JP3198173B2 - Inkjet recording sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording sheet, and more particularly to an ink jet recording sheet which prevents yellowing of the sheet with time, has a high print density, has a high ink absorption, and has excellent color. It is about a sheet.

[0002]

2. Description of the Related Art Ink-jet recording is a method in which minute droplets of ink are made to fly and adhere to a recording sheet such as paper according to various operating principles, thereby recording images and characters. It has features such as easy multi-coloring, great flexibility in recording patterns, and no need for development-fixing.
It is rapidly spreading in various uses as a recording device for various figures and color images including kanji. Furthermore, the image formed by the multi-color ink jet method is compared with the multi-color printing by the plate making method and the printing by the color photographic method,
It is possible to obtain comparable records. In addition, in applications where the number of copies required is small, it is being widely applied to the field of full-color image recording because it is cheaper than the photographic technique.

As recording sheets used in the ink jet recording system, efforts have been made in terms of apparatuses and ink compositions in order to use high-quality paper or coated paper used for ordinary printing and writing. However, with the improvement of the performance of ink jet recording apparatuses such as high-speed, high-definition and full-color apparatuses, and expansion of applications, more advanced characteristics are also required for recording sheets. That is, as the recording sheet, the density of the print dots is high, the color tone is bright and vivid, the ink does not flow out or bleeds even when the ink dots are quickly absorbed and the print dots overlap. High image reproducibility is required such that the diffusion in the direction is not unnecessarily large and the periphery is smooth and not blurred.

Several proposals have hitherto been made in response to such demands. For example, an ink-receiving layer serving as a void layer containing a silica-based pigment as a main component is provided on the surface of the support to improve the ink absorbency (JP-A-52-9074 and JP-A-58-72495). Gazette). In order to increase the ink absorption by this ink receiving layer and obtain print dots having high print dot density and no ink bleeding, JP-A-55-51583 and JP-A-56-157 disclose non-colloidal silica. There is a proposal to mix powder. Furthermore, focusing on the fact that the color and sharpness are in the distribution state of the dye in the ink in the ink receiving layer, a proposal has been made to use a specific agent that adsorbs the dye component (JP-A-55-144172). It has been done.

[0005] Further, since the preservability of the image after printing is required, in order to prevent color deterioration due to the change of the colorant in the ink due to ozone, sunlight, ultraviolet light, etc., cationic silica is used instead of highly active silica. Attempts have been made to use water-soluble aluminum oxides (for example, JP-A-60-232990, JP-A-2-198889). However, with the recent visualization, high resolution and high color are strongly demanded, and the inkjet recording apparatus has been changed to print many dots per unit area. The ink receiving layer composed of the above is also required to have high ink absorbency. However, when a silica-based pigment having high ink absorbency is applied to this requirement, there is a problem of the above-described color deterioration of the image. Therefore, the color deterioration of the image and the ink absorbability are contradictory characteristics. It has been designed without maximizing.

On the other hand, the problem of yellowing of the ink jet recording sheet over time cannot be ignored. The yellowing is a phenomenon in which the sheet is discolored to yellow or brown by some external influence. When yellowing occurs,
In addition to spoiling the aesthetics of the sheet, ink jet recording is designed to have a high whiteness for the color of the recording medium and is designed for color reproducibility. Become. In recent years, when an ink jet recording sheet after printing is stored, there are many occasions where the sheet is put in a bag made of polypropylene, polyvinyl chloride, polyethylene, or the like called a clear file or a clear book. Also, a plastic tape or paper tape coated with an adhesive may be used. However, these bags and tapes contain anti-static agents, flame retardants, coloring agents, foaming agents, cross-linking agents, lubricants, anti-softening agents, anti-aging agents, plasticizers, antioxidants, etc. For example, a phenolic compound used as an antioxidant causes yellowing. In particular, in the case of an ink jet recording sheet comprising an ink receiving layer containing a cationic hydrated aluminum oxide, yellowing is remarkable, and prevention of yellowing is the most important issue.

