JPH11192777A - Recording sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording sheet having a colorant receptive layer including an excellent water resistance to be easily formed with scarce crack at the time of coating and drying by obtaining an image sheet by an ink jet recording, thermal transfer recording or an electrophotographic recording. SOLUTION: In the recording sheet comprising a colorant receptive layer on a support, the receptive layer is a water soluble resin cured film containing inorganic fine particles and a mordant. The sheet preferably has the colorant receptive layer obtained by coating the support with the fine particles and water soluble resin, giving a solution containing a crosslinker for crosslinking the resin and the mordant simultaneously with the coating or before the coated layer exhibits a falling drying speed and curing it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording sheet for recording an image (including a character image) using a coloring material. In particular, the present invention relates to a recording sheet that is advantageously used for forming an image sheet by inkjet recording, thermal transfer recording, electrophotographic recording, or the like.

[0002]

2. Description of the Related Art In recent years, with the rapid development of the information industry, various information processing systems have been developed, and recording systems and apparatuses suitable for each information system have also been developed and adopted. Among such recording methods, an ink recording method using an ink jet or a plotter, and a thermal transfer recording method using a fusion type color material or a sublimation type color material can easily reduce the weight and size of the apparatus used. It is known that there is no noise and the operability and maintainability are excellent. Further, in such a recording method, formation of a color image is also easy. It should be noted that colorization is progressing even in a conventional electrophotographic recording system, and printers and copying machines capable of high resolution and full color have been developed and commercialized.

Various types of ink jet systems have been developed, and are roughly divided into a method using a dye solution containing a water-soluble dye (aqueous ink), a method using a dye solution containing an oil-soluble dye (oil-based ink), There are three types of methods in which a low-melting solid wax (wax ink) containing a dye is melted by heat. The mainstream is a type using an aqueous ink. In any of these methods, an image is formed by ejecting fine droplets of ink onto the surface of an ink recording sheet and then drying or cooling the ink to solidify the ink.

The thermal transfer system is roughly classified into two types. In the first method, heat is applied in a pattern from the support to an ink sheet having a heat-meltable ink layer formed on a support, whereby the ink layer is melted in a pattern and the molten ink is used for recording. The second method is a method of transferring an image to a sheet to obtain an image (melt heat transfer). The second method uses a heat-sensitive recording material in which an ink layer composed of a resin having a high softening point and a sublimable dye is formed on a support. Similarly, heat is applied from the support side to sublimate the sublimation dye in a pattern,
This is a method of transferring an ink image onto a recording sheet to obtain an image (sublimation heat transfer). In electrophotography, an electrostatic latent image is formed by applying a light image pattern to a charged photoconductive layer,
Then, after developing with toner, a method of transferring a toner image to a recording sheet and fusing and fixing the toner by heat is the mainstream.

On the other hand, there are cases where it is necessary to form an image on a transparent sheet. In this case, a transparent film having a transparent colorant receiving (absorbing) layer on the surface is used as a recording sheet, and a transparent image is transferred onto the transparent recording sheet by using any of the above methods. . By forming a transparent image on such a transparent recording sheet, for example,
An OHP film used in place of a slide, a backlight display film used in place of a printed poster or a display board, and a second original drawing film are produced.

A recording sheet (transparent film) on which an image (a transparent image or a light-transmitting image) is formed by the above-described recording method, requires that the obtained image exhibit excellent hue, saturation, and brightness. Further, it is necessary that the color material forming the image is firmly adhered to the surface of the recording sheet,
Further, in the case of ink jet recording, it is required to absorb liquid ink quickly and to prevent ink bleeding or ink pooling in order to obtain a fine image.

[0007] In order to solve these problems, various proposals have hitherto been made. For example, JP-A-57-1
JP-A-4091 and JP-A-61-19389 propose a recording sheet comprising a transparent support and a transparent layer of colloidal silica and a water-soluble resin provided thereon. However, in this transparent layer, the colloidal silica particles are too large and the amount of the water-soluble resin is too large, so that a sufficiently large porosity cannot be obtained. Therefore, the recording sheet shows a sufficiently large ink absorption rate. There is a problem that it is difficult.

Further, JP-A-2-276670 and JP-A-3-281383 disclose a recording sheet provided with a coloring material receiving layer having pores formed of pseudo-boehmite fine particles. . According to the study of the present inventor, it has been found that although this recording sheet shows high ink absorbency, it has a high refractive index, so that sufficiently high transparency cannot be obtained.

Japanese Patent Application Laid-Open No. Sho 61-53598 discloses a support having thereon a transparent layer comprising synthetic silica, fine particles having a refractive index of 1.44 to 1.55, and a water-soluble resin. A recording sheet having the same is disclosed. Synthetic silica usually has a primary particle size exceeding 10 nm, and the secondary particles have a particle size of several hundred nm. Such secondary particles tend to scatter light, and thus a recording sheet containing such particles does not exhibit sufficiently high light transmittance. Further, since the transparent layer has relatively large pores due to large secondary particles, it is not possible to sufficiently prevent ink bleeding and ink accumulation.

[0010] As a recording sheet for solving the above problems,
JP-A-7-276789 proposes a recording sheet in which a color material receiving layer having a high porosity three-dimensional structure formed of inorganic fine particles and a water-soluble resin is provided on a transparent support. . According to this configuration, the ink absorbency and the suppression of color mixture bleeding are sufficient, and an image with high resolution can be obtained.

