JP2012200891A - Manufacturing method of glossy ink-jet recording paper - Google Patents

Abstract

The present invention provides a glossy inkjet recording paper that has excellent ink jet recording aptitude such as recording density, excellent glossy appearance, conveyance scratch resistance when feeding a printer, and excellent productivity.
A pretreatment step in which an alkaline solution is applied in advance on a paper support or at least one undercoat layer formed on the support, silane coupling containing an amino group or a quaternary ammonium group A step of forming an ink fixing layer in which an amorphous silica treated with an agent, a polyvinyl alcohol resin, and a coating liquid for forming an ink fixing layer containing boric acid are formed, and a coating liquid containing anionic colloidal silica And a step of forming a gloss-developing layer that is cast-finished after coating.
[Selection figure] None

Description

  TECHNICAL FIELD The present invention relates to glossy inkjet recording paper, and in particular, glossy inkjet recording having excellent productivity for inkjet recording such as recording density, excellent glossy appearance, transport scratch resistance when feeding a printer, and excellent productivity. The present invention relates to a paper manufacturing method.

The ink jet recording system that forms an image by attaching ink droplets ejected from fine nozzles onto the surface of the recording paper has low noise during recording, enables high-speed recording, and forms a full-color image. There are advantages that it is easy and the recording cost is low compared to other printing methods. For this reason, it is widely used in terminal printers, facsimiles, plotters, form printing, and the like.
In recent years, due to improvements in high-definition and high-speed ink-jet printers, it has been spreading to general household users for the purpose of outputting photographic images using a digital camera or the like. Inkjet recording paper has excellent surface gloss and appearance, color clarity, color depth (depth), and fineness so that the quality of inkjet recording paper that outputs photographic images is close to that of silver salt photographs. High image quality is required.

  The method for giving gloss to the surface of inkjet recording paper is the same as the method for giving gloss to printing pigment-coated paper, and a calendar that smoothes the surface with a super calender or gloss calendar after the coated paint has dried. There are known finishing methods and casting methods that produce gloss by pressing and drying the heated cast drum while the coated surface is in a wet or rewet state. It is suitable as a method for forming a beautiful surface.

In order to impart color developability and depth to the recorded image, it is preferable to make the ink fixing layer and the gloss developing layer transparent. In the ink fixing layer, a cationic resin is generally used as a dye fixing agent. However, when a cationic resin having a low molecular weight is used to increase the transparency of the ink fixing layer, there is a problem that printing water resistance is poor. . On the other hand, when a cationic resin having a large molecular weight is used, there is a problem that the transparency of the ink fixing layer is lowered.
Since many materials that are widely used in cast finish paints are anionic and stable, the gloss developing layer is generally anionic. When a cationic resin is used for the fixing layer, since the binding force between the inorganic component of the silica and the organic component of the cationic resin is weak, the glossy expressing layer in which the cationic resin is anionic due to continuous production. And the transparency of the glossy layer is impaired.

  Further, in the cast finishing, the performance of stably peeling the recording paper from the coating / drying apparatus such as a cast drum, that is, the release property is an important performance. If the recording paper does not release smoothly and a part of the coating layer is deposited on a coating device such as a cast drum and the cast drum is contaminated, continuous cast finishing cannot be performed. In this case, there is a problem in that productivity is remarkably lowered because it is necessary to temporarily suspend coating and remove dirt from the coating apparatus. On the other hand, if the releasability is poor, it becomes difficult to peel the paper from the drum surface, and if it is severe, the paper may be torn and operation may not be possible. Therefore, it is an important issue to realize excellent releasability in the glossy layer that is cast-finished.

  Another important issue apart from releasability is drum haze. When recording paper is continuously produced using a cast drum, dirt may gradually adhere to the surface of the cast drum, and the drum surface may become cloudy. If the drum is cloudy, the surface of the paper cannot be copied onto a clean cast drum surface, and the glossiness of the paper surface becomes unstable and the glossiness is lowered. Resolving mold releasability and drum haze is not always compatible, but is a different issue. That is, even if the drum haze is good, if the releasability is inferior, the paper will not peel off from the cast drum, and if it is severe, the paper will be torn and cannot be operated. The glossiness of the paper may decrease and the appearance may deteriorate. Therefore, it is important to satisfy both releasability and drum haze. Various materials called mold release agents are used to improve mold release properties and drum haze. When the cast paint is anionic, such as cast coated paper for printing, the range of materials that can be used is wide, and these problems have been solved by appropriately combining known and publicly used materials. In some cases, the materials that can be used are limited, and it is difficult to solve the problem by the effect of the release agent alone.

On the other hand, with the spread of inkjet printers to general household users, improvement in printer installation efficiency is required. As one of the solutions to reduce the installation area, place the recording paper face down on the paper feed tray at the bottom of the printer, reverse the recording paper picked up from the back inside the printer, and feed the recording face upward A paper feeding method for printing is adopted. This paper feeding method is sometimes referred to as a C-type paper feeding method or the like, in which the state that the recording paper is reversed inside the printer is compared to the letter “C” of the alphabet. In contrast, a conventional paper feeding method from the back of the printer is called a J-type paper feeding method and the like, and is distinguished.
In a C-type paper feed type printer, it is necessary to reverse the recording paper within a narrow paper feed path inside the printer, and the ink jet recording paper is likely to be cracked on the recording surface during this reversal. In particular, in the case of inkjet recording paper having gloss, such a conveyance flaw (breaking) is likely to occur and is conspicuous, which is a problem.

  In Patent Literature 1, an amorphous silica, a binder, an ink fixing layer having a binder and a crosslinking agent for the binder, and a cationic property on a paper support or at least one undercoat layer formed on the support. Glossy ink jet recording paper mainly composed of modified colloidal silica and provided with a glossy expression layer that is cast finished is described. However, this glossy ink jet recording material is susceptible to drum fogging and has poor release properties, and recording paper could not be produced stably. Further, when recording was performed with a C-type paper feeding type printer, the conveyance flaw was conspicuous.

JP, 2006-142748, A Claim 1, 3, 4

  An object of the present invention is to enable clear image printing, to have excellent blank paper glossiness, and to have excellent recording suitability to be hardly damaged even when fed to a printer. It is an object of the present invention to provide a method for producing a glossy ink jet recording paper which has good properties, does not cause drum fogging, and has excellent productivity.