The ink jet recording sheet is adhered to or contacted with the above-mentioned bag or tape after or before recording, or stored with the above-mentioned bag or tape at a distance of about several mm to several cm without contact. Or they are kept. Therefore, when a phenolic compound frequently used as an antioxidant contained in the above-described bag or tape is adsorbed on an ink jet recording sheet by sublimation or the like, the adsorbed phenolic compound is subjected to an oxidation reaction or a radical reaction over time. For example, the quinone structure that develops yellow color is obtained, so that the yellow color changes with time. Since the yellow change caused by such a mechanism causes the color reproducibility of an image to be lost, prevention of yellow change is an important issue for an ink jet recording sheet characterized by good color reproducibility.

[0008]

SUMMARY OF THE INVENTION In view of the foregoing, an object of the present invention is to provide an ink jet recording sheet, and in particular, to prevent the yellowing of the sheet from changing over time, to provide a high print density, The present invention relates to an ink-jet recording sheet having a fast absorption and excellent color.

[0009]

Means for Solving the Problems The present inventors have conducted various studies on an ink jet recording sheet, and as a result,
It has been found that the object of the present invention can be achieved when a cationic hydrated aluminum oxide is contained in the ink receiving layer and starch particles are used as an essential component in combination. That is, the present invention is characterized in that, in an ink jet recording sheet provided with at least one or more ink receiving layers on a support, the ink receiving layer components are composed of cationic hydrated aluminum oxide and starch particles. To provide an ink jet recording sheet.

According to the present invention, starch particles are added to an ink-receiving layer of an ink-jet recording sheet containing a cationic hydrated aluminum oxide while taking advantage of the features of high print density, high ink absorption and excellent color. Ink-jet inks that suppress the yellowing of white paper (unprinted areas) of the ink-jet recording sheet, which is a drawback, have higher print density, faster ink absorption, and improved image color A recording sheet can be obtained.

Examples of the hydrated aluminum oxide include gibbsite obtained by the Bayer method, vialite obtained by blowing carbon dioxide gas into an alkali aluminate solution, trihydrate of nostradite or an aluminum salt and alkali,
Amorphous alumina gel obtained by precipitation from alkali aluminate and acid, hydrolysis from aluminum amalgam, hydrolysis of aluminum alkoxide, etc.
There are boehmite obtained by hydrothermally treating a hydrate or amorphous alumina gel, and monohydrate of boehmite gel (pseudo boehmite) formed by aging amorphous alumina gel at 25 ° C. or more in an aqueous solution.

The cationic hydrated aluminum oxide according to the present invention refers to any of the above-mentioned hydrated aluminum oxides whose surface charge exhibits cationicity when dispersed in water. Furthermore, the cationic hydrated aluminum oxide according to the present invention includes a gel-like substance such as an amorphous alumina gel or a boehmite gel (pseudo-boehmite) which expresses its structural viscosity by itself, and salts from these gel-like substances. It also includes those that have been removed, dried into blocks, pulverized, or powdered by spray drying and classified. The cationic hydrated aluminum oxide obtained by these methods creates a porous structure with a pore diameter of 50-5000 Å. In the present invention, by forming the coating composition of the ink receiving layer with the hydrated aluminum oxide, when the coating composition is applied and dried, the ink receiving layer is almost free of moisture, It becomes an irreversible porous solid exhibiting cationicity.

The starch particles according to the present invention are produced from raw materials such as corn (corn starch), wheat, barley, rice, potato (potato), cassava (tapioca), sweet potato (sweet potato) and sago. Further, oxidized starch obtained by oxidizing these raw materials with an oxidizing agent such as sodium hypochlorite, acid-treated starch treated with hydrochloric acid or sulfuric acid, enzyme-treated starch, and diacid reacted with periodic acid. Esterified starch such as aldehyde starch, acetylated starch, urea phosphorylated starch, phosphorylated starch, hydroxyalkylated starch, etherified starch such as carboxyalkylated starch, cationized starch, formaldehyde crosslinked starch, epichlorohydrin crosslinked starch, phosphoric acid crosslinked Crosslinked starch such as starch, acrylic acid,
Vinyl monomers and epoxides such as acrylonitrile, acrylamide, methacrylate, vinyl acetate,
Modified starch particles such as graft-polymerized starch obtained by polymerizing cyclic monomers such as episulfide, imine, and lactam into starch having active sites are also included.

