JP3300516B2 - Ceramic fiber yarn - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to ceramic fiber yarns, and more particularly, when a ceramic fiber yarn is heated at an elevated temperature, the crystal structure of the filaments constituting said yarn transitions substantially to a mullite crystal structure. Related to ceramic fiber yarns.

[0002]

2. Description of the Related Art Ceramic fiber yarns (hereinafter sometimes referred to as yarns) made of ceramics represented by alumina are used for various heat-resistant applications because of their excellent heat resistance. In particular, the yarn proposed in Japanese Patent Publication No. 61-32405 has a polycrystalline structure in which the filament has a crystalline structure of transition alumina crystal. However, when the yarn is exposed to a high temperature, the filament has a crystalline structure. Transition to mullite crystal structure. For this reason, compared with a ceramic yarn in which α-alumina crystals are generated by heating at a high temperature, it can have flexibility even at a high temperature.

[0003]

Since the yarn proposed in the above-mentioned Japanese Patent Publication No. Sho-A-Kyo-Kyo can have flexibility even at a high temperature, a woven or knitted fabric is used for lining a firing furnace. ing. By the way, such a yarn is obtained by spinning a spinning stock solution substantially free of a chloride component such as a basic aluminum chloride component, and the obtained yarn contains substantially no chlorine. If a spinning solution containing a chloride component is used, the weaving properties and knitting properties of the resulting yarn are reduced, and yarn breakage and fluff are likely to occur during weaving or knitting. However, the spinning dope containing the basic aluminum chloride component has good spinnability and can increase the productivity of yarn. On the other hand, for example, when a spinning solution containing a water-dispersible alumina sol or a water-soluble organic aluminum salt is used instead of the basic aluminum chloride component, the spinnability is lower than that of the spinning solution containing the basic aluminum chloride component. And the productivity of the yarn decreases. Therefore,
An object of the present invention is a yarn composed of filaments having a polycrystalline structure mainly composed of transition alumina crystals and obtained by using a spinning dope containing a basic aluminum chloride component having good spinnability. It is an object of the present invention to provide a yarn which can improve the knitting property and knitting property and, when heated at a high temperature, changes the crystal structure of the filament to a mullite crystal structure.

[0004]

Means for Solving the Problems The present inventors have studied to achieve the above object, and as a result, the weaving property of the yarn was measured by using a wire having a diameter of 0.5 mm of the filament constituting the yarn. It has been found that the hanging strength has the greatest effect, and that the yarn having a hooking strength equal to or higher than a predetermined value has good weavability and knitting, and has reached the present invention. That is, the present invention relates to a spinning dope containing a silica sol component and a basic aluminum chloride component, which is spun and baked.
33 consists filament group constituted by wt% and filaments formed by a and ceramic fiber yarn crystal structure of the filament is a polycrystalline structure consisting mainly transition alumina crystal, said filaments
At least some of the filaments that make up the
Surface shape is flat and twisted at longitudinal intervals
Is a flat filament formed with a diameter of 0.1 mm for any 20 filaments constituting the yarn.
The average value of the hooking strength measured using a 5 mm wire is
Oh at ^{3.7 × 10 -2 ~ 2.5 × 10} -2 N ( Newton)
Rutotomoni, when performing heat treatment of the pre-Symbol yarns 30 minutes at 1400 ° C., in a ceramic fiber yarn, characterized in that the transition in the crystal structure gum light crystal structure of filaments constituting the yarn after the heat treatment .

[0005] In the present invention having such a configuration, the yarn breakage during weaving or knitting can be reduced by setting the knot strength of the yarn to 314 to 200 dyn / TEX or more. Moreover, the yarn mixing ratio to total filament group of polarized flat filament is 10% or more can exhibit combined flexibility while having high knot strength. Furthermore,
The length (x) of the long side at which the straight line length connecting two points located on the periphery of the filament cross section is the longest, and the short length at which the straight line length crossing the cross section at right angles to the long side is the longest Yarns comprising flat filaments having a ratio (x / y) to the side length (y) of 1.1 to 3 can increase the strength of the yarn while maintaining the flexibility of the yarn. In such a flat filament, if the twisted portions formed at intervals in the longitudinal direction exist every 10 to 500 μm, the strength of the yarn can be further increased.

