JP2016030767A - Polyolefin composition, polyolefin stretched film, stretched multilayer film and method for producing stretched film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyolefin composition excellent in transparency which hardly causes dropping of an antiblocking agent while maintaining blocking resistance in comparison with conventional one.SOLUTION: There is provided a polyolefin composition comprising the following (a) to (c) components, wherein the content of an olefinic polymer (A) is 0.5 mass% or more and less than 50 mass% based on 100 mass% of the total amount of (a) and (b): (a) an olefinic polymer (A) having a melting endothermic amount (ΔH-D) obtained from a melting endotherm curve which is obtained by retaining a sample in a nitrogen atmosphere at -10°C for 5 minutes and then heating at 10°C/min using a differential scanning calorimeter (DSC) of 0 to 80 J/g and a molecular weight distribution (Mw/Mn) of less than 3.0, (b) an olefinic polymer (B) having a melting point (Tm-D) measured by a differential scanning calorimeter (DSC) of more than 120°C, and (c) an antiblocking agent.SELECTED DRAWING: None

Description

  The present invention relates to a polyolefin composition, a stretched polyolefin film, a stretched multilayer film, and a method for producing a stretched film.

  Polypropylene stretched film is inexpensive and has excellent transparency, surface gloss, heat resistance, and mechanical properties (for example, rigidity (so-called “waist” of film), strength, and impact resistance). It is used for packaging materials and electrical materials such as capacitors and capacitors, and its demand is rapidly increasing. A general method for producing such a polypropylene stretched film is a simultaneous biaxial stretching method using a tubular method, a sequential biaxial stretching method using a heating roll and a tenter (tenter method), or the like. Furthermore, in the tenter method, the stretching ratio in the machine direction of the film (MD: Machine Direction, also referred to as “flow direction”) and the direction perpendicular to the machine direction (TD: Transverse Direction, also referred to as “transverse direction”) is usually 5 to 12 times. In addition, the line speed at this time is generally 200 to 525 m / min.

In particular, the biaxially stretched polypropylene film is one of the uses in which the amount of polypropylene used is large among the uses of polypropylene.
However, the biaxially oriented polypropylene film is widely used for food packaging and the like, but has a drawback that the blocking resistance is remarkably inferior due to its smoothness.
Many studies have been made in order to solve such problems, and a method of adding inorganic fine particles to impart minute unevenness to the surface of the film and suppress adhesion between the films, For example, a method of adding organic fine particles (see, for example, Patent Document 2) has been proposed.
However, in the above method, when polypropylene blended with fine particles is stretched into a film shape, the polypropylene around the fine particles is stretched, resulting in the generation of pores (hereinafter also referred to as “voids”) around the fine particles. There was a drawback that the transparency deteriorated.

  In order to solve such problems, a method of adding fine polymer particles having a specific particle size (see, for example, Patent Document 3), an inorganic or organic antiblocking agent having a specific particle size, and an acid-modified low molecular weight A method of adding polypropylene (for example, see Patent Document 4) has been proposed. However, even with polypropylene films containing fine polymer particles of a specific particle size, the improvement in film transparency is insufficient even if the voids can be reduced compared to conventional methods, or fine particles fall off from the film when the film is wound. Thus, there is a problem that the fine particles contaminate the film winding roll. Further, when an acid-modified low molecular weight polypropylene is used in such an amount that the effect of improving the transparency of the film is exhibited, there is a problem that the moldability is inferior at the time of film formation.

Japanese Patent Publication No. 52-16134 Japanese Patent Publication No. 50-36262 JP-A-9-59446 JP-A-6-73202

  The present invention has been made in view of the above circumstances, and compared with the prior art, a polypropylene resin composition, a polyolefin stretched film, a stretched multilayer film, and a highly transparent polypropylene resin composition with less loss of the antiblocking agent while maintaining blocking resistance, and It aims at providing the manufacturing method of a stretched film.

As a result of intensive studies, the inventors have formulated a small amount or less than half of the olefin polymer (A) having a specific structure having a relatively low melting endotherm in the polyolefin composition. The present inventors have found that the above object is achieved. The present invention has been completed based on such findings.
That is, the present invention provides the following inventions.
[1] A polyolefin composition comprising the following components (a) to (c), wherein the content of the olefin polymer (A) is 0, with the total amount of (a) and (b) being 100% by mass. A polyolefin composition having a content of 5% by mass or more and less than 50% by mass.
(A) 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 (A) having a calorific value (ΔH-D) of 0 to 80 J / g and a molecular weight distribution (Mw / Mn) of less than 3.0
(B) Olefin polymer (B) having a melting point (Tm-D) measured by a differential scanning calorimeter (DSC) exceeding 120 ° C.
(C) Anti-blocking agent [2] The content of the olefin polymer (B) is 50% by mass or more, where the total amount of the component (a) and the component (b) is 100% by mass. ] The polyolefin composition as described in.
[3] The polyolefin composition according to the above [1] or [2], wherein 50 mol% or more of the olefin polymer (A) is a propylene polymer (A ′) composed of a propylene monomer.
[4] The polyolefin composition according to claim 3, wherein the olefin polymer (A) is a propylene polymer (A ′) satisfying (i) to (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 of more than 0 mol% and 30 mol% or less.
[5] The polyolefin composition according to [4], wherein the olefin polymer (A) is a propylene polymer (A ′) that 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.
[6] The polyolefin composition according to any one of [1] to [5], wherein the olefin polymer (B) is a propylene polymer (B ′).
[7] Any of the above [1] to [3], [6], wherein the olefin polymer (A) is a propylene polymer (A ′) satisfying either of the following (1) or (2): The polyolefin composition as described in any one.
(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.
[8] The polyolefin composition according to [7], wherein the olefin polymer (A) is a propylene polymer (A ′) satisfying the following (3).
(3) [rrrr] / (1- [mmmm]) ≦ 0.1
[9] The polyolefin composition according to the above [7] or [8], wherein the olefin polymer (A) is a propylene polymer (A ′) satisfying the following (4) and (5).
(4) [rmrm]> 2.5 mol%
(5) [mm] × [rr] / [mr] ² ≦ 2.0
[10] A stretched film obtained by orienting the polyolefin composition according to any one of [1] to [9] in a uniaxial or biaxial direction.
[11] A multi-layer film comprising two or more layers, comprising at least one polyolefin composition according to any one of the above [1] to [9], and oriented in a uniaxial or biaxial direction Multilayer film.
[12] The stretched multilayer film according to the above [11], wherein at least one of the outermost layers of the stretched multilayer film is composed of the polyolefin composition according to any one of the above [1] to [9].
[13] A sheet including one or more layers composed of the polyolefin composition according to any one of [1] to [9] is heated, and the sheet is obtained by simultaneously or sequentially stretching in a uniaxial or biaxial direction. A method for producing a stretched film.

