Biodegradable polymer fibers made from renewable raw materials

Abstract

The present invention relates to biodegradable polymer fibers made from renewable raw materials and having good physical properties, to a method for their production and to their use.

Description

[Technical Field]

[0001] This invention relates to biodegradable polymer fibers made from renewable raw materials having good physical properties, as well as methods for producing the same and uses thereof. [Background technology]

[0002] Polymer fibers, i.e., fibers based on synthetic polymers, are mass-produced industrially. For this purpose, the underlying synthetic polymer is processed in a melt-spinning process. In this process, the thermoplastic polymer material is melted and guided in liquid form to a spinning beam by an extruder. The molten material is then guided from this spinning beam to a so-called spinning nozzle. The spinning nozzle typically has multiple perforations, from which individual capillaries (filaments) of the fiber are drawn. In addition to the melt-spinning procedure, wet or solvent spinning methods are also used in the production of spun fibers. For these methods, instead of a molten material, a highly viscous solution of the synthetic polymer is drawn through a nozzle with fine perforations. Those skilled in the art refer to both methods as so-called multi-stage spinning procedures.

[0003] The polymer fibers produced in this manner are used in textiles and / or technical applications. Here, the good dispersion properties of the polymer fibers in aqueous systems are advantageous, for example, in the production of wet-laid fleece. Furthermore, in textile applications, the good mechanical stiffness of the polymer fibers is advantageous, as it allows them to function well, for example, for post-processing of the fibers, such as stretching on a conveyor line. For textile applications, the low degree of thermal shrinkage of polymer fibers, particularly in the form of fleece, is also advantageous.

[0004] For their respective end uses or required intermediate processing steps, such as stretching and / or crimping, polymer fibers are typically modified or prepared by applying an appropriate finish or layer to the surface of the polymer fibers to be finished or processed.

[0005] Another possibility is that chemical modifications can be carried out on the polymer base structure itself, for example, by incorporating a compound having flame-retardant properties into the main chain and / or side chains of the polymer.

[0006] In addition, additives such as antistatic agents or coloring pigments can be introduced into the molten thermoplastic polymer or polymer fiber during the multi-stage spinning process.

[0007] The dispersion behavior of polymer fibers is influenced, in particular, by the properties of the synthetic polymer. Therefore, especially for thermoplastic polymer fibers, the dispersion characteristics in aqueous systems are influenced by the finish or layer applied to the surface. [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] In recent years, there has been a growing demand for textiles that, in addition to being manufactured from renewable raw materials, not only meet the above requirements but also require little to no adjustments in subsequent applications, thereby allowing the continued use of existing processes and machinery.

[0009] Therefore, the challenge to be addressed is to provide polymer fibers made from renewable raw materials that possess good physical properties, thereby enabling good post-processing of the fibers, for example, during stretching on a conveyor line, and furthermore, that are biodegradable yet exhibit a small degree of thermal shrinkage. It would be even more advantageous if the polymer fibers made from renewable raw materials possessed good dispersion properties, particularly long-term dispersibility, and could be used even after longer-term storage. [Means for solving the problem]

[0010] The problems described herein are solved by a two-component polymer fiber according to the present invention, wherein the fiber comprises component A (core) and component B (shell), the melting point of the thermoplastic polymer in component A is at least 5°C higher than the melting point of the thermoplastic polymer in component B, the fiber material containing component A contains biopolymer A, and the fiber material containing component B contains biopolymer B.

[0011] Two-component polymer fibers are typically stored as tows after the spinning process, and then stretched on a conveyor line and further processed through specific steps. The tows can also be processed directly, and the feeding of the tows into so-called canisters can be partially or completely omitted.

[0012] By combining a specific biopolymer, namely a combination of component A (core) and component B (shell), with a specific stretching, a two-component polymer fiber according to the present invention is obtained, which also has lower thermal shrinkage. [Modes for carrying out the invention]

[0013] polymer The polymer used in this invention is a thermoplastic polycondensate based on so-called biopolymers.

[0014] The "thermoplastic polymer" according to the present invention refers to a plastic that can be molded (thermoplastically) within a specific temperature range, preferably in the range of 25°C to 350°C. This process is reversible; that is, it can be optionally repeated many times by cooling and reheating to a molten state, as long as so-called thermal decomposition of the material does not occur due to overheating. This is where thermoplastic polymers differ from thermosetting plastics and elastomers.

[0015] Among thermoplastic polycondensates based on so-called biopolymers, synthetic biopolymers, particularly those suitable for melt spinning, are preferred.

[0016] For the purposes of the present invention, the term "synthetic biopolymer" refers to materials that include bio-based raw materials (renewable raw materials). In this way, they are distinguished from conventional crude oil-based materials or plastics, such as polyethylene (PE), polypropylene (PP) and polyvinyl chloride (PVC).

[0017] The two-component fibers are made from a degradable synthetic biopolymer, where the term biodegradable is defined, for example, by ASTM D5338-15 (Standard Test Method for Determining Aerobic Biodegradation of Plastic Materials Under Controlled Composting Conditions, Incorporating Thermophilic Temperatures, ASTM International, West Conshohocken, PA, 2015, www.astm.org).

