L
Lacquer
Coating based on a synthetic resin dissolved in organic solvent. Dries by
solvent evaporation. The film remains susceptible to attack by the same or
similar solvents.
Typical lacquers include those based on nitrocellulose, other cellulose derivatives,
vinyl resins, acrylic resins, etc.
Latex paint
Paint containing colloidal binder particles formed by emulsion polymerization.
A common term for water-based and water-reducible coatings.
Leafing
Ability of flat pigments to align themselves more or less parallel with the
coated surface. This property produces a reflective appearance of the film.
Leveling
agent
Additive which is able to reduce the surface
tension under dynamic and static conditions, to obtain an optimal wetting
and leveling effect, and to improve the surface flow of the coating. Poor
surface flow can induce coating defects such as orange-peel, craters, brush
marks... .
Lifting
Softening and raising or wrinkling of a previous coat by the application of
an additional coat; often caused by coatings containing strong solvents.
Light
degradation
Chemical decomposition and structural changes in polymers under the action
of UV light. Light degradation can cause coating defects such as internal
stress, loss of adhesion, cracking ... . Light degradation can be inhibited
by using UV / Light
absorbers.
Light
stabilizer
See UV / Light stabilizer
Liophilic
dispersion
Dispersion of surfactants and water-soluble polymers in water. Liophilic dispersions are
thermodynamically stable and reversible.
Liophobic
dispersion
Dispersion where the dispersed phase has a low
affinity toward the medium liquid. Polymer latexes and pigment suspensions
are typical liophobic dispersions.
Lubricant
Additive used to aid in the reduction of friction between two parts.
Luminescent
pigment
Special pigment available to produce striking effects in the dark. Basically there are two
types: one is activated by ultra-violet radiation, producing very strong luminescence and,
consequently, very eye-catching effects; the other type, known as phosphorescent pigments,
does not require any separate source of radiation.
