WO2003064743A1

WO2003064743A1 - Yarn-production apparatus and method

Info

Publication number: WO2003064743A1
Application number: PCT/IB2003/000267
Authority: WO
Inventors: Paolo Bert
Original assignee: Tecnofil Srl
Priority date: 2002-01-29
Filing date: 2003-01-27
Publication date: 2003-08-07
Also published as: ITTO20020081A0; ITTO20020081A1

Abstract

An apparatus and method for producing a pseudo space-dyed yarn formed of at least two strands of filaments, wherein the at least two strands have differing visual appearances; the apparatus comprises: (A) a filament-forming means for producing strands of filaments by melt spinning (10) and stretching (12) them in an integral process; (B) a first entangling means (141; 142; 143) for separately entangling each os said at least two strands while still at an alevated temperature by a laterally impacting fluid having an elevated temperature; (C) a texturingzing means (16) for texturingzing said at least two strands at an elevated temperature; (D) a coling means for cooling said at least two strands to an ambient temperature; (E) a second entangling means for commonly entangling said at least two strands by a laterally impacting fluid having ambient temperature to obtain said pseudo space-dyed yarn; and(F) a winding means for collecting said pseudo space-dyed yarn obtained from said second entangling means.

Description

YARN-PRODUCTION APPARATUS AND METHOD

FIELD OF THE INVENTION AND PRIOR ART

This invention relates to an apparatus and a method for producing a pseudo space- dyed yarn.

"Space-dyeing" is a term used to refer to a prior art method of improving the appearance of yarns and involves application of differently colored spots to a yarn (also termed "effect yarn" or "fancy yarn"). Since this method tends to be relatively complicated and costly, various methods have been developed for producing multicolored yarns having a comparably vivid color appearance by entangling (also termed "interlacing", these terms being used synonymously herein), i.e. a yarn- processing step of wrapping or knotting the filaments about each other by mechanical means or by the use of jets of a pressurized fluid or gas, respectively.

Such methods are disclosed, for example, in US 5 804 115 (BASF Corporation), US 6 094 790 (Rieter AG) and US 6 240 609 (Prisma Fibers Inc) and the term "pseudo space-dyeing" is used synonymously herein with "mock space-dyeing" and "quasi space-dyeing". These known methods suffer from a limitation of the number of yarns that can be processed in a single plant and/or by a limited production speed. For example, the feed rate disclosed in the last-mentioned U.S. patent 6 240 609 is in the range of from about 400 to about 600 meters/minute (m/min) and, in any case below about 1000 m/min.

OBJECTS AND BRIEF DEFINITION OF THE INVENTION

US 5 078 773 (Filteco) - incorporated herein for all purposes by way of reference

- on the other hand, discloses method and apparatus means capable of simultaneously producing a large number of yarns, e.g. 16 or 32 yarns on a single machine at output speeds of typically in the range of at least about 1000 m/min and typically in the range of from about 1200 to about 2600 m/min and it would be highly advantageous - and is a primary object of the present invention - to use a yarn-producing plant of this type to produce pseudo space-dyed yarns in a more economical manner including the possibility of "retrofitting" existing machinery for continuous yarn production. Surprisingly, it has been found that these objects and further advantages can be achieved, according to a first embodiment of the invention, by an apparatus for producing a pseudo space-dyed yarn formed of at least two strands of filaments having differing visual appearances (e.g. differing color, texture or other properties that can be distinguished in the filaments that are used in a yarn); the apparatus according to the invention includes:

(A) a filament-forming means for producing the filaments by melt spinning in an integral process. Such means are disclosed, e.g. in the above-mentioned US 5 078 773 for simultaneous production of a plurality of filament strands wherein all filaments of each strand have substantially the same properties including appearance and filament characteristics. Typically, two or more separate extruders are used to extrude differently pigmented or dyed filaments via spinnerets into a vertical air shaft for solidification and subsequent drawing. Typically, filaments are extruded by means of at least two separate extruders, each producing filaments of a differing color, at a speed of at least about 400 meters per minute (m/min). Machines of this type are available commercially and will be discussed in more detail below;

(B) a first entangling means (or "entangler") for separately entangling each of the at least two strands while still at an elevated temperature by a laterally impacting fluid having an elevated temperature. Such entangling means are known in the art, e.g. as disclosed in US patent 4 965 916, DE 37 11 758 and EP 326 552;

(C) a texturizing means (or "texturizer") for texturizing each of said at least two strands at an elevated temperature. Such texturizing means operating with a jet of a fluid (liquid or gas) or by mechanical impacting, are known, e.g. from the patents mentioned above; generally, each strand is texturized by a separate texturizer but combining two or more strands in a single texturizer is not generally excluded;

