Base-mediated deconstruction of epoxy resins

Abstract

The invention relates to a method for decomposing an epoxy-based polymer, comprising subjecting a cured epoxy resin to a chemical operation involving a mixture of at least one organic solvent and a base. In particular, the epoxy-based polymer is an amine cured epoxy resin, and the base is a nucleophilic base. The present invention can recover the components contained in the cured epoxy resin at high yield, especially even in the absence of any metal catalyst.

Description

Technical Field

[0001] The present invention relates to a method for disassembling epoxy-based polymers, the method comprising subjecting a cured epoxy resin to a chemical operation involving a mixture of at least one organic solvent and a base. Specifically, the epoxy-based polymer is an amine-cured epoxy resin containing a bisphenol component. The present invention allows the recovery of components contained in the cured epoxy resin in high yield, especially even in the absence of any catalyst, metal or other substance. Background Art

[0002] Large amounts of used plastics and plastic-containing materials are discharged into nature, leading to a serious environmental crisis that has a significant impact on ecosystems around the world. The need to implement a circular economy for plastics and plastic-containing composites, reduce resource consumption and limit waste entering the environment has become apparent.

[0003] Chemical recycling enables the breakdown of otherwise spent polymers into their original monomers or associated base chemicals, which can then re-enter the production chain to produce virgin-grade polymer materials. Achieving this circular economy therefore has the opportunity to transform the ever-accumulating plastic waste into a valuable resource. Catalytic hydrogenation of carbonyl moieties in thermoset polyurethanes, to recover aniline and polyols, has recently been reported as a strategy to achieve this principle. In contrast, epoxy resins lack reactive carbonyl moieties, which makes selective breaking of their chemical bonds more challenging. Therefore, without viable recycling technologies, the value and potential of epoxy resins in fiber-reinforced epoxy composites will disappear with unsustainable consequences. Fiber-reinforced epoxy composites are lightweight, durable materials that typically consist of glass or carbon fibers embedded in an epoxy-based polymer matrix and are essential for the construction of motor vehicles, ships, aircraft and wind turbine blades. In 2021, wind turbine producer Siemens Gamesa commercialized turbine blades based on a resin system that allows the fibers to be separated from the resin using acidic conditions. While this approach is ingenious, the reuse of the recovered epoxy resin fraction is limited to uses such as filling material, meaning that a circular solution has not yet been achieved.

[0004] As society moves toward reducing or eliminating landfill waste, there is a clear need in the art for improved methods of deconstructing epoxy resins by chemical processes, particularly those that allow for recovery and recycling of the base components. Summary of the invention

[0005] The present invention relates to a method for base-mediated decomposition of epoxy-based polymers (EPBs) by chemical manipulations involving an organic solvent or mixture thereof and a suitable base, thereby allowing the recycling of EBP components, which would otherwise be mostly deposited in landfills or incinerated for energy recovery, thereby causing air pollution. The use of metal catalysts, particularly catalysts based on expensive transition metals such as ruthenium, palladium, rhodium, platinum and gold, is highly undesirable in industrial-scale applications because it often makes otherwise useful reactions unfeasible from a financial perspective. In addition, many of these catalytic processes require the exclusion of moisture and / or oxygen, which makes scale-up more challenging and hinders rapid process development for commercial applications. Therefore, one aspect of the present invention is to provide a method for base-mediated decomposition of epoxy-based polymers that does not involve the use of any catalyst, metal catalyst or other substance.

[0006] One main aspect of the present invention is a method of deconvolution of an epoxy-based polymer (EBP), the method comprising providing the EBP, and further comprising the step of contacting the EBP with a solvent system comprising at least one organic solvent and a base to form a suspension.

[0007] In some embodiments, this aspect will provide a method of deconvoluting an epoxy-based polymer (EBP), the method comprising the steps of:

[0008] a. Provide EBP,

[0009] b. contacting the EBP with a solvent system comprising at least one aprotic non-polar organic solvent and an oxygen-containing base to form a suspension, and

[0010] c. heating the suspension to a temperature of at least 130° C. for at least 2 hours, thereby releasing the monomers of EBP into the suspension,

[0011] The base is added in an amount equivalent to 20% to 100% by weight of the EBP, and the method does not include or use a catalyst.

[0012] Preferably, steps a, b, and c of the method are performed sequentially in a prescribed order.

[0013] The EBP described in the present disclosure may comprise a chemical structural unit of formula (III-a):

[0014]

[0015] in,

[0016] X1 is selected from H, R or -C(=O)R, wherein R can be C 1-6Alkyl, C 1-6 Heteroalkyl, C 1-6 Alkoxy, C 1-6 Allyl, C 1-6 Heteroallyl, C 4-8 Cycloalkyl, C 4-8 Heterocycloalkyl, C 4-8 Aryl and C 4-8 Heteroaryl, each of which may be optionally substituted with one or more of -OH, -NH2, -L, -CL3, -OCH3, wherein L is halogen;

[0017] X2 Selected from C 4-8 Cycloalkyl, C 4-8 Heterocycloalkyl, C 4-8 Aryl and C 4-8 Heteroaryl, each of which may be optionally substituted with one or more of -OH, -NH2, -Q, -CQ3, -OCH3, wherein each Q is independently hydrogen, halogen, methyl, phenyl or benzyl; and

[0018] n indicates that the structural unit is repeated, and may be an integer greater than 1. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 : An idealized schematic of the extended network in an epoxy-based polymer based on bisphenol A monomer. The schematic further highlights the specific bonds that are predicted to break when the epoxy-based polymer is deconvoluted into its basic components.

[0020] Figure 2 : Commercially available epoxy-based polymer Airstone deconvoluted in Examples 3 to 6 TM Image of 760E / 766H and its basic ingredients. Shown at the bottom is the epoxy monomer functionalized with a diglycidyl ether and shown at the top is the curing agent, also known as an epoxy hardener.

[0021] Figure 3 : Images of commercially available epoxy-based polymers and their basic components deconvoluted in Example 4. The bottom shows the epoxy monomer functionalized with diglycidyl ether and the top shows the curing agent, also known as epoxy hardener. a) UHU two-component glue; b) Roizefar epoxy resin; c) Sicomin SR infugreen 810 / SD8822.

[0022] Figure 4 : Filed Airstone measured by dynamic light scattering TMParticle size distribution in 760E / 766H powder (as described in Examples 1 and 3). Dynamic light scattering measurements showed that 10% of the particles were 32.8 μm or less in diameter, 50% were 134.1 μm or more in diameter, 50% were 134.1 μm or less in diameter, and 90% were 380.5 μm or less in diameter.

[0023] Figure 5 : The crude bisphenol A obtained by the method ii) of Example 5 1 H-NMR. The spectrum was measured in deuterated acetone (CD3)2CO and the peak for deuterated acetone was identified as being located at 2.05 ppm. The image shows all identified peaks but has been cropped for size considerations. The chemical shift range is from -0.5 to 7.0 with a major increment of 0.5. The signal count range is from -1000 to 15000 with a major increment of 1000. Further peak identifiers are given in Example 5.

[0024] Figure 6 : Pictures and reaction diagrams of the deconstruction process used in Example 6. 6A: Transparent casting Airstone immersed in acetic acid TM 760E / 766H. 6B: Decanted Airstone resin after two months in acetic acid showing that the resin had decomposed. 6C: Fragments recovered after decantation (left to right: chunks, chips and pellets). The pelletized sample was used 'as is' in Example 6. 6D: Schematic representation of the deconstruction reaction occurring in Example 6.

[0025] definition

[0026] As used herein, the term "polymer" refers to any of a class of substances composed of a plurality of linked repeating units (eg, repeating molecules).

[0027] As used herein, the term "EBP" refers to epoxy-based polymers. In this specification, these are polymers and / or crosslinked materials formed by the reaction of a substance containing epoxide functional groups with itself or other co-reactants. Epoxide functional groups are collectively referred to as epoxies.

[0028] The term "FREBP" as used herein refers to fibers reinforced with epoxy-based polymers. In the present description, these are composite materials comprising fibers embedded in an epoxy-based polymer matrix or other materials of different origin.

[0029] As used herein, the term "fiber" refers to any non-spherical material that can be advantageously cured with an epoxy-based polymer to improve the structural and / or durable integrity of the composite material compared to the cured polymer in the absence of the fiber material. Non-limiting examples of fiber materials within the meaning of the present disclosure include glass, cellulose, plastic, steel, metal, carbon, etc. Fiber and fiber can be used interchangeably herein.

[0030] The term "monomer" as used herein refers to a molecule or any class of compounds that can react with itself or other molecules to form an extended structure such as a polymer. Also as used herein, "monomer" may refer to a molecule that forms part of a repeating unit of a polymer. Preferably, monomers are primarily organic molecules containing suitable functional groups known to those skilled in the art. When referring to monomers in the context of the present invention, it is intended to refer to chemical entities that can be functionalized with epoxides for use in forming epoxy-based polymers. This includes, but is not limited to, bisphenols derivatized with electrophilic epoxides, in which case monomers will refer to non-derivatized bisphenols.

[0031] The term "crosslinking agent" as used herein refers to a molecule or any class of compounds that can react to connect two or more polymer chains, as well as a chemical structure that connects two or more polymer chains in a network. Also as mentioned herein, a "crosslinking agent" refers to a molecule that can react with an entity functionalized with an epoxide (e.g., a bisphenol derivative) to form an epoxy-based polymer.

[0032] As used herein, the term "deconvolution" generally refers to processing material ABCD into at least some of its basic components A, B, C, and D, thereby allowing their separate recovery. As used herein, "deconvolution" is used interchangeably with "deconstruction," "decomposition," "disconnection," and "degradation."

[0033] The term "catalyst" as used herein refers to any substance that increases the rate of one or more chemical reactions and does not itself undergo any permanent chemical changes. In addition, the term "catalyst" is a term well known to those skilled in the art.

[0034] Detailed Description

[0035] The present invention relates to a novel process for base-mediated decomposition of epoxy-based polymers (EPB) by chemical manipulations involving an organic solvent or a mixture thereof and a suitable base, thereby allowing the recycling of components of EBP which would otherwise largely be deposited in landfills or incinerated for energy recovery while generating undesirable air pollution.

