JPH042685B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a long-fiber high-temperature heat-resistant cement fiber made of a hydrated product of long-fiber high-temperature heat-resistant cement that can be used for a long time in a high-temperature region, and This relates to a manufacturing method.

(Prior art) Natural asbestos fibers, artificial glass fibers, rock wool, carbon fibers, etc. are known as inorganic fibers and have excellent heat resistance, but fiber materials that can withstand use at high temperatures are generally refractory. - Called fibers, such as titanate cauli fiber, boron nitride fiber, boron fiber, various whiskers (however, only short fibers), high silicic acid quartz fiber, silica alumina fiber (ceramic fiber), metal fiber, etc. be.

Among these, silica-alumina fiber is the most widely used high-temperature insulation material for general industrial use. Silica alumina fiber is generally called ceramic fiber, and is a fiber manufactured from equal amounts of silica and alumina, and small amounts of boron, zirconia, etc.
It can withstand high temperatures in the range of
Used as various insulation and fireproof products.

(Problems to be Solved by the Invention) However, all conventional refractory fibers require high-temperature processes exceeding 1000°C in order to melt and carbonize the materials, and for this reason, Even if mass production technology was established, there was an unavoidable problem that there was a certain limit to its economic efficiency.

Therefore, an object of the present invention is to eliminate the need for a high-temperature process, which is a problem with conventional refractory fibers, to enable simple production, and to have a heat resistance temperature higher than that of ordinary Portland cement, etc. An object of the present invention is to provide a long fibrous high temperature heat resistant fiber having high temperature heat resistance suitable for the purpose of the present invention and a method for producing the same.

(Means for solving the problem) Therefore, as a result of repeated research to find a high temperature heat resistant fiber that does not require a high temperature process, the present inventors found that
Using hydraulic high-temperature heat-resistant cement as a material, we conducted further research with the idea of extruding and obtaining cement fiber material with a diameter on the order of microns through the die pores of an ordinary spinning extruder at room temperature.

As a result, we proposed mixing cement slurry with an inorganic gel-forming raw material, extruding this as a fibrous material with a micron-order diameter through the die pores of an ordinary spinning extruder, and then bringing it into contact with a gelling agent. The present invention has been completed.

According to the present invention, cement slurry that has a slump value of 10 to 20 cm cannot maintain its fibrous shape and therefore cannot be converted into fibers in the past.
By generating inorganic gel material through gelation treatment,
It is possible to make a long fiber body whose shape is maintained and stabilized.

That is, the present invention consists of (1) a mixture of a hydrated and hardened hydraulic high-temperature heat-resistant cement and an inorganic gel material obtained by extrusion through the die pores of an extruder;
Long fibrous high temperature heat resistant cement fiber and (2) hydraulic high temperature heat resistant cement/water are kneaded at a blending ratio of 35 to 55% by weight, and an inorganic gel-forming raw material is further added thereto to obtain a sufficient amount. A long-fiber, high-temperature heat-resistant product characterized in that the resulting thriller is continuously extruded into a gelling tank through the die pores of an extruder, and then the resulting extruded product is cured in air or water. This is a method for manufacturing cement fiber.

In the present invention, as the high temperature heat resistant cement, hydraulic high temperature heat resistant cement such as alumina cement and calcium phosphate salt cement is used,
The amount of water mixed therein is usually a hydraulic cement/water ratio of 35 to 55% by weight.

As an inorganic gel forming raw material for retaining the shape of the extruded product extruded through the pores of the extrusion die into a fiber shape at a stage where the cement has not yet hardened by hydration, for example, an aqueous solution of sodium aluminate (20 to
60% by weight aqueous solution) is added (5 to 20% by weight externally)
Addition) is used, and a conventional screw extruder for spinning is used as the extruder.

In addition, the extruded product that is continuously extruded from the pores of the die is further passed through a gelling tank containing an ammonia aqueous solution, a water glass aqueous solution, etc. as a gelling agent, so that the gel forming raw material is transformed into a gel. be converted into

Furthermore, the long fiber extrudate passed through the gelling tank is wound up in a winding machine if necessary, and then grown in air or water.

(Specific Detailed Description of the Present Invention) The manufacturing method of the present invention will be explained in detail below according to the steps.

The present invention uses hydraulic high-temperature heat-resistant cement, but in order to perform spinning that does not require a high-temperature process, which was a problem in the past, the hydraulic high-temperature heat-resistant cement reacts with water at room temperature. It takes advantage of its hardening properties. Therefore, for the purpose of the present invention, the raw material cement may be any cement material as long as it is hydraulic and exhibits high temperature heat resistance, but it is particularly preferable to use a material that does not cause the slaking phenomenon.

