CA 02515934 2005-08-15
IN TIEIE UNT)CED STATES PATi~NT AND T)ItADFMaRx OFFIC)C
TRANSVERSELY SEALED CON~".AINER
CROSS REFERENCE TO RELATED APPLICATIONS
[U001] This application claims priority tinder 35 U.S.C. ~ 119(e) from U.S_
provisional
Patent Application No. 60/641,944, filed on Au4ust 16, 2004.
~AC~OROUND OF THE DISCLOSURE
[oDDZ] The present disclosure generally relates to an improved plastic bag for
use by itself
or for use as a liner in conjunctiva with a bag having multiple paper ply
construction.
[DDD3] More specifically, the disclosure is directed to a seamless tubular
plastic liner for
a multilayer satchel bottom type bag. Such bags are la~own izx the art, an
example being
disclosed in U.S. Patent Nv_ x,553,943 which is herein incorporated by
reference. Satchel
bottom bags are formed by folding a plurality of layers of kraft paper into a
tube. The
layers are arranged in stepped configurativz~ foz~ adhesive banding. A plastic
liner or pouch
is inserted into the tube and secured by adhesive to the top, or the mouth end
of the tube.
[OUOA~] plastic lined multilayer paper bags are used to package bulk granular
or powdered
products such as flour, cam meal, sugar, powdered milk, and similar
commodities as well
as ather powdered or granular materials. The plastic liner may be either an
additional
plastic ply bonded to the inner most paper ply, or a free-floating plastic bag-
within-a-bag
as described herein.
[D005] Plastic bags made of polyethylene or other polymeric materials are
common
packaging containers for a variczy of products and commodities. Such bags may
be used
either by themselves or as liners for paper bags_ The manufacturer of the bags
seals one
end ofthe bag (called the "manufacturer ez~d" or "plant ez~d") which fozrz~s
the bottom seal
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of the bag when the bag is in use. The otlxer exxd (called the "customer end")
is left open for
the purchaser of the bag to fi11 with its product and close and seal. The
customer end forms
the top end of the bag through which material is introduced into the interior
of the hag.
[0406] When a polyethylene bag is filled with powdered or granular material
and sealed,
air or other gases may become trapped in the bag. Tllis can create air pockets
in tlae bag,
which if not allowed to escape, can result in problems wJ~ez~ tl~e bags are
stacked for
shipment, hor example, trapped air prevents the ban from conforming to the
powdzred or
granular contents creating air pockets. As bags are placed on top of each
other, such as for
shipment on pallets, the air bubbles make the stack of bags unstable and prone
to tipping,
thus lixnxting the number of bags that can be stacked for shipping. Also, as
additional bags
are placed on top of the hag containing the trapped air, the air pockets are
compressed due
to the additional weight, increasing the pressure inside the bag. If enough
weight is placed
on the bag with the trapped air, the increased air pressure may rupture the
bag, resul tang in
spillage ofthe contents. Therefore vezrting the air from the bag facilitates
stacking of bags
for shipment and reduces the risk of bag rupture.
[000T] Alternatively, venting of the plastic bag may not be desirable iu1 all
situations,
particularly when the contents are toxic or hazardous, such as various types
of chemicals.
In this situation, reinforcement of the seals is required to zrniunizxxize the
possibility of
rupture during transportation and handling.
[0008] More particularly, the present disclosure relates to a seamless
polyethylene, or
similar polymer xnateri al bag, that has a maze vent allowiirg air to escape
after the bag has
been sealed while inhibitizig the ingress of air, moisture and other
contaminants. Such
vents are lanown in the art and typically consisF of one or more heat seals
having a gap. The
heat seals bond the fi-ont and rear walls ofthe bag together. For example,
U.S. Patent No.
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6,491,433 teaches three heat seals, each with a gap being offset from the gap
in the adjacent
seal or seals.
[0009] One method of manufacturing a vented seal bag is typically accomplished
by
folding a sheet of polyethylene oz similar material into a tube. When the
sheet is folded,
overlapping edges form a longitudinal seam in what is typically the back of
the bag. The
overlapping edges are then sealed with a plurality of interrupted heat seals.
The
interruptions in the heat seals are offset from the interruption in adjacent
heat seal or seals,
forming a tortuous path :&orn the interior of the bag to the exterioz,
allowing trapped air to
be expelled. See U.S. Patent No. 6,170,9$5_
[D010] These longitudinal seams are prone to failure, causing leakage and
contamination
of the material contained within the bag.
[0411 ] The present state of the art uses a flat film that is folded to create
bags with seams
along the longitudinal axis of the bag that incorporate a vent. These seams
are prone to
failure, resulting in spilled product and associated wasted expense.
SUMMAIIfY OF TAE DISCLOSURE
[00'12] This disclosure may be described as a novel and improved plastip
litter and
multilayer paper satchel bottom bag incorporatiztg such a liner. The plastic
(or "poly")
Inner may be used by itself as an independeaat package, or may be incorporated
as part of a
bag-withixt-a-bag. The poly liner is placed ~nvithin a multilayer paper
satchel bottom bag for
added strength and protection.
