KR100420196B1 - Ink-receptive absorbent coating - Google Patents

Abstract

The present invention relates to a rapidly drying ink-repellant coating suitable for use on an ink-repellant sheet comprising a mixture of one or more hydrophilic liquid-absorbing polymers and a polyethylene-acrylic acid copolymer having at least 10% acrylic acid, May be used alone or as part of a coating system comprising an upper layer that improves dry heat properties.

Description

INK-RECEPTIVE ABSORBENT COATING [0002]

BACKGROUND OF THE INVENTION Imaging devices, such as inkjet printers and pen plotters, are well known for use in methods of printing various information including labels and multicolored graphics. In order to display this information, there is a need for transparent ink-soluble, imageable receptors which are used as overlay of technical drawings and as transparent paper for overhead projection. Imaging with an inkjet printer or pen plotter involves depositing ink on the surface of such a transparent receptor. These image forming apparatuses usually use inks which can be kept exposed to air for a long period without being dried.

Even after absorbing a considerable amount of liquid immediately after image formation, it is desirable that the surface of such a receptacle has a dry feeling and non-tackiness when touched. Therefore, a transparent material capable of absorbing a considerable amount of liquid while maintaining a certain degree of durability and transparency Are useful as imageable receptors for forming images.

The liquid absorbent materials disclosed in U.S. Patents 5,134,198, 5,192,617, 5,219,928 and 5,241,006 were intended to improve drying and shorten the drying time. Such materials include cross-linked polymer compositions capable of forming a continuous matrix for a liquid-absorbent, semi-interpenetrating polymer network. Such a network is a polymeric mixture in which one or more of the polymer components after crosslinking is crosslinked to form a continuous network throughout the material and the uncrosslinked polymer components are entangled with one another to form a macroscopically homogeneous composition to be. Such a composition is useful for producing durable ink absorbing transparent graphic materials.

WO 8806532 (AM International) discloses a recording clear paper and its aqueous preparation process. This transparent photo paper is coated with a hydroxyethyl cellulose polymer or a polymer blend. The coating solution may contain a surfactant that promotes adhesion and uniformity to the surface and hydrated alumina to impart a pencil tooth to the surface.

U.S. Patent No. 5,120,601 (Asahi) discloses a recording sheet comprising an ink receiving layer containing superabsorbent resin particles of 1 to 100 μm and a binder. The resin particles protrude from the surface of the binder layer at a height of 1 占 퐉 or more and include 50 to 5,000 per 1 mm2. The resin particles include sodium, lithium, and potassium polyacrylate; Vinyl alcohol / acrylamide copolymers; Sodium acrylate / acrylamide copolymer; Cellulose polymers; Starch polymers; Isobutylene / maleic anhydride copolymer; Vinyl alcohol / acrylic acid copolymer; Polyethylene oxide modified product; Dimethyl ammonium polydiallylate; And quaternary ammonium polyacrylate. Useful binders include any hydrophilic resins such as starch, gelatin, cellulose, polyethyleneimine, polyacrylamide, polyvinylpyrrolidone, polyvinyl alcohol, polyester, sodium polyacrylate, polyethylene oxide, poly-2-hydroxyethyl Methacrylates, cross-linked hydrophilic polymers, hydrophilic water-soluble polymer complexes, and the like.

U.S. Patent No. 4,636,805 (Canon) discloses a recording medium comprising an ink receiving layer capable of fixing ink within 3 minutes at a rate of 0.7 ㎕ / cm 2 at 20 캜 and 65% RH. In one embodiment, it includes hydroxyethyl cellulose. Such patents include, for example, various gelatins; Polyvinyl alcohol; Starch; Cellulose derivatives; Polyvinylpyrrolidone; Polyethylene imine; Polyvinylpyridium halide; Sodium polyacrylate, SBR and NBR latex; Polyvinylformal; PMMA; Polyvinyl butyral; Polyacrylonitrile; Polyvinyl chloride; Polyvinyl acetate; Other materials such as phenolic resins are disclosed.

