JP2002052809A - Sheet for ink jet recording - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet for ink jet recording which is excellent in the glossiness of a recording surface and causes no blur with time of an image even in the environment of high temperature and high humidity, which is free of cracking or the like and strong, has excellent ink absorbing properties and makes the formed image have high resistances to light and water. SOLUTION: The sheet for ink jet recording contains a polymer which has a unit shown by the formula (1) at least and which is nonsoluble in water and soluble in an organic solvent substantially. [In the formula (1), R denotes hydrogen or a methyl group. R1, R2 and R3 denote an alkyl, an aryl and an aralkyl (these may have been replaced by a hydroxyl or an ether) independently respectively and the total of the number of carbon atoms of R1, R2 and R3 is an integer of 15 or more. X denotes paired anions].

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,
The present invention relates to a recording sheet having excellent ink receiving performance and less bleeding over time.

[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 in hardware, is compact, and has high quietness. It has been widely used in home use. Also, with the recent increase in resolution of inkjet printers, it has become possible to obtain so-called photo-like high-quality recorded materials. And
With the development of hardware (devices), various recording sheets for inkjet recording have 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; Furthermore, in the application of photo glossy paper used to obtain so-called photo-like high-quality recorded materials, in addition to the above, glossiness, surface smoothness, photographic paper-like texture similar to silver halide photography, etc. are also required. Is done.

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 plastic film, are known. However, all of these proposed recording sheets have extremely low glossiness and are insufficient for use as 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. Hei 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 (PVA). There has been proposed an ink jet recording sheet provided with a recording layer made of. The above technique is simply intended to improve the coating strength of the recording layer having a low binder content, and is inferior in gloss, so that
It was insufficient for use of 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
879, 60-168651, 60-
JP-A-171143 discloses polyvinyl alcohol, polyvinyl pyrrolidone, gelatin or the like coated on a support such as paper or a plastic film. These recording sheets are also excellent in glossiness, but are inferior in ink quick-drying properties, and thus are insufficient for photo glossy paper applications.

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 colorant 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, the above-described ink absorbency is improved, color mixture bleeding 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, but it is necessary to reduce the amount of a binder for forming the layer so that voids can be formed.
When 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.

In addition, the ink jet recording sheet includes:
For the purpose of fixing the dye component in the ink, it is widely used to add a compound having an amino group or an ammonium salt, particularly a polymer compound having these. For example, JP-A-60-83882 and JP-A-64-7528
No. 1, JP-A-59-20696, etc., (co) polymers of diallylammonium salt derivatives;
Allylamine salt copolymers described in 1-61887 and 61-72581, JP-A-6-340
No. 163, No. 4-288283, No. 9-30
Nos. 0810, 8-318672, 10-
No. 272830, JP-A-63-115780, and the like. Examples of vinyl (meth) acrylates having an ammonium salt, (meth) acrylamide-based (co) polymers, vinylbenzylammonium salt (co) polymers, and the like. ) Polymers, modified polyvinyl alcohol (PVA) described in JP-A-10-44588 and the like, JP-A-6-23426
No. 8, No. 11-277888, etc., amine / epichlorohydrin polyadducts described in JP-A-10-119418.
Many compounds are used, such as dihalide / diamine polyadducts described in Japanese Unexamined Patent Application Publication No. 11-58934 and polyamidines described in Japanese Unexamined Patent Application Publication Nos. 11-58934 and 11-28860.
By using these compounds, dyes are fixed and bleeding is prevented.

However, since these compounds are basically water-soluble polymers, water-soluble dyes cannot be completely immobilized, and improvement of bleeding, particularly at high temperature and high humidity, is still insufficient. . In addition, if the ink is stored in a clear file immediately after printing, the water in the ink and the high-boiling solvents (glycerin, diethylene glycol derivatives, etc.) contained in the ink in a small amount remain,
Again, bleeding over time occurs.

On the other hand, as described in the ink jet recording sheets described in JP-A-57-36692, JP-A-10-180034, JP-A-11-20302, and JP-A-8-244336, the compounds described above are used. As described above, an ink jet recording sheet containing a base latex having an amino group or an ammonium salt but being insoluble in water is known. These inkjet recording sheets are:
The use of the hydrophobic latex improves water resistance. However, it is necessary to add a large amount of the above-mentioned hydrophobic latex to an inkjet recording sheet using such a hydrophobic latex in order to impart sufficient water resistance. As a result, problems such as deterioration of image light resistance and deterioration of miscibility with a pigment are caused. In addition, many of these are used to latex hydrophilic monomer units such as amino groups and ammonium salts,
A crosslinkable monomer (that is, a monomer having two or more polymerizable functional groups in a molecule) is used. Therefore, the water-soluble ink hardly penetrates into these particles, and the ink receptivity is not sufficient. Furthermore, since the particulate compound is added, when used in a receiving layer of a porous film, the porous film closes the voids and impairs the ink absorption.

[0014] Further, since the latex using such a crosslinkable monomer is insoluble in organic solvents and the like,
It is difficult to handle. Although some examples of latexes using no crosslinkable monomer are also known, specific compounds are not shown.

Furthermore, Japanese Patent Application Laid-Open No. 1-18887 discloses a recorded medium characterized by containing a monomer unit having a quaternary ammonium salt in an amount of 1% by mass or more and containing a copolymer substantially insoluble in water. Materials are shown. However, the copolymer in this case is mainly of an acrylic type, and there is no description about a quaternary ammonium salt-containing polymer having a specific structure. Further, there is no description that the bleeding over time is improved by the addition of these compounds.

