JP2001341416A - Coating liquid for ink jet recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording medium having excellent light resistance, excellent ink acceptance, color developability and transparency of a dye ink or a pigment ink and an improved ink absorbing speed, a (matt) ink jet recording medium having a reduced surface glossiness and a coating liquid capable of forming an ink acceptive layer suitable for the recording medium. SOLUTION: This coating liquid for the ink jet recording medium comprises a cellulose having a mean degree of polymerization(DP) of 100 or less, a fraction of a cellulose I type crystal component of 0.1 or less, a fraction of a cellulose II type crystal component of 0.4 or less and a mean particle size of the cellulose particles for constituting of 5 μm or less. The ink jet recording medium is manufactured by using the coating liquid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating liquid for forming an ink jet recording medium and an ink jet recording medium obtained by using the coating liquid. More specifically, it has excellent light fastness, is excellent in acceptability of dye or pigment ink, excellent in color development, transparency, and has improved ink absorption speed. The present invention relates to a coating liquid capable of forming an ink receiving layer suitable for a (matte) ink jet recording medium, and an ink jet recording medium obtained by using the coating liquid.

[0002]

2. Description of the Related Art Conventionally, various recording methods such as a wire dot recording method, a thermosensitive coloring recording method, a thermosensitive thermal transfer recording method, a thermosensitive sublimation transfer recording method, an electrophotographic recording method and an ink jet recording method have been used. There is. Among them, the ink jet system has the features that plain paper can be used as a recording medium, the printing cost is low, the apparatus is compact, there is no noise, high-speed recording, and color printing is easy.

[0003] Printed out by these ink jet recording methods are large posters, displays,
In recent years, the demand for flyer and other media having design properties has been rapidly increasing. Generally, water-based inks are used in these printers. The aqueous ink is classified into a dye ink and a pigment ink, and the dye ink is mainly used from the viewpoint of sharpness. However, in recent years, it has been pointed out that a dye ink cannot provide sufficient weather resistance because it has been used as a large-sized poster for outdoor display.

[0004] On the other hand, the pigment ink has the feature of being excellent in weather resistance, but has the disadvantage that a crack occurs in the image and a clear image cannot be obtained (poor in acceptability).
As a method for improving the cracks in this image, for example, a method using nitric esters of carboxyalkylcellulose has been proposed, but this method is not necessarily sufficient for recent demands for high image quality (Japanese Unexamined Patent Publication No. 244
224). Further, when a transparent film is used as a support, the conventional porous ink receiving layer has a disadvantage that the light transmittance is low because of the low light transmittance.

[0005] In particular, recently, due to the increase in the ink discharge amount accompanying the increase in speed and resolution of a color ink jet printer, a recording medium having good ink absorption, that is, a high ink absorption speed and a large ink absorption capacity is required. It has become. As a recording medium having an improved ink absorption rate, a recording medium containing fine particles and / or microfibrous cellulose in an ink receiving layer (Japanese Patent Application Laid-Open No. 9-164760)
However, there is a problem that the transparency is inferior due to the high whiteness of cellulose itself and the image lacks sharpness.

[0006]

DISCLOSURE OF THE INVENTION The present invention has excellent light fastness, acceptability of dye ink and pigment ink, coloring property,
An object of the present invention is to provide an ink jet recording medium having excellent transparency and an excellent ink absorption rate, and a coating liquid which satisfies the above and enables an ink jet recording medium having a matte surface.

[0007]

Means for Solving the Problems The present inventors have proposed PCT /
In JP 98/05462, a transparent to translucent cellulose dispersion is obtained. The present inventors have studied the application of the cellulose dispersion as a coating liquid for an ink jet recording medium. As a result, the ink jet recording medium using the coating liquid did not lose light fastness, and thus, a dye ink or a pigment ink was used. The present invention has been found to be excellent in the receptivity, color developing property and transparency of the ink, and also improved in the ink absorption rate as compared with the conventional ink jet recording medium. Was completed.

That is, the present invention provides [1] an average degree of polymerization (D
P) is 100 or less, the fraction of the cellulose type I crystal component is 0.1 or less, the fraction of the cellulose type II crystal component is 0.4 or less, and the average particle diameter of the constituting cellulose particles is 5 or less.
[2] A coating liquid for an inkjet recording medium containing 0.001 to 5% by weight of cellulose having a particle size of not more than μm, wherein the coating solution contains fine particles other than cellulose having an average particle size of not more than 300 nm. [1] The coating liquid for an ink jet recording medium according to [1] or [2], wherein the coating liquid for an ink jet recording medium according to [1] contains [3] a cation-modified polymer in an amount of 0.001 to 15% by weight. [4] An ink jet recording medium having an ink receiving layer on at least one surface of a support, wherein the ink receiving layer has an average degree of polymerization (DP) of 100.
Below, the fraction of the cellulose type I crystal component is 0.1 or less,
An inkjet recording medium comprising: 0.01% by weight or more of cellulose having a cellulose II type crystal component fraction of 0.4 or less, [5] 1 in the ink receiving layer.
[4] The ink-jet recording medium according to [4], wherein the ink-receiving layer contains fine particles other than cellulose having an average particle diameter of not more than 00 nm. The inkjet recording medium according to [4] or [5],
[7] The degree of nitrate group substitution per anhydroglucose unit between the support and the ink receiving layer is 0.2 to 0.2.
A lower layer containing 3-80% by weight of a carboxyalkyl cellulose nitrate having a degree of carboxyalkyl ether group substitution of 0.05 to 2.8 and 20 to 97% by weight of an aqueous polymer. The inkjet recording medium according to [4], [5] or [6], wherein the aqueous polymer is a cation-modified polymer. ,.

Hereinafter, the present invention will be described in detail. The coating liquid of the present invention is used for forming an ink receiving layer of an ink jet recording medium. The coating liquid has an average degree of polymerization (D
P) is 100 or less, the fraction of the cellulose type I crystal component is 0.1 or less, the fraction of the cellulose type II crystal component is 0.4 or less, and the average particle size of the constituting cellulose particles is 5
It is necessary to contain 0.001 to 5% by weight of cellulose having a size of μm or less.

[0010] The cellulose used in the present invention preferably has a transparency comparable to that of a water-soluble polymer aqueous solution, and is in a state where cellulose is highly dispersed in a dispersion medium. Thus, even when a coating film is formed, the film exhibits transparency and can maintain appropriate strength and flexibility. The dispersion of the cellulose dispersion is preferably water, but may contain a water-soluble organic solvent such as alcohols. Further, in this raw material cellulose dispersion, in order to enhance the stability of the dispersion, a water-soluble polymer, a nonionic surfactant, a cationic surfactant, an anionic surfactant, an amphoteric surfactant, and further, Organic compounds and inorganic salts that can be dissolved in water such as urea or a mixed solution of water / organic solvent may be contained.

In the present invention, the cellulose has an average degree of polymerization (DP) of 100 or less, preferably 50 or less. D
If P exceeds 100, it is difficult to obtain a cellulose dispersion highly dispersed in a dispersion medium. The cellulose of the present invention is a dispersion of cellulose insoluble in water, and has a DP of 20.
That is all. The cellulose of the present invention are cellulose I type crystal component amount (chi _I) is 0.1 or less, preferably 0.
06 and a low crystallinity of the cellulose II type crystal component amount (成分_II ) of 0.4 or less, preferably 0.3 or less. Fraction of cellulose crystalline component of the present invention can be up to (χc, i.e. the sum of the chi _I and chi _II) is a value close to almost zero. chi cellulose _I exceeds 0.1 or the chi _II exceeds 0.4, the high whiteness, because interaction force between the cellulose particles in the dispersion medium is lowered, Ya transparency when forming a film Extremely low strength and flexibility. Further, it is inferior in terms of ink absorption and coloring.

