., Mw/Mn of the xylene soluble component of the composition of 7 to 12 and stain hardening exponent of the composition of over 1 and less than 10.SELECTED DRAWING: None

Description

  The present invention relates to a polypropylene resin composition for an inflation film. Specifically, the present invention relates to a polypropylene resin composition for an inflation film suitable as a sealant raw material for a retort film.

  Polypropylene, which is inexpensive and has excellent rigidity, moisture resistance, and heat resistance, is widely used in various industrial fields. In particular, the polypropylene resin composition has excellent appearance, mechanical properties, packaging suitability, etc., so it produces molded products, especially sheets and film-like molded products for packaging applications such as food packaging and fiber packaging represented by retort film. It is used to do.

Patent Document 1 discloses an ethylene-propylene copolymer polymerized using a Ziegler-Natta type catalyst, and also discloses a film formed by melt extrusion film formation.
Patent Document 2 discloses a composition containing polypropylene, propylene, and a copolymer elastomer of ethylene or an α-olefin having 4 to 12 carbon atoms, and a film using the composition is resistant to low temperatures. It is disclosed that the balance between impact properties and rigidity is good, the transparency is excellent, and the heat seal strength is also excellent.
Patent Document 3 discloses a polypropylene resin molded article having propylene and ethylene or an α-olefin copolymer block having 4 to 12 carbon atoms and having a b-axis orientation by a wide angle X-ray diffraction method.

  In the techniques described in these patent documents, a Ziegler-Natta type solid catalyst system (phthalate catalyst) containing diisobutyl phthalate as an internal electron donor compound is used when the copolymer is polymerized. The copolymer polymerized using the phthalate catalyst has a problem that the molecular weight distribution is slightly narrow and the dispersibility in the copolymer is inferior. For this reason, none of the above-cited copolymers can completely solve the problem of fisheye generation.

Patent Document 4 discloses a solid titanium catalyst component for olefin polymerization using a cyclic ester compound as an internal electron donor compound.
Patent Document 5 discloses a solid titanium catalyst component for olefin polymerization using a compound having an ester structure or a diester structure as an internal electron donor compound.
Patent Document 6 discloses an α-olefin polymerization catalyst component using a diester compound having a hetero atom selected from Group 15 as an internal electron donor compound.
Patent Document 7 discloses an α-olefin polymerization catalyst component using a diester compound having a hetero atom selected from Group 16 as an internal electron donor compound.
Patent Document 8 discloses a component for olefin polymerization using succinate (succinate) as an internal electron donor compound.

  Patent Documents 4 to 8 disclose solid catalyst systems containing various succinate compounds (compounds having a succinate structure), and resin compositions having specific properties suitable for inflation films using the same. There is no mention of making things.

JP-A-6-93062 JP 2004-27217 A JP-A-9-316283 International Publication No. 2009/069483 International Publication No. 2009/057747 JP-A-2005-306910 JP 2004-131537 A Special table 2002-542347

  The inventors have found that with the resin composition described in the above-mentioned patent document, it is difficult to obtain a stable film-forming property in inflation molding and an inflation film with less uneven thickness and fish eyes. In view of the above, it is an object of the present invention to provide a polypropylene resin composition that provides an inflation film having a stable film forming property and less uneven thickness in inflation molding.

The inventors have found that the above problem can be solved by a polypropylene resin composition having a specific composition, a polydispersity in a specific range, a strain hardening index, and the like. That is, the said subject is solved by the following this invention.
[1] A polypropylene resin composition in which a propylene-ethylene copolymer is dispersed in a propylene homopolymer,
The amount of the ethylene-propylene copolymer in the composition is 15 to 35% by weight;
The propylene content in the copolymer is 70 to 85% by weight,
The intrinsic viscosity (XSIV) of xylene solubles at 25 ° C. of the composition is 2 to 4 dl / g,
Mw / Mn of xylene insoluble matter at 25 ° C. of the composition is 7 to 12, and the melt flow rate at 230 ° C. and a load of 21.18 N of the composition is 0.1 to 10 g / 10 min.
The strain hardening index of the composition is greater than 1 and less than 10;
Polypropylene resin composition.
[2] The resin composition according to [1], wherein the strain hardening index is more than 1 and 5 or less.
[3] (A) A solid catalyst containing, as an essential component, an electron donor compound selected from magnesium, titanium, halogen, and a succinate compound;
(B) Organoaluminum compound; and (C) The resin composition according to [1], obtained by polymerizing propylene and ethylene using a catalyst containing an external electron donor compound selected from silicon compounds.
[4] An inflation film manufactured using the resin composition according to any one of [1] to [3].
[5] A retort sealant film including the inflation film described in [4] in at least one layer.
[6] (A) A solid catalyst containing, as an essential component, an electron donor compound selected from magnesium, titanium, halogen, and a succinate compound;
(B) an organoaluminum compound; and (C) a step of polymerizing propylene and ethylene using a catalyst containing an external electron donor compound selected from silicon compounds. Manufacturing method.
[7] A method for producing a film, comprising a step of producing the resin composition by the method according to [6], and a step of inflation molding the resin composition.

  According to the present invention, it is possible to provide a polypropylene resin composition that can provide a stable film-forming property in inflation molding and an inflation film with less uneven thickness and fish eyes.

It is a figure explaining how to obtain a strain hardening index.

  The present invention is described in detail below. In the present invention, “to” includes values at both ends thereof. That is, “X to Y” includes both X and Y. “X or Y” includes either one or both of X and Y.

1. Polypropylene resin composition (1) Propylene homopolymer and ethylene-propylene copolymer In the resin composition of the present invention, a propylene-ethylene copolymer (hereinafter also referred to as “BIPO”) is dispersed in a propylene homopolymer. ing. The homopolymer of the present invention includes a copolymer with a trace amount (less than 0.3% by weight) of an α-olefin which may be mixed due to the characteristics of the production process of the polymer. The amount of BIPO is 15 to 35% by weight, preferably 17 to 34% by weight. If the amount of BIPO is less than 15% by weight, the impact strength decreases, and if it exceeds 35% by weight, the amount of eluted components increases, which is not preferable for retort use.

