JP2016107497A - Film, method for producing stretched film and packaging material using the film - Google Patents

Abstract

A multilayer film having a layer containing a crystalline resin having a relatively low melting point, the fracture is suppressed even when biaxially stretched, and mechanical properties (for example, elastic modulus) and optical properties (for example, haze, Provide a film having excellent gloss. The melting point includes a layer A having a melting point (Tm-D) of 80 ° C. or more and 155 ° C. or less, and an olefin polymer (I) having a melting endotherm (ΔH-D) of 0 to 80 J / g. (Tm-D) is a film containing B layer exceeding 155 degreeC. [Selection figure] None

Description

  The present invention relates to a film, a method for producing a stretched film, and a packaging material using the film.

Among the films obtained by uniaxially or biaxially stretching a multilayer film, a polypropylene biaxially stretched multilayer film is known.
In addition, as the polypropylene biaxially stretched multi-layer film, for example, a biaxially stretched multi-layer film having a heat-sealing property by including a component having a low melting point in the outermost layer, a matt tone or a hologram tone by embossing, etc. Are known.

For example, as a biaxially stretched film, Patent Document 1 includes a crystalline polypropylene layer and a crystalline ethylene propylene copolymer layer having an ethylene content of 1.0 to 6.0% by weight and a randomness index of 1.0 or less. Thus, a polypropylene biaxially stretched composite film stretched or heat treated at a temperature equal to or higher than the crystalline melting point of the crystalline ethylene propylene copolymer is disclosed.
Further, in Patent Document 2, in order to improve heat sealability, a polypropylene composite film has a propylene content of 55 to 85 mol% on a base layer composed of an isotactic polypropylene layer, a differential scanning type. A polyolefin composition layer comprising 95 to 50% by weight of a propylene-1-butene random copolymer having a crystal melting heat of 10 to 80 Joules / g based on thermal analysis of a calorimeter and 5 to 50% by weight of isotactic polypropylene. It is disclosed that they are laminated.
Patent Document 3 discloses that at least one of A: crystalline polypropylene or crystalline pyropyrene-α-olefin (excluding propylene) copolymer is provided on at least one surface of a biaxially stretched film made of a crystalline polypropylene polymer. 99 to 30 parts by weight, B: 1 to 70 parts by weight of polyethylene, C: 100 parts by weight of (A + B) at least one organic peroxide having a decomposition temperature of 60 ° C. or higher for obtaining a half-life of 10 hours A translucent polypropylene biaxially stretched laminated film is disclosed, in which a film obtained by stretching 0.01 to 1.0 part by weight of a composition composed of A to C in at least uniaxial direction is laminated. Yes.
Patent Document 4 discloses a film-like film oriented in a uniaxial direction on at least one surface of a biaxially oriented polypropylene film as a matte film that easily causes irregular reflection on the surface and transmits light very easily. , A layer containing an ethylene-propylene block copolymer is laminated, and the laminated ethylene-propylene block copolymer is measured at 120 to 125 ° C. and 145 to 162 ° C. in the spectrum measured by the suggested scanning calorific value, respectively. There is disclosed a matte film having apexes of the first and second melting peaks, and the heats of fusion H1 and H2 at each peak satisfying the relationship of 0.05 ≦ H1 / (H1 + H2) ≦ 0.25.

By the way, for example, a multilayer film having a layer containing a crystalline resin having a relatively low melting point, such as random polypropylene or random polyethylene having a lower melting point than the polypropylene homopolymer, does not melt or partially melts this layer. Since the film is stretched in the machine direction (MD) (hereinafter also referred to as “MD stretching” or “longitudinal stretching”) by a roll at a low temperature that does not completely melt, the original fabric has a higher degree of orientation than usual. A film after uniaxial stretching of this high degree of orientation is usually difficult to stretch in the direction perpendicular to the machine direction (TD) (hereinafter also referred to as “TD stretching” or “lateral stretching”) by a tenter. When the film is biaxially stretched to a desired thickness at a temperature lower than the normal TD stretching temperature, there is a possibility that the film is broken or uneven in thickness due to uneven thickness.
On the other hand, if the temperature of TD stretching is set higher than the temperature of MD stretching in order to suppress breakage of TD stretching, melting is promoted in a layer having a low melting point, and recrystallization occurs at the time of subsequent cooling. Not only is the transparency of the layer significantly reduced, but the transparency of the entire multilayer film is also reduced.

Japanese Patent Publication No.49-14343 JP-A-54-95684 Japanese Patent Publication No. 58-47412 Japanese Patent Publication No.57-32954

  The present invention has been made in view of the above circumstances, and is a multilayer film having a layer containing a crystalline resin having a relatively low melting point, the fracture is suppressed even when biaxially stretched, and mechanical properties (for example, elastic modulus) ) And optical characteristics (for example, haze, gloss).

