JP2006264230A - Inkjet recording material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording material having excellent photographic printing paper-like tone and furthermore high ink absorbing properties as well. <P>SOLUTION: In the inkjet recording material provided with an ink receiving layer and a gloss expressing layer on at least one face of a water-absorbing substrate, the gloss developing layer comprises an inorganic ultra-finely divided particle, a water-soluble resin, and boric acid or borate, and one layer comprises a basic metal compound (A), and the other layer comprises the basic metal compound (A) and a complex salt forming compound (B) performing a complex salt forming reaction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink jet recording material, and more particularly to an ink jet recording material having gloss with excellent photographic printing paper tone and further having high ink absorbability.

  The ink jet recording method records images, characters, and the like by causing ink droplets to fly by various operating principles and adhere to a recording medium such as paper. The recording method has features such as high speed, low noise, easy multi-coloring, large flexibility of recording patterns, no need for development and fixing, etc., as a recording device for various character figures and color images including Chinese characters, etc. It is rapidly spreading in various applications. Furthermore, the image formed by the multicolor ink jet method can obtain a recording that is inferior to the printing by the multicolor printing by the plate making method or the printing by the color photographic method by expanding the resolution and the color reproduction range. In applications that require a small number of copies, the equipment required for printing is smaller and less expensive than with photographic technology, so that it is widely applied to the field of full-color image recording.

  In addition, printers and plotters that use the inkjet method are designed to increase resolution and expand the color reproduction range in order to further improve image quality from the market. We are dealing with it. Therefore, an increase in ink receiving capacity commensurate with the discharge amount is an important technical issue for the recording medium, and it is indispensable to secure a high ink receiving capacity and to apply a coating layer with good color development. . In addition, in recent years, output has been performed as an alternative to silver halide photography and commercial printing, and it is desired that the appearance and texture of gloss, rigidity, hue, etc. be similar to silver halide photography and printing paper. It is becoming.

  In order to meet these demands, in order to obtain a high-quality printed image that achieves both ink absorptivity and gloss, it is essential to have a smooth coating layer with many voids and no cracks. . In order to obtain a good ink absorbability by providing a gap in the coating layer, an ink jet recording material has been proposed in which an ink jet recording layer containing inorganic fine particles is provided on a support (for example, see Patent Document 1). In addition, for the purpose of obtaining better ink jet recording performance, an ink jet recording material provided with two or more ink receiving layers has also been proposed (for example, see Patent Document 2). In addition, for the purpose of imparting gloss, an ink jet recording material containing inorganic ultrafine particles having a smaller primary particle diameter of 3 nm to 30 nm has been proposed (see, for example, Patent Documents 3 and 4). In addition, for the purpose of obtaining particularly good ink fixability, ink absorbability, and surface gloss, an ink jet recording material containing cationic inorganic ultrafine particles as inorganic ultrafine particles has been proposed (for example, Patent Documents 5 to 5). 7).

  The ink receiving layer containing such inorganic ultrafine particles has a characteristic that it shrinks very much upon drying after coating. For this reason, the ink receiving layer tends to crack after drying. This crack has an adverse effect on the ink receiving performance of the ink receiving layer, such as ink bleeding and image density reduction due to ink drop, and also causes a reduction in surface gloss. In order to obtain good ink receiving performance and surface gloss, it is necessary to suppress cracks on the surface of the coating layer.

  Of these ink-jet recording materials, ink-jet recording materials provided with two or more ink-receiving layers are usually produced by applying the ink-receiving layer coating liquid onto a support in a plurality of times. However, since the ink receiving layer is designed to absorb a large amount of liquid, the layer applied after the second time soaks into the already applied lower layer, resulting in incomplete layer separation. Therefore, there is a problem that performance such as color density and ink absorbability cannot be sufficiently exhibited as compared with the case where each layer is formed completely separated.

  In addition, as a process for smoothing the coating layer, a method of smoothing the coating layer surface by passing paper between rolls subjected to pressure or temperature using a calendar device such as a super calendar or a gloss calendar is generally used. It is. However, when calendering is performed under high linear pressure for the purpose of imparting gloss to an ink jet recording medium, the gloss is improved, but voids in the coating layer are reduced, ink absorption is slow, and the absorption capacity is insufficient. There is a problem that the ink overflows. For this reason, in the calendar process, conditions must be selected within the range of the allowable ink absorption capacity, and it is difficult to cope with current technology to obtain ink absorption and gloss.

