IL32557A - Method and apparatus for ringless spinning of composite fiber-polymer yarns - Google Patents

Description

METHOD AND APPARATUS FOR RINGLESS SPINNING OF COMPOSITE FIBER-POLYMER YARNS D'nian D'Din ^ff fcV? Γ ΙίΛ I mi Πϋ">Ε7 This invention relates to a novel method and apparatus for continuous l inear production ofj composite staple fiber-thermoplastic polymer spun yarns.

More particularly the invention relates to a I fundamentally novel concept of spinning yarns consisting of staple fiber-thermoplastic polymer blends or combinations, whereby the twist is imparted to said yarns and substantially retained j ; therein between two fixed pinch poi;nts in a continuous l inear sequence of operations.

Ever since staple fiber spinning began, there has prevailed a recognized yet unchal lenged fundamental principle that in order to impart and retain a twist in a strand comprising staple fibers, by any means, one end of the strand must be free to rotate.

Accordingly, if any attempt is made to impart twist to a continuous strand of staple fiberjs, which is held at both ends, right hand twist will appear on the strand at one side of the twisting device and will be offset by left hand twist at the other side of said device. The net result will be yarn with zero twist, because the left and right hand twists null ify each other. This is commonly known as false twisting. j Consequently, all hitherto known methods of !staple fiber spinning fal l into three basic groups: 1. Rotating the yarn collecting package 2. Rotating the fiber supply package. 3. Rotating the end of the yarn to which a discontinuous loose stock is continually suppl ied.

Ring spinning, now predominantly used, belongs to the first category, which also includes the flyer, cap and pot spinning The second, rather uneconomical method, finds l ittle practical appl ication in the yarn spinning art. to any composite staple f i ber -thermopi ast i c polymer material, whereby contrary to the above mentioned fundamental concept, I twist will be imparted and retained in the yarn between two fixed pinch points, such as l inear feed-in rolls and 1 inear col lect ion rol 1 s . I It is therefore a principal object of the present invention to provide a novel method and apparatus which will make it possible to impart to a composite staple fiber-thermoplastic polymer strand, web, tape or the l ike material, a predetermined twist and to retain a substantial portion of said twist without the necessity of either revolving the feed-in end or the collecting package and without the need to create a discontinuity in the iber mass at the feed-in end, as is the case with all open end spinning methods.

A further object of the invention is to provide a method and an apparatus which will enable manufacture of staple fiber-thermoplastic polymer yarns by means of a totally l inear operation i and at substantially higher production speeds than those of the presently known systems.

A still further object of the invention is to provide a relatively simple method and apparatus which will adequately exploit the technological advantagejs of appl icants' novel principle and achieve at high speeds and in a continuous sequence of operations l inearly wound packages of spun staple fiber-thermo-plastic polymer yarns ready for utij1 i zat i on .

! I Other objects and advantages of the invention will be apparent from the following more detailed description.; The technological feasibil ity and important economical advantages of the present invention are based on the possibil ity to retain, to a substantial degree,! the twist imparted to a consol idated, composite, continuous' staple f iber -therrriopl ast i c polymer stock-in material (tape, strand or the l ike) between two fixed pinch points, for example the stock-in material isupply rolls and the l inear yarn collecting rolls, by providing between said pinch points a suitable heating zone through which the composite tape, strand or the l ike material passes and wherein it is heated to a point where the thremopl ast i c polymer substrate of the composite material becomes plastic without reaching the melting poin of said polymer. The composite material is then twisted in said zone while the polymer substrate is in such plastic condition to achieve i nter s 1 i page of the polymer molecules and hel ical rearrangement of the fibers, and finally it is cooled to coagulate the polymer while the material is in such twisted condition, thus substantially retaining the achieved twist.

