CA1196848A

CA1196848A - Method and apparatus for high speed pouch and bag making

Info

Publication number: CA1196848A
Application number: CA000406378A
Authority: CA
Inventors: James R. Wood
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-06-30
Filing date: 1982-06-30
Publication date: 1985-11-19

Abstract

ABSTRACT OF THE DISCLOSURE
A method and apparatus for high speed pouch or bag making from thin, heat-sensitive thermoplastic film webs or multi-ply webs of paper, film and foil in which the seal pattern may be simple or complex sealing and in which the method is applied to a continuously moving web and sealing is achieved at temperatures below the softening temperatures of the film or the sealing interfaces. A method of forming an open pouch comprising the steps of continuously pulling an elongated web of pouch forming material at a constant speed along a pouch making path which extends continuously through a web coating station, a web collating station, an electron beam curing station and a web cutting station. A pattern of a coating is applied to a first surface of a first continuous web of pouch forming material as it is pulled continuously through the web coating station to render the interface bondable at a seal line and non-bondable in the area of the storage compartment when subjected to electron beam radiation. A second web is directed into a face-to-face relationship with the first web in the collating station and irradiated with E.B. radiation to bond, without heat distortion, the bondable areas of the web at the interface while leaving the non-bondable areas free from securement and the pouches are cut from the webs by severing along transverse cut lines.

1.1

Description

This invention relates to a high speed method and apparatus for making pouches, bags and the like.
Pr~sently in the packaging industry, pouches and bags are made on convent.ional machines by heat sealing side seams ; and bottom seams or glue sealing these seams. In the heat sealing machines which are presently in wide use, electrically heated heater bars s'naped to the pattern of the seal to be made are pressed into physical contact against the webs which are to be sealed with an output limiting dwell t;.me being required for the conduction o-f heat through the webs to their sealing interface to effect a seal.
In the glue sealing machines which are widely used in industry and which are manufactured by a large number of different machine makers, glues suitable for paper or film or foil are applied i.n patterns for the side seams and bottom closure.
Outputs are lim.ited hy the mechanical applicator's aximum frequency and the "green-tack" time for the glue to "bite" and hold the glued interfaces together before the bags are delivered from the bag machine and pressure packed in bundles allow.ing the glue to 51Owly lose its solvent or aqueous components and permanently set.
The average output in bags per minute ranges from 60 to 200 per minute in the case of the heat seal machines and from 100 to 1000 per minute in the glue seal machines. The norms are ` 125 and 200 per minute, respectively. All of ~hese machines require mechanical set-up for change of bag size with various ; change of size parts. With some square bottom bag machines, a series of machine sizes are made to cover the range of bag sizes :
. 30 due to the mechanical complexity of parts and adjustments being too great to be accommodated in one machine.
.", In the heat seal machines thermoplastic webs such as polyethylene film present limitations in the type o con-struction for the pouch or bag due to the heat wea~ening of the web by a 1/8' to 1/2" wide seal across the web at right angles to web motion. This allows only "side-weld" bags to be made or necessitates web transport means to support the "j~lly-like"
condition of the transverse seal area un~il it cools and re-covers sufficient tensile strength to resist the normal machine operating we~ tension.
The majority of bags and pouches printed today such as cookie bags, dog food bags, cake mix and crystal pouches, etc., etc. have high quality graphics usually in rotogravure printing. This necessitates the pouch and bag making to be separate operation, as the old "print-and-make" bag making c) ~ , 0 ~ ~5 r~*~n~ are in the relatively lower quality flexographic printing and the average web speed in bag making is in the order of 100 to 200 feet per minute vs 600 to 1000 feet per minute in a rotogravure press. Also, rotogravure press widths usually allow the pouch or bag web to be printed two, three, four or more wide and slit into single roll widths for the pouch or bag machine. This .increases the printing output six to ten times that of the "print.-and-malce" bag method, provides superior quality half tone printing and the viable economics of one $2,000,000 rotogravure press output matching the total output . of three or four $300,000 pouch or bag machines. The first printed bags, where the printing was held in register on the bag or to the bag machine cut-off, were by necessity produced with a tail end printer in line with the bag machine (print~and-make method) and driven by a "one-time-side-drive-shaft" from .

