JP2006035825A - Recording medium for inkjet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recording medium for inkjet, which has long-term image stability and clear image characteristics. <P>SOLUTION: This recording medium for the inkjet is equipped with a substrate, and an ink absorbing layer which is formed on the substrate, and which includes a pigment for retaining a color material for ink, a binder for binding the pigment, and a component for preventing the deterioration of the color material. In the recording medium, at least two kinds of compatible materials for preventing the deterioration of the color material are included as the component for preventing the deterioration of the color material, and at least one kind of material for preventing the deterioration of the color material is a liquid at room temperature. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention provides an ink jet recording medium suitable for recording using water-based ink. In particular, the present invention relates to an ink jet recording medium having long-term image storage stability and excellent image characteristics. .

  The ink jet recording method is a method for recording images, characters, etc. by causing micro droplets of a recording liquid (recording liquid) such as ink to fly by various operating principles and adhere to a recording medium such as paper. It has features such as high speed, low noise, easy multi-coloring, great flexibility in recording patterns, and no development required. It can be used for printers, copiers, word processors, facsimiles, and plotters. Development to the output section of information equipment such as the above has been further performed and is rapidly spreading. In recent years, high-performance digital cameras, digital videos, scanners, etc. are being offered at low cost, and coupled with the widespread use of personal computers, printers that employ inkjet recording methods for the output of image information obtained from them are extremely suitable. It has come to be used. In such a background, it has been required to easily output an image that is inferior to that of silver salt photography or plate-making multicolor printing by an inkjet recording method.

  In order to meet these requirements, improvements have been made to the structure and recording method of the printer itself, such as high-speed recording, high definition, and full color, and improvements to the structure and characteristics of the recording medium have been actively studied. Has been.

  Various types of recording media have been proposed for recording media used in ink jet recording and the like. A recording medium comparable to a silver salt type photograph is required to form an image having excellent dye coloring property, high surface glossiness, and high resolution. As a constituent material of an ink receiving layer of a recording medium capable of providing an image comparable to a silver salt photograph, for example, alumina hydrate can be mentioned, and is described in Patent Document 1 and the like.

  Furthermore, recently, the storability of recorded images has been required. In order to improve light resistance and gas resistance, a method for improving the storage stability of a recorded image including a color material deterioration preventing material has been proposed.

For example, as a method for improving the storage stability of image light and gas in the air, Patent Document 2 discloses a recording sheet containing a special cationic compound, Patent Document 3, Patent Document 4, Patent Document 5, Patent Document 6, and the like. Discloses a recording sheet containing a hindered amine compound as a light resistance improver. Further, Patent Document 7 describes that the effect of the anti-fading agent is enhanced by using a compound such as dithiocarbamate having an anti-fading effect and a quencher composed of iodine or iodide.
JP-A-7-232475 Japanese Patent Publication No. 6-30951 Japanese Patent Laid-Open No. 3-13376 Japanese Patent Publication No. 4-34512 JP-A-11-245504 JP 2001-121812 A Japanese Patent No. 3435804

  In order to achieve both long-term image preservation and image clarity, it is necessary to solve the following problems.

  Although a conventionally known method can achieve a certain degree of weather resistance improvement, in order to further improve the image storage stability over a long period of time, it has been necessary to use a large amount or a plurality of colorant deterioration preventing materials. The use of a large amount of the additive has a problem that the transparency of the ink receiving layer is lowered and a clear image cannot be formed or the ink absorbability is lowered.

  Further, when a plurality of additives are used, the transparency of the ink receiving layer may be lowered, and a clear image may not be formed. Although this mechanism is not clear, it is conceivable that a region having a different refractive index increases or bubbles are taken into the additive.

  An object of the present invention is to provide an ink jet recording medium having both long-term image storage stability and excellent image recording characteristics.

The present invention
Inkjet recording comprising: a base material; and a pigment formed on the base material for holding a colorant of ink, a binder for binding the pigment, and an ink receiving layer containing a colorant deterioration preventing component In the medium, the ink composition includes at least two compatible color material deterioration preventing materials as the color material deterioration preventing component, and at least one of the color material deterioration preventing materials is liquid at room temperature. Recording medium.

  According to the present invention, it is possible to provide an inkjet recording medium having long-term image storage stability and clear image characteristics.

  Hereinafter, the present invention will be described in more detail with reference to preferred embodiments.

