Ink-receptive layers

Abstract: An image recording element is provided comprising a polymeric substrate (which includes a resin coated paper substrate) and an ink-receptive layer of at least one non-cellulosic binder characterised in that said layer has been applied from a coating solution the pH of which has been adjusted to a value between 7.5 and 11.

Description: 1. Field of the invention. This invention relates to image-recording elements that contain a polymeric substrate on which are coated ink-receptive layers that can be imaged by the application of liquid ink dots (e.g. by ink-jet printers). 2. Description of the Prior Art. Polymeric substrates are becoming more important in the manufacture of ink-receiving elements for ink-jet printing (e.g. resin coated paper, polyesterfilm, etc). One of the applications of image-recording elements on a polymeric substrate for ink-jet printing is the production of transparencies. These elements are primarily intended for use on an overhead projector. More generally, these elements can be used for all kinds of viewing means by transmitted light. Such a transparency for overhead projection can easily be created by applying liquid ink dots to the ink-receptive layer using equipment such as ink jet printers. In the ink jet printing technique the individual ink droplets can be applied to the receiving substrate in several different ways. The ink solution can be jetted continuously through a small nozzle toward the receiving layer (Hertz method). The ink droplet can also be created "upon demand" by a piezoelectric transducer or a thermal push (Bubble Jet). It is known that the ink-receptive layers of image-recording elements must meet different stringent requirements. Two of these requirements are : a high ink absorbing capacity, so that the dots will not flow out and will not be expanded more than is necessary to obtain a high optical density, even if ink droplets in a multi-color system may be superposed on the same physical spot. a high ink absorbing speed (short ink drying time) so that the ink droplets will not feather if smeared immediately after applying. When using plain paper or textile (cellulosic fibres) as the ink receiving layer it has been described that a pretreatment of the ink receiving layer with a strong basic solution improves the water-fastness and the smear resistance of ink in which a reactive moiety is attached to a chromophore (EP A1 429171 and JP 63 145379). The use of reactive dyes in the ink poses an economic problem, these speciality inks are much more expensive than the normal water soluble non reactive inks. For generating transparencies by a computer it is preferred that the consumables are cheap, which excludes the use of speciality inks. A transparant plastic, dimensionally stable substrate (e.g. Polyethyleneterephthalate or Cellulose-triacetate) or a resin coated paper as the substrate for the ink receiving layer has to be coated with a layer comprising one or more binders (e.g. Gelatin, Polyvinylalcohol (PVA), Polyvinylpyrrolidone (PVP), etc) to have good ink-receiving characteristics. It is preferred, for ecological reasons, to coat the ink receiving layer on a polymeric substrate out of an aquous solution of gelatine, PVA, PVP or mixtures of those three. When ink-jetting on such substrates a big advantage for maximum density and drying time can be obtained by using particulates in the binder. Many patent applications have described this effect for many different binder-systems. US P 3 357 846 describes pigments such as kaolin, talc, baryta, TiO 2 used in starch and PVA. US P 3 889 270 describes silica in gelatin, PVA and cellulose. Pigments and particles have also been described in patent applications DE 2 925 769, GB 2 050 866, US P 4 474 850, US P 4 547 405, US P 4 578 285, WO 88 06532, US P 4 849 286, EP 339 604, EP 400 681, EP 407 881, EP 411 638 and US P 5 045 864. The addition however of such particulates to a binderlayer tend to diminish the transparency of the layer which limits the amount of particulates that are tolerable in the layer and hence the usefulness of the addition in enhancing the smear resistance by shortening the drying time. 3. Object of the invention. It is an object of the invention to provide an image-recording element that comprises a polymeric film or a resin coated paper as a support and an ink-receptive layer coated thereon in which the element is adapted for use in a printing proces where liquid ink dots are applied to it with a high resolution, where the element can be printed with normal, readily available inks and has a short drying time, so that no problems arrive if the element is handled shortly after being printed. 