Dye image receiving material

An image receiving material suitable for image production by dye diffusion transfer processing controlled by the development of (an) image-wise exposed silver halide emulsion layer(s), wherein said image receiving material comprises a supported image receiving layer free from gelatin and containing (1) a cationic polymeric mordant, and (2) colloidal silica applied from an aqueous acidic colloidal sol having a pH of not more than 4, and containing hydrated silica in combination with a smaller amount of colloidal alumina, the amount of said colloidal material to said mordant in the image-receiving layer being in a weight ratio range from 1/5 to 1/2, and silica (SiO.sub.2) being present at a coverage of at least 0.5 g per m2.

DESCRIPTION 
The present invention relates to a material containing an image receiving 
layer suitable for carrying out a dye diffusion transfer processing 
controlled by the development of a photo-exposed silver halide emulsion 
layer. 
The use of image receiving materials in the silver complex diffusion 
transfer reversal (DTR-) process is well known state of the art. 
A more recently developed diffusion transfer reversal process is based on 
the image-wise transfer of diffusible dye molecules from an image-wise 
exposed silver halide emulsion material into a waterpermeable image 
receiving layer containing a mordant for the dye(s). The image-wise 
diffusion of the dye(s) is controlled by the development of one or more 
image-wise exposed silver halide emulsion layers, that for the production 
of a multicolour image are differently spectrally sensitized and contain 
respectively a yellow, magenta and cyan dye molecules. A survey of dye 
diffusion transfer imaging processes has been given by Christian C. Van de 
Sande in Angew. Chem. - Ed. Engl. 22 (1983) n.degree. 3, 191-209. 
For use in dye diffusion transfer photography the type of mordant chosen 
will depend upon the dye to be mordanted. If acid dyes are to be 
mordanted, the image-receiving layer contains basic polymeric mordants 
such as polymers of amino-guanidine derivatives of vinyl methyl ketone 
such as described in U.S. Pat. No. 2,882,156, and basic polymeric mordants 
and derivatives, e.g. poly-4-vinylpyridine, the metho-p-toluene sulphonate 
of 2-vinylpyridine and similar compounds described in U.S. Pat. No. 
2,484,430, and the compounds described in the published DE-A 2,009,498 and 
2,200,063. Other mordants are long-chain quaternary ammonium or 
phosphonium compounds of ternary sulphonium compounds, e.g. those 
described in U.S. Pat. Nos. 3,271,147 and 3,271,148, and 
cetyltrimethyl-ammonium bromide. Certain metal salts and their hydroxides 
that form sparingly soluble compounds with the acid dyes may be used too. 
The dye mordants are dispersed or molecularly divided in one of the usual 
hydrophilic binders in the image-receiving layer, e.g. in gelatin, 
polyvinyl alcohol, polyvinylpyrrolidone or partly or completely hydrolysed 
cellulose esters. 
In U.S. Pat. No. 4,186,014 cationic polymeric mordants are described that 
are particularly suited for fixing anionic dyes, e.g. sulphinic acid salt 
dyes that are image-wise released by a redox-reaction described in U.S. 
Pat. No. 4,232,107. 
Said cationic polymeric mordants contain glycidyl groups that can react 
with active hydrogen atoms being present in gelatin serving as binding 
agent. Such polymers can be made by quaternizing a basic polyurethane, 
polyurea or polyurea-polyurethane with a quaternizing agent capable of 
introducing glycidyl groups. 
The mordant layer contains preferably said cationic polymeric mordant in 
quantities of from 10 to 70% by weight based on the total solids content 
of the mordant layer. An image receiving layer on the basis of said 
mordant is applied to polyester resin supports. 
When as support for the above composed image receiving layer a support of a 
vinyl chloride polymer is used, that is preferred for use in the 
production of laminates by heat sealing, there is a problem with the 
adherence of said receiving layer to the support. The dye image receiving 
layer on a vinyl chloride support must remain securely anchored thereto in 
dry as well as in wet conditions. Such is particularly important when 
vinyl chloride supports are used in the production of tamperproof 
identification cards. 
