JP4459174B2 - Ink-receiving layer forming composition and substrate for printing - Google Patents

Description

  The present invention relates to a composition for forming an ink receiving layer capable of printing character information and image information by an ink jet method. The present invention also relates to a substrate to be printed having an ink receiving layer formed using the composition for forming an ink receiving layer.

  In recent years, CD-type and DVD-type optical recording media capable of writing and reading information with a laser have begun to spread widely. Companies dealing with a small amount of various types of optical recording media are required to be able to print images and characters representing the recording contents of the optical recording media by the inkjet method. Furthermore, as the use of optical recording media has spread to general users, printers capable of printing on such recording media have been released, and the label side of the disc (the side opposite to the optical writing / reading side) has been released. For the purpose of designing the surface), there is an increasing demand for printing not only characters representing recorded contents but also high-quality images such as photographs.

  Against this background, many optical recording media having a label surface that can be printed by an ink jet printer have been sold. Since the ink used in the ink jet system is usually an aqueous ink, an ink receiving layer having water absorption is formed on the surface of the label surface. As the coating composition for forming the ink receiving layer, radiation curable compositions such as ultraviolet rays are often used from the viewpoint of productivity.

  The ink receiving layer is required to have image storability such as quick drying of an ink used in an ink jet method, sharpness of an image, and water resistance. As a coating composition for realizing such a requirement, Patent Document 1 includes a coating composition that promotes ink absorption and improves resolution by providing an uneven structure on the surface of a hydrophilic ink-receiving layer.

  In addition, a coating composition has been proposed that improves quick drying and sharpness of images by adding an inorganic filler or an organic filler to a hydrophilic resin. Patent Document 2 includes a coating composition containing a porous smectite as an inorganic filler.

  Further, Patent Document 3 includes a coating composition containing porous alumina as an inorganic filler. As the organic filler, Patent Document 4 includes a coating composition containing water-absorbing resin particles. Patent Document 5 includes a coating composition using a natural material as the organic filler.

Many coating compositions containing organic cations have also been proposed in order to improve the water resistance of the ink receiving layer. An acid dye is usually used for an ink jet ink. For this reason, it is an attempt to fix dye molecules having opposite charges by adding an organic cation to the ink receiving layer. As a specific example, Patent Document 6 is cited.
JP-A-6-60432 Japanese Patent Laid-Open No. 7-272441 Japanese Patent Laid-Open No. 11-213445 JP 7-169100 A JP-A-10-259340 Japanese Patent Laid-Open No. 2001-311022

  However, in the ink-receiving layer to which the above inorganic filler or organic filler is added, it may be difficult to achieve both image drying characteristics, image sharpness, and water storability characteristics such as water resistance. In addition, when a porous inorganic filler is mixed in the resin, the resin penetrates into the pores of the filler, so that sufficient water absorption is not obtained and drying properties are deteriorated. In some cases, bleeding is likely to occur. Further, when an organic filler having high water absorption is used, the ink absorbability is improved, but on the other hand, the drying property and the water resistance tend to be inferior. Therefore, there is a demand for an ink-receiving layer that is further improved in quick drying properties, image sharpness, and water resistance.

  An object of the present invention is to provide a composition for forming an ink receiving layer capable of forming an ink receiving layer excellent in image storability such as quick drying, image sharpness, and water resistance.

  Another object of the present invention is to provide a substrate to be printed having an ink receiving layer formed using the above-described composition for forming an ink receiving layer.

The ink receiving layer forming composition of the present invention comprises:
(A) a monomer component containing a monofunctional monomer;
(B) a powder containing an egg white component containing 5% by weight or more of basic protein in the solid content of egg white component;
(C) eggshell powder.

  The ink-receiving layer-forming composition of the present invention can further take the following aspects.

  In the composition for forming an ink receiving layer of the present invention, the component (A) can further contain a bifunctional or higher functional monomer.

  In the composition for forming an ink receiving layer of the present invention, the basic protein of the component (B) can be lysozyme or / and a salt thereof.

  In the composition for forming an ink receiving layer of the present invention, the component (B) may be one in which the surface of inorganic particles or organic particles is covered with an egg white component containing a basic protein.

