JPH0880995A - Flexible container bag - Google Patents

Abstract

(57) [Summary] [Purpose] A cubic container or a 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, and the bag body. The present invention relates to a joint structure having improved joint strength with an lining cloth provided inside. In a flexible container bag having a lining cloth for holding a shape inside a bag body, a heat-adhesive intermediate member is interposed at a joint portion between the body cloth and the lining cloth to form a bag body cloth. The intermediate member is welded over the entire area, and the lining cloth and the intermediate member are welded to each other, leaving an unbonded portion at the peeling action side end of the intermediate member, and the bonded portion and the unbonded portion between the lining cloth and the intermediate member. A flexible container bag in which a sewing machine is sewn on a boundary line between the sewing machine and a shielding sheet, and a sealing waterproof over tape is welded on the sewing thread.

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, and more particularly, to a flexible container bag. 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 is a very important issue for the flexible container bag. That is,
Flexible container bags, which are used as powdery or granular transport bags for foods, grains, fertilizers, chemicals, or synthetic resins, have thermoplastic resin films laminated on both sides of stretched woven fabric made of thermoplastic resin. The bag is formed of a laminated sheet, and an inner corner portion of the side wall of the bag body is welded with a lining cloth for holding the shape for holding the shape, and a hanging belt is provided on the side wall. There is.

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, when joining the bag body and the lining cloth, etc., as shown in FIG. 4, both are directly welded. As a welding means, a laminated sheet is a 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 cross-sectional 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.

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. 4 has peeling stress at the welded portion when hot 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. Therefore, in order to improve the peeling strength between the main body cloth and the lining cloth, the present inventor intervenes an intermediate member having heat adhesiveness at the joint between the main body cloth and the lining cloth, and We proposed a joint structure for flexible container bags, characterized in that the intermediate member was welded over the entire area, and the lining cloth and the intermediate member were welded while leaving an unbonded portion at the peeling action side end of the intermediate member ( Japanese Patent Application No. 6-33862).

[0006]

According to the above proposal, it was possible to improve the drawback that the main body cloth and the lining cloth are peeled off and the original square shape of the bag is lost, but the peeling strength is further improved. As a result of various studies to make it possible, the present invention has been completed, and the present invention is a bag body 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, and a bag body thereof. An object of the present invention is to provide a flexible container bag with improved peel strength from the 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 the bag body, wherein a thermal adhesive property is provided at the joint between the main body cloth and the lining cloth. The bag body cloth and the intermediate member are welded over the entire area, and the lining cloth and the intermediate member are welded to each other, leaving an unbonded portion at the end on the peeling side of the intermediate member. A sewing machine is sewn on the boundary line between the bonded portion and the non-bonded portion of the cloth and the intermediate member, and the sewing thread for the sewing machine is used as a sealing waterproof
It is a flexible container bag characterized by welding a bar tape.

That is, in the present invention, an intermediate member is interposed between the body cloth and the lining cloth to be welded, the intermediate member and the bag body are welded over the entire area, and the intermediate member and the lining cloth are The peel strength was improved by welding the intermediate member with a non-bonded portion left, and sewing the boundary line between the bonded portion and the non-bonded portion of the intermediate member and the lining cloth with a sewing machine. If the sewing thread is exposed on the lining fabric surface, a sealing waterproof over tape is welded on it to prevent foreign matter such as lint from entering the contents of the bag. If the sewing thread is exposed on the outer surface of the bag body cloth, a sealing waterproof over tape is also welded on the outer surface of the bag body cloth, and the sewing thread is transmitted from the outside. Etc. are prevented from being mixed in the bag.

Further, a shielding sheet is provided between the lining cloth and the intermediate member.
It is preferable to perform sewing with a sewing machine interposed. By inserting the shielding sheet into this sewing area,
This is because it is possible to prevent the contents in the bag from coming into contact with the sewing thread and rubbing it to generate lint or the like, which causes foreign matter to enter. In the present invention, the unbonded portion between the intermediate member and the lining cloth varies depending on the size of the intended flexible container bag, but is approximately 2 to 20 mm from the peel stress acting side end of the intermediate member and less than 2 mm. It is meaningless to insert the intermediate member in the unbonded part, and if it exceeds 20 mm, the width of the bonded part between the intermediate member and the lining cloth becomes narrow, which may cause difficulty in shear strength.

