Note: Descriptions are shown in the official language in which they were submitted.
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ACRYLIC POLYMER PORTLAND CEMENT COATING COMPOSITION
Background of the Invention
(1) ~ield oP the Invention
This invention relates to improving -the flexibility,
abrasion and heat resistance and particularly shear bond
(adhesive) characteristics of acrylic polymer Portland cement
coating compositions.
(2) Descrlp-tion of the Prior Ar-t:
The prior art is represented by U.S. Patent 4,263,372,
which discloses the use of dicyclopentenyl acrylic or methacrylate
or a mixture thereof as a hydrophoblc binder material in various
particulate aggregate sys-tems in conjunction with cementitious
materials such as hydraulic cements.
Patent 4,329,822 discloses a filled polymeric wall facing
unit in which a polyester composition such as unsaturated poly-
merizable polyester resin filled with sand as a sui-table filler
material and wherein the polymeric composition is applied to
a building block which may be of concrete.
Patent 4,031,282 discloses a similar coating material
incorporating a polyester resin or the like for application to
improve the esthetic appearance of the object coated.
A number of patents have been issued wherein the use of
a polymer in a cement is disclosed. See for example U.S.
Patents 2,648,645, 3,239,479, 3,937,633, 4,060,425 and 4,211,572.
In Patent 2,648,645, polyvinyl alcohol in a Portland cement
composition is disclosed as being capable of reducing water
loss from a slurry.
28 Patent 3,937,633 discloses the use of a polymer in a
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cement slurry for reducing the water ]oss theIefrom.
Patent 3,239,~79 cliscloses a Portland type cement contain-
ing a latex, such as a polymer, in which the composition is
intended -to retard the setting time of the composition.
Patent 4,060,~25 discloses a Portland cement mixture
incorporating a halogen atom with one or more short range
strength accelerators such as calcium alumi.nate and ethylene
glycol together with a bituminous emulsion. The patent discloses
the substitution of a rubber latex and a resin emulsion -for
the bituminous material and the result obtained is a rapid
hardening cementitious mixture. The product is noted as being
useful as a grout whi.ch has elastic properties for a slab-type
track structure.
Patent ~,211,572 discloses a dry se-t mortar in which the
water retentive agents such as cellulose ethers are improved
by the addition of small amounts of ethylene glycol or the
like. The present invention produces a Portland cement coating
composition consisting of sand, Portland cement,an acrylic
polymer, a defoamer and a critical amount o-f propylene glycol.
The resulting coating material has an unusual and unexpected
shear bond characteristic when applied to concrete, wood, hard-
board, metal, glass and other materials with unusual and unexpected
flexibility along with high abrasion and heat resistance. The
addition of a coloring agent to the coating composition such
as any of the food coloring agents commercially supplied in
an aqueous solution usually incorporating propylene glycol
enables the essential propylene gylcol ingredien+ and -the color
28 ingredient to be combined and added to the composition and wherein
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the color ingredient provides color coding in the mixture when
the composition is mixecl with water to provide the desired
consis-tency for application to -the article being coated, for
example a low slump consistency suitable for resurfacing
concrete walkways, pavements, and -the like, the color coding
serving during the mixing process to indicate the presence of
a desirable amount O:e water in the mixture with the color
carrying over into the set coating and eventually disappearing.
Summary of the Inven-tion
A consistently fle~ible acrylic polymer Portland cement
coating composition having unusual shear bond (adhesive)
characteristics and unusually high abrasion and heat resistance
is capable of safe and economic manufacture and can be con-
veniently mixed to a desired consistency with water and used
in coating many materials to provide a highly desirable weather,
wear, and heat resistant coating that remains bonded to the
substrate material despite flexing of -the same,incorporates sand,
; Portland cement, acrylic polymer, propylene glycol and a defoamer,
a typical batch may comprise 53 6% by weight sand, 30.7% by
weight Type I Portland cement, either white or gray, 6.3%
acrylic polymer, .015% propylene glycol, . 2/o defoamer and 9.11%
water. The propylene glycol may and preferably does contain
a color additive.
Description of the Preferred Embodiment
The composition of -this invention is a material which may
be generally termed an acrylic polymer Portland cement coating
composition particularly suitable for forming thin, unusually
28 durable coatings on concrete such as sidewalks and pavements,
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concrete bloclc walls, wood panels, hardboards, metal panels
as used in walls, floors, ceilings and roo~ structures in
various constructions and glass panes or panels such as for
example where a light blocking coating is applied to part o~
a glass pane or panel in a decorative manner with the coating
material remaining permanently affixed to the glass pane or
panel by its unusual shear bond characteris-tic.
