CN111575817A

CN111575817A - Method for manufacturing thermoplastic polyurethane fiber

Info

Publication number: CN111575817A
Application number: CN201911354522.0A
Authority: CN
Inventors: 甘根娣; 朱利忠; 邹圣杰; 黄大理
Original assignee: Haining Xingao Fiber Co ltd
Current assignee: Haining Xingao Fiber Co ltd
Priority date: 2019-02-19
Filing date: 2019-12-26
Publication date: 2020-08-25
Also published as: CN113474495B; JP2022522126A; CN113474495A; KR20210124275A; US20220145496A1; TW202031709A; EP3927870A1; WO2020169417A1

Abstract

The invention relates to a method for producing thermoplastic polyurethane fibers. The method includes first melt spinning a composition including a Thermoplastic Polyurethane (TPU) resin to obtain a fiber to be heat-set, and heat-setting the fiber to be heat-set, wherein the heat-setting step includes heat-treating and twisting to form the thermoplastic polyurethane fiber. Wherein the heat treating comprises heating the fiber to be heat-set at about 160 ℃ to about 170 ℃ to shrink it.

Description

Method for manufacturing thermoplastic polyurethane fiber

Technical Field

The invention relates to a method for manufacturing thermoplastic polyurethane fibers.

Background

Thermoplastic polyurethanes (hereinafter "TPU") have excellent physical properties as well as processability. More importantly, TPU is an environmentally friendly material that can be either naturally degraded in soil or recycled for reuse in raw form. Thus, TPU has received much attention in recent years and is being attempted to be applied to many technical fields.

In the field of shoe making, TPU has been used to make shoe soles and their related parts. However, the uppers of most current footwear products with TPU as the sole are still made of other materials. Although such products have a recyclable TPU sole, their recycling is still extremely difficult and/or has an excessively high recycling cost, since the upper is made of a different material. Thus, it has become a research direction in the field of shoe making to produce shoe uppers and other components from TPU to produce shoe articles that are entirely comprised of TPU that can be recycled.

It is known to include TPU fibers as an auxiliary material in fabrics. TPU fibers as an auxiliary material generally have a higher elasticity and a lower modulus. Highly elastic TPU fibers are used in fabrics as an adjunct material, commonly referred to as spandex. However, high elastic TPU fibers are currently used only as an elastic component of fabrics due to their performance characteristics, and are difficult to use as a main raw material of fabrics.

The low-elasticity high-modulus TPU fiber has similar rigidity to that of polyamide fiber and polyester fiber, has high toughness, high modulus and low elongation, and is a beneficial material which can replace the polyamide fiber and the polyester fiber in the related art. The TPU fiber with low elasticity and high modulus can be used as an auxiliary material of the fabric and can also be used as a raw material of the fabric. When the TPU fiber with low elasticity and high modulus is used for manufacturing the vamp, the TPU fiber can be recycled together with the TPU sole, and the friction performance of the TPU fiber is superior to that of the vamp made of the polyamide fiber or the polyester fiber. Thus, for the enormous annual footwear market, the use of TPU fibers for upper making is of great significance for environmental protection.

PCT International patent application WO 2018/146192A 1 discloses a process for melt spinning starting compositions comprising TPU at relatively high spinning speeds (> 2000 m/min). However, the TPU fibers produced by this process have a large degree of shrinkage when treated with boiling water or steam. Accordingly, articles woven with such TPU fibers also shrink to a greater degree (typically 20% to 40% shrinkage) during steam or iron ironing. Such a large degree of shrinkage reduces the original dimensions of the article, making the article more compact and rigid. Thus, the original good touch of the article is deteriorated, so that the article feels like a plastic article.

There are a number of prior art attempts to solve the problem of shrinkage of TPU fibers. For example, U.S. patent application US2009/0311529 a1 discloses producing high tenacity, high modulus TPU monofilaments (rigid TPU monofilaments) in an extrusion, orientation and final dynamic annealing process. The TPU monofilament produced by this process has a shrinkage at 140 ℃ as low as 10% and a denier of 80 to 20000. During production, the extrudate, having a diameter of 0.95mm, is subjected to orientation treatment after quenching. Thus, the two steps of extrusion and orientation are not continuous. In addition, US2009/0311529 a1 also does not mention techniques for high spinning speeds.

Korean patent KR 100587903B 1 discloses a dry spinning process for producing a polyurethane fiber with low shrinkage. The elastic fiber after the spinning process is heat-treated in a heat treatment apparatus at a temperature higher than 100 ℃ for 0.01 to 0.05 seconds. Suitable heat treatment equipment includes heated tubes or rolls having a length of 20 to 30 cm. The polyurethane fibers obtained have a boiling water shrinkage of less than 7% and a shrinkage of less than 5% after one hour of heat treatment in a hot-air oven at 100 ℃. KR 100587903B 1 relates to dry spinning processes and does not mention melt spinning processes, especially at high spinning speeds.

US patent application US 5,066,439 a discloses a spin-draw process for producing polyester fibers with dimensional stability. The polyester fiber is obtained by melt spinning polyethylene terephthalate, stretching, merging and relaxation heat treatment, and has high strength and low shrinkage. In the drawing step, a hot plate at a temperature of 250 to 500 ℃ is used to assist relaxation of the fibers.

US patent application US 2009/0124149 a1 discloses a high tenacity low shrinkage multifilament polyamide (nylon) yarn and a process for making the same. The fabrication process involves spinning-drawing molten nylon, relaxing and controlling the yarn tension, and then winding the yarn.

Chinese patent CN 102168319B discloses a polyester industrial yarn with high strength, high modulus and low shrinkage and a production process thereof. The production process relaxes the tow after the spinning step.

