High tenacity copolymer formulations

Abstract

Polyamide compositions containing amide monomer segments (e.g., PA6,6) and polyamide copolymer segments (e.g., PA6; PA6,10; PA6,12; or PA6,T; or combinations thereof), in which the polyamide composition contains at least 55 wt. % of amide monomer segments, based on the total number of segments in the polyamide composition. Fibers made from the polyamide composition demonstrate a tenacity greater than 3 grams per denier. These compositions can contain from 1 μeq / g to 80 μeq / g capped end groups from mono acid end capping agents. The polyamide compositions can be processed to form fibers with a linear mass density ranging from 20 denier to 2000 denier.

Description

HIGH TENACITY COPOLYMER FORMULATIONSTECHNICAL FIELD

[0001] The present disclosure relates to high tenacity polyamide compositions that have amide monomer segments and polyamide copolymer segments within the polyamide chains.CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of U.S. provisional application No. 63 / 655,688, filed on June 4, 2024, the entire contents of which are hereby incorporated by reference in this application.BACKGROUND

[0003] Polymer tenacity is a performance feature that contributes to product performance, durability, and safety. Tenacity refers to the ability of a material to withstand force without breaking or deforming. It plays an important role in several industrial applications, where strength and resilience are essential, such as aerospace, automotive, and construction. Additionally, higher tenacity enables the engineering of lighter and more efficient structures. For example, tenacity allows for the use of thinner and lighter materials without sacrificing strength, temperature resistance, and other key performance characteristics.

[0004] Drawing is a process that affects polymer fiber tenacity during manufacturing. As discussed herein, it has been found that when polymers are subjected to higher draw ratios during the extrusion process, their molecular alignment and orientation can be improved. This alignment leads to enhanced tensile strength, stiffness, and toughness, making the resultant material more suitable for a wide range of applications such as three-dimensional (3D) printing, textile manufacturing, composite production, airbag fabrics, tire cord, and many other fabric applications.

[0005] Improving tenacity and draw ratio simultaneously presents a challenge due to the trade-offs between these two properties. As these two properties compete with one another, it is challenging to find the right balance between maximizing molecular alignment for increased tenacity and avoiding excessive stretching that could lead to material degradation or decreased mechanical properties through drawing. Higher draw ratios may initially lead to increased molecular alignment and tenacity; however, it is important to balance flexibility (elongation at break) and processing yields.

[0006] U.S. Patent No. 10,836,863 discloses a copolyamide composition comprising a statistical copolyamide containing 70-99 weight percent (wt. %) of diamine and dicarboxylic acid repeat units and 1-30 wt. % of lactam or AA-BB repeat units, whereby incorporation of the comonomer lactam or AA-BB unit reduces the crystallization rate (longer crystallization times) while maintaining (1)high melting point, (2) low potential plate out, (3) low oxygen permeation, (4) high tensile strength and (5) puncture / tear resistance.

[0007] U.S. Patent No. 11,384,242 discloses a terpolymer composition that contains a statistical amount of 50-98 wt. % of a first repeating AA-BB comonomer unit; 1-25 wt. % of a second repeating AA-BB comonomer unit; and 1-25 wt. % of a repeating lactam comonomer unit or 1-25 wt. % of a third repeating AA-BB comonomer unit, where the terpolymer composition exhibits a high melting point similar to that of PA6,6 while also exhibiting a significantly reduced crystallization rate and crystallization temperature.

[0008] The need exists for polyamide compositions capable of achieving a balance between tenacity and draw ratio that provide for high tenacity of the final product.SUMMARY

[0009] Provided here are compositions and methods to address these shortcomings of the art and provide other additional or alternative advantages. The disclosure herein provides one or more embodiments of polyamide compositions containing amide monomer segments (e.g., PA6,6) and polyamide copolymer segments (e.g., PA6; PA6,10; PA6,12; or PA6,T; or combinations thereof). Certain embodiments include polyamide fibers containing a polyamide composition that includes at least 55 weight percent (wt. %) amide monomer segments, based on a total number of segments in the polyamide composition, and polyamide copolymer segments. In certain embodiments, the polyamide fiber has a tenacity greater than 3 grams per denier, as determined in accordance with ASTM D3822 (2018).

[0010] In some embodiments, the polyamide composition contains capped end groups ranging from 1 microequivalents per gram (p.eq / g) to 80 peq / g. In some embodiments, the capped end groups include a capping agent, such as acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid, octanoic acid, palmitic acid, myristic acid, decanoic acid, undecanoic acid, dodecanoic acid, oleic acid, or stearic acid, or any combinations thereof. In some embodiments, the polyamide composition contains polyamide copolymer segments, ranging from 10 wt. % to 45 wt. % based on the total number of segments in the polyamide composition. The polyamide copolymer segments include PA6; PA6,10; PA6,12; or PA6,T; or combinations thereof. In some embodiments, the polyamide composition contains at least 70 wt. % amide monomer segments and from 10 wt. % to 30 wt. % of the polyamide copolymer segments, based on the total number of segments in the polyamide composition. In these embodiments, the amide monomer segments contain PA6,6; and the polyamide copolymer segments contain PA6; PA6,10; PA6,12; or PA6,T; or combinations thereof.

[0011] In some embodiments, a draw ratio of the polyamide fiber is greater than 5, and the tenacity of the polyamide fiber is greater than 9 grams per denier, as determined in accordance with ASTM D3822 (2018). In some embodiments, the draw ratio of the polyamide fiber is at least 5.6, and the tenacity of the polyamide fiber is at least 10 grams per denier, as determined in accordance with ASTM D3822 (2018). In some embodiments, the polyamide composition demonstrates a time to fully crystallize greater than 10 seconds at a temperature ranging from 100 °C to 220 °C. In some embodiments, the polyamide composition contains less than 15 wt. % non-linear monomer segments, based on the total number of segments in the polyamide composition. In some embodiments, the polyamide composition does not contain (or is free of) isophthalic acid, meta- xylene diamine, or 2- methyl pentamethylene diamine segments. In some embodiments, the polyamide fiber has a linear mass density ranging from 20 denier (D) to 2000 D. In some embodiments, the polyamide fiber has an elongation at break of at least 18%, as determined in accordance with ASTM D3822 (2018).

[0012] Embodiments include methods for making a polyamide fiber. One such method includes preparing a polyamide composition containing at least 55 weight percent (wt. %) amide monomer segments, based on a total number of segments in the polyamide composition, and polyamide copolymer segments. This method includes melt spinning the polyamide composition, thereby to yield the polyamide fiber having a tenacity greater than 3 grams per denier, as determined in accordance with ASTM D3822 (2018).

[0013] In some embodiments, the method of preparing of the polyamide composition includes capping an amine end group of the polyamide composition with a capping agent. In some embodiments, the capping agent contains acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid, octanoic acid, palmitic acid, myristic acid, decanoic acid, undecanoic acid, dodecanoic acid, oleic acid, or stearic acid, or any combinations thereof. In some embodiments, the polyamide fiber has an elongation at break of at least 18%, as determined in accordance with ASTM D3822 (2018). In some embodiments, a process yield of the polyamide fiber is greater than 70%. In some embodiments, the polyamide composition contains from 10 wt. % to 45 wt. % of the polyamide copolymer segments, based on the total number of segments in the polyamide composition.

[0014] In some embodiments, the melt spinning of the polyamide composition includes drawing the polyamide composition using a draw ratio greater than 5, and wherein the tenacity of the polyamide fiber is greater than 9 grams per denier, as determined in accordance with ASTM D3822 (2018). In some embodiments, the draw ratio is at least 5.6, and the tenacity of the polyamide fiber is at least 10 grams per denier, as determined in accordance with ASTM D3822 (2018). In someembodiments, the polyamide fiber demonstrates a time to fully crystallize greater than 10 seconds at a temperature ranging from 100 °C to 220 °C.BRIEF DESCRIPTION OF THE DRAWINGS[00151 The accompanying drawings, which are included to provide a further understanding of the embodiments of the present disclosure, are incorporated in and constitute a part of this specification, illustrate embodiments of the present disclosure, and together with the detailed description, serve to explain principles of the embodiments discussed herein.

[0016] FIG. 1 is a graphical representation indicating tenacity as a function of draw ratio for example polyamide fiber compositions, according to an embodiment.

[0017] FIG. 2 is a graphical representation indicating tenacity and elongation at break as a function of draw ratio for three example polyamide fiber compositions.DETAILED DESCRIPTION

[0018] Reaching a high draw ratio to achieve high tenacity through a melt spinning process involves balancing tenacity and draw ratio, which is a known challenge in the industry, given the difficulty in attaining such high draw ratios without having line breaks, reduced elongation, and other issues. While increasing draw ratios during processing has been found to enhance molecular alignment and tenacity, it also risks process stability, yields, and elongation at break. Some other approaches to achieve a balance between tenacity and draw ratio include chemical crosslinking and addition of additives and fillers to the polyamide composition. However, these approaches all have their own drawbacks both from processing and performance perspectives.

[0019] Polyamide compositions that contain specific combinations of polyamide segments (that may be incorporated into the polymer chain) provide for a synergistic, desired balance between the draw ratio and high tenacity while also maintaining good temperature resistance, elongation, and other key performance factors. Specifically, by employing different types of polyamide copolymer segments and amide monomer segments, the chain packing of the polymers is advantageously altered, which, in turn, beneficially affects both the crystallization rate and draw ratio. As described herein, the use of the disclosed combinations of copolymer segments influences the arrangement of polymer chains in the solid state, which affects chain packing and crystallinity. If, however, the randomness of the copolymer segments causes too much disruption in chain packing, it will result in a material that has inferior mechanical properties. On the other hand, some randomness can beneficially affectchain alignment, which can result in a polyamide formulation with desirable crystallization rate while synergistically improving the draw ratio and maintaining the high tenacity of the polyamide.

