HIGH BULK YARN AND METHOD OF MANUFACTURING THEREOF

Abstract

A method of manufacturing high bulk continuous multi-filament yarn comprises a number of distinct steps. In a first step, a plurality of filaments of polymer are melt spun to form a partially oriented yarn (POY). In a second step, the POYs are drawn and textured to form a draw textured yarn, wherein texturing is carried out in a friction texturing process. Subsequently at least two plies of the draw textured yarn are twisted and/or cabled together and subsequently heat set to obtain the high bulk continuous multifilament yarn.

Claims

1. A method of manufacturing a high bulk continuous multifilament yarn for use as pile in a floor covering, comprising: in a first step, melt spinning a plurality of filaments of polymer to form a partially oriented yarn; in a second step, drawing and texturing one or more partially oriented yarns in a friction texturing process to form a draw textured yarn; and in a third step, twisting or cabling at least two plies of the draw textured yarn together in a range between 30 and 400 twists per meter and heat setting the twisted plies to obtain the high bulk continuous multifilament yarn having a weight of at least 1000 denier, wherein at the end of the second step and prior to the third step, the draw textured yarn is wound to a bobbin or hank.

2. The method according to claim 1, wherein the method includes an intermediate step after the second step, wherein two, three or four draw textured yarns are intermingled together to form a single ply of draw textured yarn.

3. The method according to claim 1, wherein the drawing and texturing is performed at a temperature in a range between 130 C. and 200 C.

4. (canceled)

5. The method according to claim 1, wherein the heat setting is performed at a temperature in a range between 80 C. and 220 C.

6. The method according to claim 1, wherein the first step includes quenching of the partially oriented yarn and wherein, an effective quench length is in more than 1.2 m.

7. The method according to claim 1, wherein the plies of draw textured yarn each have a weight of more than 500 denier.

8. The method according to claim 1, wherein the high bulk yarn has a bulk of at least 12 cm.sup.3/gm.

9. The method according to claim 1, further comprising applying a frieze effect to the high bulk continuous multifilament yarn.

10. (canceled)

11. (canceled)

12. The method according to claim 1, wherein, the friction texturing is carried out with a friction disk at a friction disk diameter to yarn speed (D/Y) ratio of greater than 1.5.

13. The method according to claim 1, wherein the filaments in the partially oriented yarn at completion of the first step have a weight of greater than 2 denier per filament (dpf).

14. The method according to claim 1, wherein the first step takes place at a speed that is at least double the speed of the second step.

15. The method according to claim 1, wherein heat setting the twisted plies to obtain the high bulk continuous multifilament yarn takes place in a fourth step subsequent to twisting or cabling the at least two plies of the draw textured yarn together.

16. (canceled)

17. A high bulk yarn for use as pile in a floor covering comprising a plurality of plies, wherein; each ply further comprises at least one draw textured yarn and wherein, the at least one draw textured yarn further comprises continuous filaments of polymer wherein, the at least one draw textured yarn is false-twist friction textured; the plurality of plies are twisted or cabled together in a range between 30 and 400 twists per meter and heat set in the twisted or cabled state, wherein a weight of the high bulk yarn is at least 1000 denier, and the bulk of the high bulk yarn is at least 12 cm.sup.3/gm.

18. The high bulk yarn according to claim 17, wherein the filaments are single-component filaments.

19. The high bulk yarn according to claim 17 having a weight of greater than 2000 denier.

20. The high bulk yarn according to claim 17, wherein the high bulk yarn has a bulk of at least 16 cm.sup.3/gm.

21. The high bulk yarn according to claim 17, wherein the polymer includes at least one of a polyethylene terephthalate (PET) and a polybutylene terephthalate (PBT).

22. The high bulk yarn according to claim 17, wherein a weight of the filaments is greater than 2 dpf.

23. A floor covering material comprising: a base backing; and a pile comprising a high bulk yarn that is tufted, knitted, knotted or woven to the base backing, wherein the high bulk yarn comprises a plurality of plies of false-twist friction textured yarn formed from continuous filaments of polyester, wherein the plurality of plies are twisted or cabled together in a range between 30 and 400 twists per meter and heat set in the twisted or cabled state, such that a weight of the high bulk yarn is at least 1000 denier and the bulk of the high bulk yarn is at least 12 cm.sup.3/gm.

24. (canceled)

25. The floor covering material according to claim 23 wherein, the high bulk yarn is cut to form a cut pile floor covering material.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The features and advantages of the present disclosure will be appreciated upon reference to the following drawings of an of exemplary embodiment, in which:

[0035] FIGS. 1A to 1E show in schematic view, steps of a method according to the invention;

[0036] FIG. 2 shows a cross-section through a high bulk yarn produced according to the method of FIG. 1; and

[0037] FIG. 3 shows a cut-pile tufted carpet incorporating the yarn produced according to the method of FIG. 1.