PCT international patent application PCT/CN2019/075473 (hereinafter the' 473 application) relates to a process for producing low shrinkage TPU fibers by a melt spinning-heat setting process. High spinning speeds (> 2000m/min) are used in the melt spinning step. The heat setting step is divided into an online mode and an offline mode. The online heat setting is carried out by passing TPU fibers through a plurality of hot rollers. The heat setting mode has high requirements on production equipment (a plurality of hot rollers are required to be arranged), in addition, the retention time of the fiber in the heat setting step is longer, the production cost of the TPU fiber is increased, and the operability and the controllability are lower. The off-line heat setting of this application is performed by placing the cake in a steam box, which allows the fiber to shrink set for a certain time at a certain temperature until it releases all the stress. And (4) rewinding and oiling the shrunk spinning cake, and then spooling and twisting. Under the mode of off-line heat setting, the fibers of the inner layer and the outer layer of the spinning cake have different shrinkage rates (the shrinkage difference rate can be up to more than 5 percent) due to different exposure degrees of heating and air (particularly oxygen), so that the quality of the fibers of the inner layer and the outer layer of the spinning cake has larger difference. For example, the inner fiber of the spinning cake treated by the off-line heat setting mode is not discolored and has higher hardness, and the outer fiber of the spinning cake is yellowed and is relatively softer. More importantly, the differential change of the shrinkage of the inner and outer layers of the spinning cake is non-linear and unpredictable, resulting in inconsistent size, color and/or hardness of different vamps or even the same vamp made of the TPU fibers which are not processed in an online heat setting mode, and poor production stability. Therefore, the off-line heat setting mode is not suitable for industrial mass production of TPU fibers for manufacturing shoe bodies.

European patent EP 3081109B 1 discloses a solution for making a body and a sole from TPU. However, the published technical proposal only refers to the TPU fiber to make the shoe body in a general way, and the specific composition and the production process of the TPU fiber are not involved.

Thus, despite the research and exploration of the prior art regarding the production process and use of TPU fibers, there is still a need in the market today for a production process that enables the industrial mass production of TPU fibers having low shrinkage and high strength.

Disclosure of Invention

One aspect of the present invention relates to a method for producing thermoplastic polyurethane fibers. The method includes first melt spinning a composition including a Thermoplastic Polyurethane (TPU) resin to obtain a fiber to be heat-set, and heat-setting the fiber to be heat-set, wherein the heat-setting step includes heat-treating and twisting to form the thermoplastic polyurethane fiber. Wherein the heat treating comprises heating the fiber to be heat-set at about 160 ℃ to about 170 ℃ to shrink it.

The invention provides a production process capable of industrially producing TPU fibers. The TPU fiber produced by the process has the characteristics of high strength and low shrinkage rate, and meets the requirements of shoe body manufacturing. In addition, the TPU fibers produced by the process of the invention have properties close to those of each layer of a spinning cake, which is beneficial to the stability of industrial production.

Drawings

In order to facilitate a clear description of the invention, it will be described below with reference to the accompanying drawings, which illustrate possible embodiments of the invention. It will be appreciated by those skilled in the art that other embodiments than those illustrated in the drawings are possible and are encompassed within the scope of the invention. The specific examples of the drawings do not limit the scope of the invention, nor do they limit the generality of the preceding description of the invention.

FIG. 1 illustrates an exemplary apparatus of a melt spinning process;

FIG. 2 illustrates a heat-setting process according to one embodiment of the present invention; and

fig. 3 illustrates a heat-setting method according to another embodiment of the present invention.

Those skilled in the art will appreciate that the drawings in this application are for reference purposes only and do not necessarily reflect the scale or dimensions of the embodiments of the invention.

Detailed Description

All measurements, weights, lengths, etc. in this application are measured in metric units and all temperatures are in degrees celsius unless otherwise specifically stated. Unless otherwise specifically stated, all materials, compounds, chemicals, etc. described herein are commonly available and/or commercially standardized products, available from a wide variety of suppliers and sources worldwide.

In one embodiment, the heat treatment is performed before twisting. In another embodiment, the heat treatment is performed after twisting.

In one embodiment, the heat setting step further comprises oiling. Wherein the fiber can be oiled using a spin finish.

In one embodiment, the melt spinning step comprises melt spinning the composition comprising the TPU resin at a spinning speed of about 2000-6500 m/min; or melt spinning the composition at a spinning speed of about 2000-.

In one embodiment, the melt spinning step comprises passing the fiber to be heat-set through about 2 to about 6 godets. Alternatively, the godet roll may be a heated roll.

In another embodiment, the fiber to be heat-set is passed through 3 godets. Alternatively, all three godet rolls may be thermo rolls. Wherein the temperature of the first godet roll may be from about 30 ℃ to about 150 ℃; or from about 60 ℃ to about 100 ℃. The temperature of the second godet roll may be from about 60 ℃ to about 200 ℃; or from about 100 ℃ to about 160 ℃. The temperature of the third godet roll may be about 30 ℃ to 150 ℃; or about 60 c to 100 c.

In one embodiment, the speed of the first godet may be about 1000-; or about 1000 and 4500 m/min. The speed of the second godet roll may be about 2000 and 6000 m/min; or about 2000-4500 m/min. The speed of the third godet may be about 2000 and 6000 m/min; or about 2000-4500 m/min.

In one embodiment, the heat treating of the fiber to be heat-set comprises passing the fiber to be heat-set through a heat pipe. In another embodiment, the fiber to be heat-set may be passed through a heat pipe at a speed of about 20-200 m/min; or passing through the heat pipe at a speed of 30-150 m/min; or passing through the heat pipe at a speed of 40-120 m/min. Specifically, the heat pipe passing speed may be about 20m/min, 30m/min, 40m/min, 50m/min, 60m/min, 70m/min, 80m/min, 90m/min, 100m/min, 110m/min, 120m/min, 130m/min, 140m/min, 150m/min, 160m/min, 170m/min, 180m/min, 190m/min, or 200 m/min.

In one embodiment, the length of the heat pipe is about 70-120 m. Specifically, the length of the heat pipe may be about 70m, about 75m, about 80m, about 85m, about 90m, about 95m, about 100m, about 105m, about 110m, about 115m, or about 120 m.

In one embodiment, the heat pipe residence time for the fiber to be heat set is from 0.5 to 5 seconds.

In one embodiment, the heat treatment, oiling and twisting are performed in a continuous manner. The method has high production efficiency and can reduce the production cost of the TPU fiber.

In one embodiment, the production method of the present invention further comprises winding the fiber to be heat-treated after the melt-spinning step in preparation for the heat-setting step. In another embodiment, the production process of the present invention further comprises unwinding the fiber to be heat-set prior to the heat-setting step.

In one embodiment, the TPU fibers produced according to the present invention have a denier of about 30 to 600 de; about 100-; or about 200 and 400 de. In particular, the titer of the TPU fibers produced according to the present invention may be about 100de, 200de, 300de, 400de, 500de, or 600 de.

In one embodiment, the TPU fibers produced according to the present invention have a denier per filament of about 3 to 50; 5-30 denier per filament; or 6-20 denier per filament. Specifically, the TPU fibers produced according to the present invention can have a denier per filament of about 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, 14.5, 15, 15.5, 16, 16.5, 17, 17.5, 18, 18.5, 19, 19.5, or 20.

