JPS58126658A - Fluorescent lamp and its manufacture - Google Patents

Abstract

PURPOSE:To make a phosphor layer to adhere to the inner wall of a glass tube with an increased adhesive strength by making the phosphor layer to contain an adhesive-strength increasing agent which contains strontium oxide and/or barium oxide as well as boric anhydride and/or calcium pyrophosphate. CONSTITUTION:The inner wall of a glass tube for a fluorescent lamp is coated with a phosphor layer containing an adhesive-strength increasing agent, which contains at least one compound chosen from the groups consisting of strontium oxide and barium oxide nd at least one compound chosen from the groups consisting of boric anhydride and calcium pyrophosphate. In the above phosphor layer, it is recommendable that the adhesive-strength increasing agent contains 0.02-0.6wt% of SrO or BaO, 0.05-2.5wt% of B2O3 and 1-5wt% of Ca2P2O7. In addition, it is most preferred that the adhesive-strength increasing agent contains 0.05-0.4wt% of SrO or BaO, 0.1-1.0wt% of B2O3 and 2-4wt% of Ca2P2O7.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in the manufacturing method of fluorescent rungs and fluorescent lamps, and in particular to improvements in the adhesive strength of a fluorescent layer to the inner surface of a glass tube in a straight fluorescent lamp. It is about increase.

Conventionally, when applying a phosphor to the inner surface of a glass tube for a straight fluorescent lamp, for example, the phosphor is suspended in a solution of nitrocellulose as a binder dissolved in butyl acetate, an organic solvent. The liquid is applied to the inner surface of the glass tube, and a phosphor layer is formed through a drying and firing process. However, in recent years, water-soluble binders such as carboxymethyl cellulose, polyethylene oxide, and hydroxyalkyl cellulose have been used as this binder from the viewpoint of resource saving, energy saving, environmental issues, and the like. When attaching a phosphor to the inner surface of a glass tube for a straight fluorescent lamp, suspend the phosphor in a solution of the above-mentioned water-soluble binder dissolved in water, and apply this suspension to the glass tube. The phosphor layer is formed by coating the inner surface of the membrane, drying and firing process. However, in general, water-soluble binders have a weaker strength than organic binders in adhering the phosphor layer to the inner surface of the glass tube, making them extremely easy to peel off. For this reason, when a water-soluble binder is used, a small amount of an adhesive strength increasing agent is usually added to the phosphor suspension, which has the effect of firmly adhering the phosphor layer to the inner surface of the glass tube. Examples of adhesive strength increasing agents include barium nitrate, nitrates of alkaline earth metal elements such as calcium nitrate (see % Publication No. 51-41653), barium nitrate, barium nitrate, and ammonium nitrate (Japanese Patent Publication No. 47-29180).
), finely divided calcium pyrophosphate, finely divided inorganic compounds such as alumina, etc. are known.

However, when the phosphor and the adhesive strength enhancer are suspended in a solution in which the water-soluble binder is dissolved in water,
When this suspension was applied to the inner surface of a glass tube for a straight fluorescent lamp and a phosphor layer was formed through a drying and baking process, the adhesive strength of the phosphor layer to the inner surface of the glass tube was sufficient. However, the phosphor layer sometimes peeled off from the glass tube.

In 4I, polyethylene oxide among the above-mentioned water-soluble binders was used, and in the case of 7', the peeling phenomenon was noticeable.Furthermore, a transparent conductive coating such as tin oxide was applied to the inner surface of the glass tube using a water-based binder. When a phosphor layer was formed on the inner surface of a glass tube for a rabbit-start type fluorescent lamp, the above-mentioned peeling phenomenon also occurred conspicuously. Some kind of countermeasure is desired.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a phosphor rung in which the phosphor layer has a high contact strength with the inner surface of a glass tube, and a method for manufacturing the phosphor rung.

In order to achieve the above object, in the present invention, a phosphor layer containing a contact strength increasing agent consisting of strontium oxide and/or barium oxide and boric anhydride and/or calcium pyrophosphate is provided on the inner surface of the glass shell. It is characterized by the construction of a light-emitting light rung. Furthermore, by selecting the content of the adhesive strength increasing agent within the optimum range, a fluorescent lamp having a phosphor layer that is excellent not only in adhesive strength but also in other #1 characteristics can be constructed.

