JP2002294083A - Resin composition and use thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition suitable for obtaining films composed of a hydrocarbon resin having excellent anti-fogging properties and the films composed of the hydrocarbon resin having the excellent anti-fogging properties. SOLUTION: This resin composition comprises the hydrocarbon resin and a surfactant which is composed of the following (X) and (Y) in a weight ratio of (80:20) to (10:90). (X) a surfactant composed of an ester of diglycerol with an 8-22C fatty acid and (Y) a surfactant having a repeating unit derived from ethylene oxide in the molecule.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a resin composition and its use. More specifically, the present invention relates to a resin composition which is required as an antifogging film, particularly to a resin composition suitable as a film for stretch packaging and its use.

[0002]

2. Description of the Related Art The demand for films and sheets made of resin is increasing year by year. Among such films and sheets, as a film or sheet used for stretch packaging of meat, fish and shellfish, vegetables, fruits and the like, a vinyl chloride resin has been mainly used. In recent years, due to safety and hygiene issues and increasing awareness of the global environment, development of resin compositions in which antifogging agents are blended with hydrocarbon resins such as low-density polyethylene in place of conventional vinyl chloride resins has been developed. (For example, Japanese Patent Application Laid-Open No. H5-222225)
No. 2, JP-A-9-295354, JP-A-10-295354
-60191).

[0003]

However, conventionally known films made of hydrocarbon resins are still insufficient in antifogging properties. An object of the present invention is to provide a resin composition suitable for obtaining a film made of a hydrocarbon resin having excellent antifogging properties, and to provide a film made of a hydrocarbon resin having excellent antifogging properties. is there.

[0004]

The present invention comprises a hydrocarbon resin and a surfactant, wherein the surfactant has a weight ratio of the following (X) to the following (Y) of 80:20 to 10:
The object of the present invention is to solve the above problem by using a resin composition which is 90 as a surfactant and films made of the resin composition. (X) a surfactant comprising an ester of diglycerin and a fatty acid having 8 to 22 carbon atoms. (Y) A surfactant having a repeating unit derived from ethylene oxide in the molecule. In addition, although the film and the sheet are distinguished by the thickness,
In the present invention, these are collectively referred to as films. Hereinafter, the present invention will be described in detail.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The hydrocarbon resin used in the present invention means a thermoplastic resin comprising a hydrocarbon, and is obtained by polymerizing a monomer containing no non-hydrocarbon monomer (for example, acrylate). It is a thermoplastic resin.
Representative examples of the hydrocarbon resin include a thermoplastic resin obtained by polymerizing an unsaturated hydrocarbon compound, and an ethylene polymer resin or a propylene polymer resin is preferable.

The above-mentioned ethylene polymer resin means a thermoplastic resin obtained by polymerizing ethylene. Ethylene homopolymer or ethylene containing 80 mol% or more of repeating units derived from ethylene and carbon 3 atoms
Copolymers with an α-olefin of 18 or copolymers of ethylene with at least one other monomer are preferred. Propylene, 1-butene as the α-olefin,
Examples thereof include 4-methyl-1-pentene, 1-hexene, 1-octene, and 1-decene. Conjugated dienes (such as butadiene and isoprene) as the other monomer
And non-conjugated dienes (e.g., 1,4-pentadiene).

Examples of the ethylene polymer resin include ultra low density polyethylene; low density polyethylene; medium density polyethylene; high density polyethylene; ethylene-propylene copolymer, ethylene-1-butene copolymer, and ethylene-4-
Ethylene such as methyl-1-pentene copolymer, ethylene-1-hexene copolymer, ethylene-1-octene copolymer, ethylene-1-decene copolymer and the like and having 3 carbon atoms
Copolymers with ethylene and conjugated dienes (such as butadiene and isoprene); and ethylene and non-conjugated dienes (such as 1,4-
(Pentadiene). As the ethylene polymer resin, an ethylene polymer resin having a polyethylene crystal structure is more preferable.

