U.S. patent application number 09/967302 was filed with the patent office on 2002-05-02 for laminated paper stocks and flexible packaging made therefrom.
Invention is credited to Gatewood, Steven J., Knauf, Gary H..
Application Number | 20020050119 09/967302 |
Document ID | / |
Family ID | 22891853 |
Filed Date | 2002-05-02 |
United States Patent
Application |
20020050119 |
Kind Code |
A1 |
Gatewood, Steven J. ; et
al. |
May 2, 2002 |
Laminated paper stocks and flexible packaging made therefrom
Abstract
A laminated paper stock made of at least one biaxially oriented
polymeric film, an adhesive material and a paper substrate. A
flexible packaging for wrapping paper comprised on the laminated
paper stock is also provided as well as related methods of
manufacture.
Inventors: |
Gatewood, Steven J.; (Green
Bay, WI) ; Knauf, Gary H.; (Bear Creek, WI) |
Correspondence
Address: |
Dara L. Onofrio, Esq.
c/o ONOFRIO LAW
233 Broadway - Suite 2702
New York
NY
10279-2799
US
|
Family ID: |
22891853 |
Appl. No.: |
09/967302 |
Filed: |
September 28, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60236988 |
Sep 29, 2000 |
|
|
|
Current U.S.
Class: |
53/396 |
Current CPC
Class: |
B32B 27/10 20130101;
B32B 7/12 20130101 |
Class at
Publication: |
53/396 |
International
Class: |
B65B 001/00 |
Claims
What is claimed is:
1. A laminated paper stock comprised of: at least one biaxially
oriented polymeric film; an adhesive material; and a paper
substrate.
2. The paper stock according to claim 1, wherein said biaxially
oriented polymeric film is selected from the group consisting of
polypropylene, polyester, nylon, polystyrene and polyethylene.
3. The paper stock according to claim 2, wherein said polyethene is
selected from the group consisting of low density polyethylene
(LDPE), linear low density polyethylene (LLDPE), metallocene low
density polyethylene (m-LDPE) and high density polyethylene
(HDPE).
4. The paper stock according to claim 1, wherein said adhesive
material is selected from the group consisting of low density
polyethylene (LDPE), linear low density polyethylene (LLDPE),
metallocene low density polyethylene (m-LDPE), high density
polyethylene (HDPE), polypropylene (PP), ethylene vinyl acetate
(EVA), ethylene methyl acrylate (EMA), ethylene acrylic acid (EAA),
polyethylene terepthalate (PET) and lonomer.
5. The paper stock according to claim 1 wherein said polymeric film
surface is printed.
6. The paper stock according to claim 1 wherein said paper surface
is printed.
7. The paper stock according to claim 1, wherein said paper
substrate is selected from the group consisting of cellulosic and
synthetic materials.
8. The paper stock according to claim 7, wherein said paper
substrate is bleached paper or paperboard.
9. The paper stock according to claim 1, comprising an additional
biaxially oriented polymeric film placed on either the uncoated
paper substrate surface or on said film surface or both.
10. A flexible packaging for wrapping paper comprised of a
laminated paper stock made of at least one biaxially oriented
polymeric film adhered to a paper substrate.
11. The packaging according to claim 10, wherein said biaxially
oriented polymeric film is selected from the group consisting of
polypropylene, polyester, nylon, polystyrene and polyethylene.
12. The packaging according to claim 11, wherein said polyethylene
is selected from the group consisting of low density polyethylene
(LDPE), linear low density polyethylene (LLDPE), metallocene low
density polyethylene (m-LDPE) and high density polyethylene
(HDPE).
13. The packaging according to claim 10, wherein said adhesive
material is selected from the group consisting of low density
polyethylene (LDPE), linear low density polyethylene (LLDPE),
metallocene low density polyethylene (m-LDPE), high density
polyethylene (HDPE), polypropylene (PP), ethylene vinyl acetate
(EVA), ethylene methyl acrylate (EMA), ethylene acrylic acid (EAA),
polyethylene terepthalate (PET) and lonomer.