  In the composition for forming an ink receiving layer of the present invention, the average particle size of the component (B) may be 0.01 to 30 μm.

  In the composition for forming an ink receiving layer of the present invention, the average particle size of the component (C) may be 0.01 to 30 μm.

  In the composition for forming an ink receiving layer of the present invention, the sum of the contents of the component (B) and the component (C) is 5 to 200 parts by weight with respect to 100 parts by weight of the component (A). be able to.

  In the composition for forming an ink receiving layer of the present invention, the ratio of the content of the component (B) and the component (C) (content of the component (B) / content of the component (C)) is: It can be 1/10 to 10.

In the composition for forming an ink receiving layer of the present invention, the component (A) further contains a polymerization initiator,
Content of the said polymerization initiator can be 0.01-10 weight part with respect to 100 weight part of the said (A) component.

  The ink receiving layer forming composition of the present invention can be cured by radiation.

The substrate to be printed of the present invention comprises a supporting substrate,
An ink receiving layer formed on the support substrate using the above-described ink receiving layer forming composition.

  In the substrate to be printed according to the present invention, the ink receiving layer may be formed by forming a coating film on the support substrate and curing the coating film with radiation.

  The substrate to be printed of the present invention can be printed by an inkjet method.

  In the substrate to be printed of the present invention, the support substrate may be an optical recording medium on which at least one of writing and reading is optically performed.

  According to the composition for forming an ink-receiving layer of the present invention, an ink-receiving layer provided on a printing surface of a substrate on which printing is performed by an ink jet method, such as quick drying, image sharpness, and water resistance. An ink receiving layer having excellent storage stability can be formed. The egg white component containing the basic protein (B) in the composition for forming an ink-receiving layer of the present invention is a water-soluble protein, and therefore has water absorption and has an amino group in its molecule. For this reason, it is possible to improve the adhesion of ink. On the other hand, the eggshell powder as component (C) also has water absorption because it is a porous body, and contains organic substances such as protein. Binding or affinity can be increased.

  Moreover, the tendency of the affinity differs between the component (B) and the component (C) depending on the kind of the acid dye. For example, the component (B) is particularly excellent in fixing property to cyan and yellow dyes, and the component (C) is particularly excellent in fixing property to magenta dyes. As a result, it is possible to obtain an ink receiving layer forming composition having excellent image sharpness by including both the component (B) and the component (C). Furthermore, the improvement of the ink fixing property can suppress the deterioration of the image with time (such as bleeding caused by absorbing moisture in the atmosphere). That is, according to the present invention, it is possible to provide a composition capable of forming an ink receiving layer excellent in image storage stability such as quick drying, image sharpness, and water resistance.

  An example of the embodiment of the present invention will be described below.

  The composition for forming an ink receiving layer of the present invention comprises (A) a monomer component containing a monofunctional monomer, (B) a powder containing an egg white component, and (C) an eggshell powder.

  First, the component (A) will be described.

  The component (A) contains at least a monofunctional monomer. Examples of the monofunctional monomer include N-vinylpyrrolidone, N-acryloylmorpholine, N-vinylformamide, N, N-dimethylacrylamide, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2- Hydroxy-3-phenoxypropyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, butanediol monoacrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, N, N-diethylaminoethyl acrylate, N, Mention of monomers such as N-dimethylaminoethyl (meth) acrylate and 2-hydroxyethyl vinyl ether, and methoxy-polyethylene glycol mono (meth) acrylate Can. Mixtures of these monomers can also be used.

  Further, N-vinylacetamide, N-hydroxymethylacrylamide as monomers that are solid at room temperature, and trimethyl-2- (acryloyloxy) ethylammonium chloride, trimethyl-3- () as monomers having a quaternary ammonium salt in the side chain. Mention may be made of acryloyloxy) propylammonium chloride, trimethyl-2-hydroxy-3- (acryloyloxy) propylammonium chloride, trimethyl-2- (acryloylamino) ethylammonium chloride, trimethyl-2- (acryloylamino) propylammonium chloride. it can. These solid monomers can also be used by dissolving in the liquid monomer.

  The component (A) of the present invention may further contain a bifunctional or higher polyfunctional monomer.

