Polycarbonate oligomer, manufacturing method thereof, curable composition, epoxy crosslinked product, and method for degrading epoxy crosslinked product by aminolysis

Abstract

Polycarbonate oligomers, a method for manufacturing polycarbonate oligomers, a curable composition, an epoxy crosslinked product, and a method for degrading an epoxy crosslinked product by gaamine degradation are provided. The polycarbonate oligomer comprises a structure represented by Structural Formula I, Structural Formula I is defined herein.

Description

Technology Field

[0001] The present invention relates to an oligomer and a method for manufacturing the same. More specifically, the present invention relates to a polycarbonate oligomer, a method for manufacturing the same, a curable composition, an epoxy crosslinked product prepared thereby, and a method for degrading the epoxy crosslinked product by aminolysis. Background Technology

[0002] Currently in the industry, polycarbonate (PC) is produced by the transesterification of bisphenol A and diphenyl carbonate at high temperatures. Polycarbonate is a polymer material with excellent optical and mechanical properties and is widely used in drinking buckets, optical discs, data access, automotive parts, and other consumer goods.

[0003] Nowadays, polycarbonate recycling is still primarily carried out physically through mechanical processing or physical mixing, and defects in the physical properties of the recycled material are compensated for by adding new materials. Although the process is relatively simple, its application remains significantly limited because the physical properties of polycarbonate are easily destroyed during the recycling process. Furthermore, when mixed with epoxy resin for re-curing, it is often still necessary to dissolve the polycarbonate and epoxy resin in a solvent for the subsequent curing process. Therefore, the re-curing and reuse of existing polycarbonate after recycling still requires the involvement of solutions, which is inconvenient to work with and detrimental to the environment.

[0004] In response to future recycling issues, many academic papers have begun discussing chemical recycling methods that obtain bisphenol A monomer (BPA) through decomposition and return it to the synthesis of polycarbonates. However, obtaining high-purity bisphenol A monomer using this method requires large amounts of solvent and cumbersome separation and purification steps, which increases the difficulty of industrialization.

[0005] Therefore, the goal of the industry is to determine how to use waste polycarbonate as a curing agent for epoxy resin and to cure it with epoxy resin so that the crosslinked product has properties that allow it to be recycled and degraded in order to achieve sustainable utilization of waste polycarbonate.

[0006] According to one aspect of the present invention, a polycarbonate oligomer is provided. The polycarbonate oligomer comprises a structure represented by structural formula (I):

[0007] structural formula (I),

[0008] Here, R1 is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an allyl group, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom, and R2 is an alkyl group having 1 to 10 carbon atoms, an ether group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, a structure represented by structural formula (1), structural formula (2), structural formula (3), structural formula (4), structural formula (5), structural formula (6), or structural formula (7):

[0009]

[0010] Structure formula (1), structure formula (2), structure formula (3), structure formula (4), structure formula (5),

[0011]

[0012] Structural formula (6), structural formula (7),

[0013] Here, X is a structure represented by a single bond, structure formula (8), structure formula (9), structure formula (10), structure formula (11), structure formula (12), structure formula (13), structure formula (14), structure formula (15), structure formula (16), structure formula (17) or structure formula (18):

[0014]

[0015] Structure formula (8), structure formula (9), structure formula (10), structure formula (11),

[0016]

[0017] Structure formula (12), structure formula (13), structure formula (14), structure formula (15),

[0018]

[0019] Structural formula (16), structural formula (17), structural formula (18),

[0020] Here, R3 is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an allyl group, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom; R4 is a hydrogen atom or a methyl group; a is an integer from 0 to 4; b is an integer from 0 to 5; n is any number from 0 to 60; and m and p are each independently any number from 0 to 50. X1 and X2 are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms.

[0021] According to another aspect of the present invention, a method for preparing a polycarbonate oligomer according to the above aspect comprises the following steps. A dissolution step is performed, wherein polycarbonate is dissolved in a solvent, heated to a heating temperature, and stirred to form a first mixture. An addition step is performed, wherein a compound represented by structural formula (II) is added to the first mixture and reacted by maintaining at a heating temperature to form a second mixture:

[0022] Structural formula (II).

[0023] A washing step is performed, whereby the second mixture is cooled and precipitation washed with an alcoholic solvent to form a third mixture. A filtration step is performed, whereby the third mixture is filtered and dried to obtain a polycarbonate oligomer.

