Method for producing a multifilament, multifilament produced from the method, and use of the multifilament

Abstract

The present invention relates to a method for producing a multifilament by melt spinning a composition containing a thermoplastic polyurethane, comprising: (a) passing the composition in a molten state through a spinneret to obtain an extruded filament; (b) passing the extruded filament through a set of godet rollers; and (c) winding the extruded filament of step (b) onto a bobbin via a winder at a winding speed of 2000-5000 m / min, wherein the thermoplastic polyurethane has a Shore hardness of 68D-90D measured according to DIN ISO 7619-1, as well as to the use of the multifilament of the present invention.

Description

[Technical field]

[0001] The present invention relates to a method for producing a filament. In particular, the present invention relates to a method for producing a multifilament from a composition containing a thermoplastic polyurethane (TPU), the multifilament produced from the method, and the use of the multifilament. [Background technology]

[0002] Rigid TPU multifilament, i.e. low elasticity and high modulus TPU multifilament, generally has large heat shrinkage.The as-spun rigid TPU multifilament produced usually has a high boiling water shrinkage (BWS) of more than 20% or even 30%.In turn, the article knitted by such multifilament shows large shrinkage during steaming / ironing, which causes the original size and hand feel of the article to deteriorate.

[0003] Furthermore, the current stiff TPU multifilaments produced have a high elongation at break, which requires special control over the filament tension in subsequent processing steps (even slight filament tension variations between skeins affect the filament uniformity and therefore cause defects in the final product).

[0004] WO 2020 / 169417 discloses a heat-setting method for reducing the heat shrinkage of TPU multifilaments produced by high-speed spinning, which can reduce the boiling water shrinkage of the multifilaments from 30% to less than 10%. The method relies on a heat-setting step for reducing the heat shrinkage of TPU multifilaments obtained by melt spinning, which requires additional equipment and operating time, resulting in higher production costs. Furthermore, heat-setting adversely affects the uniformity of the TPU filaments and causes the filaments to yellow during heat-setting, which is undesirable, especially for light-colored products.

[0005] In addition, the stiff TPU multifilaments produced in WO 2020 / 169417 have high elongation at break at relatively slow winding speeds. For example, the multifilaments produced in Experiment 1-1 of WO 2020 / 169417 show an elongation of 60%. As the winding speed decreases, the elongation at break becomes even higher. The high elongation at break makes the tension of the filament difficult to control in subsequent processing steps, such as winding, unwinding, twisting, knitting, and some other steps, where uniformity of tension along the skein is required. In turn, the variation in tension of the skein is the source of some defects in the resulting products, such as the multifilaments and knitted articles prepared therefrom.

[0006] Therefore, in order to simplify the manufacturing process and at the same time improve the quality of the product, there is a strong need to provide a method for producing a TPU multifilament having low heat shrinkage and low elongation at break by melt spinning a composition containing a thermoplastic polyurethane, during which the TPU multifilament is produced directly in the melt spinning stage without an additional heat setting stage, and the TPU multifilament produced therefrom has low heat shrinkage and low elongation at break, has improved filament properties such as good uniformity and low defect rate, and leads to improved article properties such as good dimensional stability, good hand feel and low defect rate of knitted articles made of the multifilament. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. 2020 / 169417 Summary of the Invention [Problem to be solved by the invention]

[0008] It is an object of the present invention to provide a method for melt spinning a composition comprising a thermoplastic polyurethane to produce multifilaments, which can directly produce multifilaments with low heat shrinkage, low elongation at break and improved filament properties without the need for additional processing steps such as a heat setting step.

[0009] Another object of the present invention is to provide a multifilament produced by the process of the present invention, which has low heat shrinkage, low elongation at break, and improved filament properties.

[0010] It is a further object of the present invention to provide the use of multifilaments in the manufacture of articles. [Means for solving the problem]

[0011] Surprisingly, it has been found that the above objectives can be achieved by the following embodiments: 1. A method for producing a multifilament by melt spinning a composition containing a thermoplastic polyurethane, comprising: (a) passing the molten composition through a spinneret to obtain extruded filaments; (b) passing the extruded filament through a set of godet rollers; (c) winding the extruded filament of step (b) onto a bobbin via a winding machine at a winding speed of 2000 to 5000 m / min, preferably 2000 to 4000 m / min, preferably 2100 to 2900 m / min, more preferably 2400 to 2900 m / min; wherein the thermoplastic polyurethane has a Shore hardness, measured according to DIN ISO 7619-1, in the range of 68D to 90D, preferably in the range of 70D to 90D, more preferably in the range of 75D to 88D, more preferably in the range of 81D to 87D, even more preferably in the range of 82D to 86D.

[0012] 2. the set of godet rollers of step (b) comprises a first godet roller operating at a speed of 1000-4000 m / min, preferably 1000-3000 m / min, more preferably 1100-2300 m / min, more preferably 1200-2100 m / min; The method of embodiment 1, wherein the first godet roller is preferably operated at a surface temperature of 30 to 120°C, preferably 50 to 100°C, more preferably 60 to 90°C.

