JPS58193256A - Square-bottom bag - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a square bottom bag, and more particularly to a square bottom bag that is inexpensive and has excellent productivity.

2. Description of the Related Art In department stores, supermarkets, and the like, square bottom bags that are self-supporting are used as bags for storing purchased products. Such square-bottomed bags have generally been made of paper, but since they are not satisfactory in terms of water resistance, bags made of plastic film have been developed in recent years.

When making square-bottom bags made of plastic film, the bottom is formed by bending the ends of the cylindrical film, but in order to obtain a durable square-bottom bag, sealing this bottom is the most important. is important.

Therefore, various methods have been proposed for sealing the bottom. Examples include (1) a method of heat welding, (2) a method of bonding with an adhesive, and (3) a method of using an adhesive piece.

However, in the thermal welding method (1), when the bottom is heat-sealed or welded, the cylindrical part of the bag that is in contact with the bottom is welded at the same time, resulting in a high incidence of defective products. In addition, the method (2) of bonding with an adhesive has the disadvantage that the process is complicated. Therefore, method (3) of bonding the adhesive strip with adhesive is most commonly adopted. However, since the pasting strips have traditionally been made of resin films, it is necessary to use expensive thermosetting or catalyst-curing adhesives such as epoxy, urethane, or acrylic adhesives, as well as requiring a curing reaction process. There were drawbacks such as the need for

The object of the present invention is to provide an inexpensive square-bottomed bag that eliminates these drawbacks and has excellent productivity.

That is, the present invention provides a square bottom bag made by bonding an adhesive piece made of a porous material to the outer surface of the bottom formed by bending the end of a cylindrical body made of a thermoplastic resin film. It is.

Here, there is no particular restriction on the thermoplastic resin, and examples thereof include polyethylene, polypropylene, nylon polyester, polyvinyl chloride, polystyrene, etc.The thermoplastic resin includes these thermoplastic resins. It may be a single-fit resin film, a multilayer film, or a laminated film with paper.The adhesive surface of the thermoplastic resin film is preferably subjected to corona discharge treatment, if necessary.

The above-mentioned thermoplastic resin film is made into a cylindrical film, and the cylindrical body is formed by folding the aluminum into a flat film and bonding it. Then, by bending one end of the molded cylindrical body, the bottom of the square bottom bag is formed.

When the square bottom bag of the present invention is prepared, an adhesive piece made of a porous material is adhered to the outer surface of the bottom of the square bottom bag thus formed.

There are a variety of porous materials, including paper, nonwoven fabric, woven fabric, open cell foam film or sheet, and the like. The size of the adhesive piece made of such a porous material is not particularly limited and may be appropriately selected depending on the size of the square bottom bag and the purpose of use.

Although there are no particular restrictions on the adhesive, emulsion-type or solution-type adhesives are preferably used.

Specifically, emulsion adhesives such as vinyl acetate, acrylic, chloroprene, and ethylene-vinyl acetate, aqueous adhesives such as polyvinyl alcohol, and solution adhesives such as vinyl acetate and taloloprene rubber are inexpensive. Therefore, it is preferable.

There are no particular restrictions on the shape of the bottom of the square bottom bag; it may be square,
Various shapes such as triangular shapes can be mentioned, and the shape can be selected as appropriate depending on the purpose of use.

There is no particular restriction on the shape of the sticking piece adhered to the outer surface of the bottom of the square-bottomed bag, and it may not only have the same shape as the bottom of the square-bottomed bag but may also have a different shape.

The adhesive strip may be bonded by applying the above-mentioned adhesive to the bottom row surface of the square bottom bag, the adhesive strip, or both. By gluing a sticker to the outer surface of the bottom of the square-bottomed bag, the bottom of the square-bottomed bag can be sealed.

As described above, since the square bottom bag of the present invention obtained in l ~ uses a porous material for the pasting piece, it is not limited to the type of adhesive, and expensive thermosetting adhesives, catalytic curing adhesives, etc. can be used. This is not necessary, and an inexpensive emulsion-type or solution-type adhesive can be used. Moreover, it is sufficient to simply apply such an adhesive, and there is no need to perform a curing reaction step, so that the manufacturing process of the square bottom bag can be simplified.

Therefore, according to the present invention, a square bottom bag can be manufactured at low cost and with excellent productivity.

Therefore, the square bottom bag of the present invention can be effectively used in the field of packaging various articles.

The following is an example of the present invention.

Example: One end of each cylindrical body of a high-density polyethylene film whose adhesive surface had been subjected to corona discharge treatment (40d, inθ/crn) and a high-density polyethylene film whose outer layer was a foamed layer and whose inner layer was an unfoamed layer was bent and prepared as follows. A patch made of unbleached and bleached kraft paper was adhered using the adhesive shown in Figure 3, to obtain a square bottom bag to which the patch was firmly adhered. It should be noted that when the adhesive piece made of the above polyethylene film was used, no adhesion could be achieved at all.

Adhesive A Ethylene-vinyl acetate copolymer resin adhesive (solid content 55%, viscosity 1800 centivoise/30°C,
pH 4,5) Adhesive B Vinyl acetate adhesive (solid content 50%).

Viscosity 1000 centivoise 150℃, pH 6)

[Brief explanation of drawings]

FIG. 1 is a plan view of the square bottom bag of the present invention, and FIG. 2 is a side view thereof. 1.-. Square bottom packaging body, 2.. Bottom surface of square bottom bag. 5.Patent patch patent applicant Idemitsu Petrochemical Co., Ltd. Agent Patent attorney Kubo 1■ Fujibe 7-

Claims (2)

[Claims] (1) A square bottom bag made by adhering an adhesive piece made of a porous material to the outer surface of the bottom formed by bending the end of a cylindrical body made of thermoplastic resin film. (2) The square bottom bag according to claim 1, wherein the adhesive is an emulsion type adhesive or a solution type adhesive.