Low VOC Barrier Coating for Industrial Maintenance
Abstract
The objectives of this demonstration are to (1) provide a full-scale validation of the low volatile organic compound (VOC) barrier coating (LVBC) for use as an architectural and industrial maintenance (AIM) coating, (2) assist in the transition of a nonaircraft topcoating using the zero- VOC topcoat (ZVT) (MIL-PRF-85285D, Type III, Class W), and (3) enable the transition of this very low VOC AIM coating system directly into the hands of U.S. Department of Defense (DoD) end users who require aboveground storage tank (AST) maintenance painting. Corrosion of AST steel exterior surfaces is a perennial and costly problem. To protect against corrosion, AST exterior surfaces typically receive a three-coat system consisting of the following: 1) A zinc-rich epoxy primer (Military Detail Standard [MIL-DTL]-24441, Formula 159, Type III); 2) An epoxy intermediate (MIL-DTL-24441, Formula 152, Type IV); and 3) A polyurethane topcoat (Military Performance Standard [MIL-PRF]-85285D, Type II). These coats are commonly formulated with about 304 grams per liter (g/l) (2.5 pounds per gallon [lbs/gal]), 340 g/l (2.8 lbs/gal) and 340 g/l (2.8 lbs/gal) of VOCs, respectively. Exterior AST maintenance painting is often required at around 8 to 10 years of service. However, the original three-coat system described above is not appropriate for use over aged and weathered coatings. When the original system has been used as an overcoat system, it has contributed to costly premature coating failures. These overcoat failures typically occur as a result of high levels of residual cure stress (curing of the overcoat system) combined with the daily thermal cycling (daily temperature extremes). Therefore, typical maintenance consists of making spot repairs to visibly corroded areas or waiting until the existing coating is fully removed and a reapplication is necessary.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 2012
- Accession Number
- ADA600418
Entities
People
- Daniel A. Zarate
- Michael Zapata
- Susan A. Drozdz
Organizations
- Environmental Security Technology Certification Program