CA3148189C - Biodegradable synthetic polymer fibre - Google Patents

Abstract

There is provided a synthetic polymer fibre having an amorphous phase of at least 10 % of the crystallinity ratio. The synthetic polymer fibre includes 0.1 to 5.0 wt. % of a biodegradation-inducing additive with respect to the total weight of the synthetic polymer fibre. The biodegradation-inducing additive is incorporated in the amorphous phase such that the biodegradation-inducing additive is physically and/or chemically accessible for a biodegradation initiation to form nuclei of biodegradation within the amorphous phase.

Description

BIODEGRADABLE SYNTHETIC POLYMER FIBRE
CROSS-REFERENCE TO A RELATED APPLICATION
[0001] The present application claims priority from U. S. provisional patent application serial number 63/146005 filed on February 5, 2021.
TECHNICAL FIELD

[0002] The present disclosure generally relates to the field of biodegradable textiles, yarns, fibers and methods for making same.
BACKGROUND

[0003] One commonly used material in textile items is a synthetic polymer such as polyester and nylon. The textile industry has produced and is producing an alarming amount of synthetic polymers, such as polyester textile, that is not biodegradable. The degradation of synthetic textile (polyesters, nylon, and the like) in landfills or oceans can take up to a hundred years or more. Furthermore, washing polyester containing clothes in washing machines releases micro-fibers into the water ecosystem. The micro-plastics pollute the oceans and can make their way up the food chain to fish that are consumed by the human population. There is therefore a need for improving the biodegradability and sustainability of synthetic textiles such as polyester and nylon.
SUMMARY

[0004] In one aspect, there is provided a synthetic polymer fibre including: an amorphous phase of at least 10 % of the crystallinity ratio, and 0.1 to 5.0 wt. % of a biodegradation-inducing additive with respect to the total weight of the synthetic polymer fibre, the biodegradation-inducing additive being incorporated in the amorphous phase such that the biodegradation-inducing additive is physically and/or chemically accessible for a biodegradation initiation to form nuclei of biodegradation within the amorphous phase.

[0005] In one embodiment, the synthetic polymer fibre is a polyester fibre or a polyamide fibre.

Date Recue/Date Received 2023-04-03

[0006] In one embodiment, the biodegradation-inducing additive is dispersed in the amorphous phase.

[0007] In one embodiment, the synthetic polymer fiber is made of a polymer is selected from poly(butylene succinate) (PBS), poly(butylene succinate)-co-(butylene adipate) (PBSA), poly(c-caprolactone) (PCL), poly(ethylene succinate) (PES), poly(1-lactic acid) (PLA), poly(3-hydroxybutyrate) and poly(3-hydoxybutyrate-co-3-hydroxyvalterate) (PHB/PHBV), poly(ethylene terephthalate) (PET), poly(butylene terephthalate) (PBT), poly(butylene adipate-co-terephthalate (PBAT), poly(butylene succinate-co-terephthalate) (PBST), poly(butylene succinate/terephthalate/isophthalate)-co-(lactate) (PBSTIL), and combinations thereof.

[0008] In one embodiment, the biodegradation-inducing additive is selected from polysaccharide, polylactic acid, polycaprolactone, polybutylene succinate, polybutylene terephthalate-coadipate, furanone, glutaric acids, carboxylic acids, or EcoPureTM G2 additive.

[0009] In one embodiment, the biodegradation-inducing additive is a starch-based polymer.

[0010] In one embodiment, the biodegradation-inducing additive is present in a concentration of between 0.5 to 3.0 wt % with respect to the total weight of the synthetic polymer fibre.

[0011] In one embodiment, the synthetic polymer fibre further comprises a carrier polymer.

[0012] In one embodiment, the carrier polymer is selected from wool, flax, cotton, hemp, linen, cellulose, rayon, nylon, and/or silk.

[0013] In one embodiment, a weight ratio of the synthetic polymer fibre to the carrier polymer is between 1:10 to 10:1.

[0014] In one embodiment, the synthetic polymer fibre further includes a flame retardant additive.

Date Recue/Date Received 2022-02-07

[0015] In one embodiment, the biodegradation-inducing additive is incorporated in the amorphous phase by physisorption, absorption or adsorption and does not form any intramolecular chemical bonds with the synthetic polymer fibre.