[0013] The poly liner is formed from a seamless tube of polyethylene or
similar polymer
material folded flat forming a front panel and a rear panel. A plurality of
heat seals are
made across the bottom of the plastic tube transverse to the dizection of the
bag. In one
embodiment, a first solid heat seal and a second interrupted heat seal are
created across the
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bottom or satchel end of the bag, sealing tb.e bottom of the liner and forming
a vent channel
between the heat seals. The interruption in the second lxeat seal fozxns the
vented seal gap.
The vented seal gap is in communication with the interior space of fhe bag.
Next, one or
both of the front and rear panels of the liner are perforated within the
ve><at Channel between
the heat seals with a plurality ofperforation holes forming the c~t~rior vent-
(0014 When the bab has been filled and sealed, an increase in pressure w-ithin
the baj w~ili
cause the front and rear parcels of the vent channel to separate allowing air
to pass through
the vented seal gap, through the vent channel, and to be exhausted through the
exterior vent.
When pz~essure has been reduced through venting, the front and rear panels of
the vent
cliannel collapse against each other, closing off the passage to the exterior
of the bag and
thus sealing the bag against entzy of moisture or other contaminants from the
outside-
[0015~ In alternative ernbodirzaents,. maze blocks may be formed within the
maze vent
channel, substantially perpendicular to and in communication with one or more
of the
transverse heat seals. The maze blocks function to form a tortuous patb~
tbzough the vent
channel trapping powdered or granular product that may enttez ttte vent
channel. Product is
retained in the vent channel preventing clogging of the exterior vent and/or
leakage of
pmduct.
(aalsl A machine known in the art, a W&H Rocaliner, is rnvdihed to manufacture
bags
having the maze vent described herein. The typical Rotaliner has a drum with a
sealing bar
havizag a sealing surface. The sealing bar is modified by maclvning a gap in
the sealing
surface corresponding to the second heat seal to create an interruption in the
second heat
seal forzxxing the vented seal gap. If a bag is to be manufactured having
amaze blocks, weld
beads are created on the Rotaliner sealing bar in communication with and
substaaitially
perpendicular to either the first or second heat seal and machined.
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[0017] Uxxder certaixr cixciunstances, venting of the plastic liner may not be
desirable. It is,
therefore, necessary to reinforce the bottazcz Ixeat seal to prevent rupture.
Multiple solid
heat seals are provided at the bottorxz o:f the liner, instead of oz~e
interrupted heat seal and
one solzd heat seal.
[009 $] In one embodiment of this disclosure, it is envisioned that a plastic
liner of the t5,~pe
described herein zs used is conjunction with a satchel battorn bob constructed
of a p tuz~alzt~f
of papEr layers or plies, such as kra$ paper or high performance paper as is
generally
known in the art. A plurality of paper plies are folded into a tube wherein a
plastic liner is
inserted into the tube and secured by adhesive to the innerztxost ply near the
top ar mouth
end.
[0019] The plastic liner is heat sealed at its bottom, or satchel end, before
insertion i nta the
paper tube. The plastic liner is else temporarily secured by adhesive to the
inner paper ply
of the back wall of the bag. 'this is to secure the liner during the satchel
folding process.
The paper plies are folded to form a flat satchel bottom. After bulk product
is introduced
into the bag, the mouth of the plastic liner may be heat sealed closed. The
paper plies at the
mouth end have a stepped configuration for adhesive bonding. The paper plies
are ;Folded
over and secured by adhesive, tlxus enclosing the plastic liner aztd its
contents.
[0020] The satchel end of the plastic liner is folded within but not
adhesively secured to
the folds of the plies of the satchel end. The liner is thus secured and held
flat during
transport ofthe bag. As the bag is unfolded for filling, the plastic liner is
released from the
folds of the satchel end and is a free-floating bag-within-a-bag secured only
at the top to
the innermost paper ply.
(0021 ~ Zn another ezn,bodiz~nent of the present disclosure, a patch is
provided on the outside
of the folded satchel bottom_ The patch may be made of kraft paper or other
suitable
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material and may be of one or more layers and is adhesively affixed to the
outside of the
satchel bottom. The patch provides additional reinforcement to tl~e satchel
bottom.
[D022~ In yet another embodiment, it may be desirable to provide an easy
opening bottom
to the ban of the present disclosure. lzr this embodiment, na adhesive is
applied to the daps
of the satchel bottom. A patch is adhesively applied to the outside of the
satchel bottom.
An opener step is pro~~ided between the patci~ cud the daps of the satchel bor
~orz. Thw
opener strip terminates at a cuff area at one side ofthc patch. A pair of
slits are provided
in the patch on either side of the opener strip to farm the cuff The opener
st3rip xnay be
fozzned of plastic, string, or other strong flexible rnaterial_ A user grips
the cuff pulling
away from the satchel bottom. As the user pulls the cuff, the opener strip
tears the patch
exposing the satchel flaps which are easily opened because there is no
adhesive securing
them in place.
