Aqueous dispersion of polymeric particles

• US 20050203211A1
• Filed: 03/07/2005
• Published: 09/15/2005
• Est. Priority Date: 03/09/2004
• Status: Abandoned Application

• Current Assignee: Matthew Stewart Gebhard
• Original Assignee: Matthew Stewart Gebhard
• Inventors: Gebhard, Matthew Stewart
• Application Number:
  US11/073,767
• Publication Number:
  US 20050203211A1
• Time in Patent Office: Days
• US Class Current: 523/205
• CPC Class Codes: C08F 2/22 Emulsion polymerisation
• CPC Class Codes: C08F 265/06 Polymerisation of acrylate or methacrylate esters on to polymers thereof
• CPC Class Codes: C09D 151/003 grafted on to macromolecular compounds obtained by reactions only involving unsaturated carbon-to-carbon bonds C09D151/04, C09D151/06 take precedence

Abstract

A selected aqueous dispersion of polymeric particles, preferably formed by a two-stage emulsion polymerization process, the particles including: from 5% to 20% by weight, based on the weight of the polymeric particles, of a first polymer including at least one copolymerized ethylenically unsaturated nonionic monomer, the first polymer having a glass transition temperature (Tg) of from 40° C. to 95° C.; and from 80% to 95% by weight, based on the weight of the polymeric particles, of a second polymer including at least one copolymerized ethylenically unsaturated nonionic monomer and from 0.25% to 5% by weight, based on the weight of the second polymer, of a copolymerized aldehyde-reactive monomer, the second polymer having a Tg of from −20° C. to 0° C. and an acid number of from 2 to 160, is provided. Also provided is an aqueous coating composition including the dispersion of polymeric particles, a method for providing a coated substrate including applying the aqueous coating composition to a substrate, and a coated substrate formed by the method.

Claims

1. An aqueous dispersion of polymeric particles, said particles comprising:

from 5% to 20% by weight, based on the weight of said polymeric particles, of a first polymer comprising at least one copolymerized ethylenically unsaturated nonionic monomer, said first polymer having a glass transition temperature (Tg) of from 40°

C. to 95°

C.; and

from 80% to 95% by weight, based on the weight of said polymeric particles, of a second polymer comprising at least one copolymerized ethylenically unsaturated nonionic monomer and from 0.25% to 5% by weight, based on the weight of said second polymer, of a copolymerized aldehyde-reactive monomer, said second polymer having a Tg of from −

20°

C. to 0°

C. and an acid number of from 2 to 160.

2. The aqueous dispersion of claim 1 wherein at least one of said first polymer and said second polymer comprises from 0.25% to 20%, by weight, based on the weight of said polymer, of a copolymerized alkyl-substituted vinyl aromatic monomer.

3. The aqueous dispersion of claim 1 formed by an emulsion polymerization process wherein said second polymer is formed in the presence of said first polymer.

4. The aqueous dispersion of claim 3 wherein said first polymer further comprises from 0.1% to 5% by weight, based on the weight of said first polymer, of a copolymerized multiethylenically unsaturated monomer.

5. The aqueous dispersion of claim 3 wherein said particles comprise from 5% to 15% by weight, based on the weight of said polymeric particles, of said first polymer further comprising from 0.25% to 3% by weight, based on the weight of said first polymer, of a copolymerized multiethylenically unsaturated monomer, said first polymer having an acid number of from 0.1 to 13;

and

from 85% to 95% by weight, based on the weight of said polymeric particles, of said second polymer having a Tg of from −

13°

C. to −

6°

C. and an acid number of from 2 to 30.

6. An aqueous coating composition comprising the aqueous dispersion of claim 1 and at least one pigment, said coating composition having a pigment volume concentration (PVC) of from 5 to 60 and having a volatile organic content (VOC) of less than 5%.

7. The aqueous coating composition of claim 6 further comprising from 0.1 to 1 weight % benzophenone, based on dry polymer weight.

8. A method for providing a coated substrate comprising:

forming the aqueous coating composition of claim 6;

applying said aqueous coating composition to said substrate; and

drying, or allowing to dry, said aqueous composition.

9. A coated substrate formed by the method of claim 7.