In the cellulose dispersion of the present invention, the average particle diameter of the constituent cellulose in the cellulose dispersion as a raw material is 5 μm or less, preferably 3.5 μm, as measured by a measuring method described later.
The thickness is more preferably 1 μm or less. The lower limit of the average particle size can be set to about 0.02 μm, which is close to the lower limit of detection of the measurement method defined by the present invention. If it exceeds 5 μm, the fixability to the support decreases, and the transparency of the coating film deteriorates.
The resolution of the printed matter is reduced.

The average particle diameter of the cellulose constituting the present invention is defined as the average particle diameter of cellulose which is isotropically associated and dispersed in a dispersion medium in a cellulose dispersion as a raw material. According to the method for measuring the average particle diameter of the invention, it means the size of “spread (diameter)” of cellulose when dispersed as finely as possible by means such as ultrasonic waves. The necessity of such handling depends on the form in which the cellulose of the present invention is present in the dispersion medium, and the presence of cellulose microparticles such as existing microcrystalline cellulose (MCC) and microfibrillated cellulose (MFC) in the suspension. It shows that it is clearly different from the form.

The cellulose of the present invention, in the state of a cellulose dispersion as a raw material, is different from existing cellulose additives, such as MCC, in such a high degree that the particles cannot be clearly confirmed by observation with an optical microscope. It has a structure dispersed in a medium, and has a diameter of about 0.01 μm (10 n
m) has a structure in which the spherical particles are connected in a bead shape.
Cellulose of the present invention, in the state of a cellulose dispersion, such a fine structure is innumerably entangled to form a network-like structure, associated with a certain finite size and exists as a microgel. It is estimated that there is.

Such a cellulose of the present invention has a very high associative property in the state of a cellulose dispersion, and the extent of “spreading” changes depending on the degree of cleavage of the associative state. For example, the average particle diameter of the dispersion of the present invention is a sample that is left standing for a long time, whereas it may be measured to about several hundred μm when measured without performing ultrasonic treatment, When the same dispersion is measured by the average particle diameter measuring method specified in the present invention, the average particle diameter is measured to be 5 μm or less. This is evidence that cellulose having a small particle size is extremely highly associated in the composition of the present invention. In the dispersion of MCC or microfibrillated cellulose (MFC), the above-mentioned extreme change in the average particle diameter is not usually observed.

The method for analyzing cellulose is described below. Average polymerization degree of the cellulose (DP), the fraction of cellulose I and cellulose II type crystal component (chi _I and chi _II), average particle diameter of the cellulose dispersion raw material for producing a coating liquid, the following Calculated by the procedure. The fraction of cellulose type I crystal component (χ _I ) is determined by drying a cellulose dispersion raw material, drying a dried cellulose sample, pulverizing it into a powder, forming a tablet,
In the wide-angle X-ray diffraction diagram obtained by the reflection method with the source CuKα,
From the absolute peak intensity h _{0 at} 2θ = 15.0 ° attributed to the (110) plane peak of the cellulose type I crystal and the peak intensity h ₁ from the baseline at this plane interval, it is determined by the following equation (1). Values were used. Similarly, the fraction (χ _II ) of the cellulose type II crystal component can be determined by pulverizing a dried cellulose sample into a powder and forming it into a tablet, using a radiation source CuK
In the wide-angle X-ray diffraction pattern obtained by the reflection method at α, cellulose
2θ = 1 attributed to the (110) plane peak of type II crystal
From the absolute peak intensity h ₀ * at 2.6 ° and the peak intensity h ₁ * from the baseline at this plane interval, a value determined by the following equation (2) was used. χ _I = h ₁ / h ₀ (1) χ _II = h ₁ * / h ₀ * (2)

[0017] FIG. 1 shows a schematic diagram for obtaining the chi _I and chi _II. The cellulose sample was a dried cellulose sample obtained by drying by a method such as a reduced pressure drying method. The average degree of polymerization (DP) specified in the present invention is determined by measuring the specific viscosity of a dilute cellulose solution obtained by dissolving the above-described dried cellulose sample in cadoxene using an Ubbelohde viscometer (25 ° C.), and determining the intrinsic viscosity [η] thereof. The value calculated by the following viscosity formula (3) and conversion formula (4) was adopted. [η] = 3.85 × 10 ⁻² × MW ^0.76 (3) DP = MW / 162 (4)

In the present invention, the average particle size of the cellulose is determined by measuring the particle size distribution of the cellulose dispersion as a raw material with a laser diffraction type particle size distribution analyzer (manufactured by HORIBA, Ltd., laser diffraction / scattering type particle size distribution analyzer LA-) 920; the lower limit detection value is an average particle diameter obtained by measurement at 0.02 μm). In order to measure the particle diameter in a state where the association between the particles in the dispersion medium was cut as much as possible, a sample was prepared in the following step. After diluting the cellulose dispersion raw material with water so that the cellulose concentration becomes about 0.5% by weight, the rotation speed is set to 150%.
Mixing treatment is performed for 10 minutes with a blender having a capacity of 00 rpm or more to form a uniform suspension. Next, the dispersion sample obtained by subjecting this suspension to ultrasonic treatment for 30 minutes was supplied to a cell of a particle size distribution measuring device, and subjected to ultrasonic treatment again (3 minutes), and then the particle size distribution was measured.

The coating liquid for an inkjet recording medium containing cellulose of the present invention comprises cellulose and a dispersion medium. If necessary, various kinds of fine particles other than cellulose, a water-soluble polymer, and an additive such as a cation-modified polymer can be appropriately added to enhance the ink fixing property. The content of cellulose in the coating liquid is 0.001 to 5% by weight, preferably 0.05% by weight, based on the total weight of the coating liquid.
5 to 3% by weight. Within this range, a coating liquid having uniform properties can be suitably provided. Since the viscosity and the like greatly depend on the contents of the constituent components, an appropriate composition may be determined according to the purpose of use or the system. If it exceeds 5% by weight, the viscosity becomes so high that uniform coating cannot be performed when coating on a support. If the amount is less than 0.001% by weight, the effect of the present invention by adding cellulose is not exhibited.

In the coating liquid, an aqueous medium comprising water or an organic solvent miscible with water is used as a medium in which cellulose is dispersed. The water-miscible organic solvent referred to herein is dimethylformamide, amides such as dimethylacetamide, ketones such as acetone, ethers such as tetrahydrofuran and dioxane, polyalkylene glycols such as polyethylene glycol and polypropylene glycol, Ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, alkylene glycols such as triethylene glycol, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, lower alkyl ethers of polyhydric alcohols such as triethylene glycol monomethyl ether, ethanol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol,
In addition to alcohols such as glycerin, esterified products of these series of alcoholic compounds, and N-methyl-2
-Pyrrolidone, 1,3-dimethyl-imidazolidinone,
Examples include, but are not limited to, triethanolamine, sulfolane, dimethyl sulfoxide, and the like.

