JP2006172588A - Optical recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical recording medium which has a swelling type ink receiving layer having excellent ink absorptivity and wherein a printed image having excellent glossiness and scratch resistance, and high image quality wherein bleeding and bronzing are not conspicuous can be obtained by a printing system such as an ink jet system. <P>SOLUTION: In the optical recording medium having at least an optical recording layer 2 and the ink receiving layer 5 on a light transmissive substrate 1, the ink receiving layer 5 contains ≥50 wt.% water soluble polymer and further contains at least one selected from the group consisting of a urea derivative, an aromatic carboxylic acid and its salt. The ink receiving layer 5 may further contain a cyclic amide compound. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical recording medium that records and reproduces information using laser light, and to an optical recording medium capable of image printing by an inkjet method or the like on the surface.

  An optical recording medium is a means for storing various information such as audio data and image data in addition to computer information, and is a write-once type (CD-R) capable of recording and reproducing information, and can be erased after information is recorded. Rewriting type (CD-RW) has been developed and is widely used. In recent years, with the increase in the amount of information handled, DVD-R (recordable type) and DVD-RW (rewritable type), which are optical recording media having a larger capacity than CD-R and CD-RW, have begun to spread. .

  It is desirable for users of the above optical recording medium to be able to understand at a glance what information is recorded on the optical recording medium. Conventionally, information contents in an optical recording medium can be discriminated by displaying the recorded contents directly on the surface of the optical recording medium using a writing instrument, or by sticking a sticker displaying characters and images. However, recently, a method of printing directly on the surface of an optical recording medium using an inkjet printer, which is widely used by personal computer users, has been used. An optical recording medium having an ink-receiving layer capable of being developed has been developed. As such an optical recording medium, for example, an optical recording medium (see Patent Document 1) in which the outermost layer of the protective layer is made of a binder resin having a porous structure on the surface, a light absorbing layer, a light reflecting layer on a transparent substrate, An optical recording medium in which a protective layer and / or a print receiving layer are sequentially laminated, and the outermost protective layer or the print receiving layer includes a polyvinyl acetal resin, a water-dispersible resin, and / or a water-soluble resin (see Patent Document 2) An optical recording medium comprising at least a recording layer, a metal reflective layer, a white-printed protective layer, and a hydrophilic surface layer containing a water-absorbing and / or oil-absorbing filler on a transparent substrate (Patent Document) 3).

Optical recording media that can be printed by the inkjet method as described above are roughly classified into an absorption type (also called a porous type or a void type) and a swelling type depending on the configuration of the ink receiving layer. The absorption type ink receiving layer contains a pigment such as silica and a binder for binding the pigment as essential components. The layer has innumerable fine pores, and the landed ink contains the pores. Is absorbed inside the layer. On the other hand, the swelling type ink receiving layer is mainly composed of a water-soluble polymer such as gelatin, and the ink receiving layer swells and is colored by the moisture of the landed ink.
Japanese Patent Laid-Open No. 11-213445 JP-A-8-161769 Japanese Patent Laid-Open No. 10-188344

The swelling type ink receiving layer has a problem in ink absorbability and has an adverse effect on print quality. In other words, the swelling type ink receiving layer has a long time from ink landing to drying and fixing, so that bleeding occurs where the color is blurred or mixed unevenly at the boundary of different colors, or the ink is Since the ink receiving layer is dried before it completely penetrates into the ink receiving layer, there is a problem that the gloss which is originally obtained cannot be obtained or the printed image is peeled off by slight friction. In addition, since the swelling type ink receiving layer is difficult to absorb ink, in a high density region such as a solid printing portion, the coloring material is likely to be deposited and aggregated on the upper surface of the ink receiving layer, which causes a so-called bronze phenomenon. There is also a problem that it is easy. The bronze phenomenon disturbs the color balance of the entire image, causes variations in glossiness, and causes a decrease in print quality.
Various problems due to the low ink absorbability as described above can be avoided by a method of reducing the amount of ink applied, but this method leads to a decrease in color developability of the printed image.

