JP2003335048A - Ink jet recording paper and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink jet recording paper which decreases a crack trouble on a surface layer and is excellent in fading resistance due to noxious gas even if it is preserved under low humidity environment, and to provide its manufacturing method. <P>SOLUTION: The ink jet recording paper is provided with the surface layer containing an organic fine particle A or an organic fine particle B and a porous layer, and the surface layer or the porous layer contains a cationic activator. The organic fine particle A is an organic fine particle insoluble in water and soluble in or swollen by a water soluble organic solvent of 18.414-30.69 (MPa)<SP>1/2</SP>in SP value and ≥120°C in boiling point, and ≥70°C in Tg and ≤100 nm in average particle size. The organic fine particle B is an organic fine particle of ≥70°C in Tg and ≤100 nm in average particle size, having a polymer containing the repeating unit given in general formula (1) of ≥5 mass%. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet recording paper (hereinafter also simply referred to as recording paper) and a method for producing the same, and more specifically, it has excellent coating film physical properties (crack failure resistance) and is stored in a low humidity environment. In particular, the present invention relates to an inkjet recording paper excellent in resistance to discoloration due to harmful gas and a method for manufacturing the same.

[0002]

2. Description of the Related Art Inkjet recording is a technique for ejecting minute droplets of ink by various operating principles and adhering them to recording paper to record images, characters, etc. It has advantages such as easy colorization.

In particular, recently, since the image quality of printers has advanced and has reached the photographic image quality, the recording paper also realizes the photographic image quality, and the texture of the silver salt photograph (gloss, smoothness,
It is required to reproduce).

As one of the methods for reproducing the texture of silver salt photographs, a so-called swelling type in which a hydrophilic binder such as gelatin or polyvinyl alcohol is coated on a support as a recording sheet is known. This method has drawbacks such as a low ink absorption speed, the surface tends to be sticky after printing, and the image is easily blurred due to the influence of humidity during storage. In particular, since the ink absorption speed is slow, the ink droplets mix with each other before they are absorbed, which easily causes bleeding between different colors (bleeding) and color unevenness (beading) within the same color, which makes the silver salt photographic image quality Achievement is very difficult.

The so-called swelling type is becoming the mainstream instead of the swelling type, which is a so-called void type, and is characterized by a high absorption speed because ink is absorbed in fine voids. Examples of the recording paper which achieves the image quality of silver salt photographs and the texture of silver salt photographs as described above are disclosed in JP-A-10-119423 and 10-1.
19424, 10-175364, 10-19.
No. 3776, No. 10-193776, No. 10-217.
No. 601, No. 11-20300, No. 11-10669.
No. 4, No. 11-321079, No. 11-348410.
No. 10-178126, No. 11-348409.
No. 2000-27093, 2000-9483.
0, 2000-158807, 2000-2112
41, etc.

On the other hand, in addition to the image quality and texture, the requirements for durability and image storability have become higher, and many attempts have been made to reach the silver salt photographic level in light resistance, moisture resistance, water resistance and the like. As an example of improving the light resistance, Japanese Patent Application Laid-Open No. Sho 5
7-74192, 57-87989, 57-7
No. 4193, No. 58-152072, No. 64-364
79, JP-A-1-95091, 1-115677.
No. 3, No. 3-13376, No. 4-7189, No. 7-1.
No. 95824, No. 8-25796, No. 11-3210.
No. 90, No. 11-277893, JP 2000-37.
951 and many other techniques have been disclosed.

The void type recording paper has not only the light resistance but also the problem that the void structure is likely to cause discoloration due to harmful gas. In particular, it is likely to occur with a phthalocyanine-based water-based dye used in a general color inkjet printer.

Although the mechanism of this discoloration has not been clarified yet, since the fine void structure has a high surface area and the inorganic fine particles used have an active surface, ozone, oxidant, It is speculated that a very small amount of active harmful gas in the air such as SOx and NOx decomposes the dye.

Regarding the technique for improving the phenomenon of discoloration and fading,
For example, JP-A-63-252780 and 64-118.
77, JP-A-1-108083, 1-21-2688.
No. 1, No. 1-218882, No. 1-258980,
2-188287, 7-237348, 7-
No. 266689, No. 8-164664, etc., but since the recording paper of photographic image quality, which has a finer void structure, is more likely to be deteriorated, the conventional improving technique is not effective in improving. It is sufficient and more drastic improvement is desired.

One of the countermeasures against the above problems is to improve by using a swelling type recording paper, but it is very difficult to improve the slowness of the ink absorption speed which is an essential problem. Is.

The ink jet recording method using pigment ink can solve the problem of discoloration to some extent, but the characteristics such as glare (bronzing) on the recording paper have not reached a level at which sufficient image quality is provided. The current situation. In addition, as another method, laminating the print or putting it in a frame, etc.
Alternatively, JP-A-53-27426 and JP-A-59-222381.
No. 62-271781, JP-A-11-15720.
7, 11-245507, JP 2000-716.
The method disclosed in No. 08, in which a recording paper containing thermoplastic fine particles on its surface is printed and then subjected to heat or pressure treatment to develop a gas barrier layer, is very effective. Processing is required and extra steps are a burden. In particular, in large-format ink jet recording with a width of 60 cm or more, not only laminating and heat roll processing are troublesome, but also dedicated equipment becomes large,
It is expensive and hard to say that it is widespread.

Further, JP-A-63-60784 discloses an ink jet recording paper having a void layer containing organic fine particles and inorganic fine particles. However, since these organic fine particles are soluble only in a special solvent and not in an organic solvent used in general inkjet printer inks, they cannot be used for ordinary inkjet recording under the present circumstances. is there.

The present inventors have previously found that the inclusion of specific organic fine particles in the coating layer of a recording paper is very effective in preventing discoloration. In particular, it is effective to make the surface layer contain these organic fine particles at a high concentration.

However, as a result of further studies, in the case of the above-mentioned constitution, the surface layer of the formed thin film is apt to be cracked at the time of coating and drying. It was found that the anti-fading effect cannot be exerted. Further, it has been found that when the printed recording paper is stored at a low temperature, the fading prevention effect tends to be lost.

[0015]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to reduce coating failure (crack failure) of the surface layer that exhibits the effect of preventing fading and fading. An object of the present invention is to provide an inkjet recording paper excellent in resistance to discoloration due to harmful gas even when stored below and a manufacturing method thereof.

[0016]

The above object of the present invention can be achieved by the following constitutions.

1. A support has a surface layer containing the organic fine particles A or the organic fine particles B defined above and one or more porous layers, and at least one of the surface layers or the porous layers is cationic. An inkjet recording sheet containing a surfactant.

2. In an inkjet recording paper having a surface layer containing the organic fine particles A or the organic fine particles B defined above on a support and one or more porous layers, the surface layer is emulsion-polymerized An ink jet recording sheet containing fine particles A or organic fine particles B and a cationic surfactant.

3. A method for producing the inkjet recording paper according to 1 or 2 above, which comprises applying one or more porous layers on a support and drying, and then applying and drying the surface layer to produce the inkjet recording paper. A method for producing a characteristic inkjet recording paper.

4. 3. A method for producing an inkjet recording paper according to 1 or 2 above, which is characterized in that one or more porous layers and a surface layer are simultaneously coated on a support and dried to produce the inkjet recording paper. Manufacturing method.

