Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Reexamination Certificate
2000-04-20
2003-12-09
Reddick, Judy M. (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
C524S238000, C524S243000, C524S245000, C524S543000, C524S558000, C524S560000, C524S563000
Reexamination Certificate
active
06660801
ABSTRACT:
This invention relates to an aqueous coating composition having improved adhesion to friable surfaces such as chalky weathered paint surfaces and masonry surfaces. More particularly, this invention relates to an aqueous coating composition including an emulsion polymer of selected composition having a glass transition temperature (Tg) of −20 C to 100 C and an average particle diameter less than 120 nanometers, and 0.25-10 wt. % of a water-soluble alkoxylated amine. And the invention relates to a method for improving the adhesion of a dried aqueous coating composition to a friable surface by forming an aqueous coating composition including an emulsion polymer of selected composition having a glass transition temperature (Tg) of −20 C to 100 C and an average particle diameter less than 120 nanometers, and 0.25-10% of a water-soluble alkoxylated amine; applying the aqueous coating composition to a friable surface; and drying, or allowing to dry, the aqueous coating composition.
The present invention serves to provide a dried coating which has improved adhesion to a friable surface. Coatings are frequently desirably applied to surfaces which are both porous and weak, i.e., subject to attrition on abrasion such as, for example, chalky surfaces of coatings which have weathered to an extent that poorly consolidated pigment forms a surface layer on the coating and masonry surfaces, weathered or not, which have a poorly consolidated surface. A substrate to which a coating is applied may have an entirely friable surface or only portions of the surface may be friable. Such substrates present a problem to the applicator in that, without being bound by this mechanism, the aqueous coating composition may not penetrate the weak boundary layer of the friable surface or friable surface areas sufficiently to provide a dry coating with the requisite degree of adhesion to the substrate below the weak surface.
U.S. Pat. No. 4,771,100 discloses the use of ethoxylated fatty amines in the preparation of latexes containing about 0.1 to 10 weight percent of copolymerized carboxylic acid monomer which have particle sizes between 889 and 1091 Angstroms for use as coatings. Improved adhesion to friable surfaces is desired.
Adhesion to a substrate to which it has been applied is a generally desirable characteristic of a coating. However, some surfaces are notoriously difficult to adhere to and coatings which adhere well to sound surfaces will fail to adhere to such surfaces. One such difficult surface is a friable surface, that is, one on which a weak, poorly bound, inadequately consolidated surface layer such as a badly chalking weathered paint surface or a brittle, crumbling masonry surface, is to be coated. The problem faced by the inventors is the provision of a suitable aqueous coating composition and a method for improving the adhesion of a coating so that that adhesion to friable surfaces can be effected. We have now found that that certain polymer compositions used in conjunction with water-soluble alkoxylated amines provide improved adhesion to friable surfaces relative to alternative compositions.
In a first aspect of the present invention there is provided an aqueous coating composition having improved adhesion to friable surfaces including an emulsion polymer having a glass transition temperature of −20 C to 100 C and an average particle diameter less than 120 nanometers, the emulsion polymer having at least one copolymerized ethylenically unsaturated nonionic monomer, each of the nonionic monomer(s) having a water solubility less than 8%, and at least one copolymerized acid monomer, such that the acid number of the emulsion polymer is 30 to 100; and 0.25-10%, by weight based on the emulsion polymer weight, water-soluble alkoxylated amine.
In a second aspect of the present invention there is provided an aqueous coating composition having improved adhesion to friable surfaces including an emulsion polymer having a glass transition temperature of −20 C to 100 C and an average particle diameter less than 120 nanometers, the emulsion polymer having 8-99.5%, by weight based on the weight of the emulsion polymer, of at least one copolymerized ethylenically unsaturated first nonionic monomer, each of the first nonionic monomer(s) having a water solubility of 8% or more, 0-91.5%, by weight based on the weight of the emulsion polymer, of at least one copolymerized ethylenically unsaturated second nonionic monomer, each of the second nonionic monomer(s) having a water solubility of less than 8%, and at least one copolymerized acid monomer, such that the acid number of the emulsion polymer is 4 to 100; and 0.25-10%, by weight based on the emulsion polymer weight, water-soluble alkoxylated amine.
In a third aspect of the present invention there is provided a method for improving the adhesion of a dried aqueous coating composition to a friable surface including forming an aqueous coating composition including an emulsion polymer having a glass transition temperature of −20 C to 100 C and an average particle diameter less than 120 nanometers, the emulsion polymer having at least one copolymerized ethylenically unsaturated nonionic monomer, each of said nonionic monomer(s) having a water solubility less than 8%, and at least one copolymerized acid monomer, such that the acid number of the emulsion polymer is 30 to 100, and 0.25-10%, by weight based on polymer weight, water-soluble alkoxylated amine; applying the aqueous coating composition to a surface; and drying, or allowing to dry, the aqueous coating composition.
In a fourth aspect of the present invention there is provided a method for improving the adhesion of a dried aqueous coating composition to a friable surface by forming an aqueous coating composition including an emulsion polymer having a glass transition temperature of −20 C to 100 C and an average particle diameter less than 120 nanometers, the emulsion polymer having 8-99.5%, by weight based on the weight of the emulsion polymer, of at least one copolymerized ethylenically unsaturated first nonionic monomer, each of the first nonionic monomer(s) having a water solubility of 8% or more, 0-91.5%, by weight based on the weight of the emulsion polymer, of at least one copolymerized ethylenically unsaturated second nonionic monomer, each of the second nonionic monomer(s) having a water solubility of less than 8%, and at least one copolymerized acid monomer, such that the acid number of the emulsion polymer is 4 to 100, and 0.25-10%, by weight based on polymer weight, water-soluble alkoxylated amine; applying the aqueous coating composition to a surface; and drying, or allowing to dry, the aqueous coating composition
The aqueous coating composition contains a waterborne emulsion polymer. The emulsion polymer contains at least one copolymerized nonionic ethylenically-unsaturated monomer, such as, for example, a (meth)acrylic ester monomer including methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, decyl acrylate, methyl methacrylate, butyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, aminoalkyl (meth)acrylate; styrene or substituted styrenes; butadiene; vinyl acetate or other vinyl esters; vinyl monomers such as vinyl chloride, vinylidene chloride, N-vinyl pyrollidone; (meth)acrylonitrile and (meth)acrylamide. The use of the term “(meth)” followed by another term such as acrylate or acrylamide, as used throughout the disclosure, refers to both acrylates and acrylamides and methacrylates and methacrylamides, respectively.
The water solubility of the nonionic monomers incorporated into the emulsion polymers herein are defined as those determined using the Quantitative Structural Activity Relationship (QSAR) program. The program uses the molecular structure to estimate physical-chemical properties including, molecular weight, vapor pressure, solubility, bioconcentration factor, hydrolysis half-life, Henry's coefficient, partitioning data, and other parameters( based on Lyman, W., Reehl, W., and Rosenblatt, D. Handboo
Gebhard Matthew Stewart
Hageman Bradley Keith
Bakule Ronald D.
Reddick Judy M.
Rohm and Haas Company
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