(Embodiment of the Invention)
The present invention includes a base material, and a pigment formed on the base material for holding a color material of ink, a binder for binding the pigment, and an ink receiving layer containing a color material deterioration preventing component. The present invention relates to a recording medium for inkjet.

  First, an embodiment related to the coloring material deterioration preventing component will be described.

  In the present invention, at least two compatible color material deterioration preventing materials are used as the color material deterioration preventing component, and at least one of the color material deterioration preventing materials is liquid at room temperature.

  The color material deterioration preventing material in the present invention refers to a compound that, when present together with a dye in the ink receiving layer, protects the dye from factors that deteriorate the dye such as gas and light and improves the weather resistance of the dye. Further, “compatible” means a state in which no cloudiness or phase separation occurs even when the solvent is evaporated after being dissolved in a solvent or the like. That is, for example, not only the case where the liquids are compatible with each other but also the case where the solid is dissolved in the liquid to form a uniform solution. Room temperature refers to 25 ° C.

  When two or more compatible colorant deterioration preventing materials are included in the ink receiving layer, and at least one of them is liquid at room temperature, higher fastness is exhibited compared to when used alone. The transparency of the ink-receiving layer is not so, that is, when only a solid color material deterioration preventing material is used as a color material deterioration preventing component, or even if a liquid color material deterioration preventing material is included, it is not compatible. The printed image is high in density and vivid. Although this mechanism is not clear, it is presumed as follows. When two or more compatible color material deterioration prevention materials are contained in the ink receiving layer and at least one of the color material deterioration prevention materials is a liquid, the other of the liquid color material deterioration prevention materials into the liquid color material deterioration prevention material The colorant deterioration preventing material dissolves and promotes dispersion in the ink receiving layer. Therefore, after printing, since the color material deterioration preventing material exists also in the vicinity of the ink color material existing in the ink receiving layer, the color material deterioration preventing effect can be effectively expressed, and two or more kinds of color materials Since the deterioration preventing material is in a compatible state, it is considered that the region having a different refractive index is reduced as compared with the case where each material is deposited in the pores in the ink receiving layer, and the transparency of the ink receiving layer is increased. When using only a solid color material deterioration preventing material as a color material deterioration preventing component, or even if a liquid color material deterioration preventing material is included, the phenomenon different from the above occurs, and the ink receiving layer It is thought that transparency tends to be low. In addition, in the coating process, since the color material deterioration preventing material used is a liquid in a compatible state, it is difficult to capture air bubbles during coating and drying compared to the case where it is solid, and has excellent transparency. Can be manufactured.

  General examples of colorant deterioration prevention materials include hindered amine compounds, hindered phenol compounds, phosphite compounds, thiuram compounds, thioether compounds, thiourea compounds, benzophenone compounds, benzotriazole compounds Examples thereof include, but are not limited to these. Preferably, at least two selected from the group consisting of hindered amine compounds, hindered phenol compounds, phosphite compounds, thiuram compounds and thioether compounds are preferably used. Among these, it is more preferable to include at least a hindered amine compound.

  In the present invention, at least one of the colorant deterioration preventing materials is liquid at room temperature. Examples of the colorant deterioration preventing material that is liquid at room temperature are given below.

  As a hindered amine compound,

However, it is not limited to these.

  As phosphite compounds,

However, it is not limited to these.

  As thiuram compounds,

However, it is not limited to these.

  As thioether compounds,

However, it is not limited to these.

  Among the above-described materials, the most preferable material for preventing colorant deterioration that is liquid at room temperature is a phosphite compound that has an excellent effect on light resistance of an ink jet recorded image.

  Further, as one of the more preferable embodiments in the present invention, mixing of the color material deterioration preventing material when two or more kinds of color material deterioration preventing materials present in the ink receiving layer are mixed at an abundance ratio in the ink receiving layer. The viscosity of the liquid is in the range of 100 to 10,000 mPa · s. By controlling the viscosity within this range, it is possible to achieve good dispersibility of the colorant deterioration preventing material in the ink receiving layer and prevention of movement over time.

  Therefore, it is preferable to control at least the above-mentioned optimum viscosity range by combining at least one kind of colorant deterioration preventing material that is solid at room temperature. Furthermore, it is preferable to combine a colorant deterioration preventing material that is solid at room temperature because the viscosity of the mixed solution tends to increase and a large amount of the colorant deterioration preventing material tends to exist near the surface. Examples of the colorant deterioration preventing material that is solid at room temperature are given below.

