U.S. patent application number 11/625394 was filed with the patent office on 2007-05-24 for thermal transfer image receiving sheet and method.
Invention is credited to Dieu Dai Huynh.
Application Number | 20070116905 11/625394 |
Document ID | / |
Family ID | 33032668 |
Filed Date | 2007-05-24 |
United States Patent
Application |
20070116905 |
Kind Code |
A1 |
Huynh; Dieu Dai |
May 24, 2007 |
THERMAL TRANSFER IMAGE RECEIVING SHEET AND METHOD
Abstract
A thermal transfer image-receiving polymeric sheet capable of
recording thereon thermally transferred dye or ink images in a
clear and sharp form. The image-receiving layer comprises at least
one water dispersible aliphatic polyether-polyurethane resin and at
least one water dispersible aliphatic polyester-polyurethane resin
or a silica dispersion or an anionic aqueous emulsion of wax.
Inventors: |
Huynh; Dieu Dai;
(Courcouronnes, FR) |
Correspondence
Address: |
RENNER, OTTO, BOISSELLE & SKLAR, LLP (AVERY)
1621 EUCLID AVE
19TH FL
CLEVELAND
OH
44115-2191
US
|
Family ID: |
33032668 |
Appl. No.: |
11/625394 |
Filed: |
January 22, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10797826 |
Mar 10, 2004 |
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11625394 |
Jan 22, 2007 |
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60454258 |
Mar 13, 2003 |
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60454960 |
Mar 14, 2003 |
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Current U.S.
Class: |
428/32.39 |
Current CPC
Class: |
B41M 5/5218 20130101;
Y10T 428/31855 20150401; B41M 5/5272 20130101; B41M 5/5281
20130101; B41M 5/52 20130101; Y10T 428/254 20150115; Y10S 428/914
20130101; B41M 2205/32 20130101; Y10T 428/31786 20150401; Y10T
428/31551 20150401; Y10T 428/31565 20150401; B41M 5/5227
20130101 |
Class at
Publication: |
428/032.39 |
International
Class: |
B41M 5/40 20060101
B41M005/40 |
Claims
1. A thermal transfer image receiving sheet comprising: a substrate
sheet supporting an image receiving resinous layer for receiving a
transferred image, wherein the image receiving layer is formed by
drying an aqueous coating composition, the aqueous coating
composition comprising (a) at least one water dispersible aliphatic
polyether-polyurethane resin, and at least one water dispersible
aliphatic polyester-polyurethane resin, or (b) at least one water
dispersible aliphatic polyether-polyurethane resin, a silica
dispersion, and an anionic aqueous emulsion of wax; and an aqueous
crosslinking agent.
2. The thermal transfer image receiving sheet of claim 1 wherein
the substrate sheet comprises polyester.
3. The thermal transfer image receiving sheet of claim 2 wherein
the substrate sheet comprises polyethylene terephthalate.
4. The thermal transfer image receiving sheet of claim 1 wherein
the polyether-polyurethane resin comprises the reaction product of
an aliphatic polyisocyanate component and a polyether polyol
component.
5. The thermal transfer image receiving sheet of claim 1 wherein
the polyester-polyurethane resin comprises the reaction product of
an aliphatic polyisocyanate component and a polyester polyol
component.
6. The thermal transfer image receiving sheet of claim 1 wherein
the image receiving resinous layer has a thickness in a range of
from about 1 micrometers to about 50 micrometers.
7. A dye receiving coating composition comprising: an aqueous
dispersion of at least one water dispersible aliphatic
polyether-polyurethane resin; a silica dispersion; and an anionic
aqueous emulsion of wax.
8. The dye receiving coating composition of claim 7 further
comprising a multifunctional crosslinking agent.
9. The dye receiving coating composition of claim 8 wherein the
multifunctional crosslinking agent comprises a polyfunctional
aziridine.
10. The dye receiving coating composition of claim 8 wherein the
coating composition is substantially free of organic solvent.
11. The dye receiving coating composition of claim 7 wherein the
anionic aqueous emulsion of wax comprises
2-diethylaminoethanol.
12. The dye receiving coating composition of claim 7 wherein the
aliphatic polyether polyurethane comprises the reaction product of
an aliphatic polyisocyanate component and a polyether polyol
component.
