JPH04198337A - Carbonizable or graphitizable sheet, preparation thereof, and heat-insulating material - Google Patents

Abstract

PURPOSE:To provide the subject sheet excellent in flexibility and processability and giving a strong heat-insulating material excellent in surface-protecting property, wind pressure resistance and durability by compounding a rubbery component, a carbonaceous powdery material and a binder. CONSTITUTION:(A) A rubbery component, (B) a carbonaceous powdery material selected from a carbonizable or graphitizable powdery material and a carbonized or graphitized powdery material, and (C) a carbonizable or graphitizable binder are compounded preferably in amounts of 5-20wt.%, 50-90wt.%, and 10-40wt.%, respectively, and shaped into a sheet. Carbonizable or graphitizable fibers or carbon short fibers may be further compounded therein. The component C is preferably a phenolic resin, and the sheet shall be 0.2-3mm thick.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a carbonizable or graphitizable sheet suitably used as a heat-treating heat insulating material, a method for producing the same, and a heat insulating material.

[Prior art and problems to be solved by the invention] Insulating materials such as carbon fiber felt have excellent thermal stability at high temperatures. Used in formation furnaces, vacuum deposition furnaces, etc. In order to impart surface protection properties, high heat insulation properties, durability, etc. to this carbon fiber heat insulating material, (1) a heat insulating material whose surface is coated with a coating agent containing graphite powder and resin;
2) A heat insulating material in which a graphite sheet is attached to the surface, and a heat insulating material in which carbon fiber felt and graphite sheets are alternately laminated (Japanese Utility Model Publication No. 58-29129) are known.

However, when the above heat insulating material (1) is used on the furnace wall where wind pressure is large, the strength of the coating layer is low, so
The coating layer peels off. Therefore, the surface protection property of the heat insulating material is low, and the heat insulating property and durability are insufficient. Also (2
Although the insulation material of ) has a greater surface protection effect than the insulation material of (1) above, the strength of the graphite sheet itself is low;
Poor workability.

Therefore, an object of the present invention is to use carbonized or graphite sheets that are useful in obtaining a carbonaceous sheet that has excellent processability and can impart high surface protection properties, wind pressure resistance, durability, and large mechanical strength to heat insulating materials. The object of the present invention is to provide a sheet that can be used in various ways, and a method for manufacturing the same.

Other objects of the present invention are surface protection, wind pressure resistance, durability,
The purpose of the present invention is to provide a heat insulating material with excellent mechanical strength.

[Structure of the Invention] In order to achieve the above object, the present inventors, as a result of intensive studies, discovered that a rubbery component, a carbonaceous powder such as a carbonized or graphitized powder, and a material that can be carbonized or graphitized. The present invention was completed based on the discovery that a sheet containing a binder has excellent flexibility and processability, and that a strong carbonaceous sheet can be obtained by carbonizing or graphitizing the sheet. That is, the present invention provides a rubber component, at least one carbonaceous powder selected from carbonized or graphitized powder and carbonized or graphitized powder, and a carbonized or graphitized binder. Provided is a carbonizable or graphitizable sheet comprising:

The present invention also provides a rubbery component, at least one carbonaceous powder selected from carbonized or graphitized powder and carbonized or graphitized powder, and a carbonized or graphitized binder. Provided is a method for producing a carbonizable or graphitizable sheet, which involves kneading and forming a carbonizable or graphitizable sheet.

Furthermore, the present invention provides a heat insulating material in which the carbonized or graphitized carbonaceous sheet is bonded to a heat insulating material.

The definitions of terms used in this specification are as follows.

Carbonization refers to carbonizable components, for example, 450 to 15
It refers to firing treatment at a temperature of about 00°C. Graphitization refers to firing treatment at a temperature of, for example, about 1500 to 3000°C, and is included in the concept of graphitization even when the material does not have the crystal structure of graphite.

Carbon fiber refers to carbonized or graphitized fiber.

