Test for Desorption of Agents HD and GD from Chemical Agent Resistant Coating(CARC)

摘要

A method of measuring the desorbed residual agent from chemical agent resistantcoating (CARC) paint, after exposure and rinsing, is thoroughly examined in a round-robin test. The test showed that some CARC formulations met the agent-resistance specifications desorbed excess agent, but other formulations met the agent-resistance specification. There is evidence showing that those paints that do not meet specification for agent resistance do so because of excess porosity (in the mesopore range) due to the paint, as applied, being above the critical pigment volume concentration (CPVC). That is, the ratio of pigment-to-liquid component is greater than that proportion at which the liquid component, after complete polymerization and evaporation of all residual solvent, is not sufficient to fill all the voids between the pigment particles. CARC must be formulated near the CPVC to have the necessary surface roughness to meet the specification for low sheen and spectral reflectance required in the camouflage colors. Limitations of the round-robin test are presented with suggestions for an improved test. A statistical determination of acceptability, using thetest in a two-stage experimental determination of the amount of agent desorbed to accept or reject prospective lots of CARC, is presented. Keywords: Chemical agent, Polyurethane, Camouflage, Round-robin test, Agent resistance. (SDW)