JPH08118791A - Ink jet recording sheet and manufacture thereof - Google Patents

Abstract

PURPOSE: To provide an ink jet recording sheet which has the high printing density of a recorded image or character, excellent ink absorptivity and in which the yellowing of a white part is remarkably reduced and a method for manufacturing the same. CONSTITUTION: An ink receiving layer provided on a support is formed of inorganic pigment having BET specific surface area of 100m<2> /g or more and adhesive, and phosphorus antioxidant is carried in the layer. Preferably, the antioxidant has at least one or more of phosphorous acid structures in which a functional group of alkoxy group or substituted alkoxy group is located adjacent to a phosphorus atom.

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 for recording with an ink and a method for producing the same, and in particular, it has a high print density of images and characters recorded on the ink jet recording sheet, The present invention relates to an inkjet recording sheet which maintains the feature of being excellent in absorptivity and remarkably reduces yellowing of a white paper portion which is a drawback of the conventional coat type inkjet recording sheet, and a manufacturing method thereof.

[0002]

2. Description of the Related Art The ink jet recording system is a system in which minute droplets of ink are ejected by various operating principles and adhered to a recording sheet such as paper to record images, characters, etc., but high speed and low noise. , Easy to multicolor, great flexibility of recording pattern, no need for development-fixing,
As a recording device for various figures and color images including kanji, it is rapidly spreading in various applications. Furthermore, the image formed by the multicolor ink jet system is
It is possible to obtain a comparable record. Further, in applications requiring a small number of copies, it is being widely applied to the full-color image recording field because it is cheaper than the photographic technique.

As a recording sheet used in this ink jet recording system, efforts have been made from the viewpoint of the apparatus and the ink composition in order to use high-quality paper or coated paper which is used for ordinary printing and writing. However, as the performance of inkjet recording apparatuses has been improved and the applications have been expanded, such as high-speed, high-definition or full-color apparatus, the recording sheets are required to have higher characteristics. That is, as the recording sheet, the density of print dots is high, the color tone is bright and vivid, the ink does not flow out or bleed even when the print dots overlap due to fast ink absorption, and the print dots The lateral spread of the ink does not become larger than necessary, the shape of the ink dots is close to a perfect circle, the periphery is smooth and does not blur, the whiteness of the recording sheet is high, and the contrast with the ink dots is large, etc. Needs to be satisfied.

Conventionally, in order to satisfy these conditions,
It has been proposed to apply various inorganic pigments to the surface of the paper together with an adhesive, if necessary, or to fill the inside. For example, synthetic amorphous silica and / or a salt thereof is used as the inorganic pigment (JP-A-57). No. 157786) and containing a porous cationic hydrated aluminum oxide (JP-A-60-232990). Among these, JP-A-60-204390 and As described in JP-A-2-198889, B
A recording sheet containing a synthetic hydrated aluminum oxide which is a synthetic amorphous silica having a large ET specific surface area or a cationic colloidal particle has an advantage that the printing density is particularly high and the ink absorbency and the color developability are excellent. There is.

However, such an ink jet recording sheet containing an inorganic pigment having a high specific surface area is stored in a file made of polyethylene, polypropylene, vinyl chloride resin or the like, or is stored on a tape, a glue, a platen rubber roll of a printer or the like for a long time. When they are brought into contact with each other, there is a problem in that the white portion of the inkjet recording sheet causes yellowing and the appearance is significantly impaired. In addition, in order to improve water resistance of printed images and characters, a cationic dye fixing agent is usually added together with an inorganic pigment to such an ink jet recording sheet, but such a cationic dye fixing agent is added. It is known that the cause of this is not clear, but the yellowing of the white paper portion of the inkjet recording sheet is further aggravated.

The reason why the white paper portion of the ink jet recording sheet turns yellow in this way is that the ratio of the antioxidant contained in the file such as polyethylene or polypropylene, the tape adhesive, the glue, the rubber or the like to form the ink receiving layer is high. It is thought that this is because the inorganic pigment having a surface area is volatilized and adsorbed, and is oxidized on the inkjet recording sheet. Many polypropylenes, polyethylenes, and the like are kneaded with an antioxidant having a phenol group in the molecule, such as butylhydroxytoluene (hereinafter abbreviated as BHT), and these phenolic antioxidants are oxidized to give quinone. It is well known that the structure makes it yellow.

In order to avoid such a problem, in JP-A-1-115677, a recording sheet having both a synthetic silica having a specific surface area of 100 m ² / g or more by a BET method and a thioether antioxidant is disclosed in JP-A-1-115677. JP-A 1-218882 discloses a recording sheet in which the surface coat layer contains a synthetic amorphous silica having a BET specific surface area of 10 to ²⁰⁰ m ² / g, which is surface-treated with an aluminum compound, and JP-A-5-221115 discloses an ink receiving layer. As described above, a recording sheet containing starch particles or modified starch particles thereof and ethylene vinyl acetate copolymer resin or a cationic dye fixing agent in combination is required for the inkjet recording sheet as described above. It satisfies various characteristics and suppresses the yellowing problem of the blank part of the recording sheet.

However, with the recording sheet as described above, while satisfying various characteristics required of the ink jet recording sheet such as sufficient print density and ink absorbability, the yellowing of the white paper portion of the recording sheet is completely eliminated. It was difficult to avoid.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to further improve the conventional technique in the above technical field. In particular, in the present invention, a white paper of an inkjet recording sheet containing an inorganic pigment having a high specific surface area, which gives a high print density, excellent ink absorbability and color development, but easily causes yellowing of a white paper portion when stored in a file etc. This is to prevent yellowing of the parts.

[0010]

Means for Solving the Problems As a result of intensive investigations to solve the above problems, the present inventors have found that a phosphorus-based antioxidant is contained in an ink receiving layer composed of an inorganic pigment having a high specific surface area and an adhesive. It was found that the object of the present invention is satisfied only in a coat type ink jet recording sheet carrying the above, and the inventors have invented the ink jet recording sheet of the present invention and the manufacturing method thereof.

That is, the ink jet recording sheet of the present invention is an ink jet recording sheet in which an ink receiving layer is provided on a support, and the ink receiving layer composition mainly comprises an inorganic pigment having a BET specific surface area of 100 m ² / g or more and an adhesive. And a phosphorus-based antioxidant is carried in the ink receiving layer.

