JP7111620B2 - Method for producing continuous alumina fiber sheet and continuous alumina fiber sheet - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing an alumina fiber continuous sheet and an alumina fiber continuous sheet.

As one method for producing an aluminous fiber continuous sheet, a spinning dope containing an aluminum compound is spun to form an aluminous fiber precursor, and the precursor fibers are piled up on an endless belt to form a precursor continuous sheet, A method of forming a continuous alumina sheet by firing is known. Further, in order to further improve the mechanical strength of the continuous alumina fiber sheet, a method is known in which the precursor sheet is subjected to needling treatment and then sintered to produce an alumina fiber sheet.

The aluminous fiber continuous sheet produced by the above method is widely used, for example, as a heat insulating material for heating furnaces, taking advantage of its excellent fire resistance and heat insulating properties. In the field of automobile parts, the alumina fiber continuous sheet manufactured by the above method is installed between a ceramic honeycomb carrier and its housing case used as exhaust gas purification catalytic converters and diesel engine particulate filters. It is used as a holding material (also called a gripping material). The holding member serves to prevent the honeycomb carrier from hitting the inner wall of the housing case and being damaged due to vibration, impact, or the like. In particular, in recent years, the environmental performance of automobiles has been emphasized. On the other hand, it is required to maintain moderate elasticity for a long period of time. Further, studies have been made to increase the holding power by increasing the strength of the fibers (Patent Document 1).

However, even if the strength of the fiber itself is sufficient, if the surface mass (mass per unit area) of the holding material installed in the catalytic converter varies, the holding force (pressure) will increase in areas where the surface mass is high. If it becomes too high, there is a risk that the honeycomb carrier will break. On the other hand, in a portion with a low surface mass, the honeycomb carrier may be damaged because the impact cannot be alleviated due to insufficient holding force. For this reason, it is preferable that the holding force of the holding material has little variation.
In order to solve this problem, there is a known method of adjusting the position of a spinning machine so as to equalize the variation in the surface mass when the precursor fibers are deposited on the cotton collecting conveyor (Patent Document 2). . Alternatively, there is known a method of folding thin alumina fiber sheets stacked on a cotton collecting conveyor using a folding machine or the like (Patent Document 3).

JP-A-7-286514 JP 2006-152474 A JP-A-2000-80547

An object of the present invention is to provide a method for producing a continuous alumina fiber sheet having a uniform surface mass and to provide a continuous alumina fiber sheet capable of reducing variations in holding force when used as a holding material. .

The present inventor conducted various studies to solve the above problems, and as a result, the variation in the surface mass of the alumina fiber continuous sheet was found to be caused by the lamination of the precursor continuous sheet when the alumina fiber precursor was deposited on the stacking device. It has been found that the surface layer portion of the continuous precursor sheet is caused by the variation, and the portion that has a particularly large effect on the variation in the surface mass is the surface layer portion of the precursor continuous sheet. Therefore, it was clarified that it is possible to produce an aluminous fiber continuous sheet with little variation in surface mass by removing the surface layer of the precursor continuous sheet.
Also, the holding power of the carrier is embodied by the coefficient of friction of the holding material. Therefore, in order to obtain a high holding force, the coefficient of friction should be high. However, if there is a large variation in the coefficient of friction, the holding force will also vary, and there is concern that the problems described above will occur. That is, it was found that the variation in the holding force of the holding material is caused by the variation in the coefficient of friction of the continuous alumina fiber sheet.

