JP2001256685A - Magneto-optical recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magneto-optical recording medium having satisfactory lubricity and which will not cause head crash. SOLUTION: In the magneto-optical recording medium 1 comprising an inorganic enhance layer 3, a magneto-optical recording layer 4, an inorganic protective layer 5 and an organic protective layer 6 formed successively on a transparent substrate 2, the organic protective layer 6 is formed by curing a UV-curing resin comprising a mixture of epoxy novolak acrylate, ethoxylated trimethylolpropane triacrylate and dipropylene glycol diacrylate, and further comprising 1α-hydroxyketone, α-amine ketone and a polyether modified silicone polymer, each of which is mixed in a prescribed proportion to the amount of the mixture.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magneto-optical recording medium, and more particularly to lubricity with a head for recording and reproducing data on and from the magneto-optical recording medium.

[0002]

2. Description of the Related Art Generally, a recordable optical disk is made of an organic dye or a metal alloy thin film on a metal master (stamper) having grooves and pits formed thereon and a transparent substrate on which the grooves and pits are transferred by injection molding or the like. Forming a recording layer, further comprising a metallic reflective film, a protective layer of a polymer resin, for example,
Some are disclosed in JP-A-6-259826 and JP-A-7-6418.

JP-A-6-259826 discloses a magneto-optical recording layer formed sequentially on a substrate and a scratch-resistant protective layer, wherein the scratch-resistant protective layer is formed of pentaerythritol triacrylate and tetraacrylate. When a curable resin containing 10 to 90% by weight of the mixture of (1) to (3) is used, it is possible to obtain a magneto-optical recording medium which has excellent scratch resistance and weather resistance, suppresses the occurrence of scratches due to the flying head, and prevents head crash and dust generation. It is disclosed that it is possible. Japanese Patent Application Laid-Open No. 7-6418 discloses a multi-layered magneto-optical recording layer sequentially formed on a disk-shaped substrate and a protective layer, and the protective layer has a coupling of 0.1 to 5 wt%. It is disclosed that when an agent is included, a magneto-optical recording medium that has excellent adhesion between the protective layer and the magneto-optical recording layer and does not cause a head crash can be obtained.

[0004]

However, in the magneto-optical recording medium disclosed in JP-A-6-259826 and JP-A-7-6418, a recording / reproducing method used in surface contact with the magneto-optical recording medium is used. However, since sufficient lubricity with the head is not obtained, there has been a problem that a head crash occurs.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a magneto-optical recording medium which has sufficient lubrication and does not cause a head crash.

[0006]

