JP2003080837A - Ink-jet recording sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink-jet recording sheet which can form an image high in resolution and density, is excellent in light resistance, holds the image stably without generating bleeding with the passage of time even when stored for a long time under high-temperature, high-humidity environment, and is excellent in production aptitude. SOLUTION: In the ink-jet recording sheet having a coloring matter accepting layer on the surface of a support, the coloring matter accepting layer is coated with a dispersion of fine cationic inorganic particles which is greater than 4.5 in pH and contains at least fine particles of an inorganic pigment and an aggregation preventing agent. The aggregation preventing agent is preferably produced from a polymer having a unit expressed by formula (1).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording material suitable for ink jet recording using a liquid ink such as an aqueous ink or an oil ink, or a solid ink which is solid at room temperature and is melted and liquefied to be used for printing. More specifically, the present invention relates to an ink jet recording sheet which is excellent in ink receiving performance, has a high print density in the image area, and has little blurring or fading of the dye in the image area 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 devices suitable for each information system have been developed and put into practical use. Among these recording methods, the inkjet recording method is capable of recording on various recording materials, and is relatively inexpensive in hardware,
Due to its compactness and high quietness, it is widely used not only in offices but also in so-called home use. In addition, with the recent increase in resolution of inkjet printers, it has become possible to obtain so-called photograph-like high-quality recorded matter. With the development of hardware (device), various recording sheets for inkjet recording have been developed.

The properties required for the above-mentioned recording sheet are generally: (1) quick-drying property (high ink absorption speed), (2) proper and uniform ink dot diameter (bleeding). No), (3) good graininess, (4) high dot roundness, (5) high color density, (6) high saturation (no dullness) ), (7) The printed part has good light resistance and water resistance,
(8) No blurring or fading of the image even after long-term storage, (9) high whiteness of the recording sheet, (10)
The storage stability of the recording sheet is good, (11) the deformation and dimensional stability are good (curl is sufficiently small), and (12) the hard running property is good. Furthermore, in the application of photo glossy paper used for obtaining so-called photographic-like high-quality recorded matter, in addition to the above, gloss, surface smoothness, photographic paper-like texture similar to silver halide photography are also required. To be done.

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

Further, in Japanese Patent Laid-Open No. 4-223190,
Is 0.1 g / m of borax or boric acid. ²The above is applied
5-20g / m on base paper²Synthetic silica and polybi
A recording layer made of nyl alcohol (PVA) was provided.
Ink jet recording paper has been proposed. The above technology
Is simply the coating strength of the recording layer with a low binder content.
The purpose is to improve it, and it is inferior in terms of gloss.
Therefore, it has been insufficient as a use of photo glossy paper.

Further, recording materials using various water-soluble polymers for obtaining gloss have been proposed. For example, JP-A-58-89391, JP-A-58-134784, JP-A-58-134786, and JP-A-60-44386.
No. 60-132785, No. 60-145.
879, 60-168651, 60-
There is known one in which polyvinyl alcohol, polyvinylpyrrolidone, gelatin or the like described in Japanese Patent No. 171143 or the like is coated on a support such as paper or a plastic film. These recording sheets are also excellent in terms of glossiness, but inferior in terms of quick-drying ink, so that they are insufficient for use as photo glossy paper.

On the other hand, in JP-A-7-276789, JP-A-8-174992, JP-A-11-115308, JP-A-11-192777, etc., the required characteristics and manufacturing cost of the above-mentioned ink jet recording sheet are satisfied. An inkjet recording sheet is proposed. The above-mentioned JP-A-7-276789 proposes a recording sheet in which a coloring material receiving layer having a three-dimensional structure having a high porosity and formed of fine particles of an inorganic pigment and a water-soluble resin is provided on a support. Has been done. According to this configuration,
It is said that the above-mentioned ink absorbability is improved, color mixture blurring 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 since the binder amount for layer formation needs to be reduced so that voids can be formed, the coating layer is rapidly dried. There is a defect that cracks occur and the transparency and appearance of the colorant receiving layer are impaired.

In Japanese Patent Laid-Open No. 11-115308, a gas phase method silica having an average primary particle diameter of 10 nm or less has a pH of 8.
In the above alkaline atmosphere, polyvinyl alcohol (P
A coating solution obtained by blending with VA) and then dispersing is applied, and after the application, a coating solution containing a curing agent for PVA and having a pH of 8 or more is further coated in a dry state, and dried to obtain a coloring material receiving layer. A method of forming the is described. However, according to this method, the print density and sharpness of the image are low, and a sufficient gloss feeling cannot be obtained.

In Japanese Patent Laid-Open No. 10-181190, a coloring material receiving layer is prepared by finely pulverizing and dispersing an aggregate pigment in a liquid containing a cationic resin and applying a coating liquid containing the pigment having a particle diameter of 500 nm or less. However, the glossy feeling is insufficient.

Further, JP-A-12-212135 describes an ink jet recording sheet containing a vapor phase method silica and a cationic polymer having a constitutional unit of a polydiallylylamine derivative, which is also an image. Print density, freshness and glossiness are low. Further, Japanese Patent Application Laid-Open No. 12-211241 describes a coating liquid for inkjet recording paper, which uses an aqueous dispersion having a pH of 1.0 to 4.5 and containing vapor-phase process silica. It is low and cracks occur on the surface of the recording sheet.

In Japanese Patent Laid-Open No. 10-119423 or 10-217601, a colorant 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. Due to its constitution, each of the above-mentioned inkjet recording sheets has excellent ink absorbency, has high ink absorbability capable of forming a high resolution image, and exhibits high gloss. However, from the viewpoint of texture with glossiness, since a support having a resin coating such as polyethylene on both surfaces thereof is used as the support, the high boiling point solvent remains in the colorant receiving layer as it is, and after printing, When stored in a high-temperature and high-humidity environment for a long time, the solvent diffuses together with the dye in the colorant-receptive layer, and blurring of the image over time (hereinafter,
There is a problem that "time-dependent blurring" may occur.

Further, the ink jet recording sheet contains
It has been widely practiced to add a compound having an amino group or an ammonium salt, particularly a polymer compound having such a compound, for the purpose of fixing a dye component in ink, for example, JP-A-60-83882. 64-7528
(Co) polymers of diallylammonium salt derivatives described in JP-A No. 1 and 59-20696, etc.
Allylamine salt copolymers described in JP-A No. 1-61887 and JP-A No. 61-72581, and JP-A-6-340.
No. 163, No. 4-288283, No. 9-30
No. 0810, No. 8-318672, No. 10-
No. 272830, JP-A No. 63-115780, and other vinyl (co) polymers such as (meth) acrylates having an ammonium salt, (meth) acrylamide (co) polymers, and vinylbenzyl ammonium salt (co) polymers. ) Polymer, modified polyvinyl alcohol (PVA) described in JP-A-10-44588, JP-A-6-23426
No. 8, JP-A-11-277888 and the like, amine-epichlorohydrin polyaddition products, JP-A-10-119418.
Dihalide / diamine polyaddition products described in JP-A No. 11-58934, polyamidines described in JP-A Nos. 11-58860, and allylamine hydrochloride, allylamine, diallyldimethylammonium described in JP-A No. 12-71603, etc. Many compounds such as salts and polymers are used. The ink jet recording sheet described in the above publication uses these compounds to immobilize the dye and prevent bleeding.

However, the ink jet recording sheet having the coloring material receiving layer having such a high porosity has advantages such as ink absorbency and high gloss, and although the blurring with time is being improved, the printed image is printed. Immediately after that, when it is stored in a clear file or the like, or particularly when it is stored for a long time under a high humidity condition, there is a problem that blurring of an image still occurs.

Further, there is known an ink jet recording sheet using a polyallylamine derivative or a polyvinylamine derivative (hereinafter sometimes referred to as "polyamines") as an ink jet recording sheet. For example, JP-A-63-280681 discloses an ink jet recording sheet using polyamines substituted with hydroxyalkyl having 2 to 3 carbon atoms. However, these ink jet recording sheets are still insufficient in the effect of preventing bleeding over time.

Japanese Unexamined Patent Publication (Kokai) No. 8-267904 discloses an ink jet recording sheet containing polyamines substituted with an alkyl group having 1 to 6 carbon atoms, a benzyl group and an aryl group. However, in these cases, the quaternary ammonium salt is an essential component, and the introduction of these substituents (substituents having particularly high hydrophobicity) is not intended to improve blurring over time. Further, the polyamines are not formed by a polymer reaction.

In addition, polyallylamine is disclosed in, for example, JP-A-6-340163, JP-A-6-340164, JP-A-7-242015, JP-A-8-142496, JP-A-8-267904, and JP-A-8-282029. And disubstituted products of polyallylammonium and trisubstituted products of polyallyl ammonium. However, since these derivatives are generally synthesized by polymerization of di-substituted allylamine or tri-substituted allyl ammonium salt, which has low polymerizability, there is a problem that the production suitability is poor. Furthermore, the introduction of these substituents is not intended to improve blurring over time.

Further, as an example of an ink jet recording sheet containing amines having a substituent other than an alkyl group, an aryl group and an aralkyl group, JP-A-11-58634 and 11-20307 disclose polyvinyl. An example is shown in which the amine is replaced by COH, COMe. However, this is an example as a part of the polyamidine mordant, and the effect of preventing bleeding over time was still insufficient even if these groups were introduced.

It is also known to use a polyallylamine salt or a polyvinylamine salt itself in an ink jet recording sheet. In the case of a polyallylamine salt, a great number of examples in which the salt portion is an inorganic salt are halogens such as chloro, bromo and iodo are known (Japanese Patent Laid-Open Nos. 61-61887 and 61-61887). 5878
No. 8, JP 61-72581, etc.), and sulfonic acid (JP-A-6-340163, JP-A 6-34063).
(Japanese Patent No. 164, etc.) are also known. When the salt portion of the polyallylamine salt is an organic acid, HOS
_{O 3, MeOSO 3, EtOSO 3} ( JP-A-61-618
87 gazette, the same 61-58788 gazette, the same 61-72.
No. 581, etc.). However, these are not for the purpose of suppressing generation of bleeding over time, and the effect of preventing bleeding over time is insufficient.

