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10
Outubro 2011
PAINT & PINTURA
mers are used in all kinds of pro-
cesses that involve the swirling
or stirring that causes the paint
to foam. In addition to their
anti-foaming action, defoamers
have a positive side effect on the
life of paints. When incorporated
into the paint system, defoamers
also prevent such undesirable
effects cratering and orange
peel, allowing the paint to be ap-
plied onto the substrate to form
uniform, well-leveled film, while
imparting great hiding power.
First and foremost, defoamers
must play their main role, which
is to prevent to the fullest extent
possible the formation and pre-
sence of bubbles and micro-bub-
bles in the both the production
and application of paints, ensuring the desired characte-
ristics of the end product. Due to their physicochemical
properties and their interaction with other components
of the formulation, their application needs controlling to
prevent side-effects.
Any insoluble substances in a paint formulation can
be used as defoamers, such as high molecular-weight
alcohols, mineral and plant oils or silicas, which are
excellent defoamers. For the most part, however, there
is a growing demand for defoamers that have no side-
-effects. High molecular-weight oils, silicas and organic
compounds will generate craters and fish eye defects and
impair the leveling of paints.
Therefore, there is an increasing demand among paint
manufacturers for solutions where a single defoamer
does the whole job. It used to be quite usual for three,
four or even five different anti-foaming additives to be
used together in paint formulations, and those products
would compete with each other in terms of effects. De-
foamers would destroy foam, but would cause cratering,
while surfactants would eliminate cratering, but cause
foam. For this reason, companies have been making mas-
sive investments in defoamers that are well-suited for a
wide variety of formulations.
Suppliers of defoamers to the paint industry have also
been seeking to associate their products with high per-
formance by developing multifunctional additives and
meeting health and environmental requirements, while
keeping costs under control, as required in any highly
competitive market.
Epoxy Resins - New generation
The paint market in general has become quite deman-
ding when it comes to selecting raw material, and that
includes epoxy resins, a segment where there has been
a considerable increase in the demand for waterborne
epoxy resins that can deliver just about the same perfor-
mance as solvent-borne systems. This is part of a major
trend in the industrial maintenance business towards
using more environmentally friendly products, which
also reflects in esterified epoxy resins, for industrial coa-
ting systems.
Epoxy resins are now required to be not only environ-