US3154462A

US3154462A - Non-woven fabric and process of making same

Info

Publication number: US3154462A
Application number: US142948A
Authority: US
Inventors: Ii Alexander M Smith
Original assignee: Fiberwoven Corp
Current assignee: Fiberwoven Corp
Priority date: 1961-10-04
Filing date: 1961-10-04
Publication date: 1964-10-27
Anticipated expiration: 1981-10-27
Also published as: NL283925A; FR1335397A; NO283925L; DE1282980B; NL130447C; GB946857A

Description

Oct. 27, 1964 A. M. sMrrH n 3,154,462

NON-WOVEN FABRIC AND PROCESS 0F MAKING SAME Filed Oct. 4, 1961 2 Sheets-Sheet 1 5ff55-5z69/A/ fue l/fs ATTORNEYS ct. 27, 1964 A. M. SMITH u 3,154,462

NoN-WOVEN FABRIC AND PROCESS oF MAKING SAME med oct. 4, 1961 2 sheets-sneer 2 ATTORNEYS United States Patent 01 3,154,462 NUN-WVIEN FABRIC PRUCESS GE MAKEJG SAME Alexander M. Smith H, Elkin, N.C., assigner, by mesne assignments, to The Fiherwoven Corporation, Elkin,

N .11, a corporation of North Carolina Filed Urt. 4, 1961, Ser. No. 142,945 22 Claims. (Cl. 161-154) The present invention relates to non-Woven fabric structures and, more particularly, to an improved process of making a non-woven fabric structure by needling loosely matted fibers of webs to a foundation of warp yarn or threads or a scrim having warp yarn or threads and then stretching and setting the warp of the foundation.

Non-woven fabric structures heretofore made have derived their strength by bonding the entangled fibers through use of suitable bonding agents or by a shrinking process Where some synthetic fibers having heatshrinking or solvent-shrinking properties are utilized. In the non-woven unbonded fabric structures, strength has been derived solely from the inner fiber entanglement and frictional forces of the entangled fibers. An improved process of making non-woven unbonded fabric structures is disclosed in my copending application Serial No. 29,115, filed May 13, 1960, now U.S. Patent No. 3,090,099, and entitled Needle Punch Machine and Method, as well as in my copending application Serial No. 31,910, filed May 26, 1960, now U.S. Patent No. 3,090,100, and entitled Needle Punch Machine and Method. In the aforementioned copending applications, the producing of a non-woven fabric by an improved method of needling is disclosed, the improved method of needling web or webs of loosely matted fibers resulting in a controlled interlooping and interlacing of the fibers to provide a product having strong fiber entanglement regardless of whether the fibers are natural or synthetic, a high density, and uniform napping properties on either side thereof.

The present invention is a further improvement in a process for making non-woven fabric structures in that it provides for increased overall strength in the resulting product by utilizing the strength obtained from fiber entanglement to reinforce the scrim or warp yarn or thread strength. Therefore, an important object of the present invention is to provide an improved method of manufacturing a non-woven fabric from at least two webs or batts of loosely matted fiber having a foundation of a scrim or warp sandwiched therebetween prior to needling, the product after needling being subsequently treated to reinforce the strength of the foundation.

Another object of the present invention is to provide an improved process for making a non-woven needled fabric wherein an increased needle loom production is accomplished.

A further object of the present invention is to provide an improved process for making a non-woven structure wherein the webs prior to needling may be thicker for a given thickness of the final product, thus, resulting in the most advantageous needling operation.

Ancillary to the preceding object, it is still another object of the present invention to provide an improved process of making a non-woven fabric such as a blanket or the like, the resulting fabric having a softer hand and better napping characteristics.

Still another object of the present invention is to provide an improved process of making a non-woven fabric from webs or batts of cross-laid fibers having a foundation of a scrim or Warp interposed therebetween, the process contemplating stretching and permanently setting the scrirn or warp in a warp-wise direction whereby the needled fibers are partially reoriented in a warp-wise direction and will not slip on the threads or yarn of the warp or scrim.

