US 2689811 A
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Description (OCR text may contain errors)
p 1954 E. R. FREDERICK ET AL ,6
CORRUGATED FIBROUS BATTINGS Filed June 12. 1 950 3 Sheets-Sheet l INFLUENCE OF BHTT STRUCTURE ON COMPREI'SION RES\STANCE (L 15 I O LAMINATED BATT BEFORE FLEXING LAMINATED BATT AFTER 5,000 FLEXINGI 0110 I CORRUGATED BATT BEFORE FLEXlNC-S F, El CORRUGATED 'BATT AFTER s oo FLExme/ 5 035 Z Q Q 050 Lu Z 5 025 i F D DJ 0.2 0.3 0. 0.5 0.6 0.1 0.8 0.9 L0
PREf/URE p.42 1
' INVENTOR r Edwor) R.Freo erIcI M4 Mr'cwae' CJcukbwjki W/d wm ATTORNEY- Se t. 21, 1954 E. R. FREDERICK ETAL 2,639,311
CORRUGATED FIBROUS BATTINGS 3 Sheets-Sheet 2 Filed June 12, 1950 INVENTORJ Edward R Frederic l4 CORRUGATED BATT/ BY I ATTORNEY Sept 21, 1954 E. R. FREDERICK ET AL 9,811
CORRUGATED FIBROUS BATTINGS Filed June 12, 1950 3 Sheeis-Sheet 3 CARDlNG OF LOO/E FIBER] TO FORM A CARDED WEB OF ORIENTED FIBER! EXTENDING PRINCIPALLY LoNcnumNAL v OF THE WEB PLURALITY OF n CONTINUOUJ CORRUGAHNG MONO'FILAMENTJ FEDI DIVIDUALLY MACHINE N CORRUGATED was WITH CORRUGATED REINFORCING MONO-FILAMEN'TI ExTEnDmc.
LONGITUDINALLY AND SPACED TRANSVERSELV 0F we was I l I QUI'LTED F ADD NOTLESS THAN RE 5 7 B we'nsH'r E D I D OFAN ELASTOME'R A I i- INVENTORS 8 ATTORNEY Patented Sept. 21, 1954 CORRUGATED FIBROUS BATTINGS Edward R. Frederick and Michael C. Jaskowski, Pittsburgh, Pa., assignors to the United States of America as represented by the Secretary of the Army Application June 12, 1950, Serial No. 167,614
1 Claim. 1
The present invention relates to novel fibrous battings and a method of making the same. Such battings may be quilted or unquilted and will make desirable coat linings, fillings for comforters, and, in general, heat-insulating and cushioning layers.
In addition to flexibility and insulation, resistance to compression is an important desideratum of a cold climate garment-filling material, since its efiicacy is seriously restricted unless it withstands moderately high pressures without permanent compression or pronounced temporary compression. Theoretically, a fibrous filler will have maximum compression resistance for the particular filler if all of its fibers or filaments are oriented to take axial compressive stresses and if the filler is in the form of a corrugated structure in which the ridges of the corrugations run at right angles to the lengths of the oriented fibers. If the corrugations are formed or compressed so as to be close together and a load is applied in the direction of the multiplicity of columns formed by the oriented fibers, or in other words, if a load is imposed transversely of the corrugations, the fibers as well as thecorrugations resist the load to a maximum extent.
Ingeneral, the invention aims to provide a batting or filling which approaches as closely as possible to this ideal fibrous filler and will not break down as an insulating layer after being subject to many thousands of fiexings. Expressing the matter otherwise, the invention aims to provide a batting which, under normal conditions, Will be sufficiently durable to withstand extended periods of service without substantial deterioration due to fiexure or compression. An ancillary object is to provide a cushioning andinsulating material which is highly porous, light weight, inexpensive, and of exceptional resiliency. Other objects will appear from the following description of several embodiments of the invention and of methods and apparatus for making the same.
