JPH0659726B2 - High temperature insulating structural material and method for producing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel high temperature heat insulating structural material composed of a carbon fiber reinforced carbon plate and a foam and a method for producing the same.

"Prior Art" Conventionally, as a high temperature heat insulating structural material of this kind, a foam obtained by mixing a carbon micro hollow body with a foamable resin and foaming the carbon micro hollow body was attempted to improve the carbonization rate and the shrinkage rate. A method for producing carbon or graphite foam by firing is disclosed in, for example, Japanese Patent Publication No. 51-5836.

Although this carbon or graphite foam is recognized to have improved compressive strength, it does not have sufficient flexural strength and cannot be used as a structural material.

On the other hand, as a high temperature heat insulating material having excellent bending strength, a carbon micro hollow body, a glassy micro hollow body, and a carbon foam composed of a thermosetting resin or pitch,
A carbon foam insulation material obtained by laminating and integrating plate-like materials made of carbon or graphite is disclosed in, for example, JP-A-50-1417.
No. 46 is disclosed.

Although this carbon foam heat insulating material is excellent in strength and has the effect of imparting low air permeability and wear resistance, it has not yet obtained the robustness that can be used as a structural material.

Further, as a high temperature heat insulating material having low thermal conductivity and excellent robustness, a heat insulating material composed of heat insulating mineral fibers held in a matrix formed at least partially by pyrolytic carbon is disclosed in, for example, JP-A-56- It is disclosed in Japanese Patent No. 22694.

"Problems to be solved by the invention" The heat insulating material disclosed in JP-A-56-22694 is a mineral fiber impregnated with a thermosetting resin, and after curing the resin, a temperature of 600 ° C or higher. However, it is difficult to generate uniform voids during the thermal decomposition process due to the different shrinkage ratios of the mineral fibers and the matrix, and voids are formed at the interface between the mineral fibers and the matrix. There is a problem of concentration.

In other words, the voids concentrated at the interface between the mineral fiber and the matrix reduce the compressive strength and bending strength, and the carbonizable substances such as coal tar, tar pitch, and resin are reattached to these voids, and then fired again. However, the strength as a structural material could not be obtained unless the densification treatment for carbonization was sufficiently performed to fill the voids.

Furthermore, this densification treatment has the effect of increasing the thermal conductivity, and therefore adversely affects the performance as a heat insulating material. Therefore, it has strength as a structural material and maintains low thermal conductivity. Was very difficult.

The present invention aims to solve such conventional problems.

"Means for Solving Problems" In the present invention, carbon fibers having a fiber length of 3 mm or more are 30 to 80.
A carbon fiber-reinforced carbon plate obtained by impregnating the carbon fiber with a carbonizable resin so as to be in a weight%, curing and firing, and carbonizing the carbon fiber reinforced carbon plate, and a carbon microhollow body and a resin compact are fired. It is a high-temperature heat insulating structural material characterized by being laminated with the obtained carbon foam and integrated.

Further, the present invention provides a carbon fiber having a fiber length of 3 mm or more.
A carbon fiber reinforced carbon plate obtained by impregnating the carbon fiber with a carbonizable resin so as to be 30 to 80% by weight, curing, firing, and carbonizing, and a molded body composed of a carbon micro hollow body and a resin. It is a method for producing a high temperature heat insulating structural material, which comprises bonding the carbon foam obtained by firing with a graphite-based adhesive and firing.

The carbon fiber-reinforced carbon plate used in the present invention is a carbon fiber or graphite fiber having a length of 3 mm or more (hereinafter simply referred to as carbon fiber), for example, a carbon fiber cloth or a carbon fiber filament obtained by making paper. , A carbon plate or a graphite plate manufactured by impregnating a resin capable of carbonization or graphitization (hereinafter simply referred to as “carbonization”), stacking the obtained sheets if necessary, curing, and then firing and carbonizing the sheets. It is simply called a carbon plate). The length of the carbon fiber is 3
Those less than mm cannot fulfill a sufficient mechanical reinforcing function.

Further, there is no upper limit of the fiber length, and the carbon plate made of the continuous long fiber carbon fiber woven fabric is superior in tensile strength and bending strength to the carbon plate made of short fibers.

Furthermore, a carbon plate made of a three-dimensional product of continuous long-fiber carbon fibers is particularly excellent in shear strength between layers.

The arrangement of the carbon fibers is not limited and may be arbitrary.