U.S. Patent No. 4,701,837 (Canon) discloses a light-transmitting recording medium having an ink receiving layer formed mainly of a water-soluble polymer and a crosslinking agent. The crosslinked polymer has a degree of crosslinking that satisfies the water resistance of the receptive layer while imparting an ink receptivity of 0.2 占 / / cm < 2 > to the receptive layer. Water-soluble polymers include natural polymers such as gelatin, casein, starch, gum arabic, sodium monoallylate, hydroxyethylcellulose, carboxyethylcellulose, or modified products of these polymers; Polyvinyl alcohol; Fully or partially saponified products of vinyl acetate and other monomers; (Meth) acrylic acid, maleic acid, crotonic acid, and the like, with other monomers or copolymers of unsaturated carboxylic acids; Copolymers or homopolymers of sulfonated vinyl monomers such as vinyl sulfonic acid, sulfonated styrene, and the like with other vinyl monomers; A copolymer or homopolymer of (meth) acrylamide with other vinyl monomers; Copolymers or homopolymers of ethylene oxide with other vinyl monomers; Terminated polyurethanes having blocked isocyanate groups; A polyamide having a group as defined above; Polyethylene imine; Polyurethane; Polyester, and the like.

U.S. Patent No. 5,277,965 (Xerox) discloses a recording medium comprising a base sheet having an ink receiving layer on one side and a heat absorbing layer on the other side and an anti-curl layer coated on the surface of the heat absorbing layer. . Materials suitable for the ink receiving layer include, but are not limited to, hydroxypropylmethylcellulose (Methocel), hydroxyethylcellulose; Water-soluble ethylhydroxyethylcellulose; Hydroxybutyl methylcellulose, hydroxypropylcellulose, methylcellulose, hydroxyethylmethylcellulose; Vinyl methyl ether / maleic acid copolymer; Acrylamide / acrylic acid copolymer; Salts of carboxymethylhydroxyethylcellulose; Cellulose acetate; Cellulose acetate hydrogen phthalate, hydroxypropyl methylcellulose phthalate; Cellulose sulfate; PVA; PVP; Vinyl alcohol / vinyl acetate copolymer, and the like, and a binary mixture of polyethylene oxide.

U.S. Patent No. 5,118,570 (Xerox) discloses a clear photo paper comprising a hydrophilic coating and a plasticizer. The plasticizer may be selected from the group consisting of acid anhydrides, glycerol, glycols, substituted glycerol, pyrrolidinones, alkylene carbonates, sulfolanes and stearic acid derivatives. In one particular aspect of the moisture resistant inkjet transparency paper, the coating consists of a ternary mixture of hydroxypropyl cellulose, carboxymethyl cellulose, and polyethylene oxide and a plasticizer. Additives such as colloidal silica may be dispersed in the coating. Other examples include (1) hydroxypropyl cellulose; (2) vinyl methyl ether / maleic acid copolymer; (3) carboxymethylhydroxypropylcellulose; (4) hydroxyethyl cellulose; (5) acrylamide / acrylic acid copolymer; (6) Cellulose cell pate; (7) poly (2-acrylamido-2-methylpropane) sulfonic acid; (8) poly (vinyl alcohol); (9) poly (vinylpyrrolidone); And (10) hydroxypropylmethylcellulose. The mixture of polyethylene oxide and carboxymethylcellulose is mixed with a component selected from the group consisting of hydroxypropylmethylcellulose and hydroxypropylmethylcellulose.

