GB2142662A - Preparing multifilament yarn for windings - Google Patents

Abstract

The invention concerns a method of preparing windings of continuous multi-filament yarn of polycapronamide (Nylon 6) by high speed spinning. and windings obtained thereby for direct application to weaving. The method comprises the steps of extruding the polymer in the molten state, cooling the filaments by blowing, dressing and yarn winding, and is characterized in that during the cooling step, and hence simultaneously with dressing or immediately before or after it, the yarn is caused to absorb an amount of water, that the yarn is cohesioned pneumatically to a number of interlacings in the 5 to 30 per meter range, and that following the cooling step and up to the time of winding the yarn is kept in an environment at no less than 50% relative humidity and temperature in the 20 to 40 DEG C range.

Description

SPECIFICATION A Method of Preparing Poiycapronamide Yarn Windings, and Windings Obtained Thereby This invention relates to a method of preparing polycapronamide (Nylon 6) yarn windings by high speed spinning, to be used without further treatment for weaving purposes, as well as a yarn and windings obtained thereby.

The yarns currently employed in weaving are obtained conventionally by a process consisting of spinning the yarn melt, i.e. extruding the yarn in the molten state, cooling, and then stretching the yarn, which step in the instance of polyamides is usually performed in the cold condition, stretching being carried out either continuously to the extrusion step or in the course of a subsequent separate step.

Spinning is performed at a pick-up rate, for example, of about 600-1200 m/min, to obtain an unoriented yarn, orientation being imparted through the subsequent stretching step.

It is known to spin various synthetic yarns, including polyamides, at such a speed as to impart a degree of orientation thereto. Thus, pre-oriented, that is partially oriented, yarns are obtained a typical application wherefor is feeding into texturing processes, stretching being in fact completed in the course of the texturing process. It is a known fact that the orientation achieved in spinning is the more pronounced the higher is the spinning rate.

Consequently, manufacturers have long been trying to obtain directly during spinning, without stretching, yarns suitable for use in weaving as they are, without any further stretching thereof, whether carried out as a separate step or concurrently with some other step such as texturing. In theory, one would be led to think that by suitably increasing the spinning rate one would arrive at so enhanced an orientation as to impart the yarn with similar properties to those of a fully stretched yarn, thus making it suitable for direct use in weaving. Theoretical possibilities of this kind are pointed out in the pertinent literature, and in general spinning rates of 5000 m/min above are indicated. Below this rate-according to prior know-how-a degree of pre-orientation is achieved which requires additional stretching.

However, such theoretical possibilities have never been turned into industrial reality because it had been impossible to obtain a yarn winding which was suitable for direct application to weaving.

That application involves of necessity, as is to be expected, certain mechanical characteristics of the yarn which make it capable of withstanding without modification, and specifically without local modifications which vary from one spot to the next, the mechanical stresses brought about by the weaving operation, which are specially high with modern looms. Additionally to the above, it is required that the yarn winding resulting from the high speed spinning process be suitable for unwinding to provide a feed into a weaving process, which process may be carried out in accordance with different methods, depending on the loom types and the specific intended use of the yarn- namely, to provide a weft, warp, or knitting yarn.

Specified hereinafter will be those critical characteristics to be exhibited by a winding of this type in order for it to be industrially usable; it will be sufficient to mention here that no teachings have ever been provided by the prior art which may secure them.

Accordingly, it is an object of this invention to provide a manufacturing method which affords the achievement of polycapronamide (Nylon 6) yarn windings through a high speed spinning process, which windings can be used directly to feed into weaving steps, the yarn itself having desired mechanical properties and the winding having the required physical and morphological characteristics which it can retain through the conditions involved in its storage, transportation and handling, up to the time of weaving.

This invention specifically relates to polycapronamide, since the characteristics of the various synthetic polymers are markedly different as is different their behavior against the variables which affect the method being considered, thereby the behavior of any of them can provide no useful teachings for the treatment of another polymer, at least as far as such critical and sophisticated methods wherein so many critical variables come into play are concerned as are high speed spinning methods for obtaining a yarn which be suitable for use as it is.Thus, an applicable method to polycapronamide (Nylon 6) may not be equally applicable to polyhexamethylenedipamide (Nylon 66), and vice versa, in spite of the fact that both these polymers belong to the same class of polyamides and are, from the molecular standpoint, the linear synthetic polymers which are more closely analog to each other among those utilized in the industry.

Before the method of this invention is outlined, those characteristics should be singled out as must be exhibited, on one hand, by the-yarn, and on the other hand, by the winding, while leaving out those to be normally achieved in the course of a correctly conducted process, depending on the correct quality of the base polymer, correct performance of the extrusion step, efficiency of the picking-up units, and so forth.

Thus, the yarn for direct use in weaving should exhibit adequate mechanical strength when strained to the end of the elastic deformation region of its elastic (tension-elongation) curve. As is known, the tension-elongation curve has an initial portion which is ideally rectilinear and forms with the abscissae axis and angle whose tangent defines the elastic modulus of the yarn (or any other elastic material being considered). At the end of the appreciably rectilinear portion of the tension elongation curve, the elastic behavior proper ceases to exist and the deformation becomes a plastic, non-reversible one. It is customary to call the transition point "yield point". "Yield tension" will be called the tension which corresponds to this point, and which is identified on the graph by the ordinate of the point (see Figure 3).Instead of expressing it-as would be physically more correct to do-in units of force per units of cross-section, it is more convenient in the textile industry to state it as grams per denier, denier expressing, of course, the yarn cross-section. With these provisos, the yarn achieved by high speed spinning should have a yield tension equal to or exceeding 0.5 g/den. As for the rest, it should have the sufficient characteristics required in the textile art for polyamide yarns, as are well known to the person skilled in the art.