13. A method of forming a thermal transfer image receiving sheet,
comprising: coating a substrate sheet surface with an aqueous
coating composition, the aqueous coating composition comprising (a)
at least one water dispersible aliphatic polyether-polyurethane
resin, at least one water dispersible aliphatic
polyester-polyurethane resin, and an aqueous crosslinking agent; or
(b) an aqueous dispersion of at least one water dispersible
aliphatic polyether-polyurethane resin, a silica dispersion, and an
anionic aqueous emulsion of wax, and an aqueous crosslinking agent;
and drying the aqueous coating composition, and thereby to form the
thermal transfer image receiving sheet.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of and claims priority to
copending U.S. application Ser. No. 10/797,826, filed Mar. 10,
2004, which claims priority to provisional patent U.S. Application
Ser. No. 60/454,258, filed on Mar. 13, 2003, and to provisional
patent U.S. Application No. 60/454,960, filed on Mar. 14, 2003.
These applications are incorporated by reference herein in their
entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a thermal transfer
image-receiving sheet. More particularly, the present invention
relates to a thermal transfer image-receiving polymeric sheet
capable of recording thereon thermally transferred dye or ink
images in a clear and sharp form.
[0004] 2. Discussion of Related Art
[0005] In thermal transfer recording systems an ink ribbon is
heated through a thermal head or by laser or the like in accordance
with image information. The heating causes thermal melting, thermal
diffusion or sublimation, by which a dye is transferred from the
ink ribbon onto a printing sheet to form an image on the printing
sheet.
[0006] The printing sheet generally is made up of a support film
having a dye receiving layer coated thereon. The dye receiving
layer is a layer that receives a dye or ink transferred thereto
from the ink ribbon by heating and preserves an image formed from
the dye. Typical dye receiving layers for polymeric substrates
comprise at least one dye receptive resin dissolved in an organic
solvent. Examples of such solvent borne resins include polyester,
polycarbonate, polyvinyl chloride, vinyl chloride copolymers such
as vinyl chloride-vinyl acetate copolymer, and thermoplastic resins
such as polyurethane resin, polystyrene, acrylic-styrene (AS)
resin, acrylonitrile-butadiene-styrene (ABS) resin, and the
like.
[0007] It may be desirable to reduce or eliminate the use of
volatile organic solvents in the process for manufacturing
polymeric image receiving sheets. In particular, it may be
desirable to employ an aqueous composition for producing an image
receiving layer on a polyester substrate without compromising image
clarity and durability.
SUMMARY OF THE INVENTION
[0008] According to an aspect of the invention, a printing sheet of
the type that is used in a thermal transfer recording system is
provided. The printing sheet includes a polymeric film support, and
an image receiving layer formed on the film support. The image
receiving layer may be formed from a coating of an aqueous coating
composition. In one embodiment, the aqueous coating composition may
include an aqueous dispersion of an aliphatic
polyester-polyurethane, and an aqueous dispersion of an aliphatic
polyether-polyurethane. In one embodiment, the aqueous coating
composition may include an aqueous dispersion of an aliphatic
polyether-polyurethane resin, a silica dispersion, and an anionic
aqueous emulsion of wax. An aqueous crosslinking agent may be added
to the aqueous coating composition, which may then be dried.
[0009] According to another aspect of the invention, a dye
receiving coating composition is provided. In one embodiment, the
dye receiving coating composition may include an aqueous dispersion
of an aliphatic polyester-polyurethane, and an aqueous dispersion
of an aliphatic polyether-polyurethane. In one embodiment, the dye
receiving coating composition may include an aqueous dispersion of
an aliphatic polyether-polyurethane resin, a silica dispersion, and
an anionic aqueous emulsion of wax. An aqueous crosslinking agent
may be added to the dye receiving coating composition.
[0010] According to yet another aspect of the invention, a method
of preparing a thermal transfer image receiving sheet is provided.
The method provides for coating a substrate sheet surface with the
aqueous coating composition. And, drying the aqueous coating
composition to form the thermal transfer image receiving sheet.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] In the accompanying drawings:
[0012] FIG. 1 is a schematic view illustrating a cross-section of a
thermal transfer image receiving sheet according to the present
invention.
