JP3059377B2 - Recording substrate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording substrate used in an ink jet recording system.

[0002]

2. Description of the Related Art The use of various water-soluble inks that do not use organic solvents as much as possible is increasing due to an increase in environmental problems. In particular, writing on many substrates has been studied with the development of the ink jet recording system. The ink used in the ink jet recording system usually contains a water-soluble dye such as an acid dye or a direct dye, and water as a main component, and often contains a small amount of a polyhydric alcohol in many cases.

As a substrate to be used in the ink jet recording system, a substrate having a hydrophilic surface such as ordinary paper or special paper for ink jet having a porous ink receiving layer is conventionally used. In many cases, a recording layer is provided on the surface of the substrate. Examples of such materials include starch, gelatin, casein, gum arabic, sodium alginate, carboxymethylcellulose, polyvinyl alcohol, polyvinylpyrrolidone, and a water-soluble polymer layer such as sodium polyacrylate; 2. Description of the Related Art A synthetic resin latex such as a rubber latex, and an organic solvent-soluble resin layer such as polyvinyl butyral and polyvinyl chloride are provided.
Further, it has been proposed to use a polymer having a cationic ion. Since water-soluble dyes for ink-jet often have anions such as sulfonic acid, it can be said that they are expected to prevent re-elution of ink by ionic bonding. Examples of such a cationic polymer include polyvinyl alcohol having a quaternary ammonium base,
Polymers such as polyacrylic acid esters and polyacrylic acid amides are known (Japanese Unexamined Patent Publication (Kokai) No. 61-228984, and others). Also, use of polyethylene glycol dicarboxylic acid has been proposed to improve color (Japanese Patent Publication No. 4-1706).

Since these water-soluble polymers have a very strong hydrophilic property, when a hydrophilic substance such as paper is used as the substrate, the water-soluble polymer easily conforms to the substrate, and the recording layer is formed on the surface of the substrate using these polymers. When providing, there is no problem in adhesion and the like. However, for a substrate having a strongly hydrophobic surface, such as an ultraviolet curable resin, which is often used for a protective film of an optical recording medium or the like, since it lacks adhesiveness, it may be easily peeled off after being provided, Furthermore, the water resistance of the recording layer itself is low, and after printing, bleeding of the ink due to water droplets and the like are large, and there is a problem in practicality. Further, there is a problem that the hardness of the recording layer is not sufficient.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to obtain an adhesiveness and water resistance, such as being obtained in a single coating step, having excellent quick-drying properties, and having no delamination of a print or the whole layer even when wiped after being wetted with water. To provide a recording substrate having a recording surface layer having excellent printing stability, sufficient surface hardness, excellent color printability, and writable with an ink containing a water-soluble dye. It is.

[0006]

This and other objects are achieved by the present invention which is defined below as (1) to (10). (1) A compound having a quaternary ammonium base having three alkyl groups and a carboxylic acid having a recording surface layer writable with an ink containing a water-soluble dye on a substrate, wherein the recording surface layer has three alkyl groups. A recording substrate, which is obtained by radiation-curing a coating film containing a compound having a group, and wherein the compound having a quaternary ammonium base is a monomer represented by the following chemical formula (3) or (4).

[0007]

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[0008]

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[In each of Chemical Formulas 3 and 4, R
⁰ represents a hydrogen atom or a methyl group. R ¹ , R ² and R ³ each represent an alkyl group, and the total number of carbon atoms of these three alkyl groups is 4 or more. L ¹ is ^one of an oxy group (—O—) and a carbonyl group (—CO—)
It represents an alkylene group having 1 to 8 carbon atoms which may be interposed by more than one kind, and ^one of R ¹ , R ² and R ³ is an alkyl group having 3 to 10 carbon atoms. X ^- represents a halide ion. (2) The recording substrate according to (1), wherein the compound having a carboxylic acid group is at least one of (meth) acrylic acid and a derivative thereof. (3) The recording substrate according to the above (1) or (2), wherein the curing is ultraviolet curing. (4) The recording substrate according to any one of (1) to (3), wherein the coating further contains a compound having a hydroxyl group. (5) The recording substrate according to any one of (1) to (4), wherein the coating film further contains a compound having a morpholino group. (6) The recording substrate according to any one of (1) to (5), wherein the recording surface layer further contains porous particles. (7) The recording substrate according to any one of (1) to (6), wherein the writing is performed by an inkjet recording method. (8) The recording substrate according to any one of (1) to (7), wherein the substrate is an optical recording medium having a radiation-curable protective film. (9) The recording substrate according to any one of the above (1) to (8), wherein the substrate is an optical recording medium having an ultraviolet curing protective film. (10) The optical recording medium has a reflective layer in close contact with the recording layer, and has at least one protective film including the protective film on the reflective layer. The recording substrate according to the above (8) or (9), wherein at least one of the layers contains a white pigment.

[0010]

In the recording substrate of the present invention, the coating film for forming the recording surface layer contains a compound having a quaternary ammonium group having three alkyl groups and a compound having a carboxylic acid group. In this case, at least one of these compounds is a monomer having a terminal ethylenically unsaturated reactive group. Further, in the compound having a quaternary ammonium base, the total number of carbon atoms of the three alkyl groups of the quaternary ammonium base is 4 or more, preferably 5 or more, and more preferably an alkyl group having 3 to 10 carbon atoms. Is included. The coating containing these compounds is cured by radiation, preferably ultraviolet, to form the surface layer to be recorded.

The use of the compound having a quaternary ammonium base as described above improves water resistance and facilitates preparation of a coating solution. In addition, by using a compound having a carboxylic acid group, excellent drying properties can be obtained. Therefore, a recording substrate using these compounds is quick-drying. In addition, it is excellent in water resistance, for example, there is no bleeding of a print even when exposed to running water, and no film peeling occurs even when wiped after being exposed to running water. Further, the printing stability is good, and the surface hardness is high and the durability is excellent as compared with the related art. In addition, the resolution is high without dot bleeding, and the color printability is excellent. In addition, even when a recording surface layer is formed on a hydrophobic surface such as a protective film surface of an optical recording medium, adhesion is sufficient.

