Flame retardant copolymers containing one or more non-virgin fossil components and methods for their manufacture - Patents.com

Abstract

The present invention relates to flame-retardant recycled PET (rPET) copolymers incorporating virgin purified terephthalic acid (PTA), virgin dimethyl terephthalate (DMT) and / or virgin fossil monoethylene glycol (MEG)-free (BHET) components, and compositions made by the process, including polymeric materials, polymeric fibrous materials such as those used in the manufacture of nonwoven fabrics, and similar materials.

Description

[Technical Field]

[0001] The present invention relates generally to flame retardant copolymers, and more specifically to copolymers containing one or more non-virgin fossil components in combination with one or more flame retardant monomer chemicals, for use in flame retardant fibers, filaments, and fabrics, where the non-virgin fossil components are derived from recycled, regenerated, or bio-sourced monomers. [Background technology]

[0002] Polymer materials are widely used worldwide and mass-produced industrially. Because they can be engineered with a wide variety of functional and aesthetic properties, the use of polymer materials is increasing significantly year by year. Among these polymer materials, thermoplastic or thermosetting polymer resins are suitable for producing shaped articles from them. One advantage of these materials is their excellent ability to withstand the forces of nature; however, this advantage turns into an environmental disadvantage when they accumulate in waste streams. For example, fibers, such as textile fibers, made from polymer resins are not naturally biodegradable like natural fibers, such as cotton and wool, and may remain in landfills for decades or even longer. Therefore, what makes plastics so attractive also leads to the potential for serious and long-lasting environmental problems.

[0003] Due to the large amount of polymeric materials used worldwide and, in particular, their unsafe release into the natural environment in many countries, waste polymers are accumulating at an alarming rate. Efforts are underway to efficiently convert waste polymers into usable building blocks for producing new polymers.

[0004] The sustainability trend calls for high-performance products with a "green soul" that meet required specifications. The textile industry needs to further address waste and minimize overproduction and the generation of "disposable" items or waste. The term "post-consumer" is overused. The raw materials needed to manufacture textiles can be reprocessed without absolute reliance on fossil fuels. The solution to these problems is twofold: based on advanced recycling and bio-based materials. Advanced recycling is a set of processes and technologies that can address both the reclaiming of waste and the reduction of fossil fuel exploitation. If chemical molecules used in a product can be "released" and reused in a new product, a new "transient state" of the component has been achieved. The performance and aesthetic quality of consumer products manufactured in our industry are important to the market and must perform or function independently of the feedstock used, whether virgin or recovered.

[0005] Among the above-mentioned polymer materials, polycondensates such as polyesters are a class of polymer materials. Among polyesters, polyethylene terephthalate (PET) is widely used for various purposes. Therefore, to overcome the above-mentioned environmental issues, PET recycling has attracted particular attention. One possibility for PET recycling is the separation and recovery of used PET materials. However, due to the presence of various additives in PET, such mechanical recycling has limitations. As a result, chemical recycling of PET is more suitable, allowing for the production of new, customized PET products.

[0006] As described in Patent Document 1, chemical recycling of PET can be carried out by i) acidic or basic hydrolysis, ii) methanolysis, or iii) glycolysis. Method (i) uses water as a reagent with PET, which can produce terephthalic acid (TA) and ethylene glycol (EG) as reaction products (Patent Document 2, 1970). However, this reaction only occurs at high temperatures in the presence of a high concentration of strong acid or base. Method (ii) uses methyl alcohol as a reagent to convert PET to dimethyl terephthalate (DMT) monomer and ethylene glycol. This type of process has been extensively studied, and technology for such a process has been developed. However, PET only reacts with methyl alcohol in the presence of a catalyst at high temperatures (220°C to 250°C) and high pressures (Patent Document 3, 1968). There are risks associated with using methyl alcohol under such extreme conditions. In fact, it is well known that methyl alcohol is highly explosive at high temperatures and pressures. In addition, methyl alcohol is toxic if inhaled or comes into contact with the skin, eyes, etc. In method (iii), waste PET is reacted with ethylene glycol to form a mixture of PET oligomers, which can then be used directly to produce new PET without any purification (Patent Document 4, 1986; Patent Document 5, 1965). This method requires relatively mild reaction conditions (220°C, atmospheric pressure, and the use of EG), but the resulting product is not purified, making it impossible to remove impurities and contaminants (e.g., catalyst residues, dyes, various additives, diethylene glycol, etc.) contained in the waste PET used. Therefore, depolymerization by glycolysis to bis(2-hydroxyethyl) terephthalate (or bishydroxyethyl terephthalate or bisethylene glycol terephthalate) (hereinafter abbreviated as "rBHET") has attracted attention because such BHET can be used as a monomer and polymerized in the production of PET.

[0007] PET derived from BHET as a monomer is produced in one stage, thus using a simpler system than conventional (two-stage) processes. This eliminates the first-stage reactor, avoids the addition of commonly added materials, and eliminates or eliminates the first stage of the process, along with the associated catalyst and its potentially adverse effects. BHET can be used in the polycondensation to PET as a pure, chemically well-defined product, and is a good starting material for producing PET, provided that BHET is free of impurities.

[0008] WO 2021 / 032826 (incorporated herein by reference in its entirety) describes a process for recycling polyethylene terephthalate (PET) into monomer compounds for producing PET. Specifically, bis(2-hydroxyethyl) terephthalate (BHET) can be produced by catalytic glycolysis. However, purification of BHET from crude BHET obtained directly from the depolymerization of PET by glycolysis is complicated.

