19  US 6,930,141 B2  20  A  monomer emulsion was prepared by combining 969 g  of  BA,  34 g of  MAA,  680 g of  MMA,  460 g  DI  water, and  18.7 g Triton™ XN-45S surfactant (Triton is a trademark of  Union Carbide Co.), and emulsifying with stirring. Next, 2.5  g Triton™ XN-45S surfactant and 1000 g DI water were  charged to a five liter multi-neck flask fitted with mechanical  stirring. The contents of the flask was heated to 85°  C. under  a nitrogen atmosphere. To the stirred flask contents were  added 92 g the monomer emulsion followed by 2.6 g  APS  in 100 g  DI  water and followed by 1.7 g sodium carbonate  in 100 g DI water. Next, 34 g of a 50% solution of ureido  methacrylate was added to the remainder of the monomer  emulsion and the gradual addition of the monomer emulsion  An aqueous dispersion containing comparative soft poly› mer particles was prepared by a polymer process that did not  include redox polymerization.  Preparation of an Aqueous Dispersion Containing  Comparative Soft Polymer Particles  An aqueous dispersion containing the soft polymer par- tides is prepared by a thermally initiated controlled conver- sion process.  Preparation of an Aqueous Dispersion Containing  Soft Polymer Particles  Example 1 was prepared by a polymerization process  wherein at least 40% of the weight of the soft polymer  particles were prepared by a redox polymerization. Further,  the soft polymer particles of Example 1 were formed in a  process wherein at least 40 weight % of each of the soft  polymer particles were polymerization in the presence of  excess unreacted monomer.  The resulting aqueous dispersion, Example 1, contained  49.2 weight % soft polymer particles, based on the total  weight of Example 1. The soft polymer particles had an  average particle diameter of 187 nm and a glass transition  temperature of -10°  C.  The resulting aqueous dispersion, Example 2, contains  50.2% by weight of the soft polymer particles, based on the  total weight of Example 2. The soft polymer particles have  an average particle diameter of 169 nm and a glass transition  temperature of 5°  C.  The % conversion of the monomer in the reaction mixture  during the addition of the monomer emulsion is shown in  Table 1.2.  The % conversion of the monomer in the reaction mixture  during the addition of the monomer emulsion is shown in  Table 2.2.  A  monomer emulsion was prepared by combining 600 g  BA,  20 g  MAA,  365 g  MMA,  1.25 g  nDDM,  400 g  DI  water,  6.9 g sodium carbonate and 30.5 g  SLS  and emulsifying with  stirring. Next, 5.2 g  SLS  and 380 g  DI  water were charged  to a three liter multi-neck flask fitted with mechanical  stirring. The flask contents were heated to 65°  C. under a  nitrogen atmosphere. To the stirred flask contents were  added 35 g of the monomer emulsion followed by 0.02 g  ferrous sulfate heptahydrate and 0.02 g tetrasodium salt of  ethylenediamine-tetraacetic acid in 15.6 g  DI  water. Poly› merization was initiated by the addition of 0.54 g  APS  in 8  g  DI  water followed by 0.27 g sodium hydrosulfite in 8 g  DI  water. Next, 30 g of a 50% solution of ureido methacrylate  was added to the remainder of the monomer emulsion and  gradual addition of the monomer emulsion was subsequently  initiated. Separate solutions of 2.9 g  APS  in 50 g  DI  water  and 1 g of D-isoascorbic acid in 50 g  DI  water were fed  concurrently with the monomer emulsion. Total addition  time for the three feeds was 90---100 minutes. The contents  of the flask was maintained at 65°  C. throughout the addition  of the monomer emulsion. The emulsion feed line was  rinsed with 20 g DI water. After completion of the monomer  emulsion addition, the reactor was cooled to 60°  C. Next, an  aqueous solution containing 10 ppm ferrous sulfate, 1 g  t-butyl hydroperoxide and 0.5 g D-isoascorbic acid was  added. The contents of the flask was neutralized to a pH in  the range of 9-10 with ammonium hydroxide.  A  monomer emulsion is prepared by combining 480 g  MMA,  500 g  BA,  20 g  MAA,  1.25 g  nDDM,  455 g  DI  water,  and 30.5 g  SLS  and emulsifying with stirring. Next, 5.2 g  SLS  and 215 g  DI  water are charged to a three liter  multi-neck flask fitted with mechanical stirring. The con› tents of the flask is heated to 88° C. under a nitrogen  atmosphere. To the stirred flask contents, 35 g of the  monomer emulsion is added followed by a solution contain› ing 0.35 g sodium carbonate and 0.3 gAPS in 20 g DI water.  Next, the monomer emulsion is gradually added to the flask  along with the concurrent addition of an initiator solution  containing 1.05 g APS and 6.55 g sodium carbonate in 50 g  DI water. The total addition time for the feeds is approxi› mately 90---100 minutes. Throughout the addition of the  monomer emulsion, the contents of the flask is maintained  at a temperature of 88°  C. After the complete addition of the  monomer emulsion and the initiator solution, the emulsion  feed line is rinsed with 20 g DI water, which is added to the  flask. Next, the contents of the flask is cooled to approxi- mately 60°  C. and an aqueous solution containing 10 ppm  ferrous sulfate, 1 g t-butyl hydroperoxide and 0.5 g  D-isoascorbic acid is added. The contents of the flask is  neutralized to a pH in the range of 9-10 with ammonium  hydroxide.  An  aqueous dispersion containing the soft polymer par› ticles was prepared by redox polymerization.  EXAMPLE 1  Preparation of an Aqueous Dispersion Containing  Soft Polymer Particles  TABLE 2.2  TABLE  1.2  COMPARATIVE A  %  Conversion of Monomer in the Polymerization of Example 2  weight% of  weight % polymer  weight % unreacted  monomer feed  formed  added monomer  20  88  12  40  87  13  60  89  11  80  91  9  90  92  8  100  93  7  %  Conversion of Monomer in the Polymerization of Example 1  weight% of  weight % polymer  weight % unreacted  monomer feed  formed  added monomer  20  86.2  13.8  40  88.3  11.7  60  89.5  10.5  80  90.8  9.2  90  92.5  7.5  100  90.6  9.4  EXAMPLE 2 