The inventors of the present invention have made extensive studies in view of the above problems, and as a result, as an ink jet recording paper, a surface layer containing the organic fine particles A or organic fine particles B defined above and one or more porous layers. And at least one layer of the surface layer or the porous layer contains a cationic surfactant, and further, the surface layer is emulsion-polymerized. By containing B and a cationic surfactant, coating failure (cracking failure) on the surface layer is reduced, and an inkjet recording paper with excellent discoloration resistance against harmful gas even when stored in a low humidity environment is realized. It is a finding of what can be done.

In the above-mentioned constitution, it is important that the surface layer containing a thin layer of organic fine particles is uniformly applied on the support without any coating failure in order to sufficiently exert the effect of preventing fading. In the environment where cracks are likely to occur due to the fact that it is a layer or the filling rate of organic fine particles or inorganic fine particles is high, and in the case of a coating failure such as the above-mentioned cracks, the original anti-fading effect is provided. It becomes difficult to demonstrate. In particular, when the recording paper printed under a low humidity environment is stored, the effect of preventing discoloration tends to decrease.

Although the mechanism by which the above-mentioned effect is exhibited by the structure according to the present invention is not clear, it is presumed as follows. That is, when a cationic surfactant is used, a remarkable prevention effect is exhibited against the deterioration of the coating film physical properties and the discoloration / fading prevention effect under low humidity. This is because the dyes in the ink are generally anionic and will temporarily form a complex with the cationic surfactant. This complex makes it easy to hold the organic solvent in the ink at or near the surface layer even under low humidity, and as a result, the organic fine particles contained therein are efficiently fused or formed into a film by the ink solvent, and the gas barrier layer is formed. I think that is formed stably. On the other hand, in the case of containing a surfactant other than the cationic surfactant, for example, an anionic surfactant, a nonionic surfactant or a betaine-type surfactant, a complex with a dye as described above is used. It is difficult to form, and it is considered that the solvent in the ink is not sufficiently retained in the surface layer under low humidity, so that the gas barrier layer forming ability is reduced and the anti-fading effect under low humidity is reduced. Furthermore, it has been found that even when a small amount of a surfactant other than the cationic surfactant is contained, the effect of preventing discoloration can be stably obtained by containing the cationic surfactant even under low humidity.

Further, a cationic compound such as a cationic polymer or a water-soluble polyvalent metal compound is used in the ink receiving layer in order to fix and immobilize the dye in the ink.
When an anionic surfactant is used, when the surface layer is applied on the porous layer, cohesion easily occurs between the layers, or when a nonionic surfactant is used, the coating / drying step is performed. It was found that the film property deteriorates and cracks are likely to occur.

The details of the present invention will be described below. In the invention according to claim 1, a surface layer containing the organic fine particles A or the organic fine particles B defined above on a support,
One or more porous layers, and at least one layer of the surface layer or the porous layer is characterized by containing a cationic surfactant, and in the invention according to claim 2,
In an inkjet recording paper having a surface layer containing the organic fine particles A or the organic fine particles B defined above on a support and one or more porous layers, the surface layer is emulsion-polymerized It is characterized by containing the fine particles A or the organic fine particles B and a cationic surfactant.

First, the details of the organic fine particles A and the organic fine particles B used in the surface layer according to the present invention will be described.

The organic fine particles A according to the present invention are insoluble in water which has an SP value of 18.414 to 30.69 (MPa) ^1/2 and is dissolved or swollen by a water-soluble organic solvent having a boiling point of 120 ° C. or higher. Of organic fine particles having a glass transition temperature (Tg) of 70 ° C. or higher and an average particle diameter of 100 nm or less.

In the present invention, SP (Solubility)
Parameter) is a solubility parameter and is a useful measure for predicting the solubility of a substance. The unit of SP value is represented by (MPa) ^1/2 and indicates the value at 25 ° C.

Regarding the SP value of the organic solvent, for example,
"POLYMER HANDBOOK" (J. Bran
drup et al., A Wiley-interscience
(CePublication), page IV-337, as well as various publications.

Examples of water-soluble organic solvents (representative SP values shown in parentheses) that can be used in the present invention are:
Alcohols (eg, butanol (23.3), isobutanol (21.5), secondary butanol (2
2.1), tertiary butanol (21.7), pentanol, hexanol, cyclohexanol (23.
3), benzyl alcohol (24.8), etc., polyhydric alcohols (for example, ethylene glycol (29.9),
Diethylene glycol (24.8), triethylene glycol (21.9), polyethylene glycol, propylene glycol (25.8), dipropylene glycol (20.5), polypropylene glycol, butylene glycol, hexanediol (21.1), Pentanediol, glycerin (33.8), hexanetriol, thiodiglycol, etc., alkyl ethers of polyhydric alcohols (for example, ethylene glycol monomethyl ether (23.3), ethylene glycol monoethyl ether (21.5), Ethylene glycol monobutyl ether, ethylene glycol dimethyl ether (17.
6), diethylene glycol monomethyl ether (2
3.3), diethylene glycol monoethyl ether,
Diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol monoethyl ether, triethylene glycol monomethyl ether,
Triethylene glycol monobutyl ether, triethylene glycol diethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol monomethyl ether, tetraethylene glycol monoethyl ether, tetraethylene glycol monobutyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, etc.), amine Kinds (for example, ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine,
N-ethyldiethanolamine, morpholine, N-ethylmorpholine, ethylenediamine (25.2), diethylenetriamine, triethylenetetramine, tetraethylenepentamine, polyethyleneimine, pentamethyldiethylenetriamine, tetramethylpropylenediamine, etc., amides (eg formamide) , N, N-dimethylformamide, N, N-dimethylacetamide, etc.), heterocycles (eg, 2-pyrrolidone, N-methyl-2-pyrrolidone, cyclohexylpyrrolidone, 2-oxazolidone, 1,3-dimethyl-2-). Examples thereof include imidazolidinone), sulfoxides (eg, dimethyl sulfoxide), sulfones (eg, sulfolane).

In the present invention, particularly preferred water-soluble organic solvents are polyhydric alcohols, alkyl ethers of polyhydric alcohols, and heterocycles, from which 2-3
It is preferable to select a kind.

The SP value according to the present invention is 18.414-3.
As the water-soluble organic solvent in the range of 0.69, ethylene glycol, diethylene glycol, triethylene glycol, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, triethanolamine, 2-pyrrolidone, etc. are preferably used,
Particularly preferably used is diethylene glycol monobutyl ether (SP value 19.437, boiling point 230
℃).

The water-soluble organic solvent according to the present invention has a boiling point of 1
A material having a temperature of 20 ° C or higher is selected. The upper limit of the boiling point is not particularly limited, but one having a melting point of 30 ° C. or lower is preferable.

The organic fine particles A according to the present invention have an SP value of 1
8.414-30.69 (MPa) ^1/2And the boiling point is
Dissolved or swollen by the water-soluble organic solvent above 120 ° C
Water-insoluble organic fine particles and glass transition temperature
(Tg) is 70 ° C. or higher, and average particle size is 100 nm or less
And has a weight average molecular weight of 50.
A polymer of 00 or more is preferable, and its material is, for example,
For example, polyvinyl chloride, polyvinylidene chloride, polyacrylic
Rate, polymethacrylate, elastomer, ethylene
-Vinyl acetate copolymer, styrene- (meth) acrylic copolymer
Polymer, polyester, polyvinyl ether, polyvinyl
Luacetal, polyamide, polyurethane, polyolefin
In, SBR, NBR, polytetrafluoroethylene,
Chloroprene, protein, polysaccharide, rosin ester,
It is selected from conventionally known ones such as shellac resin. Especially good
The material of the organic fine particles A is preferably polyvinyl acetal.
Resin, polyurethane resin, rosin ester resin,
(Meth) acrylate resin, SBR, etc.
Resins composed of two or more monomers by copolymerization are also preferred.
Used with a specific modifying group added to the resin
It is also possible to remove the leaving group or a mixture of two or more materials.
To form organic fine particles, and more than two kinds
You may mix and use an organic fine particle.