~atfEF DESCRIPTION OF THE DRAWINGS
[DD23] FIG. 1 is a view of a poly bag having a maze vent of the present
disclosure;
[0024] FIG. 2 is a view of a poly bag having another embodiment of a maze vent
of the
present disclosuze wrath maze blocks perpendicular to the heat seals;
[0025] FIG. 3 is a view of a poly bag of the present disclosure having a
double bottom seal;
[0026] FIG. 4a is an alternate cota~guration for the maze vent of the present
disclosure;
[ODZ7] FIG. 4b is another alternate configuration for the maze vent of the
present
disclosure;
[8D28~ FIG. A.c is another alternate configuration for the maze vent of the
present
disclosure;
[oa~s7 FIG. A.d is another alternate coni~iguration Far the maze vent of the
present
disclosure;
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[003D] FIG. 4e is another alternate configuration for the maze vent of the
present
disclosure;
[043'x] FIG. 4~ is another alternate configuration far the maze vent of the
present
disclosure;
[Od32] FIG. 4g is another alternate configuration for the maze vent of the
present
disclosure,
[0033] FIG. 4h is another alternate cozrfiguration for the maze vent of the
present
disclosure;
[0034] FIG. 4i is another alternate configuration for the maze vent of the
present
disclosure;
[0035] FIG. 4j is another alternate configuration for the maze vent of the
present
disclosure;
[036] FIG_ 4k is axtother alternate configuratiort for the maze vent of the
present
disclosure;
[0037] FIG. 5 is a perspective view of the multi-ply plastic lined bag with
satchel bottom,
partially broken away, and having a pinch closure-type open top ready to be
filled by a user
with a commodity or the like;
[0038] FIG. 6 is a front elevation view of a znulti-layer bag blank showing a
main fold line
and slits for forniing a satchel bottom;
[0039] FIG. 7 is a front elevation view of a tube blank with the multiple
paper plies ut one
side of the being folded upwardly around the main score line to thereby define
upper and
lower paper Flaps and four diagonal bend Iines in the paper ply flaps, both
above and below
the main scare line, and foldably holding at the upper flap the plastic liner;
[0040] FIG. 8 is a detailed view of the folds of the satchel bottom;
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[004.11 p')'G. 9 is a detailed view of the folds of the satchel bottom of a
bag having an easy
oparing feature;
[002] FIG. 10 is a detailed view of the completed satchel bottom with
reinforcing patch.
bETArf,Eb bESCI~TPT10N
[0043] ~Vhilo the prcs~nt disclosure will be described fully her~inafier with
refercnc., to
the aeeompanyino drauTuigs in which.a pa.~icular embodiment is sliourn, it is
understood
at the outset that persons skilled in the are may modify the disclosure herein
described
while still achieving the desired result of this disclosure. Accordingly, the
description
which follows is to be understood as a broad informative disclosure directed
to persons
skilled in the appropriate arts and not as limitations of the present
disclosure.
[OD44] FIG. 1. depicts the arrangement of an embodiment of the present
disclosure. A poly
bag 10 is formed from a seanrAless tube o;f polyetlrylezre ox similar polymer
material creating
an interior and exterior. The tube is folded upon itself forming a first edge
Fold 12 and a
secoxzd edge fold 14 and a Front wall and a rear wall- When the seanrtless
tube is cut to the
desired size, it will have two ends. ')-he first end 16, called the
manufacturer end or the
plant end, is typically the bottom of the bag. The second end 1.8, called the
customer end
because the bxg purchaser seals this errd aver it fills the bag with product,
is Left unsealed
and is typically the top of the bag. Irvcated at the bottom end afthe bag are
at least two heat
seals, the first 20, a solid bottom seal, located nearer the manufacturer end,
closes the
bottom of the bag. The second 22, an intercepted seal, is located above the
first heat seal
20 and is in contact with the interior space of the bag. The second heat seal
22 is
interrupted by a vented seal gap 24. Tlte solid bottom seal 20 and the
interrupted seal 22
are substantiallyparallel to each other and define the vent channel 26 as the
space between
them. Finally, there is an exterior vent 28 to allow the air to pass from the
vent channel 26
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to the exterior of the bag. In the embodiment shown in FIB. 1, the exterior
vent 28 takes
the form of a plurality of perforation holes ixc both the front attd rear
walls of the vent
channel 26. The exterior vent 28 may consist of any suitable means to allow
air to escape
the maze ve~at clxazxziel 26 to the exterior of the bag. The vented seal gap
24 should be
offset rrom the extErior vent 28 to inhibit loss of powered or ~-anular
material contained
w~itl~in the bag 10.
[0045] FIG. 2 depicts an alternative embodizzaent rvith additional heat seals
placed
substantially perpendicular to the solid heat seal 20 and the interrupted heat
seal 22 to
create maze blocks 30 in the vent channel 26. The maze blocks 30 alternate in
communication with either the second heat seal 22 or the first heat seal 20.
Adjacent maze
blvclfs 30 define a chamber 32 between them. ~,'he n~uxnber of chambers 32 is
dependent
on the number of maze blocks 30 with an embodiment Laving multiple maze blocks
30
having a plurality o~chambexs 32.
