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Proposed Performance Criteria for Encapsulant Coatings for Lead Paint. Part 1. Abrasion Resistance.


pdf icon Proposed Performance Criteria for Encapsulant Coatings for Lead Paint. Part 1. Abrasion Resistance. (3095 K)
Rossiter, W. J., Jr.; McKnight, M. E.; Roberts, W. E.; Kraft, K. M.

NISTIR 5901; 39 p. December 1996.

Sponsor:

Department of Housing and Urban Development, Washington, DC

Available from:

National Technical Information Service
Order number: PB97-138267

Keywords:

paints; coatings; abrasion resistance; building technology; curing; dynamic mechanical analysis; encapsulants; glass transition temperature; lead based paints; performance criteria

Abstract:

This study was conducted to develop preliminary performance criteria for encapsulants for lead based paint. ASTM standards have been developed for encapsulants and data in the study may support revisions to these standards. Encapsulants are liquid-coating-based products installed over the surface of the laed-based paint to help to minimize the hazards of lead-based paint in housing. This report, the first in a series on the performance criteria, describes the cure time and abrasion resistance of 10 commercial encapsulants. Six nonrefinforced and four reinforced encapsulants were selected. Six were acrylic-resin based; others were epoxyy-, polyester-, and polyurethane-resin based, and one was inorganic-cement based with an acrylic binder. Two household paints were included as controls. Before conducting the abrasion tests, it was necessary to characterize the cure of the samples; that is, the change of the liquid-applied coating from a wet film to a solid film. Characterization of the cure was accomplished by following the glass transition temperature over time using dynamic mechanical analysis (DMA). The results indicated that seven encapsulants and the two paint samples showed little or no change in glass transition temperatures within four weeks or less fter application, i.e., they were essentially fully cured. In contrast, three encapsulants displayed glass transition temperatures which were still increasing after at least 13 weeks, although the dry films exhibited no indications that they should not be tested after four weeks.