Potentially crimpable composite filament yarn made of thermoplastic high polymers and usable for a crepe fabric

Abstract

A SELF-CRIMPABLE COMPOSITE FILAMENT YARN COMPRISING AT LEAST SINGLE FILAMENT COMPOSED OF TWO KINDS OF THERMOPLASTIC HIGH POLYMERS HAVING DIFFERENT VISCOSITIES AND ARRANGED IN AN ECCENTRIC DISPOSITION IN THE CROSS SECTION OF EACH FILAMENT, MATERIAL HIGH POLYMERS SHOULD BE CHOSEN FROM POLYESTER GROUPS AND THE DIFFERENCE IN VISCOSITIES THEREOF SHOULD BE LARGER THAN 0.05%. A CREPE FABRIC CONTAINING THE FILAMENTS CAN BE PROVIDED WITH REMARKABLY IMPROVED PEBBLES.

Claims

POTENTIALLY CRIMPABLE COMPOSITE FILAMENT YARN MADE OF THERMOPLASTIC HIGH POLYMERS AND USABLE FOR A CREPE FABRIC Filed Sept. 4, 1968 v 2- Sheets-Sheet 1 Jan. 5, 1597 1 MOTOTADA FUKUHARA IV-ITAL. ,55 MOTOTADA FUKUHARA ETAL POTENTIALLY CRIMPABLE COMPOSITE FILAMENT YARN Jan. 5, 1971 3,552,114 ' MADE OF THERMOPLASTIC HIGH POLYMERS AND USABLE FOR A CREPE FABRIC 2 Sheets-Shoot :3 Filed Sept 4, 1968 I B VJ XL. PM w 5 K M -m HM MMO o 3 H w m 9 H. F 1 E m O NUMBER OF CRIMPS DEVELOPED ON THE FILAMENT PER m cm. United States Patent Us. or. 57-140 5 Claims ABSTRACT OF THE DISCLOSURE A self-crimpable composite filament yarn comprising at least single filament composed of two kinds of thermoplastic high polyme'rshaving different viscosities and arranged in an eccentric disposition in the cross section of each filament. Material high polymers should be chosen from polyester groups and the difference in viscosities thereof should be larger than 0.05. A crepe fabric containing the filaments can be provided with remarkably improved pebbles. The present invention relates to a self crimpable composite filament yarn, more particularly relates to a self crimpable composite filament yarn suitable for developing pebbles on a woven or knitted fabric containing the filaments. In the specification, the term of filament yarn means a monofilament or multifilament yarn. The conventional method for manufacturing yarns used for crepe fabrics such as crepe wefts or textured yarns g'enerallyu'tilizes the so-called Italian twisting machine method or the false-twisting method, In both cases, the material yarn is processed by a multiple stage operation. For example, in the former case, the yarn is subjected to a process composed of winding up in the form of a pirn, rewinding, twisting, heat-setting of the twists, untwisting, sizing and winding up in the form of a filling cop, while in the latter case, the yarn is subjected to a process composed of winding up in the form of a pirn, false-twisting, sizing and winding up in the form of a filling cop. As is well-known by persons skilled in the art, the above-described complicated manufacturing process and the relatively low processing speed during the twisting operation, wherein usually a high degree of twisting is required, becomes a great barrier to increase in productivity. It is also required, in case of the above-described prior arts, to arrange yarns of different twisting directions alternately in the weaving structure of the fabric in order to develop a preferable pebbling effect on the fabric obtained. Generally, in the structure of a crepe fabric, yarns of S-twists and yarns of Z-twists are picked by ones, twos, threes, etc., and such special arrangement of the filling yarns can be obtained by using a loom provided with two shuttles. Therefore, an excellent pebbling effect on a crepe fabric can hardly be obtained by the ordinary loom provided with a single shuttle. Moreover, the mechanism of developing pebbles on the fabric includes partial elimination of strains temporarily imparted to the yarn configuration by twisting. It is therefore necessary to subject the yarn after twisting to a sizing operation in order to maintain the strained configuration of the yarn during the subsequent weaving operation before development of pebbles in the finishing operation. That is, sizing is an indispensable operation in the conventional manufacturing method of crepe fabrics. In order to eliminate the drawbacks possessed by the prior arts, the inventors of the present invention have in- 3,552,114 Patented Jan. 5, 1971 vestigated the possibility of manufacturing crepe fabrics provided with excellent pebbling effect by utilizing crimped composite filament yarns. It is widely known by persons skilled in the art that a composite filament composed of two different eccentrically arranged material polymers can be provided wtih crimps when the filament is subjected successively after spinning to a drawing operation at a given drawing ratio and a subsequent relaxation thermal treatment. Thus, it can be concluded that, by utilizing such self crimpable composite filament yarn, manufacture of a crepe fabric having excellent