GELLED COMPOSITIONS FOR REMOVING COATINGS FROM COATED SURFACES
ABSTRACT
Organic coatings may be
removed from their substrates by treating the coated substrate with a gelled
organic solvent. For example, paint may be stripped from metal, wood,
etc. by the process of contacting the paint with a gelled composition formed
from turpentine or other organic solvent in combination with a suitable gellant
for the solvent, e.g., a polyamide resin. The coating dissolves into the
gel and/or the solvent from the gel is able to diffuse between the coating and
the underlying substrate, thereby dissolving and/or loosening the coating so
that the process of removing the gel also removes some or all of the
coating. Multiple applications of gelled organic solvent may be needed to
completely remove the coating. A gel is particularly advantageous when
the coated surface is vertically positioned because the gel will resist running
down the coated surface, and accordingly the gel will retain contact with the
surface for as long as desired.
A.
Background
Chemical paint strippers are typically either gels or
low-viscosity solvents.
Low-viscosity solvents are deficient for several reasons. For instance, they are often volatile,
which means that their use can cause environmental damage as well as cause
inconvenience to the person who is applying the solvent. In addition, when low-viscosity
solvents are applied to a vertical surface, the solvent runs down the surface. It is difficult to keep enough of the
low-viscosity solvent at the upper regions of a vertical surface to achieve the
desired goal. Also, as the
low-viscosity solvent runs down a vertical surface, it may and typically does
dissolve some of the paint, thereby causing paint/solvent to soak into the
ground, unless precautions are taken to capture the run-off.
As for gels, the currently available gels are typically stringy
and heterogeneous. This
consistency makes them very difficult to apply to a surface. The person applying the gel finds that
the gel adheres, in part, to the surface and in part to the brush used to apply
the gel. As the brush applies the
gel, the gel tends to pull away from the surface back onto the brush. To reduce this problem, the person
applying the gel may try to use a lot of gel, so that an unnecessarily thick
coating is placed on the surface.
As environmental concerns increase, there is a need to utilize
chemistries that can be safely and easily coated to vertical and exposed
surfaces. The present invention
provides a shear thinnable gel that can be easily applied to and then removed
from a coated surface.
B.
Gels
The gelled paint/coating removers as disclosed herein contain
gellant, solvent that is gelled by the gellant, and optional ingredients. The gel is preferably not stringy and
is easily applied to a coated surface.
Suitable gellants, solvents and optional ingredients, as well as methods
to manufacture the gels, are described below.
1.
Gellants and solvents
The following are ex...