The basic method according to the present invention will therefore comprise the following steps: (a) l inearly supplying through feed-in rolls a continuous strand or tape of substantially consol idated staple fiber-thermoplastic polymer composite material ; (b) heating said strand or tape to a point where the polymer substrate of the composite material becomes plastic without reaching the melting point of said polymer; (c) subjecting said heated strand or tape to a torque within a fiber-restrictive zone for impart ing a predetermined! twist to said strand or tape through intermo l'ecular sl ippage of the polymer molecules as wel l as interfjiber sl ippage and consequent hel ical rearrangement of the fibers'; j ! (d) cool ing to coagulate the polymer substrate while the strand or tape is in such twisted condition to substantially retain the twist; and ' (e) l inearly winding up the obtained spun yarn on a collecting roll . : Consequently, the basic apparatus according to the invention will comprise the fol lowing combination: j (a) feed-in rolls for l inearly supplying a continuous fibrous strand or tape of substantially consol idated staple fiber-thermoplastic polymer material ; (b) a heater with proper temperature control means and a fiber-restrictive zone, through which said fibrous strand or tape is adapted to pass and in which it is heated until the polymer substrate becomes plastic without reaching the melting point of said polymer; (c) a torque imparting device following said heater for twisting said strand or tape while the polymer is in plastic condition to enable i ntermol ecu 1 ar sl ippage of the polymer molecules and accompanying hel ical rearrangement of the fibers bonded to said polymer due to interfiber sl ippage caused by friction within the fiber-restrictive zone; with only one strand or tape at a time. This is usually done by j extrusion of a plural ity of parallel thermoplastic resin strands from an extrusion die and lamination as well as consol idation thereof with suitable webs of staple fibers arranged at random or in parallel . The extruded thermoplastic strands can also be stretched to achieve an initial degree of molecular orientation of the polymer.

The heating of the composite fibrous strands or tapes to the point of rendering the polymer substrate plastic but without reaching the melting point of said polymer substrate can be effectively accompl ished by passing said composite strands or tapes in a heater provided with longitudinal grooves generally in the form of V.

The composite fibrous strands or tapes are progressively heated while passing in these grooves to the point where the polymer substrate present therein acquires the desired plasticity. The V shaped grooves can also be gradually narrowing towards the exit end of the heater so that the composite strands or tapes, passing therein, are simultaneously compressed, thus achieving a better interaction and consol idat ion between the polymer and staple f ibers, and ensuring the hel ical rearrangement of the loose staple ends during the twist iimparting operation1.

The heater should also be provided with adequate temperature control means because it is essential to adjust the temperature to the point where, as mentioned above, the polymer substrate will attain the desired degree of pi ast i c i t w i thout reaching however the melting temperature of said polymer.

This point of plasticity yaries from polymer^ to polymer but it can be easily ascertained byj a man famil iar with the art.

Also, the melting points of most thermoplastic polymers are readily available from the l iterature. The reason, of course, why the polymer must have a degree of plasticity is to achieve inter-sl ippage of the polymer molecules and inter-fiber sl ippage of the staple fibers embedded in the polymer substrate when torque is imparted to the fibrous composite tapes, thus enabl ing' hel ical rearrangement and cohesion of the staple fibers, with the polymer in plastic state playing essentially the role of a binder and a lubricant; and the reason why it should not exceed the melting point is because at this point the strand or tape wil l lose its continuity (since the polymer wil l become l iquid) and also the material will become very tacky and will stick to the surface of the heater thus preventing proper function of the operation and the achievement of the desired result.

The torque is imparted to the composite f ibrous strand or tape below the above mentioned heating zone and the created twist travels upwards to the point lof greatest plasticity of the polymer where it is melted-in thus jprevent i ng formation of a counter torque which would tend to ;null ify the imparted twist.

It can, for example, be imparted by means of any false twisting device which may revolve at speeds |of up to 500*000 r.p.m.

It should also be noted that even though the polymer y imparting torque due to its consequent circular polymer stretching act ion .

