Copolymers containing carboxyl groups in aqueous dispersion form or redispersible powder form and their water-soluble salts, processes for their preparation and their use as thickeners in aqueous formulations

A copolymer based on ethylenically unsaturated monomers which can undergo free radical copolymerization, the macromolecules of which contain monomer units carrying carboxyl groups prepared by emulsion copolymerization initiated by free radicals in the presence of water-soluble polyvinyl alcohol (PVAL) or other water-soluble organic protective colloids, and anionic emulsifiers selected from the group consisting of alkyl sulfates, alkyl sulfonates, alkylaryl sulfonates, alkali metal salts and ammonium salts of alkyl and alkylaryl mono and polyglycol ether sulfates or nonionic emulsifiers selected from the group consisting of oxyethylated fatty alcohols and oxyethylated alkylphenols and are in an aqueous dispersion form having a solids content of 10 to 50% by weight or in dried redispersible powder form, and optionally some or all of the carboxyl groups of the copolymer are in a water-soluble salt form, having a thickening and rheology-modifying action in aqueous media, wherein the copolymer comprises, in each case based on the copolymer,

• a) 5 to 15% by weight of constituents comprising water-soluble polyvinyl (PVA) grafted during copolymer formation, or mixtures of at least 50% by weight based on the mixture, of water-soluble PVA grafted during copolymer formation and at lest one of the components selected from the group consisting of:
• 1) a water-soluble cellulose,
• 2) water-soluble polymers of N-vinylamide compounds optionally grafted during copolymer formation,
• 3) water-soluble homopolymeric, copolymeric or block copolymeric polyalkylene oxides and
• 4) water-soluble polyvinyl alcohols modified by isocyanate compounds or acetoacetoxylated, or
• a.sub.1) instead of component a), 5 to 15% by weight of constituents comprising water-soluble polyvinyl-pyrrolidone (PVP) grafted during copolymer formation, and
• b) 24 to 64% by weight of monomer units comprising ethylenically unsaturated monomers carrying carboxyl groups, and
• c) 30 to 69% by weight of monomer units comprising methacrylic acid esters or acrylic acid esters of aliphatic alcohols of 1 to 22 carbon atoms, and
• d) 0.1 to 20% by weight of monomer units comprising ethylenically unsaturated comonomers which differ from components b) and c) and
• e) 0.1 to 15% by weight of monomer units comprising ethylenically unsaturated surface-active comonomers, and
• f) 0.01 to 2% by weight of monomer units comprising polyethylenically unsaturated comonomers, and
• g) 0.1 to 1.5% by weight of molecular weight regulators and the copolymer, in its acid form or its partial salt form, is in the form of an aqueous dispersion or a dried redispersible powder, or when, in its water-soluble partial or complete salt form, is in the form of an aqueous solution or an aqueous gel or a dried water-soluble powder.

A copolymer based on ethylenically unsaturated monomers which can undergo free radical copolymerization, the macromolecules of which contain monomer units carrying carboxyl groups prepared by emulsion copolymerization initiated by free radicals in the presence of water-soluble polyvinyl alcohol (PVAL) or other water-soluble organic protective colloids, and are in an aqueous dispersion form having a solids content of 10 to 50% by weight or in dried redisperible powder form, and optionally some or all of the carboxyl groups of the copolymer are a water-soluble salt form, having a thickening and rheology-modifying action in aqueous media, wherein the copolymer consisting essentially of, in each case based on the copolymer,

• a) 5 to 15% by weight of constituents comprising
• water-soluble polyvinyl alcohol (PVA) grafted during copolymer formation, or mixtures of at least 50% by weight based on the mixture, of water-soluble PVA grafted during copolymer formation, and at least one of the components selected from the group consisting of:
• 1) a water soluble cellulose,
• 2) water-soluble polymers of N-vinylamide compounds optionally grated during copolymer formation,
• 3) water-soluble homopolymeric, copolymeric or block copolymeric polyalkylene oxides and
• 4) water-soluble polyvinyl alcohols modified by isocyanate compounds or acetoacetoxylated, or
• a.sub.1) instead of component a), 5 to 15% by weight of constituents comprising water-soluble polyvinyl-pyrrolidone (PVP) grafted during copolymer formation, and
• b) 24 to 64% by weight of monomer units comprising ethylenically unsaturated monomers carrying carboxyl groups, and
• c) 30 to 69% by weight of monomer units comprising methacrylic acid esters or acrylic acid esters of aliphatic alcohols of 1 to 22 carbon atoms, and
• d) 0.1 to 20% by weight of monomer units comprising ethylenically unsaturated comonomers which differ from components b) and c) and
• e) 0.1 to 15% by weight of monomer units comprising ethylenically unsaturated surface-active comonomers, and
• f) 0.01 to 2% by weight of monomer units comprising polyethylenically unsaturated comonomers, and
• g) 0.1 to 1.5% by weight of molecular weight regulators and the copolymer, in its acid form or its partial salt form, is in the form of an aqueous dispersion or a dried redispersible powder, or when, in its water-soluble partial or complete salt form, is in the form of an aqueous solution or an aqueous gel or a dried water-soluble powder.