JP5026319B2 - Laminated film - Google Patents

Description

  The present invention relates to a laminated film. Specifically, the present invention relates to a laminated film that has an excellent balance between impact resistance and transparency and is suitably used for shrink wrapping.

  Shrink wrapping is widely used to improve the commercial value of the package and to avoid direct impact on the exterior and contents, or to protect glass bottles and plastic bottles and display products. ing. Shrink packaging utilizes the property of shrinking (shrinking) by heating a stretched thermoplastic resin film.

  Shrink wrapping is generally performed by wrapping an item to be wrapped with a stretched thermoplastic resin film, piercing the stretched film with a needle or laser to create an air escape route, and heating to shrink the stretched film. Is called. It can also be carried out by wrapping an article to be wrapped with a stretched thermoplastic resin film that has been previously perforated and then shrinking the stretched film by heating.

As a thermoplastic resin material used for shrink wrapping, a film made of a polypropylene resin having excellent heat shrinkability and recyclability as described below is known.
Patent Document 1 contains 50 to 95 parts by weight of crystalline polypropylene (A) having a melt index of 0.1 to 20 and 5 to 50 parts by weight of propylene / 1-butene random copolymer (B). The propylene / 1-butene random copolymer (B) is derived from (1) propylene. The propylene / 1-butene random copolymer (B) is a film formed from the polypropylene composition and stretched in at least one direction of the machine direction and the transverse direction. The structural unit is contained in an amount of 50 to 95 mol%, the structural unit derived from 1-butene is contained in an amount of 5 to 50 mol%, and (2) the intrinsic viscosity [η] measured in decalin at 135 ° C. 0.1-3 dl / g, (3) Molecular weight distribution (Mw / Mn) determined by gel permeation chromatography (GPC) is 3 or less, and (4) Randomness of copolymer monomer chain distribution A shrink wrapping polypropylene film characterized by a parameter B value of 1.0 to 1.5 is disclosed, but this film is a single layer film.

  Patent Document 2 discloses a polymer obtained by random copolymerization of a C2-C20 α-olefin excluding polypropylene and propylene, and has a melting point range of 40 measured by differential scanning calorimetry (DSC). 1 to 20% by weight of a propylene / α-olefin random copolymer (A) having a content of α-olefin other than propylene of 5 to 70 mol% and 80 to 99% by weight of a polypropylene resin (B). A polypropylene resin composition formed from the above and a film formed from this polypropylene resin composition are formed into at least one layer, and a polyolefin resin composition is laminated thereon to form a multilayer film, which is oriented in a uniaxial or biaxial direction. A polypropylene stretched film is disclosed.

  By the way, in shrink wrapping, the film may be torn from small holes (holes made in the film to deaerate air taken in the packaged body) during packaging or transportation, or protrusions (of the packaged object) There is a problem that the film is torn by contact with a packaged body having a corner or the like.

From the above, the shrink wrapping film is required to have excellent heat shrinkability, transparency that affects the appearance, impact resistance (property that the film is difficult to tear or tear), and the like.
In the examples of Patent Documents 1 and 2, the heat shrinkability of the produced film is evaluated, but the impact resistance and transparency are not evaluated at all.
JP-A-9-278909 JP 2004-59652 A

  In the conventional stretched film for shrink wrapping, including the films disclosed in Patent Documents 1 and 2, the content of rubber components such as propylene / 1-butene (α-olefin random copolymer) copolymer Therefore, when a hole is made in a stretched film with a needle, a rubber component adheres to the needle, so that there is a problem that the needle needs to be washed.

  In view of the above, an object of the present invention is to provide a laminated film that is excellent in the balance between impact resistance and transparency and is suitably used for shrink wrapping.

The laminated film of the present invention is a stretched layer [I] made of polypropylene resin (i), and
(A) (1) containing units derived from propylene in an amount of 50 to 95 mol% and units derived from an α-olefin having 2 or 4 to 20 carbon atoms in an amount of 5 to 50 mol%,
(2) The melting point (Tm) measured by differential scanning calorimetry (DSC) is 110 ° C. or lower, or the melting point peak is not observed by DSC,
(3) The intrinsic viscosity [η] measured in decalin at 135 ° C. is 0.1 to 12 dl / g,
(4) a propylene / α-olefin copolymer having a molecular weight distribution (Mw / Mn) determined by gel permeation chromatography (GPC) of 3.0 or less;
(B) a polypropylene resin having a melting point of 120 ° C. or higher,
(A) / (B) is a laminated film having a stretched layer [II] made of a polypropylene resin composition contained at a weight ratio of 0.1 / 99.9 to 4.5 / 95.5.

The propylene / α-olefin copolymer (A) is:
(5) Melting | fusing point Tm measured by a differential scanning calorimeter is 50-110 degreeC, and this melting | fusing point Tm and the said C2-C20 or alpha-olefin structural unit content M (mol%) of 4-20. Relationship
It is preferable that −2.6M + 130 ≦ Tm ≦ −2.3M + 155.

The laminated film of the present invention preferably has an air vent hole that penetrates the stretched layer [I] and the stretched layer [II].
The propylene / α-olefin copolymer (A) is:
It is obtained by copolymerizing propylene and an α-olefin having 2 or 4 to 20 carbon atoms in the presence of a catalyst containing a transition metal compound (1a) represented by the following general formula (1a). Is preferred.

（式（１ａ）中、Ｒ¹、Ｒ³は水素であり、Ｒ²、Ｒ⁴は炭化水素基、ケイ素含有基から選ばれ、それぞれ同一でも異なっていてもよい。
Ｒ⁵、Ｒ⁶、Ｒ⁷、Ｒ⁸、Ｒ⁹、Ｒ¹⁰、Ｒ¹¹、Ｒ¹²、Ｒ¹³およびＲ¹⁴は水素、炭化水素基、
ケイ素含有基から選ばれ、それぞれ同一でも異なっていてもよく、Ｒ⁵からＲ¹²までの、
隣接する炭素に結合した置換基は互いに結合して環を形成してもよい。
Ｒ¹³とＲ¹⁴はそれぞれ同一でも異なっていてもよく、互いに結合して環を形成してもよい。
Ｍは第４族遷移金属であり、Ｙは炭素原子であり、Ｑはハロゲン、炭化水素基、アニオン配位子または孤立電子対で配位可能な中性配位子から同一または異なる組合せで選ばれ、ｊは１〜４の整数である。）

(In formula (1a), R ¹ and R ³ are hydrogen, and R ² and R ⁴ are selected from a hydrocarbon group and a silicon-containing group, and may be the same or different.
R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ and R ¹⁴ are hydrogen, a hydrocarbon group,
Selected from silicon-containing groups, each of which may be the same or different, from R ⁵ to R ¹² ,
Substituents bonded to adjacent carbons may be bonded to each other to form a ring.
R ¹³ and R ¹⁴ may be the same as or different from each other, and may be bonded to each other to form a ring.
M is a Group 4 transition metal, Y is a carbon atom, Q is selected from the same or different combinations from halogen, hydrocarbon groups, anionic ligands or neutral ligands that can coordinate with lone pairs J is an integer of 1 to 4. )

The polypropylene resin constituting the stretched layer [I] is preferably a propylene random copolymer having units derived from propylene and units derived from an α-olefin having 2 or 4 to 20 carbon atoms.

The polypropylene resin (B) constituting the stretched layer [II] is preferably a propylene homopolymer.
In the laminated film of the present invention, it is preferable that the stretched layer [I] has a thickness of 10 to 30 μm and the stretched layer [II] has a thickness of 5.0 to 30 μm.
The laminated film of the present invention can be suitably used for shrink wrapping.

  ADVANTAGE OF THE INVENTION According to this invention, it is excellent in the balance of impact resistance and transparency, and can provide the laminated | multilayer film used suitably for shrink packaging.

Hereinafter, the present invention will be specifically described.
The laminated film of the present invention has a stretched layer [I] made of polypropylene resin (i) and
It has a stretched layer [II] made of a polypropylene resin composition containing a specific propylene / α-olefin copolymer (A) and a specific polypropylene resin (B) in a specific ratio. In particular, the laminated film of the present invention is preferably a two-layer laminated film comprising only a stretched layer [I] and a stretched layer [II].

The laminated film of the present invention having such a laminated structure is prevented from being damaged by an excessive amount of heat when heat-sealing in shrink wrapping, and is useful for protecting a packaged body.
Hereinafter, the polypropylene resin (i), the propylene / α-olefin copolymer (A), the polypropylene resin (B), the propylene / α-olefin copolymer (A) and the polypropylene constituting the stretched layer [I]. It demonstrates in detail in order of the polypropylene-type resin composition which contains a system resin (B) in a specific ratio.