In the ink jet recording sheet of the present invention, preferably, the phosphorus antioxidant has at least one phosphorous acid structure in which a functional group which is an alkoxy group or a substituted alkoxy group is adjacent to a phosphorus atom. Characterize.

The phosphorus-based antioxidant is added in an amount of 0.1 to 20 parts by weight based on 100 parts by weight of the inorganic pigment in the ink receiving layer.
It is preferably 0 part by weight.

In the ink jet recording sheet of the present invention, the inorganic pigment is at least one kind selected from synthetic amorphous silica and cationic colloid particles.

Further, it is preferable that the ink receiving layer composition contains a cationic dye fixing agent.

The method for producing an ink jet recording sheet of the present invention is the same as the method for producing an ink jet recording sheet in which an ink receiving layer is provided on a support, and an inorganic pigment mainly having a BET specific surface area of 100 m ² / g or more is provided on the support. And the ink-receiving layer coating liquid comprising an adhesive to form the ink-receiving layer, and the phosphorus-based antioxidant solution or its emulsion is coated on the ink-receiving layer to form the ink-receiving layer. It is characterized in that it is impregnated and carried therein.

Furthermore, the method for producing an ink jet recording sheet of the present invention is mainly the method for producing an ink jet recording sheet in which an ink receiving layer is provided on a support.
A phosphorus-based antioxidant or its emulsion is mixed in an ink-receiving layer composition composed of an inorganic pigment and an adhesive having a T specific surface area of 100 m ² / g or more to prepare an ink-receiving layer coating liquid, and the ink-receiving layer coating liquid is prepared. A liquid is applied onto the support to form the ink receiving layer, and the phosphorus-based antioxidant is supported in the ink receiving layer.

The ink jet recording sheet of the present invention and the method for producing the same will be described below in detail. The use of a phosphorus-based antioxidant to enhance the yellowing prevention effect of an inkjet recording sheet is disclosed in JP-A-61-41584, but the phosphorus-based antioxidant disclosed in the publication is used. Since the ink jet recording sheet is a transparent recording sheet, it is essential that the agent be used in combination with a highly transparent polyurethane resin, especially when exposed to an optical device such as a slide or an OHP (overhead projector).
It is added to prevent yellowing of the polyurethane resin itself on the recording surface caused by photooxidation. On the other hand, as described above, the phosphorus-based antioxidant in the ink jet recording sheet of the present invention is used for storing the recording sheet in a file made of polyethylene, polypropylene, vinyl chloride resin or the like, tape, glue, and platen rubber roll of a printer. It is added in order to prevent yellowing of the phenolic antioxidant itself such as BHT, which is generated by being adsorbed and oxidized by an inorganic pigment having a high adsorbing ability from these when it is brought into contact with etc. for a long time. Therefore, the expression mechanism is obviously different.

In order to investigate the degree of yellowing of the blank portion of the ink jet recording sheet, the present inventors have examined the BHT dimer (4,4'-methylenebis-2, 6-di-t-butylphenol) alcohol (ethanol, isopropyl alcohol, etc.) 1
% Solution is spotted on the ink jet recording sheet so as to have a solid content of 0.5 g / m ^2, and naturally dried.
After left for 3 days at 65 ° C. and 65% RH, L ^* a ^* b ^* (a colorimetric method according to CIE) before and after the standing was measured with a color difference meter (CR100: manufactured by Minolta). And
The difference in b ^* before and after processing (△ b ^* )
Was evaluated. It should be noted that the smaller this value is, the smaller the yellowing change is, and Δb ^* is preferably 15 or less, and when 10 or less, there is no problem in practical use and it is particularly preferable. The tendency of this measurement result almost coincided with the degree of yellowing of the white paper portion that occurred when actually storing it in a file or the like.

In the ink jet recording sheet of the present invention, the Δb ^* value measured by the above method is 15 or less, and the yellowing of the white paper portion of the recording sheet can be significantly suppressed. When the ink-receiving layer composition does not carry a phosphorus-based antioxidant and contains only the inorganic pigment and the adhesive, the white paper portion of the recording sheet easily turns yellow, and the Δb ^* value measured by the above method exceeds 15. Therefore, when a phenolic antioxidant other than phosphorus, for example, a phenolic antioxidant such as BHT is used, the yellowing of the blank portion of the recording sheet is adversely promoted due to the above-mentioned reasons. The Δb ^* value measured by the above method exceeds 30, which is not preferable.

The phosphorus-based antioxidant contained in the ink receiving layer in the present invention may be any conventionally known phosphorus-based antioxidant, for example, triphenylphosphite, triethylphosphite, tris (2-ethylhexyl). Phosphite, tridecyl phosphite,
Tristearyl phosphite, Tris (tridecyl)
Phosphite, diphenylmono (2-ethylhexyl) phosphite, diphenylmonodecylphosphite, diphenylisodecylphosphite, diphenylmonotridecylphosphite, tris (nonylphenyl) phosphite, diphenylnonylphosphite, trilauryltrithiophosphite , Tetraphenyl dipropylene glycol diphosphite, tetraphenyl tetra (tridecyl) pentaerythritol tetraphosphite, tetra (tridecyl) -4,4 '
-Tertiary phosphites such as isopropylidene diphenyl diphosphite, bis (tridecyl) pentaerythritol diphosphite, bis (nonylphenyl) pentaerythritol diphosphite, distearyl pentaerythritol diphosphite and polyphosphite; Lauryl Hydrogen Phosphate,
Secondary phosphites such as diphenyl hydrogen phosphite, dioleyl hydrogen phosphite, methyl acid phosphite, isodecyl acid phosphite, oleyl acid phosphite,
One or more kinds of acidic phosphoric acid esters such as octyl acid phosphite and cyclic phosphites such as 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide can be used.

Further, among the phosphorus-based antioxidants, the present inventors have found that a phosphorus-based antioxidant having at least one phosphite structure in a molecule in which a functional group adjacent to a phosphorus atom is an alkoxy group or a substituted alkoxy group. It has been found that the effect of preventing yellowing of the white paper portion is further enhanced when an antioxidant is used.