Flame-retardant treatment refers to the treatment of fibers other than pitch-based fibers, such as
This is a process of heating at a temperature of about 200 to 450°C in the presence of oxygen to form a heat-resistant layer on the surface to prevent melting during firing. The infusible treatment is, for example, a treatment in which pitch-based fibers are heated at a temperature of about 200 to 450° C. in the presence of oxygen to form a heat-resistant layer on the surface to prevent melting during firing.

The present invention will be explained in more detail below.

The rubber component contained in the carbonized or graphitized sheet is
It may be natural rubber, synthetic rubber, or recycled rubber. Examples of synthetic rubber include butadiene rubber, butyl rubber, chloroprene rubber, isoprene rubber, and styrene rubber.
Butadiene rubber, styrene-acrylonitrile rubber, styrene-butadiene-acrylonitrile rubber, acrylonitrile-butadiene rubber, acrylic rubber, silicone rubber, ethylene-propylene rubber (EPR), ethylene-propylene-diene rubber (EPDM), urethane rubber, fluororubber, chlorosulfonated Examples include polyethylene, shrimp chlorohydrin rubber, and polysulfide rubber. At least one of these rubbery components is used. The content of the rubbery component can be selected within a range that does not impair its function as a binder and provides flexibility to the sheet. The content of the rubber component is, for example, about 5 to 20% by weight.

Examples of the powder that can be carbonized or graphitized include bulk mesophase carbon obtained by infusibleizing crushed pitch, and low-temperature calcined coke obtained by carbonizing coal at a low temperature of about 500° C. and pulverizing it. Further, examples of the carbonized or graphitized powder include carbonaceous small spheres such as mesocarbon micropieces, coke please, scaly graphite, soil graphite, and artificial graphite. At least one of these carbonaceous powders is used. A particularly preferred powder is graphite.

Graphite powder, especially scaly graphite powder, has a strong tendency to be arranged in layers, so that not only the gaps between the graphite particles are extremely small or no gaps are formed, but also the graphite powder is excellent in terms of heat reflectance and non-transmission. Therefore, when graphite powder is used, radiant heat transfer can be suppressed, heat reflection efficiency and heat insulation efficiency can be significantly increased, gas permeability can be reduced, and wind pressure resistance can be further improved.

The particle size of the carbonaceous powder is usually about 0.1 to 500 μm.

The content of these carbonaceous powders is, for example, 50 to 90
It is about % by weight.

Examples of binders that can be carbonized or graphitized include thermosetting resins such as phenolic resins, furan resins, melamine resins, unsaturated polyesters, vinyl ester resins, diallyl phthalate resins, epoxy resins, polyimides, and thermosetting acrylic resins; Examples include thermoplastic resins such as polyacrylonitrile; coal or petroleum pitch. Among these binders, thermosetting resins such as phenolic resins are preferable because they have a high shape retention property when heated, a large residual carbon content when carbonized or graphitized, and can provide high bending strength. The residual carbon content of the binder is usually about 50 to 60% by weight or more. At least one of these binders can be used. The content of the binder is, for example, about 10 to 40% by weight.

The carbonizable or graphitizable sheet contains, in addition to the above components,
It is preferable to include carbonized or graphitized fibers or carbon fibers. Such fibers impart high mechanical properties such as bending strength and conductivity to a carbonaceous sheet obtained by carbonization or graphitization, and suppress the occurrence of warpage.

Examples of the carbonized or graphitized fibers include various fibers that can be used as carbon fiber materials, such as polyacrylonitrile fibers, phenol resin fibers, rayon, cellulose fibers, and pitch fibers. The carbonized or graphitized fibers may be flame-resistant or infusible. Among the fibers, carbon fibers are preferred. The fiber is a milled fiber, for example, a fiber length of 0.01 to 3I!
It is preferable to use it as a short fiber of about III. The content of the fibers is, for example, about 1 to 30% by weight.