[0008] The propylene polymer resin is
Means a thermoplastic resin obtained by polymerizing propylene,
A thermoplastic propylene polymer resin containing at least 80 mol% of a repeating unit derived from propylene is preferable, and a propylene homopolymer, propylene and an α-olefin having 2 to 10 carbon atoms (excluding propylene)
Or a copolymer of propylene and at least one other monomer. Examples of the α-olefin include ethylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene, and 1-decene. As other monomers, conjugated dienes (for example, butadiene and isoprene) can be exemplified. As the propylene polymer resin, a propylene polymer resin having an isotactic polypropylene crystal structure is more preferable.

The hydrocarbon resin used in the present invention is more preferably an ethylene polymer resin.
Copolymers with olefins (ethylene-α-olefin copolymers) are more preferred. When the resin composition of the present invention using such an ethylene-α-olefin copolymer is used as a film for stretch packaging, it is excellent in anti-fogging properties and can be used for foods having a sharp corner or a sharp portion of a tray. It is excellent in mechanical properties such that it is not easily torn when packaging. As the α-olefin of the ethylene-α-olefin copolymer, an α-olefin having 3 to 18 carbon atoms is preferable.

If the hydrocarbon resin used in the present invention is an ethylene-α-olefin copolymer (A) having the following properties (a1) and (a2), the mechanical properties are further improved. ,preferable. (A1) The composition distribution variation coefficient (Cx) shown in the following equation 1 is 0.5 or less. (A2) The content of the repeating unit derived from ethylene is 80 mol% or more. Cx = σ / SCBave (Equation 1) σ: Standard deviation of composition distribution (1 / 1000C) SCBave: Average value of short-chain branching per 1000C (1 / 1000C)

The composition distribution variation coefficient (Cx) in (a1) is 0.5 or less, preferably 0.4 or less.
More preferably, it is 0.3 or less. If the composition distribution variation coefficient (Cx) is too large, the resulting films are likely to be easily blocked, which is not preferable.

The content of the repeating unit derived from ethylene in the above (a2) is at least 80 mol%, preferably at least 90 mol%. If the content of the repeating unit derived from ethylene is too small, the mechanical strength of the obtained films is undesirably reduced.

As the α-olefin, for example, propylene, 1-butene, 1-pentene, 1-hexene, 4-
A single or combined use of methyl-1-pentene, 1-octene and the like can be mentioned. Of these α-olefins,
Α-olefins having 4 or more carbon atoms are preferred,
1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene and the like are preferable from the viewpoint of easy availability of monomers and the quality of the obtained copolymer.

For the purpose of imparting molding stability to the ethylene-α-olefin copolymer (A), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), ultra-low-density polyethylene ( VLDP
E), high density polyethylene (HDPE); propylene polymer, propylene-ethylene copolymer, propylene-butene-1 copolymer, propylene-ethylene-butene-1
Copolymers (random copolymers, block copolymers), etc.
And a mixture thereof may be blended, and it is particularly preferable to blend a low density polyethylene (LDPE).

The low-density polyethylene is obtained by polymerizing ethylene using a free radical generator such as an organic peroxide or oxygen. The polymerization reaction is usually 1
Under a polymerization temperature of 30 to 300 ° C., 500 to 3000 kg /
It is carried out under a polymerization pressure of cm ² . When the low-density polyethylene is used, the hydrocarbon resin of the present invention comprises the ethylene-α-olefin copolymer (A) and the low-density polyethylene (B), and the weight of (A) and (B) Mixtures having a ratio between 40:60 and 99: 1 are preferred.

The low-density polyethylene (B) includes J
MFR by IS-K6760 is usually 0.1 to 100 g
/ 10 min, preferably 0.5 to 50 g / min, more preferably 1.0 to 10 g / 10 min and a density of usually 0.910
What is 0.930 g / cm < ³ > is used.

The content of the low-density polyethylene (B) in the mixture is from 1 to 60% by weight, preferably from 5 to 55% by weight, more preferably from 10 to 60% by weight of the total amount with the (A).
-50% by weight, more preferably 15-40% by weight. When the content is within this range, the cutability in automatic packaging, the bubble stability during inflation molding, and the mechanical strength and low-temperature sealability are excellent.

