JP2010179647A - Method for manufacturing ink-jet recording sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an ink-jet recording sheet which is excellent in gloss, image quality and ink absorbency, is suppressive in crack and break, and also is excellent in water resistance. <P>SOLUTION: A coating solution for forming an ink receiving layer containing particulates and poly(vinyl alcohol) having polymerization degree of ≥2,000 is applied onto a support and then is dried to obtain the ink-jet recording sheet. In this method for manufacturing the ink-jet recording sheet, an aqueous solution of a cross-linking agent cross-linkable to the poly(vinyl alcohol) is applied onto the support before or simultaneously with application of the coating solution for forming the ink receiving layer. Further the cross-linking agent contains at least one sort among zirconyl nitrate, zirconyl chloride and hydroxy zirconyl chloride. <P>COPYRIGHT: (C)2010,JPO&INPIT

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.

  As a recording sheet suitable for the ink jet recording method, an ink jet recording sheet having an ink receiving layer is widely used. The inkjet recording sheet is required to have advanced characteristics due to the rapid spread of printers, high definition and high speed, and the advent of digital cameras. For example, there is a strong demand for ink jet recording sheets having ink absorptivity and image quality and gloss comparable to silver salt photography.

  In order to achieve this, it is necessary to obtain high ink absorption speed and gloss by using fine particles in the ink receiving layer, and to reproduce the roundness of dots by controlling cracks in the coating film of the ink receiving layer. is there.

Patent Documents 1 and 2 propose a method for manufacturing an ink jet recording sheet that satisfies the above requirements. There has been proposed an ink jet recording sheet comprising an inorganic pigment fine particle having an average primary particle diameter of 20 nm or less in an ink receiving layer and a water-soluble resin containing polyvinyl alcohol. This is due to the use of a cross-linking reaction between borax or boric acid and polyvinyl alcohol. Can be granted.
In Patent Document 2, boric acid or a boron compound is coated on the support between the support and the ink recording layer in an amount of 0.1 g / m ² or more per one surface of the support. The polyvinyl alcohol is cross-linked by boric acid or boron compound of the undercoat, and the coating is gelled before the recording layer becomes a reduced rate drying portion, thereby suppressing cracking of the coating film.
In Patent Document 3, first, an undercoat-forming coating liquid containing fine particles and a water-soluble resin is applied onto a support to form an undercoat layer, and 1.4 mass of borax is formed on the undercoat layer. A coating solution containing a crosslinking agent containing at a concentration of not more than% is applied. Then, before the coated crosslinking agent-containing coating liquid is dried, an ink receiving layer forming coating liquid containing fine particles and a water-soluble resin is coated thereon to form an ink receiving layer. According to this method, the coating strength can be increased by crosslinking the water-soluble resin of the undercoat layer and the ink absorbing layer with borax in the coating liquid containing the crosslinking agent. As a result, the undercoat layer and the ink receiving layer can be thickened and the amount of ink retained can be increased, so that the image quality can be improved. In addition, the ink absorbency can be enhanced by the undercoat layer containing fine particles.

In recent years, with the spread of general home users, in order to facilitate installation in a small room, it has been required to reduce the area required for printer installation. As one of the solutions, a recording sheet is used as a printer. An increasing number of inkjet printers employ a paper feeding method in which a printing surface is set downward on a lower paper feed tray and a recording medium is rotated inside the printer so that the printing surface faces upward. This paper feeding method is sometimes referred to as C-type paper feeding or the like, in which the state of rotation of the recording medium inside the printer is compared to the letter “C” in the alphabet. In contrast to paper, this is called J-type paper feed.)
In C-type paper feeding, when the recording sheet is rotated in a narrow paper feeding path inside the printer, a large tension is applied to the surface of the ink receiving layer, and the ink receiving layer is cracked (hereinafter also referred to as folding). ) Is likely to occur.

  Inkjet recording sheets produced by the production methods described in Patent Documents 1, 2, and 3 are excellent in gloss, image quality, and ink absorbency, but the ink-receiving layer is easily broken, and the ink has sufficient water resistance. It wasn't.

On the other hand, Patent Documents 4 and 5 disclose that a cross-linking agent is added to an ink receiving layer containing inorganic fine particles having an average secondary particle diameter of 500 nm or less and acetoacetyl-modified polyvinyl alcohol in order to prevent the ink receiving layer from being cracked or broken. There are proposals for containing or undercoating a dihydrazide compound or a polyvalent metal salt.
Patent Document 6 proposes an inkjet recording medium containing an acetoacetate group-containing polyvinyl alcohol resin, a cationic group-containing polyvinyl alcohol resin, a zirconium compound, and inorganic fine particles, but has a sufficient crack-inhibiting effect. It was not obtained.