In one embodiment, the TPU has a hardness of Shore 80A to Shore 80D, a hardness of Shore 80A to Shore 74D, or a hardness of Shore 90A to Shore 70D. The hardness is determined in accordance with DIN ISO 7619-1.

In one embodiment, the TPU is the reaction product of an isocyanate or salt, a polyol, and a chain extender. Optionally, the reaction is carried out in the presence of a catalyst and/or an adjuvant.

In one embodiment, the isocyanate or salt is selected from the group consisting of diphenylmethane diisocyanates (e.g., 2, 2 '-diphenylmethane diisocyanate, 2, 4' -diphenylmethane diisocyanate, and 4, 4 '-diphenylmethane diisocyanate), 1, 5-naphthalene diisocyanate, 2, 4-toluene diisocyanate, 2, 6-toluene diisocyanate, 3' -dimethylbiphenyl diisocyanate, 1, 2-diphenylethane diisocyanate, p-phenylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, heptamethylene diisocyanate, octamethylene diisocyanate, 1, 5-diisocyanato-2-methylpentane, 1, 4-diisocyanato-2-ethylbutane, sodium diisocyanato-dimethylmethane diisocyanate, 1, 5-pentamethylene diisocyanate, 1, 4-tetramethylene diisocyanate, isophorone diisocyanate, 1, 3-bis (isocyanatomethyl) cyclohexane, 1, 4-cyclohexane diisocyanate, 1-methyl-2, 6-cyclohexane diisocyanate, 4 '-dicyclohexylmethane diisocyanate, 2' -dicycloethylmethane diisocyanate.

In another embodiment, the isocyanate or salt is selected from the group consisting of 2, 2 ' -diphenylmethane diisocyanate, 2, 4 ' -diphenylmethane diisocyanate, 4 ' -diphenylmethane diisocyanate, 1, 5-naphthalene diisocyanate, 2, 4-toluene diisocyanate, 2, 6-toluene diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate. In another embodiment, the isocyanate is selected from the group consisting of 2, 2 ' -diphenylmethane diisocyanate, 2, 4 ' -diphenylmethane diisocyanate, 4 ' -diphenylmethane diisocyanate, and hexamethylene diisocyanate. In yet another embodiment, the isocyanate is selected from the group consisting of 2, 2 ' -diphenylmethane diisocyanate, 2, 4 ' -diphenylmethane diisocyanate, and 4, 4 ' -diphenylmethane diisocyanate.

In one embodiment, the polyol is selected from the group consisting of polyester polyols, polyether polyols, polycaprolactone polyols, and polycarbonate polyols. In another embodiment, the polyol is selected from the group consisting of polyester polyols and polyether polyols. In yet another embodiment, the polyol is polytetramethylene ether glycol.

In one embodiment, the chain extender is selected from the group consisting of ethylene glycol, 1, 2-propanediol, 1, 3-propanediol, 1, 2-pentanediol, 1, 3-pentanediol, 1, 10-decanediol, 1, 2-cyclohexanediol, 1, 3-cyclohexanediol, 1, 4-cyclohexanediol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, 1, 4-butanediol, 1, 6-hexanediol, bis (2-hydroxyethyl) hydroquinone and triols. In another embodiment, the chain extender is selected from the group consisting of 1, 3-propanediol, 1, 4-butanediol, and 1, 6-hexanediol. Wherein the triol may be selected from the group consisting of 1, 2, 4-trihydroxycyclohexane, 1, 3, 5-trihydroxycyclohexane, glycerol and trimethylolpropane.

(A) Step of melt spinning

The melt spinning process, also called melt spinning, is a process in which a raw material is heated to a temperature equal to or higher than its melting point so that it is in a molten state, the raw material in the molten state (i.e., a "melt") is discharged through a spinneret into a gas phase atmosphere (e.g., air or cooled air) using an extruder or the like, and the discharged melt stream is cooled and solidified in the gas phase atmosphere to form fibers. The discharged melt stream is usually cooled to solidify and then drawn at high speed into filaments by a take-up device.

In the melt spinning process, the main component (e.g., TPU) and other components of the raw materials may be heated separately to a molten state and mixed before being extruded in an extruder.

Melt spinning equipment is known in the art. Fig. 1 shows a melt spinning device comprising an extruder (not shown in fig. 1), a spinning pack 1 and a winding device 2. Spin packs are known in the art and consist primarily of a melt distribution plate and a spinneret.

The raw material composition or its main components enter the extruder through the hopper and become molten state, after which they are discharged through the spinneret of the spinning pack to form fibers in a solidified state.

One or more additives, such as a cross-linking agent, may be included in the raw material composition. The production plant may be equipped with at least one mixer, for example a dynamic or static mixer, preferably a static mixer. In one embodiment, the main component of the raw material composition comprises or consists of TPU. In this embodiment, the TPU is brought into the molten state in the extruder without the crosslinking agent, and the crosslinking agent and the molten main component are mixed by means of a mixer. Thereafter, the mixed composition (i.e., the raw material composition and the crosslinking agent) is discharged from the spinneret in a molten state. The TPU in the raw material composition is crosslinked with the crosslinking agent in the melt spinning process. Alternatively, the dried TPU granules are melted in an extruder and the crosslinking agent (0-20%) is added at the end of the extruder. The cross-linking agent and TPU melt mixture passes through a mixer and a melt pipeline together, is metered by a metering pump, is pumped to a spinning assembly, and is finally extruded from a spinneret plate. In one embodiment, the feedstock composition used in the present invention does not use a crosslinking agent.

After being extruded from the spinneret, the TPU fibers are drawn or oriented via a series of godets having different line speed ratios (e.g., godets GR1, GR2, and GR3 in fig. 1). It should be noted that the number of godets is not limited to 3; the godet rolls may be 2 or more and 6 or less, for example 2, 3, 4, 5 or 6. However, the number of godets is preferably 3.

During spinning, the fibers may be treated via shrinkage control. The process fixes the degree of orientation of the TPU fibers by heating the godet rolls to a surface temperature such that the shrinkage caused by high speed spinning can be controlled to, for example, less than 30%.

The surface temperature and speed of the godets GR1, GR2, GR3 may be set as follows:

■ GR 1: the temperature may be 30-150 ℃, preferably 60-100 ℃; the speed is 1000-6000m/min, preferably 1000-4500 m/min;

GR 2: the temperature may be 60-200 ℃, preferably 100-160 ℃; the speed is 2000-6000m/min, preferably 2000-4500 m/min; and

■ GR 3: the temperature may be 30-150 ℃, preferably 60-100 ℃; the speed is 2000-6000m/min, preferably 2000-4500 m/min.