U.S. Patent No. 5,068,140 (Xerox) discloses a transparent paper comprising a support substrate and a curl-resistant coating (s) below the substrate. In a specific embodiment, the clear photo paper comprises a curl-resistant coating consisting of two layers. The ink receiving layer in one embodiment is a mixture of cellulose and poly (ethylene oxide), such as poly (ethylene oxide), sodium carboxymethyl cellulose, hydroxymethyl cellulose; And (1) vinyl methyl ether / maleic acid copolymer; (2) hydroxypropyl cellulose; (3) acrylamide / acrylic acid copolymers; (4) sodium carboxymethyl hydroxyethyl cellulose; (5) hydroxyethyl cellulose; (6) water-soluble ethylhydroxyethyl cellulose; (7) Cellulose sulfate; (8) poly (vinyl alcohol); (9) polyvinylpyrrolidone; (10) poly (acrylamido 2-methylpropanesulfonic acid); (11) a copolymer of diethylenetriamine and adipic acid; (12) Quaternized poly (imidazoline); (13) poly (N, N-methyl-3-Sdimethylenepiperidinium chloride); (14) modified poly (ethyleneimine) epichlorohydrin; (15) a mixture of components selected from the group consisting of ethoxylated poly (ethyleneimine); And a mixture of poly (a-methylstyrene) with a component having a chlorinated compound.

As already disclosed, when an image is formed with an inkjet printer, a large amount of solvent (usually a mixture of glycol and water) is formed and remains in the image area. Thus, an ink-soluble coating that quickly absorbs the solvent to form an excellent image is coated on the substrate. While many of the materials disclosed above have already addressed such absorptive conditions, this condition is increased when a substantially non-absorbable transparent material is used. However, even when the absorbency is appropriate, when the dye is moved with the solvent, the solvent may diffuse into the non-image area and cause " bleeding " of the image.

U.S. Patent No. 5,342,688 addresses this bleeding problem. This patent discloses an improved ink-soluble sheet comprising a transparent substrate bearing an ink-soluble layer comprising an effective amount of a polymeric mordanting agent having at least one hydrophilic liquid-absorbing polymer and a guanidine functional group on at least one major surface thereof .

With the advent of pigmented inks, other problems have arisen when the same conventional materials are used as ink water soluble coatings. One of these problems can be characterized as a "mud-cracking" phenomenon. Apart from the theory, it is believed that the pigment used with other ink components (e.g., polymer dispersants), and possibly some dissolved components of the receptor layer, form a separate layer on the ink water soluble coating surface. Upon drying, this layer is literally splitted, cracks visible to the naked eye are formed, the image quality is poor and the optical density is low. This effect is evident in some printers that are already on the market (eg HP (registered trademark) Deskjet 1200C) and is more serious on some devices than on other devices. The present inventors have discovered an ink-soluble coating suitable for projecting an image, called a so-called " transparent photo paper ", which is coated on an ink-soluble sheet and applied to an ink deposition apparatus When the image is formed, excellent image quality can be successfully printed with a pigment-added ink.

In preferred embodiments of the present invention, the storage life is also improved when image bleeding is reduced, exposure to high temperature and high humidity, or when the solvent is prevented from flowing out of the coating (e.g., when stored in a transparent photo paper protective case) , Indicating excellent drying time.

The present invention discloses a copolymer which, when added to an ink absorption layer, can improve the drying time of the layer while imparting excellent image quality.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent material usable as an ink receiving sheet for image formation, and particularly to an improved ink receptive coating having improved image quality.

Summary of the Invention

The improved ink water soluble coating of the present invention is suitable for use on an ink water soluble sheet and includes a mixture of a hydrophilic liquid absorbent polymer, a copolymer providing rapid drying, and other additives acting together to prevent surface cracking or smearing Provides a coating that provides a high quality image that dries quickly without development.

The ink water soluble coating of the present invention comprises a polyethylene-acrylic acid copolymer and at least one hydrophilic liquid absorbent polymer. The presence of the polyethylene-acrylic acid copolymer improves the drying time of the coating while maintaining good image quality when printed with aqueous ink. The content of acrylic acid in the polyethylene-acrylic acid copolymer is preferably 10% by weight or more, more preferably 20% or more.

In one aspect, the present invention relates to a thin layer of an ink absorbent comprising a polyethylene-acrylic acid copolymer and a hydrophilic liquid absorbent polymer, and a thin upper layer which acts to improve tackiness, feed, drying time, bleed, dry heat, And an ink-soluble coating system comprising two or more layers.