In accordance with the invention described in U.S. Pat. No. 4,772,536 an 
image receiving material suitable for image production by dye diffusion 
transfer processing controlled by the development of (an) image-wise 
exposed silver halide emulsion layer(s) is provided, wherein the support 
of said material is substantially consisting of a vinyl chloride polymer 
and the support is coated with an image receiving layer containing gelatin 
in admixture with a cationic polymeric mordant containing glycidyl groups 
that can react with active hydrogen atoms of the gelatin, the weight ratio 
of said polymeric mordant to gelatin being from 25:1 to 2.5:1, preferably 
being 5:1, and the gelatin being present at a coverage of at least 0.1 g 
per m2. 
Although gelatin is one of the most common hydrophilic colloid binding 
agents for forming waterpermeable coatings in which photographic 
ingredients can diffuse easily it has some disadvantages in the 
preparation of such coatings because its dissolving or transformation in 
sol state is preceded by a rather time consuming swelling in water mostly 
at elevated temperature. 
Moreover, gelatin containing coatings require the use of a subbing layer to 
adhere properly to a hydrophobic resin support such as a vinyl chloride 
resin support and therefore it would be very advantageous if such subbing 
layer could be omitted. 
It is an object of the present invention to provide an image receiving 
material containing a supported waterpermeable image receiving layer 
suitable for carrying out a dye diffusion transfer processing controlled 
by the development of a photo-exposed silver halide emulsion layer wherein 
said image receiving layer is free from gelatin and contains a mordant for 
fixing dyes transferred by diffusion. 
It is another object of the present invention to provide an image receiving 
material containing a supported waterpermeable image receiving layer 
suitable for carrying out a dye diffusion transfer processing controlled 
by the development of a photo-exposed silver halide emulsion layer wherein 
said image receiving layer containing a mordant and being free from 
gelatin is coated directly onto a hydrophobic resin support, e.g. 
polyvinyl chloride resin support and adheres thereto very well in dry as 
well as in wet state. 
It is an other object of the present invention to use said image receiving 
material in the production of heat- and pressure sealed laminates that may 
serve as identification document. 
Other objects and advantages of the present invention will appear from the 
following description. 
In accordance with the present invention an image receiving material 
suitable for image production by dye diffusion transfer processing 
controlled by the development of (an) image-wise exposed silver halide 
emulsion layer(s) is provided, wherein said image receiving material 
comprises a supported image receiving layer free from gelatin and 
containing (1) a cationic polymeric mordant, and (2) colloidal silica 
applied from an aqueous acidic colloidal sol having a pH of not more than 
4, and containing hydrated silica in combination with a smaller amount of 
colloidal alumina, the amount of said colloidal material to said mordant 
in the image-receiving layer being in a weight ratio range from 1/5 to 
1/2, and silica (SiO.sub.2) being present at a coverage of at least 0.5 g 
per m2. 
The above mentioned acidic sol can be prepared by addition of aluminium 
trihalide, preferably aluminium trichloride, to a basic aqueous colloidal 
silica sol producing that way in situ colloidal alumina forming an 
intimate mixture with the colloidal silica, e.g. in an amount from 5 to to 
15% by weight of Al.sub.2 O.sub.3 with respect to SiO.sub.2. 
According to a preferred embodiment the colloidal silica has a surface area 
of at least 100 m2 per gram, more preferably in the range of 200 to 300 m2 
per gram. 
The surface area of the colloidal silica is determined acording to the 
method described by Nelsen and Eggertsen in "Determination of Surface Area 
Adsorption Measurements by Continuous Flow Method", Analytical Chemistry, 
Vol. 30, No. 8 (1958) 1387-1390. 
Optionally said image-receiving layer contains a non-proteinaceous 
colloidal binding agent such as polyvinylalcohol and/or 
poly-N-vinylpyrrolidinone. The polyvinylalcohol is preferably a 
watersoluble practically completely (at least 90%) hydrolyzed polyvinyl 
acetate with an average molecular weight in the range of 18,000 to 
200,000. 
