JPS62110919A - Production of alumina silica fiber precursor and device therefor - Google Patents

Abstract

PURPOSE:To obtain an alumina silica fiber precursor hardly containing nonfibrous material, by spinning a fiber stock solution using plural protruded nozzles set protrusively at an outlet side of the fiber stock solution of a ring- shaped nozzle plate laid at a peripheral end part of a hollow disc plate. CONSTITUTION:A fiber stock solution is fed from an inlet pipe 2 through a funnel-shaped rotary disc plate to a ring-shaped nozzle plate 3 and passed through plural protruded nozzles 4 by centrifugal force caused by high-speed rotation of the rotary disc. The spun solution is provided with spinning force by hot air jetted from an air nozzle of a ring-shaped annular material 8, further dried by hot air for collecting fibers and collected on a net.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method and apparatus for producing an alumina-silica fiber precursor, and particularly to a high-quality alumina-silica fiber precursor containing almost no non-fibrous material (hereinafter referred to as shot). The present invention relates to a method for producing an alumina-silica fiber precursor and an apparatus therefor.

[Prior Art] In recent years, alumina-silica short fibers have attracted attention as a light heat insulating material for high temperatures of usually 1:100° C. or higher, and various methods for producing the fibers have been proposed.

For example, in Japanese Patent Publication No. 44-17751, /I, 0
A fiber stock solution having a viscosity of 00 to 4.500 c, p,
A method for producing heat-resistant alumina-silica fibers has been reported, in which fibers are spun using a nozzle that has small-diameter holes directly provided at the peripheral end of a rotating disk.

On the other hand, alumina-silica short fibers have been extensively researched for use in composite materials such as FRM, and in this case, shot, which is contained in small amounts in alumina-silica short fibers, which is of little concern in high-temperature insulation applications, is used in FRM products. 11 had a negative impact on the improvement of strength and wear resistance. Similarly, there are many cases where shot quality is a hindrance to expanding the use of alumina-silica short fibers.

[Problems to be solved by the invention] In such cases, it is desirable to use long fibers that do not contain shot quality, but since they are economically disadvantageous compared to short fibers, shot quality is generally used. It is common practice to refine and utilize alumina-silica short fibers in order to remove them in advance. In addition, it is generally possible to reduce the shot amount to a certain extent by reducing the spinning capacity to a certain extent, which is common to ordinary spinning methods.
Nails: The limit is about 1'c%.

Further, the above-mentioned Japanese Patent Publication No. 17751/1989 does not describe a method for producing high-quality alumina-silica short fibers containing almost no silica.

The present invention was completed as a result of intensive research in view of the above circumstances, and it contains almost no shot quality and can be directly used for FIIM or inorganic paper where shot quality is a concern. The object of the present invention is to provide a method and apparatus for producing a high-quality alumina-silica fiber precursor that can be produced at almost the same cost as the fiber cost.

[Means for Solving the Problems] Namely, 1. The present invention provides a high quality alumina-silica fiber precursor containing almost no non-fibrous materials from a fiber stock solution consisting of a mixed solution of an aqueous aluminum compound solution containing an organic polymer and a silica compound. A method for producing a fiber stock solution is characterized in that the fiber stock solution is spun using a plurality of protruding nozzles protruding from the fiber stock solution output side of a ring-shaped nozzle plate provided at the peripheral end of a hollow rotating disk. A method for producing an alumina-silica fiber precursor, and producing a high-quality alumina-silica fiber precursor containing almost no amorphous material from a fiber stock solution consisting of a mixed solution of an aluminum compound aqueous solution containing alumina and a silica compound. In the apparatus, a link-shaped nozzle plate provided at the peripheral end of a hollow rotating disk is provided with a protrusion protruding from the spinning hole D; This is an apparatus for producing an alumina-silica fiber precursor, characterized in that it is provided with a plurality of protruding nozzles having holes therein.

Hereinafter, the present invention will be explained in detail.

In the present invention, alumina-silica fiber refers to an inorganic fiber containing 70% by weight or more of 1203min and 30% by weight or less of 5i02min, and alumina-silica fiber precursor refers to a fiber obtained by spinning a fiber stock solution under specific conditions. Refers to the fibrous II material that has just been removed, and which also contains water and organic matter.