In order to manufacture such a fluorescent lamp, a phosphor, strontium nitrate and/or barium nitrate, and at least one selected from the group consisting of boric acid, boric anhydride, and calcium pyrophosphate are added to the water-soluble binder aqueous solution. or a phosphor suspension prepared by further adding ammonium nitrate to the inner surface of the glass tube, and a subsequent drying step. The method is characterized in that a fluorescent lamp is manufactured through a firing process.

Furthermore, by selecting the addition rate of the YF11 strength enhancer in the manufacturing process within an optimal range, it is possible to manufacture a phosphor rung having a phosphor layer that is excellent not only in adhesive strength but also in other characteristics.

The above-mentioned structure and manufacturing method of the present invention make it possible to extremely increase the adhesion strength of the phosphor layer to the glass tube. It has become possible to manufacture it easily and at low cost.

Hereinafter, the present invention will be described in detail by way of examples.

EXAMPLE 0.0% of polyethylene oxide as a water-bathable binder.
An aqueous solution of 8% by weight is used. Add halophosphate phosphor (white) to 150 cc of this polyethylene oxide water bath solution.
Add 100g. and - strontium nitrate (Sr(NOx)*) and/or barium nitrate (Ba(NOx)) as a bonding strength increasing agent and boric anhydride (BtO
s), boric acid (HsBOs), and at least one selected from the group consisting of calcium pyrophosphate (CatPtOy); Create a strength enhancer. A predetermined amount of this contact 7#@ power increasing agent is added to the polyethylene oxide aqueous solution to which the phosphor has been added. Thereafter, this solution is ball milled for 30 minutes to prepare a phosphor suspension. This suspension is applied to the inner surface of a 40W straight pipe glass tube. The glass tube is then dried and fired under normal conditions. Thereafter, a fluorescent rung was manufactured through a normal manufacturing process.

Table 1 shows the adhesive strength and lamp luminous flux of the source lamp to which a substitute combination of contact layer strength increasing agents among the various combinations of contact layer strength increasing agents described above was added. Here, the adhesive strength in Table 1 is defined as follows. In other words, as a guide to express the strength of the phosphor layer in contact with the inner surface of the glass tube, the peeling of the phosphor layer that occurs when an impact is applied to the outer surface of the phosphor rung with a piano wire with a load of 150 g. The size of the diameter is divided by the average diameter (mφ). In addition, the Lang luminous flux is at the initial stage of lighting (O
Total luminous flux (tm) of h) and after 100 hours of lighting (100h)
The total luminous flux (1 m ) of Oh is measured, and the decrease in the total luminous flux during this period is expressed as a percentage of the total luminous flux of Oh. Further, the amount of the adhesive strength enhancer added is expressed in terms of weight relative to the phosphor.

In Table 1, fluorescent lamp numbers 1 to 4 are fluorescent lamps of conventional construction shown for comparison with fluorescent lamp numbers 5 to 18 according to this embodiment.

The method of manufacturing fluorescent lamps Nos. 1 to 4 is exactly the same as the method of manufacturing fluorescent lamps Nos. 5 to 18 of this embodiment, except for the adhesive strength increasing agent. Lamp number 1 is a lamp without the addition of adhesive strength enhancer.

The adhesive strength of this lamp was 50 .phi., and the peeling phenomenon was so great that it could not be put to practical use. Lamp number 2 is a lamp in which the adhesive strength enhancer is only Btus. The adhesive strength of this lamp was 45saIφ, which made it impossible to put it into practical use. Lamp number 3 is a rung with only S r (NOs)x,
Although the adhesive strength is 25 φ, it cannot be put to practical use.

Rung number 4 is a lamp using only CavPtOt, but it cannot be put to practical use any longer.

On the other hand, lamp number 5 is 5 as adhesive strength enhancer.
This lamp contains 0.3% by weight of r(NOs)t and 0.2% by weight of BtOs. The adhesive strength of this lamp was 10 .phi., and the peeling phenomenon was small, so it was sufficiently usable for practical use. Moreover, the lamp luminous flux and its rate of decline are almost the same as rung number 1. Lamp number 6 is Ba (NOx)m O-5% by weight and H, B
The lamp added 1% by weight of OIo has a small peeling phenomenon and has a superior lamp luminous flux compared to lamp No. 1. Lamp number 7 is 5r (NOs)* 0-3 weight-
and 8.0.0.5% by weight, and its adhesive strength is 6101φ, which is small. Lamp number 8 is Ba (NO,), 0.7 weight - and B to
The lamp contains 1.5% by weight of m, and its adhesive strength is extremely excellent at 0-φ.

