JPH034510B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a heat-retaining material for spraying, which is used to insulate 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 one in which a plate made of calcium silicate, rock wool, or the like is attached to the back side of the furnace, and the other heating surface is made of brick or castable refractory material. Problems with these products include the fact that processing and installing the insulation material takes many man-hours 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 a large number of joints, resulting in large heat loss. As a further alternative, it is known to spray inorganic fibers or other inorganic material areas with mixtures thereof, either 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, the disadvantage of conventional sprayed materials is that it takes a long time to develop the strength necessary for spraying refractories after spraying. In the normal case,
It took a week or even 10 days to develop strength due to 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 process, 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) The present invention aims to obtain a spray-on heat insulating material 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,
A CaO-Al ₂ O ₃ -based hydraulic aluminate compound (hereinafter referred to as "CA") and a calcium sulfoaluminate compound (hereinafter referred to as "SA") were mixed in a 1:1 ratio.
This is a thermal insulation material for spraying, characterized in that it contains 10 to 50% by weight of a mixture of 3 to 3.
This invention will be explained below. When applying conventional lightweight sprayed materials, which are mainly made of fibrous material with a small amount of hydraulic binding material, using a regular spraying machine, it is important to minimize the amount of dust generated during the spraying process. In order to obtain a sprayed object with the target low bulk specific gravity and stable adhesion, it is necessary to balance the appropriate raw material delivery amount, blower pressure, and spray water amount, and the operator must adjust these while performing construction. The usual method is to do so. In such cases, it is normal for the final cured product to contain a large amount of water (surplus water), which is greater than the amount of water required for curing the binder in the sprayed material for the above purpose. It was hot. However, this excess water not only delays the hardening of the sprayed body but also increases the water content of the sprayed body itself, so especially when constructing ceilings etc.
During spraying or immediately after spraying is completed, the adhesion cannot withstand the strength, and those skilled in the art should avoid spraying thickly at once, and carry out the work in several parts to ensure safety.
There was an unavoidable need to perform inefficient work that required a lot of man-hours. In addition, even after spraying is completed, this excess water remains in the hardened material for a long time, so
The strength of the cured product is also significantly lower than that when dried, and when sprayed refractories and the like are subsequently applied, there is a problem in that a significantly longer drying period is required 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 experiments conducted by the present inventors, simply adding a CA-based hydraulic aluminate compound to inorganic fibers resulted in long curing times and low strength and hardness. 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, according to what the inventor has carried out, it has been found that by blending 10 to 50% of the total amount of CA and SA at a constant ratio of 1/3 to 3, the curing time is short and the product is lightweight. It has been found that a high strength insulating material can be obtained. The spraying material of the present invention uses inorganic fibers such as ceramic fibers and rock wool fibers as main raw materials.
For this main raw material, mix the above CA and SA at 1:1/3.
-3 is added in an amount of 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. CA/SA
The ratio of 1/3 to 3 as mentioned above is added in an amount of 10 to 50% by weight of the total amount, but if it is less than 10%, curing will be poor, and if it exceeds 50%, the bulk of the sprayed object will increase. Not only does the density increase, which impairs the insulation properties, but in both cases the curing time is short, making it impossible to obtain a lightweight yet high-strength insulation material. These raw materials are packaged and traded in dry form,
In use, approximately 100 to 140% water is added to the mixture and sprayed onto the furnace wall using an ordinary spraying device. Although the effect of the spray heat insulating material of the present invention is not necessarily clear, it is speculated as follows. In other words, it is known as a static crushing agent for concrete, etc.
As is already well known, SA absorbs a large amount of water and rapidly reacts with the ethrin guide (3Ca.
This method generates Al ₂ O ₃・3CaSO ₄・32H ₂ O) and at the same time gives an expanding force to the surrounding area.The same effect is carried out in the main sprayed body immediately after spraying, making the sprayed body lightweight and At the same time as densification, a characteristic curing accelerating effect is added due to the combination of CA and SA, which the present inventor happened to discover, and 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 raw material blending ratio were as described in the table. Among these, ceramic fibers include Ibiwool (product name of IBIDEN Co., Ltd.), rockwool is Rockfire Infiber (product name of Asahi Asbestos Co., Ltd.), and CaO-
The Al ₂ O ₃ hydraulic aluminate compound is Asahi Alumina Cement No. 1 (trade name of Asahi Glass Co., Ltd.), and the calcium sulfur aluminate compound is Denka.
CSA#20 (trade name of Denki Kagaku Kogyo Co., Ltd.) was used.
Adding 100 to 140% by weight of water to these dry mixtures, the mixture was sprayed onto a vertical wall to a thickness of 100 mm using a conventional spraying machine, and then cut out from the wall after standing for 10 hours. Thereafter, after the required curing time shown in the table had elapsed, it was used as a specimen. The bending strength of this material was measured according to JIS A9504 (Rock wool insulation material). In addition, regarding heat resistance, JIS
Measured according to A9510 (calcium silicate insulation material). The results were as shown in the table.

【table】

[Table] As is clear from the results in the table, the products according to the present invention have a quick curing time, high curing degree (hardness), and high heat resistance despite being lightweight. Ru. In experiments conducted by the inventors, the required hardness to withstand spraying of refractories after spraying of amorphous heat insulators is as follows:
Considering the hardness of 1300g or more, and the efficiency of the construction period,
It has been determined that the curing time is preferably 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. Moreover, 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, it has good shape retention and can eliminate peeling and falling off during spraying. for that,
This spray heat insulating material is expected to be widely used as a multi-layer or single-layer heat insulating material for soaking furnaces, heating furnaces, etc.

Claims (1)

[Claims] 1 Main material is inorganic fiber, and CaO−Al ₂ O ₃
A thermal insulation material for spraying, characterized in that it is made by mixing 10 to 50% by weight of a mixture of a hydraulic aluminate compound and a calcium sulfoaluminate compound in a ratio of 1:1/3 to 3.