Note: Descriptions are shown in the official language in which they were submitted.
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WATER REPE~LENT FOR M~SON~Y
Background of the' Invehtion
The present invention generally relates to the
treatment of porous materials in order to render them water
repellent. More particularly, the present invention
relates to silicone compositions suitable for rendering
masonry such as brick, concrete, stone, mortar, tile,
cinder block, stucco and the like water repellent and
stain resistant.
Silicones have been used to render masonry water
repellent for many years. The heretofore employed
silicones have met with considerable commercial success and
are used on all types of masonry. However, the heretofore
employed silicones tended to leave the surface of the
masonry somewhat tacky and hence caused dirt to adhere
thereto. Additionally, many of the previously employed
silicones did not maintain excellent water repellency
after prolonged exposure to weather nor did they impart
stain resistance to the masonry.
U.S. Patent No. 2,412,470 discloses a process
for treating a solid body to render it water repellent
which comprises contacting said body with a composition
containing, as the active ingredient thereof, a mixture
consisting essentially of from about 2.8 to 99.2 weight
percent trimethyl silicon chloride and from about 97.2
to 0.8 weight percent silicon tetrachloride.
U.S. Patent 2,574,168, issued November 6, 1951
to Brick, provides a process for rendering porous masonry
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structures water repellent by applying to such masonry
structures a dilute liquid comprising an organic solvent
solution of a silicone resin is in its B-staged partially
condensed form, wherein the concentration of the silicone
resin is from about 0.1 to 5 parts by weight, said
silicone resin when completely condensed being a hetero-
cyclic and crosslinked condensation product having the
formula (RmSiOn)X, where x is an integer greater than
one, R represents monovalent alkyl or aryl radicals,
m is a number less than two but not less than 0.5, and
n is a number more than one and not less than about
1.75, the silicon atoms in the resin being linked to
the oxygen atoms and the alkyl and aryl radicals being
attached to silcion atoms.
U.S. Patent 2,672,455, issued March 16, 1954
to Currie, provides a water repellent for leather which
comprises (1) 15 to 50 percent by weight of a titanium
compound selected rom the group consisting of titanium
compounds having the general formula Ti(OR)4 and
aliphatic hydrocarbon soluble partial hydrolyzates thereof
in which R is an aliphatic hydrocarbon radical or
hydroxylated aliphatic hydrocarbon radical, (2) 15 to 70
percent by weight of a methylpolysiloxane copolymer composed
of trimethylslloxane units and SiO2 units, said units
being in such proportion that the ratio of methyl radicals
to silicon atoms is from 1.0 to 2.5:1, and (3) 15 to 80
percent by weight of a polysiloxane having the general
formula Rln siO(4 n)/2~ where R is a Cl_4 alkyl or
alkylene radical or a monocyclic aryl radical, and n having
an average value of 2 to 2.9, each silicon atom in poly-
siloxane having at least one R' radical attached thereto.
U~S. Patent No. 2,678,893, issued May 18, 1954
to Kauppi, teaches a method for rendering leather water:
repellent comprising contacting the leather with a
solution of a methylpolysiloxane composed of trimethyl-
siloxane units and SiO2 units in such proportion that
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the ratio of methyl radicals to silicon atoms is from 1
to 2.5, said solution containing from 1 to 50 percent
by weight of the methylpolysiloxane.
U.S. Patent No. 2,735,791, issued February 21,
1956 to Peyrot et al, relates to a waterproofing composition
suitable for application to fibrous organic materials
which comprises an aqueous emulsion containing 20 to 60
weight percent, as solids, of a methyl polysiloxanic
resin having a CH3 to Si ratio between 1.3:1 and 1.7:1;
20 to 50 weight percent of a me-thyl polysiloxanic oil
having a C~3 to Si.ratio between 1.9:1 and 2.1:1; and
from 8 to 40 weight percent triethanolamine titanate.
U.S. Patent No. 2,928,798, issued March 15,
1960 to Brown et al, discloses compositions use-Eul for
rendering porous materials water repellent which comprise,
by weight, (1) from 10 to 60 percent of a titanium compound
selected from the group consisting of (a) orthotitanates
having the general formula Ti(OR)4, where R is an aliphatic
hydroearbon radical or an aminated or hydroxylated
sliphatic hydxocarbon radical, and (b) aliphatic hydro-
earbon soluble partial hydrol.yzates of (a); (2) from 25 to
75 percent of a methylsiloxane copolymer eontaining
trimethylsiloxy units and SiO2 units, where the rati.o
of methyl groups to silicon atoms ranges from about 1 to
1.25, and (3~ from 10 to 50 pereent of a fluid organopoly-
siloxane having the formula R'nSiO(4_n)/2, where R'
represents both lower alkyl radicals and chlorinated
phenyl radicals containing an average of 3 to 5 chlorine
atoms per phenyl nucleus, the chlorinated phenyl radicals
constituting from 5 to 25 percent of the total number of
R' radicals, n has an average value between 1.96 and 2.5,
and the viscosity is from 10 centistokes to 100,000
centistokes at 25C.