Among these starch particles, those having little or no solubility in cold water are preferred in the present invention.
The water is almost insoluble in water below 100 ° C and the gelatinization start temperature is 50
It is desirable that the temperature is not less than ° C. Further, the temperature of the coating liquid at the time of preparation and coating is desirably less than 50 ° C. If the temperature of the coating liquid during the preparation and application is higher than the gelatinization temperature, the starch particles cannot maintain the original particle shape and are gelatinized inside the particles. If the coating liquid is thickened, the coating cannot be performed, or even if the coating can be performed, the object cannot be achieved because the particle shape is not maintained on the recording sheet. In the present invention, the starch particles must remain in the recording sheet while maintaining the particle shape.

The particle size of the starch particles is not particularly limited,
The volume average particle diameter is preferably in the range of 1 to 20 μm. If the particle diameter is too small, the porosity and amount of porosity between the particles will decrease, and the ink absorption speed and absorption capacity will decrease. In multi-color printing, if the amount of ink is large, ink overflows on the recording sheet surface, and the quality of the recorded image tends to be significantly reduced. Conversely, if the particle diameter is too large, the surface roughness of the recording sheet surface becomes too coarse, feathering occurs, the recording dot shape deteriorates,
The quality of the recorded image tends to be significantly reduced. Therefore, it is necessary to select a starch particle having a desired particle size such as selection of a starch variety, classification treatment, and pulverization treatment in accordance with the ink droplet diameter, recording density, and the like. The average particle size of the starch particles (unprocessed, unclassified and pulverized) produced from the starch raw material is, for example, an average of 15 μm (about 6 to 25 μm) for corn starch,
In wheat starch, the average small grain is 6 μm and the large grain is 25 μm (2-
Rice starch average 5 μm (about 1 to 10 μm), potato starch average 40 μm (about 2 to 100 μm), tapioca starch average 20 μm (about 4 to 35 μm), sago starch average 30 μm (about 10 to 65 μm). .

[0016] The starch particles usually maintain an equilibrium state by holding about 12 to 17% of water in the atmosphere. When water is absorbed, it swells, and when it is dehydrated, it shrinks and the particle size changes.
Further, since the starch particles have a fine porous structure, they generally reversibly absorb and dehydrate about 40 to 60% of water. Rice starch, in this, absorbs 78-80% of water.
Some modified starch particles exhibit a higher water absorption.
The properties and the like of these starches are also described in the “Starch Science Handbook” (July 20, 1977, published by Asakura Shoten, supervised by Jiro Nikuni).

The support according to the present invention includes LBKP, NB
Chemical pulp such as KP, GP, PGW, RMP, TMP,
Mechanical pulp such as CTMP, CMP, CGP, etc., wood pulp such as waste paper pulp such as DIP, etc., and conventionally known pigments as main components, and binders, sizing agents, fixing agents, retention agents, cationizing agents, paper strength agents And other additives are mixed by using one or more of them, and the base paper manufactured by various apparatuses such as fourdrinier paper machine, round paper machine, twin wire paper machine, etc. Also included are base paper provided with a press or anchor coat layer, and coated paper such as art paper, coated paper, cast coated paper, etc. provided with a coat layer thereon. Such a base paper and a coated paper may be provided with an ink receiving layer as it is, or may be a machine calendar, a TG calendar,
A calendar device such as a soft calendar may be used.

As the support, a polyolefin resin layer may be provided on the above-mentioned base paper,
Polypropylene, polyester, nylon, rayon,
It also includes a film material of a synthetic resin such as polyurethane or a mixture thereof, and a sheet formed by forming the synthetic resin into fibers.