The novel universal apparatus of the present invention may therefore comprise in a preferred embodiment the following I combination: j an extruder and an extruder die from which a curtain of thermoplastic polymer strands or strips of a desired configuration can be extruded; a pair of c i rcumferent i al 1 y grooved consol idating rolls below said extruder die, said rolls being positioned side by side and so that the male members or protrusions of the grooved surface of one roll enter and press into female members or grooves of the other roll; the polymer extrudates being directed into the nip of said rolls so that at least one extrudate strand or strip enters into each consol idating groove; means for simultaneously jforwarding from at least one side of said polymer curtain and into the nip of said rolls a plurality of staple fiber webs, one; into each consol idating groove of the rol 1 s ; means for pressing said rolls against each other; means for rotating said rjolls toward each other at a speed higher than the extrusion spe'ed of the polymer curtain; means for cool ing said rolls or the material passing I therethrough; ; ■ j thus the product i ssu i ng ifrom these rolls, which constitute the first fixed pinch pojint, consists of consolidated and partly oriented composite staplje fiber-thermoplastic polymer i fibrous strands or tapes; j then, following the consol idating rolls, there is provided a preferably V grooved heater having as many grooves of gradually narrowing V cross-section as there are composite strands or tapes coming out of the consolidating rolls so that each strand or tape can enter one groove of the heater; the V grooves preferably gradually narrow towards the exit end in order to produce a further compaction and improved co-action between thejstaple fibers and the polymer material as well as to ensure the hel ical rearrangement of the loose ends of the staple fibers during twisting means for adjusting and controlling the temperature of said heater; a plurality of torque imparting devices, e.g. of the false twisting type, following said heater, one for each strand or tape, for imparting to the latter a predetermined twist inside the grooves of the heater; means for cooling the twisted composite strands or tapes provided between the heater and the torque imparting devices; a pair of pick-up rolls following the torque imparting i devices constituting the second fixed pinch point and adapted to i l inearly collect and hold under tension the final twisted yarns coming out of the twist imparting devices; and i one or more collecting rolls following these pick-up I rolls for l inearly winding-up the obtained twisted yarn.: There are also many further preferential features of the j present invention which will be discussed in greater detail in the following non-l imitative embodiments given with reference to the appended drawings in which: | Figure 1 is a generally schematic view of the basic method j ' and apparatus of the present inventjion; Figure 2 is another generally schematic view1 of a device which may be used in combination with the apparatus of Figure 1; Figure 3 is a view of c i rcumferent ial 1 y grooved rolls in ί engaged condition, along l ine A-A of Figure 2; Figure 4 is a schematic illustration of one preferred complete operation according to the present invention;! Figure 5 is a side view of a complete universal apparatus according to the present invention; and Figure 6 is a view, partly in section, along l ine B-B of Figure 5·.

The basic principle of the invention is illustrated in Figure 1. A composite fibrous staple fiber-thermoplastic polymer tape 10 is suppl ied to the pinch point of a pair of pick-up rolls 11, 12 which constitute the first fixed point within the scope of the invention. Then, said tape 10 is l inearly fed by these rol ls 11, 12 to the grooved heater 13 with heating means 14 which operate so as to enable adequate temperature control in the heater 13.

It should be pointed out that the shape of the heater is preferential and by no means l imitative and any heater with a exit from the heater, however, one may also include suitable cool ing means for that purpose, such as a water coo 1 ed! j acket and/ or a compressed air cool ing zone. j During the twisting operation, the twist, therefore, travels upwards from twister 16 to the heater 13 where! it is melted-in into the continuous composite strand or tape1 having its polymer substrate in plastic condition.

After passing through twister 16, the yarn is picked up by a pair of pressure rolls 1 7 , 18 which constitute the second fixed point according to the invention, and thereafter it is linearly wound on a collecting roll 19 to form the final spun yarn package 20 . It is possible to el iminate rolls )J, 18 entirely since the collecting roll 19 Itself may constitute the second fixed point, however, said rolls 17 , 18 are preferred to keep the yarn under proper tension.

Figure 2 shows an arrangement for direct production of composite tape 10 which can be used in combination with that of Figure 1. According to this arrangement, tape 10 can be produced ! by direct extrusion of a thermop 1 asjt i c polymer strand or extrudate 23 from extruder die 22 of extruder! 21 and its lamination and consol idation with a web of staple fibers 24 between rol ls 11a and 12a. The web of staple ibers 24 may be suppl ied from one or both sides of extrudate 23 towards jthe nip point of the laminating and consol idating rol ls 11a, 12a, simultaneously with said extrudate I 21 which is sti l l in tacky condition after its extrusion from die 22. Said web is then laminated and consol idated with said extrudate by pressure and cool ing, i .e. by the act ion of said rol ls 11a, 12a ! i which may be internal ly cooled by cool ing water or air. The employed staple f iber webs may easijly be produced by means of a drafting frame 25 such as used in the drawing of sl ivers or rovings or by aerodynamic systems which are wel l known in the art.

