US1347095A - Waterproof fabric and process for producing the same - Google Patents

Description

A; B. HARRISON. WATERPROOF FABRIC AND PROCESS FOR PRODUCING THE SAME.

APPLICATION FILED MAY 17. 1915.

Patented July 20, 1920.

ATTORNEYS PATENT. OFFICE.

ARTHUR B. HARRISON, OF NEW YORK, N. Y.

WATERPROOF FABRIC AND PROCESS FOR PRODUCING THE SAME.

mamas.

Specification of Letters Patent.

Patented July 20, 1920.

Application filed May 17, 1915. Serial No. 28,536.

This invention relates to a novel fabric coated and saturated or impregnated .with a bituminous substance and particularly with asphaltic bitumen, and to a process for producing such a fabric; and it comprises, as a new article of manufacture, a fabric made waterproof, and particularly woven cotton fabric, coating and impregnating it with a suitable bituminous substance substantially free from solvents, oils and fluxes, said fabric being flexible without cracking at ordinary temperatures; more specifically it 5 comprises such a fabric coated and impregnated with relatively 'pure asphaltic bitumen of a melting point of about 175 to 200 F. forced into the fabric under pressure 1 when in a molten condition; it further com- 0 prises an elastic woven fabric such as drill which is elastic in' all-directions, and which is coated and impregnated with such bitumen or bituminous substance; and, as a process, it comprises a process of coating and impregnating such fabric with such bituminous substance by immersing the fabric in a molten mass of such substance, passing .the fabric while im- .mersed between a series of sets of steam 40 heated rolls for compressing the fabric and forcing the bituminous substance therein, passing the fabric after such treatment over a heated drum andsubjecting it to'further compression between rolls and such drum,

finishing and smoothing the fabric by means of heated finishing rolls, and cooling the res'ulting fabric; and it also comprises certain novel modifications of the product, and certain specific features and sub-combinations of the process; all as more fully hereinafter set forth and as claimed.

In waterproofing fabrics foruse in tunnels, foundations, and other sub-level structures, bridge and deck floors, etc., particularly Where the fabric is subjected to acids or alkalis, such as occur in cement structures or cinders, etc., it is important that the fabric be thoroughly saturated and impregnated as well as coated with the waterproof- 1ng agent. It is also important in many cases, for the fabric to be more or less elastic n order that it may readily accommodate ltself to unevennesses of the surface to wh1ch applied. Close fiber fabrics suchas tar paper or felt have little if any elasticity, and it is difficult to obtain more than a surface coating of such materials with bituminous material. It has heretofore been proposed to dissolve such bituminous substances m a solvent, or compound them with still bottoms, petroleum residues, volatile oils, or similar bitumen solvents, mixed or.

used as a flux, in order to make a more llquid mixture or solution for impregnatmg such fabrics; but in such cases the tendency is for the more penetrating solvent or flux to saturate the close fiber fabric and for the bitumen to be deposited only on the outside, the felt or paper acting as a filter for the bitumen. As a result, the fluxes and solvents tend to be retained in the fabric, and when the fabric'is used, as in sub-level conditions of waterproofing, the bitumen tends to soften and be disintegrated. The novel fabric of the present invention overcomes such disadvantages, and possesses besides particularly valuable properties which adapt it for general waterproofing uses, including uses where it is subjected to acids or alkalis or to the other disintegrating elements of sub-level construction.

' The fabric which I use in making my new waterproof membrane is cotton fabric. Cotton itself, consisting of nearly pure cellulose, is not readily attacked by acids or alkalis, and accordingly is much more resistant than many other fibers, such as, for example, burlap, whichconsists of hemp, a ligno-cellulose, and when treated according to the process of the present invention, it

becomes particularly resistant against attack. A particularly valuable form of cot ton fabric for use in making my novel waterproof fabric is that known as drill, a peculiar weave which is elastic in all directions, and which has a stretch of e. 9., 10 to 13% in all directions, without breaking. When waterproofed according to the present invention, it still retains its. valuable elastic properties, being thus capable of use on uneven surfaces where fabric of a straight Weave, capable of being stretched only on the bias, is less suitable. Accordingly, while I refer to cotton fabrics generally as ineluded within the invention, when treated as hereinafter described, I consider the waterproof membrane made of such elastic fabric as a particularly valuable and advantageous embodiment of the invention.

