Note: Descriptions are shown in the official language in which they were submitted.
BACKGROUND OF THE INVENTION
The present invention relates to a composition
which in the form of a dried film is waterproof and elastic,
and has particular advantages as a coating for roofs and
walls.
Certain applications for waterproof coatings
have the most stringent properties required for the appli-
cations to be successful. These stringent property require-
ar~
ments~usually orders of magnitude greater than the property
requirements for more conventional coatings, such as
conventional house paints. The use of traditional mastic
compositions will generally result in an initially waterproof
coating. However, the conventional mastic coating has almost
no ability to absorb movement of the underlying surface,
either by crack development or by shifting of roof tiles or
the like, unless applied in relatively heavy thick coatings.
In this regard, most mastic coatings will be applied at a
total film thickness in the neiyhborhood of 30 or 40 mils
or even more. These coatings are quite difficult to apply
to roofs of cement tile or similar structures.
B~2
Because of the quite thick coatings which are
required for the successful use of conventional mastic coatings,
the economics of the coating system are not particularly
attractive, even though in some instances relatively cheap
starting materials are used. Mastic coatings generally lack
the desired degree of adhesion, and have little or no moisture
vapor transmission ability. Thus, moisture which may be
trapped underneath the coating, or which passes from under-
neath the roof to the coating-roof interface, is most likely to
cause blistering and adhesion failure of the mastic coating.
This can rapidly lead to failure of the entire coating.
Furthermore, the hiyh viscosity of the mastic
coatings allows little if any penetration into layers of
gravel which are commonly found on flat roofs. With the mastic
sitting on top of the gravel, little or no adhesion will
exist between the coating and the roof underlying the gravel.
The prior art mastic-type roof coatings described
hereinabove generally had to be quite thick, due to the
relatively low level of physical properties of the mastic
composition. Many of these mastic compositions were based upon
relatively low cost components, but because of the significant
amounts of material required to produce an acceptable waterproof
layer, the prior art coatings were not economical. Many leaks
in roofs were most difficult to patch with the prior art
coating compositions, especially in the case of gravel roofs.
8~
In order to insure the best roof patch, it w~s normally
necessary to remove the gravel from the area to be pa'~ched,
or else to put a coating of mastic over the entire roof.
Acrylic resins of the acrylate and methacrylate
type have been used for several decades in conventional house
paints, of both the flat and gloss type. Normally the paints
will exhibit a pigment volume concentration, or PVC, of at
least 18 - 20, and in the case of flat paints, the PVC may be
as high as 50-65 or evèn higher. Such high levels of pigment
generally result in relatively poor extensibility properties
of the resulting film. The prior art has been reluctant to
utilize acrylic resins at a PVC level below about 20, as the
resulting paint generally has poor hiding power, such that
it would not be considered a satisfactory paint.
U. S. patent 3,142,578 is directed to a finish
coat for roofs, and is based on an asphalt emulsion, glass
fibers, and hogs' hair. The asphalt emulsion has a high solids
content, and is used in very high amounts in the final
composition, so that the final content of asphalt in the
coating may be as high as 60% or so. The patent teaches that
the use of hogs' hairs is absolutely necessary in order to obtain
an acceptable coating, and that the asphaltic emulsion alone can-
not be used as a final sealing coat, as the resultant film checks and
pin holes and has other imperfections develop (note column 2,
lines 23 - 26). Various types of asphaltic emulsions can
be used, of the nature described at column 5, lines 3 - 26.
U. S. patent 3,741,922, discloses aqueous latex
paint compositions which are an intimate blend of cellulose
esters. U. S. patent 3,725,3~8 discloses latex coa~ing
compositions adapted for airless spray applications, having
pigment volume concentrations in the range between about
45% and about 70~. A number of various types of latexes
can be used, including acrylic polymer and copolymer latexes.
U. S. patent 2,372,108 relates to viscous
thixotropic emulsions of acrylate and methacrylate polymers.
The polymers are prepared by use of cation-active emulsifying
agents, used in a particular manner of polymerizing the
corresponding monomeric materials to form the acrylate or
methacrylate polymer.
