US1680497A - Impregnated fabric and process of making the same - Google Patents

Description

Aug. 14, 1928; 1,680,497

H. E. BROWN ET AL IIPREGNATED FABRIC AND PROCESS OF MAKING THE SAIE Filed Sept. 7, 1922 2 Sheets-Sheet 1 H. E. BROWN ET AL IIPREGNATED FABRIC AND PROCESS OF MAKING THE SAIB Filed Sept. 7. 1922 2 Sheets-Sheet 2 Patented Aug. 14, 1928.

UNITED STATES 1,680,497 PATENT OFFICE.-

' HERMAN E. nnowN, or KINGSTON, NEW YORK, m IormaN norms mom or NUTLEY, NEw JERSEY, ASSIGNOBS, BY mEsNE asammms, 1:0 mm nm, or PROVIDENCE, RHODE ISLAND, a CORPORATION 0E mom: IsLaNn.

IMPREGNATED FABRIC AND PROCESS OF MAKING THE SAME.

Application filed September 7, 1922. Serial No. name Our inventiom which is a continuation in part of application No. 493,526, filed Aug. 19, 1921, consists in the novel features hereinafter described, reference being had to the accompanying drawings, which illustrate diagrammatically a form of apparatus wh ch may be advantageously employed in carry ng our process into effect, and the said 1nvention is fully disclosed in the following description and claims.

The object of our Invention 1s to treat a fibrous fabric in which the fibres ex st in a more or less loosely'associated relation, the fibres being preferably unspun, unwoven natural fibres arranged in aflat form, as cotton batting, for example, or 1n a felted condition, as in cotton felt, for example, with a binding material, preferably waterproof and preferably a rubber compound, in the form of a semi-solid, that is to say, a dough br putty like form and plastic at the time of application, as distinguished from a socalled solution in which the binding material is dispersed in a more or less volatile liquid, and as distinguished from a material in a fluid or molten condition, and to mechanically force, by the application of pressure under the proper conditions of temperature, the said binding material uniformly into the fabric so as to coat the individual fibres throughout the entire fabric without completely filling the interfibre spaces, and uniting the fibres of the fabric by the cohesion of their individual coatings at points of contact and intersection, and in some instances by additional bonds from one fibre coatin to another so as to produce a resulting'fa ric which, when dried, cured or vulcanized, closely resembles leather, and is suitable for many of the purposes-for which leather is used. Where the binding ma.-

terial is a rubber composition and is there after properly vulcanized to convert it from the plastic to the elastic form, the resulting fabric possesses elasticity in all directions,

due to both the elastic quality of the binding material, which unites the fibres ieldingly at their points of intersection an bonding contact, and the .fact that the interfibre spaces are not completely filled, which permits relative .movement of the fibres with respect to each other, and contributes to the elasticity of the fabric as ordinarily produced. The resulting fabric is, pervlou's to air and dry gases, by reason of the minute 6'5 unfilled spaces between the fibre coatings, while it is practically impervious to water, owing to the fact that these interfibre spaces are so minute and the repellent action of the binding material is such, that water does not pass through in the absence of, pressure, and the fabric will not materially absorb water, as the coating of the individual fibres prevents the penetration of water thereinto.

We are aware that attempts have been made 55 to treat the, fibrous material by the application thereto of binding material in iquid form. Where a liquid mixture is employed,

the amount of liquid solvent or dis rsing agent 1s from ten to twent times t e bulk of the rubber or other binding material dissolved or dispersed therein. .Even if the fabric is thoroughly pepetrated by such a liquid, the drying out or evaporation of the liquid would leave not more than from five to ten per cent of the absorbed liquid, as solid matter (rubber for example) distrib-' uted among the fibres of the fabric, too little to effect either the coating of the fibres,