DESCRIPTION OF EMBODIMENTS

[0038] The following detailed description illustrates an embodiment of the present disclosure and ways in which they can be implemented. Although some modes of carrying out the present disclosure have been disclosed, those skilled in the art would recognise that other embodiments for carrying out or practising the present disclosure are also possible.

[0039] FIG. 1 shows steps of a method for manufacturing a high bulk yarn according to an exemplary embodiment of the invention. It will be understood that the numbers and values given are of one specific example and many alternative process parameters may be applied.

[0040] In a first step, according to FIG. 1A, a plurality of continuous filaments 1 of polyester are extruded from an extruder 10. The filaments 1 are quenched in a quench chamber 24 and drawn over rollers 20 for making a partially oriented yarn (POY) 2. The quench chamber 24 has an effective quench length E of 1.8 m and a quenching air speed in the chamber is set to 0.9 m/s for completing a process of cooling and solidifying the filaments 1. The effective quench length E is defined between the extruder 10 and spin finish applicators 18. The filaments 1 are spin-drawn to have a weight of 10 denier per filament (dpf). In total, 24 filaments 1 are wound together as the POY 2 to a first bobbin 3 with an overall denier of 240.

[0041] In a second step shown in FIG. 1B, two first bobbins 3, each wound with the POY 2 of continuous polyester filaments 1, are combined together and draw-textured in a double-density friction texturing machine 40. The POYs 2 are guided by a number of rollers starting with input rollers 41 to friction disks 47. The friction disks 47 twist the POYs 2 in a section between the input rollers 41 and the friction disks 47. In the same section, the POY 2 passes through a first heater 43 that heats the twisted POYs 2 to a temperature of 180 C. in order to apply the twist. A D/Y ratio of 1.9 is used in the texturing process. Central rollers 45 are placed after the first heater 43 to draw the twisted POYs at a draw ratio of 1.7 and to form a draw textured yarn 4. Due to the draw texturing process, a weight of individual filaments of the draw textured yarn reduces to around 60% of the weight of the POY filaments 1 to a value of around 6 dpf. The draw textured yarn 4 is then guided to a second heater 49 and overfeed rollers 51 which cause the draw textured yarn 4 to overfeed in order for crimps to develop and set. It has however been found that the second heater may be omitted or set to a lower temperature, since adequate heat setting is applied in the subsequent steps. The resulting draw textured yarn 4 with a weight of around 300 denier is wound to a third bobbin 6.

[0042] In FIG. 1C are shown four third bobbins 6 carrying the draw textured yarn 4 which are intermingled in an intermingling jet 50 to form a single ply 5. The ply 5 has a weight of 1200 denier and is wound to a fourth bobbin 8. In this example, intermingling is performed as a separate step from bobbin to bobbin. This allows it to take place independently at an optimal speed. It will be understood that it can also be implemented at the back end of the draw-texturing step, with a number of draw textured yarns 4 being intermingled prior to winding to the third bobbin 6.

[0043] In a third step, shown in FIG. 1D, two plies 5a,b from two fourth bobbins 8a,b are twisted/cabled together to form a high bulk yarn 7 having a weight of 2400 denier. A cover ply 5b is twisted around a core ply 5a by rotating a cover bobbin 8b around a core bobbin 8a as shown in the figure by rotation R. The core ply 5a remains untwisted in the process. The plies 5a,b are twisted/cabled at 110 twists per meter (TPM) and wound to a fifth bobbin 9.

[0044] In a next step, shown in FIG. 1E, three fifth bobbins 9 with the high bulk yarn 7 are simultaneously guided to a frieze box 60 for achieving additional bulk and then to a heat setting tunnel 70 wherein the high bulk yarn 7 stabilizes at a temperature of around 170 C. Each of the three exiting heat-set high bulk yarns 7 is wound to a separate sixth bobbin 13.

[0045] FIG. 2 shows a cross-section through the high bulk yarn 7 of FIG. 1E, illustrating the two plies 5. Each of the plies 5 is formed of four draw textured yarns 4, wherein each of the draw textured yarns 4 is further composed of two POYs 2, each having 24 continuous filaments 1. It will be understood that the cross-section is purely illustrative and that in actual fact, the individual POYs will no longer be discernible.

[0046] FIG. 3 shows a cut-pile tufted carpet 100. The carpet 100 has a woven backing 102, into which are tufted the high bulk yarns 7 as illustrated in FIGS. 1 and 2. The yarns 7 form upstanding threads 104.