[0036] One embodiment of the present disclosure is to provide a method for deconvoluting EBP by degrading chemical bonds in a polymer matrix. The inventors of the present invention unexpectedly discovered a composition mixture and temperature window in which EPB can be deconstructed very effectively, using only simple reagents to obtain high yields of basic components, such as bisphenols, more preferably bisphenol A. Even more surprisingly, the extremely high efficiency demonstrated herein can be achieved even without the need for a catalyst, such as without the need for a metal catalyst or a transition metal catalyst. In addition, the developed scheme has been shown to be tolerant to oxygen (air) and moisture. Without wishing to be bound by theory, the inventors of the present invention believe that the mismatch between bases and aprotic non-polar organic solvents is key to inducing base-mediated C-O bond cleavage, because poorly solvated ions are more reactive when targeted to the relevant bonds than when they are dissolved. Similarly, ions or polar intermediates formed during the conversion of epoxy resins to monomers are also equally affected by the non-polar medium, allowing challenging bond cleavage to occur under relatively mild conditions.

[0037] Thus, bisphenol monomers, such as the basic ingredients for making EBP, can be isolated directly from the reaction mixture, including prior to any derivatization with diglycidyl ethers. Thus, one embodiment of the presently disclosed method is one in which the method is a one-pot synthesis. The limitations and advantages of one-pot synthesis are well known to the chemical community and those skilled in the art. Thus, in one embodiment of the present disclosure, when practicing the disclosed method, the monomer released into the suspension is a bisphenol-based monomer, such as a bisphenol-A-based monomer, more preferably a non-derivatized bisphenol-A monomer.

[0038] One embodiment of the present disclosure is a method of deconvoluting an epoxy-based polymer (EBP), the method comprising providing the EBP, and further comprising the step of contacting the EBP with a solvent system comprising at least one organic solvent and a base to form a suspension.

[0039] In one embodiment of the methods disclosed herein, the methods are performed in the absence of a catalyst (eg, a metal catalyst), such as no metal catalyst is added at any point in the deconstruction of the epoxy-based polymer.

[0040] The scope of the present disclosure includes providing methods for deconvoluting EBPs, including those found in FREBPs, thereby allowing recovery of the EBP base components. Most preferably, the provided methods are used to deconvolute polymers obtained using bisphenol diglycidyl ethers as starting materials, exemplary bisphenol A diglycidyl ethers:

[0041]

[0042] In such an embodiment, one of these recycled ingredients is bisphenol A (BPA). BPA is derived from unsustainable petrochemicals and is a major building block for the production of polymers, with 6 million metric tons produced in 2017 alone. To prepare epoxy resins, BPA is functionalized with electrophilic epoxide moieties (e.g., diglycidyl ether). These monomeric or oligomeric epoxides can then be cured with exemplary (multifunctional) alkylamines to yield randomized 3D polymer networks that are interwoven by strong C-O and C-N σ bonds in different links, such as Figure 1 It is also within the scope of the present invention to extend this method to other epoxy-derived bisphenol compounds, such as bisphenol derivatives known to those of ordinary skill in the art.

[0043] In one embodiment of the methods disclosed herein, the EBP comprises a chemical structural unit of formula (II-a) or formula (II-a1):

[0044]

[0045] in,

[0046] X1 can be H, R or -C(=O)R, where R can be C 1-6 Alkyl, C 1-6 Heteroalkyl, C 1-6 Alkoxy, C 1-6 Allyl, C 1-6 Heteroallyl, C 4-8 Cycloalkyl, C 4-8 Heterocycloalkyl, C 4-8 Aryl and C 4-8 Heteroaryl, each of which may be optionally substituted with one or more of -OH, -NH2, -L, -CL3, -OCH3, wherein L is halogen;

[0047] X2 can be C 4-8 Cycloalkyl, C 4-8 Heterocycloalkyl, C 4-8 Aryl and C 4-8 Heteroaryl, each of which may be optionally substituted with one or more of -OH, -NH2, -Q, -CQ3, -OCH3, wherein each Q is independently hydrogen, halogen, methyl, phenyl or benzyl.

[0048] Preferably, in Formula II-a or Formula II-a1, X2 is C 4-8 Aryl, preferably aromatic C6 aryl such as benzene, is optionally substituted with one or more of -OH, -NH2, -Q, -CQ3, -OCH3, wherein each Q is independently hydrogen, halogen, methyl, phenyl or benzyl.

[0049] Thus, in one embodiment of the methods disclosed herein, the EBP comprises a chemical structural unit of formula (III-a):

[0050]

[0051] in,

[0052] X1 can be H, R or -C(=O)R, where R can be C 1-6 Alkyl, C 1-6 Heteroalkyl, C 1-6 Alkoxy, C 1-6 Allyl, C 1-6 Heteroallyl, C 4-8 Cycloalkyl, C 4-8 Heterocycloalkyl, C 4-8 Aryl and C 4-8 Heteroaryl, each of which may be optionally substituted with one or more of -OH, -NH2, -L, -CL3, -OCH3, wherein L is halogen; and

[0053] X2 can be C 4-8 Cycloalkyl, C 4-8 Heterocycloalkyl, C 4-8 Aryl and C 4-8 Heteroaryl, each of which may be optionally substituted with one or more of -OH, -NH2, -Q, -CQ3, -OCH3, wherein each Q is independently hydrogen, halogen, methyl, phenyl or benzyl; and

[0054] n indicates that the structural unit is repeated, and may be an integer greater than 1.

[0055] Preferably, in formula (III-a), X1 is H and X2 is C 4-8 Aryl, preferably aromatic C6 aryl such as benzene, is optionally substituted with one or more of -OH, -NH2, -Q, -CQ3, -OCH3, wherein each Q is independently hydrogen, halogen, methyl, phenyl or benzyl.

[0056] In one embodiment of the present disclosure, n defined in formula (III-a) is an integer of at least 1, such as at least 2, such as at least 5, such as at least 10, such as at least 50, such as at least 100, such as at least 200, such as at least 500, such as at least 1000, such as at least 10000.

[0057] In one embodiment of the present invention, n defined in formula (III-a) is an integer between 1 and 1000, such as 1 to 500, such as 1 to 400, such as 1 to 300, such as 1 to 200, such as 1 to 100.

[0058] In one embodiment of the present invention, n defined in formula (III-a) is an integer between 50 and 100, such as 100 to 200, such as 200 to 300, such as 300 to 500, such as 500 to 700, such as 700 to 1000.

[0059] In one embodiment of the methods disclosed herein, the EBP comprises a chemical structural unit of Formula II-a(i) or Formula II-a(i)-1:

[0060]

[0061] in,

[0062] X1 is selected from H, R or -C(=O)R,

[0063] X2 Selected from C 4-8 Cycloalkyl, C 4-8 Heterocycloalkyl, C 4-8 Aryl and C 4-8 Heteroaryl, each of which may be optionally substituted with one or more of -OH, -NH2, -Q, -CQ3, -OCH3, wherein each Q is independently hydrogen, halogen, methyl, phenyl or benzyl;

[0064] X3 can be selected from CR2, NZ, O and S,

[0065] Where R is selected from C 1-6 Alkyl, C 1-6 Heteroalkyl, C 1-6 Alkoxy, C 1-6 Allyl, C 1-6 Heteroallyl, C 4-8 Cycloalkyl, C 4-8 Heterocycloalkyl, C 4-8 Aryl and C 4-8 Heteroaryl, each of which may be optionally substituted with one or more of -OH, -NH2, -L, -CL3, -OCH3, wherein L is halogen;

[0066] wherein NZ represents an amine-based crosslinker and / or hardener selected from polyamide resins, poly(oxypropylene)diamine, 3-aminomethyl-3,5,5-trimethylcyclohexylamine, triethylenetetramine, tetraethylenepentamine, and amine-terminated trimethylolpropane tri[poly(propylene glycol)]ether (T-403).

[0067] Preferably, in formula (II-a(i)) or formula (II-a(i)-1), X2 is C 4-8 Aryl, preferably aromatic C6 aryl, such as benzene, which is optionally substituted, and X3 is selected from O and NZ. Preferably, in formula (II-a(i)), X1 is H.

[0068] In one embodiment of the methods disclosed herein, the EBP comprises a chemical structural unit of formula (III-a(i)):

[0069]

[0070] in,

[0071] X1 is selected from H, R or -C(=O)R,

[0072] X2 Selected from C 4-8 Cycloalkyl, C 4-8 Heterocycloalkyl, C 4-8 Aryl and C 4-8 Heteroaryl, each of which may be optionally substituted by one or more of -OH, -NH2, -Q, -CQ3, -OCH3, wherein each Q is independently hydrogen, halogen, methyl, phenyl or benzyl,

[0073] X3 can be selected from CR2, NZ, O and S,

[0074] Where R is selected from C 1-6 Alkyl, C 1-6 Heteroalkyl, C 1-6 Alkoxy, C 1-6 Allyl, C 1-6 Heteroallyl, C 4-8 Cycloalkyl, C 4-8 Heterocycloalkyl, C 4-8 Aryl and C 4-8 Heteroaryl, each of which may be optionally substituted by one or more of -OH, -NH2, -L, -CL3, -OCH3, wherein L is halogen,

[0075] wherein NZ represents an amine-based crosslinker and / or hardener selected from the group consisting of polyamide resins, poly(oxypropylene)diamines, 3-aminomethyl-3,5,5-trimethylcyclohexylamine, triethylenetetramine, tetraethylenepentamine, and amine-terminated trimethylolpropane tris[poly(propylene glycol)]ether (T-403), and

[0076] Wherein n represents that the structural unit is repeated, and can be an integer greater than 1.

[0077] Preferably, X1 in formula (III-a(i)) is H, X2 is C 4-8 Aryl, preferably aromatic C6 aryl such as benzene, is optionally substituted, and X3 is selected from O and NZ.

[0078] In one embodiment of the methods disclosed herein, the EBP comprises a chemical structural unit of formula (II-a(i)-2), formula (II-a(i)-3), or formula (II-a(i)-4):

[0079]

[0080] in

[0081] X1 is selected from H, R or -C(=O)R,

[0082] X2 Selected from C 4-8 Cycloalkyl, C 4-8 Heterocycloalkyl, C 4-8 Aryl and C 4-8 Heteroaryl, each of which may be optionally substituted by one or more of -OH, -NH2, -Q, -CQ3, -OCH3, wherein each Q is independently hydrogen, halogen, methyl, phenyl or benzyl,

[0083] X3 can be selected from CR2, NZ, O and S,

[0084] Where R is selected from C 1-6 Alkyl, C 1-6 Heteroalkyl, C 1-6 Alkoxy, C 1-6 Allyl, C 1-6 Heteroallyl, C 4-8 Cycloalkyl, C 4-8 Heterocycloalkyl, C 4-8 Aryl and C 4-8 Heteroaryl, each of which may be optionally substituted by one or more of -OH, -NH2, -L, -CL3, -OCH3, wherein L is halogen,

[0085] wherein NZ represents an amine-based crosslinker and / or hardener selected from polyamide resins, poly(oxypropylene)diamine, 3-aminomethyl-3,5,5-trimethylcyclohexylamine, triethylenetetramine, tetraethylenepentamine, and amine-terminated trimethylolpropane tri[poly(propylene glycol)]ether (T-403).

