Non-isocyanate polyurea polymer and recycling method therefor

Abstract

The present invention relates to a non-isocyanate polyurea polymer and a recycling method therefor. The polyurea polymer has faster reactivity than conventional polyurea polymers, is environmentally friendly due to not using isocyanate, and can minimize the use of toxic substances. By having various covalent bonds to form a non-isocyanate-based dynamic covalent bond network, various recycling such as reshaping, chemical recycling, and upcycling is possible, and thus the problem of recyclability of thermosetting polymers can be solved. In addition, the polyurea polymer has both mechanical stability and thermal stability, and thus can be widely applied in various industrial fields.

Description

Non-isocyanate polyurea polymer and recycling method thereof

[0001] The present invention relates to a non-isocyanate polyurea polymer and a method for recycling the same.

[0002] Since the Industrial Revolution, the increase in petroleum-based waste has had a serious negative impact on the environment. In particular, although thermosetting polymers play a crucial role in various industrial fields that distinguishes them from thermoplastics by enhancing mechanical rigidity, chemical inertness, and thermal stability, their superior mechanical, chemical, and thermal properties make recycling and remodeling difficult, further exacerbating the waste problem.

[0003] The disposal methods of thermosetting polymers primarily rely on environmentally harmful incineration or landfilling, which poses a significant problem from the perspective of sustainable development. To address this issue, there is a growing need for the development of non-toxic, sustainable, and eco-friendly materials.

[0004] Dynamic bonding chemistry is attracting attention as a solution to these problems. Based on chemical bonds that can be reversibly formed or decomposed under specific conditions, dynamic bonding chemistry enables polymer materials to undergo structural changes in response to specific stimuli. Dynamic covalent networks (CANs) impart properties such as self-healing, recyclability, and conformational change to materials through transesterification and carbamate exchange, and can enhance the recyclability of thermosetting polymers.

[0005] Among the many shared adaptation networks (CANs), a recycling technology using isocyanates as a curing agent and Hindered Urea Bond (HUB) has been introduced. However, isocyanates are substances derived from toxic compounds such as phosgene, and they have a fatal disadvantage of not being suitable for sustainable recycling processes as they pose a significant risk to the environment and health.

[0006] To address this, polyurethanes that do not use isocyanates (non-isocyanate polyurethanes (NIPUs)) have been studied as an eco-friendly alternative, but there is still a problem that the reactivity of recycled carbonates and amines for manufacturing non-isocyanate polyurethanes is significantly lower than that of conventional methods using isocyanates.

[0007] Accordingly, in order to develop sustainable materials that overcome the limitations of existing petroleum-based polymers, there is an urgent need for research and development on methods for manufacturing and recycling non-isocyanate-based polymers that are recyclable, exhibit excellent properties even after recycling, provide high reactivity, and are environmentally friendly.

[0008] The object of the present invention is to provide a non-isocyanate polyurea polymer with excellent reactivity and a method for manufacturing the same.

[0009] In addition, another objective of the present invention is to provide a chemical and physical recycling method using the polyurea polymer and an upcycling method using the same.

[0010] In order to achieve the above objective, the inventors continuously researched to develop a non-isocyanate polyurea polymer that is reformable and chemically recyclable, possessing sustainable eco-friendliness, and excellent reactivity. As a result, they discovered that when a polyurea polymer is used from a polymerizable composition containing a hindered urea monomer and a multifunctional monomer of a specific structure, it can form a dynamic covalent bond network by having one or more covalent bonds among a hindered urea bond, a thiol-Michael bond, and an ester bond, thereby having excellent thermal and mechanical properties, and that reformable, chemically recyclable, and upcyclable polymers are all possible, and that excellent mechanical properties can be maintained even after such recycling, thus completing the present invention.

[0011] The present invention provides a polyurea polymer prepared from a polymerizable composition comprising a hindered urea monomer and a polyfunctional monomer represented by the following chemical formula 1.

[0012] [Chemical Formula 1]

[0013] L-(X)n

[0014] In the above chemical formula 1,

[0015] L is an n-valent organic group, and

[0016] n is an integer from 2 to 5, and

[0017] X is And,

[0018] The above A is a heteroaromatic, cycloaliphatic, or heterocycloaliphatic ring, and

[0019] The above Y is a substituted or unsubstituted C1-30 alkylene or C1-30 heteroalkylene.

[0020] According to one embodiment of the present invention, the hindered urea monomer may be represented by the following chemical formula 2.

[0021] [Chemical Formula 2]

[0022]

[0023] In the above chemical formula 2,

[0024] A1 and A2 are independently heteroaromatic, cycloaliphatic, or heterocycloaliphatic rings, and

[0025] Y1 and Y2 are independently substituted or unsubstituted C1-30 alkylenes or C1-30 heteroalkylenes, and

[0026] L is a substituted or unsubstituted C1-30 alkylene or C1-30 heteroalkylene.

[0027] According to one embodiment of the present invention, the hindered urea monomer may be represented by the following chemical formula 3.

[0028] [Chemical Formula 3]

[0029]

[0030] In the above chemical formula 3,

[0031] Y1 and Y2 are independently substituted or unsubstituted C1-7 alkylenes, and

[0032] L is a substituted or unsubstituted C1-15 alkylene.

[0033] According to one embodiment of the present invention, the polyfunctional monomer may contain three or more functional groups capable of reacting with thiol groups.

[0034] According to one embodiment of the present invention, the polyfunctional monomer may contain one or more selected from the group consisting of epoxy, acrylic, vinyl, alkyl halide, aldehyde, ketone, carbonyl, carboxylic acid, ester, maleimide, and alkene.

[0035] According to one embodiment of the present invention, the polyfunctional monomer may be represented by the following chemical formula 4.

[0036] [Chemical Formula 4]

[0037]

[0038] In the above chemical formula 4,

[0039] R 41 is a C1-15 alkyl, and

[0040] L 41 to L 43 They are independently C1-15 alkylenes, and

[0041] X 41 To X 43 They are independently epoxy, acrylic, vinyl, alkyl halide, aldehyde, or carboxylic acid.

[0042] According to one embodiment of the present invention, the hindered urea monomer to the polyfunctional monomer may satisfy a molar ratio of 0.5 to 1.5:1.

[0043] According to one embodiment of the present invention, the hindered urea monomer and the polyfunctional monomer may not contain isocyanate groups.

[0044] According to one embodiment of the present invention, the polyurea polymer may comprise the structure of the following chemical formula 5.

[0045] [Chemical Formula 5]

[0046]

[0047] In the above chemical formula 5,

[0048] A1 and A2 are independently heteroaromatic, cycloaliphatic, or heterocycloaliphatic rings, and

[0049] Y1 and Y2 are independently substituted or unsubstituted C1-30 alkylenes or C1-30 heteroalkylenes, and

[0050] L is a substituted or unsubstituted C1-30 alkylene or C1-30 heteroalkylene, and

[0051] R 41 is a C1-15 alkyl, and

[0052] L 41 to L 43 They are independently C1-15 alkylenes and

[0053] L5 is or And,

[0054] -* is a connector.

[0055] According to one embodiment of the present invention, the polyurea polymer may have a gel content of 95% or more.

[0056] According to one embodiment of the present invention, the polyurea polymer may have a glass transition temperature of -10 to 50°C as measured by DSC.

[0057] According to one embodiment of the present invention, the glass transition temperature measured by DSC after performing cutting and heat pressing three times on the polyurea polymer at 130°C for 30 minutes under a pressure of 10 MPa may be within the range of the initial glass transition temperature ± 10°C before the process.

[0058] According to one embodiment of the present invention, the polyurea polymer may have an activation energy of 200 kJ / mol or less at 120°C.

[0059] According to one embodiment of the present invention, the polyurea polymer may comprise a dynamic covalent bond network.

[0060] According to one embodiment of the present invention, the polyurea polymer may comprise one or more bonds selected from hindered urea bonds, thiol-Michael bonds, and ester bonds.

[0061] The present invention can provide a chemical recycling method for a polyurea polymer comprising the step of dissolving the above-described polyurea polymer in a solvent and depolymerizing it into an oligomer.

[0062] According to one embodiment of the present invention, the solvent may be an aprotic solvent or an alcohol solvent.