[0011]

SUMMARY OF THE INVENTION An object of the present invention is to provide a recording sheet provided with a coloring material receiving layer made of inorganic fine particles and a water-soluble resin exhibiting high transparency and excellent fixing properties of a coloring material. Aim.

The inorganic fine particles used in a high porosity color material receiving layer formed of inorganic fine particles and a water-soluble resin generally have small particles, and the content of the particles in the color material receiving layer is large. When applying a coating solution containing a material for forming such a color material receiving layer, according to the study of the present inventor, cracks may occur while the coating layer is dried. It became clear. It has also been found that this crack is likely to occur particularly when drying is performed at a relatively high temperature in order to shorten the drying time. As a method for preventing this cracking, Japanese Patent Laid-Open No. 9-1 is disclosed.
Japanese Patent Application Publication No. 09545 proposes a method of making the viscosity of a binder of a coating solution relatively high. However, in this method, coating unevenness or the like is apt to occur, which leads to a decrease in workability of coating formation of a color material receiving layer. It is not preferable. Further, this method is not sufficient in the effect of preventing cracks.

In order to prevent the above-mentioned color material receiving layer from cracking, the present inventor has studied repeatedly. The coating material layer is formed by applying a coating solution for forming a color material receiving layer on a support and then drying the coating material. It has been clarified that it occurs on the way, that is, at the time of transition from constant rate drying to reduced rate drying. Based on this finding, the present inventor further studied and, in a constant-rate drying state before the reduced-rate drying state started, a recording sheet prepared so as to increase the film strength of the coating layer as soon as possible. Completed the invention.
This invention is described in Japanese Patent Application No. 9-296285. In this application, an example in which a silane coupling agent is applied on a porous film to impart water resistance is shown, but as a result of repeated studies by the present inventors, a mordant is applied simultaneously with a crosslinking agent. The present inventors have found that water resistance can be improved also by the method described above, and have reached the present invention.

Therefore, according to the present invention, an image sheet can be obtained by ink jet recording, thermal transfer recording, or electrophotographic recording, and cracks are less likely to occur during coating and drying, and excellent water resistance can be easily formed. It is another object of the present invention to provide a recording sheet having a color material receiving layer.

In particular, the present invention can prevent uneven absorption of ink by rapidly absorbing liquid ink, and can form a fine image without causing ink bleeding or ink accumulation. An object of the present invention is to provide a recording sheet having a water-resistant coloring material receiving layer which can be easily formed without generating cracks during coating and drying, and which is particularly suitable for inkjet recording.

[0016]

According to the present invention, there is provided a recording sheet having a color material receiving layer provided on a support, wherein the color material receiving layer is formed of a water-soluble resin containing inorganic fine particles and a mordant. The recording sheet is a cured film. The present invention also provides a colorant receiving layer in which a coating solution containing inorganic fine particles and a water-soluble resin is coated on a support, and at the same time as the coating or before the coated layer exhibits a reduced rate drying rate. The recording sheet is also a layer obtained by applying and curing a solution containing a crosslinking agent capable of crosslinking a water-soluble resin and a mordant. In the present invention, the colorant receiving layer may further comprise a coating liquid containing inorganic fine particles and a water-soluble resin, and a solution containing a cross-linking agent, a barrier liquid comprising a material that does not react with the cross-linking agent (provided that the solution containing the cross-linking agent or The above-mentioned recording sheet, which is a layer obtained by simultaneously applying the composition on a support with a mordant contained in at least one of the barrier liquids) and curing the same, is also included.

Preferred embodiments of the recording sheet of the present invention are as follows. (1) The crosslinking agent is a boron compound (especially, borax). (2) The inorganic fine particles are silica fine particles having an average primary particle diameter of 20 nm or less (preferably 10 nm or less, particularly in the range of 3 to 10 nm). (3) The water-soluble resin is polyvinyl alcohol or gelatin. (4) The weight ratio of the inorganic fine particles to the water-soluble resin is 1.5: 1.
-10 to 10: 1 (inorganic fine particles: water-soluble resin). (5) The color material receiving layer has a porosity of 40 to 80% (particularly 50 to 80%).
80% porosity).

(6) The recording sheet is for ink jet recording. (7) The coating amount of the crosslinking agent-containing solution on the colorant receiving layer is in the range of 0.01 to 10 g / m ^{2 in} terms of the crosslinking agent (particularly,
0.05-5 g / m ² ). (8) The colorant receiving layer has a three-dimensional network structure. (9) The colorant receiving layer has a haze of 30% or less. (10) The above recording sheet for ink jet recording, wherein the layer thickness of the colorant receiving layer is 10 to 50 μm. (11) The above-mentioned recording sheet for electrophotography or thermal recording wherein the layer thickness of the colorant receiving layer is 0.1 to 10 μm. (12) The mordant contained in the colorant receiving layer is a basic polymer.
It is.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The recording sheet of the present invention has a basic structure comprising a support and a colorant receiving layer formed on the support, and can be produced, for example, as follows. .

As a material that can be used as the support, a transparent material such as plastic or an opaque material such as paper may be used. In the invention, in order to utilize the transparency of the colorant receiving layer, the support is preferably a transparent support or a high gloss opaque support. As a material that can be used as the transparent support, a material that is transparent and has a property of withstanding radiant heat when used in an OHP or a backlight display is preferable. Examples of such a material include polyesters such as polyethylene terephthalate; cellulose esters such as nitrocellulose, cellulose acetate, cellulose acetate butyrate; and polysulfone, polyphenylene oxide, polyimide, polycarbonate, polyamide, and the like. Among these, polyesters are preferred, and polyethylene phthalate is particularly preferred. Regarding the thickness of the transparent support,
There is no particular limitation, but those having a size of 50 to 200 μm are preferred because they are easy to handle.