In a preferred embodiment of the two-layer coating system, the bottom layer comprises a polyethylene-acrylic acid copolymer and at least one hydrophilic liquid absorbent polymer and the top layer comprises methylcellulose or hydroxypropylmethylcellulose, or mixtures thereof, having a relatively high viscosity. These ink-soluble coatings have a high drying time and, when coated on a substrate, produce excellent image quality when printed on a printer using an aqueous ink containing a pigmented ink type.

An embodiment of a highly preferred ink-soluble coating system comprises two layers, the bottom layer comprising a polyethylene-acrylic acid copolymer and polyvinylpyrrolidone,

a) a high viscosity methylcellulose binder, hydroxypropyl methylcellulose, or mixtures thereof, and

b) a salt of polyethyleneimine and a salt of substituted polyethyleneimine.

Optional ingredients such as mordants may also be present in the upper or lower layers, or both layers.

The thickness of the underlayer for a single layer coating and a two layer coating system is preferably in the range of 10 [mu] m to 40 [mu] m; In use, the thickness of the upper layer is preferably 0.5 占 퐉 to 10 占 퐉.

The terms used in this specification have the following meanings.

1. "Mud-cracking" refers to physical cracking of the image resulting in low density and low quality. This is so called because the cracks are similar to cracks that can be seen in the mud of the dry bed.

2. The terms "hydrophilic" and "hydrophilic surface" mean that the surface of the material is wettable by water, or that most of the material is capable of absorbing a significant amount of water, do. The material exhibiting surface wettability by water has a hydrophilic surface.

3. The term " hydrophilic liquid absorbing material " means a substantial amount of water, a material capable of absorbing an aqueous solution, such as a water-soluble material.

4. The terms "hydrophobic" and "hydrophobic surface" refer to materials that have surfaces that are not easily wetted by water. In the case of forming a water-insoluble polymer capable of absorbing only a very small amount of water at the time of self-polymerization, the monomer unit is referred to as hydrophobic.

5. The term " mordant " means a compound that is present in the composition to prevent diffusion in the composition by interacting with the dye.

6. The term " pigment layer " refers to a layer that is formed on the surface of a transparent photographic paper comprising a pigment, a polymeric dispersant, and various components derived from the receptive layer.

All parts, percentages, and ratios are by weight unless otherwise specified.

DETAILED DESCRIPTION OF THE INVENTION

In the ink jet printing, a large amount of liquid is generated on the image-formed surface as compared with other types of printing. The printing surface should be able to absorb all liquids and dry quickly. If the ink-soluble sheet is not dried within a few seconds or less, a favorable feeling of the consumer can not be obtained. If the drying is delayed, smearing of the image, handling problems, and the problem that the sheet can not be used immediately are caused. Also, if they are laminated or stored before being completely dried, they will stick to each other or between the sheet and the storage envelope.

The ink-soluble coating of the present invention may comprise a relatively thick single liquid absorbent layer, or a two-layer coating system with a thick underlayer and a thin top coat. When a single layer is used, its thickness is preferably in the range of 10 [mu] m to 40 [mu] m. When a two-layer coating system is used, the lower layer is preferably the same thickness as used alone, and the upper layer preferably has a thickness of 0.5 to 10 mu m.

The presence of the polyethylene-acrylic copolymer in the ink absorbing layer maintains excellent image quality and improves the drying time. The preferred copolymer has an acrylic acid content of 10% by weight or more, more preferably 20% by weight or more.