The content of the water-miscible organic solvent is preferably not more than 60% by weight based on the total weight of the coating solution. It is more preferably at most 30% by weight.
When the content is 60% by weight or less, the cellulose dispersion and other components can be uniformly dispersed. If it exceeds 60% by weight, the cellulose dispersion itself will aggregate in the liquid, making it impossible to obtain a uniform liquid mixture.

Next, the coating liquid of the present invention preferably contains fine particles other than cellulose having an average particle diameter of 300 nm or less. The average particle diameter of the fine particles other than cellulose is 300 nm or less, preferably 100 n.
m or less, and more preferably 30 nm or less. 300
If it exceeds nm, a porous material structure suitable for an ink receiving layer cannot be formed, which is not preferable. The lower limit of the particle diameter is preferably 3 nm or more from the viewpoint of particle production.

These fine particles other than cellulose act, for example, as an ink absorbent or a binder. Needless to say, the preferred amount depends on the purpose of use.
For example, when fine particles other than cellulose are used as the ink absorbent, it is preferable to use the additive in an amount of 70% by weight or less based on all solid components of the coating liquid. If it exceeds 70% by weight, the strength of the coating film of the ink absorbing layer is reduced. It is more preferably at most 50% by weight.

For example, when fine particles other than cellulose are used as the binder, the amount of addition is 20% by weight or less based on the total amount of the solid content of the coating solution. 2 added
If it exceeds 0% by weight, the sharpness of the image is lowered, or the fluidity of the coating liquid is lost. It is more preferably at most 15% by weight. Here, the average particle diameter of the fine particles is determined as a simple average value (number average) by observing the particle diameter (primary particle diameter) of 100 arbitrary particles by observing with an electron microscope at the stage of the raw material for coating liquid preparation. Desired. Here, each particle size is represented by a diameter assuming a circle equal to the projected area.

More specifically, fine particles other than cellulose 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, fumed silica, colloidal titanium oxide, alumina sol, colloidal alumina, pseudo boehmite, hydroxylated Inorganic fine particles such as aluminum, lithopone, and zeolite; plastic pigments such as polyethylene, polystyrene, and polyacrylate; conjugated dienes such as styrene-butadiene copolymer and methyl methacrylate-butadiene copolymer Copolymer latex, polyvinyl acetate, vinyl acetate / maleic acid ester copolymer, vinyl acetate / acrylic acid ester copolymer, vinyl acetate copolymer latex such as ethylene / vinyl acetate copolymer, acrylate polymer , Methacrylate polymer, ethylene-acrylate copolymer,
Acrylic polymer or copolymer latex such as styrene / acrylate copolymer, vinylidene chloride copolymer latex or functional group-modified polymer of these polymers with functional group-containing monomer such as carboxyl group Combined latex or the like can be used, but is not limited thereto. One or more of these can be used.

In particular, when fine particles other than cellulose are used to enhance the ink absorbency, it is preferred that the thickness be 100 nm or less, since transparency is high. In this case, it is particularly preferable to use silica-based fine particles such as synthetic amorphous silica, colloidal silica, and fumed silica among the above. Further, as the binder, for example, a hydrophilic polymer can be used for the purpose of improving ink receptivity and coatability. Examples of the hydrophilic polymer include gelatin derivatives such as lime-treated gelatin, acid-treated gelatin, and enzyme-treated gelatin; various gelatins such as gelatin reacted with dibasic acid anhydrides such as phthalic acid, maleic acid, and fumaric acid; Starch, starches such as etherified starch, methylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, carboxymethylcellulose, cellulose derivatives such as hydroxyethylcellulose, polyalkylene oxides and their derivatives, polyacrylic acid, polymethacrylic acid or esters thereof, Salts and their copolymers, polyhydroxyethyl methacrylate and its copolymers, polyvinylpyrrolidone, polyvinylpyridium halide,
Polyvinyl alcohol of various degrees of saponification, carboxy-modified,
Amphoteric polyvinyl alcohol, polyethylene glycol, polypropylene glycol, polyvinyl ether,
Examples include alkyl vinyl ether / maleic anhydride copolymers, styrene / maleic anhydride copolymers, and salts thereof, and synthetic polymers such as polyethyleneimine. These can be used alone or in combination. In addition, for the purpose of improving the strength of the coating film and water resistance, an aldehyde compound, a melamine resin, an activated vinyl compound, an acid anhydride, an isocyanate compound, an activated vinyl compound, a hydroxyl group crosslinking agent such as a polyvalent metal-containing compound are added. No problem.

The preferred amount of the hydrophilic polymer to be added is 20% by weight or less based on the total solid content of the coating solution. If the amount exceeds 20% by weight, the image clarity may be reduced,
Fluidity as a coating liquid is lost. Further, a cation-modified polymer can be further added to the coating liquid in order to improve the fixing property of the ink. The addition amount of the cation-modified polymer is preferably 0.001 to 15% by weight based on the coating solution. If the content exceeds 15% by weight, non-uniformity such as phase separation may be caused, or unsuitable high viscosity (gelation) may be caused as a coating liquid. More preferably 0.01 to
It is in the range of 10% by weight.

The cation-modified polymer is at least one selected from amide groups, imide groups, primary to tertiary amino groups, primary ammonium bases, secondary ammonium bases, tertiary ammonium bases, and quaternary ammonium bases. It is a polymer containing one kind of cationic group. Cationic modified polyvinyl alcohol, polyallylamine or its hydrochloride, polyamine sulfone or its hydrochloride,
Polyvinylamine or its hydrochloride, chitosan or its acetate, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate diethylaminoethyl methacrylate, methylethylaminoethyl acrylate,
Cationic monomers having a primary or secondary tertiary amine such as methylethylaminoethyl methacrylate, dimethylaminostyrene, diethylaminostyrene or methylethylaminostyrene in a side chain, and a quaternary ammonium base derived from these monomers in a side chain One kind of a homopolymer selected from monomers or a copolymer composed of two or more kinds of these monomers is exemplified. However, it is not limited to the above.

In addition, a matting agent such as crystalline cellulose, an antifoaming agent, a coating improver, a thickener, an antistatic agent, an antioxidant, an ultraviolet absorber, a dye, a light fastness improver, and a storability improver. , And the like, and the like, can be used as an additive. These additives can be used in combination of two or more. Anionic surfactants, cationic surfactants, nonionic surfactants, and amphoteric surfactants can be used for the purpose of improving image sharpness.

Examples of the anionic surfactant include fatty acid soaps, N-acyl amino acids and salts thereof, alkyl ether carboxylates, carboxylates such as acylated peptides, sulfated oils, higher alcohol sulfates, and alkyl ethers. Sulfate, polyoxyethylene alkylphenyl ether sulfate, sulfate such as sulfate of fatty acid alkylol amide, alkylbenzene sulfonate, alkyl naphthalene sulfonate, dialkyl sulfosuccinate, alkyl sulfo acetate, α- Sulfonates such as olefin sulfonates,
Phosphoric acid ester salts such as alkyl ether phosphoric acid ester salts and alkyl phosphoric acid ester salts are exemplified.