In order to prevent the cement fiber of the present invention from decreasing its compressive and bending strength in the intermediate range of 400 to 800°C, for example, an ultrafine highly active admixture (SiO ₂ ) is used as the anti-slaking agent. , high-temperature heat-resistant cement that supplements and immobilizes calcium hydroxide produced during cement hydration using the reaction formula below (e.g., "Refracrete").
(Product name: Kurosaki Ceramics Co., Ltd.) is preferably used.

Ca(OH) ₂ +SiO ₂ →CxSyHz As mentioned above, "Refracrete" can suppress the occurrence of slaking even when heated or cooled.

Furthermore, as another example, a similar ultra-high temperature fiber can be manufactured using calcium phosphate salt, which is an apatite precursor. Apatite has a melting point of over 1600℃.

However, if ordinary Portland cement, which is not a high-temperature heat-resistant cement, is used, there is a problem that when the product fiber is heated to high temperatures, it softens and its mechanical strength decreases, so it cannot be used for ordinary building materials, etc. Although it is durable, it is not suitable for use as a high-temperature material such as concrete for furnace construction.

In order to produce the cement fiber of the present invention, first, water is added to a hydraulic high-temperature heat-resistant cement, such as "Refractreit," at a mixing ratio of 35 to 55% by weight, and then inorganic A gel-forming raw material, such as a 20-60% aqueous solution of sodium aluminate, is added in an amount of 5-20% by weight of the total, and thoroughly stirred and mixed.

Addition of this inorganic gel-forming raw material is an essential requirement for achieving fiberization of the cement of the present invention.

Next, the obtained cement slurry is injected through the hopper opening of a conventional screw-type extruder for spinning, and is continuously extruded in the form of long fibers through desired die pores (pore diameter of about 5 to 200 μm).

The fibrous slurry extruded from the pores of the die exhibits a slump value of about 10 to 20 cm, and cannot maintain its shape as an extruded long fiber body with a small diameter.

However, in the present invention, by passing it through a gelling tank immediately after it is extruded from the die pores, it is possible to easily maintain its shape as a highly water-retaining gel (hydrogel). This makes it possible to make cement into long fibers, which was previously considered impossible.

As described above, the gelling agent used at this time is a 20-60% aqueous solution of sodium aluminate as an inorganic gel-forming raw material, with an outer weight of 5-20%.
When used in addition, it is preferable to use a 50-60% aqueous solution of water glass.

When the above-mentioned "Refractreat" is used as the hydraulic high-temperature heat-resistant cement, "Refractreat" easily combines with the gel produced from the sodium aluminate, and such a combination is particularly preferable.

Other combinations of inorganic gel materials that retain the shape of high-temperature heat-resistant cement fibers include, for example, calcium hydroxide gel, iron dioxide gel, and calcium carbonate jelly made of calcium chloride and sodium carbonate. Calcium jelly is useful for producing pure high-temperature heat-resistant cement fiber because it separates into liquid and powder crystals when left until the next day.

The extruded product, which has maintained its fibrous shape due to the formation of the inorganic gel, is wound up at a constant speed by a winder installed at the end of the gelling tank, and collected on a drum or the like as necessary. The diameter of the high-temperature heat-resistant cement fiber obtained in this way is determined by the die diameter and winding speed, but is usually 3 μm to 500 μm.
The length can be arbitrarily long or short.

In the present invention, during winding, the cement fibers are held in a gel layer with high water retention properties, so even if they come into contact with each other, they do not come into close contact with each other.

Next, the high-temperature heat-resistant cement fiber wound around a drum or the like is cured in air or water at room temperature. In particular, curing high-temperature heat-resistant cement fibers using water glass in water dissolves and removes excess water glass adhering to the surface of the cement fibers.
This is particularly preferred since it can be removed.

The inorganic gel formed in the present invention has a
Contains a large amount of water (approximately 90% by weight), which contributes to the hydration and self-hardening reactions of the high-temperature heat-resistant cement fiber after extrusion, and is sufficient for the high-temperature heat-resistant cement fiber even when cured in air. This is useful for imparting strength.

That is, in the present invention, since the gel has a high water retention rate and uses a hydrated and self-hardening hydraulic high-temperature heat-resistant cement, in the initial stage after production, the inorganic gel material is used to maintain the shape (shape retention). ) The long, narrow diameter cement becomes hydrated and hardens over time and gradually develops its original strength.

The mechanical strength of the high temperature heat resistant cement fiber provided by the present invention varies depending on the type of hydraulic high temperature heat resistant cement and the type and content of the inorganic gel material, but is approximately 5000 to 10000 Kgf/cm ² . In addition,
The high temperature heat resistant cement fiber of the present invention has little anisotropy in mechanical strength and is isotropic.

In particular, when a calcium phosphate salt-based material is used as the hydraulic high-temperature heat-resistant cement in the present invention, the following effects are exhibited.

Calcium phosphate salt based cement fiber is
There is no decrease in hot strength up to 1000℃, it can withstand high temperatures up to 1800℃ even in oxidizing atmospheres, it is thermally stable, has high fire resistance, has extremely low water absorption, and there is no need to worry about slaking. There are no problems with carbonation and it has excellent adhesion to cementitious binders, especially at high temperatures.