(0046) An alternate embodiment, shown in FIG. 3, may be employed when it is
xtot
desirable to have a vented bag. When the contents of the bag are toxic or
hazardous, it may
be preferable to assure that zoo product escapes the bag. Jn this case,
rupture of the bottom
seal is prevented by providing a double reinforced seal as shown in FIG. 3_ In
this
embodiment, two solid heat seals 20 are used to seal the bottom of the poly
bag.
[0047 It slxould be understood that the maze veztt is adaptable to many
variations and
configurations and still be within the scope of the present disclosure. As
illustrative
examples only, and in no way intended td limit the scope of the present
disclosure, FIGS.
4a through 4k show multiple configurations for the xxi:aze vent. FIG. 4a shows
a poly bag
1 p with a maze vent laaviztg an interrupted heat seal 22 with two vented seal
gaps 24
located at either side of the seal, and the exterior vent 28 comprising a
plurality of
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perforations located at substantially the center of tb:e vent channel 26. FIG.
4b shows a
maze vent having an abbreviated heat seal 34. The abbreviated heat seal 34 is
located
between the solid heat seal 20 and the intert~xpted heat seal 22. The
abbreviated heat seal
34 is aligned with anal longer than the vented seal gag 24 so that portions of
the abbreviated
seal 34 are vertically aligned with portions of the W terrupted heat seal 2?
ammecliately
adjacent to the vented seal gap 24. FiG. ~c is a vaziatioz~ of th.e maze vent
of FIG. =la with
the addition of maze blocles 30 in cooperation with the interrupted heat seal
22 ors either
side of the exterior vent 28. FIG. 4d is a variation of the maze vent of FIG.
4c, adding a
zxxaze block 30 in cooperation with the solid heat seal 20 between the
perforations of the
exterior vent 28. FIG. 4e shows a variation of the maze vent of k'IG_ 4b,
adding maze
blocks 30 in cooperation with the interrupted 22 and solid 20 heat seals
between the
abbreviated heat seal 34 and the exterior vent 28. FIG. 4f shows a maze vent
having a
substantially centered vented seal gap 24 and an abbreviated heat 34, with an
exterior vent
28 on either side of the abbxeviated heat seal.
[0048] k~G. 4g is another embodiment of the maze vent, having twa intemxpted
heat seals
22 wherein tlxe vented seal gap 24 in each interrupted seal is located adj
acent to an opposite
side of the poly bag. In the embodiment of FIG. 4g, the exterior vent 28 is
vertically
aligned with the vented seal gap of the innermost interrupted heat seal.
(D049] FIGS. 4h through 4k show embodiments of the maze vent having two
interrupted
heat seals 22 and no solid heat seal. The exterzzat vent, therefore, comprises
a seal gap in
the bottom heat seal. Instead of air being vented through the sides of the
poly bag, the gap
in the bottom heat seal allows air to vent out the bpttom pf the tubular poly
bag body. pIG.
4h shows a maze vent having two interrupted heat seals 22, vc~ith the vented
seal gap 24 and
the exterior vent located at opposite sides of the poly bag. FIG. 4i shows a
maze vent with
lyage 10
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an inner interrupted heat seal having two vented seal gaps 24 located at
opposite ends of
the heat seal azxd an outer interrupted seal with the exterior vent 2$ located
substantially in
the center. FIB. 4j shows a maze vent having an inner intemzpted heat seal
having a vetzted
seal gap 24 offset to one side of the seal and an outer interrupted heat seal
with two exterior
vents 2~ both offset to the opposite side o.f th~ po'y bad as the inner seal
jap. f'TG. -lr_:
shows a rrzaze vent r~~ith aii inner interrupted )aeat seal l~avzng a ented
seal gap 24 ~oc~l.c'
substantially in the center of the itaner heat seal and an outer interrupted
seal with the
exterior vents 28 located at opposite ends of the outer heat seal.
[oo~a3 Additionally, the present disclosure is directed towards a method for
manufacturing such a poly bag with a maze vent. The method for zaanufacturing
a bag
having a maze vent as described herein requires modificatxo~. of a
Windmi5eller &
Hdlscher (W&Fi) Rotaliner, a machine kn.vwn in the art. A W&H Rotaliner has a
sealing
drum housing five sealing stations. Each sealing station has a sealing bar
with a first
sealing surface and a second sealing surface spaced apart and substantially
parallel to each
other. Each sealing station makes one set of seals across the bottom of the
polyethylene
tube per bag. The rotating seal bar makes a series of five bags before a bar
has rotated back
to its original position. A notch is machined in the second sealing surface
corresponding to
the inner heat seal 22 creasing the varted seal gap 24.
[Q051] Polyethylene or other suitable material film is extruded into tubes and
compressed
flat fozxr~,i,x~g a front wall and a rear wall. The flattened tube is then fed
into the modified
W&H Rotaliixez wherein the first bottom heat seal 20 and the second inner heat
seal 22 are
made across the bottom end of the poly tube, and the exterior vent 2$ is
formed by making
perforation holes between the seals. Perforation holes may be formed by any
suitable
means known in the art inc lading mechanical or needle perforation, electrical
disch~~rge ar
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laser. Additionally, although the perforations generally described herein as
penetrating
both the front and rear walls of the vent channel 25, it is also envisioned
that perfaratians
of only one wall, such as by controlled laser machining, also fall within the
scope of this
discl4sure.
