Patent ID: 7977432

Claim:
A carboxylated block copolymer that is solid in water comprising at least two polymer end blocks A and at least one polymer interior block B wherein: a. each A block is a polymer block resistant to lithiation and each B block is a polymer block susceptible to lithiation, said A and B blocks containing no significant levels of olefinic unsaturation; b. each A block independently having a number average molecular weight between 1,000 and 60,000 and each B block independently having a number average molecular weight between 10,000 and 300,000; c. each A block is a segment consisting of one or more polymerized para-substituted styrene monomers; d. each B block comprising segments of one or more vinyl aromatic monomers selected from polymerized (i) unsubstituted styrene monomers, (ii) ortho-substituted styrene monomers, (iii) meta-substituted styrene monomers, (iv) alpha-methylstyrene, (v) para-substituted styrene having hydrogen on a para benzylic carbon center, (vi) 1,1-diphenylethylene, (vii) 1,2-diphenylethylene and (viii) mixtures thereof; e. said B blocks are carboxylated to the extent of 10 to 100 mol percent, based on the units of vinyl aromatic monomer in said B blocks; f. the mol percent of vinyl aromatic monomers which are unsubstituted styrene monomers, ortho-substituted styrene monomers, meta-substituted styrene monomers, alpha-methylstyrene, para-substituted styrene having hydrogen on a para benzylic carbon center, 1,1-diphenylethylene and 1,2-diphenylethylene in each B block being between 10 mol percent and 100 mol percent; and g. said carboxylated block copolymer is solid and non-dispersible in water and has a tensile strength greater than 100 psi in the presence of water according to ASTM D412 after immersion in water for 24 hours.