A yarn winding meeting the aforementioned requirements should, to be suitable for direct use in weaving, also be possessed of the following morphological and physical characteristics.

1) The winding must have a compression strength in Shore degrees which falls within a certain range and is appreciably uniform, uniformity being assessed through a statistical evaluation of measurements taken at various points on the winding as specified hereinafter.

2) The winding should not deviate beyond a given maximum from its ideal configuration, which is normally a cylindrical one but may be on occasions conical or crowned, and so on, such deviations being also assessed as specified hereinafter.

3) It should show no exteriorly detectable morphological irregularities, in particular across the two flat faces which delimit its two ends, such irregularities being mainly the presence of rectilinear yarn segments, i.e. segments lying along a chord and not along the yarn circular path, and loops or comparable protrusions from the ideal surface which delimits the winding, in particular at the two ends where said ideal surface is significantly flat.

4) It should retain the characteristics 1), 2), and 3) above in all the conditions to which it may be subjected from the time it is formed to the time when it is used, and which are in general beyond the winding manufacturer's control, thereby such characteristics should not be lost in the conditions of temperature and humidity whereto the winding may be subjected during storage for an extended period of time, during transportation and handling, as the result of mechanical stresses, the behavior of the yarn from this point of view being assessable by checking in standard conditions as specified hereinafter.

5) It should exhibit an adequate "unwinding capability", to be evaluated as specified hereinafter.

As for compression strength (1), this is measured in Shore degrees by means of a Type A hardometer in conformity with the ASTM D 2240 standard. Measurements are taken along 4 generatrices of the externai lateral surface of the winding extending at 900 to one another, the measurements being taken along each generatrix at 20 mm intervals; the first and last measurements should be taken at no less than 1 5 mm from the winding ends.Windings with a given compression strength are said to be "uniform" when each measurement as taken in the manner just described, falls within a range of plus or minus 2.5 Shores across ideal mean values in the 40 to 500 Shore, and when the compression strengths of the two regions at the winding ends, set at a distance apart from the edges smaller than 15 mm, do not exceed by more than 250 Shore the mean of the previously determined values.

As for the characteristic (2), reference can be had to Figure 1 herewith, which shows a half axial section through possible windings, the full line 1 denoting the ideal cylindrical axial half-section, and the dash line 2 representing some possible configurations for non-ideal winding axial half-sections. In the instance of ideal cylindrical configuration windings, any deviations should fall within limits such that the diameter pi dimension is at any point i along the axis in the following range: oi=oiO.02d where, o is the diameter of the ideal cylindrical winding; and that each height measurement Hj, taken at any point j along the diameter, falls within the following range: Hj=Ht12 mm where, H is the height of the ideal cylindrical winding.

As for the characteristic (3), visual assessment is resorted to in conformity with a procedure currently applied in the textile industry.

As for the characteristic set forth under (4) above, the yarn windings are subjected to a test consisting of holding them in a close apparatus and known climatic conditions for a preset time duration, preparatory to a successive series of tests, and determining at the end of each residence time the compressive strength and yield tension values. Five tests a-e are carried out, which consists of holding the yarn in the following conditions: (a) for 120 hours at 21 0C and 65% relative humidity (R.H.) (b) for 120 hours at 21 0C and 35% R.H.

(c) for 120 hours at 21 OC and 90% R.H.

(d) for 120 hours at 450C and 70% R.H.

(e) for 120 hours at 300C and 40% R.H.

Compressive strength and yield tension from tests (b) to (e) should show no deviations in excess of +7% for compressive strength and + 10% for yield tension, from the data found with the standard or reference test (a).

As for the characteristic (5), a yarn from the according to this invention, after successfully passing the "constant characteristics" test described hereinabove, is subjected to an unwinding test, as illustrated in Figure 2, which is directed to assessing the uniformity of the unwinding tension in the anticipated conditions of use for weaving.

Making now reference to Figure 2 of the accompanying drawings, a yarn from a winding (A) is passed through a pair of eyeled yarn carrier 3 and 3', set at 50 cm apart, the first whereof should be located 20 cm from the upper edge of the winding. Upon leaving the second yarn carrier, the yarn is caused to follow a free path 4, 40 cm long, before it is passed through a pair of yarn carrier 5, whence it is led horizontally to a first idle pulley 6 from where the yarn travels to a pin 7 having a 30 mm diameter.The yarn is passed around said pin at a 1800 angle, and after passing around a second idle pulley 8 reaches the pulling device, which comprises a roller 9 having a 160 mm diameter around which are set, as deflected by an idle roller 10 having a 20 mm diameter, four full coils or turns, and whence the yarn emerges to be thrown off by means of a suitable air ejector (E) of adequate capacity, of a type normally employed in the textile industry. Tension in grams is measured by inserting a suitable gauge (M). All the yarn carrier fingers, pulleys, and the pin are of sintered alumina having a surface roughness of, Rq=25=OB3 microns The test is carried out at a yarn entrainment speed by the pulling device which is equal to 950 m/min.At the beginning of the test, the relative position of the pair of yarn carriers 5 is adjusted such that the reference tension for a given yarn with a set denier is equal to 0.45 g/den.