In the present invention, the fiber stock solution is a mixture of an aqueous solution of an aluminum compound such as aluminum oxychloride, an aqueous solution of a silica compound such as silica sol, and an organic polymer such as polyvinyl alcohol, and further additives are added as necessary. It refers to the product that has been concentrated and adjusted to a specified viscosity.

In the present invention, the aluminum compound may be one or more selected from basic chloride, k11 acetate, and basic nitrate of aluminum. Among these, the basic chloride of aluminum has the formula AI*(0
11) Aluminum oxychloride represented by nclm (where n+m"6) is preferred.

In the present invention, the a-polymer may be any polymer that imparts a spinning-aiding effect to the fiber stock solution, and is usually a medium-sized polymer such as polyvinyl alcohol, partially saponified polyvinyl alcohol, or polyvinyl acetate, or a grade-f F. , :: is preferable, and specifically, a water-soluble one with an average degree of filtration of about 1,700 to 2,000 is preferable.

In the present invention, oxides such as magnesium, boron, and phosphorus can also be used as additives that impart preferable physical properties to alumina-silica fibers.

Furthermore, a silicone-based or alcohol-based antifoaming agent or the like may be added to the fiber stock solution.

The fiber stock solution in the present invention is prepared by mixing an aqueous solution of an aluminum compound containing the above-mentioned organic polymer with an aqueous solution or colloidal solution of a silica compound and additives, and then concentrating the mixture under reduced pressure to adjust the viscosity and impart the necessary stringability. The spinning process is performed using

It is desirable that the fiber stock solution retains its spinnability for several days or more, but in order to maintain such stable spinnability, the fiber stock solution's pl+, water-soluble organic polymer, aluminum compound, silica compound, and additives are required. It is affected by the type of agent, the blending ratio of each component, viscosity, etc.

In addition, when aluminum oxychloride is used as the aluminum compound, the molar ratio of AI/CI is 1.5 to 2.2.
, preferably 1.7 to 1.9.

If the cell ratio is less than 1.5, the alumina solid content will be too low and spinning will be disadvantageous, and if it exceeds 2.2, the properties of the solution will become unstable.

In the present invention, the content j, t of the organic polymer in the fiber m J'; If the weight is less than 101%, there will be no spinning assistance effect, and even if it exceeds 101%, the spinnability effect will not change, which is uneconomical.

In addition, the content of aluminum compounds in the fiber stock solution; 11 is 70% or more based on the inorganic solid content, preferably 72 to 95%! Tf product - % is desirable, and the content of silica compound: I: is based on the inorganic solid content: IO modified r
11% or more, preferably 5 to 28%, is desirable.

In the method for producing an alumina-silica fiber precursor of the present invention, the TA fiber stock solution prepared as described in L is protruded from the fiber stock solution outlet side of a ring-shaped nozzle plate provided at the peripheral end of a hollow rotating disk. Spinning is performed using a plurality of protruding nozzles.

To explain the spinning method more specifically by showing one embodiment of the manufacturing method of the present invention, the inner diameter of the nozzle is about 0.2
mm to about 0.4 mm, and the ratio of the depth of the spinning hole to the inner diameter of the nozzle is 5 to 20. A spinning device equipped with a plurality of protruding nozzles on the circumferential end of a rotating disk, which is made of the above-mentioned compound, is used. The viscosity of lI# stock solution at 20°C is t, ooo~
I11,0 old 1c, p, preferably l, 500-3
, 500c, p, and then introduced into the rotating disk, and when the fiber stock solution introduced into the rotating disk passes through the nozzle hole and is spun, it is spun at a Jg that almost does not contain shot. In order to apply sufficient pressure to the fiber stock solution inside the rotating disk, the circumferential speed of the peripheral end of the rotating disk is: 1O~60 m
/see, preferably 37 to 52 m/sec, is applied to the rotating disk, and the spinning disk is passed through a protruding nozzle to perform spinning.

The inner diameter of the nozzle of the protruding nozzle is approximately 0.2 ram to approximately 0.4 ram.
mm, preferably 0.25-0. : 15 mm is desirable; if the nozzle diameter is less than about 0.2 mm, the nozzle diameter is too small and clogging is likely to occur; if it exceeds about 0.4 mm, the spinnability will be poor and shots will occur.

In addition, the ratio of the depth of the spinning hole to the inner diameter of the nozzle is 5 to 211.
, preferably 10 to 15 to 9jl; if it is less than 5, the spinnability will be poor and shots will occur; if it exceeds 20, crystallization of the protruding nozzle will occur (which will be an obstacle during spinning).