(D) a cooling means for cooling said at least two strands to an ambient temperature; typically, such a cooling means is a conventional grooved and relatively slow moving roll for receiving the texturized strands emanating from the texturizer and for cooling it to ambient temperature (about 15 to about 30°C); (E) a second entangling means for commonly entangling the at least two strands . by a laterally impacting fluid having ambient temperature to produce the pseudo space- dyed yarn; and (F) a winding means for collecting the pseudo space-dyed yarn obtained from the second entangling means. Suitable winding means or winders operating at a speed of at least about 1000 m/min, and preferably up to about 2400 m/min, are well known in the art and are available commercially.

PREFERRED EMBODIMENTS AND DEFINTION OF TERMS

The term "about" preceding a numeric value (or range of values) given herein is intended to include the cited value with a deviation of up to 30% above and below the cited value.

The term "polymer" is intended to refer to macromolecular organic substances which are capable of forming monofilaments by spinning, e.g. by melt-spinning, solution-spinning or gel-spinning. Generally, such polymers are man-made and can be homopolymers, co-polymers obtained by co-polymerization and/or grafting, and mixtures thereof. Specific examples are polyalkylenes, such as polyethylene and polypropylene, polyesters, polyamides, polyacrylates and other polymers conventionally employed for production of yarns for various textile uses including carpets, furniture covers, bed or table cloth, upholstery, garments or garment linings, and other products including textile materials used in the manufacture of shoes. Recycled polymers of the thermoplastic type, such as recycled polyethylene, polypropylene and polyester are a preferred material for production of pseudo space- dyed yarns according to the invention, notably when the yarn is to be used in the manufacture of carpets. The terms "up-stream" and "down-stream" as used herein are relative terms and refer to a position closer to, or more removed from, the in-feed portion of the yarn- producing apparatus, i.e. the spinning section. For example, according to a first preferred embodiment of the present invention, the first entangler is arranged upstream of the texturizer and the subsequent cooling means while the second entangler is arranged downstream from texturizer and cooling means. This embodiment has the advantage that the filament strands entering the first entangler are still relatively warm so that less energy is required in the first entangling step. However, both the first and the second entangler can be provided, according to a second embodiment of the invention, downstream from the texturizer. While the advantage of energy conservation is lost in this embodiment, the advantage of retrofitting existing machinery for production of pseudo space-dyed yam is maintained for the large and wide roll plants explained in more detail below and used in a generally preferred embodiment of the invention.

Further, it should be noted that the terms "yarn" and "strand" as used herein both refer to a continuous structure composed of a plurality of monofilaments, the difference being one of a differing degree of entanglement in the sense that a strand will have little or no mutual entanglement, intertwining, twisting or the like of the essentially parallel filaments whereas a yam will show less or no parallel alignment of the filaments that constitute the yam.

Since the invention is directed to production of ya s from filaments of differing optical appearance, generally of differing colors, and since such difference is generated by separate extruders, the terms "strand" as used herein generally refers to a multiplicity of filaments of the same optical appearance while the term "yam" herein implies the presence of filaments from at least two optically differing strands.

The yam-producing machine of the type disclosed in US 5 076 773 is capable of producing simultaneously at least 6 yams, e.g. 8, 16 , 24, 32 or even 48 yarns, generally in a symmetrical assembly of two half-machines with rolls extending outwardly on each side as shown in Fig. 4A of the drawing US 5 076 773. Each side or "half-machine"

(arbitrarily termed "left" and "right" side) is capable of simultaneously producing from about 6 to about 24 yams, i.e. a total of about 12 to about 48 yarns with the "complete" or "doublesided" machine by spinning and drawing in an integral high-speed process providing for production rates in the range of from about 1000 to about 2000 m/min or more. Typical features of such a yam-producing plant include a vertical shaft to provide for a free path length of the filaments after emergence from the spinneret and prior to first contact with a mechanical filament-contacting means of at least about 2.5 meters, e.g. about 3-5 meters. Groups of extruded and solidified filaments are combined into strands which are then drawn in parallel arrays on a sequence of large and wide rotating cylinders or rolls having parallel axes of rotation to provide for a path length of frictional contact with the strands of from about 1000 to about 6500 millimeters (mm), preferably of from 1000 to 4000 mm and most preferably from 1500 to 3000 mm. At least about 50% and preferably 75 to 100% of the length of frictional contact is provided on a total number of from 2 to 6, preferably from 3 to 5 and most preferably 4 cylinders. Yarn-producing machines of this type will be termed "large and wide roll plants" hereinafter.

