JPS62212602A - Transparent base material - Google Patents

Abstract

PURPOSE:To obtain a transparent base material which obviates the exfoliation of a medium layer even if the material is used for a long period of time by providing an aluminum oxide layer on the surface of a molding obtd. by molding and curing a compsn. consisting of an acetal compd. and mercapto compd. CONSTITUTION:The aluminum oxide layer is formed on the surface of the molding obtd. by during the compsn. consisting of the compd. having at least two unsatd. cycloacetal groups per molecule and the compd. having least two mercapto groups per molecule. The aluminum oxide layer exhibits extremely good affinity to said molding and has also the good adhesiveness with the medium layer which is provided on the base material and consists of Al, etc. The transparent base material is thereby made to be satisfactorily and tightly adhered with the medium layer consisting of the Al, etc., and the optical disk or the like consisting of such transparent base material is free from the generation of the exfoliation of the medium layer or the like even when the disk is used for a long period of time.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to optical information recording discs, particularly V5"A discs, audio discs, etc. that record and reproduce information such as video records and 8 voices using light. The present invention relates to a transparent base material that can be suitably used as a substrate material for optical disks such as optical memory disks.

(Prior art and its problems) Optical discs have the advantage of being able to reproduce information in a non-contact manner, have a long lifespan, and are capable of recording large volumes of GF3 (gigabyte) class. Research and development is underway.

Conventionally, this type of optical disk has been constructed by providing a layer made of a medium such as aluminum 1) on a base material made of a transparent resin such as polymethacrylate resin or polycarbonate resin.

However, such conventional optical discs lose N over time.
There was a problem in that the adhesion between the medium layer and the base material deteriorated, and the N medium layer was likely to peel off when used for a long period of time.

For this reason, substrates have been provided with layers of silicon oxide (S12), zinc sulfide (znS'), titanium III chloride (L02), etc. on the surface of the substrate, but in all cases,
There was some dissatisfaction with not being able to adequately address the above issues.

(Means for Solving the Problem) As a result of extensive research in order to solve the above problems, the present inventors found that an aluminum oxide layer is formed on the surface of a molded product obtained by curing the following composition. The present inventors have discovered that the above-mentioned problems can be solved by using a transparent base material formed with the above-mentioned transparent base material, and have accomplished the present invention.

First, the composition used for the transparent substrate of the first invention is a compound containing at least two unsaturated cycloacetal groups per molecule (hereinafter referred to as an acecool compound (A)).
(hereinafter abbreviated as mercapto compound (B)) and a compound having at least two mercapto groups per molecule (hereinafter abbreviated as mercapto compound (B))
It consists of.

Further, the curable composition used for the transparent substrate of the second invention further contains at least two acryloyl groups and/or A compound having a methacryloyl group (hereinafter abbreviated as (meth)acryloyl compound (C)) is added.

Hereinafter, the transparent base material of the present invention will be explained in detail.

The transparent substrate of the present invention has an aluminum oxide layer formed on the surface of a molded body made of a predetermined composition.

This aluminum oxide layer is for improving the adhesion of a medium layer such as N provided on the base material. This aluminum oxide layer has extremely good affinity with the molded article made of the composition described below, and also has good affinity with the N medium layer.

The thickness of this aluminum oxide layer is 80 nm to 1100 nm.
It is desirable that it be about 00n. If the thickness is less than 80 nm, the aluminum oxide layer cannot be uniformly formed on the surface of the molded body, and the adhesion of the medium layer such as N tends to be uneven.

Moreover, if the thickness exceeds 110,000 nm, no improvement in the adhesion of the N or other medium layer can be expected even if an aluminum oxide layer is formed beyond that, and furthermore, the productivity of the base material is reduced.

Examples of means for forming such an aluminum oxide layer on the surface of the molded product include a vacuum Wi deposition method and a sputtering method.

A known method such as an ion beam method can be applied.

Next, a method of forming an aluminum oxide layer by these means will be described.