pebbling effect can be carried out on a loom provided with a single shuttle and without employing the sizing operation. However, it was further confirmed by the inventors of the present invention that some special characteristic features are required for such self crimpable composite filament yarn in order to obtain a crepe fabric having excellent pebbling effect. In case of the present invention, the so-called bimetallike arrangement of two component polymers in the cross section of the filament is included in the term eccentric arrangement. A principal object of the present invention is to provide a self crimpable composite filament yarn which can develop excellent pebbles on a woven or knitted fabric containing the filaments. Another object of the present invention is to provide a self crimpable composite filament yarn which can be utilized for manufacture of a woven or knitted fabric having excellent pebbling effect by a relatively simple method without employing a sizing operation which is indispensable in the conventional method. A further object of the present invention is to provide a self crimpable composite filament yarn which can be utilized for manufacture of a woven or knitted fabric having excellent pebbling effect without employing a twisting operation which usually results in low productivity in the conventional manufacturing method. A still further object of the present invention is to provide a self crimpable composite filament yarn which can be utilized for manufacture of knitted fabric having excellent pebbling effect on an ordinary loom provided with a single shuttle. As a result of repeated research work by the inventors of the present invention, it was confirmed that, in order to attain the above-described objects of the invention, the self crimpable composite filament yarn of the present inve'ntion should be provided with characteristic features such as the composite filament is composed of at least two kinds of thermoplastic high polymers, the filament is provided with from 16 to 35 crimps/cm. after treatment with boiling water, the maximum stress of contraction of the filament is larger than 50 mg./ denier, the temperature corresponding to the maximum stress of contraction of the filament is lower than C. and the percent of pebbling contraction of the fabric is larger than 40%. Further features and advantages of the present invention will be apparent from the ensuing description with reference to the accompanying drawings to which the scope of the invention is in no way limited. FIG. 1 is a schematic side view of a composite spinning process employed in the manufacture of the composite filament yarn of the present invention, FIG. 2 is a schematic side view of a drawing process employed in the manufacture of the composite filament yarn of the present invention, FIG. 3 is a schematic side view of a relaxation thermal treatment process employed in the manufacture of the composite filament yarn of the present invention, FIG. 4 is a graphical representtion of the result obtained with the illustrated example according to the present invention. Two important factors can be considered as affecting the pebbling effect on the fabric containing filaments of the present invention. One of the factors is the stress of contraction of the filament and the other is the number of crimps developed on the filament by the thermal treatment. The larger the stress of contraction, the better is the pebbling effect on the fabric obtained, and the stress of contraction should preferably be larger than 50 mg./ denier. The larger the number of crimps developed on the filament, the finer are the pebbles of the fabric obtained. Generally, it is necessary for the number of the crimps to be larger than 16 crimps/ cm. in order to obtain sufficient pebbling effect on the fabric obtained. However, as the number of crimps increases, the crimps developed on the filament become finer and too fine crimps results in a rather fiat appearance of the fabric surface. Therefore, there is an upper limit to the number of crimps developed on the filament in order to obtain a preferable pebbling effect on the fabric. It is therefore clear from the above discussion that the number of crimps should range from the purpose of developing pebbles. However, in case of the self crimpable composite filament yarn of the present invention which does not require a heat-setting treatment, a thermal treatment at a temperature lower than 200 C. is sufficient to develop preferable pebbles on the fabric obtained. Moreover, in case the temperature corresponding to the maximum stress of contraction is chosen lower than 190 C., development of preferable pebbles on the fabric together with sufficient heat-setting of the pebbles developed on the fabric