Preferred liquid absorbing hydrophilic polymer compounds for use with the polyethylene acrylic acid polymer in the lower layer of the monolayer system and the two-layer system include polyacrylamide, polyvinylpyrrolidone and modified polyvinylpyrrolidone, polyvinyl alcohol and modified poly Vinyl alcohol, and other hydrophilic and liquid absorbent polymers comprising copolymerizable monomers such as the following a) and b): < RTI ID = 0.0 >

a) vinyl lactams such as N-vinyl-2-pyrrolidone; Acrylamide, methacrylamide and their N-monoalkyl and N, N-dialkyl derivatives thereof; Alkyl-tertiary-aminoalkyl acrylates and methacrylates; Vinyl pyridine such as 2-vinyl and 4-vinyl pyridine; Preferably N-vinyl-2-pyrrolidone; Hydrophilic, water-absorbing monomers containing nitrogen selected from the group consisting of acrylamide, methacrylamide and N-monoalkyl and N, N-dialkyl derivatives thereof; And

b) hydroxyalkyl acrylates and methacrylates, wherein the alkyl groups are C ₁ -C ₅ , preferably C ₁ -C ₂ , more preferably hydroxyethyl acrylate and methacrylate; Wherein the alkyl groups are C ₁ -C ₅ , preferably C ₁ -C _2. The hydrophilic monomers are selected from the group consisting of alkyl acrylates and methacrylates, wherein the alkyl groups are C ₁ -C ₅ , preferably C ₁ -C ₂ .

A preferred material for the liquid absorbing layer is a mixture of polyvinylpyrrolidone and polyethylene-acrylic acid. The preferable polyethylene-acrylic acid content is 15 to 25% by weight of acrylic acid. The presence of a mixture of polyvinylpyrrolidone (PVP-K-90) and a polyethylene-acrylic acid copolymer (Primacor (R) 5980) having an acrylic acid content of 20% in the liquid absorbing layer improves the drying time, This is true when used in a preferred two-layer system. Improvement in drying time is observed in almost all ink jet printers.

The liquid absorbent layer may also comprise a cross-linked semi-interpenetrating network, i.e. " SIPN ". The SIPN for ink-soluble coatings can be formed from a polymer mixture comprising (a) at least one crosslinkable polyethylene-acrylic acid copolymer, (b) at least one hydrophilic liquid absorbent polymer, and (c) a crosslinking agent. SIPN is a continuous network structure in which the crosslinked polymer forms a continuous matrix. This is disclosed in U.S. Patent Nos. 5,389,723, 5,241,006, 5,376,727 and 5,208,092.

It is also preferable that an upper layer exists in addition to the liquid absorbing layer. It is applied on top of the liquid absorbent underlayer. The top layer is generally thin and comprises polymeric materials such as polyvinylpyrrolidone, polyvinyl-alcohol, modified cellulose, and mixtures thereof.

In a preferred embodiment, high viscosity modified cellulosic binders such as methylcellulose, hydroxypropylmethylcellulose, and hydroxyethylmethylcellulose and hydroxypropylmethylcellulose, and mixtures thereof, are used to optimize image quality and substantially eliminate the dry heat generated when using most pigmented inks. Is preferred.

In this embodiment, certain cellulose derivatives, including hydroxyethyl cellulose, hydroxymethyl cellulose, and carboxymethyl cellulose, are not suitable as dry heat removing binders, but these cellulose derivatives may account for less than 40% of the total cellulose content, or If dry heat is not prevalent or is not important, it may also be used as an additive. Less preferred cellulose derivatives as binders due to their hydrophobic nature, water insolubility, the need for organic solvents, and the tendency of the pigment and the pigmented inkjet ink to agglomerate include ethylcellulose, ethylhydroxyethylcellulose, and hydroxybutylcellulose. If the cellulose derivative accounts for less than 40% of the total cellulose content, it can be used again as an additive with an appropriate solvent mixture. Although hydroxypropyl cellulose is water-soluble, it is less suitable as a binder for the same reasons as the above cellulose derivatives, but can be used as an additive when it occupies less than 40% of the total cellulose content.

