JPS5922682A - Dial for clock - Google Patents

Abstract

PURPOSE:To prevent cracking, etc. of a coated surface by coating a transparent ultraviolet-ray curing resin on the surface of a dial, and irradiating ultraviolet rays while opening a shutter provided near the surface of the dial between the dial and an ultraviolet-ray lamp. CONSTITUTION:A transparent resin 1a is coated on the surface of a dial 1, and this dial is set under an ultraviolet-ray lamp at a distance of about 40cm. When a shutter 2 is opened at a speed of about 2mm./sec, the coated layer 1a is irradiated gradually from the right end, and cured gradually from the right end. The contraction of volume takes place with curing of the coated layer. However, as uncured resin at the end of cured part is drawn near, stress due to the contraction of the resin hardly occurs between the coated layer and the base plate of the dial.

Description

[Detailed description of the invention] The present invention relates to dial coating.

There are various surface finishes for watch dials, but most of them are transparent or have a rear finish. This is to improve the appearance of the dial and its quality such as corrosion resistance. For clear coating, resins such as acrylic are often used, but recently, ultraviolet curing resins are commonly used.

1- The reason is that compared to conventional resins, UV-curable resins have the advantage of having a longer pot life, being solvent-free, and curing with a short time of UV irradiation.

However, when an ultraviolet curable resin is used to clear coat the dial, there is a problem in that the printed layer tends to crack or peel off when the resin is applied to the entire surface of the dial and cured. This is because UV-curable resins shrink in volume when cured by UV irradiation, but as the curing occurs rapidly, stress is generated between the painted surface and the underlying dial board. .

The present invention aims to eliminate this drawback) and to obtain a printed dial plate of excellent quality that does not cause cracking or peeling of the painted surface even when the entire surface of the dial plate is coated with ultraviolet curable resin. It is something to do.

In other words, when UV rays are applied after coating the dial surface with an ultraviolet curable resin, the entire printed surface is not irradiated with UV rays at the same time, and a shutter is placed between the printed surface and the UV lamp near the printed surface. This method involves gradually opening the shutter and irradiating ultraviolet rays from one end of the painted surface to cure it. When the painted surface is cured using this method, the paint layer will shrink as it hardens, but when a part of the □ hardens and begins to shrink, the uncured part of the paint layer will be drawn to the hardened part. As the coating continues to harden, the stress generated between the paint layer and the dial substrate surface becomes extremely small. Therefore, cracking and peeling of the paint layer are less likely to occur.

The present invention will be explained in more detail below based on embodiments and with reference to the drawings. In the drawing, 1 is a dial plate, and the surface of the dial plate 1 is coated with transparent resin 1 (1″f), and this dial plate is set at a distance of about 40 m below an ultraviolet light bulb 3. At this stage, shutter 2
covers the entire surface of the dial, and the dial is not exposed to ultraviolet light. Next, the shirt It-2 is opened at a speed of about 2 strokes/sea. At this time, the coating layer 1a is gradually exposed to ultraviolet rays from the right end, and as a result, the coating layer 1a is gradually hardened from the right end. As the paint layer hardens, volumetric shrinkage 3- occurs, but as the uncured resin on the left side of the hardened portion is drawn towards it, there is a gap between the paint layer 1α and the dial board due to resin contraction. Almost no stress occurs. After the shutter 2 was fully opened and the entire surface of the coating layer 1a was exposed to the ultraviolet rays, the ultraviolet rays were further irradiated for about one minute. When the painted surface is cured using the above method, this clear coating has sufficient adhesion strength, and the printing layer does not crack or stop peeling over time, completing a dial with sufficient quality as an exterior component. I was able to do something.

As described in the examples above, according to the present invention, even if the entire dial surface is coated with ultraviolet curable resin, the internal stress generated between the paint layer and the dial substrate is extremely small, resulting in excellent quality. It is possible to obtain many effects such as being able to obtain a painted dial plate.

[Brief explanation of the drawing]

The drawing shows that a clear coating layer is formed on the P dial according to the present invention,
FIG. 3 is a cross-sectional view showing a state in which the printed layer is cured while opening the shutter. 4-1...Fist dial 1α...Clear paint layer 2...Shutter 3 @ @ * @ Ultraviolet lamp or above Applicant Daini Seikosha Co., Ltd. Agent Patent Attorney Mogami 5-

Claims (1)

[Claims] A transparent UV-curable resin is applied to the dial surface, and a shutter installed near the dial surface between the dial and the UV rays is gradually opened, and UV rays begin to be irradiated from one end of the painted surface, coating the paint layer at the edges. A watch dial with a Schiffleer paint layer formed through a process that gradually hardens the parts.