[0020] Applicant has recognized that in certain embodiments, the capped end groups of polyamide compositions can have effects on the chemical and physical properties of the polyamide composition. Uncapped or unmodified polyamide generally has amine or carboxylic groups that appear at the chain ends. By capping the amine end groups (AEG) using a mono acid, it can advantageously affect various parameters during process, such as the composition’s viscosity and the molecular weight control. The benefits of the capped end groups include: (1) limiting extreme viscosity changes during processing, (2) reducing moisture level impact of viscosity, and (3) moderating relative viscosity or molecular weight build during solid state polymerization. By moderating and controlling viscosity build, the end user will have more consistency in the product.

[0021] Applicant has also found that polyamide copolymer segments beneficially affect the nucleation and growth of crystalline regions during crystallization. Some irregular or random polyamide copolymer structures may lead to heterogeneous nucleation and less ordered crystallization due to the presence of different monomer units and chain configurations, which, in turn, can result in a higher draw ratio. Homopolymer structures with well-defined monomer sequences, on the other hand, may promote homogeneous nucleation and ordered crystalline growth, which, in turn, result in a lower draw ratio.

[0022] Through careful research and molecular design, Applicant has surprisingly found that the incorporation of the disclosed polyamide copolymer segments (along with the amide monomer segments) beneficially affect the crystallization rate of the resulting composition. This results in longer crystallization times (compared to compositions that contain only amide monomer segments), while maintaining the other advantages of the amide monomer segments, such as, superior elongation properties, tenacity, and draw ratio.

[0023] Polyamide composition

[0024] Polyamide compositions disclosed herein contain amide monomer segments (e.g., PA6,6) and polyamide copolymer segments (e.g., PA6,12). In some embodiments, the polyamide composition contains at least 30 wt. % of amide monomer segments, based on the total number of segments in the polyamide composition. In some embodiments, the polyamide composition contains at least 55 wt. % or at least 70 wt. % of amide monomer segments, based on the total number of segments in the polyamide composition. Certain embodiments of the fibers made from the polyamide composition demonstrate a tenacity greater than 3 grams per denier. Certain embodiments of the fibersmade from the polyamide composition demonstrate a tenacity greater than greater than 9 grams per denier.

[0025] Amide monomer segments

[0026] In some embodiments, the amide monomer segments are prepared from dicarboxylic acid (diacid) and diamine building blocks. The polyamide copolymer segments can be prepared from a lactam, or from diacid and diamine that are different from the ones in the amide monomer segments, or combinations thereof.

[0027] In some embodiments, the polyamide compositions contain linear monomer segments. Linear monomer segments refer to the segments in a polymer chain do not have any side chain, branching, and / or aromatic structures. The linear monomer segments can be from the amide monomer segments, the polyamide copolymer segments, or combinations thereof.

[0028] In some embodiments, the polyamide composition contains greater than 30 wt. % of the amide monomer segments, based on the total number of segments in the polyamide composition (e.g., greater than 35 wt. %, greater than 40 wt. %, greater than 45 wt. %, greater than 50 wt. %, greater than 55 wt. %, greater than 60 wt. %, greater than 65 wt. %, greater than 70 wt. %, greater than 75 wt. %, greater than 80 wt. %, greater than 85 wt. %, greater than 90 wt. %, or greater than 95 wt. %). In terms of ranges, the polyamide composition may contain from 30 wt. % to 99 wt. % of the amide monomer segments, based on the total number of segments in the polyamide composition (e.g., from 40 wt. % to 95 wt. %, from 50 wt. % to 95 wt. %, from 60 wt. % to 95 wt. %, from 62 wt. % to 95 wt. %, from 65 wt. % to 95 wt. %, from 68 wt. % to 95 wt. %, from 70 wt. % to 95 wt. %, from 70 wt. % to 80 wt. %, from 70 wt. % to 90 wt. %, from 75 wt. % to 95 wt. %, or from 75 wt. % to 90 wt. %). In terms of upper limit, the polyamide composition may contain less than 99 wt. % of the amide monomer segments, based on the total number of segments in the polyamide composition (e.g., less than 95 wt. %, less than 90 wt. %, less than 85 wt. %, less than 90 wt. %, less than 75 wt. %, less than 70 wt. %, less than 65 wt. %, less than 60 wt. %, less than 55 wt. %, less than 50 wt. %, less than 45 wt. %, or less than 40 wt. %).

[0029] In some embodiments, the polyamide composition contains greater than 50 wt. % of the amide monomer segments, based on the total number of segments in the polyamide composition (e.g., greater than 55 wt. %, greater than 60 wt. %, greater than 65 wt. %, greater than 70 wt. %, greater than 75 wt. %, greater than 80 wt. %, greater than 85 wt. %, greater than 90 wt. %, or greater than 95 wt. %). In terms of ranges, the polyamide composition may contain from 50 wt. % to 99 wt. % of the amide monomer segments, based on the total number of segments in the polyamide composition (e.g., from 50 wt. % to 95 wt. %, from 60 wt. % to 95 wt. %, from 62 wt. % to 95 wt. %, from 65 wt. % to95 wt. %, from 68 wt. % to 95 wt. %, from 70 wt. % to 95 wt. %, from 70 wt. % to 80 wt. %, from 70 wt. % to 90 wt. %, from 75 wt. % to 95 wt. %, or from 75 wt. % to 90 wt. %). In terms of upper limit, the polyamide composition may contain less than 99 wt. % of the amide monomer segments, based on the total number of segments in the polyamide composition (e.g., less than 95 wt. %, less than 90 wt. %, less than 85 wt. %, less than 90 wt. %, less than 75 wt. %, less than 70 wt. %, less than 65 wt. %, less than 60 wt. %, less than 55 wt. %).

[0030] In some embodiments, the polyamide composition contains at least 70 wt. % of the amide monomer segments, based on the total number of segments in the polyamide composition (e.g., greater than 72 wt.%, greater than 75 wt.%, greater than 78 wt. %, greater than 80 wt. %, greater than 82 wt. %, greater than 85 wt. %, greater than 88 wt. %, greater than 90 wt. %, greater than 92 wt. %, greater than 95 wt. %, greater than 98 wt. %, or greater than 99 wt. %). In terms of ranges, the polyamide composition may contain from 70 wt. % to 99 wt. % (e.g., from 70 wt. % to 99 wt.%, from 75 wt. % to 98 wt. %, from 78 wt. % to 98 wt. %, from 80 wt. % to 98 wt. %, from 80 wt. % to 95 wt. %, from 80 wt. % to 90 wt. %, from 85 wt. % to 98 wt. %, from 88 wt. % to 98 wt. %, and from 85 wt. % to 95 wt. %).

[0031] In some embodiments, the diacid includes linear aliphatic diacids, such as pimelic acid, adipic acid, suberic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brassylic acid, tetradecanedioic acid, hexadecanedioic acid, and / or octadecanedioic acid. The diacid can also include terephthalic acid, 1,4-cyclohexane dicarboxylic acid, and / or 2,6-napthalene dicarboxylic acid, and may include anhydrides of any of the aforementioned diacids.

[0032] In some embodiments, the diamine includes linear aliphatic diamines, such as 1,5- diaminopentane, 1,6-diaminohexane, l,9-nonanediamine,l,10-diaminodecane; 1,11- diaminoundecane; 1,12-diaminododecane; 1,13-diaminotridecane; 1,14-diaminotetradecane; 1,16- diaminohexadecane; and / or 1,18-diaminooctadecane.

[0033] In some embodiments, the lactam includes aliphatic cyclic lactams, such as butyrolactam, valerolactam, s-caprolactam, enantiolactam, capryllactam laurolactam, 12-aminodoecanolactam, and / or 2-azacyclononone.

[0034] In certain embodiments, the diamine and diacid building blocks for the amide monomer segments are hexamethylene diamine and adipic acid to provide PA6,6; and the polyamide copolymer segments are from caprolactam, which allows the incorporation of PA6 into the PA6,6. Thus, the polyamide composition is a combination of PA6,6 segments and PA6 segments.

[0035] In some embodiments, the amide monomer segments include PA4,T; PA5,T; PA6; PA6,6; PA6,T; PA6,10; PA10,T; PA6,12; PA10,6; PA9,T; PA12,T; PA12; PA11; and copolymers, blends, mixtures and / or other combinations thereof.

[0036] In some embodiments, the polyamide composition contains less than 15 wt. % of non-linear monomer segments, based on the total number of segments in the polyamide composition, (e.g., less than 15 wt. %, less than 13 wt. %, less than 10 wt. %, less than 9 wt. %, less than 8 wt. %, less than 7.5 wt. %, less than 7 wt. %, less than 6.5 wt. %, less than 6 wt. %, less than 5 wt. %, less than 4.5 wt. %, less than 4 wt. %, less than 3 wt. %, less than 2.5 wt. %, less than 2 wt. %, or less than 1 wt. %).