The top layer may also contain an organic acid salt of polyethyleneimine to further improve other properties including drying time, image staining, image whiteness and bleeding. Useful acids include dicarboxylic acid derivatives of C ₂ -C ₁₄ , phthalic acid, hydrochloric acid, boric acid and substituted sulfonic acids such as methanesulfonic acid, and p-toluenesulfonic acid is preferred. In addition, the upper layer may contain, in addition to the above-mentioned cellulose, an additive capable of improving the drying time, color, tackiness, etc. in a large amount so as not to deteriorate the dry heat performance of the pigmented ink. These additives include water soluble polymers such as polyacrylic acid, polyvinylpyrrolidone, GAF copolymer 845, polyethylene oxide, water soluble starches such as Staylok 500 and water soluble clays such as Laponite RDS, , Although these additives should account for less than 40% of the topcoat solids. Other additives may include colloidal silica, boric acid, and a surfactant.

Another additive that may be present to control curl is a plasticizer compound added to the lower layer of the film. The compound may include low molecular weight polyethylene glycols such as, for example, PEG 600 or Pycal TM 94, polypropylene glycol, or polyether.

Preferred additives for reducing ink discoloration and bleeding are mordants that can be present in the top, bottom, or both layers. When present in the upper layer or the lower layer, the amount is preferably in the range of 1 to 20 parts by weight, preferably 3 to 10 parts by weight, based on the weight of the solid content.

Useful mordants include polymeric mordants comprising at least one guanidine functional group represented by the following formula:

[ Chemical Formula 1 ]

Wherein A represents a C ₁ -C ₅ COO-alkylene group, a C ₁ -C ₅ CONH-alkylene group, COO (CH ₂ CH ₂ O) _n CH ₂ - and CONH (CH ₂ CH ₂ O) _n CH ₂ -, and n is 1 to 5;

E and D are each selected from the group consisting of C ₁ -C ₅ alkyl groups;

Or A, E, D and N are combined to form a heterocyclic compound selected from the group consisting of:

[Formula 2]

[Formula 3]

[ Chemical Formula 4 ]

[ Chemical Formula 5 ]

R ₁ and R ₂ are independently selected from the group consisting of hydrogen, phenyl, and C ₁ -C ₅ , preferably C ₁ -C ₃ alkyl,

R is selected from the group consisting of hydrogen, phenyl, benzimidazolyl and C ₁ -C ₅ , preferably C ₁ -C ₃ alkyl, y is selected from the group consisting of 0 and 1,

X ₁ and X ₂ are anions.

Feedability and anti-blocking properties can be controlled by addition of fine particles. Suitable particulates include starch, glass beads, silica, polymeric microspheres and beads, and in preferred embodiments, polymethylmethacrylate (PMMA) beads. The concentration of the fine particles is limited by the condition that, when measured according to ASTM D1003-61 (reproduced in 1979), the haze of the final coating should be transparent so as to be 15% or less. The preferable average particle diameter of the fine particle material is 5 to 40 占 퐉, and 25% or more of the particles have a diameter of 15 占 퐉 or more. Most preferably, the particle size of 50% or more of the particulate material is 20 [mu] m to 40 [mu] m. The fine particles may be added to either one or both layers, but the preferred embodiment includes fine particles in the upper layer.

Other optional ingredients may be present in the upper layer for the purpose of improving coatability, or other characteristics. Useful additives include catalysts, thickeners, adhesion promoters, glycols, defoamers, surfactants, etc., but this additive should not adversely affect the drying time.

The ink receiving layer (s) can be formed by any conventional coating technique, such as deposition techniques from a resin solution or dispersion in a solvent or aqueous medium or mixtures thereof, Meyer bar coating, knife coating, reverse roll coating, rotogravure coating And can be applied to the film backing. If two layers are used, the upper layer may be applied thereon by the same or other conventional process.

Drying of the ink-soluble layer (s) is carried out by conventional drying techniques, such as heating in a hot air oven at a temperature suitable for the particular film backing selected. For example, in the case of polyester film backing, a drying temperature of about 120 ° C is suitable.

