Note: Descriptions are shown in the official language in which they were submitted.
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
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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
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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
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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
. . . =
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` 30 _______________ _
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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
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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 _
/
/
/
`'~`, /
~ /
/
- 9a -
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. .
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~6~
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
- 10 --
.
;
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
~,~ .
~: . ~
`'.'
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.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
,
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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.
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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
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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
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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.
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~ ~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
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:,
, .
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
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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
~,
19 -
.
.
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
-20-
~.~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.
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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".
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