This invention relates to materials which are ink jet imprintable
and that can be used for adhesive image transfer, and constructions made with such
Background of the Invention
Labels, tapes and similar constructions are ubiquitous in modem society.
Many such constructions include a release liner coated with an adhesive, such as
a pressuresensitive adhesive (PSA), which is laminated to a paper or film face stock.
Removal of the release liner allows the construction to be adhered to a substrate.
The face stock and liner are a major cost of the label.
Many adhesives, such as those commonly used in label constructions,
are not water dispersible or repulpable.
Therefore, they make recycling of the label product difficult, due
to the tendency ofthe adhesives to form globules during the repulping process. In
addition, most PSAs are tacky when dry and cannot readilybe used with inkjet printers
that have become so popular in today's world. Moreover, such PSAs typically are
not hydrophilic, making it difficult to directlyprint on them directly with water-based
ink jet printer inks. Instead, only the face stock or liner is ink receptive. The
unsuitability of such PSAs for use in ink jet printers is compounded by the tendency
of the adhesives to block the printer ports in the printers.
Although attempts have been made to formulate moisture activated or
water activated adhesives, many of the adhesives produced have been rubber based
and, therefore, subject to oxidative and UV degradation. Other adhesives have been
solvent borne, and thus objectionable for environmental, health and safety reasons.
The following patents are representative. U.S. Patent No. 3,681,179 to Theissen
discloses a solar control film construction having a water-activatable adhesive
system comprising a normally tacky and pressure-sensitive adhesive coating covered
by a thin, tack-free continuous water-soluble layer. A tack free emulsion acrylic
adhesive is not disclosed.
European Patents Nos. 199,468 and 297,451 describe a method for compounding
water-activatable hot melt adhesives comprising polyaklylenimine or other vinyl
heterocyclic monomers, a hydroxy-substituted organic compound, a plastizier, tackifier,
and filler, and an antioxidant. No mention is made of making water activatable emulsion
U.S. Patent Nos. 4,331,576 and 4,325,581 to Colon et al. disclose
common water-soluble hot melt adhesives based on polymers containing vinyl pyrrolidone
and other heterocyclic monomers. Emulsion acrylics are not disclosed.
U.S. Patent No. 4,052,368 to Morrison and 4,172,824 to Harrington
describe water sensitive hot melt adhesives including polyester-based adhesives
which typically comprise a copolyester in combination with a plasticizier. The systems
are not emulsion acrylics.
None of the above-identified patents disclose or suggest the possibility
of making a hydrophilic, acrylic emulsion polymer that is non-tacky when dry and
water activated to become an adhesive, and that can be used in a "label-less" or
"liner-less" construction, i.e., a construction in which either a face stock or
liner is not required
GB A 2 243 332 describes a printing method which includes an ink image
forming step and an ink image retransferring step. In the ink image forming step,
an ink image (21) is formed on a hot-melting type adhesive layer (14) of a transfer
sheet (10) by using a heat-sensitive image transfer type recording device. In the
image retransferring step, the ink image (21) and the hot-melting type adhesive
layer (14) are transferred onto an image receiving member (30) such as a cloth by
heatedly pressing the transfer sheet (10).
US A 5 407 718 describes alabel sheet assembly for transparent paper
labels which has a substantially transparent paper label sheet with a substantially
transparent, pressure sensitive adhesive coating. Labels are die cut out of the
paper label sheet. The paper label sheet is mounted on a backing sheet, which has
a release coating to allow removal of the labels. The pressure sensitive adhesive
may be stable in the presence of temperatures up to 200 degrees Fahrenheit so that
the labels may be printed in a laser printer. The label sheet assembly may be printed
in its entirety by an ink jetprinteror xerographic printer with a resulting high
print quality. A method for printing transparent label sheet assemblies comprises
forming double thickness label sheet assemblies, creating a paper supply, feeding
label sheet assemblies from the paper supply through xerographic and ink jet printers,
removing labels from a backing sheet, and applying the labels to products to be
labeled. By using transparent paper labels, this method allows a single source of
transparent label sheet assemblies to supply a variety of different printers, including
ink jet, and xerographic printers.
Many arrangements for the transfer of images from ink jet printers
are known. For example, images, including printing, may be printed onto labels having
pressure sensitive adhesive on the labels, and these labels may be applied to a
desired substrate, such as a bottle or other product.
Summary of the Invention
Accordingly, the present invention provides a cold image transfer
method using no supplemental heat in the course of image transfer, comprising: forming
an image transfer sheet having the following layers: (a) a liner sheet; and (b)
an adhesive layer; applying an image to said image transfer sheet from an ink jet
printer; applying said image sheet to a substrate at ambient temperature with at
least a portion of said adhesive bonding directly to said substrate; and removing
In a preferred embodiment, a conventional inkjet printer is employed
to apply an ink image, preferably a colored image, to the adhesive layer of an image
transfer sheet, the adhesive layer having been coated onto a base layer which is
preferably flexible and nonporous to an inkjet printer ink. The non-porous flexible
layer may be a sheet ofplastic which can be either opaque or transparent.
The adhesive layer is compatible with and will absorb an inkjet printing
ink. Most inks used in inkjet printers are water based, but such inks may also be
based on organic solvents or carriers for the ink dyes and/or pigments. Thus, depending
upon the ink used in the inkjet printer, the adhesive layer may be either hydrophilic
or hydrophobic. Since, as noted above, most ink jet printing inks are water based,
it is generally preferable if the adhesive coating or layer, at the time of imaging,
is hydrophilic and will absorb the water-based ink.
Water-based inks for inkjet printers are well-known in the art and
therefore no detailed exemplification thereof will be given herein. These water-based
inks contain a sufficient amount of water to be the carrier for the dyes and/or
pigments in the ink. Of course, a waterbased inkjet printing ink may contain water-miscible
organic liquids such as polyhydric alcohols which are often present in water-based
inks to prevent clogging of the nozzles. The inks may also contain a variety of
other compounds such as surfactants, etc.
At the time of printing the ink on and into the adhesive layer to
form an image, the adhesive layer should be detackified. After the adhesive layer
is imaged, it will then be activated, i.e. the adhesive layer tackified to a tacky
state, and adhered or bonded to any desired substrate such as a ring binder, clothing,
notebook cover, a glass window, a wall or anywhere it is desired to view the image.
In this regard, it should be noted that if the image is placed or adhered to a non-transparent
substrate, and the base layer is not transparent, the adhesive layer should be releasably
bonded to the base layer so that the base layer can be removed to allow the image
to be seen by a viewer. From the foregoing, it is apparent that the image is viewable
from both the lower surface (i.e. the surface facing the base layer) and the upper
surface (i.e. the surface facing away from the base layer) of the adhesive coating
The ink absorbing adhesive layer used in the present invention may
be pressure sensitive, particularly hydrophilic pressure sensitive adhesives. Such
adhesives are known in the art and include repulpable pressure sensitive adhesives
such as those disclosed in U.S. Patent Nos. 5,196,504 and 5,326,644.
The adhesives disclosed in these patents are water-dispersible and
tacky at room temperature which make them ideal for use in the present invention.
Of course, other pressure sensitive hydrophilic adhesives are also known in the
art and they too are suited for use in the present invention.
If an adhesive is used which is tacky at the time when it is imaged,
the adhesive may be detackified by providing the imaging transfer sheet with an
outer detackifying layer over the upper surface of the adhesive coating. Such a
detackifying layer will be porous to the imaging ink so that a sufficient amount
of ink will pass through the porous detackifying layer to the adhesive layer to
allow an image to be formed therein. Generally speaking, the detackifying layer
will permit at least 30 percent and preferably more (e.g. 40 percent) of the ink
jet printing ink to pass into the adhesive layer and form an image.
Various types of porous detackifying layers may be used. For example,
a mesh coating such as cheesecloth may be used, preferably with a very thin layer
of release material such as silicone between the mesh layer and the adhesive, preferably
coated on the mesh before it is applied to the adhesive so that the mesh layer may
be more readily removed. It is emphasized that the silicone layer does not cover
the pores of the mesh, thereby allowing the ink to pass through the pores of the
mesh and into the pressure sensitive adhesive. Other mesh materials having finer
strains and being less coarse than cheesecloth may be employed. Even paper may be
employed since it is porous to the ink.
Other porous detackifying outer layers which are useful in the present
invention may be formed from finely divided particles uniformly dispersed on and
bonded to the surface of the tacky adhesive layer. Examples of such particles are
cellulose particles and dextrin particles. It is particularly preferred if the finely
divided particles have the shape of round spheres as is the case with starch particles
(e.g. corn or potato starch) and powdered polyvinyl alcohol. Such porous layers
are advantageous used with a pressure sensitive adhesive which, when heated, becomes
sufficiently fluid that when pressure is applied the particles are dispersed into
the adhesive layer, thus allowing the tacky adhesive layer to contact and adhere
to a suitable substrate. If the finely divided particles have substantially the
same refractive index as the adhesive layer (e.g. starch particles and polyvinyl
alcohol particles), the particles are not seen by a viewer and thus seem to disappear.
Exemplary of pressure sensitive adhesives which are well suited for use with the
finely divided particles are repulpable adhesives as described in the patents cited
above. It should be noted that powdered vinyl alcohol (whether in the form of round
spheres or not) is normally not tacky when dry, but is permeable to water so that
the ink jet image is readily absorbed into the PVA coated pressure sensitive adhesive.
Where this detackifying coating is used, it is desirable to wet or at least dampen
the substrate to which the image is subsequently applied, or the PVA surface, and
this serves to activate the adhesive and have the PVA combine therewith.
It is also noted that a release layer may be employed between the
adhesive and the non-porous, flexible, preferably transparent, backing sheet, so
that the backing sheet may be removed. When a hydrophilic adhesive is used and the
image sheet is adhered to a window, for example, it may be washed off by first removing
the transparent plastic sheet and then washing with soap and water in a normal manner.