[0006]

According to the yarn according to the present invention, a spinning solution containing a basic aluminum chloride component having good spinnability is spun to convert the filament crystal structure into a mullite crystal structure at a high temperature. And increase the yarn productivity. Moreover, the filaments constituting this yarn have a higher hooking strength than the filaments constituting the conventional yarn obtained by spinning a spinning dope mixed with a basic aluminum chloride component, and are suitable for weaving and knitting. Properties can be improved, and generation of fluff and the like in the weaving process and the knitting process can be prevented.

[0007]

SUMMARY OF THE INVENTION In the present invention, a spinning dope containing a silica sol component and a basic aluminum chloride component is used as a spinning dope. As such a silica sol component, an acidic aqueous dispersion of colloidal silica can be suitably used, and as the basic aluminum chloride component, a basicity of 70% is used.
% Or more of basic aluminum chloride [Al ₂ (OH) _n Cl
_6-n ; 0 <n <6] can be suitably used. However, the basicity is represented by n / 6 × 100. The yarn composition obtained by spinning and baking such a spinning dope has an alumina component of 6%.
It is important that the content of the yarn is 7 to 75% by weight, the content of the silica component is 25 to 33% by weight, and the filament constituting the yarn has a polycrystalline structure mainly composed of transition alumina crystals. Here, in the case of the yarn in which the alumina component is more than 75% by weight and the silica component is less than 25% by weight, the filaments constituting the fired yarn have a polycrystalline structure mainly composed of transition alumina crystals, but 1400. Heat treatment at a high temperature of not less than ℃ generates α-alumina crystal having a large crystal size, and the yarn becomes extremely brittle. On the other hand, in a yarn in which the alumina component is less than 67% by weight and the silica component exceeds 33% by weight, 1%
During heat treatment at a high temperature of 400 ° C. or more, embrittlement occurs due to generation of cristobalite.

According to the present invention, the fired yarn is
When a heat treatment was performed at 00 ° C. for 30 minutes, the crystal structure of the filament constituting the yarn after the heat treatment was
Ri by polycrystalline structure consisting of the heat treatment before the transition alumina crystal
It is important that you are migrating to beam light crystal structure. The yarn that has transitioned to the mullite crystal structure by the heat treatment under these conditions can exhibit sufficient strength and flexibility although its strength and flexibility (flexibility) are slightly lower than before the heat treatment. On the other hand, in the heat treatment in this condition, the yarn transition alumina crystal without going to beam light crystal structure remains, further continuing the heat treatment at 1400 ° C., remaining though transition alumina crystal α- alumina Transforms into crystals, and the strength and flexibility of the yarn rapidly decreases. In this respect, 1400 ° C., by the heat treatment for 30 minutes, the migrated yarn beam light crystal, be further continued to heat treatment at 1400 ° C., compared to the yarn transition alumina crystal is left, the yarn The strength and flexibility decrease at a slow rate, and the strength and flexibility of the yarn can be maintained for a long time under heating.

In the present invention, for any 20 filaments constituting the fired yarn , a diameter of 0.5 m
The average value of the hooking strength measured using a wire of m is 3.7.
It Ru Ah at ^{× 10 -2 ~ 2.5 × 10 -2} N is the time of textile, it is possible to reduce the generation of fluff as possible. This
Lower limit of the hooking strength of 3.0 × 10 ^-2 N, especially 3.5 ×
It is preferably 10 ⁻² N. Further, the knot strength of such yarn, it is 314~ 200dyn / TE X is, when the textile, preferably in order to be able to reduce the cross-sectional yarn as much as possible. The lower limit of the knot strength of the yarn, 2 30dyn / TE X
, It is preferable that the particular 2 80dyn / TE X.

Here, the hooking strength of the filament was measured by the method shown in FIG. In FIG. 4, both ends are gripped by a gripping member 64 at a hook formed at the tip of a stainless steel wire (hereinafter, may be simply referred to as a wire) 66 having a circular cross section and erected on a base 68. After the loop-shaped filament 62 is hooked, the clamp 60 of the gripping member 64 is pulled in the direction of arrow B, and the load resistance of the filament 62 is measured. The hooking strength of the filament measured by the method shown in FIG. 4 differs greatly depending on the wire diameter. FIG. 6 shows the hooking strength of the filaments measured by the method shown in FIG. 4 while changing the wire diameter for different types of filaments. By the way, the fluff that occurs during weaving is
In many cases, the filament is cut by the weaving and knitting machine, and the filament is bent in a loop shape and pulled. For this reason, the generation of fluff involves the degree of bending of the filament and the tensile force. On the other hand, in FIG. 6, in the case of a wire exceeding 0.75 mm in which the influence of the wire diameter on the hooking strength of the filament is small, the degree of bending of the filament is small, and the cutting force of the filament is smaller than the bending force of the filament. The effect is greater. For wires with a diameter of less than 0.5 mm,
The degree of bending of the filament increases, and the bending of the filament has a greater effect on the cutting of the filament than on the tensile force.