“Soluble with an organic solvent” in the present invention
Means that the organic fine particles A and the water-soluble organic solvent in the ink form a single phase in an equilibrium state, and "swells with the organic solvent" means that the organic fine particles A absorb the same water-soluble organic solvent. To increase the volume. The preferred volume increase rate when swollen is 2 to 8 times.

The organic fine particles A according to the present invention must be insoluble in water because they do not dissolve in ink jet recording. However, it is allowed to absorb water within a range that does not interfere with the ink absorption rate. 2 for the mass of the organic fine particles A
It may absorb up to 0% by weight of water. Further, the organic fine particles A according to the present invention need only be contained in such an amount that the organic fine particle A-containing layer is softened after printing with a pigment ink, but preferably 50% by mass or more based on the solid content in the layer. And more preferably 75% or more.

A crosslinking agent may be used in the organic fine particles A according to the present invention within a range that does not hinder dissolution or swelling in a water-soluble organic solvent. In the present invention, a conventionally known crosslinking agent can be appropriately selected and used as the crosslinking agent regardless of whether it is an organic substance or an inorganic substance.

The average particle diameter of the organic fine particles A according to the present invention has a great influence on the surface gloss of the recording paper. One feature of the present invention is that it is 100 nm or less, but a preferable average particle diameter is 1 to 100 nm, and more preferably 5 to 100 nm. When the average particle diameter of the organic fine particles A is 5 to 100 nm, it can greatly contribute to the effect of the present invention that the difference in glossiness between the printed portion and the non-printed portion is reduced. As a method of measuring the average particle diameter, for example, the cross section or the surface of the organic fine particle-containing layer is observed with an electron microscope, the particle diameters of a large number of arbitrary organic fine particles A are calculated, and the simple average value (number average) thereof is calculated. There is a way. It should be noted that each particle size is represented by a diameter assuming a circle having the same projected area. Alternatively, as another method, the organic fine particles A may be dispersed in an appropriate dispersion medium and the particle size may be determined by laser diffraction / scattering particle size distribution measurement. The shape of the organic fine particles A according to the present invention does not have to be a spherical shape, and may be needle-like or plate-like. The particle size is calculated from the volume in terms of sphere.

Next, the organic fine particles B according to the present invention will be described. The organic fine particles B referred to in the present invention means that the repeating unit represented by the general formula (1) is used as a copolymer component.
Having a polymer content of not less than mass%, having a glass transition temperature (Tg) of not less than 70 ° C., and an average particle diameter of 100 nm
The following organic fine particles are defined.

The details of the repeating unit represented by the general formula (1) will be described below. From the viewpoint of preferably exhibiting the desired effects of the present invention, the repeating unit represented by the general formula (1) as the organic fine particles B preferably has hydrophilicity. It can be obtained by polymerizing a hydrophilic monomer such as a polymer, an acrylamide monomer and / or a methacrylamide monomer, but the present invention is not limited thereto.

[0041]

[Chemical 2]

[0042]

[Chemical 3]

[0043]

[Chemical 4]

The hydrophilicity is imparted to the repeating unit represented by the general formula (1) in each partial structure of X, J, the substituent Y and the like forming the general formula (1). However, in the present invention, it is preferable that the substituent Y imparts hydrophilicity.

Further, as the substituent used for imparting hydrophilicity to the repeating unit represented by the general formula (1), "Structure-activity relationship of drug (guideline for drug design and mode of action)" is given. (Chemical region special issue No. 122) Structure-activity relationship social gathering, edited by Nankodo (1980), p96 to 103, a hydrophobic parameter (π) has a negative substituent, and the like.

The organic fine particles B according to the present invention are required to have the specific repeating unit represented by the general formula (1) as a copolymerization component in an amount of 5% by mass or more, but 10% by mass or more is contained. Preferably.

The organic fine particles B themselves are preferably hydrophilic but not water-soluble.
It is preferable to adjust the content in the range of less than 50% by mass.

Specific examples of the polymer containing 5% by mass or more of the repeating unit represented by the general formula (1) as a copolymerization component, which is used as a constituent component of the fine fine particles B according to the present invention, will be shown below. The present invention is not limited to these.

[0049]

[Chemical 5]

[0050]

[Chemical 6]

On the other hand, as the other monomer component of the polymer constituting the organic fine particles B, any conventionally known one having an ethylenically unsaturated group is selected. These may be a single type or a plurality of types. Examples of such a monomer include alkyl ester or alkyl amide of acrylic acid or methacrylic acid, and methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butyl acrylate, n-butyl methacrylate, i. -Butyl acrylate, i-butyl methacrylate, t-butyl acrylate, t-butyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, lauryl acrylate, lauryl methacrylate, styrene, vinyltoluene, α-methylstyrene ,
Vinyl acetate, acrylonitrile, methacrylonitrile,
Alternatively, acrylic acid, methacrylic acid, fumaric acid, itaconic acid, maleic acid, or dimethylaminomethyl acrylate, diethylaminomethyl acrylate, dibutylaminomethyl acrylate, dihexylaminomethyl acrylate, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, (t- Butyl) aminoethyl acrylate, diisohexylaminoethyl acrylate, dihexylaminopropyl acrylate,
Examples thereof include di (t-butyl) aminohexyl acrylate. Of these, styrene, methyl methacrylate and n-butyl acrylate are preferably used.

The organic fine particles B according to the present invention are preferably prepared as an aqueous emulsion to form a coating solution, and in that case, the ionicity of the emulsion particles is equal to or nonionic with the coating solution. preferable. The ionicity of the coating liquid for the layer containing the organic fine particles B is
It is preferably equal to or nonionic with the ionicity of the coating liquid of the other layer. Most preferably, the organic fine particles B and the coating liquid are all ionic or cationic.

Normally, the ink jet recording paper is used at room temperature, but the storage condition before use is not always room temperature, and in particular, in a closed car in the summer, it becomes a very high temperature condition. It is desired that it can be used without any trouble even after passing through such an environment. Therefore, the glass transition temperature (Tg) of the organic fine particles B needs to be 70 ° C. or higher, preferably 80 ° C. or higher, and more preferably 90 ° C. to 120 ° C.

When the glass transition temperature (Tg) of the organic fine particles A and the organic fine particles B is less than 70 ° C., fusion of the organic fine particles due to heating is likely to occur, and as a result, voids on the surface of the recording paper are generated. It is reduced or decreased, and the ink absorption speed is likely to be reduced.

Here, the Tg of the polymer which is a constituent component of the organic fine particles according to the present invention is calculated by the mass fraction from the Tg of the monomer homopolymer as the copolymerization component and the monomer composition ratio. Is possible. For example, styrene (homopolymer Tg = 100 ° C. = 373K): n-butyl acrylate (homopolymer Tg = −54 ° C. = 219K).
Tg of a polymer having a composition of 4: 1 (mass ratio) is 1 / ((1 / 373K) × 4/5 + (1/219
K) × 1/5) = 327K (= 54 ° C.).
For the Tg of the monomer homopolymer, see POLYMER
HANDBOOK (A WILEY-INTERSC
Many measurement values are published in IENCE PUBLICATION).