In the accompanying drawings forming a part of this specification,
Figures 1, 2 and 3 are diagrammatic cross sections of three corrugated battings;
Figure 4 is a fragmentary plan View of a quilted batting;
Figure 5 is a fragmentary cross section through the batting of Figure 4, the fibers being illustrated more or less diagrammatically;
Figure 6 is a series of curves showing the influence on compression resistance of wool batting structures embodying the invention;
Figure 'l is a perspective View of a simple hand- 2 operated laboratory machine for corrugating wool or similar webs;
Figure 8 is a perspective view of another corrugating machine;
Figure 9 is an end elevation of the same on a larger scale, showing aweb in the process of being corrugated and omitting distant parts;
Figure 10 is a schematic diagram of a modified process wherein mono-filaments are incorporated into the batt;
Figure 11 is a fragmentary perspective view of a corrugated batting reinforced with monofilaments, the showing being diagrammatic;
Figure 12 is a diagrammatic vertical section on an enlarged scale of some of the parts used in corrugating a web by means of the machine of Figure 'l; and
Figure 13 is a diagram showing how parts of the machine of Figure 7 move when forming the corrugations, three different positions being shown.
Referring first to Figures 1, 2 and 3, which show diagrammatically corrugated battings in cross section, batting I0 (Figure 1) is of loose construction and very low density, yet its: compression resistance is superior to that of conventional fibrous battings. The batting l I of Figure 2 is of moderately tight construction and has moderately high compression resistance and insulation efficiency. Figure 3 shows a batting 12 of rather high compression resistance and insulation efiiciency, but its density per lineal foot will be much greater than that of batting Hi.
The corrugated battings of Figures 1, 2, and 3 may be made from carded. wool webs or similar fabrics. When carded webs are employed, the fibers extend generally in the same direction or are oriented. A Web is usually understood to mean the product of one doiier roll of a carding machine, said product being so porous as to be quite fragile. The web maintains its form through the interlacing effect of a very small proportion of the curly fibers that extend at an angle to the direction of the Webs motion on the take-off conveyor. To make a batting of the desired body or weight, one or more of these webs, sometimes as many as eight or more, one on top of the other, are fed as a combined web to a corrugating machine, with the fibers extending longitudinally or inthe direction of the feed. Corrugating may be effected in several ways: by machinessuch as the well-known cloth pleating machines manufactured by Chandler Machine Co. of Ayer, Massachusetts, or by modifying slightly the construction andoperation of a carda ing machine in the manner explained below, or by apparatus embodying the principles of either of the laboratory machines which will now be described.
Referring to Figure 7, a corrugating machine is shown as fixed to the top of a table I which also supports a l-ply (combined) wool web Hi, presumably discharged from the carding machine (not shown) with the fibers oriented in the direction of the discharge. A main shaft H has a crank arm i8 secured to one end to permit turning it, or a motor drive of conventional design may be used. Shaft l1 drives a parallel countershaft at the same speed by means of a sprocket wheel 2! fixed to it and a sprocket chain 23 meshing with wheel 2! and with sprocket wheel 25 fixed to the countershaft. Both shafts and their connecting mechanisms are spaced above the table top so that the web it may freely move along the table. At the opposite ends of the countershaft a pair of eccentrics 2?, 28 are fixed, and to each eccentric an arm 29 or 30 is pivotally secured. Arms 29, 3B are parallel and are secured at their outer ends to a corrugating blade 3! whose outer edge is adapted to engage the web and at other times is supported above the web and the table top. Resting on the table top is a web-receiving frame 32 of U-shape, preferably with a sheet of plate glass 33 spaced above the table top, and a straight bar 34 which might be termed as a follower-bar, as it is pushed along the table top by the corrugated web. Bar as extends from one side of the frame 32 to the other and lies beneath the glass sheet 33. Finally, a set of juxtaposed but separable, flat, straight, relatively heavy metal straps 35 are placed edge down on the table top parallel to the corrugating blade 3! but spaced a short distance therefrom with the ends of the U-shaped frame 32 supporting the straps in a nearly upright position. See Fig. 12 also. These straps form a temporary webgripping means as will be described.
