US3549741A

US3549741A - Process for preparing improved carpet yarn

Info

Publication number: US3549741A
Application number: US834570*A
Authority: US
Inventors: Lloyd Caison
Original assignee: Individual
Current assignee: Allied Corp
Priority date: 1967-10-30
Filing date: 1969-03-05
Publication date: 1970-12-22
Anticipated expiration: 1987-12-22

Description

United States Patent O U.S. Cl. 264-210 Claims ABSTRACT OF THE DISCLOSURE The invention provides a process for preparing a carpet yarn from a dispersion of polyester in fiber-forming synthetic linear polyamide, especially poly-l-caproamide by selectively controling the spinning, drawing, crimping and aftertreating conditions whereby a yarn having excellent pattern definition, superior resilience and a velvety sheen is produced.

BACKGROUND OF THE INVENTION This application is a divisional of US. application Ser. No. 679,202 filed on Oct. 30, 1967, and now abandoned.

This invention relates to a process for producing multifilament yarn from a dispersion of fiber-forming polyester in fiber-forming polyamide generally in accordance with US. Pat. 3,369,057, dated Feb. 13, 1968, to Twilley. Carpet yarn is required to meet high standards of uniformity in performance in carpet-making operations including dyeing in a hot aqueous bath and tufting by passing loops through a backing sheet. In addition to uniform performance, the yarn must have high performance in terms of retaining its appearance under conditions of wear and soiling; and in addition is required to develop high bulk in the final carpet so that a given weight of yarn will sufiice for making a relatively large area of carpet. For example, where wool is used at a weight of say 30-40 ounces per square yard, a synthetic fiber with good bulk can be used at weights in the range of -20 ounces per square yard.

Besides the fundamental properties above mentioned of uniform performance, durability and high bulk or cover, carpt yarns are valued for their ability to produce pleasing aesthetic effects. Among the effects desired are a springy yielding to the touch, so that the carpet pile yields without flattening completely under gentle pressure, then returns promptly to its original height; good pattern definition, i.e., clear delineation between areas of different pile height in a tufted carpet; sparkle giving an effect of depth; velvetlike sheen in cut or sheared pile constructions.

SUMMARY OF THE INVENTION In accordance with the present invention a process for producing multifilament textured yarn is provided which comprises extruding through a multihole spinnerette a molten fiber-forming polyamide having a polyester dispersed therein in weight proportions of about 90:10 to 60:40 of polyamide:polyester to form a multiplicity of filaments. Each of the filaments are formed from an eX- trudate hole providing a capillary area of 7X10- to 12 10- square inches and attenuated while in a molten condition within the quench stack by a draw-down ratio of about 70 to 120. The capillary area may be composed of a single hole of any desired configuration or a plurality of closely spaced holes. After solidification, the filaments are stretched about 3.5 to 5 times their original length whereby the resulting filaments have a denier of 3,549,741 Patented Dec. 22, 1970 about 5 to 20. In order to improve the bulk or covering power of the yarn, an average of at least about 8 crimps per inch is imparted to the yarn in apparatus such as stutter-box crimpers, steam jet texturing devices and gear-type crimpers. The high cover and better pattern definition characteristics are further enhanced by correlating the crimping and an after crimp stretching operation to confer crimp elongation off the package not above about 10 percent while maintaining crimp elongation after boil in the range of 15 to 40 percent. The after crimp stretching operation involves stretching the filaments an additional 5 to 15 percent beyond their true length.

PREFERRED EMBODIMENTS OF THE INVENTION The process of this invention employs a dispersion of polyester in polyamide, in particular from a dispersion of about 10-40 parts by weight polyethylene terephthalate in correspondingly -60 parts poly-l-caproamide. This polycaproamide, as disclosed in the above-cited US. Pat. No. 3,369,057 to Twilley, must have a low level of primary amino groups. A prefered level is in a range from about 5 to about 20 meq. per kg. (i.e., milliequivalents of primary amino groups per kilogram of polycaproamide). The polyester must be well dispersed, as accomplished for example by mixing and melting the polyamide and polyester together in a melt extruder wherein the mixture is sheared by rotation of the screw, then forwarding the melt through pipes at a velocity to maintain shearing conditions and passing the melt through a filter of finely divided material such as sand or sintered metal particles.