Although the reason for this is not clear, a phosphorus-based antioxidant having a phosphite structure in which the functional group adjacent to the phosphorus atom is a phenoxy group or a substituted phenoxy group is a phosphorus-based antioxidant, and the aromatic ring in the molecule is It is considered that the effect of yellowing of the white paper portion is lowered because it is easily excited and the phosphorus antioxidant itself turns yellow.

Examples of the phosphorus-based antioxidant having a high yellowing preventing effect on the white paper portion as described above include, for example, triethylphosphite, tris (2-ethylhexyl) phosphite, tridecylphosphite, tristearylphosphite, tris (tridecyl). ) Phosphite, dilauryl hydrogen phosphite, bis (tridecyl) pentaerythritol diphosphite, distearyl pentaerythritol diphosphite and the like can be mentioned.

The phosphorus antioxidant in the present invention is preferably 0.1 to 2 with respect to 100 parts by weight of the inorganic pigment.
0.0 solid part by weight, more preferably 0.1 to 1
0.0 solid part by weight. If the addition amount is less than 0.1 solid parts by weight, a sufficient yellowing preventing effect cannot be obtained, and if the addition amount exceeds 20.0 solid parts by weight, the yellowing preventing effect is not improved. It may adversely affect other characteristics (print density, ink absorbency, etc.).

Preferred as the inorganic pigment contained in the ink receiving layer of the ink jet recording sheet of the present invention is B.
An inorganic pigment having an ET specific surface area of 100 m ² / g or more, and more preferably 100 to 700. By using an inorganic pigment having such a specific surface area, high printing density and excellent ink absorbency can be achieved. If the BET specific surface area of the inorganic pigment is less than 100 m ² / g, sufficient printing density and ink absorbency cannot be obtained, which is not preferable.

As the inorganic pigment in the present invention, 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 non- Examples thereof include crystalline silica, colloidal silica, colloidal alumina, pseudo-boehmite, aluminum hydroxide, alumina, lithopone, zeolite, hydrohalloysite, magnesium carbonate, magnesium hydroxide and the like.

In the present invention, among the above-mentioned inorganic pigments, particularly when at least one kind of inorganic pigment selected from synthetic amorphous silica or cationic colloid particles is used, the print density and ink absorbency are further increased. Therefore, it is preferable.

The term "cationic colloidal particles" as used in the present invention means particles which are suspended and dispersed in water to form a colloidal shape, and the surface of the particles is positively charged.
Examples thereof include alumina sol such as boehmite and pseudo-boehmite, colloidal alumina, and particles obtained by coating the surface of colloidal silica particles with alumina as disclosed in JP-B-47-26959.

In the ink receiving layer of the present invention, a dye component of the water-based ink is added in order to impart water resistance to the ink jet recording sheet so as to prevent water from flowing out or bleeding due to water dripping or moisture absorption. Secondary amines and tertiary amines that form insoluble salts with sulfonic acid groups, carboxyl groups, amino groups, etc. in water-soluble direct dyes and water-soluble acid dyes,
It is possible to add a cationic dye fixing agent consisting of a quaternary ammonium salt. Usually, when a cationic dye fixing agent is added to the ink receiving layer, the yellowing of the white paper portion during storage in a file is aggravated, but in the present invention, the white paper portion is prevented by the yellowing prevention effect of the phosphorus-based antioxidant. The yellowing of the yellow is suppressed.

The ink receiving layer in the present invention may contain an adhesive together with the inorganic pigment and the phosphorus-based antioxidant in order to enhance the adhesive strength between the inorganic pigments and between the ink receiving layer and the support. Examples of the adhesive include polyvinyl alcohol, silanol-modified polyvinyl alcohol, vinyl acetate, oxidized starch, etherified starch, cellulose derivatives such as carboxymethyl cellulose and hydroxyethyl cellulose, casein, gelatin, soybean protein, silyl-modified polyvinyl alcohol, etc .; maleic anhydride. Conjugated diene copolymer latex such as acid resin, styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer; polymer or copolymer of acrylic acid ester and methacrylic acid ester, polymer of acrylic acid and methacrylic acid Or an acrylic polymer latex such as a copolymer; a vinyl polymer latex such as an ethylene vinyl acetate copolymer; or a functional group-modified monomer with a functional group-containing monomer such as a carboxyl group of these various polymers Body latex; Water-based adhesive such as thermosetting synthetic resin such as melamine resin, urea resin; Synthetic resin such as polymethylmethacrylate, polyurethane resin, unsaturated polyester resin, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, alkyd resin One or more adhesives can be used. In addition, the use of known natural or synthetic resin adhesives is not particularly limited.

The amount of the adhesive compounded is 100% of the inorganic pigment.
It is from 3 to 70 solid parts by weight, preferably from 5 to 50 solid parts by weight, based on the solid parts by weight. When it is less than 3 solid parts by weight, the coating strength of the ink receiving layer is insufficient and exceeds 70 solid parts by weight. In some cases, depending on the type of inkjet recording device, the ink absorbency may be reduced.

Further, as other additives, pigment dispersants, thickeners, fluidity improvers, defoamers, defoamers, mold release agents,
A foaming agent, a penetrating agent, a coloring dye, a coloring pigment, a fluorescent whitening agent, an ultraviolet absorber, an antiseptic agent, an anti-bacterial agent, a water resistance agent, a wet paper strength enhancer, a dry paper strength enhancer, etc. may be appropriately blended. it can.

In the present invention, the surface of the ink receiving layer may be provided with a coating layer (hereinafter abbreviated as a gloss developing layer) which gives the gloss of commercially available art coated paper.

In the method for producing an ink jet recording sheet according to the present invention, a BET specific surface area of 1 is mainly used on a support.
An ink receiving layer coating liquid consisting of an inorganic pigment and an adhesive of 00 m ² / g or more is applied to form an ink receiving layer, and then a phosphorus-based antioxidant solution or its emulsion is applied on the ink receiving layer. The phosphorus-containing antioxidant is impregnated and carried in the ink-receiving layer, and the phosphorus-containing antioxidant or its emulsion is mixed in the ink-receiving layer composition to receive the ink. A layer coating liquid is prepared, the ink receiving layer coating liquid is applied on a support to form an ink receiving layer, and a phosphorus-based antioxidant is carried in the ink receiving layer. .