U. S. patent 3,810,852 discloses thixotropic
aqueous dispersions of polymers suitable for use as emulsion
paints, wherein the thixotropic agent is a zirconium
carbonate complex. U. S. patent 3,955,997 discloses a
semi-solid emulsion coating composition containing a polymeric
component, including acrylic resins, a water-soluble organic
solvent, a thixotropic material, and a hydrophilic polymer,
such as certain cellulose derivatives.
8~2
U. S. patent 3,849,357 discloses pigmented masonry
water-repellant compositions, which compositions contain
pigment, acrylic polymers, and a silicone resin.
U. S. patent 3,950,283 discloses the production of
multi-colored paint, by admixing two or more differently
colored hydroxyethyl cellulose-containing aqueous polymer
emulsions, together with a clay dispersion, to form a
dispersion wherein the aqueous polymer emulsion particles
are the disperse phases in a continuous phase of the clay
dispersion.
U. S. patent 3,505,509 discloses a rubber latex
roofing composition. The roofing composition also includes
glass fibers, and can contain a surface active agent,
an antioxidant, a filling agent, a thickening agent, a wetting
agent and a curing agent. Normally the latex constituent is
employed in a ratio of 1.2:1 to about 1.5:1 with respect to
the glass fiber constituent.
U. S. patent 3,799,902 discloses a coating compo-
sition containing sodium aluminate, and a dispersion of a
polymeric latex based on an anionic vinyl-addition polymer,
and a water-soluble cationic polymer. The total amount of
polymer present in the dispersion is indicated to be within
the range of .001% to 75~ by weight. The coating composition
is indicated as suitable for forming films which can be cast
on surfaces such as glass or metals, or can be used for coating
fibers, or corrosion-resistant coatings.
SUMMARY OF THE INVENTION
The present invention is directed to a composition
for applying elastic, waterproof, long-lasting coatings to
roofs and walls of buildings. The composition has an
ultimate elongation of at least 250%, when measured in the
for~ of a dried film 7 mils thick and at 90% R.H. and 78~F,
a visco-elastic flow such as to permit a 7 mil thick film
which is firmly adhered to a surface to withstand, without
loss of the waterproofing characteristics of the film, the
development of a crack of up to 1 millimeter in width in
said surface, while maintaining firm adherence to the
surface immediately adjacent the crack, even over extended
periods of time, up to as much as 10 years in length, and
an adhesion, under both wet and dry conditions, when applied
to tar, gravel and paper-built roofs, cement tile roofs,
plywood roofs and asphalt roofs, such as to prevent the
passage of water between the coating and the roof.
The composition is based upon a polymer-rich
latex. The composition has a pigment volume concentration
(PVC) no greater than 10 and has substantially the maximum
possible content of polymer. The polymer latex preferably
contains at least 50% by weight of polymer, and the
composition contains at least 40% by weight of polymer.
The present invention is based on the discovery that
by using resins of a particular nature, especially acrylic
resins, which are not generally considered to be particularly
economical resins, and by using higher resin contents than
previously utilized by the waterproofing paint industry,
the physical properties of the resulting coating are
unexpectedly increased to the level that such low amounts
of the coating are required that the resulting cost of the
coating composition, on an applied basis, is most advantageous
with respect to the prior art coating compositions acknowledged
above. In this regard, it should be appreciated that by
applying enough of even a quite marginal waterproofing compo-
sition, a coating can generally be obtained which willinitially satisfactorily exclude water. However, it will be
readily appreciated that it is not practical to apply a
coating six feet thick of a marginally acceptable coating
composition in order to waterproof the flat roof of a building.
The waterproofing coatings produced in accordance
with the present invention will give protection extending up
to ten years and more to roofs~ if properly applied, and
cracks and leaks in existing roofs can be most readily patched
with the coating composition of the present invention. Roofs
which have been coated with the composition of the present
invention may substantially develop cracks therein, but the
elasticity and adhesion properties of the coating composition
of this invention permit the coating itself to withstand
cracks of greater than 1 mm in width, up to 2 mm. in width,
and even up to 4 mm. in width, without rupture. This is a
significant advance over the properties exhibited by prior
art waterproofing compositions.
z
DETAILED DESCRIPTION OF TEIE INVENTION
A number of various film-forming latexes can be
utilized as the polymer latex of the present compositions.
