US1753721A - Metal-protected roofing element and method of making the same - Google Patents

Description

April 8, 1930. T. ROBINSON 1,753,721

METAL PROTECTED ROOFING ELEMENT AND METHOD OF MAKING THE SAME Original Filed Feb. 10, 1925 I Ma -5,. 5: 5!

lNV OR ATTORNEYS Patented Apr. .8, 1930 UNITED STATES PATENT OFFICE THOMAS ROBINSON, OF NEW YORK, N. Y., ASSIGNOR TO ANACONDA SALES COMPANY, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE METAL-PROTECTED ROOFING ELEMENT AND METHOD OF MAKING THE SAME Original application filed February 10,1923, Serial No. 618,246. Divided and this application filed May 15,

' 1926. Serial No. 109,425.

This invention relates to roofing elements which may be made in the form of single and multiple unit shingles, tiles, boards, strips, and the like. More specifically, the invention relates to a novel roofing element, and a method by which it may be made, the element, in some respects, resembling the so-called prepared roofings now in wide use but affording important advantages thereover, due primarily to the provision of a metallic coating over that surface of the element which is to be exposed to the weather.

Roofing elements of prepared roofing, such as asphalted felt, asbestos products and the like, are satisfactory for many purposes and are much cheaper than wooden shingles. They have certain objectionable features, however, as for example, their thinness, re-' 'sulting in a lack of rigidity and weight which to some extent reduces their marketability. Also, these products are frequently impregnated with compounds which'include volatile oils, and after exposure, these oils are lost, and rotting or other deterioration of the base materials results. This frequently leads to warping or curling of the exposed edges of the elements, and, aside from the unsightly appearance of the roof that follows, leakage may occur. Such prepared roofings are much more fire-resistant than wood shingles and are consequently required in some communities by municipal ordinance, but roofs constructed of them arenot usually attractive in appearance due to the monotonous uniformity in size and color of the individual elements.

The roofing element of the present invention overcomes the disadvantages of the ordinary prepared roofing and it involves the use of a base of a standard type over which is applied athin layer of metal, preferably of a relatively non-corrodible 'kind such as copper. This metal layer may be applied over the entire surface of the base or it, may be limited to that surface of the base which is exposed to the weather. In either case, the base is protected from the elements, deterioration is prevented, the ability of the roof to withstand fire is increased, and the appearance of the roof is made more attractive.-

The application of metal to bases such as I contemplate using is best carried on electrolytically, but when metal is plated on a nonconductive material, 'difliculties are encountered in securing agood bond between the plated layer and the base. The bond between base and metal becomes of great importance where the plated article is to be exposed to variations in temperature because the metal layer has a coefficient of expansion different from that of the base, and temperature changes resulting in expansion and contraction soon cause a separation of the plating from the base. The quality of the bond is much improved when the base employed has an irregular surface for the metal layer when applied electrolytically will enter the interstices or depressions in the base and a mechanical interlock is thus secured.

The ordinary prepared shingle of commerce consists of a felt base suitably impregnated and coated and having a weather surface formed of a layer of granular material such as crushed slate. Such a base Would appear to be satisfactory for plating purposes to produce a composite roofing material, but as the surface is non-conductive, it must first be treated with a conducting substance prior,

to the electrodeposition and it has been found that it is extremely difficult to secure a continuous conductive coating which will extend over all the projecting granules and enter into the depressions between them. When graphite, the conducting substance ordinarily employed in electrodeposition on non-metallic surfaces, is used, not only is it diflicult to secure a continuous coating but the graphite, unless applied with great care, will fill the depressions in the granular layer, thus preventing the interlocking of base and metal. Furthermore, graphite has well-known lubricating qualities which appear to contribute to the separation of base and metal when the product is exposed to the weather.

