JPS6364729A - Edge-covered laminate and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain a laminate having a good edge-protection and a good shelf stability, by preparing a laminate whose both surfaces comprise thermoplastic resin layers including at least one or more laser absorbing layer and covering the edge with a thermoplastic resin melted by irradiating a laser ray. CONSTITUTION:A laminate whose both surfaces comprise thermoplastic resin and include at least one or more laser absorbing layer among them is used. Then a laser ray is irradiated from the above edge of the laminate. Each layer 3 and 5 of the laser absorbing layers 3 and 5 at each laminate edge 13, 13 is evaporated and also the thermoplastic resin layers 2, 4 and 6 at each laminate edge 13, 13 are melted by the evaporation heat. A laminate whose edge is covered is obtained by covering each edge face 7 and 7 of the laminate with the melted thermoplastic resin. Polyethylene etc. is used as a resin comprising the thermoplastic resin layers. A layer made of a metal, etc., for instance, is used as the laser absorbing layer. A gas laser etc. for example, whose wavelength is 0.5-4mum is used as the laser ray.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a laminate having end-face coatings and a method for manufacturing the same.

[Conventional technology]

BACKGROUND ART Conventionally, laminates of gas barrier materials such as aluminum foil, paper, thermoplastic resin films, etc. have been used as materials for producing food packaging bags and the like.

It is also known that some of these laminates have their end surfaces coated to prevent water absorption and improve gas barrier properties. As a laminate with edge coatings, (1) A laminate with edge coatings applied by heat sealing a thermoplastic resin.

■ A laminate made by applying edge coating using the hemming method.

The hemming method is a method in which the end face is folded back so that the end face is not exposed to the inside.

■ A laminate made by applying a tape made of a material such as a three-layered stone stack consisting of polyethylene/aluminum/polyethylene to the end face to cover the end face.

■ A laminate made by extruding and coating the edges with molten thermoplastic resin.

etc. are known.

[Problem that the invention seeks to solve]

Conventional laminates without edge coatings have poor storage stability; for example, when stored in a warehouse for a long period of time, moisture in the atmosphere can cause corrosion of the metal from the edges or expansion of the paper, causing the laminate to deteriorate. Significant deterioration.

If the contents are liquid, edge treatment is always necessary.

Furthermore, laminates whose end surfaces are treated by conventional methods have problems in terms of cost, workability, and the like.

For example, in the case of the stacked stone body described in (1) above, since the resin is pressed and welded by a heating means such as a seal bar, the resin adheres to the seal bar etc., resulting in extremely poor workability.
There was a problem that the stability was lacking and the cost was also high.

In addition, in the laminate described in (2) above, since the ends of the laminate are folded back and heat sealed, the folded portion becomes thick and the sealing performance is unstable, and a large amount of the laminate is required to accommodate the folding. The laminate of (2) above requires a special and expensive machine to apply the tape, and the use of the tape incurs additional costs. Furthermore, in the laminate described in (1) above, the extruded film thickness tends to be uneven, and this unevenness often leads to uneven adhesiveness, resulting in weak adhesive strength and poor protection.

The present invention solves the above-mentioned conventional drawbacks, and aims to provide a laminate with good end face protection and good storage stability, and a method for manufacturing the same.

[Means for solving problems]

One of the present inventions is a laminate consisting of a thermoplastic resin layer provided on at least both surfaces and at least one laser light absorbing layer, the end face of which is heated by being melted by irradiation with laser light. The gist of the present invention is a laminate having an edge coating characterized by being coated with a plastic resin, and another aspect of the present invention is a laminate having a thermoplastic resin layer provided on at least both surfaces. A laser beam is irradiated from above the end face of a laminate consisting of a laminate and at least one laser light absorption layer to evaporate the laser light absorption layer at the end of the laminate and melt the thermoplastic resin layer at the end of the laminate. The gist of the present invention is a method for producing a laminate with an edge coating, which is characterized in that the end face of the laminate is coated with a molten thermoplastic resin to obtain a laminate with an edge coating.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an embodiment of the laminate of the present invention.
indicates a laminate. The stacked stone body 1 is composed of a thermoplastic resin layer 2, a laser light absorbing layer 3, a thermoplastic resin layer 4, a laser light absorbing layer 5, and a thermoplastic resin layer 6 laminated in this order from the top surface. has been done.

Further, the end face 7.7 of the laminate 1 is coated with a thermoplastic resin 8.8 which is melted by irradiation with laser light.

