U.S. patent application number 11/271652 was filed with the patent office on 2006-03-23 for laminated imaged recording media.
This patent application is currently assigned to NuCoat, Inc.. Invention is credited to Nabil Nasser.
Application Number | 20060060101 11/271652 |
Document ID | / |
Family ID | 36101909 |
Filed Date | 2006-03-23 |
United States Patent
Application |
20060060101 |
Kind Code |
A1 |
Nasser; Nabil |
March 23, 2006 |
Laminated imaged recording media
Abstract
The present invention provides a method for manufacturing an
identification document that can contain both common information
and unique information describing the specific document holder. The
information is in the form of indicia applied by digital imaging
means. The document itself is in the form of a laminated article
having the information affixed to one or more internal layers.
Attempt to gain access to these internally imaged layers causes the
image to be sufficiently disrupted as to prevent modifying such
images.
Inventors: |
Nasser; Nabil; (Woodbury,
MN) |
Correspondence
Address: |
SCHWEGMAN, LUNDBERG, WOESSNER & KLUTH
1600 TCF TOWER
121 SOUTH EIGHT STREET
MINNEAPOLIS
MN
55402
US
|
Assignee: |
NuCoat, Inc.
|
Family ID: |
36101909 |
Appl. No.: |
11/271652 |
Filed: |
November 10, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10264848 |
Oct 4, 2002 |
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11271652 |
Nov 10, 2005 |
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60326684 |
Oct 4, 2001 |
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Current U.S.
Class: |
101/483 |
Current CPC
Class: |
B41M 3/14 20130101; B41M
5/529 20130101; B32B 2255/10 20130101; G03G 7/0073 20130101; B32B
2307/412 20130101; B32B 25/08 20130101; G03G 7/0093 20130101; B32B
7/12 20130101; B32B 27/36 20130101; B32B 2307/4023 20130101; G03G
7/004 20130101; G03G 7/0066 20130101; B32B 2425/00 20130101; G03G
7/0053 20130101; B32B 27/08 20130101; B32B 2307/75 20130101; B32B
25/12 20130101; B41M 7/0027 20130101; B41M 2205/38 20130101; B32B
2250/24 20130101; B32B 27/20 20130101; G03G 7/008 20130101; G03G
7/006 20130101; G03G 7/0046 20130101; B41M 2205/40 20130101; B32B
2255/28 20130101; B32B 2255/26 20130101; B32B 2264/101
20130101 |
Class at
Publication: |
101/483 |
International
Class: |
B41F 33/00 20060101
B41F033/00 |
Claims
1. A process for generating a security identity card comprising the
steps of: a) providing a support comprising an upper major lateral
surface; b) applying a layer of a polyurethane to said upper major
lateral surface of said support; c) applying a layer of a
siloxane-modified polyoxyalkylene oxide to said polyurethane layer;
and d) imaging said siloxane-modified polyoxyalkylene oxide layer
in order to generate an intermediate imaged construction.
2. The process for generating a security identity card as described
in claim 1 wherein steps (b) and (c) are performed
simultaneously.
3. The process for generating a security identity card as described
in claim 2 wherein said imaging step comprises receiving an ink
image to predetermined areas of said siloxane-modified
polyoxyalkylene oxide layer.
4. The process for generating a security identity card as described
in claim 3 wherein said ink image is applied by an ink-jet
recorder, thermal transfer medium, or lithographic printing
means.
5. The process for generating a security identity card as described
in claim 1 wherein said imaging step comprises receiving a toner
image to predetermined areas of said siloxane-modified
polyoxyalkylene oxide layer.
6. The process for generating a security identity card as described
in claim 5 wherein said toner image is applied by
electrophotographic or laser printer.
7. The process for generating a security identity card as described
in claim 1 further comprising the steps of: e) providing a
composite comprising a transparent protective film overcoated with
a resin; f) placing said resinous coating from said composite in
intimate contact with said imaged siloxane-modified polyoxyalkylene
oxide layer from said intermediate construction; and g) subjecting
said composite and said intermediate construction to a heat
treatment in order to produce a laminated security identity card.
Description
RELATED APPLICATIONS
[0001] This application claims priority from U.S. Provisional
Patent Application Ser. No. 60/326,684, filed Oct. 4, 2001.
FIELD OF THE INVENTION
[0002] This invention relates to the process of laminating an
imaged substrate and, more particularly, to a laminated ink-jet
imaged article for identity preservation and falsification
prevention.
BACKGROUND OF THE INVENTION
[0003] With the advent of computer controlled digital imaging
techniques such as ink-jet or electrophotographic printing, it is
now possible to mass-produce individualized printed copies. This
has created many new markets for these imaging technologies. For
example, labeling, bar coding, targeted advertising, and even
individualized book publishing are now performed in this manner as
opposed to standard printing techniques. Although this has obvious
advantages for legitimate business, the same technology also allows
for its misuse by permitting unauthorized duplication of original
documents for the purpose of passing them off as original
documents. For example, these imaging techniques have been used to
generate false identity cards or counterfeit currency. To ensure
valid, authentic documentation, additional security devices must be
employed that will prevent accurate reproduction of original
documentation so falsified documents can easily be detected either
by eye or with low cost reading technologies.
[0004] Many types of identification cards and documents, such as
driving licenses, national or government identification cards, bank
cards, credit cards, controlled access cards and smart cards carry
information relating to the identity of the bearer. The most
important items of information are name, address, birth date,
signature and photographic image. Additionally, the cards or
documents may carry other variant data (i.e., data specific to a
particular card or document, like an employee number, for example)
and invariant data (i.e., data common to a large number of cards,
like the name of an employer). All of the cards described above
will hereinafter be generically referred to as "identification
documents."
[0005] Commercial systems for issuing identification documents are
of two main types, namely "on-the-spot" or "over-the-counter" (OTC)
issue, and "central" issue. As the name implies, the former are
issued immediately to a bearer who is present at a document-issuing
station, whereas with the latter type, a bearer reports to a
document station where data is collected, the data are forwarded to
a central location where the card is produced, and the card is
forwarded to the bearer, often by mail.
[0006] Centrally issued digital identification documents generally
comprise an opaque laser or ink-jet printed core material,
typically either paper or plastic, sandwiched between two layers of
clear plastic laminate, typically polyester, to protect the
aforementioned items of information from wear, exposure to the
elements and tampering. The materials used in such centrally issued
digital identification documents can offer the ultimate in
durability. In addition, centrally issued digital identification
documents generally offer a higher level of security than digital
OTC identification documents because they have the ability to
pre-print the laser or ink-jet printed core of the central issue
document with "micro-printing," ultra-violet security features,
security indicia, and other features currently unique to centrally
issued identification documents.
[0007] The use of ink-jet technology to produce essentially
permanent customized images for identity cards would seem to have
potential, but several problems have remained. In particular,
ink-jet imaged products have not provided highly water resistant or
waterproof characteristics. Furthermore, ink-jet inks are prone to
fade with time. Also, lamination of such products typically has
caused image alteration due to melting of the image-receiving
layer. Another limitation of the present protection technology is
that delamination can be effected without destroying the image and
therefore permitting modification or falsification of
information.
[0008] Furthermore, it has been a general long-standing problem in
the art to provide a recording sheet for ink-jet printing which is
receptive to inks, allows the ink to dry quickly without running or
smearing, provides sharp image quality and has very good water and
humidity resistance which deters curling. Many attempts have been
made to produce recording sheets for ink-jet printing which
simultaneously have all of these properties.
[0009] U.S. Pat. No. 4,371,582, issued to Sugiyama et al. on Feb.
1, 1983 for INK-JET RECORDING SHEET describes an ink-jet recording
sheet containing a basic latex polymer. U.S. Pat. No. 3,158,494,
issued to Elkvar et al. on Nov. 24, 1964 for COATED POLYMERIC
THERMOPLASTIC SHEET MATERIAL describes a polyurethane ink receptive
surface. U.S. Pat. No. 5,693,410, issued to Malhotra et al. on Dec.
2, 1997 for INK-JET TRANSPARENCIES describes ink-jet recording
transparencies having two coatings, namely a heat dissipating, fire
resistant coating in contact with a substrate and a second ink
receiving coating layer on the first layer comprising a hydrophilic
binder, an ink spreading agent, a cationic component, a
light-fastness inducing agent, a filler and a biocide. JP Pat.