As a result of intensive studies to solve the above problems, the inventors of the present invention applied an alkaline solution in advance before forming the ink fixing layer on an ink jet recording paper having a layer structure having an ink fixing layer and a glossy expression layer. The ink fixing layer is formed using an amorphous silica treated with a silane coupling agent containing an amino group or a quaternary ammonium group, a polyvinyl alcohol resin, and a coating solution containing boric acid. The present inventors have found that this can be achieved by using anionic colloidal silica without using cationic colloidal silica for the glossy layer, and have completed the present invention. That is, the present invention
(1) On the air-permeable substrate or on at least one undercoat layer formed on the air-permeable substrate,
A pretreatment step in which an alkaline solution is applied in advance;
An ink fixing layer forming step of coating an amorphous silica treated with a silane coupling agent containing an amino group or a quaternary ammonium group, a polyvinyl alcohol-based resin, and an ink fixing layer forming coating solution containing boric acid; and ,
After applying a coating solution containing an anionic colloidal silica, a gloss developing layer forming step of casting finish,
A method for producing a glossy ink jet recording paper having:
(2) The method for producing a glossy ink jet recording paper according to (1), wherein the silane coupling agent is an ethoxysilane compound having an amino group.
(3) The method for producing a glossy ink jet recording paper as described in (1) or (2), wherein the amorphous silica is vapor phase method silica.
(4) The method for producing a glossy ink jet recording paper according to any one of (1) to (3), wherein the alkaline solution contains ethanolamines and / or alkaline earth metal salts.

  According to the method for producing an inkjet recording paper of the present invention, it is glossy, can print a clear image, has a good white paper gloss, has transport scratch resistance when fed into a printer, and is manufactured. Even at times, it is possible to obtain an ink jet recording paper that has good releasability, does not cause drum fogging, and has excellent productivity.

<Base material>
The substrate used for the glossy inkjet recording paper of the present invention is not particularly limited as long as it is a gas permeable substrate. The air-permeable substrate can be used as long as the moisture in the glossy layer that is in a wet state can be evaporated from the back surface through the substrate at the time of cast finishing during production. For example, it is preferable to use a paper base material, a gas-permeable resin film, or a sheet material. Among them, it is preferable to use a paper base material from the viewpoints of excellent air permeability, ease of handling as a recording paper, and ease of disposal. As the paper substrate, a commonly used known paper substrate can be used as long as the effects of the present invention are not impaired. For example, fine paper, art paper, coated paper, cast coated paper, craft paper, Examples include baryta paper, paperboard, impregnated paper, and vapor-deposited paper.
In addition, as a standard of air permeability, Oken type air permeability (Japan TAPPI No. 5) is preferably 10 to 2000 seconds, and more preferably 10 to 1000 seconds. If the air permeability is less than 10 seconds, there is a possibility that the ink fixing layer coating solution may excessively permeate the air-permeable base material (for example, paper base material). In doing so, the operability may be reduced.

[Paper base]
The base paper that constitutes the paper base (if the paper base has a coating layer like art paper, the paper part that does not have a coating layer, and if the paper base does not have a coating layer, the paper The base material itself) is mainly composed of wood pulp, 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.

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 base paper, 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 discharged from the ink jet printer. Among them, light calcium carbonate is a base paper with high whiteness. Is obtained, and glossiness of the ink jet recording paper is also increased, which is preferable. As for the content rate (ash content) of the filler of a base paper, about 1-20 mass% is preferable. Within this range, smoothness, air permeability, paper strength, and rigidity are balanced, and a glossy inkjet recording paper excellent in balance of glossiness, image clarity, and rigidity is easily obtained.

  Examples of the auxiliary agent added to the base paper include a sizing agent, a fixing agent, a paper strength enhancing agent, a cationizing agent, a yield improving agent, 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. In addition, as a papermaking method, acidic papermaking or neutral papermaking, a long paper machine or a round paper machine, a single-layer papermaking or a multi-layer papermaking can be appropriately selected and manufactured.

  The base paper may be subjected to size press processing. 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 is preferable, and the sticky sizing degree (JIS-P8122) of the base paper 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 base paper is not specifically limited, About 20-400 g / m < ² > is preferable. Although the thickness of a base paper is not specifically limited, According to a use, it selects suitably in the range of 20 micrometers-500 micrometers.

(Undercoat layer)
The present invention relates to coating of at least two layers of a single ink fixing layer provided on a gas-permeable substrate and a gloss developing layer which is provided on the ink fixing layer and forms the outermost portion of the recording paper. Having a layer. The ink fixing layer is not limited to one layer, and two or more ink fixing layers may be provided as necessary. If necessary, an undercoat layer may be provided between the gas permeable substrate and the ink fixing layer.
The undercoat layer can be provided for the purpose of supplementing the function of the ink fixing layer. For example, by providing an undercoat layer for the purpose of absorbing the ink solvent, it is possible to quickly separate the colored component and the solvent component of the ink. For example, by providing an undercoat layer for the purpose of preventing the ink solvent from penetrating into the substrate, cockling due to the ink solvent penetrating into the paper substrate can be prevented. Of course, an undercoat layer that absorbs the ink solvent may be laminated on the undercoat layer that does not allow the ink solvent to penetrate into the substrate. Even in the state where the undercoat layer is provided, since it is necessary to have air permeability, the resin laminate layer and the like are excluded.

  Both undercoat layers are coating layers containing a pigment and an adhesive. Examples of pigments include kaolin (containing clay), mica, calcium carbonate, titanium oxide, zinc oxide, amorphous silica (containing colloidal silica), aluminum oxide, zeolite, sepiolite, smectite, synthetic smectite, magnesium silicate, magnesium carbonate, and 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. As the adhesive, a known adhesive for inkjet recording paper can be used, and a water-dispersed adhesive or a water-soluble adhesive can be used alone or in combination.

In the case of the undercoat layer for the purpose of absorbing the ink solvent, it is preferable to use amorphous silica, aluminum oxide, aluminosilicate, or calcium carbonate as the pigment, and it is particularly preferable to use wet method silica. Although it does not specifically limit about an adhesive agent, If it uses excessively, since the absorptivity of an ink solvent will be impaired, it is about 7-50 mass parts with respect to 100 mass parts of pigments.
On the other hand, in the case of an undercoat layer for the purpose of preventing the ink solvent from penetrating into the substrate, it is preferable to use mica, kaolin (containing clay), calcium carbonate, smectite, synthetic smectite, etc. as the pigment. ) Is preferably used. As the adhesive, it is preferable to use a water-dispersed adhesive because the effect of suppressing the penetration of the ink solvent is high, and is preferably about 50 to 500 parts by mass with respect to 100 parts by mass of the pigment.

Further, various auxiliary agents such as a dispersant, a thickener, an antifoaming agent, an antistatic agent, and an antiseptic used in the production of general coated paper are appropriately added to the undercoat layer. Further, a fluorescent dye and a colorant can be added to the undercoat layer. Further, a crosslinking agent can be blended in order to prevent cracking of the ink fixing layer.
Examples of the coating apparatus for forming the undercoat layer include various coating apparatuses such as 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.