[0016] In one aspect, there is provided a system for detecting the presence of a biodegradable-inducing additive in a synthetic polymer fibre, the system including: the synthetic polymer fibre of the present disclosure; and a colorimetric agent for changing a color of the synthetic polymer fibre, where a color change within a given spectrum range, indicates the presence or absence of the biodegradation-inducing additive in the synthetic polymer fibre.

[0017] In a further aspect there is provided a method of fabricating a biodegradable synthetic fibre, including: obtaining the biodegradable synthetic fibre having an extruded synthetic polymer body; swelling the extruded synthetic polymer body to obtain a swelled extruded synthetic polymer body having an increased surface porosity when compared to the extruded synthetic polymer body; and incorporating a biodegradation-inducing additive into the swelled extruded synthetic polymer body, wherein the biodegradation-inducing additive penetrates pores of the surface of the swelled extruded synthetic polymer body.

[0018] In one embodiment, incorporating the biodegradation-inducing additive is performed in one of a jet dyeing step, a beam dyeing step, a pad application step, or an autoclave purification step.

[0019] In one embodiment, incorporating the biodegradation-inducing additive into the swelled extruded synthetic polymer body includes embedding the biodegradation-inducing additive in an amorphous phase of the swelled extruded synthetic polymer body.

[0020] In one embodiment, incorporating the biodegradation-inducing additive includes increasing a temperature of the extruded polyester body to a temperature of from 100 to 150 C.

[0021] In one embodiment, the biodegradable synthetic polymer is a biodegradable polyester.

[0022] In yet a further aspect, there is provided a method of detecting whether a biodegradation-inducing additive is present in a amorphous phase of a synthetic polymer fibre, the method includes: contacting a colorimetric agent with the synthetic polymer fibre;

Date Recue/Date Received 2022-02-07 and observing a change of color in the synthetic polymer fibre, a color change within a given spectrum range indicating the presence or absence of the biodegradation-inducing additive in the amorphous phase.

[0023] In still a further aspect, there is provided a method of detecting whether a biodegradation-inducing additive is present in a amorphous phase of a synthetic polymer fibre, the method includes: contacting a colorimetric agent with the synthetic polymer fibre;
heating the synthetic polymer fibre to a temperature of 100-150 C in an aqueous phase;
observing a change of color in the aqueous phase, a color change within a given spectrum range indicating the presence or absence of the biodegradation-inducing additive in the amorphous phase.

[0024] Many further features and combinations thereof concerning the present improvements will appear to those skilled in the art following a reading of the instant disclosure.
DESCRIPTION OF THE DRAWINGS

[0025] Fig. 1 is a flow chart illustrating a method for fabricating a biodegradable polyester in accordance with the present disclosure.

[0026] Fig. 2 is a graph showing the biodegradation (in percentage) in function of time (days) of two controls (negative and positive) and two textile samples in accordance with the present disclosure.

[0027] Fig. 3 is a graph showing the biodegradation (in percentage) in function of time (days) of two textile samples in accordance with the present disclosure compared with a negative control.

[0028] Fig. 4 is a photograph showing textile fibers stained with a colorimetric indicator for determining the presence of the biodegradation-inducing additive.
DETAILED DESCRIPTION

[0029] The present disclosure concerns biodegradable synthetic polymers, and particularly polyesters and nylons suitable for the textile industry. A
synthetic polymer is a man made polymer. Herein below, the present disclosure describes polyesters in relation to a method of manufacturing a biodegradable synthetic fiber. However, the polyester can Date Recue/Date Received 2022-02-07 be replaced by any other synthetic polymer, for example nylon (Le. a polyamide). For simplicity, the present disclosure focuses primarily on polyester fibers, though it extends to other synthetic fibers.

[0030] The synthetic polymers of the present disclosure, such as polyester, have an amorphous phase in their crystalline structure. In some embodiments, the synthetic polymers are semi-crystalline and have an amorphous phase of at least 10 %, 15 %, 20 %, 25 %, or 30% of the crystalline ratio. In one example, the synthetic polymer is polyester as described below. The polyester can have an amorphous phase of at least 10 %, 15 %, 20 %, 25 %, or 30 % of the crystallinity ratio. The amorphous phase percentage can vary based on whether the polyester is a recycled polyester. Recycled polyester can have an amorphous phase of at least 35 % or at least 40 %.