The operations thus far outlined are in accord with one conventional practice for spinning nylon. However, to obtain filaments of satisfactory quality with respect to denier uniformity and freedom from breaks while opcrating at high production rates in the spinning and drawing process, it has now been found that an unusually large area for the capillary or capillaries making up each of the spinnerette holes should be used, viz, an area totaling about 7X 10- to 12 10 square inch per spinnerette hole, as obtained, e.g., with three capillaries grouped closely together in one hole so as to form three streams of melt which coalesce to a trilobal filament, each capillary having diameter of about 18-22 mils. The capillaries commonly used similarly for spinning of trilobal nylon yarn are 14 mils in diameter; thus the capillaries used in melt spinning in accordance with the invention have areas from about 65 to percent greater than that of the holes normally used for spinning nylon of the same viscosity as the polycaproamide nylon used in the subject dispersions. Multilobal or other modified off round filament cross sections are preferred, both for their greater cover and for better sparkle than round cross sections. Particularly suitable cross sections are the trilobal cross sections disclosed and claimed in US. Pat. No. 3,216,186 dated Nov. 9, 1965 to Opfell.

The diameter of the uncrimped, drawn filaments of the present invention is generally in the range giving a denier per filament of about 5-20. This diameter is attained, from the filament as extruded through the holes, by a combination of attenuating or drawing down the molten filament and permanently streaching or drawing the solidified filament. The attenuation or stack draw down can be calculated from the volumetric throughput q, the capillary area A, and the windup speed S by the formula: Attenuation=SA/q (the quantities being expressed in consistent units). In the present invention the attenuation is maintained considerably above normal levels, viz, about 70-120 versus about 40-50 for nylon spinning.

Moreover, in the filaments of the present invention, it is found that the final draw ratio of the solidified filament must be in the range between about 35:1 and :1 as measured by the ratio of peripheral speed of the final draw rollzspeed of feed roll supplying the undrawn yarn to the draw zone. Thereby the solidified filament is molecularly oriented along its length as shown for example by X-ray. For good uniform dyeability this orientation should be substantially uniform; and such can be achieved in the filaments of this invention by use of the above range of draw ratio, while at the same time good drawing performance can be obtained, i.e., low bundle breaks and low breaks of individual filaments causing the filament to wrap about the draw roll.

Preferably, the ultimate elongation (UE) and ultimate tensile strength (UTS) of the uncrimped yarn of this invention, both as measured on the Instron tensile tester, are in the ranges of 25 to 75 percent UE and about 2.6 to 6 grams per denier UTS.

These drawn, oriented filaments are preferably about 8 to 20 denier and contain polyester microfibers dispersed therein, mostly oriented lengthwise of the filament axis. The microfibers are too fine, in the drawn filaments, to be observable in cross section under an optical microscope, but can be observed using the electron microscope. These diameters generally average in the range from about 0.02 to 0.3 micron depending upon factors such as fineness of the dispersion of molten polyester in molten polyamide, draw ratio used, etc. Their length exceeds their diameter by manyfold, generally at least 250-fo1d.

To attain the property of cover or bulk, a drawn feeder yarn must be textured or crimped. The above-described drawn yarn is found to be well suited to taking a good crimp. An angular crimp is particularly suitable as obtained, for example, by steam jet crimping against a wad of crimped yarn or by stuffer box crimping. Steam jet crimping against a wad produces a random angular crimp in which the irregularities blend out overall to give satisfactory uniformity. In stutfer box crimped yarn, the crimping can be and desirably is controlled for uniformity within about :20 percent in terms of crimps per inch. A suitable range for average crimps per inch is about 8 to-17. The UE of the yarn being crimped influences the crimp uniformity, since too high UE results in streaching the yarn instead of feeding it forward for crimping.

