Dispersion agent as well as preparation method and application thereof

Abstract

The invention relates to the technical field of dispergators, and discloses a dispergator and a preparation method and application thereof, the dispergator comprises the following components by mass: 50-100 parts of a penetrant, 50-100 parts of a swelling agent, 10-20 parts of a dispersant, 0.1-1 part of a surfactant A, 0.1-1 part of a surfactant B, and 1-5 parts of a catalyst; the penetrant is composed of methyl formate, ethanol, ethyl acetate, acetone and dichloromethane; the swelling agent is prepared from N-methyl pyrrolidone, dimethyl sulfoxide, tetrahydrofuran, N, N-dimethyl formamide, N, N-dimethyl acetamide, hexamethylphosphoric triamide and xylene. By compounding the penetrating agent, the swelling agent, the dispersing agent, the surfactant and the catalyst, the obtained dispergator can decompose an epoxy resin adhesive at a higher dispergation speed in the process of disassembling the retired battery pack.

Description

Technical Field

[0001] This invention relates to the field of degumming agents, and more specifically, to a degumming agent, its preparation method, and its application. Background Technology

[0002] The new energy vehicle industry is developing rapidly, with a surge in new energy vehicle production and a sharp increase in demand for power batteries. Simultaneously, the number of retired power batteries is also increasing year by year. These retired power batteries contain not only valuable metals such as nickel, cobalt, and manganese, but also toxic and hazardous substances such as lithium hexafluorophosphate and dimethoxyethane. If not properly disposed of, this not only represents a significant waste of resources but also severely pollutes the environment. Driven by factors such as mineral resource shortages, a surge in retired power batteries, and dual-carbon goals, the recycling and reuse of power batteries has become a focal point of policy, market, and technological research and development.

[0003] Battery pack recycling is the reverse process of battery assembly. Currently, the main steps in the industry for battery recycling include unpacking, debinding, and cell crushing and sorting. Among these, the second step, debinding, is the key to recycling efficiency. Battery packs have gone through several technological development stages, including CTM (cell-to-module), CTP (cell-to-pack), CTC (cell-to-chassis), and CTB (cell-to-vehicle). While battery pack safety has improved, the use of large amounts of adhesives, and the claim that there are currently 5,000 to 20,000 types of battery packs, while their mechanical structures are becoming simpler, the amount of polymer adhesives used is increasing, making debinding difficult.

[0004] In the prior art, Chinese patent document CN118562566A discloses a degumming agent for new energy batteries, which comprises the following raw materials in parts by weight: esterified polyvinyl alcohol, 5-10 parts; hydroxyethyl methyl cellulose, 3-7 parts; plant modifier, 5-10 parts; propylene glycol, 8-12 parts; xylene, balance. The plant modifier comprises esterified cellulose, esterified lignin, esterified vegetable oil, and esterified vegetable wax. This invention reduces production costs by adding a plant modifier and also has a certain degumming effect, but it has the following technical problems:

[0005] The degumming agent in the technical solution has a low degumming rate and needs further improvement. The degumming agent provided in Chinese patent document CN118562566A uses esterified polyvinyl alcohol and hydroxyethyl methyl cellulose as its main functional components. Both are high-molecular polymers with long molecular chains and weak diffusion capabilities. When in contact with the battery pack adhesive, they are unable to quickly penetrate into the adhesive layer to destroy the bonding structure. Furthermore, while plant-based modifiers (esterified cellulose, esterified lignin, etc.) can reduce costs, these components have low levels of active groups and insufficient reactivity with the polar groups of the adhesive, failing to quickly initiate key degumming processes such as swelling and degradation of the adhesive layer. Therefore, the degumming agent has a low rate of adhesive degradation.

[0006] The adhesive degreasing agent in the technical solution has poor degreasing effect on epoxy resin adhesives and needs further improvement. Current power battery packs extensively use epoxy resin adhesives. Due to the presence of numerous polar groups such as hydroxyl and ester groups, epoxy resin exhibits strong adhesion to many substances other than non-polar polymers, resulting in the highest adhesive strength and making degreasing difficult. The adhesive degreasing agent provided in Chinese patent document CN118562566A is ineffective in degreasing epoxy resin adhesives. Summary of the Invention

[0007] This invention provides a degumming agent.

