JP2012116114A - Ink jet recording body and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording body having excellent recording adequacy with respect to both dye ink and pigment ink and excellent fretting resistance of the pigment ink.SOLUTION: In the ink jet recording body having an ink fixation layer arranged on a support body, the ink fixation layer includes: a minute pigment; an adhesive for fixing the minute pigment to the support body; a cross-linking agent and a cationic ink fixing agent suppressing cracks of the ink fixation layer by cross-linking part of the adhesive; and silicone acrylic resin or silicone oil.

Description

  The present invention relates to an ink jet recording material, and more particularly to an ink jet recording material having excellent recording suitability for both dye ink and pigment ink, and excellent scratch resistance of the pigment ink.

The ink jet recording method that forms an image by ejecting ink droplets from fine nozzles and depositing them on the surface of the recording medium has low noise during recording, easy formation of full-color images, and high speed It is widely used in terminal printers, facsimiles, plotters, form printing, and the like due to the fact that recording is possible and the recording cost is lower than other printing apparatuses.
In recent years, inkjet printers have become higher in definition and speed, and have been widely spread to general household users for the purpose of outputting captured images using a digital camera or the like.

Ink jet recording bodies are required to have high image quality such as color developability and depth of the ink jet recording image in order to bring the quality of the recording image obtained by outputting the photographed image close to that of a silver salt photograph. In addition, high ink absorptivity corresponding to high speed ink jet printers is required. In order to obtain high ink absorptivity, it is necessary to increase the coating amount of the ink fixing layer. For example, as described in Patent Document 1, normally, when an ink fixing layer having a high coating amount (dry film thickness of 30 μm or more) is formed, the film thickness of the coating liquid is 100 μm or more. When the aqueous coating liquid is coated on the support with such a high wet film thickness and dried, there is a problem that the ink fixing layer tends to crack.
The reason is presumed as follows. When a coating liquid for an ink fixing layer is applied on a substrate and hot air is applied for drying, the drying starts from the surface of the coating liquid and is finally dried to the inside of the coating layer. Therefore, when only the coating liquid surface is dried and formed into a film, it contains a large amount of moisture. Next, volume shrinkage occurs when the moisture in the interior escapes, but the dried surface layer is a hard film, so it cannot absorb the strain of volume change and cracks occur.

When the ink fixing layer has cracks, particularly when printing is performed with a pigment ink printer, the pigment particles in the ink fall into the cracks, and a sufficient recording density cannot be obtained. Therefore, in order to obtain a particularly high quality image, the ink fixing layer should never crack.
On the other hand, when printing is performed with a dye ink printer, if the support is a paper base, the support reaches the paper base due to the moisture of the ink, and thus swells. Once expanded, the paper substrate returns to its original volume due to the evaporation of moisture, but it does not have the same shape as before, and is distorted. If there is a crack in the ink fixing layer, the ink fixing layer also follows the surface shape of the paper base, so there is a difference in glossiness between the white paper portion and the printed portion, and the portion with a large amount of ink applied and the portion with a small amount of ink. Is produced. When there is no crack, when the ink fixing layer is integrated, even if the paper base material is somewhat blurred, the entire layer is a single surface, so it is difficult to adversely affect glossiness and image clarity.

In order to avoid such cracking of the ink receiving layer, in Patent Document 1, a non-absorbent support is used as the support, and after coating and drying a coating liquid for forming the first porous layer thereon, It has been proposed to apply and dry a coating liquid that forms a second porous layer having a dry film thickness that is smaller than that of the first porous layer. However, forming a large number of ink receiving layers thinly and laminating these layers has a high process cost and may cause problems economically. Further, the above publication does not describe any means effective for obtaining a thick film thickness with as few cracks as possible.
Further, in Patent Document 2, a coating liquid containing boric acid is applied on a support or a first coating layer, and a second coating layer containing a material that crosslinks boric acid is applied thereon. However, the boric acid moves into the second coating layer to gel the second coating layer, and the gel layer is trying to solve the problem by reducing the volume change that occurs during the drying process. Because of the slow reaction rate, it is difficult to say that it is fully effective now.

  Further, since the pigment ink stays on the surface of the ink jet recording body, the ink may be peeled off if it is rubbed with something after printing. In particular, in the case of applications such as postcards, there is a high possibility of rubbing against moving parts of the device and other postal items in the process of collection and delivery, sorting, postmarking, etc., so higher scratch resistance is required. Yes. Since the scratch resistance tends to be inferior as the surface of the recording material has no cracks and becomes smoother, it is difficult to achieve both printability and scratch resistance.

JP 2000-301828 A Japanese Patent Laid-Open No. 2003-231342 Japanese Patent No. 3487696 Japanese Patent No. 3745826 Patent No. 4042405 Patent No. 4290400 Japanese Patent No. 4404175

  It is an object of the present invention to provide both printability and scratch resistance in order to provide an ink jet recording material excellent in both dye ink and pigment ink with excellent recording suitability and excellent pigment ink scratch resistance. .

  As a result of intensive studies, the present inventors have found that in an ink jet recording body in which an ink fixing layer is provided on a support, the ink fixing layer is a fine pigment, an adhesive, a crosslinking agent capable of reacting with an adhesive, and a cationic ink. Including a silicone acrylic resin or silicone oil as a fixing agent and a pigment ink scratch resistance improving agent, it has been found that excellent recording suitability and pigment ink scratch resistance can be achieved, and the present invention is completed. It came.

As examples of using a silicone compound in an ink jet recording material, the following patent documents are known.
Patent Document 3 proposes an ink fixing layer containing pigments and water-repellent resin particles to control ink absorbency and dot diameter spread. However, in this document, the expected effect cannot be obtained with a silicone emulsion or water-based silicone resin (described in [0007]), and cracking of an ink fixing layer, which is important as pigment ink suitability, is not considered. The object, idea, means, and effect are all different from the present invention.
Patent Document 4 proposes a method in which the entire surface of an ink jet recording body is covered with a water-repellent material such as a silicone emulsion, and the figures are shown as [FIG. 6] and [FIG. 7]. However, as in this document, coating the entire surface with a water-repellent material may adversely affect ink absorbency, and cracking of the ink receiving layer, which is important for pigment ink suitability, is not considered. In light of this technical level, it is difficult to say that both good printability and scratch resistance are compatible.

In Patent Document 5, a method of coating an ink fixing layer after aging a coating liquid containing a polyvinyl alcohol (hereinafter referred to as PVA) resin, a melamine crosslinking agent, a surfactant, and silica particles under certain conditions, and surface activity It has been proposed to use a silicone-based agent. However, in this document, for the purpose of improving water resistance (described in [0008]), a crosslinking agent is blended or a primer layer is provided, which makes it difficult to prevent cracks on the surface of the coating layer. .
Patent Document 6 proposes a method of covering the surface with a ladder type silicone resin after recording, but is different from the present invention in all of the purpose, idea, means, and effect.
As described above, all of the ink jet recording materials described in the above-mentioned patent documents cause a cross-linking reaction to efficiently occur after application of the ink fixing layer and before the drying process, and the volume change of the coating layer in the drying process. The present situation is that there is no material that suppresses cracking of the coating layer to prevent cracking, and furthermore, there is no material that achieves both scratch resistance and recording suitability of the pigment ink.

