JPH01176693A - Manufacture of far infrared radiator - Google Patents

Abstract

PURPOSE:To get a far infrared radiator which is processed in a product cheaply and easily by applying sol solution made by hydrolyzing a metal alkoxide on a base material surface so as to be made to gel and is subjected to heat treatment. CONSTITUTION:Sol solution made by hydrolyzing a metal alkoxide is applied on a base material surface so as to be made to gel and it is subjected to heat treatment. As the metal alkoxide, the metal alkoxide of substitutional or non- substitutional type or a mixture thereof is used. With this arrangement, taking the metal alkoxide as a raw material, firm membrane can be formed by the heat treatment at comparatively low temperature, and thereby processing in a far infrared radiator can be performed cheaply and easily. In addition, selection degree of freedom of the base material is also high.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a far-infrared radiator made of ceramics or glass and used as a heating element.

Conventional technology and its problems Conventionally, heaters using far-infrared ceramics
Shapes such as tube, plate, and lamp shapes are known. These are manufactured by embedding a metal heating element inside ceramics or by plasma spraying ceramics onto a metal surface.

However, there are problems in that ceramics are difficult to process and plasma coating is very expensive.

The present invention can achieve
The purpose is to manufacture a far-infrared radiator that is easy to process into products and is inexpensive.

Means for Solving the Problems The present invention provides a far-infrared radiator characterized in that a sol solution obtained by hydrolyzing at least one metal alkoxide is applied to the surface of a base material, gelled, and heat-treated. The present invention provides a method for manufacturing.

The metal alkoxide used in the present invention includes substituted,
Unsubstituted metal alkoxides and mixtures thereof are used to hydrolyze the aqueous solution to obtain a sol solution.

The metal alkoxide may be one that forms a gel when dehydrated by heat treatment, such as silicon alkoxide, zirconium alkoxide, titanium alkoxide, aluminum alkoxide, boron alkoxide, sodium alkoxide, calcium alkoxide, nickel alkoxide, iron. Examples include alkoxides, copper alkoxides, cobalt alkoxides, manganese alkoxides, and the like, with silicon alkoxides, zirconium alkoxides, and titanium alkoxides being preferred.

Further, as the alkoxy group, a lower alkoxy group is preferable, and examples thereof include a methoxy group, an ethoxy group, a propoxy group, and the like. Therefore, the metal alkoxides include silicon tetraethoxide S i (OC2H5)4,
Silicon tetramethoxide 5i (OCR,).

Tetra-inopropoxy titanium Ti (iso-Ca
H2)t, trisec-butoxyaluminum, tetraisopropoxyzirconium Zr (OCaI2
)- etc. are preferred.

In addition, the alkoxy group of the above metal alkoxide is a lower alkyl group, an aliphatic hydrocarbon group such as a vinyl group, or an aromatic group such as a phenyl group, or a phenyl group substituted with a lower alkyl group such as methyl, ethyl or propyl group. It may be substituted with a hydrocarbon group, or an alkyl-substituted amino group substituted with a lower alkyl group such as a methyl, ethyl or propyl group.

As the aqueous solvent containing the metal alkoxide or the mixture of metal alkoxide and substituted metal alkoxide, a mixed solution of water and a lower alcohol such as methanol, ethanol, propanol, etc. is used.

In addition, hydrolysis catalysts include hydrochloric acid, sulfuric acid, ammonia aqueous solution,
Organic amines such as triethylamine are used.

When an aqueous solution consisting of a metal alkoxide and/or a substituted metal alkoxide is hydrolyzed to form a sol solution,
This can be carried out by adding the hydrolysis catalyst to these aqueous solutions and stirring at room temperature, but the hydrolysis reaction may also be accelerated by slightly raising the temperature. Further, the above hydrolysis reaction may be carried out by simultaneously adding and mixing a metal alkoxide, a substituted metal alkoxide, an aqueous solvent, and a hydrolysis catalyst.

Furthermore, it is preferable to add metal oxide powder to the sol solution because it improves film forming properties. As such a metal oxide, S
in,, Fat's, MgO, AL03, Cu 01Z
Examples include rOa, Tilt, N i O, and the like. Further, such powder preferably has a particle size Q of 1 to 1000 μm.

Then, the sol solution is applied to the substrate. As a substrate,
Any substrate conventionally used for a radiator, such as glass, iron, or aluminum plate, can be suitably used.

In addition to coating, spraying may be used to adhere the sol solution to the substrate, or the substrate may be immersed in the sol solution. The heat treatment is preferably carried out at 600 to 1200°C for about 10 hours.

Next, the present invention will be explained in more detail based on examples.

5i (OEt) 4208g, Zr (OCaH7) 480
9. 92 g of ethanol was stirred and mixed. Then, 0.0
18 g of 2N MCI was gradually added dropwise to react and hydrolyze. Next, add 5iOz powder (400mes
h) 609, Fetus powder (400mesh) 1
09, MgO powder (400mesh) 59 was added,
A sol solution was obtained by stirring for 2 hours and applying ultrasonic vibration for 2 hours.

Apply this to the outer surface of a thoroughly cleaned quartz glass tube (inner diameter 8mm diameter, outer diameter ioamφ, length 30cm).
When placed in a dryer kept at ℃, it gelatinized in 5 minutes.

After being allowed to stand for 1 hour, it was taken out, the above sol solution was again applied to its surface, and it was allowed to stand still in the dryer (70°C) for 2 hours again.

Next, the quartz glass tube was heat-treated at 800° C. for 10 hours in an electric furnace. Then, a heat-generating nichrome wire was inserted into the hollow part of the glass tube, and MgO was filled therein. The nichrome wire was energized and its emissivity was measured at a surface temperature of 500°C. The results are shown in Figure 1.

Further, an Al2O3 plate was used as a base material, and the sol solution was applied thereon, followed by gelation, drying, and heat treatment. When this is heated from the back side with a gas burner, it becomes a similar far-infrared radiator, and the sol solution can be applied to the bottom of a household pan.

According to the method of the present invention, a metal alkoxide is used as a raw material,
Since a strong film can be formed by heat treatment at a relatively low temperature, processing into a far-infrared radiator can be performed easily and inexpensively. Furthermore, there is a high degree of freedom in selecting the base material.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the emissivity of far-infrared emitters obtained in Examples. Figure 1 Class leader (, 11th

Claims (2)

[Claims] (1) A method for producing a far-infrared radiator, which comprises applying a sol solution obtained by hydrolyzing at least one metal alkoxide onto the surface of a base material, gelling it, and performing a heat treatment. (2) The manufacturing method according to item 1 above, wherein the sol solution contains metal oxide powder.