CA2017090A1

CA2017090A1 - Coating composition

Info

Publication number: CA2017090A1
Application number: CA 2017090
Authority: CA
Inventors: Stephen Dunn
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-05-17
Filing date: 1990-05-17
Publication date: 1991-11-17
Also published as: FR2662171A1; GB2244715B; DE4115857A1; AU651103B2; AU7702691A; GB2244715A; GB9110046D0

Abstract

A B S T R A C T

A composition for coating porous and nonporous materials to render same water repellent with a composition consisting essentially of an alkyl polysiloxane and sodium silicate in an amount about 5% to 150% based on weight or volume of said polysiloxane.

Description

- ~ ~? 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.
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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.

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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.

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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.

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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.

Claims

1. 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:

n n being an integer greater than 1; R1 a lower alkyl radical containing from 1 to 7 carbon atoms; and R2 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 150% based on weight or volume of said polysiloxane.

2. A composition according to Claim l wherein said composition further contains a polysiloxane emulsifier so that the emulsified polysiloxane contains 30% - 70% silicone to which is added up to 200 parts water per one part of emulsified polysiloxane.

3. A composition according to Claim 1 wherein said composition further contains one part propylene glycol (USP) or glycerine (USP) per 400 parts of emulsified polysiloxane.

4. A composition according to Claim 1 wherein said composition further contains one half part propylene glycol and one half of one part glycerine (USP) per 400 parts emulsified polysiloxane.

5. A composition according to Claim 1 wherein said alkyl polysiloxane is phenylmethyl polysiloxane.

6. A composition according to Claim 1 wherein said alkyl polysiloxane is methylhydrogen polysiloxane.

7. A composition according to Claim 1 wherein n has a value about 4-950.

8. A composition according to Claim 1 wherein said alkyl polysiloxane is polydimethyl siloxane.

10. A composition according to Claim 1 wherein said composition further contains water as a solvent and diluent.