US3828537A - Production of texturised yarn - Google Patents

Production of texturised yarn Download PDF

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Publication number
US3828537A
US3828537A US00304033A US30403372A US3828537A US 3828537 A US3828537 A US 3828537A US 00304033 A US00304033 A US 00304033A US 30403372 A US30403372 A US 30403372A US 3828537 A US3828537 A US 3828537A
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yarn
zone
twist
texturising
speed
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English (en)
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W Doschko
H Rinklin
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Imperial Chemical Industries Ltd
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Imperial Chemical Industries Ltd
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    • D—TEXTILES; PAPER
    • D02—YARNS; MECHANICAL FINISHING OF YARNS OR ROPES; WARPING OR BEAMING
    • D02G—CRIMPING OR CURLING FIBRES, FILAMENTS, THREADS, OR YARNS; YARNS OR THREADS
    • D02G1/00—Producing crimped or curled fibres, filaments, yarns, or threads, giving them latent characteristics
    • D02G1/02—Producing crimped or curled fibres, filaments, yarns, or threads, giving them latent characteristics by twisting, fixing the twist and backtwisting, i.e. by imparting false twist

Definitions

  • ABSTRACT A process for producing bulk is described by sequentially drawing and false twist texturizing a synthetic yarn wherein the yarn is withdrawn from the texturizing zone at a greater speed than it is fed thereto.
  • the draw roll for the drawing step also serves as the take-off rollfor the texturizing zone and is stepped so that the portion used to take off the texturized yarn is of greater diameter than the part used for drawing.
  • the heater in the texturizing zone is a heated pin.
  • the present invention relates to improvements in or relating to the production of texturised yarn.
  • the present invention is concerned with the production of texturised yarn by the false twist principle.
  • False twisting is a technique which is used to produce a texturised effect in yarns and a false twist is conveniently acheived by first passing a moving yarn through a region where it is heated to above the second order transition temperature of the materials from which the yarn is made then allowing the yarn to cool and twisting the cooled yarn.
  • the twist imparted to the cooled yarn runs back along the yarn in the opposite direction to that in which it is travelling and into the heating zone so that the twist is set in the yarn when it moves into the cooling zone and the temperature drops below the second order transition temperature.
  • the twisting device After the yarn has passed through the twisting device, it is allowed to untwist so that the untwisting of the yarn which has been set in its twisted state results in a texturised or bulked yarn.
  • twist density we mean the number of twists per unit length in the yarn. Twist density is controlled by the nature and physical properties of the yarn supplied, ie, its chemical type, titre, number of filaments in the cross section and by the physical properties of the filaments, and also by the imposed processing conditions, namely yarn'speed, twist speed, time and temperature of heating and cooling, frictional forces in the twisting device and the nature and amount of lubricant on the surface of the yarn. It has been difficult to produce texturised yarn capable of developing a constant high level of bulk whilst having a low thermal shrinkage and an aim of our invention is to provide such a yarn and a convenient method for its production.
  • Various devices are known for imparting twist to a moving yarn.
  • the moving yarn is passed around a member which is provided within and rotates with a hollow spindle.
  • twist is inserted in the yarn as it passes through the spindle.
  • This technique is limited in the amount of twist that can be inserted in a yarn travelling at a particular speed as it is only possible to insert one twist for every rotation of the spindle.
  • Alternative techniques for imparting twist which overcome this limitation use the friction principle whereby the yarn is twisted by contact with a rotating friction surface.
  • the twist devices which use the friction principle generally consist of rotating hollow surfaces with which the moving yarn makes contact.
  • the yarn passes through the cylindrical body whereas in others the yarn enters and leaves the body from the same side and is held against the friction surface by a yarn guide.
  • the present invention is concerned with the production of texturised yarn by the friction false twist principle because this allows a greater degree of twist to be inserted into the yarn for a given speed of rotation of the twist bush and thus allows higher processing speeds to be used.
  • the roll that is used is stepped and the yarn passes around the portion of smaller diameter after passing through the texturising zone so that the yarn tension is relaxed while it is passing through the texturising unit compared to its state in the stretching zone.
  • this process results in yarn having a non-uniform and comparatively low level of bulk.
  • yarn may be partially drawn and then simultaneously texturised and drawn to complete drawing.
  • This process suffers from the disadvantage that the yarn speed and the tension in the yarn during texturising are fixed according to the required draw ratio and thus the process allows no freedom to control the yarn speed during texturising to ensure that the necessary degree of bulk is acheived.
