A method for making a multifilament polyolefin yarn as a continuous process on a single melt-spin-drawwind machine and the multifilament polyolefin yarn

Abstract

Invention discloses a method for making polyolefin multifilament yarn mimicking natural wool on a single melt-draw-spin machine and a multifilament yarn / fiber mimicking natural wool. The key steps of the method include said feeding the raw material into an extruder to convert them into a fluid melt, passing the said fluid melt through spinneret, where the polymer comes out in form of continuous filaments, cooling the filaments through a blast of cross-flow cold air whereby plurality of filaments is bundled together to form a multifilament yarn, applying spin finish via a nozzle to impart further processability of yarn, heating and stretching the said spin finished yarn through a series of godet rolls wherein multifilament yarns are slightly fused as per requirement in controlled / random distribution to create a loose web like structure. The yarn has random binding / fusing and slight wave and a yarn to metal coefficient of friction between 0.20 to 0.30.

Description

[0001] A METHOD FOR MAKING A MULTIFILAMENT POLYOLEFIN YARN AS A CONTINUOUS PROCESS ON A SINGLE MELT-SPIN-DRAW-WIND MACHINE AND THE MULTIFILAMENT POLYOLEFIN YARN

[0002] FIELD OF INVENTION:

[0003] The present invention relates to a method for making a polyolefin multifilament yarn mimicking natural wool and a multifilament yarn / fiber mimicking natural wool made therefrom. The present invention particularly relates to a method of making a polyolefin multifilament yarn that mimics natural wool and a natural wool mimic yarn / fiber made therefrom in on single melt spin draw wind machine.

[0004] BACKGROUND:

[0005] Today the cultivable land area has been reducing tremendously thereby resulting in lower crop of grown cotton / jute etc. Moreover, there has been stagnation in or even falling livestock population. Accordingly, the world population of livestock like sheep / lamb / goat etc have nearly stagnated and coupled with hotter climate there is a lower useable fiber yield from such animals (refer to Table 1 and Figures 3 and 4). India has the second largest sheep population in the world, therefore the impact of lower yield is serious. Further, natural fibers of plant and animal origin like wool / cotton / jute etc. are becoming scarce and expensive as climate change is causing reduced yield of usable such material. Therefore, a limited availability of natural fibers and the inherent drawback in natural fibres have led to the development of man-made fibers, which are a viable alternative to the natural fibers.

[0006] In addition, there are growing concerns of environmental pollution as unstructured processing of fibers from natural origin like wool / cotton etc. result in discharge of effluents which are not treated properly and hence lead to pollution. For example, Wool processing requires scouring & dyeing with chemicals to remove unwanted fractions / foreign material. The effluents are not treated properly resulting in pollution of precious natural resources and ground water pollution. According to the 17th Livestock Census (2019), India had a total of 74.26 million sheep, marking a 14.13 percent increase from the previous census in 2012. The states of Telangana, Andhra Pradesh, Karnataka, and Rajasthan account for the majority of this population. However, the Department of Animal Husbandry and Dairying (DAHD) Annual Report 2024-25 (see Table 1) highlights a contrasting trend in wool production.

[0007] Table 1: Indian Wool Production from (from Annual report of Department of Animal Husbandry (DAHD) 2024-2025)

[0008] Year Million Kg

[0009] 2016-2017 43.5

[0010] 2017-2018 41.46

[0011] 2018-2019 40.42

[0012] 2019-2020 39.46

[0013] 2020-2021 36.93

[0014] 2021-2022 33.13

[0015] 2022-2023 33.6

[0016] Negative Growth Rate of CAGR

[0017] wool from Sheep in - 3.58%

[0018] India

[0019]

[0020] From 2018-19 to 2023-24, wool production declined at a Compound Annual Growth Rate (CAGR) of -3.58 percent, reaching just 33.69 million kilograms in 2023-24. reflecting changing dynamics in India's traditional wool-producing regions. Main reasons are attributed to:

[0021] ♦♦♦ the diminishing pastoral land as alternate land use is found and developmental projects are given priority over pastoral stretches.

[0022] ♦♦♦ changing climate with floods and droughts wiping out pastoral land, fodder and feed for the sheep

[0023] ♦♦♦ Higher Temperature extremes causing quality and quantity of wool to decline sharply ♦♦♦ Poor quality of Indian Wool (short fibers / rough texture ) leading to less remuneration for sheep herders.

[0024] ♦♦♦ Change of end use of sheep from Wool to Meat. While population of sheep has grown to over 70 million, the production of wool has come down year on year

[0025] DRAWBACKS IN CURRENTLY AVAILABLE PRODUCTS:

[0026] Currently available polypropylene multifilament yarns, made as substitutes for coarse count natural fibers, have the drawback of having very high stiffness when they are manufactured in heavier deniers-and hence they are not particularly suitable for making alternative textiles to those made using natural fibers in coarser counts, for example coarser applications like floorings and furnishings, carpets and rugs etc., where predominantly the coarse count of wool / cotton / other natural fibers are being used. The growing human population has greater requirement for and varied uses of fabrics and textiles and the naturally available fibers are not sufficient to meet the need.