Operation A batt to which is to be corrugated is placed on the top of the table and run under shafts ll, 2&3 and under the corrugating blade 3| and extends to bar 34, which is initially at the nearer or open end of the U-shaped frame. The crank i8 is then turned to cause the eccentrics H, 28 to rotate in a counter-clockwise direction (as the parts are viewed in Figure '7) which in the illustrative machine will move about in. of the batt toward bar 34. The resistance offered by bar 351 to sliding of batt l6 over the table top forces the end of the batt to buckle and thus form the first corrugation, which is maintained between one of the straps 35 and bar 34. See Figure 12. The second corrugation is similarly formed and main tained, each complete turn of the crank causing the corrugating blade 3! to push forward about in., then lift clear of the batt and return to the initial position relative to the table, but farther along on the batt. See Fig. 13. This lifting takes place because of the engagement of arms 29, 36 with two needle bearings 36 each on a shaft (not shown) fixed to the corrugating end of the journal box supports and located immediately under said arms 29, 30. After the third corrugation is formed, the strap 35 nearest bar 34 is removed by hand and placed on the opposite side, and the corrugation which it held is maintained between bar 3 5 (and the corrugations adjacent bar 3 3) and the strap 35 which is now nearest bar 34, while the formed corrugated batting is retained under the glass plate 33. Thus each newly formed corrugation is held temporarily until moved under the glass plate by a succeeding corrugation. Bar 34 is pushed ahead of the corrugated batting and offers the requisite resistance to insure maintaining the corrugated shape of the batting until it is removed by lifting the glass plate. For each new corrugation a strap 35 is moved as described.
To soften the fibers and facilitate the operation, water was sprayed on the l-ply batting prior to the corrugating. After the drying operation, which immediately followed, the fibers retained the shapes in which they were formed by the machine. The same machine was used successfully in corrugating or pleating battings of acetate yarn and regenerated cellulose, and could be used on other textile battings including Webril and nylon. Webril is a cotton lint nonwoven fabric made by Kendall Mills, a division of The Kendall Company, Walpole, Massachusetts. However, when working with nylon a steam treatment with the temperature raised to a point exceeding the previous setting condition i necessary to insure retention of the corrugations.
Corragator having radially movable btades Referring to Figures 8 and 9, another type of corrugating machine is there shown, being sup ported on a table top d0 over which travels a batt M from the carding machine. Batt it may be multi-ply as described above, and the corrugating machine may be clamped on a plate which, in turn, is supported on the take-off conveyor of the carding machine, with the conveyor drive disconnected. This is not shown but will be readily understood. A horizontal shaft 42 is journaled in bearings 43 fixed upon the table top and may be turned by a crank l4 secured to one end, or by a motor and gearing, not shown. Fixed upon shaft 42 is a cylindrical roll 45 having radial equally spaced slots 46 extending throughout its length, eight slots being shown in the illustrative embodiment. Received in each slot is a rubber and metal blade 41 similar in characteristics to a windshield wiper blade; in fact, commercial windshield wiper blades have been used with good results. Springs (not shown) are carried inside the roll and are attached to each blade to tend to pull it inwardly or toward the axis of the roll, a tendency which is resisted by contact of the inner, metallic end of each blade with a fixed eccentric 48 which is loosely mounted on the shaft eccentrically thereto to act as a cam to force the blades outwardly as the shaft rotates the roll about the fixed eccentric. Now the outer flexible edges of the blades are about apart, measured circumferentially, when it is desired to form corrugations