JP3390182B2 - Carbon fiber based heat insulating material and method for producing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carbon fiber-based molded heat insulating material having excellent heat insulating properties, particularly high temperature insulating properties. More specifically, the present invention is a carbon that is extremely stable in an inert atmosphere, exhibits excellent heat resistance and morphological stability in the range of 500 to 2,800 ° C., and particularly has excellent heat insulating properties against radiative heat transfer. A fiber type heat insulating material is provided. Furthermore, the carbon fiber-based molded heat insulating material of the present invention has excellent heat insulating properties in a high temperature range, and is capable of melting glass, firing ceramics, refining metal,
It can be used for heat insulation of high-temperature furnaces for sintering ceramics or firing carbon materials. Furthermore, the carbon fiber-based molded heat insulating material of the present invention is excellent in radiation stability and exhibits excellent performance as a heat insulating material for nuclear reactors and nuclear power generation facilities.

[0002]

2. Description of the Related Art Conventionally, porous ceramics have been widely used as a heat insulating material used in a high temperature range. While these insulations do have excellent high temperature stability,
In order to provide low thermal conductivity, it is necessary to have a significant amount of vacancies . These holes are not completely closed bubbles, but the gas flow is usually quite limited. This is because if there is a large defect that allows gas to easily flow around the holes, the strength of the ceramic molded product will decrease, and in order to prevent this, it is connected to the outside with a fairly small passage. is there. Due to such morphological characteristics, conventional ceramics heat insulating materials are generally weak to rapid heating and rapid cooling, and have a problem called spalling, which frequently causes structural collapse from the surface due to temperature changes. In order to obtain a heat insulating material with less spalling, it is generally necessary to select a material having a low porosity and poor heat insulating properties, and there is a problem that a large amount of heat insulating material is required.

The conventional ceramic heat insulating material has an excellent heat insulating effect against convective heat transfer and conductive heat transfer, but it does not emit light rays such as infrared rays or visible light, which are the main components of radiant heat transfer. There is a problem that the ability to absorb is generally small and the adiabatic effect on radiant heat transfer is generally insufficient. As a carbon-based heat insulating material that has a large ability to absorb light rays, it is known to use expanded graphite, but it is necessary to use natural graphite having a large crystal size as a raw material, which is high in cost and contains many impurities. There's a problem. In order to solve these problems, it has been widely practiced to use ceramic fibrous materials as a heat insulating material. Although such a fibrous material certainly exhibits an excellent heat insulating effect, it is difficult to manufacture, and thus it is generally expensive, which is one of the reasons why the high temperature furnace is expensive.

Considering the performance of the heat insulating material from the viewpoint of the heat insulating mechanism, in the high temperature region of 500 ° C. or higher, the main body of the heat transfer mechanism shifts to radiative heat transfer, and the contributions of convective heat transfer and conductive heat transfer are relatively large. Since it is extremely small, there is a problem that a heat insulating material effective in a low temperature range of 200 ° C. or lower does not always show good performance in a high temperature range . In particular, in the case of a ceramics-based fibrous heat insulating material, although it has an excellent heat insulating effect in a low temperature range, it generally absorbs and scatters light rays because the transparency of the fiber is generally good and the surface of the fiber is extremely smooth. It has a small capacity and there is a problem that the adiabatic effect of radiative heat transfer is not sufficient in the high temperature range.

[0005]

DISCLOSURE OF THE INVENTION The present invention has the problems that the conventional heat insulating material in a high temperature range is weak against abrupt temperature change, the heat insulating effect on radiant heat transfer is generally insufficient, and the ceramic type heat insulating material. Fibrous insulation is generally expensive,
It is intended to solve the problem that the heat insulation effect for radiant heat transfer is insufficient.