In order to solve the above problems, the present invention employs the following means.
(1) (I) a step of spinning a spinning dope containing an aluminum compound and a silicon compound as main components to obtain an aluminous fiber precursor; (III) slicing the surface layer of the continuous precursor sheet with a slicing machine to make it smooth; (IV) subjecting the continuous precursor sheet to entangling treatment by needling; and (V) the above A method for producing an aluminous fiber continuous sheet through a step of sintering a precursor continuous sheet.
(2) The slicing machine is a slicing machine having a mechanism in which two upper and lower cutting blades having comb-shaped blades are reciprocatingly slid to the left and right to cut by sliding contact between the comb-shaped blades. The method for producing an aluminous fiber continuous sheet according to (1) above.
(3) The aluminous fiber according to (1) or (2) above, wherein the ratio of the surface layer portion to be sliced and removed in the step (III) is 5 to 30% by mass with respect to the total weight of the precursor continuous sheet. A method for producing a continuous sheet.
(4) The method for producing a continuous alumina fiber sheet according to any one of (1) to (3) above, wherein the average surface mass of the continuous alumina fiber sheet is 300 to 3000 g/m ² .
(5) The method for producing a continuous alumina fiber sheet according to any one of (1) to (4) above, wherein the surface mass variation of the continuous alumina fiber sheet is 10% or less.
(6) The method for producing a continuous alumina fiber sheet according to (5) above, wherein the surface mass variation of the continuous alumina fiber sheet is 5% or less.
(7) An alumina fiber continuous sheet having a friction coefficient variation of 10% or less on at least one surface.
(8) The continuous aluminous fiber sheet according to (7) above, which has an average surface mass of 1350 g/ cm ³ or more and a variation in surface mass of less than 10%.

According to the present invention, it is possible to manufacture an alumina fiber continuous sheet having a uniform surface mass by a simpler method than conventionally, and to reduce variations in holding force when used as a holding material. An aluminous fiber continuous sheet can be provided.

FIG. 4 is an explanatory diagram of a step of smoothing the surface layer of the precursor continuous sheet according to one embodiment of the present invention; It is an explanatory view (top view) showing an example of a slicer concerning one embodiment of the present invention. FIG. 4 is an explanatory diagram of an angle formed between a blade of a slicing machine and a precursor continuous sheet according to one embodiment of the present invention; FIG. 2 is an explanatory diagram of a method for measuring the coefficient of friction of a sample obtained from the continuous aluminous fiber sheet.

The present invention will be described in detail below.

The method for producing an aluminous fiber continuous sheet of the present invention includes (I) a step of spinning a spinning dope containing an aluminum compound and a silicon compound as main components to obtain an aluminous fiber precursor, and (II) the aluminous fiber precursor. (III) slicing the surface layer of the precursor continuous sheet with a slicing machine to make it smooth, (IV) entangling the precursor continuous sheet by needling and (V) a step of firing the precursor continuous sheet.

A known method can be applied to the step of spinning the spinning dope containing the aluminum compound and the silicon compound of the present invention as main components to obtain an aluminous fiber precursor, and the production method is not particularly limited.
The aluminum compound and silicon compound, which are the main components of the spinning dope, are not particularly limited. For example, aluminum compounds such as aluminum oxychloride, alumina sol, aluminum nitrate, aluminum isopropylate, aluminum acetate, and aluminum alkoxide are suitable. Silica sol, polysiloxane, colloidal silica, water-soluble silicone, silicon alkoxide and the like are preferably used as the silicon compound.
By mixing these compounds in the ratio of the alumina component and the silica component of the desired chemical composition, it is possible to adjust the chemical composition of the aluminous fiber continuous sheet. The chemical composition of the continuous alumina fiber sheet is not particularly limited, but from the standpoint of heat resistance, it is preferable to include 72 to 97% by mass of alumina component in terms of Al ₂ O ₃ and 28 to 3% by mass of silica component in terms of SiO ₂ . preferable.
Furthermore, for the purpose of improving spinnability, spinning aids such as polyvinyl alcohol, polyethylene oxide, polyethylene glycol, glucose, methylcellulose, and starch can be blended. Adjustment by vacuum concentration is also possible.