  The propylene content in BIPO is 70 to 85% by weight, preferably 73 to 82% by weight, based on the weight of BIPO. When the propylene content in BIPO is less than 70% by weight, the fish eye increases when the film is formed, and the impact strength may also decrease. Further, since the compatibility with the propylene homopolymer becomes insufficient, the strain hardening index necessary for the present invention cannot be obtained even with a relatively broad molecular weight distribution of the resin composition of the present invention. On the other hand, if the propylene content exceeds 85% by weight, the stickiness of the film becomes strong.

(2) XSIV
The intrinsic viscosity (XSIV) of the xylene-soluble component at 25 ° C. of the resin composition of the present invention is 2 to 4 dl / g, preferably 2.1 to 3.3 dl / g. The xylene-soluble component is a component having no crystallinity, and XSIV is an index of the molecular weight of the component. The main component of xylene solubles is derived from BIPO. XSIV in the composition is obtained by obtaining a component soluble in xylene at 25 ° C. and measuring the intrinsic viscosity of the component by a conventional method. It is known that there is a strong correlation between the intrinsic viscosity (XSIV) of the xylene solubles of the polypropylene resin composition and the heat seal strength of the film, and the greater the value of XSIV, the greater the heat seal strength of the film. improves. On the other hand, if XSIV is too large, fish eyes will increase. From the above, the film obtained from the resin composition of the present invention having the above range of XSIV is excellent in the balance between heat sealability and low fish eye.

(3) Melt Flow Rate The melt flow rate (hereinafter also referred to as “MFR”) at 230 ° C. and a load of 21.18 N of the resin composition of the present invention is 0.1 to 10 g / 10 minutes, preferably 1.0 to 4.0 g / 10 min. If the MFR is less than 0.1 (g / 10 min), the resin pressure in the film molding machine will increase and the productivity will decrease, and the smoothness of the film surface will decrease and the film quality will deteriorate. Can occur. When the MFR exceeds 10 (g / 10 minutes), the strength of the film, particularly the impact strength, may be significantly reduced.

(4) Molecular weight distribution The molecular weight distribution (Mw / Mn) of the resin composition of the present invention is relatively wide. The molecular weight distribution of the resin composition of the present invention is evaluated by the xylene insoluble content at 25 ° C., and the value is 7 to 12, preferably 7.5 to 11. The molecular weight distribution can be obtained by measuring the weight average molecular weight Mw and the number average molecular weight Mn by gel permeation chromatography. The main component of the xylene insoluble matter is derived from the propylene homopolymer, but the large Mw / Mn of the xylene insoluble matter is expected to have a wide molecular weight distribution in the copolymer (BIPO) portion, It is considered that the dispersibility with the polymer (BIPO) is improved. A broad molecular weight distribution means that both the propylene homopolymer portion and the copolymer (BIPO) portion have a relatively large number of high molecular weight molecules. Due to this high molecular weight component, the resin composition of the present invention has a somewhat high strain hardening index when stretched. As a result, the resin composition in a molten state is uniformly stretched, and a film with less uneven thickness can be obtained when inflation molding is performed. On the other hand, a broad molecular weight distribution means that there are relatively many low molecular weight molecules. Since the fluidity is improved by this low molecular weight component, the extrusion load during melting can be reduced.

(5) Strain hardening index A strain hardening index is calculated | required by measuring the extension viscosity which is a viscosity under the extension deformation of molten resin. The strain hardening index of the resin composition of the present invention is more than 1 and less than 10, preferably more than 1 and 5 or less. When the strain hardening index is within this range, the melted resin composition is easily stretched uniformly, and the knitted meat of the resulting film can be reduced. In the present invention, the strain hardening index is calculated from the extensional viscosity measured using an extensional viscometer under the conditions of measurement temperature: 200 ° C. and shear rate: 0.1 s ⁻¹ as follows.

1) The logarithm of elongational viscosity (Pa · sec) is plotted on the vertical axis, and the logarithm of elongation time (seconds) is plotted on the horizontal axis. The value of elongational viscosity at 40 seconds (hereinafter referred to as “strain 4”) (1).
2) A curve in a range from 10 seconds (hereinafter referred to as “strain 1”) before strain hardening starts is approximated by a straight line having the smallest slope. The value of the extension viscosity when the straight line is extrapolated to strain 4 is defined as (2).
3) Let the value represented by (1) / (2) be the strain hardening index.

(6) Additive, etc. In addition, the resin composition of the present invention comprises conventional additives (nucleating agents, antioxidants, hydrochloric acid absorbents, heat stabilizers, which are usually used in oil-extended and other olefin polymers. , Light stabilizers, ultraviolet absorbers, internal lubricants, external lubricants, antistatic agents, flame retardants, dispersants, copper damage inhibitors, neutralizers, plasticizers, foaming agents, anti-bubble agents, crosslinking agents, peroxides ) And pigments (organic or inorganic).

2. Production Method of Resin Composition of the Present Invention The resin composition of the present invention is not limited even if it is a resin composition produced as long as the above properties are satisfied. However, a resin composition obtained by polymerizing propylene and ethylene using a succinate catalyst is preferred.

(1) Succinate-based catalyst A succinate-based catalyst is a catalyst containing a succinate-based compound as an electron donor compound. In the present invention, (A) a solid catalyst containing an electron donor compound selected from magnesium, titanium, halogen and succinate compounds as an essential component, (B) an organoaluminum compound, and (C) a silicon compound are selected. A catalyst comprising an external electron donor compound is preferred. When a succinate-based catalyst is used, a resin composition having a wide molecular weight distribution can be obtained. The resin composition polymerized using the catalyst has a higher strain hardening index and superior to a resin composition having the same molecular weight distribution obtained by pelletizing or powder blending a polymer polymerized using another catalyst. Shows fluidity. This is because the resin composition produced using a succinate-based catalyst has a high molecular weight component and a low molecular weight component integrated in a state close to the molecular level, but the latter resin composition is mixed in a state close to the molecular level. This is probably because the molecular weight distribution is merely the same. However, it is not realistic to express this in words in the claims.