As described above, while the colorant receiving layer is strong without cracks or the like, it has good ink absorbency, can form a high-resolution and high-density image, and has a high formed image. 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 can stably hold an image without causing a wobble has not yet been provided.

[0017]

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, an object of the present invention is to provide an ink jet recording sheet capable of holding an image stably without bleeding over time even when stored for a long time in a high temperature and high humidity environment after printing. In addition, the present invention is free from cracks and the like, is strong, has high surface gloss, has good ink absorption, can form a high-resolution, high-density image, and has good color developability. Another object of the present invention is to provide an inkjet recording sheet having excellent light resistance and water resistance in an image area.

[0018]

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 comprising a substantially water-insoluble and organic solvent-soluble polymer having at least a unit represented by the following formula (1).

[0020]

Embedded image [In the formula (1), R represents hydrogen or a methyl group. R ¹ ,
R ² and R ³ each independently represent alkyl, aryl, aralkyl, (which may be substituted with a hydroxyl group or ether), and the total number of carbon atoms of R ¹ , R ² and R ³ is 15
Is an integer greater than or equal to. X represents a counter anion. ]

<2> In an ink jet recording sheet having a color material receiving layer on a support, the color material receiving layer comprises inorganic pigment fine particles, a water-soluble resin, and at least a unit represented by the following formula (1). And a polymer that is substantially water-insoluble and organic solvent-soluble.

[0022]

Embedded image [In the formula (1), R represents hydrogen or a methyl group. R ¹ ,
R ² and R ³ each independently represent alkyl, aryl, aralkyl, (which may be substituted with a hydroxyl group or ether), and the total number of carbon atoms of R ¹ , R ² and R ³ is 15
Is an integer greater than or equal to. X represents a counter anion. ]

<3> The polymer according to <1> or <1>, wherein the polymer comprises only the unit represented by the formula (1).
2> is an ink jet recording sheet.

<4> The colorant receiving layer further comprises a crosslinking agent capable of crosslinking the water-soluble resin.
2> or <3>.

<5> The inkjet recording sheet according to <4>, wherein the crosslinking agent is a boron compound.

<6> The color material receiving layer is formed by applying a first coating liquid containing the inorganic pigment fine particles and the water-soluble resin on the support, and (1) simultaneously with the application, (2) And / or (3) at least one of during the drying of the coating layer formed by the application and before the coating layer exhibits a reduced-rate drying rate, and (3) after the coating layer is dried to form a coating film. The inkjet recording sheet according to any one of <2> to <5>, which is obtained by applying a second coating solution containing the polymer.

<7> The color material receiving layer is obtained by mixing the inorganic pigment fine particles and the polymer in advance, and then applying a third coating solution mixed with the water-soluble resin. <2> to <5> are inkjet recording sheets.

<8> The cross-linking agent is added to any of the first, second, and third coating liquids and applied, or the cross-linking is performed separately from the first, second, and third coating liquids. Characterized by being obtained by applying a coating solution containing an agent.
6> or <7>.

<9> The inkjet recording sheet according to any one of <2> to <8>, wherein the inorganic pigment fine particles are silica fine particles having an average primary particle diameter of 20 nm or less.

<10> The water-soluble resin is polyvinyl alcohol or a derivative thereof.
> To <9> are inkjet recording sheets.

<11> The coloring material receiving layer has a porosity of 5
It has a three-dimensional network structure of 0 to 80%, and has a content ratio of the inorganic pigment fine particles (i) to the water-soluble resin (p) (i:
(p / mass ratio) of 1.5: 1 to 10: 1.

[0032]

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

<< Inkjet Recording Sheet >> (Polymer Having Unit Represented by Formula (1)) The inkjet recording sheet of the present invention comprises at least the following formula (1)
And a substantially water-insoluble and organic solvent-soluble polymer (hereinafter, may be referred to as a “polymer of the present invention”).

[0034]

Embedded image [In the formula (1), R represents hydrogen or a methyl group. R ¹ ,
R ² and R ³ each independently represent alkyl, aryl, aralkyl, (which may be substituted with a hydroxyl group or ether), and the total number of carbon atoms of R ¹ , R ² and R ³ is 15
Is an integer greater than or equal to. X represents a counter anion. ]

It is important that the polymer according to the present invention is substantially water-insoluble and organic solvent-soluble. In the present invention, by using the polymer as a mordant, bleeding with time can be significantly prevented as compared with the case where a conventional water-soluble mordant is used. Therefore, even when the ink jet recording sheet is stored for a long time in a high temperature and high humidity environment, it is possible to stably hold an image. here,
"Substantially water-insoluble and organic solvent-soluble polymer"
The term "the polymer may be slightly hydrophilic as a whole, but basically means that it is insoluble in water," and it means that the polymer is not soluble in water by 0.1% by mass or more. Also,
“Organic solvent-soluble” means soluble in an organic solvent or the like used when applying the polymer according to the present invention, and examples of the organic solvent include methanol, ethanol, n-propanol, i-propanol, and methoxy. Examples include alcohols such as propanol, ketones such as acetone and methyl ethyl ketone, tetrahydrofuran, acetonitrile, ethyl acetate, and toluene.