The rol ls 11a and 12a in this instance serve the same purpose as rol ls 11 , 12 in Figure 1 , namely for supplying j composite tape 10 to the heater 13· Thus, in combination comprising the arrangement of Figure 2 together with that of Figure 1 , rol ls 11 , 12 of Figure 1 would be replaced by rol ls 11a, 12a of F igure 2.

Furthermore, it would be rather uneconomical to operate according to this invention with only one composite tape 10.

Thus, rol ls 11a, 12a preferably have the form shown in Figure 3· In the case il lustrated in Figure 3> six tapes at a time can be processed. This, of course, would require extrusion of a curtain of six strands 23 from die 22 and their simultaneous consol idation and lamination within the grooves 27 with six webs 24 to form six composite tapes at a t ime. The form of the rol ls i l lustrated in Figure 3 is particularly effect ive since it wi l l directly produce the required composite tapes due to j pressure exerted by protruding members 28 of rolls 12a within circumferential grooves 27 of rolls i 11a and any material that may overfjlow or sl ip into the pointed grooves 29 of rol l 12a wil l be cut by cutting edges of protruding members 26 of rol l 11a, or it wil l be kept separated from its j adjacent material stream by the protruding members 26 of rol l 11a.

However, this particular form is in no way l imitative and any rol ls or drums that wil l produce the same function are acceptable (e.g. all the circumferential grooves of jthe consol idating rol ls may be of square cross section); also, jthe number of groov s within which the composite tapes are produced is not l imitative.

In case a pair of rol ls lila, 12a, such as shown in Figure 3> are used, the heater 13 w!i 11 be modif ied to have the j ί number of V grooves that will correspond to the number of composite tapes suppl ied by said ro!lls, in this particular example, six. Also, six twisting devices 16 will be required, one for each tape. Six col lecting rolls 19 may also be used to form six packages 20 of spun yarn. ! i Furthermore, consol idating rolls 11a, 12a ca!n be driven at a substantially higher speed (e.g. 10 times higher) than the extrusion rate of the polymer strand 23, thus producing stretching and, consequently, a good degree of molecular orientation of said polymer strand. This, together with the additional effects of hel ical fiber rearrangement as wel l as further stretching due to twisting, wil l enable achievement of a product of excel lent strength and stabil ity.

