▎ 摘　　要

NOVELTY - A heating film comprises several layers of graphene and carbon fibers comprising 0.1-5 pts. wt. graphene and 60-80 pts. wt. carbon fibers, 3-5 pts. wt. bamboo pulp, 0.5-1 pts. wt. dispersant, 0.2-0.5 pts. wt. coupling agent, and 1-3 pts. wt. defoaming agent, 3-5 pts. wt. negative oxygen ion powder, 2-5 pts. wt. tin oxide, 1-3 pts. wt. antioxidant, 0.1-1 pts. wt. penetrant, 1-2 pts. wt. silica, 1-10 pts. wt. flame retardant, and 1-3 pts. wt. reinforced strength and toughness material chosen from polyvinyl alcohol, polyimide, polyvinyl alcohol or polyimide or Hot melt polypropylene fiber reinforcement film. USE - Heating film is used for preparing device e.g. floor heating device and composite agricultural mulching heating device (all claimed). ADVANTAGE - The heating film has high safety, reliability, uniqueness and practicality, as compared to usual metal heating film, and can achieve energy saving of more than 30%. The film is not easy to oxidize, and has a life decay rate of 1.7% and a heat utilization rate of 99.8%. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) preparation of heating film, which involves adding 50-60 pts. wt. carbon fibers and 30-50 pts. wt. bamboo pulp, adding 0.1-1 pts. wt. thickener and 0.5-1 pts. wt. dispersant, stirring at 800-1200 rpm and at 35-40 degrees C, stirring at 200 rpm for 1-2 hours, adding 0.2-0.5 pts. wt. coupling agent and stirring well to improve the interface fusion between the two phases and improve the surface strength of the finished product, adding defoaming agent and stirring to quickly remove the bubbles in the slurry to obtain a carbon fiber substrate slurry, adding 1-2 pts. wt. graphene solvent, preferably polyvinylpyrrolidone or water into a stirring device, adding 0.1-5 pts. wt. graphene and stirring to obtain a graphene slurry, adding 10-20 pts. wt. carbon fiber powder and 1-3 pts. wt. reinforced strength and toughness material, adding 1-2 pts. wt. silica and 0.1-1 pts. wt. penetrant, adding water and diluting to obtain a carbon fiber slurry, adding 3-5 pts. wt. negative oxygen ion powder, 2-5 pts. wt. tin oxide, adding 1-10 pts. wt. flame retardant, 0.1-1.0 penetrant, 1-3 antioxidant, and mixing to obtain a negative oxygen ion powder slurry having a viscosity of 50-60 cps, ultrasonically-mixing the graphene slurry, the carbon fiber slurry and negative oxygen ion powder slurry and horizontally sand-milling, filtering through a bag filter having a pore size of 1-5 mu m at a filtration pressure is 1-1.5 kg/cm2to obtain a sprayed mixed slurry with a fineness of less than 5 mu m, transferring on the carbon fiber substrate slurry at a speed of 10-15 m/minute to form a conductive heat-generating base film, semi-drying, spraying the slurry in the form of mist spraying, drying, calendering, cooling, performing slitting treatment, drying and pressurizing for surface calendering treatment by a steam drying device, cooling, and cutting raw edges; (2) device, which comprises the heating film; (3) preparation of floor heating device, which involves fixing two conductive copper foils to opposite end edges of the heating film having a resistance value of 6-15 Omega , pressing to increase the contact area of the conductive copper foil and the heating film, applying a hot-melt adhesive film on both sides of the heating film, pressing using a hot-melt laminating machine. The conductive copper foils are electrodes; and (4) preparation of composite agricultural mulching device, which involves selecting the heating film with a resistance value of 28-38 Omega , cutting the heating film to a width of 50-60 cm, fixing two conductive copper foils on the opposite end edges of the heating film, pressing to increase the contact area of the conductive copper foil and the heating film, applying a hot-melt adhesive film on both sides of the heating film, and pressing using a hot-melt laminating machine, applying a thermoplastic plastic film on two surfaces of the heating film using the hot-melt adhesive film, heating at 120-150 degrees C, curing, stamping the cured film to form a drainage structure which is used to exclude the moisture of the crops growing on the upper portion so as to obtain a composite agricultural mulching film, and covering the upper layer of the composite agricultural mulching film with agricultural planting equipment.