Water-retaining polycarboxylic acid slump retaining agent and preparation method thereof

The invention relates to a water-retaining polycarboxylic acid slump retaining agent, which is prepared from the following raw materials in parts by weight: 300 to 400 parts of isopentenyl polyoxyethylene ether, 2 to 20 parts of unsaturated water-retaining functional monomer, 25 to 50 parts of unsaturated acid, 2 to 15 parts of unsaturated acid ester, 2 to 8 parts of oxidizing agent, 0.8 to 2.0 parts of chain transfer agent, 0.1 to 1.0 part of reducing agent, 300 to 760 parts of water and 5 to 20 parts of alkali liquor, the unsaturated water retention type functional monomer is prepared from the following raw materials in parts by weight: 20 to 30 parts of konjac glucomannan, 2 to 20 parts of maleic anhydride, 0.2 to 0.5 part of catalyst and 200 parts of water; the structural general formula of the konjac glucomannan is (C6H10O5) n, wherein n is 2-10. Under the synergistic effect of various groups, the water retention type polycarboxylic acid slump retaining agent prepared by the preparation method disclosed