GMA Acrylic Powder Resins are made by free
radical, solution copolymerization of Glycidyl methacrylate (GMA) with
other acrylic or vinyl aromatic co-monomers.
The stable -C-C- polymer backbone of GMA resins confers good outdoor weathering & chemical resistance.
Unlike liquid coatings, GMA acrylics used in
powder coating are restricted as to monomer selection due to the
requirement that resins be non sintering solids. Hence, the glass
transi- tion temperature (Tg) of the final resin is designed to be
above some minimum value (usually 40-45 deg. C) to insure physical
stability of the powder coating. Tg of GMA acrylic powder resin is
controlled by two equations:
Removal of solvent &
unreacted monomers used in the manufacturing process is important to
maintaining the essentially zero VOC advantage of powder coatings. The
volatile contents of Almatex resins are well controlled to below 0.1%.
By controlling monomer compositions and
molecular weight, Almatex GMA resins can be designed with a very wide
range of melt viscosities, Tg, epoxy equivalent weight, and
functionality for different application needs. The selection of
specialty monomers and certain polymer modification processes can give
Almatex GMA powder resins with properties such as enhanced
pigmentation, compatibility and flexibility.
ADC and its parent company Mitsui Chemicals
Inc have full capability to tailor-make Almatex GMA acrylic powder
resins to fit various special application needs.
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