According to a first aspect of the present invention, there is provided a magneto-optical recording medium comprising: an inorganic enhancing layer, a magneto-optical recording layer, an inorganic protective layer, and an organic protective layer formed sequentially on a transparent substrate. In the magneto-optical recording medium, the organic protective layer is mixed with a mixture of epoxy novolak acrylate, ethoxylated trimethylolpropane triacrylate and dipropylene glycol diacrylate at a predetermined ratio to the total amount of the mixture. It is characterized in that it is obtained by curing an ultraviolet curable resin comprising 1α-hydroxyketone, α-amineketone, and a polyether-modified silicone polymer. The second invention is claim 1
The magneto-optical recording medium according to claim 1, wherein the organic protective layer has a total weight ratio of the epoxy novolak acrylate, ethoxylated trimethylolpropane triacrylate and dipropylene glycol diacrylate of 100% by weight, and the organic protective layer has a weight percentage of 40% by weight. A mixture of epoxy novolac acrylate, 10 to 60% by weight of the ethoxylated trimethylolpropane triacrylate and 0 to 50% by weight of the dipropylene glycol diacrylate, and 2% by weight, based on the total amount of the mixture,
It is characterized by comprising α-hydroxyketone, 2% by weight of the α-amine ketone, and 4% by weight of the polyether-modified silicone polymer. According to a third aspect of the present invention, there is provided an inorganic enhancement layer sequentially formed on a transparent substrate, a magneto-optical recording layer,
In a magneto-optical recording medium comprising an inorganic protective layer and an organic protective layer, the organic protective layer comprises a mixture of epoxy novolac acrylate, ethoxylated trimethylolpropane triacrylate and dipropylene glycol diacrylate, and the total amount of this mixture. And a UV curable resin composed of a methylphenylglyoxyester mixed at a predetermined ratio and a polyether-modified silicone polymer. According to a fourth aspect of the present invention, in the magneto-optical recording medium according to the third aspect, the organic protective layer has a total weight ratio of the epoxy novolac acrylate, ethoxylated trimethylolpropane triacrylate and dipropylene glycol diacrylate of 100% by weight. 40% by weight of the epoxy novolak acrylate, 10 to 60% by weight of the ethoxylated trimethylolpropane triacrylate and 0 to
A mixture comprising 50% by weight of the dipropylene glycol diacrylate, 4% by weight of the methylphenylglyoxyester based on the total amount of the mixture, and 4% by weight of the polyether-modified silicone polymer. It is characterized by.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A magneto-optical recording medium according to an embodiment of the present invention will be described with reference to the drawings and tables. First of all,
A first embodiment of the present invention will be described with reference to FIGS. 1 to 3 and Tables 1 and 2. FIG. 1 is a sectional view showing a magneto-optical recording medium according to a first embodiment of the present invention. FIG. 2 is a diagram showing the weight ratio dependence of the frictional force between ethoxylated trimethylolpropane triacrylate and dipropylene glycol diacrylate in the first embodiment of the present invention.
FIG. 3 is a diagram illustrating a relationship between a dynamic friction coefficient and a load according to the first embodiment of the present invention. Table 1 is a table showing the frictional force and the dynamic friction coefficient of various samples in which the type of the lubricant was changed.
Table 2 is a table showing the frictional force and the dynamic friction coefficient of various samples in which the kind of the oligomer was changed.

As shown in FIG. 1, a magneto-optical recording medium 1 according to a first embodiment of the present invention includes a transparent substrate 2 on which pits and grooves are formed by injection molding, photopolymer molding, or the like. And a 50 nm to 100 nm thick inorganic enhanced layer 3 made of SiN or SiO ₂ and a 30 nm thick made of TbFeCo etc.
100 nm magneto-optical recording layer 4, 50 nm to 100 nm thick inorganic protective layer 5 made of SiN, SiO ₂ or the like, a mixture of oligomer, ethoxylated trimethylolpropane triacrylate and dipropylene glycol diacrylate, and a mixture thereof Is obtained by curing an ultraviolet curable resin comprising 1α-hydroxyketone, α-amineketone and a lubricant compounded in a predetermined ratio with respect to the total amount of
And an organic protective layer 6 of 10 μm.

[0009] 1α-hydroxyketone and α-amineketone are converted to the oligomer,
It is a photoinitiator that makes ethoxylated trimethylolpropane triacrylate and dipropylene glycol diacrylate into polymers. Lubricity when the recording / reproducing head is operated in surface contact with the magneto-optical recording medium 1 is obtained by the lubricant in the organic protective layer 6 oozing out on the surface of the magneto-optical recording medium 1. It has been experimentally confirmed that the frictional force between the head and the magneto-optical recording medium should be 0.8 mN or less so that the head can perform recording and reproduction without causing head crash. For this reason, this frictional force needs to be 0.8 mN or less.

In the following, the lubricity when the type of the lubricant, the type of the oligomer and the weight ratio of the mixture in the organic protective layer 6 were changed was examined. First, samples having different types of lubricants were prepared, and the lubricity was examined. As the kind of the lubricant, a polyether-modified silicone polymer, an alkyl-modified silicone polymer, an acrylic copolymer silicone polymer, a polyester acrylic-based silicone polymer, a fluoropolymer, and silicon nitride were selected. Each sample had a thickness of 1.
A 50-nm thick SiN is formed on a 2 mm polycarbonate resin substrate, and various lubricants are formed on the SiN. The lubricity was determined by using a 2.2 × 3.3 mm surface contact head made of calcium titanate and sliding the surfaces of these samples at a linear velocity of 1.5 m / s and a load of 5 g for 30 minutes. It was evaluated by examining the friction force and the dynamic friction coefficient. Table 1 shows the results.