The present invention will be described with reference to the drawings. 1 to 3 are sectional views of a joint portion of a flexible container bag of the present invention, and FIG. 4 is a sectional view of a joint portion of a conventional bag.
Conventionally, as shown in FIG. 4, the main body cloth 1 and the lining cloth 2 are simply welded. On the other hand, FIG. 1 and FIG.
In FIG. 1, the intermediate member 3 is welded onto the body cloth 1, and the lining cloth 2 is welded onto the intermediate member 3. Therefore, the main body cloth 1 and the intermediate member 3 are welded over the entire area, and the intermediate member 3 and the lining cloth 2 are welded while leaving the unbonded portion 4 on the peeling stress acting side. Then, the sewing machine is sewn with the sewing thread 5 on the boundary line between the bonded portion and the non-bonded portion of the lining cloth 2 and the intermediate member 3. In FIG. FIG. 2 shows a case where the lining cloth, the intermediate member, and the main body cloth are sewn with a sewing machine. In the case of FIG. 1, a sealing waterproof over tape 7 is welded onto the sewing thread 5 exposed on the lining cloth 2. In the case of FIG. 2, the sewing sewing thread 5 exposed on the lining cloth and the sewing thread 5 exposed on the main body cloth are respectively sealed with a waterproof overheater.
Weld No. 7 and 8.

FIG. 3 is a sectional view of another embodiment of the joint portion between the bag body cloth 1 and the lining cloth 2 of the flexible container bag of the present invention. FIG. 3 is a cross-sectional view of the case where sewing is performed by interposing a shielding sheet 6 at the end of the unbonded portion 4 on the side where the peeling stress acts on the welded portion of the lining cloth 2 and the intermediate member 3. . By inserting the shielding sheet into the sewing position of the sewing machine, it is possible to prevent the contents in the bag from contacting and rubbing against the sewing thread of the sewing machine to generate lint and the like, which may cause foreign matter to enter.

In the present invention, the laminated sheet which can be used as the body cloth and the liner cloth includes high density polyethylene, high density polyethylene and other thermoplastic resins such as linear low density polyethylene (LLDPE) and ethylene vinyl acetate. Low density polyethylene or linear low density polyethylene (LLDP) on both sides of a flat yarn laminated or blended with a copolymer (EVA), polypropylene or the like, or a woven fabric made of a multifilament yarn such as nylon or polyester.
E), ethylene vinyl acetate copolymer (EVA), polyvinyl chloride or the like having a thermally adhesive resin layer formed thereon,
For example, the main body cloth is a laminated sheet having a single-layer structure in which a thermoplastic resin film is laminated on both sides of a stretched woven cloth made of a thermoplastic resin, and the lining cloth is formed of a thermoplastic resin film at the central portion. And a laminated sheet having a multilayer structure in which a stretched woven fabric made of a thermoplastic resin and a thermoplastic resin film are laminated on both surfaces thereof is preferable.

As the intermediate member, a laminated sheet having a heat-adhesive resin layer formed on the surfaces of the main body cloth and the lining cloth and a surface layer capable of heat-adhesion and a thick film having a thickness of about 0.5 mm are used. To be done. As an example of the laminated sheet, a single layer laminated sheet in which a thermoplastic resin film having a thickness of about 50 μ is laminated on both sides of a stretched woven fabric, or a thermoplastic resin-based film as a central portion, and thermoplastic resin is formed on both sides thereof A laminated sheet having a multilayer structure in which a laminate of a stretched woven fabric made of a resin and a thermoplastic resin-based film is laminated so that the thermoplastic resin film at the center and the stretched woven fabric of the laminate are joined together is preferable. . The sealing waterproof over tape is preferably the same as the main body cloth with respect to the main body cloth surface, and a film or sheet that can be heat-welded with the lining cloth with respect to the lining cloth surface. Or a laminated product is preferable, and for the lining cloth surface, a film that can be heat-welded with the lining cloth,
Sheets or laminates are preferred. As the shielding sheet, a synthetic resin film, a sheet or a laminated product thereof is preferable. Further, as the sewing thread used for sewing, a polyester thread, a nylon thread, a polypropylene thread, a polyethylene thread, etc. are used, and as a sewing machine for sewing, a general industrial sewing machine is used.

