JPS63200341A - Optical information recording medium - Google Patents

Abstract

PURPOSE:To improve reliability of sealing by incorporating a specific compd. into an adhesive agent for concentrically adhering a pair of PC disks having an org. dye recording layer on the inside surface of at least one substrate to form a sealing construction by interposing inside and outside circumferential spacers therebetween or by other means. CONSTITUTION:The compd. expressed by the formula (R is H, methyl; n is 1-3) is incorporated into the adhesive agent 7 used for concentrically sticking a pair of the PC disk substrates 1, 1 having the org. dye recording layer 3 on the inside of at least one substrate 1 to form the sealing construction via the inside and outside circumferential spacers 7 or without interposing said spacers therebetween. The compd. expressed by the formula has the high adhesiveness to PC and has low volatility. The deformation of the PC disk substrates 1, 1 is decreased and the high adhesive strength is obtd. by sticking the substrates 1 by using the adhesive agent contg. such compd.; in addition, the good preservable property is obtd. The time for curing at the time of the sticking is reduced as well.

Description

[Detailed description of the invention] 〔Technical field〕 The present invention relates to a sealed optical information recording medium.

[Prior art]

The adhesive used to seal disc-shaped information recording media must (1) be free of reaction by-products during curing, and (2) be free of solvents so as not to affect the encapsulated recording material. It is required that it not be included. For this reason, epoxy adhesives are usually used. However, when using an epoxy adhesive, there are problems such as the plastic substrate being deformed by heating during curing and curing taking a long time. It has also been proposed to use it as a room-temperature curing epoxy adhesive, but the curing time is the same.

Therefore, in recent years, ultraviolet curing adhesives have been attracting attention. This is promising because it has the properties (1) and (2) above. However, when polycarbonate is used as a disk substrate, in order to obtain sufficient adhesion to the polycarbonate, it has hitherto been necessary to use a low-molecular-weight hexamer that can dissolve the polycarbonate to some extent. Since such monomers are generally highly volatile, if they are used, especially in so-called air sandwich type disks, the monomer components will volatilize inside the seal within a short time until the adhesive has completely cured, affecting the recording layer. It had the disadvantage of giving

〔the purpose〕

The present invention has been made in view of the above problems, and its purpose is to improve the sealing reliability of optical information recording media.

〔composition〕

As a result of various studies on soil adhesives for optical information recording media, the present inventor found that a compound of general formula (I) (wherein R represents hydrogen or a methyl group and n is IS3) was found to be suitable for polycarbonate. It was discovered that it has excellent adhesion and low volatility, and the present invention was completed.

That is, the above object of the present invention is to provide a disc-shaped substrate having an organic dye recording layer on one side of at least one of the two disc-shaped substrates.
The above general formula (I
) can be achieved by using an adhesive containing a compound.

In addition, for the purpose of further improving adhesive strength, general formula (I)
The compound has an acryloyl group (CI(2-CH) in one molecule.
An acrylate monomer having one acrylate monomer (COO-), a so-called monofunctional monomer, or a polyfunctional monomer having two or more acryloyl groups in one molecule may be used in combination. Examples of monofunctional monomers include, but are not limited to, the following.

CH2-CHCo(-OCH2CH2CH2CH2CH
2CO20H (n = 0 or 1-2) CH2 = CHCOOCH2CHOH ■ CH5 (n: 0 or 1-2) (m = 0 or 1-6, n = 0-12) CH2 = C
HCOO+CH2CHzO+-C2H5 (n=1 or 2) CHz=CHCO%0CH2CHz7=O turtle H2n+1
(m = 2 or more, n = 1 to 4) Also, a multifunctional product! Examples of - include, but are not limited to, the following:

CH2−CHCOOsoCH2jOCOCH<'H2(n
= 4~10)CH2=CHC00(-CH2cH
20+-COCH-CH2 (n = 3-15) (n
=4~10) (C)12-CI(COOCI(2-i c-cn2o
ouCH2髫疋COlow CH2C'H2CH2CH2CH
2C0O←(nsmxo, 1.2) When selecting the monofunctional monomer and the polyfunctional monomer, it is necessary to select those with low volatility.

