JP2016074760A - Stretched film, production method thereof, and packaging material using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stretched film in which unevenness of thickness is less than in the conventional film.SOLUTION: A stretched film includes one or more layers composed of a polyolefin-based composition including: (a) an olefinic polymer (A) having a melting point (Tm-D), defined by an apex of a peak observed on the highest temperature side of a melting endothermic curve obtained by retaining a sample in nitrogen atmosphere at -10°C for five minutes and subsequently raising the temperature at 10°C/min while using a differential scanning calorimeter (DSC), of higher than 120°C; and (b) an olefinic polymer (B) having a melting endotherm (ΔH-D) obtained from the melting endothermic curve obtained by retaining a sample in nitrogen atmosphere at -10°C for five minutes and subsequently raising the temperature at 10°C/min while using a differential scanning calorimeter (DSC), of 0-80 J/g, and having molecular weight distribution (Mw/Mn) of less than 3.0, and the thickness of the layer is 30 to 400 μm.SELECTED DRAWING: None

Description

  The present invention relates to a stretched film, a production method thereof, and a packaging material using the same.

Polypropylene resin is particularly excellent because it is excellent in strength, rigidity, heat resistance, chemical stability, transparency, lightness, etc., and because it is a hydrocarbon resin, it is excellent in food hygiene such as non-toxicity and odorlessness. Widely used in the food field.
For example, when used in the food container field, it is molded and used by methods such as extrusion molding and injection molding. In particular, many plastic containers such as plastic beverage bottles are manufactured by blow molding of a resin material. Conventionally, polyethylene, polypropylene, polyvinyl chloride, and polyethylene terephthalate have been mainly used as materials used mainly. However, crystalline resins such as polypropylene are not suitable for use in transparent containers that replace glass bottles because of their poor transparency and gloss. On the other hand, polypropylene resins have high expectations for transparent containers from the viewpoints of chemical stability, light weight, and recyclability compared to polyvinyl chloride / polyethylene terephthalate resins. Therefore, various studies have been made to improve transparency and gloss (for example, Patent Documents 1 to 3).
Further, when used in the food packaging field, it is often used in the form of a film. Examples of film production methods include a water-cooled inflation method, an air-cooled inflation method, and a T-die molding method. Among the films, in particular, the biaxially oriented polypropylene film has characteristics such as moderate mechanical properties, excellent transparency, and light weight, and is widely used for labeling and releasing applications including various packaging. In recent years, by utilizing the low surface energy of polypropylene film, mold release suitable for the manufacturing process of thermosetting resin members such as crosslinked silicone sheet, epoxy resin base, unsaturated polyester member, fiber reinforced plastic, etc. Widely used as a material. When used for such mold release, dimensional stability is required to improve handling in the process, and heat resistance is increased and a film thickness is required to be increased.

  In addition, as a method for improving the transparency of the propylene polymer, a propylene polymer using a metallocene catalyst, a method using a propylene / α-olefin copolymer, a method of adding a crystal nucleating agent, and a combination thereof have been proposed. ing. However, with the former method, there are problems that impair rigidity and heat resistance, and with the latter sheet, there is a problem of smoke generation during sheet forming, and these sheets are used for thermoforming such as vacuum forming and vacuum / pressure forming. When the molded product is molded with, thickness unevenness occurs. Transparency and glossiness are extremely impaired, and its use is limited (for example, Patent Document 1).

On the other hand, if a polyolefin-based resin such as polyethylene or polypropylene is molded by blow molding with stretching (stretch blow molding), the transparency and gloss are improved. For this reason, biaxial stretch blow molding by a one-stage hot parison method in which an injection molding machine and a blow molding machine are integrated is used in part. However, since this method uses a hot parison heated by injection molding, tearing is likely to occur due to unevenness in thickness during stretch blow molding due to temperature fluctuations, residual stress, etc. during injection molding. For this reason, since the draw ratio cannot be increased, it has been difficult to obtain a molded article having high transparency and high gloss such as polyethylene terephthalate.
Also, even when trying to use a resin material with high transferability and high MFR (melt flow rate) to improve transparency and gloss, the parison can be released from the injection mold due to the high temperature of the parison. As a result, since a resin material having a high MFR cannot be used, there is a problem that transparency and gloss are inferior.

As an attempt to obtain a thick sheet without reducing the heat resistance, a method for defining the low molecular weight component and melting point of the polypropylene resin used has been proposed (for example, Patent Document 4).
In addition, as a method of suppressing the low molecular weight component and not increasing the melting point until it becomes difficult to stretch, a method of using a polypropylene / butene copolymer (for example, Patent Document 5) or a polypropylene polymer having a high melt tension is added to polypropylene. A method (for example, Patent Document 6) has been proposed.
However, when the polypropylene resin is selected in the former method, it is difficult to obtain a uniform and thick biaxially oriented polypropylene film because the stretchability deteriorates, and in particular, a film having a thickness exceeding 60 μm Due to the non-uniform film thickness, it was difficult to produce industrially. For this reason, attempts have been made to use two sheets of biaxially oriented polypropylene films or other materials such as polyester films to produce a thick film and use it as a release film. Although the latter is improved as compared with the former, the problem of heat resistance is not solved as compared with the homopolypropylene resin.

JP 2013-233694 A JP 2004-066565 A JP 2000-313778 A JP 2001-146536 A JP 2007-254731 A JP 2006-63186 A

  This invention is made | formed in view of the said situation, and it aims at providing the stretched film with few thickness nonuniformity compared with the conventional stretched film.

As a result of intensive studies, the present inventors have achieved the above object by blending the olefin polymer (B) having a specific structure with a relatively low melting endotherm into the polyolefin composition. I found out. The present invention has been completed based on such findings.
That is, the present invention provides the following inventions.
[1] A stretched film comprising at least one layer composed of a polyolefin-based composition containing the following components (a) and (b), wherein the layer has a thickness of 30 μm or more and 400 μm or less.
(A) Using a differential scanning calorimeter (DSC), hold the sample at −10 ° C. for 5 minutes in a nitrogen atmosphere, and then raise the temperature at 10 ° C./min. Olefin polymer (A) whose melting point (Tm-D) defined as the observed peak top exceeds 120 ° C
(B) Using a differential scanning calorimeter (DSC), the sample was held at −10 ° C. for 5 minutes in a nitrogen atmosphere, and then heated at 10 ° C./min. Olefin polymer (B) having a calorific value (ΔH-D) of 0 to 80 J / g and a molecular weight distribution (Mw / Mn) of less than 3.0
[2] The above (b) component of the polyolefin composition is 0.5% by mass or more and less than 50% by mass with respect to 100% by mass of the total amount of the (a) and (b) components. 1].
[3] The stretched film according to the above [1] or [2], wherein the olefin polymer (A) is a propylene polymer (a1).
[4] Stretching according to any one of [1] to [3], wherein 50 mol% or more of the olefin polymer (B) is a propylene polymer (b1) composed of a propylene monomer. the film.
[5] The stretched film according to the above [4], wherein the propylene polymer (b1) satisfies the following (i) and / or (ii).
(I) The structural unit of ethylene is contained in excess of 0 mol% and 20 mol% or less.
(Ii) The structural unit of 1-butene is contained in an amount exceeding 0 mol% and not more than 30 mol%.
[6] The stretched film according to [4], wherein the propylene polymer (b1) satisfies the following (1).
(1) [mmmm] is 20 to 60 mol%
[7] The stretched film according to any one of [4] to [6], wherein the propylene polymer (b1) satisfies the following (2).
(2) Using a differential scanning calorimeter (DSC), hold the sample at −10 ° C. for 5 minutes in a nitrogen atmosphere, and then raise the temperature at 10 ° C./min. The melting point (Tm-D) defined as the observed peak top is 0-120 ° C.
[8] The stretched film according to [6], wherein the propylene polymer (b1) satisfies the following (2) and (3).
(2) Using a differential scanning calorimeter (DSC), hold the sample at −10 ° C. for 5 minutes in a nitrogen atmosphere, and then raise the temperature at 10 ° C./min. The melting point (Tm-D) defined as the observed peak top is 0-120 ° C.
(3) [rrrr] / (1- [mmmm]) ≦ 0.1
[9] The stretched film according to the above [6] or [8], wherein the propylene polymer (b1) satisfies the following (4) and (5).
(4) [rmrm]> 2.5 mol%
(5) [mm] × [rr] / [mr] ² ≦ 2.0
[10] A film including one or more layers made of the polyolefin-based composition according to any one of [1] to [9] is uniaxially or biaxially so that the thickness of the layer is 30 μm or more and 400 μm or less. A method for producing a stretched film obtained by simultaneous or sequential stretching.
[11] A packaging material comprising the stretched film according to any one of [1] to [9].