In the present application, the speed of the godet roll refers to its peripheral speed, unless explicitly stated otherwise.

At the end of the melt-spinning step, the TPU fibers are wound onto bobbins by the winding device 2 in FIG. 1 at high speed (e.g. 2000-. In the present invention, the spinning speed refers to a winding speed.

Alternatively, the fibers may be oiled before the fibers extruded from the spinneret reach the godet rolls. The oiling step may lubricate the fibers to reduce friction between the metal and ceramic parts and the fibers in the spinning line. In addition, the oiling can also dissipate static electricity generated by the contact of the fibers with machine parts, gathering the fibers together for unwinding from the cake. The fibers may be oiled with conventional spin finishes.

The gas phase in the melt spinning process can be chosen from a wide variety of gases, such as an inert gas atmosphere or an air atmosphere. An air atmosphere (i.e., air) is preferred from the viewpoint of cost. The temperature of the gas phase may be any temperature below the melting point of the feedstock composition, from-10 ℃ to 50 ℃, preferably from 10 ℃ to 40 ℃ from a cost standpoint.

The parameters of spinning are not particularly limited except for the spinning speed, but preferred parameters are listed below.

Spinning temperature

In this application, spinning temperature refers not only to the temperature in the extruder, but also to the temperature in the polymer line and spin pack assembly. The setting of the spinning temperature is not particularly limited, and may be appropriately adjusted depending on the melting point of the raw material composition. From the viewpoint of spinnability, the spinning temperature is usually 180 ℃ or higher, preferably 200 ℃ or higher, more preferably 220 ℃ or higher, but preferably not higher than 260 ℃. Higher spinning temperatures (e.g., above 220 ℃, preferably 225 ℃ or higher) allow higher spinning speeds, particularly when TPU having high hardness is used (e.g., shore 60D or higher). The spinning temperature is usually 240 ℃ or lower, preferably 235 ℃ or lower, from the viewpoint of suppressing thermal decomposition of the raw material composition.

Raw material composition

The raw material composition may include a resin including the TPU, preferably the resin consists essentially of the TPU. By "consisting essentially of TPU" is meant that the resin includes TPU as well as other materials such as residues, contaminants, or the like. In other words, the resin comprises 95% (wt%) or more by mass of TPU, preferably 99 wt% or more, more preferably 99.5 wt% or more, especially 99.9 wt% or more, even 100 wt% of TPU. The selection of the TPU is not limited and one or more TPU may be selected. Suitable TPUs are described below.

TPU

In the present invention, there is no particular requirement for a suitable TPU. In general, the TPU may be prepared by reacting (a) an isocyanate, preferably an organic diisocyanate; (b) a polyol; and (c) a chain extender as the primary reactant. The chain extender is typically a short chain polyol, such as a short chain diol. If desired, (d) a catalyst and/or (e) an auxiliary may also be added to the reaction. In a preferred embodiment, the chain extender has a molecular weight of from 50g/mol to 499 g/mol. Polyols, also known as long-chain polyols, generally have a number average molecular weight of from 500g/mol to 8000 g/mol. The reaction may be a one-step reaction, with the main reactants (a) - (c) reacting with each other. In a preferred embodiment, the reaction may be carried out in the presence of optional reactants (d) and (e). Alternatively, the reaction may be carried out in multiple stages, such that two or more of the primary reactants (a) - (c) react with each other to form a prepolymer, and the prepolymer is reacted with the other reactants, preferably in the presence of optional reactants (d) and (e).

The hardness of the TPU IS measured in accordance with DIN IS 07619-1. The hardness of the TPU is generally from Shore 80A to Shore 80D, preferably from Shore 80A to Shore 74D, and more preferably from Shore 90A to Shore 70D.

The weight average molecular weight of the TPU is not limited, and is generally from 50,000 to 800,000, preferably from 80,000 to 600,000, and more preferably from 80,000 to 400,000.

As isocyanates or esters of the reactant (a), aromatic, aliphatic and/or araliphatic isocyanates or esters known in the art, preferably diisocyanates or esters, can be used. Specifically, one or more of the following substances may be selected: diphenylmethane diisocyanates (MDI), such as 2, 2 ' -, 2, 4 ' -, 4 ' -diphenylmethane diisocyanate; 1, 5-Naphthalene Diisocyanate (NDI); 2, 4-, 2, 6-Toluene Diisocyanate (TDI); 3, 3' -dimethylbiphenyl diisocyanate; 1, 2-diphenylethane diisocyanate; p-phenylene diisocyanate; trimethylene diisocyanate; tetramethylene diisocyanate; pentamethylene diisocyanate; hexamethylene diisocyanate; heptamethylene diisocyanate; octamethylene diisocyanate; 1, 5-diisocyanato-2-methylpentane; 1, 4-diisocyanato-2-ethylbutane; isophorone diisocyanate (IPDI); 1, 3-, 1, 4-bis (isocyanatomethyl) cyclohexane (HXDI); 1, 4-cyclohexane diisocyanate; 1-methyl-2, 4-cyclohexane diisocyanate, 1-methyl-2, 6-cyclohexane diisocyanate; and/or 4, 4 '-, 2' -dicyclohexylmethane diisocyanate. Preferably, the isocyanate is 2, 2 ' -, 2, 4 ' -, 4 ' -diphenylmethane diisocyanate (MDI); 1, 5-Naphthalene Diisocyanate (NDI); 2, 4-, 2, 6-Toluene Diisocyanate (TDI); hexamethylene Diisocyanate (HDI) and/or isophorone diisocyanate (IPDI). In particular, the isocyanate is MDI and/or HDI. More preferably, the isocyanate is MDI.

As the polyol as the reactant (b), a polyol which is known in the art to be reactive with isocyanate or ester can be used. For example, polyester polyols, polyether polyols, polycaprolactone polyols and/or polycarbonate polyols may be suitable. These compounds are all covered by the term "polyol" in the art. Preferably, the reactant (b) may be a polyether polyol or a polyester polyol. In some cases, mixtures of polyether polyols and polyester polyols may be used. In general, the polyol has a number average molecular weight of, for example, 500g/mol to 8000g/mol, preferably 600g/mol to 6000g/mol, more preferably 700g/mol to 4000g/mol, and further preferably 800g/mol to 3000 g/mol. The molecular weight herein means a number average molecular weight.