A preferred poly-N-vinylpyrrolidinone has an average molecular weight of 
about 25,000. When present said binding agents are used preferably in a 
weight ratio range of 1/10 to 1/4 with respect to the colloidal SiO.sub.2. 
The image receiving layer composition can be coated directly to a 
hydrophobic resin support, e.g. made of a vinyl chloride polymer, since it 
has a good adherence thereto in dry as well as in wet state. 
The term "vinyl chloride polymer" includes the homopolymer, as well as any 
copolymer containing at least 50% by weight of vinyl chloride units and 
including no hydrophilic recurring units. 
Vinyl chloride copolymers which may serve as the support may contain one or 
more of the following comonomers: vinylidene chloride, vinyl acetate, 
acrylonitrile, styrene, butadiene, chloroprene, dichlorobutadiene, vinyl 
fluoride, vinylidene fluoride, trifluorochloroethylene, and 
tetrafluoroethylene. 
The vinyl chloride polymer serving as the support may be chlorinated to 
contain 60-65% by weight of chlorine. 
Many properties of polyvinyl chloride and its copolymers are improved by 
plasticization and their stability can be improved by stabilizers well 
known to those skilled in the art (see, e.g., F.W.Billmeyer, Textbook of 
Polymer Chemistry, Interscience Publishers, Inc., New York (1957) p. 
311-315)). 
The resin support, e.g. vinyl chloride polymer support, may contain 
pigments or dyes as colouring matter e.g. in an amount up to 5% by weight. 
An opaque white appearance may be obtained by incorporation of white 
pigments, e.g. titanium dioxide particles. 
A preferred cationic polymeric mordant for use in the image-receiving 
material according to the present invention contains glycidyl groups that 
can react with hydroxyl groups of the hydrated silica. Such a mordant is 
e.g. a basic polyurethane polyurea or polyurea-polyurethane consisting of 
from 0 to 30 mole % of recurrent units derived from a modifying monomer 
selected from the group consisting of monofunctional and trifunctional 
alcohols, amines, and isocyanates and from 70 to 100 moles % of recurrent 
units of the general formula: 
EQU (--A--B--) 
in which segment A is derived from a diol, hydroxy alkylamine or diamine 
containing at least one tertiary amino group and by removal of two 
terminal hydrogen atoms corresponds to the general formula: 
##STR1## 
wherein: R.sub.1 represents a straight or branched chain alkyl, 
alkoxyalkyl, aralkyl, a disubstituted aminoalkyl group of the formula: 
##STR2## 
or an ethylene or 1,2-propylene group which is attached to X.sub.1 or 
X.sub.2 through the second bond with formation of a piperazine ring, 
R.sub.2 and R.sub.3 which may be the same or different represent alkyl 
groups having from 1 to 4 carbon atoms or together represent the atoms 
required to complete a pyrrolidine, piperidine or morpholine ring, 
X.sub.1 and X.sub.2 which may be the same or different, represent --O--, 
--NH--, --NR.sub.4 -- or a group of the formula --NR.sub.4 
--(CH.sub.2).sub.m4 --X.sub.3 -- 
in which: 
R.sub.4 represents an alkyl group having from 1 to 4 carbon atoms, 
X.sub.3 represents --O--, --NH-- or --NR.sub.4 -- and may be the same as or 
different from X.sub.1 and X.sub.2, and 
m1 to m4 represent 2 or 3, and 
wherein segment A contains up to 40% of the tertiary amino group being 
quaternized with a quaternizing agent carrying glycidyl groups, and the 
remainder of the tertiary amino groups being: 
(i) quaternized with quaternizing agents absent glycidyl groups, or 
(ii) neutralized with an acid, and 
in which segment B is derived from a bis-chloroformate, a diisocyanate or 
an isocyanate prepolymer having two isocyanate end groups, and corresponds 
to the formula: 
EQU --CO--Y--CO-- 
wherein Y represents, --O--R.sub.5 --O--, --NH--R.sub.6 --NH-- or 
--NH--R.sub.6 --NH--CO--O--R.sub.7 --O--CO--NH--R.sub.6 --NH--, provided 
that Y can represent --OR.sub.5 O-- only when X.sub.1 or X.sub.3 are not 
--O--, 
wherein: 
R.sub.5 represents an alkylene group unsubstituted or substituted by an 
alkyl group or interrupted by ether oxygen atoms, 
R.sub.6 represents an alkylene group unsubstituted or substituted with 
alkyl groups, a cycloalkylene group or an arylene group, and 
R.sub.7 represents any divalent group not containing any other Zerewitinoff 
active group or a group capable of reacting with isocyanate groups. 
