Note: Descriptions are shown in the official language in which they were submitted.
CA 02437290 2003-08-13
POM PT ONE STEP WIT1~ A CROSS DIRECTIONAL. RIPPING-STRIP
FIELD OF THE INVENTION
The present invention relates generally to the field c~f the mufti-wall paper
bag
industry and more particularly to the production of a Paste Open Mouth style
bag with
a Pinched Top, embracing an inserted liner.
EACKGROUND
In the mufti-wall paper bag industry, so far, nabody was able to provide an
easy and
secure opening feature in a POM style bag with a pinched top (PT) in a 2 or 3
paper
ply bag with a poly inserted finer.
On the known version of POM PT style bags, the bottom is covered with a patch.
Customers require a special sealer which cuts fihe liner just above the seal
to prevent
the liner from being caught in the flap at the top closure. The access to the
liner is
thus difficult. Even when an easy opening feature is implemented, the end user
usually uses a knife to open the bag, resulting in potential damage to the bag
and
risk of injury.
The SOM liner, the most traditional bag, offers easy access to the liner.
During
manufacturing, the liner is manually inserted and sealed. The bag is closed
with the
help of a sewing thread. The manufacturing process is labour intensive, has a
high
lead time and creates risk of injury during the manual insertion. The final
product has
a poor standing-ability, exhibits a high risk of contamination during the
filling process
and is not compatible with the PT closing equipment.
The SOS liner is very similar to the SOM finer. However, it stands better on a
flat
surface. It still exhibits similar limitations of the SOM liner.
The SOS PT bag (or commercially known as a "WEBB bag") is a very expensive bag
and is only offered by a limited amount of suppliers. It has a square bottom
and is
compatible with the pinch closure equipment on the tap. The bag provides a
good
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pallet display, but still has limitations. The inner liner cannot be separated
from the
paper bag and hence both cannot be recycled. It is also not possible to seal
the liner
fully hermetically.
A very popular version in industry is the PB011/I bag. Its top closure is
pinch type and
is therefor adapted to the same closing eguipment. Again the liner cannot be
separated and it has a poor standing-ability.
SUMMARY OF THE INVENTION
An object of the invention is to provide a POM PT bag that overcomes the above
mentioned drawbacks.
Another object of the invention is to provide such a POM PT bag having an
inserted
liner.
Another object of the invention is to provide such a POM PT bag having a top
closure
that can be folded above a customer seal in order for an inner liner to be
fully
independent from the bag after the bag is opened with the help of a ripping-
strip
(easy opening feature}.
Another object of the invention is to provide such a POM PT bag wherein the
Liner is
not trapped in an upper flap of the bag in order for the bag to be fully
recyclable.
Another object of the invention is to provide such a POM PT bag in which a
liner can
be removed from the bag far hygienic reasons (as for the food and
pharmaceutical
industries).
According to the present invention there is provided a POIVI PT bag comprising
adhesive material applied on a ply step of the bag, a rip~>ing-strip and a non
adhesive
coated area embedding the ripping-strip. The bottom oi~ the bag comprises a
folded
flat bottom. The bag holds an inserted liner.
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BRIEF DESCRIPTION OF THE DRAV~fINGS
These and other objects and advantages of the invention will become apparent
upon
reading the detailed description and upon referring to the drawings in which;
Figure 1 is a schematic perspective top view of a POM PT bag according to the
present invention.
Figure 2 is a schematic partial perspective top view of a POM PT bag prior to
the
filling according to the present invention.
Figure 3 is a schematic partial perspective top view of a closed POM PT bag
according to the present invention.
Figure 4 is a schematic perspective front view of a POM PT bag showing the top
and
the bottom closures according to the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION
Referring to figures 1 to 4, there is shown a POM PT style multi-wall paper
bag
having an outer ply 1. The number of plies can varies through the field of
application
and the bag is preferably made of paper. The bag comprises a pasted open mouth
and has a pinched top closure. The bag has a flat bottom closure 2 in order
for the
bag to stand in an upright position on a flat surface such as a conveyor. The
filled
bag preferably has a triangular profile converging from fihe bottom closure 2
to a top
closure 12 of the bag when in standing position.
