JPH1129667A - Wrap film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a wrap film good in safety, flexibility, sticking property, cutting property, etc., and suitable for heating with an electronic oven, and a cold or a frozen storage by using a resin composition consisting of a polypropylene-based resin and a specific ethylene-α-olefin copolymer. SOLUTION: This wrap film is formed from a resin composition containing (A) 50-98 pt.wt. polypropylene-based resin having preferably 0.5-20 g/10 min (ASTM D1238) and 0.89-0.91 g/cm<3> density and (B) 2-50 pt.wt. ethylene-α-olefin copolymer having <=0.90 g/cm<3> density. By containing 1-50 pt.wt. high pressure polyethylene and 1-30 pt.wt. polybutene based on 100 pts.wt. resin composition, melt physical properties thereof can become easily controllable and adhesion property thereof can be increased further.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wrap film for home use or business use, and more particularly, it has good safety, flexibility, tackiness, cutability, transparency and tear resistance, and can be heated and refrigerated by a microwave oven. The present invention relates to a wrap film suitable for frozen storage.

[0002]

2. Description of the Related Art Conventionally, when food is heated by a microwave oven, or when food is refrigerated,
Polyvinylidene chloride (hereinafter, referred to as "PVD
C), polyvinyl chloride (hereinafter also referred to as “PVC”), polyethylene (hereinafter also referred to as “PE”),
A film containing polypropylene (hereinafter, also referred to as “PP”) as a main component is used.

However, since PVDC and PVC have chlorine in their molecular structure, they cause harmful dioxins by incineration after being discarded, and have a serious environmental problem. . Also, PVC
Has a problem that a whitening phenomenon occurs when it comes into contact with boiling hot water. Further, the PVDC-based wrap film formed from PVDC has a problem that the film shrinks greatly when heated, and the film may be torn due to the shrinkage during heating cooking in a microwave oven, for example. Further, the PVDC-based wrap film is apt to be irregularly torn when cut with a "saw blade" on a box storing the film wound up on a paper tube, and is difficult for a user to use. It has become.

Further, a PE-based wrap film formed of PE has a low glass transition temperature and is suitable for use in storage by freezing or refrigeration. However, since it has a low heat-resistant temperature, it can be heated when used in cooking in a microwave oven. There is a problem that holes are easily opened by the oil component. Also,
A wrap film using an ethylene-vinyl acetate copolymer (hereinafter, also referred to as "EVA") can improve mechanical strength and the like, but has a problem of generating a characteristic acetic acid odor. Further, although the PP-based wrap film formed from PP has high heat resistance, it has low low-temperature embrittlement resistance and is not preferable for frozen storage, and also has low adhesiveness, so that it has an adhesive force to a container, Apply to adhesion. further,
The PP-based wrap film is not easily cut by a “saw blade” because of strong tearing. Further, since each of the conventional wrap films described above contains a large amount of a plasticizer, there is also a problem that the plasticizer precipitates on the film surface during use and contaminates food.

In order to solve the above-mentioned various problems, various proposals have been made on wrap films.
For example, Japanese Patent Publication No. 63-56259 discloses a resin composition in which a polyolefin rubber, polybutene and a tackifier are added to a polypropylene resin. JP-A-6-322194 discloses a styrene-ethylene-butylene-styrene block copolymer (hereinafter referred to as "SEB
S "), polybutene and a tackifier are disclosed. Further, Japanese Unexamined Patent Publication No.
No. 3089 discloses that a polypropylene resin is
A resin composition containing SEBS, EVA saponified product, modified polyolefin-based resin, polybutene and a tackifier is disclosed.

However, as in the resin compositions described in these publications, ethylene-
When a large amount of polyolefin rubber such as propylene rubber (hereinafter also referred to as “EPR”) or a large amount of a styrene elastomer such as SEBS is added, the surface becomes rough due to poor compatibility with polypropylene, and the melt tension is increased. Are insufficient to form a good film, or the obtained film has poor cuttability.