  According to this invention, compared with the conventional stretched film, a stretched film with little thickness nonuniformity can be provided. Moreover, the packaging material etc. which consist of this stretched film are excellent in heat resistance, an optical characteristic (for example, haze, gloss), and a dynamic characteristic (for example, elastic modulus).

  The present invention is described below. In addition, in this specification, the term "-" regarding description of a numerical value is a term which shows more than the lower limit and below an upper limit. Moreover, in this specification, (a) component and an olefin polymer (A) and (b) component and an olefin polymer (B) are synonymous.

[Stretched film]
The stretched film of the present invention is a stretched film comprising at least one layer composed of a polyolefin-based composition containing the following components (a) and (b), wherein the thickness of the layer is from 30 μm to 400 μm.
(A) Using a differential scanning calorimeter (DSC), hold the sample at −10 ° C. for 5 minutes in a nitrogen atmosphere, and then raise the temperature at 10 ° C./min. Olefin polymer (A) whose melting point (Tm-D) defined as the observed peak top exceeds 120 ° C
(B) Using a differential scanning calorimeter (DSC), the sample was held at −10 ° C. for 5 minutes in a nitrogen atmosphere, and then heated at 10 ° C./min. Olefin polymer (B) having a calorific value (ΔH-D) of 0 to 80 J / g and a molecular weight distribution (Mw / Mn) of less than 3.0

In the stretched film of the present invention, the component (b) of the polyolefin-based composition is preferably 0.5% by mass or more with respect to a total amount of 100% by mass with the components (a) and (b). Less than 50% by mass, more preferably 0.5% by mass or more and less than 20% by mass, still more preferably 0.5% by mass or more and less than 15% by mass, still more preferably 1% by mass or more and less than 10% by mass. It is.
Hereafter, each component used for this invention and a manufacturing method are demonstrated one by one.

<Olefin polymer (A)>
The olefin polymer (A), which is the component (a) used in the present invention, was held at −10 ° C. for 5 minutes in a nitrogen atmosphere using a differential scanning calorimeter (DSC), and then 10 ° C./min. The melting point (Tm-D) defined as the peak top that is observed on the highest temperature side of the melting endothermic curve obtained by raising the temperature at 150 ° C. exceeds 120 ° C. When the melting point (Tm-D) is 120 ° C. or lower, there arises a problem that the heat resistance of a molded body using the polyolefin-based composition, for example, a film is inferior. From such a viewpoint, the melting point (Tm-D) is preferably 125 ° C. or higher, more preferably 140 ° C. or higher, still more preferably 150 ° C. or higher, and still more preferably 160 ° C. or higher.
In addition, this melting | fusing point (Tm-D) is a value measured by the method as described in the Example mentioned later.

The olefin polymer (A) of the present embodiment is preferably an olefin polymer obtained by polymerizing one or more monomers selected from, for example, ethylene and an α-olefin having 3 to 28 carbon atoms.
Examples of the α-olefin having 3 to 28 carbon atoms include propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1-undecene and 1- Examples include dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene and 1-icocene. Among these, Preferably it is C3-C24 alpha-olefin, More preferably, it is C3-C12 alpha-olefin, More preferably, it is C3-C6 alpha-olefin, Most preferably, it is C3-C4 An α-olefin, most preferably propylene.
An olefin polymer obtained by polymerizing one of these alone may be used, or an olefin copolymer obtained by copolymerizing two or more of them may be used. In the present specification, the term “olefin polymer” includes an olefin copolymer. Examples of the olefin copolymer include an ethylene polymer in which 50 mol% or more of the monomers constituting the polymer are ethylene monomers, and a propylene polymer in which 50 mol% or more of the monomers constituting the polymer are propylene monomers ( a1), a butene-based polymer in which 50 mol% or more of the monomers constituting the polymer are butene monomers, and the like, and a molded article having excellent properties from the viewpoint of rigidity and transparency, for example, film properties can be obtained. The polymer (a1) is more preferable. Further, the propylene polymer (a1) has a mesopentad fraction [mmmm] described later of preferably 70 to 98 mol%, more preferably 80 to 98 mol%, and still more preferably, from the viewpoint of improving rigidity and transparency. It is 85-97.5 mol%, More preferably, it is 87-97 mol%, More preferably, it is 88-96 mol%, More preferably, it is 90-92 mol%.
As propylene polymer (a1), propylene homopolymer, propylene-ethylene block copolymer, propylene-butene block copolymer, propylene-α-olefin block copolymer, propylene-ethylene random copolymer, propylene A propylene-based polymer (a1) selected from a -butene random copolymer, a propylene-α-olefin random copolymer, a propylene-α-olefin graft copolymer, and the like is preferable. Furthermore, the olefin polymer (a1) of the present invention is particularly preferably a propylene-ethylene random copolymer or propylene from the viewpoint of the physical properties of the molded body, for example, the physical properties of the stretched film (for example, mechanical physical properties, optical physical properties). It is a homopolymer. The polymer may be a polymer using a petroleum / coal-derived monomer or a polymer using a biomass-derived monomer.

  As content of the olefin polymer (A) in a polyolefin-type composition, it is 50 with respect to the total content of 100 mass% of the olefin polymer (B) mentioned later and the said olefin polymer (A). It is at least mass%. When the content is less than 50% by mass, the stretched film or sheet using the polyolefin-based composition has a problem that heat resistance is lowered. From such a viewpoint, the content of the olefin polymer (A) in the polyolefin composition is 100 total content of the olefin polymer (B) and the olefin polymer (A) described later. Preferably it is 80 mass% or more with respect to the mass%, More preferably, it is 85 mass% or more, More preferably, it is 90 mass%. Moreover, from the viewpoint of transparency and heat resistance of a stretched film using the polyolefin-based composition, it is preferably 98% by mass or less, more preferably 95% by mass or less.

<Olefin polymer (B)>
The olefin polymer (B), which is the component (b) used in the present invention, was held at −10 ° C. for 5 minutes in a nitrogen atmosphere using a differential scanning calorimeter (DSC), then 10 ° C./min. The melting endotherm (ΔH-D) obtained from the melting endotherm curve obtained by raising the temperature at 0 to 0-80 J / g, and the molecular weight distribution (Mw / Mn) is less than 3.0.
The olefin polymer (B) of the present invention is preferably an olefin polymer (B) obtained by polymerizing one or more monomers selected from ethylene and an α-olefin having 3 to 28 carbon atoms.
Examples of the α-olefin having 3 to 28 carbon atoms include propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1-undecene and 1- Examples include dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene and 1-icocene. Among these, Preferably it is C3-C24 alpha-olefin, More preferably, it is C3-C12 alpha-olefin, More preferably, it is C3-C6 alpha-olefin, Most preferably, it is C3-C4 An α-olefin, most preferably propylene.
An olefin polymer (B) obtained by polymerizing one of these alone may be used, or an olefin copolymer (B) obtained by copolymerizing two or more in combination. Also good. As the olefin copolymer (B), an ethylene polymer in which 50 mol% or more of the monomers constituting the polymer is an ethylene monomer, or a propylene polymer in which 50 mol% or more of the monomers constituting the polymer is a propylene monomer Examples include polymer (b1), butene-based polymers in which 50 mol% or more of monomers constituting the polymer are butene monomers, and excellent molded article physical properties such as film physical properties from the viewpoint of transparency and suppression of stretching unevenness. The propylene-based polymer (b1) from which can be obtained is more preferable.
As propylene polymer (b1), propylene homopolymer, propylene-ethylene block copolymer, propylene-butene block copolymer, propylene-α-olefin block copolymer, propylene-ethylene random copolymer, propylene It is preferably a propylene polymer (b1) selected from a butene random copolymer, a propylene-α-olefin random copolymer, a propylene-α-olefin graft copolymer, and the like, and in particular, a propylene homopolymer Is preferred.

  Moreover, in the polyolefin-type composition of this invention, when the olefin polymer (A) which is a main component is a propylene-type polymer (a1), a compatible viewpoint with the main component propylene-type polymer (a1). In the case where the propylene polymer (b1) is a copolymer containing an olefin having 2 carbon atoms, the constituent unit of the olefin having 2 carbons (that is, ethylene monomer) is preferably 0 mol%. More than 20 mol%, more preferably more than 0 mol%, less than 18 mol%, still more preferably more than 0 mol%, less than 15 mol%, still more preferably more than 0 mol% and less than 13 mol% It is. In the case of a copolymer containing an olefin having 3 carbon atoms, the constituent unit of the olefin having 3 carbon atoms (that is, propylene monomer) is preferably 50 mol% or more, more preferably 65 mol% or more. More preferably, it is 75 mol% or more, and still more preferably 80 mol% or more. In the case of a copolymer containing an α-olefin having 4 or more carbon atoms, the content of the α-olefin having 4 or more carbon atoms is preferably more than 0 mol% and 30 mol% or less, more preferably 0. More than mol% and 27 mol% or less, more preferably more than 0 mol% and 20 mol% or less. Moreover, in the polyolefin-type composition of this invention, when the olefin polymer (A) which is a main component is a propylene-type polymer (a1), a compatible viewpoint with the main component propylene-type polymer (a1). From the above, the olefin polymer (B) of the present invention is most preferably a propylene homopolymer. The polymer may be a polymer using a petroleum / coal-derived monomer or a polymer using a biomass-derived monomer.