[0027] Moreover, the currently available multifilament polypropylene (PP) yarns are undesirably artificial in look and plasticky in feel. They are either very smooth and slippery, or are very hard, rough and shiny. For example, in one of the applications of rugs & carpets, the currently available PP multifilament yams are not suitable for applications such as tufted carpets as they are too slippery and the trimmer cannot cut the tuft uniformly due to yarn slippage (like having a very jagged hair cut). On the other hand, the hard rough and shiny feel and look is not appreciated as it gives a very plasticky look and feel.

[0028] Similarly, there are a lot of applications in floorings and furnishings that require the use of substitute of natural fibers in heavy count / denier. The principal requirement of such applications is that the substitute yarn should look and feel like natural fiber. The industry has been able to provide very soft yams in very fine deniers / fine counts for clothing applications in select polymers but they have not yet developed yams in coarser counts / denier that mimic natural fibers in look and feel.

[0029] CN115161832B discloses a method for preparing a high-strength yam with a hairy / woolly feel in (5 tex to 200 tex) 55 denier to 2200 denier by first pretwisting the filaments and then performing secondary twisting and abrasion treatment on the pre-twisted filaments at the same time. However, twisting is not only an additional process and resource intensive, but it also compacts the yam thereby resulting in poor quality of woolly feel. CN115161832B tries to achieve a spun yam type feel by abrasion which in itself is damaging the yarn surface. Moreover, the kind of yarn prepared by the said method disclosed in this patent is not found suitable for upholstery and furnishings as the hair needs to be removed from the surface. Further, the physical abrasion of filament or yarn leads to tensile strength loss & may produce fabric surface with protruded filaments which may or may not be desirable. Also, this prior art uses multiple operation stages & machine involving major manpower & capital intensive. Hence there is a need to develop a single machine operation method to produce yarn which provides the high quality of properties of colour, lustre^ look and feel like natural fiber and overcome the undesirable properties of natural fibres, such as water or moisture absorbance, low resistance to acid and alkalis, stainability, subject to pest attacks, fungal and bacterial growth etc.

[0030] It should also be noted that the existing processes of making yarn trying to mimic yarn of natural origin are generally made on multiple lines, using multiple process like texturing, twisting and many others or their combination. For example in the first machine a partially oriented yam (POY) is wound on a roller / winder which is then taken to another machine where the drawing / texturing process is carried out.

[0031] Referring to Figure 6, the conventional melt-spin-draw wind machine on which the inventive processes are carried out on single machine. THE OBJECTS OF THE INVENTION:

[0032] The objective of the present invention is to provide a method for making a polyolefin multifilament yam mimicking natural wool like yarn feel in coarse counts on single machine in single process

[0033] Yet another object of the present invention is to provide a polyolefin multifilament yam mimicking natural wool like yarns / fibres that incorporate the high quality of properties of colour, lustre, soft look and feel like natural fiber and overcome the undesirable properties of natural fibres.

[0034] The mimic wool olefin yams are made in heavier denier / coarser counts like denier over2000 with 8 to60 denier per filament (dpf) corresponding to filament thickness of over 40 microns which is similar to the carpet wool fiber (Refer Table 2 for yam denier to micron conversion)

[0035] SUMMARY OF THE INVENTION:

[0036] The present invention relates to a method or process of making a polyolefin multifilament yam mimicking natural wool yam on a single melt-spin-draw winding machine. The said process comprises the following steps (see Figure 1):

[0037] 1. Feeding the granules of polyolefins and material recipe into an extruder wherein the extruder has a heating chamber and a screw / barrel arrangement and where the granules are heated and moved forward under pressure to convert them into a fluid melt, 2. Passing the said fluid melt through spinneret, which is a shower type die, where the polymer comes out in form of continuous filaments, 3. Cooling the filaments through a blast of cross- flow cold air to make the melt solid and suitable for a continuous yarn formation wherein plurality of filaments is bundled together to form a multifilament yam, 4. Applying spin finish via a nozzle to impart further processability of yarn

[0038] 5. Heating and stretching the said spin finished yarn through a series of godet rolls wherein multifilament yams are slightly fused as per requirement in controlled / random distribution to create a loose wavy web like structure and wherein the heating can be done by heated godets and stretching is done by changing the speed of the godet system,

[0039] 6. Finally winding such processed multifilament yam polyolefin yarns mimicking natural wool like yarn on bobbins for end use applications.

[0040] The process disclosed herein has been carried out on a single melt spin draw winding machine to make the yarn disclosed herein.

