WO2023203482A1

WO2023203482A1 - High bulk yarn and method of manufacturing thereof

Info

Publication number: WO2023203482A1
Application number: PCT/IB2023/053955
Authority: WO
Inventors: Abhishek Mandawewala
Original assignee: Aym Syntex Ltd
Priority date: 2022-04-19
Filing date: 2023-04-18
Publication date: 2023-10-26

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.

Description

HIGH BULK YARN AND METHOD OF MANUFACTURING THEREOF

Field of the invention

[0001] The present invention relates to the textile industry and more specifically, to a method of manufacturing high bulk yarns, as well as, the high bulk yarns and floor covering materials made from the aforementioned high bulk yarns.

Background art

[0002] Bulk Continuous Filament (BCF) yarns have many applications in a day-to-day life. One such application is carpet manufacturing. However, in order to satisfy requests of the carpet industry, the BCF yarns have to be strong and resilient but at the same time to offer an acceptable feel, look and coverage of a final product. To meet these demands, the manufacturers are forced to produce dense carpets with high grams per square meter (GSM) coverage, which results in high consumption of material and high costs of the final product.

[0003] Reducing the GSM is not an option as it directly affects the quality of the final product. Another option is to increase the bulk of the BCF yarn by texturing. It should however be noted that BCF yarn has usually been almost fully drawn or fully drawn by passing over hot godets following the extrusion process. In this condition, the yarn may be termed highly oriented yarn (HOY) or fully drawn yarn (FDY). Friction texturizing processes cannot be effectively applied as these rely on further extension of the yarn. Instead, BCF yarns are traditionally textured using a staffer box texturing method wherein, the yarn after the extrusion and drawing process is placed into a staffer box machine and axially compressed. The staffer box typically includes two friction feed rolls which force the yarn into a cavity, where it is crimped in a special atmosphere while a restrained gate exerts rearward pressure on the yarn. This is a single step process, i.e. it takes place in-line with the extrusion process at effectively the same speed.. However, the resulting textured yarn does not meet requirements of the carpet industry as the obtained bulk is not high enough and random in nature. Consequently, the coverage of the carpet obtained with such yarn remains poor. To make up for poor coverage, stitch rate, gauge, pile height and yarn denier may be increased but all of these adaptations are sub-optimal. An example of such a BCF yarn is given in EP 0547176 B1

[0004] Therefore, it would be advantageous to provide yarns that offer more efficient use of the material in order to improve the coverage while maintaining the feel, look, and overall quality of the final product. Summary of the invention

[0005] According to a first aspect of the present invention, there is provided a method of manufacturing a high bulk continuous multifilament yarn as defined in claim 1 . The method comprises:

1 . in a first step, melt spinning a plurality of filaments of polymer to form a partially oriented yarn (POY);

2. in a second step, drawing and texturing one or more partially oriented yarns to form a draw textured yarn, wherein texturing is carried out in a friction texturing process; and

3. in a third step, twisting and/or cabling at least two plies of the draw textured yarn together and heat setting the twisted plies to obtain the high bulk continuous multifilament yarn.

The resulting continuous multifilament yarn has a much improved bulk compared to BCF yarns. This ensures that when integrated into a carpet or floor covering, for the same denier, better coverage can be achieved.

[0006] Throughout the present disclosure, the term “step" refers to a stage of a multistaged process in which different stages are performed on different machines in an ordered manner such that a subsequent step (such as a second step) is performed after completion of a previous step (such as a first step). The step may include a plurality of (sub-)processes but an end of each step is marked by winding the yarn to a bobbin or a hank or similar and/or by moving the yarn from one machine to another. Thus for a multi- step process, each step is independent from the other in terms of speed, whether measured in linear terms or mass terms. Furthermore, a failure, stoppage or error in one step need not cause another step to be interrupted. In the present case, the first step may take place at a speed that is higher than the second step, preferably at least double, or more than 3 times higher or 5 times higher or up to 10 times higher, with the speed being measured at the completion of the step. The first step may also be completed by winding the POY to one or more reels or bobbins.

