DESC:FIELD
The present disclosure relates to a process for reducing the fluoroalkyl substances from a fluoropolymer latex.
DEFINITIONS
As used in the present disclosure, the following terms are generally intended to have the meaning as set forth below, except to the extent that the context in which they are used indicate otherwise.
Fluoroalkyl substances (PFAS): The term “fluoroalkyl substances” also known as “perfluoroalkyl and polyfluoroalkyl substance” abbreviated as PFAS, refers to a group of synthetic organofluorine chemical compounds that have one or multiple fluorine atoms attached to an alkyl chain.
Ion exchange: The term “ion exchange” refers to a process in which one kind of ion present in an insoluble solid is reversibly interchanged with another kind of ion present in a solution surrounding the solid, which may result in purified solution.
Latex: The term “latex” refers to a stable colloidal dispersion of polymer particles in a liquid medium.
Targeted fluoroalkyl substance: The term “targeted fluoroalkyl substance” also known as “targeted PFAS” refers to known PFAS of known molecular weight from the sulphonic acid series, ester series and carbonic acid series. The targeted PFAS are detected by using Liquid Chromatography with tandem mass spectrometry (LC-MS-MS).
Non-targeted fluoroalkyl substance: The term “non-targeted fluoroalkyl substance” also known as “non-targeted PFAS” refers to the PFAS having unknown structures, which can be detected by using Quadrupole Time-of-Flight (QToF) mass spectrometer.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
Fluoropolymer is a fluorocarbon-based polymer with multiple carbon-fluorine bonds. It is characterized by having a high resistance to solvents, acids, and bases. The best known fluoropolymer is polytetrafluoroethylene (PTFE). The fluoropolymers are not susceptible as hydrocarbons to the van der Waals force, which contributes to their non-stick and friction reducing properties. These fluoropolymers are stable due to the multiple carbon-fluorine bonds present in the chemical compound. Fluoropolymers are mechanically characterized as thermosets or thermoplastics. Some of the examples of the fluoropolymers are polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTFE), perfluoroalkoxy polymer (PFA), fluorinated ethylene-propylene (FEP), polyethylenetetrafluoroethylene (ETFE), polyethylenechlorotrifluoroethylene (ECTFE), perfluorinated elastomer [perfluoroelastomer] (FFPM/FFKM), fluoroelastomer [vinylidene fluoride based copolymers] (FPM/FKM), fluoroelastomer [tetrafluoroethylene-propylene] (FEPM), perfluoropolyether (PFPE), perfluorosulfonic acid (PFSA) and the like.
The conventional methods known for the removal of the fluoroalkyl substances (PFAS) from effluent water are the use of activated carbon, reverse osmosis membranes, and the like. However, these methods are not effective and efficient for the removal of targeted and non-targeted PFAS from fluoropolymer latex.
Therefore, there is felt a need for developing a process for reducing the fluoroalkyl substances from the fluoropolymer latex that mitigates the drawbacks mentioned herein above or at least provide a useful alternative.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows.
An object of the present disclosure is to ameliorate one or more problems of the background or to at least provide a useful alternative.
Another object of the present disclosure is to provide a process for reducing the fluoroalkyl substances from a fluoropolymer latex.
Still another object of the present disclosure is to provide a process for reducing the fluoroalkyl substances from a fluoropolymer latex by using at least one ion exchange resin.
Yet another object of the present disclosure is to provide an easy, effective and efficient process for reducing the fluoroalkyl substances from a fluoropolymer latex.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
The present disclosure relates to a process for reducing the fluoroalkyl substances from a fluoropolymer latex. The fluoropolymer latex having a predetermined amount of fluoroalkyl substances is treated with a predetermined amount of at least one ion exchange resin, the treatment being carried out at a predetermined temperature for a predetermined time period to separately obtain a treated fluoropolymer latex having reduced amount of the fluoroalkyl substances, and the ion exchange resin having adsorbed thereon the fluoroalkyl substances.
In accordance with the embodiments of the present disclosure, the predetermined amount of the at least one ion exchange resin is in the range of 1 mass% to 15 mass% with respect to the total amount of the fluoropolymer latex.
In accordance with the embodiments of the present disclosure, the ion exchange resin is selected from the group consisting of

Formula-I
wherein the R1 and R2 are same or different with maximum one carbon atom; wherein the Formula-I is a macroporous cross-linked polystyrene co-polymer resin functionalized with a tertiary amine;
and

Formula-II
wherein the R1, R2, and R3 are same or different with maximum two carbon atoms; and X is a halogen selected from Cl, F, Br and I; wherein the Formula-II is a macroporous cross-linked polystyrene co-polymer resin functionalized with a quaternary amine.
In accordance with the embodiments of the present disclosure, the fluoroalkyl substances are selected from targeted fluoroalkyl substances and non-targeted fluoroalkyl substances.
In accordance with the embodiments of the present disclosure, wherein the fluoroalkyl substances are targeted fluoroalkyl substances, the predetermined amount of the fluoroalkyl substances is in the range of 10 ppb to 15 ppb with respect to the amount of the fluoropolymer latex.