Another way of carrying out the method of the present invention, while achieving ultimate strength in the f inal yarn, is illustrated in Figure 4. According to this embodiment, polymer strand 23 (or a plural ity of such strands) is extruded from extruder 21 through die 22 and is thereafter stretched and oriented to a very high degree by means of orienting arrangement ί . This arrangement is known in t:he art and usually consists I of a pair of sets of godet rol ls (each set having three rolls with each set running at a higher speed than the preceding set) interposed with a heater with proper temperature control . Strand 23 is thus first stretched to a desired degree by the first set I of godet rolls then heated and finally stretched again by the second set of godet rolls. Such treatment gives a very high degree of molecular orientation to jthe strand 23· Thereafter, the oriented strand is passed through a heater arrangement 31 > which preferably consists of a tunnel heater with adequate I I temperature control . Here, the strjand 23 is heated only to such a degree that it will become tacky on the surface at the e it end of the heater without losing its previously acquired internal i molecular orientation. It should bje noted here that it is certainly possible to impart to a thermoplastic extrudate, through such operation, a desired degree of tackiness without impairing the molecular orientation of the polymer. Indeed, complete relaxation will only occur in the thermoplastic material when the latter is held at or about its melt temperature for a period of time. The time will depend on the degree of orientation, thickness of material and the surface area of contact.' For example, in the case of polypropylene no shrinkage due to relaxation will occur when the extrudate is held at 40° C for thirty minutes, although some shrinkage will occur if it is held at that temperature for forty-five minutes. Also, if an extrudate of pol propylene is heated in air for thirty minutes at 100° C, less than five per cent shrinkage will occur while a further thirty minutes heating at 1 5° C will produce an additional seven per cent shrinkage. It is therefore quite evident that when, in our case, the oriented strand 23 passes through the heating arrangement 31 J the latter may easily be adjusted so that some degree of surface tackiness will be! imparted to the strand with very l ittle if any loss in its molecular orientation. This is especially true since the strand 23; will travel at a speed of perhaps one thousand feet per minute or so and its residence time in the heating arrangement 3 1 will !be insufficient to obtain j . relaxation of the polymer even if high temperatures prevail in said heater, although it will be sufficient for imparting to said polymer strand a desired degree of jtack i ness . : j I The tackiness of strand 23 is, of course, necessary in order that it may be laminated and jconsol i dated by rolls 1 1 a , 1 2a with the web of staple fibers 24 to form a composite tape 1 0 . The staple fiber web 24 is suppl ied by supply arrangement 25 to the nip of rolls 1 1 a , 12a and actually two such webs can be suppl ied for each strand, one from each side, so that the final composite tape 1 0 would consist of^ polymer substrate fully surrounded with staple fibers having numerous loose ends sticking out and providing the desired fibrous surface texture!. 1 i This composite tape 1 0 is then processed as' in the previous cases through heater 1 3 which preferably has its heating surface in the form of a gradually narrowing V groove toward exit end 1 5 , so that further compaction between the polymer substrate and the surrounding staple fibers can be achieved as they pass through said heater. At a predetermined point inside the heater 1 3 > the polymer substrate of the composite tape 10 is sufficiently plastic that the twist imparted by twister 16 and travell ing upwards will produce i nters 1 i ppage of the polymer molecules and of the staple fibers bonded to the polymer substrate well as coagulation of the yarn in such hel ically twisted condition due to subsequent cool ing. Thereafter the twisted yarn passes linearly through the twister 16 and tension rolls 1 7 > 18 and is l inearly wound, at speeds up to andj in some cases in excess of I one thousand feet per minute, on the collecting roil 1 to form the final spun yarn package 20 . j i Figure 5 illustrates one possible construction of a universal yet relatively simple and compact apparatus embodying the necessary features of the present invention while Figure 6 shows a detail thereof along line B-B .

In the apparatus illustrated in these figures, a curtain j of strands 23 is extruded through the extrusion die 22 of extruder 21 which is hel d by member 32 mounted on a he i ght adj us i ng i I column 33 · In this manner, the pos!ition of the die 22! over the consol idating rolls 1 1 a , 12a can be; easily controlled.; The extruder is also provided with hopper 34 into which the thermoplastic material can be introduced J i n its cheapest form, namely in the form of lumps or granules, j The continuously extruded strands 23 may be of any desired cross-section; the simplest cross-section, i.e. the round one, is actually the preferred. j The laminating and consolidating rolls 1 1 a , 1 2a are provided on their surface with a plurality of circumferential grooves and one or more strands 23 are introduced into each groove of said rolls, directly upon extrusion and while still i n tacky condition, for compression and consolidation with staple fiber webs 24 which are also conveyed into said grooves from one or both sides by fiber web supply means 25 shown, in this case, schematically and in broken line as two superimposed rollers.

These means may, for example, be a drawing frame or any other device capable of producing a plural ity of webs consisting of parallel or at random arranged staple fibers.

The rolls 1 1 a , 1 2a may be driven at substantially higher speed than the extrusion rate of strands 23 * thus producing another. Other means for pressing one roll against the other and disengaging the same, if need be, can also be used and the mechanism shown in Figures 5 and 6 has been given for illustration purposes only without any restriction whatsoever.