Further, the salt portion has acetic acid, phosphoric acid, benzoic acid, p-toluenesulfonic acid (JP-A-61-2878).
8 and 61-72581) and the like are known. However, since these are basically homopolymers, they are not for the purpose of improving the occurrence of bleeding with time, and the effect of preventing bleeding with time is insufficient. Further, JP-A-6-340163, JP-A-6-340164,
No. 7-242055, No. 8-142496, No. 8-282092, No. 8-318672, etc. show examples of the salt moiety such as alkylcarboxylic acid and alkylsulfonic acid. . However, in these cases, a specific component such as a quaternary salt, acrylamide, or hydroxyethyl (meth) acrylate is essential as a copolymerization component, and is not intended to improve bleeding with time, and has an effect of preventing bleeding with time. Is insufficient.

In the case of a polyvinylamine salt, examples in which the salt portion is an anion (Japanese Patent Laid-Open Nos. 11-58934 and 8-39927, etc.) are known.
However, the example of the salt portion is not particularly described, and in this case, it is one of the coexisting components of the polyamidine-based compound and is not intended to improve bleeding over time, and the effect of preventing bleeding over time is insufficient. Is.

As described above, it is strong without cracks and has a high surface gloss, and also has good ink absorbability and color developability, so that it is possible to form an image with high resolution and high density. It is known that inkjet recording sheets are excellent in light resistance, water resistance, gas resistance, and even when stored in a high temperature and high humidity environment for a long time without causing bleeding or fading over time, and also excellent in manufacturing suitability. Not not.

[0022]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art and achieve the following objects. That is, the object of the present invention is to form a high-resolution and high-density image, excellent in light resistance, and after printing, even when stored for a long time in a high-temperature and high-humidity environment, it does not cause bleeding over time, and is stable. An object of the present invention is to provide an inkjet recording sheet that holds an image and is excellent in manufacturing suitability.

[0023]

As a result of intensive studies for solving these problems, the present inventor has found that these problems can be solved by using the following ink jet recording sheet. The present invention has been reached.

Means for solving the above problems are as follows. That is, <1> In an inkjet recording sheet having a coloring material receiving layer on the surface of a support, the coloring material receiving layer contains at least inorganic pigment fine particles and an agglomeration inhibitor, and has a pH of more than 4.5. An inkjet recording sheet characterized by being coated with an inorganic fine particle dispersion. <2> The inkjet recording sheet according to <1>, wherein the anti-agglomeration agent is made of a polymer having at least a unit represented by the following general formula (1).

[0025]

[Chemical 3] [In the general formula (1), X ⁻ represents a counter anion, and m represents 0 or 1. <3> The aggregation inhibitor is a polymer (a) having at least an ammonium salt unit represented by the following general formula (1) and a unit represented by the following general formula (2): The inkjet recording sheet according to <1> or <2> above.

[0026]

[Chemical 4] [In the formula, X ⁻ represents a counter anion, and m and n are 0 or 1
Represents <4> The polymer (a) is obtained by reacting a polymer (b) having a unit represented by the general formula (2) with an acid. <3> Is a sheet for inkjet recording. <5> The inkjet recording sheet according to <4>, wherein the polymer (b) comprises only the unit represented by the general formula (2) or a derivative thereof. <6> The inkjet recording sheet according to any one of <1> to <5>, wherein the color material receiving layer further contains a water-soluble resin. <7> The inkjet recording sheet according to <6>, wherein the color material receiving layer further contains a crosslinking agent capable of crosslinking the water-soluble resin. <8> The inkjet recording sheet according to <7>, wherein the crosslinking agent is a boron compound. <9> The above-mentioned <1>, wherein the coloring material receiving layer further contains an organic mordant capable of fixing an anionic dye.
The inkjet recording sheet according to any one of <> to <8>. <10> The inkjet recording sheet according to <9>, wherein the organic mordant is polyallylamine or a derivative thereof. <11> The inorganic pigment fine particles have an average primary particle diameter of 2
Silica fine particles of 0 nm or less, or an average pore radius of 1
The sheet for inkjet recording according to any one of <1> to <10>, which is pseudoboehmite having a thickness of 10 nm. <12> The inkjet recording sheet according to any one of <6> to <11>, wherein the water-soluble resin is polyvinyl alcohol or a derivative thereof. <13> The coloring material receiving layer has a three-dimensional network structure with a porosity of 50 to 80%, and the mass ratio (i: p) of the inorganic pigment fine particles (i) and the water-soluble resin (p) is 1.5: 1 to 1
<1> to <12>, which is 0: 1
The inkjet recording sheet according to any one of 1. <14> The coloring material receiving layer applies a first coating liquid containing the inorganic pigment fine particles, the water-soluble resin, and the aggregation inhibitor on the surface of the support, and (1) simultaneously with the coating,
(2) Either during the drying of the coating layer formed by the coating and before the coating layer shows a reduction rate drying, or (3) after drying the coating layer to form a coating film. The inkjet recording sheet according to any one of <1> to <13>, which is formed by applying a second coating liquid containing an organic mordant. <15> The coloring material receiving layer is provided by adding the crosslinking agent to at least one of the first coating liquid and the second coating liquid, or the first coating liquid and the second coating liquid. The inkjet recording sheet according to any one of <1> to <14>, which is obtained by applying a coating liquid containing the crosslinking agent.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION The ink jet recording sheet of the present invention is an ink jet recording sheet having a coloring material receiving layer on the surface of a support, wherein the coloring material receiving layer contains at least inorganic pigment fine particles and an anti-aggregation agent. Having a pH of 4.
It is characterized by being coated with a cationic inorganic fine particle dispersion liquid larger than 5. Hereinafter, the color material receiving layer will be described first.

<Colorant Receiving Layer> (Aggregation Inhibitor) In the present invention, the aggregation inhibitor is preferably composed of a polymer having at least a unit represented by the following general formula (1).

[0029]

[Chemical 5] [In the general formula (1), X ⁻ represents a counter anion, and m represents 0 or 1. ]

Alternatively, the agglomeration inhibitor is a polymer having an ammonium salt unit represented by the general formula (1) and a unit represented by the following general formula (2) (hereinafter referred to as polymer (a)). In some cases).

[0031]

[Chemical 6] [In general formulas (1) and (2), X- represents a counter anion,
m and n represent 0 or 1. ]

Anion component X in the above general formula (1)
^- As can be used any organic acid residue or inorganic acid residue. As the organic acid residue, carboxylic acids,
Examples thereof include sulfonic acids and thiocarboxylic acids, and examples thereof include R—COO ⁻ , R—OSO ₂ ⁻ , (RO) ₂ P (═O).
Examples thereof include those represented by general formulas such as O ⁻ . Specific examples of R include alkyl groups (for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, t-butyl group,
n-hexyl group, cyclohexyl group, 2-ethylhexyl group, n-decyl group, n-dodecyl group, octadecyl group and the like, which may have a substituent),
Aralkyl groups (eg benzyl group, phenylethyl group,
Vinylbenzyl group, 1-phenylvinyl group, hydroxyphenylmethyl group, etc., aryl group (for example, phenyl group, naphthyl group, tolyl group, chlorophenyl group, dichlorophenyl group, trichlorophenyl group, bromophenyl group, hydroxyphenyl group, methoxyphenyl Group, acetoxyphenyl group, cyanophenyl group, vinylphenyl group). Of these, carboxylic acids and sulfonic acids are preferable, and R is methyl group, ethyl group, n
-Propyl group and isopropyl group are particularly preferable. Examples of the inorganic acid residue include halides (Cl ⁻ , F ⁻ , Br ⁻ ,
I ⁻ ), NO ₃ ⁻ , HSO ₄ ⁻ , H ₂ PO ₄ ⁻ , ClO ₄ ⁻ , BF
₄ ^-, PF ₆ ^- and the like, halides, NO ₃ ^- is preferable.

The polymer (a) can also be obtained by polymerizing a monomer corresponding to the unit represented by the general formula (1) or the general formula (2). For example, the repeating unit represented by the general formula (2) is used. It can also be obtained by a neutralization reaction between a polymer having a unit (hereinafter sometimes referred to as polymer (b)) and an acid. Further, it can also be obtained by desalting a polymer having a repeating unit represented by the general formula (1) (hereinafter sometimes referred to as polymer (c)). In general, allyl-based monomers have insufficient polymerizability, and in the case of polyvinylamine, since there is no monomer corresponding to vinylamine, its precursor (eg, N-vinylformamide, N-vinylacetamide, etc.) is used. Since it is necessary to hydrolyze after the polymerization, in consideration of the production suitability and the degree of freedom of synthesis, the polymer (a) in the present invention is more neutralized by the above-mentioned polymer (b) and the acid than the polymerization of the monomer. Alternatively, it is preferably obtained by desalting the polymer (c).

When the polymer (a) is obtained by reacting a polymer having a repeating unit represented by the general formula (2) (hereinafter sometimes referred to as polymer (b)) with an acid, the acid As carboxylic acids (for example, acetic acid, propionic acid, butyric acid,
Isobutyric acid, valeric acid, isovaleric acid, sorbic acid, stearic acid, benzoic acid, cinnamic acid, etc.), sulfonic acid (eg, methanesulfonic acid, benzenesulfonic acid, toluenesulfonic acid, dodecylsulfonic acid, etc.), inorganic acid (For example, hydrochloric acid, nitric acid, phosphoric acid, sulfuric acid, etc.) and the like.

When the polymer (a) is obtained by the above neutralization reaction, a known method can be used for the neutralization reaction. Examples of the known reaction include a method in which the above-mentioned polymer (b) and an acid are mixed in a solvent, and heating and the like are carried out if necessary. The solvent used for the neutralization reaction is not particularly limited as long as it does not significantly inhibit the reaction, and water, methanol, ethanol, acetone, acetonitrile, tetrahydrofuran, dimethylsulfoxide, dimethylformamide, dimethylacetamide, or the like or a mixture thereof. A solvent system or the like can be used. Among them, water or an organic solvent miscible with water is preferable from the viewpoint of production suitability.