Ancillary to the preceding object, a further important object of the present invention is to provide a process of making a non-woven fabric which has less warp-Wise stretch than heretofore realized, the strength peak caused by fiber entanglement being reached prior to the strength peak of the scrim or warp whereby the strength of the liber entanglement reinforces the scrim or warp strength.

Another object of the present invention is to produce a non-Woven fabric structure having strength in the elongation range comparable to the range of strength of a woven fabric.

rThese and other objects and advantages of the present invention will appear more fully in the following specification, claims and drawings in which:

FIGURE 1 is a stress-strain graph illustrating the comparative curves on a non-Woven fabric structure tested after needling and of the same non-woven fabric structure tested after needling and stretching according to the present invention;

FIGURE 2 is a side elevational view diagrammatically illustrating a system for producing a non-woven fabric structure according to the present invention;

FIGURE 3 is a side elevational view diagrammatically illustrating a modified system for producing a non-woven fabric according to the invention;

FIGURE 4 is a side elevational view diagrammatically illustrating still another modified system for producing a non-woven fabric structure according to the present in- Vention;

FIGURE 5 and FIGURE 6 are schematic representations of a piece of non-woven fabric after needling and after stretching, respectively, and illustrating the increased production of a given needle loom by utilization of the process of the present invention.

Referring now to the drawings wherein like character and reference numerals represent like or similar parts and, in particular, to FIGURE 2, the process of the present invention broadly contemplates sandwiching a foundation, generally indicated at 10, between two or more Webs or

batts

12 and 14 of loosely matted fibers, then passing the webs and the interposed foundation through a needle loom 16 wherein the loosely matted fibers of the

webs

12 and 14 are reoriented into interlooping and interlacing entanglement with one another. After the needling operation is performed by the needle loom 16, the resultant needled product passes through a first pair of feed rollers 18 and a second pair of feed rollers 20 where the resulting needled fabric is `stretched and the `stretched foundation of the same is set in a warp-wise direction, as will be explained in more detail later in the specification.

It will be understood the webs or

batts

12 and 14 may be continuously fed from conventional carding machines where the fibers are carded and loosely formed into the webs, or the webs may -be supplied from rolls of such material after the material has been taken from such carding machines and formed into rolls. Preferably, the webs or

batts

12 and 14 have a majority of their loosely matted fibers cross-laid with respect to the direction of feed of the webs through the needle loom 16 and rollers 1S. The carding of the

webs

12 and 14 resuits in the fibers being generally oriented parallel with respect to the longitudinal axis of the web and then the web may be shingle folded so that when it is fed as a web through the needle loom, the fibers extend generally cross-wise to the direction of feed.

The needle loom 16 includes opposed sets or banks of needles arranged to alternately penetrate the opposite surfaces of the

webs

12 and 14 as they are advanced with the foundation therebetween. The needle loom 16 which provides for the positive interfiber entanglement of the loosely matted fibers of the

webs

12 and 14 through the foundation 10 may be of the type disclosed in my copending United States application Serial No. 29,115 and application Serial No. 31,910, and the needling process may be similar to the needling process also disclosed in the aforementioned applications. To the extent of the disclosures of the needle looms and needling processes, the subject matter disclosed in the aforementioned applications is incorporated by reference into this application.

The fibers of

ythe webs

12 and 14 may be synthetic fibers such as rayon, nylon, Acrilan, Orlon or the like, or natural fibers such as wool, cotton or the like. Also the webs may be made up of blend of different synthetic fibers or different natural fibers or blends of both.

The foundation 10, as previously mentioned, may be Y either a scrim, which is a loosely woven fabric usually made from warp and weft of yarns or threads or it may be merely warp of yarns or threads suitably spaced width-wise of the webs. However, an important characteristic of the foundation is that the yarns or threads of the scrirn or the warp, as the case may be, must be elastic to the extent that they can be stretched and set to the length stretched. The warp of the foundation may be spun from synthetic slivers or rovings and can be either plasticized `by heat or by suitable solvents or by a combination of heat and suitable solvents so that they can be stretched and permanently set for temperature and conditions of intended use of the end product.

