U.S. patent application number 09/820562 was filed with the patent office on 2001-08-16 for pressure-sensitive paper-plastic film laminate tape.
Invention is credited to Bloch, Gerald, Bloch, Gilbert, Finestone, Arnold B..
Application Number | 20010014392 09/820562 |
Document ID | / |
Family ID | 22982038 |
Filed Date | 2001-08-16 |
United States Patent
Application |
20010014392 |
Kind Code |
A1 |
Bloch, Gilbert ; et
al. |
August 16, 2001 |
Pressure-sensitive paper-plastic film laminate tape
Abstract
A pressure-sensitive laminate for adhering to various items. The
laminate includes a paper layer; a water-impermeable plastic film
layer having a first corona-discharge treated surface which is
adhesively laminated to the paper layer to form a paper-plastic
film laminate having first and second opposed outer surfaces; and
an exposed layer of a pressure-sensitive adhesive coating on one of
the first or second outer surfaces. The plastic film portion of the
laminate has a strength sufficient to allow the film to be stripped
in one piece from an item to which the laminate is adhered. The
laminate may, if desired, additionally have a layer of a release
agent upon an uncoated one of the first and second opposed outer
surfaces of the laminate. A preferred use for the laminate is as a
pressure-sensitive tape product.
Inventors: |
Bloch, Gilbert; (Palm Beach
Gardens, FL) ; Bloch, Gerald; (New York, NY) ;
Finestone, Arnold B.; (West Palm Beach, FL) |
Correspondence
Address: |
WINSTON & STRAWN
200 Park Avenue
New York
NY
10166-4193
US
|
Family ID: |
22982038 |
Appl. No.: |
09/820562 |
Filed: |
March 29, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09820562 |
Mar 29, 2001 |
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09258766 |
Feb 26, 1999 |
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6235386 |
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09258766 |
Feb 26, 1999 |
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08209405 |
Mar 14, 1994 |
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5962099 |
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08209405 |
Mar 14, 1994 |
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07975080 |
Nov 12, 1992 |
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Current U.S.
Class: |
428/352 ;
428/343; 428/354 |
Current CPC
Class: |
B32B 2307/7265 20130101;
B32B 27/10 20130101; C09J 2467/006 20130101; B32B 27/36 20130101;
B32B 2329/00 20130101; C09J 7/29 20180101; C09J 2423/006 20130101;
Y10T 428/2839 20150115; B32B 2405/00 20130101; Y10T 428/2848
20150115; Y10T 428/24959 20150115; B32B 2317/122 20130101; B32B
2310/14 20130101; Y10S 428/91 20130101; Y10T 428/14 20150115; B32B
2315/02 20130101; C09J 2301/302 20200801; C09J 2400/226 20130101;
Y10T 428/31895 20150401; B32B 2255/205 20130101; C09J 2400/163
20130101; Y10T 428/3188 20150401; B32B 27/32 20130101; B32B 2255/10
20130101; C09J 2400/283 20130101; Y10T 428/28 20150115; Y10T
428/2809 20150115; B32B 7/12 20130101 |
Class at
Publication: |
428/352 ;
428/343; 428/354 |
International
Class: |
B32B 007/12; B32B
015/04 |
Claims
What is claimed is:
1. A paper-plastic film laminate pressure sensitive sealing tape
product for adhering to various items in applications involving
taping and sealing and having sufficient body to permit dispensing
from a conventional pull and tear tape dispenser, the tape product
comprising: a paper layer; a water-impermeable plastic film layer
having a first corona-discharge treated surface, wherein the first
corona-discharge treated surface is adhesively laminated to the
paper layer to form a paper-plastic film laminate having first and
second opposed outer surfaces; and a layer of a pressure-sensitive
adhesive coating on one of said first and said second outer
surfaces, said pressure-sensitive adhesive coating exposed for use
in adhering the paper-plastic film laminate to the various items,
wherein the plastic film layer has a strength sufficient to allow
the film to be stripped in one piece from an item to which the
laminate is adhered.
2. The tape product of claim 1 further comprising a layer of a
release agent upon a remaining uncoated one of said first and said
second opposed outer surfaces.
3. The tape product of claim 2 wherein the release agent is a
silicone.
