Lithium ion secondary battery electrode binder resin, the composition containing the same and pastes, as well as the lithium ion secondary battery electrode using the same

A binder resin for electrode of lithium ion secondary battery that excels in not only adherences to electrode active-material particles and to metal foil but also capability of holding electrode active-material particles exhibiting large volume expansion/shrinkage upon charging and discharging. The binder resin for electrode of lithium ion secondary battery is composed mainly of at least one structural unit selected from among the structural units represented by any of the following general formulae (1) to (3). When (a) refers to the content of structural units of the general formula (1), (b) to the content of structural units of the generalformula (2) and (c) to the content of structural units of the general formula (3), (a), (b) and (c) satisfy the relationship of formula (A). The binder resin has a logarithmic viscosity of 0.02 to 2.0 dl/g at 30°C. (1) (2) (3)