[0009] WO 2016 / 140901 and U.S. Pat. No. 11,352,718 (each incorporated herein by reference in its entirety) define the terms bio-based or bio-derived monoethylene glycol (bio-MEG) and bio-based or bio-derived purified terephthalic acid (PTA) and their use in PET polymer synthesis.

[0010] PET is used in a variety of products and applications. One application of PET is in the field of flame-retardant fibers and textiles. These flame-retardant textiles are typically manufactured using PET synthesized with components such as PTA and / or MEG from virgin fossil resources, creating a need for flame-retardant modified PET from recycled PET materials. Therefore, there remains an unmet need for the use of recycled waste polymer components and / or bio-sourced polymer components that can substitute or replace traditional virgin fossil or non-degraded polymer component materials in the production of high-quality polymers used in flame-retardant applications. Such materials should be compatible with existing manufacturing technologies and equipment, advantageously reducing the demand for virgin fossil components while avoiding significant capital expenditures.

[0011] Currently, technological advances are opening up the way for future use of non-virgin components derived from recycled, regenerated, bio-sourced, and combinations thereof. The chemistry and methods for obtaining functional flame retardant PET from virgin fossil components by polycondensation are well known and are described, for example, in U.S. Patent Nos. 3,853,819, 4,035,343, and RE30783 (each of which is incorporated herein by reference in its entirety). [Prior art documents] [Patent documents]

[0012] [Patent Document 1] European Patent Application Publication No. 0723951 [Patent Document 2] U.S. Patent No. 3,501,420 [Patent Document 3] U.S. Patent No. 3,403,115 [Patent Document 4] U.S. Patent No. 4,609,680 [Patent Document 5] U.S. Patent No. 3,222,299 Summary of the Invention

[0013] The present invention relates to a method for producing flame-retardant recycled PET (rPET) copolymers by polycondensation of non-virgin fossil-based BHET with a phosphorus-functional comonomer as a flame-retardant functional additive. The invention also encompasses compositions made by the method, including polymeric materials, polymeric fibrous materials such as those used to make nonwoven fabrics, and similar materials, and fabrics comprising such polymeric fibrous materials.

[0014] Other features and advantages of the present invention will become apparent from the following more detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] The present invention provides a flame-retardant recycled PET (rPET) copolymer obtained by polycondensation of non-virgin fossil-based BHET with a phosphorus-functional comonomer as a flame-retardant additive. In the present invention, the non-virgin fossil-based BHET is the monomer rBHET. In addition, the use of the monomer rBHET allows for the tailoring and tailoring of various parameters of the flame-retardant recycled PET (rPET) copolymer obtained according to the present invention. This is usually only partially possible with significant changes to the manufacturing process involved or other additional measures that increase manufacturing costs.

[0016] In a preferred embodiment, the present invention provides a flame-retardant recycled PET (rPET) copolymer by polycondensation of i) the monomer rBHET and ii) a phosphorus-functional comonomer without any addition of a) virgin fossil purified terephthalic acid (PTA), or b) virgin fossil dimethyl terephthalate (DMT), or c) virgin fossil monoethylene glycol (MEG). The flame-retardant recycled PET (rPET) copolymer obtained using the monomer rBHET can be specifically tailored and designed with respect to various parameters. This is usually only partially possible, particularly requiring significant modifications of the commercial manufacturing processes involved or other additional measures that increase production costs.

[0017] Purified terephthalic acid (PTA) is so-called "fiber-pure" terephthalic acid (PTA), which contains less than 25 ppm of 4-CBA (4-carboxybenzaldehyde) and has a purity of more than 99.99%.

[0018] Generally, fossil materials can be easily distinguished from materials of bio-based or bio-derived sources by their carbon-14 (C14) isotope patterns.

[0019] Virgin fossil refined terephthalic acid (PTA) is PTA obtained starting from fossil resources, such as crude oil or natural gas, and is not a bio-based or bio-derived material as defined in WO 2016 / 140901 and U.S. Pat. No. 11,352,718 (each of which is incorporated herein by reference in its entirety and defines the terms bio-based or bio-derived). Fossil PTA can be readily distinguished from PTA from bio-based or bio-derived sources by its carbon-14 (C14) isotope pattern.

[0020] Virgin fossil dimethyl terephthalate (DMT) is DMT obtained starting from fossil resources, such as crude oil or natural gas, and is not a bio-based or bio-derived material as defined in WO 2016 / 140901 and U.S. Pat. No. 11,352,718 (each of which is incorporated herein by reference in its entirety and defines the terms bio-based or bio-derived). Fossil DMT can be readily distinguished from DMT from bio-based or bio-derived sources by its carbon-14 (C14) isotope pattern.

[0021] Virgin fossil monoethylene glycol (MEG) is MEG obtained starting from fossil resources, such as crude oil or natural gas, and is not bio-based or bio-derived monoethylene glycol (bio-MEG) as defined in WO 2016 / 140901 and U.S. Pat. No. 11,352,718 (each of which is incorporated herein by reference in its entirety and defines the terms bio-based or bio-derived). Fossil MEG can be readily distinguished from MEG from bio-based or bio-derived sources by its carbon-14 (C14) isotope pattern.

[0022] In a further embodiment, the present invention relates to a process that further utilizes a non-antimony catalyst, such that the possibility of further inclusion of antimony in the resulting flame retardant rPET copolymer is eliminated.

[0023] The phosphorus-functional comonomer used as a flame-retardant additive in the present invention can be any phosphorus- or phosphorous-based comonomer that provides such flame-retardant functionality and can be used in the polycondensation of rBHET. Suitable phosphorus- or phosphorous-based comonomers are described in U.S. Patents 3,853,819, 4,035,343, and RE30783.

