JPH0232681B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to disc records such as audio discs and video discs, and in particular has a surface structure that is faithful to the signal engraved on the surface of the master disc when these disc records are manufactured from the master disc, and has a surface structure that is faithful to the signal engraved on the surface of the master disc when manufacturing these disc records from the master disc. When a signal is reproduced by a mechanical method, it is an object of the present invention to provide a disc record in which the signals engraved in the grooves of the disc record are not worn away by the record stylus. In the field of the record industry, to obtain audio discs, for example, original master discs (stampers) with signals engraved in grooves on the metal surface are used, and a copolymer of vinyl chloride and vinyl acetate is compression molded. Producing disc records.
However, in discs with high-density signals, such as video discs, the structure in which the recorded signals are engraved is very fine, so there is a problem that good reproduction signals cannot be obtained due to the inaccuracy of molding. There is. Therefore, there is a need for a technique for manufacturing a disc record having a signal that is faithful to the signal engraved on the stamper. Furthermore, when reproducing signals using a diamond stylus or the like, there is a strong desire for a disc record with good wear resistance so that the signals engraved on the disc will not be worn out or deformed. On the other hand, from a production standpoint, it is necessary that the disc record be easily peeled off from the stamper after manufacturing, that is, it must not have adhesion to the stamper. The present invention satisfies these demands and is a method for manufacturing a disc record, for example, by coating a part or the entire surface of a stamper on which a signal is engraved with a liquid resin that can be cured by irradiation with ultraviolet rays. Then, a support made of a transparent plate is pressed onto the support so that the liquid resin has a uniform thickness. Next, the liquid resin is cured by irradiating ultraviolet rays through the support, and then the support is peeled off from the stamper together with the cured resin adhering to it, thereby obtaining a disc record. If the same operations as described above are carried out simultaneously or separately on the other surfaces of the support, a disc record having a resin film with signals engraved on both sides of the support can be obtained. As a liquid resin that can be cured by irradiation with ultraviolet rays, an ultraviolet curable resin containing only 2,2-bis(4-acryloyloxypolyethyleneoxyphenyl)propane represented by the following structural formula () is used as an ultraviolet curable resin component. It contains a mold resin and 2 to 4% by weight, preferably 3% by weight of a photopolymerization initiator. (However, m and n are integers, and the sum of m and n is 3~
4). By using this, a disc record was produced which had excellent removability from the stamper and fidelity of signal transfer engraved on the stamper surface, and also had extremely good abrasion resistance due to diamond needles. The reason for this is that the shrinkage rate of the ultraviolet curable resin of the present invention is as low as 5.8%, and the Vickers hardness is also as low as about 10, for example. Note that when the amount of photopolymerization initiator added is less than 2% by weight, the time required for photocuring increases,
Disk record productivity decreases. On the other hand, if the amount added is too large, the properties of the cured film, especially the mechanical properties, will deteriorate. Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of the disc record, and FIG. 2 is an enlarged cross-sectional view taken along line X-X'. The disc record is an ultraviolet-transparent plate support made of at least a copolymer of vinyl chloride and vinyl acetate, polymethacrylate resin, polystyrene resin, polycarbonate resin, cellulose resin, or any of the above resins with an adhesive layer provided on the surface. 1 and an ultraviolet curing resin film 2, the surface of the film 2 is provided with grooves 3 in which signals are carved. The ultraviolet curable resin film consists of an ultraviolet curable resin consisting of 97% by weight of 2,2-bis(4-acryloyloxydiethyleneoxyphenyl)propane and 3% by weight of benzoin isopropyl ether. Ultraviolet curing resin (UV resin) of this example
The average molecular weight of this material is approximately 510, and although it has a low molecular weight, its viscosity coefficient is approximately 2000 cp, so even when pressed against a substrate, air bubbles are unlikely to form, making it possible to obtain disc records of stable quality. Here, the relationship between molecular weight and viscosity will be explained. For polymers of the same type (for example, acrylic resins with different molecular weights), there is a relationship between molecular weight and viscosity (viscosity of a solution of a certain amount dissolved in a certain solvent). That is, a method has been established for determining the molecular weight of a polymer (in this case, called viscosity average molecular weight) by measuring the solution viscosity. However, the reality is that no regulatory relationships have been recognized between ordinary low-molecular-weight molecules or between different types of molecules. For example, trimethylolpropane triacrylate (molecular weight 296) is approximately 70 cp at 25°C, whereas pentaerythritol triacrylate (molecular weight 298)
shows approximately 770 cp at 25°C. In this way, with regard to the viscosity between different molecules, especially in low-molecular systems, the stronger the interactions between molecules (for example, hydrogen bonds between molecules, Coulombic forces between polar groups, etc.), the less fluidity becomes, and the viscosity decreases. It gets expensive. Further, as the shape of the molecules becomes longer, even if the molecular weight is the same, entanglement between molecules occurs, which is accompanied by an increase in viscosity. Furthermore, it is related to the freezing point, and it is thought that near the freezing point, due to some crystallization, the interaction between molecules becomes stronger and the viscosity increases. As mentioned above, the viscosity of a substance made of low-molecular-weight molecules is, of course, slightly affected by the molecular weight of each individual molecule, but it is also affected by the characteristics of the aggregate of the molecules, such as the It is greatly influenced by interactions, entanglement of molecules due to their shape, etc. In addition, the UV resin of this example has a primary skin irritation index of 0.8, which is even compared to the index of other resins (e.g., butanediol diacrylate: 8.0, trimethylolpropane triacrylate: 4.6).
The resin of this example has a smaller value and is superior in terms of safety and hygiene and handling. Furthermore, this coating 2 has good releasability from the stamper, and is particularly excellent in abrasion resistance against diamond needles in the grooves 3 in which the signals are engraved. The table below shows the cured film of the UV-curable resin of this example and the cured film of a material partially diluted with low-molecular-weight UV resin, for example, as Comparative Example 1, 20 wt% was replaced with neopentyl glycol diacrylate. The cured film of the cured material, and as Comparative Example 2, trimethylolpropane triacrylate