In some other cases, it may also be desirable to remove the transparent
plastic layer, which may be mylar, for example, so that the image in the adhesive
appears brighter; and an additional transparent detackifying layer, which may be
polyvinyl alcohol, may be used between the release layer and the pressure sensitive
adhesive to eliminate the surface stickiness or tackiness of the adhesive, which
would otherwise be directly exposed. The detackifying layer need not be transparent,
however, and may include fine metallic flakes, phosphorescent material, fluorescent
material, fabric, leather, and/or other materials. The additional layer could also
provide water proofing if comprised of urethane, varnish, or other water resistant
It is also noted that the pressure sensitive adhesive layer may be
a delayed action, heat activated pressure sensitive adhesive wherein the pressure
sensitive adhesive properties arise following heating and have a predetermined open
tack time for adhering to surfaces, and then become non-tacky. When such a pressure
sensitive layer is employed, a detackifying layer would not be needed. Examples
of such adhesives include acrylates and ethylene vinyl acetate.
In accordance with another aspect of the invention, the upper layer
of the image sheet may be a water activatable adhesive. In further accordance with
the present invention, there are provided hydrophilic, repulpable, acrylic polymers
which are non-tacky when dry but become tacky when wet, and which exhibit high peel
strength and excellent adhesion to a diverse array of substrates, including paper,
polymer films, and highly polar substrates such as stainless steel and glass. In
one embodiment of the invention, the composition comprises an acrylic-based polymer
prepared by emulsion polymerization of a monomer mixture comprising, based on the
total weight of monomers, from about 40 to about 70% by weight of one or more alkyl
acrylates, the alkyl group of which has from 4 to about 8 carbon atoms; from about
10 to about 20% by weight of methyl acrylate; from about 2 to about 15% by weight
of vinyl acetate; from about 10 to about 25% by weight of methacrylic acid and/or
acrylic acid and a positive amount up to about 30% by weight, of methyl methacrylate.
In another embodiment, the monomer mixture additionally contains a positive amount,
up to about 5% by weight, of a short chain hydroxyalkyl methacrylate, such as hydroxyethyl
methacrylate. Unexpectedly, the presence of methyl methacrylate appears to enhance
the "clean break" between water-activated regions of the polymer layer and non-activated
regions, a phenomenon described below.
The acrylic emulsion polymers of the present invention have a relatively
high glass transition temperature (Tg) -- as high as about 40°C, for
some formulations -- and a weight average molecular weight of from about 100,000
to about 200,000. Because of their high glass transition temperatures, the polymers
are not tacky at room temperature, when dry. But the polymers are highly polar and,
when exposed to moisture, such as the water in an aqueous ink jet printer ink, they
become tacky. The polymers are hydrophilic and repulpable, water-activatable and
transparent to visible light. They may be directly printed upon using a water-based
ink, and after activation and adhesion to a substrate can be removed from a substrate
by application of water. They are particularly useful as ink jet-imprintable polymers
converted into adhesives used in a variety of constructions, including "label-less"
or "liner-less" labels, security films, solar control films, beverage labels (where
it is desirable to have a transparent label on a clear bottle), decorative adhesive
image sheets, and the like.
This adhesive may be coated onto the flexible base layer, with an
intermediate release coating, if desired. The resulting image transfer sheet is
non-tacky when dry. However, the upper adhesive layer is hydrophilic, and will absorb
an image from a conventional ink jet printer. Upon printing with the ink jet printer,
the solvent present in the inks penetrates the mixture of PCA and polyacrylic acid
causing the mixture to become tacky again, where the ink has been printed. The areas
where ink has been printed will remain tacky until the ink solvent has evaporated.
It is desirable to apply the image to the substrate while the printed areas are
still tacky because once the ink has evaporated, the image sheet will again become
non-tacky. However, if the ink dries, either the image sheet or the substrate, such
as a window, may be sprayed or dampened with water to activate the adhesive so that
the image sheet will adhere to the substrate.
In accordance with an improved embodiment of the present invention,
an assembly for transferring ink-jet printed images has an adhesive layer in between
a non-tack upper surface and a flexible substrate. The adhesive layer has discrete
zones separated from one another along boundaries. The adhesive layer may either
be printed in small dots, or may be printed as a continuous layer and then scored
to form the discrete zones.
The user first prints an image onto the assembly with an ink jet printer,
then places the upper layer of the assembly against an image-receiving surface.
The user peels the assembly back from the image-receiving surface, thereby leaving
the image on the image-receiving surface. The zones of adhesive into which ink jet
printer ink has not been printed remain adhered to the flexible substrate, while
the ink-bearing zones of adhesive attach to the image-receiving surface. This allows
the image to break cleanly from the image sheet, which otherwise is prohibited by
the cohesion of the acrylic adhesive layer.
In another aspect of the invention, an ink jet-imprintable, water-activated
adhesive construction is provided. In one embodiment, the construction comprises
a layer of water-activatable acrylic polymer, coated on a flexible substrate, which
in some embodiments is a release liner, such as an inherently releasable film or
a paper or film backing coated with a silicone or other release material. The water-activatable
layer is non-tacky when dry, but becomes tacky when exposed to water. Consequently,
when printed with a water-based ink jet printer ink, the polymer layer becomes tacky
within the region of the printed image, but not in regions not printed on. When
applied to a substrate, this allows a clean break between imaged (printed) and unimage
(unprinted) regions of the adhesive, and the ability to form a "label-less label."
The construction is useful as a label or decorative image sheet, and
is applied to an object or surface by adhering the water-activated polymer (which
is now tacky) to the object and, optionally, removing the flexible substrate. In
one embodiment, the construction includes a water insoluble, transparent film layer,
preferably of a polymeric material, disposed between the water-activatable polymer
and a release liner. Alternately, the water insoluble layer is used in place of
the release liner, as a flexible substrate.
Other objects, features and advantages of the invention will become
apparent from a consideration of the following detailed description and from the
Brief Description of the Drawings
Fig. 1 is a schematic cross-sectional view of an imaging sheet illustrating
the principles of the present invention;
Fig. 2 shows an ink jet printer receiving an imaging sheet of the type shown
in Fig. 1;
Fig. 3 shows a sheet illustrating the principles of the invention in which a
porous screen is being removed;
Fig. 4 shows the image sheet of Fig. 3 mounted on a transparent substrate, such
as a window, and in the process of having the support layer peeled off;
Fig. 5 shows a further embodiment of the invention in which a coating of starch
is employed as the detackification coating;
Fig. 6 shows an embodiment of the invention in which a water activated adhesive
imaging layer is employed;
Fig. 7 shows an alternative embodiment of the present invention having a plurality
of discrete zones defined by printed dots;
Fig. 8 shows an alternative embodiment similar to the embodiment of Fig. 7,
except that the upper and lower layers are continuous;
Fig. 9 shows an alternative embodiment that is similar to the embodiment of
Fig. 7, except that the discrete zones are defined by score lines or die cuts;
Fig. 10 shows an alternative embodiment that is similar to the embodiment of
Fig. 9, except that the upper and lower layers are continuous;
Fig. 11 illustrates a version of the embodiments of Figs. 7-10 having a transparent
substrate for purposes of illustration, in which discrete zones of the assembly
bearing the ink that defines star images adhere to the image-receiving surface,
while discrete zones of the assembly that do not bear the ink do not adhere to the
Fig. 12 is an alternative embodiment having a continuous upper face, and having
a layer in between the adhesive and the substrate that serves to protect the image-bearing
zones of adhesive after transfer to the image-receiving surface;
Fig. 13 is a detail view of the embodiment of Fig. 12, after an ink jet printer
has printed an image into the adhesive, and after a user has first applied the upper
face of the printed assembly to an image-receiving surface and then has removed
the assembly from the image-receiving surface, thereby leaving on the surface the
discrete zones that bear the image, but leaving on the assembly the zones of adhesive
that do not bear the image;
Fig. 14 is an alternative embodiment similar to the embodiment of Fig. 7, except
that there is no non-tack layer in between the adhesive layer and the substrate;
Fig. 15 is a schematic illustration of the configuration and use of one embodiment
of an ink jet-imprintable, water-activated construction prepared in accordance with
the present invention; and
Fig. 16 is a schematic illustration of the configuration and use of a second
embodiment of an ink jet-imprintable, water-activated construction prepared in accordance
with the present invention.
Detailed Description of the Preferred Embodiments
Referring now to the drawings, Fig. 1 is a cross sectional view of
an imaging sheet 12 in which the image is held in an ink absorbent pressure sensitive
adhesive layer 14. The imaging sheet 12 may be provided with a support layer 16
which is preferably transparent and may be formed of a plastic material such as
Mylar. The Mylar layer 16 may, for example, have a thickness of between about 0.0127
mm (one-half of one thousandth of an inch) to about 0.0762 mm (0.003 inch). Coated
on the support layer 16 is a release layer 18 which is normally a material such
as silicone, having a thickness of about 0.00254 mm (0.0001 inch). An optional detackifying
layer 42 such as polyvinyl alcohol may be provided, having a thickness ofabout from
0.00127 mm (0.05 mils) to 0.00381 mm (1.5 mils). Thepressure sensitive adhesive
layer 14 may, for example, have a thickness of between 0.0127 mm and 0.0508 mm (S
and 2 mils). A detackifying layer 20 is provided at the upper surface of the imaging
sheet 12, and this layer may be a porous screen material, such as a cheese cloth,
or a fine open mesh. To facilitate removal ofthe porous layer 20, it maybe sprayed
with a release coating 22 prior to its application to form the complete composite
imaging sheet 12. The mesh screen may, for example, be from 0.00254 mm to 0.0127
mm (1 to 5 mils) thick, and the release layer may, again, be formed of silicone
and is a very thin coating in the order of 0.00254 mm (one ten thousandth of an
inch) in thickness.
Fig. 2 of the drawings shows a conventional ink jet printer 32 through
which the composite imaging sheet 12 is being fed. Incidentally, the mesh as shown
in Fig. 2 on the imaging sheet 12 is shown as being much coarser than the mesh or
screenwould actually be in practice. For example, the mesh or screen could have
transverse threads spaced in the order of 0.0254 mm or a few hundreds of mm (a thousandth
or a few thousandths of an inch) apart in each direction, rather than the very coarse
mesh as shown in Fig. 2.
Referring now to Fig. 3 of the drawings, the mesh 20 is in theprocess
ofbeing removed, and the imaged pressure sensitive adhesive layer 14 will then be
on the upper surface of the sheet 12. The adhesive layer 14 will still be supported
by the underlying plastic sheet, as indicated by the reference numeral 16.
