Flexible bags – Bag closure secured by a releasable or frangible bond – Having another independent closure for same access opening
Patent
1997-05-12
1999-01-19
Garbe, Stephen P.
Flexible bags
Bag closure secured by a releasable or frangible bond
Having another independent closure for same access opening
53451, 383 84, B65D 3324
Patent
active
058607447
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The invention relates to a bag made of a flexible packing material by folding a sheet of material having an inner face and an outer face and comprising a pouch portion having a front wall and a back wall and a flap extending from the back wall and folded down onto the front wall about a folding line being essentially aligned with the upper free edge of the front wall, the inner face of the front wall being sealed to the inner face of the back wall at the side edge portions of the bag by means of the side edge seals, and the inner face of the flap being sealed to the outer face of the front wall by means of a longitudinal welding seam and by means of sealing seams at the side edge portions for obtaining a closed bag enclosing a packed product, seen relative to the bag said packing providing a peel seal when welded inner face to outer face, and a strong seal (fusion seal) when welded inner face to inner face.
BACKGROUND ART
DK-B-109 591 discloses a bag of the type stated in the introduction formed as a tobacco pouch having a pouch portion formed by folding a flexible packing material onto itself, and a flap folded down over the pouch portion. The inner face of the flap is welded or adhered peelably to the outer face of the pouch portion by means of a longitudinal weld, while the inner faces of the opposite walls of pouch portion and the flap are welded together in a non-peelable manner. This is obtained by using a packing material having a heat sealable first surface providing a fusion seal, when sealed onto itself, and a second surface providing a peel seal, when sealed onto the heat sealable surface of the packing material.
As examples of possible combinations of the two surfaces of the packing material polyethylene and vellum paper as well as polyethylene and aluminium foil are mentioned. When sealing polyethylene to vellum paper, a gas-proof packing cannot be obtained due to the structure and surface of the latter material. When sealing polyethylene to aluminium foil, an adhesion is obtained, whose strength is very difficult to control. In said publication it is therefore suggested to use an adhesion seal between the two materials of the mentioned combination of material.
The bags are made as single-bags, which are open at one side edge, i.e. only the longitudinal peel seal and one of the non-peelable seals are made, whereafter the prefabricated bags are filled with the desired product and the second strong side seal is provided. This method does not meet the requirements of today for a rational packing of products.
Peelable bags made on automatic form and fill machines are known. However, in these known bags the peelable seal is a side edge weld, i.e. the weld on which the product falls, when it is filled into the partly finished packing. This causes major problems, as the weld has to have such a strength when hot (hot tack strength) that it does not break, when the product falls thereon, but at same time it should be peelable when cold.
Finally, it should be mentioned that packing materials are known having a first outer layer of a copolymer of a polyethylene and polypropylene and a second outer layer of a polyethylene-containing polymer.
DISCLOSURE OF THE INVENTION
The object of the present invention is to provide a bag of the type stated in the introduction satisfying the demands of today for rational packing of products in a gas- or vacuum-proof, peelable bag.
The bag according to the invention is characterised in that seen relative to the bag the packing material comprises an inner layer comprising polyethylene (PE), an outer layer comprising a copolymer of polyethylene (PE) and polypropylene (PP) and a subjacent intermediate layer comprising polypropylene (PP).
By using a polymer-containing polyethylene in both the inner and the outer layer, in addition to obtaining a gas-proof strong seal when welding inner face to inner face, i.e. the PE-containing layer is welded onto itself, it is possible when welding inner face to outer face to provide a gas-proof seal and to control t
REFERENCES:
patent: 3412771 (1968-11-01), Ralph
patent: 3552638 (1971-01-01), Quackenbush
patent: 3596828 (1971-08-01), Foster et al.
patent: 3655503 (1972-04-01), Stanley et al.
patent: 3838549 (1974-10-01), Pepmeier
patent: 4252846 (1981-02-01), Romesberg et al.
patent: 4705174 (1987-11-01), Goglio
patent: 4744673 (1988-05-01), Nakamura
patent: 4785933 (1988-11-01), Focke
patent: 4944409 (1990-07-01), Busche et al.
patent: 5128414 (1992-07-01), Hwo
patent: 5181610 (1993-01-01), Quick et al.
Danisco A/S
Garbe Stephen P.
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