JP2003291504A - Inkjet recording sheet for proofreading - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording sheet for proofreading, which is excellent in hue, gloss value and appearance in inkjet printing, and has a feel remarkably similar to that of printing paper serving as a proofreading object. <P>SOLUTION: In this inkjet recording sheet for the proofreading, at least one gloss adjusting layer and at least ink absorbing layer are sequentially applied onto a substrate which is composed of pulp fibers. The inkjet recording sheet is characterized as follows: the gloss adjusting layer contains a white pigment equivalent to 40 mass% or more of total solids; and a haze index, which is prescribed as follows, of the ink absorbing layer is 20% or less. The haze index is prescribed as follows: the haze value of a transparent polyethylene film with a haze value of 2% or less, which is specified by JIS-K7105, is set at A (%); the haze value of a material, in which the ink absorbing layer is applied for drying onto on the transparent polyethylene film so that a solid content can be set at 10 g/m<SP>2</SP>, is set at B (%); and in this case, a value obtained by B-A (%) serves as the haze index of the ink absorbing layer. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording sheet used for print proofreading, which utilizes an ink jet recording system. More specifically, the present invention relates to an inkjet recording sheet having a texture similar to that of the target printing paper and suitable for print proofing.

[0002]

2. Description of the Related Art In recent years, with the remarkable progress of ink jet printers and plotters, it has become possible to easily obtain full-color and high-definition images.

The ink jet recording system is a system in which minute droplets of ink are ejected and adhered to a recording sheet such as paper by various operating principles to record images, characters and the like. 2. Description of the Related Art Inkjet printers and plotters have rapidly become widespread in recent years in various applications as hard copy creation devices for image information such as characters and various figures created by computers. In particular, a color image formed by a multi-color ink jet method can obtain a recording comparable to that of a multi-color printing by a plate making method or a printing by a color photographic method, and further, in an application with a small number of copies. Is being widely applied because it is cheaper than printing or photographic technology.

In recent years, a recording sheet using an ink jet recording method has been often used as a print proof for confirming the finish of a printed matter in advance. In recent printers, products dedicated to printing and proofreading have appeared on the market, and commercialization of recording sheets corresponding to them has been desired. In the inkjet recording sheet used for print proofing, it is most important to faithfully reproduce the color and texture of the printing paper.

The color tone of the printing paper generally used for printing is not pure white, but is generally given a color tone according to the purpose. On the other hand, inkjet paper is required to have ink absorbability and color reproducibility, and the pigments, adhesives, and various additives to be used have been devised. As the pigment, a porous synthetic pigment is often used in order to obtain absorbency, and in addition, in order to make the color quality of the inkjet image clear, the hue is a unique whiteness derived from the pigment.

In particular, matte ink jet paper with low gloss often uses synthetic amorphous silica with low gloss and smoothness, and inkjet glossy paper with high gloss has low synthetic gloss and smoothness. On the ink absorption layer using crystalline silica, colloidal particles such as colloidal silica or alumina having a small particle size are coated as a gloss development layer, and then the wet surface is pressed against a heated mirror surface cast drum etc. Inkjet paper by a casting method, or by coating colloidal particles such as colloidal silica or alumina having a small particle size as a gloss-developing layer, drying, and then expressing gloss with a high-pressure calender such as a super calender. ing.

However, in order to obtain a high gloss by using such a method, the gloss developing layer is formed with a pressure higher than necessary in order to compensate for the low smoothness of the lower ink absorbing layer. Crushing reduces the fine pores and the surface area required for the ink jet recording paper, which lowers the ink absorbency and color developability.

Further, such an ink jet recording paper uses a coloring material such as a fluorescent dye, a coloring dye, or a coloring pigment,
It is common to adjust the hue of the ink absorbing layer or the gloss developing layer, and especially for proofing ink jet recording paper, the hue, gloss level, and the like as described in JP-A-12-343815.
In addition, the proofreading paper is made to have a feeling that it is not uncomfortable by making the basis weight approximate to the proofreading paper.

However, even if the hue, gloss value, and basis weight as described above are approximated to the paper to be calibrated, the texture, luster and appearance of the paper may differ due to the difference in pigment, base paper, or finishing method from the paper to be calibrated. Because there is a difference in feeling,
It was insufficient as a proofreading sheet.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to be suitable for print proofing, and to improve the ink absorbency in which not only the color difference from the proofreading paper, the gloss value, the basis weight, etc., but also the appearance texture, gloss feeling, etc. are improved. An object is to provide an excellent inkjet recording sheet.

[0011]

Therefore, as a result of intensive studies, the present inventors have made a proofreading in which one or more gloss adjusting layers and one or more ink absorbing layers are sequentially coated on a support made of pulp fibers. In the inkjet recording sheet, the gloss adjusting layer contains a white pigment in an amount of 40% by mass or more based on the total solid content, and the haze index of the ink absorbing layer is 20%.
By the following, it was found that it is possible to obtain the required characteristics as an inkjet recording sheet for proofing such as hue, appearance and gloss.

Further, it has been found that a more preferable effect can be obtained when the color index of the ink absorbing layer is 3 or less.

