JPH0419181B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a far-infrared ray emitting material, and particularly to a far-infrared ray emitting material that can increase the far-infrared radiation area. [Prior Art] In recent years, ceramic powders have been widely used in various fields, and inorganic binders and hardeners suitable for ceramic powders are used to coat the surfaces of metal ceramics etc. for the purpose of preventing oxidation and improving heat resistance. It is used as a coating material containing a compounding agent, etc., or as an inorganic adhesive for metals, ceramics, etc., and many types of materials are commercially available. On the other hand, ceramics are also known as far-infrared emitting materials, such as zirconia, titania,
Heaters using alumina and other transition element oxide ceramics have already been put into practical use. Conventionally, far-infrared radiation heaters have been made by molding various far-infrared-emitting ceramic powders into arbitrary shapes and sintering them at high temperatures, or by applying far-infrared-emitting ceramic powders to ceramic base materials of arbitrary shapes, etc. Something that is applied like a medicine and then baked to cover it (for example, a method like cloisonné)
Alternatively, it is generally coated by thermal spraying. [Problems to be Solved by the Invention] However, all conventional far-infrared emitting materials require processing such as drying or sintering in a high temperature range, and cannot be said to be industrially advantageous. In addition, in order to further improve the radiation efficiency of far-infrared rays, it is necessary to increase the surface area of the resulting radiator, but so far, far-infrared radiating materials that can effectively increase the surface area of the radiator have not been proposed. It had not been done. [Means for Solving the Problems] In order to solve the above-mentioned conventional problems, the far-infrared emitting material of the present invention comprises: 20 to 90% by weight of far-infrared emitting ceramic powder;
100 parts by weight of a powder raw material made by blending 5 to 20 weight % of monobasic aluminum phosphate powder and 5 to 75 weight % of aggregate with an average particle size of 50 to 800 μm, and a liquid raw material made of water glass and/or alumina sol. , are mixed and kneaded so that the solid content in the liquid raw material is 5 to 25 parts by weight based on 100 parts by weight of the powder raw material, formed into a paste or slurry, coated or molded, and heated at room temperature to A far-infrared emitting material characterized by drying and curing at a temperature of 300°C or less, and a far-infrared emitting ceramic powder of 20 to 90% by weight,
100 parts by weight of a powder raw material made by blending 5-20% by weight of monophosphoric acid aluminum salt powder and 5-75% by weight of aggregate with an average particle size of 50-800 μm, water glass and/or alumina sol, and a diluent. and a liquid raw material, and are mixed and kneaded so that the solid content in the liquid raw material is 5 to 25 parts by weight based on 100 parts by weight of the powdered raw material to form a paste or slurry,
A far-infrared emitting material characterized by being formed by coating or molding and drying and curing at a temperature ranging from room temperature to 300°C or less. The present invention will be explained in detail below. In addition, in this specification, % represents weight % unless otherwise specified. To produce the far-infrared emitting material of the present invention, first, 20-90% of far-infrared-emitting ceramic powder, 5-20% of monobasic aluminum phosphate powder, and 5-75% of aggregate
% is mixed in advance and used as a powder raw material. If the blending ratio of far-infrared emitting ceramic powder is less than 20%, the amount of far-infrared radiation will decrease, and if it exceeds 90%, an efflorescence phenomenon will occur due to a decrease in the amount of monobasic aluminum phosphate added, resulting in a decrease in the amount of aggregate added. Therefore, the surface area increasing effect becomes insufficient. Furthermore, if the blending ratio of the monobasic aluminum phosphate powder is less than 5%, the effect of preventing efflorescence will be insufficient, and if it exceeds 20%, the far-infrared radiating material will become expensive and impractical. Furthermore, if the blending ratio of aggregate is less than 5%, the surface area increasing effect will not be sufficient and the crack prevention effect of the coating layer will not be expected. When the blending ratio of aggregate exceeds 75%, the amount of far-infrared emitting ceramic powder becomes less than 20%, and the amount of far-infrared radiation decreases. Preferably, 40 to 75% of far infrared emitting ceramic powder, 10 to 20% of monobasic aluminum phosphate powder, and 5 to 50% of aggregate are mixed in advance to form a powder raw material. Next, water glass, alumina sol, or a mixed solution of alkali silicate and alumina sol, further adding a diluent as necessary, is prepared as a liquid raw material, and the liquid raw material is added to the powder raw material to obtain the desired amount. Make a viscous paste or slurry. The mixing ratio of powder raw material and liquid raw material is
The solid content in the liquid raw material is 5 to 25 parts by weight per 100 parts by weight.
This is the ratio in parts by weight. If the solid content in the liquid raw material is less than 5 parts by weight relative to 100 parts by weight of the powder raw material, the adhesion strength of the coating layer will be low, and if it exceeds 25 parts by weight,
Produces efflorescence. The paste or slurry prepared in this way is applied to the surface to be coated by brushing or spray painting, or after being poured into a mold and shaped.
The far-infrared emitting material of the present invention is obtained by drying and curing at a low temperature of room temperature to 300° C. or less. In the present invention, the far-infrared emitting ceramic powder may be any commonly used ceramic powder, and is not particularly limited, but examples thereof include powders of zirconia, alumina, titania, and other transition metal oxide ceramics. Among these, those containing 50% by weight or more of transition metal oxides are preferred. The particle size of this far-infrared emitting ceramic powder is smaller than the particle size of the aggregate, and is preferably as fine as possible. As the aluminum monophosphate powder, aluminum triphosphate powder is preferred. As aggregate, coarse particles of ceramics such as sintered aluminum, sintered alumina, and sintered zirconia, silica sand,
