fiber

Abstract

The present invention relates to fibers obtainable or obtained by a process comprising the steps of: - spinning a melt comprising an aliphatic polyester, an aliphatic-aromatic polyester, and a polyhydroxyalkanoate through a hollow fiber spinning nozzle to obtain a precursor fiber; and - cooling the precursor fiber under a temperature gradient, thereby obtaining a fiber. The present invention also relates to yarns and garments made from such fibers, and to a process for preparing such fibers.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to European Patent Application No. 21196170.1, filed with the European Patent Office on September 10, 2021, the entire contents of which are incorporated herein by reference for all purposes.

[0002] Technical Field The present invention relates to fibers comprising aliphatic polyesters, aliphatic-aromatic polyesters, and polyhydroxyalkanoates, methods for preparing such fibers, and the use of such fibers in yarns or fabrics. [Background technology]

[0003] background A sustainable textile should be based on ecological, economic and social sustainability. A sustainable product should take these factors into account, from raw materials to processing, finishing, sale and recycling.

[0004] Fibers used in sustainable textiles today include, for example, natural fibers such as cotton, wool, linen, SeaCell™ (a cellulose fiber obtained from algae, produced by Smartfiber AG), recycled fibers such as recycled polyester (e.g., from polyethylene terephthalate (PET) bottles), Econyl® (recycled nylon fiber), or regenerated fibers such as Lyocell (known, for example, under the trade name Tencel™ from Lenzing) or Modal (regenerated fibers are the names for fibers prepared from natural materials such as wood by chemical processing).

[0005] However, although these fibres are used in sustainable textiles, they still suffer from various drawbacks: for example, the production of cotton and wool requires large amounts of water consumption and is associated with the use of large amounts of land, while recycled fibres, such as recycled PET, usually require large amounts of energy, water and chemicals.

[0006] It is further desirable that sustainable textiles and fibers are suitable for use under the concept of circular economy. In particular, textiles and fibers should exhibit suitable biodegradability and thus be able to be used in biological cycles, for example under cradle-to-cradle designs, by not generating non-degradable waste. When textile products are recovered at the end of their life cycle and subjected to industrial composting, a beneficial introduction of fibers or textiles into biological cycles is achieved. This produces biomass and biogas (CH4, CO2, water), which can be directly fed into the biological cycle.

[0007] Thus, there is a continuing need for fibers which specifically address ecological requirements, and it is therefore an object of the present invention to provide such fibers. Summary of the Invention

[0008] overview This object is achieved by fibres, yarns, garments and methods having the features of the independent claims.

[0009] In a first aspect, the present invention provides a method for producing a method for treating a pulmonary circulation disorder comprising: - spinning a melt comprising an aliphatic polyester, an aliphatic-aromatic polyester, and a polyhydroxyalkanoate through a hollow fiber spinning nozzle to obtain a precursor fiber; and - cooling the precursor fiber under a temperature gradient, thereby obtaining a fiber. The present invention relates to a fiber obtainable or obtained by a process comprising the steps of:

[0010] In a second aspect, the present invention relates to a fiber made from a blend comprising an aliphatic polyester, an aliphatic-aromatic polyester, and a polyhydroxyalkanoate, the fiber includes two types of sections in the longitudinal direction, one type of section being a thicker section (thicker portion) and the other type of section being a thinner section (thinner portion), the thicker section and the thinner section extending perpendicular to the longitudinal direction of the fiber, the vertical extent of the thicker section being greater than the vertical extent of the thinner section; At least a portion of the thicker portion has a cavity, and at least a portion of the thinner portion has a dense structure.

[0011] In a third aspect, the invention relates to hollow fibers made from a blend comprising an aliphatic polyester, an aliphatic-aromatic polyester, and a polyhydroxyalkanoate.

[0012] In a fourth aspect, the present invention relates to a yarn comprising the fiber of the present invention.

[0013] In a fifth aspect, the present invention relates to a textile comprising the fiber of the invention or the yarn of the invention.

[0014] In a sixth aspect, the present invention provides a method for producing a composition comprising the steps of: - spinning a melt comprising an aliphatic polyester, an aliphatic-aromatic polyester, and a polyhydroxyalkanoate through a hollow fiber spinning nozzle to obtain a precursor fiber; and - cooling the precursor fiber under a temperature gradient, thereby obtaining a fiber. The present invention also relates to a method for preparing the fibers of the present invention, comprising:

[0015] In a seventh aspect, the present invention relates to the use of a melt comprising an aliphatic polyester, an aliphatic-aromatic polyester, and a polyhydroxyalkanoate, for the preparation of a fiber as defined herein.

[0016] In an eighth aspect, the present invention relates to the use of a melt comprising an aliphatic polyester, an aliphatic-aromatic polyester, and a polyhydroxyalkanoate for the preparation of hollow fibers.

[0017] In a ninth aspect, the invention relates to a blend comprising an aliphatic polyester, an aliphatic-aromatic polyester, and a polyhydroxyalkanoate.

[0018] In a tenth aspect, the present invention relates to the use of a mixture comprising an aliphatic polyester, an aliphatic-aromatic polyester, and a polyhydroxyalkanoate, for the preparation of a fiber as defined herein.

[0019] In an eleventh aspect, the present invention relates to the use of a mixture comprising an aliphatic polyester, an aliphatic-aromatic polyester, and a polyhydroxyalkanoate for the preparation of hollow fibers. [Brief description of the drawings]

[0020] The present invention will be better understood by reference to the detailed description when considered in conjunction with the non-limiting examples and drawings in which: [Figure 1] FIG. 1 shows a schematic diagram of a melt spinning apparatus for preparing fibers according to an embodiment of the invention, in which precursor fibers are cooled under a temperature gradient. [Diagram 2] FIG 2A shows a photograph of a melt spinning apparatus that can be used to prepare fibers according to embodiments of the invention. The oval highlights the air-cooled assembly of the melt spinning apparatus. FIG 2B shows a photograph of another melt spinning apparatus that can be used to prepare fibers according to embodiments of the invention. Again, the oval highlights the air-cooled assembly of the melt spinning apparatus. [Diagram 3] FIG. 3 shows a schematic diagram of a fiber manufacturing process including further processing of the fibers after the processing line according to an embodiment of the present invention. [Figure 4]Figure 4 shows various fibers traditionally used for the manufacture of textiles. From left to right, the fibers shown are coarse wool, fine wool, alpaca, cashmere, silk, linen, cotton, and polyester. [Figure 5A] 5A shows a schematic diagram of a fiber according to an embodiment of the invention, which includes a thicker portion having a cavity and a thinner portion having a dense or condensed structure. [Figure 5B] FIG. 5B shows an electron microscope photograph of a fiber according to an embodiment of the invention having thicker and thinner portions (relative to each other). [Figure 5C] FIG. 5C shows an electron microscope photograph of a thin section disposed between two thick sections of a fiber according to an embodiment of the invention. [Figure 5D] FIG. 5D shows an electron microscope image of a cross section of a fiber according to an embodiment of the invention, showing cavities. [Figure 5E] 5E shows additional electron micrographs of cross-sections of fibers according to embodiments of the invention. The three micrographs in the top panel and the center micrograph in the bottom panel show cross-sections of thicker sections of fibers that contain cavities. The left and right micrographs in the bottom panel show cross-sections of thinner sections of fibers that have a compact or condensed structure. [Figure 5F] FIG. 5F shows an electron microscope photograph of a cross section of the outer cavity wall of a fiber according to an embodiment of the invention. [Figure 6A] FIG. 6A shows the moisture absorption test setup for (from left to right) cotton fibers, fibers according to an embodiment of the invention (obtained by using cooling under a temperature gradient), polyester fibers, and polybutylene succinate fibers. [Figure 6B] Figure 6B shows the moisture absorption test setup for (from left to right) cotton fibers immediately prior to testing, a fiber according to an embodiment of the invention (obtained by using cooling under a temperature gradient), a polyester (PES) fiber, and a polybutylene succinate (PBS) fiber. Four fiber balls are simultaneously immersed approximately 1 cm into the coloring liquid. The time measurement starts from the moment the fiber balls are immersed in the liquid. [Figure 6C]FIG. 6C shows the test approximately 13 seconds after the fiber ball was immersed in the liquid. [Figure 6D] 6D shows that dyeing is observed for cotton fibers and fibers according to embodiments of the invention (obtained by using cooling under a temperature gradient) approximately 3.5 minutes after immersion of the fiber ball in the liquid. In general, dyeing of cotton fibers and fibers according to embodiments of the invention can be observed after 2 minutes of immersion of the fiber ball in the liquid. [Figure 6E] Figure 6E shows that 6 minutes after the fiber ball was immersed in the liquid, the liquid-immersed cotton fiber and the fiber according to the embodiment of the invention (obtained by using cooling under a temperature gradient) are partially significantly swollen, while the PBS fiber ball shows very little staining in the center. [Figure 6F] Figure 6F shows the test just before stopping the fiber ball after 15 minutes of immersion in liquid. It can be seen that the fiber ball (second from the left) containing fibers according to an embodiment of the invention (obtained by using cooling under a temperature gradient) has substantially maintained its shape. The fiber ball according to an embodiment of the invention (second from the left) has migrated liquid higher than the cotton fiber ball (first on the left). At the bottom of the cotton fiber ball, clumping due to swelling can be observed. [Figure 7] FIG. 7 shows the drying of fiber balls in a Petri dish at 40° C. for 10 minutes. [Figure 8] FIG. 8 shows a schematic diagram of a hollow fiber according to an embodiment of the invention having a continuous cavity. [Figure 9] Figure 9A shows a photograph of a shirt made with fibers (particularly yarns made from fibers) according to an embodiment of the invention obtained using cooling under a temperature gradient. Figure 9B shows another view of a shirt made with fibers (particularly yarns made from fibers) according to an embodiment of the invention. Figure 9C shows a further view of a shirt made with fibers (particularly yarns made from fibers) according to an embodiment of the invention obtained. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Detailed Description As stated above, in a first aspect, the present invention provides a method for producing a composition comprising the steps of: - spinning a melt comprising an aliphatic polyester, an aliphatic-aromatic polyester, and a polyhydroxyalkanoate through a hollow fiber spinning nozzle to obtain a precursor fiber; and - cooling the precursor fiber under a temperature gradient, thereby obtaining a fiber. The present invention relates to a fiber obtainable or obtained by a process comprising the steps of:

[0022] Surprisingly, it has been found that the fibers obtainable or obtainable by the method comprising spinning a melt comprising an aliphatic polyester, an aliphatic-aromatic polyester, and a polyhydroxyalkanoate through a hollow fiber spinning nozzle to obtain a precursor fiber and cooling the precursor fiber under a temperature gradient to obtain a fiber have comparable or better moisture absorption properties compared to cotton (see Example 3 herein below). In other words, the fibers of the invention have a similar hydrophilicity to cotton. Surprisingly, it has also been found that the time required to dry the fibers of the invention is significantly shorter than cotton (see Example 3). Thus, the fibers of the invention can be used, for example, to produce surfaces, in particular textiles, which are able to absorb moisture and to dry again with less energy than cotton. Thus, as an advantage, the fibers of the invention have comparable or better properties in terms of hydrophilicity and drying behavior compared to cotton. However, as a major further advantage, at the same time, the preparation of the fibers requires much less water and land use than cotton (see Example 4). As a further advantage, the production of the fibers can be carried out without the use of harmful substances, such as, for example, antimony (see Example 2). Furthermore, by using aliphatic polyesters, aliphatic-aromatic polyesters, and polyhydroxyalkanoates, fibers can be obtained that are biodegradable and also meet the European harmonized standard EN 13432, and thus can be processed in industrial composting plants. The fibers of the present invention can be used as textile fibers, for example, to manufacture clothing such as shirts (see Example 5 and Figures 9A, 9B, and 9C). Here, it was found that such clothing is biodegradable enough to completely decompose / degrade within just two weeks after being put into organic waste.In this connection, it is noted that various products, such as, for example, plates and foils as well as fibers, comprising one or more of aliphatic polyesters, aliphatic-aromatic polyesters, and / or polyhydroxyalkanoates, have been described, for example, in EP 3 626 767, WO 2010 / 034689, WO 2010 / 034711, WO 2015 / 169660, EP 1 966 419, EP 2 984 138, CN 103668540, CN 103668541, WO 2014 / 173055, and CN 104120502. However, these documents only describe conventional processing methods for these polymers.

[0023] The term "precursor fiber" as used herein generally refers to a fiber that occurs as an intermediate during the manufacturing process of the present invention after exiting the hollow fiber spinning nozzle and upon cooling under a temperature gradient. The (final) fiber of the present invention that is obtainable or obtained by the process, especially after cooling under a temperature gradient, is generally referred to simply as "fiber."

[0024] Surprisingly, it has also been found that the fibers obtainable or obtained by the method comprising spinning a melt comprising an aliphatic polyester, an aliphatic-aromatic polyester, and a polyhydroxyalkanoate through a hollow fiber spinning nozzle to obtain a precursor fiber, and cooling the precursor fiber under a temperature gradient to obtain a fiber, have a specific structure comprising a thick section and a thin section, the thick section may have a cavity, and the thin section may have a compact or condensed structure.The present invention therefore also relates to a fiber made from a mixture comprising an aliphatic polyester, an aliphatic-aromatic polyester, and a polyhydroxyalkanoate, the fiber comprises two types of sections in the longitudinal direction, one type of section being a thick section and the other type of section being a thin section, the thick section and the thin section extending perpendicularly to the longitudinal direction of the fiber, the vertical extension of the thick section being greater than the vertical extension of the thin section; at least some of the thick sections have a cavity, and at least some of the thin sections have a compact structure. The fibers may also be referred to as segmented fibers or segmented hollow fibers, since they include thick portions with cavities and thin portions with dense structures. Fibers according to embodiments of the invention having thick portions with cavities and thin portions are shown, for example, in Figures 5A and 5B (thick portion 15, thin portion 17, and cavities 19). Without wishing to be bound by theory, it is believed herein that this structure, including thick portions with cavities and thin portions with dense structures, is due to partial fusion of adjacent hollow fiber portions upon cooling of the precursor fiber under a temperature gradient.