The average particle size of the organic fine particles B is 100.
It is necessary to be less than or equal to nm, but preferably 60 n
m or less, more preferably 20 to 40 nm, and the organic fine particles B according to the present invention are preferably synthesized in water by a conventionally known emulsion polymerization method or the like. The particle diameter is from about 20 nm to 100 nm according to a conventionally known method such as adjusting the kind and amount of the emulsifier and the monomer component.
It can be adjusted to a range of up to a degree.

In order to remarkably exert the effect of the present invention, the content of the organic fine particles A or B in the surface layer disposed on the surface of the ink absorbing layer is preferably 50 to 90% by mass. From the viewpoint of effectively preventing the fusion of the organic fine particles with each other and further increasing the ink absorption rate, the same inorganic fine particles as those used in the ink absorbing layer described later may be contained.

The ink jet recording paper of the present invention is characterized by having a surface layer containing the organic fine particles A or the organic fine particles B, but the surface layer in the present invention is limited to the outermost surface layer. There is no particular limitation, and there is no particular limitation as long as the effect of the present invention is exhibited.

Preferred constitutional examples for clearly indicating the surface layer in the present invention are listed below, but the layer constitution according to the present invention is as follows:
It is not limited to these.

1: Structure having a void-type ink absorbing layer on a support, and the layer containing the organic fine particles A or organic fine particles B thereon is the outermost layer. Structure 2: Void-type ink absorbing on the support. A layer having a layer on which the organic fine particles A or the organic fine particles B are contained,
Structure 3: a thin layer for improving the physical properties of the surface is further provided thereon: A layer having a void-type ink absorbing layer on a support and containing organic fine particles A or organic fine particles B thereon Is provided
Further, a thin layer having an ultraviolet absorbing function is provided thereon for the purpose of blocking harmful light. Structure 4: A void-type ink absorbing layer is provided on the support, and the organic fine particles A or the organic fine particles B are provided thereon. Provide the layers included,
Structure 5 further comprising a layer containing a matting agent thereon: A void-type ink absorbing layer is provided on the support, and a layer containing the organic fine particles A or the organic fine particles B is provided thereon.
A structure in which a releasable layer is further provided thereon.

The most preferable constitution among the constitution examples described above is the case where the containing layer of the organic fine particles A or the organic fine particles B according to the item 1 which can most exert the effect of the present invention is the outermost layer.

The surface layer containing the organic fine particles A or the organic fine particles B according to the present invention may contain the same inorganic fine particles and binder component as those used in the ink absorbing layer described later.

Next, the cationic surfactant contained in at least one of the surface layer containing the organic fine particles or the porous layer described later will be described.

Examples of the cationic surfactant used in the present invention include cetyltrimethylammonium salt, cetylpyridinium ammonium chloride, dimethylalkylbenzylammonium salt, benzalkonium chloride, dodecylamine salt, trimethylaminoethylalkylamide halogenide and alkyl. Pyridinium salts, other alkylamine salts, ethanolamines, polyoxyethylene-added amines and other primary to tertiary amine hydrochlorides and acetates, and further quaternary ammonium salts thereof, etc. And a surface active agent.

Further, in the present invention, a cationic fluorine-based surfactant can be used, and a compound represented by the following general formula (FK) is preferable.

General formula (FK) Rf'-L-X ⁺ Z ^{-In the} formula, Rf 'represents a hydrocarbon group having 1 to 20 carbon atoms, and at least one hydrogen atom is substituted with a fluorine atom. L represents a chemical bond or a divalent group. X ⁺ represents a cation and Z ⁻ represents a counter anion.

As an example of Rf ', -C _m F _{2m + 1} , -C _m
F2m-1 (m = 2 to 20, particularly preferably 3 to 12) and the like can be mentioned.

As an example of L, --SO₂N (R₁) (CH
₂)_p-, -CON (R₁) (CH₂) _p-, -OArSO₂
N (R₁) (CH₂)_p-, -OArCON (R₁) (CH
₂)_p-, -OArO (CH₂)_p-, -OAr (CH₂)_p
-, -O (CH₂CH₂O)_q(CH₂)_p-, -O (C
H₂)_p-, -N (R₁) (CH₂)_p-, -SO₂N
(R₁) (CH₂)_pO (CH₂)_r-, -CON (R₁)
(CH₂)_pO (CH₂)_r-, -OArSO₂N (R₁)
(CHR₁)_pOAr-,-(CH₂)_p(CHOH)
_s(CH₂)_rAnd the like. put it here
Ar represents an aryl group.

As examples of X ⁺ , -N ⁺ (R ₁ ) ₃ , -N ⁺
_{(CH 2 CH 2 OCH 3)} 3, -N + C 4 H 8 O (R 1), - N
_{^{+ (R 1) (R 2}} ) (CH 2 CH 2 OCH 3), - N + C
^{_{5 H 5, -N + (R}} 1) (R 2) (CH 2) p C 6 H 5, -N
⁺ (R ₁ ) (R ₂ ) (R ₂ ) and the like can be mentioned. Here, R ₁ and R ₂ each represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms (which may have a substituent), p, r,
s is 0 to 6, and q is 1 to 20, respectively.

Examples of Z ⁻ include I ⁻ , Cl ⁻ , Br ⁻ , C
_{^{H 3 SO 3 -, CH 3}} -C 6 H 4 -SO 3 - , and the like.

The content of the cationic surfactant according to the present invention is preferably about 1 to 1000 mg / m ² .
5-300 mg / m ² is more preferable.

In the present invention, the inclusion of a small amount of anionic surfactant, nonionic surfactant, or betaine-type surfactant is excluded within a range that does not impair the intended effect of the present invention. Not a thing.

In the present invention, the method for causing the cationic surfactant to be present in at least one of the outermost layer or the porous layer is, for example, a cationic surfactant in the coating solution for forming the outermost layer or the porous layer. A method of adding in advance, a method of forming a surface layer and a porous layer on a support, and then applying a solution containing a cationic surfactant on the outermost surface, or a method of applying a cationic interface to the surface of the coated and dried porous layer. After applying a solution containing an activator, a method of forming the outermost layer can be used, but from the viewpoint of productivity and the effect of the present invention, a coating solution for forming a porous layer and a cationic surface active agent are used. It is preferable to simultaneously apply and dry the coating liquid for forming the outermost layer containing the agent.

Next, a porous layer (also called an ink absorbing layer)
Will be described. The recording paper of the present invention has one or more porous layers, so-called ink absorbing layers.

Generally, the ink absorbing layer is roughly classified into a swelling type and a void type. As the swelling type, a water-soluble binder is used and, for example, gelatin, polyvinyl alcohol, polyvinylpyrrolidone, polyethylene oxide or the like is applied alone or in combination, and this is used as an ink absorbing layer.

As the void type, fine particles and a water-soluble binder are mixed and applied, and those having gloss are particularly preferable. As fine particles, alumina or silica is preferable, and silica having a particle diameter of 0.1 μm or less is particularly preferable. As the water-soluble binder, gelatin, polyvinyl alcohol, polyvinylpyrrolidone, polyethylene oxide and the like are preferably used alone or in combination.

Of the above two types, the one having a high ink absorption speed of the recording paper is suitable for adapting to the continuous high speed printing. From this point, the void type is particularly preferably used in the present invention. it can.