Crimp elongation off the package and crimp elongation after boil are important characteristics which must be kept uniform within at least the range of :5 percentage units. The average crimp elongation off the package should not exceed 10 percent, and the average crimp elongation after boil should be in the neighborhood of to 40 percent for the textured yarns of this invention. 1

The above crimp parameters can be defined with respect to the diagram which appears below.

ELBOW (a) Leg Length is the distance between midpoints of the bends in the filament.

(b) Elbow is the midpoint of the filament bend.

(c) Crimp Angle is the angle formed by two legs on either side of an elbow.

(d) Crimp/Inch is equal to one-half the number of leg lengths in an inch of filament (an inch as measured when the filament is straightened out, i.e., when the crimp angle is fully open). Crimp/ Inch is measured by counting the total number of elbows in an inch of straightened filament and dividing by two.

(e) Crimp is the combination of Crimp/Inch (Leg Lengths) and crimp angles which makes textured yarn different from normal drawn yarn.

Crimp elongation is measured by hanging a length of the crimped yarn under an added load of 0.1 gram per denier for a period of 2 seconds (length L under which condition the crimp angle is largely straightened out (i.e., brought practically to 180), and then removing the load and again measuring the length of the same fiber hanging under no added weight after an elapsed time of at least 15 seconds (length L The percent crimp elongation (CE) is calculated as:

Crimp elongation off the package is the value obtained for the yarn withdrawn from the package for use in carpet making, particularly in tufting. It is of critical importance in the tufting process that this value be not over 10 percent, since the control of the size of loops depends upon following, with the yarn, the motion of the tufting needle. If the yarn stretches excessively, the needle motion will not be followed with sufficient accuracy. It will be appreciated that the hot, humid conditions often found during the summer months in carpet mills may increase the crimp elongation otf the package by the same action as in dyeing (discussed below); thus it is important that the crimp elongation off the package be stable under such humidity conditions. This is one of the respects in which the present yarn shows unexpected superiority over similar nylon yarns, for reasons not entirely understood.

Crimp elongation after boil is the value of the crimp elongation measured as described above, after subjecting the yarn, as removed from the package, to boiling water for one hour under no tension. The same value can be obtained more quickly by subjecting the yarn to a steam spray. It represents a sharpening of the crimp angle from about 130 in the yarn as it comes off the package to about 110 to representing a change of crimp elongation due to boiling, from a maximum of 10 percent off the package to a range between about 15 percent and about 40 percent after boil. This 1540 percent range after boil is critical to give the yarn of the present invention its high cover combined with its capability of achieving exceptionally good pattern definition between high and low areas in the pile of a tufted carpet. With the present yarns, a crimp elongation after boil materially less than 15 percent results in insufiicient bloom or spreading out of the tufts under the influence of hot, Wet conditions as in dyeing, hence results in unsatisfactory cover. A crimp elongation after boil of greater than about 40 percent in these yarns, on the other hand, results in too tight a crimp so that the pile of a tufted carpet will pull down into a tight wad under the hot, wet conditions of dyeing, and will be tight against the backing rather than being high and bulky.

Crimp elongation after boil is determined primarily by the crimping conditions in the zone where the crimp is first formed, ordinarily a hot zone. In mechanical crimping such as stuffer box crimping this heat will be generated by the work done by the crimp rolls in bending the yarn against resistance of the yarn wad and the outlet gate; commonly it is necessary to cool the rolls and/ or the crimping box to avoid fusion of the filaments. To reduce the work done on the filaments and thus reduce this heat generated in mechanical crimping, it is advantageous to plasticize the filaments by a pre-treatment under hot, moist conditions, e.g., with steam.

The primary factor determining crimp elongation off the package, and also an important factor in determining crimp elongation after boil, is post-treatment of the crimped yarn after it leaves the stulfer box.