  • this process requires a comparatively high stretch in the texturising zone which tends to remove some of the twist during heating resulting in yarn having an undesirably low level of bulk.
  • the present invention therefore provides a process for the production of texturised yarn wherein thermoplastic synthetic yarn is sequentially stretched and texturised by the friction false twist principle as hereinbefore described wherein the yarn is fed continuously from the stretching zone to the texturising zone and the yarn leaves the texturising zone at a greater speed than that at which it enters the said texturising zone.
  • the present invention is concerned only with a process where the increase in speed in the texturising zone is comparatively small and is not of the same order as speed increases generally used for stretching yarn. Whilst the actual speed increase used depends upon the particular yarn we generally fmd that it should be no greater than a 10% increase.
  • the process of the present invention may be applied to the production of yarn from any thermoplastic synthetic material which when twisted at a temperature above its second order transition temperature and then cooled whilst in its twisted state becomes set in that twisted state.
  • thermoplastic synthetic materials include Nylon 6, Nylon 6.6, polyacrylonitrile and thermoplastic polyesters such as polyethylene terephthalate.
  • the unstretched yarn first passes from a feed station to a draw roll so that the yarn is stretched between the feed station and the draw roll.
  • the yarn is then fed directly from the draw roll through a heater zone which we prefer be a pin heater around which the yarn is wrapped as this ensures quick heating and uniform heat transfer between the yarn and the heater and allows higher speed processes to be used.
  • a heater zone which we prefer be a pin heater around which the yarn is wrapped as this ensures quick heating and uniform heat transfer between the yarn and the heater and allows higher speed processes to be used. It is thought that the techniques of the present invention are particularly suited to processes using a pin heater because the slight increasse in yarn speed in the texturising zone ensures good contact between the yarn and the pin heater to give consistent heating in addition to good contact between the yarn and the friction bush to give a more constant level of twist.
  • a further advantage of using a pin heater is that the extent to which the yarn is heated may readily be altered by varying the wrap of the yarn around the heater.
  • a pin heater has the added advantage that it occupies considerably less space for the same degree of heating than the plate heaters traditionally used in processes of this type. If the increase in speed in the texturising zone is too great some of the bulk inserted by the bush will be pulled out by the high tension. If, however, there is a reduction in yarn speed during texturising the yarn will not be held sufficiently firmly against the friction bush to impart adequate twist to the yarn nor against the heater to ensure adequate setting of the twisted yarn.
  • the yarn After the yarn has passed the heater it is cooled to ensure that it is cold when it reaches the twist device, and it may be necessary to provide cooling plates which direct cold air on to the yarn, but generally we find it more convenient to ensure that the distance the yarn travels between the heater and the twist device is sufficient to cool the yarn.
  • the twisting device which may be any of the known friction devices for imparting twist to yarns, in particular twist bushes.
  • the twist imparted to the yarn runs back along the yarn to the heater so that the yarn is twisted when hot and the hot twisted yarn then cools thus setting the yarn in its twisted state.
  • the twist device provides a rotating friction surface with which the yarn is brought into contact so that the rotation of the friction surface imparts a twist to the yarn.
  • the yarn is withdrawn from the twist device in such a way that the speed of withdrawl is greater than the speed of the yarn as it is fed to the twist device.
  • the yarn is withdrawn from the twist device by the roll that is used as the draw roll of the stretching zone.
  • the roll is stepped so that the portion around which the yarn passes at the end of the draw zone is of smaller diameter than the portion around which the yarn passes after the texturising zone so that the speed of the yarn is increased between the two portions of the roll.
  • This technique is preferred as the dual functions of a single roll results in a more compact apparatus.
  • the preferred amount by which the yarn speed should be increased in the texturising zone depends upon the nature, denier and amount of twistto be inserted into the yarn. However, we have found that for certain yarns there are limits for the speed increase within which the desired high crimp rigidity is obtained. We find that these limits are generally within the elastic limit of the yarn and thus our process usually results in no permanent stretch of the yarn as it passes through the texturising zone over and above any stretch imparted by the texturising action. This is apparent by a comparison of the average decitex of the yarn produced by our preferred process with the average decitex of yarn produced by a similar process without any speed increase in the texturising zone which shows virtually no difference in the decitex of the two yarns.
  • the increase in speed may be such as to result in a slight permanent stretch but this is generally very small.
