JP2002307807A - Ink jet recording sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording sheet, capable of stably obtaining an image having high adhesive properties of a support to a color material acceptive layer, excellent handleability and workability and without bringing about bleeding with time even when the image is preserved in a high temperature and high humidity environment for a long time after printing. SOLUTION: The ink jet recording sheet comprises the color material acceptive layer containing inorganic pigment fine particles, a water soluble resin and a mordant on the surface of the support. In this sheet, the surface of the support in which the acceptive layer is covered, is executed with an atmospheric pressure plasma treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording medium suitable for ink-jet recording using a liquid ink such as an aqueous ink or an oil-based ink, or a solid ink which is solid at ordinary temperature, melted and liquefied, and then used for printing. For more information on materials,
Excellent ink receiving performance, less bleeding over time,
The present invention relates to an inkjet recording sheet having excellent handleability and processability.

[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. Along with this,
Recording methods and apparatuses suitable for each information system have been developed and put into practical use. Among such recording methods, the ink jet recording method is capable of recording on various recording materials, is relatively inexpensive, is compact in hardware, and has high quietness. It has been widely used in youth. Also, with the recent increase in the resolution of inkjet printers, it has become possible to obtain so-called photo-like high-quality recorded materials. With the development of such hardware (devices), recording sheets for inkjet recording have been developed. Have also been developed.

In general, the characteristics required for the recording sheet are (1) quick drying (high ink absorption speed), and (2) proper and uniform diameter of the ink dots (color blur). (3) good granularity, (4) high dot roundness, (5) high color density, (6) high saturation (no dullness) ), (7) that the print portion has good light resistance and water resistance,
(8) No bleeding occurs in the image even after long-term storage,
(9) The whiteness of the recording sheet is high, (10) the storage stability of the recording sheet is good, (11) the deformation and dimensional stability are good (curl is sufficiently small), (1)
2) Good hard running property and (13) excellent handling property and workability. further,
In the application of photo glossy paper used to obtain a so-called photo-like high-quality recorded matter, in addition to the above, glossiness, surface smoothness, photographic paper-like texture similar to silver halide photography, etc. are also required. .

Examples of recording sheets used for ink jet recording include, for example, JP-A-55-51583, JP-A-55-144172, and JP-A-55-15039.
No. 5, No. 56-148582, No. 56-14
Nos. 8583, 56-148584, 56
JP-A-148585, JP-A-57-14091, JP-A-57-38185, JP-A-57-129778, JP-A-57-129979, and JP-A-60-21908
No. 4, JP-A-60-245588, and the like, in which a pigment such as silica and a water-soluble binder are coated on a support such as paper or a plastic film, are known. However, all of these proposed recording sheets have extremely low gloss, and are insufficient for photo glossy paper.

Further, Japanese Patent Application Laid-Open Nos. 2-276670, 3-215082, 3-281383,
JP-A-6-199035 and the like propose a recording sheet using pseudo-boehmite sol and a water-soluble binder. These recording sheets satisfy the required properties to some extent in terms of gloss, but have problems such as high production cost of pseudo-boehmite particles and difficulty in preparing a coating solution.

Further, Japanese Patent Application Laid-Open No. 4-223190 discloses that a base paper coated with borax or boric acid of 0.1 g / m ² or more is coated with 5 to ²⁰ g / m ² of synthetic silica and polyvinyl alcohol ( An inkjet recording sheet provided with a recording layer made of PVA) has been proposed. The above technique is simply intended to improve the coating strength of a recording layer having a low binder content, and is inferior in gloss, so that it is insufficient for photo glossy paper.

Further, a recording material using various water-soluble polymers for obtaining glossiness has been proposed. For example, JP-A-58-89391, JP-A-58-134784, JP-A-58-134786, and JP-A-60-44386.
JP-A-60-132785, JP-A-60-145
Nos. 879 and 60-168651 and 60-
JP-A-171143 and the like, in which polyvinyl alcohol, polyvinylpyrrolidone, gelatin or the like is coated on a support such as paper or a plastic film, are known. These recording sheets are also excellent in glossiness, but are inferior in ink quick-drying properties, so that they are insufficient for use as photo glossy paper.

On the other hand, JP-A-7-276789, JP-A-8-174992, JP-A-11-115308, and JP-A-11-192777 satisfy the above-mentioned required characteristics and manufacturing cost of the ink jet recording sheet. Ink jet recording sheets have been proposed. JP-A-7-276789 proposes a recording sheet in which a coloring material receiving layer formed of inorganic pigment fine particles and a water-soluble resin and having a three-dimensional structure having a high porosity is provided on a support. Have been. According to this configuration,
It is described that the above-described ink absorbency is improved, color mixing during printing is sufficiently suppressed, and an image with high resolution can be obtained. This color material receiving layer can be generally formed by containing a large amount of particles having a small particle diameter. However, since the amount of binder for forming the layer needs to be reduced so as to form voids, the coating layer is rapidly dried. Cracks occur and the transparency and appearance of the colorant receiving layer are impaired.

As a method for preventing the ink receiving layer from cracking, Japanese Patent Application Laid-Open No. 9-109545 proposes a method in which the viscosity of a binder in a coating liquid is relatively high. There is a possibility that coating or uneven coating may occur, and the level is not yet practically effective. Also, JP-A-7-76161, 10-
Japanese Patent No. 119423 discloses a method for preventing cracking using a coating solution composed of inorganic particles, polyvinyl alcohol (PVA), boric acid or borate. However, this method also increases the viscosity of the coating solution. There is a large decrease in workability, and there is also a problem in the stability over time of the liquid, and it has not yet reached a practically effective level.

In JP-A-10-119423 and JP-A-10-217601, a coloring material receiving layer containing fine inorganic pigment particles and a water-soluble resin and having a high porosity is provided on a support. Inkjet recording sheets have been proposed. Each of the above-mentioned ink jet recording sheets has excellent ink absorbability due to its constitution, has high ink receiving performance capable of forming a high-resolution image, and exhibits high gloss. However, from the viewpoint of glossiness and texture, since a support coated with a resin such as polyethylene on both surfaces thereof is used as the support, the high boiling point solvent contained in the colorant receiving layer does not evaporate, and The solvent is not absorbed by the support. Therefore, the high boiling point solvent remains in the color material receiving layer as it is, and after printing, if stored for a long time in a high temperature and high humidity environment, the solvent diffuses with the dye in the color material receiving layer, and the There is a problem that image bleeding (hereinafter, sometimes referred to as “time bleeding”) occurs.

On the other hand, an ink-jet recording sheet having a color material receiving layer on a support can be held in a state where the support and the color material receiving layer provided on the support are sufficiently adhered to each other. Otherwise, a peeling phenomenon occurs during pre-recording or post-recording storage, and it is not possible to maintain a certain product quality. However, in recent inkjet recording sheets, in order to meet the above-mentioned requirements of the sheet properties, an increase in the amount of an additive material such as an inorganic material component and a surfactant, and an improvement in the porosity of the color material receiving layer (60% or more) ), And various technologies have been added to enable high-quality photo-like recording.
The adhesion of the inorganic colorant receiving layer with many voids to the support tends to be significantly reduced. Further, in the process of manufacturing the ink jet recording sheet, it is finally cut into a desired form by a processing machine, but since this cutting is generally performed using a cutter and receives a large impact,
There is also a problem that the color material image receiving layer easily falls off the support.
Dropout of the colorant image receiving layer significantly impairs product quality as an ink jet recording sheet. Furthermore, when the ink jet recording sheet is folded or overlapped and handled, the color material receiving layer or the like may peel off from the support and fall off. For this reason, in order to maintain the product quality of the ink jet recording sheet and improve the handleability thereof, it is important to increase the adhesion between the support and the colorant receiving layer.

In recent years, the support has been subjected to a surface treatment such as a corona discharge treatment, a vacuum glow discharge treatment or a flame treatment to enhance the adhesion between the colorant receiving layer and the support. However, in the corona discharge treatment, sparks may occur and pinholes may be formed in the support, and when the support is a heat-shrinkable film or the like, the film is likely to contract due to heat generation,
Further, there is a disadvantage that the persistence of the surface modification effect of the film is poor. Further, the vacuum glow discharge treatment has drawbacks in terms of productivity and cost. In the case of flame treatment, damage to a support is large, and the treatment surface is likely to be uneven due to fluctuation of the flame. Furthermore, there is a drawback that adjustment is difficult and involves risks.