Further, from the surface of the ink absorbing layer, JIS-
JI measured by the measuring method specified by Z8722
The lightness index (L *) and perceptual chromaticity index (a *, b *) specified by S-Z8729, and the value of 75-degree specular gloss (Gs) specified by JIS-P8142 and printing of the calibration target The lightness index (L *) and perceived chromaticity index (a
*, B *) value and 7 specified by JIS-P8142
JIS-Z873 obtained from 5 degree specular gloss (Gs)
It has been found that a color difference (ΔE *) defined by 0 is 3 or less, and an absolute value of the 75 ° specular gloss difference (| ΔGs |) is 15 or less can achieve a more preferable effect. .

Further, the ink absorbing layer has an average primary particle diameter of 50 nm or less and an average secondary particle diameter of 300 nm.
It has been found that a further preferable effect can be obtained by containing the following inorganic fine particles and a hydrophilic binder and setting the solid content ratio of the hydrophilic binder to the inorganic fine particles to 5 to 40% by mass.

Further, when the smoothness of the gloss adjusting layer is 200 mmHg or less and the liquid transfer amount measured by the Bristow method at a contact time of 0.5 seconds is 10 g / m ² or less, a more preferable effect can be obtained. I found something.

Further, the coating thickness of the ink absorbing layer is 40.
μm or less, JIS-P8 from the surface of the ink absorption layer
It was found that a more preferable effect can be obtained by setting the degree of Cobb size defined by 140 to be 10 g / m ² or more.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The ink jet recording sheet of the present invention will be described in detail below.

The haze index referred to in the present invention is JI.
A haze value (%) of a transparent polyethylene film having a haze value of 2% or less measured by the measurement method defined by SK-7105 is A, and a haze value 2 measured by the measurement method defined by JIS K-7105. % When the haze value (%) after drying is applied by coating an ink absorbing layer having a solid content of 10 g / m ² on the transparent polyethylene film of not more than 10%.
It is a value obtained from -A (%).

More specific sample preparation conditions and measurement conditions are as follows: the coating liquid used for the ink image receiving layer is measured by a B-type viscometer at about 100 cps (room temperature of about 25 ° C., No. 2 spindle used, rotation speed of 60 rpm, 1 minute after measurement), then Poic integrating sphere haze meter SEP-H
A transparent polyethylene film having a haze value of 2% or less measured by S-D1 (manufactured by Nippon Seimitsu Engineering Co., Ltd.), product name:
Melinex 706-100μ (manufactured by Teijin DuPont Films Co., Ltd.) was coated with a wire bar so that a solid coating amount was 10 g / m ^2, and then the wind speed was 10 m / sec or less, and 30 A sample was prepared by drying with a dryer whose temperature was adjusted to ° C. The prepared sample was measured for haze value with the Poick integrating sphere type haze meter, and the haze value of the transparent polyethylene film before application was subtracted from the measured haze value of the film after application to obtain a haze index.

Further, the method for determining the haze index of two or more ink absorbing layers is as follows: the coating amount ratio of each ink absorbing layer is calculated from the total coating amount of the ink absorbing layers. The haze index was multiplied, and the value obtained by integrating the results was used as the haze index in the case of two or more ink absorbing layers.

When the haze index is more than 20%, the opacity of the ink absorbing layer is increased, the influence of the ink absorbing layer itself on the texture is increased, and the texture of the gloss adjusting layer is impaired, which is not preferable. More preferably,
The haze index is preferably 10% or less.

The color index referred to in the present invention is measured according to the measuring method specified in JIS-P8148, and the white PET film having a measured whiteness of 98 to 110% is measured according to the measuring method specified in JIS-Z8722. Lightness Index (L
*) And perceived chromaticity index (a *, b *) values, and JIS-P
Solid content 1 on a white PET film having a whiteness of 98 to 110% measured according to the measurement method specified in 8148.
JIS-Z8 after coating with 0 g / m ² ink absorption layer and drying
JIS measured according to the measurement method specified in 722
It is a value obtained from the color difference (ΔE *) defined by JIS-Z8730 of the values of the lightness index (L *) and the perceived chromaticity index (a *, b *) defined by -Z8729.

More specific sample preparation conditions and measurement conditions are as follows: the coating liquid used for the ink absorption layer is measured by a B-type viscometer at about 100 cps (room temperature about 25 ° C., No. 2 spindle used, rotation speed 60 rpm, (1 minute after measurement), a white PET film having a whiteness of 98 to 110% measured by a spectral color / whiteness meter PF-10 (manufactured by Nippon Denshoku Industries Co., Ltd.), product name: Melinex 6421 (Manufactured by Teijin DuPont Films Co., Ltd.) was coated with a wire bar capable of obtaining an appropriate coating amount so that the solid coating amount was 10 g / m ^2, and then the wind speed was about 10 m / sec or less and 3
A sample was prepared by drying with a dryer whose temperature was adjusted to 0 ° C. The prepared sample and the white PET film before coating were used for spectroscopic color difference meter Spectrolino (Gretag.
The values of lightness index (L *) and perceptual chromaticity index (a *, b *) were measured by Macbeth Co., and the measured lightness index (L *) and perceptual chromaticity index (a) of the film after coating were measured. *, B
The color difference (ΔE *) was obtained from the *) value and the lightness index (L *) and perceived chromaticity index (a *, b *) values of the transparent polyethylene film before coating and used as the color index.