<Polypropylene resin (i) constituting stretched layer [I]>
The polypropylene resin (i) constituting the stretched layer [I] is not particularly limited, but usually D
A polypropylene resin having a melting point (Tm) measured by SC of 130 ° C. or higher is used. In the present invention, conventionally known polypropylene can be widely used as the polypropylene resin (i).

  The polypropylene resin (i) may be a homopolypropylene, and includes a propylene-based resin containing units derived from propylene and a small amount (for example, 10 mol% or less, preferably less than 5 mol%) of an olefin other than propylene. A copolymer may also be used. The copolymer may be a random copolymer or a block copolymer. Specific examples of the other olefin forming the propylene-based copolymer include α-olefins having 2 or 4 to 20 carbon atoms, and more specifically, ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-eicosene, 3-methyl-1-butene, 3-methyl-1- Pentene, 3-ethyl-1-pentene, 1-hexadecene, 4-methyl-1-pentene, 4-methyl-1-hexene, 3-ethyl-1-hexene, 9-methyl-1-decene, 11-methyl- Examples include 1-dodecene and 12-ethyl-1-tetradecene.

  In the present invention, a propylene random copolymer containing units derived from propylene and an α-olefin having 2 or 4 to 20 carbon atoms is usually used as the polypropylene resin (i). The α-olefin having 2 or 4 to 20 carbon atoms is preferably an α-olefin having 2 or 4 to 10 carbon atoms, and particularly preferably an α-olefin having 2 or 4 to 8 carbon atoms.

The polypropylene resin (i) used in the present invention can be produced by a known method using a conventionally known solid titanium catalyst component or metallocene compound catalyst component.
The polypropylene resin (i) used in the present invention usually has a melting point (Tm) of 130 ° C. or higher, preferably 130 to 170 ° C., more preferably 130 to 150 ° C. Polypropylene resin (i) having a melting point in this range is excellent in flexibility and stretchability. The polypropylene resin (i) usually has a higher melting point than the propylene / α-olefin copolymer (A) and the polypropylene resin (B) contained in the stretched layer [II] described later.

  Moreover, the melt flow rate MFR (ASTM D1238; 230 degreeC, 2.16kg load) of polypropylene resin (i) is 0.1-20 g / 10min normally, Preferably it is 1.0-10 g / 10min. It is desirable.

The said polypropylene resin can be used individually by 1 type or in combination of 2 or more types.
Moreover, the polypropylene resin (i) may contain an additive. Examples of the additive include an antistatic agent, a heat resistance stabilizer, an antioxidant, an ultraviolet absorber, a light stabilizer, an antiblocking agent, and a lubricant.

Examples of the antistatic agent include polyhydric alcohol fatty acid esters, higher fatty acid amines, higher fatty acid amides, higher fatty acid amines, and amide ethylene oxide adducts. The antistatic agent is usually added in an amount of 0.1% per 100 parts by weight of the polypropylene resin (i).
It is used in the range of 1 to 1.0 part by weight.

  Examples of the heat resistance stabilizer include fatty acid carboxylates, aromatic carboxylates, alkylphenolates, maleic acid monoester salts, alkyl mercaptides, mercapto acid ester salts, and the like. The heat stabilizer is usually used in an amount of 0.01 to 0.05 parts by weight per 100 parts by weight of the polypropylene resin (i).

Examples of the antioxidant include phosphorus antioxidants and phenolic antioxidants.
Examples of phosphorus antioxidants include tris (2,4-di-t-butylphenyl) phosphite, tetrakis (2,4-di-t-butylphenyl) -4,4′-biphenylene phosphonite, tris ( Nonylphenyl) phosphite, distearyl pentaerythritol diphosphite, bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite. The phosphorus-based antioxidant is usually used in a range of 0.05 to 0.2 parts by weight per 100 parts by weight of the polypropylene resin (i).

  Examples of phenolic antioxidants include 2,6-di-tert-butyl-4-methylphenol and 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate. 1,3,5-tris (4-t-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, tetrakis [methylene-3 (3 ', 5'di-t-butyl-4-hydroxy Phenyl) propionate] methane, octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) proponate. The phenolic antioxidant is usually used in the range of 0.01 to 0.03 parts by weight per 100 parts by weight of the polypropylene resin (i).

  Examples of the ultraviolet absorber include 2- (2H-benzotriazol-2-yl) -p-cresol and 2- (2H-benzotriazol-2-yl) -4-6-bis (1-methyl-1-phenyl). Ethyl) phenol, 2- [5-chloro (2H) -benzotriazol-2-yl] -4-methyl-6- (tert-butyl) phenol, 2,4-di-tert-butyl-6- (5- Chlorobenzotriazol-2-yl) phenol. The ultraviolet absorber is usually used in the range of 0.5 to 2.0 parts by weight per 100 parts by weight of the polypropylene resin (i).

  Examples of the light stabilizer include dimethyl succinate 1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine, poly [{6- (1,1,3,3, -Tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl} {2,2,6,6-tetramethyl-4-piperidyl} imino} hexamethylene {(2,2,6,6 -Tetramethyl-4-piperidyl) imino}], N, N′-bis (3-aminopropyl) ethylenediamine · 2,4-bis [N-butyl-N- (1,2,2,6,6-pentamethyl) -4-piperidyl) amino] -6-chloro-1,3,5-triazine. The light stabilizer is usually used in the range of 0.1 to 1.0 part by weight per 100 parts by weight of the polypropylene resin (i).

  Examples of the anti-blocking agent include silica, talc, mica, zeolite, polymethyl methacrylate, melamine formalin resin, melamine urea resin, and metal oxide particles obtained by firing metal alkoxide. The anti-blocking agent is usually used in the range of 0.05 to 1.0 part by weight per 100 parts by weight of the polypropylene resin (i).

Examples of lubricants include lauric acid amide, valmitic acid amide, stearic acid amide, behenic acid amide, erucic acid amide, oleic acid amide, bridic acid amide, elaidic acid mamide, methylene bis stearic acid amide, methylene bis oleic acid amide, ethylene Examples thereof include bis-stearic acid amide, ethylene bis-oleic acid amide, acetyl glyceride, polyglycerin fatty acid ester, and zinc stearate. The lubricant is usually used in an amount of 0.01 to 0.5 parts by weight per 100 parts by weight of the polypropylene resin (i).

<(A) Propylene / α-olefin copolymer>
The propylene / α-olefin copolymer (A) (hereinafter also simply referred to as copolymer (A)) used in the present invention satisfies the following requirements (1) to (4), and is preferably Satisfies one or more of the following requirements (5) and (6). By blending such a copolymer (A) into the polypropylene resin composition that forms the stretched layer [II], heat sealing at a lower temperature is possible than in the prior art, and the speed of heat sealing processing can be increased. I can expect. Particularly preferred copolymer (A) satisfies all the requirements of (1) to (6).

  (1) A unit derived from propylene is contained in an amount of 50 to 95 mol%, preferably 60 to 93 mol%, more preferably 70 to 90 mol%, and derived from an α-olefin having 2 or 4 to 20 carbon atoms. The unit to be removed is contained in an amount of 5 to 50 mol%, preferably 7 to 40 mol%, more preferably 10 to 30 mol%.

  When the unit derived from propylene is 50 mol% or less, the copolymer (A) becomes veiled, so that the handling property is extremely deteriorated. When the unit derived from propylene is 95 mol% or more, the combined polypropylene This is not preferable because it cannot be distinguished from the resin (B).

  The propylene / α-olefin copolymer (A) used in the present invention may contain a combination of a plurality of units derived from an α-olefin having 2 or 4 to 20 carbon atoms, but propylene and 1-butene. It is particularly preferable that it is composed only of units derived from

(2) The melting point (Tm) measured by differential scanning calorimetry (DSC) is 110 ° C. or lower, or no melting point peak is observed by DSC.
Preferably, the melting point (Tm) is 50 to 110 ° C, more preferably 60 to 100 ° C, and still more preferably 65 to 90 ° C. If the melting point is lower than 50 ° C., it becomes sticky at room temperature, and there is a high possibility of causing problems such as blocking.

