JPS6340778A - Heat retainer for spraying - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a heat-retaining material for spraying, which is used when performing insulation work on soaking furnaces, heating furnaces, and the like.

(Prior Art) Various types of insulation materials for soaking furnaces and heating furnaces have been known. For example, there is a furnace in which a plate made of lucium silicate or rock wool is attached to the back side of the furnace, and the other heating surface is made of brick or castable refractory material. These devices have the problem of requiring many man-hours to process and install the heat insulating material during construction, and it is difficult to construct complex shapes. Others were lined with refractory or insulating brick. This method also had the drawback of being complicated to construct and having large joints, resulting in large heat loss. Yet another method is to use inorganic fibers or other inorganic materials or mixtures thereof.
It is known to be sprayed in a single layer or in multiple layers to provide insulation. Although this method can solve the problems of linings and joints with complex shapes, it has the disadvantage that it takes a long time to develop the strength required for subsequent spraying of refractories when using conventional sprayed materials. In normal cases, it takes a week or even 10 days to develop strength through curing and drying. This tendency was especially noticeable during the winter. Furthermore, there is a limit to the coating thickness that can be achieved with one spraying, and it is necessary to spray the coating two or three times, which lengthens the construction period and poses a major obstacle to production efficiency.

(Problems to be Solved by the Invention) This invention aims to obtain a heat insulating material for spraying that is easy to install, requires a short curing time to develop the required hardness, and has high heat insulation properties. It is something to do.

(Means for solving the problem) This invention uses inorganic fiber as the main material, and CaO-A
, f'203-based hydraulic aluminate compound (hereinafter referred to as rcA
It is a thermal insulation material for spraying, characterized by adding 10 to 50% by weight of a mixture of 1:1/3 to 3 of calcium sulfoaluminate compound (hereinafter referred to as rsAJ) and calcium sulfoaluminate compound (hereinafter referred to as rsAJ). be. This invention will be explained below.

Conventional lightweight spraying, which uses fibrous material as the main material and adds a small amount of hydraulic binding material, is a method of spraying that minimizes the amount of dust generated during the work. In order to achieve the target low bulk specific gravity and stable adhesion, it is necessary to balance the appropriate raw material delivery rate, blower pressure, and spray water amount, and the operator must:
The usual method is to carry out construction while making these adjustments.

In such cases, for the purpose mentioned above, the amount of water required for the final cured product, that is, the amount of water sprayed usually ends up containing a large amount of water (surplus water) than the amount of water required for curing the binder in the material. Met. However, spraying this excess water not only delays the hardening of the body, but also increases the water content of the body itself, so when spraying, especially on ceilings, etc., spraying should be done during construction or immediately after completion. The adhesion force cannot withstand it, and those skilled in the art are forced to carry out inefficient work that requires a lot of man-hours, such as avoiding thick spraying all at once and performing the work in several parts to ensure safety. was there. In addition, even after spraying is completed, this surplus water remains in the cured product for a long time, so the strength of the cured product is significantly lower than that when dry. When this is done, there is a problem in that it takes an extremely long drying period to develop the required pressure-resistant hardness. Therefore, the present invention aims to accelerate the curing of CA while at the same time preventing the generation of such surplus water.

According to the inventor's experiments, the curing time is long if only a CA-based hydraulic aluminate compound is added to the inorganic fiber.
Strength and hardness were also low. Furthermore, even when only the SA used in the present invention was added to the inorganic fibers, the curing time was long and the strength and hardness were similarly low. However, depending on what the inventor carried out, the ratio of CA and SA was 1/3 to 3.
It has been found that when a constant proportion of 10 to 50% of the total amount is blended, a heat insulating material that is light in weight and has high strength with a short curing time can be obtained.

The material for spraying of the present invention is made by using inorganic fibers such as ceramic fibers and rock wool fibers as the main raw materials, and blending the above-mentioned CA and SA in the ratio of 1/3 to 3 to the main raw materials. 10 to 50% by weight of the total amount.