1) Component (A)
Component (A) can be prepared by a known method, for example, by bringing a magnesium compound, a titanium compound and an electron donor compound into contact with each other. As a titanium compound used for preparation of a component (A), the tetravalent titanium compound represented by general formula: Ti (OR) _{gX4 -g} is suitable. In the formula, R is a hydrocarbon group, X is a halogen, and 0 ≦ g ≦ 4. As titanium compounds, TiCl ₄ and more specifically, TiBr _4, titanium tetrahalides such as _{TiI 4; Ti (OCH 3)} Cl 3, Ti (OC 2 H 5) Cl 3, Ti (O n -C 4 H _{9) Cl 3, Ti (OC} 2 H 5) Br 3, Ti (OisoC 4 H 9) trihalide, alkoxy titanium such as _{Br 3; Ti (OCH 3)} 2 Cl 2, Ti (OC 2 H 5) 2 Cl ₂ , Di (halogenated alkoxytitanium) such as Ti (O _n —C ₄ H ₉ ) ₂ Cl ₂ , Ti (OC ₂ H ₅ ) ₂ Br ₂ ; 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 monohalogenated trialkoxy titanium such as _{Br; Ti (OCH 3) 4} , Ti (OC 2 H 5) _{4, Ti (O n -C 4} H 9) 4 and the like tetraalkoxytitanium such. Among these, preferred are halogen-containing titanium compounds, particularly titanium tetrahalides, and more particularly preferred is titanium tetrachloride.

  Magnesium compounds used for the preparation of component (A) include magnesium compounds having a magnesium-carbon bond or magnesium-hydrogen bond, such as dimethylmagnesium, diethylmagnesium, dipropylmagnesium, dibutylmagnesium, diamylmagnesium, dihexylmagnesium, Examples include decylmagnesium, ethylmagnesium chloride, propylmagnesium chloride, butylmagnesium chloride, hexylmagnesium chloride, amylmagnesium chloride, butylethoxymagnesium, ethylbutylmagnesium, butylmagnesium hydride and the like. These magnesium compounds can also be used, for example, in the form of a complex compound with organic aluminum or the like, and may be liquid or solid. Further preferred magnesium compounds include magnesium halides such as magnesium chloride, magnesium bromide, magnesium iodide, magnesium fluoride; methoxy magnesium chloride, ethoxy magnesium chloride, isopropoxy magnesium chloride, butoxy magnesium chloride, octoxy magnesium chloride, and the like. Alkoxymagnesium halides; aryloxymagnesium halides such as phenoxymagnesium chloride and methylphenoxymagnesium chloride; alkoxymagnesiums such as ethoxymagnesium, isopropoxymagnesium, butoxymagnesium, n-octoxymagnesium and 2-ethylhexoxymagnesium; phenoxy Allyloxy Magnesium like Magnesium, Dimethylphenoxy Magnesium ; Magnesium laurate, such as carboxylic acid salts of magnesium such as magnesium stearate and the like.

  The electron donor compound used for the preparation of component (A) is generally referred to as “internal electron donor”. In this catalyst, a succinate compound is used as the electron donor compound. The succinate compound means a diester of succinic acid or a substituted succinic acid. Hereinafter, the succinate compound will be described in detail. The succinate compound preferably used in the present invention is represented by the following formula (I).

In which the radicals R ₁ and R ₂ are identical or different from one another and optionally contain heteroatoms, C ₁ -C ₂₀ linear or branched alkyl, alkenyl, cycloalkyl, aryl, arylalkyl or alkyl An aryl group; the groups R _{3 to} R ₆ are the same or different from each other and are hydrogen, or optionally a heteroatom, C ₁ -C ₂₀ linear or branched alkyl, alkenyl, cycloalkyl, aryl, The groups R _{3 to} R ₆ which are arylalkyl or alkylaryl groups and are bonded to the same carbon atom or different carbon atoms may be bonded together to form a ring.

R ₁ and R ₂ are preferably C ₁ -C ₈ alkyl, cycloalkyl, aryl, arylalkyl, and alkylaryl groups. Particularly preferred are compounds wherein R ₁ and R ₂ are selected from primary alkyls, especially branched primary alkyls. Examples of suitable R ₁ and R ₂ groups are C ₁ -C ₈ alkyl groups such as methyl, ethyl, n-propyl, n-butyl, isobutyl, neopentyl, 2-ethylhexyl. Ethyl, isobutyl, and neopentyl are particularly preferred.