EXAMPLES

[0047] The comparison between carpets made from yarns according to the present invention and the conventional yarns is shown in Table 1. In the table properties of the yarn such as a material, weight, weight of the filaments, and bulk are listed together with the properties of the carpet such as gauge, stitch rate and pile properties. The last columns show performances of each carpet in a Hexapod test as well as an overall rating of the carpet. The overall rating is assessed by a group of independent users who compared carpets based on their appearance and quality. All carpets are constructed to have approximately the same coverage of around 1050 grams per square meter (GSM) and consist of PET filaments. Further, the conventional carpets are compared with the carpets according to the present invention having a lower coverage. The assessment is performed using the conventional carpets as a standard and the independent users rated a feel and a look of the carpets according to the present invention with respect to the conventional carpets. The feel is linked to the coverage of the carpet as the lower coverage would result in users pressing onto a base backing of the carpet which is harsh and unpleasant to walk on. The look on the other hand is linked to the bulk of the carpet. High bulk of the yarn results in more luxurious look of the carpet.

[0048] The hexapod rating represents the rating achieved by the sample during the Hexapod drum test at 4000, 8000, and 12000 cycles. The Hexapod rating as referenced throughout the present specification is obtained using the D 5252-98a (2003) standard for the operation of the Hexapod tumble drum tester of 3.8 kg weight. The test was performed using a standard, upright type vacuum cleaner as supplied with the Hexapod drum tester. The Hexapod drum test include a rotating drum used as an instrument to test pile floor coverings. Carpet samples are placed in this rotating drum with a polyurethane studded metal ball to simulate the physical effects of traffic. This accelerated test provides a specific rating of the ability of the carpet to withstand crushing and matting.

[0049] The Hexapod test measures the resiliency of the carpets and, as shown in Table 1, the carpets according to the present invention are superior to the carpets with conventional PET yarns of similar denier-filament range. The 12000 Hexapod rating of the carpets comprising high bulk yarns is up to 2.5 while the conventional carpets show a rating of only 1. The results show that the fibres are less likely to collapse upon longer use due to a higher bulk that prevents fibre-crashing.

[0050] Yarn bulk is measured in units of cc/gm which is reversed to the unit of density. The bulk is measured using a Yarn Bulkometer by WIRA instrumentation having a chamber of size 10060 mm. In the process, an aligned hank of yarn with known weight and length is placed inside the bulkometer. The chamber is closed and the hank is pressed with an evenly distributed weight of 0.5 kg. A volume of the measured portion of the hank is measured and the bulk is calculated as a ratio of the volume and the weight per unit of length.

[0051] As shown in the Table 1, the high bulk yarn according to the present invention clearly exhibits much higher bulk values compared to the conventional BCF yarns available in the similar denier range. Additionally, it is observed that the yarns according to the present invention offer comparable or slightly improved results even when the constructed carpets have much lower gsm than the conventional carpets. The rows 9-11 in Table 1 show carpets made with relatively low coverage of only 800 gsm compared to carpets with regular PET BCF yarns having the coverage of 1040 gsm. However, both, the user assessment and the Hexapod rating, show comparable or even better results of the carpets according to the present invention. Therefore, the high bulk yarns according to the present invention may be advantageous over the other products even with lower values of the coverage. It should be noted that the improved results are achieved for both the frieze and the straight yarns.

[0052] Thus, the invention has been described by reference to certain examples discussed above. It will be recognized that these embodiments are susceptible to various modifications and alternative forms well known to those of skill in the art. In particular, different initial filament weights may be employed according to the intended use. Many modifications in addition to those described above may be made to the structures and techniques described herein without departing from the spirit and scope of the invention. Accordingly, although specific embodiments have been described, these are examples only and are not limiting upon the scope of the invention.

TABLE-US-00001 TABLE 1 Comparison of properties between regular products and high bulk yarn of the present disclosure Final Carpet Construction Yarn Pile Carpet Bulk and Yarn Details Twist Bulk Height Cut/ Hexapod rating coverage after Type Denier Filament DPF & HS (cc/gm) Guage Stitch (mm) GSM Loop 4000 8000 12000 backcoating PET 1200 120 10 2 ply 188Z 10.5 48 12 1040 Cut 3.5 1 1 Standard BCF Friese Heat Set PET 1325 144 9 2 ply 185S 11.5 48 12 1040 Cut 3.5 1 1 Standard BCF Friese Heat Set High 1200 190 6.3 2 ply 190Z 16.6 31 16 1050 Cut 4 3.5 2.5/2 Significantly Bulk Friese higher bulk and Heat set more coverage 36 14 Cut 3.5 3 2/1.5 Significantly higher bulk and more coverage 42 12 Cut 4.0/3.5 2.5/2.0 2 Significantly higher bulk and more coverage 26 16 900 Cut 3 2.5 1 Higher bulk and coverage 30 14 Cut 3.5 3/2.5 2/1.5 Higher bulk and coverage 39 12 Cut 3 2.5 1.5 Higher bulk and coverage 23 16 800 Cut 3.5 2.5/2.sup. 1 Comparable 26 14 Cut 3.5 2.5 1.5 Comparable 34 12 Cut 3 1.5/1.0 Higher bulk and coverage 1200 190 6.3 2 ply 190Z 16.3 31 16 1050 Cut 4 3.5 2.5/2 Significantly Straight higher bulk and Heat set more coverage