  As a hindered phenol compound,

However, it is not limited to these.

  As a hindered amine compound,

However, it is not limited to these.

  As phosphite compounds,

However, it is not limited to these.

  As thioether compounds,

However, it is not limited to these.

  As thiuram compounds,

However, it is not limited to these.

  Among the above, hindered amine compounds are the most preferable as colorant deterioration preventing materials that are solid at room temperature.

  The best combination of the colorant deterioration preventing materials in the present invention is a combination including at least a phosphite compound and a hindered amine compound, and at least one of which is liquid at room temperature.

  The preferable content of the entire colorant deterioration preventing component in the ink receiving layer is preferably in the range of 0.5 to 10% by mass with respect to the pigment solid content. The lower limit is preferable in terms of the fading suppression effect, and the upper limit is preferable in terms of ink absorbency. More preferably, it is 2-8 mass%.

  Although there is no restriction | limiting in particular about the compounding ratio of 2 or more types of color material deterioration prevention materials used by this invention, Each color material deterioration prevention material becomes the range of 10-90 mass% with respect to the whole color material deterioration prevention component. It is preferable to blend as described above.

  In the present invention, as a method for adding the color material deterioration preventing material to the ink receiving layer, at least one color material deterioration preventing material is a liquid, and two kinds of color material deterioration preventing materials are dissolved in an organic solvent or the like. The color material deterioration preventing material solution may be applied on an ink receiving layer formed in advance with components other than the color material deterioration preventing material. The solid content concentration of the color material deterioration preventing material is easily 0.5 to 30% by mass. From the viewpoint of the appearance of the inkjet recording medium after finishing, the hindered amine coating method is preferably a non-contact coating method with respect to the receiving layer surface, and examples thereof include a die coater, an air knife coater, and a spray. In addition, a contact-type coating method such as a roll coater, a bar coater, or a gravure coater can also be used.

  The organic solvent for dissolving the colorant deterioration preventing material in the present invention is not particularly limited, but esters such as ethyl acetate and butyl acetate, ketones such as methyl isobutyl ketone, methyl ethyl ketone and acetone, diethyl ether, Examples include ethers such as ethyl methyl ether, and alcohols such as isopropanol, methanol, and ethanol. Further, when the coloring material deterioration preventing material is hydrophilic, water may be used as a solvent. When using water, it is preferable to use pure water.

  As another method, the prepared colorant deterioration preventing material solution may be added to the raw material coating solution for the ink receiving layer and coated as a coating solution containing all components.

As a preferable form, the concentration of the colorant deterioration preventing component includes two parts having different concentrations of the colorant deterioration preventing component, and among these parts, the higher concentration part having the higher concentration of the colorant deterioration preventing component has a concentration of the colorant deterioration preventing component. A configuration in which the ink receiving layer is positioned closer to the recording surface in the depth direction than the lower low density portion can be exemplified. By doing so, the effect of the colorant deterioration preventing material can be sufficiently exhibited. More preferably, the colorant deterioration preventing component preferably has a density distribution that gradually decreases from the recording surface side of the ink receiving layer. By doing so, since the color material deterioration preventing material is present along the penetration of the color material, the effect can be further exhibited. That is, since the color material deterioration preventing material exists in the neighborhood of the color material after recording, the effects of gas resistance and light resistance by the color material deterioration preventing material are more effectively expressed. More preferably, it is desirable that the density of the highest density portion of the coloring material deterioration preventing component is 1.5 times or more the density of the lowest density portion.

  Next, an ink receiving layer containing the color material deterioration preventing material as described above as a color material deterioration preventing component will be described in detail.

  The ink receiving layer is formed of a pigment and a binder in addition to the color material deterioration preventing component as described above.

  As the pigment, it is particularly preferable to contain alumina hydrate as a main component in terms of dye fixing property, transparency, printing density, color developability, and glossiness, but the following pigments can also be used. Examples of inorganic pigments include light calcium carbonate, heavy calcium carbonate, magnesium carbonate, kaolin, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate, synthetic amorphous silica, colloidal silica, alumina, magnesium hydroxide, and other organic pigments. Examples thereof include styrene plastic pigments, acrylic plastic pigments, polyethylene particles, microcapsule particles, urea resin particles, and melamine resin particles. One kind selected from these, or two or more kinds selected as necessary can be used in combination.

