JPS58155649A - Method of forming incandescent diffused film for tubular bulb - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming a white diffusion film for a light bulb, and more particularly to a method for forming a white diffusion film for a light bulb type fluorescent lamp having a light bulb base and incorporating a non-linear fluorescent lamp with two ballast lighting tubes. The present invention relates to a method for forming a white diffusion film on the inner surface of an outer globe.

BACKGROUND ART Fluorescent lamps have traditionally been used in large quantities not only in factories and shops but also in homes in Japan due to their much higher lamp efficiency than incandescent light bulbs. However, most fluorescent lamps have a linear or annular shape, which makes them larger than light bulbs and requires a ballast and lighting tube, making the entire device bulky and difficult to handle. A major drawback is that they are more complicated than light bulbs.

In recent years, in order to solve these drawbacks and to save power, so-called light bulbs have been developed, in which a fluorescent lamp is formed into a U-shape or a double-U shape, integrated with a lighting tube and a ballast, and housed in a glass globe. Many shaped fluorescent lamps have been proposed. In this case, a white pigment is applied to the inner surface of the globe so that the light from the built-in fluorescent lamp is evenly diffused, but the method of applying this white pigment is the same as conventionally used for incandescent light bulbs. Electrostatic coating methods using fine silica powder, etc., and wet coating methods, which use a suspension of a white pigment used in fluorescent lamps, etc., dispersed in an organic solvent containing a binder, such as nitrified cotton, are known. It is being

In compact fluorescent lamps, the inside of the globe is not exhausted and air is present, so the moisture contained therein adheres to the inner surface of the globe while it is lit.
It has been found that when the adhesion strength is extremely weak, such as fine silica powder applied to the inner surface of the glove using an electrostatic coating method, a part of the film falls off. On the other hand, in the case of a wet coating method using a suspension that uses nitrified cotton as a binder, if the light is turned on for a long time, the entire diffusion film will be damaged due to the ultraviolet rays emitted from the fluorescent lamp housed inside the glove. Disadvantages were discovered in that the appearance was impaired due to discoloration to yellow, and the luminous flux was greatly reduced.

The present invention provides a novel method for forming a white diffusion film for bulbs, which uses a wet coating method among the above two coating methods, and which does not cause any film shedding and does not change color even after being turned on for a long time. It is something to do.

When using the wet coating method, the important points are to select a solvent that has good pigment dispersibility, to select a stable binder that will not discolor even when exposed to ultraviolet rays for a long time, to select a binder that has strong film adhesion strength,
Furthermore, it is a solvent that is less toxic to the human body.

The inventors conducted experiments on various binders and found that ethyl cellulose was suitable. Ethylcellulose is a type of cellulose resin, but unlike nitrified cotton and trocellulose, it was confirmed that it does not change color at all even when exposed to long-term ultraviolet rays. Another great advantage of ethyl cellulose is that it is soluble in various organic solvents.

Among various solvents, as a result of testing solvents with low toxicity to the human body and good dispersibility, it was found that n-propanol and butyl acetate are suitable. Among these, butyl acetate has traditionally had the characteristics that the evaporation rate in a fluorescent run matches the drying rate during the formation of a diffusion film and that it is easier to handle than other acetates.

By the way, when a white diffusion film was formed on the inner surface of a glass globe using a suspension in which a white pigment was dispersed in a butyl acetate solution of ethyl cellulose or an n-propanol solution, the film surface was rough and there was a problem with the appearance in practical use. It has been found. After conducting various studies to improve the film surface, we found that the addition of a plasticizer was effective. There are various plasticizers, but as a result of experimental studies, we have found that silicone oil modified with amine groups is suitable.

