Many coating companies and coating resin manufacturers use evaluation methods to qualify performance of architectural primers for their ability to block interior household stains. However, while many of these methods are similar, there is currently no commonly accepted industry standard.
A proposed new ASTM standard being developed by ASTM International Committee D01 on Paint and Related Coatings, Materials and Applications would provide the coatings industry with an industry-wide method for evaluating the ability of an architectural paint system to block ink stains from typical markers and writing instruments from bleeding through primer or base-coat into a topcoat. The proposed standard, WK14688, Test Method for Ink Stainblocking of Architectural Paint Systems, is under the jurisdiction of Subcommittee D01.42 on Architectural Coatings.
Comparison of two primer coatings on an ink stainblocking test panel. The entire panel surface was topcoated with an interior latex paint that does not prevent ink stains from bleeding through. The inks are most visible on the right margin of the panel, which was topcoated but not primed.
According to Neal Rogers, chair of D01.42 and technical services representative, Cook Composites and Polymers, WK14688 will be used by chemists and paint formulators who evaluate architectural primer systems for companies in the coatings industry. Rogers says that coating manufacturers will be able to use WK14688 for performance evaluations of interior primers and for benchmarking against competitive products. Manufacturers of raw materials for coatings will find the proposed standard useful for the evaluation of coatings resins and additives on stainblocking performance.
In addition to manufacturers, architectural specifiers will be able to use WK14688 as a tool to ensure that primers will block stains as claimed. “For instance,” says Rogers, “the Florida School Plant Management Association maintains paint specifications that must be met in order for a coating to be recommended for application in public schools. One FSPMA specification, MP-38.1, requires a universal stainblocking primer to achieve a pass rating on an ink stainblocking test in order to be listed as a certified product.”
Subcommittee D01.42 invites interested parties to participate in its standards developing activities. Rogers says that the subcommittee would be particularly interested in people who have experience with a method that employs the application of ink stains so as to allow assessment using color measurement techniques. “Our current drafts of this method use a qualitative evaluation, such as a 1-10 rating scale, to rate how effective the coating is at blocking each stain,” says Rogers. “If practical, we wish to make the method more quantitative in nature by using spectrophotometer measurements to quantify the appearance effects of stains bleeding through the coating.” //
Technical Information: Neal Rogers, Cook Composites and Polymers, North Kansas City, Mo.
ASTM Staff: Timothy Brooke