[0063] According to one embodiment of the present invention, the solvent may further comprise a catalyst.

[0064] According to one embodiment of the present invention, the catalyst may be any one or more combinations selected from the group consisting of 1,8-diazabicyclo[5.4.0]undecene (DBU), 1,4-diazabicyclo[2.2.2]octane (DABCO), triethylamine, and 1,5-diazabicyclo[4.3.0]nonene (DBN).

[0065] According to one embodiment of the present invention, a step of curing the oligomer and the polymerizable monomer may be further performed.

[0066] According to one embodiment of the present invention, the depolymerization may be performed at 120°C or lower.

[0067] The present invention can provide a method for upcycling a polyurea polymer, comprising the steps of: depolymerizing the above-described polyurea polymer in the presence of a solvent and a catalyst to obtain an oligomer; and reacting the oligomer with a polymer.

[0068] According to one embodiment of the present invention, the solvent may be a polyol.

[0069] According to one embodiment of the present invention, the polymer may contain any one functional group selected from the group consisting of epoxide, acyl halide, carboxylic acid, isocyanate, carbonate, anhydride, and aldehyde.

[0070] The present invention relates to a polyurea polymer prepared from a polymerizable composition comprising a monomer containing a thiol group and hindered urea and a polyfunctional monomer. The polyurea polymer has faster reactivity than conventional polymers, is environmentally friendly as it does not use isocyanates, and can minimize the use of toxic substances. Furthermore, it possesses one or more covalent bonds among hindered urea bonds, thiol-Michael bonds, and ester bonds, thereby forming a non-isocyanate-based dynamic covalent bond network. The polyurea polymer exhibits excellent mechanical properties such as tensile strength, Young's modulus, and elongation, and demonstrates superior energy loss characteristics. The polyurea polymer exhibiting these properties possesses both mechanical and thermal stability and can therefore be widely applied in various industrial fields.

[0071] Furthermore, since the aforementioned polyurea polymer allows for various recycling methods such as remolding, chemical recycling, and upcycling, it can resolve the recyclability issues of thermosetting polymers. Additionally, thanks to reprocessability utilizing dynamic bonding, it is possible to develop environmentally friendly and sustainable materials and pursue diverse industrial applications while maintaining the polymer's performance.

[0072] FIG. 1a is a schematic diagram briefly illustrating a method for manufacturing a polyurea polymer according to one embodiment of the present invention, and FIG. 1b is a schematic diagram briefly illustrating a method for reshaping, chemically recycling, and upcycling a polyurea polymer according to one embodiment.

[0073] Figure 2 is the FT-IR spectrum for the polyurea polymers of Examples 1 and 2 of the present invention.

[0074] Figure 3 is an SS curve (stress-strain curve) of a polyurea polymer film prepared according to Examples 1 and 2 of the present invention.

[0075] Figure 4 is a graph of the storage modulus and tan δ analyzed by DMA of polyurea polymers prepared according to Examples 1 and 2 of the present invention.

[0076] Figure 5 is the NMR spectrum of an oligomer containing piperidine terminal groups prepared by depolymerizing hindered urea bonds of the polyurea polymer of Example 1 of the present invention.

[0077] FIG. 6 is a schematic diagram briefly illustrating the chemical recycling of a polyurea polymer according to one embodiment. FIG. 6 (a) shows the chemical recycling of the polymer using hindered urea bonds and thiol-Michael bonds of the polymer of Example 1, FIG. 6 (b) shows the chemical recycling of the polymer using hindered urea bonds of the polymer of Example 2, and FIG. 6 (c) shows the chemical recycling and upcycling using ester bonds of the polymer of Example 1.

[0078] Figure 7 is the FT-IR spectrum of the polymer of Example 2 (TZ-DPP-TE) and the polyurea polymer recycled using hindered urea bonds (Recycled_HU).

[0079] Figure 8 is the FT-IR spectrum of the polymer of Example 1 (TZ-DPP-TA), the polyurea polymer recycled using hindered urea bonds (Recycled_HU), and the polyurea polymer recycled using thiol-Michael bonds (Recycled_TM).

[0080] Figure 9 is the NMR spectrum obtained by NMR analysis of the TZ-DPP of Preparation Example 2 and the dihydroxyl oligomer (TZ-DPP-EG).

[0081] Figure 10 is the FT-IR spectrum of TZ-DPP-EG-PAA according to Evaluation Example 4.

[0082] The present invention will be described in more detail below through specific examples or embodiments, including the attached drawings. However, the following embodiments are for reference only to explain the present invention in detail, and the present invention is not limited thereto and can be implemented in various forms.

[0083] Furthermore, unless otherwise defined, all technical and scientific terms have the same meaning as generally understood by one of the art to which the present invention pertains. The terms used in the description herein are merely for the purpose of effectively describing specific embodiments and are not intended to limit the present invention.

[0084] In the present invention, when a part is described as "comprising" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0085] Additionally, the singular form used in the specification and the appended claims may be intended to include the plural form unless specifically indicated otherwise in the context.

[0086] Unless otherwise defined, technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art to which this invention pertains, and descriptions of known functions and configurations that could unnecessarily obscure the essence of the invention are omitted in the following description and accompanying drawings.

[0087] Additionally, units used herein without special mention are based on weight, for example, units of % or ratio mean weight % or weight ratio, and weight % means the weight percentage of any one component of the total composition that occupies the composition, unless otherwise defined.

[0088] Additionally, the numerical ranges used in this specification may include lower and upper limits and all values ​​within the range, increments logically derived from the form and width of the defined range, all of which are limited values, and all possible combinations of upper and lower limits of numerical ranges defined in different forms. Unless otherwise specifically defined in the specification of this invention, values ​​outside the numerical range that may occur due to experimental error or rounding of values ​​are also included in the defined numerical range.

[0089] Furthermore, the term "self-healing" in this specification refers, in a broad sense, to the ability of damaged material to heal (recover or restore) itself automatically and autonomously to its original state under specific conditions, and in a narrow sense, to the ability to restore damage caused by external forces to its original state to some extent.

[0090] Additionally, the term "Dynamic Covalent Bond Network" in this specification refers to a polymer network structure in which the formation and dissociation of covalent bonds are reversibly repeated by external stimuli (temperature, light, chemicals, etc.), and may have a meaning commonly or academically accepted.

[0091] In addition, the term "Hindered Urea Bond (HUB)" in this specification refers to a urea bond comprising the following structure formed by the reaction of an amine with steric hindrance with an isocyanate, carbamate compound, or thiolcarbamate compound. Due to the steric hindrance, the bond has dynamic characteristics, meaning it can dissociate and recombine depending on temperature or external stimuli, which means the bond can be temporarily broken and re-bonded in a polymer network.

[0092] [structure]

[0093]

[0094] The above A is a heteroaromatic, cycloaliphatic, or heterocycloaliphatic ring.

[0095] In addition, the term "Thiol-Michael bond" in this specification refers to a bond formed by a thiol-ene reaction, which is a thiol-Michael addition reaction. Since said bond is reversible under specific conditions, it can possess dynamic properties, thereby improving the recyclability, self-healing, and reprocessability of polymer materials.

[0096] In addition, the term "ester bond" in this specification refers to a conventional -(C=O)O- bond, and can be reversibly transesterified under specific conditions in the presence of amines, alcohols, glycols, etc., thereby having dynamic properties, which can improve the recyclability, self-healing, and reprocessability of polymer materials.

[0097] Additionally, the term "chemical recycling" in this specification refers to the process of chemically breaking down the molecular structure of a polymer material, such as a polyurea polymer, to convert it into the original monomer or other chemical components.

[0098] Furthermore, the term "upcycling" in this specification refers to a system that chemically decomposes and reconfigures polymeric materials, such as polyurea polymers, to create a new form of material that enhances the functional value or applicability of the original material. Such upcycling is an important strategy that promotes the efficient use of resources and reduces environmental impact by converting waste resources into valuable new products, while simultaneously increasing sustainability.

[0099] Additionally, the term "substituted" in this specification means that a hydrogen atom of the substituted portion (e.g., alkyl) is replaced by a substituent. Unless otherwise noted with respect to the substituents, any substituent of the present invention may be hydroxy, halogen, nitro, cyano, amino, secondary amine, carboxyl, carboxylate, C1-7 Alkyl, C 1-7 Alkenyl, C 1-7 Haloalkyl, C 1-7 Alkoxy and C 1-7 It may include alkoxycarbonyls, etc.