The present invention is as follows.
(1) In an ink jet recording medium in which an ink fixing layer is provided on a support, the ink fixing layer is crosslinked with a fine pigment, an adhesive for fixing the fine pigment to the support, and a part of the adhesive. An ink jet recording material comprising a crosslinking agent and a cationic ink fixing agent for suppressing cracking of an ink fixing layer, and further containing a silicone acrylic resin or silicone oil.
(2) The ink jet recording material according to (1), wherein the adhesive contained in the ink fixing layer is a polyvinyl alcohol resin, and the crosslinking agent is a boron compound.
(3) Use as a postcard of the ink jet recording material according to (1) or (2) above.

(4) A liquid containing borax as a cross-linking agent is applied as a first coating layer on the support, and further contains a fine pigment, a polyvinyl alcohol resin and a cationic ink fixing agent, and further includes silicone. A coating liquid containing acrylic resin or silicone oil is applied as the second coating layer, and borax contained in the first coating layer is infiltrated into the second coating layer to obtain a polyvinyl alcohol resin. A method for producing an ink jet recording material, wherein the ink fixing layer is formed by crosslinking.
(5) A liquid containing borax as a crosslinking agent is applied as a first coating layer on the support, and a coating liquid containing a fine pigment, a polyvinyl alcohol-based resin, and a cationic ink fixing agent is formed thereon. Coating as the second coating layer, allowing the borax contained in the first coating layer to penetrate into the second coating layer to crosslink the polyvinyl alcohol resin, and then silicone acrylic resin or silicone oil A method for producing an ink jet recording material, wherein an ink fixing layer is formed by coating and impregnating a coating solution containing an ink.

(6) On the support, a liquid containing an alkaline substance is applied as a first coating layer, and further contains a fine pigment, a polyvinyl alcohol resin, boric acid and a cationic ink fixing agent as a crosslinking agent, Further, a coating liquid containing a silicone acrylic resin or silicone oil is applied as a second coating layer, and an alkaline substance contained in the first coating layer is infiltrated into the second coating layer, thereby boric acid. And a polyvinyl alcohol resin is crosslinked to form an ink fixing layer.
(7) A liquid containing an alkaline substance is applied as a first coating layer on a support, and a fine pigment, a polyvinyl alcohol resin, and a coating containing boric acid and a cationic ink fixing agent as a cross-linking agent. The liquid is applied as a second coating layer, an alkaline substance contained in the first coating layer is permeated into the second coating layer to activate boric acid, and the polyvinyl alcohol resin is crosslinked, A method for producing an ink jet recording material, comprising forming an ink fixing layer by coating and impregnating a coating liquid containing a silicone acrylic resin or silicone oil.

  According to the present invention, it is possible to provide an ink jet recording material that has excellent recording suitability for both dye ink and pigment ink, and excellent scratch resistance of the pigment ink. The ink jet recording material can be used not only as an ink jet recording material for dye ink and an ink jet recording material for pigment ink, but also as an ink jet recording material for both dye ink and pigment ink. In addition, since this ink jet recording material has excellent scratch resistance even when used for postcard applications, it may rub against movable parts of the device and other postal items in the process of collection, delivery, sorting, postmarking, etc. But it can be tolerated enough.

  In the present invention, the ink fixing layer provided on the support uses a fine pigment, the adhesive for fixing the fine pigment to the support is cross-linked by a cross-linking agent, and cracks are suppressed, The ink jet recording material satisfies the requirements of containing a cationic ink fixing agent and containing a silicone acrylic resin or a silicone oil as a scratch resistance improving agent for pigment ink.

<Support>
As the support, a support known as an ink jet recording material can be used. For example, a paper base material, a resin film, a nonwoven fabric, a cloth, or a laminated body thereof (for example, laminated paper) can be exemplified. Also included are surfaces on which inkjet recording is performed, such as CD and DVD label surfaces. Among them, the paper base material is suitable because the effect of the present invention appears remarkably because the paper base material tends to be affected by the swelling of the water of the recording ink. In addition, it is preferable to use a paper base material from the viewpoints of ease of handling as a recording medium, ease of disposal, use as a postcard, and the like. Hereinafter, a paper substrate is exemplified as a representative of the support.

[Paper base]
As the paper substrate, a commonly used known paper substrate can be used. For example, fine paper, art paper, coated paper, cast coated paper, craft paper, baryta paper, paperboard, impregnated paper, vapor-deposited paper , Fancy paper. Further, acid paper, neutral paper, etc. used for general coated paper can be used as appropriate.

  The paper base material contains wood pulp as a main component, and fillers, various auxiliaries and the like are added as necessary. As the wood pulp, various chemical pulps, mechanical pulps, recycled pulps and the like can be used. In particular, softwood and hardwood kraft pulp, or softwood bleached kraft pulp bleached from these kraft pulp (referred to as NBKP) and hardwood bleached kraft pulp (referred to as LBKP) are preferable. In addition, in these pulps, chlorine-free pulp from which the influence of chlorine has been removed in the bleaching process, for example, ECF (Elemental Chlorine Free) pulp using chlorine compounds without using chlorine itself for pulp bleaching, and chlorine element in pulp bleaching. It is preferable to use TCF (Total Chlorine Free) pulp or the like using a bleaching agent not contained at all.

  The paper substrate for postcard use is not particularly limited, and single-layer or multi-layer paper can be used. When a large amount of recycled pulp or mechanical pulp is blended, for example, a large amount of recycled pulp or mechanical pulp is used for the inner layer, and a layer containing a large amount of high whiteness pulp such as LBKP or NBKP is laminated on the front layer or the back layer. It is preferable to use three or more layers of laminated paper.

  These pulps can be adjusted by a beating machine to adjust paper strength, papermaking suitability, etc., and the beating degree (CSF (Canadian Standard Freeness)) is not particularly limited, but is 250 to 550 ml (JIS). -P8121) is preferred.

As the filler added to the paper substrate, for example, light calcium carbonate, heavy calcium carbonate, calcined kaolin, synthetic zeolite, silica, titanium oxide, talc and the like are preferably used. Among them, light calcium carbonate, calcined kaolin, and synthetic zeolite are preferable because they are porous and have excellent ability to absorb the solvent in the ink ejected from the ink jet printer. Among them, light calcium carbonate is a paper base having high whiteness. A material is obtained, which is preferable as an ink jet recording material.
As for the content rate (ash content) of the filler in a paper base material, about 1-20 mass% is preferable. Within this range, smoothness, air permeability, paper strength, and rigidity are balanced, and an ink jet recording body excellent in balance of glossiness, image clarity, and rigidity is easily obtained.

Examples of the auxiliary agent added to the paper substrate include a sizing agent, a fixing agent, a paper strength enhancer, a cationizing agent, a yield improver, a dye, and a fluorescent brightening agent.
As the sizing agent, known sizing agents such as reinforced rosin and alkenyl succinic anhydride are used.
In addition, a sulfuric acid band is used as a fixing agent for the sizing agent, and starch is used as a fixing yield improving agent in combination with the sizing agent.

  The paper substrate may be subjected to size press treatment. The purpose of the size press is to control the sizing degree, increase paper strength, smoothing, etc. The size press solution contains starches, polyvinyl alcohols, sizing agents, various pigments, etc., which are known and used in accordance with the respective purposes. Material is used. About 1 to 300 seconds are preferable, and the Stecchito sizing degree (JIS-P8122) of the paper base material is more preferably 4 to 200 seconds. If the sizing degree is less than 1 second, there is a risk of operational problems such as wrinkling during coating, and if it exceeds 300 seconds, the ink absorbability may decrease, and curling and cockling after printing. (Absorption wrinkles) may be remarkably unfavorable.