DETAILED DESCRIPTION OF EMBODIMENTS
[0013] The present invention is described in the following
descriptions made with reference to FIG. 1. FIG. 1 is a schematic
view of a cross section of one example of a thermal transfer image
receiving sheet 1 according to the present invention. The thermal
transfer image receiving sheet 1 may include a substrate sheet 2
and a dye receiving layer 3 disposed on one surface of the
substrate sheet 2.
[0014] With reference to the substrate sheet 2, the substrate sheet
2 may be formed from sheet materials selected with reference to
application specific criteria. Such criteria may include, for
example, desired dimensions (height, length and thickness), surface
texture, composition, flexibility, and other physical and economic
attributes or properties. Suitable sheet materials may include, for
example, synthetic papers such as polyolefin type, polystyrene
type; wood free paper; art paper; coat paper; cast coat paper; wall
paper; lining paper; cellulose fiber paper such as paperboard;
various plastic films or sheets such as polyolefin, polyvinyl
chloride, polyethylene terephthalate, polystyrene, polymethacrylate
and polycarbonate.
[0015] In one embodiment, the substrate sheet 2 may be, or may
include, a multilayer polymeric sheet. The multi-layers may be
coextruded, or the multi-layers may be laminated together. In one
embodiment, the substrate sheet 2 includes both some co-extruded
multi-layers and some laminated multi-layers.
[0016] In addition, a white opaque film may be formed by adding a
white pigment, or like fillers, to one or more of the
aforementioned synthetic resins and used as the substrate sheet 2.
In one embodiment, a foamed film is used as the substrate sheet 2.
The foamed film which may be formed by a conventional foaming
operation. In one embodiment, the substrate sheet 2 may be a
laminated body formed by combining a plurality of the
aforementioned single-layered sheets composed of the above listed
materials. Examples of such a laminated body may include a
laminated body of combined cellulose fiber paper with synthetic
paper, and a laminated body of combined cellulose fiber paper with
a plastic film or sheet.
[0017] The thickness of the substrate sheet 2, formed in the manner
as mentioned above, may be determined with reference to application
specific criteria. Such criteria may include the desired end use.
In one embodiment, the sheet thickness is in a range of from about
10 microns or micrometers (.mu.m) to about 300 .mu.m. In one
embodiment, the sheet thickness is in a range of from about 10
micrometers or microns (.mu.m) to about 150 .mu.m. In one
embodiment, the sheet thickness is in a range of from about 150
micrometers or microns (.mu.m) to about 300 .mu.m.
[0018] A primer treatment or a corona discharging treatment may be
used on the substrate sheet 2 to increase a bonding strength
between the substrate sheet 2 and the dye receptor layer 3 to be
formed on a surface of the substrate sheet 2.
[0019] An intermediate layer (not shown) may be provided between
the dye receptor layer 3 and the substrate sheet 2 to impart
preselected properties. Such properties may include an adhesion
property, whiteness or brightness, cushioning property, antistatic
property, shielding property, anti-curling property, and the
like.
[0020] A back surface layer (not shown) may be provided onto a
surface opposite the surface of the substrate sheet 2 to which the
dye receiving layer 3 is formed. The back surface layer may impart
preselected properties to the thermal transfer image receiving
sheet 1. The properties may include, for example, an enhanced
conveying fitness, an enhanced writing property, pollution
resistance, anti-curling property, and the like. If desired, an
antistatic layer (not shown) containing a commercially available
antistatic agent may be provided on the dye receiving layer 2 or
the back surface layer to improve the antistatic property of the
thermal transfer image receiving sheet 1.
[0021] The dye receiving layer 2 may be a coating formed from an
aqueous composition. In one embodiment, the aqueous coating
composition includes at least one water dispersible aliphatic
polyether-polyurethane resin and at least one water dispersible
aliphatic polyester-polyurethane resin. The polyether-polyurethane
resin and the polyester-polyurethane resin may be combined in the
coating composition as separate aqueous dispersions. The
dispersions will typically comprise colloidally dispersed particles
of the polyurethane polymers. In one embodiment, the dye receiving
coating composition has a weight ratio of the
polyether-polyurethane resin to the polyester-polyurethane resin
that is in a range of from about 1:1 to about 2:1, or in a range of
from about 2:1 to about 3:1, based on the resin solids of the
polyether-polyurethane and the polyester-polyurethane.