In accordance with the embodiments of the present disclosure, wherein the fluoroalkyl substances are the targeted fluoroalkyl substances, the reduced amount of the fluoroalkyl substances in the treated fluoropolymer latex is in the range of 2 ppb to 3 ppb with respect to the amount of the treated fluoropolymer latex.
In accordance with the embodiments of the present disclosure, wherein the fluoroalkyl substances are the non-targeted fluoroalkyl substances, the predetermined amount of the fluoroalkyl substances is in the range of 2000 ppb to 16000 ppb with respect to the amount of the fluoropolymer latex.
In accordance with the embodiments of the present disclosure, wherein the fluoroalkyl substances are the non-targeted fluoroalkyl substance, the reduced amount of the fluoroalkyl substances in the treated fluoropolymer latex is in the range of 200 ppb to 1000 ppb with respect to the total amount of the treated fluoropolymer latex.
In accordance with the embodiments of the present disclosure, the predetermined temperature is in the range of 20 oC to 50 oC.
In accordance with another embodiment of the present disclosure, the predetermined temperature is in the range of 25 oC to 40 oC.
In accordance with the embodiments of the present disclosure, the predetermined time period is in the range of 12 hours to 36 hours.
In accordance with another embodiment of the present disclosure, the predetermined time period is in the range of 20 hours to 30 hours.
In accordance with the embodiments of the present disclosure, the treatment is carried out at a stirring speed in the range of 20 rpm to 100 rpm.
In accordance with another embodiment of the present disclosure, the treatment is carried out at a stirring speed in the range of 40 rpm to 70 rpm.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
The present disclosure will now be described with the help of the accompanying drawing, in which:
Fig. 1 illustrates a flow diagram for reducing the amount of fluoroalkyl substances from the fluoropolymer latex by using a stirring method in accordance with the present disclosure; and
Fig. 2 illustrates a flow diagram for reducing the amount of fluoroalkyl substances from the fluoropolymer latex by using a column method in accordance with the present disclosure.
DETAILED DESCRIPTION
The present disclosure relates to a process for reducing the fluoroalkyl substances from a fluoropolymer latex.
Embodiments, of the present disclosure, will now be described with reference to the accompanying drawing.
Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms "a,” "an," and "the" may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms "comprises," "comprising," “including,” and “having,” are open-ended transitional phrases and therefore specify the presence of stated features, integers, steps, operations, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The particular order of steps disclosed in the method and process of the present disclosure is not to be construed as necessarily requiring their performance as described or illustrated. It is also to be understood that additional or alternative steps may be employed.
As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed elements.
The terms first, second, third, etc., should not be construed to limit the scope of the present disclosure as the aforementioned terms may be only used to distinguish one element, component, region, layer or section from another component, region, layer or section. Terms such as first, second, third etc., when used herein do not imply a specific sequence or order unless clearly suggested by the present disclosure.
Fluoropolymer is a fluorocarbon-based polymer with multiple carbon-fluorine bonds. It is characterized by having a high resistance to solvents, acids, and bases. The best known fluoropolymer is polytetrafluoroethylene (PTFE). The fluoropolymers are not susceptible as hydrocarbons to the van der Waals force, which contributes to their non-stick and friction reducing properties. These fluoropolymers are stable due to the multiple carbon-fluorine bonds present in the chemical compound. Fluoropolymers are mechanically characterized as thermosets or thermoplastics. Some of the examples of the fluoropolymers are polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTFE), perfluoroalkoxy polymer (PFA), fluorinated ethylene-propylene (FEP), polyethylenetetrafluoroethylene (ETFE), polyethylenechlorotrifluoroethylene (ECTFE), perfluorinated elastomer [perfluoroelastomer] (FFPM/FFKM), fluoroelastomer [vinylidene fluoride based copolymers] (FPM/FKM), fluoroelastomer [tetrafluoroethylene-propylene] (FEPM), perfluoropolyether (PFPE), perfluorosulfonic acid (PFSA) and the like.
The conventional methods known for the removal of fluoroalkyl substances (PFAS) from effluent water are the use of activated carbon, reverse osmosis membranes, and the like. However, these methods are not effective and efficient for the removal of targeted and non-targeted PFAS from fluoropolymer latex.
The present disclosure provides a process for reducing the fluoroalkyl substances from the fluoropolymer latex.
In accordance with the present disclosure, the term ‘reducing’ refers to reducing the amount of fluoroalkyl substances from fluoropolymer latex. The process for reducing the fluoroalkyl substances from the fluoropolymer latex is described.
The fluoropolymer latex having a predetermined amount of the fluoroalkyl substances is treated with a predetermined amount of at least one ion exchange resin. The treatment being carried out at a predetermined temperature for a predetermined time period to separately obtain a treated fluoropolymer latex having reduced amount of the fluoroalkyl substances, and the ion exchange resin having adsorbed thereon the fluoroalkyl substances.