The film substrate may be formed from any polymer capable of forming a self-supporting sheet. For example, cellulose esters such as cellulose triacetate or cellulose diacetate, polystyrene, polyamide, vinyl chloride polymers and copolymers, polyolefins and polyallomeric polymers and copolymers, polysulfones, polycarbonates, polyesters, have. Suitable films include one or more dicarboxylic acids or their lower alkyl diesters wherein the number of carbon atoms in the alkyl group is up to six such as terephthalic acid, isophthalic acid, phthalic acid, 2,5-naphthalene dicarboxylic acid, Naphthalene dicarboxylic acid, succinic acid, sebacic acid, adipic acid and azelaic acid with at least one glycol such as ethylene glycol, 1,4-butanediol, and the like.

Preferred film substrates or backings are cellulose triacetate or cellulose diacetate, poly (ethylene naphthalate), polyesters, especially poly (ethylene terephthalate), and polystyrene films. Poly (ethylene terephthalate) is most preferred. The thickness of the caliper of the film backing is preferably in the range of 50 탆 to 200 탆. If the thickness of the caliper of the film backing is less than 50 μm, it is difficult to handle with conventional methods used for graphic materials. Film backing with caliper thicknesses greater than 200 microns is stiffer and presents a problem with the supply in some commercially available ink jet printers and pen plotters.

When a polyester film base material is used, the base material can be oriented in two axes in order to impart molecular directionality, and thermosetting can be performed for stereoscopic stability while fusing an image to a support. These films can be produced by any conventional extrusion method.

In order to enhance the adhesion of the ink receiving layer to the film backing, it may be desirable to treat the surface of the at least one undeleted film backing with a single or multiple layers. Useful subbodies include those known to have an expansion effect on film backing polymers. Examples include halogenated phenols dissolved in organic solvents. Alternatively, the surface of the film backing can be modified by treatments such as corona treatment or plasma treatment.

The image-water-soluble coating of the present invention is particularly useful for an ink-receiving sheet that produces an image-formed transparency, for example, when viewed in a transmission mode or a reflective mode in an overhead projector (OHP).

The following examples are cited for the purpose of illustration only and are not intended to limit the scope of the invention, and the scope of the invention is defined by the claims.

Test Methods

Image density

The transmission image density is measured using a Macbeth TD 903 density meter equipped with an A grade gold filter.

Drying time

The environmental conditions for carrying out this test are 70 ° C and 50% relative humidity (RH). The printing pattern consists of a solid-filled column of adjacent colors. The column is 0.64 cm to 15.24 cm wide and 15.24 cm to 22.86 cm long. After printing, the material is placed on a flat surface and then contacted with bond paper. A 2 kg rubber roller with a width of 6.35 cm is rotated twice over the paper. Then, after taking out the paper, the drying time D _T is calculated using the following equation:

[ Equation 1 ]

D _T = T _D + (L _T / L _P ) T _P

In the above equation, T _D is the time from the end of printing until the image is brought into contact with the binding paper. L _T is the image transfer length to paper, L _P is the length of the printed column, and T _P is the printing time.

Examples 1-2 and Comparative Examples 3C-5C

These embodiments were made to have only a single receptive layer. It was coated as follows:

20 g of a 10% aqueous solution of polyvinylpyrrolidone (available as PVP-K-90 from ISP), 10% aqueous solution of polyoxyethylene aryl ether plasticizer (available as Pycal (R) 94 from InterNational Chemical Industries ) And 10 g of a 20% aqueous solution of a polyethylene-acrylic acid copolymer in water / ammonium hydroxide (available as Primacor (R) from Dow Chemical). After mixing, the mixture was coated on a polyethylene terephthalate (PET) film treated with 100 탆 thick polyvinyl chloride (PVDC) to a wet thickness of 200 탆 and dried at 126 캜 for 2.5 minutes.

Example 2 was coated in a similar manner using the same concentration of Pycal < (R) > 94. Various polymer compositions are shown in Table 1.