[0041] LIST OF FIGURES:

[0042] Figure 1 shows a flow diagram of the process of the invention

[0043] Figure 2a shows the conventional yarn with parallel strands

[0044] Figure 2b shows the yarn of the invention

[0045] Figure 3 shows wool production in India over a period between 2012 and 2023 Figure 4 shows number of sheep in India over a period between 2018 and 2023 Figure 5 shows comparison of coefficient of friction for different types of wool and the Inventive Olefin Mimic Wool yarn

[0046] Figure 6 shows a conventional melt-spin-draw apparatus for inventive process

[0047] DETAILED DESCRIPTION OF THE INVENTION:

[0048] Figure 1 of the accompanying drawing illustrates various steps of the process of the present invention in flow diagram. As per the flow diagram in Figure 1, the melt spin draw winding process comprises of the following steps.

[0049] Raw material comprising polymeric material fed via a hopper into the Extrusion system (2) comprising screw -barrel- die system and extruding it under heat and pressure to form fine filaments. These filaments are unstable and need to be cooled via the Quench Cooling process (3) where cross flow air controlled for temperature and flow is fed perpendicular to the spin line (90 degrees) to the filament spin line (in this case air is fed horizontally as the filament is extruded vertically). Further the quenched yam is subjected to a Spin Finish Application (4) and Stretching (5), following which the finished mimic wool yarn is wound on spools.

[0050] The invention discloses a judicious blend of the process parameters and ingredients to arrive at the desired waviness of the filaments in yarn, random fusing both visually determined imparting tactile hardness / softness and hand / feel character of the yam, mainly decided by yam to metal friction co-efficient value.

[0051] A detailed description of various parameters of the present novel and inventive process / method is given below.

[0052] Step 1: Selecting proper raw materials:

[0053] a) Polyolefin: 80% to 98% of total raw material mixture w / w basis are polyolefin polymers which can be homopolymers , copolymers and / or reprocessed polyolefin polymer (RPP) or a blend of the same. RPP content maybe upto 50% of total raw material mixture w / w basis Any commercially available knownpolyolefine polymers are used preferably polypropylene used. In particular, Polyolefin polymer with Melt Flow Index (MFI) in the range of MFI between 8 and 35 are used to achieve varied level of hand feel in the yarn. In the present invention, we have used materials with different MFI and have been able to achieve similar desired results. The materials used were from different manufacturers viz Indian Oil Corporation ltd (IOCL), Hindustan Mittal Energy Limited (HMEL) and ONGC Polymers Addition Limited (OPAL). All three are reputed manufacturers of Olefin polymers. In addition, polymers have been used from Haldia Petrochemicals limited and Reliance Industries Limited. The preferred polymer range is from 8MFI to 20 MFI

[0054] b) Additives: PP / PE based hindered amine light stabilizers (HALS) type UV agent in granules form are added as additive in the range of 0% to 12%w / w for providing UV protection for outdoor use. In specific HALS 20 type UV protection agents in PP polymeric base as supplied by Manufacturers have been used to the extent of 4% by weight of base polymer.

[0055] c) Colour Additives: PP / PE based colour and Masterbatch are added as per requirement between 0% to 15% w / w for imparting colour and delustering agent as per requirement of the end use.

[0056] d) Spin finish oil: A spin finish oil comprising of fatty acid esters and antistat additives in water-based solvent is used here to give an ultimate oil pickup between 1% - 4% w / w on the yarn (applied in step 4).

[0057] Step 2. Extrusion:

[0058] In polymer extrusion, the raw material is gravity fed into the feed throat of the extruder where a rotating screw pushes the material. The screw is housed in a barrel which is heated. The heating temperature of the barrel is largely dependent of the Melt flow characteristic of the polymer. Heat is generally provided in multiple zones over the length of the barrel. The temperatures are set on the basis of the melt characteristics of the polymer. For example, in the inventive yarn a polyolefin polymer with MFI of 13 has been processed on a extruder with multiple heating zones, present machine had three zones in the extruder followed by a melt delivery pump and a die housing the spinneret. When processed in the machine with three zone heating in extruder followed by a melt pump and die, the temperature ranges are in the area range of 180 to 210°C in zone one going up to 240 °C in the second zone and in third zone of the barrel with temperature going up to the 270°C and up to 280 °C in the melt pump and die housing the spinnerets. The temperatures are so maintained that the raw material in solid granular form is changed into a melt which can be extruded through spinneret. The pressure of the melt is developed due the screw profile and the pressure is maintained in the range of 25 bar to 90 bar.