As a result of extensive research, the present inventors have found that in a multilayer film having a layer containing a crystalline resin having a relatively low melting point, an olefinic system having a specific structure having a low melting endotherm in a layer having a relatively high melting point. It discovered that the said objective was achieved by mix | blending polymer (I). The present invention has been completed based on such findings.
That is, the present invention provides the following inventions.
[1] A melting point (A) including a layer A having a melting point (Tm-D) of 80 ° C. or more and 155 ° C. or less and an olefin polymer (I) having a melting endotherm (ΔH-D) of 0 to 80 J / g. And a B layer having a Tm-D) exceeding 155 ° C.
[2] The film according to [1], wherein the olefin polymer (I) is contained in the B layer in an amount of 0.1% by mass or more and less than 50% by mass.
[3] The film according to the above [1] or [2], wherein the A layer forms at least one outermost layer.
[4] The film according to any one of [1] to [3], wherein the B layer includes an olefin polymer (II) having a melting point (Tm-D) of 155 ° C. or higher and 190 ° C. or lower.
[5] The film according to any one of [1] to [4], wherein the B layer has a melting point (Tm-D) of more than 155 ° C and not more than 190 ° C.
[6] The film according to any one of [1] to [5], wherein the layer A includes an olefin polymer (III) having a melting point (Tm-D) of 80 ° C. or higher and 155 ° C. or lower.
[7] The film according to any one of [1] to [6], wherein 50 mol% or more of the olefin polymer (I) is a propylene polymer (Ia) composed of a propylene monomer. .
[8] The above-mentioned [1] to [7], wherein the olefin polymer (I) is a propylene polymer (Ib) satisfying at least one of the following (i) and (ii): The film in any one.
(I) A structural unit of ethylene is contained in an amount of more than 0 mol% and 25 mol% or less.
(Ii) The structural unit of 1-butene is contained in an amount of more than 0 mol% and 30 mol% or less.
[9] The film according to [7], wherein the olefin polymer (I) satisfies the following (1).
(1) [mmmm] is 20 to 60 mol%.
[10] The film according to [9], wherein the olefin polymer (I) satisfies the following (2) and (3).
(2) [rrrr] / (1- [mmmm]) ≦ 0.1
(3) Molecular weight distribution (Mw / Mn) <4.0
[11] The film according to [9] or [10], wherein the olefin polymer (I) satisfies the following (4) and (5).
(4) [rmrm]> 2.5 mol%
(5) [mm] × [rr] / [mr] ² ≦ 2.0
[12] The film according to any one of [1] to [11], which is a stretched film.
[13] The film according to any one of [1] to [11], which is a biaxially stretched film.
[14] A melting point including a layer A having a melting point (Tm-D) of 80 ° C. or more and 155 ° C. or less and an olefin polymer (I) having a melting endotherm (ΔH-D) of 0 to 80 J / g. The manufacturing method of the stretched film obtained by heating a film including Tm-D) B layer exceeding 155 degreeC, and extending | stretching simultaneously or sequentially to a uniaxial or biaxial direction.
[15] A packaging material comprising the film according to any one of [1] to [13].

  According to the present invention, even when a multilayer film having a layer containing a crystalline resin having a relatively low melting point is biaxially stretched at a temperature lower than the normal stretching temperature, breakage is suppressed, and mechanical properties (for example, elastic modulus) And a film excellent in optical properties (for example, haze and gloss) can be provided.

  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.

[the film]
The film of the present invention comprises an A layer having a melting point (Tm-D) of 80 ° C. or more and 155 ° C. or less, and an olefin polymer (I) having a melting endotherm (ΔH-D) of 0 to 80 J / g. And a B layer having a melting point (Tm-D) exceeding 155 ° C.
Here, the melting endotherm (ΔH−D) is obtained by using a differential scanning calorimeter (DSC), holding the sample at −10 ° C. for 5 minutes in a nitrogen atmosphere, and then raising the temperature at 10 ° C./min. Calculated by calculating the area surrounded by the line containing the peak of the melting endothermic curve, the low-temperature point with no caloric change, and the high-temperature point with no caloric change (baseline) The
The film of the present invention may be a multilayer film including other layers other than the A layer and the B layer. In order to maintain the excellent optical properties of the film of the present invention, the other layers do not melt at the temperature of the amorphous resin having no melting point or the TD stretching of the present invention, as described later, or A crystalline resin having a melting point such that it partially melts but does not melt completely is preferable.
The A layer may constitute at least one outermost layer of the film of the present invention, or may constitute both outermost layers of the film of the present invention. When the A layer constitutes at least one outermost layer of the film of the present invention, the other outermost layer may be constituted by the B layer or may be constituted by other layers described later. .
Moreover, the film of this invention may have the said A layer and B layer 2 or more layers, respectively.
The film of the present invention is a multilayer film having two or more layers, and includes a multilayer film before stretching, a multilayer film after uniaxial stretching, and a multilayer film after biaxial stretching.