For this reason, a wrap film used for packaging and storing foods or for cooking by heating in a microwave oven or the like has low-temperature embrittlement resistance, high transparency, and is stable to hot water. Therefore, it is required to develop a material that can withstand microwave cooking, has excellent adhesiveness to containers, adhesiveness between films (self-adhesiveness), cutability with a saw blade, and high safety to the environment and the human body. I was

[0008] Accordingly, an object of the present invention is to provide good safety, flexibility, tackiness, cutability, transparency and tear resistance,
An object of the present invention is to provide a wrap film suitable for heating, refrigeration, and frozen storage by a microwave oven.

[0009]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a wrap film formed of a resin composition comprising a combination of a polypropylene resin and a specific resin achieves the above object. I knew that I could get it.

[0010] The present invention has been made based on the above-mentioned findings, and comprises 50 to 98 parts by weight of a polypropylene resin (A) and an ethylene-α-olefin copolymer (B) having a density of 0.90 g / cm ³ or less. A wrap film characterized by being formed from a resin composition comprising 2 to 50 parts by weight.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The wrap film of the present invention is a household or business wrap film (packaging film) used for heating foods in a microwave oven or for refrigeration or freezing of foods. , A polypropylene resin (A) 50 to 98 parts by weight, and a density of 0.90 g / cm
³ or less ethylene-α-olefin copolymer (B) 2
It was formed from a resin composition consisting of 50 parts by weight.

The polypropylene resin as the component (A) used in the resin composition according to the present invention is used as a base material (a resin as a main component) of the resin composition. Examples of the polypropylene resin include, but are not particularly limited to, a propylene homopolymer and a copolymer with an α-olefin other than propylene such as ethylene. Further, the copolymer may be any of a random copolymer and a block copolymer.

It is desirable that the polypropylene resin has a melt index (MI) and a density in a range suitable for ordinary film forming. Specifically, the MI of the polypropylene resin is 0.5 to 20 g / 10 m
in (ASTM D1238),
More preferably, it is 0.5 to 10 g / 10 min. The density of the polypropylene resin is 0.8
It is preferably 9 to 0.91 g / cm ³ . Here, the density of the resin is measured in the same manner as the measurement of the density of a generally known polymer (the same applies to a resin component described below).

The ethylene-α-olefin copolymer having a density of 0.90 g / cm ³ or less, which is the component (B) used in the resin composition according to the present invention, is ethylene and α-olefin other than ethylene. And a copolymer of When the density is 0.90 g / cm ³ or less, the effect of improving the tear of the polypropylene resin as the component (A) and the adhesiveness between films or between a film and a container can be expected. On the other hand, when the density exceeds 0.90 g / cm ³ , there is no problem in the tearing of the polypropylene resin, but the adhesion between the films or between the film and the container is reduced. The density of the ethylene-α-olefin copolymer is preferably 0.90 to 0.86 g /
cm ³ , more preferably 0.88 to 0.86 g /
cm ³ .

By using the ethylene-α-olefin copolymer, the low temperature embrittlement of the polypropylene resin as the component (A) can be improved, and further, the film can be prevented from being torn. The ethylene-α.
By using the olefin copolymer, good adhesion between the films or between the film and the food container can be exhibited.

The ethylene-α-olefin copolymer is not particularly limited as long as the above-mentioned density is satisfied.
An ethylene-α-olefin copolymer obtained by copolymerization using a cyclopentanedienyl complex as a catalyst is preferred.

In the ethylene-α-olefin copolymer, the α-olefin to be copolymerized with ethylene is an α-olefin having 3 to 30 carbon atoms, for example, propylene, 1-butene, 1- Examples include pentene, 1-hexene, 1-octene, 1-heptene, 4-methylpentene-1, 4-methylhexene-1, 4,4-dimethylpentene-1, and octadecene. Among these, 1-hexene, 1-octene, 1-heptene, 4
-Methyl-pentene-1 is preferably used.

In the ethylene-α-olefin copolymer, the cyclopentadienyl complex used as a catalyst when copolymerizing ethylene and α-olefin is a compound represented by the following formula (I): And the like.