Although the basic weight of a paper base material is not specifically limited, About 20-500 g / m < ² > is preferable. 10-350 seconds are preferable, as for the Oken type air permeability (Japan TAPPI No. 5) of a paper base material, 10-200 seconds are more preferable, and 20-100 seconds are still more preferable. If the air permeability is less than 10 seconds, the ink fixing layer coating liquid may permeate excessively into a support made of a paper substrate. In addition, when performing a glossy finish by the casting method, it is preferable to use a material having an air permeability of 350 seconds or less without impairing the operability when press-finishing the cast drum. The paper substrate is manufactured by a long net paper machine or the like, and the thickness thereof is not particularly limited, but is appropriately selected in the range of 20 μm to 500 μm depending on the application.

<Ink fixing layer>
The ink fixing layer is a coating layer having an ability to fix a color material on a support. The ink fixing layer includes a fine pigment, an adhesive for fixing the fine pigment to a support, a crosslinking agent that suppresses cracking of the ink fixing layer by crosslinking with a part of the adhesive, a cationic ink fixing agent, In addition, at least a silicone acrylic resin or a silicone oil is included as a scratch resistance improving agent for the pigment ink. The ink fixing layer is not limited to one layer, and two or more ink fixing layers may be provided as necessary. In the case of the gloss type, a cast layer may be provided by further providing a gloss imparting layer on the ink fixing layer. An undercoat layer may be provided between the ink fixing layer and the support for the purpose of preventing the ink solvent from penetrating and improving smoothness.

[Fine pigment]
As the fine pigment of the ink fixing layer, a fine secondary pigment having an average particle diameter of 10 nm to 3 μm is used. It is preferably selected from silica, alumina, and alumina hydrate. Since alumina and alumina hydrate have a higher refractive index than silica, the recording density may be lower than that of silica particularly in an ink jet printer using a dye-based ink. Accordingly, among these pigments, silica is particularly preferable, and vapor phase silica having a primary particle diameter of 5 nm to 50 nm and a secondary particle diameter of 10 nm to 300 nm is more preferable.
Further, the silica is preferably silica-cationic compound aggregate particles obtained by mixing silica and a cationic compound, and this aggregate fine particle having an average particle diameter of 10 nm to 2 μm is obtained by pulverizing and dispersing this. Used as The cationic compound and silica-cationic compound aggregate particles act as an ink fixing agent, and will be described in detail in the section of the ink fixing agent.
The aggregate fine particles most preferably have an average particle size in the range of 30 to 500 nm. If the particle diameter is less than 10 nm, the ink absorbability may be lowered. If it exceeds 1 μm, the transparency of the coating film is inferior, and the print density may be significantly lowered.

  The average particle diameter here is a median diameter of a particle diameter distribution measured using an apparatus based on a dynamic light scattering method, and the present inventors have described a “dynamic light scattering particle size distribution measuring apparatus LB-500”. “Type (manufactured by Horiba, Ltd.)” is used, but if the measurement principle is the same, almost the same value can be obtained even if the model of the apparatus is different.

  In the ink fixing layer, a known pigment used for a normal recording material can be used in combination with the pigment having an average particle diameter of 10 nm to 10 μm within a range not impairing the effects of the present invention. These pigments include kaolin (containing clay), calcium carbonate, titanium oxide, zinc oxide, amorphous silica (containing colloidal silica), aluminum oxide, zeolite, sepiolite, smectite, synthetic smectite, magnesium silicate, magnesium carbonate, oxidation Magnesium, diatomaceous earth, styrene plastic pigment, hydrotalcite, urea resin plastic pigment, benzoguanamine plastic pigment and the like can be mentioned, and these can be used alone or in combination.

[adhesive]
The adhesive is blended to fix the fine pigment to the support. As the adhesive, a water-dispersed adhesive or a water-soluble adhesive can be used alone or in combination. Examples of water-dispersed adhesives include styrene-butadiene copolymer resins, methyl methacrylate-butadiene copolymer conjugated diene resins, acrylic resins, and vinyl resins such as ethylene-vinyl acetate copolymer resins. . Among these, acrylic resins and urethane resins are particularly preferable in terms of ink absorbability and transparency of the resulting coating film. These water-dispersed adhesives may be used alone or in combination of two or more.

  Examples of water-soluble adhesives include proteins such as casein, soybean protein, gelatin, and synthetic protein, various starches such as starch and oxidized starch, various polysaccharides such as chitin and chitosan, polyvinyl alcohol, cationic polyvinyl alcohol, and silyl modification. Examples thereof include polyvinyl alcohols containing modified polyvinyl alcohol such as polyvinyl alcohol, cellulose derivatives such as carboxymethyl cellulose and methyl cellulose, aqueous polyurethane resins, and aqueous polyester resins.

  Among these adhesives, it is preferable to use polyvinyl alcohols in terms of excellent surface strength and rapid gelation by crosslinking with a crosslinking agent described later. Polyvinyl alcohol has different properties depending on the degree of saponification, and it is preferable to select the degree of saponification according to the purpose. When polyvinyl alcohol having a saponification degree of 95% or more, more preferably 98% or more is used, the strength of the coating layer is increased and foaming does not occur during the preparation of the coating solution. It is good. In addition, when partially saponified polyvinyl alcohol having a saponification degree of 75 to 90% is used, the coating layer has excellent flexibility and is very effective in preventing the breakage. These polyvinyl alcohols having different saponification degrees may be used alone or in combination depending on the purpose.

  In addition, when the polymerization degree of the polyvinyl alcohol is low, the strength of the ink receiving layer is weakened, and cracking is likely to occur, and paper powder tends to be generated at the time of cutting. When the polymerization degree is high, sufficient ink absorbability is obtained. In addition to being difficult, the solution viscosity is high and the handling surface in the coating liquid adjustment tends to be difficult. Therefore, the degree of polymerization is preferably 3000 or more, particularly preferably 3500 to 5000.

  When the amount of the adhesive of the ink fixing layer is too small, sufficient film strength cannot be obtained, and when it is excessive, the ink absorbability is lowered. It is preferable that it is 50 mass parts, and it is more preferable that it is 10-40 mass parts.

[Ink fixing agent]
The ink fixing agent has a function of fixing a dye pigment in the ink for ink jet recording, and thereby imparts water resistance to the printed image. A cationic compound is used for the ink fixing agent, and examples thereof include a cationic resin, a low molecular weight cationic compound, and a metal compound. Cationic resins are preferred in terms of improving printing density, and various known cationic resins that are generally used in ink jet recording materials can be used.

Examples of these cationic resins include (a) polyalkylene polyamines such as polyethylene polyamine and polypropylene polyamine or derivatives thereof, and (b) an acrylic heavy group having a secondary or tertiary amino group or a quaternary ammonium group. Or acrylamide copolymers thereof, (c) polyvinylamine and polyvinylamidines, (d) dicyan-based cationic compounds represented by dicyandiamide-formalin copolymer, (e) dicyandiamide-polyethyleneamine copolymer (E) epichlorohydrin-dimethylamine copolymer, (to) diallyldimethylammonium-SO ₂ polycondensate, (thi) diallylamine salt-SO ₂ polycondensate, (li) diallyl Dimethylammonium black (U) allylamine salt copolymer, (l) dialkylaminoethyl (meth) acrylate quaternary salt copolymer, (e) acrylamide-diallylamine copolymer, (wa) 5-membered ring amidine structure. And a cationic resin. In the embodiment of the present invention, these ink fixing agents are used alone or in combination of two or more.