As a method for processing the spinning dope into the aluminous fiber precursor, for example, there is a method of rapidly drying the spinning dope while extruding it into the air through the pores of a die. There are no particular restrictions on the structure of the die and the arrangement of pores, the discharge amount and pressure of the spinning dope, and the temperature, pressure, gas component, humidity, and presence or absence of airflow in the space where the dope is extruded. The mold dies may be of either fixed or movable construction.
As a more specific example, a spinning stock solution is supplied into a hollow disk rotating at a peripheral speed of 5 m/s or more and 100 m/s or less, and a plurality of hollow disks having a diameter of 0.1 mm or more and 1.3 mm or less are provided on the circumferential surface of the disk. A fiber precursor can be obtained by radially (filamentally) ejecting the spinning dope from the pores of the fiber and rapidly drying it while contacting it with a high-speed air stream.

The method of stacking the aluminous fiber precursors on a stacking device to form a continuous precursor sheet is not particularly limited, but a method of stacking them on a belt conveyor or net conveyor and forming them into a continuous sheet is preferably used.

In the present invention, as shown in FIG. 1, the surface layer of the precursor continuous sheet 20 accumulated on the transport net conveyor 21 is sliced by the slicer 1 and smoothed. The transport speed of the transport net conveyor 21 (the transport speed of the precursor continuous sheet 20) during slicing is preferably 30 to 400 mm/min, more preferably 30 to 200 mm/min, and 60 to 100 mm. /min is more preferred. By setting the conveying speed to 30 to 400 mm/min, it is possible to further reduce variations in the surface mass.

The slicing machine that slices the surface layer of the precursor continuous sheet includes a band saw slicing machine that rotates a band-shaped blade at high speed, a slicing machine that has a mechanism for slicing by reciprocating the blade left and right, and a slicing machine that rotates a circular blade to cut. It is possible to use a roll cutter slicer or the like that performs Of these, a slicing machine (hereinafter referred to as "upper and lower 2 cutting blades") has a mechanism in which two upper and lower cutting blades having comb-shaped blades are reciprocally slid to the left and right, and cutting is performed by sliding contact between the comb-shaped blades. A single-blade reciprocating slicing machine") is most preferable in terms of reducing variations in surface mass.
FIG. 2 schematically shows an example (top view) of a reciprocating slicing machine with upper and lower two blades. This slicing machine reciprocates and slides an upper cutting blade 101 and/or a lower cutting blade 102 to the left and right (cutting blade sliding direction indicated by an arrow in the drawing) with the power of a blade drive motor 11, and each cutting blade Cutting is performed by sliding contact between comb-shaped blades.

Furthermore, the angle formed by the blade of the slicing machine and the precursor continuous sheet is preferably 0 to 10°. Here, the angle formed by the blade of the slicing machine and the continuous precursor sheet means the angle θ (corresponding to reference numeral 30) in FIG. The smaller angle between the two. By slicing within the above angle range, the surface of the precursor continuous sheet can be maintained in a smooth state, and an alumina fiber continuous sheet with good surface properties can be obtained.

The slice amount of the surface layer portion is preferably 5 to 30% by mass of the whole precursor continuous sheet. More preferably 10 to 22% by mass, still more preferably 10 to 17% by mass. If the amount of slicing is small, there is a risk that the surface layer portion that causes variations in surface mass cannot be sufficiently removed, and if the amount of slicing is excessively increased, the productivity decreases.

The surface mass value of the aluminous fiber continuous sheet can be adjusted by adjusting the production amount of the precursor fiber, the conveying speed of the stacking device, and the amount of slicing.
The average surface mass of the continuous aluminous fiber sheet is preferably 300 to 3000 g/m ² .

By subjecting the precursor continuous sheet to entangling treatment by needling, it is possible to obtain an alumina fiber continuous sheet having excellent mechanical strength. Needling strokes are preferably 20 to 50 strokes/cm ² . If the number of strokes is less than this range, sufficient mechanical strength may not be obtained due to insufficient needling.