[0013] 3. The set of godet rollers in step (b) comprises a first godet roller, a second godet roller, and a third godet roller arranged in series; the first godet roller operates at a speed of 1000-4000 m / min, preferably 1000-3000 m / min, more preferably 1100-2300 m / min, more preferably 1200-2100 m / min; the second godet roller operates at a speed of 2000-5000 m / min, preferably 2000-4000 m / min, more preferably 2500-3500 m / min, more preferably 2600-3200 m / min; and the third godet roller operates at a speed of 2000-5000 m / min, preferably 2000-4000 m / min, more preferably 2200-3200 m / min, more preferably 2400-3000 m / min; The method of embodiment 1 or 2, wherein the speed of the second godet roller is preferably faster than both the first godet roller and the third godet roller.

[0014] 4. The first godet roller operates at a surface temperature of 30-120°C, preferably 50-100°C, more preferably 60-90°C; the second godet roller operates at a surface temperature of 60-170°C, preferably 80-160°C, more preferably 90-130°C; the third godet roller operates at a surface temperature of 30-120° C., preferably 50-100° C., more preferably 60-90° C.; The method of embodiment 3, wherein the surface temperature of the second godet roller is preferably higher than that of both the first godet roller and the third godet roller.

[0015] 5. (a1) Before step (b), supplying the extruded filaments with spinning oil. 5. The method of any one of embodiments 1 to 4, further comprising:

[0016] 6. Thermoplastic polyurethane is (A) a polyol, (B) a diisocyanate, and (C) Chain extender wherein the polyol is selected from the group consisting of polyether polyols, polyester polyols, and any mixture thereof.

[0017] 7. A multifilament obtained by the method of any one of embodiments 1 to 6.

[0018] 8. The multifilament of embodiment 7, wherein the boiling water shrinkage of the multifilament according to ASTM D2259-02 is 18% or less, preferably 17% or less, more preferably 15% or less, even more preferably 13% or less, and even more preferably 10% or less.

[0019] 9. The multifilament of embodiment 7 or 8, wherein the elongation at break of the multifilament is less than 55%, such as less than 50%, such as less than 46%, such as less than 40%, at relatively slow take-up speeds of less than 3000 m / min, measured according to method A of ISO 2062:2009.

[0020] 10. The multifilament of any one of embodiments 7 to 9, which is a bicomponent or microtubular structure.

[0021] 11. Use of the multifilament of any one of embodiments 7 to 10 in the manufacture of clothing, shoes, or accessories, such as shoes, trousers, T-shirts, mesh chairs, watch bands, or hair bands.

[0022] The TPU multifilaments produced by the method of the present invention have improved filament properties such as low heat shrinkage and low elongation at break, good uniformity and low defect rate, leading to improved article properties such as good dimensional stability, good hand feel and low defect rate of articles made from the multifilaments, such as knitted articles made from the multifilaments, and the TPU multifilaments are produced directly by the method of the present invention without the need for an additional heat setting step. [Brief description of the drawings]

[0023] [Figure 1] FIG. 1 shows an example of an apparatus for melt spinning of TPU multifilaments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Unless otherwise defined, all technical and scientific terms used herein have the meaning commonly understood by one of ordinary skill in the art to which this invention belongs. As used herein, the following terms have the meanings set forth below unless otherwise specified.

[0025] The articles "a," "an," and "the" refer to one or more of the species designated by the term following the article.

[0026] In the context of this disclosure, any specific values ​​recited for a characteristic (including any specific values ​​recited in a range as endpoints) may be recombined to form a new range.

[0027] Further embodiments of the invention can be seen from the claims, the description and the examples. It will be understood that the features of the subject matter of the invention mentioned above and further described below can be used not only in the specific combinations shown but also in other combinations without departing from the scope of the invention.

[0028] Multifilament manufacturing method One aspect of the present invention is a method for producing a multifilament by melt spinning a composition containing a thermoplastic polyurethane, comprising the steps of: (a) passing the molten composition through a spinneret to obtain extruded filaments; (b) passing the extruded filament through a set of godet rollers; (c) winding the extruded filament of step (b) onto a bobbin via a winding machine at a winding speed of 2000 to 5000 m / min, preferably 2000 to 4000 m / min, preferably 2100 to 2900 m / min, more preferably 2400 to 2900 m / min; wherein the thermoplastic polyurethane has a Shore hardness, measured according to DIN ISO 7619-1, in the range of 68D to 90D, preferably in the range of 70D to 90D, more preferably in the range of 75D to 88D, more preferably in the range of 81D to 87D, even more preferably in the range of 82D to 86D.

[0029] The method of the present invention comprises the step (a) of passing a composition containing a molten thermoplastic polyurethane through a spinneret to obtain extruded filaments.

[0030] Step (a) of the method of the present invention is not particularly limited and can be performed by a person skilled in the art. Melt spinning is a technique in which a molten raw material composition obtained by heating the raw material composition to a temperature above the melting point using an extruder or the like is discharged from a spinneret into the atmosphere (for example, into air, or into cooled air as necessary). The positioning of the spinneret is not limited. However, it is preferable to face the spinneret downward so that the molten composition (molten filament) is discharged (drawn down) downward. The discharged molten filament is cooled and solidified in the atmosphere while being finely divided, and then taken at a constant speed. A large number of spinnerets may be installed in any group or pattern. When multiple spinnerets are used, the composition coming out of the spinneret can be guided by a mechanical mechanism to form an extruded filament. The number of spinnerets is not limited.

