JP4840120B2 - Inkjet recording sheet manufacturing method - Google Patents

Description

  The present invention relates to a method for producing a recording sheet applied to an ink jet recording system.

Ink jet recording method in which water-based ink is ejected from a fine nozzle toward a recording sheet and an image is formed on the recording surface of the sheet has less noise during recording, and it is easy to form a full-color image. It is widely used in terminal printers, facsimiles, plotters, form printing, and the like due to the fact that high-speed recording is possible and the recording cost is lower than other printing apparatuses.
On the other hand, due to the rapid spread of printers, high definition and high speed, and the advent of digital cameras, the characteristics of ink jet recording sheets are also required to be enhanced. That is, there is a strong demand for an ink jet recording sheet that has excellent ink absorption, recording density, water resistance, and light resistance, and has image quality, gloss, and storability comparable to silver salt photography. Furthermore, it is also required to prevent cracking and cracking of the ink receiving layer in the ink jet recording sheet.
Furthermore, with the widespread use of inkjet recording systems, there is an increasing demand for inkjet recording sheets having a moderate glossiness and a relatively low cost, that is, inkjet recording sheets with excellent cost performance.

The ink jet recording sheet in which the ink receiving layer containing fine particles is coated on the support has good ink absorbability, and the ink receiving layer made of fine particles has high transparency, so the color of the ink is clear. High print density can be obtained. Further, the ink receiving layer made of fine particles has excellent surface smoothness and appropriate gloss even without gloss treatment by the casting method, and meets the above market demand.
However, simply applying an ink-receiving layer containing fine particles on the support causes the coating layer to shrink and crack easily when drying in the coating drying process, resulting in poor smoothness. As a result, there is a problem that glossiness is lowered, blurring is generated along the cracks during printing, or uniformity of printing is lowered. In order to prevent cracking, the binder component of the ink receiving layer can be increased. However, this method also reduces the ink absorption speed of the ink receiving layer, so that the ink ejected from the printer cannot be absorbed immediately. In addition, there is a problem in that printing blur occurs and print quality is deteriorated.
In addition, when the coating amount of the ink receiving layer is increased, there is a disadvantage that the completed inkjet recording sheet becomes thicker or becomes stiff and easily broken.
For this reason, after applying a treatment liquid containing a material having a function of gelling or thickening in contact with a coating liquid for forming an ink receiving layer on a support in advance, an ink receiving layer is provided, thereby providing an ink receiving layer. A method for preventing the occurrence of cracks in the layer has already been proposed.

Patent Document 1 includes a pigment mainly composed of synthetic silica and a binder mainly composed of polyvinyl alcohol on one surface of a base paper obtained by coating borax or boric acid at least 0.1 g / m ² per side. An ink jet recording paper having an ink receiving layer formed thereon is disclosed. However, the combination of pigments mainly composed of synthetic silica and polyvinyl alcohol makes the pigment particles large and irregular, making it difficult to obtain gloss, and if the uniformity of print quality decreases due to uneven penetration of borax or boric acid. There was a problem.
Patent Document 2 discloses a porous material containing boehmite and polyvinyl alcohol on a treated surface of a substrate surface-treated with at least one selected from the group consisting of boric acid and borate and a paper surface treating agent. A recording sheet having an ink absorbing layer is disclosed.
Patent Document 3 discloses that in an inkjet recording sheet having a color material receiving layer on a support, boric acid or a boron compound is supported on at least the support between the support and the color material receiving layer. The surface is coated with 0.1 g / m ² or more per surface, and the colorant-receiving layer comprises inorganic pigment fine particles having an average primary particle diameter of 20 nm or less and a water-soluble resin, and has a porosity of 50 to 80%. An ink jet recording sheet having the following three-dimensional network structure is disclosed.
Patent Document 4 also describes: a) an undercoat layer comprising a polymer binder and a borate or borate derivative, wherein the borate or borate derivative is present in an amount of ³ to 50 g / m ² , and An undercoat layer in which the mass ratio of the polymeric binder to the borate or borate derivative is 0.2: 1 to 2: 1; and b) an image-receiving layer comprising a crosslinkable polymer and particles containing hydroxyl groups. An image receiving layer, wherein the crosslinkable polymer is present in an amount of ²⁰ to 150 g / m ² and the mass ratio of the crosslinkable polymer to the particles is 10:90 to 30:70. An ink jet recording element comprising a substrate is disclosed.
Patent Document 5 discloses an ink receiving layer and a cast layer in which a crosslinking agent is applied to a support or an undercoat layer formed on the support, and a pigment and a binder that crosslinks the crosslinking agent are applied. An inkjet recording body to be formed is disclosed.

Although these methods prevent the ink-receiving layer from penetrating into the air-permeable support, the cross-linking agent-containing liquid coated on the air-permeable support penetrates into the support, resulting in necessary gelation or thickening. There was a problem if the function to perform was not demonstrated. In particular, when a cross-linking agent-containing liquid is applied on the pigment coating layer, unevenness in the penetrating state of the cross-linking agent-containing liquid can be caused by unevenness in the size of the paper and non-uniformity in the pigment coating layer. As a result, there are problems such as ink absorbability of the ink receiving layer and uneven printing quality (for example, when printing on the entire surface of ink jet recording paper, uniformity of printing density cannot be obtained).
When such an ink receiving layer was cast-finished or a glossy expression layer was further formed by a casting method, although ink was exhibited, unevenness in ink absorbability and print quality occurred.
Japanese Patent Publication No. 7-37175 JP 11-291621 A JP 2001-246832 A JP 2003-205679 A JP 2006-142748 A

  An object of the present invention is to provide an ink-jet recording sheet in which an ink-receiving layer containing fine particles is coated on a support, which provides excellent ink absorption, high print density, and gloss treatment by a casting method. Thus, an object of the present invention is to provide a method for producing an inkjet recording sheet having surface smoothness and gloss comparable to silver salt photographic printing paper.

  In order to solve the above-mentioned problems, the inventors have conducted extensive research, and as a result, a crosslinking agent and a viscosity having an action of gelling or thickening on the ink-absorbing layer in contact with the coating liquid for forming the ink-receiving layer. The present inventors have found that the above problems can be solved by applying a crosslinking agent-containing treatment liquid having a viscosity of 2 mPas to 20 mPas (B-type viscometer) in which the adjusting agent is blended, and the present invention has been completed.

That is, the present invention
(1) In a method for producing an inkjet recording sheet having at least an ink absorbing layer and an ink receiving layer on a support, a first step of providing an ink absorbing layer on at least one surface of the support, the ink absorption A second step of coating a layer with a material having an action of gelling or thickening upon contact with the ink-receiving layer-forming coating liquid and a crosslinking agent-containing liquid containing a cellulose derivative as a viscosity modifier. And a third step of applying an ink receiving layer containing at least fine particles having an average particle size of 5 nm or more and 700 nm or less.
(2) cellulose derivative as a viscosity modifier, cationized cellulose, carboxymethyl cellulose, hydroxyethyl cellulose and is hydroxypropylmethylcellulose row scan or Ranaru one or more selected from the group (1) of the ink jet recording sheet according to Production method.
(3) the viscosity of the crosslinking agent-containing solution is a Lee inkjet recording sheet manufacturing method according to a 2MPas～20mPas (B type viscometer) (1) or (2).
(4) The crosslinking agent contained in the crosslinking agent-containing liquid is boric acid and / or borax, and the ink-receiving layer-forming coating liquid contains polyvinyl alcohol (1) to ( 3) The method for producing an inkjet recording sheet according to any one of 3) .
(5) The method for producing an inkjet recording sheet according to any one of (1) to (4) , wherein the crosslinking agent-containing liquid contains a surfactant.
(6) After coating the ink-receiving layer, characterized in that it comprises a fourth step of applying a glossy layer containing the following colloidal particles 100nm least an average particle diameter of 5nm or more (1) - ( 5) The method for producing an inkjet recording sheet according to any one of 5) .

