Patent ID: 7101927

Claim:
A latex obtained by reacting A) 30–90% by weight of at least one ethylenically unsaturated monomer; B) 70–10% by weight of a diene; C) 1–10% by weight of α,β-unsaturated carboxylic acids, carboxylic acid nitriles, carboxylic acid amides, esters of C 3 to C 6 α,β-monoethylenically unsaturated monocarboxylic acids with C 1 to C 12 alkanols, esters of C 3 to C 6 α,β-monoethylenically unsaturated dicarboxylic acids with C 1 to C 12 alkanols, anhydrides of C 3 to C 6 α,β-monoethylenically unsaturated monocarboxylic acids, anhydrides of C 3 to C 6 α,β-monoethylenically unsaturated dicarboxylic acids or mixtures thereof; and D) at least one of an auxiliary and an additive; wherein % by weight is based on the total weight of A, B and C; wherein said reacting follows a gradient regime for components A and B; wherein, in said gradient regime, an amount added per unit time of one of components A or B continuously increases, while simultaneously an amount added per unit time continuously decreases for one of components A or B which does not undergo the continuous increase; with the proviso that a starting molar ratio of A to B is adjusted from a range of 0.15–0.95 or 1.05–6.66 through at least one discontinuous change in the amount added per unit time to a target molar ratio of A to B, in the range of 1.05–6.66 or 0.15–0.95, and thereafter the change in the amount added per unit time is made i) constantly for A and B, and/or ii) decreasingly for A and ascendingly for B, and/or iii) decreasingly for B and ascendingly for A, in any sequence, individually or in combination.