CA2043961A1 - Multiple ply bag with detachable inner seal pouch for packaging products - Google Patents

Abstract

ABSTRACT A tubular bag blank has a plurality of outer contiguous non-heat sealable plies and an inner heat sealable plastic ply. All of the plies in the tubular blank are bonded together circumferentially around an open top end of the bag and are closed at the bottom end where only the non-heat sealable plies are bonded together. The inner heat sealable ply is freely folded and fully detachable in a non-adhesive manner at the bottom end of the bag. The inner plastic ply being heat sealable to closure at both bag ends. Upon heat sealing the bottom end, a plastic pouch is formed by the inner ply which may be heat sealed to closure at the open end when filled with a product or commodity and may be optionally severed thereat by compressive heat and pressure applied to the outer non-heat sealable plies. When fully packed, the outer paper plies may be stripped away leaving a sealed plastic pouch with the packaged contents therein ready for use by the purchaser. 17

Description

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B_~ou~ na ~ y <;)1~ Inv0~a The invention pertain~ to a bag for the packaglng of product~
or commodities of the type having a sealed .inner pouch within a multiple ply enclosing bag, and methods for making the bag, and for ~illing and sealing the bag.
More particularly, the invention is directed toward an improvement in a multiwall bag of the type formed from a tubular flat blank.
The invention is also directed to the type of product packaye that includes a standard pinch bottom for the outer multiple plies at th~ bottom end of the bag. In this type o~ bag the commodity-holding pouch is formed from an inner plastic ply that is heat sealed at the pinch closure of the outer enclo_ing bag and open at the opposite end for receipt of a product to be packaged. Upon filling the bag to a desired amount, the inner plastic ply is heat sealed to close the open end and thereby create a sealed pouch which may remain detachably bonded to the top end o~ the outer plies or optionally might be severed to separate the plastic pouch ~rom the top end of the outer plies. In this r~gard the invention is further directed toward tho~e product bags wherein the ~ultiple outer plies are subsequently ~olded and bonded together at the top cut following the heat s~aling of the plastic ply.
The invention further provides for an improvement in multiwall type bags as described, which utilize an adhesive bonding, or equivalent, of the inner plastic ply to,the ~nnermost ply of the outer plies, whexein the outer plie~ comprise a plurality of contiguous overlying non-heat sealable plies bonded together.
The present invention is an improvement ~n the packaging arts which have heretofore evolved, such as that disclosed in U.S.
Patent No. 4,088,264, entitled "Multiwall Pouch Bags for Detached Packaging of Commoditiesl', issued May 9, 1978 to Vogt. In this patent, open ended, pinch botto~, multiwall bags are disclosed as having an inner ply o~ heat sealable plastic material, such as polyethylene, and one or ~oxe outer plie~ of a non;heat sealable ~ . ~ 2 ~

material, such as paper or equivalen~. The pla8ti¢ ply iS bond~d at both bag ends to the contiguous outer plies during bag manu~acturing and heat sealed and severed at the lower heat sealed zone during the bag bottoming operation. At the top opening of the bag, following the introduction of a product, commodity, or items, the plastic ply is heat sealed to closure and must be severed along the upper heat seal zone prior to closure of the outer plies. The result is a fully closed plastic bag inside of the ~ully closed paper bag. The problems that exist with thls de~ign are that when the unfilled bag is standing ready to be filled, the inner plastic bag is shorter in length than the enclosing outer paper bag. As the commodity is discharged or placed into the bag during the filling process there often are uneven and exces~ive pressures exerted on the lower plastic seal creating a potential for seal failure or pinhollng along the bottom heat seal zone. Alsn, a slight collapsing of the outer bag can be caused as th~ weight from the commodity ~orces the upper portion of the bag downward, thus creating problems with the integrity of the upper closure.
The present invention greatly reduces the possibility of bottom plastic seal failure, or bag collapse during the bag filling process, and offer~ signi~icant improvement over previously known techniques and bag constructions.