4. The tape product of claim 1 wherein the paper layer has a
thickness of about 3 to 6 mils and the plastic film layer has a
thickness of about 1 to 3 mils.
5. The tape product of claim 1 wherein the plastic film is an
oriented film comprising a polymer selected from the group
consisting of polypropylene, polyethylene and polyester, and
wherein the paper layer comprises Kraft paper.
6. The tape product of claim 1 wherein the first corona-discharge
treated surface is adhesively laminated to the paper layer by a
water-based adhesive.
7. The tape product of claim 6 wherein the water-based adhesive
includes an acrylic copolymer composition or a polyvinyl acetate
copolymer.
8. The tape product of claim 1 wherein the pressure-sensitive
adhesive includes a rubber, a vinyl rubber, a polyvinyl ether, a
polyvinylbutyral, a polyisobutylene or an acrylic.
9. The tape product of claim 1 wherein the pressure sensitive
adhesive is applied to the paper side of the laminate.
10. The tape product of claim 1 wherein the pressure sensitive
adhesive is applied to the film side of the laminate.
11. The tape product of claim 1 wherein an outer surface of the
plastic film layer is metallized.
12. The tape product of claim 1 wherein adhesive used to adhesively
laminate the first corona discharge treated surface to the paper
layer produces a stronger bond than the pressure sensitive adhesive
bond for allowing the paper-plastic film laminate to be stripped
off of an item in one piece.
13. The tape product of claim 1 wherein the outer surface of the
plastic film layer is corona discharge treated to render said
surface receptive to inks.
14. The tape product of claim 1 wherein the plastic film layer
comprises first and second opposed surfaces, wherein both said
first and said second plastic film layer surfaces are corona
discharge treated, wherein one said corona discharge surface is
adhesively laminated to said paper layer and wherein the remaining,
unlaminated surface of said plastic film layer is provided with a
layer of a release agent.
15. The tape product of claim 1 wherein said water impermeable
plastic film layer further comprises a second surface, opposed to
said first, corona-discharge treated surface, and wherein said
second surface is not corona discharge treated to prevent adhesion
to an adjacent overlapping layer of the tape product when said tape
product is wound on a pull and tear tape dispenser.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of application Ser. No.
09/258,766 filed Feb. 26, 1999, which is a continuation-in-part of
application Ser. No. 08/209,405 filed Mar. 14, 1994, now U.S. Pat.
No. 5,962,099, which is a continuation-in-part of application Ser.
No. 07/975,080 filed Jan. 9, 1992, now abandoned.
FIELD OF THE INVENTION
[0002] This invention relates generally to pressure-sensitive
sealing tapes, and more particularly to a paper-plastic film
laminate tape of exceptional strength and sufficient body to enable
the tape to be dispensed in a conventional tape dispenser
machine.
BACKGROUND ART
[0003] U.S. Pat. No. 4,351,877 to Williams discloses a sealing tape
for cartons, formed of a high-strength face ply of synthetic
plastic film material, laminated to a base ply of paper whose outer
surface is coated with a remoistenable adhesive. This tape is wound
into a roll and is dispensed from a standard Kraft paper
tape-dispensing machine which includes a water reservoir to moisten
the adhesive coating as the tape is advanced out of the
dispenser.
[0004] As pointed out in the Williams patent, though a sealing tape
formed from a thin film of synthetic plastic material is much
stronger than a Kraft paper tape, particularly if the film tape is
stretch-oriented, a roll of such film tape cannot be dispensed in a
Kraft paper tape-dispensing machine.
[0005] The reason for this is that the machine relies on the
longitudinal stiffness of the paper tape to unwind it from the roll
and force it through the outlet of the dispenser where the tape is
cut to a desired length. A thin plastic film is unable to be
dispensed lengthwise from a Kraft paper or a similar dispenser
machine because the flexible plastic film tape is inherently flabby
and lacks sufficient rigidity or stiffness for this purpose.
[0006] In order, therefore, to add sufficient rigidity to the tape
so that it can be properly dispensed, Williams laminates a paper
ply to the plastic film ply. To effect lamination of the paper ply
to the plastic ply, Williams uses a conventional glue for this
purpose. Should this glue be a hot melt adhesive of the type
ordinarily used to laminate paper to film, the resultant heat would
impair the orientation and strength of the film.