Examples of the cationic surfactant include aliphatic primary amine salts, secondary amine salts, tertiary amine salts, quaternary ammonium salts, benzalkonium salts, benzenetonium chloride, and pyridinium. Salt, imidazolinium salt,
Saponin and the like. As the amphoteric surfactant,
Carboxybetaine type, aminocarboxylic acid type, imidazolinium betaine type, lecithin type and the like can be mentioned. As nonionic surfactants, polyoxyethylene alkyl ether type, polyoxyethylene alkyl phenyl ether type, polyoxyethylene sterol ether type,
Polyoxyethylene lanolin derivative type, polyoxyethylene glycerin fatty acid ester type, polyoxyethylene sorbitan fatty acid ester type, polyoxyethylene sorbitol fatty acid ester type, polyethylene glycol fatty acid ester type, fatty acid glyceride type, polyglycerin fatty acid ester type, sorbitan fatty acid ester Type, propylene glycol fatty acid ester type, fatty acid alkanolamide type, polyoxyethylene fatty acid amide type, polyoxyethylene alkylamine type, alkylamine oxide type and the like. Of these, nonionic surfactants are preferable, and sorbitan ester ethers such as polyoxyethylene sorbitan fatty acid ester type and polyoxyethylene sorbitol fatty acid ester type, and polyoxyethylene alkylphenyl ether type are particularly preferable.

The amount of the surfactant is preferably 1% by weight or less based on the solid content of the coating solution. If it exceeds 1% by weight, bleeding of the ink may occur. Hereinafter, a method for preparing the coating liquid for an inkjet recording medium of the present invention will be described. As the cellulose in the present invention, it is preferable to use a cellulose dispersion dispersed in a dispersion medium such as water obtained by a production method described below. A cellulose dispersion is dissolved in a mineral acid (for example, an aqueous sulfuric acid solution) capable of dissolving raw cellulose such as pulp in an amount of 50% by weight or more, and an acid dispersion of a cellulose aggregate obtained by reprecipitating the solution in water is used. After heating, the solid phase is subjected to a hydrolysis treatment in a temperature range of 50 to 100 ° C. The reaction time varies depending on the temperature, but is desirably in the range of about 5 minutes to 180 minutes.

The dispersion obtained in this step is purified by repeating filtration and washing with water. During this time, neutralization may be performed with an alkaline aqueous solution such as dilute ammonia water. However, in this case, it is preferable to further wash with water after the neutralization to wash out the neutralized salt generated by the neutralization. The pH value thus obtained is 2 or more, preferably 4
The above gel-like substance is used as it is, or after being mixed or replaced with an organic solvent such as ethanol, and then subjected to a fine treatment to prepare an aqueous dispersion of cellulose or a dispersion in an organic solvent. At this time, application of an ultrahigh-pressure homogenizer, a bead mill, an ultrasonic treatment, or the like is effective as the fine processing. The final fine processing may be performed a plurality of times as necessary. Natural cellulose such as wood pulp or cotton can be suitably used as the starting cellulose, but regenerated cellulose may be used.

Next, the above-mentioned various additives are appropriately added to the cellulose dispersion thus obtained, and the mixture is subjected to a mixing treatment according to the purpose to produce a coating liquid containing cellulose. For example,
The cellulose dispersion and, if necessary, additives such as a surfactant are preliminarily mixed in an aqueous medium, and then uniformly dispersed to obtain a coating liquid for an ink jet recording medium. The inkjet recording medium of the present invention has an average degree of polymerization (DP) of 100 or less, a fraction of cellulose type I crystal component of 0.1 or less, and a cellulose I
It has an ink receiving layer containing 0.01% by weight or more of cellulose having a fraction of type I crystal component of 0.4 or less.

The ink-jet recording medium is coated with the above-mentioned coating liquid for an ink-jet recording medium containing cellulose directly on one or both sides of a support and dried to form an ink-receiving layer. It is obtained by doing.
Also, on the surface of the support on which the ink receiving layer is to be formed,
A coating liquid containing an ink absorbent and a binder and containing no cellulose is applied to form a coating layer (hereinafter, referred to as a lower layer), and the above-mentioned coating liquid for cellulose-containing inkjet recording medium is applied thereon. It is also obtained by forming an ink receiving layer by working and drying.
The dried ink receiving layer containing this cellulose is hydrophilic but water-insoluble.

The content of cellulose in the ink receiving layer is as follows:
0.01% by weight or more, preferably 0.05 to 70% by weight
And more preferably in the range of 0.5 to 50% by weight. When the content is less than 0.01% by weight, the effect of adding cellulose in the present invention is not exhibited. If the content exceeds 70% by weight, a dense layer is formed due to the strong cohesiveness of cellulose, so that some measure to increase the ink absorption tends to be required.

The function as an ink receiving layer can be controlled by selecting the cellulose content and the compounding components. Furthermore, cellulose acts as a different functional material depending on the content of cellulose in the ink receiving layer depending on whether the content is roughly low (0.01 to 5% by weight) or high (5% by weight or more). About 0.01-5% by weight
In the range, the cellulose acts as an additive as an additive. In the case of the addition amount in this range, it is desirable to add a hydrophilic polymer or the like as a binder in addition to the cellulose. By containing cellulose, it is possible to impart a matting effect while maintaining, for example, ink receptivity, color development and transparency. Other components in the ink receiving layer, for example, silica fine particles as an ink absorbent, hydrophilic polymer as a binder, etc. are uniformly dispersed, in addition to the ink absorbency of the cellulose itself, to improve the color development, A homogeneous image can be obtained.

In the range of about 5% by weight or more, cellulose also functions as an ink absorbent and a binder. 10
When the content is more than 10% by weight, under appropriate conditions, the coloring agent and the transparency are maintained, and as an ink absorbing agent for improving the ink absorbing property, or a dye, a pigment and other ink absorbing agents are uniformly dispersed and fixed. It can function as a binder. Even when cellulose is contained in the range of 5% by weight or more, it is realistic to use other binders and ink absorbents. However, especially when the content is 50% by weight or more, other binders and ink absorbents are not used. It is also possible to express the function with. In particular, in the case of a high content, it is possible to improve the coating film strength and the water resistance by crosslinking cellulose.

In the present invention, the ink receiving layer may be a single layer or two or more layers, and in the case of two or more layers, the cellulose-containing layer used in the present invention may be any one of them. It may be a part layer or all layers, but from the viewpoint of ink absorbability, it is preferable to have at least the uppermost layer. The thickness of the ink receiving layer provided on the support of the inkjet recording medium of the present invention is 0.5
It is preferably from 100 to 100 μm. 0.5μm thickness
If it is less than 7, the ink bleeds, and the strength of the coating film decreases. 1
If it exceeds 00 μm, the drying property, coating property and curling property during coating are insufficient. Preferably it is in the range of 1 to 50 μm.

The support used in the present invention may be transparent or opaque, depending on the purpose. The support is generally a paper or a film including processed paper, but is not particularly limited thereto.A solid material can be used as long as it functions as a support for an inkjet recording medium. It may be a glass plate, a metal plate, or the like. Examples of the film material include a synthetic resin film. Examples of the synthetic resin film include polyester, polyolefin, polyamide, polyesteramide, polyether, polyimide, polyamideimide, polystyrene, polycarbonate, and poly-P.
Phenylene sulfide, polyetherester, polyvinylchloride, polyvinylacetate, poly (meth) acrylate and the like can be used. Furthermore, these copolymers and blends and further cross-linked products, or opaque films by incorporating pigments, foamed films,
A gloss film or the like can also be used.

