US2104082A - Building material and process of making same - Google Patents

Description

Patented Jan. 4 i3 ears are,

orries aromas 'BHNG MATERIAL AND PRQPUESS @lF MAKHNG Shit/HE Lester Kirschbraun, New York, N iii, assignor,

by mesne assignments, to The Patent and Lilcensing (Corporation, New York, N. 3Y a corporation oi li iassachusetts No. rarer ills-inns.

This application is a continuation of my copending application Serial No. 615,472, filed June i, 1932 as a division of my co-pending application Serial No. 519,432, filed March 2nd, 1931.

This invention relates to composite building material especially adapted for use as roofing material, siding material and like purposes.

An object of the invention resides in the production of building material having a surface coating on one or both faces thereof possessing weathering properties far superiorto those attainable with asphalt coating now commonly in use in the commercial production of composite roofing material.

Another object of the invention resides in the provision of a coating layer on one or both faces of a suitable base material which by virtue of its own peculiar properties will impart to the product a high degreeof fireprooiness.

Still another object of the invention resides in the provision of a product having one or both A faces thereof coated with material of a character such that it is capable of withstanding internal flow at high temperatures and other action of the weather which are destructive of asphalt coatings as now commonly used.

In the asphalt roofing industry at the present time large quantities of products are made in a wide variety of forms'and shapes in which a base of felted fibrous material suitably impregnated with a saturant such as low melting point asphalt, is coated on one or both facesthereof with a layer of blown asphalt applied in molten condl tion to the base. The destructive action of the sun and weather upon coating of this kind is well known. The destruction of this coating material is apparently due to polymerization induced by the suns rays, causing a hardening of the outermost surface of the coating. Under the action of elevated temperatures, this hardened or brittle outer surface tends to undergo a form of minute fiow as a result of the internal flow and contraction of the hardened outerlayer over the, as yet, unpolymerized portion, which brings fresh material to the surface. The cumulative effect of this action causes numerous cracks and checks to form in the surface layer into which cracks the softer and still. unaffected portions how and themselves become subject to the polymerizing action. The net result is that intime, the entire coating becomes badly checked and cracked throughout its depth; These cracks and checks permit ready access of water and moisture to the base material and cause deterioration thereof.

The invention, in one of its iormsis adapted to (cl. ai esi the manufacture of roofing as well as siding, sheathing and other building material having as its base a foundation of felted fibres such as rag,

vegetable, asbestos and similar fibres formed into a web on any standard felt making machine. It is to be understood, however, that the invention is not restricted to use in connection with a base comprising a felted fibrous foundation but is ap plicable to products in which the base may be of wood, asbestos cement compositions, and other well known base materials suitable for roofing and other building purposes.

Briefly stated, the invention consists in the use or a dispersion of waterproofing material, such as asphalt, in water, for coating the surface or surfaces of any desired type of base material to be employed for the purpose indicated. The dispersion in accordance with the invention is one which is made in such a way and with essentially inorganic or mineral dispersing agent of such a character that when the water content has evaporated and the dispersed particles have coalesced, will produce a resultant film. in which the material employed as the dispersing agent occurs in the form of a. gel or honeycomb structure of such a nature as will impart mechanical stability or staticity to the dried film. I

The suitability of aqueousdispersion of bitumen for accomplishing the objects of the invention may be observed and recognized by a microscopic examination, according to the following technic: a very thin film of the dispersion is painted out on a microscope slide, the film being sumciently thin to transmit light, and the specimen is then allowed to dry thoroughly; the dried specimen is then washed with benzol or other bituminous solvent for leaching away the bitumen by placing the slide in an inclined position and dropping the solvent upon the slide at the upper end thereof so as to allow the solvent to flow or run over and away from the dried specimen, the operation being thus continued until all the bitumen is leached out as evidenced by the disappearance of the black or dark color thereof; the solvent is then allowed to evaporate completely fromthe specimen upon microscopic examlna- I tion of the residual material of the specimen, one should observe a honeycomb or cellular structure with the shape of the individual cells resembling rather closely the shape of configuration of the bituminous; particles originally contained in the aqueous dispersion. Aqueous dispersions,