With such machines it is possible to resolve a main problem in any continuous production or treatment of filaments and yams, respectively, namely the need of maintaining continuous plant operation upon breakage of filament, strands or yams in an apparatus in which a very large number of yams is to be produced simultaneously.

To this end, "deviating devices" or "traps" are provided along the path of the yams, strands, or filaments which will trap and carry away the continuously supplied up-stream end portion of the yams, strands or filaments after a break, typically into a bin for recycling. Then, an operator supplied with a cutter and mobile suction device severs the filament, strand or yam at a point before its entry into the deviating device and proceeds to "draw" the broken filament strand down-stream and around or through any subsequent stages of the yarn-producing apparatus. For this reason, all portions of a yam-producing apparatus where breakage of filaments may occur must be easily accessible to allow repair of such breakage, and it is an essential advantage of the large and wide roll plants mentioned above that such easy access is provided in all portions of the drawing stage where the tendency to break is most pronounced as a result of the tension applied to the filaments. Thus, according to a second embodiment of the invention, the filament-forming means (A) of the apparatus defined above includes:

(Al) means for simultaneously extruding a sufficient number of filaments, e.g. at least 10 and generally from about 24 to about 96, typically with a denier of from about 1200 to about 6000, for forming the at least two strands into an essentially vertical air quenching zone for solidification of the filaments;

(A2) means for arranging the filaments so as to form a substantially planar array of the at least two strands in a parallel arrangement on a sequence of drawing rolls, preferably the rolls of a large and wide roll plant as defined above;

(A3) means for together pre-stretching the filaments by passing the strands, while maintaining them in the array, in frictional contact with peripheral surface portions of at least two rotating draw cylinder of the large and wide roll plant, each strand passing over the surface portions along a discrete path which is substantially defined by a plane intersecting perpendicularly with the parallel axes of rotation of the at least two rotating draw cylinders; each of the rotating draw cylinders having a diameter sufficient for providing a contact path length for said filaments of from about 1 meter to about 6 meters; and

(A4) means for passing the at least two strands while maintaining them in the array, in contact with peripheral surface portions of at least two additional rotating draw cylinders of the large and wide roll plant having axes of rotation parallel to the first and said second rotating draw cylinders for additionally stretching the filaments, each strand passing over the surface portions of the additional draw cylinders along a discrete path which is substantially defined by a plane intersecting perpendicularly with the parallel axis of rotation of the additional rotating draw cylinders, each having a diameter greater than about 300 mm.

According to a further embodiment, the present invention provides for a method of producing a pseudo space-dyed yam formed of at least two strands of filaments having differing visual appearances, comprising the steps of: (A) producing the filaments forming the at least two strands by melt spimiing and stretching them in an integral process;

(B) separately entangling each of the at least two strands while still at an elevated temperature by a laterally impacting fluid having an elevated temperature;

(C) texturizing the at least two strands by a laterally impacting fluid at an elevated temperature;

(D) cooling the at least two strands to ambient temperature;

(E) commonly entangling the at least two strands by a laterally impacting fluid to obtain the pseudo space-dyed yam; and

(F) collecting the pseudo space-dyed yam obtained from the second entangling step.

According to a further embodiment, the invention provides for a pseudo space- dyed yarn obtained according to the invention having periodically alternating sections with a length of between about 2 and about 20 mm.

In a yet further embodiment, the invention provides for carpets made from pseudo space-dyed yarns obtained according to the invention. BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be explained without limitation with reference to the enclosed drawings in which: Figure 1 is a diagrammatic view of a general first embodiment of an apparatus according to the invention; Figure 2 is a diagrammatic view of a modification of the apparatus shown in

Fig.l;

Figure 3 is a diagrammatic side view of a second embodiment of an apparatus according to the invention; and

Figure 4 is a diagrammatic view of entangled yarns to illustrate pseudo space- dyeing.

Apparatus 1 in Fig. 1 comprises a spimiing unit 10 producing three strands 101,102,103 each formed of a plurality of filaments. At least two strands have a differing optical appearance, typically by coloring the polymer composition that is extmded from an extruder through the orifices of a spinneret (not shown).

Filaments 101,102,103 enter into a drawing unit 12 where they are stretched for molecular orientation, preferably, but not necessarily, on a large and wide roll machine. Each strand 101,102,103 emanating from drawing unit 12 still at an elevated temperature typically in the range of from about 50 - 150°C is passed through a separate pre-entangler 141,142,143 where it is entangled or interlaced in a conventional manner by a laterally impacting gaseous or liquid fluid.

