JP2008123829A - Binder and fluorescent lamp using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a binder, along with a fluorescent lamp that uses the binder, capable of improving the degradation of phosphor under baking. <P>SOLUTION: If zinc phosphate with an average particle size of 0.5-10.0 μm is used as a binder for a fluorescent lamp, since binding force will not be degraded, even if the baking temperature is lowered, when manufacturing the fluorescent lamp, the baking temperature can be lowered; and thereby, degradation of phosphor under baking can be improved. The fluorescent lamp that uses the binder has a strong binding force between the phosphor and a glass tube and ensures a superior light flux for a lamp. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a binder and a fluorescent lamp using the same, and more particularly to a binder capable of improving phosphor deterioration due to baking and a fluorescent lamp using the same.

  In general, fluorescent lamps are prepared by pouring a phosphor suspension (phosphor coating solution) in which a phosphor is suspended in a high-viscosity solution (vehicle) in which a binder is dissolved in a solvent into the inner surface of a glass bulb, and uniformly coating and drying. It is produced by baking this at around 600 ° C. The phosphor coating liquid is roughly classified into an organic system using an organic solvent and an aqueous system using water depending on the type of solvent used.

  In the fluorescent lamp, a binder is generally used for the purpose of preventing the formed phosphor layer from peeling from the glass bulb. In many cases, the binder is added to the phosphor coating solution and used rarely mixed with the phosphor or attached to the surface thereof.

Known binders added to the phosphor coating solution include calcium borate / barium, calcium pyrophosphate, and alumina. These binders are used as a slurry of fine particles. Also known as binders that are attached to and mixed with phosphors are alkaline earth phosphates or borates, aluminum chloride, or mixtures thereof as disclosed in, for example, JP-A-63-289087. ing. Further, a frit glass of calcium pyrophosphate and calcium tetraborate or a water-resistant low-melting glass composition [Ln ₂ O ₃ —MnO—B ₂ O ₃ (Ln is Y or lanthanoid, M is Mg, Ca, Sr, Ba and // Zn] is also known.

At the time of manufacturing the fluorescent lamp, as described above, the phosphor layer is formed by baking at around 600 ° C. However, there is a problem that the phosphor is oxidized in the baking process and the luminous efficiency is lowered. When the baking temperature is lowered for this problem, the conventional binder has a new problem that the binding force is reduced and the phosphor layer is easily peeled off by impact.
JP-A-63-289087

  The present invention has been made to solve such problems. The objective of this invention is providing the binder which can improve the fluorescent substance deterioration by baking, and a fluorescent lamp using the same.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by using a specific zinc phosphate as a binder, and have completed the present invention. .

(1) The binder of the present invention is a zinc phosphate having an average particle size in the range of 0.5 to 10.0 μm in a binder used for bonding a fluorescent lamp glass tube and a phosphor. It is characterized by being.

(2) The binder of the present invention is the binder according to (1), wherein the zinc phosphate reacts an aqueous solution of a zinc compound and an aqueous solution of a phosphate in a temperature range of 10 to 70 ° C. It is characterized by being obtained by calcining the precipitate formed by firing in a temperature range of 100 to 500 ° C.

(3) The binder slurry of the present invention is a binder slurry obtained by using the binder described in (1) or (2), and the slurry has a center particle size of 5.0 μm or less. It is characterized by being.

(4) The fluorescent lamp of the present invention is a fluorescent lamp using the binder described in (1) or (2).

(5) The fluorescent lamp of the present invention is characterized in that the binder of (1) or (2) is contained in the phosphor layer of the fluorescent lamp in an amount of 6% by weight or less based on the phosphor.

(6) In the fluorescent lamp of the present invention, the phosphor layer of the fluorescent lamp contains the binder according to (1) or (2) and fine calcium phosphate, and the sum thereof is 6% by weight or less with respect to the phosphor. It is characterized by being.