Further, the color index of two or more ink absorbing layers can be obtained by adding the coating amount ratio of each ink absorbing layer to the coating amount ratio of each ink absorbing layer obtained from the total coating amount of the ink absorbing layer. The color index was multiplied, and the value obtained by integrating the values was used as the color index in the case of two or more ink absorbing layers.

When the color index is larger than 3, the hue and texture of the white pigment used in the printing paper for general commercial printing of the gloss developing layer is hindered by the ink absorbing layer which is colored or haze more than necessary. It was found to be unfavorable because it would end up. That is, the color index is preferably 3 or less.

As the white pigment of the gloss adjusting layer, it is preferable to use the same white pigment as that used for printing paper for general offset or gravure printing or other commercial printing. By applying a white pigment used for printing paper for general commercial printing, it was possible to obtain the same texture, glossiness and the like as the printing paper for commercial printing. or,
When the content of the white pigment in the gloss adjusting layer is at least 40% by mass or more, a texture similar to that of printing paper can be obtained.
The preferable content is 70% by mass or more.

The white pigment of the gloss adjusting layer in the present invention is, for example, light calcium carbonate, heavy calcium carbonate, magnesium carbonate, kaolin, talc, calcium sulfate,
White inorganic pigments such as barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, satin white, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate, aluminum hydroxide, lithopone, zeolite, hydrohalloysite, magnesium hydroxide, Examples include organic pigments such as styrene plastic pigments, acrylic plastic pigments, polyethylene fine particles, microcapsules, urea resin fine particles, and melamine resin fine particles, and one or more of these pigments can be appropriately used.

As the binder used in the gloss adjusting layer, starch derivatives such as oxidized starch, etherified starch and phosphoric esterified starch; carboxymethyl cellulose,
Cellulose derivatives such as hydroxyethyl cellulose;
Casein, gelatin, soybean protein, polyvinyl alcohol or derivatives thereof; polyvinylpyrrolidone, maleic anhydride resin, conjugated diene copolymer latex such as styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer; acrylic acid ester and methacrylic acid Acrylic polymer latex such as acrylic polymer such as acid ester polymer or copolymer; vinyl polymer latex such as ethylene vinyl acetate copolymer; or functional group such as carboxy group of these various polymers Functional group-modified polymer latex with contained monomer; Water-based adhesive such as thermosetting synthetic resin such as melamine resin and urea resin; Polymeric or copolymer resin of acrylic acid ester and methacrylic acid ester such as polymethylmethacrylate; Polyurethane resin, unsaturated Ester resins, vinyl chloride - can be exemplified vinyl acetate copolymer, polyvinyl butyral, a synthetic resin adhesive such as alkyd resin.

In the gloss adjusting layer of the present invention, other additives such as a pigment dispersant, a thickener, a dye fixing agent, a fluidity improving agent, an antifoaming agent, a defoaming agent, a releasing agent and a foaming agent are used. Agents, penetrants, coloring dyes, coloring pigments, optical brighteners, ultraviolet absorbers, antioxidants, antiseptics, antifungal agents, water resistance agents, wet paper strength enhancers,
A dry paper strength enhancer and the like may be appropriately blended, and these may be applied to both sides of the support.

Further, it is preferable that the gloss adjusting layer of the present invention is adjusted to a hue similar to that of the printing paper to be proofed by using a hue adjusting agent such as a coloring dye, a coloring pigment and a fluorescent brightening agent.

Furthermore, the proofreading ink jet recording sheet of the present invention is adjusted to have a color difference of 3 or less and a 75-degree specular gloss difference of 15% or less with respect to the printing paper to be calibrated so that it looks as the printing paper to be calibrated. It is preferable because the texture and glossiness are closer to each other.

More preferably, the absorbent support and the gloss adjusting layer have the same support and the same coating layer constitution as the printing paper to be calibrated in order to obtain the same hue, glossiness, texture and the like. For this reason, it is most preferable to apply the ink absorbing layer on the printing paper to be constituted.

In the constitution of the ink absorbing layer of the present invention, when the average primary particle diameter of the inorganic fine particles is larger than 50 nm,
The increase in the haze index of the ink absorption layer increases the opacity of the ink absorption layer, which affects the texture, gloss and texture of the gloss adjusting layer close to that of the printing paper to be calibrated. Therefore, the average primary particle diameter of the inorganic fine particles in the ink absorbing layer is preferably 50 nm or less.

Further, in the constitution of the ink absorbing layer of the present invention, when the average secondary particle diameter of the inorganic fine particles is larger than 300 nm, the haze index of the ink absorbing layer is increased similarly to the case where the primary particle diameter is large, and thus the ink absorbing layer is increased. Increases the opacity of the gloss adjustment layer, which affects the texture, gloss and texture of the printing paper that is close to the calibration target of the gloss adjustment layer. For that reason,
The average secondary particle diameter of the inorganic fine particles in the ink absorbing layer is 300 n
It is preferably m or less.