[0086] In another embodiment of the methods disclosed herein, the EBP comprises a chemical structural unit of formula (III-b):

[0087]

[0088] in,

[0089] R represents phenyl or its derivatives, such as bisphenol or its derivatives,

[0090] X1 represents H, R1 or -C(=O)R1, wherein R1 can be C1-6 Alkyl, C 1-6 Heteroalkyl, C 1-6 Alkoxy, C 1-6 Allyl, C 1-6 Heteroallyl, C 4-8 Cycloalkyl, C 4-8 Heterocycloalkyl, C 4-8 Aryl and C 4-8 Heteroaryl, each of which may be optionally substituted by one or more of -OH, -NH2, -L, -CL3, -OCH3, -OCL3, wherein L is halogen, and

[0091] n represents that the structural unit is repeated, and can be an integer greater than 1.

[0092] Preferably, X1 in formula (III-b) is H.

[0093] In one embodiment of the present invention, n defined in formula (III-b) is an integer of at least 1, such as at least 2, such as at least 5, such as at least 10, such as at least 50, such as at least 100, such as at least 200, such as at least 500, such as at least 1000, such as at least 10000.

[0094] In one embodiment of the present invention, n as defined in formula (III-b) is an integer between 1 and 1000, such as 1 to 500, such as 1 to 400, such as 1 to 300, such as 1 to 200, such as 1 to 100.

[0095] In one embodiment of the present invention, n as defined in formula (III-b) is an integer between 50 and 100, such as 100 to 200, such as 200 to 300, such as 300 to 500, such as 500 to 700, such as 700 to 1000.

[0096] In one embodiment of the present invention, R in formula (III-b) is bisphenol or a derivative thereof, and may be of general formula (IV):

[0097]

[0098] in,

[0099] Each of R1, R2, R3, R4, R5 and R6 can be independently selected from -H, -F, -Cl, -Br, -OH, -CH3, -CF3, -OCF3, phenyl, pyridyl, -CN, -NO2, C 1-6Alkyl, or wherein R1 and R2 may be combined together to form a cyclohexyl moiety, the cyclohexyl moiety is optionally substituted with one or more selected from -CH3 and -CF3, and wherein the broken bond of formula (IV) represents the position of the phenolic oxygen of the bisphenol.

[0100] Preferably, R1, R2, R3, R4, R5 and R6 in formula (IV) are each independently selected from -H, -F, -Cl, -Br, -CH3, -CF3 or phenyl.

[0101] In another embodiment of the methods disclosed herein, the EBP comprises a chemical structural unit of formula (III-ca):

[0102]

[0103] The structural unit of formula (III-ca) may contain 1 to 4 R3 and R4, wherein R1, R2, R3 and R4 are each independently selected from H, C 1-6 Alkyl, C 1-6 alkenyl, CF3, F, Cl, Br, OH, NO2, NH2, phenyl, or wherein R1 and R2 can together form a C6 cycloalkyl, and wherein R5 is selected to be O or NZ, wherein NZ represents an amine-based crosslinker and / or hardener selected from polyamide resins, poly(oxypropylene)diamine, 3-aminomethyl-3,5,5-trimethylcyclohexylamine, triethylenetetramine, tetraethylenepentamine and amine-terminated trimethylolpropane tri[poly(propylene glycol)] ether (T-403).

[0104] In one embodiment, the amine-based crosslinker and / or hardener of formula (III-ca) may be further linked to another bisphenol entity of another epoxy polymer chain, thereby resulting in extensive crosslinking.

[0105] In another embodiment of the methods disclosed herein, the EBP comprises a chemical structural unit of formula (III-cb):

[0106]

[0107] The structural unit of formula (III-cb) may contain 1 to 4 R3 and R4, wherein R1, R2, R3 and R4 are each independently selected from H, C 1-6 Alkyl, C 1-6 alkenyl, CF3, F, Cl, Br, OH, NO2, NH2, phenyl, or wherein R1 and R2 can together form a C6 cycloalkyl.

[0108] In another embodiment of the methods disclosed herein, the EBP comprises a chemical structural unit of formula (III-cc):

[0109]

[0110] The structural unit of formula (III-cc) may contain 1 to 4 R3 and R4, wherein R1, R2, R3 and R4 are each independently selected from H, C 1-6 Alkyl, C 1-6 alkenyl, CF3, F, Cl, Br, OH, NO2, NH2, phenyl, or wherein R1 and R2 can together form a C6 cycloalkyl, and wherein NZ represents an amine-based crosslinker and / or hardener selected from polyamide resins, poly(oxypropylene)diamine, 3-aminomethyl-3,5,5-trimethylcyclohexylamine, triethylenetetramine, tetraethylenepentamine and amine-terminated trimethylolpropane tri[poly(propylene glycol)] ether (T-403).

[0111] In one embodiment of the present invention, n defined in formula (III-ca), formula (III-cb) and formula (III-cc) is an integer of at least 1, for example at least 2, for example at least 5, for example at least 10, for example at least 50, for example at least 100, for example at least 200, for example at least 500.

[0112] In one embodiment of the present invention, n defined in Formula (III-ca), Formula (III-cb) and Formula (III-cc) is an integer between 1 and 1000, for example, 1 to 500, for example, 1 to 400, for example, 1 to 300, for example, 1 to 200, for example, 1 to 100.

[0113] In one embodiment of the present invention, n defined in Formula (III-ca), Formula (III-cb) and Formula (III-cc) is an integer between 50 and 100, for example, 100 to 200, for example, 200 to 300, for example, 300 to 500, for example, 500 to 700, for example, 700 to 1000.

[0114] In another embodiment of the methods disclosed herein, the EBP comprises a chemical structural unit of formula (III-da):

[0115]

[0116] wherein R5 is selected to be O or NZ, wherein NZ represents an amine-based crosslinker and / or hardener selected from polyamide resins, poly(oxypropylene)diamines, 3-aminomethyl-3,5,5-trimethylcyclohexylamine, triethylenetetramine, tetraethylenepentamine, and amine-terminated trimethylolpropane tris[poly(propylene glycol)]ether (T-403), and wherein Ar represents an aromatic ring, such as phenyl or naphthyl, preferably phenyl. The aromatic rings of formula (III-da) may be substituted or crosslinked in the polymer, for example representing another bisphenol or bisphenol diglycidyl ether derived moiety.

[0117] In another embodiment of the methods disclosed herein, the EBP comprises a chemical structural unit of formula (III-db):

[0118]

[0119] wherein Ar represents an aromatic ring, such as phenyl or naphthyl, preferably phenyl. The aromatic rings of formula (III-db) may be substituted or cross-linked in the polymer, for example to represent another bisphenol or bisphenol diglycidyl ether derived moiety.

[0120] In another embodiment of the methods disclosed herein, the EBP comprises a chemical structural unit of formula (III-dc):

[0121]

[0122] wherein NZ represents an amine-based crosslinker and / or hardener selected from polyamide resins, poly(oxypropylene)diamines, 3-aminomethyl-3,5,5-trimethylcyclohexylamine, triethylenetetramine, tetraethylenepentamine, and amine-terminated trimethylolpropane tris[poly(propylene glycol)]ether (T-403), and wherein Ar represents an aromatic ring, such as phenyl or naphthyl, preferably phenyl. The aromatic rings of formula (III-dc) may be substituted or crosslinked in the polymer, for example representing another bisphenol or bisphenol diglycidyl ether derived moiety.

[0123] In one embodiment of the present disclosure, the deconvoluted EBP in the method comprises one or more cross-linking agents. In one embodiment disclosed herein, the cross-linking agent is selected from polyamide resin, poly(oxypropylene) diamine, 3-aminomethyl-3,5,5-trimethylcyclohexylamine, triethylenetetramine, tetraethylenepentamine and amine-terminated trimethylolpropane tris[poly(propylene glycol)] ether (T-403).

[0124] In one embodiment of the present invention, the crosslinking agent may be selected from conventionally used epoxy hardeners known to those skilled in the art.

[0125] In one embodiment of the present disclosure, the EBP comprises one or more epoxy hardeners selected from polyamide resins, poly(oxypropylene) diamines, 3-aminomethyl-3,5,5-trimethylcyclohexylamine, triethylenetetramine, tetraethylenepentamine, and amine-terminated trimethylolpropane tris[poly(propylene glycol)] ether (T-403).

[0126] In one embodiment of the method disclosed herein, the monomers contained in the EBP are selected from bisphenol A, bisphenol AP, bisphenol AF, bisphenol B, bisphenol BP, bisphenol C, bisphenol E, bisphenol F, bisphenol G, bisphenol M, bisphenol S, bisphenol P, bisphenol PH, bisphenol TMC, bisphenol Z and their derivatives.

[0127] In one embodiment of the present disclosure, the monomer in the EBP comprises bisphenol A or a derivative thereof.

[0128] In one embodiment of the present disclosure, the EBP is selected from the group consisting of bisphenol A-based EBP, bisphenol AP-based EBP, bisphenol AF-based EBP, bisphenol B-based EBP, bisphenol BP-based EBP, bisphenol C-based EBP, bisphenol C-based EBP, bisphenol E-based EBP, bisphenol F-based EBP, bisphenol G-based EBP, bisphenol M-based EBP, bisphenol S-based EBP, bisphenol P-based EBP, bisphenol PH-based EBP, bisphenol TMC-based EBP, bisphenol Z-based EBP. In another embodiment, the EBP is bisphenol A-based EBP.

[0129] The EBP used in the method of the present invention is generally insoluble in any conventional solvent. Therefore, the base-mediated deconvolution reaction is limited to surface reactivity, which can be very time-consuming. Therefore, before performing the method, the EBP can be chopped, ground, filed or similarly reduced to a powder, such as using a flat file, to obtain a larger surface area. Therefore, in one embodiment of the present disclosure, the EBP is a powder or granules. The powder or granules of the polymer can be characterized by standard techniques known to those of ordinary skill in the art of physical science, such as dynamic light scattering according to ISO 13320:2020, and by such as D 50 and D 90 (or other numbers between 1 and 100). Therefore, D n The value of refers to a particle size smaller than which n% of the measured samples have a particle size smaller than this particle size.

[0130] In one embodiment of the present disclosure, the EBP powder size distribution is characterized by D 90Less than 1000 μm, for example less than 900 μm, for example less than 800 μm, for example less than 700 μm, for example less than 600 μm, for example less than 500 μm, for example less than 400 μm, for example less than 300 μm, for example less than 200 μm, for example less than 100 μm.

