TEXTURIZED FABRICS

Abstract: Disclosed are loosely woven fabrics formed of multi-filament texturized synthetic warp and filling yarns, wherein the filaments of at least one of the multi-filament texturized synthetic warp and filling yarns are tacked at predetermined intervals. These loosely woven fabrics have a variety of uses including but not limited to as substrates for adhesive tapes, fabrics impregnated with wax and other finishes, wall coverings, and laminated fabrics.

Description: TEXTURIZED FABRICS FIELD OF THE INVENTION The present invention is directed to loosely woven fabrics formed of multi-filament texturized synthetic warp and filling yarns, wherein the filaments of at least one of the multi-filament texturized synthetic warp and filling yarns is tacked at predetermined intervals and the use of such fabrics as substrates for a variety of products. BACKGROUND OF THE INVENTION Loosely woven fabrics have many uses, for example, as substrates or reinforcing fabrics for a variety of end products including adhesive tapes, such as duct tape, athletic tapes, medical tapes, auto-harness wrap tape, and so forth; fabrics impregnated with wax and other finishes, such as tack cloths, bone wrap, ammunition wrap, and so forth; wall coverings used in home and industrial wall decorations; and laminated fabrics used in clothing, shoes, and furniture. Gauzes are one type of loosely woven, open- mesh fabric which are particularly useful as substrates for various adhesive tapes. Open-mesh knit fabrics can also be used as substrates for adhesive tapes. However, where cost is an issue, woven fabrics are preferred because they are less costly to make than knits. The strength, cost and tearability in use are all properties that are taken into consideration when selecting a substrate or reinforcing fabric for an adhesive tape and the fibers used in constructing the substrate or reinforcing fabric for such tapes will affect all of these properties. Although gauzes are conventionally prepared from a spun cotton or cotton /synthetic blended yarn, the use of multi-filament synthetic yarns in the manufacture of gauze fabric is highly desirable because of the strength and cost savings advantages provided by such synthetic yarns over spun yarns. In the case of gauze substrates for adhesive tapes, the use of synthetic yarns would provide gauze having lower yarn count yet adequate strength and tearability. However, because of the natural slickness of synthetic yarns, it has been difficult to prevent fabric weave distortion, and in particular in the low count constructions of gauze fabrics. In the case of gauze used as a duct tape substrate, fabric constructions and yarn counts with traditional spun yarns have reached the lower limits while providing adequate properties, leaving limited opportunities for further cost reductions. Conventional low end woven duct tape fabric has a construction of 18 x 8 and uses a spun cotton or polyester/ cotton blended yarn in both warp and filling, the yarn counts generally being in the 30/ 1 to 40/ 1 range of cotton count. Spun yarn counts lower than 40/ 1 become too low in strength and/or too expensive for use in duct tape product lines. Fabric constructions such as 18 x 8 and lower, often perform poorly through the tape making process because of low fabric strength. Furthermore, the tape has poor appearance and poor tear characteristics. Gauze fabrics including synthetic fibers are known in the art. For example, U.S. Patent No. 4,303,724 disclosed duct tape incorporating a gauze substrate woven of texturized or false-twist yarns in the filling direction which are continuous filament yarns which have been given increased bulk and loft by the introduction of numerous loops, curls and coil. Texturized yarns perform more like conventional spun yarns. Gauze substrates also incorporating texturized yarns for use in making vinyl products are disclosed in U.S. Patent Nos. 4,935,293 and 5,043,208. Adhesive tape substrates are disclosed in U.S. Patent No. 4,654,254 wherein the substrate is a gauze fabric of cotton warp yarn and textured polyester filler yarns. Texturized yarn is sometimes referred to herein as textured yarn. U.S. Patent No. 4,304,813 disclosed warp knit, weft inserted all synthetic continuous filament yarn fabric, preferably polyester, as a substrate for a pressure sensitive adhesive. Even though knit construction provides greater stability when using slick synthetic fibers, a woven construction is less expensive than knit and, thus, highly desirable. U.S. Patent No. 4,439,482 disclosed a base fabric for adhesive tapes in which a multi-filament yarn without twists, i.e., a flat yarn, of polyester fibers having a specific residue in molecular chain was used as the warp. U.S. Patent No. 5,047,285 disclosed a 100% polyester fabric for use as base fabric for tapes wherein a preferably continuous filament, warp yarn carries a non-hardening agglutinating sizing. Related U.S. Patent No. 5,279,891 disclosed a woven tape support fabric comprising ribbonized warp yarn processed with agglutinating resin sizing to a specified add-on content. U