JP2000015760A - Stretch film for packaging - Google Patents

Abstract

(57) [Problem] To provide a stretch film for packaging excellent in flexibility and impact resistance, and excellent in transparency, deformation recovery property and cutability. SOLUTION: This film is composed of at least three layers, both surface layers are composed of an ethylene polymer (A), and at least one of the intermediate layers has a heat of fusion of 20 J /
g and less than 80 J / g propylene-based polymer (B)
80 to 10% by weight, the content of ethylene unit is 90 to 60
A resin composition (E) containing 10 to 50% by weight of an ethylene copolymer (C), which is 10% by weight, and 10 to 40% by weight of a petroleum resin (D). Stretch film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a stretch film for packaging comprising at least three layers. More specifically, the present invention relates to a stretch film for packaging which is excellent in flexibility and impact resistance and has transparency, deformation recovery property and cut property as a soft film comparable to a soft vinyl chloride film and a vinylon film.

[0002]

2. Description of the Related Art In recent years, a soft vinyl chloride film containing a plasticizer has been widely used as a soft film. However, the soft vinyl chloride resin has a social problem such as a transfer problem due to bleed-out of a plasticizer, an acid rain problem due to generation of hydrogen chloride during incineration, and generation of dioxin.

On the other hand, as a soft film similar to the above-mentioned soft vinyl chloride film, there is a film made of a polymer mainly composed of ethylene such as an ethylene-vinyl acetate copolymer, a low-density polyethylene and an ionomer. However, such a soft film made of a polymer mainly composed of ethylene is inferior to a soft vinyl chloride film in terms of transparency, haze, gloss, and the like, and also has difficulty in heat resistance and stiffness.

[0004] For this reason, for example, Japanese Patent Application Laid-Open No. Hei 5-14717
No. 4 discloses a crystalline olefin-based resin or a resin layer comprising 10 to 90% by weight of a crystalline olefin-based resin and 90 to 10% by weight of an olefin-based thermoplastic elastomer. Monomers 5 to 4 selected from vinyl acetate ester units, aliphatic unsaturated carboxylic acids, and aliphatic unsaturated monocarboxylic acid alkyl esters
There has been proposed a film obtained by inflation molding a film having a copolymer resin surface layer of 0% by weight laminated thereon at a blow ratio of 8 to 20 times. Also, Japanese Unexamined Patent Publication No.
No. 9 has at least one layer containing a propylene polymer and a petroleum resin, and has a storage elastic modulus (E ′) of 5.0 × at a frequency of 10 Hz and a temperature of 20 ° C. by dynamic viscoelasticity measurement. 10 ^{8 to} 5.0 × 10 ⁹ dyn / c
Stretch films for food packaging having m ² and loss tangent (tan δ) in the range of 0.2 to 0.8 have been proposed.
However, these films are flexible, deformable when the film on the tray is pressed with a finger, cut off when packaging plastic trays containing food with an automatic packaging machine, The impact resistance of the film when the tray was dropped was not all satisfactory.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a stretch film for packaging excellent in flexibility and impact resistance, and excellent in transparency, deformation recovery property and cutability.

[0006]

Means for Solving the Problems The present inventors have made intensive studies for the above purpose, and as a result, have found that both surface layers are composed of an ethylene-based polymer and at least one of the intermediate layers has a specific composition. -Based polymer, ethylene-based copolymer, and a resin composition formed by blending petroleum resins at a predetermined ratio, a film having at least three layers,
The present inventors have found that the above object has been achieved, and have completed the present invention.