[0008] Another object of the present invention is to provide a method for preparing the degumming agent.

[0009] Another object of the present invention is to provide the application of the degumming agent in the recycling of power battery packs.

[0010] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows:

[0011] A degumming agent comprising the following components in parts by weight:

[0012] 50-100 parts of penetrant

[0013] 50-100 parts of swelling agent

[0014] 10-20 parts of dispersant

[0015] Surfactant A 0.1-1 part,

[0016] Surfactant B 0.1-1 part,

[0017] 1-5 parts catalyst;

[0018] The penetrant is composed of methyl formate, ethanol, ethyl acetate, acetone and dichloromethane;

[0019] The swelling agent is composed of N-methylpyrrolidone, dimethyl sulfoxide, tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, hexamethylphosphoric triamine, and xylene;

[0020] The dispersant is composed of methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, and ethyl acetate.

[0021] The surfactant A is selected from polyethylene glycol, polyoxyethylene ether, and polysorbate;

[0022] The surfactant B is selected from sodium dodecyl sulfate and sodium dodecylbenzene sulfonate.

[0023] Preferably, the catalyst is selected from one or more of the following: cerium oxide-supported nickel-palladium bimetallic catalyst Ni-Pd / CeO2, cerium ammonium nitrate, and acetic acid.

[0024] In the cerium oxide-supported nickel-palladium bimetallic catalyst Ni-Pd / CeO2 described in this invention, the loading amounts of nickel and palladium are 5-10 wt% and 2-5 wt%, respectively.

[0025] Preferably, the mass ratio of methyl formate, ethanol, ethyl acetate, acetone and dichloromethane in the penetrant is (2-3):(3-6):(2-3):(5-8):(4-6).

[0026] Preferably, the mass ratio of N-methylpyrrolidone, dimethyl sulfoxide, tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, hexamethylphosphoric triamine, and xylene in the swelling agent is (4-8):(2-6):(2-6):(3-7):(2-4):(4-8):(3-6).

[0027] Preferably, the mass ratio of methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, and ethyl acetate in the dispersant is (2-6):(3-7):(3-6).

[0028] Preferably, the average molecular weight of the polyethylene glycol in surfactant A is 190 to 210.

[0029] The number of additions of ethylene oxide (EO) to the polyoxyethylene ether in surfactant A of the present invention is 20;

[0030] The average degree of polymerization of the polyoxyethylene chain in the polysorbate molecule of surfactant A in this invention is 20.

[0031] This invention also provides a method for preparing the deflocculant described in any one of the above claims, comprising the following steps:

[0032] S1. Add each component in proportion and mix evenly to obtain penetrant, swelling agent and dispersant respectively;

[0033] S2. First, add the penetrant and stir until homogeneous. Then, add the swelling agent and dispersant and stir until homogeneous to obtain mixture A.

[0034] S3. Add surfactant A, surfactant B and catalyst to mixture A, stir until homogeneous, and obtain the degumming agent.

[0035] The present invention also provides the application of the degumming agent described in any of the above claims in the recycling of power battery packs.

[0036] Preferably, the application specifically refers to the use of a debinding agent in the degradation of adhesives in power battery packs.

[0037] More preferably, the adhesive is epoxy resin.

[0038] The degumming agent described in this invention has the following beneficial effects:

[0039] This invention provides a degumming agent for disassembling epoxy resin adhesives in retired battery packs and its preparation method. This invention prepares a degumming agent with a fast degradation rate of epoxy resin adhesives by compounding a penetrant, a swelling agent, a dispersant, a surfactant and a catalyst.

[0040] Wherein: The solvent molecules of the penetrant of the present invention are small, and at the same reaction temperature, their molecular mobility is strong, thus possessing stronger penetrating ability. They can enter the interior of the adhesive layer through some tiny gaps. While the small molecules of the penetrant enter the interior of the adhesive, they can also pave the way for swelling agents, dispersants, and catalysts, bringing these functional additives into the interior of the adhesive layer together, thereby enabling them to perform their respective functions and achieve debinding.

