JPH09187894A - Packaging material - Google Patents

Abstract

(57) [PROBLEMS] To provide a packaging material that is easy to laminate, has no influence on the contents, and has excellent adhesive strength, low-temperature impact resistance, and the like, and is highly stable. SOLUTION: A modified polypropylene membrane obtained by graft-polymerizing a carboxyl group-containing ethylenically unsaturated monomer onto a propylene homopolymer or a copolymer of propylene and an α-olefin polymerized by using a single-site catalyst. It is a packaging material obtained by stacking and aluminum foil.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a packaging material suitable for packaging various foods, daily necessities, cosmetics, pharmaceuticals, chemicals and the like.

[0002]

2. Description of the Related Art Conventionally, various packaging materials have been proposed for packaging various articles, and one of them is a packaging material containing a laminate in which an aluminum foil and a polypropylene film are laminated. Are known. In order to laminate the above aluminum foil and polypropylene film, usually a polyurethane adhesive is used and dry laminating
It is laminated using the method.

[0003]

By the way, when laminated by the above method, it takes 5 to 7 days until the isocyanate compound as the adhesive component chemically reacts with the polyol to exert the adhesive force. There is a problem in that the aging process must be performed. Further, in the above method, there is a problem that the adhesive strength varies and the adhesive strength is lowered depending on the contents to be filled. Therefore, for example, JP-A-54-51690 and JP-A-5-51690
As disclosed in Japanese Patent Publication No. 4-119576, etc., a method of thermally adhering to an aluminum foil using a modified polypropylene obtained by copolymerizing polypropylene and an unsaturated carboxylic acid has been proposed. However, in the method using the modified polypropylene as described above, there is a problem that a low molecular weight substance in the modified polypropylene is bleed and migrates into the contents, and the low temperature drop impact property is extremely poor. There is a problem. Therefore, the present invention is to provide a packaging material which can be easily laminated, has no influence on the contents, and has excellent adhesive strength, low temperature impact resistance and the like, and which is rich in stability.

[0004]

Means for Solving the Problems As a result of various studies to solve the above problems, the present inventor has found that a propylene homopolymer polymerized using a single site catalyst or propylene and an α-olefin are polymerized. Focusing on the copolymer, in order to utilize the properties such as low amount of low molecular weight substances, excellent low-temperature impact resistance, etc., by graft-polymerizing a carboxyl group-containing ethylenically unsaturated monomer When modified polypropylene was manufactured and laminated on aluminum foil to form a packaging material, there was no migration of low molecular weight substances to the contents, high adhesive strength, strong low-temperature impact resistance, and extremely stable The present invention has been completed with the finding that it is possible to produce a packaging material rich in water.

That is, according to the present invention, a propylene homopolymer or a copolymer of propylene and an α-olefin polymerized by using a single site catalyst is graft-polymerized with a carboxyl group-containing ethylenically unsaturated monomer. A packaging material comprising a modified polypropylene film and an aluminum foil laminated together, and further comprising another material laminated on the laminated body.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below. First, for the present invention described above, a propylene homopolymer or a copolymer of propylene and an α-olefin polymerized by using a single site catalyst will be described. A single site catalyst (metallocene catalyst,
The so-called Kaminski-catalyst) has a characteristic that the active sites are uniform (single site), and specifically, it is a catalyst composed of a metallocene-based transition metal compound and an organoaluminum compound. In some cases, it is used by being carried by an inorganic substance.

In the above, the metallocene-based transition metal compound is, for example, a transition metal selected from Group IVB,
For example, titanium (Ti), zirconium (Zr),
Hafnium (Hf) has 1 cyclopentadienyl group, a substituted cyclopentadienyl group, an indenyl group, a substituted indenyl group, a tetrahydroindenyl group, a substituted tetrahydroindenyl group, a fluorenyl group or a substituted fluorenyl group.
Or two or more of these two groups are linked by a covalent bond to form a bond, and further, a hydrogen atom, an oxygen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group. And those having a ligand such as an acetylacetonate group, a carbonyl group, a nitrogen molecule, an oxygen molecule, a Lewis base, a substituent containing a silicon atom, and an unsaturated hydrocarbon.