or the adequate binding of them together. 89

As a matter of fact, the amount of binding material left in the fabric is even lessthan would be expected, as rubber for example has a greater cohesion than adhesion and where a fabric has been treated with a liquid rubber mixture and subjected to drying action, the li uid mixture within the fabric flows from t e interior of the fabric toward the exterior in drying, thus. actually withdrawing the solution or mixture, as a mix- 90 ture, and including both the solvent and the dis ersed rubber from the interior to the exterror of the fabric in a manner somewhat similar to that resulting where a porous material, such as a brick, is saturated with a solution of a chemical solid and on drying the brick the dried solid is deposited, largely, if not entirely, at or upon the exterior surface of the-brick. We have found it to be a fact, by microscopic examinations, that where fibrous material of appreciable thick- .ness is treated withsuch liquid mixture central portion of the fibres being e binding material. Where any rubber or other binding material is left among interior fibres, it tends to collect in minute globules, and owing to itscohesion, it draws itself together and away from the fibres, leaving the interior fibres naked and uncoated. Where the fibres cross each other or'come in contact, they do not adhere to each other and are not united or bound together. Where they cross each other, a sharp line of crossing is noted under the microscope showing the bare fibres unattached. Moreover where fibrous material is treated by the liquid process it is extremely difficult if not impossible to carry materials insoluble in the dispersing liquid, such as oxide of zinc, whiting, magnesium oxide, sulphur coloring compounds, etc., into the interior of the fabric, as the fibrous material of the fabric acts in the same manner as a filter cloth in a filter press, to hold back such solid insoluble matters and prevent them from passing through into the fabric,

' thus leaving them on the outer surface.

In some instances it has been proposed to wring out or squeeze a liquid treated fabric between rollers or otherwise, but it will readily be seen that as this squeezing treatment removes a large percentage of the liq-' uid mixture which has penetrated into the fabric, the resulting amount of solid binding material left in the fabric when it is dried, s correspondingly reduced, and in fact is extremely minute. In accordance with our invention, we take a fibrous material, preferably composed of unspun, unwoven fibres, such as cotton felt, cotton batting and the like, for example, or any material made from natural fibres, and treat the same with binding material, preferably rubber compounds or plastic compositions, for example, in a semi-solid form, that is to say in a dough like or putty like mass of such composition and consistency, and plastie at the time of application, as to be capable of penetrating into the interfibre spaces of the fabric, and uniformly coating the fibres thereof, without filling completely the interfibre spaces, and leaving the fibres coated at their points of intersection and contact by the cohesion of the individual fibre coatings, and in some instances connected by additional bonds of the binding material between the fibre coatings. The material is preferably and ordinarily applied by the application of pressure, and preferably between calender rollers, the temperature and relative speeds of which are maintained in such a manner, according to the composition of the binding material em- Eloyed as to effect the stated result. The

bres as they pass between the calender rolls are compressed beyond a point at which they will be held in position by the plastic semisolid binding material in its then condition, forced into the fabric, and on the release of pressure, the fibres, by their inherent elasticity, tend to expand slightly and rearrange themselves, so as to form minute interfibre spaces, unfilled by the binding material, which is later set by the drying, curing or vulcanization of the resulting fabric.

We believe that we are the first in the history of the art to impregnate a non-woven material composed of unspun non-twisted and non-woven fibres by forcing thereinto a binding material in semi-solid condition, plastic at the time of application, and we believe that we are the first to accomplish this result by means of calendcr rolls.

Referring to the accompanying drawings, Fig. 1 is a form of apparatus which may be convenienttliy employed in carrying our process into e ect.

Fig. 2 is a diagrammatic view illustrating a form of apparatus which may be conveniently employed where the fabric is treated first from one side and then from the other, with or without afinal rolling to insure both sides of the fabric being smooth.

Fig. 3 is a diagrammatic sectional view illustrating the effect of the process on the fabric where the binding material is forced entirely through the fabric, leaving one surface of the fabric in a slightly roughened condition with upstanding coated fibres to serve as bonds for an exterior coating.