The sheet may further contain thermoplastic resins other than those mentioned above. Examples of the thermoplastic resin include polyethylene, polypropylene, vinyl acetate polymer, polyvinyl alcohol, polyvinyl chloride, styrene polymer, acrylic polymer, polyester, polyurethane, and polyamide. The content of these thermoplastic resins is usually about 0 to 30% by weight. Note that these thermoplastic resins form voids in the carbonaceous sheet by carbonization or graphitization, thereby improving heat insulation properties.

The sheet contains additives such as a vulcanizing agent, a vulcanization accelerator, a vulcanization accelerating aid, an antiaging agent, an antioxidant, a filler, a softening agent and a plasticizer, a tackifier, and a coloring agent. Good too.

The thickness of the sheet can be selected as appropriate, for example, 0.
It is about 2-3III.

Such a sheet that can be carbonized or graphitized has excellent flexibility, does not cause cracks or the like even when bent along a curved surface, and can be smoothly adhered to a heat insulating material or the like. In addition, since the sheet has excellent flexibility, unlike conventional graphite sheets, it is not only easy to process, but also can usually be rolled, reducing storage volume.

The carbonizable or graphitizable sheet of the present invention can be produced, for example, through a cross-mixing process of mixing the rubber component, powder and granules, and a binder, and a molding process of forming the mixed substance into a sheet shape. .

In the mixing step, a conventional mixing machine such as a pressure kneader, a roll, etc. can be used.

At the time of crosstalk, for example, organic solvents such as alcohols, hydrocarbons, ketones, esters, and ethers may be used.

In the forming step, the mixed material is formed into a sheet using conventional equipment such as a calender such as a two-roll machine and an extruder.

Note that a vulcanization process may be performed after the molding process.

The heat insulating material of the present invention is comprised of the carbonized or graphitized carbonaceous sheet and a heat insulating material body to which the carbonaceous sheet is joined. The carbonaceous sheet and the heat insulating material body may be bonded via a carbonized or graphitized carbonaceous adhesive, such as a carbonized or graphitized thermosetting resin.

The type of the heat insulating material body is not particularly limited, and for example, a heat insulating material made of carbon fiber felt, a molded heat insulating material in which carbon fibers are integrated with the carbide or graphitized binder, etc. can be used.

These heat insulating material bodies may have a flat plate shape, a curved plate shape, a hollow cylindrical shape, or the like.

The bulk density and thickness of the heat insulating material body can be appropriately set depending on the desired heat insulating performance. The bulk density of the insulation material is usually 0.
,05~0.5g/-, preferably 0, 1~0
, about 3 g/ctA.

The carbonaceous sheet can be bonded to one or both sides of the heat insulating material body.

The heat insulating material of the present invention can be produced by, for example, bonding the sheet to the heat insulating material body using an adhesive that can be carbonized or graphitized as needed, and baking it in a vacuum or an inert gas atmosphere to carbonize or graphitize it. It can be manufactured by processing. In the bonding step, since the sheet has excellent flexibility, it can be bonded uniformly along the surface of the heat insulating material body, and has high workability and high working efficiency. Note that when a thermosetting resin is used as the adhesive and heated while being pressurized, the adhesive hardens due to the pressure and heat and becomes integrated with the heat insulating material main body. This pressure heating method can be selected depending on the shape of the heat insulating material body. For example, when the heat insulating material main body is flat, the adhesive may be pressed together with a carbonizable or graphitizable sheet and heated to harden the adhesive. In addition, when joining a sheet that can be carbonized or graphitized to the outer periphery of a three-dimensional heat insulating material body such as a hollow cylinder, the sheet that can be carbonized or graphitized is attached to the outer periphery of the heat insulating material body using an adhesive. The adhesive may be laminated, encapsulated in a heat-shrinkable film such as stretched polyethylene terephthalate, heated to shrink the heat-shrinkable film, and cure the adhesive.