B~I~F 8~M~aRY OF T~B INV~TI~

The invention solves the foregoing problems in multiw~ll bag construct-ions and methods of making them by providing an inner plastic bag that is as long as the outer pap0r bag during the filling process. The bottom plastic seal is folded (wrapped~
around the pinch bottom fold line at the bag bot~om during ~he bag bottoming operation, but i~ not adhered or bonded to the contiguous outer plie~. Instead, it is loosely, or freely folded with the outer contiguou~ plies which provide~ for partial restraint thereat during filling by virtue of staying in place at the botto~ pinch closure. Therefore, the lower plastic heat seal is protect8d from ;-; 2 ~

excessive pressures during the bag ~illing process. Likewise, because the inner plas~ic pouch i5 a~ long a~ the outer paper bag, the probability of collapsing the upper portion o~ the bag during the bag ~illing process has been reduced, giving greater insurance of a proper closure o~ the open top bag end once the product or commodity ha~ been introduced.

BRI~F D~ACRIP~ION OF TB~ DRAWI~G~

The invention will be further described in detail with re~erence to the accompanying drawings wherein like reference numerals throuyhout re~er to the same elements and wherein Fig. 1 is a perspective, partially broken away, view of the multiply bag in accordance with the invention ready to be filled by the packer with a commodity or the like;
Fig. 2 is a horizontal cross section of the bag ~hown in Fig.
1 taken along the line 2-2 looking in the direction of the arrows;
Fig. 3 is a vertical cross sectional view oP the bag as shown in Fig. 1 taken along the line 3-3 looking in the direction of the arrows;
Fig. 4 is a vertical cross sectional view o~ a tubular bag blank which when subjected to the method steps of the present invention results in the bag as shown in Fig. l;
Fig. 5 shows the heat sealing at the lower end of the inner plastic ply of the blank as illustrated in Fig. 4 by the u~e of hot compression bars applied to the outer sur~aces of the ontisuous outer plies;
Fig. 6 is a vertical cross sectional view of the bag in accordance with th2 invention filled with a product and showing a heat sealing across a top zone of the inner plastic ply thereby forming a closed pouch;
Fig. 7 is a vertical cross sectional view of the filled bag showing an optional severance o~ th~ inner plasti~ ply during the heat sealing at the top sealing zone thereoi;

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Fig. 8 is a vertical cross sectlonal vlew o~ the upper portion of the filled bag illu~trating a heat~ng d~vice for lique~ying a hot melt adhesive previously applied to the upper ends o~ the outer plies;
Fig. 9 is a side view of the upper portion of the ~illed bag with the outer plies folded over for passage between two pressure rollers to close the bag;
Fig. lO is a sche~atic view of the sealing end closiny of the top end of the bag as illustrated in Figs. 6 9;
Fig. 11 is an elevational view o~ a ~illed and sealed bag having slits in the outer ply for the rPmoval o~ the contiguous outer plies;
Fig. 12 is a perspective view of a filled and sealed bag as in Fig. 11; and, Fig. 13 is a perspective view of the bag o~ Fig. 12 showing the filled and sealed plastic inner pouch with ~he contiguous outer plies stripped away.
taila~ Des~riptio~ o~ the I~entio~

Throughout the ~igures the re~erence numeral 10 is used to denote the bag made in conformance with the invention. In Fig. 1 the completed bag 10 in accordance wi'ch my invention will be seen to comprise an inner tubular ply 12 of heat sealable material, which may ba polyethylene, or equivalent, w~thin an outer tube 14 formed of a plurality of contiguou~ laterally of~set plie~ 1~, 18 and 20. The plies 16, 18, 20 are made of a non~heat sPalable material, such a.~ paper. With respect ~o the horizontal cro~s sectional view of the bag 10 shown in Fig. 2, it will be understood that the continuous plies 16, 18, 20 are laterally of~set so that vertical overlapping edge~ are ~paced iaterally around the bag 10 wherein ply 16 is overlapped at edges 16' 16n; ply 18 is overlapped at edges 18' 18t~ and ply 20 i8 overlapped a~ edges 20' 20~. The inner tubular ply 12 also i5 overlapped.~nd laterally o~fse~ a~ its edges 12' and 12~. The tubular formation i8 made in a blank ~orm a~3~ ~