[0031] The atmosphere for melt spinning is not particularly limited, and may be various atmospheres such as an inert atmosphere and an ambient atmosphere, but an ambient atmosphere (air) is preferred from the viewpoint of cost. The temperature of the atmosphere may be any temperature lower than the melting point of the raw material composition, for example, -10°C to 50°C, more preferably 10°C to 40°C (considering cost).

[0032] It is also possible to melt the main component of the raw material composition (the thermoplastic polyurethane of the present invention) separately from the other components of the raw material composition (if present), thereby mixing the molten main component with the other components just before being discharged from the spinneret.

[0033] The apparatus for producing multifilaments by melt spinning is not particularly limited and is known to those skilled in the art. An example of such an apparatus is shown in FIG. 1. Generally, the melt spinning apparatus includes an extruder (not shown), a spinning package, godet rollers (GR1, GR2, GR3, etc.), and a winder. The spinning package is known in the art and mainly consists of a melt reservoir and a spinneret.

[0034] When one or more additives (other components) such as a crosslinking agent are used, at least one mixer, such as a static mixer or a dynamic mixer, preferably a static mixer, may be provided in the device. In this case, the main component including TPU, in one preferred embodiment consisting of TPU, is melted in the extruder separately from the crosslinking agent, and the crosslinking agent is mixed with the melted main component using a mixer, and then the molten mixed composition (i.e., the molten raw material composition) is discharged from the nozzle of the spinning head. The TPU of the raw material composition is crosslinked with the crosslinking agent during the melt spinning process. Alternatively, dried TPU granules are melted in the extruder, and the crosslinking agent (0-20%) is fed from the end of the extruder. The blend of crosslinking agent and TPU melt passes through the mixer and melt line, is metered, is forced into the spinning package, and finally exits from the spinneret.

[0035] The spinning temperature is a parameter of the spinning conditions for melt spinning. The spinning temperature is not only defined as the heating temperature in the extruder, but also as the heating temperature in the pipe for the raw material composition and in the spinning package. The spinning temperature is not particularly limited and can be appropriately changed according to the melting point of the raw material composition. From the viewpoint of spinnability, in the present invention, the spinning temperature is preferably 225°C or higher, but is preferably 250°C or lower, for example, 240°C or lower. In particular, when using a TPU having a high hardness (for example, a Shore hardness of more than 68D), a higher spinning temperature (for example, 225°C or higher) enables spinning at a faster spinning speed. From the viewpoint of suppressing thermal decomposition of the raw material composition, the spinning temperature is usually 240°C or lower, preferably 235°C or lower.

[0036] After exiting the spinneret, the extruded filaments are sent to step (b) to be drawn or oriented by passing through a set of godet rollers.

[0037] In step (b), the extruded filaments pass through a set of godet rollers. The set of godet rollers in step (b) of the method of the present invention may comprise two or more godet rollers arranged in series. Preferably, the set of godet rollers in step (b) comprises a first godet roller operating at a speed of 1000-4000 m / min, preferably 1000-3000 m / min, more preferably 1100-2300 m / min, more preferably 1200-2100 m / min. In a preferred embodiment of the present invention, the first godet roller operates at a surface temperature of 30-120°C, preferably 50-100°C, more preferably 60-90°C.

[0038] The operating speed of the godet rollers after the first godet roller can be selected by a person skilled in the art. In a preferred embodiment of the present invention, the set of godet rollers in step (b) comprises a first godet roller (GR1), a second godet roller (GR2), and a third godet roller (GR3) arranged in series. Preferably, the godet rollers operate at the following speeds, respectively: GR1: 1000 to 4000 m / min, preferably 1000 to 3000 m / min, more preferably 1100 to 2300 m / min, more preferably 1200 to 2100 m / min; GR2: 2000 to 5000 m / min, preferably 2000 to 4000 m / min, more preferably 2500 to 3500 m / min, more preferably 2600 to 3200 m / min; GR3: 2000 to 5000 m / min, preferably 2000 to 4000 m / min, more preferably 2200 to 3200 m / min, more preferably 2400 to 3000 m / min.

[0039] Preferably, the speed of the second godet roller is greater than the speed of both the first godet roller and the third godet roller.

[0040] Depending on the TPU material and / or end use, more godet rollers may be used. For example, the set of godet rollers in step (b) may comprise four or more godet rollers. In one embodiment of the present invention, in addition to the first godet roller, the second godet roller, and the third godet roller, the set of godet rollers in step (b) of the method of the present invention may further comprise one, two or three godet rollers.

[0041] In one embodiment of the present invention, the number of godet rollers in step (b) of the method of the present invention is three, i.e., only the first godet roller, the second godet roller and the third godet roller are used in step (b) of the method of the present invention.

[0042] In the present invention, "godet roller speed" and "godet roller operating speed" are used interchangeably and refer to the peripheral speed of the godet roller unless otherwise indicated.

[0043] The surface temperature of the godet rollers in step (b) of the present invention can be selected by a person skilled in the art. In one embodiment, the set of godet rollers in step (b) comprises a first godet roller, a second godet roller, and a third godet roller arranged in series, the first godet roller operates at a surface temperature of 30-120°C, preferably 50-100°C, more preferably 60-90°C, the second godet roller operates at a surface temperature of 60-170°C, preferably 80-160°C, more preferably 90-130°C, and the third godet roller operates at a surface temperature of 30-120°C, preferably 50-100°C, more preferably 60-90°C.