The top closure 12 of the bag has an upper flap 10 that can be folded, along a
guideline axis 5, on the outer ply 1 for closing the open mouth. A coated
adhesive 6
is located on the upper flap 10. Preferably, the coated adhesive 6 applied on
the
upper flap 10 is a strip of hot melt glue. The hot melt glue has to be
reactivated
before closure of the bag to ensure a tight seal. Other adhesive coating
material, or
tape, can also be used for the same purpose. For example, a two-faces adhesive
tape can be applied on the upper flap 10. An advantage of tile adhesive tape
over
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the hot melted glue is that it does not require from a user to have a special
closing
equipment to close the bag. A soluble glue can also be used to facilitate
recycling of
the paper bag.
A ripping-strip 8 is located within an area 7. The area 7 is located between
the
adhesive coating material 6 on the upper flap 10 and the open mouth of the
bag. This
area 7 is kept free of adhesive material and hence forms fihe non coated area
7. The
ripping-strip 8 can be made of any synthetic material. For easy gripping by a
user,
the ripping-strip 8 has a portion 11 exceeding an edge of the bag. This
portion 11 of
the ripping-strip 8 provides adequate length for the customer to get hold of
it. The
bag preferably has perforations 9 on both sides along the ripping-strip 8 to
ease the
opening process.
An inner liner 3 is inserted within the bag. The liner 3 is preferably made of
polyethylene. The open mouth of the liner 3 is preferably located near the
open
rnouth of the bag.
During the manufacturing process of the bag, the liner 3 is mechanically
inserted into
the bag in form of a continuous poly tubing. The bottom of this poly tubing is
heat
sealed during the manufacturing process, forming a liner. flue points between
the
bag and the liner 3 secured the bottom of the liner 3 to the interior bottom
of the bag.
The liner 3 can be completely removed from the bag after the pinched top
closure is
ripped open by the ripping-strip 8.
At a user's filling facility, for example, a product is filled in the finer 3.
Then, using a
conventional sealer, the inner Liner 3 is sealed through the paper bag to form
the
customer seal 4. The adhesive coating material 6 is heated and the upper flap
10 is
folded just above the customer seal 4 of the liner. The sealing of the open
mouth of
the liner 3 is preferably done by heating elements heating the liner 3 through
the
paper bag. The heat is transferred to the finer 3 which seals itself. It is
important to
note that during the sealing process, the liner 3 does not react with the
paper bag
and does not adhere to it. To remove the inner liner 3 once the upper flap 10
is
folded and sealed on the outer ply 1, the user has to grab the ripping-strip 8
by the
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exceeding portion 11 and tear it off. Then, the user can remove the liner 3
tram the
bag or leave it there. This is a bag in a bag concept.
It is recommended to use high performance paper in order to provide a strong
flap at
the closure. It is also possible to position a mid-step with the mid ply in a
~ paper ply
bag design. The mid step is designed in such a way that the finer would stilt
be
positioned above the folding line 5. This mid step can :stiffen and reinforce
the flap
10.
The bag is also compatible with a sealing head where the liner is trimmed just
above
the seal. The stepping pattern could be traditional or the one step as
described in this
patent.
In the case of a 3 paper ply bag, the mid ply could be stepped at mid position
of the
outer ply step. In this case it could be possible to add two slits at the
start to help the
opening.
The POM PT style bag of the present invention has the following advantages:
- Easy access to the inner liner 3 (poly tubing), easy, secure and fast
opening;
- The paper bag and the poly bag are recyclable;
- Compatible with a conventional sealer where the liner is heat sealed through
the
paper bag at the top. The conventional sealer cannot cut the finer above the
seal;
- This bag style offers a good pallet display;
- Stands very well on conveyors or on the floor;
- Minimum labour required for the filling process;
- Very hygienic bag as there is a minimal handling. The bag and the process
were
designed in order to minimize the potential product contamination. This bag is
compatible with the actual requirements of the food industry; and
- The closing is strong and secure from a food safety perspective.
The POM PT bag can be made of the following material:>:
- Inner liner 3: Poly tubing (should be strong enough to carry the material by
itself);
- Inner ply of the paper bag: Multi-wall kraft paper (high performance paper
is
recommended);
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- Mid ply of the paper bag (optional): Mufti-wall kraft paper (high
performance
paper is recommended);
- Outer ply of the paper bag: Mufti-wall kraft paper (printed or plain; high
performance paper is recommended); and
- Closure components: Hat melt glue (regular or ~~oluble) or two sided auto-
adhesive tape, ripping-strip made of synthetic material.
While embodiments of this invention have been illustrated in the accompanying
drawings and described above, it will be evident to those skilled in the art
that
changes and modifications may be made therein without departing from the
essence
of this invention.
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