As described above, while the colorant receiving layer is strong without cracks or the like, it has good ink absorbency and can form a high-resolution and high-density image, and the formed image is high. While securing ink receiving performance such as light resistance and water resistance, it also has excellent surface smoothness and glossiness of the recording surface, and after printing, even if stored for a long time in a high temperature and high humidity environment, bleeding over time will not occur. At present, an ink jet recording sheet that stably holds an image without causing waking and has excellent handleability and processability has not yet been provided.

[0014]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and achieve the following objects. That is, the present invention has a high adhesiveness between the support and the colorant receiving layer, is excellent in handleability and workability, and, after printing, even when stored for a long time in a high-temperature and high-humidity environment, causes bleeding with time. An object of the present invention is to provide an ink jet recording sheet that can stably hold an image without any problem. Also,
The present invention is free of cracks and the like, is strong, and has a high surface gloss, with good ink absorption,
An object of the present invention is to provide an ink jet recording sheet which can form a high-resolution and high-density image, has good color-forming properties, and is excellent in light resistance and water resistance of an image portion.

[0015]

The present inventors have made intensive studies to solve these problems, and as a result, have found that these problems can be solved by using the following ink jet recording sheet. The present application has been reached.

<1> An ink jet recording sheet having a color material receiving layer containing fine inorganic pigment particles, a water-soluble resin and a mordant on the surface of a support, wherein the color material receiving layer of the support is provided. An ink jet recording sheet having a surface subjected to an atmospheric pressure plasma treatment.

<2> The color material receiving layer is formed by applying a first coating solution containing the inorganic pigment fine particles and the water-soluble resin to the surface of the support, and simultaneously with or simultaneously with the coating. During the drying of the formed coating layer and before the coating layer shows a reduced drying rate, applying a second coating liquid containing a crosslinking agent capable of crosslinking the water-soluble resin and the mordant, <1> The ink jet recording sheet obtained by curing.

<3> The inkjet recording sheet according to <2>, wherein the crosslinking agent is a boron compound.

<4> The inkjet recording sheet according to any one of <1> to <3>, wherein the inorganic pigment fine particles are silica fine particles having an average primary particle diameter of 20 nm or less.

<5> The inkjet recording sheet according to any one of <1> to <4>, wherein the water-soluble resin is polyvinyl alcohol.

<6> The mass ratio (i: p) of the inorganic pigment fine particles (i) to the water-soluble resin (p) is 1.5: 1 to 1: 1.
<1> to <5, which are within the range of 10: 1.
&Lt; Inkjet recording sheet &gt;.

<7> The ink jet recording sheet according to any one of <1> to <6>, wherein the color material receiving layer has a porosity of 40 to 80%.

<8> The inkjet recording sheet according to any one of <1> to <7>, wherein the mordant is a basic polymer.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the contents of the present invention will be described in detail.

<< Inkjet Recording Sheet >> The inkjet recording sheet of the present invention is an inkjet recording sheet having a colorant receiving layer containing inorganic pigment fine particles, a water-soluble resin and a mordant on the surface of the support. The surface of the body on which the colorant receiving layer is provided is subjected to an atmospheric pressure plasma treatment. Thereby, the adhesion between the support and the colorant receiving layer can be improved. In addition, the atmospheric pressure plasma treatment is suitable for a case where a support made of a material having low heat resistance is used because the amount of generated heat can be suppressed. Further, since the effect of the surface treatment is maintained for a long period of time, the adhesive force between the support and the colorant receiving layer is less reduced with time.

[Atmospheric Pressure Plasma Treatment] Atmospheric pressure plasma treatment applied to a support in the present invention will be described. The above-mentioned atmospheric pressure plasma treatment is a surface treatment of a support using plasma, and specifically, a treatment apparatus having electrodes facing each other and having at least one electrode surface coated with a solid dielectric. Introducing an inert gas or a mixed gas of an inert gas and a reactive gas into the apparatus under the atmospheric pressure or a pressure close to the atmospheric pressure, applying an AC voltage between the electrodes, and applying an atmospheric pressure glow. This is performed by exciting the discharge plasma and passing the support between the electrodes where the plasma is excited.

The configuration of the atmospheric pressure plasma processing apparatus will be described with reference to FIG. FIG. 1 is a schematic sectional view showing an example of the atmospheric pressure plasma processing apparatus. In FIG. 1, an atmospheric pressure plasma processing apparatus 10 has a pair of electrodes 12 and 14, and performs an atmospheric pressure plasma process by passing a support 16 as an object to be processed through a gap between the electrodes 12 and 14. At this time, the pressure in the atmospheric pressure plasma processing apparatus 10 is at or near atmospheric pressure. The electrodes 12, 14 are composed of electrode members 12a, 14a made of conductive metal and electrode members 12a, 14a.
and solid dielectrics 12b and 14b covering a part of a. One of the electrodes 12, 14 is a high-frequency power source (50 to
200 MHz), and the other electrode is grounded by ground, so that discharge is generated between the electrodes 12 and 14 to excite plasma. Further, an inert gas or a mixed gas composed of an inert gas and a reactive gas is introduced from a gas inlet 18 and discharged from a gas outlet 20. The atmospheric pressure plasma processing apparatus that can be used in the present invention is not limited to these configurations.

Each member of the atmospheric pressure plasma processing apparatus 10 will be described. The opposing electrodes 12 and 14 are flat,
It can take a form such as a cylindrical shape or a roll shape. The opposing electrodes 12 and 14 may have the same form, or may have different forms such as, for example, one having a flat plate shape and the other having a cylindrical shape. As the electrode members 12a and 14a constituting the electrodes 12 and 14, a conductive metal such as copper, stainless steel, and aluminum can be used. Also,
As the solid dielectrics 12b and 14b, rubber, glass, ceramic, polyimide, mica and the like can be used.
The electrode members 12a, 14a are entirely formed of solid derivatives 12b, 1
4b, or only a part thereof may be coated. The electrodes 12 and 14 are installed so as to be parallel to each other with a predetermined gap, and a support 16 as an object to be processed is transported between the electrodes by a transport means. If the gap between the electrodes exceeds 10 mm, the discharge becomes unstable, so the gap between the electrodes is preferably 10 mm or less. The voltage applied to the electrode is generally 1000 to
A voltage of 8000 V is employed. The discharge treatment density is preferably from 50 to 500 W · min / m ² . When the discharge treatment density is in the range of 50 to 500 W · min / m ² , the treatment can be performed uniformly, and further, the support /
The adhesive strength between the color material receiving layers is sufficiently improved, and the surface of the support is not deteriorated by damage received during processing.

Examples of the inert gas introduced into the atmospheric pressure plasma processing apparatus include argon gas, neon gas, helium gas, crimpton gas, and xenon gas.
Among them, argon gas, neon gas, and helium gas are preferable, and argon gas is particularly preferable in terms of processing effect and cost. The above inert gases may be used alone or as a mixture. When mixing argon gas with another inert gas, the ratio of argon gas is 5
0% by pressure or more is preferable, and 60% by pressure or more is more preferable.

A mixed gas of the above-mentioned inert gas and reactive gas can also be suitably used. When the reactive gas is mixed, the adhesive force between the support and the colorant receiving layer can be further improved by the chemically active groups generated by the plasma. Examples of the reactive gas include N ₂ , H ₂ , CO ₂ ,
CH ₂ , CO and the like. The mixed gas may be a mixture of two or more reactive gases. In the above mixed gas, the ratio of the reactive gas to the inert gas is preferably from 0.1 to 20% by volume, more preferably from 0.5 to 15% by volume. When using a mixed gas for the atmospheric pressure plasma treatment, it is preferable to mix an inert gas and a reactive gas in advance and introduce the mixed gas into the apparatus, but it is also possible to independently introduce each gas into the apparatus. It is sufficient that the atmosphere between the electrodes is a component of the mixed gas. In order to keep the inside of the device in a mixed gas atmosphere, it is preferable to provide a device for blocking air entering the device accompanying the support at the gas inlet and the gas outlet.

Preferably, the support is heated before the atmospheric pressure plasma treatment. When the support is subjected to an atmospheric pressure plasma treatment in a pre-heated state, the above-mentioned adhesive force can be improved in a short time treatment, and furthermore, yellowing, destruction, cracking, laceration on the pole surface, etc. can be greatly reduced. it can. The preheating temperature of the support is preferably within a range of ± 35% of the glass transition temperature of the support, and more preferably within a range of ± 20%.

