GB2116144A - Bags or sacks - Google Patents

Bags or sacks Download PDF

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Publication number
GB2116144A
GB2116144A GB08306169A GB8306169A GB2116144A GB 2116144 A GB2116144 A GB 2116144A GB 08306169 A GB08306169 A GB 08306169A GB 8306169 A GB8306169 A GB 8306169A GB 2116144 A GB2116144 A GB 2116144A
Authority
GB
United Kingdom
Prior art keywords
sack
porous
seam
ply
moisture barrier
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB08306169A
Other versions
GB8306169D0 (en
GB2116144B (en
Inventor
Bernard Sidney Baker
Douglas George James Nicholson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
DRG UK Ltd
Original Assignee
DRG UK Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by DRG UK Ltd filed Critical DRG UK Ltd
Priority to GB08306169A priority Critical patent/GB2116144B/en
Publication of GB8306169D0 publication Critical patent/GB8306169D0/en
Publication of GB2116144A publication Critical patent/GB2116144A/en
Application granted granted Critical
Publication of GB2116144B publication Critical patent/GB2116144B/en
Expired legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D33/00—Details of, or accessories for, sacks or bags
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D31/00—Bags or like containers made of paper and having structural provision for thickness of contents
    • B65D31/02—Bags or like containers made of paper and having structural provision for thickness of contents with laminated walls

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Bag Frames (AREA)

Abstract

A multi-ply sack has at least one moisture barrier ply or coating 5, 13 which is interrupted at a porous region 8, 15 through which under certain conditions of the sack air may escape from the interior of the sack, the arrangement being such that when the sack is filled the weight of its contents serves to block off or reduce the effectiveness of the porous region. Two porous regions 8, 15 may be provided in different plies 1, 2 and staggered with respect to one another. A porous region 15 may be provided in a reversely folded seam 12 so that when the seam 12 is not flattened air may escape through the porous region 15, but when the seam is flattened the porous region 15 is effectively blocked off. The ply 1 preferably comprises a low stretch crepe layer 3 a bitumen coating 5 and a layer 6 of spun-bonded polypropylene, and the ply 2 preferably comprises a low stretch crepe layer 9 with a polyethylene coating 13. <IMAGE>