The preparation of said cationic polymeric mordant proceeds as described in 
U.S. Pat. No. 4,186,014. 
A mordant having particularly good fixing power for anionic dyes is called 
mordant A and has the following structure (the percentage values are mole 
%): 
##STR3## 
Said mordant is prepared analogously to Example 12 of U.S. Pat. No. 
4,186,014. 
Generally, good results are obtained when the dye image-receiving layer is 
about 2 to about 10 .mu.m thick. This thickness, of course, can be 
modified depending upon the result desired. The image-receiving layer may 
also contain ultraviolet-absorbing materials to protect the mordanted dye 
images from fading, brightening agents such as the stilbenes, coumarins, 
triazines, oxazoles, dye stabilizers such as the chromanols, 
alkyl-phenols, etc. 
The image receiving layer in the dye image receiving material according to 
the present invention has a high resistance to abrasion and yields very 
rapidly a touch dry dye image. 
The coating of the image-receiving layer composition according to the 
present invention onto a resin support proceeds preferably for reducing 
repellence and for allowing a higher coating speed onto a corona discharge 
pre-treated resin support. Paper supports do not need such pre-treatment. 
According to an embodiment of corona discharge treatment the resin support 
or resin coated paper support, e.g. in sheet or belt form, is led between 
a grounded conductive roller and corona wires whereto an alternating 
current (AC) voltage is applied with sufficiently high potential to cause 
ionization of the air. Preferably the applied peak voltage is in the range 
of 10 to 20 kV. An AC corona unit is preferred because it does not need 
the use of a costly rectifier unit and the voltage level can be easily 
adapted with a transformer. In corona-discharge treatment with an an AC 
corona unit a frequency range from 10 to 100 kHz is particularly useful. 
The corona-treatment can be carried out with material in the form of a 
belt or band at a speed of 10 to 30 m per min while operating the corona 
unit with a current in the range of 0.4 to 0.6 A over a belt or band width 
of 25 cm. 
The corona-discharge treatment makes it possible to dispense with a solvent 
treatment for attacking and roughening the surface of the resin support 
and is less expensive and more refined in its application. 
The image-receiving layer can form part of a separate image-receiving 
material or form an integral combination with the light-sensitive layer(s) 
of the photographic material. 
Where after processing of the photosensitive material the image-receiving 
layer applied on a support remains associated with a processed silver 
halide emulsion layer(s) that had been coated thereon, an alkali-permeable 
light-shielding layer, e.g. containing white pigment particles is applied 
between the image-receiving layer and the silver halide emulsion layer(s) 
to mask the negative image with respect to the positive image as described 
e.g. in the book: "Photographic Silver Halide Diffusion Processes" by 
Andre Rott and Edith Weyde--The Focal Press--London--New York (1972) page 
141. 