  As the alumina hydrate, for example, one represented by the following general formula (1) can be suitably used.

Al ₂ O _3-n (OH) _2n · mH ₂ O (1)
(In the above formula, n represents any of 0, 1, 2, or 3, and m represents a value in the range of 0 to 10, preferably 0 to 5. However, m and n are not 0 at the same time. MH ₂ O often represents a detachable aqueous phase that does not participate in the formation of the crystal lattice, so m can be an integer or non-integer value. M can reach a value of 0 when heated.)
Alumina hydrate is generally produced by hydrolysis of aluminum alkoxide or sodium aluminate as described in US Pat. Nos. 4,242,271 and 4,202,870. Known methods such as a method for performing decomposition, and a method for performing neutralization by adding an aqueous solution such as aluminum sulfate and aluminum chloride to an aqueous solution such as sodium aluminate described in JP-B-57-447605 Can be manufactured. Preferred alumina hydrates in the present invention are alumina hydrates showing a boehmite structure or an amorphous state by analysis by X-ray diffraction, and in particular, JP-A-7-232473 and JP-A-8-132731. And alumina hydrates described in JP-A-9-66664, JP-A-9-76628, and the like.

  In order to give glossiness to the surface of an inkjet recording medium, when the casting process is performed with the ink-receiving layer wet by the rewet method, it is necessary to use a plate-like alumina hydrate having a low orientation tendency. preferable. Since the plate-like alumina hydrate has a good water absorbability, the re-wetting liquid easily penetrates, so that the ink receiving layer swells and the alumina hydrate particles are easily rearranged. Therefore, high glossiness can be obtained. Moreover, since the rewetting liquid penetrates efficiently, the production efficiency at the time of casting is also increased.

  In the present invention, it is preferable to use polyvinyl alcohol as the binder. In addition, modified polyvinyl alcohol, starch or modified product thereof, gelatin or modified product thereof, casein or modified product thereof, gum arabic, carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylmethylcellulose and other cellulose derivatives, SBR latex, NBR latex Conjugated diene copolymer latex such as methyl methacrylate-butadiene copolymer, functional group-modified polymer latex, vinyl copolymer latex such as ethylene vinyl acetate copolymer, polyvinyl pyrrolidone, maleic anhydride or copolymer thereof It is also possible to use a conventionally known binder such as a coalescence or an acrylic ester copolymer. The binder content is preferably 5 to 20% by mass based on the pigment. In the present invention, as the binder used in forming the ink receiving layer, it is also preferable to use a conventionally known binder in combination with the above-described polyvinyl alcohol.

Incorporation of at least one selected from the group consisting of boric acid and borate as a crosslinking agent in the ink receiving layer forming material formed as described above is extremely effective in forming the ink receiving layer. It is. Examples of boric acid that can be used in this case include not only orthoboric acid (H ₃ BO ₃ ) but also metaboric acid and hypoboric acid. The borate is preferably a water-soluble salt of boric acid. Specifically, for example, sodium salt of boric acid (Na ₂ B ₄ O ₇ · 10H ₂ O, NaBO ₂ · 4H ₂ O etc.), potassium salt _{(K 2 B 4 O 7 ·} 5H 2 O, alkali metal salts such KBO _2, etc.), an ammonium salt of boric acid _{(NH 4 B 4 O 9 ·} 3H 2 O, NH 4 BO 2 , etc.) And alkaline earth metal salts such as magnesium salt and calcium salt of boric acid.

  It is preferable to use orthoboric acid from the viewpoint of the temporal stability of the coating solution and the effect of suppressing the occurrence of cracks. Further, the amount of use is preferably in the range of 1.0 to 15.0% by mass of boric acid solid content with respect to the binder in the ink receiving layer. Even within this range, cracks may occur depending on manufacturing conditions and the like, and selection is required. On the other hand, exceeding the above range is not preferable because the temporal stability of the coating solution is lowered. That is, in the case of production, since the coating liquid is used for a long time, if the content of boric acid is large, the viscosity of the coating liquid increases during that time, and the generation of a gelled product occurs. It is necessary to frequently change the coating liquid and clean the coater head, and the productivity is significantly reduced. Furthermore, when the above range is exceeded, for the same reason as the first and second surface treatments described later, in the casting step, a point-like surface (cast surface) defect is likely to occur, and a uniform and good glossy surface is obtained. There may not be.