That is, the present invention relates to a film comprising at least three layers, wherein both surface layers are composed of an ethylene polymer (A), and at least one of the intermediate layers comprises:
80 to 10% by weight of a propylene-based polymer (B) having a heat of fusion of 20 J / g or more and less than 80 J / g, and 10 to 50 of an ethylene-based copolymer (C) having an ethylene unit content of 90 to 60% by weight. % By weight and petroleum resins (D) 10
It is a packaging stretch film composed of a resin composition (E) containing 40% by weight. Hereinafter, the present invention will be described in detail.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The packaging stretch film of the present invention is a film having at least three layers composed of both surface layers and at least one intermediate layer. The ethylene polymer (A) used for the surface layer is a low-density polyethylene, a linear low-density polyethylene, a linear ultra-low-density polyethylene, a medium-density polyethylene, a high-density polyethylene, and a copolymer containing ethylene as a main component, , Ethylene and
Propylene, butene-1, pentene-1, hexene-
1, 3 or 10 carbon atoms such as heptene-1 and octene-1
Α-olefins; vinyl esters such as vinyl acetate and vinyl propionate; unsaturated carboxylic esters such as methyl acrylate, ethyl acrylate, methyl methacrylate, and ethyl methacrylate; and ionomers thereof; conjugated dienes and non-conjugated dienes Copolymers or multi-component copolymers with one or more comonomers selected from such unsaturated compounds, or compositions thereof. The ethylene unit content of the ethylene polymer is usually more than 50% by weight.

Among these ethylene polymers (A), low-density polyethylene, linear low-density polyethylene, linear ultra-low-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer and At least one ethylene-based polymer selected from ethylene-methacrylate copolymers is preferred. Examples of the acrylate include methyl acrylate and ethyl acrylate. Examples of the methacrylate include methyl methacrylate and ethyl methacrylate.

Further, among the ethylene polymers (A), an ethylene-vinyl acetate copolymer is more preferable, and an ethylene-vinyl acetate copolymer having a vinyl acetate unit content of 5 to 30% by weight is preferred. Most preferred.

The method for producing the ethylene polymer (A) is not particularly limited, and a known polymerization method using a known olefin polymerization catalyst, for example, Ziegler
Using a Natta type catalyst, a slurry polymerization method, a solution polymerization method,
A bulk polymerization method, a gas phase polymerization method, and the like, a bulk polymerization method using a radical initiator, and the like can be given.

The ethylene polymer (A) constituting the surface layer may contain various additives as required, for example, an antioxidant, an antifogging agent, an antistatic agent, a lubricant, a nucleating agent and the like. Can be.

The propylene polymer (B) used in the intermediate layer of the present invention is a propylene polymer having a heat of fusion of 20 J / g or more and less than 80 J / g as measured by a differential scanning calorimeter (DSC). Preferably, the heat of fusion is 30 to
It is a propylene polymer having a weight of 70 J / g. When the heat of fusion is less than 20 J / g, the heat resistance is poor. When it is more than 80 J / g, the heat resistance is excellent but the flexibility may be slightly inferior. The propylene unit content of the propylene-based polymer usually exceeds 50% by weight.

The heat of fusion was measured by a differential scanning calorimeter (DSC), the details of which will be described in the Examples section.

The propylene polymer (B) is a propylene homopolymer (B-1) or a propylene-α-olefin copolymer (B-1) having a propylene unit content of 100 to 50% by weight. No. Examples of the α-olefin include ethylene, butene-1, pentene-1, hexene-1, heptene-1, and octene-1.
And α-olefins having 2 to 4 carbon atoms, such as

The propylene polymer (B) may be a crystalline propylene homopolymer (B-1) having a propylene unit content of 100 to 90% by weight or a crystalline propylene-α-olefin copolymer. Coalescing (B-1)
A propylene-based resin composition containing 85 to 20% by weight, and 15 to 80% by weight of an amorphous polyolefin (B-2) having a propylene unit and / or butene-1 unit content of 50% by weight or more is preferable. . In the present invention, the term “amorphous” refers to a xylene-soluble component (FDA standard, CFR
21, §177.1520 (d) (4) (1)) is 40% by weight or more.

Specific examples of the amorphous polyolefin include polypropylene, polybutene-1, a propylene-ethylene copolymer, and butene-1 having a content of the propylene unit and / or butene-1 unit of 50% by weight or more. −
Ethylene copolymer, propylene-butene-1 copolymer,
Amorphous polyolefins such as propylene-butene-1-ethylene-terpolymer, propylene-hexene-1-ethylene-terpolymer, butene-1-hexene-1-ethylene-terpolymer and the like No.

The propylene polymer (B) is prepared by a known polymerization method using a known olefin polymerization catalyst, for example, a slurry polymerization method using a Ziegler-Natta type catalyst,
It can be produced by a solution polymerization method, a bulk polymerization method, a gas phase polymerization method, or the like.