[0041] Swelling agents have strong molecular polarity, which can effectively disrupt the interaction between polar groups such as hydroxyl groups in the adhesive molecules at the bonding interface and the various structural parts of the battery pack, such as the oxides on the surface of metallic aluminum and the PET blue film, thereby causing adhesive failure. Mechanistically, this belongs to the type of adhesive failure, namely adhesion failure or interface failure. Therefore, swelling agents with good dissolving ability also play an important role in the debonding process.

[0042] Methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, and ethyl acetate in the dispersant are ester solvents with good compatibility. In the descaling agent, they utilize the principle of "like dissolves like" to improve the solubility of epoxy resin, thereby dispersing the epoxy resin and facilitating the removal of the adhesive.

[0043] Both surfactants A and B can reduce the surface tension of the desiccant, thereby giving the desiccant good wetting and penetrating ability. The interaction between the desiccant and the adhesive molecules is also enhanced, thus increasing the desiccant rate.

[0044] Catalysts play a crucial role in the depolymerization of epoxy resin adhesives by lowering the activation energy and promoting the degradation of epoxy resin. Specifically, acetic acid induces acetylation in epoxy resins. Acetylation simultaneously breaks ether and CN bonds, efficiently depolymerizing aliphatic and aromatic epoxy amine thermosetting materials, converting amines into the corresponding acetamide forms. This disrupts the cross-linked structure of the epoxy resin, rendering it insoluble and infusible, thus promoting its dissolution. Mechanistically, this falls under the category of cohesive failure in adhesive failure. Furthermore, the other two catalysts described in this invention also exhibit similar catalytic effects, degrading epoxy resins and achieving rapid depolymerization. The cerium oxide-supported nickel-palladium bimetallic catalyst (Ni-Pd / CeO2) is prepared using nickel chloride and palladium chloride as metal precursors via sodium hydroxide co-precipitation. After depolymerization, cerium ammonium nitrate is reduced and recycled into a high-value-added catalyst—cerium ammonium nitrate tetrahydrate.

[0045] The degumming agent of this invention is composed of a penetrant, swelling agent, dispersant, surfactant, and catalyst. On one hand, it comprehensively covers the degumming mechanism, including molecular penetration, disruption of molecular interactions at the adhesive interface, destruction of cross-linked structures, reduction of surface energy to promote penetration and wetting, and the principle of "like dissolves like," resulting in significant effects. On the other hand, the raw materials used in the preparation of the degumming agent are diverse, with good compatibility among the components and good overall stability. Because it is an organic solvent, its low conductivity also effectively prevents accidents caused by battery pack discharge leakage. Therefore, the degumming agent prepared in this invention for disassembling epoxy resin adhesives in automotive battery packs has a fast degumming rate and good compatibility, exhibiting superior technical effects compared to existing technologies. Detailed Implementation

[0046] To enable those skilled in the art to better understand the present invention, the present invention will now be further described in conjunction with specific embodiments.

[0047] In the following description, the embodiments of this application are for illustrative purposes and not for limiting purposes, so as to provide a thorough understanding of the embodiments. However, those skilled in the art will understand that the embodiments of this application can also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known preparation methods have been omitted so as not to obscure the description of the embodiments of this application with unnecessary details. Unless otherwise specified, the raw materials used in the following embodiments and comparative examples are all commercially available.

[0048] It should also be understood that the term "and / or" as used in the specification of embodiments of this application and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations. The terms "comprising," "including," "containing," "having," and variations thereof all mean "including but not limited to," unless otherwise specifically emphasized. "A plurality" means two or more.

[0049] This section only introduces content related to the inventive points; other details can be obtained from relevant technologies and will not be described in detail here. The following embodiments only illustrate several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of protection of this application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. Therefore, the scope of protection of this patent application should be determined by the appended claims. The invention will be further described in detail below with reference to specific embodiments.