Among these polyols, polyether polyols or polyester polyols may be preferred. And, of these two polyols, polyether polyol may be preferable in view of resistance to microbial attack and water resistance, and polyester polyol may be preferable when mechanical properties are taken into consideration.

Polyether polyols can be synthesized in a manner known in the art, for example by polymerization of alkylene oxides and initiators having active hydrogen atoms (2 to 8 active hydrogen atoms, preferably 2 to 6 active hydrogen atoms) in the presence of a catalyst. The catalyst may be chosen from alkali metal hydroxides (such as potassium hydroxide or sodium hydroxide), alkali metal alkoxides (such as sodium methoxide, sodium or potassium ethoxide or potassium isopropoxide) or, in the case of cationic polymerization, from Lewis acids (such as antimony pentachloride, boron trifluoride etherate or fuller's earth). In addition, Double Metal Cyanide (DMC) can also be used as a catalyst.

For the choice of alkylene oxide, preference is given to compounds having from 2 to 4 carbon atoms in the alkyl moiety, for example ethylene oxide, 1, 2-propylene oxide, tetrahydrofuran, 1, 2-or 2, 3-butylene oxide. The alkylene oxides can be used individually or in mixtures. Ethylene oxide, 1, 2-propylene oxide and/or tetrahydrofuran are preferred. Tetrahydrofuran is more preferred.

Possible initiators may be, for example, ethylene glycol, diethylene glycol, glycerol, trimethylolpropane, pentaerythritol, sugar derivatives (e.g. sucrose, sugar alcohols such as sorbitol), methylamine, ethylamine, isopropylamine, butylamine, aniline, benzylamine, toluidine, diaminotoluene, naphthylamine, ethylenediamine, diethylenetriamine, 4' -methylenedianiline, 1, 3-propanediamine, 1, 6-hexanediamine, ethanolamine, diethanolamine, triethanolamine, other dihydroxy or polyhydroxy alcohols or monofunctional or polyfunctional amines.

Examples of polyether polyols may include ring-opened polymers of tetrahydrofuran (polytetramethylene ether glycol, PTMEG), natural oil-based polyols such as castor oil or natural oil or fatty acid alkoxylates.

The polyester polyol can be prepared by condensation reaction of a polyfunctional alcohol having 2 to 12 carbon atoms and a polyfunctional carboxylic acid having 2 to 12 carbon atoms. The functionality of the polyfunctional alcohol or carboxylic acid may be about 2. The polyfunctional alcohol may be ethylene glycol, diethylene glycol, butanediol, or combinations thereof. The polyfunctional carboxylic acid may be succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, isomers of naphthalenedicarboxylic acids, as well as esters or anhydrides of these acids.

The polyether polyols or polyester polyols described herein have a hydroxyl number of from about 15 to about 225mg KOH/g, preferably a hydroxyl number of from about 20 to about 190mg KOH/g, more preferably a hydroxyl number of from about 30 to about 160mg KOH/g, and most preferably a hydroxyl number of from about 40 to about 140mg KOH/g.

For the chain extender of reactant (c), difunctional or trifunctional amines and alcohols, in particular diols, triols or both, can be used. Difunctional compounds of this type are known as chain extenders, while trifunctional or higher functional compounds are known as crosslinkers. Exemplary compounds may include ethylene glycol, 1, 2-propanediol, 1, 3-propanediol, 1, 4-butanediol, 1, 2-pentanediol, 1, 3-pentanediol, 1, 10-decanediol, 1, 2-cyclohexanediol, 1, 3-cyclohexanediol, 1, 4-cyclohexanediol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, 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 some cases, a mixture of two chain extenders may be used.

The hardness of the TPU can be controlled by the molar ratio of the reactants (b) and (c). Specifically, the ratio of the molar amount of the reactant (b), the polyol, to the total molar amount of the reactant (c), the chain extender, is in the range of 10: 1 to 1: 10, in particular in the range of 1: 1 to 1: 5. The hardness of the TPU increases with increasing amount of chain extender of reactant (c).

Reactant (d) catalyst is optional. Examples thereof may include: trimethylamine, dimethylcyclohexylamine, N-methylmorpholine, N' -dimethylpiperazine, 2- (dimethylaminoethoxy) ethanol, 1, 4-diazidobicyclo [2.2.2] octane and derivatives thereof; in addition, organometallic compounds, such as titanates; iron-containing compounds, such as iron (III) acetylacetonate; tin-containing compounds such as stannous acetate, stannous octoate and stannous laurate, and equivalents thereof. The catalyst is used in an amount of usually 0.0001 to 0.1 part by mass per 100 parts by mass of the long-chain polyol.

The reactant (e) adjuvant is optional. It includes: surface-active, nucleating agents, slip agents (gelling aid) and mould release agents (removing aid), dyes, pigments, antioxidants (e.g. for hydrolysis, light, heat and discoloration), uv absorbers, flame retardants, reinforcing agents, plasticizers, flow improvers and/or cross-linking agents. One or more of them may be selected.

The TPU used in the present invention may be a polyether type TPU or a polyester type TPU. In the present application, "polyether TPU" refers to a TPU obtained using one or more polyether polyols as a main component (e.g., 50 wt% or more) of the long-chain polyol of reactant (b). Similarly, "polyester TPU" refers to TPU obtained using one or more polyester polyols as a major component (e.g., 50 wt% or more) of the long chain polyol of reactant (b).

The TPU products used in the present invention are also commercially available from suppliers, for example from BASF

TPU。

The raw material composition used in the present invention may include the above-mentioned TPU as a main component. However, other additives may also be included in the raw material composition. The selection of suitable additives is not particularly limited. For example, one or more additives commonly used in the fiber field, such as flame retardants, fillers, pigments, dyes, antioxidants, ultraviolet absorbers, and light stabilizers, may be used.

The crosslinking agent may be used as an additive. Any crosslinking agent may be used, but is preferably selected from the reaction product of (i) one or more polyols, (ii) one or more isocyanates, and optionally (iii) one or more other compounds. In view of the properties of the final product, i.e. the fibers, it is preferred to use one or more polyether or polyester crosslinkers. Generally, the molecular weight of the crosslinking agent is lower than the molecular weight of the TPU.

The crosslinking agent used may be a prepolymer having NCO-functional groups at the end, the functionality being from 1.5 to 3, preferably from 1.6 to 2.5, more preferably from 1.8 to 2.1. The NCO content of the prepolymer is 3 to 15% by weight, preferably 4 to 10% by weight, more preferably 4 to 8% by weight.