  As a method for imparting surface gloss without using calendar treatment, a method for producing a high-gloss coated sheet for printing generally called cast-coated paper (hereinafter abbreviated as cast treatment) is known. This casting method includes a direct method in which a coating liquid applied to a substrate is not dried at all and pressed against a heated mirror roll (hereinafter abbreviated as a cast drum), or a wet coating layer. There is known a rewetting method in which after drying once, plasticizing by rewetting and press-contacting to the cast drum, and a coagulation method in which the wet coating layer is treated with a coagulating liquid to be solidified without fluidity and pressed to the cast drum. In addition, the production of an ink jet recording material by a casting method has already been proposed (see, for example, Patent Document 8).

Among these casting methods, the direct method is such that when the wet coating layer is pressed against the cast drum, the water in the paint boils suddenly and destroys the coating layer. There is a problem that it is impossible to make it low speed operation. In the rewet method, when the coating layer is once dried, the coating layer is likely to be cracked, and the coating layer shrinks due to drying and the voids in the coating layer are reduced. It is difficult to secure. In the solidification method, the coating layer is pressed and dried on the cast drum in a plasticized solidified state without drying and solidifying the coating layer like the rewetting method. Can be formed. Even when the cast drum temperature is high, the coating layer is solidified and has high strength, so that the coating layer is not destroyed as in the direct method. However, in the coagulation method, since the coating layer is further treated with the coagulation liquid while it is in a wet state, the amount of water in the coating layer and the support is increased compared to other casting methods, and the drying load due to the cast drum is increased. However, there is a problem that the productivity is low, the wrinkles are likely to enter, or the paper is easily cut.
JP-A-55-51583 Japanese Patent Laid-Open No. 55-11829 Japanese Patent Laid-Open No. 10-203006 JP-A-8-174992 JP-A-5-50739 JP-A-6-55829 JP-A-8-207431 Japanese Patent No. 2092519

  An object of the present invention is to solve the above-mentioned problems, and to provide an ink jet recording material having an excellent gloss of photographic printing paper and having a high ink absorbability.

  As a result of studying this problem, the following invention has been found. That is, the present invention provides an ink jet recording material in which an ink receiving layer and a glossy expression layer are laminated in this order on at least one surface of a water-absorbing support, and the ink receiving layer is at least hardly soluble in water. A complex salt containing a basic metal compound (A), wherein the glossy layer has at least inorganic ultrafine particles, a water-soluble resin, boric acid or borate, and a complex salt forming reaction with the basic metal compound (A) An ink jet recording material containing the forming compound (B).

  Further, in an ink jet recording material in which an ink receiving layer and a gloss developing layer are laminated in this order on at least one surface of a water absorbing support, the gloss developing layer includes at least inorganic ultrafine particles, a water-soluble resin, a boron. A complex salt-forming compound (B) that contains an acid or borate and a basic metal compound (A) that is hardly soluble in water, and in which the ink-receiving layer reacts at least with the basic metal compound (A). ) Containing an inkjet recording material.

  Further, the gloss developing layer was coated with the coating liquid for the gloss developing layer, and the wet coating layer was heated while the coating layer was in a wet state or once dried and rewet. More preferably, the mirror finished surface is pressed and dried.

  According to the present invention, even a coating layer using inorganic ultrafine particles having good ink absorbability does not cause cracking, and a coating layer having high gloss can be provided. In addition, since the solidification reaction of the gloss developing layer occurs immediately after the gloss developing layer is coated on the ink receiving layer, the penetration of the gloss developing layer into the ink receiving layer that absorbs a large amount of liquid is suppressed, and layer separation is performed. Becomes perfect, and the ink absorbency is high and the color density is also high. Furthermore, since it is not necessary to perform the treatment with a coagulating liquid as in the coagulation method casting method, the water content of the coating layer is not increased, and the drying load is reduced, thereby improving the productivity. With the above effects, it is possible to provide an ink jet recording material having an excellent gloss of photographic printing paper tone and further having high ink absorbability.