With respect to the cited reference value, during the unwinding test, the tension recording will show both instantaneous (peak tension) variations, designated Ap, and long duration ones, designated At. A yarn winding is said to have a normal "unwinding capability" when throughout the unwinding test excepting for the unwinding of the last yarn layer having a thickness of approximately 0.2 mm and lying in direct contact with the coning support, the peak tensions and mean tension do not deviate by plus or minus 18% (Ap=+18%) and plus or minus 9% (At=+9%), respectively, of the basic 0.45 g/den tension.

Accordingly, an object of this invention is to provide a method of preparing a continuous multifilament yarn winding which has all of the aforementioned characteristics.

A further object of the invention are yarns and windings obtained with the above method.

The method of preparing continuous polycapronamide (Nylon 6) multi-filament yarn according to this invention comprises the steps of extruding the polymer in the molten state thereof to form filaments, cooling the filaments by blowing, dressing thereof, and winding the multi-filament yarn in the desired winding form, the method being characterized in that: (A) during the cooling step said yarn constituting said windings is caused to absorb an amount of moisture, said blowing step being carried out by means of a fluid having a relative humidity content other than zero, at a temperature in the 200C to 400C for a time duration ranging from 0.010 to 0.045 seconds; (B) simultaneously with said dressing, or immediately before or after it, the yarn is caused to absorb a further amount of water at a temperature in the 200C to 400 C; (C) said yarn is cohesioned pneumatically to have a number of interlacings in the 5 to 30 per meter range; and (D) after said cooling step and up to the time of winding, said yarn is held in an environment having a temperature level in the 200C to 400C and relative humidity of no less than 50%, it being intended that such humidity and temperature characteristics exist in the near proximities of the yarn, the rest of the environment, even from a very short distance from the yarn, being optionally entirely or in part at different temperature and humidity conditions.

As mentioned, the yarn is cooled by blowing a fluid medium such as air, nitrogen, and the like, at a relative humidity in the 45% to 95% range. Preferably, the relative humidity of the cooling medium is in the 70% to 90% range.

Dressing of the yarn is carried out, as mentioned either in the form of a much diluted aqueous emulsion, at unusual values in the textile field and with a proportion of finishing agent in water ranging from 1% to 12% by weight, preferably from 3% to 9% by weight, or alternatively as two separated operations, the one of administration of dressing agent as it is or in a more concentrated emulsion, e.g.

of 40% to 60 of finishing agent in water, the other of administration of water, at a temperature in the 200C to 400C range in any order. The latter operation may follow or immediately preceed the dressing one. Preferably, the first operation would be that of administering water.

Preferably, a further characteristic is the application of a finishing dress having in addition to lubricating properties also sizing properties. Lubricating properties are determined by measuring friction between the varn and a metal surface whereacross it is sliding. Friction measurement means here a measurement of the frictional coefficient in accordance with the formula, 1 T, f=In a T where, a=yarn winding angle, a=1 800; T1=output tension, g; T2=input tension, T2=5 g.

The above frictional coefficient "f" is measured on a Rothschild F-meter R 1083 apparatus equipped with an R 1082 Integrator (also by Rothschild). The increased tension T, of the yarn is measured on the fly while being wound at an angle a of 1 800 around a sintered alumina bar having a diameter of 5 mm and roughness Ra=0.40 microns.

The cohesioning power, as evidenced by the handle compaction of the filaments which make up the yarn, which compaction is required both during the winding forming step and successive utilization steps in the course of processing, should be such that the yarn can withstand the stresses which it undergoes with the filaments that compose it, avoiding portions where the stress could be transferred onto the individual component filaments, which results in poor mechanical patterns and faulty fabrics owing to the presence of loops which, in the extreme, may even be broken filaments.

The cohesioning power is connected with the physical and chemical characteristics of the dressing oil which must have good thermal resistance when subjected to thermodressing processes, good imperviousness to water for use, for example, on water jet looms, and good scourability, and show no interference with subsequent dyeing processes. It should, moreover, impart a correct smoothness while retaining good cohesion capabilities to hold the individual filaments together which make up the yarn. Furthermore, in order to be usable in spindle spinning processes such as those illustrated herein, dressing compositions must have good imbibition properties and originate no gel formations within the tanks or feeding circuits to the spinning machine itself and/or on the dressing composition applicators and/or successive organs which the yarn may have to contact.Typical examples of dressing compositions which are suitable for use in this invention are mixtures in more or less varying proportions of the following components: medium viscosity mineral oils; esters of the

type, where R and R, are either the same or different from each other and comprise linear alkyl radicais, or preferably branched ones, containing 1 8 to 36 carbon atoms; anionic antistatics, sulphonates having imbibing properties; oxyethylated saturated fat acids with emulsifier functions, having a molecular weight in the 400 to 1000 range; modified silicone oils having lubricating properties; ethylene oxide and/or propylene oxide condensates having a molecular weight in the 500 to 2500 range; sodium or potassium salts of linear or branched chain acids, and so forth.