Polymer (b) having a repeating unit represented by the general formula (2) used as a raw material for these neutralization reactions.
Is, for example, a polymer substantially consisting of units represented by the general formula (2) (a content of the units represented by the general formula (2) is 90% or more, preferably 95% or more) Can be mentioned. Since a polymer substantially consisting of the repeating unit represented by the general formula (2) is easily available as polyallylamine or polyvinylamine, use of these compounds as a starting material is also suitable from the viewpoint of production suitability. preferable.

When the polymer (a) is obtained by the desalting reaction, a known method can be used for the desalting reaction. As the known reaction, for example, a method of mixing the polymer (c) with an alkaline solution and subjecting it to dialysis treatment, or a method of subjecting it to desalting treatment with a strongly basic ion exchange resin can be mentioned. . The solvent used for the neutralization reaction is not particularly limited as long as it does not significantly inhibit the reaction, and water, methanol, ethanol, acetone, acetonitrile, tetrahydrofuran, dimethylsulfoxide, dimethylformamide, dimethylacetamide, or the like or a mixture thereof. A solvent system or the like can be used. Among them, water or an organic solvent miscible with water is preferable from the viewpoint of production suitability.

In the polymer (a) according to the present invention, the content of the unit represented by the general formula (1) is particularly limited so long as the pH of the dispersion according to the present invention is higher than 4.5. Not limited. Substantially 10 to 100 mol% is preferable, 15 to 100 mol% is more preferable, and 20 to 10 mol%.
0 mol% is particularly preferred. The above content is 10 mol%
If it is less than the above value, aggregation of the inorganic fine particles may occur. The content of the unit represented by the general formula (2) in the polymer (a) is preferably 90 mol% or less, and 85 mol%
The following is more preferable, and 80 mol% or less is particularly preferable. If the content is more than 90 mol%, the inorganic fine particles may aggregate.

In addition to the units represented by the general formulas (1) and (2), the above-mentioned polymer (a) may be any other copolymerizable monomer as long as it does not impair the performance as an inorganic fine particle aggregation inhibitor. It may be a copolymer with. Examples of the unit copolymerizable with these units include (meth) acrylic acid alkyl esters [eg, (meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester, (meth) acrylic acid propyl, (meth) acrylic acid). Isopropyl acid, n-butyl (meth) acrylate, isobutyl (meth) acrylate,
(Meth) such as t-butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, and stearyl (meth) acrylate. Acrylic acid C1-18 alkyl ester etc.], (meth) acrylic acid cycloalkyl ester [(meth) acrylic acid cyclohexyl etc.], (meth) acrylic acid aryl ester [phenyl ((meth) acrylic acid etc.]], aralkyl ester [(meta ) Benzyl acrylate and the like], substituted (meth) acrylic acid alkyl ester [eg, 2-hydroxyethyl (meth) acrylate and the like], (meth)
Acryamides (eg (meth) acrylamide, dimethyl (meth) acrylamide, etc.), aromatic vinyls [styrene, vinyltoluene, α-methylstyrene, etc.], vinyl esters [vinyl acetate, vinyl propionate, vinyl versatate, etc.] ], Allyl esters [allyl acetate, etc.], halogen-containing monomers [vinylidene chloride, vinyl chloride, etc.], vinyl cyanide [(meth) acrylonitrile, etc.], olefins [ethylene, propylene, etc.], etc. Examples include a polymer. Further, in particular, a polymer having a unit represented by the formula (2) is not a polymer of vinylamine but usually N-vinylformamide,
Since it is often obtained by hydrolyzing a polymer such as N-vinylacetamide, these units may remain.

It is also possible to use a monomer having an ionic or basic unit. For example, diallyldimethylammonium chloride, methacryloyloxyethyl-β
-Hydroxyethyldimethylammonium chloride,
Vinylbenzyltrialkylammonium salt, (meth)
Acryloylethyltrialkylammonium salt, (meth) acryloylpropyltrialkylammonium salt, (meth) acrylamidoethyltrialkylammonium salt, (meth) acrylamidopropyltrialkylammonium salt, [trialkyl and triethyl as the trialkyl group shown in these , Tripropyl, triisopropyl, tributyl, trihexyl, dimethylbenzyl, etc.], dialkylaminoethyl (meth) acrylate, dialkylaminopropyl (meth)
Examples thereof include acrylate, dialkylaminoethyl (meth) acrylamide, dialkylaminopropyl (meth) acrylamide [as the dialkyl group shown therein, dimethyl, diethyl, dibutyl, methylbenzyl and the like] and the like.

These copolymerizable components may be used alone or in combination of two or more. When a copolymer is used, the content of the repeating unit represented by formula (1) and / or (2) in the copolymer is preferably 20 mol% or more, more preferably 30 mol% or more, and 50 mol% or more.
% Or more is particularly preferable. If it is less than 20 mol%, aggregation of the inorganic fine particles occurs. The weight average molecular weight of the polymer having a unit represented by the general formula (1) and / or (2) is preferably about 1,000 to 500,000, more preferably 2,000 to 400,000. If the molecular weight is less than 1000, the water resistance tends to be insufficient, and 5
If it is 00000 or more, the viscosity becomes high, the handling suitability becomes poor, and the dispersibility decreases due to the formation of crosslinks between the inorganic particles.

The ink jet recording sheet of the present invention comprises
Although the inorganic pigment fine particles and the polymer (a) are contained on the surface of the support, a colorant receiving layer containing a water-soluble resin may be further formed and used. Another preferred embodiment of the present invention is an inkjet recording sheet having a coloring material receiving layer containing, on a support, inorganic pigment fine particles, a water-soluble resin, and the polymer (a) of the present invention. To be Further, if necessary, an undercoat layer may be provided on the surface of the support, or a back layer may be provided on the back surface of the support on which the coloring material receiving layer is provided. In this case, the content of the polymer (a) in the present invention is preferably 0.5 to 25.0 mass% with respect to the total solid content of the colorant receiving layer, and 1.0 to 20.
0 mass% is more preferable. The above content is 0.5 to 2
Within the range of 5.0% by mass, the water resistance and the effect of preventing bleeding with time are further improved, and deterioration of ink absorbency can be prevented.

(Inorganic pigment fine particles) Examples of the inorganic pigment fine particles include silica fine particles, colloidal silica, titanium dioxide, barium sulfate, calcium silicate, zeolite,
Kaolinite, halloysite, mica, talc, calcium carbonate, magnesium carbonate, calcium sulfate, boehmite, pseudo-boehmite and the like can be mentioned. Among them, silica fine particles and pseudo-boehmite are particularly preferable.

Since the silica fine particles have a particularly large specific surface area, they have high ink absorption and retention efficiency, and also have a low refractive index. Therefore, if they are dispersed to an appropriate particle size, they are transparent to the coloring material receiving layer. Is provided, and high color density and good color developability are obtained. The fact that the colorant receiving layer is transparent is not only for applications requiring transparency such as OHP, but also for obtaining high color density and good colorability when applied to recording sheets such as photo glossy paper. Is important in.

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

The silica fine particles have silanol groups on the surface thereof, and particles are likely to adhere to each other due to hydrogen bonds due to the silanol groups. Therefore, when the average primary particle diameter is 10 nm or less, the void ratio is large. The structure can be formed. Thereby, the ink absorption characteristics can be effectively improved.

The silica fine particles are roughly classified into wet method particles and dry method particles according to the manufacturing method. In the above wet method, activated silica is generated by acid decomposition of silicate,
The mainstream method is to obtain water-containing silica by appropriately polymerizing this and coagulating and precipitating it. 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 and vaporized by an arc in an electric furnace, and this is oxidized by air. The main method is to obtain anhydrous silica by the (arc method).

The hydrous silica and anhydrous silica obtained by these methods show different properties because of the difference in the density of silanol groups on the surface, the presence or absence of pores, and the like. In particular, anhydrous silica (silicic acid anhydride) is preferable because it easily forms a three-dimensional structure having a high porosity. Although the reason for this is not clear, in the case of hydrous silica, the density of silanol groups on the surface of the fine particles is as high as 5 to 8 / nm ^2, and the silica fine particles are likely to densely aggregate (aggregate). 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 2-3 / nm ^2, it causes sparse soft flocculation. As a result, it is estimated 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 2-3 / nm.
It is preferable to use silica (fine silica particles) of ² .

Pseudo-boehmite is also preferable as the above-mentioned inorganic pigment fine particles. Pseudo-boehmite is boehmite (compositional formula A
10OOH) crystal colloidal aggregates, preferably containing a binder. As the pore characteristics, the average pore radius is preferably 1 to 10 nm, more preferably 3 to 10 nm. The pore volume is 0.5 to 1.0 ml /
It is preferably in the range of g. The coating amount of the pseudo-boehmite is preferably in the range of 5 to 30 g / m ² . If the coating amount is less than 5 g / m ² , the absorptivity of the ink may be lowered or the glossiness may be deteriorated due to the influence of the unevenness of the substrate, which is not preferable. Coating amount is 3
If it exceeds 0 g / m ² , not only is pseudoboehmite consumed unnecessarily, but the strength of the pseudoboehmite may be reduced, which is not preferable.

The composition of the pseudo-boehmite coating liquid preferably contains 5 to 50 parts by mass of a binder based on 100 parts by mass of the pseudo-boehmite solid content, and the total solid content concentration is 5 to 3 parts.
Those of 0 mass% can be preferably used. The solvent of the coating liquid is preferably an aqueous system from the viewpoint of handleability. As the binder, an organic binder composed of a high molecular compound such as starch or a modified product thereof, polyvinyl alcohol and a modified product thereof, SBR latex, NBR latex, carboxymethyl cellulose, hydroxymethyl cellulose, polyvinylpyrrolidone can be preferably used.