Japanese Patent Laid-Open No. 11-115308 JP 2001-246832 A Japanese Patent Laid-Open No. 2004-74576 JP 2005-335119 A JP-A-2005-335120 JP 2006-263926 A

  The present invention provides a method for producing an ink jet recording sheet that is excellent in all of gloss, image quality, and ink absorbency, and further, is suppressed from cracking and cracking of the ink receiving layer, and further excellent in water resistance. With the goal.

As a result of studies conducted by the present inventors to solve the above-mentioned problems, the crosslinking agent used for the purpose of suppressing cracking of the ink receiving layer and the polyvinyl alcohol contained in the coating solution for forming the ink receiving layer are crosslinked. As a result of finding that the ink-jet recording sheet is easily cracked by being hardened, and as a result of intensive research, after forming a specific cross-linking agent in advance, forming an ink receiving layer having a specific polyvinyl alcohol It has been found that by applying the coating liquid, cracking and cracking can be suppressed and water resistance can be further improved.
And based on those knowledge, the following manufacturing method of the sheet | seat for inkjet recording was invented.
[1] In the method for producing an ink jet recording sheet, on the support, a coating liquid for forming an ink receiving layer containing fine particles and polyvinyl alcohol having a polymerization degree of 2000 or more is applied and dried to form an ink receiving layer. An aqueous solution of a crosslinking agent capable of crosslinking with polyvinyl alcohol is applied to a support prior to or simultaneously with the application of the ink-receiving layer-forming coating solution, and the crosslinking agent is zirconyl nitrate, A method for producing an ink jet recording sheet, comprising at least one of zirconyl chloride and zirconyl hydroxychloride.
[2] The method for producing an inkjet recording sheet according to [1], wherein the polyvinyl alcohol has a saponification degree of 97 mol% or more.
[3] The method for producing an inkjet recording sheet according to [1] or [2], wherein the crosslinking agent is zirconyl nitrate or zirconyl chloride.
[4] The method for producing an inkjet recording sheet according to any one of [1] to [3], which is obtained by coating an aqueous solution of the crosslinking agent before forming the ink receiving layer.

  According to the method for producing an ink jet recording sheet of the present invention, the gloss, image quality, and ink absorbability are all excellent, and the ink receiving layer is prevented from being cracked and cracked, and further has excellent water resistance. Recording sheets can be manufactured.

"Support"
The support is not limited in its air permeability, and any one from a gas-permeable support to a non-air-permeable support can be used, but a gas-permeable support is preferred. This is because when an air-permeable support is used, an aqueous solution of a crosslinking agent and a coating solution for forming an undercoat layer can be applied uniformly. Further, when the recording sheet is cast-finished, an air permeable support is preferably used.

[Air-permeable support]
The air permeable support is not particularly limited as long as it has air permeability, and an acid paper used for general coated paper or the like, or a gas permeable support such as neutral paper is appropriately used. . As wood pulp constituting the air-permeable support, chemical pulp such as kraft pulp (KP), sulfite pulp (SP), soda pulp (AP), semi-chemical pulp (SCP), chemi-ground wood pulp (CGP), etc. Semi-chemical pulp, groundwood pulp (GP), thermomechanical pulp (TMP, BCTMP), refiner Grandwood pulp (RGP) Deinked pulp made from Further, it is preferable to use a pulp bleached by combining various bleaching methods such as chlorine, chlorine dioxide, oxygen, ozone, hydrogen peroxide, hypochlorous acid, etc., in order to obtain high whiteness. Among these, chlorine-free pulp that has been subjected to ECF bleaching or TCF bleaching is preferable because it hardly causes yellowing even when recording paper is stored for a long period of time. These pulps may be used alone or in combination of two or more.

  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 recording on the recording paper, paper blurring or bleeding of the recorded image caused by moisture in the ink may produce better results if the beating is not advanced. Many. Accordingly, the freeness is preferably about 300 to 500 ml.

A sizing agent, a fixing agent, a paper strength enhancing agent, a cationizing agent, a yield improving agent, a dye, a fluorescent whitening agent, and the like can be added to the gas-permeable support as an auxiliary agent during papermaking. Furthermore, in the size press process of the paper machine, starch, polyvinyl alcohol, cationic resin and the like can be applied and impregnated to adjust the surface strength, sizing degree, and the like. The Steecht sizing degree (as 100 g / m ² paper) is preferably about 1 to 200 seconds. If the sizing degree is low, there may be operational problems such as wrinkling during coating, and if it is high, the ink absorbability may be reduced, and curling and cockling after printing may be remarkable. A more preferred range of sizing is 4 to 120 seconds. Although the basic weight of a gas-permeable support body is not specifically limited, About 20-400 g / m < ² >, Preferably it is 100-350 g / m < ² >. If the basis weight is too small, curling or cockling tends to be remarkable or opacity tends to be difficult to obtain when ink jet recording is performed. Moreover, when too large, it exists in the tendency for glossiness to be inferior.