Fig. 4 is a schematic showing of the pressure-sensitive adhesive layer
14 mounted on a sheet of glass 36 shown in a frame 38 which could, for example,
be a window frame in which the sheet of glass 36 is mounted. In Fig. 4, the transparent
sheet 16 is shown being removed. In this regard, it is noted that the image in the
pressure-sensitive adhesive layer 14 is clearly visible from the other side of the
glass, but is less clear when it has to be viewed through the Mylar™ layer
16. Accordingly, in order to more clearly view the image in the layer 14, the protective
substrate or transparent plastic layer 16 may be removed, once the sheet has been
adhered to the glass 36. In addition, following the removal of the layer 16, which
may serve as a protection against moisture for the hydrophilic layer 14, the entire
window may be readily washed clean with soap and water.
Incidentally, following removal of the protective layer 16, it is
sometimes preferred that the pressure sensitive adhesive layer 14 not be sticky,
or tacky. Accordingly, as shown in Fig. 1, an additional detackifying layer 42 may
be provided. This detackifying layer may, for example, be polyvinyl alcohol. This
layer could also include fine metallic flakes, or phosphorescent material, or fluorescent
material, or fabric, or leather, etc. so that the end user could simply print an
image to be transferred and then, upon transferring the image, the detackifying
layer (comprised of the previously mentioned materials) would now be the only layer
visible to the user. This allows the end user to expand the use of a typical ink
jet printer, from two dimensional visual representations in inks, to visual representations
in the previously mentioned substances. The additional layer could also provide
water proofing if comprised of urethane, varnish, or other water resistant material.
With this layer in place, when the base layer 16, as shown in Fig. 4, is removed,
the image bearing pressure-sensitive layer 14 will not be directly exposed, and
therefore will not feel tacky.
As an alternative to the use of pressure sensitive material having
normal, fairly long lasting adhesive properties, a delayed action heat activated
pressure sensitive adhesive may be employed. One such adhesive is available from
the Nashua Company of Nashua, New Hampshire under the trade designation number BM-4.
Inks for use with this adhesive should have a polar solvent or carrier, such as
methylethyl ketone. Such adhesives are heat activated and have an open sealing or
adhesive time period during which they may be applied to a substrate, and thereafter
they become non-tacky. When such adhesives are used, the additional detackifying
layer 42 is not needed, and a simplified overall construction as shown in Fig. 6
may be used.
Concerning the various layers of Fig. 1, the basic components of the
sheet 12 include the support layer 16, the ink absorbing pressure-sensitive adhesive
layer 14, and a detackifying layer 20. Concerning the release layer 18 and the detackifying
layer 42, these will not be included in the sheet in the event that it is not desired
to remove the transparent support layer 17. In addition, in some cases, the release
layer 22 may not be needed, when the mesh can be peeled off the adhesive layer without
release layer 22, or when a different type of detackifying layer, as disclosed hereinbelow,
Also, instead of a hydrophilic adhesive for the pressure-sensitive
adhesive layer 14, other types of pressure-sensitive adhesives may be employed for
use in connection with an organic solvent based ink, which will be absorbed by,
and permit an image to penetrate the particular pressure-sensitive adhesive which
For specific examples, solvent cast acrylic pressure sensitive adhesives
or hot melt pressure sensitive acrylic adhesives may be used. For such adhesives,
inks having relatively polar solvents such as normal butyl alcohol or methylethyl
ketone are preferred. Rubber based pressure sensitive adhesive such as Avery S-246
maybe employed with inks in relatively low polarity solvents such as heptane or
Referring now to Fig. 5 of the drawings, Fig. 5 shows a sheet 12'.
In Fig. 5, the base or support layer 16', the release layer 18', the detackifying
layer 42', and the ink absorbing pressure sensitive adhesive layer 14' are as described
However, instead of a mesh type detackifying layer at the upper surface,
Fig. 5 discloses the use of starch particles as the detackifying coating 54. When
a starch detackifying layer 54 is employed, the ink solvent causes the starch particles
to dissolve and intermix with the underlying adhesive layer. The result is that
only the area where the ink jet image has been printed becomes tacky. The rest of
the sheet remains non-tacky and does not transfer. However, heat and pressure can
also be employed to combine the starch layer with the adhesive and therefore activate
the adhesive layer 14' so that it is tacky and will stick to whatever surface is
employed. As noted previously, the starch particles have substantially the same
refractive index as the adhesive and therefore when combined with (dispersed in)
the adhesive the particles cannot be seen.
Referring again to Fig. 1 of the drawings, the detackifying layer
may be a very thin layer of polyvinyl alcohol (PVA), preferably a fraction of 0.0254
mm (thousandth of an inch) thick, or even about 0.00254 mm (0.0001 inch) thick,
or about 2 grams/m2. PVA is non-tacky when dry, but is hydrophilic so that an applied
ink jet image will penetrate through to the underlying hydrophilic adhesive layer.
Printing ofthe ink jet ink causes the PVA layer and the underlying adhesive layer
to intermix, allowing only the printed image to become tacky. As the image sheet
is applied to a substrate the substrate or the image sheet is dampened, the PVA
further combines with the pressure sensitive adhesive and a good adhesive bond is
obtained between the imaged pressure sensitive adhesive and the substrate.
Now, turning to Fig. 6 of the drawings, a relatively simple embodiment
of the invention includes the base layer 62, a thin release coating 64, and a water
activatable adhesive layer 66. Layer66 may be a few hundredths ofamm (thousandths
of an inch) thick, for example, 0.051 mm to 0.127 mm (0.002 to 0.005 inch) thick.
The water activated adhesive layer 66 maybe formed of polyvinyl alcohol
(PVA) and polyacrylic acid. It may be applied as an aqueous solution including about
10 percent solids, with approximately 75% PVA and 25% polyacrylic acid. The coating
is non-tacky when dry. However, it is hydrophilic, and accepts a good image from
an ink-jet printer. Following imaging the image sheet may, for example, be adhered
to a substrate, such as a window which has been sprayed with water, so that when
the image sheet is applied to the wet window the adhesive is activated, and the
image sheet is adhered to the window. Thereafter, the base layer may be peeled off,
leaving the imaged adhesive layer on the substrate.
The present invention provides acrylic polymers that are non-tacky
when dry, hydrophilic, water repulpable, and water activatable to become tacky --
even by a small amount of moisture. When activated bywater, the polymers become
tacky. When applied to a substrate, the activated adhesives exhibit high peel strength,
yet are removable by further application of water. Advantageously, the adhesives
are ink jet imprintable, as well as transparent to visible light.
In one embodiment ofthe invention, the activatable composition comprises
an emulsion polymer formed from a monomer mixture comprising, based on the total
weight ofmonomers, (a) from about 40 to about 70% by weight of at least one alkyl
acrylate, the alkyl group of which has from 4 to about 8 carbon atoms; (b) from
about 10 to about 20% by weight of methyl acrylate; (c) from about 2 to about 15%
by weight of vinyl acetate; (d) from about 10 to about 25% by weight of methacrylic
acid, acrylic acid, or a mixture of methacrylic and acrylic acid; and (e) a positive
amount -- up to about 30% by weight based on the total weight of monomers -- of
methyl methacrylate. In another embodiment, the monomer mixture further comprises
(f) a positive amount -- up to about 5% by weight -- of a short chain hydroxyalkyl
methacrylate. Both embodiments are highly polar, and the polymers are hydrophilic.
The identity and relative amounts of monomers used to form the polymers
are selected such that the polymer has a high enough glass transition temperature
Tg, and/or other properties (e.g., high plateau modulus) that the polymer
is non-tacky at room temperature, when dry. To that end, it is preferred to maximize
the relative amounts of methyl methacrylate, vinyl acetate, and/or the acid monomers,
relative to the amount of alkyl acrylate(s) used.
Thus, in one preferred embodiment, the monomer mixture includes at
least 5%, preferably 10%, by weight of methyl methacrylate, and the polymer Tg
can be as high as about 40°C. In another embodiment, as much as 20%, or even 30%
by weight of methyl methacrylates is included, in order to increase polymer Tg
and improve the "clean break" feature of the water-activated adhesives. In other
embodiments, however, the amount of methyl methacrylate may be much lower -- as
well as even 0.1% by weight -- and Tg of the polymer is raised through
the effect of other monomers.
It is also preferred to employ a mixture of alkyl acrylates as the
first monomeric component. Useful alkyl acrylates include n-butyl acrylate, 2-ethylhexyl
acrylate, isooctyl acrylate, and the like. A mixture of 2-ethylhexyl acrylate and
butyl acrylate is preferred. Similarly, it is preferred to employ a mixture of acrylic
and methacrylic acid as the fourth monomeric component of the polymer.
In those embodiments where a hydroxyalkyl methacrylate monomer is
employed, the monomer has a short chain alkyl group containing from 2 to about 6
carbon atoms, with hydroxyethyl methacrylate (HEMA) being preferred. The amount
of HEMA that can be employed is limited by its effect on viscosity and pre-emulsion
stability. In general, the concentration is kept below about 5%, more preferably
about 4%, based on the total weight of monomers.
The acrylic polymers of the present invention are prepared in a conventional
manner, using unreactive surfactants or, more preferably, a mixture of unreactive
and reactive surfactants, the latter copolymerizing with the monomers and becoming
part of the emulsion polymer. Representative conventional surfactants include anionic
surfactants such as Polystep B-27, an aqueous solution of the sodium salt of nonylphenoxy
polyethyleneoxyethanol sulfate, available from Stepan Company (located in Winnetka,
Illinois); nonionic surfactants such as AR 150, a nonionic ethyleneoxide adduct
of pale wood rosin, available from Hercules, Inc. (located in Wilmington, Delaware);
and mixed anionic/nonionic surfactants, such as Polystep J-927, a mixture of Polystep
B-27 and Polystep F-9 (nonylphenol ethoxylate), also sold by Stepan Chemicals. Up
to about 10% by weight of surfactants is typically added. Good repulpability has
been obtained with 8% surfactants, as measured by TAPPI UM 213.
Preferred reactive surfactants are anionic vinyl functional surfactants,
such as sodium vinyl sulfonate and sodium styrene sulfonate. Reactive surfactants
tend to enhance cohesive strength of the resulting copolymer, and aid in the copolymerization
process. When used, reactive surfactants are typically employed in an amount of
between about 0.5% and 1.5% by weight, preferably about 1%, based on the total weight
Polymerization initiators or catalysts are advantageously added to
speed the copolymerization of the monomers. Useful polymerization initiators include,
without limitation, tert-butyl hydroperoxide (t-BHP) and potassium persulfate (KPS).