The film of the present invention includes the olefin polymer (I) having a melting endotherm (ΔH-D) of 0 to 80 J / g in the B layer, so that the stretchability at a low temperature is improved as compared with the conventional film. The inventors of the present application have found that.
Further, the film of the present invention comprises an A layer having a melting point (Tm-D) of 80 ° C. or more and 155 ° C. or less, and an olefin polymer (IH-D) of 0 to 80 J / g. ) And a melting point (Tm-D) exceeding 155 ° C., MD stretching is performed at a low temperature at which the A layer does not melt or partially melts but does not melt completely, and then normal TD stretching. Even if it is TD-stretched to a desired thickness at a low temperature that is lower than the temperature, the layer A does not melt or partially melts, but does not melt completely, it is excellent in mechanical properties (for example, elastic modulus), and is excellent in optical properties. Excellent properties (for example, haze and gloss).
Therefore, when the A layer having a melting point (Tm-D) of 80 ° C. or higher and 155 ° C. or lower is used as the outermost layer, biaxially stretched multilayer films used for various applications as described below can be obtained.
(I) A highly transparent heat-sealable biaxially stretched multilayer film that suppresses melting of the skin layer.
(Ii) A low-temperature heat-sealable biaxially stretched multilayer film having a lower melting point and softening point than before. Furthermore, a hologram-like biaxially stretched multilayer film that supports high-speed embossing by lowering the heat embossing temperature.
(Iii) A high-strength heat-sealable biaxially stretched multilayer film with a thickened heat-seal layer. Furthermore, a high-prism hologram-like biaxially stretched multilayer film with a deep embossed uneven surface.
(Iv) A mat-like biaxially stretched multilayer film with reduced unevenness.
In addition, the production line speed can be improved and the width of the production film can be widened by suppressing roll adhesion.

  Moreover, the film of this invention is 0.1 mass% or more and less than 50 mass% from a viewpoint of a drawability and an optical characteristic with respect to the composition in which content of the said olefin polymer (I) comprises B layer. More preferably 0.5% by mass or more and less than 20% by mass, further preferably 0.5% by mass or more and less than 15% by mass, and still more preferably 1% by mass or more and less than 10% by mass. is there.

Moreover, the film of this invention contains the olefin polymer (II) with which the composition which comprises B layer satisfy | fills melting | fusing point (Tm-D) 155 degreeC or more and 190 degrees C or less from a viewpoint of stretchability and an optical characteristic. The melting point (Tm-D) of the olefin polymer (II) is preferably 155 ° C. or higher and 180 ° C. or lower, more preferably 155 ° C. or higher and 170 ° C. or lower.
Here, in the present specification, the melting point (Tm-D) was measured using a differential scanning calorimeter (Perkin Elmer, DSC-7), and 10 mg of a sample was held at −10 ° C. for 5 minutes in a nitrogen atmosphere. Thereafter, the value is the peak top value of the peak observed on the highest temperature side of the melting endothermic curve obtained by raising the temperature at 10 ° C./min.

  In the film of the present invention, the melting point (Tm-D) of the B layer is preferably from 155 ° C. to 190 ° C., more preferably from 155 ° C. to 180 ° C., from the viewpoint of stretchability and optical properties. ° C or lower, more preferably 155 ° C or higher and 170 ° C or lower.

The film of the present invention has a melting point (Tm-D) of the olefin polymer (III) contained in the A layer from the viewpoint of imparting various functions to the film. It is preferably lower than the melting point (Tm-D).
Hereafter, each component used for this invention and a manufacturing method are demonstrated one by one.

[B layer]
<Olefin polymer (I)>
The olefin polymer (I) used in the present invention is heated at 10 ° C./min after holding the sample at −10 ° C. for 5 minutes in a nitrogen atmosphere using a differential scanning calorimeter (DSC). The melting endotherm (ΔH−D) obtained from the melting endotherm curve is 0 to 80 J / g.
The olefin polymer (I) in the present invention is preferably an olefin polymer (I) 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.
The olefin polymer (I) obtained by polymerizing one of these alone may be used, or the olefin copolymer (I-1) obtained by copolymerizing two or more in combination is used. May be. As the olefin copolymer (I-1), an ethylene polymer in which 50 mol% or more of the monomer constituting the polymer is an ethylene monomer, and 50 mol% or more of the monomer constituting the polymer is a propylene monomer. Propylene polymer (Ia), butene polymer in which 50 mol% or more of monomers constituting the polymer are butene monomers, and the like, and excellent molded article physical properties from the viewpoint of transparency and stretching unevenness suppression, For example, a propylene polymer (Ia) that can provide film properties is more preferable.
As propylene polymer (Ia), propylene homopolymer, propylene-ethylene block copolymer, propylene-butene block copolymer, propylene-α-olefin block copolymer, propylene-ethylene random copolymer , A propylene-based polymer (Ia) selected from propylene-butene random copolymer, propylene-α-olefin random copolymer, propylene-α-olefin graft copolymer, etc. Propylene homopolymer is preferred.

