US 2476178 A
Description (OCR text may contain errors)
Patented July 12, 1949 COATING COMPOUND Overt-on J. Cahill, Wooster, Ohio, assignor to Alfred E. Braun, Wooster, Ohio No Drawing. Application August 11, 1944, Serial No. 549,119
1 Claim. 1
This invention relates to an improved coating compound and more particularly to a compound eminently suited for use on prefabricated roofing material and building sidings, although by no means limited to such' use.
Among the objects of the invention are to substantially increase the resistance of such a compound to wear and weather and to not only improve the appearance of the applied coating at the time of application but so compound the same that it retains its attractive and functionally useful surface texture and appearance throughout its resultant extended life.
Coatings of the type with which I particularly concern myself here are of an extremely viscous nature and are intended for application in such manner as to form a relatively thick coating. The generally mastic nature of the proposed compound is indicated to some extent by the fact that its viscosity is such that it cannot be measured by the usual efliux type viscometer. Hitherto coatings of this general type have been peculiarly susceptible to mutilation and deformation by impact when softened by heat, due to the fact that the basic materials of which such compounds are composed are conventionally thermoplastic substances such as tar or pitch, asphalt, and various compounds of such substances in conjunction with drying and semi-drying oils.
By reason of the above, I have found that the useful life of standard coatings utilizing such materials as those suggested above is greatly impaired, deterioration in both appearance and structure in warm weather climes being unduly rapid.
I propose to attain the objectives outlined above and at the same time rigidify and harden a coating compound of this general nature to such an extent that its thermoplastic or pliant characteristics at elevated temperatures are greatly reduced. This I propose to accomplish by thoroughly interspersing non-oxidizing or slowly oxidizing metallic particles or powders throughout a body of mastic compound to form a metal-bearing, hea y, viscous coating. I have found that aluminum particles or flakes are particularly suited to accomplish the desired ends, although various other metallic flakes such as copper and bronzes, commonly known as bronzing powders, are capable of obtaining desirable results to a lesser extent.
The use of metallic flakes in prefabricated roofing elements and in paint is not novel. Hitherto aluminum flakes have been utilized in conjunction with composition roofing material to form a protective surface lamination. In such cases the characteristic inherent in aluminum particles of flattening or more or less leveling out parallel to the surface to which they are applied has been utilized, both for surfacing composition roofing materials by spraying or otherwise, and for paint, solely for the purpose of forming a light-reflecting non-oxidizing surface lamination adapted. to protect the underlying composition material. The tendency of aluminum flakes to leaf out and overlap obtains a more or less continuous shingled surface lamination completely covering the underlying composition'material. These various advantages have been pointed out in the prior art.
My improved coating derives all the advantages hitherto brought out insofar as the formation of a surface-protective coating is concerned and, at the same time, produces a coating having a cellular or honeycomb structure throughout the entire body of the applied coating.
Various important advantages are derived from this cellular structure in addition to the strengthening and rigidifying of the body of the coating due to the interlocking action of the flakes. It should be borne in mind that, quite in contradistinction to applying a surface coating or even interspersing suflicient metallic particles within the prepared mastic to level oil on the surface to form an overlapping protective surface, this invention contemplates interspersing in the prepared coating particles in a quantity far in excess of that required to accomplish these ends.
The quantity of metal particles interspersed in the mastic mix is such that the tendency of a major portion thereof to leaf out in a direction parallel to the surface when applied will be blocked by a similar tendency on the part of adjacent particles. This blocking of the normal tendency of the various particles or flakes by various adjacent particles produces an interlocking of metallic flakes forming a honeycomb or cellular structure throughout the body of mastic, the cells being of mastic and the separating walls of what may be described as interlocking metallic flakes.
As a result the coating when applied embodies a substantially continuous metallic surface coating and in addition the cellular structure throughout its body. Wear and deterioration of the initial surface coating will simply expose a second similar surface coating, and a series of successive surface coatings will make their appearance from time to time throughout the life of the coating. Thus the coating throughout its entire life obtains all of the useful and desirable results, such as high reflectivity, resistance to oxidation, and wear resistance obtainable to an extremely limited extent by the surface coatings of the prior art.
In addition to this, however, the cellular structure developed on application of my improved coating aids greatly in dissipating any heat to which it is subjected. Its action in so dissipating the heat is much the same as any honeycomb heat transfer device wherein an excess of metallic surface is available. In the instant coating structure the excess metallic surface formed by the cell Walls and conducting the heat from the surface of the coating is in all instances in contact with the mastic or bituminous substance forming the cells and constituting the vehicle body of the coating, and the heat is to a large extent absorbed by the latter. This function is important for many reasons.
