Thermal dye transfer receiving element with polyester/polycarbonate blended dye image-receiving layer

A dye-receiving element for thermal dye transfer includes a support having on one side thereof a dye image-receiving layer. Receiving elements of the invention are characterized in that the dye image-receiving layer comprises a miscible blend of an unmodified bisphenol-A polycarbonate having a number molecular weight of at least about 25,000 and a polyester comprising recurring dibasic acid derived units and diol derived units, at least 50 mole % of the dibasic acid derived units comprising dicarboxylic acid derived units containing an alicyclic ring within two carbon atoms of each carboxyl group of the corresponding dicarboxylic acid, and at least 30 mole % of the diol derived units containing an aromatic ring not immediately adjacent to each hydroxyl group of the corresponding diol or an alicyclic ring.

This invention relates to dye-receiving elements used in thermal dye 
transfer, and more particularly to polymeric dye image-receiving layers 
for such elements. 
In recent years, thermal transfer systems have been developed to obtain 
prints from pictures which have been generated electronically from a color 
video camera. According to one way of obtaining such prints, an electronic 
picture is first subjected to color separation by color filters. The 
respective color-separated images are then converted into electrical 
signals. These signals are then operated on to produce cyan, magenta and 
yellow electrical signals. These signals are then transmitted to a thermal 
printer. To obtain the print, a cyan, magenta or yellow dye-donor element 
is placed face-to-face with a dye-receiving element. The two are then 
inserted between a thermal printing head and a platen roller. A line-type 
thermal printing head is used to apply heat from the back of the dye-donor 
sheet. The thermal printing head has many heating elements and is heated 
up sequentially in response to one of the cyan, magenta or yellow signals, 
and the process is then repeated for the other two colors. A color hard 
copy is thus obtained which corresponds to the original picture viewed on 
a screen. Further details of this process and an apparatus for carrying it 
out are contained in U.S. Pat. No. 4,621,271 by Brownstein entitled 
"Apparatus and Method For Controlling A Thermal Printer Apparatus," issued 
Nov. 4, 1986, the disclosure of which is hereby incorporated by reference. 
Dye receiving elements used in thermal dye transfer generally include a 
support (transparent or reflective) bearing on one side thereof a dye 
image-receiving layer, and optionally additional layers. The dye 
image-receiving layer conventionally comprises a polymeric material chosen 
from a wide assortment of compositions for its compatibility and 
receptivity for the dyes to be transferred from the dye donor element. Dye 
must migrate rapidly in the layer during the dye transfer step and become 
immobile and stable in the viewing environment. Care must be taken to 
provide a receiver layer which does not stick to the hot donor and where 
the dye moves from the surface and into the bulk of the receiver. An 
overcoat layer can be used to improve the performance of the receiver by 
specifically addressing these latter problems. An additional step, 
referred to as fusing, may be used to drive the dye deeper into the 
receiver. 
Polycarbonates (the term "polycarbonate" as used herein means a polyester 
of carbonic acid and a diol or diphenol) and polyesters have been 
suggested for use in image-receiving layers. Polycarbonates have been 
found to be desirable image-receiving layer polymers because of their 
effective dye compatibility and receptivity. As set forth in U.S. Pat. No. 
4,695,286, bisphenol-A polycarbonates of number average molecular weights 
of at least about 25,000 have been found to be especially desirable in 
that they also minimize surface deformation which may occur during thermal 
printing. These polycarbonates, however, do not always achieve dye 
transfer densities as high as may be desired, and their stability to light 
fading may be inadequate. U.S. Pat. No. 4,927,803 discloses that modified 
bisphenol-A polycarbonates obtained by co-polymerizing bisphenol-A units 
with linear aliphatic diols may provide increased stability to light 
fading compared to ummodified polycarbonates. Such modified 
polycarbonates, however, are relatively expensive to manufacture compared 
to the readily available bisphenol-A polycarbonates, and they are 
generally made in solution from hazardous materials (e.g. phosgene and 
chloroformates) and isolated by precipitation into another solvent. The 
recovery and disposal of solvents coupled with the dangers of handling 
phosgene make the preparation of specialty polycarbonates a high cost 
operation. 