In the film of the present invention, when the olefin polymer (II) that is the main component of the B layer is a propylene polymer (II-1), the olefin polymer (I) has the following structural units. Propylene-based polymer (Ib) can also be used.
That is, when the propylene polymer (Ib) 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. More than 25 mol%, more preferably more than 0 mol%, more than 23 mol%, still more preferably more than 0 mol%, less than 20 mol%, still more preferably more than 0 mol% and more than 18 mol% % Or less. 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.
In the biaxially stretched multilayer film of the present invention, when the olefin polymer (II) that is the main component of the B layer is a propylene polymer (II-1) described later, the main component propylene polymer (II-1) From the viewpoint of compatibility with II-1), the olefin polymer (I) 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.

The film of the present invention contains the olefin polymer (I) with respect to the composition constituting the B layer, so that the ratio of the amorphous component increases and the yield stress when the polyolefin composition is stretched decreases. Therefore, the uniform stretchability is improved, and the tenacity of the formed body, for example, the formed film is improved.
In particular, from the viewpoint of greatly improving the low-temperature stretchability and optical properties of the film of the present invention, in order to increase the proportion of the amorphous component in the B layer, the composition constituting the B layer is olefin-based. The content of the polymer (I) is preferably 0.1% by mass or more and less than 50% by mass, more preferably 0.5% by mass or more and less than 20% by mass, and further preferably 0.5% by mass. As mentioned above, it is less than 15 mass%, More preferably, it is 1 mass% or more and less than 10 mass%.
In particular, the olefin polymer (II) is a propylene polymer (II-1), and the olefin polymer (I) is a propylene polymer (Ia) or a propylene polymer. In the case of (Ib), the compatibility of the propylene polymer (Ia) or the propylene polymer (Ib) with respect to the propylene polymer (II-1) also becomes better and more excellent. A molded body having transparency and stretchability can be obtained.

  The olefin polymer (I) 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 (Ia)), the content of the olefin polymer (I) is in the above-described range. It is preferable.

(Melting endotherm (ΔH-D))
The melting endotherm (ΔH-D) of the olefin polymer (I), the propylene polymer (Ia) and the propylene polymer (Ib) is 0 to 80 J / g. When the melting endotherm (ΔH-D) of the olefin polymer (I), propylene polymer (Ia) and propylene polymer (Ib) is 0 to 80 J / g, the biaxiality of the present invention With respect to the olefin polymer (II) which is the main component of the B layer of the stretched multilayer film (particularly when the olefin polymer (II) is a propylene polymer (II-1)), the crystallinity is Reduce. 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.
As described above, the melting endotherm (ΔH-D) is the melting endotherm (ΔHD): a differential scanning calorimeter (DSC) is used, and the sample is held at −10 ° C. for 5 minutes in a nitrogen atmosphere. After that, the line including the peak of the melting endothermic curve obtained by raising the temperature at 10 ° C./min, the line on the low temperature side without any change in calorie and the point on the high temperature side without any change in calorie (baseline And the area surrounded by

In the present invention, the olefin polymer (I), the propylene polymer (Ia) and the propylene polymer (Ib) are preferably propylene polymers satisfying the following (1), more preferably, Further, a propylene polymer satisfying (2) and (3), more preferably a propylene polymer satisfying the following (4) and (5) in addition to the following (1) to (3).
(1) [mmmm] is 20 to 60 mol%.
(2) [rrrr] / (1- [mmmm]) ≦ 0.1
(3) Molecular weight distribution (Mw / Mn) <4.0
(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 (I) and the propylene polymer, and the stereoregularity increases as the mesopentad fraction [mmmm] increases.
When the olefin polymer (I) 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 (II). 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 rigidity of the olefin polymer (II), which is the main component of the B layer of the film of the present invention, is not lowered, and the stretchability can be improved. If it is 60 mol% or less, the main component olefin polymer (II) is not co-crystallized and is compatible with the amorphous part of the main component olefin polymer (II). Can be improved.

(2) [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%.
The value of [rrrr] / (1- [mmmm]) in the olefin polymer (I), the propylene polymer (Ia), and the propylene polymer (Ib) is preferably from the viewpoint of stickiness. It is 0.1 or less, More preferably, it is 0.001-0.05, More preferably, it is 0.001-0.04, Most preferably, it is 0.01-0.04.

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.

(3) Molecular weight distribution (Mw / Mn)
The molecular weight distribution (Mw / Mn) of the olefin polymer (I), propylene polymer (Ia) and propylene polymer (Ib) is preferably less than 4.0 from the viewpoint of high strength. is there. When the molecular weight distribution (Mw / Mn) is less than 4.0, 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 (I), the propylene polymer (Ia) and the propylene polymer (Ib) is preferably 2.5 or less, More preferably, it is 1.5-2.5.
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).