As the inorganic fine particles used in the ink absorbing layer of the present invention, one or more known white pigments can be used. For example, light calcium carbonate, heavy calcium carbonate, kaolin clay, delaminated clay, calcined clay, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, satin white, aluminum silicate, diatomaceous earth. , White inorganic such as calcium silicate, magnesium silicate, synthetic amorphous silica, fumed silica, colloidal silica, colloidal alumina, pseudo-boehmite, aluminum hydroxide, alumina, lithopone, zeolite, hydrohaloysite, magnesium carbonate, magnesium hydroxide Pigment, styrene plastic pigment, acrylic plastic pigment,
Examples include organic pigments such as polyethylene, microcapsules, urea resins, and melamine resins. Among the above, the primary particle diameter of vapor-phase method silica, colloidal silica, colloidal alumina, pseudo-boehmite alumina, etc. is especially 50 nm.
The following porous inorganic fine particles are preferable.

As the binder used in the ink absorbing layer, starch derivatives such as oxidized starch, etherified starch and phosphoric esterified starch; cellulose derivatives such as carboxymethyl cellulose and hydroxyethyl cellulose; casein, gelatin, soybean protein, polyvinyl Alcohol or its derivative; Polyvinylpyrrolidone, maleic anhydride resin, styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer and other conjugated diene copolymer latex; Polymer or copolymer of acrylic acid ester and methacrylic acid ester Acrylic polymer latex such as acrylic polymer such as polymer; vinyl polymer latex such as ethylene-vinyl acetate copolymer; or functional group modification of these various polymers with functional group-containing monomer such as carboxy group Polymer latex; melamine resins, water-based adhesives such as thermosetting synthetic resins such as urea resins;
Acrylic esters such as polymethylmethacrylate;
Methacrylic acid ester polymer or copolymer resin; polyurethane resin, unsaturated polyester resin, vinyl chloride-
Examples thereof include vinyl acetate copolymer, polyvinyl butyral, alkyd resin, and other synthetic resin adhesives.

Further, the compounding amount of the binder in the ink absorbing layer of the present invention is 3 to 40 parts by mass, preferably 5 to 30 parts by mass based on 100 parts by mass of the total amount of the porous pigment and, if necessary, other pigments. If it is less than 3 parts by mass, the coating strength of the ink receiving layer will be insufficient, and if it exceeds 40 parts by mass, the ink absorbency will decrease, which is not preferable.

In the ink absorbing layer of the present invention, other additives such as a pigment dispersant, a thickener, a dye fixing agent, a fluidity improving agent, a defoaming agent, a defoaming agent, a releasing agent and a foaming agent are used. , Penetrants, ultraviolet absorbers, antioxidants, preservatives, antifungal agents, water resistant agents, wet paper strength enhancers, dry paper strength enhancers, etc. It may be applied.

In the ink absorbing layer of the present invention, a coloring dye,
Coloring pigments, fluorescent whitening agents, and other hue adjusters may also be used as appropriate 1.
Although it is possible to mix more than one kind, it is not preferable to add more than necessary because the color index is deteriorated. As an index for adding the hue adjusting agent, the amount of addition so that the color index of the ink absorbing layer is 3 or less is preferable.

Further, the liquid transfer amount of the gloss adjusting layer of the present invention measured by the Bristow method at a contact time of 0.5 seconds is 10 g.
If it is larger than / m ² , the coating solution for the ink-absorbing layer during the application of the ink-absorbing layer remarkably absorbs the water-soluble component in the coating composition for the ink-absorbing layer, especially the water-soluble binder, into the gloss adjusting layer coating layer and the absorbent support. As a result, the coating layer strength of the ink absorption layer coating layer is significantly reduced, and the solid concentration of the ink absorption layer coating liquid increases, causing aggregation of the inorganic fine particles in the ink absorption layer, resulting in ink absorption. It was found that the haze of the layer coating layer was increased, and the same texture as that of the printing paper to be proofed obtained by the gloss adjusting layer could not be obtained.

Further, when the smoothness of the gloss adjusting layer of the present invention is greater than 200 mmHg, the smoothness of the gloss adjusting layer is lowered, so that the coverage of the gloss adjusting layer by the ink absorbing layer is lowered and the ink absorbing property is reduced. Affect the uniformity of.

The non-uniform ink absorption due to the deterioration of the coverage of the gloss adjusting layer by the ink absorption layer can be improved by increasing the coating amount of the ink absorption layer. The gloss adjusting layer having a texture and gloss close to that of paper is deteriorated due to an increase in opacity due to the coating thickness of the ink absorbing layer itself, resulting in deterioration of texture, gloss and texture. Therefore, the smoothness of the gloss adjusting layer is 200 mmHg.
The following is preferable.

Further, the coating amount of the ink absorbing layer of the present invention is not particularly limited, but if the coating amount of the ink absorbing layer is less than 10 g / m ^{2 in} terms of Cobb size, a printed product due to ink overflow during ink jet printing. Affect the decline of rank.
The degree of Cobb size is preferably 20 to 40 g / m ² .
Further, if the coating thickness of the ink absorbing layer is remarkably large, the texture, glossiness, and texture of the printing paper to be calibrated by the gloss adjusting layer deteriorate. Therefore, the coating thickness of the ink absorption layer is 40μ.
It is preferable that the degree of muzzle is m or less and the degree of bump size is 10 g / m ² or more.