The high gloss opaque support preferably has a surface on the side on which the colorant receiving layer is provided having a glossiness of 40% or more. The glossiness is in accordance with JIS P-8142
This is a value obtained by measuring according to the method described in (Test Method for Specular Gloss at 75 ° of Paper and Paperboard). Examples of high-gloss opaque supports include high-gloss papers such as art paper, coated paper, cast-coated paper, and baryta paper used for silver halide photographic supports; polyesters such as polyethylene terephthalate (PET); High gloss (surface calendering) by adding white pigments etc. to cellulose esters such as nitrocellulose, cellulose acetate and cellulose acetate butyrate, or plastic films such as polysulfone, polyphenylene oxide, polyimide, polycarbonate and polyamide Etc.) or a film in which a polyolefin coating layer containing or not containing a white pigment is provided on the surface of the above-mentioned various papers, the above-mentioned transparent plastic film or a plastic containing a white pigment or the like. It can be. Furthermore, a foamed polyester film containing a white pigment (eg, a calcium-containing foamed PET containing fine particles of polyolefin and forming voids by stretching) can also be mentioned. Polyolefin-coated paper (a paper support having a white pigment-containing polyolefin layer on its surface) or a special-purpose paper provided with a metal-deposited layer or the like, which is generally used as a silver salt photographic support, It can be suitably used. In particular, a paper support provided with a white pigment-containing polyolefin layer, a polyester (preferably PET) film provided with a white pigment-containing polyolefin layer, a white pigment-containing polyester film, or a white pigment-containing foamed polyester film is preferable. There is no particular limitation on the thickness of the opaque support, but a thickness of 50 to 200 μm is preferred because it is easy to handle.

As the support, those subjected to a corona discharge treatment, a flame treatment, or an ultraviolet irradiation treatment may be used.

The colorant-receiving layer of the recording sheet of the present invention may be formed such that when a coating solution containing inorganic fine particles and a water-soluble resin is applied on a support, the coating layer is dried at the same time as the application or at a reduced rate. It is preferable that a water-soluble resin obtained by applying a solution containing a cross-linking agent and a mordant onto the coating layer before the speed is reached and hardening the same is a layer cured by the cross-linking agent.

Further, the colorant receiving layer of the recording sheet of the present invention comprises a coating liquid containing inorganic fine particles and a water-soluble resin, and a solution containing a crosslinking agent, which are made of a barrier liquid made of a material which does not react with the crosslinking agent. , At least one of a solution containing a cross-linking agent or a barrier solution containing a mordant) is applied to a support in a state where the mordant is sandwiched, and cured.

Examples of the water-soluble resin include polyvinyl alcohol (PVA), which is a resin having a hydroxyl group as a hydrophilic structural unit, cellulose resins [methylcellulose (MC), ethylcellulose (EC), hydroxyethylcellulose (HEC), and carboxy. Methylcellulose (CMC), etc.], chitins and starch; polyethylene oxide (P
EO), polypropylene oxide (PPO), polyethylene glycol (PEG) and polyvinyl ether (PVE); and polyacrylamide (PAAM) and polyvinylpyrrolidone (PVP), which are resins having an amide group or an amide bond. Further, polyacrylates having a carboxyl group as a dissociable group, maleic acid resins, alginates, and gelatins can be exemplified.

Examples of the inorganic fine particles include silica fine particles, colloidal silica, calcium silicate, zeolite,
Examples include kaolinite, halloysite, muscovite, talc, calcium carbonate, calcium sulfate, boehmite, pseudo-boehmite and the like. From the viewpoint of not lowering the transparency, those having a refractive index in the range of 1.40 to 1.60 are preferable. Among these, silica fine particles are preferred. The average primary particle diameter of the inorganic fine particles is generally 20 nm or less (preferably 10 nm or less, particularly 3 to 10 nm), and the refractive index is preferably around 1.45.

Since the silica particles are liable to adhere to each other due to hydrogen bonding due to silanol groups on the surface, a structure having a particularly high porosity can be formed when the average primary particle diameter is particularly 10 nm or less as described above. The ink absorption characteristics are improved. Silica particles are roughly classified into wet process particles and dry process particles according to the production method. In the wet method, the mainstream is a method in which active silica is generated by acid decomposition of a silicate, which is appropriately polymerized, coagulated and sedimented to obtain hydrated silica. On the other hand, the dry method is a method based on high-temperature gas phase hydrolysis of silicon halide (flame hydrolysis method), a method in which silica sand and coke are heated and reduced by an arc in an electric furnace and oxidized with air (arc method). The method of obtaining anhydrous silica by the method (2) is mainly used. The hydrated silica and anhydrous silica obtained by these methods differ in the density of silanol groups on the surface, the presence or absence of vacancies, etc., and show different properties, respectively. In the case of silicic anhydride (anhydrous silica), It is preferable because a three-dimensional structure having a high porosity can be easily formed. Although the reason for this is not clear, the density of silanol groups on the surface of hydrated silica is as large as 5 to 8 particles / nm ^2, and the particles are likely to be densely aggregated (aggregate). to three / nm ² and for small, coarse flocculation (flocculate) and porosity is estimated to be due to become high structure.