[0037] Polyamide copolymer segments

[0038] The polyamide compositions also contain polyamide copolymer segments. In some embodiments, the polyamide composition contains from 10 wt. % to 70 wt. % of the polyamide copolymer segments, based on the total number of segments in the polyamide composition (e.g., from 15 wt. % to 60 wt. %, from 15 wt. % to 50 wt. %, from 20 wt. % to 45 wt. %, from 20 wt. % to 30 wt. %, from 30 wt. % to 45 wt. %, from 25 wt. % to 40 wt. %, from 30 wt. % to 40 wt. %, or from 30 wt. % to 37 wt. %). In terms of upper limits, the polyamide copolymer segments concentration can be less than 70 wt. % (e.g., less than 65 wt. %, less than 60 wt. %, less than 55 wt. %, less than 50 wt. %, less than 45 wt. %, less than 40 wt. %, or less than 37 wt. %). In terms of lower limits, the polyamide copolymer segments concentration can be greater than 10 wt. % (e.g., greater than 15 wt. %, greater than 20 wt. %, greater than 25 wt. %, greater than 27 wt. %, greater than 30 wt. %, or greater than 31 wt. %). In some embodiments, higher concentrations (e.g., greater than 70 wt. %) and lower concentrations (e.g., less than 10 wt. %) may also be used.

[0039] In some embodiments, the polyamide composition includes from 30 wt. % to 50 wt. % of the polyamide copolymer segments, based on the total number of segments in the polyamide composition (e.g., from 30 wt. % to 45 wt. %, from 35 wt. % to 45 wt. %, from 35 wt. % to 50 wt. %, from 30 wt. % to 40 wt. %, or from 35 wt. % to 40 wt. %). In terms of upper limits, the semi-crystalline polyamide concentration can be less than 50 wt. % (e.g., less than 45 wt. %, less than 40 wt. %, less than 35 wt. %, or less than 31 wt. %). In terms of lower limits, the semi-crystalline polyamide concentration can be greater than 30 wt. % (e.g., greater than 35 wt. %, greater than 40 wt. %, greater than 45 wt. %, or greater than 49 wt. %). In some embodiments, higher concentrations (e.g., greater than 50 wt. %) and lower concentrations (e.g., less than 30 wt. %) may be used.

[0040] In some embodiments, the polyamide composition contains from 10 wt. % to 45 wt. % of the polyamide copolymer segments, based on the total number of segments in the polyamidecomposition (e.g., from 10 wt. % to 30 wt.%, from 15 wt. % to 40 wt. %, from 15 wt. % to 35 wt. %, from 20 wt. % to 30 wt. %). In terms of upper limits, the polyamide copolymer segments concentration can be less than 50 wt. % (e.g., less than 45 wt. %, less than 40 wt. %, less than 35 wt. %, less than 30 wt. %). In terms of lower limits, the polyamide copolymer segments concentration can be greater than 10 wt. % (e.g., greater than 15 wt. %, greater than 20 wt. %, greater than 25 wt. %, greater than 30 wt. %, greater than 35 wt. %, or greater than 40 wt. %). In some embodiments, higher concentrations (e.g., greater than 45 wt. %) and lower concentrations (e.g., less than 10 wt. %) may also be used.

[0041] In some embodiments, the polyamide copolymer segments include one or more of PA4,T; PA5,T; PA6; PA6,6; PA6,T; PA6,10; PA10,T; PA6,12; PA10,6; PA9,T; PA12,T; PA12; PAH; and copolymers, blends, mixtures and / or other combinations thereof.

[0042] In an example embodiment, the polyamide composition contains at least 55 wt. % of the amide monomer segments (e.g., PA6,6), and from 10 wt.% to 45 wt.% of the polyamide copolymer segments, in which the polyamide copolymer segments include PA4,T; PA5,T; PA6; PA6,6; PA6,T; PA6,10; PA10,T; PA6,12; PAID, 6; PA9,T; PA12,T; PA12; PAH; or combinations thereof.

[0043] In an example embodiment, the polyamide composition contains at least 70 wt. % of the amide monomer segments (e.g., PA6,6), and from 10 wt.% to 30 wt.% of the polyamide copolymer segments, in which the polyamide copolymer segments include PA4,T; PA5,T; PA6; PA6,6; PA6,T; PA6,10; PA10,T; PA6,12; PA10,6; PA9,T; PA12,T; PA12; PA11; or combinations thereof.

[0044] In some embodiments, the polyamide composition does not contain or excludes non-linear diacids (e.g., isophthalic acid, meta-xylene diamine, and / or 2-methyl pentamethylene diamine segments).

[0045] In some embodiments, the polyamide composition contains less than 1 wt. % of non-linear diacid (e.g., isophthalic acid, and / or 2-methyl pentamethylene diamine segments), such as, less than 0.9 wt. %, less than 0.8 wt. %, less than 0.7 wt. %, less than 0.6 wt. %, less than 0.5 wt. %, less than 0.4 wt. %, less than 0.3 wt. %, less than 0.2 wt. %, or less than 0.1 wt. %.

[0046] Capped Polyamide Composition

[0047] In some embodiments, the polyamide composition contains polyamides with capped end groups. The term “capped end groups” refers to the amine end group (AEG) of the polyamide composition having been partially or fully capped (modified to change functionality) by a capping agent.

[0048] In some embodiments, the polyamide composition contains from 100 parts per million (ppm) to 5000 ppm capped end groups (e.g., from 300 ppm to 4500 ppm, from 300 ppm to 4000 ppm,from 300 ppm to 3000 ppm, from 300 ppm to 2500 ppm, from 300 ppm to 2250 ppm, from 300 ppm to 2000 ppm, from 400 ppm to 4000, from 400 ppm to 3500 ppm, from 400 ppm to 3000 ppm, from 400 ppm to 2500 ppm, from 400 ppm to 2000 ppm, from 500 ppm to 4000 ppm, from 500 ppm to 3500 ppm, from 500 ppm to 3000 ppm, from 500 ppm to 2500 ppm, from 500 ppm to 2000 ppm, or from 500 ppm to 1500 ppm). In terms of upper limit, the polyamide composition includes less than 5000 ppm capped end groups (e.g., less than 4500 ppm, less than 4000 ppm, less than 3500 ppm, less than 3000 ppm, less than 2500 ppm, less than 2000 ppm, less than 1500 ppm, less than 1200 ppm, less than 1000 ppm, less than 800 ppm, less than 700 ppm, less than 600 ppm, less than 500 ppm, less than 400 ppm, or less than 350 ppm). In terms of lower limit, the polyamide composition contains greater than 300 ppm capped end groups (e.g., greater than 350 ppm, greater than 400 ppm, greater than 500 ppm, greater than 600 ppm, greater than 700 ppm, greater than 800 ppm, greater than 1000 ppm, greater than 1200 ppm, greater than 1500 ppm, greater than 2000 ppm, greater than 2500 ppm, greater than 3000 ppm, greater than 3500 ppm, greater than 4000 ppm, or greater than 4500 ppm).

[0049] The capped polyamide may have from 1 peq / g to 80 peq / g capped end groups (e.g., from 5 peq / g to 75 peq / g, from 10 peq / g to 70 peq / g, from 15 peq / g to 65 peq / g, from 20 peq / g to 60 peq / g, from 25 peq / g to 55 peq / g, from 10 peq / g to 30 peq / g, from 30 peq / g to 50 peq / g, or from 35 peq / g to 45 peq / g). In terms of upper limits, the capped end group may be less than 80 peq / g (e.g., less than 75 peq / g, less than 70 peq / g, less than 65 peq / g. less than 69 peq / g, less than 55 peq / g, less than 50 peq / g, less than 45 peq / g, less than 40 peq / g, less than 30 peq / g, or less than 20 peq / g). In terms of lower limits, the capped end group may be greater than 1 peq / g (e.g., greater than 5 peq / g, greater than 10 peq / g, greater than 15 peq / g, greater than 20 peq / g, greater than 25 peq / g, greater than 30 peq / g, or greater than 35 peq / g).

[0050] In some embodiments, the capping is through an amidation reaction, and the capping agent includes a mono acid. Exemplary (mono) acids include, but are not limited to, acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid, octanoic acid, palmitic acid, myristic acid, decanoic acid, undecanoic acid, dodecanoic acid, oleic acid, or stearic acid, or any combinations thereof.

[0051] After capping, the AEG content of the polyamide composition may be calculated by titrating a sample with HC1. The concentration is then calculated as shown below in Equation 1.

[0052] Equation 1:[End Point ml x Normality HCl meq / mL x 1000 ueq / meq] - Blank ueq Sample weight (g)

[0053] Example Combinations

[0054] In some embodiments, the amide monomer segment contains PA6,6 and the polyamide copolymer segments include PA6; PA6,10; PA6,12; PA6,T; or combinations thereof. Exemplary polyamide compositions include PA6,6 / 6,T / 6; PA6,6 / 6,10; PA6,6 / 6,12; PA6,6 / 6,T; PA6,6 / 6; PA6,12 / 6,T; and PA6, 10 / 6, T.

[0055] In some embodiments, combining the amide monomer segments and polyamide copolymer segments may result in a beneficial relative viscosity (RV) of the polyamide composition. In some embodiments, the RV of the polyamide composition ranges from 5 to 100 (e.g., from 5 to 95, from 10 to 90, from 30 to 90, from 40 to 90, from 40 to 100, from 50 to 95, from 60 to 95, from 70 to 95, from 75 to 90, or from 80 to 90). In terms of lower limits, the RV of the polyamide composition may be greater than 5 (e.g., greater than 10, greater than 15, greater than 20, greater than 25, greater than 30, greater than 35, greater than 40, greater than 45, greater than 50, greater than 55, greater than 60, greater than 65, greater than 70, greater than 75, greater than 80, greater than 85, greater than 90, greater than 95, or greater than 99). In terms of upper limits, the RV of the polyamide composition may be less than 100 (e.g., less than 95, less than 90, less than 85, less than 80, less than 75, less than 70, less than 65 less than 60, less than 50, less than 40 less than 30, less than 20, less than 10, or less than 5). In some embodiments, higher RV (e.g., greater than 100) and lower RV (e.g., less than 5) may alternatively be used.

