JPS6347478Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to a packaging bag or self-supporting container that has excellent mechanical properties, stiffness, transparency, and gloss. polyester film, polyamide film,
Base films such as polypropylene film, which are self-retaining and have excellent mechanical properties, are widely used as packaging films due to their excellent mechanical properties, but it is difficult to thermally bond these films together. It is. Therefore, when used as a packaging bag or self-supporting container, a thermoadhesive film such as unstretched polyethylene or unstretched polypropylene is laminated by extrusion lamination or dry lamination and thermally bonded to form the bag or container. was. However, packaging bags made of such laminated films are still insufficient in terms of strength, elongation, stiffness, etc., and are particularly unsuitable for packaging heavy items. If a thick biaxially oriented film is used as the base film, properties such as strength and stiffness will be improved, but it is technically quite difficult to produce a thick biaxially oriented film, and if the orientation is insufficient, , still strength,
It has disadvantages of poor mechanical properties such as elongation, and poor optical properties such as transparency and gloss. The present invention improves the above-mentioned drawbacks, improves strength,
The present invention provides a packaging bag or a self-supporting container that has improved mechanical properties such as elongation, stiffness, transparency, gloss, and other properties. That is, the present invention comprises a base film made of a uniaxially or biaxially stretched film with a thickness of 10 to 250μ, a polypropylene film layer with a thickness of 10 to 250μ on at least one side, and an at least uniaxially stretched thermal adhesive layer with a thickness of 0.5 to 15μ. This is a packaging bag or a self-supporting container obtained by thermally bonding laminated films laminated in this order. To explain the packaging bag or self-standing container of the present invention with reference to drawings, FIG. 1 is an example of a plan view of the packaging bag of the present invention, and FIG. 2 is an A-A of the packaging bag of FIG. 1. FIG. Figures 1 and 2
In the figure, numerals 1 and 1' are laminated films, and both ends 2 and 2' of the film are thermally bonded to form a bag. FIG. 3 is a cross-sectional view of the laminated films 1 and 1', where 3 is a base film, 4 is a biaxially stretched polypropylene film, and 5 is a cross-sectional view for bonding the base film 3 and the biaxially stretched polypropylene film 4. The adhesive layer 6 is an at least uniaxially stretched thermal adhesive layer. The base film used in the laminated film of the present invention includes stretched films, especially polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyolefins such as polypropylene, nylon 6, nylon 6.6, and polymethaxylene abepate. Uniaxially or biaxially stretched polymer films such as polyamide, polycarbonate, etc. are used. These films have excellent mechanical properties such as strength and elongation, and are characterized by a relatively high melting point. The thickness of the base film is usually 10 to 250μ. The biaxially oriented polypropylene film used for lamination is mainly made of isotactic polypropylene or propylene, with a small amount of ethylene,
A biaxially stretched film of a copolymer of an olefin monomer such as butene-1, a vinyl monomer such as vinyl acetate or styrene, etc. is used, and its thickness is usually 10 to 250 μm. The at least uniaxially stretched thermal adhesive layer laminated to this biaxially stretched polypropylene film includes polyethylene, polybutadiene, ethylene propylene copolymer, ethylene vinyl acetate copolymer,
Polyolefins or olefin copolymers having a low melting point, such as propylene butene copolymers and ethylene butene copolymers, may be used singly or in mixtures, and the thickness thereof is preferably 0.5 to 15 μm. Lamination of a biaxially oriented polypropylene film and at least a uniaxially stretched thermal adhesive layer can be carried out, for example, by laminating the thermal adhesive layer on a polypropylene film stretched in the longitudinal direction and then stretching it in the transverse direction; There are methods such as laminating them by adapter bonding, die bonding, die bonding, etc., or laminating an unstretched polypropylene film and an unstretched heat-adhesive layer film and biaxially stretching them. The base film and the biaxially oriented polypropylene film may be laminated and bonded by thermal bonding using a thermally adhesive resin, but isocyanate-based, cyanoacrylate-based, or epoxy-based resins have good transparency and adhesive strength. It is preferable to laminate and adhere using a strong curable adhesive. For the purposes of the present invention, the total thickness of the base film layer and the biaxially oriented polypropylene layer is preferably at least twice the thickness of the thermocompression bonding layer. The thickness of the laminated film constituting the packaging bag or self-supporting container of the present invention is such that the total thickness of the base film and the biaxially stretched polypropylene film is greater than the thickness of at least the uniaxially stretched thermal adhesive layer. For the purposes of the present invention, the total thickness of the base film layer and the biaxially oriented polypropylene film layer is preferably at least twice the thickness of the thermal adhesive layer. The laminated film used for the packaging bag or self-supporting container of the present invention may be printed, or may be coated with a metal such as aluminum or a metal oxide such as silicon oxide. Although it is necessary that at least one side of the laminated film is a thermal adhesive layer, this thermal adhesive layer may be provided on both sides of the laminated film. Forming packaging bags or self-supporting containers is done using a three-way sealer with a heat seal bar, a vertical pillow bag making machine,
Horizontal pillow bag making machine, bottom film insertion type self-standing container bag making machine, bottom film folding type self-standing container bag making machine, self-standing type that inserts a disc, elliptical plate, or square plate into the bottom of a tube-shaped film and seals the edges. This is done using a container molding machine, etc. The packaging bag or self-supporting container of the present invention is not only strong, sturdy, transparent and glossy, but also has excellent watertightness and gas barrier properties. Therefore, it is used to package heavy foods such as rice, grains, and miso, as well as konjac, pickles, and juices. Of course, it is also used for packaging sweets, ramen, tea, coffee, and frozen foods, and in addition to regular packaging, it can also be used for vacuum packaging, carbon dioxide gas replacement packaging, nitrogen gas replacement packaging, oxygen absorber-containing packaging, etc. For sterilization, boiling treatment, retort treatment, heating treatment in an oven, and heating treatment in a microwave oven can also be performed. Next, an example will be explained with reference to an example. Example Using two extruders, one extruder extrudes polypropylene at 285°C, and the other extruder extrudes ethylene propylene copolymer (ethylene content 4.0 mol%, melting point 145°C) as a thermal adhesive layer. )
was extruded at 250℃, extruded in a multi-manifold die while melting and compounding on one side, cooled with a chill roll at 30℃, then stretched 4.3 times in the longitudinal direction with a stretching roll at 120℃, and then stretched at 140℃ with a tenter.
Stretched 8.0 times in the transverse direction, polypropylene layer 36μ,
A biaxially stretched heat-adhesive polypropylene film having a 4μ ethylene-propylene copolymer layer was obtained. This film was laminated and adhered to base films A, B, and C below using a two-component isocyanate polyester adhesive. A Biaxially oriented polyethylene terephthalate film (thickness 12μ) B Biaxially oriented polypropylene film (thickness
20μ) C Biaxially stretched nylon 6 film (thickness 15μ) The obtained laminated film was thermally bonded to make a packaging bag, and the physical properties were measured. Table 1 shows the results. Comparative Example 1 In the examples, an unstretched polypropylene film (thickness
Table 1 shows the results of making a laminated film using 40μ) and thermally bonding it to make a packaging bag, and measuring various physical properties. Comparative Example 2 An unstretched polyethylene film (thickness: 15 μm) was laminated and bonded to the following base film (thick material) using an isocyanate adhesive and thermally bonded to prepare a packaging bag. D Biaxially oriented polyethylene terephthalate film (thickness 40μ) E Biaxially oriented polypropylene film (thickness
45μ) F Biaxially oriented nylon 6 film (thickness 40μ) The results obtained are shown in Table 1.