The void type ink absorbing layer will be described in more detail below. The void layer is mainly formed by soft aggregation of the hydrophilic binder and the inorganic fine particles. Conventionally, various methods for forming voids in a film are known,
For example, a method of applying a uniform coating solution containing two or more kinds of polymers on a support, and phase-separating these polymers in a drying process to form voids, solid fine particles and a hydrophilic or hydrophobic resin After coating the coating liquid containing it on a support and drying it, the ink jet recording paper is immersed in water or a liquid containing an appropriate organic solvent to dissolve solid fine particles to form voids, and foaming is performed during film formation. After applying a coating solution containing a compound having properties, a method of foaming this compound in the drying process to form voids in the coating, and a coating solution containing porous solid fine particles and a hydrophilic binder is applied on a support. Then, a method for forming voids in the porous fine particles or between the fine particles, solid fine particles and / or fine particle oil droplets and hydrophilic binder having a volume that is approximately equal to or more than that of the hydrophilic binder. The coating liquid containing coated on a support, and a method of forming an air gap between the solid particles are known. In the present invention, the void layer has an average particle size of 10
It is particularly preferable that it is formed by containing various inorganic solid fine particles of 0 nm or less.

Examples of the inorganic fine particles that can be used in the present invention include light calcium carbonate, heavy calcium carbonate, magnesium carbonate, kaolin, clay, talc,
Calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc hydroxide, zinc sulfide, zinc carbonate, hydrotalcite, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate, synthetic amorphous silica, colloidal silica, alumina, colloidal Examples thereof include white inorganic pigments such as alumina, pseudo-boehmite, aluminum hydroxide, lithopone, zeolite, magnesium hydroxide and the like.

The average particle size of the inorganic fine particles is obtained by observing the particles themselves with an electron microscope, measuring the particle size of 1,000 arbitrary particles, and obtaining the simple average value (number average). Here, the particle size of each particle is represented by the diameter assuming a circle equal to the projected area.

As the inorganic fine particles, solid fine particles selected from silica and alumina or alumina hydrate are preferably used, but silica is more preferable.

As the silica which can be used in the present invention, silica synthesized by a usual wet method, colloidal silica, silica synthesized by a vapor phase method and the like are preferably used, and fine particles particularly preferably used in the present invention. As silica, colloidal silica or fine particle silica synthesized by a vapor phase method is preferable, and silica is particularly preferably silica synthesized by a vapor phase method.

The particle size of the inorganic fine particles is preferably 100 nm or less. For example, in the case of fine particle silica synthesized by the gas phase method, the average particle diameter of primary particles of inorganic fine particles dispersed in the state of primary particles (particle diameter in a dispersion state before coating) is 100 nm or less. It is preferably 4 to 50 nm, more preferably 4 to 20 nm, and most preferably 4 to 20 nm.

The inorganic fine particles are preferably in a state in which the fine particle dispersion liquid before mixing with the cationic polymer is dispersed up to the primary particles.

In the present invention, a water-soluble binder can be used in the ink absorbing layer. Examples of the water-soluble binder that can be used in the present invention include polyvinyl alcohol, gelatin, polyethylene oxide, polyvinylpyrrolidone, polyacrylic acid, polyacrylamide, polyurethane, dextran, dextrin, color genin (κ, ι, λ, etc.), agar. , Pullulan, water-soluble polyvinyl butyral, hydroxyethyl cellulose, carboxymethyl cellulose and the like. It is also possible to use two or more of these water-soluble binders in combination.

The water-soluble binder preferably used in the present invention is polyvinyl alcohol.

The polyvinyl alcohol preferably used in the present invention includes, in addition to ordinary polyvinyl alcohol obtained by hydrolyzing polyvinyl acetate, polyvinyl alcohol having a cation-modified terminal and anion-modified polyvinyl alcohol having an anionic group. The modified polyvinyl alcohol of is also included.

As the polyvinyl alcohol obtained by hydrolyzing vinyl acetate, those having an average degree of polymerization of 1,000 or more are preferably used, and particularly, the average degree of polymerization is 1,500 to
Those of 5,000 are preferably used. Further, the saponification degree is preferably 70 to 100%, and 80 to 99.
5% is particularly preferable.

As the cation-modified polyvinyl alcohol, for example, a primary to tertiary amino group or a quaternary ammonium group as described in JP-A-61-10483 can be used as the main chain or side chain of the polyvinyl alcohol. The polyvinyl alcohol contained therein is obtained by saponifying a copolymer of an ethylenically unsaturated monomer having a cationic group and vinyl acetate.

Examples of the ethylenically unsaturated monomer having a cationic group include trimethyl- (2-acrylamido-2,2-dimethylethyl) ammonium chloride and trimethyl- (3-acrylamido-3,3-dimethylpropyl). ) Ammonium chloride, N-vinylimidazole, N-vinyl-2-methylimidazole, N
-(3-dimethylaminopropyl) methacrylamide,
Hydroxylethyltrimethylammonium chloride, trimethyl- (2-methacrylamidopropyl) ammonium chloride, N- (1,1-dimethyl-3-)
Examples include dimethylaminopropyl) acrylamide.

The ratio of the cation-modified group-containing monomer of the cation-modified polyvinyl alcohol is 0.1 to 10 mol%, preferably 0.2 to 5 mol%, based on vinyl acetate.

The anion-modified polyvinyl alcohol is described in, for example, polyvinyl alcohol having an anionic group as described in JP-A-1-206088 and JP-A-61-237681 and 63-307979. Such a copolymer of vinyl alcohol and a vinyl compound having a water-soluble group, and JP-A-7-285.
The modified polyvinyl alcohol which has a water-soluble group as described in No. 265 is mentioned.

As the nonion-modified polyvinyl alcohol, for example, a polyvinyl alcohol derivative obtained by adding a polyalkylene oxide group to a part of vinyl alcohol as described in JP-A-7-9758, JP-A-8-25795. And a block copolymer of a vinyl compound having a hydrophobic group and vinyl alcohol as described in 1. Polyvinyl alcohol can be used in combination of two or more types such as different degree of polymerization or modification.

The addition amount of the inorganic fine particles used in the ink absorbing layer depends on the required ink absorbing capacity, the porosity of the void layer,
Generally depends on the type of inorganic pigment and the type of water-soluble binder, but generally 5 to 3 per 1 m ^{2 of} recording paper.
It is 0 g, preferably 10 to 25 g.

The ratio of the inorganic fine particles used in the ink absorbing layer to the water-soluble binder is usually 2: 1 by mass.
It is 20: 1, and particularly preferably 3: 1 to 10: 1.

In the ink jet recording paper of the present invention, a cationic polymer is preferably used for the purpose of preventing image bleeding due to storage after recording.

Examples of the cationic polymer include polyethyleneimine, polyallylamine, polyvinylamine,
Dicyandiamide polyalkylene polyamine condensate, polyalkylene polyamine dicyandiamide ammonium salt condensate, dicyandiamide formalin condensate, epichlorohydrin / dialkylamine addition polymer, diallyldimethylammonium chloride polymer, diallyldimethylammonium chloride / SO ₂ copolymer, polyvinylimidazole, Vinylpyrrolidone / vinylimidazole copolymer, polyvinylpyridine, polyamidine, chitosan, cationized starch, vinylbenzyltrimethylammonium chloride polymer, (2-methacryloyloxyethyl) trimethylammonium chloride polymer,
Examples thereof include dimethylaminoethyl methacrylate polymer.

The Chemical Industry Bulletin August 15, 1998,
Examples include the cationic polymer described on 25th, and the polymer dye fixing agent described in "Introduction to Polymeric Drugs" issued by Sanyo Chemical Industries, Ltd.

The amount of the cationic water-soluble polymer added is
Usually 0.1 to 10 per 1 m ^{2 of} inkjet recording paper
g, preferably in the range of 0.2-5 g.