  Accordingly, an object of the present invention is to have a swelling type ink receiving layer excellent in ink absorbability, excellent in glossiness and abrasion resistance by a printing method such as an ink jet method, and high in image quality with no noticeable bleeding or bronze. An object of the present invention is to provide an optical recording medium from which a printed image can be obtained.

  The present invention relates to an optical recording medium having at least an optical recording layer and an ink receiving layer on a translucent substrate, wherein the ink receiving layer contains 50% by weight or more of a water-soluble polymer, and contains a urea derivative and an aromatic carboxyl. The object described above is achieved by providing an optical recording medium comprising one or more selected from the group consisting of acids and salts thereof.

  The optical recording medium of the present invention has a so-called swelling type since the ink absorbability of the ink receiving layer is sufficiently enhanced by one or more selected from the group consisting of the above urea derivatives and aromatic carboxylic acids and salts thereof. Compared to conventional optical recording media having an ink-receiving layer, it is excellent in gloss and abrasion resistance, can provide high-quality printed images that are inconspicuous in bleed and bronze, and has a high-definition silver salt photographic tone. An image can be obtained.

The optical recording medium of the present invention will be described below based on a preferred embodiment with reference to the drawings.
The optical recording medium of this embodiment is a so-called CD-R type optical disc, and has at least an optical recording layer and an ink receiving layer on a donut-shaped disc-shaped translucent substrate having a clamp hole at the center.

  Specifically, as shown in FIG. 1, in the optical recording medium of the present embodiment, a tracking guide groove 1a is formed in a spiral shape on a translucent substrate 1, and an optical recording medium is formed on the guide groove 1a. The recording layer 2, the light reflecting layer 3, the protective layer 4 and the ink receiving layer 5 are sequentially laminated. This optical recording medium corresponds to a method of recording and reproducing information by irradiating laser light from the side of the light transmissive substrate 1, and the ink receiving layer 5 is irradiated with the laser light of the light transmissive substrate 1. It is formed in the outermost layer opposite to the side.

  As the material for forming the translucent substrate 1, those used as substrates for this type of optical disk can be used without any particular limitation. For example, polycarbonate, polymethyl methacrylate, polystyrene resin, vinyl chloride resin, epoxy Examples thereof include plastics such as resins, and glass.

  Examples of the optical recording layer 2 include a thin film containing a dye, an inorganic compound thin film made of a metal such as Te, a magneto-optical recording alloy thin film made of FeTbCo, a phase change recording alloy thin film such as GeSbTe, AgInSbTe, or SnSbSe. Can be mentioned. Among these, in particular, an optical recording layer containing a dye can be easily manufactured and can have a high recording density, and is preferably used in the present invention. Examples of the dye include cyanine dyes, polymethine dyes, porphyrin dyes, phthalocyanine dyes, azo dyes, naphthoquinone dyes, naphthalocyanine dyes, squarylium dyes, metal complex dyes, and the like. One kind can be used alone or two or more kinds can be used in combination. The optical recording layer having a dye can be formed by, for example, spin coating by dissolving the dye in a suitable solvent, or by vapor deposition by heating the dye under reduced pressure. The optical recording layer containing a dye can contain an ultraviolet curing agent, a light stabilizer and the like for the purpose of improving the stability of the dye in addition to a polymer, a decomposition accelerator, and the like.

  The light reflecting layer 3 can be formed by vapor deposition, sputtering, ion plating, or the like of a metal or an alloy material such as Au, Ag, Cu, Ni, Pt, etc., like the light reflecting layer in this type of optical disk. it can.

  The protective layer 4 is a layer for physically and chemically protecting the optical recording layer 2 and the light reflecting layer 3. Examples of the material for forming the protective layer 4 include an ultraviolet curable resin, a thermosetting resin, and a thermoplastic resin. The protective layer 4 can be formed by a known spin coating method using these forming materials.

  The above-described configuration of the optical recording medium of the present embodiment is the same as that of a conventionally known optical recording medium.

  Hereinafter, the ink receiving layer 5 will be described in detail. This ink-receiving layer is a so-called swelling type (non-absorbing type, non-porous) ink-receiving layer, and the water-soluble polymer is added in an amount of 50% by weight or more based on the total solid weight of the ink-receiving layer, preferably 70 to 98% by weight is contained.