After interlacing or entangling, strands 101,102,103 are texturized by means of a fluid or by mechanical impact in a conventional texturizer 16. Preferably, one texturizer

16 each is used for each strand but strands, or strand portions, could also be combined prior to texturizing. When leaving texturizer 16, the texturized bulked strands are deposited in the grooves (not shown) of slowly rotating cooling drum 18 from which they are drawn off at production speed by means of roll 11. All strands that are to be used in a given yarn 17 (in this case three strands 101,102,103) are commonly fed into a second entangler or interlacer 15 operated in a conventional manner. Thereafter, entangled or interlaced yarn 19 is wound up in a conventional manner on a winder (not shown). The apparatus 2 illustrated in Fig. 2 operates in the same manner by producing three strands each in two spinning units 20, drawing them on the large and wide rolls of drawing units 22, entangling each strand separately in a separate pre-entangler 24 and texturizing each strand in a texturizer 26 with subsequent cooling on roll 28. However, according to Fig. 2, six pre-entangled and texturized strands are combined into yam 27 which is then fed into and through a common entangler 25 for producing a pseudo space-dyed yam 29.

Fig. 3 shows a diagrammatic side view of a large and wide roll machine 3 of the type disclosed in US 5 076 773 modified according to the present invention. From a spinning unit (not shown in Fig. 3) two groups 301, 302 of a multiplicity of filaments are produced typically for manufacture of 6 - 12 yams from each filament group 301, 302. Small feed rolls 311, 312, e.g. with a typical diameter of about 180 mm, serve to keep the melt emanating from the spinning unit under tension during solidification. Typically, rolls 311, 312 are operated at a speed of 300 m/min and filament groups are formed to constitute an array of strands, there being at least two groups of filaments of differing colors.

A trio of small-diameter rolls 320, 321, 322 is used to produce what is "called passive tension", i.e. the frictional resistance required for drawing. Rolls 323 and 324 are large-diameter rolls, typically with a diameter of about 500 mm, again operated at a relatively low speed for the frictional resistance required for drawing by means of large- diameter (typically about 500 mm) drawing rolls operated at incrementally increased peripheral speeds, say by increments of from about 50 to 100 m/min starting at 1000 - 1200 and ending at 1200-1400 m/min. As an example, roll 325 could be operated at a peripheral speed of 1000 m/min, with 1250 m/min for roll 326 and 1300m/min for roll 327. Preferably, all rolls 323, 324, 325 and 327 are heated as is conventional for filament production, e.g. to temperatures in the range of from about 80 - 180°C . As will be apparent to those experienced in the art, roll speeds and roll temperatures depend upon the processed polymer and are well-known to those experienced in the art, and the above values are given merely by way of illustration. Each filament strand is passed through a pre-interlacer or pre-entangler 34 which may be located either between rolls 326 and 327 (34a) or between roll 327 and upstream of texturizer 36 where the strands are bulked. Preferably, the pre-entangler or pre- interlacer is in position 34b while a conventional fine-tension adjustment device is provided at 34a.

Again, a cooling roll 38 is provided for cooling the pre-interlaced strands to ambient temperature, and a take-off roll 313 serves to collect the strand into yams which are then passed through the second entangler or interlacer 35 and via a take-off roll assembly 37 to a winder 39.

Two yarns 4a, 4b each obtained according to the invention by interlacing of three pre-interlaced threads are shown diagrammatically in Fig. 4. It is to be understood that the threads of a yarn obtained according to the invention are not side by side but interleaved. Now, assuming that each of the tliree threads of each yam 4a and 4b has a different optical appearance, e.g. is colored (in the sequence from left to right) yellow (Y), cyan (C) or magenta (M), it is apparent that a carpet made from a 4a type yam will exhibit an essentially uniform appearance due to the homogeneous overall distribution caused by the interlacing regularity of the loops in all sections 41a - 46a. In contrast, a 4b type yam will exhibit a marked pseudo space-dyed appearance because of the differing structure of the threads resulting form pre- interlacing of the strands that form the threads. For example, in section 42b of a type 4b yam the yellow (Y) thread is more apparent than the cyan (C) and magenta (M) threads while the yellow thread is less marked in sections 43b where cyan and magenta will dominate. In section 45b, in turn, all three colors will appear to be more pronounced than in sections 41b, 44b and 46b. The length of the sections shown in Fig. 4 may be uniform or may differ, preferably in the range from about 2 mm to about 20 mm.

