JPH0816991B2 - Optical disc and its manufacturing method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an optical disc and a method for producing the same, more specifically, an optical disc obtained by laminating a pair of substrates using a specific UV-crosslinkable hotmelt adhesive and a method therefor. Regarding manufacturing method.

2. Description of the Related Art Problems to be Solved by the Prior Art and Invention An optical disc formed by laminating a pair of substrates is provided with an optically readable information recording section on at least one of the substrates, and a video disc or a digital audio disc,
It is used as a disk for files of documents and data.

Incidentally, in the production of optical discs, epoxy-based adhesives, urethane-based adhesives, UV-curable adhesives, hot-melt adhesives, etc. are usually used for the above-mentioned bonding. However, epoxy-based adhesives and urethane-based adhesives have a slow curing speed and have a problem in productivity, and in the ultraviolet-curable adhesive, the monomer components contained therein may erode the substrate. Further, the hot melt adhesive has a problem of low heat resistance.

An object of the present invention is to solve the above problems, and to provide a highly reliable optical disk having high productivity, no erosion, and high heat resistance, and a method for manufacturing the same.

The inventors of the present invention have conducted extensive studies to achieve such an object, and if one of the substrates is coated with an ultraviolet-crosslinkable hotmelt adhesive, and ultraviolet irradiation (UV irradiation) is performed,
The physical properties of the hot melt adhesive (HMA) component can be changed to a high softening point and high viscosity to increase heat resistance, and there is no fear of erosion, and optical disks can be manufactured with high production efficiency. The present invention has been completed and the present invention has been completed.

Structures and effects of the invention That is, the present invention is an optical disk, which is formed by laminating a pair of substrates, and an information recording portion is provided on at least one of the substrates, and the ultraviolet-crosslinkable HMA is used for the laminating. The optical disc, and a pair of substrates provided with an information recording unit on at least one of them is coated with UV crosslinking HMA on one substrate, and after irradiating with UV, the other substrate is bonded to the coated surface. The present invention provides a method of manufacturing an optical disc.

The UV-crosslinkable HMA used in the present invention requires, for example, an HMA base component, a saturated hydrocarbon resin oligomer containing at least one acryloyl group in one molecule as a UV-crosslinkable component, and a photopolymerization initiator, Furthermore, it is composed of a system to which usual fillers, anti-aging agents, polymerization inhibitors, etc. are added as necessary, and in the composition, erosion of the substrate is caused, and thickening and gelation by thermal polymerization are caused. It does not contain any radically polymerizable monomers that cause it.

The above HMA base component has adhesiveness at room temperature and has the formula: AB, ABAA or BAAB [wherein A is a polystyrene block having a molecular weight of 2000 to 12500, And B is a polybutadiene block, a polyisoprene block or an ethylene butylene copolymer block having a molecular weight of 1000 to 250,000], one or more of the block state plastic elastomers, or a synthetic rubber (polyisoprene,
Styrene rubber, butadiene rubber, butyl rubber, etc.), polyolefin or polyolefin copolymers (polyethylene, polypropylene, ethylene-vinyl acetate copolymer, etc.), and tackifiers (rosin resin, hydrogenated petroleum resin, hydrogenated terpene resin, It is preferable to add an appropriate amount of a phenol resin, a coumarone resin, etc.) and a softening agent (process oil, paraffin oil, polybutene, polyisobutylene, etc.). Hydrogenated tackifiers have good compatibility,
It does not adversely affect the thermal stability, and has a low water absorption rate, thus providing good corrosion resistance.

At least 1 in one molecule that is the above-mentioned UV-crosslinkable component
The saturated hydrocarbon resin oligomer containing one acroyl group is specifically a saturated hydrocarbon resin oligomer containing at least one hydroxyl group or carboxyl group in one molecule (hydrogenated polybutadiene, polybutene, hydrogenated Acrylate, urethane acrylate, epoxy acrylate or ester acrylate of polyisoprene, polyisobutylene, etc.) is referred to, and one or more of these are used. The amount used is usually 5 to 100 parts, preferably 10 to 40 parts, relative to 100 parts of HMA base component (parts by weight; the same applies hereinafter). If it is less than 5 parts, the effect of improving heat resistance by ultraviolet irradiation is low, and
If it exceeds 100 parts, the tackiness tends to decrease.

Examples of the photopolymerization initiator include usual benzoin ether type (benzoin isopropyl ether, benzoin butyl ether, etc.) and benzophenone type (benzophenone, p
-Methoxybenzophenone, p-bromobenzophenone, etc.), acetophenone type (benzyl methyl ketal,
2,2-diethoxyacetophenone, 1,1-dichloroacetophenone and the like), and thioxanthone type (2-chlorothioxanthone and the like). The amount used is usually 0.5 to 5% by weight based on the total amount of the HMA base component and the UV-crosslinkable component.