The above-mentioned compounds can be obtained, for example, by polymerizing a quaternary ammonium salt compound obtained by reacting a halogenated methylstyrene with a tertiary amine compound in a medium such as an organic solvent according to a conventional method. .
Alternatively, a halogenated methylstyrene is polymerized in advance,
It can also be synthesized by reacting a tertiary amine compound with the obtained polymer. Specifically, as halogenated methylstyrenes, chloromethylstyrene (p
Form, m form, o form, and any mixture thereof), bromomethylstyrene (p form, m form, o form, and any mixture thereof), chloromethyl-α methylstyrene (p
Body, m-body, o-body, and any mixture thereof).

It is important that the total number of carbon atoms of the tertiary amine compound used in this case is an integer of 15 or more. Further, the total number of carbon atoms is preferably 18 or more. When the total number of carbon atoms is less than 15, the effect of improving temporal bleeding becomes insufficient. Specific examples of the tertiary amine compound include tripentylamine, trihexylamine, trioctylamine, triisooctylamine, triphenylamine, N-methyl-N-dioctylamine, triisodecylamine, dimethyloctadecylamine, N- (2-hydroxyethyl) -N-dioctylamine, N- (2-methoxyethyl) -N-dioctylamine, dibutylbenzylamine and the like can be mentioned.

The above halogenated methylstyrenes and the above 3
As the reactant of the secondary amine compound, tripentyl-p-
Vinylbenzylammonium chloride, tripentyl-m-vinylbenzylammonium chloride, trihexyl-p-vinylbenzylammonium chloride,
Trihexyl-m-vinylbenzylammonium chloride, trihexyl-p-vinylbenzylammonium bromide, trihexyl-m-vinylbenzylammonium bromide, trioctyl-p-vinylbenzylammonium chloride, trioctyl-m-vinylbenzylammonium chloride, triisooctyl-p
-Vinylbenzylammonium chloride, triisooctyl-m-vinylbenzylammonium chloride,
Units such as N-methyl-N-dioctyl-N- (p-vinylbenzyl) ammonium chloride and N-methyl-N-dioctyl-N- (m-vinylbenzyl) ammonium chloride are exemplified. These repeating units represented by the formula (1) may be used alone (as a homopolymer) or may be used as a copolymer of two or more kinds (as a copolymer).
May be used. Further, it may be used as a mixture of two or more polymers.

X is a counter anion and is not particularly limited, but specifically, halogens (Cl, Br,
I, F), sulfate ion, acetate ion or nitrate ion.

The polymer according to the present invention includes a polymer consisting of only the unit of the formula (1) (including a homopolymer and a copolymer consisting of two or more units). A homopolymer is particularly preferred, but is not particularly limited thereto, and may be a copolymer with a monomer copolymerizable with a unit other than the unit of the formula (1) as long as the performance as a recording sheet is not impaired. . Examples of such copolymerizable monomers include alkyl (meth) acrylates [eg, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and (meth) acrylic acid. Isopropyl, n-butyl (meth) acrylate,
Isobutyl (meth) acrylate, t (meth) acrylate
(Meth) acrylic acid C1 such as -butyl, hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate; -18 alkyl ester, etc.], cycloalkyl (meth) acrylate [cyclohexyl (meth) acrylate], aryl (meth) acrylate [phenyl methacrylate], aralkyl ester [(meth A) benzyl acrylate, etc.), substituted alkyl (meth) acrylates [eg, 2-hydroquinethyl (meth) acrylate], (meth) acrylamides [eg, (meth)
Acrylamide, dimethyl (meth) acrylamide, etc.], aromatic vinyls [styrene, vinyltoluene, α
-Methylstyrene etc.], vinyl esters [vinyl acetate, vinyl propionate, vinyl versatate etc.],
Examples include allyl 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]. These nonionic monomers can be used alone or in combination of two or more.

However, the type of these copolymerized monomers,
In selecting the amount to be used, it is important that the polymer be kept substantially insoluble in water. When a copolymer is used, the content of the repeating unit represented by the formula (1) in the copolymer is preferably 10 mol% or more, and 20 mol%.
More preferably, it is more preferably 30 mol% or more. If the amount is less than 10 mol%, the fixation of the dye is insufficient and the resolution and the effect of preventing bleeding over time become insufficient. The molecular weight of the polymer having the unit represented by the above formula (1) is preferably about 1,000 to 500,000 as a weight average molecular weight measured by gel permeation chromatography (GPC),
000 to 400,000 is more preferred. Molecular weight 10
If it is less than 00, the water resistance tends to be insufficient, and 500
If it is more than 000, the viscosity becomes high, and the handling aptitude becomes poor.

If necessary, a known polymer (a so-called mordant) or a low-molecular compound having a quaternary ammonium salt or a tertiary amine may be used as long as it does not deteriorate the performance as a recording sheet. More than one species may be used in combination. The mordants can be broadly classified into polymer mordants and non-polymer mordants. These compounds do not need to be particularly water-insoluble, and may be used in combination with a general (in many cases) water-soluble mordant. Preferred polymer mordants include polydiallyldimethylammonium chloride,
Polymethacryloyloxyethyl-β-hydroxyethyldimethylammonium chloride, polyethyleneimine, polyallylamine, polyallylamine hydrochloride, polyamide-polyamine resin, cationized starch, dicyandiamide formalin condensate, dimethyl-2-hydroxypropylammonium salt polymer, polyamidine And polyvinylamine. These compounds preferably have a molecular weight of about 1,000 to 500,000,
2000 to 400,000 is more preferred. Molecular weight 1
If it is less than 000, water resistance tends to be insufficient, and 50
If it is 0000 or more, the viscosity becomes high, and the handling aptitude becomes poor. On the other hand, as a non-polymeric mordant, a fourth mordant having a total number of carbon atoms of 12 or more, preferably 18 or more.
Compounds having a quaternary ammonium base can be mentioned.