According to the present invention, there is provided a polyolefin composition that suppresses dropping of an antiblocking agent and is excellent in transparency of a film as compared with a conventional polyolefin raw material for stretched film.
In addition, the stretched film obtained by stretching the polyolefin composition of the present invention and the method for producing the stretched film suppress the dropping of the antiblocking agent and suppress the formation of voids during stretching of the polyolefin composition. Therefore, the resulting stretchable film has a high blocking effect and excellent transparency. In addition, the anti-blocking agent that has fallen off accumulates on the film take-up roll and becomes dirty, thereby suppressing the film surface from being damaged, and the blocking agent deposited on the film take-up roll adheres to the film surface. It also prevents the surface from becoming dirty.
Moreover, the stretched multilayer film using the polyolefin composition of the present invention for the outermost layer also suppresses the dropping of the antiblocking agent and is excellent in the transparency of the outermost layer film.

  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.

[Polyolefin composition]
The polyolefin composition of the present invention is a polyolefin composition containing the following components (a) to (c), and the content of the olefin polymer (A) is 100 in total of (a) and (b). The polyolefin composition is 0.5% by mass or more and less than 50% by mass.
(A) 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 (A) having a calorific value (ΔH-D) of 0 to 80 J / g and a molecular weight distribution (Mw / Mn) of less than 3.0
(B) Olefin polymer (B) having a melting point (Tm-D) measured by a differential scanning calorimeter (DSC) exceeding 120 ° C.
(C) Antiblocking agent The “polyolefin composition” of the present invention is suitably used as, for example, a polyolefin composition for a stretched film.

The polyolefin composition of the present invention includes an olefin polymer (A) having a melting endotherm (ΔH-D) of 0 to 80 J / g and a molecular weight distribution (Mw / Mn) of less than 3.0. Since the ratio of the amorphous component increases and the yield stress when the polyolefin composition is stretched is reduced, the uniform stretchability is improved and the tenacity of the film formed is improved.
In particular, from the viewpoint of greatly improving the uniform stretchability of the polyolefin composition, in order to increase the ratio of the amorphous component in the polyolefin composition, the melting endotherm (ΔH-D) and the molecular weight distribution (Mw / Mn) ) Having an olefin polymer (A) content of 0.5% by mass or more and 50% by mass with respect to the total content of the olefin polymer (A) and the olefin polymer (B). It is less than 0.5%, preferably less than 30%, more preferably less than 0.5%, less than 15%, still more preferably more than 1% and less than 10%.

In the polyolefin composition of the present invention, the content of the olefin polymer (A) is 0.5 mass relative to the total content of the olefin polymer (A) and the olefin polymer (B). % Or more and less than 50% by mass, the uniform stretchability is greatly improved without affecting the mechanical properties and optical properties of the film.
In particular, from the viewpoint of greatly improving the stretchability without affecting the mechanical properties and optical properties of the film, the olefin polymer (A) has the melting endotherm (ΔH-D) and molecular weight distribution (Mw). / Mn) and the characteristics described later (particularly, in the case of propylene polymer (A ′)), the content of the olefin polymer (A) is within the above range. An amount is preferred.

  From the viewpoint of heat resistance, the melting point of the polyolefin composition of the present invention is preferably 100 ° C or higher, more preferably 120 ° C or higher, and particularly preferably 140 ° C or higher.

In the present invention, in particular, the olefin polymer (A) (particularly the propylene polymer (A ′)) having the melting endotherm (ΔH-D) and having the characteristics described later is a main component or an equivalent amount. It is surmised that the compatibility with the olefin polymer (B) is remarkably high and the primary structure is the most similar, so that the characteristics of excellent optical properties are exhibited.
Further, the olefin polymer (A) (particularly the propylene polymer (A ′)) having the above-mentioned melting endotherm (ΔH−D) and having the characteristics described later is a conventional technology such as ethylene or 1- Compared with a propylene-α-olefin copolymer using a comonomer such as butene, the crystallization rate is low. This is because the propylene-α-olefin copolymer has high stereoregularity, and the rate of forming a 3/1 helix necessary for crystallization is equivalent to that of a highly stereoregular propylene polymer that does not use a comonomer. The olefin polymer (A) having the above-mentioned melting endotherm (ΔH-D) and having the characteristics described later has an appropriate degree of stereoregularity in the molecular chain. / 1 This is because the rate of forming a helix is significantly slower than that of a highly stereoregular propylene polymer that does not use a comonomer. When a material with a slow crystallization rate is added to the polypropylene resin composition, which is the main component, the crystallization rate of the entire resin composition becomes slow, and if the crystallization rate of the whole resin composition becomes slow, the growth rate of spherulites Is slow, the size of the growing spherulites is reduced, and the spherulite breaking stress during stretching is reduced, so that it is assumed that uniform and easy stretching can be realized.

