▎ 摘　　要

NOVELTY - Low-density composite electromagnetic shielding plate comprises two composite shielding layers and an electromagnetic wave absorbing foam layer. The electromagnetic wave-absorbing foam layer is arranged between the two composite shield layers. The composite shielding layer, the electromagnetic wave absorption foam layer and the other composite shield layer are sequentially stacked to form a low density composite electromagnetic shield plate, where the composite shield comprises multiple glass fiber reinforced epoxy resin insulating layers and graphene conductive shielding layers, the glass fiber-reinforced epoxy insulating layer and a number of graphene -conductive shielding layer are alternately stacked, and the outer surface of both sides. The coating layer comprises components: 50 pts. wt. conductive carbon black, 10 pts. wt. graphene powder, 40 pts. wt. epoxy resin and 50 pts. wt. diluent. USE - The low density composite electromagnetic shielding plate is used in electronic product technology. Uses include but are not limited to mobile phone, personal digital assistant (PDA), portable multimedia player (PMP), digital camera, digital video camera (DVC), digital video recorder (DVR), digital photo frame (DPMR), and personal computer (PC). ADVANTAGE - The low-density composite electromagnetic shielding plate: adopts a glass fiber reinforced epoxy resin insulating layer, a graphene conductive shielding layer and an electromagnetic wave absorbing foam layer to be stacked and connected according to preset rules to form a low-density composite board capable of realizing electromagnetic shielding. DETAILED DESCRIPTION - Low-density composite electromagnetic shielding plate comprises two composite shielding layers and an electromagnetic wave absorbing foam layer. The electromagnetic wave-absorbing foam layer is arranged between the two composite shield layers. The composite shielding layer, the electromagnetic wave absorption foam layer and the other composite shield layer are sequentially stacked to form a low density composite electromagnetic shield plate, where the composite shield comprises multiple glass fiber reinforced epoxy resin insulating layers and graphene conductive shielding layers, the glass fiber-reinforced epoxy insulating layer and a number of graphene -conductive shielding layer are alternately stacked, and the outer surface of both sides. The electromagnetic wave absorbing foam layer includes 60-90 pts. wt. polyether polyol, 10-40 pts. wt. polyester polyol, 1.0-2.5 pts. wt. chemical foaming agent, 10-20 pts. wt. physical foaming agent, 1.0-2.5 pts. wt. catalyst, 1.0-2.0 pts. wt. foam stabilizer, 10-30 pts. wt. conductive carbon black and 80-150 pts. wt. polyisocyanate. The glass fiber-reinforced epoxy resin insulation layer includes an electronic-grade alkali-free glass fiber cloth and an epoxy resin glue layer, and the epoxy resin glue layer is wrapped on the surface of the electronic-grade alkali-free glass fiber cloth. The epoxy resin glue layer includes components 50-80 pts. wt. flame-retardant modified bisphenol A epoxy resin, 20-50 pts. wt. flame-retardant modified solid bisphenol A epoxy resin, 2-6 pts. wt. latent curing agent, 0.01-0.5 pts. wt. curing accelerator, 40-60 pts. wt. organic solvent and 50-100 pts. wt. inorganic filler. The graphene conductive shielding layer includes a glass fiber reinforced epoxy resin insulation layer and a coating layer, and the coating layer is wrapped on the outer surface of the glass fiber reinforced epoxy resin insulation layer. The coating layer comprises components: 50 pts. wt. conductive carbon black, 10 pts. wt. graphene powder, 40 pts. wt. epoxy resin and 50 pts. wt. diluent.. An INDEPENDENT CLAIM is also included for a method for preparing low density composite electromagnetic shielding plate comprising (1) preparing the glass fiber reinforced epoxy resin insulating layer, (2) preparing the graphene shielding layer, (3) preparing the electromagnetic wave absorbing foam layer, (4) orderly and alternately stacking many glass fibers enhanced epoxy resin insulating layer and many graphene conductive shielding layer, so as to form a multi-layer composite structure with two side surfaces of the glass fiber layer of the enhanced epoxy resin, so as to form the composite shielding layer by hot pressing and solidifying, forming a sealed insulating, (5) setting two composite shielding layer on the upper and lower two surfaces of the predetermined mold, and injecting the mixed raw material of the electromagnetic wave absorbing foam layer in the mold, the electromagnetic film foam absorbing layer between the two sides of the composite shielding layer and the two is cooled and shaped in the mold to form the low density composite electromagnetic shielding plate, and (7) cutting and modifying the cooled and shaped low-density composite electromagnetic shielding plate to obtain the finished product of the low-density composite electromagnetic shielding plate.