From the viewpoint of transparency, the type of resin to be combined with the silica fine particles is important. When anhydrous silica is used, the water-soluble resin is PVA, particularly a low saponification degree (preferably a saponification degree of 70 to 90). %) Of PVA is preferable from the viewpoint of light transmittance. PVA has a hydroxyl group in the structural unit, and the hydroxyl group and a silanol group on the surface of the silica particle form a hydrogen bond, thereby easily forming a three-dimensional network structure having a secondary particle of the silica particle as a chain unit. Thereby, it is considered that a color material receiving layer having a structure with a high porosity is formed.
In the ink jet recording, the porous layer thus obtained not only absorbs ink rapidly by a capillary phenomenon and enables fine recording without ink bleeding or ink accumulation, but also a coloring material in thermal recording, and an electronic material. The toner in photographic recording can be firmly adhered. The reason is that the coloring material or the toner penetrates into the pores of the porous layer, and as a result, a shape anchor effect caused by the three-dimensional network structure occurs, thereby firmly fixing the coloring material and the like. Is understood to be. In addition, since the ratio of the inorganic fine particles is increased, heat resistance is high and emboss resistance in electrophotographic recording is also high.

The ratio of the inorganic fine particles (preferably silica fine particles) to the water-soluble resin (PB ratio: the weight of the inorganic fine particles with respect to the weight of the water-soluble resin of 1) has a great influence on the film structure of the colorant receiving layer. As the PB ratio increases, the porosity, pore volume, and surface area (per unit weight) increase. If the PB ratio exceeds 10, there is no effect on film strength and cracking during drying. On the other hand, if the PB ratio is less than 1.5, the voids are easily closed by the resin, the porosity decreases, and the ink absorption performance decreases. Therefore, the PB ratio is preferably in the range of 1.5 to 10. In particular, when an image on a recording sheet is often directly touched by hand, as in the case of an OHP film, the colorant receiving layer needs to have sufficient film strength. In this case, the PB ratio is particularly preferably 5 or less, and the PB ratio is preferably 2 or more, and particularly preferably in the range of 2 to 5 in order to obtain high-speed ink absorption by an ink jet printer. It is.

For example, when a coating liquid in which anhydrous silica having an average primary particle diameter of 10 nm or less and a water-soluble resin are completely dispersed in an aqueous solution with a PB ratio of 2 to 5 is applied and dried, the secondary particles of silica particles are chained. A three-dimensional network structure as a unit is formed,
The average pore size is 30 nm or less, the porosity is 50% or more, the pore specific volume is 0.5 mL / g or more, and the specific surface area is 100 m ^2.
/ G or more can be easily formed.

The coloring material receiving layer of the recording sheet of the present invention is a layer (porous layer) containing inorganic fine particles and a water-soluble resin as main components.
Is a layer in which a crosslinking agent and a mordant are provided, and the water-soluble resin is cured by the crosslinking agent. The application of the crosslinking agent is preferably performed at the same time as the application of the coating liquid for forming a porous layer, or before the coating liquid layer for forming a porous layer exhibits a reduced drying rate. By this operation, it is possible to effectively prevent cracks generated during drying of the coating layer of the coating liquid for forming a porous layer. That is, at the same time that the coating liquid for forming a porous layer is applied, or before the coating layer exhibits a reduced drying rate, the crosslinking agent-containing solution penetrates into the coating layer, and the water-soluble property in the coating layer is increased. By reacting quickly with the resin and polymerizing (curing) the water-soluble resin, the film strength of the coating layer is immediately and greatly improved. As a result, cracks generated when the coating layer of the coating liquid for forming a porous layer is dried can be effectively prevented.

Examples of the crosslinking agent used for forming the colorant receiving layer of the recording sheet of the present invention include borax, boric acid, and borate (eg, orthoborate, InBO ₃ , ScBO ₃ , YBO).
₃ , LaBO ₃ , Mg ₃ (BO ₃ ) ₂ , Co ₃ (BO ₃ ) ₂ , diborate (eg, Mg ₂ B ₂ O ₅ , Co ₂ B ₂ O ₅ ), metaborate (eg, LiBO ₂₎ , Ca (BO ₂ ) ₂ , NaBO ₂ ,
KBO ₂ ), tetraborate (eg, Na ₂ B ₄ O ₇ .10H ₂₎
O), five borate _{(e.g., KB 5 O 8 · 4H 2} O, Ca 2 B 6
_{O 11 · 7H 2 O, CsB} 5 O 5), glyoxal, melamine-formaldehyde (for example, methylol melamine, alkylated methylol melamine), methylol urea, resol resin, and polyisocyanate. Of these, borax, boric acid or borate is preferred. It is preferable to use borax, boric acid, and borate in combination with polyvinyl alcohol as a water-soluble resin because a crosslinking reaction occurs promptly.