[0007] As stated above, the first step comprises melt spinning the plurality of filaments by extruding the melted polymer using a spinneret to form the partially oriented yarn (POY). The POY is a yarn that comprises filaments that are only partially drawn and crystalized. The polymer may include at least one of a polyethylene terephthalate (PET) and a polybutylene terephthalate (PBT). The weight of each of the filaments may be greater than 2 denier per filament (dpf) or greater than 3 dpf or greater than 7 dpf and may also be greater than 12 dpf, or greater than 15 dpf, or even greater than 20 dpf. A value of 10 dpf has been found optimal. An upper value has not been identified but will generally be less than 50 dpf. Such a high weight of the filaments is not conventional in the POY, where filaments are more generally used in the range of 0.5 dpf to 3 dpf. However, the presently proposed higher weight is believed to be crucial for carrying out the present invention, as will be discussed further below.

[0008] After extrusion, the filaments are cooled in a quench chamber. Due to the relatively larger thickness of the extruded filaments compared to the conventional POY, a length of the quench may have to be increased from a conventional short quench of around 1 m to allow for a significantly longer quench length. The effective quench length may be more than 1 .2 m, preferably more than 1 .5 m or more than 1 .8 m. An air flow speed in the quench chamber may be increased to at least 0.9 m/s to further improve efficiency of the cooling process of the filaments.

[0009] For the purpose of the present specification, reference to the effective quench length is taken to be the distance between the spinneret and a spin-finish applicator. The increased effective quench length is necessary to allow for a completion of the cooling process due to the large weight and relatively smaller surface area of the high dpf filaments. The cooled POY may be wound to a bobbin after which the first step ends. It should be added, that the POY process may include additional treatments, including an air-nip to lightly entangle the filaments and maintain the coherency of the yarn for winding and unwinding.

[0010] The POY obtained in the first step may have a weight of from 100 denier to 1000 denier, preferably between 200 denier and 400 denier and optionally around 240 denier. Given the relatively heavy weight of the filaments, it may comprise from 10 to 500 filaments, optionally around 25 filaments.

[0011] The second step comprises simultaneously drawing and texturing at least one POY obtained in the first step to create the draw textured yarn. The second step may also commence by unwinding the POY from one or more bobbins.

[0012] Drawing and texturing processes are generally conventional for providing bulk to POY. According to the invention, this is carried out in a friction texturing process also known as a false twist texturing or friction disk texturing. In the friction texturing process, the yarn is first heated and then passes between a number of partially overlapping disks that rotate about an axis generally parallel to the yarn axis as it is being drawn. These insert a twist into the yarn. Depending on a configuration of the disks, the texture may be S- or Z-twist yarn. In conventional texturising processes, the yarn then may pass through a second heater unit which heats the yarn to a temperature where it can be heat-set to obtain a more stable yarn. In the procedure according to the present invention, this step of heat setting after the friction texturing stage may be omitted, since the yarn will be heat- set in a subsequent step. Omitting or reducing the temperature of this step can not only save considerable energy but it also avoids a reduction in yarn bulk that the heating can cause. In some cases, this secondary heating may be limited to below 160 C or below 140 C or below 120 C or below 100 C.

[0013] In the friction texturing process a diameter-to-yarn-speed ratio, i.e. a D/Y ratio, is an important parameter that determines a degree of twist applied to the textured yarn. This represents the ratio between the transverse speed at the outer circumference of the friction disk that engages with the yarn and the yarn speed. It should be noted that the actual speed at which the friction texturing is performed is significantly lower than the speed at which the step of melt spinning the filaments is run. Consequently, friction texturing and melt spinning are difficult to perform in a single step. For this reason, the created POY is wound to a bobbin and then friction textured in a following step. This is substantially different from a common BCF yarn manufacturing process where stuffer box texturing is performed in the same step as the melt spinning and drawing as these processes run at same speeds. Further, it may be noted that friction textured yarns result in a helical three- dimensional crimp which is desirable for floor covering applications as it can provide more uniform bulk over the whole area of the material. Yarns textured using a stuffer box texturing lead to crimping that is highly non-uniform in nature. The friction texturing step may be carried out at between 500 m/min and 1000 m/min, preferably at below 700 m/min. It will be understood that by reducing the linear speed, the D/Y ratio can be increased. In contrast, typical speeds at which the POY is produced in the first step may be well above 1000 m/min or more than 2000 m/min and as high as 3500 m/min.