S Patent Nos 4,874,019 and 4,925,726 disclose wall covering substrates formed of texturized, continuous multi-filament yarns having hydrophilic characteristics Gauze fabπcs comprising synthetic yarns which do not involve preparatory procedures such as sizing to achieve lower costs and greater efficiency are being sought SUMMARY OF THE INVENTION It has unexpectedly been found that distortion problems are encountered when producing loosely woven fabπcs comprising multi- filament texturized synthetic yarns m both the warp and filling directions and that these problems can be overcome without resorting to a preparatory procedure such as sizing by using as the warp yarn, the filling yarn or both a multi filament texturized synthetic yarn which is tacked at predetermined intervals In other words, the warp yarn, the filling yarn, or both used in these fabrics have not only been put through a texturing process, they have also been tacked to provide filament entanglements at varying levels up to about 90 to about 100 tacks per meter The tacking provides improved resistance to filament separation in the multi filament texturized synthetic yarn, thus, resulting in better weaving performance, construction stability and fabric quality The tacking of the filaments of the multi filament texturized synthetic yarn at predetermined intervals provides sufficient stability to produce superior loosely woven fabncs in the low count gauze fabric constructions without appreciable distortion Furthermore, the use of such synthetic yarns results in cost savings due to the ability to use lower constructions while minimizing compromise in strength DESCRIPTION OF THE INVENTION The present invention provides a loosely woven fabric which compnses multi- filament texturized synthetic warp and filling yarns, wherein the filaments of the multi-filament synthetic yarn are tacked at predetermined intervals in one or both of the warp and filling directions In embodiments wherein only one yarn is tacked, it is preferred that the filling yarn is tacked In preferred embodiments, both the filling and warp yarns comprise multi-filament texturized synthetic yarn tacked at predetermined intervals It was unexpectedly found that tacked multifilament texturized synthetic yarns for use in -he loosely woven fabrics of the present invention have sufficient stability to be used unsized as warp yarn. The quality of the tacks is adequate if they remain essentially intact during the particular weaving process. The stability of such tacked multifilament texturized synthetic yarns is influenced by the number of tacks per unit measure. If in the weaving process there are loom stops, yarn breakage, problems with the quality of the fabric, and so forth, believed to relate to the number of tacks per unit measure, the number of tacks per unit measure can be adjusted. In preferred embodiments of the present invention, the multi-filament texturized synthetic warp or filling yarn is tacked at intervals of from between about 10 to about 90 to about 100 tacks per meter depending upon the desired properties and end use. The higher the number of tacks per meter the greater the stability. The number of tacks per meter may be the same or different for the warp and filling yarn. The one preferred embodiment the number of tacks per meter is from about 50 to about 100. In a particularly preferred embodiment, the filling yarns have about 80 to about 100 tacks per meter. The higher the number of tacks per meter, the more likely it is that the appearance of the fabric will be affected by the tacks. However, this impact of tacks on appearance is acceptable for many products, including but not limited to, most laminated or coated fabrics. The tacks are preferably formed in the multifilament texturized synthetic yarns for use in the present invention by heating or by use of compressed air. In particularly preferred embodiments, the tacks are formed in the multifilament yarn by use of compressed air. While not wishing to be bound by theory, it is believed that the air forms tacks by local entangling of the filaments. Tacks formed in multi-filament yarn by entangling or interlacing are well known in the art. See, e.g., U.S. Patent No. 5, 184,381 at column 1 ; U.S. Patent No. 4,529,655 at column 3, lines 45-46, and column 4, lines 66-67; and U.S. Patent No. 4,069,564 at column 1, lines 41-52. Multifilament texturized synthetic yarns both untacked and tacked at predetermined intervals are standard articles of commerce available from manufactures such as Unifi, Inc., BASF and Milliken. Multiple ends of multi-filament texturized synthetic yarn can be wound directly onto a beam in a beaming operation and the number of ends per beam is limited only to the capacity of the yarn creel. A multiple of beams can be used to achieve the total number of ends needed for a specific width(s) of fabric on a loom. This capability permits elimination of customary slashing processes used for weaving resulting in cost savings and efficiency. Multi-filament texturized synthetic yarns are preferably prepared from partially oriented yarn (POY) available