VERFAHREN ZUR HERSTELLUNG VON ACRYLSÄURE-POLYMEREN
摘要:
The invention relates to a method for producing aqueous solutions of acrylic acid polymers by polymerizing acrylic acid in feed mode with a radical starter in the presence of hypophosphite in water as a solvent, wherein (i) water and optionally acrylic acid in acidic, non-neutralized form, optionally one or more ethylenically unsaturated comonomers, optionally aqueous hypophosphite solution, and optionally initiator are introduced, (ii) acrylic acid in acidic, non-neutralized form, optionally one or more ethylenically unsaturated comonomers, aqueous radical starter solution, and aqueous hypophosphite solution are added, (iii) after the end of the acrylic acid feed, a base is added to the aqueous solution, wherein the comonomer content does not exceed 30 wt% with respect to the total monomer content, characterized in that the acrylic acid, the aqueous radical starter solution, and the aqueous hypophosphite solution are added in such a way that, over a time period in which at least 75% of the acrylic acid is converted, the molar ratio x of acrylic acid to phosphorus-bonded hydrogen [AA]/[P-H] has a value x that is constant to ±0.5 and that lies in the range of 0.8 to 2.
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