[0014] The second step may be performed at appropriate conditions such as for a temperature and the D/Y ratio. The temperature for the drawing and texturing may be in a range between 130°C and 230°C or from 160°C to 230°C , preferably between 170°C and 200°C, and more preferably between 170°C and 190°C or between 180°C and 200°C. The D/Y ratio may be in a range between 1.5 and 2.5, preferably between 1.7 and 2.3, more preferably between 1.85 and 2. Conventional POY comprising low dpf filaments are believed to be unable to withstand such high transverse speeds of the friction disks and the resulting high false-twist in the texturing process. This would lead to unacceptable levels of breakage. In should be noted that in the second step, a final weight of the yarn is reduced to about 60% of the weight of the POY. Thus initial POY filaments of 3 dpf would be reduced to 2 dpf and POY filaments of 10 dpf would be reduced to around 6 dpf. According to the present invention, it has been found that the heavier weight POY obtained in the first step is able to accept a much higher degree of texturing. At the end of the second step, the draw textured yarn may be wound again to the bobbin or the hank, preferably without first heat- setting.

[0015] Only one POY may be textured and wound to the bobbin or the hank to create a single-density draw textured yarn. However, two, three or more POY may be simultaneously drawn and textured to create a double-density, triple-density or multidensity draw textured yarn. Double-density texturing with two POY twisted in opposite directions (S- and Z-twist) is preferred because it results in a draw textured yarn without residual torque. Further, the multi-density draw textured yarns have more bulk compared to the single-density draw textured yarn. A weight of the draw textured yarn may be in a range between 200 and 600 denier, preferably around 300 denier.

[0016] As an optional step following the second step, at least two draw textured yarns may be intermingled together to form a single ply. Preferably, four draw textured yarns are intermingled together. The yarns may be nipped or lightly twisted for improved overall stability of the ply but this is optional. The purpose of intermingling is to achieve a sufficiently high weight in the plies intended for the subsequent step. A weight of the intermingled draw textured ply may be in a range of 400 to 2400 denier, preferably greater than 500 denier, e.g. between 1000 and 1500 denier. Intermingling can also take without a separate step e.g. by combining multiple yarns exiting from the draw texturing process, without first winding to a bobbin. Nevertheless, a separate step is preferred, running independently of the draw texturing process, e.g. from bobbin to bobbin.

[0017] After the second step and the optional intermingling step, follows the third step wherein, at least two plies of the draw textured yarn are twisted and/or cabled together. Each of the plies may be greater than 500 denier. The twisting and/or cabling may be performed in a range between 30 and 400 twists per meter (TPM), preferably between 110 and 250 TPM, more preferably between 110 and 210 TPM or from 110 to 200 TPM. During the twisting, the yarn may be imparted with permanent and distinctive texture in the form of twists. It will be appreciated that twisting together a number of plies may be advantageous in terms of creating an additional bulk in the yarn.

[0018] The twisted draw textured yarn is subsequently heat set. e.g. by passage through a heated medium such as air, steam or a liquid. In the process, a heat is transferred from the medium to the twisted yarn as the yarn passes through a heat setting device. A temperature of the medium may be chosen such that the yarn does not melt. Alternatively, if the temperature of the medium is above the melting point of the yarn, then an exposure time, or a dwell time, is shortened to prevent the yarn from melting. The heat setting may be performed at a temperature in a range between 85°C and 220°C, preferably between 1 10°C and 190°C, more preferably between 160°C and 180°C. The dwell time may be in a range between 50 s and 80 s. It will be appreciated that heat setting stabilizes the twist in the yarn and eliminates undesirable torquing. Moreover, heat setting does not result in loss of resilience and overall appearance of the yarn.

[0019] It is not excluded that the heat setting is carried out in the same step of the method as the twisting and/or cabling. Nevertheless, it is preferred that the heat setting is carried out in a separate step. Heat setting may take place at a much higher speed than the twisting and/or cabling and it may be desirable to first wind the twisted yarn to a reel or bobbin and perform heat setting in a subsequent step. For this purpose, a large number of bobbins may be provided in a creel and delivered to a heat setting apparatus such as an apparatus using saturated or superheated steam. Preferably, the heat setting takes place with the yarn in a relaxed state. For such continuous processes, the heat-set temperature may be between 1 10 C to 220 C. Discontinuous heat setting processes may also be applicable such as autoclaving but these should also preferably be carried out in the relaxed state i.e. with the yarn in a hank rather than tightly wound as on a bobbin. For a discontinuous process, heat-setting may take place at a temperature of from 80 C to 130 C.