The surfactant used in the present invention comprises the following (X) and (Y), and the weight ratio of (X) to (Y) is 80:20 to 10:90, preferably 60:20.
40 to 40:60. When the weight ratio is within this range, the antifogging property is excellent, and it is preferable. The hydrocarbon resin used in the present invention comprises the ethylene-α-olefin copolymer (A), the (A) and the low-density polyethylene (B), and the weight ratio between (A) and (B) is 40: 60-9
In the case of a mixture having a ratio of 9: 1, it is preferable that the weight ratio is within this range because the antifogging property is particularly excellent. (X) a surfactant comprising an ester of diglycerin and a fatty acid having 8 to 22 carbon atoms. (Y) A surfactant having a repeating unit derived from ethylene oxide in the molecule.

The surfactant (X) can be synthesized by a known method. Fatty acids that react with diglycerin may be used alone or as a mixture of two or more. Although the reaction molar ratio of diglycerin and fatty acid can be appropriately selected, one obtained by reacting 1 to 2 mol of fatty acid with respect to 1 mol of diglycerin is preferable. In the present invention, for example, a compound obtained by reacting 1 mol of diglycerin and 1 mol of oleic acid is called diglycerin monooleate, and is obtained by reacting 1 mol of diglycerin with 1.5 mol and 2 mol of oleic acid. These compounds are called diglycerin sesquiolate and diglycerindiolate, respectively. Therefore, what is called diglycerin monooleate includes not only monoesters but also diesters and triesters.

Examples of the surfactant (X) include diglycerin monooleate, diglycerin monolaurate, diglycerin monostearate, diglycerin monopalmitate, diglycerin monobehenate, diglycerin sesquiolate, and diglycerin sesquilau. Rate, diglycerin sesquistearate, diglycerin sesquipalmitate, diglycerin sesquibehenate, diglycerindiolate, diglycerin dilaurate, diglycerin distearate, diglycerin dipalmitate, diglycerin dibehenate, triglycerin Monooleate, triglycerin monolaurate, triglycerin monostearate, triglycerin monopalmitate, triglycerin monobehenate, triglycerin sesquiolate, triglycerin Laurate, triglycerin sesquistearate, triglycerin sesquipalmitate, triglycerin sesquibehenate, triglycerindiolate, triglycerin dilaurate, triglycerin distearate, triglycerin dipalmitate, triglycerin dibehenate, tetraglycerin Monooleate, tetraglycerin monolaurate, tetraglycerin monostearate, tetraglycerin monopalmitate, tetraglycerin monobehenate, tetraglycerin sesquiolate, tetraglycerin sesquilaurate, tetraglycerin sesquistearate, tetraglycerin sesquipalmitate, Tetraglycerin sesquibehenate, tetraglycerindiolate, tetraglycerin dilaurate, tetraglycerin di Teareto,
Tetraglycerin dipalmitate, tetraglycerin dibehenate, etc., and one or two of these
It is preferable to use a mixture of two or more kinds, and among them, diglycerin monooleate or diglycerin monolaurate is preferable.

Examples of the surfactant (Y) include polyoxyethylene lauryl ether, polyoxyethylene oleyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl phenyl ether,
Polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ether, polyethylene glycol oleate, polyethylene glycol laurate, polyethylene glycol stearate, polyoxyethylene glycerin laurate, polyoxyethylene glycerin oleate, polyoxy Ethylene sorbitan oleate, polyoxyethylene sorbitan laurate, polyoxyethylene sorbitan stearate, polyoxyethylene sorbitan oleyl ether, polyoxyethylene sorbitan lauryl ether, polyoxyethylene sorbitan stearyl ether, and the like. Used as a mixture of one or more of It is preferred.

In the resin composition of the present invention, the content of the surfactant is from 0.1 to 20% by weight of the whole resin composition.
And more preferably 0.5 to 10% by weight. If the content is excessive, the film may become sticky and adversely affect heat sealability and the like. If the content is too small, the antifogging property may deteriorate, which is not preferable.

In the resin composition of the present invention, various additives and fillers such as antioxidants, nucleating agents,
An ultraviolet absorber, a lubricant, an anti-blocking agent and the like can be included. Furthermore, other resins may be blended and used within a range not to hinder the present invention. For example, recycled resin generated from trimming loss, etc.,
A petroleum resin or a hydrogenated product thereof can be blended for the purpose of improving self-adhesion.