[0022] In one embodiment, the aqueous coating composition includes,
an aqueous dispersion of an aliphatic polyether-polyurethane resin,
a silica dispersion, and an anionic aqueous emulsion of wax.
[0023] In one embodiment, the polyester-polyurethane polymer is the
reaction product of a predominantly aliphatic polyisocyanate
component and a polyester polyol component. As used herein, the
term "predominantly aliphatic" means that at least 70 weight
percent of the polyisocyanate component is an aliphatic
polyisocyanate, in which all of the isocyanate groups are directly
bonded to aliphatic or cycloaliphatic groups, irrespective of
whether aromatic groups are also present. More preferably, the
amount of aliphatic polyisocyanate is at least 85 weight %, and
most preferably, 100 weight %, of the polyisocyanate component.
Examples of suitable aliphatic polyisocyanates include ethylene
diisocyanate, 1,6-hexamethylene diisocyanate, isophorone
diisocyanate, cyclohexane-1,4-diisocyanate,
4,4'-dicyclohexylmethane diisocyanate, cyclopentylene diisocyanate,
p-tetramethylxylene diisocyanate (p-TMXDI) and its meta isomer
(m-TMXDI), hydrogenated 2,4-toluene diisocyanate, and
1-isocyanto-1-methyl-3(4)-isocyanatomethyl cyclohexane (IMCI).
Mixtures of aliphatic polyisocyanates can be used.
[0024] Polyester polyols that may be used in the polyester polyol
component include hydroxyl-terminated reaction products of
polyhydric alcohols such as ethylene glycol, propylene glycol,
diethylene glycol, neopentyl glycol, 1,4-butanediol,
1,6-hexanediol, furan dimethanol, cyclohexane dimethanol, glycerol,
trimethylolpropane or pentaerythritol, or mixtures thereof. Also
included are polycarboxylic acids, especially dicarboxylic acids,
and ester-forming derivatives thereof. Examples include succinic,
glutaric and adipic acids or their methyl esters, phthalic
anhydride and dimethyl terephthalate. Polyesters obtained by the
polymerisation of lactones, for example caprolactone, in
conjunction with a polyol may also be used. Commercially available
polyester-polyurethanes useful in the present invention include
those sold under the trade names AVALURE UR-425, AVALURE UR-430,
AVALURE UR-405 and AVALURE UR-410 by Goodrich Corporation
(Charlotte, N.C.), and NEOREZ R-989 by NeoResins (Waalwijk, The
Netherlands).
[0025] In one embodiment, the polyether-polyurethane polymer is the
reaction product of a predominantly aliphatic polyisocyanate
component and a polyether polyol component. Useful aliphatic
polyisocyanates are described above. Suitable polyether polyols
include products obtained by the polymerization of a cyclic oxide
or by the addition of one or more such oxides to polyfunctional
initiators. Such polymerized cyclic oxides include, for example,
ethylene oxide, propylene oxide and tetrahydrofuran. Such
polyfunctional initiators having oxides added include, for example,
water, ethylene glycol, propylene glycol, diethylene glycol,
cyclohexane dimethanol, glycerol, trimethylopropane,
pentaerythritol and Bisphenols (such as A and F).
[0026] Suitable polyesters include polyoxypropylene diols and
triols, poly (oxyethylene-oxypropylene) diols and triols obtained
by the simultaneous or sequential addition of ethylene and
propylene oxides to appropriate initiators and polytetramethylene
ether glycols obtained by the polymerisation of tetrahydrofuran.
Commercially available polyether-polyurethanes useful in the
present invention include those sold under the trade names SANCURE
878, AVALURE UR-450 and SANCURE 861 by Goodrich Corporation
(Charlotte, N.C.), and NEOREZ R-551 by NeoResins (Waalwijk, The
Netherlands).