Homopolymers, copolymers and terpolymers can be employed
in the present compositions, as will be clear to the art.
Ordinarily these latexes are made by emulsion polymerization
of ethylenically unsaturated monomers. Suitable emulsions
include those of vinyl resins including vinyl acetate, vinyl
chloride, vinylidine chloride and the like, and acrylic
latexes including polymers and copolymers containing units
of acrylic acid, methacrylic acid, their esters and acrylo-
nitrile. sroadly, suitable latexes are latexes containing
elastomeric synthetic polymers which are obtainable in stable
aqueous latex form, containing at least 50% of the polymer in
the latex, and capable of coalescing into a film when applied
to a surface at ordinary room conditions, such as, for instance,
75%F and 25% relative humidity and at one atmosphere total
pressure. It is critical that the polymer latex be chosen
such that the resulting composition has an ultimate elongation
of at least 250% when measured in the form of a dried film
7 mils thick and at 90% R.H. and 78F. Furthermora, the
resulting dried film must be in a form such as to exhibit
the desired elastic and adhesive properties to permit a
7 mil thick film which is firmly adhered to a surface to
withs~and the development of a crack up to 1 mm. in width,
preferably up to 2 mm. in width, and more preferably up
to ~ mm. in width, in the surface without significant loss
of waterproofing properties thereof, even over extended
periods of time, including periods of time up to ten years
or so. The adhesion of the polymer latex composition should
be such that when applied to various types of conventional
roofs the dried film will prevent the passage of water between
the coating and the roof.
The polymer latex of this invention should tolerate
water, hydrophilic protective colloids and thickeners such
as water-soluble hydroxyethyl cellulose, carboxymethyl
cellulose, sodium caseinate, natural gums such as gum
tragacanth, locust bean gum, guar gum, and alkali metal
alginates, various surfactants such as anionic surfactants,
e.g., sodium dodecylbenzene sulfate and sodium dodecylbenzene
sulfonate, and nonionic surfactants such as alkyl phenoxy
poly(ethyleneoxy)ethanol having alkyl groups of about 7 to
about 12 carbon atoms and the like, ampholytics such as
coconut fatty acid amides, coconut fatty acid amide condensates
and the like, freeze-thaw recovery agents such as the lower
alkylene glycols,alkali-fast colorants such as Hansa yellow
dyes, phthalocyanine blues and greens, red or yellow oxide
or iron toners and toulidine reds, and the like. The latex
coating composition of the present invention may be manufactured
-- 10 --
~8~
with some or all ingredients, i.e. freeze-thaw stabilizers,
coalescents, antifoams, and can also include fungicides,
other stabilizer-thickeners such as hydroxyethylcellulose,
and various other anionic and nonionic surfactants.
The coating composition of the present invention is
preferably based on an acrylate polymer latex, wherein the
acrylate polymer is a lower alkyl ester, such as a methyl,
ethyl or butyl ester, of acrylic and methacrylic acids,
and copolymers of such esters with other ethylinically
unsaturated copolymerizable monomers which are known to the
art to be suitable in the preparation of acrylic polymer
latexes, can also be utilized. Suitable comonomers include
vinyl acetate, which may be used as a comonomer with, for
instance, butyl acrylate in a ratio of 70/30 or smaller of
the vinyl acetate to the butyl acrylate. Various cross-
linking agents known to the art may be utilized, such as,
for instance, trimethylolpropane triacrylate.
It is critical that a polymer be chosen which can
be utilized at the maximum possible level in the coating
composition, and the minimum amount of polymer in the
composition will be about 40% by weight. Preferably, at
least about 45% by weight of polymer will be in the aqueous
coating composition. Such high resin contents in the coating
composition can be obtained by using a latex containing at
least 50% by weight of polymer, and preferably the latex
8~
contains at least 55% by weight of polymer, more preferably
at least 60% by weight of polymer.