  Although it does not specifically limit as a polyfunctional monomer, For example, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, polyethyleneglycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol Tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate , Neopentyl glycol di (meth) acrylate, 1,6 hexanediol di (meth) acrylate, bisphenol A di (meth) acrylate, Cyanuric acid trihydroxyethyl di (meth) acrylate, isocyanuric acid trihydroxyethyl tri (meth) acrylate, ethylene oxide modified product or propylene oxide modified product of these compounds, (poly) ethylene glycol di (meth) acrylate, (poly ) Propylene glycol di (meth) acrylate, various urethane acrylates, epoxy acrylates, polyester acrylates and the like. Mixtures of these monomers can also be used.

  The polyfunctional monomer serves as a cross-linking agent and can be used for controlling coating film hardness, coating water absorption and water resistance.

  In the monomer component (A), when both a monofunctional monomer and a polyfunctional monomer are used, the monofunctional monomer is 70 to 99% by weight, and the bifunctional or higher polyfunctional monomer is 1 to 30% by weight. Preferably there is. More preferably, the monofunctional monomer is 80 to 98% by weight and the polyfunctional monomer is 2 to 20% by weight.

  When the polyfunctional monomer is less than 1% by weight, problems may occur in the curability of the composition and the strength of the coating film, and sufficient water resistance may not be obtained. On the other hand, if it exceeds 30% by weight, the printability tends to be lowered due to a decrease in water absorption of the resulting cured film. Further, the substrate may be warped or the adhesiveness may be reduced due to curing shrinkage.

  In consideration of applying the component (A) to the support substrate, the component (A) is preferably liquid. In this case, a monomer that is liquid per se or a solution obtained by dissolving a solid monomer in a liquid monomer can be used. Further, when thermosetting is used as a curing method, a monomer component obtained by dissolving a solid monomer in a known organic solvent may be used.

  Next, the component (B) will be described.

  The component (B) is a powder containing an egg white component containing a basic protein. In the present invention, the egg white component refers to an egg white liquid dried to a moisture content of 20% or less. The raw egg white liquor is the one in which the shelled egg is broken and the yolk is removed, the frozen egg white is thawed, hydrolyzed by enzyme treatment, desalted, and lysozyme. Those obtained by removing the components, those obtained by chemically modifying egg white protein with fatty acids or saccharides, those obtained by desugaring with enzymes, yeasts, bacteria, or the like can be used. Note that the egg white component may contain some other contaminants other than the egg white component such as the egg yolk component.

  In the present invention, the basic protein refers to a protein having an isoelectric point of 9 or more when the protein is isolated and purified with high purity.

  Examples of basic proteins include lysozyme, avidin, protamine, lactoperoxidase, trypsinogen, chymotrypsinogen, α-chymotrypsin, aldolase, cytochrome C, ribonuclease, milk basic protein, histone and the like. Basic peptides such as polylysine can also be included.

The basic protein is preferably egg white lysozyme and / or a salt thereof.
Examples of lysozyme salts include salts of inorganic acids or organic acids such as carbonates, phosphates, hexametaphosphates, sulfates, glutamates, glyceroline trumpet salts, and gluconates in addition to hydrochlorides. In particular, hydrochloride, that is, lysozyme chloride is preferable.

  The egg white component containing basic protein used in the present invention is not only a method of adding egg white lysozyme having a purity in the egg white component or a basic protein such as a salt thereof, but also egg white lysozyme in egg white by various methods. Or a method for increasing the content of a basic protein such as a salt thereof. The content of the basic protein is 5% by weight or more, preferably 10% by weight or more, more preferably 20% by weight or more of the solid content of the egg white component. It is because the effect mentioned later cannot fully be exhibited as it is less than 5 weight%.

  As a method for increasing the content of egg white lysozyme or a salt thereof in the egg white component, a general method for purifying egg white lysozyme or a salt thereof can be used.