The phosphorus-based antioxidant in the present invention is prone to hydrolysis due to its molecular structure. Therefore, the phosphorus-based antioxidant is dissolved / dispersed in a solvent having good compatibility such as alcohol or a solution obtained by emulsification according to a conventional method. Is preferably applied and carried on the ink receiving layer so as to be carried in the ink receiving layer.

When a phosphorus-based antioxidant which easily hydrolyzes is mixed with an aqueous ink-receiving layer coating liquid and used,
It is not preferable because the effect of preventing yellowing of the phosphorus-based antioxidant decreases.

Examples of phosphorus-based antioxidants which are resistant to hydrolysis include tridecyl phosphite, tris (tridecyl) phosphite, tris (2,4-di-t-butylphenyl) phosphite, tetra (tridecyl).
Phosphorus antioxidants such as -4,4'-isopropylidene diphenyl diphosphite and tris (mono, dinonylphenyl) phosphite should be emulsified and mixed in the ink receiving layer coating solution according to a conventional method. Is also possible, and like 9,10-dihydro-9-oxa-10phosphaphenanthrene-10-oxide, the hydrolysis reaction is a parallel reaction, and the phosphorus-based system returns to its original structure when it is again made anhydrous. Regarding the antioxidant, it is also possible to use it by mixing it directly into the coating liquid for the ink receiving layer without emulsifying.

The method for providing the ink receiving layer in the present invention may be either an on-machine coater or an off-machine coater. For example, conventionally known various devices such as an air knife coater, a curtain coater, a die coater, a blade coater, a gate roll coater, a bar coater, a rod coater, a roll coater, a bill blade coater, a short dwell blade coater, and a size press are on-machine or Can be used off-machine. Further, after coating, it is also possible to finish using a calendar device such as a machine calendar, a TG calendar, a super calendar, and a soft calendar.

Further, by providing the gloss-developing layer on the ink receiving layer by a cast coating method, it is possible to obtain a gloss feeling comparable to that of a commercially available cast coated paper.

The coating amount of the ink receiving layer in the present invention is not particularly limited, but is preferably 1 to 30 g / m ² . When the coating amount is less than 1 g / m ^2, it is not preferable because sufficient printing density and ink absorbency cannot be obtained, and when the coating amount exceeds 30 g / m ² , curling property of the recording sheet is deteriorated, which is not preferable. . Further, the ink receiving layer can be applied by coating a certain fixed amount of coating in several times.
The gloss is improved as compared with the case where the coating amount is applied at one time.

As a method of coating the phosphorus antioxidant solution or its emulsion on the ink receiving layer in the present invention, either an on-machine coater or an off-machine coater may be used. For example, a conventionally known air knife coater,
Curtain coater, die coater, blade coater,
Various devices such as a gate roll coater, a bar coater, a rod coater, a roll coater, a bill blade coater, a short dwell blade coater, and a size press can be used on machine or off machine. Also, a sprayer using compressed air may be used.
Further, after coating, it is also possible to finish using a calendar device such as a machine calendar, a TG calendar, a super calendar, and a soft calendar.

The support used in the present invention is LB
Chemical pulp such as KP, NBKP, GP, PGW, RM
P, TMP, CTMP, CMP, mechanical pulp such as CGP, wood pulp such as waste paper pulp such as DIP, and conventionally known pigments as a main component, and a binder and a sizing agent, a fixing agent, a yield improving agent, a cationizing agent, Starch, polyvinyl alcohol, and base paper manufactured by various devices such as fourdrinier paper machine, cylinder paper machine, twin wire paper machine, etc. A base paper provided with a size press or an anchor coat layer, and coated paper such as art paper, coated paper, cast coated paper provided with a coated layer thereon are also included. Such base paper and coated paper may be provided with the coating layer according to the present invention as they are,
For the purpose of controlling flattening, machine calendar,
You may use calendar devices, such as a TG calendar and a soft calendar. The basis weight of the support is usually 40 to 300 g / m ² , but is not particularly limited.

A back coat layer may be coated on the opposite surface of the ink receiving layer sandwiching the support in order to impart curl suitability.
Tabular pigments and hydrohaloysite are preferred.

The ink referred to in the present invention means the following colorants,
A recording liquid composed of a liquid medium and other additives. Examples of the colorant include water-soluble dyes such as direct dyes, acid dyes, basic dyes, reactive dyes and food dyes.

As the ink solvent, water and various water-soluble organic solvents such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol,
C1-C4 alkyl alcohols such as tert-butyl alcohol and isobutyl alcohol; amides such as dimethylformamide and dimethylacetamide; acetone,
Ketones or ketone alcohols such as diacetone alcohol; ethers such as tetrahydrofuran and dioxane; polyalkylene glycols such as polyethylene glycol and polypropylene glycol; ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,2,6- Alkylene glycols having 2 to 6 alkylene groups such as hexanetriol, thiodiglycol, hexylene glycol and diethylene glycol; multivalent such as glycerin, ethylene glycol methyl ether, diethylene glycol methyl (or ethyl) ether and triethylene glycol monomethyl ether Examples thereof include lower alkyl ethers of alcohol. 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 preferable. As other additives, for example,
Examples thereof include PH regulators, sequestering agents, antioxidants, antifungal agents, viscosity regulators, surface tension regulators, wetting agents, surfactants, and rust inhibitors.

The ink jet recording sheet according to the present invention is not limited to use as an ink jet recording sheet, and may be used as any recording sheet that uses a liquid ink during recording. For example, an ink sheet in which a heat-fusible ink containing a heat-fusible substance, a dye or pigment as a main component is applied on a thin support such as a resin film, high-density paper, or synthetic paper is heated from the back side of the ink sheet to remove the ink. An image-receiving sheet for thermal transfer recording that is melted and transferred, an inkjet recording sheet that heat-melts a heat-meltable ink to form fine droplets and performs flight recording, an inkjet recording sheet that uses an ink in which an oil-soluble dye is dissolved in a solvent, photopolymerization Examples thereof include an image receiving sheet corresponding to a light and pressure sensitive donor sheet using microcapsules containing a type monomer and colorless or colored dyes and pigments.