[0056] To calculate RV, a polymer may be dissolved in a solvent (usually formic or sulfuric acid), the viscosity is measured, then the viscosity is compared to the viscosity of the pure solvent. This yields a unitless measurement. Solid materials, as well as liquids, may have a specific RV. The fibers produced from the polyamide compositions may have the aforementioned relative viscosities, as well.

[0057] Other additives

[0058] In some embodiments, the polyamide composition can optionally include one or more additive(s). In some embodiments, the additives include one or more of catalyst, polymers other than polyamide, adhesion promoters, ions, compounds, preservatives, heat stabilizers, antioxidants, lubricants, flow enhancers, or other ingredients as known in the art. The additive(s) may include one or more of: inorganic stabilizers, organic stabilizers, flame retardants, lubricants, dyes, pigments, nucleating agents, metal flakes, impact modifiers, antistatic agents, conductivity additives, mold-release agents, optical brighteners, adhesion promoters, ageing inhibitors, antioxidants, antiozonants, light stabilizers, ultraviolet (UV) stabilizers, UV absorbers, UV blockers, inorganic heat stabilizers, organic heat stabilizers, processing aids, crystallization accelerators, crystallization retarders, flow aids, or reinforcing agents (e.g., fibrous materials and particulate fillers).

[0059] In some embodiments, the polyamide composition includes one or more heat stabilizers. The one or more heat stabilizers of the polyamide composition can be selected to improve performance, for example, at higher operating temperatures, without significantly negatively affecting the strength or other thermal properties of the material. At least one of the heat stabilizers of the polyamide composition can include copper. In some embodiments, all the heat stabilizers of the polyamide composition include copper. Copper stabilizers suitable for use as components of the polyamide composition include copper halides (e.g., chlorides, bromides, or iodides, or combinations thereof). Copper stabilizers can also include copper cyanide, copper oxide, copper sulfate, copper phosphate, copper acetate, copper propionate, copper benzoate, copper adipate, copper terephthalate, copper isophthalate, copper salicylate, copper nicotinate, copper stearate, or copper complex salts coordinated to a chelating amine (e.g., ethylenediamine and ethylenediaminetetraacetic acid), or combinations thereof.

[0060] In some embodiments, the polyamide composition includes from 10 ppm to 500 ppm copper (e.g., from 10 ppm to 400 ppm, from 20 ppm to 400 ppm, from 20 ppm to 350 ppm, from 20 ppm to 300 ppm, from 30 ppm to 400 ppm, from 30 ppm to 350 ppm, from 30 ppm to 300 ppm, from 40 ppm to 400 ppm, from 40 ppm to 350 ppm, from 40 ppm to 300 ppm, from 40 ppm to 250 ppm, from 40 ppm to 200 ppm, from 40 ppm to 150 ppm, from 40 ppm to 100 ppm, from 50 ppm to 250 ppm, from 50 ppm to 200 ppm, from 50 ppm to 150 ppm, from 50 ppm to 100 ppm, or from 50 ppm to 80 ppm). In terms of upper limit, the polyamide composition includes less than 500 ppm copper (e.g., less than 480 ppm, less than 450 ppm, less than 400 ppm, less than 350 ppm, less than 300 ppm, less than 250 ppm, less than 200 ppm, less than 150 ppm, less than 100 ppm, less than 80 ppm, less than 70 ppm, less than 60 ppm, less than 50 ppm, less than 40 ppm, less than 30 ppm, less than 20 ppm, or less than 10 ppm). In terms of lower limit, the polyamide composition includes greater than 10 ppm copper (e.g., greater than 15 ppm copper, greater than 20 ppm copper, greater than 25 ppm copper, greater than 30 ppm copper, greater than 40 ppm copper, greater than 50 ppm copper, greater than 60 ppm copper, greater than 70 ppm copper, greater than 80 ppm copper, greater than 90 ppm copper, greater than 100 ppm copper, greater than 150 ppm copper, greater than 200 ppm copper, greater than 250 ppm copper, greater than 300 ppm copper, greater than 350 ppm copper, greater than 400 ppm copper,or greater than 450 ppm copper). In some embodiments, higher amounts, (e.g., greater than 500 ppm) and lower amounts (e.g., less than 10 ppm) may alternatively be used.

[0061] In some embodiments, the combined concentration of the heat stabilizers of the polyamide composition ranges from 0.1 wt. % to 2 wt. % (e.g., from 0.1 wt. % to 0.6 wt. %, from 0.13 wt. % to 0.81 wt. %, from 0.18 wt. % to 1.1 wt. %, from 0.25 wt. % to 1.5 wt. %, or from 0.33 wt. % to 2 wt. %). In terms of upper limits, the heat stabilizer concentration can be less than 2 wt. % (e.g., less than 1.5 wt. %, less than 1.1 wt. %, less than 0.81 wt. %, less than 0.6 wt. %, less than 0.45 wt. %, less than 0.33 wt. %, less than 0.25 wt. %, less than 0.18 wt. %, or less than 0.13 wt. %). In terms of lower limits, the heat stabilizer concentration can be greater than 0.1 wt. % (e.g., greater than 0.13 wt. %, greater than 0.18 wt. %, greater than 0.25 wt. %, greater than 0.33 wt. %, greater than 0.45 wt. %, greater than 0.6 wt. %, greater than 0.81 wt. %, greater than 1.1 wt. %, or greater than 1.5 wt. %). In some embodiments, higher concentrations (e.g., greater than 2 wt. %) and lower concentrations (e.g., less than 0.1 wt. %) may alternatively be used.

[0062] In some embodiments, the polyamide composition includes one or more lubricants selected to serve as processing aids. The type and relative amount of lubricant can be selected to improve processing of the polyamide composition, and to contribute to the high strength of the material. In some embodiments, the lubricant includes a wax. In some embodiments, the lubricant consists of a wax. In some embodiments, the wax includes a fatty acid. In some embodiments, the lubricant consists of a fatty acid. In some embodiments, the wax includes a saturated fatty acid. In some embodiments, the lubricant consists of a saturated fatty acid. In some embodiments, the wax includes stearic acid, behenic acid, or salts or combinations thereof. In some embodiments, the lubricant consists of stearic acid, behenic acid, or salts or combinations thereof. The stearate lubricant can include, for example, zinc stearate calcium stearate, aluminum distearate, zinc stearate, and / or calcium stearate.

[0063] In some embodiments, the combined concentration of the one or more lubricants of the polyamide composition ranges from 0.1 wt. % to 2 wt. % (e.g., from 0.1 wt. % to 0.6 wt. %, from 0.13 wt. % to 0.81 wt. %, from 0.18 wt. % to 1.1 wt. %, from 0.25 wt. % to 1.5 wt. %, or from 0.33 wt. % to 2 wt. %). In terms of upper limits, the lubricant concentration can be less than 2 wt. % (e.g., less than 1.5 wt. %, less than 1.1 wt. %, less than 0.81 wt. %, less than 0.6 wt. %, less than 0.45 wt. %, less than 0.33 wt. %, less than 0.25 wt. %, less than 0.18 wt. %, or less than 0.13 wt. %). In terms of lower limits, the lubricant concentration can be greater than 0.1 wt. % (e.g., greater than 0.13 wt. %, greater than 0.18 wt. %, greater than 0.25 wt. %, greater than 0.33 wt. %, greater than 0.45 wt. %, greater than 0.6 wt. %, greater than 0.81 wt. %, greater than 1.1 wt. %, or greater than 1.5 wt. %). Insome embodiments, higher concentrations (e.g., greater than 2 wt. %) and lower concentrations (e.g., less than 0.1 wt. %) may alternatively be used.

[0064] In some embodiments, the polyamide composition includes one or more reinforcing agents, such as mineral reinforcements or fiber reinforcements or a combination thereof. The reinforcing agents can be selected to further enhance the strength characteristics of the polyamide composition without compromising the desired compositional thermal properties. The material of the filler is not particularly limited and may be selected from polyamide fillers known in the art. By way of nonlimiting example, the filler may include glass fibers and / or carbon fibers, particulate fillers, such as mineral fillers based on natural and / or synthetic layer silicates, talc, mica, silicate, quartz, titanium dioxide, wollastonite, kaolin, amorphous silicic acids, magnesium carbonate, magnesium hydroxide, chalk, lime, feldspar, barium sulphate, KEVLAR® fiber, basalt fiber, solid or hollow glass balls or ground glass, permanently magnetic or magnetizable metal compounds and / or alloys, and / or any combinations of these materials.

[0065] In some embodiments, the combined concentration of the reinforcing agents of the polyamide composition ranges from 15 wt. % to 60 wt. % (e.g., from 15 wt. % to 42 wt. %, from 19.5 wt. % to 46.5 wt. %, from 24 wt. % to 51 wt. %, from 28.5 wt. % to 55.5 wt. %, or from 33 wt. % to 60 wt. %). In terms of upper limits, the reinforcing agent concentration can be less than 60 wt. % (e.g., less than 55.5 wt. %, less than 51 wt. %, less than 46.5 wt. %, less than 42 wt. %, less than 37.5 wt. %, less than 33 wt. %, less than 28.5 wt. %, less than 24 wt. %, or less than 19.5 wt. %). In terms of lower limits, the reinforcing agent can be greater than 15 wt. % (e.g., greater than 19.5 wt. %, greater than 24 wt. %, greater than 28.5 wt. %, greater than 33 wt. %, greater than 37.5 wt. %, greater than 42 wt. %, greater than 46.5 wt. %, greater than 51 wt. %, or greater than 55.5 wt. %). In some embodiments, higher concentrations (e.g., greater than 60 wt. %) and lower concentrations (e.g., less than 15 wt. %) may alternatively be used.

