U.S. patent application number 10/974245 was filed with the patent office on 2005-05-26 for high bond strength, repositionable adherent sheet.
Invention is credited to Bouthilet, Andrew L., Hamilton, Peter Worthington, McGuire, Kenneth S., Poland, James Edward.
Application Number | 20050112314 10/974245 |
Document ID | / |
Family ID | 24122338 |
Filed Date | 2005-05-26 |
United States Patent
Application |
20050112314 |
Kind Code |
A1 |
Hamilton, Peter Worthington ;
et al. |
May 26, 2005 |
High bond strength, repositionable adherent sheet
Abstract
An adherent sheet material and method of making including at
least one adhesive, non-raised region protected from inadvertent
adherence to a contact surface. This adherent sheet material also
including a film having a front face and back face, wherein the
front face has a plurality of collapsible, non-adhesive protrusions
extending outwardly from the front face and adhesive, non-raised
region disposed between the protrusions. Also, a substrate is
bonded to the back face of film. An adherent sheet material
including a contact adhesive protected from inadvertent adherence
to a contact surface. This adherent sheet material also including a
film having a front face and back face, wherein the front face has
a plurality of collapsible, non-adhesive protrusions extending
outwardly from the front face and adhesive, non-raised region
disposed between the protrusions. The film also includes a number
density of protrusions from about 50 protrusions per square inch of
the film to about 150 protrusions per square inch of the film.
Also, the contact adhesive is disposed upon non-raised regions.
Inventors: |
Hamilton, Peter Worthington;
(Cincinnati, OH) ; McGuire, Kenneth S.; (Wyoming,
OH) ; Poland, James Edward; (Park Hills, KY) ;
Bouthilet, Andrew L.; (Cincinnati, OH) |
Correspondence
Address: |
THE PROCTER & GAMBLE COMPANY
INTELLECTUAL PROPERTY DIVISION
WINTON HILL TECHNICAL CENTER - BOX 161
6110 CENTER HILL AVENUE
CINCINNATI
OH
45224
US
|
Family ID: |
24122338 |
Appl. No.: |
10/974245 |
Filed: |
October 27, 2004 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10974245 |
Oct 27, 2004 |
|
|
|
09532576 |
Mar 22, 2000 |
|
|
|
6858285 |
|
|
|
|
Current U.S.
Class: |
428/40.1 ;
428/174 |
Current CPC
Class: |
B32B 3/28 20130101; C09J
2301/206 20200801; Y10T 428/2462 20150115; Y10T 428/2457 20150115;
Y10T 428/24628 20150115; Y10T 428/24479 20150115; Y10T 428/24612
20150115; B44C 1/105 20130101; Y10T 428/14 20150115; C09J 7/22
20180101; Y10T 428/2848 20150115; Y10T 428/28 20150115 |
Class at
Publication: |
428/040.1 ;
428/174 |
International
Class: |
B32B 009/00 |
Claims
What is claimed is:
1. An adherent sheet material comprising at least one adhesive,
non-raised region protected from inadvertent adherence to a contact
surface, said sheet material comprising: a film having a front face
and back face, said front face having a plurality of collapsible,
non-adhesive protrusions extending outwardly from said front face
and said adhesive, non-raised region disposed between said
protrusions, said protrusions having a number density from 10
protrusions per square inch of said film to 175 protrusions per
square inch of film; and a permeable substrate layer bonded to said
back face of said film with a laminating adhesive, said laminating
adhesive comprising air flow management means.
2. The sheet material of claim 1, further comprising a contact
adhesive disposed upon said non-raised regions.
3. The sheet material of claim 1, wherein a compressive force of at
least 0.1 psi is required to collapse said protrusions.
4. The sheet material of claim 1, wherein said density of
protrusions ranges from 50 protrusions per square inch of said film
to 150 protrusions per square inch of said film.
5. The sheet material of claim 1, wherein said substrate layer is a
member selected from the group consisting of flexible foil, fabric,
plastic film and paper.
6. The sheet material of claim 1, wherein said air flow management
means comprises air vent channels.
7. The sheet material of claim 6, wherein said sheet material is at
least temporarily selectively activatable.
8. The sheet material of claim 1, wherein said substrate further
comprises air flow management means.
9. The sheet material of claim 8, wherein said air flow management
means further comprises at least one aperture disposed within a
plurality of said protrusions.
10. An adherent sheet material comprising at least one adhesive,
non-raised region protected from inadvertent adherence to a contact
surface, said sheet material further comprising: a permeable film
having a front face and back face, said front face having a
plurality of collapsible, non-adhesive protrusions extending
outwardly from said front face and said adhesive, non-raised region
disposed between said protrusions, said film having a number
density of protrusions from about 10 protrusions per square inch of
said film to about 175 protrusions per square inch of said film; a
substrate layer bonded to said back face of said film with an
adhesive, said adhesive comprising air flow management means; and,
wherein said adhesive non-raised region having a peel force of at
least about 0.3 pounds per linear inch.
11. The sheet material of claim 10, wherein a compressive force
ranging from 0.5 pounds per square inch to 15 pounds per square
inch is required to collapse said protrusions.
12. The sheet material of claim 10, said number density of
protrusion ranges from 60 protrusions per square inch of said film
to 90 protrusions per square inch of said film.
13. The sheet material of claim 10, wherein said film further
comprises air venting channels.
14. The sheet material of claim 13, wherein said air vent channel
comprises at least one aperture disposed within a plurality of said
protrusions.
15. The sheet material of claim 10, wherein said protrusions have a
non-adhesive coating disposed thereon.
16. An adherent sheet material comprising a contact adhesive
protected from inadvertent adherence to a contact surface, said
sheet material comprising: a film having a front face and back
face, said front face having a plurality of collapsible protrusions
extending outwardly from said front face and non-raised regions
disposed between said protrusions; a porous substrate layer bonded
to said back face with a laminating adhesive, said laminating
adhesive comprising air flow management means; and, said adhesive
disposed upon said non-raised regions, said film having a number
density of protrusions from about 50 protrusions per square inch of
said film to about 150 protrusions per square inch of said
film.