[0024] According to another aspect of the present invention, a curable composition is provided. The curable composition comprises a polycarbonate oligomer, an epoxy resin, and a catalyst according to the above aspect, and is mixed at a mixing temperature for sample preparation, wherein the equivalence ratio of the carbonate groups of the polycarbonate oligomer to the epoxy groups of the epoxy resin is 0.5 to 3.0.

[0025] According to another aspect of the present invention, an epoxy crosslinked product is provided. The epoxy crosslinked product is obtained by performing a curing reaction with a curable composition according to the aspect described above.

[0026] According to another aspect of the present invention, a method for degrading an epoxy crosslinked product by aminolysis comprises the following steps. An epoxy crosslinked product according to the above aspect is provided. A degradation step is performed, wherein an aliphatic amine group-containing compound is reacted with the epoxy crosslinked product to degrade the epoxy crosslinked product by aminolysis. Brief explanation of the drawing

[0027] The present invention can be more fully understood by familiarizing oneself with the following detailed description of the embodiments with reference to the attached drawings: FIG. 1 is a flowchart of a method for manufacturing a polycarbonate oligomer according to one embodiment of the present invention. FIG. 2 is a flowchart of a method for manufacturing an epoxy crosslinked product according to another embodiment of the present invention. FIG. 3 is a flowchart of a method for decomposing an epoxy crosslinked product by gaamine decomposition according to another embodiment of the present invention. Figure 4 is of Example 1. 1 This is the H-NMR spectrum. Figure 5 is of Comparative Example 1. 1 This is the H-NMR spectrum. Figure 6 is the FTIR spectrum of Example 1. Figure 7 is the FTIR spectrum of Example 4. Figure 8 is of Example 7 1 This is the H-NMR spectrum. Specific details for implementing the invention

[0028] The present invention will be further illustrated by the following specific embodiments. However, the embodiments may be applied to various concepts of the invention and may be implemented in various specific scopes. The specific embodiments are for illustrative purposes only and are not limited to these practical details.

[0029] In the present invention, the structure of a compound may be represented by a skeletal structural formula, and carbon atoms, hydrogen atoms, and carbon-hydrogen bonds may be omitted from the representation. If functional groups are clearly indicated in the structural formula, their indication is preferred.

[0030] In the present invention, for brevity and smoothness, "polycarbonate oligomer comprising a structure represented by structural formula (I)" may, in some cases, be represented as a polycarbonate oligomer represented by structural formula (I) or a polycarbonate oligomer (I), and other compounds or groups may be represented in the same way.

[0031] Polycarbonate Oligomer

[0032] The present invention provides a polycarbonate oligomer comprising a structure represented by structural formula (I):

[0033] structural formula (I),

[0034] Here, R1 is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an allyl group, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom, and R2 is an alkyl group having 1 to 10 carbon atoms, an ether group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, a structure represented by structural formula (1), structural formula (2), structural formula (3), structural formula (4), structural formula (5), structural formula (6), or structural formula (7):

[0035]

[0036] Structure formula (1), structure formula (2), structure formula (3), structure formula (4), structure formula (5),

[0037]

[0038] Structural formula (6), structural formula (7),

[0039] Here, X is a structure represented by a single bond, structure formula (8), structure formula (9), structure formula (10), structure formula (11), structure formula (12), structure formula (13), structure formula (14), structure formula (15), structure formula (16), structure formula (17) or structure formula (18):

[0040]

[0041] Structure formula (8), structure formula (9), structure formula (10), structure formula (11),

[0042]

[0043] Structure formula (12), structure formula (13), structure formula (14), structure formula (15),

[0044]

[0045] Structure formula (16), structure formula (17), structure formula (18);

[0046] Here, R3 is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an allyl group, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom; R4 is a hydrogen atom or a methyl group; a is an integer from 0 to 4; b is an integer from 0 to 5; n is any number from 0 to 60; and m and p are each independently any number from 0 to 50. X1 and X2 are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms.

[0047] Therefore, the polycarbonate oligomer of the present invention has better processability compared to high molecular weight polycarbonate and has better compatibility with epoxy resin, so it can be used as an epoxy resin curing agent.

[0048] Method for manufacturing polycarbonate oligomer

[0049] Refer to FIG. 1, which is a flowchart of a method (100) for manufacturing a polycarbonate oligomer according to one embodiment of the present invention. In FIG. 1, the method (100) for manufacturing a polycarbonate oligomer includes step (110), step (120), step (130), and step (140).