The common feature of the above recording sheets is that the ink is in a liquid state at the time of recording. Liquid ink cures,
By solidification or fixing, the ink penetrates or spreads in the depth direction or the horizontal direction of the ink receiving layer of the recording sheet.
The various recording sheets described above require absorptivity according to their respective systems, and the inkjet recording sheet of the present invention may be used as the various recording sheets described above.

Further, the ink jet recording sheet of the present invention may be used as a recording sheet for heating and fixing the toner of the electrophotographic recording system which is widely used in copying machines, printers and the like. Further, a pressure-sensitive adhesive layer is coated on the opposite surface of the ink-receiving layer sandwiching the support,
It can also be applied to label applications.

[0050]

The ink jet recording sheet of the present invention comprises an ink receiving layer on a support containing an inorganic pigment having a BET specific surface area of 100 m ² / g or more and an adhesive and carrying a phosphorus-based antioxidant. Is. The phosphorous antioxidant in the ink receiving layer suppresses the oxidation of the phenolic antioxidant to the quinone structure, which is considered to be the cause of the yellowing of the recording sheet when saving the file, thus significantly preventing the yellowing when saving the file. can do. Further, the inorganic pigment having a high specific surface area can improve printing density and ink absorbability. An ink jet recording medium having such a phosphorus-based antioxidant and an inorganic pigment contained in the ink-receiving layer when the ink-receiving layer has a high print density and excellent ink absorbency and has a significantly reduced yellowing of the white paper portion. A recording sheet is obtained.

[0051]

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

Antioxidant dispersions A to G having the following formulations were prepared in advance.

[Antioxidant Dispersion Liquid A] Triphenyl phosphite (JP-360: manufactured by Johoku Chemical Co., Ltd.) 10 parts Isopropyl alcohol 90 parts

[Antioxidant Dispersion Liquid B] Tridecyl phosphato (JP-310: manufactured by Johoku Chemical Co., Ltd.) 10 parts Isopropyl alcohol 90 parts

[Antioxidant Dispersion Liquid C] Dilauryl Hydrogen Phosphite (JP-213D: manufactured by Johoku Chemical Co., Ltd.) 10 parts Isopropyl alcohol 90 parts

[Antioxidant Dispersion Liquid D] Vise (tridecyl) pentaerythritol diphosphite (PEP-8: manufactured by Asahi Denka Co., Ltd.) 10 parts Isopropyl alcohol 90 parts

[Antioxidant Dispersion E] Butylhydroxytoluene (BHT: Wako Pure Chemical Industries, Ltd.) 10 parts Isopropyl alcohol 90 parts

[Antioxidant Dispersion Liquid F] Stearyl -β- (3,5-di-t-butyl-4-humanoxyphenyl) propionate (A050: Asahi Denka Kogyo Co., Ltd.) 10 parts Isopropyl alcohol 90 parts

[Antioxidant Dispersion Liquid G] Dilauryl 3,3′-thiodipropionate (Rasmit LG: Daiichi Kogyo Seiyaku Co., Ltd.) 10 parts Isopropyl alcohol 90 parts

Example 1 The support was composed of light calcium carbonate / heavy calcium carbonate / talc based on 100 parts of wood pulp consisting of 80 parts of LBKP (freeness of 400 mlcsf) and 20 parts of NBKP (freeness of 480 mlcsf). 20 parts of pigment having a ratio of 10/10/10, 0.10 parts of commercial alkyl ketene dimer,
After preparing 0.03 part of a commercially available cationic acrylamide, 1.0 part of a commercially available cationized starch and 0.5 part of a sulfuric acid band, papermaking was carried out with a Fourdrinier paper machine to obtain a support having a basis weight of 90 g / m ² .

The ink receiving layer was coated on the surface of the support.
The coating composition of the ink receiving layer has a BET specific surface area of 270 m ²
/ g of synthetic amorphous silica (FINESEAL X-37B: manufactured by Tokuyama Soda), 100 parts, polyvinyl alcohol (PVA1
17: Kuraray) 30 parts, cationic dye fixing agent (Sumireds resin 1001: Sumitomo Chemical Co., Ltd.) 20 parts were prepared, and the coating liquid was dried with an air knife coater to a dry coating amount of 8 g / m ² . Was coated on the support and dried. Then, the antioxidant dispersion liquid A was applied and impregnated on the ink receiving layer with a roll coater so that the solid content was 0.5 solid parts with respect to 100 solid parts by weight of the inorganic pigment, and dried to form an inkjet recording of Example 1. A sheet was prepared.

Example 2 A support was obtained in the same manner as in Example 1. The ink receiving layer was coated and dried in the same manner as in Example 1. Thereafter, the antioxidant dispersion liquid B was applied and impregnated on the ink receiving layer with a sprayer so as to be 0.5 solid parts by weight relative to 100 solid parts by weight of the inorganic pigment, to prepare an ink jet recording sheet of Example 3. did.

Example 3 A support was obtained in the same manner as in Example 1. The ink receiving layer was applied on the surface of the support. The coating composition for the ink receiving layer was 100 parts of synthetic amorphous silica (Fineseal X-37B: manufactured by Tokuyama Soda), polyvinyl alcohol (PVA117:
30 parts of Kuraray), 30 parts of colloidal silica (Snowtex-O: Nissan Kagaku), 20 parts of a cationic dye fixing agent (SUMIREZ RESIN 1001: Sumitomo Chemical Co., Ltd.) were prepared and these coating solutions were prepared with an air knife. By the coater
The support was coated and dried so that the dry coating amount was 8 g / m ² .

Then, a gloss developing layer was applied to the surface of the ink receiving layer. As the colloidal particles, the coating composition for the gloss-developing layer contains 100 organic pigments (L8999: manufactured by Asahi Kasei Co., Ltd.) containing polystyrene having a mean particle size of 200 nm as a main component.
Parts, 30 parts of an acrylic latex (SX984A1: made by Japan Synthetic Rubber) having an average particle size of 50 nm as a synthetic polymer latex, 1 part of commercially available potassium oleate as a release agent, and a solid content concentration of 30%, These were prepared. Then, this coating liquid was cast on the surface of the ink receiving layer by a direct method so that the dry coating amount was 3 g / m ² by a roll coater. Then, antioxidant dispersion C
Is coated on the ink-receiving layer with a roll coater so that the amount is 0.5 solid parts by weight per 100 parts by weight of the inorganic pigment.
The ink was impregnated and dried to prepare an inkjet recording sheet of Example 3.