Regarding the above CA/SA, if CA/SA is less than 1/3, it will not be cured, and if it exceeds 3, curing will be delayed. The ratio of CA/SA is 1/3 to 3 as mentioned above.
Adding 10 to 50% by weight of the total amount,
If this is less than 10%, curing will be poor;
If the spraying exceeds this value, the bulk density of the body increases, which not only impairs the heat insulation properties, but in both cases, the curing time is short, making it impossible to obtain a lightweight yet high-strength heat insulating material. These raw materials are packaged and traded in a dry state, but when used, they are usually sprayed onto the furnace wall using a device while adding approximately 100 to 140% water.

Although the effect of the spraying heat insulating material of the present invention is not necessarily clear, it is speculated as follows.

In other words, SA is known as a static crushing agent for concrete, etc.
As is already well known, a large amount of water is absorbed and reacted to rapidly form needle-like crystals of ethrin guide (BCa group A 1203 3 Ca
It generates S O4' 32 H20) and at the same time gives an expanding force to the surrounding area, but the same effect occurs immediately after the main spraying is performed inside the body, and the spraying makes the body lighter and denser. At the same time, a characteristic curing accelerating effect due to the combination of CA and SA, which was discovered by the present inventor, is added.
It is believed that these two effects made the present invention possible.

The present invention will be further explained with reference to Examples below.

Examples (1 to 4) and Comparative Examples (1 to 6) The raw materials used and the blending ratio of raw materials were as described in the table. Among these, ceramic fibers include Ibiwool (product name of IBIDEN Co., Ltd.), rock wool includes Rock Fine Fiber (product name of Asahi Asbestos Co., Ltd.), CaO-A, I? 2 o, The hydraulic aluminate compound is Asagai Alumina Cemen No. 81 (trade name of Asahi Glass Co., Ltd.), and the calcium sulfoaluminate compound is:
Denka CSA#20 (trade name of Denki Kagaku Kogyo Co., Ltd.) was used. Add 100 to 140% water by weight to these dry mixtures.
In addition, the usual method of spraying is to spray 100m thick on a vertical wall using a machine, leave it for 10 hours, and then cut it out from the wall. Thereafter, after the required curing time shown in the photo had elapsed, it was used as a specimen. The bending strength of this material was measured according to JIS A9504 (rock wool insulation material).

Moreover, heat resistance was measured according to JIS A9510 (Rusium silicate heat insulating material).

The results were as shown in the table.

As is clear from the results in the table, the invention according to the present application is
Although both are lightweight, curing time is quick, and the degree of curing (
It can be seen that it has high hardness) and high heat resistance.

In experiments conducted by the present inventors, the required hardness to withstand the spraying of refractories after spraying the amorphous heat insulating material was 1300 g.
In view of the above, and from the standpoint of improving the efficiency of the construction period, it has been determined that it is desirable for the curing time to be within 24 hours. In this example, satisfactory results were obtained in all of these respects.

On the other hand, in the comparative example, the hardness was low and the curing time was long. Furthermore, looking at the strength, the present example shows high bending strength, while the comparative example has the same specific gravity but low bending strength.

(Effects of the Invention) According to the present invention described above, a lightweight and high-strength spray heat insulating material can be obtained. Furthermore, this spray heat insulating material is easy to apply and takes a short curing time, greatly contributing to shortening the construction period. In addition, when using this spray heat insulating material, the shape retention is good, and peeling and falling off during spraying can be avoided.

Therefore, it is expected that this sprayed heat insulating material will be widely used as a multilayer or single layer heat insulating material for soaking furnaces, heating furnaces, and the like.

Claims (1)

[Scope of Claims] 10 to 50 inorganic fibers containing inorganic fiber as the main material and a mixture of a CaO-Al_2O_3-based hydraulic aluminate compound and a calcium sulfoaluminate compound in a ratio of 1:1/3 to 3. A thermal insulation material for spraying characterized by adding % by weight.