反应详情

First of all, 310 g of ion-exchanged water and 400 g of maleic anhydride (473.7 g as maleic acid) were charged into a SUS-made separable flask of 5 liters in capacity as fitted with a reflux condenser, a stirrer, and a thermometer. Thereto, 708.3 g of 48 wt % aqueous sodium hydroxide solution (hereinafter referred to as 48%NaOHaq) was gradually added under stirring, so that the initial neutralization degree was 85 mol %, and that the initial solid component concentration was 50.9 wt %. Thereafter, while being stirred, the aqueous solution in the flask was heated to its boiling point under normal pressure. Next, under stirring, 450 g of 80 wt % aqueous acrylic acid solution (hereinafter referred to as 80%AAaq), 114.3 g of 35 wt % aqueous hydrogen peroxide solution (hereinafter referred to as 35%H2O2aq), 166.7 g of 15 wt % aqueous sodium persulfate solution (hereinafter referred to as 15%NaPSaq), and 33.3 g of ion-exchanged water were dropped from different nozzles respectively as follows: 80%AAaq was dropped over a period of 120 minutes; 35%H2O2aq was dropped over a period of 50 minutes starting at the same time with the dropping of 80%AAaq; 15%NaPSaq and ion-exchanged water were dropped over a period of 80 minutes since the dropping end of 35%H2O2aq, namely, starting 50 minutes later than the dropping start of 80%AAaq, and ending 10 minutes later than the dropping end of 80%AAaq. After the dropping end of all components, the reaction solution was kept in a boiling point reflux state for another 20 minutes to complete the polymerization, thus obtaining an acrylic acid-maleic acid copolymer (salt) having a neutralization degree of 64.5 mol % and a solid component concentration of 50 wt % at the end of the polymerization. Thereafter, the pH of this acrylic acid-maleic acid copolymer (salt) was adjusted to 8 with a 48 wt % aqueous NaOH solution.

1. customas fitted with a reflux condenser, a stirrer
2. additionwas gradually added
3. stirringThereafter, while being stirred
4. temperaturethe aqueous solution in the flask was heated to its boiling point under normal pressure
5. stirringNext, under stirring
6. additionwere dropped from different nozzles respectively
7. addition80%AAaq was dropped over a period of 120 minutes
8. addition35%H2O2aq was dropped over a period of 50 minutes
9. waitending 10 minutes later than the dropping end of 80%AAaq
10. temperaturereflux state for another 20 minutes
11. customthe polymerization