about in height; if higher or deeper corrugations are required, the spacing of the outer blade edges will be greater. A top plate 69, which in the laboratory was of Plexiglas but could be of metal or other material, is removably supported on the table top by means of a U-shaped frame 513 and is spaced about above the table top, in the illustrative apparatus. The end of plate 49 is beveled and set very close to the periphery of the roll to make certain that the web will pass under it and not be carried around with the roll. To prevent the blades il from striking the end of the plate, they are moved inwardly by the action of the cam and springs as described above. A follower-bar, similar to bar 34 (Figs. 7 and 12) may be used if it is desirable. to. offer: some additional; resistance to: movement of the corrugated batting over the table and under top. plate 49,.toxefiecttc'ompactinge of the corrugationsi Operation As the batt 41 is fed from the doffer (not shown) of the carding machine, with the shaft rotating counterclockwise as viewed in Figure 8, the batt is picked up. by thenearest blade and moved along under the machine.- The edge of the blade presses firmly: intothe batt. But when the blade is withdrawn in its slot, which occurs just beyond the lowest portion of the roll, the formed corrugation passes under the top'plate d9 where it isretained by friction until moved=along by the succeeding corrugations. The corrugated portion of the batt provides. the resistanceiwliich is essential to buckle the batt toform the individual corrugations. Initially, that isbefore there is a corrugatedbatt' end to provide the necessary resistance, a bar (not shown) isplaced on the forward end of the batt beyond the corrugator, and said bar is pushed along'untilit reaches the end of frame 50, whenit may be removed. For each revolution of theroll six inches (8 x of the batt is corrugated; hence, if the batt is fedto the corrugator at about 48 ft. per min, the roll must be rotated about 96 R. P. M; To prevent the fibers from adhering to. the blades. and/or slots it has been found desirable, and attimesnecessary, to vibrate the. roll end of the top plate 49 vertically through an arc of about: in. at a frequency of about 120 vibrations per minute. In the laboratory this has been accomplished by hand, but obviously several known mechanisms may be used to effect such-vibration. In lieu of a follower-bar, experiments show that a canvas (or similar rough-surfaced) belt fixed to the table top to serve as a fiat base plate and extending from the roll part way to the end of frame 51) will offer sufiicient frictional resistance to cause a wool batt to buckle and form corrugations without adherence to the blades and/or slots. This canvas belt will be understood without illustration.
The described elementary apparatus has worked perfectly on carded cotton, nylon. and wool, and doubtless will work on other textile battings, of natural, synthetic and semi-synthetic fibers and mixtures of such fibers.
Alternative corrumating method In studying the operation of a carding machine,
we have discovered that if the speed of the takeoff conveyer is reduced, the dofier comb builds up, a web which takes the shape of a corrugation. The periodic motion of the doffer comb'should be modified by shortening the distance through which the comb travels to-about %in.= (instead of its usual 1 in.) which increases its speed of vibration. With the take-01f conveyer speed reduced to approximately one-tenth the'peripheral speed of the doffer roll, corrugated battingsof the thickness required for' garment insulation in. corrugations) willbe formed from a single thickness web. For a double thickness web, the take-off conveyer speed might be one-fifth the peripheral speed of the dofier roll, with only half as many corrugationsto the linear foot of the batting; By condensing sucha corrugatedbatting between sets of parallel conveyer: belts, an increase in the density of the batting may be effected to almost any desired extent, since each set of belts maytravel. ata slower speed than 64 the preceding set; resulting=in1aalbngitudinal compacting of the corrugated batting.
