Multilayer insulating material and process for production thereof
AssigneeKureha Kagaku Kogyo Kabushiki Kaisha
InventorsFumio Kodama, Noboru Ohyama
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Abstract
By bonding a graphite sheet possessing tightness to at least one surface of carbon fiber felt sheet possessing gas permeability by means of a carbonaceous binder, a multilayer thermally insulating material suitable for use in a heating furnace employing a nonoxidizing atmosphere is obtained. This insulating material has mechanical strength which does not decrease with a long period of use and gives rise to little contamination of articles being heated in the furnace.
Claims14
A multilayer heat insulating material suitable for use in heating furnaces in which a non-oxidizing atmosphere is used, which insulating material comprises a sheet of carbon fiber felt having gas permeability, and a sheet of graphite having a thickness less than 1 mm. and a density of 0.6 to 1.6 grams/cm.sup.3, bonded to at least one surface of the sheet of carbon fiber felt by means of a carbonaceous binder, the density of said graphite sheet being substantially greater than that of said felt sheet.
A process for producing a heat insulating material which comprises steps of:
- (1) forming a multi-layer structure comprising:
- (a) a sheet of gas permeable carbon felt having a bulk density of from 0.06 to 0.10 grams/cm.sup.3 and a compressibility such that the force required to compress the felt sheet to twice said bulk density is from 100 to 200 g/cm.sup.2 and
- (b) a sheet of graphite adjacent at least one surface of said carbon fiber felt, and
- (c) interposed between said sheet of graphite and said sheet of carbon fiber felt, a carbonizable resin,
- (2) hardening the carbonizable resin while applying a pressure of from 50 to 300 grams/cm.sup.3 at the interface between said graphite sheet and said carbon fiber felt and
- (3) carbonizing said carbonizable resin to form said heat insulating material, material having a bonded multi-layer structure.
Dependencies are inferred from the claim text.