The different degrees of interlacing of the strands or threads shown in the various sections of yarn 4b in Fig. 4 can be controlled by differing-in-time the interlacing effectiveness in the pre-interlacing step according to the invention. This can be achieved simply by controlling the flow of the fluid medium used in the pre-entangling step. For example, if the flow rate of the fluid is interrupted for a short period of time, no pre- entangling of the strand will occur. Thus, in order to obtain the yam structure of section 42b, the fluid stream acting upon the pre-entangler of the yellow yam is interrupted for a very short period of time, say a fraction of a second, while the fluid streams acting upon the cyan and magenta strand are at their normal level. To obtain the structure of section 43b, the entangling effectiveness of the pre-entanglers for the magenta and cyan strand is reduced or stopped briefly while the yellow strand is pre-entangled with normal effectiveness. In order to obtain the structure of section 45b, pre-entangling of all three strands forming the yam after the second entangling is interrupted or reduced in all pre-entanglers.

Control of pre-entangling by changing the entangling effectiveness by controlling the feed rate of the fluid, e.g. by means of a programmable controller, is known per se in the art and has been disclosed, e.g. in US 6 240 609 mentioned above, the specification of which patent is incorporated herein for all purposes by way of reference.

The invention will now be illustrated by way of non-limiting examples.

EXAMPLES 1 - 9

In a first group of examples, pseudo space-dyed yam was produced with pre- entangling before texturizing. In these examples, an apparatus of the type known as MICROFIL®, model 370-6D-24, produced and sold by Tecnofil (Cerro Maggiore - Italy) and generally structured as shown in Fig. 3 was used including 3+3 (i.e. tliree extruders for each half-machine) extruders of 60 mm diameter each, set up for production of 12+12 yams (i.e. 12 on each side) of three colors each.

Drawing was effected as specified below. Texturizing was effected with texturizers supplied by Tecnofil, model 751116C with 24 slots and operated at a pressure of 6 bar. Pre-interlacers (pre-entanglers), again supplied by Tecnofil, were used an operated at 6 bars. For interlacing of the combined strands, an Interlacer TEMCO® model LD32 was used and operated at 7 bars. Winding of the yam was effected with a 12+12 Winco model F3001 (manufactured and supplied by Balema, Switzerland) winder installation operated at a speed of at least about 2400 m/min.

Twelve yams, each consisting of tliree differently colored strands each were obtained on one side of the machine and another twelve yams on the left side. Strand colors on the right side of the MICROFIL® machine were as follows: yellow (Y); cyan (C) and magenta (M). Pseudo space-dyeing effects were obtained by controlling the fluid input into the entanglers as specified in US patent 6 240 604 cited above. Example 1

Spinning of commercial polyamide resin was effected at a temperature of 261°C at a speed of 625 m/min. The as-spun filaments were contacted with cold rolls (Fig.3 311; 312) of 180 mm diameter and drawn at a rate of 6,66 kg/hour at a speed of 2100 m/min. The trio-rolls (321; 320; 322) had diameters of 210 mm each and were operated at 70°C and a peripheral speed of about 500m/min. All rolls (323; 324; 325, 326 and 327) used for drawing are large cylinders of 500 mm diameter each. First and second drawing rolls (323; 324) are "slow" rolls, i.e. operated at a speed of 500 m/min and at temperatures of 90°C and 180°C, respectively. Each color is treated as an independent strand. Prior to texturizing as disclosed in US patents 3 433 008, 4 043 010, and 4 248 036, and after passing all "fast" drawing rolls (operated at peripheral speeds increasing from 1200 m/min through 1500 m/min to about 2100m/min) each strand was interlaced with an air-operated entangler at 220°C. The entangled strands were collected and combined in a common texturizer (36) at the same speed and at 220°C. After exiting from the texturizer, the yarn was cooled down on cooling roll (38). Yam tension was reduced for entangling the strands.

A yam of 1800 dtex (Standard measure for fiber thickness: 1 dtex = 1 g/10 km) was collected and interlaced at a speed of 1850 m/min by an entangler (35) operated as defined above and wound up at the same speed for a total production rate per yam of 19,98 kg/h.

Example 2

Operation of Example 1 was repeated except that tension on the strands was regulated between the last two drawing rolls (326 and 327) of the MICROFIL® by a controller in position (34a). Each strand was interlaced at 2100m/min by an air entangler as above and operated at 220°C.