~ - 2 -~' the bag machine i.e. one revolution of the printing cylinder or printing impression per one cut-off of the bag machine.
The printed repeat or impression length was pre-sPlected to exactly match the bag machine cut-off len~th and register variations caused by web tension changes were manually controlled by the operator adjusting a compensating web roll situated between the tail end printer and the bag machine which would lengthen or shorten the web pati between the printer and bag machine causing the print to arrive at the cut-off knife later or sooner respectively and thus move down or up to register in in the bag face. This method is slow and waste is high both related to the skill of the operator in watching the printed web and making the correct compensator roll adjustment at the right moment and in the right amount.
~ great improveme~t occurred in the 1930's with the development of electronic register control for bag machines allowing the compensator roll to be automatically adjusted, or the bag machine pull rolls thru a differential drive to be automatically slowed down or speeded up while in continuous ~0 motion. This development also allowed preprinted off line webs to be made into pouches and bags keeping the printing in register to the pouch or bag face. The control being photo cell activated by a web "lay-mark" usually a small black rec-tangle about l/8" wide in machine direction by l/2" long across machine direction which was pre-printed on the web, usually at the edge of the web or in the area of the bottom closure folds to be hidden from sight in the final bag, in an off line printing operation. This development improved the printing quality on bags, reduced waste and allowed printed bags to be made at increased speeds previously limited by operator skill and human error. However, ~he pouch and bag machine '~
speeds are still limited by the inherent frequency limitationsof mechanical moving parts, particularly opening and closing mechanisms for the application of adhesive gluPs or heater jaw actuation in specific patterns and areas for thermo-sealed seams and closures. The majority of heat seal pouch and bag machines have time consuming intermittent web motion or a series of mechanical heat sealing stations to provide d~ell time in th~
order of 0.50 second to allow heat transfer from the hiyh tem-perature sealer bar surface thru the web to the sealing interface.
Also, considerable bag machine down time, skilled labour and waste is encountered at each "set up" of a glue or heat seal machine for a pouch or bag of different size to be made within the limited size range of each machine. Also, expensive change ; of size parts are often required for each size the machine is ' ~; to produce. With the steadily rising costs of new and physi-.":
cally improved pouch and bag materials in papers, fi~ms~and foils, increasing labour rates and capital cost of pouch and bag machines the packaging industry in this area is operating at ' 1950 outputs, unit costs and qualities in the 1980 efficiency and higher ~uality demanding market place.
The use of adhesives to overcome the above limitations oE heat sealing in the manufacture of pouches or bags from single . .
wall heat sensitive thin thermoplastic films or substrates with the ~hermoplastic coatings is counter productive as ths barrier ~ quaiities of the films or coatings prevent the rapid escape of ;~ the solvent or aqueous components of the adhesives necessary to ..:
eEfect a high speed strong seal. This inve~tion of high speed r~ pouch and bag making overcomes these current limitations in the present state of the art of pouch and bag making by providing ~he method and appara~us to make high speed (in the order of 0.03 , second) strong seals on pouches or bags of single wall tnin gage ,., ., ':',, heat sensitive plastic -Eilms or substrates with moisture or solvent barrier laminations or coatings by the combination of 100% reactive adhesive, electron beam radiation and the lack of both heat and speed limiting mechanical apparatus.
To significantly increase the lineal web speed and output of pouches and bags and to approach zero defect ~uality control, I
propose to use Electron Beam radiation for sealing webs to form pouches at extremely high speed. In particular, this use of Electron Beam radiation allows radical pouch and bag machine redesign eliminating the various reciprocating speed limiting devices and time consuming heat transfer and other sealing functions inherent in pouch and bag making machines in the present art of two operations oE pre-printing and pouch or bag making. The pouch and bag machine per se has been eliminated and only its free flowing web folding and tube forming functions retained and combined into a novel high speed single line pouch and bag making machine consisting of an unwind web tension control unit rotogravure printing 8~R~

,~,7 e o f' ~-c~ D/ e~
units ~ E.B. curable adhesive, web folding and or tube forming, E.B. radiating " slitting and rotary cut-off.
My new high speed pouch and bag ~aXing machine can achieve lineal weh speeds up to and beyond 300 feet per minute with output rates of 5,000 pouches per minute and higher including simultaneous multi-colour rotogravu~e printing. Near zero defect quality seal control is attained with the mQcron thickness laydown control of the electron beam curable adhesive by the rotogravure process in I conjlmction with the Electrocurtain (Trade r~ark of Energy Sciences 1 10 Inc., Woburn Mass., U.S.A.) Processor Contro] of the Electron Beam radiation exposure and penetration. The radiation can be preset on the Processor control panel and through a slave control of the grid drive ~he Processor output tracks the web thruput so the fixed preset megarad exposure level is delivered regardless of the web speed.
This simplifies stilrt up and shut down problems, prevents web burn out, reduces waste and autcmatically maintains excellent quality control of pouch and bag seals. The high velocity of the E. B.
:i .
ctrons, near to hhe speed of light, and their high energy of 100,000 electron volts frcm the two lnch wide (machine direction) I 20 Electrcc~Lrtain, effect a chain reaction polymeriza-tion cure that is practically instantaneous in the E.B. curable adhesive. The electron beam radiation will penetrate opaque papers, metal al ~inium foil and opaque films to instantly cure huried E. B. curable adhesive several plies below the incident surface as is necessary in th;s invention in the multi-Layer folded S.O.S. bag bottom closures all sealed simultaneously and in the final folded flat attitude. No other known technology Ultra Viole~ Infrared, Ionization, etc. can deliver the ;,' ..... ~
.