X0052] The maze blocks iU are formed by making at least one maze black surface
oz~ the
seal>Iig oar. '1-lus is doztc byweldint at least one bead ofmetal, in
~.ozzzrA~uzaicatic~n with and
substantially perpendicular to either the first heat sealing surface or the
second heat sealing
surface. The weld bead or beads are then mach~uoud to proper dimensions. In
one
embodiment, the first maze block surface is in cvmznuzzicatxon with and
substantially
perpendicular to the second heat sealing surface. The second maze block
surface in
communication with and substantially pexpexxdicular tv the frst heat sealing
surfacE.
Additional maze block surfaces xnay he added, alternating in communication
with the
second heat sealing surface ao.d the first heat sealing surface.
[0053 ~n oae embodiment, the heat seals 20, 22 and the maze blocks 30 each are
typically
II16 inch wide. The solid bottom seal 20 is typically located 5/8 inch above
the bottom
edge 16 of the #lattened poly tube. The inner seal 22 is typically located 1-
1/8 inch above
the bottom seal 20. The vented seal gap 24 in the inner seal 22 is typically
located :~ inches
from one of the side folds 12 or 14 in the poly tube and is typically 118 inch
to 114 inch wide.
The perforation holes forming the exterior vent 28 are typically located to be
centered 2
inches from the fold in the poly tube opposite the side where the vented seal
gap is located.
[0054] In one embodiment having maze bloclCS 30, the first maze block is
typically located
2 inches inward from the vented seal gap 24 azxd itt communication with the
interrupted
heat seal 22. Additional maze blocks may be located typically in succession at
4 inch
intervals, alternating in communication with the first heat seal 20 and the
second heat seal
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22. The maze blocks typically are 3I4 inch long and 1/16 inch wide. however,
in alternate
embodiments, such as those shown in FIGS. 4c and 4d, zxxaze blacks 30 may be
pasiiianed
at the end of heat seal 22 directly adjacent to the vented seal gap 24.
[Op55] In the disclosed embodiments, the microperfoxation holes forming the
exterioz vent
28 are typically l, mzn in diameter and located to 1~~ centered 2 inches from.
the sid~:: fold
opposite to the veztted seal dap 24 a.~d at least l; 4 inch abo sw the solid
bottom seal ~0. It
is envisiozted that from 2 to about 10 perforations provide an optimal range
for a variety of
bag contents to be vented although any number of perforations may be used and
sti 11 fall
within the scope of the present disclosure.
(0056] After material is introduced into the poly bag 10, any trapped air is
al lowed to pass
through the veztted seal gap 24, into the vent channel 26, and is exhausted to
the exterior
of the bag ih~rough the exte~zor vent 28. Amy material that passes through the
vented seal
gap 24 into the vent channel 26 is trapped within. In an exinbodiment having
multiple maze
blocks 30, chambers 32 are formed between adjacent maze blocks, which retain
material
that has entered the vent channel 26, inhibiting it firm reaching the exterior
vent 28.
(0057 In addition, the poly bag of the preseztt disclosure may be incorporated
as part of a
mufti-component flexible package. For exazztple, mufti-ply paper bags have
long been
known in the art. Such bags are generally formed froxxx two or mare layers of
paper bonded
together and folded to farm a bag. One type of such bag is a "satchel bottom"
type bag.
.A, satchel bottom bag forrxted from multiple paper plies is folded at the
bottom and secured
by adhesive. When the bag is opened, the bottom is flat, allowing the bag to
stand while
being ~lled_ ,A satchel bottom bag may be farmed with or without side
gerssets. Satchel
bottom bags znay have a plastic liner for contaxz~xng granulated or powdered
product
therein.
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[005$] The poly liner having a maze vetxt as described herein, may be
incorporated into a
satchel bottom mufti-ply paper bag as a bag~within-a-bag for packaging bulls
granulated or
powdered material. FIG. 5 shows such a satchel bottom bag 50, with a poly
liner 10
disposed within a rztultiple ply outer tube 52. The multiple ply outer tube 52
is fotzned
from a plurality of c.ontisuous laterally ofFset plies 54, 56, and 58. The
plies 54, 56, arid 58
axe made of a non-heat sealable material, preferably paper, such as used in
~h~ell. '~ ~~wm
industrial packaging bags sold by Semis Company, Ins. under its trademark AIRS-
TITS.