Example 3 The operation of Example 1 was repeated except that texturizing (crimping) was effected mechanically as disclosed in US patent 2 865 080. Example 4

Example 1 was repeated except that tension on the strands was regulated between the last two drawing rolls (326 and 327) of the MICROFIL® by a controller in position (34a) each strand at 2100m/min was interlaced with an air entangler operated at 220°C with mechanical crimping as in Example 3.

Example 5

Operation was as in Example 1 except that the polymer used for spinning was polypropylene extruded at a temperature of 242°C at a rate of 725 m/min and drawn as disclosed above to produce polypropylene filament strands of different colors each at a rate of 6,66 kg/h and a speed of 2170m/min.

Trio rolls having a diameter each of 210 mm were operated while the slow- operating large diameter rolls (diameter 500 mm each) were operated at 90°C and 95°C, respectively. The fast large-diameter rolls (500 mm diameter each) were operated at 125°C. The pre-entangler was operated with hot air at 175°C, the texturizer at 172°C.

Example 6

Operation was as disclosed Example 2 except that the polymer was polypropylene with operating conditions as described in Example 5.

Example 7

Operation was as described in Example 3 except that the polymer spun was polypropylene while operating speeds and temperatures were as specified in Example 5.

Example 8

Operation was as described in Example 4 except that the polymer spun was polypropylene while speed and temperature conditions were as specified in Example 5.

Example 9 Strands with six different colors, i.e. yellow, cyan, and magenta produced on one side ("right") of the MICROFIL® machine and white (W), black (B) and green (G) on the other side ("left") were spun as described in the above examples. Two yarns of 1800 dtex emanating from two texturizers, one from right side of the Microfil with a combination Y - C - M of colors, and the other from left side with a combination of colors W - B — G were interlaced together at speed of 1850m/' by an entangler for producing a six-color yam of 3600 dtex at a total production capacity of 39,96 kg/h per each final yam.

EXAMPLES 10 - 12

The following examples illustrate operation according to the invention with pre- interlacing after the texturizing step. Polymers, apparatus and operating conditions were the same as in Examples 1 - 9 except that an entangler was arranged for each strand downstream of texturizer 36 and cooling roll 38, and upstream of the second entangler for intermingling the strands used for production of the final yarn.

Example 10

Strands of three different colors were spun to obtain three types of strands, each strand type having the same color. The strands were individually texturized (crimped) by impact of a fluid and pre-entangled separately after cooling. The pre-entangled strands were than combined and interlaced together for forming the final yam.

Example 11 Example 10 was repeated except the strands were crimped mechanically as disclosed in US patent 2 865 080.

Example 12

Operation was as described in Example 10 except that strands of six differing colors were produced from two different spinning groups. The strands were combined to form two types of different pseudo space-dyed yarns or one yarn combining all six colors.

Example 13 Samples of tufted carpets were made by a conventional weaving method from pseudo space-dyed yams produced according to examples 1 — 12 and compared with samples made from yams consisting of strands of the same differing colors but without the pseudo space-dyeing effect obtained according to the invention. The carpet samples made from pseudo space-dyed yarns according to the invention had a clearly superior appearance as regards general color appearance and vividness, and a significantly more evident coloring pattern for the carpets was obtained.

It is apparent from the above explanations that the invention provides yams for various kinds of textile structure with a loop pile of the type disclosed in US patents 4 020 774 and 4 404 999 incorporated herein by way of reference.

Normally, a generally suitable way to produce a good quality carpet and, at the same time, maintain high production capacities is to use high denier yam for obtaining a more attractive carpet appearance. It is desirable to give emphasis to the constituent colors, that is, to avoid uniform coloring at the surface. For that reason, various methods of yarn production are used. For example, two or more strands of different colors are mixed to form the yam. However, when using such yarns, the carpet face color is flat and the color appearance is the combination of the single color components.

Alternatively, two or more yams are mixed and coupled using special apparatus known as twisting (or cabling) machines. When a loop is formed during the tufting process with such a yam (or twisted yarns), one of the yams composing the twisted (or cabled) yarn becomes more visible in a random manner. When a yam is made according to the invention of two or more differently colored strands that are interlaced per se to form a kind of twisted precursor yarn or thread and combining such precursor yams by interlacing to form a type of coupled (or cabled) yarn, loops formed in the tufting process upon carpet manufacture from such a yam, or at least containing such a yam (normally the one with an interlacing knot acquires more rigidity), will be more evident in those loops where one color predominates.

