JPH0976627A - Binder of ink jet recording sheet and recording sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a binder of an ink jet recording sheet capable of forming an ink receiving layer good in ink absorbability, drying properties, water resistance and blocking resistance. SOLUTION: A binder of an ink jet recording sheet contains nitric ester of carboxy alkyl cellulose wherein a degree of substitution of nitric ester per at least one anhydrous glucose unit is 0.2-2.95 and a degree of substitution of a carboxyalkyl group is 0.05-2.8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a binder for an ink jet recording sheet and a recording sheet, and more specifically, it has good ink absorbability, fixability and dryness, and water resistance and heat blocking resistance. The present invention relates to a binder for an inkjet recording sheet capable of forming a good ink receiving layer and a recording sheet containing the binder.

[0002]

2. Description of the Related Art Conventional recording methods include:
Various recording methods such as a wire dot recording method, a heat-sensitive color recording method, a heat-melting thermal transfer recording method, a heat-sensitive sublimation transfer recording method, an electrophotographic recording method, and an inkjet recording method are known. Among these, the ink jet method is characterized in that plain paper can be used as a recording sheet, printing cost is low, the apparatus is compact and noise-free, high-speed recording is possible, and colorization is possible.
For this reason, characters created by computers etc.,
Attention has been paid to its use as a printer that outputs image information such as graphics at high speed and accuracy. In addition, since it is easy to colorize and the picture is clear, the image information created by the computer is recorded on a transparent recording sheet by an inkjet printer, and this is used as a manuscript for an overhead projector (OHP) or the like, at conferences, various academic conferences, etc. The demand for use in announcements is increasing.

Recording methods for ink jet printers are roughly classified into a continuous method in which ink that is continuously ejected is selectively landed on a paper surface, and a drop-on-demand method in which ink is selectively ejected. At present, the drop-on-demand method has become mainstream. In the drop-on-demand method, a recording ink is ejected by the pressure of a minute piezoelectric element (piezo element), or by the pressure of air generated by heating of a thermal head, it is ejected from a nozzle and attached to a recording sheet. A bubble jet method for recording is generally adopted. Ink jet recording has a simple mechanism in which the process is completed by ejecting ink, which is a coloring material, directly onto the recording paper, and therefore, a large problem is imposed on the recording head and the ink.
For the ink, it is required to improve the ejection failure of the ink caused by the increase in the viscosity due to the drying of the ink. In general, the components of this ink are generally prepared by dissolving dyes, resins, additives, etc. in water and alcohol.

Further, it is required for a recording material for recording with an ink jet printer to absorb the water content of the attached ink and dry and solidify the ink. For this reason, a recording sheet is used in which an ink receiving layer is formed on a resin film to enhance ink absorption. The following characteristics are required for the ink receiving layer of such a recording sheet.

[0005] 1. Good ink receptivity, absorption and drying, and fixability. 2. Excessive spread of ink dots and less bleeding. 3. Blocking does not occur when stored in a laminated state. 4. Being tacky and free of fingerprints. 5. The yellowing of the recording sheet itself is unlikely to occur.

From such a point of view, the following is known as an ink jet recording sheet in which an ink receiving layer is formed on a recording material to enhance ink absorbency.
As an ink jet recording material with improved ink absorption, a recording sheet having an ink receiving layer made of a water-soluble resin such as polyvinylpyrrolidone or polyvinyl alcohol on a support such as paper, a plastic film or a glass plate, or silica, etc. A recording sheet provided with an ink receiving layer containing the above-mentioned filler is known, and is disclosed in, for example, JP-A-55-1.
46786, JP-A-56-99692, JP-A-59-174381, JP-A-2-27667.
No. 0 publication.

This type of recording sheet has good absorbability and fixability of water-based ink, but has a drawback that the ink receiving layer is poor in water resistance and the ink receiving layer is easily peeled off when exposed to water. Furthermore, when a filler such as silica is contained, when the content of the filler is high, the ink adsorption force is too strong, so that the appropriate spread of dots cannot be obtained, and the obtained image is The required image cannot be obtained due to the thin drawing lines. On the other hand, if the content of the filler is low, the ink may not be sufficiently dried, and blocking or image disorder may occur. Further, the addition of the filler may cause fine cracks on the surface of the recording sheet, resulting in lack of image clarity and deterioration of flexibility of the ink receiving layer.

