MXPA97010507A - Ink receptor sheet for printing with it chorrode - Google Patents

Abstract

The present invention relates to a coated substrate comprising: a first layer substrate having the first and second surfaces, a second layer coating that lies on the first surface of the first layer substrate, the second layer coating of which is composed of: from about 25 to about 70 percent by weight of a latex hinder, from about 25 to about 65 percent by weight of a hydrophilic silica having an average particle size of less than about 20 microns and a pore volume greater than 0.4 cc / g, from about 1 to about 20 percent by weight of a latent base, and from about 1 to about 4 percent by weight of a viscosity modifier of water-soluble polyacrylate, all based on the total dry weight of the second layer, and a third layer coating that lies on the second layer coating, whose third layer coating is composed or a water soluble cationic polymer

Description

INK RECEPTOR SHEET FOR PRINTING WITH INK JET Background of the Invention The present invention relates to a coated substrate.

The inkjet printing method is a commercially important fast-growing printing process due to its ability to produce multiple-color, high-quality and economical prints. Inkjet printing has become the method of choice for producing hard colored copies of computer-generated images consisting of graphs and smelters in both narrow and broad formats.

In general, the ink used in ink jet printing consists of an aqueous dye solution, of ur. humectant, and of a pH buffer. These formulations are desirably due to their low cost, availability, safety and environmental friendliness. In ink jet printing, uniformly shaped droplets of the aqueous formula are ejected from a nozzle as very small droplets onto a printing substrate. The printing substrate should allow printing of well-formed round points of high optical density. The substrate must control the feathering (spreading) of the ink droplets and absorb the ink vehicle quickly (fast drying time) while the dye is absorbed on the surface to give sharp high density prints. Ideally, the substrate should also "fix" the dyes (for example, make them "insoluble in water") to make the printing resistant to moisture and water, but practically, it is very important to obtain all the above-mentioned properties in an inkjet printing substrate.

There are a large number of references that refer to inkjet printable substrates. The typical substrate is a paper or other material that has an ink-receiving coating. The coating typically includes one or more pigments and a binder. The pigments that have been used, alone or in combination, include, by way of illustration only, silica; clay, calcium carbonate; talcum, barium sulfate, diatomaceous earth; titanium dioxide, non-spherical colloidal silica modified with cation, in which the modifying agent is aluminum oxide, hydrozirconium oxide, or hydrostrain oxide; the silica composed of calcium carbonate; prismatic orthohombic argonite calcium carbonate; alumina; Aluminum silicate; calcium silicate; kaolin, magnesium silicate, magnesium oxalate, calcium-magnesium carbonate; magnesium oxide; magnesium hydroxide; high swollen montmorillonite clay; amorphous silica particles having a coating of a Group II metal; synthetic silica; and silica micropolvo. In some cases, the pigment may have certain defined requirements, such as a particle diameter, oil absorption, surface areas, water absorption, refractive index, and water solubility.

Several binders have been used to form the ink receptive coating. Examples of such binders include again by way of illustration only, a mixture of the water-insoluble cationic polymer and esterified starch; an epoxy resin and a thermoplastic resin; acrylic resins and other water-soluble polymers; a mixture of an alkyl-quaternary ammonium (meth) acrylate polymer and an alkyl-quaternary ammonium (meth) acrylamide polymer; poly (vinyl alcohol); a mixture of acrylic resin and polyvinyl alcohol; vinyl acetate-vinylpyrrolidone copolymer or polyvinylpyrrolidone or a mixture thereof; and an amine salt of a carboxylated acrylic resin; oxidized or esterified starch; derivatized cellulose; casein; jelly; soybean protein; maleic anhydride-styrene resin or a derivative thereof; styrene-butadiene latex, - and poly (vinyl acetate).

Additional materials have been included in the ink receptive layer, such as a cationic polymer. In addition, two or more layers have been used to form the ink receptive coating.

Despite the large number of improvements to inkjet printing substrates, there is not yet a single substrate which satisfactorily produces sharp images of bright color without feathers and which do not bleed when exposed to moisture or water. Therefore, there is an opportunity for an improved substrate for ink jet printing that has been developed to overcome the above disadvantages.