[0011]

[Table 1]

As shown in Table 1, when a polyether-modified silicone polymer was used as the lubricant, the coefficient of kinetic friction was the smallest, the frictional force was 0.8 mN or less, and no head crash occurred. Thus, it was found that when the polyether-modified silicone polymer was used as the lubricant, good lubricity was obtained.

Next, each sample of the organic protective layer 6 in which the kind of the oligomer was changed was prepared, and its lubricity was examined. Epoxy novolak acrylate, epoxy acrylate, aliphatic urethane diacrylate, silicone acrylate, and modified polyether acrylate were selected as the type of oligomer. Each sample is 1.2m thick
50 nm thick Si on a polycarbonate resin substrate
N is formed, and an organic protective layer 6 in which the type of oligomer is changed is formed on the SiN.

More specifically, the organic protective layer 6 has a total weight ratio of ethoxylated trimethylolpropane triacrylate, dipropylene glycol diacrylate and oligomer of 100% by weight and 30% by weight of ethoxylated trimethylol. Methylolpropane triacrylate, 30
Weight% dipropylene glycol diacrylate, 40
UV curable resin consisting of a mixture of oligomers by weight, 2% by weight of 1α-hydroxyketone, 2% by weight of α-amine ketone, and 4% by weight of a polyether-modified silicone polymer, based on the total amount of the mixture. Is cured. The lubricity was determined by using a 2.2 × 3.3 mm surface contact head made of calcium titanate and sliding the surfaces of these samples at a linear velocity of 1.5 m / s and a load of 5 g for 30 minutes. It was evaluated by examining the friction force and the dynamic friction coefficient. Table 2 shows the results.

[0015]

[Table 2]

As shown in Table 2, when epoxy novolac acrylate was used as the oligomer, the coefficient of kinetic friction was the smallest, the frictional force was 0.8 mN or less, and no head crash occurred. Thus, it was found that when epoxy novolac acrylate was used for the oligomer, good lubricity was obtained.

Next, using a polyether-modified silicone polymer as a lubricant and epoxy novolac acrylate as an oligomer, the epoxy novolak acrylate, ethoxylated trimethylolpropane triacrylate and dipropylene glycol diacrylate are used as main components. Each sample of the organic protective layer 6 in which the weight ratio of the components was changed was prepared, and its lubricity was examined. Each sample is 50 n thick on a 1.2 mm thick polycarbonate resin substrate.
m of SiN was formed, and an organic protective layer 6 containing epoxy novolak acrylate, ethoxylated trimethylolpropane triacrylate, and dipropylene glycol diacrylate as main components and varying the weight ratio of the main components was formed on the SiN. Things.

More specifically, this organic protective film 6 has a weight ratio of 40% by weight of epoxy resin when the total weight ratio of ethoxylated trimethylolpropane triacrylate, epoxy novolak acrylate and dipropylene glycol diacrylate is 100% by weight. Novolak acrylate, 1
A mixture of 0 to 60% by weight of ethoxylated trimethylolpropane triacrylate and 0 to 50% by weight of dipropylene glycol diacrylate, 2% by weight, based on the total amount of the mixture, of 1α hydroxyketone;
It is obtained by curing an ultraviolet curable resin composed of a weight% of α-amine ketone and 4 weight% of a polyether-modified silicone polymer.

The lubricity was measured by using a surface contact head of 2.2 × 3.3 mm made of calcium titanate and sliding the surfaces of these samples at a linear velocity of 1.5 m / s and a load of 5 g for 30 minutes. Evaluation was made by examining the frictional force at that time. The result is shown in FIG. In FIG. 2, the horizontal axis represents the weight ratio between ethoxylated trimethylolpropane triacrylate and dipropylene glycol diacrylate, and the vertical axis represents the frictional force (mN).