17. The sheet material of claim 16, wherein said protrusions have a
height ranging from 0.01 inches to 0.04 inches.
18. The sheet material of claim 17, wherein each of said
protrusions has a protrusion base surface area ranging from 0.0007
inches to 0.008 square inches.
19. The sheet material of claim 16, wherein said protrusions are
dome-shaped and have a base diameter ranging from 0.03 inches to
0.1 inches.
20. The sheet material of claim 16, wherein said film is high
density polyethylene having a thickness ranging from 0.0003 inches
to 0.003 inches.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 09/532,576 filed Mar. 22, 2000.
FIELD OF THE INVENTION
[0002] The present invention relates to flexible sheet materials
having an adhesive for providing a high bond strength and having
outermost surface features for preventing premature adhesion to an
contact surface such as a target surface. Even more particularly,
the present invention relates to repositionable wall covering,
tapes, labels, etc. comprising a flexible film having protrusions
that act to space an adhesive from a target surface until the wall
covering is pressed thereagainst.
BACKGROUND OF THE INVENTION
[0003] Decorative sheet-like materials, such as wall coverings are
well known in the art. Such sheet materials are generally formed of
paper, plastic, metal foil, fabric material or some combination
thereof having a pattern or design printed or embossed on the front
surface, with the back surface being coated by the user with an
adhesive, such as glue, cement, or the like (generally known as
"wallpaper paste") by which the wall covering may be bonded to a
wall, ceiling or other target surface.
[0004] Other types of wall coverings include those having a plastic
decorative surface and a backing of woven or non-woven fabric or
paper. The back surface is adapted to be coated by the user with
the adhesive set forth above in order to secure the wall covering
to a surface. However, users dislike the inconvenience of mixing
and applying the paste. Additionally, there are prepasted wall
coverings available. However, these prepasted wall coverings need a
water trough and this can be both time consuming and messy. Also,
both the non-prepasted and prepasted wall coverings require the
user to perform additional steps to apply the wall covering to the
target surface. Generally, once these conventional wall coverings
are applied to the target surface, only slight adjustments in their
position upon the target surface may be made before the adhesive
cures.
[0005] To eliminate the additional steps and mess of using
"wallpaper paste", wall coverings have attempted to use pressure
sensitive adhesives. Pressure sensitive adhesives are known to
provide immediate adhesion between two materials upon contact. Such
adhesives rely on quick set-up reaction or rapid cure time for
prompt adhesion. In the art of tapes, labels, wall coverings and
other articles using pressure sensitive adhesives to adhere an
adhesive coated surface to a target surface, there has been
recognized the problem of premature adhesion or sticking to contact
surfaces, such as a target surface. That is, before the adhesive
coated surface can be properly positioned over a target surface,
inadvertent contact of the adhesive with the target surface causes
premature adhesion at one or more locations, thereby inhibiting
proper positioning. For example, due to this premature sticking to
the target surface, wall coverings are very difficult to apply to a
wall and then reposition, as occurs when lining up the patterns of
at least two wall covering sheets.
[0006] To reduce this premature adhesion to contact surfaces,
pressure sensitive adhesive wall coverings have typically used
adhesives with a low bond strength or tack to attach it to the
target surface. However, this creates an additional problem in that
the wall coverings lack sufficient tack to maintain attachment to
the target surface for long periods of time. Because of this low
tack, over a period of time the user experiences the wall covering
peeling from the wall especially at the sheet margins.
[0007] However, pressure sensitive adhesives ("PSA") with a higher
bond strength or tack, i.e., aggressive or permanent pressure
sensitive adhesives, generally have not been used to combat the
problem of insufficient tack. This is due to the fact that these
permanent PSA's are very tacky and tenacious and thus become very
difficult to handle and use. For example, the wall covering will
prematurely adhere to contact surfaces, such as the user's hands or
the target surface. Once the adhesive has made premature contact
with the surface, the user generally cannot remove the wall
covering or even make slight adjustments in its position without
destroying the wall covering or significantly reducing the bond
strength. Therefore, most PSA wall coverings use low tack PSA's in
an attempt to make the wall coverings easy to use. However, as
mentioned above, even these low tack PSA's can cause the problem of
premature adhesion to a contact surface. Although the user can
generally separate the low bond strength wall covering from the
contact surface without destroying the wall covering, it still
frustrates the user and wastes the user's time.
[0008] Others have tried to solve the problem of premature adhesion
to contact surfaces by applying a removable release paper to the
adherent sheet material such as found for example in U.S. Pat. No.
5,487,929 issued to Rusincovitch, Jr. et al. on Jan. 30, 1996.
However, this release paper adds additional costs to the sheet
material and requires both the manufacturer and user to perform
additional steps. Others have also tried to solve the specific
problem of premature adhesion of a adherent, decorative sheet
material by placing solid protrusions as spacers between the
decorative sheet and the target surface such as also found in U.S.
Pat. No. 5,487,929, issued Jan. 30, 1996, to Rusincovitch, Jr. et
al. However, these protrusions are solid and thus require more
material and do not completely collapse.
[0009] Still others have tried to solve the problem of premature
adhesion of an adherent sheet material to contact surfaces by
placing spacers to separate the pressure sensitive adhesive from
the target surface, such as found, for example, in U.S. Pat. No.
4,376,440 to Whitehead et al., U.S. Pat. No. 5,141,790 to Calhoun
et al., U.S. Pat. No. 4,959,265 to Wood et al., U.S. Pat. No.
5,344,693 to Sanders, U.S. Pat. No. 4,061,820 to Magid et al., and
European Patent Application No. 0 623 332 A1 to Lauritzen.