In accordance with the present disclosure, the fluoropolymers are selected from the group consisting of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTFE), perfluoroalkoxy polymer (PFA), fluorinated ethylene-propylene (FEP), polyethylenetetrafluoroethylene (ETFE), polyethylenechlorotrifluoroethylene (ECTFE), perfluorinated elastomer [perfluoroelastomer] (FFPM/FFKM), fluoroelastomer [vinylidene fluoride based copolymers] (FPM/FKM), fluoroelastomer [tetrafluoroethylene-propylene] (FEPM), perfluoropolyether (PFPE), and perfluorosulfonic acid (PFSA). The monomers of these fluoropolymers are combined with the monomers such as hexafluoropropylene (HFP), perfluoropropylvinyl ether (PPVE), poly (methyl vinyl ether) (PMVE), chlorotrifluoroethylene (CTFE), expanded polytetrafluoroethylene (ePTFE), and perfluorobutylethylene (PFBE) to form a copolymer. The fluoropolymer latex is prepared from a surfactant selected from the group consisting a fluorinated surfactant and a non-fluorinated surfactant.
In accordance with the embodiments of the present disclosure, the fluoroalkyl substances are selected from targeted fluoroalkyl substances and non-targeted fluoroalkyl substances.
In accordance with the present disclosure, the fluoroalkyl substances are perfluoroalkyl substances and polyfluoroalkyl substances (PFAS). The fluoroalkyl substances can be one fluoroalkyl substance or a heterogenous mixture of the fluoroalkyl substances.
In accordance with the present disclosure, the ion exchange resin having adsorbed the fluoroalkyl substances are regenerated.
In accordance with the embodiments of the present disclosure, the predetermined amount of the at least one ion exchange resin is in the range of 1 mass% to 15 mass% with respect to the total amount of the fluoropolymer latex. In an exemplary embodiment, the predetermined amount of the at least one ion exchange resin is 3.8 mass% with respect to the total amount of the fluoropolymer latex. In another exemplary embodiment, the predetermined amount of the at least one ion exchange resin is 13.3 mass% with respect to the total amount of the fluoropolymer latex.
In accordance with the embodiments of the present disclosure, the ion exchange resin is selected from the group consisting of

Formula-I
wherein R1 and R2 are same or different with maximum one carbon atom, wherein the Formula-I is a macroporous cross-linked polystyrene co-polymer resin functionalized with a tertiary amine;
and

Formula-II
wherein R1, R2 and R3 are same or different with maximum of two carbon atoms; and X is a halogen selected from Cl, F, Br and I; wherein the Formula-II is a macroporous cross-linked polystyrene co-polymer resin functionalized with a quaternary amine. In an exemplary embodiment, the ion exchange resin is the ion exchange resin of Formula-I. In another exemplary embodiment, the ion exchange resin is the ion exchange resin of Formula-II.
In accordance with the embodiments of the present disclosure, wherein the fluoroalkyl substances are targeted fluoroalkyl substances, the predetermined amount of the fluoroalkyl substances is in the range of 10 ppb to 15 ppb with respect to the amount of the fluoropolymer latex.
In accordance with the embodiments of the present disclosure, wherein the fluoroalkyl substances are the targeted fluoroalkyl substances, the reduced amount of the fluoroalkyl substances in the treated fluoropolymer latex is in the range of 2 ppb to 3 ppb with respect to the amount of the treated fluoropolymer latex.
In accordance with the embodiments of the present disclosure, wherein the fluoroalkyl substances are the non-targeted fluoroalkyl substances, the predetermined amount of the fluoroalkyl substances is in the range of 2000 ppb to 16000 ppb with respect to the amount of the fluoropolymer latex. In an exemplary embodiment, wherein the fluoroalkyl substances are the non-targeted fluoroalkyl substances, the predetermined amount of the fluoroalkyl substances is 8700 ppb with respect to the amount of the fluoropolymer latex. In another exemplary embodiment, wherein the fluoroalkyl substances are the non-targeted fluoroalkyl substance, the predetermined amount of the fluoroalkyl substances is 15600 ppb with respect to the amount of the fluoropolymer latex.
In accordance with the embodiments of the present disclosure, wherein the fluoroalkyl substances are the non-targeted fluoroalkyl substance, the reduced amount of the fluoroalkyl substances in the treated fluoropolymer latex is in the range of 200 ppb to 1000 ppb with respect to the amount of the treated fluoropolymer latex. In an exemplary embodiment, wherein the fluoroalkyl substances are the non-targeted fluoroalkyl substance, the reduced amount of the fluoroalkyl substances in the treated fluoropolymer latex is 560 ppb with respect to the amount of the treated fluoropolymer latex. In another exemplary embodiment, wherein the fluoroalkyl substances are the non-targeted fluoroalkyl substance, the reduced amount of the fluoroalkyl substances in the treated fluoropolymer latex is 975 ppb with respect to the amount of the treated fluoropolymer latex.
In accordance with the embodiments of the present disclosure, the predetermined temperature is in the range of 20 oC to 50 oC. In accordance with another embodiment of the present disclosure, the predetermined temperature is in the range of 25 oC to 40 oC. In an exemplary embodiment, the predetermined temperature is 27 oC (ambient temperature).