[0066] In some embodiments, the polyamide composition contains a nucleating agent, such as talc, sodium benzoate, sodium or potassium salts of carboxylic acids, aluminum oxide, carbon nanotubes, zinc oxide, titanium dioxide, sodium bicarbonate, boron nitride, calcium carbonate, barium sulfate, calcium phosphate, calcium fluoride, sodium fluoride, sodium chloride, sodium sulfate, and / or BRUGGOLEN® P22.

[0067] In other embodiments, the polyamide composition is a “neat” composition, meaning that the polyamide composition contains little or no filler. For example, the polyamide compositions may contain less than 20 wt. % filler (e.g., less than 17 wt. %, less than 15 wt. %, less than 10 wt. %, or less than 5 wt. %). In terms of ranges, the polyamide compositions may contain from 0.01 wt. % to20 wt. % filler (e.g., from 0.1 wt. % to 15 wt. % or from 0.1 wt. % to 5 wt. %). In such embodiments, the amounts of other components may be adjusted accordingly based on the aforementioned component ranges and limits. In some embodiments, the concentration of the other components of the polyamide composition may be adjusted in light of the inclusion or exclusion of a glass filler.

[0068] Example Process Conditions

[0069] Embodiments include processes of making fibers from the polyamide compositions disclosed herein. One such process includes processing the amide monomer segments and the polyamide copolymer segments. The amide monomer segments and the polyamide copolymer segments can be any of those disclosed herein. In some embodiments, the polyamide composition contains at least 55 wt. % of amide monomer segments (e.g., PA6,6), based on the total number of segments in the polyamide composition; in which fibers made from the polyamide composition demonstrate a tenacity greater than 3 grams per denier. For example, certain embodiments of the polyamide composition contain at least 70 wt. % of amide monomer segments (e.g., PA6,6), based on the total number of segments in the polyamide composition.

[0070] Making polymer fibers and films differ from each in various aspects. Fiber manufacturing involves extrusion followed by drawing to align polymer chains and enhance strength, resulting in long, thin strands. On the other hand, film manufacturing involves extrusion or casting, often without the drawing step, yielding flat sheets. While fibers undergo a process of stretching to orient their structure, films may undergo calendering for thickness uniformity.

[0071] In some embodiments, the processing includes end-capping the polyamide composition with a mono acid. The types of mono acids that can be used for end-capping have been previously described. In some embodiments, the processing includes drawing, spinning, and / or blowing the polyamide composition.

[0072] The draw ratio is a parameter in the processing of polymer fibers that represents the ratio of the final length of a material to its original length after it has been mechanically drawn or stretched during manufacturing. This drawing process aligns the polymer chains through molecular orientation, enhancing the mechanical properties of the material, such as strength, stiffness, and tenacity. The disclosed compositions provide the ability to operate at preferred draw ratios, unlike conventional composition, which cannot be processed at the same draw ratios.

[0073] For molecular orientation, increasing the draw ratio enhances the orientation of the polymer chains along the axis of the fiber. This orientation reduces the amorphous regions in the polymer and increases the crystalline regions, resulting in polymers that are stronger and stiffer.

[0074] For mechanical strength and tenacity, higher draw ratios can improve the tenacity of fibers. Here, the polymer chains are more aligned and can better resist external loads, making the fibers stronger.

[0075] In terms of elasticity and modulus, as the draw ratio increases, the material can become less elastic but have a higher modulus (stiffness), which is beneficial in applications requiring dimensional stability under stress.

[0076] In some embodiments, the processing is conducted at a draw ratio ranging from 2 to 10 (e.g., from 3 to 10, from 4 to 10, from 4 to 9, from 4.7 to 10, from 4.7 to 9, from 4.7 to 8, from 4.7 to 7, from 5 to 10, from 5 to 9, from 5 to 8, from 5 to 7, 5.5 to 10, from 5.5 to 9, from 5.5 to 8, from 5.5 to 7, 6 to 10, from 6 to 9, from 6 to 8, from 6 to 7, 6.5 to 10, from 6.5 to 9, or from 6.5 to 8). In terms of lower limit, the draw ratio can be greater than 2 (e.g., greater than 3, greater than 4, greater than 4.6, greater than 4.8, greater than 5, greater than 5.1, greater than 5.5, greater than 5.6, greater than 5.8, greater than 6, greater than 6.2, greater than 7, greater than 8, or greater than 9).

[0077] In some embodiments, the various draw ratios between each of the godet rolls in the process can be spread out and so that the total draw ratio between any two sets of rolls is lower. Applicant recognized that this aspect can also improve the runnability of the fiber during the drawing process. For example, the 420 denier examples discussed herein (Tables 1 and 2) were prepared using five sets of godet roles, while the 1260 denier examples discussed herein (Table 3) were prepared using six sets of godet roles. In some embodiments, the godet roll ratio between the fifth and first godet rolls, which may correspond to the total or final draw ratio, may range from 4 to 7. In some embodiments, the godet roll ratio between the second and first godet rolls may range from 1 to 1.2. In some embodiments, the godet roll ratio between the third and second godet rolls, which may correspond to a first or initial draw ratio, may range from 2 to 3. In some embodiments, the godet roll ratio between the fourth and third godet rolls may range from 1 to 1.5. In some embodiments, the godet roll ratio between the fifth and fourth godet rolls may range from 1.25 to 1.75. In some embodiments, the godet roll ratio between the sixth and fifth godet rolls, which may correspond to relaxation of the fiber, may range from 0.75 to 1.25.

[0078] In some embodiments, a pre- stretch draw may be used to pull out some of the tension before the fiber is exposed to the higher draw ratios in the drawing process. This pre-stretch draw can be used to improve runnability by increasing the pre-stretch to a point where the number of broken filaments that occur in the drawing process arc reduced significantly. In some embodiments, the prestretch draw ratio may range from 1.00 to 1.20.

[0079] In some embodiments, the fibers made from the polyamide composition have a linear mass density (sometimes simply referred to as the “denier” of the polyamide composition) ranging from 20 D to 2000 D (e.g., from 20 D to 600 D, from 50 D to 600 D, from 100 D to 600 D, from 150 D to 600 D, from 200 D to 600 D, from 250 D to 600 D, from 200 D to 550 D, from 200 D to 500 D, from 250 D to 550 D, from 250 D to 500 D, from 300 D to 600 D, from 300 D to 550 D, from 300 D to 500 D, from 400 D to 600 D, from 400 D to 550 D, from 400 D to 500 D, from 600 D to 1900 D, from 600 D to 1800 D, from 600 D to 1700 D, from 600 D to 1600 D, from 700 D to 1900 D, from 700 D to 1800 D, from 700 D to 1700 D, from 700 D to 1600 D, from 800 D to 1900 D, from 800 D to 1800 D, from 800 D to 1700 D, from 800 D to 1600 D, from 900 D to 1900 D, from 900 D to 1800 D, from 900 D to 1700 D, from 900 D to 1600 D, from 1000 D to 1900 D, from 1000 D to 1800 D, from 1000 D to 1700 D, from 1000 D to 1600 D, from 1100 D to 1900 D, from 1100 D to 1800 D, from 1100 D to 1700 D, from 1100 D to 1600 D, from 1200 D to 1900 D, from 1200 D to 1800 D, from 1200 D to 1700 D, from 1200 D to 1600 D, or from 1200 D to 1500 D). In case of upper limit, the denier can be less than 2000 D (e.g., less than 2000 D, less than 1900 D, less than 1800 D, less than 1700 D, less than 1600 D, less than 1500 D, less than 1400 D, less than 1300 D, less than 1200 D, less than 1100 D, less than 100 D, less than 900 D, less than 800 D, less than 700 D, less than 600 D, less than 500 D, less than 400 D, less than 300 D, less than 200 D, less than 100 D, less than 50 D, or less than 30 D). In case of lower limit, the denier can be greater than 20 D (e.g., greater than 30 D, greater than 50 D, greater than 100 D, greater than 200 D, greater than 300 D, greater than 400 D, greater than 500 D, greater than 600 D, greater than 700 D, greater than 800 D, greater than 900 D, greater than 1000 D, greater than 1100 D, greater than 1200 D, greater than 1300 D, greater than 1400 D, greater than 1500 D, greater than 1600 D, greater than 1700 D, greater than 1800 D, or greater than 1900 D). In some embodiments, fibers having lower denier (e.g., lower than 20 D) and higher denier (e.g., greater than 2000 D) may be used.

[0080] In some embodiments, the process yield is greater than 70% (e.g., greater than 72%, greater than 75%, greater than 78%, greater than 80%, greater than 83%, greater than 85%, greater than 88%, greater than 90%, greater than 92%, greater than 95%, greater than 98%, or greater than 99%).