[0050] The raw materials used in all embodiments and comparative examples of this invention are commercially available, and some of these raw materials are sourced as follows:

[0051] Methyl formate was purchased from Saen Chemical Technology Co., Ltd. / Shanghai Runjie Chemical Reagent Co., Ltd.

[0052] Ethyl acetate was purchased from Saen Chemical Technology Co., Ltd.

[0053] N,N-Dimethylformamide was purchased from Saen Chemical Technology Co., Ltd.

[0054] Dichloromethane was purchased from Saen Chemical Technology Co., Ltd.

[0055] Isopropanol was purchased from Shanghai Runjie Chemical Reagent Co., Ltd.

[0056] Ethyl 3-ethoxypropionate was purchased from Saen Chemical Technology Co., Ltd.

[0057] Tetrahydrofuran was purchased from Shanghai Runjie Chemical Reagent Co., Ltd.

[0058] N,N-Dimethylacetamide was purchased from Saen Chemical Technology Co., Ltd.

[0059] Hexamethylphosphoric acid triamine was purchased from Chengdu Kelong Chemical Co., Ltd.

[0060] 3-Methoxypropionate methyl ester was purchased from Zhongshan Dixin Chemical Co., Ltd.

[0061] Xylene was purchased from Saen Chemical Technology Co., Ltd.

[0062] N-methylpyrrolidone was purchased from Saen Chemical Technology Co., Ltd.

[0063] Dimethyl sulfoxide was purchased from Saen Chemical Technology Co., Ltd.

[0064] Sodium dodecyl sulfate was purchased from Saen Chemical Technology Co., Ltd.

[0065] Sodium dodecylbenzenesulfonate was purchased from Saen Chemical Technology Co., Ltd.

[0066] Polysorbate 20 was purchased from Shanghai Runjie Chemical Reagent Co., Ltd.

[0067] Polyethylene glycol 200 was purchased from Shanghai Maclean Biochemical Technology Co., Ltd.

[0068] Polyoxyethylene ether 20 was purchased from Shanghai Maclean Biochemical Technology Co., Ltd.

[0069] Glacial acetic acid was purchased from Saen Chemical Technology Co., Ltd.

[0070] Cerium ammonium nitrate was purchased from Shanghai Maclean Biochemical Technology Co., Ltd.

[0071] Example 1

[0072] A degumming agent is composed of the following components: 100g of penetrant, 100g of swelling agent, 20g of dispersant, 1g of surfactant A, 1g of surfactant B, and 5g of catalyst;

[0073] The penetrant is composed of methyl formate, ethanol, ethyl acetate, acetone and dichloromethane, with the mass ratio of each component being 3:5:2:6:4.

[0074] The swelling agent is composed of N-methylpyrrolidone, dimethyl sulfoxide, tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, hexamethylphosphoric triamine, and xylene in a mass ratio of 4:2:2:3:2:4:3.

[0075] The dispersant is composed of methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, and ethyl acetate in a mass ratio of 3:3:4.

[0076] The surfactant A is polyethylene glycol with a molecular weight of 200, and the surfactant B is sodium dodecyl sulfate;

[0077] The catalyst is acetic acid.

[0078] The method for preparing the degumming agent includes the following steps:

[0079] S1. Add each component according to the proportion and mix thoroughly to obtain the penetrant, swelling agent and dispersant, as follows:

[0080] S11. Preparation of penetrant: Add 15g methyl formate, 10g ethyl acetate, 30g acetone and 20g dichloromethane to 25g ethanol, mix well to obtain penetrant;

[0081] S12. Preparation of swelling agent: Add 10g dimethyl sulfoxide, 10g tetrahydrofuran, 15g N,N-dimethylformamide, 10g N,N-dimethylacetamide, 20g hexamethylphosphoric triamine, and 15g xylene to 20g N-methylpyrrolidone, stir evenly to obtain the swelling agent;

[0082] S13. Preparation of dispersant: Add 6g of methyl 3-methoxypropionate and 6g of ethyl 3-ethoxypropionate to 8g of ethyl acetate, mix well to obtain a dispersant;

[0083] S2. Mix the 100g penetrant obtained in step S11, the 100g swelling agent obtained in step S12, and the 20g dispersant obtained in step S13 evenly to obtain mixture A;

[0084] S2. First, add 1g sodium dodecyl sulfate and 1g polyethylene glycol 200 to the mixed solvent and mix well to obtain mixture B; then, add 5g acetic acid to mixture B and stir well to obtain the degumming agent.