[0059] Step 3. Quench Cooling: In man-made filament yarn from polymer, the processing quench temperature plays a very critical role in changing the morphology of the extruded yam. Sudden cooling results in development of crystals which is not suitable for certain applications whereas inadequate cooling results in yarn with undesirable properties such as very high elongation and residual shrinkage. In general, for melt spun polymers, the process of quenching is achieved by either purging the melt in cold water or by passing cold air from behind or around the filaments to cool them. The process of Melt spin draw winding of Multifilament yarn is generally having an air-cooled quench system where cooled air is blown at a controlled speed from behind the filaments. The rate of cooling is dependent on the contact temperature and time of the air with the continuously moving filament. As the filament drops down from the spinnerette, it is encountered by a cross flow of cold air. This cools the molten filament into a solid form. The temperature of cool air is maintained between 5 and 20 °C . However, in the present invention the quench temperature range is kept in the range of 10 to 20 °C for quench air. A quench temperature in the range of 12 to 15 °C has been found to be more suitable. A cross-air quench flow rate of 0.7 m / s -1.8 m / s is generally used. In the present invention, the quench flow rate is maintained between 0.85 and 1.2 m / s.

[0060] Step 4: Applying Spin Finish: In the present invention a spin finish oil as is commonly available for processing of multi filament yarns, comprising of fatty acid esters and process aid additives is used. Spin finish helps in further processing of yams over the godets. The spin finish changes the contact behaviour between the yam and the godet surface. The composition of spin finish and the quantity determine the heat transfer rate, grip / slip over godet (abrasion or lack thereof), uniformity of stretch, discharge of static electricity etc. If spin finish is not applied uniformly then the filaments will have different uptake of temperature and will also have different slip on the godets. There will be a vast difference in the denier, elongation, strength etc in the yam. Spin finish can be applied by passing the yam over rollers as in lick roll type of spin finish application or by passing the yam through spin finish applicator nozzles which are v shaped guides with holes from which spin finish is pushed through. However, we find that the v shaped ceramic guide-based system is better than the lick roll system. Spin finish is applied by passing the yam over two v shaped ceramic guides having a hole in the back side through which the spin finish oil is delivered. These Ceramic guides are in line of yam extrusion and are placed opposite each other to ensure uniform application of spin finish to all filaments. The quantity of spin finish oil being pushed through the hole is controlled by means of spin finish metering pump driven by a motor controlled by an inverter drive enabling precise output control. This spin finish is as a ratio of the output of yam from the extruder. General spin finish between 1% to 20% w / w can be used in neat or diluted form. However, in the present invention, spin finish in the range of 2% to 6% in neat as well as in mixture blended with water is preferable. The uniformity of application of spin finish and the quantity of spin finish determines the unique formation of weblike structure & the uniformity of the final yam properties in each of the multiple filaments.

[0061] Step 5: Stretching with different parameters of temperature and speed. Yam fresh after extrusion, quench cooling and spin finish application (of step 2, followed by step3 and 4) has very low / no polymer orientation. The yam needs to be further processed by heating and stretching to align the polymer molecules in the direction of the length of the yarn. This alignment helps to develop technical properties of the yam such as strength, elongation and shrinkage etc. The passing of yam over rotating heated rollers (godets), changes the temperature of the yam and the differential speed between the godet changes the diameter of the yarn in the case of stretch / relaxation. The temperature and speed of these rotating rollers is controlled through invertors drives and microprocessor-based controls for ease of fine settings. The process of stretching also causes a change in the diameter (resulting in the change of denier) of the yarn. The process of stretching over heated rolls provides dual purpose of heat and stretch at the same time which facilitates the stretching as the yarn becomes more pliable, allowing the molecules to realign and also the diameter changes due to the stretch (change in denier). The speeds of the godets are progressively increased / reduced to provide a stretch / relaxation to the yam passing over these godets. Common stretch ratios for PP multifilament yams are between 4 to 12. However, to obtain the mimicked wool like multifilament yams of the present invention, the stretch ratio is kept below the common stretch ranges between 2 and 6 by controlling the speed and temperature of the godets in the stretching zone.

[0062] As mentioned above, controlled heating and cooling is essential for producing high quality multifilament polyolefin yams mimicking natural wool like yarn of the present invention. The temperature range for heating the yams is set so that the yam over godet contact does not cross the melting point of the polymer. To provide the slight fusing, yarn is heated just around the softening temperature and thereafter the heat of stretching, fuses the yam in random spots. In the inventive process, godet temperature and speed settings for godet rolls are in the range of unheated feed roll at 250 to 1250 mpm followed by first godet at 75 to 95 °C and first godet roll delivering a yam speed of 260 to 1260 mpm and further progressing up to 90 to 120°C on subsequent rolls going up to 135 degrees for intermediate roll at 520 to 1520 meters per minute (mpm) and the maximum speed of 580 to 1580 meters per minute with roll temperature of 110 to 160 °C and thereafter cooling and relaxation temperature of 100 °C at speed of 565 to 1565 meters per minute to a final winding speed of 570 to 1570 meters per minute, giving a stretch ratio of approx. 2 to 6. Depending on the melt spin draw wind machine configuration multiple drawing zone may vary from 2 to 7 steps / stages. Hence the godet speed and contact temperatures are so adjusted and controlled so as to be able to achieve a physical change in the yarn processed to obtain the desired technical characteristics comprising strength, elongation, the waviness in yarn and fusing in random places which mimics wool (wool fibre has a natural waviness and the individual fibers of wool are entangled with each other due to the scales on the outer surface of the wool fiber) such that resultant yarn to metal friction co-efficient is near to natural wool, i.e. 0.2 to 0.3. It is important to note that some properties of the yam disclosed herein, such as coeffient of friction is an important indicator of the tactile feel of the yarn itself and a fabric made from it. Figure 5 (and Table 4) shows coefficient of friction of said inventive olefin mimic wool yarn and the predominant natural wool yarns from New Zealand and India.