In some embodiments, a molecular weight regulator is added to the monomer mixture
to control average polymer chain length. Useful regulators include n-dodecyl mercaptan
(n-DDM) and similar compounds. Other agents and additives can be added to facilitate
more efficient, controlled emulsion polymerization, including oxidants such as hydrogen
peroxide and iron ethylenediaminetetraacetic acid (Fe EDTA), reducing agents such
as sodium formaldehyde sulfoxylate (available from Henkel Company), and post-polymerization
agents such as ascorbic acid. Ascorbic acid forms a redox system with t-BHP (which
is an oxidant), and facilitates removal of residual monomers after polymerization).
Before filtering the reaction mixture, a biocide, such as Kathon LX (available as
a 1.5% solution from Rohm & Haas) can be added to prevent bacterial growth.
The emulsion polymers are prepared with excellent conversions at a
reaction temperature of around 70°C, in the presence of from about 0.5 to about
1% by weight, based on the weight of the monomers, of a persulfate or equivalent
catalyst, with the monomer mixture being fed over a period of about 2-4 hours. Reaction
pH preferably is regulated by addition of sodium bicarbonate, or similar agents,
to within a range of from about 4.0 to about 6.0.
While actual production techniques may vary depending upon particular
monomer compositions, available equipment, and other considerations, in general,
the emulsion polymers are prepared by first mixing one or more pre-emulsions containing
conventional surfactants, sodium bicarbonate, and some or all of the monomers in
deionized water; adding reactive surfactants and other reactor ingredients (e.g.,
Fe EDTA, AR 150, hydrogen peroxide) to a reactor under nitrogen; heating the reactor
to 700C + 20C and then adding a pre-emulsion charge, over time (preferably in stepped
or mixed feed sequences); adding an initiator charge containing, for example, potassium
persulfate; continuing the pre-emulsion feeds and addition of any accelerators;
adding any post-reaction charges (e.g., t-BHP, ascorbic acid, and more water); cooling
the reactor contents to below 35°C adding the biocide; and filtering the emulsion
Using the emulsion polymerization techniques described above, several
exemplary embodiments of the present invention were prepared. The monomeric compositions
ofthe emulsion polymers are presented in Table I. Examples 1A-1H contain alkyl acrylates,
methyl acrylate, vinyl acetate, a mixture of methacrylic acid and acrylic acid,
and methyl methacrylate. Example 2 additionally contains hydroxyethylmethacrylate.
Pilot scale-up of Example 1E yielded an emulsion PSA polymer with a solids content
ofabout 58%, a viscosity of about 200 mPa·s (20 PI) (200 cP), and a pH of about
5.5. One percent by weight of n-DDM was used as a chain transfer agent in a pre-emulsion
used to prepare the polymer.
Using standard Pressure-Sensitive Tape Council (PSTC) test procedures,
90° peel, loop tack and shear were measured for Example 2F, (after activation with
water), applied at a coat weight of 20 grams per square meter.
Static shear from stainless steel was measured using a 12.7 mm x 12.7
mm (1/2" x 1/2") test area on longer test strips. 90° peel and loop tack were measured
from stainless steel, high density polyethylene (HDPE), glass, and corrugated board
The results are presented in Table II, where the observed adhesion
failure modes -- face stock failure (FS) and panel failure (P) -- are given in parentheses.
An alternative class of embodiments utilizes an adhesive layer that
is subdivided into individual zones that can be removed from the release coated
backing sheet independently of one another. Figure 7 illustrates one such embodiment,
which is constructed as follows. A substrate 116 is coated with a release coating
118. A thin layer of PVOH 142 is set down on the release-coated substrate 116 in
small dots or zones 170 and is dried. Then, a layer of emulsion adhesive 114 is
applied to the PVOH layer 142 in small dots and dried. Finally, an outer layer of
PVOH 112 is applied to the adhesive layer 114 in dots and dried.
The outer layer of PVOH 112 provides a non-tack outer surface to prevent
the assembly from sticking to the interior of the ink-jet printer during printing.
The outer layer of PVOH 112 should be very thin, to ensure that as much ink as possible
passes through the PVOH layer during printing, while still maintaining a non-tack
The dots of adhesive and PVOH can be printed with a process employing
a Gravure wheel, in which dots have been etched. It is known in the art to print
lines of adhesive using a Gravure wheel into which lines have been etched. To print
dots rather than lines, dots are etched into the Gravure wheel rather than lines.
Fig. 8 is one presently preferred embodiment having a substrate 116
that is coated with a release coating 118. A thin, continuous layer of PVOH 142'
is set down on the release-coated substrate 116 and is then dried. Next, a layer
of emulsion adhesive 114 is applied to the PVOH layer in small dots, preferably
smaller than 1 millimeter in diameter, and then dried. Finally, a continuous outer
layer of PVOH 112' is applied to the adhesive layer 114 and dried. The embodiment
still has an adhesive layer that is subdivided into individual zones, each of which
can be removed from the release coated backing sheet independently of one another.
This overcomes the cohesive forces present in the adhesive layer, allowing the zones
bearing the printed image to be transferred to the substrate while the zones not
activated by ink jet printer ink remain on the assembly.
A presently preferred alternative version of the embodiment of Fig.
8 has a PVOH layer 142' that is continuous and that has a density of about 2 grams/m2
(gsm). The next layer 114 consists of a very aggressive hydrophilic repulp adhesive
that will be printed in dots 170 via gravure at a coat weight of around 35 - 45
grams/m2. The outer layer 112' will be continuous and consist of a layer
of non-tack repulp adhesive that is as thin as possible, preferably less than 2
Fig. 9 shows an alternative to the embodiment of Fig. 7, in that the
PVOH layers 112 and 142, and the adhesive layer 114 are initially applied in continuous
layers. The PVOH and adhesive layers are then divided into discrete zones 170 by
way of score lines, die cuts, or other lines of weakness.
To use the assembly, the user feeds the assembly into an ink-jet printer,
which prints a pattern onto the PVOH layer 112. Most of the ink passes through the
non-tack PVOH layer 112 and into the ink-absorbent, repulpable adhesive layer 114.
The liquid ink activates the adhesive, making the adhesive tacky in the area of
the printed pattern.
Fig. 10 shows an alternative to the embodiment of Fig. 8, in that
the adhesive layer 114 is first applied as a continuous layer rather than in dots.
The continuous adhesive layer is then divided into discrete zones 170 by way of
score lines, die cuts, or other lines of weakness. The upper and lower layers 142'
and 112', respectively, are both continuous layers.
Turning now to Figure 11, after printing the user presses the sheet
onto an image-receiving surface 172, then peels away the release-coated substrate
116. The lines of weakening (not shown) in the adhesive layer 114 permit the now-tacky
portions 174 of the adhesive to remain on the surface, along with the corresponding
portions of the PVOH layers 112 and 142 (not shown, but see Fig. 7). However, the
portions of the adhesive 176 that do not bear the printed image, along with the
corresponding portions of the PVOH layers 112 and 142, will not stick to the image-receiving
surface because the areas of the adhesive 176 outside of the printed pattern do
not become tacky.
Referring to Fig. 12, it is preferred that the outer layer of PVOH,
which forms the upper face of the assembly, is applied in a flat, continuous coating
112'. Otherwise, the ink jet printer ink will tend to seep through the outer PVOH
layer at boundaries of the dots or at the lines of weakness, giving the printed
pattern a hatched, jagged appearance. The image quality is significantly improved
by having a continuous upper face 112', which may also be called an outer layer,
so that the lines of the printed pattern may seep through unimpaired to the adhesive
Fig. 13 shows that even when the upper face 112' is continuous rather
than separated into zones, only the portions of the upper face 112' that are directly
adjacent to the image-bearing zones of adhesive will transfer to the image-receiving
surface. That is, the upper face 112' is thin and weak, and it does not prevent
the adhesive from separating from the assembly in zones. Furthermore, the liquid
ink jet printer ink activates the image-bearing zones of adhesive, which adhere
to the image-receiving surface despite the non-tack upper face 112'.
The bottom layer of PVOH 142' is a non-tack layer that prevents dust
and other particles from attaching to the tacky adhesive layer. So, for instance,
the user may transfer an ink-jet printed image from the assembly to the outer surface
of a three-ring binder, which is frequently stored against other binders and/or
books and papers. The non-tack PVOH surface prevents the image from sticking to
the other binders and/or books and papers.
The bottom layer ofPVOH 142 also serves to protect the printed image
from being easily rubbed off. The PVOH is water soluble, such that the user may
wash the image off of the image-receiving surface 172, if desired.
However, instead of using a PVOH layer 142 between the adhesive and
the substrate, a layer of water-resistant compound, such as an acrylic or other
material, can be used to repel water. This can be useful in protecting the image-bearing
adhesive layer from liquid spills, rain and so on. Alternatively, a high gloss compound
may be used in place of the PVOH layer 142 in order to give the image a high gloss.
Figure 14 shows a further alternative embodiment of the discrete-zone
type of assembly, in which there is no bottom non-tack layer 142. The embodiment
of Figure 14 is not presently preferred, as there is no layer to protect the image-bearing
zones of adhesive once the adhesive is applied to a surface. However, this embodiment
maybe less expensive to manufacture, since there is one less layer of PVOH, and
the construction may be useful in certain applications.
Ideally, the discrete zones of the embodiments of Figs. 7-14 will
be as small as possible. For example, the diameter of the dots of Fig. 7 will typically
be 0.0127 mm (S mil) or less. Similarly, the lines or boundaries forming the fine
grid of Fig. 9 will typically be spaced 0.0127 mm (S mil) or less from one another.
However, the dots must be properly sized in order to maintain a sufficient adhesive
density. Tests have found that the image quality is very unsatisfactory when the
adhesive is less than 10 grams per square meter; marginally satisfactory at 20 grams
per square meter; and excellent at 35 grams per square meter. So, as a practical
matter, the density of the adhesive should be at least 10 grams per square meter,
and preferably 25-35 grams per square meter.
The substrate 116 is typically polystyrene. Alternatively, a polyester
layer such as Mylar™ may be used, although polyester is currently more expensive
than polystyrene. Polystyrene also tends to perform better in ink jet printers.
