JP2982085B2 - Optical disc manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an optical disk for writing and reading information using laser light.

[0002]

2. Description of the Related Art In an optical disk of the present invention, since a groove and a pit pattern of a stamper are formed on a glass substrate using an ultraviolet curing resin, a surface treatment with a silane coupling agent is required on the glass substrate. . If the silane treatment is not performed, the ultraviolet curable resin may be peeled off from the glass substrate during the 2P molding, and even if the 2P molding is performed, there is a possibility that the resin will be peeled off over time. Conventionally, vinyltris (β-methoxyethoxy) silane has been used as the silane coupling agent, but methylcellosolve is generated by hydrolysis. This methyl cellosolve is highly toxic, so it was recently revised laws and regulations related to the Industrial Safety and Health Law (1
(Enforced on April 1, 990), the control concentration became strict, and work environment management became difficult. Some manufacturers are stopping production. Also, silicone primers such as AP113 and APZ66 manufactured by Nippon Unicar Co., Ltd.
05, APZ6607, ME12 manufactured by Toshiba Silicone Co., Ltd.
No. 3 have been proposed, but all of them have problems such as poor film formability, adhesion to resin, and poor transparency, and have not been practical.

[0003]

The object of the present invention is to provide a glass substrate which does not generate toxic substances, has good film-forming properties, and has good adhesion between the glass substrate and the ultraviolet curable resin. We propose a new method for manufacturing optical disks.

[0004]

SUMMARY OF THE INVENTION The present invention comprises an isopropyl alcohol / water mixture having an isopropyl alcohol / water ratio of 75/25 to 97/3 by weight, an acid and 2 to 5% by weight of vinylethoxysilane. A vinyl triethoxysilane is hydrolyzed in a mixed solution having a pH of 5.0 or less to prepare an oligomerized surface treatment solution, and the surface treatment solution is coated on a glass substrate and dried to form a thin film layer of the oligomer. And then laminating an ultraviolet curable resin layer on the thin film.

Hereinafter, the present invention will be described in detail. The glass substrate used in the present invention is not particularly limited as long as it is a glass such as tempered glass that can withstand the use of an optical disk.
As the silane coupling agent used in the present invention, vinyltriethoxysilane was selected on the premise that no harmful substances would be produced even when hydrolyzed, and that the adhesion to the ultraviolet-curable resin was good. The hydrolysis reaction formula of vinyltriethoxysilane is as follows.

CH ₂の CHSi (OCH ₂ CH ₃ ) ₃ + 3H ₂ O → CH ₂ ＣＨCHSi (OH) ₃ + 3CH ₃ CH ₂ OH In the hydrolysis of vinyltriethoxysilane, as a by-product, Toxicity poses almost no problem as ethanol is produced.

The ultraviolet curable resin used in the present invention is selected from unsaturated polyesters, polyfunctional acrylates, polyester acrylates, epoxy acrylates, urethane acrylates and the like.
Select one with good moldability. Particularly good ones include MP-107 and MP-121 manufactured by Mitsubishi Rayon Co., Ltd.

Next, the reaction mechanism between vinyltriethoxysilane and glass will be described. The reaction is a four-step process in which the three unstable ethoxy groups on silicon are hydrolyzed to form silanol groups. Next, the silanol groups are condensed to form oligomers. The oligomer forms a hydrogen bond with a hydroxyl group on the glass surface. Finally, water is released during drying to form a covalent bond with the glass, and a thin film layer of the oligomer is formed on the glass surface. In order to stably carry out the hydrolysis, the pH is adjusted using an acid such as acetic acid water. p
The pH before H adjustment was 5.3. At first glance, the glass surface seemed to be wet and the film-forming properties seemed to be good, but the hydrolysis did not proceed stably, so the oligomerization did not proceed, and the resin adhered. Poor. Adjust the pH to 5.0 with acetic acid water.
Hereinafter, for example, when it is set to 4.3, both the film forming property and the adhesion to the resin are improved. This is presumed to be because the solubility of vinyltriethoxysilane is improved and the hydrolysis proceeds stably by adjusting the pH. Although acetic acid water was used to adjust the pH, the acid is not particularly limited as long as the acid shows a weak acidity. For example, acids such as formic acid, benzoic acid and butyric acid can be applied to the present invention.

The amount of vinyltriethoxysilane added is 2 to
Good film formability can be obtained at 5% by weight. 2% by weight
If it is less than 10 mm, the outer peripheral portion of the glass becomes a frosted glass, and repelling occurs, which is not preferable. On the other hand, when the content is 5% by weight or more, fine clumps tend to occur. This is presumed to be because repelling occurs when the amount of the oligomer after hydrolysis is too small, and when the amount of the oligomer is too large, the oligomer becomes excessive and polymerizes, causing agglomeration.

The ratio of isopropyl alcohol / water is 75
/ 25 to 97/3, particularly 80/20 to 90/10, provides good film formability. When the amount of isopropyl alcohol is less than 75 parts, radial cissing is generated on the inner peripheral portion of the glass.
On the other hand, if the amount is 97 parts or more, clumping of the resin occurs, and the adhesiveness to the resin also deteriorates. In the former case, it is assumed that when the amount of isopropyl alcohol is reduced, the surface tension increases and the wettability with glass deteriorates, so that repelling occurs. Although the reason for the latter is unknown, it is also conceivable that isopropyl alcohol has some effect on the progress of hydrolysis (oligomerization, polymerization).

