JPH0460940B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a block body with excellent fire resistance and heat insulation properties used in various furnaces and other heating devices. [Prior Art] Recently, from the viewpoint of energy saving, heat insulating materials have been widely used in various heating devices including various furnaces. However, while there are many insulation materials that can be used at relatively low temperatures, there are limitations when it comes to fire-resistant insulation materials that can be used at high temperatures. Conventional fireproof insulation materials have a limit to their thermal conductivity, so if they are tightly packed, the thermal conductivity increases, so efforts are being made to increase the number of independent sealed pores inside fireproof insulation materials. ing. However, a refractory heat insulator with many pores has a low strength, and its uses are inevitably limited. For example, insulation materials using asbestos or diatomaceous earth have excellent insulation properties, but have poor heat resistance and low strength. Asbestos is also carcinogenic. On the other hand, although a heat insulating material using hollow alumina has excellent heat resistance, it is not sufficient in terms of heat insulation. Furthermore, ceramic fibers and alumina fibers, which have recently begun to attract attention, are still insufficient in terms of thermal conductivity. [Problem to be solved by the invention] As described above, the thermal conductivity and strength of fire-resistant insulation materials have contradictory properties, and fire-resistant insulation materials that have high strength as fire-resistant insulation materials but also have very low thermal conductivity. is desired. The thermal conductivity of the titanium compound fibers, including the potassium titanate fibers used in the present invention, is extremely low compared to other insulation materials, especially inorganic fibers. Even if the strength is improved, the thermal conductivity can be kept low. However, titanium compound fibers are extremely difficult to sinter, and have the disadvantage that sufficient strength cannot be obtained by sintering, especially when used to make fireproof heat insulators with high porosity as in the present invention. . [Structure of the Invention] The main insulator of the block body of the present invention is alkali metal titanate fibers such as potassium titanate fibers, alkaline earth metal titanate fibers such as barium titanate fibers, and other titanate fibers. One or more types selected from metal fibers, titanium compound fibers such as anatase type or rutile type titania fibers, and hydrate fibers thereof.
In particular, it is preferable that the fiber contains potassium titanate fiber or titania fiber. It is also possible to mix and use other inorganic fibers with these various titanium compound fibers. Alumina sol is added to this fiber as a binder. It has been found that alumina sol is the most suitable binder for this purpose, and is most suitable as a binder for titanium compound fibers that are difficult to sinter.
On the other hand, if a silicic acid binder such as silica sol or sodium silicate is used, it will react with the titanium compound fiber during firing, resulting in large shrinkage and deformation of the block, resulting in hexagonal cracks on the surface, making it unusable. Further, phosphoric acid binders also cause cracks during drying after molding, which is also undesirable. The amount of alumina sol added is
The amount is 5 to 30 parts by weight per 100 parts by weight. If the amount added is less than 5 parts by weight, the engagement effect will be poor, and if it exceeds 30 parts by weight, the thermal conductivity of alumina will be high.
The thermal conductivity of the block body increases, which is not preferable. If alumina sol alone is used as a binder, if the strength of the base after molding and drying is poor, corners will be chipped during handling, which is undesirable. Therefore, auxiliary binders such as Sansal extract, pulp waste liquid, CMC, and other lignin salts are added to 100 parts by weight of titanium compound fibers. It is also possible to add 0.05 to 2.0 parts by weight.
If the amount added is less than 0.05 parts by weight, the addition effect will be poor, and if it exceeds 2 parts by weight, cracks will occur during drying. In addition, titanium compound fibers are fine powders, which are insufficient to prevent lamination during molding.
In order to reduce the frictional resistance with the mold, 0.05 to 2.0 parts by weight of an anti-friction agent such as aluminum stearate or other stearates can be added to 100 parts by weight of the titanium compound fiber.
If the amount added is less than 0.05 parts by weight, the effect of the addition will be poor, and if it exceeds 2 parts by weight, the strength after drying will decrease, which is not preferable. The above-mentioned raw materials, ie, titanium compound fibers, alumina sol, an auxiliary binder and a lubricant if necessary, are thoroughly mixed, water is added in an amount of 10 to 45% by weight, and the mixture is kneaded and then molded. After that, after drying
By firing at a temperature of 950 to 1150°C, a fireproof and insulating block body is obtained. This combination prevents the lamination that is characteristic of fine powder, allows the fibers to intertwine well, and combines the titanium compound, which is said to be difficult to sinter, with the sintering effect of the alumina sol binder, to create high strength without cracking or deformation. It is possible to obtain a sintered body having the following properties. [Effects of the Invention] As described above, since the fireproof insulation block of the present invention is manufactured by bonding titanium compound fibers such as potassium titanate fibers with alumina sol, it is lightweight, has high strength, and has low thermal conductivity. Because it is extremely low, conventional products may not have sufficient insulation effect or lack strength and if used for a long time,
It can be very effective when used in areas where cracks or gaps have formed, causing the entire structure to become loose and shortening the life of a heating furnace or the like. [Example] Examples 1 to 2, Comparative Examples 1 to 2 After kneading and molding the formulation shown in Table 1, Example 1
The sample was heated at 1000℃ for 20 hours, and the sample in Example 2 was heated at 1100℃ for 10 hours.
Samples of Comparative Examples 1 and 2 were baked at 1200°C and 1400°C for 72 hours, respectively. Table 1 shows the physical properties of the obtained sample. The samples of Examples 1 and 2 both have very low thermal conductivities, and their values hardly change at low or high temperatures, and their strength is relatively high, with only slight shrinkage even when reheated. On the other hand, although the sample of Comparative Example 2 is superior in strength and reheating shrinkage rate, its thermal conductivity is much higher, and Examples 1 and 2 are far superior in terms of thermal insulation properties. ing. On the other hand, the sample of Comparative Example 1 has relatively low thermal conductivity but weak strength. As described above, the fireproof heat insulating block according to the present invention satisfies both properties of thermal conductivity and strength at the same time.

[Table] Example 3 The ceiling of a silicone electric furnace with an inner wall of 265 x 205 x 230 mm was divided into two parts, one was used as Comparative Example 1, the other was used as Examples 1 and 2, and Comparative Example 2, respectively, and the inside was heated to 1000°C. The temperature of the outer surface was measured when a steady state was reached. At this time, the walls other than the ceiling were made of the material of Comparative Example 1, and the thickness of each wall was 55 mm. The results showed that while Comparative Example 1 was at 223°C, Comparative Example 2 was at 310°C, Example 1 was at 145°C, and Example 2 was at 150°C. The results were outstanding, demonstrating the excellence of the present invention.

Claims (1)

[Claims] 1. One or more types of titanium compound fibers such as alkali metal titanate fibers, alkaline earth metal titanate fibers, and titania fibers are bonded together using alumina sol. Features a fireproof insulation block body. 2. The fireproof insulation block body according to claim 1, wherein the titanium compound fiber is potassium titanate fiber. 3. The fireproof insulation block body according to claim 1, wherein the titanium compound fiber is titania fiber.