JPS59175534A - Formation of white diffusion film for tubular bulb - Google Patents

Abstract

PURPOSE:To prevent both discoloration of white diffusion film and deterioration of the work environment even after lighting for a long time, by using co- polymer emulsion resin consisting of acetic vinyl and ethylene as bonding agent for white pigment. CONSTITUTION:A white diffusion film is formed, by coating a glass globe internal surface with a suspension formed by dispersing white pigment within a water solution of co-polymer emulsion resin, consisting of vinyl and ethylene and drying. Co-polymer emulsion resin consisting of acetic vinyl and ethylene is chemically stable, also mechanically excellent, and operational quality is good. Therefore, the diffusion film obtained by using this material is excellent in weather resistant characteristics and even if accepting illumination of ultraviolet rays emitted from a fluorescent tube for a long time, it does not discolor at all.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for forming a white diffusion film for a tube.

Conventional Structures and Problems Fluorescent lamps have traditionally been used in large quantities not only in factories and shops but also in ordinary households because of their higher luminous efficiency than incandescent lamps.

However, in general, most fluorescent lamps are linear or annular in shape, and are bulkier than light bulbs, and require a ballast and lighting tube, so the entire device becomes bulky. Their disadvantages are that they are larger and more difficult to handle than light bulbs.

In recent years, in order to eliminate these disadvantages of fluorescent lamps, bulb cap-shaped fluorescent lamps have been developed in which the fluorescent tube is formed into a U-shaped hollow shape and incorporated into a glass globe, and the ballast and lighting tube are integrated. Lamps have been put into practical use.

In this case, a white diffusion film is formed on the inner surface of the glass globe so that the light from the built-in fluorescent tube is uniformly diffused. This formation has traditionally been done by applying a suspension of a white pigment used in ordinary fluorescent lamps, etc., to the inner surface of a glass globe using a suspension in an organic solvent containing a binder, such as nitrified cotton. methods are being adopted.

However, when such a method is adopted, if the light is turned on for a long time, the nitrified cotton in the white diffusion film turns yellow due to the ultraviolet rays emitted from the fluorescent tube housed in the lid inside the glass globe and heat. This causes the problem that the entire film turns yellow, impairs its appearance, and greatly reduces the luminous flux.
Furthermore, since organic solvents are used, there are problems in that the working environment is poor and the costs are high.

Purpose of the Invention The present invention has the advantage that there is no discoloration of the white diffusion film even when the light is turned on for a long time.
Further, the present invention provides a method for forming a white diffusion film for a bulb, which improves the working environment and reduces costs.

Structure of the Invention The method of forming a white diffusion film for a tube according to the present invention involves dispersing a white pigment in an aqueous solution of vinyl acetate and ethylene copolymer emulsion resin. Liquid A is applied to the inner surface of a glass globe and dried to form a white diffusion film on the inner surface.

Description of Examples In general, when using the so-called wet coating method employed in the method of the present invention, it is particularly important to select a binder. In other words, it is important to select a binder that will not discolor or deteriorate even when exposed to ultraviolet rays for a long period of time. It is necessary to select.

The inventors investigated various binders and found that vinyl acetate and ethylene copolymer emulsion resin were suitable as the binder.

Vinyl acetate and ethylene copolymer emulsion resin is
Chemically stable and other emulsion resins.

It has good compatibility with plasticizers, solvents, etc., and has excellent mechanical properties and good workability. It has particularly excellent water resistance, adhesion, alkali resistance, and pigment dispersibility. In other words, the diffusion film obtained using this method does not dissolve in water at all, does not fall off from the glass globe even if it gets wet, and has excellent weather resistance, so it can fluoresce for a long time. It was observed that there was no discoloration at all even when exposed to ultraviolet rays emitted from the tube.

Furthermore, since the emulsion resin can use water as a solvent, it has the advantage of being completely harmless to the human body, improving the working environment and lowering costs.

Generally, when forming a film using a suspension using an emulsified water-soluble polymer as a binder, a surfactant (antifoaming agent) is added because the suspension has a high foaming property. Usually this is 100 to 1
By adding 1000 Pp to the white pigment solid content in the suspension, a homogeneous and smooth coating can be stably obtained. In implementing the method of the present invention, the inventors
As a surfactant, an acetylene nonionic surfactant (trade name: Zarfinol PC, manufactured by Nissin Chemical Co., Ltd.) was used.

The present invention will be explained in detail below.

Example 1 Calcium phosphate 2.0KjI colloidal phosphoric acid 0.1! Vinyl acetate and ethylene copolymer emulsion resin (Sumitomo Chemical Co., Ltd. product name: Sumikaflex) 2. OK
y Deionized water 2・○ Tasurfinol Pc aqueous solution (10% concentration) 6om,
6 After thoroughly stirring the above materials with a stirrer,
Prepare the suspension by passing it through a mesh sieve. Using the prepared suspension, apply it to the inner surface of a spherical glass globe with an inner diameter of 10 boxes, at a temperature of approximately 80'C, and at an air volume of 500 m.
A white diffusion film was formed on the inner surface of the glass globe by blowing hot air of 1/IJ) to dry it. The obtained white diffusion film had a smooth film surface and an extremely pleasant appearance.

Then, a 10 watt type hollow-shaped fluorescent tube was incorporated into the glass globe to produce a light bulb-metal fluorescent lamp with an integrated ballast and lighting tube.

When the fluorescent lamp was turned on and the condition of the white diffusion film was observed after 6000 hours of lighting, no yellowing was observed in the film and no peeling of the film occurred.

Example 2 Barium carbonate 2.5 Kl Vinyl acetate and ethylene copolymer emulsion resin 2. OK! Deionized water 2. OK Tasurfinol PC aqueous solution (10% concentration) 70ml The above materials were placed in a pot mill and ground in a ball mill for 6 hours.

After pulverization, use the suspension to create a tube with an inner diameter of 10 cm and a height of 9.
It was applied to the inner surface of a 5CTL cylindrical glass globe and dried by blowing warm air at a temperature of about 60°C and a flow rate of soom #7' seconds to form a white diffusion film on the inner surface of the glass globe. The white diffusion film had a smooth film surface and an extremely good appearance.

Then, a 10 watt type hollow-shaped fluorescent tube was incorporated into the above glass globe to produce a light bulb base-shaped fluorescent lamp in which a ballast and a lighting tube were integrated.

When this fluorescent lamp was turned on and the condition of the white diffusion film was observed after 6000 hours of lighting, it was found that the same as in Example 1 was found.
No yellowing was observed in the film, and no shedding of the film had occurred yet.

In the above, an example was explained in which the method of the present invention was applied to the formation of a white diffusion film on the inner surface of a glass globe for a metal-shaped fluorescent lamp. Of course, it can also be applied to the formation of a white diffusion film on the inner surface of a glass globe (outer bulb) for a discharge lamp.

As described in detail, the present invention does not cause yellowing of the white diffusion film even when the light is turned on for a long time, and it also improves the working environment and reduces costs compared to the conventional method. A method for forming a white diffusion film for a tube can be provided.

Claims (1)

[Claims] A tube for a tube, characterized in that a suspension in which a white pigment is dispersed in an aqueous solution of vinyl acetate and ethylene copolymer emulsion resin is applied to the inner surface of a glass globe and dried to form a white diffusion film on the inner surface of the glass globe. How to form a white diffusion film.