[0085] Example 2

[0086] This embodiment is the second embodiment of the present invention. Unlike embodiment 1, the surfactant A is 1g of polyoxyethylene ether 20, and the addition number of ethylene oxide (EO) in the polyoxyethylene ether is 20; the surfactant B is 1g of sodium dodecylbenzenesulfonate; and the catalyst is 5g of cerium oxide-supported nickel-palladium bimetallic catalyst (Ni-Pd / CeO2), wherein the loading of nickel and palladium in the catalyst is 8wt% and 2wt%, respectively.

[0087] Example 3

[0088] This embodiment is the third embodiment of the present invention. The difference from embodiment 1 is that the surfactant A is 1g of polysorbate 20, and the average degree of polymerization of the polyoxyethylene chain in the polysorbate molecule is 20; the surfactant B is 1g of sodium dodecyl sulfate; and the catalyst is 5g of cerium ammonium nitrate.

[0089] Example 4

[0090] This embodiment is the fourth embodiment of the present invention. The difference from embodiment 1 is that the surfactant A is 1g of polysorbate 20, and the average degree of polymerization of the polyoxyethylene chain in the polysorbate molecule is 20; the surfactant B is 1g of sodium dodecyl sulfate; and the catalyst is 5g of acetic acid.

[0091] Example 5

[0092] This embodiment is the fifth embodiment of the present invention. The difference from embodiment 1 is that the surfactant A is polyethylene glycol with a molecular weight of 200; the surfactant B is 1g of sodium dodecylbenzenesulfonate; and the catalyst is 5g of cerium ammonium nitrate.

[0093] Example 6

[0094] This embodiment is the sixth embodiment of the present invention. The difference from embodiment 1 is that the penetrant is 80g, the swelling agent is 80g, the dispersant is 15g, the surfactant A is 0.5g, the surfactant B is 0.5g, and the catalyst is 3g.

[0095] The penetrant is composed of methyl formate, ethanol, ethyl acetate, acetone and dichloromethane, with a mass ratio of 2.5:4.5:2.5:6:5.

[0096] The swelling agent is composed of N-methylpyrrolidone, dimethyl sulfoxide, tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, hexamethylphosphoric triamine, and xylene in a mass ratio of 6:4:4:5:3:6:4.5.

[0097] The dispersant is composed of methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, and ethyl acetate in a mass ratio of 4.5:5:5.

[0098] Example 7

[0099] This embodiment is the 7th embodiment of the present invention. Unlike embodiment 1, the degumming agent is composed of the following components: 50g of penetrant, 100g of swelling agent, 10g of dispersant, 0.1g of surfactant A, 0.1g of surfactant B, and 1g of catalyst.

[0100] The penetrant is composed of methyl formate, ethanol, ethyl acetate, acetone and dichloromethane, with the mass ratio of each component being 2:6:2:5:4.

[0101] The swelling agent is composed of N-methylpyrrolidone, dimethyl sulfoxide, tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, hexamethylphosphoric triamine, and xylene in a mass ratio of 4:6:2:3:2:4:3.

[0102] The dispersant is composed of methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, and ethyl acetate in a mass ratio of 2:7:3.

[0103] The average molecular weight of the polyethylene glycol in surfactant A is 190;

[0104] The catalyst was a 5g cerium oxide-supported nickel-palladium bimetallic catalyst (Ni-Pd / CeO2), wherein the loadings of nickel and palladium in the catalyst were 5wt% and 5wt%, respectively.