The yarn of the present invention, it has been found, is more susceptible to crimping than is nylon yarn of the same nylon used in the nylon/polyester dispersion from which the present yarn is produced. Moreover, the crimp imparted in the crimping box, in the hot zone of a steam jet, or otherwise in a hot zone is quite easily removed from the freshly crimped yarn of the present invention,

it has been found. Accordingly, to produce the yarn of the present invention with not over 10 percent crimp elongation off the package and with 1540 percent crimp elongation after boil, it is found that the yarn should be crimped at about 8-17 average crimps per inch; and should then be cooled as it leaves the crimping zone. The cooled, freshly crimped yarn must then be stretched by about -15 percent beyond its fully straightened out length. This positive stretch should be adjusted to confer crimp elongation off the package of not greater than percent, but should be limited to maintain crimp elongation after boil of at least percent; the adjustment will usually give a positive stretch in the indicated range of 5-15 percent beyond the length of the yarn with the crimps straightened out. This stretch can suitably be obtained in stages which first partially straighten out the crimp under light tension of about 0.1 g.p.d. to allow handling the yarn in nip rolls, then further stretching the yarn between rolls. Although the crimp elongation in freshly crimped yarn is quite easily reduced by stretching, nevertheless this yarn after the usual dyeing operations at the boil will recover crimp elongation and retain this recovered crimp with good permanency. Thus the processing required to obtain yarn for use in tufting is unexpectedly simple.

For use as feeder yarns for tufting, several ends of yarn as above described are plied together at say 2 to 10 turns per inch. The plied yarns can be of varied type such as Saxony, Frieze or Cable styles. Saxony and Frieze yarns consist generally of 2 or 3 yarns plied at 48 turns per inch twist in a twist direction opposite to the direction of twist in the individual yarns. Cable type yarns can in general be made by plying together more than 2 yarns with a ply twist of 1V: to 3 turns per inch in the direction opposite to the twist in the individual yarns. The individual yarns employed in such plied structures can be spun yarns made from staple filaments, or continuous filament yarns which can have up to 8 turns per inch of twist. The individual yarns can also contain cohesive finishes or sizes, and can be cohered via interfilament commingling as described in U.S. patent application Ser. No. 535,480, of F. W. Le Noir, filed Mar. 18, 1966.

When such plied yarns are heat-set, it is found that upon forming a pile carpet and cutting or shearing off the loops, a high velvety sheen will be produced in the resulting carpet. This capability of the present yarns to produce such velvety sheen in a cut or sheared pile is a striking and valuable property.

The heat setting of plied yarns can be carried out continuously, or batchwise. In any event, the yarn should preferably be in tensionless condition during heat setting to avoid removal of the crimp in the filaments. In a continuous operation, tensionless treatment is best achieved by subjecting the yarn to treatment while supported on a moving belt. Superheated steam, as obtained in suitable autoclave apparatus, is generally the preferred form of heat treatment. Dye can be applied to the plied yarn prior to heat setting to secure dye penetration and heat setting in the same operation.

The yarns can be made to contain various additive ingredients which impart specialized properties. For example, ingredients which can be added to the yarn either by incorporating within the polymer prior to spinning, or by after-treatments of the yarn or fabric include flame retardant agents such as compounds of antimony, phosphorus, and halogens; titanium dioxide delustrant; antistatic agents; adhesion promoting agents such as isocyanates and epoxides; heat and light stabilizers such as inorganic reducing ions, metal ions such as manganese, copper and tin, phosphites, and organic amines such as alkylated aromatic amines and ketone-aromatic amine condensates; thermally stable organic pigments such as 2,9-dimethylquinacridone and inorganic pigments such as titanium dioxide; fluorescent agents and brighteners such as Tinopal PCR; cross-linking agents; bacteriostats such as phenols and quaternary amines; colloidal reinforcing particles; antisoiling coatings such as colloidal silica and boehmite; antistatic or antisoiling additives such as polyamino compounds or polyethers; and other known additives and treatments. It is essential however that esentially no volatile ingredients such as water or solvents be contained by the polymer prior to extrusion since these are deleterious to satisfactory extrudate coalescence. The presence of plasticizers however is beneficial to extrudate coalescence, and these can be removed if desired after filament formation. In the case of polycaproamide polymer, the presence of about 0.5-2 percent of monomeric lactam which acts as a plasticizer, facilitates extrudate coalescence.