  In the present invention, uniform stretching is particularly achieved by using an olefin polymer (A) (particularly a propylene polymer (A ′)) having the above-mentioned melting endotherm (ΔHD) and having the characteristics described later. As a result, the uniform stretching force is applied to the entire film, and the formation of voids generated by the separation of the interface between the anti-blocking agent and the polyolefin composition due to the application of a strong local force is suppressed. It is guessed. Moreover, since the local force is not applied also to the thin film of the polyolefin composition covered with the antiblocking agent in the vicinity of the film surface, it is estimated that the breakage of the thin film is suppressed. Moreover, it is speculated that the thin film breakage is suppressed against the stress generated by the friction between the films or the winding roll with respect to the anti-blocking agent in the vicinity of the film surface by improving the tenacity of the film. .

  In the present invention, in particular, by using the olefin polymer (A) (particularly the propylene polymer (A ′)) having the above melting endotherm (ΔH-D) and having the characteristics described later, When the polyolefin composition is stretched into a film, dropping of the antiblocking agent from the film is suppressed. Therefore, even if the addition amount is smaller than the addition amount of the anti-blocking agent required when the olefin polymer (A) is not added, it is equal to or greater than that when the olefin polymer (A) is not added. It shows the blocking resistance. The amount of the anti-blocking agent added particularly greatly affects the optical properties of the stretched film, particularly the transparency (for example, “haze” as an indicator of haze). In particular, in a general-purpose film having a thickness of about 20 μm in which the raw material is sufficiently cooled, the type and amount of the antiblocking agent dominate the transparency of the film. While blending the olefin polymer (A) to prevent the anti-blocking agent from falling off from the film during film stretching, reducing the amount of the anti-blocking agent to be blended is a stretched film (especially biaxial stretching). This is a very effective means for reducing the haze (that is, improving the transparency) of the film.

Furthermore, the antiblocking agent usually uses fine particles having a small particle size. The fine particles have a drawback that their cohesion is strong and their dispersibility is poor due to their large surface area. On the other hand, since the olefin polymer (A) is excellent in dispersibility and diffusibility of fine particles and additives, the olefin polymer (A) is used for a stretched film (particularly, a biaxially stretched film). It also has a function to help dispersibility of the anti-blocking agent composed of fine particles.
For example, when the anti-blocking agent causes poor dispersion in the polyolefin composition, the portion of poor dispersion rises greatly on the film surface after stretching the film, and the blocking resistance of the entire film deteriorates. Furthermore, if the thin resin skin covering the anti-blocking agent on the surface of the film that is greatly raised is peeled off, a large amount of anti-blocking agent will fall off the film, and the anti-blocking agent that has fallen will accumulate on the film take-up roll. It is presumed that the quality of the film is deteriorated due to the dirt caused by the damage, and the film surface is scratched, or the blocking agent deposited on the film take-up roll adheres to the film surface and soils the surface. Furthermore, there is a possibility that the printing process using the converter may be adversely affected due to the deterioration of the quality of the film. That is, the blending of the olefin polymer (A) with the polyolefin composition of the present invention not only has an effect of suppressing the deblocking of the anti-blocking agent from the film, but also the dispersion of the anti-blocking agent into the polyolefin composition. It is estimated that it contributes to improving the performance.

  Further, in order to impart blocking resistance to the film, as described above, an anti-blocking agent is used. However, when at least one of the outermost layers of the stretched multilayer film described later is formed by the polyolefin composition of the present invention, Fine particles may also be used in the case of imparting scratch resistance to the outermost layer. The fine particles have a particle size smaller than that of the antiblocking agent, and are dispersed in the outermost layer of the stretched multilayer film, thereby improving the rigidity and suppressing the occurrence of surface scratches due to friction or the like. Fine particles for scratch resistance, like antiblocking agents, fall off from the surface of the outermost layer of the stretched multilayer film, voids form inside the outermost layer of the stretched multilayer film, and poor dispersion due to aggregation Is generated. In the case of the antiblocking agent as described above, fine particles used for imparting scratch resistance by blending the olefin polymer (A) with the polyolefin composition constituting the outermost layer of the stretched multilayer film. Shows the same effect. In particular, poor dispersion due to aggregation is likely to occur because the particle size is smaller than that of the anti-blocking agent, so it can be said that the blending of the olefin polymer (A) with the polyolefin compound is very effective.

<Olefin polymer (A)>
The olefin polymer (A) of the present invention is preferably an olefin polymer 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-dodecene. 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-icocene and the like. 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 invention, the term “olefin polymer” simply includes an olefin copolymer.

