REUSABLE WRITING PAPER MATERIAL AND POLYMER-BASED COMPOSITION FOR CLEANING THIS MATERIAL Russian patent published in 1995 - IPC

FIELD: drawing and office accessories. SUBSTANCE: polystyrene sheet with the thickness of 0.8-1.5 mm of opal, white, light-green, light-pink, light-blue color with matted surface is used as reusable writing paper material for writing by pencil. Composition used for removal of pencil inscriptions from writing paper material consists, % by weight:polymethylmethacrylate - 1.23%, glycerine - 8.20%, potash alums - 0.16%, ethyl alcohol - 8,20%, perfumery odorant 0.0082%, distilled water the balance. Writing paper material is characterized in that it allows about 20000 inscriptions to be made and rubbed-off without visible deterioration of contrast between written material and basic material. As a result consumption of paper for pupil's, student's, office and like inscriptions is reduced by 7000 times and usage of power resources and wood is considerably decreased. Material- base and cleaning composition-are non-toxic, satisfy strict hygiene requirements, may be used many times, and is manufactured from chemical industry wastes. EFFECT: increased efficiency by reduced usage of paper, power and wood, increased economy by manufacturing this material from wastes and decreased contamination of environment by using non-toxic materials. 3 cl