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