<Pretreatment process>
The present invention provides a gas-permeable substrate or at least one subbing layer formed on the gas-permeable substrate.
It has the pre-processing process which coats an alkaline solution previously.
The alkaline solution to be applied has a pH at 25 ° C. of preferably 9.0 or more, and more preferably 10.0 or more. When the pH of the solution is 9.0 or more, the effect of suppressing cracking of the ink fixing layer is enhanced. In addition, although the upper limit of pH is not prescribed | regulated, it is preferable that pH is 13.0 or less since a solution can be adjusted easily.

Examples of the solvent for the alkaline solution include water or an aqueous solvent obtained by adding a small amount of an organic solvent to water. Examples of the organic solvent include alcohols such as methanol, ethanol and propanol, ketones such as acetone and methyl ethyl ketone, and ethers such as diethyl ether and ethylene glycol monotertiary butyl ether.
When the organic solvent is contained, the content is preferably 20% by mass or less, and more preferably 10% by mass or less. If content of an organic solvent is below the said upper limit, pH can be adjusted easily.

In order to make the pH of the alkaline solution 9.0 or higher, an alkaline substance may be added to the solvent. 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.
Among alkaline substances, ethanolamines and alkaline earth metal salts are preferred from the viewpoint of storage stability of white paper on inkjet recording paper. Especially, ethanolamines are more soluble in water than alkaline earth metal salts, so they are cracked. This is preferable because of its excellent effect of preventing the above.

The alkaline solution may contain a pigment and an adhesive. As the pigment and the adhesive, the same pigments and adhesives contained in the ink fixing layer can be used.
The content of the pigment in the alkaline solution is preferably 30% by mass or less, more preferably 10% by mass or less, and 0% by mass from the viewpoint of preventing the ink fixing layer from peeling (that is, the pigment is added). It is particularly preferred that it is not contained).
The content of the adhesive in the alkaline solution is preferably 30% by mass or less, more preferably 10% by mass or less, from the viewpoint of ease of movement of alkaline substances and hydroxide ions to the fixing layer. 0 mass% (that is, no adhesive is included) is particularly preferable.
In addition, you may mix | blend additives, such as a wetting agent, an antifoamer, a viscosity modifier, a fluorescent whitening agent, and a coloring agent, with an alkaline solution.

Examples of the coating apparatus for applying the alkaline solution include various coating apparatuses such as 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.
Dry the solid coating amount of the alkaline solution is preferably from 0.3 to 5 g / m ^2, and more preferably 0.5 to 3 g / m ^2. If the coating amount is equal to or greater than the lower limit value, cracking of the ink fixing layer can be further prevented, and if the coating amount is equal to or less than the upper limit value, a decrease in coating speed can be prevented.
The alkaline solution is preferably dried after coating. If the alkaline solution is dried, crosslinking of the polyvinyl alcohol can be easily advanced from the support side when the ink fixing layer forming coating solution is applied. The drying method after applying the alkaline solution is not particularly limited, and for example, heat drying with hot air, radiant heat drying by infrared irradiation (including near infrared rays and far infrared rays) and the like can be applied. Among them, the method of drying by radiant heat is preferable because a solution having a low viscosity can be dried uniformly.

  In particular, the alkaline substances preferably used in the present invention are ethanolamines as described above, but since ethanolamines are liquid at room temperature, the support used is an ink even after coating and drying an alkaline solution. Since it is a support in which the absorbability of the solvent is suppressed or a support that does not absorb the ink solvent, it remains on the support surface in a liquid state. Accordingly, when drying is performed by applying too strong hot air to the alkaline solution, ethanolamines appear to be undulated on the surface of the support and may not be uniformly coated. If the alkaline substance is non-uniform, cracks in the ink fixing layer provided on the alkaline substance may be non-uniform, and the appearance and printability may be non-uniform. Therefore, in the present invention, it is more preferable to use drying by radiant heat for drying the alkaline solution.

<Ink fixing layer forming step>
In the ink fixing layer forming step, amorphous silica treated with a silane coupling agent containing an amino group or a quaternary ammonium group on the pretreated air-permeable substrate or undercoat layer, and a polyvinyl alcohol resin Then, a coating liquid for forming an ink fixing layer containing boric acid is applied.

[Amorphous silica]
As pigments for the ink fixing layer, kaolin (containing clay), calcium carbonate, titanium oxide, zinc oxide, amorphous silica, colloidal silica, alumina, alumina hydrate, zeolite, sepiolite, smectite, synthetic smectite, magnesium silicate , Magnesium carbonate, magnesium oxide, diatomaceous earth, styrene plastic pigment, hydrotalcite, urea resin plastic pigment, benzoguanamine plastic pigment, etc., but in the present invention, amorphous silica excellent in recordability and glossiness Is used.
Examples of the amorphous silica include a gas phase method, a wet method (precipitation method, gel method), and mesoporous silica. Among them, it is preferable to use gas phase method silica. Vapor phase silica can be produced by distilling the purity of silicon tetrachloride as a raw material by distillation, and can be produced by combustion hydrolysis of silicon tetrachloride in the gas phase using a closed system. It is also possible to prevent contamination by impurities. For this reason, it is preferable to use in order to obtain the outstanding transparency compared with wet process silica etc. By using gas phase method silica having high purity for the ink fixing layer, the glossiness of the ink jet recording paper is improved, and when recording, a recorded image having a high print density can be obtained.
As the amorphous silica, those treated with a silane coupling agent containing an amino group or a quaternary ammonium group are used.

(Silane coupling agent)
The silane coupling agent is hydrolyzed by moisture to form silanol and partially condensed to an oligomer state. Subsequently, it adsorbs to the amorphous silica surface in a hydrogen bond, and then undergoes a dehydration condensation reaction by a drying process to form a strong chemical bond.
The silane coupling agent used in the present invention contains an amino group or a quaternary cation group. Thereby, since it has a function as an ink fixing agent and the amorphous silica is bonded by the silanol group of the silane coupling agent, it is easy to fix the ink and the ink jet recording suitability can be improved.
In addition, since the silane coupling agent has a strong chemical bond with the amorphous silica, it is difficult to elute into the glossy layer and can be stably produced continuously.

  Examples of the silane coupling agent include N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, N- (β-aminoethyl). ) -Γ-aminopropyltriethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-triethoxysilyl-N- (α, γ-dimethyl-butylidene) propylamine, N-phenyl- Examples include γ-aminopropyltrimethoxysilane, N- (vinylbenzyl) -β-aminoethyl-γ-aminopropyltriethoxysilane hydrochloride, octadecyldimethyl- (γ-trimethoxysilylpropyl) -ammonium chloride, and the like. Among them, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane and N- (β-aminoethyl) -γ-aminopropyltriethoxysilane are preferred because of their good reactivity with amorphous silica. , Γ-aminopropyltriethoxysilane, and γ-aminopropyltrimethoxysilane are preferably used. Particularly, an ethoxysilane compound having an amino group is preferable, and γ-aminopropyltriethoxysilane is particularly preferable because a clear image can be obtained. These silane coupling agents may be used alone or in combination of two or more.

