JP2928126B2 - FIBER MOLDED BODY AND COATING METHOD THEREOF - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fibrous formed body used for lining in a furnace and a method for coating the fibrous formed body.

[0002]

2. Description of the Related Art Conventionally, refractory bricks, heat insulating bricks, ceramic fibers, and the like have been used to insulate a heat treatment furnace. Among these materials, ceramic fibers have high heat insulation and low heat capacity, so the furnace has good thermal response,
A furnace that can be easily operated can be provided.

However, ceramic fibers have various problems due to their high porosity. For example, inside a furnace into which a specific gas to be reacted with an object to be baked is heated under an atmosphere, or a gas introduced as a gas or a gas generated as a result of a reaction in the furnace has a relatively high boiling point and a relatively high melting point. When the temperature of the refractory material is reduced by entering the pores of the lining material, condensation (condensation) may cause the lining material and the furnace shell to corrode, or solidify to fill the voids. There was a drawback of losing.

Typical examples of the use of the above introduced gas include a silicon nitride manufacturing furnace which is a non-oxide ceramic, a titanium carbide coating, a boron carbide coating on a cutting tool by a vapor deposition method, and a carbon product. There is a reaction furnace for performing silicon carbide coating and the like. Recently, a technique for producing a high silicon steel sheet by impregnating iron with silicon in a gas phase has also been developed.

In the above reactor, for example, ammonia (silicon nitride), silicon tetrachloride (silicon nitride, silicon carbide, silicon),
Chloromethylsilane (silicon nitride, silicon), methane (silicon carbide, titanium carbide, boron carbide), propane (silicon carbide, titanium carbide, boron carbide), hydrogen (carrier) and the like are used.

[0006] In these, coating components which are not adhered to the object to be treated, such as silicon nitride, silicon, titanium carbide, etc., due to the reaction of unintroduced introduced gases or gases, thermal decomposition, or reaction with the object to be treated, substitution reaction, etc. Hydrogen chloride, iron chloride, etc. are generated in the furnace atmosphere, and some of them are discharged out of the furnace through the exhaust system, but some of them stick to the surface of the lining material or enter the voids of the lining material Or the above-mentioned problem.

[0007] From the above, in a heating furnace or a reaction furnace heated in an atmosphere, a hard lining material having a small porosity is generally used even if heat insulation is sacrificed, but a high porosity is used. Even if a lining material is used, it is possible to use a lining material having a high porosity without sacrificing heat insulation, as long as gas intrusion can be prevented from the surface thereof.

The lining material having a high porosity as described above,
That is, there are the following surface treatment techniques for ceramic fibers and fiber boards.

Coating the surface of the lining material with a far-infrared radiating material (Japanese Patent Laid-Open No. 213371/1990)
7, Japanese Patent Application Laid-Open No. Hei 2-302588, Japanese Unexamined Patent Application Publication No. 2-302588, and a method of applying an alkali coating for the purpose of preventing the lining material from being loosened (wobbled). for those coated graphite powder (JP-a-3-87593, JP-known technique 3), FeO as for thermal radiation, that coating the Cr ₂ O ₃ component (JP-a-3-229829, JP-
Known technology 4), using a coating material containing boric acid, SiO ₂ and an organic resin to prevent shrinkage and provide wind resistance (Japanese Patent Application Laid-Open No. 60-21886, known technology 5), lining a refractory slurry By forming a hard surface layer by immersing the surface of the material
No. 38181, known technology 6), lining material (fiber blanket) using alumina sol and silica sol
(See Japanese Utility Model Application Laid-Open No. Sho 62-157220, known technology 7).

[0010]

However, according to the above-mentioned known technique, a hard layer is formed on the surface of the lining material, but it is difficult to shield the above-mentioned gas. Among the most promising ones are known technology 2 and known technology 5, but when a liquid material is applied to the surface of a ceramic fiber, the fibers are bundled by a certain small range due to the surface tension of the liquid sucked by the capillary phenomenon. It is in a state where a large number of hardened fibers are scattered like islands.