92/02,041 describes ink-jet recording media having good ink drying
properties comprising a substrate provided with at least one ink
receiving layer which contains a reaction product of polyalkylene
oxide with an isocyanate and a water insoluble cellulose compound.
While the above ink-jet media may be suitable for intended
purposes, there remains a need for a universal ink-jet media for a
dye based ink system as well as a pigment based ink system.
Further, there is a need for a universal ink-jet media useful for
obtaining photographic quality prints by both thermal and piezo
ink-jet printing technologies. Additionally, there remains a need
for coatings for ink-jet media which have good water resistance and
which can counter media curl due to humidity changes.
[0010] With regard to water resistance, significant effort has been
expended on improving either the ink systems or the recording
medium to achieve an image that will possess superior water
resistance. Due to the interaction of the ink with the
image-receiving layer it was not uncommon to create dedicated
ink/substrate systems. Typically, one of the major advantages of
the ink-jet imaging process is that the dyes employed are mainly
water-soluble. Therefore, the system requires little or no organic
solvent and is mainly water-based or aqueous media thereby creating
a system that is environmentally friendly. However, this presents a
significant design problem if, on the other hand, water resistance
is required for the final imaged article. Inks utilizing pigments
have been used to alleviate this problem since the pigments
themselves are not water soluble and therefore after imaging will
not run or bleed. However, the pigment particles generally, will
not be absorbed into the image receiver layer, but rather reside on
its surface and therefore can be easily removed by physical
abrasion.
[0011] In U.S. Pat. No. 6,225,381, issued to Sharma et al. on May
1, 2001 for PHOTOGRAPHIC QUALITY INK-JET PRINTABLE COATING ink-jet
printable-coated media that overcome the above-noted disadvantages
the invention provides coating compositions that, when applied to
suitable substrates such as transparent, translucent, or opaque
white plastic films, paper, or the like, can achieve photographic
quality prints by using any of a variety of ink-jet printers. The
coating composition is compatible with dye based and pigment based
ink systems, which can be printed both by thermal type ink-jet
printers and piezo type ink-jet printers.
[0012] In U.S. Pat. No. 5,494,960, issued to Rolando et al. on Feb.
27, 1996 for AQUEOUS POLYURETHANE DISPERSIONS AND ADHESIVES BASED
THEREON, aqueous polyurethane dispersions having anionic moieties
which can be used in adhesives for manufacturing laminate
structures with improved dispersion properties, which provide
improved shelf-life stability of the dispersion and greater
transparency and handling characteristics in application machinery
for adhesives formulated therefrom, when a tertiary amine is
present during an initial polyurethane prepolymer reaction between
an isocyanate and a polyol component having acid functional groups
are reported. The initial reaction is carried out prior to
formation of the dispersion in water.
[0013] Polyurethanes having anionic moieties have been reported in
U.S. Pat. No. 5,691,425, issued to Klein et al. on Nov. 25, 1997
for POLYURETHANE DISPERSIONS. Klein et al. disclose that their
inventive polyurethane dispersions are suitable for diverse uses,
for instance, in the preparation of coating systems, inter alia for
coating wood, as binders for water-dilutable adhesives or as resins
for printing inks.
[0014] Nakamura et al., in U.S. Pat. Nos. 5,470,818, issued on Nov.
28, 1995 for PRINTING SHEET COMPRISING A DYE RECEIVING LAYER MADE
OF AN ISOCYANATE GROUP-CONTAINING POLYMER and 5,470,817, issued on
Nov. 28, 1995 for PRINTING SHEET AND MANUFACTURING METHOD THEREFOR,
report a printing sheet adapted for use in thermal transfer
recording comprising a substrate (1) and a dye image-receiving
layer (2) formed on the substrate. The layer (2) comprises an
isocyanate group-containing polymer having at least one
polysiloxane moiety and at least one urethane bond site therein.
The isocyanate group-containing polymer is a reaction product
between polyfunctional polyisocyanate compound and alcohol-modified
silicone. A method for making such a sheet is also described.
However, Nakamura et al. are concerned with optimizing a thermal
ink receiving sheet that has low smearing by hand and acceptable
writability. No mention is made of the need or desire to laminate
this imaged material.
[0015] In U.S. Pat. Nos. 5,022,947, both issued to Hasegawa et al.
on Jun. 11, 1991 for METHOD FOR THE PREPARATION OF A
WATER-RESISTANT PRINTED MATERIAL, and 4,966,804, issued on Oct. 30,
1990 for PRINTED MATERIAL IMPARTED WITH IMPROVED WATER-PROOFNESS, a
means to prepare a highly water-resistant printed material by the
ink-jet printing method despite the water-solubility of the dye in
the aqueous ink used in the ink-jet printing method is reported.
The inventive method comprises overcoating the surface of the sheet
material, which has a water-absorptive surface layer with
receptivity of the aqueous ink and printed by the ink-jet printing
method, with a curable polyisocyanate compound and bringing the
overcoating layer under a condition capable of curing the
polyisocyanate compound. This patent makes no reference to
laminating the isocyanate layer to any other material. Rather the
intent is to harden or cure the isocyanate to improve
waterfastness.
[0016] In U.S. Pat. No. 4,578,285, issued to Michael S. Viola on
Mar. 25, 1986 for INK-JET PRINTING SUBSTRATE, a printing substrate
adapted to receive ink droplets to form an image generated by an
ink-jet printer which comprises a transparent support carrying a
layer comprising at least 70 weight percent polyurethane and 5 to
30 weight percent of a polymer selected from the group consisting
of polyvinylpyrrolidone, polyvinylpyrrolidone/vinyl acetate
copolymer, poly (ethyleneoxide), gelatin and polyacrylic acid is
reported. No mention is made of subsequent lamination.
[0017] It is a general practice in conventional xerography to form
electrostatic latent images on a xerographic surface by first
uniformly charging a charge retentive surface such as a
photoreceptor. The charged area is selectively dissipated in
accordance with a pattern of activating radiation corresponding to
original images. The selective dissipation of the charge leaves a
latent charge pattern on the imaging surface corresponding to the
areas not exposed by radiation.
[0018] This charge pattern is made visible by developing it with
toner by passing the photoreceptor past one or more developer
housings. In monochromatic imaging, the toner is generally
comprised of black thermoplastic powder particles that adhere to
the charge pattern by electrostatic attraction. The developed image
is then fixed to the imaging surface or is transferred to a
receiving substrate such as plain paper to which it is fixed by
suitable fusing techniques.
[0019] The quality of color xerographic images on paper has
approached the quality of color photographic prints. However, color
xerographic prints fall short because they do not have the uniform
gloss, dynamic range, or brilliance typical of photographic prints.
Furthermore, xerographic prints do not have the feel of
photographic prints because the paper used is usually too
lightweight and limp.
[0020] Also the surface of color toner images is typically
irregular, therefore providing a rather rough or lumpy appearance.
The behavior of incident white light vis-a-vis such color images is
believed to be as follows: some of the white light incident on the
substrate carrying the color toner images specularly reflects off
the substrate. Some of the light goes into the paper, scatters
around, and comes back out in various directions. Some comes
through the toner and some does not. Because the toner surface is
rough or irregular some of the light incident thereon is reflected
off the toner in various directions. Some of the light incident on
the irregular toner surfaces passes through the toner into the
paper and comes back out in various directions. White light becomes
colored due to selective absorption as it passes through toner. The
light then goes into the paper and back out through the toner
whereby it becomes more colored through more absorption. Any white
light that does not pass through the toner diminishes the
appearance of the final print.
[0021] Attempts to make up for this deficiency in conventionally
formed color toner images have led to the lamination of xerographic
images on paper using a transparent substrate. This procedure has
only been partially successful because the lamination process tends
to reduce the density range of the print, resulting in a print that
has less shadow detail. The lamination process also adds
significant weight and thickness to the print.
[0022] Additionally, it is believed that the aforementioned
lamination process does not produce good results because the color
toner images at the interface between the laminate and the toner
typically do not make suitable optical contact. That is to say, the
initially irregular toner image at the interface is still irregular
enough after lamination (i.e., contains voids) that light is
reflected from at least some of those surfaces and is precluded
from passing through the toner. In other words, when there are
voids between the transparency and toner image, light gets
scattered and reflected back without passing through the colored
toner. Loss of image contrast results when any white light is
scattered, either from the bottom surface of the transparent
substrate or from the irregular toner surfaces and does not pass
through the toner.