A polyvinyl acetal resin such as polyvinyl phenyl aceto acetal having an acetalization degree of preferably about 5 to 20 mol% as a material having good water-based ink absorbability and fixability, a transparent ink receiving layer and good water resistance. Is proposed, for example, Japanese Patent Laid-Open No. 3-22
It is disclosed in Japanese Patent No. 1077. A recording material in which an ink receiving layer made of such a polyvinyl acetal resin is provided on a transparent support such as a polyester film is
It has good transparency and can be used for recording materials for overhead projectors.

However, it goes without saying that a support such as a polyester film or a metal, which does not easily adsorb water-soluble ink, is provided on the support such as paper with an ink receiving layer made of the above polyvinyl acetal resin. The recording material exhibits good performance when the amount of ink adhering per unit area is small, but when a large number of ink dots overlap, that is, when the amount of ink adsorbed per unit area is large, the ink receiving layer is sufficient for ink. I can't absorb it. Therefore, there is a problem that ink is accumulated between the ink receiving layer and the support, ink bleeding occurs, and the ink receiving layer is peeled off from the support. Such a problem is likely to occur even in the case of monochrome ink jet recording. Further, this is a problem that occurs not only when recording by the ink jet method but also when recording by the pen method or the like.

An ink jet recording sheet provided with an ink receiving layer containing polystyrene beads or hollow beads of a copolymer thereof as a filler has been proposed as an ink receiving layer having a high color density of ink and excellent in sharpness of printing. . For example, it is described in Japanese Patent Laid-Open No. 4-235086. Further, an inkjet recording sheet using a pigment containing a synthetic silica having a large surface area and a binder, or having an ink receiving layer containing a composition mainly composed of cationic colloid particles has been proposed. 7-2
5136 and Japanese Patent Application Laid-Open No. 7-17124. However, in a recording sheet in which polymer beads are contained as a filler in the ink receiving layer, the beads themselves do not have ink absorbability, so that a sufficient drying rate cannot be obtained or water resistance is not sufficient. there were.

[0011]

DISCLOSURE OF THE INVENTION The present invention provides a binder for an ink jet recording sheet, which is capable of forming an ink receiving layer having good ink absorbency, fixability and dryness, and good water resistance and heat blocking resistance. Is provided.

[0012]

In order to solve the above problems, the present inventors have found that nitrates of carboxyalkyl cellulose are useful as a binder, and have completed the present invention. . That is, the present invention provides nitric acid esters of carboxyalkyl cellulose having a degree of substitution of nitrate ester groups of 0.2 to 2.95 and a degree of substitution of carboxyalkyl ether groups of 0.05 to 2.8 per anhydrous glucose unit. The present invention relates to a binder for an inkjet recording sheet, which is characterized by containing.

The carboxyalkyl cellulose nitrate used in the present invention is defined as having a nitrate ester substitution degree contained in carboxyalkyl cellulose of 0.2 to 0.2.
2.95, the degree of carboxyalkyl ether group substitution is 0.
05 to 2.8, and specifically refers to the aqueous cellulose derivatives disclosed in JP-A-5-39301 and JP-A-5-39302. In the present invention, the degree of substitution of the nitrate ester group of the nitrate ester of carboxyalkyl cellulose is in the range of 0.2 to 2.95, and the preferred range is 0.2 or more and 2.2 or less. The ether group substitution degree is in the range of 0.05 to 2.8, and the preferable range is 0.05 or more and 1.5 or less. When the degree of substitution of the nitrate ester group is less than 0.2, the water resistance is insufficient, and when the degree of substitution of the carboxyalkyl ether group is less than 0.05, the solubility in water becomes insufficient and the ink absorbency becomes insufficient. Become. If the degree of substitution with the nitrate ester group exceeds 2.95, the hydrophilicity becomes insufficient. If the degree of carboxyalkyl ether group substitution exceeds 2.8, the water resistance of the coated surface will be insufficient.

The carboxyl groups contained in the nitrates of carboxyalkyl cellulose used in the present invention may be partially or completely neutralized. By neutralizing, the solubility in water and a water-soluble organic solvent containing water as a main component is increased, and the solubility is increased. To neutralize, 1 of cations such as alkali metal ions, alkaline earth metal ions, ammonium ions, organic amines, etc.
One kind or two or more kinds 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 organic solvent, but generally, it is contained. It is preferable that 50% or more of the carboxyl groups are neutralized.

