| 摘要 |
Latex is prepared by reacting 30-90 wt.% ethylenically unsaturated monomer(s), 70-10 wt.% diene, 1-10 wt.% alpha ,beta -unsaturated carboxylic acids, carboxylic acid nitriles and/or carboxylic acid amides, and at least one auxiliary and/or additive(s). Preparation of latex includes reacting 30-90 wt.% ethylenically unsaturated monomer(s), 70-10 wt.% diene, 1-10 wt.% alpha ,beta -unsaturated carboxylic acids, carboxylic acid nitriles and/or carboxylic acid amides, and at least one auxiliary and/or additive(s). The sum of ethylenically unsaturated monomer, diene and the above carboxylic is 100 wt.%. The ethylenically unsaturated monomer is different from diene and different from the above carboxylic. The reacting step follows a gradient regime for the ethylenically unsaturated monomer and the diene. In the gradient regime, an amount added per unit time of the ethylenically unsaturated monomer or diene continuously increases, while simultaneously an amount added per unit time continuously decreases for the ethylenically unsaturated monomer or diene that does not undergo the continuous increase. Provided that a starting molar ratio of ethylenically unsaturated monomer to diene is adjusted from 0.15-0.95 or 1.05-6.66 through discontinuous change(s) in the amount added per unit time to a target molar ratio of ethylenically unsaturated monomer to diene, in 1.05-6.66 or 0.15-0.95. Then, the change in the amount added per unit time is made constantly for the ethylenically unsaturated monomer and the diene, and/or decreasingly for the ethylenically unsaturated monomer and ascendingly for the diene, and/or decreasingly for the diene and ascendingly for the diene, in any sequence, individually or in combination. |