In the laminate of the present invention, the resin constituting the thermoplastic resin layer includes polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, ethylene-
Acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-vinyl acetate copolymer, saponified ethylene-vinyl acetate copolymer, ethylene-α-olefin copolymer elastomer, styrene-butadiene-acrylonitrile copolymer , polyamide, polycarbonate, polysulfone, polyacetal, polymethyl methacrylate,
Polyphenylene oxide, polyurethane, polyethylene terephthalate, polybutadiene terephthalate, etc. can be used.

The thickness of the thermoplastic resin layer varies depending on the material, purpose of use of the laminate, etc., but is preferably 5 to 300 μm, preferably 40 to 1 μm.
It is 50 μm.

In addition, in the laminate of the present invention, the laser light absorption layer refers to a layer formed of a material capable of absorbing laser light or a layer containing a material capable of absorbing laser light, for example, a layer formed of metal. (any metal can be used; for example, gold, silver, aluminum, platinum, etc.; the metal layer can be a foil made by rolling, a thin film made by vacuum deposition, or sputtering), formed from paper. or a layer in which metal powder or pigment is dispersed in a molten resin and solidified.

The thickness of the laser light absorption layer varies depending on its material, the purpose of use of the laminate, etc., but is 0.01 to 1000 μm, preferably 0.1 to 20 μm.

In addition, the laser beam used in the present invention includes:
Any conventionally known laser beam can be used, and should be selected appropriately taking into consideration the transparency of the thermoplastic resin and the evaporability of the laser light absorption layer. For example, a gas laser, a solid-state laser, Examples include liquid lasers, semiconductor lasers, Raman lasers, and excimer lasers.

The laminate of the present invention is not limited to the layer structure shown in FIG. 1, but may have a layer structure consisting of a thermoplastic resin layer 9, a laser light absorption layer 10, and a thermoplastic resin N11, for example, as shown in FIG. Alternatively, there may be two or more thermoplastic resin layers in addition to the thermoplastic resin layers on both surfaces, or there may be two or more laser light absorption layers, in short, there may be thermoplastic resin layers on both surfaces. Any layer structure may be used as long as the laminate includes a resin layer and at least one laser light absorption layer.

Furthermore, depending on the intended use of the laminate of the present invention, it is also possible to apply patterns, designs, characters, etc. to the thermoplastic resin layer and/or the laser light absorption layer by printing or the like.

Specific embodiments of the layer configurations shown in FIGS. 1 and 2 above include, for example, those shown below.

■ For the N configuration shown in Figure 1.

i) Polyethylene/low/polyethylene/aluminum/
Polyethylene■ In the case of the layer structure shown in Figure 2.

i) Polyethylene terephthalate/aluminum/polyethylene Ii) Polyethylene terephthalate/low/polyethylene ii) Polyethylene/paper/polyethylene Next, a manufacturing method for manufacturing the above-mentioned laminate will be explained.

As a method for manufacturing the laminate of the present invention, a laminate consisting of a thermoplastic resin layer provided on at least both surfaces and at least one laser light absorption layer is used, and a laser beam is applied from above the end of the laminate. For example, Figure 3 (a)
As shown, a thermoplastic resin layer 2, a laser light absorption layer 3,
Each end 13.1 of a laminate 12 formed by sequentially laminating a thermoplastic resin layer 4, a laser light absorption layer 5, and a thermoplastic resin N6
3. Laser light 14.14 is irradiated from above. Although the irradiation position of the laser beam varies depending on the layer structure, material, etc. of the laminate, it is preferable to irradiate the laser beam at a position approximately 0°1 to 2 u inward from the end face of the laminate. Irradiated laser light 14
．． 14 indicates each thermoplastic resin layer 2 as shown in FIG.
．． 4.6 is transparent. However, it is sufficient that sufficient energy can be transmitted to the absorbing layer without 100% transmission. In the laser light absorption layer 3.5, each laminate end 13.1
At the same time, the thermoplastic resin N2.4.6 at each laminate end 13.13 is melted by the heat of evaporation of the laser light absorption layer. The melted thermoplastic resin is applied to each end surface 7 of the laminate as shown in FIG.
．． 7 is coated to obtain a laminate 1 whose end face is coated.

The laser beam used in the manufacturing method of the present invention has a wavelength of 0.5
It is preferable to use one with a diameter of 4 μm.

Laser light of 0.5 to 4 μm is suitable for passing through the resin layer and evaporating laser light absorbing layers such as paper and aluminum.

Since the manufacturing method of the present invention uses a laser beam, end face processing can be performed in a non-contact manner in which no contact is made with the laminate except for the laser beam, making it extremely easy to work and manufacturing laminates at low cost. It is something that can be done.