Polyesters, on the other hand, can be readily synthesized and processed by 
melt condensation using no solvents and relatively innocuous chemical 
starting materials. Polyesters formed from aromatic diesters (such as 
disclosed in U.S. Pat. No. 4,897,377) generally have good dye up-take 
properties when used for thermal dye transfer; however, they exhibit 
severe fade when the dye images are subjected to high intensity daylight 
illumination. Polyesters formed from alicyclic diesters are disclosed in 
copending U.S. Ser. No. 07/801,223 of Daly, the disclosure of which is 
incorporated by reference. These alicyclic polyesters also generally have 
good dye up-take properties, but their manufacture requires the use of 
specialty monomers which add to the cost of the receiver element. 
Polyesters formed from aliphatic diesters generally have relatively low 
glass transition temperatures, which frequently results in 
receiver-to-donor sticking at temperatures commonly used for thermal dye 
transfer. When the donor and receiver are pulled apart after imaging, one 
or the other fails and tears and the resulting images are unacceptable. 
Polymers may be blended for use in the dye-receiving layer in order to 
obtain the advantages of the individual polymers and optimize the combined 
effects. For example, relatively inexpensive unmodified bisphenol-A 
polycarbonates of the type described in U.S. Pat. No. 4,695,286 may be 
blended with the modified polycarbonates of the type described in U.S. 
Pat. No. 4,927,803 in order to obtain a receiving layer of intermediate 
cost having both improved resistance to surface deformation which may 
occur during thermal printing and to light fading which may occur after 
printing. A problem with such polymer blends, however, results if the 
polymers are not completely miscible with each other, as such blends may 
exhibit a certain amount of haze. While haze is generally undesirable, it 
is especially detrimental for transparency receivers. Blends which are not 
completely compatible may also result in variable dye uptake, poorer image 
stability, and variable sticking to dye donors. 
Fingerprint resistance is another desirable property for image-receiving 
layer polymers, since fingerprints present one potential image stability 
problem with thermal dye transfer images. Contaminants from fingerprints 
may attack the dyes and, therefore, degrade the image. The result is often 
a dye density loss due to crystallization. 
Retransfer is another potential image stability problem with thermal dye 
transfer images. The receiver must act as a medium for dye diffusion at 
elevated temperatures, yet the transferred image dye must not be allowed 
to migrate from the final print. Retransfer is observed when another 
surface comes into contact with a final print. Such surfaces may include 
paper, plastics, binders, backside of (stacked) prints, and some album 
materials. 
Accordingly, it would be highly desirable to provide a receiver element for 
thermal dye transfer processes with a dye image receiving layer comprising 
a polymer blend having excellent dye uptake and image dye stability, and 
which is essentially free from haze. It would be further desirable to 
provide such a receiver having improved fingerprint resistance and 
retransfer resistance, and which can be effectively printed in a thermal 
printer with significantly reduced thermal head pressures and printing 
line times. 
These and other objects are achieved in accordance with this invention 
which comprises a dye-receiving element for thermal dye transfer 
comprising a support having on one side thereof a dye image-receiving 
layer, wherein the dye image-receiving layer comprises a miscible blend of 
an unmodified bisphenol-A polycarbonate having a number molecular weight 
of at least about 25,000 and a polyester comprising recurring dibasic acid 
derived units and diol derived units, at least 50 mole % of the dibasic 
acid derived units comprising dicarboxylic acid derived units containing 
an alicyclic ring within two carbon atoms of each carboxyl group of the 
corresponding dicarboxylic acid, and at least 30 mole % of the diol 
derived units containing an aromatic ring not immediately adjacent to each 
hydroxyl group of the corresponding diol or an alicyclic ring. 