One preferred group of compounds represented by formula (I) are branched alkyl, cycloalkyl, aryl, arylalkyl, wherein R _{3 to} R ₅ are hydrogen and R ₆ has 3 to 10 carbon atoms. And an alkylaryl group. Preferred specific examples of such mono-substituted succinate compounds include diethyl-sec-butyl succinate, diethyl hexyl succinate, diethyl cyclopropyl succinate, diethyl norbornyl succinate, diethyl perihydrosuccinate, diethyl Trimethylsilyl succinate, diethyl methoxy succinate, diethyl-p-methoxyphenyl succinate, diethyl-p-chlorophenyl succinate, diethyl phenyl succinate, diethyl cyclohexyl succinate, diethyl benzyl succinate, diethyl cyclohexyl Methyl succinate, diethyl-t-butyl succinate, diethyl isobutyl succinate, diethyl isopropyl succinate, diethyl neopentyl succinate, diethyl isopenty Succinate, diethyl (1-trifluoromethylethyl) succinate, diethyl fluorenyl succinate, 1-ethoxycarbodiisobutylphenyl succinate, diisobutyl-sec-butyl succinate, diisobutyl hexyl succinate, diisobutylcyclopropyl succinate , Diisobutyl norbornyl succinate, diisobutyl perhydrosuccinate, diisobutyltrimethylsilyl succinate, diisobutyl methoxy succinate, diisobutyl-p-methoxyphenyl succinate, diisobutyl-p-chlorophenyl succinate, diisobutyl cyclohexyls Succinate, diisobutylbenzyl succinate, diisobutylcyclohexylmethyl succinate, diisobutyl-t-butyl succinate Diisobutyl isobutyl succinate, diisobutyl isopropyl succinate, diisobutyl neopentyl succinate, diisobutyl isopentyl succinate, diisobutyl (1-trifluoromethylethyl) succinate, diisobutyl fluorenyl succinate, dineopentyl-sec- Butyl succinate, dineopentyl texyl succinate, dineopentyl cyclopropyl succinate, dineopentyl norbornyl succinate, dineopentyl perhydrosuccinate, dineopentyl trimethylsilyl succinate, dineo Pentylmethoxy succinate, dineopentyl-p-methoxyphenyl succinate, dineopentyl-p-chlorophenyl succinate, dineopentylphenyl succinate, dinene Opentyl cyclohexyl succinate, dineopentyl benzyl succinate, dineopentyl cyclohexyl methyl succinate, dineopentyl-t-butyl succinate, dineopentyl isobutyl succinate, dineopentyl isopropyl succinate, di Neopentyl neopentyl succinate, dineopentyl isopentyl succinate, dineopentyl (1-trifluoromethylethyl) succinate, dineopentyl fluorenyl succinate.

Another preferred group of compounds within the scope of formula (I) are C ₁ -C ₂₀ linear, wherein at least two groups from R _{3 to} R ₆ are different from hydrogen and optionally contain heteroatoms. Or a branched alkyl, alkenyl, cycloalkyl, aryl, arylalkyl, or alkylaryl group. Particularly preferred are compounds in which two groups different from hydrogen are bonded to the same carbon atom. Specifically, R ₃ and R ₄ are different from hydrogen, and R ₅ and R ₆ are hydrogen atoms. Preferred specific examples of such 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-methylsuccinate, diethyl-2-tetradecyl-2-ethylsuccinate, diethyl-2-isobutyl-2-ethylsuccinate, diethyl-2- (1-trifluoro Methylethyl) -2-methylsuccinate, diethyl-2-isopentyl-2- Sobutyl succinate, diethyl-2-phenyl-2-n-butyl succinate, diisobutyl-2,2-dimethyl succinate, diisobutyl-2-ethyl-2-methyl succinate, diisobutyl-2-benzyl- 2-isopropyl succinate, 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-isopropyl-2-methyl succinate, diisobutyl-2-tetradecyl-2-ethyl succinate, diisobutyl-2-isobutyl-2-ethyl succinate, diisobutyl -2- (1-trifluoro Tilethyl) -2-methylsuccinate, diisobutyl-2-isopentyl-2-isobutylsuccinate, diisobutyl-2-phenyl-2-n-butylsuccinate, dineopentyl-2,2-dimethylsuccinate, dineopentyl 2-ethyl-2-methyl succinate, dineopentyl-2-benzyl-2-isopropyl succinate, dineopentyl-2-cyclohexylmethyl-2-isobutyl succinate, dineopentyl-2-cyclopentyl-2-n-butyl Succinate, dineopentyl-2,2-diisobutyl succinate, dineopentyl-2-cyclohexyl-2-ethyl succinate, dineopentyl-2-isopropyl-2-methyl succinate, dineopentyl-2-tetradecyl-2-ethyl succinate , Dineopentyl-2-isobutyl-2-ethyl succinate, dineopentyl-2- (1-trifluoromethylethyl) -2-methyl succinate, dineopentyl-2-isopentyl-2-isobutyl succinate, dineopentyl 2-Phenyl-2-n-butyl succinate.