22 illustrated in Fiy. 4, which blank is produced on known step end tuber devices. The inner pl~stic ply 12 is heat ~eal~d at the overlapping edges 12', 12" and the overlapping edges of the multiple non-heat sealable plies 16, 18, 20 are adhesively bonded thereat, such as by a hot melt adhesive applied in a known manner.
During the formation of the blank 22 ~he inner ply 12 is circumferentially bonded at 2~ at the top end thereo~ to the contiguous innermo~t paper ply 20. From the bond 2~ downwardly the inner ply 12 remains detached ~rom the outer tube 14 from 26 to 28 therealong. The outer contiguous paper plies 16, 18, 20 are bonded, pre~erably by dots of adhesive, at both the top and bottom ends of the blank 22 and indicated at 30, 32 in Fig. 1.
The blank 22 is subjected to the method steps of the present invention to result in the formation of the bag 10 shown in Figs.
1-3 as will now be explained. Attention is directed to Fig. 5 wherein a first s~ep is made ~y heat sealing the plastic ply 12 across a bottom closure zone 34 cau~ed by apply~ng heat bars 36, 38 at opposite sides of the outer contiguous non-heat sealable plies 16, 18, 20. As indicated by the arrows, the heat bars 36, 38 are urged toward each other to clamp agains~ the blank 22 and thereby form the heat seal closure zone 3~ whereupon they are moved in opposite directions so that the heated plastic cool~ to closure.
The heat bars 36, 38 reach a temperature level sufficient to cause the inner ply 12 to become plastic and create a fu~ion bonding at the zone 34. The temperature and time required to effectiv~ly seal the plastic, such a~ polyethylene, will vary depending upon the thickness of the ~aterial used ~or the inner ply 12 and the total thickness of the outer tube 14.
Next, the bottom of the paper plies of the blank 22 are closed. A standard pinch bottom closure is effected by folding about fold line B-B show~ in Figs. 4 and 5 to create a closure at the lower ~nd of the outer tube 14. The contiguous outer plies 16, 18, 20 are oppo~itely ~tepped at both end3 of the blank 22, as shown in Figs. 1, 3 and 4. Accordingly a pinched clo~ure may be made at both ends of the bag 10. After m~king the clo~ure at ~he 2 ~ llY ~ IJ ~
bottom end, a folded overlapping arrangement is created as shown in Fig. 3. With reference to Figs. 1, 3, 4 and 5 it wlll be seen that the bag is open at the top at 40, and i~ clo~ed at the bot~om end 42. At the open end 40, each ply is stepped up startinq at an outermost front ~4 of the ply 1~ and proceeding to an outermost rear 46 of ply 16, with the exception o~ the inner plaskic ply 12, which is flush cut evenly with ~he innermost non-heat sealable ply 20~ At the closed end 42, shown in Fiys. 1, 3 and 6, the outer contiguous plies 16, 18, 20 are stepped in the exact reverse order as at the open end 40 with the plas~ic ply 12 flush in the same way. Heat reactivatable hot melt adhesive 48, shown by the stippling in Fig. 1, is applied to at least portions of the exposed steps of both the end 40 and the end 42 of the tuhular blank 22.
In the case of the end 42, the pinch closure is made while the hot melt adhesive is still in the molten state and thus the closure is completed in a standard pinch bottom fashion. The inner plastic ply 12, which has been thermally ~ealed at zone 34, is loosely folded at the closed end 42, but not bonded, with th~ outer tube 14. It will there~ore be apparent at the clo~ed end 42 tha~ th~
zone 34 is loosely and freely folded to lie between folded step portions of the outer contiquous plie~ ~8 and 20.
Closing the open end ~0 i8 undertaken when the bag has been filled with a commodity or product 50 to be packaged generally in the same way as the closed end 42. The inner plas~ic ply 12 is fused to closure by the application of heat ad~acent to, but below, the bond 24 across an upper region or zone generally re~erenced at 52 as sho~n in Fig. 6. The heat sealing i5 made by th~ application of hot ~ompression bars 54, 56 ~o the outer side~ o~ the outer tube 14 on opposite sides of the bag 10, similar to the action of the bars 36, 38 illu~trated in Fig. 5. Optionally, the inner ply 12 ~ay ~e, but not need be, severed as ~own in Fig. 7 by the application o~ beveled compreR~ion rollers 58, ~0 on oppo~ite sides of the heat sealed zone 520 The severance would depend upon the needs o~ the packer and also upon the clo~inq equipment used by the packer of the commodity or product 50.