Surprisingly, these alicyclic polyesters were found to be compatible with 
high molecular weight polycarbonates. 
Examples of unmodified bisphenol-A polycarbonates having a number molecular 
weight of at least about 25,000 include those disclosed in U.S. Pat. No. 
4,695,286. Specific examples include Makrolon 5700 (Bayer AG) and LEXAN 
141 (General Electric Co.) polycarbonates. 
##STR1## 
The polyester polymers used in the dye-receiving elements of the invention 
are condensation type polyesters based upon recurring units derived from 
alicyclic dibasic acids (Q) and diols (L) wherein (Q) represents one or 
more alicyclic ring containing dicarboxylic acid units with each carboxyl 
group within two carbon atoms of (preferably immediately adjacent to) the 
alicyclic ring and (L) represents one or more diol units each containing 
at least one aromatic ring not immediately adjacent to (preferably from 1 
to about 4 carbon atoms away from) each hydroxyl group or an alicyclic 
ring which may be adjacent to the hydroxyl groups. For the purposes of 
this invention, the terms "dibasic acid derived units" and "dicarboxylic 
acid derived units" are intended to define units derived not only from 
carboxylic acids themselves, but also from equivalents thereof such as 
acid chlorides, acid anhydrides and esters, as in each case the same 
recurring units are obtained in the resulting polymer. Each alicyclic ring 
of the corresponding dibasic acids may also be optionally substituted, 
e.g. with one or more C.sub.1 to C.sub.4 alkyl groups. Each of the diols 
may also optionally be substituted on the aromatic or alicyclic ring, e.g. 
by C.sub.1 to C.sub.6 alkyl, alkoxy, or halogen. 
In a preferred embodiment of the invention, the alicyclic rings of the 
dicarboxylic acid derived units and diol derived units contain from 4 to 
10 ring carbon atoms. In a particularly preferred embodiment, the 
alicyclic rings contain 6 ring carbon atoms. 
The alicyclic dicarboxylic acid units, (Q), are represented by structures 
such as: 
##STR2## 
The diols, (L), are represented by structures such as: 
##STR3## 
Optionally other groups, R and M, may be copolymerized to produce 
structures such as: 
##STR4## 
wherein q+r=l+m=100 mole % and q is at least 50 mole percent and l is at 
least 30 mole percent. 
Diesters R and diols M may be added, e.g., to precisely adjust the 
polymer's Tg, solubility, adhesion, etc. Additional diester comonomers 
could have the cyclic structure of Q or be linear aliphatic units. The 
additional diol monomers may have aliphatic or aromatic structure but are 
not phenolic. 
Suitable groups for R include dibasic aliphatic acids such as: 
R1: HO.sub.2 C(CH.sub.2).sub.2 CO.sub.2 H 
R2: HO.sub.2 C(CH.sub.2).sub.4 CO.sub.2 H 
R3: HO.sub.2 C(CH.sub.2).sub.7 CO.sub.2 H 
R4: HO.sub.2 C(CH.sub.2).sub.10 CO.sub.2 H 
Suitable groups for M include diols such as: 
M1: HOCH.sub.2 CH.sub.2 OH 
M2: HO(CH.sub.2).sub.4 OH 
M3: HO(CH.sub.2).sub.9 OH 
M4: HOCH.sub.2 C(CH.sub.3).sub.2 CH.sub.2 OH 
M5: (HOCH.sub.2 CH.sub.2).sub.2 O 
M6: HO(CH.sub.2 CH.sub.2 O).sub.n H (where n=2 to 50) 
Among the necessary features of the polyesters for the blends of the 
invention is that they do not contain an aromatic diester such as 
terephthalate, and that they be compatible with the polycarbonate at the 
composition mixtures of interest. The polyester preferably has a Tg of 
from about 40.degree. to about 100.degree. C., and the polycarbonate a Tg 
of from about 100.degree. to about 200.degree. C. The polyester preferably 
has a lower Tg than the polycarbonate, and acts as a polymeric plasticizer 
for the polycarbonate. The Tg of the final polyester/polycarbonate blend 
is preferably between 40.degree. C. and 100.degree. C. Higher Tg polyester 
and polycarbonate polymers may be useful with added plasticizer. 
