Copolymers, their process of preparation, and cosmetic compounds containing them

Copolymers characterized by the fact that they correspond to the following general formula:

• ##STR11## where:
• B represents Na, K, NH.sub.4, ##STR12## or 2-amino-2-methyl propanal-1 R.sub.1 and R.sub.2, identical or different, represent an atom of hydrogen or the radical--(X)--OH;
• X represents an alkylene radical, branched or unbranched, having from 1 to 3 atoms of carbon or an alkylene radical, branched or unbranched, substituted by at least one hydroxymethyl radical;
• M represents a type of at least one unsaturated monomer taken from the group consisting of the acrylamides or methacrylamides substituted on the nitrogen by an alkyl radical, branched or unbranched, the acrylates or methacrylates of monoalkyl ether of ethylene glycol or of polyethylene glycol, and N-vinylpyrrolidone;
• x is from 22% to 64% in moles,
• y is from 13% to 71% in moles,
• z is from 6% to 23% in moles, and
• v is from 0% to 22% in moles,
• x+y+z+v being equal to 100%.