(Inorganic Fine Particle Dispersion) The inorganic fine particle dispersion contains the above-mentioned inorganic pigment fine particles and an anti-aggregation agent, and p
H is a dispersion liquid larger than 4.5, and the colorant receiving layer is formed by coating the dispersion liquid of the inorganic fine particles. When the pH of the inorganic fine particle dispersion liquid is 4.5 or less, not only the effect of suppressing aggregation of the inorganic fine particles in the aggregation inhibitor decreases but also the light resistance of the inkjet recording sheet decreases. The lower limit of pH of the inorganic fine particle dispersion is more preferably 4.6 and even more preferably 4.8.

(Water-Soluble Resin) As the water-soluble resin,
For example, a resin having a hydroxyl group as a hydrophilic structural unit, polyvinyl alcohol (PVA), cation-modified polyvinyl alcohol, anion-modified polyvinyl alcohol, silanol-modified polyvinyl alcohol, polyvinyl acetal, cellulose resin [methyl cellulose (MC), ethyl cellulose ( EC), hydroxyethyl cellulose (HEC), carboxymethyl cellulose (CMC), etc.], chitins, chitosans, starches; polyethylene oxide (PEO) and polypropylene oxide (PP) which are resins having an ether bond.
O), polyethylene glycol (PEG), polyvinyl ether (PVE); polyacrylamide (PAAM) which is a resin having an amide group or an amide bond, polyvinylpyrrolidone (PVP), and the like. Further, polyacrylic acid salts, maleic acid resins, alginates and gelatins having a carboxyl group as a dissociative group can be mentioned. Among the above, polyvinyl alcohols are particularly preferable.

If the content of the water-soluble resin is too low, the film strength may be lowered and cracks may easily occur during drying, and if the content is too high, the voids may be easily clogged with the resin. As a result, the porosity may decrease and the ink absorbency may decrease. Therefore, the content of the water-soluble resin is preferably 9 to 40% by mass, more preferably 16 to 33% by mass, based on the total mass of the solid content of the colorant receiving layer.

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 combined with the silica fine particles is important. When the above anhydrous silica is used, polyvinyl alcohol (PVA) is preferable as the water-soluble resin, and the saponification degree is 70 to 9 among them.
9% PVA is more preferable, and P with a saponification degree of 90% or more is used.
VA is particularly preferred.

The PVA has a hydroxyl group in its structural unit, and the hydroxyl group and the silanol group on the surface of the silica fine particles form a hydrogen bond to form a three-dimensional network structure in which the secondary particles of the silica fine particles are chain units. Make it easier to form. It is considered that the formation of the above-mentioned three-dimensional network structure makes it possible to form a coloring material receiving layer having a porous structure with a high porosity. In inkjet recording, the porous coloring material-receiving layer obtained as described above can rapidly absorb ink by a capillary phenomenon and form dots with good circularity without ink blurring.

-Content ratio of inorganic pigment fine particles to water-soluble resin-Content ratio of inorganic pigment fine particles (preferably silica fine particles or pseudo-boehmite; i) and water-soluble resin [PB ratio (i: p), The mass of the inorganic pigment fine particles with respect to 1 part by mass of the water-soluble resin] has a great influence on the film structure of the colorant receiving layer. That is, as the PB ratio increases, the porosity, pore volume, and surface area (per unit mass) increase. But P
If the B ratio becomes too large, the film strength will decrease, and cracks will tend to occur during drying, and if the PB ratio is too small, the voids will become more likely to be blocked by the resin, resulting in a decrease in the void ratio. As a result, the ink absorbability may decrease. Therefore, the PB ratio (i: p) is 1.
5: 1 to 10: 1 is preferred.

Since the recording sheet may be stressed when passing through the transport system of the ink jet printer, it is necessary that the coloring material receiving layer has sufficient film strength. Further, in the case of cutting into a sheet shape, it is necessary that the coloring material receiving layer has sufficient film strength in order to prevent cracking or peeling of the coloring material receiving layer. 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 absorbency in 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 have a PB ratio of 2: 1 to 5:
When the coating solution completely dispersed in an aqueous solution in 1 was coated on a support and the coating layer was dried, a three-dimensional network structure having secondary particles of silica fine particles as chain units was formed, and the average pore diameter was It is possible to easily form a translucent porous film having a thickness of 30 nm or less, a porosity of 50% to 80%, a pore specific volume of 0.5 ml / g or more and a specific surface area of 100 m ² / g or more.

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

The above-mentioned crosslinking agent solution is applied at the same time as the coating liquid for forming the porous color material receiving layer (coating liquid for the color material receiving layer) is applied, or the coating liquid for the color material receiving layer is applied. It is preferable to be carried out before the coating layer formed by coating exhibits a decreasing rate of drying. By this operation, it is possible to effectively prevent the generation of cracks that occur during the drying of the coating layer. That is, at the same time when the coating liquid is applied, or before the coating layer shows a decreasing rate of drying, the crosslinking agent solution penetrates into the coating layer and reacts rapidly 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 significantly improved.

As the cross-linking agent capable of cross-linking the above water-soluble resin, a suitable one may be appropriately selected in relation to the water-soluble resin used in the colorant receiving layer, but among them, the crosslinking reaction is rapid. From the above, a boron compound is preferable, and examples thereof include borax, boric acid, borate (eg, orthoborate, In
_{BO 3, ScBO 3, YBO 3} , LaBO 3, Mg 3 (B
O ₃ ) ₂ , Co ₃ (BO ₃ ) ₂ , diborate (eg Mg _{2
B 2 O 5, Co 2 B} 2 O 5), metaborate (e.g., Li
_{BO 2, Ca (BO 2)} 2, NaBO 2, KBO 2), tetraborates _{(eg, Na 2 B 4 O 7 ·} 10H 2 O), pentaborate (e.g., KB ₅ O ₈ · 4H _{2 O, Ca 2 B 6 O 11} · 7H 2
O, CsB ₅ O ₅ ), glyoxal, melamine formaldehyde (for example, methylol melamine, alkylated methylol melamine), methylol urea, resole resin, polyisocyanate, epoxy resin and the like. Among them, borax, boric acid, and borate are preferable because they cause a crosslinking reaction quickly, and it is more preferable to use them in combination with polyvinyl alcohol as a water-soluble resin.

When gelatin is used as the water-soluble resin, the following compounds known as a hardening agent for gelatin 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; divinyl sulfonic acid, 1,3-vinylsulfonyl-2-propanol, N, N'-ethylenebis (vinylsulfonyl acetate) Cetamide), active vinyl compounds such as 1,3,5-triacryloyl-hexahydro-S-triazine; N-methylol compounds such as dimethylolurea and methyloldimethylhydantoin;

Isocyanate compounds such as 1,6-hexamethylene diisocyanate; US Pat. No. 301
Nos. 7280 and 2983611; 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 mucophenoxycyclo acid; dioxane compounds such as 2,3-dihydroxydioxane; chromium alum, potassium alum, zirconium sulfate, Chromium acetate and the like. The cross-linking agents 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 0.
05-10 mass% is preferable and 0.1-7 mass% is especially preferable. Water is generally used as the solvent constituting the crosslinking agent solution, and may be an aqueous mixed solvent containing an organic solvent miscible with the water. Any organic solvent can be used as long as it can dissolve the crosslinking agent, and examples thereof include alcohols such as methanol, ethanol, isopropyl alcohol, and glycerin; ketones such as acetone and methyl ethyl ketone; methyl acetate, ethyl acetate, and the like. And the like; aromatic solvents such as toluene; ethers such as tetrahydrofuran; and halogenated carbon solvents such as dichloromethane.

(Organic mordant) In the present invention, in order to further improve the water resistance and bleeding resistance of the formed image,
It is preferable that the colorant receiving layer contains an organic mordant (hereinafter, may be simply referred to as “mordant”). As the mordant, a cationic polymer (cationic mordant)
It is preferable that the presence of the mordant in the colorant-receptive layer interacts with a liquid ink having an anionic dye as a colorant to stabilize the colorant and improve water resistance and blurring over time. it can.

As the 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. As the polymer mordant, first to third
A homopolymer of a monomer (mordant monomer) having a primary amino group and a salt thereof or a quaternary ammonium salt group, or a copolymerization weight of the mordant monomer and another monomer (hereinafter, referred to as "non-mordant polymer"). Those obtained as a polymer or a condensation polymer are preferable. Further, these polymer mordants can be used in the form of either a water-soluble polymer or water-dispersible latex particles.

Examples of the above-mentioned monomer (mordanting monomer) include trimethyl-p-vinylbenzylammonium chloride, trimethyl-m-vinylbenzylammonium chloride, triethyl-p-vinylbenzylammonium chloride, triethyl-m-vinylbenzylammonium chloride. Chloride, N, N-dimethyl-N-ethyl-N-p-vinylbenzylammonium chloride,
N, N-diethyl-N-methyl-N-p-vinylbenzylammonium chloride, N, N-dimethyl-Nn
-Propyl-N-p-vinylbenzyl ammonium chloride, N, N-dimethyl-Nn-octyl-N-p
-Vinylbenzylammonium chloride, N, N-dimethyl-N-benzyl-Np-vinylbenzylammonium chloride, N, N-diethyl-N-benzyl-
N-p-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
-Vinylbenzyl ammonium 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, Methyl chloride of N-diethylaminopropyl (meth) acrylamide,
Examples thereof include ethyl chloride, methyl bromide, ethyl bromide, quaternary compounds of methyl iodide or ethyl iodide, and sulfonates, alkylsulfonates, acetates or alkylcarboxylates of which anions are substituted.

