| abstract |
The object of this invention is to provide a vinyl acetal based polymer, which has sufficient plasticity, solubility to alcohol based solvents, low viscosity and stability of the solution thereof and so on, phase separation from other ingredients does not easily occur, may obtain a slurry excellent in the particle dispersibility or thioxtropic property, or a sheet excellent in strength or flexibility. This invention is related to an alkyl modified vinyl acetal based polymer, which is obtained by performing acetalization of an alkyl modified vinyl alcohol based polymer, the aforementioned alkyl modified vinyl alcohol based polymer containing the monomer unit represented by the following general formula (I), and the viscosity average polymerization degree P of the alkyl modified vinyl alcohol based polymer being above 150 and below 5, 000, the saponification degree being above 20 molar percent and below 99.99 molar percent, the alkyl modification rate S obtained due to the aforementioned monomer unit being above 0.05 molar percent and below 5 molar percent. |