  When the binder of the present invention is used in a fluorescent lamp, the binding temperature does not decrease even when the baking temperature at the time of producing the fluorescent lamp is lowered, so that the baking temperature can be lowered, and thereby the phosphor is deteriorated by baking. Can be improved. In addition, the fluorescent lamp using the binder of the present invention has a strong binding force between the phosphor and the glass tube and has an excellent lamp luminous flux.

  Embodiments of the present invention will be described below. However, the embodiment described below exemplifies a binder for embodying the technical idea of the present invention and a fluorescent lamp using the same, and the present invention uses the binder and the same. The fluorescent lamp is not specified as follows.

  Here, the manufacturing method of the binder which concerns on one embodiment of this invention is demonstrated in detail. First, a water-soluble zinc compound is dissolved in pure water, and the temperature of the aqueous solution is adjusted to 10 to 70 ° C. Moreover, water-soluble phosphate is melt | dissolved in a pure water, and the temperature of aqueous solution is adjusted to 10-70 degreeC. Next, both aqueous solutions are mixed and reacted to obtain a zinc phosphate precipitate. This is solid-liquid separated, dried, and then fired in a temperature range of 100 to 500 ° C. The fired product is coarsely pulverized to obtain zinc phosphate powder. This zinc phosphate powder and nitrocellulose / butyl acetate solution are mixed and sufficiently pulverized by a ball mill or the like to obtain a binder slurry.

  The average particle size of the zinc phosphate powder is preferably in the range of 0.5 to 10.0 μm. When the average particle size is smaller than 0.5 μm, the particles are aggregated and become higher in viscosity when made into a slurry, and conversely when larger than 10.0 μm, the binding force is lowered. A more preferable range is 0.5 to 5.0 μm. Here, the average particle diameter is a value measured using a Fischer sub-sieve sizer (FSSS) by the air permeation method.

  The temperature at which the aqueous zinc compound solution reacts with the aqueous phosphate solution is preferably in the temperature range of 10 to 70 ° C. If the reaction temperature is lower than 10 ° C., the particles become fine particles. Conversely, if the reaction temperature is higher than 70 ° C., the particles become coarse particles.

  The temperature for firing the precipitate of zinc phosphate is preferably in the temperature range of 100 to 500 ° C. When the firing temperature is lower than 100 ° C., the luminous flux of the lamp is lowered, and conversely when it is higher than 500 ° C., the particle size of the binder is increased. A more preferable range of the firing temperature is 150 to 450 ° C.

  The center particle size of the binder slurry is preferably 5.0 μm or less. When the center particle size is larger than 5.0 μm, the binding force is lowered. A more preferable range of the center particle diameter of the slurry is 0.5 to 3.0 μm, and a more preferable range is 0.5 to 2.0 μm. Here, the center particle size of the binder slurry is a value measured using a laser diffraction particle size measuring device.

  The binder slurry is prepared in the range of 3 to 30% by weight in terms of solid content. This is because if the concentration is lower than 3% by weight, a large amount of binder slurry must be added, and the concentration of the phosphor-coated slurry decreases. Conversely, if the concentration is higher than 30% by weight, it is difficult to disperse.

  The fluorescent lamp of the present invention is manufactured by the following method. First, the phosphor is suspended in a nitrocellulose / butyl acetate solution, and the binder slurry of the present invention is added thereto and mixed to obtain a phosphor coating slurry. The zinc phosphate binder contained in the phosphor coating slurry is 6% by weight or less based on the phosphor. Next, the obtained phosphor-coated slurry is poured into the inner surface of the glass tube, and then dried by passing warm air through the glass tube, followed by baking, exhausting, attaching a filament, and attaching a base to obtain a fluorescent lamp. The fluorescent lamp is manufactured so that the amount of the phosphor attached is in the range of 4.5 to 5.0 g.

  There is an appropriate amount of the binder of the present invention, and if the amount added is more than 6% by weight with respect to the phosphor in the coating slurry, the lamp luminous flux decreases, which is not practical. That is, an appropriate amount of the binder is 6% by weight or less, preferably 0.5 to 5.0% by weight, more preferably 0.5 to 2.0% by weight with respect to the phosphor.