FIGURE 2, as mentioned hereinbefore, discloses a typical system for accomplishing the present invention when the foundation 10 is made from threads such as polypropylene, nylon or the like which may be plasticized by heat. For example, the

webs

12 and 14 are made up 0f loosely matted fibers of rayon whereas the foundation 10 may either be a serim or warp of polypropylene. After the sandwich construction of the two

webs

12 and 14 with the foundation 10 interposed therebetween passes through the needle loom 16 where the cross-laid rayon iibers of the

webs

12 and 14 are oriented into cohering fiber entanglement and between the feed rollers 1S, the resultant needled product is subjected to heat by any suitable source of heat 22. Since the scrim or warp in the particular example being described are made from polypropylene, it has been found that a temperature in the order of 300 F. is necessary to plasticize the polypropylene threads sufciently to permit an elongation of the warp in a warp-wise direction. Rollers are operated at a faster speed than the rollers 18 so as to apply a tension to and elongate the fabric structure between

rollers

18 and 20 after it has been heated. Suflcient tension is applied to the fabric structure so that when the warp of the foundation has been plasticized, it will elongate or stretch to a length approximately 40% greater than its original length. The warp of the foundation 10 is maintained in the stretched position a sufficient length of time to allow for cooling and permanent setting of the same.

By lstretching the non-woven needled fabric structure to a length 40% greater than its original length, there is an accompanying side-wise contraction but it has been found that this side-wise contraction is only approximately 10% of the original width of the non-woven needled fabric. Consequently, an approximate 30% gain in area is obtained from a given needle loom. With such a gain, the

webs

12 and 14 can be thicker and more dense to start with and thus result in more advantageous needling conditions as better interlooping and interlacing of iibers occurs in thicker webs.

Referring now to FIGURE 1, a graph or chart of stress-strain profile showing comparative tests on identical needled fabrics is disclosed. The broken line curve identified by the numeral 24 represents rayon fiber webs needled on a foundation of polypropylene warp threads without the subsequent stretching operation. As needled, the fabric represented by the broken line 24 had a weight of 9.2 ounces per square yard. It will be noted that the curve 24 has two peaks designated A and B, respectively. The peak A indicates the point of failure of the warp threads and shows that such failure occurs at an approximate pulling force of 24 pounds with an accompanying elongation of approximately 40% of the original length of fabric being tested. To the right of point A, there is a drop off in the pulling force as the material is further elongated until such time that the fiber entanglement takes over to provide the strength necessary to require additional pulling force for additional elongation. At peak B, the maximum pulling force or peak strength of fiber entanglement is reached and from that point on there is failure of the strength of the fiber entanglement.

The solid line curve of the chart shown in FIGURE 1 and identified by the numeral 26 represents a stress-strain profile of the same non-woven needled fabric as the stressstrain prole curve 24 except that the fabric has been subsequently treated by stretching and permanently setting the warp threads to a length 40% greater than their original length. After the warp threads of the test piece of fabric has been stretched at 300 F. to a length approximately 40% greater than their original length and permanently set at this length, the weight of the fabric was 6.9 ounces per square yard. When testing the stretched nonwoven fabric made of rayon liber webs needled on polypropylene warp threads, the stress-strain profile 26 reached a peak strength C when approximately 29 pounds of force was applied, the resulting elongation only being about 22% of the original length of the fabric. After point C, the curve drops off but then flattens out until it reaches a second drop ofipoint D at an elongation of approximately 60% of its orginal length. It will be noted that between O and 60% of warp-wise elongation, the needled fabric treated by permanently stretching the warp threads after needling can withstand considerably more pulling Vforce than the needled fabric which had no stretching even though the warp threads and the total product tested was lighter in weight. An important feature of the comparative stress-