The yarn is further cohesioned pneumatically until it shows a number of interlacings ranging from 5 to 30, depending on applicational requirements.

The number of interlacings or knots is measured with a method based upon the use of a suitably shaped hook having the same weight as the filament-denier of the yarn being analyzed. The hook is passed between the yarn filaments, the yarn having a length of 100 cm and being tied to a vertical rod under a 0.2 g/denier tension; the hook when released will slide along the yarn until it meets a knot or interlacing which stops it. The process is continued to obtain 50 readings, and the number of knots is related to the 100 cm yarn length.

Beside the method features outlined hereinabove, it will be apparent that the spinning and winding operations should be performed in agreement with accepted practice in the prior art. In particular, the winding assembly should be suitable for the application, should not subject the yarn to excessive or excessively varying tensions, in particular at the winding reversal points, and the winding operation should be carried out at an appropriate tension for the particular yarn being processed and for the winding assembly employed. All these conditions are well known to the skilled persons in the art and regularly applied in spinning and winding operations according to correct prior practices.

The polymer used for spinning is essentially a standard polymer obtained with normal prior methods, which is characterized, however, by an inherent viscosity in the 2.4 to 3.2 range. Lower inherent viscosities, such as have been proposed sometimes in an attempt to at least attenuate those problems which this invention fully solves, have the disadvantage of resulting in a yarn with less than fully satisfactory qualities, and an advantage of this invention is indeed that of eliminating the need for lower viscosities than those otherwise optimal.

With the aforementioned polymers and through this invention, windings can be obtained at high rates which are directly applicable to weaving processes and have the following characteristics: - yield tension above 0.5 g/den; - compressive strength in the 40 to 500 Shore range and substantially uniform, that is with deviations below +2.50 Shore, excepting at the winding ends, where the allowable deviation is +250 Shore; - substantially ideal configuration of the winding, normally a cylindrical one, with deviations in the order of 2 percent in diameter and 12 mm in height; - a winding substantially free of morphological irregularities, such as broken filaments, rectilinear yarn segments, loops, bights, or other protrusions; - constant characteristics in changing climatic conditions during storage and transportation:: +7% deviation in compressive strength, and + 10% deviation in yield tension; - "unwinding capabilities": optimal for weaving processing, i.e. with instantaneous deviations from the tension reference value Ap=I 18%, and long term deviations from the reference value, At=+9%.

The invention will be more cleary understood from the following description of some embodiments thereof, with reference to the accompanying drawings, where: Figure 1 is an axial haif-section view through possible windings according to the invention.

Figure 2 illustrates the apparatus used for the unwinding tension uniformity tests; Figure 3 shows the elastic curve of the yarn; and Figures 4 and 5 show schematically a side and front view, respectively, of the device for spinning and picking up synthetic multi-filament yarns.

With specific reference to Figures 4 and 5, the numeral 11 generally designates a spinneret delivering individual filaments, indicated at 12.

The filaments 12 are cooled at the position 13 by a cooling fluid blown into the device through specially provided channels 1 4.

At the end of the blowing area 13, the path of the yarn is unrestricted through the spinning environment, which is maintained in the conditions specified hereinabove. Preferably, the yarn is kept, up to the time of winding, in an environment having a relative humidity in the 60% to 90% range, at a temperature in the 20 to 400C range.

The reference numeral 1 5 designates two finishing agents and/or water admitting devices. Such devices may be both fed with finishing liquid in an aqueous emulsion, or alternatively, they may be fed respectively with water and finishing agent in the form of an as-it-is finishing agent or concentrated aqueous emulsion, as mentioned hereinabove already. The yarn is then channeled, preferably by means of a fairleading tube 25.

The elements just described define the so-called spinning area A of the apparatus.

The reference numerals 1 6 and 17 schematically designate two cups or yarn deflectors. The provision of such members, 1 6 and 17, is not strictly required, since it is also possible to work without them, using the so-called direct spinning method.

The numeral 18 designates a device operative to provide interlacing of the yarn to impart a set number of knots thereto.

The yarn carriers 1 9 and 20 function to control the path selected for the filament bundle flowing therethrough.

The traversing yarn carrier 21 is normally a part of the so-called pick-up assembly or winding assembly, generally indicated at 30 and comprising additionally the reel 22, translating roller 23, and possibly the complementary roller 24, if any.

The cups 1 6 and 17, the interlacing device 18, yarn carriers 19 and 20, and winding assembly 30 are a part of the pick up winding area B of the apparatus shown.

Finally, Figures 4 and 5 show the three heights HX, H2 and H3 which represent, respectively, the distance from the spinnerets plane to the first finish intake member or, as mentioned, of water (H1), the distance between said member and the point where the yarn is passed into the area B, which has been called the winding area (H2) and the distance between the latter point and the axis of the reel in the winding assembly (H3).

The method of this invention may be implemented on apparata whose dimensions may deviate from the so-called "traditional" ones (long spinneret-pick up path) to the so-called "compact" ones (short spinneret-pick up path), the three heights H1, H2 and H3 having the following dimensions: H,=l 00--1 50 cm; H2=90-580 cm; and H3=90-220 cm; the sum H,+H2 being equal to at least 240 cm.

The following examples illustrate this invention without restricting, however, its scope.