1) Vacuum evaporation method This is a method in which high-purity alumina is heated and melted in a vacuum by resistance heating or electron gun heating, and then evaporated to form an aluminum oxide layer on the molded body.

The degree of vacuum is 10' to 10-'torrt' which is good.

In addition, in order to obtain a good quality film, it is necessary to introduce 1 while introducing 02.
It is desirable to perform this in an atmosphere of 0'torr.

The film formation rate is preferably about 100 to 5000 people/sin, and about 500 to 2000 people/win.

If the film formation rate is too high, the film may become opaque or non-uniform, which is not preferable. Also, if the speed is slower than 1008/■in, productivity will be poor or whitening will occur. This vacuum evaporation method has the advantage that it can be performed using simple equipment.

2) Sputtering method: Place the molded body and target opposite each other in a vacuum, and then
Generate plasma. In this method, an electric field is applied between the molded body and the target, and ^r+ knocks out aluminum oxide in the target, thereby attaching a film to the molded body. This method has the advantage that strong adhesion can be obtained and the temperature of the molded body does not rise too much. The ultimate degree of vacuum is in the range of 10-7 to 10 torr, and the concentration of Ar gas is in the range of 10-4 to 10-5 torr. The film formation speed is
It is sufficient if it is 50 to 500 people/win.

3) Ion beam method In this method, alumina is melted and evaporated by resistance heating or electron gun heating in a vacuum, and is further turned into plasma during the process. By applying ff1W between the molded body and the crucible, the vapor deposition material ionized in the plasma is accelerated by the electric field and collides with and adheres to the molded body. Therefore, this method has the characteristic that strong adhesion of the aluminum oxide film can be obtained. Furthermore, before forming the aluminum oxide film here, it is also possible to subject the molded body to a pretreatment such as plasma etching treatment, ion or electron beam treatment, or the like.

Next, the composition forming the transparent straw material molding of the present invention will be explained in detail.

First, each component of the composition will be explained.

(A) Acetal compound (A) The acetal compound (A) which is the first component of the composition used in the first and second inventions is (unsaturated dioxane type) and/or ( It is an unsaturated cycloallotal compound having at least two unsaturated cycloacetal groups in one molecule, represented by the following unsaturated dioxolane type.

Examples of the acetal compound (A) suitably used in the transparent substrate of the present invention include the following compounds (i+ to V).

Diarylidene pentaerythritol, triarylidene sorbitol, diarylidene-2, 2, 6, 6-titramethylolcyclohexynone, or 21 compounds thereof.

(i) (a>diarylidenepentaerythritol and (
or) diarylidene-2, 2, 6, 6-titramethylolcyclohexanone and (b) ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1, 3-butanediol, 1, 6
-Hexanediol, polyethylene glycol, hydrogenated bisphenol A, bisphenol to -ethylene oxide adduct, bisphenol A-propylene oxide adduct, trimethylolpropane, trimethylolethane, pentaerythritol, dipentaerythritol.

Ethylene oxide adduct of phthalic acid, isophthalic acid and terephthalic acid 9 molecules f11. Terminal water M of 1500 or less
Polyols such as at-containing polyesters.

(C) dithioglycol, dibentenedimel butane,
Water per molecule, such as polythiols such as ethylcyclohexyl dimercaptan and 1,6-hexane dimercaptan, thioglycolic acid, β-mercaptopropionic acid, or ester compounds obtained by reacting mercaptosuccinic acid with the above polyols. I! A compound containing a total of two or more groups and (or) mercapto groups, (
d) Phenol, cresol and novolak obtained by formalin condensation of these, bisphenol F,
Phenols such as bisphenol A.

(e) Arylsulfonamides such as benzenesulfonamide, 0-toluenesulfonamide, P-toluenesulfonamide, chlorobenzenesulfonamide, or (f) a reaction product with a mixture thereof.

(To) Monoallylidene trimethylolpropane and/or monoallylidene trimethylolethane and isocyanate compounds such as tolylene diisocyanate, polyalkylene allyl isocyanate, metaphenylene diisocyanate, xylylene diisocyanate, hexylimethylene diisocyanate, isophorone diisocyanate, etc. reaction product.