[0024] Preferred phosphorus-functional comonomers are represented by formula (I) and / or formula (II): TIFF2026503257000001.tif75170, where the radicals have the following meanings: R 1 is alkyl, aryl, alkyl-aryl, aryl-alkyl, preferably C1-C 10 -Alkyl or C6-C 10 -aryl, more preferably CH3 or C6H5; R 2 Ha-(CH2) x - and x is an integer from 1 to 6, preferably x=2; R 3 , R 4is H, -(CH2) y -OH, (CH2) z -O-(CH2) z OH, preferably (CH)-OH, (CH)-O-(CH)OH, CH-CH-CH-CHOH, CH-CH-CHOH, y is an integer of 1 to 6, preferably 1 to 4; and z is an integer of 1 to 6, preferably 1 to 4, and more preferably 2).

[0025] A particularly preferred phosphorus-functional comonomer is 3-(hydroxyphenylphosphinyl)propanoic acid (3-HPP): The file is TIFF2026503257000002.tif35170.

[0026] The phosphorus-functional comonomer is present in the flame retardant recycled PET (rPET) copolymer in an amount ranging from 0.01 wt % to 3 wt % phosphorus content based on the total weight of the polymeric material.

[0027] The use of rBHET with a defined profile allows for the tailoring and control of various parameters of the flame-retardant recycled PET (rPET) copolymers obtained according to the present invention. This is usually only partially possible, particularly requiring significant modifications of the commercial manufacturing processes involved or other additional measures that increase production costs. Therefore, the use of the present monomer rBHET allows for the tailoring and control of the properties of the flame-retardant recycled PET (rPET) copolymers thus obtained.

[0028] The monomeric rBHET materials used in the present invention are (i) at least 75% by weight bis(2-hydroxyethyl) terephthalate (BHET), preferably at least 90% by weight bis(2-hydroxyethyl) terephthalate (BHET), based on the dry weight of the monomeric BHET material; (ii) 0.3% to 8% by weight of mono(2-hydroxyethyl) terephthalate (MHET), preferably 0.3% to 2.5% by weight of mono(2-hydroxyethyl) terephthalate (MHET), based on the dry weight of the monomeric rBHET material; (iii) 1 wt. % to 20 wt. % of a linear oligomer, preferably 1 wt. % to 8 wt. % of a linear oligomer, based on the dry weight of the monomeric rBHET material; (iv) optionally, 0.001% to 0.1% by weight of a cyclic oligomer, based on the dry weight of the monomeric rBHET material; (v) a carboxyl end group (CEG) content of 8 mmol / kg to 70 mmol / kg, preferably 15 mmol / kg to 50 mmol / kg; (vi) a saponification value corresponding to a range of 430 mg KOH / g to 450 mg KOH / g; (vii) 0.1 wt% to 2.5 wt%, preferably 0.1 wt% to 2.0 wt%, more preferably 0.5 wt% to 1.6 wt% of diethylene glycol (DEG); Includes.

[0029] By using the above-described monomer rBHET, it is possible to produce flame-retardant recycled PET (rPET) copolymers having a low residual diethylene glycol (DEG) content of less than 1.45 wt.%, preferably 1.4 wt.% or less, more preferably 1.3 wt.% or less, and more preferably 1.2 wt.% or less, based on the weight of the final flame-retardant recycled PET (rPET) copolymer. In contrast, commercially available flame-retardant PET copolymers typically have a residual diethylene glycol (DEG) content of 1.48 wt.% to 1.5 wt.% residual diethylene glycol (DEG).

[0030] Additionally, it is surprising that the use of the above-mentioned monomer rBHET allows for even higher phosphorous acid contents in the flame-retardant recycled PET (rPET) copolymers, and the presence of such phosphorous acid materials also contributes to the formation of residual diethylene glycol (DEG) in the polymer. Thus, by using the above-mentioned monomer rBHET containing up to 2.5 wt. %, preferably 1.5 wt. % to 2.5 wt. %, more preferably 1.8 wt. % to 2.5 wt. %, of diethylene glycol (DEG), flame-retardant recycled PET (rPET) copolymers having phosphorous acid contents of at least 6700 mg / kg are possible, preferably such flame-retardant recycled PET (rPET) copolymers having melting temperatures below 242°C, particularly below 240°C.

[0031] Additionally, for specific purposes, a higher residual diethylene glycol (DEG) content may be desired in flame-retardant PET copolymers. This can also be controlled by using the monomer rBHET with the above set of parameters to produce flame-retardant recycled PET (rPET) copolymers with higher residual diethylene glycol (DEG) content, except that the higher DEG content ranges from 1.5 wt% to a maximum of 8 wt% DEG.

[0032] Furthermore, by selecting the diethylene glycol (DEG) content of the monomer rBHET in combination with a range of other parameters, it is possible to obtain flame retardant recycled PET (rPET) copolymers with improved dyeability of the fibers obtained from the flame retardant recycled PET (rPET) copolymers, which further controls the subsequent dyeing process of the fibers formed from such flame retardant recycled PET (rPET) copolymers.

[0033] In the production of known flame-retardant PET copolymers, diethylene glycol (DEG) is primarily formed during the esterification reaction, which is typically under acidic conditions. While process conditions can be adapted or modified to control the DEG content, this is a complex operation, leading to potential quality deviations in the final product as well as increased costs in commercial operations. Therefore, the present monomer designated rBHET offers a controlled route to producing flame-retardant recycled PET (rPET) copolymers.

[0034] Typically, the diethylene glycol (DEG) content in the production of known flame-retardant PET copolymers is about 1.48 wt% to 1.5 wt% DEG. This residual diethylene glycol (DEG) content affects the dyeability of fibers obtained from such materials, among other properties. In the present invention, the use of the present monomer rBHET allows the residual diethylene glycol (DEG) content to be set from the beginning.