ML _X (I) wherein M is a transition metal selected from the group consisting of Zr, Ti, Hf, V, Nb, Ta and Cr, and L is
A ligand coordinated to the transition metal, a group having a cyclopentadienyl skeleton, a hydrocarbon group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, and an aryl group having 1 to 12 carbon atoms.
Roxy group, trialkylsilyl group having 1 to 12 carbon atoms, S
An O ₃ R group (R is a hydrocarbon group having 1 to 8 carbon atoms which may have a substituent such as halogen), a halogen atom or a hydrogen atom, and x is the same number as the valence of the above transition metal It is. However, when a plurality of Ls are coordinated, they may be different groups, but at least one is a group having a cyclopentadienyl skeleton. That is,
When x is 1, the L is a group having a cyclopentadienyl skeleton, and when x is 2 or more, at least one of the plurality of Ls has a cyclopentadienyl skeleton. Is a group having ]

Examples of the group having a cyclopentadienyl skeleton include, for example, cyclopentadienyl group, methylcyclopentadienyl group, dimethylcyclopentadienyl group, trimethylcyclopentadienyl group, and tetramethylcyclopentadienyl group. Enyl group, pentamethylcyclopentadienyl group, ethylcyclopentadienyl group, methylethylcyclopentadienyl group, propylcyclopentadienyl group, methylpropylcyclopentadienyl group,
Alkyl-substituted cyclopentadienyl groups such as butylcyclopentadienyl group, methylbutylcyclopentadienyl group and hexylcyclopentadienyl group; or indenyl group, 4,5,6,7-tetrahydroindenyl group, fluorenyl And the like. Further, these groups may be substituted with a halogen atom, a trialkylsilyl group or the like.

As the above-mentioned group having a cyclopentadienyl skeleton, an alkyl-substituted cyclopentadienyl group is particularly preferable among those exemplified above.

When the compound represented by the general formula (I) contains two or more groups having a cyclopentadienyl skeleton, two of the groups having a cyclopentadienyl skeleton are It may be bonded via an alkylene group such as ethylene or propylene; a substituted alkylene group such as isopropylidene or diphenylmethylene; or a substituted silylene group such as a silylene group or a dimethylsilylene group, a diphenylsilylene group or a methylphenylsilylene group.

The hydrocarbon group having 1 to 12 carbon atoms includes an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group and the like. More specifically, the alkyl group includes a methyl group, Ethyl group, propyl group,
Examples of an isopropyl group and a butyl group include a cycloalkyl group such as a cyclopentyl group and a cyclohexyl group; examples of an aryl group include a phenyl group and a tolyl group; and examples of an aralkyl group include a benzyl group and a neophyl group. And the like. Examples of the alkoxy group include a methoxy group, an ethoxy group, and a butoxy group. Examples of the aryloxy group include a phenoxy group. Examples of the halogen atom include fluorine, chlorine, bromine, and iodine.

Examples of the SO ₃ R group include a p-toluenesulfonato group, a methanesulfonato group and a trifluoromethanesulfonato group.

The compound containing such a group having a cyclopentadienyl skeleton, for example, when the valence of the transition metal is 4, is more specifically represented by the following formula (II).

R ² _k R ³ _l R ⁴ _m R ⁵ _n M (II) wherein M is the above-mentioned transition metal, and R ² is a group having a cyclopentadienyl skeleton (ligand ) And R ³ , R
⁴ and R ⁵ are a group having a cyclopentadienyl skeleton, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, an alkoxy group, an aryloxy group, a trialkylsilyl group, an SO ₃ R group, a halogen atom or a hydrogen atom, respectively. And k is an integer of 1 or more, and k + 1 + m
+ N = 4. ]

In the present invention, in the above formula (II), R
Compounds in which at least two of R ² , R ³ , R ⁴ and R ⁵ , for example, R ² and R ³ are groups (ligands) having a cyclopentadienyl skeleton are preferably used. Groups having a skeleton (eg, R ² and R ³ ) may be linked as described above.