  The method for producing an ink jet recording sheet of the present invention is excellent in ink absorbency, obtains a high printing density, and has a surface smoothness comparable to silver salt photographic printing paper by applying gloss treatment by a casting method. A glossy inkjet recording sheet can be obtained.

<First step>
In the present invention, as a first step, an ink absorbing layer is provided on a support.

"About support"
The support used for the ink jet recording sheet is not particularly limited with respect to its type, shape, dimensions, etc., but both an absorbent support and a non-absorbent support can be used. The non-absorbent support base material is preferable from the viewpoint of cockling (waving) after printing and photographic texture, but if ink absorption is insufficient, blurring occurs during ink jet recording. Inconvenience may occur.

(Absorbent support)
Examples of the absorbent support include paper substrates such as high-quality paper, medium-quality paper, coated paper, art paper, and cast-coated paper. Examples of the paper base material include wood pulp as a main component, and additives containing additives such as fillers and various auxiliary agents as necessary.
As the wood pulp, various chemical pulps, mechanical pulps, recycled pulps and the like can be used. These pulps can be adjusted by a beating machine in order to adjust paper strength, papermaking suitability, and the like. The beating degree (freeness) of the pulp is not particularly limited, but is generally about 250 to 550 ml (CSF: JIS-P-8121). In order to improve smoothness, it is desirable to advance the beating degree. However, when recorded on paper, paper blur and recording image bleeding caused by moisture in the ink often gives better results if the beating is not advanced. . Accordingly, the freeness is preferably about 300 to 500 ml.

The filler is blended for the purpose of imparting opacity or adjusting the ink absorbability, and calcium carbonate, calcined kaolin, silica, titanium oxide and the like can be used. In particular, calcium carbonate is preferable because it becomes a paper base material with high whiteness and glossiness of ink jet recording paper is enhanced. The content (ash content) of the filler in the paper substrate is preferably about 1 to 20% by mass, and if it is too much, the paper strength may be reduced. If the amount is too small, the air permeability of the paper base material is deteriorated, so the preferable filler content is 7 to 20% by mass. Within this range, smoothness, air permeability, and paper strength are balanced, and as a result, an inkjet recording sheet excellent in glossiness and image sharpness is easily obtained.
A sizing agent, a fixing agent, a paper strength enhancer, a cationizing agent, a yield improving agent, a dye, a fluorescent brightening agent, and the like can be added to the paper base as an auxiliary agent. As the paper strength enhancer, a paper strength enhancer such as polyamide / epichlorohydrin resin, N-vinylformamide / vinylamine copolymer, or the like may be added, applied or impregnated. In particular, polyamide epichlorohydrin resin is preferably used because it has an effect of improving the dimensional stability of paper when wet.

Furthermore, starch, polyvinyl alcohol, cationic resin, etc. can be applied and impregnated on the paper base material in the size press process of the paper machine to adjust the surface strength, sizing degree, and the like.
If the paper substrate does not have the ability to absorb water, the coating of the ink-absorbing layer (undercoat layer) is applied to the paper substrate. Therefore, there is a problem that a long time is required for the drying process, or a coating surface defect called wind ripples occurs in the wind in the dryer.
On the other hand, when the ability to absorb water is too high (that is, when the sizing degree of the paper base material is low), there may be operational problems such as wrinkles generated during coating. Further, when the sizing degree is high, the ink absorbability may be lowered, and curling and cockling after printing may be remarkable. A more preferable range of the sizing degree is 5 to 500 seconds in terms of the Steecht sizing degree. The Kobusaizu degree, it preferably 20ml / m ² ~500ml / m ² for the same reason.

(Non-absorbable support)
On the other hand, examples of the non-absorbent support include plastic films such as polyethylene terephthalate, polyvinyl chloride, polycarbonate, polyethylene, and polypropylene, synthetic paper, and white films. Moreover, you may use the non-absorbent resin coating sheet etc. which are obtained by coat | covering these support bodies and the said absorptive support body with non-ink medium absorbent resin. As the non-ink medium-absorbing resin, a polyolefin resin such as polyethylene and polypropylene, a cellulose diacetate resin, a polyester resin, or a mixture thereof can be used as a main component. It is preferable because of good adhesion, and polyethylene is particularly preferable.

  In addition, the surface of the support on which the ink receiving layer is formed may be subjected to an adhesion treatment or an adhesion treatment in advance for the purpose of improving the adhesion between the support and the ink receiving layer. In particular, when resin-coated paper is used as the non-absorbent support, it is preferable to subject the surface of the resin coating layer to corona discharge treatment or to provide an undercoat layer made of gelatin, polyvinyl alcohol or the like.

  It is also possible to perform processing such as transportability improvement processing, antistatic processing, and antiblocking processing on the back surface of the support. The back surface treatment may be, for example, a chemical treatment such as an antistatic agent and an antiblocking agent, or may be another one appropriately added such as providing a coat layer.

  The smoothness of the support is not particularly limited, but if the Oken type smoothness (Oken type, J.TAPPI No. 5) is 300 seconds or more, a highly glossy and highly smooth surface can be obtained. . Further, the opacity of the support is not particularly limited, but it is preferable that the opacity (JIS P8138) is 85% or more and a silver salt photograph-like appearance (particularly visual whiteness) can be obtained. More preferably, it is 93% or more.

(Other support)
Depending on the forming method of the coating layer (ink absorption layer, ink receiving layer, glossy expression layer) formed thereon or the application used, etc. It can be appropriately selected and used. Of course, a layer for adjusting the color by a fluorescent dye, a fluorescent pigment or the like may be formed on the support surface, an antistatic layer, an anchor layer or a barrier layer may be formed, or a corona treatment may be applied. Also, for the purpose of preventing curling during printing, adjusting friction, improving printer transportability, and adjusting touch, texture, etc., a back layer containing a resin and, if necessary, a pigment or dye may be provided. it can. A backside treatment layer can be provided for the purpose of improving transportability in the printer.

About the ink absorption layer
An ink absorbing layer is formed on the support. By forming the ink absorbing layer, it is possible to suitably adjust the ink absorbency when printing with an ink jet printer, and the printability such as print density, print bleeding, and solid uniformity tends to be improved. The ink absorption layer is a layer having a function of quickly absorbing the solvent component of the ink, and preferably contains a pigment and an adhesive.

(About pigments)
Examples of pigments incorporated in the ink absorption layer (undercoat layer) include kaolin, clay, calcined clay, amorphous silica (also referred to as amorphous silica), synthetic amorphous silica, zinc oxide, aluminum oxide, titanium oxide, and water. Aluminum oxide, calcium carbonate, satin white, aluminum silicate, alumina, colloidal silica, zeolite, synthetic zeolite, sepiolite, smectite, synthetic smectite, magnesium silicate, magnesium carbonate, magnesium oxide, diatomaceous earth, styrene plastic pigment, hydrotalcite, urea One or more of various publicly known pigments in the general coated paper manufacturing field, such as resin-based plastic pigments and benzoguanamine-based plastic pigments, can be used in combination. Among these, zinc oxide, titanium oxide, and plastic pigments are preferably blended because yellowing of the white paper portion can be prevented. Amorphous silica, alumina, and zeolite are preferably contained as main components because they have high ink absorbability.