Example 4 The ink jet ink of Example 4 was prepared in the same manner as in Example 1 except that the antioxidant dispersion liquid A of Example 1 was changed to the antioxidant dispersion liquid D as the coating composition for the ink receiving layer. A recording sheet was prepared.

Example 5 In the same manner as in Example 1 except that the antioxidant dispersion A of Example 1 was changed to an emulsion of tris (mono, dinonylphenyl) phosphite (329KE: manufactured by Asahi Denka Kogyo Co., Ltd.). An inkjet recording sheet of Example 5 was produced.

Example 6 As the coating composition for the ink receiving layer, the antioxidant dispersion liquid A of Example 1 was changed to the antioxidant dispersion liquid D, and this antioxidant dispersion liquid was changed to the phosphorus-based solution in the liquid. Antioxidant is inorganic pigment 10
An ink jet recording sheet of Example 6 was produced in the same manner as in Example 1 except that the ink receiving layer was impregnated so that the amount was 0.05 solid parts by weight relative to 0 solid parts by weight.

Example 7 The ink receiving layer was prepared by adding the antioxidant dispersion of Example 6 so that the phosphorus antioxidant in the solution was 22.0 solid parts by weight based on 100 parts by weight of the inorganic pigment. An inkjet recording sheet of Example 9 was produced in the same manner as in Example 6 except that the ink was impregnated therein.

Example 8 In the same manner as in Example 4 except that the synthetic amorphous silica of Example 4 was changed to ultrafine calcium carbonate having a BET specific surface area of 105 m ² / g as a coating composition for the ink receiving layer. Example 8
An inkjet recording sheet of was prepared.

Example 9 As a coating composition for the ink receiving layer, the synthetic amorphous silica of Example 4 was used as a cationic alumina hydrate having a BET specific surface area of 275 m ² / g (Cataloid AS-3: manufactured by Catalysis Kasei). An inkjet recording sheet of Example 9 was produced in the same manner as in Example 4 except that the above was changed to.

Example 10 As a coating composition for an ink receiving layer, the synthetic amorphous silica of Example 4 was applied to synthetic amorphous silica having a BET specific surface area of 120 m ² / g (Mizukasil NP-8: manufactured by Mizusawa Chemical Co., Ltd.). An ink jet recording sheet of Example 10 was produced in the same manner as in Example 4 except that it was changed.

Example 11 As a coating composition for an ink receiving layer, the synthetic amorphous silica of Example 4 was mixed with synthetic amorphous silica having a BET specific surface area of 380 m ² / g (Mizukasil P-78C, manufactured by Mizusawa Chemical Co., Ltd.). An ink jet recording sheet of Example 11 was produced in the same manner as in Example 4 except that it was changed.

Example 12 A support was obtained in the same manner as in Example 1. The ink receiving layer was applied on the surface of the support. The coating composition for the ink receiving layer was 100 parts of synthetic amorphous silica (Fineseal X-37B: manufactured by Tokuyama Soda), polyvinyl alcohol (PVA117:
These were prepared as 30 parts by Kuraray Co., Ltd., and these coating solutions were applied and dried on a support with an air knife coater so that the dry coating amount was 8 g / m ² . Then, the antioxidant dispersion D was applied and impregnated on the ink-receiving layer with a roll coater so as to be 0.5 solid parts by weight with respect to 100 solid parts by weight of the inorganic pigment, and dried to form an inkjet recording of Example 12. A sheet was prepared.

Example 13 A support was obtained in the same manner as in Example 1. The ink receiving layer was applied on the surface of the support. The coating composition for the ink receiving layer was 100 parts of synthetic amorphous silica (Fineseal X-37B: manufactured by Tokuyama Soda), polyvinyl alcohol (PVA117:
Kuraray) 30 parts, cationic dye fixing agent (Sumireds resin 1001: Sumitomo Chemical Co., Ltd.) 20 parts, and an emulsion of tris (mono, dinonylphenyl) phosphite (32
9KE: manufactured by Asahi Denka Co., Ltd.)
This coating liquid is dried with an air knife coater to a dry coating amount of 8
Example 13 was applied to a support and dried to obtain g / m ^2.
An inkjet recording sheet of was prepared.

Example 14 The emulsion of tris (mono, dinonylphenyl) phosphite of Example 12 was treated with 9,10-dihydro-9-oxa-.
An inkjet recording sheet of Example 14 was produced in the same manner as in Example 12 except that 10-phosphaphenanthrene-10-oxide (HCA: manufactured by Sanko Kagaku) was used.

Comparative Example 1 A support was obtained in the same manner as in Example 1. The ink receiving layer was applied on the surface of the support. The coating composition of the ink receiving layer is B
Commercially available light calcium carbonate with an ET specific surface area of 5 m ² / g 100
Part, polyvinyl alcohol (PVA117: made by Kuraray)
30 parts, cationic dye fixing agent (Sumired's resin 10
(01: manufactured by Sumitomo Chemical Co., Ltd.), and these were prepared at a solid content concentration of 15%. This coating liquid was applied onto a support by an air knife coater so that the dry coating amount was 8 g / m ^2, and dried to prepare an inkjet recording sheet of Comparative Example 1.

Comparative Example 2 Comparative Example 2 except that the calcium carbonate of Comparative Example 1 was changed to synthetic amorphous silica having a BET specific surface area of 40 m ² / g (Mizukasil P527 manufactured by Mizusawa Chemical Co., Ltd.) as a coating composition for the ink receiving layer. An inkjet recording sheet of Comparative Example 2 was prepared in the same manner as in Example 1.

Comparative Example 3 As a coating composition for the ink receiving layer, the calcium carbonate of Comparative Example 1 was changed to synthetic amorphous silica having a BET specific surface area of 270 m ² / g (Fineseal X37B: manufactured by Tokuyama Soda). An inkjet recording sheet of Comparative Example 3 was prepared in the same manner as in Comparative Example 1.