As shown in FIG. 2, the frictional force of ethoxylated trimethylolpropane triacrylate was 10-60.
Weight%, dipropylene glycol diacrylate is 0 to
0.8 mN or less in the entire range of 50% by weight, and no head crash occurred. Here, that the weight ratio of dipropylene glycol diacrylate is 0% by weight indicates that the mixture is composed of epoxy novolak acrylate and ethoxylated trimethylolpropane triacrylate.

Next, using a polyether-modified silicone polymer as a lubricant and epoxy novolac acrylate as an oligomer, the above-mentioned main components are 40% by weight of epoxy novolak acrylate, 30% by weight of ethoxylated trimethylolpropane triacrylate and Each sample of the organic protective layer 6 composed of 30% by weight of dipropylene glycol diacrylate was prepared, and the lubricity when a load was applied to the head was examined. The sample is 1.2m thick
50 nm thick Si on a polycarbonate resin substrate
N is formed, and an organic protective layer 6 mainly composed of the above-mentioned weight ratio of epoxy novolak acrylate, ethoxylated trimethylolpropane triacrylate and dipropylene glycol diacrylate is formed on the SiN.

The lubricating property was measured by using a 2.2 × 3.3 mm surface contact head made of calcium titanate and applying a load of 1 to 9 g to the head.
It was slid at 0 m / s and 1.5 m / s for 30 minutes, and evaluated by examining the dynamic friction coefficient at that time. The result is shown in FIG. In FIG. 3, the horizontal axis represents the load, and the vertical axis represents the dynamic friction coefficient. As shown in FIG. 3, the dynamic friction coefficient was as small as 0.06 or less when the load was 2 to 9 g at both the linear velocities of 1.0 m / s and 1.5 m / s, and no head crash occurred. In the case of a load of 1 g, the dynamic friction coefficient is 0.0
8 or more, causing head crash. Load 1g
In this case, it is considered that the head crash occurs because boundary lubrication does not occur.

This is based on the fact that the main components are 40% by weight of epoxy novolac acrylate, 10 to 60% by weight of ethoxylated trimethylolpropane triacrylate and 0 to 60% by weight.
Similar results were obtained when each sample of the organic protective layer 6 composed of 50% by weight of dipropylene glycol diacrylate was prepared. Thus, the organic protective layer 6 whose main component is composed of 40% by weight of epoxy novolac acrylate, 10 to 60% by weight of ethoxylated trimethylolpropane triacrylate and 0 to 50% by weight of dipropylene glycol diacrylate is used. On the other hand, it has been found that in order to slide the head without causing head crash, it is necessary to apply a load of 2 to 9 g to the head.

As described above, when the total weight ratio of epoxy novolak acrylate, ethoxylated trimethylolpropane triacrylate and dipropylene glycol diacrylate is 100% by weight, 40% by weight of epoxy novolak acrylate, 10 to 60% by weight. % Ethoxylated trimethylolpropane triacrylate and 0-50% by weight of dipropylene glycol diacrylate, 2% by weight of 1α-hydroxy ketone and 2% by weight of α-amine ketone, based on the total amount of the mixture. By using the organic protective film 6 obtained by curing an ultraviolet curable resin composed of 4% by weight of a polyether-modified silicon polymer, it is possible to obtain a magneto-optical recording medium 1 having no head crash and having good lubricity. .

The magneto-optical recording medium of the first embodiment of the present invention is used for a magneto-optical recording medium having a low recording density and a low cost, but when the recording density is high, the head is slid smoothly. In order to move the optical recording medium, a magneto-optical recording medium with further improved surface curability is required. Although the cost is higher than the magneto-optical recording medium of the first embodiment of the present invention, in this case, the magneto-optical recording medium of the second embodiment described below is used.

