Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
- ~ ~? l ;l ~ ~
This invention relates to a method for treating the surface
of porous materials such as leather, canvas, fabrics, etc., and
nonporous materials such as glass, plastics, metal, ceramics,
etc., to make them repel water, to reduce the build-up of grime
and dirt, to reduce the bonding of frost and ice and to inhibit
the occurrence of rust.
Water can cause great damage to a wide range of materials.
It can reduce effective life, performance and appearance. Water
can cause impaired vision, staining, soiling, corrosion and
rusting, and can change electrical properties.
The water repellent products that are currently available
have many disadvantages. They are often flammable, toxic or
corrosive, and often contain acids such as sulphuric or
hydrochloric. They are thus dangerous in preparation,
transportation, in use.
The present invention provides a nonflammable water
repellant product that is noncorrosive, nonabrasive, and nontoxic
and does not contain acids or chlorides.
Currently available rain repellent products can be applied
to only a few materials, and often they require extensive
preparation of the surface to be treated, and special application
methods. Current water repellent compositions often lack long
life and durability and they often streak and smear.
Compositions containing acids should not be used on aircraft or
automobile windshields because of the rubber or other materials
used in mounting the windscreens.
It is, therefore, an object of the present invention to
provide a novel water repellent composition which can be applied
to a wide number of materials, both porous and nonporous, to make
them water repellent.
Another objective of this invention is to make an improved
water repellent composition which is nonflammable, nontoxic,
noncorrosive, nonabrasive, free from acids and chlorides and
which will not damage paint, dopes, fabrics, metals, glass,
rubber, plastics, ceramics, and so on.
A further objective of the present invention is to make a
water repellent composition that is very economical, easy to
apply to surfaces of any shape, long-lasting, and durable.
A further object of the present invention is to provide a
prcduct that does not materially alter the refractive index of
glass or plastic transparencies and is able to resist W
deterioration.
20Still another object of the invention is to provide a
composition that will not lose its effectiveness if it is subject
to alcohol, de-icing fluids, gasoline, antifreeze, glycols, heat,
or cold.
In a broad aspect, the present invention relates to a
composition for coating porous and nonporous materials to render
same water repellent with a composition consisting essentially
of an alkyl polysiloxane having the formula:
o ' sio
Wherein n being an integer greater than 1, R, a lower alkyl
radical containing from 1 to 7 carbon atoms, and Ra hydrogen, a
lower alkyl radical containing from 1 to 7 carbon atoms, or an
aryl radical containing about 6 carbon atoms; and sodium silicate
in an amount about 5% to 85% based on weight or volume of said
polysiloxane.
Polysiloxanes alone have virtually no ability to adhere and
to be a durable water repellent product and it is necessary to
add an agent so as to have the composition adhere to a surface
and to make the surface water repellent. The addition of sodium
silicate as described herein accomplishes this.
Not all polysiloxanes are effective. Examples of suitable
polysiloxanes are phenylmethylpolysiloxane, polydimethylsiloxane,
methylhydrogen polysiloxane. They are available from Dow
Corning.
The amount of sodium silicate relative to the above
polysiloxanes has a wide range of effectiveness. Ratios from 5%
- 150% sodium silicate by weight or volume, with a preferred
range of 40% - 60% sodium silicate to polysiloxane are within the
effective ranges of the present invention.
The active ingredients, polysiloxane and sodium silicate,
can be used in solution alone but other compounds can be
advantageously added.
Moreover, the composition is still effective in diluted
form. Dilution is accomplished by adding an emulsifier to a
suitable polysiloxane, so that there is a silicone content of 30%
- 70%, and then adding water to make the desired composition.
Dilutions of up to two hundred (200) parts water to one (1) part
polysiloxane emulsion are possible.
It is a very important part of this invention that the
relatively expensive polysiloxane can be emulsified and then
diluted with water without loss of effectiveness. As only a very
thin film of the composition should be applied to the material
dilution is desired from a technical consideration as well as an
economic consideration.
:.
The amount of dilution that is possible has a wide range.
The applicant has successfully tested two hundred parts water to
one part emulsified polysiloxane but the preferred amount is
forty to sixty (40-60) parts water to one (1) part emulsified
polysiloxane.
The composition has been successfully tested over the
following ranges:
* 400 parts of emulsified polydimethylsiloxane (30% - 70%
silicone or emulsified phenylmethylpolysiloxane (30% -
70% silicone)
* 400 - 80,000 parts water
* 40 - 600 parts sodium silicate.
The preferred composition is:
* 400 parts of emulsified polydimethylsiloxane (55% - 65%
silicone) or emulsified phenylmethylpolysiloxane)
* 18,000 - 22,000 parts water
* 180 - 220 parts sodium silicate.
, .
Preparation of the composition is easy and safe. The
emulsified polysiloxane and water are thoroughly mixed and then
the sodium silicate is added and thoroughly mixed. The materials
are mixed at normal room temperature.
:
Examples of suitable formulations follow:
Example 1
1 litre of a suitable polysiloxane was mixed with one-half
litre of sodium silicate and 40 litres of water.