The above described continuous filaments of this invention can be cut into staple and used in that form in pile carpets. Short staples or flock can likewise be produced and applied to a backing by conventional flocking methods.

The yarn of this invention can be dyed to advantage with anthraquinone dyes, as disclosed and claimed in copending US. application Ser. No. 548,381 of Ortheil et al. filed May 9, 1966; and also to advantage with disperse azo dyes which are substituted by at least 2 electronattracting substituents, especially those of the group (CH X (n being an integer from 0 to 6 and X being halogen or -'C=-N), and NO Examples are the following dyes identified by their code numbers of Colour Index, volume 3, 2nd edition (1957)-The Society of Dyers and Colourists and The American Association of Textile Chemists and Colorists): Nos. 11100; 11150; 11230; 11310; 11420.

As has already been noted, when the yarns of the present invention are employed for tufting, they perform exceptionally well in the machine and allow a very exceptional sharp contrast between high and low pile regions, i.e., very superior pattern definition; and this is especially true under humid and hot conditions such as 50 percent and higher relative humidity at 20 C. or higher temperatures. The compressional resilience of these yarns of this invention is also appreciably better than a like yarn from all nylon, as measured visually by recovery from compression under load or as measured by work recovery, i.e., area under the stress-strain curve for recovery from 1 percent elongation: area under the stress-strain curve passing to 1 percent elongation of the uncrimped yarn. The stress-strain curves can be obtained for example with the Instron tensile tester. The improved compressional resilience is found under hot, wet conditions as in dyeing as well as under normal conditions; and this compressional resilience during dyeing is one of the factors contributing to the superior pattern definition, since in piece dyeing as commonly practiced for carpets the goods are packet together so that the pile is compressed.

In the examples which follow, the polyamide used is poly-e-caproamide; however, the invention is not confined thereto and can be practiced similarly using other melt spinnable fiber-forming synthetic linear polyamides of which polyhexamethylene adipamide (nylon 66), polyhexamethylene sebacamide (nylon 6, 10) and polyhendecanamide (nylon 11), together with copolymers of these with other polyamide-forming units, are representative examples.

EXAMPLES The following examples are illustrative of the present invention and of the best mode presently contemplated of carrying out the invention; but the invention is not to be interpreted as limited to all details of the examples.

In the example of the table below, 70 parts by Weight of particles of poly-e-caproamide (having about 20 meq. of primary amino groups per kg. of polyamide) and 30 parts by weight of polyethylene terephthalate were mixed. The polycaproamide contained about 0.3% of titanium dioxide dulling agent and about ppm. of manganese as its chloride plus hypophosphorous acid light stabilizer. The polycaproamide had relative viscosity in aqueous 90% formic acid (by ASTM Test D-789-62T) of about 56 and the polyethylene terephthalate had reduced viscosity of about 0.83 dl./gm. as measured at C. and polymer concentration of about 0.5 gram per 100 milliliters in purified orthochlorophenol containing 0.1% by weight of water. Moisture content was kept not above 0.04% in the incoming particle mixture.

This mixture was melted and fed by an extruder to a metering pump whcih supplied a melt spinning pack comprising a finely porous filter and a spinnerette having 70 capillary holes, each of Y-shaped configuration. Each hole of Run A had area of 8.1 10 sq. ins. and the holes of Run B each had area of 7.2 10 sq. ins. The extruder was operated to produce a pressure of about 30003500 pounds per square inch at the outlet.