A second embodiment of the present invention will be described with reference to FIGS. FIG. 4 is a diagram showing the weight ratio dependency of the frictional force between ethoxylated trimethylolpropane triacrylate and dipropylene glycol diacrylate in the second embodiment of the present invention. FIG. 5 is a diagram illustrating a relationship between a dynamic friction coefficient and a load according to the second embodiment of the present invention. Table 3 is a table showing the frictional force and the dynamic friction coefficient of various samples in which the kind of the oligomer was changed. The same components as those in the first embodiment of the present invention are denoted by the same reference numerals, and description thereof will be omitted. The magneto-optical recording medium according to the second embodiment of the present invention is a magneto-optical recording medium 1 according to the first embodiment of the present invention, which has methylphenylglyoxyester instead of 1α-hydroxyketone and α-amineketone,
Otherwise, the configuration is the same. Methylphenylglyoxyester is a photoinitiator that polymerizes the oligomer, ethoxylated trimethylolpropane triacrylate and dipropylene glycol diacrylate when irradiated with ultraviolet light.

Hereinafter, similarly to the first embodiment of the present invention,
The lubricity when the type of oligomer and the weight ratio of the mixture in the organic protective layer 6 were changed was examined. First, each sample of the organic protective layer 6 in which the kind of the oligomer was changed was prepared, and its lubricity was examined. Epoxy novolak acrylate, epoxy acrylate, aliphatic urethane diacrylate, silicone acrylate, and modified polyether acrylate were selected as the type of oligomer. In each sample, 50 nm thick SiN was formed on a 1.2 mm thick polycarbonate resin substrate, and an organic protective layer 6 having a different oligomer type was formed on the SiN.

More specifically, the organic protective layer 6 has a weight percentage of ethoxylated trimethylolpropane triacrylate, dipropylene glycol diacrylate and oligomer of 100% by weight, and 30% by weight of ethoxylated trimethylol. Methylolpropane triacrylate, 30
Weight% dipropylene glycol diacrylate, 40
An ultraviolet-curable resin comprising a mixture consisting of oligomers by weight of 4% by weight, methylphenylglyoxyester of 4% by weight and a polyether-modified silicone polymer of 4% by weight based on the total amount of the mixture, is cured. is there.

The lubricity was determined by sliding the surfaces of these samples at a linear velocity of 1.5 m / s and a load of 5 g for 30 minutes using a 2.2 × 3.3 mm surface contact head made of calcium titanate. The evaluation was made by examining the frictional force and dynamic friction coefficient at that time. Table 3 shows the results.

[0030]

[Table 3]

As shown in Table 3, when epoxy novolac acrylate was used as the oligomer, the dynamic friction coefficient was the smallest, and the frictional force was 0.8 mN or less, and no head crash occurred. Also in this case, as in the first embodiment of the present invention, it was found that when epoxy novolac acrylate was used for the oligomer, good lubricity was obtained.

Next, using a polyether-modified silicone polymer as a lubricant and epoxy novolac acrylate as an oligomer, the epoxy novolak acrylate, ethoxylated trimethylolpropane triacrylate and dipropylene glycol diacrylate are used as main components. Each sample of the organic protective layer 6 in which the weight ratio of the components was changed was prepared, and its lubricity was examined. Each sample is 50 n thick on a 1.2 mm thick polycarbonate resin substrate.
m of SiN was formed, and an organic protective layer 6 containing epoxy novolak acrylate, ethoxylated trimethylolpropane triacrylate, and dipropylene glycol diacrylate as main components and varying the weight ratio of the main components was formed on the SiN. Things.

Specifically, this organic protective film 6 has a weight ratio of 40% by weight of epoxy resin when the total weight ratio of ethoxylated trimethylolpropane triacrylate, epoxy novolak acrylate and dipropylene glycol diacrylate is 100% by weight. Novolak acrylate, 1
A mixture of 0 to 60% by weight of ethoxylated trimethylolpropane triacrylate and 0 to 50% by weight of dipropylene glycol diacrylate, 4% by weight, based on the total amount of the mixture, of methylphenylglyoxyester; It is obtained by curing an ultraviolet curable resin composed of a polyether-modified silicone polymer by weight.

The lubricity was measured by using a 2.2 × 3.3 mm surface contact head made of calcium titanate to slide the surfaces of these samples at a linear velocity of 1.5 m / s and a load of 5 g for 30 minutes. Evaluation was made by examining the frictional force at that time. FIG. 4 shows the results. In FIG. 4, the horizontal axis represents the weight ratio of ethoxylated trimethylolpropane triacrylate to dipropylene glycol diacrylate, and the vertical axis represents the frictional force (mN).