  Examples of the water-absorbing support in the present invention include chemical pulps such as LBKP and NBKP, mechanical pulps such as GP, PGW, RMP, TMP, CTMP, CMP, and CGP, wood pulp such as waste paper pulp such as DIP, and kenaf and bagasse. Mainly non-wood pulp such as bamboo, cotton, etc. and conventionally known pigments, and one or more binders and various additives such as sizing agents, fixing agents, yield improvers, cationizing agents, paper strength enhancing agents, etc. Stencil, mixed paper, base paper manufactured by various devices such as long paper machine, circular paper machine, twin wire paper machine, etc., and base paper provided with size press or anchor coat layer with starch, polyvinyl alcohol etc. In addition, coated paper such as art paper, coated paper, cast coated paper and the like provided with a coating layer thereon is also included. In order to use such base paper and coated paper as they are, or to control flattening, a calendar device such as a machine calendar, a TG calendar, or a soft calendar may be used.

Examples of the basic metal compound (A) that is hardly soluble in water according to the present invention include metal oxides, hydroxides, carbonates, phosphates having a solubility in water at 20 ° C. of 0.5% by mass or less. Silicates, borates, aluminates and the like can be mentioned, and those represented by the formula X _m Y _n are particularly preferable. Here, X represents a metal ion having a monovalent or divalent or higher cation, and Y represents an atom or atomic group having a monovalent or divalent or higher negative ion. m and n each represent an integer such that the respective valences of X and Y can be balanced. X _m Y _n may have water of crystallization or may form a double salt. Preferably, X is Ca ²⁺ , Ba ²⁺ , Sr ²⁺ , Mg ²⁺ , Zn ²⁺ , Co ²⁺ , Ni ²⁺ , Cu ²⁺ , Mn ²⁺ or Fe ²⁺ , and Y is an oxide ion Hydroxide ions, carbonate ions, silicate ions, borate ions or aluminate ions are preferred.

Preferable specific examples of the basic metal compound hardly soluble in water represented by the formula X _m Y _n include zinc oxide, magnesium oxide, cobalt oxide, magnesium carbonate calcium, zinc hydroxide, magnesium hydroxide, calcium hydroxide. Iron hydroxide, manganese hydroxide, magnesium borate, calcium silicate, magnesium silicate, calcium aluminate, zinc aluminate, basic zinc carbonate, basic magnesium carbonate, basic nickel carbonate, basic cobalt carbonate and the like. Among these, when dispersed with a dispersion medium containing water, the dispersion liquid is preferably not colored, and zinc hydroxide is particularly preferable. The average particle diameter of the basic metal compound that is hardly soluble in water is generally preferably 20 μm or less, and more preferably 5 μm or less in view of the smoothness of the ink receiving layer. In view of the smoothness of the gloss developing layer and the reactivity with the complex salt-forming compound described later, the particle size is preferably smaller, and more preferably 5 to 100 nm. The amount added to the coating layer is preferably 0.01 to 10% by mass, more preferably 0.05 to 5% by mass.

  The complex salt-forming compound (B) that reacts with a basic metal compound (A) that is hardly soluble in water according to the present invention, preferably a complex salt-forming compound that raises the pH by a complex salt-forming reaction, comprises the above basic metal compound. A metal ion to be formed and a complex salt having a stability constant of 1 or more are generated. Specifically, aminocarboxylic acids, iminodiacetic acid and derivatives thereof, aniline carboxylic acids, pyridine carboxylic acids, aminophosphoric acids, hydroxamic acids and other alkali metals, guanidines, salts with amidines, or salts with quaternary ammonium salts Can be mentioned. The amount added to the coating layer is preferably 0.01 to 10% by mass, more preferably 0.05 to 5% by mass.

  Preferred specific examples include ethylenediaminetetraacetic acid, picolinic acid, 2,6-pyridinedicarboxylic acid, 2,5-pyridinedicarboxylic acid, 4-dimethylaminopyridine-2,6-dicarboxylic acid, quinoline-2-carboxylic acid, 2 -Alkali metal salts such as pyridylacetic acid, guanidine salts, amidine salts, quaternary ammonium salts and the like.