Elastomers Softening and bonding witha concomitant fixation: of the corrugated structure have also been accomplished by. applying a. dilute aqueous dis" persion of an elastomer. Among; the elastomers which may be used are: polyisobutylene, polyisobutylene-diolefin synthetic rubber, polybutene, polychloroprene, polybutadiene, polybutadienestyrene synthetic rubber, polybutene-acrylonitrile synthetic rubber, polystyrene-isoprene synthetic rubber, natural rubber or latex, guttapercha, rubber hydrochloride, polyvinyl isobutyl ether, polyvinyl isopropyl ether, polyvinyl methyl ether, polyvinyl alcohol, polyvinyl acetate, polyvinyl butyral, polyvinyl chloride, polyvinyl chloride-vinylidene chloride copolymers, polyethylene, halogenated polyethylenes, polyalkylene sulfides, and silicones. In some instances, these elastomers may be sprayed on; in other cases they may be applied by immersion, for example.
In addition to adaptability to spraying, the elastomer should resist temperatures as low as 65 F., when the fabric is to be employed in the Arctic or Antarctic. One such elastomer is known as R33-F45 cement, a rubber-polybutadiene blend consisting of 25% solids in toluene, furnished by The Goodyear Tire &Rubber Co. The rubber from this cement should have several hours heating at around260 F. to develop cure. Faster curing cements are also available. Another suitable elastomer is Goodyears No. 7719-- 1310' latex, also a rubber-polybutadiene blend containing approximately 58% solids,, which re quires no particular vulcanization after drying, as it will develop maximum physical properties after a fewdays at room temperature.
Another elastomer suitable for deposition on wool is a positively charged (cationic) prevulcanized natural latex (Formula No. (NV-900) from General Latexv and Chemical Corporation, containing 20% total solids, with a pH of 6.8 to 7.2, and also containing an antioxidant. This material is saidv to be stable toward dilution and the addition of acids or alkalis, but is unstable when stored under a high alkalinity, hence dilute ammonia water is added just before use to bring it to the mildly alkaline conditions necessary for cationic latex to depositsuccessfully on protein fibers such-as Wool. For such depositing, the mostsatisfactoryrange is a pH of 8.5 to 9.5. The wool should be quite free of grease, salts or residual fixed alkali which might. react with the latex of Formula CW-900 to cause flocculation. The cationic latexcan be appliedby substantive deposition from a circulating bath of the latex, by saturation of the material to be treated with the latex bath, or by spraying. Under correct operating conditions, deposition of rubber from the CW-QOO is 100%, about 5% by weight of the final product being the rubber and being the wool fibers. Drying should be at a temperature of not over 70 C. and may be preceded by hydroextraction, once the latex particles have been deposited on the fibers. No cure is necessary as Formula CW-QOO is a prevulcanized latex. When an elastomer is zadded as described in this. and the two preceding. paragraphs, to the extent of only 5% or. thereabouts, the appearance of the woolbatt remains unchanged, but the" presence of the elastomer is usually apparent fromithefeel and theresponse ofthe batt to compression or. flexing;
Comparative tests A hand corrugated carded wool web of Albany Felt Wool F-l (8.7 oz. per sq. yd. before quilting or 13.3 oz. per sq. yd. including two facing fabrics of 1.6 and 3.0 02.) was compared with the same fibers formed as conventional laminated batting 8.7 oz. per sq. yd. and with double faced wool pile (20 oz. per sq. yd.) with the following results:
TABLE l-COMPRESSION RESISTANCE Thus, the corrugated sample tested greater resistance to compression and had 50% less quilted density (between 1.6 and 3.0 02. nylon facing fabric) than the double faced wool pile, which had no facing fabrics.
Data comparing compression resistance of ordinary wool batting, double face wool pile, wool top elastomer bonded, corrugated wool tops, and corrugated wool tops elastomer bonded are given in Table II. The experimental filling materials in each instance were prepared at the same weight (0.06 pound per sq. ft.) and were quilted with the same pattern between nylon facing fabrics having weights of 1.6 and 3.0 oz. per sq. yd.