  When performing the cast finish, the air permeability of the air permeable support is preferably about 10 to 1000 seconds / 100 cc, more preferably about 10 to 500 seconds / 100 cc, particularly preferably 10 to 10 seconds. 200 seconds / 100 cc. Incidentally, when the air permeability increases, the gloss tends to be inferior. This is because the outermost layer in a wet state is dried using a heated mirror drum, so that the water in the coating solution is evaporated through the air-permeable support, but if the air permeability is high, drying is not possible. It is considered that the glossiness is inferior because it is sufficient or heated more than necessary. In addition, if the air permeability is further increased, the operability at the time of cast finishing becomes poor. On the other hand, in the case of an air-permeable support that is less than 10 seconds / 100 cc, glossiness also tends to be lowered. This is because when the ink jet recording layer is formed, most of the adhesive in the coating liquid penetrates into the air-permeable support, and the amount of adhesive in the ink jet recording layer is reduced, resulting in glossiness. Is likely to be inferior.

  The paper machine is not particularly limited, and a known long web paper machine, cylindrical paper machine, Yankee paper machine, twin wire former, inclined wire forner, etc., and as a dryer, a Yankee dryer, other cylindrical dryers, etc. Various known paper machines can be used. Known processing such as calendar processing is also possible.

[Non-permeable support]
Non-permeable supports (including low-permeable supports) include films such as cellophane, polyethylene, polypropylene, soft polyvinyl chloride, hard polyvinyl chloride, polyester, art paper, coated paper, cast coated paper, Examples include foil paper, kraft paper, polyolefin resin-coated paper, impregnated paper, vapor-deposited paper, paper such as water-soluble paper, and sheets such as metal foil and synthetic paper. For these, art paper, coated paper, baryta paper, photographic paper base paper, synthetic paper, and polyolefin resin-coated paper are preferable. Among them, synthetic paper and polyethylene resin-coated paper are preferable, and in particular, a support made of polyethylene resin-coated paper kneaded with titanium oxide, so-called RC paper, is particularly preferably used because the finished appearance is equivalent to that of photographic printing paper. It is done. A support coated with gelatin is also preferred.

  In the polyethylene resin-coated paper, the thickness of the polyethylene layer is preferably 3 to 50 μm, and more preferably 5 to 30 μm. When the thickness of the polyethylene layer is less than 3 μm, defects such as polyethylene holes are likely to increase during resin coating, and it is often difficult to control the thickness, making it difficult to obtain smoothness. On the other hand, if it exceeds 50 μm, the resulting effect is small and uneconomical for the increase in cost.

"Undercoat"
The support may have an undercoat layer. The undercoat layer is an absorption layer for quickly separating the ink coloring component and the solvent component that has landed on the ink receiving layer, an absorption layer for absorbing an ink solvent that cannot be absorbed by the ink receiving layer, and an ink solvent as a support. Examples thereof include a shielding layer for preventing permeation, a smoothing layer for smoothing the surface of the support for enhancing the glossiness of the recording sheet, and a colored layer for adjusting the color tone of the recording sheet. In the present invention, the term “support” includes an undercoat layer unless otherwise specified.

"Ink receiving layer"
In the present invention, when the ink receiving layer is formed on the support, an aqueous solution of a crosslinking agent capable of crosslinking with polyvinyl alcohol is applied prior to or simultaneously with the application of the ink receiving layer forming coating solution. It is something to apply to.

[Crosslinking agent]
Examples of the crosslinking agent contained in the aqueous solution of the crosslinking agent include substances that crosslink with polyvinyl alcohol, such as boron compounds, epoxy compounds, glycidyl compounds, aluminum compounds, chromium compounds, and zirconium compounds. At least one selected from zirconyl, zirconyl chloride, and hydroxy zirconyl chloride is used. When these cross-linking agents are combined with specific polyvinyl alcohol, the ink receiving layer cracking may be carried out without impairing ink absorbability, either because the viscosity of the ink receiving layer-forming coating liquid or the progress of gelation is moderately fast. In addition, the cracking can be improved, and the ink water resistance when printing with an ink jet printer is improved. The content of the crosslinking agent is preferably in 0.1-5 g / ^{m 2} in terms of ZrO _2, and more preferably adjusted to be 0.5 to 3 g / ^{m 2.}

  In addition, when using zirconyl nitrate, since it will be easy to yellow by light if there exists calcium, such as a calcium carbonate, in a support body, it is preferable to reduce a compounding quantity. Specifically, it is preferable to use calcium carbonate as a filler for the paper support, use kaolin, talc, or the like, and use calcium carbonate or satin white for the undercoat layer, and use kaolin, silica, or the like.

  A surfactant may be contained in the aqueous crosslinking agent solution. As the surfactant, any of an anionic surfactant, a cationic surfactant, and a nonionic surfactant may be used. Among the above surfactants, nonionic surfactants are preferred because of their high affinity with ink jet printer inks. Furthermore, among nonionic surfactants, acetylene glycol and alkyl ether surfactants are preferred. preferable.