[Table] As is clear from comparing the corresponding examples and comparative examples in Table 1, the packaging bag of the present invention is excellent in strength, elongation, haze, tensile modulus, gloss, and elasticity. I know that there is.

[Brief explanation of the drawing]

FIG. 1 is an example of a plan view of the packaging bag of the present invention, and FIG. 2 is a cross-sectional view of the packaging bag of FIG. 1 taken along line A-A. Further, FIG. 3 is a cross-sectional view of a laminated film of the material. 1, 1': laminated film, 2, 2': end portion of laminated film, 3: base film, 4: biaxially oriented polypropylene film, 5: adhesive layer, 6: thermal adhesive layer.

Claims (1)

[Claims for Utility Model Registration] 1. A base film layer consisting of a uniaxially or biaxially stretched film with a thickness of 10 to 250 μm, a biaxially stretched polypropylene film layer with a thickness of 10 to 250 μm on at least one side, and a thermally bonded layer that is at least uniaxially stretched. A packaging bag obtained by thermally bonding a laminated film in which layers are laminated in this order and the total thickness of the base film layer and the biaxially oriented polypropylene film layer is greater than the thickness of the thermally adhesive layer. Freestanding container. 2. The packaging bag or self-supporting container according to claim 1 of the utility model registration claim, wherein the base film is a biaxially stretched polyester film. 3. The packaging bag or self-supporting container according to claim 1 of the utility model registration claim, wherein the base film is a biaxially oriented polypropylene film. 4. The packaging bag or self-supporting container according to claim 1 of the utility model registration claim, wherein the base film is a biaxially stretched polyamide film.