JPS6253612B2 - - Google Patents

Description

BACKGROUND OF THE INVENTION [Technical Field of the Invention] The present invention relates to an apparatus for producing a refractory fiber precursor such as alumina, silica, and zirconia.

[Prior art]

In recent years, fire-resistant fibers such as alumina fibers, zirconia fibers, and silica fibers have been developed as high-temperature insulation materials, reinforcing materials, fillers, and insulators in composite materials. Because these fibers have excellent properties at high temperatures, they are expected to be used not only in the above-mentioned insulation materials, but also in an extremely wide range of applications and development in many industrial fields. It is something.

Conventionally, fire-resistant fibers have been manufactured by different methods depending on their type. For example, alumina-silica fiber (aluminum silicate fiber) is produced by adding boric acid glass, zirconia, chromium oxide (), etc. to a mixture of calcined kaolin, alumina raw material, fireclay, and silicic acid raw material, and then producing it in an electric furnace. It is made into fibers by a blowing process in which it is melted at high temperature and the melt flows out as a trickle and blown away with compressed air or a steam jet, or by a spinning process in which it flows down onto a high speed rotating drum. However, when the alumina value exceeds 60%, the melting point increases and the melt viscosity decreases to about 0.5 poise, so the production of alumina-silica fibers using the above melt spinning method is limited to compositions with an alumina value of 60% or less. be done. In addition, alumina fibers, zirconia fibers, etc. are made into fibers using a solution of aluminum salts such as aluminum chloride or aluminum acetate or an aqueous solution of zirconium salt as a starting material to form a so-called fiber precursor (precursor). It is manufactured by firing at high temperature. The method for producing fire-resistant fibers involving the formation of fiber precursors includes, for example,
U.S. Patent No. 4277269 and Japanese Patent Publication No. 1983-
There is a method described in Publication No. 36726. The former method (US Pat. No. 4,277,269) uses 0.3 to 1.5 mm
A solution for forming a fiber precursor is charged into a hollow rotating disk having a hole, a fiber precursor is obtained by rotating this disk, and then the precursor is fired to produce a refractory fiber. however,
In this method, the solution viscosity must be strictly controlled because when the solution viscosity is high, the spinneret provided in the disk becomes clogged, and when the solution viscosity is low, the solution does not become fibers but scatters as droplets. is necessary. Another drawback is that the fiber diameter and fiber length cannot be adjusted by changing the solution viscosity. On the other hand, the latter method (Special Publication No. 55-36726)
extruding a fiber precursor-forming solution through one or more apertures into an air stream to form a precursor, and then firing the precursor, the air stream displacing the expelled solution; It has a component that flows at high speed in the direction and has a relative humidity of 80% or more. However, this method also has the same drawbacks mentioned above, namely, clogging of the apertures, cutting of the fiber precursor, etc. if the solution viscosity is not suitable, resulting in a large number of shots (non-conformity) in the refractory textile product. fiber particles).

Summary of the Invention [Object of the Invention] The present invention has been made in view of the above-mentioned circumstances, and its purpose is to provide a fiber precursor having no viscosity restrictions when forming a fiber precursor, and to easily adjust the fiber length and fiber diameter. Moreover, it is an object of the present invention to provide an apparatus for producing a precursor thereof, which can obtain high-quality refractory fibers containing no shot (non-fiber particles).

[Structure of the invention]

The present inventors used a viscous liquid, that is, a liquid material having stringability as a raw material for forming the fiber precursor, in manufacturing fire-resistant fibers through the fiber precursor forming step, and The precursor formation step is
The present inventors have found that the two-step process of spinning a viscous liquid and drawing using fluid pressure is effective in achieving the object of the present invention, and has completed the present invention.

That is, the apparatus for producing a refractory fiber precursor of the present invention strings the viscous liquid from the surface of the viscous liquid for forming the refractory fiber precursor to form a primary fiber precursor in the fluid flow, and An apparatus for obtaining a secondary fiber precursor by further stretching the primary fiber precursor using the fluid pressure, the supply terminal to which the viscous liquid is supplied to form the viscous liquid surface; and the supply terminal. a thread terminal that repeatedly moves into and out of contact with the surface of the viscous liquid above;
and an air supply device that forms the fluid flow between the supply terminal and the string terminal.

〔Effect of the invention〕

The following effects can be obtained by the apparatus for producing a refractory fiber precursor of the present invention.

(a) To adopt a two-step formation in which a primary fiber precursor is formed and a secondary fiber precursor is formed by fluid pressure,
No shot generation occurs at all, and high quality refractory fibers and aggregates thereof can be obtained.

