MAGNETIC RECORDING MEDIUM

摘要

PURPOSE:To enable high-speed use and repeated use by forming a magnetic layer on one side of a support and a backing layer on the other side and by using polyurea resin having siloxane bonds in the molecule as resin forming the backing layer so as to increase the softening point and to reduce the coefft. of friction. CONSTITUTION:Polyurea resin is synthesized from polysiloxanepolyamine having two or more amino groups in one molecule and a polyisocyanate compound having two or more isocyanate groups in one molecule. Polydi alkylsiloxanediamine having about 500-10,000 average mol.wt. is preferably used as the polysiloxanepolyamine. The polyisocyanate compound is a general polyisocyanate compound such as toluene-2,4-diisocyanate. The synthesis is carried out so as to regulate the amount of silicon atoms in the resulting polyurea resin to about 5-50wt% per 100pts.wt. polyurea rsin. A dispersion contg. the polyurea resin is prepd., applied to a support, and dried to form a backing layer for a magnetic recording medium.