| 摘要 |
PURPOSE:To increase the adhesion between a magnetic layer and a base and to improve durability and wear resistance as well by providing a specific undercoating layer. CONSTITUTION:An undercoating layer (adhesive layer) for which a specific resin curable by electron beam and a thermosetting resin and/or thermoplastic resin are used in combination is provided between a magnetic layer of the type curable by electron and a base. The polyester part of an acryl modified polyurethane resin having penta- or more functional branched molecular structure has the characteristic to improve adhesion to the base. The mol.wt. in this part is preferably n a range of 2,000-4,000 when adhesiveness is considered. The mol. wt. of the entire part of said resin is preferably in a range of 20,000-50,000 and the number of functional groups is in a range of 7-13 in order to provide the flexibility, strength and toughness required for the undercoating layer.
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