The purification method of lysozyme is, for example,
a) a method in which impurities are removed many times with an aqueous salt solution or water during the washing operation after contacting the weakly acidic cation exchange resin with lysozyme adsorbed on the resin;
b) Elution of lysozyme adsorbed on weakly acidic cation exchange resin with saline solution or buffer solution
c) a method of repeating the operation of bringing the aqueous solution containing the eluted lysozyme into contact with a weakly acidic cation exchange resin;
d) A method of devising pH, concentration, stirring conditions, cooling conditions, etc. when adding a seed crystal after elution and salting out,
e) A method of repeating the salt folding operation multiple times,
f) A method in which lysozyme crystals are dissolved in water and pulp, cotton, or other adsorbent is added while controlling the pH, and impurities are adsorbed on this adsorbent.
g) It is achieved by permeating through a porous hollow fiber membrane having a weakly acidic cation exchange resin and appropriately combining methods for separating lysozyme.

  As the component (B), the egg white component whose content is increased by purifying the basic protein by the above method, or the egg white component whose content is increased by adding the basic protein of a certain purity, these are concentrated and dried. Particles can be used. Further, the basic protein having a certain purity and the egg white component can be separately concentrated and dried to mix the particles. Furthermore, the particle | grains which covered the surface of the other particle | grains with the egg white component containing the basic protein obtained in this way can be used.

  As a method for concentrating and drying egg white components, known methods are used, and examples thereof include conventional methods such as spray drying, freeze drying, and shallow plate drying. Moreover, after drying, the dried product may be pulverized as necessary. You may use what was stored for the purpose of sterilization after drying. In addition, the egg white component can be recovered by re-precipitation of a shell egg with egg yolk removed and a frozen egg white thawed in a water-soluble organic solvent such as alcohol or acetone.

  As particles having the surface of other particles covered with an egg white component containing a basic protein, particles obtained by coating the surface of another organic filler or an inorganic filler with an egg white component can be used. Thus, the following can be mentioned as an advantage in coating the surface of another organic filler or an inorganic filler with the egg white component containing a basic protein. The component (B) preferably has an average particle size in a desired range (see the description below). However, in a general production method of dried egg white particles, it may be necessary to spend cost and time when controlling the particle size with high accuracy. In such a case, if the surface of another organic filler or inorganic filler is covered with an egg white component containing a basic protein, particles having an average particle size controlled more efficiently can be obtained. And the fixing property of a dye can also be ensured by the egg white component containing the basic protein which covers the surface.

  The coating on the surface of other fillers is a mixture of other fillers and those obtained by breaking the shell eggs and removing the yolks, those obtained by thawing frozen egg whites, or those obtained by re-dissolving the dried egg whites in water. And drying can be carried out easily.

  As described above, the surface of the egg white component containing a basic protein is coated with organic fillers such as cellulose and silk protein, titanium oxide, zinc oxide, silica, alumina, calcium carbonate, calcium sulfate, synthetic Mention may be made of inorganic fillers such as mica.

  Next, the eggshell powder as component (C) will be described.

  Eggshell powder is obtained by pulverizing avian eggs, particularly white chicken eggs (white balls). Specifically, eggshells such as chicken eggs are washed and coarsely pulverized, and the eggshell membranes are removed, followed by dehydration drying and fine pulverization. Examples of the grinding method for obtaining the eggshell powder include a hammer mill, a ball mill, a jet mill, a turbo mill, and a pin mill.

  Moreover, as eggshell powder, various commercially available eggshell powders and those obtained by baking these at high temperatures can also be used. If the egg is not white, it can be decolorized using a bleaching agent such as oxidized chlorine, oxidized oxygen, or reduced after pulverization.

The eggshell powder in the present invention preferably has high whiteness. What is whiteness here?
It is a value obtained by the following equation (1) using a Hunter-type colorimetric color difference meter.

W (whiteness) = 100 − [(100−L) ² + (a ² + b ² )] ^1/2 (1)
(In the above formula, L is lightness, a is hue, and b is saturation.)
It is preferable that the whiteness measured with this white meter is 80 degrees or more. Further, the whiteness is preferably 90 degrees or more. This is because when the colored eggshell powder is used, the appearance of the ink receiving layer is impaired and the color tone of the printed image is adversely affected.