[0031] A polyester is a polymer containing repeating ester moieties separated by monomers such as a hydrocarbon chain that is optionally branched, optionally interrupted, optionally substituted, saturated or unsaturated. The polyester can have a molecular weight of 10,000 Da, 15,000 Da or more. The biodegradable polyester can be an aliphatic polyester or an aromatic polyester. In some embodiments, aliphatic polyesters may have a better biodegradability than aromatic polyesters. Aliphatic polyesters generally have more hydrolysable ester bonds that are susceptible to hydrolysis (for example with enzymes such as depolymerases). In addition, aliphatic polyesters generally have a more flexible polymeric chain which facilitates degradation. However, biodegradable polyesters can also be an aliphatic-aromatic co-polyester. In one embodiment, the polyester is selected from poly(butylene succinate) (PBS), poly(butylene succinate)-co-(butylene adipate) (PBSA), poly(c-caprolactone) (PCL), poly(ethylene succinate) (PES), poly(1-lactic acid) (PLA), poly(3-hydroxybutyrate) and poly(3-hydoxybutyrate-co-3-hydroxyvalterate) (PHB/PHBV), poly(ethylene terephthalate) (PET), poly(butylene terephthalate) (PBT), poly(butylene adipate-co-terephthalate (PBAT), poly(butylene succinate-co-terephthalate) (PBST), poly(butylene succinatetterephthalate/isophthalate)-co-(lactate) (PBSTIL), and combinations thereof.

[0032] A textile according to the present disclosure is a type of material composed of a synthetic polymer such as polyester, that may be in the form of fibers, filaments, yarns, membranes or fabrics. The fibers, filaments, yarns, and fabrics may be in knit, woven or non-woven forms. The term "non-woven" may be defined as a textile structure that was Date Recue/Date Received 2022-02-07 manufactured using mechanical, chemical, thermal, solvent methods, or combinations thereof to bond and/or interlock fibers. Many natural or synthetic fibers can be manufactured into yarns and threads, these include for example wool, flax, cotton, hemp, linen, nylon, silk, and polyester. Cotton and polyester are among the most common fibers in the textile industry that are used to produce yarns. In some embodiments, the textile material of the present disclosure, with polyester, can include at least a portion of recycled natural and/or synthetic fibers, filaments, yarns, fabrics, and precursor forms.

[0033] The term "polyester textile" as used herein refers to a textile having at least about 10 wt % of a polyester. In one embodiment, the polyester textile has at least 15 wt %, at least about 20 wt %, at least about 25 wt %, or at least about 30 wt %
of a polyester.
The polyester textile can optionally comprise a polyester in combination with one or more carrier polymers, such as a resin(s). The term "carrier polymer" as used herein refers to polymers that can be combined with polyester into the polyester textile. For a successful production of a textile material the carrier polymer should be compatible and miscible with the polyester. The carrier polymer and the quantity of that carrier polymer can be selected to improve a physical and/or chemical property of the polyester textile. In one embodiment, the carrier polymer can be a nylon, an olefin, a natural polymer, a biodegradable polymer, and/or a thermoplastic biodegradable polymer. For example the carrier polymer can be wool, flax, cotton, hemp, linen, cellulose, rayon, nylon, and/or silk. In one embodiment, the weight percent ratio between the polyester and the carrier polymer in the textile material is between about 1:10 to about 10:1, between about 1:5 to about 5:1, between about 3:1 to about 3:1, between about 2:1 to between about 1:2, or is about 1:1.

[0034] Polyesters have desirable properties for the textile industry. For example, they may exhibit a resistance to certain weak acids and alkalies, to organic solvents (which are often used in cleaning and stain removal products), to bleach damage, to sunlight, to synthetic detergents, and other laundry aids. On the other hand, polyester (untreated and without additives) is not sustainable and lacks biodegradability. Combining polyester with one or more carrier polymers can further improve the properties of the material and/or limit the disadvantages. For example, polyester may commonly be combined with cotton (e.g., at around a 1:1 ratio) to produce a textile for clothing items. A particular application for polyester-cotton blends or polycotton fabrics is for making moisture wicking, wrinkle resistant, tear resistant, soft, and light-weight apparel. Different combinations of polyester and carrier polymers can be used to achieve a specific softness of the textile material, Date Recue/Date Received 2022-02-07 specific moisture-absorbing properties, durability and water resistance. In particular embodiments, the polyester textile can be free of saccharides to improve the durability of the textile. For example, the polyester can have less than 5 wt % of saccharides, less than 3 wt % of saccharides, and less than 1 wt % of saccharides.