In the void layer, the total amount of voids (void volume)
Is preferably 20 ml or more per 1 m ² of recording paper. If the void volume is less than 20 ml / m ^{2 and} the ink amount during printing is small, the ink absorbability is good, but if the ink amount is large, the ink is not completely absorbed, and the image quality may deteriorate. Problems such as delayed drying tend to occur.

In the void layer having an ink holding ability, the void volume with respect to the solid content volume is called the porosity. In the present invention, it is preferable that the porosity is 50% or more because the voids can be efficiently formed without unnecessarily increasing the film thickness.

As the other type of void type, a polyurethane resin emulsion, a water-soluble epoxy compound and /
Or in combination with acetoacetylated polyvinyl alcohol,
Further, the ink absorbing layer may be formed by using a coating liquid in which epichlorohydrin polyamide resin is used in combination. The polyurethane resin emulsion in this case is preferably a polyurethane resin emulsion having a polycarbonate chain, a polycarbonate chain and a polyester chain and having a particle diameter of 3.0 μm, and the polyurethane resin of the polyurethane resin emulsion is a polycarbonate polyol, a polyol having a polycarbonate polyol and a polyester polyol. Polyurethane resin obtained by reacting with an aliphatic isocyanate compound has a sulfonic acid group in the molecule, and further has an epichlorohydrin polyamide resin and a water-soluble epoxy compound and / or acetoacetylated vinyl alcohol. preferable. It is presumed that in the ink absorbing layer using the polyurethane resin, weak cations and anions are formed, and along with this, voids having an ink solvent absorbing ability are formed and an image can be formed.

In the present invention, it is preferable to use a curing agent. The curing agent can be added at any time during the production of the inkjet recording paper, and for example, may be added to the coating liquid for forming the ink absorption layer.

In the present invention, the method of supplying the curing agent for the water-soluble binder after the formation of the ink absorbing layer may be used alone, but the above-mentioned curing agent is preferably used in the coating liquid for forming the ink absorbing layer. It is to be used in combination with the method of adding to.

The curing agent that can be used in the present invention is not particularly limited as long as it causes a curing reaction with a water-soluble binder, but boric acid and salts thereof are preferable, but other known ones are used. In general, a compound having a group capable of reacting with a water-soluble binder or a compound that promotes a reaction between different groups of the water-soluble binder, and is appropriately selected and used according to the type of the water-soluble binder. To be Specific examples of the curing agent include, for example,
Epoxy curing agent (diglycidyl ethyl ether, ethylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-diglycidyl cyclohexane, N, N-diglycidyl-4-glycidyloxyaniline, sorbitol polyglycidyl ether , Glycerol polyglycidyl ether, etc.), aldehyde curing agents (formaldehyde, glyoxal, etc.), active halogen curing agents (2,4-dichloro-4-)
Hydroxy-1,3,5, -s-triazine etc.), active vinyl compounds (1,3,5-trisacryloyl-hexahydro-s-triazine, bisvinylsulfonylmethyl ether etc.), aluminum alum and the like.

Boric acid or a salt thereof means an oxygen acid having a boron atom as a central atom and a salt thereof, and specifically, orthoboric acid, diboric acid, metaboric acid, tetraboric acid,
Pentaboric acid and octaboric acid and their salts are mentioned.

The boric acid having a boron atom and its salt as a curing agent may be used in the form of a single aqueous solution or as a mixture of two or more kinds. Particularly preferred is a mixed aqueous solution of boric acid and borax.

The aqueous solutions of boric acid and borax can be added only in relatively dilute aqueous solutions, but by mixing them, a concentrated aqueous solution can be obtained and the coating solution can be concentrated. . Further, there is an advantage that the pH of the aqueous solution to be added can be controlled relatively freely. The total amount of the curing agent used is the above water-soluble binder 1
1 to 600 mg per g is preferred.

Various additives other than those described above can be used in the ink absorbing layer of the ink jet recording paper of the present invention and other layers provided as necessary. For example, polystyrene, polyacrylic acid esters, polymethacrylic acid esters, polyacrylamides, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, or copolymers thereof, urea resin, or organic latex fine particles such as melamine resin , Anionic, cationic, nonionic and amphoteric surfactants, JP-A-57-74
193, 57-87988 and 62-2614.
UV absorbers described in JP-A-76-74192.
No. 57-87989, No. 60-72785, No. 61-146591, No. 1-95091 and No. 3-13376, and anti-fading agents, JP-A-59-42993, 59-52689, 62
-280069, 61-242871, JP-A-4-219266 and the like, fluorescent whitening agents, sulfuric acid, phosphoric acid, citric acid, sodium hydroxide, potassium hydroxide, pH adjusting agents such as potassium carbonate , Antifoam, antiseptic,
Various known additives such as a thickener, an antistatic agent and a matting agent may be contained.

The ink absorbing layer may be composed of two or more layers. In this case, the structures of these ink absorbing layers may be the same or different from each other.

The method of applying various kinds of ink-absorbing layers, such as the surface layer and the porous layer constituting the recording paper of the present invention, and the subbing layer, which are appropriately provided as necessary, to the support is appropriately selected from known methods. You can do it. A preferred method is obtained by applying a coating solution forming each layer on a support and drying.

One of the preferable coating methods in the present invention is a method of forming a recording layer by coating the surface layer after drying all of one or more porous layers on a support, and another preferable method. The coating method is a method in which one or more porous layers and a surface layer are coated on a support at the same time and dried, and by using any of the above methods, a crack failure does not occur and a stable coating is achieved. A surface layer can be formed, which is preferable.

As the coating method, for example, roll coating method, rod bar coating method, air knife coating method, spray coating method, curtain coating method, or extrusion coating using a hopper described in US Pat. No. 2,681,294. The method is preferably used.

In image recording using the ink jet recording paper of the present invention, a recording method using water-based ink is preferable.

The water-based ink in the present invention means a recording liquid containing the following colorant, liquid medium and other additives.

As the colorant which can be used in the present invention, use is made of a water-soluble dye or a water-dispersible pigment such as a direct dye, an acid dye, a basic dye, a reactive dye, a food dye, etc., which are known in ink jet. You can Among them, a particularly preferable colorant is an ink using a phthalocyanine dye as a cyan dye. Phthalocyanine dyes are particularly widely known and used among cyan dyes.

As the solvent for the water-based ink, water and various water-soluble organic solvents such as alcohols such as methyl alcohol, i-propyl alcohol, butyl alcohol, t-butyl alcohol, i-butyl alcohol; dimethylformamide, dimethyl are used. Amides such as acetamide;
Ketones or ketone alcohols such as acetone and diacetone alcohol; ethers such as tetrahydrofuran and dioxane; polyalkylene glycols such as polyethylene glycol and polypropylene glycol; ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1, 2, 6-hexanetriol, thiodiglycol, hexylene glycol,
Polyhydric alcohols such as diethylene glycol, glycerin, triethanolamine; ethylene glycol methyl ether, diethylene glycol methyl (or ethyl)
Examples thereof include lower alkyl ethers of polyhydric alcohols such as ether and triethylene glycol monobutyl ether.

Of these water-soluble organic solvents, polyhydric alcohols such as diethylene glycol, triethanolamine and glycerin, and lower alkyl ethers of triethylene glycol monobutyl ether are preferable.

As other additives for the water-based ink, for example, a pH adjusting agent, a sequestering agent, an antifungal agent, a viscosity adjusting agent,
Surface tension adjusting agents, wetting agents, surfactants, rust preventives and the like can be mentioned.