The method for producing the resin composition of the present invention is not particularly limited, and may be a known method, for example, a kneader,
Kneaders such as Banbury mixers and rolls, 1 shaft or 2
There is a method in which the raw material resin is heated and melt-kneaded using a screw extruder or the like and mixed with a surfactant or the like. Also,
A masterbatch containing a surfactant or the like at a high concentration may be manufactured in advance, and the resin pellets as a raw material and the masterbatch containing a surfactant or the like may be dry-blended.

The resin composition of the present invention may be used as at least one layer of a multilayer film. As other layers,
A layer made of a thermoplastic resin or a thermoplastic resin composition is preferable, and a layer made of an olefin-based thermoplastic resin or an olefin-based thermoplastic resin composition is more preferable. Specifically, low density polyethylene (LDPE); linear low density polyethylene (LLDPE); very low density polyethylene (VLDPE); high density polyethylene (HDPE);
Ethylene copolymers, for example, ethylene-vinyl acetate copolymer (EVA), its saponified product (EVOH), ethylene-ethyl acrylate copolymer (EEA),
Methyl methacrylate copolymer (EMMA), ethylene-
Glycidyl methacrylate copolymer (EGMA), ethylene-maleic anhydride copolymer (EMAH), ionomer resin; propylene homopolymer; propylene-ethylene copolymer; propylene-1-butene copolymer; propylene-ethylene- Examples thereof include 1-butene copolymers (random copolymers and block copolymers) and the like, and mixtures thereof.

As a method for producing films using the resin composition of the present invention, for example, inflation method, T
It can be manufactured using a generally known method such as a die method.

As a method for producing a multilayer film using the resin composition of the present invention, it is possible to employ a generally known method such as a coextrusion method or an extrusion lamination method.

In the present invention, the thickness of the films is not particularly limited and can be arbitrarily selected. The thickness of the films of the present invention is usually in the range of 2 to 1000 μm, preferably 5 to 200 μm, more preferably 5 to 50 μm, and particularly preferably 5 to 30 μm.

In the present invention, the thickness of the multilayer films is not particularly limited and can be arbitrarily selected. The thickness of the multilayer film of the present invention is usually 2 to 1000.
μm, preferably 5 to 200 μm, more preferably 5 to 50 μm, and particularly preferably 5 to 30 μm.
It is.

The films of the present invention are suitable as films for stretch packaging. The thickness of the film for stretch packaging of the present invention is usually in the range of 2 to 100 μm, preferably 5 to 50 μm, more preferably 5 to 30 μm, and particularly preferably 5 to 20 μm.

The multilayer films of the present invention are particularly suitable as films for stretch packaging. The stretch packaging film comprising the multilayer film of the present invention has a thickness of usually 2 to 100 μm, preferably 5 to 50 μm, more preferably 5 to 30 μm, and particularly preferably 5 to 20 μm.

In the present invention, when the films need to be shrinkable, it is preferred that the film is formed and then stretched in at least one direction. 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 method in which biaxial stretching is performed simultaneously, such as tubular stretching, is also possible.

[0033]

Hereinafter, the present invention will be described based on examples.
The present invention is not limited to these examples unless it goes beyond the gist. First, methods for measuring physical properties in the following examples and comparative examples will be described.