[Coloring Material Receiving Layer] In the ink jet recording sheet of the present invention, the polymer according to the present invention can be used alone on a support, but the color further contains inorganic pigment fine particles and a water-soluble resin. It is also preferable to form and use a material receiving layer. Another embodiment of the ink jet recording sheet of the present invention has an inorganic pigment fine particle, a water-soluble resin, and at least a unit represented by the above formula (1) on a support.
A polymer that is substantially water-insoluble and organic solvent-soluble,
And a colorant receiving layer containing: In this case, the content of the polymer according to the present invention or the known mordant is 0.5 to the total solid content of the colorant receiving layer.
To 25.0% by mass is preferred, and 1.0 to 20.0% by mass.
Is more preferred. If the content is less than 0.5% by mass, sufficient water resistance and the effect of preventing bleeding over time cannot be obtained. On the other hand, when the content exceeds 25.0% by mass, the ink absorbency is deteriorated.

(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 even 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 thereof, 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 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) As the water-soluble resin,
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); and resins having an amide group or an amide bond, such as polyacrylamide (PAAM) and polyvinyl pyrrolidone (PVP). Further, having a carboxyl group as a dissociable group, polyacrylate,
Maleic acid resins, alginates and gelatins can be mentioned. 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 content of the coloring material 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 colorant receiving layer, may be a single material or a mixture of a plurality of materials.

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, the water-soluble resin is preferably polyvinyl alcohol (PVA).
9% PVA is more preferred, and PVA having a saponification degree of 70 to 90% is particularly preferred.

The above-mentioned PVA has a hydroxyl group in its structural unit, and 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 sheet passes through the transport system of the ink jet printer, stress may be applied to the recording sheet.
The colorant receiving layer needs to have sufficient film strength. Further, when the sheet is cut into a sheet shape, the color material receiving layer needs to have a sufficient film strength in order to prevent the color material receiving layer from cracking, peeling, and the like. In this case, the PB ratio is preferably 5: 1 or less, and is preferably 2: 1 or more from the viewpoint of ensuring 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.

(Crosslinking Agent) In the ink jet recording sheet of the present invention, it is also preferable to use a crosslinking agent capable of crosslinking the water-soluble resin in the colorant receiving layer.

The application of the crosslinking agent solution may be carried out simultaneously with the application of the coating solution for forming the porous colorant receiving layer (coating solution for the colorant receiving layer), or by applying the coating solution for the colorant receiving layer. 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 that occur while the coating layer dries. 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.
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, boron is preferred in that it causes a crosslinking reaction promptly.
Sand, boric acid and borate are preferred, especially water-soluble resins.
Can be used in combination with polyvinyl alcohol.
More preferred.

When gelatin is used as the water-soluble resin, the following compounds, which are known as hardeners for gelatin, can be used as crosslinking agents. 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; and 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 crosslinking agent solution is prepared by dissolving the crosslinking agent in water and / or an organic solvent. The concentration of the crosslinking agent in the crosslinking agent solution is 0.05% with respect to the mass of the crosslinking agent solution.
Is preferably from 10 to 10 mass%, particularly preferably from 0.1 to 7 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. As the organic solvent, any one can be used as long as it can dissolve the crosslinking agent.
Alcohols such as methanol, ethanol, isopropyl alcohol and glycerin; 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.

(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, various ultraviolet absorbers, antioxidants, singlet oxygen quencher and the like may be included. Examples of the ultraviolet absorber include cinnamic acid derivatives, benzophenone derivatives, and benzotriazolylphenol derivatives. For example,
α-cyano-phenyl cinnamate butyl, o-benzotriazolephenol, o-benzotriazole-p-chlorophenol, o-benzotriazole-2,4-di-
t-butylphenol, o-benzotriazole-2,
4-di-t-octylphenol and the like. 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 ultraviolet absorber, a salicylic acid-based ultraviolet absorber, a cyanoacrylate-based ultraviolet absorber, an oxalic acid anilide-based ultraviolet 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, for example, a coumarin fluorescent whitening agent. Specifically, Japanese Patent Publication Nos. 45-4699 and 54-53
No. 24, and the like.

Examples of the antioxidants 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 above light resistance improvers may be used alone or in combination of two or more. The lightfastness improver may be made water-soluble, dispersed, or emulsified, or may be contained in microcapsules. The amount of the light fastness improver to be added is preferably 0.01 to 10% by mass of the coating solution for the colorant receiving layer.

Further, for the purpose of enhancing 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.

[Support] As a material that can be used 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 a material include polyesters such as polyethylene terephthalate, cellulose esters such as nitrocellulose, cellulose acetate or cellulose acetate butyrate, and polysulfone, polyphenylene oxide, polyimide, polycarbonate, polyamide, and the like. 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 for paper and paperboard). Examples of high-gloss opaque supports include high-gloss paper such as art paper, coated paper, cast-coated paper, baryta paper used for silver halide photographic supports, and polyethylene terephthalate (PET). Polyesters, nitrocellulose, cellulose esters such as cellulose acetate and cellulose acetate butyrate, or plastic films such as polysulfone, polyphenylene oxide, polyimide, polycarbonate, or polyamide containing a white pigment or the like to make opaque high gloss ( (A surface calendering treatment may be performed.) A coating layer of a polyolefin containing or not containing a white pigment was provided on the surface of the film or the above-mentioned various papers, the above-mentioned transparent plastic film, or a plastic film containing a white pigment or the like. Branch Mention may be made of the body. Furthermore, a foamed polyester film containing a white pigment (eg, a foamed PET in which polyolefin fine particles are contained and voids are formed by stretching) can also be mentioned.