[0131] In one embodiment of the present disclosure, the EBP powder size distribution is characterized by D 90 Less than 500 μm, for example less than 400 μm.

[0132] In one embodiment of the present invention, the EBP powder size distribution is characterized by D 90 It is 100μm to 1000μm, for example 100μm to 200μm, for example 200μm to 275μm, for example 275μm to 325μm, for example 325μm to 350μm, for example 350μm to 375μm, for example 375μm to 400μm, for example 400μm to 425μm, for example 425μm to 500μm, for example 500μm to 600μm, for example 600μm to 700μm, for example 700μm to 800μm, for example 800μm to 1000μm.

[0133] In one embodiment of the present disclosure, the EBP powder size distribution is characterized by D 90 It is 200 μm to 500 μm, for example, 300 μm to 400 μm.

[0134] In one embodiment of the present invention, the EBP powder size distribution is characterized by D 50 Less than 300 μm, such as less than 250 μm, such as less than 225 μm, such as less than 200 μm, such as less than 175 μm, such as less than 150 μm.

[0135] In one embodiment of the present disclosure, the EBP powder size distribution is characterized by D 50 Less than 225 μm, for example less than 175 μm.

[0136] In one embodiment of the present disclosure, the EBP powder size distribution is characterized by D 50 50 μm to 300 μm, for example 50 μm to 75 μm, for example 75 μm to 100 μm, for example 100 μm to 125 μm, for example 125 μm to 150 μm, for example 150 μm to 175 μm, for example 175 μm to 250 μm, for example 250 μm to 300 μm.

[0137] In one embodiment of the present disclosure, wherein the EBP powder size distribution is characterized by D 5075 μm to 200 μm, for example, 100 μm to 175 μm.

[0138] In one embodiment of the present disclosure, the methods described herein are performed in a closed container, such as a closed container under autogenous pressure. "Autogenous pressure" refers to the pressure within the closed container during the reaction being ambient pressure or pressure generated in other ways, such as when the reaction is heated or gas is generated within the closed container. In other embodiments, the methods described herein can be performed in an open container or vessel in direct contact with the atmosphere.

[0139] In one embodiment of the present disclosure, the autogenous pressure is at least 14.5 to 145 psi.

[0140] In one embodiment of the present disclosure, the method described herein is carried out in an inert atmosphere, for example, in an inert atmosphere mainly consisting of nitrogen (N2) or argon (Ar). In another embodiment, the method is carried out in a non-inert atmosphere, for example, using ambient air.

[0141] In order to increase the conversion rate of the reaction to a practical level, the suspension comprising the base, the solvent and the EBP polymer is heated to above room temperature. In one embodiment of the present disclosure, the suspension is heated to a temperature of at least 130°C, such as at least 140°C, such as at least 150°C, such as at least 160°C, such as at least 170°C, such as at least 180°C, such as at least 190°C, such as at least 200°C, such as at least 210°C, such as at least 220°C, such as at least 230°C, such as at least 240°C, such as at least 250°C. Preferably, the suspension is heated to at least 130°C, more preferably at least 170°C, and most preferably at least 190°C.

[0142] In another embodiment of the present disclosure, the suspension is heated to a temperature between 130° C. and 250° C., such as 130° C. and 150° C., such as 150° C. and 170° C., such as 170° C. and 190° C., such as 190° C. and 210° C., such as 210° C. and 230° C., such as 230° C. and 250° C. Preferably, the suspension is heated to a temperature between 130° C. and 230° C., more preferably between 170° C. and 210° C.

[0143] In one embodiment of the present disclosure, the suspension is heated for at least 2 hours, such as at least 4 hours, such as at least 8 hours, such as at least 16 hours, such as at least 24 hours.

[0144] In one embodiment of the present disclosure, the suspension is heated for a period of 2 hours to 10 days, such as 2 hours to 4 hours, such as 4 hours to 8 hours, such as 8 hours to 16 hours, such as 16 hours to 24 hours, such as 24 hours to 2 days, such as 2 days to 3 days, such as 3 days to 5 days, such as 5 days to 10 days. Preferably, the suspension is heated for 16 hours to 3 days, more preferably 16 hours to 2 days, most preferably 24 hours to 2 days.

[0145] It is within the scope of the present disclosure to provide methods that allow for the deconvolution of EBP that is cured by itself or that is used as a matrix for fibers (e.g., to prepare FREBP composites). This makes the present invention attractive from a circular economy perspective. Traditionally studied methods focused on fiber recovery rely on pyrolysis, discharge, or supercritical solvents. These harsh conditions are impractical for industrial scale. In addition, they typically destroy the polymer matrix rather than deconstruct it, ultimately damaging the fibers. Due to the huge challenges of the physical and chemical stability of cured epoxy resins, chemical deconstruction methods are severely underdeveloped, however, recent studies have shown that some FREBPs can be decomposed using acetic acid to recover the fibers.

[0146] In order to demonstrate that the method claimed in the present disclosure can also be used to deconstruct resin from fiber-reinforced composites, the method needs to withstand the residues produced by the treatment that can be used to separate the fibers from the resin. It is known in the art that acetic acid can be used to swell cured epoxy resins to achieve more effective catalytic deconstruction. Therefore, it is necessary to demonstrate that the method of the present disclosure is also applicable to EPB that has been subjected to an acetic acid swelling step. However, in one embodiment of the present disclosure, the EBP has not been subjected to an acetic acid swelling step before the step of contacting the EBP with a suspension comprising at least one aprotic non-polar organic solvent and an oxygen-containing base.

[0147] In one embodiment of the present disclosure, the epoxy-based polymer may be mixed with fibers, such as in a fiber-reinforced composite material, particularly a composite material wherein the fibers are glass fibers or carbon fibers.

[0148] In one embodiment of the method disclosed herein, the fiber in the FREBP is selected from glass fiber, carbon fiber, cellulose, lignin, aramid and asbestos. In one embodiment of the present disclosure, the fiber in the FREBP is glass fiber and / or carbon fiber.

[0149] In one embodiment of the present disclosure, the method described herein further comprises the step of pretreating the epoxy-based polymer, or when EBP is present in the presence of fibers in the FREBP composite, the composite may further comprise the step of pretreating the composite to achieve fiber separation.

[0150] In one embodiment of the present disclosure, the pretreatment step includes contacting the epoxy-based polymer or composite thereof with a swelling agent.

[0151] The method of the present disclosure is carried out in a solvent, preferably an organic solvent with a high boiling point, such as a boiling point above 100° C. In the method of the present disclosure, it is also preferred that the solvent is a non-coordinating solvent, such as solvents known to those skilled in the art of chemical synthesis.

[0152] Therefore, in one embodiment of the invention, solvent is an organic solvent, preferably a non-coordinating and / or non-polar organic solvent. Hereinafter, non-polar (apolar) is considered to be equivalent to non-polar (non-polar). The difference between polar solvent and non-polar solvent is well known to those skilled in the art. It is generally believed that the solvent composed of hydrocarbons such as heptane, toluene, cymene and dimethylbenzene is non-polar. In another embodiment, the organic solvent is an aprotic solvent. In some embodiments, the organic solvent can be both non-polar and aprotic. Such terms are also known to those of ordinary skill in the art, and are widely used and accepted in the field of chemical synthesis.

[0153] In one embodiment of the present disclosure, the organic solvent is a solvent containing only carbon and hydrogen atoms. In a further embodiment, the organic solvent is selected from toluene, benzene, xylene, mesitylene, cumene, cymene and mixed xylenes, or a structural isomer of any one thereof, such as ortho, meta and para isomers known to those skilled in the art.

[0154] In one embodiment of the present disclosure, the organic solvent is selected from toluene, xylene, cymene or a structural isomer thereof.

[0155] In one embodiment of the present disclosure, the organic solvent is selected from benzene, toluene, cymene and xylene, such as p-cymene and o-xylene.

[0156] The method of the present invention utilizes at least one base to perform base-mediated deconstruction of epoxy-based polymers. In one embodiment of the present disclosure, the base is a nucleophilic base. In one embodiment of the present disclosure, the base is a non-nucleophilic base. In one embodiment of the present disclosure, the base is an oxygen-containing base or a nitrogen-containing base.

[0157] In one embodiment of the present disclosure, the base is an oxygen-containing base, such as a hydroxide selected from NaOH, LiOH, KOH, CsOH, RbOH, Ca(OH)2, Sr(OH)2 and Ba(OH)2; or an alcohol salt selected from n-butoxide, tert-butoxide, methanol, ethanol and isopropoxide, including sodium or potassium salts of these alcohol salts.

[0158] In one embodiment of the present disclosure, the base is selected from NaOH, KOH, NaOBu and NaOtBu, preferably NaOH or KOH.

[0159] In one embodiment of the present disclosure, the base is a nitrogen-containing base, for example, an amide selected from lithium diisopropylamide (LDA), lithium diethylamide (LDEA), sodium amide, lithium bis(trimethylsilyl)amide; or an amine selected from triethylamine, trimethylamine, diethylamine, dimethylamine, pyridine and ammonia.

[0160] In one embodiment of the method, the EBP is not subjected to a chemical treatment prior to contacting the EBP with a suspension comprising at least one aprotic non-polar organic solvent and an oxygen-containing base.

[0161] In one embodiment of the present disclosure, the base is not a nitrogen-containing base.

[0162] In one embodiment of the present disclosure, the method does not comprise or use one or both of hydrogen peroxide and / or ascorbic acid, such as does not comprise or use hydrogen peroxide, or does not comprise or use ascorbic acid.

[0163] Due to the complex and variable nature of crosslinked and / or cured epoxy polymer resins, it is difficult or even impossible to know the exact amount of target CO and / or CN linkages in the resin, and therefore difficult to add an equal amount of base. Therefore, the base is added as a weight percent (wt %) based on the weight of EBP.

[0164] In one embodiment of the present disclosure, the amount of base added is at least 10wt% of the weight of EBP, such as at least 20wt% of the weight of EBP, such as at least 30wt%, such as at least 40wt%, such as at least 50wt%, such as at least 60wt%, such as at least 70wt%, such as at least 100wt%, such as at least 150wt%, such as at least 200wt%, such as at least 300wt%, such as at least 400wt%.

[0165] In another embodiment of the present disclosure, the base is added in an amount of 10 wt % to 100 wt % of the weight of the EBP, for example, 10 wt % to 20 wt % of the weight of the EBP, for example, 20 wt % to 30 wt %, for example, 30 wt % to 40 wt %, for example, 40 wt % to 45 wt %, for example, 45 wt % to 50 wt %, for example, 50 wt % to 55 wt %, for example, 55 wt % to 60 wt %, for example, 60 wt % to 70 wt %, for example, 70 wt % to 80 wt %, for example, 80 wt % to 90 wt %, for example, 90 wt % to 100 wt %.