In accordance with the embodiments of the present disclosure, the initial pH of the fluoropolymer latex is in the range of 2 to 4. However, after resin treatment, the pH of the treated fluoropolymer latex is in the range of 2.8 to 10.
In accordance with the embodiments of the present disclosure, the predetermined time period is in the range of 12 hours to 36 hours. In accordance with another embodiment of the present disclosure, the predetermined time period is in the range of 20 hours to 30 hours. In the exemplary embodiments, the predetermined time period is 24 hours.
In accordance with the embodiments of the present disclosure, the treatment is carried out at a stirring speed in the range of 20 rpm to 100 rpm. In accordance with another embodiment of the present disclosure, the treatment is carried out at a stirring speed in the range of 40 rpm to 70 rpm. In an exemplary embodiment, the treatment is carried out at a stirring speed of 65 rpm.
The process of the present disclosure is performed either by using a reactor and a stirrer, or a column.
In the process, as shown in Fig. 1, wherein the reactor and stirrer are used, the fluoropolymer latex is treated with the at least one ion exchange resin in a reactor under stirring at 27 oC for 12-36 hours to obtain the ion exchange resin having adsorbed the fluoroalkyl substances and the fluoropolymer latex having reduced amount of the fluoroalkyl substances. The ion exchange resin after treatment are separated by filtration.
In the process as shown in Fig. 2, wherein the column is used, the fluoropolymer latex is passed through a column filled with at least one ion exchange resin at 27 oC to obtain the ion exchange resin having adsorbed the fluoroalkyl substances and the fluoropolymer latex having the reduced amount of the fluoroalkyl substances.
The resin bed consists of a packed column of ion exchange resin particles, can be typically made of a polymeric material functionalized with specific functional groups that selectively adsorb or exchange target ions or molecules. The resin bed can be usually housed in a cylindrical column with an inlet port and an outlet port for sample injection and elution, respectively.
In accordance with the present disclosure, the fluoropolymer latex having predetermined amount of PFAS can be passed through the single or multiple resin beds. The target ions or molecules can be selectively adsorbed by the resin particles, while other unwanted species are allowed to pass through. The degree of separation depends on the specific functional group of the resin and the chemical properties of the sample components.
In accordance with the present disclosure, the treated fluoropolymer latex can have significantly reduced amount of the fluoroalkyl substances, making the fluoropolymer safer and environment friendly.
In accordance with the present disclosure, the treated fluoroalkyl substances (PFAS) concentration in the treated fluoropolymer latex is measured using analytical techniques such as liquid chromatography-mass spectrometry (LC-MS/MS) for targeted PFAS and Quadrupole Time of Flight Mass Spectrometer (QToF MS) for non-targeted semi-quantitative fluoroalkyl substance.
The use of the specific ion exchange resins resulted in a significant reduction in the amount of the fluoroalkyl substances, both for the targeted and non-targeted fluoroalkyl substances contaminants.
The process of the present disclosure for reducing the amount of the fluoroalkyl substances from the fluoropolymer latex is highly effective, while having minimal impact on the overall properties of the fluoropolymer latex.
In accordance with the present disclosure, the process is reduced to practice through a series of experiments and provide evidence of its effectiveness in reducing the amounts of targeted and non-targeted fluoroalkyl substances from complex fluoropolymer latex.
The process of the present disclosure can reduce the environmental footprint and contribute to safer and more sustainable fluoropolymers. The process of the present disclosure aligns with regulatory trends and consumer preferences for products that are free from harmful chemicals (PFAS).
The process of the present disclosure can be scaled up depending on the volume of the fluoropolymer latex needing treatment, making it suitable for small-scale applications as well as large-scale industrial processes.
The process of the present disclosure is remarkably straightforward, highly efficient, and seamlessly integrates into the existing hardware setups with minimal adjustments. It offers a remarkable level of simplicity without necessitating any significant modifications to the current infrastructure. Moreover, it consistently delivers reliable results, ensuring a dependable outcome every time.
The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment but are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
The present disclosure is further illustrated herein below with the help of the following experiments. The experiments used herein are intended merely to facilitate an understanding of the ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the experiments should not be construed as limiting the scope of embodiments herein.
EXPERIMENTAL DETAILS
a) Process for reducing the fluoroalkyl substances from a homo-fluoropolymer latex in accordance with the present disclosure
Example 1
500 ml of fluoropolymer latex was charged into a reactor. Thereafter, 19 ml of ion exchange resin of Formula-I was added to the reactor, and stirred at 27 oC (room temperature) for 24 hours at the speed of the agitator at 65 rpm and the agitator was then stopped to terminate the batch reaction. The resin from the resultant treated fluoropolymer latex was separated by filtration and the filtrate fluoropolymer sample so obtained was analyzed through LC-MS/MS for targeted PFAS, and the non-targeted PFAS were analyzed through QToF. The initial total non-targeted PFAS was 8900 ppb and after resin treatment the non-targeted PFAS was 975 ppb. The initial total targeted PFAS was 10-15 ppb and after resin treatment the targeted PFAS was <3 ppb.