Synthesis of the Invention The present invention relates to some of the difficulties and problems discussed above by providing an inkjet printable coated substrate which is particularly useful with colored water-based inkjet inks. The coated substrate of the present invention gives sharp prints of bright color without featheredness. In addition, printed images will not bleed when exposed to moisture or water.

The coated substrate of the present invention includes a first, a second and a third layer. The first layer has the first and second surfaces. For example, the first layer may be a film or a non-woven fabric. Desirably, the first layer will be a cellulosic nonwoven fabric. The second layer will cover the first surface of the first layer. The second layer is composed of from about 25 to about 70 percent by weight of a latex binder, from about 25 to about 65 percent by weight of the hydrophilic silica, from about 1 to about 20 percent by weight of a latent base, and from about 1 to about 4 percent by weight of a water soluble viscosity modifier, in which all percent by weight are based on the total dry weight of the second layer. The third layer covers the second layer and is composed of a cationic polymer soluble in water.

In general, the hydrophilic silica will have an average particle size no greater than about 20 microns. For example, hydrophilic silica will typically have an average particle size of from about 1 to about 20 microns. In addition, hydrophilic silica will generally have a pore volume greater than 0.4 cubic centimeters per gram (cc / g). As an example, the pore volume of the hydrophilic silica can be from about 1 to about 2 cc / g.

The latent base is a di- or trivalent metal compound which has a limited solubility in which and which is capable of reacting with a carboxylic acid to form an insoluble carboxylic acid salt. The latent base will generally have a solubility product in water at 25 ° C or less of about 10"5. For example, the latent base may have a product solubility in water of about 10" 8 or less. The latent base may be an alkaline earth metal salt, such as calcium carbonate.

If desired, a fourth layer can cover the second surface of the first layer. For example, such a layer may be what is often mentioned in the art of papermaking as a layer of later size. As another example, the fourth layer can be a tied layer, for example, a coating designed to attach a pressure sensitive adhesive to a second surface of the second layer. Alternatively, the fourth layer itself can be a pressure sensitive adhesive. When the fourth layer is a tied layer, the sixth layer consisting of a pressure sensitive adhesive and covering the third layer may also be present.

In addition, a fifth layer may be present between the first surface of the first layer and the second layer. An example of such a layer is what is known in the art of papermaking as a barrier layer.

Detailed description of the invention As used herein, the term "non-woven fabric" is intended to include any non-woven fabric, including those prepared by such processes as melt extrusion as meltblowing, of coformación and of union with spinning. The term also includes non-woven fabrics prepared by air placement or wet placement of relatively short fibers to form a fabric or sheet. Thus, the term includes non-woven fabrics prepared from the supply for making paper. Such a supply may include only cellulose fibers, a mixture of cellulose fibers and synthetic fibers, or only synthetic fibers. When the supply contains only cellulose fibers or a mixture of cellulose fibers and synthetic fibers, the resulting fabric is referred to herein as a "cellulosic nonwoven fabric". Of course, the paper may also contain adhesives and other materials, such as fillers, for example, clay and titanium dioxide, as is well known in the art of making paper.

The term "latex binder" is used herein to mean a dispersion of polymer particles insoluble in water, in water. The term "polymer" is intended to encompass both homopolymers and copolymers. The copolymers can be random, graft block or alternating polymers of two or more monomers. The polymer is typically a film-forming polymer, such as, by way of illustration only, of polyacrylates, styrene-butadiene copolymers, vinyl acetate-ethylene copolymers, nitrile rubbers, polyvinyl chloride, poly (vinyl acetate) ), ethylene-acrylate copolymers and acrylate-vinyl acetate copolymers. Binders are well known to those having ordinary skill in the art.