Furthermore, compounds in which at least two groups different from hydrogen are bonded to different carbon atoms are particularly preferred. Specifically, it is a compound in which R ₃ and R ₅ are groups different from hydrogen. In this case, R ₄ and R ₆ may be a hydrogen atom or a group different from hydrogen, but it is preferable that either one is a hydrogen atom (trisubstituted succinate). Preferred examples of such compounds are diethyl-2,3-bis (trimethylsilyl) succinate, diethyl-2,2-sec-butyl-3-methylsuccinate, diethyl-2- (3,3,3- Trifluoropropyl) -3-methylsuccinate, diethyl-2,3-bis (2-ethylbutyl) succinate, diethyl-2,3-diethyl-2-isopropylsuccinate, diethyl-2,3-diisopropyl-2 -Methyl succinate, diethyl-2,3-dicyclohexyl-2-methyldiethyl-2,3-dibenzyl succinate, diethyl-2,3-diisopropyl succinate, diethyl-2,3-bis (cyclohexylmethyl) ) Succinate, diethyl-2,3-di-t-butylsuccinate, diethyl-2,3-diisobuty Succinate, diethyl-2,3-dineopentyl succinate, diethyl-2,3-diisopentyl succinate, diethyl-2,3- (1-trifluoromethylethyl) succinate, diethyl-2,3- Tetradecyl succinate, diethyl-2,3-fluorenyl succinate, diethyl-2-isopropyl-3-isobutyl succinate, diethyl-2-tert-butyl-3-isopropyl succinate, diethyl-2- Isopropyl-3-cyclohexyl succinate, diethyl-2-isopentyl-3-cyclohexyl succinate, diethyl-2-tetradecyl-3-cyclohexylmethyl succinate, diethyl-2-cyclohexyl-3-cyclopentyl succinate, diisobutyl -2,3-diethyl-2-iso Lopyl succinate, diisobutyl-2,3-diisopropyl-2-methyl succinate, 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-t-butyl succinate, diisobutyl-2,3-diisobutyl succinate, diisobutyl-2 , 3-Dineopentyl succinate, diisobutyl-2,3-diisopentyl succinate, diisobutyl-2,3- (1-trifluoromethylethyl) succinate, diisobutyl-2,3-tetradecyl succinate Diisobutyl-2,3-fluorenylsuccinate Diisobutyl-2-isopropyl-3-isobutyl succinate, diisobutyl-2-tert-butyl-3-isopropyl succinate, diisobutyl-2-isopropyl-3-cyclohexyl succinate, diisobutyl-2-isopentyl-3- Cyclohexyl succinate, diisobutyl-2-tetradecyl-3-cyclohexylmethyl succinate, diisobutyl-2-cyclohexyl-3-cyclopentyl succinate, dineopentyl-2,3-bis (trimethylsilyl) succinate, dineopentyl-2,2- sec-butyl-3-methyl succinate, dineopentyl-2- (3,3,3-trifluoropropyl) -3-methyl succinate, dineopentyl-2,3-bis (2-ethylbutyl) succinate, cine Pentyl-2,3-diethyl-2-isopropyl succinate, dineopentyl-2,3-diisopropyl-2-methyl succinate, dineopentyl-2,3-dicyclohexyl-2-methyl succinate, dineopentyl-2,3 -Dibenzyl succinate, dineopentyl-2,3-diisopropyl succinate, dineopentyl-2,3-bis (cyclohexylmethyl) succinate, dineopentyl-2,3-di-t-butyl succinate, dineopentyl-2, 3-diisobutyl succinate, dineopentyl-2,3-dineopentyl succinate, dineopentyl-2,3-diisopentyl succinate, dineopentyl-2,3- (1-trifluoromethylethyl) succinate, dineopentyl -2,3-tetradeci Succinate, dineopentyl-2,3-fluorenyl succinate, dineopentyl-2-isopropyl-3-isobutyl succinate, dineopentyl-2-tert-butyl-3-isopropyl succinate, dineopentyl-2-isopropyl-3- They are cyclohexyl succinate, dineopentyl-2-isopentyl-3-cyclohexyl succinate, dineopentyl-2-tetradecyl-3-cyclohexylmethyl succinate, and dineopentyl-2-cyclohexyl-3-cyclopentyl succinate.

Among the compounds of the formula (I), compounds in which some of the groups R _{3 to} R ₆ are bonded together to form a ring can also be preferably used. As such compounds, compounds listed in JP-T-2002-542347, for example, 1- (ethoxycarbonyl) -1- (ethoxyacetyl) -2,6-dimethylcyclohexane, 1- (ethoxycarbonyl) -1- ( Ethoxyacetyl) -2,5-monodimethylcyclopentane, 1- (ethoxycarbonyl) -1- (ethoxyacetylmethyl) -2 monomethylcyclohexane, 1- (ethoxycarbonyl) -1- (ethoxy (cyclohexyl) acetyl) cyclohexane Can be mentioned. In addition, a cyclic succinate compound as disclosed in, for example, International Publication No. 2009/069483 can also be suitably used. As another example of the cyclic succinate compound, a compound disclosed in International Publication No. 2009/057747 is also preferable.

Of the compounds of formula (I), when the groups R _{3 to} R ₆ contain heteroatoms, the heteroatoms may be group 15 atoms including nitrogen and phosphorus atoms or group 16 atoms including oxygen and sulfur atoms. preferable. Examples of the compound in which the groups R _{3 to} R ₆ include a Group 15 atom include compounds disclosed in JP-A-2005-306910. On the other hand, examples of the compound in which the groups R _{3 to} R ₆ include a Group 16 atom include compounds disclosed in JP-A No. 2004-131537.

2) Organoaluminum compound (component B)
The following are mentioned as an organoaluminum compound of a component (B).
Trialkylaluminum such as triethylaluminum, tributylaluminum;
Trialkenyl aluminum such as triisoprenyl aluminum:
Dialkylaluminum alkoxides such as diethylaluminum ethoxide and dibutylaluminum butoxide;
Alkylaluminum sesquialkoxides such as ethylaluminum sesquiethoxide and butylaluminum sesquibutoxide;

Partially halogenated alkylaluminums such as alkylaluminum dihalogenides such as ethylaluminum dichloride, propylaluminum dichloride, butylaluminum dibromide and the like;
Dialkylaluminum hydrides such as diethylaluminum hydride, dibutylaluminum hydride;
Partially hydrogenated alkylaluminums such as alkylaluminum dihydrides such as ethylaluminum dihydride, propylaluminum dihydride;
Partially alkoxylated and halogenated alkylaluminums such as ethylaluminum ethoxychloride, butylaluminum butoxychloride, ethylaluminum ethoxybromide.

3) Electron donor compound (component C)
The electron donor compound of component (C) is generally referred to as an “external electron donor”. In this catalyst, an organosilicon compound is preferable. The following is mentioned as a preferable organosilicon compound.

  Trimethylmethoxysilane, trimethylethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diisopropyldimethoxysilane, t-butylmethyldimethoxysilane, t-butylmethyldiethoxysilane, t-amylmethyldiethoxysilane, diphenyldimethoxysilane, phenylmethyl Dimethoxysilane, diphenyldiethoxysilane, bis o-tolyldimethoxysilane, bism-tolyldimethoxysilane, bisp-tolyldimethoxysilane, bisp-tolyldiethoxysilane, bisethylphenyldimethoxysilane, dicyclopentyldimethoxysilane, dicyclohexyldimethoxy Silane, cyclohexylmethyldimethoxysilane, cyclohexylmethyldiethoxysilane, ethyltrimethoxysilane, ethyl Riethoxysilane, vinyltrimethoxysilane, methyltrimethoxysilane, n-propyltriethoxysilane, decyltrimethoxysilane, decyltriethoxysilane, phenyltrimethoxysilane, γ-chloropropyltrimethoxysilane, methyltriethoxysilane, ethyl Triethoxysilane, vinyltriethoxysilane, t-butyltriethoxysilane, texyltrimethoxysilane, n-butyltriethoxysilane, iso-butyltriethoxysilane, phenyltriethoxysilane, γ-aminopropyltriethoxysilane, chloro Triethoxysilane, ethyltriisopropoxysilane, vinyltributoxysilane, cyclohexyltrimethoxysilane, cyclohexyltriethoxysilane, 2-norbornanetrimethoxy Lan, 2-norbornanetriethoxysilane, 2-norbornanemethyldimethoxysilane, ethyl silicate, butyl silicate, trimethylphenoxysilane, methyltriallyloxysilane, vinyltris (β-methoxyethoxysilane), vinyltriacetoxysilane, Dimethyltetraethoxydisiloxane.