The preparation method when the propylene polymer (B) is a polymer composition is not particularly limited, and may be a known method, for example, a kneader such as a kneader, a Banbury mixer, a roll, or the like. Alternatively, the heating and melting and kneading can be performed using a twin-screw extruder or the like. Further, various resin pellets may be dry-blended. Further, the polymer may be blended by multi-stage polymerization.

The ethylene copolymer (C) used in the intermediate layer of the present invention comprises ethylene and propylene, butene-1, pentene-1, hexene-1, heptene-1, octene-
Α-olefins having 3 to 10 carbon atoms such as 1; vinyl esters such as vinyl acetate and vinyl propionate; methyl acrylate, ethyl acrylate, methyl methacrylate;
Unsaturated carboxylic esters such as ethyl methacrylate;
And an ionomer thereof; a copolymer or a multi-component copolymer with one or more comonomers selected from unsaturated compounds such as conjugated dienes and non-conjugated dienes, or a composition thereof, comprising ethylene. Unit content is 90-
60% by weight.

When the ethylene unit content of the ethylene copolymer (C) exceeds 90% by weight, flexibility and impact resistance are poor, and when it is less than 60% by weight, heat resistance is poor. Further, the ethylene-based copolymer has a heat of fusion of 20 to 110 J.
/ G is preferable, and a copolymer having 30 to 100 J / g is more preferable.

Among these ethylene copolymers (C), linear low-density polyethylene, linear ultra-low-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer and ethylene-methacrylic copolymer At least one ethylene copolymer selected from acid ester copolymers is preferred. As the acrylic acid ester and the methacrylic acid ester, those mentioned above for the ethylene polymer (A) are similarly used.

Further, among the above ethylene copolymers (C), an ethylene-vinyl acetate copolymer is particularly preferred.

The method for producing the ethylene copolymer (C) is not particularly limited, and a known polymerization method using a known olefin polymerization catalyst, for example, Ziegler
Using a Natta type catalyst, a slurry polymerization method, a solution polymerization method,
A bulk polymerization method, a gas phase polymerization method, and the like, a bulk polymerization method using a radical initiator, and the like can be given.

Petroleum resins (D) used in the intermediate layer of the present invention
Examples thereof include a rosin resin, a terpene resin, a petroleum resin or a hydrogenated product thereof, a cumarone-indene resin, and an alkyl-phenol resin. Rosin-based resin is a resin mainly composed of abietic acid or a derivative thereof obtained from pine resin or the like.For example, gum rosin, wood rosin, hydrogenated rosin, esterified rosin esterified with alcohol, phenol and rosin A rosin phenol resin reacted is exemplified. Terpene-based resin is a resin made from turpentine oil, for example, α
-Terpene resin in which pinene and β-pinene are polymerized, terpene phenol resin in which phenol and terpene are reacted,
Aromatic modified terpene resin provided with polarity with styrene or the like,
And hydrogenated terpene resins. A petroleum resin or a thermoplastic resin obtained by polymerizing a cracked oil fraction produced by pyrolysis of petroleum solidification and its hydrogenated product, for example, aliphatic petroleum resins obtained by the C ₅ fraction as a raw material, C Aromatic petroleum resin derived from ₉ fractions, alicyclic petroleum resin derived from dicyclopentadiene, copolymerized petroleum resin obtained by copolymerizing two or more of these, and hydrogenation of these Series petroleum resin and the like. Coumarone-indene resin is a resin composed of a polymer containing coumarone and indene as main components. An alkyl-phenol resin is a resin obtained by reacting an alkylphenol with an aldehyde. Specifically, commercial products such as Heylets and Petrozine manufactured by Mitsui Petrochemical Industries, Ltd., Alcon manufactured by Arakawa Chemical Industries, Ltd., Clearon manufactured by Yashara Chemical Co., Ltd., and Escolets manufactured by Tonex Corporation are used. Can be.

Among the petroleum resins (D), hydrogenated derivatives such as hydrogenated rosin, hydrogenated terpene resin, and hydrogenated petroleum resin are preferable in terms of color tone and odor.