Further, in the present invention, between the ink-receiving layer containing cellulose and the support, no cellulose is contained.
It is preferable to provide a lower layer containing an ink absorbent and a binder, and particularly, the degree of nitrate ester group substitution is 0.2 to
2.95, the degree of carboxyalkyl ether group substitution is 0.
A lower layer containing 3-80% by weight, preferably 5-35% by weight, of nitric acid esters of carboxyalkylcellulose of 0.05-2.8, and 20-97% by weight, preferably 65-95% by weight of an aqueous polymer. Is preferably provided. By providing the lower layer, an ink jet recording medium having excellent water resistance and excellent ink absorbency can be provided.

When the degree of nitrate group substitution is less than 0.2,
The water resistance of the lower layer is insufficient, and if it exceeds 2.95, the hydrophilicity becomes insufficient. If the carboxyalkyl ether group substitution degree is less than 0.05, the solubility in water becomes insufficient,
If the ink absorbency of the lower layer becomes insufficient, and if it exceeds 2.8, the water resistance of the lower layer becomes insufficient. The preferred range of the degree of substitution of the nitrate group of the nitrates of carboxyalkyl cellulose is 0.2 to 2.2, and the preferred range of the degree of substitution of the carboxyalkyl ether group is 0.05 to 1.
5

The aqueous polymer which can be used for the lower layer of the present invention is
The hydrophilic polymer and the cation-modified polymer used as a binder in the above-mentioned coating liquid for an ink jet recording medium can be used. Specifically, lime-treated gelatin, acid-treated gelatin, gelatin derivatives such as enzyme-treated gelatin, for example, phthalic acid, maleic acid, various gelatins such as gelatin reacted with dibasic acid anhydrides such as fumaric acid, oxidized starch, Starches such as etherified starch, methylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, carboxymethylcellulose, cellulose derivatives such as hydroxyethylcellulose, polyalkylene oxides and their derivatives, polyacrylic acid, polymethacrylic acid or esters, salts and Their copolymers, polyhydroxyethyl methacrylate and its copolymers, polyvinylpyrrolidone, polyvinylpyridium halide, polyvinyl alcohol of various degrees of saponification, carbohydrate Poly-modified, amphoteric polyvinyl alcohol, cation-modified polyvinyl alcohol, cation-modified cellulose derivative, cation-modified starch, cation-modified guar gum, diallyl quaternary ammonium salt polymer, copolymer of diallyl quaternary ammonium salt and acrylamide, aniline resin, Cationically modified polymers such as polythiourea, polyethyleneimine, polyvinylpyridines, polyethylene glycol, polypropylene glycol, polyvinyl ether, alkyl vinyl ether / maleic anhydride copolymer, styrene / maleic anhydride copolymer, and salts thereof, polyethylene Synthetic polymers such as imine, styrene-butadiene copolymer,
Conjugated diene-based copolymer latex such as methyl methacrylate / butadiene copolymer, polyvinyl acetate, vinyl acetate / maleic ester copolymer, vinyl acetate / acrylic ester copolymer, ethylene / vinyl acetate copolymer, etc. Latex of vinyl acetate copolymer latex, acrylic polymer or copolymer such as acrylate polymer, methacrylate polymer, ethylene acrylate copolymer, styrene acrylate copolymer, Aqueous adhesives such as vinylidene chloride-based copolymer latex or functional group-modified polymer latex with functional group-containing monomers such as carboxyl groups of these various polymers, thermosetting synthetic resins such as melamine resin and urea resin And polymethyl methacrylate, polyurethane resin, Sum polyester resins, vinyl chloride-vinyl acetate copolymers, polyvinyl butyral, may be mentioned synthetic resins such as alkyd resins. These can be used alone or in combination.

Among these, it is preferable to use a cation-modified polymer in that the ink fixability can be improved. The cation-modified polymer includes an amide group, an imide group, a primary to tertiary amino group, a primary ammonium base,
It is a polymer containing at least one kind of cationic group selected from a secondary ammonium base, a tertiary ammonium base, and a quaternary ammonium base. To give a concrete example,
Cation-modified polyvinyl alcohol, polyallylamine or its hydrochloride, polyamine sulfone or its hydrochloride, polyvinylamine or its hydrochloride, chitosan or its acetate, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate,
Diethylaminoethyl acrylate diethylaminoethyl methacrylate, methylethylaminoethyl acrylate, methylethylaminoethyl methacrylate,
One selected from cationic monomers having a primary or secondary tertiary amine such as dimethylaminostyrene, diethylaminostyrene or methylethylaminostyrene in a side chain, and monomers having a quaternary ammonium base derived from these monomers in a side chain Or a copolymer of two or more of these monomers.

It is particularly preferable to use cation-modified polyvinyl alcohol. The cation-modified polyvinyl alcohol referred to herein is an amide group, an imide group, a primary amino group, a secondary amino group, a tertiary amino group, a primary ammonium base, a secondary ammonium base, a tertiary ammonium base,
Polyvinyl alcohol containing at least one kind of cation group selected from quaternary ammonium bases and having a cation modification amount of 0.01 mol% or more. The preferred range of the cation conversion amount is 0.1 to 30 mol%. Furthermore, 0.1 to 15 mol% is preferable. If the amount of modification of the cationic group is less than 0.01 mol%, the water resistance of the coating film becomes insufficient, which is not preferable. The average degree of saponification is 40 to 10
0 mol% is preferred. When the saponification degree is less than 40 mol%, the ink absorbency becomes insufficient. The average degree of polymerization is 100
~ 5000 is preferred. Further, 200 to 3000 is preferable. If the average degree of polymerization is less than 100, the water resistance of the lower layer is reduced, and if it exceeds 5,000, the solution viscosity is too high, and the workability such as mixing of the resin and coating on the support deteriorates.

For the purpose of improving the strength and water resistance of the coating film, a hydroxyl group crosslinking agent such as an aldehyde compound, a melamine resin, an activated vinyl compound, an acid anhydride, an isocyanate compound, an activated vinyl compound, and a compound containing a polyvalent metal. Is mentioned. The preferable addition amount of the hydroxyl group crosslinking agent is 0.1% by weight to 20% by weight based on the total amount of the carboxyalkyl cellulose nitrates and the aqueous polymer. If the amount is less than 0.1% by weight, water resistance may not be sufficiently exhibited, and if it exceeds 20% by weight, the image clarity of the dye ink may be reduced.

Depending on the intended use of the ink jet recording medium, light calcium carbonate, bicarbonate calcium carbonate, magnesium carbonate, kaolin, clay, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc hydroxide, zinc sulfide, zinc carbonate Inorganic particles such as hydrotalcite, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate, synthetic amorphous silica, colloidal silica, fumed silica, alumina, colloidal alumina, pseudoboehmite, aluminum hydroxide, lithopone, zeolite Polymer pigments, which are organic fine particles, can be used in the lower layer as an ink absorbent. The addition amount of these fine particles is preferably 70% by weight or less, more preferably 50% by weight or less, based on all components of the lower layer.