When gelatin is used as the water-soluble resin, the following compounds known as gelatin hardeners can be used as crosslinking agents. Aldehyde compounds such as formaldehyde, glyoxal and glutaraldehyde; ketone compounds such as diacetyl and cyclopentanedione; bis (2-chloroethylurea) -2-
Active halogen compounds such as hydroxy-4,6-dichloro-1,3,5-triazine, 2,4-dichloro-6-S-triazine sodium salt; divinylsulfonic acid;
1,3-vinylsulfonyl-2-propanol, N,
N'-ethylenebis (vinylsulfonylacetamide),
Active vinyl compounds such as 1,3,5-triacryloyl-hexahydro-S-triazine; N-methylol compounds such as dimethylol urea and methylol dimethylhydantoin; isocyanate compounds such as 1,6-hexamethylene diisocyanate; Description 3017280
And carboxyimide compounds described in U.S. Pat. No. 3,100,704; epoxy compounds such as glycerol triglycidyl ether; and 1,6-hexamethylene-N. , N'-bisethylene urea and other ethyleneimino compounds; halogenated carboxaldehyde compounds such as mucochloric acid and mucophenoxycyclolic acid;
Dioxane compounds such as 2,3-dihydroxydioxane; chrome alum, potassium alum, zirconium sulfate, chromium acetate and the like. These hardeners (crosslinking agents) can be used alone or in combination of two or more.

The solution of the crosslinking agent is prepared by dissolving the crosslinking agent in water and / or an organic solvent. The concentration of the cross-linking agent in the cross-linking agent solution is preferably 0.05 to 10% by weight, particularly 0.1 to 10% by weight.
7% by weight is preferred. Water is generally used as a solvent for the crosslinking agent. Any organic solvent can be used as long as it can dissolve the crosslinking agent. Examples thereof include alcohols such as methanol, ethanol and isopropyl alcohol; ketones such as acetone and methyl ethyl ketone; esters such as methyl acetate and ethyl acetate; Aromatic solvents such as toluene; ethers such as tetrahydrofuran; and halogenated carbon-based solvents such as dichloromethane.

In the present invention, the water resistance is improved by applying a mordant together with a crosslinking agent. When a mordant is added to the coating liquid for forming a porous layer, aggregation may occur due to the anionic charge on the surface of the inorganic fine particles such as silica and the cationic nature of the mordant, but each is prepared as an independent solution and applied. Utilizing the method, there is no fear of aggregation of inorganic fine particles such as silica, and the selection range of the mordant is widened.

As the mordant, amide groups, imide groups, 1
At least one selected from a secondary amino group, a secondary amino group, a tertiary amino group, a primary ammonium base, a secondary ammonium base, a tertiary ammonium base, and a quaternary ammonium base
Compounds containing various kinds of cationic groups, for example, polyvinylbenzyltrimethylammonium chloride, polydiallyldimethylammonium chloride,
Polymethacryloyloxyethyl-β-hydroxyethyldimethylammonium chloride, polydimethylaminoethyl methacrylate hydrochloride, polyethyleneimine, polyallylamine, polyallylamine hydrochloride, polyamide-polyamine resin, cationized starch, dicyandiamide formalin condensate, A dimethyl-2-hydroxypropyl ammonium salt polymer and the like can be mentioned. These compounds preferably have a molecular weight of about 1,000 to 20,000. If the molecular weight is less than 1,000, the water resistance tends to be insufficient, and if it is more than 200,000, the viscosity becomes high and the handling suitability becomes poor.

In manufacturing the recording sheet of the present invention,
When a coating liquid (coating liquid for forming a porous layer) containing inorganic fine particles and a water-soluble resin as main components is coated on a support, a cross-linking agent is applied so that the coating layer does not crack, and is promptly added. It is desirable to use a method of improving the film strength of the coating layer and simultaneously applying a mordant to improve the water resistance.
In practice, a solution containing a crosslinking agent and a mordant is applied simultaneously with the application of a coating solution containing inorganic fine particles and a water-soluble resin as main components (in this case, a solution containing inorganic fine particles and a water-soluble resin as main components). It is desirable that a barrier liquid made of a material that does not react with the crosslinking agent is interposed between the coating solution, the solution containing the crosslinking agent and the mordant, and in this case, the mordant may be contained in the barrier liquid. Alternatively, it is desirable to use a method of applying a solution containing a cross-linking agent and a mordant immediately after applying a coating solution containing inorganic fine particles and a water-soluble resin as main components.

Next, after applying a coating liquid (coating liquid for forming a porous layer) containing inorganic fine particles and a water-soluble resin as main components,
A method for quickly applying a solution containing a cross-linking agent and a mordant before the coating layer exhibits a reduced drying rate will be described.

The coating liquid for forming a porous layer is prepared by adding silica fine particles having an average primary particle diameter of 10 nm or less to water (for example, 10 to 20% by weight), and using a high-speed rotating wet colloid mill (for example, CLEARMIX (EM)・ Technique Co., Ltd.))
Using, for example, 10,000 rpm (preferably 500 rpm).
After dispersing for 20 minutes (preferably 10 to 30 minutes) under the condition of high-speed rotation of 0 to 20,000 rpm, an aqueous polyvinyl alcohol solution (for example, so that the PVA weighs about 1/3 of silica) is added. It can be obtained by performing dispersion under the same conditions as above. The coating solution thus obtained is a uniform sol, and a porous layer having a three-dimensional network structure can be obtained by forming this on a support by the following coating method.

The application of the coating liquid for forming a porous layer is performed, for example, by
It can be carried out by applying a coating solution obtained by further adding an antistatic agent or the like, if desired, onto a support (film). The coating can be performed by a known coating method such as an extrusion die coater, an air doctor coater, a bread coater, a rod coater, a knife coater, a squeeze coater, a reverse roll coater, and a bar coater.