On the other hand, such an effect cannot be obtained with only one of the compounds, and the compound having a quaternary ammonium group alone has insufficient drying properties, and the compound having a carboxylic acid group alone has insufficient water resistance. Performance becomes insufficient. Further, when the total number of carbon atoms of the three alkyl groups of the quaternary ammonium base is 3 or less, mixing at the time of preparing the coating solution cannot be performed sufficiently, and white turbidity occurs.

Japanese Patent Application Laid-Open No. 1-18887 discloses an ink receiving layer containing a copolymer unit containing at least 1% by weight of a monomer unit having a quaternary ammonium salt and being substantially insoluble in water. Synonymous with surface layer)
It has been proposed to use it. However, unlike the present invention, the total number of carbon atoms of the three alkyl groups of the quaternary ammonium base is 3. Further, neither the use of a compound having a carboxylic acid group nor the radiation curing after forming a coating film has been performed. Furthermore, no compound containing a compound having a quaternary ammonium salt group as a monomer has been used.

[0014]

[Specific Configuration] Hereinafter, a specific configuration of the present invention will be described in detail.

The recording substrate of the present invention has a recording surface layer which can be written with an ink containing a water-soluble dye on a substrate, and the coating film for forming the recording surface layer has three alkyl groups. And a compound having a carboxylic acid group.

The compound having a quaternary ammonium base used in the present invention is one in which the total number of carbon atoms of the three alkyl groups of the quaternary ammonium base is 4 or more, preferably 5 or more. Furthermore, it has one alkyl group having 3 to 10 carbon atoms. In this case, the upper limit of the total number of carbon atoms of the three alkyl groups is usually about 20, preferably about 15.

The compound having such a quaternary ammonium base is a compound represented by Chemical Formula 3 or Chemical Formula 4. The chemical formulas 3 and 4 will be described.
⁰ represents a hydrogen atom or a methyl group. R ¹ , R ² and R ³ each represent an alkyl group, and the total number of carbon atoms of these three alkyl groups is 4 or more. Further, R ^1-
The total number of carbon atoms of the alkyl group for R ³ is preferably 5 or more, more preferably 5 to 15, and particularly preferably 5 to 15.
~ 12. One of R ^{1 to} R ³ is an alkyl group having 3 to 10 carbon atoms.

The alkyl groups represented by R ^{1 to} R ³ may be linear or branched, and preferably have about 1 to 10 carbon atoms. Specifically, methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso
-Butyl group, s-butyl group, t-butyl group, n-pentyl group, iso-pentyl group, neo-pentyl group, t-
Pentyl group, n-hexyl group, neo-hexyl group, i
so-hexyl group, n-heptyl group, n-octyl group,
Examples thereof include an n-nonyl group and an n-decyl group. Among them, R ¹ to
R ³ may be selected, but one of R ^{1 to} R ³ is an alkyl group having 3 to 10 carbon atoms, and R ^{1 to} R 3
It is preferable two among ³ is an alkyl group of 1 to 5 carbon atoms. In particular, ^one of R ^{1 to} R ³ is an alkyl group having 3 to 10 carbon atoms, and R ^{1 to} R 3
It is preferable two among the ^three is a methyl group.

These alkyl groups are preferably unsubstituted, but may have a substituent. Examples of such a substituent include a hydroxy group, an ether group and an ester group. Of these, those in which the terminal of the alkyl group is substituted with a hydroxyl group are preferable, and those in which the terminal of the alkyl group having 3 to 10 carbon atoms is substituted with a hydroxyl group are particularly preferable.

In the chemical formulas (3) and (4), L ¹ represents 1 to ¹ carbon atoms.
And 8 represents an alkylene group. Further, the number of carbon atoms is preferably 2 to 5, and the alkylene group may be linear or branched, but is preferably linear. Further, it may have a substituent such as an ether group or an ester group, but is preferably an unsubstituted one. These alkylene groups are at least one of an oxy group (-O-) and a carbonyl group (-CO-), for example, an oxy group (-
O-) and a carbonyloxy group (-COO-) may be present.

Specifically,-(CH ₂ ) _p- (p = 1 to
_{8), - C (CH 3} ) H-CH 2 -, - [(CH _{2) 2}
-O] _q- (CH ₂ )-(q = 1 to 2),-[(CH
₂ ) ₂ -COO] _r- (CH ₂ )-(r = 1 to 2), among which-(CH ₂ ) _2- and-(CH ₂ ) _{3
-, - (CH 2) 4} -, - (CH 2) 5 - , and the like are preferable.

[0022] X ^- represents a halide ion, Br
^-, Cl ^-, I ^-, and the like.

Specific examples of the compound having a quaternary ammonium base are shown below, but the present invention is not limited thereto.

[0024]

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The compound having such a quaternary ammonium base is prepared by reacting a (meth) acrylate compound having an alkylamino group with an alkyl halide in an organic solvent such as toluene in the presence of a polymerization inhibitor (such as m-dinitrobenzene). It is obtained by reacting below. The reaction may be performed by stirring at a temperature of about room temperature (15 ° C. to 30 ° C.) to about 150 ° C. for about 5 to 50 hours.

The following is a synthesis example.

Synthesis Example 1 Synthesis of Exemplified Compound a-1 18 g of dimethylaminopropyl methacrylate and 15 g of n-pentyl bromide were placed in toluene, and m-dinitrobenzene was further added to a concentration of 4 wt%. The solution was stirred at room temperature for 30 hours to give a white precipitate. This was filtered, further washed with toluene, and purified to obtain the desired product.

Synthesis Example 2 Synthesis of Exemplified Compound a-2 18 g of dimethylaminopropyl methacrylate and 9.5 g of n-propyl chloride were placed in toluene, and m-
Dinitrobenzene was added to 4 wt%. This solution was stirred at 100 ° C. for 30 hours to obtain a white precipitate.
This was filtered, further washed with toluene, and purified to obtain the desired product.

Other compounds were synthesized in the same manner as described above.

