▎ 摘　　要

NOVELTY - Preparing graphene fiber comprises (i) selecting and mixing multilayer graphene powder and carbon nanotube powder; (ii) filtering the mixture B to obtain a solid mixture C and adding binder, dispersing agent, plasticizer, drying agent and filler to the mixture C and simultaneously stirring at a speed of 1000-2000 revolutions/minute for 20-40 minutes to obtain a mixture D, adding binder, dispersing agent, plasticizer and drying agent in an amount of 1-1.2 wt.% of the mixture C, adding 20-40 wt.% filler of the mixture C, where the filler has a particle size of 1-5 nm; (iii) grinding mixture D for 20-40 minutes, to obtain a mixture E; (iv) mixing the mixture E with deionized water at a mass ratio of 1:(1-5) to obtain a mixture F; (v) immersing yarn in mixture F for 5-10 minutes, taking out yarn from the mixture F and drying for 5-10 minutes; (vi) scraping off the excess mixture F on yarn which has been hang-dried; and (vii) drying the yarn processed by the step (vi) for 15-20 minutes. USE - The method is useful for preparing graphene fiber. ADVANTAGE - The graphene fiber has fast heat generation, good uniformity and high heat generation efficiency. DETAILED DESCRIPTION - Preparing graphene fiber comprises (i) selecting and mixing multilayer graphene powder and carbon nanotube powder by a mass ratio of 1:(1-5) to obtain a mixture A, immersing the mixture A into a surfactant for 20-40 minutes to obtain a mixture B, where the number of layers of the multilayer graphene powder is greater than 10, the thickness of the multilayer graphene powder is less than 10 nm and horizontal width in the range of 10-15 nm, the carbon nanotube powder has a particle size of 5-10 nm; (ii) filtering the mixture B to obtain a solid mixture C and adding binder, dispersing agent, plasticizer, drying agent and filler to the mixture C and simultaneously stirring at a speed of 1000-2000 revolutions/minute for 20-40 minutes to obtain a mixture D, adding binder, dispersing agent, plasticizer and drying agent in an amount of 1-1.2 wt.% of the mixture C, adding 20-40 wt.% filler of the mixture C, where the filler has a particle size of 1-5 nm; (iii) grinding mixture D for 20-40 minutes, to obtain a mixture E; (iv) mixing the mixture E with deionized water at a mass ratio of 1:(1-5) to obtain a mixture F; (v) immersing the yarn in the mixture F for 5-10 minutes, taking out the yarn from the mixture F and drying for 5-10 minutes; (vi) scraping off the excess mixture F on the yarn which has been hang-dried; and (vii) drying the yarn processed by the step (vi) for 15-20 minutes. INDEPENDENT CLAIMS are also included for: electric heating warm plate; and # fabricating an electric heating warm plate comprising (a) mixing carbon fibers with the graphene fibers to obtain a heat conducting wire; (b) preparing a cover shell and leaving a wiring hole on the cover shell; (c) insulating the inner wall of the covering case; (d) placing the heat conducting wire in the covering case processed by step (c) and connecting the overheat protector in series with the heat conducting wire and connecting both ends of the heat conducting wire with the power connecting wire and extending out the power cable of the covering case; (e) wrapping the material with small thermal conductivity outside the covering shell to form a thermal insulation layer; (f) extruding urethane resin into the cover casing and curing the polyurethane resin and urethane resin, the heat conductive wire and the cover casing form a heat generating layer; (g) connecting the power cable in step (d) to the plug; (h) bonding the insulating material to the heat generating layer of the intermediate product obtained in the step (g) to form an insulating layer; and (i) bonding the wear-resistant material to the insulating layer of the intermediate product obtained in the step (h) to form a covering layer.