In the step of firing the precursor continuous sheet, a continuous furnace such as a roller hearth kiln is preferably used. The maximum temperature of the continuous heating furnace is preferably 1000° C. or higher and 1300° C. or lower, preferably 1150° C. or higher and 1250° C. or lower. Further, the structure of the heating furnace is not limited, but for example, as the first stage, at the stage where the precursor continuous sheet has been subjected to the needling treatment, it is heated from room temperature to 1000° C. or lower, preferably 850° C. or lower. A degreasing process is performed to discharge moisture and acidic components remaining in the body continuous sheet, as well as organic matter, which is the decomposition product of the tackifier, from the furnace. A staged heating furnace is preferably used for carrying out the crystallization step of partially crystallizing the inorganic compound.

The heating furnace for the degreasing step preferably has a structure that allows the introduction of hot air and the discharge of volatile components, and the heating rate is preferably 6° C./min or less, more preferably 4° C./min or less. If the heating rate is too high, volume shrinkage occurs without sufficient volatilization of moisture and acidic components, and decomposition of the tackifier, resulting in a fiber with many defects, which may make it difficult to demonstrate its properties. .

The heating furnace for the crystallization step preferably has a structure in which a heating element is resistance-heated. With this structure, it is possible to precisely control the maximum firing temperature and control the crystal form of the inorganic compound in the aluminous fiber aggregate.
In the crystallization step in the present invention, firing may be performed under normal conditions (temperature, holding time) that cause crystallization of the inorganic fiber source. In order to achieve the above, the maximum firing temperature is preferably 1000 ° C. or more and 1300 ° C. or less, and the heating time is preferably 5 minutes or more and 120 minutes or less, and more preferably 5 minutes or more and 60 minutes or less. preferable. If the sintering temperature is lower than 1000° C., the heat resistance of the aluminous fiber is lowered, and there is a possibility that it may not be suitable for the use temperature of the gripping material of the exhaust gas purifying device. On the other hand, if it is higher than 1300° C., the crystallization of the aluminous fibers such as mullite progresses excessively, which may reduce the fiber strength. If the holding time at the maximum temperature is shorter than 5 minutes, the crystallization may not proceed sufficiently, resulting in unevenness in the fine structure. Crystal growth may proceed excessively. In both cases, the fiber strength is lowered, so that the shape restorability of the continuous alumina fiber sheet is lowered.

The continuous alumina fiber sheet of the present invention produced through these steps is characterized by small variation in surface weight, and the variation in surface weight is preferably 10% or less, more preferably 5% or less. .

The continuous alumina fiber sheet of the present invention has a coefficient of friction variation of 10% or less on at least one surface.
When the coefficient of friction of at least one surface of the continuous alumina fiber sheet has a variation of more than 10%, the holding material produced using the continuous alumina fiber sheet has a very high holding power when installed in the catalytic converter. Some parts and very low parts may occur. In addition, there is a risk that the honeycomb carrier will break at the portion where the holding force is very high, and the impact cannot be mitigated at the portion where the holding force is very low due to insufficient holding force. may be damaged. From the viewpoint of reducing the variation in holding power, the variation in the coefficient of friction on at least one surface of the continuous alumina fiber sheet is preferably 7% or less, more preferably 5% or less.

The coefficient of friction can be measured according to the method of Examples described later. The variation in friction coefficient is the coefficient of variation (%) of friction coefficient in 100 samples (=standard deviation/average value×100).

In addition, in the aluminous fiber molded article described in Patent Document 2, since the surface layer of the accumulated precursor fiber is not sliced by a slicing machine to make it smooth, at least one of the aluminous fiber continuous sheets It is not possible to reduce the variation in the coefficient of friction of the surfaces.
On the other hand, in the continuous alumina fiber sheet of the present invention, the surface layer of the precursor continuous sheet of the alumina fiber precursor is sliced and smoothed by a slicing machine, so the friction coefficient of at least one surface of the continuous alumina fiber sheet variation can be reduced. In particular, by setting the slice amount to 5% by mass or more, the variation in the coefficient of friction can be reduced to 10% or less.

