Acrylic core shell copolymer, having excellent compatibility in polycarbonate (PC), PBT, and polycarbonate alloys such as PC/ABS, PC/PBT and PC/PET, providing superior toughness performance while maintaining good flexural modulus. The unique acrylic composition, with a glass transition temperature lower than -50℃, leads to good impact performance at very low temperatures. This chemical composition also yields good weatherability and aging stability that surpasses the performance of vinyl rubbers.