[0007] Our related U.S. Pat. Nos. 5,780,150 and 5,804,024 disclose
a paper-film laminate sealing tape having a base ply of oriented
film, cold-laminated by a water-based adhesive to a paper face ply
so that its orientation is maintained, the exposed surface of the
film base ply being coated with a remoistenable adhesive. The
present invention resides in a pressure-sensitive paper-plastic
film laminate tape which is applied to a surface to be sealed by
pressure as distinguished from a tape, as in Williams, and in our
earlier application in which the adhesive layer is
remoistenable.
SUMMARY OF THE INVENTION
[0008] In view of the foregoing, the main object of this invention
is to provide a paper-plastic film laminate for use in a
pressure-sensitive sealing tape that has exceptional strength and
sufficient body to enable the tape to be dispensed in a
conventional pull-and-tear tape dispenser.
[0009] More particularly an object of the invention is to provide a
tape of this laminate in which a plastic film ply,
biaxially-oriented to impart high-strength thereto, is cold
laminated to a paper ply by a water-based adhesive so, that
lamination is effected without heat that would impair the
orientation and strength of the plastic film ply.
[0010] A significant feature of a tape that includes a laminate in
accordance with the invention is that it is highly-resistant to
delamination and when stripped from a carton or other article, it
is removed therefrom in toto.
[0011] Briefly stated, these objects are attained in a laminate for
use in a pressure-sensitive tape for sealing cartons and for other
applications requiring a flexible material of exceptional strength
and of sufficient body so that the material in roll form may be
dispensed from a conventional pull-and-tear tape dispenser.
[0012] In a preferred embodiment, the invention is directed to a
pressure sensitive sealing tape product adapted to adhere to
various items in applications involving taping and sealing, and
having sufficient body to permit dispensing from a conventional
pull and tear tape dispenser. The tape product includes a laminate
made of a paper layer and a water-impermeable plastic film layer
having a first corona-discharge treated surface. In one embodiment,
the film layer of the laminate further includes a second surface
opposed to the first, corona-discharge treated surface. The second
surface is not corona-discharge treated, thus ensuring that
adjacent, overlapping layers of the laminate or tape do not adhere
to each other when wound on, e.g., a pull and tear dispenser.
[0013] Preferably, the first corona-discharge treated surface of
the plastic film layer is adhesively laminated to the paper layer
to form a paper-plastic film laminate having first and second
opposed outer surfaces. The laminate additionally includes a layer
of a pressure-sensitive adhesive coating on one of the first and
second outer surfaces. The pressure-sensitive adhesive coating is
exposed for use in adhering the paper-plastic film laminate to
various items. The plastic film layer has a sufficient strength to
allow the film to be stripped in one piece from an item to which
the laminate is adhered.
[0014] The laminate and tape products of the invention may
optionally further include a layer of a release agent located upon
a remaining uncoated outer surface. Preferred release agents for
use with the invention include the silicones.
[0015] In another embodiment of the invention the paper layer has a
thickness of from about 3 to about 6 mils, while the plastic film
layer has a thickness of from about 1 to about 3 mils.
[0016] Advantageously, the plastic film component of the pressure
sensitive sealing tape product is an oriented film comprising a
polymer selected from the group consisting of polypropylene,
polyethylene and polyester. Also, the paper layer preferably
comprises Kraft paper.
[0017] In a preferred embodiment, the first corona discharge
treated surface of the plastic film layer may be adhesively
laminated to the paper layer by a water-based adhesive. The
water-based adhesive may include, for example, an acrylic copolymer
composition or a polyvinyl acetate copolymer. The pressure
sensitive adhesive preferred for use with the invention may be
selected from among rubbers, vinyl rubbers, polyvinylethers,
polyvinylbutyrals, polyisobutylenes and acrylics. The pressure
sensitive adhesive may be applied to either the paper side or the
film side of the laminate. Additionally, if desired, an outer
surface of the plastic film layer may be metallized.
[0018] It is desirable, in forming the pressure sensitive laminate
of the present invention, to utilize an adhesive for laminating the
first corona discharge treated surface to the paper layer which
will produce a stronger bond than that produced by the pressure
sensitive adhesive to allow the paper-plastic film laminate to be
stripped off of an item to which it is adhered in one piece.