[0018] Bio-polymer A (core) Synthetic biopolymer A containing component A is a biopolymer that includes aliphatic polyesters, particularly, lactic acid, hydroxybutyric acid, and / or glycolic acid, preferably lactic acid and / or glycolic acid, particularly biopolymers containing repeating units of lactic acid. Polylactic acid is particularly preferred for this.

[0019] Aliphatic polyesters are understood to be polyesters that typically have at least about 50 mol%, in some preferred embodiments at least about 60 mol%, and in more preferred embodiments at least about 70 mol% of aliphatic monomers.

[0020] "Polylactic acid" is understood to mean a polymer containing lactic acid units. Such polylactic acid is usually produced by the condensation of lactic acid, but is also produced by the ring-opening polymerization of lactide under suitable conditions.

[0021] According to the present invention, particularly preferred polylactic acids include poly(glycolide-co-L-lactide), poly(L-lactide), poly(L-lactide-co-ε-caprolactone), poly(L-lactide-co-glycolide), poly(L-lactide-co-D,L-lactide), poly(D,L-lactide-co-glycolide), and poly(dioxanone). Such polymers are retailed, for example, by Boehringer Ingelheim Pharma KG (Germany) under the trade names Resomer(trademark) GL903, Resomer(trademark) L206S, Resomer(trademark) L207S, Resomer(trademark) L209S, Resomer(trademark) L210, Resomer(trademark) L210S, Resomer(trademark) LC703S, Resomer(trademark) LG824S, Resomer(trademark) LG855S, Resomer(trademark) LG857S, Resomer(trademark) LR704S, Resomer(trademark) LR706S, Resomer(trademark) LR708, Resomer(trademark) LR927S, Resomer(trademark) RG509S, and Resomer(trademark) X206S.

[0022] For the purposes of the present invention, particularly advantageous polylactic acid, especially poly-D, poly-L, or poly-D,L-lactic acid.

[0023] The term "polylactic acid" generally refers to homopolymers of lactic acid, such as y(L-lactic acid), poly(D-lactic acid), poly(DL-lactic acid), mixtures thereof, and copolymers comprising lactic acid as the main component and a low proportion, preferably less than 10 mol%, of copolymerizable comonomers.

[0024] Other materials suitable for biopolymer A include polylactic acid, polyglycolic acid, polyalkylene carbonates (such as polyethylene carbonate), polyhydroxyalkanoates (PHA), polyhydroxybutyrate (PHB), polyhydroxyvalerate (PHV), and copolymers or terpolymers based on polyhydroxybutyrate-hydroxyvalerate copolymer (PHBV).

[0025] In the most preferred embodiment, biopolymer A is solely a thermoplastic polymer based on lactic acid.

[0026] The polylactic acid used in the present invention preferably has a number-average molecular weight (Mn), as measured by gel permeation chromatography or end-group titration against a narrow distribution of polystyrene standards, of at least 500 g / mol, preferably a minimum of 1000 g / mol, most preferably a minimum of 5000 g / mol, more preferably a minimum of 10000 g / mol, and particularly a minimum of 25000 g / mol. On the other hand, the number-average molecular weight is preferably up to 1000000 g / mol, more preferably up to 500000 g / mol, most preferably up to 100000 g / mol, and particularly up to 50000 g / mol. Number-average molecular weights in the range from a minimum of 10000 g / mol to 500000 g / mol have also proven to be extremely advantageous within the scope of the present invention.

[0027] The weight-average molecular weight (Mw) of preferred lactic acid polymers, particularly poly-D, poly-L, or poly-D,L-lactic acid, as measured by gel permeation chromatography or end-group titration against a preferably narrowly distributed polystyrene standard, is preferably in the range of 750 g / mol to 5,000,000 g / mol, more preferably 5,000 g / mol to 1,000,000 g / mol, most preferably 10,000 g / mol to 500,000 g / mol, and particularly in the range of 30,000 g / mol to 500,000 g / mol, and the polydispersity of these polymers is preferably in the range of 1.5 to 5.

[0028] The intrinsic viscosity of particularly suitable lactic acid polymers, especially poly-D, poly-L, or poly-D,L-lactic acid, as measured at 25°C in chloroform with a preferred polymer concentration of 0.1%, is in the range of 0.5 dl / g to 8.0 dl / g, preferably in the range of 0.8 dl / g to 7.0 dl / g, and particularly in the range of 1.5 dl / g to 3.2 dl / g.

[0029] Within the scope of the present invention, it is extremely advantageous for biopolymers, particularly thermoplastic synthetic biopolymers, to have a glass transition temperature higher than 20°C, preferably higher than 25°C, more preferably higher than 30°C, most preferably higher than 35°C, and particularly higher than 40°C. Within the scope of the most preferred embodiments of the present invention, the glass transition temperature of the polymer is in the range of 35°C to 55°C, particularly in the range of 40°C to 50°C.