The maximum content of polymer in the composition
is obtained by using polymer latexes containing the high
polymer contents mentioned above, and also by using the
minimum amount of other agents, and especially by avoiding
- the addition of unnecessary amounts of water to the composi-
tion. A thixotropic thickening agent may be added in the
minimum amount to give the desired viscosity, and the
minimum amount of coloring agent required to produce a desired
level of coloration may be utilized. A coalescing agent
may be added for the acrylate polymers in an amount which is
the minimum amount to produce the desired coalescence of the
polymerO --
Normally the amount of non-polymer non-aqueous
constituents will be less than 20% by weight, with a strong
preference for these additives being less than 15% by weight,
especially less than 10% by weight, based on the weight of the
final coating composition. By so minimizing the quantity of
constituents other than film-forming polymer in the dried
film, the resulting film will exhibit the desired flexibility
and durability.
The coating composition is normally covered by an
acrylic paint or other conventional paint after drying, for
tack reduction purposes and also for a more attractice
appearance.
- 12 -
The purpose of the coloring agent in the coating
composition is to allow the workmen in the field to determine
which areas have been covered, and which have not yet been
covered, by the coating composition during the application
thereof. After the coating composition has dried, any
uncoated areas should be readily detectable. In addition,
at least in some instances the workmen in the field will be
able to obtain a rough idea of the amount of composition
which is being applied. Thus, the amount of coloring agent
which may be added is only enough to distinguish the freshly
applied coating composition from the uncoated substrate.
It is critical that the coating composition have a PVC or
pigment volume concentration no greater than 10, in order to
maintain the high acrylate polymer concentration. Preferably,
the PVC of the coating composition will be less than 6, and
more prefexably if pigment is used the PVC is in the neighborhood
of 4.
The coloring agent is preferably a pigment, more
preferably titanium dioxide, such as Rutile titanium dioxide.
However, other pigments which are chemically inert to the
acrylate polymer may be utilized, and dyes may be utilized,
although the use of dyes, which are known to have relatively
poor ultraviolet resistance, is not preferred. When only
dyes are utilized, the PVC may be 0.
For applications to other than gravel roofs and
to walls, it is preferred that at least one thickening agent
which imparts thixotropic characteristics to the composition
be used. Attapulgite clay has been found to be particularly
- 13 -
8~
effective, although other ~hixotropic thickening agents
known to the art may be utilized if desired.
When the coating composition is used to coat a
gravel roof, normally little or no thickening agent will be
S utili~ed, as it is preferred for the coating composition to
then be of a very low viscosity, in order to penetrate through
the gravel to the surface of the roof. In fact, the coating
composition of the present invention will frequently be
diluted with water up to 50~ by volume, preferably about
20% by volume, for such applications, in order to reduce
the hangup of solid components on the gravel.
For other coating applications, howeverc it is
preferred that the coating composition be thickened to the
point so that after application little if any flow will
occur. Of course, with the thixotropic thickening agents,
the coating viscosity will reduce upon the application of
shear, so that the coating may be readily applied by con-
ventional techniques. Once the coating is applied to walls '
or roofs, however, it is preferred that it remain substantially
in the place of application, without significant sag or othermovement. Within these parameters, those in the art can readily
choose appropriate thickening agents, and the appropriate
amounts of such thickening agents.
8~2
The coalescing agent may be any conventional
coalescing agent for acrylate polymers, but a coalescing
agent which has been found to be particularly suitable
is 2,2,4-trimethyl-1,3-pentanediolmonoisobutyrate. Normally
; the coalescing agent will be used in an amount of less than
5~ by weight, preferably less than 3% by weight, and more
preferably about 2.5% by weight.
Some types of film-forming polymers do not require
the presence of a coalescing agent under certain conditions,
1 as known to the art, so that it will be readily appreciated
that the use of coalescing agents is optional.
In certain instances it may be desired to incorporate
fibers, such as asbestos fibers or glass fibers, into the
coating composition to increase the tear strength of the
~'- thin films of the coating. This approach might be more useful
for roofs wherein subsequent crack development of significant
magnitude was expected, as the incorporation of the fibers may
permit the coatings to resist failure in spite o~ the develop-
ment of even wider cracks than the 4 mm. cracks mentioned above.