The method for producing an optical disk according to the present invention is characterized by using the above UV-crosslinkable HMA (melt viscosity is generally set to 5000 to 500000 cps at 120 ° C.) and irradiating it with UV. It will be explained based on.

In FIG. 1, an acrylic plate, a polycarbonate plate,
A disk base material (1 to 3) in which an optically readable information recording section 2 is provided on a substrate 1 such as an amorphous polyolefin plate or a glass plate, and a protective film 3 is further formed thereon as necessary. , Usually UV-crosslinkable HMA4 melted at a temperature of 80-160 ℃ is applied in a thickness of 10-50μm, then 2
After UV irradiation for 20 seconds, the disk substrates (1 'to 3') are superposed and compressed at 0.2 to 20 Kg / cm ² according to the irradiation, whereby the illustrated optical disk of the present invention is obtained. In the optical disc of the present invention, one or both of the information recording portion (2, 2 ') and the protective film (3, 3') may be omitted, as in the conventional optical disc.

Next, the present invention will be described more specifically with reference to Examples and Comparative Examples.

Example 1 (1) Preparation of UV-crosslinkable HMA Component Polystyrene-ethylene butylene copolymer Block-like thermoplastic elastomer [Califlex GX-1726 manufactured by Shell Chemical Co., Ltd.] ...... 20 parts Acryloyl group at both ends (urethane acrylate type) ) Containing hydrogenated polybutadiene oligomer [TEAI-3000 manufactured by Nippon Soda Co., Ltd.] ...... 25 parts Hydrogenated styrene-based tackifier [Rika Hercules Co., Ltd.]
Made by Rigalets 1094] ...... 40 parts Polyisobutylene [Nippon Oil Co., Ltd., Tetrax
3T] ...... 10 parts benzyl methyl ketal [Nippon Ciba Geigy Co., Ltd.]
Manufactured by Irgakiure 651] ... 3 parts The above components are mixed together to obtain an UV-crosslinkable HMA (melt viscosity at 120 ° C: 70,000 cps).

(2) Manufacture of optical disk Aluminum is vapor-deposited on a 30 cm diameter injection acrylic substrate having a pit recording information area, and one of a pair of disks coated with an ethylene-vinyl acetate copolymer protective film is coated with a hot melt roll. Using a coater, the UV-crosslinkable HMA of (1) above is applied at a temperature of 120 ° C. to a thickness of 30 μ. Next, 0.9 W · S / cm ² of ultraviolet light was irradiated from a distance of 10 cm by a high pressure mercury lamp (80 W / cm), and then the disks were bonded together at a pressure of 10 Kg / cm ² to complete an optical disk.

Comparative Example 1 In Example 1, SIS rubber [Califlex TR-11 manufactured by Ciel Chemical Co., Ltd.
07] …… 30 parts Tackifier (Yasuhara Yushi Kogyo Co., Ltd., Clearon P105)…
50 parts oil [Ciel Frex 371 manufactured by Ciel Chemical Co., Ltd.
N] ...... 20 parts Anti-aging agent (Irganox, manufactured by Nippon Ciba Geigy)
1010) …… Using an ordinary HMA consisting of 2 parts, after coating with a hot melt roll coater, they were immediately laminated to complete an optical disc.

Comparative Example 2 In Example 1, a two-component room temperature curing type epoxy adhesive was used, and after application, it was laminated at a pressure of ² Kg / cm ² , and allowed to stand at room temperature for 24 hours until the adhesive was cured, and an optical disc was applied. completed.

Table 1 shows the performance evaluation results of the optical disks obtained in the above-mentioned Examples 1 and Comparative Examples 1 and 2.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of the optical disc of the present invention, in which 1,1 ': substrate, 2,2': recorded information part, 3,3 ': protective film, 4:
adhesive.

Claims (3)

[Claims] 1. An optical disk comprising a pair of substrates bonded together, and an information recording section provided on at least one of both substrates,
An optical disk characterized in that an ultraviolet-crosslinkable hot melt adhesive is used for the above-mentioned bonding. 2. An ultraviolet-crosslinkable hotmelt adhesive is a hotmelt-type adhesive base component, a saturated hydrocarbon resin oligomer containing at least one acryloyl group in one molecule as an ultraviolet-crosslinkable component, and photopolymerization initiation. The optical disk according to claim 1, which comprises an agent. 3. A pair of substrates, at least one of which is provided with an information recording portion, is coated with an ultraviolet-crosslinkable hot melt adhesive on one substrate, and is irradiated with ultraviolet rays, and then the other substrate is attached to the coated surface. Characteristic optical disk manufacturing method.