[0006]

As a result of various studies on the above problems, the inventors of the present invention have found that the pitch system having low hygroscopicity (2% or less).
Using carbon fiber material, a high bulk density (0.01 to 0.5 g
/ Cm ³ ) and processed with a sheet of lightly carbonized sheets
The layers, impregnated and cured with a binding material matrix that can be non-fibrous carbides spot gluing between the carbon fibers by carbonization,
Further, by using a molded heat insulating material which is further carbonized and held in a molded shape, the thermal conductivity in the thickness direction of the molded heat insulating material is extremely small ( 1.0 kcal / m · hr ° C).
Below), low hygroscopicity and excellent in absorption of radiant heat transfer
Because there, are very useful as thermal insulation of the hot zone, during operation
Useful for preventing deterioration of shortening insulation between, pairs 且 one radiation
Found that a heat insulating material with excellent stability can be provided,
The present invention has been completed.

That is, the present invention has: a bulk density of 0.0
1-0.5g / cm³Molded insulation at 2,200 ℃
Thermal conductivity in the thickness direction of the material is 1.0 kcal / m · hr ° C
A carbon fiber-based molded heat insulating material, comprising:
System molded insulationIn an atmosphere with a temperature of 20 ° C and relative humidity of 65%
Manufactured using pitch-based carbon fibers with a hygroscopicity of 2% or less
Done, The carbon fiber content is about 60 to 95% by weight,
And the molded shape is maintained by the inclusion of non-fibrous carbide.
It is a carbon fiber type heat insulation material that is non-fibrous.
Carbides of phenol resin, furan resin, amino resin
1 or 2 selected from the group of fat, tar and pitch
It is also characterized by the fact that it is derived from more than one kind of substance.
In that the fibers have an average single fiber diameter of 1 to 9 μm
Also has features,   (A) Precursor fiber
In the process directly connected to the spinning process of spinning by the melt blow method
Collect it in the shape of a catSheet(B) then infusible
(C) made of carbon fiber
2 to 100 punch / c
m²Needle punching with the density of (d)
Enol resin, furan resin, amino resin, tar and pin resin
Containing one or more substances selected from the group of
After soaking, cure the resin and carbonize the impregnated material.
LetDescribed in any ofCarbon fiber type heat insulation material
A method of manufacturing the same is also provided.

The details will be described below. The carbon fiber used in the carbon fiber-based molded heat insulating material of the present invention preferably has an average single fiber diameter of 1 to 9 μm. In addition, the average single fiber diameter of the carbon fiber that has been lightly carbonized before being subjected to forming processing such as needle punching is slightly (about 10%) larger than the average single fiber diameter of the carbon fiber fired at high temperature. The average single fiber diameter is represented by an average value of respective values obtained by measuring, for example, 100 randomly selected single fiber samples with an optical microscope or an electron microscope.

The heat insulating material in the high temperature range has a thermal conductivity of 1.0 kca in the thickness direction of the molded heat insulating material at 2,200 ° C.
l / m · hr ° C. or less , preferably 0.7 kcal / m ·
It is not higher than hr ° C. At this time, the average single fiber diameter is 9 μm
If it exceeds, the thermal conductivity is 1.0kcal / m · hr
It is difficult to keep the temperature below ℃. On the other hand, if it is less than 1 μm, various troubles are likely to occur at the stage of fiberizing the precursor, irregular shaped particles that do not show a fibrous state are often mixed, and yarn breakage frequently occurs, which is not preferable. As described above, by using the carbon fibers having a small diameter as the constituent fibers of the heat insulating material, the heat insulating effect on the radiant heat transfer becomes extremely high.

[0010] As the carbon fiber, in terms of spinning or the like into a high heat insulating effect shape, petroleum pitch-based, it is necessary to use a pitch-based coal-pitch based, etc., preferably those of mesophase pitch-based is there. Among pitch-based carbon fibers, those made from mesophase pitch as a raw material have smaller hygroscopicity, and therefore have properties suitable as the carbon fiber-based molded heat insulating material of the present invention.