Description

SPECIFICATION Bags or sacks This invention relates to multi-ply bags or sacks (hereinafter referred to for convenience as sacks), composed of paper, plastic, plastic film or other porous or non-porous material, and is concerned, more particularly, with such sacks which have a moisture barrier in the form of one or more plies or coatings for protecting the contents of the sack during transport and storage against moisture in the air.
Whilst such a moisture barrier is effective for the above purpose, it does have the effect of trapping air inside the sack with the conse quest disadvantage that the sack takes longer to fill, (which is usually performed through a sack valve), some of the contents of the sack may be blown out of the sack at the end of the filling operation when the sack is removed from the filling spout, and the sack must be made larger than the volume of the intended contents.
Various attempts have been made to provide a sack which on the one hand is moisture proof and on the other will allow entrapped air to escape, but none has been properly effective.
It is an object of the present invention to provide an improved sack in which the abov'e difficulties are effectively reduced.
The present invention consists in a rnulti-ply sack having at least one moisture barrier ply or coating which is interrupted at a porous region through which under certain conditions of the sack air may escape from the interior of the sack, the arrangement being such that when the sack is filled the weight of its contents serves to block off or reduce the effectiveness of ths porous region.
In one form of the invention, the sack has at least two moisture barrier plies or coatings each of which is interrupted at a porous region, the two porous regions being provided in different plies and staggered with respect to one another, and the arrangement being such that when the plies of the sack are brought into close contact with each other, the porous regions are effectively blocked off.
The inner ply of the sack may be provided with a reversely folded seam and the porous region, or one of the porous regions, is provided in the seam so that during filling when the seam is not flattened air may escape through the porous region, but when the seam is flattened the porous region is effec- tively blocked off.
In carrying the invention into effect according to one convenient msde by way of example, the accompanying drawing SilOWS diagrammatically a cross-section through part of a sack having composite outer and inner plies 1 and 2 respectively.
The composite outer ply 1 is composed of an outer ply 3 of low stretch crepe secured to itself with paper adhesive 4 to form a sack tube with an overlapping seam 11, and is provided with a moisture barrier in the for,n of an inner coating 5 of bitumen and a reinforc ing layer 6 of spun-bonded polypropylene secured to itself by p.v.a. adhesive 7 to form an inner reinforcing tube. The bitumen coat ing 5 does not extend to the end margin of the crepe ply 3 so that the moisture barrier is interrupted to provide a longitudinal porous region 8 over which the composite outer ply is composed only of crepe and spun bonded polypropylene both of which are porous so as to provide an air path A through which air can escape from the interior of the sack.
The composite inner ply 2 is composed of an inner ply 9 of low-stretch crepe secured to itself with paper adhesive 10 to form a sack tube with a reversely folded seam 1 2 and is provided with a moisture barrier in the form of a coating 1 3 of polyethylene. The coating 1 3 stops at 14 just inside the folded seam 1 2 so that when the seam 1 2 is not completely flattened the moisture barrier is interrupted to provide a longitudinal porous region 1 5 com posed of the uncoated crepe so as to provide an air path B through which air can escape from the interior of the sack.If and when the folded seam 112 is fiattened, then an effec lively complete moisture barrier for the inner ply 2 is formed by the coating 1 3.
The two porous regions 8 and 1 5 are staggered with respect to one another so that when the sack is filled and the weight of its contents causes the two plies 1 and 2 to be brought into close contact and the seam to be flattened both porous regions which provided the air paths A and B are closed to provide effectively continuous moisture barriers.
Various modifications may be made within the scope of the present invention. For example, the folded seam 1 2 may be replaced by an overlapping seam and various shapes and positions may be adopted for the porous regions. It may be effective in some cases to provide the two porous regions on opposite sides of the sack tube.
As a further alternative, the inner moisture barrier with the folded seam may be found to give sufficient protection in which case the outer moisture barrier may not be needed.
CLAiMS
1. A multi-ply sack having at least one moisture barrier ply or coating which is inter rupted at a porous region through which under certain conditions of the sack air may escape from the interior of the sack, the arrangement being such that when the sack is filled the weight of its contents serves to block off or reduce the effectiveness of the porous region.
2. A sack as claimed in claim 1, wherein
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Bags or sacks This invention relates to multi-ply bags or sacks (hereinafter referred to for convenience as sacks), composed of paper, plastic, plastic film or other porous or non-porous material, and is concerned, more particularly, with such sacks which have a moisture barrier in the form of one or more plies or coatings for protecting the contents of the sack during transport and storage against moisture in the air. Whilst such a moisture barrier is effective for the above purpose, it does have the effect of trapping air inside the sack with the conse quest disadvantage that the sack takes longer to fill, (which is usually performed through a sack valve), some of the contents of the sack may be blown out of the sack at the end of the filling operation when the sack is removed from the filling spout, and the sack must be made larger than the volume of the intended contents. Various attempts have been made to provide a sack which on the one hand is moisture proof and on the other will allow entrapped air to escape, but none has been properly effective. It is an object of the present invention to provide an improved sack in which the abov'e difficulties are effectively reduced. The present invention consists in a rnulti-ply sack having at least one moisture barrier ply or coating which is interrupted at a porous region through which under certain conditions of the sack air may escape from the interior of the sack, the arrangement being such that when the sack is filled the weight of its contents serves to block off or reduce the effectiveness of ths porous region. In one form of the invention, the sack has at least two moisture barrier plies or coatings each of which is interrupted at a porous region, the two porous regions being provided in different plies and staggered with respect to one another, and the arrangement being such that when the plies of the sack are brought into close contact with each other, the porous regions are effectively blocked off. The inner ply of the sack may be provided with a reversely folded seam and the porous region, or one of the porous regions, is provided in the seam so that during filling when the seam is not flattened air may escape through the porous region, but when the seam is flattened the porous region is effec- tively blocked off. In carrying the invention into effect according to one convenient msde by way of example, the accompanying drawing SilOWS diagrammatically a cross-section through part of a sack having composite outer and inner plies 1 and 2 respectively. The composite outer ply 1 is composed of an outer ply 3 of low stretch crepe secured to itself with paper adhesive 4 to form a sack tube with an overlapping seam 11, and is provided with a moisture barrier in the for,n of an inner coating 5 of bitumen and a reinforc ing layer 6 of spun-bonded polypropylene secured to itself by p.v.a. adhesive 7 to form an inner reinforcing tube. The bitumen coat ing 5 does not extend to the end margin of the crepe ply 3 so that the moisture barrier is interrupted to provide a longitudinal porous region 8 over which the composite outer ply is composed only of crepe and spun bonded polypropylene both of which are porous so as to provide an air path A through which air can escape from the interior of the sack. The composite inner ply 2 is composed of an inner ply 9 of low-stretch crepe secured to itself with paper adhesive 10 to form a sack tube with a reversely folded seam 1 2 and is provided with a moisture barrier in the form of a coating 1 3 of polyethylene. The coating 1 3 stops at 14 just inside the folded seam 1 2 so that when the seam 1 2 is not completely flattened the moisture barrier is interrupted to provide a longitudinal porous region 1 5 com posed of the uncoated crepe so as to provide an air path B through which air can escape from the interior of the sack.If and when the folded seam 112 is fiattened, then an effec lively complete moisture barrier for the inner ply 2 is formed by the coating 1 3. The two porous regions 8 and 1 5 are staggered with respect to one another so that when the sack is filled and the weight of its contents causes the two plies 1 and 2 to be brought into close contact and the seam to be flattened both porous regions which provided the air paths A and B are closed to provide effectively continuous moisture barriers. Various modifications may be made within the scope of the present invention. For example, the folded seam 1 2 may be replaced by an overlapping seam and various shapes and positions may be adopted for the porous regions. It may be effective in some cases to provide the two porous regions on opposite sides of the sack tube. As a further alternative, the inner moisture barrier with the folded seam may be found to give sufficient protection in which case the outer moisture barrier may not be needed. CLAiMS
1. A multi-ply sack having at least one moisture barrier ply or coating which is inter rupted at a porous region through which under certain conditions of the sack air may escape from the interior of the sack, the arrangement being such that when the sack is filled the weight of its contents serves to block off or reduce the effectiveness of the porous region.
2. A sack as claimed in claim 1, wherein the sack has at least two moisture barrier plies or coatings each of which is interrupted at a porous region, the two porous regions being provided in different plies and staggered with respect to one another, and the arrangement being such that when the plies of the sack are brought into close contact with each other, the porous regions are effectively blocked off.
3. A sack as claimed in claim 1 or 2, wherein the inner ply of the sack is provided with a reversely folded seam and the porous region or one of the porous regions, is provided in the seam so that during filling when the seam is not flattened air may escape through the porous region, but when the seam is flattened the porous region is effectively blocked off.
4. A sack as claimed in claim 1, 2 or 3, wherein the moisture barrier, or one or more of the moisture barriers, is provided by a nonporous coating upon a layer of porous material formed into a sack tube, the or each porous region being formed by an un-coated region of the porous material.
5. A sack substantially as described with reference to the accompanying drawing.
GB08306169A 1982-03-05 1983-03-07 Bags or sacks Expired GB2116144B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB08306169A GB2116144B (en) 1982-03-05 1983-03-07 Bags or sacks