The average particle diameter of the pigment (aggregated particle diameter in the case of an agglomerated pigment) is preferably about 1 to 12 μm, more preferably 2 to 10 μm, and further preferably 2 to 6 μm. By setting it to 1 μm or more, an effect of improving the ink absorption rate can be obtained, and by setting it to 12 μm or less, it is possible to prevent the smoothness and gloss of the ink receiving layer from being lowered. It is also possible to use pigments having different average particle sizes in combination.
Also, for the purpose of adjusting the ink absorptivity or controlling the penetration of the crosslinking agent-containing liquid applied to the ink absorbing layer or the coating liquid for the ink receiving layer, as an accessory component, the average particle size is small. For example, a pigment having an average particle diameter of less than 1 μm can be blended. Examples of such pigments include colloidal silica and alumina sol, and colloidal silica is particularly preferable.

(About adhesive)
Adhesives blended in the ink absorbing layer include proteins such as casein, soy protein, and synthetic protein, various starches such as starch and oxidized starch, polyvinyl alcohol, cationic polyvinyl alcohol, and modified polyvinyl alcohol such as silyl-modified polyvinyl alcohol. Polyvinyl alcohols containing alcohol, cellulose derivatives such as carboxymethyl cellulose and methyl cellulose, styrene-butadiene copolymer, conjugated diene polymer latex of methyl methacrylate-butadiene copolymer, acrylic polymer latex, ethylene-vinyl acetate copolymer Conventionally known adhesives generally used for coated paper, such as vinyl polymer latex such as coalescence, aqueous polyurethane resin, and aqueous polyester resin, are used alone or in combination.
The aqueous polyurethane resin is also commonly called urethane emulsion, urethane latex, polyurethane latex and the like. The polyurethane resin is obtained from a reaction between a polyisocyanate compound and an active hydrogen-containing compound. It is a polymer compound containing a relatively large number of urethane bonds and urea bonds.
The blending ratio of the pigment and the adhesive is generally adjusted in the range of 1 to 100 parts by weight, preferably 2 to 50 parts by weight with respect to 100 parts by weight of the pigment, although it depends on the type.

(Other ink absorption layers)
In the ink absorption layer (undercoat layer), various auxiliary agents such as a dispersant, a thickener, an antifoaming agent, an antistatic agent, and an antiseptic used in the production of general coated paper are appropriately added. Further, a fluorescent dye and a colorant can be added to the undercoat layer.

(About formation of ink absorption layer)
The ink absorbing layer can be formed by applying an undercoat layer coating solution composed of the above material onto a support and drying. The ink absorbing layer coating liquid is applied with a solid content concentration adjusted to about 5 to 50% by mass.
The coating amount of the ink absorbing layer coating solution, by dry weight, preferably 2~60g / m ^2, more preferably 2 to 30 g / m ² approximately, more preferably 4~20g / m ² approximately. By setting the coating amount to 2 g / m ² or more, the ink absorption improvement effect can be sufficiently obtained, and excellent glossiness can be obtained when the ink receiving layer is provided, and by setting it to 60 g / m ² or less. There is a tendency that the printing density is increased, the strength of the coating layer is improved, and powder falls and scratches are less likely to occur.

For coating of the ink absorbing layer coating solution, blade coater, air knife coater, roll coater, brush coater, Champlex coater, bar coater, lip coater, gravure coater, curtain coater, slot die coater, slide coater, etc. Various publicly known coating apparatuses can be used.
Further, after the ink absorbing layer is formed, a smoothing process such as super calendering or brushing can be performed as necessary. Two or more undercoat layers may be formed.

<Second step>
After the ink absorbing layer is provided on the support by the first step, the second step is to act on the ink absorbing layer to gel or thicken in contact with the ink receiving layer forming coating solution. A crosslinker-containing liquid containing a material having a viscosity (hereinafter also referred to as a crosslinker) and a viscosity modifier is applied. Alternatively, as the second step, a crosslinking agent-containing liquid containing a crosslinking agent and having a viscosity of 2 mPas to 20 mPas (B-type viscometer) is applied onto the ink absorbing layer.

[Crosslinking agent-containing liquid]
The crosslinking agent-containing liquid contains at least one material that gels or thickens in contact with the ink-receiving layer-forming coating liquid. The first invention includes one or more viscosity modifiers that can be adjusted by increasing the viscosity of the crosslinking agent-containing liquid. 2nd invention prescribes | regulates the viscosity of a crosslinking agent containing liquid. It is more preferable to use a surfactant in combination with the cross-linking agent-containing liquid because a further effect is exhibited.

[About cross-linking agent]
Examples of the material (crosslinking agent) having an action of gelling or thickening upon contact with the ink receiving layer forming coating solution include a boron compound, an epoxy compound, a glycidyl compound, a zirconium compound, an aluminum compound, a chromium compound, and the like. Can be mentioned. Among these, when combined with polyvinyl alcohol as a water-soluble resin to be described later, a boron compound is preferable, and boric acid and / or borax are more preferable because of progress of gelation or thickening.
Examples of boric acid include orthoboric acid, metaboric acid, hypoboric acid, tetraboric acid, and pentaboric acid. Moreover, these sodium salt, potassium salt, and ammonium salt may be sufficient. Among these, orthoboric acid and disodium tetraborate are preferable.
Borax is a hydrous borate mineral of sodium, and its composition is Na ₂ B ₄ O ₇ · 10H ₂ O. Essentially Na ₂ B ₄ O ₇ (disodium tetraborate) is the crosslinker component.
It is preferable that the density | concentration of a crosslinking agent is 0.001-20 mass%. If it is 0.001 mass% or more, the water-soluble resin used for the ink receiving layer described later can be sufficiently gelled or thickened by the crosslinking agent. On the other hand, if it is 20 mass% or less, excessive gelation or thickening can be prevented.

[Viscosity modifier]
The viscosity modifier may be one that the viscosity of the crosslinking agent-containing solution is increased by addition of this, such as gelatin, Baiogamu, cellulose derivatives, guar gums, sodium alginate, polyacrylic acid and the like.
Examples of the biogum include xanthan gum, welan gum, and gellan gum. Examples of the cellulose derivative include cationized cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, hydroxypropyl cellulose, ethyl cellulose and the like. Examples of guar gums include guar gum, hydroxypropylated guar gum, and cationized guar gum.

In the present invention, the viscosity modifier uses a cellulose derivative in view of balance because the viscosity of the crosslinking agent-containing liquid is relatively high .
The degree of polymerization of the cellulose derivative is preferably 500 to 2000, and more preferably 800 to 1800 in that the viscosity adjustment of the crosslinking agent-containing liquid is relatively easy.
In the present invention, the content of the viscosity modifier in the crosslinking agent-containing coating solution is set so that the viscosity of the crosslinking agent-containing coating solution is in a desired range, and is not particularly limited, but reaches the desired viscosity with a small amount of addition. In this case, it is not preferable because fine adjustment of the viscosity is difficult. On the other hand, if the addition amount of the viscosity modifier is too large, the ink absorbability is lowered. Therefore, it is preferable to use within the range of 1-100 mass parts with respect to 100 mass parts of crosslinking agents, for example.