strain curves

24 and 26 is that considerably more pounds of pulling force can be exerted on a stretched and permanently set non-woven needled fabric, as shown by the stress-strain profile curve 26, up to the point C without too much elongation. By comparison, the non-woven needled fabric which has not been stretched and which is represented by the stress-strain profile 24 elongates more rapidly and greater for less pounds of pulling force. In other words, in the area where the `.strength of fabric structure is needed without too much elongation of that fabric structure, it is obtained by the non-woven needled fabric which has its warp threads stretched and permanently set at a length approximately 40% greater than its original length. It should be noted that the stretched fabric provides strength of entangled fibers and warp threads in the elongation range normally associated with woven fabrics.

Another important feature of the comparative stressstrain curves 24 and 26 is that the fiber entanglement peak is moved from B in graph 24 to D in graph 26. This teaches that the liber entanglement is less loosely attached to the yarns or threads of the warp or scrim, and this is important in subsequent finishing operation on the fabric such as napping and the like.

The above tests which resulted in the graph shown in FIGURE 1 were obtained on a Thwing-Albert strength tester on one-inch strips of fabric, jaws at 3 inches and speed at 12 inches per minute.

Referring now to FIGURE 5, a piece of non-woven fabric which has been needled but has not been subsequently stretched is shown in plan profile. The length of the fabric is represented by Y whereas the width of the fabric is represented by X. The area of the fabric in FIGURE 5 is XY. FIGURE 6, on the other hand, represents the same piece of fabric after it has been subjected to a Warp-wise elongation so as to stretch the warp threads and permanently set the same to length 40% greater than the original length. It will be noted in FIGURE 6 that the length of the piece of fabric is (YA-40% Y) whereas the width is (If-10% X). The resulting area of the piece of fabric of FIGURE 6 is (X-10% X) (Yl-40% Y). When the fabric of FIG- URE 5 is stretched warp-wise to a length 40% greater than its orginal length and there is a corresponding approximately 10% width-wise contraction, the area increase of the fabric of FIGURE 6 is approximately 30%. Consequently, for a given needle loom utilizing the process of the present invention, an increase in production results. Of course, it will be understood that thicker webs 12 and I4 may be originally used with this process and thus better fiber entanglement is obtained in the resulting thinner or light weight non-woven fabric structures. The utilizing of thicker webs at the outset results in a fabric structure having a softer hand and far superior napping characteristics without damage to the sub-surface entanglement of fibers.

FIGURE 3 is a View similar to FIGURE 2 but showing a modified system for accomplishing the process of the present invention. In FIGURE 3, the non-woven needled fabric issuing from the needle loom 16 passes through the feed rollers 18 and between the

rollers

28 and 30 into a tank 32 having a suitable solvent for plasticizing warp of the foundation l0. In such a system, the warp of the foundation 10 may be made from nylon, cellulose acetate, acrylic fibers, polyethylene fibers or irradiated polyethylene, polyester fibers, e.g., Daeron or the like, such material being capable of being plasticized by solvents and/ or heat. After the warp of the foundation 10 has been plasticized by immer-sing the entire needled non-woven fabric in the tank 32, the fabric then passes through the rollers 20 which `are operating at a faster speed than the rollers 13 so that suitable tension is applied to the fabric to give the warp the desired elongation, it being understood that the tension is applied for a sufiicient time to permit the warp of the foundation to permanently set by cooling or removal of solvent.

When heat is used, the tank 32 is closed by a suitable cover jacket 33 and may be suitably sealed for pressure operation. In some cases, the plasticizer may be hot water or steam.