Comparative Example 4 A support was obtained in the same manner as in Example 1. The ink receiving layer was applied on the surface of the support. The coating composition of the ink receiving layer is B
Synthetic amorphous silica with ET specific surface area of 270 m ² / g (Fineseal X37B: Tokuyama Soda) 100 parts, polyvinyl alcohol (PVA117: Kuraray) 30 parts, cationic dye fixing agent (SUMIREZ RESIN 1001: Sumitomo Chemical Co., Ltd.) ) Was used to prepare a solid content concentration of 15%, and these solutions were prepared, and the coating solution was applied to a support by an air knife coater so that the dry coating amount was 8 g / m ² and dried. After that, the antioxidant dispersion E is applied onto the ink receiving layer by the inorganic pigment 1
An ink jet recording sheet of Comparative Example 4 was produced by coating and impregnating with a roll coater so as to be 0.5 solid parts by weight relative to 00 solid parts by weight and drying.

Comparative Example 5 Ink Jet of Comparative Example 5 was carried out in the same manner as Comparative Example 4 except that the antioxidant dispersion E of Comparative Example 4 was changed to the antioxidant dispersion F as the coating composition for the ink receiving layer. A recording sheet was prepared.

Comparative Example 6 A support was obtained in the same manner as in Example 1. The ink receiving layer was applied on the surface of the support. The coating composition for the ink receiving layer was 100 parts of synthetic amorphous silica (Fineseal X-37B: manufactured by Tokuyama Soda), polyvinyl alcohol (PVA117:
(Kuraray Co., Ltd.) 30 parts thereof were prepared, and this coating solution was applied to a support by an air knife coater so as to have a dry coating amount of 8 g / m ² and dried to prepare an inkjet recording sheet of Comparative Example 6. did.

Comparative Example 7 9.10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide of Example 2 was converted to bis (tridecyl) pentaerythritol diphosphite (P
An ink jet recording sheet of Comparative Example 7 was produced in the same manner as in Example 2 except that EP-8: manufactured by Asahi Denka Kogyo Co., Ltd. was used.

Comparative Example 8 An ink jet recording sheet of Comparative Example 8 was prepared in the same manner as in Example 1 except that the antioxidant dispersion liquid A of Example 1 was changed to the antioxidant dispersion liquid G.

Comparative Example 9 A support was obtained in the same manner as in Example 1. The ink receiving layer is
It was applied on the surface of the support. The coating composition of the ink receiving layer,
BET specific surface area 12 surface-treated with aluminum compound
100 parts of 5 m ² / g of synthetic amorphous silica and 30 parts of polyvinyl alcohol (PVA 117: made by Kuraray) were prepared, and the coating liquid was dried by an air knife coater to a dry coating amount of 8 g / m ^2. An ink jet recording sheet of Comparative Example 9 was prepared by applying the coating on the support and drying.

Comparative Example 10 A support was obtained in the same manner as in Example 1. The ink receiving layer is
It was applied on the surface of the support. The coating composition of the ink receiving layer,
50 parts of synthetic amorphous silica (FINESEAL X-37B: manufactured by Tokuyama Soda), rice starch powder (average particle size 4.9 μm) 50
Part, polyvinyl alcohol (PVA117: made by Kuraray)
An ink jet recording sheet of Comparative Example 10 was prepared by preparing 30 parts of the solution, and coating and drying the coating solution with an air knife coater so that the dry coating amount was 8 g / m ² .

Evaluations of Examples 1 to 14 and Comparative Examples 1 to 10 were carried out by the methods shown below, and the results are shown in Tables 1 and 2. The measurement and evaluation were performed under the environment specified in JIS P8111.

1) Printing Density Using an inkjet recording device (BJC-820J: made by Canon), a solid pattern was printed with black ink, and the optical reflection density of the printed portion was measured by Macbeth RD-918.

2) Ink absorbency Using the above ink jet recording apparatus, a heavy color rectangular pattern is printed with cyan ink and magenta ink, and the boundary between this pattern and the blank sheet is visually observed according to the following criteria. An evaluation was made. A: No distortion is observed at the boundary. B: A slight distortion is seen at the boundary. C: Distortion is seen in all of the boundaries. A or B evaluation is required for good ink absorbency.

3) Yellowing of white paper part [BHT method] BHT dimer (4,4'-methylenebis-
2,6-di-tert-butylphenol) isopyl alcohol 1% solution was spotted on the ink recording sheet so that the solid content was 0.5 g / m ^2, and the temperature was 20 ° C.
Under the condition of 65% RH, L ^* a ^* b ^* (C
A colorimetric color difference meter (CR100:
It was measured by Minolta). Then, the degree of yellowing of the white paper portion was evaluated by the difference in b ^* before and after the treatment (Δb ^* ). It should be noted that the smaller this value is, the smaller the yellowing change is.

[File method] A polypropylene plastic file bag (A4 size) containing 1.0% by weight of commercially available BHT was cut into a square of 5 cm x 5 cm in the vicinity of the center of one side, and the coated layer surface had holes. Put it in a file bag so that it hits the file side, leave it for a month in the room, take out the sample, and color the inkjet recording sheet before and after processing L ^* a ^* b ^* (coloring method according to CIE) It was measured with a color difference meter (CR100: manufactured by Minolta). The degree of yellowing of the white paper part depends on the difference in b ^* before and after processing (△
b ^* ), and a smaller value indicates less yellowing.

[0091]

[Table 1]

[0092]

[Table 2]

As is clear from Tables 1 and 2, in Examples 1 to 12, the ink receiving layer composition was mainly B.
An ink jet recording sheet comprising an inorganic pigment having an ET specific surface area of 100 m ² / g or more and an adhesive and having a phosphorus antioxidant in the ink receiving layer, the ink comprising the inorganic pigment and the adhesive on a support. An ink receiving layer is formed by applying a coating liquid for the receiving layer, and then a phosphorus-based antioxidant solution or its emulsion is applied on the ink receiving layer, and the phosphorus-containing antioxidant is impregnated in the ink receiving layer. An ink which is carried or prepared by mixing a phosphorus-based antioxidant or an emulsion thereof in an ink receiving layer composition composed of an inorganic pigment and an adhesive to prepare a coating liquid for the ink receiving layer, and coating the ink on a support. Since the ink jet recording sheet was manufactured by providing a receiving layer, and impregnating and carrying a phosphorus-based antioxidant in the ink receiving layer, the ink jet recording sheet has high printing density, excellent ink absorbency, and little yellowing of white paper. Bet the recording sheet was obtained.