However, the lamp luminous flux and its rate of decline are slightly inferior.

Lamp number 9 is Ba (NOI)! O-5 weight- and H
The lamp contains 1% by weight of sBOsO and 2% by weight of C-Pm0y, and its adhesive strength is extremely excellent. Lamp number 10 is Sr (NOa) * 0.3% by weight, B, 0° 0.5% by weight, and NH4N0111JL
*The adhesive strength of the lamp is extremely high.

Lamp numbers 11 to 17 also have very low adhesive strength;
It is a lamp that can be fully put to practical use. Lamp number 18 is Sr (NOs) * 0.1wt- and B a (NOa
) t +0.1 wt% and B tOs 0.2 wt'i
This lamp contains 0.2% by weight of PtHaBOa, 1% by weight of CatPtOy, and NH4N011 by weight, and its adhesive strength is extremely excellent, and the lamp luminous flux and its rate of decline are slightly inferior to lamp number 1. It is.

As described above, the lamps designated by rung numbers 5 to 18 according to the present invention all exhibit adhesive strengths of 10 .phi. or less, and are much superior to the lamps designated by lamp numbers 1 to 4. Moreover, the lamp according to the invention differs little in lamp luminous flux and its rate of decline compared to conventional lamps.

In addition, when experiments were conducted in which the addition rate of the adhesive strength increasing agent was varied, the following findings were found. That is,
The addition rate of 5r(Nos)t and Ba(NOsL is 0.
A range of 0.05 to 1.0 weight is desirable. The reason for this is that when the addition rate is less than 0.05% by weight, it is undesirable because it causes a decrease in adhesive strength, and when it exceeds 1.0% by weight, the adhesive strength improves, but the discharge starting voltage of the fluorescent rung tends to increase. Undesirable because it shows. Further study revealed that the most preferable addition rate range was 0.1 to 0.7 weight. Further, the addition rate of Btus and HsBOm is preferably in the range of 0.05 to 25% by weight.

The reason for this is that when the addition rate is less than 0.05% by weight, it is undesirable because it causes a decrease in adhesive strength, and when it exceeds 25% by weight, it is undesirable because the adhesive strength improves but the Lang luminous flux decreases. However, the most preferable addition rate range was 0.1 to 1.0 weight. Further, it is desirable that the addition rate of CatPtOy is in the range of 1 to 5% by weight. The reason for this is that if the addition rate is less than 1 drop by weight, this is undesirable because it causes a decrease in adhesive strength, whereas if the addition rate exceeds 5 by weight, the adhesive strength increases proportionally, but the luminous flux of the lamp decreases, which is undesirable. Further study revealed that the most preferable addition rate range was 2 to 4 weight. The specific surface area of CatPmOy used in this example was 18,500 cf as measured by the plain air permeation method.
IIng's. Further, when N H4N Os is added, the addition rate is preferably in the range of 0.1 to 2 by weight. The reason for this is that if the addition rate is less than 0.1% by weight, it will not contribute to improving the adhesive strength, which is undesirable, and if it exceeds 2% by weight, the adhesive strength will be improved, but it will have a negative impact on Lang properties, which is undesirable. do not have. After further investigation, the preferred addition rate range for sharks was 0.5 to 1.
．． 5 weight.

By the way, the above-mentioned S'(NOs)*e Ba(N
Os )t 5HsBO, exists entirely as an oxide in the phosphor layer after the firing process, and SrQ, BIO, B
Performs IO1. Also, N Ha N Os is not present in any form in the phosphor layer after the firing process and is completely eliminated during the firing process. And Sr (NOs)* is S
When it reaches rO, its weight decreases to 48.961, and Ba(N
When Os)* becomes BaO, its weight decreases to 5&67%, and when HsBC)s becomes B, 03, its weight becomes 56.3
Reduced to 11.

Previously, the adhesive strength enhancer in the phosphor layer was Sr.
O and/or BaO and Btus and/or Ca
*It consists of P Go Ov. The desirable content ranges from 0.02 to 0.6% by weight of 8rO or BaO, and 0.05 to 2.0% by weight per BIO. ．． 5% by weight and CatPloy ranges from 1 to 5% by weight. Moreover, the most preferable content range is 8rO
The weight of BaO, 05~0.4 weight, B
2O2 is 0.1 to 1.0 weight, and carbon concentration is 2 to 4 weight.