[Support] As a material usable as the support, a transparent material such as plastic may be used.
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 materials include polyesters such as polyethylene terephthalate, nitrocellulose, cellulose acetate, or cellulose esters such as cellulose acetate butyrate, and polysulfone.
Examples thereof include polyphenylene oxide, polyimide, polycarbonate, and polyamide. Among these, polyesters are preferred, and polyethylene phthalate is particularly preferred. The thickness of the transparent support is not particularly limited, but a thickness of 50 to 200 μm is preferable because it is easy to handle.

The high gloss opaque support preferably has a glossiness of 40% or more on the surface on which the color material receiving layer is provided. The glossiness is JIS P-81
42 (75-degree specular gloss test method of paper and paperboard). Examples of high gloss opaque supports include art paper,
Coated paper, cast-coated paper, high gloss paper such as baryta paper used for silver salt photographic supports, polyesters such as polyethylene terephthalate (PET), nitrocellulose, cellulose acetate and cellulose acetate butyrate Cellulose esters, or polysulfone, polyphenylene oxide, polyimide,
High gloss (may be subjected to surface calendering, etc.) film made by adding a white pigment or the like to a plastic film such as polycarbonate or polyamide, or the above various papers, the above transparent plastic film or a plastic containing a white pigment or the like Examples of the support include a polyolefin coating layer containing a white pigment or not containing a white pigment on the surface of the film. Further, a foamed polyester film containing a white pigment (eg, foamed PET in which voids are formed by stretching and containing polyolefin fine particles) can also be mentioned.

A polyolefin-coated paper generally used as a silver salt photographic support (such as a paper support having a white pigment-containing polyolefin layer on its surface), or a special paper provided with a metal deposition layer or the like is provided. Paper or the like can be suitably used. In particular, a silver salt photographic paper support provided with a white pigment-containing polyolefin layer, a polyester (preferably PE) provided with a white pigment-containing polyolefin layer
T) A film, a white pigment-containing polyester film or a white pigment-containing foamed polyester film is preferred. The thickness of the opaque support is not particularly limited.
Those having a size of 0 to 300 μm are preferred because they are easy to handle.

[Coloring Material Receiving Layer] The ink jet recording sheet of the present invention has a coloring material receiving layer containing inorganic pigment fine particles, a water-soluble resin and a mordant. For this reason, when the inkjet recording sheet is folded or overlapped and handled, the color material receiving layer does not peel off from the support, that is, excellent handling properties are required to maintain performance such as ink receiving ability. Is important.

(Inorganic pigment fine particles) Examples of the inorganic pigment fine particles include silica fine particles, colloidal silica, titanium dioxide, barium sulfate, calcium silicate, zeolite, and the like.
Examples include kaolinite, halloysite, mica, talc, calcium carbonate, magnesium carbonate, calcium sulfate, boehmite, pseudo-boehmite and the like. Among them, silica fine particles are particularly preferable. Since the silica fine particles have a particularly large specific surface area, the ink absorbency, the efficiency of holding the ink is high, and the refractive index is low, so that it is possible to impart transparency to the colorant receiving layer by dispersing to an appropriate particle diameter. And high color density and good color developability. The fact that the colorant receiving layer is transparent means that not only applications requiring transparency such as OHP, but also high color density and good color developability when applied to recording sheets such as photo glossy paper. Is important.

The average primary particle diameter of the inorganic pigment fine particles is preferably 20 nm or less, more preferably 10 nm or less, and particularly preferably 3 to 10 nm.

The above silica fine particles have a silanol group on the surface, and the particles easily adhere to each other due to hydrogen bonding by the silanol group. Therefore, when the average primary particle diameter is 10 nm or less as described above, the porosity is large. A structure can be formed. Thereby, the ink absorption characteristics can be effectively improved.

The silica fine particles are roughly classified into wet-process particles and dry-process particles according to the production method. In the wet method, activated silica is generated by acid decomposition of silicate,
The mainstream method is to polymerize the mixture moderately and coagulate and settle to obtain hydrous silica. On the other hand, the dry method is a method by high-temperature gas phase hydrolysis of silicon halide (flame hydrolysis method), or a method in which silica sand and coke are heated and reduced by an arc in an electric furnace and oxidized by air. The method of obtaining anhydrous silica by (arc method) is the mainstream.

The hydrated silica and the anhydrous silica obtained by these methods have different properties due to differences in the density of silanol groups on the surface, presence or absence of vacancies, and the like. In particular, anhydrous silica (silicic anhydride) is preferable because it easily forms a three-dimensional structure having a high porosity. Although the reason is not clear, in the case of hydrous silica, the density of silanol groups on the surface of the fine particles is as large as 5 to 8 / nm ^2, and the silica fine particles are likely to be densely aggregated (aggregated). On the other hand, in the case of anhydrous silica, since the density of silanol groups on the surface of the fine particles is as small as ² to 3 / nm ² , sparse soft aggregation (flocculate) is obtained. As a result, it is assumed that the structure has a high porosity. Therefore, in the present invention, the density of silanol groups on the surface of the fine particles is 2 to 3 / nm.
It is preferable to use silica (silica fine particles) which is ² .

(Water-soluble resin) The water-soluble resin includes
For example, a resin having a hydroxyl group as a hydrophilic structural unit, such as polyvinyl alcohol (PVA), cation-modified polyvinyl alcohol, anion-modified polyvinyl alcohol, silanol-modified polyvinyl alcohol, polyvinyl acetal, a cellulose resin [methyl cellulose (MC), ethyl cellulose ( EC), hydroxyethylcellulose (HEC), carboxymethylcellulose (CMC), etc.], chitins, chitosans, starch; polyethylene oxide (PEO) which is a resin having an ether bond, polypropylene oxide (PP
O), polyethylene glycol (PEG), polyvinyl ether (PVE); polyacrylamide (PAAM), which is a resin having an amide group or an amide bond, and polyvinylpyrrolidone (PVP). Further, polyacrylates, maleic acid resins, alginates, and gelatins having a carboxyl group as a dissociable group can be exemplified. Among the above, polyvinyl alcohols are particularly preferred.

The content of the water-soluble resin is preferably from 9 to 40% by mass, more preferably from 16 to 33% by mass, based on the total solid mass of the colorant receiving layer. When the content is less than 9% by mass, the film strength is reduced, and cracks may easily occur during drying. When the content is more than 40% by mass, the voids are easily closed by the resin. And the ink absorbency may decrease.

The inorganic pigment fine particles and the water-soluble resin, which mainly constitute the color material receiving layer, may be a single material or a mixture of a plurality of materials.

Further, from the viewpoint of transparency, the type of resin to be combined with the silica fine particles is important. When the anhydrous silica is used, polyvinyl alcohol (PVA) is preferable as the water-soluble resin.
99% PVA is more preferable, and the degree of saponification is 70 to 90%.
Is particularly preferred.

The above-mentioned PVA has a hydroxyl group in its structural unit. The hydroxyl group and a silanol group on the surface of the silica fine particles form a hydrogen bond to form a three-dimensional network structure in which secondary particles of the silica fine particles are chain units. Easy to form. It is considered that the formation of the three-dimensional network structure can form a colorant receiving layer having a porous structure with a high porosity. In ink-jet recording, the porous colorant receiving layer obtained as described above can rapidly absorb ink by capillary action and form dots with good roundness without ink bleeding.

-Content ratio between inorganic pigment fine particles and water-soluble resin-Content ratio between inorganic pigment fine particles (preferably silica fine particles; i) and water-soluble resin (p) [PB ratio (i: p), water-soluble resin Mass of inorganic pigment fine particles with respect to 1 part by mass] greatly affects the film structure of the colorant receiving layer. That is, as the PB ratio increases, the porosity, the pore volume, and the surface area (per unit mass) increase. Specifically, the PB ratio (i: p)
Is preferably 1.5: 1 to 10: 1. The above PB
When the ratio exceeds 10: 1, that is, when the PB ratio is too large, the film strength is reduced, and cracks may easily occur during drying. When the ratio is less than 1.5: 1, that is, when the PB ratio is too small, As a result, the voids are more likely to be closed by the resin, and as a result, the porosity may decrease and the ink absorbency may decrease.