Such a compound can be identified by elemental analysis, ¹ H nuclear magnetic resonance spectrum ( ¹ H NMR), infrared absorption spectrum (IR) and the like.

The compound having a quaternary ammonium base is 1
Only one kind may be used, or two or more kinds may be used in combination. The content of these compounds in the surface layer to be recorded is preferably 1 to 50% by weight, more preferably 3 to 30% by weight in the coating film. With such a content, the water resistance is sufficiently improved. On the other hand, if the content is too small, the effect of the present invention cannot be obtained. If the content is too large, the compatibility with other coating liquid components becomes poor and crystallization occurs. Further, even after radiation curing, sufficient water resistance cannot be obtained, and the strength of the coating film is reduced.

The presence of a quaternary ammonium base is advantageous in terms of printing stability when using an ink containing a water-soluble dye having an anion such as a sulfonic acid anion.

The compound having a carboxylic acid group used in the present invention is not particularly limited as long as it is a compound having at least one carboxylic acid group, and is at least one of (meth) acrylic acid and derivatives thereof. Is preferred. Among them, the compound represented by Chemical formula 6 is preferable.

[0034]

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In formula 6, R ⁰ represents a hydrogen atom or a methyl group. L ² represents an alkylene group. The alkylene group may be linear or may have a branch,
The number of carbon atoms is preferably 1 to 8. _{Specifically, - (CH 2) s -} (s = 1~8), - C (CH 3)
H-CH _2- and the like, among which-(CH ₂ ) ₂
—, — (CH ₂ ) ₅ — and the like are preferred. It is preferably unsubstituted, but may have a substituent. In this case, examples of the substituent include a carboxylic acid group and a hydroxy group.

T is 0 or 1 to 5, and more preferably 0 or 1 to 3. The following can be illustrated as specific examples of the compound of Chemical formula 6.

[0037]

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In the above exemplified compounds, b-7 is commercially available as Aronix M-5600 (manufactured by Toa Gosei Chemical), and b-8 is commercially available as Aronix M-5300 (manufactured by Toa Gosei Chemical).

The following are other derivatives of (meth) acrylic acid.

[0040]

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[0041]

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In Chemical Formulas 8 and 9, R ⁰ represents a hydrogen atom or a methyl group. L ³ is an alkylene group having 2 to 6 carbon atoms which may be substituted by a carboxylic acid group or the like; L ⁴ is 2 carbon atoms which may be substituted by a carboxylic acid group or the like;
And 6 represents an alkylene group, an arylene group such as a phenylene group, or a heterocyclic group. u is 1 to 5, especially 1 or 2.

Specific examples of the compound of formula 8 include those of formula 10.

[0044]

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In the formula 8, R ⁰ is H, and u
= 1, a compound in which L ³ and L ⁴ are ethylene groups is Aronix M-5800 (manufactured by Toagosei Chemical Co., Ltd.), and R ⁰ is H, u = 1, L ³ is an ethylene group, and L ⁴ is o. The compound represented by Chemical formula 10, which is a phenylene group, is commercially available as ARONIX M-5400 (manufactured by Toa Gosei Chemical Co., Ltd.).

Further, the compounds of the formulas 11 and 12 can also be used.

[0047]

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[0048]

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Other compounds having a carboxylic acid group include allylacetic acid, allyloxypropionic acid, itaconic acid, maleic acid, allylmalonic acid and derivatives thereof (for example, itaconic acid monoethyl ester, itaconic acid monomethyl ester, maleic acid monoamide) , Maleic acid monomethyl ester and maleic acid monoethyl ester).

The compounds having a carboxylic acid group are preferably used as monomers.
It may be used as an oligomer.

The compounds having a carboxylic acid group may be used alone or in combination of two or more. The content of these compounds in the surface layer to be recorded is preferably 5 to 70% by weight, more preferably 15 to 60% by weight in the coating film before curing. With such a content, the drying property is sufficiently improved. On the other hand, if the content is too small, the effect of the present invention cannot be obtained, and if the content is too large, print quality such as ink repellency and dot bleeding is deteriorated.

The ratio of the compound having a quaternary ammonium salt group to the compound having a carboxylic acid group in the coating film is 3/1 by weight ratio of the compound having a quaternary ammonium salt group / the compound having a carboxylic acid group. １ ／ 1/20, preferably 2/1 １ ／ 1/10. With such a ratio, the effect of the present invention is improved.

In the present invention, at least one of the compound having a quaternary ammonium base and the compound having a carboxylic acid group may be a monomer having an ethylenically unsaturated reactive group at the terminal, and more preferably a monomer having an ethylenically unsaturated reactive group. Preferably, at least one of the compound having a quaternary ammonium base and the compound having a carboxylic acid group is a monomer having an ethylenically unsaturated reactive group at a terminal. When two or more compounds are used, all of the compounds are preferably monomers having an ethylenically unsaturated reactive group at the terminal.

By using such a compound, radiation curing can be performed, and the water resistance after curing can be improved. In addition, the bleeding of the printing dots is eliminated, and the printing quality is improved.

In the present invention, it is preferable that the coating film of the surface layer to be recorded further contains a compound having a hydroxyl group.
As a result, an effect of improving the film quality is obtained, and tack and the like are less likely to occur.

As such a compound having a hydroxyl group, a (meth) acrylate compound is preferable, and specifically, polyethylene glycol mono (meth) acrylate [CH ₂ ＣＨCH—C (O) —O— (CH ₂ CH ₂ O)
_{n -H, CH 2 = C (} CH 3) -C (O) -O- (CH
₂ CH ₂ O) _n -H: n = 1 to 4], pentaerythritol bis (meth) acrylate, pentaerythritol tri (meth) acrylate and the like.

When such a compound is contained, the content in the coating film is preferably 30% by weight or less, more preferably 1 to 25% by weight. With such a content, the above effect is further improved. On the other hand, if the amount is small, the effect is ineffective, and if the amount is too large, the water resistance is lowered and the curing is poor.

In the present invention, a compound having a morpholino group may be used together with or instead of the compound having a hydroxyl group in the coating film of the recording surface layer. By using such a compound, the effect of improving the film quality can be obtained as in the case of the compound having a hydroxyl group.