In this regard, in the case of a wire having a diameter of 0.5 to 0.75 mm,
Since the degree of bending of the filament is moderate, and both the bending of the filament and the tensile force affect the cutting of the filament, there is a good correlation between the hooking strength of the filament and the generation of fluff. However, as shown in FIG.
The influence of the diameter of the wire on the tension of the filament measured using a wire of 0.75 mm is extremely large. For this reason, the hooking strength of the filament measured using a wire having an intermediate diameter of 0.5 to 0.75 mm has a large measurement error. Therefore, in the present invention, the measurement error is relatively small, and the correlation with fluff or the like generated at the time of weaving or the like is 0.5 mm in diameter.
Was used to measure the value of the hooking strength of the filament. The knot strength of the yarn was measured by the method shown in FIG. In FIG. 5, one end of a measurement yarn 70 having one knot portion (knot) 72 formed in the middle is fixed, and the other end is gripped by the clamp 60. Then, the clamp 60 is pulled in the direction of arrow B, and the yarn endurance is reduced. Measure the load. The “knot strength of yarn” in the present invention is:
Measured on a measurement yarn consisting of 1000 filaments previously bundled with a sizing agent (eg, epoxy resin).

In such a yarn of the present invention, at least a part of the filaments constituting the filament group is
It cross-sectional shape is a flat filament twisted portion is formed and spaced longitudinally flat shape, Ru can be improved textile properties, such as knot strength of the hooking strength and yarn filaments. Such a flat filament is shown in FIG.
As shown in FIG. 1C, in the cross section of the flat filament A, a long side 10 having a maximum straight line length connecting two points located on the periphery of the cross section and a right angle to the long side 10 There is a short side 20 where the straight line length across the cross section is maximum. If the long side 10 and the short side 20 are present in the cross section of the flat filament A, the cross section is elliptical (FIG. 1 (A)), magatama (FIG. 1 (B)), raindrop [ 1 (C)].

Further, in the yarn, as shown in FIG.
2 ... may be mixed. In the yarn in which the flat filament A and the round cross-section filament 52 shown in FIG. 2 are mixed, the higher the mixing ratio of the flat filament A, the more the physical properties such as the hooking strength of the filament and the flexibility tend to be improved. The mixing ratio of the filament A is 10% or more,
In particular, by setting the content to 30% or more, it is possible to obtain a yarn in which the weaving and knitting properties are sufficiently improved. Here, in the flat filament A mixed in the yarn, when the length of the long side 10 is x and the short side 20 is y, the long side 10 and the short side 2
The larger the ratio to 0 (x / y: flatness), the more the flexibility of the yarn can be improved, but the strength such as the tensile strength of the yarn tends to decrease. For this reason, adjusting the flatness (x / y) of the flat filament A to 1.1 to 3.0, particularly 1.2 to 2.5, can improve the flexibility and the like of the yarn while maintaining the strength of the yarn. Can be improved.

Further, in the longitudinal direction of the flat filament A shown in FIGS. 1 (A) to 1 (C) and FIG. 2, a predetermined interval is provided as shown in FIGS. 3 (A) and 3 (B). There is a twisted part. In each of the flat filaments A shown in FIGS. 3A and 3B, the twisted portions 40 and the non-twisted portions 30 are alternately arranged. Flat filament A in FIG. 3 (A)
In the flat filament A of FIG. 3B, the torsion portion 40 is rotated by about 180 ° with respect to the non-twisted portion 30. FIGS. 3A and 3B show a state in which such a twisted portion 40 exists in the longitudinal direction of one flat filament A.
Or one of the states may be almost present, or both states may exist together. The extent of the twisted portion 40 varies depending on the fiber diameter of the flat filament A, etc., but it is preferable that one twisted portion 40 exists every 10 to 500 μm from the viewpoint of the yarn strength and the like.