[0025] As used herein, the term "void" generally refers to a hollow space present in the cross section of a fiber, for example, as shown in the center of the upper and lower panels of Figures 5A, 5B, 5D, 5E, and 5F. The cavity may be filled with a gas, for example, air. The term "compact structure", which may also be referred to as "condensed structure", generally refers to the fiber material being present in a substantially dense or condensed form, especially when compared to the cavity of the fiber (such as the structure shown on the left and right sides of the lower panel of Figure 5E). However, the term "compact structure" or "condensed structure" may also include that the respective structure contains pores, for example, as shown on the left and right sides of the lower panel of Figure 5E.

[0026] The melt for spinning fibers can be produced using any method for producing a melt for spinning fibers known to those skilled in the art. Illustratively, the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate can be mixed in an unmolten state, for example, by mixing granules of the polymer, optionally with one or more further additives. Optionally, the polymer and, if present, the additives can be dried before mixing and preparing the melt. The mixture can then be heated to above the melting point of the polymer to prepare the melt. Illustratively, the mixing and heating can be carried out in an extruder. Illustratively, the melt can be heated to a temperature of 250° C. The melt is then passed through a hollow fiber spinning nozzle. Illustratively, an extruder can be used to pass the melt through the hollow fiber spinning nozzle. Any hollow fiber spinning nozzle generally known in the art can be used, for example, the hollow fiber spinning nozzle described in EP 2 112 256, the entire contents of which are incorporated herein by reference. A melt comprising an aliphatic polyester, an aliphatic-aromatic polyester, and a polyhydroxyalkanoate is spun through a hollow fiber spinneret to obtain a hot precursor fiber, which is cooled under a temperature gradient to obtain a fiber.

[0027] The temperature gradient may be generated by any suitable means / devices capable of generating a temperature gradient for use in the present invention. The temperature gradient may be generated, for example, by one or more temperature control elements. By way of example, the temperature gradient may be generated by locating and / or operating a temperature control element in or near the spinning apparatus. Apparatus for melt spinning is generally known to those skilled in the art (see also, for example, Figures 2A and 2B, which show a conventional melt spinning apparatus). The temperature control element may be a heating and / or cooling element capable of either actively or passively exerting a heating or cooling effect on the precursor fiber. Such a temperature control element may, for example, allow one selected side / surface region of the precursor fiber to be cooled, such that one side / surface region of the precursor fiber is, for example, cooled, while another surface region (typically the surface region opposite the selected side / surface region) is heated or at least maintained at the temperature present after exiting the nozzle of the spinning apparatus. An illustrative but non-limiting example of a temperature control element that is a cooling element is an air-cooled assembly. As an example of a temperature gradient, the precursor fiber may emerge from the spinning nozzle at a temperature of about 250° C. A temperature gradient may then be generated, for example, by air-cooling the precursor fiber from one side. Thus, air-cooling may be provided by providing an air flow to the precursor fiber from only one side of the precursor fiber in a direction substantially perpendicular to the longitudinal direction of the precursor fiber by using an air-cooling assembly disposed on one side of the precursor fiber (see, for example, FIG. 1, precursor fiber 3, and air flow 7). The air used for air-cooling may have a temperature of ambient temperature, preferably room temperature, more preferably +20° C.+ / -5° C.

[0028] The one or more temperature control elements can be arranged to generate a temperature gradient in a direction substantially perpendicular to the longitudinal direction of the precursor fiber. It is equally suitable that the one or more temperature control elements are arranged to generate a temperature gradient in a direction substantially parallel to the cross-section of the precursor fiber.

[0029] Preferably, the one or more temperature control elements are arranged such that the temperature of one outer surface of the precursor fiber is lower than the temperature of the opposite outer surface. In particular, the one or more temperature control elements may be arranged such that the precursor fiber is cooled from one side. Preferably, the cooling is performed by air cooling. Preferably, the air cooling may be performed by providing an air flow from one side to the precursor fiber in a direction substantially perpendicular to the longitudinal direction of the precursor fiber by using an air cooling assembly arranged on one side of the precursor fiber (see, for example, FIG. 1, precursor fiber 3 and air flow 7). The air flow from the opposite side to the one side may be prevented by turning off the air cooling assembly arranged on the opposite side of the precursor fiber. The air flow from the opposite side to the one side may also be prevented by arranging one or more baffles between the precursor fiber and the air cooling assembly arranged on the opposite side of the precursor fiber (see, for example, FIG. 1, precursor fiber 3, baffle 5, and air flow 9). Therefore, by placing one or more baffles between the precursor fiber and an air-cooling assembly located on the opposite side thereof, i.e., the air-cooling assembly located on the opposite side to the side where the air flow is supplied to the precursor fiber, air flow from the opposite side onto the precursor fiber can be prevented over at least a portion of the precursor fiber along its longitudinal direction.

[0030] The term "aliphatic polyester" as used herein generally refers to polyesters that are typically synthesized through the condensation polymerization of an aliphatic diol and an aliphatic dicarboxylic acid or anhydride thereof. By way of example, an aliphatic polyester as used herein is an aliphatic C2-C 20 Dicarboxylic acids and aliphatic C2-C 12The aliphatic polyester may include an aliphatic diol. Preferably, the aliphatic diol is an aliphatic C2-C8 diol. More preferably, the aliphatic diol is an aliphatic C2-C6 diol. Even more preferably, the aliphatic diol is an aliphatic C3 diol or an aliphatic C4 diol. The aliphatic diol used in the aliphatic polyester may include, for example, ethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol. Preferably, the aliphatic diol is 1,3-propanediol or 1,4-butanediol. More preferably, the aliphatic diol is 1,4-butanediol. Preferably, the aliphatic dicarboxylic acid is an aliphatic C2-C 12 dicarboxylic acid. More preferably, the aliphatic dicarboxylic acid is an aliphatic C2-C8 dicarboxylic acid, and even more preferably, an aliphatic C4 dicarboxylic acid. The aliphatic dicarboxylic acid used in the aliphatic polyester may include, by way of example, oxalic acid, malonic acid, succinic acid, glutaric acid, and adipic acid. Preferably, the aliphatic dicarboxylic acid is malonic acid or succinic acid. More preferably, the aliphatic dicarboxylic acid is succinic acid. Optionally, the dicarboxylic acid is an aliphatic C2-C 12 In the case of dicarboxylic acids, aliphatic polyesters are C2-C 12 Additional aliphatic C6-C different from dicarboxylic acids 20 It may further comprise a dicarboxylic acid. Any aliphatic C6-C 12 Dicarboxylic acids may include, by way of example, adipic acid, suberic acid, azelaic acid, sebacic acid, brassylic acid, and arachidonic acid. Preferably, any aliphatic C6-C 12 Dicarboxylic acids may include adipic acid, suberic acid, azelaic acid, sebacic acid and brassylic acid. Any aliphatic C2-C 12The dicarboxylic acid may be present in the aliphatic polyester in a proportion of 0 to 10 mol % based on 100 mol % of the total amount of aliphatic dicarboxylic acids in the aliphatic polyester. Optionally, the aliphatic polyester may further include a chain extender and / or a branching agent. The optional chain extender and / or branching agent may include, by way of example, polyfunctional isocyanates, isocyanurates, oxazolines, carboxylic anhydrides such as maleic anhydride, epoxides (especially epoxy-containing poly(meth)acrylates), at least trihydric alcohols, and at least tribasic carboxylic acids. The optional chain extender and / or branching agent may be present in the aliphatic polyester in a proportion of 0 to 1 % by weight based on 100 % by weight of the total amount of aliphatic dicarboxylic acids and aliphatic diols. The term "aliphatic polyester" may also include a mixture of two or more different aliphatic polyesters. The aliphatic polyester may have a number average molecular weight (Mn) in the range of 2,500 to 150,000 g / mol, preferably 5,000 to 100,000 g / mol, more preferably 7,500 to 75,000 g / mol, even more preferably 10,000 to 65,000 g / mol, and even more preferably 12,000 to 60,000 g / mol. The aliphatic polyester may have a weight average molecular weight (Mw) in the range of 5,000 to 300,000 g / mol, preferably 10,000 to 250,000 g / mol, more preferably 20,000 to 220,000 g / mol, even more preferably 50,000 to 200,000 g / mol, and even more preferably 60,000 to 190,000 g / mol. The aliphatic polyester may have a polydispersity index (i.e., the ratio of weight average molecular weight to number average molecular weight (Mw / Mn)) in the range of 1 to 6, preferably 1 to 4, more preferably 1.0 to 3.0, even more preferably 1.2 to 2.0, and even more preferably 1.4 to 1.8.

[0031] Examples of aliphatic polyesters that can be used in the present invention include aliphatic polyesters selected from the group consisting of polybutylene succinate (PBS), polyethylene oxalate, polyethylene malonate, polyethylene succinate, polypropylene oxalate, polypropylene malonate, polypropylene succinate, polybutylene oxalate, polybutylene malonate, polybutylene succinate-co-adipate (PBSA), polybutylene succinate-co-azelate (PBSAz), polybutylene succinate-co-brassyllate (PBSBr), and any combination thereof. The aliphatic polyesters can be preferably selected from the group consisting of polybutylene succinate (PBS), polybutylene succinate-co-adipate (PBSA), polybutylene succinate-co-azelate (PBSAz), polybutylene succinate-co-brassyllate (PBSBr), and any combination thereof. In one preferred embodiment, the aliphatic polyester is polybutylene succinate. The term "polybutylene succinate" as used herein refers in particular to the condensation product of the aliphatic dicarboxylic acid succinic acid and the aliphatic diol 1,4-butanediol. The aliphatic polyesters polybutylene succinate (PBS) and polybutylene succinate-co-adipate (PBSA) are commercially available, for example, from Showa Polymer under the trade name Blanche® and from Mitsubishi under the trade name GSPIa®. Aliphatic polyesters, particularly polybutylene succinate (PBS), can be obtained from renewable resources or from fossil resources. Preferably, aliphatic polyesters from renewable resources are used. More preferably, bio-based polybutylene succinate (PBS) produced from bio-based succinic acid and 1,4-butanediol, for example, commercially available from Mitsubishi Chemical under the trade name BioPBS® FZ71, can be used. Preferably, the aliphatic polyester is biodegradable. In particular, polybutylene succinate (PBS) is a biodegradable aliphatic polyester.

[0032] Preferably, the fiber contains the aliphatic polyester in an amount of 30 to 70% by weight based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate. More preferably, the fiber contains the aliphatic polyester in an amount of 35 to 65% by weight based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate. Even more preferably, the fiber contains the aliphatic polyester in an amount of 40 to 60% by weight or 42 to 62% by weight based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate. Even more preferably, the fiber contains the aliphatic polyester in an amount of 45 to 55% by weight based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate. In particular, these ranges are applicable when the aliphatic polyester is polybutylene succinate. In a preferred embodiment, the fibers contain 52% by weight polybutylene succinate, based on 100% by weight of the combined total of polybutylene succinate, aliphatic-aromatic polyester, and polyhydroxyalkanoate.

[0033] The term "aliphatic-aromatic polyester" as used herein generally refers to a polyester that is typically synthesized from an aliphatic diol, an aliphatic dicarboxylic acid, and an aromatic dicarboxylic acid. Illustratively, an aliphatic-aromatic polyester is a polyester that is typically synthesized from an aliphatic C2-C 20 Dicarboxylic acids, aromatic dicarboxylic acids, and aliphatic C2-C 12The aliphatic diol may include an aliphatic C2-C8 diol. More preferably, the aliphatic diol is an aliphatic C2-C6 diol. More preferably, the aliphatic diol is an aliphatic C3 diol or an aliphatic C4 diol. The aliphatic diol used in the aliphatic-aromatic polyester may include, by way of example, ethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol. Preferably, the aliphatic diol is 1,3-propanediol or 1,4-butanediol. More preferably, the aliphatic diol is 1,4-butanediol. Preferably, the aliphatic dicarboxylic acid is an aliphatic C2-C 12 More preferably, the aliphatic dicarboxylic acid is an aliphatic C4-C 10dicarboxylic acid, more preferably aliphatic C6 dicarboxylic acid. Aliphatic dicarboxylic acids used in the aliphatic-aromatic polyester may include, by way of example, glutaric acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, brassylic acid, suberic acid, and itaconic acid. Preferably, the aliphatic dicarboxylic acid is adipic acid, azelaic acid, or sebacic acid. More preferably, the aliphatic dicarboxylic acid is adipic acid. Preferably, the aromatic dicarboxylic acid is terephthalic acid. The aromatic dicarboxylic acid, particularly terephthalic acid, may be present in the aliphatic-aromatic polyester in an amount of, for example, 30 to 70 mol%, preferably 40 to 60 mol%, more preferably 40 to 55 mol%, based on 100 mol% of the total amount of the aliphatic dicarboxylic acid and the aromatic dicarboxylic acid. Optionally, the aliphatic polyester may further include a chain extender and / or a branching agent. The optional chain extender may illustratively include a di- or polyfunctional isocyanate, preferably hexamethylene diisocyanate. The optional branching agent may illustratively include trimethylolpropane, pentaerythritol, and preferably glycerol. The optional chain extender and / or branching agent may be present in the aliphatic polyester in a proportion of 0-1% by weight, based on 100% by weight of the total amount of the aliphatic dicarboxylic acid, aromatic dicarboxylic acid, and aliphatic diol. The term "aliphatic-aromatic polyester" may also include a mixture of two or more different aliphatic-aromatic polyesters. The aliphatic-aromatic polyester may have a number average molecular weight (Mn) in the range of 1,000-500,000 g / mol, preferably 5,000-300,000 g / mol, more preferably 5,000-100,000 g / mol, even more preferably 10,000-75,000 g / mol, and even more preferably 15,000-50,000 g / mol. The aliphatic-aromatic polyester may have a weight average molecular weight (Mw) in the range of 10,000 to 500,000 g / mol, preferably 20,000 to 400,000 g / mol, more preferably 30,000 to 300,000 g / mol, and even more preferably 60,000 to 200,000 g / mol.The aliphatic-aromatic polyesters may have a polydispersity index (i.e., the ratio of weight average molecular weight to number average molecular weight (Mw / Mn)) in the range of 1 to 6, preferably 2 to 4, more preferably 1.0 to 3.0, even more preferably 1.2 to 2.0, and even more preferably 1.4 to 1.8.