[0023] Digital OTC identification documents of the types mentioned
above generally comprise highly plasticized poly (vinyl chloride)
or have a composite structure with polyester laminated to highly
plasticized 0.5-2.0 mil (13-51 .mu.m) poly(vinyl chloride) film,
which provides a suitable receiving layer for heat transferable
dyes which form a photographic image, together with any variant or
invariant data required for the identification of the bearer. These
data are subsequently protected to varying degrees by clear, thin
(0.125-0.250 mil, 3-6 .mu.m) overlay patches applied at the
printhead, holographic hot stamp foils (0.125-0.250 mil, 3-6
.mu.m), or a clear polyester laminate (0.5-10 mil, 13-254 .mu.m)
supporting common security features; these last two types of
protective foil or laminate are applied at a laminating station
separate from the printhead. The choice of laminate dictates the
degree of durability and security imparted to the system in
protecting the image and other data. Although such OTC documents
are in wide use throughout the world, they suffer from several
disadvantages. Both the highly plasticized poly(vinyl chloride)
type and the polyester/poly(vinyl chloride) composite type become
embrittled over time because of migration of the plasticizers, thus
reducing the resistance of the document to cracking. Such cracking
renders the card unusable and vulnerable to tampering.
[0024] The data described above which are crucial to the
identification of the bearer are often covertly repeated on the
document in encrypted form for data verification in a magnetic
stripe, bar code, radio frequency module, or integrated circuit
chip. The inability to retrieve such data due to cracking renders
the document invalid. In addition, many of the polyester/poly(vinyl
chloride) composite documents have exhibited extreme sensitivity to
combinations of heat and humidity, as evidenced by delamination and
curling of the document structure.
SUMMARY OF THE INVENTION
[0025] The present invention is designed to alleviate the foregoing
problems associated with manufacturing a security identification
card or badge using an imaging system such as an ink-jet printer or
electrophotographic copier to obtain a card or badge that is
essentially tamper resistant.
[0026] It is an object of this invention to provide a superior
imaging system that will faithfully reproduce an image without
distortion due to bleeding, running, or the like.
[0027] It is a further object of the invention to provide an
image-receiving layer that can be imaged by a multitude of imaging
processes and materials thereby eliminating the need for multiple
inventories of recording sheets or recording sheets coated on both
sides with media-specific formulations.
[0028] It is a still further object of the invention to provide a
fast-drying image receiving layer that will allow for rapid
reproductions without the potential for smudging of the image.
[0029] A still further object of the invention is to provide a
process to laminate a protective coating onto the imaged surface
without distorting the image itself or its receiver layer or
substrate elements.
[0030] It is another object of the invention to provide an
identification card that cannot be falsified by delamination, image
modification and then reassembly.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] A complete understanding of the present invention may be
obtained by reference to the accompanying drawings, when considered
in conjunction with the subsequent detailed description, in
which:
[0032] FIG. 1 is a cross-sectional representation of the first
integral element;
[0033] FIG. 2, is a cross-sectional representation of the second
integral element; and
[0034] FIG. 3, is a cross-sectional representation of the two
integral elements after the imaging and during the lamination
process.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0035] Generally speaking, a method is described for manufacturing
an identification document that can contain both common and unique
information describing the specific document holder. The present
invention encompasses a process for manufacturing a recording media
that is capable of being imaged by multiple imaging technologies
and to generating an article that is designed to reduce the
potential that it can later be illicitly duplicated or modified.
Such imaging technologies include, but are not limited to, thermal
transfer, ink-jet printing or plotting, screen printing,
handwriting with ink pens (either aqueous or nonaqueous based
inks), offset printing such as lithographic, gravure and intaglio
printing, and printing or copying by electrographic, xerographic,
color or black and white electrophotographic (using either liquid
or dry toners), and laser printing.
[0036] As is well understood in the art, the design of such a
recording medium presents great difficulties for accurate,
high-quality reproductions because the various imaging technologies
in many ways require diametrically opposed chemical and physical
properties, especially for the receiving layer. As an example,
ink-jet receiving layers need to be porous and inherently soft to
allow for rapid absorption of the ink solvent, while
electrophotographic receiving layers must be sufficiently hard to
survive the heat treatment necessary to fuse the toner particles.
Some imaging inks are hydrophobic in nature while others are
aqueous based, therefore the extent of image spreading and rates of
absorption will be vastly different unless careful design of the
image receiving layer is achieved.
[0037] The term "digital identification documents" as used in this
invention is meant to cover not only markings suitable for human
reading, but also markings intended for machine reading. Especially
when intended for machine reading, such an indicium need not be
visible to the human eye, but may be in the form of a marking
visible only under infra-red, ultra-violet or other non-visible
radiation. Thus, the first indicium on the core layer of the
present identification document (and the second indicium discussed
below) may be partially or wholly in the form of a marking visible
only under non-visible radiation. Markings comprising, for example,
a visible "dummy" image superposed over a non-visible "real" image
intended to be machine read may also be used.
[0038] In current ink-jet printing applications, several inks
(typically black, cyan, magenta, and yellow) are used to print
indicia such as textual and graphic information on a printing
medium, typically ordinary paper. The typical ink-jet inks are
primarily composed of a high boiling solvent or are aqueous based,
and contain a colorant that may be either a dye or pigment
dispersion. Pigment dispersions are preferred since the dyes are
highly soluble and tend to smear upon handling. Pigment dispersions
offer improved water and smear resistance as well as better light
stability.
[0039] The aqueous-based inks generally also contain a polyhydric
alcohol to prevent nozzle clogging, and may contain various
adjuvants. Such inks and ordinary paper are well suited for
desk-top publishing as currently practiced, wherein only a small
portion of the paper receives printed text and graphic information.
In order to provide "photoreal" ink-jet prints recording media have
been designed wherein a highly glossy support is coated with a
transparent polymeric material that allows limited lateral
diffusion of the image but still provides rapid absorption of the
solvent.
[0040] Examples of typical image receiving materials include
modified polyethylene oxides, gelatin, polyurethane, polyacrylates,
polyesters, polyamides, polyurethane/urea resins, hydrophilic
acrylic resin, epoxies and mixtures thereof. Most preferred are
modified polyethyleneoxides, polyurethane, polyurethane/urea,
hydroxyethyl cellulose (HEC), cationic polyurethanes and polyvinyl
pyrrolidinone (PVP)/vinyl acetate (VA) copolymers. These receiving
layers may be hardened with such standard cross-linking agents as
formaldehyde and formaldehyde generating compounds such as
oxazolidines, activated double bonded compounds such as vinyl
sulfones, or acrylates, aziridines, and epoxides. It is also known
to coat an underlayer beneath the image receiving layer in order to
act as a reservoir for the absorbed solvent, thereby increasing the
rate of solvent absorption and reducing smearing.
[0041] The substrate, also commonly known as a support or base, is
a material having sufficient stiffness and dimensional stability to
support a printed image without having the image distort or
misalign, and sufficient water resistance that it can be exposed to
an aqueous ink without warping or shrinkage. The material also must
withstand heat and pressure applied during the further lamination
steps described below. The substrate can be of any effective
thickness. The support typically has a thickness of about 25 to
about 250 micrometers (1.0 to 10 mils), preferably about 50 to 200
micrometers (2 to 8 mils).
[0042] The recording media of the present invention comprise a
substrate and an image receiving coating layer on one or both
surfaces of the substrate. Any suitable substrate can be
employed.
[0043] Usable examples of the base material sheets in the image
recording sheets according to the present invention can include
paper, plastic films, glass, fabrics, wood, and metal in either
roll or sheet format. Exemplary paper media include high-quality
paper (i.e., wood-free paper), medium-quality paper (i.e., paper
made of at least 70% chemical pulp and the remainder of groundwood
pulp), coated paper, cast-coated paper or synthetic paper treated
to be water-resistant.
[0044] Suitable plastic materials include polymeric films such as
polyethylene terephthalate and polyethylene naphthanate,
polyamides, poly (methyl methacrylate), polycarbonates,
fluoropolymers, polyacetals, cellulose triacetate, polycarbonate,
poly(vinyl chloride), polyolefins such as polypropylene,
polystyrene, and polyethylene sheets of 50-250 .mu.m in thickness.