The term "hydrophilic silica" is used herein to mean any amorphous, hygroscopic silica having a hydrophilic surface. The hydrophilic surface may be the characteristic of the natural hydrophilic surface of the silica. For example, the silica may be a fumed silica or a precipitated silica. The silica surface can be modified, if desired, as long as the modifying agent is hydrophilic. As another example, silica can be silica that occurs naturally, such as diatomaceous earth. An example of diatomaceous earth silica is Celite® 321 (from Manville Products Corporation, of Denver, Colorado). In general, the average particle size of the silica will not be greater than about 20 microns. As a practical matter, the average particle size of the silica will typically be in the range of from about 1 to about 20 microns. For example, the average particle size can be from about 2 to about 13 microns. As another example, the average particle size can be from about 3 to about 9 microns.

In addition, the hydrophilic silica will generally have a pore volume greater than 0.4 cc / g. For example, the hydrophilic silica can have a pore volume of from about 1 to about 2 cc / g. As another example, the hydrophilic silica can have a pore volume of from about 1.2 to about 1.9 cc / g. As another example, the hydrophilic silica can have a pore volume of from about 1.2 to about 1.7 cc / g.

As used herein, the term "latent base" is meant to mean a di- or trivalent metal compound which has a limited solubility in water and which is capable of reacting with the carboxylic acid to form an insoluble carboxylic acid salt. . The term "limited solubility in water" means that the compound has a product of solubility in water at 25 ° C of less than about 10"5. For example, the latent base may have a solubility of product in water of about 10. "ß or less. Examples of the latent bases include, without limitation, calcium carbonate, calcium oxalate, zinc carbonate, zinc oxalate, aluminum carbonate, and aluminum hydroxide. Desirably, the latent base will be an alkaline earth metal salt. More desirably, the latent base will be calcium carbonate.

The term "viscosity modifier" is used herein to mean a polymer containing carboxylic acid functional groups, which upon neutralization with an alkaline material, cause the polymer chains to either dissolve or swell. Without wishing to be bound by a theory, it is believed, that in an alkaline environment, the polymer chains unwind. The highly extended polymer molecules increase the viscosity of the ink by interacting with the water in the ink formula. Typical viscosity modifiers are acrylic emulsions.

As used herein, the term "cationic polymer" is intended to include any cationic functional groups containing water-insoluble polymer. For example, the cationic polymer can be an amide-epichlorohydrin polymer. A polyacrylamide with cationic functional groups, polyethylene imine, polydiallylamine, a synthetic organic polycationic quaternary polymer or the like.

The coated substrate of the present invention includes a first, a second and a third layer. The first layer has the first and second surfaces. For example, the first layer may be a film or a non-woven fabric.

Desirably, the first layer will be a cellulosic nonwoven fabric. For example, the first layer may be a polymer-reinforced paper, sometimes referred to as a paper impregnated with latex. As another example, the first layer may be a bonded paper, for example, a paper composed of wood pulp fibers and cotton fibers. The basis weight of the first layer will typically vary from about 40 to about 300 grams per square meter (gsm). For example, the basis weight of the first layer can be from about 50 to about 250 grams per square meter. As a further example, the basis weight of the first layer can be from about 50 to about 200 grams per square meter.

The second layer covers the first surface of the first layer. The second layer is composed of from about 25 to about 70 percent by weight of the latex binder, from about 25 to about 65 percent by weight of a hydrophilic silica, from about 1 to about 20 percent by weight of a latent base, and from about 1 to about 4 percent by weight of a water-soluble viscosity modifier, in which all percents by weight are based on the total dry weight of the second layer.

By way of example, the amount of latex binder present in the second layer can be from about 30 to about 50 percent by weight. As another example, the amount of binder present can be from about 30 to about 40 percent by weight. Also by way of example, the amount of hydrophilic silica present in the second layer can be from about 40 to about 60 weight percent. As a further example, the amount of hydrophilic silica can be from about 45 to about 55 percent by weight.

Also by way of example, the amount of latent base in the second layer can be from about 5 to about 20 percent by weight. As a further example, the amount of water soluble viscosity modifier can be from about 1.5 to about 3.5 percent by weight.

The thickness of the second layer will typically be in a range of from about 10 to about 50 microns. For example, the thickness of the second layer can be from about 15 to about 45 micrometers. As another example, the thickness of the second layer can be from about 20 to about 40 microns.