'Summa'ry'of't'he Inven*ion
It is an object of the present invention to
provide methods and compositions for rendering masonry
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water repellent.
It is another object of the present invention
to provide masonry water repellent compositions which
cure to a dry, non-tacky material.
Still another object of the present invention
is to provide masonry water repellent compositions which
also impart stain resistance to the masonry material.
An additional object of the present invention
is to provide a masonry treatment which will remain
effective for an extended period of time under severe
weather conditions.
In its broadest aspect, the present invention
provides a method for rendering masonry water repellent,
comprising contacting the masonry with a solution comprising
an organopolysiloxane resin selected from the group con-
sisting of resins containing R3Sioo 5 units and SiO2 unit,
the ratio of R3SiOo 5 units to SiO2 units ranging from
about 0.2 to about 0.9:1 (e.g. MQ resins), and resins
containing R3SiOo 5 units, R2SiO units, and SiO2 units,
the ratio of R3SiOo 5 units to SiO2 units ranging from
about 0.2 to about 0.9:1 and the ratio of R2SiO units to
SiO2 units being up to about 0.1:1 (e.g. MDQ resins);
where each R is an independently selected substituted or
unsubstituted alkyl rad:ical, aryl radical, alkaryl radical,
aralkyl radical, cycloalkyl radical or alkenyl radical;
and thereafter evaporating the solvent.
In an especially preferred embodiment, the water
repellent composition employed in the practice of the
method of the invention is a solution comprising the
aforesaid MQ resin and/or MDQ resin and an alkylalkoxy-
polysiloxane resin.
'De'scr'ip'tion of''the''Inve'nt'i'on
In accordance with the present invention there
is provided a method for rendering masonry water repellent,
comprising contacting the masonry with a solution
comprising an organopolysiloxane resin selected from the
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group consisting of resins containing R3SiOo 5 units and
SiO2 units, the ratio of R3SiOo 5 units to SiO2 units
ranging from about 0.2 to about 0.9:1 and resins containing
R3SiOo 5 units, R2SiO2 units, and SiO2 units, the ratio
of R3SiOo 5 units to SiO2 units ranging from about 0.2
to about 0.9:1 and the ratio of R2SiO units to SiO2 units
being up to about 0.1:1; where each R is an independently
selected substituted or unsubstituted alkyl radical, aryl
radical, alkaryl radical, aralkyl radical, cycloalkyl
radical or alkenyl radical; and thereafter evaporating
the solvent. Preferably, substantially all of the R
groups are methyl.
Method for preparing such organopolysiloxane
resins are well knwon in the art, for example, as described
in U.S. Patent No. 2,398,672, issued April 16, 1946 to Sauer,
U.S. Patent No. 2,676,183, issued April 20, 1954 to Daudt
et al, U.S. Patent No. 2,736,721, issued February 28, 1956
to Dexter, and U.S. Patent No. 2,857,356, issued
October 21, 1958 to Goodwin, Jr. Other method for
2a preparing resins of this type will be apparent to those
of ordinary skill in the art.
Generally, the MQ and MDQ resins employed in
the practice of the invention are provided as a solution
in an organic solvent such as xylene or toluene, and
typically as a 40 to 60 percent by weight solution. It
is, however, desirable to dilute the solution so that it
contains from about 1 to about 20 weight percent resin
solids before applying it to masonry by conventional means
such as, brushing, spraying, and the like. Most preferably,
the solution contains about 10 weight percent resin solids.
It should be understood that the term "masonry"
as used herein includes, but is not limited to, building
and surfacing materials such as brick, concrete, cinder
block, mortar, tile, stone, stucco, sandstone, limestone
and equivalent materials. A particularly preferred aspect
of the present invention involves applying the compositions
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of the present invention to statues and stone monuments
in order to protect them from the adverse affects of
acid rain and other environmental pollutants.
After the organopolysiloxane resin has been
applied to the masonry, the solvent is evaporated by air
drying or exposing the coated masonry to elevated
temperatures, for example, in a forced hot air oven. For
practical reaons, it is usually most convenient to allow
the coated masonry to air dry.
It is believed that the excellent and long-
lasting protection imparted by MQ and MDQ resins is due,
at least in part, to the fact that they penetrate more
deeply into the pores of the masonry than do prior art
water repellent compositions. Thus, the compositions of
the present invention penetrate up to about 1/2 inch below
the masonry surface whereas prior art compositions generally
do not penetrate more than l/16 to 1/8 inch. In addition,
the MQ and MDQ resins employed in the present invention
can be super saturated onto all porous surfaces without
2Q staining and any excess on the surface can be brushed off
because it is a dry powder at 100~ solids.