[0166] In one embodiment, the base is added in the range of 40 wt % to 60 wt %, preferably 50 wt %, based on the weight of the EBP. Example

[0167] General information

[0168] Unless otherwise noted, all reactions were set up and performed in a glove box under argon atmosphere. Unless otherwise noted, all chemicals were purchased from Sigma-Aldrich, Tokyo Chemical Industry (TCI), VWR Chemicals, or Strem Chemicals and used as received. Granular NaOH (98.6% purity) was purchased from VWR Chemicals and then crushed in a mortar to obtain a powder. THF, toluene, CH2Cl2, and MeCN were recovered from an MBraun SP-800 purification system, degassed with argon, and stored at The remaining solvents were purchased from Sigma-Aldrich, degassed with argon, and stored at molecular sieves and used without further purification.

[0169] Pre-painted aluminum sheets purchased in Macherey-Nagel Thin layer chromatography (TLC) was performed on Xtra SIL G / UV 254. Visualization of the product was achieved by UV irradiation (366 nm) and / or staining with potassium permanganate in water.

[0170] Flash column chromatography was performed using silica gel (0.040-0.063 mm / 230-400 mesh) ASTM purchased from Macherey-Nagel. Automated flash column chromatography (AFCC) was performed using an Interchim PuriFlash XS520 Plus with 30 μm prepacked columns. Crude 545 for filtering.

[0171] Gas chromatography-mass spectrometry (GC-MS) was performed using an Agilent 8890 gas chromatograph coupled to an Agilent 5977B mass selective detector.

[0172] High Resolution Mass Spectrometry (HRMS): ESI(+) spectra were measured on a Bruker Maxis Impact Spectrometer. MALDI spectra were measured on a Bruker Autoflex maX MALDI-TOF MS spectrometer using a MTP 384 target plate polished steel BC.

[0173] NMR spectra: Unless otherwise stated, 1 H NMR, 13 C NMR and 31P NMR spectra were recorded at 25°C on a Broker 400 MHz Ascend spectrometer. Chemical shifts are expressed as δ values ​​(ppm) with reference to the residual solvent signal of the deuterated solvent. Peak types are indicated as follows: s, singlet; d, doublet; t, triplet; m, multiplet; q, quartet. DEPT-90 and / or DEPT-135 spectra were used to report 13 The multiplicity of C NMR spectra was assigned. Coupling constants J are reported in Hertz (Hz). Spectra were calibrated according to the residual solvent signal. NMR spectra were processed using MestReNova version 14.2.1-27684.

[0174] The particle size distribution was determined using a Malvern Mastersizer 2000 instrument with a Hydro S dispersion device (Malvern Panalytical). The measurement was performed using dynamic light scattering, and particles with a size interval of 0.02-2000 μm were measured. In accordance with ISO 13320:2020, the sample was measured with a stirring speed of 3500 rpm and laser wavelengths of 633 nm and 466 nm and under continuous stirring to avoid precipitation. For size distribution modeling of spherical particle samples, the refractive index was assumed to be 1.5 and the absorptivity was 0.1. The results are reported as the average of three measurements.

[0175] Example 1 - Preparation of epoxy model

[0176] Step 1. Preparation of (4-(2-(4-methoxyphenyl)propan-2-yl)phenol)

[0177]

[0178] To a suspension of K2CO3 (10.4 g, 75.0 mmol) in 100 mL of acetone in a 250 mL round-bottom flask equipped with a stirring bar, bisphenol A (11.4 g, 50.0 mmol) was added while stirring at room temperature under air. Methyl iodide (7.1 g, 50.0 mmol) was then added dropwise via a syringe, and the mixture was stirred overnight at room temperature. The reaction mixture was then filtered and the organic phase was concentrated under vacuum. The mixture was then flash column chromatographed on silica gel using a gradient of 15 / 1 pentane / ethyl acetate to 10 / 1 pentane / ethyl acetate to give a colorless, highly viscous oil, Me-BPA, in a yield of 37% (4.50 g, 18.6 mmol).

[0179] 1H NMR (CDCl3, 400MHz, 25℃): δ=7.16 -7.12(m,2H),7.11-7.08(m,2H),6.82-6.78(m,2H),6.74-6.71(m,2H),4.54(s,1H),3.78(s,3H),1.64(s,6H)ppm.

[0180] Step 2. Preparation of epoxy model (1,3-bis(4-(2-(4-methoxyphenyl)propan-2-yl)phenoxy)propan-2-ol) Preparation

[0181]

[0182] Me-BPA (2.42g, 10.0mmol) and 50mL H in the 100mL flask equipped with stirring rod add NaOH (0.44g, 11mmol) in the mixture of O, and the mixture was stirred for 10 minutes.Then, add epichlorohydrin (0.46g, 5mmol) and the mixture was heated to reflux overnight.Then, the reaction mixture was cooled to room temperature and extracted with DCM (30mL x 3).Organic phase Na sO dry and concentrate under vacuum.Then by rapid column chromatography purification mixture, use the gradient of pentane / ethyl acetate of 10 / 1 to pentane / ethyl acetate of 5 / 1, obtain model 1, be colorless high viscosity oily thing.In addition, heating under vacuum removes solvent residue, obtains required product, and productive rate is 50% (1.37g, 2.5mmol).

[0183] 1 H NMR (CDCl3, 400MHz, 25℃): δ=7.16-7.12(m,8H),6.84-6.78(m,8H),4.36(h,J=5.3 Hz,1H),4.15–4.09(m,4H),3.78(s,6H),2.54(d,J=4.0Hz,1H),1.64(s,12H)ppm; 13 CNMR (CDCl3, 101 MHz, 25°C): δ = 157.5 (s, 2C), 156.3 (s, 2C), 143.9 (s, 4C), 143.1 (s, 2C), 127.9 (s, 4C), 127.8 (d, 4C), 114.0 (d, 4C), 113.4 (d, 4C), 68.9 (d, 1C), 68.7 (t, 2C), 55.3 (q, 2C), 41.8 (s, 2C), 31.2 (q, 4C) ppm; HRMS (ESI+): calculated value [M+Na] + =[C 35 H 40 O5+Na] + 563.2768; measured value 563.2762.

[0184] Example 2 - Proof of concept: Degradation of epoxy resin model using only base without metal catalyst

[0185] The use of metal catalysts, especially those based on metals such as ruthenium, palladium, rhodium, platinum and gold, is extremely undesirable in industrial-scale applications, as it often renders otherwise available reactions unfeasible from a financial point of view. For this reason, it was decided to attempt the deconstruction of the epoxy model without any metal catalyst, using only a base and a non-coordinating solvent such as toluene at elevated temperature and pressure. The following procedure was employed.

[0186]

[0187] 1 equivalent (0.1 mmol) of the epoxy model substrate was charged into a 10 ml CO tube. Under an air atmosphere, 2 ml of toluene and 6 equivalents (0.6 mmol) of NaOH were added and the reaction vessel was sealed. The use of 6 equivalents of NaOH was determined based on previously unpublished data showing that, under the same reaction conditions, 6 equivalents provided the best yield, while fewer equivalents resulted in lower isolated yields. The reaction mixture was then stirred at 650 rpm in an aluminum block at 190 °C for 24 hours. The reaction mixture was then cooled to room temperature, quenched with 2 ml of 4M aqueous HCl and extracted with ethyl acetate. Thereafter, either (for isolated yield) the solvent was removed in vacuo and the product was isolated using column chromatography, or 1,3,5-trimethoxybenzene was added as an internal standard and purified in CDCl3 1 H NMR spectroscopy was performed to determine the yield without isolation to account for any mechanical losses.

[0188] Table 1 - Conversion of epoxy models and yield of bisphenol A obtained in Example 2.

[0189] entry change Conversion rate (%) Yield (%) 1 none <![CDATA[60 a) ]]> <![CDATA[33 a) ]]>

[0190] a) pass 1 H NMR measurement. 0.1 mmol of 1,3,5-trimethoxybenzene was used as an internal standard. 1 H NMR measurements were performed to confirm conversion (remaining amount of substrate) and yield.

[0191] Example 3 - Screening of solvents, reaction temperatures and times for base-mediated deconstruction of commercially available epoxy resins

[0192] Based on the encouraging proof-of-concept results obtained in Example 2, which showed that the epoxy model system could be deconstructed using only base as a medium, the real-world epoxy resin Airstone TM760E / 766H The same reaction with several modifications was examined to optimize the reaction parameters.

[0193] Sample preparation

[0194] Since the cross-linked resin tested in this and the following examples is insoluble in the tested solvents, the degradation to basic components by chemical reaction is limited to reactions occurring on the surface of the resin. Therefore, in order to maximize the surface area and reduce the reaction time, a flat file is used as a tool to file the solidified resin block into powder. TM 760E / 766H (as well as UHU plus endfest two-component glue, Roizefar epoxy resin and Sicomin SR infugreen810 / SD8822 in Example 4) were crushed into powder. Dynamic light scattering ( Figure 4 ) confirmed Airstone TM The powder sizes for 760E / 766H and since the same tooling and procedures were used it was assumed that the powders for the remaining resins were of similar size.

[0195] Airstone TM Dynamic light scattering measurements of 760E / 766H powders showed that 10% of the particles had a diameter of less than 32.8 μm (D10 value), 50% of the particles had a diameter of more than 134.1 μm, 50% of the particles had a diameter of less than 134.1 μm (D50 value), and 90% of the particles had a diameter of less than 380.5 μm (D90 value).

[0196] Since toluene generates relatively high pressure at 190 °C, similar aprotic and non-coordinating solvents with higher boiling points were considered (Table 2). Both o-xylene (bp 144 °C) and p-isopropylbenzene (bp 177 °C) gave comparable recovered BPA yields of 75% after 24 h (entries 2 and 3). p-isopropylmethylbenzene was of particular interest because this non-toxic solvent can be obtained from biomass. No significant differences in yield due to boiling point were observed as long as the boiling point was above 100 °C.

[0197] The process exhibited a clear temperature dependence as evidenced by the decrease in BPA yield from 79% at 190°C to 59% at 170°C and further decrease until no BPA was detectable when the reaction was carried out at 110°C (entries 1 and 4-7).