EXAMPLE 1 A polymer in granules of dull polycapronamide (Nylon 6), i.e. containing as the opacifier an amount of TiO2 equal to 0,35% by weight, previously dried to a residual humidity content equal to 0.065%, at a relative viscosity of 2.6, has been spinned by means of an electrically heated tube. That molten polymer has then been fed to metering pumping devices, and then filtered and extruded through a spinneret having 18 circular holes. From the tube outlet to the spinneret, the polymer has been kept at a temperature of 2580C by means of a diathermal fluid.

The molten filaments exiting the spinneret have been cooled by blowing air at a temperature of 300C and at 80% relative humidity (R.H.) The filaments were subsequently finished by passing them onto drilled yoke yarn carrier, to which an emulsion was admitted which comprised water and oil in the 97:3 ratio by weight. The distance H, from the spinneret plane to the first finishing device was 150 cm.The finish oil was comprised of the following mixture (formulation F1): - approximately 35 parts by weight of mineral oil having a viscosity of 7 cSts at 40 or; - approximately 25 parts by weight of ole 1 laurate: - 5 parts dioctyl sodium sulphosuccinate; - 5 parts petroleum sulphonate; - 1 5 parts by weight of a condensation product of nonylphenol with 4-5 moles ethylene oxide; - 10 parts by weight of condensation products of hydrogenated castor oil with 6-9 moles of ethylene oxide (EO); - 5 parts by weight of silicone oil modified with sulphonic groups.

The filaments were then transferred to the winding area B, under protection by a fairleading tube.

The distance H2, from the first finishing station mentioned above to the end of the fairleading tube (i.e.

the end of the spinning area A or inlet to the winding area B) was 280 cm.

The filaments were then subjected to an interlacing treatment in a device fed with air at a pressure of 3.5 ates and then picked up directly, i.e. without any intermediate deflection and/or pulling devices (cups).

The pickup assembly was operated at a speed of 3800 m/min. The distance H3 between the end of the fairleading tube and the axis of the reel in the pick-up assembly was 190 cm.

The thermal hydrometric conditions of the areas A (spinning area) and B (winding area) were as follows: AREA A: 22 OC and 70% R.H. AREA B: 220C and 65% R.H.

The processing conditions are reported in Table I, column 1.

A winding is obtained which has the characteristics detailed in Tables Il-VIl.

EXAMPLES 2-16 Similarly to Example 1, further yarn winding have been prepared in the processing conditions specified in Table I, to obtain windings whose characteristics are shown in Tables lI-VIl.

The columns 12 to 1 6 constitute reference examples, wherein at least a part of the processing conditions do not fall within the limits of this invention.

In Examples 3,5,6,7,9 and 12, the finishing oil comprised the following mixture (formulation F2): - approximately 30 parts by weight of isoterdecyl stearate; - 20 parts by weight of a condensation product of hydrogenated castor oil with 6-9 moles EO; - 30 parts by weight of polyoxyethylene and polyoxypropylene glycol condensates having a viscosity of 180 cSts at 20 C; - 20 parts by weight of potassium soaps of isostearic acid.

In Examples 10, 11 and 13, the finishing oil comprised the following mixture (formulation F3): - 60 parts by weight of isobutyl stearate; - 10 parts by weight of dioctyl-sodium-sulphosuccinate; - 1 5 parts by weight of a condensation product of nonyl-phenol with 4-5 moles ethylene oxide; - 10 parts by weight of potassium soaps of isostearic acid: - 5 parts by weight of silicone oil modified with sulphonic groups.

In Examples 9, 10 and 13, spinning was carried out with intermediate deflecting devices (cups) prior to picking up.

TABLE I

Example 1 2 3 4 5 6 7 8 Polymer(Nylon 6) 2.60 2.63 3.1 2.61 2.63 2.40 2.63 2.61 viscosity H2SO4 Opacifier % (TiO2) 0.35 0.00 0.35 1.50 0.35 0.00 1.50 0.35 Polymer residual 0.065 0.064 0.064 0.066 0.065 0.066 0.063 0.061 humidity (%) Spinning t ( C) 258 255 283 264 260 250 264 258 Spinneret hole No. 18 18 18 28 12 12 10 18 Individual filament type Circular Circular Circular Circular Circular Circular Circular Circular of cross-section t ( C) 30 34 30 30 26 36 38 26 Blowing R.H. (%) 80 72 75 70 80 75 60 75 Finish 1 E E E H2O E E E H2O Finish 2 E E E E E E E O Finishing Oil type F1 F1 F2 F1 F2 F2 F2 F1 Water/oil in the emulsion 97:3 91:9 93:7 60:40 97:3 95:5 90::10 H1 (cm) 150 140 140 100 120 140 135 110 H2 (cm) 280 90 290 330 310 290 295 300 H3 (cm) 190 130 190 190 200 200 200 190 TABLE I (Continued)

Example 9 10 11 12 13 14 15 16 Polymer (Nylon 6) 2.63 2.60 2.61 2.68 2.63 2.60 2.62 2.64 viscosity H2SO4 Opacifier % (TiO2) 0.00 0.35 0.35 1.50 0.00 0.35 0.35 0.35 Polymer residual 0.062 0.063 0.062 0.065 0.064 0.063 0.065 0.063 humidity (%) Spinning t ( C) 256 255 256 262 255 255 257 256 Spinneret hole No. 12 18 12 12 12 18 12 18 Individual filament type Triangular Circular Circular Circular Triangular Circular Circular Circular of cross-section t ( C) 38 26 26 26 38 30 26 38 Blowing R.H. (%) 75 75 85 44 27 30 35 38 Finish 1 E E E E E E E H2O Finish 2 E E E E E E E E Finishing oil type F2 F3 F3 F2 F3 F1 F1 F1 Water/oil in the emulsion 94:6 92:8 99:1 90:10 92:8 90:10 91:9 50::50 H1 (cm) 150 130 100 130 130 120 120 120 H2 (cm) 280 300 330 300 300 310 310 310 H3 (cm) 190 190 190 190 190 200 200 200 TABLE I (cont.)