As the carbon fiber, it is necessary to use one having a low hygroscopicity. That is , it is necessary that the hygroscopicity is 2% or less in an atmosphere at a temperature of 20 ° C and a relative humidity of 65%.
An essential, good Mashiku is 0.1% or less. Hygroscopicity value
Is the weight of the absorbed moisture weight of the carbon fiber molding insulation
It is the ratio to . When it is used as a heat insulating material, if it has a high hygroscopicity, there is a problem that water vaporization occurs when the temperature rises from room temperature, reducing the heat insulating effect, and that water vapor is brought into the atmosphere around the carbon fibers, There is a problem that causes deterioration of carbon fibers at high temperatures.

In the present invention, the non-fibrous carbides which are interposed between the carbon fibers and used to hold the carbon fibers in the molded shape are phenol resin, furan resin,
It is derived from one or more substances selected from the group consisting of amino resin, tar and pitch. In the present invention, since the above-mentioned specific resin or tar is used as the binder, not only the mat-like material of carbon fibers is simply laminated, but also the fibers are bonded with resin or tar in the intermediate stage. It can be molded and can provide molded insulation of fairly complex shape.

The carbon fiber type molded heat insulating material of the present invention has a temperature of 2
Hygroscopicity is 2% or less in an atmosphere of 0 ° C and 65% relative humidity
It is manufactured using pitch-based carbon fiber and has a bulk density of 0.0
1 to 0.5 g / cm ³ , preferably 0.05 to 0.5 g
/ Cm ³ ; thermal conductivity in the thickness direction of the molded heat insulating material at 2,200 ° C. is 1.0 kcal / m · hr ° C. or less, preferably 0.7 kcal / m · hr ° C. or less; carbon fiber content is about It is 60 to 95% by weight, and is characterized in that the molded shape is maintained by the inclusion of non-fibrous carbide.

That is, the bulk density of the molded heat insulating material of the present invention is
It is necessary to be 0.01 to 0.5 g / cm ³ ,
It is preferably 0.05 to 0.5 g / cm ³ . In order to improve the heat insulating effect, it is preferable to make the gas layer in the heat insulating material as fine as possible. Further, unless the orientation of the carbon fibers in the heat insulating material is continuous in the Z-axis direction, the larger the bulk density is, the more the heat insulating effect is improved. A bulk density of 01 to 0.5 g / cm ³ is applicable. Bulk density is 0.01g / cm ³
If it is too small, the thermal conductivity will be high, probably because the light scattering effect will be low. Conversely, if the bulk density exceeds 0.5 g / cm ³ and is too high, the thermal conductivity will be high, resulting in heat insulation. The effect decreases. The bulk density of the molded heat insulating material can be adjusted to a predetermined bulk density by adjusting the density of the needle punch or the pressure applied during carbonization.

In the carbon fiber-based molded heat insulating material of the present invention, the content of the constituent carbon fibers must be about 60 to 95% by weight.
And preferably about 70-80% by weight. vice versa,
The content of the binder matrix, which becomes a non-fibrous carbide by carbonization, is about 5-40% by weight, preferably about 10-30.
It is desirable that the content be wt%. Furthermore, from the viewpoint of the heat insulating property of the molded heat insulating material, it is not preferable that the carbon fiber and the matrix are continuous in the thickness direction (Z direction to be heat insulated), and it is preferable that the carbon fiber and the matrix are oriented only in the X and Y planes. Conceivable.

[0016] Generally, the binder matrix is used for holding the molded shape so as to withstand processing and the like, and it is generally preferable to bond the fibers by point bonding, and it is preferable that the matrix itself is as small as possible. However, in order to maintain the molded shape, it is necessary to secure a certain amount of matrix, and the content of the matrix is usually about 10-40.
% By weight. The content rate of the carbon fiber or the content rate of the matrix binder in the present invention is a calculated value based on the graphitization yield of the fiber alone by the heat treatment.