[0035] The polyester textile or other like synthetic textile of the present disclosure have a biodegradable additive, a.k.a., a biodegradation-inducing additive incorporated in the amorphous phase to render the polyester (or synthetic textile) biodegradable.
In some embodiments, the biodegradation-inducing additive is dispersed in the amorphous phase of the polymer. The biodegradable additive may be embedded in the amorphous phase of the polyester and dispersed such that many nuclei of biodegradation can occur, thereby improving the rate of biodegradation of the polyester. Thus, for simplicity, the term "biodegradable additive" is used herein and refers to any additive that can render a polyester polymer biodegradable. The biodegradable additive can be a biodegradable polymer. Biodegradable polymers promote the biodegradation of polyester by degrading first thereby creating a porous structure which increases the surface area and reduces the structural stability of polyester thereby further promoting biodegradation.
Examples of biodegradable polymers additives include but are not limited to polysaccharides such as starch-based polymers, polylactic acid, polycaprolactone, polybutylene succinate, polybutylene terephthalate-coadipate, furanone, glutaric acids, carboxylic acids, or EcoPureTM G2 additive. In one embodiment, the biodegradable additive of the present disclosure is a polysaccharide, such as a starch-based polymer.

[0036] The biodegradable additive of the present disclosure is present in the polyester textile (or synthetic textile) between 0.1 to 5.0 wt %, between 0.5 to 3.0 wt %, between 0.5 and 2 wt % or between 1.0 to 2.0 wt % with respect to the total weight of the textile. A
minimal concentration of 0.1 wt %, 0.5 wt % or 1.0 wt % is included to impart on the polyester textile a biodegradability. The concentration of the biodegradable additive is limited to a maximal concentration of 5.0 wt %, 3.0 wt % or 2.0 wt % to maintain the mechanical properties of the polyester textile.

[0037] In one embodiment, the polyester is degraded into small organic molecules by hydrolysis and/or oxidation that are metabolized by microorganisms such as bacteria to turn the polyester into carbon dioxide (CO2), methane (CH4), water (H20), and metabolic biomass. Thus, biodegradation can be mediated by organisms that break down and Date Recue/Date Received 2022-02-07 convert polyester into sustainable products. In biological systems, many factors are at play including but not limited to external mechanical forces, moisture level, humidity, temperature, solar radiation, enzyme activities and other biotic interactions, which can all influence the rate of the microbial biodegradation. More generally, the environmental conditions, which also include a multitude of variable factors, play a major role in determining the rate and efficiency of polyester biodegradation. A second aspect that influences the rate and efficiency of biodegradation is the composition of the polyester textile. For example, a combination of 50/50 polyester and cotton textile is more biodegradable than a majority polyester textile. In the context of the present disclosure, the terms "more biodegradable" or "improved biodegradability" and the like, are comparison terms used when the compositions and environmental conditions of the two textile being compared are similar. Indeed, since cotton degrades much faster than polyester the degradation time of a 50/50 polyester cotton textile cannot be directly compared to a 80/20 polyester cotton. Moreover, two identical textile compositions degrading in environments having different numbers of suitable microorganisms will not degrade at the same rate.