It is apparent that the improved appearance of carpets made from pseudo space- dyed yams according to the invention can be obtained in a most economic way, e.g. by retrofitting existing machines of the large and wide roll type discussed above. It is a particular advantage of the large and wide roll type machines modified according to the invention by pre-entangling of differently colored yam strands and post-entangling of the yarn-forming strands over the art (e.g. 4 025 595, 6 240 604, 6 094 790) that prior art processes are normally carried out by coupling of drawing rolls where the yam is wound up in more loops. Interlacing, according to this prior art, is allowed only between the last couple of draw roll with subsequent texturizing. In contrast, with a large and wide roll machine modified according to the invention it is possible to decide the position where pre-interlacing is effected in the yarn forming process.

In order to increase the vividness of the colors or the color appearance and randomness it is possible according to the invention to obtain as many color combinations as is permitted by the basic colors of the strands. For example, using three strands of different colors, say the above (Y) yellow,

(C) cyan, and (M) magenta, it is possible to obtain up to seven different color combinations ("+" indicating a color combination):

Y = solid yellow C = solid cyan M = solid magenta

Y + C = mixed green A + M = mixed orange C + M = mixed purple

Y + C + M = dark brown

According to the invention disclosed herein it is possible to obtain evidence of a single strand or thread. The invention permits both randomly distributed effects as well as production of predetermined patterns by simple switching from one basic color to another one. To this end, color distribution in a yam can be controled by controlling pre-interlacing in a random or pre-calculated manner by using On Off-switches for the actuator of the pre-interlacer. For example, the pre-interlacer may be controlled to produce about 35 knots per meter of strand, and the post-interlacer may also produce about 35 knots per meter of yam.

In this context, a "knot" is a portion of the strand (or yam) where the filaments loose their normal parallel reciprocal position and are deviated to form a kind of plait section: such crossing is generally said to be a "knot". A knot is a portion of a strand which is difficult for another strand to penetrate, both within the interlacer or outside thereof. As a consequence, a knot forms an "impenetrable" section of a strand, and two or more strands remain un-intermingled in the portions where they have knots.

In the absence of knots, filaments remain parallel and more amenable to intermingling during the final interlacing of the sfrands when forming the yarn. Such a system can be achieved by means of timed On/Off pre-interlacing with a random actuation of the pre-interlacing device to obtain all possible color combinations as explained above.

With such random arrangement of color combinations it is possible to have nuances over a loop pile which emphasize up to as many different colors as can be combined.

It will be apparent to those experienced in the art that the above examples are given for the purpose of illustration and not of limitation, and various modifications will be apparent to those experienced in the art within the scope of the subsequent claims.

Claims

1. An apparatus for producing a pseudo space-dyed yarn formed of at least two strands of filaments, said at least two sfrands having differing visual appearances, said apparatus comprising

(A) a filament-forming means for producing said sfrands of said filaments by melt spinning and stretching them in an integral process;

(B) a first entangling means for separately entangling each of said at least two strands while still at an elevated temperature by a laterally impacting fluid having an elevated temperature;

(C) a texturizing means for texturizing each of said at least two strands at an elevated temperature;

(D) a cooling means for cooling said at least two strands to an ambient temperature;

(E) a second entangling means for commonly entangling said at least two strands by a laterally impacting fluid having ambient temperature to obtain said pseudo space-dyed yam; and

(F) a winding means for collecting said pseudo space-dyed yam obtained from said second entangling means.

2. The apparatus of claim 1 wherein said filament-forming means (A) includes:

(Al) means for simultaneously extruding a sufficient number of filaments for forming said at least two strands into an essentially vertical air quenching zone for solidification of said filaments;

(A2) means for arranging said filaments strands so as to form a substantially planar array of said at least two strands in a parallel arrangement;

(A3) means for together pre-stretching said filaments strands by passing ι said yam strands, while maintaining them in said array, in frictional contact with peripheral surface portions of at least two rotating draw cylinders, each strand passing over said surface portions along a discrete path which is substantially defined by a plane intersecting perpendicularly with said parallel axes of rotation of said at least two rotating draw cylinders; each of said rotating draw cylinders having a diameter sufficient for providing a contact path length for said filaments of from about 1 meter to about 6 meters; and

(A4) means for passing said at least two sfrands while maintaining them in said array, in contact with peripheral surface portions of at least two additional rotating draw cylinders having axes of rotation parallel to said first and said second rotating draw cylinders for additionally stretching said filaments, each said strand passing over said surface portions along a discrete path which is substantially defined by a plane intersecting perpendicularly with said parallel axis of rotation of said at least two additional rotating draw cylinders, said additional rotating draw cylinders each having a diameter greater than about 300 mm.

3. The apparatus of claim 1 or 2 wherein said winding means (F) is capable of operating at a speed of at least about 1000 meters per minute.