[0044] Preferably, the surface temperature of the second godet roller is higher than both the surface temperature of the first godet roller and the surface temperature of the third godet roller.

[0045] In one embodiment, in step (b) of the method of the present invention, the surface temperatures and speeds of the first godet roller (GR1), the second godet roller (GR2), and the third godet roller (GR3), respectively, are as follows: GR1: The surface temperature is 30 to 120°C, preferably 50 to 100°C, more preferably 60 to 90°C, and independently, the speed is 1000 to 4000 m / min, preferably 1000 to 3000 m / min, more preferably 1100 to 2300 m / min, more preferably 1200 to 2100 m / min. GR2: the surface temperature is 60 to 170°C, preferably 80 to 160°C, more preferably 90 to 130°C, and independently, the speed is 2000 to 5000 m / min, preferably 2000 to 4000 m / min, more preferably 2500 to 3500 m / min, more preferably 2600 to 3200 m / min; GR3: The surface temperature is 30 to 120°C, preferably 50 to 100°C, more preferably 60 to 90°C, and independently, the speed is 2000 to 5000 m / min, preferably 2000 to 4000 m / min, more preferably 2200 to 3200 m / min, more preferably 2400 to 3000 m / min.

[0046] Preferably, in step (b) of the method of the present invention, the surface temperatures and speeds of the first godet roller (GR1), the second godet roller (GR2) and the third godet roller (GR3) are respectively as follows: GR1: the surface temperature is 30 to 120°C, preferably 50 to 100°C, more preferably 60 to 90°C, and independently, the speed is 1100 to 2300 m / min, more preferably 1200 to 2100 m / min; GR2: the surface temperature is 60 to 170°C, preferably 80 to 160°C, more preferably 90 to 130°C, and independently, the speed is 2000 to 5000 m / min, preferably 2000 to 4000 m / min, more preferably 2500 to 3500 m / min, more preferably 2600 to 3200 m / min; GR3: The surface temperature is 30 to 120°C, preferably 50 to 100°C, more preferably 60 to 90°C, and independently, the speed is 2000 to 5000 m / min, preferably 2000 to 4000 m / min, more preferably 2200 to 3200 m / min, more preferably 2400 to 3000 m / min.

[0047] The method of the present invention further comprises a step (c) of winding the filament from step (b) onto a bobbin via a winder at a winding speed of 2000-5000 m / min, preferably 2000-4000 m / min, preferably 2100-2900 m / min, more preferably 2400-2900 m / min.

[0048] In a preferred embodiment of the present invention, a method for producing a multifilament by melt spinning a composition containing a thermoplastic polyurethane comprises the steps of: (a) passing the molten composition through a spinneret to obtain extruded filaments; (b) passing the extruded filament through a set of godet rollers; (c) winding the extruded filament of step (b) onto a bobbin via a winder at a winding speed of 2100 to 2900 m / min, more preferably 2400 to 2900 m / min; The thermoplastic polyurethanes have a Shore hardness, measured according to DIN ISO 7619-1, in the range of 68D to 90D, preferably in the range of 70D to 90D, more preferably in the range of 75D to 88D, more preferably in the range of 81D to 87D, even more preferably in the range of 82D to 86D.

[0049] In a more preferred embodiment of the present invention, a method for producing a multifilament by melt spinning a composition containing a thermoplastic polyurethane comprises the steps of: (a) passing the molten composition through a spinneret to obtain extruded filaments; (b) passing the extruded filament through a set of godet rollers; (c) winding the extruded filament of step (b) onto a bobbin via a winder at a winding speed of 2100 to 2900 m / min, more preferably 2400 to 2900 m / min; The thermoplastic polyurethanes have a Shore hardness, measured according to DIN ISO 7619-1, in the range of 81D to 87D, more preferably 82D to 86D.

[0050] In a more preferred embodiment of the present invention, a method for producing a multifilament by melt spinning a composition containing a thermoplastic polyurethane comprises the steps of: (a) passing the molten composition through a spinneret to obtain extruded filaments; (b) passing the extruded filaments through a set of godet rollers, the first godet roller operating at a speed of 1100-2300 m / min, more preferably 1200-2100 m / min, at a surface temperature of 30-120° C., preferably 50-100° C., more preferably 60-90° C.; (c) winding the extruded filament of step (b) onto a bobbin via a winder at a winding speed of 2000-5000 m / min, preferably 2000-4000 m / min, preferably 2100-2900 m / min, more preferably 2400-2900 m / min; The thermoplastic polyurethanes have a Shore hardness, measured according to DIN ISO 7619-1, in the range of 68D to 90D, preferably in the range of 70D to 90D, more preferably in the range of 75D to 88D, more preferably in the range of 81D to 87D, even more preferably in the range of 82D to 86D.

[0051] In an even more preferred embodiment of the present invention, a method for producing a multifilament fiber by melt spinning a composition containing a thermoplastic polyurethane comprises the steps of: (a) passing the molten composition through a spinneret to obtain extruded filaments; (b) passing the extruded filaments through a set of godet rollers, the first godet roller operating at a speed of 1100-2300 m / min, more preferably 1200-2100 m / min, at a surface temperature of 30-120° C., preferably 50-100° C., more preferably 60-90° C.; (c) winding the extruded filament of step (b) onto a bobbin via a winder at a winding speed of 2100 to 2900 m / min, more preferably 2400 to 2900 m / min; The thermoplastic polyurethanes have a Shore hardness, measured according to DIN ISO 7619-1, in the range of 81D to 87D, more preferably 82D to 86D.