Polyethylene terephthalate films are a preferred support
material.
[0045] Examples include transparent materials such as polyester,
polyethylene naphthanates, polycarbonates, polysulfones, polyether
sulfones, such as those prepared from 4,4'-diphenyl ether, those
prepared from disulfonyl chloride, those prepared from biphenylene,
poly (arylene sulfones), such as those prepared from cross-linked
poly(arylene ether ketone sulfones), cellulose triacetate,
polyvinylchloride, cellophane, polyvinyl fluoride, polyimides, and
the like, with polyester such as Mylar.RTM. being preferred in view
of its availability and relatively low cost. The substrate can also
be opaque, including opaque plastics and filled polymers.
[0046] Preferred films include, mono- and biaxially-oriented films
made from polypropylene, polyester, polyamide and the like due to
their superior dynamic property, heat resistance, and transparency.
In particular, biaxially-oriented polyester films are superior in
mechanical strength, heat resistance, chemical resistance, and
dimensional stability so that they have been used in a wide range
of other applications, such as a base film for magnetic tape, an
insulating tape, a photographic film, a tracing film, a food
packaging film and the like. On the other hand, since polyester
films generally have poor adhesive property, it is common practice
to subject a polyester film to a corona discharge surface treatment
or to form an anchor or primer coating layer when additional layers
comprising organic thermoplastic resins or elastomers are going to
be applied to the surface of the polyester film.
[0047] The polyester resins that can be used in the present
invention are those prepared by polycondensation of an aromatic
dicarboxylic acid or an ester thereof, such as terephthalic acid,
isophthalic acid or naphthalenedicarboxylic acid, with a glycol
such as ethylene glycol, diethylene glycol, 1,4-butanediol or
neopentyl glycol. These polyester resins can be prepared, for
example, by direct reaction of an aromatic dicarboxylic acid with a
glycol, or by ester interchange of an aromatic dicarboxylic acid
alkyl ester with a glycol and then polycondensation, or by
polycondensation of an aromatic dicarboxylic acid diglycol ester.
Typical examples of the polyesters include polyethylene
terephthalate, polyethylenebutylene terephthalate and
polyethylene-2,6-naphthalate. These polyesters may be homopolymers
or copolymers with additional monomers. In any case, preferred
polyesters which can be used in the present invention contain
ethylene terephthalate units, butylene terephthalate units or
ethylene-2,6-naphthalate units at a ratio of 70 mol % or higher,
preferably 80 mol % or higher, and more preferably 90 mol % or
higher. The preferred polyester is amorphous or biaxially oriented
poly(ethylene terephthalate).
[0048] For the recording media of the present invention,
void-containing films may also be used as the base film, more
preferably void-containing polyester films. The void-containing
films may be either single-layer films or laminated composite
films.
[0049] The void-containing film which can be used in the present
invention should have an apparent specific gravity of from 0.5 to
1.3 both inclusive, preferably from 0.9 to 1.3 both inclusive, and
more preferably from 1.05 to 1.27 both inclusive. If the apparent
specific gravity is lower than 0.5, the content of voids in the
film is so high that the film shows a marked lowering in strength
and some cracks or wrinkles are liable to occur on the film
surface. In contrast, if the apparent specific gravity exceeds 1.3,
the content of voids in the film is so low that physical properties
attained by the incorporation of voids, such as cushion effect and
flexibility, are deteriorated. The method for lowering the apparent
specific gravity is not particularly limited but, the use of
recording polyester films containing microvoids in the inside is
preferred, where films can be prepared by mixing a polyester resin
with any resin incompatible in the polyester resin and/or with any
inert particulate matter, followed by extrusion and then at least
one-way orientation. In this case, the incompatible resin and inert
particulate matter may be any of those known in the art.
Polystyrene resins and inorganic particles such as titanium dioxide
powder and calcium carbonate powder are preferred.
[0050] Rubber substrates comprising such materials as natural
rubber or synthetic rubbers are all useful in the present
invention. Rubber materials in the present invention are defined by
those materials having a Tg below about 400.degree. C. Synthetic
rubbers include: butadiene rubber, chloroprene rubber, silicone
rubbers, neoprenes, polysulfides, polyacrylate rubbers,
epichlorohydrin rubbers, fluoroelastomers, chlorosulfonated
polyethylene, halogenated butyl rubber, chlorinated polyethylene
rubber, polyurethane rubber, isobutylene-isoprene rubber,
nitrile-butadiene rubber, ethylene-propylene copolymer,
ethylene-propylene-diene terpolymer, styrene-butadiene rubber, and
thermoplastic rubbers. Styrene-butadiene rubber is highly
preferred. To achieve high reflectivity the rubber substrate can
optionally have beads impregnated into the rubber matrix or
embedded in the side to be coated and imaged. Especially preferred
are glass beads of a size range between submicron and 50 micron.
The glass beads can be composed of all compositions of glass as is
known in the art, particularly preferred are silicate-containing
glasses. In a preferred embodiment of the present invention, the
substrate 10 is composed of a glass bead impregnated SBR sheet
approximately less than 35 mil thick, comprising beads being
approximately 30 microns in diameter and with a coverage of between
about 1 to about 60 gm/m.sup.2. Most preferred coverage of glass
beads is between about 3 and about 25 gm/m.sup.2.
[0051] Thin metal sheets may be selected, as well as metallized
polymeric films selected from those described above are also within
the scope of the present invention.
[0052] The substrate may be colored and can have components, such
as antihalation dyes incorporated therein to meet the needs of
specific applications. In a preferred embodiment the support
material is opaque and has sufficient flexibility to be bent
without cracking or causing delamination of overcoated layers. The
base support may optionally contain a pretreatment to its surface
to promote such properties as adhesion between the applied coatings
and base or an anti-static agent to dissipate electrostatic
buildup, or the base may be supplied without any pretreatment
coating. Prior to coating, the support may be subjected to corona
discharge treatment, plasma treatment, undercoating treatment, heat
treatment, dust removing treatment, metal vacuum deposition
treatment, or alkali treatment.
[0053] In another preferred embodiment of the present invention,
the support layer is printed with indicia or embossed with a
holographic image that can be detected through later-coated
transparent layers.
[0054] In other preferred embodiments of the present invention,
other security features containing crucial data relating to the
identification of the bearer are often covertly applied to the
inventive laminate in encrypted form for data verification in a
magnetic stripe, bar code, radio frequency module, or integrated
circuit chip. This information may be imaged onto the later
described image recording layers 50 and 50a (FIG. 2). In a highly
preferred embodiment, invariant data is imaged onto one layer while
variant (individualized) data is imaged onto the second layer.
[0055] If the present invention is to be used as an identity card
or a credit card, it is highly desirable that the base allow for
bending forces without cracking or delaminating.
[0056] In certain embodiments of the present invention, it is
desirable to provide an adhesive layer to the distal side of the
substrate relative to the image receiving side. For example, if the
imaged product is to be used as a tag for license plates or to be
affixed to other objects it is beneficial to provide an adhesive
surface. The adhesive layer can furthermore have a protective layer
that is removable by peeling so that premature adhesion to
undesirable articles is prevented. This is highly desirable even
within the present manufacturing process especially the later
lamination step which requires, as shown in FIG. 3, the
intermediate articles 100 and 200 to be pressed together between
rollers or platen 400 and 400a at room temperature or elevated
temperatures and atmospheric or elevated pressures.
[0057] As shown in FIG. 1, an optional primer also known as an
anchoring layer 20 can be applied if necessary, providing adhesion
of overcoated layers to the base material sheet or roll 10. The
primer composition preferably should be transparent, especially in
the embodiment where high reflectivity is required from the base
support 10. It is also within the scope of the present invention to
allow the support to optionally be corona treated prior to applying
either a primer layer 20 or a later described undercoat layer
30.
[0058] An anchor or primer layer 20 may be used to ensure adequate
adhesion of the support 10 to any layers coated onto its major
lateral surfaces. The term "anchor layer," as employed in the art,
means a layer that is adhesively bonded to the layers on both sides
of it. Adhesive materials for bonding different types of materials
are well known in the art. Any conventional adhesive material can
be used in the anchor layer, or layers, providing that it is not
adversely affected by the later coating, imaging, and laminating
steps.