[0100] Additionally, the term "alkyl" in this specification includes both linear (straight-chain) and branched forms, and may have 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms.

[0101] Additionally, the term "heteroalkyl" in this specification means an alkyl having one bonding position containing one or more heteroatoms, and the meaning of hetero is that the carbon of the alkyl is substituted with one or more heteroatoms selected from B, O, N, C(=O), P, P(=O), S, S(=O)2 and Si atoms.

[0102] The "alkylene" and "heteroalkylene" described in the present invention each refer to a divalent organic radical derived by the removal of one hydrogen from "alkyl" and "heteroalkyl," and follow the respective definitions of alkyl and heteroalkyl.

[0103] In addition, the term "heterocyclic" in this specification means a non-aromatic monocyclic or multicyclic ring system having 3 to 10 carbon atoms, wherein any one of the carbons in the ring is substituted with one or more heteroatoms selected from B, O, N, C(=O), P, P(=O), S, S(=O)2 and Si atoms.

[0104] Additionally, the term "hetero-aromatic" in this specification means that any one of the carbons forming the aromatic ring is substituted with one or more heteroatoms selected from B, O, N, C(=O), P, P(=O), S, S(=O)2, and Si atoms.

[0105] Additionally, the term "oligomer" in this specification refers to a polymer of relatively low molecular weight produced by depolymerizing a polyurea polymer, which is a thermosetting polymer according to one embodiment.

[0106] Hereinafter, a polyurea polymer according to one embodiment of the present invention and a method for manufacturing the same will be described in more detail.

[0107] The present invention provides a polyurea polymer prepared from a polymerizable composition comprising a hindered urea monomer and a polyfunctional monomer represented by the following chemical formula 1.

[0108] [Chemical Formula 1]

[0109] L-(X)n

[0110] In the above chemical formula 1,

[0111] L is an n-valent organic group, and

[0112] n is an integer from 2 to 5, and

[0113] X is And,

[0114] The above A is a heteroaromatic, cycloaliphatic, or heterocycloaliphatic ring, and

[0115] The above Y is a substituted or unsubstituted C1-30 alkylene or C1-30 heteroalkylene.

[0116] According to one embodiment of the present invention, when n in Chemical Formula 1 is 2 or more, each X may be the same or different from each other.

[0117] According to one embodiment of the present invention, n in Chemical Formula 1 may be 2 or 3.

[0118] According to one embodiment of the present invention, in X of Formula 1, A may be a cycloaliphatic ring, and Y may be an unsubstituted C1-30 alkylene, C1-15 alkylene, or C1-7 alkylene.

[0119] According to one embodiment of the present invention, the hindered urea monomer may be represented by the following chemical formula 2.

[0120] [Chemical Formula 2]

[0121]

[0122] In the above chemical formula 2,

[0123] A1 and A2 are independently heteroaromatic, cycloaliphatic, or heterocycloaliphatic rings, and

[0124] Y1 and Y2 are independently substituted or unsubstituted C1-30 alkylenes or C1-30 heteroalkylenes, and

[0125] L is a substituted or unsubstituted C1-30 alkylene or C1-30 heteroalkylene.

[0126] According to one embodiment of the present invention, in the formula 2, A1 and A2 may independently be a heterocyclic ring, a nitrogen atom-containing heterocyclic ring, a nitrogen atom-containing C3-30 heterocyclic ring, or a nitrogen atom-containing C4-15 heterocyclic ring.

[0127] According to one embodiment of the present invention, Y1 and Y2 in Formula 2 may be independently unsubstituted C1-30 alkylene, C1-15 alkylene, or C1-7 alkylene.

[0128] According to one embodiment of the present invention, the hindered urea monomer may be represented by the following chemical formula 3.

[0129] [Chemical Formula 3]

[0130]

[0131] In the above chemical formula 3,

[0132] Y1 and Y2 are independently substituted or unsubstituted C1-7 alkylenes, and

[0133] L is a substituted or unsubstituted C1-15 alkylene.

[0134] According to one embodiment of the present invention, in the formula 3, Y1 and Y2 may be independently methylene, ethylene, or propylene.

[0135] According to one embodiment of the present invention, L in Formula 3 may be an unsubstituted C1-7 alkylene, methylene, ethylene, propylene, or butylene.

[0136] According to one embodiment of the present invention, the polyfunctional monomer may contain three or more, four or five functional groups capable of reacting with thiol groups. The functional groups may be one or more selected from the group consisting of epoxy, acrylic, vinyl, alkyl halide, aldehyde, ketone, carbonyl, carboxylic acid, ester, maleimide, and alkene.

[0137] According to one embodiment of the present invention, the polyfunctional monomer may contain one or more functional groups selected from the group consisting of epoxy, acrylic, vinyl, alkyl halide, aldehyde, ketone, carbonyl, carboxylic acid, ester, maleimide, and alkene, and specifically may contain one or more functional groups selected from the group consisting of epoxy, acrylic, vinyl, alkyl halide, aldehyde, and carboxylic acid, or one or more selected from the group consisting of epoxy, acrylic, vinyl, etc.

[0138] According to one embodiment of the present invention, the polyfunctional monomer may be represented by the following chemical formula 4.

[0139] [Chemical Formula 4]

[0140]

[0141] In the above chemical formula 4,

[0142] R 41 is a C1-15 alkyl, and

[0143] L 41 to L 43They are independently C1-15 alkylenes, and

[0144] X 41 To X 43 They are independently epoxy, acrylic, vinyl, alkyl halide, aldehyde, or carboxylic acid.

[0145] According to one embodiment of the present invention, R in Formula 4 41 It may be a C1-15 alkyl, C1-7 alkyl, C1-5 alkyl, or methyl, ethyl, or propyl.

[0146] According to one embodiment of the present invention, L in Formula 4 41 to L 43 The ions can be independently C1-15 alkylene, C1-7 alkylene, C1-3 alkylene, or methylene or ethylene.

[0147] According to one embodiment of the present invention, X in Formula 4 41 To X 43 The functional groups can be epoxy, acrylic, or vinyl polymerizable functional groups independently of each other.

[0148] According to one embodiment of the present invention, the hindered urea monomer to the polyfunctional monomer may satisfy a molar ratio of 0.5 to 1.5:1, a molar ratio of 0.7 to 1.2:1, or a molar ratio of 0.9 to 1.1:1. When the above ranges are satisfied, the physical properties targeted herein can be achieved.

[0149] According to one embodiment of the present invention, the hindered urea monomer and the polyfunctional monomer may not contain isocyanate groups. Isocyanates are substances derived from toxic compounds such as phosgene, which pose a significant risk to the environment and health, making them unsuitable for sustainable recycling processes. To address the conventional problems, the polyurea polymer according to one embodiment of the present invention exhibits high reactivity without using isocyanates during manufacturing. This enables recycling for the development of eco-friendly, sustainable materials that overcome the limitations of existing petroleum-based polymers, and allows for excellent physical properties even after recycling.

[0150] According to one embodiment of the present invention, the polyurea polymer may comprise the structure of the following chemical formula 5.

[0151] [Chemical Formula 5]

[0152]

[0153] In the above chemical formula 5,

[0154] A1 and A2 are independently heteroaromatic, cycloaliphatic, or heterocycloaliphatic rings, and

[0155] Y1 and Y2 are independently substituted or unsubstituted C1-30 alkylenes or C1-30 heteroalkylenes, and

[0156] L is a substituted or unsubstituted C1-30 alkylene or C1-30 heteroalkylene, and

[0157] R 41 is a C1-15 alkyl, and

[0158] L 41 to L 43 They are independently C1-15 alkylenes and

[0159] L5 is or And,

[0160] -* is a connector.

[0161] According to one embodiment of the present invention, in Formula 5, A1, A2, Y1, Y2 and L are identical to the definitions of Formula 2, and R 41 , L 41 to L 43 ...is omitted as it is identical to the definition of Chemical Formula 4.

[0162] According to one embodiment of the present invention, the polyurea polymer may have a gel content of 95% or more, 97% or more, or 99% or more. In particular, the polyurea polymer may exhibit superior mechanical properties by maintaining a high gel content even after recycling to form a robust network.