In order to improve the wettability with respect to the recording paper, the aqueous ink liquid is 25-60 mN / at 20 ° C.
It is preferable to have a surface tension in the range of m, preferably 30 to 50 mN / m.

The printer that can be used in the present invention is not particularly limited as long as it has a recording paper accommodating section, a conveying section, an ink cartridge and an ink jet print head, like a commercially available printer. At least a roll-shaped recording paper storage unit, transport unit,
It is preferable that the printer set includes an inkjet print head, a cutting unit, and if necessary, a heating unit, a pressure unit, and a recording print storage unit. The inkjet print head used may be an on-demand type or a continuous type. In addition, as a discharge method, an electro-mechanical conversion method (for example, a single cavity type, a double cavity type, a bender type, a piston type, a shear mode type, a shared wall type, etc.), an electric-heat conversion method (for example, a thermal type Examples thereof include an inkjet type, a bubble jet (R) type, an electrostatic suction type (for example, an electric field control type, a slit jet type, etc.), and a discharge type (for example, a spark jet type). The electro-mechanical conversion method is preferred, but any ejection method may be used.

[0122]

The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.

<< Preparation of Inkjet Recording Paper >> Recording papers 1 to 12 were prepared according to the following procedure.

[Preparation of Recording Paper 1] A paper support (thickness: 230 μm) coated on both sides with polyethylene was used, and a liquid temperature of 45
The following porous layer coating solution 1 at 0 ° C. was applied using an extrusion type coater, dried and then stored in a thermostat at 40 ° C. and 80% RH for 12 hours to obtain a recording paper 1. The dry film thickness was 35 μm. The amount of silica fine particles applied to the recording paper 1 was 15 g / m ² , and the amount of the cationic polymer (C-
The coating amount of 1) was 2.2 g / m ² , and the coating amount of polyvinyl alcohol was 2.3 g / m ² .

(Preparation of Porous Layer Coating Solution 1) Silica
The cationic polymer dispersion liquid 1 was heated to 45 ° C., a 10% aqueous solution of polyvinyl alcohol (Kuraray, PVA203) and other polyvinyl alcohol (Kuraray, PVA2) were used.
The 6% aqueous solution of 45) was added to each after raising the temperature to 45 ° C. Finally, pure water at 45 ° C. was added so as to have a constant volume to obtain a semi-transparent porous layer coating liquid 1.

<Preparation of Silica-Cationic Polymer Dispersion 1> 15% aqueous solution of cationic polymer (C-1) 10
To 0 g, 500% of a 20% aqueous dispersion of fine particle silica (QS-20 manufactured by Tokuyama Corp.) having an average primary particle diameter of 12 nm.
g, then 3.0 g of boric acid and 0.7 g of borax were added and dispersed by a high-speed homogenizer to obtain a white-white silica-cationic polymer dispersion liquid 1.

[0127]

[Chemical 7]

[Preparation of Recording Sheet 2] On Recording Sheet 1
And 0.5 g of the following organic fine particle emulsion (L-1)
/ M ², Fine particle silica (QS-20 manufactured by Tokuyama)
0.25g / m², Acrylic emulsion (Tg =-
30 ° C., average particle size 30 nm) is 0.05 g / m²From
The surface layer coating liquid 1 is formed by using an extrusion type coater.
After coating and drying, place it in a constant temperature bath at 40 ° C and 80% RH.
It was stored for 12 hours to obtain a recording sheet 2.

(Preparation of Organic Fine Particle Emulsion (L-1)) Emulsion polymerization was carried out by a known method using a monomer of n-butyl methacrylate: styrene: 2-hydroxyethyl methacrylate = 10: 65: 25 (mass ratio). , An organic fine particle emulsion (L-1) was prepared. The surfactant used in the above-mentioned preparation was Emulgen 320P (polyoxyethylene stearyl ether manufactured by Kao), and was added in an amount of 3 mass% as a solid content based on the total amount of monomers. The organic fine particle emulsion (L-
The average particle diameter of the organic fine particles contained in 1) was 50 nm as measured by a laser scattering method, and the glass transition temperature (Tg) calculated from the Tg of each constituent monomer by the above-mentioned method was 72 ° C. Met.

[Preparation of Recording Paper 3] In preparation of the above recording paper 2, the organic fine particle emulsion (L-1) of the surface coating liquid 1 was replaced with the following organic fine particle emulsion (L-
Recording paper 3 was prepared in the same manner except that the surface layer coating liquid 2 changed to 2) was used.

(Preparation of Organic Fine Particle Emulsion (L-2)) Emulsion polymerization was performed according to a known method using a monomer of t-butyl methacrylate: styrene: 2-hydroxyethyl methacrylate = 30: 55: 15 (mass ratio). , An organic fine particle emulsion (L-2) was prepared. The surfactant used for the above-mentioned preparation was Emulgen 220 (manufactured by Kao), and was added in a solid content of 5% by mass with respect to the total amount of the monomers. The average particle size of the organic fine particles contained in the organic fine particle emulsion (L-2) prepared as described above was 40 nm as measured by a laser scattering method,
The glass transition temperature (Tg) calculated from the Tg of each constituent monomer by the above-mentioned method was 103 ° C.

[Preparation of Recording Paper 4] In preparation of the above-mentioned recording paper 2, the surface layer coating solution 1 was mixed with the surfactant S-1 (sodium dodecyl sulfonate anionic surfactant).
Was prepared in the same manner as above, except that an amount of 25 mg / m ² was added.

[Preparation of Recording Paper 5] In preparation of Recording Paper 2, the surface layer coating liquid 1 was supplemented with 25 mg / m ² of the surfactant S-2 (polyoxyethylene nonylphenyl ether nonionic surfactant). A recording paper 5 was prepared in the same manner except that the following amount was added.

[Preparation of Recording Papers 6 and 7] In the preparation of the recording papers 4 and 5, the porous layer coating liquid 1 and the surface layer coating liquid containing each surfactant were mixed with an extrusion type coater 2 Recording papers 6 and 7 were prepared in the same manner except that the layers were simultaneously applied.

[Preparation of Recording Paper 8] In preparation of the recording paper 2, the surface layer coating liquid 1 was mixed with the surfactant S-3 (C ₈
The _{F 1 7 SO 2 NH (CH} 2) 3 · Br cationic surfactant), except for adding an amount of a 25 mg / m ² in the same manner to produce a recording sheet 8.

[Preparation of Recording Paper 9] In preparation of the recording paper 2, the surface layer coating liquid 1 contains the surfactant S-4 (lauryltrimethylammonium chloride cationic surfactant) in an amount of 25 mg / m ² . A recording paper 9 was prepared in the same manner except that was added.

[Preparation of Recording Paper 10] In preparation of the recording paper 3, the surface layer coating solution 2 contains 25 mg / m ² of the surfactant S-4 (lauryltrimethylammonium chloride cationic surfactant). A recording paper 10 was produced in the same manner except that was added.

[Preparation of Recording Papers 11 and 12] In preparation of the above-mentioned recording papers 9 and 10, the porous layer coating liquid 1 and the surface layer coating liquid 2 containing each surfactant were prepared by using an extrusion type coater. Recording sheets 11 and 12 were produced in the same manner except that two layers were simultaneously coated.

The "separate layer coating" described in the coating method column in Table 1 represents a method (recording papers 2 to 5 and 8 to 10) in which the porous layer and the surface layer are individually applied, and "simultaneous coating""Coating" is a method of simultaneously coating the porous layer and the surface layer (recording paper 6, 7, 1).
1, 12).