Specific examples of the above compound in which M is zirconium are shown below. Bis (indenyl) zirconium dichloride, bis (indenyl) zirconium dibromide, bis (indenyl) zirconium bis (p-toluenesulfonato) bis 4,5,6,7-
(Tetrahydroindenyl) zirconium dichloride, bis (fluorenyl) zirconium dichloride, ethylenebis (indenyl) zirconium dichloride, ethylenebis (indenyl) zirconium dibromide, ethylenebis (indenyl) dimethylzirconium, ethylenebis (indenyl) diphenylzirconium, ethylenebis ( (Indenyl) methylzirconium monochloride, ethylenebis (indenyl) zirconiumbis (methanesulfonato), ethylenebis (indenyl) zirconiumbis (p-toluenesulfonate), ethylenebis (indenyl) zirconiumbis (trifluoromethanesulfonate), ethylene Bis (4,5,6,7-tetrahydroindenyl) zirconium dichloride, isopropylidene (cyclopentane Enyl - fluorenyl) zirconium dichloride, isopropylidene (cyclopentadienyl - methylcyclopentadienyl) zirconium dichloride, dimethylsilylene bis (cyclopentadienyl)
Zirconium dichloride, dimethylsilylenebis (methylcyclopentadienyl) zirconium dichloride, dimethylsilylenebis (dimethylcyclopentadienyl)
Zirconium dichloride, dimethylsilylenebis (trimethylcyclopentadienyl) zirconium dichloride, dimethylsilylenebis (indenyl) zirconium dichloride, dimethylsilylenebis (indenyl) zirconiumbis (trifluoromethanesulfonato), dimethylsilylenebis (4,5,6,6) 7-tetrahydroindenyl) zirconium dichloride, dimethylsilylenebis (cyclopentadienyl-fluorenyl) zirconium dichloride, diphenylsilylenebis (indenyl)
Zirconium dichloride, methylphenylsilylenebis (indenyl) zirconium dichloride, bis (cyclopentadienyl) zirconium dichloride, bis (cyclopentadienyl) zirconium dibromide, bis (cyclopentadienyl) methylzirconium monochloride, bis (cyclopentane Dienyl) ethyl zirconium monochloride, bis (cyclopentadienyl) cyclohexyl zirconium monochloride, bis (cyclopentadienyl) phenyl zirconium monochloride, bis (cyclopentadienyl) benzyl zirconium monochloride, bis (cyclopentadienyl) ) Zirconium monochloride monohydride, bis (cyclopentadienyl) methylzirconium monohydride, bis (cyclopentadienyl) Methyl zirconium, bis (cyclopentadienyl) diphenyl zirconium, bis (cyclopentadienyl) dibenzyl zirconium, bis (cyclopentadienyl) zirconium methoxychloride, bis (cyclopentadienyl) zirconium ethoxycyclolide, bis (cyclopentane Dienyl) zirconium bis (methanesulfonato), bis (cyclopentadienyl) zirconium bis (p-toluenesulfonato), bis (cyclopentadienyl) zirconium bis (trifluoromethanesulfonato), bis (methylcyclopentadiene) Enyl) zirconium dichloride, bis (dimethylcyclopentadienyl) zirconium dichloride, bis (dimethylcyclopentadienyl) zirconium ethoxycyclolide, bis (dimethylcyclopen Dienyl) zirconium bis (trifluoromethanesulfonato), bis (ethylcyclopentadienyl) zirconium dichloride, bis (methylethylcyclopentadienyl) zirconium dichloride, bis (propylcyclopentadienyl) zirconium dichloride, bis (methylpropylcyclo) (Pentadienyl) zirconium dichloride, bis (butylcyclopentadienyl) zirconium dichloride, bis (methylbutylcyclopentadienyl) zirconium dichloride, bis (methylbutylcyclopentadienyl) zirconium bis (methanesulfonato), bis (trimethyl) Cyclopentadienyl) zirconium dichloride, bis (tetramethylcyclopentadienyl) zirconium dichloride, bis (pentamethylcyclopentadi Enyl) zirconium dichloride, bis (hexylcyclopentadienyl) zirconium dichloride, bis (trimethylsilylcyclopentadienyl)
Zirconium dichloride.

In the compounds exemplified above, disubstituted cyclopentadienyl rings such as dimethylcyclopentadienyl include 1,2- and 1,3-substituted,
Trisubstituted compounds such as dimethylcyclopentadienyl are 1,2,2
Includes 3- and 1,2,4-substitutes. Also propyl,
Alkyl groups such as butyl are n-, i-, sec-, te
It includes isomers such as rt-. Examples of the compound also include a cyclopentadienyl complex in which zirconium is replaced with titanium, hafnium, vanadium, niobium, tantalum, or chromium in the above-mentioned compound in which M is zirconium.