(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 (I), propylene polymer (Ia) and propylene polymer (Ib) is preferably more than 2.5 mol%. . When [rmrm] of the olefin polymer (I), the propylene polymer (Ia), and the propylene polymer (Ib) exceeds 2.5 mol%, the randomness is increased. Eutectic with the olefin polymer (II) that is the main component of the B layer of the biaxially stretched multilayer film (especially when the olefin polymer (II) is a propylene polymer (II-1)) becomes difficult. As a result, a decrease in heat resistance and rigidity of the polyolefin-based composition is suppressed. From such a viewpoint, the racemic meso racemic meso pentad fraction [rmrm] of the olefin polymer (II) and the propylene polymer (II-1) is more preferably 2.6 mol% or more, still more preferably It is 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 (II) (in particular, the olefin polymer (II) is a propylene polymer (II-1) which is the main component of the B layer of the biaxially stretched multilayer film of the present invention. Eutectic is not caused and the olefin polymer (II) as a main component (particularly, propylene polymer (II-1)) is efficiently improved. be able to. In the present invention, the olefin polymer (I), the propylene polymer (Ia) and the propylene polymer (Ib) usually have a value of 2 or less, preferably 1.8 to 0.00. 5, More preferably, it is the range of 1.5-0.5. In addition, the unit of [mm] and [rr] in the above is mol%.
The weight average molecular weight (Mw) of the olefin polymer (I), the propylene polymer (Ia) and the propylene polymer (Ib) is 10,000 or more and 500,000 from the viewpoint of strength. The following is preferred.
When the weight average molecular weight is 10,000 or more and 500,000 or less in the olefin polymer (I), propylene polymer (Ia) and propylene polymer (Ib), the film strength is excellent. The weight average molecular weight is preferably 30,000 or more and 400,000 or less, more preferably 50,000 or more and 300,000 or less.
In the present invention, the weight molecular weight (Mw) is a weight average molecular weight (Mw) in terms of polystyrene measured by a gel permeation chromatography (GPC) method.

The propylene polymer (Ia) or (Ib) 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 (a1) or (A ′) may be produced by using the organoaluminum compound in combination.

<Olefin polymer (II)>
As described above, the olefin polymer (II) used in the present invention was held at −10 ° C. for 5 minutes under a nitrogen atmosphere using a differential scanning calorimeter (DSC) and then increased at 10 ° C./min. The melting point (Tm-D) defined as the peak top observed on the highest temperature side of the melting endothermic curve obtained by heating is preferably 155 ° C. or higher and 190 ° C. or lower.
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 (II) of the present embodiment is preferably an olefin polymer obtained by polymerizing at least one monomer 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 ( II-1), butene-based polymers in which 50 mol% or more of monomers constituting the polymer are butene monomers, and the like, and excellent molded article physical properties such as film physical properties can be obtained from the viewpoint of rigidity and transparency. The propylene polymer (II-1) is more preferable. Furthermore, the propylene polymer (II-1) preferably has a mesopentad fraction [mmmm] described later of 70 to 99 mol%, more preferably 80 to 98.5 mol%, from the viewpoint of improving rigidity and transparency. More preferably 85 to 98 mol%, still more preferably 87 to 97.5 mol%, still more preferably 88 to 97.5 mol%, and still more preferably 89 to 97.5 mol%. is there.
As propylene polymer (II-1), propylene homopolymer, propylene-ethylene block copolymer, propylene-butene block copolymer, propylene-α-olefin block copolymer, propylene-ethylene random copolymer , A propylene-based polymer (II-1) selected from propylene-butene random copolymer, propylene-α-olefin random copolymer, propylene-α-olefin graft copolymer, and the like.
Furthermore, the olefin polymer (II) 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.

  The content of the olefin polymer (II) is preferably 50% by mass or more with respect to the composition constituting the B layer. When the content is 50% by mass or more, the heat resistance of the biaxially stretched multilayer film is maintained. From such a viewpoint, the content of the olefin polymer (II) is preferably 80% by mass or more, more preferably 85% by mass or more, and further preferably 90% by mass with respect to the composition constituting the B layer. It is. Moreover, from the viewpoint of transparency and heat resistance of the biaxially stretched multilayer film, it is preferably 98% by mass or less, more preferably 95% by mass or less.

[A layer]
In the film of the present invention, the melting point (Tm-D) of the olefin polymer (III) contained in the A layer satisfies 80 ° C. or more and 155 ° C. or less from the viewpoint of imparting various functions to the film. If an olefin polymer having a melting point in the above range is used, the A layer can be used, for example, as a heat seal layer that is melted by heat and adhered to the other.
As the olefin polymer (III), materials such as polypropylene (PP), polyethylene (PE), polyethylene terephthalate copolymer (PET-G), and polybutylene terephthalate (PBT) can be used.

