Patent Application
20250137173
The present disclosure generally relates to a method of manufacturing continuous filament yarn as a replacement of wool yarn for floor covering applications such as carpets and the like. The disclosure further relates to a wool-like yarn of continuous filament and to a floor covering manufactured from the yarn.
Conventionally wool has remained a most preferred fibre for making carpet yarns due to its natural bulk, softness, resiliency and thermal behaviour. It is also popular for its natural origin and hairy or woolly structure.
Lately wool has lost its most preferred status in the floorcovering industry due mainly to the following perceived disadvantages.
Additionally, the cost of wool is often considerably greater than synthetic alternatives, while their susceptibility to pests such as moths is well known.
To overcome the disadvantages of wool yarn in floorcovering application, bulked continuous filament (BCF) yarns made from polyester, polypropylene and nylon have gained popularity due to their continuous filament nature, that prevents linting, in addition to their reduced price. For these fibres, artificial bulk can be provided during the filament production process by texturizing the filaments e.g. by friction disc or stuffer box texturizing. They also exhibit good recyclability via mechanical or chemical recycling processes.
Nevertheless, the process of making BCF yarn for floorcovering application could never provide the feel and texture of products made from wool yarn due to the missing hairy look and feel of BCF yarn. Thus, a loop-pile floorcovering material produced from BCF or other textured continuous filaments was never able to provide the same natural hairy look and feel of products made from wool yarn.
Thus it would be desirable to produce a continuous filament yarn for floorcovering application, which could replace wool yarn by replicating its look, feel and hairiness with the additional advantage of being made from man-made fibre with low linting and good recyclability.
According to the invention, there is provided a method of manufacturing a wool-like yarn from continuous filaments of polymer material, wherein the yarn is obtained by a process comprising steps of: providing at least partially oriented, continuous filaments of the polymer; drawing and air texturizing the filaments to form threads, wherein a first group of straight filaments forms a core of the thread and a second group of filaments are overfed with respect to the first group of filaments to form a hairy sheath; and twisting and/or cabling a plurality of the threads together to form the wool-like yarn to have a weight of greater than 2000 dtex.
The resulting yarn exhibits a surprisingly similar look, feel and hairiness to that of wool yarn, while overcoming drawbacks of wool yarn such as linting, recyclability, UV resistance, antistatic properties and wear resistance.
Air texturizing of suitable polymer filaments has been shown to provide a useful degree of wooliness to the resulting yarn that exits the air texturizing process. For the purpose of the present invention, this yarn is referred to as a thread, to distinguish it from the subsequently assembled yarn of high dtex. It will nevertheless be understood that this is also a yarn, albeit of lower weight. As is otherwise conventional in air texturizing, air jets or the like cause the overfed filaments to entangle with one another to form a woolly or hairy envelope or sheath around the core. This sheath is sometimes referred to as the effect. Those filaments in the core that are not overfed are kept relatively straight and do not thus become entangled or are entangled to a lesser degree.
In the presently described process, the filaments may be initially provided in their partially oriented state. In consequence, they can be further drawn prior to the texturizing step. This can be used to remove nips or bonds between adjacent filaments or otherwise straighten them prior to the air texturizing process. They may be drawn to a fully oriented state or remain partially oriented in the final product. In preferred embodiments, the filaments have been drawn by at least 5% or at least 10% or at least 20% but less than 100%. It is also possible to use fully oriented yarns, since it is still possible to apply a limited amount of further drawing at the air texturizing stage, sufficient to break open any nips. It will be understood that fully drawn yarn may be drawn by more than 300%.
Twisting and/or cabling will take place in a subsequent step, which may take place at a different time and/or location to the air texturizing. In general, this will mean that the threads are wound to reels or bobbins. A number of reels will then be brought together for twisting. The reels may be provided with the same or different threads, e.g. of different colours. In the following, reference to twisting is intended to include cabling. In particular, in a first twisting step, a number of threads may be assembled together e.g. by light twisting to form a ply. In this context, twisting may also include air-twisting or false twisting, e.g. where alternate clockwise and anticlockwise twists are applied. Subsequently, a number of plies may be twisted or cabled together to form the wool-like yarn. By first assembling a number of threads together, high speed unwinding may be facilitated, whereby a cabling operation may proceed more quickly.