[0163] According to one embodiment of the present invention, the polyurea polymer may have a glass transition temperature (Tg) measured by DSC of -10 to 50°C, 0 to 30°C, or 1 to 20°C. Additionally, the glass transition temperature measured by DMA may be 0 to 80°C, 2 to 50°C, or 5 to 35°C. The Tg can be easily changed by adjusting the chain length of the monomer used according to the intended application.

[0164] According to one embodiment of the present invention, the polyurea polymer has a 5% thermal decomposition temperature (Td 5% ) may be 200°C or higher, 200 to 250°C, or 220 to 230°C.

[0165] According to one embodiment of the present invention, the polyurea polymer may have a tensile modulus (E) of 1 to 50 MPa, 2 to 20 MPa, or 3 to 10 MPa. Or it may be 10 to 500 MPa, 50 to 400 MPa, or 250 to 400 MPa.

[0166] According to one embodiment of the present invention, the polyurea polymer may have a tensile stress of 0.1 to 50 MPa, 1 to 40 MPa, or 2 to 30 MPa.

[0167] According to one embodiment of the present invention, the polyurea polymer may have an elongation of 10 to 300%, 10 to 300%, or 10 to 300%.

[0168] According to one embodiment of the present invention, the polyurea polymer may have an activation energy of 200 kJ / mol or less, 190 kJ / mol or less, or 50 to 185 kJ / mol at a temperature of less than 110°C.

[0169] According to one embodiment of the present invention, the polyurea polymer may have an activation energy of 200 kJ / mol or less, 100 kJ / mol or less, or 20 to 70 kJ / mol at a temperature of 110°C or higher and 120°C.

[0170] According to one embodiment of the present invention, the polyurea polymer satisfies the aforementioned range of physical properties, has excellent thermal and mechanical properties, allows for remolding, chemical recycling, and upcycling, and can maintain excellent mechanical properties even after recycling.

[0171] According to one embodiment of the present invention, the glass transition temperature (Tg_3 times) measured by DSC after cutting and heat pressing the polyurea polymer three times at 130°C for 30 minutes under a pressure of 10 MPa may be within the range of the initial glass transition temperature ± 10°C before the process. That is, Tg-10 ≤ Tg_3 times ≤ Tg+10 may be satisfied, and in this case, Tg is the glass transition temperature of the initial polyurea polymer before cutting and pressing.

[0172] According to one embodiment of the present invention, the polyurea polymer may have a three-dimensional cross-linked structure, which is a cured product resulting from the curing of a polyfunctional monomer.

[0173] According to one embodiment of the present invention, the polyurea polymer may comprise a dynamic covalent bond network. The polyurea polymer may form a dynamic covalent bond network as typically defined academically, and for example, the polyurea polymer may form a dynamic covalent bond network by including one or more bonds selected from a hindered urea bond, a thiol-Michael bond, and an ester bond. The type of bond may vary depending on the type of functional group of the polyfunctional monomer.

[0174] According to one embodiment of the present invention, the polyurea polymer may contain a hindered urea bond.

[0175] According to another embodiment of the present invention, the polyurea polymer may contain hindered urea bonds, thiol-Michael bonds, and ester bonds.

[0176] Chemical recycling may be possible when the above-described polyurea polymer includes the bonds described above. In particular, when two or more types of bonds are included, the activation energy is lowered below a certain temperature, allowing for various recycling methods such as easy re-molding, chemical recycling, and upcycling at lower temperatures. This solves the problem of recyclability of thermosetting polymers, and thanks to the reprocessability using dynamic bonds, it is possible to develop various industrial applications and environmentally friendly sustainable materials while maintaining the performance of the polymer.

[0177] The present invention can provide a chemical recycling method for a polyurea polymer comprising the step of dissolving the above-described polyurea polymer in a solvent and depolymerizing it into an oligomer.

[0178] According to one embodiment of the present invention, dynamic covalent bonds within the polyurea polymer may be dissociated during the depolymerization step. That is, the polyurea polymer can be chemically recycled by dissociating / depolymerizing one or more bonds selected from hindered urea bonds, thiol-Michael bonds, and ester bonds included in the polyurea polymer to form oligomers.

[0179] According to one embodiment of the present invention, the solvent may be an aprotic solvent or an alcohol solvent. The aprotic solvent may include an aprotic polar solvent such as dimethylformamide and / or dimethyl sulfoxide. Additionally, the alcohol solvent may include a primary alcohol such as methanol or ethanol, a secondary alcohol such as isopropyl alcohol, a dihydric alcohol such as ethylene glycol, or a polyol. In this case, the description of the polyol and specific examples of compounds are the same as those described below. The solvent may vary depending on the type of dynamic covalent bond to be dissociated.

[0180] According to one embodiment of the present invention, the solvent may further comprise a catalyst. The catalyst may be any one or more combinations selected from the group consisting of 1,8-diazabicyclo[5.4.0]undecene (DBU), 1,4-diazabicyclo[2.2.2]octane (DABCO), triethylamine, and 1,5-diazabicyclo[4.3.0]nonene (DBN). The content of the catalyst may be 0.1 to 20 mol%, 1 to 15 mol%, or 5 to 10 mol% with respect to the total molar amount of the polyurea polymer added.

[0181] According to one embodiment of the present invention, when the bonds included in the polyurea polymer are hindered urea bonds, the depolymerization may be performed by dissolving the polyurea polymer in a solvent, adding a hindered amine-based compound, and heating. The solvent may be a non-protic solvent, specifically dimethylformamide and / or dimethyl sulfoxide.

[0182] According to one embodiment of the present invention, the hindered amine-based compound may be represented by the following chemical formula 6.

[0183] [Chemical Formula 6]

[0184] L 6-( X 6)n6

[0185] In the above chemical formula 6,

[0186] L6 is an organic group of n6, and

[0187] n6 is an integer from 1 to 3, and

[0188] X6 is And,

[0189] The above A6 is a heteroaromatic, cycloaliphatic, or heterocycloaliphatic ring.

[0190] According to one embodiment of the present invention, when n6 in the formula 6 is 2 or more, each L6 may be different from each other, and L6 may be a substituted or unsubstituted C1-30 alkylene or a C1-30 heteroalkylene or an unsubstituted C1-7 alkylene.

[0191] According to one embodiment of the present invention, in the above formula 6, A6 may be a heterocyclic ring, a nitrogen-containing C3-30 heterocyclic ring, or a nitrogen-containing C4-15 heterocyclic ring.

[0192] According to one embodiment of the present invention, the hindered amine-based compound may be represented by the following chemical formula 7.

[0193] [Chemical Formula 7]

[0194]

[0195] In the above chemical formula 7, L7 may be a substituted or unsubstituted C1-30 alkylene.

[0196] According to one embodiment of the present invention, L7 may be a substituted or unsubstituted C1-30 alkylene, an unsubstituted C1-15 alkylene, or an unsubstituted C1-7 alkylene.

[0197] According to one embodiment of the present invention, when the bonds included in the polyurea polymer are thiol-Michael bonds, the depolymerization can be performed by dissolving the polyurea polymer in a solvent, adding the catalyst, and heating. The solvent may be an aprotic solvent or an alcohol solvent, and specifically, primary alcohols such as dimethylformamide, dimethyl sulfoxide, methanol, and ethanol, secondary alcohols such as isopropyl alcohol, and dihydric alcohols such as ethylene glycol may be used.

[0198] According to one embodiment of the present invention, when the bonds included in the polyurea polymer are ester bonds, the depolymerization can be performed by dissolving the polyurea polymer in a solvent, adding the catalyst, and heating. The solvent may be a polyol.

[0199] According to one embodiment of the present invention, the depolymerization may be performed at 120°C or lower, 100°C or lower, 30 to 100°C, or 50 to 90°C. In addition, the depolymerization may be performed for 1 hour or more, 5 hours or more, or 10 hours or more, but is not limited thereto.

[0200] According to one embodiment of the present invention, the dissociated oligomer can be easily controlled depending on the amount of catalyst added and the dissociation (depolymerization) time, but may be 100 to 50,000 g / mol, 100 to 30,000 g / mol, 100 to 10,000 g / mol, or 100 to 5,000 g / mol. In addition, the depolymerized oligomer may include all cases of oligomer structures that can be formed when dynamic covalent bonds contained in a polyurea polymer are dissociated, according to the common knowledge of a person skilled in the field of chemistry.