  • the preferred increase in yarn speed depends upon the particular type of yarn. However, we have found that a speed increase between 2 and 10% is to be preferred. In particular, we find that an increase in yarn speed of between 2 and 6% is suitable for the production of texturised polyamide yarn. A speed increase of this magnitude during texturising produces virtually no more permanent stretch than a similar process with no such speed increase.
  • the process of the present invention enables a yarn of high crimp rigidity to be obtained which is particularly important for yarns to be used in fabrics where fabric bulk and high elasticity are required such as for example in ladies stockings.
  • the yarns produced by our process have a sufficiently low shrinkage that a fabric made from the yarn does not alter appreciably during fabric finishing.
  • the slight speed increase in the texturising zone results in improvements in both the uniformity of the yarn obtained from one position on a machine and between the yarns obtained from different positions.
  • the crimp rigidity of a yarn is a measure of the ability of a texturised yarn to develop bulk during finishing and of the ability of the yarn to retain the bulk. The higher the crimp rigidity the greater the degree of bulk and the more elastic the yarn.
  • crimp rigidity is determined by making a loop from the texturised yarn and initially hanging a weight of 0.1 grams per decitex on the yarn and suspending the weighted skein in water at 20 C for 2 minutes. The length of the skein is then measured. The weight is then replaced by a weight of 0.002 grams per decitex and the length of the skein measured under similar conditions.
  • the crimp rigidity is the ratio of the length under a load of 0.002 grams per decitex to the length under a load of 0.1 grams per decitex expressed as a percentage.
  • twist damming element is positioned in the yarn path between the draw roll and the heater.
  • the term twist damming element refers to any system which prevents twist running along a yarn and may be a pin around which the yarn is wound although this is not preferred as such a dramatic change in yarn direction can cause filamentation and damage to the yarn.
  • a particularly useful twist damming element comprises a series of yarn guides which are preferably rolls or ceramic guides around which the yarn passes wherein the yarn path is forced to change by at least 75 as it passes around each roll.
  • twist damming element useful as it prevents the twist inserted by the twist device from running back onto the draw roll. If the yarn is twisted on the draw roll an inferior product can result as tension fluctuations in the draw zone can occur giving rise to non-uniform drawing and a variable product. Furthermore, the yarn tends to roll on the surface of the roll so that adjacent strands become intertwined, thus stopping operations. In addition if the yarn moves on the surface of a roll which controls yarn speed due to the torque imparted by texturisation the surface of the roll becomes quickly damaged.
  • the use of a twist damming element has an added advantage when used in conjunction with a pin heater as if the damming element is a movable yarn guide its position may readily be altered to provide any easy method of varying the wrap of the yarn around the pin heater.
  • the essence of our invention is therefore a continuous stretching and texturising process in which the yarn speed is increased during texturising. It should be understood that this principle may be applied to a process in which the yarn is first simultaneously stretched and texturised and then subsequently further texturised. In this embodiment the speed of the yarn will be increased during the further texturising. Similarly the texturised yarn produced by our process may be further texturised if required. Both these processes are aimed at ensuring even greater uniformity of the final bulked yarn.
  • the yarn produced by the process of this invention is a torque yarn as it has been twisted in one direction about its axis.
  • our process may be applied to two separate yarns which pass through the apparatus in parallel and are subjected to equal amounts of twist but in the opposite direction. The yarns may then be combined to form a torque free composite yarn.
  • the present invention also provides an apparatus for sequentially stretching and texturising yarn comprising a draw zone with feed means and a drawing means and a texturising zone comprising a feed roll, a heater, a friction texturising device and a withdrawing means wherein the feed roll also acts as the withdrawing means for the texturising zone and is stepped so that it is the portion of larger diameter that acts as the withdrawing means.
  • Undrawn yarn l is delivered to feed roll 2 from which it passes to the draw pin 3 and then d aw ol ..5-,Tbe. raw..ro 51 pa a d the y justed so that the yarn is stretched to the desired extent.
  • the yarn passes to heated pin 7 where it is heated to a temperature above the second order transition temperature of the material from which the yarn is made.
  • the yarn then passes to yarn guide 8 and into the friction twist bush 9.
  • the yarn path between the heated pin 7 and the pin guide 8 is sufficiently long to ensure that the yarn is no longer tacky when it passes through the guide 8.
  • the yarn passes through the bush and it is twisted by frictional contact between the inner surface of the bush and the yarn.
  • the twist imparted to the yarn runs back along the yarn towards the heated roll 7 so that the yarn is twisted while hot and the twist is set in the yarn as it cools.