The temperature of the molten polymer at the pump was about 275 C. and the temperature of the spinnerette pack was about 265 C. The molten polymer upon extrusion through the spinnerette descended a spinning tower in contact with air admitted at 82 F. and 65% relative humidity. After windup, the solidified yarn was drawn at 3.87:1 draw ratio. The spinning, quinching, windup, and drawing operations were otherwise essentially as described in U.S. Pat. 3,216,186, dated Nov. 9, 1965, to Opfell, at column 7, lines 1-30.

Although such was not done in the example of the table below, it is advantageous, especially when using polyamide of high formic acid relative viscosity such as 70100, to employ in the spinning tower a heated sleeve as described in Swanson et a1. U.S. application Ser. No. 752,414 filed June 18, 1968, Example 1 thereof. The sleeve is heated to produce, at a point one-half inch down from the spinnerette, a temperature in the range 320-380 C., and the sleeve extends suitably 3 inches to 6 inches below the spinnerette to maintain a quiescent atmosphere in that zone. The sleeve temperature is adjusted to provide good spinning performance, and is held constant to :5 C. Too low a temperature results in nonuniform filament denier; and too high temperature causes drips. Use thereof gives generally better spinning performance and particularly, less variable spinning performance in terms of drips due to filament breaks at the spinnerette. A preferred embodiment of this invention involves the use of such heating in the spinning tower and use of polycaproamide of high viscosity, viz. formic acid relative viscosity in the range 70100, and use of spinnerettes with three closely spaced capillary holes as disclosed in U.S. Pat. 3,216,186 of Nov. 9, 1965 to Opfell. These holes should have diameter of 0.018 inch to 0.022 inch giving an area for each group of three holes of about 7 10 to 12 10 sq. ins. Otherwise in such embodiment the operation is as described for the above example.

Another variant over the Opfell procedure which can advantageously be practiced with the present yarns is to use a larger draw pin or no draw pin and to omit the heater used by Opfell during drawing.

The resulting drawn yarn was supplied to a steam preheating chamber operating at 100 C. and then to the feed rolls of a stuifer box crimper. In Run A the gate weight on the stuffer box was 1.5 pounds and in Run B it was lb. The crimped yarn leaving the stuffer box was drawn (without completely straightening out the crimp) around a godet roll and then was passed to a pair of nip rolls through which it was fed at about 1.35 times the surface speed of the godet whereby the crimped yarn was straightened out and was stretched in the range of about 515% stretch beyond its fully straightened out length. From these nip rolls the yarn passed to a conventional winder operating with a tension of 175 grams per 1200 denier, 70-filament end of yarn.

Further details of the spinning and drawing conditions and performance, and the properties of the yarn 8 produced before and after crimping, are shown in the table below.

Although multilobal yarn, especially trilobal yarn as above described spun from a group of three closely adjacent holes is the preferred product of this invention, round yarn which has a crimp as above described is also within the ambit of this invention. Such round yarn can be spun from the above described melt through spinnerette holes of diameter about 14-22 mils, employing a spinning speed and stack draw down correlated to obtain undrawn denier per filament of about 30-100; and then processed to textured yarn by the general procedure above outlined.

TABLE Spinning and drawing conditions, performance, and physicals Example:

Pounds spun and drawn 390 Spinning performance (drips per 1000 lbs.)

(variable from 0 to 13) 3 13 Undrawn yarn properties- Uster, percent 13 Coefficient of filament denier variation 12 Denier (70-filament yarn) 4430 Drawn yarn properties Denier 1200 UE, percent (Instron) 30:2 UTS, g.p.d. (Instron) 50:0.1 Tensile modulus (g.p.d.) 1 50:2 Drawing performance- Wraps per pound 0.1 Breaks per pound 0.008 Spinning conditions- Exit polymer and block temp., C. 270 Extruder pressure, p.s.i.g 3000 Quench air, c.f.m., inlet/exhaust 70/63 Monomer exhaust, ins. water 4 Drawing conditions- Draw ratio 3.87 Heater temperature, C. 185 Textured yarn physical properties Crimps per inch 10 Crimp elongation before boil, percent 9 Crimp elongation after boil, percent 20:3 1 Slope of the first linear portion of the stress-strain curve (Instron) X 100.