The olefin polymer (A) of the present invention is a polymer added to the polyolefin polymer (B) in a small amount to less than half, and the olefin polymer (A) of the present embodiment is, for example, propylene Homopolymer, propylene-ethylene block copolymer, propylene-butene block copolymer, propylene-α-olefin block copolymer, propylene-ethylene random copolymer, propylene-butene random copolymer, propylene-α- A propylene-based polymer (A ′) selected from an olefin random copolymer or a propylene-α-olefin graft copolymer is preferred.
In the polyolefin composition of the present invention, when the olefin polymer (B) as the main component is a propylene polymer (B ′), the compatibility with the propylene polymer (B ′) as the main component is sufficient. From the viewpoint, in the case of a copolymer containing an olefin having 2 carbon atoms, the propylene-based polymer (A ′) contains 0 mol% of the structural unit of the olefin having 2 carbons (that is, ethylene monomer). More than 20 mol%, preferably more than 0 mol%, preferably less than 18 mol%, more than 0 mol%, more preferably less than 15 mol%, more preferably more than 0 mol% and even more preferably less than 13 mol%. . 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. 75 mol% or more is more preferable, and 80 mol% or more is more preferable. 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 more than 0 mol%, preferably 30 mol% or less, and 0 mol%. More than 27 mol%, particularly preferably more than 0 mol% and more preferably 20 mol% or less. In the polyolefin composition of the present invention, when the olefin polymer (B) as the main component is a propylene polymer (B ′), the compatibility with the propylene polymer (B ′) as the main component is sufficient. From the viewpoint, the olefin polymer (A) 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.

[Melting endotherm (ΔH−D)]
The melting endotherm (ΔH−D) of the olefin polymer (A) and the propylene polymer (A ′) is 0 to 80 J / g. When the melting endotherm (ΔH-D) of the olefin polymer (A) and the propylene polymer (A ′) is 0 to 80 J / g, the olefin system that is the main component of the polyolefin composition for stretched film of the present invention. The degree of crystallinity is reduced with respect to the polymer (B) (particularly, when the olefin polymer (B) is a propylene polymer (B ′)). 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, it is 0-80 J / g, Preferably it is 10-70 J / g, More preferably, it is 20-60 J / g, More preferably, it is 30-50 J / g.
Note that the melting endotherm (ΔH−D) is the peak of the melting endotherm curve obtained by DSC measurement with the line connecting the point on the low temperature side where there is no change in calorie and the point on the high temperature side where there is no change in calorie as the baseline. Is calculated by obtaining an area surrounded by the line portion including the base line and the base line.

[Molecular weight distribution (Mw / Mn)]
The molecular weight distribution (Mw / Mn) of the olefin polymer (A) and the propylene polymer (A ′) is preferably less than 3.0 from the viewpoint of high strength. When the molecular weight distribution (Mw / Mn) is less than 3.0, low molecular weight components that adversely affect stretchability and film physical properties (for example, mechanical properties and optical properties) are suppressed. Reduction in film physical properties is suppressed. The molecular weight distribution (Mw / Mn) of the olefin polymer (A) and the propylene polymer (A ′) 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 (A) and the propylene polymer (A ′) of the present invention are preferably propylene polymers satisfying either of the following (1) or (2), and more preferably (3) More preferably, the following (4) and (5) are satisfied.
(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 propylene-based polymer, and the stereoregularity increases as the mesopentad fraction [mmmm] increases.
When the olefin polymer (A) is a propylene homopolymer, the mesopentad fraction [mmmm] is improved in handling property of the propylene polymer and stretchability when added in a small amount to the polyolefin polymer (B). 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 (B), which is the main component of the polyolefin composition for stretched films of the present invention, is not lowered, and the stretchability is improved. When it is 60 mol% or less, it is not eutectic with the main component olefin polymer (B), and is compatible with the amorphous part of the main component olefin polymer (B). Extendability can be improved.

(2) Melting point (Tm-D)
The melting point (Tm-D) of the olefin polymer (A) and the propylene polymer (A ′) is preferably higher from the viewpoints 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%.
The value of [rrrr] / (1- [mmmm]) in the olefin polymer (A) and the propylene polymer (A ′) is preferably 0.1 or less, more preferably 0, from the viewpoint of stickiness. 0.001 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) ", the meso fraction, the racemic fraction, and the racemic meso-racemic meso in pentad units in the polypropylene molecular chain measured by the signal of the methyl group in 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 (A) and the propylene polymer (A ′) is preferably more than 2.5 mol%. When [rmrm] of the olefin polymer (A) and the propylene polymer (A ′) exceeds 2.5 mol%, randomness increases, and the main component of the polyolefin composition for stretched film of the present invention. It becomes difficult to eutecticize with the olefin polymer (B) (particularly when the olefin polymer (B) is a propylene polymer (B ′)), and as a result, the heat resistance and rigidity of the polyolefin composition are reduced. Is suppressed. From such a viewpoint, the racemic meso racemic meso pentad fraction [rmrm] of the olefin polymer (A) and the propylene polymer (A ′) is preferably 2.6 mol% or more, 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, and the closer to 1, the more random The olefin polymer (B), which is the main component of the polyolefin composition for stretched films of the present invention (particularly when the olefin polymer (B) is a propylene polymer (B ′)). Crystallization does not occur, and the drawability can be efficiently improved with respect to the olefin polymer (B) (particularly, the propylene polymer (B ′)) as the main component. In the olefin polymer (A) and propylene polymer (A ′) 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. Range. In addition, the unit of [mm] and [rr] in the above is mol%.