[0059] The inner poly liner 10 comprises a searstless heat sealed tube, as
described herein,
that is fed to a bag-making device, which forms a bag blank. The inner tubular
ply 10 is
narrower in width than one-half the perinr~etex of the paper ply 58. This
results in a lateral
space, or gap, between the poly liner 10 and inner most papex ply 58. The
tubular blank is
generally designated as 60, as shown in h'IG. 6, which blank may be produced
on a
cvz~ventional stepped end tuber device. The overlapping edges ofthe multiple
paper plies
54, 56, 5$ are adhesively bonded to form the seams along the overlaps,
preferably by
applying a hot melt adhesive. As the blank 60 is formed, the poly liner 10 is
circumfere~ntially bonded at 62 adjacent floe top edge of the paper ply 5$,
which ply is the
innerxztost contiguous paper ply. The bonds 62 are a series of dots of
adhesive around the
outer circumference of the poly liner 10 generally near the open end. However,
below the
bands 62, the poly liner 10 is freely and non-attachably retained within the
paper tube 52,
except for temporary adhesive at the back side and near the bottom of the tube
blank 60,
which momerita~ily aid in the bottom folding process to form the bag_ ,~4lter
completion of
the bag, they serve no fuc~Gtivn, dissipate, and do not impede the loose
folding of the bag,
or its ability to be retained in a fully detachable manner within the paper
plies. The paper
plies 54, 56, 58 are bonded together by dots of adhesive extending
circumFerentially
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around and near the top open end of the blank 60, as shown at reference
numerals G4, b6_
The dots of adhesive 64 are provided to adhere ply 54 to ply 56 and dots of
adhesive 66 are
provided to attach ply 56 to ply 58. The li;ae of dots of adhesive 64, 65 are
also
longitudinally offset front to back due to the stepping of thv paper plies 54,
56, 58.
Ioaso~ The em'oodimezit of the op~:n top iii FIG- ~ has a stepped
arrangez~.~.ez~t of the plus
54, 56, 58; however, a flush cut top, wherein tile plies 5~, 56, 58 arc cut
straight across ~:~rtl
the top of the poly liner 10 to provide a common upper periphery, is also
acceptahle_
Typically, a bag having flush-cut plies would be closed by sewing; however,
the p<71y liner
would still be heat sealable and severable.
rQ061 ~ The closure of the open top of FIG. 5 is accomplished by reactivation
of a Itot melt
adhesive strip 6$ located oxt ply 56 and a hot melt adhesive strip 70 located
on ply 58. The
hot melt adhesive strips on the stepped front and hack sides are
longitudinally offset due to
the Stepping, so that the upper end may be passed through a folding machixle,
and 6y means
ofpressure rollers, the stepped plies 54, 56, 58 are overlapped and adhesively
joined in a
standard way as explained iz~ Z3_S. Patent No. 5,2$1,027.
[0062] Also, in regard to closing the top end, the upper end of the poly liner
10 would be
heat sealed to closure and then, in preferred form, severed by pressure
rollers applied to the
exterior of the paper ply 5$, whereby the poly liner 10 will detach below the
line of
adhesive dots 62 to result in the freely detachable arrangement of the pouch X
0 as a
bag-in-a-bag.
I0063~ rt should be understood that other types of closures are alternately
envisioned for
the open end of the present bag 60, including a pinch-type closure, adhesive
closures other
than reactivatable hot melts, or mechanical closures, such as staples, clasps,
zipper
assemblies, etc. The preferred forrz~. of the invention, regardless of how the
paper plies are
Page 15
CA 02515934 2005-08-15
closed, envisions the heat sealing and severance of the top of the poly liner
10 so that the
bag is detached thereat.
[p064] In connectiozt with any of these typos of open end closures, the
formation of the
satchel bottom ofthe bag will aaow be described as shown, in FIGS. 6 through
10.
[0065] As previously rlotc:d, the bag blank. 60 is the first s tep of Fom~ina
the satchel bottom.
FIG. 6 is the "back" sidr: of the bag 50 for proposes of exc~lan_~tio~~Slits
are first i:ut
through the front and back sides of exterior ply 54 whereby two parallel slits
S4 are made
in the front side, and twa parallel slits $4 are made in the back silo of ply
54. Next, two
parallel slits 86 are cut through both the fe-ont and back plies 56 as shown
in dashed lines in
FIG. 6. In the disclosed embodiment, the slits 84 are about 3 inches long,
made about 4 to
4-112 inches inwardly of the lateral edges of the hag. The slits 86 are
approximately 2.-1.12
inches long and inwazdly parallel to slits 84 at about 3/4 to 1 inch. The
width of the bag 50
measured across the blank fi0 at the outer ply 54 is standard size in the
range of about
19-I/2 to 20 inches. Each pair of slits is cut through the bottom edge of the
respective ply.
These dimensions are useful for understanding the preferred embodiment, but
are not to be
understood as limitations to flee in~rentxon. While the greferred embodiment
has a non-slit
innermost ply 58 and two overlying slit plies 54, 56, the invention erxvisions
a bag 60 with
from 2 to G paper plies overlying the ply 58; the inner ply 5$ being xxon-slit
and the others
being slit wherein each ply is slit inwardly at about a 1/2 to 1 inch,
distance parallel to the
slits of the preceding adjacent overlying ply_ The slits ate sequentially
shorter by 1 /4 to 314
inch less than the preceding overlying ply. The goal is to optimize the
lateral distance
between the slits on sequential plies so that later exposed geometric zones of
adhesion
surfaces are maximized for effective bonding.