  The eggshell powder which is the component (C) of the present invention has a specific surface area in the range of 1.5 to 5.0 when measured by BET multipoint specific surface area measurement. This is because calcium carbonate, which is the main component of eggshell powder, is a porous body. Regarding the bulk specific gravity, A.I. B. When measured with a D powder characteristic measuring instrument (manufactured by Tsutsui Rikenki Co., Ltd.), it is in the range of 0.8 to 1.3.

  The sum of the contents of the component (B) and the component (C) is preferably 5 to 200 parts by weight with respect to 100 parts by weight of the component (A). More preferably, it is 20-100 weight part. When the addition amount is less than 5 parts by weight, the image sharpness and water resistance tend to be insufficient. On the other hand, when it exceeds 200 parts by weight, the drying property tends to decrease. Furthermore, coatability may be reduced.

  Moreover, as for the ratio of each content of (B) component and (C) component, it is preferable that the value of content of (B) component / content of (C) component is 1 / 10-10. When the ratio of the component (B) and the component (C) is outside the range of 1/10 to 10, the synergistic effect obtained by using both cannot be sufficiently exhibited.

  Both the average particle diameters of the component (B) and the component (C) are preferably 0.01 to 30 μm. More preferable average particle diameters of (B) and (C) are 0.05 to 20 μm. When the average particle size is 0.01 μm, the water absorption tends to decrease, and the drying property and image sharpness may decrease. On the other hand, if it exceeds 30 μm, the smoothness of the coating film is deteriorated, the appearance is deteriorated, and the image sharpness may be lowered.

  Here, the average particle diameter is a particle diameter calculated by irradiating a particle group with laser light and obtaining a particle size distribution by calculation from an intensity distribution pattern of diffracted / scattered light emitted therefrom. As a measuring apparatus for measuring the average particle diameter by this method, for example, a laser diffraction particle size distribution measuring apparatus SALD2000A (manufactured by Shimadzu Corporation) can be mentioned.

  The composition for forming an ink receiving layer of the present invention may contain a polymerization inhibitor, a leveling agent, an antifoaming agent, a dispersant, a resin other than the monomer, and the like as necessary. Also, other inorganic fillers such as titanium oxide, zinc oxide, silica, alumina, calcium carbonate, calcium sulfate, synthetic mica and other fine particles, organic fillers such as cellulose resin particles such as methylcellulose, and polyvinyl alcohol resin particles are hydrophilic. The fine particles may be contained to such an extent that the object of the present invention is not impaired.

  The composition for forming an ink receiving layer is used in combination with a photopolymerization initiator that generates radicals upon irradiation when ultraviolet rays or visible rays are used as radiation during curing. The photopolymerization initiator is not particularly limited, and may be appropriately selected from ordinary ones such as acetophenone, benzoin, benzophenone, and thioxanthone. Specifically, 2-hydroxy-2-methylpropiophenone, 1-hydroxycyclohexyl phenyl ketone, benzoin, benzoin methyl ether, benzoin isopropyl ether, benzophenone, methyl o-henzoylbenzoate, 2,4-diethylthioxanthone, 4,4-bisdiethylaminobenzophenone, 2,2-diethoxyacetophene, 2-chlorothioxanthone, diisopropylthioxanthone, 9,10-anthraquinone, 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2- Examples include methyl-propiophenone, 4-isopropyl-2-hydroxy-2-methylpropiophenone, α, α-dimethoxy-α-phenylacetone. In addition, you may use a some compound together as a photoinitiator.

  A photoinitiator can use 0.01-10 weight part with respect to 100 weight part of (A) component, Preferably 0.5-8 weight part can be used. When the content of the photopolymerization initiator is less than 0.01 parts by weight with respect to 100 parts by weight of the component (A), curing may be insufficient, the coating film may become sticky, Bleeding may occur. Moreover, when it exceeds 10 weight part, yellowing and coloring of a coating film may be seen.

  As an ultraviolet ray source for irradiating the coating film, a normal one such as a metal halide lamp or a mercury lamp can be used.

