CA1069257A - Method for rendering non-porous surfaces water repellent - Google Patents

Method for rendering non-porous surfaces water repellent

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Publication number
CA1069257A
CA1069257A CA312,915A CA312915A CA1069257A CA 1069257 A CA1069257 A CA 1069257A CA 312915 A CA312915 A CA 312915A CA 1069257 A CA1069257 A CA 1069257A
Authority
CA
Canada
Prior art keywords
vol
composition
polysiloxane
isopropyl alcohol
sulfuric acid
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
CA312,915A
Other languages
French (fr)
Inventor
James D. Savage
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to CA312,915A priority Critical patent/CA1069257A/en
Application granted granted Critical
Publication of CA1069257A publication Critical patent/CA1069257A/en
Expired legal-status Critical Current

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Classifications

    • CCHEMISTRY; METALLURGY
    • C09DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09KMATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K3/00Materials not provided for elsewhere
    • C09K3/18Materials not provided for elsewhere for application to surfaces to minimize adherence of ice, mist or water thereto; Thawing or antifreeze materials for application to surfaces

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Materials Applied To Surfaces To Minimize Adherence Of Mist Or Water (AREA)
  • Paints Or Removers (AREA)

Abstract

A B S T R A C T O F T H E D I S C L O S U R E
This invention comprises a method and composition for treating non-porous surfaces to render them water repellent. The composition consists of a mixture of mineral acid and a solvent to which a polysiloxane of general formula:

Description

~ 9Z57 This invention as described relates to the application of a material mixture to non-porous surfaces such as glass, plastic, vinyl and nickel alloy in such a manner that the surface becomes water repellent and impervious to the sticking action of insects, road salt and general air pollution contaminants which are present in the atmosphere and which tend to form opaque films on the described surfaces. Such an invention, when properly applied, possesses safety features so that the accumulation of road slush and salt on automobile windows and the deposition of frost and liquid haze on safety goggles, glasses or protective helmet screens are minimized. In addition, the product is of economic importance. The application of the composition to building windows will prevent the accumulation of grime on these surfaces and consequently the number of cleanings per year will be reduced.
Previous patents (Canada, 820761) described procedures whereby surfaces are treated with substituted polysilanes. These compounds have the general formula:

-- si -- si I
which is substituted with methyl, ethyl, propyl, butyl and amyl groups in a range from 16 yo 20 carbon atoms. It was also established that compositions containing polysilanes should have no ethyl groups since they contribute little to the adhesion or repellent properties of the mixture. It was also shown that polysilanes containing two methyl groups were a compromise since the monomethyl derivative gave less adhesive properties whereas the trimethyl derivative yielded less repellence than desired.
It is known tbat a repellent applied to non-porous surfaces should have strong adhesive properties, minimum accumulation and repel the adverse condition such as water or frost. Repellents composed of polysilanes, in general, lack uniform adhesive properties and must be composed to include an adhesion promoting factor. The use of such adheslon promoting agents, such as finely divided carbon black or a , ~L~6~ZS7 mixture of carbon black and rouge does increase the adhesion properties of polysilanes but the abrasive properties of these agents may have a deleterious effect on the applied surface.
The disadvantage exhibited by polysilanes in that the adhesive properties of the composition must be augmented by an additional formula-tion maybe overcome due to the recent commercial availability of polysiloxanes. These compounds differ from polysilanes because the silicon atoms are linked through atoms of oxygen. The generalized formula of a polysiloxane is given below:

Rl E~
R2 n where n is an integer greater than one, Rl is an alkyl group consisting of one to seven carbon atoms and R2 may be hydrogen, a lower alkyl or an aryl group. It is believed that the silicon-oxygen bond increases the adhesive properties, especially to glass, because it more closely resembles the structure of the coated surface.
Polysiloxanes are commercially available and n varies between 5 and 900 and the molecular weight of the preferred derivative, dimethyl-polysiloxane ranges from 400 to 60,000. The rationale that dimethyl polysiloxane is the derivative of choice, i.e., Rl and R2 are methyl groups arises from the same rationale developed for the polysilane derivatives in that a compromise between the adhesive and repellent properties must be achieved. In the formulation of a repellent it was determined that the expensive polysiloxane may be employed in the presence of an extender, or solvent, thereby decreasing the cost of the composi-tion and presenting it in a readily applied formula. Many solvents or extenders are available for use with polysiloxanes, however, those such as ethers, ketones, benzene, carbon tetrachloride, toluene or xylene etc.
are either corrosive or toxic to the human element. It has been deter-mined that a simple, readily available solvent, isopropyl alcohoI, is .:

-suitable for use as an extender if properly treated to prevent formation of a biphasic mixture when mixed with po:Lysiloxane derivative. Isopropyl alcohol is treated with sulfuric acid wh:ich catalyzes the formation of an intermediate half-ester in which the polysiloxanes are soluble. The use of a relatively volatile solvent such as isopropyl alcohol ensures the application of a uniform polysiloxane film which dries in a short time. The concentration of acid used to solubilize the polysiloxane is not corrosive or hazardous since it is employed only in catalytic quantities. The steps involved in the preparation will be outlined in further detail.
PREPARATION l.
Sulfuric acid was added to isopropyl alcohol to a final concen-tration of 1% (vol/vol) to form the intermediate half-ester. To this solvent was added dimethyl polysiloxane (visiosity 5 to 20 cps) to yield a 10% solution (vol/vol). The composition was stirred for some time to effect solution. The composition was applied with the aid of a clean, soft cloth to a previously cleaned and dry automobile windshield.
The solution was allowed to dry for a few minutes and any excess was removed with another dry cloth or paper towel. During a two to four week period, of moderate temperatures, the effects of the solution on the windshield were observed. It was noted that water, in the form of rain, did not adhere to the windshield when the automobile was moving at average velocities, i.e. 25 mph or greater. The repellent action of the composition when the vehicle was stopped, although not absolute, was still present. Xt was also observed over this time period that the accumulation of insect bodies and road grime on the windshield was minimal. The composition was also tested on an automobile windshield under adverse condi1:ions of late winter and early spring. It was deter-mined that the properties listed above were still prevalent, however, the film appeared to become ineffective in approximately one week. An additional composition, described below, was prepared and tested under these conditions.

- -~69Z57 PREPARATION 2.
The results of the tests described under Preparation 1 indicatedthat the adhesion properties of the composition in general and the dimethyl polysiloxane in particular were altered in a deleterious manner when subjected to such adverse conditions as low temperature, road salt and sand and snow slush. Based upon this premise and additional composition was formulated based upon that described in Preparation 1.
To the composition described in Preparation 1 was added 1~ methyl phenyl polysiloxane (vol/vol). It was deduced that under severe condi-tions of cold and ice, a more "fluid" composition should possess greater adhesion properties. These properties would result from the addition of the phenyl ring structure since it is known that these derivatives may contribute to an increased "elasticity" and a decreased "brittleness"
of the applied film. This property exhibited at lower temperatures, is due to the presence of a greater degree of unsaturated carbon-carbon linkages within the phenyl group as compared to the saturated methyl derivative. The application of this preparation was performed as described for Preparation 1 and tested on an automobile windshield under adverse conditions of climate. It was observed that in the presence of road salt and slush, at below freezing temperatures, the film adhered to the windshield and was still an effective repellent for approximately three weeks. Thus, the addition of methyl phenyl polysiloxane to preparation 1 increased the effectiveness of this product under adverse conditions so that it was at least as effective as the initial preparation under more moderate conditions. It was also observed that each composition yielded a completely transparent film on the windshield and no evidence for buildup was noted. It is stated that these results were obtained without the aid of auxillary windshield clearing equipment such as wiper blades.
Compositlon 1 and composition 2 have been tested and observed under additional conditions. Composition 1 was applied to the ceramic tiles of a ba~th-tub and shower enclosure and it was observed that water was not accumulated on these surfaces. The accumulation of water scale -:

1~6925~

was almost entirely eliminated. The compositions have been tested on safety goggles and transparent face masks of motorcycle helmets. Similar results to those observed on automobile windshields were obtained. The compositions may also be applied to skiis to increase the velocity of downhill runs and to prevent the accumulation of snow and ice on the upper surfaces.
It is understood that variations maybe made from the preferred embodiment of this invention as described herein such that the spirit and scope of the invention as defined in the appended claims are maintained.

Claims (3)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:
1. A composition of matter for rendering non-porous surfaces water repellent consisting of one or more polysiloxane of structure:

where n is an integer greater than 1, R1 is an alkyl group containing from 1 to 7 carbon atoms and R2 is a hydrogen, alkyl or aryl group, sulfuric acid, and isopropyl alcohol, said isopropyl alcohol being present in concentration of 80 to 90% (vol/vol) and being suitable for application of the composition of matter and the sulfuric acid being present in concentration of about 1% suitable to catalyze the formation of an intermediate half ester of isopropyl alcohol, so that the polysiloxanes are soluble for application.
2. A composition according to claim 1 consisting of 10%
dimethyl polysiloxane, 1% sulfuric acid and 89% isopropyl alcohol (vol/vol).
3. A composition according to claim 1 consisting of 10%
dimethyl polysiloxane, 1% sulfuric acid, 0.1% to 10% methyl phenyl polysiloxane and 88.0 to 88.9% isopropyl alcohol (vol/
vol).
CA312,915A 1978-10-05 1978-10-05 Method for rendering non-porous surfaces water repellent Expired CA1069257A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CA312,915A CA1069257A (en) 1978-10-05 1978-10-05 Method for rendering non-porous surfaces water repellent

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CA312,915A CA1069257A (en) 1978-10-05 1978-10-05 Method for rendering non-porous surfaces water repellent

Publications (1)

Publication Number Publication Date
CA1069257A true CA1069257A (en) 1980-01-08

Family

ID=4112563

Family Applications (1)

Application Number Title Priority Date Filing Date
CA312,915A Expired CA1069257A (en) 1978-10-05 1978-10-05 Method for rendering non-porous surfaces water repellent

Country Status (1)

Country Link
CA (1) CA1069257A (en)

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