(f) Monoallylidene trimethylolpropane and/or monoallylidene trimethyloleethane with succinic anhydride, maleic anhydride, itacone II anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic acid Additive hemi-Nisderide with anhydride.

(V) Addition half-esterified product of monoallylidene trimethylolpropane and/or monoallylidene trimethyloleethane with carboxylic acid anhydride, polyglycidyl ether type epoxy compound, phthalic acid, adipic acid, dimer acid, etc. A compound obtained by reacting with an epoxy compound such as a glycidyl ester type epoxy compound.

(B) Mercapto Compound The mercapto compound (B) used as the second component of the composition used in the first and second inventions refers to at least two mercapto compounds per molecule!・It is an aliphatic or aromatic polymercaptan with U.

Examples of the mercapto compound ([3)] suitably used in the composition of the present invention include the compounds shown in the following (I) to (V).

(i) Dibentenedimerbutane, Nibu-RusikOhexyldimercaptan, 1,6-hexanedimercaptan.

■An ester compound of a mercapto compound having a carboxyl group and a polyhydric alcohol. Examples of the mercapto compound having a carboxyl group include thioglycolic acid, β-mercap]propionic acid, and mercaptosuccinic acid. Further, examples of the polyhydric alcohol include pentaerythritol, dipentaerythritol, trimethylolpropane, and trimethylolethane.

(to) 1 water at the carbon atom in the β-position relative to the mercapto group
lIl! Compounds with groups.

(f) A compound obtained by the reaction of epoxy resin and hydrogen sulfide.

(V) A compound obtained by reacting an epoxy resin with thioglycolic acid.

(C) (Meth) Acryloyl Compound The (meth) acryloyl compound (C) which is the third component of the composition used in the invention of cylinder 2 means a total of at least two 7-acryloyl groups per molecule and/or Various compounds can be used as long as they have a methacryloyl group and are copolymerizable and uniformly mixed with the acetal compound (A) and mercapto compound ([3)].

Such compounds include bisphenol compounds (
C-1), triazine compounds (C-2), and other compounds (C-3). Among these, bisphenol compound (C-1).

Triazine compounds (C-2) and the like are preferable because the composition containing them has particularly excellent heat resistance and water resistance.

These compounds will be explained below.

Bisphenols (C-1) suitable for use in the present invention are bisphenols having a total of at least two acryloyl groups and/or methacryloyl groups per molecule.

Examples of such bisphenol compounds (C-1) include those represented by the following formula (1).

(R1+7(+X→Rz).2−−−−−(+)(1
), where n I +n2 is an integer from 1 to 3.

In formula (1), X has a structure represented by C such as formulas (2) to (7).

CI CH3C/ Here, Y in formula (2) has a structure shown in formulas (8) to (16), etc.

CH3 CH3 -CH2----(9) -C------
(10) CH3 0CH3 CH3H3CCH3 Furthermore, in formula (1), RI -R2 includes a structure represented by formula (17).

R30 Here, in formula (17), R3 and R4 are hydrogen (H).

Medyl 13 (MO), ethyl group (Et) and its one-halogen atom substituted product. Further, m is an integer from 0 to 6.

Each of the above compounds can be used alone or as a mixture of 62 or more types.

1 sl-'A ・1 A triazine compound (C-2) suitable for use in the present invention has at least one [・riazine ring per molecule, and at least -b 512 It is a compound having acryloyl groups and/or methacryloyl groups. Examples of such compounds include compounds represented by the following formula (18), or compounds obtained by oligomerizing these with formalin, polyhydric alcohol, ethylene oxide, etc.
Can list things.

(18) In the formula, X, Y, and Z are hydrogen, alkyl 5, alkyl 1 nisyl group, alkoxyl? Krylic modified, provided that R1.~R2G, hydrogen. an aliphatic alkyl group such as a methyl group, an ethylene group, a propyl group, an aromatic alkyl group such as a benzyl group, or G;1(n-0 to 4,
-hydrogen or alkyl group)? show.