(b) There are few restrictions on the starting materials that can be used to prepare the viscous liquid for forming fiber precursors, such as ordinary refractory raw material ultrafine powder, metal salts that can be converted into metal oxides by heating, colloidal alumina, colloidal silica, etc. Various types and shapes of starting materials can be used. Therefore, by preparing a plurality of different types of viscous liquids, spinning these viscous liquids at the same time, and collecting the fibers at one place, different types of refractory fibers can be simultaneously produced and mixed together.

(c) By adjusting the viscosity of the viscous liquid for forming a fiber precursor, the stringing distance of the viscous liquid, the fluid pressure, etc., it is possible to easily change the characteristics of the refractory fiber, such as the refractory fiber diameter and refractory fiber length. can.

[Specific description of the invention]

The apparatus for producing a refractory fiber precursor of the present invention will be explained in more detail.

The viscous liquid for forming a fiber precursor used in the present invention can be turned into a fire-resistant fiber by firing the viscous liquid into fibers. The viscous liquid of the present invention includes a metal salt solution that changes into a metal oxide by heating and baking, a dispersion of refractories such as alumina, silica, zirconia, and magnesia or metal powders such as iron, titanium, and chromium, and polycarbosilane. viscous liquid etc.

Examples of the metal salt include aluminum,
Chlorides of iron, zirconium, titanium, beryllium, chromium, magnesium, yttrium, etc.
These include sulfates, nitrates, formates, acetates, propionates, butyrates, other alkanates, basic alkanates, lactates, silicates, and mixtures thereof.

The dispersoid used in the preparation of the dispersion is as follows:
For example, ultrafine powders of refractories such as alumina, silica, zirconia, and magnesia used in ordinary firebricks, metal powders such as iron, titanium, and chromium, colloidal silica, colloidal zirconia,
Examples include alumina sol. The particle size of the dispersed refractory particles is 1/10 of the fiber diameter of the final refractory fiber.
For example, when the fiber diameter of the desired refractory fiber is 5μ, the particle size is preferably 0.5μ or less. This is because if the particle size of the refractory granules exceeds 1/10 of the fiber diameter of the refractory fiber, the refractory fiber obtained from the refractory granules becomes brittle and easily powders with a slight external force.

The viscous liquid for forming a fiber precursor used in the present invention is prepared by using the above metal salt and dispersoid in combination or each alone. Usually, these metal salts and dispersoids are solid or powdered, so
These are dissolved or dispersed. This medium includes water, hydrocarbons such as hexane and petroleum benzine, halogenated hydrocarbons, monohydric alcohols, phenols, ethers, esters, polyhydric alcohols and their ethers and esters, aldehydes, acetals, ketones, and nitrogen-containing compounds. (nitro compounds, amides, amines), sulfur-containing compounds (such as dimethyl sulfoxide), and mixtures thereof. A non-limiting example of a preferred medium is water from the standpoint of economy and working environment.

In addition, when preparing the viscous liquid for forming fiber precursors,
A viscosity-imparting agent or diluent can be added to adjust the consistency (stringiness). Examples of the viscosity imparting agent that can be used in the present invention include synthetic polymers such as polyethylene oxide, polyvinyl alcohol, and polyacrylic acid;
Examples include cellulose derivatives such as methylcellulose, carboxyethylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, and cellulose phosphate; starch and starch derivatives; and animal and plant mucilages such as pectin, sodium alginate, and agar. The amount of the viscosity-imparting agent and diluent to be added is appropriately changed depending on the fiber length and fiber diameter of the target fire-resistant fiber, that is, the desired viscosity. Furthermore, when preparing the viscous liquid of the present invention,
It goes without saying that various auxiliary agents can be added to impart various properties to the fiber precursor and/or fire-resistant fiber.

In the method of the invention, the formation of the fiber precursor consists of a two-step process. First, the primary fiber precursor is
This is carried out by spinning the viscous liquid from the surface of the viscous liquid for forming a fiber precursor as described above. Threading of the viscous liquid can be carried out using various methods or devices depending on the purpose. For example, first a viscous liquid is applied to the surface of the supply terminal. The string terminal is brought close to the surface of the sticky viscous liquid to cause the viscous liquid to adhere to the string terminal. Next, the string terminal is separated from the viscous liquid surface (and the supply terminal) in reverse, and a filament of the viscous liquid, that is, the primary fiber precursor, is separated between the string terminal and the viscous liquid surface (and the supply terminal). can be formed. However, the present invention is not limited to this method, and by dropping a small amount of viscous liquid,
Further, the viscous liquid can be threaded by adhering the viscous liquid to the contact points of two terminals that have contacted each other and then separating the two terminals.