[0035] To obtain flame retardant recycled PET (rPET) copolymers with higher residual DEG amounts (greater than 1.6 wt% DEG), a diethylene glycol (DEG) content of the monomer rBHET of at least 1.5 wt%, more preferably 1.6 wt%, is selected in combination with a range of other parameters.

[0036] To obtain flame-retardant recycled PET (rPET) copolymers with lower residual DEG content (less than 1.4 wt% DEG), the diethylene glycol (DEG) content of the monomer rBHET is selected from 0.1 wt% to 1 wt%, in combination with a range of other parameters.

[0037] The monomer rBHET used in the present invention preferably has a moisture (water) content of at most 3 wt%, more preferably at most 2 wt%.

[0038] The monomeric rBHET used in the present invention preferably has a crystallinity of at least 80%, more preferably at least 90%, and most preferably at least 95%, based on the dry weight of the monomeric rBHET material. The use of monomeric rBHET with such a crystallinity reduces the risk of breakage and / or deformation during handling, as well as the formation of agglomerates.

[0039] The rBHET monomer used in the present invention preferably has a particle size in the range of 0.1 mm to 10 mm, more preferably 0.5 mm to 8 mm, and particularly preferably 3 mm to 7 mm. By additionally selecting a particle size within the above range for the rBHET monomer, it is possible to control the melting behavior of the rBHET monomer and the residence time in a reactor, particularly a polycondensation reactor, during the production of flame-retardant recycled PET (rPET).

[0040] The flame-retardant recycled PET (rPET) copolymers of the present invention are produced by melting the monomer rBHET in a stirred tank under ambient pressure, typically at a temperature of about 110°C to 140°C. Additives such as catalysts, matting agents, other functional additives, and phosphorus-functional comonomers are then added to the molten rBHET in the stirred tank, typically with stirring. The temperature is then increased to about 250°C, and the hot reaction mixture is discharged into a polycondensation tank. The pressure in the polycondensation tank is typically reduced to about 100 mbar, and volatile components and volatile ethylene glycol are removed, typically with stirring. After ethylene glycol removal is complete, the temperature of the polycondensation tank is increased to about 280°C, and the pressure is further reduced, typically to about 1 mbar or less. Polycondensation is completed until the target torque on the agitator is reached. The flame retardant recycled PET (rPET) copolymer is discharged from the polycondensation tank and either extruded into chips or fed directly into a melt spinning unit to melt the flame retardant recycled PET (rPET) copolymer fibers.

[0041] The flame retardant recycled PET (rPET) copolymers of the present invention have the following set of parameters: (i) a carboxyl end group (CEG) content of 8 mmol / kg to 70 mmol / kg, preferably 15 mmol / kg to 50 mmol / kg, and (ii) less than 1.45 wt.% diethylene glycol (DEG); (iii) A molecular weight corresponding to an intrinsic viscosity (IV) of 0.4 dl / g to 1.6 dl / g measured in solution in dichloroacetic acid at 25°C.

[0042] If a material meets the requirements of DIN 4102B1, it is considered flame retardant.

[0043] The flame-retardant recycled PET (rPET) copolymers obtained from the present monomer rBHET have a controlled residual diethylene glycol (DEG) content, or in other words, the DEG content can be adjusted by selecting the appropriate monomer rBHET raw material.

[0044] A further subject of the invention is therefore (i) at least 75% by weight bis(2-hydroxyethyl) terephthalate (BHET), preferably at least 90% by weight bis(2-hydroxyethyl) terephthalate (BHET), based on the dry weight of the monomeric BHET material; and (ii) 0.3% to 8% by weight of mono(2-hydroxyethyl) terephthalate (MHET), preferably 0.3% to 2.5% by weight of mono(2-hydroxyethyl) terephthalate (MHET), based on the dry weight of the monomeric rBHET material; and (iii) 1 wt% to 20 wt% of a linear oligomer, based on the dry weight of the monomeric rBHET material; and (iv) optionally, 0.001% to 0.1% by weight of a cyclic oligomer, based on the dry weight of the monomeric rBHET material; and (v) a carboxyl end group (CEG) content of 8 mmol / kg to 70 mmol / kg, preferably 15 mmol / kg to 50 mmol / kg, and (vi) a saponification value corresponding to a range of 430 mg KOH / g to 450 mg KOH / g; and (vii) 0.1 wt% to 2.5 wt%, preferably 0.1 wt% to 2.0 wt%, more preferably 0.5 wt% to 1.6 wt% of diethylene glycol (DEG); a monomeric rBHET material comprising: Formula (I) and / or Formula (II): TIFF2026503257000003.tif75170, where the radicals have the following meanings: R 1 is alkyl, aryl, alkyl-aryl, aryl-alkyl, preferably C1-C 10 -Alkyl or C6-C 10 -aryl, more preferably CH3 or C6H5; R 2 Ha-(CH2) x - and x is an integer from 1 to 6, preferably x=2; R 3 , R 4 is H, -(CH2) y -OH, (CH2) z -O-(CH2) z OH, preferably (CH)-OH, (CH)-O-(CH)OH, CH-CH-CH-CHOH, CH-CH-CHOH, y is an integer of 1 to 6, preferably 1 to 4; z is an integer from 1 to 6, preferably from 1 to 4, and more preferably z is 2; and by mixing and polycondensation of (i) a carboxyl end group (CEG) content of 8 mmol / kg to 70 mmol / kg, preferably 15 mmol / kg to 50 mmol / kg, and (ii) less than 1.45 wt. % diethylene glycol (DEG); and (iv) a molecular weight corresponding to an intrinsic viscosity (IV) of 0.4 dL / g to 1.6 dL / g, as measured in solution in dichloroacetic acid at 25°C; and (vi) having a phosphorus content of 0.01 wt % to 3 wt %, based on the total weight of the polymeric material; (vii) the phosphorus content is covalently attached to the polymer backbone; It is a flame-retardant recycled PET (rPET) copolymer having the following properties.