[0030] Furthermore, polymers having a melting temperature higher than 120°C, advantageously at least 130°C, preferably higher than 150°C, and up to 250°C, more preferably up to 210°C, most preferably in the range of 120°C to 250°C, and particularly in the range of 150°C to 210°C are especially preferred.

[0031] For this purpose, the glass temperature and melting temperature of the polymer are preferably determined by dynamic scanning calorimetry (abbreviated as "DSC"). In particular, the following procedure has proven advantageous in this context.

[0032] Biopolymer B (shell) The synthetic biopolymer B containing component B is preferably a biopolymer having a melting point at least 5°C lower than the melting point of the synthetic biopolymer A containing component A. Preferably, the melting point of biopolymer A is at least 10°C, more preferably at least 20°C, most preferably at least 30°C, and particularly at least 40°C higher than the melting point of synthetic biopolymer B.

[0033] Biopolymer B is an aliphatic polyester, and more particularly, an aliphatic polyester having a different repeating unit in its chemical structure than that of biopolymer A.

[0034] Aliphatic polyesters are understood to be polyesters that typically contain at least about 50 mol%, at least about 60 mol%, and at least about 70 mol%, of aliphatic monomers in some preferred embodiments.

[0035] Biopolymer B generally has a number-average molecular weight (Mn) of at least 10,000 daltons, particularly at least 12,000 daltons, more preferably at least 12,500 daltons, and up to a maximum of 120,000 daltons, particularly up to 100,000 daltons, and most preferably up to 80,000 daltons.

[0036] The number-average molecular weight (Mn) is generally determined by gel permeation chromatography against a narrow distribution of polystyrene standards.

[0037] Biopolymer B generally has a weight-average molecular weight (Mw) of at least 50,000 daltons, up to a maximum of 240,000 daltons, particularly up to 190,000 daltons, and most preferably up to 100,000 daltons.

[0038] The number-average molecular weight (Mn) is generally determined by gel permeation chromatography against a narrow distribution of polystyrene standards.

[0039] Biopolymer B typically has a melt flow index measured according to ASTM test procedure D1238-13 (ASTM D1238-13, Standard Test Method for Melt Flow Rates of Thermoplastics by Extrusion Plastometer, ASTM International, West Conshohocken, PA, 2013, www.astm.org) of 5 to 200 grams per 10 minutes, particularly 15 to 160 grams per 10 minutes, and especially preferably 20 to 120 grams per 10 minutes. The melt flow index is the weight (in grams) of polymer that can be extruded through the opening (0.0825 inches in diameter) of an extrusion rheometer when subjected to a force of 2160 grams for 10 minutes at 190°C.

[0040] Biopolymer B is preferably heated at a temperature of 160°C and 1000s -1The apparent viscosity measured under shear (s = seconds) is 50 Pa·s (Pascal-seconds) to 215 Pa·s, more preferably 70 Pa·s to 200 Pa·s.

[0041] It is important to consider here that biopolymer B, which is based on aliphatic polyester, is generally difficult to process if it has a high apparent viscosity, and if it has a viscosity that appears too low, it generally results in non-stretchable fibers that lack tensile strength and sufficient bonding ability (thermal bonding).

[0042] Biopolymer B having a melting temperature higher than 50°C, advantageously at least 100°C, preferably higher than 120°C, and up to 180°C, more preferably up to 160°C, most preferably in the range of 50°C to 160°C, and particularly in the range of 120°C to 160°C is also particularly preferred.

[0043] The glass transition temperature of biopolymer B is preferably at least 5°C lower, more preferably at least 10°C lower, and most preferably at least 15°C lower than the glass transition temperature of biopolymer A. The glass transition temperature is measured by DSC.

[0044] Examples of biopolymers B that can have a low melting point and a low glass transition temperature include aliphatic polyesters having repeating units with at least 5 carbon atoms (e.g., polyhydroxyvalerate, polyhydroxybutyrate-hydroxyvalerate copolymer, and polycaprolactone) and succinic acid-based aliphatic polymers (e.g., polybutylene succinate, polybutylene succinate adipate, and polyethylene succinate). More specific examples may include polyethylene oxalate, polyethylene malonate, polyethylene succinate, polypropylene oxalate, polypropylene malonate, polypropylene succinate, polybutylene oxalate, polybutylene malonate, polybutylene succinate, and mixtures and copolymers of these compounds. Such aliphatic polyesters are known from the prior art (International Publication No. 2007 / 070064) and are typically synthesized by condensation polymerization of polyols with aliphatic dicarboxylic acids or anhydrides.

[0045] Polybutylene succinate and butylene succinate copolymer are particularly preferred in relation to the present invention.