Example 2
500 ml of fluoropolymer was charged into a reactor. Thereafter, 28.5 ml of ion exchange resin of Formula-II was added and stirred at 27 oC (room temperature) for 24 hours at the speed of the agitator at 65 rpm and the agitator was then stopped to terminate the batch reaction. The resin from the resultant treated fluoropolymer latex was separated by filtration and the filtrate fluoropolymer sample so obtained was analyzed through LC-MS/MS for targeted PFAS and the non-targeted PFAS was analyzed through QToF. The initial total non-targeted PFAS was 9050 ppb and after resin treatment the non-targeted PFAS was 650 ppb. The initial total targeted PFAS was 10-15 ppb and after resin treatment targeted PFAS was <3 ppb.
Example 3
500 ml of fluoropolymer latex was charged into a reactor. Thereafter, 38.0 ml of ion exchange resin of Formula-I was added, and stirred at 27 oC (room temperature) for 24 hours at the speed of the agitator at 65 rpm and the agitator was then stopped to terminate the batch reaction. The resin from the resultant treated fluoropolymer latex was separated by filtration and the filtrate fluoropolymer sample so obtained was analyzed through LC-MS/MS for targeted PFAS, and the non-targeted PFAS were analyzed through QToF. The initial total non-targeted PFAS was 8700 ppb and after resin treatment the non-targeted PFAS was 560 ppb. The initial total targeted PFAS was 10-15 ppb and after resin treatment targeted PFAS was <3.
Example 4
500 ml of fluoropolymer latex was charged into a reactor. Thereafter, 47.5 ml of ion exchange resin of Formula-II was added, and stirred at 27 oC (room temperature) for 24 hours at the speed of the agitator at 65 rpm and the agitator was then stopped to terminate the batch reaction. The resin from the resultant treated fluoropolymer latex was separated by filtration and the filtrate fluoropolymer sample so obtained was analyzed through LC-MS/MS for targeted PFAS, and the non-targeted PFAS were analyzed through QToF. The initial total non-targeted PFAS was 8634 ppb and after resin treatment the non-targeted PFAS was 440 ppb. The initial total targeted PFAS was 10-15 ppb and after resin treatment the targeted PFAS was <3 ppb.
Example 5
500 ml of fluoropolymer was charged into a reactor. Thereafter, 57.0 ml of ion exchange resin of Formula-I was added, and stirred at 27 oC (room temperature) for 24 hours at the speed of the agitator at 65 rpm and the agitator was then stopped to terminate the batch reaction. The resin from the resultant treated fluoropolymer latex was separated from by filtration and the filtrate fluoropolymer sample so obtained was analyzed through LC-MS/MS for targeted PFAS and the non-targeted PFAS was analyzed through QToF. The initial total non-targeted PFAS was 8930 ppb and after resin treatment the non-targeted PFAS was 335 ppb. The initial total targeted PFAS was 10-15 ppb and after resin treatment, the targeted PFAS was <2 ppb.
Example 6
500 ml of fluoropolymer latex was charged into a reactor. Thereafter, 66.5 ml of ion exchange resin of Formula-II was added, and stirred at 27 oC (room temperature) for 24 hours at the speed of the agitator at 65 rpm and the agitator was then stopped to terminate the batch reaction. The resin from the treated resultant fluoropolymer latex was separated by filtration and the filtrate fluoropolymer sample so obtained was analyzed through LC-MS/MS for targeted PFAS, and the non-targeted PFAS were analyzed through QToF. The initial total non-targeted PFAS was 8814 ppb and after resin treatment the non-targeted was 200 ppb. The initial total targeted PFAS was 10-15 ppb and after resin treatment the targeted PFAS was <2 ppb.
b) Process for reducing the fluoroalkyl substances from a co-fluoropolymer latex in accordance with the present disclosure
Example 7
500 ml of fluoropolymer latex was charged into a reactor. Thereafter, 16 ml of ion exchange resin of Formula-I was added, and stirred at 27 oC (room temperature) for 24 hours at the speed of the agitator at 65 rpm and the agitator was then stopped to terminate the batch reaction. The resin from the resultant treated fluoropolymer latex was separated by filtration and the filtrate fluoropolymer sample so obtained was analyzed through LC-MS/MS for targeted PFAS, and the non-targeted PFAS were analyzed through QToF. The initial total non-targeted PFAS was 15600 ppb and after resin treatment the non-targeted PFAS was 963 ppb. The initial total targeted PFAS was 10-15 ppb and after resin treatment the targeted PFAS was <3 ppb.
Example 8
500 ml of fluoropolymer latex was charged into a reactor. Thereafter, 24 ml of ion exchange resin of Formula-II was added to the reactor, and stirred at 27 oC (room temperature) for 24 hours at the speed of the agitator at 65 rpm and the agitator was then stopped to terminate the batch reaction. The resin from the resultant treated fluoropolymer latex was separated by filtration and the filtrate fluoropolymer sample so obtained was analyzed through LC-MS/MS for the targeted PFAS, and the non-targeted PFAS was analyzed through QToF. The initial total non-targeted PFAS was 14560 ppb and after resin treatment the non-targeted PFAS was 560 ppb. The initial total targeted PFAS was 10-15 ppb and after resin treatment targeted PFAS was <3 ppb.