[0063] • Yam friction generally refers to the resistance encountered when a yarn is either rubbed against itself or touched by fingers. This resistance plays a key role in how a yarn feels to the touch, making it an important factor in assessing tactile perception.

[0064] • Measuring the surface friction of yarn provides valuable insights into their physical properties, which influence both comfort and usability. In clothing, friction affects the fabric's handle and overall comfort. In technical and industrial applications, it determines how well a fabric performs under various conditions.

[0065] One can quantify tactile perception by measuring the surface friction. The tactile feel of the fabric is largely dependent on the frictional characteristic of the constituent yarn and the weave pattern.

[0066] The frictional characteristics of yarn is a key factor in determining the smoothness of textiles. It is also impacts the light refl ection / ab sorption ability of the yarn which in turn determines visual look of the fabric. These factors are used for the selection of the appropriate yarn in different technical and clothing productions.

[0067] Further it is important for mimicking the natural wool that polyolefin inventive filament size should be like natural wool.

[0068] Wool classification and grading

[0069] As seen below in the wool classification and grading data (see Tables 2 and 3), yarn suitable for carpet and upholstery use is generally above 45 microns corresponding to denier ranges >5000

[0070] Wool Classification: Table 2 Based on Diameter , Merino Wool is graded as follows

[0071] <15.5 Microns Ultra Fine Wool

[0072] 15.6 - 18.5 Microns Super Fine

[0073] 18.6- 20 microns Fine

[0074] 20.1 to 23 microns median

[0075] >23 Microns Strong

[0076] Based on Diameter - Cross bred Wool is graded as follows

[0077] 27- 31 Microns Fine Cross Breed

[0078] 32- 35 Microns Median Cross Breed

[0079] >36 Microns Coarse Cross Breed

[0080] 35- 45 Microns Carpet Wool

[0081]

[0082] Any wool finer than 25 microns can be used for Garments, while coarse grade wool are used for outer wear , rugs , blankets etc .

[0083] Composition of Multifilament Yarns: Table 3

[0084] Denier to Micron Denier Filaments DPF Diameter in Conversion Table Microns of each filament Micro Denier 24 48 0.50 8.31

[0085] 48 48 1.00 12.87 Lower and Finer Denier 75 48 1.56 16.08

[0086] 150 48 3.13 22.74 400 98 4.08 25.99 1200 98 12.24 45.95 5000 392 12.76 46 Coarse Denier 8000 392 20.41 58.12

[0087] 10000 392 25.51 64.996 12000 392 30.61 71.19 14000 392 35.71 76.89

[0088]

[0089] 16000 392 40.82 82.20 In Table 3:

[0090] Denier (D): A direct system — lower denier means finer yam.

[0091] Count (Ne): An indirect system — higher Ne means finer yam.

[0092] Filament Count: More filaments in a yam bundle generally mean a softer and more flexible yarn, even at higher deniers.

[0093] Denier per Filament (dpf): A useful metric for comparing softness and fineness. For example, 24D / 48f =.56 dpf (fine), while 300D / 96f = -3.13 dpf (coarse).

[0094] By controlling the process parameters of quenching, spin finish, contact time and temperature during stretch the applicant of the present invention has been able to provide random binding / fusing and slight wave at the same time maintaining a level of surface feel that mimics polyolefin multifilament yarn to natural wool like yarn of the present invention which is available as a continuous filament yarn.

[0095] It is evident from the foregoing that the invention has the following embodiments.

[0096] The principal embodiment discloses a method for making a multifilament polyolefin yarn mimicking wool like yarn, said method comprising the following steps:

[0097] a. selecting raw materials including polyolefin blend, UV agent additives, colour additives, and spin finish oil;

[0098] b. extruding the raw materials through an extruder having a rotating screw inside a barrel, a melt pump and a die housing a set of spinnerets, wherein said raw materials pass through said extruder under predetermined temperature and pressure to produce extruded yarn;

[0099] c. quench cooling the extruded yam using blown air of a temperature between 5 and 20 °C and at a cross-air flow rate of 0.7 to 1.1 m / s;

[0100] d. applying spin finish to the quenched yam;

[0101] e. stretching the spin finished yam over a set of rotating heated godets.