  Among them, ethyltriethoxysilane, n-propyltriethoxysilane, n-propyltrimethoxysilane, t-butyltriethoxysilane, t-butylmethyldimethoxysilane, t-butylmethyldiethoxysilane, t-butylethyldimethoxysilane, t-butylpropyldimethoxysilane, t-butylt-butoxydimethoxysilane, t-butyltrimethoxysilane, i-butyltrimethoxysilane, isobutylmethyldimethoxysilane, i-butylsec-butyldimethoxysilane, ethyl (perhydroisoquinoline 2- Yl) dimethoxysilane, bis (decahydroisoquinolin-2-yl) dimethoxysilane, tri (isopropenyloxy) phenylsilane, texyltrimethoxysilane, vinyltriethoxysilane, phenyltrie Xysilane, phenyltrimethoxysilane, vinyltributoxysilane, diphenyldimethoxysilane, diisopropyldimethoxysilane, diisobutyldimethoxysilane, i-butyli-propyldimethoxysilane, cyclopentyl t-butoxydimethoxysilane, dicyclopentyldimethoxysilane, cyclohexylmethyldimethoxysilane, Cyclohexyl i-butyldimethoxysilane, cyclopentyl i-butyldimethoxysilane, cyclopentylisopropyldimethoxysilane, di-sec-butyldimethoxysilane, diethylaminotriethoxysilane, tetraethoxysilane, tetramethoxysilane, isobutyltriethoxysilane, phenylmethyldimethoxysilane, Phenyltriethoxylane, bis p-tolyldimethoxy Silane, p-tolylmethyldimethoxysilane, dicyclohexyldimethoxysilane, cyclohexylethyldimethoxysilane, 2-norbornanetriethoxysilane, 2-norbornanemethyldimethoxysilane, diphenyldiethoxysilane, methyl (3,3,3-trifluoropropyl) dimethoxy Silane and ethyl silicate are preferred.

(2) Polymerization It is preferable to polymerize the raw material monomers using two or more reactors. The polymerization may be carried out in liquid phase, gas phase or liquid-gas phase. The polymerization pressure is preferably in the range of 33 to 45 bar when carried out in the liquid phase and in the range of 5 to 30 bar when carried out in the gas phase. Conventional molecular weight regulators known in the art such as chain transfer agents (eg, hydrogen or ZnEt ₂ ) may be used.

  Further, a polymerization vessel having a gradient of monomer concentration and polymerization conditions may be used. In such a polymerization vessel, for example, a monomer in which at least two polymerization regions are connected can be used, and the monomer can be polymerized by gas phase polymerization. Specifically, in the presence of a catalyst, a monomer is supplied and polymerized in a polymerization region including a riser, and a monomer is supplied and polymerized in a downcomer connected to the riser. The polymer product is recovered while circulating. This method comprises means for completely or partially preventing the gas mixture present in the riser from entering the downcomer. Also, a gas or liquid mixture having a composition different from the gas mixture present in the riser is introduced into the downcomer. As the above polymerization method, for example, a method described in JP-T-2002-520426 can be applied.

3. Film The resin composition of the present invention is suitable for film production, particularly for film production by inflation molding. Inflation molding can be performed according to a conventional method. For example, it can be carried out at a temperature such as a cylinder temperature of 200 to 250 ° C. and a die temperature of 240 to 280 ° C. using an inflation molding machine. The blow ratio may be 2 to 3, the film width (folded diameter when the tube is crushed) is 300 to 500 mm, and the molding speed is about 10 to 50 m / min.

  As described above, the film obtained from the resin composition of the present invention has less fish eyes and less uneven thickness. The degree of uneven thickness can be evaluated by measuring a film (thickness: 60 μm) having a length of 700 mm (corresponding to the width when the tube is opened) with a continuous thickness gauge at intervals of 5 mm, and evaluating the difference between the maximum value and the minimum value. . In the present invention, the difference is preferably 11 μm or less, and more preferably 10 μm or less.

The following examples further illustrate the present invention. Each analysis was performed as follows.
[MFR]
According to JIS K 7210, the measurement was performed under conditions of a temperature of 230 ° C. and a load of 21.18 N.
[Propylene concentration in copolymer]
A sample dissolved in a mixed solvent of 1,2,4-trichlorobenzene / deuterated benzene was measured by ¹³ C-NMR method using JNM LA-400 ( ¹³ C resonance frequency 100 MHz) manufactured by JEOL Ltd. .

[Collecting xylene insoluble and xylene solubles]
2.5 g of the resin composition was placed in a flask containing 250 mL of o-xylene (solvent), and stirred for 30 minutes at 135 ° C. while purging with nitrogen using a hot plate and a reflux apparatus. Was completely dissolved and then cooled at 25 ° C. for 1 hour. The resulting solution was filtered using filter paper. At this time, acetone was added to the residue (mixture of xylene-insoluble component and solvent) remaining on the filter paper and filtered, and then the unfiltered component was evaporated to dryness in a vacuum drying oven set at 80 ° C. Insoluble matter was obtained.
100 mL of the filtrate after filtration when the xylene-insoluble matter was obtained was collected, transferred to an aluminum cup or the like, evaporated and dried at 140 ° C. while purging with nitrogen, and allowed to stand at room temperature for 30 minutes. A soluble content was obtained.
[XSIV]
Using the xylene-soluble matter as a sample, the intrinsic viscosity was measured in 135 ° C. tetrahydronaphthalene using an Ubbelohde viscometer (SS-780-H1, manufactured by Shibayama Scientific Instruments).