FIGURE 4 is a still further modification of the system for accomplishing the present invention. In FIGURE 4, the needled non-waven fabric after passing from the needle loom 16 passes through the rollers 1S and beneath one or more spray nozzles 34 which spray a solvent onto the fabric to plasticize the foundation l0. Excess solvent may be collected in a tank 36 positioned below the nozzles and reused. After the solvent has been sprayed onto the fabric so as to plasticize the foundation 1li), the fabric passes through the rollers 20 which operate at a speed greater than the speed of the rollers 18 so as to `apply the necessary tension to the fabric to elongate and permanently set vthe warp yarns of the foundation l0 by removal of solvents.

It will be under-stood that the plasticizer should be selected for lthe warp or scrim, the plasticizers not adversely `affecting the fibers of the webs.

The processof the present invention as heretofore described produces a non-woven fabric vstructure especially adaptable for making blankets and the like having strength characteristics substantially the same .as prior woven fabrics. It will now be evident the described process produces a non-woven fabric structure in which the strength obtained from fiber entanglement is utilized to reinforce the strength of the scrim or warp. When the scrim or warp is stretched and permanently set, it also causes the entire fabric structure to elongate, thus, re-

orienting some of the previously oriented fibers in a warpwise direction. In fact, non-woven fabrics may be made from lthe present process wherein warp alone is utilized rather than a scrim. In addition, the process produces a non-'woven fabric in which the needled fibers do not have a tendency to slip on the warp when tension is applied to the fabric structure. A gain in production of a given needle loom is obtained by the process of the present invention as well as an .advantageous needling condition because thicker webs of loosely matted fibers may be used. The resulting fabric structure has .a softer hand and better napping characteristics.

The terms Warp as used in the claims is intended to cover filaments or long fibers or fibers spun into a yarn or threads of a scrim extending in a warp-wise direction as well as a foundation having only filaments, threads or yarn extending in a warp-wise direction.

While the invention has been described in its preferred embodiments, various changes may be made without departing from the spirit and scope of the invention. Therefore, the terminology used in the specification is for the purpose of description and not limitation, the scope of the invention being dened in the claims.

What is claimed is:

1. A process for making a non-woven fabric structure comprising the steps of: forming webs of loosely matted fibers; interposing a foundation of at least a stretchable and settable warp between the webs of loosely matted fibers; needling the webs of loosely matted fibers so that the fibers of each web are oriented between individual Warp of the foundation and into cohering entanglement with each other and with the warp of the foundation to form a needled fabric; then subjecting said needled fabric to longitudinal tension to stretch the warp of the foundation of the same; reorienting at least some of the needled fibers of the Webs in a warp-wise direction when stretching only the warp of the foundation; and permanently setting only the warp of the foundation while in its stretched condition whereby the reorienting in La warp-wise direction of the entangled needled fibers results in a shifting of the tensile strength peak of the needled fibers to a point wherein the strength of fiber entanglement of the webs reenforces the tensile strength peak `of the permanently stretched warp to thereby increase the tensile strength of the fabric structure.

2. A process for making a non-woven fabric structure comprising the steps of: forming webs of loosely matted fibers having a majority of the fibers laid generally crosswise of the webs; interposing a foundation of at least a stretchable and permanently settable warp between the webs of loosely matted cross-laid fibers; needling the webs of loosely matted cross-laid fibers so that the fibers of each web are oriented between the individual warp of the foundation and into cohering entanglement with each other and with the warp of the foundation to form a needled fabric; then subjecting said needled fabric to longitudinal tension to stretch the warp of the foundation of the same; reorienting at least some of the needled fibers' of the webs in a warp-wise direction when stretching only the warp of the foundation; and holding the stretched warp of the foundation for a sufficient length of time to permanently set only the warp whereby the reorienting in a warp-wise direction of the entangled needled fibers results in a shifting of the tensile strength peak of the needled fibers to a point wherein the strength of fiber entanglement of the webs reinforces the tensile strength peak of the permanently stretched warp to thereby increase the tensile strength of the fabric structure.

3. The process of claim 2 wherein the stretching of the needled fabric is in the order of 40% of the original length of the same.