[0201] According to one embodiment of the present invention, a step of curing a polymerizable composition comprising the oligomer and the polymerizable monomer may be further performed.

[0202] The above polymerizable monomer may be used without significant limitation as long as it is a monomer containing one or more functional groups selected from the group consisting of the aforementioned epoxy, acrylic, vinyl, alkyl halide, aldehyde, ketone, carbonyl, carboxylic acid, ester, maleimide, and alkene. As another example, the above polymerizable monomer may be represented by Chemical Formula 4.

[0203] The present invention may provide a method for upcycling a polyurea polymer comprising the steps of: depolymerizing the aforementioned polyurea polymer in the presence of a solvent and a catalyst to obtain an oligomer; and reacting the oligomer with a polymer. In this case, the polyurea polymer may contain ester bonds within its main chain, and upcycling may be possible by reacting with a polyol solvent described later.

[0204] The above depolymerization can be carried out by dissolving the polyurea polymer in a solvent, adding the catalyst, and heating. The description of the catalyst and examples of specific compounds are the same as those described above.

[0205] According to one embodiment of the present invention, the solvent may be a polyol. The polyol refers to a compound containing two or more hydroxyl groups. The polyol may be an aliphatic, alicyclic, and aromatic polyol compound; or a polyester polyol and a polyester polyol compound; or a polyol containing two hydroxyl groups is called a diol, a polyol containing three hydroxyl groups is called a triol, and a polyol containing four hydroxyl groups is called a tetraol.

[0206] Specifically, the polyol may be a diol or a triol, and a mixture of both may be used. More specifically, it may be a diol, specifically ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,4-butenediol, 1,4-butenediol, 1,5-pentanediol, neopentyl glycol, bis(hydroxymethyl)cyclohexane, 2-methyl-1,3-propanediol, methylpentanediol; also, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol, dibutylene glycol, polybutylene glycol, polytetrahydrofuran, polycarbonate diol, and polycaprolactone diol, etc., but are not limited thereto.

[0207] According to one embodiment of the present invention, the depolymerization may be performed at 120°C or lower, 100°C or lower, 30°C or lower, or 100°C, or 50°C to 90°C. In addition, the depolymerization may be performed for 1 hour or more, 5 hours or more, or 10 hours or more, but is not limited thereto.

[0208] According to one embodiment of the present invention, the depolymerized oligomer may contain a hydroxyl group at the terminal end as shown in FIG. 9. The oligomer may be cured by reacting with a polymer. The curing may be performed under normal conditions and may be performed for a sufficient amount of time at a temperature of 100°C or higher.

[0209] According to one embodiment of the present invention, the polymer may contain a functional group selected from the group consisting of epoxides, acyl halides, carboxylic acids, isocyanates, carbonates, anhydrides, and aldehydes. As an example, the polymer may be used without limitation if it is a polymer containing one or more structures selected from the group consisting of -O(C=O)-, -(C=O)O-, -O(C=O)O-, and -(C=O)O(C=O)- in the main chain or side chain. As an example, a polyacrylic acid containing a carboxylic acid in the side chain may be used.

[0210] The present invention will be explained in more detail based on the following examples. However, the following examples are merely illustrative of the present invention and do not limit the present invention.

[0211] [Methods for Measuring Physical Properties]

[0212] 1) Gel content (gel%)[%]

[0213] After adding the prepared film to the DMF (Dimethylformamide) solvent and leaving it for 24 hours, the undissolved portion was extracted and dried, and the yield was calculated as a percentage.

[0214] 2) Molecular weight

[0215] Gel permeation chromatography (GPC) was used to analyze the number-average molecular weight, weight-average molecular weight, and polydispersity index using an LC4000 series chromatograph (JASCO) equipped with an RI-4030 refractive index detector. DMF (containing 1 M LiBr) was used as the eluent at a flow rate of 1.0 mL / min, and the molecular weight was calculated using ChromNAV2 software along with a polystyrene (PS) standard.

[0216] 3) Thermal decomposition temperature (Td 5% The thermal decomposition temperature at which an initial 5% weight loss occurred was measured using thermogravimetric analysis (TA Instruments, TGA Q500) of the prepared polyurea polymer. The measurement conditions were a 60 ml / min nitrogen injection atmosphere, a temperature range from room temperature to 700 ℃, and a heating rate of 10 ℃ / min.

[0217] 4) Glass transition temperature (Tg): The glass transition temperature of the prepared polyurea polymer was measured using differential scanning analysis (DSC, TA instruments, DSC Q2000). The measurement was performed under a 50 ml / min nitrogen injection atmosphere using a Tzero Al sample pan and lid at a heating rate of 10 ℃ / min in a temperature range of -40 to 80 ℃.

[0218] 5) Dynamic Machine Analysis (DMA)

[0219] Analysis was performed using a TA Instruments DMA Q800 equipped with a film tension clamp, and through Temperature Sweep data, the film's tan δ value and the temperature at which tan δ reaches a maximum (T tanδ Tg (analyzed by DMA), storage modulus, and loss modulus were determined. The measurement method used was a temperature range of -50℃ to 150℃, frequency of 1 Hz, strain of 0.5%, and heating rate of 3℃ per minute. Additionally, an Arrhenius plot was obtained from the stress-relaxation data, and the activation energy was calculated from it using the equation described below.

[0220] Activation energy (E a The [kJ / mol] value was calculated using the value obtained through DMA and the Arrhenius equation described below.

[0221]

[0222] Here, T is the absolute temperature, and τ is the e of the A value at stress-relaxation. -1 The time required to decrease by a factor of two (relaxation time), A is an exponential constant, and R is a gas constant.

[0223] 6) Flow characteristics

[0224] Flow characteristics were analyzed using a vibrating rheometer (Anton Paar, MCR 102) equipped with a 25 mm parallel plate. Changes in the complex viscosity of the film during repetitive heating and cooling cycles were measured at a constant frequency of 1 Hz, a strain of 1%, and an axial force of 1 N, and the samples were heated and cooled at a rate of 10 ℃ / min.

[0225] 7) Mechanical properties

[0226] Elastic modulus (modulus, E, MPa) and tensile strength (σ) from the Stress-Strain Curve obtained using the Universal Tensile Machine (Qmesys QM100S) max , MPa) and elongation at break (ε max , %) was measured. The specimen was prepared with dimensions of 4 cm x 0.5 cm x 0.2 mm (thickness) and the tensile speed was measured at 60 mm / min.

[0227]

[0228] [Preparation Example 1] Synthesis of thiazolidin-2-one (TZ)

[0229] 2-aminoethanethiol hydrochloride (30.00 g, 264.08 mmol) and urea (23.79 g, 396.13 mmol) were added to a 250 mL single-neck round-bottom (RB) flask. A condenser was installed, and the RB flask was heated to 180 °C and the reaction was carried out for 3 hours. After cooling the reaction mixture to room temperature (RT), it was diluted with ethyl acetate. After filtration, the filtrate was dried and further purified by column chromatography (using ethyl acetate as the solvent) to obtain the target product (TZ) in the form of a white solid (23.15 g, yield 85%).

[0230] 1 H and 13 13C NMR spectra were analyzed using a Bruker 300 and 75 MHz spectrometer, and the sample was CDCl3( 1 H: 7.26 ppm; 13 C: 77.16 ppm), DMSO-d6( 1 H: 2.50 ppm), or DMF-d7( 1 It was dissolved in H: 8.03 ppm). The coupling constant (J) is expressed in Hertz (Hz).

[0231] 1 H NMR (300 MHz, CDCl3) δ 6.77 (s, 1H), 3.63 (t,J= 7.1 Hz, 2H), 3.40 (t,J= 6.9 Hz, 2H).

[0232] 13 C NMR (75 MHz, CDCl3) δ 176.75, 43.47, 30.14.