The composition of this invention in a typical wet mix
batch totaling 26.10 pounds incorporates 141bs. oI sand, 8
lbs. o~ Po.rtland cement (white) Type I,1.681bs. acrylic polymer,
1.60 grams propylene glycol, 20 grams liquid defoamer and 38
ounces of water , the acrylic polymer is a water dispersion
with the acrylic solids comprising 48%. ~ suitable acrylic poly-
mer is commercial available as R~IOPLEX ~qC-76 ~rom Rohm and IIaas
Company of Philadelphia, Pennsylvani.a 19105, and the defoamer
is a liquid commercially available as NOPCO NXZ (100% active~ from
Process Chemicals Division of Diamond Shamrock Corporation.
Morristown, New Jersey 07960. Dimethylpolysiloxane is suitable.
. The sand in the foregoing example is pre~erably silica sand,
known in the trade as No. 1 ~ ROC D~Y as commercially available from
Pennsylvania ~lass Co;, Pittsburgh, Pa. 15235, a san~blasting grade.
The Portland cement Type I white is commercially available
from Medusa Cement Company, Division o~ Medusa Corpora-tion.
Cleveland, Ohio.
The propylene glycol is an aqueous solution in which the
propylene glycol comprises 16% by weight with a 2.5~o coloring
agent added. It is available from Durkee Famous Foods, Division
~8 f SCM Corporation, Cleveland, Ohio.
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The acrylic polymer herein referred -to may be an acrylic
resin such as a thermal plastic polymer or co-polymer o-f acrylic
acid, methacrylic acid, esters of these acids or acrylonitrile.
The propylene glycol herein referred to may be 1,2 propylene
(1,2 dihydroxy propane), 1,2 propanediol, methylene glycol,
or methyl glycol, and acts as a wetting agen-t, humectant and
emulsifier in modify.ing the acrylic pol.ymer so as to enable
it to coat each grain of the silica sand in the wet mix of the
Portland cement coating composition and flexibly bond the sand
with the finely divided Portland cement par-ticles.
In preparing the cement coating composition, thoroughly
premix the sand and cement, thoroughly blend together the wa-ter
dispersion of the acrylic polymer, the aqueous solution of the
propylene glycol, the liquid defoaming agent, and -the water,
and add to the premixed sand and cement. The entire composition
is then mixed thoroughly for from three to four minutes. The
water content may be varied to obtain the desired consistency
for the coating application, that is, trowel or spray. This
is best performed by withholding a portion of the water from
the initial mix and adding it as necessary to obtain the desired
consistency of the coating composition.
The amount of acrylic polymer in the above example is
based on cement weight and desired results. Acrylic dispersion
to cement ratio would be a minimum of 10% and a maximum of ~0%.
The percentage of the propylene glycol to acrylic po]ymer is
.001 and .002. The Portland cement content of the composition
is relatively high compared with the usual ~ortland cement mixes.
2~ It has been de-termined that the desired performance
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properties as hereinbefore set :forth ancl con-firmed by a labora-
tory report hereinafter given, are controlled by the amount of
propylene glycol modifying the acrylic polymer.
An alternate composition having -the same unusual and un-
expec-ted characteristics as the foregoing example may comprise
the substitution of Portland cement gray Type 1 -for the white
Portland cement of the above example. The Portland cemen-t
gray Type 1 is also commercially available from ,~ledusa Cement
Company.
The prior art relating to cemen-t additives such as acrylic
polymer, is illustrated by a publication copyr:ighted in 1980
by Rohm & Haas Company with respect to its RIIOPLEX (trademark)
E-330, a cement mortar modifier. This publication states that
cement mortars modified with the product are hard, tough, and
durable and compared with unmodified mortars, polymer modified
mortars have superior flexural, adhesive and impact strength
as well as excellent abrasion resistance. Proper-ties of Portland
cement rnortars to which the Rohm & Haas polymer were added are
reported with respect to compressive strength utilizing the
American Society for Testing and ~laterials Test Standards
with a sample of the concrete after a 28 day dry cure showing a
reading of 5,450 p.s.i. A sample of -the Portland cement coating
composition of the present invention -tested in Pittsburgh
Testing Laboratory utilizing the same test method of the 28 day
air cured test samples showed an average reading of 5,~10 p.s.i.
which is substantially the same as the Rohm & Haas reported test.