Since the polyolefin-based composition of the present invention contains the olefin-based polymer (B), the proportion of the amorphous component is increased, and the yield stress when the polyolefin-based composition is stretched is reduced. It improves and the tenacity of a molded object, for example, the formed film, improves.
In particular, from the viewpoint of greatly improving the uniform stretchability of the polyolefin-based composition, in order to increase the ratio of the amorphous component in the polyolefin-based composition, the content of the olefin-based polymer (B) is The total content of the polymer (B) and the olefin polymer (A) is preferably 100% by mass or more and less than 50% by mass, more preferably 0.5% by mass. % Or more and less than 20% by mass, more preferably 0.5% by mass or more and less than 15% by mass, still more preferably 1% by mass or more and less than 10% by mass.
In particular, when the olefin polymer (A) is a propylene polymer (a1) and the olefin polymer (B) is a propylene polymer (b1), the propylene polymer. The compatibility of the propylene-based polymer (b1) with respect to (a1) becomes better, and a molded product having more excellent transparency and stretchability can be obtained.

  The olefin polymer (B) has the following melting endotherm (ΔH-D) and molecular weight distribution (Mw / Mn) from the viewpoint of greatly improving stretchability without affecting the mechanical properties of the molded body. And having the characteristics described later (particularly, in the case of the propylene polymer (b1)), the content of the olefin polymer (B) is in the above-described range. preferable.

(Melting endotherm (ΔH-D))
The melting endotherm (ΔH-D) of the olefin polymer (B) and the propylene polymer (b1) is 0 to 80 J / g. When the melting endotherm (ΔH-D) of the olefin polymer (B) and the propylene polymer (b1) is 0 to 80 J / g, it is a main component of the polyolefin composition suitable for the stretched film of the present invention. The crystallinity is reduced with respect to a certain olefin polymer (A) (particularly when the olefin polymer (A) is a propylene polymer (a1)). Thereby, the number of tie molecules between lamellae and lamellae is reduced. When the number of tie molecules is small during stretching, the initial higher-order structure is uniformly deformed, and as a result, uniform stretchability is improved. From such a viewpoint, the melting endotherm (ΔH-D) is preferably 10 to 70 J / g, more preferably 20 to 60 J / g, and still more preferably 30 to 50 J / g.
The melting endotherm (ΔH−D) can be controlled by appropriately adjusting the monomer concentration and reaction pressure.
The melting endotherm (ΔH-D) is a melting endotherm curve obtained by DSC measurement with a line connecting a point on the low temperature side where there is no change in calorie and a point on the high temperature side where there is no change in calorie as a baseline. It is calculated by obtaining the area surrounded by the line portion including the peak and the base line.

(Molecular weight distribution (Mw / Mn))
The molecular weight distribution (Mw / Mn) of the olefin polymer (B) and the propylene polymer (b1) is preferably less than 3.0 from the viewpoint of high strength. If the molecular weight distribution (Mw / Mn) is less than 3.0, low molecular weight components that adversely affect stretchability and molded article physical properties, such as film physical properties (for example, mechanical properties and optical properties), are suppressed. The physical properties of the molded article of the invention, particularly the deterioration of the film physical properties of the stretched film, is suppressed. From such a viewpoint, the molecular weight distribution (Mw / Mn) of the olefin polymer (B) and the propylene polymer (b1) is preferably 2.5 or less, more preferably 1.5 to 2.5. .
In the present invention, the molecular weight distribution (Mw / Mn) is a value calculated from the polystyrene-equivalent weight average molecular weight Mw and number average molecular weight Mn measured by gel permeation chromatography (GPC).

The olefin polymer (B) and the propylene polymer (b1) of the present invention are preferably propylene polymers satisfying either one of the following (1) or (2) or both, and more preferably Satisfies the following (3), more preferably satisfies the following (4) and (5).
(1) [mmmm] is 20 to 60 mol%.
(2) Using a differential scanning calorimeter (DSC), hold the sample at −10 ° C. for 5 minutes in a nitrogen atmosphere, and then raise the temperature at 10 ° C./min. The melting point (Tm-D) defined as the observed peak top is 0-120 ° C.
(3) [rrrr] / (1- [mmmm]) ≦ 0.1
(4) [rmrm]> 2.5 mol%
(5) [mm] × [rr] / [mr] ² ≦ 2.0

(1) Mesopentad fraction [mmmm]
The mesopentad fraction [mmmm] is an index representing the stereoregularity of the olefin polymer (B) and the propylene polymer, and the stereoregularity increases as the mesopentad fraction [mmmm] increases.
When the olefin polymer (B) is a propylene homopolymer, the mesopentad fraction [mmmm] is improved in handling properties of the propylene polymer and stretchability when added in a small amount to the olefin polymer (A). From a viewpoint of an effect, Preferably it is 20-60 mol%, More preferably, it is 30-55 mol%, More preferably, it is 40-50 mol%. When the mesopentad fraction [mmmm] is 20 mol% or more, the stretchability can be improved without reducing the rigidity of the olefin polymer (A), which is the main component of the polyolefin composition of the present invention. If it is 60 mol% or less, it is not eutectic with the main component olefin polymer (A), and is compatible with the amorphous part of the main component olefin polymer (A) to be extensible. Can be improved.

(2) Melting point (Tm-D)
The melting point (Tm-D) of the olefin polymer (B) and the propylene polymer (b1) is preferably higher from the viewpoint of strength and moldability. Preferably it is 0-120 degreeC, More preferably, it is 50-100 degreeC, More preferably, it is 55-90 degreeC, More preferably, it is 60-80 degreeC.
In the present invention, a differential scanning calorimeter (DSC-7, manufactured by Perkin Elmer Co., Ltd.) is used, and 10 mg of a sample is held at −10 ° C. for 5 minutes in a nitrogen atmosphere and then heated at 10 ° C./min. The peak top of the peak observed on the highest temperature side of the melting endothermic curve obtained by the above is defined as the melting point (Tm-D). The melting point can be controlled by appropriately adjusting the monomer concentration and reaction pressure.

(3) [rrrr] / (1- [mmmm])
The value of [rrrr] / (1- [mmmm]) is obtained from the mesopentad fraction [mmmm] and the racemic pentad fraction [rrrr] and is an index indicating the uniformity of the regularity distribution of polypropylene. When this value of [rrrr] / (1- [mmmm]) is increased, it becomes a mixture of highly stereoregular polypropylene and atactic polypropylene like conventional polypropylene produced using an existing catalyst system, and the polypropylene is stretched after molding. It causes stickiness of the film. The unit of [rrrr] and [mmmm] in the above is mol%.
From the standpoint of stickiness, the value of [rrrr] / (1- [mmmm]) in the olefin polymer (B) and the propylene polymer (b1) is preferably 0.1 or less, more preferably 0.8. 001 to 0.05, more preferably 0.001 to 0.04, and particularly preferably 0.01 to 0.04.

Here, the mesopentad fraction [mmmm], the racemic pentad fraction [rrrr], and the racemic meso racemic meso pendad fraction [rmrm], which will be described later, are determined by A. Zambelli et al. According to “Macromolecules, 6, 925 (1973) ”, and meso fraction, racemic fraction, and racemic meso-racemic meso in pentad units in the polypropylene molecular chain measured by the methyl group signal of the ¹³ C-NMR spectrum. It is a fraction. As the mesopentad fraction [mmmm] increases, the stereoregularity increases. Further, triad fractions [mm], [rr] and [mr] described later are also calculated by the above method.

(4) Racemic meso racemic meso pentad fraction [rmrm]
The racemic meso racemic meso pentad fraction [rmrm] is an index representing the randomness of the stereoregularity of polypropylene, and the randomness of polypropylene increases as the value increases.
The racemic meso racemic meso pentad fraction [rmrm] of the olefin polymer (B) and the propylene polymer (b1) is preferably more than 2.5 mol%. When [rmrm] of the olefin polymer (B) and the propylene polymer (b1) exceeds 2.5 mol%, the randomness increases, and the olefin weight which is the main component of the polyolefin composition of the present invention. Copolymerization (A) (especially when the olefin polymer (A) is a propylene polymer (a1)) becomes difficult to eutectify, and as a result, a decrease in heat resistance and rigidity of the polyolefin composition is suppressed. The From such a viewpoint, the racemic meso racemic meso pentad fraction [rmrm] of the olefin polymer (B) and the propylene polymer (b1) is more preferably 2.6 mol% or more, and still more preferably 2. 7 mol% or more. The upper limit is usually preferably about 10 mol%, more preferably 7 mol%, still more preferably 5 mol%, and particularly preferably 4 mol%.