That is, the aluminous fiber continuous sheet of the present invention, which has a friction coefficient variation of 10% or less on at least one surface, is prepared by spinning a spinning stock solution containing an aluminum compound and a silicon compound as main components (I) to produce an aluminous fiber precursor. (II) stacking the aluminous fiber precursor in a stacking device to form a precursor continuous sheet; (III) slicing the surface layer of the precursor continuous sheet with a slicing machine to make it smooth. , (IV) a step of subjecting the precursor continuous sheet to entangling treatment by needling, and (V) a step of firing the precursor continuous sheet, wherein the precursor The aluminous fiber continuous sheet has a slice amount of 5% by mass or more when the surface layer of the continuous sheet is sliced by a slicing machine.

The continuous alumina fiber sheet of the present invention preferably has an average surface mass of 1350 g/ cm ³ or more and a variation in surface mass of less than 10%.

In the alumina fiber continuous sheet of the present invention, the surface layer of the precursor continuous sheet of the alumina fiber precursor is sliced and smoothed by a slicing machine, so that the average surface mass of the alumina fiber continuous sheet is 1350 g/ cm . Even when it is ³ or more, the variation in surface mass of the continuous aluminous fiber sheet can be reduced to less than 10%. When the average value of the surface mass of the continuous alumina fiber sheet is 1350 g/ cm ³ or more, the variation in the surface mass of the continuous alumina fiber sheet is more preferably 9% or less, further preferably 7% or less. , more preferably 5% or less.
In addition, from the viewpoint that the effect of reducing the variation in the surface mass of the present invention becomes more remarkable, the average value of the surface mass of the continuous alumina fiber sheet is more preferably 1400 g/ cm ³ or more, and more preferably It is 1450 g/ cm ³ or more, more preferably 1500 g/ cm ³ or more.
In addition, in the aluminous fiber molded article described in Patent Document 2, since the surface layer of the accumulated precursor fiber is not sliced by a slicing machine to make it smooth, the surface mass of the alumina fiber molded article is reduced. Even if the average value is less than 1350 g/ cm ³ , the variation in surface mass of the alumina fiber molded body cannot be less than 10%. Furthermore, as the average value of the surface mass of the alumina fiber molded body increases, the variation in the surface mass of the alumina fiber molded body also increases. If the average surface mass of the body is 1350 g/ cm ³ or more, it becomes more difficult to keep the variation in the surface mass of the alumina fiber molded body to less than 10%.
In addition, the average value of the surface mass and the variation in the surface mass of the continuous aluminous fiber sheet can be measured according to the method of Examples described later.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

"Example 1"
An aqueous aluminum oxychloride solution having an alumina solid content concentration of 20.0% by mass and colloidal silica having a silica concentration of 20.0% by mass are mixed so that the alumina component is 73% by mass and the silica component is 27% by mass. Furthermore, after mixing a partially saponified polyvinyl alcohol aqueous solution with a degree of polymerization of 1700 and a solid content concentration of 10% by mass so that the total solid content of the alumina component and the silica component is 8%, dehydration concentration is performed under reduced pressure, A spinning dope having a viscosity of 2000 mPa·s was prepared.
This spinning stock solution is passed through 300 holes with a diameter of 0.2 mmφ that are evenly spaced on the circumferential surface of a hollow disk with a diameter of 350 mmφ, and the stock solution is poured into the disk so that the discharge rate per hole is 25 mL / h. The spinning dope was radially ejected from the holes by rotating the disk at a peripheral speed of 47.6 m/sec.
The undiluted solution spouted out from the pores was dried while floating and falling in hot air to obtain an aluminous fiber precursor. This aluminous fiber precursor was accumulated at a speed of 70 mm/min on a net conveyor having a width of 1 m and was sucked from the bottom to form a precursor continuous sheet.

