JPH04320836A - Packaging material - Google Patents

Abstract

PURPOSE:To eliminate a stripping phenomenon due to dissolution and swelling of adhesives by using a resin which can be directly adhered to a metallic foil, etc., to form layers thereof without providing layers of adhesives. CONSTITUTION:Although any metallic foils having high drawing property can be used, aluminum foils are particularly preferable. From the viewpoint of maintaining of strength, chemical resistance, etc., an aluminum foil 4 is superposed on a 6-60mum polyester or polypropylene film with adhesive 2 or molten polyethylene 3, etc. The thickness of 4-50mum is desirable. A layer of metal adhesive resin 5 having high adhesiveness for aluminum foil is formed over the surface of the aluminum of the layered item 1. Resins to be layered are, for example, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-glycidyl methacrylate copolymer, ethylene-maleic acid copolymer, etc.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to packaging materials, and more particularly to a packaging laminate having excellent resistance to contents (organic solvents).

0002

2. Description of the Related Art Hitherto, extrusion coating or lamination using molten polyethylene has been known as a technique for manufacturing laminated materials for packaging containing metal foil, and dry lamination is also often used. However, in all of these methods, it is essential to use an anchor coating agent or an adhesive at the lamination interface with the metal foil.

0003

[Problems to be Solved by the Invention] In the conventional technology, as mentioned above, an adhesive layer or the like is required at the lamination interface. This adhesive layer generally has the property of dissolving or swelling in organic solvents such as ethyl acetate, toluene, n-hexane, and trichloroethylene. For this reason, if a package laminated in this way is used to package organic solvents or contents containing organic solvents, the organic solvent that has passed through the film layer during long-term storage will cause the above-mentioned damage to the adhesive layer at the laminated interface. There are problems in that the adhesion force is significantly inhibited and a peeling phenomenon occurs. In particular, in gas barrier materials using metal foils such as aluminum foils, organic solvents remain in the adhesive layer on the inner surface of the metal foil, and the above phenomenon becomes more pronounced. Therefore, an object of the present invention is to solve the above problems and provide a packaging material that does not reduce the adhesion of the metal foil surface even when an organic solvent or a material containing the solvent is packaged.

0004

[Means for Solving the Problems] The above objects are achieved by the present invention as described below. That is, the present invention provides a laminated material for packaging containing metal foil, in which a resin layer having adhesive properties with the metal foil is laminated by melting or heat-sealing without providing an adhesive layer at the lamination interface on the inner surface side of the metal foil. In the packaging material and the packaging laminate material including metal foil, the adhesive layer is not provided on the lamination interface on the inner surface side of the metal foil, and other films are bonded to the metal foil through a molten resin having adhesive properties. Or, it is a packaging material characterized by laminating sheets.

[0005]

[Function] As a result of various studies in order to solve the above-mentioned problems, the present inventor has discovered that the adhesive layer can be layered by laminating metal foil or the like directly using a resin that has adhesive properties without providing an adhesive layer. It has been found that the peeling phenomenon caused by dissolution and swelling can be eliminated.

[0006]

[Preferred Embodiments] Next, the present invention will be explained in more detail by citing preferred embodiments. The metal foil used in the present invention is not particularly limited as long as it is a foil of a metal with excellent malleability such as gold, silver, copper, etc., but an industrially particularly suitable metal foil is an aluminum foil. The thickness of these metal foils is generally 4~
Preferably, the thickness is 50 μm. An explanation will be given below using aluminum foil as a representative example. From the viewpoint of strength retention, chemical resistance, etc., the above aluminum foil is coated with any adhesive, anchoring agent, etc.
Used in a laminated state using molten resin such as polyethylene. In this case, the adhesive or anchor agent is on the side that does not come into contact with the organic solvent when the organic solvent is packaged, so special solvent resistance is not required.

[0007] In the first aspect of the present invention, examples of the resin (adhesive resin) having good adhesion to the aluminum foil to be laminated on the aluminum foil surface of the laminate containing the above-mentioned aluminum foil include, for example, ethylene/acrylic resin. Acid copolymer (E
AA), ethylene methacrylic acid copolymer (EMAA)
, ethylene/glycidyl methacrylate copolymer, ethylene/maleic acid copolymer, metal ion crosslinked polymer (ionomer) of ethylene/methacrylic acid copolymer, and the like. These adhesive resins are melted at a temperature above their melting point and subjected to melt extrusion coating, or these resin films or sheets are heat-melted laminated (thermal lamination).
Laminate on aluminum foil by doing. The melting temperature or temperature during heat lamination at this time varies depending on the resin employed, but is generally in the range of 150 to 300°C. The thickness of the melt extrusion coated or hot laminated layer is typically 10
〜50 μm, and the total thickness of the resulting packaging material is 5 to 1 μm.
The thickness is preferably about 50 μm. In a second aspect of the present invention, the adhesive resin described above is melt-extruded and coated on the surface of an aluminum foil, and another resin film or sheet is bonded and laminated using this molten resin as an adhesive layer. As the material to be laminated and laminated, the above-mentioned resin film or a plastic film such as polyethylene or polypropylene film having a thickness of about 20 to 400 μm is used.