Page 16
CA 02515934 2005-08-15
(0066] A gap laterally offsets the poly liner 10 from fine plies 52 by 1/4
inch in the
exemplary ernbodiment. As part of the blank forming process, the poly liner 10
i s heat
sealed closed along its lower edge as previously described herein, the bottom
edge of the
poly liner 10 being closely adjacent and parallel to the lower edge of the
innermost ply 58_
[0067] As sha~~~n in FIGS. 6 and 7, a main score or crease line ?? zs x.xade
it-ansversely
across the outer tube 52 arid thereby across all paper plus 5 ~. ~~_ ~~'. Also
v; ith refcrenr,_
to FIG. G, in the disclosed embodiment, th,e main score line 72 is made about
8 inches
upward from the bottom edge of the front side outer ply 54.
(0068] In FiG. 7 the satchel bottom of the bag takes on a more clearly
definable form and
is generally denoted by reference numeral 70. A score line 72 will become the
transverse
center axis of the bottom of the satchel bottom as will be understood
hereinafter. FIies 54,
56, 5$ are folded back with the poly liner 10 only folded to one side of the
main score line
72. Thus, the poly liner 10 is retained at one side of the main score line and
is tucked in
triangular folds 10a, 10b resulting from the diagonal fold lines 74,76 of the
outer tube 60.
Tlae back of plies 54, 56, 5$ are similarly arranged to create diagottal fold
lines 78, 80. It
will be apparent that tl~e non-slit innermost paperply 5$ mai»tains a
continuous lower edge
generally denoted at 82. The paper plies 54, 56, 58, in addition to the poly
liner 10, leave the
diagonal bend lines 74, 76, 78, and 80, in common, whi ch, by vixtue of the
stepped
arrangement of the outer tube 52 and the slits $4, $6, create various
symmetric geometric
exposed zones for adhesion as shown. These zones will be subsequently
functional as
areas of very effective adhesive zzxating for completing the satchel bottom
70. The blank
64 for forming the satchel bottom 70 is not symmetrical about the main score
line 72 but is
symmetrical about the longitudinal central axis L of the blank 60.
Page 17
CA 02515934 2005-08-15
(OOG9~ Secondary score lines 88, 90, which are equidistaxxt from and parallel
to the main
score line 72, are shown in FIG. 8. In the disclosed embodiment, these
secondary score
lines 88, 90 era spaced about 3 inches to either side of the main score line
72. Since the
stepping of the plies 54, 56, 5$ Longitudinally offsets the front and hack
plies (FIGS- 7 to
9), the relative upward folding of the back plies causes the folds above score
line 72 to
fore: si:ortex daps tha~~ front side ply i?a; s bo:low score l:nc ?2. h.1 the
disalas~:d
embodiment, the offset of tl~e front side to back side plies caused by the
stepping ufthe
plies 52 is about 1 inch. Thereby, when the secondary scone Jxnes 88, 90 are
forrrted, the
portion of the front side plies below score lane 90 has a greater length than
the back side
plies above score line 88, as would be understood with reference to FIG. 7.
The score lines
72, $ 8, 90 are all shown iti FTG. 7 far purposes of explanation. It should be
understood that
tlxe poly liner 10 will receive a crease along the scare line 88, as well as
the paper plies that
envelop it.
(0070 Per other embodiments, the satchel bottom is dinoiemsioned as shown in
FIG. 8.
L?iznension "A" represents the slit length corresponding to slits 84.
Dimension "A" is
dependent on the satchel bottom depth drown as dimension "C" as given by the
equation
A ~ (C + 118 inch) - (C x 13116), which reduces to A = 5/16 C. Dimension "B"
is the
distance from the bag edge to the edgy of the izrnermost paper ply. Dimensian
"B" is 1/8
inch greater than the satchel bottom depth "C." The patch length is
represented by
dimension "D." Dimension "D" is given by the equation D = (W - C) + 1 inch.,
wherein
"W" is the width of the bag from one edge to the other. Dimension "D" includes
X inch for
a cuff, shown as dimension "F." Dimension "E" is the distance from the apex to
the slit as
shown in FIG. 8 and is equal to dimension "A."
Page 1$
CA 02515934 2005-08-15
[pa71 ] The next stage in the formation of the satchel bottom 70 is
illustrated in FIG. 9. An
application of adhesive 92 is shown with stippling in the geometric zones of
adhesion on
the papers plies 54, 56, 58 created by the slitting 84, 85 and the folding of
the plies about
the main score line 72. As stated, this folding creates the diagonal folds 74,
76, 7S, 80
whereby a cerr effective series of ~eometz-ically expnsed opposable surface
areas are
GrL2ted, u110';~~~Ti~ ~OX StCGT:~ C~IIt~iGt fOz7d112b ~fit~lr ld1:e51Ye Q~-
j0U72J This farrx~ation or pattern alsa allows for the free non-adhesive
retez~tioz~ ofthc
folded poly liner 10, as shown at the brob,ett-away triangular shaped folded
pottioxts of the
paper plies (F1G_ 7) that cover parts l0a and lob of the poly liner. It will
be seen that the
poly liner 10 above score line 72 assumes a generally tzapezoidal shape
bounded by the
score line 72, diagonal folds 74, 76, and a portion of the innermost paper ply
58, generally
along the edge 94 extending between the diagonal folds 74, 76_
[0073) The adhesive 92 preferably comprises a hot melt glue and is applied in
four zones
as shown in FIG_ 9, so as not to contact the poly liner 10. The cones are
located outwardly
a~the secondary fold lines 88, 90 and extend to the diagonal fold lines 74,
76, 78, 80. Flaps
116, 118 formed by slitting paper plies 54 along $4 have adhesive at both flap
ends, t5ut no
adhesive is applied along the length of the flap.