Fig. 4 is a similar view to Fig. 3 illustrating the effect on the fabric where the binding material is applied to one face and forced partly but not entirely through the fabric,

Fi 5 is a view similar to Fig. 3 illustrating t e completed fabric after a subsequent rolling operation, to smooth down the roughened surface and upstanding fibres left by a preceding application of the binding material.

Fig. 6 is a view greatly magnified illustrating actual fibres from the interior of the fabric as they appear under the microscope and illustrating more or less graphically the fibre coatings connected at their points of intersection and contact and additional bonds of the binding material connecting the fibre coatings.

As illustrative of our improved process, the following example is given of a specific binding material, and the specific manner in which it is a plied to produce our improved fabric. in this example, we use a composition consisting of 250'parts of washed and dried guayule rubber,

250 parts of smoked rubber sheets,

450 parts of zinc oxide,

. 25 parts of washed and dried flowers of sulphur,

15 parts of mono-chloro-naphthaline.

In preparing this compound the smoked sheets are first broken down or macerated on a mixing mill, as regularly employed in the rubber industry, by milling until the rubber is partiall or wholl denerved, which quality can be detected y pulling a piece of milled rubber apart between the lingers and observing the manner in which it separates, the denerving of the rubber be ing sufficiently complete when it pulls apart without the appearance of any lumps in the attenuated portions. Thebroken down sheets are then removed from the mill and the guayule rubber is placed on the mill and warmed by working. The broken down sheets are then added to the gua ule rubber and then the mono-chloro-nap thaline is added, and the mixture milled until it has a uniform consistency and color. The zinc oxide and the sulphur are then added and mixed until they are uniformly distributed throughout the mass. It will be noted that the materials above mentioned are brought into the semisolid plastic condition Without the use of volatile solvent, such as are employed in making so-called rubber solutions or cements. The mono-chloro-naphthaline is an oily material not volatile, the addition ofiwhich facilitates the softening and work ing ofthe rubber without injuring its qualit y or burning it, which might otherwise result unless the operations were most carefully watched, to prevent undue heat.

The compound is then transferred to a warming mill preparatory to feeding the calender upon which the compound is to be forced into the unwoven fibrous fabric. The mixing mill and calender maybe machines of standard approved types as used extensively in the rubber industry, in the manufacture of friction tire fabrics. Such a calender is illustrated in Fig. 1 of the drawing, in which 1, 2 and 3, represent a vertical series of three rollers provided internally with independent heating means which may be of any usual or desired character, and in this instance is indicated as a heating coil arranged within each of said rollers, said coils bein indicated by the numerals 4, 5 and 6, whic are connect'ed with pipes 7, 8 and 9 respectively, passing through the supporting trunnions of the rollers. The central roller, 2, is supported in stationary bearings and the up er and lower rollers 1 and 3 in vertically ad ustable bearings provided with any desired type of adjusting means by which variable pressure may be a plied. In this instance the bearings for t 'e rollers 1 and 3, indicated at 10 and 11 respectively, are shown as provided with adjusting screw shafts 12 and 13 respectively, which canbe operated by hand wheels,

. or in any other desired manner. The rollers 1, 2 and 3 are provided with means for regulating independently the temperature of each, which temperature adjusting means can be of any usual or desired character. In the present instance we have shown a steam pipe, indicated at 14, and a cold water within the rollers, and each of the branch pipes is provided with an inde endent controlling valve. The branch plpes for the roller 1 are indicated at 16 and 17, 'and the valves therefor, at 18 and 19 respectively.

The branch pipes for the roller, 2, are indicated at 20 and 21, and the valves therefor, at 22 and 23 respectively. The branch pipes for the roller, 3, are indicated at 24 and 25, and the valves therefor, at 26 and 27 respectively. The rollers are so geared that the center roller moves at a considerably faster speed than the others. The differential in speed of the center roller which We have found most suitable for the material given above is that of about three to one.