[0059] Representative materials include ethylene/vinyl acetate
copolymers, ethylene/acrylic acid copolymers, vinyl chloride/vinyl
acetate copolymers, vinyl chloride/vinylidene chloride copolymers,
thermoplastic polyamides, and the like. The choice of adhesive will
depend on the compositions of the underlayer 30 and the support 10
(FIG. 1). The anchor layer or layers may contain materials such as
antistats, colorants, antihalation dyes, optical brighteners,
surfactants, plasticizers, coating aids, and the like. The anchor
layer(s) generally has a thickness in the range of 0.01 to 10
micrometers, preferably 0.05 to 5 micrometers.
[0060] As such anchor coating agent, a number of materials have
been proposed, among which are water soluble or water dispersible
polyester or acrylic resin to be used for a film having
comparatively higher polarity, which is typically a polyester film
(e.g., see U.S. Pat. No. 4,098,952, issued to Kelly et al. on Jul.
4, 1978 for COATED POLYESTER FILM ASSEMBLY WITH A PRIMER
LAYER).
[0061] In the present invention, the preferred primer layer coating
materials include ethylene vinyl acetate and ethylene acrylic acid
polymers. Another preferred primer layer composition is methyl
methacrylate/2-hydroxyethyl methacrylate graft.
[0062] Other optional coating layers can be applied after the
primer layer. These include such layers as a lubricant layer, which
improves the coefficient of friction. They can be applied to the
back (lower) side of the base material sheet, said back side being
on the non-imaged side of the support. An anticurl layer can also
be coated on the backside of the support.
[0063] As shown in FIG. 1, an undercoat layer 30 separates the
support surface from the image-receiving layer 50. The undercoat
layer may be either a hydrophilic polymer or hydrophobic polymer or
a combination of both. These polymers are film-forming plastics and
are resinous agents that are considered binders, which contribute
several important characteristics to the coating composition. The
binders provide adhesion to the base support, thicken the coating
composition, serve as a carrier for optional particulate fillers,
and among other functions, provide absorptive properties for
printing/imaging solvents. In the present invention this layer also
must be readily softened at elevated temperatures in order to
provide irreversible bonding during later lamination manufacturing
steps. Although not a requirement, it is highly preferred that the
undercoat layer be provided from essentially an aqueous media, the
polymer either being soluble within the aqueous media or in the
form of a latex or dispersion particle. Typical dispersion particle
size ranges from submicron to about 80 micron. During the coating
and drying of this layer, the dispersion particles will coalesce to
provide a clear, continuous film. It is also possible to employ
polymers that can be readily miscible in alcohol, ketones, and/or
glycol ether solvent systems however solvent capture, recovery,
reuse become problematic.
[0064] Desirable hydrophilic, water-soluble polymers include
polyvinyl pyrrolidone and its copolymers, including: a) polyvinyl
pyrrolidone, polyvinyl pyrrolidone/polyvinyl acetate copolymers,
polyvinyl pyrrolidone/styrene, polyvinyl
pyrrolidone/dimethylaminoethylmethacrylate copolymers; b)
polyacrylic acid and its copolymers, including polyacrylic acid,
and polyvinyl pyrrolidone/polyacrylic acid; c) polyvinyl acetal, or
polyvinyl butyral; and d) polyvinyl alcohol. These hydrophilic,
water soluble polymers are preferred due to their absorbency of the
ink-jet printer's ink vehicle. A desirable hydrophilic,
water-soluble polymer is polyvinylpyrrolidone
dimethylaminoethyl-methacrylate (a PVP copolymer).
[0065] The hydrophilic, water-soluble polymer of the present
invention is generally present in the amount from approximately 5
to approximately 60 percent by weight of the total dried coating.
Desirably, the hydrophilic, water-soluble polymer is generally
present in the amount from approximately 15 percent to
approximately 45 percent.
[0066] Any resin having hydrophobic properties can be used as the
hydrophobic resin contained in the undercoat layer 30. Examples of
the hydrophobic resin include, but are not limited to, acrylic
resins, polyester resins, polyurethane resins, styrene-acrylic
copolymer resins, styrene-butadiene copolymer resins,
acrylonitrile-butadiene copolymer resins, vinyl acetate resins,
vinyl chloride resins, ethylene-vinyl acetate copolymer resins,
vinyl chloride-vinyl acetate copolymer resins, silicone resins,
nitrocellulose resins, alkyd resins, polyvinyl butyral resins,
polycarbonate resins. Resins suitable for use in the present
invention must have Tg below about 60.degree. C.
[0067] In a preferred embodiment the undercoat comprises a
hydrophobic polyurethane layer provided from an aqueous
polyurethane dispersion (PUD). The type of polyurethane employed in
the present invention is not critical. Aliphatic and aromatic types
are suitable although the aliphatic type is preferred particularly
since it produces a non-yellowing film. The terms "aliphatic" and
"aromatic" are used in the conventional sense in the art and refer
to the "hard" segments of the polymer that are provided by
aliphatic or aromatic isocyanates or diols. The PUD can be either
anionic, nonionic, or cationic but anionic and nonionic PUDs are
preferred. Preferably, what is known in the art as a water-borne
polyurethane is employed. Such polyurethane compositions are not
solely organic solvent solutions but rather are made up of solvent
systems that include a predominant amount of water. Thus, a typical
water-borne polyurethane would consist of 30% (solids)
polyurethane, 15% N-methylpyrrolidone, and 55% water.
[0068] Preferred in the current invention are nonionic and anionic
polyurethane dispersions. It should be understood, however, that
polyurethanes in organic solvents can be employed in the present
invention provided the solvent is selected to avoid an
incompatibility with the specified water-dispersible polymer and
that the solvent does not etch or otherwise attack the substrate
layer. It is critical that for the current invention the Tg of the
polyurethane resins selected for use in the undercoat have Tg
values less than approximately 60.degree. C. A preferred adhesive
material is based on aqueous polyurethane dispersions as described
in U.S. Pat. No. 5,494,960, previously referenced, and 5,637,639,
issued to Duan et al. on Jun. 10, 1997 for REDUCED SOLVENT PROCESS
FOR PREPARATION OF AQUEOUS POLYURETHANE DISPERSIONS WITH IMPROVED
HEAT- AND WATER-RESISTANCE.
[0069] PUDs serve a unique and dual function in the present
invention. As an underlayer to the image-recording layer they act
as a reservoir to absorb solvent during the imaging process. This
allows the image-recording layer 50 to rapidly absorb the solvent
thereby reducing drying time. Secondly, in the later lamination
step, the PUD will melt, thereby permanently affixing the
image-recording layer 50 to the substrate 10, FIG. 1. In this
manner the PUD acts as a thermal adhesive. Significantly and most
importantly, the melting of the PUD maintains the image in its
original geometry (i.e., there is no distortion of the applied
image).
[0070] In other embodiments of the invention it is possible to
further employ water-based polyisocyanates as catalyst hardeners to
cure the water-based polyurethane dispersions described above. The
polyisocyanate can be formulated within the underlayer 30 or as a
separate layer adjacent to the underlayer 30.
[0071] If higher Tg polyurethane resins are selected then they must
be mixed with compatible polymer resin plasticizers, having lower
Tg, to form a clear, transparent underlayer 30. Such preferred
plasticizers known in the art will not diffuse into the later
formed imaging layer 50 (FIG. 1). Concentrations of these
plasticizers can be up to about 16% the weight of the undercoat
resin coat weight. Examples of useful plasticizers include DOP,
PEG, glycerol, trimethylol propane, and other plasticizers known in
the industry. Additionally, optional tackifiers may be incorporated
into the plasticizer formulation to improve flexibility and heat
sealability.
[0072] The undercoat layer 30 preferably is transparent to allow
maximum reflectivity from the base support 10 (FIG. 1). In one
preferred embodiment of the present invention, the use of polymeric
beads such as ethylene-acrylic acid copolymer can be added to the
undercoat layer 30. The beads must have a Tg that will allow the
beads to melt into the undercoat layer during the later laminating
step and also not impair the transparency of the undercoat layer.
It has been demonstrated when these conditions are met, improved
adhesiveness to adjacent layers 20 and 40 can be achieved. A
preferred addition range for these beads is 0 to about 50
gm/m.sup.2. The use of polymeric beads as described in this layer
can also be beneficial when used in other later described
layers.