[0050] In step (110), a dissolution step is performed, wherein polycarbonate is dissolved in a solvent, heated to a heating temperature, and stirred to form a first mixture. Specifically, the solvent is preferably a non-alcoholic or non-amine solvent that has a boiling point higher than 110°C and can dissolve polycarbonate. Accordingly, the solvent of the present invention may be selected from the group consisting of N,N-dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), dimethylformamide (DMF), anisole, dimethyl sulfoxide (DMSO), propylene glycol methyl ether acetate, and propylene glycol methyl ether propionate, and the heating temperature may be 100°C to 180°C, preferably 130°C to 170°C.

[0051] In step (120), an addition step is performed, wherein a compound represented by structural formula (II) is added to the first mixture and reacted by maintaining it at a heating temperature to form a second mixture:

[0052] Structural formula (II).

[0053] The definition of R2 can be found in the paragraph above and is not explained here. Additionally, the molar ratio of the polycarbonate oligomer to the compound represented by structural formula (II) may be 1:10 to 1:90, and preferably 1:40 to 1:70.

[0054] In step (130), a washing step is performed, wherein the second mixture is cooled and precipitated with an alcoholic solvent to form a third mixture. Specifically, the alcoholic solvent may be methanol, ethanol, or isopropyl, but is not limited thereto.

[0055] In step (140), a filtration step is performed, whereby the third mixture is filtered and dried to obtain a powder product, which is a polycarbonate oligomer.

[0056] Curable composition

[0057] The present invention further provides a curable composition comprising the polycarbonate oligomer, epoxy resin, and catalyst described above. The equivalent ratio of the carbonate groups of the polycarbonate oligomer to the epoxy groups of the epoxy resin may be 0.5 to 3.0.

[0058] The epoxy resin described above may be a diglycidyl ether of bisphenol A (DGEBA), a phenol novolac epoxy (PNE), a cresol novolac epoxy (CNE), a dicyclopentadiene-phenol epoxy (DNE), a naphthalene-containing epoxy, a phosphorus epoxy resin, or a mixture thereof. That is, the epoxy resin described above may be used alone or two or more types simultaneously, and if two or more types are used, they may be mixed in any proportion. Thus, by selecting a suitable epoxy resin, the properties required for the subsequent crosslinked product can be imparted.

[0059] The catalyst described above may be selected from the group consisting of 4-dimethylaminopyridine (DMAP), imidazole, 2-methylimidazole, 2-phenylimidazole, and 2-ethyl-4-methylimidazole. Accordingly, the catalyst interacts with the epoxy groups of the epoxy resin to promote a subsequent curing reaction. Specifically, the amount of the catalyst described above added may be 0.05% by weight (% by weight) to 5.0% by weight of the amount of the epoxy resin, and preferably 0.1% by weight to 0.5% by weight.

[0060] Specifically, the curable composition is prepared by mixing a polycarbonate oligomer represented by structural formula (I), an epoxy resin, and a catalyst, and is mixed at a mixing temperature for sample preparation, wherein the mixing temperature may be 90°C to 170°C, preferably 110°C to 140°C. If the temperature is too low, it may cause non-uniform mixing. Conversely, if the temperature is too high, gelation occurs due to the curing reaction, making sample preparation difficult.

[0061] <Epoxy cross-linked product>

[0062] The present invention further provides an epoxy crosslinked product obtained by performing a curing reaction with the curable composition described above. Refer to FIG. 2, which is a flowchart of a method (200) for manufacturing an epoxy crosslinked product according to another embodiment of the present invention, for the curing reaction described above. In FIG. 2, the method (200) for manufacturing an epoxy crosslinked product includes step (210) and step (220).

[0063] In step (210), a mixing step is performed, wherein a polycarbonate oligomer represented by structural formula (I), an epoxy resin, and a catalyst are mixed to obtain a curable composition. Specifically, the polycarbonate oligomer, the epoxy resin, and the catalyst can form a solid prepolymer containing the curable composition by step (210). Detailed information regarding the polycarbonate oligomer, the epoxy resin, and the catalyst may be referenced in the paragraph above and is not described here.

[0064] In step (220), a curing step is performed, wherein a polycarbonate oligomer and an epoxy resin are cross-linked by a catalyst to form an epoxy cross-linked product, wherein the curing reaction is completed by heating the curable composition, and the curing temperature of the curing reaction may be 150°C to 240°C, preferably 170°C to 200°C.

[0065] Method for Degrading Epoxy Crosslinked Products by Gaamine Degradation

[0066] Refer to FIG. 3 for a flowchart of a method (300) for decomposing an epoxy crosslinked product by garamine decomposition according to another embodiment of the present invention. In FIG. 3, the method (300) for decomposing an epoxy crosslinked product by garamine decomposition includes step (310) and step (320).