4. Summary of the invention. We have now found that the above objects are accomplished by coating the substrate with a non cellulosic gel-forming binder solution and adjusting the pH of the aqueous coating solution to a pH-value between 7.5 and 11. In this way an image-recording element is achieved which is adapted for use in a printing process where liquid ink dots are applied to an ink-receptive layer and in which the ink-receptive layer is excellent in view of drying time after being printed with the aqueous non reactive ink. The present invention thus provides an image recording element comprising a polymeric substrate (which includes a resin coated paper substrate) and an ink-receptive layer of at least one non-cellulosic binder characterised in that said layer has been applied from a coating solution the pH of which has been adjusted to a value between 7.5 and 11. According to a preferred embodiment of the invention, gelatine is used as the binder and the pH of the coating solution adjusted to a pH between 8.5 and 10.5. 5. Detailled description. The coating solution of the ink-receptive layers in the novel transparent image-recording elements of this invention comprises a binder or a mixture of compatible binders, and a pH regulating agent providing to the coating solution a pH-value between 7.5 and 11. The present invention is based upon the discovery that the regulation of the pH value of the coating solution used to prepare an ink-receiving layer can result in a big improvement of drying time characteristics. The ink-receptive layer in the novel transparent image-recording elements of this invention contains a binder which is selected from the group consisting of: (1) polyvinyl alcohol; (2) polyvinyl acetate; (3) polyvinylacetal;(4) polyvinyl pyrrolidone; (5) polyacrylamide; (6) acrylamide/acrylic acid copolymer; (7) styrene/acrylic acid copolymer; (8) ethylene-vinylacetate copolymer; (9) vinylmethyl ether/maleic acid copolymer; (10) poly(2-acrylamido-2-methyl propane sulfonic acid); (11) poly(diethylene triamine-co-adipic acid); (12) polyvinyl pyridine; (13) polyvinylimidazole; (14) polyimidazoline quaternized; (15) polyethyleneimine epichlorohydrin-modified; (16) polyethyleneimineethoxylated; (17) poly(N,N-dimethyl-3,5-dimethylene piperidiniumchloride; (18) polyethylene oxide; (19) polyurethane; (20) melamin resins; (21) epoxy resins; (22) urea resins; (23) styrene-butadiene rubbers; (24) chloroprene rubbers; (25) nitrilerubbers; (26) gelatin; (27) carrageenan; (28) dextran; (29) gumarabic; (30) casein; (31) pectin; (32) albumin; (33) starch; (34) collagen derivatives; (35) collodion and (36) agar-agar. Specific examples of hydrophilic ink receiving layer coatings for ink jet printing, according to the present invention, include binary blends consisting of from about 10 to about 90 precent by weight of gelatin and from about 90 to about 10 percent by weight of a component selected from the group consisting of : (1) polyvinyl alcohol; (2) polyvinyl acetate; (3) polyvinylacetal;(4) polyvinyl pyrrolidone; (5) polyacrylamide; (6) acrylamide/acrylic acid copolymer; (7) styrene/acrylic acid copolymer; (8) ethylene-vinylacetate copolymer; (9) vinylmethyl ether/maleic acid copolymer; (10) poly(2-acrylamido-2-methyl propane sulfonic acid); (11) poly(diethylene triamine-co-adipic acid); (12) polyvinyl pyridine; (13) polyvinylimidazole; (14) polyimidazoline quaternized; (15) polyethyleneimine epichlorohydrin-modified; (16) polyethyleneimineethoxylated; (17) poly(N,N-dimethyl-3,5-dimethylene piperidiniumchloride; (18) polyethylene oxide; (19) polyurethane; (20) melamin resins; (21) epoxy resins; (22) urea resins; (23) styrene-butadiene rubbers; (24) chloroprene