That is, the orientation is not always required, and the fibers may be randomly present or orderly arranged, and may be fluffy or other commercially available shape.

As the carbonizable resin, a phenol-based resin or a furan-based resin having a relatively high residual carbon rate can be used, but other resins can be used as long as they can be carbonized such as tar pitch. Is.

The blending ratio of carbon fibers to the total amount of the carbon fiber reinforced carbon plate is 30 to 80% by weight.

If the compounding ratio of the carbon fiber is less than 30% by weight, the reinforcing effect cannot be obtained, and if it exceeds 80% by weight, the carbon plate obtained becomes brittle.

Further, in order to impart appropriate flexibility and adhesiveness to a sheet obtained by impregnating carbon fiber with a carbonizable resin and improve workability until curing, an appropriate amount of epoxy resin can be added.

Furthermore, in order to impart oxidation resistance to the carbon fiber reinforced carbon plate, when the carbon fiber reinforced carbon plate is located on the outer surface of the high temperature heat insulating structural material, silicon oxide, silicon carbide,
A process of coating alumina or boron or filling them may be performed.

Further, the firing temperature for carbonizing the sheet after curing is preferably 800 ° C. or higher.

If the firing temperature is less than 800 ° C, it is difficult to obtain a high-strength carbon fiber reinforced carbon plate due to insufficient carbonization treatment, and when used at a high temperature of 1000 ° C or higher, gas is generated and carbon fiber reinforced carbon is generated. The adhesive strength between the plate and carbon foam is reduced.

As the foam used in the present invention, carbon foam having excellent dimensional stability at a temperature of 1000 ° C. or higher is used.

The carbon foam is obtained by foaming and curing a carbonizable resin, firing and carbonizing the resin foam, or by mixing the carbonizable resin and the carbon microhollow body, foaming and curing. A carbonaceous material obtained by a method of baking and carbonizing a resin foam, a method of mixing a carbonizable resin and a minute hollow body made of a carbonizable resin, foaming and curing the resulting resin foam, and baking and carbonizing the resin foam. Graphite foam may be mentioned.

Among the above-mentioned carbon foams, those consisting of resin and carbon micro hollow bodies can easily and freely adjust the strength and thermal conductivity of the foam, and can easily disperse the voids of the foam uniformly and improve the performance. Since it is possible to produce a uniform product, the yield is good and it is preferable.

The firing temperature for carbonizing the resin foam is 80.
It is preferably 0 ° C or higher.

If the firing temperature is less than 800 ° C, it is difficult to obtain high-strength carbon foam due to insufficient carbonization treatment.
When it is used at a high temperature of ℃ or more, gas is generated and the adhesive strength between the carbon fiber reinforced plate and the carbon foam is reduced.

Next, the carbon fiber reinforced carbon plate and the foam are laminated and integrated to obtain a high temperature heat insulating structural material.

As a method of providing a laminated structure, for example, a method of firing a carbon plate and a foam separately, carbonizing and then adhering both by using a carbonizable resin, laminating and curing, firing, carbonizing, a carbon plate and a foam Separately curing and using a resin that can be carbonized at the stage of not carbonizing, bonding and laminating both, curing, firing, carbonizing, or carbonizing one of the carbon plate and foam and not the other carbon Here, there is a method of adhering and laminating both using a carbonizable resin, curing, firing, and carbonizing.

In the present invention, as shown in Examples 1 and 2, a method in which a carbon plate and a foam are separately fired and then both are adhered and fired using a carbonizable resin, more preferably a graphite-based adhesive, is used. preferable.

Further, the number of layers of the laminate is not limited, and any one such as one in which a carbon plate is in contact with one side or both sides of the foam or one in which the foam and the carbon plate are alternately laminated in a plurality of layers is adopted. Good.

[Examples] Examples of the present invention will be described below.

Example 1 60 parts by weight of long-fiber carbon fiber (manufactured by Toho Bethlon Co., Ltd., Vesphite, HTA-6000) was added to a resol-type phenol resin (constituted by Gunei Chemical Industry Co., Ltd.) having a concentration of 30% by weight with acetone. PL-2211) 40 parts by weight (nonvolatile component)
Impregnate and arrange in one direction to form a sheet, and after drying this sheet for 10 minutes at 80 ° C to remove volatile components, align the fiber directions and stack 10 sheets.