3 ~ ~ 1 Following the heat seallng at 52, ~r at th~ severance therea~
by means of beveled compression rollers 58, 60, the pre-applied hot melt adhesive 48 at the open end 40 ls heated, such a~ by a hot air blast 62, generally at the open end 40 and in the direction of the steps of the outer plies. When melted, the outer contiguous plies ~4 are folded about fold line A-~ shown in ~igs. 6 and 7 for sealing the opposed outer walls by m~ans of passing ~he bag be~ween pressure rollers 64, 66 illustra~ed in Fiq. 9. The sequence for the s~eps explained in conjunction wi~h Figs. 6-9 for the closure of ~he open end 40 are fur~her illustrated in the schematic illus~ration o~ Fig, 10. After the co~modity or product 50 is ~illed to the desired amount within the inner plastic pouch 12, the filled bag lo is placed on an endless conveyer bel~ 68 and carried thereon between the opposing hot compression bars 54, 5~ to cause the inner ply 12 to be heat sealed at the zone 52 at the open bag end 40. The bag 10 is then carried between the optional beveled severing rollers 58, 60 and then passed through the hot air blast 62 to reactivate the hot ~elt adhesive ~8. ~hile the adhesive is în the melted state, the bag 10 is passed through a folding device 70, which may include the pressure rollers 64, 66, as ~hown in Fig.
9. To allow for adhesive set, the bag is then passed betwe~n a pair of pressure belts 72 toward the end of the conveyer belt 68 in fully packagsd ~orm generally denoted at 74.
Thus, after the filled bag 10 illus~rated in Fig. 9 is closed in the manner described ~or clo8ing the open end 40, the packaged content~ 50 will be completely sealed wi~hin the pla tic plie~ 12, which provides an inner sealed pouch closed at both ends ~0 and 42.
At end 42, the heat sealed folded zone 34 may be wholly detached and removed from the outer plies 14 because the fold 34 is not adhered there, but is loosely restrained between the folded plies 16, 18. Hence, when the outer paper plies 16, 18, 20 are ~tripped away as shown in Fig. 13, ~he heat sealed pla~tic pouch 12 is left intact r sealed, clean and ready ~or use of the enclosed protacted commodity or product 50. The loose non-adhe~ive restraint at the zon~ 3g allows for the inner plastic pouch 12 ~o be ~illed wlthout ~) putting undue pressure or ~orce~ on the heat s~aled zone 34 and thus maintains its integrity, prevents bag collapse, and minimize~
pinholing by remaining in the posture shown at Figs. 6 and 7 during ~illing.
As a means for enhancing the removal of the outer tube 14, a pair of slits 76, shown in ~ig. 11, can be made in the outer non-heat sealable ply 20 at the closed end 42. These slits provide for a lif~ing and stripping o~ ~he paper pliPs by simply sliding one's hand between pli~s 20 and 18, at either, or both, of the ~lits 76.
In doing so, one ~here~ore will have gained entry and begun the process of stripping away and removing the outer paper plies, as shown in Figs. 12 and 13.
As an example, the type o~ commodities or products ~hat can be packaged in thQ ~ag lo c~nsist of 25, 50 or loo pound quantities of powdered food items, such as dry milk, eggs, flour, soya meal, or cereals. The bag lO may also be used ~or packaging chemicals and phar~aceuticals due to the effective heat sealed closure o~ the inner plastic pouch and the assurance that the bottom seal integrity has been maintained during filling.
Accordingly, a bag 10 formed in accordance with the invent~on provide~ for the bonding toge~her of con~igu4us laterally o~fset paper plias, and binding the paper plies, or equivalent non-heat sealable ma~erial, together at opposite end~ without attachment batwesn the ends. Then, an inner plastic heat sealable ply i~
bonded at one end only ~o the outer contiguous non-heat sealable plies. The tubular blank, as at ~2 in FigsO 4 and 5, i3 fvrm~d by adhexing each ply to itself along the laterally offset edge~ at 12', 12n; 16', 16n; 18l, 18n; and, 20', 20~ noted above. Th~ hsat sealable ply 12 r~ides within the non-heat ~ealable outer tube 14 and the opposed wall~ of the inner ply are then heat sealed to closure in the zone 34. Next ~he bla~k 22 is subjected to a standard pinch bottom 0108ing procedure freely folding the zone or flap 34 at the ~olded clo~ure end 42 between the adhered plies 16, 18, 20 in a 1008e non-adhesive manner. Th2~e steps ~ay be achieved in con~unction with the utilization of a device as taught in U.S.
Patent No. 2~897,730 to Browning~