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.
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30,000 fold greater energy of E.s. (UV = 3 electr~n volts versus E.B. = 100,000 electron volts) nor penetrate dense opaque packaging materials as are us~d in the pouch and bag constructions for t~da~'s market. Also, W and IR in~xIrt relatively high heat to the materials they radiate whereas EB is a cool process. E.B. curable adhesives require 10 electron volts to "knock out" one elect~on in the E.B.
adhesive essential to start the chain reaction of high sp~ed E.B.
curing. Bond strengths of E.B. curable seals are of sufficient strength to be destructive under test to the films or saran coatings on the films or paper substrates. m ese 100~ reactive adhesives are made by Mobile Chemical Co., Polymer Industries and others.
Further benefits of this novel high speed pouch and bag making method:
(a) the abilit~ to make transverse or across machine direc-tion wide seal patterns on light ~gage .OOl~and upwards heat sensitive polyethylene webs without heat weakening the seal area to a "jelly-like" consistency and without restricting the poly bag or pouch construct-ion to a "side weld" seal combination narrow seal and cut-off and without a oomplex web transport m~chani~m to carry the heat sealed poly web until it cools and regains sufficient tensile strength to resist normal machine web tensions. This is due to the E.B. curing t~king place at a ten~x~rat.ure below the softening point of extensible webs such as polyethylene, (b) the E.B cured seals do not require a `~ special oxygen free curing environment as all the seals :
'''' 3L~8~1~
where air is aut~matically excludecl. Also, the E. B.
curable adhesive is applied to one surface of a ~eb ~efore folding upon itself or ccming in c~ntact wqth a seconcl web and the fluid state of the uncured adhesive pattern allows movement of one web relative to the other tD avoid tension or guiclance wrinkles and the lack of heat in the instant E.B. cure precludes the forming of heat or shrink~ge wrinkles and obviates the ne oe ssity of c~oling jaws or rolls as in most conventional heat seal pouch and bag machines, - (c) the rapid rate of the chain reaction poly-merization or cure prevents weak pouch or bagseals on pcrous paper substrates by effecting the cure instantly and before a significant percentage of the adhesive is absor~ed into the substrate and weakening the interface seal.
(d) EN~RGY CONSE~V~TION - In this method of high speed pouch and bag making multiple seals at different ply levels can be made simNltaneously with a single EB
exposure as opposed to conventional pouch and bag machines using conduction heated high temperature heater bars in a series of heat sealing stations. These heat sealing heater bars have a high heat loss whereas approx. 90% of the EB
radiation enters the product. m e energy saving is greater when EB seals are compared to conventional pouch and bag mach.Lne heat seals on solvent or water based adhesives applied inline or offl.ine which adhesi.ves must pass thru a thenmal dryer to rernove the solvent or water prior to heat sealing wi.th a hot sealer bar. If 100~ solids therm~seal adhesives are applied inline or offline for subsequent conduction heat sealing high energy input with ~lherent high heat loss are incurred in melting ~he adhesive, heat ng the applicator rolls and adhesive pan etc. Typical energy values - thermal d~y/cure latex are 2745 BTU per pound -elec~ron c~lre 100~ reactive adhesive are 2 megarads or 10 BTU per pound.
(e) NCN POLLUTING: Chemical and thermal - the noxious polyethylene vapors emitted by a polyethylene side-weld bag machine c~re well kncwn to those familar with the present state of the art. In this high speed pouch and bag ma]cing method the EB seals are made well below the vapollr generating temperatures. The EB 100% reactive adhesives are solvent free and therefore do not emit hydro carbons to the atmosphere as solvent base and 100%
, . .
hot melt adhesives emit in thermal drying and hot melt application.;

SUMMARY QF INVENTION

According to one asl~ect of the present invention, a method `:
of formlng an open pouch having an article storage compartment formed between two panels which are secured to one c~nother along a seal line w~lich extends about the periphery of the article storage ccnpartm nt ~ and which is open along an opening line extending transversely between `~ opposite ends of the seal line, comprising the steps of; continuously ` ~ ~ a first elongated web of pouch fonning material at a constant speed along a pouch making path which extends continuously through a web coating station, a web collating station, an E.B. curing station and a web cutting station, applying a pattern of a coating to a first surface of said first continuous web of pouch fonning material, as . . . =
~, ` 30 _______________ _ 7 a -c~, ~ "
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it is~ d~e~ continuously through said web coating station,to render the interace bondable at said seal line and - non-bondable in the area of said storage compartment when subjected to electron beam radiation, direrting a second web of pouch forming material in a face-to-face relation-ship with said first web after passage of the first web through the web coating station to form said interface therebetween in said collating station, continuously J ~-~v}~g the first and second webs through said E.B. curing station and irradiating the entire interface of said webs with a beam of electron radiation emitted from an electron beam generating device to thereby bond the bondable areas of the webs at the interface while leaving the non-bondable areas free from securement and cutting the pouch from the webs along a line disposed outwardly from the inner edge of the seal line and along said opening line to form an /cOC
open pouch as the bonded webs are ~r~en through said cutting station.
The invention will be more clearly understood after reference to the following detailed specification read in conjunction with the drawings wherein Fig. 1 is a pictorial view of a typical pouch which may be manufactured by the method of the present invention;
Fig. 2 is a diagrammatic illustration of a number of alternative methods of coating a pair of webs for producing a pouch according to Fig. l;
Fig. 3 is a pictorial view of ~ alternative form of seal line which may be employed in the manufacture of a ;` pouch;
Fig. 4 is a diagral~matic side view of a pouch ma~ing rnachine in line with a high speed printing rnachine suitable for use in manufacturing bays acoording to the rnethcd of the present invention;
Fig. 5 is a diagra~matic representation of a section through a nulti-layer web illustrating the location of differ~nt seal lines;
Fig. 6 is a pictorial view o a web passing ,hrough a roto-gravure device illustrating a ~æb pattern suitable for forming a square bottom bag;
Fig. 7 diagrammatically illustrates the manner in which the web of Fig. 6 is folded to form a tubular sleeve;
Fig. 7a diagramatically illustrates the rnanner in which a web is folded and coated when the bags are to be formed by transverse cut-ting o the coated web;
Fig. 8 diagrammatically illustrates the position of the various layersof the web of Fig. 7 when subjected t~ E.B. radiation;
Fig. 9 is pictorial view illustrating a square bottom bag constructed from the web of Fig~ 6;
Fig. 9a is an enlarged detail view illustrating the con-struction of one corner of the square bottom bag of Fig. 9;
Fig. 10 is a plan view of a coated web showing a coating pattern suitable for forming a satchel type square bot-tom bay;
Fig. lOa shows a first fold along a central gusset fold line, and Fig. lOb shcws a second fold in which the central gusset fold line is folded inwardly; and Fig. 11 is a pictorial view of the bag formed from the web of Figs. 10, lOa and lOb.