The filaments may be of any suitable weight according to the desired look and feel of the final product The filaments may all be of the same weight or some may be heavier than others. In an embodiment, heavier filaments may be provided in the sheath. Since certain air-texturising machines may be limited in the number of reels that can be combined, varying the weight of the respective filaments allows variation of the relative weights of the core and sheath. In an embodiment, the plurality of continuous filaments have a dtex per filament in a range from 0.5 dtex per filament to 10 dtex per filament. Preferably, these values line in a range of 4 to 6 dtex per filament, which has been found to provide a more stable process with less risk of filament breakage.
Furthermore, the at least partially oriented, continuous filaments may be provided from any suitable source of such filaments. In particular, they may be produced on site at the same location or may have been produced elsewhere. They may be produced by any conventional process, in particular by melt spinning and drawing. It is also possible that the at least partially oriented, continuous filaments are provided as bulk continuous filaments (BCF). In this case, the filaments are already texturised and may be fully oriented. Using BCF has certain advantages over non-texturised filaments. Firstly, since initial texturizing increases their bulk, BCF has a higher weight and it is easier to achieve the required overall dtex value for the wool-like yarn. This may be important where the air-texturizing machine is limited by the number of reels at the input side. It also means that fewer threads may need to be assembled or twisted and the air texturizing step may operate more effectively. Furthermore, use of textured BCF for the filaments in the core of the thread can increase their entanglement with and grip on the filaments of the sheath.
The filaments may also have any suitable cross-sectional shape. In certain embodiments, the partially oriented, continuous filaments are of a multilobal cross-sectional shape. This can further enhance the similarity with wool, since filaments of non-circular cross-section can have a less shiny appearance than those having a smooth cross-section. In an embodiment, octolobal filaments may be used.
The at least partially oriented, continuous filaments may be provided as a plurality of multi-filament tows. Each tow may be presented on its own reel or bobbin as provided at the end of an extrusion process. Such tows are commonly referred to in the art as partially oriented yarn (POY) and are referenced here as tows, merely for the purpose of distinguishing these loosely bundled filaments from the resulting heavy weight wool-like yarn as the outcome of the overall process. Preferably the tow is provided with nips to hold each tow together. The skilled person will be familiar with such processes that allow the filaments within a tow to be held together. This may take place by air entanglement or other equivalent procedures. Each tow may comprise from 10 to 500 filaments, preferably between 100 and 200 filaments. Furthermore. each tow may have a dtex in a range of from 100 dtex to 1500 dtex. preferably from around 500 dtex to 700 dtex. The weight of each tow will depend on the production machinery that delivers the continuous filaments and also on the nature of the air-texturising machine to be used. It will be understood, that the intention is to produce thread having a relatively high dtex value and that this can be achieved either by having high dtex tows or by combining a greater number of tows during the air-texturising process. Where this process is limited by the number of reels that can be combined. it is advantageous to use high dtex tows.
In an embodiment, the air texturising process is used to combine a number of such tows together, whereby a first tow forms a core of the thread and one or more further tows are overfed to form the hairy sheath. All of the tows may be identical or the tow or tows forming the core may be different from the tow or tows forming the sheath. As noted above, in cases where e.g. only two tows can be combined in an air texturizing machine, the tow forming the sheath may be of a higher dtex than the tow forming the core.
In an embodiment. drawing and air texturizing may takes place simultaneously in a continuous process. In this context, simultaneously is intended to mean that the tows are drawn prior to air texturizing in an inline process, without being subsequently wound to a bobbin. Drawing is particularly useful as a method of releasing the filaments in the tow for subsequent air texturizing. This can release any nip or connection between the filaments that might otherwise have impeded the air texturizing process. All of the filaments may be drawn to a fully oriented condition. Alternatively, only some of the filaments may be drawn and e.g. the filaments forming the core may be not further drawn and still nipped together. In an embodiment all of the filaments are drawn at a draw ratio of more than 1.3, preferably more than 1.5. Additionally, or in an alternative, the filaments of the sheath are drawn at a greater draw ratio than the core. In an embodiment, the filaments of the sheath are drawn at a ratio that is greater than that of the core to the same degree as they are overfed. This may result in a constant speed delivery of both groups of filaments.
The process of drawing and air texturizing may be performed in an otherwise conventional manner using conventional machinery. For polyester, drawing is preferably performed at a temperature around 180° C. The skilled person will be aware that this temperature may correspond to the normal temperature used during filament production for orienting the polymer. The filaments or tows may be subsequently cooled either before or during the air texturizing process.