When the recording material passes through the transport system of the ink jet printer, stress may be applied to the recording sheet. Therefore, the color material receiving layer needs to have a sufficient film strength. Further, when the sheet is cut into a sheet, the color material receiving layer needs to have a sufficient film strength in order to prevent the color material receiving layer from cracking and peeling. In this case, the PB ratio is preferably 5: 1 or less, and is preferably 2: 1 or more from the viewpoint of securing high-speed ink absorption by an inkjet printer.

For example, anhydrous silica fine particles having an average primary particle diameter of 20 nm or less and a water-soluble resin are mixed with a PB ratio of 2: 1 to 5:
When a coating solution completely dispersed in an aqueous solution is coated on a support in 1 and the coating layer is dried, a three-dimensional network structure having secondary particles of silica fine particles as chain units is formed, and the average pore diameter is reduced. A light-transmitting porous film having a porosity of 30 nm or less, a porosity of 50% to 80%, a specific pore volume of 0.5 ml / g or more, and a specific surface area of 100 m ² / g or more can be easily formed.

(Mordant) In the present invention, a mordant is contained in the colorant receiving layer from the viewpoint of further improving the water resistance and aging resistance of the formed image. The mordant is a cationic basic polymer (hereinafter, sometimes referred to as a “cationic mordant”), and is present in a colorant receiving layer to form a liquid with an anionic dye as a colorant. The colorants can interact with each other to stabilize the coloring material, thereby improving water resistance and bleeding over time.

However, if this is added directly to the coating solution for forming the colorant receiving layer, there is a possibility that aggregation may occur with inorganic pigment fine particles having an anionic charge such as silica. If the method of preparing and applying the solution as another solution is used, there is no need to worry about aggregation of the inorganic pigment fine particles. Therefore, in the present invention, it is preferable to use it in a crosslinking agent solution described below.

As the above-mentioned cationic mordant, a polymer mordant having a primary to tertiary amino group or a quaternary ammonium group as a cationic group is preferably used, but a cationic non-polymer mordant is also used. can do. The above-mentioned polymer mordants include primary to tertiary
Homopolymer of a monomer having a quaternary amino group and a salt thereof, or a quaternary ammonium salt group (mordanting monomer), or a copolymer of the mordanting monomer and another monomer (hereinafter, referred to as “non-mordanting polymer”). Those obtained as a combined or condensed polymer are preferred. These polymer mordants can be used in the form of either a water-soluble polymer or water-dispersible latex particles.

Examples of the above monomers (mordanting monomers) include trimethyl-p-vinylbenzylammonium chloride, trimethyl-m-vinylbenzylammonium chloride, triethyl-p-vinylbenzylammonium chloride, and triethyl-m-vinylbenzylammonium. Chloride, N, N-dimethyl-N-ethyl-Np-vinylbenzylammonium chloride,
N, N-diethyl-N-methyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-Nn
-Propyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-Nn-octyl-Np
-Vinylbenzylammonium chloride, N, N-dimethyl-N-benzyl-Np-vinylbenzylammonium chloride, N, N-diethyl-N-benzyl-
Np-vinylbenzylammonium chloride, N,
N-dimethyl-N- (4-methyl) benzyl-Np-
Vinylbenzylammonium chloride, N, N-dimethyl-N-phenyl-Np-vinylbenzylammonium chloride,

Trimethyl-p-vinylbenzylammonium bromide, trimethyl-m-vinylbenzylammonium bromide, trimethyl-p-vinylbenzylammonium sulfonate, trimethyl-m-vinylbenzylammonium sulfonate, trimethyl-p-vinylbenzylammonium acetate, trimethyl- m
-Vinylbenzylammonium acetate, N, N, N
-Triethyl-N-2- (4-vinylphenyl) ethylammonium chloride, N, N, N-triethyl-N
-2- (3-vinylphenyl) ethylammonium chloride, N, N-diethyl-N-methyl-N-2- (4
-Vinylphenyl) ethylammonium chloride,
N, N-diethyl-N-methyl-N-2- (4-vinylphenyl) ethylammonium acetate;

N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth)
Acrylate, N, N-diethylaminopropyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylamide, N, N-diethylaminoethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N, N Methyl chloride of N-diethylaminopropyl (meth) acrylamide,
Examples include ethyl chloride, methyl bromide, ethyl bromide, a quaternary compound of methyl iodide or ethyl iodide, or a sulfonate, alkyl sulfonate, acetate or alkyl carboxylate in which an anion thereof is substituted.

Specifically, for example, trimethyl-2-
(Methacryloyloxy) ethylammonium chloride, triethyl-2- (methacryloyloxy) ethylammonium chloride, trimethyl-2- (acryloyloxy) ethylammonium chloride, triethyl-2- (acryloyloxy) ethylammonium chloride, trimethyl-3- (methacryloyl) Oxy)
Propyl ammonium chloride, triethyl-3-
(Methacryloyloxy) propyl ammonium chloride, trimethyl-2- (methacryloylamino) ethylammonium chloride, triethyl-2- (methacryloylamino) ethylammonium chloride, trimethyl-2- (acryloylamino) ethylammonium chloride, triethyl-2- (acryloyl) Amino) ethylammonium chloride, trimethyl-3-
(Methacryloylamino) propylammonium chloride, triethyl-3- (methacryloylamino) propylammonium chloride, trimethyl-3- (acryloylamino) propylammonium chloride, triethyl-3- (acryloylamino) propylammonium chloride,

N, N-dimethyl-N-ethyl-2- (methacryloyloxy) ethylammonium chloride,
N, N-diethyl-N-methyl-2- (methacryloyloxy) ethylammonium chloride, N, N-dimethyl-N-ethyl-3- (acryloylamino) propylammonium chloride, trimethyl-2- (methacryloyloxy) ethylammonium Bromide, trimethyl-3- (acryloylamino) propylammonium bromide, trimethyl-2- (methacryloyloxy) ethylammonium sulfonate, trimethyl-
3- (acryloylamino) propyl ammonium acetate and the like can be mentioned. In addition, as copolymerizable monomers, N-vinylimidazole, N-vinyl-2-methylimidazole and the like can also be mentioned.

The above non-mordanting polymer does not contain a basic or cationic moiety such as a primary to tertiary amino group and a salt thereof, or a quaternary ammonium base, and has an interaction with a dye in an inkjet ink. A monomer that does not show or has substantially small interaction. Examples of the non-mordanting monomer include (meth) acrylic acid alkyl ester; (meth) acrylic acid cycloalkyl ester such as (meth) acrylic acid cyclohexyl;
Aryl (meth) acrylates such as phenyl acrylate; aralkyl esters such as benzyl (meth) acrylate; aromatic vinyls such as styrene, vinyl toluene and α-methylstyrene; vinyl acetate, vinyl propionate, and vinyl versatate Vinyl esters such as allyl acetate; halogen-containing monomers such as vinylidene chloride and vinyl chloride; vinyl cyanide such as (meth) acrylonitrile; and olefins such as ethylene and propylene.

The above (meth) acrylic acid alkyl ester includes (meth) acrylic acid having 1 to 18 carbon atoms in the alkyl moiety.
Alkyl acrylates are preferred, for example, methyl (meth) acrylate, ethyl (meth) acrylate,
Propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate,
Examples include hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, and stearyl (meth) acrylate. Among them, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, and hydroxyethyl methacrylate are preferred. The above non-mordanting monomers can be used alone or in combination of two or more.

Further, as a polymer mordant, polydiallyldimethylammonium chloride, polymethacryloyloxyethyl-β-hydroxyethyldimethylammonium chloride, polyethyleneimine, polyallylamine, polyallylamine hydrochloride, polyamide-polyamine resin, cationized starch, dicyandiamide Formalin condensate, dimethyl-2-hydroxypropylammonium salt polymer, polyamidine, polyvinylamine and the like can also be mentioned as preferable ones.

The molecular weight of the polymer mordant is 1
000 to 200,000 is preferred. The molecular weight is 100
If it is less than 0, the water resistance tends to be insufficient, and 2
If it exceeds 00000, the viscosity may be too high and the handling adequacy may decrease.

As the cationic non-polymer mordant, for example, water-soluble metal salts such as aluminum sulfate, aluminum chloride, polyaluminum chloride and magnesium chloride are preferable.