On flexural strength, again using a 28 day air cured sample,
28 and the same Rohn & Haas test methods, the Rohm & Haas publica-
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tion repor-ts a reacling of 1,355 p.s.i., whereas the Pittsburgh Testi~g
Laboratory Test average on 28 day samples of the gray composition
of the present invention showed a reading of 1,~70 p.s.i. and 3700 p.s.i.
on the white cement composition after 7 days air cure; a sub-
stantial improvement.
On shear bond adhesion, the Rohm & lIaas publication reports
tests on a. 28 day air cured sample showing a reading of 500
PSI whereas the Pi-ttsburgh Tes-ting Laboratory report on -tests
of the material of the present invention in -two samples 28 day
10 air cured, provided readings of 1,025 PSI and 1,087 PSI, respec-
tively, showing the obvious superiority of the Portland cement
composition of the present invention.
On abrasion resistance, the Rohm & Haas publication
reported tests on 28 day air cured samples showing material
loss of 1.70 grams, whereas the Pittsburgh Testing Laboratory reports
on the Portland cement composition of the present invention
showed a loss of only 1.1183 grams which is nearly half the
material loss of the Rohm & IIaas test sample and shows the
obvious superiority of the Portland cement coating composition
20 of the present invention.
Those skilled in the art will observe that a Portland
cement coating composition having the unique and unexpected
characteristics of the composition of the present invention
makes possible the production of considerably improved precast
Portland cement wall, floor and roof panels for use in building
constructions which are :relatively thin with respect to their
overall area and thickness and are frequently used as exterior
28 surfacing materials directly exposed to temperature and weather
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changes.
The material of the present inven-tion in addition to -the
highly desirable and unexpec-ted charac-teristics hereinbefore
noted has an unusual fire resistance characteristic. Tests
of the material subjected to a flame at 2300F. for fifteen
minutes showed no visual damage whereas Portland cement
compositions here-tofore known in the ar-t erup-t, crack, and
show visual deterioration at considerably lower -tempera-tures.
Applications of the acrylic polymer Por-tland cemen-t coa-ting
composition of the present invention are particularly useful in
forming Portland cement based ornamental panels having pebble
carrying surfaces as the unusual and unexpec-ted shear bond
adhesion firmly locks the pebbles wllich may be various ornamental
rounded stones to the panel formed of the composition. Building
blocks, such as cement blocks and the like as known in the
industry, are advantageously provided with a coating of -the
present composition on one or more of their surfaces so that
a wall formed of these units has -the unusual characteristics
of the material.
Tests of the composition disclosed herein relating to the
thin coating and patching of aged,worn, cracked and eroded cement
sidewalks and pavements and extending for a period of more than
10 months and through a complete fall, winter and spring season show
no damage to the coated areas, no spalling and no breaking away of the
coating whereas comparable damaged concrete sidewalks patched
with conventional Portland cement mixtures, some including acrylic
polymers show substantially less shear bond adhesion with sp~lling,
2~ and breaking away of the coa-ting material in tests of the same
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duration in the same location and subjected to the same weather
and wear conditions.
The color codlng hereinbe-fore mentioned is advantageous in
applying the Portland cement coating composition herein dis-
closed, -for example utilizing a green food color additive to
the propylene glycol aqueous solution causes the mixture to
assume a blue color when too much water is added. When the
proper amount of water is added to achieve a desirable coating
consistency, the material takes on a dark green color changing
to amber green as the coating sets and in several days changing
again -to a light greenish brown which remains until the coating
material is subjec-ted to a thorough wetting down as irom rain
in a weather area, whereupon the iinal color is a light gray.
It will thus be seen that an unusual acrylic poly~er
Por-tland cement coating composition has been disclosed, which
due to its relatively high Portland cement content, high de-
foamer conten-t and the presence of a critical amount o~
propylene glycol produces a Portland cement coating material
with unusual and highly desirablè characteristics including
excellent compressive strength, exceedingly high ~lexural strength,
very high unexpected shear bond adhesion and retaining better than
normal tensil strength and impact strength and possessing an
unusually and unexpected high abrasion resistance. The material
is relatively inexpensive to form, relatively easy -to mix
and in the proper and desirable consistency, unusually
cooperative in trowel applications or spraying applications
due to :its extremely low slump and highly adhesive
28 characteristics.
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Changes in the amounts of acrylic po~ymer alld Portland
cement may be made within certain limits provided the ratio
of propylene glycol to acrylic polymer is maintained. For
example, the aqueous dispersion of acrylic polymer may be
used in amounts between about 5% to about 7% by weight of
the total composition and the Portland cement may be used in
amounts between about 23% to about 38~o by weigh-t of -the
total composition.
g Having thus described my inven-tion what I claim is:
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