In the above, examples of the organoaluminum compound include alkylaluminum, chain or cyclic aluminoxane, and the like. Examples of the alkyl aluminum, for example, triethyl aluminum, triisobutyl aluminum, dimethyl aluminum chloride, diethyl aluminum chloride,
Methyl aluminum chloride, ethyl aluminum chloride, dimethyl aluminum fluoride, diisobutyl aluminum hydride, diethyl aluminum hydride, ethyl aluminum sesquichloride and the like can be mentioned. The chain or cyclic aluminoxane is produced by contacting alkylaluminum and water, and for example, alkylaluminum is added at the time of polymerization and water is added later, or a complex salt is formed. It can be obtained by reacting water of crystallization or adsorbed water of an organic / inorganic compound with alkylaluminum.

Next, in the present invention, silica gel, zeolite, diatomaceous earth and the like can be mentioned as the inorganic material for supporting the above single site catalyst.

In the present invention, examples of the polymerization method include bulk polymerization, solution polymerization, suspension polymerization and gas phase polymerization. Thus, in the present invention, the polymerization may be either batch type or continuous type. Further, in the present invention, the polymerization conditions include, for example, a polymerization temperature of usually -100 ° C to 25 ° C.
The polymerization time is usually 5 minutes to 10 ° C.
The reaction pressure is usually from atmospheric pressure to 300.
It is about kg / cm ² .

In the present invention, propylene is used as a monomer for polymerization using a single-site catalyst, and α-olefins to be copolymerized therewith are, for example, 1-butene and 3-methyl-1-. Examples thereof include α-olefins such as butene, 4-methyl-1-pentene, 1-hexene, 1-octene and decene. Thus,
The copolymerization ratio of these α-olefins is 0.5
To about 80 mol% is preferable. In the present invention, by selecting a single-site catalyst, the homopolymer of propylene is syndiotactic polypropylene or isotactic polypropylene, and the syndiotacticity of each is 85% or more. In the present invention, a homopolymer of propylene is most desirable, and its physical properties are, for example, that the molecular weight distribution is Mw / Mn = 1.5.
It is preferable that the density is 0.88 (g / cm ² ) and the melt index [MI] is 1.5 to 20. In the present invention, the propylene homopolymer polymerized using a single site catalyst or the copolymer of propylene and α-olefin includes, for example, an antioxidant, an ultraviolet absorber, an antistatic agent, an antiblocking agent. Additives such as flame retardants, inorganic or organic fillers, colorants such as dyes or pigments, and the like can be optionally added.

Next, in the present invention described above, a propylene homopolymer polymerized using a single site catalyst as described above or a copolymer of propylene and α-olefin is added to a carboxyl group-containing ethylenically unsaturated monomer. Explaining the modified polypropylene obtained by graft-polymerizing the monomer, first, as the carboxyl group-containing ethylenically unsaturated monomer to be graft-polymerized, for example, acrylic acid,
Methacrylic acid, maleic acid, fumaric acid, ethylenically unsaturated carboxylic acids such as itaconic acid, maleic anhydride, ethylenically unsaturated carboxylic acids such as citraconic anhydride,
Methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl hexyl acrylate,
Glycidyl acrylate, ethylenically unsaturated carboxylic acid esters such as glycidyl methacrylate, acrylamide, methacrylamide, maleimide, acrolein, methacrylolein, ethylenically unsaturated carboxylic acid amides such as vinyl methyl ketone, -imide, -Aldehyde ketones etc. can be used.

Further, in the present invention, as a method for producing a modified polypropylene by graft polymerization, for example,
As described above, a propylene homopolymer polymerized using a single site catalyst or a copolymer of propylene and an α-olefin is contacted with a carboxyl group-containing ethylenically unsaturated monomer in the presence of a reaction initiator. The modified polypropylene can be produced by a method such as graft polymerization. More specifically, for example, as an initiator, an organic peroxide-based initiator such as dicumylperoxide, or an azo compound-based initiator such as azobisisobutyronitrile is used, and a reaction is carried out in a solvent system, or It can be carried out by a method such as kneading with an extruder or a kneader to react. In the present invention, γ
It can also be performed by a method of irradiating with a beam, an electron beam or the like. In the present invention, after the reaction, the unreacted monomer, the initiator and the like may be washed and extracted to remove the impurities to produce the modified polypropylene.