[Mw / Mn of xylene-insoluble matter]
Using the xylene-insoluble matter as a sample, the molecular weight distribution (Mw / Mn) was measured as follows:
PL GPC220 manufactured by Polymer Laboratories is used as an apparatus, 1,2,4-trichlorobenzene containing an antioxidant is used as a mobile phase, and UT-G (1), UT-807 (Showa Denko KK) is used as a column. 1) and UT-806M (2) connected in series were used, and a differential refractometer was used as a detector. Moreover, the same solvent as the mobile phase was used as the solvent for the sample solution of the xylene-insoluble matter, and the sample for measurement was prepared by dissolving at a sample concentration of 1 mg / mL for 2 hours while shaking at a temperature of 150 ° C. 500 μL of the sample solution thus obtained was injected into the column and measured at a flow rate of 1.0 mL / min, a temperature of 145 ° C., and a data acquisition interval of 1 second. For column calibration, a polystyrene standard sample (shodex STANDARD, manufactured by Showa Denko KK) having a molecular weight of 580 to 7.45 million was used and approximated by a cubic equation. The Mark-Houkins coefficients are K = 1.21 × 10 ⁻⁴ and α = 0.707 for the polystyrene standard sample, and K = 1.37 × 10 ⁻⁴ and α = 0. 75 was used.

[Strain hardening index]
A resin composition is molded to produce a prismatic measurement sample having a length of 60 mm, a thickness of 2 mm, and a width of 7 mm. Using the measurement sample, an elongational viscometer RME (manufactured by Rheometric Scientific) The extensional viscosity was measured under the conditions of measurement temperature: 200 ° C. and shear rate: 0.1 s ⁻¹ . From the measured elongational viscosity, the strain hardening index was determined as described above.

[Molding stability]
Inflation molding machine manufactured by Tommy Machine Industries Co., Ltd .: IFC-800-60-TWRJ (φ60mm), cylinder temperature 230 ° C, die temperature 250 ° C, blow ratio 2.2, film width 350mm (tube was crushed) The film was molded under the conditions of a folded diameter of the state, a molding speed of 18 m / min, and a film thickness of 60 μm.
Formability was evaluated by motor load (A) and bubble stability according to the following criteria.
5: Best 4: Good 3: Slightly good 2: Poor 1: Not moldable

[Fish eye]
The number of fish eyes of 0.1 mm or less generated in an area of 0.1 m ^{2 in} a 30 cm square film sample was visually counted using a magnifying loupe.
3: Less 2: Medium 1: Many

[Uneven thickness]
A continuous thickness gauge (TOF-4R05 manufactured by Yamabun Electric Co., Ltd.) measures a film of 700 mm in length (corresponding to the width when the tube is opened) at 5 mm intervals, and evaluates the difference between the maximum value and the minimum value. did.

[Production Example] Preparation of Solid Catalyst Component A solid catalyst component was prepared according to the preparation method described in Examples of JP2011-500907A. Specifically:
In a 500 mL 4-neck round bottom flask purged with nitrogen, 250 mL of TiCl ₄ was introduced at 0 ° C. While stirring, 10.0 g of fine spherical MgCl ₂ .1.8 C ₂ H ₅ OH (produced according to the method described in Example 2 of USP-4,399,054, but operating at 3000 rpm instead of 10000 rpm) ) And 9.1 mmol of diethyl-2,3- (diisopropyl) succinate was added. The temperature was raised to 100 ° C. and held for 120 minutes. Next, stirring was stopped, the solid product was allowed to settle, and the supernatant liquid was siphoned off. The following procedure was then repeated twice: 250 mL of fresh TiCl ₄ was added and the mixture was allowed to react at 120 ° C. for 60 minutes and the supernatant was siphoned off. The solid was washed 6 times with anhydrous hexane (6 × 100 mL) at 60 ° C.

[Example 1]
The above solid catalyst, triethylaluminum (TEAL) and dicyclopentyldimethoxysilane (DCPMS) are mixed in an amount such that the mass ratio of TEAL to the solid catalyst is 18 and the mass ratio of TEAL / DCPMS is 10 at room temperature. Touched for a minute. The resulting catalyst system was prepolymerized by holding it in liquid propylene in suspension for 5 minutes at 20 ° C.

  The obtained prepolymer was introduced into the first stage polymerization reactor to obtain a propylene homopolymer, and then the obtained polymer was introduced into the second stage polymerization reactor to obtain a copolymer (propylene -Ethylene copolymer) was polymerized. During the polymerization, temperature and pressure were adjusted, and hydrogen was used as a molecular weight modifier. The polymerization temperature and the ratio of the reactants are as follows: polymerization temperature and hydrogen concentration in the first-stage reactor are 70 ° C. and 0.19 mol%, respectively, polymerization temperature, hydrogen concentration, C2 / ( C2 + C3) were 80 ° C., 1.33 mol%, and 0.19 mol ratio, respectively. Further, the residence time distributions in the first and second stages were adjusted so that the amount of the copolymer component was 30% by weight. The obtained polypropylene polymer was blended with 0.2% by weight of B255 manufactured by BASF as an antioxidant and 0.05% by weight of calcium stearate manufactured by Tamnan Chemical Co., Ltd. as a neutralizing agent. The mixture was stirred and mixed for 1 minute at Nakatani Machinery Co., Ltd. NVCφ 50 mm single screw extruder, extruded at a cylinder temperature of 230 ° C., the strand was cooled in water, cut with a pelletizer, and a pellet-shaped polypropylene resin composition was prepared. Obtained.