The yarn of the present invention is a spinning dope obtained by concentrating an aqueous solution obtained by adding a partially saponified polyvinyl alcohol (PVA) to a precursor whose main components are a silica sol component and a basic aluminum chloride component to a predetermined concentration. And FIG.
The spinning is performed by using the spinning apparatus shown in (1). In FIG. 7, a plurality of spinning packs 1, 1,... This spinning pack 1,
A spinneret provided with a plurality of ejection holes is provided on each lower surface of 1... As described later. From these discharge holes, the spinning solution is simultaneously discharged into the spinning cylinder 2 to obtain discharge yarns 7, 7,. Each of the discharge filaments constituting the obtained discharge yarn travels in the spinning tube 2 while being countercurrently contacted with a heating fluid such as a heating air flow while being desolvated, and converged and tied by the converging pin 9. Then, it is wound up by the winding device 11. The winding speed at this time is arbitrarily determined in relation to productivity, but if the winding speed is set to 100 m / min or less, the discharged yarn 7 can be sufficiently dried. The heating fluid is heated by a heating unit 13 provided at a lower portion of the spinning tube 2, and then flows through heating fluid supply holes 15, 15. Supplied within.

The spinning solution supplied to each of the plurality of spinning packs 1, 1,... Is supplied from the stock solution hopper to each of the spinning packs 1 via the metering pump 3 and the filter 5, as shown in FIG. It is sent. In the supply pipe 18 for feeding the spinning solution and the branch pipe 19 for supplying the spinning solution to each spin pack 1, the length of the pipe from the raw material hopper to each spin pack 1 is made as equal as possible, and / or Alternatively, by branching a branch pipe 19 from a storage part (chamber) provided near the end of the supply pipe 18 to each of the spinning packs 1, the supply pressure of the spinning solution flowing into each of the spinning packs 1 can be increased as much as possible. The same pressure can be used, and the obtained filaments can be equalized. In such a spinning apparatus shown in FIG. 7, each of the spinning packs 1 to which each of the divided spinnerets is mounted is arranged such that the discharge surfaces of the respective spinnerets of the spinning packs 1... Are in the same horizontal plane. .. Are divided into a plurality of filament groups and discharged, and a part of the heating fluid that has risen in the heating cylinder 2 passes through the gap. Then, it is discharged out of the spinning cylinder 2.

In this spinning apparatus, the discharged yarn can be divided into as small groups as possible and discharged, and a heating fluid can be supplied so as to wrap each discharged yarn. Therefore, each of the discharge filaments constituting the discharge yarn and the heating fluid can be brought into sufficient contact. As described above, in the spinning apparatus shown in FIG. 7, since the divided spinneret is used, the total number of discharge holes can be set to 600 or more. For this reason, a yarn composed of 600 or more filaments can be obtained without tying a plurality of yarns, and a yarn tying step of supplying the yarn to a weaving step or the like can be omitted. In addition, although the yarn which has been plied is liable to cause a yarn crack, the yarn obtained by using the spinning device shown in FIG.
Yarn cracking is unlikely to occur. FIG. 9 shows the spin pack 1 used in FIG. FIG. 9 is a longitudinal sectional view of the spinning pack 1, and a spinneret 23 having a rectangular planar shape obtained by processing a stainless steel plate or the like is provided on the lower surface of the rectangular house 21 of the spinning pack 1. A plurality of discharge holes 25 are formed in the spinneret 23 in a lattice shape.

As shown in FIG. 10A, the discharge hole 25 is formed at the lower end of the undiluted solution introduction hole 33 at the tip of a projection 35 discharged from the lower surface of the spinneret 23. According to the discharge hole 25, wetting of the spinning solution at the outlet of the discharge hole can be reduced, separation of the discharge hole of the spinning solution can be improved, and the spinning solution can be stabilized in the projection 35 in combination with the rectifying effect of the spinning solution. Spinning can be performed. On the side surface of the rectangular house 21, a stock solution supply hole 2 for connecting a stock solution supply pipe 19 for feeding a stock solution for spinning into the rectangular house 21 near the upper surface of the spinneret 23.
7 are drilled. When the spinning solution is supplied to the spinning pack 1 shown in FIG. 10A so that the air layer 31 is formed on the upper surface of the spinning solution layer 29 in the rectangular house 21, a uniform thickness is formed on the upper surface of the spinneret 23. The spinning dope layer 29 is formed, and the spinning dope can be uniformly discharged from each of the discharge holes 25. Here, when the vertical cross-sectional shape of the source liquid introduction hole 33 formed in the spinneret 23 is tapered as shown in FIG. 10B, the flow of the spinning source liquid in the source liquid introduction hole 33 is further increased. It can approach laminar flow.