The apparatus is then provided with heater 1 3 which is suitably mounted within the frame 35 · The heating surface of this heater has a plurality of gradually narrowing V grooves so that when the composite tapes 10, after consol idation and lamination by rolls 1 1 a , 1 2a , are guided within said grooves, they are not only heated to the desired temperature but also the staple fibers are further compacted and helically rearranged with the polymer material. Within the grooves of the heater 1 3 / the polymer material reaches such plastic condition that a twisting torque imparted from below by twister 16 will be melted- in and retained therein due to i nters 1 i ppage of the polymer molecules and of the staple fibers. The staple fibers will be hel ically rearranged and better amalgamated with the polymer due to the prevailing conditions of twisting and polymer plasticity, thus resulting in util ization of the stable fiber strength in twisted structure form towards the total yarn strength. Efficiency of fiber strength to yarn strength conversion, generally no more than 50$ in conventional staple fiber spun yarns, is considerably increased by the binding according t!o this invention of the staple fibers to a thermoplastic polymer substrate thus arresting their ! i slippage in the axial direction in the final composite yarn. For instance, a fibrous tape which has a tenacity of about) g./tex. can by applicants' new method be converted into a yarn of about 1 2 g./tex. tenacity.

Upon its exit from heater 1 3 j in twisted condition, the composite material will be cooled in an air feeding and cool ing injector 36 whereby the twist in the polymer becomes permanently coagulated. Twisted yarn 40 is thus obtained and after passing through the torque imparting device! 16 end tensioning rolls 1 7 * 18, as well as a conventional guiding arrangement 41, it is linearly wound on collecting roll 1 9 at speeds that may reach and even exceed one thousand feet per minute, to form the final spun yarn package 20 . The twist is therefore imparted according to the present invention and according to the embodiment illustrated in these figures between two fixed pinch points, in this case between rolls 1 1 a , 1 2a and rolls ] , 18, in a totally continuous linear operation with quality spun yarn being produced at considerably higher speeds than those of hitherto known systems.

The apparatus is relatively simple in nature and very easy to operate. Thus, the thermoplastic polymer, for example of the group of polyamides, polyolefins, acryl ics and the l ike, can be introduced into the hopper 3 in granular form and extruded at a rate of about one hundred feet per minute through extruder die 22 in the form of a curtain of strands 23 of round or any other preferred cross-section.

The strands are extruded toward the nip of circumfer-entially grooved laminating and consolidating rolls 1 1 a , 1 2a which can be driven at a speed of about one thousand feet per minute, thus with a ratio of about 1 0 to 1 relative to the speed of extrusion. A substantial molecular orientation of strands 22 will thus be achieved.

By the action of said rol s 1 1 a , 1 2a , the strands are consol idated with webs of staple fibers 24 which are simultaneously supplied by device 25 into the grooves of said rolls, thus achieving formation of composite tapes 10 having, for example, aj fiber-polymer ratio of 50 : 50 . Other ratios of f iber-pol ymer| can, of course, also be used. The composite tapes are then guided through heater 13 provided with fiber-restrictive grooves or zones and an adequately controlled temperature and wherein the polymer substrate of said tapes reaches a plastic, lubricating condition which makes it possible to impart, to said tapes, from below, a predetermined twist by twister 16 which may run at speeds of up to 500 ,000 r.p.m. Then, the twisted yarn, coming out of the heater, is cooled to coagulate and permanently retain to a substantial degree the imparted twist. Thereafter, upon linearly passing through a pair of tensioning rolls 1 7 , 18, which may be driven at a higher speed than that of rolls 1 1 a , 1 2a so as to effect further stretching and orientation of the polymer (thus achieving even further increase in the strength of the final yarn), the obtained spun yarn is continuously and linearly wound on collecting roll 19 to form a commercially acceptable spun yarn package 20 .

It should, of course, be understood that many modifications in the process and apparatus of the present invention are possible and would be evident to those familiar with the art. For example, the apparatus illustrated in Fig. 5 could, if desired, be combined with the arrangement shown in Figure 4 or any other similar arrangement without, in any way, a fect ing the basic concept of this invention. Thus, although the optimum production output of a 16 twist per inch staple fiber yarn, for ring spindles, i is known to be about 70 - 100 feet per minute and in open-end i spinning about 100 - 200 feet per minute, appl icants' ringless continuous yarn production enables output speeds of 500 - 1000 ϊ i and, in some cases, exceeding 1000 feet per minute, whrich is i unattainable by any hitherto known yarn making methods. i I j