  The ink receiving layer formed as described above preferably has the pore properties satisfying the following conditions in order to achieve the purpose and effect such as high ink absorbability and high fixability.

First, the pore volume of the ink receiving layer is preferably in the range of 0.1 to 1.0 cm ³ / g. That is, when the pore volume is less than the above range, sufficient ink absorption performance cannot be obtained, resulting in an ink receiving layer with poor ink absorption, and in some cases, ink overflows and bleeding occurs in the image. There is a fear. On the other hand, when it exceeds the above range, there is a tendency that cracks and powder fall off easily occur in the ink receiving layer. The BET specific surface area of the ink receiving layer is preferably ^{20 to} 450 m ² / g. If it is less than the above range, sufficient gloss may not be obtained, and haze increases (transparency decreases), so the image appears to be “white haze”. There is a fear. Furthermore, this case is not preferable because there is a possibility that the adsorptivity of the dye in the ink may be lowered. On the other hand, exceeding the above range is not preferable because cracks are likely to occur in the ink receiving layer. The values of the pore volume and the BET specific surface area are obtained by a nitrogen adsorption / desorption method.

In the case of forming the ink receiving layer, in the present invention, the thickness of the ink receiving layer is more flexible than in the prior art, that is, it can be made thicker than before. Considering high ink absorbability, the dry coating amount is preferably 30 g / m ² or more, and the upper limit is more preferably 50 g / m ² . If it is less than 30 g / m ² , the ink absorption is sufficient especially when used in a printer in which a plurality of light-color inks are added in addition to black ink in addition to the three colors of cyan, magenta, and yellow. In other words, ink overflow may occur and bleeding may occur, or ink dye may diffuse to the base material and print density may decrease. On the other hand, when it exceeds 50 g / m ² , it may occur that the generation of cracks cannot be completely suppressed. Furthermore, if it is 30 g / m ² or more, an ink receiving layer exhibiting sufficient ink absorbency even in a high temperature and high humidity environment can be obtained, and if the dry coating amount is 50 g / m ² or less, ink receiving is possible. The coating unevenness of the layer is further less likely to occur, and an ink receiving layer having a stable thickness can be produced.

  The ink receiving layer as described above is formed on a substrate. Base materials include chemical pulps such as LBKP and NBKP, wood pulp such as GP, PGW, RMP, TMP, mechanical pulp such as CTMP, CMP and CGP, waste paper pulp such as DIP, and synthetic fiber pulp such as polyethylene fiber. As a main component, pigments, sizing agents, fixing agents, yield improvers, paper strength enhancers, and other additives usually used in papermaking are mixed as needed to make a long net paper machine, A base paper produced by various machines such as a net paper machine and a twin-wire paper machine, a base paper provided with a size press or an anchor coat layer with starch, polyvinyl alcohol, etc. on the base paper, and a coat layer provided thereon Coated paper such as art paper, coated paper and cast coated paper is also included. In order to improve the smoothness of the surface of the substrate in order to obtain good recording characteristics and glossiness as an inkjet recording paper, the machine may be provided with an ink receiving layer as it is on such base paper and coated paper. A calendar device such as a calendar, a TG calendar, or a soft calendar may be used in the previous stage of coating the ink receiving layer. Further, as the base material, a polyolefin resin layer may be provided on the base paper, a synthetic resin such as polyethylene, polypropylene, polyester, nylon, rayon, polyurethane, etc., a film material of a mixture thereof, or the synthetic resin as a fiber. Also included are sheets that have been molded.

Example 1
An ink receiving layer was formed on a transparent PET substrate (thickness 250 μm). The coating liquid and the coating method used for forming the ink receiving layer are as follows.

Dispersal HP13 (trade name, manufactured by Sasol Co., Ltd.) as alumina hydrate A was dispersed in water so that the solid content was 5% by mass. Then, hydrochloric acid was added to this to adjust the pH value to 4, followed by stirring for a while. . Thereafter, the dispersion was heated to 95 ° C. while stirring and held at that temperature for 4 hours. Then, while maintaining this temperature, caustic soda was added to adjust the pH value to 10, followed by stirring for 10 hours. Thereafter, the temperature of the dispersion was returned to room temperature, and hydrochloric acid was added to adjust the pH value to 7-8. Further, desalting treatment was performed, and then acetic acid was added to peptize to obtain a colloidal sol. When the alumina hydrate B obtained by drying this colloidal sol was measured by X-ray diffraction, it showed a boehmite structure (pseudo boehmite). At this time, the BET specific surface area was 143 g / m ² , the pore volume was 0.8 cm ³ / g, and it was flat when observed with an electron microscope.