The above cyclopentadienyl complex is
When used, they can be used alone or as a mixture. It may be used after being diluted with a hydrocarbon or a halogenated hydrocarbon. In particular, in the present invention, as the cyclopentadienyl complex, a zirconocene compound in which the central metal atom is zirconium and whose ligand is a group having at least two cyclopentadienyl skeletons is preferably used.

The above cyclopentadienyl complex is
It can be used in combination with an ordinary aluminoxane compound or a compound which reacts with the cyclopentadienyl complex to form a stable anion.

The cyclopentadienyl complex catalyst of the present invention is disclosed in JP-A-4-253711.
JP-A-4-279592, JP-T-6-50358
No. 5, JP-A-3-188092 or JP-A No.
A polymerization catalyst described in JP-A-84407 can also be used.

The mixing ratio of ethylene and α-olefin in the ethylene-α-olefin copolymer is preferably 40 to 98% by weight of ethylene and preferably 60 to 2% by weight of α-olefin.

The above-mentioned ethylene-α-olefin copolymer
Is, for example, ethylene and α-olefin, cyclope
100 to 3,000 kg in the presence of the antadienyl complex
/ Cm ^Two, Preferably 300 to 2,000 kg / c
m^Two, 125-250 ° C, preferably 150-200 ° C
At high temperature by high pressure ion polymerization.
Can be. In particular, the above cyclopentadienyl complex and
To polymerize in combination with the aluminoxane compound,
JP-A-61-130314, JP-A-60-35006
JP, JP-A-58-19309, JP-A-60-3500
No. 8 and JP-A-3-1630088
According to the method, and also the above cyclopentadienyl complex and
A stable anion that reacts with the cyclopentadienyl complex
To polymerize together with compounds that form
Patent No. 277,004, International Publication WO92 / 0
No. 1723, etc.
Can be polymerized.

The molecular weight distribution of the ethylene-α-olefin copolymer is preferably such that the ratio Mw / Mn of the weight average molecular weight to the number average molecular weight measured by GPC is 4 or less, preferably 2 or less. Is more preferred. In addition, an ethylene-α-olefin copolymer MI (ASTM D12
38) is preferably 0.01 to 300 g / 10 mi.
n, more preferably 0.1 to 150 g / 10 min, particularly preferably 0.5 to 30 g / 10 min.

Further, as the above-mentioned ethylene-α-olefin copolymer, a copolymer obtained by copolymerization using a known metallocene catalyst by an ordinary method can also be used.

As described above, the resin composition according to the present invention
50 to 98 parts by weight of component (A) and component 2 of component (B)
When the amount of the component (A) is less than 50 parts by weight (that is, the amount of the component (B) is more than 50 parts by weight), the resin of the component (A) in a matrix state is added to the resin of the component (B). Since the form in which the resin is dispersed is reversed, the heat resistance effect cannot be obtained. On the other hand, when the component (A) is more than 98 parts by weight (that is, the component (B) is less than 2 parts by weight), the effect of modifying the polypropylene resin [component (A)] is small, and tearing occurs. Adhesion between the films or between the film and the container is reduced. In particular, the resin composition according to the present invention, flexibility at low temperature, irregular tear prevention, in terms of further improving the adhesion between the films or between the film and the container,
60-90 parts by weight of component (A) and component 1 of component (B)
Those comprising 0 to 40 parts by weight are preferred.

The resin composition (components (A) and (B)) according to the present invention contains 1 to 50 parts by weight of a high pressure polyethylene (C) based on 100 parts by weight of the composition. The high melt tension characteristic of the high-pressure polyethylene makes it easy to control the melt properties of the entire resin composition. When the content of the high pressure polyethylene is 1
If the amount is less than 10 parts by weight, the effect of increasing the melt tension of the composition may be reduced.If the amount is more than 50 parts by weight, the heat resistance may be reduced because the melting energy is reduced with respect to the composition. There is. Particularly, the high-pressure polyethylene is preferably contained in an amount of 5 to 30 parts by weight based on 100 parts by weight of the composition.

The high-pressure polyethylene is a polyethylene produced by a so-called high-pressure method. For example, low-density polyethylene (hereinafter, also referred to as "LDPE") produced by a high-pressure radical polymerization method can be used.