Specifically, for example, monomethyldiallylammonium chloride, trimethyl-2- (methacryloyloxy) ethylammonium chloride, triethyl-2- (methacryloyloxy) ethylammonium chloride, trimethyl-2- (acryloyloxy) ethylammonium chloride. , Triethyl-2-
(Acryloyloxy) ethylammonium chloride, trimethyl-3- (methacryloyloxy) propylammonium chloride, triethyl-3- (methacryloyloxy) propylammonium chloride, trimethyl-2- (methacryloylamino) ethylammonium chloride, triethyl-2- (methacryloyl) Amino) ethylammonium chloride, trimethyl-
2- (acryloylamino) ethylammonium chloride, triethyl-2- (acryloylamino) ethylammonium chloride, trimethyl-3- (methacryloylamino) propylammonium chloride, triethyl-3- (methacryloylamino) propylammonium chloride, trimethyl-3- (Acryloylamino) propyl ammonium 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 etc. can be mentioned. In addition, examples of copolymerizable monomers include N-vinylimidazole and N-vinyl-2-methylimidazole.

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

The above-mentioned (meth) acrylic acid alkyl ester has a carbon number of 1 to 18 at the alkyl moiety (meth).
Acrylic acid alkyl esters are preferable, 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 preferable. The non-mordant monomers can be used alone or in combination of two or more.

Further, as a polymer mordant, polydiallyldimethylammonium chloride, polymethacryloyloxyethyl-β-hydroxyethyldimethylammonium chloride, polyethylenimine, polyallylamine and its modified products, polyallylamine hydrochloride, polyamide-polyamine resin, cation Preferred examples include modified starch, dicyandiamide formalin condensate, dimethyl-2-hydroxypropylammonium salt polymer, polyamidine, and polyvinylamine.
Polyallylamine and its modified products are particularly preferred.

The modified polyallylamine is obtained by adding acrylonitrile, chloromethylstyrene, TEMPO, epoxyhexane, sorbic acid, etc. to polyallylamine in an amount of 2-5.
0 mol% added, preferably 5 to 10 mol% of acrylonitrile and chloromethylstyrene, particularly 5 to 10 mol% of polyallylamine.
Acrylonitrile adducts are preferable from the viewpoint of exerting the effect of preventing ozone fading.

The mordant preferably has a weight average molecular weight of 5,000 to 30,000. When the molecular weight is in the range of 5,000 to 300,000, water resistance and bleeding resistance over time can be improved.

The content of the organic mordant is preferably 0.5 to 25% by mass, and more preferably 1 to 20% by mass based on the total mass of the solid content of the colorant receiving layer.

(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 kinds of ultraviolet absorbers, antioxidants, and fading inhibitors such as singlet oxygen quencher may be contained. Examples of the ultraviolet absorber include cinnamic acid derivatives, benzophenone derivatives, benzotriazolylphenol derivatives and the like. 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 2-position or 6-position is substituted with a branched alkyl group is preferable.

Further, benzotriazole type ultraviolet absorbers, salicylic acid type ultraviolet absorbers, cyanoacrylate type ultraviolet absorbers, oxalic acid anilide type ultraviolet absorbers and the like can also be used. For example, JP-A-47-1053
No. 7, gazette 58-111942 gazette, gazette 58-21.
No. 2844, No. 59-19945, No. 59-
46646, 59-109055, and 6
No. 3-53544, Japanese Patent Publication No. 36-10466, No. 42-26187, No. 48-30492, No. 48-31255, No. 48-41572.
JP-A-48-54965 and JP-A-50-1072.
No. 6, gazettes, US Pat. Nos. 2,719,086, 3,707,375, 3,754,919, 4,220,711, etc. There is.

A fluorescent brightening agent can also be used as an ultraviolet absorber, and examples thereof include a coumarin-based fluorescent brightening agent. Specifically, JP-B-45-4699 and 54-53.
No. 24, etc.

Examples of the above-mentioned antioxidant include European Patent Nos. 223739, 309401, 309402, 310551, and 31.
No. 0552, No. 459416, German Published Patent No. 3435443, and Japanese Patent Laid-Open No. 54-48535.
No. 60-107384 and No. 60-107.
No. 383, No. 60-125470, No. 60-
No. 125471, No. 60-125472, No. 60-287485, No. 60-287486, No. 60-287487, and No. 60-28748.
8 gazette, the same 61-160287 gazette, the same 61-18.
5483, 61-211079 and 62.
No. 146678, No. 62-146680,
62-146679, 62-282885, 62-262047, 63-0511.
74, 63-89877, 63-88.
No. 380, No. 66-88381, No. 63-1.
No. 13536,

63-163351 and 63-2.
No. 03372, No. 63-224989, No. 6
No. 3-251282, No. 63-267594, No. 63-182484, Japanese Patent Laid-Open No. 1-2392.
82, JP-A-2-262654, and 2-7.
No. 1262, No. 3-121449, and No. 4-2.
No. 91685, No. 4-291684, No. 5-
No. 61166, No. 5-119449, No. 5-
No. 188687, No. 5-188686, No. 5
-110490 gazette, the same 5-1108437 gazette,
No. 5-170361, Japanese Patent Publication No. 48-43295, No. 48-33212, and U.S. Pat. No. 4,814.
No. 262, No. 4980275, etc. are mentioned.

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 -Ethylhexane, 2
-Methyl-4-methoxy-diphenylamine, 1-methyl-2-phenylindole and the like can be mentioned.

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

Further, for the purpose of improving the dispersibility of the fine particles of the inorganic pigment, various inorganic salts and a pH adjusting agent such as acid or alkali may be contained. Further, 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 frictional electrification and peeling electrification on the surface. It is preferable to include various matting agents for the purpose of reducing the frictional properties of the surface.

As the matting agent, a grain system of 3 μm to 30 is used.
A matting agent having a particle size of 10 μm is preferable, and a particle size of 10 μm to 30 μm is more preferable. Conventionally known matting agents can be used. Matting agents are well known in the photographic art and can be defined as discrete solid particles of an inorganic or organic material dispersible in a hydrophilic organic colloid binder. Examples of the inorganic matting agent include oxides (for example, silicon dioxide, titanium oxide, magnesium oxide, aluminum oxide, etc.), alkaline earth metal salts (for example, sulfates and carbonates, specifically, barium sulfate and carbonate). Examples thereof include calcium, magnesium sulfate, and calcium carbonate), silver halide grains that do not form an image (such as silver chloride and silver bromide, and a small amount of iodine atoms may be added as a halogen component) and glass.

In addition to the above-mentioned inorganic matting agents, for example, West German Patent No. 2,529,321 and British Patent No. 760,7.
No. 75, No. 1,260,772, US Pat. No. 1,201,905, No. 2,192,24.
1, No. 3,053,662, No. 3,0
62,649, 3,257,206, 3,322,555, 3,353,9
No. 58, No. 3,370,951 and No. 3,
411,907, 3,437,484, 3,523,022, 3,615,5
No. 54, No. 3,635,714, No. 3,
It is also possible to use the inorganic matting agents described in the specifications of No. 769,020, No. 4,021,245, No. 4,029,504 and the like.

The matting agent may be an organic matting agent, and examples of the organic matting agent include starch, cellulose ester (eg, cellulose acetate propionate), cellulose ether (eg, ethyl cellulose), synthetic resin and the like. Is mentioned. As the synthetic resin,
It is possible to use synthetic polymers that are insoluble or sparingly soluble in water, such as alkyl (meth) acrylate, alkoxyalkyl (meth) acrylate, glycysilyl (meth).
Acrylate, (meth) acrylamide, vinyl ester (eg vinyl acetate), acrylonitrile, olefin (eg ethylene), styrene, benzoguanamine / formaldehyde condensate, etc., alone or in combination,
Alternatively, it is possible to use a polymer having a monomer component of a combination of these with acrylic acid, methacrylic acid, α, β-unsaturated dicarboxylic acid, hydroxyalkyl (meth) acrylate, sulfoalkyl (meth) acrylate, styrenesulfonic acid, or the like. it can.

Further, as the organic matting agent, epoxy resin, nylon, polycarbonate, phenol resin,
Polyvinylcarbazole, polyvinylidene chloride, etc. can also be used. Besides this, British Patent No. 1,055
No. 713, U.S. Pat. No. 1,939,213, No. 2,221,873, No. 2,268,6.
No. 62, No. 2,322,037, No. 2,
376,005, 2,391,181, 2,701,245, 2,992,1
No. 01, No. 3,079,257, No. 3,
262,782, 3,443,946, 3,516,832, 3,539,3
No. 44, No. 3,591,379, No. 3,
754,924, 3,767,448, JP-A-49-106821, 57-148.
The organic matting agents described in JP-A-35-35 can be used.

As the organic matting agent, polystyrene beads (manufactured by Moritex), nylon beads (manufactured by Moritex), AS resin beads (manufactured by Moritex),
Epoxy resin beads (manufactured by Moritex), polycarbonate resin (manufactured by Moritex) and the like can be preferably used.

As the matting agent, an alkali-soluble matting agent can also be preferably used. Examples of the alkali-soluble matting agent include JP-A Nos. 53-7231 and 58-58.
Alkali-soluble matting agents such as alkyl methacrylate / methacrylic acid copolymers described in JP-A-66937 and JP-A-60-8894, and alkali-soluble matting agents having an anionic group described in JP-A-58-166341. Polymers can also be used.

Two or more of the above-mentioned matting agents may be used in combination, and examples of the combination of matting agents include JP-A-58-14.
No. 5,935, a combination of two or more kinds of fine particle powders having different Mohs' hardness, a combination of two or more kinds of spherical matting agents having different average particle sizes as described in JP-A-59-149356, and a colorant receiving layer. A combination of an amorphous matting agent such as silica and a spherical matting agent such as polymethylmethacrylate in the back layer may be used.