14. The packaging according to claim 10 wherein said polymeric film
surface is printed.
15. The packaging according to claim 10 wherein said paper surface
is printed.
16.. The packaging according to claim 10, wherein said paper
substrate is selected from the group consisting of cellulosic and
synthetic materials.
17. A method of making a laminated paper stock comprising the steps
of: providing at least one biaxially oriented polymeric film; and
adhering said film to a paper substrate.
18. The method according to claim 17, wherein said film is selected
from the group consisting of polypropylene, polyester, nylon,
polystyrene and polyethylene.
19. The method according to claim 18, wherein said polyethene is
selected from the group consisting of low density polyethylene
(LDPE), linear low density polyethylene (LLDPE), metallocene low
density polyethylene (m-LDPE) and high density polyethylene
(HDPE).
20. The method according to claim 17, wherein said film is adhered
to said paper substrate by an adhesive material selected from the
group consisting of low density polyethylene (LDPE), linear low
density polyethylene (LLDPE), metallocene low density polyethylene
(m-LDPE) and high density polyethylene (HDPE), polypropylene (PP),
ethylene vinyl acetate (EVA), ethylene methyl acrylate (EMA),
ethylene acrylic acid (EAA), polyethylene terepthalate (PET) and
lonomer.
21. The method according to claim 17 comprising the further step of
treating said film surface to enhance printability.
22. The method according to claim 17 comprising the further step of
treating said film surface to enhance processability.
23. The method according to claim 17, wherein said paper substrate
is selected from the group consisting of cellulosic and synthetic
materials.
24. A method of making a flexible package for wrapping paper
comprising the steps of: providing a laminated paper stock made of
at least one biaxially oriented polymeric film adhered to a paper
substrate; and forming said package from said stock.
Description
[0001] This application claims the benefit of U.S. provisional
application Serial No. 60/236,988 filed on Sep. 29, 2000, which is
incorporated herein by reference.
FIELD OF INVENTION
[0002] The present invention relates to laminated paper stocks. In
particular, the paper stocks are made into flexible packaging
having enhanced printability and processability properties.
BACKGROUND OF THE INVENTION
[0003] The growth of the retail market for selling cut size paper
has created new demands for distribution and delivery of ream paper
to individual customers. The demands for retail sales of ream paper
includes stronger packaging to withstand the rigors of handling
individual reams of paper and improved graphics and appeal of the
package to attract the customer and to differentiate the product
among the many packages of ream paper on the store shelves.
[0004] A number of variations of traditional ream packaging
alternatives have been developed to achieve these goals. These
included using higher strength paper and laminating resins, all
film structures, film laminations and heavier gauge papers for
improved strength and coated papers, specialty printing inks and
film laminations for improved visual appeal. However, these film
structures were limited by the lack of stiffness, poor
machinability and relatively high cost.
[0005] In general, the prior art has shown laminated structures
comprised of polymeric film and paper for a variety of
applications. Representative patents include U.S. Pat. No.
6,030,759 to Gula et al.; U.S. Pat. No. 6,004,732 to Alyward et
al.; U.S. Pat. No. 5,994,045 to Bourdelais et al.; U.S. Pat. No.
5,968,695 to Gula et al.; and U.S. Pat. No. 5,888,643 to Aylward et
al. which all disclose specialty laminates comprising
paper/polypropylene laminates in combination with other materials
or layers, useful as photographic elements.
[0006] U.S. Pat. No. ,891,580 to Fricke et al. discloses a method
for adhering biaxially oriented polypropylene to paper substrates
with certain polyurethane adhesives.
[0007] U.S. Pat. No. 3,862,869 to Peterson et al. discloses the
preparation of a tear-resistant laminate by adhesively bonding
biaxially oriented polypropylene to a paper substrate employing a
polyolefin melt adhesive.