[Other layers]
The film of this invention may have other layers other than the above-mentioned A and B layers. In order to maintain the excellent optical properties of the film of the present invention, the other layers are not melted or partially melted at the temperature of TD stretching of the present invention, or are partially melted, but not completely melted. It is preferably a crystalline resin having a melting point that does not occur.
Other layers include, for example, EVOH (ethylene-vinyl alcohol copolymer), polyvinyl alcohol, EVA (ethylene-vinyl acetate copolymer), EEA (ethylene-ethyl acrylate) used as gas barrier layers, rigid layers, and adhesive layers. Copolymer), EMA (ethylene-methyl acrylate copolymer), chlorinated polypropylene, chlorinated polyethylene, maleic acid modified polypropylene, maleic acid modified polyethylene, other modified polyolefins, polyamide, polyester, polystyrene, PVAc (polyvinyl chloride) ), Polyether, polyketone, polycarbonate, and PMMA (polymethyl methacrylate).

<Additives>
The film of the present invention may further include an antioxidant, a heat stabilizer, a weather stabilizer, at least one of the A layer, the B layer, and other layers as necessary, as long as the object of the present invention is not impaired. Antistatic agents, slip agents, 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. It is preferable to mix | blend antioxidant in the range of 0.01-5 mass% with respect to 100 mass% of whole quantity of each layer of the said film.
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 each layer of the film.
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 each layer of the film.
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 the whole quantity of each layer of the said film.
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 each layer of the film.

<Film thickness and properties>
The film of the present invention is a film having the above-described A and B layers.
When the A layer is a heat seal layer in the outermost layer, the olefin polymer (III) contained in the A layer described above is a propylene-ethylene random copolymer, a propylene-butene random copolymer, a propylene-ethylene-butene. A ternary random copolymer or a propylene-α-olefin random copolymer is more preferable.
The thickness of the film of the present invention is not particularly limited, but is 1 μm or more, preferably 2 μm or more, more preferably 5 μm or more, and 5000 μm or less, 3000 μm or less, 1000 μm or less, 400 μm or less, 250 μm or less, 80 μm or less. Is preferable.
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”.

[Method for producing stretched film]
The method for producing a stretched film of the present invention is a production method for obtaining a stretched film by reheating a film having two or more layers having the A layer and the B layer described above and simultaneously or sequentially stretching in a biaxial direction. is there.
Here, regarding the film of the present invention, a general production method will be described below by taking the film including the A layer and the B layer described above as an example. In addition, in this invention, it does not restrict to the following manufacturing methods.
The polyolefin composition constituting the layer B is composed of the olefin polymer (I) and the olefin polymer (II), and, if necessary, an additive, for example, a high speed mixer, a Banbury mixer, a continuous kneader, In general, a method of granulating by heat melting and kneading using a normal mixing and kneading machine such as a single-screw or twin-screw extruder, a roll, or a Brabender plastograph is employed.
The polyolefin-based composition constituting the B layer is preferably used for extrusion molding. Further, the olefin polymer (I) and the olefin polymer (II) may be used by immediately feeding them into a hopper on an extruder (dry blending) immediately before extrusion molding, for example.
On the other hand, the polyolefin composition constituting the A layer is also granulated or dry blended in the same manner as described above with the addition of an olefin polymer (III) and, if necessary, an additive.
Next, the respective polyolefin-based compositions constituting the obtained layers A and B are melt-coextruded 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 an extruded primary film is continuously subjected to roll stretching and sequential biaxial stretching by a tenter method, simultaneous biaxial stretching by a tenter method, or simultaneous biaxial stretching 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 155 ° C, more preferably 80 to 150 ° 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 120 to 175 ° C., more preferably 130 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 100 to 175 ° C., more preferably 110 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 by the perpendicular direction (TD) is usually 4 to 40 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, it is possible to stretch at a surface magnification of 42 times or more, and further, it is possible to stretch at a higher magnification than the above range of 4 to 40 times, for example, a surface magnification of 45 times or more, further 47 times or more. But stretching is possible. 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.

  Further, even if the film of the present invention is biaxially stretched at a speed higher than the normal line speed, thickness unevenness due to breakage or uneven thickness is suppressed, and mechanical characteristics (for example, elastic modulus) and optical characteristics (for example, haze, It can be expected that a stretched film having excellent gloss will be obtained.

In addition, among the biaxially stretched multilayer films in the present invention, the method for producing a polypropylene biaxially stretched multilayer film includes the propylene polymer (Ia) (particularly the melting endotherm (ΔH-D) described above and Propylene homopolymer having the above properties) 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, and further preferably 0.5% by mass. As mentioned above, it is a manufacturing method which manufactures by less than 15 mass%, More preferably, it is 1 mass% or more and less than 10 mass%.
On the other hand, the propylene-based polymer (Ia) (particularly, the propylene homopolymer having the above-mentioned melting endotherm (ΔH-D) and having the above-mentioned characteristics) has a uniform composition and a narrow molecular weight distribution, so But it can be handled as a pellet. Therefore, a film can be formed even if the propylene polymer (Ia) is dry blended with the olefin polymer (II).