The fiber stock solution generally contains a large amount of inorganic solids as its viscosity increases, so the production capacity is affected, or in the present invention, the fiber stock solution is Viscosity at 20°C is 1, OO~10. Mouth Ql
lc, p9, preferably l, 500-3.501
1 (: , I) , ;61f! True, l, old 1
11c, I) If it is less than 1, the spinnability is poor and causes shot occurrence, + 1111, tl +] Oc,
If it exceeds p, the protruding nozzle is likely to become clogged.
This can cause shots to occur and cause problems.

Further, when examining the characteristics of the fiber stock solution used in the present invention in detail, it is found that when the viscosity exceeds approximately 1,000 c,p, the increase in solid content due to the increase in viscosity has a large impact on the manufacturing capacity. It turns out that it does not increase as much.

For example, Al□Off minute 8 fl Tj! ;5%, 5i
The solid content of the raw solution of alumina-silica fiber is viscosity 1.000c, p and 10
,000c,p, there is only a difference of about 3% in the stock solution. Furthermore, the stability of the fiber stock solution and the maintenance of the small-diameter protruding nozzle part of the rotating disk are generally better as a lower viscosity stock solution is used. In order to obtain such spinnability, the viscosity of the fiber stock solution to be spun under the specified conditions of the nozzle hole is 1.000 to 1,000 c, p, preferably 1,000 to 1,000 c, p.
It is preferable that the viscosity is in a relatively low viscosity range of 500 to 1, 500 c, p.

In addition, the circumferential speed of the rotating disk peripheral end is 30 to 60 m/sec.
.

Preferably 37 to 52 m/sec, 30+s
If it is less than 60 m/sec, the spinnability will be poor and shots will occur, and if it exceeds 60 m/sec, the circumferential speed will be too high, which will likely cause practical difficulties, and the spun fiber will become thinner than necessary, which is not preferable.

Next, an apparatus for producing an alumina-silica fiber precursor according to the present invention will be described.

FIG. 1 is a sectional view showing an example of a rotating disk spinning apparatus used for producing the alumina-silica fiber precursor of the present invention.

In FIG. 1, an introduction tube 2 for supplying the fiber stock solution is inserted into the hollow rotating shaft 9 of the funnel-shaped rotating disk body l installed in the direction of the water flow, and its tip is connected to the inclined surface IO of the rotating disk body l.
It stands out. The peripheral end of the inclined surface 9 of the rotating disk main body l is fixed to one side of the ring-shaped nozzle plate 3 with bolts 5, and the fourth part 6 is fixed to the other side of the ring-shaped nozzle plate 3 with screws 7, A closed hollow space 11 is formed. A protrusion 12 is provided protruding from the outer peripheral surface of the ring-shaped nozzle plate 3 on the spinning dope exit side, and a plurality of protrusion nozzles 4 each having a spinning hole 13 formed through the protrusion 12 are provided.

A link-shaped nozzle plate 3 is provided on the outside of the rotating disk main body l.
An annular body 8 having a diameter larger than that of the conventional one and having a large number of air nozzles perforated on its surface is installed.

FIG. 2 is a partial sectional view showing one example of a protruding nozzle, and FIG. 3 is a partial sectional view showing another example. d is the inner diameter of the nozzle, D
is the outer diameter of the nozzle, L is the length of the protrusion, and T is the depth of the spinning hole.

In the present invention, as a result of performing a spinning test using the above-mentioned fiber stock solution, d was about 0.2 mm to about 0.4 mm, and Q/
It has been found that good spinning can be carried out at a ratio of d of 5 to 20.

In this case, the wall thickness of the nozzle is approximately 0.1 mm to approximately 0.5 mm.
It is preferable that D is about 0.4 mm to about 1.4 m.
It is desirable that it is m. Further, L is desirably at least D or more in order to prevent the spinning dope passing through the nozzle hole from adhering to the surface of the ring-shaped nozzle plate.

Furthermore, by making L at least as long as D,
Since the thickness of the ring-shaped nozzle plate is thinner by the length L compared to the case where no protrusion is provided, it is possible to reduce the weight of the link-shaped nozzle plate by 1 yen.

Next, an example of a method for manufacturing an alumina-silica fiber precursor using the apparatus shown in FIG. From 2, it is supplied to a link-shaped nozzle plate 3 through a waxy rotating disk, and is spun by passing through a plurality of protruding nozzles 4 due to the centrifugal force caused by the high-speed rotation exerted on the rotating disk.