In the method of the invention, a primary fiber precursor is formed in a fluid stream. The fluid that can be used in the present invention is appropriately determined depending on the type of target fire-resistant fiber and the type of viscous liquid. Examples of this fluid include water, vapors such as acetone and alcohol, and gases such as nitrogen, inert gases, and air. Creating this fluid flow can be done using conventional equipment such as a blower.

The formed primary fiber precursor is placed in a fluid stream and is further stretched by the pressure of the fluid to become a secondary fiber precursor. This pressure is
It can be changed as appropriate depending on the desired fiber diameter and fiber length. After stretching, the yarn, ie, the secondary fiber precursor, can be cut using fluid pressure, a blade, or the like, and then scattered along the flow of the fluid. When scattering the secondary fiber precursor, it is preferable to provide a secondary fiber precursor collecting device on the downstream side of the fluid flow.

Firing of the secondary fiber precursor can be carried out by conventional firing techniques used in the manufacture of refractory fibers.

The method for producing refractory fibers of the present invention will be described in more detail with reference to examples of apparatus that can be used in this method. FIG. 1 schematically shows an example of an apparatus for forming fiber precursors according to the invention. A spinning device 1 for forming a primary fiber precursor from a viscous liquid for forming a fiber precursor has a space 2 therein, a supply terminal 3 is provided at the lower end of this space 2, and a A string terminal 4, which can be moved up and down inside, is provided at the upper end of the space 2.
A viscous liquid supply pipe 5 is connected to the supply terminal 3. A blower 6 is provided upstream of the fluid flow (indicated by its direction and arrow) and directs the fluid flow toward an opening on one side of the space 2 . On the other hand, on the downstream side of the fluid flow, a cotton collector 7 and a suction blower 8 are arranged further downstream. FIG. 2 is a partially enlarged view of the stringing device 1 seen from the upstream side of the fluid flow. The viscous liquid carried to the supply terminal 3 via the supply pipe 5 seeps out from the fine holes provided in the upper part of the terminal 3, and this seeped viscous liquid comes into contact with the thread terminal 4. FIG. 2 shows how the viscous liquid is threaded and the primary fiber precursor 11 is formed by separating the thread terminal from the supply terminal. FIG. 3 is a partially enlarged sectional view of the spinning device 1 showing the state of the yarn over time, and the yarn terminal 4 is in contact with the surface of the viscous liquid 12 attached to the surface of the supply terminal 3. Condition, string terminal 4
is pulled away from the supply terminal 3 to form a relatively thick primary fiber precursor 11, and the thread terminal 4 is further pulled away to form a thin primary fiber precursor 1.
1 is formed.

Next, how to use the example device shown in FIG. 1 and its function will be explained. Source of viscous liquid (not shown)
From there, the viscous liquid is sent to the supply terminal 3 via the supply pipe 5, and a viscous liquid layer is formed on the surface of this terminal. The thread terminal 4, which can move up and down, threads the viscous liquid from the surface of the viscous liquid to form the primary fiber precursor 11, as shown in FIG. During this stringing, a flow of air, that is, a wind, is generated in the space 2 of the stringing device 1 by means of a blower 6 and a suction blower 8. Therefore, the primary fiber precursor 11 formed in the space 2 is stretched and cut by the wind pressure, becomes a secondary fiber precursor 13, and is blown away by the wind. The secondary fiber precursors 13 that are flown and scattered in this way are collected by the cotton collection device 7 on the downstream side, and become an aggregate 14 of cotton-like secondary fiber precursors. The obtained secondary fiber precursor aggregate 14 is fired in a suitable heating furnace to become a refractory fiber.

The example of the apparatus used in the method for producing a refractory fiber of the present invention is not limited to the above-mentioned example, and can be variously modified. That is, viscous liquid can be threaded as in the modified examples shown in FIGS. 4 to 6.

FIG. 4 shows an example of a device in which the thread terminal 4 and the supply terminal 3 are brought into contact and separated by vertical movement using a crank type.

FIG. 5 shows the contact between the thread terminal 4 and the supply terminal 3.
This is an example of a device in which the separation movement is performed in a caterpillar type, in which the supply terminal 3 with viscous liquid attached to its surface contacts the thread terminal 4 downwardly, and both caterpillars move inwardly and upwardly, thereby causing a separation between both terminals. A primary fiber precursor 11 is formed.

FIG. 6 shows an example of an apparatus in which the supply terminal 3 is fixed and the thread terminal 4 is rotated in a water wheel manner to form the primary fiber precursor 11.