On the other hand, polyvinyl alcohol PVA117 (trade name, manufactured by Kuraray Co., Ltd.) was dissolved in water to obtain an aqueous solution having a solid content of 9% by mass. Then, the colloidal sol of alumina hydrate B prepared above is concentrated to prepare a 22.5 mass% dispersion, and 3 mass% boric acid aqueous solution is added to the solid content of alumina hydrate B. Was added so as to be 0.50% by mass in terms of solid content of boric acid. Thereafter, the obtained boric acid-containing alumina hydrate dispersion and the previously prepared polyvinyl alcohol aqueous solution were mixed with an alumina hydrate solid content and a polyvinyl alcohol solid content ratio of 100: 8 using a static mixer. Immediately after mixing, this was used as a coating solution for the ink receiving layer, and this was coated with a bar coater so that the dry coating amount was 35 g / m ² . And it dried at 80 degreeC and the ink receiving layer was formed, and the recording medium 1 was obtained.

Next, an ink receiving layer provided with 2.25 mass of ADEKA STAB 522A (trade name, manufactured by Asahi Denka Kogyo Co., Ltd.), which is a phosphite compound that is liquid at room temperature, and a hindered amine compound that is solid at room temperature. ADK STAB LA-63P (trade name, manufactured by Asahi Denka Kogyo Co., Ltd.) A MIBK (methyl isobutyl ketone) solution containing 2.25% by mass is 60 m / min so that the coating amount is 1.3 g / m ² with a bar coater. Coated with. And it dried at 80 degreeC and obtained the target recording medium for inkjet.

(Example 2)
The ink receiving layer of the recording medium 1 is composed of 3% by mass of Adekastab 522A (trade name, manufactured by Asahi Denka Kogyo Co., Ltd.), a phosphite compound that is liquid at room temperature, and a hindered amine compound that is solid at room temperature. The same procedure as in Example 1 was performed except that a MIBK solution containing 1.5% by mass of ADK STAB LA-63P (trade name, manufactured by Asahi Denka Kogyo Co., Ltd.) was coated with a bar coater.

Example 3
The ink receiving layer of the recording medium 1 has 3% by mass of Adekastab 522A (trade name, manufactured by Asahi Denka Kogyo Co., Ltd.), which is a phosphite compound that is liquid at room temperature, and a hindered amine compound that is liquid at room temperature. The same procedure as in Example 1 was performed except that a MIBK solution containing 1.5% by mass of ADK STAB LA62 (trade name, manufactured by Asahi Denka Kogyo Co., Ltd.) was coated with a bar coater.

Example 4
The ink receiving layer of the recording medium 1 is made of 3% by mass of Adekastab AO-80 (trade name, manufactured by Asahi Denka Kogyo Co., Ltd.), which is a hindered phenol compound that is solid at room temperature, and a hindered amine compound that is liquid at room temperature. The same procedure as in Example 1 was performed except that a MIBK solution containing 1.5% by mass of ADK STAB LA62 (trade name, manufactured by Asahi Denka Kogyo Co., Ltd.) was coated with a bar coater.

(Example 5)
The ink-receiving layer of the recording medium 1 has 3% by mass of Adeka Stub 1500 (trade name, manufactured by Asahi Denka Kogyo Co., Ltd.), which is a phosphite compound that is liquid at normal temperature, and a hindered amine compound that is liquid at normal temperature. The same procedure as in Example 1 was performed except that a MIBK solution containing 1.5% by mass of ADK STAB LA62 (trade name, manufactured by Asahi Denka Kogyo Co., Ltd.) was coated with a bar coater.

(Comparative Example 1)
A MIBK solution containing 4.5 mass of ADK STAB LA-63P (trade name, manufactured by Asahi Denka Kogyo Co., Ltd.), a hindered amine compound that is solid at room temperature, was applied to the ink receiving layer of the recording medium 1 with a bar coater. Except for this, the same procedure as in Example 1 was performed.