The yarn spun by centrifugal force is slightly thicker than the diameter of the rotating disk installed around the outer circumference of the rotating disk.
The spinning force is further assisted by the hot air blown from the air nozzle of the closed annular body 8, and at the same time, it accompanies some drying, and the net surface is dried by the hot air that makes LI the cotton collection.
It is collected into alumina-silica fiber precursor.

In FIG. 1, a ring-shaped nozzle plate 3 having a plurality of protruding nozzles 4 is fixed to a rotary disk main body l to which power is applied by bolts 5, so that it can be disassembled.

Therefore, when cleaning the protruding nozzle 4, since the fiber stock solution is water-soluble, if only the ring-shaped nozzle plate 3 is washed or soaked in water or warm water for a few minutes, the liquid pool in the nozzle part can be easily eliminated.

The ring-shaped nozzle plate 3 capable of resolving i+f is further fixed by the lid part 6 and the screws 7, or there is no problem even if the four parts 6 and the ring-shaped nozzle plate 3 have a body structure. do not have. 4(a) and 4(b) show this link-shaped nozzle plate 3 having a plurality of disassembly protruding nozzle parts, FIG. 4(a) is a sectional view, and FIG. 4(b) is a sectional view. It is a front view showing a part.

In addition, as a means for forming the protruding nozzles, a plurality of openings considerably larger than the protruding nozzles are provided in the ring-shaped nozzle plate in advance, a fitting member provided with the protruding nozzles is fitted into the openings, and the adhesive is applied to the ring-shaped nozzle plate. It can be formed by fixing with a vice.

To give specific examples, FIG. 5 is a partial explanatory diagram of the injection needle 14, and FIG. 6 is an explanatory diagram of a protruding nozzle formed using the injection needle, or as shown in FIG. In order to use the needle as a protruding nozzle, a needle cut into a predetermined length is used, and this is used as a ring-shaped nozzle plate 3 as shown in FIG.
Fix it to the hole made in advance using adhesive 15 or the like.

In this way, for example, by cutting a hypodermic needle to a predetermined length and using it, it is possible to create a nozzle part by cutting a small diameter hole into a material of a predetermined thickness. It is a very effective method when it is necessary to increase the ratio between the depth and the diameter of the nozzle hole.

[Function] In the present invention, since the fiber stock solution is spun using a protruding nozzle protruding from the fiber stock solution outlet side of the link-shaped nozzle play 1 provided at the peripheral end of a hollow rotating disk, the fiber stock solution and The fiber stock solution is spouted from the tip of the protruding nozzle with a small contact area without contacting the ring-shaped nozzle plate, and spinning is performed, so the affinity with the protruding nozzle decreases and the spinning hole exits "1". It is possible to perform continuous and uniform operation without causing dripping of the fiber stock solution, hemispherical lumps, thread breakage, etc., and it is possible to produce high-quality alumina-silica fiber precursor with less shots. It is estimated to be.

[Example] Next, an example will be shown to explain the present invention in more detail.

Reference example The shot content 1.1 measurement method in alumina-silica short m and m is generally difficult, and there is no standardized measurement method yet.
As a measurement method, the present inventors forcibly stirred alumina-silica short fibers in water, then gently poured the supernatant slurry into another container, and collected and separated the shot material deposited at the bottom of the original container through filter paper. We devised a method to determine the shot content using the following method. In this measurement method, the slurry liquid was purified three times, and the shot contents collected were totaled to determine the shot content in terms of weight percentage. As an example of measurement using the same method, an example of measurement results for shot content in currently commercially available alumina-silica short fibers is shown below.

■Alsen Bulk (manufactured by Denki Kagaku Chogyo ■).

Composition: Al2O:+/5i02=80/20 product) Shot content: 3 to 5% ■Saphir bulk (manufactured by ICI).