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Accordingly, the invention has been de~cribed in conjunc~ion with a preferred embodiment and with means for conductlng the method steps. Howevex, the specification and description are provided in connection with explaining only one embodiment of the invention and it is envisioned that a wide scope of equivalents fall within the claims appended hereto.

Claims (7)

What is Claimed Is:

1. A tubular multiwall bag for the receipt of product therein and being open at one end and closed at the other, the bag comprising:

a plurality of contiguous outer plies of non-heat sealable material;

an inner ply of heat sealable plastic material said plastic material adapted to be heat sealed to closure by heat and pressure applied to the outermost non-heat sealable outer ply;

said outer and inner plies bonded together at said bag open end;

only the non-heat sealable outer plies being bonded together at a pinch closed end at said bag closed end;

said inner plastic material ply being heat sealed to closure across a zone thereof at the closed end and the seal-closed zone being freely folded and non-adhesively held between said outer plies at said pinch-closed end;
and, said inner plastic ply forming a plastic inner pouch substantially equal in length to the contiguous outer plies whereby to reduce the possibility of pouch seal failure during the receipt of product to be filled therein and reducing the possibility of bag collapse prior to closure of the open end upon filling the plastic inner pouch to a desired amount.

2. A multiwall bag of flat tubular form being open at one end and closed at the other, said bag comprising:

a plurality of contiguous outer paper plies;

an inner plastic ply capable of being heat sealed to closure by the application of heat and pressure to the paper ply;

all of said plies being bonded together at the open end of the bag;

only the paper plies being bonded together at the bag closed end;

said inner plastic ply being heat sealed to closure at a bottom zone thereof at the closed end of the bag and said paper plies at the closed end thereof being pinched-closed and having folded therewith said sealed zone of said plastic ply whereby said sealed zone is freely non-adhesively folded at the bag closure;

said inner plastic ply thereby forming a plastic inner pouch;

said plastic inner pouch being substantially equal in length to the outer contiguous paper plies thereby reducing the possibility for pouch seal failure during the filling thereof with a product and the like and reducing the possibility of bag collapse prior to bag closure;

said inner plastic pouch capable of being heat sealed to closure at the bag open and by the application of heat and pressure to the outermost paper ply, whereby said inner plastic pouch may be completely sealed within said outer contiguous paper plies; and, wherein at said bag open and said outer contiguous paper plies being capable of being folded and adhesively secured to close said end.