[0046] Biopolymer B, in particular, is suitable for thermal bonding due to its high degree of fusion and crystallization enthalpy. Generally, biopolymer B is selected to have a degree of crystallinity or latent heat of fusion (ΔHf) greater than about 25 joules / gram ("J / g"), more preferably greater than 35 J / g, and most preferably greater than 50 J / g. The latent heat of fusion (ΔHf), latent heat of crystallization (ΔHC), and crystallization temperature are measured using differential scanning calorimetry ("DSC") according to ASTM D-3418 (ASTM D3418-15, Standard Test Method for Transition Temperatures and Enthalpies of Fusion and Crystallization of Polymers by Differential Scanning Calorimetry, ASTM International, West Conshohocken, PA, 2015, www.astm.org).

[0047] By performing specific stretching using the parameter set defined by the present invention, it becomes possible to use not only biopolymer B but also more affordable biopolymer B variants, where the resulting two-component polymer fibers have lower thermal shrinkage. Thus, these specific stretching parameters enable the use of widely available biopolymer B. The specific biopolymer B used in embodiments of the present invention has a number-average molecular weight (Mn) of at least 10,000 daltons, more preferably at least 12,000 daltons, most preferably at least 12,500 daltons, and up to a maximum of 30,000 daltons, preferably up to 28,000, and more preferably up to 25,000 daltons.

[0048] The number-average molecular weight (Mn) is generally determined by gel permeation chromatography against a narrow distribution of polystyrene standards.

[0049] Certain biopolymers B have a melting temperature that is higher than 50°C, advantageously at least 100°C, preferably higher than 120°C, and up to 180°C, more preferably up to 160°C, most preferably in the range of 50°C to 160°C, and particularly in the range of 120°C to 160°C.

[0050] The glass transition temperature of a particular biopolymer B is preferably at least 5°C, more preferably at least 10°C, and most preferably at least 15°C lower than the glass transition temperature of biopolymer A. The glass transition temperature is measured by DSC.

[0051] Examples of certain biopolymers B that may have a low melting point and a low glass transition temperature include aliphatic polyesters having repeating units with at least 5 carbon atoms (e.g., polyhydroxyvalerate, polyhydroxybutyrate-hydroxyvalerate copolymer, and polycaprolactone) and succinate-based aliphatic polymers (e.g., polybutylene succinate, polybutylene succinate adipate, and polyethylene succinate). More specific examples may include polyethylene oxalate, polyethylene malonate, polyethylene succinate, polypropylene oxalate, polypropylene malonate, polypropylene succinate, polybutylene oxalate, polybutylene malonate, polybutylene succinate, and mixtures and copolymers of these compounds.

[0052] In relation to the present invention, polybutylene succinate and butylene succinate copolymer are particularly preferred as the specific biopolymer B.

[0053] In particular, certain biopolymers B having high fusion and crystallization enthalpy are suitable for thermal bonding. Generally, biopolymer B is selected to have a crystallinity or latent heat of fusion (ΔHf) greater than about 25 joules / gram ("J / g"), more preferably greater than 35 J / g, and most preferably greater than 50 J / g. The latent heat of fusion (ΔHf), latent heat of crystallization (ΔHC), and crystallization temperature are measured using differential scanning calorimetry ("DSC") according to ASTM D-3418 (ASTM D3418-15, Standard Test Method for Transition Temperatures and Enthalpies of Fusion and Crystallization of Polymers by Differential Scanning Calorimetry, ASTM International, West Conshohocken, PA, 2015, www.astm.org).

[0054] The melt viscosity of a specific biopolymer B, determined at a temperature of 190°C (Goettfert's Rheo-Tester 1000), is 200°C. -1 (Shear) 250 Pa·s to 400 Pa·s and 1200 s -1 (Shear) in the range of 125 Pa·s to 190 Pa·s, preferably 200s -1 (Shear) 260 Pa·s to 380 Pa·s and 1200 s -1 (Shear) in the range of 130 Pa·s to 180 Pa·s, more preferably 200 Pa·s -1 (shear) 275 Pa·s to 375 Pa·s and 1200 s -1 The shear pressure ranges from 135 Pa·s to 175 Pa·s.

[0055] Additives in polymers A and B The biopolymers A and B described above contain common additives such as antioxidants. In this regard, it has been proven that because biopolymers A and B are susceptible to oxidative degradation, the addition of antioxidants is unavoidable in the manufacturing and post-processing of the fibers.

[0056] Other common additives include pigments, stabilizers, surfactants, waxes, flow promoters, solid solvents, plasticizers, and other materials, such as nucleating agents, which are added to improve the processability of thermoplastic compositions.

[0057] The biopolymer B described above, and in particular certain biopolymer B based on its described properties, already allows for a reduction in the amount of additives, especially nucleating agents. Such nucleating agents, which are typically added, facilitate crystallization during the cooling of the fibers, thereby facilitating their processing. One type of such nucleating agent is a plurality of carbonic acids, for example, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and mixtures thereof, as described in U.S. Patent No. 6,177,193. The nucleating agent is typically present in biopolymer B at a concentration of less than about 0.5% by weight, less than about 0.25% by weight in some embodiments, and less than about 0.1% by weight in some embodiments.