(3) The intrinsic viscosity [η] measured in decalin at 135 ° C. is 0.1 to 12 dl / g, preferably 0.5 to 12 dl / g, more preferably 1 to 12 dl / g.
When the intrinsic viscosity [η] is greater than 12 dl / g, the fluidity of the resin composition containing the copolymer (A) and the polypropylene resin (B) described later is deteriorated, and sheet molding and stretching are difficult. Absent. When [η] is less than 0.1 dl / g, the mechanical strength such as impact resistance of the laminated film is lowered, which is not preferable.

  (4) The molecular weight distribution (Mw / Mn) determined by gel permeation chromatography (GPC) is 3.0 or less, preferably 2.0 to 3.0, more preferably 2.0 to 2. .5.

  When Mw / Mn is greater than 3.0, the copolymer (A) has a low molecular weight, so bleeding occurs from the surface layer of the laminated film, and the surface layer becomes sticky during storage of the laminated film, causing blocking. This is not preferable.

(5) Melting point Tm measured by a differential scanning calorimeter is 50 to 110 ° C., preferably 6
0 to 100 ° C., more preferably 65 to 90 ° C., and the relationship between the melting point Tm and the α-olefin structural unit content M (mol%) having 2 or 4 to 20 carbon atoms,
-2.6M + 130 ≦ Tm ≦ −2.3M + 155
Meet. When Tm and M satisfy the above relationship, a laminated film having excellent low-temperature heat sealability, high heat seal strength, and little reduction in seal strength due to aging after stretching can be obtained. In addition, a C2-C4 or C20 alpha olefin structural unit is a unit derived from a C2-C4 or C20 alpha olefin.

(6) Propylene / α-olefin comprising (i) three-chain propylene units bonded to the head-to-tail, or (ii) propylene units bonded to the head-to-tail and an α-olefin, wherein the second unit contains a propylene unit. When 3 chains were measured by ¹³ C-NMR spectrum (based on hexachlorobutadiene solution, tetramethylsilane) with respect to the side chain methyl group of the second propylene unit in the 3 chains, 19.5 to 21.9 ppm When the total area of the peak appearing in 100 is 100%, the peak area (triad tacticity) appearing in 21.0 to 21.9 ppm is 90% or more, preferably 92% or more, more preferably 94% or more. is there. When the triad tacticity showing stereoregularity is lower than 90%, the crystallinity is lowered, and the heat seal strength may be lowered.

The stereoregularity of the propylene / α-olefin copolymer (A) used in the present invention can be evaluated by triad tacticity (mm fraction).
For example, in the propylene / butene-1 random copolymer, this mm fraction is determined by the branching of the methyl group when the three head-to-tail bonded propylene unit chains existing in the polymer chain are represented by a surface zigzag structure. It is defined as the proportion of the same direction and is determined from the ¹³ C-NMR spectrum as follows.

When this mm fraction is determined from the ¹³ C-NMR spectrum, (i) three chains including propylene units present in the polymer chain, and (ii) The mm fraction is measured for a propylene unit / α-olefin unit triple chain composed of a head-to-tail bonded propylene unit and an α-olefin unit and the second unit being a propylene unit.

The mm fraction is determined from the peak intensity of the side chain methyl group of the second unit (propylene unit) in these three chains (i) and (ii). This will be described in detail below.
The ¹³ C-NMR spectrum of the propylene / α-olefin copolymer (A) is completely obtained in hexachlorobutadiene containing a small amount of deuterated benzene using the propylene / α-olefin copolymer (A) as a lock solvent in the sample tube. And then dissolved at 120 ° C. by a proton complete decoupling method. Measurement conditions, a flip angle was 45 °, the pulse interval 3.4T ₁ or more (T ₁ is the longest value among spin-lattice relaxation time of methyl groups) and. Since T ₁ of the methylene group and methine group is shorter than that of the methyl group, the recovery of the magnetization of all the carbon in the sample is 99% or more under this condition. The chemical shift is based on the methyl group carbon peak of the third unit of 5-chain (mmmm) propylene units bonded head-to-tail with tetramethylsilane as the reference, and the other carbon peaks are based on this.

Of the ¹³ C-NMR spectrum of the propylene / α-olefin copolymer thus measured, the methyl carbon region (about 19.5 to 21.9 ppm) in which the side chain methyl group of the propylene unit is observed is It is classified into 1 peak region (about 21.0 to 21.9 ppm), 2nd peak region (about 20.2 to 21.0 ppm), and 3rd peak region (about 19.5 to 20.2 ppm).

Within each of these regions, a head-to-tail trimolecular chain (i) and (i
A side chain methyl group peak of the second unit (propylene unit) in i) is observed.

表１中、Ｐはプロピレンから導かれる単位、Ｂはブテンなどのα−オレフィンから導かれる単位を示す。

In Table 1, P represents a unit derived from propylene, and B represents a unit derived from an α-olefin such as butene.

  Of the three head-to-tail linkages (i) and (ii) shown in Table 1, (i) methyl groups of PPP (mm), PPP (mr), and PPP (rr) in which all three linkages are composed of propylene units. The direction is illustrated by a surface zigzag structure below. (Ii) The mm, mr, and rr bonds of the three-chain (PPB, BPB) containing α-olefin units are based on this PPP.

第１領域では、ｍｍ結合したＰＰＰ、ＰＰＢ、ＢＰＢ３連鎖中の第２単位（プロピレン単位）目のメチル基が共鳴する。

In the first region, the methyl group of the second unit (propylene unit) in the mm-bonded PPP, PPB, BPB3 chain resonates.

  In the second region, the methyl group of the second unit (propylene unit) in the mr-bonded PPP, PPB, BPB3 chain and the methyl group of the second unit (propylene unit) in the rr-bonded PPB, BPB3 chain are resonant. To do.

In the third region, the methyl group of the second unit (propylene unit) of the rr-bonded PPP3 chain resonates.
Thus, the triad tacticity (mm fraction) of polypropylene consists of (i) a triple chain of head-to-tail bonded propylene units, or (ii) a head-to-tail bonded propylene unit and an α-olefin unit, and 3 units of propylene / α-olefin containing propylene units in the unit, and ¹³ C-NMR spectrum (based on hexachlorobutadiene solution, tetramethylsilane) for the side chain methyl group of the second unit propylene unit in the 3 chains The total area of the peak appearing in 19.5 to 21.9 ppm (methyl carbon region) is 100
%, The ratio of the area of the peak appearing in 21.0 to 21.9 ppm (first region) (
The percentage is obtained from the following formula.

本発明に係るプロピレン・α−オレフィン共重合体（Ａ）は、このようにして求められるｍｍ分率が、通常９０％以上、好ましくは９２％以上、より好ましくは９４％以上である。

In the propylene / α-olefin copolymer (A) according to the present invention, the mm fraction thus determined is usually 90% or more, preferably 92% or more, more preferably 94% or more.

  Polypropylene contains positional irregular units as shown in the following structures (iii), (iv), and (v) in addition to the head-to-tail linked three chains (i) and (ii) as described above. It has a small amount of partial structure, and a peak derived from the side chain methyl group of the propylene unit due to such other bonds is also observed in the methyl carbon region (19.5 to 21.9 ppm).

上記の構造(ｉｉｉ)、(ｉｖ)および(ｖ)に由来するメチル基のうち、メチル基炭素Ａおよびメチル基炭素Ｂは、それぞれ１７．３ｐｐｍ、１７．０ｐｐｍで共鳴するので、炭素Ａおよび炭素Ｂに基づくピークは、前記第１〜３領域(１９．５〜２１．９ｐｐｍ)内には現れない。さらにこの炭素Ａおよび炭素Ｂは、ともに頭−尾結合に基づくプロピレン３連鎖に関与しないので、上記のトリアドタクティシティ（ｍｍ分率）の計算では考慮する必要はない。

Of the methyl groups derived from the structures (iii), (iv) and (v), the methyl group carbon A and the methyl group carbon B resonate at 17.3 ppm and 17.0 ppm, respectively. The peak based on B does not appear in the first to third regions (19.5 to 21.9 ppm). Furthermore, since carbon A and carbon B are not involved in the propylene trilinkage based on the head-to-tail bond, it is not necessary to consider them in the calculation of the triad tacticity (mm fraction).

The peak based on the methyl group carbon C, the peak based on the methyl group carbon D, and the peak based on the methyl group carbon D ′ appear in the second region, and the peak based on the methyl group carbon E and the peak based on the methyl group carbon E ′ are Appears in the third region.