  According to the composition for forming an ink-receiving layer of the present invention, an ink-receiving layer provided on a printing surface of a substrate on which printing is performed by an ink jet method, such as quick drying, image sharpness, and water resistance. An ink receiving layer having excellent storage stability can be formed. The egg white component containing a basic protein of the component (B) of the composition for forming an ink receiving layer of the present invention is a water-soluble protein, and therefore has water absorption, and has an amino group in its molecule. Therefore, the fixing property of the ink can be improved. On the other hand, the eggshell powder as component (C) also has water absorption because it is a porous body, and contains organic substances such as protein. Binding or affinity can be increased.

  Moreover, the tendency of the affinity differs between the component (B) and the component (C) depending on the kind of the acid dye. For example, the component (B) is particularly excellent in fixing property to cyan and yellow dyes, and the component (C) is particularly excellent in fixing property to magenta dyes. As a result, it is possible to obtain an ink receiving layer forming composition having excellent image sharpness by including both the component (B) and the component (C). Furthermore, the improvement of the ink fixing property can suppress the deterioration of the image with time (such as bleeding caused by absorbing moisture in the atmosphere). That is, according to the present invention, it is possible to provide a composition capable of forming an ink receiving layer excellent in image storage stability such as quick drying, image sharpness, and water resistance.

  The substrate to be printed of the present invention has a supporting substrate and an ink receiving layer formed on the supporting substrate using the above-described ink receiving layer forming composition. This ink receiving layer is a layer formed using the above-described composition for forming an ink receiving layer.

  Examples of the supporting base material include paper and plastic base materials such as polyester resin, polycarbonate resin, acrylic resin, and cellulose resin.

  The ink receiving layer is formed by supporting the ink receiving layer forming composition by a known printing method such as screen printing, gravure printing, flexographic printing, or a coating method such as spin coating, dip coating, bar coating, or roll coating. After being applied to the film, it is cured by irradiation with radiation. As the radiation for curing, an electron beam, ultraviolet light, visible light, or the like can be used. The thickness of the ink receiving layer thus formed is desirably 5 to 100 μm, more preferably about 10 to 30 μm.

  The substrate to be printed of the present invention has an ink receiving layer suitable for the ink jet system. As described above, since this ink receiving layer is excellent in image characteristics such as quick drying and image sharpness, it can be suitably used for various applications. In particular, when the supporting base material is an optical recording medium, a general user can write characters and photographs representing the recorded contents for the purpose of designing the disc label surface (the surface opposite to the optical writing / reading surface). It is possible to provide an optical recording medium in response to a request for printing such a high-quality image. When the substrate to be printed is an optical recording medium, the optical recording medium is a coating-type recording layer mainly composed of a dye on a disk-shaped substrate formed of various transparent thermoplastic resins such as polycarbonate resin. The reflective layer and the protective film are provided in this order, and an ink receiving layer made of a radiation cured product of the coating composition of the present invention is provided on the protective film.

[Example]
Examples of the present invention will be described below. The present invention is not limited to the following examples, and can be modified within the scope of the gist of the present invention.

  In Example 1, dry egg white particles and egg white lysozyme powder particles were mixed as the component (B) in the following ratio and pulverized by a jet mill. Dry egg white particles: egg white lysozyme = 95: 5 (lysozyme content 7.8%), 80:20 (lysozyme content 22.2%), 50:50 (lysozyme content 51.0%), 5:95 ( Four types of mixing ratio particles having a lysozyme content of 94.2% were prepared, and were sequentially designated as Examples 1-1, 1-2, 1-3, and 1-4. As the dried egg white particles, dry egg white K type manufactured by QP Corporation was used, and as the egg white lysozyme, egg white lysozyme (purity: 99%) manufactured by QP Corporation was used. The average particle diameter of the obtained particles was 7 μm. The average particle size was measured with a laser diffraction particle size distribution analyzer SALD2000A (manufactured by Shimadzu Corporation) (the same applies hereinafter).

  As the component (C), commercially available eggshell powder (egg calcium No. 11, manufactured by QP Corporation) was used. The average particle size of the eggshell powder was 4 μm. The specific surface area was 3.3, and the whiteness was 93.8 degrees. The specific surface area is a value measured using a high-precision fully automatic gas adsorption device BELSORP 36 (manufactured by Nippon Bell Co., Ltd.), and the whiteness is a colorimetric color difference meter ZE2000 (manufactured by Nippon Denshoku Industries Co., Ltd.). It is the value measured using.