An aqueous polymer may be mixed with the nitrate ester of carboxyalkyl cellulose used in the present invention for the purpose of improving the drying property of the ink, the film physical properties of the ink receiving layer, the gloss, the sharpness of the image and the like. , Is a good thing. In that case, the mixing ratio is preferably 97 to 30 parts by weight of the aqueous polymer with respect to 3 to 70 parts by weight of nitrates of carboxyalkyl cellulose in terms of solid content. The aqueous polymer used in the present invention can be dissolved or dispersed in water, a polar organic solvent or a mixed solvent thereof, and a resin having a film-forming property when mixed with the nitrate ester of carboxyalkyl cellulose in the present invention. Is.

Examples of the aqueous polymer used in the present invention include gelatin derivatives such as lime-processed gelatin, acid-processed gelatin and enzyme-processed gelatin, that is, anhydrides of dibasic acids such as phthalic acid, maleic acid and fumaric acid. Various gelatins such as reacted gelatin, starches such as oxidized starch, cationized starch and etherified starch, cellulose derivatives such as methylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, carboxymethylcellulose and hydroxyethylcellulose, polyalkylene oxides and the like. Derivatives of polyacrylic acid, polymethacrylic acid or esters thereof, salts and copolymers thereof, polyhydroxyethyl methacrylate and copolymers thereof, polyvinylpyrrolidone, polyvinyl chloride Pyridinium halides, various saponification degree of the polyvinyl alcohol,

Carboxy-modified, cation-modified and amphoteric polyvinyl alcohol, polyethylene glycol, polypropylene glycol, polyvinyl ether, alkyl vinyl ether / maleic anhydride copolymer, styrene /
Maleic anhydride copolymers and their salts, synthetic polymers such as polyethyleneimine, styrene / butadiene copolymers, conjugated diene copolymer latexes such as methylmethacrylate / butadiene copolymers, polyvinyl acetate, vinyl acetate -Maleic acid ester copolymer, vinyl acetate-acrylic acid ester copolymer, vinyl acetate copolymer latex such as ethylene-vinyl acetate copolymer, acrylic acid ester polymer, methacrylic acid ester polymer, ethylene-acrylic acid Acrylic polymer or copolymer latex such as ester copolymer, styrene / acrylic acid ester copolymer, vinylidene chloride copolymer latex or monomers containing functional groups such as carboxyl groups of these various polymers Functional group modified polymer latex, melamine resin , Water-based adhesives such as thermosetting synthetic resins such as urea resins, and synthetic resins such as polymethylmethacrylate, polyurethane resins, unsaturated polyester resins, vinyl chloride / vinyl acetate copolymers, polyvinyl butyral, and alkyd resins. it can. These can be used alone or in combination. Of these, cation-modified polyvinyl alcohol is particularly preferable.

Examples of the cation-modified polyvinyl alcohol which can be used in the present invention include polyvinyl alcohol having a cation-modified amount of 0.01 mol% or more. For example,
The cation-modifying group is selected from an amide group, an imide group, a primary amino group, a secondary amino group, a tertiary amino group, a primary ammonium salt group, a secondary ammonium salt group, a tertiary ammonium salt group, and a quaternary ammonium salt group. At least one cationic group may be mentioned, the inclusions of said groups being preferred. Further, a primary amino group, a secondary amino group, a primary ammonium base, and a secondary ammonium base are preferable, but especially 1
A primary amino group or a primary ammonium base is more preferred.

The amount of cation modification is preferably 0.1-30 mol%, more preferably 0.1-15 mol%.
If the modification amount of the cationic group is less than 0.01 mol%, the water resistance of the ink absorbing layer is insufficient, which is not preferable. The average degree of saponification is preferably 40-100 mol%. Saponification degree is 4
If it is less than 0 mol%, the ink absorbency is lowered, which is not preferable. The average degree of polymerization is preferably 100-5000, more preferably 200-3000. If the average degree of polymerization is less than 100, the water resistance of the ink absorbing layer will decrease, and
If it exceeds 000, the solution viscosity is too high, which is not preferable in terms of workability.

