CA1171822A - Reinforced gusseted bag and method for manufacturing - Google Patents

Reinforced gusseted bag and method for manufacturing

Info

Publication number
CA1171822A
CA1171822A CA000348718A CA348718A CA1171822A CA 1171822 A CA1171822 A CA 1171822A CA 000348718 A CA000348718 A CA 000348718A CA 348718 A CA348718 A CA 348718A CA 1171822 A CA1171822 A CA 1171822A
Authority
CA
Canada
Prior art keywords
bag
side walls
center line
define
plastic bag
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.)
Expired
Application number
CA000348718A
Other languages
French (fr)
Inventor
George F. Kirkpatrick
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.)
Union Carbide Corp
Original Assignee
Union Carbide Corp
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 Union Carbide Corp filed Critical Union Carbide Corp
Application granted granted Critical
Publication of CA1171822A publication Critical patent/CA1171822A/en
Expired legal-status Critical Current

Links

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B65CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65DCONTAINERS 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
    • B65D31/00Bags or like containers made of paper and having structural provision for thickness of contents
    • B65D31/10Bags or like containers made of paper and having structural provision for thickness of contents with gusseted sides

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Bag Frames (AREA)
  • Making Paper Articles (AREA)

Abstract

REINFORCED GUSSETED BAG
AND METHOD FOR MANUFACTURING

ABSTRACT OF THE DISCLOSURE

A plastic bag of a heat sealable material includes a gusseted portion and a spot heat sealed region joining together all four of the layers for reinforcing the gusseted portion.

S P E C I F I C A T I O N

1.

Description

~1718~Z

The inventiDn relates to a plastic bag of a heat sealable material including a g~sseted portion.
Methods for making bottDm and side gusseted plastic bags are well-known in the art. The fDllowing patents show some of the typical prior art methods for making gusseted plastic bags and these patents are incorporated herein by reference. These patents include U.S. patent no. 4,046,065, U. S. patent no.
3,980,225, U. S. patent no. 3,319,540, U. S. patent no.
3,395,622, and U. S~ patent no. 3,839,128.
In the pri~r art, it was fount that the bottDm gussetet plastic bags had two weak points, one at each of the intersections of the center llne fold of the gusset ant the site edges. One prlor srt solut~on to this problem has been the use of diagonal heat seal regions extenting from the weak points town to the bottom of the bag at an angle to the bag bottom. The diagonal heat seals can have two different forms. If the tiagonal heat seal ~oins together the four layers of the bag, then the gusset becomes restricted and the bag cannot be opened fully 90 that the bag capacity as well as the stant-up qualities of the bag becomes impaired.
If the diagonal heat seals are mate to seal only the two adjacent layers of the bag rather than all fDur layers, a separator plate must be used in the sealing process. The use of a separator plate between the layers
2.

-~ 12318 13 7~8~Z

keeps the diagonal heat seal from reaching and reinforcing the weak seal points so that the effectivenes~ of the diagonal seal is not fully obtainable. Furthermore, the use of a separator plate requires that the heat sealing be separately accomplished on each side of the bag so that an increase in equipment and manufacturing costs results.

Similarly, weak points have been found in side gusseted bags and these have been dealt with by the use of diagonal heat sealing also.

The instant invention can be carried out economically and is surprisingly effective in improving the strength of the gusseted plastic bag.
One of the embodiments of the instant invention i8 a plsst~c bag compr~9ing two side walls of a heat sealable material, the side walls being connected together by an inwardly folded portion of material which is folded along a center line fold and outer line folds to define a gusseted portion, the side walls being heat sealed together at least along an edge generally perpendicular to the center line fold to define the bag, and a spot heat sealed region spaced from the outer line folds and located at the intersection of the center line fold and the edge for joining together all our of the layers of the material.