The method of combining the basic metal compound (A) that is hardly soluble in water and the complex salt-forming compound (B) that undergoes a complex salt-forming reaction is arbitrary, and each may be used alone or in combination of two or more. In addition, which of the ink receiving layer and the gloss developing layer may contain either component A or B, the reactivity with the other components of each layer, the presence or absence of aggregate formation, coating It can be added in consideration of the stability of the liquid and the transparency of the coating layer. When the ink receiving layer is composed of a plurality of layers, it is more effective to make the ink receiving layer present at a high concentration in the uppermost layer of the ink receiving layer in contact with the glossy expression layer. The addition amount of the coating layer A and (W _A% by mass), the amount of the coating layer B ratio (W _A / W _B) of the (W _B% by mass), is 1 / 100-100 Is more preferable, and more preferably 1 / 20-20.

  Next, other components according to the present invention will be described.

  The ink receiving layer according to the present invention is preferably composed of a coating composition mainly composed of a pigment and a binder. As the pigment used in the ink receiving layer, one or more known white pigments can be used. For example, light calcium carbonate, heavy calcium carbonate, magnesium carbonate, kaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, satin white, aluminum silicate, diatomaceous earth, silicic acid, calcium, silicic acid Magnesium, synthetic amorphous silica, colloidal silica, alumina, colloidal alumina, pseudoboehmite, aluminum hydroxide, lithopone, zeolite, hydrous halloysite, white inorganic pigments such as magnesium hydroxide, styrene plastic pigment, acrylic plastic pigment, polyethylene And organic pigments such as microcapsules, urea resins, and melamine resins. From the viewpoint of ink absorptivity, porous pigments are suitable, and synthetic amorphous silica that is excellent in terms of color developability is particularly preferably used.

  As the binder used in the ink receiving layer, starch derivatives such as oxidized starch, etherified starch, phosphate esterified starch, cellulose derivatives such as carboxymethylcellulose, hydroxyethylcellulose, casein, gelatin, soybean protein, polyvinyl alcohol or derivatives thereof, Polyvinyl pyrrolidone, maleic anhydride resin, styrene-butadiene copolymer, conjugated diene copolymer latex such as methyl methacrylate-butadiene copolymer, acrylate ester and methacrylate ester polymer or copolymer, etc. Acrylic polymer latex such as acrylic polymer, vinyl polymer latex such as ethylene vinyl acetate copolymer, or functional group-modified polymer latex with functional group-containing monomers such as carboxy groups of these various polymers, Melami Water-based adhesives such as resins, thermosetting synthetic resins such as urea resins, polymers or copolymer resins of acrylic acid esters and methacrylic acid esters such as polymethyl methacrylate, polyurethane resins, unsaturated polyester resins, vinyl chloride-vinyl acetate Examples thereof include synthetic resin adhesives such as copolymers, polyvinyl butyral, and alkyd resins. The blending amount of the binder is 3 to 70 parts by weight, preferably 5 to 50 parts by weight with respect to 100 parts by weight of the pigment. If the amount is less than 3 parts by weight, the coating layer strength of the ink receiving layer may be insufficient. If the amount exceeds 70 parts by mass, the ink absorbability may decrease.

  For the ink receiving layer, as additives, dye fixing agents, pigment dispersants, thickeners, fluidity improvers, antifoaming agents, antifoaming agents, mold release agents, foaming agents, penetrating agents, colored dyes, colored pigments , Fluorescent whitening agents, ultraviolet absorbers, antioxidants, preservatives, antibacterial agents, water resistance agents, wet paper strength enhancers, dry paper strength enhancers, and the like can be appropriately blended.

The coating amount of the ink receiving layer varies depending on the finally required surface gloss, ink absorption, type of support, etc., but is usually 1 g / m ² or more. In addition, the ink receiving layer can be applied by dividing a certain coating amount twice, and the surface gloss is improved as compared with coating the coating amount at once.

  Examples of the ink receiving layer coating apparatus include various blade coaters, roll coaters, air knife coaters, bar coaters, rod blade coaters, curtain coaters, short dwell coaters, size presses, etc., on-machine or off-machine Can be coated with machine.

  The ink receiving layer may not be calendered, but in order to obtain a particularly high surface gloss, it is desirable to calender the ink receiving layer. Examples of the calendar device include a machine calendar, a TG calendar, a super calendar, and a soft calendar. Among these, a soft calendering process is preferable because it causes little reduction in the absorption capacity of the ink receiving layer.