When spinning is performed by using the spinning apparatus shown in FIG. 7, the discharged filament discharged from each of the projecting holes 25 is rapidly dried to obtain a yarn composed of a filament having a high hooking strength. It is important. As described above, for rapid drying of the discharge filament, each of the discharge filaments is brought into sufficient contact with the heating and drying fluid, and dry air having a dew point temperature of 4 ° C. or less is supplied as the heating and drying fluid to the spinning cylinder 2. It is necessary to supply from the holes 15, 15... Such low humidity dry air is
It can be obtained by compressing high-humidity air and dehumidifying it with a freezing dehumidifier or the like, and then adsorbing water vapor with an adsorbent such as activated carbon, zeolite or activated alumina, if necessary. By firing the spun yarn thus obtained under known conditions, a ceramic yarn can be obtained. In the spinning, the lower the humidity of the fluid supplied to the spinning cylinder 2 and the higher the temperature of the fluid, the flatter the cross-sectional shape and the longer the longitudinal direction in the filaments constituting the obtained yarn. There is a tendency that the mixing ratio of the flat filament having the twisted portion is increased.

FIGS. 7 to 10B described so far.
In the above, an example is shown in which the spinning packs 1, 1,... To which each of the divided spinnerets is mounted are arranged via a predetermined gap so that the lower surfaces of the spinnerets are in the same horizontal plane. As shown in FIGS. 11A and 11B, a plurality of discharge holes are formed in the same spinneret, and a gap is provided in which a part of the heating fluid passes and is discharged out of the spinning cylinder 2. Is also good. FIG. 11A shows a state in which a discharge hole 25 is formed concentrically in a circular spinneret 23 and a plurality of circular gaps 50 through which a part of the heating fluid passes are formed at the center of the spinneret 23 and its periphery. It is provided in. FIG. 11B shows a rectangular spinneret 23 in which discharge holes 25 are formed in a grid pattern and a plurality of slit-shaped gaps 50 through which a part of the heating fluid passes.
Is provided in parallel with the spinneret 23.

[0021]

The present invention will be described in more detail by way of examples. Example 1 (1) Production of ceramic fiber yarn 17.3 kg of an aqueous solution of basic aluminum chloride containing 13.2% by weight of aluminum (Al) ion and 12.6% by weight of chlorine (Cl) ion, and 20 of SiO ₂ 8.4 kg of colloidal silica containing 30 wt%, 30 g of phosphoric acid, and 15 kg of a 10 wt% aqueous solution of partially saponified polyvinyl alcohol (PVA) were mixed and concentrated under reduced pressure to obtain a 550 poise (20 ° C.) spinning stock solution. . This spinning solution was spun using the spinning apparatus shown in FIG. The spin pack used in this spinning device is 4
Each of the spin packs is a spin pack shown in FIG. 9 equipped with a spinneret shown in FIG. This spinneret has two discharge nozzles each having a hole diameter and a hole length of 0.2 mm.
There were 50 holes. During such dry spinning, the spinning solution is discharged from each of the discharge nozzles of the spinneret in an atmosphere in which the temperature in the spinning cylinder near the spinneret is maintained at 80 ° C., and the discharged discharge filaments are converged. While being in contact with dry air whose dew point was adjusted to 2 ° C. and blown from the lower part of the spinning tube 2, the fiber was taken off at a take-up speed of 30 m / min to obtain a precursor fiber composed of 1,000 filaments. Next, the precursor fiber was baked at 1200 ° C. for 30 minutes to obtain a yarn composed of 1,000 transparent filaments having an alumina component of 72% by weight and a silica component of 28% by weight.