A polyolefin-coated paper generally used as a silver salt photographic support (eg, a paper support having a white pigment-containing polyolefin layer on its surface) or a special paper provided with a metal-deposited layer 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. Further, as the support, those subjected to a corona discharge treatment, a glow discharge treatment, a flame treatment, or an ultraviolet irradiation treatment in order to impart adhesion to the colorant receiving layer may be used.

[Method of Manufacturing Inkjet Recording Sheet] The method of manufacturing the inkjet recording sheet includes the following.
Examples include a method of applying a coating solution prepared in the form of an aqueous dispersion containing the polymer according to the present invention, an organic solvent solution, or a mixed solution of water and an organic solvent on a support, but are not limited thereto. Not something. However, it is particularly preferable to apply the polymer according to the present invention as a dissolved solution from the viewpoint of the glossiness of the obtained coating film.

(Organic solvent) Examples of the organic solvent that can be used for the above coating include alcohols such as methanol, ethanol, n-propanol, i-propanol and methoxypropanol; ketones such as acetone and methyl ethyl ketone; tetrahydrofuran and acetonitrile. , Ethyl acetate, toluene and the like.

(Method of Forming Coloring Material Receiving Layer) Next, another embodiment of the present invention, for ink jet recording, in which the coloring material receiving layer contains fine particles of inorganic pigment, a water-soluble resin and the polymer according to the present invention. The production of the sheet will be described. First, as a method for forming the colorant receiving layer, for example, an aqueous dispersion of inorganic pigment fine particles and a water-soluble resin (an organic solvent may be used in combination with water as appropriate. The solution according to the present invention is prepared during the drying of the coating layer formed by the coating, etc., and before the coating layer exhibits a reduced drying rate. A coating solution prepared in the form of an aqueous dispersion, an organic solvent solution, or a mixed solution of water and an organic solvent (hereinafter referred to as a “second coating solution”)
There is a case. ) Is given. Alternatively, a method in which the first coating liquid is prepared, applied, and dried to form a coating film, and then the second coating liquid is applied.

In the present invention, the first material for a colorant receiving layer containing at least inorganic pigment fine particles and a water-soluble resin.
Can be prepared, for example, as follows. 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
After dispersing for 20 minutes (preferably 10 to 30 minutes) under the condition of high-speed rotation (preferably 5000 to 20000 rpm), an aqueous polyvinyl alcohol solution (for example, PVA having a mass of about 1/3 of silica) is added. In addition, it can be prepared by dispersing 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 solution.

The method of applying the first coating solution is as follows: (1) a method of applying the solution on a support, (2) a method of spraying the first coating solution by a method such as spraying, and (3)
A method of immersing the support or the like in the first coating liquid may be used. The application of the first coating solution 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.

The above-mentioned “before the coated layer exhibits the reduced drying rate” usually refers to a few minutes immediately after the application of the first coating liquid. Shows the constant rate drying rate, which is a phenomenon in which the content of the solvent decreases in proportion to time. The time showing the constant rate drying rate is described in Chemical Engineering Handbook (pp. 707-712, Maruzen Co., Ltd.).
Published, October 25, 1980).

As described above, after the application of the first coating solution,
The coated layer is dried until it exhibits a lapse rate drying rate, which is generally performed at 50 to 180 ° C. for 0.5 to 10 minutes.
(For preferably 0.5 to 5 minutes). The drying time depends on the amount of application, but the above range is appropriate.

Before the coating layer exhibited the rate of drying, the liquid was prepared in the form of an aqueous dispersion containing the polymer according to the present invention, an organic solvent solution, or a mixed solution of water and an organic solvent. As a method of applying the coating liquid (second coating liquid), (1) a method of further applying the second coating liquid on the coating layer, and (2) spraying the second coating liquid by a method such as spraying. And (3) a method in which the support on which the coating layer is formed is immersed in the 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. In addition, two or more kinds of coating solutions may be applied in a multilayer coating simultaneously.

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 1 hour.
This is done by heating for 0 minutes, preferably
It is performed by heating at 40 to 100 ° C for 0.5 to 5 minutes. For example, when using borax or boric acid as a cross-linking agent contained in the cross-linking agent solution, it is preferable to heat at 60 to 100 ° C. for 5 to 20 minutes.