  The glossy expression layer of the ink jet recording material used in the present invention contains inorganic ultrafine particles, a water-soluble resin, and boric acid or borate. The inorganic ultrafine particles are inorganic fine particles having a primary particle diameter of 100 nm or less. For example, JP-A-1-97678, 2-275510, 3-281383, 3-285814, 3-285815, 4-92183, 4-267180 Alumina hydrates such as pseudo boehmite sol disclosed in Japanese Patent Laid-Open No. 4-27517, etc., vapor phase method alumina described in Japanese Patent Laid-Open No. 8-72387, Japanese Patent Laid-Open No. 60-219083, Colloidal silica as described in JP-A-61-19389, JP-A-61-188183, JP-A-63-178074, JP-A-5-51470, JP-B-4-19037, JP-A Silica / alumina hybrid sol as described in JP-A-62-2286787, JP-A-10-119423, JP 10-217601, a silica sol in which silica vapor is dispersed with a high-speed homogenizer, and other smectite clays such as hectite and montmorillonite (JP-A-7-81210), zirconia sol, Typical examples include chromia sol, yttria sol, ceria sol, iron oxide sol, zircon sol, aluminum oxide sol, and antimony oxide sol, and these can be used alone or in combination of two or more.

  In addition to the above-mentioned inorganic ultrafine particles, various organic pigments can be appropriately blended in the glossy layer of the present invention as necessary. Examples of such organic pigments include conjugated diene copolymers such as polystyrene, styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer, polymers or copolymers of acrylic acid esters and methacrylic acid esters, and microcapsules. Organic polymer fine particles such as urea resin and melamine.

  Examples of the water-soluble resin used in the glossy layer in the present invention include starch derivatives such as oxidized starch, etherified starch, and phosphate esterified starch, cellulose derivatives such as carboxymethylcellulose, hydroxymethylcellulose, and hydroxyethylcellulose, casein, gelatins, Examples include soy protein, polyvinyl alcohol, silanol-modified polyvinyl alcohol, modified polyvinyl alcohol such as acetoacetyl-modified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, polyvinyl pyrrolidone, polyethylene oxide, polypropylene oxide, polyvinyl ether, and polyacrylamide. It is not limited to these. These water-soluble resins may be used alone or in combination of two or more. Among these, polyvinyl alcohol and modified polyvinyl alcohol are preferable from the viewpoint of adhesive strength.

  The total amount of the water-soluble resin used in the glossy layer of the present invention is preferably 3 to 20% by weight, particularly 5 to 15% by weight, based on the inorganic ultrafine particles, in terms of dry solid content. It is preferable. Below the above range, the gloss-developing layer has poor film formability, and the surface of the gloss-developing layer is cracked or powdered easily, and if it exceeds the above range, the ink absorbability may be deteriorated. .

  In addition to the water-soluble resin described above, various binders can be appropriately blended in the glossy layer of the present invention as necessary. Examples of such binders include conjugated diene copolymer latex such as maleic anhydride resin, styrene-butadiene copolymer, and methyl methacrylate-butadiene copolymer, and polymers or copolymers of acrylate ester and methacrylate ester. Acrylic polymer latex such as an acrylic polymer such as a polymer, a vinyl polymer latex such as an ethylene vinyl acetate copolymer, or a functional group by a functional group-containing monomer such as a carboxyl group of these various polymers Aqueous adhesives such as modified polymer latex, thermosetting synthetic resins such as melamine resins and urea resins, polymers or copolymer resins of acrylic acid esters and methacrylic acid esters such as polymethyl methacrylate, polyurethane resins, unsaturated polyester resins , Vinyl chloride-vinyl acetate copolymer, polyvinyl butyrate Le, and the like synthetic resin adhesive such as alkyd resin.

As boric acid used in the glossy layer in the present invention, not only orthoboric acid but also metaboric acid, hypoboric acid and the like can be used. The borate is preferably a soluble salt such as Na ₂ B ₄ O ₇ .10H ₂ O, NaBO ₂ .4H ₂ O, K ₂ B ₄ O ₇ .5H ₂ O, NH ₄ HB ₄ O _{7. · 3H 2 O, NH 4 BO} 2 , and the like, but the present invention is not limited thereto. These may be used alone or in combination of two or more. The addition amount of boric acid or borate in the coating liquid for the glossy layer is 1 to 15% by mass, preferably 3 to 10% by mass, based on the water-soluble resin in terms of H ₃ BO ₃ .