The calender is provided with the -usual feeding and rollingup devices (not shown) for the fabric. In treatin the fabric, the binding compound, in the orm of a dough like or putty likesemi-solid and plastic at the time of application, is applied from the warming mill to the calender between the top roller, 1, and the central roller, 2, as shown at 28. The temperatures of the various rollers are adjusted so that the mixed, milled compound adheres in a thin sheet to the central roller and does not adhere to the top roller. The bottom roller is well heated with dry steam to the desired. temperature. A few small strips of the cotton felt or other fibrous material to be treated, in which the fibres are ina more or less loosely associated condition, are first thoroughly dried, and are then passed through the calender between the central roller, 2, and lower roller, 3, with such adjustments of the upper and bottom rollers that the binding material is pressed into the fabric so as to uniformly coat the fibres without completely filling the interfibre spaces and leaving the fibres united by the cohesion of their individual coatings at their points of contact and intersection. The pressure of the rollers compresses the fibres beyond the point at which they will be held by the binding compound in its then plastlc condition, and the binding material is forced into the fabric, as above described so as to substantially uniformly coat the fibres. When the pressure is relieved as the fabric leaves the calender rolls, the fibres exp and somewhat by their inherent elasticityfid form interfibre spaces between the coatings,

ings. This will, of course, depend somewhat upon the weight and compactness of the fibrous material used. Where a cotton felt having a weight of four and a half ounces per s uare yard is employed, an adjustment of t e top and bottom rollers with respect to the central roller, so that a bank of the binding material is formed over the felt as it is enterin between the center and top rollers with a ank thickness of from one eighth to one quarter of an inch, is found to give very good results. After the proper ad uStment of the calender has been determined by the use of strips or pieces of the fabric, so as to secure the desired result, a continuous length of the unwoven fabric is drawn from a roll and passed through the calender. The supply of binding material is maintained b periodic additions of the prepare material from the warming mill. Th 'eight of the finished goods is about twe eounces per square yard. Where, for operating purposes, it is not desired to maintain the calender at such accurate adjustments, or where extra heavy goods are run, the goods may be passed through 'on one side and the binding material forced somewhat past the middle point, and then run through on the opposite side to complete the coating of the fibres and their union by the cohesion of their coatings, without complete- 1y filling the interfibre spaces.

As the fabric leaves the roller, 2, on the side opposite that from which it enters, the separation of the fabric from the layer of binding material, 29', on the roller, 2, leaves the surface of the fabric adjacent to the roller, 2, slightly roughened, and the'binding material being slightly tacky, any loose fibres on the surface, which are of course thoroughly coated, will be left in a more or less vertical .position, perpendicular to the surface of the fabric, as indicated diagrammatically in Figs. .3 and 4, and these upstanding coated fibres will form bonds for" firmly uniting to the fabric subseqgently any surface coating which it may e desired to apply thereto, as where the fabric is employed as a base fabric in the manufacture'of artificial leather and the like. Fig. 3 is a diagrammatic representation of the fabric as produced where the operation is so conducted that the binding material is caused to uniformly coat all the fibres throughout the' material in a single pass or operation. The surface adjacent to the roller, 2, is indicated as a roughened surface, at 32, and the upstanding coated fibresare diagrammatically indicated at 33. Fig. 4 is a similar'diagrammatic sectional view illustrating the fabric after it has been treated 'under conditions of speed and pressure, such that the binding material is caused to coat the fibres substantially .half way through the thickness of the fabric, theroughened surface adjacent to the roller, 2, being indicated at 34, and the upstandin fibres at 35. Where the process is carrie out in'this manner, the fabric is reversed and given another pass through the same or another similar apparatus, so as to force the binding material Into the reverse side of the fabric, and coat the fibres of the remaining portion, in which case the roughened surface, 3-1, and upstanding fibres, 35, of the previously coated surface, will be rolled down by contact with the smooth roller, 3, and the last treated side of the fabric will be left with a roughened surface and u)- standing fibres, as indicated in Fig. 3. f it is desired to have the fabric perfectly smooth on both sides, this can be readily accomplished by passing the fabric through a pair of plain rollers to roll down the roughened surface and upstanding fibres on the face last treated, leaving the fabric in the cFondition illustrated diagrammatically in In Fig. 2 we have illustrated diagrammatically, apparatus for treating the fabric on both sides by continuous operation. In this instance the fabric is first passed through an apparatus of the kind described, comprising rollers, 1, 2, 3, for the purpose of coating the fibres substantially half the thickness of the material, after which it is turned and passed between the proper rollers of another series of' rollers, 1, 2 and 3, constructed ,and operated in the same manner as hereinbefore described, the fabllC being turned in an usual manner, as by means of vertical gui ing rollers, indicated at 36. Where it is desired to have the fabric entirely smooth on both sides, the fabric, indicated at 31, may be passed between plain rollers 37 and 38, as indicated in Fig. 2, to roll down the face last treated, and leave the fabric in the condition indicated in Fig. 5, but where a surface coating of any kind is to,be applied to the fabric, it will be found distinctly advantageous to use it in the form indicated in Fig. 3.

