▎ 摘　　要

NOVELTY - A protective cover comprises 42-44 pts. wt. modified polycaprolactone, 26-28 pts. wt. low density polyethylene, 14-18 pts. wt. cellulose diacetate, 16-20 pts. wt. magnesium fluoride, 4-6 pts. wt. toughening agent, 3-5 pts. wt. compatibilizer, 2-6 pts. wt. magnesium stearate powder, 1-3 pts. wt. nano graphene, 1-3 pts. wt. melamine, and 1-2 pts. wt. filler. USE - A protective cover used for mobile phones (claimed). ADVANTAGE - The protective cover has improved strength and mechanical properties, and does not easily degrade thus preventing environmental pollution. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation of the protective cover, comprising: (A) adding modified polycaprolactone, low density polyethylene, and cellulose diacetate in a high-speed stirrer, stirring at 420-520 revolutions/minute (rpm) for 35-45 minutes, reacting at 125-135 degrees C for 1-3 hours to obtain mixture A; (B) adding the mixture A, magnesium fluoride, magnesium stearate powder, and nano graphene in a high speed mixer, uniformly mixing at 460-560 rpm for 45-55 minutes, adding the mixture in a reaction kettle, preserving heat at 115-125 degrees C for 35-45 minutes to obtain mixture C; and (C) placing the mixture C, toughening agent, compatibilizer, melamine, and filler in a three-section heating single-screw extrusion film blowing machine, where the first section has a melting temperature of 165 degrees C, the second and third sections has a melting temperature of 175-185 degrees C, mold temperature is 145-155 degrees C, die orifice gap is less than 1 mm, the rotation speed of the screw is 15-25 rpm, and cooling.