JPS5969446A - Cover glass for watch - Google Patents

Abstract

PURPOSE:To obtain cover glass for a wrist watch while providing the same appearance to many sheets of glass under certain set conditions in a finishing stage by forming a thin transparent colored film on the rear side of inorg. cover glass so as to change continuously the depth of the color. CONSTITUTION:The rear side of inorg. cover glass for a wrist watch is coated with an ultraviolet-curing acrylic resin and irradiated with ultraviolet rays to cure the resin. The glass is immersed in methanol contg. a colorant heated to 40-80 deg.C to color the surface of the acrylic resin by slight etching. The glass is slowly pulled up so that parts of the glass are immersed for different times. The depth of the color is continuously changed, and desired cover glass for a watch is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gradation-colored inorganic cover glass for a wristwatch.

Due to the diversification of wristwatch designs, colored glass is increasingly being used. The method of coloring the surface of inorganic glass allows small lots of glass to be easily colored in various tones, and it is also possible to change the color density within a single piece of glass. The aim is to obtain a cover glass whose density changes continuously by applying a thin transparent color to the back side of an inorganic cover glass.

To explain the present invention in detail, an ultraviolet curable acrylic resin is applied to the back surface of an inorganic cover glass, the resin is cured by irradiation with ultraviolet rays, heated, a coloring agent is added, and the glass is placed in methanol. By dipping, the surface of the acrylic resin can be slightly etched and colored. The longer the immersion time, the darker the color tone. Therefore, in the present invention, the glass is slowly pulled up after immersion, so that the immersion time is consistent within a single piece of glass, so that the color density changes continuously. It is something.

Considering the conventional method of continuously changing the color depth of inorganic glass, the method of applying paint directly to the glass tends to cause color unevenness, and the paint tends to accumulate especially at the edges, causing the color to become dark. In addition, there was a drawback that it was difficult to achieve a uniform finish when coloring a large number of glasses.However, the present invention eliminates this drawback and allows the appearance of glass whose density changes continuously. It is possible to achieve an extremely good finish, and by setting process conditions, a large number of glasses can be finished with the same appearance.

Traditionally, it has been possible to color acrylic cover glass so that the color density changes continuously by immersing it in methanol containing a colorant and gradually lifting it out. In the present invention, a similar coloring method can be applied to inorganic glass by forming an acrylic resin layer on the back surface of the inorganic glass.

This will be explained below with reference to Examples.

First, an ultraviolet curing type acrylic resin paint was dropped onto the back surface of a cover glass, and the resin was shaken off by rotating at a speed of 2000 rpm using a spinner to form a resin layer with a uniform thickness. Next, the resin was cured by irradiating ultraviolet rays for 1 minute from a distance of 4 ocrn with a water trowel lamp, and a transparent resin film with a thickness of about 2 μm was formed on the back surface of the cover glass. Next, 1.0 weight of a blue colorant was added to methanol and heated to 60°C.

The cover glass was immersed in this solution so that the top end of the glass would come out of the methanol after 2 seconds, and then pulled up at a constant speed, so that the bottom end of the glass would come out of the liquid after 10 seconds. After lifting the glass, it was thoroughly washed with water and dried.

The cover glass created by this process was lightly colored at one end, darkly colored at the other end, and the density was continuously reduced in between, making it unique in design. The quality of this glass was sufficiently satisfactory as a watch glass, such as abrasion resistance and water resistance.

In the present invention, the color concentration can be adjusted by changing the concentration of the colorant added, the temperature of the methanol immersed, and the immersion time, and the color density can be adjusted by changing the speed at which the glass is lifted out of the methanol. You can control how the color changes inside the glass. Furthermore, by changing the type of colorant, any color tone can be obtained.

As described in the Examples above, according to the present invention, an inorganic cover glass whose concentration changes continuously can be easily obtained.

[Brief explanation of the drawing]

The drawing is a cross-sectional view of a watch cover glass according to the present invention. 1. Cover glass 2°. Acrylic resin layer and above Applicant Daini Seikosha Co., Ltd. Agent Patent attorney Tsutomu Mogami

Claims (1)

[Claims] UV-curable acrylic resin is applied to the back side of the inorganic glass cover glass and irradiated with UV light.
n'l cure, add colorant, and heat from 40°C to 80°C.
A watch cover glass characterized in that it is colored so that the concentration changes continuously by immersing it in methanol heated to ℃ and gradually lifting it up.