The method for measuring the thermal conductivity of the carbon fiber type molded heat insulating material defined in the present invention is JIS A 1
412 “Method of measuring thermal conductivity of heat insulating material”. However,
A radiation thermometer is used because it is difficult to use a thermocouple as in the standard to measure temperature. The carbon fiber-based molded heat insulating material of the present invention has a thermal conductivity in the thickness direction of the molded heat insulating material at 2,200 ° C. of 1.0 kcal / m · hr ° C. or less, preferably 0.7 k cal / m · hr ° C. It is the following.

That is, the carbon fiber-based molded heat insulating material of the present invention is
As described above, (a) the bulk density of the molded heat insulating material is 0.01 to
0.5 g / cm ³ , preferably 0.05 to 0.5 g / c
(b) Heat transfer in the thickness direction of the molded heat insulating material at 2,200 ° C in a molded state with a high bulk density of m ^3.
The conductivity is 1.0 kcal / m · hr ° C or less, preferably
It is less than 0.7 kcal / m · hr ° C and has a hygroscopic property of 2 in an atmosphere of (C) temperature of 20 ° C and relative humidity of 65%.
% Pitch carbon fiber is used (d) The carbon fiber content in the heat insulating material is about 60 to 95% by weight.
(That is, the content of the binder matrix is about 5 to 40% by weight so that the carbon fibers can be maintained in a molded state by point bonding.) (E) The molded shape is maintained by interposing non-fibrous carbide [( f) in addition, due Ru] used as a small diameter which was constructed of carbon fiber insulation materials referred to the average single fiber diameter 1 to 9 m, it can exhibit an extremely high heat insulating effect represented by (a) the thermal conductivity value In addition, it exhibits excellent heat insulation properties especially for radiative heat transfer, and (b) is stable up to about 2,800 ° C in an inert atmosphere.
It has a technical significance in that it can be used as a heat insulating material at high temperatures .

The carbon fiber-based molded heat insulating material according to the present invention is manufactured by : (a) a sheet- shaped product obtained by collecting in a sheet form in a step directly connected to a spinning step of spinning a precursor fiber by a melt blow method. And (b) then infusibilized and lightly carbonized, (c)
A required number of sheets of the obtained carbon fiber were laminated and needle punched at a density of ^{2 to} 100 punches / cm ² , and (d) a group of phenol resin, furan resin, amino resin, tar and pitch. After impregnating one or more substances selected from the above, the resin is cured,
(e) It is carried out by carbonizing the impregnated substance.

The manufacturing method will be described in more detail below. (a) Step; (a) In the spinning step used for producing the precursor fiber, any spinning means such as a centrifugal spinning method, a spunbond method, and a meltblowing method can be adopted.
A monofilament having a small thickness is preferable because it can be produced relatively easily. Since the radius of curvature of the thin object as the surface of single fiber is low, there is a tendency high ability to scatter light at its surface, it is thought greatly contribute to heat insulation against radiant heat transfer. Further, it is known that thinner single fibers contribute to heat insulation against convective heat transfer. From these facts, it is considered that the fibers obtained by the melt blow method have excellent heat insulating properties in a high temperature range. Among the precursor fibers used in the present invention, the pitch fibers produced by the melt blow method are particularly excellent as the constituent fibers of the molded heat insulating material. The reason is that the fibers are generally not straight and have curls and crimps. The part where the fiber is not linear gives the fiber the allowance to move during needle punching, and the rate at which the fiber is cut is small.
In the place where the fibers are entangled with each other, the ratio of being inclined to the surface of the sheet-like material is high, the conductive heat transfer through the fibers is small, and the heat insulating effect is not blocked.

(B) By using pitch-based carbon fiber , especially mesophase pitch- based carbon fiber, a carbon fiber molded heat insulating material having low hygroscopicity is provided. Specifically, when spinning is performed by the melt blow method, the spinneret temperature is usually 290.
C. to 360.degree. C., gas temperature 310 to 380.degree. C., and gas ejection speed of 100 to 340 m / sec. The spinning conditions may be spinning through a slit or a spinning hole provided in a nozzle.