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8206540 1982-03-05
GB08306169A GB2116144B (en) 1982-03-05 1983-03-07 Bags or sacks

Publications (3)

Publication Number Publication Date
GB8306169D0 GB8306169D0 (en) 1983-04-13
GB2116144A true GB2116144A (en) 1983-09-21
GB2116144B GB2116144B (en) 1985-10-23

Family

ID=26282181

Family Applications (1)

Application Number Title Priority Date Filing Date
GB08306169A Expired GB2116144B (en) 1982-03-05 1983-03-07 Bags or sacks

Country Status (1)

Country Link
GB (1) GB2116144B (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0144011A2 (en) * 1983-11-18 1985-06-12 Raackmanns Fabriker A/S A laminate to be used by the manufacture of packings containing products releasing gases
US5988881A (en) * 1997-06-18 1999-11-23 Bpb Plc Paper sack
EP1813545A1 (en) * 2006-01-26 2007-08-01 Mondi Packaging AG Multilayered paper sack.

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7850368B2 (en) 2004-06-04 2010-12-14 S.C. Johnson & Son, Inc. Closure device for a reclosable pouch

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0144011A2 (en) * 1983-11-18 1985-06-12 Raackmanns Fabriker A/S A laminate to be used by the manufacture of packings containing products releasing gases
EP0144011A3 (en) * 1983-11-18 1986-09-03 Raackmanns Fabriker A/S A laminate to be used by the manufacture of packings containing products releasing gases
US5988881A (en) * 1997-06-18 1999-11-23 Bpb Plc Paper sack
EP1813545A1 (en) * 2006-01-26 2007-08-01 Mondi Packaging AG Multilayered paper sack.

Also Published As

Publication number Publication date
GB8306169D0 (en) 1983-04-13
GB2116144B (en) 1985-10-23

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PCNP Patent ceased through non-payment of renewal fee