In a preferred embodiment of the invention, the polyesters have a number 
molecular weight of from about 5,000 to about 250,000 more preferably from 
10,000 to 100,000. 
In a further preferred embodiment of the invention, the unmodified 
bisphenol-A polycarbonate and the polyester polymers are blended at a 
weight ratio to produce the desired Tg of the final blend and to minimize 
cost. Convienently, the polycarbonate and polyester polymers may be 
blended at a weight ratio of from about 75:25 to 25:75, more preferably 
from about 60:40 to about 40:60. 
The following polyester polymers E-1 through E-17 (comprised of recurring 
units of the illustrated monomers) are examples of polyester polymers 
usable in the receiving layer polymer blends of the invention. 
E-1 to E-5: Polymers which are preferred and considered to be derived from 
1,4-cyclohexanedicarboxylic acid, ethylene glycol, and 
4,4'-bis(2-hydroxyethyl) bisphenol-A. 
##STR5## 
E-6: A polymer considered to be derived from 1,4-cyclohexanedicarboxylic 
acid and 4,4'-bis(2-hydroxyethyl) bisphenol-A 
##STR6## 
E-7 and E-8: Polymers considered to be derived from 
1,4-cyclohexanedicarboxylic acid, ethylene glycol and 
1,4-cyclohexanedimethanol 
##STR7## 
E-9: A polymer considered to be derived from 1,4-cyclohexanedicarboxylic 
acid and 1,4-cyclohexane dimethanol 
##STR8## 
E-10 and E-11: Polymers considered to be derived from 
1,4-cyclohexanedicarboxylic acid, 4,4'-bis(hydroxyethyl) bisphenol-A, and 
4,4'-(2-norbornylidene)-bis(2-hydroxyethyl)bisphenol 
##STR9## 
E-12 and E-13: Polymers considered to be derived from 
1,4-cyclohexanedicarboxylic acid, ethylene glycol, and 
4,4'-(2-norbornylidene)-bis(2-hydroxyethyl)bisphenol 
##STR10## 
E-14: A polymer considered to be derived from 1,4-cyclohexanedicarboxylic 
acid, ethylene glycol, and 
4,4'-(hexahydro-4,7-methanoindene-5-ylidene)-bis(2-hydroxyethyl)bisphenol 
##STR11## 
E-15: A polymer considered to be derived from 1,4-cyclohexanedicarboxylic 
acid, azelaic acid, ethylene glycol and 
4,4'-bis(2-hydroxyethyl)bisphenol-A 
##STR12## 
E-16 and E-17: A polymer considered to be derived from 
1,3-cyclohexanedicarboxylic acid, ethylene glycol, and 
4,4'-bis(2-hydroxyethyl)bisphenol-A 
##STR13## 
Other polyester polymers usable in the blends of the invention include E-18 
to E-31 listed below: 
______________________________________ 
Alicyclic Alternate Alternate 
Diacid Diacid Glycol Glycol 
Polymer 
Mole % O Mole % R Mole % L 
Mole % M 
______________________________________ 
E-18 100% Q1 -- 30% L2 70% M1 
E-19 100% Q1 -- 50% L9 48% M1 
2% M6 (n.about.35) 
E-20 100% Q1 -- 50% L13 50% M1 
E-21 100% Q1 -- 50% L21 50% M1 
E-22 100% Q2 -- 70% L11 30% M1 
E-23 100% Q2 -- 100% L16 
-- 
E-24 70% Q2 30% R2 50% L21, 
-- 
50% L11 
E-25 50% Q1, -- 50% L1 50% M1 
50% Q2 
E-26 50% Q1, -- 100% L5 -- 
50% Q2 
E-27 100% Q4 -- 100% L10 
-- 
E-28 70% Q4 30% R1 50% L1 50% M1 
E-29 100% Q6 -- 100% L14 
-- 
E-30 100% Q7 -- 50% L14 50% M4 
E-31 100% Q8 -- 30% L6 70% M1 
______________________________________ 
The support for the dye-receiving element of the invention may be 
transparent or reflective, and may comprise a polymeric, a synthetic 
paper, or a cellulosic paper support, or laminates thereof. Examples of 
transparent supports include films of poly(ether sulfones), polyimides, 
cellulose esters such as cellulose acetate, poly(vinyl 