In the proofreading ink jet recording sheet of the present invention, the gloss adjusting layer and the ink absorbing layer may have a multi-layered structure.

In the present invention, the method for providing the gloss adjusting layer and the ink absorbing layer may be either an on-machine coater or an off-machine coater. For example, conventionally known air knife coater, curtain coater, die coater,
Various devices such as 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, a cast coater, and a size press can be used on-machine or off-machine. Also, after coating,
It is also possible to finish using a calendar device such as a machine calendar, TG calendar, super calendar, and soft calendar.

The support used in the present invention is LB
Chemical pulp such as KP, NBKP, GP, PGW, RM
P, TMP, CTMP, CMP, CGP and other mechanical pulps, DIP and other waste paper pulps and other wood pulps and conventionally known pigments as main components, and binders and sizing agents and fixing agents, retention agents, cationizing agents, papers. Mixing using one or more kinds of various additives such as a strength enhancer, a fourdrinier paper machine,
Base paper manufactured by various machines such as cylinder paper machine, twin wire paper machine, etc., and further, base paper with size press with starch, polyvinyl alcohol, etc. or anchor coat layer, or coat layer on them It also includes coated paper such as art paper, coated paper and cast coated paper. Such a base paper and a coated paper may be provided with the coating layer according to the present invention as they are, or a calender device such as a machine calender, a TG calender or a soft calender may be used for the purpose of controlling the flatness. .

The basis weight of the support used in the present invention is preferably selected so that the thickness after the ink absorbing layer is provided is close to or thicker than the thickness of the target printing paper. This is because a phenomenon such as cockling, which is caused by a large amount of ink used for image formation in inkjet recording, gives an impression different from that of an ordinary printed matter. Therefore, it is preferable to reduce the difference in thickness between the inkjet recording sheet and the printing paper, or rather to make it thicker. A back coat layer may be coated on the opposite surface of the ink absorbing layer sandwiching the support in order to impart curl aptitude, and the pigment contained may be one of the above-mentioned inorganic or organic pigments. White pigments can be used, but tabular pigments and hydrohaloysite are particularly preferable.

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, organic pigments such as carbon black and phthalocyanine, iron oxide, zinc oxide and the like. Coloring pigments of inorganic pigments can be mentioned.

As the solvent of the ink, for example, 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, polypropylene glycol Polyalkylene glycols such as;
The alkylene group such as ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol, thiodiglycol, hexylene glycol, diethylene glycol has 2 to 6 alkylene groups.
Alkylene glycols; lower alkyl ethers of polyhydric alcohols such as glycerin, ethylene glycol methyl ether, diethylene glycol methyl (or ethyl) ether, and triethylene glycol monomethyl ether. 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.

Other additives include, for example, a pH adjusting agent, a sequestering agent, an antioxidant, an antifungal agent, a viscosity adjusting agent, a surface tension adjusting agent, a wetting agent, a surfactant, and an anticorrosive agent. Can be mentioned.

[0052]

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 mass and% by mass, unless otherwise specified.

<Preparation of base paper> 70 parts of LBKP having a freeness of 450 ml CSF, NBKP3 having a freeness of 450 ml CSF
The ratio of light calcium carbonate / heavy calcium carbonate / talc is 30/35 / to 100 parts of wood pulp consisting of 0 parts.
35 parts pigment 5 parts, commercial alkyl ketene dimer 0.1
Parts, commercially available cationic acrylamide 0.03 part, commercially available cationized starch 1.0 part, and sulfuric acid band 0.5 part,
Paper is made with a Fourdrinier paper machine at a basis weight of 105 g / m ² , and commercially available oxidized starch is dried with an Inclined size press to have an adhesion of 5 g.
/ M ² and dried to obtain base paper A.

<Preparation of Paper A for Calibration> Preparation of the coating composition was carried out by using high-white first-class kaolin (Ultra White 9) as a pigment.
0: ENGELHARD) 60 parts, wet finely ground heavy calcium carbonate (carbital 90: ECC Japan) 40 parts, commercially available polyacrylic acid-based dispersant as a pigment dispersant (Aron T-40: Toagosei Co., Ltd.) 0.02 parts, commercial phosphate esterified starch as a binder (MS460
0: manufactured by Nippon Shokuhin Kako Co., Ltd.) and 20 parts of a commercially available styrene-butadiene latex (0693: manufactured by JSR Co.) were used to obtain a solid content of 60%. Next, the composition is coated on a base paper A by a blade coater so that the dry coating amount is 15 g / m ^2, and dried, and then JIS-P is used.
Supercalendering was performed so that the 75-degree specular gloss defined by 8142 was 65%, and a proof sheet A was obtained.

<Preparation of calibration target paper B> Calibration is performed in the same manner as calibration target paper A except that the super calendar is adjusted so that the 75-degree specular gloss defined by JIS-P8142 by super calendar processing becomes 30%. Target paper B was created.