The element of the present invention is one in which the above difficulties are overcome. and it consists of a base of any desiredtype, which is impregnated or otherwise made waterproof in any convenient way. The base which I prefer to use is made of standard roofing felt, which is a fabric product wellknown in the industry. This base is made waterproof by saturation with asphalt,-and then receives a layer of granular material which gives the base the desired irregular surface and is also electroconductive. The granular materialwhich I employ to provide the irregular surface by which the superior bond between base and metal is afforded, consists of granules of a material such as crushed petroleum coke, calcined coal, and otherlike materials. This granular material is preferably crushed to substantially the same size as the granular materials now commonly used to provide the Wear surface, and in the crushing operation there will be produced particles of various sizes running from fairly coarse toparticles which are quite fine. This granular material is applied to the sur- "face of the asphalt coating and thereafter, when'the coating has set, the'product is plated electrolytically in the usual manner. Nu- 'merous advantages arise from ,the use of a conductive material, which also provides the irregular surface, since the use of another' conducting coating. is thereb dispensed with, and furthermore, a better ond is produced than in the case of a plating over a granular layer which has been rendered con-. ductive by the use of a material such as graphite.

While the conductive granular material may be applied to the surface of the felt web invarious ways, important advantages are obtained byusing as, an adhesive a material which is of a plastic character and has a high.,

coeflicient of expansion. A layer or coating of this material is applied to the surface of the felt in heated condition, and the granular material is then distributed over the coatin and partially embedded therein. The granu es are deposited in suflicient quantities so that adjacent granules are in contact and after the granular material is thus aflixed to the base, the product is set aside and allowed to cool. In cooling, the coating layer con tracts and forces the granular particles into contact with considerable pressure, and this adds greatly to the conductivity of the granular layer and thus facilitates the electrodeposition of the metal.

Such an adhesive coating must be one which is not injuriously affected by the electrolyte and should also be unaffected by the weather. I have discovered that asphalt selected to have a meltin point above the solar heat to which the roo ng is to be exposed is satisfactory for the purpose and when the granular material is embedded in an asphaltic coating and the latter allowed to cool, the granular layer is of greatly increased conductivity and may readily be employed as the cathode in the plating cell.

For a better understanding of the invention, reference will be made to the accompanying drawing, in which Fig. 1 is a face view of a finished element with parts of the different layers on the base broken away for purposes of illustration,

" Fig. 2 is a vertical sectional view through such a product, and

Fig. 3 is an enlarged sectional View similar to Fig. 2, but showing more clearly the'manner in which the metal adheres to the base.

' In the process of manufacturing the new element, the felt used is passed through impregnating vats, where it is saturated with asphalt or a similar waterproofing compound, and is then led through suitable mechanism for applying a coating of an asphalt of a somewhat higher melting point. While this asphaltic coating is still soft and tacky, the felt is led through a distributing device, by which a layer of conductive granular material is applied over the surface of the coating. I have secured the best results with crushed petroleum coke or calcined coal, this material being crushed to approximately the same general size as the crushed slate now commonly used in roofing manufacture. In the crushing operation the material is broken up into granules of different sizes, but it is desirabl'e that the granular material should include particles of various sizes, since in the distribution thereof over the surface of the felt, a more nearly continuous coating is pro yided when the particles vary in size. This follows from the tendency of the fine particles to fill the interstices between the larger particles. w

Passing from the distributing mechanism, the granular material is partially embedded in the surface of the asphaltic coating by roll ressure, or other appropriate means, and the felt is then ordinarily cut into roofing units of the desired shape and size. It is convenient tocut the felt into strip shingles of a type commonly used in commerce, these shingles having a length, in one instance, of approximately 36 inches, and a width of 10 inches, the edge of the shingle which is to be exposed to the weather when the shingles are laid in overlapping courses in the usual manner, being provided with cutouts so that the strip has the appearance of a plurality of single shingle units laid side by si e in the customary spaced relation.

The unitscut from the felt are now allowed to stand until the felt has been restored to room temperature and in thecooling, the asphaltic coating in which the granules are embedded contracts and hardens, gripping the granules securely and forcing adjacent granules into firm contact. The units after such cooling are now introduced into the electrolytic cell, and the plating action takes place. For numerous reasons I refer to employ a plating of "copper on the ases, as this metal has an attractive appearance, is resistant to corrosion, and weathers with color effects which are highly attractive. Other metals, however, may be used if desired. The bases are preferably moved through the cells by suitable conveyors, and the surface on which the plating is to take place is connected electrically as the cathode in the cell. The plating continues until a layer of metal of the desired thickness has been built up.