  Examples of the water-soluble polymer include vinyl formals such as gelatins, polyvinyl alcohols, polyvinyl pyrrolidones, polyvinyl pyridinium halides, various modified polyvinyl alcohols and derivatives thereof (Japanese Patent Laid-Open Nos. 60-145879 and 60-220750). 61-143177, 61-235182, 61-235183, 61-237681, 61-26189), polyalkylene oxides, polyacrylamide, polydimethylacrylamide, polydimethylaminoacrylate, Polymers containing acrylic groups such as polyacrylic acid soda, acrylic acid / methacrylic acid copolymer salt, polymethacrylic acid soda, vinyl acrylate / vinyl alcohol copolymer salt (Japanese Patent Laid-Open Nos. 60-168651 and 62-9) 88), natural polymers such as starch, oxidized starch, carboxyl starch, dialdehyde starch, cationized starch, dextrin, sodium alginate, gum arabic, casein, pullulan, dextran, methylcellulose, ethylcellulose, carboxymethylcellulose, hydroxypropylcellulose or the like Derivatives thereof (see JP-A Nos. 59-174382, 60-262585, 61-143177, 61-181679, 61-193879, 61-287882), polyethylene glycol, polypropylene glycol, polyvinyl Synthesis of ether, polyglycerin, alkyl vinyl ether maleate copolymer, N-vinyl pyrrole maleate copolymer, styrene maleic anhydride copolymer, polyethyleneimine, etc. Rimmer (JP 61-32787, DoAkira 61-237680 Patent, No. DoAkira 61-277483 reference), and the like. In the present invention, one of these may be used alone, or two or more may be used in combination.

  Among these water-soluble polymers, gelatins, polyvinyl alcohols, polyvinyl pyrrolidones, cellulose derivatives and acrylic derivatives are particularly preferably used in the present invention.

  As the gelatin used in the present invention, any gelatin can be used as long as it is made from animal collagen, but gelatin made from collagen made from pig skin, cowhide, or cow bone is preferred. The type of gelatin is not particularly limited, but lime-processed gelatin, acid-processed gelatin, and gelatin derivatives (for example, Japanese Patent Publication Nos. 38-4854, 39-5514, 40-12237, and 42-26345). U.S. Pat.Nos. 2,525,753, 2,594,293, 2,614,928, 2,763,639, 3,118,766, 3,132,945, 3,186,843, 3,332,553, British Patents 861,414, 1031189 etc.) can be used alone or in combination.

  The ink receiving layer contains, as an essential component, one or more selected from the group consisting of urea derivatives and aromatic carboxylic acids and salts thereof together with the water-soluble polymer. That is, the ink receiving layer contains at least one of urea derivatives, aromatic carboxylic acids, and salts of aromatic carboxylic acids.

  Examples of the urea derivative include urea, allyl urea, dimethylol urea, malonyl urea, carbamyl urea, n-butyl urea, dibutyl urea, N, N-dimethyl urea, 1,3-dimethyl urea, N-methyl urea, hydroxy Urea, ethylurea, methylurea, creatinine, 2-imidazolidinone, benzylurea, (R)-(+)-1-phenylethylurea, phenylurea, 3-hydroxyphenylurea, 1-phenylsemicarbazide, 4-phenyl Semicarbazide, N-benzoylurea, N, N′-O-phenyleneurea and the like can be mentioned, and one of these can be used alone or in combination of two or more. Among these, a urea derivative having a phenyl group (in the above, benzylurea to N, N′-O-phenyleneurea corresponds to a urea derivative having a phenyl group) is preferable.

  When the urea derivative is contained in the ink receiving layer, the content thereof is preferably 0.2 to 20% by weight, more preferably 0.5 to 15% by weight based on the total solid weight of the ink receiving layer. %, More preferably 0.5 to 10% by weight. If the content of the urea derivative is less than 0.2% by weight, the significance of addition (improved ink absorbency and print quality) is poor, and conversely if it exceeds 20% by weight, the haze (transparency) of the ink receiving layer decreases. There is a risk that sufficient color development of the printed image cannot be ensured.