<Preparation of Calibration Target Paper C> As the calibration target paper, a commercially available coated paper (pearl coat: manufactured by Mitsubishi Paper Mills) was used.

<Preparation of Calibration Target Paper D> As the calibration target paper, commercially available mat-coated paper (New V Matt: manufactured by Mitsubishi Paper Mills) was used.

<Preparation of Coating Composition for Gloss Control Layer A> 60 parts of high-white first-class kaolin (Ultra White 90: manufactured by ENGELHARD) as a pigment, wet finely ground heavy calcium carbonate (carbital 90) were prepared as a coating composition. : ECC Japan Co., Ltd.) 40 parts, commercially available polyacrylic acid type dispersant as a pigment dispersant (Aron T-40: Toagosei Co., Ltd.) 0.02
Parts, commercial phosphate esterified starch (MS4 as a binder
600: manufactured by Nippon Shokuhin Kako Co., Ltd.) and 20 parts of a commercially available styrene-butadiene latex (0693: manufactured by JSR Co.) were used to obtain a solid content of 60%.

<Preparation of coating composition for gloss adjusting layer B> 60 parts of high-white first-class kaolin (Ultra White 90: manufactured by ENGELHARD) as a pigment, wet finely ground heavy calcium carbonate (carbital 90) were prepared as a coating composition. : 20 parts by ECC Japan, wet silica (Mizukasil P-78)
A: Mizusawa Chemical Co., Ltd.), 20 parts, commercially available polyacrylic acid-based dispersant as a pigment dispersant (Aron T-40: Toagosei Co., Ltd.)
0.1 part, commercial phosphate esterified starch as a binder (MS4600: made by Nippon Shokubai Co., Ltd.) 5 parts, commercially available styrene-butadiene latex (0693: made by JSR)
20 parts were used and the solid content was adjusted to 50%.

<Preparation of Gloss Adjustment Layer C> A coating layer of a commercially available coated paper (pearl coat: manufactured by Mitsubishi Paper Mills) was used as the gloss adjustment layer C.

<Preparation of gloss adjusting layer D> The coating layer of commercially available coated paper (New V Matt: manufactured by Mitsubishi Paper Mills) was used as the gloss adjusting layer D.

<Preparation of Coating Composition for Ink Absorbing Layer A> Preparation of coating composition was carried out by using gas phase silica (Aerosil 3) as a pigment.
00: manufactured by Nippon Aerosil Co., Ltd.) and 5 parts of a cationic polymer (Charol DC902P: manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) as a pigment dispersant were used to obtain a pigment dispersion having a solid content of 15%. This pigment dispersion is applied to a media mill (Dyno Mill KD
L-PILOT A: manufactured by Shinmaru Enterprises Co., Ltd.) and redispersed so that the secondary particle diameter was 150 nm to obtain a final pigment dispersion liquid. The final pigment dispersion 100
Polyvinyl alcohol (PVA2
35: manufactured by Kuraray Co., Ltd.) and 5 parts of boric acid as a binder aid were used to prepare a coating composition for the ink absorption layer A with a solid content of 10%.

<Preparation of coating composition for ink absorbing layer B> Ink absorbing layer was prepared in the same manner as for preparing coating composition for ink absorbing layer A except that the secondary particle size of vapor phase silica was adjusted to 250 nm. A coating composition B was obtained.

<Preparation of coating composition for ink absorbing layer C> Coating of ink absorbing layer A except that the vapor phase silica was changed to Aerosil 50 (manufactured by Nippon Aerosil Co., Ltd.) and the secondary particle diameter was changed to 250 nm. Ink absorbing layer C is prepared in the same manner as the composition preparation.
To obtain a coating composition.

<Preparation of coating composition for ink absorbing layer D> Boehmite alumina (alumina sol 520:
A coating composition for the ink absorption layer D was obtained in the same manner as in the preparation of the coating composition for the ink absorption layer A, except that the composition was changed to Nissan Chemical Co., Ltd.) and the secondary particle size was changed to 200 nm.

<Preparation of Coating Composition of Ink Absorption Layer E> The coating composition of the ink absorption layer A was colored (TB-500 Ora).
ngeR: made by Dainichiseika Co., Ltd. 0.005 parts, colorant (TB
-910 Yellow FR: Dainichiseika Co., Ltd.) 0.00
A coating composition for the ink absorbing layer E was obtained in the same manner as the coating composition for the ink absorbing layer A except that 5 parts were added.

<Preparation of coating composition for ink absorbing layer F> Coating of ink absorbing layer A except that the vapor phase silica was changed to Aerosil 50 (manufactured by Nippon Aerosil Co., Ltd.) and the secondary particle diameter was changed to 350 nm. Ink absorbing layer F is prepared in the same manner as the composition preparation.
To obtain a coating composition.

Example 1 The coating composition for the gloss adjusting layer A was dried on the above-mentioned base paper A with a blade coater to give a dry coating amount of 1
Coated to 5 g / m ² and dried, then JIS-P8
Supercalendering was performed so that the 75-degree specular gloss defined by 142 was 65%. Then gloss control layer A
The coating composition for the ink absorbing layer A was coated on the above with a comma coater so as to have a dry coating film thickness of 30 μm and dried to prepare an ink jet recording sheet for calibration of Example 1.