(2) Characteristics of Ceramic Fiber Yarn Cross-sectional Shape of Yarn, Shape and Strength of Constituent Filament When an arbitrary cross section of the obtained yarn was observed with an optical microscope, about 80% of the constituent filaments were flat filaments. The average long side length (x) was about 11 μm and the average short side length (y) was about 7 μm [average flatness (x / y) of flat single fiber = 1.6]. Further, in the longitudinal direction of each of the flat filaments, as shown in FIG.
There was a twist that was rotated 90 ° every 30-60 μm. Further, the strength of 20 arbitrarily sampled flat filaments was measured, and the average tensile strength was 2.3 GPa and the average tensile modulus was 200 GPa. Measurement of Hook Strength of Filament The hook strength of 20 filaments was measured by a method shown in FIG. 4 using a stainless steel wire having a circular cross section and a diameter of 0.5 mm. The filament for measurement was arbitrarily collected from the obtained yarn. The average of the measured values was 3.7 × 10 ⁻² N. Other conditions for measuring the hooking strength are shown below. Measurement filament length 25 mm (length from gripping member 64 to hook of wire 22) Pulling speed 5 mm / min Knot strength of yarn 1000 filaments were collected from an arbitrary portion of the aligned yarn by the method shown in FIG. The knot strength was measured for 20 measurement yarns. The average of the measured values was 314 dyn / TEX. Other conditions for measuring the knot strength of the yarn are shown below. Test length: 75 mm [Length from clamp 60 to fixed end of measurement yarn 70 (length indicated by distance H in FIG. 5)] Knot state: Approximately central portion of test length is tied once Pulling speed: 20 mm / min The measuring yarn is provided with a sizing agent composed of a bisphenol A type epoxy agent in an amount of 3% by weight with respect to the measuring yarn, and is bundled.

(3) Knitting The obtained yarn was knitted by using a knitting machine having a rotation speed of 60 Hz. The tube knitting could be performed favorably without causing any yarn breakage during the tube knitting, and the obtained tube knit did not have any fluff and had a good appearance.

Example 2 The yarn obtained in Example 1 was heated at 1400 ° C. in air.
The heat treatment was carried out while changing the treatment time, and the changes in the crystal structure and the average crystal grain size were measured by X-ray diffraction, and the tensile strength of the yarn was also measured. The results are shown in Table 1.
At this time, as a control, in Example 1, 13.34 kg of an aqueous solution of basic aluminum chloride containing 13.5% by weight of aluminum (Al) ions and 12.8% by weight of chlorine (Cl) ions, SiO ₂ 3 kg of colloidal silica containing 20% by weight of a partially saponified polyvinyl alcohol (PVA)
12 kg of a 10% by weight aqueous solution was mixed and concentrated under reduced pressure, and a spinning stock solution of 750 poise (20 ° C.) was used.
The yarn obtained in the same manner as in Example 1 was used (the composition of the fired yarn: alumina component / silica component = 85).
/ 15). Similarly, the yarn of the control example was subjected to heat treatment in air at 1400 ° C. while changing the treatment time, and the transition of the crystal structure and the average crystal grain size was measured, and the tensile strength of the yarn was also measured. The results are shown in Table 1.

[0025]

[Table 1]

As is clear from Table 1, by subjecting the yarn of Example 1 to a heat treatment at 1400 ° C. for 30 minutes, the crystals forming the yarn shift to 100 % mullite crystals. On the other hand, in the case of the control yarn, 1400 ° C., 3
Even after the heat treatment for 0 minutes, the proportion of the mullite crystal determined from the intensity of the X-ray diffraction peak is only about 54%, and about 46% of the transition alumina crystal remains. For this reason, when the heat treatment time at 1400 ° C. elapses for 2 hours, the transition alumina crystal shifts to α-alumina crystal, and when the heat treatment is continued, the average crystal grain size sharply increases, and the tensile strength and flexibility of the yarn are increased. Decreases rapidly. On the other hand, in the yarn of Example 1, the growth rate of the average crystal grain size during the heat treatment at 1400 ° C. was slower than that of the yarn of the control example. Is still flexible and can maintain a strength of 0.6 GPa.