  For the glossy layer, as additives, dye fixing agents, pigment dispersants, thickeners, fluidity improvers, antifoaming agents, foam suppressors, mold release agents, foaming agents, penetrants, colored dyes, colored pigments , Fluorescent whitening agents, ultraviolet absorbers, antioxidants, preservatives, antibacterial agents, water resistance agents, wet paper strength enhancers, dry paper strength enhancers, and the like can be appropriately blended.

  In this invention, it is preferable that pH of the coating liquid of a glossiness expression layer is 5.0 or less, More preferably, it is 4.5 or less, More preferably, it is 4.0 or less. The pH of the coating solution can be adjusted using various acidic aqueous solutions and alkaline aqueous solutions. When the pH of the coating solution becomes higher than 5.0, the crosslinking reaction of the water-soluble resin with the boron compound in the coating solution proceeds, causing the coating solution to thicken and gel, making uniform coating impossible. Sometimes.

There are no particular restrictions on the method of applying the coating liquid for the glossy layer, and various coating methods such as blade coaters, bar coaters, air knife coaters, reverse roll coaters, comma coaters can be used. A pre-weighing coater such as a coater or a curtain coater is preferably used from the viewpoint of the uniformity of the obtained coating layer. The coating amount of the glossy layer varies depending on the required surface gloss and ink absorbency, but may be ² g / m ² or more.

  The gloss developing layer of the present invention was coated with the coating liquid of the gloss developing layer, and the wet coating layer was heated while the coating layer was in a wet state or once dried and rewet. It is preferable to press and dry the mirror-finished surface (casting method). The casting method is subdivided into a direct method, a rewetting method, a coagulation method and the like. The direct method is a method in which after applying the glossy layer, it is pressed against a mirror roll (cast drum) heated in an undried state (wet state) and dried. The rewet method is a method in which a glossy layer is coated and dried, and then the coated layer is rewet with a wetting liquid mainly composed of water, and pressed against a cast drum and dried. The solidification method is a method in which after applying the glossy layer, the undried coating layer is solidified with a coagulating liquid, and then pressed against a cast drum and dried. The surface temperature of the cast drum is preferably in the range of 70 to 150 ° C., more preferably in the range of 80 to 120 ° C., from the viewpoint of operability such as drying conditions and the gloss of the glossy layer. The pressure linear pressure between the press roll and the cast drum for pressure contact is preferably 20 to 300 kN / m, and more preferably 30 to 250 kN / m.

  After providing the glossy expression layer of the present invention, it is also possible to correct the curl by spraying humidified air or steam on the back surface of the glossy expression layer sandwiching the water-absorbing support. Furthermore, surface gloss can be further imparted using a calendar device, a casting device, or the like. Moreover, prior to the treatment using these apparatuses, the effect of the treatment by these apparatuses can be enhanced by applying moisture to the glossy layer in advance.

  Examples of the present invention will be described below, but the present invention is not limited to these examples. In Examples and Comparative Examples, “parts” means “parts by mass” and “%” means “% by mass” unless otherwise specified.

(1) Water-absorbing support The ratio of light calcium carbonate / heavy calcium carbonate / talc is 10 to 100 parts of wood pulp comprising 80 parts of LBKP (freeness 400 mlcsf) and 20 parts NBKP (freeze 450 mlcsf). / 10/10 pigment, 0.10 parts of commercially available alkyl ketene dimer, 0.03 parts of commercially available cationic polyacrylamide, 0.80 parts of commercially available cationic starch, 0.40 parts of sulfuric acid band, Paper making was performed at a basis weight of 90 g / m ² using a net paper machine to obtain a water-absorbing support.