4. A process for making a non-woven fabric structure comprising the steps of: forming Webs of loosely matted cross-laid fabrics; interposing a foundation of at least stretchable and settable synthetic warp between the webs of loosely matted cross-laid fibers; needling the webs'of loosely matted cross-laid fibers so that the fibers of each web are oriented between the individual webs of the foundation and into cohering entanglement with each other and with the warp of the foundation to form a needled fabric; subjecting the needled fabric to heat while applying a tension to only the warp of the foundation to thereby stretch the same; reorienting at least some of the needled fibers of the webs in a warp-wise direction while only the warp of the foundation is being stretched; and permanently setting the warp of the foundation while in its stretched condition whereby the reorienting in a warpwise direction of the entangled needled fibers results in a shifting of the tensile strength peak of the needled fibers to a point wherein the strength of fiber entanglement of the webs reinforces the tensile strength peak of the permanently stretched warp to thereby increase the tensile strength of the fabric structure.

5. The process of claim 4 wherein the warp is threads of polypropylene and wherein the heat is applied at a temperature in the order of 300 F.

6. The process of claim 4 wherein the warp is nylon.

7. The process of claim 4 wherein the loosely matted fibers of the Webs are rayon and wherein the warp is' polypropylene.

8. The process of claim 4 wherein the loosely matted fibers of the webs are rayon and wherein the warp is nylon. Y

9. The process of claim 4 wherein the warp is an acrylic.

10. A process for making a non-woven fabric structure comprising the steps of: forming webs of loosely matted predominantly cross laid fibers; interposing a foundation of stretchable and settable synthetic warp between the webs of loosely matted fibers; needling the webs of loosely matted fibers so that the fibers of each web are oriented between individual warp of the foundation and into chering entanglement with each other with the warp of tion of the needled fabric; then subjecting said needled fabric; plasticizing only the synthetic warp of the foundation of the needled fabric; then subjecting said needled fabric to longitudinal tension to stretch the warp and simultaneously reorient some of the previously-oriented fibers in a warpwise direction; permanently setting the stretched plasticized warp whereby the reorienting and slippage of the entangled fibers in a warpwise direction over each other and the warp increases length stability and the strength of the needled fabric; and then napping the outer surfaces of the resulting fabric structure without disturbing the sub-surface entanglement of fibers and the fibers reoriented in a warpwise direction.

11. A process for making non-woven fabric structure comprising the steps of: forming webs of loosely matted fibers; interposing a foundation of stretchable and settable warp between the webs of loosely matted fibers; needling the webs of loosely matted fibers so that the fibers of each web are oriented between the individual warp of the foundation and into cohering entanglement with each other and with the Warp of the foundation to form a needled fabric; plasticizing the warp of the foundation; applying tension to only the warp of the foundation of the needled fabric while the warp is plasticized to stretch the same and reorient some of the entangled fibers of the webs in a warp-wise direction; maintaining tension on the warp of the foundation until the warp is permanently set whereby the reorienting in a warp-wise direction of the entangled needled fibers results in a shifting of the tensile strength peak of the needled fibers to a point where the strength of fiber entanglement of the webs reinforces the tensile strength peak of the permanently stretched warp to thereby increase the tensile strength of the fabric structure.

12. The process of claim 11 wherein plasticizing of the warp of the foundation is accomplished by immersing the needled fabric in a plasticizing solvent.

13. The process of claim 11 wherein plasticizing of the Warp of the foundation is accomplished by spraying the needled fabric with a plasticizing solvent.

14. The process of claim 11 wherein plasticizing of the warp of the foundation is accomplished by simultaneously heating and immersing the needled fabric in a plasticizing solvent.

l5. The process of claim 11 wherein plasticizing of the warp of the foundation is accomplished by heat.

16. The process of claim 11 wherein the needled fabric is stretched and permanently set in the order of 40% of the original length of the same.