The propylene polymer (A ′) 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 through A ¹ and A ² They may be the same or different from each other, X represents a sigma-binding ligand, and when there are a plurality of X, the plurality of X may be the same or different, and other X, E ¹ , It may be cross-linked with E ² or Y. 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. A propylene-based polymer (A ′) may be produced by using the organoaluminum compound in combination.

<Olefin polymer (B)>
The olefin polymer (B) of the present invention is a main component of the polyolefin composition of the present invention, and is a base resin for the stretched polyolefin film of the present invention described later. The olefin polymer (B) of the present embodiment is particularly limited as long as the melting point (Tm-D) measured by a differential scanning calorimeter (DSC) exceeds 120 ° C. First, an ethylene polymer in which 50 mol% or more of the monomer constituting the polymer is an ethylene monomer, a propylene polymer in which 50 mol% or more of the monomer constituting the polymer is a propylene monomer, Examples include butene-based polymers in which 50 mol% or more is a butene monomer, and propylene-based polymers that can provide excellent film properties from the viewpoint of rigidity and transparency are preferred.
Examples of the propylene polymer include propylene homopolymer, propylene-ethylene block copolymer, propylene-butene block copolymer, propylene-α-olefin block copolymer, propylene-ethylene random copolymer, propylene-butene random. A propylene-based polymer (B ′) selected from a copolymer, a propylene-α-olefin random copolymer, a propylene-α-olefin graft copolymer and the like is preferable. Furthermore, from the viewpoint of physical properties (for example, mechanical physical properties and optical physical properties) of the stretched polyolefin film, the olefin polymer (B) of the present invention is particularly preferably a propylene-ethylene random copolymer or a propylene homopolymer. . The polymer may be a polymer using a petroleum / coal-derived monomer or a polymer using a biomass-derived monomer.

<Anti-blocking agent>
Although a specific example is shown below, the anti-blocking agent used in the present application is not limited in composition or shape.
As an antiblocking agent, for example, inorganic fine powder silica, fine powder aluminum oxide, fine powder clay, fine powder metal, fine powder calcium carbonate, fine powder glass, organic polystyrene, crosslinked polystyrene, acrylic resin, Examples include crosslinked acrylic resin, methacrylic resin, crosslinked methacrylic resin, silicone resin, crosslinked silicone resin particulate resin, or liquid silicone resin, polytetrafluoroethylene resin, or resin incompatible with the constituent resin of the film. Can do. Among these, fine powder silica and fine powder resin are preferable. Moreover, as a shape, since a spherical thing is excellent in the blocking-resistant improvement effect, it is preferable.
The average particle diameter of the blocking agent is preferably 0.1 to 20 μm, more preferably 0.5 to 15 μm, and still more preferably 0.8 to 10 μm. By being in the above-mentioned range, sufficient antiblocking property and slipperiness can be achieved at the same time, and a stretched film excellent in transparency and gloss can be obtained without generating large voids in the stretched film.
The average particle size of the blocking agent should be measured using a laser diffraction particle size distribution analyzer after the blocking agent coexists with a surfactant in water and sufficiently dispersed using an ultrasonic disperser. Is possible. Here, the value calculated from the number distribution was used for the average particle diameter.

  As the scratch-resistant fine particles used for the outermost layer of the stretched multilayer film described later, the same fine particles as described above can be used, and the average particle diameter is preferably 0.001 to 10 μm, more preferably 0.01 to It is 5 μm, more preferably 0.01 to 1 μm.

  It is preferable to mix | blend an antiblocking agent in 0.01-10 mass parts with respect to 100 mass parts of polyolefin compositions, More preferably, it is 0.05-5 mass parts, More preferably, it is 0.1-1. Part by mass. As described above, since the polyolefin composition of the present invention is blended with the olefin polymer (A), the anti-blocking agent is prevented from falling out of the film as compared with the conventional case. The amount may be reduced.

〔Additive〕
The polyolefin composition for stretched film of the present invention is an antioxidant, a heat stabilizer, a weather stabilizer, an antistatic agent, a slip agent, an antifogging agent, if necessary, as long as the object of the present invention is not impaired. A lubricant, a nucleating agent, a petroleum resin, a hydrogenated petroleum resin, a dye, a pigment, a natural oil, a synthetic oil, a wax, a filler, an elastomer, 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.
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 parts by mass with respect to 100 parts by mass of the polyolefin 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 parts by mass with respect to 100 parts by mass of the polyolefin composition.

[Stretched film]
The stretched film of the present invention is a stretched film obtained by molding the polyolefin composition for stretched film of the present invention. Examples of the stretched polyolefin film include a stretched polyethylene film, a stretched polypropylene film, and a stretched polybutene film, but a stretched polypropylene film is preferred because of having excellent film properties.
In addition, the kind of stretched polyolefin film is determined by the kind of the olefin polymer (B) which is a base resin of the stretched polyolefin film and is also the main component of the polyolefin composition for stretched film.
Although there is no restriction | limiting in particular in the thickness of the stretched film of this invention, Usually, it is 2-200 micrometers, Preferably it is 7-80 micrometers.