As illustrated in the drawing, the completed shingle consists of a felt base 5 of proper shape and size, which is impregnated with a waterproofing compound, such as asphalt. Over the surface of this base is the coating 6 of higher melting point asphalt, in the surface of which is embedded the granular material 7, on which a deposit of metal 8 is made. As shown more clearly in Fig. 3, the granular material consists of large particles, such as 9, with the particles 10 and 11 of smaller size between them. In the distribution of the granular material over the surface of the base, this arrangement of particles occurs naturally, the fine particles 10 and 11 lying in the interstices or depressions between the larger particles and being partially submerged in the asphaltic coating under the action of the rolls. Fig. 3 illustrates the arrangement of the different particles on a somewhat magnified scale, but it is apparent that between adjacent particles there are depressions or interstices, such that the entire surface has an irregular contour. The metal coating 8 closely follows the contour of the surface, and consequently has crests and depressions which correspond in a general way to the crests and depressions resulting from the presence of the granules. The metal is of substantially uniform thickness throughout and thus the appearance of the metal layer on the finished product will depend to a large extent on the contour of the irregular granular surface over which the metal is deposited.

Since the grit particles are conductive, the use of a conductive coating such as would be necessary in electroplating metal over a product coated with crushed slate, for example, is avoided, and furthermore, the metal will conform directly to the contour of the particles. When a conductive coatingis required over the granular layer it is diflicult to apply the coating in such a way as to completely cover the projecting portions of the granules .so as to make a conductive surface, and also it is difficult to apply the conductive material in. such a way that it does not accumulate in the depressions between. adjacent particles. \Vhen such accumulation occurs, it is evident that while the surface produced by the granules is irregular, that resulting from coating these granules with a conductive material is much less irregular, and to that extent the bond between the base and the metal is diminished. In the present typle of element the metal is plated directly on t e granules conforming to all of the minute irregularities of these granules and thus being bound firmly to the base.

A further desirable result following from the use of a conductive granular material, re-

sides in the fact that the metal will plate on granules 13 and the granule 14, filling up thisspace so that no metal can enter it. In the present instance, since the usenof graphite or other similar material is avoided, and since the granules are conductive, it is evident that metal will be plated on the underlying surface 12, and thus there is a tongue of metal at this point which is closely interlocked with the base. This same interlocking between base and metal occurs at many points over the surface of the base, and thus the metal layer is firmly bound to the base at many points.

A further desirable result of plating the metal over an irregular surface, is that in addition to the increased strength of the bond, owing to the mechanical interlock between metal and base, expansion difficulties are, to a large extent, obviated, because the metal does not lie in a single plane, as would be the case if the base were relatively smooth. The metal has portions which extend in many directions, and when such a plating of metal is subjected to a temperature which would cause its expansion, the parts of the metal coating which extend in different directions expand in difiierent planes. Thus the expan sion of the metal at one part of the'base will counteract the expansion in apart nearby,

and there is no cumulative effect which has heretofore caused such serious diificulties 1n the separation of the base from the metal in connection with smooth surfaced bases.

In the article as illustrated in Fig. 1, the metal is applied over theentire surface of the base, but this is not necessary in order to produce elements which, when applied on the roof, will provide the latter with a metal coated surface. This is because the elements, 7 I

the metal is applied only to the portions of 1 the elements which are exposed when the elements are laid. For this purpose, the bases are mounted in appropriate shields which mask such parts of the base from the electrolyte as are not to receive a plating and the metal is accordingly lated over only such parts of the base sur ace as are in contact with the electrolyte. The deposition of the metal is carried on by ordinary process and the metal layer is builtup to the desired thickness. Ordinarily a metal coating of from .003 to .012" will be satisfactory. If desired, the metal may be extended around the edges of the element, so as to protect these edges, by an application of a conductive material thereon after the elements have been cut from the main felt web. Graphite or other similar compounds may be employed to produce a conducting coating over the edges.