The coloring material-receptive layer and other layers in the present invention include coating aids, antistatic agents, slipperiness improvement, emulsion dispersion, adhesion prevention and photographic property improvement (for example, development acceleration, contrast enhancement,
Various surfactants may be included for various purposes such as sensitization). Examples of the surfactant include saponins (steroidal), alkylene oxide derivatives (eg, polyethylene glycol, polyethylene glycol / polypropylene glycol condensates, polyethylene glycol alkyl ethers or polyethylene glycol alkyl aryl ethers, polyethylene glycol esters, polyethylene). Glycol sorbitan esters, polyalkylene glycol alkylamines or amides, polyethylene oxide adducts of silicone),
Nonionic surfactants such as glycidol derivatives (eg, alkenyl succinic acid polyglyceride, alkylphenol polyglyceride), fatty acid esters of polyhydric alcohols, etc., alkyl carboxylates, alkyl sulfonates, alkylbenzene sulfonates Salts, alkylnaphthalene sulfonates, alkyl sulfates, alkyl phosphates, N-acyl-N-alkyl taurates, sulfosuccinates, esphoalkyl polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkyl eicos Carboxy group, sulfo group, such as sun acid esters,
An anionic surfactant containing an acidic group such as a phospho group, a sulfuric acid ester group, a phosphoric acid ester group;

Amphoteric surfactants such as amino acids, aminoalkyl sulfonic acids, aminoalkyl sulfates or phosphoric acid esters, alkylbetaines, amine oxides; alkylamine salts, aliphatic or aromatic quaternary ammonium salts, pyridinium , Cationic surfactants such as heterocyclic quaternary ammonium salts such as imidazolium and phosphonium or sulfonium salts containing an aliphatic or heterocyclic ring can be used.

A slip agent may be added to the color material receiving layer. Examples of the slip agent include higher alkyl sodium sulfate, higher fatty acid higher alcohol ester, carbowax, higher alkyl phosphate ester, and silicon compound. Especially US Pat. No. 2,882,15
No. 7, No. 3,121,060, No. 3,850,640, JP-A-51-14162.
The compounds described in JP-A-3, etc. are particularly effective when used alone or in combination of two or more kinds.

Also, French Patent No. 2,180,465, British Patent No. 955,061 and 1,1,
43,118, 1,270,578, 1,320,564, 1,320,7.
57, JP-A-49-5017 and 51-
141623, 54-159221, 56-81841, and Research Disclosure 1396.
9, US Pat. Nos. 1,263,722 and 2,
588,765, 2,739,891, 3,018,178, 3,042,5
No. 22, No. 3,080,317, No. 3,
082,087, 3,121,060, 3,222,178, 3,295,9
79, 3,489,567, 3,
516, 832, 3,658, 573, 3,679, 411, 3,870, 5
No. 21, etc. can be used. The appropriate amount of the above-mentioned sliding agent applied is about 5 to 200 mg / m ² .

Each layer of the ink jet recording sheet of the present invention may contain silica, especially colloidal silica, for the purpose of improving adhesion resistance, film strength, curl balance and the like.

<< Method for Producing Inkjet Recording Sheet >> Next, a method for forming the colorant receiving layer will be described. The colorant receiving layer in the present invention comprises a dispersion containing the vapor-phase process silica and the polymer (a) according to the present invention, the polyvinyl alcohol, a nonionic or amphoteric surfactant, and the high-boiling organic solvent. A first coating solution (coating solution for a colorant receiving layer) obtained by adding a solution having a pH of 7 or less is applied, and (1) simultaneously with the application, (2) a coating layer formed by the application. In the middle of drying, before the coating layer shows a rate of decrease in drying, (3) after drying the coating layer to form a coating film, the organic mordant is added to the coating layer. It has a porous structure formed by applying a second coating liquid containing the coating liquid and curing and drying the coating layer. The second coating liquid preferably contains the cross-linking agent and the nonionic surfactant, and is adjusted to have a pH of 8.5 or higher. ,

As described above, in the present invention, the water resistance of the colorant receiving layer can be improved by simultaneously applying the mordant together with the crosslinking agent. That is, when the mordant is added to the coating liquid for the colorant receiving layer, the mordant may be aggregated in the coexistence with the gas phase method silica having an anionic charge on the surface because the mordant is cationic. If a method of independently preparing a second coating liquid containing a pigment and a coating liquid for a colorant receiving layer and individually coating them is used, it is not necessary to consider the aggregation of the inorganic pigment fine particles, and the selection range of the mordant can be reduced. Spreads.

In the present invention, the first coating liquid (coloring material) containing vapor grown silica, the polymer (a) according to the present invention, PVA, a nonionic or amphoteric surfactant, and a high boiling organic solvent. The receiving layer coating liquid) can be prepared, for example, as follows. That is, after vapor phase silica is added to water, the polymer (a) according to the present invention is further added and dispersed by a high pressure homogenizer, a sand mill or the like, and then an aqueous polyvinyl alcohol solution (for example, 1 of vapor phase silica is used). It can be prepared by adding (to obtain a PVA having a mass of about / 3), further adding a nonionic or amphoteric surfactant and a high boiling point organic solvent, and stirring. The obtained coating liquid is a uniform sol, and a porous coloring material-receiving layer having a three-dimensional network structure can be formed by coating and forming this on a support by the coating method described below.

In the present invention, the pH of the first coating liquid is
It is preferably 4.5 to 7, more preferably 4.5 to 6.5, and further preferably 4.5 to 6.0. When the pH of the first coating liquid is higher than 7,
The image print density, sharpness, and glossiness may decrease. The pH of the first coating liquid can be adjusted to 7 or less by appropriately selecting the type and addition amount of the cationic resin. Further, it may be adjusted by adding an inorganic acid or alkali. If necessary, a pH adjusting agent, an antistatic agent, or the like can be added to the first coating liquid (coating liquid for the color material receiving layer).

The coating of the first coating liquid (coating liquid for the color material receiving layer) is carried out by known methods such as extrusion die coater, air doctor coater, bread coater, rod coater, knife coater, squeeze coater, reverse roll coater and bar coater. It can be performed by the coating method.

After applying the first coating liquid, the second coating liquid is applied to the coating layer. May be given before it becomes. That is, after applying the first coating liquid,
It is preferably produced by introducing a crosslinking agent, a mordant and a nonionic surfactant while the coating layer exhibits a constant drying rate. The pH of the second coating liquid is preferably 8.5 or more, more preferably 9.0 or more,
More preferably, it is 9.2 or more. If the pH of the second coating liquid is less than 8.5, cracks may occur in the color material receiving layer.

Here, "before the coating layer starts to exhibit the rate of decrease in drying rate" usually means a few minutes immediately after the coating of the coating liquid for the colorant-receptive layer, and during this period, the coated coating layer is applied. The constant drying rate, which is a phenomenon in which the content of the solvent therein decreases in proportion to time, is shown. The time indicating the constant rate of drying is described in Chemical Engineering Handbook (p. 707 to 712, published by Maruzen Co., Ltd., October 25, 1980).

As described above, after the first coating liquid (coloring material receiving layer coating liquid) is coated, it is dried until the coating layer shows a rate of reduction drying. The drying is generally 50 to 180.
0.5 to 10 minutes (preferably 0.5 to 5 minutes) at ℃
It is carried out. As the drying time, it naturally depends on the coating amount, but the above range is suitable.

As the method of applying the second coating solution before the above-mentioned coating layer shows the decreasing rate of drying, (1) a method of further coating the coating layer with the crosslinking agent solution, (2) spraying And the like, and (3) a method of immersing the support on which the coating layer is formed in the second coating liquid (crosslinking agent solution).

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

The coating amount of the second coating liquid (crosslinking agent solution) to be applied to the color material receiving layer is 0.01 to 90% in terms of crosslinking agent.
It is generally 10 g / m ² , and preferably 0.05 to 5 g / m ² .

After application of the crosslinking agent solution, generally 40 to 18
It is heated at 0 ° C. for 0.5 to 30 minutes to be dried and cured. Above all, 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 boron compound contained in the cross-linking agent solution, it is preferable to perform heating at 60 to 100 ° C for 0.5 to 15 minutes.

The above second coating solution (crosslinking agent solution)
May be applied at the same time when the first coating liquid (coloring material receiving layer coating liquid) is applied. In this case, the color material-receptive layer coating solution and the cross-linking agent solution are simultaneously coated on the support so that the color material-receptive layer coating solution is in contact with the support (multi-layer coating), and then dried and cured to obtain the color. A material receiving layer can be formed.

The above simultaneous coating (multilayer coating) can be carried out by a coating method using an extrusion die coater or a curtain flow coater. After the simultaneous coating, the formed coating layer is dried, and the drying in this case 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 carried out by heating at 100 ° C. for 0.5 to 5 minutes. For example, when borax or boric acid is used as the 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.

When the above-mentioned simultaneous coating (multilayer coating) is carried out, for example, by an extrusion die coater, the two kinds of coating liquids discharged at the same time are in the vicinity of the discharge port of the extrusion die coater, that is, before being transferred onto the support. Is formed in multiple layers, and in that state, multiple layers are applied on the support. Since the two-layer coating solution that has been overlaid before coating tends to cause a cross-linking reaction at the interface between the two solutions when it is transferred to the support, the two solutions to be discharged are mixed near the discharge port of the extrusion die coater. May increase the viscosity, which may hinder the coating operation. Therefore, in the case of simultaneous coating as described above, along with the coating of the colorant-receptive layer coating solution and the crosslinking agent solution containing the crosslinking agent and the mordant, a barrier layer solution (intermediate layer solution) made of a material that does not react with the crosslinking agent. It is preferable to apply (3) at the same time by interposing between the above two liquids.

The barrier layer liquid can be selected without particular limitation as long as it can form a liquid film without reacting with the boron compound. For example, an aqueous solution containing a trace amount of a water-soluble resin that does not react with a boron compound, water, and the like can be given. The above-mentioned water-soluble resin is used in consideration of coatability for the purpose of a thickener and the like, and examples thereof include hydroxypropylmethylcellulose, methylcellulose, hydroxyethylmethylcellulose, polyvinylpyrrolidone, gelatin. And the like. The mordant may be contained in the barrier layer liquid.