[0233]

[0234] [Preparation Example 2] Synthesis of 4,4'-(propane-1,3-diyl)bis(N-(2-mercaptoethyl)piperidine-1-carboxamide) (TZ-DPP)

[0235]

[0236] TZ (1.00 g, 9.70 mmol) prepared in Preparation Example 1 was added to a 20 mL vial and heated and dissolved at 80 °C for 10 minutes. Subsequently, 4,4'-Trimethylenedipiperidine (1.02 g, 4.85 mmol) dissolved in DMF (2.02 g, 2.14 mL) was added to the vial, and the mixture was reacted at 80 °C for 4 hours while stirring. After cooling the reaction mixture to room temperature (RT), the compound was used without further purification. For characterization, the solution was precipitated in diethyl ether, and the resulting solid compound was washed with diethyl ether and dried under vacuum to obtain TZ-DPP.

[0237] 1 H NMR (300 MHz, CDCl3) δ 4.98 (t,J= 5.7 Hz, 2H), 3.91 (dt,J= 12.9, 2.6 Hz, 4H), 3.38 (q,J= 6.1 Hz, 4H), 2.83-2.69 (m, 4H), 2.67 (t,J= 6.3 Hz, 4H), 1.67 (d,J= 10.4 Hz, 4H), 1.35-1.03 (m, 12H).

[0238] 13 C NMR (75 MHz, CDCl3) δ 157.46, 44.40, 43.81, 36.68, 35.97, 32.12, 25.59, 23.63.

[0239] High-resolution mass spectra (HRMS), a Jeol AccuTOF 4G+ DART (ESI): calcd for C 19 H 36 N4O2S2[M+H + ]: 416.2280; found: 417.2353.

[0240]

[0241] [Example 1] Synthesis of Polyurea Polymer

[0242] A polymerizable composition containing TZ-DPP diluted with DMF according to Preparation Example 2 and trimethylolpropane triacrylate (TA) in a 1:1 molar ratio was thoroughly mixed in a beaker and then poured into a Teflon mold. The mixture was cured at 60°C for 18 hours, cured at 80°C for 24 hours, and dried in a vacuum oven at 80°C for 24 hours to finally obtain a polyurea polymer (TZ-DPP-TA).

[0243] [Example 2]

[0244] A polyurea polymer (TZ-DPP-TE) was obtained by performing the same procedure as in Example 1, except that trimethylolpropane diglycidyl ether (TE) was used instead of trimethylolpropane triacrylate in Example 1.

[0245]

[0246] Figure 2 shows the FT-IR spectra for the polyurea polymers of Examples 1 and 2. The spectrum of TZ-DPP-TA showed a carbonyl peak attributed to the ester group, and both the TZ-DPP-TA and TZ-DPP-TE spectra showed carbonyl and NH peaks attributed to the urea bond.

[0247] Gel content of the polyurea polymer in Examples 1 and 2 above, 5% thermal decomposition temperature (Td 5% ), glass transition temperature (Tg), elastic modulus (E, tensile modulus), tensile stress, elongation at break, and activation energy (E) analyzed by DSC and DMA a ) was measured and shown in Table 1 below. In addition, the SS curve (stress-strain curve) of the polyurea polymers of Examples 1 and 2 above is shown in FIG. 3, and the graph of the storage modulus and tan δ analyzed by DMA is shown in FIG. 4.

[0248] Referring to Figure 4, the storage modulus (E') initially gradually decreased and then stabilized for a while, and subsequently, as the temperature increased, the storage modulus (E') decreased again. This trend was interpreted as reflecting the dissociative characteristics of the dynamic covalent bond network.

[0249] Example 1 (TZ-DPP-TA) Example 2 (TZ-DPP-TE) Gel%[%]9998Td 5% [℃]228229Tg[℃] (DSC)3.517.5Tg[℃] (DMA)9.332.83E[MPa]3.7 ± 0.1316 ± 33σ max [MPa]2.6 ± 0.223.1 ± 2.1ε max [%]140 ± 6102 ± 13E a [kJ / mol] 183±21 (less than 110℃) 59±3 (110℃ or higher) 172±14 (less than 110℃)

[0250] Additionally, the stretching exponent (β) was calculated for each temperature using the Williams-Watts (KWW) function represented by the following formula based on the DMA analysis results of the polyurea polymers of Examples 1 and 2, and is shown in Table 2 below.

[0251] [ceremony]

[0252]

[0253] In the above equation, t is time, τ * ε is a specific relaxation time and β is the stretching index.

[0254] When β < 1, it exhibits a distribution of relaxation times that is commonly seen in complex or disordered systems and expands during relaxation, and when β = 1, the KWW function contracts to a simple exponential decrease, exhibiting a single relaxation-time process similar to the Maxwell model.

[0255] Temperature [°C] Example 1 (TZ-DPP-TA) Example 2 (TZ-DPP-TE) 900.83-1000.83-1101.00-1201.000.521301.000.621401.000.761501.001.00

[0256] In Tables 1 and 2 above, it was confirmed that the polymer of Example 1 reached β1 at 110°C, and the polymer of Example 2 reached β1 at 150°C. Through this, it was confirmed that the polymer according to one example forms an ideal covalent adaptive network at each temperature in which β1 is reached.

[0257] Furthermore, TZ-DPP-TA exhibited an activation energy of 183 ± 21 kJ / mol at temperatures below 110°C; conversely, TZ-DPP-TE, whose dynamic characteristics are primarily attributed to HUB (Hindered Urea Bond) binding, reacted over a higher temperature range, showing an activation energy of 172 ± 14 kJ / mol at 150°C. Additionally, for TZ-DPP-TA, the activation energy decreased sharply to 59 ± 3 kJ / mol when the temperature exceeded 110°C, which was predicted to be mainly due to the dynamic characteristics of the thiol-Michael addition reaction. Through this, it was confirmed that TZ-DPP-TA can react more dynamically at lower temperatures than TZ-DPP-TE.

[0258]

[0259] [Evaluation Example 1] Reshaping Evaluation

[0260] The polyurea polymer films of Examples 1 and 2 prepared were cut into small pieces measuring 0.5 cm x 0.5 cm or less, and reshaped multiple times (1st, 2nd, 3rd, 4th, and 5th times) by pressing at 10 MPa and 130 °C for 30 minutes. The gel content of the reshaped film and the 5% thermal decomposition temperature (Td) 5%The glass transition temperature (Tg), elastic modulus (E, Tensile modulus), tensile stress, and elongation were measured using DSC and DMA analysis and are shown in Table 3 below.

[0261] In this case, if the sample was a re-molded version of Example 1 once, it was described as 'Example_1'. Additionally, because TZ-DPP-TA has a lower activation energy than TZ-DPP-TE at temperatures above 110°C, it exhibited superior processability through the effective recovery of shape and material properties.

[0262] Gel%[%]T d5% [℃]Tg[℃] (DSC)Tg[℃] (DMA)E[MPa]σ max [MPa]ε max [%] Example 1 > 992283.59.33.7±0.12.6±0.2140±6 Example 1_1st time > 992262.35.23.8±0.23.1±0.1170±16 Example 1_2nd time > 992304.110.54.1±0.52.4±0.2165±17 Example 1_3rd time > 992265.810.69.0±2.13.4±0.2194±2 Example 1_4th time > 992285.410.815.9±1.25.2±0.1208±2 1 Example 1_5 times > 992336.517.932.3±5.85.0±0.4211±15 Example 2 9822917.532.83316±3323.1±2.1102±13 Example 2_1 time 9822712.735.71351±2322.9±0.892±5 Example 2_2 times 9823010.741.75304±2920.7±1.092±1 Example 2_3 times 9822811.148.50377±216.2±1.678±7

[0263] As shown in Table 3 above, both Example 1 (TZ-DPP-TA) and Example 2 (TZ-DPP-TE) exhibited gel content and thermal stability even after repeated remolding. In particular, Example 1 showed a tendency for the elastic modulus, tensile strength, elongation, and glass transition temperature to increase as the number of remolding cycles increased, indicating that the mechanical and thermal properties of the polymer improved after repeated remolding. Furthermore, the activation energy at 110°C or higher was 59±3 kJ / mol for Example 1 and 69±7 kJ / mol for the Example 1_5th remolding sample; since no significant difference in activation energy was observed even after remolding, it was found that the changes observed in the thermal and mechanical properties between the samples were mainly attributed to the rearrangement of the TZ-DPP-TA polymer.