the dried films of which possess adequate mechanical stability for accomplishing the principalobject of the invention respond to the fore- .180 F. melting point steam reduced asphalt is preferably employed and may be made in accordance with Patent'No. 1,734,437, granted to me November 5th, 1929. More particularly the dispersion is preferably, in accordance with the invention, one which is made with material such as 'bentonite as the dispersing agent. A characteristic and noteworthy property of a dispersion of this character is the .infusibility of the dried film of the dispersion. That is to say, the dried film under the action of high heat as for instance the heat of a direct flame or other action, will ash itself in place without exhibiting any movement relative to the base. The importance of this property of the coating material from the point of view of fire protection afforded thereby, will at once be apparent to those skilled in the art. If the heat that may thus develop is as high or even higher than the melting point of the asphalt, the mechanical stability of the film and its resistance to flow will prevent the coating from flowing and even if the heat is sufiiciently high to cause the asphalt to ignite, the asphalt will form into a carbonized crust and ash itself in place.

I have further discovered that a coating material in the form of a dispersion as indicated exhibits greater and more firm retention of surfacing material such as crushed mineral grit, than do the ordinary coatings of asphalt in molten condition.

The film of wet dispersion coating oifers no resistance or impediment to the reception of or impingement by granular surfacing material,

which thus becomes readily partially submerged in the coating layer and surrounded and wetted on the lower portions thereof with the soating material. Then as .the water of the dispersion is evaporated through the interstices between adjacent granules and the thickness of .the coating layer becomes correspondingly decreasedthere is left upon these portions of the granules a film of asphalt extending outwardly of the general plane of the dried coating layer to a height correspond- "ing to the original thickness of the wet dispersion hibits no tendency to blistering such as fre-v quently occurs with the usual coatings of molten thereof, as abovepointed out, offer the advantage that comparatively thinner final films of coating material may be employed with far ,bet-

ter resistance to weathering action,.and greater relative orcomparative quantities of mineral surfacing may be forced. into or embedded in ,the

' coating layer.

Thus, where a dispersion of the character herein described is applied atsuch a rate as to leave a dried coating film of such thickness that say sixteen pounds of asphalt cover one hundred square feet or surface, crushed slate to the amount of sixty pounds per one hundred square feet may be readily-applied. Similarly where the coating is applied in thinner films, as for example to provide a coating in which say nine pounds of asphalt (dry weight) cover one hundred square feet of surface, mineral surfacing to the extent of about twenty-five pounds per one hundred square feet may be employed. This is in marked contrast to the manufacture of mineral surfaced material in which-molten asphalt is employed as the coating material, where under normal conditions the' ratio of surfacing to coating per unit generally is about one to one, and even under extraordinary conditions of applying the surfacing, as e. g. using heated slate and severe pressure for embedding the same, this ratio does not exceed two to one.

Another important feature of the invention which results from the use of aqueous dispersions as coating material is the ease with which mineral or inorganic fillers may be incorporated in the coating material to providebulking and/or weighting effects such as may be obtained by the use of slate dust, finely ground diatomaceous earth, or the like. Mineral fillers as well as oer-- tain watersoluble, fireproofling saltsmay readily be incorporated in the coating material to a controllable and greater extent than is possible with molten asphalt.

In adapting the invention in practice to the production of roofing or siding material in which the base consists of a felted fibrous foundation, the latter may firstbe impregnated with a waterresistant material such as asphalt in any convenient or suitable manner. In order that the layer of coating material may not be susceptible to sliding over the roofing base due to the presence of an excess of the saturant on the surface thereof, the step of impregnation should be carried out and so regulated as to ensure all of the saturant being soaked or drawn into the pores of the base and the surface excess substantially completely removed before the dispersion coating is applied. In this way there will be no superficial film of the relatively low melting point saturant interposed between the base and the layer of dispersion coating to give rise to any sliding of the coating layer over the base. Accordingly after the step of impregnation hasbeen properly carried out as u indicated. a film of the asphalt dispersion may be applied to one or both surfaces thereof in any convenient way, the application of the dispersion being regulated so as to forms. film which upon elimination of water will be of a thickness from say 0.010 inch up to approximately 0.050 inch.