Further, water, an organic solvent, or a mixed solvent thereof can be used as a solvent in each step.
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, toluene and the like. To be

After the color material receiving layer is formed on the support, the surface of the color material receiving layer is smoothed by applying a calendering treatment under heating and pressure through a roll nip using, for example, a super calender or a gloss calender. It is possible to improve properties, glossiness, transparency and coating film strength. However, the calendering process may cause a decrease in the porosity (that is, the ink absorbency may decrease), and therefore, it is necessary to set conditions under which the decrease in the porosity is small.

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

In the case of ink jet recording, the layer thickness of the color material receiving layer needs to be determined in relation to the porosity in the layer, since it is necessary to have an absorption capacity enough to absorb all the droplets. 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 preferable.

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

The colorant-receiving layer preferably has excellent transparency. As a guideline, the haze value when the colorant-receiving layer is formed on a transparent film support is 30.
% Or less, and more preferably 20% or less. The haze value is a haze meter (HG
M-2DP: It can be measured using Suga Test Instruments Co., Ltd.

<Support> As the support, any of a transparent support made of a transparent material such as plastic and an opaque support made of an opaque material such as paper can be used. In order to make the most of the transparency of the colorant receiving layer, it is preferable to use a transparent support or a highly glossy opaque support.

As a material which can be used for the transparent support, a material which is transparent and has a property of withstanding radiant heat when used in an OHP or a backlight display is preferable. Examples of the material include polyesters such as polyethylene terephthalate (PET); polysulfone,
Examples thereof include polyphenylene oxide, polyimide, polycarbonate and polyamide. Among them, polyesters are preferable, and polyethylene terephthalate is particularly preferable. The thickness of the transparent support is not particularly limited, but is preferably 50 to 200 μm from the viewpoint of handleability.

As the highly glossy opaque support, one having a glossiness of 40% or more on the surface on which the colorant receiving layer is provided is preferable. The glossiness is JIS P-814.
It is a value determined according to the method described in 2 (75 degree specular gloss test method for paper and board). Specific examples include the following supports.

For example, high-gloss paper supports such as art papers, coated papers, cast coated papers, and baryta papers used as silver salt photographic supports; polyesters such as polyethylene terephthalate (PET); nitrocellulose. Cellulose esters such as cellulose acetate and cellulose acetate butyrate, and plastic films such as polysulfone, polyphenylene oxide, polyimide, polycarbonate and polyamide are made opaque by containing a white pigment and the like (may be subjected to surface calendering treatment). High-gloss film; or a high-gloss film containing the above various paper supports, the above-mentioned transparent supports, or white pigments, etc., provided with a polyolefin coating layer containing or not containing a white pigment. Support. Further, a white pigment-containing expanded polyester film (for example, expanded PET in which polyolefin fine particles are contained and voids are formed by stretching) can also be preferably mentioned.

The thickness of the opaque support is not particularly limited, but it is preferably 50 to 300 μm from the viewpoint of handleability.

Further, a corona discharge treatment,
Those subjected to glow discharge treatment, flame treatment, ultraviolet irradiation treatment and the like may be used.

Next, the base paper used for the paper support will be described in detail. The base paper is made from wood pulp as a main raw material, and if necessary, synthetic paper such as polypropylene, or synthetic fiber such as nylon or polyester is used in addition to wood pulp. As the wood pulp, LBKP, LBSP, NBKP, NBSP, LD
Any of P, NDP, LUKP and NUKP can be used, but LBKP, NBSP, LB with a large amount of short fibers
It is preferable to use more SP, NDP, and LDP. However, the ratio of LBSP and / or LDP is preferably 10% by mass or more and 70% by mass or less.

As the above-mentioned pulp, chemical pulp containing few impurities (sulfate pulp or sulfite pulp) is preferably used,
Pulp that has been bleached to improve its whiteness is also useful.

In the base paper, sizing agents such as higher fatty acids and alkyl ketene dimers, white pigments such as calcium carbonate, talc and titanium oxide, paper strength enhancers such as starch, polyacrylamide and polyvinyl alcohol, fluorescent whitening agents, A water retention agent such as polyethylene glycol, a dispersant, and a softening agent such as quaternary ammonium can be appropriately added.

The freeness of the pulp used for papermaking is as follows.
According to CSF regulations, 200 to 500 ml is preferable, and
The fiber length after beating is preferably 30 to 70% of the sum of the 24 mesh residual mass% and the 42 mesh calculated mass% defined in JIS P-8207. The mass% of the 4-mesh residue is preferably 20 mass% or less.

The basis weight of the base paper is preferably 30 to 250 g, particularly preferably 50 to 200 g. The thickness of the base paper is preferably 40 to 250 μm. The base paper can be given a high smoothness by calendering at the papermaking stage or after the papermaking. The base paper density is 0.7 to 1.2 g / m ² (J
ISP-8118) is common. Furthermore, the stiffness of the base paper is 2 under the conditions specified in JIS P-8143.
0 to 200 g is preferable.

A surface sizing agent may be applied to the surface of the base paper, and as the surface sizing agent, the same sizing agent as that which can be added to the base paper can be used. The pH of the base paper is JI
It is preferably 5 to 9 when measured by the hot water extraction method specified in SP-8113.

The polyethylene for covering the front surface and the back surface of the base paper is mainly low-density polyethylene (LDPE) and / or high-density polyethylene (HDPE), but other LLDPE, polypropylene or the like can be partially used.

In particular, the polyethylene layer on the side for forming the colorant-receiving layer is formed by adding rutile or anatase type titanium oxide to polyethylene, as is commonly used in photographic printing paper, to obtain opacity and whiteness. Those improved are preferable. Here, the content of titanium oxide is preferably 3 to 20 mass% with respect to polyethylene, and 4 to 13 is preferable.
Mass% is more preferable.

The polyethylene-coated paper can be used as a glossy paper, and when polyethylene is melt-extruded on the surface of the base paper for coating, a so-called patterning treatment is performed to obtain a matte surface or a matte surface obtained by ordinary photographic printing paper. It is also possible to use those having a silk surface.

[0136]

EXAMPLES [Synthesis Example] (Synthesis Example 1) Polyallylamine (molecular weight: about 1000)
50 parts of a 10 mol / l hydrochloric acid aqueous solution was added to 570 parts of the 10% by mass aqueous solution of 0), and the mixture was stirred at room temperature for 3 hours, and water was added to adjust the concentration to obtain 10 parts of the polyallylamine partial hydrochloride (polymer 1). A mass% aqueous solution was obtained.

(Synthesis Examples 2 to 9) 570 parts of polyallylamine in Synthesis Example 1 and 50 parts of 10 mol / l hydrochloric acid are shown in Table 1.
Synthesis Example 1 except that the compound and the addition amount were changed
Polymer 3 by adjusting the concentration with water
A 10% aqueous solution of -11 was obtained.

[0138]

[Table 1]

(Example 1) -Preparation of support-Art paper (OK Kinfuji; manufactured by Oji Paper Co., Ltd.) having a basis weight of 186 g / m ² was subjected to corona discharge treatment and then subjected to high density using a melt extruder. Polyethylene was coated to a thickness of 19 μm to form a matte surface resin layer (hereinafter, the resin layer surface is referred to as “back surface”). The resin layer on the back surface is further subjected to corona discharge treatment, and then aluminum oxide (alumina sol 100, manufactured by Nissan Chemical Industries, Ltd.) and silicon dioxide (Snowtex O, as an antistatic agent).
A dispersion liquid obtained by dispersing in a ratio of 1: 2 (manufactured by Nissan Chemical Industries, Ltd.) in water (mass ratio) was applied so that the dry mass would be 0.2 g / m ² .

Further, after the corona discharge treatment was applied to the felt surface (front surface) side where the resin layer was not provided, anatase type titanium dioxide 10%, a trace amount of ultramarine blue, and an optical brightening agent 0.01% ( To polyethylene), MFR
(Melt float) 3.8 low-density polyethylene is melt-extruded using a melt extruder to a thickness of 24 μm, and a high-gloss thermoplastic resin layer is formed on the surface side of the base paper (hereinafter referred to as “high-gloss surface”). Is referred to as "surface"), and was used as a support. The surface of the support was used after being subjected to corona discharge treatment before applying the coating liquid.

-Preparation of Inorganic Fine Particle Dispersion- (2) Ion-exchanged water in the following composition was mixed with (1) vapor-phase method silica fine particles, and (3) 10% of the polymer 1 according to the present invention was mixed.
Aqueous solution was further added, by using nanomizer LA31 (Nanomizer Co., Ltd.), after the two treatment at a pressure of 500 kg / m ^2, further subjected to stirring for 60 minutes, in the following composition (4) polyvinyl 8% alcohol aqueous solution,
(5) Emulgen 109P and (6) diethylene glycol monobutyl ether were added to prepare a coating liquid (first coating liquid) A for the colorant receiving layer. The mass ratio of the silica fine particles to the water-soluble resin (PB ratio / (1) :( 4)) is 4.5:
It was 1. [Composition of coating liquid A for colorant receiving layer] (1) Fine particles of vapor-phase method silica (inorganic pigment fine particles) 7.7 parts (QS-30, manufactured by Tokuyama Corp .; specific surface area according to BET method: 300 m ² / g) , Average primary particle diameter 7 nm) (2) Ion-exchanged water 68.8 parts (3) Polymer 1 10% aqueous solution 3.85 parts (4) Polyvinyl alcohol 8% aqueous solution 21.3 parts (PVA124, Kuraray Co., Ltd.) Manufactured, saponification degree 98.5%, degree of polymerization 2400) (5) Polyoxyethylene lauryl ether 10% aqueous solution 1.0 part (Emulgen 109P, manufactured by Kao Corporation) (6) Diethylene glycol monobutyl ether 0.6 part

[Evaluation] (Viscosity) 300 g of the above coating solution was sampled in a 500 cc container and immersed in a high temperature bath at 30 ° C. for 10 minutes, and then the viscosity was measured at 60 rpm using a B type viscometer (manufactured by Tokimec). did. AA: 0.1 Pa · s (100 cp) or less, coatable and good dispersion state BB: less than 1 Pa · s (1000 cp), dispersion state CC: 1 Pa · s (1000 cp) or more , Dispersed state that cannot be applied

(Average particle size) The volume-based median particle size D50 was measured using a light scattering diffraction type particle size distribution measuring device (LA910, manufactured by Horiba Ltd.), and this value was adopted as the average particle size. did. In addition, in the measurement, the refractive index 1.10 was input as a parameter. AA: 0.2 μm or less BB: Less than 5 μm CC: 5 μm or more

(Coarse particles) In the above particle size measurement, 5 μ
The evaluation was made by the ratio of particles of m or more in the whole. AA: 2% or less BB: less than 10% CC: 10% or more

(Examples 2 to 7, Comparative Examples 1 to 11) In the same manner as in Example 1, Examples 2 to 7 and Comparative Examples 1 to 11 of the coating solution for the colorant receiving layer were prepared and evaluated. The results are shown in Table 2.
Summarized in. In Comparative Examples 7 to 11, the pH of the coating solution was adjusted with hydrochloric acid or ammonia water.