About pH of the aqueous solution containing a silane coupling agent, pH is adjusted to less than 7, Preferably pH is adjusted to 5 or less, More preferably, pH is adjusted to 3 or less. Note that the lower limit of pH is substantially 0 or more. By adjusting the pH to less than 7, the cationicity of the silane coupling agent containing an amino group or a quaternary cation group is increased and the reactivity with amorphous silica is improved.
1-30 mass% is preferable and, as for the density | concentration of the silane coupling agent in aqueous solution, 5-20 mass% is more preferable. If it is less than 1% by mass, it is difficult to disperse the amorphous silica and it is difficult to obtain the ink fixing ability. If it exceeds 30% by mass, the silane coupling agent becomes excessive, which inhibits ink absorption and is disadvantageous in terms of cost.
Although the chemical | medical agent which adjusts pH is not specifically limited, Since it is advantageous in terms of cost, an inorganic acid is used preferably, and especially hydrochloric acid, nitric acid, and a sulfuric acid (usually 0.01-10N aqueous solution is used. ) Is more preferably used. Moreover, the chemical | medical agent which adjusts pH may use an organic acid from a viewpoint of corrosion prevention of a manufacturing facility, and especially an acetic acid and lactic acid are used preferably.

  Amorphous silica treated with a silane coupling agent containing an amino group or a quaternary ammonium group can use fine secondary particle pigments having an average particle diameter of about 10 nm to 1 μm, and fine secondary particle pigments of 10 nm to 800 nm. Preferably, fine secondary particle pigments of 10 nm to 500 nm are more preferably used. If the particle diameter is less than 10 nm, the ink absorbability may be lowered. If it exceeds 1 μm, the transparency of the ink fixing layer may be deteriorated, the print density may be significantly lowered, and the smoothness may be impaired. In order to obtain high glossiness, it is necessary to increase the coating amount of the upper glossy expression layer. As a result, there is a concern that ink absorbability is lowered and productivity is lowered.

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

  The ink fixing layer uses amorphous silica treated with a silane coupling agent containing an amino group or a quaternary ammonium group as a pigment, but other pigments are used in combination as long as the effects of the present invention are not impaired. can do.

[Polyvinyl alcohol resin]
The polyvinyl alcohol-based resin is used as a binder for adhering the amorphous silica to a gas permeable substrate or an undercoat layer.
Known binders for the ink fixing layer include water such as styrene-butadiene copolymer resin, conjugated diene resin of methyl methacrylate-butadiene copolymer, acrylic resin, and vinyl resin such as ethylene-vinyl acetate copolymer resin. Dispersion adhesives, proteins such as casein, soy protein, gelatin, synthetic protein, various starches such as starch and oxidized starch, various polysaccharides such as chitin and chitosan, polyvinyl alcohol, cationic polyvinyl alcohol, silyl-modified polyvinyl alcohol Water-soluble adhesives such as polyvinyl alcohols containing modified polyvinyl alcohol such as, cellulose derivatives such as carboxymethyl cellulose and methyl cellulose, aqueous polyurethane resins, aqueous polyester resins, etc. are known. From strength balance Use of a vinyl alcohol-based resin. In addition, another binder can also be used together in the range which does not inhibit the effect of this invention.

  The properties of the polyvinyl alcohol resin differ depending on the saponification degree, and it is preferable to select the saponification degree 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 ink fixing layer is increased, and foaming does not occur during the preparation of the coating liquid, and the workability during production is very good. It is. Further, when partially saponified polyvinyl alcohol having a saponification degree of 75 to 90% is used, the flexibility of the ink fixing layer is excellent and it is very effective in preventing the cracking. These polyvinyl alcohols having different saponification degrees may be used alone or in combination depending on the purpose.

  Moreover, it is preferable that the polymerization degree of the said polyvinyl alcohol-type resin is 3000 or more, and it is especially preferable that it is 3500-5000. If the degree of polymerization is less than 3000, the strength of the ink fixing layer is weak, cracks are likely to occur, and paper dust may be generated during cutting. If it exceeds 5000, sufficient ink absorbability is difficult to obtain. At the same time, the viscosity of the solution is high, and the handling surface in adjusting the coating liquid may be difficult.

  The blending amount of the binder containing the polyvinyl alcohol resin in the ink fixing layer is preferably 7 to 50 parts by mass, more preferably 10 to 40 parts by mass with respect to 100 parts by mass of the pigment containing amorphous silica. preferable. If the blending amount is less than 7 parts by mass, the coating film strength may not be sufficient, and if it exceeds 50 parts by mass, the ink absorbability may be impaired.

[Cationic resin]
In general, a cationic resin that has an action of fixing a dye pigment in an ink for ink jet recording in an ink jet recording paper and thereby can impart water resistance to a printed image is used.

Examples of the cationic resin include (a) polyalkylene polyamines such as polyethylene polyamine and polypropylene polyamine or derivatives thereof, (b) an acrylic polymer having a secondary or tertiary amino group or a quaternary ammonium group, Or acrylamide copolymers thereof, (c) polyvinylamines and polyvinylamidines, (d) dicyan-based cationic compounds represented by dicyandiamide-formalin copolymers, and (e) dicyandiamide-polyethyleneamine copolymers. Polyamine cationic compounds, (he) epichlorohydrin-dimethylamine copolymer, (to) diallyldimethylammonium-SO ₂ polycondensate, (thi) diallylamine salt-SO ₂ polycondensate, (li) diallyldimethylammonium Chloride polymer, ( ) Allylamine salt copolymer, (le) dialkylaminoethyl (meth) acrylate quaternary salt copolymer, (e) acrylamide-diallylamine copolymer, (wa) cationic resin having a 5-membered ring amidine structure, etc. Can be mentioned.

  In the present invention, since an amorphous silica treated with a silane coupling agent containing an amino group or a quaternary ammonium group is used as a pigment in the ink fixing layer, the use of a cationic resin is optional. In order to obtain a desired effect such as water resistance of the recorded matter, a cationic resin can be appropriately blended.

〔Boric acid〕
The ink fixing layer contains a crosslinking agent that suppresses cracking of the ink fixing layer by crosslinking with the polyvinyl alcohol-based adhesive. Examples of the crosslinking agent include various known crosslinking agents and gelling agents. 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.

In the present invention, boric acid is used as a crosslinking agent for the following reasons. In general, boric acid is also called orthoboric acid. Boric acid (H ₃ BO ₃ ) does not react with polyvinyl alcohol as it is, but in the form of boric acid ions ([H ₄ BO ₄ ] ⁻ ), reacts with polyvinyl alcohol and crosslinks. Boric acid does not become a borate ion in the acidic region, but becomes a borate ion in the presence of alkali. Therefore, even if polyvinyl alcohol and boric acid are allowed to coexist in the ink fixing layer forming coating solution, the crosslinking reaction does not occur as it is, and the coating solution does not gel.