can be completed simultaneously. This is one of the outstanding advantages of the present invention. Moreover, elimination of the thermal treatment of the filaments under a relatively severe processing condition, which is generally the case in the conventional falsetwisting method, assures uniform dyeing effect of the fabric containing the filaments. Again, crimps developed on the individual filaments due to the intrinsic difference in the shrinkability of the polymers composing the filament but not to strains mechanically imparted to the filament results in uniform development of pebbles on the fabric containing the filaments. This is another outstanding advantage of the present invention. With respect to material polymers composing the self crimpable composite filament yarn of the present invention, any knid of thermoplastic high polymers can be utilized although it is preferably composed of polymers substantially chosen from polyester groups for obtaining better pebbling effect on the fabric containing the filaments. The above-described polyester polymers should preferably be chosen in combination from a group composed of terephthalic acid, lower alkyl derivatives of terephthalic acid, ethylene glycol, bis-2-hydroxyl-ethylterephthalate or its low polymers and polyesters containing at least 70% by weight of polyethylene terephthalate. The combination of polymers chosen from the abovedescribed polyester group should be determined in such a manner that the difference in the intrinsic viscosities of polymers should be as hereinafter described. For example, a combination of terephthalic acid with ethylene glycol is preferably employed. The above-described polymers can also contain copoly mer components chosen from a group composed of aliphatic di-carboxylic acids such as oxalic acid, adipic acid and azelaic acid; aromatic di-carboxylic acids such as isophthalic acid, phthalic acid, 2,6-naphthalene di-car- 4 boxylic acid and diphenic acid; di-carboxylic acid having alicycles such as 1,2-cyclobutane di-carboxylic acid; dicarboxylic acid containing elements other than carbon, hydrogen and oxygen such as compounds having structures shown by the following general formulas, for instance 5 sodiumsulfophthalic acid and S-methylsulfophthalic acid; multifunctional compounds such as trimellitic acid and piromellitic acid; lower alkyl esters and glycol esters of such multifunctional compounds; polyoxy compounds such as di-ethylene-glycol, propylene glycol, polyethylene glycol, butendiol, tioglycol, p-xylylene glycol, l,4-cyclohexan-di-methanol, 2,2-bis(p-2-oxyphenyl) propane, 2,2-bis(p-oxyethoxyphenyl) propane, glycerol and pentaerythritol; and p-oxyethoxy benzoic acid, p-oxymethyl benzoic acid and glycollic acid. It is also possible for the polymers to contain such pigments as carbon black, phthalocyamine, titanium pigments and silicic anhydride, and phospho-compounds such as phosphoric acid, phosphorous acid, tri-phenyl-phosphate, trimethyl-phosphate and tri-phenyl-phosphate. Furthermore, in case the viscosity of the molten polyester solution is remarkably low, it is also recommended that additives such as boric compounds or aluminate compounds be mixed. With respect to the difference in the intrinsic viscosities of the material polyester polymers composing the filament of the present invention, better results can be obtained when the difference in the intrinsic viscosities is larger than 0.05. Moreover, it is preferably required that the intrinsic viscosity of the com onent polyester polymer of higher viscosity is in a range from 0.60 to 0.85 while that of the component polyester polymer of lower viscosity is in a range from 0.45 to 0.55. The characteristic features of the crimped composite filament yarn of the present invention were measured in the following manner. (1) Intrinsic viscosity of the material polymer.Limiting viscosity of the material polymer with respect to o-chlorophenol solution was measured at 25 C. (2) Number of crimps developed on the filament.A crimped filament having an effective length of cm. was loaded 1 mg./denier. In this condition, the number of the crimps in 10 cm. length of the sample was counted and converted into the number per 1 cm. length of the sample. (3) Stress of shrinkage of the filament.A crimped filament having an effective length of cm. was loaded g./denier and, in this loaded condition, the sample was immersed in a silicone oil bath maintained at C. Stress produced in the filament was measured with a strain meter while increasing the temperature of the bath up to 230 C. at a rate of 5 deg/min. (4) Percent thermal shrinkage of the undrawn filament.