It will be observed that the new element is cheaper than an ordinary metal-plated grit surfaced roofing because of the fact that no conductive material is employed, and thus a considerable saving is effected at this point, as well as in the labor necessary to apply the conductive coating. Furthermore, the new product is one in which there is a much superior bond between base and metal because of the direct contact and adherence of the metal to thegranules. Where there is an interposed conductive coating between the granules and the deposit, separation difficulties frequently arise, and in addition it is quite diflicult to produce a continuous coating of metal over the base. The present element is therefore not only cheaper in cost, but superior in utility to those reviously suggested, and it has been found '0 at when metal is applied in a thin film to a base coated with a conductive granular material, as here described,

the base and metal are bound so securely together, that they cannot be stripped except by the exertion of considerable force.

While I prefer to make use of a granular material of substantial size, so that fairly pronounced irregularities are present in the surface on which the deposit is to be made, an improved bond is secured even when the particles are of quite fine size, and by a proper choice of the granular material employed, an

article may be reduced in which the metal coating has di erent textures due to the extent and character of the irregularities in it.

An asphalted felt affords certain advantages when used as the base of the new roofing elements, but it is evident that numerous materials may be used for this purpose, such as asbestos cement plates, and other similar products which are commonly used for roofing purposes.

This application is a division of my copending application, Ser. No. 618,246, filed February 10, 1923.

I claim:

1. A material for roofing and other purposes which comprises the combination of a foundation layer, a layer of electroconductive particles of substantial size afiixed to the surface of the foundation layer and giving that surface an irregular contour, and a layer of metal over the electroconductive layer.

2. A material-for roofing and other purposes, which comprises the combination of a foundation layer, a layer of non-metallic electroconductive granular material on one plane surface thereof, the granules having a substantial size to give the said surface an irregular contour and a layer of metal over the conductive layer.

3. A material for roofing and other purposes, which comprises the combination of a foundation layer, a layer of granular electroconductive material thereon, the granules having a substantial size and presenting an irregular surface, and a layer of metal over the electroconductive layer, the metal being of substantially uniform thickness and thus conforming to the irregularities of the'granular layer.

4. A material for roofing and other purposes, which comprises the combination of a foundation layer, a coating of a plastic substance on the foundation layer, a layer of granular electroconductive material partially embedded in the coating, the granules being of substantial size and presenting an irregular appearance, and a layer of metal deposited over the conducting surface provided by the granules and conforming to the irregularities of this surface.

5. A material for roofing and other purposes, comprising the combination of a foundation layer, a layer of granular electroconductive material aflixed thereto, this material including granules of different sizes with the finer granules lyingrbetween and contacting with the granules of larger size, whereby a surface having substantial irregularities is formed, and a layer of metal deposited over the conducting surface provided by the granules and having portions which extend into the depressions formed in the irregular surface between adjacent granules.

6. A material for roofing and other purposes, comprising the combination of a felted fibrous base of Waterproof characteristics, a coating of a plastic material having a high coeflicient of expansion applied to the surface of the fibrous base, a layer of nonmetallic electroconductive granular material over the coating, the granules being partially embedded therein and presenting an irregular surface, and a layer of metal over the conductive layer and conforming to the irregularities of the surface both on its outer and inner faces, such that the layer of metal has an iregular contour substantially corresponding to the contour of the granular layer.

7. A method of producing a material for roofing and other purposes, which comprises applying a plastic coating to the surface of a foundation layer, afiixing a layer of nonmetallic electroconductive granules to this coating by partially embedding the granules therein, the granules having a substantial size and giving the base an irregular contour and electrodepositing a layer of metal over the irregular conductive surface so provided.

8. A method of producing a material for roofing and other purposes, which comprises applying in heated condition, a coating of material having a high coeflicient of expansion to the surface of a base, aflixing a layer of electroconductive non-metallic granules of substantial size to this coating by. partially embedding the granules therein, cooling the.

coating to permit it to harden, and electrodepositing a layer.

9. A method of producing a material for roofing andother purposes, which comprises applying a coating of hot asphalt to the surface of the base, partially embedding granular material in the coating while the coating is still hot to form an irregular layer, and

- electrodepositing a layer of metal over the granular layer.

10. A material for roofing and other purposes, which comprises the combination of a fundation layer, a coating of plastic material having a high coeflicient of expansion applied to the surface of the said foundation layer, a layer of non-metallic electroconductive granular material partially embedded in the coating, and a layer of metal covering the conductive granular material.

In testimony whereof I afiix my, signature.

VTHOMAYS ROBINSON.

layer of metal over the granular

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