[0105] Example 8

[0106] This embodiment is the 8th embodiment of the present invention. Unlike embodiment 1, the degumming agent is composed of the following components: 100g of penetrant, 50g of swelling agent, 20g of dispersant, 1g of surfactant A, 1g of surfactant B, and 5g of catalyst.

[0107] The penetrant is composed of methyl formate, ethanol, ethyl acetate, acetone and dichloromethane, with the mass ratio of each component being 3:3:3:8:6.

[0108] The swelling agent is composed of N-methylpyrrolidone, dimethyl sulfoxide, tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, hexamethylphosphoric triamine, and xylene in a mass ratio of 8:2:6:7:4:8:6.

[0109] The dispersant is composed of methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, and ethyl acetate in a mass ratio of 6:3:6.

[0110] The average molecular weight of the polyethylene glycol in surfactant A is 210;

[0111] The catalyst was a nickel-palladium bimetallic catalyst (Ni-Pd / CeO2) supported on 5g of cerium oxide, wherein the loadings of nickel and palladium in the catalyst were 10wt% and 2wt%, respectively.

[0112] Comparative Example 1

[0113] This comparative example is the first comparative example of the present invention. Unlike Example 6, no penetrant was added to the degumming agent component or during the preparation process.

[0114] Comparative Example 2

[0115] This comparative example is the second comparative example of the present invention. Unlike Example 6, no swelling agent was added to the degumming agent component or during the preparation process.

[0116] Comparative Example 3

[0117] This comparative example is the third comparative example of the present invention. Unlike Example 6, no dispersant was added to the degumming agent component or during the preparation process.

[0118] Comparative Example 4

[0119] This comparative example is the fourth comparative example of the present invention. Unlike Example 6, no surfactants A and B were added to the degumming agent component or during the preparation process.

[0120] Comparative Example 5

[0121] This comparative example is the fifth comparative example of the present invention. Unlike Example 6, no catalyst was added to the degumming agent component or during the preparation process.

[0122] Comparative Example 6

[0123] This comparative example is the sixth comparative example of the present invention. Unlike Example 6, no surfactant A was added to the degumming agent component or during the preparation process.

[0124] Comparative Example 7

[0125] This comparative example is the 7th comparative example of the present invention. Unlike Example 6, no surfactant B was added to the degumming agent component or during the preparation process.

[0126] Performance testing:

[0127] According to GB / T 7124-2008, bonding standard samples of epoxy resin adhesives were prepared. These standard samples were soaked and debonded using the debonding agents prepared in Examples 1-8 and Comparative Examples 1-7, respectively. Five samples were soaked in each group, and the average initial shear strength and the average shear strength after 8 hours of debonding were recorded. The debonding agents prepared in Examples 1-8 and Comparative Examples 1-7 were applied to the disassembly of epoxy resin adhesives in retired battery packs. The debonding performance test results are shown in Table 1.

[0128] Table 1. Degreasing properties of the degreasing agents obtained in Examples 1-8 and Comparative Examples 1-7

[0129] project Initial shear strength (MPa) Strength (MPa) after 8 hours of debonding Example 1 13.5 2.26 Example 2 13.3 2.02 Example 3 13.6 2.43 Example 4 13.9 3.34 Example 5 12.7 1.93 Example 6 12.8 1.61 Example 7 13.5 3.51 Example 8 13.8 3.49 Comparative Example 1 12.9 11.6 Comparative Example 2 13.2 9.89 Comparative Example 3 13.5 7.53 Comparative Example 4 12.8 6.30 Comparative Example 5 13.4 11.8 Comparative Example 6 13.3 5.1 Comparative Example 7 13.5 5.7

[0130] As can be seen from Table 1, the degumming agent prepared by this invention can decompose epoxy resin adhesives at a faster degumming speed during the disassembly of retired battery packs. This is because:

[0131] (1) The solvent molecules of the penetrant are small and have strong molecular mobility at the same reaction temperature. Therefore, they have stronger penetrating ability and can enter the interior of the adhesive layer through some tiny gaps. While the small molecules of the penetrant enter the interior of the adhesive, they can also open up the way for the swelling agent, dispersant and catalyst, and bring these functional additives into the interior of the adhesive layer together, thereby enabling them to perform their respective functions and achieve degumming.