(5) [mm] × [rr] / [mr] ²
The value of [mm] × [rr] / [mr] ² calculated from the triad fraction [mm], [rr] and [mr] represents an index of randomness of the polymer. The olefin polymer (A) which is the main component of the polyolefin composition of the present invention (especially when the olefin polymer (A) is a propylene polymer (a1)) and eutectic crystallized. It does not occur, and the stretchability can be improved efficiently with respect to the main component olefin polymer (A) (particularly propylene polymer (a1)). In the olefin polymer (B) and the propylene polymer (b1) of the present invention, the value of the above formula is usually 2 or less, preferably 1.8 to 0.5, more preferably 1.5 to 0.5. It is a range. In addition, the unit of [mm] and [rr] in the above is mol%.

The propylene polymer (b1) can be produced, for example, using a metallocene catalyst as described in WO2003 / 087172. In particular, those using a transition metal compound in which a ligand forms a cross-linked structure via a cross-linking group are preferred, and in particular, a transition metal compound that forms a cross-linked structure via two cross-linking groups and Metallocene catalysts obtained by combining promoters are preferred.
For example,
(I) General formula (I)

[In the formula, M represents a group 3-10 of the periodic table or a lanthanoid series metal element, and E ¹ and E ² represent a substituted cyclopentadienyl group, an indenyl group, a substituted indenyl group, a heterocyclopentadienyl group, respectively. A ligand selected from a substituted heterocyclopentadienyl group, an amide group, a phosphide group, a hydrocarbon group, and a silicon-containing group, which forms a cross-linked structure via A ¹ and A ² In addition, they may be the same or different from each other, X represents a σ-bonded ligand, and when there are a plurality of X, the plurality of X may be the same or different, and other X, E ¹ , E ² or Y may be cross-linked. Y represents a Lewis base, and when there are a plurality of Y, the plurality of Y may be the same or different, and may be cross-linked with other Y, E ¹ , E ² or X, and A ¹ and A ² are A divalent bridging group that binds two ligands, a hydrocarbon group having 1 to 20 carbon atoms, a halogen-containing hydrocarbon group having 1 to 20 carbon atoms, a silicon-containing group, a germanium-containing group, a tin-containing group _{, -O -, - CO -,} - S -, - SO 2 -, - Se -, - NR 1 -, - PR 1 -, - P (O) R 1 -, - BR 1 - or -AlR ¹ - R ¹ represents a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, or a halogen-containing hydrocarbon group having 1 to 20 carbon atoms, which may be the same as or different from each other. q represents an integer of 1 to 5 and represents [(M valence) -2], and r represents an integer of 0 to 3. ]
And (ii) (ii-1) a compound capable of reacting with the transition metal compound of component (i) or a derivative thereof to form an ionic complex, and (ii-2) aluminoxane And a polymerization catalyst containing a component selected from:

  As the transition metal compound (i), a ligand is preferably a (1,2 ′) (2,1 ′) double-bridged transition metal compound, such as (1,2′-dimethylsilylene) ( 2,1'-dimethylsilylene) -bis (3-trimethylsilylmethylindenyl) zirconium dichloride.

  Specific examples of the compound of component (ii-1) include triethylammonium tetraphenylborate, tri-n-butylammonium tetraphenylborate, trimethylammonium tetraphenylborate, tetraethylammonium tetraphenylborate, methyl tetraphenylborate (tri- n-butyl) ammonium, benzyl tetraphenylborate (tri-n-butyl) ammonium, dimethyldiphenylammonium tetraphenylborate, triphenyl (methyl) ammonium tetraphenylborate, trimethylanilinium tetraphenylborate, methylpyridinium tetraphenylborate, tetra Benzylpyridinium phenylborate, methyl tetraphenylborate (2-cyanopyridinium), trikis (tetrafluorophenyl) borate triethyla Monium, tetrakis (pentafluorophenyl) tri-n-butylammonium borate, tetrakis (pentafluorophenyl) triphenylammonium borate, tetrakis (pentafluorophenyl) tetra-n-butylammonium borate, tetraethylammonium tetrakis (pentafluorophenyl) borate Benzyl tetrakis (pentafluorophenyl) ammonium borate (tri-n-butyl), methyldiphenylammonium tetrakis (pentafluorophenyl) borate, triphenyl (methyl) ammonium tetrakis (pentafluorophenyl) borate, tetrakis (pentafluorophenyl) boric acid Methylanilinium, tetrakis (pentafluorophenyl) borate dimethylanilinium, tetrakis (pentafluoropheny L) Trimethylanilinium borate, methyl pyridinium tetrakis (pentafluorophenyl) borate, benzyl pyridinium tetrakis (pentafluorophenyl) borate, methyl tetrakis (pentafluorophenyl) borate (2-cyanopyridinium), benzyl tetrakis (pentafluorophenyl) borate (2-cyanopyridinium), methyl tetrakis (pentafluorophenyl) borate (4-cyanopyridinium), triphenylphosphonium tetrakis (pentafluorophenyl) borate, tetrakis [bis (3,5-ditrifluoromethyl) phenyl] dimethylaniline borate Ferrocenium tetraphenylborate, silver tetraphenylborate, trityl tetraphenylborate, tetraphenylporphyrin manganese tetraphenylborate, Trakis (pentafluorophenyl) borate ferrocenium, tetrakis (pentafluorophenyl) borate (1,1′-dimethylferrocenium), tetrakis (pentafluorophenyl) decamethylferrocenium borate, tetrakis (pentafluorophenyl) silver borate, Tetrakis (pentafluorophenyl) triborate borate, tetrakis (pentafluorophenyl) lithium borate, tetrakis (pentafluorophenyl) sodium borate, tetrakis (pentafluorophenyl) borate Teolaphenylporphyrin manganese, silver tetrafluoroborate, silver hexafluorophosphate, hexa Examples thereof include silver fluoroarsenate, silver perchlorate, silver trifluoroacetate, and silver trifluoromethanesulfonate.

  Examples of the aluminoxane as the component (ii-2) include known chain aluminoxanes and cyclic aluminoxanes.

  Also, trimethylaluminum, triethylaluminum, triisopropylaluminum, triisobutylaluminum, dimethylaluminum chloride, diethylaluminum chloride, methylaluminum dichloride, ethylaluminum dichloride, dimethylaluminum fluoride, diisobutylaluminum hydride, diethylaluminum hydride, ethylaluminum sesquichloride, etc. The propylene-based polymer (b1) may be produced using a combination of these organoaluminum compounds.

<Additives>
A polyolefin-based composition suitable for the stretched film of the present invention is an antioxidant, a heat-resistant stabilizer, a weather-resistant stabilizer, an antistatic agent, a slip agent, if necessary, as long as the object of the present invention is not impaired. Antifogging agents, lubricants, nucleating agents, antiblocking agents, dyes, pigments, natural oils, synthetic oils, waxes, fillers, elastomers, and the like can be blended.
As the antioxidant, a hindered phenol-based, sulfur-based, lactone-based, organic phosphite-based, organic phosphonite-based antioxidant, or an antioxidant obtained by combining several of these can be used. The antioxidant is preferably blended in the range of 0.01 to 5% by mass with respect to 100% by mass of the total amount of the polyolefin-based composition.
As the antistatic agent, known low molecular type or high molecular type antistatic agents that are generally used can be suitably used.
Examples of the low molecular weight antistatic agent include nonionic antistatic agents such as alkyldiethanolamine, polyoxyethylene alkylamide, monoglycerin fatty acid ester, diglycerin fatty acid ester, sorbitan fatty acid ester, and tetraalkylammonium salt type cationic type. Antistatic agents such as antistatic agents, anionic antistatic agents such as alkylsulfonates, and amphoteric antistatic agents such as alkylbetaines.
Examples of polymer antistatic agents include nonionic antistatic agents such as polyetheresteramide, anionic antistatic agents such as polystyrene sulfonic acid, and cationic antistatic agents such as quaternary ammonium salt-containing polymers. Etc.
The antistatic agent is preferably blended in the range of 0.01 to 5% by mass with respect to 100% by mass of the total amount of the polyolefin-based composition.
As the slip agent, amides of saturated or unsaturated fatty acids such as lauric acid, palmitic acid, oleic acid, stearic acid, erucic acid and hebenic acid, or bisamides of these saturated or unsaturated fatty acids can be used. Of these, erucic acid amide and ethylenebisstearic acid amide are preferable. The slip agent is preferably blended in the range of 0.01 to 5% by mass with respect to 100% by mass of the total amount of the polyolefin-based composition.
Antiblocking agents include finely divided silica, finely divided aluminum oxide, finely divided clay, powdered or liquid silicone resin, polytetrafluoroethylene resin, finely crosslinked resin such as crosslinked acrylic resin or methacrylic resin powder Can be mentioned. Of these, finely divided silica and finely powdered crosslinked resin are preferred. It is preferable to mix | blend an antiblocking agent in 0.01-5 mass% with respect to 100 mass% of whole quantity of the said polyolefin-type composition.
As the elastomer, styrene-based, olefin-based, ester-based, soft vinyl chloride-based, urethane-based, amide-based, butadiene-isoprene-based elastomers, or an elastomer obtained by combining several of these can be used. Of these, styrene, olefin, and butadiene / isoprene are preferred. The elastomer is preferably blended in the range of 1 to 20% by mass with respect to 100% by mass of the total amount of the polyolefin-based composition.