(C) Further, in the production method of the present invention, it is necessary to collect in a sheet form into a sheet form in a step directly connected to the spinning step. According to such a method, as compared with the conventional non-woven fabric manufacturing process, since it does not include a step of damaging a fiber having a small elongation such as opening and carding, the product does not include a fine fiber. There is. The finely-divided fibers have a problem that they move during use of the heat insulating material to contaminate the surroundings or clog the filter of the ventilation system. Furthermore, in the method of collecting in a sheet shape in the step directly connected to the spinning step,
It has the advantage that the sheet can be manufactured generally at low cost. (D) In the method of the present invention, following the step of collecting in a sheet form in the step (a), if necessary, the obtained precursor fiber sheet material is continuously cross-lapped to give a unit weight unevenness. It is also possible to use a laminated sheet-like product without the above.

Step (b): In the method of the present invention, infusibilization and mild carbonization treatment can be arbitrarily applied according to a conventional method. For example, the infusibilizing treatment is carried out under the temperature conditions of a temperature rising temperature of 0.2 to 13 ° C./minute, preferably 2 to 10 ° C./minute and 200 to 400 ° C., air, oxygen or NO.
The heat treatment is performed in an atmosphere of an oxidizing gas such as x. Further, carbonization treatment, then, needle-punched on relation of performing shaping process such as, for mild carbonization
Need to For example, according to a conventional method, 300 to 1 at a temperature rise temperature of 5 to 100 ° C./min in an inert gas such as nitrogen gas.
Carbonize at 500 ° C, preferably 500-1000 ° C.

(C) Step: Next, a required number of the obtained infusibilized and carbonized fiber sheet materials are laminated according to the purpose and use, and needle punching is performed. In this case, it is necessary to perform needle punching with a density of ^{2 to} 100 punches / cm ² . When the needle punch density is less than 2 punches / cm ² , the strength of the obtained carbon fiber-based molded heat insulating material is weakened, which causes a problem in handleability and is not preferable. Further, if the needle punch density exceeds 100 punches / cm ^2, since the content of the carbon fibers oriented in the direction perpendicular to the plane of the insulating material increases, the thermal conductivity is high on the conduction heat transfer, reduced insulation effect Is not preferable, and further, the strength of the molded heat insulating material is reduced by cutting the fiber, which is not preferable.

(D) Step; (a) First, a needle-punched sheet- like material is treated with one or more substances selected from the group consisting of phenol resin, furan resin, amino resin, tar and pitch. It is impregnated with a binder matrix that is present and can be converted into a non-fibrous carbide by carbonization, and the point-bonding is performed to such an extent that carbon fibers can be maintained in a molded state. In this case, the impregnation amount of the binder matrix should be the minimum amount that can retain the shape of the molded insulation.
Bur, preferably an amount which content corresponds to about 5 to 40% by weight of the matrix in the shaped insulation. (B) Then, the impregnated binder matrix is subjected to a conventional method,
For example, it is cured by means such as heating. (C) Finally, the treated product is carbonized according to a conventional method. For example, 900 to 20 in the presence of an inert gas such as nitrogen gas.
It is carried out by heat treatment at 00 ° C. for a certain period of time.

The carbon fiber-based molded heat insulating material of the present invention is not simply a laminate of the carbon fiber sheet-like materials as described above, but the carbon fibers are separated by a resin or tars in the intermediate step (d). Since it can be bonded and molded, it can be made into a considerably complicated shape.