The polyether polyol content of the reactant (i) polyol for preparing the polyether crosslinker is at least 50 wt.%, preferably at least 80 wt.%, more preferably at least 95 wt.%. In other words, the polyether crosslinker comprises one or more structural units derived from a polyether polyol (i.e., polyether polyol units).

The selection of polyether polyol is not particularly limited. Examples thereof may include ring-opened polymers of tetrahydrofuran (polytetramethylene ether glycol, PTMEG), alkylene oxides (particularly ethylene oxide, propylene oxide and mixtures thereof) and alcohol adducts. Preferably, the polyether polyol has a number average molecular weight (Mn) of from 500g/mol to 4000g/mol, more preferably from 600g/mol to 3000g/mol, especially from 800g/mol to 2000 g/mol.

The polyester polyol content of the reactant (i) polyol for preparing the polyester crosslinker is at least 50 wt.%, preferably at least 80 wt.%, more preferably at least 95 wt.%. In other words, the polyester crosslinker comprises one or more structural units derived from a polyester polyol (i.e., polyester polyol units). Preferably, the polyester polyols have a number average molecular weight (Mn) of from 600g/mol to 4000g/mol, more preferably from 800g/mol to 3000g/mol, in particular from 1000g/mol to 3000 g/mol.

The choice of the reactant (ii) isocyanate for preparing the crosslinking agent is not particularly limited and may be selected from aromatic, aliphatic, cycloaliphatic diisocyanates. The preferred examples of reactants (a) isocyanates and (ii) isocyanates and (iii) esters for preparing the crosslinking agent described above for preparing the TPU are equally applicable. Among them, MDI is preferred.

The amount of polyether or polyester crosslinking agent is not limited, but is preferably 1 wt% or more, 3 wt% or more, or even 5 wt% or more, based on the total amount of the raw material composition. When the main ingredient (i.e., the TPU resin) is melted separately from the other ingredients (e.g., one or more crosslinking agents and/or one or more other additives), the total amount of the raw material composition is the sum of the amounts of the main ingredient and the other ingredients.

The upper limit of the amount of the crosslinking agent is not particularly limited, but in a preferred embodiment, the upper limit is 25 wt% or less, 20 wt% or less, and more preferably 15 wt% or less. The amounts are calculated based on the total amount of the raw material composition.

Non-polyether or non-polyester crosslinkers may also be used. In this case, at least 50% by weight of the reactant (i) polyol(s) for preparing the cross-linking agent is (are) selected from non-polyether polyols (i.e. polyols which are not polyether polyols) or non-polyester polyols (i.e. polyols which are not polyester polyols), such as polycaprolactone polyols and/or polycarbonate polyols.

In a preferred embodiment of the invention, the TPU is prepared from (a) PTMEG, (b) MDI and (c)1, 4-butanediol.

(B) Heat setting step

And after the TPU is melt-spun, carrying out heat setting treatment on the prepared TPU fiber.

According to the invention, the heat-setting treatment of the TPU fibers can be carried out in two ways: method A and method B. Each heat-setting method is further described below.

In method a, the fibers are first heated to shrink, then oiled, wound, and finally twisted. Specifically, as shown in fig. 2, the fiber is contracted immediately after passing through a heat pipe 5 and being heated by hot air (the air temperature reaches about 160 ℃ to 170 ℃), and the contracted threadline is oiled by a tanker 7 (nozzle) and then wound on a bobbin 9. Next, the fibers are twisted on the twister 11. Wherein the shrinking, oiling and winding can be done on one piece of equipment, the twisting can be done on another piece of equipment, and several processes are performed in a continuous manner (i.e. "on-line"). In this way, the internal and external quality of the spinning cake is uniform.

Optionally, the method further comprises unwinding the fiber from the reel before shrinking. The twisting of the fibers is usually performed in an S-twist or Z-twist manner to reduce friction in the subsequent braiding process. The fibers may be passed through the heat pipe at a rate of about 20-200m/min while shrinking. The fiber is heated rapidly by the heating mode of the heat pipe so as to achieve shrinkage and shaping. Specifically, the fibers may be passed through the heat pipe at a rate of about 20-200 m/min; or about 30-150 m/min; or about 40-120 m/min.

The TPU fibers treated by method a have a boiling water shrinkage of less than 2%.

In method B, the fiber is rewound, oiled, twisted and then shrunk and set, wherein the shrinking and twisting can be completed on one machine. Specifically, as shown in fig. 3, the fiber is unwound from the raw cake, oiled by an oil tanker 7 (oil nozzle), wound around a tube 9, and then twisted 11 and shrunk to be set on a setting twister. The shrinking is also accomplished by the heat pipe 5 at a temperature of about 160 c to 170 c. The fibers may be passed through the heat pipe at a rate of about 20-200m/min during shrinkage; or about 30-150 m/min; or about 40-120 m/min. As described above, the heat pipe can provide rapid and uniform heating of the fiber so that it can be shrink-set. Wherein, the unwinding and oiling can be completed on one device, and the twisting and the shrinking shaping can be completed on the other device. Twisting is usually performed in an S-twist or Z-twist manner to reduce friction in the subsequent braiding process. After heat setting, the TPU fibers can be wound up again. During this time, the fibers are optionally oiled. Like method A, method B is also performed in a continuous "on-line" manner with several steps.

The TPU fibers treated in process B likewise have a boiling water shrinkage of less than 2%.

As mentioned above, both Process A and Process B are "on-line" heat-set processes, which facilitate the industrial mass production of TPU fibers with high efficiency. In particular, methods a and B do not require multiple hot rolls on the machine, reducing the requirements on the production equipment compared to previous hot roll shrink-setting approaches. Also, hot roll shrinkage requires longer residence time of the fiber on the hot roll to complete the shrinkage, while methods a and B avoid long residence time of the fiber on the hot roll, improving production efficiency. In addition, compared with the prior mode that the spinning cakes are shrunk and shaped in a steam box, the spinning cakes obtained by the method A and the method B have uniform inner and outer quality, and the problem of uneven inner and outer layer quality of the spinning cakes is solved. More importantly, the TPU fibers treated by process a and process B have lower shrinkage and higher strength than the TPU fibers treated by the hot roll and steam box shrink setting method disclosed in the' 473 application.