[0052] In an even more preferred embodiment of the present invention, a method for producing a multifilament by melt spinning a composition containing a thermoplastic polyurethane comprises the steps of: (a) passing the molten composition through a spinneret to obtain extruded filaments; (b) passing the extruded filament through a set of godet rollers comprising a first godet roller (GR1), a second godet roller (GR2), and a third godet roller (GR3) arranged in series, wherein the surface temperatures and speeds of the first godet roller (GR1), the second godet roller (GR2), and the third godet roller (GR3), respectively, are as follows: GR1: the surface temperature is 30 to 120°C, preferably 50 to 100°C, more preferably 60 to 90°C, and independently, the speed is 1100 to 2300 m / min, more preferably 1200 to 2100 m / min; GR2: the surface temperature is 60 to 170°C, preferably 80 to 160°C, more preferably 90 to 130°C, and independently, the speed is 2000 to 5000 m / min, preferably 2000 to 4000 m / min, more preferably 2500 to 3500 m / min, more preferably 2600 to 3200 m / min; GR3: the surface temperature is 30 to 120°C, preferably 50 to 100°C, more preferably 60 to 90°C, and independently, the speed is 2000 to 5000 m / min, preferably 2000 to 4000 m / min, more preferably 2200 to 3200 m / min, more preferably 2400 to 3000 m / min; Preferably, the speed of the second godet roller is faster than both the speed of the first godet roller and the speed of the third godet roller, and the surface temperature of the second godet roller is higher than both the surface temperature of the first godet roller and the surface temperature of the third godet roller; (c) winding the extruded filament of step (b) onto a bobbin via a winder at a winding speed of 2100 to 2900 m / min, more preferably 2400 to 2900 m / min; The thermoplastic polyurethanes have a Shore hardness, measured according to DIN ISO 7619-1, in the range of 81D to 87D, more preferably 82D to 86D.

[0053] Optionally, the extruded filaments may be oiled, preferably after exiting the spinneret and before reaching the godet rollers. The oiling step oils the filaments, can reduce friction between the filaments and the metal / ceramic parts of the spinline, dissipates static charges that may arise due to contact between the filaments and machine parts, and holds the filaments together for easier unwinding from the spin cake. The filaments may be oiled with any conventional spinning oil.

[0054] The thickness of the rigid TPU multifilament obtained from the method of the present invention can be controlled in the range of 2-70 DPF (denier per filament) measured according to ISO2060:1994, for example in the range of 2-50 DPF, or 2-40 DPF, or 2-30 DPF, or 2-20 DPF, or 2-10 DPF, depending on different applications.

[0055] Thermoplastic Polyurethane The thermoplastic polyurethane used in the method of the present invention comprises the reaction product of (A) a polyol, (B) a diisocyanate, and (C) a chain extender.

[0056] The thermoplastic polyurethane used in the method of the present invention is generally obtained by reacting the essential components of polyol, diisocyanate and chain extender together, but not limited to, in the presence of a catalyst and / or aid (auxiliary agent) as necessary. In a preferred embodiment, the reaction can be a one-step reaction in which all of the essential components are reacted together in one step in the presence of optional components such as a catalyst and / or aid (auxiliary agent), or a multi-step reaction in which some of the polyol and diisocyanate are reacted together to form a prepolymer, and then the prepolymer and the remaining essential components are reacted together, preferably in the presence of a catalyst and / or aid (auxiliary agent).

[0057] Examples of catalysts (if used) in the reaction can be selected from, but are not limited to, trimethylamine, dimethylcyclohexylamine, N-methylmorpholine, N,N'-dimethylpiperazine, 2-(dimethylaminoethoxy)ethanol, diazabicyclo(2,2,2)octane and its analogs, in particular organometallic compounds such as titanium esters, iron compounds such as iron(III) acetylacetonate, tin compounds such as tin diacetate, tin dioctanoate and tin dilaurate, and tin dialkyl salts of aliphatic carboxylic acids such as dibutyltin diacetate and dibutyltin dilaurate and their equivalents. The amount of catalyst for the reaction can be determined by those skilled in the art according to the actual application.

[0058] Examples of the auxiliary agent are not particularly limited, and may be selected from surfactants, nucleating agents, lubrication and release aids, dyes, pigments, antioxidants (e.g., related to hydrolysis, light, heat and fading), ultraviolet absorbers, flame retardants, reinforcing agents, plasticizers or flow improvers, and crosslinking agents, and one or more selected from these may be used. The amount of the auxiliary agent may be determined by those skilled in the art according to the actual application.

[0059] The thermoplastic polyurethanes used in the process of the present invention have a Shore hardness, measured according to DIN ISO 7619-1, in the range of 68D to 90D, preferably in the range of 70D to 90D, more preferably in the range of 75D to 88D, more preferably in the range of 81D to 87D, even more preferably in the range of 82D to 86D.

[0060] The thermoplastic polyurethanes used in the process of the present invention may have a weight average molecular weight in the range of 50000 to 400000 g / mol, preferably 60000 to 300000 g / mol, for example 80000 to 200000 g / mol.