4. The apparatus of claim 2 or 3 wherein said extrusion means (Al) are capable of extruding said filaments at a speed of at least 400 meters per minute.

5. An apparatus for producing a pseudo space-dyed yam formed of at least two strands of filaments, said at least two strands having differing visual appearances, said apparatus comprising

(a) a filament strand forming means for producing said filaments sfrands by melt spinning and stretching them in an integral process comprising: (al) means for simultaneously extruding a sufficient number of said filaments for forming said at least two filament strands into an essentially vertical air quenching zone for solidification of said filaments;

(a2) means for arranging said filaments strands so as to form a substantially planar array of said at least two sfrands in a parallel arrangement; (a3) means for together pre-stretching said filaments strands by passing said strands, while maintaining them in said array, in frictional contact with peripheral surface portions of at least two rotating draw cylinders, each sfrand passing over said surface portions along a discrete path which is substantially defined by a plane intersecting perpendicularly with said parallel axes of rotation of said at least two rotating draw cylinders; and

(a4) means for passing said at least two sfrands while maintaining them in said array, in contact with peripheral surface portions of at least two additional rotating draw cylinders having axes of rotation parallel to said first and said second rotating draw cylinders for additionally stretching said filaments, each said strand passing over said surface portions along a discrete path which is substantially defined by a plane intersecting perpendicularly with said parallel axis of rotation of said at least two additional rotating draw cylinders; (b) a texturizing means for texturizing said at least two sfrands at an elevated temperature;

(c) a cooling means for cooling said at least two strands to an ambient temperature;

(d) a first entangling means for separately entangling each of said at least two strands by a laterally impacting fluid;

(e) a second entangling means for commonly entangling said at least two strands by a laterally impacting fluid to obtain said pseudo space-dyed yarn; and

(f) a means for collecting said pseudo space-dyed yam obtained from said second entangling means.

6. A method of producing a pseudo space-dyed yarn formed of at least two strands of filaments, said at least two strands having differing visual appearances, said method comprising the steps of:

(A) producing said filament sfrands by melt spinning and stretching them in an integral process;

(B) separately entangling each of said at least two sfrands while still at an elevated temperature by a laterally impacting fluid having an elevated temperature;

(C) texturizing each of said at least two strands at an elevated temperature;

(D) cooling said at least two strands to an ambient temperature; (E) commonly entangling said at least two strands by a laterally impacting fluid having ambient temperature to obtain said pseudo space-dyed yam; and

(F) collecting said pseudo space-dyed yam obtained from said second entangling step.

7. A method for producing a pseudo space-dyed yam formed of at least two sfrands of filaments, said at least two sfrands having differing visual appearances, said apparatus comprising the steps of: (a) producing said filaments strands by melt spinning and stretching them in an integral process by:

(al) simultaneously extruding a sufficient number of said filaments into an essentially vertical air quenching zone for solidification of said filaments; (a2) arranging said filaments so as to form a substantially planar array of said at least two strands in a parallel arrangement;

(a3) together pre-stretching said filaments by passing said yam sfrands, while maintaining them in said array, in frictional contact with peripheral surface portions of at least two rotating draw cylinders, each strand passing over said surface portions along a discrete path which is substantially defined by a plane intersecting perpendicularly with said parallel axes of rotation of said at least two rotating draw cylinders; and

(a4) passing said at least two strands while maintaining them in said array, in contact with peripheral surface portions of at least two additional rotating draw cylinders having axes of rotation parallel to said first and said second rotating draw cylinders for additionally stretching said filaments, each said strand passing over said surface portions along a discrete path which is substantially defined by a plane intersecting perpendicularly with said parallel axis of rotation of said at least two additional rotating draw cylinders; (b) texturizing each of said at least two strands at an elevated temperature; (c) cooling said at least two strands to an ambient temperature;

(d) separately entangling each of said at least two sfrands in a first entangling step by a laterally impacting fluid;

(e) commonly entangling said at least two strands in a second entangling step by a laterally impacting fluid to obtain said pseudo space-dyed yam; and (f) collecting said pseudo space-dyed yam obtained from said second entangling means.

8. The method of any of claims 6 - 7 wherein the entangling operation in said second entangling step is interrupted periodically or aperiodically for producing a yarn with periodically or aperiodically alternating entangled and un-entangled sections.

9. A pseudo space-dyed yam obtained by the method of claim 8, wherein, said periodically or aperiodically alternating sections having a length of between about 2 and about 20 mm.

10. A carpet made of a pseudo space-dyed yarn according to claim 9.