After the obtaining of the dye image in the image receiving layer it is 
advantageous to remove adhering chemicals stemming from e.g. the 
photographic processing or used in that processing. It has been 
established experimentally that chemicals such as photographic silver 
halide developing agents impair the adherence in a lamination step, e.g. 
as referred to hereinafter, and therefore a cleaning step is preceding 
preferably the lamination for removing these chemicals. The cleaning 
proceeds preferably with the aid of a dissolved detergent that diminishes 
the surface tension in aqueous medium. Any commercial detergent can be 
used for that purpose. A survey of detergents can be found in the book: 
"McCutcheon's Detergents & Emulsifiers 1978 North American Edition - 
McCutcheon Division, MC Publishing Co. 175 Rock Road, Glen Rock, N.J. 
07452 U.S.A. Preference is given to anionic and non-ionic surface-active 
agents containing a polyethyleneoxide chain in their structure. Examples 
of such agents are described in U.S. Pat. No. 3,663,229. 
In order to obtain a less hydrophilic image-receiving layer with better 
adherence to a hydrophobic resin top coat the dye image containing layer 
is treated with a siloxane. Preferred siloxane compounds for that purpose 
are within the scope of the following general formula: 
##STR4## 
wherein: R.sup.11 represents a group containing reactive halogen such as a 
reactive chlorine atom, an epoxy group or an alpha,beta-ethylenically 
unsaturated group, representatives of such groups being e.g. the 
following: 
EQU Cl--CH.sub.2 --CO--NH--L-- 
EQU Br--CH.sub.2 --CO--NH--L-- 
##STR5## 
wherein L represents an alkylene group preferably a C.sub.1 -C.sub.4 
alkylene group, or R.sup.11 represents the group: 
##STR6## 
wherein Z is a bivalent hydrocarbon chain including such chain 
interrupted by oxygen, e.g. is a --CH.sub.2 --O--(CH.sub.2).sub.3 -- 
group, or a bivalent hydrocarbon group that is linked at the side of the 
silicon atom to oxygen, e.g. is a --CH.sub.2 --O-- group, and 
each of R.sup.12, R.sup.13 and R.sup.14 (same or different) represents a 
hydrocarbon group including a substituted hydrocarbon group e.g. methyl 
and ethyl. 
Siloxane compounds according to the above general formula are described in 
U.S. Pat. No. 3,661,584 and GB-P 1,286,467 as compounds improving the 
adherence of proteinaceous colloid compositions to glass. 
Examples of particularly useful siloxane compounds are listed in the 
following table 1. 
TABLE 1 
__________________________________________________________________________ 
##STR7## 1. 
##STR8## 2. 
##STR9## 3. 
##STR10## 4. 
##STR11## 5. 
##STR12## 6. 
##STR13## 7. 
__________________________________________________________________________ 
The present image-receiving layer is particularly suited for application in 
the production of laminar articles comprising a dye image making part of 
an identification document, also called I.D. card, that contains a colour 
photograph by lamination sandwiched between a clear plastic protective 
cover sheet and a rear possibly opaque support sheet. 
In view of the widespread use of I.D. cards as security document, e.g. to 
establish a person's authorization to conduct certain activities (e.g. 
driver's licence) or to have access to certain areas or to engage in 
particular commercial actions, it is important that forgery of the I.D. 
card by alteration of certain of its data and/or photograph is made 
impossible. 
In a particular useful embodiment a laminar article according to the 
present invention comprises the above defined image receiving layer 
incorporating a dye image enveloped between a vinyl chloride polymer 
support and a resin cover sheet fixed to the image receiving layer by 
lamination using pressure and heat. 
According to a preferred embodiment the cover sheet is a polyethylene 
terephthalate sheet being coated with a resinous melt-adhesive layer, 
preferably a polyethylene layer. 
The lamination of the present image receiving material with a covering 
hydrophobic resin film sheet material proceeds preferably by heat-sealing 
between flat steel plates under a pressure of e.g. 10 to 15 kg/cm2 at a 
temperature in the range of 120 to 150.degree. C., e.g. at 135.degree. C 
or by using other apparatus available on the market for heat sealing 
lamination purposes, e.g. hot pressure roller sealer. The cooling of the 
heat-sealed elements proceeds preferably under pressure to avoid 
distortion. 