Generally, this art has focused on the use of stand-offs with
pressure sensitive adhesives primarily in the area of sanitary
napkins. However, different solutions are needed for flexible,
adherent sheet materials having protrusions intended to be adhered
to smooth or rigid surfaces. Commonly assigned, U.S. Pat. No.
5,662,758 issued to Hamiltion et al. on Sep. 2, 1997, and U.S. Pat.
No. 5,871,607 issued to Hamilton et al. on Feb. 16, 1999, provide a
thorough description of the art in adherent sheets protected from
premature adhesion and are herein incorporated by reference.
[0010] Both of these commonly assigned patents involve adherent
sheets which are protected from premature adhesion to a contact
surface via hollow protrusions. However, generally, neither deal
with wall coverings, labels or other adherent sheet materials
having protrusions with either an additional substrate or a high
bond strength.
[0011] It is well known in the art to bond a substrate to a flat
film such as by laminating the two together using pressure and a
laminating adhesive. However, if the film is formed with hollow
protrusions then a problem exists in how to combine the substrate
with the film that has hollow protrusions without crushing the film
protrusions. Additionally, once the substrate is bonded to the
film, an additional problem of air entrapment within the
protrusions is created. For example, the substrate and potentially
the laminating adhesive may now have created a gas barrier that
prevents air from escaping from the protrusions when the
protrusions are made to collapse. If the air does not escape from
the protrusion, the protrusion may not fully collapse and thus
prevent full adhesion of the sheet material to the target
surface.
[0012] U.S. Pat. No. 5,906,883, issued May 25, 1999, to
Blanc-Brude, discusses plurality of interconnected non-adherent
elements made from a substrate. However, it is believed that this
requires a difficult process to make.
[0013] Therefore, such adherent sheet materials leave room for
improvement in ease of use and manufacture, cost, repositionability
and bond strength.
[0014] Accordingly, it would be desirable to provide an improved
multi-layered, adherent sheet material which is inexpensive to
make, has means for protecting the adhesive from prematurely
adhering to contact surfaces yet is efficient to store and
ship.
[0015] It would also be desirable to provide such a material which
is easily handled and manipulated by a user during the application
process and is repositionable, yet forms an adequate bond with a
variety of materials and surfaces to effectively adhere to the
target surface.
[0016] It would also be desirable to provide a wall covering which
is easily handled and manipulated by a user during the application
process and is repositionable, yet forms an adequate bond against a
variety of materials and surfaces to effectively adhere to the
target surface.
SUMMARY OF THE INVENTION
[0017] An adherent sheet material including at least one adhesive,
non-raised region protected from inadvertent adherence to a contact
surface. This adherent sheet material also including a film having
a front face and back face, wherein the front face has a plurality
of collapsible, non-adhesive protrusions extending outwardly from
the front face and adhesive, non-raised region disposed between the
protrusions. Also, a substrate is bonded to the back face of
film.
[0018] An adherent sheet material including at least one adhesive,
non-raised region protected from inadvertent adherence to a contact
surface. This adherent sheet material also including a film having
a front face and back face, wherein the front face has a plurality
of collapsible, non-adhesive protrusions extending outwardly from
the front face and adhesive, non-raised region disposed between the
protrusions. The film also includes a number density of protrusions
from about 10 protrusions per square inch of the film to about 175
protrusions per square inch of the film. The adherent sheet
material has a peel force of at least about 0.3 pounds per linear
inch.
[0019] An adherent sheet material including a contact adhesive
protected from inadvertent adherence to a contact surface. This
adherent sheet material also including a film having a front face
and back face, wherein the front face has a plurality of
collapsible, non-adhesive protrusions extending outwardly from the
front face and adhesive, non-raised region disposed between the
protrusions. The film also includes a number density of protrusions
from about 50 protrusions per square inch of the film to about 150
protrusions per square inch of the film. Also, the contact adhesive
is disposed upon said non-raised regions.
[0020] Also included in the present invention is a method for
making an adherent sheet material having a film with protrusions, a
contact adhesive protected from inadvertent adherence and a
substrate bonded to the film. The sheet being adherable to a target
surface only when pressed thereagainst. The method includes coating
a forming drum with a contact adhesive. The forming drum has a top
surface, wherein this surface has a plurality of recesses therein.
This coating step applies the contact adhesive to the top surface
without bridging the recesses. The next step in the method is
placing a piece of flexible film in contact with the contact
adhesive on the top surface of the forming drum. The contact
adhesive will preferentially adhere to the piece of flexible film.
Then, a piece of flexible film is formed to create a plurality of
protrusions extending into the recesses of the forming drum. The
plurality of protrusions being registered with the contact
adhesive. Also, a substrate is coated with a laminating adhesive
and placed in contact with a back face of the film. After this
step, the substrate and the film are joined with pressure to form a
bonded layer. Finally, the piece of sheet material is removed
together with the pressure sensitive adhesive from the forming
drum.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] While the specification concludes with claims particularly
pointing out and distinctly claiming the present invention, it is
believed that the present invention will be better understood from
the following description in conjunction with the accompanying
Drawing Figures, in which like reference numerals identify like
elements, and wherein:
[0022] FIG. 1 is a cross-sectional view of a adherent sheet
material embodiment of the present invention;
[0023] FIG. 2 is a top planar view of the adherent sheet material
shown in FIG. 1;
[0024] FIG. 3 is a cross-sectional view of a adherent sheet
material shown in FIG. 1 in contact with a contact surface;
[0025] FIG. 4 is a cross-sectional view of a preferred adherent
sheet material embodiment in contact with a contact surface;
[0026] FIG. 5 is a cross-sectional view of a adherent sheet
material shown in FIG. 4 in contact with a contact surface, wherein
a force (F) has been applied to adherent sheet material causing
protrusions to collapse;
[0027] FIG. 6 is an alternative embodiment of a adherent sheet
material of the present invention, wherein the lamating adhesive
follows the contours of the protrusion along the back face of the
film;
[0028] FIG. 7 is an alternative embodiment of a adherent sheet
material of the present invention, wherein the laminating adhesive
is discontinuous;
[0029] FIG. 8 is an alternative embodiment of a adherent sheet
material of the present invention, wherein the film is
apertured;
[0030] FIG. 9 is process flow chart of a method for making the
composite sheet material of the present invention, disclosing a
automated embossing process to form sheet material of the present
invention;
[0031] FIG. 10 is a is a side elevation view of the nip region of
the method for making the composite sheet material of the present
invention; and
[0032] FIG. 11 is a side elevation view of the pressure drum and
the female embossing drum, wherein the substrate is bonded to the
formed film having protrusions of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0033] Referring now to the drawings, and more particularly to
FIGS. 1-8, there is shown a preferred embodiment of the present
invention, which provides the adherent sheet material and is
generally indicated as 10. As shown in FIG. 1 (cross-sectional
view), adherent sheet material 10 includes a piece of a flexible
film sheet 20 having an operational front face 22, a back face 24,
non-adhesive, three-dimensional protrusions 26 extending outwardly
from the front face 22 and adhesive, non-raised regions 28 located
between the protrusions 26.