[0027]

Comparative Example 1 The procedure of Example 1 was repeated except that, while spinning, the inside temperature of the spinning cylinder near the spinneret was maintained at 60 ° C., and dry air adjusted to a dew point of 9 ° C. was blown into the spinning cylinder. A yarn was obtained in the same manner as in Example 1. The cross-sectional shape of the filaments constituting this yarn was substantially circular, and there was substantially no twist in the longitudinal direction of the filament. The resulting yarn had an average tensile strength of 1.8 GPa and an average tensile modulus of elasticity of 180 GPa. This yarn has a crystal structure mainly composed of transition alumina crystals.
A transition to a mullite crystal structure occurs by baking at 00 ° C. for 30 minutes. However, the hook strength of the filaments constituting the obtained yarn is 1.8 × 10 ^-2 N and 2.5 × 10 ^-2 N
Was less than. Further, the knot strength was 178 dyn / TEX. Next, when the yarn was knitted by a knitting machine, yarn breakage occurred frequently during knitting, and the knitting was stopped.

[0029]

According to the present invention, a ceramic fiber yarn having excellent heat resistance can be obtained by spinning a spinning dope containing a basic aluminum chloride component having good spinnability. Productivity can be improved. In addition, the yarn of the present invention can provide a heat-resistant fabric having excellent passability in a weaving step or a knitting step and having a good appearance.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a cross-sectional shape of a flat filament constituting a yarn according to one embodiment of the present invention.

FIG. 2 is a partial cross-sectional view showing a part of a cross section of a yarn according to one embodiment of the present invention.

FIG. 3 is a partial front view showing a shape in a longitudinal direction of a flat filament constituting a yarn according to an embodiment of the present invention.

FIG. 4 is an explanatory diagram for explaining a method for measuring the hooking strength of a filament employed in the present invention.

FIG. 5 is an explanatory diagram for explaining a method of measuring the knot strength of a yarn employed in the present invention.

FIG. 6 is a graph showing the relationship between the hooking strength of a filament and the diameter of a wire used.

FIG. 7 is a schematic view showing an outline of a spinning apparatus for producing yarn according to one embodiment of the present invention.

FIG. 8 is an explanatory diagram illustrating a path for supplying a spinning source liquid to each of the spinning packs illustrated in FIG. 7;

FIG. 9 is a longitudinal sectional view of the spin pack shown in FIGS. 7 and 8;

FIG. 10 is a sectional view of a discharge hole provided in a spinneret.

FIG. 11 is a plan view showing another embodiment of the spinneret.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Long axis 20 Short axis 30 Non-twist part 40 Twist part 52 Filament with round cross section A Flat filament

Continuation of the front page (72) Inventor Nao Kitahara 3865-3, Minamiminowa-mura, Kamiina-gun, Nagano Prefecture Inside Daimei Chemical Industry Co., Ltd. (56) References JP-B-61-32405 (JP, B1) (58) Fields investigated Int.Cl. ⁷ , DB name) D01F 9/08

Claims (5)

(57) [Claims] 1. A spinning dope containing a silica sol component and a basic aluminum chloride component is spun and baked to obtain an alumina component of 67 to 75% by weight and a silica component of 25 to 75% by weight.
33 consists filament group constituted by wt% and filaments formed by, and the crystal structure of the filament is a ceramic fiber yarn is a polycrystalline structure consisting mainly transition alumina crystal, at least constituting the filament group Some filaments
Have a flat cross-sectional shape and are spaced in the longitudinal direction.
A flat filament iterator twisted portion is formed, any 20 filaments constituting the yarn Nitsu
There, the average value of the hooking strength measured by using a wire of 0.5mm diameter is Ru Ah at ^{3.7 × 10 -2 ~ 2.5 × 10} -2 N
Together, when the heat treatment was performed pre-Symbol yarns 30 minutes at 1400 ° C., ceramic fiber yarn, characterized in that the transition in the crystal structure gum light crystal structure of filaments constituting the yarn after the heat treatment. 2. The yarn has a knot strength of 314 to 200 dyn /
The ceramic fiber yarn according to claim 1, which is TEX. 3. A flat filament in a filament group.
The ceramic fiber yarn according to claim 1 , wherein the mixing ratio of the ceramic fiber is 10% or more . 4. A cross section of a flat filament,
The maximum straight line length between two points located on the periphery of the cross section
The length (x) of the long side that is
Length of the short side where the straight line length across the cross section is the maximum (y)
The ceramic fiber yarn according to claim 1 , wherein the ratio (x / y) is 1.1 to 3. 5. The flat filament has a twisted portion of 10-5.
Ceramic fiber yarn according to claim 1, wherein that exists for each 00Myuemu.