[0027] The dye receiving layer 3 may include a water dispersible
crosslinker. Suitable water-dispersible polyfunctional chemically
activatable crosslinking agents are commercially available. These
crosslinking agents include dispersible formulations of
polyfunctional aziridines, isocyanates, melamine resins, epoxies,
oxazolines, carbodiimides and other polyfunctional crosslinkers. In
one embodiment, the crosslinking agents are added at an amount in a
range of from about 0.1 parts to about 10 parts based on 100 parts
total solids. In one embodiment, the crosslinking agents are added
at an amount in a range of from about 0.2 parts to about 5 parts
based on 100 parts total solids. Adding crosslinking agents to the
polyurethane dispersion composition may form an interpenetrating or
interconnected network having crosslinked matrixes is formed which
link the blended polymers with covalent and/or non-covalent
linkages.
[0028] The dye receiving layer 3, to be formed as mentioned above,
may have a predetermined thickness based on factors such as
viscosity; application type, amount and method; desired end use;
and the like. In one embodiment, the thickness may be in a range of
about 1 .mu.m to about 50 .mu.m. In one embodiment, the thickness
may be in a range of from about 1 .mu.m to about 25 .mu.m, and in
one embodiment in a range of from about 25 um to about 50 um.
[0029] The image receiving sheet 1 may be applied to applications
where thermal transfer printing can be conducted. Suitable
applications include image receiving sheets in a flat sheet or roll
form, cards and sheets for preparing transparent originals.
Selection of the parameters defining the substrate sheet 2 may aid
in tailoring the image receiving sheet 1 to the desired
application.
EXAMPLES
[0030] The following examples are intended only to illustrate
methods and embodiments in accordance with the invention, and as
such should not be construed as imposing limitations upon the
claims. Unless specified otherwise, all ingredients are
commercially available from such common chemical suppliers as Sigma
Aldrich, Inc. (St. Louis, Mo.) and/or Fisher Scientific
International, Inc. (Hanover Park, Ill.).
Example 1
[0031] A coating composition comprising the ingredients listed in
Table 1 is prepared as follows. Equal amounts by weight of water
and of the blend of polyurethane dispersions were added together,
i.e., 100 parts water to 100 parts dispersion.
[0032] The coating composition was then coated onto a semi-clear,
biaxially oriented polyethylene terephthalate (PET) substrate web.
The web may have a thickness of about 25 micrometers. The coating
was dried at a temperature of 90 degrees Celsius and a line speed
of 120 meters/minute to form an image receiving layer. The dry coat
weight of the image receiving layer was in a range of from about
0.8 g/m.sup.2 to about 1 g/m.sup.2.
[0033] The coating composition of Example 1 was also coated onto a
matte chrome, biaxially oriented PET substrate having a thickness
of 50 microns, and onto a white, biaxially oriented PET substrate
having a thickness of 50 microns. TABLE-US-00001 TABLE 1 Ingredient
list for Example 1. Ingredient % wt. Polyurethane dispersion 70
(NEOREZ R-551: aliphatic polyether urethane dispersion, 35.5%
solids) Polyurethane dispersion 29.9 (NEOREZ R-989: aliphatic
polyester urethane dispersion, 40% solids) Crosslinker 0.1
(Crosslinker CX-100: polyfunctional aziridine crosslinker)
Example 2
[0034] A coating composition comprising the ingredients listed in
Table 2 is prepared as follows. The ingredients are mixed until
substantially uniform and coated onto a substrate web in
substantially the same manner as in Example 1. The coated substrate
web of PET is suitable for laser printing, and with UV curable
inks. TABLE-US-00002 TABLE 2 Ingredient list for Example 2.
Ingredient % wt. Polyurethane dispersion 48.4 (NEOREZ R-563:
aliphatic polyether urethane dispersion, 35.5% solids) Silica
dispersion 0.5 (Polymer Product-FP 44) Anionic aqueous emulsion of
combined waxes 1.0 (AQUACER 537: amino alcohol) Crosslinker 0.1
(Crosslinker CX-100: polyfunctional aziridine crosslinker) Water
50.0
[0035] AQUACER 537, which is commercially available from Byk-Cera,
which is a subsidiary of Byk-Chemie a division of ALTANA AG (Bad
Homburg, Germany) is 2-diethylaminoethanol.
[0036] While the invention has been explained in relation to
embodiments, it is to be understood that various modifications
thereof will become apparent to those skilled in the art upon
reading the specification. Therefore, it is to be understood that
the invention disclosed herein is intended to cover such
modifications as fall within the scope of the appended claims, and
to cover insubstantial variations thereof.
* * * * *