[0020] After twisting and/or cabling, the yarn may also be subjected to a frieze process in order to provide additional bulk. The frieze process may be applied in a frieze box in a continuous process as part of the heat setting process.

[0021] The high bulk continuous multifilament yarn obtained following the method described above has a bulk of at least 12 cm³/gm, preferably at least 14 cm³/gm and more preferably as least 16 cm³/gm. This is significantly higher than for the conventional textured BCF yarns. The overall weight of the yarn will be greater than 1000 denier and generally will be greater than 1500 denier or even greater than 2000 denier. The present invention is advantageous as it provides yarn with high bulk resulting in lower consumption of raw material for manufacturing of an end product and consequently, reducing the manufacturing costs. The high bulk yarns of the present invention may result in 20-50% lower material consumption compared to conventionally bulked continuous filament yarns without affecting the properties of an end product such as the look, the feel and the coverage. Moreover, the high bulk yarns according to the present invention have been shown to have superior resilience compared to the conventional bulked continuous filament yarns. Bulk is measured using a standard bulkometer such as available from Wira Instrumentation Ltd. Measurement takes place with a 500g load applied over an area of 100 mm x 60 mm. [0022] In another aspect of the present invention, a high bulk continuous multifilament yarn is provided wherein the high bulk continuous multifilament yarn is obtained using the method according to the first aspect of the present invention.

[0023] In a further aspect of the present invention, a high bulk continuous multifilament yarn is provided. The high bulk continuous multifilament yarn comprises a plurality of plies wherein, each ply further comprises at least one draw textured yarn. The draw textured yarn may be obtained using the method steps and processes described above and hereinafter. The draw textured yarn may refer to a yarn having a helical three-dimensional crimp. Alternatively or additionally, the draw textured yarn may comprise false twists wherein the false twists are obtained in a friction texturing process. The draw textured yarn may further comprise one or more partially oriented yarns (POY) wherein, each of the partially oriented yarns comprises a plurality of continuous filaments of polymer. A weight of the filaments of the POY may be greater than 2 dpf or greater than 3 dpf or greater than 5 dpf or greater than 7 dpf, or greater than 10 dpf, or greater than 12 dpf or even greater than 15 dpf prior to draw texturing. Upon draw-texturing the POY, draw textured filaments may have a final weight greater than 2 dpf or greater than 3 dpf or greater than 4 dpf, or greater than 6 dpf, or greater than 7.5 dpf or even greater than 9 dpf. A bulk of the high bulk continuous multifilament yarn may be at least 12 cm³/gm, preferably at least 14 cm³/gm, more preferably at least 16 cm³/gm.

[0024] In preferred embodiments, the two or more plies of the high bulk continuous multifilament yarn are twisted and or cabled together and heat set. Optionally, they may be provided with an additional frieze treatment. The resulting high bulk continuous multifilament yarn may have an overall weight of greater than 1000 denier, preferably more than 1500 denier and more preferably greater than 2000 denier, such as between 1800 denier and 4000 denier.

[0025] In an embodiment, the high bulk yarn according to the present invention comprises single-component filaments. In other words, the filaments forming the high bulk yarn are made of a single component or material. The high bulk single-component yarn according to an embodiment of the present disclosure would also be advantageous in terms of providing an easier end product to recycle. Preferred materials include polyesters including but not limited to a polyethylene terephthalate (PET) and a polybutylene terephthalate (PBT)

[0026] Alternatively, the high bulk yarn may be multi-component yarn. In this case, the filaments may be side by side or core-sheath filaments of two or more different materials. The filaments may comprise e.g. a combination of PET and PBT or any other suitable and beneficial combination of materials. [0027] In a further aspect of the present invention, a floor covering material is provided comprising a base backing and a pile comprising the high bulk continuous multifilament yarn according to present invention. The floor covering material may include, but is not limited to, carpets, rugs, mats and so forth.

[0028] The high bulk yarn may be tufted into the base backing to form the floor covering material. Alternatively, the high bulk yarn may be knitted, knotted, or woven into the base backing to form the floor covering material.

[0029] In an embodiment, the high bulk yarn is cut to form a cut pile floor covering material. Alternatively, the high bulk yarn may be used in the form of a loop pile.

[0030] The floor covering materials according to present invention are advantageous with respect to similar, prior art materials as they offer soft feel, luxurious look, and higher resilience while lowering the weight and raw materials consumption of the end product.