[Packaging materials]
The film of the present invention is suitably used for packaging materials. Although the film of the present invention is not particularly limited, for example, a packaging material for food use or industrial use, for example, a fresh food, a processed food, a cooked product, a retort food, a confectionery, or a beverage is directly or indirectly used. (For example, confectionery boxes) used for packaging and packing materials, cigarette cases, medicines, electrical parts such as capacitors and capacitors, textiles, stationery, miscellaneous goods, plastic parts, metal parts, etc. It can be used in a wide variety of applications such as materials that can be made, or electrical parts such as capacitors and capacitors, fibers, stationery, plastic parts, various reusable containers, laboratory instruments, speaker cones, 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.
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 (I) used in the Example 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 a 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 (II) used in the examples will be described below.

<Olefin polymer (II)>
As the olefin polymer (II), “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.

<Olefin polymer (III)>
As the olefin polymer (III), “F-744NP” (Random PP resin manufactured by Prime Polymer Co., Ltd., melting point: 130 ° C.) was used.

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

Production Example 1 [Production of Olefin Polymer (I)]
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 (I) was obtained by adding an antioxidant to the obtained polymerization solution so that the content thereof was 1000 ppm by mass, and then removing n-heptane as a solvent.

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

<Evaluation with biaxially stretched multilayer film>
The physical properties of the biaxially stretched multilayer films prepared in each of 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, tensile modulus, breaking strength, elongation at break 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) Tensile modulus 200 mm × 15 mm strip-shaped test pieces were pulled with a tensile tester at a chuck-to-chuck distance of 150 mm and a pulling speed of 300 mm / min. The elongation (strain) was plotted on the horizontal axis, and the stress was plotted on the vertical axis. 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 “tensile modulus”. The higher the tensile modulus, the better the rigidity of the film.
(Ii) Break strength On the relationship line (curve) on the two-dimensional coordinate axis, the maximum tensile stress appearing on the test piece before the test piece broke was determined as “break strength”.
(Iii) Elongation at break Elongation at break (%) = 100 × (L−L ₀ ) / L ₀
(In the formula, L ₀ : length of the test piece before the test, L: length of the test piece at break)

(Measurement of optical properties)
(I) Transparency (haze) measurement It measured based on JISK7105 and JISK7136. Haze indicates the ratio of the amount of scattered light with a scattering angle of 4 ° or more to the total amount of light transmitted, and visually corresponds to the cloudiness of the film. In addition, transparency is so high that a haze value is small.
Haze (%) = Td / Tt × 100
(Where, Td: diffuse transmittance, Tt: total light transmittance)
(Ii) Measurement of Gloss (Gloss) The gloss was measured according to JIS K7105 and JIS Z8741. The 60-degree specular gloss was measured. Further, the higher the gloss value, the higher the glossiness.

Example 1
5% by mass of the olefin polymer (I) of Production Example 1 and the olefin polymer (II) (PP, manufactured by Prime Polymer Co., Ltd., F-300SP, melting point: 160 ° C., tensile elastic modulus: 1700 MPa, stereoregularity [mmmm]: 90%, heat of fusion (ΔH-D): 86 J / g) 95% by mass of a dry blend of resin composition in layer B, olefin polymer (III) (random PP, prime polymer) A film having a thickness of 1000 μm was produced while co-extruding at 250 ° C. with a 50 mm mm sheet molding machine manufactured by Thermo Plastics Co., Ltd. so that F-744NP (melting point: 130 ° C.) manufactured by Co., Ltd. became A layer. At this time, the thickness ratio of A layer: B layer: A layer was 1: 18: 1. Moreover, the temperature of the cooling roll at this time was 50 degreeC.
Using a table tenter made by Iwamoto Seisakusho, the obtained film sheet was preheated at 300 seconds, stretched at 6500% / minute, stretched at 154 ° C., and 5.8 times in the machine direction (MD). , And its vertical direction (TD) was simultaneously stretched 9.5 times to produce a biaxially stretched film.
The stretching yield stress at that time was detected by a detector attached to the table tenter, in the MD direction, which was detected when the stretching ratio was changed with the sheet sandwiched between chucks. Draw a relationship line (curve) on the two-dimensional coordinate axis with the horizontal axis as the MD stretch ratio and the detected stress as the vertical axis, and change the first inflection point of the relationship line (the stretch ratio from the low stretch ratio to the high stretch ratio). The maximum value of the first inflection point that appears when it was changed was determined as the stretch yield stress. The smaller the value of the stretching yield stress, the more uniform stretching is possible and the stretchability is excellent.
About the biaxially stretched film sample formed into a film, the tensile elasticity modulus, breaking strength, breaking elongation, haze, and gloss were evaluated as a film physical property value. Table 2 shows the minimum stretchable temperature, stretch yield stress, and film properties.
The minimum stretchable temperature is the stretching temperature at which the number of breaks when stretching with the table tenter was 0 out of 5 times.