[0081] Applicant recognized that reducing the temperature and / or increasing the air flow velocity of quench air in the chimney during a melt spinning process may cool the polyamide fiber below the glass transition temperature as early as possible in the chimney, resulting in significantly higher elongation in the highly amorphous fiber coming into the drawing step. In other words, optimizing the quench air flow velocity and / or temperature is based on the desire to increase the amorphousness of the fiber as it is crystallizing in the chimney. Applicant recognized that the types of copolymersdescribed herein have a lower cry stallization rate, and this lower crystallization rate and the optimized quench air flow rate and / or temperature can work in tandem to create a fiber with higher degree of amorphousness and residual elongation that will be pulled out in the drawing phase of the process. Applicant also recognized certain limitations, such as too high of a quench air flow rate leads to filaments falling out of the thread line. Applicant addressed that in certain embodiments by decreasing the temperature of the quench air flow, which can additionally or alternatively enable early and uniform quenching of the fiber, resulting in an increased degree of amorphousness in the fibers. In some embodiments, the quench air flow velocity may range from 120 feet per minute (ft. / min) to 150 ft. / min. In some embodiments, the temperature of the quench air flow may range from 18 °C and 22 °C.

[0082] Example Performance Characteristics

[0083] As discussed above, tenacity describes the strength of a fiber, fabric, or a yam. Tenacity is defined as the force required to break a fiber, fabric, or a yam, normalized by its linear density. This property gives a measure of the material’s strength relative to its size and is useful when comparing fibers of different types or diameters.

[0084] The tenacity of polyamide materials can be influenced by their crystallization rates. Polyamides can form different stmetures during the crystallization process, which, in turn, affects their mechanical properties, such as tenacity. Crystallization rate can influence tenacity in various ways, such as crystal size and morphology, degree of crystallinity, molecular orientation, internal stresses, internal stresses, and internal defects.

[0085] Molecular orientation-. During production process, the crystallization rate can also affect the degree of molecular orientation in the fiber. Faster cooling or higher take-up speeds can enhance molecular orientation by aligning polymer chains in the direction of the fiber axis. This alignment contributes positively to mechanical properties, including tensile strength.

[0086] Internal stresses and defects: A rapid crystallization rate can introduce internal stresses and defects within the polymer matrix due to uneven shrinkage and less time for molecular rearrangements. These defects might lower the material’s overall tenacity. In contrast, slower crystallization allows for more uniform crystal growth and can potentially reduce internal stresses, leading to fibers with higher tenacity.

[0087] Thermal history and processing conditions: The thermal history and specific processing conditions, such as temperature profiles and cooling rates used during the fiber spinning process, can significantly influence the crystallization kinetics. Optimizing these conditions is important for achieving desired tenacity levels.

[0088] For example, in some embodiments, by incorporating units such as caprolactam (6 monomer units) or sebacic acid (6,10 units), the crystallization rate and spherulite size are ultimately minimized, which enable a reduction in crystallization in a pre-drawing, quench step. Furthermore, increasing the spacing between amide linkages through incorporating long chain units, such as sebacic acid (6,10 units), reduces overall intermolecular forces between chains, which may also lead to improved draw ratios and tenacity improvement. For example, in some embodiments, tenacity increases from 15% to 30% were demonstrated with both PA6,6 / 6 and PA6,6 / 6,10 copolymers, relative to the tenacity of PA6,6 alone.

[0089] Within the melt spinning process utilized for certain embodiments, crystallization rate and intermolecular forces are two variables that can be reduced to increase drawability and tenacity of resulting fibers. Crystallinity and intermolecular interactions in a pre-drawing step limit potential draw ability and chain alignment in the drawing step. Increasing chain alignment can induce taut-tic molecules, which essentially describes strong alignment in amorphous chains that connect crystalline regions. Tenacities achieved on a commercial scale may be much lower than the theoretical highest possible tenacity for a given polymer system. For example, commercially achieved tenacities fall vastly short of theoretical maximums, with most melt spun polyamide fibers only achieving from 2% to 4% of the theoretical maximum tenacity. As such, the approximately 15% to 30% increase in tenacity enabled by certain embodiments (relative to the tenacity of PA6,6 alone) represents a substantial and important improvement.

[0090] In some embodiments, the fibers made from the polyamide compositions described herein demonstrate a tenacity from 3 to 20 grams per denier (e.g., from 3 to 15 grams per denier, from 4 to 15 grams per denier, from 5 to 15 grams per denier, from 6 to 15 grams per denier, from 7 to 15 grams per denier, or from 8 to 15 grams per denier). In terms of lower limit, the polyamide composition can demonstrate a tenacity greater than 3 grams per denier (e.g., greater than 4 grams per denier, greater than 5 grams per denier, greater than 6 gram per denier, greater than 8 grams per denier, greater than 8.5 grams per denier, greater than 8.8 grams per denier, greater than 9 grams per denier, greater than 10 grams per denier, greater than 11 grams per denier, greater than 12 grams per denier, greater than 14 grams per denier, greater than 15 grams per denier, or greater than 20 grams per denier). Tenacity can be measured via ASTM D3822 (2018).

[0091] FIG. 1 is a graphical representation indicating tenacity (grams of force per denier) as a function of draw ratio for example polyamide fiber compositions. The following polyamide fiber compositions were analyzed:• a PA66 control fiber containing only PA6,6;• a PA66 / 6 fiber containing 77 wt. % PA6,6 and 23 wt. % PA6;• a PA66 / 610 fiber containing 70 wt. % PA6,6 and 30 wt. % PA6,10;• a PA66 / 610 fiber containing 70 wt. % PA6,6 and 30 wt. % PA6,10; and• a PA66 / 610 fiber containing 58 wt. % PA6,6 and 42 wt. % PA6,10.For the represented example polyamide fibers, a fairly linear trend (R2= 0.8011) is observed in which the tenacity of the polyamide fibers increases with increasing draw ratio. It is noted that a number of the embodiments containing both the amide monomer segments and the polyamide copolymer segments demonstrated higher draw ratios and higher tenacities than could be achieved using the PA66 control fiber containing only amide monomer segments.

[0092] In some embodiments, the polyamide composition demonstrates a time to crystallize being greater than 10 seconds when the temperature is from 100 °C to 220 °C (e.g., greater than 15 seconds, greater than 20 seconds, greater than 25 seconds, greater than 30 seconds, greater than 35 seconds, greater than 40 seconds, greater than 45 seconds, greater than 50 seconds, greater than 55 seconds, greater than 60 seconds, greater than 65 seconds, greater than 70 seconds, greater than 75 seconds, greater than 80 seconds, greater than 85 seconds, greater than 90 seconds, greater than 95 seconds, or greater than 100). In comparison, neat PA6,6 fully crystallizes in less than 10 seconds under the same temperature.

[0093] The melting point (Tm) of a polymeric material is the temperature at which the material undergoes a phase transition from crystallinity. Melting temperatures can be measured with, for example, the standard test method ISO 11357-3 (2018). In some embodiments, the polyamide composition exhibits a Tmranging from 150 °C to 310 °C (e.g., 150 °C to 300 °C, 150 °C to 290 °C, 150 °C to 280 °C, 150 °C to 270 °C, 150 °C to 260 °C, from 155 °C to 253 °C, from 165 °C to 261 °C, from 175 °C to 269 °C, from 185 °C to 277 °C, or from 195 °C to 285 °C). In terms of upper limits, the Tmcan be less than 310 °C (e.g., less than 300 °C, less than 290 °C, less than 280 °C, less than 277 °C, less than 269 °C, less than 261 °C, less than 253 °C, less than 245 °C, less than 237 °C, less than 229 °C, less than 221 °C, or less than 213 °C. In terms of lower limits, the Tmcan be greater than 150 °C (e.g., greater than 155 °C, greater than 160 °C, greater than 165 °C, greater than 170 °C, greater than 175 °C, greater than 180 °C, greater than 185 °C, greater than 190 °C, greater than 195 °C, greater than 200 °C, greater than 210 °C, greater than 221 °C, greater than 229 °C, greater than 237 °C, greater than 245 °C, greater than 253 °C, greater than 261 °C, greater than 269 °C, greater than 277 °C, greater than 280 °C, greater than 290 °C, or greater than 300 °C). In some embodiments,higher temperatures (e.g., greater than 310 °C) and lower temperatures (e.g., less than 150 °C) may alternatively be used.

[0094] It can be beneficial for polyamide compositions to have high tensile strengths, for example, because of the accompanying resistance of products manufactured from these compositions from failure resulting from tensile forces. Tensile strengths can be measured with, for example, the standard test method ASTM D3822 (2018) or ISO 527-2 (2012).

[0095] In some embodiments, the fibers made from the polyamide composition demonstrate a tensile strength ranging from 150 megapascals (MPa) to 255 MPa (e.g., from 150 MPa to 213 MPa, from 160.5 MPa to 223.5 MPa, from 171 MPa to 234 MPa, from 181.5 MPa to 244.5 MPa, or from 192 MPa to 255 MPa). The tensile strength of the composition can range from 185 MPa to 205 MPa (e.g., from 185 MPa to 197 MPa, from 187 MPa to 199 MPa, from 189 MPa to 201 MPa, from 191 MPa to 203 MPa, or from 193 MPa to 205 MPa). In terms of upper limits, the tensile strength can be less than 255 MPa (e.g., less than 244.5 MPa, less than 234 MPa, less than 223.5 MPa, less than 213 MPa, less than 205 MPa, less than 203 MPa, less than 201 MPa, less than 199 MPa, less than 197 MPa, less than 195 MPa, less than 193 MPa, less than 191 MPa, less than 189 MPa, less than 187 MPa, less than 185 MPa, less than 181.5 MPa, less than 171 MPa, or less than 160.5 MPa). In terms of lower limits, the tensile strength can be greater than 150 MPa (e.g., greater than 160.5 MPa, greater than 171 MPa, greater than 181.5 MPa, greater than 185 MPa, greater than 187 MPa, greater than 189 MPa, greater than 191 MPa, greater than 193 MPa, greater than 195 MPa, greater than 197 MPa, greater than 199 MPa, greater than 201 MPa, greater than 203 MPa, greater than 205 MPa, greater than 213 MPa, greater than 223.5 MPa, greater than 234 MPa, or greater than 244.5 MPa). In some embodiments, higher tensile strengths (e.g., greater than 255 MPa) and lower strengths (e.g., less than 150 MPa) may alternatively be obtained.