The substrate may also be clear as, for instance, in the embodiment of Fig. 11.
Yet another embodiment employs a detackifying layer 112 other than
PVOH, such as finely divided particles uniformly dispersed on and bonded to the
surface of the tacky adhesive layer. Examples of such particles are cellulose particles
and dextrin particles. It is presently preferred that the finely divided particles
have the shape of round spheres as is the case with starch particles (e.g. corn
or potato starch) and powdered polyvinyl alcohol. As a further alternative to PVOH
layer 112, a porous screen material, such as a cheese cloth, or a fine open mesh,
may be used.
Figs. 15 and 16 are schematic illustrations of the configuration and
use of two different embodiments of an imprintable, water-activatable adhesive construction
prepared in accordance with the present invention. Referring to Fig. 15(a), an imprintable
adhesive construction 212 includes a layer of water-activatable polymer 214 coated
on or otherwise applied to a release liner 216. The polymer layer 214 has an inner
face 214a and an outer face 214b, and preferably comprises a water-activated acrylic
emulsion polymer as described above. The polymer layer is non-tacky when dry, but
hydrophilic, water-activatable, and ink absorbent--i.e., imprintable. Alternatively,
the polymer layer 214 is some other water-activated material, such as a mixture
of approximately 75% polyvinyl alcohol (PVOH) and 25% polyacrylic acid. In each
case, the polymer is applied to the release liner in a conventional manner, then
dried to form a thin film-like layer 214.
The release liner 216 has a conventional nature and may comprise,
for example, a paper or other flexible plastic backing, such as a Mylar™ film,
coated with a release material, such as polydimethylsiloxane, another silicone,
or a non-silicone material, such as polyvinyl octadecyl carbamate. Alternatively,
the release liner can comprise a film of inherently releasable material. Some polymer
films have a sufficiently low shear modulus to be useful as release liners without
the use of a release coating. (See, for example, U.S. Patent No. 4,339,485). The
release liner 216 has an inner or "front" face 216a (sometimes called the "release
face") and an outer or "back" face 216b.
It will be appreciated that the thicknesses ofthe respective layers
214 and 216 are grossly exaggerated in the figures. In practice, the constructions
maybe prepared as thin sheets or rolls, like asheet oflabels where, for example,
the polymer layer 214 has a thickness ofbetween 0.0127 mm and 0.051 mm (0.5 and
2 mils), and the release liner or other release carrier has a similar small dimensional
When the construction 212 is dry, it is non-tacky. However, it is
both hydrophilic and water-activatable, the latter meaning it becomes tacky when
exposed to water -even a small amount of moisture, such as the water in a water-based
ink. In Fig. 15, water-based ink 220 is ejected from a printer port 218 and forms
a printed image 225 on the outer face 214b at the polymer layer. The water in the
ink activates the polymer making it tackywithin the region of the printed image.
This is shown in Fig. 15(b), where a cross-sectional view of the construction is
depicted, and in Fig. 15(c), where a perspective view of the printed construction
The parts ofthe polymer layer not exposed to ink remain untacky, and
are designated as non-tacky or nonactivated regions 222. The formation of printed
image 225 causes tacky regions 224 to form in the polymer layer. Because the polymer
layer 214 is both thin and hydrophilic, it becomes activated across its entire cross-sectional
thickness, from the outer face 214b to the inner face 214a. Thus, although printed
on its outer face, it becomes tacky all the way through to the inner face.
The printed image 225 can be transferred directly to an object by
simply removing the release liner and pressing the delaminated construction (which
now consists of the adhesive layer 214 only) onto a surface, such as the window
230 depicted in Fig. 15(e). Alternatively, the release liner can be removed after
the adhesive layer is adhered to a surface or object. In one embodiment, only the
imaged (printed) region becomes affixed to the object, that is, the water-activated
regions 224 of the polymer layer (which are essentially coextensive with the imaged
region) adhere to the object, and the remaining, nonactivated (non-tacky) regions
222 of the polymer layer can be easily pulled away and discarded. The effect is
similar to application of a die-cut label, but appears to the eye as a "label-less"
printing on the object or substrate. This can result, for example, from the intrinsic
internal cohesiveness of the polymer, and/or the manner in which the adhesive was
applied to the release liner.
In one embodiment, the polymer simply has an internal cohesiveness
or integrity which is sufficiently low to afford easy detachability of nonactivated
regions from activated regions. This has been observed, for example, in constructions
made with a formulation that includes methyl methacrylate in the polymer backbone,
such as Examples 1A-1H and 2, above. Unexpectedly, the presence of methyl methacrylate
in the monomer composition appears to improve the clear break between activated
and nonactivated regions of the polymer during image transfer, allowing the nonactivated
regions to remain attached to the flexible substrate or liner, or simply discarded.
Alternatively, if the construction 212 is formed by applying the polymer 214 to
the release liner 216 as a micro array of slightly separated droplets or dots, it
is easy to strip the nonactivated regions 222 from the activated regions.
In another embodiment (shown in phantom in Fig. 15(e)), the nonactivated
regions 222 of the adhesive layer remain attached to the activated regions 224 (which
are coextensive with the image). The image 225 is adhered to the object by the activated
adhesive regions 224, but the nonactivated regions 222 remain secured as well, though
not adhesively bound to the object.
Once applied to a surface, the adhesive forms a high peel strength
bond. Yet, because the adhesive is water-dispersible, repulpable and hydrophilic,
it can be easily removed by application of water.
Referring now to FIG. 16, a schematic illustration of a different
configuration of an imprintable, water-activated construction, and its use, is depicted.
The construction 212' is similar in many ways to construction 212 of FIG. 15, and
similar components are numbered as in FIG. 15. In the construction 212' of FIG.
16, however, there is also provided a layer of water insoluble or water-resistant
material 226, having an inner face 226a and an outer face 226b, sandwiched between
the layer of water-activatable polymer 214 and release liner 216. This construction
is similar in most respects to that shown in FIG. 15, and its components have, for
example, similar small dimensional thicknesses.
The water-resistant layer 226 can be opaque but, more preferably,
is transparent, and can be formed, for example, of a polymeric material, such as
Mylar™, or a similar flexible, durable, water insoluble material. Multilayer
construction 212' is prepared in a conventional manner, for example, by laminating
a release liner 216 to a water-resistant layer 226, and coating an adhesive layer
214 onto the outer face 226b of the water-resistant layer 226. The water insoluble,
transparent film layer can even be used in place of the release liner, in some embodiments.
As in the embodiment depicted in FIG. 15, when the adhesive construction 212' is
dry, it is non-tacky. However, when exposed to even a small amount of moisture,
such as the water in a water-based ink, the polymer layer 214 becomes tacky (pressure-sensitive).
Thus, it can be printed on and activated in the same manner as described above and
shown in FIG. 15. In many embodiments, however, it is advantageous to print the
image in reverse (as shown in FIG. 16(c)), for reasons that will now be described.
After the image is printed onto the construction, the release liner
may be removed and the remaining two-layer sandwich can be adhered to an object.
In those embodiments where the water-resistant layer 226 is transparent, the importance
of reverse printing becomes apparent. As shown in FIG. 16(e), a printed image construction
228 is adhesively attached to a bottle 240, with the activated regions 224 of the
polymer layer in direct contact with the bottle, and the water-resistant layer 226
outwardly disposed therefrom. The image 225' is visible through, and protected by,
the transparent water-resistant layer 226. Had the image not been reverse printed,
it would appear to be "backwards" once the printed image construction 228 was attached
to the bottle, at least from the perspective of viewing it directly, rather than
through the bottle. Reverse image printing corrects this problem. Software for reversing
the image of both text and pictures is commercially available from Adobe, under
the mark Photo Deluxe. Image reversing share ware, such as "L-View," can be downloaded
from the internet.
The present invention has been described and illustrated in several
examples and embodiments, but is not limited thereto. A person having ordinary skill
in the art to which this invention pertains will appreciate that variation and modification
of the compositions, materials, dimensions and other elements recited herein can
be practiced without departing from the invention. For example, the ink receptivity
of the adhesive can be enhanced by coating a thin (0.1 to 0.3 µm) layer of polyvinyl
alcohol, poly-hydroxyethyl methacrylate (p-HEMA), or similar hydrophilic polymer
on the outer face 214b of the adhesive layer. (If p-HEMA is employed, it should
be applied as a dilute ― less than 5% ― solution, to avoid incompatibility
with the emulsion polymers.) Such a coating, when dry, also provides a protective
layer for the construction, particularly if the construction is self-wound.
A PVOH-coated, self-wound construction has been prepared, using biaxially
oriented polypropylene (BOPP) as both a transparent, water insoluble film layer
and a release liner, and the acrylic polymer corresponding to 1E, above. More particularly,
a 50 µm thick BOPP film, having a high energy side (38 x 10-5 N/cm) (38
dyne/cm surface tension) and a low energy side 32 x 10-5 N/cm) (32 dyne/cm
surface tension) was coated with the adhesive, at a coat weight of 25 grams per
square meter (g/m2) or, approximately 25 µm thick.
Two samples (I and II) were prepared by coating the low surface energy
side of the BOPP film with acrylic polymer. The high energy surface energy side
(the "back" side) was corona treated and coated with a thin (<0.1 µm thick) layer
of polyvinyl octadecyl carbamate (PVODC), a non-silicone release material. Specifically,
polyvinyl octadecyl carbamate, (PVODC), a non-silicone release material. Alternatively,
other release materials can be used. After the acrylic polymer was dried, Sample
I was coated with a thin layer ofPVOH, having a solids content of 1%, at a coat
weight of less than 0.24 g/m2. Sample II was coated with a thin layer of PVOH having
a solids content of 3%, at a coat weight of less than 0.12 g/m2.
Two other samples (III and IV) were prepared by coating the acrylic
polymer on the high surface energy side of the BOPP film. No release coating was
needed on the back side of the BOPP film, due to its low surface energy. After the
polymer was dried, Sample III was coated with 3% solids PVOH (<0.24 g/m2
coat weight), and Sample IV was coated with 1.5% solids PVOH (<0.12 g/m2
All four samples were fed through an ink jet printer and imaged directly
on the PVOH surface. Due to ink absorption through the PVOH and water-activatable
polymer layers, the polymer became tacky, and the image could be transferred to
a substrate as a "label-less" label, separated from the non-imaged part. The transparent,
water insoluble BOPP film protects the image while allowing it to be viewed when
adhered to a substrate.