[0008] U.S. Pat. No. 3,775,549 to Matsuda et al. discloses an
insulation material for electric power cables comprising biaxially
oriented polypropylene laminated to paper with a polyolefin melt
adhesive.
[0009] However, unlike the known art, the invention provides a
laminated paper stock, for flexible packaging, made of at least one
biaxially oriented polymeric film, an adhesive material and a paper
substrate. Paper film lamination provides a good combination of
ease of runnability on packaging equipment designed and used for
traditional paper based ream packaging materials and the improved
strength and graphics appeal afforded by the film structures.
[0010] Thus, it is a broad objective of the invention to provide
flexible packaging having enhanced printability and processability
properties.
[0011] Another object of the invention is to provide a ream wrap
substrate that performs superior to other paper/film packaging
structures.
[0012] Another specific object of the invention is to provide a
ream wrap that processes well on existing ream packaging equipment
at costs comparable to paper based ream wrap substrates without the
need for significant machine adjustments or modifications.
[0013] Another specific object of the invention is to provide a
ream wrap package having excellent strength and superior
runnability.
SUMMARY OF THE INVENTION
[0014] In the present invention, these purposes, as well as others
which will be apparent, are achieved generally by providing a
laminated paper stock comprised at least one biaxially oriented
polymeric film, an adhesive material and a paper substrate. These
paper stocks are preferably used to produce flexible packaging for
wrapping paper.
[0015] Other objects, features and advantages of the present
invention will be apparent when the detailed description of the
preferred embodiments of the invention are considered which should
be construed in an illustrative and not limiting sense as
follows:
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0016] In accordance with the present invention a laminated paper
stock comprised of at least one biaxially oriented polymeric film;
an adhesive material; and a paper substrate is provided.
[0017] The biaxially oriented polymeric film is selected from the
group consisting of polypropylene, polyester, nylon, polystyrene
and polyethylene. Prefereably polyethene is used and is selected
from the group consisting of low density polyethylene (LDPE),
linear low density polyethylene (LLDPE), metallocene low density
polyethylene (m-LDPE) and high density polyethylene (HDPE). In a
preferred embodiment the polymeric film is a biaxially oriented
high density polyethylene.
[0018] The polymeric film is laminated to the paper substrate using
an adhesive resin. The adhesive material used in the invention are
selected from the group consisting of low density polyethylene
(LDPE), linear low density polyethylene (LLDPE), metallocene low
density polyethylene (m-LDPE), high density polyethylene (HDPE),
polypropylene (PP), ethylene vinyl acetate (EVA), ethylene methyl
acrylate (EMA), ethylene acrylic acid (EAA), polyethylene
terepthalate (PET) and lonomer.
[0019] The polymeric film surface or the paper surface of the
substrate can be printed on.
[0020] The paper substrate is used in the invention is selected
from the group consisting of cellulosic and synthetic materials. In
a preferred embodiment the paper substrate is bleached paper or
paperboard.
[0021] It is also within the scope of the invention to add
additional biaxially oriented polymeric films on either the
uncoated paper substrate surface or on the film surface or both.
Multiple film layers are also encompassed by the invention.
[0022] The laminated paper stock is preferably used to make
flexible packaging for wrapping paper. The laminated stocks provide
good moisture barrier properties for ream wrap applications.
[0023] The invention also provides a method of making a laminated
paper stock comprising the steps of providing at least one
biaxially oriented polymeric film; and adhering the film to a paper
substrate.
[0024] The film is selected from the group consisting of
polypropylene, polyester, nylon, polystyrene and polyethylene.
Preferably, the polymeric film is stretched in both the MD and CD
direction prior to being laminated to the paper substrate. This
increases the strength properties of the film and resulting
laminate.
[0025] Polyethene is a preferred material used. As previously
described, the types of polyethylene used are selected from the
group consisting of low density polyethylene (LDPE), linear low
density polyethylene (LLDPE), metallocene low density polyethylene
(m-LDPE) and high density polyethylene (HDPE).