  Further, the aqueous crosslinking agent solution may contain various auxiliary agents such as various dispersants, thickeners, antifoaming agents, colorants, antistatic agents, preservatives, fluorescent dyes, and colored pigments.

[Coating method]
Examples of the coating method of the aqueous crosslinking agent solution on the support 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. It is done.

[Fine particles]
Examples of the fine particles contained in the ink-receiving layer-forming coating liquid include amorphous silica (including synthetic amorphous silica produced by a wet method and a dry method, and cation-modified silica such as alumina), and amorphous. Amorphous silica-cationic compound aggregate particles obtained by mixing and aggregating silica and a cationic compound, kaolin, clay, calcined clay, zinc oxide, tin oxide, titanium dioxide, magnesium sulfate, aluminum hydroxide, alumino Silicate, alumina, alumina hydrate, colloidal silica, calcium carbonate, satin white, aluminum silicate, smectite, zeolite, magnesium silicate, magnesium carbonate, magnesium oxide, diatomaceous earth, styrene-based plastic pigment, urea resin-based plastic pigment, benzogua Such as Min-based plastic pigments and the like.
Among these, since the gloss and ink absorbability of the resulting inkjet recording sheet can be easily balanced, at least one selected from the group consisting of amorphous silica, aluminosilicate, alumina, and alumina hydrate is included. It is preferable. Also in the fine particles contained in the ink receiving layer forming coating solution, the average secondary particle diameter of the fine particles is preferably 0.7 μm or less, particularly from the viewpoint of gloss.
The average secondary particle diameter here is the number average secondary particle diameter obtained by adjusting the concentration of the aqueous pigment dispersion to 1% and obtaining the dynamic light scattering method at 25 ° C. In the present invention, a thick particle size analyzer FPAR-1000 (manufactured by Otsuka Electronics Co., Ltd.) was used as the measuring apparatus.

[Polyvinyl alcohol]
Examples of the polyvinyl alcohol contained in the ink receiving layer-forming coating liquid include unmodified polyvinyl alcohol, cation-modified polyvinyl alcohol, silyl-modified polyvinyl alcohol, and acetoacetyl-modified polyvinyl alcohol. Among these, those having a degree of polymerization of 2000 or more are used from the viewpoint of ink absorbency and suppression of cracks. If the degree of polymerization is less than 2000, it is difficult to control cracks in the resulting ink receiving layer. When the degree of polymerization is 3000 or more, the ink-receiving layer does not easily crack, and those exceeding 5000 are difficult to obtain practically. Therefore, it is preferable to use polyvinyl alcohol having a degree of polymerization of 3000 to 5000. . Moreover, since sufficient reaction with a crosslinking agent is obtained and crack control becomes easy, the saponification degree is preferably 97% or more.

  The polyvinyl alcohol is used in an amount of preferably 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. As mass ratio of polyvinyl alcohol and a crosslinking agent, 20: 1 to 1:20 are preferable and 10: 1 to 1:10 are more preferable. By setting the mass ratio within this range, an ink jet recording sheet excellent in crack suppression, ink water resistance and ink absorbability can be obtained.

[mordant]
In the present invention, a mordant is preferably contained in the ink-receiving layer-forming coating liquid in order to improve ink water resistance and fixability. Examples of mordants include organic mordants and inorganic mordants. The organic mordant and the inorganic mordant may be used alone, respectively, or the organic mordant and the inorganic mordant may be used in combination.

  Examples of the organic mordant include a polymer mordant having a primary to tertiary amino group or a quaternary ammonium base as a cationic group. These mordants are preferably compounds having an average molecular weight of 500 to 500,000 from the viewpoint of improving ink absorbability of the colorant receiving layer. Inorganic mordants include magnesium, aluminum, calcium, scandium, titanium, vanadium, manganese, iron, nickel, copper, zinc, gallium, germanium, strontium, yttrium, zirconium, molybdenum, indium, barium, lanthanum, cerium, praseodymium, neodymium And salts or complexes of metals selected from samarium, europium, gadolinium, dysproprosium, erbium, ytterbium, hafnium, tungsten, bismuth. Among these, aluminum-containing compounds, titanium-containing compounds, zirconium-containing compounds, and group IIIB series metal compounds (salts or complexes) are preferable.

  The mordant content is preferably 1 to 20% by mass and more preferably 2 to 15% by mass with respect to the total solid mass of the ink receiving layer.

[Other ingredients]
The ink-receiving layer-forming coating liquid may contain a water-dispersible resin as long as the object of the present invention is achieved. Examples of the water-dispersed resin include vinyl copolymers such as styrene-butadiene copolymer, conjugated diene polymer latex of methyl methacrylate-butadiene copolymer, acrylic polymer latex, and styrene-vinyl acetate copolymer. Examples include latex.