  Examples of the low molecular weight cationic compound include silane-based, titanate-based, aluminum-based, and zirconium-based cationic coupling agents and cationic surfactants. Examples of metal compounds include water-soluble aluminum compounds (for example, aluminum chloride or hydrates thereof, aluminum sulfate or hydrates thereof, inorganic salts such as ammonium alum, polyaluminum hydroxide compounds that are inorganic aluminum-containing cationic polymers, etc. ), Water-soluble zirconium compounds (eg, zirconium acetate, zirconium chloride, zirconium oxychloride, zirconium zirconium chloride, zirconium nitrate, basic zirconium carbonate, zirconium hydroxide, zirconium carbonate / ammonium, zirconium carbonate / potassium, zirconium sulfate, fluoride) Zirconium compounds, etc.), water-soluble titanium compounds (eg, titanium chloride, titanium sulfate, etc.), water-soluble lanthanoid compounds (eg, cerium chloride, cerium nitrate, cerium sulfate, cerium acetate) Arm, and the like water-soluble polyvalent metal salt such as lanthanum nitrate, etc.). These ink fixing agents are used alone or in combination of two or more.

(Silica-cationic compound aggregate fine particles)
The cationic compound aggregates with the gas phase method silica in a mixed solution with the gas phase method silica to form a silica-cationic compound aggregate. For this reason, this cationic compound is preferably used in the form of agglomerates with gas phase method silica in advance rather than being used alone. By the way, the silica-cationic compound aggregate is pulverized and dispersed to form silica-cationic compound aggregate fine particles having an average particle diameter of 0.01 to 1 μm, and is used in a coating liquid for an ink receiving layer. The single-phase vapor phase silica used for forming the silica-cationic compound aggregated fine particles is a primary particle having an average particle diameter of 3 to 40 nm. The aggregated fine particles are substantially composed of primary particles. It consists of secondary particles formed by agglomeration.

An outline of a method for producing silica-cationic compound aggregate fine particles will be described.
The addition amount of the cationic compound is adjusted in the range of 1 to 30 parts by mass, preferably 5 to 20 parts by mass with respect to 100 parts by mass of the vapor phase method silica. When a cationic compound is added to and mixed with the vapor phase silica dispersion, a thickened aggregate dispersion is obtained. Alternatively, it can also be obtained by adding vapor phase silica to an aqueous solution of a cationic compound.
When the silica-cationic compound aggregate particles have a large particle size, they can be pulverized and dispersed to form fine particles. As a method for making fine particles, a breaking down method (a method of subdividing the bulk material) that applies a strong force by mechanical means is employed. Examples of the mechanical means include an ultrasonic wave, a high-speed rotating mill, a roller mill, a container driving medium mill, a medium stirring mill, a jet mill, a crusher, a sand grinder, a nanomizer (trade name), and a homomixer.

  The silica-cationic compound aggregated fine particles as a pigment and an ink fixing agent are used singly or in combination of two or more. By using this, the transparency, surface strength, smoothness of the ink fixing layer is used. As well as ink absorbency, color developability, weather resistance, water resistance, and the like.

  As a cationic compound, the cationic compound used by the said silica-cationic compound aggregate can be illustrated, Among these, the water-soluble resin or the thing of an emulsion is used preferably. In addition, a cationic compound, particularly a cationic resin, blended as a simple substance is often used when a role as an adhesive is also given.

(Crosslinking agent)
The ink fixing layer contains a crosslinking agent that suppresses cracking of the ink fixing layer by crosslinking with a part of the adhesive. The ink fixing layer, for example, exhibits a reduced rate of drying at the same time that the ink fixing layer coating liquid is applied or during the drying of the coating liquid layer to which the ink fixing layer coating liquid has been applied. If the coating liquid is thickened or cross-linked with a cross-linking agent before manufacturing the film, cracking can be suppressed. Therefore, the crosslinking agent may be blended in the coating solution for the ink fixing layer or may be applied separately.

  Various known crosslinking agents and gelling agents can be used as the crosslinking agent. Examples of the compound having a crosslinking property to polyvinyl alcohol include aldehyde-based crosslinking agents such as glyoxal, epoxy-based crosslinking agents such as ethylene glycol diglycidyl ether, vinyl-based crosslinking agents such as bisvinylsulfonylmethyl ether, boric acid and borax. Examples include boron-containing compounds, glycidyl compounds, zirconium compounds, aluminum compounds, chromium compounds and the like. Among these, a boron-containing compound is particularly preferable because thickening or gelation occurs quickly.

The boron-containing compound is an oxygen acid having a boron atom as a central atom and a salt thereof. Specific examples include orthoboric acid, metaboric acid, hypoboric acid, tetraboric acid, pentaboric acid, and sodium salts, potassium salts, and ammonium salts thereof. Among these, orthoboric acid and disodium tetraborate are preferably used because they have an effect of appropriately thickening the coating liquid.
In particular, orthoboric acid generally called boric acid is preferable for the following reasons. Boric acid (H ₃ BO ₃ ) does not react with polyvinyl alcohol, reacts with polyvinyl alcohol in the form of borate ions ([H ₄ BO ₄ ] −), and crosslinks it. Boric acid becomes a borate ion in the presence of alkali. Therefore, even when polyvinyl alcohol and boric acid are allowed to coexist in the ink fixing layer coating liquid, the crosslinking reaction does not occur as it is, and the coating liquid does not gel. When this ink fixing layer coating liquid is applied onto a coating layer containing an alkaline substance, the ink fixing layer rapidly gels.

  Although content of a boron compound is based also on the polymerization degree and drying condition of a boron compound and polyvinyl alcohol, it is preferable to contain 5-15 parts as boric acid with respect to polyvinyl alcohol. When the content is less than 5 parts, the rate of crosslinking and gelation of polyvinyl alcohol is slowed, so that it is necessary to reduce the coating speed or moderate drying, and the productivity tends to be inferior. On the other hand, if it exceeds 15 parts, the speed of crosslinking and gelation is increased and the productivity is excellent, but the ink fixing layer tends to be hard and brittle, which may cause quality problems.

[Silicone acrylic resin and silicone oil]
In the ink fixing layer, a silicone acrylic resin or silicone oil is blended as a scratch resistance improving agent for pigment ink. Silicone acrylic resins and silicone oils probably contribute to improving the scratch resistance of pigment inks. Silicone acrylic resins and silicone oils that have both hydrophilic fine pigments and hydrophilic / hydrophobic properties in the ink fixing layer are probably Therefore, it is presumed that the hydrophilic portion of the silicone acrylic resin or silicone oil is directed to the fine pigment, and the hydrophobic portion is directed to the opposite direction to the fine pigment, that is, the surface layer direction. In this state, when a droplet of pigment ink comes from an inkjet printer, the droplet penetrates between the hydrophilic fine pigment and the hydrophilic part of the silicone acrylic resin or silicone oil, and the coloring material stays on the surface. The solvent penetrates and is absorbed inside the ink fixing layer. Then, after the ink is dried, the ink coloring material is appropriately protected by the hydrophobic portion present on the surface layer, so that it is presumed that the scratch resistance is improved.

  Since the silicone acrylic resin and silicone oil need only be present on the surface of the ink fixing layer, it may be formed by blending with the ink fixing layer coating liquid. After forming the ink fixing layer, coating / impregnation May be provided. A plurality of silicone acrylic resins and silicone oils may be used in combination.

