Aqueous polymer dispersions
AssigneeRohm and Haas Company
InventorsDavid Fasano, Matthew Gebhard, Kathleen Koziski, Willie Lau, Aurelia Sheppard
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Abstract
An aqueous polymer dispersion comprising polymer particles (A), polymer particles (B) and at least one low molecular weight polymer (C) where polymer particles (A) comprise high molecular weight polymer pA having Mw >50,000 and acid number of from 0 to 160, polymer particles (B) comprise high molecular weight polymer pB having Mw >50,000 and acid number of from 0 to 160, and C is an addition polymer having a calculated Tg,(low) of less than 10° C., Mn <10,000, acid number of from 0 to 80, formed by the polymerization of at least one ethylenically unsaturated nonionic monomer
Claims10
An aqueous polymer dispersion comprising polymer particles (A), polymer particles (B) and at least one low molecular weight polymer (C) where,
- a) polymer particles (A) comprise high molecular weight polymer pA having Mw >50,000 and acid number of from 0 to 160,
- b) polymer particles (B) comprise high molecular weight polymer pB having Mw >50,000 and acid number of from 0 to 160,
- c) C is an addition polymer having a calculated Tg,(low) of less than 10° C., Mn <10,000, acid number of from 0 to 80, formed by the polymerization of at least one ethylenically unsaturated nonionic monomer, wherein
- d) the weight percentage of pA, based on the total weight of polymer in said dispersion, is at least 5%,
- e) the weight percentage of (C) is at least 5%, based on the total weight of pA,
- f) pA is formed in the presence of (C) or (C) is formed in the presence of pA, and
- g) polymer particles (A) differ from polymer particles (B) in at least one of;
- particle size, Tg, acid number, composition, molecular weight, molecular weight distribution, polymer chain structure.
An aqueous polymer dispersion as in any of the preceding claims wherein the Mn of C is <7,500.
An aqueous polymer dispersion as in any of the preceding claims wherein the Mn of C is <4,000.
An aqueous polymer dispersion as in any of the previous claims wherein the calculated Tg∞ of pA differs from the calculated Tg∞ of pB by at least 10° C.
An aqueous polymer dispersion as in any of the previous claims wherein the number average particle size of polymer particles (A) differs from that of polymer particles (B) by at least 50 nanometers.
An aqueous polymer dispersion as in any of the previous claims wherein (C) is formed in the presence of a macromolecular organic compound having a hydrophobic cavity.
An aqueous polymer dispersion comprising polymer particles (A), polymer particles (B) and at least one low molecular weight polymer (C) wherein,
- a) polymer particles (A) comprise high molecular weight polymer pA having Mw >50,000, acid number of from 0 to 160, and calculated Tg∞ of at least 40° C.,
- b) polymer particles (B) comprise high molecular weight polymer pB having Mw >50,000, acid number of from 0 to 160 and calculated Tg∞ of −10 to 30° C.,
- c) C is an addition polymer having a calculated Tg,(low) of less than 10° C., Mn <10,000, acid number of from 0 to 80, formed by the polymerization of at least one ethylenically unsaturated nonionic monomer, wherein
- d) the weight percentage of pA, based on the total weight of polymer in said dispersion, is at least 5%,
- e) the weight percentage of (C), based on the total weight of polymer in the dispersion, is at least 1%.
A coating composition comprising an aqueous dispersion according to any of the preceding claims.
Dependencies are inferred from the claim text.