Another embodiment of the instant invention is a plastic bag comprising two side walls of a heat sealable material, the side walls being connected together by an inwardly folded portion of material which is folded along a longitudinal center line fold to define a gusseted bottom, the side walls being heat sealed together along opposite sides of the bag to define side edges of the bag, and a spot heat sealed region spaced from the bottom of the bag and located at each of the intersections of the center line fold and the side edges for joining together all four of the layers of the material.
Generally, each spot heat sealed region is preferably a semi-circle positioned with a diameter along the side edge and substantially bisected by the center line fold. Other shapes for the heat sealed region can be used such as rings, triangles, hexagons, other polygons, etc.
The plastic bag can include a closure device suitable for opening and closing the bag in accordance with the prior art or as shown in U. S. Patent 4,212,337 issued July 15, 1980 and assigned to the assignee of the instant application.
;Another embodiment of the invention is a metho~ of forming a reinforced gusseted plastic bag, comprising ;the steps of supplying heat sealable material, inwardly folding a portion of the material along a center line fold ';

4.
,~

f ` ~

1 ~ 7 ~ 8 ~ ~

and outer line folds to define a gusseted portion, and heat sealing at least along an edge generally perpendicular to the center line fol.d to define the bag, wherein the ¦ improvement comprises spot heat sealing a region spaced fr~m the outer line folds located at the intersection - of the center line fold and the edge for joining together all four of the layers of the material.
Another embodiment of the invention isa method of forming a reinforced bottom gusseted plastic bag, compris-, 10 ing the steps of supplying a heat sealable plastic film web in the form of a continuous sheet having substantially parallel sheet etges, folding the film web so that the ; sheet edges of the film web are near each other and substantially paralle~ to each other, inwartly folting a portion of the film web to establish a longitutinal center line fold to define a gusset, spot heat sealing regionsto ~oln together all four layers of the material at spaced locations along the center line folt, and sever-sealing the film web transversely to intercept the heat sealet regions to tefine side etges for the bag.
Preferably, the heat sealed regions are spaced apart a predétermined distance equal to the width of the bag and preferably the heat sealed regions are circular.

11718?.2 The invention accordingly comprises the features of construction, the combination of elements and the arrangement of parts which will be exemplified in a construction hereinafter set forth and thè scope of the application of which will be indicated in the cla~ms.
The invention also comprises the several steps in the relationship of one or more of such steps with respect to each of the others, all as exemplified in the following detailed disclosure and the scope of the 10 application of which will be indicated in the claims.
For a fuller understanding of the nature and ob~ects of the invention, reference should be had to the following tetailet description, taken in connection with the accompanying drawings, in which:
Fig. 1. ls a front elevational view of a plastic bag in accortance with the invention;
Fig. 2 is a sectional view along the line 2-2 of Fig. l;
Fig. 3 is a perspective view of the plastic bag of Fig. l in an open state;
Fig. 4 is a block tiagram of the apparatus for carrying out the method of the invention; ant Fig. 5 shows a portion of the operations Rhown in Fig. 4, ant Fig. 6 is a front elevational view of another plastic bag in accordance with the invention.

6.

~ 8 ~ Z

In carrying the invention into effect, certain embodiments have been selected for illustration in the accompanying drawings and for descrip~ion in the specifica-tion, reference being had to Figs. 1 to 6.
A plastic bag in accordance with the instant invention optionally includes a closure device at the opening of the bag. Fig. 1 shows one embodiment of the invention which includes a closure device 10. The side walls 11 are of a heat sealable material and the gusseted bottom 12 can be seen from Fig. 2 as being an inwardly folded portion of the material which is folded along a longitudinal center line fold 13 and outer line folds 15.
In accordance with prior art practice, the side edges 14 are formed by a sever-sealing operation.
The spot heat sealed regions 16 are located at the intersections of the center line fold 13 and the side edges 14 in order to provide reinforcement for the gusseted bottom 12, particularly when the bag is opened and loaded and the gusset bottom 12 is stressed.
The heat sealed regions 16 ~oin together the four layers of the gusseted bottom 12 as can be appreciated by reference to Figs. 2 and 3.