After the application of the coating liquid for forming a porous layer, before the coating layer exhibits a reduced drying rate,
The solution containing the cross-linking agent and the mordant of the present invention is applied in the same manner as the coating liquid for forming a porous layer, and dried to obtain the cured color material receiving layer of the present invention. The solution containing the crosslinking agent and the mordant may be applied by a method such as spraying.

The time before the coated layer exhibits the decreasing rate drying rate is usually several minutes immediately after the coating, during which the content of the solvent in the coated layer decreases in proportion to the time. It shows the constant rate drying rate, which is a phenomenon that occurs. For the time indicating such a constant rate drying rate, see the Chemical Engineering Handbook (70
7-712 pages, published by Maruzen Co., Ltd., October 2, 1980
5).

The coloring material receiving layer of the recording sheet of the present invention contains a crosslinking agent and a mordant after the application of the coating liquid for forming a porous layer and the coating layer shows a constant drying rate. It is preferably manufactured by applying a solution by a method such as coating or spraying. Drying after the application of the coating liquid for forming a porous layer is generally performed at 50 to 180 ° C. for 0.5 to 10 minutes (particularly 0.5 to 5 minutes). This drying time naturally depends on the amount of application, but the above range is appropriate.

In the coating layer of the coating solution for forming a porous layer, the support having the coating layer is immersed in a solution containing a cross-linking agent and a mordant within a period in which the coating layer exhibits a constant drying rate. The crosslinking agent and the mordant can also be introduced into the coating layer of the coating liquid for forming a porous material by spraying a solution containing a crosslinking agent and a mordant onto the coating layer by spraying. When applying a coating solution containing a crosslinking agent and a mordant, in addition to the above method, a curtain flow coater,
Known application methods such as an extrusion die coater, an air doctor coater, a bread coater, a rod coater, a knife coater, a squeeze coater, a reverse roll coater, and a bar coater can be used, but an extrusion die coater, a curtain flow coater, a bar coater, etc. It is preferable to use a method in which the coater does not directly contact the coating layer.

The coating amount of the coating solution containing the cross-linking agent and the mordant on the colorant receiving layer is 0.01 to 10 g / in terms of the cross-linking agent.
The range of m ² is general, and the range of 0.05 to 5 g / m ² is preferable. After the application of the coating solution containing the crosslinking agent and the mordant, the coating layer is generally heated at 40 to 180 ° C. for 0.5 to 30 minutes to perform drying and curing. 40-150
It is preferable to heat at 1C for 1 to 20 minutes. For example,
When borax or boric acid is used as a cross-linking agent, 60 to 1
Heating at 00 ° C. is preferably performed for 5 to 20 minutes.

Next, another method of forming the colorant receiving layer of the recording sheet of the present invention is to apply a coating liquid (coating liquid for forming a porous layer) containing inorganic fine particles and a water-soluble resin as main components. A method for simultaneously applying a solution containing a crosslinking agent and a mordant will be described. In this method, a coating solution for forming a porous layer and a solution containing a cross-linking agent and a mordant are simultaneously coated on a support in such a manner that the coating solution for forming a porous layer comes into contact with the support and cured. Can be obtained. The simultaneous application of the coating solution for forming the porous layer and the solution containing the crosslinking agent and the mordant can be performed by, for example, an application method using an extrusion die coater or a curtain flow coater. Drying after simultaneous coating (multilayer coating) is generally performed by heating the coating layer at 40 to 150 ° C. for 0.5 to 10 minutes, and the coating layer is cured. The cured layer,
Further, it is preferable to heat at 40 to 100 ° C. for 0.5 to 5 minutes. For example, when using borax or boric acid as a crosslinking agent, it is preferable to heat at 60 to 100 ° C. for 5 to 20 minutes.

When the above-mentioned multi-layer coating is carried out, for example, by an extrusion die coater, the two types of coating liquid form a multi-layer near the discharge port of the extrusion die coater, that is, before transferring onto the support. Then, when the two coating layers (layers) are transferred to the support, a cross-linking reaction easily occurs at the interface between the two layers, so that viscosity increases due to mixing of the discharge coating liquid near the discharge port of the extrusion die coater. In some cases, the application operation becomes troublesome. Therefore, when the above simultaneous coating is performed, the barrier layer liquid (intermediate layer liquid) made of a material that does not react with the crosslinking agent is applied together with the application of the coating liquid for forming the porous layer and the solution containing the crosslinking agent and the mordant. It is preferable that three layers be simultaneously coated so as to be interposed between both coating solutions. What is necessary is just to select the barrier layer liquid which can form a liquid film without reacting with a crosslinking agent. For example, an aqueous solution or water containing a trace amount of a water-soluble resin (used as a thickener) that does not react with a crosslinking agent can be used. Examples of polymers used in consideration of coatability include hydroxypropyl methylcellulose, methylcellulose, hydroxyethylmethylcellulose, polyvinylpyrrolidone,
Gelatin and the like can be mentioned. As described above, a mordant may be contained in the barrier layer liquid.

After coating and drying, the obtained colorant receiving layer is improved in surface smoothness, transparency and coating strength by passing it between roll nips under heat and pressure using, for example, a super calender, a gloss calender or the like. It is possible. However, since such a process lowers the porosity (that is, the ink absorbency decreases), it is necessary to perform the treatment under a condition in which the porosity does not decrease much.