[0073] An optional barrier layer, preferably composed of
polyurethane, separates the image-receiving layer 50 from the
undercoat layer 30. The polyurethane for this layer is provided
from a solvent-based polyurethane latex.
[0074] The function of this barrier layer 40 is to protect the
undercoat layer 30 and the support 10 from attack by solvents from
later-applied solvent-based coatings and imaging formulations.
Organic solvents which can be used in dispersion, kneading, or
coating in the present invention include: ketones such as acetone,
methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone,
isophorone, and tetrahydrofuran; alcohols such as methanol,
ethanol, propanol, butanol, isobutyl alcohol, isopropyl alcohol,
and methylcyclohexanol; esters such as methyl acetate, ethyl
acetate, butyl acetate, isobutyl acetate, isopropyl acetate, ethyl
lactate, and acetic acid glycol monoethyl ether; ethers such as
diethyl ether, tetrahydrofuran, glycol dimethyl ether, glycol
monoethyl ether, and dioxane; aromatic hydrocarbons such as
benzene, toluene, xylene, cresol, chlorobenzene, and styrene;
chlorinated hydrocarbons such as methylene chloride, ethylene
chloride, carbon tetrachloride, chloroform, ethylene chlorohydrin,
and dichlorobenzene; and N,N-dimethylformaldehyde. These solvents
can be used in any desired proportions.
[0075] The barrier layer is applied as a very thin coating,
typically 1 to 60 gm/M.sup.2, and preferably 1 to 10 gm/m.sup.2 and
is dried rapidly to prevent disruption of the underlayer 30.
Disruption would generally cause unfavorable levels of haze thereby
reducing the reflectivity from the glass beads located in the base
support 10 (FIG. 1).
[0076] Preferred solvent-based polymeric compositions for the
current invention include polyurethane dispersions, composed of a
non-reactive linear polyurethane lacquer dissolved in a mixture of
organic solvents. Other lacquers or polyurethanes possessing
approximately the same tensile strength and flexibility as the
protective layer can also be employed.
[0077] The image-recording layer 50 shown in FIG. 1 is constructed
of an essentially hydrophilic polymer composition having a balance
of properties. The layer 50 traps the imaging material applied
during the imaging process. If the imaging is performed via ink-jet
application, the ink, whether from organic dye or from pigment
contained in the ink, is trapped in layer 50. In this situation the
image-recording layer 50 can be referred to as an ink-receiving
layer 50. Layer 50 however is sufficiently permeable to the ink
carrier medium (i.e., water that optionally contains liquid organic
additives) that the carrier quickly passes through the
ink-receiving layer 50 to the water-absorbing layer 30. Rapid
transfer of the aqueous carrier is important to achieve desired
printing speeds.
[0078] It is desirable that the image-recording layer 50 not be so
tacky at ambient temperatures that it presents a handling problem.
However, materials should be avoided that are so slippery the
material presents a registration problem during lamination to the
protective construct. For many applications, it will be desirable
to employ an image-receiving layer that is scratch and
abrasion-resistant when wet or dry, and is resistant to cracking or
embrittlement over time.
[0079] The present invention carefully balances two critical
parameters. It is imperative the image be formed in a manner
allowing rapid uptake of any non-imaging solvent (i.e., the image
receiving layer must be highly absorbent); therefore, it cannot be
too "hard." Alternately, this layer must also survive the later
lamination step requiring elevated temperatures and cannot be too
soft. In addition, when the present invention is used in
combination with ink-jet inks, it is highly preferred that the
ink-jet dyes not diffuse laterally through the layer. This
requirement can be fulfilled by employing optional cationic sites
to the polymers comprising the image-recording layer 50.
[0080] In one embodiment the image-recording layer 50 comprises
modified polyalkylene oxide polymers. The polyalkylene oxide
portion of these polymers may be homopolymers, random or block
heteropolymers comprising two or more alkylene oxide monomers such
as ethylene oxide or propylene oxide. In this invention the
molecular weight range for useful polyethylene oxide polymers is
approximately 50,000 to about 3,000,000 Daltons. Preferred
molecular weights are between about 70,000 and 1,000,000 Daltons,
and most preferred molecular weights are between 100,000 and
200,000 Daltons. Modification to these polymers is achieved by
reacting the polyalkylene oxide polymers with reactive siloxanes to
convert at least a portion of the end capped hydroxyl
functionalities on the polyalkylene oxide polymers.
[0081] In a preferred embodiment of the present invention the use
of nonionic surfactants such as glycidyl oils can be used as
emulsifying agents to form the modified polyalkylene oxide
polymers. Materials of this type are described in U.S. Pat. No.
6,143,419 issued to Hanada, et al. on Nov. 7, 2000 for INK-JET
RECORDING SHEET COMPRISING A MOLECULE CONTAINING TERTIARY AMINO
GROUPS AND POLYSILOXANE SEGMENTS. It has been determined that to
achieve the combination of desired effects described above, the
siloxane-modified polyoxyalkylene oxide materials of the present
invention must have a Tg between about 56.degree. C. and
130.degree. C. This is typically achieved by having the ratio of
siloxane moiety to alkyleneoxide be approximately 0.5% to 20% of
the entire resin, preferably between 10% and 20%.
[0082] In a most highly preferred embodiment of the present
invention the siloxane functionality also can be converted in later
steps into cationic moieties. Such groups include isocyanate or
carboxylic acids that upon reaction with amines can generate
quaternary ammonium salts. When attached to the siloxane
derivatized polyalkylene oxide, these quaternary ammonium salts
provide sites for ionically complexing with anioinic ink-jet dyes
preventing lateral diffusion and thereby providing high quality,
high resolution images.
[0083] The siloxane-modified polyethylene oxide polymers of the
present invention should not be confused with prior art using
modified polyalkylene glycols (MPEGs) that typically act as
plasticizers, or specialty oils to modulate flow, viscosity,
leveling, and drying characteristics of the coating composition.
Prior art MPEGs typically comprise lower weight PEG materials with
molecular weights from approximately 200 to 10,000 and have also
been used as nonionic surfactants to facilitate coating uniformity,
and are designed to consist of a high ratio of siloxane groups
compared to alkylene oxide groups. Therefore, these prior art MPEGs
are typically hydrophobic and have a slight hydrophilicity due to
the few alkylene oxide groups.
[0084] In the current invention the modified polyethylene oxides
are used for an entirely different function and do not behave as
the prior art materials. Specifically, the present modified
polyethylene oxides as used in the present invention are applied in
a solvent formulation and the function of the thus coated modified
polyethylene oxide polymers is to act as a receiving or recording
media for the later imaging process. In this case the desire is to
have a predominantly hydrophilic material that will allow rapid
aqueous solvent absorption yet be marginally hydrophobic in order
to entrap the imaging material. Therefore, the ratio of siloxane to
alkylene oxide moieties is intentionally kept to a minimum.
Unexpectedly, these modified polyethylene oxide materials provide
means to affix organic dyes and pigments, inorganic pigments, or
toner particles. In this manner, highly reproducible images can be
generated. Furthermore, of significant importance to the present
invention is that the imaged polyethylene oxide image recording
layer 50 (FIG. 1) faithfully reproduces an applied image and
maintains that faithful reproduction through the later laminating
process.
[0085] As the resin component constituting the ink-receiving layer,
the resin in the first aspect, or the resin in the second aspect
can be used singly. Depending on the composition of an ink-jet
recording ink, a water-soluble polymer may also be used in
combination with the above-described resin with a view to
additionally imparting hydrophilicity and/or water absorbency or to
adjusting the same.
[0086] Usable examples of the water-soluble polymer can include
polyvinyl alcohol, modified polyvinyl alcohol,
hydroxyethylcellulose, CMC, cellulose derivatives,
polyvinylpyrrolidone, starch, cationized starch, gelatin, casein,
and acrylic acid polymers.
[0087] Further, a hydrophobic polymer may also be used in
combination with the above-described resin with a view to further
imparting water-proofness and durability to the ink-receiving layer
and printed marks. Usable examples of the hydrophobic polymer can
include commonly-used synthetic resins such as polyester resins,
poly(vinyl chloride) resin, polystyrene resin, poly(methyl
methacrylate) resin, polycarbonate resins, polyurethane resins,
vinyl chloride-vinyl acetate copolymer resins,
acrylonitrile-styrene copolymer resins, polyvinyl butyral resin,
polyamide resins, epoxy resins, urea resins, and melamine
resins.