Hereinafter, the present invention will be explained in more detail by giving specific examples.

Example 1 Polyethylene film with a thickness of 40 μm, basis weight 200 g
1 from the end surface of the laminate from above the end of the laminate made by laminating /m paper and 40 μm thick polyethylene film.
The inner part of the crane was irradiated with a 100 W type YGA laser beam to evaporate the paper, and each polyethylene film was melted to cover the end face of the laminate. The obtained laminate with end face coating was immersed in water for 3 months to improve delaminability (peelability).
The results of examining the corrosivity of paper, aluminum foil, etc. are shown in Table 1. Example 2 Polyethylene terephthalate film with a thickness of 12 μm,
A laminate with end face coating was obtained in the same manner as in Example 1 using a laminate formed by laminating an aluminum foil with a thickness of 9 μm and a polyethylene film with a thickness of 80 μm. The obtained laminate with end face coating was immersed in water for 3 months, and the delaminability and corrosiveness of paper, aluminum foil, etc. were examined. Table 1 shows the results.

Example 3 Polyethylene film with a thickness of 30 μm, basis weight 150 g
Example 1 using a laminate formed by laminating /rd paper, 30 μm thick polyethylene film, 9 μm thick aluminum foil, and 50 μm thick polyethylene film.
A laminate with end face coating was obtained in the same manner as above. The obtained laminate with end face coating was immersed in water for 3 months, and the delaminability and corrosiveness of paper, aluminum foil, etc. were examined. Table 1 shows the results.

Comparative Example 1 A laminate having the same layer structure as in Example 1 and without end face treatment with laser light was used to examine delamination and corrosion properties in the same manner as in Example 1. The results are also shown in Table 1.

Comparative Example 2 A laminate having the same layer structure as in Example 2 and without end face treatment with laser light was used to examine delamination and corrosion in the same manner as in Example 1. The results are also shown in Table 1.

Comparative Example 3 Using a laminate having the same layer structure as in Example 3 and without end face treatment with laser light, delamination and corrosion properties were examined in the same manner as in Example 1. The results are also shown in Table 1.

Table 1*l The laminates that had been immersed in water for 3 months were taken out and the state of delamination was visually observed.

No peeling...O There is peeling・・・× It was judged as.

*Remove the laminate that has been immersed in water for 23 months and place it on a canter.
Cut the paper, aluminum foil, etc. of the laminate using I! As expected, there is no corrosion of aluminum or expansion of paper.
...O There is some corrosion of the aluminum, or some expansion of the gill.

...△ There is considerable corrosion of aluminum or considerable expansion of paper. ...It was judged as ×.

(Effects of the Invention) As explained above, the laminate of the present invention is a laminate consisting of a thermoplastic resin layer provided on at least both surfaces and at least one laser light absorbing layer, and the end face is exposed to the laser light. Since it is coated with a thermoplastic resin that is melted by irradiation, the end face protection property is extremely good, and the shelf life of the assembled laminate is extremely improved.

Moreover, according to the manufacturing method of the present invention, the above-mentioned good end face protection property,
This has effects such as being able to easily and inexpensively produce a laminate with good storage stability.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention, and FIG. 1 is a longitudinal cross-sectional view showing one embodiment of a laminate to which the end face coating of the present invention has been applied, and FIG. 2 shows another embodiment of the laminate of the present invention. Longitudinal sectional view shown, 3rd
The figure is an explanatory diagram illustrating the method for manufacturing the laminate of the present invention. 1... Laminated body 2 with end face coating applied, 4. 6. 9. 11...Thermoplastic resin 3
．． 5.10... Laser light absorption layer 7... End face of laminate, 14... Laser light @1 Figure 2

Claims (3)

[Claims] (1) A laminate consisting of a thermoplastic resin layer provided on at least both surfaces and at least one laser light absorbing layer, the end surfaces of which are covered with a thermoplastic resin melted by irradiation with laser light. 1. A laminate with an end face coating characterized by: (2) Laser light is irradiated from above the end face of a laminate consisting of a thermoplastic resin layer provided on at least both surfaces and at least one laser light absorption layer, and the laser light absorption layer at the end of the laminate is evaporated. At the same time, the thermoplastic resin layer at the end of the laminate is melted, and the end face of the laminate is covered with the melted thermoplastic resin to obtain a laminate coated with the end face. A method for manufacturing a laminate. (3) A method for manufacturing a laminate coated with an end face according to claim 2, wherein a laser beam having a wavelength of 0.5 μm to 4 μm is used as the laser beam.