Example 1 2 3 4 5 6 7 8 Interlacing air 3.5 2.8 3 2.4 7 7 7 2.8 pressure (ate) Deflecting cups NO NO NO NO NO NO NO NO Pick-up speed (m/min) 3800 3800 4000 3800 4500 3800 3800 3800 t ( C) 22 21 21 21 22 21 21 21 Conditions area A R.H. (%) 70 65 70 70 70 70 60 72 t ( C) 21 21 22 22 22 21 21 22 Conditions area B R.H. (%) 70 65 70 65 70 70 60 71 Count (denier) 70 70 70 100 40 40 40 70 TABLE I (cont.)

Example 9 10 11 12 13 14 15 16 Interlacing air 7 8 7 8.8 7 4 4.5 3.8 pressure (ate) Deflecting cups YES YES NO NO YES NO NO NO Pick-up speed (m/min) 3800 3800 5000 3800 3800 3800 4500 4000 t ( C) 22 22 22 21 21 23 23 24 Conditions area A R.H. (%) 70 70 74 44 42 40 40 45 t ( C) 22 21 20 22 21 20 20 20 Conditions area B R.H. (%) 69 68 73 38 38 39 40 39 Count (denier) 40 70 40 40 40 70 40 70 LEGENDA: Finish: E+Emulsion H2O=Water O=Finishing oil TABLE II

Example 1 2 3 4 5 6 7 8 Count/Filaments (denier/No.) 70/18 70/18 70/18 100/28 40/12 40/12 40/10 70/18 Yield tension (g/den) 0.52 0.56 0.5 0.58 0.6 0.58 0.55 0.62 Konts (No./m) 8 6 7 9 16 24 17 9 Finishing oil on 1.1 1 0.9 1.2 1 1 0.9 1.2 the yarn (%) Winding compressive Uniform Uniform Uniform Uniform Uniform Uniform Uniform Uniform strength Winding regularity of Regular Regular Regular Regular Regular Regular Regular Regular configuration Internal morphological Regular Regular Regular Regular Regular Regular Regular Regular regularity Characteristics constancy YES YES YES YES YES YES YES YES Unwinding test + + + + + + + + Bobbin height H (mm) 110 110 110 170 120 120 120 110 Diameter (mm) 320 320 320 280 340 340 340 320 Frictional coefficient f 0.44 0.40 0.36 0.42 0.37 0.36 0.35 0.39 ' TABLE II (Cont.)

Example 9 10 11 12 13 14 15 16 Count/Filaments (denier/No.) 40/12 70/18 40/12 40/12 40/12 70/18 40/12 70/18 Yield tension (g/den) 0.62 0.58 0.64 0.46 0.44 0.42 0.46 0.4 Knots (No./m) 21 26 12 15 22 6 9 10 Finishing oil on 1.3 1.1 0.85 1 1.3 0.7 1.1 1.2 the yarn (%) Winding compressive Uniform Uniform Uniform Non- Non- Nonstrength uniform Uniform uniform uniform Uniform Winding regularity of Regular Regular Regular Regular Regular Regular lrregular lrregular configuration Internal morpholiogical Regular Regular Regular Regular Regular lrregular lrregular Regular regularity Characteristics constancy YES YES YES NO NO NO NO NO Unwinding test + + + - - - - Bobbin height H (mm) 120 170 120 120 110 170 110 170 Diameter (mm) 340 280 340 340 320 280 320 280 Frictional coefficient f 0.44 0.41 0.36 0.38 0.44 0.44 0.41 0.43 TABLE III Compressive Strength (Shore degrees)

Example 1 2 3 4 5 6 7 8 Reading at 1/2 h 44 44 46 51 47 48 46 47 Reading at 1/6 h 46 46 48 53 46 47 47 46 Reading at 1/3 h 45 45 44 49 44 46 44 45 Reading at 2/3 h 45 45 45 48 45 45 45 44 Reading at 5/6 h 46 46 47 53 45 47 46 46 Reading 5 mm from 62 64 69 72 73 68 70 72 the upper edge Reading 5 mm from 64 62 72 70 71 70 72 70 the lower edge Assessment Uniform Uniform Uniform Uniform Uniform Uniform Uniform Uniform TABLE III (Cont.) Compressive Strength (Shore Degrees)

Example 9 10 11 12 13 14 15 16 Reading at 1/2 h 50 47 48 33 46 47 30 48 Reading at 1/6 h 52 48 47 32 47 48 35 46 Reading at 1/3 h 54 46 46 32 45 42 38 47 Reading at 2/3 h 52 45 44 36 46 43 31 45 Reading at 5/6 h 53 47 47 34 48 46 33 47 Reading 5 mm from 70 72 74 65 74 76 70 72 the upper edge Reading 5 mm from 69 74 72 65 79 75 72 78 the lower edge Assessment Uniform Uniform Uniform lrregular lrregular lrregular lrregular lrregular TABLE IV Regularity of onfiguration (mm)