In the case where the bundled fibers are formed in this manner, a certain effect can be expected with respect to the falling off (wobbles) due to the dispersion of the fibers and the wind resistance due to the solidified fiber ends. Even if it is obtained, gas cannot be shielded because a uniform shielding layer is not formed on the surface of the lining material.

When the above-mentioned coating material is applied to the surface of a fibrous molded product, cracking or peeling of the coating layer occurs after heating as a phenomenon that appears remarkably. These are caused by differences in expansion and contraction rates between the lining material and the coating layer due to heating and cooling.

The inventors of the present invention have developed a ceramic coating material of "Tight Ace" or "N-TAC" manufactured by the company (Shinagawa White Brick Co., Ltd.) or "Pyro Bond Ace" used for bonding iron and a fiber module. Due to their high adhesiveness and confidentiality when heated, they were thinly applied to the surface of the fiber molded body and heated. As a result, even with these materials, cracks occurred, and exfoliation occurred in severe portions. This was determined to be due to the high water absorption of the fiber molded body, and the present invention was reached by repeating various tests.

That is, in the present invention, when the purpose of gas shutoff is intended, the coating layer is in a glass state, or based on a basic idea that it is best that the coating layer is molten at an operating temperature and has no pores. A fibrous molded article and its coating, which reliably prevent gas intrusion even if a lining material (fibrous molded article) having high porosity and good heat insulation performance is used, without causing cracking or peeling of the coating layer. The aim is to provide a method.

[0015]

As means for solving the problems with the prior art SUMMARY OF THE INVENTION The present invention provides a molded article to be molded by combining the organic and inorganic binder fiber material
In the ceramic fiber blanket binder
Consists of a single layer or multiple layers impregnated and compression bonded
Oyo organic fibrous molded body, wherein a gas is subjected to coating of hard nature penetrates at least one surface perpendicular to the furnace lining direction of the molded body, and the fiber material
Of molded body formed by bonding with inorganic binder
Include a binder in the ceramic fiber blanket.
A treatment is performed so that an organic resin and an inorganic binder which is a component similar to the molded body by heating are present on at least one surface of the molded body formed of a single layer or a plurality of layers which are immersed and compression-bonded and are perpendicular to the furnace lining direction. A method for coating a fibrous formed body, characterized in that a coating material is applied to one surface thereof and heat treatment is performed after coating to form a coating layer having a property of preventing gas from entering .

[0016]

According to the above construction, the organic resin and the inorganic binder which becomes similar to the fibrous molded body by firing are present in the vicinity of the surface of the fibrous molded body to be coated. Water repellency is imparted to the body, and the liquid component contained in the coating material applied to the fibrous molded body remains on the surface of the fibrous molded body, and a film equivalent to that applied to the surface of the hard material is formed. .

The inorganic binder binding the fibrous material changes into an inorganic material during firing, and in the process, contributes to some extent to the improvement of the adhesiveness between the fibrous formed body and the coating material.

In the case where only the inorganic binder is used, the water repellency becomes insufficient, and the liquid component necessary for curing contained in the coating material after application is sucked into the fibrous molded body from the surface to form the coating. Changes in the components, and the desired performance cannot be exhibited. Conversely, when only organic resin is used, although the situation after application is good, peeling or cracking may be observed after the firing treatment. This is because the organic resin is thermally decomposed and dissipated in the early stage of firing, then the temperature rises, and when the coating material starts melting, a part of the coating material is sucked into the fibrous molded body by capillary action and remains at the surface. Lower. In this regard, in the case of the present invention, the coexistence of the organic resin and the inorganic binder causes the highly reactive binder component to react with the coating component, increasing the viscosity of the melt, stopping the flow, and stopping the flow to form the fibrous molded article. Satisfactorily adheres to the vicinity of the surface to achieve the intended purpose. As a result, heating and cooling can be achieved by using the furnace after
The ceramic fiber blanket
The joint expands and contracts to open the joint, and gas invades from the gap.
And penetrate the ceramic fiber blanket
Is prevented.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

The fibrous molded body 1 is formed by impregnating a single or plural blanket-shaped ceramic fibers with a binder aqueous solution containing an organic resin and an inorganic binder, and pressing the ceramic fibers to a predetermined thickness. It is manufactured by drying afterwards.