alcohol-co-acetals), and poly(ethylene terephthalate). The support may be 
employed at any desired thickness, usually from about 10 .mu.m to 1000 
.mu.m. Additional polymeric layers may be present between the support and 
the dye image-receiving layer. For example, there may be employed a 
polyolefin such as polyethylene or polypropylene. White pigments such as 
titanium dioxide, zinc oxide, etc., may be added to the polymeric layer to 
provide reflectivity. In addition, a subbing layer may be used over this 
polymeric layer in order to improve adhesion to the dye image-receiving 
layer. Such subbing layers are disclosed in U.S. Pat. Nos. 4,748,150, 
4,965,238, 4,965,239, and 4,965,241, the disclosures of which are 
incorporated by reference. The receiver element may also include a backing 
layer such as those disclosed in U.S. Pat. Nos. 5,011,814 and 5,096,875, 
the disclosures of which are incorporated by reference. 
The dye image-receiving layer may be present in any amount which is 
effective for its intended purpose. In general, good results have been 
obtained at a receiver layer concentration of from about 0.5 to about 10 
g/m.sup.2. 
Resistance to sticking during thermal printing may be enhanced by the 
addition of release agents to the dye receiving layer or to an overcoat 
layer, such as silicone based compounds, as is conventional in the art. 
Dye-donor elements that are used with the dye-receiving element of the 
invention conventionally comprise a support having thereon a dye 
containing layer. Any dye can be used in the dye-donor employed in the 
invention provided it is transferable to the dye-receiving layer by the 
action of heat. Especially good results have been obtained with sublimable 
dyes. Dye donors applicable for use in the present invention are 
described, e.g., in U.S. Pat. Nos. 4,916,112, 4,927,803 and 5,023,228, the 
disclosures of which are incorporated by reference. 
As noted above, dye-donor elements are used to form a dye transfer image. 
Such a process comprises imagewise-heating a dye-donor element and 
transferring a dye image to a dye-receiving element as described above to 
form the dye transfer image. 
In a preferred embodiment of the invention, a dye-donor element is employed 
which comprises a poly(ethylene terephthalate) support coated with 
sequential repeating areas of cyan, magenta and yellow dye, and the dye 
transfer steps are sequentially performed for each color to obtain a 
three-color dye transfer image. Of course, when the process is only 
performed for a single color, then a monochrome dye transfer image is 
obtained. 
Thermal printing heads which can be used to transfer dye from dye-donor 
elements to the receiving elements of the invention are available 
commercially. There can be employed, for example, a Fujitsu Thermal Head 
(FTP-040 MCS001), a TDK Thermal Head F415 HH7-1089 or a Rohm Thermal Head 
KE 2OO8-F3. Alternatively, other known sources of energy for thermal dye 
transfer may be used, such as lasers as described in, for example, GB No. 
2,083,726A. 
A thermal dye transfer assemblage of the invention comprises (a) a 
dye-donor element, and (b) a dye-receiving element as described above, the 
dye-receiving element being in a superposed relationship with the 
dye-donor element so that the dye layer of the donor element is in contact 
with the dye image-receiving layer of the receiving element. 