[0132] (2) The swelling agent has strong molecular polarity, which can effectively destroy the interaction between the polar groups such as hydroxyl groups in the adhesive molecules at the bonding interface and the structure of various parts of the battery pack, such as the oxides on the surface of aluminum metal and the PET blue film, thereby causing bonding failure. In terms of mechanism, it belongs to the adhesion failure or interface failure in the adhesive failure type.

[0133] (3) Methyl 3-methoxypropionate, ethyl 3-ethoxypropionate and ethyl acetate in the dispersant are ester solvents with good compatibility. They utilize the principle of "like dissolves like" in the descaling agent to improve the solubility of epoxy resin and play a role in dispersing epoxy resin, thereby helping to remove the glue.

[0134] (4) Both surfactant A and surfactant B can reduce the surface tension of the desiccant, thus giving the desiccant good wetting ability and penetration. The interaction between the desiccant and the adhesive molecules is also enhanced, and the desiccant rate is improved.

[0135] (5) Catalysts play a crucial role in the depolymerization of epoxy resin adhesives by lowering the activation energy and promoting the degradation of epoxy resin. Specifically, acetic acid induces acetylation of epoxy resin, and acetylation can simultaneously break ether and CN bonds, efficiently depolymerizing aliphatic and aromatic epoxy amine thermosetting materials, converting amines into the corresponding acetamide forms. This disrupts the cross-linking structure of the epoxy resin, rendering it "infusible and insoluble," thus promoting its dissolution. Mechanistically, this belongs to the cohesive failure type of adhesive failure. Besides acetic acid, cerium oxide-supported nickel-palladium bimetallic catalysts Ni-Pd / CeO2 and cerium ammonium nitrate also exhibit similar catalytic effects, degrading epoxy resin and achieving rapid depolymerization.

[0136] Comparative Example 1, which did not add a penetrant during the preparation of the epoxy resin adhesive degumming agent for dismantling retired battery packs, exhibited a slower degumming rate, as shown in Table 1. This is because the solvent molecules of the penetrant are small, and at the same reaction temperature, their molecular mobility is strong, thus possessing stronger penetrating power. They can enter the adhesive layer through some tiny gaps. While the small molecules of the penetrant enter the adhesive layer themselves, they can also pave the way for swelling agents, dispersants, and catalysts, bringing these functional additives into the adhesive layer along with them, thereby enabling them to perform their respective functions and achieve degumming. Therefore, Comparative Example 1 showed a slower degumming rate than Example 1.

[0137] Comparative Example 2 did not add a swelling agent during the preparation of the epoxy resin adhesive degreasing agent in the disassembly of the retired battery pack. As can be seen from Table 1, its degreasing rate was slower. This is because the swelling agent has strong molecular polarity and can effectively destroy the interaction between the polar groups such as hydroxyl groups in the adhesive molecules at the bonding interface and the various structural parts of the battery pack, such as the oxides on the surface of the aluminum metal and the PET blue film, thereby causing adhesive failure. In terms of mechanism, it belongs to the adhesive failure or interface failure type in adhesive failure. Therefore, the degreasing rate of Comparative Example 2 is slower than that of Example 1.

[0138] Comparative Example 3, since no dispersant was added during the preparation of the degumming agent for the epoxy resin adhesive in the disassembled retired battery pack, showed a slower degumming rate as shown in Table 1. This is because methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, and ethyl acetate in the solvent are ester solvents with good compatibility. In the degumming agent, the principle of "like dissolves like" is used to improve the solubility of the epoxy resin and disperse the epoxy resin, thereby facilitating the removal of the adhesive. Therefore, the degumming rate of Comparative Example 3 was slower than that of Example 1.

[0139] Comparative Example 4, since no surfactant was added during the preparation of the descaling agent for the epoxy resin adhesive in the disassembled retired battery pack, showed a slower descaling rate as shown in Table 1. This is because both surfactants A and B can reduce the surface tension of the descaling agent, thereby giving the descaling agent good wetting ability and penetration. The interaction force between the descaling agent and the adhesive molecules is also enhanced, thus increasing the descaling rate. Therefore, Comparative Example 4 showed a slower descaling rate than Example 1.