[Stretched multilayer film]
The stretched multilayer film of the present invention has at least one layer composed of the polyolefin composition of the present invention, and is a stretched multilayer film obtained by orienting these multilayers in a uniaxial or biaxial direction from the viewpoint of antiblocking properties. It is preferable that at least one outermost layer of the stretched multilayer film is made of the polyolefin composition of the present invention. Further, the outermost layer at this time may function as a heat seal layer.
When the outermost layer is a heat seal layer, the above-mentioned olefin polymer (B) is preferable. For example, the olefin polymer (B) is a propylene-ethylene random copolymer, a propylene-butene random copolymer, or propylene. It is more preferable that it is -alpha-olefin random copolymer, and it may have a role as a heat seal layer, and may also have a role as a skin layer for blocking prevention.
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 according to the use. For example, in addition to the polyolefin resin composition, the stretched multilayer film has gas barrier properties. Examples thereof include resins (ethylene-vinyl alcohol copolymer and the like) and rigid resins (nylon and the like).
Moreover, although there is no restriction | limiting in particular in the thickness of the stretched multilayer film of this invention, Usually, it is 2-200 micrometers, Preferably it is 7-80 micrometers.

  Among the stretched films of the present invention, the polypropylene stretched film, as will be described later, is superior in stretchability, mechanical properties, and optical properties as compared to a polypropylene stretched film using a conventional polypropylene raw material, and the film is thinned and the production line speed is increased. The speed of rupture can be reduced as compared with the prior art.

[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 sheet or film comprising one or more layers comprising the polyolefin composition of the present invention, and simultaneously or sequentially stretching in a uniaxial or biaxial direction. Is the method.
Below, an example is demonstrated as a general manufacturing method of the polyolefin stretched film of this invention. In addition, in this invention, it does not restrict to the following manufacturing methods.
The polyolefin composition for stretched film of the present invention 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.
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 continuous biaxial stretching by the tenter method, simultaneous biaxial stretching by the tenter method, and simultaneous biaxial stretching by the inflation method. A batch-type biaxial stretching apparatus may be used. The extrusion stretching ratio can be appropriately determined depending on the use of the stretched film, but is uniaxially stretched or biaxially 2 to 12 times in the machine direction (MD) and / or the direction perpendicular to the machine direction (TD). It is preferable to stretch.
In the tenter method, the primary film is reheated to a temperature suitable for stretching and stretched in the machine direction (MD) between a slow (front) roll and a fast (rear) roll. Next, the film enters the tenter part, is heated while holding both ends of the film, and is stretched in the direction perpendicular to the machine direction (TD). Finally, the film is heat treated to stabilize the film properties and wound up by a winder. 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, the multilayer stretched film also has at least one outermost layer of the polyolefin composition of the present invention, and is laminated with another resin composition, and the primary film obtained by extrusion is further uniaxially stretched or biaxially stretched as described above. The stretched film may be stretched to obtain a stretched stretched film, or the extruded film may be continuously biaxially stretched by the tenter method, simultaneously biaxially stretched, or simultaneously biaxially stretched by the inflation method. Also good.

  Moreover, the polyolefin composition for stretched films of the present invention is not only a stretched film production method but also a stretched molding method, in particular, a mold method that is once solidified and then reheated and stretched (extrusion blow molding or injection blow molding). It is presumed that a beneficial effect is exhibited in any of blow molding including molding, thermoforming and the like. For example, in the blow molding used when molding a bottle, when the polyolefin composition for a stretched film of the present invention is used, the unevenness of the bottle thickness (variation) is small due to excellent stretchability, and is uniform. Since the deterioration of quality unevenness such as bottle strength is suppressed and the transparency is improved, the present invention can be applied to a polypropylene injection stretch blow bottle instead of a polyethylene terephthalate (PET) bottle.

  The draw ratio is usually 4 to 50 times with respect to the machine direction (MD) and / or the surface ratio obtained by multiplying the machine direction by the perpendicular direction (TD), but the polyolefin composition for stretched films of the present invention. When is used, stretchability is further improved, so that a higher surface magnification, for example, a stretching magnification of 50.5 times or more, further 52 times or more is possible. Thus, the film stretched at a high magnification is excellent in rigidity and transparency even if it is thin, and it is possible to suppress shrinkage of the film after stretching.

  In addition, among the stretched polyolefin films of the present invention, a method for producing a stretched polypropylene film is the propylene polymer (A ′) (particularly propylene alone having the above melting endotherm (ΔH−D) and the above-mentioned characteristics. The polymer) is a production method for molding by adding 0.5% by mass or more and less than 50% by mass to the total content of the olefin polymer (B) and the propylene polymer (A ′). . On the other hand, the propylene-based polymer (A ′) (particularly, the propylene homopolymer having the above-mentioned melting endotherm (ΔH-D) and having the above-mentioned characteristics) has a narrow composition and a narrow molecular weight distribution, so that it is a pellet even at room temperature. Can be treated as Therefore, the film can be formed even if the propylene polymer (A ′) is dry blended with the olefin polymer (B).

  The polyolefin stretched film of the present invention is not particularly limited, but for example, packaging materials for food use and industrial use, electrical materials such as capacitors and capacitors, fibers, stationery, miscellaneous goods, plastic parts, metal parts, etc. It can be used for a wide range of applications such as packaging and packaging materials, and 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.

  Below, the manufacture example of the propylene-type polymer (A'-1) used in an Example is demonstrated.

Production Example 1 [Production of Propylene Polymer (A′-1) (Propylene Homopolymer)]
To a stainless steel reactor with a stirrer and an internal volume of 0.25 m ³ , n-heptane was 26 L / hr, triisobutylaluminum was 7.7 mmol / hr, dimethylanilinium tetrakispentafluorophenylborate and (1,2 ′ -Dimethylsilylene) (2,1'-dimethylsilylene) -bis (3-trimethylsilylmethylindenyl) zirconium dichloride, triisobutylaluminum and propylene in a mass ratio of 1: 2: 20 and obtained in advance. The catalyst component was continuously fed at 6 μmol / hr in terms of zirconium.
Propylene and hydrogen were continuously supplied so as to maintain 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.
The propylene polymer (A′-1) is obtained by adding an antioxidant to the obtained polymerization solution so that the content thereof becomes 1000 ppm by mass, and then removing n-heptane as a solvent. It was.