Adjustment of the fiber diameter and fiber length of the refractory fiber, that is, the adjustment of the diameter and length of the secondary fiber precursor, is performed by adjusting the viscosity of the viscous liquid, the string distance (for example, the maximum separation between the string terminal and the supply terminal) This can be easily realized by appropriately changing the distance), fluid pressure (for example, wind pressure by a blower and a suction blower), etc.

For example, in order to obtain refractory fibers with a large fiber diameter, it is sufficient to increase the viscosity of the viscous liquid and shorten the string distance. Furthermore, in order to obtain refractory fibers with a small fiber diameter, it is sufficient to reduce the viscosity of the viscous liquid and increase the fluid pressure by increasing the string distance. In order to obtain long fibers, the viscosity of the viscous liquid may be increased and the thread distance may be increased. Conversely, short fibers can be produced by reducing the viscosity of the viscous liquid and shortening the thread distance.

The fireproof fibers have been described above in detail. However, the technical idea of the present invention can be applied not only to fire-resistant fibers but also to non-fire-resistant general organic fibers.

〔example〕

Example 1 30 parts by weight of zirconia fine powder of 0.1μ or less, zirconium oxychloride (zirconium oxychloride)
A viscous liquid was prepared by adding and mixing 50 parts by weight of water with 60 parts by weight of ZrOCl ₂ ), 10 parts by weight of yttrium nitrate, and 5 parts by weight of polyethylene oxide. The viscosity of this viscous liquid was 1000 poise. A zirconia fiber precursor was formed using the fiber precursor forming apparatus shown in FIG. 1, which was equipped with a spinning device as shown in FIGS. 2 and 3. During this primary fiber precursor formation (spinning), the string distance (that is, the maximum separation distance between the string terminal 4 and the supply terminal 3) was 200 mm. Also, the wind speed for forming the secondary fiber precursor (ie, drawing and scattering) was 20 m/sec. The formed secondary fiber precursor was heated to 1300°C and fired. The obtained zirconia fiber had a diameter of 10 μm, a length of 500 m, and a tensile strength of 80 Kg/mm ² .

Example 2 Zirconia fibers were produced in the same manner as in Example 1, except that the string distance was 20 mm and the wind speed for forming the secondary fiber precursor was 50 m/sec.

Regarding the quality of the zirconia fiber obtained by firing at 1300℃, the diameter is 5μ and the length is 100℃.
mm, and its tensile strength was 100Kg/ ^mm2 .

Example 3 90 parts by weight of basic aluminum chloride, 10 parts by weight of ultrafine silica powder of 0.05μ or less, polyvinyl alcohol
A viscous liquid was prepared by adding 80 parts by weight of water to 13 parts by weight. The viscosity of this viscous liquid was 200 poise.

Primary fiber forming device (threading device) shown in Figure 6
A secondary fiber precursor was formed as shown in FIG. At this time, the string distance was approximately 100 mm, and the wind speed was set at 80 m/min to form the secondary fiber precursor.
Seconds.

The alumina fiber obtained by firing at 1100°C had a diameter of 3μ, a length of 300mm, and a tensile strength of 120Kg/ ^mm2 .

Example 4 An alumina fiber was produced in the same manner as in Example 3, except that the amount of polyvinyl alcohol added as a starting material was reduced to 8 parts by weight to reduce the viscosity of the viscous liquid to 80 poise.

The obtained alumina fiber had a diameter of 1μ,
It had a length of 150mm and a tensile strength of 130Kg/ ^mm2 .

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing an example of an apparatus for forming a fiber precursor according to the present invention, Fig. 2 is a partially enlarged view of the spinning device seen from the upstream side, and Fig. 3 shows how the thread is sequentially drawn. FIGS. 4 to 6 are partially enlarged cross-sectional views of the threading device for illustrating the present invention, and FIGS. 4 to 6 are schematic diagrams showing modified examples of the threading device. DESCRIPTION OF SYMBOLS 1... Threading device, 2... Space, 3... Supply terminal, 4... Thread terminal, 5... Supply pipe, 6... Air blower, 7... Cotton collection device, 8... Suction blower, 11...Primary fiber precursor, 12...Viscous liquid,
13...Secondary fiber precursor, 14...Aggregation of secondary fiber precursors.

Claims (1)

[Claims] 1. Spinning the viscous liquid from the surface of the viscous liquid to form a refractory fiber precursor to form a primary fiber precursor in the fluid stream, and further stretching the primary fiber precursor by the fluid pressure. An apparatus for obtaining a secondary fiber precursor, comprising: a supply terminal to which the viscous liquid is supplied to form a surface of the viscous liquid; A string terminal that performs movement;
An apparatus for producing a refractory fiber precursor, comprising an air supply device that forms the fluid flow between the supply terminal and the thread terminal.