JPS6198734A - Curable composition - Google Patents

Abstract

PURPOSE:To provide a composition consisting of a compound containing reactive unsaturated group and a compound containing mercapto group, and giving an excellent transparent disk having high surface strength, high crack resistance, extremely low hygroscopicity and stable refractive index by casting. CONSTITUTION:The objective composition is composed of (A) a compound having >=2 reactive unsaturated groups in one molecule and (B) a compound having >=2 mercapto groups in one molecule. The component A is e.g. divinylbenzene, ethylene glycol diacrylate, diallyl phthalate, etc., and the component B is e.g. dipentene dimercaptan, ethylcyclohexyl dimercaptan, etc. The equivalent ratio of A/B is (1-10)/1, preferably (1-5)/1.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a curable composition for information recording discs, particularly for recording (writing) and reproducing (reading) information such as video and audio using light. The present invention relates to a curable composition suitable for use in discs such as video discs, audio discs, and optical memory discs.

With the advancement of conventional technology and information society, large amounts of information can be written (
Discs that can be recorded, read, and played are:
There are various types, but in general, information (signals) is recorded on a disk called a disk (this information is read out using a pickup, player, etc., by reflecting a laser beam or other light beam).

The structure of a disc generally consists of a glass or plastic disc substrate (disk), a metal reflective surface made of metal plating such as aluminum, and a plastic protective film (layer) formed on top of that. .

Such disks are produced by, for example, coating a glass or plastic master with photorenost, irradiating it with laser light or the like to make the renost solubilized in a positive type, and insolubilized in a negative type, and then developed. (protrusion)
A signal recording section consisting of the following structure is formed, a metal reflective surface is formed on the surface by metal plating, etc., and a plastic protective film is formed on top of it as necessary, and a mask disc is produced. Molded in large quantities through a process similar to
Get your picture stolen.

Some optical video discs are made by laminating single-sided discs consisting of a substrate, a metal reflective surface, and a plastic protective layer with their i-sides facing inside to form a double-sided disc.

Reading information from a disc is generally performed using a device called a pink amplifier or player, which irradiates a laser beam or other light beam through the surface of the disc to the internal signal recording area such as bits, and changes the intensity of the reflected light. etc.).

In general, discs used for recording and reproducing information need to be transparent in order for radar light to pass through the disc substrate, and must also be optically uniform and , it is important to have excellent dimensional stability.

Conventionally, polymethyl methacrylate and polycarbonate yarn plates have been commonly used as plastic transparent substrates.

However, polymethyl methacrylate substrates have drawbacks such as a lack of heat resistance, a high moisture absorption rate, and large dimensional changes due to moisture absorption.On the other hand, polycarbonate substrates have weak surface strength and are susceptible to scratches. It is easy to mold, has poor moldability, and has drawbacks such as birefringence due to orientation of molecules due to flow during molding.

Problems to be Solved by the Invention An object of the present invention is to eliminate the above-mentioned problems and provide a disk substrate having excellent characteristics.

Further, other objects and novel features of the present invention will become apparent from the description of this specification.

Means for Solving the Problems The present inventors have succeeded in manufacturing an excellent substrate after thoroughly studying the advantages and disadvantages of conventional substrates.

The present invention provides a curable material for information recording discs which contains as essential components a compound having at least two reactive unsaturated groups per molecule and (B) a compound having at least two mercapto groups per molecule. present in the composition.

Examples of compounds having at least two reactive unsaturated groups per molecule used in the present invention include at least two vinyl groups, acryloyl groups, methacryloyl groups, allyl groups, and arylidene groups per molecule. Examples include compounds having groups, and specific examples thereof include the following compounds.

(a) Vinyl compounds divinylbenzene, divinyl adihate (b) Acryloyl compounds ethylene glycol diacrylate, trimethylol pronoglycrylate, pentaerythritol tetraacrylate, bisphenol A epoxy noacrylate (c) Methacryloyl compounds ethylene glycol diacrylate, trimethylol Propane trimethacrylate, pentaerythritol tetramethacrylate, bisphenol A epoxy dimethacrylate) Allyl compounds diallyl phthalate, diallyl succinate, diallyl anovate, triallyl isocyanurate, nobricol bisallyl carbonate, triallyl cyanurate,
Noallyl maleate, diallyl fumarate (e)allylidene compound Diallylidenepentaerythritol, triarylidene rubitol, diallyligantetramethylol cyclohexanone These compounds (5) may be used alone or in a mixture of two or more. You may also use it. In addition to those exemplified above, compounds having at least two unsaturated cycloacetal groups in one molecule represented by the following formula can also be used as the above-mentioned (e) IJ compound.

and/or) Specific examples of compounds having at least two unsaturated cycloacetal groups in one molecule include the following.