[0045] By using the above-described monomer rBHET, it is possible to produce flame-retardant recycled PET (rPET) copolymers having a low residual diethylene glycol (DEG) content of less than 1.45 wt.%, preferably 1.4 wt.% or less, more preferably 1.3 wt.% or less, and more preferably 1.2 wt.% or less, based on the weight of the final flame-retardant recycled PET (rPET) copolymer. In contrast, commercially available flame-retardant PET copolymers typically have a residual diethylene glycol (DEG) content of 1.48 wt.% to 1.5 wt.% residual diethylene glycol (DEG).

[0046] Additionally, it is surprising that the use of the above-mentioned monomer rBHET allows for even higher phosphorous acid contents in the flame-retardant recycled PET (rPET) copolymers, and the presence of such phosphorous acid materials also contributes to the formation of residual diethylene glycol (DEG) in the polymer. Thus, by using the above-mentioned monomer rBHET containing up to 2.5 wt. %, preferably 1.5 wt. % to 2.5 wt. %, more preferably 1.8 wt. % to 2.5 wt. %, of diethylene glycol (DEG), flame-retardant recycled PET (rPET) copolymers having phosphorous acid contents of at least 6700 mg / kg are possible, preferably such flame-retardant recycled PET (rPET) copolymers having melting temperatures below 242°C, particularly below 240°C.

[0047] Generally, polymer properties such as melting behavior, crystallization behavior, crystallinity, etc. can be controlled by controlling the DEG content in the polymer. In addition, the dyeability of fibers obtained from such flame-retardant recycled PET (rPET) copolymers can be controlled and tailored by selecting the DEG content of the rBHET monomer used to produce the flame-retardant recycled PET (rPET) copolymer. This allows the DEG content of the flame-retardant recycled PET (rPET) copolymer to be selected and controlled, as the residual DEG content affects various polymer properties, including the dyeability of fibers obtained from such materials.

[0048] In principle, the monomer rBHET is available from Ioniqa, with offices at De Lismortel 31, 5612 AR Eindhoven, The Netherlands, or from JEPLAN Co., Ltd., with offices at 12-2 Ogimachi, Kawasaki-ku, Kawasaki-shi, 210-0867, Japan.

[0049] Preferably, the entire formation of the flame retardant recycled PET (rPET) copolymer is in the absence of virgin fossil PTA or virgin fossil MEG.

[0050] In a preferred embodiment, the rBHET is obtained from using bio-based and / or recycled MEG to glycolyze recycled PET, as defined in WO 2016 / 140901 and U.S. Pat. No. 11,352,718 (each of which is incorporated herein by reference in its entirety for purposes of defining the terms bio-based or bio-derived).

[0051] In a preferred embodiment, rBHET is reacted in the presence of bio-derived and / or recycled PTA, as defined in WO 2016 / 140901 and U.S. Pat. No. 11,352,718, each of which is incorporated herein by reference in its entirety for purposes of defining the terms bio-based or bio-derived.

[0052] In a preferred embodiment, rBHET is reacted in the presence of bio-derived and / or recycled DMT, as defined in WO 2016 / 140901 and U.S. Pat. No. 11,352,718, each of which is incorporated herein by reference in its entirety for purposes of defining the terms bio-based or bio-derived.

[0053] Equipment useful for preparing the composite constructions of fibrous materials of the present invention is conventional in nature and known to those skilled in the art, and includes extruders, spinners, drawing godets, ovens, coolers, conveying lines, water / air injectors, winders / rewinders or unwinders, topical applicators, calenders, compactors, balers / openers, and the like.

[0054] The inventors have succeeded in designing the manufacturing process with maximum flexibility to use natural, non-nutritional bio-based feedstocks and / or utilize highly recycled PET waste streams. It is important to track and take into account the entire value-added chain of textiles and their raw materials, as well as the potential for fabric recovery to treat post-consumer fabrics as valuable raw materials for further reuse.

[0055] This invention describes a successful first step toward the development of a commercial-scale circular textile economy focused on flame-retardant man-made fibers and yarns. This three-stage holistic approach includes one of several exemplary processes: 1. rPET production using a blend of recycled and biosourced raw materials (pre-life); 2. Applying this rPET, modified with a stable flame-retardant polymer, to environmentally friendly, high-performance textiles; and 3. A recovery system to ensure the return of raw materials as feedstock to the next manufacturing process—together forming a circular economy (post-life). Additionally, this invention provides a route to flame-retardant recycled PET (rPET) copolymers with lower or higher residual diethylene glycol (DEG) content than flame-retardant PET from current commercial processes. Furthermore, by using the above-mentioned monomer rBHET, even higher phosphorous acid content in the flame-retardant recycled PET (rPET) copolymers is possible, e.g., phosphorous content of 0.7 wt% or more based on the total weight of the polymeric material. Surprisingly, the presence of such phosphorous acid materials also contributes to the formation of residual diethylene glycol (DEG) in the polymer.

[0056] Although the preferred embodiment of the present invention is for flame-retardant rPET that is composed entirely or predominantly of either fully recycled and / or bio-based components, it is understood that blends of virgin (e.g., PTA or MEG) and non-virgin (e.g., PTA or MEG) components can be utilized in many different applications.