The water-soluble organic solvent used in the present invention comprises one kind or a combination of two or more kinds such as alcohols, polyhydric alcohols, derivatives of polyhydric alcohols, ketones, esters and carbonates. A solvent can be used. Alcohols include methanol, ethanol, n-propanol, n-butanol,
Examples thereof include n-pentanol, n-hexanol, n-heptanol, n-octanol, n-nonyl alcohol, n-decanol, n-undecanol, and isomers thereof, cyclopentanol, cyclohexanol, etc., preferably having 1 to 6 alkyl carbon atoms. It is an alcohol that has an individual.

As the polyhydric alcohols, ethylene glycol, propylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1, 2-cyclohexanediol, 1,7
-Heptanediol, 1,8-octanediol, 1,
9-nonanediol, 1,10-decanediol, glycerin, pentaerythritol and the like can be mentioned.

Derivatives of polyhydric alcohol include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monoisobutyl ether, propylene glycol monomethyl ether. , Propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, cellosolve acetate, etc., or solvent pocket books edited by the Society of Synthetic Organic Chemistry (p479 to p574), (September 20, 1990, Ohmsha) Examples thereof include the polyhydric alcohols and their derivatives.

Examples of ketones include acetone, methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, diisopropyl ketone, cyclopentanone and cyclohexanone. 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.

As ethers, diethyl ether,
Examples include isopropyl ether, n-butyl ether, tetrahydrofuran, tetrahydropyran, 1,4-dioxane and the like. Examples of the carbonates include dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate, ethylene carbonate and the like. The coating amount provided on the support is 0.1 to 50 g /
m ² , more preferably 0.5 to 25 g / m ² . If the coating amount is too small, the water absorption will be insufficient and it will take a long time to dry, or the color developability of the ink will be poor. Further, if the coating amount is too large, there are problems such as difficulty in coating and significant occurrence of curling in a low temperature and low humidity environment.

For forming these coating layers, known means such as an air knife coater, a blade coater, a bar coater, a gravure coater, a curtain coater, a roll coater and an applicator can be applied. At that time, it is preferable to apply a known surface treatment such as corona discharge treatment or primer treatment in air or other atmosphere to the support, if necessary, before coating, whereby good coatability is obtained. Not only can it be turned into a solid but also a strong coating layer can be formed on the surface of the support.

The support used in the present invention includes high-quality paper, medium-quality paper, art paper, bond paper, copy paper, baryta paper, cast-coated paper, corrugated paper, coated paper, synthetic paper, resin-coated paper, etc. Any of known materials such as paper, opaque film containing pigment, foam film, glass plate, cotton, rayon, cloth such as acrylic and polyester, and metal can be used. The support is appropriately selected from the above base materials according to the recording purpose of the recording medium, the use of the recorded image, or various conditions such as adhesion to the composition coated on the recording medium.

In the binder of the ink jet recording sheet used in the present invention, known additives such as calcium carbonate, basic magnesium carbonate, crystalline cellulose and other matting agents, and colloidal silica can be used as long as the characteristics of the present invention are not impaired. , Printing aids such as alumina sol, defoaming agents,
A coatability improver, a thickener, an antistatic agent, an antioxidant, an ultraviolet absorber, a dye, a water resistance agent, a light resistance improver, a preservability improver and the like can be appropriately added. By using the binder of the ink jet recording sheet containing the nitrate ester of carboxyalkyl cellulose of the present invention,
Good ink absorbency, fixability, and dryness, water resistance,
An ink jet recording sheet capable of forming an ink receiving layer having good heat blocking resistance is obtained.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be further described below with reference to examples. The method of measuring various characteristics in the present invention is as follows. [Drying property evaluation method] A solid print was made on a recording sheet, and after 60 seconds, a copy paper was overlaid on the printed portion and a load (125 g / c)
m ² ), and the degree of transfer to copy paper was evaluated. ○: No transfer △: Slightly transferred ×: Very transferred

[Evaluation Method of Heat-Resistant Blocking Property] The recording surfaces of the recording sheets are overlapped with each other, and the load (125 g / cm 2
The blocking state was determined after ² ) and standing still at 140 ° C. for 30 minutes. ◯: No resistance Δ: There was resistance X: There was peeling [Water resistance evaluation method] The printing original sheet with a solid print was immersed in water for 2 minutes and then naturally dried, and the ink flow condition was visually judged. ○: No change △: Slightly flowing ×: Spilled [Evaluation method of printability] Inkjet printer (BJ
-600 J; manufactured by Canon Inc.) was used to perform solid printing on a recording sheet, and the sharpness after recording and the degree of bleeding were visually determined. ○: good △: somewhat good ×: bad