[0026] The film is adhered to the paper substrate by an adhesive
material selected from the group consisting of low density
polyethylene (LDPE), linear low density polyethylene (LLDPE),
metallocene low density polyethylene (m-LDPE) and high density
polyethylene (HDPE), polypropylene (PP), ethylene vinyl acetate
(EVA), ethylene methyl acrylate (EMA), ethylene acrylic acid (EAA),
polyethylene terepthalate (PET) and lonomer.
[0027] The resulting laminate formed can be further treated to
enhance printability and/or to enhance processability. Such
treatments include but are not limited to corona treatments and
slip treatments.
[0028] The invention further provides a method of making a flexible
package for wrapping paper. The laminated paper stock made of at
least one biaxially oriented polymeric film is adhered to a paper
substrate and then formed into a package.
[0029] In general, the invention provides a flexible package for
wrapping paper made by laminating a clear polymer film to a paper
substrate. In a preferred embodiment, the paper is preferably 15-60
lb/3000 ft.sup.2 of a white paper. The paper provides an excellent
substrate for printing on or, in the case of reverse printed film,
a background that highlights and showcases the graphic print
design. The paper also provides the stiffness and bottom surface
characteristics that allows this structure to process well on
production paper packaging equipment.
[0030] An extrudable or adhesive coating is applied to the paper
and film to laminate the clear or reverse printed overlaminate film
to the paper. The film protects the buried printed surface and adds
considerable gloss and visual appeal to the finished package. The
film also increases the strength of the finished product to make it
ideally suited for retail sales environment.
[0031] The preferred film for this invention is a biaxially
oriented high density polyethylene film with optional specialty
treatments on the inside and outside surfaces. Typical film
thickness can range from 30 gauge (0.00030" thickness) to 2 mil
(0.002") depending on performance requirements.
[0032] Numerous paper options may be used to provide unique
functional characteristics. These may include brightness
adjustments and various hold out coatings for excellent printing
characteristics.
[0033] Paper and lamination characteristics may be manipulated to
improve the physical properties of the finished structure. When the
film is laminated to the paper, the film is limited in its ability
to stretch and absorb the energy to maintain the integrity of the
package. Options to improve the physical properties, include, but
are not limited to, changing the furnish of the paper, modifying
the internal bond of the paper, adjusting the stretch
characteristics of the paper, increasing moisture level of the
paper, process/machine conditions during lamination or laminating
resins or adhesives to modify the bond between the paper and
film.
[0034] The invention packaging provides improved strength for the
retail ream paper market. Traditional paper-paper laminated reams
exhibit poor strength performance resulting in likely significant
ream wrap damage and subsequent returns from retail stores.
[0035] Puncture test results, which are a predictive test for
durability in a retail environment, showed surprisingly good
results with the invention packaging, in particular with packaging
including a biaxially oriented high density polyethylene film.
These results were far superior to typical low density polyethylene
structures which have lower strength characteristics and behave
poorer in the drop tests.
[0036] Glue tests conducted on the invention packaging showed
superior glueability to the paper/film structure. In particular the
embodiments using the biaxially oriented high density polyethylene
showed excellent glueability to the paper substrates.
[0037] The laminated structure of the invention performs with ease
on equipment designed for traditional paper/paper laminated ream
wraps. This package feeds into the packaging equipment especially
well and seals remarkably well using hot melt glues for sealing
traditional paper ream wraps. Additionally, the surface
characteristics of this structure allows the material to run at
high speed on commercial packaging equipment with no or few machine
adjustments. Other known paper/film structures require special
glues and don't run as well or as fast on their equipment as
traditional paper/paper ream wraps.
[0038] The advantage of the invention paper stock is in the
provision of a ream wrap product having excellent strength and
superior runnability. The strength of the wrap is best
characterized by the drop test performance. The drop test was
developed to simulate the durability and performance of the wrapper
in the retail distribution and sales environment. This is a semi
destructive test on the packaged paper.