  The composition for forming an ink receiving layer according to Example 1 was prepared by mixing the component (B), the component (C), and each compound at the ratio shown in Table 1 below, and stirring the mixture with a stirrer. Obtained.

  Then, an application layer was formed on the 125 μm-thick biaxially stretched polyester film by the bar coating method using the ink receiving layer forming composition. Immediately thereafter, ultraviolet rays were irradiated using a metal halide lamp and cured to form an ink receiving layer having a thickness of 20 μm.

  In Example 2, the same components as in Example 1-1 were used for both the component (B) and the component (C). The composition for forming an ink receiving layer according to Example 2 was obtained by mixing the respective compounds at the ratio shown in Table 1 below and stirring with a stirrer.

  Next, an ink receiving layer was formed in the same manner as in Example 1 using this ink receiving layer forming composition. The obtained ink receiving layer had a thickness of 22 μm.

  In Example 3, as the component (B), a filler composed of an egg white component that has been subjected to a hydrophobic treatment was used. First, 25 g of dried egg white used in Example 1 was dissolved in 225 ml of water. Next, this was dripped at 1000 ml of acetone. Thereby, the generated precipitate was collected by filtration. Then, it was dried at 40 ° C. This was mixed 1: 1 with lysozyme chloride fine powder (purity 99.5%). The average particle diameter of the obtained particles (hereinafter referred to as “reprecipitation egg white / lysozyme chloride mixed particles”) was 0.6 μm. As the component (C), the same component as in Example 1 was used.

  The composition for forming an ink receiving layer according to Example 3 was obtained by mixing each compound at a ratio shown in Table 1 below and stirring with a stirrer.

  Next, an ink receiving layer was formed in the same manner as in Example 1 using this ink receiving layer forming composition. The obtained ink receiving layer had a thickness of 21 μm.

  In Example 4, silica gel, which is an inorganic filler, was coated with an avidin-containing egg white component as component (B). The component (B) was adjusted as follows. First, 25 g of dried egg white and 5 g of avidin (purity 99%) were dissolved in 225 ml of water. Next, 25 g of Sirisia 350 (Fuji Silysia Chemical Co., Ltd.) was added and stirred. Thereafter, water is distilled off by filtration, and the recovered filtrate is heated and dried at 40 ° C. to coat the surface with avidin-containing egg white components, which is referred to as “Silkia 350” (hereinafter referred to as “egg white / avidin coated particles”). ) The average particle diameter of the obtained particles was 2.4 μm. As the component (C), the same component as in Example 1 was used.

  The ink receiving layer forming composition according to Example 4 was obtained by mixing the compounds shown in Table 1 below and stirring with a stirrer.

  Next, an ink receiving layer was formed in the same manner as in Example 1 using the ink receiving layer forming composition. The obtained ink receiving layer had a thickness of 21 μm.

  In Example 5, the same components as in Example 1-1 were used as the component (B) and the component (C). The ink receiving layer forming composition according to Example 5 was obtained by mixing the compounds shown in Table 1 below and stirring with a stirrer.

  Next, an ink receiving layer was formed in the same manner as in Example 1 using the ink receiving layer forming composition. The obtained ink receiving layer had a thickness of 20 μm.

[Comparative Examples 1 to 7]
In Comparative Examples 1 to 5, instead of the egg white component having an increased basic protein content in Examples 1 to 5, it was replaced with a simple egg white component, and each compound was blended at a weight ratio shown in Table 1 below. The composition for forming an ink receiving layer according to Comparative Examples 1 to 5 was obtained by stirring with a stirrer. That is, Comparative Examples 1, 2, and 5 are the egg white components that do not use egg white lysozyme in Examples 1, 2, and 5, respectively, and Comparative Example 3 is the reprecipitation egg white particles that do not use lysozyme chloride in Example 3. 4 used the egg white coating particle which does not use avidin in Example 4. Furthermore, a composition for forming an ink receiving layer without using the component (B) was obtained as Comparative Example 6, and a composition for forming an ink receiving layer without using any of the components (B) and (C) was obtained as Comparative Example 7.