[0058] At least 90% by weight of the two-component fiber according to the present invention comprises the above-mentioned aliphatic polyester biopolymers A and B, and the biopolymer B forming the shell typically contains less than about 10% by weight, preferably less than about 8% by weight, and more preferably less than 5% by weight of additives.

[0059] As mentioned above, the biopolymers described above require the addition of antioxidants because biopolymer B (shell) is particularly susceptible to oxidative degradation.

[0060] Based on the selected raw material and post-processing combination, the amount of antioxidant can be significantly reduced, specifically, the concentration of antioxidant in biopolymer B (shell) is 0.025% to 0.2% by weight.

[0061] The two-component fibers according to the present invention are combined into a tow after spinning and post-processed on a conveyor line using methods known from the prior art, in particular being stretched and, if necessary, further crimped or texturized. By selecting specific conveyor line parameters in the stretching, the specific biopolymer B described above can be used in particular.

[0062] polymer fibers The two-component fiber according to the present invention can be provided as a finite fiber, for example, a so-called staple fiber, or an infinite fiber (filament).

[0063] For better dispersion, the fibers are preferably present as staple fibers. The length of the above staple fibers is not fundamentally limited, but is generally 2 mm to 200 mm, preferably 3 mm to 120 mm, and more preferably 4 mm to 60 mm.

[0064] The yarn count of the two-component fiber, preferably a staple fiber, according to the present invention is 0.5 dtex to 30 dtex, preferably 0.7 dtex to 13 dtex. For some applications, yarn counts of 0.5 dtex to 3 dtex and fiber lengths of less than 10 mm, preferably less than 8 mm, more preferably less than 6 mm, and most preferably less than 5 mm are particularly suitable.

[0065] The two-component fibers according to the present invention exhibit low hot air shrinkage in the range of 0% to 10%, preferably more than 0% to 8%, as measured at 110°C.

[0066] By combining a specific biopolymer, namely a combination of component A (core) and component B (shell), with a specific stretching process, it becomes possible to transfer the stretching force to the core material, thereby achieving stretch-induced crystallization. In the two-component polymer fiber according to the present invention, this results in the low thermal shrinkage described above.

[0067] The polymer fibers according to the present invention are generally manufactured by a general procedure. First, the polymer is dried as needed and fed into an extruder. Next, the molten material is spun by a general apparatus having a corresponding nozzle. The outlet speed at the nozzle outlet surface is adjusted to a spinning speed such that the fibers are made of the desired count. The spinning speed is understood to mean the speed at which stiff filaments are drawn out.

[0068] The resulting fibers may have a circular, elliptical, or further suitable cross-section and shape.

[0069] The fiber filaments produced in this way are incorporated into yarn, which is then incorporated into tows. The tows are initially placed in canisters for further processing. The tows, which are intermittently stored in the canisters, are picked up to create large spinning fiber tows.

[0070] Another object of the present invention is a post-processing of spun fiber tows produced by the disclosed method using a conventional conveyor line, generally having a density of 10 ktex to 600 ktex and involving specific stretching. The stretching or feeding rate of the spun fiber tow to the draw frame is preferably 10 m / min to 110 m / min (feed rate). At this point, preparations that promote stretching but do not adversely affect the following properties can still be applied.

[0071] Stretching can be performed as a single step or, optionally, as part of a two-step stretching process (see, for example, U.S. Patent No. 3,816,486). One or more finishes can be applied before and during stretching, as in conventional methods.

[0072] The stretching according to the present invention is carried out at a stretch ratio of 1.2 to 6.0, preferably 2.0 to 4.0, particularly when using a specific biopolymer B, where the temperature of the spinning tow during stretching is 30°C to 80°C. Therefore, the stretching is carried out within the glass transition temperature range of the spinning tow to be stretched. The stretching according to the present invention is carried out under steam, i.e., in a so-called steam chamber, so that the stretching point of the fibers is reached in the steam chamber. The steam chamber is usually operated at a pressure of 3 bar.

[0073] By stretching the fibers under steam within the above temperature range, thermal shrinkage can be systematically controlled, reduced, and adjusted.

[0074] The preferred conveyor line configuration is as follows: The stretching is performed in a single step within the steam chamber between the draw frame S2 and the draw frame S1, i.e., the point of fiber stretching is reached within the steam chamber. All godets (usually 7) of S1 have a temperature of 30°C to 80°C. The entire stretching is performed within the steam chamber. The steam chamber is preferably operated at a steam pressure of 3 bar.

[0075] All godets (usually 7) in the next draw frame S2 are low temperature, where low temperature means room temperature (approximately 20°C to 35°C).

[0076] This so-called "cold drawing" mode has the effect that the drawing is not fixed at a high temperature on S2 under tension. The low-temperature S2 has the advantage that individual fibers do not have the risk of sticking to the high-temperature godet of S2.

[0077] Despite the "cold drawing", the fibers are still strong at high temperatures with fixation without tension in the oven and can withstand temperatures up to 100 °C without sticking.

