The invention belongs to the technical field of
papermaking, and particularly relates to multilayer anti-counterfeiting medium frame paper and a preparation method thereof. The invention aims to solve the problems of poor interlayer bonding force and interface separation risk of the current anti-counterfeiting paper. Raw paper is prepared in three
layers through a multi-layer composite technology, the first layer and the third layer use outer layer paper pulp, the second layer uses inner layer paper pulp, and the safety line is embedded into the second layer. Wherein the inner-layer paper pulp comprises
Manila hemp pulp,
polyvinyl alcohol fibers and low-melting-point hot melting fibers; the outer-layer paper pulp comprises short velveteen fibers and high-melting-point hot melting fibers. Wet raw paper prepared by a multi-layer compounding process is subjected to squeezing compounding and step-by-step
drying to obtain raw paper, and the raw paper is further coated with a
composite coating and then subjected to
hot press polishing treatment to obtain the multi-layer anti-counterfeiting medium frame paper. The multilayer anti-counterfeiting medium frame paper prepared by the method is good in interlayer
binding force, excellent in
watermark keeping effect and good in anti-counterfeiting compatibility.