(Silicone acrylic resin)
There are various types of silicone acrylic resins as described below.
(1) A W / O / W emulsion obtained by wrapping an acrylic resin with silicone oil and dispersing it in water.
(2) A silicone acrylic resin obtained by reacting an acrylic resin containing a tertiary amino group with an epoxy group-containing silicone compound.
(3) A product obtained by reacting a carboxyl group of an acrylic resin with a silanol group of an alkylpolysiloxane and grafting the alkylpolysiloxane to the acrylic resin.

In the present invention, all of the above can be used, but the above (1) may cause troubles such as repellency when the emulsion is broken due to interaction with other additives contained in the fixing layer coating solution. In the above (2), since the reactive functional group may react with other additives in the fixing layer and cause trouble, the silicone acrylic resin prepared by the method (3) is easy to handle, Preferably used. In the present invention, the amount of the silicone acrylic resin added to the fixing layer is preferably 0.05 to 0.5 g / m ² . When the amount is less than 0.05 g / m ^2, there is a possibility that abrasion resistance can not be sufficiently exhibited, when it exceeds 0.5 g / m ² in the reverse is likely to deteriorate the absorption of the ink.

(Silicone oil)
Silicone oil is a substance having a polyalkylsiloxane structure, in which the alkyl group is hydrophobic and the oxygen of the siloxane is hydrophilic, and the number of alkyl groups, the number of carbons in the alkyl group, and the degree of polymerization are appropriately determined according to the required properties. Select and use.
In the present invention, the ink fixing layer coating liquid is water-based, and the ink for ink jet printers is also mostly water-based, and so strong hydrophobicity is not preferable. Accordingly, polydimethylsiloxane having 2 alkyl groups and 1 carbon atom in the alkyl group is preferably used. In the present invention, the amount of silicone oil added to the fixing layer is preferably 0.02 to 0.2 g / m ² . If the amount added is less than 0.02 g / m ² , the scratch resistance may not be sufficiently exhibited. Conversely, if it exceeds 0.2 g / m ² , the ink absorbability may be deteriorated. In addition, when mix | blending a silicone oil with a coating liquid, it is preferable to use with the form of an emulsion.

(Other additives)
For the ink fixing layer, a dispersant, a thickener (flow modifier), an antifoaming agent, a water-proofing agent (printability improver), an antistatic agent, an antiseptic, an ultraviolet absorber, and a storage stability improver as necessary. Various additives such as a colorant, a fluorescent brightening agent, and a coloring agent can be appropriately added. Further, in order to further improve the ink fixing property and improve the water resistance, a single cationic compound may be blended.

The dry solid coating amount of the ink-fixing layer, but is not limited, it is preferable that generally is 2~100g / ^{m 2,} and more preferably 5 to 50 g / ^{m 2.} When the coating amount is 2 g / m ² or more, the ink absorbency in a high-definition and high-speed printer is sufficient, and when the coating amount is 50 g / m ² or less, the coating film is less likely to crack. Become.

  Two or more ink fixing layers can be formed. When the ink fixing layer is formed of two or more layers as described above, the silica and the adhesive constituting each layer may be the same or different. In addition, two or more types of silica and adhesive may be mixed in the same layer, or a combination thereof may be used. Examples of the coating apparatus for forming the ink fixing 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 curtain coater, and a die coater. A pre-weighing type die coater or the like is preferable because there is no coating liquid to be weighed and returned on the surface of the paper, so that it is not necessary to worry about inadvertent thickening due to mixing with the first coating layer.

  Further, the coated ink fixing layer may be subjected to a smoothing process such as super calendering or brushing as necessary. It can also be cast.

(Inkjet recording body production method)
The method for producing the ink jet recording material of the present invention is not particularly limited, but the following methods (A) to (D) are particularly preferable.
(A) On the support, a liquid containing borax as a crosslinking agent is applied as a first coating layer, on which a fine pigment, a polyvinyl alcohol-based resin, and a cationic ink fixing agent are included; A coating liquid containing acrylic resin or silicone oil is applied as the second coating layer, and borax contained in the first coating layer is infiltrated into the second coating layer to obtain a polyvinyl alcohol resin. A method for producing an ink jet recording material, wherein the ink fixing layer is formed by crosslinking.
(B) A liquid containing borax as a cross-linking agent is applied as a first coating layer on a support, and a coating liquid containing a fine pigment, a polyvinyl alcohol-based resin and a cationic ink fixing agent is formed thereon. Coating as the second coating layer, allowing the borax contained in the first coating layer to penetrate into the second coating layer to crosslink the polyvinyl alcohol resin, and then silicone acrylic resin or silicone oil A method for producing an ink jet recording material, wherein an ink fixing layer is formed by coating and impregnating a coating solution containing an ink.

In the above methods (A) and (B), boric acid is not added to the ink fixing layer coating solution, and a boron compound that becomes borate ions such as borax is added as a cross-linking agent to the first coating layer. In addition, the ink fixing layer is formed by gelling the second coating layer coating liquid to be coated thereon. In the case of this method, borate ions are diffused from the first coating layer into the coated coating liquid layer for the second coating layer, and sequentially crosslinked from the contact surface with the first coating layer. Begins and eventually the entire second coating layer crosslinks and gels. When drying is performed in a gelled state, cracks in the drying process can be prevented, so that an ink fixing layer without cracks can be formed.
The method (A) is a method in which a silicone acrylic resin or silicone oil is blended in the second coating liquid, and the silicone fixing resin or silicone oil is contained in the ink fixing layer, and the method (B) In the method, after the ink fixing layer is formed, the surface of the ink fixing layer is coated / impregnated with a coating liquid containing a silicone acrylic resin or silicone oil, so that the ink fixing layer contains the silicone acrylic resin or silicone oil. It is.
Both methods can provide an ink jet recording material having excellent recording properties for both the dye ink and the pigment ink, and excellent scratch resistance of the pigment ink.

However, in the above methods (A) and (B), when borate ions diffuse to the extent that the surface does not crack in the drying step, the portion below the surface (portion close to the first coating layer) Then, borate ions must be excessive. If borate ions are excessive, the number of cross-linking points is also excessive, and the ink fixing layer tends to be harder and more brittle than necessary. For example, in a printer that is compactly designed, fed from the front, reversed inside, and ejected from the front (also referred to as C-type feeding), in the case of a hard ink fixing layer, the ink fixing layer May crack.
For example, borate ions can be supplied from the surface of the ink fixing layer. However, in this method, it is necessary to apply a coating solution containing borate ions while the ink fixing layer coating solution has fluidity. Therefore, a coating apparatus capable of simultaneous multilayer coating is required. Further, in order to prevent the ink fixing layer coating liquid layer and the coating liquid layer supplying borate ions from being mixed inadvertently, it is necessary to pay attention to the physical properties of each coating liquid.

In the case of a composition that causes cracks during recording, it is preferable to employ the following method.
(C) On the support, a liquid containing an alkaline substance is applied as a first coating layer, on which fine pigment, polyvinyl alcohol-based resin, boric acid and a cationic ink fixing agent as a crosslinking agent are included, Further, a coating liquid containing a silicone acrylic resin or silicone oil is applied as a second coating layer, and an alkaline substance contained in the first coating layer is infiltrated into the second coating layer, thereby boric acid. And a polyvinyl alcohol resin is crosslinked to form an ink fixing layer.
(D) A liquid containing an alkaline substance is applied as a first coating layer on a support, and a fine pigment, a polyvinyl alcohol resin, and a coating containing boric acid and a cationic ink fixing agent as a cross-linking agent. The liquid is applied as a second coating layer, an alkaline substance contained in the first coating layer is permeated into the second coating layer to activate boric acid, and the polyvinyl alcohol resin is crosslinked, A method for producing an ink jet recording material, comprising forming an ink fixing layer by coating and impregnating a coating liquid containing a silicone acrylic resin or silicone oil.