  Subsequently, the polypropylene resin composition was subjected to inflation molding by the above method to obtain an inflation film. The resulting film was evaluated.

[Example 2]
The hydrogen concentration in the first-stage reactor is 0.15 mol%, the hydrogen concentration in the second-stage reactor, and C2 / (C2 + C3) are 2.21 mol% and 0.22 mol ratio, respectively. This was carried out in the same manner as in Example 1 except that the residence time distributions in the first and second stages were adjusted so that the amount of was 18% by weight.

[Example 3]
The hydrogen concentration in the first-stage reactor was 0.10 mol%, the hydrogen concentration in the second-stage reactor, and C2 / (C2 + C3) were 2.04 mol% and 0.13 mol ratio, respectively. This was carried out in the same manner as in Example 1 except that the residence time distributions in the first stage and the second stage were adjusted so as to be 33% by weight.

[Comparative Example 1]
A solid catalyst in which Ti and diisobutyl phthalate as an internal donor were supported on MgCl ₂ was prepared by the method described in Example 5 of European Patent No. 728769. Next, using the above solid catalyst, triethylaluminum (TEAL) as the organoaluminum compound and dicyclopentyldimethoxysilane (DCPMS) as the external electron donor compound, the weight ratio of TEAL to the solid catalyst is 20, and the weight ratio of TEAL / DCPMS. Was contacted at 12 ° C. for 24 minutes. The resulting catalyst system was preliminarily polymerized by keeping it in suspension in liquid propylene at 20 ° C. for 5 minutes. The obtained prepolymer is introduced into a first polymerization reactor of a polymerization apparatus equipped with a two-stage polymerization reactor in series to produce a propylene homopolymer, and ethylene-propylene is produced in the second polymerization reactor. A copolymer was produced. During the polymerization, temperature and pressure were adjusted, and hydrogen was used as a molecular weight modifier.

  The polymerization temperature and the ratio of the reactants are as follows: polymerization temperature and hydrogen concentration in the first stage reactor are 70 ° C. and 0.14 mol%, respectively, polymerization temperature, hydrogen concentration, C2 / ( C2 + C3) were 80 ° C., 1.52 mol%, and 0.44 mol ratio, respectively. Further, the residence time distributions in the first and second stages were adjusted so that the amount of the copolymer component was 27% by weight. Using this resin composition composition, an inflation film was produced and evaluated in the same manner as in Example 1.

[Comparative Example 2]
Comparison except that the hydrogen concentration in the first-stage reactor was 0.08 mol%, the hydrogen concentration in the second-stage reactor, and C2 / (C2 + C3) were 1.61 mol% and 0.30 mol ratio, respectively. Performed as in Example 1.
[Comparative Example 3]
The same operation as in Comparative Example 2 was performed except that the hydrogen concentration in the first-stage reactor was changed to 0.04 mol%.

[Comparative Example 4]
The hydrogen concentration in the first-stage reactor is 0.15 mol%, the hydrogen concentration in the second-stage reactor, and C2 / (C2 + C3) are 1.00 mol% and 0.44 mol ratio, respectively. This was carried out in the same manner as in Comparative Example 1 except that the residence time distributions in the first stage and the second stage were adjusted so as to be 21% by weight.

[Comparative Example 5]
Butene-1 was introduced into the second stage polymerization reactor instead of propylene to polymerize a copolymer (ethylene-butene-1 copolymer). The hydrogen concentration in the first-stage reactor is 0.08 mol%, and H2 / C2 and C4 / (C2 + C4) in the second-stage reactor are 0.13 mol ratio and 0.52 mol ratio, respectively. The residence time distribution in the first and second stages was adjusted so that the amount of the combined component was 30% by weight. Other than that was carried out in the same manner as in Comparative Example 1.

[Comparative Example 6]
Using a commercially available polypropylene homopolymer “PF-814” (manufactured by Sun Allomer Co., Ltd., MFR = 3.0 g / 10 min), an inflation film was produced and evaluated in the same manner as described above.
The molding stability was poor, and the resulting product was a wrinkled film in a wavy state, and uneven thickness could not be evaluated.
The results are shown in Table 1.

  From Table 1, it is clear that the resin composition of the present invention gives a film having excellent inflation moldability and less uneven thickness.

Claims (7)

A polypropylene resin composition in which a propylene-ethylene copolymer is dispersed in a propylene homopolymer,
The amount of the ethylene-propylene copolymer in the composition is 15 to 35% by weight;
The propylene content in the copolymer is 70 to 85% by weight,
The intrinsic viscosity (XSIV) of xylene solubles at 25 ° C. of the composition is 2 to 4 dl / g,
Mw / Mn of xylene insoluble matter at 25 ° C. of the composition is 7 to 12, and the melt flow rate at 230 ° C. and a load of 21.18 N of the composition is 0.1 to 10 g / 10 min.
The strain hardening index of the composition is greater than 1 and less than 10;
Polypropylene resin composition.   The resin composition according to claim 1, wherein the strain hardening index is more than 1 and 5 or less. (A) a solid catalyst containing, as an essential component, an electron donor compound selected from magnesium, titanium, halogen, and a succinate compound;
(B) an organoaluminum compound; and (C) obtained by polymerizing propylene and ethylene using a catalyst containing an external electron donor compound selected from silicon compounds.
The resin composition according to claim 1.   The inflation film manufactured using the resin composition in any one of Claims 1-3.   A sealant film for retort comprising the inflation film according to claim 4 in at least one layer. (A) a solid catalyst containing, as an essential component, an electron donor compound selected from magnesium, titanium, halogen, and a succinate compound;
(B) an organoaluminum compound; and (C) a step of polymerizing propylene and ethylene using a catalyst containing an external electron donor compound selected from silicon compounds.
The manufacturing method of the resin composition of Claim 1. Producing the resin composition by the method according to claim 6, and inflation molding the resin composition.
A method for producing a film.

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