The resin composition (components (A) and (B)) according to the present invention contains 1 to 30 parts by weight of polybutene (D) based on 100 parts by weight of the composition.
Adhesiveness can be further imparted to the obtained film. When the content of the polybutene is less than 1 part by weight, the adhesive strength that can be imparted to the film is reduced, and the adhesive force between the films or between the film and the container may be reduced. In some cases, the workability at the time becomes difficult, or after the obtained film is wound up, it becomes difficult to unwind it again, or the film adheres slightly wrinkled due to slight adhesion, making it difficult to use. In particular, the polybutene is preferably contained in an amount of 1 to 20 parts by weight based on 100 parts by weight of the composition.

The polybutene preferably has a number average molecular weight of 300 to 3,000 from the viewpoint that the adhesiveness imparted to the film is more easily developed. The number average molecular weight of the polybutene is more preferably from 500 to 2,000, most preferably from 1,000 to 1,500.

Further, the resin composition according to the present invention comprises 1 to 50 parts by weight of the high-pressure process polyethylene [component (C)] and 100 parts by weight of the polybutene [component (D)] based on 100 parts by weight of the composition. Is more preferably contained in an amount of 1 to 30 parts by weight.

The resin composition (components (A) and (B)) according to the present invention contains 1 to 30 parts by weight of fat (E) with respect to 100 parts by weight of the composition. The low-temperature flexibility of the product and the adhesiveness between the films or between the film and the container can be further provided. If the content of the fat or oil is less than 1 part by weight, it may be difficult to obtain the above effects,
If it exceeds 30 parts by weight, the heat resistance may be reduced, or the fat or oil component may bleed out, causing stickiness. In particular, the above fats and oils are 5 to 100 parts by weight of the composition.
It is preferred to contain 20 parts by weight.

As the above fats and oils, hydrocarbon compounds, glycerin ester compounds and sucrose polyesters are preferably used. Among them, glycerin ester compounds and sucrose polyesters are hardly absorbed by the human body and have low accumulation properties. Therefore, it can be particularly preferably used. Examples of the hydrocarbon compound include liquid paraffin. Examples of the glycerin ester compound include ester compounds of glycerin with fatty acids such as stearic acid, oleic acid, lauric acid, caprylic acid, behenic acid, ricinoleic acid, palmitic acid, myristic acid, and capric acid. No. Examples of the sucrose polyester include ester compounds of sucrose with fatty acids such as stearic acid, palmitic acid, myristic acid, oleic acid, lauric acid, behenic acid, and erucic acid.

In the resin composition according to the present invention, 1 to 50 parts by weight of the high-pressure polyethylene [component (C)] and 1 to 50 parts by weight of the above-described oil [(E)] are added to 100 parts by weight of the composition.
Component] is further preferably 1 to 30 parts by weight.

Further, the resin composition according to the present invention includes:
In addition to the above-described components, if necessary, ordinary additives such as antioxidants, colorants, ultraviolet absorbers, inorganic fillers, heat stabilizers, antistatic agents, antifoggants, tackifiers, etc. It can be appropriately contained. The additive is contained in an amount that does not impair the effects of the present invention (preferably 0.01 to 10 parts by weight based on 100 parts by weight of the resin composition).

The resin composition according to the present invention comprises the above components (A) and (B), and optionally (C)
The components (D) and (E) and other additives are added, and the mixture is kneaded sufficiently by a conventional method, for example, dry blending, dry blending, followed by sufficient kneading with a Banbury mixer or an extruder, or kneading, followed by pelletization with a pelletizer or the like. It can be manufactured by a method.

As a method of forming the wrap film of the present invention from the above resin composition, for example, a known inflation method and a T-die method (methods using a film forming apparatus such as an ordinary inflation apparatus and a T-die apparatus, respectively) Etc. can be adopted. In the forming apparatus, the resin composition is heated at a temperature of preferably 180 to 250 ° C., and then extruded and cooled to form a film. In the case of the above-mentioned inflation method, any cooling method of an air cooling type or a water cooling type may be used. In addition, in order to improve the transparency of the obtained wrap film, it is preferable to perform quenching after extrusion. Alternatively, the above resin composition according to the present invention may be used on the surface side to form a multilayer film by coextrusion.

The wrap film of the present invention may be a non-stretched film, but is preferably a stretched film, particularly a biaxially stretched film. By biaxially stretching, the cutting property by the saw blade is improved. In this case, the stretching method is not particularly limited, and the stretching is carried out by a generally known method.
It is preferably in the range of 2 times or more, particularly 2 to 10 times.