[0039] The attributes of the invention packaging contribute to the
excellent runnability and appearance of the wrapper including print
appearance, tightness of wrapped ream, glueability and durability
of the glued flaps, material handling on the packaging line,
packaging run speed, and others.
[0040] The following examples will serve to illustrate the
invention. These examples are merely representative and are not
inclusive of all the possible embodiments of the invention.
EXAMPLE 1
[0041] Small sample rolls of the laminated paper stock of the
invention were tested for puncture resistance. The test was
conducted as a first level test to predict performance in retail
sales environment. Puncture test results showed surprisingly good
performance with the laminated paper stocks of the invention, in
particular with the biaxially oriented high density polyethylene
film embodiment.
EXAMPLE 2
[0042] Biaxially oriented high density polyethylene film was
laminated to paper in accordance with the invention and drop tested
using the procedure described below.
[0043] Procedure
[0044] The drop test uses an MTS Shock Test Machine to simulate
dropping a ream of paper 18 inches. Reams were conditioned indoors
for 8 hours before testing. They are then mounted on the machine at
an angle so one corner of the ream will impact before the rest of
the ream. Impact is at an 8.degree. angle. The angle of impact is
critical to drop performance and the Shock Test Machine accurately
reproduces this angle for each ream. The results +/-5 for lots of
100 dropped reams are considered significant.
[0045] Results
[0046] The pallet of paper arrived in excellent shape and no reams
were torn when removed from the cases. When 100 of the reams were
dropped none of them ripped. None of the reams had glue issues
either when removed from the cases or after dropping.
EXAMPLE 3
[0047] Laminated ream wrap packages were made in accordance with
the invention. Two different glues were used to make the packages
and were tested. Sample A was made with a hot melt glue available
from National Starch (34-2557 EVA) and Sample B was made with a hot
melt glue available from HB Fuller (9255).
[0048] The samples were subjected to the drop test as described in
Example 2.
[0049] Results
[0050] When 99 reams of Sample A were dropped none of them tore. On
41 of the reams, however, the glue on the top flap failed and the
flap opened. On one other ream the glue on the bottom flap failed.
The remaining 57 reams survived the drop without failure. All
adhesive failures resulted from the hot melt glue not adhering to
the film surface. None of the failures gave any evidence of fiber
tear. Sample B--none of the 99 dropped reams tore or had glue
failure.
EXAMPLE 4
[0051] Laminated ream wrap packages were made in accordance with
the invention. Drop test performance and end flap seal integrity
were tested on Samples A and B which are described in Example
3.
[0052] The samples were subjected to the drop test as described in
Example 2. The samples were also subjected to a Glue Peel Test.
[0053] Glue Peel Test Procedure
[0054] After overnight conditioning, the end flaps of the reams
were peeled open. Peeling was done carefully so that the fiber tear
was minimized. The length of the glue bead which gave fiber tear
was measured and compared to the total length of the glue bead
(rounded to the nearest 10%). Fiber tear of 50% or greater is rated
an acceptable seal.
[0055] Results
[0056] The pallet of paper arrived in excellent shape. No damage to
the cases or reams was observed. Before testing, cases were
conditioned overnight at standard TAPPI conditions.
[0057] One hundred reams of each sample were dropped using the drop
test procedure described. None of the reams of Sample A ripped, but
one end flap popped open on 7 of the reams. For 6 of these 7 reams
it was the top flap which opened.
[0058] The rip performance of reams of Sample B was equally good
(no tears) and none of the end flaps opened when dropped. A perfect
score in the drop test correlates well with rugged performance in
the retail market.
[0059] The glue performance of each sample was examined. It was
observed that the glue used in Sample B gave over twice the amount
of fiber tear as the glue used in Sample A.
[0060] The foregoing description of various and preferred
embodiments of the present invention has been provided for purpose
of illustration only, and it is understood that numerous
modifications, variations and alterations may be made without
departing from the scope and spirit of the invention as defined in
the appended claims hereto.
* * * * *