The laminate may contain the image receiving layer over the whole area of 
the support or in a part thereof, e.g. leaving free the edge area as 
described in U.S. Pat. No. 4,425,421. 
According to an embodiment the image receiving layer is coated onto an 
opaque polyvinyl chloride having a thickness of only 0.050 to 0.300 mm. A 
sheet of that thickness can receive printed data by means of a mechanical 
printing process, e.g. offset or intaglio printing. It can receive, before 
or after being coated with the image receiving layer, or before or after 
the dye transfer, additional security marks in the form of e.g. a 
watermark, finger prints, printed patterns known from banc notes, coded 
information, e.g. binary code information, signature or other printed 
personal data that may be applied with visibly legible or ultra-violet 
legible printing inks as described e.g. in GB-P 1,518,946 and U.S. Pat. 
No. 4,105,333. 
Other possibilities to increase security against counterfeiting are the 
inclusion in the laminate of markings of nacreous pigments, infra-red 
absorbing markings, magnetic dots or strips and electronic microcircuits 
either or not combined with ultra-violet radiation absorbing markings 
hidden from visibility and/or holograms as described e.g. in DE-OS 2 639 
952, GB-P 1,502,460 and 1,572,442 and U.S. Pat. No. 3,668,795. The 
holographic patterns may be obtained in silver halide emulsion layers, 
normally Lippmann emulsions, especially designed for that purpose and can 
either or not be combined with a photograph. 
According to an embodiment the silver halide emulsion layer for producing 
the hologram is applied on one side of the transparent cover sheet used in 
the manufacture of a laminate according to the present invention and 
laminated to the image receiving layer either or not separated therefrom 
by a transparent resin intersheet being made of polyethylene or a resin 
sheet such as a polyvinyl chloride sheet being coated with polyethylene. 
When the resin sheet used as support of the laminate has to possess a 
thickness required for an identification card to be inserted in a slot of 
an electronic identification apparatus several sheets of matted polyvinyl 
chloride are stacked and laminated so as to reach a final thickness of 
e.g. 0.075 to 1 mm. When this lamination to the desired thickness occurs 
after dye image formation on a relatively thin polyvinyl chloride support, 
treatment with detergent as referred to hereinbefore to remove adhering 
chemicals preferably preceeds the lamination. The laminar article contains 
in that case preferably in the polyvinyl chloride support sheet opacifying 
titanium dioxide and a suitable plasticizing agent. The support may be 
provided with an embossed structure. 
The following comparative example illustrates the present invention 
without, however, limiting it thereto. 
All parts, ratios and percentages are by weight unless otherwise stated.

EXAMPLE 
An opaque polyvinyl chloride sheet having a width of 24 cm and a thickness 
of 200 .mu.m was treated with an electrical discharge produced by a corona 
discharge apparatus operated under the following conditions: 
film travelling speed: 20 m/min, 
electrode spacing to film surface: 2 mm, 
corona current: 0.55 A, 
AC voltage difference (peak value): 10 kV, 
frequency: 30 kHz. 
Sample X 
The corona-treated surface was coated per m.sup.2 with the following 
aqueous coating composition to form thereon an image receiving layer X for 
dye diffusion transfer processing: 
______________________________________ 
water 160.9 ml 
mordant A (20% solution in water) 
266.0 ml 
water/ethanol (1/1 by volume) at pH 4 
92 ml 
aqueous wetting agent mixture W as coating aid 
32.0 ml 
aqueous hardening agent solution H 
50 ml 
aqueous acidic colloidal silica/alumina sol Z 
100 ml 
______________________________________ 
Aqueous wetting agent mixture W contains dissolved in water 12% of saponine 
and 5% of an iso-nonyl phenoxy wetting agent having following structural 
formula: 
##STR14## 
Aqueous hardening agent solution H consists of a 10% solution in water of 
formaldehyde. 