8 dinarily formed flat batting (prepared from the same wool fiber used to make No. 1) received a rating of No. 8. These ratings take into account resistance to breakdown under shear compression and tensile forces. The ratings on all samples in the group of thirty (except two Fiberglass fabrics which displayed breakdown at 100 and 500 cycles) were based on compression measurements before and after 5000 cycles of flexing in a special testing machine. The white wool pile mentioned above and included in Table I, supra, is expensive and can only be made in limited quantities as few manufacturers have the facilities. Its density is 2.22 oz. per sq. ft., whereas the corrugated batting runs about 1 oz. per sq. ft. and if contained between two facing fabrics (respectively 0.18 oz. and 0.33 oz. per sq. ft.) still weighs only 1.51 oz. or less per sq. ft., a saving in weight of at least one-third.
Agraphical expression of the influence of batt structure on compression resistance is found in Figure 6, where two sets of stress-strain curves are shown, one for a laminated batt of Harriset wool, 50s before flexing and after 5,000 flexings, the other for a corrugated l-ply batt of the same fiber, before flexing and after 5,000 fiexings. As indicated, four readings were taken of the thickness of each fabric under four different pressures. The beneficial effect of the corrugated structure is apparent without comment.
In another comparison, batting consisting of eighteen wool webs (as defined above) laid flat one over the other was subjected to careful tests to determine heat transfer according to the wellknown formula lcAdT w a:
TABLE II.COMPP.ESSION RESISTANCE OF CORRUGATED AND ORDINARILY FORMED INSULATION BATTINGS Thickness (Inches) Under Load Original Quilted Bat- Quilted Batting After ting-Applied Prcs- 5,000 FlexiugsA.psure, pounds per plied Pressure, pounds square inch per square inch Harriset Wool, Tops (50s) 0.40 0.20 0.14 0.11 0.32 0.15 0.11 0.09 Percent of original thickness 100 50 35. 1 27. 6 80 37. 5 27. 6 22. 5 Harriset Wool, Tops (50s)l 0.57 0. 0.22 0. 17 0. 43 0.22 0. l5 0. l2 Elastomer bonded, percent of original thickness 100 61. 5 38. 6 29. 8 75. 5 38. 6 26.3 21.0 Corrugated Harriset Wool,
Tops (s) 0.45 0.32 0.24 0.18 0.38 0.22 0.17 0.14 Percent of original thickness 100 71.0 55. 5 40. 0 84. 5 49. 0 37. 8 31.1 Corrugated Harriset Wool,
Tops (50's) 0.43 0.31 0.23 0.17 0.34 0.20 0.15 0.11 Elastomer bonded, percent of original thickness 100 72.0 53. 5 .6 79.1 46. 5 34. 9 25.6 Double Face Wool Pile 0. 48 0.36 0. 26 0.20 0.35 0.26 0. 19 0.16 Percent of original thickness. 100 75 54. 2 41. 7 73.0 54. 2 39. 6 33. 3
The measurements on the pile fabr1c were made where k is a constant, dT is the change in temin the absence of facing fabrics and its weight was found to be 20 oz. per sq. yd. compared to the practically constant value of 13.3 oz. per sq. yd. for the quilted fabrics.
In a survey of thirty experimental and com mercial insulation battings, the laboratory-corrugated samples were found to be superior in compression resistance to all other fibrous battings. When listed in decreasing order of efficiency, based on compression resistance and weight per unit area, a corrugated wool mat made in accordance with the invention rated No. 1, a double-face white wool pile (the best fabric for insulation purposes heretofore known to the Deperature, A is the area, and cc is the thickness. For the 18-ply fiat batting. It was found to be 0.433.. Now a 4-ply corrugated web embodying the invention, formed at the same density (1 oz. per sq. ft.) may be three or four times as thick as the 18-p1y batting, because of the corrugations, hence by the above formula will have a much greater insulation value, and has a smaller constant. (k=0.408 for elastomer-bonded corrugated wool batting, but for plain corrugated wool batting k=0.390. These values were determined after 5,000 fiexings under a compression load of 0.01 p. s. i.)