(Production Example 1) 100 g of carboxymethyl cellulose (Serogen PL-15; manufactured by Daiichi Kogyo Seiyaku Co., Ltd .; carboxymethyl ether group substitution degree = 0.5) and sulfuric acid / nitric acid / water = 63/25/12 5,000 g of an acid mixture consisting of wt.% Was placed in a 5 liter reaction vessel,
The nitrification reaction is performed while continuing stirring at 10 ° C. for 60 minutes.
The reaction product is deoxidized with a centrifuge and immediately washed with a large amount of water. Furthermore, the reaction product is 10% in an autoclave.
It was made into a slurry and treated at 140 ° C. for 30 minutes, and then separated with a Buchner funnel to collect a reaction product. The reaction product was dried at 80 ° C. for 2 hours to obtain 129 g of carboxymethyl cellulose nitrate ester. The degree of substitution of the nitrate ester group per anhydrous glucose unit of the nitrate ester was 1.9 from the degree of substitution of the carboxymethyl ether group of carboxymethyl cellulose (0.5) and the measurement of the nitrogen content with a CHN coder. found.

Next, 100 g of nitrate ester of carboxymethyl cellulose having a degree of substitution of nitrate ester groups of 1.9 and a degree of substitution of carboxymethyl ether groups of 100 g of the anhydrous glucose unit thus obtained and ion-exchanged water 59.
8.6 g and 250 g of butyl cellosolve were put into a closed mixer and stirred. Further, 51.4 g of 10% ammonia water was added as a neutralizing agent and completely dissolved while heating to obtain a solution having a solid content of 10% (this is referred to as binder liquid A).

(Production Example 2) Carboxymethyl cellulose (Serogen 5A; manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd .; degree of carboxymethyl ether group substitution = 0.7) was used to prepare an acid mixture of sulfuric acid / nitric acid / water = 59/20 /. 90 g of dried nitric acid ester of carboxymethyl cellulose was obtained in the same manner as in Production Example 1 except that the content was 21% by weight and the treatment was carried out at 130 ° C. for 30 minutes in an autoclave. The degree of substitution of the nitrate ester group per anhydrous glucose unit of this nitrate ester is
It was found from the carboxymethyl ether group substitution degree (0.7) of carboxymethyl cellulose and the nitrogen content measured by a CHN coder that it was 1.2.

Next, 100 g of nitrate ester of carboxymethyl cellulose having a degree of substitution of nitrate ester group of 1.2 and a degree of substitution of carboxymethyl ether group of 0.7 obtained per anhydrous glucose unit and ion-exchanged water 84 were obtained.
2.8 g and 200 g of isopropyl alcohol were put into a closed mixer and stirred. 10% as a neutralizer
57.2 g of ammonia water was added and completely dissolved while heating to obtain a solution having a solid content of 10% (this is referred to as binder liquid B).

(Example 1) 200 g of polyvinyl alcohol (Gosefimer LL-02: manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) having a saponification degree of 40%, 700 g of methanol and 100 g of ion-exchanged water were put into a mixer and completely dissolved. Stirring was performed until a solid content of 20% was obtained (this is referred to as binder liquid C). The binder liquid A and the binder liquid C were mixed at a ratio shown in Table 1 in terms of weight ratio to prepare a coating liquid. The coating amount of the above coating solution after drying on copy paper is 10 to 1
It was coated with an applicator at 5 g / m ³ and dried to obtain a binder and a sheet for an inkjet recording sheet.

(Example 2) 60 g of polyvinyl alcohol having a saponification degree of 71 to 75% (Gosenol KP-06: manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) and 98 to 99% of polyvinyl alcohol (Gosenol NH-18: manufactured by Nippon Synthetic Chemical Industry) ) 40
g and ion-exchanged water 900 g were put in a mixer and stirred until completely dissolved to obtain a solution having a solid content of 10% (this is referred to as binder liquid D). An ink jet recording sheet binder and sheet were obtained in the same manner as in Example 1 except that the binder liquid C was changed to the binder liquid D.