This stack was cured by autoclaving at 150 ° C for 3 hours in a vacuum pack at a pressure of 7 kg / cm ² and cured, and then post-cured in an oven at 200 ° C and then heated to 1000 ° C in an inert atmosphere until 3 ° C Firing was performed while raising the temperature at a temperature rising rate of ° C / hour to obtain a carbon fiber reinforced carbon plate having a thickness of about 2 mm.

On the other hand, a carbon micro-hollow body (average particle size 200 μm, bulk specific gravity)
0.12 g / cm ³ ) and a novolac hexa type phenol resin (Sumitomo Durres Co., Ltd., PR-50099) were mixed at a weight ratio of 36:64 and mixed until uniform using a kneader. Pour into a 150mm x 150mm x 50mm mold, press mold at 150 ° C for 30 minutes to cure, and then post-cure in an oven at 200 ° C, then to 1000 ° C in an inert atmosphere at 10 ° C / hour. Carbon foam was obtained by firing while raising the temperature at the heating rate.

Next, the carbon fiber reinforced carbon plates were attached to both surfaces of this carbon foam using a commercially available graphite-based adhesive, and fired at 1000 ° C. in an inert atmosphere.

The characteristic values of the obtained high temperature heat insulating structural material are as shown in Table 1.

Example 2 Ten short carbon fibers (trade name: Toray Industries, Inc., trading card, T-300) were used.
40 parts by weight of resol type phenolic resin (PL-2211 manufactured by Gunei Chemical Industry Co., Ltd.) with a concentration of 30% by weight of acetone on 60 parts by weight of carbon felt in which chops cut into mm lengths are arranged irregularly Part (nonvolatile component) is impregnated to form a sheet and treated in the same manner as in Example 1 to a thickness of about 2 mm.
A carbon fiber reinforced carbon plate of was obtained.

Next, the carbon fiber reinforced carbon plates were attached to both sides of the same carbon foam as in Example 1 by using a commercially available graphite-based adhesive and fired at 1000 ° C. in an inert atmosphere.

The characteristic values of the obtained high temperature heat insulating structural material are as shown in Table 1.

Comparative Example 1 The results of measuring the characteristic values of the simple carbon foams used in Examples 1 and 2 are shown in Table 1.

[Advantages of the Invention] As described above, according to the present invention, since the carbon fiber reinforced carbon plate and the foam are laminated and integrated, low thermal conductivity as a heat insulating material and robustness as a structural material are combined. A high temperature insulating structural material having the same can be obtained.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshio Kaneshiro 1 Kawasaki-cho, Chiba-shi, Chiba Kawasaki Steel Co., Ltd. Technical Research Headquarters (72) Inventor Kazuhiro Hasegawa 1 Kawasaki-cho, Chiba-shi Kawasaki Steel Co., Ltd. Inside the Research Headquarters (72) Inventor Nobuo Tsuchiya 1 Kawasaki-cho, Chiba-shi, Chiba Inside Kawasaki Steel Co., Ltd. Technical Research Headquarters (72) Inventor Michio Nakai 1 Kawasaki-cho, Kakamigahara-shi, Gifu Kawasaki Heavy Industries Ltd. ) Inventor Koji Ito 1 Kawasaki-cho, Kakamigahara-shi, Gifu Kawasaki Heavy Industries Ltd. Gifu factory (72) Inventor Masanori Kiyoshige 1-1 Kawasaki-cho Akashi-shi Hyogo Kawasaki Heavy Industries Ltd. Akashi factory (56) References JP-A-50-141746 (JP, A) JP-A-57-100985 (JP, A) JP-B-50-29838 (JP, B2)

Claims (2)

[Claims] 1. A carbon fiber having a fiber length of 3 mm or more is 30 to 30.
The carbon fiber was impregnated with a carbonizable resin so as to be 80% by weight, hardened, baked, and carbonized to obtain a carbon fiber-reinforced carbon plate, and a carbon microhollow body and a molded product made of resin were baked. A high temperature heat insulating structural material characterized by being laminated and integrated with the carbon foam obtained as described above. 2. Carbon fiber having a fiber length of 3 mm or more is 30 to 30.
The carbon fiber was impregnated with a carbonizable resin so as to be 80% by weight, hardened, baked, and carbonized to obtain a carbon fiber-reinforced carbon plate, and a carbon microhollow body and a molded product made of resin were baked. A method for producing a high temperature heat insulating structural material, which comprises bonding the obtained carbon foam with a graphite-based adhesive and firing.