[0019] In another embodiment, the pressure sensitive laminate of
the invention comprises a paper layer having a first surface and a
second opposed surface; an oriented, water impermeable plastic film
having a first corona discharge treated surface and a second,
opposed surface, wherein the first corona discharge treated surface
is adhesively laminated to the first surface of the paper layer to
form a paper-plastic film laminate; an exposed layer of a
pressure-sensitive adhesive coating upon the second surface of the
paper layer; and a layer of a release agent located upon the
second, opposed surface of the plastic film. The plastic layer
incorporated in the above-described embodiment should have
sufficient strength to allow the film to be stripped in one piece
from an item to which the laminate is adhered.
[0020] In a further embodiment the invention is directed to a
pressure-sensitive sealing tape product for adhering to various
items in applications involving taping and sealing, wherein the
tape product includes the laminate in order to possess sufficient
body to permit dispensing it from a conventional pull and tear tape
dispenser. The tape product comprises one of the laminates
described herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] For a better understanding of the invention as well as other
objects and features thereof, reference is made to the detailed
description of the invention and the accompanying drawing
wherein:
[0022] FIG. 1 is a section taken through a preferred embodiment of
a sealing tape in accordance with the invention, the scale of the
tape being magnified;
[0023] FIG. 2 shows the tape in roll form loaded into a tape
dispenser; and
[0024] FIG. 3 shows the tape being stripped off a carton.
DETAILED DESCRIPTION OF THE INVENTION
[0025] The Tape:
[0026] Referring now to FIGS. 1 and 2, one preferred embodiment of
a sealing tape T in accordance with the invention includes a base
ply 10 formed of Kraft or other paper sheeting. Base ply 10 is cold
laminated by an adhesive layer 11 to a film ply 12 of
high-strength, synthetic plastic film, such as polyethylene.
Preferably the film is formed of a biaxially oriented material,
such as polypropylene or polyester (MYLAR). The inner surface of
film ply 12 is rendered wettable by a corona-discharge treatment to
enhance the energy at this surface so that it is receptive to
adhesives.
[0027] Coated on the exposed surface of paper base ply 10 is a
pressure-sensitive adhesive layer 13, so that the sealing tape can
be adhered to a carton, a package or other article. The
pressure-sensitive layer 13 may be any suitable pressure-sensitive
adhesive, such as rubber, vinyl rubber, polyvinylether,
polyvinylbutyral, polyisobutylene or acrylic. The tape acts to
close the flaps or joints of the carton or to carry out any other
conventional sealing function.
[0028] The plastic film face ply 12 is no greater than 3 mils in
thickness and is preferably about one mil in thickness; hence, by
itself, it lacks rigidity and body. The Kraft paper base ply 10 is
thicker, preferably being 2 or 3 mils thick, but no greater than
about 6 mills, thereby imparting a measure of stiffness and body to
the tape.
[0029] When film ply 12 is biaxially-oriented, it has exceptional
tensile strength, such orientation being effected by stretching the
film along both its transverse and horizontal axes to molecularly
orient the film structure. The strength of the thicker paper base
ply 10, per se, is not high, but the paper-film laminate has both
body and high strength, so that a roll of the tape can be used in a
conventional pull-and-tear tape dispenser.
[0030] Cold lamination of the plies is effected by a water-based
adhesive, preferably a polyacrylic copolymer composition having an
affinity both for the paper ply and the film ply. Because the
water-based adhesive is fluid at ambient temperature and is not a
hot melt adhesive; no heat is applied to the biaxially-oriented
film as it is being laminated to the paper ply. A water-based
adhesive, once cured, is not water soluble and is not
remoistenable.
[0031] It is important to bear in mind that a biaxially-oriented
film is heat-sensitive and that at elevated temperatures, the film
relaxes and loses its molecular orientation and strength. It is
known, for example, that when two sheets of biaxially-oriented
polyester film are seamed together, using an
ultrasonically-activated sealing bar for this purpose which creates
internal friction and heat within the film, this causes the
superposed films to soften and fuse. The resultant sealing line is
weak, and the sheets then tend to tear along this line. Cold
lamination is therefore essential to the present invention in order
to produce a tape paper- film laminate of high strength.