[0027]

[Function] Since heat transfer in the high temperature range is mainly radiant heat transfer,
It is quite different from the heat transfer in the low temperature range where the convective heat transfer and the conductive heat transfer are the main components. INDUSTRIAL APPLICABILITY The carbon fiber-based molded heat insulating material of the present invention is excellent in the ability to absorb and scatter rays of light involved in radiant heat transfer, and has a good heat insulating effect on radiant heat transfer. The reason why the carbon fiber-based molded heat insulating material of the present invention has a large heat insulating effect on radiative heat transfer is that a material having a higher bulk density ( and finer single fibers) has a smaller radius of curvature on the surface, and thus has a larger ability to scatter light. , It is considered that it greatly contributes to heat insulation against radiative heat transfer. Further, among the raw materials of the carbon fiber-based molded heat insulating material of the present invention, the reason why the precursor pitch- based carbon fiber produced by the melt-blowing method is particularly excellent is that the carbon fiber is not generally linear and curls or crimps are used. Is contained in a large amount. The part where the pitch-based carbon fiber is not linear gives a space for the fiber to move during needle punching, the rate of fiber cutting is reduced, and the surface of the sheet- like material is entangled at the place where the carbon fiber is entangled. It has an advantage that the heat insulation effect is not impaired despite the fact that the ratio of the slanting is high, the conductive heat transfer through the carbon fiber is small, and the entanglement is advanced.

[0028]

The present invention will be described in detail with reference to the following examples, which do not limit the scope of the present invention.

Example 1 Softening point 284 ° C., mesophase content 10
Fibers are manufactured by a melt-blowing method using 0% petroleum pitch as a raw material, and 30 g / m ² on a net conveyor.
A pitch fiber sheet having a weight per unit area was collected. The continuously obtained sheets are laminated with a horizontal cross wrapper, and 6
A laminated sheet having a basis weight of 00 g / m ² and having a uniform basis weight was obtained. This laminated sheet of pitch fibers was heat treated while being heated to 300 ° C. in air at a temperature rising rate of 5 ° C./min to be infusibilized, and then 615 at a temperature rising rate of 5 ° C./min in an inert gas. The temperature was raised to ℃ and carbonized slightly. Continuing,
Punch density is 13 times / cm ² and bulk density is 0.11 g / c
After producing a mat-like material of m ³ , two sheets of this sheet- like material were overlaid, and a resole-type phenol resin (“Priofen” manufactured by Dainippon Ink and Chemicals, Inc.) was used so that the fiber content was 90% by weight. It was dipped in the sheet material and heat-cured at 165 ° C. The maximum temperature of this sheet- shaped molding is 2000 ° C.
Was carbonized to obtain a molded heat insulating material having a bulk density of 0.15 g / cm ³ . The average diameter of single fibers in the obtained molded heat insulating material was 6.5 μm. 2200 ℃ of the obtained molded insulation
The thermal conductivity at 0.26 kcal / m · hr was measured by measuring the thermal conductivity with the high temperature thermal conductivity measuring device (ITC 25-VRII) manufactured by Ishikawajima Harima Heavy Industries Co., Ltd.
It was ℃.

[0029]

Example 2 Sheets having various bulk densities obtained by spinning the melt-blown method in the same manner as in Example 1 and changing the pressure applied to the infusible sheet-like material during the light carbonization to 1 to 20 kg / cm ^2. A substance was obtained. This sheet material was needle punched with a punch density of 7 times / cm ^{2 in} the same manner as in Example 1 and impregnated with the same resol type phenol resin as used in Example 1 so that the fiber content was 90% by weight. Then 16
Cured by heating at 5 ° C., to carbonize the whole was heated further to 2000 ° C., for various molded heat insulating material obtained in Example 1
When the bulk density and the thermal conductivity were measured in the same manner as above, the results were as follows. The average diameter of single fibers of the carbonized carbon was 6.5 μm.

[0030]

[Table 1] * 1; g / cm ³ , * 2; kcal / m · hr ° C Note that test numbers No. 1 to 4 are examples and No. 5 is a comparative example.

[0031]

Example 3 Softening point 238 ° C. Coal-based isotropic pitch was used as a raw material, spinning was carried out by the melt blow method using the same apparatus as in Example 1, and collected in a sheet form in the same manner as in Example 1, Melting, mild carbonization, lamination and needle punching to obtain a geat- like material were impregnated with a resole-type phenol resin so as to have a fiber content of 90% by weight and cured in the same manner as in Example 1. Carbonized . Obtained success
The thermal conductivity of the shaped insulation was measured and found to be 0.
It was 60 kcal / m · hr ° C. The average diameter of the single fibers after carbonization was 7 μm.