Typical examples of this triazine compound (C-2) are (1) N, N'-bis(meth)acryloylmethyl-N, N', N'', N''-tetrakismethoxaldimethylmelamine, N, N, N', N"-detrakis (
meth)acryloylmethyl-NZ, NIJ-bisethoxymedylmef4no, (2) N, N, N', N', N'', N''-hexakis (2-(meth)acryloylethoxymethyl)
Melamine, (3) 2,4-bis[[N,N-bis[
(2-(meth)acryloylethoxy)ethoxymethyl 1]amino 1-6-nitoxy 1.3.5-triazine, (4) 2.4-bis[p-(2-(meth)acryloylethoxy)phenyloxy] -6-[[14,
M-bis[(2-(meth)acryloylethoxy)ethoxymethyl 1]amino]-1,3,5-triazine,
(5) 2.2-bis[4-[[N,N', N"-trismethoxymethyl-N', N"-(2-(meth)acryloylethoxy)methyl]melaminyloxy]phenyl]propane, etc. be able to.

In addition, as polyhydric alcohols used for oligomerization,
Examples include ethylene glycol, diethylene glycol, propylene glycol, 1,3-butanediol, 1,6-hexanediol, hydrogenated bisphenol A, trimethylolpropane, pentaerythritol, ethylene oxide adducts of phthalic acid, isophthalic acid, and terephthalic acid. It will be done.

Note that the number of functional groups per triazine ring in the molecule is not limited at all as long as it is 2 or more, but considering the balance between the water absorption effect due to ester bonds and the improvement in heat resistance due to increase in crosslink density, The number of functional groups per 111 triazines in one molecule is preferably within the range of 4 to 6.

b - This third component is a (meth)acryloyl compound (C
) Other suitable compounds (C-3>) include the following.

Ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate, propylene glycol diacrylate 1-, polypropylene glycol diacrylate.

Butylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythryl triacrylate, diglycidyl bisphenol A diacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate-1~, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, polypropylene Glycol dimethacrylate, propylene glycol dimethacrylate, butylene glycol dimethacrylate, trimethylolpropane triacrylate, pentaerythritol trimethacrylate, diglycidyl bisphenol A dimethacrylate, etc.

(D) Other additives The composition used in the transparent base material of the present invention includes not only various initiators and sensitizers, but also antioxidants, stabilizers, mold release agents, dyes, antistatic agents, Anti-fog agent.

Additives such as a surfactant, a leveling agent, a mixing agent, and an ultraviolet absorber can be added as necessary.

In addition, an acetal compound (A), a mercapto compound (B), (
Any reactive monomer or oligomer can be added as long as it is copolymerizable with the meth)acryloyl compound (C) and is uniformly mixed therewith.

Technique 1 The blending ratio of each of the above components is not particularly limited, but is preferably blended within the following range.

First, it is desirable that the blending ratio of the acetal compound (A) and the mercap (- compound (B) is about 1:1 to 0.5 in equimolar ratio.Blend of the acetal compound (Δ)) If the amount of mercapto compound (B) is too large, it takes a long time to cure and the molded product is likely to become uneven.Also, if the amount of mercapto compound (B) is extremely large, the resulting molded product may be unpleasant. Inconveniences arise in that the product has an odor and physical properties such as hardness are deteriorated.

In addition, in order to obtain a curable resin, the number of unsaturated cycloacetals per molecule of the acetal compound (A) and the number of mercaps per molecule of the mercapto compound (B) must be determined.
- The total number of groups must be 4 or more, preferably 5 or more.

The blending ratio of the (meth)acryloyl compound (C) used in the second invention is not particularly limited, but if the amount used is too large, the resulting molded product will have too high hardness and become brittle. Furthermore, if too little ω is used, the desired heat resistance cannot be obtained. For these reasons, the blending ratio of the (meth)acryloyl compound (C) is 0.2 to 6.3 equivalents, more preferably 0.5 to 5 equivalents, per equivalent of the acetal compound (A). .4 It is desirable to be on duty.