[0088] In a highly preferred embodiment of the present invention,
the coating formulation of the image-recording layer comprises a
mixture of siloxane-modified polyalkylene oxide (described above),
and an acrylic acid/acrylate copolymer. The amount of the acrylic
acid/acrylate copolymer can range from approximately 3 to 30
weight/weight percent in the image-recording layer 50.
[0089] The image-recording layer 50 typically has a thickness of
0.1 to 10 mils, preferably about 0.6 to 0.8 mils, and can
optionally contain at least 20% adhesive having the properties
described for the undercoat layer 30, based on total weight of the
layer. Preferably the adhesive will constitute at least 80% of the
layer.
[0090] The image-recording layer 50 may optionally be toughened
with 0.5 to about 8% by weight of known cross-linking agents. A
cross-linking agent selected from the group consisting of aldehyde
compounds, ketone compounds, a triazine compound, reactive
halogen-containing compounds, divinylsulfone, a carbamoyl
pyridinium compound, reactive olefin-containing compounds,
N-methylol compounds, isocyanates, aziridine compounds,
carbodiimides, epoxy compounds, a halogencarboxyaldehyde, a dioxane
derivative, chromium alum, potash alum, zirconium sulfate and boric
acid, hexamethoxymethyl melamine, methylated melamine-formaldehyde,
methylated urea-formaldehyde, cationic urea-formaldehyde, cationic
polyamine-epichlorohydrin, glyoxal-urea resin, poly (aziridine),
poly (acrylamide), poly (N,N-dimethyl acrylamide),
acrylamide-acrylic acid copolymer, poly (2-acrylamido-2-methyl
propane sulfonic acid), poly (N,N-dimethyl-3,5-dimethylene
piperidinium chloride), poly (methylene-guanidine) hydrochloride,
poly (ethylene imine) poly (ethylene imine) epichlorohydrin, poly
(ethylene imine) ethoxylated, and glutaraldehyde.
[0091] The cross-linking agents can be mixed with the
image-recording coating formulation prior, simultaneous with, or as
a post treatment after coating. Another useful family of
cross-linking agents is polyepoxides.
[0092] Various polymeric isocyanates can also be used as
cross-linking agents. In particular, MEI can be used as a
cross-linking agent, in this case water (primarily from the ink
formulations), can assist in forming urea cross-links.
[0093] Other preferred hardening agents are polyvalent metal salts
of organic acids, e.g., particles consisting of aluminum,
zirconium, titanium and mixtures thereof. Most preferred is
zirconium propionate.
[0094] When forming the image-recording layer 50 of the present
invention, it can also contain certain additional modifying
ingredients, such as adhesion promoters, matte particles,
surfactants, viscosity modifiers, mordants, and like materials,
provided that such additives do not adversely affect the ink or
toner-receptivity of the layer.
[0095] As fillers or pigments and resin particles for use in the
image recording layer, one or more pigments and resin particles can
be suitably chosen in accordance with the quality design of the
ink-jet recording sheet from known pigments and resin particles,
e.g., mineral or porous pigments such as kaolin, delaminated
kaolin, aluminum hydroxide, silica, diatomaceous earth, calcium
carbonate, talc, titanium oxide, calcium sulfate, barium sulfate,
zinc oxide, alumina, calcium silicate, magnesium silicate,
colloidal silica, zeolite, bentonite, sericite and lithopone; and
fine particles, porous fine particles, hollow particles and the
like of polystyrene resin, urea resins, acrylic resins, melamine
resins, benzoguanamine resin, polyurethane resins, and other
organic pigments. In this case, these pigments and resin particles
are added in a range from 0 to 95 wt. %, preferably from 10 to 90
wt. % based on the whole solid content of the ink-receiving
layer.
[0096] Besides the resin and pigments, various additives can also
be incorporated in the ink-recording layer as needed. These
additives can include thickening agents, parting agents,
penetrating agents, wetting agents, thermal gelling agents, sizing
agents, defoaming agents, foam suppressers, blowing agents,
coloring matters, fluorescent whiteners, ultraviolet absorbers,
oxidation inhibitors, quenchers, antiseptic agents, antistatic
agents, cross-linking agents, dispersants, lubricants,
plasticizers, pH regulators, flow improvers, setting promoters, and
waterproofing agents, humectant, UV absorber, polymeric dispersant,
defoamer, mold inhibitor, latex, and dye mordant.
[0097] In an embodiment of the present invention, the image
recording layer is a cast-coated layer prepared by coating a
coating liquid for the cast-coated layer on a surface of the
undercoated substrate sheet; press-casting, while the resultant
coating liquid layer on the substrate sheet surface is kept in a
wetted condition, the coating liquid layer onto a mirror-finished
peripheral surface of a casting drum; drying the press-casted
coating liquid layer on the casting drum; and separating the
resultant laminate from the casting drum.
[0098] The combination of substrate 10 and layers 20, 30, 40, 50,
and 11 comprise intermediate article 100 as depicted in FIG. 1.
[0099] As shown in FIG. 2, a polymeric plastic film 80 is coated
with an adhesive material forming a composite. The material for the
protective plastic overlayer 80 can be selected from the polymeric
materials described for the substrate 10. The plastic film 80 for
the present invention must be transparent. Prior to coating with
adhesive material 60 (described later) the film 80 can be
optionally corona or plasma treated to improve adhesion and further
can be treated with an antistat. An optional primer layer 70 can
also be applied prior to overcoating with the adhesive layer 60.
The composition of the primer layer 70 can be selected
independently from the primers described for layer 20. In a
preferred embodiment the plastic overlayer has been previously
embossed to form holographic images even under diffuse
lighting.
[0100] The protective layer 80 should be resistant to scratching
and cracking due to bending as well as to environmental components
and contaminants. It is permanently adhered to ink-receptive layer
50 through an adhesive layer 60 (described below) and can be
applied by a temporary carrier or transport layer 90 affixed to the
backside of the protective film 80. Protective layer 80 is
transparent in at least one region of the visible spectrum and
typically is transparent throughout the ultraviolet, visible,
and/or infrared spectral regions.
[0101] Protective layer 80 can consist essentially of a
fluoropolymer, a saran, polyvinyl chloride, a polyester or an
acrylic polymer. Fluoropolymer refers to a polymer whose structure
comprises fluorine atoms covalently bonded to carbon atoms. As is
well known to those skilled in the art, such polymers can be
prepared by polymerization of fluorinated monomers, such as
tetrafluoroethylene, hexafluoropropylene, vinylidene fluoride,
perfluorovinyl ethers, and vinyl fluoride, with each other and/or
with non-fluorinated monomers, such as ethylene. In order to
prevent cracking over time, the protective layer may also contain
plasticizers as are known in the art. Furthermore, the thickness of
the protective layer is preferably selected to be as thin as
possible, typically in the range of 0.1 microns to about 30 microns
in order to withstand bending forces yet thick enough to maintain
integrity from chemical and physical impairment. Preferably, the
thickness of the protective layer 80 is between approximately 0.5
and 10 gm/m.sup.2.
[0102] Protective layer 80 may also contain a photostabilizer to
protect the underlying image from damage by ambient ultra-violet
light. Photostabilizers are well known in the art and include
2-hydroxybenzophenones, oxalanilides, aryl esters and the like, and
hindered amine light stabilizers, such as
bis(2,2,6,6-tetramethyl-4-piperidinyl)sebacate, and combinations
thereof. Optical brighteners that may be used to enhance the visual
appearance of the imaged layer may be any conventional, compatible
optical brightener. To prevent distortion of the underlying image
when it is viewed through the protective layer, materials that do
not absorb strongly in the visible region of the spectrum are
preferred.
[0103] At times it is desired to provide a range of surface
finishes from highly glossy to matte. This may be done by
controlling the outermost surface of protective layer 80 (FIG. 2).
This surface replicates the surface of the temporary carrier layer
90 with which it is in contact prior to lamination and separation.
If the surface of the temporary carrier layer has a rough texture
or contains any other relief pattern, the image will appear matte.
If the surface of the temporary carrier layer is smooth, the image
will appear glossy.