Further, after preliminarily mixing a substantially water-insoluble and organic solvent-soluble polymer having at least a unit represented by the above formula (1) (polymer according to the present invention) and inorganic pigment fine particles, Further, a coating liquid mixed with a water-soluble resin (which may further contain an aqueous dispersion or an organic solvent; hereinafter may be referred to as a "third coating liquid") can be applied. As a method for preparing the third coating liquid, the polymer according to the present invention is mixed and dispersed with inorganic pigment fine particles in a dissolvable solvent by a known method, and a water-soluble resin or water-soluble A method obtained by mixing a resin aqueous solution can be used. As a method of applying the third coating liquid, (1) a method of coating the third coating liquid on a support,
(2) a method of spraying the third coating liquid by a method such as spraying, and (3) a method of immersing the support in the liquid of the third coating liquid. Further, as the third coating liquid,
The dispersion obtained by mixing the polymer according to the present invention and the inorganic fine particles is further dispersed in water or an aqueous medium (which may have a suitable dispersant) and, if necessary, an organic solvent. The polymer according to the present invention and the inorganic pigment fine particles are redispersed in a coating solution obtained by mixing a water-soluble resin or a water-soluble resin aqueous solution with a coating solution obtained by removing a solvent, or a water-soluble resin aqueous solution. Then, a coating solution or the like obtained by removing the organic solvent as necessary can be used.

Further, a crosslinking agent may be added to any of the above-mentioned first, second and third coating solutions, and the crosslinking agent may be coated on a support or the like. The crosslinking agent may be added to two or more of the first, second, and third coating solutions. Alternatively, a coating solution containing a crosslinking agent may be prepared separately from the first, second, and third coating solutions, and applied at any stage of the coating process.

In each step of the above-mentioned coating, water, an organic solvent, or a mixed solvent thereof can be used as a solvent. Examples of the organic solvent that can be used for this coating include alcohols such as methanol, ethanol, n-propanol, i-propanol and methoxypropanol, ketones such as acetone and methyl ethyl ketone, tetrahydrofuran, acetonitrile, ethyl acetate, and toluene. Can be

After the color material receiving layer is formed on the support, the color material receiving layer is smoothened by calendering through a roll nip under heat and pressure using, for example, a super calendar or a gloss calendar. Nature, glossiness,
It is possible to improve transparency and coating film 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. The linear pressure between the rolls during the calendering process is preferably 50 to 400 kg / cm, and more preferably 100 to 200 kg / cm.

The layer thickness of the color material receiving layer needs to be determined in relation to the porosity in the layer, because in the case of ink jet recording, it is necessary to have an absorption capacity to absorb all the droplets. . For example, when the ink amount is 8 nL / mm ² and the porosity is 60%, a film having a layer thickness of about 15 μm or more is required. Considering this point, in the case of ink jet recording, the layer thickness of the colorant receiving layer is 10 to 5
0 μm is preferred.

The pore size of the colorant receiving layer is preferably from 0.005 to 0.030 μm in 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 guide, 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 above haze value is measured with a haze meter (H
GM-2DP: Suga Test Instruments Co., Ltd.).

On the support, for the purpose of enhancing the adhesiveness between the colorant receiving layer and the support and adjusting the electric resistance,
An undercoat layer may be provided. 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. When used in OHP or the like and the colorant receiving layer is provided on only one surface of the support, an antireflection film can be provided on the opposite surface or both surfaces for the purpose of enhancing light transmittance. .

Further, a boric acid or boron compound is coated on the surface of the support on the side where 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.

[0095]

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 “%” all represent “parts by mass” and “% by mass”.

[Synthesis Example 1] <Synthesis of trihexyl-vinylbenzylammonium chloride> 40.0 parts of chloromethylstyrene (mixture of p-form and m-form), 60.0 parts of trihexylamine, 0.6 parts of hydroquinone monomethyl ether Was dissolved in 130 parts of acetonitrile, and this solution was heated and stirred at 85 ° C. for 7 hours. Then, the reaction solution was washed with 110 parts of hexane,
The acetonitrile solution was concentrated to dryness. This was recrystallized from ethyl acetate to obtain 52.7 parts of colorless crystals of trihexyl-vinylbenzylammonium chloride.

<Synthesis of Poly (trihexyl-vinylbenzylammonium chloride)> 50.0 parts of trihexyl-vinylbenzylammonium chloride is dissolved in 45.0 parts of ethanol. This was heated to 60 ° C. under a nitrogen stream, and a solution of 0.19 parts of AIBN (2,2′-azobisisobutyronitrile) in 5.0 parts of ethanol was added.
The mixture was stirred while heating at 60 ° C. for 5 hours. A solution of 146 parts of ethanol was added to the reaction solution, and the solution was poured into 2,000 parts of water while stirring, and the resulting solid was filtered and dried to obtain poly (trihexyl-vinylbenzylammonium chloride) (polymer 1). 39.0 parts of a white solid were obtained.

[Synthesis Example 2] Poly (tripentyl-vinylbenzylammonium chloride) (polymer 2) was obtained in the same manner as in Synthesis Example 1 except that trihexylamine in Synthesis Example 1 was changed to tripentylamine. 5 parts were obtained.

Synthesis Example 3 Poly (triisooctyl-vinylbenzylammonium chloride) (Polymer 3) was prepared in the same manner as in Synthesis Example 1 except that trihexylamine in Synthesis Example 1 was changed to triisooctylamine. To 37.4
I got a copy.

[Synthesis Example 4] 32.0 parts of poly (triethyl-vinylbenzylammonium chloride) (polymer 4) was prepared in the same manner as in Synthesis Example 1 except that trihexylamine in Synthesis Example 1 was changed to triethylamine. Obtained.

[Synthesis Example 5] Poly (dimethylbenzyl-vinylbenzylammonium chloride) (polymer 5) was obtained in the same manner as in Synthesis Example 1 except that trihexylamine in Synthesis Example 1 was changed to dimethylbenzylamine. .5
I got a copy.