'` 12318 ~171.8;22 Fig. 4 shows a block diagram of the apparatus for carrying out the method of the invention for producing a plastic bag in accordance with the invention. Generally, the production of a plastic bag having a gusseted bottom i8 known from the prior art.
Plastic film webs 17 is supplied, for example, from a roll 18 of the heat sealable material. In its simplest form, the pla8tic film web 17 can be a single layer. PLastic film web 17, h~wever, could also be a multiLayer film web,provided that both of the outsidè
layers are heat sealsble 80 that the plastic bag of the invention can be formed. Unit 19 folds the film web 17 in half and forms an inwardly folted portion along a longitudinal center line to tefine a gusset portion. Unit 19 is well-known from the prior art,such a9 U.S. patent no. 3,059,549. Preferably the film web 17 i~ folded in half, but it may be desirable for certain ùse~ to fold the film web 90 that the plastic bag finally obtained will have one side wall extending beyont the other site wsl}.
The folded film web 21 from unit 19 can have a closure device bonded to it in unit 22 in accord-nce with prior art mRthods, or 8 directly to unit 23 for ~pot heat sealing regions for reinforcing the gusseted bottom.
The method of establishing spot heat sealing is well-known in the prior art. The spot heat sealing regions 25 are .

:1~7~8~2 - spaced apart a distance equal to the width of the bags being produced. The spot heat sealed film web 24 is thereafter sever-sealed in unit 26 to produce the plastic bag acccrding to the lnventLon.
Fig. 5 shows the spot heat sealed film web 24 which is moved into the unit 26,and bag 27 which is eject by the unit 26. The sever-sealing operations substant~al bisect the spot hea~t sealed regions 25 as shown in Fig. 5 . The surprising improvement obtained by the instant invention can be appseciated by the following test results.
Bottom gusseted bags were made in the so-called "5 quart size". The bags were made from low tensity polyethylene fil~ having a thickness of 1.75 mii.
The dimensions were 10-1/2 inches wide and 11 inches dee with a bottom gusset 2 inches deep. The bags included interlocking closures. Of the 104 bags, half were in accordance with the invention while the other half did n $nclude reinforcing and were according to prior art.
Each bag was loaded with a liter of water, se led wlth the lnterlocking closure, and dropped ln an upright position from a heigh~ of 4 feet onto a hard surface. Thereafter, each bag was inspected for damage The 52 bags according to the invention had a single bag failure while the 52 bags according to the -1~7~8;2Z

prior art had 10 bag failures.
These results show that the bags according to the invention are substantially superior to the prior art bags without the spot heat sealing reinforcing.
Fig. 6 shows another embodiment of the invention for a plastic bag having side gussets. The side walls 30 are of a heat sealable material. The gusseted sides 31 have been formed by inwardly folding the material along center line folds 32 and outer line folds 33. In accordance with prior art practice, an edge seal 34 is formed with a skirt 36. The spot heat sealed regions 37 are located at the intersections of the center line folds 32 and the edge seal 34 in order to provide reinforcement for the respective gusseted sides 31.
It i8 understood that the invention i9 not limlted to the exact details of construction shown and describet, for obvious modifications will occur to a person skillet in the art.
Having thus tescribet the invention, what is claimet a~ new ant desired to be secured by Letters Patent, is as follows: ~

10.

Claims (19)