[0067] In step (310), the above-described epoxy crosslinked product is provided. In step (320), a decomposition step is performed, wherein an aliphatic amine group-containing compound is reacted with the epoxy crosslinked product to decompose the epoxy crosslinked product by amine decomposition.

[0068] In addition, a phenoxy resin represented by structural formula (III) can be obtained by decomposing the above epoxy crosslinking product and washing it with alcohol:

[0069] Structural formula (III),

[0070] The definition of X can be found in the paragraph above and is not explained here. Additionally, Y is a structure represented by a single combination, structure formula (8), structure formula (9), structure formula (10), structure formula (11), structure formula (12), structure formula (13), structure formula (14), structure formula (15), structure formula (16), structure formula (17), structure formula (18) or structure formula (19):

[0071] Structural formula (19).

[0072] The phenoxy resin represented by structural formula (III) is useful for reuse as an auxiliary agent.

[0073] The present invention will be further illustrated through the following specific examples so that a person skilled in the art can fully utilize and practice the invention without excessive interpretation and excessive experimentation. However, the reader should understand that the present invention is not limited to these practical details, that is, these practical details are used only to explain how to implement the materials and methods of the present invention and are not necessarily required.

[0074] <Examples and Comparisons>

[0075] Preparation of Polycarbonate Oligomer

[0076] Example 1: 100g of polycarbonate particles (4×10⁻⁶ -3A polycarbonate oligomer powder (product code PC-122, obtained from CHIMEI Corporation) is mixed with 150 g of N,N-dimethylacetamide solvent, and the temperature is raised to 150°C and maintained while stirring to dissolve the polycarbonate particles in the solvent and form a first mixture. Next, 18.3 g (0.17 mol) of benzyl alcohol is added and reacted for 9 hours to form a second mixture. Then, the second mixture is cooled and poured into methanol to wash and precipitate to form a third mixture, and the third mixture is filtered by suction filtration to obtain a white powder, which is then placed in a vacuum oven at 110°C and dried to obtain the polycarbonate oligomer powder of Example 1, with a yield of 75%. Specifically, the number average molecular weight (Mn) of polycarbonate PC-122 is 24,400, and the weight average molecular weight (Mw) of polycarbonate PC-122 is 45,488. In addition, when the polycarbonate oligomer of Example 1 is measured by gel chromatography permeability (GPC), the number average molecular weight (Mn) and weight average molecular weight (Mw) are 2,391 and 3,532, respectively.

[0077] Example 2: 100g of polycarbonate particles (4.1×10⁻⁶ -3Polycarbonate particles (product code PC-122, obtained from CHIMEI Corporation) are mixed with 150 g of N,N-dimethylacetamide solvent, and the temperature is raised to 150°C and maintained while stirring to dissolve the polycarbonate particles in the solvent to form a first mixture. Next, 27.41 g (0.25 mol) of benzyl alcohol is added and reacted for 9 hours to form a second mixture. Then, the second mixture is cooled and poured into methanol to wash and precipitate to form a third mixture, and the third mixture is filtered by vacuum filtration to obtain a white powder, which is then placed in a vacuum oven at 110°C and dried to obtain the polycarbonate oligomer powder of Example 2, with a yield of 45%. Specifically, the number average molecular weight (Mn) of polycarbonate PC-122 is 24,400, and the weight average molecular weight (Mw) of polycarbonate PC-122 is 45,488. In addition, when the polycarbonate oligomer of Example 2 is measured by gel chromatography permeability (GPC), the number average molecular weight (Mn) and weight average molecular weight (Mw) are 2,163 and 2,747, respectively.

[0078] Example 3: 100g of waste polycarbonate (4.3×10 -3(mol) is mixed with 150g of N,N-dimethylacetamide solvent, and the temperature is raised to 150℃ and maintained while stirring to dissolve the waste polycarbonate in the solvent and form a first mixture. Next, 18.3g (0.17 mol) of benzyl alcohol is added and reacted for 9 hours to form a second mixture. Then, the second mixture is cooled and poured into methanol to wash and precipitate to form a third mixture, and the third mixture is filtered by vacuum filtration to obtain a white powder, which is then placed in a vacuum oven at 110℃ and dried to obtain the polycarbonate oligomer powder of Example 3, with a yield of 78%. Specifically, after measuring by gel chromatography permeability (GPC), the number average molecular weight (Mn) of the waste polycarbonate is 23,512 and the weight average molecular weight (Mw) of the waste polycarbonate is 44,758, whereas the number average molecular weight (Mn) of the polycarbonate oligomer of Example 3 is 3,561 and the weight average molecular weight (Mw) of the polycarbonate oligomer of Example 3 is 5,707.