[0057] Flame retardant rPET can be supplied in a variety of forms, such as pellets, chips, flakes, etc., for conversion into various thermoplastic constructions, including molding, extrusion, spraying, or other methods.

[0058] The resulting flame retardant rPET of the present invention can be used as a fiber to make textile fabrics such as woven, knitted, nonwoven and / or cloth, including blends, laminates, composites, which have the same or different flame retardant properties depending on the resulting fabric material.

[0059] It is understood that the present flame retardant rPET compositions, particularly as fibers, are not constrained by a particular cross-sectional profile, and it is contemplated by the present invention that the resulting polymeric materials may have circular, oval, and other suitable cross-sections, such as star-shaped, or even other shapes, such as dumbbell-shaped, kidney-shaped, octapous and dog-bone-shaped, triangular, or trilobal or multilobal cross-sections. Hollow variations and blends of cross-sectional profiles are also possible.

[0060] The polymer compositions of the present invention can be produced by melt-spinning a first polymer blend and a second polymer blend to form a composite fibrous material having multiple fibrous components. This form of fibrous material is sometimes referred to as bicomponent or multicomponent and can take many configurations, including sheath / core cross-sectional configurations, side-by-side configurations, segmented pie or split configurations, so-called "islands-in-the-sea" configurations, and other arrangements and blends thereof, including the use of monocomponent cross-sectional configurations.

[0061] The polymer compositions of the present invention may be formed from a blend of two or more polymers, and the additives to each polymer may be different, including copolymers and alloys.

[0062] The one or more polymers may have different levels of functional additives (e.g., flame retardants) or compositions, blends of different functional additives (two or more flame retardant additives), or may contain different levels of one or more secondary functional (such as antimicrobials, friction modifiers, adsorbents or absorbents, and skin wellness) and / or aesthetic (such as pigments, matting agents, and opacifiers) additives or compositions. Additionally, the resulting material produced by the polycondensation reaction may optionally undergo one or more separate processes to impart additional functional and / or aesthetic modifications to the original flame retardant material, including, but not limited to, treating the material with secondary flame retardant chemistries or techniques.

[0063] The flame-retardant rPET copolymers of the present invention are feedstocks for melt-spinning flame-retardant rPET copolymer fibers. Such melt-spinning produces continuous filaments of the flame-retardant rPET copolymer, which can be chopped into staple fibers or drawn into strong filaments by established drawing processes. Furthermore, the flame-retardant rPET copolymer fibers are useful for forming yarns, woven fabrics, and nonwoven fabrics, including nonwovens.

[0064] Flame retardant rPET copolymer fibers are useful for the production of nonwovens, wovens, knitted fabrics, etc., as well as corresponding ready-made articles such as textiles for clothing and underwear, sports textiles, home textiles and bedding, hygiene and medical textiles, automotive textiles, aerospace textiles, food packaging, industrial textiles for construction and filtration, towels, etc.

[0065] The textile products are produced by methods well known to those skilled in the art, i.e., woven fabrics and formed-loop knitted fabrics are produced using conventional machinery, and nonwoven fabrics can be produced, for example, from staple or continuous filament fibers, here by, for example, the spunbond process. The nonwoven, woven and knitted fabrics according to the invention can also be processed to form laminates or composites, and can also form shaped articles.

[0066] Because the flame-retardant functionality of flame-retardant rPET copolymer fibers is incorporated into the polymer backbone via covalent chemical bonds, the flame-retardant properties are permanent and diminish only minimally with washing and wear. In contrast, flame-retardant functionality added later to the fiber, such as by sizing, diminishes significantly more rapidly with washing and wear. Co-condensed phosphorus compounds are incorporated into the polymer backbone via covalent chemical bonds and are not migratory, significantly reducing, if any, the allergenic potential.

[0067] The flame retardant rPET copolymer fibers are in the form of staple fibers, filaments, and monofilaments for constructing the respective textiles.

[0068] The flame-retardant rPET copolymer fibers can be composed entirely of flame-retardant rPET copolymers with co-condensed phosphorus-containing chain members. In a further embodiment, it is also possible to use so-called multicomponent fibers.

[0069] Multicomponent fibers combine several different materials into one fiber. Examples are bicomponent fibers configured as sheath-core fibers or side-by-side fibers. In such an arrangement, some of the side-by-side filaments, or the sheath in the case of sheath-core fibers, consist of the flame-retardant rPET copolymer, while the other components typically have melting points at least 5°C lower, more preferably at least 10°C lower, than the melting point of the flame-retardant rPET copolymer, providing thermo-bonding of the fibrous material.

[0070] Particularly advantageous for the purposes of the present invention are textile products comprising a flame-retardant rPET copolymer as the sheath material of sheath-core fibers, the sheath component representing up to 50%, in particular 15% to 50%, preferably 15% to 25%, of the area cross-section of the multicomponent fiber.

[0071] In a further embodiment of the present invention, the flame-retardant rPET copolymer fibers are used as so-called hybrid fibers or yarns. These hybrid fibers or yarns consist of several, preferably two, polymer components, one of which has a melting point at least 10° C. lower than the other. At least one of the aforementioned components is a flame-retardant rPET copolymer fiber according to the present invention.