[0078] The above "cold drawing" is particularly suitable for polybutylene succinate (FZ71), and the melt viscosity determined at a temperature of 190 °C (Goettfert's Rheo-Tester 1000) is 250 Pa·s to 325 Pa·s at 200 s -1 (shear) and 125 Pa·s to 150 Pa·s at 1200 s -1 (shear), preferably 260 Pa·s to 300 Pa·s at 200 s -1 (shear) and 130 Pa·s to 150 Pa·s at 1200 s -1 (shear), more preferably 270 Pa·s to 290 Pa·s at 200 s -1 (shear) and 135 Pa·s to 145 Pa·s at 1200 s -1 (shear) is in the range of 135 Pa·s to 145 Pa·s.

[0079] For polybutylene succinate (FZ91), the melt viscosity measured at a temperature of 190 °C (Goettfert's Rheo-Tester 1000) is 340 Pa·s to 400 Pa·s at 200 s -1 (shear) and 150 Pa·s to 190 Pa·s at 1200 s -1 (shear), preferably 350 Pa·s to 390 Pa·s at 200 s -1 (shear) and 160 Pa·s to 185 Pa·s at 1200 s -1 (shear), more preferably 360 Pa·s to 385 Pa·s at 200 s -1 (shear) and 160 Pa·s to 185 Pa·s at 1200 s -1As long as the shear pressure is in the range of 165 Pa·s to 180 Pa·s, the draw frame S2 operates at temperatures in the range of 60°C to 100°C, meaning that all godets (usually 7) have the above temperatures.

[0080] The spinning tow preferably has a density of 240ktex to 360ktex before stretching.

[0081] Similarly, for crimping / texturing of stretched fibers, conventional mechanical crimping methods can be applied using commonly known crimping machines as needed. The mechanical apparatus for fiber crimping is preferably a steam-operated, for example, press chamber. However, fibers crimped by other methods, such as three-dimensionally crimped fibers, can also be used. To perform crimping, the tow is first heated to a temperature usually in the range of 50°C to 100°C, preferably 70°C to 85°C, more preferably about 78°C, and treated with a tow in-feed roller pressure of 1.0 bar to 6.0 bar, more preferably about 2.0 bar, a crimping chamber pressure of 0.5 bar to 6.0 bar, more preferably 1.5 bar to 3.0 bar, and steam at 1.0 kg / min to 2.0 kg / min, more preferably 1.5 kg / min.

[0082] This can also be done at a temperature of no more than 130°C, provided that the smooth, or optionally crimped, fibers are relaxed and / or fixed in an oven or hot air stream.

[0083] To produce staple fibers, smooth, or optionally crimped, fibers are taken in, then cut, optionally hardened, and fed into a press roll as flakes. The staple fibers of the present invention are preferably cut in the relaxation of a downstream mechanical cutting unit. Cutting is optional for producing tow types. These tow types are fed into the roll uncut and pressed.

[0084] Insofar as the embodiments of the present invention show the crimped fibers, the degree of crimp is preferably at least 2 crimps (fiber curls) per cm, preferably at least 3 crimps per cm, more preferably 3 to 9.8 curls per cm, and most preferably 3.9 to 8.9 curls per cm. For applications in manufacturing woven webs, a crimp value of 5 to 5.5 curls per cm is most preferred. For wet-process manufacturing of woven webs, the degree of crimp may need to be adjusted on a case-by-case basis.

[0085] Woven webs can be manufactured from the fibers according to the present invention, which is also an object of the present invention. Based on the good dispersibility of the fibers according to the present invention, such woven webs are preferably produced by a wet process.

[0086] Therefore, the term “textile web” should be understood in its broadest sense within the context of this specification. A textile web can be any form produced according to a web-forming technique, including fibers according to the present invention. An example of such a textile web is a fleece, particularly a wet-laid fleece, which is made by thermal bonding and is preferably based on staple fibers.

[0087] The fibers according to the present invention also have good dispersion properties; that is, the fibers will maintain very good dispersion quality even after longer storage periods of several weeks or months, for example, in rolls or equivalent forms. Furthermore, the fibers according to the present invention have good long-term dispersion quality; that is, when the fibers are dispersed in a liquid medium, for example in water, the fibers will remain dispersed for a longer period and will only begin to settle after a longer period of time.

[0088] Test method: Unless otherwise stated in the above description, the following measurement or test methods shall be used.

[0089] Number: The thread count was determined according to DIN EN ISO 1973.

[0090] Dispersibility: To evaluate dispersion, the following test method was developed and applied according to the present invention.

[0091] The fibers according to the present invention are cut to a length of 2 mm to 12 mm. The cut fibers are placed in a glass container (dimensions: 150 mm long, 200 mm wide, 200 mm high) filled with DI water (DI = deionized) at room temperature (25°C). The amount of fiber is 0.25 g per liter of DI water. For better evaluation, typically 1 g of fiber and 4 liters of DI water are used.