Inasmuch as elimination of the water from the dispersion coating results in an appreciable de-. creafse'in the thickness of the layer applied, it

will be understood that due account should be taken of this factor inaccordance with the water content of the dispersion employed.

Where the product is to carry a surfacing layer of comminuted grit or the like it is important to apply the surfacing material to the coated sheet while the coating layer is still substantially wet, and in any event before sufficient water has been eliminated to bring about the condition in which the honeycomb or gel structufe of'the coating film is about to begin to form, as otherwise the application of the comminuted surfacing material may interfere with the formation'of the gel or honeycomb structure and impair the mechanical I stability or the static nature of the final dried coating layer which provides the fire resisting ioaoea properties above pointed out. I have found that with dispersions containing approximately 40% water in the external phase thereof, it is not well may, however, vary with variations in the water content of the particular dispersion employed.

Furthermore, in order to realize the advantages of the invention as heretofore described, it is desirable that the size of the comminuted surfacing material be regulated in accordance with the thickness of the dispersion layer in order to avoid, during the subsequent processing, exudation of the wet dispersion coating upwardly through the interstices between the particles of surfacing material when the surfaced base is conducted over, around or in contact with various parts of the machine, as in the manufacture of felt base material where the operation requires at sundry times,passing the sheet around drums for various purposes, as will tie-hereinafter explained. Thus, for example, where the coating film is about 0.010 inch in thickness, the surfacing material should be of such a size that it will pass a screen of iii mesh and be retained on a screen of 30 mesh. On the other hand, where the coating layer is of a thickness approximately 0.025, the surfacing material should be of such size as to pass a screen of 6 mesh and be retained on a screen of 20 mesh. An advantage of the invention resides in thefact that the surfacing material when applied to the wet film assists materially in the subsequent elimination of water from the film by virtue of the capillary spaces between the adjacent par ticles of the surfacing material and also the porous nature thereof. employed in the manufactureof products from a foundation sheet of fibrous material which is first impregnated with molten saturant such as low melting point asphalt, the residual heat in the saturated or impregnated sheet further assists in the elimination of water from the coating layer.

After the surfacing material has been showered upon the wet film of the coating as abovedescribed, the coated and surfaced material may then be subjected to drying conditions whereby the water contained in the coating film may be progressively expelled therefrom as rapidly as possible without causing ebullition, after which the facing materialthereto before or afterbeing subjected again to drying conditions for completely drying the coating layer on the reverse face; finallyv passing the sheet over cooling drums and/or through a cooling stage.

The invention also finds adaptation and affords a marked advance in the production of building material in which the base is of wood. I have found in accordance with the present invention that the dispersion material as heretofore described, when applied to a wooden base serves, in addition to a weather protection medium to impart to the wood base a substantial degree of fireproof qualities by virtue of the infusibity. and static qualities of the resultant bituminous coat- Where the invention is ing layer. The fireproofness of the base may be still further increased by incorporation of soluble fire roofing salts such as ammonium phosphate, in the dispersion, which will penetrate into the wood base when the aqueous dispersion is applied thereto, so that upon elimination of the water, these salts will be present in the pores of the base and impart additional fireprcofness thereto.

The dispersion coatings as herein described, are

likewise advantageous in the production of building materials in which the base is of metal, such as corrugated sheet iron. In such cases the dispersion coating material may serve a weather protective and. rust inhibitive median or it may have incorporated therein rust inhibiting materials such as soluble chromate salts, for this purpose.