(a) diarylidenepentaerythritol and (
or) diarylidene-tetramethylolcyclohexanone and (b) ethylene glycol, diethylene glycol, triethylene glycol, propylene gellicol, dipropylene glycotyl, 1,3-butanediol, 1,
6-hexanediol, polyethylene glycol, hydrogenated bisphenol A1 bisphenol/l/A-ethylene oxide adduct, hisphenol A-propylene oxide adduct, trimethylolethane, trimethylolethane, pentaerythritol, dipentaerythritol, Ethylene oxide or propylene oxide adducts of phthalic acid, isophthalic acid and/or terephthalic acid, polyols such as polyesters containing terminal hydroxyl groups with a molecular weight of 1500 or less, or (C) notothioglycol, nobentenedimerkabutane, ethylcyclohexylnomer Polythiols such as kabtan, 1,6-hexane dimercaptan, thioglycolic acid, β-
Compounds containing a total of two or more hydroxyl groups and ('' or) mercapto groups per molecule, such as esterified products obtained by reacting mercaptopropionic acid or mercaptosuccinic acid with the above polyols, or (d) phenol, cresol, and these. Phenols such as novolak, bisphenol F1 and bisphenol A obtained by formalin condensation, or (e) arylsulfonamides such as benzenesulfonamide, 0-toluenesulfonamide, p-toluenesulfonamide, and ralbenzenesulfonamide; f) Reaction product (It) having two or more reactive unsaturated groups at the terminal with the above (,) to (,) mixtures thereof Monoallylidene trimethylol pronogne and/or monoallylidene trimethyl Two or more reactive unsaturated groups are added to the terminals of methylolethane and incyanate compounds such as tolylene diisocyanate, ?realkylene allyl isocyanate, metaphenylene noisocyanate, xylylene diincyanate, hexamethylene diisocyanate, and inphoron diincyanate. The reaction product with (
III) monoarylidene trimethylolpronogne and ('i
or) monoallylidene trimethylolethane and succinic anhydride, maleic anhydride, itacone anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, head acid anhydride, etc. Addition half-esterified product having two or more reactive unsaturated groups at the terminal with carboxylic acid anhydride ([V) Heptanoarylidene trimethylolpronogne and/or monoaryligan tririchloethane and carboxylic acid anhydride Reactions with two or more terminals obtained by reacting an addition half-ester with a compound with an epoxy compound such as a polyvalent glycidyl ether type epoxy compound or a diglycidyl ester type epoxy compound such as phthalic acid, anovic acid, or dimer acid. Compounds with sexually unsaturated groups.

Φ) used in the present invention, at least two per molecule,
Examples of compounds having a mercapto group (H8-) include:
Aliphatic or aromatic mercaptans include nobentenedimercaptan, ethylcyclohexylsomerbutane, 1,6-hexadimercaptan, and mercapto compounds having carboxyl groups and polyhydric alcohols. Ester compounds of thioglycolic acid or β-mercaptopropionic acid, esters of mercaptosuccinic acid and polyhydric alcohols, such as esters of trimethylolpronogne and trimethylolethane, pentaerythritol and dipentaerythritol esterified product, β- to the mercapto group
Compounds having a hydroxyl group on a carbon atom, compounds obtained by the reaction of an epoxy resin with hydrogen sulfide, compounds obtained by the reaction of an epoxy resin with thioglycolic acid, etc., and one or more of these are used. can.

The blending ratio of compound (A) and compound (B) is not particularly limited, but if the blending amount of compound (A) is large, it will take a long time to cure, and - the blending ratio of deterioration compound (B) may be If the amount is too large, the reaction will not be completed and the molecular weight of the product will be low.
-1 to 10/1, preferably 1 to 5/1.

The composition of the present invention is prepared by blending compound (g) and compound (B), or adding other additives such as a polymerization initiator,
It can be cured by heating and/or irradiation with high-energy radiation such as ultraviolet light, X-rays, gamma rays, and electron beams.