Claims (14)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. Method of making fibrous spun yarns of composite staple f i ber- thermop 1 ast i c polymer material comprising: linearly supplying through feed-in rolls a continuous strand or tape of substantially consolidated composite fibrous material consisting of staple fibers and a thermoplastic polymer substrate; heating said strand or tape within a fiber restrictive zone to'a point where the polymer substrate of said composite material [becomes i plastic without reaching the melting point of said polymer; I ί subjecting said strand or tape within said fiber restrictive zone to a twisting torque for imparting thereto, while the polymer substrate is in plastic condition, a predetermined twist with consequent helical rearrangement of the fibers; cooling to coagulate the polymer while the strand or tape is in twisted condition; and linearly winding-up the obtained consolidated spun yarn on a collecting roll; said feed-in rolls and sa i d col lect i ng roll constituting two fixed pinch points between which the twist is applied and substantially retained.

2. Method of producing composite staple fiber-thermoplastic polymer spun yarn in a continuous linear sequence of operations comprising: extruding a curtain of thermoplastic polymer strands downwardly from an extruder die and toward the nip of a pair of ci rcumferent i al 1 y grooved consolidating rolls positioned side by side so that male members of the grooved surface of one roll enter and press into female members of the other roll, said curtain being directed so that at least one strand enters into each consolidating groove of said rolls; rotating said rolls at a greater speed than the rate of extrusion of the polymer strands so as to stretch the latter and achieve molecular orientation of the extruded polymer strands; simultaneously forwarding from at least one side of the polymer curtain and into the nip of said i rolls a plural ity of staple f iber webs, one into each consol idating groove of the rolls; laminating and j consol idat i ng said strands with said webs by pressure within the grooves of said rol ls and cool ing to form a plural ity of laminated staple fiber-thermoplastic polymer composite fibrous tapes; passing each of said composite fibrous tapes through a fiber restrictive heating zone and i subjecting it therein to a thermal treatment which will render the polymer plastic without reaching the melting po i nt. thereof ; imparting within said fiber restrictive heating zone tb the tape I with the polymer in such plastic condition a predeterm,i ned twist with consequent hel ical rearrangement of the fibers on; said tape; cool ing to coagulate the polymer while the tape is in such twisted condition; and l inearly and continuously winding-up the obtained I twisted yarn on a collecting roll , j

3. Method of producing composite staple fiber-thermoplastic polymer spun yarn in a continuous l inear sequence of operations comprising: extruding a curtain of thermoplastic polymer j strands; stretching said strands to achieve a predetermined orientation of the polymer molecules; passing the so oriented strands in a heater in which the temperature is so adjusted and controlled as to render the strands tacky on the surface while substantially retaining their previously acquired molecular orientation; introducing the tacky strands into the nip of a pair of c i rcumferent i al 1 y grooved consol idating rolls positioned side by side so that the male members of the grooved surface of one roll enter and press into female members of the other roll , said strands being directed so that at least one strand enters into each consol idating groove of said rolls; simultaneously forwarding from at least one side of the polymer curtain and into the nip of said rolls a plural ity of staple fiber webs, one into each consol idating I ! groove of the rolls; laminating and consol idating said strands with said webs by pressure within the grooves of said rolls and i cool ing to form a plural ity of laminated staple fiber-thermoplastic polymer composite fibrous tapes; passing each of said composite fibrous tapes through a fiber restrictive heating zone and heating it therein to a point where the pol ymer becomes pi ast i c w i hout reaching the melting point of said polymer; imparting within said fiber restrictive heating zone to the tapes with1 the polymer in such plastic condition a predetermined twist with consequent hel ical rearrangement of the fibers on said tape; cool ing to coagulate the polymer while the tape is in such twisted condition; and l inearly wir|iding-up the obtained spun yarn on a collecting roll. j i

4.. Method according to claims 1, 2 or 3, in which the obtained spun yarn is l inearly wound on the collecting roll at i speeds in the order of 500 - 1000 feet per minute.

