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Paint&pintura | Novembro 2013 | 9
have technologies that are silicone-free and based on specialty emulsions,
polysiloxanes and star polymers,” says Marlon Braidott, technical service
consultant to BASF.
By concept and definition, defoamers are products that avail themselves
of a certain degree of “incompatibility” with the coating system in order
to destabilize the incorporated air (foam), be it in the course of the mixing
and preparation or application process, be it by increasing porosity/air
permeability on the substrate, be it through chemical reactions occurring
in the coating film. “However, as a result of that same incompatibility with
the system, the right choice of defoamer chemistry and type is critical to
correcting the formulationwithoutmaking any compromise on performan-
ce. It is also worth pointing out that attention is needed to the detail that
different systemswill requiredifferent defoamers for abalancedaction level
and degree of incompatibility/interference,” explains Paulo Roberto Vieira
Junior, PhD, technical coordinator at Allnex’s Coatings Resins andAdditives
business for South America.
Defoamer chemistries available include modified or unmodified silicones,
mineral oils, fatty acid derivatives and even specialty polymers. “There’s
an emerging trend in the marketplace towards multi-compatible products,
meaning defoamers that can be effectively applied to various paint and
coating systems, featuring easier formulation and incorporation, as well as
the least possible interference with the end performance,” Vieira remarks.
OxygenatedSolvents -Growth inSynergywithSustainability
Present in various coatings which, as a result, cover various markets, oxy-
genated solvents are well on the way to sustainability.
Before specifically addressing the main theme for this piece, which is
oxygenated solvents, I would like to propose a reflection upon the paint
and coatings market and its potential waves of growth. Statistics from the
Brazilian Association of Paint Manufacturers, known for short as Abrafati,
show that Brazil is one of theworld’s top-fivemarkets. Here, paints arema-
nufactured for themost variedof applications,withcutting-edge technology
and a degree of technical skill comparable to that of the most advanced
manufacturing facilities on the planet.
Used in virtually all types of formulations, especially automotive OEM
and refinish coatings, home appliance finishes and road-marking paints,
oxygenated solvents ensure optimal solubility, while improving physical
properties related to gloss, sagging, drying, tack, lower VOCs and reduced
toxicological potential.
Rodrigo Gabriel, product development director at Carbono, maintains that
the consumption of oxygenated solvents has increased due to environ-
mental requirements, while stressing that a clear definition is needed as to
what an environmentally compliant products is. “Might it be a low-toxicity
product? A biodegradable one? One not harmful to human health when
handled? One produced with materials from
100-percent renewable sources? Well, if this is
the case, then there virtually is nooxygenated
solvent that fits in the definition. Just because
a product contains an oxygen molecule in its
structure doesn’t mean it is to be considered
to have no consequences to the environment
or to humans. Studies recently conducted
in the adhesive market compared certain
oxygenated solvents to aromatic ones, and
the resulting toxicity to humans was similar.
Aromatic solvents have been demonstrated
to perform better than oxygenated solvents
in the most varied of applications. Price levels
for products from the two of these lines have
changed significantly. Lower prices for certain
oxygenated solvents have in fact been the
main driver of the technology shift, and not
the environmental trend,” he tells.