FIELD: polymer production. SUBSTANCE: block copolymers are prepared by anionic polymerization in solution with, in initiation phase, alkali metal-based catalysts deactivating copolymers so that they have terminal alkali metal alcoholate group (-O-Me-). Deactivated copolymer is treated with 0.02-2.0 wt parts of cyclic anhydride of polycarboxylic acid per 100 wt parts of copolymer or with the same amount of mixture of such anhydride with up to 50% of monocarboxylic C2-C4-acid. Product is transparent and resistant to shock. EFFECT: achieved compatibility with foods and improved resistance to water absorbance. 6 cl, 3 tbl