Although the ink receiving layer of the present invention is composed of the hydrated aluminum oxide, other pigments may be used in combination depending on the use of the ink jet recording sheet and the characteristics according to the requirements. Further, a back coat layer may be provided as necessary. As the pigment applicable to the ink receiving layer, the back coat layer, and the support, one or more known white pigments can be used. For example, light calcium carbonate, heavy calcium carbonate, kaolin, talc, calcium sulfate,
Barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, satin white, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate, synthetic amorphous silica, colloidal silica, colloidal alumina, pseudoboehmite, aluminum hydroxide, alumina , Lithopone, zeolite, hydrohaloysite, magnesium carbonate, white inorganic pigments such as magnesium hydroxide, styrene-based plastic pigments, acrylic-based plastic pigments,
Organic pigments such as polyethylene, microcapsules, urea resins, melamine resins and the like can be mentioned.

The ink receiving layer of the present invention has a dry coating amount of 1
If it is 0 g / m ² or less, a part of the starch particles is gelatinized without a binder to develop strength, but depending on the application, if necessary, polyvinyl alcohol, vinyl acetate, oxidized starch, Cellulose derivatives such as etherified starch, carboxymethylcellulose, and hydroxyethylcellulose; water-soluble polymer binders such as casein, gelatin, soybean protein, and silyl-modified polyvinyl alcohol; maleic anhydride resin, styrene-butadiene copolymer, and methyl methacrylate-butadiene Conjugated diene-based copolymer latex such as polymer; Acrylic ester and methacrylic acid ester polymer or copolymer; Acrylic acid and methacrylic acid polymer or copolymer-based acrylic polymer latex; Ethylene vinyl acetate Vinyl polymer latex such as copolymer; Or a functional group-modified polymer latex of a functional group-containing monomer such as a carboxyl group of these various polymers; an aqueous adhesive such as a thermosetting synthetic resin such as a melamine resin or a urea resin; a polymethyl methacrylate or a polyurethane resin , Unsaturated polyester resin, vinyl chloride
Synthetic resin-based adhesives such as vinyl acetate copolymer, polyvinyl butyral, and alkyd resin can be used, and one or more kinds can be used, and these binders may be applied to the back coat layer.

In the ink receiving layer, other additives such as a pigment dispersant, a thickener, a dye fixing agent, a fluidity improver, an antifoaming agent, a foam inhibitor, a release agent, a foaming agent, As necessary, a penetrant, a coloring dye, a coloring pigment, a fluorescent whitening agent, an ultraviolet absorber, an antioxidant, an antiseptic, an antibacterial agent, a waterproofing agent, a wet paper strength enhancer, a dry paper strength enhancer, and the like are appropriately compounded. These may be applied to the back coat layer.

Methods for coating and impregnating the ink receiving layer and the back coat layer include various blade coaters, roll coaters,
Various devices such as an air knife coater, bar coater, rod blade coater, curtain coater, short dwell coater, and size press can be used on-machine or off-machine. After coating or impregnation, machine calendar, TG calendar, super calendar,
The finishing may be performed using a calendar such as a soft calendar.

The aqueous ink referred to in the present invention is a recording liquid comprising a colorant, a liquid medium, and other additives. Examples of the coloring agent include conventionally known water-soluble dyes such as direct dyes, acid dyes, basic dyes, reactive dyes, and food dyes.

Examples of the solvent for the aqueous ink include water and various water-soluble organic solvents such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, C1-C4 alkyl alcohols such as isobutyl alcohol; amides such as dimethylformamide and dimethylacetamide; ketones or ketone alcohols such as acetone and diacetone alcohol; ethers such as tetrahydrofuran and dioxane; polyethylene glycol and polypropylene glycol Polyalkylene glycols such as ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, Alkylene glycols having 2 to 6 alkylene groups such as lene glycol and diethylene glycol; lower alkyl ethers of polyhydric alcohols such as glycerin, ethylene glycol methyl ether, diethylene glycol methyl (or ethyl) ether and triethylene glycol monomethyl ether; No. Among these many water-soluble organic solvents, polyhydric alcohols such as diethylene glycol and lower alkyl ethers of polyhydric alcohols such as triethylene glycol monomethyl ether and triethylene glycol monoethyl ether are preferred. Other additives include, for example, P
Examples include an H regulator, a metal sequestering agent, a fungicide, a viscosity modifier, a surface tension regulator, a wetting agent, a surfactant, and a rust inhibitor.