  The aromatic carboxylic acid and salt thereof may be any aromatic compound and salt thereof having at least one carboxyl group in the molecular structure, such as 2-hydroxy-1-naphthoic acid, 1-hydroxy 2-naphthoic acid, 1-naphthoic acid, 2-naphthoic acid, 3-hydroxy-2-naphthoic acid, 6-hydroxy-2-naphthoic acid, 3-methoxy-2-naphthoic acid, 6-methoxy-2-naphthoic acid Examples include acids, 6-ethoxy-2-naphthoic acid, 6-propoxy-2-naphthoic acid, 4-hydroxybenzoic acid, 2,6-naphthalenedicarboxylic acid, and salts thereof (for example, lithium salts).

  As said aromatic carboxylic acid and its salt, the aromatic compound and its salt which have one carboxyl group in molecular structure are preferable, and the compound and its salt which have a naphthalene skeleton are preferable. Those having an —OR group (R is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms) together with a carboxyl group in the naphthalene skeleton can also be preferably used in the present invention. In the compound having a naphthalene skeleton and a salt thereof, the carboxyl group , —OR groups are preferably one each.

  The compound having a naphthalene skeleton and a salt thereof are preferably a compound having a carboxyl group at the 2-position of the naphthalene skeleton and a salt thereof, more preferably an alkali of a compound having a carboxyl group at the 2-position of the naphthalene skeleton. It is a metal salt. Among the alkali metal salts, lithium salts, that is, lithium salts of compounds having a carboxyl group at the 2-position of the naphthalene skeleton are particularly preferable from the viewpoint of improving ink permeability and improving bronzing resistance.

  Examples of the compound having a carboxyl group at the 2-position of the naphthalene skeleton include 1-hydroxy-2-naphthoic acid, 2-naphthoic acid, 3-hydroxy-2-naphthoic acid, 6-hydroxy-2-naphthoic acid, Examples include 3-methoxy-2-naphthoic acid, 6-methoxy-2-naphthoic acid, 6-ethoxy-2-naphthoic acid, and 6-propoxy-2-naphthoic acid.

  The salt of the aromatic compound having a carboxyl group described above can be added in the form of a salt and contained in the ink-receiving layer. Also, the aromatic compound having a carboxyl group and the base are separately provided. It can be added and contained in the ink receiving layer.

  When the above-mentioned aromatic carboxylic acid or a salt thereof or both of them is contained in the ink receiving layer, the content thereof (the content of the aromatic carboxylic acid and / or the salt thereof) is the total solid weight of the ink receiving layer. The content is preferably 0.2 to 10% by weight, more preferably 0.5 to 7% by weight, and still more preferably 0.5 to 5% by weight. If the content of the aromatic carboxylic acid and / or salt thereof is less than 0.2% by weight, the meaning of addition (improved ink absorbency and print quality) is poor, and conversely if it exceeds 10% by weight, the haze of the ink receiving layer (Transparency) decreases, and there is a possibility that sufficient color development of a printed image cannot be ensured.

  In addition, the ink receiving layer has at least one selected from the group consisting of the above-described urea derivatives and aromatic carboxylic acids and salts thereof from the viewpoint of further improving ink absorbability (hereinafter also referred to as urea derivatives). In addition, it is preferable to further contain a cyclic amide compound. Examples of the cyclic amide compound include nicotinamide, 6-aminonicotinamide, N, N-diethylnicotinamide, N-ethylnicotinamide, N-methylpyrrolidone, 5-methyl-2-pyrrolidone, 5-hydroxymethyl- Examples include 2-pyrrolidone, δ-valerolactam, ε-caprolactam, heptlactam, pyroglutamic acid, N-methyl-ε-caprolactam, and the like can be used alone or in combination of two or more.

  The content ratio of the urea derivative or the like and the cyclic amide compound in the ink receiving layer is (urea derivative or the like) :( cyclic amide compound) = 1 from the viewpoint of improving ink absorbency and maintaining transparency. : It is preferable that it exists in the range of 3-5: 1, More preferably, it is 1: 2-4: 1, More preferably, it is 1: 1-3: 1.