  The following measurements were performed on the propylene polymer (A′-1) obtained in Production Example 1. The measurement results are shown in Table 1.

[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 molecular weight distribution (Mw / Mn) were determined by gel permeation chromatography (GPC). For the measurement, the following apparatus and conditions were used, and a weight average molecular weight in terms of polystyrene was obtained.
<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 using 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. The meso fraction, the racemic fraction, and the racemic meso-racemic meso in the pentad unit in the polypropylene molecular chain measured by the methyl group signal in the ¹³ C-NMR spectrum were obtained according to the proposed method. 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.

[Film formation]
The film was formed on a continuous molding pilot line made by Bruckner. The film forming conditions are as follows.
The molten resin is extruded by a continuous molding pilot machine (extruder screw system: 120 mmφ, line speed of the tenter: 48.6 m / min, T die width: 280 mm, chill roll diameter: 1500 mmφ) manufactured by Bruckner. A layer film was prepared. At this time, the chill roll temperature was 20 ° C., and the temperature of the raw fabric cooling water tank was 20 ° C. The produced single-layer film was preheated with a preheating roll and then stretched in the machine direction (MD, longitudinal stretching) under the conditions of stretching temperature: 108 ° C. and stretching ratio: 5.0 times, and both ends of the film were chucked. It passes through the tenter in a fixed state at a stretching temperature of 166 ° C., a stretching ratio of 8.5 times, a relaxation rate of 5%, and a heat fixing temperature of 166 ° C. in a direction perpendicular to the machine direction (TD, transverse Stretched) to produce a biaxially stretched film.

(Measuring mechanical properties)
Using a 200 mm × 15 mm strip-shaped test piece, the test piece was pulled with a tensile tester (manufactured by Shimadzu Corporation, Autograph AG-I) at a pulling speed of 300 mm / min, and the elastic modulus, breaking strength, and breaking elongation were determined.
(I) Elastic Modulus The elastic modulus at the time of tension in the vertical direction (TD, transverse direction) using a tensile tester was measured. The measurement conditions were as follows: a 200 mm × 15 mm strip-shaped test piece was pulled with a tensile tester at a chuck-to-chuck distance of 150 mm, a tensile speed of 300 mm / min, the elongation (strain) as the horizontal axis, and the stress as 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 “elastic modulus”. The higher the modulus of elasticity, the better the rigidity of the film.
(ii) Breaking strength On the relationship line (curve) on the two-dimensional coordinate axis, the maximum tensile stress appearing on the test piece before breaking the test piece was determined as “breaking strength”.
(Iii) Elongation at break Elongation at break (%) = 100 × (L−L ₀ ) / L ₀
(In the formula, L ₀ : length of test piece before test, L: length of test piece at break)

(Measurement of optical properties)
(I) Transparency measurement Based on JIS K7105 and JIS K7136, it measured using the Nippon Denshoku Industries ISO haze meter (NDH2000). 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) 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.
(Iii) Narrow-angle Diffuse Transmittance (LSI) Measurement It was measured using a visual transparency tester (also referred to as “LSI tester”, manufactured by Toyo Seiki Seisakusho Co., Ltd.). LSI indicates the ratio of the amount of scattered light with a scattering angle of 0.4 ° or more and 1.2 ° or less with respect to the total amount of transmitted light, and visually corresponds to the transparency of the film. This LSI is an evaluation method for a light scattering angle that is relatively small. In this case, the light scattering unit corresponds to a light scattering unit having a size of 10 μm or more. Therefore, among the light scattering factors in the film, it substantially corresponds to light scattering derived from voids (voids) generated due to the antiblocking agent. LSI was used as a measure of fluoroscopy because it corresponds quite well to the fluoroscopy observed with the naked eye. It should be noted that the smaller the LSI value, the higher the transparency (clearness / cleanness) of the film.
Narrow-angle diffuse transmittance (%) = Ts / T0 × 100
(In the formula, Ts: scattered light quantity with a scattering angle of 0.4 ° to 1.2 °, T0: total light transmitted light quantity)

[Measurement of surface properties]
The morphology of the antiblocking agent on the surface was observed using a polarizing microscope. In order for the anti-blocking agent to exhibit the blocking resistance of the film, it is necessary to form sufficient irregularities on the surface. After observation, the location where the anti-blocking agent can be expected sufficiently (X), the location where the thin skin of the resin covering the anti-blocking agent has been peeled off (Y) and the anti-blocking agent have fallen off A statistically sufficient amount was counted for three of the locations (Z) and their proportions were determined. The ratio of (Y) represents the frequency of thin skin tears, and the ratio of (Z) represents the frequency of omission of the antiblocking agent.

[Method for measuring the coefficient of static friction]
Using a static friction coefficient measuring tester (manufactured by Toyo Seiki Kogyo Co., Ltd., friction measuring machine AN type), the measurement was performed according to ASTM-D1894 at 23 ° C. and a relative humidity of 50%.