[0034] The aliphatic-aromatic polyester that can be used in the present invention can include, but is not limited to, an aliphatic-aromatic polyester selected from the group consisting of polybutylene adipate terephthalate (PBAT), polybutylene succinate terephthalate (PBST), polybutylene sebacate terephthalate (PBSeT), and any combination thereof. In one preferred embodiment, the aliphatic-aromatic polyester is polybutylene adipate terephthalate (PBAT). The term "polybutylene adipate terephthalate" as used herein refers to an aliphatic-aromatic polyester that includes an aliphatic dicarboxylic acid, adipic acid, an aromatic dicarboxylic acid, terephthalic acid, and an aliphatic diol, 1,4-butanediol. The aliphatic-aromatic polyester, particularly polybutylene adipate terephthalate (PBAT), can be obtained from renewable or fossil resources. Preferably, an aliphatic-aromatic polyester from a renewable resource is used. Polybutylene adipate terephthalate (PBAT) is commercially available, for example, as Ecoflex® by BASF, e.g. Ecoflex® F Blend C1200 or Ecoflex® FBX 7011, or as Bionolle® by Showa Denko. Preferably, the aliphatic-aromatic polyester is biodegradable. In particular, polybutylene adipate terephthalate (PBAT) is a biodegradable aliphatic-aromatic polyester.

[0035] Preferably, the fiber contains the aliphatic-aromatic polyester in an amount of 10 to 60% by weight based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate. More preferably, the fiber contains the aliphatic-aromatic polyester in an amount of 20 to 50% by weight based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate. Even more preferably, the fiber contains the aliphatic-aromatic polyester in an amount of 25 to 40% by weight or 26 to 46% by weight based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate. Even more preferably, the fiber contains the aliphatic-aromatic polyester in an amount of 30 to 40% by weight based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate. These ranges are particularly applicable when the aliphatic-aromatic polyester is polybutylene adipate terephthalate (PBAT). In a preferred embodiment, the fiber comprises 36% by weight of polybutylene adipate terephthalate (PBAT) based on 100% by weight of the total amount of aliphatic polyester, polybutylene adipate terephthalate (PBAT), and polyhydroxyalkanoate.

[0036] The term "polyhydroxyalkanoates" as used herein generally refers to polyesters from hydroxyalkane carboxylic acid monomers. Polyhydroxyalkanoates can be produced by a number of microorganisms, including through bacterial fermentation of sugars or lipids. Preferably, the hydroxyalkane carboxylic acids are C4-C 18 Preferably the polyhydroxyalkanoate comprises a monomer unit having the formula (I): TIFF2024533421000001.tif8128In the formula, R is the formula C n H 2n+1where n is an integer from 1 to 15, preferably from 1 to 6. In some embodiments, the polyhydroxyalkanoate is a homopolymer. In some preferred embodiments, the polyhydroxyalkanoate is a copolymer. When the polyhydroxyalkanoate is a copolymer, the copolymer may contain two different monomer units of formula (I). The term "polyhydroxyalkanoate" may also include a mixture of two or more different polyhydroxyalkanoates. The polyhydroxyalkanoate may have a weight average molecular weight (Mw) in the range of 70,000 to 1,000,000 g / mol, preferably 100,000 to 1,000,000 g / mol, more preferably 300,000 to 600,000 g / mol.

[0037] Illustrative examples of polyhydroxyalkanoates that can be used in the present disclosure include polyhydroxyalkanoates selected from the group consisting of polyhydroxybutyrate, polyhydroxyvalerate, polyhydroxybutyrate-co-hydroxyvalerate, polyhydroxybutyrate-co-hydroxyhexanoate, and any combination thereof. Preferably, the polyhydroxyalkanoate is selected from the group consisting of poly-3-hydroxybutyrate (P3HB), poly-4-hydroxybutyrate (P4HB), poly-3-hydroxyvalerate (PHV), poly(3-hydroxybutyrate-co-4-hydroxybutyrate), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), and any combination thereof. More preferably, the polyhydroxyalkanoate is selected from the group consisting of poly-3-hydroxybutyrate (PHB). TIFF2024533421000002.tif30128, Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) TIFF2024533421000003.tif28128, and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) TIFF2024533421000004.tif28128, and any combination thereof. More preferably, the polyhydroxyalkanoate is polyhydroxybutyrate-co-hydroxyhexanoate. In a highly preferred embodiment, the polyalkoxyalkanoate is poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH). Preferably, the molar ratio m:n in the above structural formula is 95:5 to 85:15, more preferably 90:10 to 88:12. Preferably, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) is used, each having a molar ratio of 3-hydroxyhexanoic acid of 5 to 15 mol%, preferably 7 to 13 mol%, more preferably 10 to 13 mol%, based on 100 mol% of the total amount of monomers in poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH). Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) is commercially available, for example, by P&G or Kaneka. Polyhydroxyalkanoates, in particular poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), may be obtained from renewable or fossil resources. Preferably, polyhydroxyalkanoates derived from renewable resources are used. More preferably, for example, bio-derived poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) commercially available from Kaneka under the trade name AONILEX X 151 A can be used. Preferably, the polyhydroxyalkanoate is biodegradable. In particular, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) is a biodegradable polyhydroxyalkanoate.

[0038] Preferably, the fiber contains polyhydroxyalkanoate in an amount of 1 to 25% by weight based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate. More preferably, the fiber contains polyhydroxyalkanoate in an amount of 2 to 22% by weight based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate. Even more preferably, the fiber contains polyhydroxyalkanoate in an amount of 3 to 20% by weight based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate. Even more preferably, the fiber contains polyhydroxyalkanoate in an amount of 3 to 18% by weight based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate. Even more preferably, the fiber contains polyhydroxyalkanoate in an amount of 5-15% by weight, based on 100% by weight of the total amount of aliphatic polyester, aliphatic-aromatic polyester, and polyhydroxyalkanoate. In particular, these ranges are applicable when the polyhydroxyalkanoate is polyhydroxybutyrate-co-hydroxyhexanoate, preferably poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH). Preferably, when the polyhydroxyalkanoate is polyhydroxybutyrate-co-hydroxyhexanoate, preferably poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), the fiber comprises no more than 20% by weight, more preferably no more than 18% by weight, of polyhydroxybutyrate-co-hydroxyhexanoate, preferably poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxybutyrate-co-hydroxyhexanoate, preferably poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH).If the proportion of polyhydroxybutyrate-co-hydroxyhexanoate, preferably poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), exceeds 18% by weight, it may be difficult to achieve the EN 13432 standard for biodegradability without prior or industrial composting, and even more so if it exceeds 20% by weight. In a preferred embodiment, the fiber comprises 12% by weight of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), based on 100% by weight of the total amount of polybutylene succinate, polybutylene adipate terephthalate, and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH).

[0039] In one highly preferred embodiment, the aliphatic polyester is polybutylene succinate (PBS), the aliphatic-aromatic polyester is polybutylene adipate terephthalate (PBAT), and the polyalkoxyalkanoate is poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH). Thus, in one highly preferred embodiment, the fiber comprises polybutylene succinate (PBS), polybutylene adipate terephthalate (PBAT), and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH).

[0040] The ranges for the amounts of aliphatic polyester, aliphatic-aromatic polyester, and polyhydroxyalkanoate may also be combined with each other. Thus, by way of example, the fiber may contain aliphatic polyester in an amount of 42-62% by weight, preferably 45-55% by weight, the fiber may contain aliphatic-aromatic polyester in an amount of 26-46% by weight, preferably 30-40% by weight, and the fiber may contain polyhydroxyalkanoate in an amount of 2-22% by weight, preferably 3-20% by weight, more preferably 3-18% by weight, based on the total amount of aliphatic polyester, aliphatic-aromatic polyester, and polyhydroxyalkanoate of 100% by weight, respectively. A person skilled in the art will easily select suitable amounts of one or more polymers within the ranges provided herein, such that the total amount of aliphatic polyester, aliphatic-aromatic polyester, and polyhydroxyalkanoate does not exceed 100% by weight. In particular, these ranges are applicable when the aliphatic polyester is polybutylene succinate, the aliphatic-aromatic polyester is polybutylene adipate terephthalate, and the polyhydroxyalkanoate is polyhydroxybutyrate-co-hydroxyhexanoate, preferably poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH). In a highly preferred embodiment, the fibers comprise 52% by weight of polybutylene succinate, 36% by weight of polybutylene adipate terephthalate, and 12% by weight of polyhydroxybutyrate-co-hydroxyhexanoate, preferably poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), based on 100% by weight of the total amount of polybutylene succinate, polybutylene adipate terephthalate, and polyhydroxybutyrate-co-hydroxyhexanoate, preferably poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), respectively.

[0041] Preferably, the fiber is a textile fiber. As used herein, the term "textile fiber" generally refers to a fiber suitable for making a textile. By way of non-limiting example, the textile fiber may be suitable for preparing a yarn, a fabric, or a textile surface.

[0042] Optionally, the fiber may further include at least one additive (one or more additives). For example, the fiber may include at least one additive (or one or more additives) generally known to be used in textile fibers. The optional additives may include, but are not limited to, additives such as flame retardants, matting agents, authentication markers (e.g., fluorescent markers), antimicrobial agents, fillers, and any combination thereof.

[0043] Preferably, the fibers further comprise a flame retardant, such as a phosphate. As used herein, the term "phosphate" refers to a flame retardant such as [H2PO4] - , [HPO4] 2- , and [PO4] 3- Preferably, the cation is ammonium [NH4]. +Thus, in a preferred embodiment, the flame retardant is selected from the group consisting of ammonium dihydrogen phosphate ([NH4][H2PO4]), diammonium hydrogen phosphate ([NH4]2[HPO4]), triammonium phosphate ([NH4]3[PO4]), and any combination thereof. More preferably, the flame retardant is selected from the group consisting of ammonium dihydrogen phosphate ([NH4][H2PO4]), diammonium hydrogen phosphate ([NH4]2[HPO4]), and any combination thereof. More preferably, the flame retardant is ammonium dihydrogen phosphate ([NH4][H2PO4]) or diammonium hydrogen phosphate ([NH4]2[HPO4]). Even more preferably, the flame retardant is diammonium hydrogen phosphate ([NH4]2[HPO4]). Alternatively, or in addition, the flame retardant may be a polyphosphate. A "polyphosphate" is a salt or ester of a polymeric oxyanion formed from tetrahedral PO4 (phosphate) structural units bonded together by sharing oxygen atoms. Preferably, when the flame retardant is a polyphosphate, the flame retardant is ammonium polyphosphate. Without wishing to be bound by theory, it is believed herein that adding a phosphate or polyphosphate flame retardant, particularly diammonium hydrogen phosphate ([NH4]2[HPO4]), can promote partial fusion of adjacent hollow fiber sections during cooling of the precursor fiber under a temperature gradient, which can contribute to obtaining the fiber structure described herein, including a thick section with a cavity and a thin section with a dense structure.

[0044] The fibers may contain the flame retardant in an amount of 0.01 to 5 wt. % relative to 100 wt. % of the total weight of the fibers. Preferably, the fibers contain the flame retardant in an amount of 0.1 to 4 wt. % relative to 100 wt. % of the total weight of the fibers. More preferably, the fibers contain the flame retardant in an amount of 0.2 to 3 wt. % relative to 100 wt. % of the total weight of the fibers. Even more preferably, the fibers contain the flame retardant in an amount of 0.3 to 3 wt. % relative to 100 wt. % of the total weight of the fibers. Even more preferably, the fibers contain the flame retardant in an amount of 0.3 to 2 wt. % relative to 100 wt. % of the total weight of the fibers. In particular, the above ranges are applicable when the flame retardant is a phosphate or polyphosphate, preferably when the flame retardant is diammonium hydrogen phosphate ([NH4]2[HPO4]).

[0045] Optionally, the fibers may also include a matting agent. Any matting agent known to those skilled in the art may be used, such as typical matting agents used in fibers. By way of example, the matting agent may be zinc sulfide.

[0046] Optionally, the fibres may (also) comprise a marker suitable for authentication. As an illustrative, non-limiting example, the marker suitable for authentication may be a fluorescent marker. The fluorescence of the fibres can be detected by a suitable device and used to authenticate the fibres. For example, fluorescent markers available from Polysecure, Freiburg im Breisgau, Germany can be used. Markers suitable for authentication are generally only used in small amounts that do not usually alter the properties of the fibre. Typically, the amount of markers suitable for authentication in the fibres is in the ppb (parts per billion) range.

[0047] Optionally, the fibers may also include an antimicrobial agent. Any antimicrobial agent known to those skilled in the art suitable for use in fibers may be used. As an illustrative, non-limiting example, the antimicrobial agent may be zinc encapsulated in polyethylene terephthalate. Such a matting agent is commercially available, for example, under the trade name SMARTZINC 213 PET Hot Melt from Smartpolymer GmbH, Rudolstadt, Germany.

[0048] Optionally, the fibers may (also) comprise a filler. Any filler known to those skilled in the art suitable for use in fibers may be used, with biodegradable fillers being preferred. By way of example, the (biodegradable) filler may be or may comprise lignin.

[0049] A person skilled in the art will readily select suitable amounts of additives to be included in the fibers. By way of example, the fibers may include a total amount of additives of 15% or less by weight based on 100% of the total weight of the fibers. The fibers may include a total amount of additives of 10% or less by weight based on 100% of the total weight of the fibers. Preferably, the fibers include a total amount of additives of 7% or less by weight based on 100% of the total weight of the fibers. More preferably, the fibers include a total amount of additives of 5% or less by weight based on 100% of the total weight of the fibers. Even more preferably, the fibers include a total amount of additives of 4% or less by weight based on 100% of the total weight of the fibers. Even more preferably, the fibers include a total amount of additives of 3-4% by weight based on 100% of the total weight of the fibers. To achieve fiber stiffness useful for textile fibers, the fibers preferably include a total amount of additives of 7% or less by weight, more preferably 3-4% by weight, based on 100% of the total weight of the fibers.