Example 1 2 3 4 5 6 7 8 Dia. at 1/2 h 315 316 318 279 337 338 340 316 Dia. at 1/6 h 319 320 319 281 337.5 339 341 316.5 Dia. at 1/3 h 316 317 318 280 337 338.5 340.5 316 Dia. at 2/3 h 316 317 317 279 336 337 339 315 Dia. 5 mm from the edges 320 320 321 282 338 340 342 318 H at Dia. max. 111 112 110 170 121 119 120 110 H at Dia.=2/3 114 114 113 171 121 120 121 114 H at Dia=1/3 115 115 115 172 121 120 121 116 Assessment Regular Regular Regular Regular Regular Regular Regular Regular TABLE IV (Cont.) Regularity of configuration (mm)

Example 9 10 11 12 13 14 15 16 Dia. at 1/2 h 338 275 334 338 315 275 315 278 Dia. at 1/6 h 339 276 334 341 319 277 317 279.5 Dia. at 1/3 h 338 276 334 340 317 276 315 278.5 Dia. at 2/3 h 337 275 334 339 316 275 313 278 Dia. 5 mm from the edges 341 277 335 344 321 280.5 322 171 H at Dia. max. 120 171 120 120 111 171 109.5 171 H at Dia.=2/3 121 171 120 127 114 180 116 180 H at Dia=1/3 122 171 120 129 118 184 120 185 Assessment Regular Regular Regular Regular Regular Regular lrregular lrregular TABLE V External morphological irregularities

Example 1 2 3 4 5 6 7 8 Loops NO NO NO NO NO NO NO NO Broken filaments NO NO NO NO NO NO NO NO Stretched yarns NO NO NO NO NO NO NO NO Assessment Regular Regular Regular Regular Regular Regular Regular Regular TABLE V (Cont.) External Morphological lrregularities

Example 9 10 11 12 13 14 15 16 Loops NO NO NO NO NO YES YES YES Broken filaments NO NO NO NO NO NO YES YES Stretched yarns NO NO NO NO NO NO NO YES Assessment Regular Regular Regular Regular Regular lrregular lrregular lrregular TABLE VI Constancy of Characteristics

Test Ex.1 Ex.2 Ex.3 Ex.4 Ex.5 Ex.6 Ex.7 Ex.8 a 0.52 0.56 0.50 0.58 0.60 0.58 0.55 0.62 Yield b 0.55 0.58 0.52 0.59 0.61 0.59 0.58 0.64 tension c 0.50 0.54 0.50 0.56 0.60 0.56 0.53 0.61 (g/den) d 0.53 0.56 0.54 0.57 0.60 0.57 0.56 0.63 e 0.54 0.56 0.53 0.58 0.61 0.58 0.57 0.64 a 45 45 44 49 44 46 44 45 Compressive b 48 48 46 51 47 48 47 47 strength ( Shore) c 43 43 43 47 43 45 43 44 at 1/3 H d 46 46 47 50 46 46 46 46 e 47 47 47 51 47 47 47 47 a 45 45 45 48 45 45 45 45 Compressive b 48 48 47 49 48 48 48 47 strength ( Shore) c 44 44 43 46 44 45 46 43 at 2/3 H d 46 46 48 49 46 46 48 47 e 46 46 48 50 47 47 48 46 Assessment YES YES YES YES YES YES YES YES YES TABLE VI (Cont.) Constancy of Characteristics

Test Ex.9 Ex.10 Ex.11 Ex.12 Ex.13 Ex.14 Ex.15 Ex.16 a 0.62 0.58 0.64 0.46 0.44 0.42 0.46 0.40 Yield b 0.62 0.61 0.65 0.50 0.50 0.51 0.52 0.46 tension c 0.60 0.57 0.63 0.46 0.47 0.43 0.43 0.43 (g/den) d 0.62 0.60 0.63 0.52 0.53 0.54 0.51 0.50 e 0.63 0.60 0.64 0.54 0.54 0.55 0.53 0.51 a 54 46 46 32 45 42 38 47 b 56 49 48 41 52 48 45 50 Compressive strength c 53 46 45 35 44 42 37 42 ( Shore) at 1/3 H d 55 47 46 39 50 46 43 49 e 56 48 47 36 49 47 45 51 a 52 45 44 36 46 43 37 45 b 54 48 46 51 49 46 51 Compressive streingth c 53 43 43 33 42 40 38 43 ( Shore) at 2/3 H d 54 46 47 34 48 45 42 48 e 54 47 47 36 50 47 45 51 Assessment YES YES YES YES NO NO NO NO NO YES=Passes the test NO=Fails the test TABLE VII Unwinding Test

Example 1 2 3 4 5 6 7 8 Count (denier/ 70/18 70/18 70/18 100/28 40/12 40/12 40/10 70/18 No. filaments) Reference tension (g) 32 33 32 44 18 19 18 32 p (%) 18 16.5 15 18 14 13.5 16.1 17.9 t (%) 8.3 8 7.6 8.3 8.6 7.8 8.2 8.4 Assessment + + + + + + + + TABLE VII (Cont.) Unwinding Test

