Elastomer copolyether ester composition for flexible grease

A copolyether ester composition comprising a mixture of at least 2 copolyether esters A and B, wherein each of said copolyether ester A and B is composed of (i) hard segments derived from at least one alkylene diol and at least one aromatic dicarboxylic acid and (ii) soft segments derived from at least one polyalkylene oxide glycol and at least one aromatic dicarboxylic acid, in which the concentrations of soft segments in each of said copolyether esters A and B is between 30 and 65 wt. % relative to the copolyether ester and the molecular weights of the soft segments are between 500 and 3000, wherein the composition is obtained via melt mixing, and wherein the copolyether esters A and B are at least partly unmixed.

A method of preventing premature leakage of lubricant from a product under conditions of dynamic deformation in flexure comprising:

• forming the product from a melt of a composition comprising a mixture of at least 2 copolyether esters A and B, wherein each of said copolyether ester A and B is composed of (i) hard segments derived from at least one alkylene diol and at least one aromatic dicarboxylic acid and (ii) soft segments derived from at least one polyalkylene oxide glycol and at least one aromatic dicarboxylic acid, in which the concentrations of soft segments in each of said copolyether esters A and B is between 30 and 65 wt. % relative to the copolyether ester and the molecular weights of the soft segments are between 500 and 3000.

A method of preventing premature leakage of lubricant from a product under conditions of dynamic deformation in flexure comprising:

• forming the product from a melt of a composition comprising a mixture of at least 2 copolyether esters A and B, composed of hard segments derived from at least one alkylene diol and at least one aromatic dicarboxylic acid and soft segments derived from at least one polyalkylene oxide glycol and at least one aromatic dicarboxylic acid, in which the concentrations of soft segments X in A and soft segments Y in B lie between 30 and 65 wt. % relative to the copolyether ester and the molecular weights of X and Y lie between 500 and 3000 and |Mx−MY|≧400.