[0050] The fineness is not particularly limited. For example, any fineness generally used in the textile industry can be applied. As an example, the fineness can be 0.5 to 8 den. Preferably, the fineness is 0.8 to 6 den. More preferably, the fineness is 0.9 to 3 den. Even more preferably, the fineness is 1.0 to 2 den. Even more preferably, the fineness is 1.0 to 1.5 den. Even more preferably, the fineness is 1.1 to 1.2 den.

[0051] The fibers may be staple fibers. The term "staple fibers" as used herein generally refers to fibers of discontinuous length. The staple length is not particularly limited. For example, any stable length commonly used in the textile industry may be applied. Thus, by way of example, the fibers may have a staple length of 2 to 80 mm. Preferably, the fibers have a staple length of 5 to 70 mm. More preferably, the fibers have a staple length of 10 to 60 mm. Even more preferably, the fibers have a staple length of 15 to 50 mm. Even more preferably, the fibers have a staple length of 20 to 40 mm. Even more preferably, the fibers have a staple length of 22 to 35 mm. Even more preferably, the fibers have a staple length of 25 to 32 mm. The term "staple length" generally refers to the average length of the fibers in a sample.

[0052] A fiber can be a filament. The term "filament" or "filament fiber" generally refers to a fiber of virtually unlimited length. Thus, the term "filament" or "filament fiber" generally refers to a continuous fiber.

[0053] Preferably, the fibers are biodegradable. More preferably, the fibers have biodegradability according to EN 13432. Thus, a fiber may be considered to be biodegradable according to EN 13432 if it has a degree of biodegradation equal to at least 90% of the degree of biodegradation according to DIN EN 13432 after a given period of time. The general effect of biodegradability is that the fiber decomposes within an appropriate and verifiable period of time. Decomposition may be caused enzymatically, hydrolytically, oxidatively and / or through the action of electromagnetic radiation, e.g. UV radiation, and may be mainly due to the action of microorganisms such as bacteria, yeasts, fungi and algae. Biodegradability may be quantified, for example, by mixing the fibers with compost and storing it for a certain period of time. For example, during composting, CO2-free air may be flowed through the mature compost and the mature compost may be subjected to a defined temperature program. Biodegradability can be defined, for example, as the percentage biodegradability, which is the ratio of the net CO2 released from a sample (after subtracting the CO2 released from the compost without the sample) to the maximum amount of CO2 that can be released from the sample (determined from the carbon content of the sample). Biodegradable fibers typically show obvious signs of decomposition, such as fungal growth, cracks and holes, after only a few days of composting. Other methods for determining biodegradability are described, for example, in ASTM D 5338 and ASTM D 6400.

[0054] Preferably, the thicker and thinner sections of the fiber are arranged in an alternating pattern along the length of the fiber. The lengths of the thicker and thinner sections along the length of the fiber may be irregular.

[0055] In the fiber, the extent of the cavities in the longitudinal direction of the fiber may be greater than the extent of the cavities in a direction perpendicular to the longitudinal direction of the fiber. The cavities may have an irregular perimeter (e.g., as shown in FIG. 5E). In particular, the perimeter may be irregular in a plane taken in a direction perpendicular to the longitudinal direction of the fiber.

[0056] Preferably the fibers are crimped fibers.

[0057] The present invention also relates to hollow fibers made from a mixture comprising an aliphatic polyester and an aliphatic-aromatic polyester and a polyhydroxyalkanoate. The term "hollow fiber" as used herein and known in the art generally refers to a fiber having one or more, particularly one, continuous cavity in its cross section (see, for example, FIG. 8 for an illustration of a hollow fiber 21 having a continuous cavity 23). The one or more cavities may be filled with, for example, air. Such hollow fibers may be prepared by any method known in the art suitable for preparing hollow fibers.

[0058] By way of example, the hollow fibers may be obtainable or obtainable by a method comprising a step of spinning a melt comprising an aliphatic polyester, an aliphatic-aromatic polyester, and a polyhydroxyalkanoate through a hollow fiber spinning nozzle to obtain a precursor fiber. By way of example, as already mentioned herein above, the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate may be mixed in an unmolten state, for example by mixing granules of the polymer, optionally with one or more further additives, and the mixture may be heated to above the melting point of the polymer. By way of example, the mixing and heating may be carried out in an extruder. The melt is then passed through a hollow fiber spinning nozzle. By way of example, an extruder may be used to pass the melt through the hollow fiber spinning nozzle. Any hollow fiber spinning nozzle generally known in the art may be used, for example the hollow fiber spinning nozzle described in EP 2 112 256, the entire contents of which are incorporated herein by reference. A melt containing an aliphatic polyester, an aliphatic-aromatic polyester, and a polyhydroxyalkanoate is spun through a hollow fiber spinning nozzle to obtain a hot precursor fiber. However, after passing through the spinning nozzle, the precursor fiber is cooled using conventional means to obtain a conventional hollow fiber. Cooling using conventional means may, for example, assume that the precursor fiber is cooled under a substantially uniform temperature distribution throughout the fiber. Thus, the temperature gradients described herein above may be substantially avoided. The substantially uniform temperature distribution may be produced by one or more temperature control elements. By way of example, the uniform temperature distribution may be produced by locating and / or operating a temperature control element in or near the spinning device in a suitable manner. The temperature control element may be a heating and / or cooling element (e.g., an air-cooled assembly) that can provide a heating or cooling effect on the precursor fiber either actively or passively. Such a temperature control element may cool each side / surface region of the precursor fiber such that the temperature distribution on each side / surface region is substantially uniform.A person skilled in the art will easily arrange one or more temperature control elements in a suitable manner to achieve a uniform temperature distribution across the precursor fiber. For example, the precursor fiber may be cooled using air cooling. Preferably, air cooling may be performed by providing air flow to the precursor fiber from both sides in a direction substantially perpendicular to the longitudinal direction of the precursor fiber by using air cooling assemblies arranged on both sides of the precursor fiber. By way of example only, the provision of air flow to the precursor fiber from both sides can be achieved by removing the baffle 5 between the precursor fiber 3 and the air flow 9 shown in FIG. 1.

[0059] The hollow fibers may be further defined as described herein for any fiber. Thus, by way of example, the hollow fibers may be further defined as described herein for any fiber in relation to the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate, the ratio of the polymers, and / or the at least one additive.

[0060] Optionally, any of the fibers described herein may be subjected to fiber post-treatment, for example, using a fiber post-treatment line. Post-treatment may include steps conventionally used in the treatment of fibers, such as reeding, suction construction, soaking, drafting, stretching, steaming, reviving, crimping, drying, and / or staple cutting.

[0061] The present invention also relates to yarns comprising the fibers described herein. Any type of yarn may be considered. As non-exemplary examples, the yarns may be spun, carded or combed, knitted, open-end, decorative, filament, or textured. The yarns may be prepared from the fibers described herein by any method suitable for preparing yarns. Methods for preparing yarns are generally known and readily selected by the skilled artisan.

[0062] The present invention also relates to a textile surface comprising the fibers described herein. The present invention also relates to a textile surface comprising a yarn, the yarn comprising the fibers described herein. By way of illustrative and non-limiting example, the textile surface may be selected from the group consisting of fabrics, knitted fabrics, and nonwoven fabrics. The fibers or yarns comprising the fibers may also be used to prepare fleeces.

[0063] The present invention also relates to a textile comprising the fibers described herein. The present invention also relates to a textile comprising a yarn, the yarn comprising the fibers described herein. The textile may be a garment. As illustrative and non-limiting examples, the garment may be selected from the group consisting of shirts, polo shirts, trousers, jackets, underwear, socks, coats, shoes and shoelaces. In particular, the garment may be a shirt or a polo shirt, preferably a shirt. The textile may be a home textile. As illustrative and non-limiting examples, the home textile may be selected from the group consisting of curtains, rugs, blankets, bed sheets, duvets, duvet covers, cushions, cushion covers and towels.

[0064] The present invention relates to - spinning a melt comprising an aliphatic polyester, an aliphatic-aromatic polyester, and a polyhydroxyalkanoate through a hollow fiber spinning nozzle to obtain a precursor fiber; and - cooling the precursor fiber under a temperature gradient, thereby obtaining a fiber. The present invention also relates to a method for preparing the fiber of the present invention, comprising: The fiber may be further defined as described herein.

[0065] Preferably, the temperature gradient is created by cooling the precursor fiber from one side.

[0066] Preferably, the cooling is by air cooling.

[0067] Preferably, the melt contains the aliphatic polyester in an amount of 30 to 70% by weight based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate. More preferably, the melt contains the aliphatic polyester in an amount of 35 to 65% by weight based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate. Even more preferably, the melt contains the aliphatic polyester in an amount of 40 to 60% by weight or 42 to 62% by weight based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate. Even more preferably, the melt contains the aliphatic polyester in an amount of 45 to 55% by weight based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate. In particular, these ranges are applicable when the aliphatic polyester is polybutylene succinate. In a preferred embodiment, the melt contains 52% by weight of polybutylene succinate, based on 100% by weight of the combined total of polybutylene succinate, aliphatic-aromatic polyester, and polyhydroxyalkanoate.

[0068] Preferably, the melt contains the aliphatic-aromatic polyester in an amount of 10 to 60% by weight, based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate. More preferably, the melt contains the aliphatic-aromatic polyester in an amount of 20 to 50% by weight, based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate. Even more preferably, the melt contains the aliphatic-aromatic polyester in an amount of 25 to 40% by weight or 26 to 46% by weight, based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate. Even more preferably, the melt contains the aliphatic-aromatic polyester in an amount of 30 to 40% by weight, based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate. In particular, these ranges are applicable when the aliphatic-aromatic polyester is polybutylene adipate terephthalate (PBAT). In a preferred embodiment, the melt contains 36% by weight of polybutylene adipate terephthalate (PBAT) for a total of 100% by weight of the aliphatic polyester, polybutylene adipate terephthalate (PBAT) and polyhydroxyalkanoate.

[0069] Preferably, the melt contains polyhydroxyalkanoate in an amount of 1 to 25% by weight, based on 100% by weight of the total amount of aliphatic polyester, aliphatic-aromatic polyester, and polyhydroxyalkanoate. More preferably, the melt contains polyhydroxyalkanoate in an amount of 2 to 22% by weight, based on 100% by weight of the total amount of aliphatic polyester, aliphatic-aromatic polyester, and polyhydroxyalkanoate. Even more preferably, the melt contains polyhydroxyalkanoate in an amount of 3 to 20% by weight, based on 100% by weight of the total amount of aliphatic polyester, aliphatic-aromatic polyester, and polyhydroxyalkanoate. Even more preferably, the melt contains polyhydroxyalkanoate in an amount of 3 to 18% by weight, based on 100% by weight of the total amount of aliphatic polyester, aliphatic-aromatic polyester, and polyhydroxyalkanoate. More preferably, the melt contains the polyhydroxyalkanoate in an amount of 5 to 15% by weight, based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate. In particular, these ranges are applicable when the polyhydroxyalkanoate is polyhydroxybutyrate-co-hydroxyhexanoate, preferably poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH). Preferably, when the polyhydroxyalkanoate is polyhydroxybutyrate-co-hydroxyhexanoate, preferably poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), the melt comprises not more than 20% by weight, more preferably not more than 18% by weight, of polyhydroxybutyrate-co-hydroxyhexanoate, preferably poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester and the polyhydroxybutyrate-co-hydroxyhexanoate, preferably poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH).

[0070] The ranges for the amounts of aliphatic polyester, aliphatic-aromatic polyester, and polyhydroxyalkanoate may also be combined with each other. Thus, by way of example, the melt may contain aliphatic polyester in an amount of 42-62% by weight, preferably 45-55% by weight, the melt may contain aliphatic-aromatic polyester in an amount of 26-46% by weight, preferably 30-40% by weight, and the melt may contain polyhydroxybutyrate in an amount of 2-22% by weight, preferably 3-20% by weight, more preferably 3-18% by weight, based on 100% by weight of the total amount of aliphatic polyester, aliphatic-aromatic polyester, and polyhydroxyalkanoate, respectively. A person skilled in the art will easily select suitable amounts of one or more polymers within the ranges provided herein, such that the total amount of aliphatic polyester, aliphatic-aromatic polyester, and polyhydroxyalkanoate does not exceed 100% by weight. In particular, these ranges are applicable when the aliphatic polyester is polybutylene succinate, the aliphatic-aromatic polyester is polybutylene adipate terephthalate, and the polyhydroxyalkanoate is polyhydroxybutyrate-co-hydroxyhexanoate, preferably poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH). In a highly preferred embodiment, the melt comprises 52% by weight of polybutylene succinate, 36% by weight of polybutylene adipate terephthalate, 12% by weight of polyhydroxybutyrate-co-hydroxyhexanoate, preferably poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), based on 100% by weight of the total amount of polybutylene succinate, polybutylene adipate terephthalate and polyhydroxybutyrate-co-hydroxyhexanoate, preferably poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), respectively.

[0071] Optionally, the melt may further include at least one additive. For example, the melt may include at least one additive generally known to be used in textile fibers. The optional additive may include, but is not limited to, an additive selected from the group consisting of a flame retardant, a matting agent, an authentication marker (e.g., a fluorescent marker), an antimicrobial agent, a filler, and any combination thereof.