from manufacturers such as DuPont and NanYa Plastics Corporation of America. In one preferred embodiment, the loosely woven fabrics of the present invention comprise multi-filament texturized synthetic warp and filling yarns wherein either the warp or the filling yarn is tacked at predetermined intervals. In another preferred embodiment, both the warp and the filling yarns are tacked at predetermined intervals. These combinations offer economical and functional advantages over gauze fabrics made of spun yarns. The present invention will be illustrated by loosely woven fabrics prepared from multi-filament texturized polyester yarn wherein both the warp and filling yarns have been tacked at predetermined intervals. However, tacks can be provided in only one of the warp or filling yarns, in preferred embodiments the filling yarn, and any multi -filament texturized synthetic yarn which can be tacked at predetermined intervals is expected to be useful in the practice of the present invention. Multi-filament texturized polyester yarn wherein the filaments are air tacked at predetermined intervals is a preferred yarn for use in the gauze fabrics of the present invention. The denier of the multi-filament texturized synthetic yarn used will depend upon the intended end use but will typically be from between about 30 to about 300 denier and will have from between about 30 to about 70 filaments per strand. For example, 150 denier 34 filaments, 48 filaments, 100 filaments, 200 filaments. The number of filaments per yarn can influence the character of the fabric such as fabric hand (soft to softer) and possibly tear characteristics. The denier of the multi-filament texturized synthetic yarn can be increased to counts like about 100 to 150 denier for better warp tensile strengths, and possibly greater without significantly increasing tear strength. Through proper fabric design the desired tear characteristics can be achieved. Multifilament texturized synthetic yarns from 40 denier to 150 denier have yielded a tear which can be described as being consistent and smooth. Above 150 denier to 300 denier tear would be more appropriately described as being choppy, erratic or as non-tearable. If tear strength is not a factor, the denier can be increased to 300 and above. In the case of loosely woven fabrics used as substrates for adhesive tapes, the multi-filament texturized synthetic warp or filling yarn, both untacked and tacked, is from between about 30 to about 300 denier or more preferably from between about 70 to about 150 denier. In one preferred embodiment, filling yarns are about 150 denier. In preferred embodiments, the loosely woven fabrics of the present invention have a construction wherein the number of warp yarns per inch is from between about 14 up to about 63, more preferably up to about 44 and the number of filling yarns per inch is from between about 6 up to about 54, more preferably up to about 30 are useful. Although fabrics having from about 45 to about 63 warp yarns per inch and from about 31 to about 54 filling yarns per inch are not technically speaking loosely woven fabrics, they are to be included in the term "loosely woven" as used herein, because of their utility as substrates for adhesive tapes and other laminates. Loosely woven fabrics of the present invention having the number of warp yarns per inch in the range of from between about 14 to about 50 and the number of filling yarns per inch from between about 6 to about 45, are particularly useful for, e.g., duct tapes. The yarns, number of tacks per unit measure, denier and count of the loosely woven fabrics of the present invention are selected to provide the desired properties for the particular end product. In loosely woven fabrics of the present invention which are particularly suitable as a substrate for sports or medical tapes, the number of warp yarns per inch is up to about 63 and the number of filling yarns per inch is up to about 54. As mentioned above, these fabrics are not technically loosely woven fabrics. However, they are to be included in the term "loosely woven" as used herein, because of their utility as substrates for adhesive tapes and other laminates. The present invention also provides adhesive tapes, particularly duct tapes, which comprise a pliable backing, a substrate or a reinforcing fabric, and a layer of adhesive adherent to said backing material and to said reinforcing fabric, wherein the reinforcing fabric comprises a loosely woven fabric according to the present invention. The loosely woven fabrics of the present invention are particularly useful as substrates for duct tapes. The loosely woven fabrics of the present invention are especially superior substrates for duct tapes, because their use provides duct tapes having excellent tensile strength, thickness and appearance, as well as desirable tear characteristics. TENSILE STRENGTH: Tapes sold in the retail market primarily for home use do not require tensile strengths as great as tapes sold in the industrial market for such applications as AC duct wrap. Machine direction tensile strengths generally range from 