[0061] Polyol The thermoplastic polyurethane used in the method of the present invention has (A) a polyol as one of its raw materials.

[0062] The polyol used in the present invention may be a compound generally known as an isocyanate-reactive compound. In particular, the polyol used in the present invention may be selected from the group consisting of polyester polyols, polyether polyols, and any mixture thereof.

[0063] Preferably, the functionality of the polyol used in the present invention is in the range of 1.5-2.5, preferably 1.8-2.3, more preferably 1.9-2.1, for example 2.

[0064] Polyether polyols can be obtained by known methods, for example by polymerization of alkylene oxides in the presence of a catalyst to which at least one starter molecule containing 2 to 8, preferably 2 to 6, reactive hydrogen atoms has been added. As catalysts, alkali metal hydroxides such as sodium hydroxide or potassium hydroxide, or alkali metal alkoxides such as sodium methoxide, sodium ethoxide, potassium ethoxide, or potassium isopropoxide, or, in the case of cationic polymerization, Lewis acids such as antimony pentachloride, boron trifluoride etherate, or bleaching earth, can be used. In addition, complex metal cyanide compounds known as DMC catalysts can also be used as catalysts.

[0065] As alkylene oxide, preference is given to using one or more compounds having 2 to 4 carbon atoms in the alkylene group, such as, for example, ethylene oxide, 1,3-propylene oxide, tetrahydrofuran, 1,2- or 2,3-butylene oxide, preferably ethylene oxide, 1,2-propylene oxide and / or tetrahydrofuran, most preferably tetrahydrofuran, in each case either alone or in the form of a mixture.

[0066] Possible starter molecules are, for example, ethylene glycol, diethylene glycol, glycerol, trimethylolpropane, pentaerythritol, sugar derivatives such as sucrose, sugar alcohols such as sorbitol, methylamine, ethylamine, isopropylamine, butylamine, benzylamine, aniline, toluidine, toluenediamine, naphthylamine, ethylenediamine, diethylenetriamine, 4,4'-methylenedianiline, 1,3-propanediamine, 1,6-hexanediamine, ethanolamine, diethanolamine, triethanolamine and other di- or polyhydric alcohols or mono- or polyfunctional amines.

[0067] Examples of polyether polyols include ring-opened polymers of tetrahydrofuran (polytetramethylene glycol, PTMEG), natural oil-based polyether polyols such as alkoxylated castor oil, or other polyether polyols based on natural oils or fats, such as those obtained by ring-opening reactions of epoxidized unsaturated vegetable oils, and also saccharide-based polyether polyols.

[0068] Polyester polyols may be prepared by condensation of polyfunctional alcohols having 2-12 carbon atoms with polyfunctional carboxylic acids having 2-12 carbon atoms. The polyfunctional alcohols or polyfunctional carboxylic acids may have a functionality of about 2. Examples of polyfunctional alcohols may include ethylene glycol, diethylene glycol, butanediol, or combinations thereof. Examples of polyfunctional carboxylic acids may include succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, isomers of naphthalenedicarboxylic acid, or esters or anhydrides of the listed acids.

[0069] Preferably, the polyol used in the present invention is selected from the group consisting of polyester diols, polyether diols, and any mixtures thereof.

[0070] Diisocyanates The thermoplastic polyurethane used in the method of the present invention has (B) a diisocyanate as one of its raw materials.

[0071] The diisocyanate of the present invention may be selected from any organic compound having two isocyanate groups per molecule.

[0072] The diisocyanates of the present invention may be aliphatic diisocyanates, or araliphatic diisocyanates, or cycloaliphatic diisocyanates, or aromatic diisocyanates.

[0073] For example, the diisocyanate may contain 3 to 40 carbon atoms, and in various embodiments the diisocyanate may contain 4 to 20, 5 to 24, or 6 to 18 carbon atoms. In certain embodiments, the diisocyanate is a symmetric aliphatic or cycloaliphatic diisocyanate.

[0074] Preferred examples of suitable diisocyanates of the present invention include isomers of diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate, isomers of tolylene diisocyanate, 3,3'-dimethyldiphenyl diisocyanate, 1,2-diphenylethane diisocyanate, phenylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, heptamethylene diisocyanate, octamethylene diisocyanate, 2-methylpentamethylene-1,5-diisocyanate, 2-ethylbutylene-1,4-diisocyanate, isophorone diisocyanate, isomers of bis(isocyanatomethyl)cyclohexane, 1-methyl-2,4-cyclohexane diisocyanate, 1,2-dimethyldiphenyl ... More preferably, the diisocyanate is selected from the group consisting of isomers of diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate, isomers of tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and any mixtures thereof, and in particular, the diisocyanate is diphenylmethane diisocyanate, hexamethylene diisocyanate, and any mixtures thereof, in particular 4,4'-diphenylmethane diisocyanate.

[0075] In one embodiment of the present invention, only one diisocyanate is used.

[0076] Chain extender The thermoplastic polyurethane used in the method of the present invention has a chain extender (C) as one of the raw materials.

[0077] The chain extenders of the present invention may comprise aliphatic, araliphatic, aromatic and / or cycloaliphatic compounds having two or three functional groups. For example, chain extenders suitable for the present invention may be selected from di- or trifunctional amines and alcohols, in particular diols, triols or both, such as diamines and / or alkanediols having 2 to 10 carbon atoms in the alkylene group.