[0102] Another embodiment discloses a method as disclosed in the principal embodiment wherein said raw materials comprise polyolefin granules blend in an amount of 80% to 98% w / w which may content blend of virgin polyolefin 30 to 95% and RPP 0 to 50% and Copolymer 0 to 20%; PP / PE based hindered amine light stabilizers in an amount between 0% to 12%, and colour additives in an amount of 0% to 15% w / w, and fatty acid esters and antistat additives in water based solvent in an amount of 1% to 2% w / w basis.

[0103] A further embodiment discloses a method as disclosed in the previous embodiment wherein said polyolefins are in the preferably in form of homopolymers with a melt flow index between 8 and 35, wherein homopolymers / copolymer of different melt flow indexes may be blended to get desired MFI value.

[0104] Yet another embodiment discloses a method as disclosed in the principal embodiment wherein heat is generally provided in multiple zones provided over the length of the barrel, and wherein the temperatures are in the area range of 210°C in zone one, going up to 240 °C in second zone and in the third zone of the barrel, going up to the 250 °C and up to 270 °C in the melt pump and the said die housing the spinnerets, and wherein the pressure of the melt within the barrel is maintained in the range of 25 bar to 90bar.

[0105] Another embodiment discloses a method as disclosed in the principal embodiment wherein the temperature of the blown air is maintained between 10 to 20 °C with the blown air being released at a cross-air flow rate of 0.85 and 0.95 m / s.

[0106] A further embodiment discloses a method as disclosed in the principal embodiment wherein said spin finish is applied uniformly by passing the yarn over rollers, said roller being of the lick roll type.

[0107] Yet another embodiment discloses a method as disclosed in the principal embodiment wherein said spin finish is applied by passing the yarn through two v shaped ceramic guides having a hole in the back side through which the spin finish oil is delivered, and wherein said ceramic guides are in line of yarn extrusion and are placed opposite each other.

[0108] Another embodiment discloses a method as disclosed in the principal embodiment wherein the amount of spin finish oil is in the range of 1% to 6% w / w in neat form as well as in mixture form blended with water.

[0109] Another embodiment discloses a method as disclosed in the principal embodiment wherein the stretch ratio is in the range of 2 to 6.

[0110] Another embodiment discloses a method as disclosed in the principal embodiment wherein the temperature and speed settings for godet rolls are in the range of unheated feed roll at 150 to 1250 mpm followed by first godet at 75 to 95 °C and first godet roll delivering a yam speed of 160 to 1260 mpm and further progressing up to 90 to 120 °C on subsequent rolls going up to 135°C for intermediate roll at 320 to 1520 meters per minute (mpm) and the maximum speed of 380 to 1580 meters per minute with roll temperature of 110 to 160 °C and thereafter cooling and relaxation temperature up to 100 °C at speed of 465 to 1565 meters per minute to a final winding speed of 470 to 1570 meters per minute, giving a stretch ratio of approx. 2 to 6.

[0111] Another embodiment of the invention discloses a polyolefin yarn mimicking wool like yam, said yarn having random binding / fusing and slight wave at the same time maintaining a level of surface feel that mimics polyolefin multifilament yam to natural wool like yarn.

[0112] Another embodiment discloses a method as disclosed in the previous embodiment wherein the yarn has a yarn to metal coefficient of friction between 0.20 to 0.30. Table 4: Coefficient of Friction (COF) values of Olefin Mimic Wool Yarn , New Zealand Wool and Indian Wool

[0113] Yarn Type New Zealand Indian Wool Inventive Olefin Wool Mimic wool

[0114] 1 0.24 0.25 0.3

[0115] 2 0.24 0.28 0.26

[0116] 3 0.22 0.3 0.31

[0117] 4 0.23 0.31 0.22

[0118] 5 0.2 0.27 0.2

[0119] 6 0.21 0.29 0.2

[0120] 7 0.22 0.25 0.18

[0121] 8 0.23 0.27 0.2

[0122]

[0123] It should be noted that any fabric made from such inventive fibers may be, without limitation, tufted, woven, knit, non-woven, in-laid scrim, any combination thereof, and the like. Additionally, such fabrics may include yams and fibers other than the inventive olefin / polypropylene yarns / fibers, including, without limitation, natural fibers, such as cotton, wool, abaca, hemp, ramie, and the like; synthetic fibers, such as polyesters, polyamides, polyaramids, other polyolefins (including non-low-shrink polypropylene), polylactic acids, and the like; inorganic fibers such as glass, boron-containing fibers, and the like; and any blends thereof.

[0124] The yarn of the invention is now explained using the following examples.