Comparative Example 1
Instead of the resin of Example 1, the resin of the B layer was F-300SP (melting point: 163 ° C., tensile elastic modulus: 1700 MPa, stereoregularity [mmmm]: 90%, heat of fusion (ΔH−) manufactured by Prime Polymer Co., Ltd. D): A film sample obtained by forming a stretched film in the same manner as in Example 1 except that the stretch temperature was set to 162 ° C. using only 86 J / g). The tensile modulus, breaking strength, breaking elongation, haze, and gloss were evaluated as values. The results are shown in Table 2.

Comparative Example 2
Instead of the resin of Example 1, the resin of the B layer was F-300SP (melting point: 163 ° C., tensile elastic modulus: 1700 MPa, stereoregularity [mmmm]: 90%, heat of fusion (ΔH−) manufactured by Prime Polymer Co., Ltd. D): A film sample obtained by forming a stretched film in the same manner as in Example 1 except that the stretch temperature was 156 ° C. except that 86 J / g) was used. The tensile modulus, breaking strength, breaking elongation, haze, and gloss were evaluated as values. The results are shown in Table 2.

  As can be seen from the results of Example 1 and Comparative Example 2 in Table 2, the biaxially stretched multilayer film containing the olefin polymer (I) in the B layer has high tensile elastic modulus and breaking strength at TD, and haze and Excellent gloss.

  Since the film of the present invention is excellent in mechanical properties and optical properties after stretching, it can be used for packaging materials for food use and industrial use, such as fresh food, processed food, cooked product, retort food, confectionery, or beverage. Packaging that can be used for packaging and packing directly or indirectly (for example, confectionery boxes), cigarette cases, pharmaceuticals, electrical parts such as capacitors and capacitors, textiles, stationery, miscellaneous goods, plastic parts, metal parts, etc. It can be used for a wide range of applications such as materials that can be used for packaging, or electrical parts such as capacitors and capacitors, fibers, stationery, plastic parts, various reusable containers, laboratory equipment, speaker cones, automobile parts, or banknotes. it can. 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 (15)

A layer whose melting point (Tm-D) is 80 ° C. or higher and 155 ° C. or lower;
A B layer containing an olefin polymer (I) having a melting endotherm (ΔH-D) of 0 to 80 J / g and a melting point (Tm-D) exceeding 155 ° C.   The film according to claim 1, wherein the olefin polymer (I) is contained in the B layer in an amount of 0.1% by mass or more and less than 50% by mass.   The film according to claim 1, wherein the A layer forms at least one outermost layer.   The film of any one of Claims 1-3 in which the said B layer contains the olefin polymer (II) with which melting | fusing point (Tm-D) satisfy | fills 155 degreeC or more and 190 degrees C or less.   The film according to any one of claims 1 to 4, wherein the melting point (Tm-D) of the B layer is higher than 155 ° C and not higher than 190 ° C.   The film according to any one of claims 1 to 5, wherein the layer A contains an olefin polymer (III) having a melting point (Tm-D) of 80 ° C or higher and 155 ° C or lower.   The film according to any one of claims 1 to 6, wherein 50 mol% or more of the olefin polymer (I) is a propylene polymer (Ia) composed of a propylene monomer. The olefin polymer (I) is a propylene polymer (Ib) satisfying at least one of the following (i) and (ii): Film.
(I) A structural unit of ethylene is contained in an amount of more than 0 mol% and 25 mol% or less.
(Ii) The structural unit of 1-butene is contained in an amount of more than 0 mol% and 30 mol% or less. The film according to claim 7, wherein the olefin polymer (I) satisfies the following (1).
(1) [mmmm] is 20 to 60 mol%. The film according to claim 9, wherein the olefin polymer (I) satisfies the following (2) and (3).
(2) [rrrr] / (1- [mmmm]) ≦ 0.1
(3) Molecular weight distribution (Mw / Mn) <4.0 The film according to claim 9 or 10, wherein the olefin polymer (I) satisfies the following (4) and (5).
(4) [rmrm]> 2.5 mol%
(5) [mm] × [rr] / [mr] ² ≦ 2.0   The film according to any one of claims 1 to 11, which is a stretched film.   The film according to any one of claims 1 to 11, which is a biaxially stretched film.   The melting point (Tm-D) includes an A layer having a melting point (Tm-D) of 80 ° C. or more and 155 ° C. or less and an olefin polymer (I) having a melting endotherm (ΔH-D) of 0 to 80 J / g. ) Includes a B layer exceeding 155 ° C., and a method for producing a stretched film obtained by heating the film and stretching it simultaneously or sequentially in a uniaxial or biaxial direction.   The packaging material which consists of a film of any one of Claims 1-13.