[Example 1]-Preparation of support-Wood pulp consisting of 100 parts of LBKP was subjected to Canadian Freeness 300 by a double disc refiner.
beaten to 0.5 ml, epoxidized behenamide 05 parts, anionic polyacrylamide 1.0 part, polyamide polyamine epichlorohydrin 0.1 part, cationic polyacrylamide 0.5 part, all added at absolute dry mass ratio to pulp, Base paper having a basis weight of 170 g / m ² was produced by a fourdrinier machine.

To adjust the surface size of the above atoms, a fluorescent enhancer (White) was added to a 4% aqueous solution of polyvinyl alcohol.
ex BB, manufactured by Sumitomo Chemical Co., Ltd.) was added in an amount of 0.04%, impregnated with the above atoms so that the absolute dry mass was 0.5 g / m ² , dried, and then calendered. Thus, a substrate adjusted to a density of 1.05 was obtained.

After the corona discharge treatment was performed on the wire surface (back surface) side of the obtained base paper, high-density polyethylene was coated to a thickness of 19 μm using a melt extruder, and a resin having a matte surface was formed. A layer was formed (hereinafter, the resin layer surface may be referred to as a “back surface”). After subjecting the resin layer on the back side to corona discharge treatment, aluminum oxide (alumina sol 100, manufactured by Nissan Chemical Industries, Ltd.) and silicon dioxide (Snowtex O,
(Nissan Chemical Industry Co., Ltd.) in water at a ratio (mass ratio) of 1: 2, and the mass after drying is 0.2 g / m ^2.
It applied so that it might become.

Also, after the corona discharge treatment was applied to the felt side (front side) of the base paper, the anatase type titanium dioxide 10
Mass%, trace amount of ultramarine blue, and 0.01% by mass of optical brightener
A low density polyethylene having an MFR (melt flow rate) of 3.8 containing (to polyethylene) was melt-extruded to a thickness of 29 μm using a melt extruder to form a thermoplastic resin layer having a glossy surface. It is formed on the base paper (hereinafter, this surface may be referred to as “front surface”).
This was used as a support.

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

<Composition of the coating material for the colorant receiving layer> (1) 9.9 parts of silica fine particles (fine particles of inorganic pigment) (average primary particle diameter: 7 nm; Aerosil 300, manufactured by Nippon Aerosil Co., Ltd.) (2) ion-exchanged water 73.1 parts (3) 9% aqueous solution of polyvinyl alcohol (water-soluble resin) 31.6 parts (PVA420, manufactured by Kuraray Co., Ltd., saponification degree 81.8%, polymerization degree 2000)

-Preparation of Ink-Jet Recording Sheet of the Present Invention- Next, the colorant-receiving layer coating solution obtained above was applied to the above-mentioned support using an extrusion die coater for 200 hours.
The coating was performed at a coating amount of ml / m ² (coating step) and dried at 80 ° C. (wind speed 3 to 8 m / sec) using a hot air dryer 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 (polymer and crosslinking agent-containing solution) having the following composition for 30 seconds to deposit 20 g / m ² on the coating layer (a step of applying the polymer and crosslinking agent-containing solution), Then, it was further dried at 80 ° C. for 10 minutes (drying step). As a result, a colorant 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 Polymer and Crosslinking Agent-Containing Solution> (1) 1.8 parts of boric acid (crosslinking agent) (2) 2.4 parts of 10% aqueous solution of surfactant (F144D, Dainippon Ink and Chemicals, Inc.) (3) Ethanol 103.5 parts (4) Poly (trihexyl-vinylbenzylammonium chloride) (Polymer 1 shown in Synthesis Example 1) 7.1 parts

(Evaluation Method) (1-1) Ink Absorption Rate Using an inkjet printer (PM-770C, manufactured by Seiko Epson Corporation), Y (yellow), M (magenta), C (Cyan), K
(Black), B (blue), G (green), and R (red) solid images are printed. 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.

(1-2) Generation of Cracks The presence or absence of cracks generated on the surface of the ink jet recording sheet and the size thereof were visually observed and evaluated according to the following criteria. [Criteria] AA: No crack was observed on the surface. BB: A crack having a length of 1 to 2 mm was observed. CC: Cracks having a length of 3 mm or more were observed.

(1-3) Water resistance Using the same printer as in the above (1-1), 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 (1-1), a grid-like linear pattern (line width of 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, and 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: Slight bleeding over time was recognized, but at a level that was not problematic in practical use. (Line width: 0.31 to 0.35 mm) CC: The bleeding with time was remarkably recognized, which was a level having a problem in practical use. (Line width: 0.35 or more)

Table 1 below shows the results of these evaluations.

[Examples 2 and 3, Comparative Examples 1 to 3]
In Example 1, an ink jet recording sheet was prepared and evaluated in the same manner as in Example 1, except that the polymer 1 shown in Synthesis Example 1 was changed to the polymer shown in Table 1. The results are shown in Table 1 below.

[0116]

[Table 1]

From Table 1, it was found that when the polymer according to the present invention was used as a mordant, generation of bleeding over time was not observed. Good results were also obtained with respect to the ink absorption rate, cracks on the recording sheet surface, and water resistance. On the other hand, when the water-soluble mordant was used, slight bleeding with time was observed. Further, when no mordant was used, the occurrence of bleeding with time was remarkably observed, and the result that the water resistance was low was obtained.