<Manufacture of polyolefin-based composition>
The polyolefin-based composition of the present invention is prepared by adding the above components (a) and (b) and additives as necessary, for example, a high-speed mixer, a Banbury mixer, a continuous kneader, a single screw or a twin screw extruder. In general, a method of granulating by heating, melting and kneading using an ordinary mixing and kneading machine such as a roll or a Brabender plastograph is employed.
The polyolefin-based composition of the present invention is preferably used for extrusion molding. Further, the above components (a) and (b) may be used (dry blending) immediately before extrusion molding, for example, simultaneously in a hopper on an extruder.

[Molded body]
The molded object of this invention is a molded object which consists of said polyolefin type composition.
The polyolefin-based composition is suitably used for a molding method having a stretching process. For example, a beneficial effect can be expected when used for blow molding including extrusion blow molding or injection blow molding, or thermoforming, or film molding described later.
For example, the blow molded article can be produced by blow molding the polyolefin-based composition of the present invention using a known blow molding apparatus under known conditions. That is, the polyolefin-based composition of the present invention is heated and melted in an extruder and extruded into a tube shape. After being sandwiched in a mold carved only on the outside of the product, air is drawn into (injected into) the tube. Can be used in a molding method in which a hollow body is formed by inflating a shaped body along a mold wall surface. The excellent stretchability of the polyolefin-based composition of the present invention can reduce the thickness unevenness (variation) of the formed hollow body bottle and make it uniform, so that the mechanical properties of the bottle (for example, strength, etc.) ) Is also suppressed, and transparency is improved. Therefore, for example, when a propylene polymer is used as the polyolefin composition, it can be applied to a polypropylene injection stretch blow bottle instead of a polyethylene terephthalate (PET) bottle.
Moreover, the melt-kneaded material of the polyolefin-type composition of this invention can be made into the resin particle of predetermined size, and a foaming molding can be manufactured. For example, a dispersion in which resin particles of a predetermined size made of a melt-kneaded product of the polyolefin composition of the present invention are dispersed in water in a pressure resistant container together with a volatile foaming agent is prepared. The resin particles are heated to a temperature in the range of melting point-20 ° C. to melting point + 20 ° C. of the polyolefin-based composition, and the resin particles are impregnated with a volatile foaming agent. Then, while maintaining the temperature and pressure in the pressure vessel constant by pressurizing the vapor pressure of the volatile foaming agent, the dispersion of the resin particles made of the polyolefin-based composition and water is placed in the pressure vessel. And a method of releasing in a lower pressure atmosphere. By using the polyolefin-based composition of the present invention, the stretchability at the time of foaming is improved, so that a foamed molded article having good surface elongation and good mold transferability can be obtained.
Moreover, the film mentioned later can be manufactured by extrusion-molding the polyolefin-type composition of this invention.

<Film>
The film of the present invention is a film made of the above polyolefin-based composition. The film can be produced, for example, by extruding the film from a known mold (die) under known conditions using the polyolefin composition. For example, it can be obtained by cooling a film comprising the polyolefin-based composition of the present invention obtained by extrusion molding with a chill roll. The film comprising the polyolefin composition of the present invention has good transparency and gloss.
Moreover, the said film is used suitably also for a foam film, a filler compounded film, etc. As a filler mix | blended with the said filler compounded film, well-known fillers, such as a talc, mica, a calcium carbonate, magnesium carbonate, a silica, glass, are employable.
The thickness of the film of the present invention is not particularly limited as long as the stretched film thickness is 30 μm or more and 400 μm or less, but it is 40 μm or more, preferably 100 μm or more, and 5000 μm or less, preferably 3000 μm or less. More preferably, it is 2000 μm or less.
In some cases, when the thickness of the film of the present invention exceeds 250 μm, the film may be referred to as a “sheet”.

<Stretched film>
The stretched film of the present invention is a stretched film including the polyolefin-based composition of the present invention and oriented in at least one direction, preferably a stretched film oriented in a uniaxial or biaxial direction. Preferred examples of the stretched film include a polyethylene stretched film, a polypropylene stretched film, and a polybutene stretched film, but a polypropylene stretched film is more preferred because of having excellent stretched film properties.
In addition, the kind of this stretched film is determined by the kind of the olefin polymer (A) which is a base resin of the stretched film and is also a main component of the polyolefin composition.
The stretched film of the present invention has a thickness of 30 μm or more, preferably 40 μm or more, and 400 μm or less, preferably 250 μm or less, more preferably 80 μm or less.
By using the polyolefin-based composition of the present invention, thickness unevenness can be suppressed even in a stretched film having a large film thickness.
In some cases, when the thickness of the stretched film of the present invention exceeds 250 μm, the stretched film may be referred to as a “stretched sheet”.
There are two methods for increasing the thickness of the stretched film. One is a method in which the film / sheet thickness obtained from the T-die by extrusion molding is a normal thickness, and the draw ratio is lowered. Second, there is a method in which the film / sheet obtained from the T die is made thicker than usual and the draw ratio is not changed. In the former, stretching unevenness (thickness unevenness) due to undrawn (necking) is likely to occur, and it is difficult to obtain a target sheet thickness. Even if stretching unevenness does not occur, the strength of the film is lowered, so that the elastic modulus may be a problem. On the other hand, in the latter case, since the sheet before stretching at the time of stretching becomes thick, even when preheating at the time of stretching is insufficient or even when preheating is sufficient, stress at the time of stretching is required. Therefore, stretchability deteriorates, stretching unevenness due to undrawn (necking) occurs, and only a film having stretching unevenness (thickness unevenness) can be obtained.
By using the polyolefin composition of the present invention, the problem can be solved in either case. For the first, when the polyolefin polymer (B) is blended with the polyolefin polymer (A), the growth of spherulite size is suppressed due to the slow crystallinity while maintaining the melting point, Spherulite size decreases. Furthermore, when the spherulite occupation area ratio decreases, the neck deformation of the initial deformation is suppressed and the uniform stretchability is improved. The effect is expressed by the same mechanism for the second. In addition, when the polyolefin polymer (B) enters the amorphous phase of the polyolefin polymer (A), the long period of the lamellar structure increases and the thickness of the crystalline phase of the lamellar structure does not change greatly. The crystallinity is also reduced by increasing the thickness of the amorphous phase. Therefore, since the initial stress at the time of stretching (the force for breaking the spherulites) is reduced, it is presumed that uniform and easy stretching can be realized even if the film is thick.

<Multilayer film>
The multilayer film of the present invention is a multilayer film composed of two or more layers, and at least one layer contains the polyolefin-based composition. The multilayer film can be produced by, for example, extruding from a known mold (die) with a known condition using the polyolefin-based composition. For example, it can be obtained by cooling a multilayer film comprising the polyolefin-based composition of the present invention obtained by extrusion molding with a chill roll.
The thickness of the multilayer film of the present invention is not particularly limited as long as the thickness of the stretched multilayer film composed of the polyolefin-based composition is 30 μm or more and 400 μm or less, but the thickness of the multilayer film is not particularly limited, but 40 μm or more, preferably 100 μm. And not more than 5000 μm, preferably not more than 3000 μm, more preferably not more than 2000 μm.
In some cases, when the thickness of the multilayer film of the present invention exceeds 250 μm, the multilayer film may be referred to as a “multilayer sheet”.