[0125] Example 1: Olefin Melt spin draw winding example for Mimic Wool yarn Inventive

[0126] In this Example according to the melt spin draw winding process, Inventive Olefin yarns are made with raw material (step 1 of the process of invention as described in the foregoing sections) comprising 70% Polypropylene Homopolymer, 25% RPP, 1% copolymer, 4.0% of Additive MB for UV Stabilization. The raw material such processed in Extrusion system maintaining a melt pressure between 25-35 bar (step 2 of the process of invention as described in the foregoing sections) and extruded Multifilament Olefin Yam is subject to Quench Cooling (step 3 of the process of invention as described in the foregoing sections) cooled in a quench chamber with Cross flow air system having an air temperature of 12 °C and a flow rate of 0.85 - 0.95 m / s. Each bundle of Olefin Multifilament Yam is subject to Spin Finish application (step 4 of the process of invention as described in the foregoing sections) by passing over two oil flow nozzles fed by a metered oil delivery device. The oil pump delivers around 2% oil on yam w / w basis. Further the as such extruded Olefin Multifilament Yam is received on a take up roll which is rotating at a yarn delivery speed of 300 mpm (meters per minute). At this stage 4 such bundles of yarn are collated together is subject to drawing and further stretching. The Multifilament Olefin Yarn is then subjected to unidirectional stretching zone (step 5 of the process of invention as described in the foregoing sections) by entering into the first set of godet and separator roll. The 1st godet maintained at a temperature of 85 °C and a rotation speed to give a yarn delivery speed of 310 mpm. This is followed by yam moving on to the second set of godet and separator rolls where the speed is maintained at 370 mpm and the temperature is 115 °C . The yam then moves to the third set of godet rotating to give a yam delivery speed of 420 mpm and a temperature of 125 °C . The yarn then moves on to the fourth set of godet at yarn delivery speed of 490 mpm and temperature of 140 °C . To give mild annealing the yam is further transported to the next set of godet operating at speed of between 520 and 550 mpm more so at speed of 530 mpm maintaining a godet surface temperature of 120 °C . The yarn then enters a sixth set of godet rotating at a yam delivery speed of 510 mpm .The yam so produced is wound in cross wound in winding device at a speed of 520 mpm (step 6 of the process of invention).

[0127] The Multifilament Olefin Yarn disclosed in the foregoing example which has been obtained using the process disclosed herein has the following properties:

[0128] Denier - 12000

[0129] DPF 30

[0130] Average filament Thickness: 0.076 mm ( 76 micron)

[0131] Breaking tenacity: 2.0 - 2.5 g / denier

[0132] Elongation at break: 36% Appearance: - Wavy yarn with randomly bound web of filament Intermediary random bind: 20 -30 per meter.

[0133] Example 2: In yet another instance experiment to process mimic wool yarn inventive are made with raw material (step 1 of the process of invention as described in the foregoing sections) comprising 96 % Polypropylene Homopolymer, 4.0 % of Additive MB for UV Stabilization. The raw material such processed in Extrusion system maintaining a melt pressure between 65-70 bar (step 2 of the process of invention as described in the foregoing sections) and extruded Multifilament Olefin Yarn is subject to Quench Cooling (step 3 of the process of invention as described in the foregoing sections) cooled in a quench chamber with Cross flow air system having an air temperature of 12 °C and a flow rate of 0.85-0.95 m / s. Each bundle of Olefin Multifilament Yarn is subject to Spin Finish application (step 4 of the process of invention as described in the foregoing sections) by passing over two oil flow nozzles fed by a metered oil delivery device. The oil pump delivers aaround 2.5% oil on yam w / w basis. Further the as such extruded Olefin Multifilament Yarn is received on a take up roll which is rotating at a yarn delivery speed of 500 mpm (meters per minute). At this stage 4 such bundles of yarn are collated together is subject to drawing and further stretching. The Multifilament Olefin Yam is then subjected to unidirectional stretching zone (step 5 of the process of invention as described in the foregoing sections) by entering into the first set of godet and separator roll. The 1st godet maintained at a temperature of 95 °C and a rotation speed to give a yarn delivery speed of 630 mpm. This is followed by yam moving on to the second set of godet and separator rolls where the speed is maintained at 1370 mpm and the temperature is 125 °C . The yarn then moves to the third set of godet rotating to give a yam delivery speed of 1420 mpm and a temperature of 145 °C . The yarn then moves on to the fourth set of godet at yam delivery speed of 1490 mpm and temperature of 135 °C . To give mild annealing the yam is further transported to the next set of godet operating at speed of between 1520 and 1550 mpm more so at speed of 1530 mpm maintaining a godet surface temperature of 120 °C. The yam then enters a sixth godet which is unheated and rotating to give a yarn speed of 1510 mpm

[0134] The yarn so produced is wound in cross wound in winding device at a speed of 1520 mpm (step 6 of the process of invention).

[0135] The Multifilament Olefin Yam obtained have the following properties:

[0136] Denier - 8000

[0137] DPF 20

[0138] Average filament Thickness: 0.058mm ( 58 microns)

[0139] Breaking tenacity: 1.8- 2.5 g / denier

[0140] Elongation at break: 30%

[0141] Appearance: - Wavy yarn with randomly bound web of filament Intermediary random bind: 25 - 40 per meter.