It will be appreciated that this aspect of the invention is not limited
to constructions made with biaxially oriented polypropylene, but has a broader scope
that encompasses polymeric films in general, preferably transparent, water insoluble
films, including other polyolefins, polyesters, polystyrenes, and the like. All
such films have a front side and a back side. The relative surface energy of the
two sides may be equal or unequal, i.e., a given film may have a low energy side
and a high energy side. Similarly, other release coatings may be used in place of
polyvinyl octadecyl carbamate. Such coatings are known in the art, and include silicones
and other materials.
In some embodiments, it is advantages to score or die cut the release
liner and/or the water insoluble layer, in which case removal (delamination) of
the release liner from the adhesive becomes unnecessary.
Various further modifications and changes may be employed without
departing from the spirit and scope of the invention. Thus, as described hereinabove,
instead of using hydrophilic or repulpable adhesives, hydrophobic pressure sensitive
adhesives, or heat activated, or water activated adhesives, may be employed as the
imaging layer, with appropriate ink solvents so that the ink will penetrate this
imaging adhesive layer.
Also, instead of Mylar, other transparent plastic or opaque layers
may be employed as the support layer. For the outer detackifying layer, a very fine
metallic or cloth mesh with an open weave may be employed; and other substances
having comparable properties may be substituted for those mentioned hereinabove.
It is also noted that the ink jet absorbing layer may be detackified relative to
the ink jet printer by applying strips of paper with a silicone coating facing the
adhesive, and with the longitudinally extending strips of paper matched to the spacing
of the drive wheels of the ink jet printer; and the adhesive layer may be fully
activated following application of an ink jet image to areas of the adhesive layer
not covered by the strips, by peeling off the strips.
Furthermore, the present invention is not limited to use with ink-jet
printers, but may be utilized with similar printers and inks. Other methods of infusing
an ink-absorbent adhesive layer with a liquid ink to define an image, with the liquid
ink passing through a non-tack layer on its way to the adhesive layer, may be employed.
For example, a user could draw an image directly onto the image transfer assembly
using a felt-tip or other pen filled with a water-based ink of the type used in
ink jet printers. Consequently, the term "ink jet printer" is not strictly limited
to ink jet printers, but encompasses other methods of printing that utilize ink
jet printer-type ink.
A further application of the embodiment of Figs. 7-14 is as a replacement
for double-sided adhesive tape. For example, suppose someone wants to adhere a star-shaped
object onto a window. A typical way to stick the star-shaped object onto the window
is with strips of double-sided tape. However, this approach can be troublesome because
the tape comes in strips rather than in a star shape. The user could cut the strips
with scissors to form a star shape, or could carefully place several strips of different
lengths adjacent to one another to approximate a star shape, but either of these
approaches is time consuming and often frustrating.
To prevent such frustration, the user may instead print a star shape
onto one of the embodiments illustrated in Figs. 7-14. The user can transfer the
star shape onto the window as in Fig. 11. While the ink that defines the star remains
wet, the exterior surface of the star will be sticky. The user can then use the
star as she would use double sided tape, and adhere the star-shaped object directly
onto the star image.
As an alternative to the embodiments in which the adhesive is scored
or die cut, tiny glass beads maybe added to the adhesive layer. The adhesive typically
has very high cohesion, and the glass beads serve to break up the cohesion into
small zones by creating voids where there is no adhesive. Consequently, when the
user applies the freshly printed adhesive to a substrate, only the printed areas
of the adhesive will adhere to the substrate. As the user pulls the backing sheet
away from the substrate, the glass beads allow the printed adhesive to break cleanly
away from the unprinted adhesive, leaving only the printed adhesive on the substrate.
The glass beads will typically be within the range of 100 µm to 0.0127 mm (S mil)
in diameter, and perhaps even smaller. Other types of small particles, such as starch,
salts and/or other particles, maybe employed rather than glass particles.
It should also be understood that the figures are not production drawings,
but are intended to illustrate concepts, and the relative dimensions in the figures
do not necessarily correspond to the actual relative dimensions. Additionally, words
such as "upper," "lower," "inner," and "outer" are used for the purpose of illustrating
the relative position of one component with respect to another. However, in use,
the assembly is moved about, and what is illustrated as "upper" in the figures may
actually have a different orientation at a particular moment in time. Consequently,
relative terms are to be understood in a relative sense rather than in an absolute
Verfahren zur kalten Bildübertragung, das bei der Bildübertragung keine zusätzliche
Wärme nutzt und folgendes umfasst:
Bilden eines Bildübertragungsblatts mit den folgenden Schichten:
(a) einem Deckblatt; und
(b) einer Klebeschicht;
Aufbringen eines Bilds auf das Bildübertragungsblatt von einem Tintenstrahldrucker;
Aufbringen des Bildblatts auf ein Trägermaterial bei Umgebungstemperatur, wobei
mindestens ein Teil des Klebers direkt am Trägermaterial haftet; und
Entfernen des Deckblatts.
Verfahren nach Anspruch 1, wobei das Deckblatt eine Trennmittelbeschichtung
Verfahren nach einem der Ansprüche 1 bis 2, wobei das Deckblatt aus Kunststoff
Verfahren nach einem der Ansprüche 1 bis 2, wobei das Bildübertragungsblatt
weiter folgendes umfasst:
(a) eine für Tintenstrahl-Druckfarbe durchlässige entklebende Schicht.
Verfahren nach Anspruch 4, wobei die entklebende Schicht wasserlöslich ist.
Verfahren nach einem der Ansprüche 1 bis 5, wobei eine zusätzliche, nicht klebrige
Schicht zwischen dem Deckblatt mit einer Trennschicht und dem Kleber bereitgestellt
Verfahren nach einem der Ansprüche 1 bis 6, wobei die das Bild tragenden Anteile
des Klebers nach dem Entfernen des Deckblatts am Trägermaterial haften bleiben,
die Anteile des Klebers, die das Bild nicht tragen, jedoch am Deckblatt haften bleiben.
Verfahren nach Anspruch 1, wobei die Klebeschicht hydrophil ist.
Verfahren nach Anspruch 1, wobei die Klebeschicht hydrophob ist.
Verfahren nach einem der vorangehenden Ansprüche, wobei es sich bei der Klebeschicht
um einen selbsthaftenden Kleber handelt.
Verfahren nach einem der vorangehenden Ansprüche, wobei die Klebeschicht entklebt
wird, indem eine für Tintenstrahl-Druckfarbe poröse Außenschicht auf der Klebeschicht
positioniert wird, wobei die Außenschicht mindestens 30 Prozent der Druckfarbe
von Tintenstrahldruckern durch die poröse Schicht hindurch in den Kleber gelangen
lässt und der entklebte Kleber durch Entfernen der porösen Schicht aktiviert wird.
Verfahren nach Anspruch 11, wobei die poröse Außenschicht wasserdurchlässig
Verfahren nach Anspruch 11, wobei sich zwischen der porösen Außenschicht
und der Klebeschicht ein Trennblatt befindet.
Verfahren nach einem der vorangehenden Ansprüche, wobei die Klebeschicht durch
Wärme und/oder Druck aktiviert wird.
Verfahren nach einem der vorangehenden Ansprüche, wobei die Klebeschicht entklebt
wird, indem eine für Tintenstrahl-Druckfarbe poröse Schicht über der Klebeschicht
positioniert wird, wobei die poröse Schicht aus fein getrennten, gleichmäßig
auf der Klebeschicht verstreuten Partikeln gebildet wird.
Verfahren nach Anspruch 15, wobei die Partikel den selben Brechungsindex haben,
wie die Klebeschicht.
Verfahren nach Anspruch 16, wobei die Partikel Stärkepartikel und/oder Polyvinylalkoholpartikel
Verfahren nach einem der vorangehenden Ansprüche, wobei die flexible Basisschicht
Verfahren nach einem der vorangehenden Ansprüche, wobei sich zwischen der flexiblen
Basisschicht und der Klebeschicht eine Trennschicht befindet.
Verfahren nach einem der vorangehenden Ansprüche, wobei die Klebeschicht diskrete
Zonen umfasst, die entlang Grenzen voneinander getrennt sind.
Verfahren nach Anspruch 20, wobei es sich bei den diskreten Kleberzonen um gedruckte
Kleberpunkte und bei den Grenzen um Ränder dieser Punkte handelt.
Verfahren nach Anspruch 20 oder 21, wobei die Grenzen in einem feinen Gittermuster
angeordnete Schwächelinien sind, so dass die Zonen in einem feinen regelmäßigen
Muster angeordnet sind.
Verfahren nach einem der Ansprüche 20 bis 22, wobei die Zonen nicht mehr als
ungefähr 25,4 µm (1 mil) breit sind.
Verfahren nach Anspruch 1, wobei es sich beim Kleber um einen wasseraktivierten
Kleber handelt, der folgendes umfasst:
ein aus einem Gemisch von Monomeren gebildetes Polymer, das, basierend auf dem
Gesamtgewicht der Monomere, folgendes umfasst:
(a) zu zwischen etwa 40 und etwa 70 Gewichtsprozent ein oder mehrere Alkylacrylate,
wobei die Alkylgruppe derselben zwischen etwa 4 und etwa 8 Kohlenstoffatome hat;
(b) zu zwischen etwa 20 und etwa 20 Gewichtsprozent Methylacrylat;
(c) zu zwischen etwa 2 und etwa 15 Gewichtsprozent Vinylacetat;
(d) zu zwischen etwa 10 und etwa 25 Gewichtsprozent Methacrylsäure, Acrylsäure
oder eine Mischung aus Methacrylsäure und Acrylsäure;
(e) eine positive Menge von bis zu 30 Gewichtsprozent, basierend auf dem Gesamtgewicht
der Monomere, Methylmethacrylat;
und wobei das Polymer bei Raumtemperatur, wenn trocken, nicht klebrig ist, aber
wenn feucht, klebrig ist.
Verfahren nach Anspruch 24, wobei die Monomermischung weiter eine positive Menge
von bis zu etwa 5 Gewichtsprozent, basierend auf dem Gesamtgewicht der Monomere,
eines Hydroxyalkylmethacrylats umfasst.