  Further, the ink receiving layer forming coating solution may contain a surfactant. As the surfactant, any of an anionic surfactant, a cationic surfactant, and a nonionic surfactant may be used. Among the above surfactants, nonionic surfactants are preferred because of their high affinity with ink jet printer inks. Furthermore, among nonionic surfactants, acetylene glycol and alkyl ether surfactants are preferred. preferable.

  Further, the ink receiving layer forming coating liquid may contain various auxiliary agents such as various dispersants, thickeners, antifoaming agents, colorants, antistatic agents, preservatives, fluorescent dyes, and colored pigments. Good.

[Coating method, drying method]
As the coating method and drying method of the ink receiving layer forming coating solution, those similar to the coating method and drying method of the aqueous crosslinking agent solution can be applied. When the support is a gas-permeable support, the coating amount of the ink-receiving layer-forming coating liquid is preferably such that the coating amount of the ink-receiving layer is 3 to 25 g / m ^2. In the case of a tempered support, the amount is preferably 10 to 40 g / m ² . If the coating amount is not less than the lower limit, sufficient ink absorbability and image quality can be ensured, and if it is not more than the upper limit, cracking of the ink receiving layer can be suppressed. If the coating amount is in the above range, an image quality comparable to a silver salt photograph can be obtained. In the case of using an air-permeable support, the ink-receiving layer-forming coating solution can be dried by a casting method, and after drying the ink-receiving layer-forming coating solution, It can also be finished by casting.

[Glossy layer]
In the present invention, a gloss layer containing fine particles may be formed on the ink receiving layer in order to increase gloss. Although it does not specifically limit as microparticles | fine-particles in a glossy layer, Colloidal silica, a gaseous-phase method silica, and an alumina oxide are preferable since the outstanding glossiness is obtained.
Since the glossy layer is mainly intended for glossiness, the ink 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 primary particle diameter of 3 to 100 nm and an average (secondary) particle diameter of 700 nm or less. The average (secondary) particle size referred to here is the number average secondary particle size obtained by adjusting the concentration of the aqueous pigment dispersion to 1% and obtaining the dynamic light scattering method at 25 ° C. .

    The gloss layer may appropriately contain the water-dispersible resin, water-soluble resin such as gelatin, celluloses, starch, and polyvinyl alcohol as long as the ink absorbability is not impaired. Moreover, the said mordant can also be contained as needed. Further, various auxiliary agents such as various dispersants, thickeners, antifoaming agents, colorants, antistatic agents, preservatives, fluorescent dyes, and colored pigments may be contained.

As a method for forming the gloss layer, for example, a gloss layer forming coating liquid containing fine particles and a solvent is applied on the ink receiving layer, or an ink receiving layer forming coating liquid and a gloss layer forming coating liquid are applied. Simultaneous multilayer coating is recommended.
Further, when a gas-permeable support is used, it can be finished by a so-called casting method obtained by pressing and drying a heated mirror drum while the gloss layer forming coating liquid is in a wet state.
In this case, in order to make it easy to peel off from the mirror drum, various release agents may be appropriately added to the gloss layer forming coating solution. The addition amount of the release agent is preferably about 0.5 to 10 parts by mass with respect to 100 parts by mass of the fine particles.
When the support is a non-permeable support or a low-permeable support, the gloss layer forming coating solution is pressed against the mirror drum immediately after coating or while coating (for example, see WO 03/039881) Nipping as shown) and drying in a subsequent drying apparatus.

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 0.2-5 g / ^{m 2,} more preferably 0.5 to 2 g / ^{m 2} . When the coating amount is too small, the coating film becomes thin and interference color due to light is likely to be generated. On the other hand, when the coating amount is too large, the ink absorption rate is remarkably lowered and the transparency may be lowered.

[Other coating layers]
In the present invention, a back layer can be provided for the purpose of improving the curl and transportability of the air-permeable support. Further, a polyethylene coating layer may be provided on the back surface layer in order to give the texture of the photograph.
Moreover, you may form adhesive layers, such as a well-known recording layer, an adhesive, and an adhesive agent which provide recording suitability, such as inkjet recording, thermal recording, thermal transfer recording, and magnetic recording, on the other surface of a support body. It can also be bonded to another support.

  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.

(Silica sol A)
10 parts of diallyldimethylammonium chloride (trade name: Charol DC-902P, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) is added to commercially available vapor phase silica (manufactured by Nippon Aerosil Co., Ltd., trade name: Aerosil A200, specific surface area 200 m ² / g). Were dispersed with a sand grinder and then further dispersed with a pressure homogenizer. The dispersion operation of the sand grinder and the pressure homogenizer was repeated until the average particle size became 0.08 μm to prepare an aqueous dispersion.