-A bundle composed of 20 undrawn filaments were loaded 200 mg./denier and the length (L of the bundle in this loaded condition was recorded. Next the bundle were immersed in a boiling water bath for 15 minutes under a load of 1.2 mg./denier. After thermal treatment, the length (L of the bundle was again recorded. Then the percent thermal shrinkage of the undrawn filament was obtained by the following, (5) Percent pebbling contraction of the fabric.Filament yarns composed of a plurality of conventional filaments of 2 denier and twisted at a twisting rate of 100 turns/meter, were used as the warps and filament yarns of the present invention were used as the fillings. Both component yarns were provided with substantially similar total fineness. A plain woven fabric having a warp density of 100 ends/inch and a filling density of 80 picks/ inch was manufactured with the yarns. First, the width in grey (D of the fabric was measured. Next, the fabric was immersed in a boiling water bath in a free condition for 20 minutes for the purpose of developing pebbles. After pebbles have developed sufiiciently, the fabric was dried in a free condition and the width after finishing (D of the fabric was measured. Then, the percent pebbling contraction of the fabric was obtained by the following, The method for manufacturing a self crimpable filament yarn of the invention will now be described. As the material polymers composing the filament, two kinds of polyester polymers having different intrinsic viscosities are used. One of the polyester polymers is provided with an intrinsic viscosity ranging from 0.45 to 0.55 while the other polyester polymer is provided with an intrinsic viscosity ranging from 0.60 to 0.85. Both polymers are fed to a composite spinning process held at a spinning temperature between 295 and 305 C. In this spinning, it is not desirable to subject the spun filaments to a sudden coagulation which is generally employed in the conventional spinning process of synthetic filaments. About 120 to 150 mm. downstream of a spinneret, there should be formed a calm windless zone, and the temperature measured at a position 30 mm. under the spinneret and mm. horizontally away from the periphery of the spun filaments stream should be maintained at about 180 C. After passing through the calm windless zone, the filaments are coagulated with a coagulating air flow maintained between and C. and taken up onto a package without the drawing operation at taking-up speed of about 900 meters/min. By the above-described spinning-windless zone passing coagulation taking up process, the undrawn composite filament obtained is provided with a percent thermal shrinkage in a range between 16 and 24%. Next, the undrawn filaments are subjected to a drawing operation at a drawing ratio from 3.6 to 4.0 while passing through a drawing zone comprising a heated pin maintained at about 100 C. and a heated plate maintained from 130 to 180 C. After this drawing operation, the drawn filaments are next subjected to a relaxation thermal treatment while passing through a heated cylinder maintained between 80 and 160 C. and while being held at a relaxation ratio from 5 to The self crimpable composite filament yarn of the present invention can be obtained not by a random combination of the conditions but only a certain preferably designed combination of the conditions among the above-described processing conditions as will be madeapparent in the examples hereinafter described. Referring to FIG. 1, an embodiment of the composite spinning process employed in the manufacture of the composite filament yarn of the present invention is schematically shown. In the process shown in the drawing, chips of the material polymers are melted in the respective melter 1a and 1b. After being melted independently, the molten polymers are fed to a composite spinneret 3 by way of the respective gear pumps 2a and 2b and are extruded through the spinneret 3 in the form of a plurality of composite filaments4 composed of the two different kinds of material polymers arranged in an eccentric disposition in the cross section of the individual filament 4. The outlet side of the spinneret 3 is provided with a cylindrical shelter 5 having a length from 120 to 150 mm. to form the above-described calm, windless zone. The strand of filaments 4 coming out of the cylindrical shelter 5 is exposed to a coagulating air ejected from a cooling chimney 6 disposed directly downstream of the cylindrical shelter 5. After coagulation, the filaments 4 are taken up onto a bobbin 10 driven by a take-up roller 9 in the form of a package 11 while the processing tension is being adjusted by a pair of godet rollers 7 and 8 disposed in the passage of the filaments 4. Next, the filaments 4 in the form of the package 11 is supplied to the drawing process shown in FIG. 2, wherein, the undrawn filament yarn 4 is drawn out from