  The ink receiving layer may contain a hardening agent (crosslinking agent) for the purpose of improving water resistance and dot reproducibility. Examples of the hardener include aldehyde compounds such as formaldehyde and glutaraldehyde, ketone compounds such as diacetyl and chloropentanedione, bis (2-chloroethylurea) -2-hydroxy-4,6-dichloro-1,3, 5-triazine, a compound having a reactive halogen as described in US Pat. No. 3,288,775, a divinylsulfone, a compound having a reactive olefin as described in US Pat. No. 3,635,718, and an N-methylol compound as described in US Pat. No. 2,732,316 , Isocyanates as described in U.S. Pat. No. 3,103,437, aziridine compounds as described in U.S. Pat. Nos. 3,017,280 and 2983611, carbodiimide compounds as described in U.S. Pat. No. 3,100,704, and As There are epoxy compounds, halogen carboxaldehydes such as mucochloric acid, dioxane derivatives such as dihydroxydioxane, chromium alum, potash alum, zirconium derivatives such as zirconium sulfate and ammonium zirconium carbonate, etc., one or more of these They can be used in combination. The content of the hardener is preferably 0.01 g to 10 g, more preferably 0.1 to 5 g with respect to 100 g of the water-soluble monomer in the ink receiving layer.

  The ink receiving layer may contain a surfactant for the purpose of improving dot reproducibility and improving image quality. As the surfactant, anionic, cationic, nonionic, and betaine-based surfactants are preferably used, and low-molecular or high-molecular surfactants may be used. In particular, a fluorosurfactant is preferable. The content of the surfactant is preferably 0.001 to 5 g, more preferably 0.01 to 3 g with respect to 100 g of the water-soluble monomer in the ink receiving layer.

  The ink receiving layer may contain fine particles having an average particle size of 1 μm or less for the purpose of preventing so-called blocking. The average particle diameter of the fine particles is preferably 0.2 μm or less, more preferably 0.02 μm or less from the viewpoint of gloss. The fine particles may be inorganic fine particles or organic fine particles, but in the case of organic fine particles, the glass transition temperature or film forming temperature is preferably 50 ° C. or higher and 300 ° C. or lower. The content of the fine particles is preferably 1 to 35% by weight, more preferably 10 to 30% by weight, based on the total solid content weight of the ink receiving layer.

  In addition to the above-described hardener (crosslinking agent), surfactant, and organic or inorganic fine particles, the ink receiving layer includes a coloring dye, a coloring pigment, an ultraviolet absorber, an antioxidant, a pigment dispersant, an anti-foaming agent. Various known additives such as foaming agents, leveling agents, preservatives, optical brighteners, viscosity stabilizers, pH adjusters and the like can be contained.

  The ink receiving layer can be formed by applying a coating solution containing the various components by a known coating method. In addition, after coating a coating solution containing various components other than the urea derivative and the cyclic amide compound to form a coating layer, the urea derivative and the cyclic amide are added to the coating layer. It can also be formed by applying a compound obtained by dissolving a compound in an appropriate solvent such as alcohol.

  The thickness of the ink receiving layer is preferably 10 to 40 μm from the viewpoint of ensuring ink absorbability.

  The surface of the ink receiving layer desirably has high gloss, and specifically, the 20 degree gloss specified by JIS-Z8741 is preferably 15% or more.

The optical recording medium of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, the optical recording medium of the present invention only needs to have at least an optical recording layer and an ink receiving layer, the other layer types, and the total number of layers in the optical recording medium including the optical recording layer and the ink receiving layer. The order of stacking the layers is not limited to the above-described embodiment, and can be changed as appropriate.
Further, the optical recording medium of the present invention includes a CD-type read-only optical disc (CD-ROM), a rewritable CD-RW type optical disc, a DVD-type read-only optical disc, The present invention can also be applied to optical disks such as recordable DVD-RAM and -RW. Further, the form of the optical disk itself is not limited to the above-mentioned donut disk shape.

  Hereinafter, the present invention will be described more specifically with reference to examples of the present invention and test examples showing the effects of the present invention. However, the present invention is not limited to the examples.