O The coating composition may be sprayed upon roofs
and walls, or may be brushed or applied by a roller. Normally,
the coating composition will be applied in two coats, to
insure full coverage, with the coats cross-lapped to insure full
coverage. A total coverage rate of 70 square feet per gallon
``~ will result in a coating thickness in the order of 10 mils,
which has been found to be quite satisfactory. Normally,
the coating composition should not be less than 2-4 mils
in thickness, in order to obtain ade~uate physical properties,
resistance to pinholing and the like. There is no real upper
limit on the coating thickness, other than limitations imposed
by economic considerations and by the maximum design weiyht
which the roof can withstand. secause of economic factors,
however, it would be most unusual to have a coating as thick
as 50 mils, and it is preferable that the coating be no more
than 20 mils in thickness. These thickness ranges do not
account for the thickness of coating composition requixed to
patch a crack, of course.
In addition to the critical ingredients set forth
above, the coating composition of the present invention will
normally have other conventional paint additives therein.
For example, the coating composition generally contains one or
more wetting agents, dispersants, fungicides, sticking agents,
defoamers, and the like. It is helpful to utilize a basic
dispersant to disperse the titanium dioxide or other pigment
in the coating composition. The presence of a fungicide is
particularly recommended in hot, humid climates, although
for more northern climatic conditions, the presence of a
fungicide will normally still be recommended, in view of the
long potential life of the coating composition of this invention.
The presence of a sticking agent will assist the composition
- 16 -
to adhere to greasy or glassy surfaces, and thus will be
helpful for some applications. The presence of a
defoamer is particularly useful to avoid foaming problems
and the defoamers which may be utilized are conventional~
The coating composition of the present invention
has its outstanding utility when used as a waterproofing
agent`for roofs, but is also useful in waterproofing walls.
The surfaces which may be coated with the composition of the
present invention include cement tile roofs, gravel roofs,
) asphalt shingle roofs, wood shingle roofs and walls, tar-
paper roofs and walls, cement walls, brick walls, masonry
block walls, plywood walls and roofs, and any other exterior
or interior building surfaces to which adequate adhesion
is obtained. The products which are presently cornmercially
; available are generally satisfactory as waterproofing coatings
for walls, as long as the wall does not crack. However, the
products now available are generally subject to coating failure
if a crack of any magnitude develops in the wall. In contrast,
the coating produced from the composition of the present
O invention will stretch and retain its waterproofing ability,
even if cracks of 1 mm. in width or greater develop in
the coated wall.
; The present coating composition is based on the
use of a minimum amount of water, commensurate with the
production of a stable latex, and also for certain applications
with the viscosity reduction of the composition to the point
- 17 -
8~
where desired penetration ~hrough gravel can be obtained.
If too great a dilution with water is used, the shrinkage of
the composition during drying will be too great, and the
properties of the resulting dried film will be adversely
effected.
For almost all other applications, however,
to other types of roofs and to walls, the concentrated
composition, such as a product of Example 1, having maximum
resin content, will be utilized.
When the resin coating is applied to a gravel
roof, to penetrate through the gravel to the underlying
substrate, in some instances the gravel may have had enough
dirt penetrate through it that the resin will basically
adhere to a dirt layer, rather than the underlying roof
surface. In any event, the polymer must exhibit an adhesion,
especially a wet adhesion, such as to adequately resist any
tendency to separate from the surface to which it is
adhered.
As indicated, it is preferred to utilize a
thickening agent in the coating composition of the present
invention, with the sole exception of coatings which are
to be applied to gravel roofs, and it is quite preferred that
at least one of the thickening agents utilized impart
thixotropic characteristics to the composition. The ultimate
viscosity and the thixotropic nature of the composition will
- 18 -
vary, depending upon the particular end use which is
contemplated, and also depending upon the particular method
of application to the substrate that is contemplated. For
instance, a higher thixotropic ~iscosity can be utilized
for spray application than for roller application, thus
permitting greater build-up on walls and similar surfaces
during spray application.
As mentioned hereinabove, in some instances it
may be desirable to incorporate fibrous reinforcement into
the coating composition, to increase the physical properties
of the dried films. ~owever, when the coating composition is
to be applied to gravel roofs, it is definitely preferred that
the coating composition contain no fibrous components, as
such components would hang up in the gravel layer and thus
would not form a significant function in the waterproofing
coating formed on the underlying substrate. For most
applications it is preferred that the coating composition
be in the non-fibrous form - that is, that no fibers or
filaments be incorporated therein.