[0096] The strength of the fibers made from the polyamide composition can also be characterized in terms of its elongation properties. It can be beneficial for polymeric materials to have high elongation because products manufactured from these materials are often subjected to stretching forces that can cause a material with low elongation to tear or rupture. Elongation can be measured with, for example, the standard test method ASTM D3822 (2018).

[0097] In some embodiments, the fibers made from the polyamide composition demonstrate an elongation at break ranging from 10% to 50% (e.g., from 10% to 45%, from 15% to 40%, from 15% to 38%, from 15% to 35%, or from 18% to 30%, or from 20% to 30%. In terms of upper limits, the elongation can be less than 50% (e.g., less than 45%, less than 40%, less than 35%, less than 30%, less than 25%, less than 20%, less than 15%, or less than 11%). In terms of lower limits, the elongationcan be greater than 10% (e.g., greater than 15%, greater than 20%, greater than 25%, greater than 30%, greater than 35%, greater than 40%, greater than 45 %, or greater than 49%). In some embodiments, higher elongations (e.g., greater than 50%) and lower elongations (e.g., less than 10%) may alternatively be obtained.

[0098] FIG. 2 is a graphical representation indicating tenacity (grams of force per denier) and elongation at break (%) as a function of draw ratio for three example polyamide fiber compositions. The points labeled as “PA66” represent a polyamide fiber containing only PA6,6 as a comparative example, while the points labeled “66 / 610 (80 / 20)” correspond to an example embodiment of a polyamide fiber containing 80 wt.% PA6,6 and 20% PA6,10, and the points labeled “66 / 610 (70 / 30)” correspond to an example embodiment of a polyamide fiber containing 70 wt.% PA6,6 and 30 wt.% PA6,10. For the PA6,6 comparative example, a draw ratio of 4.6 is typically used in order to obtain an elongation at break of approximately 20%, which results in a tenacity of approximately 8.6 grams per denier. In contrast, for the embodiments of the PA6,6 / 6,10 polyamide fibers, draw ratios greater than or equal to 5.6 resulted in elongation at break values greater than or equal to 18% and tenacity values greater than or equal to 9.5 grams per denier. Indeed, some embodiments of the PA6,6 / 6,10 polyamide fibers enabled draw ratios of 5.8 or more, which resulted in elongation at break values greater than or equal to 20% and tenacity values greater than or equal to 10 grams per denier.

[0099] As used herein, “greater than” and “less than” limits may also include the number associated therewith. Stated another way, “greater than” and “less than” may be interpreted as “greater than or equal to” and “less than or equal to.” It is contemplated that this language may be subsequently modified in the claims to include “or equal to.” For example, “greater than 4.0” may be interpreted as, and subsequently modified in the claims as “greater than or equal to 4.0.”

[0100] In some embodiments, any or some of the components or steps disclosed herein may be considered optional. In some embodiments, the disclosed compositions may expressly exclude any or some of the aforementioned components or steps in this description, e.g., via claim language. For example, claim language may be modified to recite that the disclosed compositions, materials processes, and so forth, do not utilize or contain one or more of the aforementioned components, for example, the claim language may be modified to recite that the disclosed materials do not comprise long chain polyamide component (e.g., PA6,T). Such negative limitations are contemplated, and this text serves as support for negative limitations for components, steps, and / or features.Examples

[0101] The present disclosure will be better understood in view of the following non-limiting examples. The following examples are intended for illustrative purposes only and do not limit in any way the scope of the present disclosure.

[0102] In a first example, the polyamide compositions of comparative example A (Comp. Ex. A) and inventive examples 1, 2, and 3 were prepared using the materials and amounts as shown in Table 1. Unless otherwise indicated, the values are in weight percentages based on the total number segments of the polyamide composition. Comparative example A contained only PA6,6 polymer with amide monomer segments. The polyamide compositions of examples 1-3 contained from 70 wt. % to 80 wt. % of PA6,6 amide monomer segments. The compositions of example 1-3 additionally contained from 20 wt. % to 30 wt. % of a different type of polyamide copolymer segment (e.g., PA6 or PA6,10). The compositions were made into fibers. Advantageously, examples 1-3 were able to utilize a final draw ratio of around 6, while comparative example A required a lower final draw ratio of 4.6. The use of the higher draw ratio contributed to unexpected improvements in performance characteristics, including increased tenacity. The fibers of comparative example A and examples 1-3 all had a denier from approximately 420D to approximately 440 D. As indicated in Table 1, examples 1-3 demonstrate a higher tenacity (e.g., from approximately 24% to approximately 28% higher tenacity) relative to comparative example A. In light of these results, Applicant recognized that embodiments containing PA6,6 / 6,10 (e.g., Examples 2 and 3) provide an excellent overall market solution based on, for example, (i) achievable tenacity, (ii) cleanliness, (iii) higher melting point, (iv) the sustainability of sebacic acid, (v) the solid state polymerization robustness. Furthermore, Applicant further recognized that embodiments containing PA6,6 / 6,10 (e.g., Examples 2 and 3) offer a well-rounded solution, at least in terms of tenacity, elongation, shrinkage, and melting point.

[0103] Table 1. Materials and results for first example.

[0104] As Table 1 shows, the use of the polyamide copolymer segments along with the higher percentage of amide monomer segments provides for a surprising increase in fiber tenacity, including an increase of about 25% or more compared to comparative example A. The incorporation of the polyamide copolymer segments (PA6 or PA6,10) to the amide monomer segment (PA6,6) advantageously lowers the melting point of the polyamide compositions, without compromising the elongation at break of the fibers, or negatively impacting the thermal properties of the fibers.

[0105] hr a second example, the polyamide compositions of comparative example A (Comp. Ex. A) and inventive examples 4, 5, 6, 7 and 8 were prepared using the materials and amounts as shown in Table 2. Unless otherwise indicated, the values are in weight percentages based on the total number segments of the polyamide composition. As noted, comparative example A contained only PA6,6 amide monomer segments. The polyamide compositions of examples 4-8 contained approximately 70 wt. % to 90 wt. % of PA6,6 amide monomer segments. The compositions of examples 4-8 additionally contained a different type of polyamide copolymer segment (e.g., PA6,T, PA6, or PA6,10). The compositions were made into fibers. The fibers of comparative example A and examples 4-8 all had a denier around 420 D. Example 5 consistently produced excellent results, achieving a tenacity greater than 11 grams / denier while still maintaining an elongation at break of approximately 20%.

[0106] Table 2: Materials and results for second example.

[0107] In a third example, the polyamide compositions of comparative example B (Comp. Ex. B) and inventive example 9 were prepared using the materials and amounts as shown in Table 3. Unless otherwise indicated, the values are in weight percentages based on the total number segments of thepolyamide composition. As noted, comparative example B contained only PA6,6 amide monomer segments. The polyamide compositions of example 9 contained approximately 80 wt. % of PA6,6 amide monomer segments and approximately 20 wt. % of a polyamide copolymer segment (PA6,10). The compositions were made into fibers. The fibers of comparative example B and example 9 had a denier around 1260 D. Example 9 was able to achieve an approximately 23% increase in draw ratio, an approximately 15% increase in fiber tenacity, an approximately 15% increase in fiber break strength, and an approximately 4% increase in fiber elongation, relative to comparative example B . Example 9 consistently produced excellent results, achieving a tenacity greater than 11 grams per denier while still maintaining an elongation at break of approximately 20%.

[0108] Table 3: Materials and results for third example.

[0109] The above examples demonstrate that the synergistic combination of polyamide copolymer segments and amide monomer segments beneficially provide for improved and / or enhanced properties of the overall composition (e.g., maintaining good elongation properties, higher tenacity, and better draw ratio).

[0110] Embodiments

[0111] The following embodiments are contemplated. All combinations of features and embodiments are contemplated.

[0112] Embodiment 1: A polyamide fiber comprising: a polyamide composition including: at least 55 weight percent (wt. %) amide monomer segments, based on a total number of segments in the polyamide composition; and polyamide copolymer segments; wherein the polyamide fiber has a tenacity greater than 3 grams per denier, as determined in accordance with ASTM D3822 (2018).

[0113] Embodiment 2: The polyamide fiber of Embodiment 1, wherein the polyamide composition comprises from 1 peq / g to 80 peq / g capped end groups, and wherein the capped end groups comprise a capping agent comprising acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid, octanoic acid, palmitic acid, myristic acid, decanoic acid, undecanoic acid, dodecanoic acid, oleic acid, or stearic acid, or any combinations thereof.

[0114] Embodiment 3: The polyamide fiber of any of Embodiments 1-2, wherein the polyamide composition comprises from 10 wt. % to 45 wt. % of the polyamide copolymer segments, based on the total number of segments in the polyamide composition, and wherein the polyamide copolymer segments comprise PA6; PA6,10; PA6,12; or PA6,T; or combinations thereof.