The goods may be cured in rolls between sheeting upon drums in an autoclave at the following cure fifteen minutes at ten pounds open steam pressure, and an hour and a quarter at twenty pounds open steam pressure. When cured in the press, the goods should be cured for thirty five minutes at fifty pounds steam pressure in the steam jacket. The foregoing example states only one 'of a number of compounds which may be utilized in carrying our process into effect. With other compounds containin other gradesof rubber than those mentione above, along with asphaltum, mineral rubber substitute, Burgundy p tch, pasty substitute, brown and white factice, with various mineral fillers, such as litharge, whitin barytes, antimony sulphide, sienna, an

Ill

other inorganic and organic accelerators and dispersing agents, variations, in the calenden adjustments and cure will be required in line with general practice in the handling of'such compounds as may be constructed.

It is obvious that by varying the composition of the binding material, a wide range of properties of the resulting fabric can be obtained. I

The application of the binding material in dough like semi-solid condition by the aid of pressure, in the manner described, compresses the fibres so as to drive out the occluded air and permit the binding material to penetrate thoroughly and thoroughly coat the fibres through the entire thickness of the fibrous material treated. As the pressure is reli ved, there will ordinarily be a slight exgh-dsion of the fibrous material, due to the re iliency of the fibres. This causes the coated fibres to adjust themselves and separate slightly, but leaves them connected by the cohesion of their coatings at separated points, accumulations or agglomerations of the binding material resulting at their various intersections or points of contact, and frequentl additional bonds extend between the fi re coatings, which are plainly visible under the microscope, and when the resulting fabric has been hardened, cured or vulcanized, as the case may be, a fabric of great tensile strength results. Thus, in Fig. 6, which illustrates a number of fibres taken from the central portion of our improved fabric and magnified, 40, rep-'- resents the fibres, 4 1, the coatings thereof, connected at points of intersection and contact, as at 42, by the cohesion of the fibre coatings and 43, represent additional bonds of the binding material connecting the coatings of individual fibres.

An examination of ourimproved fabric under a microscope shows it to have an almost uniform. uasi-crystalline appearance,

- all of the fibres eing thoroughly coated and bound together b the cohesion of their coatings, and by bon s connecting the fibre coatings, without filling completely theinterfibre 3 aces, thus forming minute and substantia' lly. uniform interstices between the coatings of the fibres at point-s between the intersections and points of contact of said fibre coatings, and between said bonds.

