Abstract: A thermoplastic methacrylimide group-containing resin composition comprised of (a) a methacrylimide group-containing polymer comprising 5 to 100% by weight of units of an imide ring structure represented by the following structural formula (I): ##STR1## wherein R.sub.1 stands for a hydrogen atom, a substituted or unsubstituted alkyl, cycloalkyl, aryl, alkaryl, aralkyl or allyl group having 1 to 20 carbon atoms,and 0 to 95% by weight of units derived from at least one monoethylenically unsaturated monomer, and (b) a small amount of a tetramethylpiperidine derivative is described. A shaped article made from this composition has a highly improved weatherability.

Abstract: A thermoplastic resin composition comprising 0.01 to 10 parts by weight of at least one ultraviolet ray absorbent having a peak absorption wavelength at 240-300 nm in the range of 240-400 nm and 100 parts by weight of methacrylimide group-containing polymer containing at least 5% by weight of imide ring structural unit expressed by the following structural formula is disclosed: ##STR1## (wherein R.sub.1 is a hydrogen atom, or a substituted or non-substituted alkyl group having 1-20 carbon atoms, cycloalkyl group, aryl group, alkalyl group, alalkyl group, or allyl group.)This composition has an improved weather durability and thermal resistance as well as light transmittance.