[0072] Preferably, the melt further comprises a flame retardant. More preferably, the flame retardant is a phosphate (phosphate salt or phosphoric acid ester). In a preferred embodiment, the flame retardant is selected from the group consisting of ammonium dihydrogen phosphate ([NH4][H2PO4]), diammonium hydrogen phosphate ([NH4]2[HPO4]), triammonium phosphate ([NH4]3[PO4]), and any combination thereof. More preferably, the flame retardant is selected from the group consisting of ammonium dihydrogen phosphate ([NH4][H2PO4]), diammonium hydrogen phosphate ([NH4]2[HPO4]), and any combination thereof. More preferably, the flame retardant is ammonium dihydrogen phosphate ([NH4][H2PO4]) or diammonium hydrogen phosphate ([NH4]2[HPO4]). Even more preferably, the flame retardant is diammonium hydrogen phosphate ([NH4]2[HPO4]). Alternatively or additionally, the flame retardant may be a polyphosphate. Preferably, when the flame retardant is a polyphosphate, the flame retardant is an ammonium polyphosphate.

[0073] The melt may contain a flame retardant in an amount of 0.01 to 5 wt% relative to 100 wt% of the total weight of the melt. Preferably, the melt contains a flame retardant in an amount of 0.1 to 4 wt% relative to 100 wt% of the total weight of the melt. More preferably, the melt contains a flame retardant in an amount of 0.2 to 3 wt% relative to 100 wt% of the total weight of the melt. Even more preferably, the melt contains a flame retardant in an amount of 0.3 to 3 wt% relative to 100 wt% of the total weight of the melt. Even more preferably, the melt contains a flame retardant in an amount of 0.3 to 2 wt% relative to 100 wt% of the total weight of the melt. In particular, the above ranges are applicable when the flame retardant is a phosphate or polyphosphate, preferably when the flame retardant is diammonium hydrogen phosphate ([NH4]2[HPO4]).

[0074] A person skilled in the art will easily select a suitable amount of additives to be included in the melt. By way of example, the melt may include additives in a total amount of 15% by weight or less, based on 100% by weight of the total melt. The melt may include additives in a total amount of 10% by weight or less, based on 100% by weight of the total melt. Preferably, the melt includes additives in a total amount of 7% by weight or less, based on 100% by weight of the total melt. More preferably, the melt includes additives in a total amount of 5% by weight or less, based on 100% by weight of the total melt. Even more preferably, the melt includes additives in a total amount of 4% by weight or less, based on 100% by weight of the total melt. Even more preferably, the melt includes additives in a total amount of 3-4% by weight, based on 100% by weight of the total melt. To achieve fiber stiffness useful for textile fibers, the melt preferably includes additives in a total amount of 7% by weight or less, more preferably 3-4% by weight, based on 100% by weight of the total melt.

[0075] The fibers may be prepared as staple fibers.

[0076] The fibers may be prepared as filaments.

[0077] The present invention also relates to the use of melts comprising aliphatic polyesters, aliphatic-aromatic polyesters, and polyhydroxyalkanoates for the preparation of fibers as defined herein.

[0078] The present invention also relates to the use of melts comprising aliphatic polyesters, aliphatic-aromatic polyesters, and polyhydroxyalkanoates for the preparation of hollow fibers.

[0079] The present invention also relates to mixtures comprising an aliphatic polyester, an aliphatic-aromatic polyester, and a polyhydroxyalkanoate. Such mixtures can be used, for example, for the preparation of the fibers according to the invention.

[0080] The aliphatic polyester, aliphatic-aromatic polyester, and polyhydroxyalkanoate contained in the mixture may be further defined as described herein, in particular as described herein for any fiber. In one highly preferred embodiment, the aliphatic polyester is polybutylene succinate (PBS), the aliphatic-aromatic polyester is polybutylene adipate terephthalate (PBAT), and the polyalkoxyalkanoate is poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH). Thus, the present invention also relates to a mixture comprising polybutylene succinate (PBS), polybutylene adipate terephthalate (PBAT), and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH).

[0081] In some embodiments, the mixture consists essentially of an aliphatic polyester, an aliphatic-aromatic polyester, and a polyhydroxyalkanoate. In some embodiments, the mixture consists essentially of polybutylene succinate (PBS), polybutylene adipate terephthalate (PBAT), and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH). In some embodiments, the mixture consists of an aliphatic polyester, an aliphatic-aromatic polyester, and a polyhydroxyalkanoate. In some embodiments, the mixture consists of polybutylene succinate (PBS), polybutylene adipate terephthalate (PBAT), and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH).

[0082] In the mixture, the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate may be in the form of particles. Exemplary particles that may be used in the mixture may be selected from the group consisting of granules, pellets, extrudates, beads, prills, and any combination thereof. Preferably, the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate are in the form of granules. In a highly preferred embodiment, the mixture comprises polybutylene succinate (PBS), polybutylene adipate terephthalate (PBAT), and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) in the form of granules. The present invention also relates to granules comprising polybutylene succinate (PBS), polybutylene adipate terephthalate (PBAT), and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH). To prepare fibers, the mixture comprising particles of the polymers may be heated above the melting point of the polymers. In some embodiments, the mixture can thus be in the form of a melt, which can be subjected to spinning as described herein.

[0083] Preferably, the mixture contains the aliphatic polyester in an amount of 30 to 70% by weight based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate. More preferably, the mixture contains the aliphatic polyester in an amount of 35 to 65% by weight based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate. Even more preferably, the mixture contains the aliphatic polyester in an amount of 40 to 60% by weight or 42 to 62% by weight based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate. Even more preferably, the mixture contains the aliphatic polyester in an amount of 45 to 55% by weight based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate. In particular, these ranges are applicable when the aliphatic polyester is polybutylene succinate. In a preferred embodiment, the mixture comprises 52% by weight of polybutylene succinate, based on 100% by weight of the combined amount of polybutylene succinate, aliphatic-aromatic polyester and polyhydroxyalkanoate.

[0084] Preferably, the mixture contains the aliphatic-aromatic polyester in an amount of 10 to 60% by weight, based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate. More preferably, the mixture contains the aliphatic-aromatic polyester in an amount of 20 to 50% by weight, based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate. Even more preferably, the mixture contains the aliphatic-aromatic polyester in an amount of 25 to 40% by weight or 26 to 46% by weight, based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate. Even more preferably, the mixture contains the aliphatic-aromatic polyester in an amount of 30 to 40% by weight, based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate. In particular, these ranges are applicable when the aliphatic-aromatic polyester is polybutylene adipate terephthalate (PBAT). In a preferred embodiment, the mixture comprises 36% by weight of polybutylene adipate terephthalate (PBAT) based on 100% by weight of the total amount of aliphatic polyester, polybutylene adipate terephthalate (PBAT) and polyhydroxyalkanoate.

[0085] Preferably, the mixture contains polyhydroxyalkanoate in an amount of 1 to 25% by weight based on 100% by weight of the total amount of aliphatic polyester, aliphatic-aromatic polyester, and polyhydroxyalkanoate. More preferably, the mixture contains polyhydroxyalkanoate in an amount of 2 to 22% by weight based on 100% by weight of the total amount of aliphatic polyester, aliphatic-aromatic polyester, and polyhydroxyalkanoate. Even more preferably, the mixture contains polyhydroxyalkanoate in an amount of 3 to 20% by weight based on 100% by weight of the total amount of aliphatic polyester, aliphatic-aromatic polyester, and polyhydroxyalkanoate. Even more preferably, the mixture contains polyhydroxyalkanoate in an amount of 3 to 18% by weight based on 100% by weight of the total amount of aliphatic polyester, aliphatic-aromatic polyester, and polyhydroxyalkanoate. More preferably, the mixture contains the polyhydroxyalkanoate in an amount of 5 to 15% by weight based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate. In particular, these ranges are applicable when the polyhydroxyalkanoate is polyhydroxybutyrate-co-hydroxyhexanoate, preferably poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH). Preferably, when the polyhydroxyalkanoate is polyhydroxybutyrate-co-hydroxyhexanoate, preferably poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), the melt comprises not more than 20% by weight, more preferably not more than 18% by weight, of polyhydroxybutyrate-co-hydroxyhexanoate, preferably poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester and the polyhydroxybutyrate-co-hydroxyhexanoate, preferably poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH).

[0086] The ranges for the amounts of aliphatic polyester, aliphatic-aromatic polyester, and polyhydroxyalkanoate may also be combined with each other. Thus, by way of example, the melt may contain aliphatic polyester in an amount of 42-62% by weight, preferably 45-55% by weight, the melt may contain aliphatic-aromatic polyester in an amount of 26-46% by weight, preferably 30-40% by weight, and the melt may contain polyhydroxybutyrate in an amount of 2-22% by weight, preferably 3-20% by weight, more preferably 3-18% by weight, based on 100% by weight of the total amount of aliphatic polyester, aliphatic-aromatic polyester, and polyhydroxyalkanoate, respectively. A person skilled in the art will easily select suitable amounts of one or more polymers within the ranges provided herein, such that the total amount of aliphatic polyester, aliphatic-aromatic polyester, and polyhydroxyalkanoate does not exceed 100% by weight. In particular, these ranges are applicable when the aliphatic polyester is polybutylene succinate, the aliphatic-aromatic polyester is polybutylene adipate terephthalate, and the polyhydroxyalkanoate is polyhydroxybutyrate-co-hydroxyhexanoate, preferably poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH). In a highly preferred embodiment, the mixture comprises 52% by weight of polybutylene succinate, 36% by weight of polybutylene adipate terephthalate, and 12% by weight of polyhydroxybutyrate-co-hydroxyhexanoate, preferably poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), based on a total of 100% by weight of polybutylene succinate, polybutylene adipate terephthalate, and polyhydroxybutyrate-co-hydroxyhexanoate, preferably poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), respectively.

[0087] Optionally, the mixture may further include at least one additive. For example, the mixture may include at least one additive generally known to be used in textile fibers. The optional additive may include, but is not limited to, an additive selected from the group consisting of flame retardants, matting agents, authentication markers (e.g., fluorescent markers), antimicrobial agents, fillers, and any combination thereof.

[0088] Preferably, the mixture further comprises a flame retardant. More preferably, the flame retardant is a phosphate. In a preferred embodiment, the flame retardant is selected from the group consisting of ammonium dihydrogen phosphate ([NH4][H2PO4]), diammonium hydrogen phosphate ([NH4]2[HPO4]), triammonium phosphate ([NH4]3[PO4]), and any combination thereof. More preferably, the flame retardant is selected from the group consisting of ammonium dihydrogen phosphate ([NH4][H2PO4]), diammonium hydrogen phosphate ([NH4]2[HPO4]), and any combination thereof. More preferably, the flame retardant is ammonium dihydrogen phosphate ([NH4][H2PO4]) or diammonium hydrogen phosphate ([NH4]2[HPO4]). Even more preferably, the flame retardant is diammonium hydrogen phosphate ([NH4]2[HPO4]). Alternatively or additionally, the flame retardant may be a polyphosphate. Preferably, when the flame retardant is a polyphosphate, the flame retardant is an ammonium polyphosphate.

[0089] The mixture may contain the flame retardant in an amount of 0.01 to 5 wt.% relative to 100 wt.% of the total weight of the melt. Preferably, the mixture contains the flame retardant in an amount of 0.1 to 4 wt.% relative to 100 wt.% of the total weight of the mixture. More preferably, the mixture contains the flame retardant in an amount of 0.2 to 3 wt.% relative to 100 wt.% of the total weight of the mixture. Even more preferably, the mixture contains the flame retardant in an amount of 0.3 to 3 wt.% relative to 100 wt.% of the total weight of the mixture. Even more preferably, the mixture contains the flame retardant in an amount of 0.3 to 2 wt.% relative to 100 wt.% of the total weight of the mixture. In particular, the above ranges are applicable when the flame retardant is a phosphate or polyphosphate, preferably when the flame retardant is diammonium hydrogen phosphate ([NH4]2[HPO4]).

[0090] A person skilled in the art will easily select suitable amounts of additives to be included in the mixture. By way of example, the mixture may include additives in a total amount of 15% by weight or less, based on 100% by weight of the total weight of the melt. The mixture may include additives in a total amount of 10% by weight or less, based on 100% by weight of the total weight of the melt. Preferably, the mixture includes additives in a total amount of 7% by weight or less, based on 100% by weight of the total weight of the mixture. More preferably, the mixture includes additives in a total amount of 5% by weight or less, based on 100% by weight of the total weight of the mixture. Even more preferably, the mixture includes additives in a total amount of 4% by weight or less, based on 100% by weight of the total weight of the mixture. Even more preferably, the mixture includes additives in a total amount of 3-4% by weight, based on 100% by weight of the total weight of the mixture. To achieve fiber stiffness useful for textile fibers, the mixture includes additives in a total amount of preferably 7% by weight or less, more preferably 3-4% by weight, based on 100% by weight of the total weight of the mixture.

[0091] The present invention also relates to the use of a mixture comprising an aliphatic polyester, an aliphatic-aromatic polyester, and a polyhydroxyalkanoate for preparing a fiber as defined herein.

[0092] The present invention also relates to the use of a mixture comprising an aliphatic polyester, an aliphatic-aromatic polyester, and a polyhydroxyalkanoate for the preparation of hollow fibers.

[0093] It should be noted that, as used herein, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a reagent" includes one or more of such different reagents, and reference to "the method" includes reference to equivalent steps and methods known to those of skill in the art that may be modified in connection with or substituted for the methods described herein.

[0094] Unless otherwise indicated, the term "at least" preceding a series of elements is to be understood to refer to each element in the series. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. Such equivalents are intended to be encompassed by this invention.

[0095] The term "and / or" wherever used in this specification includes the meaning of "and", "or" and "any or any other combination of the elements connected by that term".

[0096] The terms "less than" and "greater than" do not include a specified numerical value. For example, "less than 20" means less than the numerical value indicated. Similarly, "greater than" means greater than the numerical value indicated, for example, greater than 80% means greater than the numerical value indicated.

[0097] Throughout this specification and the claims which follow, the word "comprise" and variations such as "comprises" and "comprising" are understood to imply the inclusion of a stated integer or step or group of entities or steps, but not the exclusion of any other entities or steps or groups of entities or steps, unless the context indicates otherwise. As used herein, the term "comprising" can be replaced with the terms "containing" or "including," and sometimes with the term "having" when used herein.