The second layer is generally formed on the first surface of the first layer by means which are well known to those containing an ordinary skill in the art. By way of illustration only, the layer can be formed by doctor blade; air blade; Meyer rod; roller; Reverse roller; and gravure coatings, brush applicator; or spray. The second layer will typically be formed from a dispersion. The dispersion will have a viscosity of from about 0.005 to about 1 Pa s (5 to 1,000 centipoise) as measured with a Brookfield Viscometer, Model LTV, using a No. 2 spindle at 30 rpm (Brookfield Engineering Laboratories, Inc., from Stoughton, Massachusetts). For example, the dispersion may have a viscosity of from about 0.01 to about 0.5 Pa s (10 to 500 centipoise). As a further example, the dispersion can have a viscosity of from about 0.03 to about 0.25 Pa s (30 to 250 centipoise).

The third layer covers the second layer and is composed of a cationic polymer soluble in water. The cationic polymer can be, for example, a polymer of anudeepichlorohydrin, polyacrylamides with cationic functional groups, polyethylene imines, polyethylamines, and the like. The layer is typically formed of an aqueous solution of the cationic polymer. Another solution can be formed from any of the processes described above for the formation of the second layer.

In some embodiments, a fourth layer may be present; such a layer will cover the second surface of the first layer. The layer may be, by way of illustration, a coating of later size. Such a coating generally consists of a binder and clay. For example, the binder may be a polyacrylate, such as Rhoplex HA-16 (from Rohm and Haas Company, of Philadelphia, Pennsylvania). For another example, clay can be Ultra Hite 90 (from Englehard, Charlotte, North Carolina). A typical formula will include the two materials in amounts of 579.7 parts by weight and 228.6 parts by weight, respectively. The water and / or a thickener will be added as necessary to give a final dispersion viscosity in the range of 0.100-0.140 Pa s (100-14C centipoise) at room temperature.

Also by way of illustration, the fourth layer may be a tied layer, for example, a coating designed to attach a pressure sensitive adhesive to the second surface of the first layer. A typical attached coating consists of a polyacrylate binder, clay and silica. Alternatively, the fourth layer itself may be a pressure sensitive adhesive. For example, a layer of pressure-sensitive adhesive may consist of a styrene-butadiene copolymer, a poly (vinyl acetate) or a natural rubber. A layer of pressure sensitive adhesive will typically be present at a basis weight of from about 10 to about 40 grams per square meter. When the fourth layer is a bonded layer, a sixth layer consisting of a pressure sensitive adhesive and covering the fourth layer may also be present.

In addition to or instead of the fourth layer, a fifth layer may be present. The fifth layer is usually located between the first and second layers. The fifth layer will typically be formed from a dispersion consisting of, by way of example only, 208 parts by weight of Hycar® 26084 (B. F.

Goodrich company, of Cleveland, Ohio), a polyacrylate dispersion having a solids content of 50 percent by weight (104 parts by dry weight), 580 parts by weight of a clay dispersion having a solids content of 69 percent by weight (400 parts by dry weight) and 100 parts by weight of water. Additional water and / or thickener can be added as necessary to give a final dispersion viscosity in the range of 0.100-0-140 Pa s (100-140 centipoise) at room temperature.

The present invention is further described by the following examples. Such examples, however, should not be considered as limiting, in any way, either of the spirit or of the scope of the present invention.

In the examples, all inkjet print evaluations were made using a Desk Jet 550 C color inkjet printer, model C2121A, from Hewlett Packard Company, Camas, Washington. Three different test patterns were used to evaluate the print sharpness, the ink drying rate, the color brightness and the water resistance of the printed image. The first test pattern consisted of black foundries and a large solid printed "C". The black castings were used to evaluate the sharpness and the featheredness of the fabric. The large solid printed "C" was used to evaluate the ink coverage and the evenness of the application. It was also used to evaluate drying times and resistance to water and moisture of the various coating compositions. A series of multiple colors of printed bars and multi-color graphics ("happy birthday") were used to evaluate the color brilliance, featheredness, and water resistance of colored inkjet inks.