Next, in the above-mentioned present invention, a method for producing a packaging material by laminating the modified polypropylene membrane produced as described above on an aluminum foil will be explained. The packaging material according to the present invention can be produced by a method of laminating a material, for example, an extrusion lamination method, a coextrusion lamination method, or the like. In the above, when laminating, it is necessary to melt the modified polypropylene on the surface of the aluminum foil, and it is preferable to heat the aluminum foil at the time of laminating or reheat after laminating. Thus, in the present invention, when performing the above-mentioned lamination, the film can be subjected to a pretreatment such as corona treatment or ozone treatment, if necessary.

In the above-mentioned present invention, as the aluminum foil, for example, an aluminum foil having a thickness of about 5 μm to 30 μm or an aluminum foil having a thickness of 500Å to 2000Å, which is usually used when constructing a packaging material, is used. A resin film provided with a vapor deposition film or the like can be used.

Thus, in the present invention, the packaging material produced as described above may be further selected from other packaging materials such as the packaging purpose, the contents to be packaged, the packaging form, the packaging method, etc. In a usual packaging bag, a base material having rigidity that constitutes an outer layer and having excellent strength or a base material having a barrier property that constitutes an intermediate layer, a base material having a heat seal property that constitutes an inner layer, The packaging material according to the present invention can be manufactured by arbitrarily selecting and stacking other base materials.

In the above-mentioned present invention, a base material having rigidity and excellent strength to be used as an outer layer is a basic material constituting a packaging bag, so that it is mechanical, physical, chemical, etc. In the above, a resin film or sheet having excellent properties can be used. Specifically, for example, polyester resin, polyamide resin, polyaramid resin, polypropylene resin, polycarbonate
It is possible to use a film or sheet of a tough resin such as epoxy resin, polyacetal resin, fluorine resin and the like. Thus, a film or sheet of the above resin
As the film, either an unstretched film or a stretched film uniaxially or biaxially stretched can be used. In the present invention, the thickness of the resin film may be a thickness that can be kept to the minimum necessary for strength, rigidity, etc., and is about 6 μm to 50 μm, preferably about 9 μm to 25 μm.
Rank is the most desirable.

Next, in the present invention, as the base material having a barrier property as the intermediate layer, a material having a property of blocking light such as sunlight or a property of not transmitting water vapor, water, gas, etc. Can be used, and this may be a single base material or a composite base material in which two or more base materials are combined. Specifically, for example, a resin film having an aluminum foil having a light-shielding property and a barrier property or a vapor-deposited film thereof, a silicon oxide film having a barrier property, a resin film having a vapor-deposited film of an inorganic oxide such as aluminum oxide. , Water vapor, water barrier
Low-density polyethylene, medium-density polyethylene,
Films or sheets of high-density polyethylene, linear low-density polyethylene, polypropylene, ethylene-propylene copolymer, etc., polyvinylidene chloride having a gas barrier property, polyvinyl alcohol, ethylene-vinyl acetate copolymer Resin film or sheet such as saponified product
A colorant such as a pigment or the like may be added to the resin, and other desired additives may be added and kneaded to form a film, and various light-shielding colored resin films or sheets may be used. These materials can be used alone or in combination of two or more. The thickness of the above-mentioned film or sheet is arbitrary, but is usually preferably about 5 μm to 300 μm, more preferably about 10 μm to 100 μm. Further, in the above, the aluminum foil has a thickness of about 5 μm to 30 μm,
As a deposited film of aluminum or an inorganic oxide, a film having a thickness of about 100 to 2000 mm can be used. Examples of the resin film supporting the above-mentioned vapor-deposited film include a polyester film, a polyamide film, a polyolefin film, a polyvinyl chloride film, a polycarbonate film, a polyvinylidene chloride film, a polyvinyl alcohol film, and an ethylene-acetic acid film. Saponified vinyl copolymer films and the like can be used. In addition, in the above, since the aluminum foil having the light shielding property and the barrier property or the resin film having the vapor deposition film thereof is used when laminating the film made of the modified polypropylene described above, it is not always necessary to use it in duplicate. There is no.

In the present invention, the heat-sealable base material used as the inner layer may be any material that can be melted by heat and fused to each other, for example, low-density polyethylene, Medium density polyethylene, high density polyethylene, linear low density polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ionomer resin, ethylene-acrylic acid copolymer, ethylene-ethyl acrylate copolymer, ethylene-methacrylic acid copolymer Films or sheets of resins such as polymers, propylene-α-olefin copolymers, methylpentene polymers, polybutene polymers, acid-modified polyolefin resins and the like can be used. The thickness of the film is 1
It is desirably about 0 μm to 300 μm, preferably about 20 μm to 100 μm.