[0098] As used herein, "consisting of" excludes any element, step, or ingredient not specified in the claim element. As used herein, "consisting essentially of" does not exclude materials or steps that do not materially affect the basic and novel characteristics of the claim. In any instance herein, any of the terms "comprising," "consisting essentially of," and "consisting of" may be replaced with either of the other two terms.

[0099] The term "including" means "including but not limited to." "Including" and "including but not limited to" are used interchangeably.

[0100] As used herein, the term "about" is understood to mean that there may be up to 5% or up to 10% variation of the given value in each value or range (pH, concentration, percentage, molar concentration, time, etc.) For example, if a formulation contains about 5 mg / ml of a compound, this is understood to mean that the formulation may have between 4.5 and 5.5 mg / ml of it.

[0101] It is to be understood that this invention is not limited to the particular methodology, protocols, materials, reagents, and substances, etc. described herein, as such may vary. The terminology used herein is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the present invention, which is defined solely by the claims.

[0102] All documents cited throughout the text of this specification, whether supra or infra, including all patents, patent applications, scientific literature, manuals, etc., are incorporated herein by reference in their entirety. Nothing in this specification is to be construed as an admission that the present invention is not entitled to antedate such disclosure by virtue of prior invention. In the event that material incorporated by reference contradicts or is inconsistent with the present specification, the present specification will control over such material.

[0103] The contents of all publications and patent documents cited herein are incorporated by reference in their entirety.

[0104] The present invention and its advantages will be better understood from the following examples, which are provided for illustrative purposes only and are not intended to limit the scope of the invention in any way. EXAMPLES

[0105] Example 1: Preparation of fibers according to embodiments of the present invention For the preparation of fibers according to embodiments of the present invention, the following components (Polymer I, Polymer II, Polymer III, and additive masterbatch) were used: Polymer I: Polybutylene succinate (PBS, Mitsubishi Chemical Bio PBS FZ71, biologically derived) Polymer II: Polybutylene adipate terephthalate (PBAT, BASF ECOFLEX PBAT) Polymer III: Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PBHB, Kaneka AONILEX X151A, biologically derived) Masterbatch: The masterbatch contains additives in the amounts shown in Table 1 below.

[0106] [Table 1]

[0107] Fibers according to embodiments of the invention were prepared using a Fourne Pilot Melt Spintester (Fourne Maschinenbau GmbH, Alfter-Impekoven, Germany) equipped with a post-module allowing side flow of masterbatch additives, a hollow fiber spinning nozzle (e.g., the hollow fiber spinning nozzle described in EP2112256 B1 can be used), and a fiber post-treatment line. The Fourne Pilot Melt Spintester is shown in FIG. 2B. Further external processing was performed on the fiber post-treatment line using the steps of a reed, an air intake structure, a dip tank, draft system I, a stretching tank, draft system II, steam treatment, draft system III, activation rollers, crimping, drying, and a staple cutter. Alternatively, a different melt spinning apparatus can be used; an example of an alternative melt spinning apparatus is shown in FIG. 2A.

[0108] Polymer I (15,600 g, polybutylene succinate (PBS)), polymer II (10,800 g, polybutylene adipate terephthalate (PBAT)) and polymer III (3,600 g, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH)) were added to the melt spin tester as granules. Additionally, 1.650 kg of powdered masterbatch (additive) was added to the module via a simple screw feeder to allow side flow. The moisture content was about 0.1 wt.%. Polymers I, II and III as well as the masterbatch (additive) were dried in a vacuum drying cabinet at 60 °C for 24 h before addition.

[0109] The following process parameters were used: Flow rate: 2.5kg / h up to 5.12m / min tow; Processing temperature: 250℃; Distance between hollow fiber spinning nozzle and godet: 200cm; Take-off godet: 85℃ 800m / min; Godet roller 1: 80℃ 980m / min; Godet roller 2: 80℃ 1350m / min; operating an air-cooling assembly on one side of the precursor fiber to provide an air flow to the precursor fiber from said one side; and The air flow from the opposite side of the precursor fiber was prevented by providing a baffle between the air-cooling assembly and the precursor fiber, thereby stopping the air cooling on the opposite side of the precursor fiber, and thus the precursor fiber was cooled under a temperature gradient.

[0110] The melt spinning apparatus and the process for the preparation of the fibers are shown diagrammatically in FIG. 1. The melt spinning apparatus of FIG. 1 includes a hollow fiber spinning nozzle 1. A melt containing three polymers, which in this example has a processing temperature of 250° C., is spun through the hollow fiber spinning nozzle 1 using an extruder to obtain a hot precursor fiber 3. An air flow 7 is supplied to the precursor fiber 3 from the left side in a direction approximately perpendicular to the longitudinal direction of the precursor fiber 3 to cool the precursor fiber 3. The air flow 7 may be supplied by an air-cooling assembly, which is shown diagrammatically by a snowflake on the left side. In this example, the air used for the air flow 7 is at ambient temperature (about 20° C.). The air flow 9 is supplied from the right side. The air flow 9 may also be supplied by an air-cooling assembly, which is shown diagrammatically by a snowflake on the right side. A baffle 5 is disposed between the air flow 9 and the precursor fiber 3. Thus, the baffle 5 prevents the air flow 9 from the right from reaching the precursor fiber 3 over the portion of the precursor fiber 3 covered by the baffle 5. Thus, only the air flow 7 from the left side reaches the precursor fiber 3. As a result, the precursor fiber 3 is at a lower temperature on the left side, where the air flow 7 impinges on the precursor fiber 3, than on the right side, where the air flow 9 is blocked by the baffle 5. The precursor fiber 3 is therefore cooled under a temperature gradient. Cooling under a temperature gradient results in a fiber 11. The fiber 11 is then taken up by a godet roll 13.

[0111] Alternatively, instead of using a baffle, one of the two air-cooling assemblies of the melt spinning apparatus may be shut off, again so that airflow is only provided to the precursor fiber 3 from one side.

[0112] In this example, a Fourne Pilot Melt Spintester (Fourne Maschinenbau GmbH, Alfter-Impekoven, Germany) is used, as shown in Figure 2B. Alternatively, any other suitable melt spinning device can be used, such as the larger melt spinning device shown in Figure 2A. In both Figures 2A and 2B, an ellipse is drawn to indicate the air-cooled assembly with a grid.

[0113] 3 shows an extension scheme of fiber preparation and further processing of the fibers by post-treatment according to an embodiment of the present invention. As shown in FIG. 3, the fibers may be subjected to, for example, finishing, cutting, and compacting into bales.

[0114] Figure 4 shows fibers commonly used to make textiles. From left to right, the fibers are coarse wool, fine wool, alpaca, cashmere, silk, linen, cotton, and polyester.

[0115] 5A, 5B, 5C, 5D, 5E, and 5F show fibers according to embodiments of the invention, for example, produced using cooling of precursor fibers under a temperature gradient as described in this Example 1. FIG. 5A shows a schematic diagram of a fiber according to an embodiment of the invention. Fiber 11 includes a thick section 15 and a thin section 17. The thick section includes a cavity 19. FIG. 5B shows an electron micrograph of a fiber according to an embodiment of the invention. The thick and thin sections can be distinguished. FIG. 5C shows an electron micrograph of a fiber according to an embodiment of the invention. The micrograph shows a thin section of the fiber, located between two thick sections. The fiber has a substantially smooth outer surface. FIG. 5D shows an electron micrograph of a cross section of a fiber according to an embodiment of the invention. The cavity is visible. FIG. 5E shows a further electron micrograph of a cross section of a fiber according to an embodiment of the invention. The three micrographs in the top panel and the central micrograph in the bottom panel show cross sections of the thick sections of the fiber. The cavity is visible. The cavities may have an irregular perimeter towards the outer wall of the fiber. The outer wall contains pores. The left and right micrographs in the bottom panel show cross-sections of the thin sections of the fiber. Compared to the cavities in the thick sections, the thin sections have a dense or condensed structure. As can be seen, the thin sections have pores. Figure 5F shows an electron micrograph of a cross-section of the outer wall of a cavity of a fiber according to an embodiment of the invention. Again, it can be seen that the outer wall has a porous structure.

[0116] 8 shows a schematic diagram of a hollow fiber 21 according to an embodiment of the present invention. The hollow fiber 21 has a continuous cavity 23. Such hollow fibers can be prepared using a conventional melt spinning process without the application of a temperature gradient.

[0117] Example 2: Antimony content test For example, the antimony content of the fibers obtained using cooling under a temperature gradient as in Example 1 was tested by Laboratory Dr. Matt, Schaan, Liechtenstein. In principle, the toxic element antimony can be present as a residue from the catalysts used during the production process of the polymer. Antimony content was tested as follows: The fibers of Example 1 are placed in water and (a) heated to the boiling point of water; (b) stored in water for 8 weeks; (c) further stored in a glass filled with water and air (sealed, 1 / 3 air, 2 / 3 water) for 4 weeks. No antimony was detected in the fiber or water (antimony S6 < 0.1mg / kg ICP-MS), thus demonstrating that fiber can be produced without the use of toxic antimony.

[0118] Example 3: Moisture absorption test In this example, the moisture absorption of fibers according to embodiments of the present invention, obtained, for example, using cooling under a temperature gradient as in Example 1, was tested in comparison with a commercially available cotton fiber and two additional commercially available synthetic fibers, namely, polyester (PES) fiber and polybutylene succinate (PBS) fiber. In addition, the drying properties of the fibers were also tested. The fibers and sources are listed in Table 2 below.

[0119] [Table 2]

[0120] The moisture absorption test setup is shown in Figure 6A. Four fiber spheres, each about 4 cm long (from left to right: cotton, fiber according to an embodiment of the invention (obtained using cooling under a temperature gradient), polyester (PES), polybutylene succinate (PBS), are attached to a rod with a clamp. The fiber spheres are prepared to have approximately the same length and volume by visual inspection.

[0121] FIG. 6B shows the test setup just before testing. Four Petri dishes are filled with water and about 3% by volume of blue ink to provide blue water, also referred to herein as "colored water," "liquid," or "colored liquid." The test is performed as follows: before starting the test, the four fiber balls are slightly moistened with a water sprayer to provide uniform moisture content. The weight of the fiber balls is measured before immersion in the colored liquid. The weight of the fiber balls is listed in Table 3 below. Then, a rod with four fiber balls (from left to right: cotton, fiber according to an embodiment of the invention (obtained using cooling under a temperature gradient), polyester (PES), polybutylene succinate (PBS) is suspended and the four fiber balls are simultaneously immersed about 1 cm into the colored liquid. The timing begins when the fiber balls are immersed in the liquid.

[0122] The staining over time is recorded by a camera. Figure 6C shows the test about 13 seconds after the fiber ball is immersed in the liquid. Figure 6D shows that the cotton fiber (first from the left) and the fiber according to the embodiment of the invention (obtained with cooling under a temperature gradient, second from the left) are stained approximately 3.5 minutes after the fiber ball is immersed in the liquid. In general, the staining of the cotton fiber and the fiber according to the embodiment of the invention can be observed from 2 minutes after the fiber ball is immersed in the coloring liquid. Figure 6E shows that the cotton fiber and the fiber according to the embodiment of the invention (obtained with cooling under a temperature gradient) are significantly swollen in the part directly in contact with the liquid 6 minutes after the fiber ball is immersed in the liquid. The PBS fiber ball (fourth from the left) also shows very slight staining in the center, which, however, disappears when the test is repeated. Figure 6F shows the test just before the fiber ball is immersed in the liquid for 15 minutes and then stopped. After 15 minutes in the blue liquid, the fiber balls are simultaneously lifted out of the liquid. The fiber balls are hung above a Petri dish for 1 minute to drain. The fiber balls are compared by visual inspection and weighed (in this regard, the weight of the fiber balls was measured before immersion in the colored water and compared after removing the fibers and after draining). The fiber balls are then dried at 40° C. for 10 minutes and weighed again. Figure 7 shows the drying of the fiber balls in a Petri dish at 40° C. for 10 minutes. The results are shown in Table 3.

[0123] [Table 3] * For example, fibers obtained using cooling under a temperature gradient, as described in Example 1. ** in one test run, up to 8 mm in parts, but this could not be reproduced (the results were likely obtained with fabrics contaminated with disinfectant).

[0124] As can be seen in Figure 6F, after 15 minutes of immersion in the blue liquid, the fiber sphere according to the embodiment of the invention (second from the left, obtained using cooling under a temperature gradient) has substantially maintained its shape. The liquid has migrated higher in the fiber sphere according to the embodiment of the invention (second from the left) than in the cotton fiber sphere (first on the left). At the bottom of the cotton fiber sphere, aggregation due to swelling can be observed.

[0125] The fibers according to the embodiments of the invention (obtained using cooling under a temperature gradient) and cotton absorb most of the liquid, see Table 3 "Weight difference with respect to a dry fiber ball after 15 minutes in liquid". After the draining stage, the fibers according to the embodiments of the invention retain more liquid than cotton, both in absolute and percentage values, see Table 3 "Weight difference with respect to a dry fiber ball after 15 minutes in liquid and about 1 minute draining". The time required for drying of the fibers according to the embodiments of the invention is significantly shorter than that of cotton, which is consistent with Table 3, see "Weight difference after drying for 10 minutes at 40°C". In contrast to the other two synthetic fibers (PES and PBS), the fibers according to the embodiments of the invention are able to absorb liquid.

[0126] In conclusion, the fibers according to the embodiments of the invention (obtained using cooling under a temperature gradient) have slightly better moisture absorption than cotton. Furthermore, the fibers according to the embodiments of the invention have significantly better properties when dry. Therefore, the fibers according to the embodiments of the invention can be used to generate surfaces that can absorb moisture and be dried again with less energy than cotton requires.

[0127] Example 4: Further characteristics of fibers according to embodiments of the invention Further properties of fibers according to embodiments of the present invention (e.g., obtained using cooling under a temperature gradient as in Example 1) compared to known commercially available fibers used in the manufacture of textiles are listed in Table 4 below.

[0128] [Table 4] * For example, fibers obtained using cooling under a temperature gradient, as described in Example 1. An "X" indicates that the respective characteristic has been achieved.