[0032]

[Example 4] Using the same apparatus as in Example 1, spinning was carried out by the melt-blowing method, and at that time, the discharge amount of the pitch per spinning hole was changed to prepare fibers having different average diameters of monofilaments. In the same manner as in Example 1, the material was sampled into a sheet, infusibilized and lightly carbonized, two sheets were laminated, and needle punching (punch density 7 times / cm ² ) was performed to form a sheet . The obtained laminated sheet was impregnated with a resole-type phenol resin in the same manner as in Example 1 to be cured and carbonized, and the bulk density was 0.
A molded insulation of 1 g / cm ³ was made. A variety of formation obtained
With respect to the shaped heat insulating material , the single fiber average diameter and the thermal conductivity were measured in the same manner as in Example 1, and the results were as follows.

[0033]

[Table 2] * 1; μm, * 2; kcal / m · hr ° C Test numbers No. 1 to 3 are examples, and Nos. 4 and 5 are comparative examples.

[0034]

The carbon fiber-based molded heat insulating material of the present invention is inactive.
It is extremely stable in a volatile atmosphere , exhibits excellent heat resistance and morphological stability in the range of 500 to 2800 ° C., and provides an excellent heat insulating material against radiative heat transfer. Further, the carbon fiber-based molded heat insulating material of the present invention has excellent heat insulating properties in a high temperature range, and is suitable for high temperature furnaces for melting glass, firing ceramics, refining metals, sintering ceramics or firing carbon materials. It can be used for heat insulation. Further, the carbon fiber-based molded heat insulating material of the present invention is excellent in stability against radiation, and exhibits excellent performance as a heat insulating material for nuclear reactors and nuclear power generation facilities. In particular,
Hygroscopicity of mesophase pitch carbon fiber molded insulation is low
Therefore, there are problems caused by water vaporization and high temperature steam at the time of temperature rise.
It is possible to avoid problems, shorten the operating time and prevent deterioration of the heat insulating material.
It is for .

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-60480 (JP, A) JP-A-1-153572 (JP, A) JP-A-2-269806 (JP, A) Actual Kaihei 2- 106487 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) C04B 35/83

Claims (4)

(57) [Claims] 1. A bulk density of 0.01 to 0.5 g / cm ³ ,
A carbon fiber-based molded heat insulating material having a thermal conductivity in the thickness direction at 2,200 ° C. of 1.0 kcal / m · hr ° C. or less, wherein the carbon fiber-based molded heat insulating material has a temperature of 20.
Hygroscopicity is 2% or less in an atmosphere of ℃ 65% relative humidity
A carbon fiber-based molded heat insulation manufactured by using pitch-based carbon fiber, characterized in that the carbon fiber content is about 60 to 95% by weight, and that the molded shape is maintained by the inclusion of non-fibrous carbide. Material. 2. The non-fibrous carbide is a phenol resin,
The carbon fiber-based molded heat insulating material according to claim 1, which is derived from one or more substances selected from the group consisting of furan resin, amino resin, tar and pitch. 3. The carbon fiber-based heat insulating material according to claim 1, wherein the carbon fibers have an average single fiber diameter of 1 to 9 μm. 4. (a) A precursor is collected into a sheet in the form of a sheet in a step directly connected to a spinning step in which a precursor fiber is spun by a melt-blowing method, and (b) is then infusibilized and lightly carbonized, and (c) ) A required number of sheet- like materials made of the obtained carbon fibers are laminated and needle punching with a density of ^{2 to} 100 punches / cm ² is performed, and (d) further phenol resin,
After impregnating furan resin, amino resin, one or more substances selected from the group consisting of tar and pitch, performs the curing of the resin, characterized in that to carbonize the material soaked-entrapped claim 1 4. The method for producing a carbon fiber-based molded heat insulating material according to any one of 3 to 3 .