<Stretched multilayer film>
The stretched multilayer film of the present invention is a stretched multilayer film composed of two or more layers, wherein at least one layer contains the polyolefin-based composition of the present invention, and the layer or the multilayer including the layer is at least in one direction. It is an oriented stretched multilayer film. A stretched multilayer film oriented in a uniaxial or biaxial direction is preferable. Further, in the stretched multilayer film, a layer made of a resin composition that functions as a sealant layer and a skin layer may be laminated on a layer adjacent to the layer made of the polyolefin-based composition. Moreover, when the layer which consists of the said polyolefin-type composition turns into an outermost layer, you may function as a heat seal layer.
When the outermost layer is a heat seal layer, a layer made of the olefin polymer (A) described above is preferable. For example, the olefin polymer (A) is a propylene-ethylene random copolymer, propylene-butene random copolymer. More preferably, it is a coalescence or propylene-α-olefin random copolymer.
In addition, the stretched multilayer film of the present invention can be used by appropriately selecting a resin composition as another layer of the outermost layer and the inner layer depending on the application. For example, in addition to the polyolefin-based composition, a gas barrier can be used. Resin (ethylene-vinyl alcohol copolymer, etc.) having a property, and resin (nylon, etc.) having rigidity.
The thickness of the layer composed of the polyolefin-based composition of the stretched multilayer film of the present invention is 30 μm or more, preferably 40 μm or more, and 400 μm or less, preferably 250 μm or less, more preferably 80 μm or less. When the thickness of the stretched multilayer film of the present invention exceeds 250 μm, the stretched multilayer film may be referred to as a “stretched multilayer sheet”.

  In the stretched film of the present invention, the film comprising the polyolefin-based composition, the stretched film, the multilayer film, and the stretched multilayer film when the propylene polymer (b1) is a main component are described later in Examples. In addition, it is superior to conventional polypropylene films, stretched films, multilayer films, and stretched multilayer films that use polypropylene raw materials, and production line speeds can be increased, and the frequency of breakage is reduced compared to conventional methods. In addition, the mechanical properties and optical properties of the obtained films are excellent.

  The haze value (as 20 μm) representing the transparency of the film, stretched film, or stretched multilayer film of the present invention is preferably 1.2 or less, more preferably 1.0 or less, and a gloss (gross) representing optical properties is 130. % Or more, more preferably 135% or more.

[Method for producing stretched film]
The method for producing a stretched film of the present invention is a method for producing a stretched film by reheating a film containing one or more layers containing the polyolefin-based composition of the present invention and simultaneously or sequentially stretching in a uniaxial or biaxial direction. It is.
Below, an example is demonstrated as a general manufacturing method of the stretched film of this invention. In addition, in this invention, it does not restrict to the following manufacturing methods.
The polyolefin-based composition is melt-extruded and dropped from a T-shaped die in a curtain shape, and immediately after this, the molten film is solidified by a cooling roll to obtain a primary film. Subsequently, stretching is performed by a subsequent stretching apparatus. In addition, the preferable resin temperature at the time of the said melt extrusion is 180-300 degreeC, More preferably, it is 200-280 degreeC. Further, the cooling roll temperature is preferably 0 to 120 ° C, more preferably 10 to 100 ° C.
The primary film obtained by extrusion can be further stretched by uniaxial stretching or biaxial stretching to obtain a stretched stretched film. Examples of the stretching method include a method in which the extruded primary film is continuously subjected to sequential biaxial stretching and simultaneous biaxial stretching by a tenter method, or a method in which simultaneous biaxial stretching is performed by an inflation method. A batch-type biaxial stretching apparatus may be used. Although a draw ratio can be suitably determined according to the use of a stretched film, it is uniaxially stretched or biaxially stretched 2 to 12 times in the machine direction (MD) and / or the direction perpendicular to the machine direction (TD). It is preferable to do.
In general, when sequential biaxial stretching is performed, for example, when the film is first oriented by stretching in the MD direction and then stretched in the TD direction, the stretching ratio in the MD direction is high. If it is too high, it is known that when the draw ratio in the TD direction is increased, a problem that the film is easily broken occurs. When the polyolefin-based composition of the present invention is used, good stretchability can be obtained, so that molding at a high stretch ratio is possible. For example, after setting an appropriate stretching temperature, it is 4 times in the MD direction. As described above, the film can be stretched by 5 times or more, and after stretching in the MD direction, it can be stretched by 9 times or more, and further 9.5 times or more in the TD direction.
In sequential biaxial stretching by the tenter method, first, the primary film is reheated to a temperature suitable for stretching (longitudinal (MD) stretching temperature; preferably 70 to 180 ° C., more preferably 80 to 170 ° C.), Stretching in the machine direction (MD) between a slow roll (front roll) and a fast roll (rear roll). Next, while maintaining both ends of the film stretched in the MD direction in the tenter part, the film is further heated (transverse (TD) stretching temperature; preferably 140 to 175 ° C, more preferably 145 to 170 ° C), and the machine direction Is stretched in the vertical direction (TD). Finally, the film after the stretching treatment is heat treated (heat setting temperature; preferably 140 to 175 ° C., more preferably 145 to 170 ° C.) to stabilize the properties of the stretched film, and the film is wound up by a winder, A desired stretched film can be obtained. The obtained stretched film may be further adjusted to an appropriate width and length with a machine such as a slitter to have a shape according to the purpose. The stretched film of the present invention can also be obtained by using a biaxial simultaneous tenter-type stretching method in which stretching in the machine direction (MD) and the vertical direction (TD) as described above is performed simultaneously.
In addition, from the viewpoint of further improving the transparency of the obtained stretched film, the MD stretching temperature and the TD stretching temperature are preferably low temperature conditions among preferable conditions.

  Further, as the draw ratio, the machine direction (MD) and / or the surface ratio obtained by multiplying the machine direction (TD) by the perpendicular direction (TD) is usually 4 to 50 times, but the polyolefin composition of the present invention. When is used, the stretchability is further improved, so that stretching at a high magnification becomes possible. For example, stretching at a surface magnification of 47 times or more is possible, and furthermore, stretching at a higher magnification is possible than the range of 4 to 50 times, for example, 50.5 times or more, and further 55 times or more. Stretching is possible even at a surface magnification. Thus, even if the film stretched | stretched at high magnification is thick, it is excellent in transparency, and it is possible to suppress shrinkage | contraction of the film after extending | stretching.

[Method for producing stretched multilayer film]
Moreover, the manufacturing method similar to the manufacturing method of the said stretched film can be used also about the manufacturing method of the stretched multilayer film of this invention. That is, it contains at least one layer containing the polyolefin-based composition of the present invention, is laminated with a layer made of another resin composition, and the primary film obtained by extrusion is further uniaxially laminated in the same manner as in the method for producing the stretched film. A stretched multilayer film may be obtained by stretching or stretching by biaxial stretching or the like, or the extruded primary film is continuously continuous biaxially or simultaneously biaxially stretched by a tenter method, or It can be produced by performing simultaneous biaxial stretching by an inflation method. In the above-described extrusion process in the case of obtaining a primary film, for example, each layer of resin (or resin composition) is supplied from two or more different extruders, laminated inside a T-shaped die, and co-extruded. By doing so, the primary film can be obtained.

Further, among the stretched films in the present invention, the method for producing a polypropylene stretched film includes the propylene polymer (b1) (particularly, the propylene homopolymer having the above-mentioned melting endotherm (ΔH-D) and having the above-described characteristics. ) Is preferably 0.5% by mass or more and less than 50% by mass, more preferably 0.5% by mass or more and less than 20% by mass, still more preferably 0.5% by mass or more and less than 15% by mass, or more. More preferably, it is a manufacturing method which manufactures at 1 mass% or more and less than 10 mass%.
On the other hand, the propylene-based polymer (b1) (particularly, the propylene homopolymer having the melting endotherm (ΔH-D) and having the above-mentioned characteristics) has a uniform composition and a narrow molecular weight distribution, so it can be pelletized even at room temperature Can be treated as Therefore, a film can be formed even when the propylene polymer (b1) is dry blended with the olefin polymer (A).

[Packaging materials]
The polyolefin-based composition of the present invention is suitably used for packaging materials. The molded body, film, stretched film, or stretched multilayer film comprising the polyolefin-based composition of the present invention is not particularly limited. For example, the packaging material for food use or industrial use, for example, fresh food, processed food , Materials that can be used to wrap and pack cooked products, retort foods, confectionery, beverages, etc. directly or indirectly (eg confectionery boxes), cigarette cases, pharmaceuticals, electrical components such as capacitors and capacitors, textiles, Materials that can be used for packaging and packaging of stationery, miscellaneous goods, plastic parts, metal parts, etc., or electrical parts such as capacitors and capacitors themselves, fibers, stationery, plastic parts, various reusable containers, laboratory equipment, speaker cones It can be used for a wide range of applications such as automobile parts or banknotes. As for the method of use, the film may be used as it is, may be used by being laminated with another film, or may be used after metal deposition.
Moreover, it can be used also for the flat yarn used as the flat tape (thread | yarn) which gave the intensity | strength by cutting a film into a strip shape (slit), and making it a uniaxially stretched film.
It can also be used as a protective film, synthetic paper, label, and seal substrate, and can be used for film synthetic paper, fiber synthetic paper, and film laminate synthetic paper.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.

