Mixtures and concentrates for the preparation of polymers

A method of preparing a concentrate for a gel of a neutralized cross-linked polymer of a polymerisable olefinically unsaturated carboxylic acid, the method comprising the step of:

• mixing together a premix of the polymer in the acid form and a salt of a multivalent cation with water, the salt being present in an amount of from 0.002 to 0.2 equivalent of the multivalent cation per equivalent of the acid groups of the polymer.

A method of preparing a concentrate for a gel of a neutralized cross-linked polymer of a polymerisable olefinically unsaturated carboxylic acid, the method comprising the step of:

• mixing together a premix of water and a salt of a multivalent cation with the polymer in the acid form, the salt being present in an amount of from 0.002 to 0.2 equivalent of the multivalent cation per equivalent of the acid groups of the polymer.

A premix for preparing a concentrate for a gel of a neutralized cross-linked polymer of a polymerisable olefinically unsaturated carboxylic acid, the premix comprising a dry mixture of the polymer in the acid form and a salt of a multivalent cation, the salt being present in an amount of from 0.002 to 0.2 equivalent of the multivalent cation per equivalent of the acid groups of the polymer.

A dry polymer preparation comprising:

• a cross-linked polymer of a polymerisable olefinically unsaturated carboxylic acid, the unsaturated carboxylic acid constituting at least 70% by weight of the polymer and the polymer being cross-linked with a multifunctional vinylidene compound containing at least two terminal CH.sub.2 =C<groups and being in the acid form;
• and
• a salt of a multivalent cation in an amount of from 0.002 to 0.2 equivalent of multivalent cation per equivalent of the acid groups of the polymer.