(Example) An embodiment of the present invention will be described.

100 parts by weight of "Refracrete", 20 parts by weight of water,
Sodium aluminate as a raw material for inorganic gel formation
Add 15 parts by weight of a 40% aqueous solution and thoroughly stir and mix to obtain a cement slurry.

In addition, "Refracrete" (product name: Kurosaki Ceramics Co., Ltd.)
) is _SiO2 : 45% by weight, CaO: 39% by weight,
Al ₂ O ₃ : 9% by weight, Fe ₂ O ₃ : 3% by weight, MgO: 1.5
It is a hydraulic powder having a composition of % by weight.

Next, this cement slurry is injected into a screw-type extruder for ordinary spinning through its hopper port, and is continuously extruded from the die pores (pore diameter of about 150 μm) at a constant extrusion speed (15 cm/sec.). The gelling agent is extruded into the gelling agent liquid in the gelling tank.

Water glass is used as a gelling agent in this gelling tank.
Filled with 60% aqueous solution.

As a result, a flexible cement mixture made into long fibers with a diameter of 150 μm is obtained.

Next, the extruded product, which has maintained its fibrous shape through the formation of the inorganic gel material, is moved at a constant speed (15 cm/sec) by a winder installed at the end of the gelling tank.
It is wound up.

Thereafter, the cement fiber wound around a drum or the like is cured in air at room temperature for three days.

The tensile strength of the high temperature heat resistant cement fiber obtained as above is about 120Kgf/ ^cm2 ,
The residual tensile height at room temperature after being held at 650°C for 1 hour was 60 kgf/cm ² .

Next, the cement fiber with a length of 5 cm and a diameter of 135 μm obtained by the above air curing was
When 10 parts by weight of the cement fiber was mixed and applied as a heat-resistant reinforcing material, the tensile strength of the molded product at 20°C was improved by 80% compared to the case where the cement fiber was not mixed.

(Effects of the Invention) As is clear from the above description, according to the present invention, cement material can be made into fibers by a simple method, and it has excellent mechanical strength, heat resistance, moisture permeability, and air permeability. The present invention can provide a high-temperature heat-resistant cement fiber suitable as a material for furnace construction, etc., which has excellent properties and bulkiness, and has the following excellent effects.

The production of the high-temperature heat-resistant cement fiber of the present invention is extremely simple and suitable for mass production, and is very advantageous compared to the production of other conventional fibers in that it does not require high-temperature treatment steps. Therefore, manufacturing costs are extremely low, and manufacturing equipment can be unmanned.

By using a high-temperature heat-resistant cement-based material to provide long-fiber high-temperature heat-resistant cement fibers that can be used at high temperatures for long periods of time, the material has excellent rupture strength when heated at high temperatures.

The high-temperature heat-resistant cement fiber of the present invention is a high-temperature heat-resistant cement fiber, and does not contain any organic compounds.
When mixed and used as a reinforcing material for concrete for furnace construction, for example, it is compatible with cement-based binders, has excellent adhesion, can be integrated very well, and can withstand high temperature heating.

When the high temperature heat-resistant cement fiber of the present invention is used as a composite material for a cementitious binder,
The adhesive force between the fibers of the present invention and the binder is large, and the strength of the cementitious binder also sufficiently transmits the stress from one high temperature heat resistant cement fiber to another high temperature heat resistant cement fiber through shear force. The stress applied to the fiber is equalized, making it extremely effective as a composite material with a cementitious binder.

The high-temperature heat-resistant cement fiber of the present invention is bonded with an inorganic gel material, so unlike when organic gel materials are used, no harmful gases are generated when heated to high temperatures, and no harmful gases are generated due to decomposition, foaming, etc. It is safe and stable because it does not collapse.

Claims (1)

[Scope of Claims] 1. Long-fiber high-temperature heat-resistant cement fiber made of a mixture of a hydrated and hardened hydraulic high-temperature heat-resistant cement and an inorganic gel material obtained by extrusion through die pores of an extruder. 2. The long fibrous high temperature heat resistant cement fiber according to claim 1, wherein the hydraulic high temperature heat resistant cement is a calcium phosphate salt. 3 Mixing ratio of hydraulic high temperature heat resistant cement/water is 35~
55% by weight of the long fibrous high temperature heat resistant cement fiber according to claim 1. 4. The long fiber high temperature heat resistant cement fiber according to any one of claims 1 to 3, wherein the inorganic gel material is alumina gel. 5 Hydraulic high temperature heat resistant cement/water mixing ratio is 35~
The two are kneaded to a concentration of 55% by weight, the resulting slurry is continuously extruded into a gelling tank through the die pores of an extruder, and the resulting extrudate is then cured in air or water. A method for producing long-fiber high-temperature heat-resistant cement fiber.