The resin composition (E) used in the intermediate layer of the present invention
Is 80 to 10% by weight of the propylene-based polymer (B),
10 to 50% by weight of the ethylene-based copolymer (C) and
It is a resin composition containing 10 to 40% by weight of petroleum resins (D). When the proportion of the propylene-based polymer (B) is more than 80% by weight, the flexibility is lowered, and when it is less than 10% by weight, the heat resistance is lowered, which is not preferable. On the other hand, if the proportion of the ethylene-based copolymer (C) is less than 10%, flexibility and impact resistance decrease, and if it exceeds 50% by weight, heat resistance decreases, which is not preferable. If the proportion of the petroleum resin (D) is less than 10% by weight, the cut property of the film is lowered, and
If the content is more than 10% by weight, the impact resistance of the film is undesirably reduced. In particular, the propylene-based polymer (B) 65
Resin composition (E) containing -30% by weight, 20-40% by weight of ethylene copolymer (C) and 15-35% by weight of petroleum resin (D) is excellent in flexibility and impact resistance It is preferable from the viewpoint of balance with the cut property, the deformation recovery property and the transparency.

The method for preparing the resin composition (E) used in the present invention is not particularly limited, and known methods, for example, a kneader such as a kneader, a Banbury mixer, a roll, a single-screw or twin-screw extruder, and the like. And heat-melting and kneading. Further, various resin pellets may be dry-blended.

Further, the resin composition (E) constituting the intermediate layer
Can contain various additives and fillers, if necessary, for example, an antioxidant, an antifogging agent, an antistatic agent, a nucleating agent, a flame retardant and the like. Further, other resins can be blended and used within a range not to hinder the present invention.
For example, a recycled resin can be blended.

In the stretch film for packaging of the present invention, a recycled resin layer may be laminated and inserted in the intermediate layer, and another thermoplastic resin layer, for example, a gas barrier is provided, as long as the object of the present invention is not impaired. Therefore, a polyamide resin, an ethylene / vinyl alcohol copolymer, a polyester resin or the like may be laminated and inserted. Further, in order to increase the adhesive strength between the layers, an adhesive or an adhesive resin layer may be laminated and inserted.

The thickness of each layer constituting the stretch film for packaging of the present invention is not particularly limited and can be arbitrarily selected. Usually, each layer is about 2-100μ
m. Also, the thickness ratio of both surface layers to the total thickness of the film is not particularly limited, and can be arbitrarily selected. Usually, the total thickness of both surface layers is configured to be 20 to 90% of the thickness of the laminated film.

The method for producing the stretch film for packaging of the present invention is not particularly limited, and may be a known method, for example,
Co-extrusion laminating method by inflation method or casting method,
Extrusion lamination, sand lamination, dry lamination, and the like can be used.

If the packaging stretch film of the present invention requires shrinkage, it is preferably stretched in at least one direction after film formation. Stretching can be uniaxial or biaxial. In the case of uniaxial stretching, for example, a commonly used roll stretching method is preferable. In the case of biaxial stretching, for example, a sequential stretching method in which biaxial stretching is performed after uniaxial stretching may be used, or a simultaneous biaxial stretching method such as tubular stretching may be used.

[0034]

As described in detail above, according to the present invention,
It is possible to provide a packaging stretch film which is excellent in flexibility and impact resistance and has good deformation recovery properties, cut properties and transparency. Further, the stretch film for packaging of the present invention is a soft film, and can be applied to various uses instead of the soft vinyl chloride film which is a social problem due to environmental pollution.

[0035]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

First, methods for measuring physical properties in the following Examples and Comparative Examples will be described. (1) Ethylene Unit Content The measurement was carried out by ¹³ C-NMR method according to the method described on pages 615 to 616 of a Polymer Analysis Handbook (1995, published by Kinokuniya Bookstore). (2) Content of Propylene Unit and Butene-1 Unit The measurement was carried out by the ¹³ C-NMR method according to the method described on pages 615 to 619 of a handbook for polymer analysis (1995, published by Kinokuniya Bookstore). (3) Melt flow rate (MFR) In accordance with JIS K7210, measurement was made according to Condition 4 in Table 1 for ethylene polymers and according to Condition 14 in Table 1 for propylene polymers.