When a three-color image is to be obtained, the above assemblage is formed 
on three occasions during the time when heat is applied by the thermal 
printing head. After the first dye is transferred, the elements are peeled 
apart. A second dye-donor element (or another area of the donor element 
with a different dye area) is then brought in register with the 
dye-receiving element and the process repeated. The third color is 
obtained in the same manner. 
The following examples are provided to further illustrate the invention. 
The synthesis example is representative, and other polyesters may be 
prepared analogously or by other methods know in the art. 
Preparation of Polyester E-9: poly(methylene 1,4-cyclohexane methylene 
carbonyl 1,4-cyclohexane carbonyl) 
The following quantities of reactants were charged to a reactor purged with 
nitrogen: 8.11 kg (44.1 mol) of dimethyl cis/trans 
1,4-cyclohexanedicarboxylate; 6.72 kg (50.7 mol) of trans 
1,4-cyclohexanedimethanol; and 45.4 gms of a 2.6 wt % of tetraisopropyl 
orthotitanate. Under a nitrogen purge, the reactor was heated to 
220.degree. C. and maintained there for one hour. The temperature was then 
raised to 240.degree. C. and maintained for an additional hour. At this 
point, traps were drained and drainings were recorded. The temperature was 
increased to 260.degree. C. and held there for 30 minutes. Traps were 
again drained and drainings recorded. The temperature was raised to 
290.degree. C., the pressure was reduced to 53 Pa. The reactor was then 
placed under 667 Pa vacuum with reactor temperature at 290.degree. C. and 
left there for three hours. Once buildup was complete, the polymer was 
extruded from the reactor into water using an extruding die. The resulting 
polymer was dried in a vacuum oven at 80.degree. C. under a nitrogen purge 
for four hours. The polymer was ground yielding 7.94 kg of material. 
Tg=66.degree. C.; Tm=213.45.degree. C.; IV=0.843.

RECEIVING ELEMENT EXAMPLE 1 
Dye-receiving element DR-1 used for haze measurements was prepared by 
coating the following layers in the order recited on a 175 .mu.m thick 
poly(ethylene terephthalate) support: 
(1) Subbing layer of poly(acrylonitrile-co-vinylidene chloride-co-acrylic 
acid) (15:79:6 wt. ratio) (0.11 g/m.sup.2) coated from distilled water, 
and 
(2) a dye receiving layer composed of a blend of Bayer AG Makrolon 5700 
unmodified bisphenol A polycarbonate (1.61 g/m.sup.2)(Tg=157.degree. C.) 
and polyester E-9 (1.61 g/m.sup.2) containing diphenyl phthalate (0.32 
g/m.sup.2) and dibutyl phthalate (0.32 g/m.sup.2) as plasticizers and 
Fluorad FC-431 (surfactant of 3M Co.) (0.016 g/m.sup.2) coated from 
dichloromethane. 
Comparison receivers C-1 and C-2 were prepared by coating the following dye 
receiving layers in place of the invention dye receiving layer: 
C-1: Receiving layer composed of a blend of Bayer AG Makrolon 5700 
unmodified bisphenol A polycarbonate (1.61 g/m.sup.2) and a random 50:50 
mol % copolymer of bisphenol-A carbonate with diethylene glycol (the 
modified polycarbonate illustrated below) (1.61 g/m.sup.2) and Fluorad 
FC-431 (3M Co.) (0.016 g/:m.sup.2) coated from dichloromethane. 
##STR14## 
C-2: Receiving layer composed of a blend of Bayer AG Makrolon 5700 
unmodified bisphenol A polycarbonate (1.61 g/m.sup.2) and the modified 
polycarbonate shown above (1.61 g/m.sup.2) containing diphenyl phthalate 
(0.32 g/m.sup.2) and dibutyl phthalate (0.32 g/m.sup.2) as plasticizers 
and Fluorad FC-431 (3M Co.) (0.016 g/m.sup.2) coated from dichloromethane. 
After drying, the degree of haze for each receiver was determined according 
to the standard ASTM test procedure (Test Method D1003). The results from 
the haze measurements are summarized in Table I below. 