[0079] Comparative Example 1: 100g of polycarbonate particles (4.1×10⁻⁶ -3Polycarbonate particles (product code PC-122, obtained from CHIMEI Corporation) were mixed with 150g of N,N-dimethylacetamide solvent, and the temperature was raised to 150°C and maintained while stirring to dissolve the polycarbonate particles in the solvent and form a first mixture. Next, 4.58g (0.04 mol) of benzyl alcohol was added and reacted for 9 hours to form a second mixture. Then, the second mixture was cooled and poured into methanol to wash and precipitate to form a third mixture, and the third mixture was filtered by vacuum filtration to obtain a white powder, which was then placed in a vacuum oven at 110°C and dried to obtain the polycarbonate oligomer powder of Comparative Example 1, with a yield of 88%. Specifically, the number average molecular weight (Mn) of polycarbonate PC-122 is 24,400, and the weight average molecular weight (Mw) of polycarbonate PC-122 is 45,488. In addition, when the polycarbonate oligomer of Comparative Example 1 is measured by gel chromatography transmittance (GPC), the number average molecular weight (Mn) and weight average molecular weight (Mw) are 8,798 and 10,777, respectively.

[0080] The reaction schemes of Examples 1 to 3 and Comparative Example 1 are shown in Table 1.

[0081]

[0082] Examples 1 to 3 and Comparative Example 1 are used to verify the structure of Examples 1 to 3 and Comparative Example 1. 1 H-NMR analysis is performed. Referring to FIGS. 4 and FIGS. 5, FIG. 4 is of Example 1. 1 This is the H-NMR spectrum. Figure 5 is of Comparative Example 1. 1 This is the H-NMR spectrum of Examples 2 and 3. 1 The H-NMR spectrum is similar to that of Example 1, so it is not shown here. As shown in FIGS. 4 and 5, the products of Examples 1 to 3 are all polycarbonate oligomers, and the molecular weight of Comparative Example 1 is greater than that of Examples 1 to 3.

[0083] <Preparation of Epoxy Crosslinked Products>

[0084] Example 4: 2g (127.14g / eq) of Example 1 and 2.91g of diglycidyl ether of bisphenol A (product code BE188, obtained from CHANG CHUN PLASTICS CO., LTD.) are mixed in an equivalent ratio of 1, melted at 110°C, and stirred. After mixing, 0.006g of 2-phenylimidazole (0.2wt% of BE188) is added as a catalyst at 90°C, melted uniformly, and stirred to obtain a mixed prepolymer. Subsequently, the mixed prepolymer is placed in an oven at 175°C to cure, and the curing time is set to 30 minutes to obtain the epoxy crosslinked product of Example 4.

[0085] Example 5: 2g (127.14g / eq) of Example 2 and 2.91g of diglycidyl ether of bisphenol A (product code BE188, obtained from CHANG CHUN PLASTICS CO., LTD.) are mixed in an equivalent ratio of 1, melted at 110°C, and stirred. After mixing, 0.006g of 2-phenylimidazole (0.2wt% of BE188) is added as a catalyst at 90°C, and the remaining steps are the same as those of Example 4, and as a result, the epoxy crosslinked product of Example 5 can be obtained.

[0086] Example 6: 2g (127.14g / eq) of Example 3 and 2.91g of diglycidyl ether of bisphenol A (product code BE188, obtained from CHANG CHUN PLASTICS CO., LTD.) are mixed in an equivalent ratio of 1, melted at 110°C, and stirred. After mixing, 0.006g of 2-phenylimidazole (0.2wt% of BE188) is added as a catalyst at 90°C, and the remaining steps are the same as those of Example 4, and as a result, the epoxy crosslinked product of Example 6 can be obtained.

[0087] Comparative Example 2: 2g of polycarbonate (product code PC-122, obtained from CHIMEI Corporation, 127.14g / eq) and 2.91g of diglycidyl ether of bisphenol A (product code BE188, obtained from CHANG CHUN PLASTICS CO., LTD.) were mixed in an equivalent ratio of 1 and melted and stirred at 140°C, but they could not be completely melted and mixed. In addition, 0.006g of 2-phenylimidazole (0.2wt% of BE188) was added as a catalyst at 140°C, but it gelled immediately and could not be mixed smoothly to obtain a prepolymer.