[0092] Next, the fiber / DI water mixture is stirred for at least 3 minutes using a standard laboratory magnetic mixer (e.g., IKAMAG RCT) and a [sic magnetic fish] (80 mm) at a rotation speed of approximately 750 rpm to 1500 rpm, after which the mixer is switched off. Then, it is determined whether all the fibers have dispersed.

[0093] This dispersion behavior of the fibers is evaluated here as follows: Not dispersed (-) Partially distributed (o) Completely distributed (+) The above evaluation will be conducted based on predetermined time intervals.

[0094] biologically degradable The decision will be made in accordance with ASTM D5338-15 (Standard Test Method for Determining Aerobic Biodegradation of Plastic Materials Under Controlled Composting Conditions, Incorporating Thermophilic Temperatures, ASTM International, West Conshohocken, PA, 2015, www.astm.org).

[0095] Number average molecular weight (Mn) Determination by gel permeation chromatography or end-group titration for a narrowly distributed polystyrene standard.

[0096] Weight average molecular weight (Mw) Determination by gel permeation chromatography or end-group titration for a narrowly distributed polystyrene standard.

[0097] intrinsic viscosity The determination was made by GPC at a 0.1% polymer concentration in chloroform at 25°C.

[0098] Glass transition temperature and melting temperature Determination by dynamic differential scanning calorimetry (DSC) following the procedure below: Performing DSC measurements under nitrogen conditions and calibration for indium. Nitrogen flow rate is 50 ml / min; starting fiber weight is in the range of 2 mg to 3 mg.

[0099] Temperature range of -50°C to 210°C at 10K / min, followed by isothermal heating for 5 minutes, and finally back down to -50°C at 10K / min. The final temperature is generally always about 50°C higher than the expected maximum melting point. DSC measurements are performed using TA / Waters Modell Q100.

[0100] melt viscosity The melt viscosity was measured using Goettfert's Rheo Tester 1000 at a temperature of 190°C for 200 seconds. -1 (Shearing) and 1200s -1 It is determined by (shear).

[0101] Apparent viscosity The decision will be made as described in International Publication No. 2007 / 070064.

[0102] Meltflow Index The determination is made according to ASTM Test Method D1238-13 (ASTM D1238-13, Standard Test Method for Melt Flow Rates of Thermoplastics by Extrusion Plastometer, ASTM International, West Conshohocken, PA, 2013, www.astm.org). The melt flow index is the weight (in grams) of polymer that can be extruded through the opening (0.0825 inch diameter) of an extrusion rheometer when subjected to a force of 2160 grams for 10 minutes at 190°C.

[0103] Latent heat of fusion The latent heat of fusion (ΔHf), latent heat of crystallization (ΔHC), and crystallization temperature are measured by differential scanning calorimetry ("DSC") according to ASTM D-3418 (ASTM D3418-15, Standard Test Method for Transition Temperatures and Enthalpies of Fusion and Crystallization of Polymers by Differential Scanning Calorimetry, ASTM International, West Conshohocken, PA, 2015, www.astm.org).

[0104] Thermal shrinkage Twelve fibers (measurement samples) are extracted from the tow sample. Using tweezers, one end of each fiber is clamped to a multi-clamp, and a decrimping weight is attached to the other end. The measurement is obtained from a two-component fiber of type PLA / PBS (core / shell) with a count of 2.2 dtex, and the decrimping weight is 190 mg.

[0105] The multi-clamp with the sample attached is fixed to a stand, so that the sample hangs freely with a preload applied to the stand. The selected starting length (usually 150 mm) is marked on each fiber. This is done by marking lines on the stand and marking points on the sample. After marking, the attached multi-clamp is lowered and placed on a velvet sheet. There, the crimp removal weight is removed, and the free end of the fiber is clamped to a second multi-clamp. The sample, sandwiched between the two multi-clamps, is hung on a wire rack without tension. This wire rack is placed in the center of a shrink oven preheated to the correct processing temperature (standard temperatures are 200°C, 110°C, and 80°C). After a processing time of 5 minutes, the wire rack is removed from the oven. After the two multi-clamps have cooled, they are removed along with the sample and placed on a velvet sheet. After a 30-minute acclimatization time, a back measurement may be performed. For this purpose, the crimp-removing weight is reattached to the sample and hung on the stand. For the return measurement, the adjustable marking line on the stand is positioned so that the upper end of each marking point is covered by the marking line. Here, the length between the markings on the stand's counter is read individually for each fiber with an accuracy of 1 / 10 mm.

[0106] Calculation of length change: Change in length [%] = (Starting length [mm] - Measured length [mm]) / Starting length [mm] × 100%

[0107] The average value of all 12 measured samples is counted.

[0108] The present invention will be described below with reference to examples, but its scope is not limited thereto. [Examples]

[0109] NatureWorks' raw materials, PLA 6202D and BioPBS Fz71PM, were spun into corresponding fibers using two-component spinning technology. The PLA concentration as the core material was 70% by weight, and the shell proportion was 30% by weight.