[Viscosity of crosslinking agent-containing liquid]
The viscosity of the crosslinking agent-containing liquid is 2 mPas to 20 mPas. Furthermore, it is preferably 5 mPas to 10 mPas. This viscosity is a value obtained by measurement using a “B-type viscometer BL type” manufactured by Toki Sangyo Co., Ltd. under conditions of a liquid temperature of 23 ° C. and 60 rpm. When the viscosity of the cross-linking agent-containing liquid is less than 2 mPas, it is difficult to uniformly apply the cross-linking agent-containing liquid to the ink absorption layer, and the penetration into the ink absorption layer is likely to be uneven and uneven coating is likely to occur. Inconvenience occurs. On the other hand, if it exceeds 20 mPas, the cross-linking agent-containing liquid does not easily penetrate from the surface of the ink absorbing layer, and when applying the ink receiving layer continuously, a waiting time is required until coating. The speed is reduced, or the line of the coating device needs to be lengthened. Alternatively, even when the ink receiving layer is applied after winding and storing the support, there is a problem that it takes a long time to dry and productivity is lowered. More preferably, it is 5 mPas or more and 10 mPas.
Although the adjustment method of a viscosity is not specifically limited, It is preferable to use the said viscosity modifier.

[Surfactant]
By adding a surfactant to the cross-linking agent-containing liquid, the repellency of the cross-linking agent-containing liquid on the surface of the support can be suppressed. Therefore, even when the viscosity of the treatment liquid increases due to the addition of a viscosity modifier, the coating uniformity Can be secured.
As the surfactant, any of an anionic surfactant, a cationic surfactant, and a nonionic surfactant may be used.
Examples of anionic surfactants include sulfate ester salts, sulfonate salts, phosphate ester salts, and the like.
Examples of the cationic surfactant include amine salt type and quaternary ammonium salt type.
Nonionic surfactants include, for example, acetylene glycols, polyethylene glycols (higher alcohol ethylene oxide adducts, fatty acid ethylene oxide adducts, alkylphenol ethylene oxide adducts, polypropylene glycol ethylene oxide adducts, higher aliphatic amines and fatty acids. Amide ethylene oxide adducts, etc.), polyhydric alcohols (glycerin and pentaerythritol fatty acid esters, sorbitol and sorbitan fatty acid esters, sucrose fatty acid esters, polyhydric alcohol ethylene oxide adducts, fatty acid alkanolamides), etc. Can be mentioned.

  Among the above surfactants, nonionic surfactants are preferred because of their high affinity with ink for ink jet printers. Furthermore, among nonionic surfactants, acetylene glycol surfactants are preferred. The acetylene glycol-based surfactant is nonionic and has a very strong polarity because oxygen atoms are bonded to adjacent carbon atoms that form an acetylenic triple bond in the molecule. Therefore, even when added in a small amount, the surface activity effect is high, and the wettability of the treatment liquid on the support surface can be improved. In general, a surfactant has a strong bubble forming property, which causes a problem of foaming. However, an acetylene glycol surfactant has a defoaming property and can suppress foaming.

  The acetylene glycol surfactant is a compound having an acetylene bond and an alcoholic hydroxyl group in the molecule, and among them, an addition reaction product of an alkynylene glycol compound and ethylene oxide is preferable. A particularly preferred acetylene glycol surfactant is a compound obtained by adding ethylene oxide to 2,4,7,9-tetramethyl-5-decyne-4,7-diol, and is represented by the following formula (1). A compound having a chemical structure. In particular, in the formula (1), m + n is preferably 6 or less, and m + n is more preferably 2 to 5. Although m and n are integers, the average value may of course not be an integer.

  The surfactant content in the crosslinking agent-containing liquid is preferably 0.001 to 10 parts by mass with respect to 100 parts by mass of the crosslinking agent. When the content of the surfactant is 0.001 part by mass or more with respect to 100 parts by mass of the crosslinking agent, the wettability of the crosslinking agent-containing coating solution with respect to the support surface can be sufficiently ensured. On the other hand, if it is 10 parts by mass or less, problems such as blocking after coating and transfer to the back surface are unlikely to occur.

  The crosslinking agent-containing liquid may contain a solvent as appropriate. The crosslinking agent-containing liquid is prepared by mixing, for example, a crosslinking agent solution in which a crosslinking agent is dissolved in a solvent, a surfactant solution in which a surfactant is dissolved in a solvent, and a viscosity adjusting agent solution in which a viscosity modifier is dissolved in a solvent. It is prepared by. Examples of the solvent include water or an aqueous solvent obtained by adding a small amount of an organic solvent to water.

[Coating method]
Examples of the means for applying the crosslinking agent-containing liquid to the ink absorbing layer include a blade coater, an air knife coater, a roll coater, a bar coater, a gravure coater, a rod blade coater, a lip coater, a die coater, a curtain coater, and a slide bead coater. Is mentioned.
The crosslinking agent-containing liquid is preferably applied so that the coating amount of the crosslinking agent is 0.1 to 3.0 g / m ^{2 in} terms of solid content. If the coating amount is 0.1 g / m ² or more, the strength of the ink receiving layer can be secured. On the other hand, if the coating amount is 3.0 g / m ² or less, excessive crosslinking of the water-soluble resin can be prevented, and the ink receiving layer can be prevented from cracking.

[Drying method]
After coating the crosslinker-containing liquid on the ink absorbing layer, it is preferable to perform a drying step in which the solvent in the coating liquid is positively removed. After drying, it may be wound up and stored. The ink-receiving layer-forming coating solution can be applied on the coated cross-linking agent-containing solution without drying, but in this case, the ink-receiving layer is immediately applied after the ink-receiving layer-forming coating solution is applied. Since the water-soluble resin therein is crosslinked, for example, when a die coater is used as a coating means for forming the ink-receiving layer-forming coating solution, it may be difficult to perform the coating appropriately because the crosslinked product tends to clog the head. The drying method is not particularly limited, and for example, drying by hot air, drying by infrared irradiation, and the like can be applied.

<Third step>
In the third step, an ink receiving layer containing at least fine particles having an average particle diameter of 5 nm or more and 700 nm or less is applied to the surface coated with the crosslinking agent-containing liquid. The ink receiving layer contains, in addition to fine particles, a water-soluble resin that can be gelled or thickened by contacting with the crosslinking agent as a binder.

[Fine particles]
As fine particles, for example, amorphous silica (including synthetic amorphous silica produced by a wet method and a dry method, and cation-modified silica such as alumina), amorphous silica and a cationic compound are mixed and agglomerated. Amorphous silica-cationic compound aggregate particles obtained by making kaolin, clay, calcined clay, zinc oxide, tin oxide, titanium oxide, magnesium sulfate, aluminum hydroxide, alumina and alumina hydrate, calcium carbonate, Examples include satin white, aluminum silicate, smectite, zeolite, magnesium silicate, magnesium carbonate, magnesium oxide, diatomaceous earth, styrene plastic pigment, urea resin plastic pigment, and benzoguanamine plastic pigment. Among these, amorphous silica and an amorphous silica-cationic compound aggregate obtained by mixing and aggregating amorphous silica and a cationic compound from the viewpoint of easy balance between glossiness and ink absorbability It is preferable to use particles, aluminosilicate, alumina, or alumina hydrate.