[0129] As can be seen from Table 4, the fibers according to the embodiments of the invention (obtained using cooling under a temperature gradient) can be prepared with flame retardants, are hydrophilic, can be prepared without antimony, are biodegradable according to EN 13432, are stain resistant, wrinkle resistant and can be prepared with a certain percentage of renewable raw materials. The water consumption required for the preparation of the fibers according to the embodiments of the invention is much lower than that of cotton. Furthermore, the area required for the preparation of 1 ton (1000 kg) of the fibers according to the embodiments of the invention is also much smaller than that of cotton. Thus, the fibers according to the embodiments of the invention are beneficial from an ecological point of view compared to cotton.

[0130] Example 5: Garments containing fibers according to embodiments of the present invention Fibers according to embodiments of the invention (obtained, for example, using cooling under a temperature gradient, as in Example 1), and in particular yarns made from said fibers, were used to manufacture a shirt. Various views of the shirt are shown in Figures 9A, 9B, and 9C. The shirt comprises about 40% fibers according to embodiments of the invention and about 60% cotton.

[0131] The present invention is further characterized by the following: 1.- Spinning a melt containing an aliphatic polyester, an aliphatic-aromatic polyester, and a polyhydroxyalkanoate through a hollow fiber spinning nozzle to obtain a precursor fiber; and - cooling the precursor fiber under a temperature gradient, thereby obtaining a fiber. 4. A fiber obtainable or obtained by a process comprising: 2. The fiber of claim 1, wherein the temperature gradient is generated by one or more temperature control elements. 3. The fiber of paragraph 2, wherein the one or more temperature control elements are arranged to generate a temperature gradient in a direction substantially perpendicular to the longitudinal direction of the precursor fiber. 4. The fiber of paragraph 2 or 3, wherein the one or more temperature control elements are arranged to generate a temperature gradient in a direction substantially parallel to the cross-section of the precursor fiber. 5. The fiber of any one of paragraphs 2 to 4, wherein the one or more temperature control elements are arranged such that the temperature of one outer surface of the precursor fiber is lower than the temperature of the opposite outer surface. 6. The fiber of any one of paragraphs 2 to 5, wherein one or more temperature control elements are positioned such that the precursor fiber is cooled from one side. 7. The fiber according to item 6, wherein the cooling is performed by air cooling. 8. The fiber according to item 6 or 7, wherein the air cooling is performed by using an air-cooling assembly arranged on one side of the precursor fiber to supply an air flow from the one side to the precursor fiber in a direction substantially perpendicular to the longitudinal direction of the precursor fiber. 9. The fiber of claim 8, wherein air flow from the side opposite the one side is prevented by turning off an air-cooling assembly located on the opposite side of the precursor fiber. 10. The fiber according to item 8, wherein air flow from the opposite side of the precursor fiber is prevented by disposing one or more baffles between air-cooled assemblies disposed on opposite sides of the precursor fiber, thereby preventing air flow from the opposite side to the precursor fiber over at least a portion along the length of the precursor fiber. 11. Aliphatic polyester is aliphatic C2-C 20Dicarboxylic acids and aliphatic C2-C 12 The fiber of any one of the preceding claims, comprising a diol. 12. The fiber of any one of the preceding paragraphs, wherein the aliphatic polyester is selected from the group consisting of polybutylene succinate (PBS), polyethylene oxalate, polyethylene malonate, polyethylene succinate, polypropylene oxalate, polypropylene malonate, polypropylene succinate, polybutylene oxalate, polybutylene malonate, polybutylene succinate-co-adipate (PBSA), polybutylene succinate-co-azelate (PBSAz), polybutylene succinate-co-brasslate (PBSBr), and any combination thereof. 13. The fiber of any one of the preceding paragraphs, wherein the aliphatic polyester is selected from the group consisting of polybutylene succinate (PBS), polybutylene succinate-co-adipate (PBSA), polybutylene succinate-co-azelate (PBSAz), polybutylene succinate-co-brasslate (PBSBr), and any combination thereof. 14. The fiber according to any one of the preceding paragraphs, wherein the aliphatic polyester is polybutylene succinate (PBS). 15. The fiber according to any one of the preceding paragraphs, wherein the fiber contains an aliphatic polyester in an amount of 30 to 70% by weight, based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate. 16. Aliphatic-aromatic polyesters are C2-C 12 Aliphatic dicarboxylic acids, aromatic dicarboxylic acids, and aliphatic C2-C 12 The fiber of any one of the preceding claims, comprising a diol. 17. The fiber of any one of the preceding paragraphs, wherein the aliphatic-aromatic polyester is selected from the group consisting of polybutylene adipate terephthalate (PBAT), polybutylene succinate terephthalate (PBST), polybutylene sebacate terephthalate (PBSeT), and any combination thereof. 18. The fiber of any one of the preceding paragraphs, wherein the aliphatic-aromatic polyester is polybutylene adipate terephthalate (PBAT). 19. The fiber according to any one of the preceding paragraphs, wherein the fiber contains aliphatic-aromatic in an amount of 10 to 60% by weight, based on 100% by weight of the total amount of aliphatic polyester, aliphatic-aromatic polyester, and polyhydroxyalkanoate. 20. Polyhydroxyalkanoates are C3-C 18 2. The fiber of any one of the preceding claims, comprising a hydroxyalkyl carboxylic acid. 21. The fiber of any one of the preceding paragraphs, wherein the polyhydroxyalkanoate is selected from the group consisting of polyhydroxybutyrate, polyhydroxyvalerate, polyhydroxybutyrate-co-hydroxyvalerate, polyhydroxybutyrate-co-hydroxyhexanoate, and any combination thereof. 22. The fiber of any one of the preceding paragraphs, wherein the polyhydroxyalkanoate is selected from the group consisting of poly-3-hydroxybutyrate (P3HB), poly-4-hydroxybutyrate (P4HB), poly-3-hydroxyvalerate (PHV), poly(3-hydroxybutyrate-co-4-hydroxybutyrate), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), and any combination thereof. 23. The fiber of any one of the preceding paragraphs, wherein the polyhydroxyalkanoate is polyhydroxybutyrate-co-hydroxyhexanoate, preferably poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH). 24. The fiber according to any one of the preceding paragraphs, wherein the fiber contains polyhydroxyalkanoate in an amount of 1 to 25% by weight, based on 100% by weight of the total amount of aliphatic polyester, aliphatic-aromatic polyester, and polyhydroxyalkanoate. 25. The fiber according to any one of the preceding paragraphs, wherein the fiber comprises 42 to 62% by weight of the aliphatic polyester, 26 to 46% by weight of the aromatic-aliphatic polyester, and 2 to 22% by weight of the polyhydroxyalkanoate, based on 100% by weight of the total amount of the aliphatic polyester, the aromatic-aliphatic polyester, and the polyhydroxyalkanoate. 25a. The fiber of any one of the preceding paragraphs, wherein the aliphatic polyester is polybutylene succinate (PBS), the aliphatic-aromatic polyester is polybutylene adipate terephthalate (PBAT), and the polyhydroxyalkanoate is poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH). 26. The fiber of any one of the preceding claims, which is a woven fiber. 27. The fiber of any one of the preceding claims, further comprising at least one additive. 28. The fiber according to paragraph 27, wherein the at least one additive is selected from the group consisting of flame retardants, matting agents, fluorescent markers, antimicrobial agents, fillers, and any combination thereof. 29. The fiber according to item 28, wherein the additive is a flame retardant. 30. The fiber according to paragraph 29, wherein the flame retardant is a phosphate selected from the group consisting of ammonium dihydrogen phosphate ([NH4][H2PO4]), diammonium hydrogen phosphate ([NH4]2[HPO4]), triammonium phosphate ([NH4]3[PO4]), ammonium polyphosphate, and any combination thereof. 31. The fiber according to item 30, wherein the phosphate is diammonium hydrogen phosphate ([NH4]2[HPO4]). 32. The fiber according to any one of items 27 to 31, comprising a flame retardant in an amount of 0.01 to 5% by weight, preferably 0.1 to 4% by weight, more preferably 0.2 to 3% by weight, and even more preferably 0.3 to 2% by weight, relative to 100% by weight of the total weight of the fiber. 33. The fiber according to any one of items 27 to 32, wherein the additive is a matting agent. 34. The fiber according to item 33, wherein the matting agent is zinc sulfide. 35. The fiber according to any one of claims 27 to 34, wherein the additive is a fluorescent marker. 36. The fiber according to any one of items 27 to 35, wherein the additive is an antibacterial agent. 37. The fiber according to paragraph 36, wherein the antibacterial agent is zinc encapsulated with polyethylene terephthalate. 38. The fiber according to any one of items 27 to 37, wherein the additive is a filler. 39. The fiber according to paragraph 38, wherein the filler is or comprises lignin. 40. The fiber according to any one of items 27 to 39, comprising a total amount of additives of 15% by weight or less, preferably 10% by weight or less, more preferably 7% by weight or less, even more preferably 5% by weight or less, still more preferably 4% by weight or less, and even more preferably 3 to 4% by weight, based on 100% by weight of the total weight of the fiber. 41. The fiber according to any one of the preceding items, having a fineness of 0.5 to 8 den, preferably 0.8 to 6 den, more preferably 0.9 to 3 den, even more preferably 1.0 to 2 den, still more preferably 1.0 to 1.5 den, and even more preferably 1.1 to 1.2 den. 42. The fiber of any one of the preceding claims, which is a staple fiber. Item 43. The fiber according to item 42, having a staple length of 2 to 80 mm, preferably 5 to 70 mm, more preferably 10 to 60 mm, even more preferably 15 to 50 mm, still more preferably 20 to 40 mm, still more preferably 22 to 35 mm, and still more preferably 25 to 32 mm. 44. The fiber according to any one of items 1 to 43, which is a filament. 45. A fiber according to any one of the preceding paragraphs, having biodegradability according to EN 13432. 46. ​​A fiber made from a blend containing an aliphatic polyester, an aliphatic-aromatic polyester, and a polyhydroxyalkanoate, the fiber includes two types of sections in a longitudinal direction, one type of section being a thick section and the other type of section being a thin section, the thick section and the thin section extending in a direction perpendicular to the longitudinal direction of the fiber, the extent of the perpendicular extension of the thick section being greater than the extent of the perpendicular extension of the thin section; A fiber, at least a portion of the thicker portion having a cavity and at least a portion of the thinner portion having a dense structure. 47. The fiber of paragraph 46, wherein the thickened and thinned sections are arranged in an alternating pattern along the length of the fiber. 48. The fiber according to paragraph 46 or 47, wherein the lengths of the thick and thin portions along the longitudinal direction of the fiber are irregular. 49. The fiber according to any one of items 46 to 48, wherein the extension range of the cavities in the longitudinal direction of the fiber is greater than the extension range in a direction perpendicular to the longitudinal direction of the fiber. 50. The fiber according to any one of paragraphs 46 to 49, wherein the cavity has an irregular circumference. 51. The fiber according to item 50, wherein the circumference is irregular in a plane considered as perpendicular to the longitudinal direction of the fiber. 52. The fiber according to any one of items 46 to 51, which is a crimped fiber. 53. The fiber according to any one of items 46 to 52, which is the fiber according to any one of items 1 to 45. 54. A hollow fiber made from a blend containing an aliphatic polyester, an aliphatic-aromatic polyester, and a polyhydroxyalkanoate. 55. The hollow fiber of paragraph 55, further defined as in any one of paragraphs 4 to 39. 56. A yarn comprising the fiber according to any one of items 1 to 55. 57. A woven fabric comprising the fiber according to any one of items 1 to 55 or the yarn according to item 56. 58. The fabric according to paragraph 57, which is a clothing or household fabric. 59. The textile fabric according to paragraph 58, wherein the garment is selected from the group consisting of shirts, polo shirts, trousers, jackets, underwear, socks, coats, shoes, and shoelaces. 60. The textile according to paragraph 58, wherein the household textile is selected from the group consisting of curtains, rugs, blankets, bed sheets, comforters, comforter covers, cushion covers, and towels. 61. - spinning a melt comprising an aliphatic polyester, an aliphatic-aromatic polyester, and a polyhydroxyalkanoate through a hollow fiber spinning nozzle to obtain a precursor fiber; and - cooling the precursor fiber under a temperature gradient, thereby obtaining a fiber. Item 55. A method for preparing the fiber according to any one of items 1 to 54, comprising: 62. The method of paragraph 61, wherein the temperature gradient is generated by cooling the precursor fiber from one side. 63. The method according to item 61 or 62, wherein the cooling is carried out by air cooling. 64. The method according to any one of paragraphs 61 to 64, wherein the melt contains an aliphatic polyester in an amount of 30 to 70% by weight, based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate. 65. The method of any one of paragraphs 61 to 64, wherein the melt contains aliphatic-aromatic in an amount of 10 to 60% by weight, based on 100% by weight of the total amount of aliphatic polyester, aliphatic-aromatic polyester, and polyhydroxyalkanoate. 66. The method of any one of paragraphs 61 to 65, wherein the melt contains polyhydroxyalkanoate in an amount of 1 to 25% by weight, based on 100% by weight of the total amount of aliphatic polyester, aliphatic-aromatic polyester, and polyhydroxyalkanoate. 67. The method according to any one of paragraphs 61 to 66, wherein the melt contains the aliphatic polyester in an amount of 42 to 62% by weight, the aromatic-aliphatic polyester in an amount of 26 to 46% by weight, and the polyhydroxyalkanoate in an amount of 2 to 22% by weight, based on 100% by weight of the total amount of the aliphatic polyester, the aromatic-aliphatic polyester, and the polyhydroxyalkanoate. 68. The method of any one of paragraphs 61 to 67, wherein the melt further comprises at least one additive. 69. The method of claim 68, wherein the at least one additive is selected from the group consisting of flame retardants, matting agents, fluorescent markers, antimicrobial agents, fillers, and any combination thereof. 70. The method of claim 69, wherein the additive is a flame retardant. 71. The method according to item 70, wherein the melt contains a flame retardant in an amount of 0.01 to 5% by weight, preferably 0.1 to 4% by weight, more preferably 0.2 to 3% by weight, and even more preferably 0.3 to 2% by weight, based on 100% by weight of the total weight of the melt. 72. The method according to any one of items 68 to 71, wherein the total weight of the additives is 15% by weight or less, preferably 10% by weight or less, more preferably 7% by weight or less, even more preferably 5% by weight or less, still more preferably 4% by weight or less, and even more preferably 3 to 4% by weight, based on 100% by weight of the total weight of the melt. 73. The method of any one of paragraphs 61 to 72, wherein the fibers are prepared as staple fibers. 74. The method of any one of paragraphs 61 to 72, wherein the fibers are prepared as filaments. 75. Use of a melt comprising an aliphatic polyester, an aliphatic-aromatic polyester, and a polyhydroxyalkanoate for the preparation of a fiber as defined in any one of paragraphs 1 to 53. 76. Use of melts containing aliphatic polyesters, aliphatic-aromatic polyesters, and polyhydroxyalkanoates for the preparation of hollow fibers. 77. Mixtures including aliphatic polyesters, and aliphatic-aromatic polyesters, and polyhydroxyalkanoates. 78. The mixture according to paragraph 77, wherein the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate are further defined as in any one of paragraphs 11 to 25. 79. The mixture according to item 77 or 78, wherein the aliphatic polyester is polybutylene succinate (PBS), the aliphatic-aromatic polyester is polybutylene adipate terephthalate (PBAT), and the polyhydroxyalkanoate is poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH). 80. The mixture according to any one of paragraphs 77 to 79, wherein the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate are present in the form of particles. 81. The mixture according to paragraph 80, wherein the particles are selected from the group consisting of granules, pellets, extrudates, beads, prills, and any combination thereof. 82. The mixture according to paragraph 80 or 81, wherein the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate are in the form of granules. 83. The mixture according to any one of claims 77 to 82, comprising an aliphatic polyester in an amount of 30 to 70% by weight, based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate. 84. The mixture according to claims 77 to 83, comprising an aliphatic-aromatic polyester in an amount of 10 to 60% by weight, based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate. 85. The mixture according to any one of claims 77 to 84, comprising polyhydroxyalkanoate in an amount of 1 to 25% by weight, based on 100% by weight of the total amount of aliphatic polyester, aliphatic-aromatic polyester, and polyhydroxyalkanoate. 86. The mixture according to any one of paragraphs 77 to 85, comprising 42 to 62% by weight of the aliphatic polyester, 26 to 46% by weight of the aromatic-aliphatic polyester, and 2 to 22% by weight of the polyhydroxyalkanoate, based on 100% by weight of the total amount of the aliphatic polyester, the aromatic-aliphatic polyester, and the polyhydroxyalkanoate. 87. The mixture according to any one of paragraphs 77 to 86, further comprising at least one additive. 88. The mixture according to paragraph 87, wherein at least the additive is selected from the group consisting of flame retardants, matting agents, fluorescent markers, antimicrobial agents, fillers, and any combination thereof. 89. The mixture according to paragraph 88, wherein the additive is a flame retardant. 90. The mixture according to item 89, comprising a flame retardant in an amount of 0.01 to 5% by weight, preferably 0.1 to 4% by weight, more preferably 0.2 to 3% by weight, and even more preferably 0.3 to 2% by weight, based on 100% by weight of the total weight of the mixture. 91. The mixture according to any one of items 87 to 90, wherein the total amount of additives is 15% by weight or less, preferably 10% by weight or less, more preferably 7% by weight or less, even more preferably 5% by weight or less, still more preferably 4% by weight or less, and even more preferably 3 to 4% by weight, based on 100% by weight of the total weight of the mixture. 92. Use of a mixture comprising an aliphatic polyester, an aliphatic-aromatic polyester, and a polyhydroxyalkanoate for the preparation of a fiber as defined in any one of paragraphs 1 to 76. 93. Use of a mixture comprising an aliphatic polyester, an aliphatic-aromatic polyester, and a polyhydroxyalkanoate for the preparation of hollow fibers.