As such a compound having a morpholino group, a (meth) acrylate compound is preferable, and specific examples thereof include acryloylmorpholine and methacryloylmorpholine.

When such a compound is contained, the content in the coating film is preferably 40 wt% or less, more preferably 5 to 35 wt%. With such a content, the above effect is improved. On the other hand, if the amount is small, the effect is ineffective, and if the amount is too large, poor curing and poor print quality occur.

The recording surface layer is formed by curing the coating film by radiation, and the radiation used for curing is electron beam,
Ultraviolet rays and the like are mentioned, and ultraviolet rays are particularly preferable. Therefore,
The coating film preferably contains a polymerization initiator, particularly a photopolymerization initiator.

The photopolymerization initiator is not particularly limited.
Benzoic acid esters, benzophenone derivatives, benzoin derivatives, thioxanthone derivatives, acetophenone derivatives, propiophenone derivatives, benzyl and the like can be used.

Specifically, methyl-orthobenzoylbenzoate, benzophenone, 4,4-bisdiethylaminobenzophenone, dibenzosuberone, benzoylalkyl ether (having an alkyl group having 1 to 8 carbon atoms and optionally containing a branch), 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) oxime, 1-phenyl-1,2-propanedione-2- (o
-Benzoyl) oxime, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, chlorinated acetophenone derivatives, 4-isopropyl-2-hydroxy-2-methyl-propiophenone,
-Hydroxy-2-methylpropiophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one and benzyl. Of these, particularly preferred polymerization initiators include 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2,2-dimethoxy-2-phenylacetophenone, methyl-orthobenzoylbenzoate and the like. Among these particularly preferred polymerization initiators, 2-hydroxy-2-methyl-1-phenylpropan-1-one is Darocur 11
73 (Merck) and 2,2-dimethoxy-2-phenylacetophenone are commercially available as Irgacure 651 (Nippon Ciba Geigy).

The content of the polymerization initiator in the coating film of the recording surface layer is preferably 10% by weight or less, more preferably 0.1% by weight or less.
10 to 10% by weight, particularly preferably 0.3 to 10% by weight.
If the content is too small, sufficient action as a polymerization initiator cannot be obtained, and if it is too large, coloring, weather yellowing, corrosion, etc. occur.

Further, in addition to the above-mentioned compound having a quaternary ammonium salt group and the compound having a carboxylic acid group, the coating film of the recording surface layer of the present invention may further comprise, if necessary, an ethylenically unsaturated reactive compound. A monomer or oligomer having a group, or both, can be contained.

There is no particular limitation on such a compound, and for example, any of acrylate, acrylamide and vinyl compounds can be used.

More specifically, acrylamide-based N, N
-Methylenebisacrylamide, acrylate-based ethylene glycol bis (meth) acrylate, diethylene glycol bis (meth) acrylate, triethylene glycol bis (meth) acrylate, hexaethylene glycol bis (meth) acrylate, propylene glycol bis (meth) acrylate, 1 , 4-butanediol bisacrylate, 1,6-hexanediol bisacrylate, trimethylolpropane triacrylate, vinyl 3,9-divinylspirobi (m-dioxane), divinyl adipate and the like. Preferred examples include N, N-methylenebisacrylamide, triethylene glycol bismethacrylate, hexaethylene glycol bis (meth) acrylate, and the like. .

The amount of these compounds to be added is determined depending on the number of ethylenically unsaturated reactive groups present at the terminals of the molecule and other components. Preferably 50% by weight or less of the coating film, more preferably 4% by weight.
0 wt% or less, particularly preferably 25 wt% or less. By containing in this range, of the recording surface layer, for example,
The water resistance such that the film properties do not change even when exposed to running water is further improved, and the water resistance of printing is further improved. Further, since the hardness of the film can be improved while maintaining the ink adsorbing property, an appropriate hardness can be obtained. On the other hand, if the addition amount is too large, the recording surface layer is hard, easily fragile,
The ink absorption speed decreases, the ink dries slowly, and ink swells and ink cracks occur.

The recording surface layer of the present invention may further contain a resin. As such a resin,
Although it depends on other components, any component having good compatibility with other components may be used. For example, acrylic resin, methacrylic resin, polyamide such as nylon, melamine resin, cellulosic resin, polyvinyl alcohol, polyester and the like may be used. Such a resin may be a resin obtained by including a radiation-curable monomer or oligomer in a coating film and curing the coating film.

The amount of the resin added is preferably not more than 50% by weight, more preferably not more than 30% by weight of the coating on the surface layer to be recorded. With such an addition amount, the strength of the coating film is improved and the water resistance is also improved. In addition, the warpage of the base is reduced. On the other hand, if the addition amount is too large, the ink tends to be repelled, and the quick-drying property of the ink tends to deteriorate.

In the recording surface layer of the present invention, only a solvent is promptly permeated into a wide area without diffusing a dye, so that the function as an ink receiving layer is improved and drying is promoted. It is preferable to include particles. As such porous particles, generally used porous particles can be used for such a purpose. Such porous particles include silica, clay, talc, diatomaceous earth, calcium carbonate, calcium sulfate, barium sulfate,
Examples include inorganic pigments such as aluminum silicate, synthetic zeolite, alumina, zinc oxide, titanium oxide, lithobon, and titanium white.

The average particle diameter of these porous particles is preferably 0.001 to 50 μm, more preferably 0.001 to 50 μm.
３０30 μm. If the average particle size is too large, the film tends to be brittle or the surface tends to be rough. If it is too small, the penetration of the solvent tends to be slow.

Among these, the porous particles preferably used in the present invention include silica, alumina, titanium oxide and the like. As the silica, ultrafine anhydrous silica is preferable, and the average particle size of the primary particles is preferably 0.001 to 30 μm. These include Aerosil TT600, OX50,
380, 200, 130, 300, MOX80, MOX
170, COK84 (available from Aerosil, SiLCRON)
G-100, G-100T, G-600, G-601,
G-602 and G-603 (manufactured by SCM Chemicals) are commercially available. Examples of alumina include those commercially available under the trade names such as Aluminum Oxide C (manufactured by Aerosil) and titanium oxides such as Titanium Oxide P25 (manufactured by Aerosil).