(4) Content of Vinyl Acetate Unit The content was measured according to JIS K6730. (5) Heat of fusion of propylene-based polymer (B) Using an RDC220 manufactured by Seiko Denshi Kogyo Co., Ltd., about 5 mg of a sample was packed in an aluminum pan, and the temperature was raised to 230 ° C at 100 ° C / min. , The temperature was lowered to -50 ° C at 10 ° C / min, and the temperature was maintained at -50 ° C for 5 minutes, and then the temperature was raised to 230 ° C at 10 ° C / min, and the melting curve was measured. The point at which the melting curve returns to the base line on the high temperature side and the point at 0 ° C. of the melting curve were connected by a straight line, and the heat of fusion was determined from the total area of the portion surrounded by the straight line and the melting curve. (6) Heat of fusion of ethylene copolymer (C) As an apparatus, RDC220 manufactured by Seiko Denshi Kogyo KK was used, and about 5 mg of a sample was packed in an aluminum pan and heated to 150 ° C at 100 ° C / min. After maintaining at 5 ° C. for 5 minutes, the temperature was lowered to −100 ° C. at 10 ° C./min, and after maintaining at −100 ° C. for 5 minutes, the temperature was raised to 200 ° C. at 10 ° C./min, and a melting curve was measured. The base line on the high temperature side of the melting curve was extended linearly to the low temperature side, and the heat of fusion was determined from the total area of the straight line and the portion surrounded by the melting curve.

(7) Rigidity (1% SM) A 120 mm × 20 mm strip-shaped film test piece having a longitudinal direction in the take-up direction (MD) and a direction perpendicular to the take-up direction (TD) of a film is gripped with a distance of 60 mm. Tensile speed 5m
It was pulled at m / min and the stress at 1% elongation was measured. (8) Transparency (haze) Measurement was performed according to ASTM D1003. (9) Cutability When packaging a styrene foam tray using a commercially available push-up type tray automatic wrapping machine (AW2600AT-III.PE manufactured by Teraoka Seiko Co., Ltd.), breakage of the broken film after cutting the film with a saw blade. Was determined as follows. ：: Very good without folding of the film. Δ: The film is slightly broken but good. X: The film is folded.

(10) Deformation recovery degree A circular sample film 1 having a diameter of 44.45 mm is fixed to a film fixing jig 2, and the tip of the film has a radius of 6.3 at the center of the film.
Using a load cell 4, push a 5 mm hemispherical pin 3 to a predetermined depth 5 at a speed of 100 mm / min, immediately pull it up at the same speed, and measure whether the push completely disappears within 30 seconds. did. The maximum indentation depth 5 at which the pressure disappears completely after the pressing was defined as the degree of deformation recovery. FIG. 1 is a plan view of an apparatus for measuring the degree of deformation recovery. (11) Impact strength Using a film impact tester manufactured by Toyo Seiki Seisaku-sho, the penetrating tip of the pendulum has a semicircular shape of 15 mmφ,
The area of the effective test piece was made into a circle of 50 mmφ, and the impact hole punching strength of the film at 23 ° C. was measured.

Example 1 [Preparation of Surface Layer Resin Composition] As the resin composition constituting the surface layer, ethylene-vinyl acetate copolymer (A) (M
FR (190 ° C.) = 2 g / 10 min, content of vinyl acetate unit = 15.8% by weight) 98% by weight, antifogging agent (STO-405 manufactured by Marubishi Yuka Kogyo Co., Ltd.) 2% by weight A resin composition prepared by melt-kneading with a mixer was used. [Preparation of Intermediate Layer Resin Composition] As the resin composition constituting the intermediate layer, a propylene-ethylene random copolymer which is a crystalline propylene-α-olefin copolymer (B-1) (Sumitomo Chemical Co., Ltd. Noblen WF732-
1. MFR (230 ° C.) = 5.5 g / 10 min, propylene unit content = 97% by weight) 50% by weight, amorphous polyolefin (B-2) (Ube Tack UT2780 manufactured by Ube Lexen Co., Ltd., melt viscosity) (190 ° C.) = 8000 cp
s, propylene unit content = 65% by weight, butene-1
Unit content = 35% by weight) 50% by weight of a propylene-based resin composition (B) having a melting heat of 57 J / g obtained by melting and kneading 50% by weight with a Banbury mixer, and an ethylene-vinyl acetate copolymer (C). (MFR (190 ° C.) = 2 g /
10 minutes, 30% by weight of vinyl acetate unit content = 15.8% by weight, heat of fusion = 85 J / g) and petroleum resins (D)
(Alcon P125 manufactured by Arakawa Chemical Industries, Ltd.) 20% by weight
And a resin composition prepared by melt-kneading with a single screw extruder. [Production of Film] A 13 μm-thick two-layer three-layer laminated film having a surface layer / intermediate layer / surface layer composition ratio of 38/24/38 was processed at a processing temperature of 200 using a Placo three-layer blown film processing machine. C. and a blow-up ratio of 4.5. Table 1 shows the evaluation results of the obtained films.
And Table 2.