<Example 2> An ink jet recording sheet for calibration of Example 2 was prepared in the same manner as in Example 1 except that the ink absorbing layer A was changed to the ink absorbing layer B.

<Example 3> An ink jet recording sheet for calibration of Example 3 was prepared in the same manner as in Example 1 except that the ink absorbing layer A was changed to the ink absorbing layer C.

Example 4 A calibration ink jet recording sheet of Example 4 was prepared in the same manner as in Example 1 except that the ink absorbing layer A was changed to the ink absorbing layer D.

<Example 5> An ink jet recording sheet for calibration of Example 5 was prepared in the same manner as in Example 1 except that the ink absorbing layer A was changed to the ink absorbing layer E.

<Example 6> An ink jet recording sheet for calibration of Example 6 was prepared in the same manner as in Example 1 except that the ink absorbing layer A was changed to the ink absorbing layer C and the coating film thickness was changed to 50 μm. did.

Example 7 JIS-P8 of gloss adjusting layer A
An ink jet recording sheet for calibration of Example 7 was prepared in the same manner as in Example 1 except that the 75 ° specular gloss defined by 142 was adjusted to 30%.

<Example 8> The gloss adjusting layer A was replaced with the gloss adjusting layer B.
And a calibrating inkjet recording sheet of Example 8 was prepared in the same manner as in Example 1 except that the 75-degree specular glossiness defined by JIS-P8142 was adjusted to 30%.

Example 9 The above-mentioned calibration target paper C, that is, the gloss adjusting layer C, was coated with a coating composition of the ink absorbing layer A by a comma coater so that the dry coating amount was 15 g / m ² . It was dried to prepare a calibration inkjet recording sheet of Example 9.

<Example 10> The above-mentioned calibration target paper D, that is, the gloss adjusting layer D, was coated with the coating composition of the ink absorption layer A by a comma coater so that the coating amount was 15 g / m ² and dried. Then, a calibration inkjet recording sheet of Example 10 was prepared.

<Comparative Example 1> An ink jet recording sheet for calibration of Comparative Example 1 was prepared in the same manner as in Example 1 except that the ink absorbing layer A was changed to the ink absorbing layer F.

Comparative Example 2 The ink absorbing layer B was coated on the above-mentioned base paper A with a comma coater so as to have a coating film thickness of 30 μm, dried, and then super-calendered to JIS-P8.
The calibrated inkjet recording sheet of Comparative Example 2 was prepared by adjusting the 75-degree specular gloss defined by 142 to 65%.

[0080]

[Table 1]

Evaluation of Examples 1 to 10 and Comparative Examples 1 and 2 and the printing paper to be calibrated was carried out by the following method, and the results are shown in Table 1. In addition, measurement and evaluation are performed according to JIS-P8.
It was conducted under the environment defined by 111.

1) Specular glossiness of 75 degrees The specular glossiness was obtained by using a gonio gloss meter (VGS-1001DP: manufactured by Nippon Denshoku Co., Ltd.) according to JIS-P8142-1993. The recording sheet was measured.

2) Bristow liquid transfer amount The Bristow test is a test method defined by the Japan Pulp and Paper Institute (J'TAPPI).
PPI No. 51, the amount of liquid transfer at a contact time of 0.5 seconds measured according to the liquid absorption test method for paper and paperboard. As the liquid, a 5% isopropyl alcohol aqueous solution was used.

3) Smoother smoothness The smoothness of the coating layer was measured by a smoother smoothness tester (model SM-6A, manufactured by Toei Denshi Kogyo Co., Ltd.).
(Unit: mmHg)

4) Haze Index A haze value (%) of a transparent polyethylene film having a haze value of 1% measured by the measurement method specified by JIS-K7105 is defined as A, and measured by the measurement method specified by JIS-K7105. Further, an ink absorption layer having a solid content of 10 g / m ² was applied on the transparent polyethylene film having a haze value of 1%, and the haze value (%) after drying was defined as B, and the value was calculated from the following formula (1). Haze index = BA (%) (1) formula

5) Color Index JI of a white PET film having a whiteness of 100% measured according to the measuring method specified in JIS-P8148.
According to the measurement method defined by S-Z8722, the measured values of the lightness index (L *) and the perceived chromaticity index (a *, b *) defined by JIS-Z8729 and JIS-P814
Whiteness 100 measured according to the measurement method specified in 8
% White PET film was coated with an ink absorption layer having a solid content of 10 g / m ² and dried, and then measured according to the measuring method specified in JIS-Z8722.
Lightness index (L *) and perceived chromaticity index (a *,
b *) value of color difference (Δ) specified by JIS-Z8730
E *).

6) Inorganic fine particle secondary particle size Laser particle size analysis system (PAR-
3S: manufactured by Otsuka Electronics Co., Ltd.).

7) Color difference lightness index L * and perceived chromaticity indexes a * and b * are JIS-Z
According to 8722-1995, a color difference meter (CR-20
0: manufactured by Minolta Co., Ltd.) was used to measure the printing paper to be calibrated and the obtained inkjet recording sheet for calibration. The color difference (ΔE *) was calculated for the printing paper to be calibrated.