Below, the measuring method of the olefin polymer (A) used in the Example and an olefin polymer (B) is demonstrated.
[DSC measurement]
Using a differential scanning calorimeter (DSC-7, manufactured by Perkin Elmer Co.), a melting endotherm obtained by holding 10 mg of a sample at −10 ° C. for 5 minutes in a nitrogen atmosphere and then raising the temperature at 10 ° C./min. It calculated | required as melting endotherm (DELTA) HD from a curve. Moreover, melting | fusing point (Tm-D) was calculated | required from the peak top of the peak observed on the highest temperature side of the obtained melting endothermic curve.
The melting endotherm (ΔH-D) is a differential scanning calorimeter (manufactured by Perkin Elmer Co., Ltd.) with a line connecting a point on the low temperature side where there is no change in heat quantity and a point on the high temperature side where there is no change in heat quantity as the baseline. , DSC-7), and calculating the area surrounded by the line portion including the peak of the melting endothermic curve obtained by DSC measurement and the base line.

[Weight average molecular weight (Mw), molecular weight distribution (Mw / Mn) measurement]
The weight average molecular weight (Mw) and the number average molecular weight (Mn) were measured by gel permeation chromatography (GPC) method to determine the molecular weight distribution (Mw / Mn). For the measurement, the following equipment and conditions were used, and polystyrene-reduced weight average molecular weight and number average molecular weight were obtained. The molecular weight distribution (Mw / Mn) is a value calculated from these weight average molecular weight (Mw) and number average molecular weight (Mn).
<GPC measurement device>
Column: “TOSO GMHHR-H (S) HT” manufactured by Tosoh Corporation
Detector: RI detection for liquid chromatogram "WATERS 150C" manufactured by Waters Corporation
<Measurement conditions>
Solvent: 1,2,4-trichlorobenzene Measurement temperature: 145 ° C
Flow rate: 1.0 ml / min Sample concentration: 2.2 mg / ml
Injection volume: 160 μl
Calibration curve: Universal Calibration
Analysis program: HT-GPC (Ver.1.0)

[NMR measurement]
The ¹³ C-NMR spectrum was measured with the following apparatus and conditions. In addition, the attribution of the peak followed the method proposed by A. Zambelli et al. In “Macromolecules, 8, 687 (1975)”.
Apparatus: JNM-EX400 type ¹³ C-NMR apparatus manufactured by JEOL Ltd. Method: Proton complete decoupling method Concentration: 220 mg / ml
Solvent: 90:10 (volume ratio) mixed solvent of 1,2,4-trichlorobenzene and heavy benzene Temperature: 130 ° C
Pulse width: 45 °
Pulse repetition time: 4 seconds Integration: 10,000 times

<Calculation formula>
M = m / S × 100
R = γ / S × 100
S = Pββ + Pαβ + Pαγ
S: Signal intensity of side chain methyl carbon atoms of all propylene units Pββ: 19.8 to 22.5 ppm
Pαβ: 18.0 to 17.5 ppm
Pαγ: 17.5 to 17.1 ppm
γ: Racemic pentad chain: 20.7 to 20.3 ppm
m: Mesopentad chain: 21.7-22.5 ppm

The mesopentad fraction [mmmm], the racemic pentad fraction [rrrr] and the racemic meso racemic meso pendad fraction [rmrm] are described in “Macromolecules, 6, 925 (1973)” by A. Zambelli et al. are those determined in conformity with the proposed method, meso fraction in pentad units in the polypropylene molecular chain as measured by the signal of the methyl groups of the ^{13 C-NMR} spectrum, the racemic fraction and the racemic meso racemic meso It is a fraction. As the mesopentad fraction [mmmm] increases, the stereoregularity increases. The triad fractions [mm], [rr] and [mr] were also calculated by the above method.

[Melt flow rate (MFR) measurement]
Based on JIS K7210, the measurement was performed under conditions of a temperature of 230 ° C. and a load of 2.16 kg.

  The olefin polymer (A) used in the examples will be described below.

<Olefin polymer A>
As the olefin polymer (A),
“F-300SP” (PP resin manufactured by Prime Polymer Co., Ltd., melting point (Tm-D): 163 ° C., tensile elastic modulus: 1700 MPa, stereoregularity [mmmm]: 90%, heat of fusion (ΔH-D): 86 J / g )
Was used.

  Below, the manufacture example of the olefin polymer (B) used in the Example is demonstrated.

Production Example 1 [Production of Olefin Polymer (B)]
In a stainless steel reactor having an internal volume of 20 L with a stirrer, n-heptane was 20 L / hr, triisobutylaluminum was 15 mmol / hr, dimethylanilinium tetrakispentafluorophenylborate, and (1,2'-dimethylsilylene) A catalyst component obtained by contacting (2,1′-dimethylsilylene) -bis (3-trimethylsilylmethylindenyl) zirconium dichloride, triisobutylaluminum and propylene in a mass ratio of 1: 2: 20 in advance is used as zirconium. It was continuously supplied at a conversion of 6 μmol / hr.
Propylene and hydrogen were continuously supplied so as to keep the total pressure in the reactor at 1.0 MPa · G, and the polymerization temperature was appropriately adjusted to obtain a polymerization solution having a desired molecular weight.
An olefin polymer (B) was obtained by adding antioxidant to the obtained polymerization solution so that the content rate might become 1000 mass ppm, and then removing n-heptane which is a solvent.

  The olefin polymer (B) obtained in Production Example 1 was measured as described above. The results are shown in Table 1 below.

<Evaluation of biaxially stretched film>
The physical properties of the biaxially stretched films prepared in Examples and Comparative Examples described later were evaluated by the following measurement methods.

(Measuring mechanical properties)
Tensile speed with a tensile tester (manufactured by Shimadzu Corp., “Autograph AG-I”) using a strip-shaped test piece of 200 mm × 15 mm collected from each of the MD direction and TD direction of the produced biaxially stretched film Tensile at 300 mm / min, elastic modulus, breaking strength and breaking elongation were determined.
In each test, measurements were taken 5 times in the MD direction and 5 times in the TD direction, and the average value was taken as the measurement value. In addition, the test piece of MD direction means here the test piece whose longitudinal direction of the said strip-shaped test piece is MD direction of a biaxially stretched film. The same applies to the TD direction.
(I) Elastic modulus Using a strip-shaped test piece of 200 mm × 15 mm, a tensile tester was used to pull at a chuck-to-chuck distance of 150 mm and a pulling speed of 300 mm / min. A relation line (curve) was drawn on the two-dimensional coordinate axis, and the inclination of the relation line before the yield point was obtained as “elastic modulus”. The higher the modulus of elasticity, the better the rigidity of the film.

(Measurement of optical properties)
(I) Transparency (Haze) Measurement Based on JIS K7105 and JIS K7136, measurement was performed using “ISO Haze Meter (NDH2000)” manufactured by Nippon Denshoku Industries Co., Ltd. In addition, transparency is so high that a haze value is small.
Haze (%) = Td / Tt × 100
(Where, Td: diffuse transmittance, Tt: total light transmittance)
Moreover, in order to relieve the difference in haze due to the thickness of the film, the film thickness at 200 μm thickness was converted using the following formula.
Haze (as 200 μm) = Haze (%) × 200 μm (μm) / film thickness (μm)
Moreover, in order to relieve the difference in haze due to the thickness of the film, the film thickness at 50 μm thickness was converted using the following formula.
Haze (as 50 μm) = Haze (%) × 50 μm (μm) / film thickness (μm)
(Ii) Measurement of gloss (gloss) Based on JIS K7105 and JIS Z8741, it measured using the gloss meter "VG2000" by Nippon Denshoku Industries Co., Ltd. The 60-degree specular gloss was measured. Further, the higher the gloss value, the higher the glossiness.

[Measurement of heat shrinkage]
(JIS Z 1712 compliant, ISO 11501 compliant)
A 120 mm × 120 mm test piece sampled from the center of the produced biaxially stretched film was cut out and marked in the MD and TD directions on each side of the test piece. _Marked lines with an interval of 100 mm centered on the central part of each test piece (L _Md0, L _Td0 ), respectively.
The test piece was placed horizontally in an air circulation thermostat kept at a temperature of 120 ° C., heated for 15 minutes, and then taken out. Then, after cooling at room temperature for 30 minutes, the distance between marked lines ( _{LMd, LTd} ) was measured using calipers. The average value of the measured values of the three test pieces was determined, and the heat shrinkage (MD, TD) was determined by the following equation.
_{S MD = (L Md0 -L Md} / L Md0) × 100
Here, S: Heat shrinkage rate (%), L _Md0 : Distance between marked lines before heating (mm), L _Md : Distance between marked lines after heating (mm).
S _TD = (L _Td0 −L _Td / L _Td0 ) × 100
Here, S: Heat shrinkage rate (%), L _Td0 : Distance between marked lines before heating (mm), L _Td : Distance between marked lines after heating (mm).