In the methods (C) and (D), an alkaline substance is blended in the first coating layer. Examples of alkaline substances include sodium hydroxide, sodium carbonate, sodium hydrogen carbonate, sodium phosphate, potassium hydroxide, potassium carbonate, calcium hydroxide, and other alkali metal and alkaline earth metal salts, ammonia, diethylamine, triethylamine, and other ethylamines. And ethanolamines such as monoethanolamine, diethanolamine, and triethanolamine. All of these have an effect of activating an inactive crosslinking agent, but ethanolamines are most preferable from the viewpoints of storage stability and safety.
These alkaline substances have an action of dissolving and penetrating into the second coating layer coating liquid when the second coating layer coating liquid is applied.
On the other hand, the second coating layer coating solution contains a polyvinyl alcohol-based resin as an adhesive and boric acid as a crosslinking agent. In the state of the coating liquid, boric acid is in an inactive state, and crosslinking or gelation does not proceed. When the coating liquid for the second coating layer is applied on the first coating layer, it is activated as a crosslinking agent by the permeated alkaline substance, and crosslinking and gelation proceed, and the coating layer is dried. Thus, an ink fixing layer free from cracks can be formed.

  In this method, since the amount of the crosslinking agent can be adjusted before coating, it does not become harder and more brittle than required by the ink fixing layer due to an excessive crosslinking point, and the first coating layer coating solution and the second coating layer are not brittle. Since the coating layer coating liquid may be applied independently, since it can be easily applied with a publicly known public coating apparatus without paying more attention to the physical properties of each coating liquid, It is highly productive and economical. In addition, the first coating layer has functions such as blending pigments and adhesives to smooth the support and to adjust the speed and amount of the solvent in the ink that permeates the support. It can also be granted. Further, the hue of the recording medium can be adjusted by blending a fluorescent dye or a colorant.

The method (C) is a method in which a silicone acrylic resin or silicone oil is blended in the second coating liquid, and the silicone fixing resin or silicone oil is contained in the ink fixing layer. In the method, after the ink fixing layer is formed, the surface of the ink fixing layer is coated / impregnated with a coating liquid containing a silicone acrylic resin or silicone oil, so that the ink fixing layer contains the silicone acrylic resin or silicone oil. It is.
Both methods can provide an ink jet recording material having excellent recording properties for both dye ink and pigment ink, excellent scratch resistance of the pigment ink, and further improved cracking of the coating layer during paper feeding. it can.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.
Further, “parts” and “%” in the following examples and comparative examples represent “parts by mass” and “% by mass” of solids excluding water, respectively, unless otherwise specified.

<Example 1>
[Paper base]
100 parts by weight of wood pulp (LBKP; freeness 400 ml CSF), 5 parts by weight of calcined kaolin (trade name: Ancilex), 0.05 parts by weight of a commercially available sizing agent, 1.5 parts by weight of a sulfuric acid band, 0. A paper base material consisting of 5 parts by mass and 0.75 parts by mass of starch was used, and a paper substrate having a basis weight of 180 g / m ² was produced by a long net paper machine.

[Preparation of coating liquid A for first coating layer]
100 parts of diethanolamine (made by Kishida Chemical Co., Ltd., reagent) in water, 0.2 parts of wetting agent (made by Lion Co., Ltd., trade name: Leox 2160C), defoamer (made by San Nopco Co., Ltd., trade name) : 0.05 parts of Nopco 1407K) was added and dispersed to prepare a first coating layer coating solution A having a solid content concentration of 5%.

[Cationic silica fine particles]
Gas phase method silica having an average particle size of 1.0 μm (manufactured by Nippon Aerosil Co., Ltd., trade name: Aerosil A300, average primary particle size of about 8 nm) is dispersed by a homomixer and then flowed at high speed until the average particle size reaches 50 nm. The mixture was pulverized and dispersed with a collision type homogenizer to prepare an aqueous dispersion of 10% by mass silica.
10 parts by mass of a cationic compound having a 5-membered ring amidine structure (product name: Himax SC700M, molecular weight 300,000) having a 5-membered ring amidine structure was added to 100 parts by mass of the 10% by mass aqueous dispersion, and high-speed flow collision A 10% by mass aqueous dispersion of silica-cationic compound having an average particle size of 0.10 μm was further dispersed with a type homogenizer.

[Preparation of coating liquid A for second coating layer]
100 parts of cationic silica fine particles, 1.5 parts of boric acid (manufactured by Kishida Chemical Co., Ltd., reagent) and PVA as an adhesive (manufactured by Kuraray Co., Ltd., trade name: PVA-145, polymerization degree 4500, saponification) Degree 99%) 20 parts, wetting material (trade name: Emulgen 709) 0.5 parts, a silicone acrylic resin (manufactured by Shin-Nakamura Chemical Co., Ltd.) as a pigment ink scratch resistance improver, Product name: NK Polymer DK-9000) 0.6 parts, and antifoaming agent (manufactured by San Nopco Co., Ltd., trade name: SN deformer 777) 0.1 parts are mixed and stirred. Second coating layer coating solution A was prepared.

[Preparation of inkjet recording material]
After coating and drying the first coating layer coating liquid A on one side of the produced paper substrate so that the coating amount after drying is 1 g / m ² , the second coating is performed. The layer coating liquid A was applied and dried so that the coating amount after drying was 10 g / m ² to form an ink fixing layer, whereby an ink jet recording material was obtained. The amount of silicone acrylic resin contained in this ink jet recording material was 0.05 g / m ² .

<Example 2>
In Example 1, an ink fixing layer was formed in the same manner as in Example 1 except that the addition amount of the silicone acrylic resin in the preparation of the coating liquid A for the second coating layer was changed to 3.1 parts. A record was obtained. The amount of silicone acrylic resin contained in the ink jet recording material was 0.25 g / m ² .

<Example 3>
In Example 1, an ink fixing layer was formed in the same manner as in Example 1 except that the addition amount of the silicone acrylic resin in the preparation of the coating liquid A for the second coating layer was changed to 6.1 parts. A record was obtained. The amount of silicone acrylic resin contained in this ink jet recording material was 0.5 g / m ² .

<Example 4>
In Example 1, the silicone acrylic resin for preparation of the second coating layer coating solution A was a silicone oil emulsion (trade name: SM490EX, manufactured by Toray Dow Corning Co., Ltd.), and the addition amount was changed by 0.25 parts. Except that, an ink fixing layer was formed in the same manner as in Example 1 to obtain an ink jet recording material. The amount of silicone oil contained in this ink jet recording material was 0.02 g / m ² .

<Example 5>
In Example 4, an ink fixing layer was formed in the same manner as in Example 4 except that the amount of the silicone oil emulsion added in the preparation of the coating liquid A for the second coating layer was changed to 1.2 parts. Got the body. The amount of silicone oil contained in this ink jet recording material was 0.1 g / m ² .

<Example 6>
In Example 4, an ink fixing layer was formed in the same manner as in Example 4 except that the amount of the silicone oil emulsion added in the preparation of the coating liquid A for the second coating layer was changed to 2.5 parts. Got the body. The amount of silicone oil contained in this ink jet recording material was 0.2 g / m ² .