TABLE I 
______________________________________ 
RECEIVER % HAZE 
______________________________________ 
Uncoated 0.5 
PET Support 
DR-1 0.4 
C-1 6.6 
C-2 5.9 
______________________________________ 
RECEIVING ELEMENT EXAMPLE 2 
Dye-receiving element DR-2 used for evaluation as receiving layers for 
thermal imaging was prepared by coating the following layers in the order 
recited on a titanium dioxide-pigmented polyethylene-overcoated paper 
stock: 
(1) Subbing layer of poly(acrylonitrile-co-vinylidene chloride-co-acrylic 
acid) (15:78:7 wt. ratio) (0.11 g/m.sup.2) coated from 2-butanone, and 
(2) Dye receiving layer composed of a blend of Bayer AG Makrolon 5700 
unmodified bisphenol A polycarbonate (1.61 g/m.sup.2) and polyester E-9 
(1.61 g/m.sup.2) and Fluorad FC-431 (3M Co.) (0.016 g/m.sup.2) coated from 
dichloromethane. 
Dye-receiving element DR-3 and comparison dye-receiving elements C-3, C-4 
and C-5 were prepared by coating the following dye-receiving layers in 
place of the DR-2 receiving layer: 
DR-3 receiving layer composed of a blend of Bayer AG Makrolon 5700 
unmodified bisphenol A polycarbonate (1.61 g/m.sup.2) and polyester E-9 
(1.61 g/m.sup.2) containing diphenyl phthalate (0.32 g/m.sup.2) and 
dibutyl phthalate (0.32 g/m.sup.2) as plasticizers and Fluorad FC-431 (3M 
Co.) (0.016 g/m.sup.2) coated from dichloromethane. 
C-3: Receiving layer composed of Bayer AG Makrolon 5700 unmodified 
bisphenol A polycarbonate (3.23 g/m.sup.2) and Fluorad FC-431 (3M Co.) 
(0.016 g/m.sup.2) coated from dichloromethane. 
C-4: Receiving layer composed of a blend of Bayer AG Makrolon 5700 
unmodified bisphenol A polycarbonate (1.61 g/m.sup.2) and the modified 
polycarbonate shown in Example 1 above (1.61 g/m.sup.2) and Fluorad FC-431 
(3M Co.) (0.016 g/m.sup.2) coated from dichloromethane. 
C-5: Receiving layer composed of a blend of Bayer AG Makrolon 5700 
unmodified bisphenol A polycarbonate (1.61 g/m.sup.2) and the modified 
polycarbonate shown in Example 1 above (1.61 g/m.sup.2) containing 
diphenyl phthalate (0.32 g/m.sup.2) and dibutyl phthalate (0.32 g/m.sup.2) 
as plasticizers and Fluorad FC-431 (3M Co.) (0.016 g/m.sup.2) coated from 
dichloromethane. 
All coatings were dried at ambient room conditions for at least 16 hours 
prior to evaluation. 
A dye donor element of sequential areas of cyan, magenta and yellow dye was 
prepared by coating the following layers in order on a 6 .mu.m 
poly(ethylene terephthalate) support: 
(1) Subbing layer of Tyzor TBT (titanium tetra-n-butoxide) (duPont Co.) 
(0.12 g/m.sup.2) from a n-propyl acetate and 1-butanol solvent mixture. 
(2) Dye-layer containing Cyan Dye 1 (0.42 g/m2) illustrated below, a 
mixture of Magenta Dye 1 (0.11 g/m2) and Magenta Dye 2 (0.12 g/m2) 
illustrated below, or Yellow Dye 1 illustrated below (0.20 g/m.sup.2) and 
S-363N1 (a micronized blend of polyethylene, polypropylene and oxidized 
polyethylene particles) (Shamrock Technologies, Inc.) (0.02 g/m.sup.2) in 
a cellulose acetate propionate binder (2.5% acetyl, 45% propionyl) 
(0.15-0.70 g/m.sup.2) from a toluene, methanol, and cyclopentanone solvent 
mixture. 