Among them, the ink jet recording sheets of Examples 2 to 4 had at least one phosphite structure in which a functional group adjacent to a phosphorus atom was an alkoxy group or a substituted alkoxy group as a phosphorus-based antioxidant in the molecule. Since the phosphorus-based antioxidants described above were used, an inkjet recording sheet with less yellowing of the white paper portion than in Examples 1 and 5 was obtained.

Further, as is clear from Examples 4, 6 and 7, if the addition amount of the phosphorus-based antioxidant is 0.1 solid parts by weight or more based on 100 parts by weight of the inorganic pigment, a white paper part is obtained. The effect of preventing yellowing was further increased, and the effect of preventing yellowing of the white paper portion did not change even when the amount exceeded 20 parts by weight. Further, as is apparent from Examples 4 and 8-11, when cationic colloidal particles such as synthetic amorphous silica or cationic alumina hydrate among inorganic pigments are used,
In addition, when the BET specific surface area was large, an ink jet recording sheet having high print density and high ink absorbency was obtained.

Further, as is clear from Examples 4 and 12 and Comparative Examples 3 and 6, the ink jet recording sheet containing no phosphorus-based antioxidant has a white paper when a cationic dye fixing agent is added in order to obtain water resistance. The yellow discoloration of the white portion was considerably deteriorated, but in the ink jet recording sheet containing the phosphorus-based antioxidant, the yellow discoloration of the white paper portion was small despite the addition of the cationic dye fixing agent.

On the other hand, in the ink jet recording sheets of Comparative Examples 1 and 2, the BET of the inorganic pigment contained in the ink receiving layer was used.
Since the specific surface area was less than 100 m ² / g, the print density and ink absorbency were low. The ink jet recording sheet of Comparative Example 3 had a high BET specific surface area of 100 m ² / g or more because it used synthetic amorphous silica, so the printing density and ink absorbency were high, but it did not contain a phosphorus-based antioxidant, and therefore the white paper portion The yellow color change was extremely bad. In the inkjet recording sheets of Comparative Examples 4 and 5, since the phenolic antioxidant was used as the antioxidant, the yellow discoloration of the white paper portion was further deteriorated.

In the ink jet recording sheet of Comparative Example 7, an ink receiving layer composition comprising an inorganic pigment and an adhesive was mixed with a phosphorus-based antioxidant which is susceptible to hydrolysis to prepare an ink receiving layer coating liquid. Since the adjustment was made, the yellowing of the white paper portion was worse than in Example 4.

Further, the ink jet recording sheets of Comparative Examples 8 to 10 contained the thioether antioxidant, the synthetic silica surface-treated with the aluminum compound, and the starch particles, thereby suppressing the yellowing of the white paper portion. However, the effect of preventing yellowing of the white paper portion was lower than that of the inkjet recording sheet containing the phosphorus-based antioxidant of the example.

[0100]

The ink jet recording sheet of the present invention is
An ink-receiving layer composition comprising an inorganic pigment having a specific BET specific surface area and an adhesive, wherein a phosphorus-based antioxidant is carried in the ink-receiving layer to maintain high printing density and excellent ink absorbability. However, the yellowing of the white paper portion can be significantly reduced.

Claims (11)

[Claims] 1. An ink jet recording sheet having an ink receiving layer provided on a support, wherein the ink receiving layer composition is mainly composed of an inorganic pigment and an adhesive having a BET specific surface area of 100 m ² / g or more, and the ink receiving layer. An inkjet recording sheet, comprising a phosphorus-based antioxidant supported in a layer. 2. The phosphorus-based antioxidant has at least one phosphorous acid structure having a functional group, which is an alkoxy group or a substituted alkoxy group, adjacent to a phosphorus atom. Inkjet recording sheet. 3. The phosphorus-based antioxidant is 0.1 to 20.0 solid parts by weight based on 100 solid parts by weight of the inorganic pigment in the ink receiving layer. Inkjet recording sheet. 4. The inkjet recording sheet according to claim 1, wherein the inorganic pigment is at least one selected from synthetic amorphous silica and cationic colloidal particles. 5. The ink-receiving layer composition contains a cationic dye fixing agent, which is characterized in that
The inkjet recording sheet according to any one of 1. 6. A method for producing an ink jet recording sheet having an ink receiving layer provided on a support, wherein the ink receiving layer mainly comprises an inorganic pigment having a BET specific surface area of 100 m ² / g or more and an adhesive. A coating liquid is applied to form the ink receiving layer, and a phosphorus-based antioxidant solution or its emulsion is applied onto the ink receiving layer, and the ink receiving layer is impregnated and supported. And a method for manufacturing an inkjet recording sheet. 7. The phosphorus-based antioxidant has at least one phosphorous acid structure in which a functional group, which is an alkoxy group or a substituted alkoxy group, is adjacent to a phosphorus atom, and at least one phosphorous acid structure is contained. Method for manufacturing inkjet recording sheet. 8. The phosphorus-based antioxidant is 0.1 to 20.0 solid parts by weight relative to 100 solid parts by weight of the inorganic pigment in the ink receiving layer. Method for manufacturing inkjet recording sheet. 9. A method for producing an ink jet recording sheet having an ink receiving layer provided on a support, which comprises mainly BE.
A phosphorus-based antioxidant or its emulsion is mixed in an ink-receiving layer composition composed of an inorganic pigment and an adhesive having a T specific surface area of 100 m ² / g or more to prepare an ink-receiving layer coating liquid, and the ink-receiving layer coating liquid is prepared. A method for producing an inkjet recording sheet, comprising applying a liquid on the support to form the ink receiving layer, and supporting the phosphorus-based antioxidant in the ink receiving layer. 10. The phosphorus-based antioxidant has at least one phosphorous acid structure having a functional group, which is an alkoxy group or a substituted alkoxy group, adjacent to a phosphorus atom, according to claim 9. Method for manufacturing inkjet recording sheet. 11. The phosphorus-based antioxidant is 0.1 to 20.0 with respect to 100 parts by weight of the inorganic pigment in the ink receiving layer.
It is solid weight part, The claim 9 or 10 characterized by the above-mentioned.
A method for producing the inkjet recording sheet described above.