[0198] Extending the reaction time to 2 days did not result in significant improvement compared to the 24 h reaction time (entry 8). We conclude that this approach can be used to obtain TMThe maximum amount of BPA recovered in 760E / 766H was 81%. The remaining BPA is likely adjacent to crosslinked structural units that are more difficult to break. Table 2 - Screening of solvents, temperatures, and reaction times to optimize base-mediated deconstruction of epoxy resins to Airstone TM Take 760E / 766H as an example

[0199]

[0200]

[0201] a) Product yields isolated by flash column chromatography; b) TBAC = tetrabutylammonium chloride

[0202] The results can be summarized to show that the temperature should be as high as possible, preferably at least 190°C for the indicated volume and reaction vessel. The results also show that there are no particularly preferred solvents as long as they are aprotic, non-polar and non-coordinating. Toluene, o-xylene and p-isopropylbenzene appear to be equally useful in this regard.

[0203] Example 4 - General Procedure for Deconvolution of Epoxy Resin and Recovery of Bisphenol A

[0204] General procedure: 100 mg of resin powder was placed in a 40 ml CO tube. Under air, 4.2 ml of toluene and 1.26 mmol of base were added and the reaction vessel was sealed. The reaction mixture was stirred at 300 rpm in an aluminum block at 190 °C for 24 hours. The reaction mixture was then cooled to room temperature, quenched with 10 ml of 4M HCl aqueous solution and extracted with ethyl acetate. Then, 1 g of diatomaceous earth was added to the mixture, and after vacuum concentration, the mixture was subjected to column chromatography to obtain bisphenol A. Column chromatography was performed using a gradient of 6 / 1 pentane / ethyl acetate to 4 / 1 pentane / ethyl acetate to obtain bisphenol A.

[0205] Follow the general procedure described above for Airstone TM Deconstruction of 760E / 766H (BPA content is about 43wt%, see Figure 2 ). Airstone TM 760E / 766H is an infusion resin for wind turbine systems (such as wind turbine blades) developed by Olin Provided and prepared from the following reagents: bis-[4-(2,3-epoxypropoxy)phenyl]propane (DGEBA), 1,4-bis(2,3-epoxypropoxy)butane (BDDE), poly(oxypropylene)diamine, and 3-aminomethyl-3,5,5-trimethylcyclohexylamine.

[0206] According to the existing safety data sheet, 760E contains

[0207] 75.0% bis-[4-(2,3-epoxypropoxy)phenyl]propane (DGEBA); and

[0208] · <25.0% 1,4-bis(2,3-epoxypropoxy)butane (BDDE).

[0209] And 766H contains

[0210] ≤50.0<75.0% poly(oxypropylene)diamine; and

[0211] ≤25.0<50.0% of 3-aminomethyl-3,5,5-trimethylcyclohexylamine.

[0212] The general procedure described above was carried out using 100 mg of resin powder, 50.0 mg (1.26 μmol, 50.0 wt%) of NaOH and 4.2 ml of toluene. Column chromatography gave colorless solid BPA, with the remainder being a brown, highly viscous oil. Yield of BPA (based on theoretical maximum): 34.7 mg (80.7%).

[0213] Follow the general procedure described above Two-component glue (UHU plus endfest2-K-Epoxidharzkleber 45670) (BPA content is about 34wt%, see Figure 3 Deconstruction of a). The adhesive was prepared by mixing the two separate components in a ratio of 1 g to 1 g and then allowing to harden overnight at room temperature.

[0214] The above general procedure was carried out using 100 mg of resin powder, 50.0 mg (1.26 μmol, 50.0 wt%) of NaOH and 4.2 ml of toluene. Column chromatography gave colorless solid BPA, and the remainder was a brown, highly viscous oil. Yield of BPA (based on theoretical maximum): 28.5 mg (83.8%).

[0215] Follow the general procedure described above Deconstruction of epoxy resin (BPA content is about 30wt%, see Figure 3 b). A two-component resin was produced by Shenzhen Fengao Technology Co., Ltd. and was prepared by mixing the two separate components in a ratio of 1 g to 1 g and then allowing to harden overnight at room temperature.

[0216] The general procedure described above was carried out using 100 mg of resin powder, 50.0 mg (1.26 μmol, 50.0 wt%) of NaOH and 4.2 ml of toluene. Column chromatography gave BPA as a colorless solid and the remainder as a brown highly viscous oil.

[0217] Yield of BPA (based on the theoretical maximum): 25.9 mg (86.3%). In addition, 12.2 mg of phenol were also isolated separately.

[0218] Sicomin SRinfugreen produced by Sicomin Epoxy Systems was prepared according to the general procedure described above. TM Deconstruction of 810 / SD8822 (BPA content is about 36wt%, see Figure 3 c) The resin was prepared as follows: SRinfugreen TM 810 (100 g) was mixed with hardener SD8822 (32.0 g), then degassed under vacuum for 20 min, poured into a preheated silicone mold (50°C), and cured at 50°C for 1 h and at 80°C for 3 h to obtain a hardened resin.

[0219] According to the existing safety data sheet, SR infugreen TM 810 contains:

[0220] · 50 ≤ x % < 100 bisphenol A-(epichlorohydrin); epoxy resin (number average molecular weight ≤ 700);

[0221] 10≤x%<25 of 1,4-bis(2,3-epoxypropoxy)butane (BDDE); and

[0222] · 2.5≤x%<10 bisphenol-F-(epichlorohydrin); epoxy resin (number average molecular weight ≤700).

[0223] SD8822 contains:

[0224] 50 ≤ x % < 100 of 3-aminomethyl-3,5,5-trimethylcyclohexylamine;

[0225] 25 ≤ x % < 50 of poly(oxypropylene)diamine; and

[0226] · 2.5≤x%<10 of amine terminated trimethylolpropane tri[polypropylene glycol] ether.

[0227] The above general procedure was carried out using 100 mg of resin powder, 50.0 mg (1.26 μmol, 50.0 wt%) of NaOH and 4.2 ml of toluene. Column chromatography gave colorless solid BPA, and the remainder was a brown, highly viscous oil. Yield of BPA (based on theoretical maximum): 21.0 mg (58.3%).

[0228] Taken together, these results indicate that the method described here can be used to degrade a variety of commercially available EBPs, allowing for the recovery of BPA. This highlights the great potential of this method for recycling such materials.

[0229] Example 5 - Cured Airstone TM Scale-up experiment of 760E / 766H resin

[0230]

[0231] Following the general procedure above, use powdered Airstone TM 760E / 766H (500 mg), NaOH (250 mg, 50 wt%), o-xylene (15 ml) were reacted in a 40 ml CO tube (SyTracks) at 190° C. and 300 rpm under air. After 3 days, the reaction was cooled to room temperature and quenched with HCl (4M, 8 mL). The reaction mixture was extracted with EtOAc (6 mL x 4) and: i) separated on silica using automated silica gel column chromatography using a gradient of 100% heptane to 100% ethyl acetate, or ii) dried over MgSO4 and the solvent removed under vacuum.

[0232] The above method i) produced BPA as an off-white solid with a yield of 158 mg (73%).

[0233] R f (pentane / ethyl acetate 4 / 1, silica gel) = 0.21; 1 H NMR (CDCl3, 400MHz, 25℃): δ=7.11–7.07(m,4H), 6.76–6.70(m,4H), 4.57(s,2H), 1.62(s,6H)ppm.

[0234] The above method ii) produced 229 mg of crude BPA as a dark, highly viscous oil. 1 Analysis of crude BPA by H NMR spectroscopy showed acceptable purity for further use in synthetic purposes ( Figure 5 ). 1 H NMR (CDCl3, 400MHz, 25℃): δ=7.06–7.03(m,4H), 6.73–6.70(m,4H), 2.99(s,2H), 1.58(s,6H)ppm.

[0235] This example demonstrates that the process is not limited to small scale recycling and that the amount of resin can be increased approximately five-fold without any significant adverse effect on the BPA yield.

[0236] Example 6 - Cured Airstone TM Deconvolution of resin in fiber reinforced composites of 760E / 766H resin

[0237] In order to demonstrate that the method claimed in the present disclosure can also be used to deconstruct resin from fiber-reinforced composites, the method needs to be tolerant to residues resulting from the treatment used to separate the fibers from the resin. It has been previously reported that acetic acid can physically break up thermosetting epoxy resins. Furthermore, the first commercial blade designed for such separation relied on separation by acid treatment. In order to investigate the compatibility of the base-mediated deconstruction method, Airstone TM The transparent castings of 760E / 766H were immersed in acetic acid in a beaker for two months ( Figure 6 A). During this time, the cast block partially broke up. The solvent was poured off and the resin fragments were then left to dry in air at room temperature for three days ( Figure 6 B). Collect the particles that accumulate at the bottom of the beaker ( Figure 6 C) and reacted it with 50 wt% NaOH in toluene in air at 190°C for 24 hours without any further treatment. TM 24.1 mg of BPA was recovered in the resin. Unfortunately, the percentage yield cannot be reported because the swelling of the epoxy resin does not allow for an approximate calculation of the weight percentage of BPA in the resin. However, this example still supports the feasibility of combining the developed chemical deconstruction with an acid-initiated treatment, which enables the separation of fibers from resin in fiber-reinforced epoxy composites.

[0238] project

[0239] 1. A method of deconvoluting an epoxy-based polymer (EBP), the method comprising providing the EBP, and further comprising the step of contacting the EBP with a solvent system comprising at least one organic solvent and a base to form a suspension.

[0240] 2. The method according to the preceding item, wherein the EBP comprises a chemical structural unit of formula (III-a)

[0241]

[0242] in,

[0243] X1 is selected from H, R or -C(=O)R, wherein R can be C 1-6 Alkyl, C 1-6 Heteroalkyl, C 1-6 Alkoxy, C 1-6 Allyl, C 1-6Heteroallyl, C 4-8 Cycloalkyl, C 4-8 Heterocycloalkyl, C 4-8 Aryl and C 4-8 Heteroaryl, each of which may be optionally substituted with one or more of -OH, -NH2, -L, -CL3, -OCH3, wherein L is halogen;

[0244] X2 Selected from C 4-8 Cycloalkyl, C 4-8 Heterocycloalkyl, C 4-8 Aryl and C 4-8 Heteroaryl, each of which may be optionally substituted with one or more of -OH, -NH2, -Q, -CQ3, -OCH3, wherein each Q is independently hydrogen, halogen, methyl, phenyl or benzyl; and

[0245] n indicates that the structural unit is repeated, and may be an integer greater than 1.

[0246] 3. The method according to any of the preceding claims, wherein the EBP is a bisphenol-based EBP, such as a bisphenol A-based EBP.

[0247] 4. The method according to any of the preceding claims, wherein the EBP comprises a chemical structural unit of formula (III-c)

[0248]

[0249] The structural unit of formula (III-c) may contain 1 to 4 R3 and R4, wherein R1, R2, R3 and R4 are each independently selected from H, C 1-6 Alkyl, C 1-6 alkenyl, CF3, F, Cl, Br, OH, NO2, NH2, phenyl, or wherein R1 and R2 can together form a C6 cycloalkyl; and wherein n indicates that the structural unit is repeated and can be an integer greater than 1.