On the reverse side of the support was coated: 
(1) Subbing layer of Tyzor TBT (0.12 g/m.sup.2) from a n-propyl acetate and 
1-butanol solvent mixture. 
(2) Slipping layer of Emralon 329 (a dry film lubricant of 
poly(tetrafluoroethylene) particles in a cellulose nitrate resin binder) 
(Acheson Colloids Corp.) (0.54 g/m.sup.2), p-toluene sulfonic acid (0.0001 
g/m.sup.2), BYK-320 (copolymer of a polyalkylene oxide and a methyl 
alkylsiloxane) (BYK Chemie, USA) (0.006 g/m.sup.2), and Shamrock 
Technologies Inc. S-232 (micronized blend of polyethylene and carnauba wax 
particles) (0.02 g/m.sup.2), coated from a n-propyl acetate, toluene, 
isopropyl alcohol and n-butyl alcohol solvent mixture. 
##STR15## 
The dye side of the dye-donor element approximately 10 cm.times.13 cm in 
area was placed in contact with the polymeric receiving layer side of the 
dye-receiver element of the same area. The assemblage was fastened to the 
top of a motor-driven 56 mm diameter rubber roller and a TDK Thermal Head 
L-231, thermostated at 22.degree. C., was pressed with a spring at a force 
of 36 Newtons (3.2 kg) against the dye-donor element side of the 
assemblage pushing it against the rubber roller. 
The imaging electronics were activated and the assemblage was drawn between 
the printing head and roller at 7.0 mm/sec. Coincidentally, the resistive 
elements in the thermal print head were pulsed in a determined pattern for 
29 .mu.sec/pulse at 129 .mu.sec intervals during the 33 msec/dot printing 
time to create an image. When desired, a stepped density image was 
generated by incrementally increasing the number of pulses/dot from 0 to 
255. The voltage supplied to the print head was approximately 24.5 volts, 
resulting in an instantaneous peak power of 1.27 watts/dot and a maximum 
total energy of 9.39 mjoules/dot. 
Individual cyan, magenta and yellow images were obtained by printing from 
three dye-donor patches. When properly registered a full color image was 
formed. The Status A red, green, and blue reflection density of the 
stepped density image at maximum density, Dmax, were read and recorded. 
The step of each dye image nearest a density of 1.0 was then subjected to 
exposure for 1 week, 50 kLux, 5400.degree. K., approximately 25% RH. The 
Status A red, green and blue reflection densities were compared before and 
after fade and the percent density loss was calculated. The results are 
presented in Table II below. 
TABLE II 
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DYE UPTAKE STATUS A % FADE 
(Dmax) (Initial O.D. = 1.0) 
RECEIVER Red Green Blue Red Green Blue 
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DR-2 2.42 2.56 2.33 18 34 24 
DR-3 2.89 2.74 2.51 20 26 14 
C-3 2.14 2.36 2.19 25 62 52 
C-4 2.04 2.04 1.96 18 25 15 
C-5 2.44 2.26 2.23 20 20 15 
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A receiver layer produced by solvent coating a mixture of an alicyclic 
polyester and polycarbonate was not hazy and gave higher dye uptake and 
comparable dye fade relative to the polycarbonate/polycarbonate blend. The 
advantages of replacing the modified polycarbonate in the blended receiver 
with the alicyclic polyester include elimination of haze in coatings, 
reduction of manufacturing costs, and reduction of environmental hazards. 
The compatible alicyclic polyester and polycarbonate blends have also been 
found to help minimize retransfer of dye from an imaged receiver and 
provide improved fingerprint resistance compared to incompatible polymer 
blends. 
The invention has been described in detail with particular reference to 
preferred embodiments thereof, but it will be understood that variations 
and modifications can be effected within the spirit and scope of the 
invention.