Back to results
US 4,362,770 AGranted
Nitrocellulose-free primer-surfacer
AssigneeThe Sherwin-Williams Company
InventorsJohn Mathai, Larry J. Morrison
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
AssigneeThe Sherwin-Williams Company
InventorsJohn Mathai, Larry J. Morrison
Estimating the term…
Disclosed is a primer-surfacer composition comprising a vehicle of a balanced acrylic polymer of methyl methacrylate, butyl methacrylate and methacrylic acid, the resultant polymer having an acid value in the range of about 25 to 35, the polymer having a relative viscosity of about 16 to 32 poise measured at 40% polymer solids in a toluene and isopropyl alcohol solvent at 25.degree. C. The primer-surfacer may also contain dispersed pigments and/or fillers such as carbon blacks, talc, iron oxide, clay, etc. The primer-surfacer composition is primarily used over unprimed, primed or previously finished metal or plastic substrates to provide a surface to which an acrylic lacquer, an acrylic enamel, an alkyd enamel or a polyurethane enamel coating can be applied. The primer-surfacer of this invention may be easily sanded to provide a finish for vehicles of excellent intercoat adhesion, excellent chip and corrosion resistance and excellent fill.
In a coated substrate wherein the substrate is selected from a group consisting of ferrous and non-ferrous metals and plastics, and the coating comprises a preliminary primer-surfacer coat and a finish coat selected from a group consisting of acrylic lacquer, enamel and urethane coating applied over said primer, the improvement which comprises said primer-surfacer comprising 35-67 percent by weight inert solvent and 65-33 percent by weight of an acrylic polymer vehicle having an acid value of 25-35 and a viscosity ranging from 16-50 poise at about 40% polymer solids as measured in a toluene/isopropanol, 95%/5%, solvent at 25.degree. C., said acrylic polymer vehicle consisting essentially of the polymerization reaction product of methyl methacrylate, butyl methacrylate and methacrylic acid with a free radical initiator.
A nitrocellulose-free primer-surfacer composition comprising 35-67% by weight inert solvent and 65-33% by weight of an acrylic polymer vehicle, said acrylic polymer vehicle being a copolymer of methyl methacrylate, butyl methacrylate and methacrylic acid having a molecular weight ranging from 75,000 to 150,000, an acid value of about 25-35 and a viscosity measured at 40% polymer solids in a 95% toluene/5% isopropanol solvent at 25.degree. C. of 16-50 poise.
Dependencies are inferred from the claim text.