  In the present invention, by applying the ink fixing layer forming coating liquid on the coating layer containing the alkaline substance provided in the pretreatment step, the alkaline substance penetrates into the ink fixing layer forming coating liquid, Boric acid is ionized and activated. Therefore, the crosslinking can be started immediately immediately after the application of the ink fixing layer forming coating liquid, and when the moisture is not so much evaporated, the molecular chains of the polyvinyl alcohol are constrained to change the volume. A lot of water can be evaporated after it becomes difficult to occur. Therefore, in the production method of the present invention, it is considered that the volume change accompanying water evaporation during drying can be suppressed, so that the strain can be reduced and the ink fixing layer can be prevented from cracking.

  In the production method of the present invention, since almost the entire amount of boric acid blended in the ink fixing layer forming coating liquid is activated, the amount of boric acid to be activated is unlikely to fluctuate. Therefore, the degree of crosslinking of the ink fixing layer can be easily adjusted only by the amount of boric acid contained in the ink fixing layer forming coating solution. Therefore, excessive crosslinking and insufficient crosslinking can be easily prevented. In addition, since the flexibility of the ink fixing layer can be secured by preventing excessive crosslinking, even if ink jet recording paper is recorded by a C-type paper feeding type printer, it is difficult for the recording surface to be cracked. Further, by preventing insufficient crosslinking, an ink fixing layer having high practicality can be obtained.

  The content of boric acid is preferably 5 to 20 parts, more preferably 7 to 15 parts per polyvinyl alcohol, although it depends on the polymerization degree of polyvinyl alcohol and the drying conditions. 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.

[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.

[Manufacture of ink fixing layer]
The pH at 25 ° C. of the ink fixing layer forming coating solution is preferably 3.0 or more and more preferably 5.0 or less. If the pH of the ink fixing layer forming coating liquid is equal to or higher than the lower limit value, boric acid is easily activated after coating the ink fixing layer forming coating liquid, and polyvinyl alcohol can be crosslinked more quickly. On the other hand, if the pH of the coating solution for forming the ink fixing layer is equal to or lower than the above upper limit, activation of boric acid contained in the coating solution for forming the ink fixing layer before coating can be suppressed, and thickening can be prevented. Coating defects can be prevented.
In order to adjust the pH of the ink fixing layer forming coating solution to 3.0 or more and 5.0 or less, components that change the hydrogen ion concentration in the ink fixing layer forming coating solution (for example, cationic compounds) ) May be adjusted. For example, as the addition amount of the cationic compound is increased, the pH is lowered. Moreover, you may suppress the fall of pH by reducing the addition amount of the component with low pH, or not adding.

Dry the solid coating amount of the ink-fixing layer forming coating liquid is preferably from 2~100g / m ^2, and more preferably 5 to 50 g / m ^2. When the coating amount is equal to or greater than the lower limit value, the ink absorbability of the ink fixing layer is sufficient, and when the coating amount is equal to or less than the upper limit value, cracking of the fixing layer can be further prevented.
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 various coating apparatuses such as 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. The pre-weighing type die coater is preferable because there is no coating liquid that is measured and returned on the paper surface, so there is no need to worry about inadvertent thickening due to mixing with the ink fixing layer coating liquid in contact with the pH adjustment layer. .
The drying method after applying the ink fixing layer forming coating liquid is not particularly limited, and for example, heat drying with hot air, radiant heat drying with infrared irradiation, or the like can be applied. The ink fixing layer formed by the ink fixing layer forming step may be subjected to a smoothing process such as super calendering or brushing as necessary.

<Glossy expression layer forming process>
In the gloss developing layer forming step, a coating liquid containing anionic colloidal silica is applied on the ink fixing layer and then cast finish.

[Anionic colloidal silica]
Generally, the pigment used in the gloss developing layer uses colloidal particles. Colloidal particles refer to inorganic particles or organic particles that are suspended and dispersed in water to form a colloidal shape. By containing colloidal particles, uniform and high gloss can be obtained. Colloidal particles include, for example, colloidal silica, boehmite, pseudoboehmite and other alumina sols, colloidal alumina, cationic aluminum oxide or hydrates thereof, or colloidal materials disclosed in Japanese Patent Publication No. 47-26959. Inorganic particles such as alumina-coated particles on the surface of silica particles, polystyrene, methyl methacrylate, styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer, acrylic acid ester and methacrylic acid ester copolymer, microcapsules, urea resin And organic particles such as melamine.

Among them, anionic colloidal silica is used in the present invention. Since colloidal silica has a low refractive index, it is easy to obtain a high recording density. By using anionic colloidal silica, it is possible to solve productivity problems such as drum haze and releasability.
The particle diameter of colloidal silica is preferably about 5 to 300 nm, and more preferably 7 to 100 nm. The shape includes a spherical shape, a bowl shape, a bead shape, and the like, and is not particularly limited, and can be used in combination. Moreover, a well-known pigment can also be used together in the range which does not inhibit the effect of this invention.

〔adhesive〕
Some anionic colloidal silicas have self-adhesive properties, so an adhesive is not always necessary, but in order to prevent the glossy layer from peeling off or falling off during use, the colloidal layer contains a colloidal material. It is preferable to add an adhesive for the purpose of fixing silica on the ink fixing layer.
The glossy layer contains an adhesive for the purpose of fixing colloidal particles or the like on the ink fixing layer.
Examples of the adhesive include water-dispersed adhesives such as styrene-butadiene copolymer resins, methyl methacrylate-butadiene copolymer conjugated diene resins, acrylic resins, and vinyl resins such as ethylene-vinyl acetate copolymer resins. Proteins such as casein, soy protein, gelatin, synthetic protein, various starches such as starch and oxidized starch, various polysaccharides such as chitin and chitosan, modified polyvinyl such as polyvinyl alcohol, cationic polyvinyl alcohol, silyl modified polyvinyl alcohol Water-soluble adhesives such as polyvinyl alcohols containing alcohol, cellulose derivatives such as carboxymethylcellulose and methylcellulose, aqueous polyurethane resins, and aqueous polyester resins are known and can be used. Among these, polyvinyl alcohol, casein, and an anionic adhesive are preferable because they do not easily inhibit ink absorption, do not impair transparency, and easily obtain high gloss.

  The compounding quantity of an adhesive agent is adjusted in 1-50 mass parts with respect to 100 mass parts of anionic colloidal silica, More preferably, it is adjusted in the range of 10-30 mass parts. If the blending amount of the adhesive is less than 1 part by mass, the adhesive strength of the glossy layer is weakened and the coating layer may be lost. If the amount exceeds 50 parts by mass, the ink absorptivity is reduced and desired. Ink jet recording suitability may not be obtained, which is not preferable.