rubbers; (25) nitrilerubbers; (26) carrageenan; (27) dextran; (28) gumarabic; (29) casein; (30) pectin; (31) albumin; (32) starch; (33) collagen derivatives; (34) collodion and (35) agar-agar. Very interesting examples of hydrophilic ink receiving layer coatings for use in ink jet printing as described in this invention include ternary blends comprised of from about 10 to about 50 percent by weight of gelatin, from about 85 to about 5 percent by weight of polyvinyl pyrrolidone and from about 5 to about 45 percent by weight of a component selected from the group consisting of : (1) polyvinyl alcohol; (2) polyvinyl acetate; (3) polyvinylacetal; (4) polyacrylamide; (5) acrylamide/acrylic acid copolymer; (6) styrene/acrylic acid copolymer; (7) ethylene-vinylacetatecopolymer; (8) vinylmethyl ether/maleic acid copolymer; (9) poly(2-acrylamido-2-methyl propane sulfonic acid); (10) poly(diethylene triamine-co-adipic acid); (11) polyvinylpyridine; (12) polyvinyl imidazole; (13) polyimidazoline quaternized; (14) polyethylene imine epichlorohydrinmodified; (15) polyethylene imine ethoxylated; (16) poly(N,N-dimethyl-3,5-dimethylene piperidinium chloride; (17) polyethylene oxide; (18) polyurethane; (19) melamin resins; (20) epoxy resins; (21) urearesins; (22) styrene-butadiene rubbers; (23) chloroprene rubbers;(24) nitrile rubbers; (25) carrageenan; (26) dextran; (27) gumarabic; (28) casein; (29) pectin; (30) albumin; (31) starch; (32) collagen derivatives; (33) collodion and (34) agar-agar. Illustrative specific examples of binary (two polymers) and ternary (three polymers) blends selected as ink receiving polymers for ink jet printing according to this invention, include binary blends of gelatin, 80 percent by weight and polyethylene oxide, 20 percent by weight; binary blends of gelatin, 70 percent by weight, and polyvinyl pyrrolidone, 30 percent by weight; ternary blends of gelatin, 60 percent by weight, polyvinyl pyrrolidone, 20 percent by weight, and polyvinyl alcohol, 20 percent by weight and the like. Gelatin is thus a particularly preferred material for use in forming the ink-receiving layer of transparency materials according to this invention. Among the reasons is the fact that it forms a clear coating, is readily cross-linked in an easily controllable manner, and is highly absorptive of water-based liquid inks to thereby provide rapid-drying characteristics. The ink-receiving layer is preferably cross-linked in the image-recording elements of the invention to provide such desired features as water-fastness and non-blocking characteristics. The cross-linking is also useful in providing abrasion resistance and resistance to the formation of fingerprints on the element as a result of handling. There are a vast number of known cross-linking agents - also known as hardening agents - that will function to cross-link film forming materials, and they are commonly used in the photographic industry to harden gelatin emulsion layers and other layers of photographic silverhalide elements. Hardening agents can be used individually or in combination and in free or in blocked form. A great many hardeners, useful for the present invention, are known, including formaldehyde and free dialdehydes, such as succinaldehyde and glutaraldehyde, blocked dialdehydes, active esters, sulfonate esters, active halogen compounds, s-triazines and diazines, epoxides, active olefins having two or more active bonds, active olefins, carbodiimides, isoxazolium salts unsubsituted in the 3-position, esters of 2-alkoxy-N-carboxy-dihydroquinoline, N-carbamoyl and N-carbamoylpyridinium salts, hardeners of mixed function, such as halogen-substituted aldehyde acids (e.g. mucochloric and mucobromic acids), onium substituted acroleins and vinyl sulfones and polymeric hardeners, such as dialdehyde starches and copoly(acroleinmethacrylic acid). The ink-receptive layer in the novel transparent image-recording elements of this invention may also comprise particulate material, which may consist either of primary particles comprising single particles or of porous particles comprising secondary particles formed from aggregation of the primary particles. Among these particulate materials, particularly preferrable are porous particles having an average particle