It will be understood by those skilled in the art that the winding and/or unwinding steps in methods a and B are not necessary, and their use or omission may be determined by those skilled in the art as desired. In addition, it will be understood by those skilled in the art that oiling is for the purpose of reducing friction and dispersing static electricity, and the use or omission thereof may be decided by those skilled in the art as needed.

TPU fibers having a Denier Per Filament (DPF) of 3 to 50 produced according to the present invention have a boiling water shrinkage of less than 2%. It has a strength higher than 2 cN/dtex. The elongation at break is less than 120%. The TPU fibers produced according to the present invention can have a denier per filament of from 3 to 50, preferably from 5 to 30, and more preferably from 6 to 20 denier per filament.

The properties of the TPU fibers produced according to the invention make them useful for producing fabrics, in particular fabrics for shoe uppers, shoe laces, sports apparel (e.g., sports short or long sleeved tops, sports shorts or pants, wind jackets, sports underwear, etc.), seat mesh, watch straps, and the like. Fabrics made using TPU fibers produced according to the present invention have boiling water shrinkage of less than 10%, preferably less than 5%.

The invention combines the high-speed spinning process and the heat setting process, improves the production efficiency of the TPU fiber and can reduce the production cost. In addition, the TPU fibers produced according to the invention have a boiling water shrinkage of less than 2% and the properties of the TPU fibers of the layers of the cake are close, making them suitable as the primary raw material for producing fabrics. The size, nature and feel of the fabric thus produced can be controlled during the ironing process.

Examples

Measuring and determining method

The measurement and determination methods used in this example are shown in table 1.

TABLE 1 measurement determination method

In addition, the shrinkage of the fabric was measured as follows: taking a piece of fabric with the size of 50cm x50cm as a sample; making two marks on the sample; measuring the initial distance between two marks, and determining as L₀(ii) a Ironing the sample for 15 seconds using a commercial steam ironing machine under conditions of ironing synthetic fibers; the sample is cooled to room temperature and the distance between the two marks is measured and designated as L₁(ii) a The shrinkage of the fabric was calculated as (L)₀-L₁)/L₀x 100％。

Material

The materials used in this example are as follows.

This example uses a polyether type product

SP9519 prepares fibers based on PTMEG, MDI and 1, 4-butanediol having a weight average molecular weight of 80,000 and 200,000. This product is available from BASF and has a Shore D hardness of 60-64. The Oil used was purchased from Takemoto Oil Co., Ltd&Fat Co.，Ltd)。

The fiber to be heat-set is prepared by using the apparatus shown in fig. 1. Specifically, the TPU fibers were spun from the spin pack at 230 ℃. The fibers were oiled after spinning and then continued through godets GR1, GR2, and GR3, where the temperature and speed of each godet is shown in table 2.

TABLE 2 godet temperature and speed

Next, a TPU fiber having a denier of 300de and a denier per filament of 8.3 prepared using the above method was subjected to a heat-setting test and heat-set in accordance with inventive method A and mode A of the' 473 application, respectively.

In mode A of the' 473 application, the TPU fibers to be heat-set are heated in a steam box at 80 to 110 ℃ for 60 to 120 minutes. The properties of the resulting TPU fibers are shown in table 3.

TABLE 3-TPU fiber properties for the A mode treatment in the' 473 application

According to the heat setting of the method A, the TPU fibers to be heat-set are heated in an online manner at 160-170 ℃ by using a heat pipe. The length of the heat pipe is 70-120m, and the speed of the TPU fiber to be heat-set passing through the heat pipe is 40-100 m/min. The properties of the resulting TPU fibers are shown in table 4.

TABLE 4 TPU fiber Properties treated according to inventive method A

The above tests have demonstrated that the fiber without heat setting treatment after spinning is far inferior to the fiber subjected to heat setting treatment in boiling water shrinkage and elongation at break only after the shrinkage control treatment in the spinning process. Different heat-setting methods also result in differences in the properties of the heat-set fibers. Comparing the data in tables 3 and 4, it can be seen that the TPU fibers treated by method a of the present invention are superior to the TPU fibers heat-set in mode a of' 473 in both elongation at break and boiling water shrinkage.

In addition, according to the data of the detection of the yarn winding layering in the table 3 and the table 4, the variation of the fineness of the inner layer and the outer layer of the TPU fiber subjected to the A mode heat setting of the' 473 fiber can be calculated to be as high as 22.1de, while the variation of the fineness of the inner layer and the outer layer of the TPU fiber treated by the method A is only 7.7 de. It demonstrates the large difference in the inside and outside layer properties of the a mode heat-set TPU fibers via the' 473.

It is also noteworthy that the boiling water shrinkage of the a mode heat set TPU fiber with' 473 is negative, i.e., it does not shrink but instead increases in the shrinkage test. This demonstrates that the filament coil shrinks too much during the heat-setting in the steam box-this test demonstrates the uncontrollable heat-setting in the steam box. Also, the oil content of the TPU fibers subjected to the a mode heat setting of' 473 is not higher than 0.7%. Such low oil content makes the TPU fibers susceptible to static electricity, which is not conducive to subsequent processing.

The method B of the invention can also achieve the technical effects similar to the method A, and the obtained TPU fiber is superior to the TPU fiber of the mode A heat setting of the' 473 in the elongation at break, the boiling water shrinkage and the yarn evenness.

In addition, the heat-setting method of the' 473B mode uses a method of heating the heat-set fiber by hot rollers. This heating mode requires a long residence time of the TPU fibers on the hot rolls, otherwise it is difficult to heat the fibers sufficiently. In the case of using a plurality of hot rolls, the fibers are quenched with air between the hot rolls at a low speed, which is disadvantageous for stable and continuous heat setting. Thus, its practical operability and handleability are poor. Compared with the heat setting mode, the TPU fibers treated by the method A and the method B can obtain better technical effects on elongation at break and boiling water shrinkage.

Unless otherwise specifically stated, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In addition, it will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present application; it should not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.

All references specifically cited herein are incorporated by reference in their entirety. However, citation or incorporation of such references is not to be construed as an admission that it is appropriate as prior art to the present invention.

Non-limiting embodiments of the invention include:

1. a method of producing thermoplastic polyurethane fibers comprising:

(1) melt-spinning a composition comprising a thermoplastic polyurethane resin to obtain a fiber to be heat-set; and

(2) heat setting the fiber to be heat-set, wherein the heat-setting step comprises heat-treating and twisting to form a thermoplastic polyurethane fiber,

characterized in that said heat treatment comprises heating the fiber to be heat-set at a temperature of about 160 ℃ to about 170 ℃ to shrink it.