(Support A)
100 parts of wood pulp (LBKP: freeness = 450 ml CSF, chlorine-free pulp produced by a four-stage sequence of Ze-E-P-D), 7 parts of filler (mixed calcium carbonate and talc at 7: 3), 0.04 parts of a commercial sizing agent, 0.45 parts of aluminum sulfate, 1.00 parts of starch, using retention aids Some become more papermaking material, a wood free paper having a basis weight of 175 g / ^{m 2} by the Fourdrinier After being obtained, a super calender treatment was performed with a dryer, a size press, and a linear pressure of 100 kg / cm to obtain a paper support. In the size press process, 6.5% of carboxyl-modified polyvinyl alcohol and starch (trade name: Ace A, manufactured by Oji Cornstarch Co., Ltd.) mixed and dissolved at a ratio of 4: 1, alkyl ketene dimer (external sizing agent) A size press solution containing 0.5% (trade name: SPK-287, manufactured by Arakawa Chemical Industries, Ltd.) was used. The obtained paper support had an ash content of 5% and a thickness of 200 μm.

(Support B)
After the corona discharge treatment is applied to both surfaces of the support A, the following polyolefin resin composition 1 mixed and dispersed by a Banbury mixer is applied to the felt surface side of the support A so that the coating amount is 25 g / m ^2. Coating was performed by a melt extruder (melting temperature: 320 ° C.) having a mold die. Moreover, the following polyolefin resin composition 2 was coated on the wire side of the support A with the above melt extruder so that the coating amount was 20 g / m ² . Thereafter, the felt surface side is cooled and solidified with a mirror surface cooling roll, and the wire surface side is cooled and solidified. The smoothness (Oken type, J.TAPPI No. 5) is 6000 seconds, and the opacity (JIS P8138). A 93% resin-coated support B was obtained.

[Polyolefin resin composition 1]
Linear low density polyethylene (density 0.926 g / cm ³ , melt index 20 g / 10 min) 35 parts, low density polyethylene (density 0.919 g / cm ³ , melt index 2 g / 10 min) 50 parts, anatase type dioxide Titanium (trade name: A-220, manufactured by Ishihara Sangyo Co., Ltd.) 15 parts, zinc stearate 0.1 part, antioxidant (trade name: Irganox 1010, manufactured by Ciba Specialty Chemicals) 0.03 parts, ultramarine (trade name) : Aoguchi Ultramarine NO.2000, manufactured by Daiichi Kasei Co., Ltd.) 0.09 part, and optical brightener (trade name: UVITEX OB, manufactured by Ciba Specialty Chemicals Co., Ltd.) 0.3 part are mixed to obtain polyolefin resin composition 1 Got.

[Polyolefin resin composition 2]
65 parts of high-density polyethylene (density 0.954 g / cm ³ , melt index 20 g / 10 min) and 35 parts of low-density polyethylene (density 0.919 g / cm ³ , melt index 2 g / 10 min) are melt-mixed to obtain polyolefin. A resin composition 2 was obtained.

(Support C)
The filler of the support A (mixed with calcium carbonate and talc at 7: 3) was changed to a filler (mixed with calcium carbonate and talc at 1: 9) to obtain a paper support. The obtained paper support had an ash content of 5% and a thickness of 200 μm.

(Support D)
The substrate A filler (calcium carbonate and talc mixed at 7: 3) was changed to a filler (talc) to obtain a paper support. The obtained paper support had an ash content of 5% and a thickness of 200 μm.

(Support E)
The support A (mixed calcium carbonate and talc at a ratio of 7: 3) was changed to a filler (baked kaolin) to obtain a paper support. The obtained paper support had an ash content of 5% and a thickness of 200 μm.

(Support F)
A paper support was prepared without adding the filler of support A (calcium carbonate and talc mixed at 7: 3). The thickness of the obtained paper support was 200 μm.

Example 1
On the support A, the following crosslinking agent aqueous solution is applied using a Mayer bar so that the coating amount is 1.5 g / m ^2, and then the following ink receiving layer forming coating solution is applied with a die coater. The ink jet recording sheet 1 was obtained by coating and drying so that the work amount was 15 g / m ² .
(Crosslinking agent aqueous solution)
Zirconyl nitrate (trade name: Zircosol ZN, manufactured by Daiichi Rare Element Chemical Co., Ltd.) was converted to ZrO ₂ concentration and diluted with water to 12%, and then a commercially available surfactant (trade name: Emulgen 709, manufactured by Kao Corporation) was 0. 0.06 part was added to prepare an aqueous crosslinking agent solution.
(Formation of ink receiving layer forming coating liquid)
100 parts of silica sol A and 20 parts of polyvinyl alcohol (trade name: PVA-135, polymerization degree: 3500, saponification degree: 98%, manufactured by Kuraray Co., Ltd.) were mixed to obtain a coating liquid A for forming an ink receiving layer.

Example 2
For inkjet recording, as in Example 1, except that zirconyl chloride (trade name: Zircosol ZC-20, manufactured by Daiichi Rare Element Chemical Co., Ltd.) was used instead of zirconyl nitrate used in the aqueous crosslinking agent solution of Example 1. Sheet 2 was obtained.