During the air texturizing process, the degree of overfeeding may be determined according to the desired result. As the skilled person will understand, the degree of overfeeding will influence the volume of the sheath and hence the wooliness of the resulting thread. In an embodiment, the second group of filaments are overfed with respect to the first group of filaments by between 30% and 150%, preferably by around 80%.
The properties of the thread will also be influenced by the ratio of the number filaments in the core to the number of filaments in the sheath. In preferred embodiments, this ratio may be between 1:1 and 1:6, preferably around 1:2. For the case that the filaments in the core are distinct from those in the sheath, it is noted that it may be desirable that the ratio of the dtex of the core to the dtex in the sheath may also be between 1:1 and 1:6, preferably around 1:2.
Depending upon the weight of the filaments and the number of filaments combined to form each thread, the thread may have a dtex in a range of from 500 dtex to 5,000 dtex. In general, threads at the lower end of this range are too light for floor covering applications. As discussed above, a heavyweight yarn can be produced by assembling a number of threads together. Preferably, from 2 to 20 threads may be assembled together by twisting or cabling to form the wool-like yarn. The resulting yarn will thus have a weight of greater than 2000 dtex but more generally will have a weight of greater than 5000 dtex or even greater than 10 000 dtex or up to 50 000 dtex. Preferably, the threads have a weight of between 2000 dtex and 3000 dtex.
The yarn may be lightly twisted or highly twisted. In general, it will be twisted in a range of from 30 to 400 twists per meter (TPM). As noted above, the yarn may be assembled in a multi-step process, whereby in a first step, groups of threads are twisted together as a ply and in a further step, two or more plies are twisted or cabled together.
The process may also comprise heat setting of the twisted yarn, preferably in a temperature range between 85° C.-200° C. This is especially desirable for highly twisted yarn of more than 100 TPM or more than 200 TPM in order to better maintain the twist during subsequent processing and use of the yarns and the subsequently manufactured floor covering. Heat setting preferably takes place at a temperature that is below the drawing temperature preferably in a temperature range between 85° C.-110° C.
The polymer material used to manufacture the continuous filaments may be any suitable polymer having the required properties for its use as a component in a floor covering. Typically, it may be selected from the group consisting of polyesters, polyamides, polypropylene and copolymers thereof. The invention is particularly applicable to polyesters including PET and PBT.
The invention also relates to a wool-like yarn for the manufacture of floor coverings, the yarn comprising continuous filaments of polymer material assembled together to form threads with first straight filaments forming a core of the thread and second textured filaments forming a hairy sheath around the core and wherein a plurality of threads are twisted and/or cabled together to form a heavyweight yarn of greater than 2000 dtex. The yarn and its constituent threads and filaments may be as described above and hereinafter. In particular, the yarn may comprise filaments of the polymer combined with other fibres or filaments in a mixed yarn. The yarn may however alternatively consist essentially only of continuous filaments of a single polymer. In this sense, ‘consists essentially’ is intended to mean that the yarn is at least 99% or at least 95% of a single polymer filament. The remainder may be other fibres or filaments having particular functional purpose, such as anti-static conducting filaments, decorative or reflective filaments and the like.
Furthermore, the polymer of the wool-like yarn may include one or more masterbatches of additional materials mixed into the polymer. The masterbatches may be selected from the group consisting of: anti-microbial, anti-fungal, UV resistant, FR, stain resistant, anti-oxidant and pigment or any other of the conventional masterbatches that the skilled person would contemplate adding to such filament. Furthermore, the yarn may be subjected to any conventional dye processes, such as the use of disperse dye for polyester or acid dye for nylon. Additionally, space dyeing may be used to create a variegated colour such as by hank dyeing or by bobbin dying.
The invention also relates to a floor covering comprising the wool-like yarn described above or hereinafter. In preferred embodiments, the floor covering is a carpet or rug. The wool-like yarn may form an upstanding pile, which may be a cut-pile, a loop-pile, a shag-pile or the like.
The wool-like yarn may be tufted, knitted, knotted and/or woven into the floor covering. It may also form the backing of the floor covering or the backing may be formed separately of another material.
The features and advantages of the present disclosure will be appreciated upon reference to the following drawings of an of exemplary embodiment, in which:
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.
In a first step, according to
In a second step shown in
In a third step, shown in
In a fourth step, shown in
A yarn 9 as described above in relation to
The carpet was subjected to Hexapod testing. After 4000 cycles, the carpet exhibited a Hexapod rating of 4.5, which decreased to 4 after 8000 cycles and remained at 4 after 12000 cycles.
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
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2022/052877 | 3/29/2022 | WO |