- The cotton fabric is treated and thoroughly saturated and impregnated with pure bitumen or a bituminous substance so that every fiber is thoroughly treated and rendered resistant and impervious to the action ofelements met with in belowgrade or sub-level work, and therefore is prevented from rotting or.- decay by such elements. The bitumen or bituminous substance which I may use in impregnating such fabric may be either coal-tar (freed from its more volatile constituents) or asphalt, or combina-- tions of both, or other suitable bituminous substance, free from flux or solvent. A form of bitumen which I have found after long and careful study and experiment, to be particularly advantageous, is asphaltic bitumen melting at approximately 190 F., or varying in melting point from about 175 F. to 200 F. Much higher temperatures are, however, necessary to make such a bitumen thinly fluid, e. g. around iOO F., but

since cotton tends to char or carbonize ataround 250 F such higher temperatures are precluded. Bitumens of lower melting point which are thinly fluid at lower temperatures, Whether of coal tar or asphaltic nature, often become sticky in hot weather tosuch an extent as to make their use impracticable, rolls of fabric impregnated with such lower melting-bitumens often becoming so stuck together as to prevent unrolling. In using the higher melting bitumens which cannot be used at temperatures which make them thinly fluid, the thorough impregnation of the fabric in order to obtain a uniform coating and impregnation of all the fibers, presents peculiar difficulties. Nevertheless, I effect such impregnation by the process and apparatus of the present invention in a particularly advantageous manner. In this process the bituminous substance is melted or liquefied and kept at a temperature not exceeding about 250 F. The fabric is immersed in this molten mass and while immersed is subjected to pressure successively by a series of rolls arranged in pairs, the fabric passing through the molten mass between the different sets of rolls, so that it is alternately immersed and squeezed or compressed. The fabric is then further compressed between heated -rolls after immersion, and is finally given asmoothing or finishingtreatment and cooled I before winding into rolls.

The accompanying drawing illustrates, more or less diagrammatically, and with parts in section, an apparatus appropriate to the production of the novel product of the present invention. This apparatus is made up of a vessel or receptacle 1 mounted, on supports 2 and arranged to be heated by the heating rolls therein, or by other suitable regulable heating means such as a steam jacket (not shown). Within the receptacle are five pairs of steam heated rolls 3, 4, spaced apart, between which the fabric is passed from the roll of raw cloth 6 and the idler 5. The steam heated drum 7 is arranged to be partly submerged in the molten mass within the apparatus, and rolls 8, 9 and 10 are arranged to press against this drum. Smoothing rolls 11 and 12, one above and the other below the fabric, are arranged to act thereon after the fabric leaves the roll 10,-and a cooling conduit 13 of a width sufficient to accommodate the fabric and of a suitable depth, 0. g. eight inches, is connected with a blower 14 arranged to discharge a blast of cold air against the fabric during its passage to the roll 15. The feeding of the fabric and the operation of the rolls, to vary their pressure and the tension of the fabric, can be regulated by any suitable means, not shown.

In carrying out the process of the present invention in the apparatus above described, the bitumen will be maintained in a molten condition by means of the steam heated rolls immersed therein or by means of other heating means (not shown), the temperature of the molten mass being maintained below that ofdecomposition of the fabric being treated. The fabric is unrolled from the roll 6 and passes up over the idler 5 and into the molten mass. There it passes successively between the five sets of steam contact with the molten bitumen between each passage through the rolls. Thus the bitumen upon the fabric is compressed in the fabric by each pair of rolls and the fabric is given five successive compressions following contact or immersion in the molten bitumen. The fabric then asses up over the steam heated drum 7 w ere'it is successively compressed by the rolls 8, 9 and 10. The steam drum is partly submerged in the molten mass and carries a layer of the bitumen up with it into contact withthe fabric. The action of these rolls pressing against the steam drum is to further compress and contact the bitumen within the fabric so that the desired coating and impregnation is insured. The fabric then passes between the two finishing tubes 11 and 12 heated to a temperature of 'e. g. 200 F., by steam, one tube scraping the cloth on the upper side and one on the lower side. These tubes act as smoothing or finishing ne ates such treatment is flexible at all ordinary temperatures so that it can be folded back upon itself any number of times without cracking or fracture, and it will remain in the roll at high temperatures, even up to about 150 F., without sticking or bonding together, so that it can be easily unrolled when desired. When the fabric used is of an elastic nature, such as drill, the treated and waterproofed fabric will still be elastic and will have a stretch of about 10% in any direction without breaking. Accordingly the fabric can readily conform to any unevennesses in the surface to which it is applied without leaving pockets bridges or air I holes. The cotton fabric, moreover, is much coated and impregnated with an inert bitustronger than many of the closer fiber fabrics, such as felt and paper. For general waterproof purposes the cotton fabric should be able to withstand a weight of at least 125 pounds per inch without breakage. The novel fabric of the present invention, made up of cotton which is itself chemically inert to acids and alkalis, such as are usually met with in sub-surface waterproofing, is by the present invention thoroughly men, advantageously of asphaltic origin, which is compressed within the fabric and which is free from fluxes and solvents. Such a bitumen is tough and inert and when containing, for example, 98% hydro-carbon, is not aflected by concentrated acids and alkalis. The fabric moreover contains no oils which might cause disintegration or rotting of the fiber, or softening of the bitumen when used. Such a fiber when saturated with a bitumen of sufliciently high melting point is efficient under all weather and climatic conditions. It isadapted for use as a membrane for water-proofing foundations of buildings or of other structures, in tunnels, on the floors of bridges or decks, or in general wherever a waterproof fabric is desired capable of withstanding disintegrating conditions. The fabric may be made of dif ferent weaves, weights and thicknesses, in order to adapt it for different uses. Since the only material-used for impregnating is the pure bitumen, the fabric can advantageously be used as a binder between differentlayers of bitumen, the bond in such cases being between bitumen and, bitumen on both sides. While I have described what I now believe to be the best method of producing such a fabric, yet it will be understood that the invention is not limited to the exact method and apparatus described, although such method and apparatus are particularly advantageous, but it will be understood that variations and modifications can be made in the specific embodiments of the invention described without departing from its spirit and scope.

