Polymer composition and a method for producing the same

The present invention relates to powdered, crosslinked polymer compositions, containing

a) 55-99.9 wt.-% of at least one polymerized, ethylenically unsaturated, polymerizable monomer which contains acid groups neutralized to at least 25 mole-%,

b) 0-40 wt.-% of polymerized, unsaturated monomers copolymerizable with a),

c) 0.01-5.0 wt.-%, preferably 0.1-2.0 wt.-% of one or more crosslinking agents,

d) 0-30 wt.-% of a water-soluble polymer,

the weight amounts a) through d) being based on anhydrous polymer composition, and the sum of these components always being 100 wt.-%, which compositions can be obtained by continuous polymerization wherein at least one parameter biasing the polymerization is varied according to a recurring pattern. The present invention also relates to a process for their production and to their use.