  Therefore, the 1st to 3rd methyl carbon regions include PPE-methyl group (side chain methyl group in propylene-propylene-ethylene chain) (around 20.7 ppm), EPE-methyl group (side in ethylene-propylene-ethylene chain). (Chain methyl group) (around 19.8 ppm), peaks based on methyl group C, methyl group D, methyl group D ′, methyl group E, and methyl group E ′ appear.

  Thus, in the methyl carbon region, peaks of methyl groups that are not based on the head-to-tail bond triple chain (i) and (ii) are also observed. It is corrected as follows.

The peak area based on the PPE-methyl group can be obtained from the peak area of the PPE-methine group (resonant at around 30.6 ppm), and the peak area based on the EPE-methyl group is determined based on the EPE-methine group (around 32.9 ppm). Resonance) peak area. The peak area based on the methyl group C can be determined from the peak area of the adjacent methine group (resonance near 31.3 ppm). The peak area based on the methyl group D can be obtained from 1/2 of the sum of the peak areas of the peaks (resonance around 34.3 ppm and 34.5 ppm) based on the αβ methylene carbon of the structure (iv). The peak area based on the group D ′ can be determined from the area of the peak (resonance around 33.3 ppm) based on the methine group adjacent to the methyl group of the structure (v) methyl group E ′. The peak area based on the methyl group E can be obtained from the peak area of the adjacent methine carbon (resonant at around 33.7 ppm), and the peak area based on the methyl group E ′ is determined at the adjacent methine carbon (around 33.3 ppm). Resonance) peak area.

  Accordingly, by subtracting these peak areas from the total peak areas of the second region and the third region, the peak area of the methyl group based on the head-to-tail three-linked propylene units (i) and (ii) can be obtained. .

As described above, the peak area of the methyl group based on the head-to-tail-bonded propylene unit triple chain (i) and (ii) can be evaluated, and the mm fraction can be obtained according to the above formula. Each carbon peak in the spectrum can be assigned with reference to literature (Polymer, 30, 1350 (1989)).

  The melt flow rate (ASTM D1238, temperature 230 ° C., load 2.16 kgf) of the propylene / α-olefin copolymer (A) used in the present invention is usually 0.1 to 30 g / 10 min, preferably 0.5 to 20 g / 10 min, more preferably 1.0 to 10 g / 10 min.

  Such a propylene / α-olefin copolymer (A) used in the present invention comprises a metallocene containing propylene, an α-olefin having 2 or 4 to 20 carbon atoms and, if necessary, a small amount of other olefins. It can obtain suitably by copolymerizing in presence of the catalyst containing a compound, Preferably, it can manufacture by the method as described in WO2004 / 088775 pamphlet or WO01 / 27124 pamphlet.

  More preferably, the propylene / α-olefin copolymer (A) used in the present invention is prepared by using propylene and carbon in the presence of a catalyst containing a transition metal compound (1a) represented by the following general formula (1a). It is desirable to be obtained by copolymerizing an α-olefin of the number 2 or 4-20. The transition metal compound (1a) is a compound in which a ligand in which a substituted cyclopentadienyl ring and a substituted fluorenyl ring are bridged with carbon is coordinated to a transition metal atom.

  Here, the catalyst containing the transition metal compound (1a) is (2a) an organometallic compound, (2b) an organoaluminum oxy compound, and (2c) a compound that forms an ion pair by reacting with the transition metal compound (1a). And a catalyst containing at least one compound selected from the above and the transition metal compound (1a).

（式（１ａ）中、Ｒ¹、Ｒ³は水素であり、Ｒ²、Ｒ⁴は炭化水素基、ケイ素含有基から選ばれ、それぞれ同一でも異なっていてもよい。Ｒ⁵、Ｒ⁶、Ｒ⁷、Ｒ⁸、Ｒ⁹、Ｒ¹⁰、Ｒ¹¹、Ｒ¹²、Ｒ¹³およびＲ¹⁴は水素、炭化水素基、ケイ素含有基から選ばれ、それぞれ同一でも異
なっていてもよく、Ｒ⁵からＲ¹²までの、隣接した炭素に結合した置換基は互いに結合し
て環を形成してもよい。Ｒ¹³とＲ¹⁴はそれぞれ同一でも異なっていてもよく、互いに結合して環を形成してもよい。Ｍは第４族遷移金属であり、Ｙは炭素原子であり、Ｑはハロゲン、炭化水素基、アニオン配位子または孤立電子対で配位可能な中性配位子から同一または異なる組合せで選ばれ、ｊは１〜４の整数である。）

(In the formula (1a), R ¹ and R ³ are hydrogen, and R ² and R ⁴ are selected from a hydrocarbon group and a silicon-containing group, and may be the same or different. R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ and R ¹⁴ are selected from hydrogen, a hydrocarbon group, and a silicon-containing group, and may be the same or different, and R ⁵ to R ¹² Substituents bonded to adjacent carbon atoms may be bonded to each other to form a ring, and R ¹³ and R ¹⁴ may be the same or different from each other, and may be bonded to each other to form a ring. M is a Group 4 transition metal, Y is a carbon atom, and Q is the same or different combination from a halogen, a hydrocarbon group, an anionic ligand, or a neutral ligand capable of coordinating with a lone pair of electrons. And j is an integer from 1 to 4.)

Examples of the hydrocarbon group include methyl group, ethyl group, n-propyl group, allyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, and n-nonyl. Group, a linear hydrocarbon group such as n-decanyl group;
Isopropyl group, tert-butyl group, amyl group, 3-methylpentyl group, 1,1-diethylpropyl group, 1,1-dimethylbutyl group, 1-methyl-1-propylbutyl group, 1,1-propylbutyl group Branched hydrocarbon groups such as 1,1-dimethyl-2-methylpropyl group, 1-methyl-1-isopropyl-2-methylpropyl group;
A cyclic saturated hydrocarbon group such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a norbornyl group, an adamantyl group;
Cyclic unsaturated hydrocarbon groups such as phenyl group, tolyl group, naphthyl group, biphenyl group, phenanthryl group, anthracenyl group;
A saturated hydrocarbon group substituted with a cyclic unsaturated hydrocarbon group such as benzyl group, cumyl group, 1,1-diphenylethyl group, triphenylmethyl group;
Examples include heteroatom-containing hydrocarbon groups such as methoxy group, ethoxy group, phenoxy group, furyl group, N-methylamino group, N, N-dimethylamino group, N-phenylamino group, pyryl group, and thienyl group. it can.

  Examples of the silicon-containing group include a trimethylsilyl group, a triethylsilyl group, a dimethylphenylsilyl group, a diphenylmethylsilyl group, and a triphenylsilyl group.

In addition, substituents bonded to adjacent carbons from R ⁵ to R ¹² may be bonded to each other to form a ring. Examples of such substituted fluorenyl groups include benzofluorenyl group, dibenzofluorenyl group, octahydrodibenzofluorenyl group, octamethyloctahydrodibenzofluorenyl group, octamethyltetrahydrodicyclopentafluorenyl group, etc. Can be mentioned.

R ¹³ and R ¹⁴ are preferably aryl groups. Examples of the aryl group include the above-mentioned cyclic unsaturated hydrocarbon group, a saturated hydrocarbon group substituted with a cyclic unsaturated hydrocarbon group, a heteroatom-containing cyclic unsaturated hydrocarbon group such as a furyl group, a pyryl group, and a thienyl group. Can be mentioned. R ¹³ and R ¹⁴ may be the same or different, and may be bonded to each other to form a ring.

R ² which is a substituent bonded to the cyclopentadienyl ring in the general formula (1a),
R ⁴ is preferably a hydrocarbon group having 1 to 20 carbon atoms. Examples of the hydrocarbon group having 1 to 20 carbon atoms include the aforementioned hydrocarbon groups. Among these, R ² is more preferably a bulky substituent such as a tert-butyl group, an adamantyl group, or a triphenylmethyl group, and R ⁴ is more preferable than R ² such as a methyl group, an ethyl group, or an n-propyl group. It is more preferably a sterically small substituent. The term “sterically small” as used herein means that the volume occupied by the substituent is small.

In the general formula (1a), among R ⁵ to R ¹² which are substituents bonded to the fluorenyl ring, any two or more of R ⁶ , R ⁷ , R ¹⁰ and R ¹¹ have 1 to 20 carbon atoms. The hydrocarbon group is preferably. Examples of the hydrocarbon group having 1 to 20 carbon atoms include the aforementioned hydrocarbon groups. In particular, from the viewpoint of ease of synthesis of the ligand, it is preferable that R ⁶ and R ¹¹ and R ⁷ and R ¹⁰ are the same group. Among such preferred embodiments, R ⁶ and R ⁷ form an aliphatic ring (AR-1), and R ¹⁰ and R ¹¹ are the same aliphatic ring (AR-1). The case where (AR-2) is formed is also included.