Further, in the lower layer containing a nitric acid ester of carboxyalkylcellulose, an anionic surfactant, a cationic surfactant, a nonionic surfactant, Amphoteric surfactants can also be used. Examples of anionic surfactants include fatty acid soaps, N-acyl amino acids and salts thereof, alkyl ether carboxylates, carboxylates such as acylated peptides, sulfated oils, higher alcohol sulfates, alkyl ether sulfates, Polyoxyethylene alkyl phenyl ether sulfate, sulfate such as fatty acid alkylol amide sulfate, alkyl benzene sulfonate, alkyl naphthalene sulfonate, dialkyl sulfosuccinate, alkyl sulfo acetate, α-olefin sulfonic acid Sulfonates such as salts,
Phosphoric acid ester salts such as alkyl ether phosphoric acid ester salts and alkyl phosphoric acid ester salts are exemplified.

Examples of the cationic surfactant include aliphatic primary amine salts, secondary amine salts, tertiary amine salts, quaternary ammonium salts, benzalkonium salts, benzenetonium chloride, and pyridinium. Salt, imidazolinium salt,
Saponin and the like. As the amphoteric surfactant,
Carboxybetaine type, aminocarboxylic acid type, imidazolinium betaine type, lecithin type and the like can be mentioned. As nonionic surfactants, polyoxyethylene alkyl ether type, polyoxyethylene alkyl phenyl ether type, polyoxyethylene sterol ether type,
Polyoxyethylene lanolin derivative type, polyoxyethylene glycerin fatty acid ester type, polyoxyethylene sorbitan fatty acid ester type, polyoxyethylene sorbitol fatty acid ester type, polyethylene glycol fatty acid ester type, fatty acid glyceride type, polyglycerin fatty acid ester type, sorbitan fatty acid ester Type, propylene glycol fatty acid ester type, fatty acid alkanolamide type, polyoxyethylene fatty acid amide type, polyoxyethylene alkylamine type, alkylamine oxide type and the like. Of these, nonionic surfactants are preferable, and sorbitan ester ethers such as polyoxyethylene sorbitan fatty acid ester type and polyoxyethylene sorbitol fatty acid ester type, and polyoxyethylene alkylphenyl ether type are particularly preferable.

The amount of the surfactant added is preferably 0.1% by weight to 20% by weight, more preferably 0.1% by weight to 10% by weight, based on the total amount of the carboxyalkyl cellulose nitrate and the aqueous polymer. % By weight. When the content is less than 0.1% by weight, the effect of improving image clarity is not remarkable, and when it is more than 20% by weight, ink bleeding may occur. A pH adjuster can be used for the purpose of improving the water resistance of the lower layer.
Inorganic acids and organic acids can be used as the pH adjuster, but organic acids are preferred from the viewpoint of the stability of the coating solution for forming the lower layer.
Among them, organic acids having a logarithm of the reciprocal of the acid dissociation constant in water at 25 ° C. of 1 to 6 are preferable. In this case, the monobasic acid, n
Regardless of the basic acid, the logarithm of the reciprocal of the acid dissociation constant indicates the value of the first stage dissociation. Examples of these organic acids include oxalic acid, malonic acid, succinic acid, adipic acid, maleic acid, dicarboxylic acids such as itaconic acid, fatty acids such as formic acid, acetic acid, propionic acid, and butyric acid, glycolic acid, lactic acid, and malic acid. And oxyacids such as tartaric acid and citric acid. The preferred pH of the coating solution obtained by using the pH adjuster is 2 to 8, more preferably 4 to 7.

When the pH is more than 8, the effect of improving the water resistance of the lower layer is low, and when the pH is less than 2, the workability such as thickening of the solution occurs and the workability is reduced. In addition, matting agents such as calcium carbonate, basic magnesium carbonate and crystalline cellulose, defoaming agents, coating improvers, thickeners, antistatic agents, antioxidants,
An ultraviolet absorber, a dye, a light resistance improver, a storage stability improver, a printability improver such as alumina sol, or the like can be used as an additive. These can be used in combination of two or more.

The thickness of the lower layer containing the carboxyalkyl cellulose nitrates of the present invention is 0.5 to 10%.
It is preferably 0 μm, more preferably 1 to 50 μm. The nitric acid esters of carboxyalkyl cellulose that can be used in the present invention are dissolved in water and / or an organic solvent containing water as a main component to prepare a coating solution. In order to increase the solubility in these solvents, it is preferable to neutralize some or all of the carboxyl groups contained in the nitrates of carboxyalkyl cellulose. For neutralization, one of cations such as alkali metal ion, alkaline earth metal ion, ammonium ion and organic amine is used.
Species or two or more species can be used. In this case, the degree of neutralization is arbitrarily determined according to the composition of the target solution such as water and an organic solvent. Generally, 50% or more of the carboxyl groups contained are neutralized. Is preferred. Neutralizing the carboxyalkylcellulose nitrates lowers the viscosity of the solution and improves coatability on the support.

The organic solvent which can be used for dissolving the carboxyalkylcellulose nitrates which can be used in the lower layer of the ink-receiving layer containing cellulose in the present invention includes:
Solvents composed of one or a combination of two or more selected from alcohols, polyhydric alcohols, derivatives of polyhydric alcohols, ketones, esters, carbonates and the like. As alcohols, methanol, ethanol, n-propanol, n-butanol,
Examples include n-pentanol, n-hexanol, n-heptanol, n-octanol, n-nonyl alcohol, n-decanol, n-undecanol or isomers thereof, cyclopentanol, cyclohexanol and the like. Preferred are alcohols having 1 to 6 alkyl carbon atoms.

The polyhydric alcohols include ethylene glycol, propylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 2-cyclohexanediol, 1,7
-Heptanediol, 1,8-octanediol, 1,
Examples include 9-nonanediol, 1,10-decanediol, glycerin, pentaerythritol and the like. Derivatives of polyhydric alcohols include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol isopropyl ether, ethylene glycol monobutyl ether, ethylene glycol isobutyl ether, propylene glycol monomethyl ether,
Propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, cellosolve acetate, etc., or a solvent pocket book (p. 479-
p, 574), (September 20, 1990, published by Ohmsha), and polyhydric alcohols and derivatives thereof.

Examples of the ketones include acetone, methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, diisopropyl ketone, cyclopentanone, cyclohexanone and the like. Esters include methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, amyl acetate, lactate ester, butyrate ester, dibutyl phthalate, dioctyl phthalate, and cyclic compounds such as ε-caprolactone and ε-caprolactam. Esters are mentioned. Examples of ethers include diethyl ether, isopropyl ether, n-butyl ether, tetrahydrofuran, tetrahydropyran, 1,4-dioxane and the like. Examples of the carbonates include dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, ethylene carbonate and the like.

The method for forming the ink receiving layer and the lower layer of the ink jet recording medium of the present invention comprises an air doctor coater,
Known methods such as rod coater, knife coater, reverse roll coater, transfer roll coater, kiss coater, cast coating, spray coater, slot orifice coater, calendar coater, blade coater, gravure coater, curtain coater, roll coater and the like can be applied. it can. At this time, the coatability is improved by subjecting the support to a known surface treatment such as corona discharge treatment or primer treatment in the air or other atmosphere, if necessary, before coating. If necessary, a binder may be applied to both sides of the support, or a coating film having different physical properties may be laminated on the support. The concentration of the coating solution and the conditions for drying the coating film are not particularly limited, but the drying conditions for the coating film are desirably in a range that does not adversely affect the properties of the substrate. The ink jet recording medium obtained by coating the coating liquid of the present invention is particularly excellent in acceptability of dye ink and pigment ink.

