JPH0880992A - Flexible container bag - Google Patents

Abstract

PURPOSE: To improve bonding strength between a bag body cloth and a lining cloth provided inside a bag body in a flexible container bag of cubical shape or quadratic prism-like shape comprising a laminated sheet prepared by superposing a thermoplastic resin film on either side of a stretched fabric comprising thermoplastic resin. CONSTITUTION: In a flexible container bag having a lining cloth 2 in a bag body to maintain the configuration of the bag, a bag body cloth 1 and the lining cloth 2 are welded together, and the boundary line at the end of a welded part 3 of the cloth 1 and the cloth 2, where separating stresses are generated, is sewn through a shielding sheet 6 using a sewing machine, and gap-filling waterproof over tapes 5, 8 are welded onto the sewn part from the side the cloth 1 and the cloth 2, respectively, to form a bonded structure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cubic or rectangular parallelepiped flexible container bag composed of a laminated sheet in which a thermoplastic resin film is laminated on both sides of a stretched woven fabric made of a thermoplastic resin. The present invention relates to a flexible container bag having improved joint strength between a bag body cloth and a lining cloth provided inside the bag body.

[0002]

2. Description of the Related Art In a flexible container bag composed of a laminated sheet in which thermoplastic resin films are laminated on both sides of a stretched woven fabric made of a thermoplastic resin, a lining cloth provided inside and a bag body. Joining with cloth is a very important issue for the flexible container bag. That is, a flexible container bag used as a powdery or granular transport bag for foods, grains, fertilizers, chemicals, or synthetic resins has a thermoplastic resin film on both sides of a stretched woven fabric made of a thermoplastic resin. The bag is made up of laminated sheets, and the inner side corners of the side wall of the bag body are welded with a lining cloth for retaining the shape in order to retain the shape, and a hanging belt is provided on the side wall. Has been.

By the way, as a laminated sheet constituting this flexible container bag, an ethylene vinyl acetate copolymer (EVA tarpaulin) and polychlorinated material are provided on both sides of a woven fabric made of a multifilament yarn such as nylon or polyester. Heat-adhesive resin layer such as vinyl (PVC tarpaulin) or high-density polyethylene flat layer
Woven fabric made of polyethylene is used with a polyethylene (PE cloth sheet) thermoplastic resin layer formed on both sides, and this laminated sheet constitutes not only the body cloth of the container bag but also the liner cloth. ing.

Conventionally, as shown in FIG. 3, when joining the bag body and the lining cloth, the both are directly welded. As a welding means, a laminated sheet is PVC tarpaulin or EVA.
A high frequency welder is used in the case of a tarpaulin, and hot air welding is used in the case of a PE cloth sheet. That is, FIG.
1 is a plan view of a joint portion between a bag body cloth and a lining cloth of a conventional flexible container bag, in which a lining cloth 2 is directly welded to a body cloth 1. 3 indicates a welded portion.

However, in the conventional bag body, the flexible container bag obtained by directly welding the bag body and the lining cloth, etc. as shown in FIG. 3 causes peeling stress at the welded portion when high temperature filling or stacking is performed. If it acts on the edges and the adhesive strength between the stretched woven fabric of the laminated sheet and the surface layer film, and the strength and welding strength of the surface layer film are insufficient, peeling troubles occur. When the main body cloth and the lining cloth are peeled off, the original rectangular shape of the bags is lost, and there is a risk of collapse when stacked and stored.

[0006]

Therefore, the inventor of the present invention
The present invention has been completed as a result of various studies to improve the above-mentioned drawbacks, and an object of the present invention is to provide a flexible container bag having an improved joint peel strength between a bag body cloth and its lining cloth.

[0007]

SUMMARY OF THE INVENTION The gist of the present invention is a flexible container bag having a lining cloth for retaining its shape inside a bag body, wherein the body cloth and the lining cloth are welded together, and the body cloth is also welded. A sewing machine is sewn on the boundary line of the side where the peeling stress of the welded portion of the lining cloth and the lining cloth acts, and the waterproof portion of the sewing machine sewn on both the main body cloth surface and the lining cloth surface is sealed. -It is a flexible container bag characterized by welding a burp.

That is, in the present invention, the peeling strength is improved by welding between the main body cloth and the lining cloth to be welded, and sewing on the end boundary line of the welded portion on the side where the peeling stress acts on the sewing machine. In addition, in order to prevent the lint from mixing into the filling in the bag from the sewing part of the sewing machine, and to prevent the infiltration of water from the outside through the sewing part of the sewing machine, the main body cloth surface and the lining cloth surface The waterproof waterproof tape is welded from both sides.