Then, by firing, the sheet becomes carbonaceous, and a heat insulating material with a hard surface and a high mechanical strength in which the carbonaceous sheet and the heat insulating material main body are integrated can be obtained. Therefore, the carbonaceous sheet can improve the surface protection properties, wind pressure resistance, durability, and heat insulation properties of the heat insulating material main body. In addition, nitrogen, helium, argon, etc. are illustrated as an inert gas at the time of baking. The firing temperature can be arbitrarily set depending on the temperature of the heating furnace to which the heat insulating material is applied. The firing temperature is usually about 1500 to 2500°C.

[Effects of the Invention] The carbonized or graphitized sheet of the present invention has excellent flexibility and processability, and when fired, can be used as a heat insulating material, with high surface protection properties,
It is useful in imparting wind pressure resistance, durability, and high mechanical strength.

According to the manufacturing method of the present invention, a carbonizable or graphitizable sheet having the above-mentioned excellent properties can be obtained.

Further, the heat insulating material of the present invention has high surface protection properties, high wind pressure resistance, high durability, and exhibits high mechanical strength.

[Examples] The present invention will be explained in more detail based on Examples below.

Example 10 parts by weight of butyl rubber, 50 parts by weight of flaky graphite powder (manufactured by Nippon Graphite Co., Ltd., trade name CB-150, particle size 150 μm), phenol resin (manufactured by Kanebo Co., Ltd., trade name S-890)
) 25 parts by weight, carbon fiber milled fiber (donut (
Co., Ltd., trade name: Dona Carbo S-241) and 20 parts by weight of methyl ethyl ketone were mixed in a pressure kneader.
The mixture was kneaded for 0 minutes. The obtained compound was heated to 80° C., and a sheet molded product was produced using twin-axial rolls with a roll spacing of 1.2+n+n.

The sheet molded product has a thickness of 30III111 and a bulk density of 0.1.
The above phenolic resin solution was used to bond the surface of a flat heat insulating material made of 3 g/ec carbon fiber felt at 140° C. and a pressure of I Kg/c + 277) at 30° C.
Pressed for a minute. The obtained molded body was fired at 2700° C. in a nitrogen gas atmosphere to produce a heat insulating material in which the graphitized sheet and carbon fiber felt were integrated.

Comparative Example Instead of the sheet-shaped molded product, a graphite sheet (Sumitomo Metal Industries (Sumitomo Metal Industries)
A heat insulating material was produced in the same manner as in the example except that a heat insulating material manufactured by Co., Ltd., thickness 1.2'v) was used.

Bending strength (Kgf) of the heat insulating materials obtained in Examples and Comparative Examples
/cm) Compressive strength (Kgf /cm2)'
frill) was established. The bending strength was measured with the sheet surface on the tensile side, and the compressive strength was measured when a load was applied perpendicularly to the layer and when a load was applied parallel to the layer. The results are shown in the table below.

From the table, the heat insulating material of the example has greater mechanical strength and is reinforced than the heat insulating material of the comparative example.

Claims (5)

[Claims] 1. It is characterized by containing a rubbery component, at least one type of carbonaceous powder selected from carbonized or graphitizable powder and carbonized or graphitized powder, and a carbonized or graphitized binder. A sheet that can be carbonized or graphitized. 2. Rubber component 5-20% by weight, carbonaceous powder 50-9%
A carbonizable or graphitizable sheet according to claim 1, comprising 0% by weight of binder and 10-40% by weight of binder. 3. A carbonizable or graphitizable sheet according to claim 1, comprising carbonizable fibers, graphitizable fibers, or short fibers of carbon fibers. 4. A rubber component, at least one type of carbonaceous powder selected from carbonized or graphitizable powder and carbonized or graphitized powder, and a carbonized or graphitized binder are kneaded to form a sheet. A method for producing a carbonized or graphitized sheet that is formed into a shape. 5. A heat insulating material, wherein the sheet according to claim 1 is carbonized or graphitized and bonded to a main body of the heat insulating material.