Verfahren nach Anspruch 25, wobei das Hydroxyalkylmethacrylat Hydroxyethylmethacrylat
Verfahren nach Anspruch 26, wobei das Alkylacrylat aus der aus Butylacrylat,
Ethylhexylacrylat, Isooctylacrylat und Gemischen derselben bestehenden Gruppe gewählt
Verfahren nach Anspruch 1 oder 2, wobei:
es sich beim Deckblatt um eine Polymerfolie mit einer Vorderseite und einer
die Vorderseite der Polymerfolie mit einer Schicht eines mit Wasser aktivierbaren
Acrylmaterials beschichtet ist, wobei das Acrylmaterial, wenn trocken, nicht klebrig
ist, aber wenn feucht, klebrig ist; und
das Acrylmaterial mit einer Schicht aus Polyvinylalkohol oder Polyhydroxyethylmethacrylat
Verfahren nach Anspruch 28, wobei die Polymerfolie biaxial orientiertes Polypropylen
Verfahren nach einem der Ansprüche 28 bis 29, das weiter das Bereitstellen einer
Trennmittelbeschichtung auf der Rückseite der Polymerfolie umfasst.
Verfahren nach einem der Ansprüche 28 bis 30, wobei die Vorderseite und die
Rückseite der Polymerfolie ungleiche Oberflächenenergien aufweisen.
Verfahren nach Anspruch 1 oder 2, wobei:
es sich beim Deckblatt um eine Polymerfolie mit einer Vorderseite mit hoher
Oberflächenenergie und einer Rückseite mit niedriger Oberflächenenergie handelt
und die Vorderseite der Polymerfolie mit einer mit Wasser aktivierbaren Schicht
aus Acrylmaterial beschichtet ist, wobei das Acrylmaterial, wenn trocken, nicht
klebrig ist, aber wenn feucht, klebrig ist;
und das Acrylmaterial eine Zusammensetzung gemäß einem der Ansprüche 24
bis 27 aufweist.
Verfahren nach Anspruch 1, wobei das Bildübertragungsblatt weiter folgendes
umfasst: eine erste entklebende Schicht, die eine Druckoberfläche des Blatts bildet,
eine flüssige Druckfarbe absorbierende Klebeschicht, die sich unter der ersten entklebenden
Schicht befindet, eine zweite entklebende Schicht, die sich unter der flüssige Druckfarbe
absorbierenden Klebeschicht befindet und ein flexibles, nicht poröses Deckblatt,
das sich unter der zweiten entklebenden Schicht befindet;
wobei die erste entklebende Schicht zulässt, dass mindestens ein Teil der flüssigen
Druckfarbe, die auf die erste Schicht gedruckt wird, durch sie hindurch zur Klebeschicht
Verfahren nach Anspruch 33, das folgendes umfasst:
(a) Drucken eines Bilds mit flüssiger Druckfarbe auf der Druckoberfläche und
mindestens teilweise in die Klebeschicht, wodurch die Druckoberfläche, dort wo das
Bild gedruckt wurde, klebrig gemacht wird, wobei das Bild einen klebrig gemachten
bedruckten Teil des Bildübertragungsblatts bildet;
(b) Kleben, nach dem Drucken des Bilds, des klebrig gemachten bedruckten Teils
des Bildübertragungsblatts auf ein Trägermaterial, indem die Druckoberfläche auf
das Trägermaterial aufgebracht wird; und
(c) Abziehen, nach dem Kleben des bedruckten Teils des Bildübertragungsblatts
auf ein Trägermaterial, des Deckblatts vom Trägermaterial, wodurch der bedruckte
Teil des Bildübertragungsblatts am Trägermaterial kleben gelassen wird.
Verfahren nach Anspruch 34, wobei nach dem Schritt des Abziehens mindestens
ein Teil der zweiten entklebenden Schicht eine Oberfläche des bedruckten Teils des
Verfahren nach einem der Ansprüche 33 bis 35, wobei der Schritt des Druckens
bedruckte und unbedruckte Teile der Klebeschicht bildet, wobei die bedruckten Teile
nach dem Schritt des Abziehens am Trägermaterial haften und die unbedruckten Teile
am Deckblatt haften und beim Schritt des Abziehens mit ihm abgezogen werden.
Verfahren nach einem der Ansprüche 33 bis 36, wobei der Schritt des Aufbringens
des haftenden Bildblatts ausgeführt wird, bevor das gedruckte Bild getrocknet ist.
A cold image transfer method using no supplemental heat in the course of image
forming an image transfer sheet having the following layers:
(a) a liner sheet; and
(b) an adhesive layer;
applying an image to said image transfer sheet from an ink jet printer;
applying said image sheet to a substrate at ambient temperature with at least
a portion of said adhesive bonding directly to said substrate; and
removing said liner.
A method as defined in Claim 1 wherein said liner is release coated.
A method as defined in any of claims 1 to 2 wherein said liner is plastic.
A method as defined in any of claims 1 to 2 wherein said image transfer sheet
(a) an ink jet ink transmissive detackifying layer.
A method as defined in Claim 4 wherein said detackifying layer is water-soluble.
A method as defined in any of claims 1 to 5 wherein an additional non-tacky
layer is provided between said release-coated backing and said adhesive.
A method as defined in any of claims 1 to 6, wherein after removing said liner
sheet the portions of said adhesive that bear the image remain attached to the substrate
but the portions of the adhesive that do not bear the image remain attached to the
A method according to claim1 wherein said adhesive layer is hydrophilic.
A method according to claim1 wherein the adhesive layer is hydrophobic.
A method according to any ofthe previous claims wherein said adhesive layer
is a pressure sensitive adhesive.
A method according to any of the previous claims wherein said adhesive layer
is detackified by locating an ink jet printing ink porous outer layer on the adhesive
layer, said outer layer permitting at least 30 percent of the ink from inkj et printers
to pass through the porous layer into said adhesive and the detackified adhesive
is activated by removing said porous layer.
A method according to claim 11 wherein said porous outer layer is water permeable.
A method according to claim 11 wherein there is a release liner between said
porous outer layer and said adhesive layer.
A method according to any of the previous claims wherein said adhesive layer
is activated by heat and/or pressure.
A method according to any of the previous claims wherein said adhesive layer
is detackified by locating an ink jet printing ink porous layer over the adhesive
layer, said porous layer being formed of fmely divided particles uniformly dispersed
on said adhesive layer.
A method according to claim 15 wherein said particles have the same refractive
index as the adhesive layer.
A method according to claim 16 wherein said particles comprise starch particles
and/or polyvinyl alcohol particles.
A method according to any of the previous claims wherein said flexible base
layer is transparent.
A method according to any of the previous claims wherein there is located between
said flexible base layer and said adhesive layer a release layer.
A method according to any of the previous claims wherein said adhesive layer
comprises discrete zones separated from one another along boundaries.
A method as defined in claim 20, wherein said discrete zones ofadhesive are
printed dots of adhesive and said boundaries are edges of said dots.
A method as defined in either of claims 20 or 21, wherein said boundaries are
lines of weakness arranged in a fine grid pattern, such that said zones are arranged
in a fine array.
A method as defined in any of claims 20 to 22, wherein said zones are no more
than approximately 25,4 µm (1 mil) wide.
A method as defined in claim 1, wherein said adhesive is a water-activated adhesive
a polymer formed from a mixture ofmonomers comprising, based on the total weight
(a) from about 40 to about 70 percent by weight of one or more alkyl acrylates,
the alkyl group of which has from about 4 to about 8 carbon atoms;
(b) from about 10 to about 20 percent by weight of methyl acrylate;
(c) from about 2 to about 15 percent by weight of vinyl acetate;
(d) from about 10 to about 25 percent by weight of methacrylic acid, acrylic
acid, or a mixture of methacrylic and acrylic acid;
(e) a positive amount up to about 30 percent by weight, based on the total weight
of monomers, of methyl methacrylate;
and said polymer is non-tacky at room temperature when dry, but tacky when wet.
A method as defined in claim 24, wherein the monomer mixture further comprises
a positive amount up to about 5 percent by weight, based on the total weight of
monomers, of a hydroxyalkylmethacrylate.
A method as defined in claim 25, wherein the hydroxyalkyl methacrylate comprises
A method as defined in claim 26, wherein the alkylacrylate is selected from
the group consisting of butyl acrylate, ethylhexylacrylate, isooctyl acrylate, and
A method as defined in claim 1 or 2 wherein:
said liner is a polymeric film having a front side and a back side;
a layer of a water-activatable, acrylic material is coated on the frontside
of the polymeric film, said acrylic material being non-tacky when dry, but tacky
when wet; and
there is a layer of polyvinyl alcohol or polyhydroxyethyl methacrylate coated
on the acrylic material.
A method as defined in claim 28, wherein the polymeric film comprises biaxially
A method as defined in any of claims 28 to 29, further comprising providing
a release coating on the back side of the polymeric film.
A method as defined in any of claims 28 to 30, wherein the polymeric film's
front side and back side have unequal surface energies.
A method as defined in claim 1 or 2, wherein:
said liner is a polymeric film having ahigh surface energy front side and a
low surface energy back side, and a layer of water-activatable, acrylic material,
is coated on the front side ofthepolymeric film, said acrylic material being non-tacky
when dry, but tacky when wet;
and the acrylic material comprises a composition as recited in any one of claims
24 to 27.
A method as defined in claim 1, wherein:
said image transfer sheet further comprises a first detackifying layer forming
a printing surface of said sheet, a liquid ink-absorbing adhesive layer underlying
said first detackifying layer, a second detackifying layer underlying said liquid
ink-absorbing adhesive layer, and a flexible, non-porous backing sheet underlying
said second detackifying layer, said first detackifying layerpermitting at least
aportion of liquid ink that is printed on said first layer to pass through to said
A method as defined in claim 33 comprising:
(a) printing an image with liquid ink on the printing surface and at least partially
into said adhesive layer, thereby tackifying the printing surface where the image
has been printed, said image forming a tackified printed portion of said image transfer
(b) after printing the image, adhering the tackified printed portion of said
image transfer sheet to a substrate by applying the printing surface to the substrate;
(c) after adhering the printed portion of said image transfer sheet to a substrate,
peeling said backing sheet from the substrate, thereby leaving said printed portion
of said image transfer sheet adhered to said substrate.