In the said General formula (1a), Y which bridge | crosslinks a cyclopentadienyl ring and a fluorenyl ring is a carbon atom. It is preferable that R ¹³ and R ¹⁴ which are substituents bonded to Y are simultaneously an aryl group having 6 to 20 carbon atoms. Examples of the aryl group having 6 to 20 carbon atoms include the above-mentioned cyclic unsaturated hydrocarbon group, a saturated hydrocarbon group substituted with a cyclic unsaturated hydrocarbon group, and a heteroatom-containing cyclic unsaturated hydrocarbon group. R ¹³ and R ¹⁴ may be the same or different, and may be bonded to each other to form a ring. As such a substituent, a fluorenylidene group, a 10-hydroanthracenylidene group, a dibenzocycloheptadienylidene group, and the like are preferable.

In the general formula (1a), M is a Group 4 transition metal, and specific examples thereof include Ti, Zr, and Hf.
Q is selected from the same or different combinations from halogen, a hydrocarbon group, an anionic ligand, or a neutral ligand capable of coordinating with a lone pair of electrons. j is an integer of 1 to 4, and when j is 2 or more, a plurality of Qs may be the same or different from each other.

  Specific examples of the halogen include fluorine, chlorine, bromine and iodine, and specific examples of the hydrocarbon group include the same as described above. Specific examples of the anionic ligand include alkoxy groups such as methoxy, tert-butoxy and phenoxy, carboxylate groups such as acetate and benzoate, and sulfonate groups such as mesylate and tosylate. Specific examples of neutral ligands that can be coordinated by a lone pair include organophosphorus compounds such as trimethylphosphine, triethylphosphine, triphenylphosphine, diphenylmethylphosphine, tetrahydrofuran, diethyl ether, dioxane, 1,2-dimethoxy. And ethers such as ethane. It is preferable that at least one Q is a halogen or an alkyl group.

Examples of such a transition metal compound (1a) include dimethylmethylene (3-tert-butyl-5-methylcyclopentadienyl) fluorenylzirconium dichloride, isopropylidene (3-tert-butyl-5-methylcyclopenta). Dienyl) (2,7-di-tert-butylfluorenyl) zirconium dichloride, isopropylidene (3-tert-butyl-5-methylcyclopentadienyl) (3,6-di-tert-butylfluorenyl) ) Zirconium dichloride, isopropylidene (3-tert-butyl-5-methylcyclopentadienyl) (octamethyloctahydridodibenzfluorenyl) zirconium dichloride, diphenylmethylene (3-tert-butyl-5-methylcyclopentadi) Enil) (fluore Nyl) zirconium dichloride, diphenylmethylene (3-tert-butyl-5-methylcyclopentadienyl) (2,7-di-tert-butylfluorenyl) zirconium dichloride, diphenylmethylene (3-tert-butyl-5- Methylcyclopentadienyl) (3,6-di-tert-butylfluorenyl) zirconium dichloride, diphenylmethylene (3-tert-butyl-5-methylcyclopentadienyl) (octamethyloctahydridodibenzfluorenyl) ) Zirconium dichloride and the like, but are not limited thereto.

  The catalyst suitably used for producing the propylene / α-olefin copolymer (A) used in the present invention includes (2a) an organometallic compound and (2b) an organic compound together with the transition metal compound (1a) described above. It contains at least one compound selected from an aluminum oxy compound and (2c) a compound that reacts with a transition metal compound (1a) to form an ion pair. These compounds (2a), (2b), and (2c) are not particularly limited, but preferred examples include the compounds described in WO 2004/088775 pamphlet or WO 01/27124 pamphlet. Can be mentioned.

(2a) As the organometallic compound, the following Group 1, 2 and Group 12, 13 organometallic compounds are used.
(2a-1) General formula: R ^a _m Al (OR ^b ) _n H _p X _q
(In the formula, R ^a and R ^b may be the same or different from each other, each represents a hydrocarbon group having 1 to 15 carbon atoms, preferably 1 to 4 carbon atoms, X represents a halogen atom, and m represents 0 < m ≦ 3, n is 0 ≦ n <3, p is a number of 0 ≦ p <3, q is a number of 0 ≦ q <3, and m + n + p + q = 3).

  Specific examples of such compounds include trimethylaluminum, triethylaluminum, triisobutylaluminum, diisobutylaluminum hydride and the like.

(2a-2) General formula: M ² AlR ^a ₄
(Wherein M ² represents Li, Na, or K, and R ^a represents a hydrocarbon group having 1 to 15 carbon atoms, preferably 1 to 4 carbon atoms). Alkylates.
Examples of such a compound include LiAl (C ₂ H ₅ ) ₄ and LiAl (C ₇ H ₁₅ ) ₄ .

(2a-3) General formula: R ^a R ^b M ³
(In the formula, R ^a and R ^b may be the same or different from each other, and each represents a hydrocarbon group having 1 to 15 carbon atoms, preferably 1 to 4 carbon atoms, and M ³ is Mg, Zn or Cd) Second represented by
Dialkyl compounds of Group 12 or Group 12 metals.

  Of these organometallic compounds (2a), organoaluminum compounds are preferred. Moreover, such an organometallic compound (2a) may be used individually by 1 type, and may be used in combination of 2 or more type.

(2b) The organoaluminum oxy compound may be a conventionally known aluminoxane or a benzene-insoluble organoaluminum oxy compound exemplified in JP-A-2-78687.

A conventionally well-known aluminoxane can be manufactured, for example with the following method, and is normally obtained as a solution of a hydrocarbon solvent.
1) Compounds containing adsorbed water or salts containing water of crystallization, such as magnesium chloride hydrate, copper sulfate hydrate, aluminum sulfate hydrate, nickel sulfate hydrate, first cerium chloride hydrate, etc. A method in which an organoaluminum compound such as trialkylaluminum is added to a hydrocarbon medium suspension and the adsorbed water or crystal water reacts with the organoaluminum compound. 2) A method in which water, ice or water vapor is allowed to act directly on an organoaluminum compound such as trialkylaluminum in a medium such as benzene, toluene, diethyl ether or tetrahydrofuran.
3) A method of reacting an organotin oxide such as dimethyltin oxide or dibutyltin oxide with an organoaluminum compound such as trialkylaluminum in a medium such as decane, benzene, or toluene.

  The aluminoxane may contain a small amount of an organometallic component other than aluminoxane. Further, after removing the solvent or the unreacted organoaluminum compound from the recovered aluminoxane solution by distillation, it may be redissolved in a solvent or suspended in a poor aluminoxane solvent. Specific examples of the organoaluminum compound used when preparing the aluminoxane include the same organoaluminum compounds as those exemplified as the organoaluminum compound belonging to the above (2a-1). Of these, trialkylaluminum and tricycloalkylaluminum are preferable, and trimethylaluminum is particularly preferable. The above organoaluminum compounds are used singly or in combination of two or more.

  The benzene-insoluble organoaluminum oxy compound is dissolved in benzene at 60 ° C. (the organoaluminum oxy compound corresponding to 100 milligrams of aluminum is suspended in 100 ml of benzene and mixed at 60 ° C. with stirring for 6 hours. After that, it is filtered while heated at 60 ° C. using a jacketed G5 glass filter, and the solid separated on the filter is washed 4 times with 50 ml of benzene at 60 ° C. to collect the filtrate, and the aluminum present in the filtrate It is usually determined by measuring the abundance (mmol) of atoms) in terms of aluminum atom, which is usually 10 mmol or less, preferably 5 mmol or less, particularly preferably 2 mmol or less. Those which are insoluble or hardly soluble are preferred. These organoaluminum oxy compounds (2b) are used singly or in combination of two or more.

  (2c) Examples of the compound that reacts with the transition metal compound (1a) to form an ion pair include JP-A-1-501950, JP-A-1-502036, JP-A-3-179005, and JP-A-3- And Lewis acids, ionic compounds, borane compounds and carborane compounds described in JP-A No. 179006, JP-A-3-207703, JP-A-3-207704, USP-5321106, and the like. Furthermore, heteropoly compounds and isopoly compounds can also be mentioned. Such a compound of (2c) is used individually by 1 type or in combination of 2 or more types.

