Abstract: The present disclosure relates to the technical field of unmanned aerial vehicles, and in particular to a wireless following device and an unmanned aerial vehicle. The wireless following device includes a wireless receiver and a wireless transmitter and further includes a signal guide member for limiting a received signal range of the wireless receiver. The signal guide member is arranged on a front side of the wireless receiver and is provided with a signal guide channel. An inner opening of the signal guide channel faces the wireless receiver, and an outer opening of the signal guide channel faces outside; or/and, a transmitting terminal of the wireless transmitter is connected to a signal limiting member for limiting a wireless signal transmitting range.

Abstract: The present invention provides an efficient halogen-free flame retardant masterbatch for polypropylene, which comprises following raw materials in percentage by weight: 30˜40% of ammonium polyphosphate; 10˜20% of pentaerythritol phosphate; 15˜25% of melamine; 5˜15% of bisphenol A bis(diphenyl phosphate); 10˜30% of microporous polypropylene; 0.1˜1% of pentaerythritol stearate; 0.1˜0.5% of antioxidant 1010; and 0.1˜0.5% of antioxidant 168. Said microporous polypropylene is particles with a size of 3˜5 mm, cell size on a surface of the particle is 10˜100 ?m, and cell density is more than 105 cells/cm3. The efficient halogen-free flame retardant masterbatch for polypropylene prepared by the invention has several characteristics of easy dispersing, easy processing, high flame retardant efficiency and low production cost, and it can be widely used in the production of flame retardant polypropylene materials for extrusion, injection molding and membrane blowing.

Abstract: The present invention provides an efficient halogen-free flame retardant masterbatch for polypropylene, which comprises following raw materials in percentage by weight: 30˜40% of ammonium polyphosphate; 10˜20% of pentaerythritol phosphate; 15˜25% of melamine; 5˜15% of bisphenol A bis(diphenyl phosphate); 10˜30% of microporous polypropylene; 0.1˜1% of pentaerythritol stearate; 0.1˜0.5% of antioxidant 1010; and 0.1˜0.5% of antioxidant 168. Said microporous polypropylene is particles with a size of 3˜5 mm, cell size on a surface of the particle is 10˜100 ?m, and cell density is more than 105 cells/cm3. The efficient halogen-free flame retardant masterbatch for polypropylene prepared by the invention has several characteristics of easy dispersing, easy processing, high flame retardant efficiency and low production cost, and it can be widely used in the production of flame retardant polypropylene materials for extrusion, injection molding and membrane blowing.