size of 1-30 µm, preferably 3-10 µm which can be formed by aggregation of smaller particles, having a size of 0.01 to 2 µm, preferably 0.1 to 0.5 µm. These porous particles formed by secondary or tertiary aggregation will not easily disintegrate. The porous material is preferably made of at least one of the organic materials such as polystyrene, polymethacrylate, polymethylmethacrylate, elastomers, ethylene-vinyl acetate copolymers, polyesters, polyester-copolymers, polyacrylates polyvinylethers, polyamides, polyolefines, polysilicones, guanamine resins, polytetrafluoroethylenes, SBR, NBR, urea resins, urea-formalin resins, etc., or inorganic materials such as synthetic silica, talc, clay, koalin, diatomaceous earth, calcium carbonate, magnesium carbonate, aluminium hydroxide, aluminium oxide, titanium oxide, zinc oxide, barium sulfate, calcium sulfate, zinc sulfide, satin white, aluminium silicate, calcium silicate, lithopone, etc. The specific surface area of the particulate material may vary from 10 to 200 m 2 /g (BET specific surface), and the oil absorption index may range from 5 10 -6 to 3.5 10 -5 ms -1/2 . Polymethylmethacrylate beads are preferred as matte agents. They are usually added to the receptive layer in a range of 0.4 to 1.2 g/m 2 and preferably in a range of 0.40 to 0.90 g/m 2 with 0.50 g/m 2 being most preferred. When the element is intended for vieuwing in reflection, the ink-receiving layer of the invention may contain a whitening agent. TiO2 is preferrably used as whitening agent in an amount sufficient to produce in the film element a transmission density to white light of at least 0.05, and preferably 0.3 or higher. Amounts of whitener present in the film element can range from 0.1 to 2.0 g/m 2 , and preferably from 0.2 to 0.5 g/m 2 , and most preferably 0.3g/m 2 . A slurry of the whitener may be added by batchwise addition or by in-line injection just prior to coating the receptor layer(s) on the support. The ink-receiving layer of the present invention can also comprise a softener such as ethylene glycol, dietylene glycol, propylene glycol, polyethylene glycol, glycerol monomethylether, glycerol monochlorohydrin, ethylene carbonate, propylene carbonate, tetrachlorophthalic anhydride, tetrabromophthalicanhydride, urea phosphate, triphenylphosphate, glycerolmonostearate, propylene glycol monostearate, tetramethylene sulfone, n-methyl-2-pyrrolidone, n-vinyl-2-pyrrolidone, and polymer latices with low Tg-value such as polyethylacrylate, polymethylacrylate, etc. The ink receiving layer of the present invention can also comprise a mordanting polymer, such as for instance a basic polymer latex comprising tertiary amino- or quaternary ammonium groups as described in US P 4371582; a hydrophilic polymer with up to 50% by weight of vinylpyridine/vinylbenzylquaternary ammonium salt copolymers (US P 4575465); quaternary ammonium derivatives as described in US P 4649064; and acrylcopolymers with ammonium radicals as described in EP A1 423829. Surfactants may be incorporated in the ink-receptive layer of the present invention. They can be any of the cationic, anionic, amphoteric, and nonionic ones as described in JP-62-280068 (1987). Examples of the surfactants are soap, N-alkylamino acid salts, alkylether carboxylic acid salts, acylated peptides, alkylsulfonic acid salts, alkylbenzene and alkylnaphthalene sulfonic acid salts, sulfosuccinic acid salts, a-olefin sulfonic acid salts, N-acylsulfonic acid salts, sulfonated oils, alkylsulfonic acid salts, alkylether sulfonic acid salts, alkylallylethersulfonic acid salts, alkylamidesulfonic acid salts, alkylphosphoric acid salts, alkyletherphosphoric acid salts, alkylallyletherphosphoric acid salts, alkyl and alkylallylpolyoxyethylene ethers, alkylallylformaldehyde condensed acid salts, alkylallylethersulfonic acid salts, alkylamidesulfonic acid salts, alkylphosphoric acid salts, alkyletherphosphoric acid salts, alkylallyletherphosphoric acid salts, alkyl and alkylallylpolyoxyethylene ethers, alkylallylformaldehyde condensed polyoxyethylene ethers, blocked polymers having polyoxypropylene, polyoxyethylene polyoxypropylalkylethers, polyoxyethyleneether of glycolesters, polyoxyethyleneether of