[Measurement method of blocking strength]
The chill roll surfaces of the film of 10 cm in the MD direction × 10 cm in the TD direction are overlapped and held in a thermostatic bath at 50 ° C. under a load of 200 g / cm ² for 3 days (
Same conditions except for temperature chamber). Then, after adjusting the state for 24 hours or more in a room at 23 ° C. and a relative humidity of 50%, using a tensile tester (manufactured by Shimadzu Corp., Autograph AG-I), peeling was performed at a tensile rate of 200 mm / min. The peel strength was measured, and the value obtained by dividing the peel strength by the width of the test piece was taken as a blocking coefficient to evaluate the blocking resistance. Here, the smaller the blocking coefficient, the better the blocking resistance.
Here, the MD direction means a machine direction, and the TD direction means a direction perpendicular to the machine direction.

<Evaluation of stretched film>
As shown below, stretched films were prepared, and the physical properties of each were evaluated by the measurement methods described above.

Example 1
5% by mass of the propylene polymer (A′-1) of Production Example 1 and the propylene polymer (B) (PP, manufactured by Lyondellbasell, Moplen HP525J, melting point (Tm-D): 163 ° C., tensile modulus: 1500 MPa , Stereoregularity [mmmm]: 91%, heat of fusion (ΔH-D): 84 J / g) 93% by mass and antiblocking agent master batch (A. Schulman, Polybatch ABPP05) 2% by mass The dry blend was formed into a film using the above-described continuous molding pilot line made by Bruckner. The optical properties, mechanical properties, and surface properties of the formed films were measured and evaluated based on the measurement methods described above. The results are shown in Table 2.

Comparative Example 1
Propylene polymer (B) (PP, manufactured by Lyondellbasell, Moplen HP525J, melting point: 163 ° C., tensile elastic modulus: 1500 MPa, stereoregularity [mmmm]: 91%, heat of fusion (ΔH-D): 84 J / g) A resin composition consisting of 98% by mass and 2% by mass of an antiblocking agent master batch (manufactured by A. Schulman, Polybatch ABPP05) was formed in the same manner as in Example 1, and the physical properties of the film were evaluated. The results are shown in Table 2.

  As is clear from Table 2, Example 1 containing the propylene polymer (A) is superior in optical properties to Comparative Example 1 not containing the propylene polymer (A), and is an antiblocking agent. Dropping is suppressed and the blocking resistance is also improved. The blockage of the antiblocking agent is attributed to the fact that the thin film covering the antiblocking agent is difficult to break because the tenacity of the film is improved by including the propylene polymer (A). Further, the reason why the optical properties are excellent is that the uniform stretchability of the film is improved by including the propylene-based polymer (A), and therefore the void formation frequency is suppressed.

  The polyolefin composition for stretched film of the present invention can be stretched in a lower temperature region and is excellent in mechanical properties and optical properties after stretching. Therefore, packaging materials for food use, industrial use, capacitors, capacitors, etc. It can be used for a wide range of applications such as electrical materials, fibers, stationery, plastic parts, various reusable containers, laboratory instruments, speaker cones, automobile parts, banknotes.

Claims (13)

A polyolefin composition containing the following components (a) to (c), wherein the content of the olefin polymer (A) is 0.5 mass, with the total amount of (a) and (b) being 100 mass%. % Or more and less than 50% by mass of a polyolefin composition.
(A) 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 (A) having a calorific value (ΔH-D) of 0 to 80 J / g and a molecular weight distribution (Mw / Mn) of less than 3.0
(B) Olefin polymer (B) having a melting point (Tm-D) measured by a differential scanning calorimeter (DSC) exceeding 120 ° C.
(C) Antiblocking agent   2. The polyolefin composition according to claim 1, wherein the content of the olefin polymer (B) is 50% by mass or more, where the total amount of the component (a) and the component (b) is 100% by mass.   3. The polyolefin composition according to claim 1, wherein 50 mol% or more of the olefin polymer (A) is a propylene polymer (A ′) composed of a propylene monomer. The polyolefin composition according to claim 3, wherein the olefin polymer (A) is a propylene polymer (A ′) satisfying (i) to (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 of more than 0 mol% and 30 mol% or less. The polyolefin composition according to claim 4, wherein the olefin polymer (A) is a propylene polymer (A ') that 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 polyolefin composition according to any one of claims 1 to 5, wherein the olefin polymer (B) is a propylene polymer (B '). The polyolefin composition according to any one of claims 1 to 3, wherein the olefin polymer (A) is a propylene polymer (A ') satisfying either of the following (1) or (2). object.
(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. The polyolefin composition according to claim 7, wherein the olefin polymer (A) is a propylene polymer (A ') satisfying the following (3).
(3) [rrrr] / (1- [mmmm]) ≦ 0.1 The polyolefin composition according to claim 7 or 8, wherein the olefin polymer (A) is a propylene polymer (A ') satisfying the following (4) and (5).
(4) [rmrm]> 2.5 mol%
(5) [mm] × [rr] / [mr] ² ≦ 2.0   The stretched film formed by orienting the polyolefin composition of any one of Claims 1-9 to a uniaxial or biaxial direction.   A stretched multilayer film comprising at least one layer of the polyolefin composition according to any one of claims 1 to 9 and oriented in a uniaxial or biaxial direction.   The stretched multilayer film according to claim 11, wherein at least one of the outermost layers of the stretched multilayer film is made of the polyolefin composition according to claim 1.   The manufacturing method of the stretched film obtained by heating the sheet | seat containing one or more layers which consist of a polyolefin composition of any one of Claims 1-9, and extending simultaneously or sequentially to a uniaxial or biaxial direction.