[0038] The term "biodegradable" as used herein with respect to a polyester textile material can be defined as biodegrading at least 90 % of the polyester polymers contained in the polyester textile in less than 4 years. In one embodiment, at least 90 % of the polyester contained in the polyester textile degrades in less than 3 years. In one embodiment, the fibers, yarns, fabrics, and precursors of polyester textile containing the biodegradable additive achieve a biodegradability of at least 8% after 70 days and follows a biodegradation curve to achieve 90 % degradation after 4 years, preferably 3 years according to the ASTM D5511 standard test method for determining anaerobic biodegradation of plastic materials under high-solids anaerobic-digestion conditions.
When studying the biodegradability of a textile, the molecular composition of the precursors, intermediates and final products can be measured using as gel permeation chromatography, or more preferably a gradient analysis of polymer blends. In one example, the biodegradability of the textile polyester is measured, defined, or determined by methods specified in standard test protocols ASTM D6691, ASTM D5210, and ASTM
D5511, developed and published by the American Society for Testing and Materials.
ASTM D6691 is the Standard Test Method for Determining Aerobic Biodegradation of Plastic Materials in the Marine Environment by a Defined Microbial Consortium or Natural Date Recue/Date Received 2022-02-07 Sea Water Inoculum, ASTM D5210 is the Test Method for Determining the Anaerobic Biodegradation of Plastic Materials in the Presence of Municipal Sewage Sludge, and ASTM D5511 is the Standard Test Method for Determining Anaerobic Biodegradation of Plastic Materials Under High-Solids Anaerobic-Digestion Condition. However, ASTM tests are not the only way to define the biodegradability of a textile and other suitable measurements may be used to evaluate the biodegradability of the textiles according to the present disclosure. Other standard tests include but are not limited to those by the Organisation for Economic Co-operations and Development (OECD), or the International Organization for Standardization (ISO).

[0039] To produce the biodegradable polyester textile of the present disclosure the biodegradable additive has to be incorporated in the amorphous phase of the polyester.
In one embodiment, the biodegradable additive is incorporated by absorption, absorption, dispersion and/or physisorption. In one embodiment, the incorporation of the biodegradable additive does not involve any intramolecular chemical bonds between the biodegradable additive and the polyester (e.g. covalent bonds). The incorporation is performed as a post-processing step of polyester textile material formation.
In one embodiment, a "post-processing step" in the context of textile production can be defined herein as a step performed after extrusion of a textile. In one embodiment, a "post-processing" step in the context of textile production may be further defined herein as after the production of a fiber, filament, yarn, membrane and/or fabric from a masterbatch. In one embodiment, the masterbatch is free of biodegradable additives. In one example, the method can specifically exclude any step of adding a biodegradable additive during the masterbatch or extrusion step.

[0040] Referring to Fig. 1, a method for fabricating a biodegradable polyester in accordance with the present disclosure is generally shown at 10. According to 12, a membrane, a strand, a filament, and/or fibers is (are) obtained, with the membrane, strand, filament, and/or fibers having an extruded polyester body. The polyester fiber can be subjected to a melt-spinning and extrusion process where the polyester is heated and becomes a molten polymer. The molten polymer is then extruded through a spinneret in continuous strands or filaments. To produce a mix textile of carrier polymer (for example cotton) and polyester, the extruded product can be blended with polyester and carrier polymer fibers together, and spinning the resulting textile blend. The textile blends of the present disclosure can have properties such as wrinkle, tear, and stain resistance, Date Recue/Date Received 2022-02-07 reduced shrinking, long lasting durability, light weight, and moisture-wicking capabilities.
In one embodiment, more than one carrier polymer can be included to produce the textile material (for example cotton and rayon). Therefore, the resulting textile may be a tri-blend yarn made of polyester, cotton, and rayon. This textile has mechanical properties such as improved softness and moisture-absorbing properties. The present method advantageously allows flexibility in the choice of carrier polymers with polyester and further flexibility in the concentration of those carrier polymers as the biodegradable additive is added after the textile material is formed and therefore does not create any limitations on the composition of the polyester textile blends.

[0041] According to 14, swelling the extruded polyester body to obtain a swelled extruded polyester body having an increased surface porosity when compared to the extruded polyester body. In the context of the present disclosure "swell" or "swelling" is defined as opening or creating porous structures in a polymer textile. The swelling can be induced by increasing the temperature and/or the pressure. The swelling may be performed by heating to a temperature of from 100 to 150 C, from 110 to 145 C, or from 120 to 140 C.