Example 3
Inkjet recording was carried out in the same manner as in Example 1 except that hydroxyzirconyl chloride (trade name: Zircosol ZC-2, manufactured by Daiichi Rare Element Chemical Co., Ltd.) was used instead of zirconyl nitrate used in the aqueous crosslinking agent solution of Example 1. Sheet 3 was obtained.

Comparative Example 1
An inkjet recording sheet 4 was obtained in the same manner as in Example 1 except that a 12% borax aqueous solution was used instead of the zirconyl nitrate used in the aqueous crosslinking agent solution of Example 1.

Comparative Example 2
For inkjet recording, as in Example 1, except that zirconyl acetate (trade name: Zircosol ZA-30, manufactured by Daiichi Rare Element Chemical Co., Ltd.) was used instead of zirconyl nitrate used in the aqueous crosslinking agent solution of Example 1. Sheet 5 was obtained.

Comparative Example 3
Inkjet recording was carried out in the same manner as in Example 1 except that zirconyl ammonium carbonate (trade name: Zircosol AC-20, manufactured by Daiichi Rare Element Chemical Co., Ltd.) was used instead of zirconyl nitrate used in the aqueous crosslinking agent solution of Example 1. An attempt was made to produce a sheet. However, since the polyvinyl alcohol and zirconylammonium carbonate in the ink receiving layer forming coating solution A were gelled, the ink receiving layer forming coating solution A could not be applied onto the support. Therefore, the production of the inkjet recording sheet was stopped.

Comparative Example 4
In Example 1, polyvinyl alcohol (trade name: PVA-) instead of polyvinyl alcohol (trade name: PVA-135, polymerization degree: 3500, saponification degree: 98%, manufactured by Kuraray Co., Ltd.) as a coating liquid for forming an ink receiving layer. 117, the degree of polymerization: 1700, the degree of saponification: 98%, manufactured by Kuraray Co., Ltd., to obtain an inkjet recording sheet 6 in the same manner as in Example 1.

Example 4
In Example 1, instead of polyvinyl alcohol (trade name: PVA-135, polymerization degree: 3500, saponification degree: 98%, manufactured by Kuraray Co., Ltd.) as a coating liquid for forming an ink receiving layer, acetoacetyl-modified polyvinyl alcohol (trade name) Inkjet recording sheet 7 was obtained in the same manner as Example 1 except that: Goseifamer Z-410, polymerization degree: 2400, saponification degree: 98%, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.

Example 5
In Example 1, polyvinyl alcohol (trade name: PVA-) instead of polyvinyl alcohol (trade name: PVA-135, polymerization degree: 3500, saponification degree: 98%, manufactured by Kuraray Co., Ltd.) as a coating liquid for forming an ink receiving layer. 235, polymerization degree: 3500, saponification degree: 88%, manufactured by Kuraray Co., Ltd.), an inkjet recording sheet 8 was obtained in the same manner as in Example 1.

Example 6
In Example 1, except that the support A was changed to the support B instead of the support A, and the coating amount of the ink receiving layer forming coating liquid was changed from 15 g / m ² to 20 g / m ² In the same manner as in Example 1, an inkjet recording sheet 9 was obtained.

Example 7
(Creation of inkjet recording sheet having gloss layer)
10 parts of polyvinyl alcohol (trade name: PVA-117, polymerization degree: 1700, saponification degree: 98%, manufactured by Kuraray Co., Ltd.) to 100 parts of cationic colloidal silica (trade name: Snowtex AK, manufactured by Nissan Chemical Industries) 1 part of a cationic release agent (trade name: Pertol N856, manufactured by Modern Chemical Co., Ltd.) was mixed and diluted to 5% to prepare a silica dispersion. Next, this silica dispersion was applied onto the ink receiving layer of the inkjet recording sheet 1 obtained in Example 1. While in a wet state, the coated surface is pressed against a chrome-plated mirror surface drum with a surface temperature of 100 ° C. at a linear pressure of 2000 N / cm to form a glossy layer and then dried to obtain an inkjet recording sheet 10. It was. The gloss layer had a thickness of 1 μm.

Example 8
An ink jet recording sheet 11 was obtained in the same manner as in Example 1, except that the support C was used instead of the support A in Example 1.

Example 8
An ink jet recording sheet 12 was obtained in the same manner as in Example 1, except that the support D was used instead of the support A in Example 1.

Example 8
An ink jet recording sheet 13 was obtained in the same manner as in Example 1 except that the support A was used instead of the support A in Example 1.

Example 8
An ink jet recording sheet 14 was obtained in the same manner as in Example 1 except that the support F was used instead of the support A in Example 1.

(Evaluation methods)
The ink-receiving layer in the ink jet recording sheets of the above-described Examples and Comparative Examples was evaluated for cracking, folding, water resistance, 75 ° surface gloss, and ink absorbency as follows. The results are shown in Table 1.