(1) Molding method There is no particular limitation to the manufacturing method for manufacturing an information recording disk such as a disk substrate from a composition consisting of the above-mentioned components, but a casting method is convenient.

For example, an uneven information recording section such as information bits (protrusions) or tracking grooves is formed on a glass or gold hole plate using a method such as a photoresist method, and based on this, a reproduction mold for molding is made using polynisdel etc. (Standby)
A thin metal film is coated on the surface of the stamper, and the above composition, which is liquid when heated at room temperature or under a specific temperature condition, e.g. 100°C or less, is poured into the mold. After it has spread to every corner of the mold, it is cured by heating and/or irradiation with high-energy radiation, and after curing, it is removed from the mold to produce a disk substrate. When the mold is removed after curing, fine irregularities from the mold are found on the substrate surface. It is also possible to make a substrate by injecting the composition between two glass plates having uneven parts, irradiating the composition with high-energy rays across the glass plates, and removing the composition after curing.

As a method for curing this composition, first, the above-mentioned compounds (A), (B), and (C) are uniformly mixed in a predetermined ratio. This mixture is then applied to, for example, glass, ceramic,
It is injected into a mold of a specified shape made of plastic, rubber, etc., and cured using the following method.

(1) Method of irradiating active energy rays This method is
This is a method of curing the composition by irradiating it with active energy rays such as gamma rays, X-rays, ultraviolet rays, and electron beams.

The irradiation energy is generally 0.01 J/t:4
above, 500 J/ai or less, especially 0
．． It is preferably within the range of 1 to 100 J/ai. If the irradiation energy m is less than 0.01 J/d, the crosslinking reaction will be incomplete and curing will be insufficient. On the other hand, 500 J
/ If irradiation exceeds CIi, a part of the resulting cured product (resin) will deteriorate or become colored, making it impossible to obtain a good information recording disc.

The irradiation may be divided into two or more times or may be performed at once. If necessary, please refer to JP-A-58-175877.
Additives such as photosensitizers and stabilizers listed in Japan may be added. This method is described in Japanese Patent Application Laid-Open No. 59-860.
No. 01 and Japanese Patent Application Laid-open No. 59-89330.
It is described in detail in the book.

(2) Method using heat When curing the composition using heat, the heating temperature is:
Although it varies depending on whether or not a polymerization initiator is used, their type and blending ratio, the temperature is usually V. If the heating temperature is lower than room temperature, the curing time will be longer, resulting in poor productivity. On the other hand, if the temperature exceeds 300°C, there will be a problem of deterioration due to heat.

In addition, the heating time depends on the temperature and whether or not a polymerization initiator is used.
Although it varies depending on the type and usage ratio, it is generally 0.1 to 100 hours, and particularly preferably 1 to 20 hours.

By using a polymerization initiator, curing time can be shortened. In this case, if the amount of polymerization initiator used is too large, the resulting cured product may be colored or become brittle, which is not preferable. Therefore, considering the balance between the physical properties and productivity of the cured product obtained, the use of a polymerization initiator is
@ 51 parts to 10 parts by weight or less, usually 5 mff 1 part or less.

Examples of the polymerization initiator suitably used here include those described in Tokubetsu No. 1 No. 1 Sho 55-105201.

The above method of irradiating with active energy rays and the method using heat can also be used in combination.

(Function) The transparent substrate of the present invention has an aluminum oxide layer formed on the surface of a molded body made of a predetermined composition.

This aluminum oxide layer shows extremely good affinity with the molded article made of the specific composition used in the present invention.

Furthermore, this aluminum oxide layer also has good adhesion to the medium layer made of N or the like provided on II.

Therefore, the transparent base material of the present invention allows a medium layer made of N or the like to adhere well, and optical discs etc. made of this transparent base material are free from peeling of the medium layer even after long-term use. It never occurs.