As described above, using n-propanol or butyl acetate as a solvent and adding silicone oil modified with amine groups as a plasticizer, a suspension of a white pigment dispersed therein is used to coat the inner surface of a glass globe with a white color. As a result of forming the diffusion film, a homogeneous white diffusion film with high film adhesion strength and excellent ultraviolet resistance was easily obtained. It has been found that the optimum drying conditions in this case are warm air at a temperature within the range of 20 to 60°C, and the optimum air velocity is 1 to 1 Qm/sec. It has been found that when the temperature is outside the above range, drying is extremely slow or rapid, and in either case, numerous cracks occur on the film surface, resulting in a significant loss of appearance. On the other hand, if the wind speed is less than 1 m/sec, drying will be too slow and the membrane surface will become rough, while if it exceeds 10 m/sec, the membrane will be washed away before drying, resulting in film unevenness. were found to be inappropriate in both cases. As a result of actually applying a glass globe having a white diffusion film formed by the method according to the present invention to a compact fluorescent lamp, it was found that no discoloration occurred even after being lit for more than 6,000 hours, and there was no film falling off at all. It could be confirmed.

Examples of the present invention will be described in detail below.Example 1 Titanium oxide...3 to 9
Engineered cellulose s%n-7' lovanol solution...2.
5℃ n-glopanol ・・・・・・4j
2-amino group modified silicone! Oil...200m
j2 The above materials were placed in a ball mill pot and subjected to ball milling for 5 hours. Inner diameter using the prepared suspension? , 5crn, and the inner surface of a long cylindrical transparent glass globe with a length of 12crn for 1.5y. Drying was carried out by blowing warm air into the glove at a temperature of 45°C and a wind speed of 3 m for 7 seconds. A 9-watt U-shaped fluorescent lamp was incorporated into the globe together with a ballast and a lighting tube to produce a light bulb-shaped fluorescent lamp. Even when this lamp was turned on for eooo hours, no film came off at all, and no coloration occurred.

Example 2 Calcium phosphate ・・・・・・5 K9
Ethyl cellulose 6-thiacetate butyl solution...2.6
Butyl diacetate...4. (1
Amino group modified silicone oil...100m
After thoroughly mixing and stirring the above ingredients, a suspension was prepared through a 300 mesh sieve.

1.8) The prepared suspension was applied to the inner surface of a spherical transparent glass globe with an inner diameter of 1ocrn.

Drying was carried out by blowing warm air into the glove at a speed of about 40° C1 at a speed of 5 m for 7 seconds. Next, a 10 watt double U-shaped fluorescent lamp was installed in the globe along with a ballast and a lighting tube to produce a light bulb-shaped fluorescent lamp.

Even after this lamp was lit for 6,000 hours, no discoloration occurred and no film came off at all.

Example 3 Barium carbonate...5Kp engineered methyl cellulose s% 7' methyl acetate solution...30j
Butyl diacetate ・・・・・・・・・3. of
l Amino group-modified silicone oil ・・・・・15
The above materials were placed in a ball mill pot at 0 m°C, and ball milled for 6 hours. After ball milling, the circle diameter is 10
C1n + 2. inside a short cylindrical transparent glass globe with a height of 9.51M. Of was applied. Drying was carried out by blowing warm air into the glove at a speed of approximately 40"C2 at a speed of 6 m/sec.Next, a 10 watt double U-shaped fluorescent lamp was installed in the glove together with a ballast and lighting tube, and a light bulb-shaped A fluorescent lamp was made.

Even when this lamp was lit for 6,000 hours, no film came off at all, and no coloring occurred.

As explained above, the present invention can provide a novel method for forming a white diffusion film on the inner surface of a glove, which has particularly high adhesion strength and does not discolor. The effect is extremely large.

It should be noted that the present invention is not limited to the above-mentioned light bulb-shaped fluorescent lamps, but can of course also be applied to the formation of white diffusion films inside globes for general light bulbs and globes for high-pressure discharge lamps. .

Claims (1)

[Claims] 0) A white pigment containing ethyl cellulose and a silicone oil modified with an amine group together with butyl acetate or n-
A method for forming a white diffusion film for tubes, which comprises applying a suspension dispersed in propatool to the inner surface of a glass globe and drying it. ? 2) Air temperature during drying is 20~60''C9 wind speed is 1~
10. The method for forming a white diffusion film for a tube according to claim 1, wherein the speed is 10 m/sec.