Next, in the present invention, in addition to the above-mentioned materials, for example, other materials satisfying properties such as chemical resistance, solvent resistance, hygiene resistance, etc. may be optionally used. Can, specifically, a film of the resin listed above,
Alternatively, a resin film other than that, a film such as cellophane, a paper base such as synthetic paper, thin paper, paperboard, and processed paper, and the like can be used.

In the present invention described above, a method of laminating using the above materials will be explained. As such a method, as described above, a method of laminating a normal packaging material, for example, Wet lamination method, dry lamination method, solventless dry lamination
Method, extrusion lamination method, T-die coextrusion molding method, coextrusion lamination method, and the like. Thus, in the present invention, when performing the above-mentioned lamination, the film can be subjected to a pretreatment such as corona treatment or ozone treatment, if necessary.
For example, an isocyanate-based (urethane-based), polyethyleneimine-based, polybutadiene-based, organic titanium-based anchor coating agent, or a polyurethane-based, polyacrylic-based, polyester-based, epoxy-based, polyvinyl acetate-based, cellulose Known anchor coating agents, adhesives and the like such as adhesives for laminating such as base type and others can be used.

Next, the layer structure of the packaging material according to the present invention will be specifically described with reference to the drawings with reference to FIGS. 1 to 5. It is sectional drawing which shows the layer structure of a material. As shown in FIG. 1, the packaging material A according to the present invention comprises a propylene homopolymer polymerized using a single-site catalyst or a copolymer of propylene and α-olefin, and a carboxyl group-containing ethylenic unsaturated compound. It has a structure in which a film 1 made of modified polypropylene obtained by graft-polymerizing a monomer and an aluminum foil 2 are laminated. Further, the packaging material B according to the present invention is, as shown in FIG. 2, a propylene homopolymer or a copolymer of propylene and an α-olefin polymerized by using a single site catalyst as described above. , A film made of modified polypropylene obtained by graft-polymerizing a carboxyl group-containing ethylenically unsaturated monomer 1
And a aluminum foil 2 are laminated on the packaging material A, and one or more layers 3 of other materials are optionally laminated on one or both sides of the packaging material A. It is a thing.

As a specific example of the packaging material B according to the present invention described above, as shown in FIG. 3, a propylene homopolymer polymerized by using a single-site catalyst or a copolymer of propylene and α-olefin is used. A film 1 made of modified polypropylene obtained by graft polymerization of a carboxyl group-containing ethylenically unsaturated monomer and an aluminum foil 2 are laminated on the united body, and the outer layer is formed on the surface of the aluminum foil 2 in a usual packaging bag. A package having a structure in which a base material 4 having a high rigidity and a high strength is laminated, while a base material 5 having a heat seal property forming an inner layer is laminated on the surface of the modified polypropylene film 1. It is related to the material C. In the packaging material C as described above, the two sheets of the packaging material C are made to face each other with the surfaces of the base material 5 having the heat-sealing property constituting the inner layer opposed to each other and the peripheral end portion of the outer periphery thereof is heat-sealed. It is suitable for producing a soft packaging bag, and mainly for producing a plastic soft packaging bag or the like for filling and packaging confectionery, beverage, drug solution, etc.

Further, the packaging material B according to the present invention described above.
As another specific example, as shown in FIG. 4, a propylene homopolymer polymerized using a single-site catalyst or a copolymer of propylene and α-olefin is added to a carboxyl group-containing ethylenic unsaturation. A film 1 made of modified polypropylene obtained by graft-polymerizing a monomer and an aluminum foil 2 are laminated, and the surface of the aluminum foil 2 has rigidity enough to form an outer layer in a usual packaging bag in the same manner as above. The base material 4 having excellent strength is laminated, on the other hand, the surface of the membrane 1 made of the modified polypropylene is laminated with the base material 5 having a heat seal property which constitutes an inner layer, and the rigidity which constitutes the outer layer described above. And a base material 6 having a barrier property that constitutes an intermediate layer on the surface of the base material 4 having excellent strength, and a heat seal property that constitutes an outer layer on the surface of the base material 6. Laminated substrate 5 ' Those relating to packaging materials D consisting of adult. Thus, the packaging material D as described above is
It is rounded and the polymerized end is heat-sealed to produce a tubular body, which is injection-molded or compression-molded using polypropylene that constitutes the shoulder, mouth, etc. of the head of the tubular body. It is suitable for producing a tube container, and mainly for producing a tube container for filling and packaging toothpaste, chemicals, etc.