[Example 1]
A donut-shaped disk-shaped polycarbonate translucent substrate having a tracking guide groove having a width of 0.5 μm and a depth of 35 nm, a diameter of 120 mm, and a thickness of 1.2 mm was molded. A methyl cellosolve solution (concentration of 2.4% by weight) of a metal-containing azo dye was applied onto this translucent substrate by spin coating, and then dried in a dryer at 80 ° C. for 10 minutes to form an optical recording layer. did. On this optical recording layer, a gold film having an average thickness of 100 nm was formed by a DC magnetron sputtering method in an argon gas to obtain a light reflecting layer. An ultraviolet curable polyurethane resin (trade name SD-318, manufactured by Dainippon Ink & Chemicals, Inc.) is applied onto the light reflecting layer by a spin coating method, and then cured by irradiating with ultraviolet rays to provide a protective layer having a thickness of 6 μm. A layer was formed.
On the protective layer, the ink receiving layer coating liquid 1 having the following composition was applied and dried using a bar coater so that the thickness after drying was 22 μm to form an ink receiving layer. The optical recording medium thus obtained was used as a sample of Example 1. The 20 degree glossiness defined by JIS-Z8741 on the surface of the ink receiving layer of this optical recording medium was 36%.

<Ink-receiving layer coating solution 1>
Gelatin (Konica Gelatin KV-3000): 39% by weight
Polyvinyl pyrrolidone (BASF PVP-K90): 45% by weight
・ Carboxymethylcellulose sodium (CMC1205 manufactured by Daicel Chemical Industries): 10% by weight
-Zirconium ammonium carbonate (Japan Light Metal AZC): 1% by weight
・ Urea: 5% by weight

[Example 2]
In Example 1, an optical recording medium was produced in the same manner as in Example 1 except that the ink receiving layer coating liquid 2 having the following composition was used in place of the ink receiving layer coating liquid 1. A sample of Example 2 was obtained. The 20 degree glossiness defined by JIS-Z8741 on the surface of the ink receiving layer of this optical recording medium was 38%.
<Ink-receiving layer coating solution 2>
Gelatin (Konica Gelatin KV-3000): 39.1% by weight
Polyvinyl pyrrolidone (BASF PVP-K90): 45% by weight
・ Carboxymethylcellulose sodium (CMC1205 manufactured by Daicel Chemical Industries): 10% by weight
-Zirconium ammonium carbonate (Japan Light Metal AZC): 1% by weight
2-naphthoic acid: 4% by weight
-Lithium hydroxide monohydrate: 0.9% by weight

Example 3
In Example 1, an optical recording medium was produced in the same manner as in Example 1 except that the ink receiving layer coating liquid 3 having the following composition was used instead of the ink receiving layer coating liquid 1. A sample of Example 3 was obtained. The 20 degree glossiness defined by JIS-Z8741 on the surface of the ink receiving layer of this optical recording medium was 29%.
<Ink-receiving layer coating solution 3>
Gelatin (Konica Gelatin KV-3000): 30% by weight
Polyvinyl pyrrolidone (BASF PVP-K90): 50% by weight
・ Carboxymethylcellulose sodium (CMC1205 manufactured by Daicel Chemical Industries): 10% by weight
-Zirconium ammonium carbonate (Japan Light Metal AZC): 1% by weight
・ Urea: 5% by weight
2-pyrrolidone: 4% by weight

Example 4
In Example 1, an optical recording medium was produced in the same manner as in Example 1 except that the ink receiving layer coating liquid 4 having the following composition was used in place of the ink receiving layer coating liquid 1. A sample of Example 4 was obtained. The 20 degree glossiness defined by JIS-Z8741 on the surface of the ink receiving layer of this optical recording medium was 41%.
<Ink-receiving layer coating solution 4>
Gelatin (Konica Gelatin KV-3000): 40% by weight
Polyvinylpyrrolidone (BASF PVP-K90): 39.55% by weight
・ Carboxymethylcellulose sodium (CMC1205 manufactured by Daicel Chemical Industries): 10% by weight
-Zirconium ammonium carbonate (Japan Light Metal AZC): 1% by weight
・ Urea: 4% by weight
2-pyrrolidone: 3% by weight
2-naphthoic acid: 2% by weight
-Lithium hydroxide monohydrate: 0.45% by weight