[Electron Microscopic Observation of Surface and Cross Section of Recording Paper] (Observation of Surface and Cross Section of Each Recording Material After Treatment A) The surface and cross section of the recording paper 1 to 12 subjected to the following treatment A by an electron microscope. When observed, recording paper 2-12
It was observed that the organic fine particles in the surface layer were melted or swollen and thus fused with each other.

[0141] <Process A> diethylene glycol monobutyl ether [SP value 19.437 (MPa) ^1/2, boiling point 230 ° C.] 20% aqueous solution of was uniformly sprayed on the surface of the recording sheet 12. The coating amount was 20 ml / m ² . Next, this portion was dried in an environment of 23 ° C. and 55% RH for 1 hour.

<< Evaluation of Crack Resistance >> The recording surface side surface of 10 × 10 cm ² of each recording sheet prepared above was observed with a magnifying glass and the number of cracks having a length of 0.2 mm or more was counted. The resistance to cracking was evaluated according to the standard of 1. and the obtained results are shown in Table 1.

⊚: The number of cracks is 3 or less ○: The number of cracks is 4 to 10 Δ: The number of cracks is 11 to 20 ×: The number of cracks is 21 or more In the evaluation,
If ⊚ or ○, it was judged to be within the practically acceptable range.

<< Evaluation of Inkjet Image Printing and Discoloration Resistance >> (Preparation of Ink Liquid) A cyan ink liquid having the following composition was prepared.

Water 68.5 parts Diethylene glycol monobutyl ether 12 parts Diethylene glycol 10 parts Glycerin 8 parts C.I. I. Direct Blue 86 1 part Surfactant (Surfynol 465, manufactured by Nisshin Chemical Industry Co., Ltd.) 0.5 part (Evaluation of fading resistance 1)
After storing for 1 week in an atmosphere of 3 ° C and 55% RH, 23
An image was printed according to the following method in an atmosphere of 55 ° C. and 55% RH.

Ink jet printer M
Mounted on J-800C (manufactured by Seiko Epson Corporation),
A solid cyan image was printed on each recording sheet that had been subjected to the above-mentioned storage processing. The ink discharge rate was 12 ml / m ² . After leaving this image in the environment of 23 ° C and 55% RH for 24 hours, each solid print image part is attached to the window inside the office room and left for 6 months in an environment where the outside air is exposed but direct sunlight does not hit. Then, the discoloration resistance 1 was evaluated according to the following method.

The reflection density of each printed portion of the sample before standing and the sample left for 6 months was measured with red monochromatic light, and the residual density ratio was calculated according to the following formula. This was evaluated for resistance to fading under normal humidity storage. The scale was 1.

Percentage of remaining density 1 = (printing density after leaving for 6 months / printing density before leaving) × 100 (%) (Evaluation of fading resistance 2)
After storing for 1 week in an atmosphere of 3 ° C. and 20% RH,
An image was printed according to the following method in an atmosphere of ° C and 20% RH.

Ink jet printer M
Mounted on J-800C (manufactured by Seiko Epson Corporation),
A solid cyan image was printed on each recording sheet that had been subjected to the above-mentioned storage processing. The ink discharge rate was 12 ml / m ² . After leaving this image for 24 hours in an environment of 23 ° C. and 20% RH, stick each solid print image part to the window inside the office room and leave it for 6 months in an environment where the outside air is exposed but direct sunlight does not hit. Then, the fading resistance 2 was evaluated according to the following method.

The reflection density of each printed portion of the sample before standing and the sample left for 6 months was measured by red monochromatic light, and the residual density ratio was calculated according to the following formula. Was used as a scale.

Concentration residual rate 2 = (printing density after leaving for 6 months / printing density before leaving) × 100 (%) Table 1 shows the results obtained as described above.

[0152]

[Table 1]

As is clear from Table 1, the comparative sample in which the organic fine particles were added to the surface layer but no cationic surfactant was used showed the resistance to fading after storage under normal humidity. The effect of improving discoloration after storage at low humidity is reduced, and in particular, the sample formed by the simultaneous coating method of the surface layer and the porous layer,
There are many cracks on the surface layer, and the effect of improving discoloration is reduced. On the other hand, the recording paper of the present invention containing the cationic surfactant in the surface layer together with the organic fine particles A or the organic fine particles B has a smaller number of cracks in the formed coating film as compared with the comparative example. Excellent resistance to discoloration after storage under humid conditions, and even after storage under low humidity
It can be seen that the discoloration prevention effect is favorably maintained.

[0154]

INDUSTRIAL APPLICABILITY According to the present invention, an ink jet recording paper which reduces the coating failure (cracking failure) of the surface layer which exhibits the fading prevention effect and is excellent in the fading resistance against harmful gas even when stored in a low humidity environment. And a manufacturing method thereof.

Continued front page    F-term (reference) 2C056 EA13 FC06                 2H086 BA14 BA15 BA33 BA41 BA45                 4D075 AE16 AE23 BB24Y BB24Z                       CA03 CA32 CA35 CA38 CA44                       CA48 CB04 DA04 DB18 DB36                       DC27 EA06 EA13 EB07 EB08                       EB10 EB12 EB13 EB14 EB15                       EB18 EB19 EB20 EB22 EB35                       EB37 EB38 EB39 EB53 EB54                       EB56 EB57 EC03 EC07 EC30                       EC52 EC53 EC54

Claims (4)

[Claims] 1. A support has a surface layer containing organic fine particles A or organic fine particles B defined below and one or more porous layers, and at least one of the surface layer or the porous layer. An inkjet recording paper, wherein the layer contains a cationic surfactant. Organic fine particles A: SP value is 18.414 to 30.69 (M
Pa) ^1/2 and water-insoluble organic fine particles that dissolve or swell in a water-soluble organic solvent having a boiling point of 120 ° C. or higher, have a glass transition temperature (Tg) of 70 ° C. or higher, and have an average particle size of 100 nm or less. Organic fine particles. Organic fine particles B: having a polymer containing 5% by mass or more of a repeating unit represented by the following general formula (1) as a copolymerization component, having a glass transition temperature (Tg) of 70 ° C. or higher, and an average particle diameter of 100 nm. The following organic particles. [Chemical 1] [In the formula, X represents -O- or -N (R ₂ )-, R ₁ represents a hydrogen atom or a methyl group, R ₂ represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and X represents Is -O-, J is an alkylene group having 2 to 8 carbon atoms and optionally having an ether structure or a thioether structure,
Y represents a hydroxyl group, an alkoxyl group or a carbamoyl group, and when X is —N (R ₂ ) —, J may have a single bond or an ether structure or a thioether structure having 2 to 8 carbon atoms. A good alkylene group, Y
Represents a hydrogen atom, a hydroxyl group, an amino group, an alkoxyl group or a carbamoyl group. ] 2. An ink jet recording paper having a surface layer containing the organic fine particles A or the organic fine particles B defined above on a support and one or more porous layers, the surface layer being emulsion-polymerized. An inkjet recording sheet containing the organic fine particles A or the organic fine particles B defined above and a cationic surfactant. 3. The method for producing an inkjet recording paper according to claim 1, wherein one or more porous layers are applied on a support and dried, and then the surface layer is applied.
A method for producing an ink jet recording paper, which comprises drying and producing. 4. A method for producing an ink jet recording paper according to claim 1, wherein the support is coated with one or more porous layers and a surface layer at the same time and dried. And a method for manufacturing an inkjet recording paper.