Presently described are block copolymers suitable for use as a low adhesion backsize (“LAB”) coating. The block copolymers comprise at least one polyorganosiloxane block and at least one polyolefin block. The polyolefin block is semi-crystalline having a melt point of at least 110° C. The block copolymer typically has the structure: A[-L-B]n wherein A is a polyorganosiloxane block and B is a polyolefin block. L is a covalent bond or a divalent linking group. In some embodiments, L is the reaction product of an amine or hydroxyl and an anhydride.