the package 11 by a pair of feed rollers 14a and 14b by way of yarn guides 12 and 13. A drawing roller 15 is positioned downstream of the feed rollers 14a, 14b and the undrawn filament yarn 4 is drawn Within a zone between the feed rollers 14a, 14b and the drawing rollers 15 by the difference in surface speeds of both rollers. During this drawing operation, the filament yarn 4 passes through the zone while contacting a heated pin 16 and a heated plate 17, both of which are positioned within the zone. After this drawing operation, the drawn filament yarn 18 is taken up onto a bobbin 19 in the form of a cop 20 by any of the known method. Referring to FIG. 3, an embodiment of the thermal relaxation treatment process preferably employed in the manufacture of the composite filament yarn of the present invention is schematically shown. In the drawing, the drawn filament yarn 18 is drawn out from the cop 20 by a pair of feed rollers 22a and 22b by way of a yarn guide 21. A pair of relaxing rollers 23a and 23b are also positioned downstream of the feed rollers 22a, 22b and a heated cylinder 24 is disposed Within a zone between the pair of rollers. After passing through the feed rollers 22a, 22b, the drawn filament yarn 18 is sucked into the heated cylinder 24 by an air ejector 25 disposed to the inlet end of the heated cylinder 24 and is subjected to a thermal relaxation treatment while passing therethrough. After the treatment, the filament yarn 18 provided with numerous curled crimps is taken up onto a bobbin 26 in the form of a package 27 in any of the known manners. The following examples are illustrative of the present invention but are not to be construed as limiting the same. EXAMPLE 1 Two kinds of poylethyleneterephthalate chips having intrinsic viscosities measured in orthochlorophenol of 0.80 and 0.45 were used as material polymers. The material polymer chips were fed to the process shown in FIG. 1, wherein molten polymers were composite spun at a spinning temperature of 300 C. in the form of composite filaments having a bimetal-like cross sectional profile. After coagulation, the filaments were taken up onto a package in the form of a multifilament yarn of 50 denier containing 24 filaments. In the above-described spinning process, the length of the cylindrical shelter was mm., the temperature at a position 30 mm. Under the spinneret and 10 mm. horizontally away from the periphery of the filaments strand was maintained at 180 C., the temperature of the coagulating air ejected from the cooling chimney was maintained at 18 C. and the thermal shrinkage of the undrawn filament thus obtained was 16.2%. Next, the undrawn filament yarn thus obtained was fed to the process shown in FIG. 2 and was drawn at a drawing ratio of 3.8. In the process, the heated pin was maintained at 100 C. and the heated plate was maintained at 160 C. After the drawing operation, the drawn filament yarn was fed to the process shown in FIG. 3 and subjected to a relaxation thermal treatment at a relaxation ratio of 15% and a processing temperature of C. The characteristic features of the composite filament yarn thus obtained are shown by sample No. l in Table 2; tenacity of the yarn was 3.7 g./ denier, breaking elongation was 18.3%, number of crimps developed on the filament was 22.0 crimps/cm. after treatment in boiling water, the maximum stress of shrinkage was 190 mg./denier and the temperature corresponding to this stress was 148 C. Further, a crepe fabric was manufactured using the composite filament yarn thus obtained. The crepe fabric thus obtained was provided with a pebbling contraction plastic materials eccentrically positioned with repect to each other in cross-section of said filament; said filament having from 16 to 35 crimps per centimeter of axial length and a maximum shrinkage stress greater than 50 mg./denier at temperatures less than 190 C. of 50% and had sufficiently developed pebbles of the 5 2. A composite filament yarn according to claim 1; preferable appearance. wherein said two different high polymer thermoplastic materials comprise polyester materials. EXAMPLE 2 3. A composite filament yarn according to claim 1; In a manner similar to that employed in Example 1, wherein each of said high polymer thermoplastic mavarious types of composite filament yarn and crepe fab- 10 terials has an intrinsic viscosity when in a molten state, i Were ma ufa tu d Processing Conditions were suband wherein the difference in intrinsic viscosities of said stantially similar to those employed in Example 1 with two different high polymer thermoplastic materials is the exception of those illustrated in Table l. greater than 0.05. TABLE 1.PROCESSING CONDITIONS Intrinsic viscosities of the material polymers: High. 0.60-0.85. Low 0.45-0.66. FiHOlKES of individual filaments in denier 24. Total fineness of the multifilarnent yarn obtained in denier. 