(1) Coefficient of variation in composition distribution (Cx) Measured by using a temperature rising elution fractionation apparatus (TREF) manufactured by Tosoh Corporation. The ethylene-α-olefin copolymer was dissolved in an orthodichlorobenzene (ODCB) solvent heated to 145 ° C. and adjusted to a concentration of 0.01 g / ml to prepare a measurement sample. 1
10 ml of the measurement sample was poured into a column (sea sand filled with a length of 150 mm, an inner diameter of 21 mm, and 50 to 80 mesh) set in a column oven heated to 45 ° C. The temperature of the oven was lowered at a rate of 40 ° C./45 minutes to 105 ° C., from 105 ° C. to −15 ° C. over 8 hours, and kept at −15 ° C. for 4 hours. Then, add OD to the column.
10 ° C./6 while flowing CB at a rate of 2.5 ml / min.
The temperature was raised at a rate of 0 minutes and raised to 125 ° C., during which the relative concentration of the measurement sample eluted from the column was measured by FT-IR connected to the column. FT-IR measurement is -14
To 110 ° C every 2 ° C.
The area of the absorption peak at 2780 cm ^-1 was used. Carbon 10 of ethylene-α-olefin copolymer eluted at each temperature
The degree of short-chain branching (SCB) per 00 was determined by the following formula (5).
Determined by However, at the temperature where SCB was negative in calculation, no elution was made. SCB = −0.7322 × elution temperature (° C.) + 70.68 (Equation 5) A composition distribution curve was obtained from the obtained degree of short-chain branching and its relative concentration. The degree (SCBave) and the standard deviation (σ) of the composition distribution were obtained, and the composition distribution variation coefficient Cx representing the width of the distribution was calculated from the following (Equation 1). Cx = σ / SCBave (Equation 1) Average degree of short-chain branching (SCBave) = ΣN (i) · W
(I) N (i): Degree of short-chain branching at the i-th data sampling point W (i): Relative density at the i-th data sampling point ｛Σ (N (i) -SCBave)
²・ W (i)｝ ^0.5

(2) Ethylene-α-olefin copolymer
Including repeating units derived from ethylene in isomer (A)
Amount: Polymer Analysis Handbook (1995, Kinokuniya
Listed on pages 593-594 of the bookstore)
In accordance with the law, cited document (9)
3, the characterization and properties of macromolecules)
And about 1378cm ^-1Near and 1303cm^-1Infrared absorption of
The yield strength was measured and determined.

(3) Melt flow rate (MFR) of low density polyethylene (B): Measured according to the method specified in JIS K6760.

(4) Density of low-density polyethylene (B): According to the method specified in JIS K6760. 1
The measurement was performed after annealing for 1 hour in boiling water at 00 ° C.

(5) Anti-fogging property: As shown in FIG. 1, a resin container was filled with water at 23 ° C. so as to have a depth of 10 mm, and a polyvinyl chloride cylinder covered with a sample film was placed in the container. The sample was placed in a thermo-hygrostat adjusted to ° C. The state after 3 minutes from the introduction of the thermostatic chamber was evaluated, and a five-step evaluation was performed based on the following criteria. The higher the value, the better the anti-fog property. (Evaluation criteria) 5: A uniform water film is formed, and the visibility is good. 4: There is slight disturbance in the water film, and the feeling of see-through is poor. 3: Disturbance in the water film 2: Many water droplets adhered, resulting in poor see-through feeling. 1: Clouding occurs and cannot be seen through.

(6) Mechanical strength (Elmendorf tear strength): According to the method specified in ASTM D882,
It was measured for MD (film forming direction) / TD (direction perpendicular to the film forming direction).

Example 1 Exelene F manufactured by Sumitomo Chemical Co., Ltd. as an ethylene-α-olefin copolymer (A)
X (CX2001) [Cx = 0.25, content of repeating units derived from ethylene = 95 mol%] 80 parts by weight, Sumikasen (CE2575) manufactured by Sumitomo Chemical Co., Ltd. as low density polyethylene (B) [ MFR = 2 g /
10 minutes, 20 parts by weight of density = 923 kg / m ³ ], surfactant (X) [diglycerin monooleate manufactured by Sakamoto Yakuhin Co., Ltd.] and surfactant (Y) [polyethylene glycol laurin manufactured by Sakamoto Yakuhin Co., Ltd.] Acid ester] in a weight ratio of 50:50, and 0.25 parts by weight of a surfactant were mixed and melt-kneaded with a Banbury mixer to prepare a resin composition. The resin composition was prepared with a die diameter of 150 mm and a die lip of 2.0 mm.
Is supplied to an inflation film forming machine manufactured by Placo Co., Ltd.
A film having a thickness of 20 μm was produced by inflation molding at 0 ° C., a blow ratio of 1.8, and a take-up speed of 20 m / min. Table 1 shows various characteristic values of the obtained film.