As shown in FIG. 4, as in the first embodiment of the present invention, the frictional force was 10 to 60% by weight for ethoxylated trimethylolpropane triacrylate and 0 to 50% by weight for dipropylene glycol diacrylate. Was 0.8 mN or less over the entire range, and no head crash occurred. Here, that the weight ratio of dipropylene glycol diacrylate is 0% by weight indicates that the mixture is composed of epoxy novolak acrylate and ethoxylated trimethylolpropane triacrylate.

Next, using a polyether-modified silicone polymer as a lubricant and epoxy novolac acrylate as an oligomer, the above-mentioned main components are 40% by weight of epoxy novolac acrylate, 30% by weight of ethoxylated trimethylolpropane triacrylate and A sample of the organic protective layer 6 composed of 30% by weight of dipropylene glycol diacrylate was prepared, and the lubricity when a load was applied to the head was examined. The sample is 1.2mm thick
50nm thick SiN on a polycarbonate resin substrate
And an organic protective layer 6 containing, as a main component, the epoxy novolak acrylate, ethoxylated trimethylolpropane triacrylate, and dipropylene glycol diacrylate in the above-described weight ratios.

The lubricating property was measured by using a 2.2 × 3.3 mm surface contact head made of calcium titanate, and applying a load of 1 to 9 g to the head.
It was slid at 0 m / s and 1.5 m / s for 30 minutes, and evaluated by examining the dynamic friction coefficient at that time. The result is shown in FIG. In FIG. 5, the horizontal axis represents the load, and the vertical axis represents the dynamic friction coefficient. As shown in FIG. 5, the dynamic friction coefficient is smaller than that of the first embodiment of the present invention in the entire range where the load is 1 to 9 g at both linear velocities of 1.0 m / s and 1.5 m / s. Did not occur.

This is based on the fact that 40% by weight of epoxy novolak acrylate, 10 to 60% by weight of ethoxylated trimethylolpropane triacrylate and
Similar results were obtained when each sample of the organic protective layer 6 composed of 50% by weight of dipropylene glycol diacrylate was prepared. Thus, the organic protective layer 6 whose main component is composed of 40% by weight of epoxy novolac acrylate, 10 to 60% by weight of ethoxylated trimethylolpropane triacrylate and 0 to 50% by weight of dipropylene glycol diacrylate is used. It has been found that if used, the head can be slid without causing a head crash even when the load applied to the head is light.

As described above, when the total weight ratio of epoxy novolak acrylate, ethoxylated trimethylolpropane triacrylate and dipropylene glycol diacrylate is 100% by weight, 40% by weight of epoxy novolak acrylate, 10 to 60% by weight. % Ethoxylated trimethylolpropane triacrylate and 0-50% by weight of dipropylene glycol diacrylate, 4% by weight of methylphenylglyoxyester, 4% by weight, based on the total weight of the mixture.
The use of the organic protective film 6 obtained by curing an ultraviolet curable resin composed of a polyether-modified silicone polymer of the formula (1) eliminates head crash even when the load applied to the head is light, and further enhances good lubricity with improved surface curability. Thus, the magneto-optical recording medium 1 can be obtained.

[0040]

According to the magneto-optical recording medium of the first aspect of the present invention, the organic protective layer comprises a mixture of epoxy novolac acrylate, ethoxylated trimethylolpropane triacrylate and dipropylene glycol diacrylate, and a mixture of this mixture. Since it is obtained by curing an ultraviolet curable resin composed of 1α-hydroxyketone, α-amineketone, and polyether-modified silicone polymer mixed at a predetermined ratio to the total amount, there is no head crash and good lubricity Can be obtained. Further, according to the magneto-optical recording medium of claim 3 of the present invention, the organic protective layer is composed of a mixture of epoxy novolac acrylate, ethoxylated trimethylolpropane triacrylate and dipropylene glycol diacrylate, and a total amount of this mixture. Good lubrication with no head crash and improved surface curability because UV cured resin consisting of methylphenylglyoxyester and polyether-modified silicone polymer mixed at a predetermined ratio is cured. The magneto-optical recording medium having the property can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a magneto-optical recording medium according to a first embodiment of the present invention.