Example 9
500 ml of fluoropolymer latex was charged into a reactor. Thereafter, 32 ml of ion exchange resin of Formula-I was added to the reactor, and stirred at 27 oC (room temperature) for 24 hours at the speed of the agitator at 65 rpm and the agitator was then stopped to terminate the batch reaction. The resin from the resultant treated fluoropolymer latex was separated by filtration and the filtrate fluoropolymer sample so obtained was analyzed through LC-MS/MS for targeted PFAS and the non-targeted PFAS were analyzed through QToF. The initial total non-targeted PFAS was 15150 ppb and after resin treatment the non-targeted PFAS was 480 ppb. The initial total targeted PFAS was 10-15 ppb and after resin treatment targeted PFAS was <3 ppb.
Example 10
500 ml of fluoropolymer latex was charged into a reactor. Thereafter, 40 ml of ion exchange resin of Formula-II was added to the reactor, and stirred at 27 oC (room temperature) for 24 hours at the speed of the agitator at 65 rpm and the agitator was then stopped to terminate the batch reaction. The resin from the resultant treated fluoropolymer latex was separated by filtration and the filtrate fluoropolymer sample so obtained was analyzed through LC-MS/MS for targeted PFAS, and the non-targeted PFAS were analyzed through QToF. The initial total non-targeted PFAS was 14490 ppb and after resin treatment the non-targeted was 240 ppb. The initial total targeted PFAS was 10-15 ppb and after resin treatment the targeted PFAS was <3 ppb.
Example 11
500 ml of fluoropolymer was charged into a reactor. Thereafter, 48 ml of ion exchange resin of Formula-I was added to the reactor, and stirred at 27 oC (room temperature) for 24 hours at the speed of the agitator at 65 rpm and the agitator was then stopped to terminate the batch reaction. The resin from the resultant treated fluoropolymer latex was separated by filtration and the filtrate fluoropolymer sample so obtained was analyzed through LC-MS/MS for the targeted PFAS, and the non-targeted PFAS was analyzed through QToF. The initial total non-targeted PFAS was 15250 ppb and after resin treatment the non-targeted PFAS was 325 ppb. The initial total targeted PFAS was 10-15 ppb and after resin treatment the targeted PFAS was <3 ppb.
Example 12
500 ml of fluoropolymer latex was charged into a reactor. Thereafter, 56 ml of ion exchange resin of Formula-II was added to the reactor, and stirred at 27 oC (room temperature) for 24 hours at the speed of the agitator at 65 rpm and the agitator was then stopped to terminate the batch reaction. The resin from the resultant treated fluoropolymer latex was separated by filtration and the filtrate fluoropolymer sample so obtained was analyzed through LC-MS/MS for targeted PFAS, and the non-targeted PFAS was analyzed through QToF. The initial total non-targeted PFAS was 14890 ppb and after resin treatment the non-targeted PFAS was 285 ppb. The initial total targeted PFAS was 10-15 ppb and after resin treatment targeted PFAS was <3 ppb.
Consolidated PFAS reduction results, when the fluoropolymer was treated with ion exchange resin at 27 oC, under stirring 65 rpm for 24 hours are represented in Table 1.
Table 1: Consolidated PFAS reduction results
Ex. No. Resin Dosages %(v/v) Grade of the fluoropolymer Operational condition Initial total PFAS (ppb) After resin treatment
Total PFAS (ppb)
Temp°C Time(h) Speed (rpm) Non-targeted PFAS Targeted PFAS Non-targeted PFAS Targeted PFAS
1 3.8 Homopolymer 27 65 8900 10-15 975 <3
2 5.7 Homopolymer 27 24 65 9050 10-15 650 <3
3 7.6 Homopolymer 27 24 65 8700 10-15 560 <3
4 9.5 Homopolymer 27 24 65 8634 10-15 440 <3
5 11.4 Homopolymer 27 24 65 8930 10-15 335 <2
6 13.3 Homopolymer 27 24 65 8814 10-15 200 <2
7 3.2 Co-polymer 27 24 65 15600 10-15 963 <3
8 4.8 Co-polymer 27 24 65 14560 10-15 560 <3
9 6.4 Co-polymer 27 24 65 15150 10-15 480 <3
10 8 Co-polymer 27 24 65 14490 10-15 240 <3
11 9.6 Co-polymer 27 24 65 15250 10-15 325 <3
12 11.2 Co-polymer 27 24 65 14890 10-15 285 <3
Table 2 provides the amounts of specific non-targeted PFAS initially present in the fluoropolymer latex and after resin treatment in the fluoropolymer latex.
Table 2: Amounts of specific non-targeted PFAS initially present in the fluoropolymer latex and after resin treatment in the latex.