The ink-jet recording sheet of the present invention is not limited to use as an ink-jet recording sheet, but may be used as any recording sheet using a liquid ink at the time of recording. For example, a heat-fusible substance, a heat-fusible ink containing a dye or pigment as a main component, applied on a thin support such as a resin film, high-density paper, or synthetic paper, is heated from the back surface, and the ink is heated. An image-receiving sheet for thermal transfer recording, which is melted and transferred, an ink-jet recording sheet, which heats and melts a hot-melt ink to form fine droplets, and performs flight recording, an ink-jet recording sheet using an ink in which an oil-soluble dye is dissolved in a solvent, photopolymerization And an image receiving sheet corresponding to a photosensitive pressure-sensitive donor sheet using microcapsules containing a type monomer and a colorless or colored dye / pigment.

A common feature of these recording sheets is that the ink is in a liquid state at the time of recording. The liquid ink permeates or spreads in the depth direction or the horizontal direction of the ink receiving layer of the recording sheet until it hardens, solidifies or fixes. The above-described various recording sheets require absorptivity according to each system, and the inkjet recording sheet of the present invention may be used as the above-described various recording sheets. Further, the ink jet recording sheet of the present invention may be used as a recording sheet for heating and fixing an electrophotographic recording type toner widely used in copying machines, printers and the like.

[0027]

According to the present invention, by applying starch particles as an essential component to an ink receiving layer containing a cationic hydrated aluminum oxide, yellowing is suppressed, printing density is high, and good color is obtained. An ink jet recording sheet can be obtained. While containing the hydrated aluminum oxide is characterized by little color degradation of the image after printing,
Due to the adsorption of the antioxidant contained in the bag or the tape by sublimation or the like, yellowing with time becomes a problem. Unless starch particles are added, the yellowing of the sheet cannot be suppressed. Although the action of the starch particles in the present invention is not clear, the following is presumed.

The starch particles are dispersed in water in the coating composition in the ink receiving layer, and are fixed during drying after coating or impregnation. Therefore, in the drying process, part of the starch particles is gelatinized under the influence of the water contained in the coating composition and the water contained in the starch particles, and is considered to function as a binder by forming a film. In fact, in a region where the coating amount of the ink receiving layer is small, an ink receiving layer having sufficient adhesive strength can be obtained only with the starch particles. Due to the formation of the starch particles into a film, the surface of the hydrated aluminum oxide is covered, and in order to reduce the above-mentioned compound causing the yellow change from penetrating and adsorbing to the ink receiving layer, a problem of yellow change is caused. Is considered to be suppressed.

It seems that the formation of the starch particles into a film reduces the voids in the ink receiving layer and hinders ink penetration. However, since the starch particles have a filmed portion and a porous portion, the starch particles have It is considered that the print density can be improved by holding the ink in the ink receiving layer so that the porous portion improves the ink absorbency.
Furthermore, since the hydrated aluminum oxide has a cationic property, in addition to improving the fixability of the ink by an electrical reaction with the anionic ink, the porous hydrated aluminum oxide has Since the voids increase, the effect of the present invention can be further enhanced.

On the other hand, when the starch particles are treated at a high temperature to completely gelatinize or blend with another water-soluble polymer binder, the yellowing is improved, but the pores of the ink receiving layer are closed, so that the ink receiving layer is closed. This causes a problem that the dot diameter is enlarged, the dots are enlarged, and the dots are rubbed in the ink jet recording apparatus to stain a non-image area called background stain. However, even in such a case, by blending the starch particles, the problems of enlargement of the dot diameter and background contamination can be reduced.