[0034] Sheet material 10 is a selectively-activatible,
adhesive-bearing structure which bonds sheet material 10 to a
target surface. The target surface for the adhesive system includes
but is not limited to walls, table tops, shelves, etc.
[0035] As utilized herein, the term "selectively-activatible" is
used to refer to materials which exhibit substantially non-adherent
properties when brought into contact with target surfaces until
some action is taken by a user to "activate" the material to reveal
adhesive properties. Accordingly, selectively-activatible
properties differ from permanently-active strips of adhesive which
rely upon removal of liner materials (typically silicone-coated
paper strips or films) to expose the adhesive for use.
[0036] Selective activation of such materials-allows the user to
properly position sheet material 10 upon a target surface before
activation and adhesion are accomplished, as well as minimizing the
likelihood of contamination of the adhesive system before use. This
characteristic permits the sheet material 10 to be manipulated in
any desired mode without encountering the difficulties of premature
adhering of the adherent sheet to itself or to other contact
surface 50s, and without the need for separate release sheets,
liners, microspheres or the like which often need to be removed
prior to contact with the target surface. If desired, the selective
activation process may be temporary, i.e., minimal contact between
adherent, non-raised regions 28 and a contact surface 50 for
evaluation of sheet material's 10 position upon target surface and
then may be de-activated without destroying sheet material 10 for
either removal of sheet material 10 from or repositioning it upon
target surface 50 for further use without significant loss of
adhesive capability.
[0037] Regardless of the manner of activation, materials useful as
an adhesive system in accordance with the present invention will
exhibit an adhesive, adherent or tacking character as opposed to
merely a clinging or affinity character. As utilized herein, the
terms "adhesive" is utilized to refer to the ability of a material
to exhibit an adherent character whether or not it actually
includes a composition commonly understood and labeled as an
adhesive. Accordingly, such materials will form a bond or seal when
in contact with itself or another target surface as opposed to
merely being attracted to such surface. While a number of
approaches such as the use of selectively adherent materials may be
utilized to provide the desired adhesive properties, a presently
preferred approach is to utilize a pressure sensitive adhesive.
[0038] When designing materials useful as an adhesive system in
accordance with the present invention, it may be desirable to
tailor the particular choice of adhesive material or agent so as to
provide either a permanent bond or a releasable bond as desired for
a particular application. In accordance with the preferred
embodiment of the present invention, depending upon extent of the
activation employed, the sheet 10 can demonstrate a releasable
bond, i.e., a temporary bond, be either removed without destroying
sheet material 10 or repositioned and then activated completely
once placed in desired position upon target surface to form a
permanent bond between sheet 10 and target surface.
[0039] Referring to FIGS. 1-3, sheet material 10 includes adhesive,
non-raised regions 28 on film sheet 20 between and around
protrusions 26. Adhesive, non-raised regions 28 have adhesive
properties which can be achieved in a variety of different ways.
One such way to provide non-raised regions 28 adhesive
characteristics is to fabricate film sheet 20 from a material that
demonstrates adhesive characteristics, including but not limited to
plasticized polymers, i.e., polyvinyl chloride, silicones,
hydrogels, polyvinylidene dichloride, Kraton Rubber, urethane
polymers, plastisols, plasticized waxes, i.e., organic waxes
(beeswax), inorganic waxes (paraffin), etc., gelatins and other
organic based, proteinaceous materials.
[0040] Also, U.S. Pat. No. 6,194,062. describes materials that
exhibit adhesive or "cling" properties and is herein incorporated
by reference. As discussed above, such materials can exhibit
adhesive or "cling" properties on a constant basis, such that they
cling to themselves and to other surfaces whenever brought into
proximity with them, whether desirable or not. Such materials often
incorporate resins, additives, tackifiers, or other materials to
achieve the target level of cling. Suitable methods of measuring
and quantifying this cling property are described in ASTM test
methods D5458-95 and D3354-89. Test method D5458-95 is useful for
measuring cling between two layers of film in both stretched and
unstretched conditions, and utilizes a 1 inch wide film strip
adhered to a flat film attached to an inclined surface. The force
required to remove the film strip from the flat film is measured.
Test method D3354-89 is useful for measuring the degree of blocking
(unwanted adhesion) existing between overlapping layers of plastic
film. Film-to-film adhesion is expressed as a blocking load in
grams which will cause two layers of film to separate with an area
of contact of 100 square centimeters.
[0041] Another such way to provide the non-raised regions 28
adhesive characteristics is to fabricate film sheet 20 from
materials with activated adhesive systems, including but not
limited water activated adhesives, ultraviolet light activated
systems, encapsulated adhesive, anaerobic, i.e.,
cyanoacrylates.