  Fine particles used in the ink receiving layer have an average particle size of 5 nm or more and 700 nm or less. Glossiness is excellent when the thickness is 700 nm or less, and ink absorbability is excellent when the thickness is 5 nm or more. The average particle diameter is the diameter of the primary particles when present in the coating liquid as primary particles, and the diameter of the secondary particles when present in the coating liquid as secondary particles in which primary particles are aggregated. . Adjustment of the average particle diameter (average secondary particle diameter) of the secondary particles can be performed by, for example, a method of applying a strong force by mechanical means, a so-called breaking down method (a method of subdividing a bulk material). The mechanical means include ultrasonic homogenizer, pressure homogenizer, liquid flow collision homogenizer, high-speed rotary mill, roller mill, container drive medium mill, medium agitation mill, jet mill, mortar, and crusher (coating in a bowl-shaped container). A device for grinding and kneading the pulverized product with a bowl-shaped stirring bar), a sand grinder, a nanomizer and the like. In order to reduce the particle size, classification and pulverization can be repeated.

[Water-soluble resin]
Examples of water-soluble resins that can be gelled or thickened in contact with the crosslinking agent include, for example, polyvinyl alcohol, cation-modified polyvinyl alcohol, silyl-modified polyvinyl alcohol, polyvinyl acetal, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, casein, soybean protein, Examples include synthetic proteins, starch, polypropylene oxide, polyethylene glycol, polyvinyl ether, polyvinyl acrylamide, and polyvinyl pyrrolidone.
Among these, polyvinyl alcohol is preferable from the viewpoint of ink absorbability, water resistance, and prevention of cracks. The polyvinyl alcohol preferably has a degree of polymerization of 3000 to 5000. If the degree of polymerization is less than 3000, the resulting ink-receiving layer tends to have insufficient water resistance, and those exceeding 5000 are practically difficult to obtain.
The water-soluble resin is preferably used in the range of 1 to 100 parts by mass, more preferably 5 to 50 parts by mass with respect to 100 parts by mass of the fine particles.
The mass ratio of the water-soluble resin and the crosslinking agent is preferably 20: 1 to 1:20, and more preferably 10: 1 to 1:10. By setting the mass ratio within this range, an ink jet recording sheet can be obtained which is superior in crack prevention, aging resistance and ink absorbability.

The coating amount of the ink receiving layer is in the range of 5 to 50 g / m ^2. If the amount is less than 5 g / m ² , the ejected ink cannot be absorbed, and there is a disadvantage that the print is blurred or bleeds. On the other hand, if it exceeds 50 g / m ^{2, the} resulting recording sheet not only becomes thicker, but also causes problems such as an increase in curl and a rigid and inferior folding of the sheet. The preferred range is in the range of 10 to 40 g / m ^2. If the ink receiving layer of the present invention exhibits the same function, two or more layers may be divided and applied.

[Other ingredients]
In the ink-receiving layer-forming coating liquid, within the range where the object of the present invention is achieved,
For example, water dispersible resin (for example, styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer conjugated diene polymer latex, isoprene, neoprene (registered trademark), polybutadienes such as polybutadiene, acrylic polymer latex, etc. , Polybutenes, polyisobutylene, polypropylene, polyalkenes such as polyethylene, vinyl halides, vinyl acetate, styrene, (meth) acrylic acid, (meth) acrylic acid esters, (meth) acrylamide, methyl vinyl ether and other vinyl polymers and co-polymers Includes various adhesives commonly used in the field of coated paper, such as polymer latex, polyurethane resin, polyester resin, polyamide resin, olefin-maleic anhydride resin, melamine resin, etc.) It may be.

The ink receiving layer forming coating liquid may contain a cationic compound. Examples of the cationic compound include polyalkylene polyamines such as polyethylene amine and polypropylene polyamine, or derivatives thereof, acrylic resins having a tertiary amino group or a quaternary ammonium group, and diacrylamine. As content of a cationic compound, it is preferable that it is 1-30 mass parts with respect to 100 mass parts of fine particles, and it is more preferable that it is 5-20 mass parts.
Furthermore, the coating liquid for forming the ink receiving layer may contain various auxiliary agents such as various dispersants, thickeners, antifoaming agents, colorants, antistatic agents and preservatives.

[Coating method, drying method]
As the coating method and the drying method of the ink receiving layer forming coating solution, the same methods as the coating method and the drying method of the crosslinking agent-containing solution can be applied. In the present invention, even when the ink receiving layer formed on the support is a single layer, good ink absorbability can be obtained, but it is also possible to form an ink receiving layer thereon. .

<4th process>
In order to further increase the gloss, as the fourth step, the ink receiving layer can be finished by a casting method, a gloss developing layer can be provided on the ink receiving layer, and the gloss developing layer can be finished by a casting method.

[Cast method]
The casting method applicable to the ink receiving layer is a finishing method in which the ink receiving layer is pressed onto a heated mirror surface, for example, a mirror drum, and dried while being wet, and the mirror surface is copied onto the coating layer. For example, a wet casting method in which an ink receiving layer is applied and pressed against a mirror drum, and a wet coating method in which an ink receiving layer is applied and dried and then wetted by applying a re-wetting liquid is applied to the mirror drum. Is possible. In addition, since a coating layer is dried with a mirror surface drum, it is suitable when using a gas-permeable support body.

[Glossy expression layer]
In the present invention, in order to increase glossiness, a glossy expression layer containing fine particles may be formed on the ink receiving layer. The fine particles are not particularly limited, but colloidal silica, vapor phase silica, and alumina oxide are preferable because excellent gloss can be obtained.
Since the gloss development layer is mainly intended for gloss development, a dye fixing function is not necessarily required, but fixing properties can be improved by selecting cationic fine particles. As the cationic fine particles, cation-modified colloidal silica, gas phase method silica, alumina oxide, or the like is preferable. Among the alumina oxides, vapor phase method (fumed) alumina oxide is more preferable.

The form of the fine particles is preferably colloidal. Either a monodisperse or an agglomerated particle dispersion may be used, but a monodisperse or an agglomerated particle dispersion having a small particle diameter is mainly preferably used in order to obtain a high printing density and high gloss. It is done. Specifically, it is preferable to select from particles having an average particle diameter of 5 to 100 nm.
The glossy layer may appropriately contain the water-soluble resin as long as it does not impair ink absorbability. Moreover, the above-mentioned cationic compound can also be contained as needed.

As a method for forming the glossy layer, it may be applied on the ink receiving layer by a normal coating means, or may be applied in multiple layers simultaneously with the application of the ink receiving layer.
Further, the ink receiving layer can be formed by applying a casting method obtained by applying a coating liquid for forming a glossy layer containing fine particles and a solvent, and pressing and drying on a heated mirror drum. In order to make it easy to peel off from the mirror drum, various release agents may be appropriately added to the coating liquid for forming the glossy layer. The addition amount of the release agent is preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the fine particles.
In addition, when the air permeability of the support is poor, after applying the coating liquid for forming the gloss layer, it was pressed against the mirror drum while it was in a wet state, and then peeled off from the mirror drum while it was still wet. Further, it may be dried by a drying apparatus in a later process.
Solid coating amount of the glossy layer forming coating solution is preferably within a range from 0.1 to 10 g / m ^2, more preferably ^{0.2~5g / m 2, 0.5~2g / m} 2 and more preferable. When the coating amount is too small, the coating film becomes thin and interference color due to light tends to occur, and the glossiness is also unsatisfactory. On the other hand, if the coating amount is too large, the ink absorption rate is remarkably lowered and the transparency may be lowered.