Claims

1. 1. A method for preparing a fiber, comprising: - spinning a melt comprising the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate through a hollow fiber spinning nozzle to obtain a precursor fiber; and - cooling the precursor fiber under a temperature gradient, thereby obtaining the fiber. Including, Optionally, the temperature gradient is generated by one or more temperature control elements, preferably arranged to generate the temperature gradient in a direction substantially perpendicular to a longitudinal direction of the precursor fiber; Optionally, the one or more temperature control elements are positioned to allow the precursor fiber to be cooled from one side, preferably by air cooling. method.

2. The aliphatic polyester is 2 ~C 20 Dicarboxylic acids and aliphatic C 2 ~C 12 10. The method of claim 1, comprising a diol, Optionally, the aliphatic polyester is selected from the group consisting of polybutylene succinate (PBS), polyethylene oxalate, polyethylene malonate, polyethylene succinate, polypropylene oxalate, polypropylene malonate, polypropylene succinate, polybutylene oxalate, polybutylene malonate, polybutylene succinate-co-adipate (PBSA), polybutylene succinate-co-azelate (PBSAz), polybutylene succinate-co-brasslate (PB SBr), and any combination thereof, preferably the aliphatic polyester is selected from the group consisting of polybutylene succinate (PBS), polybutylene succinate-co-adipate (PBSA), polybutylene succinate-co-azelate (PBSAz), polybutylene succinate-co-brasslate (PBSBr), and any combination thereof, preferably the aliphatic polyester is polybutylene succinate (PBS); Optionally, the fiber comprises the aliphatic polyester in an amount of 30 to 70% by weight, based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate.

10. The method of claim 1.

3. The aliphatic-aromatic polyester is 2 ~C 12 Aliphatic dicarboxylic acids, aromatic dicarboxylic acids, and aliphatic C 2 ~C 12 10. The method of claim 1, comprising a diol, Optionally, the aliphatic-aromatic polyester is selected from the group consisting of polybutylene adipate terephthalate (PBAT), polybutylene succinate terephthalate (PBST), polybutylene sebacate terephthalate (PBSeT), and any combination thereof, preferably, the aliphatic-aromatic polyester is polybutylene adipate terephthalate (PBAT); Optionally, the fiber comprises the aliphatic-aromatic polyester in an amount of 10 to 60% by weight, based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate.

10. The method of claim 1.

4. The polyhydroxyalkanoate is C 3 ~C 18 10. The method of claim 1, comprising a hydroxyalkyl carboxylic acid, Optionally, the polyhydroxyalkanoate is selected from the group consisting of polyhydroxybutyrate-co-hydroxyhexanoate, polyhydroxybutyrate, polyhydroxyvalerate, polyhydroxybutyrate-co-hydroxyvalerate, and any combination thereof; Optionally, the polyhydroxyalkanoate is selected from the group consisting of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), poly-3-hydroxybutyrate (P3HB), poly-4-hydroxybutyrate (P4HB), poly-3-hydroxyvalerate (PHV), poly(3-hydroxybutyrate-co-4-hydroxybutyrate), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), and any combination thereof; preferably, the polyhydroxyalkanoate is polyhydroxybutyrate-co-hydroxyhexanoate; more preferably, the polyhydroxyalkanoate is poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH); Optionally, the fiber comprises the polyhydroxyalkanoate in an amount of 1 to 25% by weight, based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate.

10. The method of claim 1.

5. the fibers comprise 42 to 62% by weight of the aliphatic polyester, 26 to 46% by weight of the aliphatic-aromatic polyester, and 2 to 22% by weight of the polyhydroxyalkanoate, relative to 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate; and / or The aliphatic polyester is polybutylene succinate (PBS), the aliphatic-aromatic polyester is polybutylene adipate terephthalate (PBAT), and the polyhydroxyalkanoate is poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH); 10. The method of claim 1.

6. 10. The method of claim 1, wherein the fiber further comprises at least one additive, Optionally, the at least one additive is selected from the group consisting of a flame retardant, a matting agent, a fluorescent marker, an antimicrobial agent, a filler, and any combination thereof; Optionally, the flame retardant is ammonium dihydrogen phosphate ([NH 4 ][H 2 PO 4 ]), diammonium hydrogen phosphate ([NH 4 ] 2 [HPO 4 ]), triammonium phosphate ([NH 4 ] 3 [PO 4 ]), ammonium polyphosphate, and any combination thereof; 10. The method of claim 1.

7. A fiber made from a blend comprising an aliphatic polyester, an aliphatic-aromatic polyester, and a polyhydroxyalkanoate, the fiber includes two types of portions in the longitudinal direction, one type of portion being a thick portion and the other type of portion being a thin portion, the thick portion and the thin portion extending in a direction perpendicular to the longitudinal direction of the fiber, the extent of extension of the thick portion in the perpendicular direction being greater than the extent of extension of the thin portion in the perpendicular direction; At least a portion of the thick-walled portion has a cavity, and at least a portion of the thin-walled portion has a dense structure; Optionally, the thickened and thinned portions are arranged in an alternating pattern along the length of the fiber; Optionally biodegradable, preferably in accordance with EN 13432, fiber.

8. The aliphatic polyester is 2 ~C 20 Dicarboxylic acids and aliphatic C 2 ~C 12 8. The fiber of claim 7, comprising a diol, Optionally, the aliphatic polyester is selected from the group consisting of polybutylene succinate (PBS), polyethylene oxalate, polyethylene malonate, polyethylene succinate, polypropylene oxalate, polypropylene malonate, polypropylene succinate, polybutylene oxalate, polybutylene malonate, polybutylene succinate-co-adipate (PBSA), polybutylene succinate-co-azelate (PBSAz), polybutylene succinate-co-brasslate (PBS Br), and any combination thereof, preferably, the aliphatic polyester is selected from the group consisting of polybutylene succinate (PBS), polybutylene succinate-co-adipate (PBSA), polybutylene succinate-co-azelate (PBSAz), polybutylene succinate-co-brasslate (PBSBr), and any combination thereof, more preferably, the aliphatic polyester is polybutylene succinate (PBS); Optionally, the aliphatic polyester is contained in an amount of 30 to 70% by weight, based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate. The fiber of claim 7.

9. The aliphatic-aromatic polyester is 2 ~C 12 Aliphatic dicarboxylic acids, aromatic dicarboxylic acids, and aliphatic C 2 ~C 12 8. The fiber of claim 7, comprising a diol, Optionally, the aliphatic-aromatic polyester is selected from the group consisting of polybutylene adipate terephthalate (PBAT), polybutylene succinate terephthalate (PBST), polybutylene sebacate terephthalate (PBSeT), and any combination thereof, preferably, the aliphatic-aromatic polyester is polybutylene adipate terephthalate (PBAT); Optionally, the aliphatic-aromatic polyester is contained in an amount of 10 to 60% by weight, based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate. The fiber of claim 7.

10. The polyhydroxyalkanoate is C 3 ~C 18 8. The fiber of claim 7, comprising a hydroxyalkyl carboxylic acid, Optionally, the polyhydroxyalkanoate is selected from the group consisting of polyhydroxybutyrate-co-hydroxyhexanoate, polyhydroxybutyrate, polyhydroxyvalerate, polyhydroxybutyrate-co-hydroxyvalerate, and any combination thereof; Optionally, the polyhydroxyalkanoate is selected from the group consisting of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH), poly-3-hydroxybutyrate (P3HB), poly-4-hydroxybutyrate (P4HB), poly-3-hydroxyvalerate (PHV), poly(3-hydroxybutyrate-co-4-hydroxybutyrate), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), and any combination thereof; preferably, the polyhydroxyalkanoate is polyhydroxybutyrate-co-hydroxyhexanoate; more preferably, the polyhydroxyalkanoate is poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH); Optionally, the polyhydroxyalkanoate is contained in an amount of 1 to 25% by weight, based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate. The fiber of claim 7.

11. and / or comprising 42 to 62% by weight of the aliphatic polyester, 26 to 46% by weight of the aliphatic-aromatic polyester, and 2 to 22% by weight of the polyhydroxyalkanoate, based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate; The aliphatic polyester is polybutylene succinate (PBS), the aliphatic-aromatic polyester is polybutylene adipate terephthalate (PBAT), and the polyhydroxyalkanoate is poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH); The fiber of claim 7.

12. 8. The fiber of claim 7, further comprising at least one additive, Optionally, the at least one additive is selected from the group consisting of a flame retardant, a matting agent, a fluorescent marker, an antimicrobial agent, a filler, and any combination thereof; Optionally, the flame retardant is ammonium dihydrogen phosphate ([NH 4 ][H 2 PO 4 ]), diammonium hydrogen phosphate ([NH 4 ] 2 [HPO 4 ]), triammonium phosphate ([NH 4 ] 3 [PO 4 ]), ammonium polyphosphate, and any combination thereof; The fiber of claim 7.

13. A hollow fiber made from a blend comprising an aliphatic polyester, an aliphatic-aromatic polyester, and a polyhydroxyalkanoate, Optionally biodegradable, preferably in accordance with EN 13432, Hollow fiber.

14. A mixture comprising an aliphatic polyester, an aliphatic-aromatic polyester, and a polyhydroxyalkanoate, the mixture comprising 30 to 70% by weight of the aliphatic polyester, 10 to 60% by weight of the aliphatic-aromatic polyester, and 1 to 25% by weight of the polyhydroxyalkanoate, relative to 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate; optionally, the aliphatic polyester is present in an amount of 42 to 62% by weight, the aliphatic-aromatic polyester is present in an amount of 26 to 46% by weight, and the polyhydroxyalkanoate is present in an amount of 2 to 22% by weight, based on 100% by weight of the total amount of the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate; Further optionally, the aliphatic polyester is polybutylene succinate (PBS), the aliphatic-aromatic polyester is polybutylene adipate terephthalate (PBAT), and the polyhydroxyalkanoate is poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH); Optionally, the aliphatic polyester, the aliphatic-aromatic polyester, and the polyhydroxyalkanoate are in the form of granules. mixture.

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