Further, the packaging material B according to the present invention described above.
As for another specific example, as shown in FIG. 5, a propylene homopolymer polymerized using a single-site catalyst or a copolymer of propylene and α-olefin is added to a carboxyl group-containing ethylene group. A film 1 made of modified polypropylene obtained by graft polymerization of an unsaturated monomer and an aluminum foil 2 are laminated, and a paper layer 8 is formed on the surface of the aluminum foil 2 with an adhesive layer 7 interposed therebetween in the same manner as above. On the other hand, on the other hand, the surface of the membrane 1 made of modified polypropylene is laminated with the base material 5 having a heat seal property constituting the inner layer, and further, on the surface of the paper 8 mentioned above, the heat seal constituting the outer layer. The present invention relates to a packaging material E having a structure in which a base material 5'having flexibility is laminated. Then, the packaging material E as described above is used to produce a carton blang plate,
It is suitable for producing liquid paper containers by assembling them, and mainly for producing liquid paper containers for filling and packaging liquid drinks such as juice and liquor, liquid medicines, chemical products, etc. .

[0026]

The above examples are only a few examples of the embodiment of the present invention, and the present invention is not limited thereto. Next, the present invention will be described in more detail with reference to specific examples.

Embodiment 1 (1). Syndiotactic polypropylene polymerized with metallocene catalyst (Syndiotactic degree 92%, MFI
= 3.0) 100 parts by weight were mixed with 0.2 part by weight of maleic anhydride and 0.1 part by weight of dicumylperoxide and kneaded at a temperature of 200 ° C. with a twin-screw extruder to form pellets. (2). Isotactic polypropylene polymerized with metallocene catalyst (isotactic degree 97%, MFI =
4.0) 0.3 parts by weight of maleic anhydride to 100 parts by weight,
0.1 part by weight of dicumylper oxide was mixed and kneaded with a twin-screw extruder at a temperature of 200 ° C. to form pellets. Next, a biaxially stretched polyethylene terephthalate film having a thickness of 12 μm and an aluminum foil having a thickness of 9 μm are bonded together using a two-component mixed urethane adhesive, and then the aluminum foil surface bonded above. Using the modified polypropylene pellets produced in (1) and (2) above, this is extruded to a thickness of 20 μm to form a film of the modified polypropylene and a film of the modified polypropylene. A 50 μm-thick film made of a propylene-ethylene block copolymer was subjected to sand lamination on the surface. On the other hand, the other surface of the above biaxially stretched polyethylene terephthalate film was heated by a heat roll at 180 ° C., and the modified polypropylene produced above was melt-cast into a film to produce a packaging material.

[0027]

Comparative Example 1 (3). Biaxial extrusion was performed by mixing 0.3 part by weight of maleic anhydride and 0.1 part by weight of dicumylperoxide with 100 parts by weight of atactic polypropylene (MFI = 3.5) polymerized using a conventional Tigra-based solid catalyst. The mixture was kneaded with a machine at a temperature of 200 ° C. to form pellets. Next, a biaxially stretched polyethylene terephthalate film having a thickness of 12 μm and an aluminum foil having a thickness of 9 μm are bonded together using a two-component mixed urethane adhesive, and then the aluminum foil surface bonded above. , Above (3)
Using modified polypropylene pellets manufactured in
This was extruded to a thickness of 20 μm to form a film made of the modified polypropylene, and a film made of a propylene-ethylene block copolymer having a thickness of 50 μm was subjected to sand lamination on the film surface made of the modified polypropylene. On the other hand, the other surface of the above biaxially stretched polyethylene terephthalate film was heated by a heat roll at 180 ° C., and the modified polypropylene produced above was melt-cast into a film to produce a packaging material.