[0088] Comparative Example 3: 2g of polycarbonate (product code PC-122, obtained from CHIMEI Corporation, 127.14g / eq) and 2.91g of diglycidyl ether of bisphenol A (product code BE188, obtained from CHANG CHUN PLASTICS CO., LTD.) were mixed in an equivalent ratio of 1, melted at 140°C, and stirred. After mixing, 0.006g of 4-dimethylaminopyridine (0.2wt% of BE188) was added as a catalyst at 140°C, but it gelled immediately and could not be mixed smoothly to obtain a prepolymer.

[0089] Comparative Example 4: 2 g (127.14 g / eq) of waste polycarbonate and 2.91 g of diglycidyl ether of bisphenol A (product code BE188, obtained from CHANG CHUN PLASTICS CO., LTD.) were mixed in an equivalent ratio of 1, melted at 140°C, and stirred. After mixing, 0.006 g of 2-phenylimidazole (0.2 wt% of BE188) was added as a catalyst at 140°C, but it gelled immediately and could not be mixed smoothly to obtain a prepolymer.

[0090] Comparative Example 5: 2 g (127.14 g / eq) of the polycarbonate oligomer of Comparative Example 1 and 2.91 g of bisphenol A diglycidyl ether (from product code BE188, CHANG CHUN PLASTICS CO., LTD.) (Intake) is mixed in an equivalent ratio of 1, melted at 140°C, and stirred. After mixing, 0.006 g of 2-phenylimidazole (0.2 wt% of BE188) is added as a catalyst at 140°C, but it gels immediately and cannot be mixed smoothly to obtain a prepolymer.

[0091] Comparative Example 6: 2 g of phenol resin (product code PF8110, obtained from CHANG CHUN PLASTICS CO., LTD., 127.14 g / eq) and 2.91 g of diglycidyl ether of bisphenol A (product code BE188, obtained from CHANG CHUN PLASTICS CO., LTD.) are mixed in an equivalent ratio of 1, melted at 140°C, and stirred. After mixing, 0.006 g of 2-phenylimidazole (0.2 wt% of BE188) is added as a catalyst at 90°C, and the remaining steps are the same as those of Example 4, thereby obtaining the epoxy crosslinked product of Comparative Example 6.

[0092] Referring to FIGS. 6 and FIGS. 7, FIG. 6 is the FTIR spectrum of Example 1. FIG. 7 is the FTIR spectrum of Example 4. As shown in FIG. 6, the C=O intrinsic peak of the carbonyl group in the polycarbonate oligomer of Example 1 is 1764 cm⁻¹. -1 It is located at . In addition, as shown in Fig. 7, after curing Example 1 with epoxy resin, the C=O intrinsic peak of the carbonyl group in the epoxy crosslinked product of Example 4 is at 1748 cm⁻¹. -1 It is moved to, which indicates that the carbonyl group is converted from an aromatic carbonate structure to an aliphatic carbonate structure, and the reaction scheme is shown in Table 2.

[0093]

[0094] According to the above results, if Comparative Example 1 and polycarbonate are used as epoxy curing agents, the catalyst can only be added at high temperatures because heating to 140°C to melt and mix will cause the sample block to become solid upon cooling. After adding the catalyst at high temperatures, the reaction will be triggered during the mixing process, which will easily cause the sample block to gel during the process, making it impossible to prepare the sample smoothly. Furthermore, since the molecular weight of the polycarbonate oligomers of Examples 1 to 3 of the present invention is smaller than that of Comparative Example 1 and polycarbonate, the polycarbonate oligomers of Examples 1 to 3 have better mixability during melt mixing, which can be melted and mixed with the epoxy resin at 110°C and still maintain a molten state even after cooling to 90°C. It is advantageous to add a catalyst having a good processing range, and since the curable composition can be completely reacted when cured at 175°C, it can be confirmed that it has good reactivity with the epoxy resin and can be reliably used as an epoxy curing agent. In addition, it can be uniformly mixed under high-temperature melting, possesses specific operability after the addition of the catalyst, and does not gel immediately, thus having a good processing time.

[0095] <Evaluation of Thermal Properties>

[0096] Thermal property evaluation was performed on the epoxy crosslinked products of Examples 4 to 6 and Comparative Example 6, and the thermal property evaluation was performed at a heating rate of 10℃ / min, the glass transition temperature (T g A differential scanning calorimeter (DSC) is used to measure the glass transition temperature (°C), and the measurement results are shown in Table 3.