COMPARATIVE EXAMPLE 1 The same propylene resin composition (B) as used in Example 1 was used as the resin composition for forming the intermediate layer (80% by weight).
And the same petroleum resin (D) 20 as used in Example 1.
A laminated film was formed in the same manner as in Example 1, except that a resin composition prepared by melt-kneading the resin composition in a single-screw extruder was used. Table 1 and Table 2 show the evaluation results of the obtained films.
Shown in

Comparative Example 2 A laminated film was produced in the same manner as in Example 1 except that 100% by weight of the same propylene resin composition (B) as used in Example 1 was used as the resin composition constituting the intermediate layer. Molded. Tables 1 and 2 show the evaluation results of the obtained films.

[0043]

[Table 1] In the table, EVA: ethylene-vinyl acetate copolymer (A) or (C) PP: propylene-based resin composition (B) C-PP: crystalline propylene-α-olefin copolymer (B-1) APO: Amorphous polyolefin (B-2) STO-405: Anti-fogging agent (STO manufactured by Marubishi Yuka Kogyo Co., Ltd.)
-125) P125: Petroleum resins (D) (Alcon P125 manufactured by Arakawa Chemical Industry Co., Ltd.)

[0044]

[Table 2]

[Brief description of the drawings]

FIG. 1 is a plan view of an apparatus for measuring a degree of deformation recovery of a film.

[Description of Signs] 1 ... Circular sample film, 2 ... Film fixing jig, 3 ... Pin 4 ... Load cell, 5 ... Indentation depth

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 23/10 C08L 23/10 55/00 55/00

Claims (7)

[Claims] 1. A film comprising at least three layers, wherein both surface layers are composed of an ethylene polymer (A), and at least one of the intermediate layers has a heat of fusion of 20 J / g.
Propylene-based polymer (B) 8 having a content of not less than 80 J / g
0 to 10% by weight, 10 to 50% by weight of an ethylene copolymer (C) having an ethylene unit content of 90 to 60% by weight
A stretch film for packaging, comprising a resin composition (E) containing 10 to 40% by weight of a petroleum resin (D). 2. The stretch film for packaging according to claim 1, wherein the petroleum resin (D) is a petroleum resin or a hydrogenated product thereof. 3. An ethylene-based polymer (A) comprising low-density polyethylene, linear low-density polyethylene, linear ultra-low-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer, and ethylene- The stretch film for packaging according to claim 1 or 2, wherein the stretch film is at least one ethylene polymer selected from methacrylate copolymers. 4. The stretch film for packaging according to claim 3, wherein the ethylene polymer (A) is an ethylene-vinyl acetate copolymer. 5. A propylene homopolymer (B-1) or a propylene-α-olefin copolymer (B-1) wherein the propylene polymer (B) has a propylene unit content of 100 to 50% by weight. The stretch film for packaging according to claim 1 or 2, which is: 6. The propylene polymer (B) is a crystalline propylene homopolymer (B-1) or a crystalline propylene polymer having a propylene unit content of 100 to 90% by weight.
85 to 20% by weight of an α-olefin copolymer (B-1) and 15 to 80% by weight of an amorphous polyolefin (B-2) having a content of propylene units and / or butene-1 units of 50% by weight or more. The stretch film for packaging according to claim 1 or 2, which is a propylene-based resin composition containing 0.1% by weight. 7. An ethylene copolymer (C) comprising ethylene-
3. The stretch film for packaging according to claim 1, which is a vinyl acetate copolymer.