WHAT IS CLAIMED IS:
1. A plastic bag comprising two side walls of a heat sealable material; said side walls being connected together by an inwardly folded portion of material which is folded along a center line fold and outer line folds to define a gusseted side portion of said bag; said side walls being sever-sealed to provide a thermally welded and sealed edge seam interposed between and substantially abuttingly joining adjacent edge extremities of said side walls, said seam being generally perpendicular to said outer line fold to define said bag; and a spot heat sealed region spaced from said outer line folds and located at the intersection of said center line fold and said sever-sealed edges for joining together all four of the layers of the material.
2. The plastic bag of claim 1, wherein said spot heat sealed region has the shape of at least a portion of a circle.
3. The plastic bag of claim 1, wherein said spot heat sealed region has the shape of a triangle or rectangle or other polygon.
4. The plastic bag of claim 1, wherein said spot heat sealed region has the shape of a semi-circle and is positioned with the diameter of said semi-circle along said edge.
5. A plastic bag comprising two side walls of a heat sealable material; said side walls being connected together by an inwardly folded portion of material which is folded along a longitudinal center line fold to define a gusseted bottom of said bag; said side walls being sever-sealed together along 11.

opposite sides of the bag to define side edges of the bag and provide a thermally welded and sealed side edge seam interposed between and substantially abuttingly joining adjacent side edge extremities of said side walls; and a spot heat sealed region spaced from the bottom of the bag and located at each of the intersections of said center line fold and said sever-sealed side edges for joining together all four of the layers of said material.
6. The plastic bag of claim 5, wherein said spot heat sealed region has the shape of at least a portion of a circle.
7. The plastic bag of claim 5, wherein said spot heat sealed region has the shape of a semi-circle and is positioned with the diameter of the semi-circle along the proximate side edge.
8. The plastic bag of claim 5, wherein said heat sealed region has the shape of a triangle or rectangle or other polygon.
9. A plastic bag comprising two side walls of heat seal-able material; said side walls being connected together at opposite sides by inwardly folded portions of material each of which is folded along a center line fold and outer line folds to define gusseted sides; said side walls being heat sealed together to define a bottom edge; and a spot heat sealed region spaced from said outer line folds and located at each of the intersections of said center line fold and said bottom edge for joining together all four of the layers of said materials.

12.
10. The plastic bag of claim 9, wherein said bag includes a skirt portion extending beyond said bottom edge.
11. The plastic bag of claim 9, wherein said spot heat sealed region has the shape of at least a portion of a circle.
12. The plastic bag of claim 9, wherein said spot heat sealed region has the shape of a triangle or rectangle or other polygon.
13. A method of forming a reinforced gusseted plastic bag, comprising the steps of supplying heat sealable material;
inwardly folding a portion of the material along a center line fold and outer line folds to define a gusseted portion; and heat sealing at least along an edge generally perpendicular to said center line fold to define a bag; wherein the improvement comprises spot heat sealing a region spaced from said outer line folds and located at the intersection of said center line fold and said edge for joining together all four layers of said material.
14. A method of forming a reinforced bottom gusseted plastic bag, comprising the steps of supplying a heat sealable plastic film web of a continuous sheet having substantially parallel sheet edges; folding said film web so that the sheet edges of said film web are near each other and substantially parallel to each other, inwardly folding a portion of said film web to establish a longitudinal center line fold to define a gusset; spot heat sealing regions to join together all four layers of said material at spaced apart locations along said center line fold, and sever-sealing said film web transversely to intercept said heat sealed regions to define side edges for said bag.

13.
15. The method of claim 14, further comprising the step of connecting a closure device to said film web so that said bag is produced as a reclosable bag.
16. The method of claim 14, wherein said spot sealing regions have the shape of a circle and the sever-sealing step substantially bisects said spot sealing regions.
17. The method of claim 14, wherein said spot sealing regions have the shape of triangles or rectangles or other polygons.
18. A plastic bag comprising a closure device located near the opening of said bag and two side walls of a heat sealable material; said side walls being connected together by an inwardly folded portion of material which is folded along a center line fold and outer line folds to define a gusseted side portion of said bag; said side walls being sever-sealed to provide a thermally welded and sealed edge seam interposed between and substantially abuttingly joining adjacent edge extremities of said side walls, said seam being generally perpendicular to said outer line fold to define said bag; and a spot heat sealed region spaced from said outer line folds and located at the intersection of said center line fold and said sever-sealed edges for joining together all four of the layers of the material.
19. A plastic bag comprising a closure device located near the opening of said bag and two side walls of a heat sealable material; said side walls being connected together by 14.

an inwardly folded portion of material which is folded along a longitudinal center line fold to define a gusseted bottom of said bag; said side walls being sever-sealed together along opposite sides of the bag to define side edges of the bag and provide a thermally welded and sealed side edge seam inter-posed between and substantially abuttingly joining adjacent side edge extremities of said side walls; and a spot heat sealed region spaced from the bottom of the bag and located at each of the intersections of said center line fold and said sever-sealed side edges for joining together all four of the layers of said material.