The addition amount of these porous particles may be determined according to the use and purpose. However, when the content is too large, the effect of diffusing the ink is enhanced, but the recording surface layer is brittle, and the durability tends to be insufficient. Therefore, the content is preferably 70% by weight or less, more preferably 50% by weight or less. When two or more kinds of such porous particles are used as a mixture, the total amount of the porous particles is preferably 70% by weight or less. The lower limit of the amount is not particularly limited, but is usually about 10% by weight.

Also, smectite can be used as such porous particles.

The recording surface layer of the present invention may contain a photopolymerization accelerator such as triethanolamine and 2- (dimethylamino) ethylbenzoate, a chain transfer agent, a radical polymerization inhibitor such as phenothiazine, N-nitroso A stabilizer such as a chelating agent such as phenylhydroxylamine aluminum salt may be added.

In the present invention, in order to form a recording surface layer on a substrate, first, components contained in a coating film of the recording surface layer such as a compound having a quaternary ammonium salt group and a compound having a carboxylic acid group are contained. A coating solution to be prepared is prepared, and this coating solution is applied on a substrate.

In preparing the coating solution, a solvent may be used. However, when a liquid component is contained in the components of the coating solution, the solvent is not necessarily used. Since the compound having a quaternary ammonium base or the compound having a carboxylic acid group used in the present invention is a liquid when it is a monomer having an ethylenically unsaturated reactive group, it is not usually necessary to use a solvent.

When a solvent is used, methanol, ethanol, butyl carbitol, ethyl cellosolve and the like are preferable. These solvents may be used as a mixture of two or more kinds. In this case, there is no particular limitation on the type and content of the solvent used in the coating liquid, the mixing ratio of the plurality of solvents, and the like.

As a coating method, any of commonly used methods such as spin coating, spray coating, dipping, gravure roll, knife coater, reverse roll, screen printing, and bar coater can be used. it can. When a coating solution containing lipophilic smectite and having an appropriately adjusted viscosity is used, it can be coated well using a screen printing method, a gravure roll method, a bar coater method, or the like.

In the present invention, the coating film thus obtained is irradiated with radiation and cured. In the case where a solvent is used for the coating liquid, it may be applied to the substrate by the above-described appropriate method, then dried to remove the solvent used to form a coating film, and then cured by irradiation with radiation. As the radiation used, ultraviolet rays are preferable as described above. In this case, the intensity of the ultraviolet light to be irradiated is about 50 mW / cm ² or more, and the irradiation amount is 200 to 2000 mJ.
/ cm ² may be used. Further, as the ultraviolet ray source, a usual one such as a mercury lamp may be used.

The thickness of the recording surface layer thus formed is 1 to 100 μm, more preferably 3 to 30 μm. If the thickness is too large, the recording substrate is likely to be warped or insufficiently cured. On the other hand, if it is too thin, the permeability of the solvent decreases, and the ink after printing becomes difficult to dry.

The contact angle of the recording surface layer with water at 25 ° C. is preferably 60 ° or less, more preferably 40 °.
It is as follows. By having such a contact angle, it is possible to obtain a recording surface layer having excellent adhesion to a hydrophobic substrate and writable with an ink containing a water-soluble dye. If the contact angle is too high, writing with an ink containing a water-soluble dye becomes difficult.

As the substrate having the surface layer to be recorded according to the present invention, any substrate usually used in an ink jet recording system, such as paper, slide film, OHP (overhead projector) film, CMF (color mosaic filter), etc. may be used. Can be. However, the substrate exhibiting more characteristics is preferably a substrate having a hydrophobic surface, and is preferably an optical recording medium having a radiation-curable protective film, particularly an optical recording medium such as a recordable compact disc having an ultraviolet-curable protective film. Medium. The recording surface layer of the present invention formed on the surface of the recordable compact disc having a hydrophobic surface on which a label is usually printed also has high adhesion to the hydrophobic surface of the substrate. Then, on this surface layer to be recorded, the user can record the contents of the optical recording by using an ink containing a water-soluble dye such as an inkjet ink.

As the ultraviolet curing protective film of the optical recording medium,
Usually, any material can be used as long as it is used as a protective film of such a recordable compact disc, and there is no particular limitation. For example, a UV curable compound such as a polyfunctional oligoester acrylate is contained,
Various materials such as those having a thickness of about 5 to 100 μm may be used. In addition, the present invention uses a hydrophobic substrate at 25 ° C.
Is effective for those having a contact angle with water of 40 ° or more, particularly 60 to 90 °.

FIG. 1 shows an example of an optical recording medium having a recording surface layer according to the present invention.

The optical recording medium 11 shown in FIG.
2 has a recording layer 13 containing a dye as a main component.
3, a reflective layer 14, a protective film 15, and a recording surface layer 17 on the protective film 15.

The substrate 12 has recording light and reproducing light (wavelength 6
A material formed of a resin or glass which is substantially transparent (preferably at a transmittance of 88% or more) to semiconductor laser light having a wavelength of about 00 to 900 nm, particularly about 770 to 900 nm, particularly 780 nm may be used. This enables recording and reproduction from the back side of the substrate.

As the material of the substrate, a resin is preferably used, and various thermoplastic resins such as a polycarbonate resin, an acrylic resin, an amorphous polyolefin, and TPX are suitable. The substrate 12 may be manufactured according to a known method such as injection molding. At this time, it is preferable to form a predetermined pattern such as the groove 21 on the substrate surface for tracking, addressing, and the like. After manufacturing the substrate 12, a resin layer having a predetermined pattern such as a groove may be formed by a 2P method or the like.

The recording layer 13 may contain only one type of dye, or may have a structure in which two or more types of dyes are compatible.