In the above explanation, only the transparent base material in which the aluminum oxide layer is provided on the surface of the molded body is shown, but the transparent base material of the present invention is not limited to this, and if necessary, the transparent base material may be formed on the aluminum oxide layer. Additionally, an intermediate layer made of zirconium oxide or the like may be provided.

(Example) Hereinafter, the transparent base material of the present invention will be explained in more detail according to Examples.

Example 1 Diarylidene pentaerythritol 21.21;l was converted to pentaerythritol tetrathioglycolate 21.21; h and reacted at 50°C for 30 minutes with stirring. next,
To this, 80 g of N,N',N''-1-lis(acryloylmethyl)N,N',N''-tris(methoxymethyl)melamine, 35.2 g of pentaerythritol tetraacrylate and 0.4 g of pencil 1 non were added, A curable composition was obtained by stirring until uniform.

This curable composition was poured into a transparent mold, and a 3KW Mekl halide lamp was used to heat the curable composition from a distance of 15CI11 on both sides at 100°C.
411 is irradiated for seconds and polymerized to produce a uniform, colorless and transparent plate.

Place this plate into a vacuum evaporation device and achieve an ultimate vacuum of 2x l.
After degassing to Q-6Lorr, 1O-4L of Mi gas
Aluminum oxide (Mz03) was vapor-deposited while the aluminum oxide (Mz03) was injected. The deposition rate was 200 people/min, and the film thickness was 2
There were 000 people.

Further, an aluminum layer was formed thereon by the vacuum brown sugar method. The number of people in the M class was 5,000.

Hold the epoxy resin on top of this MwA! ll was formed and used as a sample.

Example 2 Example 1 and 4.4' bisphenol A diacrylate 60 (7 A sample was prepared that differed only in that 40q of trimethylolpropane triacrylate was used instead of pentaerythritol tetraacrylate.

Example 3 Diarylidene 2,2,6,6. 30g of tetramethylolcyclohexanone and 1.1,1. 20 g of l-ristyrolpropane trithioglycolate was added and reacted at 50°C for 30 minutes. Add trimethylol to this
50 a of coban triacrylate was added, and further 0.12 g of azobisisobutyronitrile was added, and the mixture was stirred until homogeneous to obtain a composition. Thereafter, the composition was poured into the mold used in Example 1, and the composition was placed in a constant temperature bath at 70°C for 30 minutes.
Heat for 1 minute, raise the temperature at 10℃/hr, and heat at 90℃ for 3 hours.
The mixture was heated at 120° C. for 1 hour to complete polymerization, and a colorless and transparent molded product was obtained.

Next, using a DC magnetron sputtering device,
An aluminum oxide film was formed with an argon concentration of 1.5×10° 3 torr and a distance of 151 mm between the target and the compact. The film formation rate was 200 people/sin, and the film thickness was 1900 people/sin. Furthermore, a zirconium oxide film was formed on this. The film formation rate of this zirconium oxide was 300 people/1n, and the film thickness was 2100 people/1n.

On top of this zirconium oxide film, an additional 5,000 aluminum films were formed. Next, a protective layer of the same 1-boxy resin as in Example 1 was formed, and a layer 1e' was formed.

Comparative Example 1 A sample that differs from the sample of Example 1 in that an aluminum layer was directly formed on the molded body without providing an aluminum oxide layer.

Comparative Example 2 A sample different from the sample of Example 1 in that a zirconium oxide layer was formed instead of aluminum oxide, and an aluminum layer was formed thereon.

Comparative Example 3 A sample different from the sample of Example 1 in that 1 m of tantalum oxide (Ta20s) was formed instead of aluminum oxide, and an aluminum layer was formed on it.

Comparative Example 4 The order of the aluminum oxide layer and the zirconium oxide layer was reversed from that of the sample of Example 2 to avoid forming the zirconium oxide layer, and then an aluminum oxide layer was formed, and an aluminum oxide layer was formed on it. The difference is in what you did.