As the polymerization initiator, for example, a radical polymerization initiator such as a peroxide such as benzoyl peroxide or an azo compound such as azobisisobutyronitrile nato can be used. For ultraviolet curing, various known photopolymerization initiators such as benzoisoalkyether can be used.

If desired, two or more of the above-mentioned reactive monomers or oligomers may be mixed and used in the composition of the present invention within a range that does not impair the essence of the composition. In some cases, it is also possible to use a monofunctional monomer such as methyl methacrylate. For example, when a compound having an unsaturated cycloacetal group and a compound having a mercapto group are combined and cured, a hexamer or oligomer that can be copolymerized with these and can be uniformly mixed;
Aliphatic polyfunctional acrylates such as ethylene glycol diacrylate, ethylene glycol dimethacrylate, trimethylolpropane triacrylate, hentaerythritol tetraacrylate; diglycol bisallyl carbonate, diallyl phthalate, triallyl cyanurate, triallyl in cyanurate, diallyl Allyl compounds such as maleate and diallyl fumarate, reactive polymers such as methyl methacrylate, and reactive oligomers such as epoxy acrylate can be used in combination.

In addition, the composition of the present invention may optionally contain a surfactant,
Leveling agents such as silicone resins, polymerization regulators, deterioration inhibitors, ultraviolet absorbers, antistatic agents and other additives can be added.

Although there are no particular restrictions on the method of manufacturing the information recording disc according to the present invention,
In order to manufacture information recording disks such as disk substrates based on the present invention, it is convenient to use the casting method.

For example, an information recording part with uneven shapes such as information bits (protrusions) or tracking grooves is formed on a glass or metal plate using a method such as a photoresist method, and based on this information, a reproduction mold for molding (such as polyester) is formed. stamper)
A thin metal film is coated on the surface of the stamper, and the composition of the present invention, which is a liquid when heated at room temperature or under a specific temperature condition, for example, 100°C or less, is poured into the mold, and the composition is sufficiently heated. After spreading it to every corner of the mold, it is cured by heating and/or irradiation with high-energy rays, and after curing, it is removed from the mold to produce a disk substrate. At that time, when the mold is removed after curing, fine irregularities from the mold are found on the surface of the substrate. Alternatively, a substrate can be produced by injecting the composition between two glass plates having uneven parts, irradiating the composition with high-energy rays with the glass plates flattened, and removing the composition after curing.

Example Next, the present invention will be explained based on examples.

A polymerizable composition having the following formulation was prepared, coated on polyester Stan iE with a thin metal film applied to the surface, and pressed with a rubber roll sufficiently to spread the composition to every detail.

Table 1 shows the blending ratio of the polymer composition and the curing conditions.

The amounts of compounds (g) and Φ) used were each shown in equivalent units.

Thickness 1.2 mm and diameter 1 obtained in Examples 1 to 5 above
The results of comparing the 2tYn disk substrate with commercially available acrylic disk substrates and polycargonate disk substrates are as follows.
As shown in the table, the disk substrates of the examples of the present invention exhibited superior properties compared to the conventional acrylic disk substrates (Comparative Example 1) and polycarbonate disk substrates (Comparative Example 2).

Effects of the Invention The material of the present invention is transparent, has a high surface strength, is resistant to scratches, and has the advantage of being resistant to cracking.

The material of the present invention has heat resistance because its molecules are three-dimensionally cross-linked, and is also chemically stable and hardly changes due to the action of chemicals. The moisture absorption rate of the material is lower than that of polymethyl methacrylate, and the refractive index of the material hardly changes or the material warps due to moisture absorption.

Because the casting method is used for molding, large pressures are not applied during molding unlike injection molding, and therefore birefringence does not occur.
Another major feature of this material is that the methane gas has a long life.

In the above explanation, the invention made by the present inventor will be mainly used in the field of application which is the background of the invention, which is a disk having irregularities such as information pits on the surface and which performs recording and reproduction using light. ), but the present invention is not limited thereto, and can be applied to other information recording disks, for example, by using a playback needle with electrodes, and by changing the capacitance due to contact and movement of the electrode needles. It can also be applied to capacitance conversion type information recording discs that read information.

Claims (1)

[Claims] A curable composition for information recording discs comprising (A) a compound having at least two reactive unsaturated groups per molecule and (B) a compound having at least two mercapto groups per molecule as essential components. .