The thickness of the colorant receiving layer obtained as described above must have an absorption capacity to absorb all the droplets in the case of ink jet recording. Must be determined in the context of For example, when the ink amount is 8 nL / mm ² and the porosity is 60%, a film having a thickness of about 15 μm or more is required. Considering this point, in the case of ink jet recording, the color material receiving layer is 1
It is preferable to have a film thickness in the range of 0 to 50 μm. In the case of thermal transfer or electrophotography, a thin film is sufficient because the color material or the toner is adsorbed on the surface, and the color material receiving layer preferably has a thickness of 0.1 to 10 μm.

The inorganic fine particles and the water-soluble resin which mainly constitute the colorant receiving layer may each be a single material or a mixture of a plurality of materials. The colorant receiving layer is mainly composed of the above-mentioned inorganic fine particles and a water-soluble resin, but may further contain various inorganic salts and an acid or alkali as a pH adjuster to enhance the dispersibility of the particles. In addition, various surfactants may be used for the purpose of improving coating suitability and surface quality.
Contains surfactants with ionic conductivity and metal oxide fine particles with electronic conductivity to suppress triboelectric charging and exfoliation charging of the surface, or to adjust surface electrical resistance in electrophotography. Is also good. Further, various matting agents may be included for the purpose of reducing the friction characteristics of the surface. Further, various antioxidants, ultraviolet absorbers, and singlet oxygen quencher may be contained for the purpose of suppressing the deterioration of the coloring material.

Further, an undercoat layer may be provided on the support for the purpose of increasing the adhesiveness between the colorant receiving layer and the support or adjusting the electric resistance. The color material receiving layer may be provided on only one surface of the support, or may be provided on both surfaces of the support in order to suppress deformation such as curling of the recording sheet. When the colorant receiving layer is provided only on one side of the support in the case of using OHP or the like, an antireflection film may be provided on the opposite side or both sides to enhance light transmittance.

[0052]

【Example】

Example 1 A sheet provided with a color material receiving layer for ink jet recording was manufactured by the following method.

[0054]

(1) The composition of the coating solution for forming the porous layer (colorant receiving layer before cross-linking) (the values in parts by weight indicating the blending amounts of all the following coating solutions all represent solids or non-volatiles). ) Anhydrous silica fine particles (average primary particle diameter: 7 nm, 10 parts by weight, surface silanol groups: 2 to 3 particles / nm ² , refractive index: 1.45, trade name: Aerosil 300 (manufactured by Nippon Aerosil Co., Ltd.)) Alcohol (degree of saponification: 81.8%, 3.3 parts by weight Polymerization degree: 4000, trade name: PVA440 (manufactured by Kuraray Co., Ltd.)) 136.0 parts by weight of ion-exchanged water

The silica fine particles were added to ion-exchanged water (73.3 parts by weight), and the mixture was mixed with a high-speed rotating wet colloid mill (CLEARMIX (M Technic Co., Ltd.)
)) And dispersed at 10,000 rpm for 20 minutes, and then an aqueous polyvinyl alcohol solution (dissolved in the remaining 62.7 parts by weight of ion-exchanged water) was added.
Further, dispersion was performed under the same conditions as above to obtain a coating solution for forming a porous layer.

The above coating solution was applied to the surface of a photographic printing paper laminate paper having a thickness of 200 μm at an application amount of 200 cc / m ² using an extrusion die coater, and was then heated to 80 ° C. (wind speed 3 m / sec) by a hot air drier. For 3 minutes. The coating layer exhibited a constant rate of drying during this period. Immediately after drying for 3 minutes, the borax-containing solution of the following (2)
This coating layer was dipped for 1 second and dried at 80 ° C. for 10 minutes. As a result, a color material receiving layer having a dry film thickness of 27 μm was formed.

[0057]

(2) Borax-containing solution Borax 1 part by weight Surfactant 0.2 part by weight (trade name: F-144D, manufactured by Dainippon Ink and Chemicals, Inc.) 1.4% by weight of diallyldimethylammonium chloride / dioxide Parts sulfur copolymer ion-exchanged water 97.4 parts by weight

Example 2 An ink jet recording sheet was prepared in the same manner as in Example 1, except that polyallylamine was used in place of the diallyldimethylammonium chloride / sulfur dioxide copolymer in the borax-containing solution. .

Example 3 Ink jet was performed in the same manner as in Example 1 except that the borax-containing solution was replaced with a dimethyl-2-hydroxypropylammonium chloride polymer instead of the diallyldimethylammonium chloride / sulfur dioxide copolymer. A recording sheet was prepared.

Example 4 An ink jet recording sheet was produced by the following method.

[0061]

[Table 3] Coating solution for forming an intermediate layer 5.5 parts by weight of hydroxypropyl methyl cellulose (Metroze 90SH; viscosity grade 100000 (manufactured by Shin-Etsu Chemical Co., Ltd.)) Surfactant (trade name: F) -144D 2.0 parts by weight (manufactured by Dainippon Ink and Chemicals, Inc.) Deionized water 992.5 parts by weight

In Example 1, three coatings of a coating solution for forming a porous layer and a solution of a crosslinking agent were simultaneously applied using the coating solution for forming an intermediate layer as an intermediate layer. Using an extrusion die coater having a discharge opening of 3 slits, from the side in contact with the support, 200 cc / m ^{2 of} a coating solution for forming a porous layer, 30 cc / m ^{2 of} a coating solution for forming an intermediate layer, and 15 cc / ml of a crosslinking agent solution. Three layers were simultaneously coated with an application amount of m ² and dried at 80 ° C. for 10 minutes.
Thus, a color material receiving layer having a thickness of 27 μm was formed.