Example 1 A synthetic printed polypropylene paper, Kimdura® FPG-110 Synthetic Printing Paper from Kimberly-Clark Corporation, of Roswell, Georgia, was used as the base substrate or as the first layer. One side of the synthesized paper was coated with a composition consisting of 48 weight percent (75 parts by weight) of a silica having an average size of 7.5 microns (Syloid 74X35000, from WR Grace Company, of Valtimore, Maryland), 16 percent by weight (25 parts by weight) of calcium carbonate (M-60, Mississippi Lime Company, of Alton, Illinois); 32 percent by weight (5C parts by weight) of latex binder (Hycar® 26084, a polyacrylate available from BF Goodrich Company, of Cleveland, Ohio, and 3 weight percent (5 parts by weight) of ur modifier. viscosity (Acrysol-ASE-95NP, a rheology modifier of polyadrylic acid available from Rohm and Haae Company, of Philadelphia, Pennsylvania.) The coating was applied to a basis weight of 15 grams per square meter (gsm) using a Meyer rod and formed the second layer when dried in a forced air oven at 95oC (a Blue M Electric Stabil-Therm furnace, from General Signal Company, of Blue Island, Illinois).

After drying the second layer was overcoated with 6.8 percent by weight of an aqueous solution of a cationic polymer, an amine-epichlorohydrin copolymer (Reten 2404LS supplied by Hercules, Inc., of Wilmington, Delaware) using a Meyer No rod. 6. Because the amount of cationic polymer applied was very small, the basis weight of the coating of the third layer was not determined. The third layer was dried, described above for the second layer.

The resulting coated substrate was printed with the three test patterns described above to give clear, clear, (without plumage) graphic images and fused with bright colors which did not mix when exposed to moisture and water. Image quality and featheredness were judged visually. Moisture and water resistance were tested by placing drops of water on the various colors of the printed image, waiting for approximately 10 seconds, and then cleaning with a facial tissue. The black, cyan and yellow inks were very resistant to water and none of these was washed on the tissue. The magenta ink bled to a small degree, with a small red smear evident on the tissue. The printed sheet was also kept under running water from a faucet for approximately 30 seconds without bleeding from the black, cyan and yellow inks. A small amount of the magenta ink bled to the surrounding coating under this condition.

Example 2 Silica is commercially available in many different particle sizes, pore volumes and oil absorption capacities. Therefore, in order to evaluate a number of such silicas, the procedure of Example 1 was repeated, except that the viscosity modifier was replaced with 1.6 percent by weight, based on the total weight of the second layer, of Acrysol ASE 60 (a polyacrylic acid rheology modifier available from Rohm and Hass Company, Philadelphia Pennsylvania) and then 10 different silicas were used in many assays. One silica per test. The silica-studied were as follows: Silica A Silica A was Syloid 244 (from W. R. Grace Company, of Baltimore, Maryland). The material was reported as com; having an average particle size of 3 microns and a pore volume of 1.4 cubic centimeters per gram (cc / g).

Silica B This silica was Syloid 74X3500, the silica used in Example 1. The material is reported as having an average particle size of 7.5 microns and a pore volume of 1.2 cc / g.

Silica C Silica C was Mizukasil P-78A (Mizusawa Industrial Chemicals Ltd, from Japan, available from Performance Chemicals Inc., DePere, Wisconsin). The material was reported as having an average particle size of 3.5 micrometers and a pore volume of 1.5 cc / g.

Silica D Silica D was Syloid AL-1 (W. P. Grace Company, of Baltimore, Maryland). The material was reported as having an average particle size of 7 micrometers and a pore volume of 0.4 cc / g.

Silica E Silica E was Syloid 74X6500 (W. R. Grace Company, of Baltimore, Maryland). The material is reported having an average particle size of 3.5 micrometers and a pore volume of 1.2 cc / g.

Silica P This silica was Syloid 74 (W. R. Grace Company of Baltimore, Maryland). The material was reported as having ur. particle size of from 6 micrometers and a volume of porc of 1.2 cc / g.