[00T4J For bags having an easy opening feature, an opener strip 120 is placed
against the
diagonally folded plies 52 of the satchel bottom before the flaps 116,118 are
folded i nward_
This is so that the opener strip 120 lies within the folded flaps 116, 118 of
the satchel
bottonr~ 70.
~007~] The back side plies above score line 72, as shown iii )FIGS. 8 and 9,
arc rotated or
folded abort secondary scare line 88. This step folds the back side paper
plies 54, 56, 5$
generally onto themselves which also rotates and secures the poly liner along
the fold line
1?age 19
CA 02515934 2005-08-15
8$ theretu0.der. At this stage, the inner poly liner 10 is folded along
diagonal bends 74, 76
and at the cxease formed along secondary fold line 58.
[QOlfi] The ply flaps of the front side of the paper plies S4, 56, 58 about
the secondary fold
line 90, thereby rotates the adhesive 92 to overlie the paper plies >4, 5b, 58
of the back side
of ti~~ bag 60. T7.~is step also Lolds the respectiv:, purt:ons of the front
side flaps ~~n,o
themselves. Each of tlae surfaces wale r~ferenee nu.~:~z~i ~~= indicwte t~~e
exposed bottolr
surfaces of the satchel bottom which are con~.prised of the outez~ paper ply
54.
[QQ77] 'fv fuzther reinforce tlz.e satchel bottom, a patch 122 may be
adhesively fixed to the
outside of the bottom of the bag as shown in FIG. 10. The patch zztay be a
single ply of
kraft paper adhesively fixed to the exterior of the satchel bottom, or may be
of other
suitably strong material to reinforce the satchel bottom 70 . Reinforcement
may be
desirable because of foreseeable rough handling or to compensate for the lack
of adhesive
on the flaps when combined with an easy opening feature. The patch 122 is
placed on the
outside of the folded. flaps to reinforce the satchel bottom. The patch is
secured by
adhesive 124 placed ixr zones along the long edges of the patch. The
embodiment shown
in FIC'r. 10 has the adhesive 124 oriented in strips located on either side of
the patch's long
axis.
[007$] It may be desirable to have an easy-opening feature on the bag. In this
embodiment,
the patch has a cuff 126 located at one of its lateral side edges. The cuff
1Z6 is defined by
a pair of slits 128, 130 in the patch approximately 1 inch long. The opener
strip 120 placed
laterally under the flaps 116, 118 of the satchel bottom extends to cooperate
with the cuff
12~ area of the patch 122. The cuff area 126 is designed to allow a user to
lift the cuff away
from the satchel bottom 70 and grasp the opener strip 120 to pull and tear
open the bottom
of the bag. The opetxer strip 120 may be made of string, plastic or other
suitable material.
Page 20
CA 02515934 2005-08-15
The opener strip 120 operates to tear the flaps 116, 118 of the satchel bottom
and the patch
122 when pulled by a user to open the bag.
[0079] Upon the drying of the adhesive 92, the satchel bottom 70 is completed.
The steps
for forming the tube blank GO are thereby also completccl. The znulti-ply
plastic lined bag
with satchel bottom 50 is now in a flat blank stackable f~nz~. ready for
shipment to the
mant:fac4tu-er, packer, or tlx~ like, for f ping witb a p_ro~iuct.
[0080] When the bag 10 is ready for fillizag, the satchel bottom 70 is
unfolded to form a flat
rectangular bottom shape as illustrated it1 FICr. 5, whereby the open mouth
top is positioned
for the introduction of a product, typically a dry granulated powder, such as
milk grattules,
or the like. The short sides of the rectangular bottom are the overlapped
edges of the paper
plies, generally dEnoted at 102, 104 in FIG. 5. The longer edges of the
rectangular bottom
are denoted at 106, 108, which are the fold lines of the paper plies along
secondary score
liztes 88, 90, respectively. At each turner of the bag, adjacent the short
edges 102, 104, a
triangle is formed with the diagonal fold lines, as at 110, 112, noted in
F'IG. 5. The lateral
edge of the bag 50 will taper to meet the intersection of the diagonal bend
lines 110, 1 I2,
shown. at one side of the bag ibr illustration, at reference numeral 114 in
FIG. 5. The
mirror image of course is formed on the opposite side of the bag, not shown,
Page 21