[0032] It is to be noted that a synthetic plastic film material,
such as polypropylene, is normally not receptive to adhesives,
especially water-based adhesives. Hence if one were to apply to the
surface of this film a water-based adhesive which is flowable at
ambient temperature or at a temperature somewhat above ambient but
not at the elevated temperature of a hot melt adhesive, the
adhesive will not be adsorbed by the film.
[0033] Essential to the invention is that the inner surface of the
film forming the face ply of the tape be treated so as to render it
wettable and hence receptive to adhesives. To this end, this
surface is subjected to a corona discharge treatment which enhances
the surface energy, as measured in dynes, and thereby renders the
surface wettable to allow for better bonding of the adhesive
applied thereto. The resultant bond both to the film and the paper
is so strong that the tape is highly resistant to delamination.
[0034] It is important that the film surface be subjected to
corona-discharge treatment shortly before adhesive is applied
thereto, for the effect of such treatment has a relatively short
duration. Thus if after such treatment, the film is stored for
several days or longer before being converted into a tape, the
wettability of the film surface will be greatly diminished.
[0035] Because of the pressure-sensitive adhesive layer 13 which
coats the outer surface of the paper base ply 10, should the tape
be coiled to form a roll, the convolutions of the roll would stick
together, giving rise to what is called "blocking," so that one
could not then unwind the roll. To prevent such blocking, the outer
surface of film face ply 12 is coated with a silicone or other
release agent 14 of the type commonly used in "Scotch" brand and
other pressure-sensitive plastic film tapes which come in roll
form.
[0036] The resultant roll 15, shown in FIG. 2 is loaded into a
pull-and-tear tape dispenser 16 suitable for a pressure-sensitive
tape, the dispenser, including a cutting blade 17 at its outlet.
Thus the tape drawn from roll 15 is extended through the outlet,
and a desired length thereof cut off by blade 17.
[0037] FIG. 3 shows a corrugated board carton 18 having
complementary flaps which are sealed by a paper-plastic film
laminate type T in accordance with the invention. When tape T is so
applied, its paper-base ply 10 is adhered by the pressure-sensitive
adhesive layer thereon to the flaps of the carton to close the
carton. The strength of the adhesive bond between the plastic film
ply and paper ply of the tape is greater than the
pressure-sensitive adhesive bond between the paper ply 10 and the
flap of the carton. In order to later open the carton, one strips
off tape T in toto. This action causes surface fibers on the
cardboard flaps to be ripped off and to adhere to the
pressure-sensitive adhesive layer. But no part of the tape remains
on the carton; hence the carton can be recycled in a paper
recycling facility.
[0038] The outer surface of the plastic film ply may be metallized
as by vacuum deposition to provide a decorative sealing tape. And
if the nature of the synthetic plastic material forming the plastic
ply is such that it has inherent release characteristics and
therefore does not require coating with a release agent, the outer
surface of this ply may be corona-discharge treated to render it
receptive to printing inks, so that this surface may be
decoratively or otherwise printed.
[0039] Also in practice, the pressure-sensitive adhesive coating
may be applied to the plastic film side of the laminate instead of
the paper side, as previously disclosed, in which case the release
agent for preventing blocking is applied to the paper side of the
laminate. And in this embodiment of the tape, since the
pressure-sensitive adhesive is coated on the exposed side of the
film ply, the surface of this ply must first be corona-discharge
treated to render it receptive to the adhesive.
[0040] In manufacturing a tape in accordance with the invention, a
laminate of the type disclosed in our U.S. Pat. Nos. 5,780,150 and
5,804,024 may be used to corona-discharge treat a plastic web
before it is adhered to a paper web to produce a paper film
laminate web. This laminate web is then slit into tapes of the
desired width.
[0041] While there has been disclosed preferred embodiments of the
invention, in practice, many changes may be made in the tape
without departing from the spirit of the invention. Thus one may
make a three-ply pressure sensitive tape whose core is an oriented
film cold-laminated on both sides to paper plies by a water-based
adhesive a pressure sensitive adhesive coating one paper ply, the
other paper ply being reserved for printing.
* * * * *