Silica G Silica G was Mizukasil P-78F (Mizusawa Industrial Chemicals Ltd, of Japan, available from Performance Chemicals Inc., DePere, Wisconsin). The material was reported as having an average particle size of 13 micrometers and ur. pore volume of 1.7 cc / g.

Silica H This silica was Mizukasil P-78D (Mizusawa Industrial Chemicals Ltd., of Japan, available from Performance Chemicals Inc., DePere, Wisconsin). The material was reported as having an average particle size of 8 micrometers and a pore volume of 1.6 cc / g.

Silica I Silica I was Dev A SMr-670 (W. R. Grace Company, of Baltimore, Maryland). The material was reported as having an average particle size of 9 micrometers and a pore volume of 1.9 cc / g.

Silica J This silica was W500 (W. R. Grace Company, of Baltimore, Maryland). This material was reported as having an average particle size of 5 micrometers and a pore volume of 1.5 cc / g.

The results of the ten trials are summarized er. Table 1. In the table, the "average size" column is the average particle size reported in micrometers and the "pore volume" column is the reported pore volume ei cc / g.

TABLE 1 SUMMARY OF TESTS WITH DIFFERENT SILICONES SIZE VOLUME EVALUATION OF SESSION LICE AVERAGE PORO PRINTING 2-1 A 3.0 1.4 Adequate 2-2 B 7.5 1.2 Very good 2-3 C 3.5 1.5 Adequate 2-4 D 7.0 0.4 Poor 2-5 E 3.5 1.2 Adequate 2-6 F 6.0 1.2 Good 2-7 G 13.0 1.7 Adequate 2-8 H 8.0 1.6 Good 2-9 I 9.0 1.9 Adequate 2-10 J 5.0 1.5 Very good The data in Table 1 suggest that silica particle size and pore volume are important for clear and sharp images with inkjet printing. Coatings made with silica pigments having particle size between 5 and around E micrometers and pore volumes greater than 0.4 cc / g gave the best printing results. Note that the poor results were achieved with a silica having a pore volume of 0.4 cc / g, even though the average particle size was 7.0 micrometers (see tests 2-4).

The larger particular size silica pigments typically resulted in poorer print quality and a sheet which is rough to the touch; see, for example, tests 2-7. Conversely, the use of silica pigments with smaller particle sizes gave a soft feeling sheet, but only adequate print quality. See, for example, tests 2-3.

EXAMPLE 3 A number of clock modifiers were investigated as ink viscosity modifiers to control the featheredness of the ink. The high molecular weight poly (oxyethylenes) were not satisfactory because they immediately converted the coating compositions containing silica to a putty type consistency. Cellulose gums, such as methyl cellulose and hydroxyethyl cellulose, were tested but did not satisfactorily stop the ink feathered.

The ink viscosity modifiers which controlled the best ink flushing were the polyacrylic acid clock modifiers, for example, the Acrisol polymers from Rohm & Haas Company of Philadelphia, Pennsylvavia. Therefore, the Acrisol ASE-60, ASE-75, and ASE-95NP were evaluated over a range of concentrations of about 1.6% by weight to about 3.8% by weight, based on the total weight of the coating or the second cap. For convenience, such viscosity modifiers will be mentioned herein. forward as modifiers A, B, and C.

The viscosity modifiers were evaluated by repeating EXAMPLE 1, and varying the viscosity modifier and / c the concentration of viscosity modifier in the composition. That is, 10 parts by weight of silica, calcium carbonate and binder were maintained in each test at 75, 25 and 50, respectively. The results are summarized in Table 2. Er. the columns of "muddy" (for smearing) and "discolored" (for discoloration) under the heading "water resistance", "S" represents "light" and "VS" represents "very light".