sorbitanesters, polyoxyethyleneether of sorbitolesters, polyethyleneglycol aliphatic acid esters, glycerol esters, sorbitane esters, propyleneglycol esters, sugar-esters, fluoro C2-C10 alkylcarboxylic acids, disodium N-perfluorooctanesulfonyl glutamate, sodium 3-(fluoro-C6-C11alkyloxy)-1-C3-C4 alkyl sulfonates, sodium 3-(ω-fluoro-C6-C8 alkanoyl-N-ethylamino)-1-propane sulfonates, N-[3-(perfluorooctanesulfonamide)-propyl]-N,N-dimethyl-N-carboxymethylene ammonium betaine, fluoro-C11-C20 alkylcarboxylic acids, perfluoro C7-C13 alkyl carboxylic acids, perfluorooctane sulfonic acid diethanolamide, Li K and Na perfluoro C4-C12 alkyl sulfonates, N-propyl-N-(2-hydroxyethyl)perfluorooctane sulfonamide, perfluoro C6-C10 alkylsulfonamide propyl trimethyl ammonium salts, potassium perfluoro C6-C10 alkyl-N-ethylsulfonyl glycinates, bis-(N-perfluorooctylsulfonyl-N-ethanolaminoethyl)phosphonate, mono-perfluoro C6-C16 alkyl-ethyl phosphonates, and perfluoroalkylbetaine. Especially useful are the fluorocarbon surfactants as described in e.g. US P 4 781 985, having a structure of: F(CF 2 ) 4-9 CH 2 CH 2 SCH 2 CH 2 N + R 3 X - with R=hydrogen or alkyl-group; and in US P 5 084 340, having a structure of: CF 3 (CF 2 ) m CH 2 CH 2 O(CH 2 CH 2 O) n R with m=2-10; n=1-18; R=hydrogen or alkyl of 1 to 10 carbon atoms. These surfactants are commercially available from DuPont and 3M. The concentration of the surfactant component in the ink-receptive layer is typically in the range of 0.1 to 2 percent, preferably in the range of 0.4 to 1.5 percent and is most preferably 0.75 percent by weight based on the total dry weight of the layer. To enhance the water resistance of the ink images on the recording sheet, the ink-receiving layer of the present invention may contain a cationic surface-active agent and/or a cationic, water-soluble polymer. For example, the coating layer for receiving ink images may contain a water resisting agent consisting of a polycationic electrolytic polymer, for example, polyvinyl pyridium bromide or polyethylene imine, as disclosed in Japanese Unexamined Patent Publication No. 56-84992, dimethyldiallyl ammonium chloride as disclosed in Japanese Unexamined Patent Publication No. 59-20696, polyethylene imineorganic acid salts as disclosed in Japanese Unexamined Patent Publication No. 59-198186, polyalkylene polymine dicyandiamide ammonium salt-condensation products as disclosed in Japanese Unexamined Patent Publication No. 60-76386. The image-receiving layers of the present invention may additionally comprise different additives which are well known in the art, and include UV-filters and antistatic agents. The image-recording elements of this invention comprise a polymeric support for the ink-receptive layer. A wide variety of such supports are known and are commonly employed in the art. They include, for example, transparent supports as those used in the manufacture of photographic films including cellulose acetate propionate or cellulose acetate butyrate, polyesters such as poly(ethyleneterephthalate), polyamides, polycarbonates, polyimides, polyolefins, poly(vinylacetals), polyethers and polysulfonamides. Other examples of useful high-quality polymeric supports for the present invention include opaque white polyesters and extrusion blens of poly(ethylenenterephthalate) and polypropyleen. Polyester film supports and especially poly(ethyleneterephthalate) are preferred because of their excellent properties of dimensional stability. When such a polyester is used as the support material, a subbing layer must be employed to improve the bonding of the ink-receptive layer to the support. Useful subbing layers for this purpose are well known in the photographic art and include, for example, polymers of vinylidene chloride such as vinylene chloride/acrylonitrile/acrylic acid terpolymers or vinylidene chloride/methyl acrylate/itaconic acid terpolymers. The image-recording elements of this invention are employed in printing processes where liquid ink dots are applied to the ink-receiving layer of the element. A typical process is a ink-jet printing proces which involves a method of forming the image on a paper or transparency by ejecting ink droplets from a print head from one or more nozzles. Several