15.
CA000348718A 1979-03-30 1980-03-28 Reinforced gusseted bag and method for manufacturing Expired CA1171822A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US2566079A 1979-03-30 1979-03-30
US025,660 1979-03-30

Publications (1)

Publication Number Publication Date
CA1171822A true CA1171822A (en) 1984-07-31

Family

ID=21827352

Family Applications (1)

Application Number Title Priority Date Filing Date
CA000348718A Expired CA1171822A (en) 1979-03-30 1980-03-28 Reinforced gusseted bag and method for manufacturing

Country Status (14)

Country Link
AU (1) AU539227B2 (en)
BE (1) BE882516A (en)
CA (1) CA1171822A (en)
CH (1) CH637078A5 (en)
DE (1) DE3011442A1 (en)
DK (1) DK136080A (en)
FI (1) FI800958A (en)
FR (1) FR2452434B1 (en)
GB (1) GB2047199B (en)
IT (1) IT1188983B (en)
NL (1) NL8001858A (en)
NO (1) NO800863L (en)
NZ (1) NZ193294A (en)
SE (1) SE8002383L (en)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE8803021U1 (en) * 1988-03-05 1988-06-01 Rovema - Verpackungsmaschinen Gmbh, 35463 Fernwald bag
US5080643A (en) * 1988-03-21 1992-01-14 Dow Brands Inc. Method of making a stand-up plastic bag
US4954124A (en) * 1988-03-21 1990-09-04 The Dow Chemical Company Stand-up plastic bag and method of making same
US4837849A (en) * 1988-03-21 1989-06-06 The Dow Chemical Company Stand-up plastic bag and method of making same
US4904093A (en) * 1988-08-24 1990-02-27 The Dow Chemical Comapny Gussetted plastic bags having relief seals and method of making same
GB2360271B (en) * 1998-07-08 2002-09-11 Flexipol Packaging Ltd Bags of easy open construction
IES20030895A2 (en) * 2003-11-28 2005-05-18 Steripack Medical Ltd Process for manufacturing packaging pouches

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE629755A (en) *
GB915724A (en) * 1959-09-25 1963-01-16 Hienz Guelker Improvements in or relating to methods for the production of containers
CH385616A (en) * 1961-09-30 1964-12-15 Natro Cellulosa S P A Single sheet plastic bag
FR1465623A (en) * 1965-12-01 1967-01-13 Cie Ind Des Textiles Et Emball Method and device for sealing gusseted plastic bags in a direction perpendicular to the gussets
GB1331434A (en) * 1969-12-16 1973-09-26 Fisons Ltd Sacks

Also Published As

Publication number Publication date
IT8048275A0 (en) 1980-03-27
FR2452434A1 (en) 1980-10-24
GB2047199B (en) 1983-02-16
DE3011442A1 (en) 1980-10-02
CH637078A5 (en) 1983-07-15
SE8002383L (en) 1980-10-01
FR2452434B1 (en) 1985-12-06
AU5693780A (en) 1980-10-02
BE882516A (en) 1980-09-29
IT1188983B (en) 1988-01-28
NO800863L (en) 1980-10-01
NL8001858A (en) 1980-10-02
GB2047199A (en) 1980-11-26
DK136080A (en) 1980-10-01
AU539227B2 (en) 1984-09-20
FI800958A (en) 1980-10-01
NZ193294A (en) 1982-12-21

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