Method for polymerisation of (meth)acrylic acid in solution, polymer solutions obtained and their uses

摘要

The present invention relates to a new solvent-free preparation method of a (meth)acrylic acid polymer in solution, where said polymer has a molecular weight less than 8,000 g/mol and a polydispersity IP index between 2 and 3 by radical polymerization, the polymers obtained by this means, and their applications in industry.

主权项

1. An aqueous solution comprising water and a (meth)acrylic acid polymer, wherein:
said (meth)acrylic acid polymer has a molecular weight of less than 8,000 g/mol and a polydispersity IP index of 2-3, said solution comprises a molar percentage (mol/mol) of sulphurous polymers of (meth)acrylic acid that is less than 0.1% based on the total amount of (meth)acrylic acid polymer, as measured by RMN, and said aqueous solution is prepared by a method for the organic solvent-free preparation of a (meth)acrylic acid polymer in solution comprising: a) introducing water, and optionally a water-soluble metal salt-based catalyst, into a synthesis reactor, b) heating the synthesis reactor to a temperature of at least 60° C., c) continuously and simultaneously introducing into the reactor:
b1) a (meth)acrylic acid monomer,b2) a compound of formula (I): wherein:
X represents Na, K or H, andR represents an alkyl chain having from 1 to 5 carbon atoms, andb3) a polymerisation initiator, where the mass percentage (weight/weight) between the compound of formula (I) and the (meth)acrylic acid monomer is 0.1-2.5%.