[0057]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail with reference to examples. In the following Examples and Comparative Examples, the average particle size,
The fraction of the crystal component and the average degree of polymerization (DP) were measured by the above-mentioned measuring methods.

[0058]

Preparation Example An aqueous dispersion of cellulose was prepared. 5mm ×
A sulfite pulp sheet (DP = 760) cut into 5 mm chips was uniformly dissolved in a 65% by weight aqueous sulfuric acid solution at −5 ° C. so that the cellulose concentration was 6% by weight, to obtain a cellulose dope. The cellulose dope was poured into 2.5 times by weight of water (5 ° C.) while stirring, and the cellulose was precipitated and aggregated in flocs to form a suspension (15%).
° C). This suspension is hydrolyzed at 85 ° C. for 60 minutes, and then sufficiently washed with water and dehydrated under reduced pressure until the pH becomes 4 or more, and a white paste-like transparent white paste having a cellulose concentration of 6.5% by weight is obtained. A gel was obtained. The gel was diluted with ion-exchanged water to a cellulose concentration of 4.0% by weight, and mixed with a blender at a rotation speed of 10,000 rpm for 5 minutes. This diluted sample was subjected to an ultra-high pressure homogenizer (Microfluidizer M-110EH,
The product was treated four times with an operating pressure of 1.7 × 10 ⁵ MPa manufactured by Mizuho Industry Co., Ltd. to obtain a highly transparent cellulose dispersion (sample J1). The cellulose of the J1 sample had a DP of 32,
_I is 0.0, χ _II is 0.31, average particle size is 0.28μ
m.

[0059]

Example 1 Preparation of Coating Liquid 1: Fumed silica having an average primary particle diameter of 12 nm (A200 manufactured by Nippon Aerosil Co., Ltd.)
After adding 0 g to 400 ml of pure water and dispersing with an emulsifying and dispersing machine, 20 ml of the cellulose dispersion J1 obtained in the preparation example was added to the uniformly dispersed silica dispersion having a total amount of 450 ml with pure water. , 40 g of cation-modified polymer (Sumitomo Chemical Sumirezuresin 1001) (solid content 3
0% by weight), 35 ml of ethanol, 8.0 g of a 10% by weight aqueous solution of polyvinyl alcohol (PVA203 manufactured by Kuraray Co., Ltd.), 2.0 g of boric acid, and 2.0 g of borax. Then, a high pressure homogenizer manufactured by Sanwa Kogyo Co., Ltd.
It was dispersed under the condition of 00 kg / cm ² to obtain a uniform and almost transparent dispersion. While heating and stirring this dispersion at 50 ° C., polyvinyl alcohol (PVA2 manufactured by Kuraray Co., Ltd.) was used.
35) 240 g of a 5% by weight aqueous solution was added to obtain a substantially transparent coating liquid 1. Production of inkjet recording medium 1: 100 μm thick white PET film (Lumirror 100E0 manufactured by Toray Industries, Inc.)
8J) was used as a support, and the coating liquid 1 heated to 50 ° C. was applied using an applicator so as to have a film thickness of 20 μm, and then dried at room temperature to obtain an ink jet recording medium.

[0060]

[Comparative Example 1] Preparation of coating liquid 2: A dispersion obtained by adding 20 ml of a 4% by weight aqueous solution of a surfactant saponin instead of the cellulose dispersion in the composition of coating liquid 1 was used. Production of Inkjet Recording Medium 2: Inkjet recording medium 2 was obtained by applying coating liquid 2 in the same manner as inkjet recording medium 1 of Example 1. The performance evaluation of the recording medium was performed by the following method.

The recording medium produced in Example 1 and Comparative Example 1 was used as an ink jet printer EPSON PM-80.
Printing was performed in high-resolution PM photo paper mode using 0C. Glossiness: Glossiness (relative reflection intensity with respect to a gloss standard plate) at an angle of 60 was measured using a gloss meter GM-268 manufactured by Minolta Industry Co., Ltd. Light transmittance / cloudiness: A transparent PET film (Lumirror Q80D manufactured by Toray Industries, Inc.) was used as a support and the coating was measured. Lumirror Q80D was used as a reference value. Color density: Macbeth densitometer (RD-914, manufactured by Macbeth) Lightfastness test: Measured with Suntest CPS + (manufactured by Atlas) under the following conditions. Irradiation was performed using Filter C at an irradiation light intensity of 750 W / m ² and BST = 60 ° C. for 60 hrs. (5.5 years of sunlight through a window) The fading rate was calculated from the following formula based on the initial color density and the color density after irradiation. Fading rate (%) = ((color density after irradiation) − (initial color density)) / (initial color density) * 100 Table 1 shows the measurement results of Example 1 and Comparative Example 1. As a reference example, the results using Epson PM photo paper (glossy paper) are shown.

[0062]

[Table 1]

[0063]

Example 2 <Production of Coating Solution for Forming Lower Layer> Carboxymethylcellulose (Selogen 5A; Daiichi Kogyo Seiyaku Co., Ltd.)
Carboxymethyl ether group substitution degree = 0.7) 10
0 g, sulfuric acid / nitric acid / water (= 59/20/21 parts by weight)
Into a 5 liter reaction vessel,
The nitrification reaction is performed while stirring at -10 ° C for 60 minutes. The reaction product is deacidified by centrifugation and immediately washed with a large amount of water. The reaction product was dried at 80 ° C. for 2 hours,
0 g of carboxymethylcellulose nitrate was obtained. The nitrate ester substitution degree per anhydroglucose unit of this nitrate ester is the carboxymethyl ether group substitution degree (0.7) of carboxymethyl cellulose,
Measurement of the nitrogen content with a CHN coder (manufactured by Yanagita Seisakusho Co., Ltd., MT2 type) revealed that the nitrogen content was 1.9.

Next, 50 g of carboxymethylcellulose nitrate having a degree of substitution of 1.9 and a degree of substitution of carboxymethyl ether of 0.7 per unit of anhydrous glucose unit and 50 g of ion-exchanged water were used.
5.7 g and 300 g of isopropyl alcohol were put into a closed mixer and stirred. Further, 14.3 g of 10% by weight aqueous ammonia was added as a neutralizing agent. The solution was completely dissolved with heating to obtain a solution having a solid content of 5% by weight (this is referred to as a coating solution A).

Cation-modified polyvinyl alcohol (CM318 manufactured by Kuraray Co., Ltd.) 50 g, ion-exchanged water 850 g,
100 g of isopropyl alcohol was put into a mixer and stirred until completely dissolved to obtain a solution having a solid content of 5% by weight (this is referred to as a coating solution B). The coating liquid C was prepared by mixing the coating liquid A and the coating liquid B at a weight ratio of 20:80. <Formation of Lower Layer> A transparent polyethylene terephthalate film having a thickness of 100 μm (Melinex D53 manufactured by DuPont)
In 5), a coating solution C was applied by a rod coater so that the film thickness became 10 to 15 μm, and dried at 80 ° C. for 15 minutes to form a lower layer.