〔Release agent〕
The gloss developing layer is cast paper raised, that is, the coating liquid for the gloss developing layer is applied, and while the coated surface is in a wet state, the coated surface is pressed against a heated mirror roll and dried, and then the mirror drum More peeled. In order to smoothly separate the coating surface and the mirror drum, it is preferable to add a release agent to the coating liquid.
Examples of mold release agents include higher fatty acid amides such as stearic acid amide and oleic acid amide, polyolefin waxes such as polyethylene wax, oxidized polyethylene wax and polypropylene wax, calcium stearate, zinc stearate, potassium oleate, and ammonium oleate. Examples thereof include higher fatty acid alkali salts, silicone compounds such as lecithin, silicone oil and silicone wax, and fluorine compounds such as polytetrafluoroethylene.

  The compounding quantity of a mold release agent is 0.1-50 mass parts with respect to 100 mass parts of pigments, Preferably it is 0.3-30 mass parts, More preferably, it adjusts in the range of 0.5-20 mass parts. Here, if the blending amount is small, it is difficult to obtain the effect of improving the releasability. On the other hand, if the blending amount is large, the gloss may be lowered or the ink repellency or the recording density may be lowered.

[Other additives]
In the coating composition for forming the glossy layer, pigments and antifoaming agents used for general printing coated papers and inkjet papers for adjusting whiteness, viscosity, fluidity, etc. Various auxiliary agents such as colorants, fluorescent brighteners, antistatic agents, preservatives and dispersants, and thickeners are appropriately added.
Various known coating methods can be adopted as a method for coating the gloss developing layer coating solution. For example, a coating device such as a blade, brush coater, Champlex coater, bar coater or gravure coater is appropriately used. Good.

Dry coating amount of the glossy layer, and quality of glossiness and print density, is preferably about 0.1-5 g / ^{m 2} from the balance of ink absorption, more preferably at 0.3 to 3 g / ^{m 2} . High glossiness is sufficiently obtained with such a small coating amount. When the dry coating amount is less than 0.1 g / m ² , sufficient glossiness and print density cannot be obtained. On the other hand, when the coating amount is excessive, the image sharpness decreases due to the deterioration in ink absorbability and the drying load There is a risk that productivity will deteriorate due to the increase.

[Cast finish]
The glossy layer is cast-finished after a coating liquid containing the above components is applied and dried.
In general, cast finish means that the coating layer is dried by pressing it onto a cast drum having a mirror finish (drum made of mirror finish metal, plastic, glass, etc.), mirror finish metal plate, plastic sheet, film, glass plate, etc. The mirror surface is copied onto the coating layer to obtain a smooth and glossy coating layer surface.
The method of expressing gloss by cast finishing using a cast drum heated in this,
(A) A method of applying a gloss developing layer coating liquid onto a substrate, pressing the dried coating liquid while the coating liquid is in a wet state, and drying to finish (wet casting method),
(B) A method in which the outermost coating layer coated on the substrate is once dried, then the outermost coating layer is rewet, and then pressed onto a heated cast drum and dried to finish (rewet casting method). ,
(C) The outermost coating layer on the substrate is gelled to form a gel-like coating layer, which is pressed onto a heated cast drum and dried to finish (gelled casting method),
(2) Apply the coating solution for the outermost coating layer directly to the heated cast drum, dry it and form the outermost coating layer on the cast drum, and then press the cast drum onto the substrate And finishing by transferring the outermost coating layer (precast method),
Is mentioned.
In these cast finishes, the temperature of the heated cast drum is, for example, 50 to 150 ° C, preferably 70 to 120 ° C.

Furthermore, a film transfer method can be adopted as the cast finish.
What is film transfer system?
(A) The above-mentioned coating liquid for the outermost coating layer is applied onto a substrate, and a smooth film or sheet is layered and dried while the coating liquid is in a wet state. How to peel off and finish,
(B) Apply the coating solution for the outermost coating layer on a smooth film or sheet, press the substrate surface to be bonded to a certain degree of moisture, and press and dry the substrate surface. And then finishing by peeling off a smooth film or sheet.
Compared with the film transfer method, the cast method using a heated cast drum tends to be superior in surface smoothness and is more advantageous in terms of productivity and cost.

  Any of the above methods may be used for the cast finish. However, in the ink jet recording paper of the present embodiment, the above-described ink fixing layer coating solution is an alkaline solution formed on a gas-permeable substrate or undercoat layer. It is preferable to use a wet casting method in which the coated surface is coated and dried, and the gloss developing layer coating liquid is coated on the ink fixing layer, and then immediately pressed against a heated mirror surface metal drum and dried. For example, when the gloss developing layer coating liquid is applied at the nip portion when the sheet on which the ink fixing layer is formed is pressed against the cast drum, the water in the gloss developing layer coating liquid becomes a highly absorbent ink fixing layer. This is preferable because it can prevent the penetration effect. In this wet casting method, a uniform coating layer is easily formed, and a glossy expression layer having a high printing density and excellent gloss is easily obtained.

<Back layer>
In the present invention, the back layer is provided on the back surface on the other surface side of the base material not provided with the above-described gloss developing layer or the like in order to improve the texture of the photograph, the curl prevention of the ink jet recording paper and the transportability. It may be provided. Although it does not specifically limit to a back layer, A pigment and binder type | system | group (For example, colloidal silica and an acrylic emulsion type binder etc.), Organic emulsion type (For example, a silicone type emulsion type binder, an acrylic type emulsion type binder, etc.) And a hydrophilic / hydrophobic adhesive system (for example, a coating film of starch or polyvinyl alcohol), a laminate (for example, polyethylene) or the like.

  In addition, inkjet recording paper and other recording media are bonded to the back side to form a double-sided recording paper, an adhesive layer is formed on the back side to form a label, and the card is bonded to the surface of a magnetic card or IC card. Well-known means can be applied.

  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 indicate “parts by mass” and “% by mass” of solids excluding water, respectively, unless otherwise specified.

[Amorphous silica A: treated with a silane coupling agent containing an amino group]
Gas phase method silica (product name: Aerosil A300, product name: Aerosil A300, average primary particle size: about 8 nm) having an average particle size of 1.0 μm is dispersed with a homomixer, and then high-speed collision is performed until the average particle size reaches 50 nm. By pulverizing and dispersing with a type homogenizer, an aqueous dispersion of 10% by mass of silica was prepared.
5 parts of γ-aminopropylmethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM-903) and 2 parts of lactic acid are added to 100 parts by weight of the 10% by weight aqueous dispersion, and further added with a high-speed collision type homogenizer. A 10% by mass aqueous dispersion of a silica-cationic compound having an average particle size of 0.10 μm was prepared.