[0250] 5. A method according to any preceding claim, wherein the suspension is heated to a temperature between 130°C and 250°C.

[0251] 6. A method according to any preceding claim, wherein the suspension is heated to a temperature between 170°C and 250°C.

[0252] 7. A process according to any preceding claim, wherein the suspension is heated to a temperature between 170°C and 210°C.

[0253] 8. A method according to any preceding claim, wherein the suspension is heated for at least 2 hours, such as at least 4 hours, such as at least 8 hours, such as at least 16 hours, such as at least 24 hours.

[0254] 9. A method according to any of the preceding claims, wherein the suspension is heated for a period of 2 hours to 10 days, such as 2 hours to 4 hours, such as 4 hours to 8 hours, such as 8 hours to 16 hours, such as 16 hours to 24 hours, such as 24 hours to 2 days, such as 2 days to 3 days, such as 3 days to 5 days, such as 5 days to 10 days.

[0255] 10. The method according to any of the preceding claims, wherein the organic solvent is a non-coordinating organic solvent.

[0256] 11. The method according to any of the preceding claims, wherein the organic solvent is an aprotic solvent.

[0257] 12. The method according to any of the preceding claims, wherein the organic solvent is selected from toluene, benzene, xylene, mesitylene, cumene, cymene and mixed xylenes, or any structural isomers thereof.

[0258] 13. The method according to any of the preceding claims, wherein the organic solvent is selected from toluene, xylene and cymene, or a structural isomer of any one thereof.

[0259] 14. The method according to any of the preceding claims, wherein the organic solvent is selected from toluene, p-cymene and o-xylene.

[0260] 15. The method according to any of the preceding claims, wherein the base is a nucleophilic base.

[0261] 16. The method according to any of the preceding claims, wherein the base is an oxygen-containing base or a nitrogen-containing base.

[0262] 17. A method according to any one of items 1 to 16, wherein the base is an oxygen-containing base, such as a hydroxide selected from NaOH, LiOH, KOH, CsOH, RbOH, Ca(OH)2, Sr(OH)2 and Ba(OH)2; or an alcohol salt selected from n-butoxide, tert-butoxide, methanol, ethanol and isopropoxide, including sodium or potassium salts of these alcohol salts.

[0263] 18. The process according to any one of items 1 to 17, wherein the base is selected from NaOH, KOH, NaOBu and NaOtBu.

[0264] 19. A method according to any one of items 1 to 16, wherein the base is a nitrogen-containing base, such as an amide selected from lithium diisopropylamide (LDA), lithium diethylamide (LDEA), sodium amide and lithium bis(trimethylsilyl)amide; or an amine selected from triethylamine, trimethylamine, diethylamine, dimethylamine, pyridine and ammonia.

[0265] 20. The process according to any one of items 1 to 18, wherein the base is not a nitrogen-containing base.

[0266] 21. The method according to any of the preceding claims, wherein the method is carried out in a closed container.

[0267] 22. The method according to any of the preceding claims, wherein the method is carried out at an autogenous pressure of 14.5 to 145 psi.

[0268] 23. The method according to any of the preceding claims, wherein the method is carried out in an inert atmosphere, for example in an atmosphere consisting mainly of nitrogen (N2) or argon (Ar).

[0269] 24. The method according to any one of items 1 to 22, wherein the method is carried out in a non-inert atmosphere, for example using ambient air.

[0270] 25. A method according to any preceding claim, wherein the epoxy-based polymer may be mixed with fibres, for example in fibre-reinforced composites, particularly those in which the fibres are glass or carbon fibres.

[0271] 26. The method according to any of the preceding claims, wherein the EBP is a powder.

[0272] 27. The method according to item 26, wherein the size distribution of the EBP powder is characterized by D 90 Less than 1000 μm, for example less than 900 μm, for example less than 800 μm, for example less than 700 μm, for example less than 600 μm, for example less than 500 μm, for example less than 400 μm, for example less than 300 μm, for example less than 200 μm, for example less than 100 μm.

[0273] 28. The method according to any one of items 26 to 27, wherein the size distribution of the EBP powder is characterized by D 90 Less than 500 μm, for example less than 400 μm.

[0274] 29. The method according to any one of items 26 to 28, wherein the size distribution of the EBP powder is characterized by D 90 It is 100μm to 1000μm, for example 100μm to 200μm, for example 200μm to 275μm, for example 275μm to 325μm, for example 325μm to 350μm, for example 350μm to 375μm, for example 375μm to 400μm, for example 400μm to 425μm, for example 425μm to 500μm, for example 500μm to 600μm, for example 600μm to 700μm, for example 700μm to 800μm, for example 800μm to 1000μm.

[0275] 30. The method according to any one of items 26 to 29, wherein the size distribution of the EBP powder is characterized by D 90 200 μm to 500 μm, for example, 300 μm to 400 μm.

[0276] 31. The method according to any one of items 26 to 30, wherein the size distribution of the EBP powder is characterized by D 50 Less than 300 μm, such as less than 250 μm, such as less than 225 μm, such as less than 200 μm, such as less than 175 μm, such as less than 150 μm.

[0277] 32. The method according to any one of items 26 to 31, wherein the size distribution of the EBP powder is characterized by D 50 Less than 225 μm, for example less than 175 μm.

[0278] 33. The method according to any one of items 26 to 32, wherein the size distribution of the EBP powder is characterized by D 50 50 μm to 300 μm, for example 50 μm to 75 μm, for example 75 μm to 100 μm, for example 100 μm to 125 μm, for example 125 μm to 150 μm, for example 150 μm to 175 μm, for example 175 μm to 250 μm, for example 250 μm to 300 μm.

[0279] 34. The method according to any one of items 26 to 33, wherein the size distribution of the EBP powder is characterized by D 50 75 μm to 200 μm, for example, 100 μm to 175 μm.

[0280] 35. A method according to any preceding claim, wherein the method does not comprise or use a metal catalyst.

[0281] Project 2

[0282] 1. A method for deconvoluting an epoxy-based polymer (EBP), the method comprising providing the EBP, and further comprising the step of contacting the EBP with a solvent system comprising at least one organic solvent and a base to form a suspension, wherein the base is added in an amount equivalent to 20% to 100% by weight of the EBP.

[0283] 2. The method according to the preceding item, wherein the EBP comprises a chemical structural unit of formula (III-a)

[0284]

[0285] in,

[0286] X1 is selected from H, R or -C(=O)R, wherein R can be C 1-6 Alkyl, C 1-6 Heteroalkyl, C 1-6 Alkoxy, C 1-6 Allyl, C 1-6 Heteroallyl, C 4-8 Cycloalkyl, C 4-8 Heterocycloalkyl, C 4-8 Aryl and C 4-8 Heteroaryl, each of which may be optionally substituted with one or more of -OH, -NH2, -L, -CL3, -OCH3, wherein L is halogen;

[0287] X2 Selected from C 4-8 Cycloalkyl, C 4-8 Heterocycloalkyl, C 4-8 Aryl and C 4-8 Heteroaryl, each of which may be optionally substituted with one or more of -OH, -NH2, -Q, -CQ3, -OCH3, wherein each Q is independently hydrogen, halogen, methyl, or benzyl; and

[0288] n indicates that the structural unit is repeated, and may be an integer greater than 1.

[0289] 3. The method according to any of the preceding claims, wherein the EBP is a bisphenol-based EBP, such as a bisphenol A-based EBP.

[0290] 4. The method according to any of the preceding claims, wherein the EBP comprises a chemical structural unit of formula (III-c)

[0291]

[0292] The structural unit of formula (III-c) may contain 1 to 4 R3 and R4, wherein R1, R2, R3 and R4 are each independently selected from H, C 1-6 Alkyl, C 1-6 alkenyl, CF3, F, Cl, Br, OH, NO2, NH2, phenyl, or wherein R1 and R2 can together form a C6 cycloalkyl; and wherein n indicates that the structural unit is repeated and can be an integer greater than 1.

[0293] 5. A process according to any preceding claim, wherein the suspension is heated to a temperature of at least 150°C for at least 16 hours.

[0294] 6. A process according to any preceding claim, wherein the suspension is heated to a temperature between 170°C and 210°C for at least 16 hours.

[0295] 7. The method according to any of the preceding claims, wherein the organic solvent is a non-coordinating aprotic organic solvent having a boiling point above 100°C.

[0296] 8. The method according to any of the preceding claims, wherein the organic solvent is selected from toluene, benzene, xylene, mesitylene, isopropylbenzene, cymene and mixed xylenes, or a structural isomer of any one of them.

[0297] 9. The method according to any of the preceding claims, wherein the base is selected from NaOH, KOH, NaOBu and NaOtBu.

[0298] 10. The method according to any of the preceding claims, wherein the method is carried out in a non-inert atmosphere, for example using ambient air.

[0299] 11. The method according to any of the preceding claims, further comprising the step of pre-treating the epoxy-based polymer.

[0300] 12. A method according to any preceding claim, wherein the epoxy-based polymer may be mixed with fibres, for example in fibre-reinforced composites, particularly those in which the fibres are glass or carbon fibres.

[0301] 13. The method according to any of the preceding claims, wherein the EBP is a powder.

[0302] 14. The method according to any of the preceding claims, wherein the method does not comprise or use a metal catalyst.

Claims

1. A method for deconvolution of an epoxy-based polymer (EBP), the method comprising the steps of: a. Provide EBP, b. contacting the EBP with a solvent system comprising at least one aprotic non-polar organic solvent and an oxygen-containing base to form a suspension, and c. heating the suspension to a temperature of at least 130° C. for at least 2 hours, thereby releasing the monomers of EBP into the suspension, The base is added in an amount equivalent to 20% to 100% by weight of the EBP, and the method does not include or use a catalyst.

2. The method of the preceding claim, wherein the EBP is derived from bisphenol diglycidyl ether.

3. The method according to any one of the preceding claims, wherein the EBP comprises a chemical structural unit of formula (III-a) in, X1 is selected from H, R or -C(=O)R, wherein R can be C 1-6 Alkyl, C 1-6 Heteroalkyl, C 1-6 Alkoxy, C 1-6 Allyl, C 1-6 Heteroallyl, C 4-8 Cycloalkyl, C 4-8 Heterocycloalkyl, C 4-8 Aryl and C 4-8 Heteroaryl, each of which may be optionally substituted with one or more of -OH, -NH2, -L, -CL3, -OCH3, wherein L is halogen; X2 Selected from C 4-8 Cycloalkyl, C 4-8 Heterocycloalkyl, C 4-8 Aryl and C 4-8 Heteroaryl, each of which may be optionally substituted with one or more of -OH, -NH2, -Q, -CQ3, -OCH3, wherein each Q is independently hydrogen, halogen, methyl, phenyl or benzyl; and n indicates that the structural unit is repeated, and may be an integer greater than 1. The method according to claim 3 , wherein X 1 is H.