[0097] Example 4 Example 5 Example 6 Comparative Example 6 T g (℃) 138.9 125.7 139.5 149.4

[0098] As shown in Table 3, the glass transition temperatures of Examples 4 to 6 will vary depending on the molecular weight of the oligomer. Although the performance is slightly worse than the physical properties of epoxy crosslinked products cured by a phenol curing agent, it can still exhibit heat resistance higher than 120°C and can be used in various applications.

[0099] Decomposition of Epoxy Crosslinking Products

[0100] The purpose is to understand the degradability of the epoxy crosslinked product cured by the polycarbonate oligomer of the present invention. First, 0.2 g of the epoxy crosslinked products of Examples 4 to 6 and Comparative Example 6 are each placed in a container containing 4 g of ethanolamine (MEA) and heated in an oven. After the reaction, the ethanolamine is removed to obtain Examples 7 to 9 and Comparative Example 7, in which degradation is complete. Examples 7 to 9 are the results of the degradation reaction of the epoxy crosslinked products of Examples 4 to 6, respectively, and Comparative Example 7 is the result of the degradation reaction of the epoxy crosslinked product of Comparative Example 6. The type of epoxy crosslinked product selected in Examples 7 to 9 and Comparative Example 7, the reaction temperature (°C), the reaction time (hrs), and the residual weight (%) are listed in Table 4.

[0101] Example 7 Example 8 Example 9 Comparative Example 7 Epoxy crosslinked product Example 4 Example 5 Example 6 Comparative Example 6 Reaction temperature 130 130 130 130 Reaction time 24 24 24 24 Residual weight 0 0 0 99

[0102] As shown in Table 4, in Examples 4 to 6, the polycarbonate oligomer of the present invention is used as the epoxy curing agent. When the epoxy crosslinked product formed by the reaction of Examples 4 to 6 and the epoxy resin needs to be decomposed, only an aliphatic amine needs to be added, and the amine decomposition reaction can be carried out by heating. Finally, the epoxy crosslinked product will be completely decomposed, and the residual weight will be 0%. In contrast, Comparative Example 6 uses a phenol resin as the curing agent, and since it has no decomposable properties, the original state of the epoxy crosslinked product is maintained until the end.

[0103] Also, Example 7's 1 Refer to Fig. 8 for the H-NMR spectrum. Example 7 is the result obtained from the decomposition reaction of the epoxy crosslinked product of Example 4 of the present invention and ethanolamine. After the reaction is complete, the excess ethanolamine is removed, washed with ethanol, filtered, and dried to obtain a pale yellow solid product. The pale yellow solid product 1 The results were analyzed by H-NMR and are shown in Fig. 8. The decomposition product after the reaction of the epoxy crosslinking product of Example 4 with ethanolamine is a high-purity phenoxy resin, and the reaction equation is shown in Table 5. In addition, after measuring gel chromatography permeability (GPC), the number average molecular weight (Mn) of the phenoxy resin is 8,391, and the weight average molecular weight (Mw) of the phenoxy resin is 10,612. Therefore, the phenoxy resin can be used as a polyol oligomer for modification or as a coating additive to achieve the goal of complete recycling.

[0104]

[0105] In conclusion, the polycarbonate oligomer of the present invention can be prepared by alcoholizing waste polycarbonate, and this can be used as an epoxy resin curing agent. Additionally, the polycarbonate oligomer of the present invention can be cured after being directly mixed with an epoxy resin. Compared to related technologies, the use of solvents is reduced, and there is a groundbreaking advancement in the epoxy resin melting process. Furthermore, by curing at high temperatures, a high-temperature resistant crosslinked product can be obtained, and the crosslinked product can be completely decomposed by immersing it in an aliphatic amine and heating it. Finally, a high-purity phenoxy resin is obtained, which is expected to return to the product cycle and be used as an additive to achieve the purpose of waste recycling.

[0106] Although the present invention has been described in considerable detail with reference to specific embodiments, other embodiments are possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the embodiments included in this specification.

[0107] It will be apparent to a person skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the present invention. In the foregoing, the present invention is intended to include modifications and variations of the present invention as long as they fall within the scope of the following claims.