_ g_ :`

With reference to ~he drawings, the reference numeral 10 refers generally to a pouch which consists of a first panel 12 and a second panel 14 arranged in a face-to-fa oe relationship and bonded t~
one another at an interface thereof along seal lines 16a, 16b and 16c.
me seal lines 16a, 16b and 16c represents the bonded areas of the two panels an~ are hereinafter collectively identified by the refer o-e nuner~l 16. ~e _ /

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unbonded area located within the bonded areas 16 serves to form an article :receiving pouch 18.
It will be understood $hat the pouch may be in a form of a plastic bag or any other article receiving container and, as will be described hereinafter, the sealing method of the present invention may be used to secure webs at localized areas for the production of a wide range of items not necessarily in the form of pouches or containers.
~ ith reference to Fig. 2 of the drawings, it will be seen that a first web 22 and a second web 24 are guided into a face-to-face overlying relationship with respect to one another between a pair of rollers 26 and 28.
The webs 22 and 24 may be made from a material which is bondable when suhjected to electron radiation-or-from material which is non-bondable when subjected to electron radiation. In either case, a coating is applied to at least one surface of one web so that the bonding characteris~ics of the coated area of the web are opposite to those of the non-coated area. The coating may serve to make the coated area bondable or it may serve as a screen or resist coating to m~ke an otherwise bondable material non-bondable.
Examples of a suitable non-bvndable ~eb are paper, aluminum foil and cellophane. Examples of a suitable bondable material available in web form are polyethylene, poly-propylene and nylon, all of which are capable of forming a fusion bond but which are more efficiently bondable using E.B. curable ~dhesive. E.B. curable adhesives and coatings, suitable for forming a bond are available from a number of suppliers such as rlobile Chemical Co., Polymer Industries, American Cyanamid Company, Dow Corning Corporation and .
;

CelaneceChemical Company. Relatively recent developm~nts have produced 100%
reactive adhesives and o~atings of various moncmPIs an~ oligo~ers designed for viscosit;es (helow 100 centipoise~ suitable for rotogravure application and poly~,erization or curing by electron beam radiation. A variety of suitable E~B curable adhesives are knc~n to those skilled in the art. Coat-ing materials suitable for E.B. radiation screening purposes are metallic or high density coatings having substantial resistance to E.B. transmission, and may be applied by rotogravure process to produ oe variations in pouch and bag making fusion seals.
With reference to Fig, 2 of the drawings, three alternative methods of coating are illustrated at areas A, B and C, respectively. In area A the coating 30 is a coating of bondable material; in area s the coating 32 lS a coating of non-bondable material, and in area C the coat-ing 32 is agaln a coating of non-bondable material. The coating in area A
and area B are applied by either of the rotogravure printing cylinders 34 and 35 (Fig. 4) and the coating in area C is applied by a rotogravure print-ing cylinder 36 (Fig. 4). The coating applied in Area A is applied to a f~rst surface 38 of the first web 22 which is located at the in-terface between webs 22 ancl 24 when the webs are brought -together bet~een rollers 26 and 28. The coating at area B is applied to a lower surface 3g oE web 24 which is again located at the interface of web 22 and 24 when -the webs are brought together. The coating 32 applied in area C is applied to an upper surface 40 of web 24.
When a bondable coating is applied as indicated in area A, it is applied t~ cm interface surface in a pattern corresponding to the seal line 16a, 16b and 16c. Thi.s pattern is applied by the rotocJra ~ p~t~n~ e ~th ~,~ .
~: . ~
`'.' ''.', ''; - 11 -'..

.1.19ti~ ~8 a plurality of printed areas arranged side by side and closely following one another on ~he surf~ce 38. The web 22 with the pattern of area A applied thereto at longit~ldinal intervals along the length thereof is located in a face to-face relationship with the web 24 between the rollers 26 and 28. It will be noted that it is only necessary to apply a pattern as E.B. curable material to one of the webs so that there is no difficulty in aligning the webs 22 and 24. ~he webs then pass through a radiation curing device 42 which ; 10 activates the bondable coating 30 to form a bond at the coated interface. The web is then slit longitudinally along slit lines 44 and cut off along transverse lines 46 to sever the individual pouches 10 from the continuous we~.
When the webs are made from bondable material and the coating is a screening material as illustrated in section B, the coating is again applied by the rotogravure cylinders 34 or 36 and the webs 22 and 24 are located in a face-~o-face relationship between rollers 26 and 28 and the composite web ist~i~e~ through the radiation curtain generated by the electron beam generating device 42. Xn this instance, the coating 32 screens the areas of the interface to which it is applied so that ~usion bonding can only occur at the unscreened portions of the interface.
~ screen coating may be applied by the rotogravure 36 to the upper surface of the upper web 24 in order ~o prevent bonding of otherwise bonda~le webs as pre~iously described. I~hen the rotogravure cylinder 36 (Fig. 4) is used, it is not necessary to use the rotogravure cylinder 34 and it is not necessary to apply any coating to the interface. This method results in a pouch or bag ~ith no , ~ - 12 -'' ' coating or adhesive on the pouch or bag interior surfaces which coatings or adnesives or their components can contact or migrate into the subsequent pouch or bag contents when the contents are degradeable by the coating or adhesive or components thereof. It will, of course, be understood that when the rotogravure cylinder 34 is used to apply a coating to the interface, it is not necessary to apply a coating to the upper face of web 24. When the coating is applied to the upper face of the web 24, as snown at C in Fig. 2, it may be applied after the webs 22 and 24 are located in a face-to-face relationship. It t~ill, however, be understood that the coating may be also applied before the webs are located in a face-to-face relationship. The coating serves to screen or mask the otherwise bondable areas o the webs at the sealing interface as the we~ moves through the radiation curtain so that bonding occurs only at tne unscreened interface and the pouch is made with no coating or adhesive on either of the pouch interior surfaces ad~acent to the contents of the pouch. Again, the web may be slit and cut off as previously described.
Several forms of a suitable apparatus for ~igh speed pouch and bag ~ikins are illustrated in Figr 4 of the drawings. A
si~ple ~Quch machine is illustrated in area D of Fig. 4 and ~ multi-colour printing machine is illustrated at area E in line ~lith the high speed pouch and bag making machine.
With reference to Fig. 4, the reference numeral 50 refers generally to a high speed pouch and bag making machine according to one embodiment of the present invention and the reference numeral 52 refers generally to a multi-colour printing machine.