Example 5
In Example 1, an optical recording medium was produced in the same manner as in Example 1 except that the ink receiving layer coating liquid 5 having the following composition was used in place of the ink receiving layer coating liquid 1. A sample of Example 5 was obtained. The 20 degree glossiness defined by JIS-Z8741 on the surface of the ink receiving layer of this optical recording medium was 39%.
<Ink-receiving layer coating solution 5>
Gelatin (Konica Gelatin KV-3000): 40% by weight
Polyvinylpyrrolidone (BASF PVP-K90): 39.55% by weight
・ Carboxymethylcellulose sodium (CMC1205 manufactured by Daicel Chemical Industries): 10% by weight
-Zirconium ammonium carbonate (Japan Light Metal AZC): 1% by weight
・ Benzylurea: 4% by weight
2-pyrrolidone: 3% by weight
2-naphthoic acid: 2% by weight
-Lithium hydroxide monohydrate: 0.45% by weight

[Comparative Example]
In Example 1, an optical recording medium was produced in the same manner as in Example 1 except that the ink receiving layer coating liquid 6 having the following composition was used in place of the ink receiving layer coating liquid 1. A sample for comparison was used. The 20 degree glossiness defined by JIS-Z8741 on the surface of the ink receiving layer of this optical recording medium was 41%.
<Ink-Receptive Layer Coating Liquid 6>
Gelatin (Konica Gelatin KV-3000): 39% by weight
Polyvinyl pyrrolidone (BASF PVP-K90): 50% by weight
・ Carboxymethylcellulose sodium (CMC1205 manufactured by Daicel Chemical Industries): 10% by weight
-Zirconium ammonium carbonate (Japan Light Metal AZC): 1% by weight

[Test example]
Each sample (optical recording medium) was evaluated for image quality, gloss, bronze resistance, and abrasion resistance by the following methods. The evaluation results are shown in [Table 1] below.

(Image quality evaluation method)
The above sample is set in an ink-jet printer PM-G800 manufactured by Seiko Epson, and a high-definition color digital standard image [(ISO / JIS-SCID), image name “portrait” is formed with an aqueous dye ink on the surface of the ink receiving layer of the sample. "(Sample number 1, image recognition number N1)" was printed in "recommended clean mode". The printed surface of the printed material thus produced is visually observed, and A (good image quality) is seen where there is no bleed (a phenomenon in which colors bleed or mix unevenly at the boundary of different colors), and the bleed is slightly seen. And B was conspicuous.

(Glossiness evaluation method)
The sample is set in the inkjet printer PM-G800, and a color patch is formed by ejecting cyan ink (water-based dye cyan ink, which is standardly installed in PM-G800) on the surface of the ink receiving layer of the sample at a duty of 100%. Printed. This color patch is visually observed, and A (good gloss) is not inferior in gloss to the glossy surface of the silver salt photograph, and partially glossy in comparison to the glossy surface of the silver salt photograph. Although there were some inferior parts, B was generally good glossiness, and C was generally matte (matte) tone or gloss unevenness.

(Bronze resistance evaluation method)
The sample was set in the ink jet printer PM-G800, and color patches obtained by shaking the cyan ink in 10% increments from 10% to 100% duty were printed on the surface of the ink receiving layer of the sample. The printed matter thus prepared was left in an environment of room temperature 23 ° C. and humidity 50% RH for 24 hours, and then the printing state (presence or absence of bronzing) of each color patch was visually observed and evaluated according to the following evaluation criteria. The bronze phenomenon is a phenomenon frequently observed in inks that use metal phthalocyanine dyes as the colorant, and it appears red in areas printed with high duty such as solid printing (100% duty fill printing). This means that a phenomenon (under white fluorescent lamps, white reflected light originally has a red to pink hue) is observed.
Evaluation criteria A: Bronze phenomenon cannot be confirmed in all color patches having a duty of 10% to 100%. Good bronze resistance.
B: The occurrence of bronzing can be confirmed with a color patch with a duty of 70% or more, but the occurrence of bronzing cannot be confirmed with a color patch with a duty of 60% or less.
C: The occurrence of bronzing can be confirmed with a color patch having a duty of 60% or less.