The weight ratio (W) of the hydrated aluminum oxide W _A and the starch particles W _S applied to the ink receiving layer according to the present invention.
_A / W _S ) is 1/10 to 10/1, preferably 1/1.
If the ratio is 0 to 2/1 and is less than 1/10, the print density is reduced to deteriorate the color, and furthermore, the penetration of the printed ink is slowed and the ink is diffused in the surface direction of the ink receiving layer. As a result, the dot diameter becomes large and the problem of background contamination occurs. If it exceeds 10/1, the effect of the starch particles on yellowing becomes difficult to be obtained.

[0032]

EXAMPLES The present invention will be described below with reference to examples of the present invention, but the present invention is not limited to these examples.
Further, "parts" and "%" shown in Examples are parts by weight and% by weight unless otherwise specified.

Example 1 A support was made of light calcium carbonate / heavy calcium carbonate / talc with respect to 100 parts of wood pulp composed of 80 parts of LBKP (freeness of 400 mlcsf) and 20 parts of NBKP (freeness of 450 mlcsf). 25 parts of a pigment having a ratio of 30/35/35, 0.10 parts of a commercially available alkyl ketene dimer,
After preparing 0.03 part of a commercially available cationic (meth) acrylamide, 0.8 part of a commercially available cationized starch, and 0.4 part of a sulfuric acid band, papermaking was performed using a fourdrinier paper machine at a basis weight of 90 g / m ² .

The ink receiving layer was provided on the surface of the support.
The coating composition of the ink receiving layer is composed of 50 parts of xerogel (porous cationic hydrated aluminum oxide) having an average secondary particle diameter of 4 μm prepared from alumina hydrogel, and starch particles that are not gelatinized (rice starch; micropearl) : Shimada Chemical Industry Co., Ltd.). The coating composition was solidified at a solid content of 13%, and coated and dried with an air knife coater to a dry coating amount of 5 g / m ^2, and then calendered under the same conditions as in Example 1, An ink jet recording sheet of Example 1 was obtained.

Example 2 A support was obtained in the same manner as in Example 1. The coating composition for the ink receiving layer was 100 parts of the same cationic hydrated aluminum oxide as in Example 1, and 50 parts of the same starch particles as in Example 1 without gelatinization. The solid content concentration of the coating composition is 13%
The amount of dry coating was 5 g /
After coating and drying so as to obtain m ² , a calendar treatment was performed under the same conditions as in Example 1 to obtain an ink jet recording sheet of Example 2.

Example 3 A support was obtained in the same manner as in Example 1. The coating composition of the ink receiving layer is a cationic hydrated aluminum oxide (Cat
aluminum AS-1 (produced by Catalyst Chemical Industry Co., Ltd.)
0 parts, and 50 parts of the same starch particles as in Example 1 without gelatinization. The coating composition was solidified at a solid content of 13%, and coated and dried with an air knife coater to a dry coating amount of 5 g / m ^2, and then calendered under the same conditions as in Example 1, An ink jet recording sheet of Example 3 was obtained.

Example 4 A support was obtained in the same manner as in Example 1. The coating composition of the ink receiving layer is a cationic hydrated aluminum oxide (Cat
aluminum AS-2 (produced by Catalyst Chemical Industry Co., Ltd.)
0 parts, and 50 parts of the same starch particles as in Example 1 without gelatinization. The coating composition was solidified at a solid content of 13%, and coated and dried with an air knife coater to a dry coating amount of 5 g / m ^2, and then calendered under the same conditions as in Example 1, An ink jet recording sheet of Example 4 was obtained.

Example 5 A support was obtained in the same manner as in Example 1. The coating composition of the ink receiving layer is a cationic hydrated aluminum oxide (Cat
aluminum AS-3: manufactured by Catalyst Kasei Kogyo Co., Ltd.)
0 parts, and 50 parts of the same starch particles as in Example 1 without gelatinization. The coating composition was solidified at a solid content of 13%, and coated and dried with an air knife coater to a dry coating amount of 5 g / m ^2, and then calendered under the same conditions as in Example 1, An ink jet recording sheet of Example 5 was obtained.

