PURPOSE: To provide secure adhesion between a magnetic layer and a base and improve holding property to magnetic particles and the resilience of the magnetic layer itself by using a specified electron ray curable binder for a magnetic recording material in the form of the mixture composed of resins having the same molecular structure but having the different mol. wt. over the entire part.
CONSTITUTION: An acryl modified polyurethane resin used as an electron curable binder for a magnetic layer is expressed representatively by the general formula. The polyester part here is the reaction product of, for example, 1,4-butandiol and adipic acid and the reaction product of propylene glycol and adipic acid, and said products having ≤500mol.wt. (more preferable 300W500 range) are used. The mol. wt. over the entire part of the molecular structure in the mixed system binder is required to be 20,000W30,000 (component A), 8,000W10,000 (component B) and 1,500W3,000 (component C). The mixing ratio of the three kinds is ≤20pts.wt., more preferably 15W20pts.wt. the component B and ≤10pts.wt., more preferably 3W10pts.wt. in 100pts.wt. the component A.
NARUSE SHIYOU
ICHIKAWA AKIRA
KATOU KAZUO