(Crosslinking Agent) In the ink jet recording sheet of the present invention, it is preferable that a crosslinking agent capable of crosslinking the water-soluble resin is further used in combination with the colorant receiving layer.

The cross-linking agent solution is applied at the same time as when the coating solution for forming the porous color material receiving layer (coating solution for the color material receiving layer) is applied, or when the coating solution for the color material receiving layer is applied. It is preferable that the coating be performed before the coating layer formed by coating exhibits a reduced drying rate. By this operation, it is possible to effectively prevent the occurrence of cracks generated during drying of the coating layer. That is, the cross-linking agent solution permeates into the coating layer at the same time as when the coating liquid is applied or before the coating layer exhibits a reduced drying rate, and quickly reacts with the water-soluble resin in the coating layer, By gelling (curing) the water-soluble resin, the film strength of the coating layer is immediately and greatly improved.

As a crosslinking agent capable of crosslinking the above water-soluble resin,
Is suitable in relation to the water-soluble resin used for the colorant receiving layer.
The cross-linking reaction is particularly rapid.
In view of the following, a boron compound is preferable, for example,
Sand, boric acid, borate (eg, orthoborate, In
BO_Three, ScBO_Three, YBO_Three, LaBO_Three, Mg_Three(BO _Three)
_Two, Co_Three(BO_Three)_Two, Diborate (eg, Mg_TwoB
_TwoO_Five, Co_TwoB_TwoO_Five), Metaborate (eg, LiB
O_Two, Ca (BO_Two)_Two, NaBO_Two, KBO_Two), Tetraboric acid
Salt (eg, Na_TwoB_FourO₇・ 10H_TwoO), pentaborate
(For example, KB_FiveO₈・ 4H_TwoO, Ca_TwoB₆O₁₁・ 7H
_TwoO, CsB_FiveO_Five), Glyoxal, melamine phor
Mualdehyde (eg, methylolmelamine, alkyl
Methylol melamine), methylol urea, resole tree
Fats, polyisocyanates, epoxy resins, etc.
Can be. Among them, e.
Grain, boric acid, borate are preferred, especially with water-soluble resins.
Used in combination with polyvinyl alcohol
Is more preferred.

When gelatin is used as the water-soluble resin, the following compounds known as gelatin hardeners can be used as a crosslinking agent. For example, aldehyde compounds such as formaldehyde, glyoxal, and glutaraldehyde; ketone compounds such as diacetyl and cyclopentanedione; bis (2-chloroethylurea) -2-hydroxy-4,6-dichloro-1,3;
Active halogen compounds such as 5-triazine and 2,4-dichloro-6-S-triazine sodium salt; divinylsulfonic acid, 1,3-vinylsulfonyl-2-propanol, N, N′-ethylenebis (vinylsulfonylamine) Active vinyl compounds such as cetamide), 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; US Patent No. 301
Nos. 7280 and 29836311; aziridine compounds; carboximide compounds described in U.S. Pat. No. 3,100,704; epoxy compounds such as glycerol triglycidyl ether; 1,6-hexamethylene-N, N ' Ethyleneimino compounds such as bisethyleneurea; halogenated carboxaldehyde compounds such as mucochloric acid and mucophenoxycyclolic acid; dioxane compounds such as 2,3-dihydroxydioxane; chromium alum, potassium alum, zirconium sulfate; Chromium acetate and the like. The crosslinking agent may be used alone or in combination of two or more.

The above crosslinking agent solution 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 set at 0.1 to the mass of the cross-linking agent solution.
It is preferably from 0.05 to 10% by mass, particularly preferably from 0.1 to 7% by mass. As a solvent constituting the crosslinking agent solution, water is generally used, and an aqueous mixed solvent containing an organic solvent miscible with the water may be used. Any organic solvent can be used as long as it can dissolve the crosslinking agent. Examples thereof include alcohols such as methanol, ethanol, isopropyl alcohol, and glycerin; ketones such as acetone and methyl ethyl ketone; methyl acetate and ethyl acetate. Esters; aromatic solvents such as toluene; ethers such as tetrahydrofuran; and halogenated carbon-based solvents such as dichloromethane.

(Other Additives) The ink jet recording sheet of the present invention may further contain the following components, if necessary. For the purpose of suppressing the deterioration of the coloring material, it may contain various ultraviolet absorbers, antioxidants, and anti-fading agents such as singlet oxygen quencher. Examples of the ultraviolet absorber include cinnamic acid derivatives, benzophenone derivatives, and benzotriazolylphenol derivatives. For example, α-cyano-phenyl butyl cinnamate, o-
Benzotriazole phenol, o-benzotriazole-p-chlorophenol, o-benzotriazole-
2,4-di-t-butylphenol, o-benzotriazole-2,4-di-t-octylphenol and the like can be mentioned. A hindered phenol compound can also be used as an ultraviolet absorber, and specifically, a phenol derivative in which at least one of the 2- and 6-positions is substituted with a branched alkyl group is preferable.

Further, a benzotriazole-based UV absorber, a salicylic acid-based UV absorber, a cyanoacrylate-based UV absorber, an oxalic acid anilide-based UV absorber, and the like can also be used. For example, JP-A-47-1053
No. 7, No. 58-111942, No. 58-21
Nos. 2844, 59-19945 and 59-
Nos. 46646, 59-109055 and 6
JP-A-3-53544, JP-B-36-10466, JP-A-42-26187, JP-A-48-30492, JP-A-48-31255, JP-A-48-41572.
JP-A-48-54965, JP-A-50-1072
No. 6, US Pat. No. 2,719,086, US Pat. No. 3,707,375, US Pat. No. 3,754,919, US Pat. No. 4,220,711, and the like. I have.

A fluorescent whitening agent can also be used as an ultraviolet absorber, and examples thereof include a coumarin fluorescent whitening agent. Specifically, Japanese Patent Publication Nos. 45-4699 and 54-53
No. 24, and the like.

Examples of the antioxidant include EP-A-223239, JP-A-309401, JP-A-309402, JP-A-310551, and JP-A-31551.
Nos. 0552 and 594416, German Patent No. 3435443, and JP-A-54-48535.
JP-A-60-107384 and JP-A-60-107384
No. 383, No. 60-125470, No. 60-125
No. 125471, No. 60-125472, No. 60-287485, No. 60-287486, No. 60-287487, No. 60-28748.
No. 8, No. 61-160287, No. 61-18
Nos. 5483, 61-211079 and 62
-146678, 62-146680,
JP-A-62-146679, JP-A-62-282885, JP-A-62-262047, and JP-A-63-0511
Nos. 74, 63-89877 and 63-88
Nos. 380, 66-88381, 63-1
No. 13536,

Nos. 63-163351 and 63-2
03372, 63-224989, 6
JP-A-3-251282, JP-A-63-267594, JP-A-63-182484, JP-A-1-23992
No. 82, JP-A-2-262654, JP-A-2-7
No. 1262, No. 3-121449, No. 4-2
Nos. 91686, 4-291684, 5-
Nos. 61166, 5-119449, 5-
188687, 5-18886, 5
No. 110490, No. 5-1108437,
No. 5-170361, JP-B-48-43295, JP-B-48-33212, U.S. Pat.
No. 262, No. 4,980,275 and the like.

Specifically, 6-ethoxy-1-phenyl-2,2,4-trimethyl-1,2-dihydroquinoline, 6-ethoxy-1-octyl-2,2,4-trimethyl-1,2 -Dihydroquinoline, 6-ethoxy-1-
Phenyl-2,2,4-trimethyl-1,2,3,4-
Tetrahydroquinoline, 6-ethoxy-1-octyl-
2,2,4-trimethyl-1,2,3,4-tetrahydroquinoline, nickel cyclohexanoate, 2,2-bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) -2 -Ethyl hexane, 2
-Methyl-4-methoxy-diphenylamine, 1-methyl-2-phenylindole and the like.

The anti-fading agents may be used alone or in combination of two or more. The anti-fading agent may be made water-soluble, dispersed, or emulsified, or may be contained in microcapsules. The amount of the anti-fading agent to be added is preferably 0.01 to 10% by mass of the coating material for the colorant receiving layer.

Further, in order to enhance the dispersibility of the inorganic pigment fine particles, various inorganic salts and acids or alkalis as pH adjusters may be contained. In addition, various surfactants are used for the purpose of improving coating suitability and surface quality, and surfactants having ionic conductivity and metal oxide fine particles having electronic conductivity are used for the purpose of suppressing triboelectric charging and peeling charging of the surface. In addition, various matting agents may be included for the purpose of reducing the friction characteristics of the surface.