TABLE 2 SUMMARY OF TESTS WITH DIFFERENT TYPES AND LEVELS OF VISCOSITY MODIFIERS VISCOSITY MODIFIER EVALUATION WATER RESISTANCE TEST TYPE PARTS PORTION OF PRINTED EMBARRATED DECOLORED 3-1 A 2.5 1.6 GOOD S NONE 3-2 A 3.0 2.0 VERY GOOD VS S 3-3 A 3.5 2.3 GOOD S NONE 3-4 B 2.5 1.6 POOR NONE NONE 3-5 B 3.0 2.0 SUITABLE NONE NONE 3-6 B 3.5 2.3 POOR S NONE 3-7 B 4.0 2.6 GOOD VS NONE 3-8 B 5.0 3.2 POOR VS NONE 3-9 C 2.5 1.6 SUITABLE S NONE 3-10 C 3.0 2.0 GOOD VS NONE 3-11 C 3.5 2.3 VERY GOOD S NONE 3-12 C 4.0 2.6 EXCELLENT VS NONE 3-13 C 5.0 3.2 EXCELLENT S NONE 3-14 C 6.0 3.8 EXCELLENT S NONE As shown in Table 2, all three viscosity modifiers gave at least a good control of the ink feathered at least one concentration. He Acrisol ASE-95Np at 3.8% by weight gave the best results, as illustrated by Example 1.

EXAMPLE 4 The choice of base used to form the carboxylate salt of the polyacrylic acid modifier had a dramatic effect on the featheredness control and the water resistance of the inkjet inks. The procedure of Example 1 was repeated, except that the second layer consisted of a mixture of silica A (Siyloid 244 from W. R. Grace Company), a latex polyacrylate binder (Hycar 26084 from B. F. Goodrich Company) and base. The parts by weight on a dry weight basis of silica and latex binder in each case were 100 and 50, respectively. In each case, the third layer was formed on the second layer as described in Example 1.

For test 4-1, 6.3% by weight of modifier A of the Example 3, a polyacrylic acid clock modifier (Acrisol ASE-60 from Rohm &Haas Company) was included in the second layer. No base was added. The printed sheets gave an unacceptable flushing of the inks.

In Test 4-2, 2.0% by weight of Acrisol ASE-60 was included and the pH of the resulting coating mixture was raised to 8.0 with a sodium hydroxide solution. This leaf gave a clear and clear impression without feathered. However, the water resistance of the inks was unacceptable on this sheet.

In trial 4-3, 2.3% by weight of Acrisol ASE-60 was included in the second layer; the pH of the resulting latex mixture was raised to 8.6 with an ammonium hydroxide solution. This sheet gave an unacceptable ink feathered. The results were the same as with trial 4-1. It is believed that the amount of ammonium hydroxide was driven out of the coating during drying. Consequently, the viscosity modifier of polyacrylic acid did not remain in the carboxylate salt or in the thickened form upon drying of the coating.

Finally, in Test 4-4, 1.8% by weight of Acrisol ASE-60 and 16% by weight of calcium carbonate, a latent and water-soluble base, were added to the second layer coating composition. The sheets coated with this composition gave clear and clear impressions with good water resistance. The calcium carbonate apparently reacted slowly with the carboxylic acid groups of the viscosity modifier (the pH was increased from 6 to 8) to form the water-insoluble calcium carboxylate salt groups which controlled the feathered and did not interfere with the insolubility of the dyes.

EXAMPLE 5 The level of latex binder used in the base layer is important to obtain a clear and clear print and to effectively bond the coating to the base substrate. If very little latex binder is used the coating binds poorly to the substrate or to the first layer. If too much latex is used the coating becomes non-porous and will not quickly absorb water in the ink, resulting in poor print quality. Therefore, the experiments were conducted to determine the effects of the variation of the level of latex binder in the second layer from about 33% by weight to about 67% by weight, based on the total weight of the second layer. . In each case, the silica and latex binder were the same as those employed in Example 1. The results are summarized in Table 3 which includes the results of the Denninson Wax Pick method.

In addition to the ink jet printer test described in Example 1, the coated substrates were evaluated by the Denninson Wax Pick method, ASTM method D2482-66T, from Dennison Standard Paper Testing Waxes series 39-330. Such waxes are designated with graduated degrees of adhesion, with the lower numbers having a low adhesion and the higher numbers having superior adhesion. Therefore, the coating that you "take" with a higher number of coating stronger with respect to the coating adhesive force.