[0008]

[Embodiments] Next, the present invention will be explained in more detail with reference to the embodiments shown in the drawings. First, the packaging material of the present invention has a structure as shown in FIGS. 1 to 3. In the figure, 1 is a heat-resistant plastic film such as biaxially stretched polyester film or polypropylene film, and 2 is a general adhesive such as polyester, polyurethane, or polyethyleneimine. 3 is preferably the adhesive resin described above, but it may also be a resin layer of polyethylene, polypropylene, etc., and is laminated by extrusion coating or dry lamination. 4 is aluminum foil. Laminates consisting of these 1 to 4 are commercially available and used in the present invention. Reference numeral 5 in FIG. 1 is the aforementioned melt-extruded resin layer with metal adhesive properties, and reference numeral 6 in FIG. 2 is the above-mentioned plastic film or sheet laminated with metal adhesive resin as an adhesive layer. Reference numeral 7 in FIG. 3 denotes a layer obtained by thermally laminating the metal-adhesive resin described above into a film or sheet onto an aluminum surface.

Example 1 Polyethylene terephthalate (16μ
m) / Anchor layer / Extruded EMAA20 (μm) / Aluminum foil (9 μm) / Extruded EMAA (20 μm) / EM
A packaging material of the present invention having the structure of AA film (40 μm) was prepared. Extruded EMAA: Nuclell 1108C (manufactured by DuPont Mitsui Polychemicals) EMAA film: NC-4 (manufactured by Tamapoli)

0010
] Example 2 Polyethylene terephthalate (12μ
m) / anchor layer / extruded polyethylene (20 μm) / aluminum foil (9 μm) / extruded ionomer (40 μm)
) The packaging material of the present invention was prepared. Extruded ionomer: Himilan #1652 (manufactured by DuPont Mitsui Polychemicals)

Example 3 Polyethylene terephthalate (25μ
m)/Polyester adhesive/Aluminum foil (12μ
A packaging material of the present invention was prepared, having the structure of a /EMAA sheet (heat laminated, 100 μm).

Comparative Example 1 Polyethylene terephthalate (12μ
A packaging material of a comparative example was prepared with the following structure: m)/anchor layer/extruded polyethylene (20 μm)/aluminum foil (9 μm)/anchor layer/extruded polyethylene (20 μm)/polyethylene film (40 μm).

Comparative Example 2 Polyethylene terephthalate (12μ
m)/Polyester adhesive/Aluminum foil (9μm)
/Polyester adhesive/Polypropylene film (60
A packaging material of a comparative example with a structure of .mu.m) was created. Bags were made from the packaging materials of the above Examples and Comparative Examples, and after putting a solvent inside and leaving them at 40°C for 7 days, we examined whether there was any abnormality in the adhesion of the inner aluminum foil surface, and the results are shown in Table 1 below. Obtained.

[0014]

[Table 1]
Example
Comparative example
Contents 1 2
3 1 2
Toluene ○
○ ○ ×
× Ethyl acetate
○ ○ ○ ×
× Methanol
○ ○ ○
△ △ n-hexane ○ ○
○ × ×
Trichlorethylene ○ ○
○ × ×
Dichloromethane ○
○ ○ × ×

[
0015

According to the present invention as described above, a packaging material is provided in which the adhesive strength of the aluminum foil surface does not decrease even when an organic solvent or a material containing the solvent is packaged. The above packaging material of the present invention is impregnated with organic solvents, liquids such as ink, paint, cosmetics, etc. containing organic solvents, which were difficult to package with aluminum foil laminated barrier packaging materials such as aluminum foil. Suitable for packaging plastic products, etc., and enables stable storage for long periods of time.

[0016]

[Brief explanation of drawings]

FIG. 1 is a diagram illustrating a cross section of the packaging material of the present invention.

FIG. 2 is a diagram illustrating a cross section of the packaging material of the present invention.

FIG. 3 is a diagram illustrating a cross section of the packaging material of the present invention.

[Explanation of symbols]

1: Plastic film or sheet 2: Adhesive 3: Resin layer 4: Aluminum foil 5: Metal adhesive resin 6: Plastic film or sheet

Claims (4)

[Claims] [Claim 1] In a packaging laminate containing metal foil,
A packaging material characterized in that a metal foil and an adhesive resin layer are melt laminated or heat-sealed laminated without providing an adhesive layer on the lamination interface on the inner surface side of the metal foil. [Claim 2] In a packaging laminate containing metal foil,
A packaging material characterized in that another film or sheet is laminated via a molten resin having adhesive properties with the metal foil without providing an adhesive layer on the lamination interface on the inner surface side of the metal foil. [Claim 3] The resin adhesive to the metal foil is an ethylene/acrylic acid copolymer, an ethylene/methacrylic acid copolymer, an ethylene/glycidyl methacrylate copolymer,
The packaging material according to claim 1 or 2, which is selected from the group consisting of metal ion crosslinked polymers (ionomers) of ethylene/maleic acid copolymer and ethylene/methacrylic acid copolymer. 4. The packaging material according to claim 1 or 2, wherein the metal foil is aluminum foil.