  Further, the binding force is further improved by using a binder of fine particle calcium phosphate in combination with a binder of zinc phosphate. However, if the amount of particulate calcium phosphate added is too large, there is a problem that the luminous flux of the lamp is lowered. The appropriate amount is the sum of the amount of zinc phosphate and the amount of particulate calcium phosphate being 6% by weight or less with respect to the phosphor. It is preferable to keep it below the amount of zinc acid.

  Examples of the present invention will be described below, but it goes without saying that the present invention is not limited to specific examples.

[Example 1]
<Binder and binder slurry>
ZnCl _{2 (} 206.4 g) is dissolved in pure water to 1.5 liters, and the solution temperature is adjusted to 50 ° C. to prepare a zinc chloride aqueous solution. Next, 4133.3 g of (NH ₄ ) ₂ HPO ₄ is dissolved in pure water to 1.5 liters and adjusted to a liquid temperature of 50 ° C. to prepare an aqueous ammonium phosphate solution. Next, a zinc chloride aqueous solution and an ammonium phosphate aqueous solution are mixed and reacted to obtain a precipitate of zinc phosphate. This is solid-liquid separated with Nutsche, and the solid content is dried at 90 ° C. for 15 hours. This is further baked in a muffle furnace at 450 ° C. for 2 hours. The fired product is coarsely pulverized to obtain the binder (zinc phosphate powder) of the present invention having an average particle size of 5.0 μm. Here, the average particle diameter of the binder is measured using a Fischer Sub Sheave Sizer (FSS) by an air permeation method. FIG. 1 shows an X-ray diffraction pattern of the obtained zinc phosphate powder. Next, 100 g of this zinc phosphate powder and 300 g of 1% nitrocellulose / butyl acetate solution are mixed and pulverized by a ball mill for 15 hours to obtain a binder slurry of the present invention having a center particle size of 1.7 μm. Here, the central particle size of the binder slurry is measured using a laser diffraction particle size measuring device.

<Fluorescent lamp>
BaMgAl ₁₀ O ₁₇ : Eu blue-emitting phosphor, LaPO ₄ : Ce, Tb green-emitting phosphor, and Y ₂ O ₃ : Eu red-emitting phosphor in a weight ratio of blue: green: red = 50: 20: 30 Mix in proportions. 31.5 g of this three-wavelength mixed phosphor is suspended in 40 g of a 1% nitrocellulose / butyl acetate solution, to which 4.2 g of the binder slurry of the present invention is added, and the whole is mixed uniformly by stirring sufficiently. And passing through a sieve to obtain a phosphor-coated slurry. The zinc phosphate binder contained in the slurry is 2% by weight with respect to the phosphor.

Next, the obtained phosphor coating slurry is uniformly poured into a fluorescent lamp glass tube having an outer diameter of 3 mm and a length of 400 mm, and dried with warm air to form a phosphor layer. Next, this is baked at a temperature of 580 ° C. for 5 minutes to remove the organic binder. After the glass tube is cooled, the inside of the glass tube is evacuated according to a usual method, a rare gas and mercury are enclosed, and an electrode is attached to obtain a fluorescent lamp. In this embodiment, the initial luminous flux of the fluorescent lamp is 18889 cd / m ² , and the chromaticity coordinate values are x = 0.2493 and y = 0.2134, which are equivalent to those of the fluorescent lamp using the conventional binder. It has the above excellent lamp luminous flux.

<Measurement of binding force>
The phosphor coating slurry is uniformly poured into a glass tube for an outer diameter of 32 mmφ40 watt fluorescent lamp and dried with warm air to form a phosphor layer. Here, the adhesion amount of the phosphor is adjusted to be in the range of 4.5 to 5.0 g per glass. Next, this is baked at a temperature of 580 ° C. or 500 ° C. for 5 minutes to remove the organic binder. After the glass tube is cooled, the binding force is measured.