The present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a joint portion where a bag body cloth and a liner cloth of a flexible container bag of the present invention are joined, FIG. 2 is a sectional view of another embodiment, and FIG. 3 is a cross section of a conventional joint portion. It is a figure. As shown in FIG. 3, conventionally, the main body cloth 1 and the lining cloth 2 are simply welded together. On the other hand, in FIG. 1 which is the joining portion of the present invention, the lining cloth 2 is welded on the main body cloth 1, and the sewing sewing 7 is performed on the end portion 4 of the welded portion 3 where the peeling stress acts. . And, on the place where the sewing 7 is performed, a waterproof waterproof seal is applied from both the lining surface and the main body surface.
The bar tape 5 is welded. FIG. 2 is a cross-sectional view of another embodiment of the joint portion where the bag body cloth and the lining cloth of the flexible container bag of the present invention are joined, and the welding portion between the body cloth 1 and the lining cloth 2 is shown. 3 is a cross-sectional view of a case where sewing is performed by interposing a shielding sheet 6 on the end portion 4 of FIG. By inserting the shielding sheet into the sewing position of the sewing machine, the contents inside the bag are prevented from coming into contact with the sewing thread of the sewing machine to generate lint and the like to cause foreign matter to be mixed.

In the present invention, the laminated sheet which can be used as the main body cloth and the liner cloth includes high density polyethylene (HDPE) and other thermoplastic resins such as linear low density polyethylene (LLDPE) and ethylene vinyl acetate. Polymer (EV
A), a flat yarn laminated or blended with polypropylene or the like, or a low density polyethylene (LDPE), a linear low density polyethylene (L) on both sides of a woven fabric made of a multifilament yarn such as nylon or polyester.
LDPE), ethylene vinyl acetate copolymer (EVA),
A heat-adhesive resin layer such as polyvinyl chloride is formed. Further, as the sealing waterproof over tape, the same one as the main body cloth is preferable for the main body cloth surface, and a film which can be heat-welded with the lining cloth for the lining cloth surface, Sheets or laminates are preferred. As the shielding sheet, a synthetic resin film, a sheet or a laminated product thereof is preferable. As a welding means for the main body cloth and the lining cloth, conventionally used, for example, heat adhesion by a bar, heat adhesion by hot air, or in the case of a tarpaulin using vinyl chloride as the surface resin, A bonding method such as a high frequency welder can be used. As the sewing machine for sewing, a device such as a general industrial sewing machine is used, and the sewing thread used for this is polyester thread, nylon thread, polypropylene thread, polyethylene thread or the like. Next, the present invention will be specifically described with reference to examples.

[0011]

【Example】

Example 1 A flexible container bag having a polyethylene cloth sheet obtained by laminating a LLDPE film having a thickness of 60 .mu. On both sides of a polyethylene cloth woven with 2000 denier high-density polyethylene flat yarn having a warp and weft of 15 threads / inch each. The body cloth of Thickness 5 as lining cloth
A 2000-denier high-density polyethylene flat yarn is laminated on both sides of a 0-μ LLDPE film with a plain weave polyethylene cloth having a warp and weft length of 15 threads / inch, and a thickness of 60 μ LL
A sheet on which DPE films were laminated was used. When joining the main body cloth and the lining cloth, first, the main body cloth and the lining cloth are welded with hot air, and then the end portion where the peeling stress acts is made of polyester #
Sewing was performed using a 4 / # 4 thread. Then, the sewing-sewn portion was welded to a lining cloth surface with a sealing waterproof over tape in which a linear low-density polyethylene film (LLDPE) was laminated on both sides of a polyester film having a width of 20 mm. The same sheet as the main body cloth was heat-welded to the main body cloth surface. The peel strength of the obtained joint was measured, and the results are shown in Table 1. As a comparative example, Table 1 shows the peel strength of the joint portion obtained by only the conventional welding. The main body cloth used at this time was the same as in Example 1, and the lining cloth was also the same as in Example 1.

[0012]

[Table 1]

[0013]

As described above, according to the present invention, the main body cloth and the lining cloth are welded together, and the peeling stress action side end portion of the welded portion is sewn with the sewing machine, so that the peeling strength is significantly improved. As a result, the rectangular shape of the flexible container bag can be maintained even by high-temperature filling, and thus stacking strength and storage efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an embodiment of a joint portion between a main body cloth and a liner cloth of a flexible container bag according to the present invention.

FIG. 2 is a cross-sectional view of another embodiment of the joint portion between the main body cloth and the lining cloth of the flexible container bag according to the present invention.

FIG. 3 is a cross-sectional view of a joint portion between a main body cloth and a lining cloth of a conventional flexible container bag.

[Explanation of symbols]

1 main body cloth 2 lining cloth 3 welded section 4 peeling stress action end section 5 and 8 waterproof waterproof over tape 6 shielding sheet 7 sewing machine sewing

Claims (2)

[Claims] 1. A flexible container bag having a lining cloth for retaining its shape inside a bag body, wherein the body cloth and the lining cloth are welded together, and the welded portion of the body cloth and the lining cloth is peeled off. A sewing machine is sewn on the end boundary line on the side where the stress acts, and a sealing waterproof over tape is welded on the sewing machine sewn surface from both the main body cloth surface and the lining cloth surface. Flexible container bag. 2. The flexible container bag according to claim 1, wherein the sewing machine is sewn with a shielding sheet interposed on an end boundary line on the side where the peeling stress acts between the main body cloth and the lining cloth.