Example 4, Comparative Example 4 Preparation of Support A wood pulp composed of 80 parts of LBKP and 20 parts of NBKP was beaten to a Canadian freeness of 430 ml with a double disc refiner, and 10 parts of kaolin and 0.4 parts of cationic starch were used. Part, polyacrylamide 0.2
Parts and 0.075 parts of a neutral rosin sizing agent were added at an absolute dry mass ratio to the pulp, and a base paper having a basis weight of 80 g / m ² was produced by a fourdrinier paper machine. A 20% by mass ethanol solution of the polymer 1 shown in Synthesis Example 1 was applied to the substrate such that the coating amount after drying was 2 g / m ² to obtain a recording sheet. In addition, as Comparative Example 4, one using the substrate as it was without performing the above coating was used for evaluation.

(Evaluation Method) (2-1) Image Density A solid image of K (black) was printed on an ink jet recording sheet by an ink jet printer (PM-770C, manufactured by Seiko Epson Corporation) and left for 3 hours. The reflection density of the printed surface was measured with a Macbeth reflection densitometer.

(2-2) Water resistance Using the same printer as in the above (2-1), Y (yellow), M (magenta), C (cyan), K (black), B (Blue), G (green) and R (red) were printed solidly, left for 3 hours, immersed in water for 1 minute, visually observed the degree of the ink flowing out into water, and evaluated according to the following criteria. did. [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.

The results of the evaluation are shown in Table 2 below.

[0122]

[Table 2]

From Table 2, it can be seen that when the polymer according to the present invention was directly coated on the support, the image density was higher and the occurrence of bleeding with time was significantly reduced as compared with the case where no mordant was used. all right. Note that, in Examples 1 to 3, the case where the polymer of the present invention was contained in the colorant receiving layer containing the inorganic pigment fine particles and the water-soluble resin on the support, and in Example 4,
When compared with the case where the polymer according to the present invention was directly applied on the support, the occurrence of bleeding over time was able to be suppressed in the ink jet recording sheets in Examples 1 to 3.

[0124]

According to the present invention, it is possible to provide an ink jet recording sheet capable of stably holding an image without bleeding over time even when stored for a long time in a high temperature and high humidity environment after printing. Can be. 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.

Continued on the front page (72) Inventor Mizuki Yamamoto 200 Onakazato, Fujinomiya City, Shizuoka Prefecture Fuji Photo Film Co., Ltd. F-term (reference) 2H086 BA02 BA33 BA35 BA36 BA45 4J100 AB07P BA32P CA01 JA13

Claims (11)

[Claims] 1. An ink jet recording sheet comprising a substantially water-insoluble and organic solvent-soluble polymer having at least a unit represented by the following formula (1). Embedded image [In the formula (1), R represents hydrogen or a methyl group. R ¹ ,
R ² and R ³ each independently represent alkyl, aryl, aralkyl, (which may be substituted with a hydroxyl group or ether), and the total number of carbon atoms of R ¹ , R ² and R ³ is 15
Is an integer greater than or equal to. X represents a counter anion. ] 2. In an ink jet recording sheet having a color material receiving layer on a support, the color material receiving layer comprises inorganic pigment fine particles, a water-soluble resin and at least the following formula (1).
A substantially water-insoluble and organic solvent-soluble polymer having a unit represented by the formula: Embedded image [In the formula (1), R represents hydrogen or a methyl group. R ¹ ,
R ² and R ³ each independently represent alkyl, aryl, aralkyl, (which may be substituted with a hydroxyl group or ether), and the total number of carbon atoms of R ¹ , R ² and R ³ is 15
Is an integer greater than or equal to. X represents a counter anion. ] 3. The ink jet recording sheet according to claim 1, wherein the polymer comprises only the unit represented by the formula (1). 4. The colorant receiving layer according to claim 2, further comprising a crosslinking agent capable of crosslinking the water-soluble resin.
Or the inkjet recording sheet according to 3. 5. The sheet according to claim 4, wherein the crosslinking agent is a boron compound. 6. The color material receiving layer is provided with a first coating liquid containing the inorganic pigment fine particles and the water-soluble resin on the support, and (1) simultaneously with the application, (2) The drying of the coating layer formed by the application and before the coating layer exhibits a reduced drying rate, and (3) at least one of after drying the coating layer to form a coating film, The inkjet recording sheet according to any one of claims 2 to 5, wherein the sheet is obtained by applying a second coating liquid containing a polymer. 7. The color material receiving layer is obtained by mixing the inorganic pigment fine particles and the polymer in advance and then applying a third coating liquid mixed with the water-soluble resin. Item 6. An ink jet recording sheet according to any one of Items 2 to 5. 8. The color material receiving layer may be provided by adding the crosslinking agent to at least one of the first, second and third coating liquids, or may be provided with the first, second and third coating liquids. The inkjet recording sheet according to claim 6, wherein the inkjet recording sheet is obtained by applying a coating liquid containing the cross-linking agent separately from the coating liquid of 3. 9. The ink jet recording sheet according to claim 2, wherein the inorganic pigment fine particles are silica fine particles having an average primary particle diameter of 20 nm or less. 10. The water-soluble resin is polyvinyl alcohol or a derivative thereof.
10. The ink jet recording sheet according to any one of 9. 11. The color material receiving layer has a porosity of 50-8.
It has a three-dimensional network structure of 0%, and the content ratio (i: p / mass ratio) between the inorganic pigment fine particles (i) and the water-soluble resin (p) is 1.5: 1 to 10: 1. The inkjet recording sheet according to any one of claims 2 to 10, wherein