[0264] In addition, in Example 2, as the number of reshaping cycles increases, T in DMA tanδ The value increased, yet stable mechanical properties were maintained. It was confirmed that this stability is primarily attributed to the robust chemical structure of TZ-DPP-TE.

[0265]

[0266] [Evaluation Example 2] Evaluation of Chemical Solubility

[0267] The polyurea polymer films of Examples 1 and 2 prepared were cut into small pieces of 0.5 cm x 0.5 cm or smaller, and the chemical solubility of the polymer was evaluated by adding (1) piperidine in the same molar amount as the polymer to 10 ml of the following solvent, or (2) adding 5 mol% of 1,8-diazabicyclo[5,4,0]undek-7-ene (DBU) relative to the total molar amount of the polymer and heating at the corresponding temperature for 1 hour. The chemical solubility was evaluated as ○ if it dissolved transparently, and Х otherwise, and is shown in Table 4 below.

[0268] Piperidine Equivalent Input THF 1,4-Dioxane EtOH Me CND MF DMSO Temperature [℃] 60 100 80 80 80 80 Example 1 XXXXXX Example 2 XXXXXX (100℃) XX (100℃) DBU 5 mol% Input THF 1,4-Dioxane EtOH Me CND MF DMSO Temperature [℃] 60 100 80 80 80 80 80 Example 1 XXXXXXXX Example 2 XXXXXX (100℃) XX (100℃)

[0269] - THF: Tetrahydrofuran

[0270] - 1,4-Dioxane : 1,4-dioxane

[0271] - EtOH: Ethanol

[0272] - MeCN: Acetonitrile

[0273] - DMF: Dimethylformamide

[0274] - DMSO: Dimethyl sulfoxide

[0275] As shown in Table 4 above, it was confirmed that the polymer network structures of Examples 1 and 2 chemically dissociated (depolymerized) by forming dynamic HUBs (hind-the-urea bonds) with piperidine under DMF or DMSO solvents. However, no chemical dissociation occurred in THF, EtOH, or MeCN, which suggests that the dynamic covalent bond networks of the polymers in Examples 1 and 2 can be selectively dissociated.

[0276] In addition, unlike Example 2, the polymer network of Example 1 completely dissolved when heated in the presence of DBU, which confirmed that the dynamic covalent bond network was dissociated through the retro-Michael addition process as the polymer network of Example 1 contained thiol-Michael bonds.

[0277] Additionally, unlike Example 2, the polymer network of Example 1 had a film that dissolved in EtOH, which confirmed that the dynamic covalent network was dissociated through transesterification as the polymer network of Example 1 contained ester bonds.

[0278]

[0279] Figure 6 illustrates a schematic diagram briefly showing the chemical recycling described below. Figure 6 (a) shows the chemical recycling of the polymer using hindered urea bonds and thiol-Michael bonds of the polymer of Example 1, Figure 6 (b) shows the chemical recycling of the polymer using hindered urea bonds of the polymer of Example 2, and Figure 6 (c) shows the chemical recycling and upcycling using ester bonds of the polymer of Example 1.

[0280]

[0281] [Evaluation Example 3] Chemical Recycling

[0282] (1) Chemical recycling of polymers using hindered urea bonds

[0283] The polyurea polymer film of Example 1 prepared was cut into small pieces of 0.5 cm x 0.5 cm or smaller, dissolved in 10 ml of DMF, and then 4,4'-trimethylenedipiperidine was added in an equimolar amount to the polymer and heated at 80°C for 12 hours to completely dissolve it. During this process, hindered urea bonds were depolymerized to prepare an oligomer containing piperidine terminal groups, which was analyzed by NMR, and the obtained NMR spectrum is shown in Figure 5.

[0284] Next, the oligomer obtained from the TZ of Preparation Example 1 was added to the dissolved mixture in an equimolar amount, and a ring-opening reaction with the TZ was performed at 80°C for 2 hours. Then, trimethylolpropane triacrylate was added to the mixture in an equal molar amount to the TZ. After thoroughly mixing the prepared polymerizable composition, it was poured back into a Teflon mold and dried to form a film in the same manner as in Example 1. Through this process, a recycled polyurea polymer (TZ-DPP-TA, Recycled_HU) utilizing hindered urea bonds was obtained.

[0285]

[0286] In addition, chemical recycling of Example 2 was performed by carrying out the same process but using the polyurea polymer film of Example 2 instead of Example 1, and using trimethylolpropane diglycidyl ether instead of trimethylolpropane triacrylate, thereby obtaining a recycled polyurea polymer (TZ-DPP-TE, Recycled_HU) using hindered urea bonds.

[0287] Figure 7 shows the FT-IR spectra of the polymer of Example 2 (TZ-DPP-TE) and the polyurea polymer recycled using hindered urea bonds (Recycled_HU). The peak of the chemically recycled polymer was identical to the chemical structure of TZ-DPP-TE, confirming that no side reactions occurred during the chemical recycling process.

[0288] In addition, the mechanical and thermal properties of TZ-DPP-TA and Recycled_HU were measured and are shown in Table 5 below.

[0289] TZ-DPP-TERecycled_HUGel%[%]9897Td 5% [℃]229222Tg[℃] (DSC)17.511.2Tg[℃] (DMA)32.8328.2E[MPa]316 ± 33188 ± 9σ max [MPa]23.1 ± 2.112.9 ± 0.6εmax [%]102 ± 1393 ± 8

[0290]

[0291] (2) Chemical recycling of polymers using thiol-Michael bonds

[0292] The polyurea polymer film of Example 1 prepared was cut into small pieces of 0.5 cm x 0.5 cm or smaller, dissolved in 10 ml of DMF, 5 mol% of DBU was added, and heated at 80°C for 24 hours to completely dissolve it. During this process, thiol-Michael bonds were depolymerized by retro-Michael addition to prepare an oligomer.

[0293] The prepared mixture was precipitated with diethyl ether, and the precipitated solid (yield: 68%), which is the depolymerized oligomer, was further dissolved in DMF. The resulting composition was poured into a Teflon mold and dried to form a film in the same manner as in Example 1. Analysis of the low molecular weight oligomer remaining in the diethyl ether after precipitation revealed a Tg of -20°C, indicating that some low molecular weight oligomers had been separated. Through this process, a recycled polyurea polymer (TZ-DPP-TA, Recycled_TM) utilizing thiol-Michael bonds was obtained.

[0294] Figure 8 shows the FT-IR spectra of the polymer of Example 1 (TZ-DPP-TA), the polyurea polymer recycled using hindered urea bonds (Recycled_HU), and the polyurea polymer recycled using thiol-Michael bonds (Recycled_TM). The chemically recycled polymer peaks were all identical to the chemical structure of TZ-DPP-TA, confirming that no side reactions occurred during the chemical recycling process.

[0295] In addition, the mechanical and thermal properties of TZ-DPP-TA, Recycled_HU, and Recycled_TM were measured and are shown in Table 6 below.

[0296] TZ-DPP-TARecycled_HURecycled_TMGel%[%]999898Td 5% [℃]228228231Tg[℃] (DSC)3.59.336.2Tg[℃] (DMA)9.315.630.8E[MPa]3.7 ± 0.13.2 ± 0.6464 ± 34σ max [MPa]2.6 ± 0.23.2 ± 0.327.8 ± 0.5ε max [%]140 ± 6326 ± 196.7 ± 0.2

[0297] As shown in Table 6 above, it was found that Recycled_HU had thermal and mechanical properties similar to TZ-DPP-TA. However, Recycled_TM exhibited significantly improved mechanical strength as low molecular weight oligomers were separated, and showed a considerably higher Tg compared to TZ-DPP-TA.

[0298]

[0299] (3) Chemical recycling of polymers using ester bonds

[0300] The polyurea polymer film of Example 1 prepared was cut into small pieces measuring 0.5 cm x 0.5 cm or less, dissolved in 10 ml of ethylene glycol, 5 mol% of DBU was added, and heated at 80°C for 24 hours to completely dissolve it. During this process, the ester bonds underwent a transesterification reaction to produce a depolymerized dihydroxyl oligomer, and the prepared oligomer was washed with ethyl acetate. Subsequently, the obtained viscous liquid was vacuum dried at 80°C for 24 hours to remove the remaining ethylene glycol, thereby producing a dihydroxyl oligomer (TZ-DPP-EG).