17. A needled non-woven fabric structure comprising: a foundation having at least a warp made from synthetic material which has characteristics of being stretchable and permanently set at temperatures and conditions of intended use of the needled fabric structure, at least two layers of needled fibers, said foundation being sandwiched between said layers and the fibers of said layers being oriented between the individual warp of the foundation and into cohering fiber entanglement with each other and with the warp of said foundation, the warp of said foundation being stretched and permanently set with at least some of the fibers of said layers being further oriented in a warp-wise direction by the stretched warp of the foundation whereby the reorienting in a warp-wise direction of the entangled needled fibers results in a shifting of the tensile strength peak of the needled fibers to a point wherein the strength of entanglement of fibers reinforces the tensile strength peak of the permanent set warp to thereby increase the tensile strength of the fabric structure.

18. The non-woven fabric of claim 17 in which said warp of said foundation is polypropylene.

19. The non-woven fabric structure of claim 18 wherein said foundation is stretched and set in a warp-wise direction approximately 40% of its length.

20. The non-woven fabric structure of claim 17 in which the warp of said foundation is an acrylic.

21. The non-woven fabric structure of claim 17 in which the warp of said foundation is nylon.

22. The non-woven fabric structure of claim 17 in which the fibers of said plurality of layersl are predominantly cross laid prior to being oriented between the individual warp of the foundation and into cohering fiber entanglement with each other and with the warp of said foundation.

References Cited in the file of this patent UNITED STATES PATENTS 2,588,228 Gates Mar. 4, 1952 2,943,379 Foltz July 5, 1960 3,090,101 Chagnon et al May 21, 1963 FOREIGN PATENTS 801,439 Great Britain Sept. 17, 1958 801,440 Great Britain Sept. 17, 1958 UNITED STATES PATENT oEETCE CERTIFICATE GF CORRECHN Patent No 3 ,154 ,462 October 2 7 1964 Alexander M. Smith I1 I It is certified Jchat error appears in the above identified patent and that Said Letters Patent are hereby corrected as Shown below:

Column 7, line 59, "tion of the" should read the foundation interposed therebetween to Jform a same 1ine 39, cancel "then subjecting said needled line 40, cancel "fabricg Signed and Sealed this 27th day of January 1970.

(SEAL) Attest:

Edward M. Fletcher, Jr. WILLAM SCHUYLER,

Attesting Ufficer Commissioner of Patents

Claims

1. A NEEDLED NON-WOVEN FABRIC STRUCTURE COMPRISING: A FOUNDATION HAVING AT LEAST A WARP MADE FROM SYNTHETIC MATERIAL WHICH HAS CHARACTERISTICS OF BEING STRETCHABLE AND PERMANENTLY SET AT TEMPERATURES AND CONDITIONS OF INTENDED USE OF THE NEEDED FABRIC STRUCTURE, AT LEAST TWO LAYER OF NEEDLED FIBERS, SAID FOUNDATION BEING SANDWICHED BETWEEN SAID LAYERS AND THE FIBERS OF SAID LAYERS BEING ORIENTED BETWEEN THE INDIVIDUAL WARP OF THE FOUNDATION AND INTO COHERING FIBER ENTANGLEMENT WITH EACH OTHER AND WITH THE WARP OF SAID FOUNDATION, THE WARP OF SAID FOUNDATION BEING STRETCHED AND PERMANENTLY SET WITH AT LEAST SOME OF THE FIBERS OF SAID LAYERS BEING FURTHER ORIENTED IN A WARP-WISE DIRECTION BY THE STRETCHED WARP OF THE FOUNDATION WHEREBY THE REORIENTING IN A WARP-WISE DIRECTION OF THE ENTANGLED NEEDLED FIBERS RESULTS IN A SHIFTING OF THE TENSILE STRENGTH PEAK OF THE NEEDLED FIBERS TO A POINT WHEREIN THE STRENGTH OF ENTANGLEMENT OF FIBERS REINFORCES THE TENSILE STRENGTH PEAK OF THE PERMANENT SET WARP TO THEREBY INCREASE THE TENSILE STRENGTH OF THE FABRIC STRUCTURE.