schemes can be used to control the deposition of the ink droplets on the image-recording element to form the desired ink dot pattern used to build the image. For example, one method comprises deflecting electrically charged ink droplets by electrostatic means. Another method comprises the ejection of single droplets "upon demand" under the control of a piezoelectric device which can operate by volume change or "wall" motion, or under the control of a thermal excitation. The inks used to image the image-recording elements of this invention are well known to those skilled in the art. The ink compositions used in such printing processes as ink-jet printing are typically liquid compositions comprising a solvent or carrier liquid, dyes or pigments, humectants, organic solvents, detergents, thickeners, preservatives, etc. The solvent or carrier liquid is predominantly water, although ink in which organic materials such as polyhydric alcohols are used as carrier liquid, can also be used. The dyes used in such ink-jet ink compositions are typically water-soluble direct dyes or acid type dyes. Such liquid ink compositions have been extensively described in the prior art (US P 4381946, US P 4781758, US P 4994110). The following examples are presented to illustrate this invention, but are not limiting EXAMPLE 1 A polyethylene terephthalate film (PET-100 µm thick with typical photographic subbing layers, used for a better bonding between the PET and the gelatinous layers) was used as the substrate, The composition A was applied to this substrate with a pilot coating machine, so as to give a dry film-coating thickness of 5 µm; chilled at 5°C for 20 s; and dried at 35°C for 120 s (RH=30%). Composition A 70 parts of a gelatin with a gel strength higher than 220 g, the viscosity of a 10% solution of it at 40° C is higher than 50 mPas and containing 25 to 30 % microgels were mixed with 0.15 parts of Aerosol OT 75 a commercial product of American Cyanamid Co. Water was added to give 1000 parts The pH of the coating solution was adjusted by the addition of a sodium hydroxyde solution to pH 8. EXAMPLE 2 An ink-receiving transparent layer was prepared as described in example 1, except for the fact that the pH was adjusted to 9. REFERENCE EXAMPLE 3 A recording medium was prepared in the same way as in example 1 but with a pH adjustment of pH=5.0 by the addition of a solution of citric acid. The above described recording media were first acclimatised for at least 2 hours at 25°C and 30% RH, and then a test image was jetted upon it from a commercially available Hewlett-Packard PaintJet ink jet printer. Composition B was used as black ink for the experiment. Composition B Water 900 parts 1,5-pentanediol 65 parts Carboxymethycellulose 6 parts Poly(ethyleneoxide)-surfactant 5 parts Food Black 2 (commercial product of Bayer AG) 23 parts Sodium borate 1 part The quality of the print on the recording media prepared in this way was evaluated as follows: 1. The optical density of the three primary colors and black was measured by means of a Macbeth TR-1224 optical densitometer. All measurements for this transparent material were done in transparent mode. 2. The ink absorbency was evaluated as follows : a printout with several primary colors and black was made, so that there is a big time lap between the different blocks of the colors used. Immediately after finishing this print, a sandwich was made with a conventional Xerographic paper, the sandwich was conducted through a roller pair with constant pressure. After removal of the transparent material the optical density on the paper substrate was measured with a Macbeth TR-1224 optical densitometer. The optical density as a function of block number, i.e. as a function of time, was recorded. From these values a "decay time" was calculated. A small value indicates a better quality. The results of this evaluation are given in table 1. Example Comparative example 1 2 3 pH 8.0 9.0 5.0 Optical density 0.79 0.89 0.86 Ink absorbency 6 5 9 It is clearly shown that the ink-receiving layers according to the invention have a better ink absorbency with equal optical density. EXAMPLES 4-8 A recording medium was prepared in the same way as in example 1 but