Comparison @5 An aluminum oxide layer and an aluminum layer were formed on a polycarbonate resin injection molded product in the same manner as in Example 1. Comparison PA6 An aluminum oxide layer and an aluminum layer were formed on a polymethyl methacrylate resin injection molded product in the same way as in Example 1. Comparative Example 7 100 g of CR-39 monomer manufactured by PPG was added 1PP3. O
Q was added and uniformly dissolved. After pouring this material into the same glass mode as in Example 1, it was held at 38°C for 15 hours, then the temperature was raised to 60°C over 3 hours, and the temperature was raised to 60°C for 2 hours at 60°C.
After being kept open for 2 hours, the mixture was returned to room temperature over 2 hours, and then annealed at 115° C. for 1 hour to obtain a molded article.

An aluminum oxide layer and an aluminum layer were formed on this molded body in the same manner as in Example 1.

Note that in Comparative Examples 1 to 7, a protective film made of epoxy resin was formed in the same manner as in the sample of Example 1.

The initial T! 1! We carried out a weather test.

The weather resistance test was conducted by exposing the sample to a sunshine weather meter at 200 hours and then examining the adhesion.

Adhesion test is Ho:! 11g! Cut 100 1#I square squares on the surface with a knife and firmly stick cellophane adhesive tape (■Cellotape made by Nichiban) [Peel off suddenly in a 190 degree direction, and show the percentage of squares that were not peeled off.

In addition, HD T , water absorption, birefringence 1 of the obtained sample
Surface hardness, solvent resistance, Izod 1-impact value 1 reflectance were measured.

3°1 Tested according to ASTM D-648 method.

The load m was 66 psi.

i Wet and soil ASTM D-570 method, 23
It was tested by immersing it in water at ℃ for 24 hours.

The birefringence at each point was measured using a one-plate automatic ellipsometer while rotating the disk molded body. The light source is 1.Ic-N
The e-laser has a wavelength of 632.8n-. Measured values indicate double bath values. 1a refraction is the average of the absolute values of retardation and is expressed in nm.

1 plate of beans It shows the light transmittance at a wavelength of 7g0n.

K-sara-sato-sara By Percoll hard method.

It was tested according to ASTM D-256 using a V-notch.

The results are shown in Table 1.

(Effects of the Invention) The transparent substrate of the present invention molds and cures a composition consisting of an acetal compound and a mercapto compound, or a composition consisting of an acetal compound, a mercapto compound, and a (meth)acryloyl compound. Since the aluminum oxide layer is provided on the surface of the molded body obtained, a medium layer made of M or the like can be tightly adhered to this base material. Therefore, according to the transparent base material of the present invention, it is possible to obtain an optical disk or the like that has a long life and excellent durability, and does not cause peeling of the medium layer even when used for a long period of time under severe filling conditions.

Furthermore, as can be confirmed from the results in Table 1, the transparent base material of the present invention is made of polycarbonate resin.

Heat resistance, water absorption, 1 refraction, and hardness compared to base materials made of polymethacrylic acid resin, CR-39, etc.

It also has excellent physical properties such as impact resistance.

Claims (4)

[Claims] (1) Molding obtained by curing a composition consisting of [a] a compound having at least two unsaturated cycloacetal groups per molecule and [b] a compound having at least two mercapto groups per molecule A transparent base material characterized by having a layer made of aluminum oxide formed on the surface of the body. (2) [a] A compound having at least two unsaturated cycloacetal groups per molecule, [b] a compound having at least two mercapto groups per molecule, and [c
] A layer made of aluminum oxide is formed on the surface of a molded product obtained by curing a composition made of a compound having a total of at least two acryloyl groups and/or methacryloyl groups per molecule. Transparent base material. (3) A compound having a total of at least two acryloyl groups and/or methacryloyl groups per molecule [c
] is a bisphenol having a total of at least two acryloyl groups and/or methacryloyl groups per molecule. (4) Compounds having a total of at least two acryloyl groups and/or methacryloyl groups per molecule [c
] is a compound having a total of at least two acryloyl groups and/or methacryloyl groups per molecule and at least one triazine ring. sexual base material.