The amount of the organic resin added is 1 to 20% by weight based on the aqueous binder solution, and the amount of the inorganic resin is 2 to 20% by weight.
wt%. It is preferable that the dried fibrous molded body contains an organic resin and an inorganic binder in an amount of 0.5 wt% or more each.

The shape retention and binder retention until the binder is hardened by drying after molding to a predetermined thickness largely depends on the concentration of the binder. Therefore, the viscosity of the aqueous binder solution should be 0.1 to 10 CP. Is preferred. Further, a means for fixing the inorganic binder to the fibrous formed body by adding a sulfuric acid band and polyaluminum chloride may be used.

As another method for producing the fibrous molded body 1, a crushed ceramic fiber and an organic and inorganic binder are put into water, mixed with each other, and then transferred to a molding frame capable of removing excess moisture by suction. And can be manufactured by a vacuum forming method.

In the above production, as the organic resin, a vinyl acetate resin emulsion, a polyacrylate emulsion, hydroxymethyl cellulose, carboxymethyl cellulose (CMC), hydroxyethyl cellulose, polyvinyl alcohol and the like can be used.

As the inorganic binder, silica sol,
Alumina sol, zirconia sol, sodium aluminate, sodium silicate, zirconium acetate, ethyl silicate and the like can be used.

Of the above organic resins, it is preferable to use a vinyl acetate resin (emulsion), hydroxymethyl cellulose, CMC, or polyvinyl alcohol from the viewpoints of cost and odor generation during heating. It is about 0.01 to 5%, and more preferably about 0.1 to 3%. In the case of an inorganic binder, silica sol is the easiest to use in an alumina-silica fibrous molded article having an overwhelmingly large production amount, and its blending amount is 1-2.
It is about 0%. Further, a means for fixing an inorganic binder to which aluminum sulfate, polyaluminum chloride, or various polymer-based coagulants are added in the fibrous formed body 1 may be used.

Fibrous molded products are classified into calcined products and unbaked products. Usually, calcined products are used because of their strength and to avoid smoke during use. However, when calcined, the organic resin decomposes. Since the water repellency becomes insufficient and the coating material is apt to crack, an unfired product is used in the practice of the present invention.

A general-purpose fibrous molded article (fiber board) generally called 1300 FB or 1260 FB is:
Ceramic fiber having a chemical composition of about 50% alumina and 50% silica (STD manufactured by Shinagawa Shiro Brick Co., Ltd.)
Is used as raw cotton.

On the other hand, in the case of a fibrous formed body (fiber board) for high temperature, for example, called 1600 FB, alumina 7
A crystalline alumina fiber having a composition of 2 to 97% is used as raw cotton. For high-temperature use, products obtained by blending fiber and high-alumina-based refractory raw material powder (for example, BD1600 manufactured by Denki Kagaku Kogyo Co., Ltd.
D1600).

When producing a fibrous molded article by the vacuum suction method, the content of the organic resin and the inorganic binder in the fibrous molded article is preferably 0.5 wt% or more. However, if the binder concentration of the aqueous solution is too high, suction becomes difficult, and the workability of vacuum forming is inferior. In this case, for example, an aqueous solution of 1 to 8% by weight of an organic resin and 3 to 30% by weight of an inorganic binder is applied to the surface of the fibrous formed body, which is to be a coating surface of the coating material after completion of forming and drying, by a spray gun or the like.
Take measures such as spraying at a rate of 05 to 0.3 ^l / m ² .

The coating material used in the present invention is:
Some at use temperature is made dense tissue softened state, and are not having a property of gas is less likely to penetrate the fibers
The surface 1a perpendicular to the lining direction of the
It will be Examples of the refractory aggregate powder used for such a coating material include silica stone, rock stone, chamotte, mullite, and alumina. The particle size of the refractory aggregate powder is 100 μm or less, preferably 44 μm or less in view of workability of the coating material. As the glass material powder, frit, borosilicate glass, lead-containing glass, mica and the like can be used. Also in this case, the particle size of the glass material powder is preferably 44 μm or less from the viewpoint of uniform dispersion and workability of the coating material.