5. The method according to any one of claims 3 to 4, wherein X2 is C 4-8 Aryl, preferably aromatic C6 aryl such as benzene, is optionally substituted by one or more of -OH, -NH2, -Q, -CQ3, -OCH3, wherein each Q is independently hydrogen, halogen, methyl, phenyl or benzyl.

6. The method according to any one of claims 3 to 5, wherein X2 is phenyl.

7. The method of claim 1, wherein the EBP is an amine-cured epoxy resin.

8. The method of claim 7, wherein the EBP comprises one or more cross-linking agents and / or hardeners selected from the group consisting of polyamide resins, poly(oxypropylene) diamines, 3-aminomethyl-3,5,5-trimethylcyclohexylamine, triethylenetetramine, tetraethylenepentamine, and amine-terminated trimethylolpropane tris[poly(propylene glycol)] ether (T-403).

9. The method according to any one of the preceding claims, wherein the EBP comprises a chemical structural unit of formula (III-a(i)): in, X1 is selected from H, R or -C(=O)R, X2 Selected from C 4-8 Cycloalkyl, C 4-8 Heterocycloalkyl, C 4-8 Aryl and C 4-8 Heteroaryl, each of which may be optionally substituted by one or more of -OH, -NH2, -Q, -CQ3, -OCH3, wherein each Q is independently hydrogen, halogen, methyl, phenyl or benzyl, X3 is selected from CR2, NZ, O and S, Where R can be C 1-6 Alkyl, C 1-6 Heteroalkyl, C 1-6 Alkoxy, C 1-6 Allyl, C 1-6 Heteroallyl, C 4-8 Cycloalkyl, C 4-8 Heterocycloalkyl, C 4-8 Aryl and C 4-8 Heteroaryl, each of which may be optionally substituted by one or more of -OH, -NH2, -L, -CL3, -OCH3, wherein L is halogen, wherein NZ represents an amine-based crosslinker and / or hardener selected from the group consisting of polyamide resins, poly(oxypropylene)diamines, 3-aminomethyl-3,5,5-trimethylcyclohexylamine, triethylenetetramine, tetraethylenepentamine, and amine-terminated trimethylolpropane tris[poly(propylene glycol)]ether (T-403), and Wherein n represents that the structural unit is repeated, and can be an integer greater than 1.

10. The method of claim 9, wherein X1 is H.

11. The method according to any one of claims 9 to 10, wherein X2 is C 4-8 Aryl, preferably aromatic C6 aryl such as benzene, which is optionally substituted by one or more of -OH, -NH2, -L, -CL3, -OCH3, wherein L is halogen.

12. The method according to any one of claims 9 to 11, wherein X3 is selected from O and NZ.

13. The method according to any one of the preceding claims, wherein the EBP comprises a chemical structural unit of formula (III-da): wherein R5 is selected to be O or NZ, wherein NZ represents an amine-based crosslinker and / or hardener selected from polyamide resin, poly(oxypropylene)diamine, 3-aminomethyl-3,5,5-trimethylcyclohexylamine, triethylenetetramine, tetraethylenepentamine, and amine-terminated trimethylolpropane tris[poly(propylene glycol)]ether (T-403), And wherein Ar represents an aromatic ring, such as phenyl or naphthyl, preferably phenyl.

14. The method according to claim 13, wherein the aromatic ring Ar may be substituted.

15. The method according to any one of the preceding claims, wherein the EBP is a bisphenol-based EBP, such as a bisphenol A-based EBP.

16. A method according to any one of the preceding claims, wherein the monomer released into the suspension is a bisphenol-based monomer.

17. A method according to any one of the preceding claims, wherein the monomer released into the suspension is a bisphenol A based monomer.

18. A method according to any one of the preceding claims, wherein the monomer released into the suspension is bisphenol A.

19. The process according to any one of the preceding claims, wherein the process allows for direct separation and isolation of bisphenol A based monomers.

20. The method according to any one of the preceding claims, wherein the EBP comprises a chemical structural unit of formula (III-ca): The structural unit of formula (III-ca) may contain 1 to 4 R3 and R4, wherein R1, R2, R3 and R4 are each independently selected from H, C 1-6 Alkyl, C 1-6 alkenyl, CF3, F, Cl, Br, OH, NO2, NH2, phenyl, or wherein R1 and R2 can together form a C6 cycloalkyl, and wherein R5 is selected to be O or NZ, wherein NZ represents an amine-based crosslinker and / or hardener selected from polyamide resins, poly(oxypropylene)diamine, 3-aminomethyl-3,5,5-trimethylcyclohexylamine, triethylenetetramine, tetraethylenepentamine and amine-terminated trimethylolpropane tri[poly(propylene glycol)] ether (T-403).

21. A method according to any one of the preceding claims, wherein the suspension is heated to a temperature between 130°C and 250°C.

22. A method according to any one of the preceding claims, wherein the suspension is heated to a temperature between 170°C and 250°C.

23. A method according to any one of the preceding claims, wherein the suspension is heated to a temperature between 170°C and 210°C.

24. A method according to any one of the preceding claims, wherein the suspension is heated for at least 2 hours, such as at least 4 hours, such as at least 8 hours, such as at least 16 hours, such as at least 24 hours.

25. The method according to any one of the preceding claims, wherein the suspension is heated for a period of 2 hours to 10 days, such as 2 hours to 4 hours, such as 4 hours to 8 hours, such as 8 hours to 16 hours, such as 16 hours to 24 hours, such as 24 hours to 2 days, such as 2 days to 3 days, such as 3 days to 5 days, such as 5 days to 10 days.

26. The process according to any one of the preceding claims, wherein the organic solvent is selected from toluene, benzene, xylene, mesitylene, cumene, cymene and mixed xylenes, or structural isomers of any one thereof.

27. A process according to any one of the preceding claims, wherein the organic solvent is selected from toluene, xylene and cymene, or a structural isomer of any one thereof.

28. A process according to any one of the preceding claims, wherein the organic solvent is selected from toluene, p-cymene and o-xylene.

29. A process according to any one of the preceding claims, wherein the oxygen-containing base is a hydroxide selected from the group consisting of NaOH, LiOH, KOH, CsOH, RbOH, Ca(OH)2, Sr(OH)2 and Ba(OH)2; or an alkoxide selected from the group consisting of n-butoxide, tert-butoxide, methoxide, ethoxide and isopropoxide, including the sodium or potassium salts of these alkoxides.

30. The process according to any one of the preceding claims, wherein the base is selected from NaOH, KOH, NaOBu and NaOtBu.

31. A method according to any one of the preceding claims, wherein the base is a nucleophilic base.

32. A process according to any one of the preceding claims, wherein the base is not a nitrogenous base.

33. A process according to any one of the preceding claims, wherein the process is carried out in a closed vessel under autogenous pressure.

34. The process of any one of the preceding claims, wherein the process is carried out in a closed vessel at an autogenous pressure of 14.5 to 145 psi.

35. The method according to any one of the preceding claims, wherein the method is carried out in an inert atmosphere, for example in an atmosphere consisting mainly of nitrogen (N2) or argon (Ar).

36. A method according to any one of claims 1 to 34, wherein the method is carried out in a non-inert atmosphere, such as using ambient air.

37. The method according to any one of claims 1 to 32, wherein the method is carried out in an open container.

38. The process according to any one of the preceding claims, wherein the process is a one-pot reaction.

39. A method according to any preceding claim, wherein the epoxy-based polymer may be mixed with fibres, for example in a fibre reinforced composite material, in particular a composite material wherein the fibres are glass fibres or carbon fibres.

40. The method of any preceding claim, wherein the EBP is a powder.

41. The method of claim 40, wherein the size distribution of the EBP powder is characterized by D 90 Less than 1000 μm, for example less than 900 μm, for example less than 800 μm, for example less than 700 μm, for example less than 600 μm, for example less than 500 μm, for example less than 400 μm, for example less than 300 μm, for example less than 200 μm, for example less than 100 μm.

42. The method of any one of claims 40 to 41, wherein the size distribution of the EBP powder is characterized by D 90 Less than 500 μm, for example less than 400 μm.

43. The method of any one of claims 40 to 42, wherein the size distribution of the EBP powder is characterized by D 90 It is 100μm to 1000μm, for example 100μm to 200μm, for example 200μm to 275μm, for example 275μm to 325μm, for example 325μm to 350μm, for example 350μm to 375μm, for example 375μm to 400μm, for example 400μm to 425μm, for example 425μm to 500μm, for example 500μm to 600μm, for example 600μm to 700μm, for example 700μm to 800μm, for example 800μm to 1000μm.

44. The method of any one of claims 40 to 43, wherein the size distribution of the EBP powder is characterized by D 90 200 μm to 500 μm, for example, 300 μm to 400 μm.

45. The method of any one of claims 40 to 44, wherein the size distribution of the EBP powder is characterized by D 50 Less than 300 μm, such as less than 250 μm, such as less than 225 μm, such as less than 200 μm, such as less than 175 μm, such as less than 150 μm.

46. ​​The method of any one of claims 40 to 45, wherein the size distribution of the EBP powder is characterized by D 50 Less than 225 μm, for example less than 175 μm.

47. The method of any one of claims 40 to 46, wherein the size distribution of the EBP powder is characterized by D 50 50 μm to 300 μm, for example 50 μm to 75 μm, for example 75 μm to 100 μm, for example 100 μm to 125 μm, for example 125 μm to 150 μm, for example 150 μm to 175 μm, for example 175 μm to 250 μm, for example 250 μm to 300 μm.

48. The method of any one of claims 40 to 47, wherein the size distribution of the EBP powder is characterized by D 50 75 μm to 200 μm, for example, 100 μm to 175 μm.

49. The method of any preceding claim, wherein the method does not comprise or use hydrogen peroxide.

50. The method of any one of the preceding claims, wherein the method does not comprise or use ascorbic acid.

51. The method of any preceding claim, wherein the method does not comprise or use hydrogen peroxide or ascorbic acid.

52. The method of any one of the preceding claims, wherein the EBP is not chemically treated prior to the step of contacting the EBP with a suspension comprising at least one aprotic non-polar organic solvent and an oxygen-containing base.

53. A method according to any preceding claim, wherein steps a, b and c are performed sequentially in the order indicated.

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