with gelatin having a gel strength ≥ 220 g and whereof the viscosity of a 10 % solution at 40° C is 41 mPas and having a microgel content of 20 to 25 %. The pH was adjusted by the addition of a solution of sodium hydroxyde as indicated in table 2. REFERENCE EXAMPLES 9-11 A recording medium was prepared in the same way as in example 4 but with a pH adjustment by the addition of a solution of citric acid as indicated in table 2. Printing was done by a commercially available Hewlett-Packard PaintJet and the ink cartridges that are normaly delivered with it (having three main colors and black). The results where evaluated as described for example 1 and 2 and comparative example 3. The results of the evaluation are also given in table 2. Example Comp. example 4 5 6 7 8 9 10 11 pH 7.5 8.0 9.0 10.0 11.0 2.0 3.0 5.0 OD_Y 0.57 0.55 0.56 0.56 0.54 0.55 0.53 0.52 OD_M 0.56 0.54 0.56 0.54 0.54 0.55 0.55 0.56 OD_C 1.16 1.15 1.15 1.11 1.05 1.13 1.30 1.20 OD_B 0.82 0.82 0.81 0.81 0.80 0.88 0.85 0.82 Ink absorbency 2 1 0 0 3 6 6 4 EXAMPLE 12 A coating solution for a transparent ink receiving layer was made as follows : Gelatine (the same as in examples 4 to 8 ) 80 parts Polyvynilpyrrolidone (MW 630.000) 20 parts Aerosol OT75 (Tradename of American Cyanamid Co) 0.4 parts Water to make 1000 parts The pH of this coating solution was adjusted by the addition of a solution of sodium hydroxyde to a value of 10. With this solution a recording medium was further prepared and treated in the same way as in example 1. COMPARATIVE EXAMPLE 13 A coating solution for a transparent ink receiving layer was prepared as in example 12, except for the pH-adjustment. In the comparative example the pH was adjusted to a value of 5.5 by adding a solution of citric acid to the coating solution. With this solution a recording medium was further prepared and treated in the same way as in example 1. Printing was done by a commercially available Hewlett-Packard DeskJet 500C and the ink cartridge that is normaly delivered with it (having three main colors and where black is generated by an overlay of Yellow, Magenta and Cyan). The results where evaluated as described for example 1 and 2 and comparative example 3. The results of the evaluation are also given in table 3. Example 12 Comparative example 13 pH 10.0 5.5 Optical density OD_Y 0.76 0.60 OD_M 0.65 0.56 OD_C 1.38 1.20 OD_B 0.98 0.84 Ink absorbency 0 4

Claims: An image recording element comprising a polymeric substrate and an ink-receptive layer of at least one non-cellulosic binder characterised in that said layer has been applied from a coating solution the pH of which has been adjusted to a value between 7.5 and 11. An image recording element according to claim 1 wherein said polymeric substrate is transparent. An image recording element according to claim 1 or 2 wherein said ink-receiving layer comprises at least one binder selected form the group of gelatin, polyvinyl pyrrolidone and polyvinyl alcohol. An image recording element according to any of the preceding claims where the pH of the coating solution has been adjusted to a pH between 8.5 and 10.5. An image recording element according to any of the preceding claims wherein said ink-receiving layer comprises a pigment. An image recording element according to any of the preceding claims wherein said ink-receiving layer comprises a softener. An image recording element according to any of the preceding claims wherein said ink-receiving layer comprises a surfactant. An image recording element according to any of the preceding claims wherein said ink-receiving layer comprises a UV-filter or an antistatic agent. Method of making an ink-receptive image recording element comprising the steps of coating a polymeric substrate with at least one non-cellulosic binder solution having a pH between 7.5 and 11, so as to form an ink-receptive layer on the said substrate.

Inventors: DESIE GUIDO, LEMMENS LUC, VERSCHUEREN ERIC, DESIE, GUIDO, LEMMENS, LUC, VERSCHUEREN, ERIC, DESIE, GUIDO, C/O AGFA-GEVAERT N.V., LEMMENS, LUC, C/O AGFA-GEVAERT N.V., VERSCHUEREN, ERIC, C/O AGFA-GEVAERT N.V.
Applicants: AGFA GEVAERT NV, AGFA-GEVAERT NAAMLOZE VENNOOTSCHAP
Application year: 1992
Main classification: B41M5
IPC codes: B41M5