The wrap film of the present invention has a thickness of 10 to 20 μm so that it can easily fit into the shape of a container.
m, particularly preferably in the range of 10 to 15 μm.

The wrap film of the present invention obtained as described above has good safety, flexibility, tackiness, cutability, transparency and tear resistance, and is suitable for heating and refrigeration by microwave oven, and frozen storage. It is suitable.

Therefore, the wrap film of the present invention can be suitably used as a household or business wrap film used for heating foods in a microwave oven or for refrigeration or frozen storage of foods.

[0053]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples, but the present invention is not limited to these Examples.

Examples 1 to 7 and Comparative Examples 1 and 2 The respective components shown in Table 1 below were used and kneaded to prepare a resin composition. Next, the resin composition was heated to 230 ° C. using a normal film forming apparatus, and then extruded and cooled to form a film. This was biaxially stretched (stretching ratio: 3.0 times in the longitudinal direction and 3.0 times in the transverse direction) by a usual stretching method to form a wrap film having a thickness of 12 μm.

The obtained wrap film was evaluated for tackiness, cuttability, flexibility and low-temperature flexibility according to the following evaluation criteria. The results are shown in Table 3 below. The details of the components used in each example are shown in [Table 2] below.

Evaluation Criteria [Adhesiveness] A sensory test was carried out when the wrap film was actually adhered to setware, and evaluated according to the following criteria. A: Excellent. ；: Good. Δ: No problem in practical use. X: poor.

[Cutability] The straightness of the tear when the wrap film was cut with a saw blade used for a commercially available wrap film was examined and evaluated according to the following criteria. ○; Δ: Going straight, but sometimes caught on the way. X: It did not go straight and was defective.

[Flexibility] The above wrap film is 10 cm
The evaluation film cut into a size of × 10 cm
Under a condition of 0 ° C., a sensory test was carried out when rolled by hand and evaluated according to the following criteria. A: Excellent. ；: Good. Δ: No problem in practical use. X: poor.

[Low temperature flexibility]
The evaluation film cut into a size of cm × 10 cm was subjected to a sensory test when rolled by hand under a condition of −10 ° C., and evaluated according to the following criteria. A: Excellent. ；: Good. Δ: No problem in practical use. X: poor.

[0060]

[Table 1]

[0061]

[Table 2]

[0062]

[Table 3]

From the results shown in Table 3, the polypropylene resin (component (A)) and the ethylene-α-olefin copolymer having a density of 0.90 g / cm ³ or less [component (B)]
The wrap film of the present invention (Examples 1 to 7) formed from a resin composition having a specific weight ratio is more adhesive, cutable, and flexible than the wrap films of Comparative Examples 1 and 2. It can be seen that the material has excellent low-temperature flexibility.

[0064]

The wrap film of the present invention has good safety, flexibility, adhesiveness, cutability, transparency and tear resistance, and is suitable for heating, refrigeration and freezing storage in a microwave oven.

Claims (6)

[Claims] 1. A polypropylene resin (A) 50 to 98
A wrap film formed from a resin composition comprising 2 to 50 parts by weight of an ethylene-α-olefin copolymer (B) having a density of 0.90 g / cm ³ or less. 2. The wrap film according to claim 1, wherein the resin composition contains 1 to 50 parts by weight of a high-pressure polyethylene (C) based on 100 parts by weight of the composition. 3. The wrap film according to claim 1, wherein the resin composition contains 1 to 30 parts by weight of polybutene (D) based on 100 parts by weight of the composition. 4. The resin composition contains 1 to 50 parts by weight of a high-pressure polyethylene (C) and 1 to 30 parts by weight of a polybutene (D) based on 100 parts by weight of the composition. The wrap film according to 1. 5. The wrap film according to claim 1, wherein the resin composition contains 1 to 30 parts by weight of the fat or oil (E) based on 100 parts by weight of the composition. 6. The resin composition contains 1 to 50 parts by weight of a high-pressure polyethylene (C) and 1 to 30 parts by weight of a fat or oil (E) based on 100 parts by weight of the composition. Item 4. The wrap film according to Item 1.