Examples include inorganic aggregates such as natural minerals such as mica, and the average particle size thereof is 50 to 800 μm, preferably 200 to 800 μm.
It shall be 600μm. When the average particle size of the aggregate is less than 50 μm, both the surface area increasing effect and crack prevention effect are insufficient, and when it exceeds 800 μm, the adhesion strength of the coating layer becomes weak, and when it is made into a slurry, it precipitates. If the spray method is used, the spray gun nozzle hole may be clogged, which is not preferable. It should be noted that angular shaped aggregate particles are preferred since they have a larger specific surface area than spherical ones. As the water glass, there are various types of commercially available soda water glass, potash water glass, etc., and the type suitable for the purpose is appropriately selected and used. Further, alumina sol is preferably used when it is desired to suppress the efflorescence phenomenon of alkali silicates. Examples of the diluent include colloidal silica, water, alcohol, and the like. In the present invention, in order to adjust the viscosity of the raw material paste or slurry in the manufacturing process, or to improve the water resistance of the obtained far-infrared emitting material, if necessary, kaolin having a layered structure,
Fillers such as clay and talc can also be blended into the raw materials. [Function] Since the far-infrared emitting material of the present invention uses monophosphoric acid aluminum salt, water glass, alumina sol, etc., it can be manufactured by heating and drying at a relatively low temperature of room temperature to 300° C. or less. Furthermore, the monobasic aluminum phosphate increases water resistance, suppresses efflorescence, and brings the coefficient of thermal expansion of the material of the present invention close to that of metal. When the far-infrared emitting material of the present invention is used as a coating layer on a base material, its adhesion is extremely strong. Moreover, by adding aggregate, the outer surface of the far-infrared emitting material of the present invention becomes rough, and its surface area can be increased. Furthermore, by adding aggregate, cracking, chipping, and falling off of the coating layer can be prevented. Incidentally, as shown in FIG. 1, when the far-infrared emitting material of the present invention is used to form a coating layer 1 on a base material 3 such as a heater plate, the aggregate 2 forms the coating layer 1 of the far-infrared emitting material. When the coating layer 4 is formed using a conventional far-infrared emitting material that does not contain aggregate, the rate of increase is greater than when the coating layer 4 is formed using a conventional far-infrared emitting material that does not contain aggregate, as shown in Fig. 2. Compared to that, it reaches about 20-35%. [Examples and Comparative Examples] Below are Examples and Comparative Examples (Production Examples and Test Examples)
The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof. Production examples 1 to 8 Powder raw materials (No. 1 to 8) with the composition shown in Table 1 100
Add liquid raw materials (No. 1 to
8) were added as solid contents in the proportions shown in Table 3 (Nos. 1 to 8) to form a paste or slurry. As shown in Fig. 3, a metal plate 12 containing a heating wire 11 is brush-coated or spray-coated on one side of the surface, and dried and cured at 200°C to form a coating layer 13 with an average coating layer thickness of 0.5 mm. Then, a far-infrared heater 14 was manufactured. Note that 12a is the metal plate 1
This is an electric insulating layer made of mica provided on the surface facing the heating wire 11 of No. 2. The coating layer 13 of the obtained far-infrared heater was firmly adhered to the metal plate. The composition of the far-infrared emitting ceramic powder is as follows. MnO ₂ 60% Fe ₂ O ₃ 20% CuO 10% CoO 10% Test Examples 1 to 9 The raw materials of Production Examples 1 to 8 were mixed in the proportions shown in Test Examples 1 to 8, applied, and dried to obtain a The performance as a far-infrared heater was tested by energizing the heating wire 11 disposed inside the metal plate 12 with the coated layer 13 formed thereon or without the coated layer 13 (Test Example No. 9). . That is, the far-infrared heater 14 produced in Manufacturing Example 1 is coated on the jig 22 of the measuring device, which has a sample mounting jig 22 suspended from the ceiling of a casing 21 with a lid and bottomless structure as shown in FIG. Attach with layer 13 facing downward. Note that at this time, a heat insulating layer 23 is interposed between the jig 22 and the jig 22 . and coating layer 13
A thermocouple 15 was embedded in the center of the tube, and the heating wire 11 was energized to continuously measure the surface temperature.
A current of 1A at 100V AC is passed through the heating wire, and heater 1
When the temperature on the surface of No. 4 reached a constant value (steady state) (about 30 minutes later), the temperature was measured with a thermocouple 15, and this was taken as the surface temperature measurement value. The conditions for this performance test are as follows. Heater metal plate SUS304 Metal plate size 100mm (width) x 100mm (length) x 5mm
(Thickness) Covering layer thickness 0.5mm Insulating layer thickness 50mm Power consumption 100W, single phase 100V (1W/ ^cm2 ) Insulating plate Mica plate heater temperature (temperature on the back side of metal plate when not coated)
350℃ (Test Example No. 9 in Table 3) Temperature measurement thermocouple IC thermocouple Wire diameter 50μm Measurement point Number of measurements at one point at the center of the heater surface 3 times Measurement temperature Room temperature (23±2℃) Measurement result of coating layer surface temperature The average values of are shown in Table 3.