[0078] Examples of chain extenders suitable for the present invention include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,2-pentanediol, 1,3-pentanediol, 1,10-decanediol, 1,2-dihydroxycyclohexane, 1,3-dihydroxycyclohexane, 1,4-dihydroxycyclohexane, diethylene and triethylene glycols, dipropylene and tripropylene glycols, 1,6-hexanediol and bis(2-hydroxyethyl)hydroquinone, triols such as 1,2,4-trihydroxycyclohexane, 1,3,5-trihydroxycyclohexane, glycerol and trimethylolpropane. Particularly preferred chain extenders include 1,3-propanediol, 1,4-butanediol or 1,6-hexanediol. In certain cases, it is possible to use a mixture of two chain extenders.

[0079] Preferably, to form the thermoplastic polyurethane of the present invention, the polyol, diisocyanate, and chain extender are used in a molar ratio of isocyanate groups from the diisocyanate to isocyanate-reactive groups from both the polyol and the chain extender in the range of 0.9:1.0 to 1.1:1.0, preferably 0.95:1.0 to 1.05:1.0, and more preferably 0.97:1.0 to 1.03:1.0.

[0080] The multifilament of the present invention The multifilament of the present invention is produced from a composition containing the above-mentioned thermoplastic polyurethane. Preferably, the composition used in the method of the present invention consists essentially of thermoplastic polyurethane. The term "consists essentially of" means that the composition contains thermoplastic polyurethane and any unintended materials such as residues or contaminants. In other words, the composition contains 95% by weight (wt%) or more of thermoplastic polyurethane, preferably 99wt% or more, or preferably 99.5wt% or more, in particular 99.9wt% or more, or even 100wt% thermoplastic polyurethane.

[0081] The multifilaments obtained by the process of the present invention have significantly reduced boiling water shrinkage and significantly reduced elongation at break, have improved filament properties such as good uniformity and low defect rate, and provide improved properties for articles prepared from the multifilaments, such as good dimensional stability, good hand feel and low defect rate of articles such as knitted articles made from the multifilaments.

[0082] Preferably, the boiling water shrinkage of the multifilament obtained by the method of the present invention according to ASTM D2259-02 is 18% or less, preferably 17% or less, preferably 15% or less, even more preferably 13% or less, more preferably 10% or less.

[0083] Preferably, the multifilament obtained from the process of the present invention has an elongation at break according to ISO 2062:2009, method A of less than 55%, such as less than 50%, such as less than 46%, such as less than 40%, at relatively slow take-up speeds of less than 3000 m / min.

[0084] In some embodiments of the invention, the multifilaments resulting from the methods of the invention are of bicomponent or microtubular structure.

[0085] The multifilaments obtained from the method of the present invention can find use in various applications.For example, the multifilaments obtained from the method of the present invention are well suited for the manufacture of textiles.Such manufactured textiles can be used for the manufacture of articles, such as knitted or woven articles, such as clothing, shoes, or accessories, such as shoes, trousers, T-shirts, mesh chairs, watch bands, or hair bands.

[0086] Moreover, the multifilament obtained from the method of the present invention has a very low boiling water shrinkage rate, which makes it well suitable as the main raw material for fabrics. Therefore, the size and tactile sensation of the fabric made by the multifilament could be well controlled during steaming or ironing treatment.

[0087] By using ultra-hard TPU with hardness ranging from 68D to 90D in the method of the present invention, the boiling water shrinkage (BWS) of the resulting multifilament can be reduced to less than 20% as measured according to ASTM D2259-02 without the need for a post-spinning heat-setting process. By further increasing the hardness to more than 75D, the BWS of the resulting multifilament can be controlled to less than 15%. Furthermore, when the hardness is more than 80D, a very low BWS of less than 10% can be achieved.

[0088] The use of ultra-hard TPU in the inventive method for producing multifilaments also allows for a reduced elongation at break of the resulting multifilaments, which elongation at break can be less than 60% or even less than 40% at relatively slow winding speeds of less than 3000 m / min, measured according to method A of ISO 2062:2009.

[0089] The multifilaments of the present invention are directly produced by the process of the present invention without an additional heat-setting step. The present invention also provides a simplified process compared to conventional processes by omitting the heat-setting step to produce multifilaments with reduced boiling water shrinkage, reduced elongation at break, and improved filament properties. EXAMPLES

[0090] The invention will be better understood in light of the following non-limiting examples.

[0091] Abbreviation MDI: Diphenylmethane diisocyanate PTMEG: Polytetramethylene ether glycol PBA: Poly(1,4-butylene adipate)diol PMMA: Polymethyl methacrylate

[0092] material The TPU materials used in the examples are as follows: Hard TPU: TPU1 (obtained from BASF and having a hardness of 62D) with a weight average molecular weight of 80000-120000, based on PTMEG, MDI, and 1,4-butanediol with a number average molecular weight of 1000, was used to prepare the filaments.

[0093] Super hard TPU: TPU2 (obtained from BASF and having a hardness of 70D) with a weight average molecular weight of 100000-150000, based on PBA, MDI, and 1,4-butanediol with a number average molecular weight of 1000, was used to prepare the filaments.

