Method of applying traffic marking onto an oily road surface and traffic paints formulated therefor

#This invention relates to a method of producing traffic markings which readily adheres to various substrates associated with roads and highways. More particularly, the method of the present invention is useful as a traffic paint which readily adheres to roadbeds that have an oily surface.

#White and yellow traffic markings used for demarcating traffic lanes are a common sight on almost all roads. These markings provide the necessary guidance to ensure safe driving conditions under varying weather conditions. Within the context of traffic markings, the term “roads” is more expansive than merely streets and highways. “Roads” is used herein as a generic term and it includes any indoor or outdoor solid surface that is or may be exposed to pedestrians, moving vehicles, tractors or aircraft, either continuously, continually or intermittently. Some examples or “roads” include highways, streets, driveways, sidewalks, runways, taxiing areas, tarmac, parking lots and indoor floors (such as factory floors or floors inside shopping malls). The surface materials of “roads” may be masonry, asphalt, resins, concrete, cement, stone, stucco, tiles, wood, polymeric materials and any combinations thereof. Also, as used herein, “roads” embraces any surface of any substrate associated with roads, including, for example, signs, barricades, medial strips and traffic signal devices.

#The majority of traffic markings, such as solid, transverse or interrupted stripes, are paint-based and traditionally include solvent-borne binders, these being predominantly alkyds and chlorinated rubber modified alkyds. However, since the early 1980's, environmentally safer paints based on water based solvent systems began to be employed. These waterborne traffic paints are primarily based on acrylic emulsions and produce dramatically lower volatile organic content (“VOC”) emissions than traditional solvent-based traffic paint systems.

#To 900 g of deionized (DI) water under a nitrogen atmosphere at 90° C. was added 6.3 g of ammonium bicarbonate dissolved in 50 g DI water, 7.8 g ammonium persulfate dissolved in 92 g DI water and 131 g polymer seed latex (solids content 42% average particle diameter of 60 nm) followed by 20 g of DI water to form a reaction mixture to which the following monomer mixture was then added over 3 hours at 85° C. along with a solution of 5.2 g ammonium persulfate dissolved in 50 g DI. 1 Monomer mixture: in grams (g) DI water 625 Surfactant * 33.5 butyl acrylate 1200.0 styrene 766.0 acrylic acid 34.0 n-dodecylmercaptan 20.0 * Ethoxylated C6-C18 alkyl ether sulfate having 1 to 40 EO groups per molecule (30% active in water)

#At the end of the polymerization, 0.01 g FeSO4 in 9 g DI water, 0.01 g Versene® 220 in 9 g of DI water, 4.0 g t-butylhydroperoxide in 30 g DI water and 2.0 g isoascorbic acid in 30 g DI water were added at 60° C. to the reaction product. Ammonium hydroxide was added to give a final pH=10. The resulting latex polymer had a solids content of 50.8% and an average particle diameter of 225 nm.

#To 750 g of deionized (DI) water under a nitrogen atmosphere at 90° C. was added 6.4 g sodium carbonate dissolved in 70 g DI water, 6.4 g ammonium persulfate dissolved in 70 g DI water and 150 g polymer seed latex (solids content 42% average particle diameter of 60 nm) followed by 40 g of DI water to form a reaction mixture to which the following monomer mixture was then added over 3 hours at 85° C. along with a solution of 4.2 g ammonium persulfate dissolved in 70 g DI. 2 Monomer mixture: in grams (g) DI water 750 Surfactant * 31.5 Versene ® 220 (1.5% active) 6.8 butyl acrylate 460 methylmethacrylate 814 methacrylic acid 26 2-ethylhexylacrylate 700 n-dodecylmercaptan 20.0 * Ethoxylated C6-C18 alkyl ether sulfate having 1 to 40 EO groups per molecule (30% active in water)