[0042] Again, referring to FIGS. 1-3, a third way to provide
non-raised regions 28 of film sheet 20 with adhesive
characteristics is to dispose upon or coat on a surface of
non-raised regions 28, preferably a contact adhesive 12, including
but not limited to a pressure sensitive adhesive ("PSA").
[0043] Generally, the pressure sensitive adhesive (PSA) useful in
the invention can be any adhesive known to those skilled in the
art, including but not limited to elastomeric-type PSAs comprising
natural rubber, reclaimed rubber, styrene-isoprene-styrene rubber,
butadiene-acrylonitrile rubber, polyvinyl ether rubber,
styrene-butadiene-styrene rubber, butyl rubber, polyisobutylene
rubber, nitrile rubber, styrene-butadiene rubber, polyurethane,
polysulfide, polyesters, silicone resins and gums, neoprene rubber,
acrylic, methacrylic, polyacrylate ester rubber, and vinyl and
mixtures thereof.
[0044] Contact adhesive 12 is preferably a pressure sensitive
adhesive, also preferably a hot melt adhesive, most preferably an
adhesive of specification number X 801 334 03, made by Ato Findley
Co. of Wauwatosa, Wis. Contact adhesive 12 may be refastenable,
releaseable, permanent, or otherwise. The size, shape and spacing
of protrusions 26 is preferably selected to provide a continuous
contact adhesive 12 path surrounding protrusions 26 but is not
necessary to practice the invention and thus a discontinuous
adhesive path could be applied upon non-raised regions 28. Contact
adhesive layer 12 has a thickness of X which is preferably from
about 0.001 inches to 0.010 inches, most preferably 0.002 inches of
pressure sensitive adhesive.
[0045] If film sheet 20 is fabricated from a material having
adhesive properties in order to provide non-raised regions 28 an
adhesive property, then protrusions 26 being made of the same
material would need some type of non-adhesive coating ("cappers")
to permit sheet material 10 to slide or be repositioned over
contact surface 50. The cappers can be applied minimally over
protrusion apex 27 of protrusions 26, preferably the entire surface
of each of protrusions 26. These cappers demonstrate non-adhesive
properties and include but are not limited to silicones, inorganic
powders, i.e., talc, powdered mica, calcium carbonate, etc., inks
and other non-tacky coatings well known in the art. These
non-adhesive cappers, prevent the activation of film sheet's 20
adhesive properties, thus permitting repositionability and
preventing premature adhesion to a contact surface 50 of sheet
10.
[0046] If film sheet 20 is fabricated from a material having
adhesive properties that require an intentional activation to
activate the adhesive properties of the material, then protrusions
26 do not require any type of non-adhesive, coating or cap. The
user will selectively activate only the adhesive properties of
adhesive, non-raised regions 28 and not the adhesive properties of
non-adhesive, protrusions 26.
[0047] Still referring to FIGS. 1-3, film sheet 20 is preferably
fabricated from a polymer that does not have adhesive
characteristics, which may be made from homogeneous resins or
blends thereof. Single or multiple layers within the film structure
are contemplated, whether co-extruded, extrusion-coated, laminated
or combined by other known means. Useful resins include, but are
not limited to, polyethylene (PE), polypropylene (PP), polyethylene
terephthalate (PET), polyvinyl chloride (PVC), polyvinylidene
chloride (PVDC), latex structures, nylon, etc. Polyolefins are
generally preferred due to their lower cost and ease of forming but
are not necessary to practice the invention. High density
polyethylene (HDPE) is most preferred to fabricate the film sheet.
Other suitable materials to fabricate the film from include, but
are not limited to, aluminum foil, coated (waxed, etc.) and
uncoated paper, coated and uncoated wovens, scrims, meshes,
nonwovens, and perforated or porous films, and combinations
thereof. In a particularly preferred embodiment, the flexible film
sheet material is a formed film from about 0.0001 inch to about
0.005 inches, more preferably about 0.001 inch thick film.
[0048] Protrusions 26 are discreet, collapsible three-dimensional
outermost surface features formed from film sheet 20. Protrusions
26 extend outwardly from the front face 22 in a substantially
perpendicularly direction, occupying a voided space 25 under
protrusions 26 (FIG. 1). Protrusions 26 have heights (H) which are
preferably less than their diameters D1, so that when they
collapse, they collapse along an axis which is substantially
perpendicular to a plane of sheet 10. This mode of collapse avoids
protrusions 26 folding over and blocking adhesive 12 from contact
with a target surface 50. Commonly assigned, U.S. Pat. No.
5,662,758 issued to Hamiltion et al. on Sep. 2, 1997, and U.S. Pat.
No. 5,871,607 issued to Hamilton et al. on Feb. 16, 1999, and
commonly assigned, U.S. patent application Ser. No. 08/745,340,
filed Nov. 8, 1996 in the name of Hamilton et al. and Ser. No.
09/369,743, filed Aug. 6, 1999 in the name of Hamilton et al.
provide detailed information on adherent sheets having formed film
sheets with protrusions and are herein incorporated by
reference.
[0049] Protrusions 26 are collapsible in that they are hollow
protrusions that, once placed under a significant applied pressure,
deform from a substantially three-dimensional structure (as shown
in FIG. 1) to a substantially two-dimensionsal structure (as shown
in FIG. 5). The term "discreet" is used herein to refer to the fact
that film sheet 20 separates voided spaces 25 of each protrusion
26, i.e., protrusions 26 are not interconnected to any other
individual protrusion 26. In other words, the air entrapped within
the voided space 25 of one of protrusion 26 cannot travel to any of
the other protrusions 26.
[0050] Protrusions 26 are preferably domed-shaped but can be a
variety of shapes without changing the scope of the invention, such
as conical, cylindrical, hemispherical, toroidal and pyramidal.
Preferably, protrusions 26 have a protrusion apex 27 which is a
point on protrusions 26 having the greatest perpendicular distance
from the front face 22 of the film sheet 20.