11~16~

The high speed pouch and bag making machine includes a first unwinding reel 54 and a second unwinding reel 56.
The web 22 is unwound from a roll of material supported ` on the first unwinding reel 54 and the web 24 is unwound from the roll of web material supported on the second .:
unwinding reel 56. A pair of pull rollers 58 pull the web 22 off reel 54 and a pair of pull rollers 60 pull the web 24 off reel 56. A rotogravure cylinder 34 of a rotogravure printing device 62 applies a~ adhesive of the -type previously described, as being applied to area A of the web 22 (Fig. 2).
The webs 22 and 24 are brought together at rollers 26 and 28 with the adhesive applied to the interface. The webs 22 and 24 pass through an electron beam radiation device 42 in which a bond is formed at the interface as previously described.`
The bonded webs are then longitudinally slit by slitting cu e~s 64 and transversely cut off by rotary knife 66. The individual products are then stac~ed by means of a stacker mechanism generally identified by the reference numeral 68.
As previously indicated, the high speed of operation of the Electrocurtain tTrade ~lark) electron beam radiation device is compatible with the speed o operation of a multi-' colour printing press. Consequently, a multi-colour printing press nay be arranged in line with the high speed pouch and bag machine previously described, in which case the weD 24 is unwound from a reel 70 through any required number of printing press colour units 72 before being directed to the rotogravure cylinder 35 or 36 (Fig. ~) depending upon whether the coating is to be an ~.B. curable adhesive or a resist coating.
When the process of the present invention is to be -- lg --.
., 8~8 co~bined with a multi-colour printiny operation, it is desirable to apply the E.B. curable adhesive or the resist coating to the s~e web to which the printing is applied so that accurate registration of the printed material and the coating may be achieved with ease. In Fig. 4 of the drawings, two robogravure pr m ting units 35 and 36 are prcvided for use in applying the coating of the present invention. When the coating is to ~e applied to a surface, of a printed web, which will ultimately be located at the interface, it is applied by the rotogravure cylinder 35. When the coating is to be applied to a surfaoe of a printed web, which will ultimately form an upper surface of the webs when they are brought together, it is applied by the rotogravure cylinder 36.
me rotogravure printing unit 35 comple-te with a dryer may be used to apply a resist coating or an EB curable adhesive, the dryer being necessary only for the resist coating. The rotogravure printing unit 36 complete with a dryer is required only when a resis-t coating is required on an outside face of a printed or plain (unprinted) pouch or bag. Should the resist coating interfere with the printing then the standard reverse mc~e of the printing press color units is employed via web path 72R and the resis-t coa-ting applied to web 22 from unwind 56 via web path 22B and the resist coating on web 22 is adjacent to the incident EB radiation when webs 22 and 24 are extended fram rollers 26 and 28. When the rotogravure cylinder 35 isused to apply a coating to a face which will ultimately ke located at the inter-face, unwind 56 supplies web 22 which is extended into con-tact with the coat~d side oE web 2~ via web path 22a prior to the coa~ed side oE web 2~ contac-t-ing web rolls cmd to ensure that the coated face is located at:the~ inter-face when t~e webs 22 and 24 are directed to-the rollers 26 and 28.
From ~le foregoing it will be apparent tha-t the present invention provides a simple and efficient method of high speed pouch ~nd bag making which is readily applicable to the manufacture of products made frcm roll stock and secured along spaced seam lines. The m~thod and apparatus is capable of opera-ting at high speeds co~parable to -t~ose of colou~ pri~ting p~èss units so that .
the a~aratus m~ay be ::
,.

located in line with a multi-colour printing press~
A rotogravure printing device is particularly suitable for use in applying the coating to the in~erface. As is common practice with a rotogravure printing device, the lay down weight of ~he coating may be determined by the control-led micron engraving depth of the printing roller and as applied to the coating of a bondable material in the present invention, the lay dOt~ll weight may be such that the bond which is achieved is permanent or peelable. In addition, local areas of the lay down pattern can be of a different lay down weight to that o other areas so that the bond may be permanent in such areas and peelable in other areas, a peelable bond being provided in areas where easy opening of a package may be required with a permanent bond being provided in other areas where a peelable bond must be avoided.
As diagrammatically illustrated in Fig. 5 of the drawings, the composite web which is directed through the E.r.. radiation device 42 may consist of layers ~0, 82, ~4 and 86 havir,g interfaces 88, 90 and 92. E.~. radiation curable coatings 88a, 90a and 92a may be applied to the interfaces S8, 90 and 92 respectively, so that the coated portions of the various interfaces are simultaneously bonded on passage through the E.B. radiation device, while the uncoated portions xemain unbonded thus, it will be seen that the present invention provides a method whereby selective interface sealing of a multiple stack of interfaces may be achieved.
It will be noted in some instances, the coated areas of one layer overlap the coated areas of another layer, this, hot~ever, does not prevent the bonding of the interfaces at both levels.