[0115] Embodiment 4: The polyamide fiber of any of Embodiments 1-3, wherein the polyamide composition comprises at least 70 wt. % amide monomer segments and from 10 wt. % to 30 wt. % of the polyamide copolymer segments, based on the total number of segments in the polyamide composition, wherein the amide monomer segments comprise PA6,6; and wherein the polyamide copolymer segments comprise PA6; PA6,10; PA6,12; or PA6,T; or combinations thereof.

[0116] Embodiment 5: The polyamide fiber of any of Embodiments 1-4, wherein a draw ratio of the polyamide fiber is greater than 5, and the tenacity of the polyamide fiber is greater than 9 grams per denier, as determined in accordance with ASTM D3822 (2018).

[0117] Embodiment 6: The polyamide fiber of any of Embodiments 1-5, wherein the draw ratio of the polyamide fiber is at least 5.6, and the tenacity of the polyamide fiber is at least 10 grams per denier, as determined in accordance with ASTM D3822 (2018).

[0118] Embodiment 7: The polyamide fiber of any of Embodiments 1-6, wherein the polyamide composition demonstrates a time to fully crystallize greater than 10 seconds at a temperature ranging from 100 °C to 220 °C.

[0119] Embodiment 8: The polyamide fiber of any of Embodiments 1-7, wherein the polyamide composition comprises less than 15 wt. % non-linear monomer segments, based on the total number of segments in the polyamide composition.

[0120] Embodiment 9: The polyamide fiber of any of Embodiments 1-8, wherein the polyamide composition does not comprise isophthalic acid, meta-xylene diamine, or 2-methyl pentamethylene diamine segments.

[0121] Embodiment 10: The polyamide fiber of any of Embodiments 1-9, wherein the polyamide fiber has a linear mass density ranging from 20 denier (D) to 2000 D.

[0122] Embodiment 11 : The polyamide fiber of any of Embodiments 1-10, wherein the polyamide fiber has an elongation at break of at least 18%, as determined in accordance with ASTM D3822 (2018).

[0123] Embodiment 12: A method for making a polyamide fiber, the method comprising: preparing a polyamide composition comprising: at least 55 weight percent (wt. %) amide monomer segments, based on a total number of segments in the polyamide composition; and polyamide copolymer segments; and melt spinning the polyamide composition, thereby to yield the polyamidefiber having a tenacity greater than 3 grams per denier, as determined in accordance with ASTM D3822 (2018).

[0124] Embodiment 13: The process of Embodiment 12, wherein the preparing of the polyamide composition comprises capping an amine end group of the polyamide composition with a capping agent.

[0125] Embodiment 14: The process of Embodiment 13, wherein the capping agent comprises acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid, octanoic acid, palmitic acid, myristic acid, decanoic acid, undecanoic acid, dodecanoic acid, oleic acid, or stearic acid, or any combinations thereof.

[0126] Embodiment 15: The process of Embodiments 12-14, wherein the polyamide fiber has an elongation at break of at least 18%, as determined in accordance with ASTM D3822 (2018).

[0127] Embodiment 16: The process of Embodiments 12-15, wherein a process yield of the polyamide fiber is greater than 70%.

[0128] Embodiment 17: The process of Embodiments 12-16, wherein the polyamide composition comprises from 10 wt. % to 45 wt. % of the polyamide copolymer segments, based on the total number of segments in the polyamide composition.

[0129] Embodiment 18: The process of Embodiments 12-17, wherein the melt spinning of the polyamide composition comprises drawing the polyamide composition using a draw ratio greater than 5, and wherein the tenacity of the polyamide fiber is greater than 9 grams per denier, as determined in accordance with ASTM D3822 (2018).Embodiment 19: The process of Embodiment 18, wherein the draw ratio is at least 5.6, and wherein the tenacity of the polyamide fiber is at least 10 grams per denier, as determined in accordance with ASTM D3822 (2018).

[0130] Embodiment 20: The process of Embodiments 12-19, wherein the polyamide fiber demonstrates a time to fully crystallize greater than 10 seconds at a temperature ranging from 100 °C to 220 °C.

[0131] When ranges are disclosed herein, ranges from any lower limit may be combined with any upper limit to recite a range not explicitly recited, as well as, ranges from any lower limit may be combined with any other lower limit to recite a range not explicitly recited, in the same way, ranges from any upper limit may be combined with any other upper limit to recite a range not explicitly recited. Additionally, reference to values stated in ranges includes each and every value within that range, even though not explicitly recited. Thus, every point or individual value may serve as its ownlower or upper limit combined with any other point or individual value or any other lower or upper limit, to recite a range not explicitly recited.

[0132] Other objects, features and advantages of the disclosure will become apparent from the foregoing drawings, detailed description, and examples. These drawings, detailed description, and examples, while indicating specific embodiments of the disclosure, are given by way of illustration only and are not meant to be limiting. In further embodiments, features from specific embodiments may be combined with features from other embodiments. For example, features from one embodiment may be combined with features from any of the other embodiments. In further embodiments, additional features may be added to the specific embodiments described herein. It should be understood that although the disclosure contains certain aspects, embodiments, and optional features, modification, improvement, or variation of such aspects, embodiments, and optional features can be resorted to by those skilled in the art, and that such modification, improvement, or variation is considered to be within the scope of this disclosure.

Claims

We claim:

1. A polyamide fiber comprising: a polyamide composition including: at least 55 weight percent (wt. %) amide monomer segments, based on a total number of segments in the polyamide composition; and polyamide copolymer segments; wherein the polyamide fiber has a tenacity greater than 3 grams per denier, as determined in accordance with ASTM D3822 (2018).

2. The polyamide fiber of claim 1, wherein the polyamide composition comprises from 1 microequivalents per gram (peq / g) to 80 ucq / g capped end groups, wherein the capped end groups comprise a capping agent comprising acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid, octanoic acid, palmitic acid, myristic acid, decanoic acid, undecanoic acid, dodecanoic acid, oleic acid, or stearic acid, or any combinations thereof.

3. The polyamide fiber of claim 1, wherein the polyamide composition comprises from 10 wt. % to 45 wt. % of the polyamide copolymer segments, based on the total number of segments in the polyamide composition, and wherein the polyamide copolymer segments comprise PA6; PA6,10; PA6,12; or PA6,T; or combinations thereof.

4. The polyamide fiber of claim 1, wherein the polyamide composition comprises at least 70 wt. % amide monomer segments and from 10 wt. % to 30 wt. % of the polyamide copolymer segments, based on the total number of segments in the polyamide composition, wherein the amide monomer segments comprise PA6,6; and wherein the polyamide copolymer segments comprise PA6; PA6,10; PA6,12; or PA6,T; or combinations thereof.

5. The polyamide fiber of claim 1, wherein a draw ratio of the polyamide fiber is greater than 5, and the tenacity of the polyamide fiber is greater than 9 grams per denier, as determined in accordance with ASTM D3822 (2018).

6. The polyamide fiber of claim 5, wherein the draw ratio of the polyamide fiber is at least 5.6, and the tenacity of the polyamide fiber is at least 10 grams per denier, as determined in accordance with ASTM D3822 (2018).

7. The polyamide fiber of claim 1 , wherein the polyamide composition demonstrates a time to fully crystallize greater than 10 seconds at a temperature ranging from 100 °C to 220 °C.

8. The polyamide fiber of claim 1, wherein the polyamide composition comprises less than 15 wt. % non-linear monomer segments, based on the total number of segments in the polyamide composition.

9. The polyamide fiber of claim 1, wherein the polyamide composition does not comprise isophthalic acid, meta-xylene diamine, or 2-methyl pentamethylene diamine segments.

10. The polyamide fiber of claim 1, wherein the polyamide fiber has a linear mass density ranging from 20 denier (D) to 2000 D.

11. The polyamide fiber of claim 1, wherein the polyamide fiber has an elongation at break of at least 18%, as determined in accordance with ASTM D3822 (2018).

12. A method for making a polyamide fiber, the method comprising: preparing a polyamide composition comprising: at least 55 weight percent (wt. %) amide monomer segments, based on a total number of segments in the polyamide composition; and polyamide copolymer segments; and melt spinning the polyamide composition, thereby to yield the polyamide fiber having a tenacity greater than 3 grams per denier, as determined in accordance with ASTM D3822 (2018).

13. The method of claim 12, wherein the preparing of the polyamide composition comprises capping an amine end group of the polyamide composition with a capping agent.

14. The method of claim 13, wherein the capping agent comprises acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid, octanoic acid, palmitic acid, myristic acid, decanoic acid, undecanoic acid, dodecanoic acid, oleic acid, or stearic acid, or any combinations thereof.

15. The method of claim 12, wherein the polyamide fiber has an elongation at break of at least 18%, as determined in accordance with ASTM D3822 (2018).

16. The method of claim 12, wherein a process yield of the polyamide fiber is greater than 70%.

17. The method of claim 12, wherein the polyamide composition comprises from 10 wt. % to 45 wt. % of the polyamide copolymer segments, based on the total number of segments in the polyamide composition.

18. The method of claim 12, wherein the melt spinning of the polyamide composition comprises drawing the polyamide composition using a draw ratio greater than 5, and wherein the tenacity of the polyamide fiber is greater than 9 grams per denier, as determined in accordance with ASTM D3822 (2018).

19. The method of claim 18, wherein the draw ratio is at least 5.6, and wherein the tenacity of the polyamide fiber is at least 10 grams per denier, as determined in accordance with ASTM D3822 (2018).

20. The method of claim 12, wherein the polyamide fiber demonstrates a time to fully crystallize greater than 10 seconds at a temperature ranging from 100 °C to 220 °C.

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