  The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to these examples. Moreover, unless otherwise indicated, the part and% in an example are a mass part and the mass%, respectively.

<Preparation of support>
(Support)
Beating softwood bleached kraft pulp (NBKP) until the freeness (CSF, JIS P-8121) reaches 250 ml, and hardwood bleached kraft pulp (LBKP) beaten until the freeness reaches 250 ml, a mass ratio of 2: 8 Was mixed to prepare a pulp slurry having a concentration of 0.5%. In this pulp slurry, cationized starch 2.0%, alkyl ketene dimer 0.4%, anionized polyacrylamide resin 0.1%, polyamide polyamine epichlorohydrin resin 0.7%, and internal addition to the pulp dry weight. Light calcium carbonate was added as a filler and dispersed by sufficiently stirring. The amount of light calcium carbonate was adjusted to 5% in terms of the mass ratio of the finished base paper.
The pulp slurry having the above composition was made with a long net machine, and passed through a dryer, a size press, and a machine calendar to produce a base paper having a basis weight of 180 g / m ² and a density of 0.85 g / cm ³ . The size press liquid used in the size press step is prepared by mixing polyvinyl alcohol and oxidized starch at a mass ratio of 1: 3, adding this to water, dissolving by heating, and adjusting the concentration to 5%. The amount of the size press solution absorbed into the base paper was 50 ml / m ² in total on both sides.

<Preparation of fine pigment>
(Silica sol A)
Commercially available vapor phase silica (trade name: Leolosil QS-30, average primary particle size 10 nm, specific surface area 300 m ² / g, manufactured by Tokuyama Corporation) was dispersed in water by a sand mill and then nanomizer (trade name: nanomizer, manufactured by Nanomizer) ) Was repeated, and after classification, a 10% silica dispersion having an average secondary particle size of 80 nm was prepared. To 100 parts of this silica dispersion, 10 parts of diallyldimethylammonium chloride (trade name: Unisense CP-103, manufactured by Senca) was added as a cationic compound to cause aggregation of silica and increase the viscosity of the dispersion. Thereafter, pulverization and dispersion were repeated using a nanomizer again to prepare an 8% dispersion having an average secondary particle size of 300 nm, whereby silica sol A was obtained.

<Example 1>
<First step>
On one side of the support A, the following ink absorbing layer coating solution was applied using an air knife coater so that the coating amount was 8.0 g / m ² in terms of absolute dry weight, It was dried with a 110 ° C. dryer for 1 minute.
(Preparation of ink absorbing layer coating solution)
To 100 parts of synthetic amorphous silica (trade name: Fine Seal X-45, manufactured by Tokuyama Corporation, average secondary particle size: 4.5 μm), 25 parts of silyl-modified polyvinyl alcohol (trade name: R1130, manufactured by Kuraray Co., Ltd.), dispersed Agent (product name: Aron SD-10, manufactured by Toa Gosei Co., Ltd.), 2 parts of fluorescent dye (product name: Whitetex BPS (H), manufactured by Sumitomo Chemical Co., Ltd.), diallyldimethylammonium chloride-acrylamide copolymer (product) (Name: PAS-J-81, manufactured by Nitto Boseki Co., Ltd.) 5 parts of the mixture was dispersed in water to prepare a coating solution for an ink absorbing layer having a solid content concentration of 15%.

<Second step>
On the ink absorbing layer, the following crosslinking agent-containing liquid 1 was coated on a support so as to be 20 g / m ² with a Mayer bar, and dried at a dryer temperature of 100 ° C. for 1 minute. The coating amount at this time was 0.8 g / m ² in terms of solid content.
(Preparation of crosslinker-containing liquid 1)
100 parts of a 5% aqueous solution of borax and 3 parts of a 1% aqueous solution of cationized cellulose (polymerization degree: 1500, trade name: Poise C-150L, manufactured by Kao Corporation) are mixed and stirred, and water is added thereto. A liquid containing a crosslinking agent having a concentration of 3.8% and a viscosity of 5 mPas was prepared.
A 1% aqueous solution of cationized cellulose was prepared as follows. That is, 1 part of cationized cellulose was charged and dispersed in 99 parts of cold water with stirring, and then heated to 50 ° C. with stirring and held for 1 hour. Subsequently, it cooled to room temperature and obtained the 1% cationized cellulose solution.

<Third step>
On the surface coated with the crosslinking agent-containing liquid, the following ink receiving layer forming coating liquid 1 is applied with a die coater so that the coating amount is 22 g / m ^{2 in} terms of solid content, and the dryer temperature is 100 ° C. The ink receiving layer was formed by drying for 2 minutes.
(Preparation of coating liquid 1 for forming an ink receiving layer)
24 parts of 5% polyvinyl alcohol (Kuraray Co., Ltd., trade name: PVA-135H, polymerization degree: 3500, saponification degree: 99% or more) is mixed with 100 parts of silica sol A, and the ink receiving layer has a concentration of 7.2%. Paint 1 was prepared.

<Example 2>
A glossy expression layer was further formed on the ink jet recording sheet of Example 1.
<4th process>
After applying the gloss developing layer coating liquid 1 to the ink receiving layer with a bar coater so that the coating amount is 1.5 g / m ² in terms of solid content, immediately apply it to a mirror drum with a surface temperature of 100 ° C. The ink-jet recording sheet was completed by pressing and drying.
(Preparation of coating liquid 1 for glossy layer)
Anionic colloidal silica having an average particle size of 0.05 μm (trade name: Snowtex OL, manufactured by Nissan Chemical Industries, Ltd.) 100 parts (colloidal particles), 5% polyvinyl alcohol (manufactured by Kuraray Co., Ltd., product name: PVA-217) , Polymerization degree 1700, saponification degree 88% or more) 10 parts, release agent (polyethylene wax, nonionic) 1 part. Solid concentration 15%.

<Examples 3 to 8 >
An ink jet recording sheet was completed in the same manner as in Example 2 except that the crosslinking agent-containing liquid was changed as follows in <Second Step> of Example 2.

<Example 3>
(Preparation of crosslinking agent-containing liquid 2)
100 parts borax 10% aqueous solution (60 ° C.), 10 parts cationized cellulose 1% aqueous solution (degree of polymerization: 1500, trade name: Poise C-150L, manufactured by Kao Corporation), 0 parts of acetylene glycol surfactant A 2% 1% aqueous solution (trade name: Orphin E1004, manufactured by Nissin Chemical Industry Co., Ltd.) was mixed and stirred to prepare a crosslinking agent-containing liquid having a concentration of 2.2% and a viscosity of 10 mPas. The coating amount at this time was 0.9 g / m ² in terms of solid content.

<Example 4>
(Preparation of crosslinking agent-containing liquid 3)
100 parts of borax 10% aqueous solution (60 ° C.), 10 parts of 2% aqueous solution of hydroxycellulose (trade name: Sanheck H, manufactured by Sanki Co., Ltd.), 0.1% aqueous solution of acetylene glycol surfactant (trade name) : Orphine E1004, manufactured by Nissin Chemical Industry Co., Ltd.) was mixed and stirred to prepare a crosslinking agent-containing liquid having a concentration of 3.2% and a viscosity of 2.4 mPas. The coating amount at this time was 1.3 g / m ² in terms of solid content.