<Example 7>
[Preparation of coating liquid B for second coating layer]
100 parts of cationic silica fine particles, 1.5 parts of boric acid (manufactured by Kishida Chemical Co., Ltd., reagent) and PVA as an adhesive (manufactured by Kuraray Co., Ltd., trade name: PVA-145, polymerization degree 4500, saponification) Degree 99%) 20 parts, wetting material (Kao Co., Ltd., trade name: Emulgen 709) 0.5 parts, antifoaming agent (San Nopco Co., trade name: SN deformer 777) 0.1 The parts were mixed and stirred to prepare a second coating layer coating solution B having a solid content concentration of 12%.
[Preparation of third coating layer coating solution A]
A 3% diluted solution of a silicone acrylic resin (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name: NK Polymer DK-9000) was prepared as a pigment ink scratch resistance improver, and a third coating layer coating solution A was prepared. Was prepared.

[Preparation of inkjet recording material]
After coating and drying the first coating layer coating liquid A on one side of the produced paper substrate so that the coating amount after drying is 1 g / m ² , the second coating is performed. Coating and drying layer coating liquid B so that the coating amount after drying is 10 g / m ^2, and then coating and impregnating third coating layer coating liquid A with a # 4 Mayer bar And dried to form an ink fixing layer to obtain an ink jet recording material. The amount of silicone acrylic resin contained in the ink jet recording material was 0.24 g / m ² .

<Example 8>
[Preparation of coating liquid B for first coating layer]
100 parts of borax (manufactured by Shionogi Pharmaceutical Co., Ltd., trade name: borax) and 0.05 part of a wetting agent (product of Lion Corporation, trade name: Leox 2160C) are mixed and stirred in water, and the solid content concentration is 4%. A first coating layer coating solution B was prepared.
[Change of coating liquid C for second coating layer]
100 parts of cationic silica fine particles, 20 parts of PVA (manufactured by Kuraray Co., Ltd., trade name: PVA-145, polymerization degree 4500, saponification degree 99%) as an adhesive, wetting material (manufactured by Kao Corporation, product) Name: Emulgen 709), 0.5 parts of a silicone ink (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name: NK Polymer DK-9000) as an anti-scratch improver for pigment ink, antifoaming agent 0.1 part of (San Nopco Co., Ltd., trade name: SN deformer 777) was mixed and stirred to prepare a second coating layer coating solution C having a solid content concentration of 12%.

[Preparation of inkjet recording material]
After coating and drying the first coating layer coating liquid B on one side of the produced paper substrate so that the coating amount after drying is 1 g / m ² , the second coating is performed. The layer coating liquid C was applied and dried so that the coating amount after drying was 10 g / m ² to form an ink fixing layer, whereby an ink jet recording material was obtained. The amount of silicone acrylic resin contained in the ink jet recording material was 0.25 g / m ² .

<Example 9>
[Change of coating liquid D for second coating layer]
100 parts of cationic silica fine particles, 20 parts of PVA (manufactured by Kuraray Co., Ltd., trade name: PVA-145, polymerization degree 4500, saponification degree 99%) as an adhesive, wetting material (manufactured by Kao Corporation, product) Name: Emulgen 709) 0.5 parts and antifoaming agent (San Nopco Co., Ltd., trade name: SN deformer 777) 0.1 parts are mixed and stirred, the second coating with a solid content concentration of 12% Layer coating solution D was prepared.
[Preparation of third coating layer coating solution B]
A 3% diluted solution of a silicone acrylic resin (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name: NK Polymer DK-9000) was prepared as a pigment ink scratch resistance improver, and a third coating layer coating solution B was prepared. Was prepared.

[Preparation of inkjet recording material]
After coating and drying the first coating layer coating liquid B on one side of the produced paper substrate so that the coating amount after drying is 1 g / m ² , the second coating is performed. Coating and drying layer coating solution D so that the coating amount after drying is 10 g / m ² , then coating and impregnating third coating layer coating solution B with a # 4 Mayer bar And dried to form an ink fixing layer to obtain an ink jet recording material. The amount of silicone acrylic resin contained in the ink jet recording material was 0.24 g / m ² .

<Comparative Example 1>
In Example 1, an ink fixing layer was formed in the same manner as in Example 1 except that the addition amount of the silicone acrylic resin in the preparation of the second coating layer coating liquid A was changed from 0.6 part to 0 part. As a result, an ink jet recording material was obtained.

<Comparative example 2>
In Example 2, except that the amount of boric acid added in the preparation of the coating liquid A for the second coating layer was changed from 1.5 parts to 0 part, the same as in Example 2 for the second coating layer A coating solution was prepared, and an ink fixing layer was formed in the same manner as in Example 2 to obtain an ink jet recording material.

<Example 10>
An ink jet recording material (for postcard) was obtained in the same manner as in Example 1 except that the following paper base material (postcard base material) was used.

(Waste paper pulp A)
Kent waste paper (ash content: 33.2%) is disaggregated with a pulper, passed through a dust remover (cleaner and screen), then concentrated to a solids concentration of about 30% with a tilt extractor and screw press dehydrator. Disperse with a disperser while adding sulfonamidine (FAS) and bleaching, and after passing through a pulp washer (DNT washer: Aikawa Tekko) while diluting with water, adjust the freeness to 300 ml. Waste paper pulp A was obtained. The ash content of this pulp was 11.8%, and the fine fibers of 0.1 mm or less were 14.5%.

(Waste paper pulp B)
Magazine paper (ash content 20.3%) was disaggregated with a pulper, passed through a dust remover (cleaner and screen), freeness was adjusted to 350 ml with a double disk refiner, and used paper pulp B was obtained. The ash content of this pulp was 18.8%, and the fine fibers of 0.1 mm or less were 9.8%.

(Creation of paper substrate (postcard substrate))
A paper base material (postcard base material) was prepared by laminating five layers by the following manual paper making method.
"Prescription of surface and back layers"
Pulp formulation: 100% hardwood bleached kraft pulp (LBKP).
Sizing agent: Add rosin emulsion sizing agent in solid form and 1.5% of pulp.
Paper strength enhancer: Polyacrylamide is added in the form of 2.0% pulp.
Yield improver: High molecular weight polyacrylamide is added and 0.8% of pulp is added.
Sulfuric acid band: 8% aqueous solution as Al2O3 and 2.5% added to pulp.

"Prescription under the front and bottom"
Pulp formulation: 100% recycled paper pulp A.
Sizing agent: Add rosin emulsion sizing agent in solid form and 1.5% of pulp.
Paper strength enhancer: Polyacrylamide is added in the form of 2.0% pulp.
Yield improver: High molecular weight polyacrylamide is added and 0.8% of pulp is added.
Sulfuric acid band: 8% aqueous solution as Al2O3 and 2.5% added to pulp.

"Medium-level prescription"
Pulp formulation: 100% recycled paper pulp B
Paper strength enhancer: Polyacrylamide is added in the form of 2.0% pulp.
Sulfuric acid band: 8% aqueous solution as Al2O3 and 2.5% added to pulp.

Surface in a square sheet machine of 150 mesh wire of the formulated layers of material as described above, the backing layer is a target basis weight of 35 g / m ^2, handsheet front lower, lower back, middle layer to target basis weight of 40 g / m ² I did. The wet paper was layered between the surface layer, the lower layer, the middle layer, the lower layer, and the back layer by coating 0.3 g / m ^{2 of} an aqueous solution of 2.5% oxidized starch at an absolute dry solid content of 105 ° C. A hand-dried paper was obtained by drying with a drum dryer for 3 minutes.