[0140] Comparative Example 5, lacking a catalyst in the preparation of the depolymerizing agent for the epoxy resin adhesive in the disassembled retired battery pack, exhibited a slower depolymerization rate, as shown in Table 1. This is because the catalyst, by lowering the activation energy, promotes the degradation of the epoxy resin, playing a crucial role in the depolymerization process. Acetic acid induces acetylation in the epoxy resin, and acetylation simultaneously breaks ether and CN bonds, efficiently depolymerizing aliphatic and aromatic epoxy amine thermosetting materials, converting amines into the corresponding acetamide forms. This disrupts the cross-linked structure of the epoxy resin, rendering it "infusible and insoluble," thus promoting its dissolution. Mechanistically, this falls under the category of cohesive failure in adhesive failure. Besides acetic acid, the other two catalysts mentioned also possess similar catalytic effects, degrading the epoxy resin and achieving rapid depolymerization. Therefore, Comparative Example 5 exhibits a slower depolymerization rate than Example 1.

[0141] The above description is merely an embodiment of the present invention and does not limit the scope of patent protection. Any non-substantial changes or substitutions made by those skilled in the art based on the present invention will still fall within the scope of patent protection.

Claims

1. A degumming agent, characterized in that, Contains the following components by weight: 50-100 parts of penetrant 50-100 parts of swelling agent 10-20 parts of dispersant Surfactant A 0.1-1 part, Surfactant B 0.1-1 part, 1-5 parts catalyst; The penetrant is composed of methyl formate, ethanol, ethyl acetate, acetone and dichloromethane; The swelling agent is composed of N-methylpyrrolidone, dimethyl sulfoxide, tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, hexamethylphosphoric triamine, and xylene; The dispersant is composed of methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, and ethyl acetate. The surfactant A is selected from polyethylene glycol, polyoxyethylene ether, and polysorbate; The surfactant B is selected from sodium dodecyl sulfate and sodium dodecylbenzene sulfonate.

2. The degumming agent according to claim 1, characterized in that, The catalyst is selected from one or more of the following: cerium oxide-supported nickel-palladium bimetallic catalyst Ni-Pd / CeO2, cerium ammonium nitrate, and acetic acid.

3. The degumming agent according to claim 1, characterized in that, The mass ratio of methyl formate, ethanol, ethyl acetate, acetone and dichloromethane in the penetrant is (2-3):(3-6):(2-3):(5-8):(4-6).

4. The degumming agent according to claim 1, characterized in that, The swelling agent contains N-methylpyrrolidone, dimethyl sulfoxide, tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, hexamethylphosphoric triamine, and xylene in a mass ratio of (4-8):(2-6):(2-6):(3-7):(2-4):(4-8):(3-6).

5. The degumming agent according to claim 1, characterized in that, The mass ratio of methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, and ethyl acetate in the dispersant is (2-6):(3-7):(3-6).

6. The degumming agent according to claim 1, characterized in that, The average molecular weight of the polyethylene glycol in surfactant A is 190–210.

7. A method for preparing the degumming agent according to any one of claims 1 to 6, characterized in that, Includes the following steps: S1. Add each component in proportion and mix evenly to obtain penetrant, swelling agent and dispersant respectively; S2. First, add the penetrant and stir until homogeneous. Then, add the swelling agent and dispersant and stir until homogeneous to obtain mixture A. S3. Add surfactant A, surfactant B and catalyst to mixture A, stir until homogeneous, and obtain the degumming agent.

8. The application of the degumming agent as described in any one of claims 1 to 6 in the recycling of power battery packs.

9. The application of the degumming agent according to claim 8 in the recycling of power battery packs, characterized in that, The debinding agent is used in the degradation of adhesives in power battery packs.

10. The application of the degumming agent according to claim 9 in the recycling of power battery packs, characterized in that, The adhesive is epoxy resin.