  The transparency of the ink receiving layer of the recording medium for ink jet produced in Examples 1 to 5 and Comparative Example 1 was measured by measuring the total transmittance (%) with Nippon Denka Kogyo / Haze Meter NHD-1001DP (trade name). did. The results are shown in Table 1.

(Example 6)
First, the base material was produced as follows.

Cationized starch 0.60 was added to a pulp slurry consisting of 80 parts by mass of hardwood bleached kraft pulp (LBKP) having a freeness of 450 ml CSF (Canadian Standardrad Freeness) and 20 parts by weight of softwood bleached kraft pulp (NBKP) having a freeness of 480 ml CSF. After adding parts by weight, 10 parts by weight of heavy calcium carbonate, 15 parts by weight of light calcium carbonate, 0.10 parts by weight of alkyl ketene dimer and 0.03 parts by weight of cationic polyacrylamide, the stock is adjusted, and then the long net papermaking The paper was made by a machine, subjected to a three-stage wet press, and dried with a multi-cylinder dryer. After that, impregnated with an oxidized starch aqueous solution to a solid content of 1.0 g / m ² with a size press machine, dried and machine calendered, basis weight 155 g / m ² , Steecht size 100 seconds, A base material having an air permeability of 50 seconds, a Beck smoothness of 30 seconds, and a Gurley stiffness of 11.0 mN was obtained.

  Next, alumina hydrate was prepared.

Aluminum dodexide was prepared by the method described in US Pat. No. 4,242,271. Next, by the method described in US Pat. No. 4,420,870, the aluminum dodexide was hydrolyzed to produce an alumina slurry. Water was added to the alumina slurry until the solid content of alumina hydrate was 12% by mass. The pH of the alumina slurry was 9.9. Then, 5 mass% nitric acid aqueous solution was added and pH was adjusted to 7. This was aged at 105 ° C. for 3.5 hours to obtain alumina hydrate. The alumina hydrate had a BET specific surface area of 168 m ² / g.

  First, after the alumina hydrate was dispersed in ion-exchanged water, an aqueous solution of ion-exchanged water in which polyvinyl alcohol / Gosenol NH-18 (trade name, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) was dissolved was added. At this time, weighed, added, mixed and stirred so that the solid content mass of alumina hydrate / polyvinyl alcohol solid content mass (pigment / binder) was 9/1, and dispersed to obtain a coating solution. .

Next, a 5% by mass aqueous borax solution heated to 30 ° C. is applied to the surface of the substrate to make it wet, and then these coating solutions are applied onto the substrate using an extrusion type coater head. The coating was simultaneously performed so that the coating amount was 32 g / m ² and dried in an oven at 100 ° C. for 5 minutes. A recording medium 2 was obtained. The recording medium 2 obtained did not have any powder falling or cracking.

Next, 2.25% by mass of Adekastab 522A (trade name, manufactured by Asahi Denka Kogyo Co., Ltd.), which is a phosphite compound that is liquid at room temperature, and a hindered amine compound that is solid at room temperature are provided on the ink-receiving layer provided. A MIBK solution containing 2.25% by mass of a certain ADK STAB LA-63P (trade name, manufactured by Asahi Denka Kogyo Co., Ltd.) is applied every 1.3 g / m ² using an extrusion type coater head. The coating was performed at 60 m / min. And it dried at 120 degreeC and obtained the target recording medium for inkjet.

(Example 7)
The ink receiving layer of the recording medium 2 is composed of 3% by mass of Adekastab 522A (trade name, manufactured by Asahi Denka Kogyo Co., Ltd.), which is a phosphite compound that is liquid at room temperature, and a hindered amine compound that is solid at room temperature. The same procedure as in Example 6 was performed except that a MIBK solution containing 1.5% by mass of ADK STAB LA-63P (trade name, manufactured by Asahi Denka Kogyo Co., Ltd.) was coated with an extrusion type coater head.

(Example 8)
3% by mass of Adekastab 522A (trade name, manufactured by Asahi Denka Kogyo Co., Ltd.), which is a phosphite ester compound that is liquid at room temperature, and a hindered amine compound that is liquid at room temperature are used for the ink receiving layer of the recording medium 2. The same procedure as in Example 6 was performed except that a MIBK solution containing 1.5% by mass of ADK STAB LA62 (trade name, manufactured by Asahi Denka Kogyo Co., Ltd.) was coated with an extrusion type coater head.