[0146]

[Table 2]

From Table 2, the polymer according to the present invention has a pH of 4.
In the range of 5 to 7, it is possible to suppress the aggregation of the inorganic pigments and to give a dispersion having good fluidity. In Table 2, with respect to the dispersion liquid having a rating of BB or higher, an inkjet recording sheet was prepared as follows.

(Example 8) -Preparation of ink-jet recording sheet-The coating material A for colorant-receiving layer was applied on the surface of a support at a coating amount of 200 ml / m ² using an extrusion die coater, 80 ° C with hot air dryer (wind speed 3-8m /
sec), the coating layer was dried until the solid content concentration became 20%. The coating layer showed a constant drying rate during this period. Immediately after that, the cross-linking agent solution (second coating solution) A having the following composition
20 g / m ² was adhered on the coating layer by dipping for 2 seconds, and further dried at 80 ° C. for 10 minutes. From this, an ink jet recording sheet of the present invention provided with a coloring material receiving layer having a dry film thickness of 32 μm was produced.

[0149] [Composition of Crosslinking Agent Solution A] Boric acid (crosslinking agent) 2.5 parts Ion-exchanged water 69.5 parts Polyallylamine (molecular weight 10,000) 10% aqueous solution 25 parts Polyoxyethylene lauryl ether 2 parts Ammonium chloride 1 part

-Evaluation Method- (1-1) Ink Absorption Rate Using an ink jet printer (PM-900C, manufactured by Seiko Epson Corp.), Y (yellow), M (magenta) and C were formed on the ink jet recording sheet. (Cyan), K
Solid images of (black), B (blue), G (green) and R (red) are printed, and immediately (after about 10 seconds), the paper is contact-pressed on the image to transfer the ink to the paper. The presence or absence of each of these was evaluated according to the following criteria. [Standard] AA: Ink transfer onto paper was not observed at all.
It shows that the ink absorption rate is good. CC: Partial transfer of the ink onto the paper was observed.

(1-2) Occurrence 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. [Standard] AA: No cracks were observed on the surface. BB: A crack having a length of 1 to 2 mm was recognized. CC: A crack having a length of 3 mm or more was recognized.

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

(1-4) Blurring with Time Using the same printer as in (1-1) above, a grid-like linear pattern (line width 0. Two
8 mm) was printed, and the visual density was measured by X-light 310TR (manufactured by X-light). Furthermore, after printing for 3 hours, the product was stored in a thermo-hygrostat at 40 ° C. and a relative humidity of 90% for 1 day, and the visual density was measured again to calculate the density difference (ΔOD). The smaller the value of the density difference (ΔOD), the more the generation of bleeding with time is suppressed. AA: No bleeding over time was observed BB: Some bleeding over time was observed, but a level at which some problems occur in practical use

(1-5) Lightfastness Using the same printer as in (1-1) above, solid Y (yellow), M (magenta), C (cyan) and K (black) inks are formed on an ink jet recording sheet. Print the image, X light 3
The visual density of each color was measured by 10TR (manufactured by X-Light Co., Ltd.). After that, 365n for the printed image
Xenon weather-ometer Ci through a film that blocks ultraviolet rays in the wavelength range of m or less
Using 65A (manufactured by ATLAS), the lamp was lit for 3.8 hours under the environmental conditions of 25 ° C. and relative humidity of 32%, and then the lamp was extinguished at 20 ° C. and relative humidity of 91%. A cycle of standing underneath for 1 hour was carried out for 11 days. Then, the visual density of each color was measured again, and the fading of each color was evaluated by calculating the residual rate (the rate of change in density before and after the test). AA: Level of fading is small and good (remaining rate of 70% or more) BB: Fading is observed, but a level causing some problems in practical use (remaining rate of 70% or less)

(1-6) Printing Density An inkjet printer (PM-900C, manufactured by Seiko Epson Corp.) was used to print a solid K (black) image on an inkjet recording sheet, and after standing for 3 hours, the printing was performed. The reflection density of the surface was measured with an X-light densitometer. AA: High density, good image was obtained BB: Low density, but a level at which some problems occur in practical use

(Examples 9 to 14) Ink jet recording was carried out in the same manner as in Example 8 except that the coloring material receiving layer coating solution in Example 8 was changed to the coloring material receiving layer coating solutions in Examples 2 to 7, respectively. A sheet was prepared and evaluated in the same manner.

(Comparative Examples 12 to 15) The coating liquids for the colorant-receptive layer in Example 8 were respectively prepared in Comparative Examples 1, 6, 8, and 11.
An ink jet recording sheet was prepared and evaluated in the same manner as in Example 8 except that the coating liquid for the colorant receiving layer was changed to.

The results of evaluation of these are shown in Table 3.

[0159]

[Table 3]

From Table 3, in the ink jet recording sheet using the dispersion according to the present invention, generation of bleeding with time was not recognized, and the print density was excellent. In addition, good results were obtained with respect to the ink absorption rate, cracking of the recording sheet surface, water resistance, and light resistance. On the other hand, none of the recording sheets using the dispersion liquid having a large particle size, to which the unneutralized polyamine was added, had excellent print density. Further, the recording sheet using the dispersion liquid in which the cationic polymer was added favorably was excellent in printing density, but was inferior in blurring with time and light resistance.

[0161]

The ink jet recording sheet using the dispersion of the present invention is strong without cracks and the like, has good ink absorptivity, is excellent in image density, and has light resistance and water resistance in the image area. It is possible to provide an inkjet recording sheet which has excellent gas resistance and does not cause blurring over time even when stored for a long time in a high temperature and high humidity environment.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2C056 EA13 FC06                 2H086 BA15 BA31 BA33 BA34 BA35                       BA37 BA41 BA45 BA46

Claims (15)

[Claims] 1. An inkjet recording sheet having a colorant receiving layer on the surface of a support, wherein the colorant receiving layer contains at least inorganic pigment fine particles and an agglomeration inhibitor, and the inorganic fine particles have a pH of more than 4.5. An ink jet recording sheet, characterized by being coated with a dispersion liquid. 2. The ink jet recording sheet according to claim 1, wherein the aggregation preventing agent is made of a polymer having at least a unit represented by the following general formula (1). [Chemical 1] [In the general formula (1), X ⁻ represents a counter anion, and m represents 0 or 1. ] 3. The agglomeration inhibitor is a polymer (a) having at least an ammonium salt unit represented by the following general formula (1) and a unit represented by the following general formula (2). The inkjet recording sheet according to claim 1 or 2. [Chemical 2] [In general formulas (1) and (2), X ⁻ represents a counter anion,
m and n represent 0 or 1. ] 4. The polymer (a) is the compound represented by the general formula (2).
The inkjet recording sheet according to claim 3, which is obtained by reacting a polymer (b) having a unit represented by: with an acid. 5. The polymer (b) is the compound represented by the general formula (2).
The inkjet recording sheet according to claim 4, wherein the sheet is composed of only a unit represented by or a derivative thereof. 6. The ink jet recording sheet according to claim 1, wherein the color material receiving layer further contains a water-soluble resin. 7. The ink jet recording sheet according to claim 6, wherein the color material receiving layer further contains a crosslinking agent capable of crosslinking the water-soluble resin. 8. The ink jet recording sheet according to claim 7, wherein the crosslinking agent is a boron compound. 9. The ink jet recording sheet according to claim 1, wherein the color material receiving layer further contains an organic mordant capable of fixing an anionic dye. 10. The ink jet recording sheet according to claim 9, wherein the organic mordant is polyallylamine or a derivative thereof. 11. The inorganic pigment fine particles are silica fine particles having an average primary particle diameter of 20 nm or less, or pseudoboehmite having an average pore radius of 1 to 10 nm. 2. An ink jet recording sheet according to item 1. 12. The water-soluble resin is polyvinyl alcohol or its derivative.
12. The inkjet recording sheet according to any one of 1 to 11. 13. The coloring material receiving layer has a porosity of 50 to 8
It has a three-dimensional network structure of 0% and the mass ratio (i: p) of the inorganic pigment fine particles (i) and the water-soluble resin (p) is 1.
It is 5: 1-10: 1, The inkjet recording sheet as described in any one of Claim 6 to 12 characterized by the above-mentioned. 14. The coloring material-receptive layer applies a first coating liquid containing the inorganic pigment fine particles, the water-soluble resin and the aggregation inhibitor to the surface of the support, and (1) applying the coating liquid. At the same time, either (2) during the drying of the coating layer formed by the coating and before the coating layer shows a reduction rate drying, or (3) after drying the coating layer to form a coating film. The inkjet recording sheet according to any one of claims 1 to 13, which is formed by applying a second coating liquid containing an organic mordant. 15. The coloring material receiving layer is provided by adding the crosslinking agent to at least one of the first coating liquid and the second coating liquid, or the first coating liquid and the second coating liquid. 15. The ink jet recording sheet according to claim 1, which is obtained by applying a coating liquid containing the cross-linking agent separately from the above.