[0072] The production of corresponding flame-retardant polyester fibers, in which the polyester contains co-condensed phosphorus-containing chain components, is known per se. Reference is made here to the following German patent applications or patent specifications, the disclosure content of which is expressly incorporated herein by reference: DE-A-2,236,037, DE-A-2,242,002, DE-A-2,346,787, DE-A-2,454,189. [Example]

[0073] BHET material samples used:

[0074] TIFF2026503257000004.tif35170

[0075] Example 1 FR (Flame Retardant), 100% BHET Material H The BHET is placed in a steel vessel and heated to 110°C at ambient pressure. During the temperature increase to 140°C, the BHET melts. Antimony glycolate dissolved in MEG, TiO2 as a slurry in MEG, and 3-(hydroxyphenylphosphinyl)propanoic acid (3-HPP) (50%) dissolved in MEG are added. The reaction temperature is then increased to 250°C and transferred to a polycondensation vessel. The pressure in the reactor is then reduced to 100 mbar until all excess MEG is removed. Polycondensation is then carried out at 280°C at a pressure of less than 1 mbar. After the target agitator torque level is reached, the reactor is discharged.

[0076] TIFF2026503257000005.tif47170

[0077] TIFF2026503257000006.tif26170

[0078] Example 2 Fiber spinning Flame retardant rPET copolymers are melt spun into flame retardant rPET copolymer fibers using existing commercially available equipment and methods known to those skilled in the art using the polymer of Example 1. For details, see, for example, U.S. Patent No. 3,816,486, U.S. Patent No. 4,639,347, British Patent No. 1,254,826, and Japanese Patent Application Laid-Open No. 11-189938.

Claims

1. Flame retardant recycled PET (rPET) copolymer obtained by polycondensation of non-virgin fossil-based BHET with phosphorus-functional comonomer as a flame retardant functional additive.

2. 2. The flame retardant recycled PET (rPET) copolymer of claim 1, wherein the non-virgin fossil-based BHET is monomeric rBHET.

3. 3. The flame retardant recycled PET (rPET) copolymer of claim 2, wherein the flame retardant recycled PET (rPET) copolymer is obtained by polycondensation of i) the monomer rBHET and ii) a phosphorus-functional comonomer without any addition of a) virgin fossil refined terephthalic acid (PTA), or b) virgin fossil dimethyl terephthalate (DMT), or c) virgin fossil monoethylene glycol (MEG).

4. The flame retardant recycled PET (rPET) copolymer of any one of claims 1 to 3, wherein the flame retardant functional additive is incorporated into the polymer backbone by a covalent chemical bond.

5. The flame retardant functional additive is represented by formula (I) and / or formula (II): wherein the radicals have the following meanings: R １ is alkyl, aryl, alkyl-aryl, aryl-alkyl, preferably C １ ~C １０ -Alkyl or C ６ ~C １０ -aryl, more preferably CH ３ or C ６ H ５ and R ２ Ha-(CH ２ ) ｘ - and x is an integer from 1 to 6, preferably x=2; R ３ , R ４ is H, -(CH ２ ) ｙ -OH, (CH ２ ) ｚ -O-(CH ２ ) ｚ OH, preferably (CH ２ ) ２ -OH, (CH ２ ) ２ -O-(CH ２ ) ２ OH, CH ２ -CH ２ -CH ２ -CH ２ OH, CH ２ -CH ２ -CH ２ OH, y is an integer from 1 to 6, preferably from 1 to 4; wherein z is an integer from 1 to 6, preferably from 1 to 4, and more preferably z is 2.

6. The flame retardant recycled PET (rPET) copolymer of any one of claims 1 to 5, wherein the flame retardant functional additive is 3-(hydroxyphenylphosphinyl)propanoic acid (3-HPP).

7. 7. The flame retardant recycled PET (rPET) copolymer of any one of claims 1 to 6, wherein the flame retardant functional additive is present in an amount ranging from 0.01 wt% to 3 wt% phosphorus content, based on the total weight of the polymeric material.

8. The monomeric rBHET material is (i) at least 75% by weight bis(2-hydroxyethyl) terephthalate (BHET), preferably at least 90% by weight bis(2-hydroxyethyl) terephthalate (BHET), based on the dry weight of said monomeric BHET material; (ii) 0.3% to 8% by weight of mono(2-hydroxyethyl) terephthalate (MHET), preferably 0.3% to 2.5% by weight of mono(2-hydroxyethyl) terephthalate (MHET), based on the dry weight of the monomeric rBHET material; (iii) 1% to 20% by weight of a linear oligomer, preferably 1% to 8% by weight of a linear oligomer, based on the dry weight of the monomeric rBHET material; (iv) optionally, 0.001% to 0.1% by weight of a cyclic oligomer, based on the dry weight of the monomeric rBHET material; (v) a carboxyl end group (CEG) content of 8 mmol / kg to 70 mmol / kg, preferably 15 mmol / kg to 50 mmol / kg; (vi) a saponification value corresponding to a range of 430 mg KOH / g to 450 mg KOH / g; (vii) 0.1 wt % to 2.5 wt %, preferably 0.1 wt % to 2.0 wt %, more preferably 0.5 wt % to 1.6 wt % of diethylene glycol (DEG); The flame retardant recycled PET (rPET) copolymer of any one of claims 2 to 7, comprising:

9. 9. The flame retardant recycled PET (rPET) copolymer according to any one of claims 1 to 8, wherein the flame retardant recycled PET (rPET) copolymer has a low residual diethylene glycol (DEG) content of less than 1.45 wt%, preferably 1.4 wt% or less, more preferably 1.3 wt% or less, more preferably 1.2 wt% or less, based on the weight of the final flame retardant recycled PET (rPET) copolymer.

10. 9. The flame retardant recycled PET (rPET) copolymer according to any one of claims 1 to 8, wherein the flame retardant recycled PET (rPET) copolymer has a phosphorous acid content of at least 6700 mg / kg by using a monomer rBHET as defined in claim 8, which monomer rBHET comprises a maximum of 2.5 wt.%, preferably 1.5 wt.% to 2.5 wt.%, more preferably 1.8 wt.% to 2.5 wt.% of diethylene glycol (DEG), and wherein preferably the flame retardant recycled PET (rPET) copolymer has a melting temperature below 242°C, in particular below 240°C.