The elasticity of candidate coating compositions
may be readily tested by determining the Mar Elasticity
Value thereof, using the following procedure. A conventional
asbestos cement shingle, such as a shingle 1/8" thick, is
liberally coated on a smooth side thereof with a sealer
~4CRy,~ D ~
2`5 (such as ~ B-72, an ethyl methacrylate copolymer
Q~k
-- 19 --
produced by Rohm and Haas, havingla T of 40C and a viscosity
of 470-770 cps at 25C in the form of a 50% toluene solukion,
dissolved in xylol to a 12~ resin content). After l hour
of drying time, the sealer-coated surface is spray coated
in two spray applications with the candidate waterproofing
composition to a total film thickness of 7-lO mils, dry
basis. The thus coated shingle is permitted to dry under
ambient conditions for 7 days.
The asbestos shingle is then broken, from the
uncoated side toward the coated side, and the two shingle
sections on either side of the crack are moved apart
increasingly greater distances, and the film checked for
integrity at each such distance. This provides an indication
of the initial crack development resistance, or elasticity in
use, of the candidate waterproofing composition.
The viscoelastic flow characteristics of the
candidate waterproofing composition film are checked by
taking similar broken, coated asbestos cement shingles and
clamping the two sections in rigid clamps maintained a
fixed distance apart, with the film integrity observed over
the desired periods of time. A Mar Elasticity Value is
the width, in~mm.r of a crack which the candidate waterproofing
~-~ composition fj~ ~E (7 mils thick) can withstand over a period of 1
month or more, without loss of waterproofing characteristics
and without significant loss of adhesion to the shingle.
- 20 -
The waterproofing coating composition to the
present invention will have a Mar Elasticity Value of
at least 1, and preferably at least 2. In some instances
the compositions may have a Mar Elasticity Value as high
as 4 or even higher. In contrast, a conventional flat
latex paint may have a Mar Elasticity Value of 0.25, or
even less. Thus, with the high Mar Elasticity Value
exhibited by the present coating compositions, the compositions
are able to withstand, in the form of dried ~; significant
crack development in the underlying surface.
An unexpected advantage of the polymer-rich
waterproofing coating compositions of the present invention
is that the conventional fungicides used therein are much
more effective, at a given level of fungicide in the resulting
; 15 film, than in compositions having conventional PVC values,
i.e. PVCs of 20 and greater, and the present compositions are
especially much more resistant to fungus attack than flat
paints of 50 PVC or more containing corresponding amounts
of fungicide. While this observation appears true for
any conventional fungicide, it has been found to be of particular
advantage with mercuric fungicides, such as phenyl mercuric
succinate or phenyl mercuric acetate. Normally the
fungicide will be used in the coating composition in an
amount of about 1-2 lbs., based on active metal, such as
mercury, per 100 gallons of coating composition, although
in some instances the fungicide level may be as low as 1/2
lbs. of active metal per 100 gallons of composition, and
there is no technical reason why greater amounts of
g~
fungicide cannot be used, but economic considerations
generally dictate that no more than 2 or 3 lbs. of
fungicide based on active metal will be used per 100
gallons of composition.
An illustration of the greatly increased fungicidal
activity which can be obtained will be noted if a coating
composition of the present invention is compared to a
conventional flat paint having a PVC of perhaps 60, using
the same film-forming polymer in the two compositions, and
the same type and amount of fungicide therein. The conventional
flat paint may be subject to substantial fungus attack
after only four months of Southern Florida exposure,
whereas the coating of the present invention may show no
signs of fungus attack after two years or more of the same
exposure.
The art has experimented with the concept of
reacting the active fungicide onto the film forming polymer
or other coating compositions, and if such attempts are
successful, no reason is seen why the same concept could
not be used in the coating compositions of the present
invention.
- 22 -
~8~3~2
EXAMPLES OF THE INVENTION
Example 1
A 100 gallon acrylic-rich coating composition was
prepared by adding, in order, the following ingredients to
a stirred mixing vessel:
Water 7 gal.
Potassium tripolyphosphate60 gms.
AMP-95 amine dispersant (2-amino-
l-methylpropanol, International
Minerals and Chemicals)200 ml.
Attagel-50 thickener (Attapulgite
- clay, Englehart Industries) 14 lbs.