After removing 15% of the mass of the precursor continuous sheet from the surface layer portion of the precursor continuous sheet with an upper and lower two-blade reciprocating slicing machine, needling treatment was performed at 30 strokes/cm ² . The conveying speed of the precursor continuous sheet was set to 70 mm/min, and the angle formed by the blade of the slicing machine and the precursor continuous sheet was set to 5°.

This was fired in an air atmosphere using a roller hearth furnace. Firing is carried out by performing a degreasing step at an ambient temperature of up to 800° C. while continuously raising the temperature at 3° C./min while performing exhaust of 1.5 Nm ³ /h per 1 kg of the precursor continuous sheet conveyed through the furnace. , from over 800° C. to 1190° C., the temperature was raised at a rate of 20° C./min and held at 1190° C. for 30 minutes.
The tabs at both ends of the obtained continuous alumina fiber sheet with a width of 0.65 mm were removed by cutting to obtain a continuous alumina fiber sheet with a width of 600 mm.

The surface mass of the continuous alumina fiber sheet obtained, its variation, and the surface property were evaluated by the following methods.

For the surface mass, 36 specimens of 0.1 m × 0.1 m in size were cut out from the continuous alumina fiber sheet, 6 specimens in the width direction and 6 specimens in the conveying direction of the sheet, and their weights were measured. The surface mass value of each test piece was obtained by using the above method, and the arithmetic average value was taken as the average surface mass of the alumina fiber continuous sheet.
Further, the variation in the surface mass of the continuous alumina fiber sheet was the larger of the values calculated by the formulas (1) and (2).
100 x (maximum surface mass-average surface mass)/(average surface mass) Equation (1)
100 x (average surface mass-minimum surface mass)/(average surface mass) Equation (2)

Furthermore, the dispersion of the coefficient of friction of the obtained continuous alumina fiber sheet was evaluated by the following method.

A method for measuring the coefficient of friction of the continuous aluminous fiber sheet will be described with reference to FIG.
Ten samples of 7.6 cm×7.6 cm were extracted from the obtained continuous alumina fiber sheet along the width direction of the continuous alumina fiber sheet to prepare ten samples. Furthermore, the position from which the sample is extracted is shifted in the machine direction of the continuous alumina fiber sheet, and 10 samples of 7.6 cm × 7.6 cm are extracted from the continuous alumina fiber sheet along the width direction of the continuous alumina fiber sheet. 10 more samples were made. This operation was repeated to prepare a total of 100 samples. One side of each sample was parallel to the machine direction of the continuous alumina fiber sheet, and the other side was parallel to the width direction of the continuous alumina fiber sheet.

The obtained sample 42 was placed on a flat metal plate 41 (SUS304, surface treatment buff polishing #400). A weight 43 of 1155 g was placed on the sample 42 . The pressure per unit area applied to the sample 42 by the weight 43 was 20 g/cm ² . By moving the slide pedestal 44 in the direction of the arrow, the flat metal plate 41 was tilted so that the amount of displacement of the inclination angle φ of the flat metal plate 41 about the axis 45 was 1°/sec. Then, the angle (φ1) at which the sample started to move was measured. The coefficient of friction was calculated from the following formula.
Friction coefficient (μ) = tan (φ1)
Friction coefficients were measured for 100 samples, and the average value and standard deviation (σ) were calculated. Then, by dividing the standard deviation (σ) by the average value, the coefficient of variation (%) of the friction coefficient of the alumina fiber continuous sheet (= standard deviation (σ) / average value × 100) is calculated, and the value is The variation (CV) of the coefficient of friction of the alumina fiber continuous sheet was defined as the variation.