10 to 45 pounds/inch. Cross direction tensile strengths generally range from 4 to 30 pounds/inch. Strengths are achieved by varying construction, yarn type, and yarn size. TEAR: Tape is generally torn across the warp yarns, but at times is torn across the filling yarns. Smooth, easy tear is more closely related to the tear characteristics of the individual warp yams and the close proximity of each warp yarn to each other. Ideal tear characteristic is similar to the smooth action of a zipper. THICKNESS: The thinner the fabric profile and the more space occupied by the fabric yarns, the less adhesive needed to cover the fabric spaces and surface. However, adequate space between yarns to allow penetration of adhesive through the fabric and attachment of, e.g., a vinyl film, is desirable. APPEARANCE: The smoother the surface of the fabric and the more perpendicular the warp and filling yarns are to each other, the better the tape appearance. The major duct tape property which is attributable to the adhesive is adhesive aggressiveness which affects ease of unwind. The properties of loosely woven fabrics of the present invention can be engineered using the appropriate yarns in proper proportions to form the duct substrate. Traditional fabric si ;y counts used in duct tape fabrics of 18 to 44 sley can be readily achieved in the fabrics of the present invention with the described texturized yarns. .Since texturized yarns can be produced in finer counts like 40 to 70D having higher yields, it is possible to produce a higher sley fabric at lower cost. The higher sley is less subject to weave distortion and the duct tape will have comparably smoother and easier tear characteristics. 70 denier texturized polyester yarn is equivalent in weight to a 75.93/ 1 cotton count yarn and has a strength similar to a 35/ 1 spun poly/ cotton yarn. Duct tapes for the retail and industrial market comprising tacked multi-filament, texturized synthetic warp yarns and filling yarns can be prepared from the fabrics prepared as described below. A multi-filament texturized 100% polyester yarn having about 80 to 90 tacks per meter is one preferred filling yarn for use in preparing duct tape substrates of the present invention. This filling yarn performed best on the loom and resulted in less weave distortion. Weaving Process: The loosely woven fabrics of the present invention are made by conventional methods and systems for forming the same. In such methods and systems care is taken to minimize the stress of the fabric as it is formed to minimize distortion by methods known in the art, e.g., by modification of all surfaces over which the fabric passes from stationary bars to rotating roll which turn very freely to prevent or minimize distortion and displacement of filling yarns, reduction of vibrations and so forth. It is highly desirable to modify the loom beam shaft to accept tricot beams in weaving the fabrics of this invention to thereby permit elimination of the slashing process. The tricot beam is used behind the loom. This result is a cost savings. Tape making process: Coating and laminating processes are known to be different in technique and application but in the case of duct tape some form of calender is generally used to attach vinyl film of chosen thickness to the fabric substrate of the present invention using an adhesive. The primary types of coating techniques include not only calendering, but also coating ranges, laminating machines, knife coating and roller coating machines. The preferred technique for duct tape is a calender which is capable of appropriate speeds. EXAMPLES Single 70, 100 and 150 denier/34 filaments 100% multi-filament texturized polyester warp yarn from Unifi Inc. with about 56 to about 93 air tacks per meter and 150 to 300 D/34 filaments 100% texturized polyester filling yarns having from about 50 to about 90 air tacks per meter were used in the manufacture of loosely woven 22 sley to 56 sley fabrics in accordance with the present invention as shown in Table I below. These fabrics were woven on a conventional airjet loom and wound onto a conventional off-loom take-up. The off-loom take-up eliminates the need to seam the fabric as often 30,000 to 50,000 yards without a seam. D = Denier TPM = Tacks Per Meter Gauze fabrics prepared as described above were used to make duct tapes suitable for the retail and industrial market and having excellent characteristics such as appearance, tear, strength. The duct tapes were made on a calender. The duct tape has zipper-like tear properties. As is amply illustrated by the various embodiments described herein, by following the teachings of the present invention one of ordinary skill in the art can vary the disclosed loosely woven fabrics and tapes in accordance with the present invention by utilizing ordinary skill in the art to meet the demands of a particular application and situation. Thus, it is understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof that will be suggested to persons skilled in the art are to be included in the spirit and purview of this application and the scope of the approved claims.