  When the image density and the fastness of the recorded image were evaluated on the inkjet recording media obtained in Examples 6 to 8 by the following evaluation methods, the results shown in Table 2 were obtained.

[Evaluation methods]
<Image robustness of recorded matter>
Production of recorded matter: using a photo printer (trade name: PIXUS 950i, manufactured by Canon) using an inkjet method, black, cyan, and black on the recording surface of the inkjet recording medium produced in Examples 6 to 8 above. A recorded matter on which a solid batch of 100% Duty of magenta and yellow was printed was prepared. This recorded material was used for the following tests.

(Ozone resistance test)
The above recorded matter was subjected to a gas exposure resistance test using an ozone exposure tester (manufactured by Suga Test Instruments Co., Ltd., trade name: OMS-HS).
・ Test condition ozone concentration: 2.0ppm
Test time: 1.5 hours Temperature and humidity conditions in test layer: 23 ° C., 60% RH
The evaluation method of ozone resistance is to measure the above-mentioned recorded matter before and after the test using a spectrophotometer / spectrino (made by Gretag Macbeth Co.), and obtain ΔE (movement distance in Lab color space) from the following equation: Judgment was made based on the criteria described below.

ΔE = {(L value of recorded material before test−L value of recorded material after test) ² + (a value of recorded material before test−a value of recorded material after test) ² + (record before test) B value of the product-b value of the recorded material after the test) ² } ^1/2
Judgment standard (circle): The thing with the largest (DELTA) E among 4 color solid batches is less than 10.
Δ: The value of the one with the largest ΔE among the four color solid batches is 10 or more.

<Fluorescent lamp test>
A fluorescent lamp exposure test was performed on the recorded matter using a fluorescent lamp tester (trade name: FT-1 manufactured by Suga Test Instruments Co., Ltd.).
Test condition Fluorescent light intensity: 80000 Lux
Test time: 600 hours Temperature and humidity conditions in the test layer: 30 ° C., 60% RH
The fluorescent lamp resistance evaluation method is to measure the image density of the above recorded matter before and after the test using a spectrophotometer / spectrino (manufactured by Gretag Macbeth Co., Ltd.) and obtain the concentration residual rate from the following formula. Judgment was made based on the criteria described.

Density remaining rate (%) = image density after test / image density before test × 100
Judgment Criteria A: M density residual ratio is 85% or more, and no change in color tone is observed in recorded matter before and after the test.
○: M density remaining rate is 75% or more and less than 85%, and the color tone of the recorded matter after the test is slightly changed compared to the recorded matter before the test.
Δ: M concentration remaining rate is less than 75%, and the recorded matter after the test clearly has a different color tone than the recorded matter before the test.

<Image density>
Using a photo printer (trade name: PIXUS 950i, manufactured by Canon Inc.) using an ink jet method, the recording surface of the ink jet recording medium manufactured in Examples 6 to 8 above is a monochrome 3 cm square of black. A recorded matter having 100% printed portions was produced. The image density of 100% printed portion of black of this recorded matter was measured using a spectrophotometer / Spectrino (manufactured by Gretag Macbeth).
A: O.I. D is 2.1 or higher.
○: O.D. D is 1.9 or more and less than 2.1.
Δ: O.D. D is less than 1.9.

As described above, according to the present invention, it is possible to provide an ink jet recording medium having long-term image storage stability and clear image characteristics.

Claims (5)

  Inkjet recording comprising: a base material; and a pigment formed on the base material for holding a colorant of ink, a binder for binding the pigment, and an ink receiving layer containing a colorant deterioration preventing component In the medium, the ink composition includes at least two compatible color material deterioration preventing materials as the color material deterioration preventing component, and at least one of the color material deterioration preventing materials is liquid at room temperature. Recording media for use.   The inkjet recording medium according to claim 1, wherein the coloring material deterioration preventing component includes at least one coloring material deterioration preventing material that is solid at room temperature.   The colorant deterioration preventing component includes at least two selected from the group consisting of hindered amine compounds, hindered phenol compounds, phosphite compounds, thiuram compounds, and thioether compounds. 3. A recording medium for inkjet according to 1 or 2.   The inkjet recording medium according to claim 3, wherein the coloring material deterioration preventing component includes at least a hindered amine compound. The inkjet recording medium according to claim 2, comprising a hindered amine compound as the colorant deterioration preventing material that is solid at room temperature.