JPS62174117A - Manufacture of optical disc board - Google Patents

Abstract

PURPOSE:To obtain a board which is excellent in releasability, in transparency and in adhesion to ultraviolet-curing resin, by a method wherein silicone containing alkoxy or hydroxyl group is used and a mold treated with releasant is used in combination. CONSTITUTION:A resin composition consisting of epoxy resin, acid anhydride, reaction accelerator an 3wt% and more of organic silicone containing alkoxy group or hydroxyl group is poured in a casting mold on which MgF2 and CaF2 are used as external releasants, so as to be cured. In other words, the resin composition consisting of epoxy resin, acid anhydride, reaction accelerator and organic silicone is poured in a casting mold consisting of two opposing glasses which are spattered with MgF2 and CaF2 in combination, a releasability, which is several times excellent than the releasabilities each of which is expected when singly used, is shown.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method of manufacturing a plastic optical disk substrate. More specifically, when manufacturing optical disc substrates using edoxy resin, it has excellent patternability with the mold in cast molding, can be easily removed from the mold, and forms groups on the substrate. The present invention relates to a method for manufacturing an optical disk substrate that has excellent adhesion to an ultraviolet curable resin for the purpose of making the substrate more durable.

[Prior art]

Plastic optical disk substrates are made of thermoplastic resins such as iricarbonate and polymethyl methacrylate;
Those made of thermosetting resins such as golidiallyl diglycol carbonate are known. Among these, optical disk substrates made of cured edoxy resins are the most reliable as high-quality disk substrates in terms of heat resistance, birefringence, low water absorption, etc. (Japanese Patent Application Laid-Open No. 59-22248). The general method for manufacturing such an optical disk substrate is to pour nixy resin into a cavity between two glass sheets facing each other through a glass, heat and harden the resin, and then demold the resin to obtain a disk substrate. In order to impart mold releasability to the glass used here, for example,
MgF2.-153608. There is a method of forming a thin film using a metal fluorine compound such as , CaF2, etc. by a snow trickling method. However, when using resin systems such as bisphenol A epoxy resins that inherently have excellent adhesion to glass, it is difficult to remove the mold after curing, even with mold-release-treated cavities, which often results in damage to the glass or substrate. Met. One way to solve this problem is to add an internal mold release agent; an example of this is the use of organic silicone in an epoxy resin-phenol novolac curing agent system as shown in JP-A-60-18520. However, this is limited to the epixy resin-7enol novolak curing agent, and it is stated that the epixy resin-acid anhydride system has the disadvantage of whitening under high temperature and high humidity conditions. It is also conventionally known to add silicone resin as a substitute for organic silicone. In any of these cases, the mold release agent floats on the surface of the cured product, causing a so-called bleed phenomenon, so there is a mold release effect, but due to the presence of a large amount of silicone on the surface, so-called 2P (photo-polymer) ) method has the disadvantage of very poor adhesion to the ultraviolet curable resin used in the step of forming groups.

[Purpose of the invention]

The present invention was developed as a result of studies aimed at solving the problems associated with such manufacturing methods.It was found that when an epoxy resin for optical disk substrates - an organic silicone compound containing an acid alkoxy group or a hydroxyl group is added as an internal mold release agent, mold release properties and transparency are improved. It was discovered that a cured product with good adhesion to the Ka2P resin could be obtained, and this was completed.

[Structure of the invention]

The present invention consists of an epoxy resin, an acid anhydride, and a reaction accelerator.
The present invention relates to an optical disc substrate obtained by curing a resin composition made of the organic silicone containing an alkoxy or hydroxyl group.

[Purpose of the invention]

The present invention was developed as a result of various researches to solve the problems related to the manufacturing method of optical disk substrates based on the epixyl resin-acid anhydride system. This led to the discovery that the resulting cured product has excellent mold releasability, good transparency, and excellent adhesion to the ultraviolet curable resin.

[Structure of the invention]

The present invention uses a resin composition consisting of an epoxy resin, an acid anhydride, a reaction accelerator, and an organic silicone containing 3% by weight or more of alkoxy or hydroxyl groups as an external abrasive, and uses MgF2,
The present invention relates to a method of manufacturing an optical disc substrate by casting it into a casting mold using CaF2 and curing it.

In the present invention, organic silicones containing hydroxyl groups and alkoxy groups are particularly effective in the epixy resin-acid anhydride system, whereas organic silicones containing other groups cannot be expected to have such effects.

To explain the contents of the present invention in detail, by adding reactive silicone as an internal template agent, a condensation reaction is caused with hydroxyl groups in the composition, and the silicone is injected into the matrix of the cured product. As a result, the silicone does not bleed onto the surface and the cured product does not become cloudy due to its good compatibility. Furthermore, since the concentration of silicone present on the surface is lower than when non-reactive silicone is added, a cured product with excellent mold releasability during substrate production can be obtained without impairing the adhesion with the ultraviolet curable resin.

It is also worth mentioning that by adding silicone resin, light resistance, water resistance, etc. can be further imparted, so that a disk substrate with higher reliability can be obtained. The epoxy resin, acid anhydride, and reaction accelerator used in the present invention have already been exemplified in JP-A-59-22248, etc., but regarding the epixy resin in this case, so-called bisphenol A-type edoxy resin, bisphenol F-type edoxy resin, etc. This effect can be achieved with resin systems that have excellent adhesion to glass, such as resins, but alicyclic epixy resins and the like can also be added as necessary. It is possible to add reactive silicones to certain known materials.

The organic silicone has an alkoxy group and a hydroxyl group, and any organic silicone can be used as long as it has good compatibility with the resin, but it should be added in an amount of at least 3% by weight or more in order to exhibit a mold release effect.

Further, the method for manufacturing a disk substrate according to the present invention is as follows. Epoxy resin, acid anhydride,
A resin composition consisting of a reaction accelerator and an organic silicone is cast and then heated and cured to form a mold to obtain a disk substrate.

It is surprising that when these resin compositions are used in combination with the above-mentioned MgF2 and CaF2 treated casting molds, they exhibit mold releasability that is several times better than that expected when each resin composition is used alone. It is.

Example 1 A glass plate on which a thin film of MgF2 was formed by the Sufu ζ ivy method was
The first two sheets were placed facing each other, and the first
An epoxy resin composition having the formulation of Example 1 shown in the table was cast and cured and demolded at 100°C for 3 hours and at 120°C for 2 hours. For mold releasability, if the mold can be easily removed by inserting a knife or the like into the interface of the cured glass and creating a trigger and blowing air, the mold releasability is evaluated as good, and in other cases, the mold releasability is difficult.

Other properties are shown in Table 1.

Example 2 Curing was performed using the formulation shown in Table 1 in the same manner as in Example 1,
I removed the mold. The results are shown in Table 1.

Comparative Example 1 The formulation shown in Table 1 was cured, and the mold was demolded in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 2 Phenylmethylterisiloxane was added as the silicone shown in Table 1, and cured and demolded in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 3 Casting was carried out under the same conditions using a glass plate on which a thin MgF2 film was not formed using the recipe shown in Example 1, but it was extremely difficult to remove the mold after curing, and the glass plate It's damaged.

Claims (1)

[Claims] MgF_2, CaF_
1. A method for manufacturing an optical disk substrate, which is obtained by casting the substrate into a casting mold treated in step 2, curing it, and then releasing the mold.