The mixing ratio (wt) of the refractory aggregate powder and the glass material powder is 90 to 60% for the refractory aggregate powder and 10 to 40% for the glass material powder. Here, if the glass powder content is less than 10%, a dense structure in which gas does not easily enter cannot be obtained, and if it exceeds 40%, heat resistance cannot be obtained.

On the other hand, refractory aggregate powder and glass powder 100
The following examples are given as the amount of the binder to be added to the wt part. (A) Addition of 10 to 20 parts A complex alkoxide partially hydrolyzed sol composed of at least one selected from Si alkoxide, Ti alkoxide, Al alkoxide, and Zr alkoxide is used.

An alcohol such as ethyl alcohol or isopropyl alcohol is added to adjust the viscosity as desired in view of workability of the coating material.

This binder has excellent features for use as an inorganic heat-resistant adhesive. (B) 10 to 30 wt parts of the following materials are added as a binder: water-soluble alkali borosilicate 35 to 60 wt% silicon polyphosphate 10 to 25 wt% alkali silicate fluoride 10 to 45 wt% Add water.

This binder has excellent features for use as an inorganic adhesive used for mounting a ceramic fiber module.

As a means for producing the coating material used in the present invention, the above-mentioned components can be produced to a desired viscosity (5 to 60 P) by kneading them with an ordinary mixer.

As for the application of the coating material, as shown in FIG. 2, the surface of the fibrous molded body 1 on the inner surface side of the furnace is sprayed by a spray gun, or applied by a trowel, a roller, a brush or the like, and dried. Gas enters the surface of the fibrous formed body 1 by heat treatment at a temperature of 1000 to 1200 ° C.
A coating with difficult properties is obtained.

Next, a specific embodiment will be described. Fibrous Molded Articles of Example 1 and Comparative Example 2 Fiber: fiber 100 (wt) of about 50% Al ₂ O _{3 and} 50% SiO ₂ B. Organic resin; methyl cellulose 0.2 C.I. Inorganic binder; silica sol SiO ₂ 6 D. Water 4000 The crushed fiber A was put into the aqueous solution consisting of B, C, and D, mixed, and then the excess water was removed by suction, vacuum formed, and dried at 110 ° C.

In Example 1, the aqueous solution consisting of silica sol (containing 20% of SiO ₂ ) 10% alumina sol (containing 10% of Al ₂ O ₃ ) 5% vinyl acetate 4% water 81% was used as a pretreatment for coating. The molded body was sprayed onto the inner surface of the furnace at a rate of 0.1 ^l / m ² by a spray gun.

In Comparative Example 2, as a pretreatment for coating, a 4% aqueous solution of vinyl acetate was sprayed onto the inner surface of the fibrous formed body at a rate of 0.09 ^l / m ^{2 using} a spray gun. Fibrous molded article of Example 2 Fiber: Al ₂ O ₃ 75% crystalline fiber 100 (wt) Organic resin; methyl cellulose 0.2 C.I. Inorganic binder; silica sol SiO ₂ 6 D. Flocculant; polyaluminum chloride 0.001 Water 4000 The crushed fiber A was put into the aqueous solution consisting of B, C, D, and E, and mixed. After that, excess water was removed by suction, vacuum formed, and dried at 110 ° C. In the above case, the amount of the inorganic binder fixed in the fibrous molded body is increased because the coagulant is used.