  In the production of the propylene / α-olefin copolymer (A) used in the present invention, when a catalyst is used in combination with the transition metal compound (1a) and an organoaluminum oxy compound (2b) such as methylaluminoxane, in particular, It is preferable because high polymerization activity can be achieved.

In addition, the polymerization catalyst used in the production of the propylene / α-olefin copolymer (A) used in the present invention may be one using a carrier as necessary, and includes other promoter components. It may be a thing.

Such a catalyst may be prepared by mixing each component in advance or by supporting it on a carrier, or may be used by adding each component simultaneously or sequentially to the polymerization system.
The propylene / α-olefin copolymer (A) used in the present invention is preferably propylene and an α-olefin having 2 or 4 to 20 carbon atoms, particularly preferably 1 in the presence of the above-mentioned catalyst. -It is obtained by copolymerizing butene with a small amount of other olefins if necessary. In the copolymerization, each monomer may be used in such an amount that each constituent unit amount in the produced propylene / α-olefin copolymer (A) is in a desired ratio, specifically, propylene / α-olefin. The molar ratio is 50/50 to 95/5, preferably 60/40 to 93/7, and more preferably 70/30 to 90/10.

  The copolymerization conditions are not particularly limited. For example, the polymerization temperature is usually in the range of −50 to + 200 ° C., preferably 0 to 170 ° C., and the polymerization pressure is usually normal pressure to 10 MPa gauge pressure, preferably normal pressure to It can be performed under the condition of 5 MPa gauge pressure. The polymerization reaction can be carried out in any of batch, semi-continuous and continuous methods. Furthermore, the polymerization can be carried out in two or more stages having different reaction conditions. The molecular weight of the propylene / α-olefin copolymer (A) can be adjusted by allowing hydrogen to be present in the polymerization system or changing the polymerization temperature, and (2a), (2b) or It can also be adjusted by the amount of (2c). When hydrogen is added, the amount is suitably about 0.001 to 100 NL per kg of monomer.

<(B) Polypropylene resin>
The polypropylene resin (B) used in the present invention has a melting point of 120 ° C. or higher.
As such a polypropylene resin (B), a polypropylene resin having a melting point (Tm) measured by DSC of 120 ° C. or more can be used without limitation. In the present invention, conventionally known as a polypropylene resin (B). The polypropylene can be widely used.

  The polypropylene resin (B) may be homopolypropylene, and includes a propylene-based resin containing units derived from propylene and a small amount (for example, 10 mol% or less, preferably less than 5 mol%) of an olefin other than propylene. A copolymer may also be used. In the present invention, the polypropylene resin (B) is preferably homopolypropylene, that is, a propylene homopolymer.

The copolymer may be a random copolymer or a block copolymer. In the present invention, a propylene random copolymer is preferably used among the copolymers.
Specific examples of the other olefins forming the propylene random copolymer include α-olefins having 2 to 20 carbon atoms other than propylene, and more specifically, ethylene, 1-butene, 1-pentene. 1-hexene, 1-heptene, 1-octene, 1-decene, 1-dodecene, 1-hexadecene, 4-methyl-1-pentene, and the like.

  The polypropylene resin (B) used in the present invention is preferably a polypropylene produced by a known method using a conventionally known solid titanium catalyst component. Polypropylene obtained using a metallocene compound catalyst component can also be used.

  The polypropylene resin (B) used in the present invention has a melting point (Tm) of 120 ° C. or higher, preferably 120 to 170 ° C., more preferably 120 to 160 ° C., and further preferably 130 to 150 ° C. When the melting point is in this range, a laminated film having an excellent balance between impact resistance and low temperature heat sealability can be obtained.

  Among the polypropylenes having such a melting point, the polypropylene resin (B) includes the melting point (TmB) of the polypropylene resin (B) and the melting point (TmA) of the propylene / α-olefin copolymer (A) described above. A polypropylene having a difference (TmB-TmA) of 10 to 100 ° C., preferably 20 to 100 ° C., is desirable.

The polypropylene resin (B) has a melt flow rate MFR (ASTMD 1238; 230 ° C., under a load of 2.16 kg) of usually 0.1 to 400 g / 10 minutes, preferably 0.5 to 100 g / 10 minutes.
The polypropylene resin (B) used in the present invention usually has a higher hardness than the propylene / α-olefin copolymer (A).

<Polypropylene resin composition containing propylene / α-olefin copolymer (A) and polypropylene resin (B) at a specific ratio>
A polypropylene resin composition (hereinafter also simply referred to as a resin composition) containing a specific proportion of the propylene / α-olefin copolymer (A) and the polypropylene resin (B) used in the present invention is (A) Propylene / α-olefin copolymer and (B) polypropylene resin have a weight ratio of (A) / (B) of 0.1 / 99.9 to 4.5 / 95.5, preferably 2. It is included at a ratio of 0 / 98.0 to 4.5 / 95.5. By including the copolymer (A) and the polypropylene resin (B) at such a ratio, a laminated film excellent in the balance between impact resistance and transparency can be obtained without lowering the heat seal strength.

  In the present invention, by reducing the content of the copolymer (A) as described above, even when a hole is made in the stretched film with a needle, the rubber component does not adhere to the needle, so a hole was made in the stretched film. The problem of having to clean the needle later is also solved by the present invention.

Moreover, in the resin composition used for this invention, additives, such as antioxidant, a lubricant, and an antiblocking agent, can be added as needed in the range which does not impair the objective of this invention.
In the present invention, as a method for preparing a polypropylene resin composition containing the copolymer (A) and the polypropylene resin (B), any conventionally known method can be employed. For example, a V-type blender, Examples thereof include a method of mixing with a mixer such as a ribbon blender and a Henschel mixer, and a method of kneading with a kneader such as an extruder, mixing roll, Banbury mixer and kneader. Moreover, you may combine these methods.

The resin composition obtained by mixing may be prepared in the form of pellets or granules, and is directly molded into a molded body such as a film or sheet that becomes the stretched layer [II] made of the resin composition. Also good.
Next, the stretched layer [I] and the stretched layer [II] constituting the laminated film of the present invention and the method for producing the laminated film will be described.

<Stretched layer [I] and Stretched layer [II]>
In the present invention, the stretched layer [I] is a stretched layer formed from the polypropylene resin (i). The thickness of the stretched layer [I] is usually 10 to 60 μm, preferably 10 to 30 μm, from the viewpoint of scratch resistance and whitening resistance of the laminated film.

In the present invention, the stretched layer [II] is a stretched layer formed from a polypropylene resin composition containing the propylene / α-olefin copolymer (A) and the polypropylene resin (B) in a specific ratio. The thickness of the stretched layer [II] is usually 0.5 to 40 μm, preferably 5.0 to 30 μm, from the viewpoint of exhibiting an effect of improving impact resistance.
The stretched layer refers to a layer that has been stretched in any step during the production of the laminated film of the present invention.

<Method for producing laminated film>
The production method of the laminated film having the stretched layer [I] and the stretched layer [II] is not particularly limited, and can be produced, for example, by the following method.

  (1): The polypropylene resin (i) and the polypropylene resin composition are coextruded using a T-die or the like such as a single manifold method or a multi-manifold method to form a laminate, A method for producing a laminated film of the present invention by stretching a laminate.

  (2): The polypropylene resin (i) is melt-extruded to form a film or sheet made of the polypropylene resin (i), and uniaxially or biaxially stretched as necessary, on the film or sheet. A method in which the polypropylene resin composition is melt extruded and the resulting laminate is stretched.

  (3): The polypropylene resin (i) is melt-extruded to form a film or sheet made of the polypropylene resin (i), uniaxially or biaxially stretched, and previously molded on the film or sheet. And a method of obtaining a laminated film of the present invention by laminating a stretched film or sheet made of the polypropylene resin composition.

  In the method (3), when the film or sheet made of the polypropylene resin composition is laminated on the film or sheet made of the polypropylene resin (i), they are usually laminated by bonding with an adhesive.

  In the above methods (1), (2) and (3), stretching is performed in at least one direction of the machine direction (MD direction) and the transverse direction (TD direction), and the laminated film of the present invention is a uniaxially stretched film or It is a biaxially stretched film.

There is no restriction | limiting in particular as an extending | stretching method, For example, a well-known arbitrary extending | stretching method, for example, a batch method, T-die shaping | molding method, a tube method, an inflation shaping | molding method, a tenter method etc., can be employ | adopted.
Examples of the stretch molding method include a uniaxial stretching method and a biaxial stretching method.