Brief description of the drawings

[0031] The features and advantages of the present disclosure will be appreciated upon reference to the following drawings of an of exemplary embodiment, in which:

[0032] Figures 1A to 1 E show in schematic view, steps of a method according to the invention;

[0033] Figure 2 shows a cross-section through a high bulk yarn produced according to the method of Figure 1 ; and

[0034] Figure 3 shows a cut-pile tufted carpet incorporating the yarn produced according to the method of Figure 1 .

Description of embodiments

[0035] 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.

[0036] Figure 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.

[0037] In a first step, according to Figure 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.

[0038] In a second step shown in Figure 1 B, 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.

[0039] In Figure 1 C 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.

[0040] In a third step, shown in Figure 1 D, 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.

[0041] In a next step, shown in Figure 1 E, 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.

[0042] Figure 2 shows a cross-section through the high bulk yarn 7 of Figure 1 E, 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.

[0043] Figure 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 Figures 1 and 2. The yarns 7 form upstanding threads 104.

Examples

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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 100x60 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.

[0048] 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.

[0049] 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 1 : Comparison of properties between regular products and high bulk yarn of the present disclosure

Claims

1 . A method of manufacturing a high bulk continuous multifilament yarn, 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 and/or cabling at least two plies of the draw textured yarn together and heat setting the twisted plies to obtain the high bulk continuous multifilament yarn.

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

3. The method according to claim 1 or 2 wherein, the drawing and texturing is performed at a temperature in a range between 130°C and 200°C.

4. The method according to any preceding claim wherein, the twisting and/or cabling is performed in a range between 30 and 400 twists per meter (TPM).

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

6. The method according to any preceding claim wherein, the first step includes quenching of the partially oriented yarn and wherein, an effective quench length is in more than 1 .2 m, preferably more than 1 .5 m or more than 1 .8 m.

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

8. The method according to any preceding claim wherein, the high bulk yarn has a bulk of at least 12 cm³/gm, preferably at least 14 cm³/gm and more preferably at least 16 cm³/gm.

9. The method according to any preceding claim further comprising applying a frieze to the high bulk continuous multifilament yarn, preferably in a frieze box.

10. The method according to any preceding claim wherein, the polymer includes at least one of a polyethylene terephthalate (PET) and a polybutylene terephthalate (PBT).

1 1. The method according to any preceding claim wherein, the filaments are single component filaments.

12. The method according to any preceding claim 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, preferably greater than 1 .7 and more preferably greater than

1.9.

13. The method according to any preceding claim, wherein the POY filaments at completion of the first step have a weight of greater than 2 denier per filament (dpf) or greater than 3 dpf or greater than 7 dpf, or greater than 12 dpf,

14. The method according to any preceding claim, wherein the first step takes place at a speed that is higher than the second step, preferably at least double, or more than 3 times higher or 5 times higher or up to 10 times higher.

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

16. A high bulk continuous multifilament yarn obtainable using the method according to any one of the preceding claims.

17. A high bulk yarn 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 one or more partially oriented yarns, each comprising continuous filaments of polymer wherein, the at least one draw textured yarn is friction textured to have a helical texture; the plurality of plies are twisted and/or cabled together and heat set, and the bulk of the high bulk yarn is at least 12 cm³/gm.

18. The high bulk yarn according to claim 17, wherein the filaments are singlecomponent filaments.

19. The high bulk yarn according to claim 17 or claim 1 Shaving a weight of at least 1000 denier, preferably greater than 1500 denier and more preferably greater than 2000 denier.

20. The high bulk yarn according to any one of claims 17-19, wherein the high bulk yarn has a bulk of at least 14 cm³/gm or at least 16 cm³/gm.

21. The high bulk yarn according to any one of claims 17-20, wherein the polymer includes at least one of a polyethylene terephthalate (PET) and a polybutylene terephthalate (PBT).

22. The high bulk yarn according to any one of claims 17-21 , wherein a weight of the filaments is greater than 2 dpf, or greater than 3 dpf or greater than 4 dpf.

23. A floor covering material comprising: a base backing; and a pile comprising the high bulk yarn according to any one of claims 16-22. The floor covering material according to claim 23 wherein, the high bulk yarn is tufted, knitted, knotted and/or woven to the base backing. The floor covering material according to claim 23 or 24 wherein, the high bulk yarn is cut to form a cut pile floor covering material.