50. Thermal shrinkage of the undrawn. filaments in percent... -30. Drawing ration in percent 3.3-4.3. Temperature of the heated pin in C... 100. Temperature of the heated plate in C 0 below 100 or without heat. Processing temperature during relaxation thermal treatment in 0. Relaxation ratio in percent. -40. Room temperature, 230. By various combinations of the processing conditions listed in Table 1, 16 sample yarns were prepared and the properties of the resulting sampleyarns are illustrated by samples Nos. 2 to 17 in Table 2. Further, crepe fabrics are manufactured using the respective sample yarns. The functional properties of the sample fabrics are also illustrated in Table 2. TABLE 2 Sample No. 1 2 3 4 5 6 l 8 0 10 11 12 13 14 15 16 17 Properties 01 the yarn: Tenacity in g./denier 3. 7 3.8 3.8 3. 5 3.5 3. 7 3. 7 3.4 3.7 3. 6 4. 2 3.8 3.5 3.2 3. 4 3.2 3.3 Breaking elongation in percent... 18. 3 21. 8 24. 0 26. 5 22.0 17. 6 20. 6 27.5 17. 7 21. 5 21. 5 17.8 24. 0 4. 5 23. 5 24. 0 22. 7 Number of crimps per/cm 22. 0 15. 5 14. 7 17.2 25. 3 36. 0 18. 7 13v 2 27. 2 24. 3 9. 0 32. 3 3. 2 13. 0 30. 0 22. 8 19. 0 Stress of contraction in ing/denier 100 200 100 42 48 70 160 100 250 170 30 62 58 Temp. corresponding to the stress in 0.... 148 148 147 120 200 150 152 215 150 150 142 175 158 200 188 Properties of the fabric: Pebbling contraction in percent. 50 68 35 15 18 30 55 16 4. 5 42 40 60 1O 20 48 38 42 Development of pebbles O O A X X A O X A A X 0 X X 0 A A Appearance of pebbles O X X O A O O O X O 0 Height of pebbles. 0 O A X X A O X A A O O X X 0 X A Handling O A A X A X 0 X 0 O X 0 X X 0 X 0 Total appreciation O X X X X X 0 X 0 O X 0 X X 0 X 0 NOTE: In the table, the symbol 0 indicates excellent; the symbol A" indicates not suilicient; and the symbol X" indicates poor." The results obtained are graphically shown in FIG. 4, wherein the stress of shrinkage is taken on the ordinate while the number of crimps is taken on the abscissa. In r the drawing, the numerals attached to the plots corresponds to the numbers of samples listed in the table and the results obtained according to the present invention should fall within the area of the oblique shadings. In the results obtained, the filament yarn of sample No. 16 is regarded as satisfying the object of the invention as it is within the area. However, the filament yarn of sample No. 16 is actually not suitable for the purpose of the invention because the temperature corresponding to the maximum stress of shrinkage is higher than 200 C., which causes deterioration of the functional properties of the crepe fabric obtained. In case the characteristic features of the yarn falls outside the area shown in FIG. 4, it is impossible to manufacture crepe fabrics provided with excellent pebbling effect and excellent handling from such material yarns. While the invention has been described in conjunction with certain embodiments thereof, it is to be understood that various modifications and changes may be made without departing from the spirit and scope of the in- Vention. What is claimed is: 1. A composite filament yarn comprising: at least one filament composed of two different high polymer thermoin manufacturing a crepe yarn comprising: at least one filament composed of two kinds of high polymer thermoplastic material eccentrically disposed with respect to each other in cross-section of said filament; said filament having a potentially crimpable property of developing 16 to 35 crimps per centimeter of axial length; and wherein said filament has a maximum shrinkage stress greater than 50 mg./denier at temperatures less than 190 C. References Cited UNITED STATES PATENTS 3,117,362 1/1964 Breen 57140 3,137,989 6/1964 Fior et al. 57140 3,181,224 5/1965 Tanner 57l40X 3,199,281 8/1965 Maerov et al 57140 3,350,871 11/1967 Pierce et al 57-140 3,365,873 1/1968 Matsumoto et al. 57-157 3,404,710 10/1968 Pierce 57l40X 3,444,681 5/1969 Reese 57140 3,446,005 5/ 1969 Kosaka et al. 57140X STANLEY N. GILREATH, Primary Examiner W. H. SCHROEDER, Assistant Examiner

Description

Topics

Download Full PDF Version (Non-Commercial Use)

Patent Citations (0)

    Publication numberPublication dateAssigneeTitle

NO-Patent Citations (0)

    Title

Cited By (3)

    Publication numberPublication dateAssigneeTitle
    US-4241002-ADecember 23, 1980Standard Oil Company (Indiana)Process for producing homogeneous curly synthetic polymer fibers
    US-5996328-ADecember 07, 1999Basf CoporationMethods and systems for forming multi-filament yarns having improved position-to-position consistency
    US-7096888-B1August 29, 2006Honeywell International, Inc.Fluidic pulse generator system