[0042] According to 16, the step of incorporating the biodegradable additive in the polyester is performed while the polyester is swelled. The porous structures, or pores, are exploited to incorporate the biodegradable additives and optionally other components to render the textile biodegradable. Any processing step that swells the polymer can be used as the step to incorporate the biodegradable additive. In one embodiment, the biodegradable additive is incorporated in the polyester during a jet dyeing step, a pad application step, a beam dyeing step or the autoclave purification step. In one embodiment the biodegradable additive is incorporated with the paint, thereby rendering the present highly efficient as most textiles require a painting step anyway.
In some embodiments, the biodegradable additive is incorporated without paint. This can still be done by performing a jet dyeing step, a beam dyeing step or a pad application step while not providing any paint but providing the biodegradable additive. When the polyester is swelled, the increased porosity promotes the incorporation of the biodegradable additive into the polymeric amorphous phase. This can be due to an increase in sites of entry into the polymeric amorphous phase. The biodegradable additive can be provided in solution or in suspension and dispersed into the amorphous phase of the swelled polyester by contacting the suspension or the solution with the swelled polyester.
Date Recue/Date Received 2022-02-07

[0043] The present method of making a textile biodegradable is more cost effective and efficient compared to prior art methods where the biodegradable additives are added at the masterbatch or extrusion step (e.g. when the polymer textile is in the molten state).
Indeed, in one embodiment, the present method achieves a 10 %, preferably 20 %
cost reduction when compared to a prior art method, particularly a prior art method where the biodegradable additive is added before extrusion. If the biodegradable additive is added at the masterbatch or extrusion step according to the prior art, the biodegradable additive may be encapsulated by the polyester. In contrast, the biodegradable additive added during the swelling as described herein incorporates into the amorphous phase of the polyester. Accordingly, a microorganism may not access the biodegradable additive when it is encapsulated in the polyester and may degrade the polyester slower than when the biodegradable additive is accessible to the microorganism and dispersed in the amorphous phase of the polymer.

[0044] As a result from the method 10, there is produced a biodegradable polyester comprising: an extruded polyester body having surface porosity, and a coating(s) on a surface of the extruded polyester body, the coating(s) penetrating pores of the surface, the coating being a biodegradation-inducing additive. The biodegradable polyester may be a membrane, a strand, a filament, fibers, and may be part of a polyester textile.

[0045] There is provided a method of detecting the presence of the biodegradable additive in a polyester textile with a calorimetric agent such as iodine. The detection method is a calorimetric assay in which a change in the color (a.k.a., colour) of the calorimetric agent indicates the presence of the biodegradable additive, such as a change of color within a given spectrum. Conversely, the absence of color change, or a change of color in the wrong spectrum of colors, indicates the absence of the biodegradable additive.
To determine whether the biodegradable additive is incorporated in the amorphous phase of the synthetic polymer (e.g. polyester), a textile, fibers, filaments, yarns, membranes or fabrics, are contacted with the calorimetric agent and the color change of the textile or the like can be observed. In some embodiments, the color can be analyzed by naked eye observation, microscopic observation or by spectrophotometry (with for example a wavelength around 615 nm to identify the presence of blue iodine). In one embodiment, the polyester textile is contacted with the calorimetric agent (such as iodine) and heated in an aqueous phase to a temperature of from 100 to 150 C. The color change or absence of color change can thus be observed in the aqueous phase. If the biodegradable additive Date Recue/Date Received 2022-02-07 was incorporated in the amorphous phase of the polyester it can be released into the aqueous phase and can react with the colorimetric agent to induce the change of color.

[0046] Moreover, the colorimetric assay can help differentiate between a polyester having the biodegradable additive encapsulated therein (prior art) or incorporated in the amorphous phase of the polyester as described above. In one non-limitative example, the biodegradable additive is a polysaccharide such as a starch-based polymer.
Iodine may be provided in solution with potassium (i.e. a solution of potassium iodide).
Other iodine solutions are contemplated by the present disclosure. The potassium iodine solution typically has an orange-brown color. When the iodine comes in contact with the polysaccharide (for example starch), the iodine will change color to become dark blue, for example. When the biodegradable additive is encapsulated in the polyester, the iodine cannot or may have limited access to biodegradable additive. This is also the case even when the polyester is heated to a temperature of from 100 to 150 C and exposed to an aqueous phase containing the colorimetric agent. The colorimetric assay can therefore be used to differentiate between a biodegradable additive that is encapsulated in the polyester versus a biodegradable additive that is incorporated or dispersed in the amorphous phase of the polyester. Indeed, when the biodegradable additive is encapsulated there will be no color change or a very faint color change compared to when the biodegradable additive is dispersed in the amorphous phase of the polyester.