(i) Thickness distribution measurement The thickness of the film was measured with a thickness distribution meter ("Millimar C1216" manufactured by Marl). The measurement range was 5 points at 5 cm intervals in the MD direction of the film, 18 points at 2 cm intervals in each example shown in Table 2 below in the TD direction, and 20 points at 5 cm intervals in each example shown in Table 3. A value obtained by calculating an average value from the obtained measured values was defined as a film thickness. The standard deviation was calculated from the measured values.
(ii) Thickness distribution uniformity The thickness distribution uniformity was evaluated using the following formula. A smaller value of I derived from the following formula indicates that the thickness distribution is more uniform. Less than 2% was marked with ◯, and 2% or more was marked with x.
Standard deviation (μm) / average thickness (μm) × 100 = I (%)

Example 1
A dry blend of a resin composition comprising 3% by weight of the olefin polymer (B) of Production Example 1 and 97% by weight of an olefin polymer (A) (PP, manufactured by Prime Polymer Co., Ltd., F-300SP, melting point: 163 ° C.) While the product was extruded at 250 ° C. with a 50 mm sheet molding machine manufactured by Thermo Plastics, a single layer film having a thickness of 1000 μm was produced. At this time, the temperature of the cooling roll was 50 ° C. The obtained monolayer film sheet was stretched in the machine direction (MD, longitudinal stretching) by a roll stretching machine manufactured by Iwamoto Seisakusho under the conditions of stretching temperature: 152 ° C. and longitudinal stretching ratio: 5 times to obtain a uniaxially stretched film. . The thickness unevenness and optical characteristics of the obtained film were evaluated. The results are shown in Table 2.

Comparative Example 1
The same procedure as in Example 1 was conducted except that the resin composition of Example 1 was changed to 100% of the olefin polymer (A). The thickness unevenness and optical characteristics of the obtained film were evaluated. The results are shown in Table 2.

  As can be seen from Table 2, the uniaxially stretched film containing the olefin polymer (B) has high film uniformity. It is considered that this is because the pre-heating is performed uniformly by increasing the adhesion to the roll during longitudinal stretching, and the roll transferability is good during stretching. By becoming uniform, the haze was improved and a transparent film was obtained.

Example 2
A dry blend of a resin composition comprising 3% by weight of the olefin polymer (B) of Production Example 1 and 97% by weight of an olefin polymer (A) (PP, manufactured by Prime Polymer Co., Ltd., F-300SP, melting point: 163 ° C.) The thing was implemented by the following method. The film was formed on a continuous molding pilot line manufactured by MHI.
A monolithic film by cooling a polyolefin composition with a chill roll while extruding a molten resin with an MHI continuous molding pilot machine (extruder screw system: 120 mmφ, extruder screw rotation speed: 67 rpm, tenter line speed: 200 m / min) At this time, the chill roll temperature was 25 ° C. and the raw fabric cooling water bath temperature was 30 ° C. The produced single-layer film was subsequently preheated with a preheating roll and then stretched at 137 ° C. and stretched. Magnification: stretched in the machine direction under the condition of 4.4 times (MD, longitudinal stretching), and further passed through a tenter with both ends of the film fixed by a chuck, stretching temperature: 153 ° C. and stretching ratio: 9.0 times The film was stretched in the direction perpendicular to the machine direction (TD, transverse stretching) at a heat setting temperature of 165 ° C. to produce a biaxially stretched film.

Comparative Example 2
The resin composition of Example 2 is 100% olefin polymer (A), stretched in the machine direction at a stretching temperature of 140 ° C. (MD, longitudinal stretching), and perpendicular to the machine direction at a stretching temperature of 157 ° C. The same procedure as in Example 2 was performed except that the film was stretched to TD and transverse stretching. The thickness unevenness and optical characteristics of the obtained film were evaluated. The results are shown in Table 3.

  As can be seen from Table 3, the biaxially stretched film containing the olefin polymer (B) has high film uniformity (that is, thickness unevenness is suppressed). This is considered to be because the adhesiveness to the roll is increased during the longitudinal stretching, the preheating is performed uniformly, and the roll transferability is good during the stretching. Furthermore, the addition of the olefin polymer (B) during transverse stretching makes it easier for heat to be transferred to the biaxially stretched film, which is considered to be a result of uniform film formation. Moreover, the biaxially stretched film containing the olefin polymer (B) was almost equal to the elastic modulus of the biaxially stretched film produced only with the olefin polymer (A), and the film uniformity could be improved. .

  The polyolefin-based composition of the present invention is excellent in heat resistance and excellent in mechanical properties and optical properties after stretching, so that it is a packaging material for food use, industrial use, etc., for example, fresh food, processed food, cooked product, retort Materials, cigarette cases, pharmaceuticals, electrical parts such as capacitors and capacitors, textiles, stationery, miscellaneous goods, plastic parts that can be used for packaging and packing food, confectionery, or beverages directly or indirectly (for example, candy boxes) , Materials that can be used for packaging and packaging, such as metal parts, or electrical parts such as capacitors and capacitors, textiles, stationery, plastic parts, various reusable containers, laboratory equipment, speaker cones, automotive parts, or banknotes It can be used for a wide range of applications. Moreover, it can be used also for the flat yarn used as the flat tape (thread | yarn) which gave the intensity | strength by cutting a film into a strip shape (slit), and making it a uniaxially stretched film. It can also be used as a protective film, synthetic paper, label, and seal substrate, and can be used for film synthetic paper, fiber synthetic paper, and film laminate synthetic paper.

Claims (11)

A stretched film comprising at least one layer comprising a polyolefin-based composition containing the following components (a) and (b), wherein the thickness of the layer is from 30 μm to 400 μm.
(A) Using a differential scanning calorimeter (DSC), hold the sample at −10 ° C. for 5 minutes in a nitrogen atmosphere, and then raise the temperature at 10 ° C./min. Olefin polymer (A) whose melting point (Tm-D) defined as the observed peak top exceeds 120 ° C
(B) Using a differential scanning calorimeter (DSC), the sample was held at −10 ° C. for 5 minutes in a nitrogen atmosphere, and then heated at 10 ° C./min. Olefin polymer (B) having a calorific value (ΔH-D) of 0 to 80 J / g and a molecular weight distribution (Mw / Mn) of less than 3.0   The said (b) component of the said polyolefin-type composition is 0.5 mass% or more and less than 50 mass% with respect to 100 mass% of total amounts with the said (a) and (b) component. Stretched film.   The stretched film according to claim 1 or 2, wherein the olefin polymer (A) is a propylene polymer (a1).   The stretched film according to any one of claims 1 to 3, wherein 50 mol% or more of the olefin polymer (B) is a propylene polymer (b1) composed of a propylene monomer. The stretched film according to claim 4, wherein the propylene-based polymer (b1) satisfies the following (i) and / or (ii).
(I) The structural unit of ethylene is contained in excess of 0 mol% and 20 mol% or less.
(Ii) The structural unit of 1-butene is contained in an amount exceeding 0 mol% and not more than 30 mol%. The stretched film according to claim 4, wherein the propylene polymer (b1) satisfies the following (1).
(1) [mmmm] is 20 to 60 mol% The stretched film according to any one of claims 4 to 6, wherein the propylene polymer (b1) satisfies the following (2).
(2) Using a differential scanning calorimeter (DSC), hold the sample at −10 ° C. for 5 minutes in a nitrogen atmosphere, and then raise the temperature at 10 ° C./min. The melting point (Tm-D) defined as the observed peak top is 0-120 ° C. The stretched film according to claim 6, wherein the propylene polymer (b1) satisfies the following (2) and (3).
(2) Using a differential scanning calorimeter (DSC), hold the sample at −10 ° C. for 5 minutes in a nitrogen atmosphere, and then raise the temperature at 10 ° C./min. The melting point (Tm-D) defined as the observed peak top is 0-120 ° C.
(3) [rrrr] / (1- [mmmm]) ≦ 0.1 The stretched film according to claim 6 or 8, wherein the propylene polymer (b1) satisfies the following (4) and (5).
(4) [rmrm]> 2.5 mol%
(5) [mm] × [rr] / [mr] ² ≦ 2.0   A film comprising one or more layers comprising the polyolefin-based composition according to any one of claims 1 to 9 is stretched simultaneously or sequentially in a uniaxial or biaxial direction so that the thickness of the layer is 30 µm or more and 400 µm or less. A method for producing a stretched film.   The packaging material which consists of a stretched film of any one of Claims 1-9.