(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.
○: No cracks are observed, but the surface quality is slightly inferior. There is no problem in practical use.
Δ: Cracks are partially generated, but there is no practical problem.
X: Cracks occur and there are practical problems.

(Break of ink receiving layer)
Black solid printing was performed with an inkjet printer (Photomart C8180, manufactured by Hewlett-Packard Company), and the degree of cracking of the ink receiving layer in the solid printing portion was visually evaluated. As the ink cartridge, 117 ink (black, cyan, light cyan, magenta, light magenta, yellow) manufactured by Hewlett-Packard Company was used.
(Double-circle): A crack is not seen at all.
○: Some cracking occurs, but there is no practical problem.
X: Fracture occurs and there is a problem in practical use.

(Ink water resistance)
Black solid printing and character printing are performed by an inkjet printer (Seiko Epson, PM-A840), and one drop of ion-exchange water is dropped on the black solid printing portion and the character printing portion with a dropper. The degree of ink blotting in the black solid print portion and the character print portion was visually evaluated. As the ink cartridge, ICBk32, ICC32, ICM32, ICY32, ICLC32 and ICLM32 manufactured by Seiko Epson Corporation were used.
○: Neither the black solid print portion nor the character print portion bleeds.
×: The black solid print portion and the character print portion are in a practically problematic level.

(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 iP4300, 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.

  As apparent from the results in Table 1, the ink jet recording sheet obtained according to the present invention was suppressed from cracking and cracking and excellent in water resistance.

(Evaluation methods)
The light resistance of the ink receiving layer in the ink jet recording sheets of the above-described Examples and Comparative Examples was evaluated as follows. The results are shown in Table 2.

(Light resistance)
The obtained inkjet recording sheet was processed under the following conditions using a light resistance tester (Super Xenon Weather Meter SX-75 type, manufactured by Suga Test Instruments), and the degree of yellowing of the sheet was visually evaluated.
(Processing conditions)
Irradiation amount: 80 w / m ²
Irradiation time: 72 hours Irradiation environment: 24 ° C, 60% RH
(Visual evaluation)
(Double-circle): Yellowing is not seen at all.
○: Almost no yellowing is observed. There is no problem in practical use.
Δ: Slight yellowing is observed, but there is no practical problem.
X: Yellowing is observed, but there is no problem as a recording sheet if the storage conditions are limited.
Further, the color difference (ΔE) was measured using a colorimetry tester (spectral whiteness colorimeter SC-10WN type, manufactured by Suga Test Instruments). ΔE is a value calculated by the following equation.
(formula)
_{^{ΔE = √ (L * 1 -L}} * 2) 2 + (a * 1 -a * 2) 2 + (b * 1 -b * 2) 2
L ^* ₁ , a ^* ₁ , and b ^* ₁ are L ^* , a ^* , and b ^* values before the light resistance test process, and L ^* ₂ , a ^* ₂ , and b ^* ₂ are values after the light resistance test process. L ^* , a ^* , b ^* values.

  As is clear from the results in Table 2, when zirconyl nitrate is used, if the amount of calcium carbonate in the support is reduced, an ink jet recording sheet having excellent light resistance can be obtained.

In the method for producing an ink jet recording sheet of the present invention, the cross-linking agent in the aqueous cross-linking agent solution coated on the support and the progress of thickening or gelation of polyvinyl alcohol in the ink-receiving layer-forming coating solution are moderate. By being fast, cracking and folding of the ink jet recording sheet can be suppressed. Further, since the crosslinking agent in the aqueous crosslinking agent solution is also a mordant, the water resistance of the ink jet recording sheet can be improved.
The present invention suppresses cracking during recording that has occurred in the ink-receiving layer cracks and C-type paper-feed ink jet printers, and has excellent gloss, image quality, ink absorbability, and water resistance. A recording sheet can be provided.

Claims (4)

In the method for producing an ink jet recording sheet, a coating liquid for forming an ink receiving layer containing fine particles and a polyvinyl alcohol having a polymerization degree of 2000 or more is coated on a support and dried to form an ink receiving layer. In contrast, an aqueous solution of a crosslinking agent capable of crosslinking is applied to the support prior to or simultaneously with the application of the ink-receiving layer-forming coating solution, and the crosslinking agent comprises zirconyl nitrate, zirconyl chloride, A method for producing an inkjet recording sheet, comprising at least one kind of hydroxy zirconyl chloride. The method for producing an inkjet recording sheet according to claim 1, wherein the polyvinyl alcohol has a saponification degree of 97 mol% or more. The method for producing an inkjet recording sheet according to claim 1, wherein the crosslinking agent is zirconyl nitrate or zirconyl chloride. The manufacturing method of the sheet | seat for inkjet recording as described in any one of Claims 1-3 obtained by apply | coating the aqueous solution of the said crosslinking agent before ink receiving layer formation.