Comparative Example An ink jet recording sheet was prepared in the same manner as in Example 1, except that the borax-containing solution did not contain diallyldimethylammonium chloride / sulfur dioxide polymer.

[Evaluation of Inkjet Recording Sheet] The inkjet recording sheet obtained above was evaluated for its suitability for inkjet recording by the following measuring method. (1) Haze haze meter (HGM-2DP; Suga Test Instruments Co., Ltd.)
Was used to measure the parallel light transmittance, and the haze was measured. In order to facilitate the measurement, haze was formed by forming a colorant receiving layer on a 100 μm-thick polyethylene terephthalate film instead of the laminated paper for photographic printing paper used as a support in each of Examples and Comparative Examples. The measurement was performed using the recording sheet obtained as described above.

(2) Porosity Mercury porosimeter (trade name: Poisizer 9320-P)
C2, manufactured by Shimadzu Corporation) to obtain a porosity distribution and calculate the average value. (3) Gloss The gloss of each recording sheet was measured in accordance with the method described in JIS-P-8142 (test method for 75-degree specular gloss of paper and paperboard).

(4) Ink absorption speed Y is applied to the recording sheet by an ink jet printer (trade name: PM-700C, manufactured by Seiko Epson Corporation).
(Yellow), M (magenta), C (cyan), K (black), B
Solid printing of (blue), G (green) and R (red) was performed, and immediately thereafter (approximately 10 seconds later), the paper was contact-pressed, and the presence or absence of transfer of the ink to the paper was determined as follows. AA: Part of the ink was not transferred to the paper. CC: Part of the ink was transferred to paper.

(5) Occurrence of Cracks Each recording sheet was visually observed and evaluated as follows according to the presence or absence of cracks generated on the surface and the size thereof. AA: No cracks observed BB: 1-2 mm length cracks observed CC: 3 mm or longer cracks observed

(6) Water resistance The same printing pattern was formed on a recording sheet using the same printer as that used for the measurement of the ink absorption rate.
Immerse in water for one minute, visually observe the flow of ink,
The evaluation was as follows. AA: Dye did not flow at all. BB: Dye flows overall and color density is low. CC: Dye flows almost completely.

The results of the above evaluation are shown in Table 1 below.

[0070]

[Table 4] Table 1 ─────────────────────────────────── Haze Porosity Gloss Ink Crack Water resistance (%) (%) (%) Absorption rate ─────────────────────────────────── Example 1 12.1 62 52 AA AA AA Example 2 11.9 60 53 AA AA AA Example 3 11.8 61 50 AA AA AA Example 4 11.2 61 51 AA AA AA ──────────────── ─────────────────── Comparative example 12.0 61 52 AA AA BB ─────────────────────── ────────────

[0071]

The recording sheet provided with the colorant receiving layer of the present invention not only can rapidly absorb liquid ink in ink jet recording and can obtain a fine image free of ink bleeding and ink accumulation. A high-quality image excellent in water resistance can be easily formed without causing a crack in the coloring material receiving layer which is a porous layer. Also,
Since the recording material of the present invention is excellent in the absorbability and the prevention of bleeding of the color material receiving layer, the adhesiveness of the color material or the toner is improved even in various recording systems such as thermal transfer recording and electrophotographic recording. Therefore, it can be said that the recording sheet of the present invention is a recording sheet suitable for various recording methods and excellent in productivity.

Claims (10)

[Claims] 1. A recording sheet having a color material receiving layer provided on a support, wherein the color material receiving layer is a cured film of a water-soluble resin containing inorganic fine particles and a mordant. Recording sheet to be recorded. 2. The colorant receiving layer is obtained by applying a coating solution containing inorganic fine particles and a water-soluble resin onto a support, and simultaneously with or simultaneously with the coating, the coated layer exhibits a reduced rate drying rate. The recording sheet according to claim 1, wherein the recording sheet is a layer obtained by applying a solution containing a crosslinking agent capable of crosslinking the water-soluble resin and a mordant before curing the solution. 3. A coating solution containing inorganic fine particles and a water-soluble resin, and a solution containing a cross-linking agent, wherein the color material-receiving layer is made of a barrier liquid made of a material that does not react with the cross-linking agent. The mordant in at least one of the solution or the barrier solution), and simultaneously coat the support on the support,
The recording sheet according to claim 1, which is a layer obtained by curing. 4. The recording sheet according to claim 1, wherein the crosslinking agent is a boron compound. 5. An inorganic fine particle having an average primary particle diameter of 20 n.
The recording sheet according to any one of claims 1 to 4, wherein the recording sheet is silica fine particles having a particle size of m or less. 6. The recording sheet according to claim 1, wherein the water-soluble resin is polyvinyl alcohol. 7. The recording sheet according to claim 1, wherein a weight ratio of the inorganic fine particles to the water-soluble resin is in a range of 1.5: 1 to 10: 1. 8. The recording sheet according to claim 1, wherein the colorant receiving layer has a porosity of 40 to 80%. 9. The mordant according to claim 1, wherein the mordant is a basic polymer.
9. The recording sheet according to any one of Items 8 to 8. 10. The method according to claim 1, which is for ink jet recording.
10. The recording sheet according to any one of items 9 to 9.