(2) Coating of ink-receiving layer On the surface of the water-absorbing support prepared in (1), a coating solution for ink-receiving layer (solid content concentration 16%) containing water as a solvent having the following composition is dried and applied. The ink receiving layer was provided by coating and drying with an air knife coater so that the coating amount was 8 g / m ² .
<Ink-receiving layer formulation>
Synthetic amorphous silica (Fine Seal X37B: Tokuyama) 100 parts Zinc hydroxide 10 parts Polyvinyl alcohol (PVA117: Kuraray) 30 parts Cationic fixing agent (Smileds resin 1001: Sumitomo Chemical Co., Ltd.) 20 parts

(3) Coating of gloss developing layer On the ink receiving layer prepared in (2), dry coating of a coating liquid for gloss developing layer (solid content concentration 16%) using water having the following composition as a solvent. After coating with an air knife coater so as to have an amount of 10 g / m ² and drying with hot air, soft calendering was performed to produce the ink jet recording material of Example 1.
<Glossy expression layer formulation>
Colloidal silica (Snowtex AK: manufactured by Nissan Chemical Industries) 100 parts polyvinyl alcohol (PVA117: manufactured by Kuraray) 30 parts boric acid 5 parts sodium picolinate 10 parts Cationic fixing agent (Smileds resin 1001: manufactured by Sumitomo Chemical) 20 parts Release agent 5 parts

(Comparative Example 1)
An ink jet recording material of Comparative Example 1 was prepared in the same manner as in Example 1 except that sodium picolinate was removed from the glossy layer composition in Example 1.

  In Example 1, after applying the coating liquid for the glossy layer, the ink jet recording material of Example 2 was prepared by pressing and drying on a cast drum having a surface temperature of 105 ° C. while the coating layer was wet. did.

  In Example 2, the inkjet recording material of Example 3 was produced in the same manner as in Example 2 except that the zinc hydroxide in the ink receiving layer formulation was replaced with magnesium oxide.

  In Example 2, the inkjet recording material of Example 4 was produced in the same manner as in Example 2 except that sodium picolinate in the gloss developing layer formulation was replaced with sodium ethylenediaminetetraacetate.

  In Example 2, the same procedure as in Example 2 was followed, except that the zinc hydroxide in the ink receiving layer formulation was replaced with sodium picolinate and the sodium picolinate in the gloss developing layer formulation was replaced with zinc hydroxide. An ink jet recording material was prepared.

The inkjet recording material of Example 6 was produced in the same manner as in Example 2 except that the dry coating amount of the glossy layer in Example 2 was changed to 20 g / m ² .

In Example 2, after the coating liquid for the gloss developing layer was applied on the ink receiving layer, it was once dried, and a rewetting liquid composed of water was supplied to 15 g / m ² to swell the gloss developing layer. Immediately, the ink was pressed against a cast drum having a surface temperature of 105 ° C. and dried to prepare an ink jet recording material of Example 7.

(Comparative Example 2)
In Example 2, an inkjet recording material of Comparative Example 2 was produced in the same manner as in Example 2 except that zinc hydroxide was removed from the ink receiving layer formulation.

(Comparative Example 3)
In Example 2, an inkjet recording material of Comparative Example 3 was produced in the same manner as in Example 2 except that sodium picolinate was removed from the glossy layer formulation.

(Comparative Example 4)
An ink jet recording material of Comparative Example 4 was prepared in the same manner as in Example 5 except that sodium picolinate was removed from the ink receiving layer formulation in Example 5.

(Comparative Example 5)
An ink receiving layer was provided using a coating liquid obtained by removing zinc hydroxide from the ink receiving layer coating liquid of Example 2, and a coating liquid obtained by removing boric acid and sodium picolinate from the glossy layer coating liquid. After coating on the ink receiving layer, the coating layer is wetted after being treated with a coagulating liquid composed of a borax solution having a solid concentration of 2.0% while the glossy layer is fluid. In the meantime, it was pressed against a cast drum having a surface temperature of 105 ° C. and dried to produce an inkjet recording material of Comparative Example 5.

  The ink jet recording materials produced in Examples 1 to 7 and Comparative Examples 1 to 5 were subjected to the following evaluation. The evaluation results are shown in Table 1.

[Surface gloss]
The surface glossiness is the ink jet recording material produced in Example 1 and Comparative Example 1 by using a digital gloss meter GM-26D type manufactured by Murakami Color Research Laboratory according to the specular gloss measurement method defined in JIS Z8741 and P8142. Was measured for 75 degree specular gloss, and the ink jet recording materials produced in Examples 2 to 7 and Comparative Examples 2 to 5 were measured for 20 degree and 75 degree specular gloss, respectively.

[Crack on surface of glossy layer]
The surface of the produced inkjet recording material was evaluated by observing with an optical microscope. ◎ is a level where there is no crack, ○ is a level where cracks are scattered and seen as a straight line, but is acceptable level, △ is a level where many cracks are seen on the entire surface, × is a level where many cracks are seen, and is not acceptable as a product Is a level.