[Amorphous silica B: treated with a silane coupling agent containing a quaternary ammonium group]
Gas phase method silica (product name: Aerosil A300, product name: Aerosil A300, average primary particle size: about 8 nm) having an average particle size of 1.0 μm is dispersed with a homomixer, and then high-speed collision is performed until the average particle size reaches 50 nm. By pulverizing and dispersing with a type homogenizer, an aqueous dispersion of 10% by mass of silica was prepared.
To 100 parts by mass of the 10% by mass aqueous dispersion, 5 parts of octadecyldimethyl-γ-trimethoxysilylammonium chloride (manufactured by Toray Dow Corning Silicone Co., Ltd., trade name: AY43-021) and 2 parts of lactic acid are added, The dispersion was further dispersed by a high-speed flow collision type homogenizer to prepare a 10% by mass aqueous dispersion of a silica-cationic compound having an average particle size of 0.10 μm.

[Amorphous silica C: treated with cationic resin]
Gas phase method silica (product name: Aerosil A300, product name: Aerosil A300, average primary particle size: about 8 nm) having an average particle size of 1.0 μm is dispersed with a homomixer, and then high-speed collision is performed until the average particle size reaches 50 nm. By pulverizing and dispersing with a type homogenizer, an aqueous dispersion of 10% by mass of silica was prepared.
10 parts by mass of a cationic resin having a five-membered ring amidine structure (trade name: Himax SC700M, molecular weight 30,000) having a 5-membered ring amidine structure is 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.

[Amorphous silica D: treated with cationic resin]
Gas phase method silica (product name: Aerosil A300, product name: Aerosil A300, average primary particle size: about 8 nm) having an average particle size of 1.0 μm is dispersed with a homomixer, and then high-speed collision is performed until the average particle size reaches 50 nm. By pulverizing and dispersing with a type homogenizer, an aqueous dispersion of 10% by mass of silica was prepared.
10 parts by mass of diallyldimethylammonium chloride-acrylamide copolymer (trade name: PAS-J-81, manufactured by Nitto Boseki Co., Ltd.) is added to 100 parts by mass of the 10% by mass aqueous dispersion, and a high-speed flow collision type homogenizer is added. And a 10% by mass aqueous dispersion of a silica-cationic compound having an average particle size of 0.10 μm was prepared.

<Example 1>
[Manufacture of air-permeable substrates]
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 (permeable base material) having a basis weight of 180 g / m ² was produced using a papermaking material comprising 5 parts by mass and 0.75 part by mass of starch using a long net paper machine.

[Pretreatment process]
The following alkaline solution was applied to the obtained paper base so that the coating amount after drying was 1.5 g / m ² and dried with an IR heater.
"Preparation of alkaline solution"
100 parts of diethanolamine (made by Kishida Chemical Co., Ltd., reagent), 0.2 parts of wetting agent (made by Lion Co., Ltd., trade name: Leox 2160C), defoaming agent (manufactured by San Nopco Co., Ltd., trade name: Nopco) 1407K) 0.05 parts was added and dispersed to prepare an alkaline solution A having a solid concentration of 12%. The pH of this alkaline solution was 10.5.

[Ink fixing layer forming step]
The following ink fixing layer forming coating liquid A was applied and dried so that the coating amount after drying was 18 g / m ² to form an ink fixing layer.

“Preparation of coating solution A for forming an ink fixing layer”
To 100 parts of the amorphous silica A, 2 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 parts), 20 parts of wetting material (trade name: Emulgen 709, manufactured by Kao Corporation), and 0.5 part of antifoaming agent (trade name: SN Deformer 777, manufactured by San Nopco). Were mixed and stirred to prepare a coating liquid A for forming an ink fixing layer having a solid content concentration of 12%. The pH of the ink fixing layer forming coating solution was 3.5.

[Glossy layer forming process]
The following glossy layer coating liquid A is applied to the surface of the ink fixing layer at the nip portion of the cast drum, then immediately pressed against a mirror drum having a surface temperature of 95 ° C., dried, and peeled to obtain a glossy inkjet recording paper. Produced. At this time, the dry coating amount of the glossy layer was 1 g / m ² .
"Preparation of glossy layer coating liquid A"
Anionic colloidal silica in water (Nissan Chemical Co., Ltd., trade name: Snowtex 20L, average particle size: 45 nm, primary particles) 100 parts, acrylic resin (manufactured by Nichigo Movinyl Co., Ltd.), product Name: Movinyl 5400) 15 parts, Casein (manufactured by Nissei Kyobentsu Co., Ltd., trade name: Arashid) 5 parts, polyethylene emulsion as a water dispersible release agent (manufactured by San Nopco Co., Ltd., trade name: Nopcoat PEM-17) 10 parts, 5 parts of ammonium stearate (product name: DEF-116T, manufactured by Nissin Chemical Laboratory Co., Ltd.) as a water-soluble substance is added and mixed to obtain a coating liquid A for glossy layer having a solid content concentration of 5%. Prepared.

Example 2
A glossy inkjet recording paper was prepared in the same manner as in Example 1 except that the amorphous silica A was changed to the amorphous silica B in “Preparation of coating liquid A for forming an ink fixing layer” in Example 1. .

Example 3
A glossy ink jet recording paper was prepared in the same manner as in Example 1 except that diethanolamine in the alkaline solution was changed to monoethanolamine (manufactured by Kishida Chemical Co., Ltd., reagent). The pH of this alkaline solution was 11.5.

Example 4
A glossy inkjet recording paper was prepared in the same manner as in Example 1 except that diethanolamine in the alkaline solution was calcium hydroxide (made by Kishida Chemical Co., Ltd., reagent) and the concentration was changed to 1%. The pH of this alkaline solution was 12.0.

Example 5
A glossy ink jet recording paper was prepared in the same manner as in Example 1 except that diethanolamine in the alkaline solution was sodium hydroxide (made by Kishida Chemical Co., Ltd., reagent) and the concentration was changed to 1%. The pH of this alkaline solution was 12.5.

Comparative Example 1
A glossy inkjet recording paper was prepared in the same manner as in Example 1 except that the “pretreatment step” was omitted in Example 1.

Comparative Example 2
A glossy inkjet recording paper was prepared in the same manner as in Example 1 except that the amorphous silica C was used in place of the amorphous silica A in “Preparation of coating liquid A for forming an ink fixing layer” in Example 1. Produced.

Comparative Example 3
A glossy inkjet recording paper was prepared in the same manner as in Example 1 except that the amorphous silica D was used in place of the amorphous silica A in “Preparation of coating liquid A for forming an ink fixing layer” in Example 1. Produced.

Comparative Example 4
A glossy ink jet recording paper was produced in the same manner as in Example 1 except that the following glossy expression layer forming step was used.
[Glossy layer forming process]
After the gloss developing layer coating liquid B shown below is applied to the ink fixing layer surface at the nip portion of the cast drum, it is immediately pressed against a mirror drum having a surface temperature of 95 ° C., dried, and peeled to obtain a glossy inkjet recording paper. Produced. At this time, the dry coating amount of the glossy layer was 1 g / m ² .
"Preparation of glossy layer coating liquid B"
Cationic colloidal silica (manufactured by Nissan Chemical Co., Ltd., trade name: Snowtex AKL, average particle size 45 nm, primary particle) 100 parts in water, cationic urethane resin (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an adhesive , Trade name: Superflex 650) 15 parts, cationic polyethylene emulsion (Senka Co., Ltd., trade name: Sophair C) 15 parts as a water-dispersible release agent was added and mixed, and the solid content concentration was 5%. A coating liquid B for glossy layer was prepared.