Next, a mixed aqueous solution of 2.5% oxidized starch, 1.1% polyvinyl alcohol, and 0.4% olefin-based surface sizing agent was prepared as a sizing solution for the front and back sizing paper. This front / back surface size solution is applied to the surface (offset surface) with a Meyer bar at a dry dry solid content of 2 g / m ² , and the back surface is coated with ² g / m ² and then air-dried and smoothed with a small calender. Got.

<Comparative Example 3>
In Example 10, the ink fixing layer was formed in the same manner as in Example 1 except that the addition amount of the silicone acrylic resin in the preparation of the second coating layer coating liquid A was changed from 0.6 part to 0 part. As a result, an ink jet recording material was obtained.

<Evaluation method>
Evaluation of cracks in the coating layer of ink jet recording media, ink absorbency, ink scratch resistance, sharpness of recorded images, and cracking of the coating layer during paper feeding using the following methods Are shown in Table 1.

"Coating layer cracks"
The surface of the coating layer of the ink jet recording material was observed with an optical microscope (magnification: x100), and the presence or absence of cracks was observed.
5: No cracks are observed on the surface of the coating layer.
4: Slight cracks are observed on the surface of the coating layer.
3: Some cracks are observed on the surface of the coating layer.
2: Cracks are observed in a considerable portion of the coating layer surface.
1: Cracks are observed on almost the entire surface of the coating layer.

"Absorbability of pigment ink"
The ink-jet recording medium is printed with a solid and green band of 200% mixed color so that the boundary is in contact, and the mixed state of green and red at the boundary is observed with an optical microscope (magnification: × 50) and visually. It was evaluated in five stages.
Note that a printer using a pigment-based ink (trademark: PX-G920, printing mode: EPSON photographic paper, recommended mode) was used.
5: No mixed color of green and red is observed even by observation with an optical microscope.
4: Although not visually recognized at all, a slight color mixture is observed with an optical microscope.
3: Although slight color mixing is recognized visually, there is no practical problem.
2: Color mixing is recognized visually and there is a problem depending on the design.
1: There are many color mixtures and it cannot endure practical use.

"Scratch resistance of pigment ink"
The ink jet recording medium was solidly printed with black ink, allowed to stand overnight and dried, then set on a Gakushin dyeing fastness tester, and the printed portion was rubbed with black Rash paper to test the scratch resistance of the pigment ink. The degree of black ink peeling was visually observed and evaluated in five stages of writing. The printer was manufactured by EPSON (trade name: PX-G920, print mode: EPSON photographic paper, recommended mode), the load applied to the Gakushoku dyeing fastness tester was 1,900 g, and the number of rubbing was one.
5: No peeling of black ink is observed.
4: It is recognized that the black ink is slightly peeled off.
3: Black ink is peeled off a little, but there is no practical problem.
2: Peeling of black ink is recognized, and there is a problem depending on the design.
1: Black ink is peeled off and cannot be used practically.

“Clarity of recorded image (print density)”
The ink jet recording medium was solid-printed with black ink, and the color density was measured with a Macbeth reflection densitometer (model: Gretag Macbeth RD-19, manufactured by Macbeth).
For inkjet printers, CANON (trade name: iP-4300, print mode: high-quality exclusive paper, clean mode) is used as a printer that uses dye-based ink, and EPSON is used as a printer that uses pigment-based ink. (Product name: PX-G920, print mode: EPSON photographic paper, recommended mode) was used.

"Coating layer cracks when feeding paper"
Recording is performed by a paper feeding method (C-type paper feeding) in which an ink jet recording body is set in a paper feeding tray below the printer iP4300 with a printing surface facing downward, and the recording body is rotated inside the printer so that the printing surface faces upward. After printing with solid black on the entire surface of the body, the surface of the printed part was visually observed for scratches.
5: No cracks in the coating layer are observed.
4: Although there are some cracks, there is no practical problem.
3: Although the crack is somewhat conspicuous, there is no practical problem.
2: There are many cracks and a practically problematic level.
1: There are so many cracks that it cannot withstand practical use.

  As is apparent from Table 1, the ink jet recording material of the present invention not only exhibits excellent ink absorbency, scratch resistance and high recording density in printers using pigment-based inks, but also in printers using dye-based inks. In addition, the recording density was high, and the surface of the coating layer was not easily broken even when the printer was fed. On the other hand, it was found that the comparative example was evaluated as a practically problematic level for any of the evaluation items.

  The present invention can be used as an ink jet recording material for dye ink and an ink jet recording material for pigment ink because both the dye ink and the pigment ink are excellent in recordability and excellent in scratch resistance of the pigment ink. Moreover, since it can be used without minding whether the ink of an inkjet printer is a dye ink or a pigment ink at the time of printing out, it can be used as an ink jet recording medium combined with dye ink and pigment ink. Furthermore, since this ink jet recording material is excellent in scratch resistance of pigment ink even when used for postcard applications, the movable part of the apparatus and other postal items in the process of collection and distribution, sorting, postmarking, etc. Even if they rub against each other, they can withstand enough.

Claims (7)

In an ink jet recording medium having an ink fixing layer provided on a support, the ink fixing layer is a fine pigment, an adhesive for fixing the fine pigment to the support, and a part of the adhesive is crosslinked to form an ink fixing layer. An ink jet recording material comprising a crosslinking agent and a cationic ink fixing agent for suppressing cracking, and further containing a silicone acrylic resin or silicone oil. 2. The ink jet recording material according to claim 1, wherein the adhesive contained in the ink fixing layer is a polyvinyl alcohol resin, and the crosslinking agent is a boron compound. Use as a postcard of the ink jet recording material according to claim 1 or 2. On the support, a liquid containing borax as a crosslinking agent is applied as a first coating layer, on which a fine pigment, a polyvinyl alcohol-based resin and a cationic ink fixing agent are included, and further, a silicone acrylic resin Alternatively, a coating liquid containing silicone oil is applied as the second coating layer, and borax contained in the first coating layer is allowed to penetrate into the second coating layer to crosslink the polyvinyl alcohol resin. A method for producing an ink jet recording material, comprising forming an ink fixing layer. On the support, a liquid containing borax as a crosslinking agent is applied as a first coating layer, and a coating liquid containing a fine pigment, a polyvinyl alcohol-based resin and a cationic ink fixing agent is applied on the second coating layer. Coated as a coating layer, borax contained in the first coating layer is permeated into the second coating layer to crosslink the polyvinyl alcohol resin, and then contains a silicone acrylic resin or silicone oil A method for producing an ink jet recording material, comprising forming an ink fixing layer by coating and impregnating a coating liquid. On the support, a liquid containing an alkaline substance is applied as a first coating layer, and further contains a fine pigment, a polyvinyl alcohol resin, boric acid and a cationic ink fixing agent as a crosslinking agent, and silicone. A coating liquid containing acrylic resin or silicone oil is applied as the second coating layer, and an alkaline substance contained in the first coating layer is infiltrated into the second coating layer to activate boric acid. A method for producing an ink jet recording material, comprising forming an ink fixing layer by crosslinking a polyvinyl alcohol resin. A liquid containing an alkaline substance is applied as a first coating layer on a support, and a coating liquid containing fine pigment, polyvinyl alcohol resin, boric acid and a cationic ink fixing agent as a cross-linking agent is applied thereon. Coating as the second coating layer, infiltrating the alkaline material contained in the first coating layer into the second coating layer to activate boric acid, cross-linking the polyvinyl alcohol resin, then silicone acrylic A method for producing an ink jet recording material, comprising forming an ink fixing layer by coating and impregnating a coating solution containing a resin or silicone oil.