The light absorbing dye used for the recording layer 13 has an absorption maximum of 600 to 900 nm, preferably 600 to 900 nm.
800 nm, more preferably 650-750 nm,
There is no other particular limitation, for example, one or more of cyanine-based, phthalocyanine-based, naphthalocyanine-based, anthraquinone-based, azo-based, triphenylmethane-based, pyrylium or thiapyrylium salt-based, squalilium-based, croconium-based, metal complex dye-based and the like. Two or more types may be appropriately selected depending on the purpose.

A quencher may be mixed with the light absorbing dye. Further, an ion binder of a dye cation and a quencher anion may be used as the light absorbing dye.

The quencher is preferably a metal complex such as an acetylacetonate type, a bisdithiol type such as a bisdithio-α-diketone type or a bisphenyldithiol type, a thiocatechol type, a salicylaldehyde oxime type or a thiobisphenolate type. . Further, amine quencher such as amine compound having nitrogen radical cation or hindered amine is also suitable.

The dye constituting the conjugate is preferably a cyanine dye having an indolenine ring, and the quencher is preferably a metal complex dye such as a bisphenyldithiol metal complex.

The recording layer 13 is formed by a spin coating method in which a coating solution containing a dye and an organic solvent is used, and the coating solution is spread and applied on a rotating substrate.

The organic solvent used for the coating solution for forming a recording is selected from aliphatic hydrocarbons, alcohols, ketones, esters, ethers, aromatics, alkyl halides, etc., depending on the dye used. May be selected as appropriate. After spin coating, the coating film is dried if necessary.

The thickness of the recording layer 13 formed in this manner is appropriately set according to the target reflectance and the like, but is usually about 1000 to 3000 A.

The recording layer 13 is directly adhered to the reflective layer 1.
4 are provided. For the reflective layer 14, a high-reflectance material is used. Such materials include Au, Cu, Ag, Al
And alloys containing these are preferred.

In order to form the reflective layer 14, various vapor deposition methods such as sputtering and vapor deposition may be used.

The thickness of the reflection layer 14 is preferably 500 A or more. Although there is no particular upper limit for the thickness, it is preferably about 1700 A or less in consideration of cost, production work time, and the like.

On the reflective layer 14, a protective film 15 is provided. As described above, the protective film 15 is preferably made of various resin materials such as an ultraviolet curable resin, for example, and is preferably 0.5
About 100 μm, more preferably about 1 to 50 μm, especially about 3 to
The layer may be formed to a thickness of 30 μm. The protective film 15 may be in the form of a layer or a sheet. The protective film 15 may be formed by an ordinary method such as spin coating, gravure coating, spray coating, dipping, or the like. If the protective film is too thin, the effect as the protective film cannot be sufficiently obtained,
A recording signal error is likely to occur. On the other hand, if the thickness is too large, warping of the recording medium and cracks in the protective film are likely to occur due to the shrinkage of the resin film during curing.
Although the protective film in the illustrated example has only one layer, the protective film may have a multilayer structure of two or more layers. When two or more layers are used, the total film thickness may be in the above range.

In the present invention, at least one of the protective film 15 and the recording surface layer 17 provided on the reflective layer 14 is used.
Preferably, the layer contains a white pigment. When the protective film has a multilayer structure, any protective film may be used, or two or more protective films may be contained.

As the white pigment, calcium sulfate, barium sulfate, zinc oxide, titanium oxide, lithobon, titanium white and the like can be used. By using these white pigments, the color developability in color printing is improved. The average particle size of the white pigment to be used is not particularly limited.
0 μm or less, preferably about 0.001 to 20 μm. This is because if the average particle size is too large, the film tends to be brittle. Further, the content is 0.1 to 2 of the entire layer.
It is preferred to be about 0% by weight. This is because if the content is too small, the addition is ineffective, and if the content is too large, the film becomes brittle. In particular, in the present invention, the protective film is 2
It is preferable that at least one layer is provided and one layer contains a white pigment.

When writing on an optical recording medium having such a recording surface layer, writing may be performed with an ordinary pen or the like using an ink containing a water-soluble dye. It is preferable to use a writing device of an ink jet recording system.

The ink to be used is not particularly limited as long as it contains a water-soluble dye, and any ink can be used as long as it is an ink used in a writing apparatus of an ink jet recording system.

Examples of the water-soluble dye include C.I. I. Direct black 17, 19, 32, 51, 71, 10
8, 146, C.I. I. Direct Blue 6, 22, 2
5, 71, 86, 90, 106, 199, C.I. I. Direct Red 1, 4, 17, 28, 83, C.I. I. Direct Yellow 12, 24, 26, 86, 98, 14
2, C.I. I. Direct orange 34, 39, 44, 4
6, 60, C.I. I. Direct violet 47, 4
8, C.I. I. Direct Brown 109, C.I. I. Direct dyes such as Direct Green 59; I. Acid Black 2, 7, 24, 26, 31, 52, 63, 11
2,118, C.I. I. Acid Blue 9, 22, 40,
59, 93, 102, 104, 113, 117, 12
0, 167, 229, 234, C.I. I. Acid Red 1, 6, 32, 37, 51, 52, 80, 85, 87,
92, 94, 115, 180, 256, 317, 31
5, C.I. I. Acid Yellow 11, 17, 23, 2
5, 29, 42, 61, 71, C.I. I. Acid orange 7, 19, C.I. I. Acid dyes such as Acid Violet 49 are preferred. I. Basic Black 2, C.I. I. Basic Blue 1, 3, 5, 7, 9,
24, 25, 26, 28, 29, C.I. I. Basic Red 1, 2, 9, 12, 13, 14, 37, C.I. I. Basic Violet 7, 14, 27, C.I. I. Food Black 1, 2, Water Black 187L and the like. Some of these dyes also apply,
Those having an anionic group such as a sulfonic acid group or a salt thereof, or a phenolic hydroxyl group or a carboxylic acid group in the molecule are also preferable.

[0107]

The present invention will be specifically described below with reference to examples.