TABLE 3 SUMMARY OF PROPORTION OF SILICA AND AGGLUTINANT TOMA EVALUATION PARTS OF PARTS OF PERCENT OF DE TEST AGGLUTINANT AGGLUTINANT SILK PRINTING WAX -1 100 50 33 GOOD 6 5-2 100 75 43 POOR 9 5-3 75 75 50 POOR 10 5-4 100 100 50 POOR 9 5-5 50 100 67 POOR 10 The table shows that the use of 33% by weight of latex binder, based on the total coating weight, gave the best balance of printing properties and coating bonding of the second layer to the substrate or to the first layer.

EXAMPLE 6 The amount of cationic polymer added as the third layer was too small to be measurable by weight differences, but it is still important to obtain a good water resistance of the inkjet inks. If a third layer of cationic polymer is not used, the inks can be removed from the second layer with water. When the third layer consisted of a solution of 4.9% by weight of 204LS retainer applied with a Meyer No. 6 rod, the water resistance was greatly improved compared to the absence of the third layer, but the inks still bled when the drops of water were applied to the printed surface and then cleaned with a facial tissue. The use of 6.8% by weight of 204LS retainer solution, described in EXAMPLE 1 resulted in good water resistance.

Even though the descriptions have been made in detail with respect to the specific modalities thereof, it will be appreciated by those skilled in the art upon achieving an understanding of the foregoing that alterations, variations and equivalents of these modalities can easily be conceived. Therefore, the scope of the present invention will be established as that of the attached clauses and any equivalents thereof.

Claims (17)

1. A coated substrate comprising: A first layer having the first and second surfaces; A second layer covering the first surface of the first layer, whose second layer is composed of: an effective amount of a latex binder; an effective amount of a hydrophilic silica; an effective amount of a latent base; Y an effective amount of a water soluble viscosity modifier; Y A third layer covering the second layer, whose third layer is composed of a cationic polymer soluble in water.

2. The coated substrate as claimed in Clause 1, characterized in that the amount of latex binder in the second layer is from about 25 to about 70% by weight, based on the total weight of the second layer.

3. The coated substrate as claimed in Clause 2, characterized in that the amount of latex binder in the second layer is from about 3 C to about 50% by weight.

4. The coated substrate as claimed in Clause 1, characterized in that the amount of hydrophilic silica in the second layer is from about 25 to about 65% by weight, based on the total dry weight of the second layer.

5. The coated substrate as claimed in Clause 4, characterized in that the amount of hydrophilic silica in the second layer is from about 4C to about 60% by weight.

6. The coated substrate as claimed in Clause 1, characterized in that the hydrophilic silica has an average particle size of less than about 20 micrometers.

7. The coated substrate as claimed in Clause 6, characterized in that the hydrophilic silica has an average particle size of from about 1 to about 20 micrometers.

8. The coated substrate as claimed in Clause 6, characterized in that the hydrophilic silica has an average particle size of from about 8 to about 13 micrometers.

9. The coated substrate as claimed in Clause 1, characterized in that the amount of latent base in the second layer is from about 1 to about 20% by weight, based on the total dry weight of the second layer.

10. The coated substrate as claimed in Clause 9, characterized in that the amount of latent base in the second layer is from about 5 to about 20% by weight, based on the total dry weight of the second layer.

11. The coated substrate as claimed in Clause 1, characterized in that the amount of water-soluble viscosity modifier in the second layer is from about 1 to about 4% by weight, based on the total dry weight of the Second layer.

12. The coated substrate as claimed in Clause 11, characterized in that the amount of viscosity modifier in the second layer is from about 1.5 to about 3.5% by weight.

13. The coated substrate as claimed in Clause 1, characterized in that the latent base is an alkaline earth metal salt.

14. The coated substrate as claimed in Clause 13, characterized in that the latent base is calcium carbonate.

15. The coated substrate as claimed in Clause 1, characterized in that the viscosity modifier is a polyacrylate.

16. The coated substrate as claimed in Clause 1, characterized in that the first layer is a film or a non-woven fabric.

17. The coated substrate as claimed in Clause 16, characterized in that the first layer is a cellulosic nonwoven fabric.