A method as defined in claim 34, wherein after said peeling step at least aportion
of said second detackifying layer covers a surface of said printed portion of said
image transfer sheet.
A method as defined in any of claims 33 to 35, wherein said printing step forms
printed and unprinted portions of said adhesive layer, said printed portions adhering
to said substrate after said peeling step and said unprinted portions adhering to
and peeling with said backing sheet in said peeling step.
A method according to anyofclaims 33 to 36, wherein the step of applying said
adhering image sheet is done before the printed image has dried.
Méthode de transfert d'image à froid n'utilisant aucune chaleur supplémentaire
au cours du transfert d'image, comprenant :
la formation d'une feuille de transfert d'image ayant les couches suivantes
(a) une feuille de doublure ; et
(b) une couche adhésive ;
l'application d'une image sur ladite feuille de transfert au moyen d'une imprimante
à jet d'encre ;
l'application de ladite feuille d'image sur un substrat à la température ambiante
avec au moins une portion dudit adhésif collant directement audit substrat ; et
l'enlèvement de ladite doublure.
Méthode telle que définie dans la revendication 1 dans laquelle ladite doublure
est enduite d'un agent anti-adhérent.
Méthode telle que définie dans la revendication 1 à 2 dans laquelle ladite doublure
est en plastique.
Méthode telle que définie dans l'une quelconque des revendications 1 à 2 dans
laquelle ladite feuille de transfert d'image comprend également :
(a) une couche rendant sec au toucher transmissive d'encre d'impression jet
Méthode telle que définie dans la revendication 4 dans laquelle ladite couche
rendant sec au toucher est soluble à l'eau.
Méthode telle que définie dans l'une quelconque des revendications 1 à 5 dans
laquelle une couche non collante supplémentaire est prévue entre ledit support enduit
d'agent anti-adhérent et ledit adhésif.
Méthode telle que définie dans l'une quelconque des revendications 1 à 6 dans
laquelle, après avoir enlevé ladite feuille de doublure, les portions dudit adhésif
qui portent l'image restent attachées au substrat mais les portions de l'adhésif
qui ne portent pas l'image restent attachées à la feuille de doublure.
Méthode selon la revendication 1 dans laquelle ladite couche adhésive est hydrophile.
Méthode selon la revendication 1 dans laquelle ladite couche adhésive est hydrophobe.
Méthode selon l'une quelconque des revendications précédentes, dans laquelle
ladite couche adhésive est un adhésif par pression.
Méthode selon l'une quelconque des revendications précédentes dans laquelle
ladite couche adhésive est rendue sèche au toucher en plaçant une couche extérieure
poreuse à l'encre d'impression jet d'encre sur la couche adhésive, ladite couche
extérieure permettant à au moins 30 % de l'encre venant de l'imprimante jet d'encre
de traverser la couche poreuse pour pénétrer dans ledit adhésif et l'adhésif rendu
sec au toucher est activé en enlevant ladite couche poreuse.
Méthode selon la revendication 11 dans laquelle ladite couche extérieure poreuse
est perméable à l'eau.
Méthode selon la revendication 11 dans laquelle il y a une doublure anti-adhérente
entre ladite couche extérieure poreuse et ladite couche adhésive.
Méthode selon l'une quelconque des revendications précédentes dans laquelle
ladite couche adhésive est activée par chaleur et/ou pression.
Méthode selon l'une quelconque des revendications précédentes dans laquelle
ladite couche adhésive est rendue sèche au toucher en plaçant une couche poreuse
à l'encre d'impression jet d'encre au-dessus de la couche adhésive, ladite couche
poreuse étant formée de particules finement divisées dispersées uniformément sur
ladite couche adhésive.
Méthode selon la revendication 15 dans laquelle lesdites particules ont le même
indice de réfraction que la couche adhésive.
Méthode selon la revendication 16 dans laquelle lesdites particules comprennent
des particules d'amidon et/ou des particules de poly(alcool de vinyle).
Méthode selon l'une quelconque des revendications précédentes dans laquelle
ladite couche de base flexible est transparente.
Méthode selon l'une quelconque des revendications précédentes dans laquelle
une couche anti-adhérente est placée entre ladite couche de base flexible et ladite
Méthode selon l'une quelconque des revendications précédentes dans laquelle
ladite couche adhésive comprend des zones distinctes séparées les unes des autres
le long de limites.
Méthode telle que définie dans la revendication 20, dans laquelle lesdites zones
distinctes d'adhésif sont des points imprimés d'adhésif et lesdites limites sont
les bords desdits points.
Méthode telle que définie dans l'une ou l'autre des revendications 20 ou 21,
dans laquelle lesdites limites sont des lignes de faiblesse disposées suivant un
motif de grille fine, tel que lesdites zones sont disposées dans un fin réseau.
Méthode telle que définie dans l'une quelconque des revendications 20 à 22,
dans laquelle lesdites zones n'ont pas plus de 25,4 µm de large.
Méthode telle que définie dans la revendication 1, dans laquelle ledit adhésif
est un adhésif réactivé à l'eau et comprend :
un polymère formé à partir d'un mélange de monomères comprenant, en se basant
sur le poids total des monomères,
(a) un pourcentage d'environ 40 % à environ 70 % en poids d'un ou plusieurs
acrylates d'alkyle, dont le groupe d'alkyles a entre environ 4 et environ 8 atomes
(b) un pourcentage d'environ 10 % à environ 20 % en poids d'acrylate de méthyle
(c) un pourcentage d'environ 2 % à environ 15 % en poids d'acétate de vinyle
(d) un pourcentage d'environ 10 % à environ 25 % en poids d'acide méthacrylique,
d'acide acrylique ou d'un mélange d'acide méthacrylique et d'acide acrylique ;
(e) une quantité positive d'environ 30 % en poids, basée sur le poids total
des monomères, de méthacrylate de méthyle ;
et ledit polymère est non collant à la température ambiante lorsqu'il est sec,
mais collant lorsqu'il est humide.
Méthode telle que définie dans la revendication 24, dans laquelle le mélange
de monomères comprend également une quantité positive d'environ 5 % maximum en poids,
basé sur le poids total des monomères, d'un méthacrylate d'hydroxyalkyle.
Méthode telle que définie dans la revendication 25, dans laquelle le méthacrylate
d'hydroxyalkyle comprend du méthacrylate d'hydroxyéthyle.
Méthode telle que définie dans la revendication 26, dans laquelle l'acrylate
d'alkyle est sélectionné dans le groupe constitué par l'acrylate de butyle, l'acrylate
d'éthylhexyle, l'acrylate isooctylique, et les mélanges de ceux-ci.
Méthode telle que définie dans la revendication 1 ou 2 dans laquelle :
ladite doublure est une pellicule polymère ayant un côté avant et un côté arrière
une couche de la matière acrylique ré-activable à l'eau est enduite sur le côté
avant de la pellicule polymère, ladite matière acrylique étant non collante lorsqu'elle
est sèche, mais collante lorsqu'elle est humide ; et
il y a une couche de poly(alcool de vinyle) ou de méthacrylate polyhydroxyéthyle
enduite sur la matière acrylique.
Méthode telle que définie dans la revendication 28, dans laquelle la couche
polymère comprend du polypropylène orienté de manière bi-axiale.
Méthode telle que définie dans l'une quelconque des revendications 28 à 29,
comprenant également la prévision d'une couche anti-adhérente sur le côté arrière
de la pellicule polymère.
Méthode telle que définie dans l'une quelconque des revendications 28 à 30,
dans laquelle le côté avant et le côté arrière de la pellicule polymère ont des
tensions superficielles inégales.
Méthode telle que définie dans la revendication 1 ou 2, dans laquelle :
ladite doublure est une pellicule polymère ayant un côté avant à tension superficielle
élevée et un côté arrière à tension superficielle faible, et une couche de matière
acrylique ré-activable à l'eau est enduite sur le côté avant de la pellicule polymère,
ladite matière acrylique étant non collante lorsqu'elle est sèche, mais collante
lorsqu'elle est humide ;
et la matière acrylique comprend une composition telle que spécifiée dans l'une
quelconque des revendications 24 à 27.
Méthode telle que définie dans la revendication 1, dans laquelle :
ladite feuille de transfert d'image comprend également une première couche rendant
sec au toucher formant une surface d'impression de ladite feuille, une couche adhésive
absorbant l'encre liquide, sous-jacente à ladite première couche rendant sec au
toucher, une deuxième couche rendant sec au toucher sous-jacente à ladite couche
adhésive absorbant l'encre liquide, et une feuille de support flexible non poreuse
sous-jacente à ladite deuxième couche rendant sec au toucher, ladite première couche
rendant sec au toucher permettant à au moins une portion de l'encre liquide qui
est imprimée sur ladite première couche de passer à travers ladite couche adhésive.
Méthode telle que définie dans la revendication 33, comprenant :
(a) l'impression d'une image avec de l'encre liquide sur la surface d'impression
et au moins partiellement dans ladite couche adhésive, rendant ainsi collante la
surface d'impression où l'image a été imprimée, ladite image formant une portion
imprimée rendue collante de ladite feuille de transfert d'image ;
(b) après avoir imprimé l'image, l'adhésion de la portion imprimée rendue collante
de ladite feuille de transfert d'image sur un substrat en appliquant la surface
d'impression sur le substrat ; et
(c) après l'adhésion de la portion imprimée de ladite feuille de transfert d'image,
le dépouillement de ladite couche de support du substrat, laissant ainsi la portion
imprimée de la feuille de transfert d'image adhérant audit substrat.
Méthode telle que définie dans la revendication 34, dans laquelle, après ladite
opération de dépouillement, au moins une portion de ladite deuxième couche rendant
sec au toucher couvre une surface de ladite portion imprimée de ladite feuille de
Méthode telle que définie dans l'une quelconque des revendications 33 à 35,
dans laquelle ladite opération d'impression forme des portions imprimées et non
imprimées de ladite couche adhésive, lesdites portions imprimées adhérant audit
substrat après ladite opération de dépouillement et lesdites portions non imprimées
adhérant à ladite feuille de support et se dépouillant avec elle lors de ladite
opération de dépouillement.
Méthode selon l'une quelconque des revendications 33 à 36, dans laquelle l'opération
de l'application de ladite feuille de transfert d'image est effectuée avant que
l'image imprimée n'ait séché.