[0110] A 4.0 dtex yarn count was obtained using an 827-hole nozzle and a set conveying rate of 331 g / min at a draw speed of 1000 m / min. Furthermore, at a spinning temperature of 240°C, an antioxidant at a concentration of 0.05% was added to the PBS to achieve the correspondingly good spinning behavior. As usual, the spun material was finished to allow for further processing.

[0111] Next, the spun product was processed on a conventional staple fiber line with an undrawn tow length of approximately 42 ktex.

[0112] The following textile techniques, which involve stretching in a 2.2 dtex vapor medium, fixing at 90°C in an air-circulating oven, and crimping, yielded values ​​important for further processing in the pneumatic procedure. Linear density: 2.3dtex Hardness: 28 cN / tec Stretching: 41% Shrinkage (110℃): 1.5% Crimp: 5Bg / cm

[0113] BioPBS Fz71PM is 200s -1 (Shear) 279 Pa·s and 1200 s -1 It is a polybutylene succinate with a melting viscosity of 139 Pa·s (at 190°C) under shear pressure.

[0114] PLA6202D has a viscosity of 1.24 g / cm³. 3 It is a polylactic acid with a relative density (according to ASTM D792) and a melt flow index in the range of 15 to 30 (g / 10 min at 210°C). The glass transition temperature is 55°C to 60°C (according to ASTM D3417), and the crystal melting temperature is 160°C to 170°C (according to ASTM D3418).

Claims

1. A two-component polymer fiber, wherein the fiber comprises component A (core) and component B (shell), (i) The melting point of the thermoplastic polymer in component A is at least 5°C higher than the melting point of the thermoplastic polymer in component B. (ii) A fiber material containing component A contains biopolymer A, and a fiber material containing component B contains biopolymer B. (iii) The biopolymer A is polylactic acid, and the biopolymer B is polybutylene succinate and / or polybutylene succinate copolymer. In a two-component polymer fiber, The two-component polymer fiber is such that biopolymer A and biopolymer B are each biologically degradable synthetic biopolymers according to ASTM D5338-15, and the two-component polymer fiber is spun in toe form and then stretched in a single step between draw frame S2 and draw frame S1, the temperature of the toe during stretching on draw frame S1 is 30°C to 80°C, and the temperature of the toe during stretching on draw frame S2 is 20°C to 35°C. The two-component polymer fiber is characterized in that, in its stretched form, it has a count of 0.5 dtex to 3 dtex, and its hot air shrinkage rate measured at 110°C is in the range of 0% to 10%, and crystallization is induced by exposure to steam during the stretching process.

2. The polymer fiber according to claim 1, characterized in that the biopolymer A is polylactic acid having a minimum number-average molecular weight (Mn) of 500 g / mol.

3. The polymer fiber according to claim 1 or 2, characterized in that the biopolymer A is polylactic acid having a number-average molecular weight (Mn) of up to 1,000,000 g / mol.

4. The polymer fiber according to claim 1, characterized in that the biopolymer A is polylactic acid having a weight-average molecular weight (Mw) in the range of 750 g / mol to 5,000,000 g / mol, and the polydispersity of these polymers is in the range of 1.5 to 5.

5. The polymer fiber according to one or more of claims 1 to 4, characterized in that the biopolymer A is polylactic acid having an intrinsic viscosity measured at 25°C in chloroform with a polymer concentration of 0.1% in the range of 0.5 dl / g to 8.0 dl / g.

6. The polymer fiber according to one or more of claims 1 to 5, characterized in that the biopolymer A has a glass transition temperature higher than 20°C.

7. The polymer fiber according to one or more of claims 1 to 6, characterized in that the biopolymer B has a number-average molecular weight (Mn) of at least 10,000 daltons and up to a maximum of 120,000 daltons.

8. The polymer fiber according to one or more of claims 1 to 7, characterized in that the biopolymer B has a weight-average molecular weight (Mw) of at least 50,000 daltons and up to a maximum of 240,000 daltons.

9. The polymer fiber according to one or more of claims 1 to 8, characterized in that the biopolymer B has a melt flow index of 5 grams to 200 grams per 10 minutes, as measured by the ASTM test method D1238-13.

10. The polymer fiber according to one or more of claims 1 to 9, characterized in that the biopolymer B has a glass transition temperature at least 5°C lower than the glass transition temperature of the biopolymer A.

11. The polymer fiber according to one or more of claims 1 to 10, characterized in that the polymer fiber is stretched after spinning in tow form, and the stretching is performed by exposure to steam at a stretch rate of 1.2 to 6.

0.

12. The polymer fiber according to claim 11, characterized in that the biopolymer B has a number-average molecular weight (Mn) of at least 10,000 daltons and up to a maximum of 30,000 daltons.

13. The aforementioned biopolymer B is 200s －１ (Shear) 250 Pa·s to 400 Pa·s and 1200 s －１ The polymer fiber according to claim 12, characterized in that it has a melt viscosity determined at a temperature of 190°C, in the range of 125 Pa·s to 190 Pa·s under shear.

14. A woven web comprising the polymer fibers described in claims 1 to 13.