As a means for welding the main body cloth and the intermediate member, and the intermediate member and the lining cloth, conventionally used, for example, heat bonding with a bar, heat bonding with hot air, or surface resin such as vinyl chloride. In the case of tarpaulins using
A bonding method such as a high frequency welder can be used. The method of joining the joined portions of the flexible container bag of the present invention is not particularly limited, but, for example, in the case of FIG. 2, the lining cloth and the intermediate member are welded while leaving a part of the intermediate member, Next, the intermediate member and the main body cloth are welded over the entire surface, and then sewing is performed, and a sealing waterproof over tape is welded on each sewing portion. In the case of FIG. 1, the lining cloth and the intermediate member are welded to each other while leaving a part of the intermediate member, sewing is performed, and then the entire surface of the main body cloth is welded. Next, the present invention will be specifically described with reference to examples.

[0015]

【Example】

Example 1 A flexible container bag made of a polyethylene cloth sheet in which a 2000-denier flat yarn made of high-density polyethylene was woven so that the warp and weft were each 15 yarns / inch and a LLDPE film having a thickness of 60 μ was laminated on both sides. Used as the body cloth of. Thickness 5 as lining cloth
A composite polyethylene cloth in which polyethylene cloth having the same structure as that of the main body cloth is adhered to both sides of a 0 μ LLDPE film, and the outer surface of the polyethylene cloth is covered with an LLDPE film having a thickness of 60 μ. A sheet was used.

As an intermediate member, two pieces of polyethylene cloth, which is a plain weave of 1000 denier high-density polyethylene flat yarn so that the warp and weft are 10 yarns / inch each, are adhered with an LLDPE film having a thickness of 50 .mu.m. A composite polyethylene cloth sheet whose both outer surfaces were coated with a 60 μm LLDPE film was used. The main body cloth and the lining cloth were heat-welded through the intermediate member having a width of 40 mm. The main body cloth and the intermediate member were hot-air welded over the entire width of 40 mm, and the intermediate member and the lining cloth were heat-welded by leaving an unbonded portion of 10 mm width from the end of the intermediate member on the peeling action side. Then, the intermediate member and the lining cloth were sewn along the boundary line between the bonded portion and the non-bonded portion of the intermediate member and the lining cloth.
The sewing thread used was polyester # 40 / # 40. A sealing waterproof over tape was welded on the sewing thread exposed on the lining 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.

Example 2 The same main body cloth and lining cloth as in Example 1 except that the main body cloth and the lining cloth were sewn along the boundary line between the bonded portion and the non-bonded portion of the intermediate member and the lining cloth, Using the intermediate member and the sewing thread, heat welding and sewing were performed under the same conditions. Then, a sealing waterproof over tape was welded on each of the sewing thread exposed on the lining cloth surface and the main body cloth surface. The peel strength of the obtained joint was measured, and the results are shown in Table 1.

[0018]

[Table 1]

[0019]

As described above, in the present invention, the intermediate layer is interposed between the main body cloth and the lining cloth, leaving the unbonded portion on the stress acting side, and the bonded portion and the unbonded portion are provided. By sewing with the sewing machine along the boundary line of the flexible container bag, as shown in Table 1, a flexible container bag having a larger peel strength than that of the conventional method can be obtained. The shape can be maintained, and therefore, stacking strength can be improved, 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 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. 4 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 body cloth 2 lining cloth 3 intermediate member 4 unbonded portion 5 sewing thread 6 shield sheet 7 and 8 sealing waterproof over tape

Claims (4)

[Claims] 1. A flexible container bag having a lining cloth for holding a shape inside the bag body, wherein a main body cloth and the lining cloth are joined together with an intermediate member having a heat adhesive property interposed therebetween. The cloth and the intermediate member are welded over the entire area,
The lining cloth and the intermediate member are welded to each other, leaving an unbonded portion at the peeling action side end of the intermediate member, and a sewing machine is sewn on the boundary line between the bonded portion and the unbonded portion between the lining cloth and the intermediate member. A flexible container bag in which a sewing over sewing thread is sealed and a waterproof over tape is welded. 2. The flexible container bag according to claim 1, wherein the main body fabric is a laminated sheet having a single layer structure in which a thermoplastic resin film is laminated on both sides of a stretched woven fabric made of a thermoplastic resin. 3. The lining cloth has a thermoplastic resin film as a central portion, and a laminate of a stretched woven fabric made of a thermoplastic resin and a thermoplastic resin film on both sides of the thermoplastic resin film as a central portion. The flexible container bag according to claim 1, which is a laminated sheet having a multilayer structure in which a laminated woven fabric is laminated so as to be bonded to the laminated woven fabric. 4. The flexible container bag according to claim 1, wherein a sewing machine is sewn with a shielding sheet interposed on a boundary line between a bonded portion and an unbonded portion between the lining cloth and the intermediate member.