[0142] The foregoing examples are only illustrative and do not limit the full of the invention disclosed here.

[0143] Benefits of the present invention:

[0144] The following are some of the most important benefits which are accrued from the present invention:

[0145] a. The present invention provides, Continuous multifilament yarns, made from manmade material in a continuous process on a single melt-spin-draw winding machine, which have a feel like wool and which do not require further processing for use in textile applications like furnishing and carpets etc. The continuous multifilament yam is unlike wool which is Naturally sourced and processed hair of animals like sheep, camel etc. and which requires many stages of processing before the fiber can be used further for textile applications

[0146] b. The product of the present invention is a continuous filament form of large length of several kilometers and has colour and shine (dullness) like natural fibre albeit the colour and shine are more durable and environmentally friendly than dyed fibers of natural origin. It may be pertinent to note that process of dying / colouring of natural fibers is very resource intensive and if not manged well is highly polluting.

[0147] c. The yarns and fibers of the present invention can be used as made without further intermediate process and suitable replacement of other natural fibers like wool, cotton, jute, sisal etc

[0148] d. The product of the present invention is more durable that the wool / cotton and other natural fibers of plant and animal origin.

[0149] There are further benefits and advantages of the yam disclosed here using the method described here. These are evident from the Table 5 provided below:

[0150] Table 5: Benefits and advantages of the yarn of the invention

[0151]

Claims

Claims:

1. A method for making a multifilament polyolefin yarn mimicking wool like yarn characterised in that said method is a continuous process carried out on a single melt-spin-draw wind machine, said method comprising the following steps:a. selecting raw materials including polyolefine polymers, UV agent additives, colour additives, and spin finish oil;b. extruding the raw materials through an extruder having a rotating screw inside a barrel, a melt pump and a die housing a set of spinnerets, wherein said raw materials pass through said extruder under predetermined temperature and pressure to produce extruded yarn;c. quench cooling the extruded yam using blown air of a temperature between 5 °C and 20 °C and at a cross-air flow rate of 0.7 to 1.1 m / s; d. applying spin finish to the quenched yarn;e. stretching the spin finished yarn over a set of rotating heated godets.

2. The method as claimed in claim 1 wherein said raw materials comprise polyolefin granules in an amount of 80% to 98% w / w need base PP / PE based hindered amine light stabilizers in an amount between 0% to 12%, and need base colour additives in an amount of 0% to 15% w / w, and fatty acid esters and antistat additives in water based solvent in an amount of 1% to 2% w / w basis.

3. The method as claimed in claim 2 wherein said poly olefins are in the form of homopolymers / copolymers with a melt flow index between 8 and 35, wherein homopolymers of different melt flow indexes are used.

4. The method as claimed in claim 1 wherein heat is generally provided in multiple zones over the length of the barrel, and wherein the temperatures are in the area range 180 °C going up to the 270 °C and up to 280 °C in the meltpump and the said die housing the spinnerets , and wherein the pressure of the melt within the barrel is maintained in the range of 25 bar to 90 bar.

5. The method as claimed in claim 1 wherein the temperature of the blown air is maintained between 10 to 20°C with the blown air being released at a crossair flow rate of 0.85 and 0.95 m / s.

6. The method as claimed in claim 1 wherein said spin finish is applied uniformly by lick rollers.

7. The method as claimed in claim 1, wherein said spin finish is applied by passing the yam through two v shaped ceramic guides having a hole in the back side through which the spin finish oil is delivered, and wherein said ceramic guides are in line of yam extrusion and are placed opposite each other.

8. The method as claimed in claim 1, wherein the amount of spin finish oil is in the range of 1% to 6% w / w in neat form as well as in mixture form blended with water.

9. The method as claimed in claim 1 wherein the stretch ratio is between 2 to 6.

10. The method as claimed in claim 1, wherein godet temperature and speed settings for godet rolls are in the range of unheated feed roll at 150 to 1250 mpm followed by first godet at 75 to 95 °C and first godet roll delivering a yarn speed of 160 to 1260 mpm and further progressing up to 90 to 120 °C on subsequent rolls going up to 135°C for intermediate roll at 320 to 1520 meters per minute (mpm) and the maximum speed of 380 to 1580 meters per minute with roll temperature of 110 to 160 °C and thereafter cooling and relaxation temperature upto 100 °C at speed of 465 to 1565 meters per minuteto a final winding speed of 470 to 1570 meters per minute, giving a stretch ratio of approx. 2 to 6.

11. The method as claimed in claim 1, wherein 0% to 50% of total raw material mixture w / w is a blend of reprocessed polyolefin polymer.

12. A multifilament polyolefin yam mimicking wool like yarn, said yam having random binding / fusing and slight wave and maintaining a level of surface feel that mimics polyolefin multifilament yam to natural wool like yarn.

13. The multifilament yam as claimed in claim 12, wherein the yarn has a coefficient of friction between 0.20 to 0.30.

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