In addition, although the above-mentioned example showed the case where polyethylene oxide was used as a water-soluble binder, almost the same effect was obtained even if other water-soluble binders were used. Furthermore, in the above embodiment, an example of a straight tube 40W 2 fluorescent lamp was described, but the same can be applied to a 2-pit start type fluorescent lamp having a transparent conductive coating on the inner surface of the glass tube, or a small 4 or 6.8W fluorescent lamp. Needless to say, this result was obtained.

Claims (1)

[Scope of Claims] (2) A fluorescent light containing an adhesive strength increasing agent consisting of at least one member selected from the group consisting of strontium oxide and barium oxide and at least one member selected from the group consisting of boric anhydride and calcium birophosphate. A fluorescent lamp characterized by having a body layer on the inner surface of a glass tube. 2 The content of the adhesive strength increasing agent to the phosphor in the phosphor layer is strontium oxide or barium oxide in the range of 0.02 to 0.6% by weight, boric anhydride in the range of 0. 05-25% by weight and calcium birophosphate is in the range 1-5% by weight. 1 The content of the adhesion strength increasing agent to the phosphor in the phosphor layer is strontium oxide or barium oxide in the range of 0.05 to 0.4% by weight, and boric anhydride in the range of 0.1 to 1% by weight. A fluorescent lamp according to claim 1, characterized in that the calcium birophosphate is in the range 2 to 4% by weight. 4. Adhesive strength consisting of a water-soluble binder aqueous solution, a phosphor, at least one selected from the group consisting of strontium nitrate and barium nitrate, and at least one selected from the group consisting of boric acid, poric anhydride, and calcium birophosphate. a step of applying a phosphor suspension prepared by adding an increaser to the inner surface of a glass tube; and a step of blowing warm air into the glass tube to dry it after the application step;
4. After the drying step, the glass tube is heated and fired. A method of manufacturing a fluorescent lamp. & The addition rate of the adhesive strength increasing agent to the phosphor is 0.05% of strontium nitrate or barium nitrate.
-1.0% by weight, boric acid or boric anhydride in a range of 0.05-5% by weight, and calcium birophosphate in a range of 1-5% by weight. Patented method for manufacturing fluorescent lamps. 6. The addition ratio of the adhesive strength increasing agent to the phosphor is strontium nitrate or barium nitrate from 0.1 to
0.7% by weight of acetic acid, boric acid or boric anhydride.
5. The method for producing a fluorescent lamp according to claim 4, wherein the amount of calcium pyrophosphate is 2 to 4. 7. The method for manufacturing a fluorescent lamp according to any one of items 4 to 6, wherein the water-soluble binder is made of polyethylene oxide. & An adhesive comprising a phosphor in a water-soluble binder aqueous solution, at least one selected from the group consisting of strontium nitrate and barium nitrate, at least one selected from the group consisting of boric acid, boric anhydride, and calcium pyrophosphate, and ammonium nitrate. A step of applying a phosphor suspension prepared by adding a strength increasing agent to the inner surface of a glass tube, a step of blowing warm air into the glass tube to dry it after the above coating step, and a step of drying the above-mentioned drying step. A method for manufacturing a fluorescent lamp, which comprises the steps of heating and firing the glass tube after the heating. 9. The addition rate of the adhesive strength increasing agent to the phosphor is 0.05% of strontium nitrate or barium nitrate.
~1.0 wt., boric acid or boric anhydride in the range of 0.05 to 25 wt., calcium pyrophosphate in the range of 1 to 5 wt., and ammonium nitrate 0.1 wt. 9. The method for manufacturing a fluorescent lamp according to claim 8, wherein the fluorescent lamp has a weight in the range of .about.2 weight. Imaginary, the addition ratio of the adhesive strength increasing agent to the phosphor is 0.1 to 0.1 to 0.1 to 0.1 to 0.1 to
0.7 weight range, boric acid or phosphoric anhydride ranges from αl to 1.0 weight weight, calcium pyrophosphate ranges from 2 to 4 weight weight, and ammonium nitrate 0.7 weight range. 9. The method for producing a fluorescent rung according to claim 8, characterized in that the weight is in the range of 5 to 1.5. U. The method for manufacturing a fluorescent lamp according to any one of items 8 to 10, characterized in that the water-soluble binder is made of polyethylene oxide.