Group I&, : AhO:+/5iO2=95/5
) Shot content: 3% Example 1 In order to embed a syringe needle to be used as a protruding small diameter nozzle on the circumferential edge of a rotating disk with an outer diameter ZO of 11 mm, 48 holes with an inner diameter of 7 mm are drilled at equal intervals, and the inner diameter 0.25m5
, use a syringe needle with an outer diameter of 0.46 mm and a needle length of 3111f.
The 48 pieces cut into fl were fixed using a metal adhesive, and a spinning device was set as shown in FIG. Next, aluminum oxy111ide solution and silica sol were added to
Add 7 tons of polyvinyl alcohol based on the inorganic solid content to the mixture at a ratio of t+ tons:, :,%,
After performing the C compression operation, the viscosity at 211'C was 3.0.
Adjusted to become the old 1c, p. This fiber stock solution was spun at a rotation speed of 4,000 rpm (peripheral speed 42
When the fiber was spun under the following conditions (m/5ec), an alumina-silica fiber precursor with almost no scints was obtained. After this precursor was heat-treated in a conventional manner to obtain an aluminium-silica fiber, shot j11° was determined to be 411% by the method described above, and it was found to be 0.3% by weight. Also, the ta of this fiber,
*The diameter was about 3 to 5 pots.

Example 2 Fiber stock solution A1□03 min 95% by weight, SiO□ min 5
When the fiber stock solution preparation and spinning operation were performed under the same conditions as in Example 1 except for the weight percentage, an alumina-silica fiber precursor with almost no shot was obtained. After heat-treating this precursor to make alumina-silica fiber using the usual method, the shot amount was measured using the method described above (], 5
The weight was 5. Also, the fiber diameter of this fiber is almost 3
Some were ~5μ.

[Effects of the Invention] As explained above, according to the production method of the present invention, a high-quality alumina-silica fiber precursor containing almost no shot quality can be provided at a low cost, and the high-quality alumina-silica fiber precursor The body undergoes a normal heat treatment process to become high quality alumina silica fiber, which is suitable for those who dislike shot quality, such as FR.
The fiber can be used directly for M applications, etc.

Moreover, since the spinning device of the present invention is equipped with a protruding nozzle, it is much less likely to get dirty at the circumferential edge of the disk due to high-speed rotation, compared to a spinning device in which a small-diameter opening is provided directly at the circumferential edge. It is very effective in preventing the occurrence of shots.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing an example of a rotating disk spinning apparatus used for producing the alumina-silica fiber precursor of the present invention, FIGS. 2 and 3 are cross-sectional views each showing an example of a protruding nozzle, and FIG.
Figure (a) is a cross-sectional view of the ring-shaped nozzle plate, and Figure 4 (
b) is a front view showing a part of the ring-shaped nozzle plate;
FIG. 5 is a partial explanatory view of the injection needle, and FIG. 6 is an explanatory view of a protruding nozzle formed using the injection needle. ■908 rotating disc body 200. Introductory tube 301. Ring-shaped nozzle 400. Projection nozzle plate 509. Bolt 690. Lid part 701. B
800. Annular body 986. hollow rotating shaft
10. ,, Inclined surface ■10. Medium space part 12. ,,
Projection +3. ．． ．． Spinning hole +4. ,,syringe needle+
5. ,,Glue dlo, Nozzle inner diameter,
Depth of spinning hole D, 1. Nozzle outer diameter 00. Length of protrusion Applicant Denki Kagaku Kogyo Co., Ltd. Agent Noriwa Watanabe 1 Figure 1 E1 ≥ Norm Figure 2

Claims (4)

[Claims] (1) In a method for producing a high-quality alumina-silica fiber precursor containing almost no non-fibrous material from a fiber stock solution consisting of a mixed solution of an aluminum compound aqueous solution containing an organic polymer and a silica compound, the fiber stock solution is A method for producing an alumina-silica fiber precursor, which comprises spinning using a plurality of protruding nozzles protruding from the fiber stock solution outlet side of a ring-shaped nozzle plate provided at the peripheral end of a rotating disk. (2) In an apparatus for producing a high-quality alumina-silica fiber precursor containing almost no amorphous material from a fiber stock solution consisting of a mixed solution of an aluminum compound aqueous solution containing an organic polymer and a silica compound, the periphery of a hollow rotating disk is used. A ring-shaped nozzle plate provided at the end has protrusions protruding from the spinning stock solution outlet side of the ring-shaped nozzle plate, and a plurality of protruding nozzles are provided in which spinning holes are drilled through the protrusions. An apparatus for producing an alumina-silica fiber precursor, which is characterized by: (3) A ring-shaped nozzle plate is provided with a plurality of openings, and a fitting member having a protruding nozzle is fitted into the opening and fixed with an adhesive or the like, as claimed in claim 2. equipment. (4) The device according to claim 3, wherein the fitting member is an injection needle.