T~itaLnium dioxide, Rutile type 25 lbs.
R~lC2~ AC-64 acrylic latex (60
aqueous dispersion of methyl
methacrylate copolymer r Rohm &
Haas) 80 gal.
The following ingredients were mixed together in a
separate mixing vessel:
Super Adit fungicide (phenylmercuric
succinate, Tenneco Chemicals) 18 lbs.
Texanol coalescent agent (2,2,4-
trimethyl-1,3-pentane diol
monoisobutyrate, Eastman
Chemical) 23 lbso
AMP-95 amine dispersant2 lbs.
Water 5 gal.
After the above ingredients in the second mixing vessel were
thoroughly mixed, they were added to the main batch of material
in the first mixing vessel. This procedure prevented undue
shocking of the system, which would tend to cause precipitation.
~ r~ k
- 23 -
8~
j
Thereafter, to the above mixture the following
ingredients were added:
GR-7M sticking agent (a 64%
aqueous dispersion of
dioctylsodium sulfosuccinate,
Rohm & Haas) 29 5 oz.
F-142 defoamer (Tenneco Chemicals~ 64 oz.
Thereafter, in a separate mixing container, 270 grams
of J12 MS thickener (hydroxypropylmethylcellulose, Dow Chemical)
and 64 oz. of water were mixed together, and then added to the
stirred main batch.
The acrylic-rich coating composition produced by this
example was highly suitable as a waterproofing coating for
roofs, especially roofs built up of various layers including
gravel. The coating composition could be sprayed on a cement tile
roof and the viscosity of the coating composition was such
that it would stay in place after application, and would coalesce
thereon to form the desired waterproof coating. This coating
exhibits excellent adhesion to various substrates, and has a
high degree of elasticity, compared to conventional latex
paints and other waterproofing coatings for roofs. That is,
the coating appeared to have maximum stretch and resiliency,
commensurate with coating strength. Thus, the coating could
withstand significant crack development in the roof after
coating application, up to 2mm. wide crack development, without
resulting in coating failure and water leakage. Excellent
adhesion could also be obtained on conventional tar roofs,
and the coating composition has excellent penetration of
moderately chalky surfaces.
- 24 -
The p~esent coating compositions are suitable
for application to below-grade walls, and in particu~ar
a test coat has been applied to the inside masonry block
wall of a below-ground basement, wh,ich previous to such
application had exhibited leaks. The application of the
coating of Example 1 to form a coating about 10 mils thick
appeared to adequately stop the water leaks in the test area.
It does appear to be important, for applications wherein the
water, or hydrostatic, pressure on the film would tend to
push,the film away from the substrate to which it is adhered,
for adequate keying of the film to occur in the substrate.
In other words, a relatively porous masonry block construction
substrate would be definitely preferred over a smooth finished
poured concrete wall.
With the open pore structure of the substrate,
the resin can enter into various pores and intersticies
therein, and obtain firm adherence by keying. The dried
film will still permit moisture vapor to pass therethrough,
and can be finished with a top coat of acrylic or other paint,
which can be conventional or textured as desired. Thus,
an attractive interior finish can be achieved, while at the
same time waterproofing of the walls is accomplished.
Example 2
Example 1 was repeated, but the Attagel attapulgite
clay was increased to 20 lbs. and the J12MS was increased to
- 25 -
1800 gms. This resulted in a coating composition which
had a pasty, barely pourable viscosity which could ~e
thinned upon the application oE shearing forces thereto.
The thick coating composition of this example was highly
suitable for patching cracks in existing walls and roofs,
wherein the viscosity was at the stop-flow level.
To repair a roof having wide cracks therein, it
is preferred that the cracks be patched with a conventional
patching composition, in order to provide structure to
support the coating composition of this invention, and
then the crack is covered with the composition of this Example
2. Thereafter, the entire roof is preferably covered with
the composition of Example 1. After these compositions have
dried, it is then preferred to coat the entire roof with
a conventional acrylic exterior paint, because of the
relatively sticky nature of the dried coating of Example 1,
caused by the high resin content.
The above compositions were formulated for use
in Southern Florida and may require some modification for
use in other areas having different environments, as
will be clear to those in the art.
- 26 -