There are certain advantages in reflecting as much light as possible by virtue of the metallic surface, and to some extent heat. Deterioration of the mastic body is to a great extent delayed by protecting the same from light, adverse weather conditions, and the usual oxidizing influences to which coatings of this type are normally subjected. On the other hand, there are numerous disadvantages in reflecting maximum heat from coatings applied to, let us say, tin roofings adjacent windows in dwellings, etc., where the occupants are subjected to the reflected heat. Ihus the cellular structural feature of my improved coating obtains to the fullest extent the advantages of a metallic protective coating, including its reflecting characteristics, for the entire life of the coating while at the same time obtaining important additional advantages by way of heat dissipation which are unobtainable in other com= pounds of this nature. All of the various advantages resulting from this construction remain with the coating until the same is dissipated by reason of the fact that the cellular structure extends throughout the body of the same when applied and continuing wear succeeds only in eliminating one metallic surface layer after another.
As an example of the continued light-reflecting characteristics of my improved compound, it may be stated that a typical coating without the metallic particles interspersed throughout in accordance with my invention was applied to a tin panel, which panel together with an identical panel treated with the coating described herein was weathered in a weatherometer for are hours under conditions equivalent to exposing the same are days on the Florida seacoast. Both panels were then tested for their degree or rating of reflectance in a Hunter reflectometer. The results of this test showed that after exposure to the conditions indicated the panel coated with a normal compound showed a rating of zero whereas the panel coated with my improved compound showed a rating of In other words, after exposure in the manner aforesaid the normal coating possessed no reflectance whatsoever whereas my improved coating still reflected 40 71. of the light thrown upon its surface.
In compounding my coating any of the usual roof coating materials may be used and subsequently interspersed in the manner described with metallic particles in sufficient quantity to accomplish the hitherto described results. Such roof coatings are invariably characterized by their high degree of viscosity, which controls the thickness of the applied coating and the distribution therein of the metallic particles. This basic compound forms a vehicle for the particles and its minimum viscosity should be such that it cannot be measured by use of an eiilux type viscometer. vehicle or basic coating substance capable of interspersion with metallic particles in the man- I have successfully compounded nor described herein from one or a combination of the following basic raw materials: tar or pitch, asphalt, gilsonite, elaterite, vegetable pitch, tall oil, China wood oil, fish oil, linseed oil, soybean oil, castor oil, oiticica oil, rosin oil, perilla oil, petroleum oil, petroleum solvents, earth fillers, organic pigments, and inorganic pigments, I have, however, found extremely satisfactory results to obtain from use of the following compound, which is given by way of example only and not in any way as a limitation:
To parts by volume of a mixture comprising in equal parts an asphalt varnish embodying melting point asphalt and including '71 parts solid material and an asphalt-gilsonite varnish embodying 56' parts solid material is added 3 parts or blown soybean oil or kettle-bodied, blown linseed oil. To this is added 3 parts of a kettletreated, dehydrated castor oil of heavy viscosity, after which to 750 parts, by weight, of the resulting mixture is added 25 parts, by weight, of long asbestos fiber, 25 parts, by weight, of short asbestos fiber, and 3 parts, by weight, of fine carbon black.
To the bulk of this resulting vehicle metallic flakes are added in a quantity sufficient to form therewith when applied as a coating a complete interspersion of interlocking particles through-- out the coating. As hitherto suggested, aluminum flakes are preferable and for the batch of mastic described above I have found that per gal. 14% lbs. of metallic particles are sufficient.
I prefer to use medium size aluminum flakes rather than the fine grade not only because the size thereof lends itself more advantageously to accomplishing the desired ends, but because they remain in suspension in the coating compound prior to application of the coating more readily than the finer particles. The mixing of the asbestos fibers and the metallic particles into the base vehicle may be accomplished in any suitabls container equipped with agitating means whereby these materials may be thoroughly incorporated throughout the vehicle.
Having described a preferred embodiment my invention, various modified forms may be-- come apparent to those skilled in the art and for that reason I wish to be limited only by the appended claim.
What I claim is:
A coating compound consisting of a mechanical mix comprising 100 parts mixture of asphalt varnish and asphalt gilsonite varnish, approximately 6 parts of oil of the class consisting of drying and semi-drying oils, and 50 parts of asbestos fiber, said mix having incorporated and interspersed thoroughly throughout metallic flakes in the proportion of from 1 to 1 /2 lbs. per gal. of mix.
OVERTON J. CAI-IILL.
REFERENCES CITED The following referenlces are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 1,568,215 Fleming Jan. 25, 1926 1,992,695 Ford Feb. 26, 1935 2,201,981 Baron May 28, 1940 2,255,825 Skeen Sept. 16, 1941 2,332,219 Harshbcrger 1- Oct. 19, 1943