  As a batch method, cut into a predetermined size from what was obtained by previously forming a single-layer or multi-layer unstretched sheet, and fixed by sandwiching both ends in the vertical and horizontal directions of the unstretched sheet with clips, A table-type stretching machine having a tank for softening and stretching the unstretched sheet by heating and a tank for cooling the stretched film (some machines may be used in one kind of tank). Stretched and biaxially stretched films can be obtained.

  In the case of the uniaxial stretching method, the unstretched sheet or film obtained by T-die molding or inflation molding is usually cooled and then introduced between the slow (front) drive roll and the fast (rear) drive roll. For example, a stretched film can be obtained by stretching in the longitudinal direction at a predetermined magnification.

  When stretching by the tenter method using an extruder equipped with a T die, the temperature on the inlet side of the extruder is usually in the temperature range of 140 to 200 ° C, and the temperature on the outlet side of the extruder is 200 to 300 ° C. By setting the temperature range of the die and the temperature of the die in the temperature range of 200 to 280 ° C, extruding from the T die so that the resin temperature is in the range of 200 ° C to 280 ° C, and stretching to a desired aspect ratio can get.

When uniaxially stretching an unstretched film obtained by inflation molding, the temperature on the inlet side of the extruder is usually in the temperature range of 130 to 180 ° C, the temperature on the outlet side of the extruder is in the temperature range of 140 to 260 ° C, It is obtained by setting the temperature of the ring die in a temperature range of 140 to 250 ° C., extruding from the ring die so that the resin temperature is in the range of 140 to 250 ° C., and stretching to a desired aspect ratio. Moreover, when using resin with slow crystallization, the film extruded from the ring die is water-cooled as needed, and a stretched film is obtained.

Examples of the biaxial stretching method include a tenter method and a tube method.
In the case of the tenter method, the raw material is usually melt-kneaded with an extruder and extruded from a T-die, and the obtained melt-kneaded product is cooled and solidified on a casting drum, and then a slow (front) drive roll and a speed (rear) It is introduced between the drive rolls and stretched at a predetermined magnification in the longitudinal direction, and then the film stretched in the longitudinal direction is put in a tenter and further stretched in the lateral direction while holding both ends and heating. Thus, a biaxially stretched film is obtained.

  In the case of the tube method, the raw material is usually melted and kneaded with an extruder, the molten resin is extruded into a tube shape from a ring die, rapidly cooled in a cooling tank, and then the tube-shaped material is heated to air inside. A biaxially stretched film can be obtained by introducing and pressurizing or depressurizing the outside of the tube and stretching in the transverse direction while applying tension in the longitudinal direction and stretching in the longitudinal direction.

  The draw ratio is usually 3 to 10 times, preferably 4 to 9 times, respectively in the longitudinal direction and the transverse direction. When stretching is performed so that the stretching ratio is within the above range, a laminated film in which the molecular orientation inside the film is sufficient and sufficient heat shrinkage can be obtained by heat treatment can be obtained. There is no cut.

  As the method for producing the laminated film of the present invention, the method (1) is a production method suitable for mass production, and it is also preferable for the transparency of the laminated film and the uniform shrinkage during shrink packaging.

The laminated film of the present invention formed as described above is excellent in the balance between impact resistance and transparency, and is suitably used for shrink wrapping.
When used for shrink wrapping, for example, the object to be packaged is wrapped with the laminated film of the present invention, the laminated film is heat sealed, and a stretched layer [I] is applied to the laminated film with a needle or a laser.
And the shrink wrapping can be performed by making a hole for air bleeding penetrating the stretched layer [II] and heating. The air vent hole may be formed before the packaged body is wrapped with the laminated film.

EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.
In addition, 1-butene content, molecular weight distribution, melting point, intrinsic viscosity [η] and melt flow rate, piercing strength, tear strength, transparency, heat sealability and shrinkage dimensional change of the polymer obtained in the production example About the rate, it tested by the following methods.

(1) 1-butene content
^It calculated | required using < ¹³ > C-NMR.

(2) Molecular weight distribution The molecular weight distribution (Mw / Mn) was determined by measurement by GPC (gel permeation chromatography). For the measurement, a gel permeation chromatograph Alliance GPC-2000 manufactured by Waters was used. As separation columns, two TSKgel GNH6-HT and two TSKgel GNH6-HTL were used, both of which had a diameter of 7.5 mm and a length of 300 mm, a column temperature of 140 ° C., and a mobile phase. Was transferred at 1.0 ml / min using o-dichlorobenzene (Wako Pure Chemical Industries) and BHT (Takeda Pharmaceutical) 0.025% by weight as an antioxidant, and the sample concentration was 15 mg / 10 ml. The amount was 500 microliters, and a differential refractometer was used as a detector. As the standard polystyrene, those manufactured by Tosoh Corporation were used for molecular weights of Mw <1000 and Mw> 4 × 10 ⁶ , and those manufactured by Pressure Chemical Co. were used for 1000 ≦ Mw ≦ 4 × 10 ⁶ . Mw represents a weight average molecular weight, and Mn represents a number average molecular weight.

(3) Melting point The melting point (Tm) of the polymer was 10 ° C / min after the polymer sample held at 240 ° C for 10 minutes was cooled to 30 ° C and held for 5 minutes by differential scanning calorimetry (DSC). It was calculated from the crystal melting peak when the temperature was raised at.

(4) Intrinsic viscosity [η]
Measurements were taken at 135 ° C. decalin and expressed in dl / g.

(5) Melt flow rate (MFR)
It measured by the method of ASTM D1238 on condition of 230 degreeC and a 2.16kg load.

(6) Puncture strength A semi-circular needle having a diameter of 1/2 inch and a tip shape diameter of 1/4 inch is pierced into the fixed laminated film at a speed of 200 mm / min, and the maximum load when the needle penetrates the laminated film. It was measured. The ambient temperature during measurement was 23 ± 2 ° C.

(7) Tear strength The tear strength was measured according to the Elmendorf tear method defined in JIS K7128-2.

(8) Transparency (haze)
Total haze and internal haze were measured according to ASTM D1003.

(9) Heat sealability (heat seal adhesive strength)
The stretched layers [II] of the laminated film composed of the polypropylene resin composition (B) are overlapped with each other and heat sealed in a transverse direction with a seal bar having a width of 5 mm at a temperature of 160 ° C. and a pressure of 0.2 MPa for 1 second. And then allowed to cool. Subsequently, each of the laminated films including the heat seal portion cut into a strip shape having a width of 15 mm in the horizontal direction and a length of 100 mm in the vertical direction was used as a test piece. The heat seal part of the test piece is opened at 180 ° in the center, both ends of the test piece are attached to the grip of the tensile tester, and a tensile load is applied until the heat seal part breaks at a crosshead speed of 300 mm / min. The maximum load (N / 15 mm) was measured.

(10) Shrinkage dimensional change rate The shrinkage dimensional change rate was measured in accordance with the B method defined in JIS C2330. However, the annealing conditions (pretreatment) of the laminated film were (a) warm water at 80 ° C. for 10 seconds, (b) warm water at 90 ° C. for 10 seconds, and (c) air oven at 40 ° C. for 7 days. The dimensional change after performing was measured.

[Production Example 1]
[Production of propylene / 1-butene copolymer]
Specifically, the propylene / 1-butene copolymer was scaled up according to the following method to obtain a required amount of polymer.

  Into a 2 liter polymerization vessel sufficiently purged with nitrogen, 866 ml of dry hexane and 90 g of 1-butene were added, 1 mmol of triisobutylaluminum was added, the internal temperature of the polymerization vessel was raised to 65 ° C., and propylene was added. The pressure was supplied to 0.7 MPa.

  Next, 0.002 mmol of dimethylmethylene (3-tert-butyl-5-methylcyclopentadienyl) fluorenylzirconium dichloride is contacted with 0.6 mmol of methylaluminoxane (produced by Tosoh Finechem) in terms of aluminum. 200 ml of the toluene solution was added into the polymerization vessel, polymerized for 30 minutes while maintaining an internal temperature of 65 ° C. and a propylene pressure of 0.7 MPa, and 20 ml of methanol was added to terminate the polymerization.

After depressurization, the polymer was precipitated from the polymerization solution in methanol in a 2 liter container, and dried under reduced pressure at 130 ° C. for 12 hours. The yield of the obtained polymer was 12.5 g.
This polymer has a content of structural units derived from 1-butene of 28 mol%, a melt flow rate (ASTM D1238, temperature 230 ° C., load 2.16 kgf) of 7.0 g / 10 min. The obtained molecular weight distribution (Mw / Mn) was 2.1, the melting point (Tm) was 75 ° C., and the intrinsic viscosity [η] measured in decalin at 135 ° C. was 1.90 dl / g.