[0104] Alternatively, protective layer 80 may be provided with a
matte surface. This matte surface can be obtained by including in
the layer particles sufficiently large to give surface
irregularities to the layer. Particles of average diameter in the
range of approximately 1 micron to 15 micron are suitable. This
layer typically has a thickness in the range of approximately 0.5
micron to 10 micron and preferably in the range of approximately 1
micron to 4 micron. A preferred matting agent is amorphous
silica.
[0105] Suitable adhesives are well known in the art. The exact
choice will depend on the image-recording layer and the desired
permanent support. Examples of suitable adhesives include polyester
resins, polyvinyl alcohol homopolymers and copolymers (e.g., with,
methyl methacrylate, or vinyl acetate), polyvinyl pyrrolidone, and
blends thereof, and copolymers of vinyl acetate with ethylene
and/or vinyl chloride.
[0106] An optional second image recording layer 50a can be
laminated or overcoated to the adhesive layer 60 described above.
The second image-recording layer is typically composed of materials
described for image recording layer 50. The material selected for
the two imaging layers 50 and 50a can be independently selected but
they must be compatible with each other as they will be in intimate
contact after the later lamination steps. It is desirable that the
imaging processes for each imaging layer 50 and 50a may be either
the same or different, for example either one or both might be
imaged by an ink-jet application or imaged by an
electrophotographic copier. In a preferred embodiment both imaging
layers 50 and 50a are composed of the same material. In a most
preferred embodiment the image-recording layer comprises a modified
polyethylene oxide material.
[0107] The selection of the resin material in the adhesion layer
and its corresponding Tg and second image recording material will
dictate the mode of imaging. For example, higher Tg materials will
be required for the imaging in an electrographic copier due to the
temperatures necessary to fuse the tone particles. Under these
conditions it would be unacceptable for the adhesive material in
the undercoat layer 30 to melt prior to the later lamination
process.
[0108] In a preferred embodiment, the thin upper layer 50 or 50a
further comprises organic acid salts of polyethyleneimine for
optimization of other properties such as drytime, smudging of the
images, image brightness, color quality, tack and bleeding.
[0109] The thickness of the image recording layers 50 and 50a as
described above may preferably be from 0.5 to 50 g/m.sup.2 in terms
of dry weight, with 3 to 20 g/m.sup.2 or so being more preferred.
If the thickness of the image recording or ink-receiving layer is
smaller than 1 g/m.sup.2, the ink-receiving layer cannot exhibit
sufficient ink absorbency. Even if the thickness exceeds 50
g/m.sup.2, no additional beneficial effects are noted. Accordingly,
such an excessively large thickness is not economical and,
moreover, tends to induce fold-cracking, curling, etc. of the
ink-receiving layer.
[0110] An aspect of the present invention that is especially
critical to its success is requiring that the two image recording
layers 50 and 50a readily and accurately affix the applied image
whether the image be digital or analog, and either mechanically or
manually applied. Furthermore, the rendered image must survive
lamination conditions typically performed at elevated
temperatures.
[0111] The present invention allows for the imaging process to be
selected from a broad range of known imaging processes. In general,
such methods include both mechanical and manual applications either
in a digital or analog mode, including but not limited to: ink-jet,
electrographic, thermal transfer, dye diffusion transfer,
thermographic, and conventional printing, or manually applied with
such materials as paint, ink, toner, pigment, or other colored
compositions.
[0112] For the purposes of this invention, the integral element of
the protective layer 80, optional primer layer 70, adhesive layer
60, and optional second image recording layer 50a is termed
construct 200 (FIG. 2). While the integral element of the substrate
10, optional primer layer 20, underlayer 30, optional barrier layer
40, and image recording layer 50 is termed an intermediate
composite 100 (FIG. 1).
[0113] It should be noted that when a second image-recording layer
50a is employed, the first image-recording layer 50 may optionally
be eliminated or alternatively if recording layer 50 is employed
then layer 50a may be eliminated. In this case the intermediate
composite would only include the substrate 10, optional primer
layer 20, underlayer 30, and optional barrier layer 40.
[0114] For the methods of forming the coated elements 100 and 200
of the present invention like the image-recording layer 50,
undercoat layer 30, and all optional layers, ordinary coating
methods such as extrusion, blade coater, air-knife coater, die
coating, direct or reverse roll coater, curtain coater, Mayer wire
wound rod coating, air doctor coating, squeeze coating, dip
coating, reverse roll coating, transfer roll coating, gravure
coating, kiss coating, cast coating, spray coating, bar coating,
spin coating, etc. can be used.
[0115] In one embodiment of the present invention, a so-called
wet-on-wet coating method in which a coating solution for an upper
layer is applied to a lower layer before the lower layer has been
dried. Such coatings can be made simultaneously at one coating
station or sequentially at multiple coating stations in a single or
multiple pass operation. Alternatively, the layers may be coated
separately after being dried and optionally wound and unwound.
[0116] The drying methods for coatings of the inventive film
include drying and solidifying by hot air, infrared rays, and the
like.
[0117] A desirable method of producing the ink receiving media of
the present invention is wire wound Mayer bar coating followed by
oven and air-drying. After the coating, the thus-coated layers may
be finished by using a calender such as a machine calender,
supercalender or soft calender.
[0118] Subsequent to coating, drying, and imaging, the outermost
layers of the construct 100 and the intermediate construct are
brought into contact. For example, the exposed surfaces of 50 and
50a or 60 are brought into intimate contact and then heat is
applied to laminate the two integral elements 100 and 200 to form
an integral single laminate comprising sequentially from substrate
10, an optional primer layer 20, a binder layer 30, an optional
barrier layer 40, an image receiving layer 50, an adhesive layer
60, an optional primer layer 70, and a plastic protective layer 80.
In a most preferred embodiment, the substrate 10 comprises a
rubber-based material having highly reflective glass beads on the
coating surface, the optional primer layer 20 comprises EAA, EVA
(from Tg -50.degree. C. to 130.degree. C.), surlyn, polyvinyl
butral, polyester, polyurethane or blends thereof. The binder layer
30 comprises an aqueous-based polyurethane elastomer, the optional
barrier layer 40 comprises a solvent based polyurethane elastomer,
the image receiving layer 50 comprises a polyethyleneoxide diether,
the adhesive layer 60 comprises polyurethane, the optional primer
layer 70 comprises polyurethane or EVA or a blend thereof, and the
plastic protective layer 80 comprises polyethylene terphthalate
further comprising holographic images. These layers can be applied
by conventional coating methods such as slot die or extrusion in
single-layer or multiple-layer coating operations.
[0119] The lamination process comprises heating the construct 100
and the intermediate composite 200 at 150.degree. F. to 800.degree.
F. for 0.5 seconds to 10 seconds. Lamination typically is performed
at a laminating station separate from the imaging process (e.g.,
ink-jet printhead or electrographic copier.)
[0120] In summary, the present invention is designed to create an
image that has a high degree of permanence, and can withstand
intentional tampering that could otherwise generate illicitly
altered copies. In this regard the invention has significant
utility for personal identification cards, credit cards, and the
like. Embodiments of this aspect of the invention essentially
comprise one or two imaged layers laminated between an opaque
support and a transparent protective surface. By the very nature of
the design, materials of this type are weather and light fade
resistant, making them suitable articles for outdoor display. In
keeping with the aspect of security, one embodiment of the
invention can be utilized for such applications as license plate
tags. In this embodiment an adhesive material is placed on the
backside of the support 10. Typically, this is achieved by having
an inert transport covering on the backside of the support and
having an adhesive material between the transport covering and the
backside of the support 10. After imaging and lamination, the
transport covering is removed to expose the adhesive backcoat on
the support 10. The adhesive backcoat can then affix the laminated
and imaged article to such objects as a license plate. If security
is not a prime factor, the adhesive backcoat can be designed for
facile removal so as to allow for frequent change, as might be the
case in outdoor advertising.
[0121] Since other modifications and changes varied to fit
particular operating requirements and environments will be apparent
to those skilled in the art, the invention is not considered
limited to the example chosen for purposes of disclosure, and
covers all changes and modifications which do not constitute
departures from the true spirit and scope of this invention.
[0122] Having thus described the invention, what is desired to be
protected by Letters Patent is presented in the subsequently
appended claims.
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