Ex. No. Total non-targeted PFAS (ppb) CF3(CF2)nCHFSO3H
(ppb) CF3(CF2)nCHFCOOH
(ppb) CF3(CF2)nCHFCOOC2H5
(ppb)
Initial After treatment Initial After treatment Initial After treatment Initial After treatment
1 8900 975 1100 54 4468 495 3176 290
2 9050 650 1256 38 4570 348 3004 205
3 8700 560 1144 26 4480 242 2753 185
4 8634 440 1056 18 4388 206 2646 154
5 8930 335 1350 13 4268 183 2712 117
6 8814 200 1134 5 4345 86 2678 66
7 15600 963 1435 35 8975 468 4547 393
8 14560 560 1558 42 9016 314 4344 175
9 15150 480 1510 21 8688 249 4460 152
10 14490 240 1360 4 8330 81 4310 115
11 15250 325 1575 21 8780 178 4499 120
12 14890 285 1373 9 8358 101 4305 129

It was observed that the amount of the fluoroalkyl substances in the fluoropolymer latex was reduced efficiently by using the ion exchange resin of examples 1-12.
Example 13: Process for reducing the fluoroalkyl substances from a fluoropolymer latex (comparative example)
500 ml of fluoropolymer latex was charged into a reactor. Thereafter, 19 ml of polystyrene co-polymer strong base anion Quaternary Ammonium Ion exchange resin was added, and stirred at 27 oC (room temperature) for 24 hours at the speed of the agitator at 65 rpm and the agitator was then stopped to terminate the batch reaction. The resin from the resultant treated fluoropolymer latex was separated by filtration and the filtrate fluoropolymer sample so obtained was analyzed through LC-MS/MS for the targeted PFAS and the non-targeted PFAS was analyzed through QToF. The initial total non-targeted PFAS was 9034 ppb and after resin treatment the non-targeted PFAS was 3729 ppb. The initial total targeted PFAS was 10-15 ppb and after resin treatment targeted PFAS was <3 ppb.
Example 14: Process for reducing the fluoroalkyl substances from a fluoropolymer latex (comparative example)
500 ml of fluoropolymer latex was charged into a reactor. Thereafter, 28.5 ml of polystyrene co-polymer weak base tertiary amine ion exchange resin was added to the reactor, and stirred at 27 oC (room temperature) for 24 hours at the speed of the agitator at 65 rpm and the agitator was then stopped to terminate the batch reaction. The resin from the resultant treated fluoropolymer latex was separated by filtration and the filtrate fluoropolymer sample so obtained was analyzed through LC-MS/MS for the targeted PFAS, and the non-targeted PFAS was analyzed through QToF. The initial total non-targeted PFAS was 9034 ppb and after resin treatment the non-targeted PFAS was 4200 ppb. The initial total targeted PFAS was 10-15 ppb and after resin treatment the targeted PFAS is <3 ppb.
Example 15: Process for reducing the fluoroalkyl substances from a fluoropolymer latex (comparative example)
500 ml of fluoropolymer latex was charged into a reactor. Thereafter, 38.0 ml of styrene cross-linked with divinyl benzene strong base anion exchange resin was added to the reactor, and stirred at 27 oC (room temperature) for 24 hours at the speed of the agitator at 65 rpm and the agitator was then stopped to terminate the batch reaction. The resin from the resultant treated fluoropolymer latex was separated by filtration and the filtrate fluoropolymer sample so obtained was analyzed through LC-MS/MS for targeted PFAS and the non-targeted PFAS was analyzed through QToF. The initial total non-targeted PFAS was 9034 ppb and after resin treatment the non-targeted PFAS was 2196 ppb. The initial total targeted PFAS was 10-15 ppb and after resin treatment targeted PFAS was <3 ppb.
Example 16: Process for reducing the fluoroalkyl substances from a fluoropolymer latex (comparative example)
500 ml fluoropolymer latex was charged into a reactor. Thereafter, 47.5 ml of styrene cross-linked with divinyl benzene weak base anion exchange resin was added to the reactor, and stirred at 27 oC (room temperature) for 24 hours at the speed of the agitator at 65 rpm and the agitator was then stopped to terminate the batch reaction. The resin was separated from the fluoropolymer by filtration and the filtrate fluoropolymer sample so obtained was analyzed through LC-MS/MS for the targeted PFAS and the non-targeted PFAS was analyzed through QToF. The initial total non-targeted PFAS was 9034 ppb and after resin treatment the non-targeted PFAS was 4188 ppb. The initial total targeted PFAS was 10-15 ppb and after resin treatment targeted PFAS was <3 ppb.
Table 3 compiles the experimental conditions and the results of examples 13 to 16, carried out at 27 oC, under stirring at 65 rpm for 24 hours.