<Example 5>
(Preparation of crosslinker-containing liquid 4)
100 parts of borax 10% aqueous solution (60 ° C.), 10 parts of 2% aqueous solution of hydroxypropylmethylcellulose (trade name: Metrolose 60SH-15, manufactured by Shin-Etsu Chemical Co., Ltd.), 0.1% aqueous solution of acetylene glycol surfactant 2 parts (trade name: Olfin E1004, manufactured by Nissin Chemical Industry Co., Ltd.) were mixed and dissolved to prepare a crosslinking agent-containing liquid having a concentration of 3.2% and a viscosity of 3 mPas. The coating amount at this time was 1.3 g / m ² in terms of solid content.
A 2% aqueous solution of hydroxypropylmethylcellulose was prepared as follows. That is, 2 parts of hydroxypropylmethylcellulose was added to 98 parts of cold water while stirring, and after dispersion, this was heated to a liquid temperature of 95 ° C. and held for 1 hour, and then cooled to a liquid temperature of 10 ° C. A 2% aqueous hydroxypropyl methylcellulose solution was obtained.

<Example 6>
(Preparation of crosslinking agent-containing liquid 5)
100 parts (60 ° C.) of a 10% aqueous borax solution, 5 parts by weight of a 2% aqueous solution of carboxymethyl cellulose (degree of polymerization: 1000, trade name: Cellogen WSA, Daiichi Kogyo Seiyaku), 0. 0% of an acetylene glycol surfactant. 2 parts of a 1% aqueous solution (trade name: Orphin E1004, manufactured by Nissin Chemical Industry Co., Ltd.) was mixed and dissolved to prepare a crosslinking agent-containing liquid having a concentration of 3.3% and a viscosity of 3 mPas. The coating amount at this time was 1.3 g / m ² in terms of solid content.

<Example 7 >
(Preparation of crosslinking agent-containing liquid 7)
100 parts of boric acid 10% aqueous solution (60 ° C.), 1 part aqueous solution of cationized cellulose (degree of polymerization: 1500, trade name: Poise C-150L, manufactured by Kao Corporation), 0 parts of acetylene glycol surfactant A 2% 1% aqueous solution (trade name: Orphin E1004, manufactured by Nissin Chemical Industry Co., Ltd.) was mixed and stirred to prepare a crosslinking agent-containing solution having a concentration of 3.2% and a viscosity of 2 mPas. The coating amount at this time was 1.3 g / m ² in terms of solid content.

<Example 8 >
(Preparation of crosslinking agent-containing liquid 8)
100 parts of borax 10% aqueous solution (60 ° C.), 10 parts of 1% aqueous solution of cationized cellulose (degree of polymerization: 600, trade name: Poise C-60H, manufactured by Kao Corporation), 0 of acetylene glycol surfactant A 2% 1% aqueous solution (trade name: Orphin E1004, manufactured by Nissin Chemical Industry Co., Ltd.) was mixed and stirred to prepare a crosslinker-containing solution having a concentration of 7% and a viscosity of 15 mPas. The coating amount at this time was 2.8 g / m ² in terms of solid content.

<Comparative Examples 1-4>
An ink jet recording sheet was completed in the same manner as in Example 2 except that the crosslinking agent-containing liquid was changed as follows in <Second Step> of Example 2.

<Comparative Example 1>
(Preparation of crosslinker-containing liquid 9: no crosslinker included)
Water was added to 10 parts of a 1% aqueous solution of cationized cellulose (degree of polymerization: 1500, trade name: Poise C-150L, manufactured by Kao Corporation) and stirred to adjust the concentration to 0.5%.
The treatment liquid was coated on a support with a Mayer bar so that the coating amount was 40 g / m ² and dried at a dryer temperature of 100 ° C. for 1 minute. The coating amount at this time was 0.2 g / m ² in terms of solid content.

<Comparative example 2>
(Preparation of crosslinker-containing liquid 10)
After mixing and stirring 100 parts of a 5% aqueous solution of borax and 2 parts of a 0.1% aqueous solution of acetylene glycol surfactant (trade name: Olphine E1004, manufactured by Nissin Chemical Industry Co., Ltd.), water was added to obtain a concentration of 2 Adjusted to 2%. The viscosity of the crosslinking agent-containing liquid was 1 mPas. The solution was coated on a support with a Mayer bar so that the coating amount was 40 g / m ² and dried at a dryer temperature of 100 ° C. for 1 minute. The coating amount at this time was 0.9 g / m ² in terms of solid content.

<Comparative Example 3>
(Preparation of crosslinking agent-containing liquid 11)
100 parts of 5% borax aqueous solution, 20 parts of 1% aqueous solution of cationized cellulose (degree of polymerization: 1500, trade name: Poise C-150L, manufactured by Kao Corporation), 0.1% aqueous solution of acetylene glycol surfactant (Product name: Olfin E1004, manufactured by Nissin Chemical Industry Co., Ltd.) 1.5 parts was mixed and stirred to prepare a crosslinking agent-containing liquid having a concentration of 2.2% and a viscosity of 35 mPas. The coating amount at this time was 0.9 g / m ² in terms of solid content.

<Comparative example 4>
(Preparation of crosslinking agent treatment liquid 12)
10 parts of 1% aqueous solution of cationized cellulose (degree of polymerization: 1500, trade name: Poise C-150L, manufactured by Kao Corporation) and 0.1% aqueous solution of acetylene glycol surfactant (trade name: Olphine E1004, Sun 0.5 parts) (manufactured by Shin Chemical Industry Co., Ltd.) was mixed and stirred to prepare a crosslinking agent-containing liquid having a concentration of 0.7% and a viscosity of 10 mPas. The coating amount at this time was 0.3 g / m ² in terms of solid content.

<Comparative Example 5>
In <Third Step> of Example 2, an ink receiving layer forming coating solution 2 using an SBR emulsion was prepared and applied instead of the polyvinyl alcohol of (ink receiving layer forming coating solution 1). did. Otherwise, an ink jet recording sheet was obtained in the same manner as in Example 2.
(Formation of ink receiving layer forming coating solution 2)
10 parts of a styrene-butadiene copolymer latex (trade name: OX1060, manufactured by Nippon Zeon Co., Ltd.) was mixed with 100 parts of silica sol A to prepare an ink-receiving layer-forming coating liquid 2.
In addition, it coats on the said support body so that the coating amount may become 22g / m < ² > in conversion of solid content with a die coater, and it dries at a dryer temperature of 100 degreeC for 2 minutes, forms an ink receiving layer, and glossiness is expressed. The formation of the layer is the same as in Example 5.