The aqueous acidic colloidal silica/alumina sol Z has a pH of 3.4 and 
contains 27 g of SiO.sub.2 and 3 g of Al.sub.2 O.sub.3 per 100 ml of 
water; it was obtained by adding AlCl.sub.3 to a basic aqueous silica sol 
containing colloidal silica with a surface area of 200 m.sup.2 /g. Said 
sol P is marketed by Bayer AG, Leverkusen, Bayerwerk (DE) under the 
registered trade name "KIESELSOL 200 S". 
Sample Y 
The corona-treated surface was coated per m.sup.2 with the following 
aqueous coating composition to form thereon an image receiving layer X for 
dye diffusion transfer processing: 
______________________________________ 
water 160.9 ml 
mordant A (20% solution in water) 
266.0 ml 
water/ethanol (1/1 by volume) at pH 4 
92 ml 
wetting agent mixture W as coating aid 
32.0 ml 
aqueous hardening agent solution H 
50 ml 
10% aqueous solution of poly-N-vinylpyrrolidinone 
100 ml 
(average molecular weight: 25,000) 
aqueous acidic colloidal silica/alumina sol Z 
100 ml 
______________________________________ 
Sample Z 
The corona-treated surface was coated per m.sup.2 with the following 
aqueous coating composition to form thereon an image receiving layer Y for 
dye diffusion transfer processing: 
______________________________________ 
water 160.9 ml 
mordant A (20% solution in water) 
266.0 ml 
water/ethanol (1/1 by volume) at pH 4 
92 ml 
wetting agent mixture W as coating aid 
32.0 ml 
aqueous hardening agent solution H 
50 ml 
5% aqueous solution of polyvinylalcohol 
50 ml 
(99-100% hydrolyzed polyvinylacetate) 
aqueous acidic colloidal silica/alumina sol Z 
100 ml 
______________________________________ 
Sample N (not within the scope of the invention) 
The corona-treated surface was coated per m.sup.2 with the following 
aqueous coating composition to form thereon an image receiving layer X for 
dye diffusion transfer processing: 
______________________________________ 
water 160.9 ml 
mordant A (20% solution in water) 
266.0 ml 
water/ethanol (1/1 by volume) at pH 4 
92 ml 
wetting agent mixture W as coating aid 
32.0 ml 
aqueous hardening agent solution H 
50 ml 
colloidal silica/alumina sol Z put at pH = 7 
100 ml 
______________________________________ 
Said compositions X, Y, Z and N were coated at a wet coverage of 26 m2/1. 
After coating the samples X, Y, Z and N were dried at 30.degree. C. and 
processed in combination with a photographic dye diffusion transfer 
material as described in the Example of U.S. Pat. No. 4,496,645. Said 
photographic material was exposed with white light through a grey wedge 
having a constant 0.1 and thereupon contacted for 1 minute with an image 
receiving material having the composition described hereinafter in a 
diffusion transfer apparatus COPYPROOF CP 38 (trade name of Agfa-Gevaert 
N.V. Belgium) having in its tray following composition: 
______________________________________ 
sodium hydroxide 25 g 
sodium orthophosphate 25 g 
cyclohexane dimethanol 25 g 
2,2'-methylpropylpropane diol 
25 g 
N-ethylbenzene-pyridinium chloride 
0.5 g 
distilled water up to 1000 ml 
______________________________________ 
After drying the thus treated samples were laminated with a transparent 
cover sheet being a polypropylene sheet having a thickness of 30 .mu.m 
coated at one side with a thermoadhesive layer of polyethylene having a 
thickness of 30 .mu.m. The lamination was carried out between flat steel 
plates pressing the layers together for 8 minutes using a pressure of 10 
kg/cm2 at a temperature of 135.degree. C. Said pressure was maintained 
during cooling to reach room temperature (20.degree. C.) again. 
The laminates with the samples X, Y and Z showed a sealing thus strong that 
on peeling apart the cover sheet the dye image was destroyed. 
The laminate containing sample N showed in wet state a poor adherence of 
the image receiving layer to its support that could be peeled apart after 
soaking the laminate in water at 20.degree. C. for 4 h.