[0094] TPU3, TPU4 and TPU5 (obtained from BASF and having hardness of 74D, 78D and 83D, respectively) with weight average molecular weight of 80000-120000 based on PTMEG, MDI and 1,4-butanediol with number average molecular weight of 1000 were used to prepare the filaments. [Table 1]

[0095] In the present invention, the weight average molecular weight of the thermoplastic polyurethanes is determined by gel permeation chromatography (GPC) according to DIN 55672-1 (date: August 2007). The procedure follows the following specifications: [Table 2]

[0096] A calibration plot (fifth order polynomial) is constructed from PMMA standards with different molecular weights by determining the retention time of each of the individual PMMA standards for a series of analyses.

[0097] Samples were dissolved at 4 mg / mL in a mixture of 99 wt % DMF and 1 wt % di-n-butylamine for at least 18 h and filtered through a 0.45 μm membrane filter before injection.

[0098] Method for manufacturing multifilament samples In the examples, the TPU materials described above were used for melt spinning.

[0099] The multifilament sample of this example is (a) passing a molten TPU composition having a temperature of 230° C. through a spinneret to obtain extruded TPU filaments; (a1) oiling the extruded TPU filaments of step (a) with a spinning oil manufactured by Takemoto Oil & Fat Co., Ltd. under the trade name "Delion F-1782"; (b) passing the extruded TPU filament of step (a1) through a set of godet rollers comprising a first godet roller (GR1), a second godet roller (GR2), and a third godet roller (GR3) arranged in series; (c) winding the TPU filament of step (b) onto a bobbin through a winding machine at a specified winding speed to obtain a final multifilament sample. The compound was prepared by a method comprising the steps of:

[0100] The composition, process parameters and results for each example multifilament sample are shown in Table 1. [Table 3]

Claims

1. A method for producing a multifilament by melt spinning a composition containing thermoplastic polyurethane, (a) Passing a molten composition through a spinneret to obtain an extruded filament, (b) Passing the extruded filament through a set of godet rollers, (c) The extruded filament from step (b) is wound onto a bobbin via a winding machine at a winding speed of 2000 to 5000 m / min, preferably 2000 to 4000 m / min, preferably 2100 to 2900 m / min, and more preferably 2400 to 2900 m / min. A method comprising, wherein the thermoplastic polyurethane has a Shore hardness in the range of 68D to 90D, preferably 70D to 90D, more preferably 75D to 88D, more preferably 81D to 87D, and even more preferably 82D to 86D, as measured according to DIN ISO 7619-1.

2. The set of godet rollers in step (b) comprises a first godet roller operating at a speed of 1000 to 4000 m / min, preferably 1000 to 3000 m / min, more preferably 1100 to 2300 m / min, and more preferably 1200 to 2100 m / min. Preferably, the first godet roller operates at a surface temperature of 30 to 120°C, preferably 50 to 100°C, and more preferably 60 to 90°C, according to claim 1.

3. The set of godette rollers in step (b) comprises a first godette roller, a second godette roller, and a third godette roller arranged in series, The first godet roller operates at a speed of 1000 to 4000 m / min, preferably 1000 to 3000 m / min, more preferably 1100 to 2300 m / min, and more preferably 1200 to 2100 m / min. The second godet roller operates at a speed of 2000 to 5000 m / min, preferably 2000 to 4000 m / min, more preferably 2500 to 3500 m / min, and more preferably 2600 to 3200 m / min, and The third godet roller operates at a speed of 2000 to 5000 m / min, preferably 2000 to 4000 m / min, more preferably 2200 to 3200 m / min, and more preferably 2400 to 3000 m / min. Preferably, the method according to claim 1, wherein the speed of the second godet roller is faster than the speed of the first godet roller and the speed of the third godet roller.

4. The first godet roller operates at a surface temperature of 30 to 120°C, preferably 50 to 100°C, more preferably 60 to 90°C. The second godet roller operates at a surface temperature of 60 to 170°C, preferably 80 to 160°C, more preferably 90 to 130°C. The third godet roller operates at a surface temperature of 30 to 120°C, preferably 50 to 100°C, more preferably 60 to 90°C. Preferably, the method according to claim 3, wherein the surface temperature of the second godet roller is higher than the surface temperature of the first godet roller and the surface temperature of the third godet roller.

5. (a1) Before step (b), supply spinning oil to the extruded filament. The method according to claim 1, further comprising:

6. The aforementioned thermoplastic polyurethane (A) Polyol, (B) Diisocyanates, and (C) Chain extender The method according to claim 1, comprising a reaction product wherein the polyol is selected from the group consisting of polyether polyols, polyester polyols, and any mixture thereof.

7. A multifilament obtained by the method according to any one of claims 1 to 6.

8. The multifilament according to claim 7, wherein the boiling water shrinkage rate of the multifilament according to ASTM D2259-02 is 18% or less, preferably 17% or less, more preferably 15% or less, even more preferably 13% or less, and even more preferably 10% or less.

9. The multifilament according to claim 7, wherein the elongation at break of the multifilament is measured according to Method A of ISO 2062:2009 and is less than 55%, for example less than 50%, for example less than 46%, for example less than 40%, at a relatively slow winding speed of less than 3000 m / min.

10. The multifilament according to claim 7, having a two-component structure or a microtubular structure.

11. Use of the multifilament according to claim 7 in the manufacture of clothing, footwear, or accessories such as shoes, trousers, T-shirts, mesh chairs, watch bands, or headbands.

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