11. 11. The flame retardant recycled PET (rPET) copolymer according to any one of claims 2 to 10, wherein the monomer rBHET has a moisture (water) content of at most 3 wt%, more preferably at most 2 wt%.

12. 12. The flame retardant recycled PET (rPET) copolymer according to any one of claims 2 to 11, wherein the monomer rBHET has a particle size in the range of 0.1 mm to 10 mm, more preferably 0.5 mm to 8 mm, and particularly preferably 3 mm to 7 mm.

13. The flame-retardant recycled PET (rPET) copolymer comprises: (i) a carboxyl end group (CEG) content of 8 mmol / kg to 70 mmol / kg, preferably 15 mmol / kg to 50 mmol / kg; (ii) less than 1.45 wt. % diethylene glycol (DEG); (iii) a molecular weight corresponding to an intrinsic viscosity (IV) of 0.4 dL / g to 1.6 dL / g, as measured in solution in dichloroacetic acid at 25°C; The flame retardant recycled PET (rPET) copolymer of any one of claims 1 to 11, having

14. (i) at least 75% by weight bis(2-hydroxyethyl) terephthalate (BHET), preferably at least 90% by weight bis(2-hydroxyethyl) terephthalate (BHET), based on the dry weight of the monomeric BHET material; and (ii) 0.3% to 8% by weight of mono(2-hydroxyethyl) terephthalate (MHET), preferably 0.3% to 2.5% by weight of mono(2-hydroxyethyl) terephthalate (MHET), based on the dry weight of the monomeric rBHET material; and (iii) 1% to 20% by weight of a linear oligomer, based on the dry weight of the monomeric rBHET material; and (iv) optionally, 0.001% to 0.1% by weight of a cyclic oligomer, based on the dry weight of the monomeric rBHET material; and (v) a carboxyl end group (CEG) content of 8 mmol / kg to 70 mmol / kg, preferably 15 mmol / kg to 50 mmol / kg; and (vi) a saponification value corresponding to a range of 430 mg KOH / g to 450 mg KOH / g; and (vii) 0.1% to 2.5% by weight, preferably 0.1% to 2.0% by weight, more preferably 0.5% to 1.6% by weight of diethylene glycol (DEG); a monomeric rBHET material comprising: Formula (I) and / or Formula (II): wherein the radicals have the following meanings: R １ is alkyl, aryl, alkyl-aryl, aryl-alkyl, preferably C １ ~C １０ -Alkyl or C ６ ~C １０ -aryl, more preferably CH ３ or C ６ H ５ and R ２ Ha-(CH ２ ) ｘ - and x is an integer from 1 to 6, preferably x=2; R ３ , R ４ is H, -(CH ２ ) ｙ -OH, (CH ２ ) ｚ -O-(CH ２ ) ｚ OH, preferably (CH ２ ) ２ -OH, (CH ２ ) ２ -O-(CH ２ ) ２ OH, CH ２ -CH ２ -CH ２ -CH ２ OH, CH ２ -CH ２ -CH ２ OH, y is an integer from 1 to 6, preferably from 1 to 4; z is an integer from 1 to 6, preferably from 1 to 4, and more preferably z is 2; obtained by mixing and polycondensation of (i) a carboxyl end group (CEG) content of 8 mmol / kg to 70 mmol / kg, preferably 15 mmol / kg to 50 mmol / kg; and (ii) less than 1.45 wt. % diethylene glycol (DEG); and (iii) a molecular weight corresponding to an intrinsic viscosity (IV) of 0.4 dl / g to 1.6 dl / g, measured in solution in dichloroacetic acid at 25°C; (vi) having a phosphorus content of 0.01 wt % to 3 wt % based on the total weight of the polymeric material; (vii) the phosphorus content is covalently attached to the polymer backbone; A flame retardant recycled PET (rPET) copolymer having

15. A method for producing a flame retardant recycled PET (rPET) copolymer, comprising polycondensation of non-virgin fossil-based rBHET with a phosphorus-functional comonomer as a flame retardant functional additive.

16. 16. The method of claim 15, wherein the polycondensation is carried out with i) the monomer rBHET and ii) a phosphorus-functional comonomer without any addition of a) virgin fossil purified terephthalic acid (PTA), or b) virgin fossil dimethyl terephthalate (DMT), or c) virgin fossil monoethylene glycol (MEG).

17. 17. The method according to claim 15 or 16, wherein the flame retardant functional additive is as defined in claims 4 to 7 and the monomer rBHET is as defined in claims 8, 11 and 12.

18. 17. The method according to claim 15 or 16, wherein the flame retardant functional additive is as defined in claims 4 to 7 and the monomer rBHET is as defined in claims 8, 11 and 12.

19. A melt-spun fiber comprising the flame retardant rPET copolymer of any one of claims 1 to 14.

20. A textile fabric, preferably a nonwoven or woven or knitted fabric, comprising fibres comprising the flame retardant rPET copolymer according to any one of claims 1 to 14.

21. 15. Use of textile fabrics comprising fibers comprising the flame retardant rPET copolymer of any one of claims 1 to 14 in the manufacture of ready-made articles such as textiles for clothing and underwear, sports textiles, window coverings, wallpaper, household textiles and bedding such as carpets and mattresses, hygiene and medical textiles, automotive textiles, aerospace textiles, food packaging, industrial textiles for construction and filtration, towels, and personal protective equipment.

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