. throughout the material. Our fabric, therefore, is clearly distinguished from fabrics in which fibrous material is incorporated in a solid "mass of rubber or other plastic produced by mixing and vulcanizing rubber or like material and causing it to solidify through and around the incorporated fibres or otherwise. In contra-distinction to this t pe of fabric our 'improvedfabric is'actul rvious'to air and dry gases and is. ne as rily much lighter and more flexible than those fabrics .in which a solid body of colloidal material surrounds incorporated fibres. At the same time our improved fabric, while pervious as before stated, to air and dry gases, is substantially impervious to water and many other liquids and is timetically waterproo We understand this apparent contradiction to be due to the fact that the fibres of our improved fabric are thoroughly and individually coated with the binding material so that they cannot absorb water, and the apertures or interstices between the adjacent fibre coatings are so minute and the repellent action of the binding material of the fibre coatings to water is so great that the water remains on the surface in somewhat the same manner as quicksilver will remain for the same reason on the surface of a piece of chamois leather, which air and dry gas will readily penetrate. A sheet of our improved fabric has been suspended horizontally and the convex portion filled with water and permitted to remain for ten or twelve hours without apparent absorption of Water into or penetration of water through the fabric. It will be readily understood that this peculiar and novel characteristic of our improved fabric fits it admirably, for purposes of clothing, on account of its extreme lightness and fiexiblity, its

water-proofness and its ventilating or breathing qualities. Another highly important feature of our new fabric is that when rubber is used as the binding material,

it is elastic or yielding in all directions due acteristic of our new fabric makes it particularly desirable as a substitute for leather or as a base fabric for leather substitutes. Cushions and other upholstery covered with our fabric will yield to pressure and reassume their original form without producing wrinkles which are soon formed in the ordinary leather substitutes, which, not being elastic, are soon stretched so as to produce a sa or'looseness in the coverings. Our new abric can be used with great advantage for waterproof clothing; for the uppers as well as for the soles and heels of shoes (in the case of soles and heels a number of superimposed layers of the fabric being employed and consolidated by the binding material), in all of which its elastic character is desirable, as well as for tarpaulins tents, boat covers, and all .purposes where a light and waterproof material is desired.

It also forms an admirable substitute for leather, and if desired, can readily be made entirely impervious, either b subjecting it to great pressure, or by t e application thereto of any of the usual or preferred types of coatings, such as varnish, the usual cellulose hitrate and cellulose acetate coating compositions, for example, or any other preferred coating compositions.

If a denser or heavier fabric is desired, we can readily produce the same by adding to the dough like or putty like rubber compound. or other binding material used, a desired preparation of solid insoluble material, such as, for example, oxide of zinc, whiting, magnesium oxide, sulphur oxide, and various coloring compounds, antimony sulphide, oxides of iron, gas black or lamp black, and various pigments which can be forced mechanically, as before described, into the interior of the fabric with and after having been thoroughly incorporated in the dough like binding material, thereby imparting any desired degree of density, thickness, weight, shade or color to the resulting fabric uniformly throughout the thickness thereof.

Our fabric can also be made denser and substantially, and in some cases, wholly impervious, by subjecting it to great pressure sufiicient to force the fibre coatings and fibres together and substantially close the interstices or interfibre spaces which would otherwise exist. This may be accomplished by subjecting a single sheet or a series of superimposed sheets, united by a rubber compound or other binding material, or cement, to great pressure, as in a hydraulic press, and such highly compressed material may or may not be vulcanized, as desired. Shoe soles and heels can be formed in any desired thickness in this manner, and would be impervious, and at the same time both flexible, and to an extent elastic, although not so elastic as the material formed without the use of this increased pressure treatment. Belting and straps can also be formed in this way, also floor coverings and like sheet materials.

' Our improved fabric can be given any desired color either by mixing pigments with the binding material, or otherwise. It can be used either with or without a surface coatin for book covers and many other uses w ere leather or imitation leather is now employed, and its elastic character adapts it espscially for such purposes, and for upho tery, automobile tops, etc., where it is stretched over unelastic surfaces or frames.

