FIELD: educational equipment. SUBSTANCE: invention deals with multifunctional blackboard for writing with chalk containing chalk panel joined through permanent connection with basis executed from wood fiber material. According to invention, chalk panel is made of elastic material based on polyvinylchloride waste, 70-90 wt %, and rubber compound, 10-30 wt %, and is joined with basis by way of heating elastic material to melting point under pressure. EFFECT: low weight, required hardness of chalk panel, non-expensive starting materials, simplicity and reliability in operation. 2 cl, 2 dwg
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Authors
Dates
1998-01-10—Published
1996-04-02—Filed