Crimped yarn produced as above with the trilobal cross section of Opfell U.S. Pat. 3,216,186 has certain advantages in carpet over other trilobal yarns, in particular better resistance to fading upon exposure to ozone.

Crimped yarn of the Opfell cross section was employed in the production of tufted carpet samples. In standard tests, these samples showed excellent pattern definition, especially under humid conditions, and superior resilience together with satisfactory softness.

When this crimped yarn was twisted (4S-4Z) and the twist was heat set (steam at 15 p.s.i.g.) and the resulting yarn was employed to produce a cut pile carpet, the resulting carpet showed a pleasing velvety sheen.

A tufted loop pile carpet twisted 2S-2Z from 1200 denier 70-filament crimped yarn as above described having the trilobal cross section of Opfell U.S. Pat. 3,216,186 was found to approximate closely the characteristics of wool carpets.

The carpets produced from the above yarns showed good dyeability, especially with disperse anthraquinone dyes, and had good dye uniformity. The cover was exceptional; and in all respects these carpets were of high quality.

We claim:

1. A process for producing textured yarn which comprises:

(a) extruding through a multihole spinnerette a molten dispersion of polyester in a fiber-forming polyamide in weight proportions of :10 to 60:40 of polyamide: polyester to form a multiplicity of filaments, each filament being formed from an extrudate hole providing a capillary area of 7 l0f to 12x10 square inches;

(b) attenuating the filaments, while in molten condition, by a stack draw down of about 70 to 120; drawing said filaments after solidification to a draw ratio between about 3.5 and :1;

((1) crimping said drawn filaments at an average of at least about 8 crimps per inch; and

(e) fully straightening out and stretching the crimped yarn by at least about 5 percent beyond said straightened-out length.

2. The process of claim 1 further characterized by imparting to the drawing filaments about 8 to 17 crimps per inch in a hot zone, cooling said crimped filaments and stretching said cooled filaments about 5 to 15 percent beyond their straightened-out length.

3. The process of claim 1 wherein the crimping and stretching operations are correlated to confer crimp elongation off the package not above percent while maintaining crimp elongation after boil in the range between and 40 percent.

4. The process of claim 3 wherein the polyester is polyethylene terephthalate and the polyamide is poly-e-caproamide.

5. The process of claim 4 wherein the polycaproamide has a relative viscosity in aqueous 90 percent formic acid in the range of 50 to 100 by ASTM Test D-789-62T and has about 5 to milliequivalents of primary amino end groups per kilogram of polycaproamide.

6. The process of claim 5 wherein the filaments are formed from a group of three closely spaced capillaries to produce a multilobal cross section.

7. The process of claim 6 wherein the filaments are extruded into a quiescent atmosphere maintained at a temperature of about 320 to 380 C. at a distance about onehalf inch below the spinnerette.

8. The process of claim 2 wherein the crimping is effected in a stuifer-box crimper.

9. The process of claim 3 wherein the textured yarn is cut into staple fibers and spun into a yarn suitable for tufting.

10. The process of claim 3 wherein the textured yarn is tufted to form a pile article.

References Cited UNITED STATES PATENTS 3,143,784 8/ 1964 Scott. 3,361,859 1/1968 Cenzato. 3,382,305 5/1968 Breen. 3,399,108 8/1968 Olson. 3,447,308 6/1969 Fungijin et al. 3,470,686 10/1969 Fleming et a]. 3,489,832 7/1970 Bruton et a1.

DONALD J. ARNOLD, Primary Examiner J. H. WOO, Assistant Examiner US. Cl. X.R.