[Table] Note that a certain degree of softness is required to withstand abrasion caused by needles, and UV resins require polyfunctional low-molecular
If it is hardened by replacing it with UV resin, it will become brittle and more likely to be scratched by needles. Further, it is said that a hardness of 11 or less is desirable. In addition, in order to modify the properties of the film 2, various additives can be added to the liquid resin that is cured by ultraviolet rays. For example, dyes for coloring, defoaming properties of liquid resin, defoaming agents to improve wetting with stampers, surfactants such as wetting agents,
Alternatively, there are thermosetting catalysts such as organic peroxides that effectively utilize the heat generated from the lamp during ultraviolet irradiation.

[Brief explanation of drawings]

FIG. 1 is a partial plan view showing an embodiment of a disc record according to the present invention, and FIG. 2 is a sectional view taken along the line X-X'. 1... Plate support, 2... Ultraviolet curing resin film, 3... Groove.

Claims (1)

[Scope of Claims] 1. A disc record in which a transparent plate is used as a support and an ultraviolet curable resin film having unevenness representing information on the surface is applied to one or both sides, wherein the resin film is an ultraviolet curable resin film. As a resin component, a resin composition containing only 2,2-bis(4-acryloyloxypolyethyleneoxyphenyl)propane represented by the following structural formula () and 2 to 4% by weight of a photopolymerization initiator A disc record characterized by being obtained by curing a material. (However, m and n are integers, and the sum of m and n is 3~
4) 2 The transparent plate is made of at least a copolymer of vinyl chloride and vinyl acetate, a polymethacrylate resin, a polystyrene resin, a polycarbonate resin,
The disc record according to claim 1, characterized in that it is made of a cellulose resin or the above-mentioned resin with an adhesive layer provided on its surface.