[Print density, ink absorbency]
The print density and ink absorbency were determined by printing an image using a Seiko Epson printer (PM-750C). The image used for the evaluation is composed of a black, cyan, magenta, yellow, blue, red, green 100% solid printing portion, and a pattern in which white characters are provided. The print density was measured on a black solid print using a densitometer (Macbeth RD918). The ink absorptivity was evaluated by visually observing the uniformity in a solid print portion, the boundary between adjacent solid print portions, the sharpness of white characters, and the like. Excellent ink absorption. ○ is a level where there is no problem in practical use, although the solid print portion is uneven and white characters are crushed slightly. Δ is a level at which the blurring of the border portion of the solid print portion and the crushing of the white characters are conspicuous. X is a level at which printing failure due to insufficient ink absorption is observed.

[Operability]
The operability was evaluated by visually checking the stain on the cast drum for the ink jet recording materials produced in Examples 2 to 7 and Comparative Examples 2 to 5. ○ indicates that the cast drum is clean. Δ indicates a slight transfer of the glossy layer on the surface of the cast drum, but there is no practical problem. X indicates a level at which the glossy layer is transferred to the surface of the cast drum, and a portion where the glossy layer is peeled off is observed on the surface of the obtained ink jet recording material, or paper breakage occurs during operation.

Rating:
As is clear from Table 1, the inkjet recording material of the present invention of Example 1 has no cracks on the surface of the glossy layer, has a high 75-degree reflection angle gloss value, high print density, and excellent ink absorption. It was. On the other hand, in Comparative Example 1, since there was no complex salt forming compound, the gloss developing layer was submerged in the ink receiving layer, the layer separation was incomplete, many cracks were generated on the surface, and gloss was lowered. Furthermore, there were few voids inside the coating layer, and the ink absorbency was poor. The inkjet recording materials of the present inventions of Examples 2 to 7 have no operational problems in the casting process, have no cracks in the glossy layer, and have a high 75 ° reflection angle gloss value and a 20 ° reflection angle gloss value. It had excellent surface gloss. The print density was high and the ink absorbency was excellent. On the other hand, when the basic metal compound or the complex salt forming compound is removed as in Comparative Examples 2 to 4, the gloss-expressing layer is not solidified, so that the strength is weak, and when the coating layer is pressed against the cast drum, The coating layer burst (punctures) due to excessive evaporation of moisture, and transfer of the glossy layer was observed on the surface of the cast drum, and many portions where the glossy layer was peeled off were also observed on the surface of the obtained ink jet recording material. . Further, the gloss developing layer was submerged in the ink receiving layer, resulting in incomplete layer separation, many cracks were generated on the surface, and the gloss was lowered. Furthermore, there were few voids inside the coating layer, and the ink absorbency was poor. Further, in Comparative Example 5 produced by the conventional coagulation method casting method, paper breakage frequently occurred during operation, and stable production was difficult. Further, since the glossy layer was slightly submerged into the ink receiving layer, the surface was cracked and the print density was low.

Claims (3)

  In an ink jet recording material in which an ink receiving layer and a glossy expression layer are laminated in this order on at least one surface of a water-absorbent support, the ink receiving layer is a basic metal compound (A And the gloss-expressing layer contains at least inorganic ultrafine particles, a water-soluble resin, boric acid or a borate, and a complex salt-forming compound (B) that undergoes a complex salt-forming reaction with the basic metal compound (A). An ink jet recording material containing the ink jet recording material.   In an ink jet recording material in which an ink receiving layer and a gloss developing layer are laminated in this order on at least one surface of a water-absorbing support, the gloss developing layer contains at least inorganic ultrafine particles, a water-soluble resin, boric acid or A complex salt-forming compound (B) containing a borate and a basic metal compound (A) that is hardly soluble in water, and in which the ink receiving layer reacts at least with the basic metal compound (A). An ink jet recording material containing the ink jet recording material.   The gloss developing layer is coated with a coating solution for the gloss developing layer, and while the coating layer is in a wet state or once dried and rewet, the wet coated layer is heated to a mirror finish. 3. The ink jet recording material according to claim 1, wherein the surface is press-contacted and dried to finish.