Example 2
1 litre of a suitable polysiloxane was mixed with one litre
of sodium silicate and 60 litres of water.
Example 3
1 litre of a suitable polysiloxane was mixed with one-fifth
litre of sodium silicate and one hundred litres of water.
Example 4
1 litre of a suitable polysiloxane was mixed with one-half
litre of sodium silicate and five litres of water. lml of
- glycerine (USP) was then added.
Example 5
1 litre of a suitable polysiloxane was mixed with one-half
litre of sodium silicate and eighty litres of water. lml of
propylene glycol was then added.
-' , '
Example 6
1 litre of a suitable polysiloxane was mixed with three-
quarters litre of sodium silicate and one-hundred and twenty
litres of water. lml of glycerine (USP) was then added.
~X3~D19_~
1 litre of a suitable polysiloxane was mixed with one-half
litre of sodium silicate and 10 litres of water.
Example 8
1 litre of a suitable polysiloxane was used with 1~ litres
of sodium silicate and 50 litres of water.
In each of the foregoing examples, the polysiloxane utilized
was Dow Corning 346 Silicone Emulsion. The sodium starting
silicate solution in each case was an aqueous solution containing
37.6% sodium silicate.
In certain uses it could be desirable to include additional
polishing compounds. Adding one (1) part propylene glycol (USP)
or one (1) part glycerine (USP) to the above preferred
composition adds to polishing characteristics. As a variation
of the foregoing one half (%) part propylen~e glycol (USP) plus
one half (~) part glycerine (USP) may be adqed. Care must be
taken not to add these additional polishing ing~eqte~ts in exce~
of the foregoing as this could cause a smearing effect in
application.
The composition should be stored at above freezing
temperatures. However, if it freezes it may be thawed at room
temperature and there will be no loss of effectiveness.
To apply, one first cleans and dries the surface to be
treated. A clean dry cloth is moistened with the composition,
which is applied lightly over the entire surface. It is allowed
to partially air dry and then buffed. Only a thin film is
required. The composition can also be easily applied by brush
or spray.
A number of tests, for a wide range of purposes, with the
composition has been done. One of the most important uses is to
repel rain from windscreens on aircraft, motor vehicles such as
automobiles, trucks, boats. All of the glass on the driver's
side of an automobile was treated and then driven in moderate to
cloudburst rain conditions. The rain on the treated glass formed
into innumerable tiny beads that did not coalesce. These tiny
beads were blown off the qlass as the speed approached 30 - 40
m.p.h., and the visibility was excellent without the use of the
windshield wipers. The untreated glass had the typical water
sheeting and impaired to zero visibility. Subsequently, all the
glass on two cars was treated and after six months during which
time the cars had been washed approximately twice weekly in
2l ~Jv~J ~
typical service station mechanical car washes, windshield wipers
were still not required.
Another important feature of the present invention is that
- it inhibits the bonding of frost and ice to the treated surface.
This is not to say that it prevents frost and ice from forming
on the treated surface, but that it makes it much easier to
remove. Several different types of glass, each about one foot
square, were coated with the composition and then sprayed with
water. They were then placed in a deep freeze for several hours
so the water would freeze. When the treated glass was removed
from the freezer there were hundreds of tiny frozen beads on the
surface which were removed with gentle scraping. The
freezing/scraping tests were repeated 47 times without loss of
efficiency.
Moreover, the composition of the present invention is useful
in coating aircraft wings to render de-icing more efficient.
Also, the composition of the present invention may be used to
coat boats and water craft to inhibit ice and dirt build-up. The
composition may also be used as a treatment for snow skis, to
decrease their friction against snow.
The removal of insect splatter on a windshield that has been
treated with the composition is facilitated.
..
The composition can be applied to leather goods such as
shoes, coats, belts, etc., to make them water repellent. In
addition to the water repellency the leather, especially shoes,
takes on a lustre and shine.
The composition was applied to a new steel chisel, a new
saw, a new pair of pliers and an iron bar. They were left
outside on moist dirt and exposed to the elements. After eight
months there was no sign of rust.
The composition was applied to one half of a silver wine
cooler. After several weeks there was only a small amount of
tarnish on the treated surface whereas the untreated surface had
the usual unattractive tarnish build-up.
The composition was applied to a two gallon brass pail and
the tarnish build-up has been greatly reduced.
The composition was applied to the plastic water container
for a household humidifier system. It has inhibited scaling from
the minerals in the water from adhering to the treated surface.
It is thus much easier to clean the humidifier water pan.
The composition was sprayed on the leaves of indoor tropical
plants found in homes and offices. The leaves took a very
pleasant shine than enhances their appearance. After eight
months (at the time of writing) the plants have not shown any
deleterious effect and in fact have prospered.
It is to be understood that the examples described above are
not meant to limit the scope of the present invention. It is
expected that numerous variants will be obvious to the person
skilled in the coating composition formulation art, without any
departure from the spirit of the present invention. The appended
claims, properly construed, form the only limitation upon the
scope of the present invention.
11