. .

~ ~C~8~

A practical exa~ple of selective interface coating of a multi-layer web is described hereinafter as applied to the high speed manufacture of a square bottom bag.
With reference to Fig. 6 of the drawings, the reference numeral 100 refers generally to a web of material suitable for use in the manufacture of bags such as coffee bags, air sickness bags and the like. The web may be a web of paper or plastic material or the like. The web is directed throuyh a rotogravure printing device 102 and a coating of ~.B. curable adhesive is applied by rotogravure : cylinder 104. For the purposes of describing the pattern in which the E.B. curable coating is applied, the gusset fold lines alon~ which the web 100 is subsequently folded are illustrated in bro~en lines. The qusset fold lines include central gusset fold lines 106 bounded on either side by outer gusset fold lines 108. The E.B. curable coating is applied to a marginal edge portion 110 which extends continuously along one free edge of the web 100 as will be described hereinafter the coating which is applied to the marginal edge portion 110 is subsequently used to pro~ide a longitudinal seal when the web is folded upon itself to form a tubular sleeve.
The bottom wall portion of eacll bag which is to be formed from the web is a portion located between the bro~en lines 112 and 114 which extend transversely of the web 1~0 ; The rotogravure cylinder 104 applies an E.B. curable adhesive to the portion 116. It will be noted that the E.B. curable portion includes a narrow band extending across the width of the bottom wall former po:rtion in the area of the lower edge 112 and triangular shaped portions 118 projecting :, , .

upwardly therefrom to the intersection of the gusset fold lines 108 and the bottom fold line 114. It will be noted that an uncoated triangular shaped portion 120 projects downwardly between the triangular portions 118.
Figure 7 of the drawings shows the wPb of Fig~ 6 in a partially folded configuration. It will be noted that the central gusset fold line 106 is disposed inwardly from the gusset fold lines 108~ The manner in which the multiple interfaces are formed will be apparent with reference to Fig. 7 of the drawings which also illustrates the location of the various coated portions at preliminary folding. The folding of the web is completed in the relationship indicated in Fig. 7 until the oppositely disposed faces are in intimate contact with one another whereupon the web is directed through an E.B. radiation device as illustrated in Fig.8 of the drawings. The E.B. radiation device causes curing of the E.B. curable material as the web passes therethrough so that a permanent bond is formed at each of the E.B. curable coated interfaces while the uncoated interfaces remain unbonded.
After E.B. radiation the individual bags are cut from the continuous web by severing along the line spaced below the level of the transverse coating 112 so that the bag is preferable cut along an unsealed area so that in forming the transverse cut, the open end of the bag is formed. Referring bac~ to Fig. 7 of the drawings, it will be noted that the uncoated triangular areas 120 are located between the coated areas 118. ~s previously indicated with reference to Fig. 5 of ~le drawings, E.B. radiation of this structure will provide a bond at the coated areas while 6~

leaving the uncoated areas unbonded. The unbonded triangular portions 120 are important when it comes to the erection of the bag to form a s~uare bottom. The unbonded portions 120 in combination with the bonded portions 118 cause the bottom wall forming portions of the bag to articulate along the boundary lines 124 and tranCverse hinge line 114 to form a square bottom bag.
Fig. 9a shows an interim stage in the erection of a bag in which it will be seen that the outer gusset fold lines 108 extend across the bottom of the bag and the coated portions 118 on either side thereof are bonded together to form a double thickness. The uncoated triangular area 120 being free from attachment with respect to the remainder of the bottom wall so as to permit articulation of the various panels to the required square bottom configuration.
~` Various other printing devices may be used for ; applying the required coating to the web. For example, the coatlng may be applied by flexographic or etter press printing systems with various degrees of efficiency.
~s previously indicated while the present invention is particularly suitable for use in the high speed manufacture of ~ouches or bags or tlle like, the method and apparatus may be used for the manufacture of any number of pattern bonded structures. For example, in Fig. 3 of the drawings, a ~inted coating is applied in the form of,-~a pattern 90 to one transparent ~eb so that after radiation bonding the coated area is bonded wllile the adjacent areas of the web are unbonded. As a result the bonded areas become clearly visible. Tne pattern 90 may be in the form of a date code trade mark or advertising material. ~ihen a pouch or the ~, .

.

li~e is to be manufactured as described in Figs. 1 and 2, the pattern 90 may be in the fo~n of a continuous script extending around the area which will form the seal lines 16a, 16b and 16c of the pouch of Fig. 1, Thus it will be seen that in the forming of a seal line, the pattern established by the pattern bonding may itself be used to convey a message relating to the package or its contents.
Fig. 7a illustrates the manner in which a satchel type square bottom bag can be made by the application of an E.~. bondable coating to selected portions thereof.-In this embodiment a web is folded along longitudinalextending fold lines 113 and 115 in order to form an inwardly directed gusset. By the application of a bondable coating in the manner previously described an E.B. bondable coating is applied to the areas 117 and to triangular shaped areas 119 and circular areas 123 at corner 121. It will be noted that in the corner 121, the bondable coating is applied to each of circular areas 123 while in ~le coated area 119 the bondable coating is applied to the triangular corner section with circular areas 121a being free of bondable coating. It will be under-stood that a pattern of E.B. hondable material will be applied at each corner forming portion of the web. Thus, when the web is folded to locate the inner faces in a face-to-face relation-ship and the web is passed through the E.B. radiation device, a bond is formed about the periphery of the bag forming portion of the web and thereafter the web is severed along the line 125 to separate one bag from the web. It will be noted that the uncoated areas 121a will be located directly opposite the coated areas 123 when the web is folded to a lay-flat con-figuration prior to E.B. radiation. Similarly it will be noted ~.~9~