Claims: What is claimed: 1. A loosely woven fabric which comprises multi-filament texturized synthetic warp and filling yarns, wherein the filaments of at least one of the multi-filament texturized synthetic warp or filling yarns are tacked at predetermined intervals. 2. A loosely woven fabric according to claim 1, wherein the tacked multi-filament texturized synthetic warp yarn is tacked at intervals of from between about 10 to about 100 tacks per meter. 3. A loosely woven fabric according to claim 2, wherein the tacked multi-filament texturized synthetic warp yarn is tacked at intervals of from between about 50 to about 100 tacks per meter 4. A loosely woven fabric according to claim 1, wherein the tacked multi-filament texturized synthetic filling yarn is tacked at intervals of from between about 10 to about 40 tacks per meter. 5. A loosely woven fabric according to claim 4, wherein the tacked multi-filament texturized synthetic filling yarn is tacked at intervals of from between about 0 to about 100 tacks per meter. 6. A loosely woven fabric according to claim 5, wherein the tacked multi-filament texturized synthetic filling yarn is tacked at predetermined intervals of from between about 50 to about 100 tacks per meter. 7. A loosely woven fabric in accordance with claim 1, wherein the multi-filament texturized synthetic yarn comprises polyester. 8. A loosely woven fabric according to claim 1, wherein the multifilament texturized synthetic warp yarn is from between about 30 to about 300 denier. 9. A loosely wovi n fabric according to claim 8, wherein the multifilament texturized synthet c warp yarn is from between about 70 to about 100 denier. 10. A loosely woven fabric according to claim 8, wherein the number of filaments is from between about 30 to about 70. 1 1. A loosely woven fabric according to claim 1, wherein the multifilament texturized synthetic filling yarn is from about 40 to about 300 denier. 12. A loosely woven fabric according to claim 1 1, wherein the multi-filament texturized synthetic filling yarn is from between about 70 to about 100 denier. 13. A loosely woven fabric according to claim 11, wherein the number of filaments is from between about 30 to about 70. 14. A loosely woven fabric according to claim 1, wherein the number of warp yarns per inch is from between about 14 to about 50 and the number of filling yarns per inch is from between about 6 to abovit 45. 15. A loosely woven fabric in accordance with claim 14, wherein the number of warp yarns per inch is from between about 20 to about 26 and the number of filling yarns per inch is from between about 7 to about 10. 16. A tape which comprises a pliable backing, a reinforcing fabric, and adhesive adherent, wherein the reinforcing fabric comprises a loosely woven fabric according to any of the preceding claims 1 to 16.

Inventors: HUTTO ALONZO H JR, KEENER PHILLIP R, HUTTO, ALONZO, H., JR., KEENER, PHILLIP, R.
Applicants: AMERICAN FIBER & FINISHING S C, AMERICAN FIBER & FINISHING S.C., INC.
Application year: 2001
Main classification: D03D9
IPC codes: D03D1, D03D9, D03D15