Message text written by "BP - His DNA is this long."
><< Proper terminology: solvent-borne or waterborne >>

Mike,

Thanks for the proper terminology... I've always been a bit confused about
this. Though I'm clear on your message, could you explain the distinctions
a
bit futher?

][<en<

The distictions revolve around active ingredients which accomplish the
sealer's performance objectives, 
as opposed to the volatile material used to deliver the active ingredients
in a form that is appropriate, such
as proper viscosity to permit some degree of penetration and to achieve the
appropriate coverage rates.

Some active ingredients are dissolved in petroleum-derived organic solvents
such as mineral spirits, xylene or others. These 
would be considered SOLVENT-BORNE. With the known nasty effects of most of
these solvents on air quality and ozone
layer integrity, the trend has been (ignoring what didn't happen during the
Reagan years) to replace as much of these
solvents as possible with water. Many active ingredients can be emulsified
(want to mix oil and water? just add soap), some
can be dissolved in water, and for sealers or coatings in which the primary
"solvent" is water, we apply the "WATERBORNE"
label. 

To further complicate matters, most waterborne sealers and coatings have
some level of other solvents present. For example,
a typical waterborne acrylic paint or sealer may have 2 to 5% solvents in
addition to something like 50 to 70% water. The solvents
help control the film-forming qualities, the drying times, and other
important properties. 

VOC is an acronym for volatile organic compounds. It is not a direct
measure of how much organic solvent is present, but higher
VOC content generally corresponds with higher solvent content. (The
calculation includes allowances for water and certain
Exempt solvents, such as acetone). The objective we formulators face is to
keep dropping VOC content, which in many areas
is regulated by law.

We can achieve zero or near zero VOC with certain materials, most notably
epoxy coatings based on 100% solids resins. In
100% solids coatings, there is no water and no solvent (or extremely
little). The material is a liquid because that is the natural
state of the resin at room temperature. A hardener is mixed with the liquid
resin just before application, causing a chemical reaction
which produces a much larger molecule which is naturally a solid. Although
the terminology is confusing (how can a liquid be a solid?),
it may be more straightforward to call these materials "100% non-volatile"
rather than 100% solids, since unlike the waterborne and
solvent-borne coatings, they do not rely on evaporation and film formation.

Mike E.