The sealing adhesive in the present invention preferably has the general formula (I)
Compound of 40-70% by weight polyfunctional monomer 1
0-40% by weight Monofunctional 7mer 0-30% by weight
It can be prepared by mixing.

Next, the sealed optical information recording medium of the present invention will be explained based on the drawings.

The disk-shaped substrates 1, 1 are formed from injection molded plates of polycarbonate, for example, and have a fitting hole 2 in the center thereof, and on one side of these substrates 1, 1, for example, an organic dye recording layer 3 is formed. There is. These substrates 1, 1 are arranged via an inner circumferential spacer 4 and an outer circumferential spacer 5 concentrically disposed between the recording layers 5.3t and 1, and a space 6 is formed between mutually opposing surfaces of each recording layer 6.3. is formed using the sealing adhesive 7'f of the present invention.

Typical examples of the organic dye recording layer 30 include cyanine dye,
Examples include, but are not limited to, polymethine dyes such as merocyanine dyes. Furthermore, in place of the organic dye recording layer, a gold jI film recording layer such as ) can also be used. In addition to the illustrated configuration, the recording layer 3 may be formed on both sides of the substrate 1.1.

〔effect〕

The optical information recording medium of the present invention constructed as described above suffers less substrate deformation and has excellent storage stability compared to those bonded using conventional epoxy adhesives. Moreover, the curing time during lamination can be shortened.

〔Example〕

The present invention will be further explained below by way of examples as well as comparative examples, but is not limited thereto. In the examples, parts are expressed in parts by weight. In addition, in the general formula shown in the example, the acryloyl group CH2<HCO- is abbreviated as A.

Example 1 Two polycarbonate injection molded substrates with a diameter of 130 tml and a thickness of 1.2 mm were used, and a dye represented by the formula was placed on one of the substrates in a mixed solvent of methanol/1,2-dichloroethane (weight ratio 8:2). ) A recording layer was formed by spin-coding with a solution of 0.7% by weight dissolved in t-40Orpm, and then sealed using an adhesive having the following composition via a spacer having a thickness of [L5fi].

Bottom side 2CH20￥CH2CH2-A
20th part A-CH2CH2 Showa CXC? Part H1920 The adhesive of the present invention is of an ultraviolet curing type, and the light source is a high-pressure mercury lamp (
It was cured using a 2-pitch cure 2000 (manufactured by Ushio Inc.) at an illuminance of 50 mW/>" for an exposure time of 30 seconds.

Sealed discla 60"C, 9 produced as described above
The table below shows the results of measuring the disk characteristics after being left in an environment of 0% R and H for 1000 hours.

Examples 2 to 7 and Comparative Examples 1 to 2 Optical disks were fabricated in exactly the same manner as in Example 1, except that an adhesive having the composition shown below was used instead of the adhesive in Example 1. In addition, in each Example and each Comparative Example, 2,2-dimethoxy 2-phenylacetophenone was used as a photopolymerization initiator in the same manner as in Example 1. The results of measuring the characteristics of each optical disc are shown in the table below.

Example 2 A+CH2CH2O←CH2CH2-A
30 parts Example 3 CH3 A-CH2CH2CH2CH2CH2COOCH2-C
-COO-CH3 薯CH3 Example 4 Example 5 hgH2←A 20 parts Example 7 (AQH2CH20+ C(CH3) 2 65
20 parts Comparative example 2 A phrase H2CH2O+-CH2CH2-A
80 copies A-CH2m 20 copies ruled
Mi

[Brief explanation of the drawing]

The figure is a sectional view showing an example of the structure of an optical information recording medium according to the present invention. DESCRIPTION OF SYMBOLS 1... Substrate, 2... Fitting hole, 3... Recording layer, 4...
...Inner circumference spacer, 5...Outer circumference spacer, 6...Space, 7...Adhesive. Patent applicant Rico Co., Ltd. - 2 others

Claims (1)

[Claims] A pair of substrates having a recording layer on one side of at least one of two disc-shaped polycarbonate substrates, with or without an inner circumferential spacer and an outer circumferential spacer arranged concentrically. It has a sealing structure in which the recording layer is bonded with an adhesive so that it is on the inside, and the adhesive has a general formula ▲ mathematical formula, chemical formula, table, etc. ▼ (in the formula, R is hydrogen or a methyl group). and n is 1
-3).