Abstract: A method of manufacturing a roll-type composite sheet including agitating a silicone gel using a mixer; agitating first powder and the silicone gel for 5 to 20 minutes to form a first mixture including at least the first powder and the silicone gel; agitating the first mixture and second powder for 5 to 20 minutes to form a second mixture; adding a solvent at least to the second mixture to form a reaction product being in a form of a paste; removing bubbles from the reaction product; coating the reaction product on a release medium at a temperature of 80 to 140° C.; and curing and drying the reaction product to form the composite sheet.