Table 3: Experimental conditions and outcomes of examples 13 to 16
Ex. No. Resin name Resin Dosages (%) Initial total PFAS (ppb) After resin treatment
PFAS (ppb)
Non-targeted PFAS Targeted PFAS Non-targeted PFAS Targeted PFAS
13 Polystyrene co-polymer strong base anion quaternary ammonium ion exchange resin 3.8 9034 10-15 3729 <3
14 Polystyrene co-polymer weak base tertiary amine ion exchange resin 5.7 9034 10-15 4200 <3
15 Styrene cross linked with divinyl benzene strong base anion exchange resin 7.6 9034 10-15 2196 <3
16 Styrene cross linked with divinyl benzene weak base anion exchange resin 9.5 9034 10-15 4188 <3

Examples 13 to 16 were used to reduce the amount of PFAS from the homopolymer fluoropolymer latex by using various types of resin but could not get the expected results.
The non-targeted PFAS was analysed by state of art instrument Q-ToF (Quadrupole Time of flight) High Mass resolution, Make Sciex Model: X500R, System: Sciex X500R QToF with SWATH data, Mobile Phase A: 20mM Ammonium Acetate in MilliQ water, Mobile Phase B: 20mM Ammonium Acetate in Methanol, Column: Phenomenex Gemini 3.0µm C18 110A LC column, 50mm X 3mm, Flow rate: 0.5 ml/min, and Run time: 20 minutes.
TECHNICAL ADVANCEMENTS
The present disclosure described hereinabove has several technical advantages including, but not limited to, the realization of: a process for reducing the fluoroalkyl substances from a fluoropolymer latex that-
• reduces the amounts of both the targeted and non-targeted fluoroalkyl substances (PFAS);
• is effective and efficient;
• supports development of safe and sustainable process of manufacturing of the fluoropolymers; and
• provides practical and cost-effective solution for the industries that rely on the fluoropolymers.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
The foregoing description of the specific embodiments so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.
Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary.
While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation. ,CLAIMS:WE CLAIM:
1. A process for reducing the fluoroalkyl substances from a fluoropolymer latex, said process comprising treating fluoropolymer latex having a predetermined amount of fluoroalkyl substances with a predetermined amount of at least one ion exchange resin,
said treatment being carried out at a predetermined temperature for a predetermined time period to separately obtain
• a treated fluoropolymer latex having reduced amount of said fluoroalkyl substances, and
• said ion exchange resin having adsorbed thereon said fluoroalkyl substances.
2. The process as claimed in claim 1, wherein said predetermined amount of said at least one ion exchange resin is in the range of 1 mass% to 15 mass% with respect to the total amount of the fluoropolymer latex.
3. The process as claimed in claim 1, wherein said ion exchange resin is selected from the group consisting of

Formula-I
wherein said R1 and R2 are same or different with maximum one carbon atom; wherein said Formula-I is a macroporous cross-linked polystyrene co-polymer resin functionalized with a tertiary amine;
and

Formula-II
wherein said R1, R2 and R3 are same or different with maximum two carbon atoms; and X is a halogen selected from Cl, F, Br and I; wherein said Formula-II is a macroporous cross-linked polystyrene co-polymer resin functionalized with a quaternary amine.
4. The process as claimed in claim 1, wherein said fluoroalkyl substances are selected from targeted fluoroalkyl substances and non-targeted fluoroalkyl substances.
5. The process as claimed in claim 1, wherein said fluoroalkyl substances are targeted fluoroalkyl substances, said predetermined amount of said fluoroalkyl substances is in the range of 10 ppb to 15 ppb with respect to the amount of said fluoropolymer latex.
6. The process as claimed in claim 1, wherein said fluoroalkyl substances are targeted fluoroalkyl substances, said reduced amount of said fluoroalkyl substances in the treated fluoropolymer latex is in the range of 2 ppb to 3 ppb with respect to the amount of said treated fluoropolymer latex.
7. The process as claimed in claim 1, wherein said fluoroalkyl substances are non-targeted fluoroalkyl substances, said predetermined amount of said fluoroalkyl substances is in the range of 2000 ppb to 16000 ppb with respect to the amount of said fluoropolymer latex.
8. The process as claimed in claim 1, wherein said fluoroalkyl substances are non-targeted fluoroalkyl substances, said reduced amount of said fluoroalkyl substances in the treated fluoropolymer latex is in the range of 200 ppb to 1000 ppb with respect to the amount of said treated fluoropolymer latex.
9. The process as claimed in claim 1, wherein said predetermined temperature is in the range of 20 oC to 50 oC.
10. The process as claimed in claim 1, wherein said predetermined temperature is in the range of 25 oC to 40 oC.
11. The process as claimed in claim 1, wherein said predetermined time period is in the range of 12 hours to 36 hours.
12. The process as claimed in claim 1, wherein said predetermined time period is in the range of 20 hours to 30 hours.
13. The process as claimed in claim 1, wherein said treatment is carried out at a stirring speed in the range of 20 rpm to 100 rpm.
14. The process as claimed in claim 1, wherein said treatment is carried out at a stirring speed in the range of 40 rpm to 70 rpm.

Dated this 02nd day of May, 2024

_______________________________
MOHAN RAJKUMAR DEWAN, IN/PA – 25
of R.K.DEWAN & CO.
Authorized Agent of Applicant

TO,
THE CONTROLLER OF PATENTS
THE PATENT OFFICE, NEW DELHI