As a pretreatment for coating, an aqueous solution was sprayed in the same manner as in Example 1. Fibrous Molded Product of Example 3 _Two 25 mm thick crystalline fiber blankets of 72% Al ₂ O ₃ were stacked on top of each other, and 10 wt% of silica sol containing 20 wt% of SiO _{2 and} 5 wt% of alumina sol containing 10 wt% of Al ₂ O ₃ , 4% by weight of vinyl acetate resin emulsion,
It was immersed in an aqueous solution having a viscosity of 6.5 cp consisting of 81 wt% of water and squeezed by a squeezing roller to a thickness of 30 mm.
Dried at ° C. Fibrous Molded Article of Example 4 _Two 25 mm thick Al ₂ O ₃ 80% crystalline fiber blankets were stacked and immersed in the same aqueous solution as in Example 3,
It was pressed to a thickness of 30 mm by a pressing roller and dried at 110 ° C. Fibrous Molded Article of Comparative Example 1 The fibrous molded article of Example 4 was fired at 1000 ° C. for 1 hour.

The coating material (coating material viscosity 40 P) used in the examples was alumina powder 75 wt% mica powder 25 alkali borosilicate aqueous solution (* 1) 67 alkali phosphate and alkali silicofluoride (* 2) 7 * 1 Mizusawa Chemical "Mizukanex M / 100" * 2 Same as above "Mizukanex M / 300"

[0044]

[Table 1] As is evident from the above test results, in the present invention, when the surface of Examples 1 and 2 (both unfired) was sprayed with an organic-plus-inorganic binder and surface-treated, and then the above-mentioned coating material was applied, The surface condition after firing was good. When the coating material was directly applied to the surfaces of Example 3 and Example 4 (both were not fired), the surface condition after firing was extremely good.

On the other hand, when the coating material was applied directly on the surface of Comparative Example 1 (fired), cracks occurred on the entire coated surface, and the organic binder was sprayed on the surface of Comparative Example 2 (unfired). When the coating material was applied after the surface treatment, cracks occurred on a part of the coated surface.

Therefore, when the coating according to the present invention is applied to a heat insulating board, it is effective to apply the heat insulating board to the innermost layer of the furnace lining as a gas shielding plate.

[0047]

As described above, according to the present invention, when a fibrous formed body is used as a lining material of a furnace into which various gases are introduced to adjust the atmosphere in the furnace, the lining material is It is possible to suppress gas intrusion, keep the overall heat capacity small, and at the same time keep the heat insulation, and thereby configure a furnace with good responsiveness and easy operation. In addition, the coating material is applied to the lining material of the fibrous molded body that has a small amount of binder for fiber bonding, after spraying the organic and inorganic binder on the surface to be coated, so that the liquid component of the coating material is applied to the fibrous molded body by capillary action. The liquid component necessary for curing the coating material is secured without infiltration, and the original strength of the coating material is developed, and a strong coating layer can be formed. In a lining material with many binders, the binder prevents the liquid component of the coating material from entering, so that the liquid component of the coating material is also secured and a strong coating layer is formed, which causes cracking and peeling. Can be prevented and the furnace is heated after the furnace is built.
・ Fibrous molded body expands and contracts due to repeated cooling
The joints open and the gas enters through the gaps, causing the fibrous
Penetration into the molded article can be reliably suppressed.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a fibrous formed article used in the present invention.

FIG. 2 is a cross-sectional view of Examples 1 and 2 of a fibrous formed body according to the present invention.

[Explanation of symbols]

 1 fibrous formed body 1a coated surface

──────────────────────────────────────────────────続 き Continuation of front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C04B 30/02 C04B 32/00

Claims (2)

(57) [Claims] 1. A molded product is molded bonded by organic and inorganic binder fiber material, ceramic fiber
-A blanket impregnated with a binder and compression-bonded
The property that gas does not easily enter at least one surface perpendicular to the furnace lining direction of the molded product consisting of multiple layers or multiple layers
A fibrous molded article characterized by being coated with: 2. The fiber material is bound by an organic and inorganic binder.
The ceramic fiber
-A blanket impregnated with a binder and compression-bonded
At least one surface perpendicular to the furnace lining direction of the molded product having a plurality of layers or a plurality of layers is treated so that an organic resin and an inorganic binder which is a component similar to the molded product are present by heating, and a coating material is applied to one surface thereof. And heat-treated after coating to prevent gas penetration
A coating method for a fibrous molded article, characterized in that a coating layer of (1) is formed.