[Method of Producing Ink-Jet Recording Sheet] As described above, it is preferable that a mordant and a cross-linking agent are introduced into the colorant receiving layer during the process of applying the cross-linking agent solution. That is, the colorant receiving layer is a coating solution containing inorganic pigment fine particles and a water-soluble resin (an organic solvent may be used in combination with water as appropriate. In some cases, the coating solution is hereinafter referred to as a “first coating solution”). And (1) simultaneously with the application, or (2)
A solution containing a cross-linking agent and a mordant capable of cross-linking the water-soluble resin in the coating layer before drying the coating layer at a reduced drying rate during the drying of the coating layer formed by the coating. (Hereinafter, it may be referred to as “second coating liquid”.)
Is preferably formed by a method (WOW method; Wet OnWet method) of crosslinking and curing the coating layer provided with the solution.

The colorant receiving layer of the ink jet recording sheet of the present invention comprises a coating solution containing fine inorganic pigment particles and a water-soluble resin, and a solution containing a crosslinking agent. (However, a mordant may be contained in at least one of the solution containing a crosslinking agent or the barrier liquid.) It can also be obtained by simultaneously applying the mixture on a support in a state where it is sandwiched and curing.

As described above, in the present invention, the water resistance of the colorant receiving layer is improved by simultaneously applying the mordant together with the crosslinking agent. That is, when the mordant is added to the first coating solution, the mordant is cationic,
Agglomeration may occur in the presence of inorganic pigment fine particles having an anionic charge on the surface, such as silica, but a method in which a solution containing a mordant and the first coating solution are independently prepared and individually applied. By employing the above, it is not necessary to consider the aggregation of the inorganic pigment fine particles, and the selection range of the mordant is widened.

In the present invention, the first coating solution for the colorant receiving layer (coating solution for the colorant receiving layer) comprising at least inorganic pigment fine particles and a water-soluble resin is prepared, for example, as follows. it can. That is, silica fine particles having an average primary particle diameter of 20 nm or less are added to water (for example, 10 to 20% by mass), and a high-speed rotating wet colloid mill (for example, CLEARMIX (manufactured by M Technique Co., Ltd.)) is used. , For example, 10,000 rpm (preferably 5000 to 20,000
rpm) for 20 minutes (preferably 10 rpm).
After dispersion, a polyvinyl alcohol aqueous solution (for example, PVA having a mass of about 1/3 of silica) is added, and the dispersion is further performed under the same rotation conditions as described above. . The obtained coating solution is a uniform sol, and by coating this on a support by the following coating method, a porous colorant receiving layer having a three-dimensional network structure can be formed. If necessary, a surfactant, a pH adjuster, an antistatic agent and the like can be further added to the first coating liquid.

The first coating solution can be applied 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 applying the first coating solution, a second solution (crosslinking agent solution) containing a crosslinking agent and a mordant is applied to the coating layer. The second coating solution is applied after the application. It may be applied before the layer exhibits a reduced drying rate. That is,
After the application of the first coating solution, the coating layer is suitably manufactured by introducing a crosslinking agent and a mordant while the coating layer exhibits a constant rate of drying. Here, “before the coating layer exhibits a reduced drying rate” usually refers to a few minutes immediately after the application of the first coating solution, during which time the solvent in the applied coating layer is It shows a constant rate drying rate, a phenomenon in which the content decreases in proportion to time. For the time indicating the constant rate drying rate,
Chemical Engineering Handbook (pp. 707-712, published by Maruzen Co., Ltd.
(October 25, 1980).

As described above, after the application of the first coating solution, the coating layer is dried until the coating layer exhibits a reduced rate drying rate. The drying is generally performed at 50 to 180 ° C. for 0.5 to 10 minutes. (Preferably for 0.5 to 5 minutes). The drying time varies depending on the coating amount, but the above range is appropriate.

As a method of applying the coating layer before the coating layer exhibits a reduced rate of drying, (1) a method of further applying a second coating liquid onto the coating layer, and (2) a method such as spraying. A method of spraying, and (3) a method of immersing the support on which the coating layer is formed in a second coating liquid.

In the above method (1), the coating method for applying the second coating solution includes, for example, a curtain flow coater, an extrusion die coater, an air doctor coater, a bread coater, a rod coater, a knife coater, a squeeze coater, and a reverse roll. Known coating methods such as a coater and a bar coater can be used. However, it is preferable to use a method such as an extrusion die coater, a curtain flow coater, a bar coater, etc., in which the coater does not directly contact the already formed coating layer.

The coating amount of the second coating solution (crosslinking agent solution) containing at least a crosslinking agent and a mordant applied on the colorant receiving layer is 0.01 to 10 g / m ^{2 in} terms of a crosslinking agent.
Is general, and 0.05 to 5 g / m ² is preferable.

After the application of the second coating liquid, generally, 40 to 1
Heat at 80 ° C. for 0.5 to 30 minutes to dry and cure. Especially, it is preferable to heat at 40 to 150 ° C. for 1 to 20 minutes. For example, when borax or boric acid is used as the crosslinking agent contained in the second coating solution, it is preferable to perform heating at 60 to 100 ° C. for 5 to 20 minutes.

The second coating liquid may be applied simultaneously with the application of the first coating liquid. In this case, the first coating liquid and the second coating liquid containing the cross-linking agent and the mordant,
The colorant receiving layer can be formed by simultaneously applying (multilayer coating) the support onto the support such that the first coating solution comes into contact with the support, and then drying and curing.

The simultaneous coating (multilayer coating) can be performed by a coating method using, for example, an extrusion die coater or a curtain flow coater. After the simultaneous coating, the formed coating layer is dried. In this case, the drying is generally performed by heating the coating layer at 40 to 150 ° C. for 0.5 to 10 minutes, preferably 40 to 150 ° C.
It is performed by heating at 100 ° C. for 0.5 to 5 minutes. For example, when borax or boric acid is used as a cross-linking agent contained in the second coating solution,
It is preferred to heat for 20 minutes.

When the simultaneous coating (multi-layer coating) is performed by, for example, an extrusion die coater, the two kinds of coating liquids simultaneously discharged are close to the discharge port of the extrusion die coater, that is, before being transferred onto a support. A multilayer is formed, and in that state, a multilayer coating is performed on a support. When the two-layer coating solution, which has been layered before coating, is transferred to the support, a crosslinking reaction is likely to occur at the interface between the two components, so the two components to be discharged are mixed near the discharge port of the extrusion die coater. And the viscosity increases, which may hinder the application operation. Therefore, when the two layers are simultaneously coated as described above, the first coating liquid and the second coating liquid containing a cross-linking agent and a mordant are applied together with a barrier layer liquid (intermediate layer) made of a material that does not react with the cross-linking agent. Liquid) is preferably interposed between the two liquids for simultaneous three-layer coating.

The barrier layer solution can be selected without any particular limitation as long as it can form a liquid film without reacting with the crosslinking agent. For example, an aqueous solution containing a trace amount of a water-soluble resin that does not react with the crosslinking agent, water, or the like can be used. The water-soluble resin is used in consideration of applicability for the purpose of a thickener and the like, for example, hydroxypropyl methyl cellulose,
Methyl cellulose, hydroxyethyl methyl cellulose
And polymers such as polyvinylpyrrolidone and gelatin. Incidentally, the mordant may be contained in the barrier layer liquid.

After the color material receiving layer is formed on the support, the color material receiving layer is calendered through a roll nip under heat and pressure using, for example, a super calendar, a gloss calendar, etc. It is possible to improve the properties, glossiness, transparency and coating strength. However, since the calendering process may cause a decrease in the porosity (that is, the ink absorbency may be reduced), it is necessary to set a condition under which the porosity does not decrease much.

The roll temperature for calendering is preferably 30 to 150 ° C., and 40 to 100 ° C.
C is more preferred. Further, the linear pressure between the rolls during the calendering process is preferably 50 to 400 kg / cm,
100-200 kg / cm is more preferable.

