Use of polyester resins for the production of articles having good properties as barriers to water vapor

The present invention relates to the use of biodegradable polyester resins in the production of formed articles having good properties as barriers to water vapour. Polyester resins formed by recurring units X=[O-(CH)-OCO-(CH)-CO] and/or Y=[O-(CH)-CO], where the half-sum of n+m is equal to or greater than 6 and k is a number equal to or greater than 6, or by copolymers comprising units and/or sequences having the formula x[O-(CH)-OCO-(CH)-CO]; y[O-(CH)-CO] where: i,j=1-5; n=2-22; m=0-20; k=1=21; (Formula (1)) and xand yvary between 0 and 1 and are molar fractions of the various units such that (Formula (2)), are used for the preparation of products in which a permeability to water vapour of less than 350 g×30 m/mper day, measured at 38° C. and 90% RH and good biodegradability are required.