In the preparation of our improved fabric it may or may not be vulcanized after treatment, as before described. With the binding material such as described, we prefer to subject it to a drying, curing or vulcanizing action by any of the well known methods for treating such materials, such for example, as the festooning method, the curing chamber method, the autoclave method, or any other desired manner for the purposes of drying, curing or vulcanizing it.

iVhile our improved "fabric is substan-' tially impervious to water in that it will not permit the passage of water therethrough, nor will the coated fibres absorb water, we have found that a slight amount of moisture may be deposited in the interstices or interfibre spaces adjacent to the face of the fabric, especially if the fabric is subjected to pressure. For example, we have found by experiment that our new fabric is peculiarly suitable for use for the sweat bands of hats, and is much more desirable than a glazed imitation leather. When so used, the moisture of perspiration, instead of running down the band, upon the forehead, is held in the surface interstices of the fabric, and when the hat is removed, the moisture quickly evaporates on account of the permeability of the material to dry air. Where an elastic material is desired, the material is preferably vulcanized in such manner as to convert the binding material from the plastic to the elastic condition, and impart the desired degree of elasticity to the finished material.

We are of course aware of the fact that oalenders have been used for applying surface and so-called friction coatings to woven fabrics, and that in some instances the material of such surface coatings has been caused to enter between the crossed warp and weft threads, in substantially the same manner that plaster is pressed through supporting laths. In such instances, however, there is no coating of the fibres of the material, and on cutting such a material, the fibres of which the threads are composed will be found to be in their natural condition and the interior fibres uncoated and out of contact with the coating material. We beleive that we are the first to apply to a fabric in .which the fibres are in a more or less loosely associated relation, a binding material in a semi-solid condition and plastic at the time of ap lication, which we have referred to as a dough like or putty like condition, so as to cause it to coat the fibres without filling completely the interfibre spaces and leaving the individual fibres connected by the cohesion of their coatin s at points of contact and intersection, an we believe ourselves to be the first to apply a binding material to a non-woven fabric by means of a calender. It is extremely important thatthe bindin material be in the proper condition in or er that it may be caused to penetrate into the fabric and coat the individual fibres in the manner described. The composition must have a high degree of cohesion and also a high degree of adhesion,

so that while it tends to cling to itself, it will also cling around and coat the individual fibres. The condition of the binding mate rial may be aptly described as being substantlally that of a rubber base chewing gum which has been chewed at the temperature the onl method of impregnation heretofore.

eifecte It has heretofore been considered impossible to impregnate an unwoven fabric in any other way than by the Wet process, and we have demonstrated that this can be successfully accomplished by our improved process. proved fabric after impregnation in the manner described herein is from 1% to 3 times that of the original fabric, and the process may be carried out by a single pass of the material through the roll, or if preferred, by not more than two passes.

. We are aware of the fact that woven fabrics have been coated or frictioned with binding material, which is applied by means of a calender, but these processes have no bearing whatever on our process, and there is not the slightest resemblance between our improved fabric. and-the coated and frictioned woven fabrics produced by the old calendering methods. In the case of coatings, the coating material is usually applied in a very thin, almost liquid condition, and spread upon the surface of the woven fabric. In the case of friction tire fabric and the like, and in the manufacture of linoleums, the plastic material used is pressed upon the woven fabric. and will naturally extend into or through the orifices between the warp and weft threads, but this is entirely different from our process, as the plastic used in such frictioning and calendering processes merely extends part way around the twisted threads without penetrating into the interior thereof and withouticoating the individual fibres of the fabric at all.

What we claim and desire to' secure by Letters Patent is 1. The herein described process, which consists in applying to a fabric composed ofunspun unwoven natural fibres, ,a binding material in the form of a dough like semisolid plastic at the time of application, having such high cohesiveness and adhesiveness as to be capable of penetrating around and betweenthe natural fibres, and forcin said binding material by pressure into the abric and around and upon the individual fibres so as to coat the individual fibres throughout the fabric without completely filling the interfibre spaces and causmg the fibres to adhere at points of contact and intersection The increase in weight of our in1- by the cohesion 'of their individual coatings.