[0051] The number density of protrusions 26, i.e., the number of
protrusions per square inch, is an important parameter in the
context of the present invention because it is one determination of
the compressive strength of protrusions 26. The term "compressive
strength" is used herein to refer to a perpendicularly applied
force (F) a particular three-dimensional sheet can support for a
given amount of sheet deflection. For this particular case,
protrusion 26 deflection is analogous to sheet deflection. This
information is important because it quantifies the perpendicularly
applied force (F) required to deform a particular sheet to a given
protrusion height H. Protrusion height (H) is defined as the
perpendicular distance from the front face 22 of the film 20 to the
protrusion apex 27. For example, from FIG. 1, if a thickness (X) of
adhesive 12 is coated across the front face 22 of the film sheet 20
such that it fills the adhesive, non-raised regions 28 between
protrusions 26, the force (F) could be determined that would deform
the sheet 10 to the height (X) of the adhesive 12, thus exposing
the adhesive 12 to the contact surface 50.
[0052] Compressive Strength Analytical Test Method
[0053] This test was used to determine the compressive strength of
the film sheet 20 at different levels of protrusion 26
deformation.
[0054] A circular sample with a diameter of 0.8 inches was cut from
the film sheet material. The circular sample was then placed on the
lower, stationary platform of an INSTRON brand model 8511
compression tester (available from INSTRON Corporation, Caston,
Mass.). The upper moveable platform of the compression tester was
then lowered until it barely came in contact with the sheet's
protrusions. The three-dimensional sample was then fully compressed
into a substantially two-dimensional sheet at an upper platform
rate of 0.05 pounds per second. The compression tester was operated
by the INSTRON Plus 8500 display unit in load control running from
0 to 10 pounds. Displacement of the upper platform and compressive
load were measured and recorded throughout the test on an
oscilloscope.
[0055] Based upon this test method, the present invention had a
compressive strength of at least about 0.1 pound per square inch,
preferably of at least about 1 pound per square inch, more
preferably from about 0.5 pounds per square inch to about 15 pounds
per square inch, even more preferably from about 3 pounds per
square inch to about 10 pounds per square inch before contacting
adhesive, non-raised regions 28, preferably contact adhsive 12.
[0056] Referring to FIGS. 1 and 2, the protrusions 26 have a
protrusion height (H) preferably from about 0.01 inches to about
0.1 inches, more preferably 0.015 inches to about 0.040 inches,
even more preferably 0.20, most preferably 0.025 inches and a base
surface area from about 0.001 square inches to about 0.0065 square
inches, most preferably 0.004 square inches. In the preferred
embodiment, the base surface area (SA) is calculated by the formula
of SA=1/4.pi. (D1).sup.2. In a even more preferred embodiment,
protrusions 26 have a base diameter (D1) from about 0.030 inches to
about 0.10 inches, more preferably from about 0.040 inches to about
0.09 inches, most preferably 0.070 inches. Center-to-center spacing
(C) of protrusions 26 can be randomly spaced using the method
described in commonly assigned, U.S. Pat. No. 5,965,235, issued to
McGuire et al. on Oct. 12, 1999, and herein incorporated by
reference. FIG. 2 shows a preferred embodiment in which
center-to-center spacing (C) is uniformly spaced, more preferably
from about 0.05 inches to about 0.15 inches, even more preferably
from about 0.07 inches to about 0.115, most preferably 0.105
inches.
[0057] FIGS. 3 and 4 show a contact surface 50, which may be smooth
and rigid and is typically non-deformable, being spaced away from
layer of contact adhesive 12 by protrusions 26. Contact surface 50
is defined as a surface generally parallel to front face 22 of film
sheet 20 which contacts the protrusions 26 preferably at their
protrusion apex 27. Contact surface 50 can be a variety of surfaces
which sheet material's 10 adhesive layer 12 could come in contact
with, such as a user's hand, drum, rollers, the sheet material
itself and target surfaces such as walls, table tops, shelves,
windows, etc.
[0058] Film protrusions 26 prevent the contact adhesive 12 from
contacting any contact surfaces until the film 20 is intentionally
pressed against desired contact surface 50, i.e. target surface 50.
The adherent sheet material 10 is applied to contact surface 50
wherein the film protrusions 26 make contact with contact surface
50 and thus protect the contact adhesive 12 from contacting contact
surface 50. The protrusions 26 prevent the premature adhesion of
the adherent sheet 10, such as a wall covering, from prematurely
adhering to the contact surface 50. This also permits the user to
position sheet material 10 upon target surface 50 and then
reposition, i.e., slide, sheet 10 to another position numerous
times without destroying sheet material 10 or substantially
reducing contact adhesive's 12 tack.
[0059] In particular, FIG. 4 shows a preferred embodiment of
adherent sheet material 10 further consisting of a substrate 40
bonded to back face 24 of film sheet 20. This substrate 40 may be
bonded to the back face 24 of the film sheet 20 by any type and
method that suits the needs of the application. For example, they
may be bonded together by way of heat-sealing, ultrasonic welding,
preferably a laminating adhesive 30, including but not limited to
slot coating and spray coating, etc., most preferably spray
coating.
[0060] Especially useful but not necessary for this lamination is a
tacky PSA, including but not limited to all the PSA's mentioned in
the detailed description of contact adhesive 12 set forth above.
The protrusion's 26 tendency to rebound to its' undeformed height
can cause the sheet 20 to lose some or all of its' adherence to the
target surface 50, but when a pressure sensitive adhesive 30 is
used between the adherent sheet 20 and the substrate 40, the PSA 30
serves to help maintain the protrusions 26 in a collapsed state due
to the adherence of the adhesive layer 30 to the collapsed
protrusion 26 as shown in FIG. 5. Similarily, when a presurre
sensitive adhesive 30 is applied to the back face contours of
protrusions 26 in an alternative embodiment shown of FIG. 6, the
same advantageous effect will be realized. The substrate 40 may be
made of a variety of materials currently used as wall coverings,
including but not limited to flexible and partially non-flexible
foils, fabric, plastic films, and papers.