Battings embodying the invention made from partment of the Army) rated No. 4; while an orcarded wool and an elastomer (latex) have withstood 20,000 flexings on a specially designed testing machine, without any sign of failure as viewed under transmitted light.
All the described corrugated battings may be and in some cases preferably are inclosed between two facing fabrics (such as cotton, rayon or nylon) of the same or different weights as seems desirable. Referring to Figures 4 and 5, a corrugated batting is sewed to facing fabrics 61, 02 by stitching t9 to form a quilt structure suitable for lining clothing, for batting and other uses, because of its light weight and high insulating value. If desired, the modifications to be described may also be quilted.
Modification with reinforcing filaments The addition to the web during the corrugating operation of continuous filaments of synthetic fibers running longitudinally of the web (which may be easily done by guiding the filaments to the corrugating zone of either type of machine described above), may considerably increase resistance to compression. Thus, nylon monofilaments of 30 or 45 denier may be spaced about one-fourth or one-half inch across the web and corrugated and set therewith (if desired, under elevated temperatures) to improve compression resistance without significantly affecting the drape. Mono-filaments of Saran (Dow Chemical Co.) which is a vinylidene chloride derivative, Orion (Du Pont) which is made from polyacrylonitrile, Vinyon (Carbide and Carbon Chemicals Corporation) which is vinyl chloridevinyl acetate ccpolymer, Dynel (Carbide and Carbon Chemicals Corporation) which is a vinyl chloride acrylonitrile copolymer, and Dacron (Du Pont) or polyglycol terephthalate, may be used in lieu of nylon and will likewise improve the strength of the web. Figure 10 is a schematic diagram of this modification of the process, While Figure 11 is a fragmentary perspective of the product of that modified process, shown di agrammatically as it is impossible to illustrate the individual fibers of the carded web.
Modified batting having cushioning characteristics When a corrugated batting of several wool webs (as defined above), is subjected to a bath of latex or similar elastomer under the proper conditions about of the latex will unite with the fibers to form a modified batting which is highly resilient and extremely porous, is black and wool-like in appearance but of a rubbery feel, necessarily is a good heat-insulator, and drapes difierently from the white wool pile or the corrugated Harriset wool, 50s, with or without latex, described above. This modified batting is further characterized by being readily stretchable in the direction of its length (the direction its fibers extend), but scarcely at all in a transverse direction, hence may be termed uni-lastic,"
that is elastic unilaterally. The resiliency of the corrugations is so great that when a compression load is imposed and then released they will spring back like pure sponge rubber. The density of this material may be about 0.33 pound per sq. ft. with an over-all thickness of 1.08 in. under 0.01 p. s. 1. pressure. Koylon, a U. S. Rubber Co. sponge rubber product, with the same density and under the same pressure has an over-all thickness of 0.394 in. Under a pressure of 2 p. s. i., the corrugated material has a thickness of 0.394 in. compared with the 0.303 for the Koylon. With the pressure increased to 10 p. s. i., the corrugated product is 0.18 in. thick, the Koylon 0.12 in. thick. This suggests that this novel fabric will find a wide field of use wherever a light weight cushioning pad is desirable, ior example, in chair pads, cushions, upholstery, etc., in crash helmets, football helmets, etc., in airplane interiors etc. Obviously, the material has sound-deadening, as well as heatinsulating qualities, and because of its porosity, it will breathe.
From the foregoing, the value of the invention will be apparent without further discussion.
Having described our invention, what we claim as new and desire to secure by Letters Patent is:
A fibrous porous non-woven fabric corrugated throughout substantially its entire area, with the corrugations set and brought close together but free of attachment to each other, and continuous mono-filaments of synthetic resinous material extending longitudinally of and over the surface of the web and transversely of the corrugations, said mono-filaments being corrugated with said web, and with said surfaces in side-by-side relationship, and said mono-filaments being spaced apart transversely of the web, to improve its compression resistance without afiecting the drape.
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