FIG. 2 is a diagram showing the dependency of frictional force on the mixing ratio of ethoxylated trimethylolpropane triacrylate and dipropylene glycol diacrylate in the first embodiment of the present invention.

FIG. 3 is a diagram illustrating a relationship between a dynamic friction coefficient and a load according to the first embodiment of the present invention.

FIG. 4 is a view showing the weight ratio dependence of frictional force between ethoxylated trimethylolpropane triacrylate and dipropylene glycol diacrylate in the second embodiment of the present invention.

FIG. 5 is a diagram illustrating a relationship between a dynamic friction coefficient and a load according to a second embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Magneto-optical recording medium, 2 ... Transparent substrate, 3 ... Inorganic enhancement layer, 4 ... Magneto-optical recording layer, 5 ... Inorganic protective layer, 6 ... Organic protective layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) C09D 4/06 C09D 4/06 5/00 5/00 Z F term (reference) 4J011 AA05 BA03 BA04 DA04 FA07 PA27 PA36 PA90 PA99 PB30 PC02 QA12 QA24 QB22 RA08 RA10 SA61 UA01 VA01 WA02 4J026 AB19 AB44 AC16 BA28 BA30 BA50 BB03 BB04 DB05 FA04 GA01 GA07 GA08 4J027 AE03 BA19 BA26 CA10 CA25 CA29 CC05 CD08 4J038 DL032 FA151 FA151 FA251 FA151 FA251 5D075 EE03 FG04

Claims (4)

[Claims] 1. A magneto-optical recording medium comprising an inorganic enhancing layer, a magneto-optical recording layer, an inorganic protective layer, and an organic protective layer formed sequentially on a transparent substrate, wherein the organic protective layer is an epoxy novolac acrylate. ,
It is composed of a mixture of ethoxylated trimethylolpropane triacrylate and dipropylene glycol diacrylate, 1α-hydroxyketone mixed at a predetermined ratio with respect to the total amount of the mixture, αamineketone, and a polyether-modified silicone polymer. A magneto-optical recording medium obtained by curing an ultraviolet curable resin. 2. The organic protective layer according to claim 1, wherein the total weight ratio of the epoxy novolak acrylate, ethoxylated trimethylolpropane triacrylate and dipropylene glycol diacrylate is 100% by weight. , 10-6
A mixture of 0% by weight of the ethoxylated trimethylolpropane triacrylate and 0 to 50% by weight of the dipropylene glycol diacrylate, 2% by weight, based on the total amount of the mixture, of 1α hydroxyketone; 2. The magneto-optical recording medium according to claim 1, comprising the α-amine ketone in an amount of 4% by weight and the polyether-modified silicon polymer in an amount of 4% by weight. 3. A magneto-optical recording medium comprising an inorganic enhancement layer, a magneto-optical recording layer, an inorganic protective layer, and an organic protective layer which are sequentially formed on a transparent substrate, wherein the organic protective layer is an epoxy novolac acrylate. ,
UV curing of a mixture of ethoxylated trimethylolpropane triacrylate and dipropylene glycol diacrylate, methylphenylglyoxyester mixed at a predetermined ratio to the total amount of the mixture, and a polyether-modified silicone polymer A magneto-optical recording medium obtained by curing a resin. 4. The organic protective layer according to claim 1, wherein the total weight of the epoxy novolak acrylate, ethoxylated trimethylolpropane triacrylate and dipropylene glycol diacrylate is 100% by weight. , 10-6
A mixture of 0% by weight of the ethoxylated trimethylolpropane triacrylate and 0 to 50% by weight of the dipropylene glycol diacrylate, and 4% by weight of the methylphenylglyoxyester based on the total amount of the mixture; 4. A magneto-optical recording medium according to claim 3, comprising 4% by weight of said polyether-modified silicon polymer.