[0061] FIG. 5 also shows protrusions 26 collapsed under a force as
indicated by force (F), applied to back face 24 of film sheet 20.
Once protrusions 26 collapse, non-adhesive region 28, preferably
contact adhesive 12, is caused to adhere to contact surface 50.
This adhesion can be permanent or temporary depending upon how many
protrusions 26 were collapsed. For example, if only a minimal
number of protrusions are collapsed, sheet 10 will temporarily bond
to target surface 50 because only a small percentage of contact
adhesive 12 is adhered to contact surface 50. This temporary
adhesive state allows the user to evaluate the position of sheet
material 10 upon target surface 50 for only a very short time
period; and if it is not in a desired position, remove sheet
material from target surface and reposition it upon the target
surface 50. When the user has found the final position of the
wallpaper, a compressive force is applied to entire substrate 40
substantially perpendicular to a plane of sheet 10, thus deforming
film protrusions 26. This exposes the adhesive 12 to the target
surface 50 and thus preferably provides a permanent adherence for
sheet material 10. The substrate 40 is then the outermost layer and
may contain a decorative pattern such as is found in wall
coverings. This sheet material 10 may be combined as a kit with
instructions for use, consisting of the following instructions:
[0062] (a) positioning sheet material 10 on target surface 50 with
front face 22 in contact with surface 50, until sheet material 10
is in desired location upon target surface 50; and
[0063] (b) applying a force (F) perpendicular to and across the
substrate sufficient to collapse the collapsible protrusions 26,
whereby the contact adhesive 12 comes in contact with the surface
50.
[0064] In an alternative embodiment, a low tack contact adhesive,
including but not limited to low tack PSA's, can be applied to the
protrusion "tips" or protrusion apex 27. This low tack PSA would
provide enough tack to hold sheet 10 to target surface 50
temporarily, but protrusions 26 would still prevent target surface
50 from contacting adhesive, non-raised regions 28, preferably
contact adhesive 12, which consists of a high tack adhesive. Again,
once sheet material 10 is position (and repositioned) upon target
surface 50, a perpendicular force (F) applied to entire back face
24 of film sheet 20 will collapse protrusions 26 and permanently
bond sheet material 10 to target surface 50.
[0065] In the preferred embodiment, once the adherent sheet 20 has
been selectively activated, it has a peel force of at least about
0.3 pounds per linear inch, preferably at least about 0.5 pounds
per linear inch, most preferably a peel force from about 0.5 pounds
per linear inch to about 0.9 pounds per linear inch. The term "peel
force" is used herein to refer to the force (F) required to peel
the adherent system, i.e., sheet 10, from a contact surface 50,
i.e., target surface 50, in a substantially perpendicular direction
from target surface 50. The peel strength, i.e., peel force, of the
adhesive is preferably measured by Pressure Sensitive Tape Council
Method PSTC-1. A 12 inch (30.5 cm) long by 1 inch (2.5 cm) wide
strip of film is rolled once against a smooth stainless steel
surface at a rate of 12 inches (30.5 cm) per minute using a 4.9
pound (2.25 kg) roller and then tested as having an average
adhesion value of greater than about 0.3 pounds per linear inch
(pli).
[0066] When bonding substrate 40 to film-sheet 20, substrate 40
will act as a gas barrier, entrapping the air in voided space 25 of
protrusions 26, if certain precautions are not taken. This
entrapped air can be problem because the air, if not allowed to
escape, can prevent protrusions 26 from completely collapsing.
There are a variety of ways to approach solving this potential
problem of air flow management. The term "air flow management" as
used herein refers to the many different ways of providing a path
or channel so that the air entrapped within voided space 25 can
escaped as protrusions 26 are being collapsed. These air vent paths
or channels can be at a macroscopic or microscopic level and either
intentionally formed or naturally occurring within film sheet 20,
substrate 40 or laminating adhesive 30, either singly or in
combination. To incorporate the air vent channels in sheet material
10, film sheet 20, substrate 40 or laminating adhesive 30, either
singly or in combination can be porous, permeable, perforated,
discontinuous or aperatured.
[0067] The term "porous" is used herein to refer to the ability of
a material to admit fluids, preferably gas, to pass through its
pores or interstices. The term "permeable" is used herein to refer
to the ability of material to admit fluids, preferably gas, to pass
through its pores or interstices whether intentionally induced or
naturally occurring within the material. The term "perforated" is
used herein to refer to a plurality of holes punched in a material.
The term "discontinuous" is used herein to refer to the intentional
use or application of a material that is not a continuous layer of
material such that the material does not form a barrier layer to
the gas escaping voided space 25 of protrusions 26 when protrusions
26 are collapsed. The term "apertured" is used herein to refer to
any hole, slit or opening of any size or shape intentionally formed
within such materials.
[0068] In a preferred embodiment depicted in FIG. 4, the laminating
adhesive 30 and substrate 40 should be either porous, permeable,
perforated, discontinuous, aperatured or some combination thereof,
thereby permitting the protrusions 26 to collapse more completely
by displacing any air trapped in the voided volume 25 of the
protrusions 26 through the air vent channels within the laminating
adhesive 30 and/or substrate 40. For example, one embodiment of the
present invention includes both a substrtate 40 and laminating
adhesive 30 that are either porous or permeable. In another
embodiment, both substrtate 40 and laminating adhesive 30 are
perforated under protrusions 26 such that entrapped air in void
space 25 can escape through the perforated air vent channels.
[0069] In an alternative embodiment depicted in FIG. 6, substrtate
40 is either porous, permeable, perforated, discontinuous,
aperatured or some combination thereof and laminating adhesive 30
follows the contours of protrusions 26 along back face 24 of film
sheet 20 forming non-adhesive regions under protrusions 26. This
embodiment does not require adhesive 30 to be discontinuous or
permeable to permit protrusions 26 to more completely collapse. In
yet another embodiment of sheet material 10, laminating adhesive 30
may be discontinuous by microscopic channels imparted in it by the
spray coating process. The laminating adhesive 30 may also be
discontinuous by way of macroscopic channels formed by the periodic
application of laminating adhesive 30 upon substrate 40 forming a
non-continuous path as shown in FIG. 7.