(Rubbing resistance evaluation method)
The sample was set in the ink jet printer PM-G800, and the color ink was printed on the surface of the ink receiving layer of the sample by discharging the cyan ink at a duty of 100% to produce a printed matter. Then, after rubbing the color patch of this printed matter with the belly of the finger, the state is visually observed. A color material that does not come off from the color patch is A (good abrasion resistance), and some color material is missing. B was confirmed, and C was clearly observed to be removed from the coloring material.

It is sectional drawing which shows typically the cross section of CD-R as one Embodiment of the optical recording medium of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Translucent substrate, 2 ... Optical recording layer, 3 ... Light reflection layer, 4 ... Protective layer, 5 ... Ink receiving layer

Claims (14)

In an optical recording medium having at least an optical recording layer and an ink receiving layer on a translucent substrate,
The optical recording medium, wherein the ink receiving layer contains 50% by weight or more of a water-soluble polymer and contains at least one selected from the group consisting of urea derivatives, aromatic carboxylic acids and salts thereof.   2. The optical recording medium according to claim 1, wherein the urea derivative is a urea derivative having a phenyl group.   3. The optical recording medium according to claim 1, wherein the aromatic carboxylic acid and a salt thereof are an aromatic compound having one carboxyl group and a salt thereof.   4. The optical recording medium according to claim 3, wherein the aromatic compound having one carboxyl group and a salt thereof are a compound having a naphthalene skeleton and a salt thereof.   5. The optical recording medium according to claim 4, wherein the compound having a naphthalene skeleton and a salt thereof are a compound having a carboxyl group at the 2-position of the naphthalene skeleton and a salt thereof.   The compounds having a carboxyl group at the 2-position of the naphthalene skeleton and salts thereof are 1-hydroxy-2-naphthoic acid, 2-naphthoic acid, 3-hydroxy-2-naphthoic acid, 6-hydroxy-2-naphthoic acid, 3 6. Methoxy-2-naphthoic acid, 6-methoxy-2-naphthoic acid, 6-ethoxy-2-naphthoic acid, 6-propoxy-2-naphthoic acid and salts thereof Optical recording medium.   The optical recording medium according to claim 6, wherein the salt is a lithium salt.   8. The optical recording medium according to claim 1, wherein the content of the urea derivative is 0.2 to 20% by weight.   The optical recording medium according to any one of claims 1 to 8, wherein the content of the aromatic carboxylic acid and / or a salt thereof is 0.2 to 10% by weight.   The optical recording medium according to claim 1, wherein the ink receiving layer further contains a cyclic amide compound.   The cyclic amide compounds are nicotinamide, 6-aminonicotinamide, N, N-diethylnicotinamide, N-ethylnicotinamide, N-methylpyrrolidone, 5-methyl-2-pyrrolidone, 5-hydroxymethyl-2-pyrrolidone The optical recording medium according to claim 10, wherein the optical recording medium is at least one selected from the group consisting of δ-valerolactam, ε-caprolactam, heptactam, pyroglutamic acid, and N-methyl-ε-caprolactam.   The content ratio of one or more selected from the group consisting of the urea derivative and the aromatic carboxylic acid and salt thereof (hereinafter referred to as urea derivative) in the ink receiving layer and the cyclic amide compound is (urea derivative etc. 12. The optical recording medium according to claim 10, wherein: (cyclic amide compound) = 1: 3 to 5: 1.   13. The light according to claim 1, wherein the water-soluble polymer is at least one selected from the group consisting of gelatins, polyvinyl alcohols, polyvinyl pyrrolidones, cellulose derivatives and acrylic derivatives. recoding media. The optical recording medium according to any one of claims 1 to 13, wherein the 20-degree glossiness defined by JIS-Z8741 on the surface of the ink receiving layer is 15% or more.