(Example 3) 100 g of polyvinyl alcohol (Gosenol KP-06: manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) having a saponification degree of 71 to 75% and 900 g of ion-exchanged water were put in a mixer and stirred until completely dissolved. Done, solid content 10%
To obtain a solution (hereinafter referred to as a binder solution E). Example 1 except that the binder liquid C was changed to the binder liquid E
The same inkjet recording sheet binder and sheet were obtained.

Example 4 A binder and a sheet for an ink jet recording sheet were obtained in the same manner as in Example 1 except that the binder liquid A was changed to the binder liquid B. Example 5 A binder for an inkjet recording sheet and a sheet were obtained in the same manner as in Example 2 except that the binder liquid A was changed to the binder liquid B.

Example 6 A binder and a sheet for an ink jet recording sheet were obtained in the same manner as in Example 3 except that the binder liquid A was changed to the binder liquid B. (Example 7) Cation-modified polyvinyl alcohol (CM
318: Kuraray Co., Ltd.), 100 g of isopropyl alcohol, and 800 g of ion-exchanged water were put into a mixer and stirred until completely dissolved to obtain a solution having a solid content of 10% (this is referred to as a binder liquid F). The binder liquid A and the binder liquid F were mixed at a ratio shown in Table 1 in terms of weight ratio to prepare a coating liquid. The coating liquid was applied onto a copy paper with an applicator so that the coating amount after drying was 10 to 15 g / m ³ , and dried to obtain a binder and a sheet for an inkjet recording sheet.

Example 8 A binder and a sheet for an ink jet recording sheet were obtained in the same manner as in Example 7 except that the binder liquid A was changed to the binder liquid B. (Comparative Example 1) A binder and a sheet for an inkjet recording sheet were obtained in the same manner as in Example 1 except that only the binder liquid C of Example 1 was used as the binder liquid. (Comparative Example 2) A binder for an inkjet recording sheet and a sheet were obtained in the same manner as in Example 1 except that only the binder liquid D of Example 2 was used as the binder liquid.

Comparative Example 3 Example 3 as a binder liquid
A binder and a sheet for an inkjet recording sheet were obtained in the same manner as in Example 1 except that only the binder liquid E in Example 1 was used. (Comparative Example 4) A binder and a sheet for inkjet recording sheets were obtained in the same manner as in Example 1 except that only the binder liquid F of Example 7 was used as the binder liquid. (Comparative Example 5) The above evaluation was performed using a commercially available copy paper.

Table 1 shows the evaluation results of the above Examples 1 to 8 and Comparative Examples 1 to 5. In addition, the results of evaluation of ink drying property, heat blocking resistance, water resistance, and print quality are shown in order from the left in the table. From these results, it is understood that the binder of the present invention is excellent in ink absorbency, fixability, drying property, heat blocking property, and water resistance.

[0042]

[Table 1]

[0043]

The binder of the present invention has an ink absorbency,
Dryability, water resistance of the coated surface, and heat blocking resistance can be improved. Therefore, particularly when an inkjet printer using a water-based ink as a recording material is used, an inkjet recording sheet having good ink fixability can be obtained.
Further, since it has excellent compatibility with conventionally known binders, it can be used in combination with these.

Claims (6)

[Claims] 1. A nitrate ester of carboxyalkyl cellulose having a degree of substitution of a nitrate ester group of 0.2 to 2.95 and a degree of substitution of a carboxyalkyl ether group of 0.05 to 2.8 per anhydroglucose unit. A binder for an inkjet recording sheet, which comprises: 2. A binder for an inkjet recording sheet, which comprises 3 to 70 parts by weight of the nitrate ester of carboxyalkyl cellulose according to claim 1 and 97 to 30 parts by weight of an aqueous polymer. 3. A binder for an ink jet recording sheet, wherein the aqueous polymer according to claim 2 is a cation-modified polyvinyl alcohol. 4. A nitrate ester of carboxyalkyl cellulose having a degree of substitution of nitrate ester group of 0.2 to 2.95 and a degree of substitution of carboxyalkyl ether group of 0.05 to 2.8 per anhydroglucose unit. An ink jet recording sheet comprising: 5. An ink jet recording sheet comprising 3 to 70 parts by weight of the carboxyalkyl cellulose nitrate ester according to claim 4 and 97 to 30 parts by weight of an aqueous polymer. 6. An inkjet recording sheet, wherein the aqueous polymer according to claim 5 is a cation-modified polyvinyl alcohol.