I claim:

1. As a new article of manufacture, a woven cotton fabric coated and impregnated at a temperature below that injurious to the cotton fabric with a hot fluid bitumen ductile at all ordinary temperatures and subwoven cotton fabric coated and impregnated at a temperature below that injurious to the cotton fabric with a hot fluid asphaltic bitumen of a melting point of about 175 to 200 F. and substantially free from bitumen solvents and fluxes, said coated and impregnated fabric being flexible at all ordinary temperatures.

4. As a new article of manufacture, an elastic woven cotton fabric coated and impregnated at a temperature below that injurious to the cotton fabric with a hot fluid asphaltic bitumen of a melting point of about 17 5 to 200 F. and substantially free from bitumen solvents and fluxes, said coated and impregnated fabric being flexible at all ordinary temperatures, and being elastic and capable of being stretched about 10% in all directions.

5. The method of coating and impregnating woven cotton fabric and of producing therefrom a fabric coated and saturated with a bituminous substance substantially free from bitumen solvents and fluxes, which comprises passing the fabric through a molten bituminous substance substantially free from bitumen solvents and fluxes at a temperature below that injurious to the cotton fabric and subjecting the fabric to compression between heated rolls during its immersion, whereby the bituminous sub stance is forced into the fabric mechanically without the aid of solvents and fluxes.

6. The method of coating andimpregnating woven cotton fabric and of producing therefrom a fabric coated and saturated with a bituminous substance substantially free from bitumen solvents and fluxes, which comprises passing the fabric through molten asphaltic bitumen heated to a tem perature below that injurious to the cotton fabric, said bitumen being substantially free from bitumen solvents and fluxes, and subjecting the fabric to alternate compression between heated rolls and exposure to bitumen during its immersion, whereby the bituminous substance is forced into the fabric mechanically without the aid of solvents and fluxes.

7. The method of coating and impregnating woven cotton fabric and of producing therefrom a fabric coated and saturated I with a bituminous substance substantially free from bitumen solvents and fluxes, which comprises passing the fabric through a molten mass of asphaltic bitumen melting at about 175 to 200 F. heated to a temperature below that injurious to the cotton fabric and subjecting the fabric while passing through the molten mass to repeated compression between heated rolls, the action of the rolls being sufficient to cause the desired impregnation or saturation of the fabric with the molten bitumen without the use I of bitumen solvents and fluxes.

worked into the fabric mechanically while immersed, and whereby the fabric is further subjected to the mechanical impregnating action after immersion.

9. he process of coating and impregnating fabrics which comprises passing the fabric through a molten mass of asphaltic bitumen melting at about 175 to 200 F. maintained at a temperature below about 250 F. and successively subjecting the fabric to compression between heated rolls and to contact with the bitumen, subjecting the fabric after immersion to further compression betweena drum heated to about 250 F., and a series of coacting rolls, and cooling the fabric.

10. The process of coating and impregnating fabrics which comprises passing the fabric through a molten mass of'asphaltic bitumen melting at about 175 to 200 F.

250 F. and successively subjectingthe fabric to compression between heated rolls and to contact with the bitumen, subjecting the: fabric after immersion to further compres sion between a. drum heated to about 250. 5

F., and a series of coacting ro11s,'smoothing the fabric by passage between finishing rolls heated to about 200 F., and cooling t e fabric.

11. The process of coating and impregnating fabrics which comprises passing the fabric through a molten mass of asphaltic bitumen melting at about 175 to 200 F. maintained at a temperature below about 250 F. and successively subjecting the fabricto compression between heated rolls and to contact with the bitumen, subjecting the fabric after immersion to further compression between a drum heated to about 250 F., and a series of coacting rolls, smoothing the fabric by passage between finishing rolls heated to about 200. F., and cooling the fabricby subjecting the same to a blast and current of cold air.

In testimony whereof I affixm si ature.

- ARTHUR B. HAl R SON.

65 maintained at a temperature below about '1

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