Claims

Claim 1 As a polycarbonate oligomer, comprising a structure represented by structural formula (I): Structural formula (I);—wherein R2 is a structure represented by a carbon 1 to 10 alkyl group, a carbon 1 to 10 ether group, a carbon 3 to 6 cycloalkyl group, structural formula (2), structural formula (3), structural formula (4), structural formula (5), structural formula (6) or structural formula (7): Structure formula (2), structure formula (3), structure formula (4), structure formula (5), Structural formula (6), structural formula (7); R1 is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an allyl group, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom, and X is a single bond, a structure represented by structural formula (8), structural formula (9), structural formula (10), structural formula (11), structural formula (12), structural formula (13), structural formula (14), structural formula (15), structural formula (16), structural formula (17) or structural formula (18): Structure formula (8), structure formula (9), structure formula (10), structure formula (11), Structure formula (12), structure formula (13), structure formula (14), structure formula (15), Structural formula (16), structural formula (17), structural formula (18); where R3 is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an allyl group, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom, R4 is a hydrogen atom or a methyl group, a is an integer from 0 to 4, b is an integer from 0 to 5, n is any number from 0 to 60, m and p are each independently any number from 0 to 50, X1 and X2 are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms, where R2 is a structure represented by structural formula (1), A polycarbonate oligomer, wherein R1 is a hydrogen atom, an allyl group, or a halogen atom in structural formula (1), X is a structure represented by structural formula (8), structural formula (9), structural formula (10), structural formula (15), structural formula (16), structural formula (17) or structural formula (18); R3 is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an allyl group, an alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or a halogen atom, a is an integer from 0 to 4, b is an integer from 0 to 5, n is any number from 0 to 60, and X1 and X2 are hydrogen atoms. Claim 2 A method for manufacturing a polycarbonate oligomer of claim 1, comprising: a dissolving step of dissolving a polycarbonate in a solvent, heating to a heating temperature and stirring to form a first mixture; and an adding step of adding a compound represented by structural formula (II) to the first mixture and maintaining at the heating temperature to react to form a second mixture. A method for manufacturing a polycarbonate oligomer comprising: a structural formula (II); a washing step of cooling the second mixture and precipitating and washing with an alcoholic solvent to form a third mixture; and a filtering step of filtering and drying the third mixture to obtain the polycarbonate oligomer. Claim 3 A method for preparing a polycarbonate oligomer according to claim 2, wherein the solvent is selected from the group consisting of N,N-dimethylacetamide, N-methylpyrrolidone, dimethylformamide, anisole, dimethyl sulfoxide, propylene glycol methyl ether acetate, and propylene glycol methyl ether propionate. Claim 4 A method for manufacturing a polycarbonate oligomer according to claim 2, wherein the heating temperature is 100℃ to 180℃. Claim 5 A method for manufacturing a polycarbonate oligomer according to claim 2, wherein the molar ratio of the polycarbonate oligomer to the compound represented by structural formula (II) is 1:10 to 1:

90. Claim 6 A curable composition comprising the polycarbonate oligomer of claim 1, an epoxy resin, and a catalyst, wherein the polycarbonate oligomer, the epoxy resin, and the catalyst are mixed at a mixing temperature for sample preparation, and the equivalence ratio of the carbonate groups of the polycarbonate oligomer to the epoxy groups of the epoxy resin is 0.5 to 3.

0. Claim 7 A curable composition according to claim 6, wherein the catalyst is selected from the group consisting of 4-dimethylaminopyridine, imidazole, 2-methylimidazole, 2-phenylimidazole, and 2-ethyl-4-methylimidazole. Claim 8 A curable composition according to claim 6, wherein the amount of the catalyst added is 0.05% by weight (% by weight) to 5.0% by weight of the amount of the epoxy resin. Claim 9 A curable composition according to claim 6, wherein the mixing temperature is 90°C to 170°C. Claim 10 An epoxy crosslinked product obtained by performing a curing reaction with a curable composition according to paragraph 6. Claim 11 An epoxy crosslinked product according to claim 10, wherein the curable composition is heated to complete the curing reaction, and the curing temperature of the curing reaction is 150°C to 240°C. Claim 12 A method for degrading an epoxy crosslinked product by aminolysis, comprising: a step of performing a degrading step in which an epoxy crosslinked product is degraded by aminolysis by reacting an aliphatic amine group-containing compound with the epoxy crosslinked product of claim 10. Claim 13 In claim 12, the epoxy crosslinking product decomposes to form a phenoxy resin represented by structural formula (III): Structural formula (III);― where Y is a single bond, a structure represented by the above structural formula (8), the above structural formula (9), the above structural formula (10), the above structural formula (11), the above structural formula (12), the above structural formula (13), the above structural formula (14), the above structural formula (15), the above structural formula (16), the above structural formula (17), the above structural formula (18) or the above structural formula (19)― Structural formula (19); method for decomposing epoxy crosslinking products by amine decomposition.

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