"Examples 2 and 3"
A continuous alumina fiber sheet was produced in the same manner as in Example 1, except that the type of slicing machine was changed. The slicing machine used is as follows.
Example 2: Band saw slicing machine (a slicing machine that rotates a band-shaped blade at high speed)
Example 3: Roll cutter slicing machine (a slicing machine that cuts by rotating a circular blade)

"Examples 4-6"
An aluminous fiber continuous sheet was produced in the same manner as in Example 1, except that the angle formed by the blade of the slicing machine and the precursor continuous sheet was changed.

"Examples 7 to 10, Comparative Example 1"
A continuous alumina fiber sheet was produced in the same manner as in Example 1, except that the amount of slicing was changed.

"Examples 11-13"
The surface mass of the alumina fiber continuous sheet was changed by adjusting the conveying conditions (conveying speed). A continuous alumina fiber sheet was produced under the same conditions as in Example 1 except for the above. These physical property values were measured and shown in Table 1.

From the results shown in Table 1, it can be seen that the continuous aluminous fiber sheet obtained by slicing the surface layer portion has a significantly reduced surface mass variation.
In addition, by adjusting the conveying conditions and the amount of slicing, it is possible to produce continuous aluminous fiber sheets having different surface mass values and small variations in surface mass.
Furthermore, it can be seen that the variation in the coefficient of friction of the continuous aluminous fiber sheet obtained by slicing the surface layer portion is small.
In addition, in the aluminous fiber continuous sheet obtained by slicing the surface layer portion, by setting the slice amount to 5% or more, even if the average value of the surface mass is 1350 g / cm ³ or more, the variation in the surface mass is reduced to less than 10%. I know you can.
Furthermore, by adjusting the conveying conditions and the amount of slicing, it is possible to produce an aluminous fiber continuous sheet having a surface mass value of 1350 g/ cm ³ or more and a small variation in coefficient of friction. By using this aluminous fiber continuous sheet, the variation in the coefficient of friction of the holding material can be reduced.

The continuous alumina fiber sheet of the present invention can be used for the same applications as conventional ones. For example, there are furnace materials for building furnace walls by block lining method, stack lining method, etc., and honeycomb for catalytic converters for purifying automobile exhaust gas, diesel putty, etc. It can be suitably used as a material for a holding material for fixing honeycombs such as honeycombs for curate filters.

1 slicing machine 10 blade 101 upper cutting blade (comb-shaped blade)
102 lower cutting blade (comb blade)
11 Blade drive motor 20 Precursor continuous sheet 21 Transporting net conveyor 30 Angle θ between the blade of the slicing machine and the precursor continuous sheet
41 metal plate 42 sample 43 weight 44 slide 45 shaft

Claims (6)

(I) A step of spinning a spinning dope containing an aluminum compound and a silicon compound as main components to obtain an aluminous fiber precursor; (III) slicing the surface layer of the continuous precursor sheet with a slicing machine to make it smooth; (IV) subjecting the continuous precursor sheet to entangling treatment by needling; and (V) the continuous precursor sheet. A method for producing an alumina fiber continuous sheet through a step of baking the sheet. 2. The slicing machine is a slicing machine having a mechanism in which two upper and lower cutting blades having comb-shaped blades are reciprocatingly slid to the left and right to cut by sliding contact between the comb-shaped blades. The method for producing the continuous alumina fiber sheet according to 1. The method for producing an aluminous fiber continuous sheet according to claim 1 or 2, wherein the ratio of the surface layer portion to be sliced and removed in the step (III) is 5 to 30% by mass with respect to the total weight of the precursor continuous sheet. The method for producing an alumina fiber continuous sheet according to any one of claims 1 to 3, wherein the average surface mass of the alumina fiber continuous sheet is 300 to 3000 g/m ² . The method for producing a continuous alumina fiber sheet according to any one of claims 1 to 4, wherein the surface mass variation of the continuous alumina fiber sheet is 10% or less. 6. The method for producing an alumina fiber continuous sheet according to claim 5, wherein the surface weight variation of the alumina fiber continuous sheet is 5% or less.

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