nestork wrote in
:


Red Green;3231975 Wrote:

100% acrylic latex to be more precise. Most flexability. Plastic
expands

& contracts A LOT.

Red Green:

About "100% Acrylic" paint.

Most people that throw that term around don't really know what it
means.

In North America, over 90 percent of the latex paint that's made is
made from one of two different kinds of plastics.

1. Polymethyl methacrylate - which you probably know better as
"Plexiglas" or "Lucite" or "Perspex", depending on which chemical
company made it. In the paint industry, latex paints and primers that
consist of gazillions of tiny hard spheres of this kind of plastic
suspended in a solution that is mostly water are referred to as "100%
Acrylic" paints, or paints with "100% Acrylic" resins.

2. Polyvinyl Acetate - which you probably know better as "PVA" or
white wood glue. In the paint industry, paints and primers that
consist of gazillions of tiny hard spheres of this kind of plastic
suspended in a solution that is mostly water are referred to as "Vinyl
Acrylic" paints, or paints with "Vinyl Acrylic" resins.

Note that there is no such thing as a "50% Acrylic" paint or a "75%
Acrylic" paint. It's either "100% Acrylic" or "Vinyl Acrylic" or
"Styrenated Acrylic".

The problem with this naming system is that people presume that if a
paint is 100% Acrylic, there's no point spending more on a higher
priced paint because you can never get higher than 100%, right?
Really, the wording "100% Acrylic" on a can of paint means about as
much as the wording "100% Cow" does on a package of meat. It tells
you the kind of plastic the paint is made of, but that's all. You
don't know if you're getting prime rib or dog food.

Generally, "100% Acrylic" latex paints are more expensive than "Vinyl
Acrylic" paints, and they:
a) have better resistance to acidic and alkaline substrates like fresh
concrete
b) have better UV resistance
c) dry to harder and marr resistant films,
d) stick better to damp or moist surfaces, and
e) don't exhibit any "blocking" which is when a paint remains slightly
sticky after it's fully dry.

Essentially ALL exterior latex paints will be made from polymethyl
methacrylate because of it's better UV resistance and the fact that
the film doesn't soften up and lose it's adhesion if it gets wet like
polyvinyl acetate paints and primers.

The problem with polyvinyl acetate paints and primers is that they
have lousy Alkaline resistance, lousy UV resistance and they lose
their hardness and start cracking and peeling if they get wet. Also,
they have poor "blocking" resistance in that an apparantly dry paint
film will still retain some residual stickiness.

If you ever look in someone's bathroom and see that the paint is
cracking and peeling above the shower, the problem is almost always
attributed to poor surface preparation prior to painting, but that's a
misdiagnosis of the problem. It's the fact that a cheap PVA paint was
used in the bathroom.

Also, if you've ever had doors and windows that tend to "stick" when
they're closed, the usual cause of that is a PVA paint being used on
them. When a door painted with a PVA paint closes and presses gently
againts a frame painted with PVA paint too, the two will stick to one
another causing problems. Again, the fix is to paint over the "vinyl
acrylic" paint with a "100% Acrylic" paint.

There are literally hundreds of different "100% Acrylic" resins used
to make primers, paints, floor finishes, nail polish for the ladies,
grout sealers and water based "varnishes". And, there are hundreds
more "vinyl acrylic" resins used to make mostly primers and budget
priced interior latex paints. So, specifying a "100% Acrylic" paint
is no more precise than specifying "cow" when you order a hamburger.





Sounds good. That should clear things up for the OP!