Comparative Example 5
A glossy ink jet recording paper was produced in the same manner as in Example 1 except that the following glossy expression layer forming step was used.
[Glossy layer forming process]
The gloss developing layer coating liquid C shown below was coated on the surface of the ink fixing layer with an air knife coater, dried, and then calendered with a calendar device having a surface temperature of 95 ° C. to prepare a glossy ink jet recording paper. At this time, the dry coating amount of the glossy layer was 1 g / m ² .
“Preparation of glossy layer coating liquid C”
Anionic colloidal silica in water (Nissan Chemical Co., Ltd., trade name: Snowtex 20L, average particle size 45 nm, primary particles) 100 parts, acrylic resin as an adhesive (manufactured by Nichigo Movinyl Co., Ltd., trade name) : Movinyl 5400) 15 parts and Casein (manufactured by Nissei Kyoben Co., Ltd., trade name: Arashid) 5 parts were added and mixed to prepare a coating liquid C for glossy expression layer having a solid content concentration of 5%.

Comparative Example 6
In the same manner as in Example 1, a support was obtained, and the following borax solution was applied so that the coating amount after drying was 1.5 g / m ² , dried with an IR heater, and further the following ink fixing layer: The forming coating liquid B was applied and dried so that the coating amount after drying was 18 g / m ² to form an ink fixing layer. Next, a glossy expression layer was formed in the same manner as in Example 1 to produce a glossy inkjet recording paper.
"Preparation of borax solution"
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 crosslinker solution was prepared. The pH of this coating solution was 12.0.
“Preparation of Ink Fixing Layer Coating Liquid B”
100 parts of amorphous silica A, PVA as an adhesive (product name: PVA-145, polymerization degree 4500, saponification degree 99%) 10 parts, antifoaming agent (manufactured by San Nopco Co., Ltd., product) Name: SN deformer 777) 0.1 part was mixed and stirred to prepare an ink fixing layer coating solution having a solid content of 12%.

<Evaluation method>
The sharpness of the recorded image on the glossy inkjet recording paper, the scratch resistance at the time of feeding the printer, the glossiness, and the productivity were evaluated by the following methods, and the results are shown in Table 1.
Note that the clarity of the recorded image was evaluated by measuring the color density of the recorded image.
For the ink jet printer, CANON Co., Ltd., trademark: iP-4200, printing mode: glossy paper, standard, non-matching mode was used.

“Clarity of recorded image (print density)”
Solid printing was performed with black ink on glossy inkjet recording paper, and the color density was measured with a Macbeth reflection densitometer (model: Gretag Macbeth RD-19, manufactured by Macbeth).

"Scratch resistance when feeding printers (cracking resistance)"
With a paper feeding method (C-type paper feeding) in which glossy inkjet recording paper is set in a paper feed tray below the printer iP4200 with the printing surface facing downward, the recording paper is rotated inside the printer and the printing surface faces upward, and printing is performed. After printing with solid black on the entire surface of the recording paper, the surface of the printed part was visually observed for scratches.
5: No cracks are seen.
4: Although the crack is seen a little, it is a level which is satisfactory practically.
3: Although there are a few cracks, there is no practical problem.
2: There are many cracks and a practically problematic level.
1: There are very many cracks, and it cannot be put to practical use.

"Glossiness"
For the evaluation of the 20-degree specular gloss, the recording paper surface was measured at an incident / reflection angle of 20 degrees using a digital gloss meter (GM-26D) manufactured by Murakami Color Research Laboratory in accordance with JIS-P8741.

"Drum cloudy"
After coating and solidifying the outermost layer of glossy inkjet recording paper, it is pressure-bonded to a cast drum heated to a surface temperature of 95 ° C, and after 10 seconds, the inkjet recording paper is peeled off from the cast drum, and the inkjet recording paper is coated on the mirror surface. The following criteria evaluated whether there was any residue of the layer.
5: There is no residue on the drum surface.
4: There is almost no residue on the drum surface.
3: Residue is slightly observed on the drum surface, but can be produced normally.
2: Many residues are observed on the drum surface.
1: A very large amount of residue adheres to the drum surface, and the gloss of the drum surface is lost.

"Releasability"
After coating and solidifying the glossy expression layer of the glossy inkjet recording paper, it is pressure-bonded to a cast drum heated to a surface temperature of 95 ° C., and the cast coater is operated at a speed at which the glossy inkjet recording paper is peeled off from the cast drum after 10 seconds. 1,000 m was applied, the state of mold release was observed, and the following criteria were evaluated.
5: There was no problem with mold release, and the operation was extremely smooth.
4: The mold release was somewhat forcibly separated from the drum surface, but was able to operate smoothly.
3: The mold release was forcibly separated from the drum surface, but could be operated without damage to the paper surface.
2: The mold release was forcibly separated from the drum surface, and some damage to the paper surface was observed.
1: The coating layer did not peel from the drum surface but remained on the drum surface, so-called drum pick occurred, and operation of 1,000 m was not possible.

  As is apparent from Table 1, the glossy ink jet recording paper of this example has a high recording density, is not easily broken during C-type feeding of the printer, and is excellent in productivity. On the other hand, it was found that the comparative example was evaluated as a practically problematic level for any of the evaluation items.

  INDUSTRIAL APPLICABILITY The present invention provides a glossy type ink jet recording paper excellent in productivity, and is used as, for example, an output paper of a dye ink type ink jet printer and a pigment ink type ink jet printer which perform quick ink ejection and record photographic image quality. Is done.

Claims (4)

On the air-permeable substrate or on at least one subbing layer formed on the air-permeable substrate,
A pretreatment step in which an alkaline solution is applied in advance;
An ink fixing layer forming step of coating an amorphous silica treated with a silane coupling agent containing an amino group or a quaternary ammonium group, a polyvinyl alcohol-based resin, and an ink fixing layer forming coating solution containing boric acid; and ,
After applying a coating solution containing an anionic colloidal silica, a gloss developing layer forming step of casting finish,
A method for producing a glossy ink jet recording paper having: The method for producing a glossy ink jet recording paper according to claim 1, wherein the silane coupling agent is an ethoxysilane compound having an amino group. The method for producing a glossy ink jet recording paper according to claim 1 or 2, wherein the amorphous silica is vapor phase method silica. The method for producing a glossy inkjet recording paper according to any one of claims 1 to 3, wherein the alkaline solution contains an ethanolamine and / or a salt of an alkaline earth metal.