[0028]

[Experimental Example] With respect to the packaging materials according to Example 1 and Comparative Example 1 produced above, the adhesive force with the aluminum foil, the extraction amount, etc. were measured. The adhesive strength is measured by peeling a T-shape with a width of 15 mm by a tensile tester at a speed of 50 mm / min, and the extraction amount is 120 mm × 170.
mm square four-way seal pouches were prepared, filled with 200 ml of pure water, subjected to retort treatment at 135 ° C. for 60 minutes, and the chloroform-soluble component of the evaporation residue in water was measured. The results of the above experiment are shown in Table 1 below.

[0029]

[Table 1]

As is clear from the above-mentioned experimental results, the packaging material according to Example 1 has excellent adhesive strength and less migration of the low molecular weight component derived from the adhesive polypropylene due to the retort treatment to the contents. On the other hand, the packaging material according to Comparative Example 1 uses a conventional polypropylene-based adhesive polypropylene, and has many low-molecular weight components derived therefrom.

[0031]

As is apparent from the above description, the present invention focuses on a propylene homopolymer or a copolymer of propylene and α-olefin polymerized by using a single site catalyst, and has a low molecular weight. That there are few things,
In order to utilize the characteristics such as being excellent in low-temperature impact resistance, a modified polypropylene is produced by graft-polymerizing a carboxyl group-containing ethylenically unsaturated monomer into this, and this is laminated on an aluminum foil. When the packaging material is constructed by stacking other materials, there is no migration of low molecular weight substances to the contents, high adhesive strength, strong low temperature impact resistance, and extremely stable packaging material production. It can be done.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a layer structure of a packaging material according to the present invention.

FIG. 2 is a cross-sectional view showing a layer structure of a packaging material according to the present invention.

FIG. 3 is a cross-sectional view showing a layer structure of a packaging material according to the present invention.

FIG. 4 is a cross-sectional view showing a layer structure of a packaging material according to the present invention.

FIG. 5 is a cross-sectional view showing a layer structure of a packaging material according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Membrane made of modified polypropylene 2 Aluminum foil 3 Layer made of other material 4 Substrate having rigidity and excellent strength 5 Substrate having heat sealability 5'Substrate having heat sealability 6 Base material having barrier properties 7 Adhesive layer 8 Paper layer A, B, C, D, E Packaging material

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location B65D 30/02 B65D 30/02

Claims (7)

[Claims] 1. A modified polypropylene obtained by graft-polymerizing a carboxyl group-containing ethylenically unsaturated monomer onto a propylene homopolymer or a copolymer of propylene and an α-olefin polymerized by using a single-site catalyst. A packaging material comprising a film and an aluminum foil laminated together. 2. A modified polypropylene obtained by graft-polymerizing a carboxyl group-containing ethylenically unsaturated monomer onto a propylene homopolymer polymerized using a single-site catalyst or a copolymer of propylene and α-olefin. A packaging material comprising a film and an aluminum foil laminated together and further laminated with another material. 3. The propylene homopolymer is syndiotactic polypropylene or isotactic polypropylene, as defined in claim 1 or 2 above.
The packaging material described in. 4. The packaging material according to claim 1, 2 or 3, wherein the α-olefin is hexene-1, octene-1, or 4-methylpentene-1. . 5. The above-mentioned 1, 2, 3 or 4 wherein the carboxyl group-containing ethylenically unsaturated monomer is an ethylenically unsaturated carboxylic acid or an ethylenically unsaturated carboxylic acid anhydride. The packaging material to be described. 6. A graft polymerization of a carboxyl group-containing ethylenically unsaturated monomer onto a propylene homopolymer or a copolymer of propylene and α-olefin polymerized by using a single site catalyst on the surface of an aluminum foil. Extruded modified polypropylene obtained by lamination,
7. The packaging material according to claim 1, 2, 3, 4 or 5, wherein the extruded laminated modified polypropylene film is remelted and then cooled. 7. Biaxially stretched polyester film layer / adhesive layer / aluminum foil / modified polypropylene film layer / polypropylene film layer, or biaxially stretched polyester film layer / adhesive layer / biaxial stretching from the outside to the inside. A laminated body composed of a nylon film layer / aluminum foil / modified polypropylene film layer / polypropylene film layer, wherein the modified polypropylene film layer is a propylene homopolymer polymerized using a single-site catalyst or propylene and α- A retort packaging material comprising a film made of modified polypropylene obtained by graft-polymerizing a carboxyl group-containing ethylenically unsaturated monomer onto a copolymer with an olefin.