In the case of ink jet recording, the layer thickness of the color material receiving layer needs to have an absorption capacity to absorb all the liquid droplets, and thus needs to be determined in relation to the porosity in the layer. is there. For example, if the ink amount is 8 nL / mm ²
If the porosity is 60%, the layer thickness is about 15 μm.
The above film is required. Considering this point, in the case of inkjet recording, the layer thickness of the colorant receiving layer is 1
0 to 50 μm is preferred.

The pore diameter of the colorant receiving layer is preferably from 0.005 to 0.030 μm in terms of median diameter, and from 0.01 to 0.030 μm.
0.025 μm is more preferred. The porosity and the median pore diameter can be measured using a mercury porosimeter (trade name: Pore Sizer 9320-PC2, manufactured by Shimadzu Corporation).

The color material receiving layer is preferably excellent in transparency. As a rule, the haze value when the color material receiving layer is formed on a transparent film support is 30%.
% Or less, and more preferably 20% or less. The haze value is measured with a haze meter (HG
M-2DP: Suga Test Instruments Co., Ltd.).

An undercoat layer may be provided on the support for the purpose of increasing the adhesiveness between the colorant receiving layer and the support, adjusting the electric resistance, and the like. The color material receiving layer may be provided on only one side of the support, or may be provided on both sides of the support for the purpose of suppressing deformation such as curling. OH
In the case of using P or the like, when the colorant receiving layer is provided on only one surface of the support, an antireflection film can be provided on the opposite surface, or on both surfaces, for the purpose of enhancing light transmittance. .

Further, a boric acid or a boron compound is coated on the surface of the support on which the color material receiving layer is formed, and the color material receiving layer is formed on the surface, whereby the glossiness of the color material receiving layer is improved. In addition, the surface smoothness can be ensured, and blurring with time of an image after printing in a high-temperature and high-humidity environment can be suppressed. In addition, the colorant receiving layer has a three-dimensional network structure having a porosity of 50 to 80% containing inorganic pigment fine particles, exhibits good ink absorbency, and can form a high-resolution and high-density image. Excellent ink receiving performance such as high light resistance and high water resistance can be secured.

[0099]

Hereinafter, the present invention will be described with reference to Examples.
The present invention is not limited to these examples.
In the examples, “parts” and “%” are all “parts by mass”.
And "% by mass".

Example 1 Preparation of Support A standard corona discharge treatment was applied to the wire (rear surface) side of a base paper having a weight of 159 g / m ² , a thickness of 187 μm, and a whiteness of 82%, and then a melt extruder. Then, high-density polyethylene was coated to a thickness of 20 μm to form a resin layer composed of a mat surface (hereinafter, the resin layer surface is referred to as “back surface”). After further performing a normal corona discharge treatment on the resin layer on the back surface side, aluminum oxide (alumina sol 100, manufactured by Nissan Chemical Industries, Ltd.) and silicon dioxide (Snowtex O, Nissan Chemical Industries, Ltd.) were used as antistatic agents. )
Was dispersed in water at a ratio (mass ratio) of 1: 2, and was applied so that the dry weight was 0.2 g / m ² . Next, the felt surface (surface) on the side where the resin layer is not provided
After corona discharge treatment on the side, anatase type titanium dioxide 10%, trace amount of ultramarine blue, and fluorescent whitening agent 0.01%
(Relative to polyethylene), low density polyethylene having a melt flow rate (MFR) of 3.8 was melt-extruded using a melt extruder to a thickness of 25 μm, and a high-gloss thermoplastic resin layer was formed on the base paper. It was formed on the front surface side (hereinafter, this high gloss surface is referred to as "front surface") to provide a support.

-Preparation of Coating Solution (a) for Coloring Material Receptive Layer- (1) and (2) in the following composition were mixed, and a high-speed rotating colloid mill (CLEARMIX, manufactured by M Technic Co., Ltd.) was used. After dispersing at 10,000 rpm for 20 minutes, the following (3) polyvinyl alcohol 9%
The following components (4) to (8) were added together with the aqueous solution, and the mixture was dispersed under the same conditions as above to prepare a coating material for a colorant receiving layer. Mass ratio of silica fine particles to water-soluble resin (P
B ratio) was 3.5: 1.

[Composition of Colorant Receptive Layer Coating Solution (a)] (1) 9.9 parts of inorganic pigment fine particles (vapor-phase silica) (average primary particle diameter: 7 nm; Aerosil 300, manufactured by Nippon Aerosil Co., Ltd.) 2) 72.6 parts of ion-exchanged water (3) 31.4 parts of a 9% aqueous solution of polyvinyl alcohol (water-soluble resin) (PVA420, manufactured by Kuraray Co., Ltd., degree of saponification 81.8%, degree of polymerization 2000) (4) 1N Ammonia water (pH adjuster) 5.3 parts (5) Emulgen 109P (10%, manufactured by Kao Corporation) 7.2 parts (surfactant; polyoxyethylene lauryl ether, HLB 13.6) (6) N -Methylpyrrolidone 0.6 part (7) n-butanol 0.6 part (8) diethylene glycol monobutyl ether 0.6 part

-Preparation of Sheet for Ink-Jet Recording of the Present Invention-
Voltage: 6 kV, working gas: Ar: He: CO (7: 3: 0.
5) Atmospheric pressure plasma treatment was performed on the surface of the support under the condition of a discharge amount of 200 W · min / m ² . Next, the coating material for the colorant receiving layer obtained above was applied to the above support at an application amount of 200 ml / m ² using an extrusion die coater (application step), and was heated to 80 ° C. (wind speed) using a hot air drier. The coating was dried at a rate of 3 to 8 m / sec until the solid content concentration of the coating layer became 20%. The coating layer exhibited a constant rate of drying during this period. Immediately thereafter, it was immersed in a coating solution (crosslinking agent-containing solution (a)) having the following composition for 30 seconds, and 20 g of the solution was coated on the coating layer.
/ M ² (step of applying the crosslinking agent-containing solution (a)), and then further dried at 80 ° C. for 10 minutes (drying step). As a result, a color material receiving layer having a dry film thickness of 32 μm was formed on the support, and an ink jet recording sheet of the present invention was produced.

<Composition of Crosslinking Agent-Containing Solution (a)> (1) 25% of 6% boric acid (crosslinking agent) (2) PAS-F5000 (20%; mordant 7.15 parts) (3) Emulgen 109P (10% 2 parts (surfactant; polyoxyethylene lauryl ether, HLB 13.6) (4) Ammonium chloride (surface pH adjuster) 0.2 part (5) 25% ammonia water (pH adjustment) 1.67 parts (6) Deionized water 68.98 parts

(Evaluation Method) (1-1) Gloss 60 ° on the surface of the colorant receiving layer of the recording sheet before printing
The gloss was measured using a digital variable-angle gloss meter (UGV-50DP,
(Manufactured by Suga Test Instruments Co., Ltd.).

(1-2) Ink Absorption Speed Using an ink jet printer (PM-770C, manufactured by Seiko Epson Corporation), ink jet recording sheets were coated with Y (yellow), M (magenta), C (cyan), K
(Black), B (Blue), G (Green) and R (Red) solid images are printed, and immediately thereafter (after about 10 seconds), paper is contact-pressed on the images, and ink is applied to the paper. The presence or absence of transfer was evaluated according to the following criteria. [Criterion] AA: No transfer of ink to paper was observed at all.
This indicates that the ink absorption speed is good. CC: Partial transfer of ink on paper was observed.

(1-3) Water resistance Using the same printer as in the above (1-2), the same printing pattern was formed on the ink jet recording sheet, left for 3 hours, immersed in water for 1 minute, Was visually observed and evaluated according to the following criteria. [Criterion] AA: No outflow of dye was observed. BB: The part where the dye had flowed out was observed, and the color density was lowered. CC: The dye has almost completely flowed into the water.