Example 1 A solution having the following composition was placed in a mixer and stirred for 1 hour to obtain a coating solution.
No. 1 was prepared. Compound a-1 10 parts by weight Compound b-7 (Aronix M-5600: manufactured by Toa Gosei Chemical Co., Ltd.) 40 parts by weight Ethylene glycol monomethacrylate 20 parts by weight Polymerization initiator [2-hydroxy-2-methyl-1-phenylpropane] -1-one (Darocure 1173: manufactured by Merck)] 5 parts by weight Crosslinking agent (Blemmer GMR: manufactured by NOF Corporation) 5 parts by weight 20 parts by weight

Using this coating solution No. 1, a coating film was formed on a protective film by screen printing using a write-once compact disc (CD-R) as a substrate, dried, and then dried at 800 mJ.
UV curing at an irradiation dose of / cm ^{2 and} the recording surface layer (8
μm thick) (see FIG. 1).

The CD-R protective film was obtained by curing a coating film having the following composition with ultraviolet rays, and had a thickness of 6 μm. The material of the reflection layer is gold.

Composition of protective film 97 parts by weight of polyfunctional oligoester acrylate (Aronix M-8100: manufactured by Toa Gosei Chemical Co., Ltd.) 3 parts by weight of 2-hydroxy-2-methyl-1-phenylpropan-1-one (Darocur 1173: Merck Company)

The optical recording medium thus obtained is designated as Sample No. 1.

In sample No. 1, a recording surface layer was formed by using coating liquid No. 2 in which compound a-1 of coating liquid No. 1 for forming a recording surface layer was changed to compound a-2. This is designated as Sample No. 2.

In the coating solution No. 1, the compound a-
A compound a-3 was used in place of 1, and this was changed to 20 parts by weight, a compound b-7 was changed to 35 parts by weight, and 20 parts by weight of ethylene glycol monomethacrylate was changed to 15 parts by weight of ethylene glycol monoacrylate in the same manner. Preparation of coating liquid No. 3 was prepared. Sample No. 3 was obtained by using the coating liquid No. 3 to form a recording surface layer.

Further, in coating solution No. 1, compound a
Coating solution No. 4 was prepared in the same manner except that compound a-4 was used in place of -1 and 15 parts by weight thereof, compound b-3 was 35 parts by weight, and acryloylmorpholine was used in place of ethylene glycol monomethacrylate. Was prepared.
Sample No. 4 was prepared by using this coating liquid No. 4 to form a recording surface layer.

In the coating solution No. 1, a comparative compound represented by the following formula 13 was used in place of the compound a-1.
When the preparation of o.5 was attempted, mixing did not proceed well and cloudiness occurred. Sample No. 5 was obtained by forming a recording surface layer using this coating liquid No. 5.

[0117]

Embedded image

Coating solution No. 6 was prepared in the same manner as in coating solution No. 1, except that compound a-1 was not added, compound b-7 was changed to 50 parts by weight, and ethylene glycol monomethacrylate was changed to 20 parts by weight. . Sample No. 6 was prepared by using this coating liquid No. 6 to form a recording surface layer.

Further, in coating solution No. 1, compound b
Coating Liquid No. 7 was prepared in the same manner except that Compound a-1 was 20 parts by weight and ethylene glycol monomethacrylate was 50 parts by weight without adding -7. This coating liquid No. 7
Sample No. 7 in which a recording surface layer was formed using
And

Sample Nos. 1 to 7 were recorded by an ink jet recording system using inks having the following compositions.

Ink composition Yellow ink C.I. I. Direct Yellow 86 2 parts by weight Diethylene glycol 20 parts by weight Polyethylene glycol 10 parts by weight Water 70 parts by weight Red ink I. Acid Red 35 2 parts by weight Diethylene glycol 20 parts by weight Polyethylene glycol 10 parts by weight Water 70 parts by weight Blue ink C.I. I. Direct Blue 86 2 parts by weight Diethylene glycol 20 parts by weight Polyethylene glycol 10 parts by weight Water 70 parts by weight Black ink C.I. I. Food Black 2 2 parts by weight Diethylene glycol 20 parts by weight Polyethylene glycol 10 parts by weight Water 70 parts by weight

The following evaluation was performed on the recordings thus obtained. Table 1 shows the results.

(1) Drying time of printing (quick drying) After printing, and after printing, the time until the ink does not adhere to the finger when touching the printing surface is defined as the drying time. displayed. ◎ when the drying time is 30 seconds or less, 、 when the drying time exceeds 30 seconds and 1 minute or less,
The case where the drying time exceeded 1 minute was rated as Δ, and the case where the drying was not performed for 24 hours or more was rated as x.

(2) Water resistance After printing, and after drying of the print, the surface layer to be recorded was placed in running water for 1 hour.
Exposure for a minute, and the following were examined.

(2-1) Ink Adsorbing Property The characters before and after the printing surface was exposed to running water for 1 minute were visually observed to examine the density of the characters. O indicates that the character density hardly changes before and after exposure to running water, O indicates that the character is slightly readable, but X indicates that the character disappears and becomes unreadable.

(2-2) Membrane: The case where the layer surface hardly changes even after being exposed to running water for 1 minute is indicated by “○”, the case where the layer is slightly softened is indicated by “△”, and the case where the layer flows or peels off with running water is indicated by “×”. To be displayed.

(2-3) Wipeability When the layer surface after being exposed to running water for 1 minute is wiped off with a cloth (towel, etc.) or paper (paper towel, tissue paper, etc.), there is no change in the layer surface. 、, the case where the layer is partially peeled off when strongly rubbed is indicated by Δ, and the case where the entire layer is easily peeled is indicated as × in the table.

(3) Resolution The printed dots were observed with a stereoscopic microscope to check whether or not bleeding had occurred. In the table, ○ indicates no bleeding, △ indicates slight bleeding, and × indicates severe bleeding.

[0129]

[Table 1]

Table 1 clearly shows the effect of the present invention.
Samples Nos. 1 to 4 of the present invention also showed good adhesion between the protective film and the recording surface layer. Adhesion is made using 3M Scotch Clear Tape 600.
After attaching an adhesive surface of 1.2 cm × 1.0 cm to the surface layer to be recorded, it was peeled off and examined for peeling of the surface layer to be recorded. None of the samples of the present invention peeled off.