Example 2 In Example 1, the surfactants were (X) [diglycerin monooleate manufactured by Sakamoto Yakuhin Co., Ltd.] and (Y-1) [polyethylene glycol lauric acid manufactured by Sakamoto Yakuhin Co., Ltd.] Ester) and (Y-2) [polyoxyethylene lauryl ether manufactured by Sakamoto Yakuhin Co., Ltd.]
A film having a thickness of 20 μm was produced in the same manner as in Example 1, except that the surfactant was added in a weight ratio of 0:25:25. Table 1 shows various characteristic values of the obtained film.

Comparative Example 1 The procedure of Example 1 was repeated, except that the surfactant was changed to only (X) [diglycerin monooleate manufactured by Sakamoto Yakuhin Co., Ltd.]. A film was produced. Table 1 shows various characteristic values of the obtained film.

Comparative Example 2 In Example 1, the surfactants were (X) [diglycerin monooleate manufactured by Sakamoto Yakuhin Co., Ltd.] and (Y-1) [polyethylene glycol lauric acid manufactured by Sakamoto Yakuhin Co., Ltd.] Ester) and (Y-2) [polyoxyethylene lauryl ether manufactured by Sakamoto Yakuhin Co., Ltd.]
A film having a thickness of 20 μm was produced in the same manner as in Example 1, except that the surfactant was mixed in a weight ratio of 5: 7.5: 7.5. Table 1 shows various characteristic values of the obtained film. Table 1 shows various characteristic values of the obtained film.

[0044]

[Table 1]

[0045]

As described in detail above, according to the present invention,
A resin composition suitable for obtaining a film composed of a hydrocarbon resin having excellent antifogging properties → hydrocarbon resin, and a film composed of a hydrocarbon resin having excellent antifogging properties → hydrocarbon resin are provided. You. According to the present invention, it is possible to obtain films having excellent antifogging properties while maintaining the mechanical strength, and such films are particularly suitably used as films for stretch packaging.

[Brief description of the drawings]

FIG. 1 is a schematic view of an apparatus used for evaluating anti-fogging property in Examples.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 71/02 C08L 71/02 F-term (Reference) 3E086 AB01 AD16 BA04 BA15 BA40 BB66 BB90 CA01 4F071 AA15 AA16 AA17 AA18 AC10 AE10 AH04 BB09 BC01 BC12 4J002 BB041 BB051 BB151 CH022 EH046 EH047 FD312 FD316 FD317 GG02

Claims (7)

[Claims] 1. A surfactant containing a hydrocarbon resin and a surfactant, wherein the surfactant has a weight ratio of the following (X) to the following (Y) of 80:20 to 10:90. A resin composition comprising: (X) a surfactant comprising an ester of diglycerin and a fatty acid having 8 to 22 carbon atoms. (Y) A surfactant having a repeating unit derived from ethylene oxide in the molecule. 2. The resin composition according to claim 1, wherein the content of the surfactant is 0.1 to 20% by weight of the whole resin composition. 3. The resin composition according to claim 1, wherein the hydrocarbon resin is an ethylene polymer resin. 4. The resin composition according to claim 3, wherein the ethylene polymer resin is an ethylene-α-olefin copolymer having the following properties (a1) and (a2). (A1) Composition distribution variation coefficient (Cx) shown in the following equation 1.
Is 0.5 or less. (A2) The content of the repeating unit derived from ethylene is 80 mol% or more. Cx = σ / SCBave (Equation 1) σ: Standard deviation of composition distribution (1 / 1000C) SCBave: Average value of short-chain branching per 1000C (1 / 1000C) 5. An ethylene polymer resin comprising an ethylene-α-olefin copolymer (A) having the following properties (a1) and (a2) and a low-density polyethylene (B), wherein (A) and (B) ) Is 40:60 to 99: 1.
4. The resin composition according to claim 3, wherein the mixture is: (A1) The composition distribution variation coefficient (Cx) shown in the following equation 1 is 0.5 or less. (A2) The content of the repeating unit derived from ethylene is 80 mol% or more. Cx = σ / SCBave (Equation 1) σ: Standard deviation of composition distribution (1 / 1000C) SCBave: Average value of short-chain branching per 1000C (1 / 1000C) 6. Films comprising the resin composition according to claim 1. 7. The film according to claim 6, wherein the film is for stretch packaging.