that the uncoated area at corner 121 will be located directly opposite the coated area 119. Thus, the radiation is able to pass substantially unrestricted through the uncoated areas to the underlying coated areas so that a bond of substantially the same strength may be formed at the coated areas of each interface without requiring any substantially greater power than that required to form the required bond at one inter-face. In this embodiment, the uncoated areas serve to permit the substantially free passage of the E.B. radiation there-through. Thus, it will be seen that the method of patternbonding may be such as to provide a discontinuous coating at one interface so that the radiation may pass therethrough to Eorm a bond at an underlying coated interface.
Figs. 10, lOa and lOb illustrate a further pattern suitable for use in the manufacture of a satchell type square bottom bag. In this embodiment, the bondable coating is applied in the manner previously described to a web 200 along trans-versely extending longitudinally spaced areas 202. Each area 202 consists of a longitudinal seam forming portion 204 and a pair of generally diamond shaped corner portions 206. The diamond shaped portions 206 are centered on fold lines 213 and meet one another at the gusset fol.d line 215. As shown in Fig. 10, the web 200 is initially folded along the gusset fold line 215 and as shown in Fig. lOb the web is subsequently folded along the fold lines 213 to locate the gusset fold line 215 inwardly thereof. The web is irradiated when in the folded position shown in Fig. lOb to bond the bondable areas and the ;` web is cut along the transverse cut line 216 which extends centrally of the width of the coated areas 202. The bag formed by this method is illustrated in Fig. 11 of the drawings.

A pouch, such as a retort pouch, may be made by the method of the present inventio~ in which one or more of the webs is formed from a laminate consisting of Mylar (trade mark) aluminu~ foil and polypropylene.
Various modifications of the present invention will be apparent to those skilled in the art. For example, it ~` will be apparent that the method of the present invention ` permits the production of a pouch from webs which are in the form of laminates in which one or more of the webs consists of a laminate of a heat sealable plastic material and an aluminum foil or a heat sealable plastic material and paper or the like.
It will also be apparent that the method of the present inven-tion permits a seal to be formed between the bondable webs at temperatures below the heat sealing tempertature of the thermoplastic film used to form one or other of the webs.
The method o the present inv~ntion also permits the produc-tion of a pouch in which the seal areas which are coated with - bondable material constitute up to 50~ of the total pouch face area. Preferably, each web from which the pouch is made has a thickness which does not exceed 0.008".

,, ~`~

~ 30 ., .

~ -22-.,

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are as follows:

1. A method of making an open pouch having an article storage compartment formed between two panels which are secured to one another along a wide, typically 1/2" seal area which extends about the periphery of the article storage compartment and which is open along an opening line extending transversely between opposite ends of the wide seal area comprising the steps of:
(a) continuously pulling a first elongated web of heat sensitive thermoplastic pouch forming material having a thickness in the range of 0.001" to 0.008", at a high speed through a web printing station, a web collating station, an electron beam curing station and a web cutting station, (b) applying an E.B. curable coating to the wide seal areas of a first surface of said first continuous web as it is pulled in a continuous motion through said web printing station, to render the coated areas bondable at said wide seal area, (c) directing a second web of like pouch forming material in a face-to-face relationship with said first web after passage of said first web through said printing station to form an interface therebetween in said collating station, (d) continuously pulling the first and second webs through said electron beam curing station and irradiating the entire interface with a curtain of electron beam radiation emitted from an electron beam emitting device to instantanously bond the buried interface bondable areas of said webs at a temperature below the distortion temperature of the thermoplastic thin film webs, while subjected to the tensile stress necessary to continuously pull the webs through the curing station, (e) cutting the pouch from the web along a line disposed outwardly from the inner edge of the seal area and along said opening line to form an open pouch as the webs are pulled through said cutting station.

2. A method of forming a plurality of pouches from at least first and second elongated webs of pouch forming roll stock which is not inherently E.B. bondable comprising the steps of;
(a) continuously pulling said first web through a printing press at a predetermined high speed and printing a print image on said first web at predetermined locations along the length thereof as said web is pulled continuously through said web printing press, (b) directing said first web, at said printing speed, from said printing press to a pattern bond coater arranged in line with said printing press, (c) continuously pulling said first web through said pattern bonder coater at said printing speed and applying a pattern of an E.B. bondable coating to a first face of said first web in register with the printed images on said web as said web is pulled continuously therethrough, (d) guiding a second web of pouch forming material to locate a first face thereof in a face-to-face relationship with said first face of said web to form an interface therebetween, (e) continuously pulling the first and second webs through an electron beam emitting device in said face-to-face relationship at said predetermined printing speed to thereby irradiate the entire interface of said web with a penetrating beam of electron beam radiation emitted from said electron beam emitting device to thereby instantaneously bond the webs at said buried interface, and (f) cutting said webs to remove individual pouches from the bonded webs.

3. A method as claimed in claim 1 or 2 wherein said first and second webs are each formed from a heat sensitive thermoplastic material having a thickness in the range of 0.001 to 0.008".

4. A method as claimed in claim 1 or 2 wherein the bondable areas of the web form upto 50% of the area of the entire interface.

5. A method as claimed in claim 1 or 2 wherein the heat sealable webs are bonded to one another at the precoated pattern areas and at a temperature substantially below the heat sealing temperature of the material from which they are formed.