A method for preparing a surface treatment solution of vinyltriethoxysilane is to drop vinyltriethoxysilane little by little while stirring a mixed solution of isopropyl alcohol and aqueous acetic acid with a magnetic stirrer. The resulting liquid is left until hydrolysis and oligomerization proceed. 2 to leave
5 days. As a method of applying the surface treatment liquid to the glass substrate, a known thin film coating method such as a coating method using a spin coater can be employed. In the case of a spin coater, the coating amount (thickness) is determined by the amount of vinyltriethoxysilane added to the treatment liquid and the number of rotations. Usually, the thickness of the thin film layer is about 1 μm.

[0012]

【Example】

Example 1 First, a 10% by weight aqueous acetic acid solution is prepared. Next, a mixed solution of isopropyl alcohol and acetic acid water is prepared. The ratio of isopropyl alcohol / water in this case is about 91/9. Isopropyl alcohol 86.4 parts by weight 10% by weight acetic acid aqueous solution 9.6 While stirring this mixture with a magnetic stirrer, vinyl triethoxysilane (Silas Ace S manufactured by Chisso Corporation) was used.
220) 4 parts by weight (4% by weight) are added dropwise to obtain a surface treatment liquid having a pH of 4.5. This solution was added for 2 days (20 ° C, 65% R
H) Leave to stand. Next, surface treatment was performed on a tempered glass having a diameter of 130 mm (manufactured by Asahi Glass Co., Ltd.) with a spin coater (manufactured by Nikka Engineering Co., Ltd.) at a rotation speed of 800 rpm to form a good thin film layer without cissing on the glass surface.

Next, a nickel stamper (with grooves and pits) is set in a 2P molding machine, and a 2P molded product is applied to the surface-treated glass surface using an ultraviolet curing resin (MP-107 manufactured by Mitsubishi Rayon Co., Ltd.). Produced. The ultraviolet irradiation energy at this time was 1000 mJ / cm ² .
Both the adhesion between the resin and the glass during the 2P molding and the releasability between the stamper and the resin were good. Further, an adhesion test between the resin and the glass of the 2P molded product was performed. In the test method, a cellophane tape (manufactured by Nichiban Co., Ltd.) was attached to the resin surface, rubbed three times with a fingertip, and then peeled off by holding the end of the tape. As a result, no resin adhered to the tape and the adhesiveness was good.

Example 2 The ratio of isopropyl alcohol / water was set to 80/20 and p
A 2P molded product was produced in the same manner as in Example 1, except that the surface treatment liquid was H4.0. The film forming property of this 2P molded product and the adhesiveness to the resin were both good. Example 3 pH was adjusted to 2% by weight of vinyltriethoxysilane.
A 2P molded product was produced in the same manner as in Example 1 except that the surface treatment liquid of 4.5 was used. The film forming property of this 2P molded product and the adhesiveness to the resin were both good.

Comparative Example 1 A 2P molded product was produced in the same manner as in Example 1 except that the acetic acid water was replaced with water. This 2P molded product was unusable due to poor adhesion to the resin. This is probably because the solubility of vinyltriethoxysilane was poor and hydrolysis did not proceed. Comparative Example 2 A 2P molded product was produced in the same manner as in Example 1, except that the amount of vinyltriethoxysilane added was 1% by weight. This 2P molded product had poor film-forming properties, and repelling occurred, making it unusable. This is probably because the amount of oligomer was insufficient due to the small amount of vinyltriethoxysilane.

Comparative Example 3 A 2P molded product was produced in the same manner as in Example 1 except that the amount of vinyltriethoxysilane was changed to 6% by weight. This 2P molded product was unusable due to the formation of fine clumps. It is considered that the amount of the vinyltriethoxysilane was too large, and the amount of the oligomer was increased, so that it became easy to polymerize. Comparative Example 4 A 2P molded product was produced in the same manner as in Example 1 except that the ratio of isopropyl alcohol / water was 70/30. This 2P molded product was unusable due to radial cissing on the inner periphery. It is considered that because the amount of isopropyl alcohol was small, the surface tension was increased and the wettability with glass was deteriorated.

Comparative Example 5 A 2P molded product was produced in the same manner as in Example 1 except that the ratio of isopropyl alcohol / water was 98/2. The inner peripheral portion of this 2P molded product was ground glass-like and could not be used. Although the cause is unknown, it is considered that an excessive amount of isopropyl alcohol has some effect on hydrolysis, oligomerization and polymerization. Comparative Example 6 A 2P molded product was produced in the same manner as in Example 1 except that 3-aminopropyltriethoxysilane (Silaace S330 manufactured by Chisso Corporation) was used as a silane coupling agent. This 2P molded product was unusable due to poor adhesion to the resin. It is considered that the organic functional group of 3-aminopropyltriethoxysilane was an amino group, and was incompatible with the ultraviolet curable resin.

[0018]

According to the method of the present invention, it is possible to obtain an optical disk having good film-forming properties, good adhesion between the glass substrate and the ultraviolet-curable resin, and no peeling.

Claims (3)

(57) [Claims] An isopropyl alcohol / water mixture having a ratio of isopropyl alcohol / water of 75/25 to 97/3 by weight, a mixture containing an acid and 2 to 5% by weight of vinylethoxysilane and having a pH of 5.0 or less. A surface treatment solution is prepared by hydrolyzing vinyl triethoxysilane in a solution to form an oligomer, and the surface treatment solution is applied on a glass substrate and dried to form a thin film layer of the oligomer.
Next, an ultraviolet curable resin layer is laminated on the thin film. 2. The method for manufacturing an optical disk according to claim 1, wherein the surface treatment liquid contains an acetic acid aqueous solution. 3. The method for producing an optical disc according to claim 1, wherein the ratio of isopropyl alcohol / water in the surface treatment liquid is 80/20 to 90/10.