Example 2 In the coating liquid No. 1 of the sample No. 1 of Example 1, except that the compound a-2 and the compound a-4 were used in 5 parts by weight and 5 parts by weight instead of the compound a-1. A coating solution was prepared in the same manner, and a sample was similarly obtained.

When this sample was evaluated in the same manner as in Example 1, it was found that good results equivalent to those of Sample No. 1 were obtained.

Example 3 In each of the coating solutions of Sample Nos. 1 to 4 of Example 1, compounds b-1 to b-6 were used instead of compound b-7.
A coating solution was prepared using each of b-8, and samples were prepared using these coating solutions, and the characteristics were evaluated in the same manner as in Example 1. As a result, the same goodness as in Sample Nos. Results were obtained. Compounds b-3 and b-4 are combined with 2
Similar good results were obtained using the coating solution prepared using 0 parts by weight. Some of the results are also shown in Table 1.

Example 4 The same procedure as in Example 1 was repeated except that the coating liquid No. 3 of the sample No. 3 was replaced by 10 parts by weight of acryloylmorpholine and 5 parts by weight of ethylene glycol monoacrylate instead of 15 parts by weight of ethylene glycol monoacrylate. A sample was prepared in the same manner as above, a sample was prepared in the same manner, and the characteristics were evaluated in the same manner.

Example 5 In the sample No. 1 of Example 1, instead of Aerosil TT-600 as the porous material, SiLCRONG was used.
-100, G-100T, G-600, G-601, G
-602 and G-603 (manufactured by SCM Chemicals) were similarly used to prepare samples and evaluated in the same manner. As a result, the same good results as those of Sample No. 1 were obtained.

Example 6 In each of the samples No. 1 to No. 4 of the present invention of Example 1 and the samples of Examples 2 to 5, except that the protective film of the CD-R substrate had a two-layer structure, A sample was obtained. When each of these samples was evaluated in the same manner as in Example 1, the same good results as those of the corresponding samples were obtained. Further, in these samples, since the second protective film contained a white pigment, the coloring property was good and easy to see.

The compositions and thicknesses of the first and second protective films are as follows, and were prepared in the same manner as the CD-R protective film of Example 1.

First protective film (reflective layer side: 6 μm thick) 97 parts by weight of polyfunctional oligoester acrylate (Aronix M-8100: manufactured by Toa Gosei Chemical Co., Ltd.) 2-hydroxy-2-methyl-1-phenylpropane-1 -On 3 parts by weight (Darocur 1173: manufactured by Merck) Second protective film (surface coating layer side: 10 μm thick) 92 parts by weight of polyfunctional oligoester acrylate (Aronix M-8100: manufactured by Toa Gosei Chemical) 2-hydroxy 3 parts by weight of 2-methyl-1-phenylpropan-1-one (Darocure 1173: manufactured by Merck) 5 parts by weight of titanium white (average particle size 0.03 μm)

[0139]

According to the present invention, a recording substrate having a recording surface layer excellent in water resistance such as no printing or peeling of the entire layer can be obtained even when wiped after being exposed to running water. Further, the adhesiveness to the substrate is good and the surface hardness is sufficient, and coating can be performed in a single coating step. Another important effect is that the printing stability is good, the drying time after writing with ink is shorter, the surface hardness is high, the durability is excellent, and the dot is not blurred and the resolution is high compared to the conventional one. And especially excellent color printability. Furthermore, since the monomer serves as a solvent, there is an advantage that a solvent is not required.

[Brief description of the drawings]

FIG. 1 is a partial sectional view showing an example of an optical recording medium of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Optical recording medium 12 Substrate 13 Recording layer 14 Reflection layer 15 Protective film 17 Recording surface layer 21 Groove

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-242578 (JP, A) JP-A-6-340164 (JP, A) JP-A-4-69277 (JP, A) JP-A-2- 164586 (JP, A) JP-A-2-215588 (JP, A) JP-A-4-59286 (JP, A) JP-A-5-278324 (JP, A) (58) Fields investigated (Int. ⁷ , DB name) B41M 5/00

Claims (10)

(57) [Claims] 1. A compound having a recording surface layer writable with an ink containing a water-soluble dye on a substrate, wherein the recording surface layer comprises a compound having a quaternary ammonium base having three alkyl groups. A recording substrate, which is obtained by radiation-curing a coating film containing a compound having a carboxylic acid group, and wherein the compound having a quaternary ammonium base is a monomer represented by the following chemical formula (1) or (2). Embedded image Embedded image [In each of Chemical formulas 1 and 2, R ⁰ represents a hydrogen atom or a methyl group. R ¹ , R ² and R ³ each represent an alkyl group, and the total number of carbon atoms of these three alkyl groups is 4 or more. L ¹ represents an alkylene group having 1 to 8 carbon atoms in which one or more of an oxy group (—O—) and a carbonyl group (—CO—) may intervene;
One of R ¹ , R ² and R ³ has 3 carbon atoms.
10 to 10 alkyl groups. X ^- represents a halide ion. ] 2. The method according to claim 1, wherein the compound having a carboxylic acid group is at least one of (meth) acrylic acid and a derivative thereof.
The recording substrate according to claim 1, which is a seed. 3. The recording substrate according to claim 1, wherein the curing is ultraviolet curing. 4. The recording substrate according to claim 1, wherein the coating further contains a compound having a hydroxyl group. 5. The recording substrate according to claim 1, wherein said coating film further contains a compound having a morpholino group. 6. The recording substrate according to claim 1, wherein the recording surface layer further contains porous particles. 7. The recording substrate according to claim 1, wherein the writing is performed by an ink jet recording method. 8. The recording substrate according to claim 1, wherein said substrate is an optical recording medium having a radiation-curable protective film. 9. The recording substrate according to claim 1, wherein said substrate is an optical recording medium having an ultraviolet curing protective film. 10. The optical recording medium has a reflective layer in close contact with a recording layer, has at least one protective film including the protective film on the reflective layer, and has the recording surface layer and the protective layer. 10. The recording substrate according to claim 8, wherein at least one layer of the film contains a white pigment.