  • the yarn passes from the twist bush through another yarn guide 10 to the larger diameter portion 11 of the roll 5.
  • the yarn travels around the separator roll 4, back to the portion 11 of roll 5, back to the separator roll again, through the yarn guide'8 and is wound up on the bobbin 12 by means of the ring and traveller 13;
  • the speed of the yarn is increased as it passes through the texturising zone because it is fed to the zone at the peripheral speed of the smaller portion of roll 5 and is withdrawn at the peripheral speed of the larger portion.
  • EXAMPLE I Twenty-two decitex 7 filament Nylon 66 yarn was processed using the apparatus illustrated in FIG. 1. The draw roll 5 was driven so that the portion of smaller diameter 6 was rotating at a peripheral speed of 685 metres per minute to draw the yarn to a ratio of 2.66. The twist bush 9 was rotated at a speed of about 21,500 revolutions per minute and the heated pin 7 was maintained at a temperature between 220 and 230C. the roll 5 was stepped so that the peripheral speed of the larger portion 11 was 4% greater than that of the smaller diameter portion 6.
  • the hot shrinkage of the yarn is determined by taking a 1 metre length of yarn that has been stored for at least 24 hours under normal conditions.
  • the length of yarn is made into a single loop and subjected to a tension of 18 grams/decitex and the length of the loop measured (L
  • the loop of yarn is then suspended in boiling water for minutes, dried under normal conditions for 24 hours, re-subjected to a tension of 18 grams/- decitex and the length of the loop measured (L
  • the percentage shrinkage is given by (L L )/l.. X 100.
  • the crimp rigidity of the yarn is measured by the technique previously described.
  • Example 2 The process of Example 1 was repeated but using a 44 decitex 14 filament polyamide yarn and a twist bush speed of 12,500 revolutions per minute. Several runs were carried out in which the speed at which the yarn was withdrawn from the texturising zone compared to the speed at which is was drawn off from the draw zone was varied from 6% below that at which it was withdrawn from the draw zone to 10% above that at which it was withdrawn from the draw zone. The crimp rigidity of each sample was measured by the method described above and FIG. 2 is a plot of crimp rigidity against the amount by which the yarn speed is increased through the texturising zone. As may be seen the curve passes through a peak at about 4% increase in speed.
  • Example Ill The process of Example I was repeated using a 3 filament l7 decitex polyamide yarn.
  • the draw roll 5 was 7 driven so that the portion of smaller diameterwas ro- Speed Change of Yarn Accordingly it may be seen thatin all instances the process of the present invention produced yarn of improved crimp rigidity. In addition these results show that the speed increase results in a higher yarn tension before the heater which gives rise to improved running.
  • Example IV The process of Example I was repeated using a 3 filament 17 decitex polyamide yarn.
  • the portion of the draw roll which withdraws the yarn from the draw zone was rotating at a peripheral speed of 674 metres per minute and the roll was stepped to give an 8% increase in speed between the beginning and the end of the texturising zone.
  • the temperature of the heated pin was about 230 C and the yarn thread up was such that the yarn passed once around the pin.
  • the yarn obtained contained 7,100 twists per metre, had a crimp rigidity of 41.5% and a shrinkage of 5.3%.
  • Tension measurements on the yarn during processing showed that the tension before the heater was 2.4 grams, immediately after the heater it was 6.8 grams and after the twist bush 12.5 grams.
  • a process for false twist texturing a synthetic filament yarn comprising sequentially passing the yarn being treated through a drawing zone, a twist heat setting zone, a twisting zone, an untwisting zone and a yarn speed increase zone prior to take up wherein the yarn is first drawn to the desired extent prior to passing to the twist heat setting zone and twisting zone, said yarn being twisted and the twist being passed upstream into the twist heat setting zone wherein said yarn is heated to above its second order transition temperature to set said yarn in the twisted configuration, untwisting said heat set yarn, increasing the speed of said yarn up to about percent as it passes through said heat setting and twisting zone and subsequently taking up a texturized yarn.
  • twist damming zone comprises passing the yarn through a path of'cun vature equalling at least a turn.
  • An apparatus for sequentially stretching and texturising yarn comprising a draw zone with means for feeding the yarn to a texturising zone and drawing means to withdraw the yarn from said texturising zone and to effect the required drawing of the yarn and said texturising zone comprising a feed roll, a heater, a friction texturising device providing a friction surface which bears against the yarn and a means for withdrawing the yarn wherein the feed roll also acts as the withdrawing means and is stepped so that it is the portion of larger diameter which acts as the withdrawing means.
  • An apparatus including a twist damming element with which the yarn makes contact between the heated pin and the draw roll.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Textile Engineering (AREA)
  • Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)
US00304033A 1971-11-17 1972-11-06 Production of texturised yarn Expired - Lifetime US3828537A (en)