[0070] In yet another embodiment of sheet material 10, film sheet
20 is porous, permeable, perforated, discontinuous or any
combination thereof and substrate 40 can be gas impermeable or
include any of the above mentioned properties to provide additional
air vent channels. Other alternative embodiments which allow for
trapped air to be displaced from the voided volume 25 of the
protrusions 26 through film sheet 20 include, but are not limited
to, intentionally permeable sheet material, such as found in paper
sheets, breathable sheets (additive), etc.
[0071] FIG. 8 shows another alternative embodiment wherein
protrusions 26 are apertured on front face 22, as well as the back
face 24, of the film sheet 20 forming an opening at protrusion apex
27. Having the protrusions 26 open on both the front face 24 and
back face 24 allows for the air trapped in the voided volume 25 of
the protrusions 26 to be displaced along a contact surface when
compressed.
[0072] A method of making is illustrated in FIG. 9. The film sheet
20 may be formed by vacuum thermoforming or embossing or other
means as shown and described in U.S. Pat. Nos. 5,662,758;
5,871,607; and 6,193,918, which are herein incorporated by
reference. Embossing is the preferred method of making the adherent
sheet material 10 and is set forth below.
[0073] FIGS. 9-11 show an automated process for making sheet
material 10, generally indicated as 60. A drum 64 (hereinafter
referred to as "female embossing drum" 64) has an outermost
diameter that has patterned depressions. This outermost diameter is
treated to have a low surface energy, i.e., a release coating is
applied, so that the adhesive 12 will not readily wet it, or in
other words, the adhesive 12 will have a greater affinity to the
film sheet 20 than the female embossing drum 64. This outermost
diameter is then coated with the adhesive 12 by an adhesive
deposition system 62 such that the adhesive 12 is only transferred
to the outermost diameter of the female drum 64 and is not
transferred into the patterned depressions. This adhesive
deposition drum 62 is positioned upstream from the female embossing
drum 64 and a matching drum 68 with matching patterned male drum
pins (hereinafter referred to as "male embossing drum" 68). The
male embossing drum 68 is mated with the female embossing drum 64
such that each of the male drum pins on the male embossing drum 68
has a corresponding depression in the female embossing drum 64 into
which it engages at a nip region 70.
[0074] Automated process 60 introduces a film sheet 20 into this
nip region 70 whereby it is permanently, mechanically deformed by
the matching set of embossing drums (64 and 68), and their
corresponding male drum pins and female drum depressions as shown
in FIG. 10. The deformation is such that film sheet 20 retains the
three-dimensional shape of the male drum pins of the male embossing
drum 68 even after film sheet 20 has left the nip region 70. The
film sheet 20 may be preheated to aid in such permanent deformation
by radiant heating, conductive heating, convective heating or other
methods well known in the art.
[0075] At the nip region 70, in addition to being permanently
mechanically deformed by the embossing drums, the film sheet 20
also comes in contact with the adhesive 12 that is coated only on
the outermost diameter of the female embossing drum 64. Due to the
pre-coating on the outermost diameter of the female drum 64, the
adhesive adheres itself to the film sheet 20 in the spaces 28
between and around the film protrusions 26 that are formed through
permanent mechanical deformation by the embossing drums. This
results in a three-dimensional formed film sheet 20 with a layer of
adhesive 12 surrounding embossed, film stand-off protrusions 26
that have a greater height H than the thickness of the adhesive
X.
[0076] A method of bonding a film sheet 20 and a substrate 40 to
each other is shown in FIGS. 9 and 11. While the formed film sheet
20 is still integrally connected with the female embossing drum 64,
a substrate 40 is laid on the side of the film sheet 20 not in
contact with the female embossing drum 64. Before contact with the
film sheet 20, a laminating adhesive 30 is deposited on the
substrate 40 by a substrate adhesive deposition system 72 by slot
coating, or other methods well known in the art. While using a
pressure sensitive laminating adhesive 30 is the preferred method
to create the bond between the film and the substrate, other
methods, such as heat sealing or ultra-sonic welding may also be
used. After initial contact between the film sheet 20 and the
substrate 40, or at the point of contact, the film sheet 20 and
substrate 40 are joined by pressure from a pressure drum 74, in a
direction perpendicular to the plane of the film sheet 20 at that
point. Since the formed film sheet 20 is still integrally connected
with the female embossing drum 64 when the film sheet 20 and
substrate 40 are combined by the pressure drum 74, the film
protrusions 26 are protected from deformation under the pressure of
the pressure drum 74 by the patterned depressions in the female
embossing drum 64. These patterned depressions effectively surround
the film protrusions 26, thereby serving as a protective shell that
prevents the pressure drum 74 from collapsing the film protrusions
26. The substrate 40 and film 20, which are now bonded together,
are then stripped from the female embossing drum 64 by a stripping
drum 76.
[0077] The protrusion size, shape and spacing, the film flexural
modulus, and the film thickness determine the resistance of the
protrusions to collapse over a unit area. It is desirable to
provide a strength which is sufficient to withstand a pressure up
to about 4.4 pounds per square inch without collapsing protrusions
to where the adhesive contacts a target surface. This resistance to
collapse enables the composite material to be wound onto a drum
without damage for compact packaging purposes and to be handled and
repositioned without premature adherence to a target surface. A
composite material having the most preferred dimensions is believed
to provide the desired strength. While particular embodiments of
the present invention have been illustrated and described, it will
be obvious to those skilled in the art that various changes and
modifications may be made without departing from the spirit and
scope of the invention, and it is intended to cover in the appended
claims all such modifications that are within the scope of the
invention.
* * * * *