5. Apparatus for producing composite staple fiber-thermoplastic polymer spun yarn comprising: ί (a) feed-in rolls for l inearly supplying at least one i continuous strand or tape of substantially consol idated staple fiber-thermoplastic polymer composite fibrous material; (b) a heater with temperature control means and a fiber restrictive zone through which said strand or tape is adapted to pass and in which it can be heated until the polymer becomes plastic without reaching the melting point of said pol ymer ; (c) a torque imparting device following said heater for twisting said strand or tape within said fiber-restrictive zone while the polymer Is in plastic condition; (d) means for cool ing said strand or tape in twisted condition, provided between the heater and the twisting device; and (e) a collecting roll andj means for l inearly winding-up the obtained spun yarn thereon. j

6. Apparatus according to claim 5> further comprising j means for forming a plural ity of said continuous strands or tapes of substantially consol idated staple iber-thermoplastic polymer composite material .

7. · Apparatus according to claim 6, in which said means I for forming a plural ity of said continuous composite strands or tapes comprise: an extruder with an extruder die having a plural ity of orifices al ined in a substantially straight l ine and i j adapted to extrude a curtain of polymer strands; a pair of c i rcumferent i a 11 y grooved consol idating rolls positioned side by side below said extruder die and soj that male members of the grooved surface of one roll enter and press into female members of the other roll, the rolls being so arranged that at least one polymer strand extruded through the> extruder die enters into each consol idating groove thereof; means for rotating said consol idating rolls at a greater speed than the rate of extrusion of! the polymer strands from the extruder die; means for simultaneously conveying from at least one side of the extruded curtain of polymer strands and into the nip of said consol idating rolls a plural ity of staple fiber webs, one into each consol idating groove of the rolls; and means for cool ing the material during lamination and consol idation by said rolls; said c ί rcumferent i al 1 y grooved rolls thus constituting the feed-in rolls which l inearly supply a plural ity of continuous strands or tapes of substantially consol idated staple fiber-thermoplastic polymer composite material .

8. Apparatus according to claim 6, in which said means for forming a plural ity of said continuous strands or tapes comprise: an extruder with an extruder die having a plural ity of orifices al igned in a substantially straight l ine and adapted to extrude a curtain of polymer strandk; means for stretching said polymer strands to achieve a predetermined orientation of the polymer molecules; a heater with temperature control means for passing the so oriented polymer strands therein to render them tacky on the surface while substant ially retaining their pre-viously acquired molecular or ientat ion; a pair of c i rcumferent i al 1 y grooved consol idating rolls, follow ing said heater, positioned side by side so that male members of the grooved surface of one roll enter and press into female members of the other rol 1 , said rolls being positioned so that at least one polymer stjrand coming i : out of the heater enters into each consol idat i ng groovje thereof; means for simultaneously forwarding on at least one side of the curtain of the polymer strands and into the nip of said consolidating rolls a plurality of staple fiber webs, one into each consol idating groove of the rolls; and means for cooling the i material during its lamination and consol idation by said rolls; said c ί rcumferent i a 11 y grooved rolls constituting the feed-in rolls l inearly supplying a plurality of continuous of substantially consolidated staple f iber-thermopl composite material.

9. Apparatus according to claim 5, in which the heater I has a heating fiber restrictive zone in a V-grooved form, there being as many grooves of V cross-section as there are strands or tapes to be heat treated.

10. Apparatus as claimed in claim S, in which the V shaped grooves of the heater are gradually narrowing towards the exit end of said heater, whereby the composite strands or tapes passing therethrough are simultaneously compressed for better restrictive effect and i nterbond i ng .

11. . Apparatus according to claim 5> 'n which the twist imparting device is of a false twister type adapted to rotate at speeds of up to 500,000 r.p.m. i

12. Apparatus according jto claim 5, in which the cool ing means provided between the heater a|nd the twisting device consist of a compressed air injector.

13. Apparatus according to claim 5, in which there is further provided a pair of tensioni ng rolls positioned between the twist imparting device and the [collecting roll and adapted to be driven at higher speed than that of the feed-in rolls.

14. Apparatus according to claim 5> 'n which the means for l inearly winding-up the obtained spun yarn comprise a yarn guiding member and a device for automatic replacement jof the col 1 ect i ng ro 11 s . Tel-Aviv, this 6th day of July 1969 AGENT FOR APPLICANTS