[ Table 1 ]

These single-layer ink-soluble sheets were tested in the same manner as described above, and the results are shown in Table 2.

[ Table 2 ]

These examples illustrate the effect of the Primacor (R) / PVP mixture upon drying.

Example 6

An example of this two layer was made by making a sublayer similar to the single layer prepared in Example 1 and then overcoating this layer with the top layer prepared as follows:

Ten grams of a 1.25% aqueous solution of K15M was mixed with 10 g of Methocel 占 (Dow product cellulose ether; binder, thickener, film former, etc.), Methocel 占 (Dow product cellulose ether; 10 g of a 1% solution of J5MS, 0.8 g of a 28% aqueous solution of PTSA / PEI in a ratio of 1: 1.8, 0.8 g of a 5% boric acid aqueous solution, Ludox TM (DuPont Products) aqueous colloidal silica dispersant, 0.2 g of a 30% aqueous solution of LLS and 0.5 g of a 10% aqueous solution of LokSiz TM (industrial starch corn starch) 30 were mixed. Drying time was cyan 0.5 min; Magenta 0.5 min; Red 3.5 min; Blue 3.5 min and black 8.0 min.

Examples 7-9

These ink-soluble sheets were two-layer films. The lower layer was prepared using the same formulation as used in Example 2, and the upper layer was as shown in Table 3.

[ Table 3 ]

These sheets were also tested as above, and the results are presented in Table 4. Example 9 showed dry heat, which shows that the upper layer is prone to dry heat in the case of a two-layer coating system made without a modified cellulosic binder.

[ Table 4 ]

Examples 10-11C

These examples relate to two-layer films, in which the bottom layer of Example 2 is used for the bottom layer of Example 10, and the compositions of the bottom layer and both top layers of Example 11C are shown in Table 5. [

[ Table 5 ]

These ink-soluble sheets were tested using Deskjet ^TM 500C. Drying time and dry heat results are shown in Table 6.

[ Table 6 ]

Claims (9)

A liquid-absorbent underlayer having a thickness of 10 to 40 占 퐉 and a thinner ink-permeable upper layer having a thickness of 0.5 to 10 占 퐉, the polyethylene-acrylic acid copolymer containing acrylic acid in an amount of 10% by weight or more and the hydrophilic liquid- An ink-soluble coating suitable for use in an ink-soluble sheet comprising: A single-layer ink water-soluble coating suitable for an ink-soluble sheet comprising a polyethylene-acrylic acid copolymer and a hydrophilic liquid-absorbent polymer containing at least 10% by weight of acrylic acid. The ink-soluble coating according to any one of claims 1 to 3, wherein the polyethylene-acrylic acid copolymer contains at least 20% by weight of acrylic acid. The method according to claim 1, wherein said underlayer is selected from the group consisting of polyacrylamide, polyvinylpyrrolidone, modified polyvinylpyrrolidone, polyethylene-acrylic acid copolymer, polyvinyl alcohol, and modified polyvinyl alcohol. Lt; RTI ID = 0.0 > ink-soluble < / RTI > coating. The ink-soluble coating of claim 1, wherein the top layer comprises high viscosity cellulose selected from the group consisting of methylcellulose, hydroxypropylmethylcellulose, and mixtures thereof. The ink-soluble coating of claim 1, wherein the lower layer comprises a mixture of a polyethylene-acrylic acid copolymer and polyvinylpyrrolidone. The method of claim 1, a) a high viscosity methylcellulose binder, hydroxypropyl methylcellulose, or mixtures thereof, and b) an organic acid salt selected from the group consisting of a salt of polyethyleneimine and a salt of substituted polyethyleneimine. The ink-soluble coating of claim 1, wherein the upper layer comprises a mordant. A film comprising a coating according to claim 1 or 2 and comprising a transparent triacetate selected from the group consisting of cellulose triacetate or cellulose diacetate, poly (ethylene naphthalate), polyester, especially poly (ethylene terephthalate), and polystyrene film An ink-soluble sheet comprising a substrate.