GLOSSARY
A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z
U
UNDERCOAT
Any coat applied after the primer and
prior to the finish coat. An undercoat normally is used on wood trim
and some metals where exceptional smoothness is desired.
UNDERCUTTING
The penetration of a coating and the
spread of delamination or corrosion from a break or pinhole in the film
or from unprotected edges.
UNDERFILM CORROSION
Corrosion that occurs between a coating
and the metal substrate without a break in the coating layer.
UEL - UPPER EXPLOSIVE LIMIT
The concentration at ordinary ambient
temperatures of a compound in air above which an explosion will not
occur if the mixture is ignited. UEL is expressed in percent of the
gas vapour in air by volume.
URETHANE ALKYD (URALKYD) RESIN
Alkyd resin systems modified with isocyanate.
These modifications can decrease the drying time and enhance resistance
to chemicals, moisture, weathering, and abrasion of the alkyd resins.
URETHANE COATING
A coating whose vehicle contains a poly-isocyanate
monomer reacted with various other materials. Urethane coatings can
be obtained as air-drying, moisture-cured, or catalysed types.