<Comparative Example 6>
(Preparation of crosslinker-containing liquid 6)
100 parts of borax 10% aqueous solution (60 ° C.), 10 parts of 5% aqueous solution of gelatin (trade name: P-100, Miyagi Chemical Industry), 0.1% aqueous solution of acetylene glycol surfactant (trade name: 2 parts of Olfine E1004 (manufactured by Nissin Chemical Industry Co., Ltd.) were mixed and dissolved to prepare a cross-linking agent-containing solution having a concentration of 3.3% and a viscosity of 2.4 mPas. The coating amount at this time was 1.3 g / m ² in terms of solid content .
A 5% aqueous solution of gelatin was prepared as follows. That is, 5 parts of gelatin was added and dispersed in 95 parts of cold water with stirring, and then heated to 95 ° C. and held for 1 hour. It was then cooled to room temperature to obtain a 5% gelatin solution.
<Example 9 >
An ink jet recording sheet was completed in the same manner as in Example 1 except that the crosslinking agent-containing liquid was changed to the following in <Second Step> of Example 1.
(Preparation of treatment liquid 13)
Mixing and stirring 100 parts of a zirconium-based crosslinking agent (trade name: AZ coat, manufactured by San Nopco) and 3 parts of a 1% aqueous solution of cationized cellulose (degree of polymerization: 1500, trade name: Poise C-150L, manufactured by Kao Corporation) Then, water was added thereto to prepare a treatment liquid containing a material having an action of gelling or thickening at a concentration of 5% and a viscosity of 15 mPas.
The treatment liquid was coated on a support so as to be 40 g / m ² with a Mayer bar, and dried at a dryer temperature of 100 ° C. for 1 minute. The coating amount at this time was 2.0 g / m ² in terms of solid content.

<Evaluation method>
In the obtained Examples and Comparative Examples, the coating suitability of the liquid containing a crosslinking agent (uniformity of repelling and surface quality), the suitability of application liquid for forming an ink receiving layer (die coating suitability), and an inkjet recording sheet The ink receiving layer was cracked, 75 ° surface gloss, ink absorptivity, printing blur, and printing density were evaluated according to the following evaluation criteria. Moreover, the viscosity of the crosslinking agent-containing liquid is also shown in Table 1.

(Coating suitability of crosslinker-containing liquid: repellent)
The degree of repellency of the crosslinking agent-containing coating solution coated on the support was visually evaluated.
A: No repelling is observed, and there is no problem with the coated surface.
○: Slight repellency is observed when the number of cistern is less than 0.5 / m ² , but there is no practical problem.
(Triangle | delta): The number of repelling is 0.5 piece / m < ² > or more and less than 1.0 piece / m < ² >, and a problem may generate | occur | produce practically.
X: The number of repels is 1.0 / m ² or more, which is problematic in practical use.

(Coating suitability of crosslinker-containing liquid: uniformity of coating surface quality)
The surface quality of the coating solution containing a crosslinking agent coated on the support was visually evaluated.
A: A glossy and uniform coated surface is obtained, and there is no problem.
○: A uniform coated surface is obtained and there is no problem.
Δ: The coating surface is slightly rippled, and the coating is slightly uneven.
X: The coating surface is rippled and coating is not uniform or does not have a desired coating amount.

(Die coating suitability)
The applicability of the die coating when the ink-receiving layer forming coating solution was applied was visually evaluated in the vicinity of the paint discharge portion of the die coating head.
A: In the vicinity of the surface of the die discharge part, the coating liquid for forming the ink receiving layer is not gelled by a material having an action of gelling or thickening, and a uniform coating is obtained and the operation is good.
◯: The ink receiving layer forming coating liquid in the vicinity of both ends of the surface of the die discharge part is slightly gelled, but there is no practical problem. (Because the die coating head discharge part and the support were close to each other due to the curling of the support, it gelled.)
Δ: The ink receiving layer forming coating solution partially gelated not only near both ends of the surface of the die discharge part, but the appearance after drying was hardly affected and there was no practical problem.
X: In the vicinity of the surface of the die discharge part, the ink receiving layer forming coating solution is gelled by a material having an action of gelling or thickening, and a uniform coated surface cannot be obtained and operation is impossible.

(Crack of ink receiving layer)
The degree of cracking of the ink receiving layer was visually evaluated.
(Double-circle): A crack is not seen at all.
○: Some cracks occur, but there is no practical problem.
Δ: There are slightly more cracks than ○, but there is no practical problem.
X: Cracks occur and there are practical problems.

(75 degree surface gloss)
The 75 degree glossiness of the ink receiving layer surface of the inkjet recording sheet was measured by the method described in JIS-P8142.

(Ink absorption)
Green solid printing was performed using an inkjet printer PIXUS iP4200 manufactured by Canon Inc., and the degree of ink absorption in the solid printing portion was visually evaluated. As the ink cartridge, BCI-7Bk, BCI-7C, BCI-7M, BCI-7Y and BCI-3eBk manufactured by Canon Inc. were used.
A: No unevenness is observed in the solid print part, and it is in a good state.
◯: A level at which a slight unevenness is observed in the solid print portion but hardly causes a problem.
Δ: A level in which some unevenness is seen in the solid print portion and may cause a problem when printing including a lot of solid printing.
X: Level in which unevenness is observed in the solid print portion and causes a problem.

(Printing blur)
Inkjet printer PIXUS iP4200 manufactured by Canon Inc.) performs solid printing with black, cyan, magenta, yellow, red, green, and blue adjacent to each other, and visually evaluates the degree of blurring of the color of each boundary portion. did. As the ink cartridge, BCI-7Bk, BCI-7C, BCI-7M, BCI-7Y and BCI-3eBk manufactured by Canon Inc. were used.
(Double-circle): A blurring is not seen in a boundary part but it is a favorable state.
○: Slight blurring is seen at the boundary, but it is not a problem.
Δ: A level at which blurring is slightly observed at the boundary and may cause a problem when a delicate image is printed.
X: A level in which blurring is observed at the boundary and becomes a problem.

(Print density)
Black solid printing was performed with an ink jet printer PIXUS iP7500 (manufactured by Canon Inc.), and the black solid printing portion was measured using a Gretag Macbeth reflection densitometer (made by Gretag Macbeth, RD-19I). The numbers shown in the table are average values of five measurements. The ink cartridges used were Canon BCI-7Bk, BCI-7C, BCI-7M, BCI-7Y, BCI-7PC, BCI-7PM, BCI-7R, and BCI-7G.

Claims (6)

In a method for producing an inkjet recording sheet having at least an ink absorbing layer and an ink receiving layer on a support, a first step of providing an ink absorbing layer on at least one surface of the support, the ink absorbing layer on the ink absorbing layer A second step of coating a material having an action of gelling or thickening upon contact with the ink-receiving layer-forming coating liquid, and a crosslinking agent-containing liquid containing a cellulose derivative as a viscosity modifier, at least an average A method for producing an ink jet recording sheet, comprising a third step of applying an ink receiving layer containing fine particles having a particle diameter of 5 nm to 700 nm. Cellulose derivatives as a viscosity modifier, cationized cellulose, carboxymethyl cellulose, hydroxyethyl cellulose and inkjet recording method of manufacturing a sheet according to claim 1 hydroxypropylmethyl is methyl cells one or more selected from low scan or Ranaru group. Method for producing a Lee inkjet recording sheet of the viscosity of the crosslinking agent-containing solution according to claim 1 or 2 wherein the 2mPas~20mPas (B type viscometer). Any cross-linking agent contained in the crosslinking agent-containing solution is a boric acid and / or borax, and the claims 1-3, characterized in that it contains polyvinyl alcohol in the ink-receiving layer forming coating solution The manufacturing method of the sheet | seat for inkjet recording of description. During the crosslinking agent-containing liquid, an ink jet method for producing a recording sheet according to any one of claims 1-4, characterized in that it comprises a surfactant. After coating the ink receiving layer, any one of claims 1-5, characterized in that it comprises a fourth step of applying at least a glossy layer containing an average particle diameter of 5nm or more 100nm or less colloidal particles The manufacturing method of the sheet | seat for inkjet recording of description.