Comparative Example 1 A support was obtained in the same manner as in Example 1. The coating composition of the ink receiving layer was 100 parts of the same cationic hydrated aluminum oxide as in Example 1, and 50 parts of the same starch particles as in Example 1 dispersed in water and gelatinized by heat treatment. . The coating composition was adjusted to a solid content of 10% by an air knife coater so that the dry coating amount was 5 g / m ^2.
After drying, a calender treatment was performed under the same conditions as in Example 1,
An ink jet recording sheet of Comparative Example 1 was obtained.

Comparative Example 2 A support was obtained in the same manner as in Example 1. The coating composition of the ink receiving layer was composed of 100 parts of the same cationic hydrated aluminum oxide as in Example 1 and polyvinyl alcohol (PVA11).
7: manufactured by Kuraray Co., Ltd.). After the solid content concentration of the coating composition was set to 10%, application and drying were performed with an air knife coater so that the dry coating amount was 5 g / m ² .
A calendar process was performed under the same conditions as in Example 1, and Comparative Example 2 was performed.
Was obtained.

Comparative Example 3 A support was obtained in the same manner as in Example 1. The coating composition of the ink receiving layer was composed of 100 parts of the same cationic hydrated aluminum oxide as in Example 1 and polyvinyl alcohol (PVA11).
7: manufactured by Kuraray Co., Ltd.). After the solid content concentration of the coating composition was set to 10%, application and drying were performed with an air knife coater so that the dry coating amount was 5 g / m ² .
A calendar process was performed under the same conditions as in Example 1, and Comparative Example 2 was performed.
Was obtained.

Table 1 shows the evaluation results of Examples 1 to 5 and Comparative Examples 1 to 3. Yellow change, print density, which is the object of the present invention,
The ink absorption was evaluated by the following method.

<Yellow change>4,4'-Methylene-bis (2,6-di-t-
A few drops of an IPA (isopropyl alcohol) solution in which 1% of butyl phenol) was dissolved was dropped with a pipette, and absorbed on the ink receiving layer surface of each sample. Then, it was put in a commercially available polypropylene film and left indoors for one week. Using a color difference meter (CR-100: manufactured by Minolta Camera Co., Ltd.), the chromaticity b ^* (C
(IE 1976 compliant) absolute value Δb ^* was measured. △
When b ^* exceeds 10, it indicates that the ink jet recording sheet has a problem of yellowing.

<Print Density> A black ink was printed by an ink jet printer (IO-720: manufactured by Sharp Corporation), and the print density was measured by optical density.
A method with a higher numerical value indicates that the print density is higher.

<Ink Absorbency> After printing a multicolor dot composed of four inks of cyan ink, magenta ink, yellow ink, and black ink, immediately press white paper against the printing surface to transfer the ink transferred to the white paper. The state was visually determined according to the following criteria. Acceptable levels are A and B. A: Transfer of ink was not confirmed, and ink absorbability was good. B: Transfer of the ink was slightly confirmed, but it did not lead to enlargement of the dot diameter or background contamination. C: The transfer of the ink is on the entire surface of the white paper, and the dot diameter is enlarged and the background becomes dirty.

[0046]

[Table 1]

[0047]

As is apparent from the above, by applying non-gelatinized starch particles to the ink receiving layer containing the cationic hydrated aluminum oxide, yellowing,
An ink jet recording sheet having excellent print density and ink absorbability can be obtained. On the other hand, when gelatinized starch or another water-soluble binder is used as a substitute, the ink absorbency decreases, and when the amount of application is reduced to improve it, yellowing worsens. However, it can be seen that the printing density is high due to the non-gelatinized starch particles. That is, according to the present invention, the yellowing of the sheet over time is prevented, and
It is possible to obtain an ink jet recording sheet having high print density, quick ink absorption, and excellent color.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-277481 (JP, A) JP-A-60-232990 (JP, A) JP-A-55-51583 (JP, A) JP-A-62 158084 (JP, A) JP-A-5-169789 (JP, A) JP-A-5-124330 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41M 5/00 B41J 2 / 01

Claims (1)

(57) [Claims] 1. An ink jet recording sheet provided with at least one or more ink receiving layers on a support,
An ink jet recording sheet wherein the ink receiving layer component comprises a cationic hydrated aluminum oxide and starch particles.