【table】

【table】

【table】

[Table] *4: Corresponds to each number of manufacturing examples in Tables 1 and 2.
*5: When there is no coating layer.
In this test example, the test was conducted under conditions of constant power consumption, so the lower the measured value of the surface temperature of the heater, the more thermal energy was converted to far-infrared radiant energy and emitted. , the performance of the heater is excellent. From Table 3, compared to heater No. 1 (covering layer does not contain aggregate), heaters No. 2 to 8 (covering layer contains aggregate) according to Examples have lower surface temperatures; It is recognized that the energy conversion efficiency is high. That is,
Energy conversion efficiency was improved by increasing the radiation area by adding aggregate. It is also recognized that since the coating layer is formed as granular atomization in spray coating compared to brush coating, the radiation area is increased, the temperature decreases further, and the energy conversion efficiency is improved. [Effect] As detailed above, the far-infrared emitting material of the present invention is produced by kneading an inorganic binder such as an alkali silicate (water glass), alumina sol, or colloidal silica, a monobasic aluminum phosphate salt as a hardening agent, and an aggregate. It is produced by drying and curing, and can be produced by heating and drying at a relatively low temperature of room temperature to 300°C or less. When the far-infrared emitting material of the present invention is used as a coating layer on a base material such as ceramics or metal, its adhesion is extremely strong. Moreover, by adding aggregate, the outer surface of the far-infrared emitting material of the present invention becomes rough, and its surface area can be increased, so far-infrared ray efficiency is greatly improved. Furthermore, by adding aggregate, cracking, chipping, and falling off of the coating layer can be prevented.

[Brief explanation of drawings]

FIG. 1 is a sectional view illustrating a state in which a coating layer of the far-infrared ray emitting material of the present invention is provided, and FIG. 2 is a sectional view illustrating a state in which a coating layer of a conventional far-infrared ray emitting material is provided. Figure 3 is a cross-sectional view showing the far-infrared radiant heater manufactured in Manufacturing Example 1, and Figure 4 is Test Example 1.
FIG. 1, 4, 13...covering layer, 2...aggregate, 3...
Base material, 11... Heating wire, 12... Metal plate, 14...
...far infrared heater, 15... thermocouple.

Claims (1)

[Scope of Claims] 1. Powder made by blending 20 to 90% by weight of far-infrared emitting ceramic powder, 5 to 20% by weight of monobasic aluminum phosphate powder, and 5 to 75% by weight of aggregate with an average particle size of 50 to 800 μm. 100 parts by weight of the powder raw material and a liquid raw material consisting of water glass and/or alumina sol are mixed and kneaded so that the solid content in the liquid raw material is 5 to 25 parts by weight based on 100 parts by weight of the powder raw material. A far-infrared emitting material characterized in that it is formed into a paste or slurry form, coated or molded, and dried and cured at a temperature of room temperature to 300°C or less. 2. The far-infrared emitting material according to claim 1, wherein the aggregate is ceramics or natural minerals. 3 Powder raw material is far infrared emitting ceramic powder 40
~75% by weight, primary aluminum phosphate salt powder 10-20
The far-infrared radiation material according to claim 1 or 2, which is a powder raw material containing 5 to 50% by weight of aggregate with an average particle size of 50 to 800 μm. Material. 4. 100 parts by weight of a powder raw material prepared by blending 20 to 90% by weight of far-infrared emitting ceramic powder, 5 to 20% by weight of monobasic aluminum phosphate powder, and 5 to 75% by weight of aggregate with an average particle size of 50 to 800 μm. , a liquid raw material consisting of water glass and/or alumina sol and a diluent, and are mixed and kneaded so that the solid content in the liquid raw material is 5 to 25 parts by weight based on 100 parts by weight of the powdered raw material, Formed into a paste or slurry form,
A far-infrared emitting material characterized by being coated or molded, dried and cured at room temperature to 300°C or less. 5. The far-infrared radiation material according to claim 4, wherein the diluent is colloidal silica, water, or alcohol.