The binding force is forcibly tested under stronger conditions than the actual conditions as follows in order to compare the peeling failure of the phosphor layer during exhaust. Air is blown out at a pressure of 1.2 kg / cm ² for 0.5 seconds from a nozzle having a 3 mmφ outlet at a position 5 mm away from the phosphor screen after baking, and the diameter of the phosphor layer blown off is measured. Therefore, the smaller the diameter, the stronger the binding force. In this example, the binding force is 26 mmφ when the baking temperature is 580 ° C., and 28 mmφ when the baking temperature is 500 ° C., and in any case, the binding force is stronger than the conventional binder. .

[Example 2]
Except that the firing temperature is 350 ° C., it is carried out in the same manner as in Example 1 to obtain the zinc phosphate binder and binder slurry of the present invention.

[Example 3]
Except for setting the firing temperature to 150 ° C., the same procedure as in Example 1 is carried out to obtain the zinc phosphate binder and binder slurry of the present invention.

[Comparative Example 1]
A mixture of 0.3 CaO · 0.7BaO · 1.6B ₂ O ₃ and Ca ₂ P ₂ O _{4 having} a weight ratio of 1: 1, which is conventionally known as a binder, is used. A cellulose / butyl acetate solution (300 g) is mixed and pulverized by a ball mill for 2 hours to obtain a binder slurry having a center particle size of 0.7 μm. The initial luminous flux of the fluorescent lamp produced in the same manner as in Example 1 using this binder slurry is 18322 cd / m ² , and the chromaticity coordinate values are x = 0.2478 and y = 0.2105.

  The results of measuring the binding force in the same manner as in Example 1 for the binder and the binder slurry obtained in Examples 1 to 3 and Comparative Example 1 are summarized in Table 1. Table 1 shows the average particle size of the binder and the central particle size of the binder slurry. From this table, it can be seen that Examples 1 to 3 have a higher binding force than the comparative example when the baking temperature is 580 ° C. or 500 ° C. As described above, when the binder of the present invention is used, since the binding force is large even when the baking temperature is lowered to 500 ° C., the baking temperature at the time of producing the fluorescent lamp can be lowered. And thereby, deterioration of the fluorescent substance by baking can be improved. In addition, the fluorescent lamp using the binder of the present invention has a strong binding force between the phosphor and the glass tube and has an excellent lamp luminous flux.

  As described above, when the binder of the present invention is used for a fluorescent lamp, the binding force does not decrease even when the baking temperature at the time of manufacturing the fluorescent lamp is lowered, and therefore the baking temperature can be lowered. The deterioration of the phosphor due to baking can be improved. Furthermore, by using the binder of the present invention, it is possible to provide a fluorescent lamp which has a strong binding force between the phosphor and the glass tube and has an excellent lamp luminous flux.

2 is an X-ray diffraction diagram of a binder obtained in Example 1. FIG.

Claims (6)

  A binder used for bonding a glass tube of a fluorescent lamp and a phosphor, wherein the binder is zinc phosphate having an average particle size in a range of 0.5 to 10.0 μm.   The zinc phosphate is obtained by firing a precipitate formed by reacting an aqueous solution of a zinc compound and an aqueous solution of phosphate in a temperature range of 10 to 70 ° C. in a temperature range of 100 to 500 ° C. The binder according to claim 1.   A binder slurry obtained by using the binder according to claim 1, wherein the slurry has a center particle size of 5.0 μm or less.   A fluorescent lamp using the binder according to claim 1.   A fluorescent lamp characterized in that the binder layer according to claim 1 or 2 is contained in the phosphor layer of the fluorescent lamp in an amount of 6% by weight or less based on the phosphor.   A fluorescent lamp characterized in that the phosphor layer of the fluorescent lamp contains the binder according to claim 1 or 2 and fine calcium phosphate, and the sum thereof is 6% by weight or less based on the phosphor.

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