  Further, the obtained polymer was melted so that the temperature of the polymer became 230 ° C. with a single screw extruder (screw diameter φ40 mm, manufactured by Sumitomo Heavy Industries Modern) equipped with a pelletizer to produce pellets.

[Example 1]
Polypropylene resin (i) having an ethylene content of 2.2 mol%, a melt flow rate (ASTM D1238, temperature 230 ° C., load 2.16 kgf) of 7.0 g / 10 min and a melting point of 138 ° C. (manufactured by Prime Polymer Co., Ltd.) Prime Polypro F327) was applied to the stretched layer [I].

  Next, the propylene / 1-butene copolymer (A) obtained in Production Example 1 above, an ethylene content of 3.4 mol%, a melt flow rate (ASTM D1238, temperature 230 ° C., load 2.16 kgf) Is 2.6 g / 10 min, and a propylene random copolymer resin (Prime Polypro F233DR manufactured by Prime Polymer Co., Ltd.) (B) having a melting point of 128 ° C. and a weight ratio of (A) / (B) is 1.0 / 99.0. The blended material that was weighed in the ratio and mixed with a Henshur mixer was used for the stretched layer [II].

For the production of the laminated film, a two-type two-layer sheet forming machine (two connected screw diameter φ30 mm extruders equipped with a T-die for molding, manufactured by GM Engineering Co., Ltd.) is used. T-die so that the layer formed from the polypropylene resin (i) and the layer formed from the compounding material are laminated in the state where the resin (i) and the compounding material are melt-kneaded separately and the resin temperature is 240 ° C. To a thickness of 250 μm (a layer formed from the polypropylene resin (i) (a layer to be a stretched layer [I]) is 100 μm thick, a layer formed from a blended material (a layer to be a stretched layer [II]) The unstretched laminate was adjusted to have a thickness of 150 μm.

Further, the obtained unstretched laminate was cut into a size of 90 cm in the longitudinal direction and 90 cm in the lateral direction, heated at 120 ° C. for 1 minute with a batch type stretching machine (manufactured by Bruckner), and then unstretched. The film was stretched 5 times in the machine direction at a tensile rate of 10 m / min, held for 20 seconds, then air-cooled, and a uniaxially stretched laminated film having a thickness of 50 μm (stretched layer [I] had a thickness of 20 μm and stretched layer [II ] Was 30 μm.
The puncture strength, tear strength, transparency, heat sealability and shrinkage dimensional change rate of the obtained laminated film were tested by the above methods. The results are shown in Table 2.

[Example 2]
In Example 1, the amounts of the propylene / 1-butene copolymer (A) and the propylene random copolymer resin (B) obtained in Production Example 1 to be used for the stretched layer [II] are set to (A) / (B ) Was changed to an amount such that the weight ratio was 2.0 / 98.0, and a uniaxially stretched laminated film having a thickness of 50 μm was obtained in the same manner as in Example 1.
The puncture strength, tear strength, transparency, heat sealability and shrinkage dimensional change rate of the obtained laminated film were tested by the above methods. The results are shown in Table 2.

[Example 3]
In Example 1, the amounts of the propylene / 1-butene copolymer (A) and the propylene random copolymer resin (B) obtained in Production Example 1 to be used for the stretched layer [II] are set to (A) / (B ) Was changed to an amount such that the weight ratio was 3.0 / 97.0, and a uniaxially stretched laminated film having a thickness of 50 μm was obtained in the same manner as in Example 1.
The puncture strength, tear strength, transparency, heat sealability and shrinkage dimensional change rate of the obtained laminated film were tested by the above methods. The results are shown in Table 2.

[Example 4]
In Example 1, the amounts of the propylene / 1-butene copolymer (A) and the propylene random copolymer resin (B) obtained in Production Example 1 to be used for the stretched layer [II] are set to (A) / (B ) Was changed to an amount such that the weight ratio was 4.5 / 95.5, and a uniaxially stretched laminated film having a thickness of 50 μm was obtained in the same manner as in Example 1.
The puncture strength, tear strength, transparency, heat sealability and shrinkage dimensional change rate of the obtained laminated film were tested by the above methods. The results are shown in Table 2.

[Comparative Example 1]
In Example 1, a 50 μm-thickness was obtained in the same manner as in Example 1 except that the propylene / 1-butene copolymer (A) obtained in Production Example 1 provided for the stretched layer [II] was not used. A monoaxially stretched laminated film was obtained.
The puncture strength, tear strength, transparency, heat sealability and shrinkage dimensional change rate of the obtained laminated film were tested by the above methods. The results are shown in Table 2.

[Comparative Example 2]
In Example 1, the amounts of the propylene / 1-butene copolymer (A) and the propylene random copolymer resin (B) obtained in Production Example 1 to be used for the stretched layer [II] are set to (A) / (B ) Was changed to an amount such that the weight ratio was 10.0 / 90.0, and a uniaxially stretched laminated film having a thickness of 50 μm was obtained in the same manner as in Example 1.
The puncture strength, tear strength, transparency, heat sealability and shrinkage dimensional change rate of the obtained laminated film were tested by the above methods. The results are shown in Table 2.

Claims (8)

Stretched layer [I] composed of homopolypropylene and at least one polypropylene resin (i) selected from propylene and a propylene copolymer containing units derived from olefins other than propylene and 10 mol% or less of propylene ,
(A) (1) containing units derived from propylene in an amount of 50 to 95 mol% and units derived from an α-olefin having 2 or 4 to 20 carbon atoms in an amount of 5 to 50 mol%,
(2) The melting point (Tm) measured by differential scanning calorimetry (DSC) is 110 ° C. or lower, or the melting point peak is not observed by DSC,
(3) The intrinsic viscosity [η] measured in decalin at 135 ° C. is 0.1 to 12 dl / g,
(4) a propylene / α-olefin copolymer having a molecular weight distribution (Mw / Mn) determined by gel permeation chromatography (GPC) of 3.0 or less;
(B) a polypropylene resin having a melting point of 120 ° C. or higher,
A laminated film having a stretched layer [II] made of a polypropylene resin composition that is contained at a weight ratio of (A) / (B) of 0.1 / 99.9 to 4.5 / 95.5. The propylene / α-olefin copolymer (A) is
(5) Melting | fusing point Tm measured by a differential scanning calorimeter is 50-110 degreeC, and this melting | fusing point Tm and the said C2-C20 or alpha-olefin structural unit content M (mol%) of 4-20. Relationship
The laminated film according to claim 1, wherein −2.6M + 130 ≦ Tm ≦ −2.3M + 155.   3. The laminated film according to claim 1, further comprising an air vent hole penetrating through the stretched layer [I] and the stretched layer [II]. The propylene / α-olefin copolymer (A) is
It is obtained by copolymerizing propylene and an α-olefin having 2 or 4 to 20 carbon atoms in the presence of a catalyst containing a transition metal compound (1a) represented by the following general formula (1a). The laminated film according to any one of claims 1 to 3.

(In formula (1a), R ¹ and R ³ are hydrogen, and R ² and R ⁴ are selected from a hydrocarbon group and a silicon-containing group, and may be the same or different.
R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ and R ¹⁴ are selected from hydrogen, a hydrocarbon group, and a silicon-containing group, and may be the same or different. Often, the substituents attached to adjacent carbons from R ⁵ to R ¹² may be joined together to form a ring.
R ¹³ and R ¹⁴ may be the same as or different from each other, and may be bonded to each other to form a ring.
M is a Group 4 transition metal, Y is a carbon atom, Q is selected from the same or different combinations from halogen, hydrocarbon groups, anionic ligands or neutral ligands that can coordinate with lone pairs And
j is an integer of 1-4. )   The polypropylene resin (i) is a propylene random copolymer having units derived from propylene and units derived from an α-olefin having 2 or 4 to 20 carbon atoms. A laminated film according to any one of the above.   The laminated film according to any one of claims 1 to 5, wherein the polypropylene resin (B) is a propylene homopolymer. The stretched layer [I] has a thickness of 10 to 30 μm,
The laminated film according to any one of claims 1 to 6, wherein the stretched layer [II] has a thickness of 5.0 to 30 µm.   The laminated film according to claim 1, wherein the laminated film is used for shrink packaging.