2, The herein described process, which consists in applying to a fabric composed of unspun unwoven natural fibres, a binding material in the form of, a dough-like semi solid and plastic at the time of application,

having suchhigh cohesiveness and adhesiveness as to be capable 6f penetratin around and between the natural fibres, an forcing 'said binding material by pressure into the 'fabric and around and upon the individual fibres so as to coat the' individual fibres throughout the fabric without completely filling the interfibre spaces and causing the fibres to adhere at points of contact and intersection by the cohesion of their individual coatings, and treating the resulting fabric so as to convert the bindingmaterial into an elastic material. H

3. The herein described process, which consists in applying to a fabric composedof unspun unwoven natural fibres, a vulcanizable binding, material in the form of a dough like semi-solid plastic at the time of application, and having such high cohesiveness and adhesiven'es's as to be capable of penetrating around and between the natural fibres, an forcing said binding material by pressure into the fabric and around and 'upon the individual fibres so as to coat the individual,

fibres throughout the fabric without com-' pletely filling the interfibre spaces 'and causing the fibres to adhere at points of contact and intersection by the cohesion of theirindividual coatings, and vulcanizing the resultin fabric so as to change the binding material from the plastic to an elastic consurface with pressure to a fabric composed of unspun unwoven fibres and forcing portions of said coating or binding material into the fabric and around and upon the individual fibres throughout the fabric, so as to coat the individual fibres without filling the interfibre' spaces, and separating the impregnated fabric from the coated rotary surface so as to leave the adjacent surface of the fabric roughened, and portions of the surface fibres coated and upstanding so as to form bonds for a subsequent exterior coatin 5. 'I he herein described process, which consists in applying to a "rotary surface, a

binding material in the form of a dough like semi-solid of such high cohesiveness and ads hesiveness as. to be capable of penetrating around and between the natural fibres of the material to be treated, applying said coated surface with pressure to a fabric. composed of unspun unwoven fibres and forcing portions of said coating or binding material into the fabric and around and upon the individual fibres throughout the fabric, so as to coat the individual fibres without filling the interfibre spaces, and separating the impregnated fabric from the coated rotary surface so as to leave the adjacent surface of the fabric roughened, and portions of the surface fibres coated and upstanding so as to form bonds for a subsequent exterior coating, treating .the opposite face of the fabric in like manner by means of a rotary surface coated with the binding material, and simultaneously treating the roughened previously treated surface of the fabric with pressure by a rotary surface free from binding material, to roll down the upstanding fibres and smooth the roughened surface thereof.

6. The herein described process, which consists in applying to a roller of a calender an adhesive coating of binding material comprising a rubber base plastic at the time of application, and made plastic by milling, and passing between said coated roller and an opposed roller, an unwoven fabric composed of unwoven unspun fibres to units said fibres in said fabric.

7 The herein described process which .con-

sul hur, and rendered plastic by milling wit out the addition of volatile liquid solvents, and passing between said coated roller and an opposed roller an unwoven fabric composed of unwoven, unspun fibres, to unite the fibresin the fabric, and then vulcanizing the fabric.

8. The herein described process which consists in coating a roller of a calender with binding material plastic at the time of application having a rubber base mixedwith sulphur and filling material, and rendered plastic by milling, and passing between said coated roller, and an op osed roller, under pressure, a non-woven abric composed of unspun fibres to unite the fibres in the fabric and carry the filling material with the other components of the binding material into the fabric.

9. The herein described process which consists in calendering an unwoven fabric composed of unspun fibres with a binding material in semi-solid form and plastic at the time of application, consisting of rubber mixed with sulphur and brought into plastic condition by milling, without the use of volatile solvents, to force said plastic binding material into the interfibre spaces of the plastic, and coat the fibres without completely filling the interfibre spaces.

In testimony whereof we ailix our signatures.

HERMAN E. BROW'N. JORDAN HOMER STOVER.

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