[0047] A further additive may optionally be added to the synthetic polymer, for example an agent that promotes the microbial degradation of polyester (e.g.
recruiting microorganisms or facilitating enzymatic reactions), and/or that promotes the chemical degradation of polyester (e.g. thermal oxidation, photo-oxidation, or hydrolysis). To be absorbed and metabolized by microorganisms the polyester has to be broken down into smaller organic molecules (oligomers, dimers, and/or monomers). In one example, reactions that break down the polyester include hydrolysis and oxidation. The further additive can be provided to promote, facilitate, or enhance microbial degradation which can be by direct or indirect attack on the polyester. In one embodiment, the microbial enzymes involved in polyester biodegradation include but are not limited to lipase, proteinase K, pronase, hydrogenase and the like. In one embodiment, the further additive can be a transition metal, calcium carbonate, a chemo attractant/chemo taxi agent, and/or an acid. The further additive can be a composition of elements that may not impart Date Recue/Date Received 2022-02-07 biodegradability on their own but combine to achieve the effect of promoting biodegradability.

[0048] The biodegradable polyester textile of the present disclosure can be used to produce any type of textile material. For example, the textile material can be used in the manufacture of knit fabrics, woven fabrics, nonwoven fabrics, apparel, upholstery, carpeting, bedding such as sheets or pillowcases, and industrial use fabrics for agriculture or construction. Further examples of apparel include: shirts, pants, bras, panties, hats, undergarments, coats, skirts, dresses, tights, stretch pants, scarves, outerwear, suits, underwear, swimsuits, active-wears, belts, ponchos, trousers, shorts, footwear, fleece, tees, bottoms, socks, bag, handkerchiefs, scarves, gloves, bags, backpacks, and handbags. In some embodiments, a flame retardant additive can be added to the synthetic polymer textile of the present disclosure to obtain a textile that has flame resistance. The flame retardant additive can for example be a phosphorus based flame retardant.
EXAMPLE 1: BIODEGRADATION ASSAY

[0049] An ASTM D5511 standard test for determining anaerobic biodegradation of plastic materials under high-solids anaerobic-digestion conditions was performed with two polyester textile materials (sample #2 and sample #3) produced according to the present disclosure using a polysaccharide additive. A 100% polyester textile material was used as the negative control and inculum was used as the positive control. Table 1 below summarizes the results after 148 days. Figures 2 and 3 shows the biodegradation curve of percent of biodegradation in function of time. The biodegradation curves observed in Figures 2 and 3 can be extrapolated to a 90 % degradation in 3-4 years.
Table 1: Summary of the results at 148 days ASTM D5511 Date Recue/Date Received 2022-02-07 m InoulLim Negative VIPositive Sample #2 Sample 43 ' Cumulative Gas Volume (mL) 1286.4 1250.9 10217.1 2788.7, 3188.2 Percent CHI (LS:',i , 38.5 33.0 38.4 45.1 45.4 Volume CH4(rnL) 495.7 413.4 3919.0 1258.2 1448.9 Mass CH.i(g) _ 0.35 0.30 2.80 0.90, 1.03 Percent CC): M) 41.6 40.4 43.2 39.8 39.6 _ Volume CO2014 535.7 505.0 4414.9 1111.2 1263.9 Mass CO2(g) 1.05 0.99 8.67 2.18, 2.48 Sample Mass (9) _ 10 10 10 9.5 9.5 Theoretical Sample Mass (g) 0.0 8.6 4.2, 5.9, 5.9 Biodegraded N,,lass (ci) 0.55 0.49 4.46 1.27 1.45 Percent Biode-graded (5,) -0.7 92.7 12.1_ 15.2 EXAMPLE 2: DETECTION OF THE BIODEGRADATION AGENT

[0050] Polyester fibers were produced according to the present disclosure with a polysaccharide as the biodegradation additive. The polysaccharides include but are not limited to starch-based polymers. A portion of the fibers were exposed to iodine which changed color to dark blue indicating the presence of the polysaccharide (such as starch) embedded in the amorphous phase of the polyester fibers (Figure 4).

