MIL-PRF-32440, PERFORMANCE SPECIFICATION: COATINGS, CHIP-RESISTANT (28-FEB-2013)
MIL-PRF-32440, PERFORMANCE SPECIFICATION: COATINGS, CHIP-RESISTANT (28-FEB-2013)., This specification covers chip-resistant coatings for use on areas of military vehicles or ground support equipment which may encounter wear and abrasion. Examples of subject areas are bed liners and cargo beds of trucks, undercarriages of ground support equipment, and other areas subject to abrasion and wear, which may abrade original equipment manufacturer (OEM) and traditional coatings.
The chip-resistant coating covered by this specification is intended for use on areas of military vehicles or ground support equipment which may encounter wear and abrasion. The coating is a 100 percent solids, two-component chemical cure lining used in protecting profiled, cleaned, and primed (when required) wood, concrete, rigid plastic, fiberglass, elastomeric plastic, and metal substrates. The coating and lining system is intended for protection against abrasion, stone and gravel impact, mild chemicals, corrosion, vibration, and sound emission over a wide temperature range. This material is designed for use as a durable spray-on protective layer for thermal insulation and abrasion resistance on vehicle interior surfaces such as doors and floors, and abrasion-prone vehicle exterior surfaces such as wheel wells, undercarriages, footsteps, equipment storage areas and beds for tactical, combat, and construction equipment. A durable trowel-on repair compound is also covered in this specification.
This coating can be made from a wide variety of chemistries, such as polyurethane, polyurea, and a combination of polyurea and polyurethane (hybrid coating). Regardless of chemistry, the coating cannot contain any hazardous TDI or any free monomers of MDI or its most common isomers 2,2\', 2,4\', and 4,4\' MDI or HDI. The coating can be aromatic or aliphatic in nature.
The material can be applied with a variety of application equipment ranging from high volume production plural component equipment to moderate volume static mix cartridge guns and small volume spot repair kits. The approximate film thickness is dependent on the particular application needs. A general guideline is to use approximately 50 mils (0.050 inch) of coating thickness in high use or chip prone areas like wheel wells, undercarriages, and other similar areas and lower film thicknesses (approximately 20 mils) in less demanding application areas like vehicle interiors. The material can easily be repaired with small volume repair kits and readily bonds with itself.