3. A package having a sealed plastic pouch within a closed paper bag comprising:
a plurality of contiguous outer paper plies;

an inner pouch of heat sealable plastic material having a first heat sealed closure at a first package end;

the paper plies being bonded together at a pinch-closed end at said first package end and having freely folded therebetween the heat sealed closure of said plastic pouch;

said plastic pouch having a second heat sealed closure across a zone thereof adjacent said second package end;

said paper plies further being bonded closed at said second package end;

said plastic pouch being substantially equal in length to the outer paper plies; and a product sealingly contained within said plastic pouch.

4. A method for making from a tubular bag blank of non-heat sealable outer contiguous plies, and an inner tubular plastic ply, a bag having an inner pouch that reduces the possibility of pouch seal failure and bag collapse prior to bag closure upon the pouch being filled with a product; said method comprising the steps of:

applying heat across the bottom of the outer contiguous plies and heating said inner plastic ply;

applying pressure at said bottom of the outer contiguous plies to heat seal said inner plastic ply across a bottom sealed zone thereof;

adhesively ending all of said plies together at the top end thereof, said top end being an open end;

bonding only the outer contiguous plies together at the bottom end of said bag; and, pinch-closing said outer contiguous plies at said bottom end and non-adhesively freely folding therebetween said sealed zone of the inner plastic ply, thereby forming an inner plastic pouch for the receipt of product therein through said upper open end.

5. A method for filling and sealing a multiwall bag having an inner plastic pouch, and outer contiguous non heat sealable plies, said inner plastic pouch and outer plies being bonded together at an open top end, only the outer plies bonded together at an opposite pinch closed end, the pouch having a heat sealed closed bottom end and the sealed bottom end being freely folded within the pinch closed end of the outer plies, comprising the steps of:

filling said plastic pouch through said open end with a product;

restraining said pouch heat sealed and folded closed bottom end at said pinch closed end of the outer plies;

maintaining the height of the pouch to be substantially the same as said outer plies during filling thereof;

applying heat across the top end of the outer contiguous plies and thereby heating said inner plastic pouch across a top zone thereof;

applying pressure to the non-heat sealable plies at said top zone and thereby heat sealing and fully closing said inner plastic pouch thereat; and, bonding said outer contiguous plies together at said top end and thereby closing said outer contiguous plies to form an outer bag enclosing said filled inner plastic pouch.

6. The method according to claim 5 including severing said top heat sealed zone of the inner plastic ply.

7. A method for making a sealable multiwall bag having an inner plastic pouch and non-heat sealable outer contiguous plies from a tubular blank comprising an inner plastic ply overlaid by a plurality of outer contiguous plies made of paper, comprising the steps of:

applying heat across the bottom of the bag blank to the paper plies and heating said inner plastic ply;

applying pressure at said blank bottom to seal said inner plastic ply across a bottom sealed zone thereof;

adhesively bonding all of said paper plies together at the opposite end of the blank, said opposite end being an open end;

bonding only the paper plies together at the bottom end of said bag blank;

pinch-closing said paper plies at said bottom end and non-adhesively freely folding said sealed zone of the inner plastic ply between said paper plies, thereby forming an inner plastic commodity-receivable pouch for the receipt of commodities therein through said open end;

filling said plastic pouch with a commodity or the like to a desired amount;

applying heat across the paper plies at the opposite open end and thereby heating said inner plastic ply across a top zone thereof;

applying pressure to the paper plies at said top zone and thereby heat sealing said inner plastic ply thereat;
and, bonding the paper plies together at said open end and closing said paper plies to form a bag containing said inner plastic ply in the form of a sealed pouch.