[0301] Figure 9 shows the NMR spectra obtained by NMR analysis of the TZ-DPP of Preparation Example 2 and the dihydroxyl oligomer (TZ-DPP-EG). The appearance of characteristic peaks of the ethylene group at δ 4.25 and 3.83 ppm (in CDCl3) in the NMR spectrum of TZ-DPP-EG suggests that successful glycolysis was achieved.

[0302]

[0303] [Evaluation Example 4] Upcycling

[0304] A composition prepared by dissolving 0.4g of TZ-DPP-EG and 0.84g of polyacrylic acid (PAA, 450 kDa) in 4ml of DMSO in Evaluation Example 3 was poured into a Teflon mold, cured at 120°C for 24 hours, and dried in a vacuum oven at 80°C for 48 hours to finally obtain an upcycled polyurea polymer film (TZ-DPP-EG-PAA).

[0305] In addition, the mechanical and thermal properties of TZ-DPP-TA and TZ-DPP-EG-PAA were measured and are shown in Table 7 below, and the FT-IR spectrum of TZ-DPP-EG-PAA is shown in Figure 10.

[0306] TZ-DPP-TATZ-DPP-EG-PAATg[℃] (DSC)3.578.6E[MPa]3.7 ± 0.1399 ± 10σ max [MPa]2.6 ± 0.220 ± 1ε max [%]140 ± 611 ± 2

[0307] As shown in Tables 5 to 7 above, the polyurea polymer film according to one embodiment demonstrates various possibilities for recycling and upcycling. It can be seen that this is a very excellent recycling method, as there is no significant degradation of physical properties even after chemical recycling, and in some cases, the physical properties are even improved. In particular, the chemical recycling method using the ester bonds of the polymer in Example 1 has the advantage of enabling more eco-friendly recycling by reducing energy consumption through the use of a non-toxic polyol solvent instead of the high boiling point polar aprotic solvent mentioned above.

[0308] Accordingly, the polyurea polymer according to one embodiment of the present invention has the potential to be an environmentally friendly future material by demonstrating excellent performance along with the possibility of recycling and upcycling. Accordingly, the polyurea polymer can be widely used in the fields of sustainable chemistry and materials science.

[0309] The invention described above is merely illustrative, and those skilled in the art will readily understand that various modifications and equivalent alternative embodiments are possible therefrom. Therefore, it will be well understood that the invention is not limited only to the forms mentioned in the detailed description above. Accordingly, the true scope of technical protection of the invention should be determined by the technical spirit of the appended claims.

[0310] Accordingly, the scope of the present invention is not limited to the described embodiments, and all things equivalent to or having equivalent variations to the claims set forth below, as well as the claims set forth below, shall be considered to fall within the scope of the concept of the present invention.

Claims

1. A polyurea polymer prepared from a polymerizable composition comprising a hindered urea monomer and a polyfunctional monomer represented by the following chemical formula 1. [Chemical Formula 1] L-(X)n In the above chemical formula 1, L is an n-valent organic group, and n is an integer from 2 to 5, and X is And, The above A is a heteroaromatic, cycloaliphatic, or heterocycloaliphatic ring, and The above Y is a substituted or unsubstituted C1-30 alkylene or C1-30 heteroalkylene.

2. In Paragraph 1, The above hindered urea monomer is a polyurea polymer represented by the following chemical formula 2. [Chemical Formula 2] In the above chemical formula 2, A1 and A2 are independently heteroaromatic, cycloaliphatic, or heterocycloaliphatic rings, and Y1 and Y2 are independently substituted or unsubstituted C1-30 alkylenes or C1-30 heteroalkylenes, and L is a substituted or unsubstituted C1-30 alkylene or C1-30 heteroalkylene.

3. In Paragraph 1, The above hindered urea monomer is a polyurea polymer represented by the following chemical formula 3. [Chemical Formula 3] In the above chemical formula 3, Y1 and Y2 are independently substituted or unsubstituted C1-7 alkylenes, and L is a substituted or unsubstituted C1-15 alkylene.

4. In Paragraph 1, The above-mentioned polyfunctional monomer is a polyurea polymer containing three or more functional groups capable of reacting with thiol groups.

5. In Paragraph 1, The above-mentioned polyfunctional monomer is a polyurea polymer containing one or more selected from the group consisting of epoxy, acrylic, vinyl, alkyl halide, aldehyde, ketone, carbonyl, carboxylic acid, ester, maleimide, and alkene.

6. In Paragraph 1, The above-mentioned polyfunctional monomer is a polyurea polymer represented by the following chemical formula 4. [Chemical Formula 4] In the above chemical formula 4, R 41 is a C1-15 alkyl, and L 41 to L 43 They are independently C1-15 alkylenes, and X 41 To X 43 They are independently epoxy, acrylic, vinyl, alkyl halide, aldehyde, or carboxylic acid.

7. In Paragraph 1, The above hindered urea monomer to polyfunctional monomer is a polyurea polymer satisfying a molar ratio of 0.5 to 1.5:

1.

8. In Paragraph 1, The above hindered urea monomer and polyfunctional monomer are polyurea polymers that do not contain isocyanate groups.

9. In Paragraph 1, The above polyurea polymer is a polyurea polymer comprising the structure of the following chemical formula 5. [Chemical Formula 5] In the above chemical formula 5, A1 and A2 are independently heteroaromatic, cycloaliphatic, or heterocycloaliphatic rings, and Y1 and Y2 are independently substituted or unsubstituted C1-30 alkylenes or C1-30 heteroalkylenes, and L is a substituted or unsubstituted C1-30 alkylene or C1-30 heteroalkylene, and R 41 is a C1-15 alkyl, and L 41 to L 43 They are independently C1-15 alkylenes and L5 is or And, -* is a connector.

10. In Paragraph 1, The above polyurea polymer is a polyurea polymer having a gel content of 95% or more.

11. In Paragraph 1, The above polyurea polymer is a polyurea polymer having a glass transition temperature of -10 to 50°C as measured by DSC.

12. In Paragraph 1, A polyurea polymer in which the glass transition temperature measured by DSC after performing cutting and heat pressing three times at 130°C for 30 minutes under a pressure of 10 MPa falls within the range of the initial glass transition temperature ± 10°C prior to the process.

13. In Paragraph 1, The above polyurea polymer is a polyurea polymer having an activation energy of 200 kJ / mol or less at 120°C.

14. In Paragraph 1, The above polyurea polymer is a polyurea polymer comprising a dynamic covalent bond network.

15. In Paragraph 1, The above polyurea polymer is a polyurea polymer comprising one or more bonds selected from hindered urea bonds, thiol-Michael bonds, and ester bonds.

16. A method for chemically recycling a polyurea polymer comprising the step of dissolving a polyurea polymer selected from any one of claims 1 to 15 in a solvent and depolymerizing it into an oligomer.

17. In Paragraph 16, The above solvent is a chemical recycling method for polyurea polymers, which is an aprotic solvent or an alcohol solvent.

18. In Paragraph 16, The above solvent is a chemical recycling method for polyurea polymers that further includes a catalyst.

19. In Paragraph 18, A method for chemically recycling a polyurea polymer in which the catalyst is any one or a combination of two or more selected from the group consisting of 1,8-diazabicyclo[5.4.0]undecene (DBU), 1,4-diazabicyclo[2.2.2]octane (DABCO), triethylamine, and 1,5-diazabicyclo[4.3.0]nonene (DBN).

20. In Paragraph 16, A chemical recycling method for a polyurea polymer that further performs the step of curing the above-mentioned oligomer and polymerizable monomer.

21. In Paragraph 16, A chemical recycling method for a polyurea polymer in which the above depolymerization is performed at 120°C or lower.

22. A method for upcycling a polyurea polymer comprising the steps of: depolymerizing a polyurea polymer selected from any one of claims 1 to 15 in the presence of a solvent and a catalyst to obtain an oligomer; and reacting the oligomer with a polymer.

23. In Paragraph 22, The above solvent is a method for upcycling a polyurea polymer, which is a polyol.

24. In Paragraph 22, The above polymer is a method for upcycling a polyurea polymer containing a functional group selected from the group consisting of epoxides, acyl halides, carboxylic acids, isocyanates, carbonates, anhydrides, and aldehydes.

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