6. A method as claimed in claim 1 or 2 wherein at least one of said webs is in the form of a multi-ply laminate consisting of at least one ply made from a heat sealable thermoplastic material and at least one ply of aluminium foil, or a ply of metallized film or foil substrate, the multi-ply laminate having a combined maximum thickness of about .008".

7. A method as claimed in claim 1 or 2 wherein at least one of said webs is in the form of a multi-ply laminate consisting of at least one paper ply and at least one ply of heat sealable thermoplastic material, the multi-ply laminate having a combined maximum thickness of about .008".

8. A method of manufacturing a square bottom bag having a pair of longitudinal side gussets each formed along a central gusset fold line located centrally between a pair of outer gusset fold lines, a bottom wall formed along a transverse fold line and a longitudinal lap joint, from a continuous web of bag forming material having oppositly disposed side edges comprising the steps of;
(a) continuously pulling a web through a printing device in a flat unfolded configuration, the printing device being operable to apply an E.B. curable coating in a predetermined pattern to selected portions of an inner face of said web, said selected portions comprising, (i) a marginal edge portion extending along a first of said free edges of said web, (ii) a plurality of longitudinally spaced transversly extending portions, said transversly extending portions being located on the bottom wall forming portions of successive bag forming lengths of said web, (iii) a triangular shaped portion associated with each outer gusset fold line, each triangular shaped portion having an apex located on and its opposite side bridging its associated outer gusset fold line at said each of said transversly extending portions, (b) folding the web upon itself along said gusset fold lines to form a sleeve with each central gusset fold line disposed inwardly from its associated outer gusset fold lines and the marginal edge portion overlying a second marginal edge portion of the web whereby the coated areas are located at an interface between two layers of said web, (c) continuously pulling the folded web through an E.B.
radiation device to radiate the web and thereby bond the coated areas at their interface to close the bottom of the bag and secure the marginal edges, (d) transversely severing the web to form a plurality of independent bags which, upon opening, will articulate along the transverse fold line and the edges of the sealed interfaces of the bottom wall forming portions to form a square bottom.

9. A method of making a satchell type square bottom bag having a gusset extending along the bottom edge thereof and a pair of side seams extending normal to the bottom edge, said gusset being formed by a central fold line and a pair of spaced parallel side fold lines, said bag being formed from a continuous web of bag forming material comprising the steps of:
(a) continuously pulling said web through a printing device in the flat unfolded configuration, the printing device being operable to apply an E.B. curable coating in a predetermined pattern to selected portions of an inner face of said web, said selected portions comprising;
(i) a plurality of longitudinally spaced transversely extending portions, said transversely extending portions including side seam forming portions and first and second bottom corner forming portions extending longitudinally from each side seam forming portion to meet one another at the central fold line, said first and second bottom corner forming portions having first and second sections arranged on opposite sides of their associated side fold line, (b) folding the web upon itself along the central gusset fold lines and the side fold line to dispose the central fold line inwardly from the side fold lines with the side seam forming portions arranged in a face-to-face relationship to form a bondable interface therebetween, the first corner forming portions and the second corner forming portions arranged with their first and second sections disposed in a face-to-face relationship forming second and third bondable interfaces, (c) continuously pulling the folded web through an E.B.
radiation device to radiate the web and thereby bond the coated areas at their bondable interface, (d) transversely severing the web along transversely extending bonded seal lines to separate individual bags from said web.

10. An apparatus for forming an open pouch, the pouch consisting of two panels which are secured to one another along a seal line which extends about an article storage compartment located between two panels and which is open along an opening line extending between opposite ends of the seal line, the apparatus comprising;
(a) means for pulling first and second webs through said apparatus, (b) at least one printing press arranged in line with at least one of said webs for applying printing to a web passing therethrough, (c) rotogravure coating means for applying a pattern of a coating to a portion of a first surface of said web to render it bondable along a line having the configuration of said seal line and second portions thereof non-bondable in the area of said first web to be used in forming said article storage compartment, (d) collating means for collating said first and second webs in an overlying relationship with said first and second surfaces in intimate contact with one another at an interface, (e) electronic beam curing means having a curing station in which an electron beam is web width curtain is emitted, (f) means for contniuously moving said intimate contacting webs through said curing station whereby said penetrating electron beam irradiates the buried interface by directing radiation through the first surface to reach the second surface and thereby instantaneously bond said bondable portions of said webs together in said pattern; and (g) means for cutting said webs while in concinuous motion along a line extending about the periphery of the article storage compartment of each pouch, said line being disposed outwardly from the seal line and extending along said opening line to provide an open pouch.

11. A method of making plain or printed pouches and bags, up to 5,000 per minute and beyond, from thin gauge, 0.001"
to 0.008", heat sensitive extensible films such as polyethylene with flat wide Electron Beam radiation heat-seal-like seals typically 1/2" wide completely across the full film web width and longitudinally along the film web while the web is being pulled from the film unwind roll unit through the printing press units and the Electron Beam curing and sealing unit and the cut off and collating units in continuous motion at web speeds around 300 feet per minute and under controlled machine web tension essential to keep the film web tracking in a straight line and to maintain colour to colour print register and to maintain printed pattern repeat length and seal to print and cut off edge register while making the instantaneous chain reaction Electron Beam curable adhesive seals when passing under the Electron Beam radiation unit without detrimentally heating or mechanically contacting the polyethylene-like web sufficiently to lose the machine web tension control and the register of print to seal and seal to cut off edge and maintaining the preset pouch or bag cut off length.