Next, using the ink receiving layer forming compositions according to Comparative Examples 1 to 7, ink receiving layers were formed in the same manner as in Example 1. The thickness of the ink receiving layer obtained was 20 μm for Comparative Example 1, 22 μm for Comparative Example 2, 21 μm for Comparative Example 3, 21 μm for Comparative Example 4, 20 μm for Comparative Example 5, 23 μm for Comparative Example 6, and Comparative Example 7 Was 21 μm.

(Evaluation)
Printing is performed on the ink receiving layer obtained in the above-described Examples and Comparative Examples using an inkjet printer PM-G700 (manufactured by Seiko Epson Corporation), and ink drying, image sharpness, and water resistance are evaluated according to the following evaluation methods. Sex was evaluated. The results are shown in Table 1.

Ink drying property: Paper was pressed against the printing surface of an ink jet printer, and the time until the ink was not transferred to the paper was measured and judged according to the following criteria.
○: Drying time is within 30 seconds.
Δ: Drying time from 30 seconds to 2 minutes.
X: Drying time is 2 minutes or more.

Image clarity: The image printed surface was observed visually and using an optical microscope (magnification: 100 times), and judged according to the following criteria.
○: The image is clear and clear.
Δ: Some blur is observed in the image.
X: The image is smudged severely or repels ink.

Water resistance (resistance to deterioration of image quality over time); after storage at 60 ° C and 90% for 24 hours, change of image is observed visually and using an optical microscope (magnification: 100x), and judged according to the following criteria did.
A: There is no change before and after storage at high temperature and high humidity, and image clarity is maintained.
○: The change before and after storage at high temperature and high humidity is small, and the image definition is maintained.
Δ: Color tone change and bleeding are observed in the image.
X: The ink flows and the image is noticeably blurred.

  As is clear from Table 1, in Examples 1 to 5, it was confirmed that an ink receiving layer having excellent ink quick drying properties and image sharpness could be formed as compared with Comparative Examples 1 to 5. Further, it was confirmed that the water resistance was excellent as compared with Comparative Example 6.

Claims (14)

(A) a monomer component containing a monofunctional monomer;
(B) a powder containing an egg white component containing 5% by weight or more of basic protein in the solid content of egg white component;
(C) eggshell powder;
A composition for forming an ink-receiving layer. In claim 1,
The component (A) is a composition for forming an ink receiving layer, further comprising a bifunctional or higher monomer. In claim 1 or 2,
The composition for forming an ink receiving layer, wherein the basic protein of the component (B) is lysozyme or / and a salt thereof. In claim 1 or 2,
The component (B) is an ink-receiving layer forming composition in which the surface of inorganic particles or organic particles is covered with an egg white component containing a basic protein. In any of claims 1 to 4,
The composition for forming an ink receiving layer, wherein the component (B) has an average particle size of 0.01 to 30 μm. In any of claims 1 to 5,
The ink receiving layer forming composition, wherein the component (C) has an average particle size of 0.01 to 30 μm. In any one of Claims 1 thru | or 6.
The sum of the content of the component (B) and the component (C) is an ink receiving layer forming composition that is 5 to 200 parts by weight with respect to 100 parts by weight of the component (A). In any one of Claims 1 thru | or 7,
The ratio of the content of the component (B) and the component (C) (the content of the component (B) / the content of the component (C)) is 1/10 to 10, and the ink receiving layer is formed. Composition. In any of claims 1 to 8,
The component (A) further contains a polymerization initiator,
The composition for forming an ink receiving layer, wherein the content of the polymerization initiator is 0.01 to 10 parts by weight with respect to 100 parts by weight of the component (A). In any one of Claim 1 thru | or 9,
A composition for forming an ink receiving layer, which is cured by radiation. A support substrate;
An ink receiving layer formed using the ink receiving layer forming composition according to any one of claims 1 to 10 on the support substrate. In claim 11,
The ink receiving layer is a substrate to be printed on which a coating film is formed on the supporting substrate and the coating film is cured by radiation. In either of claims 11 or 12,
A substrate to be printed, which is printed by an inkjet method. In any one of claims 11 to 13,
The substrate to be printed is a substrate to be printed, which is an optical recording medium on which at least one of writing and reading is optically performed.