2. The method of claim 1, wherein said heat treating is performed prior to said twisting.

3. The method of claim 1, wherein the heat treatment is performed after the twisting.

4. The method of

claim

1 or 2, wherein the heat setting step further comprises oiling.

5. The method of claim 1 wherein the melt spinning step comprises melt spinning the composition at a spin speed of about 2000-6500 m/min; or melt spinning the composition at a spin rate of about 2000-.

6. The process of any of the preceding claims, wherein the melt spinning step comprises passing the fiber to be heat-set through about 2 to about 6 godets.

7. The process of claim 6, wherein the godet roll is a hot roll.

8. A process according to claim 5 or 6, wherein the fibres to be heat-set are passed through 3 godets.

9. The method of claim 8, wherein:

(1) a first godet of the three said godets having a temperature of from about 30 ℃ to about 150 ℃; or from about 60 ℃ to about 100 ℃;

(2) a second godet of the three said godets having a temperature of from about 60 ℃ to about 200 ℃; or from about 100 ℃ to about 160 ℃; and

(3) a third godet of the three said godets having a temperature of about 30 ℃ to 150 ℃; or about 60 c to 100 c.

10. The method of claim 9, wherein:

(1) the speed of the first godet roller is about 1000-6000 m/min; or about 1000 and 4500 m/min;

(2) the speed of the second godet roller is about 2000-6000 m/min; or about 2000-4500 m/min; and

(3) the speed of the third godet roller is about 2000-6000 m/min; or about 2000-4500 m/min.

11. A method as claimed in any preceding claim, wherein said heat treatment of said fibres to be heat-set comprises passing the fibres to be heat-set through a heat pipe.

12. The method of claim 11, wherein the fiber to be heat-set is passed through the heat pipe at a speed of about 20-200 m/min; or passing through the heat pipe at a speed of 30-150 m/min; or at a speed of 40-120 m/min.

13. The method of claim 11, wherein the heat pipe residence time of the fiber to be heat set is from 0.5 to 5 seconds.

14. The method of claim 11, wherein the heat pipe has a length of about 70-120 m.

15. A process as claimed in any preceding claim, wherein the heat treatment, oiling and twisting are carried out in a continuous manner.

16. A method according to any preceding claim, further comprising winding the fibre to be heat treated into a tube.

17. A process as claimed in any preceding claim, wherein the oiling is with a spin finish.

18. The process of any of the preceding claims, further comprising unwinding the fiber to be heat-set prior to the heat-setting step.

19. A process according to any one of the preceding claims, wherein the thermoplastic polyurethane has a hardness of Shore80 a to Shore 80D, said hardness being determined according to DIN ISO 7619-1; hardness ranging from Shore 80A to Shore 74D, as determined according to DIN ISO 7619-1; or Shore 90A to Shore 70D, the hardness being determined according to DIN ISO 7619-1.

20. A process as set forth in any preceding claim wherein said thermoplastic polyurethane is the reaction product of an isocyanate or salt, a polyol, and a chain extender.

21. The process of claim 20, wherein the reaction is carried out in the presence of a catalyst and/or an adjuvant.

22. A process as claimed in claim 20 or 21 wherein the isocyanate or salt is selected from:

(1) prepared from 2, 2 '-diphenylmethane diisocyanate, 2, 4' -diphenylmethane diisocyanate, 4 '-diphenylmethane diisocyanate, 1, 5-naphthalene diisocyanate, 2, 4-toluene diisocyanate, 2, 6-toluene diisocyanate, diphenylmethane diisocyanate, 3' -dimethylbiphenyl diisocyanate, 1, 2-diphenylethane diisocyanate, p-phenylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, heptamethylene diisocyanate, octamethylene diisocyanate, 1, 5-diisocyanate-2-methylpentane, 1, 4-diisocyanate-2-ethylbutane, 1, 5-pentamethylene diisocyanate, 1, 4-tetramethylene diisocyanate, isophorone diisocyanate, 1, 3-bis (isocyanatomethyl) cyclohexane, 1, 4-cyclohexane diisocyanate, 1-methyl-2, 6-cyclohexane diisocyanate, 4 '-dicyclohexylmethane diisocyanate, 2' -dicyclohexylmethane diisocyanate, and combinations thereof;

(2) a group consisting of 2, 2 ' -diphenylmethane diisocyanate, 2, 4 ' -diphenylmethane diisocyanate, 4 ' -diphenylmethane diisocyanate, 1, 5-naphthalene diisocyanate, 2, 4-toluene diisocyanate, 2, 6-toluene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and combinations thereof;

(3) a group consisting of 2, 2 ' -diphenylmethane diisocyanate, 2, 4 ' -diphenylmethane diisocyanate, 4 ' -diphenylmethane diisocyanate, hexamethylene diisocyanate, and combinations thereof; or

(4)2, 2 ' -diphenylmethane diisocyanate, 2, 4 ' -diphenylmethane diisocyanate, 4 ' -diphenylmethane diisocyanate.

23. The method of any one of claims 20-22, wherein the polyol:

(1) selected from the group consisting of polyester polyols, polyether polyols, polycaprolactone polyols, polycarbonate polyols, and combinations thereof;

(2) selected from the group consisting of polyester polyols, polyether polyols, and combinations thereof; or

(3) Is polytetramethylene ether glycol.

24. A process as claimed in any one of claims 20 to 23, wherein the chain extender is selected from:

(1) (ii) the group consisting of ethylene glycol, 1, 2-propanediol, 1, 3-propanediol, 1, 2-pentanediol, 1, 3-pentanediol, 1, 10-decanediol, 1, 2-cyclohexanediol, 1, 3-cyclohexanediol, 1, 4-cyclohexanediol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, 1, 4-butanediol, 1, 6-hexanediol, bis (2-hydroxyethyl) hydroquinone, triols, and combinations thereof; or

(2) 1, 3-propanediol, 1, 4-butanediol, 1, 6-hexanediol, and combinations thereof.

25. The method of claim 24, wherein the triol is selected from the group consisting of 1, 2, 4-trihydroxycyclohexane, 1, 3, 5-trihydroxycyclohexane, glycerol, trimethylolpropane, and combinations thereof.

Claims

1. A method of producing thermoplastic polyurethane fibers comprising:

4. The method of claim 1 or 2, wherein the heat setting step further comprises oiling.

7. The process of claim 6, wherein the godet roll is a hot roll.

9. The method of claim 8, wherein:

10. The method of claim 9, wherein: