(10)  Patent No.:  US 6,930,141 B2  (45)  Date of Patent:  Aug. 16, 2005  (12)  United States Patent  Gebhart et al.  (54)  AQUEOUS POLYMER BLEND  COMPOSITION  (75)  Inventors:  Matthew Stewart Gebhart,  New  Britain, PA (US);  Deborah Gay  Fradkin,  Horsham, PA (US);  Bonnie  Elizabeth Baker,  Erdenheim, PA (US);  John Michael Friel,  Warminster, PA  (US);  Steven Scott Edwards,  Horsham,  PA (US);  Caren Ann Puschak,  Norristown, PA (US);  Cindy Eckert,  Collegeville, PA (US);  Ralph Craig  Even,  Blue Bell, PA (US)  (73)  Assignee:  Rohm and Haas Company,  Philadelphia, PA (US)  ( *)  Notice:  Subject to any disclaimer, the term of this  patent is extended or adjusted under 35  U.S.C. 154(b) by  O  days.  (21)  Appl. No.:  10/410,068  (22)  Filed:  Apr. 9, 2003  (65)  Prior Publication Data  US 2004/0010071 Al Jan. 15, 2004  Related U.S. Application Data  (60)  Provisional application No. 60/417,855, filed on Oct. 11,  2002, and provisional application No. 60/371,192, filed on  Apr. 9, 2002.  (51)  Int. Cl.7  ...........................  COSL 33/04;  C08L 33/02  (52)  U.S. Cl.  .......................  524/515;  524/502; 524/556;  524/560; 526/224; 526/229  (58)  Field of Search  ................................. 524/502, 556,  524/560, 515; 526/224, 229  (56)  References Cited  U.S. PATENT DOCUMENTS  5,308,890 A  5,344,675 A  5,567,773 A  5/1994 Snyder ....................... 523/201  9/1994 Snyder .................... 427 /388.4  10/1996 McGee et al. .............. 525/221  3/1998  5/1998  5,731,377 A  *  5,753,742 A  5,990,228 A  6,403,703 Bl  6,451,899 Bl  *  6,524,656 B2  6,545,084 B2  2003/0055171 Al  *  *  11/1999  6/2002  9/2002  2/2003  4/2003  3/2003  Friel .......................... 524/522  Bumanlag ................... 524/501  Eichman et al. ............ 524/529  Slone ......................... 524/832  Zhao et al. ................. 524/501  Even et al. .............. 427/393.5  Brown et al. ............... 524/556  Overbeek et al. ........... 525/192  OTHER PUBLICATIONS  CopendingApplication 10/162,456; filing date: Jun. 4, 2002.  Copending Application 10/162,457; filing date Jun. 4, 2002.  Copending Application 09/981,350, filing date Oct, 17,  2001.  U.S. Appl. No. 10/162,456, filed Jun. 4, 2002.  U.S. Appl. No. 10/162,457, filed Jun. 4, 2002.  U.S. Appl. No. 09/981,350, filed Oct. 17, 2001.  *  cited by examiner  Primary Examiner-David  W. Wu  (74)  Attorney, Agent, or Firm-Kim  R. Jessum; Gary D.  Greenblatt  Assistant Examiner----Satya  Sastri  (57)  ABSTRACT  10 Claims, No Drawings  An aqueous polymer blend composition including a pre› dominant amount of soft polymer particles and a minor  amount of hard polymer particles is provided. The soft  polymer particles contain, as copolymerized units, 70 to  99.7% by weight monoethylenically unsaturated (meth)  acrylic monomer and from 0.3 to 10% by weight monoet› hylenically unsaturated acid monomer, based on weight of  soft polymer particles. The soft polymer particles are made  by a select process including redox polymerization or poly› merization in the presence of excess unreacted monomer.  The aqueous polymer blend composition is useful for pre› paring dry coatings having improved dirt pickup resistance  and acceptable scrub resistance. A method is provided for  preparing a dry coating from the aqueous polymer blend  composition.  US006930141B2 