(1-4) Time-lapse bleeding Using the same printer as in the above (1-2), a grid-like linear pattern (line width 0. 0) in which magenta ink and black ink are arranged side by side on an ink jet recording sheet. 2
8 mm). After leaving for 3 hours after printing, 40
The sample was stored in a thermo-hygrostat at 90 ° C. and a relative humidity of 90% for 3 days, the line width of the black portion was measured, and evaluated according to the following criteria. [Criterion] AA: Almost no occurrence of bleeding over time was observed, and it was good. (Line width: 0.28 to 0.30 mm) BB: Although slight bleeding with time was observed, the level was not a problem in practical use. (Line width: 0.31 to 0.35 mm) CC: Time-dependent bleeding was remarkably recognized, which was at a practically problematic level. (Line width: 0.35 or more)

(1-5) Light fastness Using the same printer as in the above (1-2), Y (yellow), M
(Magenta), C (cyan), K (black), B (blue), G
After printing solid images of (green) and R (red), 365
through a film that cuts ultraviolet light in the wavelength range of less than 10 nm, using a Xenonweather-meter Ci
Using a 65A (manufactured by ATLAS), the lamp was turned on for 3.8 hours under an environmental condition of 25 ° C. and a relative humidity of 32%, and then, with the lamp turned off, at an ambient condition of 20 ° C. and a relative humidity of 91%. A cycle of allowing the sample to stand for 1 hour was performed for 96 hours, and the degree of fading of each color density of the image was visually evaluated according to the following criteria. [Criteria] A: Almost no fading was observed. O: Slight fading was observed. Δ: considerable fading was observed. X: The degree of fading was remarkable.

(Image Density) Using the same printer as in (1-2) above, a black solid image was printed on a recording sheet, and the reflection density was measured with an X-Rite310TR (manufactured by X-Rite).

(Handleability) A test piece was prepared by cutting the ink jet recording sheet to a width of 25 mm and a length of 100 mm. The test piece was bent so that the color material receiving layer was positioned outside, and the bent portion was rubbed with a finger, and the degree of peeling of the color material receiving layer was evaluated according to the following criteria. [Criterion] A: Peeling of the colorant receiving layer was not observed at all. ×: Slight peeling was observed, but at a level that was not problematic in practical use. Δ: Peeling was observed. X: Remarkable peeling was observed.

(Workability) The degree of peeling of the colorant receiving layer from the support when the ink jet recording sheet manufactured in a long shape was cut into a desired shape using a guillotine cutter was visually determined as follows. It was evaluated according to the standard. [Criteria] ○: No peeling of the colorant receiving layer was observed. ×: Slight peeling was observed, but at a level that was not problematic in practical use. Δ: Peeling was observed. ×: Remarkable peeling was observed.

Table 1 below shows the results of these evaluations.

[Embodiment 2] In the embodiment 1, the conditions of the atmospheric plasma treatment were as follows: the interelectrode gap was 10 mm, the voltage was 4 kV.
An ink jet recording sheet was prepared and evaluated in the same manner as in Example 1, except that the gas used was Ar: He: CO (7: 3: 0.5) and the discharge amount was changed to 100 W · min / m ² . . The results are shown in Table 1 below.

Comparative Example 1 The procedure of Example 1 was repeated, except that the surface of the support was subjected to a corona discharge treatment at a discharge rate of 200 W · min / m ² instead of the atmospheric plasma treatment. In this way, an ink jet recording sheet was prepared and evaluated in the same manner. The results are shown in Table 1 below.

(Example 3) Instead of the coating material (a) for the colorant receiving layer used in Example 1, a coating solution (b) for the colorant receiving layer prepared as described below was used. ) Was changed to the composition of the following crosslinking agent solution (b), and the conditions of the atmospheric plasma treatment were as follows: gap between electrodes: 7 mm; voltage: 6 kV;
r: He: CO ₂ (7: 3: 0.5), discharge amount 200W
An ink jet recording sheet was prepared and evaluated in the same manner as in Example 1 except that the value was changed to min / m ² . The results are shown in Table 1 below.

-Preparation of Coating Solution (b) for Coloring Material Receiving Layer- (1) and (2) in the following composition were mixed, and a high-speed rotating colloid mill (CLEARMIX, manufactured by M Technique Co., Ltd.) was used. After dispersing at 10,000 rpm for 20 minutes, the following (3) was added thereto, and the following components (4) to (8) were further added. A coating solution for a receiving layer was prepared. The mass ratio (PB ratio) between the silica fine particles and the water-soluble resin is 3.5: 1.
Met.

[Composition of Coloring Material Receptive Layer Coating Solution (b)] (1) Inorganic Pigment Fine Particles (Silica by Vapor Phase) 100 parts (Average Primary Particle Diameter 7 nm; Leolosil QS30, manufactured by Tokuyama Corporation) (2) Ion Exchanged water 558 parts (3) Polyvinyl alcohol 7% aqueous solution (water-soluble resin) 318 parts (PVA124, manufactured by Kuraray Co., Ltd., saponification degree 98.5%, polymerization degree 2400) (4) PAS-M1 (dispersant (60 8.3 parts (5) Emulgen 109P (10%, manufactured by Kao Corporation) 12.1 parts (surfactant; polyoxyethylene lauryl ether, HLB 13.6) ( 6) N-methylpyrrolidone 1.2 parts (7) n-butanol 1.2 parts (8) diethylene glycol monobutyl ether 3.6 parts

[Composition of Crosslinking Agent Solution (b)] (1) 25% of 6% aqueous solution of boric acid (crosslinking agent) (2) 20 parts of 10% aqueous solution of PAA-10C (cationic mordant; manufactured by Nitto Boseki Co., Ltd.) (3) Ammonium chloride (surface pH adjuster) 0.2 part (4) Emulgen 109P (10%, manufactured by Kao Corporation)) 2 parts (surfactant; polyoxyethylene lauryl ether, HLB 13.6) ( 5) 52.8 parts of ion-exchanged water

[0120]

[Table 1]

From Table 1, it can be seen that the ink jet recording sheets of the examples have excellent ink receiving performance (glossiness, ink absorbency, water resistance, bleeding over time, light resistance, image density).
, The adhesion between the colorant receiving layer and the support was improved, and the occurrence of a peeling phenomenon due to bending or the like during use was able to be prevented. Moreover, in the manufacturing process,
It was also possible to avoid the peeling phenomenon of the color material image receiving layer which may be caused by the impact received during the cutting process, and also to prevent the layer from peeling off from the support due to the cutting. That is, the occurrence of the yield was suppressed. The ink jet recording sheet of Example 3 was particularly excellent in glossiness and print density.

[0122]

According to the present invention, the adhesiveness between the support and the colorant receiving layer is high, the handleability and the processability are excellent, and even after printing, it is possible to store it for a long time in a high temperature and high humidity environment. In addition, it is possible to provide an ink jet recording sheet that can stably hold an image without causing bleeding over time. Further, according to the present invention, it is possible to form a high-resolution, high-density image with good ink absorption, in addition to being strong and having high surface gloss without occurrence of cracks and the like, Is good, and an ink jet recording sheet excellent in light resistance and water resistance of an image portion can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of an atmospheric pressure plasma processing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Atmospheric pressure plasma processing apparatus 12, 14 Electrode 12a, 14a Electrode member 12b, 14b Solid derivative 16 Support 18 Gas inlet 20 Gas outlet

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 2C056 FC06 2H086 BA01 BA15 BA33 BA35 BA37 BA41 BA45

Claims (8)

[Claims] 1. An ink jet recording sheet having a color material receiving layer containing inorganic pigment fine particles, a water-soluble resin, and a mordant on a surface of a support, wherein the surface of the support on which the color material receiving layer is coated is provided. A sheet for ink jet recording, wherein the sheet is subjected to an atmospheric pressure plasma treatment. 2. The color material receiving layer is formed by applying a first coating solution containing the inorganic pigment fine particles and the water-soluble resin to the surface of the support, and simultaneously with or simultaneously with the coating. A second coating liquid containing a crosslinking agent capable of crosslinking the water-soluble resin and the mordant is applied during the drying of the coating layer to be performed and before the coating layer exhibits a reduced drying rate, and cured. The ink-jet recording sheet according to claim 1, wherein the sheet is obtained by performing the following. 3. The ink jet recording sheet according to claim 2, wherein the crosslinking agent is a boron compound. 4. The ink jet recording sheet according to claim 1, wherein the inorganic pigment fine particles are silica fine particles having an average primary particle diameter of 20 nm or less. 5. The sheet according to claim 1, wherein the water-soluble resin is polyvinyl alcohol. 6. The mass ratio (i: p) of the inorganic pigment fine particles (i) to the water-soluble resin (p) is 1.5: 1 to 1
The inkjet recording sheet according to any one of claims 1 to 5, wherein the ratio is within a range of 0: 1. 7. The sheet according to claim 1, wherein the colorant receiving layer has a porosity of 40 to 80%. 8. The ink jet recording sheet according to claim 1, wherein the mordant is a basic polymer.