8) Degree of Cobb Size The measurement was performed according to JIS P8140. The measurement time was 10 seconds, and the measurement solvent was a 5% isopropyl alcohol aqueous solution.

9) Appearance evaluation A solid image of black, cyan, magenta, and yellow and a standard described in JIS-X9201 were applied to the obtained calibration inkjet recording sheet with an inkjet printer (PM-880C: manufactured by Seiko Epson Corporation). Image N3
(Fruit basket) was printed and the appearance as a printed matter was comprehensively evaluated. In the evaluation, the target printing paper was evaluated by comparison with the same printing by offset printing. Those with very few sensory differences were marked with ⊚, those that were perceptually accepted without discomfort were marked with ○, those with a slight difference were marked with △, and those with a very strong difference were marked with ×.

10) Evaluation of texture The feel of the white paper of each recording sheet such as touch, texture, and gloss was visually evaluated. It should be noted that in the evaluation, those with very little sensory difference from the target printing paper are marked with ◎, those that are accepted without a sense of incongruity ○, those with a slight difference △, those with a very strong difference × And

As is clear from the results shown in Table 1, Examples 1 to 1
No. 10 is a proofreading inkjet recording sheet, and the appearance and feel at the time of inkjet printing, which is important as an proofing, can be obtained with a texture very similar to that of the printing paper to be calibrated.

In Comparative Example 1, since the haze index of the ink absorbing layer is larger than 20, the texture with the printing paper to be calibrated, which is important as an inkjet proofing paper, is remarkably deteriorated.

In Comparative Example 2, the color difference and the gloss difference are quite similar to those of the printing paper to be calibrated, but since there is no gloss adjusting layer, the ink absorbency is non-uniform and the appearance during ink jet printing is remarkably deteriorated. . Further, the coating layer composition is largely different from that of the printing paper to be proofed, and the surface quality and glossiness similar to those of the printing paper to be proofed cannot be obtained, and the texture is remarkably deteriorated.

[0095]

As described above, by carrying out the present invention, it is possible to provide an inkjet recording sheet having inkjet suitability suitable for print proofing.

Claims (6)

[Claims] 1. A proofreading inkjet recording sheet comprising a support made of pulp fibers and one or more gloss adjusting layers and one or more ink absorbing layers applied in this order, wherein the gloss adjusting layer contains a white pigment as a total solid content. Of 40% by mass or more, and the haze index of the ink absorption layer defined below is 20% or less. Haze index: A haze value of a transparent polyethylene film having a haze value of 2% or less defined by JIS-K7105 is set to A (%), and an ink absorption layer on the transparent polyethylene film has a solid content of 10 g / m ^2. When the above-mentioned haze value of the applied and dried product is B (%), BA
The value obtained by (%) is defined as the haze index of the ink absorbing layer. 2. The ink jet recording sheet according to claim 1, wherein the color index defined below of the ink absorbing layer is 3 or less. Color index: J of white PET film with whiteness defined by JIS-P8148 of 98 to 110%
Values of lightness index (L *) and perceptibility index (a *, b *) specified by JIS-Z8729 measured by the measuring method specified by IS-Z8722, and the white PET
The above-mentioned lightness index (L *) and perceptibility index (a *, b) measured from the surface of the ink absorption layer of a film obtained by coating and drying the ink absorption layer on the film so that the solid content is 10 g / m ^2.
Color difference (△) specified by JIS-Z8730
E *) is obtained and used as the color index of the ink absorption layer. 3. From the surface of the ink absorbing layer to JIS-Z
JIS measured by the measuring method specified by 8722
-Value of lightness index (L *) and perceptual chromaticity index (a *, b *) specified by Z8729, and 75-degree specular gloss (Gs) specified by JIS-P8142, and printing paper to be calibrated Above, the lightness index (L *) and the perceived chromaticity index (a *,
b *) value and 75 specified by JIS-P8142
JIS-Z8730 obtained from degree of specular gloss (Gs)
3. The color difference (ΔE *) defined by 1 is 3 or less, and the absolute value (| ΔGs |) of the 75-degree specular gloss difference is 15 or less. Inkjet recording sheet for proofreading. 4. The ink absorbing layer has an average primary particle diameter of 50 nm or less and an average secondary particle diameter of 300 nm.
The following inorganic fine particles and a hydrophilic binder are contained, and the solid content ratio of the hydrophilic binder to the inorganic fine particles is 5 to 40% by mass.
The inkjet recording sheet for calibration according to any one of 2 and 3. 5. The smoothing smoothness of the gloss adjusting layer is 200 mmHg or less, and the liquid transfer amount at a contact time of 0.5 seconds measured by the Bristow method is 10 g / m ² or less. Any one of 2, 3, and 4
An inkjet recording sheet for calibration according to the item. 6. The coating thickness of the ink absorbing layer is 40 μm.
m or less, JIS-P81 from the surface of the ink absorption layer
The calibration inkjet recording sheet according to any one of claims 1, 2, 3, 4 and 5, wherein the degree of Cobb size defined by 40 is 10 g / m ² or more.