Rigid materials such as asbestos cement compositions, as commercially made from mixtures cement composition shingles are made by a wetmachine operation, as illustrated for example in patent to liedebcer No. 1,790,822, the dispersion coating and an overlying layer of surfacing material may be applied to the formation strippedv from the collecting cylinder or malze-up roll of the fabricating machine, after partial or complete elimination of water from the base sheet or slab, I

andafter the dispersion layer has been dried to the desired extent, units of desired size and shape may be cut in any convenient way from the slab.

If desired, the coating material may be applied as indicated to asbestos cement shingles after they have been formed of the desired size and shape in accordance with practice known in the asbestos cement shingle art. Thus, the asbestos cement shingles may be sprayed with, or immersed in a bath of, the dispersion coating material, the coating being applied in the desired thickness and the coating step followed by a surfacing operation under conditions as herein described. In any event, the weather and wear resisting properties of the asbestos cement type shingles may be enhanced in accordance with the invention. An added advantage of coating this type of shingle with dispersion coatings as herein described resides in the fact that mineral surfacing of various colors may be applied to producecement type shingles in a variety of, colors without necessitatf ing the use of expensive pigments as is now required in the asbestos cement shingle art. The coating material as thus applied to asbestos cement shingles also functions as a cushion to pre-- vent breakage of the shingles in the packages during handling and transport due to the normally fragile character of these shingles. 'Moreover, since the aqueous dispersion may be readily applied to the wet formation stripped from the col lectlng cylinder, as well as to the partially or completely dried slab, as explained above, the dispersion may thus be made to serve as a medium for insuring proper curing of the asbestos-cement.

tion as heretofore described will be appreciated by those skilled in the art, it may be pointed out here that this invention comprises a radical de-. parture in the roofing industry for the manufacture of composite roofing or like material, and also that other types of emulsions, the dried fllms of which do not have the resistance to flow or the mechanical stability andstatic properties of the dispersions employed in accordance with my invenion, as well as cut-backs or similar compositions which require fibre to reinforce the coating and to prevent fiow thereof, do not possess the weatheringability and other advantages that accrue from the present invention. Where fibres are employed to reinforce the film and prevent flow, they exhibit a tendency to absorb moisture as soon as the film surrounding the fibres have undergone the least weathering action. sorption of moisture by the fibres may then cause the fibres to swell and induces cracking of the coating particularly under frost action and additionally the fibres, being of organic nature, are

as set forth in the appended claims,

minuted material to said surface.

I claim as my invention:

1. In the process of producing shingles of the asbestos-Portland cement composition type, the improvement which comprises the steps of applying to a surface of the formed composition a coating layer comprising an aqueous dispersion of hitumen, partially embedding comminuted surfacing material in said layer, and drying the thus coated composition to remove the water of said dispersion layer and thereby bind the said com- The ab- 2. In the process of producing shingles of the asbestos-Portland cement composition type, the improvement which comprises the steps of applying to a surface of the formed composition before complete drying of the latter, a coating layer comprising an aqueous dispersion of bitumen, partially embedding comminuted surfacing material in said layer, and drying the thus coated com-' position whereby to complete the setting of the asbestos-Portland cement composition and simultaneously to remove the water of said dispersion layer andthereby 'bind the said comminuted material to said surface.

3. As an article of manufacture, a shingle of asbestos-Portland cement composition havingthe surface thereof to be exposed to the weather coated with a layer comprising a water-free film of an aqueous dispersion of bitumen, said coating .film having the dispersing agent distributed therethrough in a honeycomb structure, said film having comniinuted surfacing material partially embedded therein to furnish a wear-resisting and decorative layer for said coated surface.

4. Asan article of manufacture, a shingle of asbestos-Portland cement composition having the surface thereof-to -be exposed to the weather coated with a layer comprising a water-free film of'an aqueoiis dispersion of bitumen, said coating film having the dispersing agent distributed therethrough in (a honeycomb structure, said film having comminuted surfacing material partially embedded therein to furnish a wear-resisting and decorative layer for said coated surface, individualparticles of said surfacing material being LES'I'ER KfRscHB AUN.