Date Recue/Date Received 2022-02-07

Claims (17)

WHAT IS CLAIMED IS:

1. A synthetic polymer fibre comprising:
an amorphous phase of at least 10 % of the crystallinity ratio, and 0.1 to 5.0 wt. % of a biodegradation-inducing additive with respect to the total weight of the synthetic polymer fibre, the biodegradation-inducing additive being incorporated in the amorphous phase such that the biodegradation-inducing additive is physically and/or chemically accessible for a biodegradation initiation to form nuclei of biodegradation within the amorphous phase.

2. The synthetic polymer fibre of claim 1, wherein the synthetic polymer fibre is a polyester fibre or a polyamide fibre.

3. The synthetic polymer fibre of claim 1 or 2, wherein the biodegradation-inducing additive is dispersed in the amorphous phase.

4. The synthetic polymer fibre of any one of claims 1 to 3, wherein the synthetic polymer fiber is made of a polymer is selected from poly(butylene succinate) (PBS), poly(butylene succinate)-co-(butylene adipate) (PBSA), poly(E-caprolactone) (PCL), poly(ethylene succinate) (PES), poly(l-lactic acid) (PLA), poly(3-hydroxybutyrate) and poly(3-hydoxybutyrate-co-3-hydroxyvalterate) (PHB/PHBV), poly(ethylene terephthalate) (PET), poly(butylene terephthalate) (PBT), poly(butylene adipate-co-terephthalate (PBAT), poly(butylene succinate-co-terephthalate) (PBST), poly(butylene succinate/terephthalate/isophthalate)-co-(lactate) (PBSTIL), and combinations thereof.

5. The synthetic polymer fibre of any one of claims 1 to 4, wherein the biodegradation-inducing additive is selected from polysaccharide, polylactic acid, polycaprolactone, polybutylene succinate, polybutylene terephthalate-coadipate, furanone, glutaric acids, carboxylic acids, or EcopureTM G2 additive.

6. The synthetic polymer fibre of any one of claims 1 to 5, wherein the biodegradation-inducing additive is a starch-based polymer.
Date Recue/Date Received 2023-04-03

7. The synthetic polymer fibre of any one of claims 1 to 6, wherein the biodegradation-inducing additive is present in a concentration of between 0.5 to 3.0 wt %
with respect to the total weight of the synthetic polymer fibre.

8. The synthetic polymer fibre of any one of claims 1 to 7, wherein the synthetic polymer fibre further comprises a carrier polymer.

9. The synthetic polymer fibre of claim 8, wherein the carrier polymer is selected from wool, flax, cotton, hemp, linen, cellulose, rayon, nylon, and/or silk.

10. The synthetic polymer fibre of any one of claims 1 to 9, wherein a weight ratio of the synthetic polymer fibre to the carrier polymer is between 1:10 to 10:1.

11. The synthetic polymer fibre of any one of claims 1 to 10, further comprising a flame retardant additive.

12. The synthetic polymer fibre of any one of claims 1 to 11, wherein the biodegradation-inducing additive is incorporated in the amorphous phase by physisorption, absorption or adsorption and does not form any intramolecular chemical bonds with the synthetic polymer fibre.

13. A method of fabricating a biodegradable synthetic fibre, comprising:
obtaining the biodegradable synthetic fibre having an extruded synthetic polymer body;
swelling the extruded synthetic polymer body to obtain a swelled extruded synthetic polymer body having an increased surface porosity when compared to the extruded synthetic polymer body; and incorporating a biodegradation-inducing additive into the swelled extruded synthetic polymer body, wherein the biodegradation-inducing additive penetrates pores of the surface of the swelled extruded synthetic polymer body.

14. The method according to claim 13, wherein incorporating the biodegradation-inducing additive is performed in one of a jet dyeing step, a beam dyeing step, a pad application step, or an autoclave purification step.

Date Recue/Date Received 2023-0403

15. The method according to claim 13 or 14, wherein incorporating the biodegradation-inducing additive into the swelled extruded synthetic polymer body includes embedding the biodegradation-inducing additive in an amorphous phase of the swelled extruded synthetic polymer body.

16. The method according to any one of claims 13 to 15, wherein incorporating the biodegradation-inducing additive includes increasing a temperature of the extruded polyester body to a temperature of from 100 to 150 C.

17. The method according to claim 16, wherein the biodegradable synthetic polymer is a biodegradable polyester.

Date Recue/Date Received 2023-0403