Next, the coating liquid D was adjusted so that the weight ratio of the cellulose J1 / emulsifier (Emulgen 935; manufactured by Kao, HLB = 17.5) / ethanol obtained in the Preparation Example was 1 / 0.5 / 25. Then, after coating on the lower layer with a rod coater, the coating was dried at 60 ° C. for 30 minutes to obtain an ink jet recording medium. The method for measuring the characteristics of the ink jet recording medium is as follows. <Method for evaluating pigment ink receptivity> Solid printing is performed on an inkjet recording medium using an inkjet printer (HP694C; manufactured by Hewlett-Packard Company). The degree of cracking of the pigment ink after recording was visually determined. ：: No cracking △: Some cracking ×:
Poor <Evaluation method of water resistance> A solid printed ink jet recording medium was immersed in water at room temperature for 1 minute, and the degree of outflow of the ink was visually evaluated.

：: No outflow Δ: Slight outflow
X: Outflow of coating film <Ink absorption speed> Copy paper was superimposed on a solid printed ink jet recording medium, and the presence or absence of ink transfer was examined. ：: Transfer of ink is hardly recognized. ：: Transfer is present but there is no problem in practical use. Out of practical range. <Transparency> The transparency of the image projected by the OHP projector was visually determined. ：: bright, high-resolution image △: slightly darkened part, but acceptable as a whole. ×: Some parts lack brightness and sharpness. The evaluation result of the second embodiment is as follows.

Pigment ink acceptability: 水性 Water resistance: 速度 Absorption rate: Transparency: ○

[0069]

Comparative Example 2 A coating solution B was applied to a 100 μm-thick transparent polyethylene terephthalate film (Melinex D535 manufactured by DuPont) with a rod coater so as to have a film thickness of 10 to 15 μm, dried at 80 ° C. for 15 minutes, and inkjet-printed. A recording medium was obtained. The evaluation result is as follows. Pigment ink acceptability: × Water resistance: × Absorption rate: × Transparency: ○

[0070]

Comparative Example 3 Transparent polyethylene terephthalate film having a thickness of 100 μm (Melinex D535) was applied to coating liquid C.
Was coated with a rod coater so that the film thickness became 10 to 15 μm, and dried at 80 ° C. for 15 minutes to obtain an ink jet recording medium. The evaluation result is as follows. Pigment ink acceptability: △ Water resistance: ○ Absorption rate: △ Transparency: ○

[0071]

EFFECTS OF THE INVENTION By using the coating liquid of the present invention, ink jet recording having excellent light fastness, excellent receptivity of dye ink and pigment ink, excellent color development and transparency, and improved ink absorption speed. Thus, an ink jet recording medium having a reduced surface gloss (matte) can be obtained.
The ink jet recording medium thus obtained can provide high-definition images, and thus is very useful for OHP sheets, calendars, stickers (such as stickers), cards (such as business cards), and large format posters.

[Brief description of the drawings]

FIG. 1. Fraction of cellulosic type I crystal component (ロ ス_I ) and II
FIG. 3 is a schematic diagram showing how to determine the fraction (χ _II ) of a type crystal component.

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] June 16, 2000 (2006.1.
6)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 5

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction contents]

That is, the present invention provides [1] an average degree of polymerization (D
P) is 100 or less, the fraction of the cellulose type I crystal component is 0.1 or less, the fraction of the cellulose type II crystal component is 0.4 or less, and the average particle diameter of the constituting cellulose particles is 5 or less.
[2] A coating liquid for an inkjet recording medium containing 0.001 to 5% by weight of cellulose having a particle size of not more than μm, wherein the coating solution contains fine particles other than cellulose having an average particle size of not more than 300 nm. [1] The coating liquid for an ink jet recording medium according to [1] or [2], wherein the coating liquid for an ink jet recording medium according to [1] contains [3] a cation-modified polymer in an amount of 0.001 to 15% by weight. [4] An ink jet recording medium having an ink receiving layer on at least one surface of a support, wherein the ink receiving layer has an average degree of polymerization (DP) of 100.
Below, the fraction of the cellulose type I crystal component is 0.1 or less,
An ink-jet recording medium comprising 0.01% by weight or more of cellulose having a cellulose II type crystal component fraction of 0.4 or less, [5] 3 in the ink receiving layer.
[4] The ink jet recording medium according to [4], which contains fine particles other than cellulose having an average particle diameter of 00 nm or less, [6] The ink receiving layer contains 40% by weight or less of a cation-modified polymer. The inkjet recording medium according to [4] or [5],
[7] The degree of nitrate group substitution per anhydroglucose unit between the support and the ink receiving layer is 0.2 to 0.2.
A lower layer containing 3-80% by weight of a carboxyalkyl cellulose nitrate having a degree of carboxyalkyl ether group substitution of 0.05 to 2.8 and 20 to 97% by weight of an aqueous polymer. The inkjet recording medium according to [4], [5] or [6], wherein the aqueous polymer is a cation-modified polymer. ,.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0022

[Correction method] Change

[Correction contents]

Next, the coating liquid of the present invention preferably contains fine particles other than cellulose having an average particle diameter of 300 nm or less. The average particle diameter of the fine particles other than cellulose is 300 nm or less, preferably 100 n.
m or less, and more preferably 30 nm or less. 300
If it exceeds nm, a porous structure suitable for an ink receiving layer
It is not preferable because the structure cannot be formed. The lower limit of the particle diameter is preferably 3 nm or more from the viewpoint of particle production.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Shinji Funakoshi 1-3-1 Yoko, Kawasaki-ku, Kawasaki-shi, Kanagawa F-term in Asahi Kasei Kogyo Co., Ltd. 2H086 BA15 BA16 BA34 BA35 BA41 BA45 4D075 CA35 DA04 DB18 DC27 EB31 EB57

Claims (8)

[Claims] An average degree of polymerization (DP) of 100 or less, a fraction of a cellulose type I crystal component of 0.1 or less,
A coating for an ink jet recording medium, comprising 0.001 to 5% by weight of cellulose having a fraction of type I crystal component of 0.4 or less and an average particle size of cellulose particles of 5 μm or less. Working fluid. 2. The coating liquid for an ink jet recording medium according to claim 1, further comprising fine particles other than cellulose having an average particle diameter of 300 nm or less. 3. The method according to claim 1, wherein the cation-modified polymer is 0.001 to 1
The coating liquid for an ink jet recording medium according to claim 1, wherein the coating liquid is contained in an amount of 5% by weight. 4. An ink jet recording medium having an ink receiving layer on at least one surface of a support, wherein the ink receiving layer has an average degree of polymerization (DP) of 100 or less and is made of cellulose.
1. An ink jet recording medium comprising 0.01% by weight or more of cellulose having a fraction of I-type crystal component of 0.1 or less and a fraction of cellulose II-type crystal component of 0.4 or less. 5. The ink jet recording medium according to claim 4, wherein the ink receiving layer contains fine particles other than cellulose having an average particle diameter of 100 nm or less. 6. The ink jet recording medium according to claim 4, wherein the ink receiving layer contains 40% by weight or less of a cation-modified polymer. 7. The degree of nitrate ester substitution per anhydroglucose unit between the support and the ink receiving layer is 0.1 to 10.
2 to 2.95, containing 3 to 80% by weight of a carboxyalkyl cellulose nitrate having a carboxyalkyl ether group substitution degree of 0.05 to 2.8, and 20 to 97% by weight of an aqueous polymer. 7. The ink jet recording medium according to claim 4, which has a lower layer. 8. The ink jet recording medium according to claim 7, wherein the aqueous polymer is a cation-modified polymer.