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GB5330071 1971-11-17
GB3281372*[A GB1410596A (en) 1971-11-17 1972-07-13 Production of texturised yarn

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JP (1) JPS4861719A (enrdf_load_html_response)
BE (1) BE791321A (enrdf_load_html_response)
CA (1) CA974417A (enrdf_load_html_response)
CH (1) CH545867A (enrdf_load_html_response)
DE (1) DE2256545A1 (enrdf_load_html_response)
ES (1) ES408714A1 (enrdf_load_html_response)
FR (1) FR2161677A5 (enrdf_load_html_response)
GB (1) GB1410596A (enrdf_load_html_response)
IT (1) IT972230B (enrdf_load_html_response)
LU (1) LU66477A1 (enrdf_load_html_response)
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3938307A (en) * 1973-04-02 1976-02-17 Platt International Limited Drawing and texturing by false twist crimping of synthetic textile filament
EP1103641A1 (de) * 1999-11-25 2001-05-30 Barmag AG Verfahren zum Falschdralltexturieren eines synthetischen Fadens zu einem Kräuselgarn

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1401341A (en) * 1972-07-13 1975-07-16 Ici Ltd Production of texturised yarn

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2936567A (en) * 1955-07-19 1960-05-17 British Nylon Spinners Ltd Twisting of textile filaments
US3041814A (en) * 1960-07-07 1962-07-03 Heberlein Patent Corp Apparatus for producing crimped yarn
US3069837A (en) * 1959-06-30 1962-12-25 Du Pont Twisting process
US3178795A (en) * 1962-10-10 1965-04-20 Deering Milliken Res Corp Method for edge crimping thermoplastic yarns
US3365874A (en) * 1963-11-12 1968-01-30 Monsanto Co Treatment of synthetic filaments
US3432355A (en) * 1962-10-24 1969-03-11 Gen Electric Polytetrafluoroethylene coated and bonded cell structures
US3645081A (en) * 1969-10-31 1972-02-29 Spinner Oy Machine for crimping thermoplastic filament
US3651633A (en) * 1970-10-27 1972-03-28 Fiber Industries Inc Flange false twist textured nylon
US3729916A (en) * 1971-03-30 1973-05-01 Beaunit Corp Method for treating yarn

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2936567A (en) * 1955-07-19 1960-05-17 British Nylon Spinners Ltd Twisting of textile filaments
US3069837A (en) * 1959-06-30 1962-12-25 Du Pont Twisting process
US3041814A (en) * 1960-07-07 1962-07-03 Heberlein Patent Corp Apparatus for producing crimped yarn
US3178795A (en) * 1962-10-10 1965-04-20 Deering Milliken Res Corp Method for edge crimping thermoplastic yarns
US3432355A (en) * 1962-10-24 1969-03-11 Gen Electric Polytetrafluoroethylene coated and bonded cell structures
US3365874A (en) * 1963-11-12 1968-01-30 Monsanto Co Treatment of synthetic filaments
US3645081A (en) * 1969-10-31 1972-02-29 Spinner Oy Machine for crimping thermoplastic filament
US3651633A (en) * 1970-10-27 1972-03-28 Fiber Industries Inc Flange false twist textured nylon
US3729916A (en) * 1971-03-30 1973-05-01 Beaunit Corp Method for treating yarn

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3938307A (en) * 1973-04-02 1976-02-17 Platt International Limited Drawing and texturing by false twist crimping of synthetic textile filament
EP1103641A1 (de) * 1999-11-25 2001-05-30 Barmag AG Verfahren zum Falschdralltexturieren eines synthetischen Fadens zu einem Kräuselgarn
US6477828B1 (en) 1999-11-25 2002-11-12 Barmag Ag Method of false twist texturing a synthetic yarn to a crimped yarn

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FR2161677A5 (enrdf_load_html_response) 1973-07-06
AU4839872A (en) 1974-05-16
CA974417A (en) 1975-09-16
NL7215020A (enrdf_load_html_response) 1973-05-21
IT972230B (it) 1974-05-20
BE791321A (fr) 1973-05-14
GB1410596A (en) 1975-10-22
CH545867A (enrdf_load_html_response) 1974-02-15
ES408714A1 (es) 1976-03-16
LU66477A1 (enrdf_load_html_response) 1973-02-01
DE2256545A1 (de) 1973-05-24
JPS4861719A (enrdf_load_html_response) 1973-08-29

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