In an especially preferred embodiment of the
present invention, the water repellent composition
comprises a blend of an MQ resin and/or an MDQ resin
and an al]cylalkoxypolysiloxane resin. Alkylalkoxypoly-
siloxane resins contemplated for use in the present-
invention are described in U.S. Patent No. 2,624,749,
issued January 6, 1953 to Bunnell and U.S. Patent
No. 2,810,704, issued October 22, 1957 to Krantz.
Particularly preferred for use in the present invention
are the methylmethoxypolysiloxane resins of Xrantz
which are available from General Electric Company under
the trademark DF104. Other suitable alkoxy-functional
silicone resins will be obvious to the artisan or their
suitability can be ascertained without undue
experimentation.
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Examples of alkylalkoxypolysiloxane
resins suitable ~or use in the compositions of
this invention are those having the empirical
formula
R Si(O~nO(3-n)
wherein n is a number from 1/3 to 1, (preferably
1/3 to 0.7), R is a monovalent organic radical
such as methyl, having no olefinic unsaturation in
which the free valence is connected to an acyclic
carbon atom to which at least one hydrogen atom is
attached, and in which any atom other than carbon
and hydrogen is a a halogen having an atomic
weight less than 80 that is attached to a carbon
atom other than one connected to said acyclic
carbon atom; and r is a monovalent organic radical
having no olefinic unsaturation in which the free
valence is connected to an aliphatic carbon atom
to which at least one hydrogen atom is attached,
and in which any atom other than carbon and
hydrogen is a halogen having an atomic weight less
than 80.
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Preferably, the MQ resin and/or MDQ resin is
blended with the alkylalkoxypolysiloxane resin in a ratio
of from about 50 to about 90 parts by weight MQ resin
and/or MDQ resin and from about 10 to about 50 parts
by weight alkylalkoxypolysiloxane resin (i.e., from about
1:1 to about 9:1), although ratios outside of this range
are not precluded. Optimal results have been obtained
thus far when there is employed about 70 parts by weight
MQ resin and/or MDQ resin and about 30 parts by weight
methylmethoxypolysiloxane resin (i.e. DFl04 ).
In order to better enable the artisan to
practice the present invention, the following examples
are provided by way of illustration and not by weight of
limitation. All parts and percentages are by weigh~ unless
otherwise noted.
EXAMPLES
Exa'mpl'e' 1
A 60% solids in xylene resin composed of
(CH3)3SiOo 5 units and SiO2 units in a ratio of 0.8:1
was diluted to 10% solids with mineral spirits. The
diluted solution was applied by brushing to Danby Vermont
Marble, concrete test block, and clay fired, redstone
tile. Following air drying for 24 hours the coated
materials all exhibited excellent water repellency.
It was noted that the resin solution completely
penetrated through 3/8 inch thick marble providing for
internal water repellency, not just surface protection
as with many prior art film-forming water repellent
compositions. It was also noted that the resin solution
3~ penetrated about halfway through the 3/8 inch clay fired,
redstone tile.
Example 2
The resin solution prepared in Example 1 was
coated on concrete test block, dried 48 hours, and
weighed before being immersed briefly in water. The
block was patted dry with absorbent paper and reweighed.
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There was an increase in weight of 0.5 gram. The block
was then immersed in water for 48 hours, patted dry with
absorbent paper and reweighed. There was an increase
in weight of 1 gram. Following a 14 day immersion,
there was a 4 gram increase in weight compared to a 19
gram increase in weight on a non-treated block.
Example 3
The treated Danby ~ermont Marble of Example 1
was further tested for stain resistance. Black spray
enamel diluted in toluene and naphtha was stprayed on
the surface and after drying for one hourthe paint was
completely removed with a solvent wipe. On untreated
Danby Vermont Marble, the paint left a permanent black
stain.
Ex'ample 4
A blend containing 50 grams of the MQ resin
of Example 1, 4.3 grams of DF104 resin available
from General Electric Company, and 276 grams of mineral
apirits was mixed by simple shaking in a glass bottle.
The blend was completely compatible in solution and was
clear upon evaporation oE the solvent. A heavy coating
of this blend was applied by brushing to a cement test
block and air dried for 24 hours. The block was then
immersed in water for three days. The block was blotted
dry and tested for water repellency with drops of water
placed on the surface. The drops flattened showing a low
contact angle.
Example 5
A blend of 50 grams of the MQ resin of Example 1,
8.6 grams DF104 M resin, and 301 grams of mineral spirits
was prepared and tested as in Example 4. Drops of water
placed on the cement block were not as flat as in Example
4, but there was not a sharp contact angle.
Example~ 6
A blend containing 50 grams of the MQ resin
of Example 1, 12.9 grams of DF104 resin, and 327 grams
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of mineral spirits was prepared and tested as in Example
4. Drops of water placed on the cement block showed a
very sharp contact angle and stayed in a sphere.
Example 7
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A blend containing 50 grams o the MQ resin of
Example 1, 17.2 grams of DF104 M resin, and 355 grams of
mineral spirits was prepared and tested as in Example 4.
The contact angle of drops of water on the cement surface
was not as spherical as in Example 6
