JPS6331576A - Formation of film - Google Patents

Abstract

PURPOSE:To enhance appearance by suppressing pinhole-like exfoliation, by mixing a proper amount of a weak acid and polyoxyalkylene octyl ether with a suspension containing ultrafine particulate alumina. CONSTITUTION:A suspension forming a fluorescent film is prepared by further mixing a weak acid and polyoxyalkylene octyl ether with a mixture of a phosphor, a water soluble high-molecular resin, ultrafine particulate alumina with a particle size of 0.1 mum or less and water. By mixing glacial acetic acid as the weak acid in a ratio of 0.01-10 wt, the dispersibility of ultrafine particulate alumina can be enhanced still more. Further, by mixing 0.01-10 wt% of polyoxyalkylene octyl ether, the wettability of a glass bulb by the suspension is improved and a film having an excellent coating skin is formed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for forming a film, and in particular, a film formed by applying a phosphor suspension containing ultrafine alumina and polyethylene oxide to the inner surface of a glass bulb. This invention relates to improving the strength and appearance of phosphor coatings.

[Conventional technology]

In general, fluorescent lamps are manufactured by coating the inner surface of a glass bulb with a suspension of a mixture of phosphor, binder, solvent, binding agent, etc., drying it, and then baking it to form a phosphor coating. Manufactured through sealing, evacuation, and finishing processes.

Conventionally, nitrocellulose or ethylcellulose has been used as the binder, and organic solvents such as butyl acetate and kijirole have been used as the solvent. However, nitrocellulose itself is easily combustible;
It must be handled with care as there is a risk of spontaneous combustion.

In addition, organic solvents such as butyl acetate and kijirol are similarly highly flammable, requiring special safety measures, and combined with the high cost of organic solvents, there is the problem of high production costs. have.

In order to solve such problems, for example,
No. 37038 discloses a calcium halophosphate phosphor,
2 of polyethylene oxide with a molecular weight of 300,000 to 3,000,000
Aqueous solution at 30-200 CPS at 3°C and 1/2 to
A method of forming a phosphor coating by applying a 2:2 suspension to the inner surface of a glass bulb is disclosed.

According to this formation method, polyethylene oxide is soluble in water because it has hydrophilicity in the ether group, and is also soluble in organic solvents containing aromatic hydrocarbons. Since it completely decomposes and burns out at around ℃, it is difficult to leave carbon behind after firing, which can effectively improve the initial luminous flux, and there is little change in the suspension over time, making it easy to apply to mass production processes. You can expect excellent effects such as:

[Problem that the invention seeks to solve]

However, the phosphor coating made from a suspension containing polyethylene oxide has insufficient adhesion strength to the glass bulb, and mechanical shock to the glass bulb during the manufacturing process or after the product can cause the phosphor coating to spread over a wide area. range(
There is a tendency for the product to peel off over a large area or in the form of pinholes, thereby impairing its marketability.

For this purpose, ultrafine alumina particles (less than 0.1μ) are added to the suspension.
By mixing an appropriate amount of At2 o3), the adhesion strength of the phosphor coating to the glass bulb can be improved. However, pinhole-like peeling occurs during lighting, and problems with appearance remain to be solved.

This pinhole-like peeling is thought to be due to insufficient dispersibility of ultrafine alumina particles of 0.1 μm or less, which are intended to improve the adhesion strength of the phosphor coating to the glass bulb.

Therefore, an object of the present invention is to provide a method for forming a film that can maintain the appearance of a lamp without any practical problems by further increasing the dispersibility of ultrafine alumina particles.

[Failure to solve the problem]

Therefore, in order to achieve the above-mentioned object, the present invention includes a matrix, a water-soluble polymer resin, ultrafine alumina, and a glass bulb.
When forming a film by contacting a suspension containing water, 0.01 to 1% by weight of a weak acid that does not adversely affect the base material and 0.01% polyoxyalkylene octyl ether are added to the suspension. ~10% by weight is mixed.

However, if the amount of weak acid mixed is less than 0.01% by weight, the dispersion of ultrafine alumina particles will be insufficient, making it impossible to prevent pinhole-like peeling of the coating, and conversely, if the amount of weak acid mixed is less than 0.01% by weight, If the amount exceeds 0.01% by weight, the wetting effect (wetting effect of water on the pulp) is insufficient. However, if the mixing amount exceeds 10% by weight, foaming tends to occur, and contact between the suspension and the pulp will cause an adverse effect on film formation. Octyl ether should be set in the range 0.01-10% by weight.

[For production]

According to this invention, by mixing an appropriate amount of weak acid into a suspension containing ultrafine alumina particles, the dispersibility of the ultrafine alumina particles is made uniform. Therefore, the adhesion strength of the coating to the glass bulb is uniformized and improved. Therefore, pinhole-like peeling can be effectively prevented. Further, by mixing 0.01 to 10% by weight of polyoxyalkylene octyl ether, the wettability of the suspension to the pulp can be improved, thereby improving the application to the skin.

〔implementation? 1fl1 Next, an example of application of the present invention to FL4QSW will be described.

First, 1.0 kg of antimony and manganese activated calcium halophosphate phosphor and 1.0 kg of 2% polyoxyethylene oxide aqueous solution. O4, 10% ultrafine particle alumina suspension 2
00nt, contains glacial acetic acid, and has a viscosity of 90-100CP
Prepare SK-adjusted suspension. As shown in the table below, this suspension is classified into N011 to NO and 1Q depending on the amount of glacial acetic acid and polyoxyalkylene octyl ether mixed. Next, these suspensions are poured into an upright glass bulb and then dried with hot air at 70 to 80°C and 5 to 10 m/s.

Next, it is placed in a firing furnace set at 550°C and fired.

When observing the occurrence of pinhole-like peeling in the phosphor coating and the coated surface of the fluorescent lamps with these specifications, the results shown in the table above were obtained.

[Effects of the Invention As described above, according to the present invention, by mixing an appropriate amount of a weak acid and polyoxyalkylene octyl ether into a suspension containing ultrafine alumina particles, the dispersibility of ultrafine alumina and the suspension can be improved. Improved wettability. For this reason, pinhole-like peeling in the coating can be suppressed to an extent that does not cause any practical problems, and the appearance characteristics can also be effectively improved.

Claims (5)

[Claims] (1) When forming a film by bringing a suspension containing a base material, a water-soluble polymer resin, ultrafine alumina, and water into contact with a glass bulb, a weak acid that does not adversely affect the base material is added to the suspension. A method for forming a film, the method comprising mixing 0.01 to 10% by weight of polyoxyalkylene octyl ether and 0.01 to 10% by weight of polyoxyalkylene octyl ether. (2) The method for forming a film according to claim 1, wherein the weak acid is glacial acetic acid. (3) The method for forming a film according to claim 1, wherein the base material is a fluorescent material or a light reflecting member. (4) The method for forming a film according to claim 1, wherein the water-soluble polymer resin is polyethylene oxide. (5) The method for forming a film according to claim 1, wherein the particle size of the ultrafine alumina particles is 0.1 μm or less.