Example 9 10 11 12 13 14 15 16 Count (denier/ 40/12 70/18 40/12 40/12 40/12 70/18 40/12 70/18 No. filaments) Reference tension (g) 18 33 18 18 18 33 19 32 p (%) 16.8 17.3 15.4 21 15.6 20.1 22 25 t (%) 7.2 8.8 8 9.3 9.4 9 9.3 9.6 Assessment + + + - - - - +=Passes the test -=Fails the test

Claims (21)

1. A method of preparing windings of continuous multifilament yarn of polycapronamide (Nylon 6), comprising the steps of extruding the polymer in the molten state to form filaments, cooling the filaments by blowing. dressing and winding the multi-filament yarn comprised of said filaments to suit a desired unwinding form, and characterized in that:: (a) during the cooling step, said yarn is caused to absorb an amount of moisture, said blowing step being effected by means of a fluid having a relative humidity content other than zero, at a temperature in the 20 to 40 OC range, for a time period in the 0.010 to 0.045 seconds range; (b) simultaneously with the application of said dressing composition, or immediately before or after it, the yarn is caused to absorb an additional amount of water at a temperature in the 20 to 400C range; (c) said yarn is entwined pneumatically until a number of interlacings in the 5 to 30 per meter range is achieved; and (d)following said cooling step and until the winding step is initiated, said yarn is kept in an environment having a temperature of 20 to 4O0C and a relative humidity of no less than 50%, it being intended that such humidity and temperature conditions prevail in the immediate proximity of the yarn, the remaining portion of said environment, already at a short distance away from the yarn, being allowed to be entirely or partly in different conditions of temperature and humidity.

2. A method according to Claim 1, characterized in that the relative humidity of said cooling fluid is in the 45% to 95% range.

3. A method according to Claim 2, characterized in that the relative humidity of said cooling fluid is in the 70% to 90% range.

4. A method according to Claim 1, wherein said step (b) is carried out by applying on the yarn a diluted finishing dressing aqueous emulsion having a concentration of finishing agent in water in the 1% to 12% range by weight.

5. A method according to Claim 4, wherein the concentration of said finishing agent is in the 3% to 9% range by weight.

6. A method according to Claim 1, wherein said step (b) is carried out by separate application of water and finishing agent as it is.

7. A method according to Claim 1, wherein said step (b) is carried out by separate application of water and finish dressing in the form of a concentrated aqueous emulsion having a concentration of finishing agent in water in the 40% to 60% range by weight.

8. A method according to either Claim 6 or 7, characterized in that the application of said finishing composition follows the application of water.

9. A method according to Claim 1, characterized in that said step (d) is carried out while keeping said yarn in an environment having a relative humidity content in the 60% to 90% range.

10. A method according to any of the preceding claims, characterized in that the winding is wound in a coiled form.

11. A method of preparing windings of continuous multi-filament yarn of polycapronamide (Nylon 6), as herein described and illustrated.

12. A winding of continuous multi-filament yarns of polycapronamide (Nylon 6), suitable for direct use in a weaving process, characterized in that: (a) it comprises a yarn having a yield tension of no less than 0.5 g/den; (b) it has a high and uniform compressive strength; (c) it is free of significant deviations from its ideal configuration; (d) it retains the above properties in the storage and transportation conditions; and (e) has an optimum "unwinding capability".

1 3. A winding of continuous multi-filament yarns of polycapronamide (Nylon 6), suitable for direct use in a weaving process, characterized in that it is prepared with the method according to any of Claims 1 to 11.

14. A winding according to either Claim 12 or 13, characterized in that the mean value of said compressive strength falls within the 40 to 500 Shore range.

1 5. A winding according to Claims 12 to 14, characterized in that said compressive strength, as measured at any points on the lateral surface thereof excepting the ends, shows no deviations in excess of +2.5" Shore from said mean value, and that said compressive strength, as measured at said ends does not exceed said mean value by more than 250 Shore.

1 6. A winding according to either Claim 12 or 13, characterized in that it has a substantially cylindrical configuration, the diameter of each cross-section perpendicular to the axis of said cylindrical configuration showing no deviations in excess of +2% of the mean diameter, and any measurements of distance between the bases taken parallel to said axis show no deviations in excess of +12 mm from the mean value of the height of said cylindrical configuration.

17. A winding according to either Claim 12, 13 or 16, characterized in that it has no significant externally detectable morphological irregularities.

1 8. A winding according to Claim 17, characterized in that it includes no rectilinear, looped, or broken filament yarn segments.

19. A winding according to any of Claim 12 to 15, characterized in that it retains the compressive strength and yield tension within deviation limits of #7%, respectively * 10%, from values measured after a residence of 120 hours in an air environment at 21 C and 65% relative humidity, for a time period of at least 120 hours in an air environment at a temperature in the 20 C to 450C and relative humidity in the 35% to 90% range.

20. A winding according to either Claim 12 or 13, characterized in that it has an "unwinding capability" such that instantaneous and long term deviations from the reference tension value do not exceed + 18%, respectively +9%.

21. A winding of continuous multi-filament yarn of polycapronamide (Nylon 6), suitable for direct use in a weaving process, as herein described and illustrated.