JPH0440908Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a packaging material for paper containers that can replace conventional liquid containers such as bottles, cans, and plastics. By coextruding the adhesive and low-density polyethylene into two layers, it increases adhesive strength, improves heat-sealing properties, improves impact strength and gas barrier properties, and eliminates the problem of odor caused by the adhesive between the layers. It has been resolved.

Conventionally, this type of packaging material has been known to have a layered structure of 1 polyethylene, 2 aluminum, 3 polyethylene, 4 paper, and 5 polyethylene, sequentially from the side in contact with the contents, as shown in Figure 1. With this layered structure, when pasting the blanks into a sleeve, this is done by using a gas burner or blowing hot air onto the glue margin to melt the resin on the surface of the blank and crimping it. It is difficult to control the temperature and pressure during crimping, and pinholes are likely to occur due to overheating, and heat seal failures due to insufficient heat are likely to occur.

In addition, in the case of a packaging material with the layered structure shown in Figure 1,
Generally, aluminum 2 and polyethylene 1 are laminated together using an adhesive, which causes an odor from the adhesive, which transfers to the contents such as alcoholic beverages and youth, which poses a quality problem for food packaging. It was hot.

The present invention was conceived in view of the above points, and will be described in detail below based on embodiments shown in the drawings.

First, FIG. 2 is an enlarged cross-sectional view showing the first embodiment, and in order from the side in contact with the contents (lower part of the drawing): low density polyethylene 11 / high density polyethylene 10 / adhesive 9 / aluminum 8 / paper 7/ It has a layered structure of low density polyethylene 6, the innermost layer polyethylene 11 and high density polyethylene 1
0 and is laminated by a coextrusion method. Although omitted in the drawing, the paper 7 and the aluminum 8 are laminated with an adhesive, and
The adhesive 9 between the aluminum 8 and the high density polyethylene 10 can be omitted.

FIG. 3 is an enlarged cross section showing the second embodiment,
In order from the side in contact with the contents (lower part of the drawing), the layer structure is low density polyethylene 11/polypropylene 12/adhesive 9'/aluminum 8/paper 7/low density polyethylene 6. Similarly, the innermost layer of polyethylene 11 and polypropylene 12 are laminated by coextrusion. Note that although it is omitted in the drawing, the paper 7 and aluminum 8 are laminated via an adhesive.
Further, the adhesive 9' between the aluminum 8 and the polypropylene 12 can be omitted.

Note that if a copolymer resin of olefin and unsaturated carboxylic acid or a derivative thereof or a blend thereof is used as the adhesive 9, aluminum 8
It has excellent adhesion strength with other materials and further improves interlayer peel strength.

Since the present invention has the above configuration, it has the following excellent practical effects.

(a) Since the thermoplastic resin layer in contact with the contents has a two-layer structure of high-density polyethylene or polypropylene and low-density polyethylene, it has excellent heat sealing properties, and has high impact strength and barrier properties.

(b) Since the above-mentioned high-density polyethylene or polypropylene and low-density polyethylene are laminated by a co-extrusion method, the adhesive between the aluminum layer and the aluminum layer can be omitted, and unlike conventional adhesives, an unpleasant odor is generated. There is no problem of it transferring to the contents such as alcoholic beverages and youth.

[Brief explanation of the drawing]

Fig. 1 is an enlarged sectional view showing the prior art; Fig. 2;
3 shows an embodiment of the present invention, FIG. 2 is an enlarged sectional view showing the first embodiment, and FIG. 3 is an enlarged sectional view showing the second embodiment. 1,3,5...polyethylene, 4,7...paper,
2,8...aluminum, 6,11...low density polyethylene, 9,9'...adhesive, 10...high density polyethylene, 12...polypropylene.

Claims (1)

[Scope of utility model registration request] A multilayer packaging material containing paper and aluminum and having a thermoplastic resin on the innermost and outermost surfaces, the thermoplastic resin on the innermost surface being laminated with a different polyolefin resin on the aluminum surface by coextrusion. A packaging material for a paper container characterized by the following structure.