Thermoplastic solvent-free two-component polyurethane adhesive and preparation method thereof

Abstract

The invention discloses a thermoplastic solvent-free two-component polyurethane adhesive and a preparation method thereof. The thermoplastic solvent-free two-component polyurethane adhesive comprises polyol, diisocyanate, a catalyst and a chain extender, wherein the diisocyanate is prepared from one or more of diphenylmethane diisocyanate, isophorone diisocyanate, 2, 4-toluene diisocyanate, 2, 6-toluene diisocyanate and hexamethylene diisocyanate, and the diisocyanate is prepared from one or more of diphenylmethane diisocyanate, isophorone diisocyanate, 2, 4-toluene diisocyanate, 2, 6-toluene diisocyanate and hexamethylene diisocyanate; a catalyst includes; the chain extender comprises one or more of 1, 2-propylene glycol, 1, 2-hexanediol, 1, 2-pentanediol, 1, 3-propylene glycol, 1, 6-hexanediol and 1, 10-decanediol; the chain extender comprises one or more of 1, 2-propylene glycol, 1, 2-hexanediol, 1, 2-pentanediol, 1, 3-propylene glycol, 1, 6-hexanediol and 1, 10-decanediol; the polyurethane elastomer is prepared from the following components in parts by weight: 40 to 50 parts of polyol, 35 to 40 parts of diisocyanate, 0.005 part of a catalyst and 10 to 20 parts of a chain extender. The polyurethane adhesive prepared by the invention is convenient to melt and disassemble when devices are recycled.

Description

Technical Field

[0001] The invention belongs to the technical field of adhesives, and in particular relates to a thermoplastic solvent-free two-component polyurethane adhesive and a preparation method thereof. Background Art

[0002] In recent years, with growing environmental awareness, continuous technological advancements, and strong policy support, the new energy vehicle market has experienced explosive growth. New energy vehicles have not only achieved significant technological advancements, such as battery technology innovation and the development of intelligent technology, but have also demonstrated strong growth momentum in terms of market scale and industrial chain integration, becoming a key development direction for the global automotive industry. New energy batteries, as a highly innovative and strategically important key technology in the modern energy sector, play a vital role in the global energy transition and sustainable development. This process generates a large number of discarded power batteries. Disassembling retired power batteries and recovering their valuable materials can effectively conserve resources and protect the environment. However, the excellent stability of the adhesives commonly used in batteries hinders the disassembly and recycling of battery components.

[0003] Polyurethane, an adhesive with excellent bonding properties, plays a crucial role in the development of new energy vehicle power batteries. However, traditional two-component polyurethane adhesives contain large amounts of solvents, which pollute the atmosphere and indoor air. With the introduction of national environmental protection policies and rising public awareness, there is an urgent need to develop new solvent-free two-component adhesives.

[0004] Traditional two-component polyurethane adhesives have excellent bonding properties due to their unique cross-linked structure. However, the presence of the cross-linked structure makes it difficult to melt and disassemble after use. For example, in Chinese patent CN201710822011.1, a two-component polyurethane adhesive and its preparation and application, its unique cross-linked structure effectively enhances the bonding strength of the adhesive. However, this thermoplastic polymer cannot be heated and melted, which hinders the recycling of battery devices.

[0005] Polyurethane hot melt adhesive can be melted by heating, but its melting temperature is relatively high, energy consumption is high and it may cause damage to the device. There is an urgent need to structurally modify the polyurethane to lower its melting temperature and facilitate device disassembly and recycling. Summary of the Invention

[0006] The purpose of this section is to summarize some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of this application to avoid obscuring the purpose of this section, the abstract and the title of the invention, and such simplifications or omissions should not be used to limit the scope of the present invention.

[0007] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0008] Therefore, the object of the present invention is to overcome the deficiencies in the prior art and provide a thermoplastic solvent-free two-component polyurethane adhesive and a preparation method thereof.

[0009] To solve the above technical problems, the present invention provides the following technical solution: a thermoplastic solvent-free two-component polyurethane adhesive, characterized in that it comprises a component A and a component B, wherein the component A is a polyurethane prepolymer and the component B is a chain extender;

[0010] The isocyanate-terminated polyurethane prepolymer is composed of a polyol, a diisocyanate, and a catalyst; the hydroxyl-terminated chain extender includes one or more of 1,2-propylene glycol, 1,2-hexanediol, 1,2-pentanediol, 1,3-propylene glycol, 1,6-hexanediol, and 1,10-decanediol;

[0011] The diisocyanate includes one or more of diphenylmethane diisocyanate, isophorone diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, and hexamethylene diisocyanate; the catalyst includes one of stannous octoate, dibutyltin dilaurate, and zinc-cobalt double metal cyanide catalyst.

[0012] As a preferred embodiment of the thermoplastic solvent-free two-component polyurethane adhesive of the present invention, wherein: based on the mass parts of the raw materials, the polyol is 40-50 parts, the diisocyanate is 35-40 parts, the catalyst is 0.005 parts, and the chain extender is 10-20 parts;

[0013] Epoxy monomers include 2-((2-methoxyethoxy)methyl)ethylene oxide, 2-((2-(2-methoxyethoxy)ethoxy)methyl)ethylene oxide, 2-(2,5,8,11-tetraoxadodecyl)ethylene oxide, and 2-(2,5,8,11,14-pentaoxopentadecyl)ethylene oxide.

[0014] As a preferred embodiment of the thermoplastic solvent-free two-component polyurethane adhesive of the present invention, the preparation method of the polyol includes adding 1,4-butanediol and epoxy monomer into a reaction kettle, reacting with a zinc-cobalt double metal cyanide catalyst, and then separating and purifying.

[0015] As a preferred embodiment of the thermoplastic solvent-free two-component polyurethane adhesive of the present invention, the preparation method of the epoxy monomer includes: stirring epichlorohydrin and sodium hydroxide at room temperature, then dropwise adding ethylene glycol monomethyl ether, after the dropwise addition is completed, filtering the resulting solid-liquid mixture to remove excess sodium hydroxide and sodium chloride generated by the reaction, drying the filtrate with anhydrous magnesium sulfate, further drying with calcium hydride under argon protection, and then vacuum fractionating to obtain the epoxy monomer.

[0016] As a preferred embodiment of the thermoplastic solvent-free two-component polyurethane adhesive of the present invention, the molar ratio of epichlorohydrin to sodium hydroxide is 1:1.

[0017] As a preferred embodiment of the thermoplastic solvent-free two-component polyurethane adhesive of the present invention, the vacuum distillation temperature is 80-120°C.

[0018] As a preferred embodiment of the thermoplastic solvent-free two-component polyurethane adhesive of the present invention, the preparation method of the zinc-cobalt double metal cyanide catalyst includes adding a ZnCl2 aqueous solution to a K3[Co(CN)6] aqueous solution and stirring, precipitating an amorphous precipitate, and then separating, purifying, and drying.

[0019] Another object of the present invention is to overcome the deficiencies in the prior art and provide a method for preparing a thermoplastic solvent-free two-component polyurethane adhesive, characterized in that it comprises reacting a polyol, a diisocyanate, and a catalyst to obtain a product; and mixing the product with a chain extender at room temperature to obtain the thermoplastic solvent-free two-component polyurethane adhesive.

[0020] As a preferred embodiment of the preparation method of the present invention, the reaction temperature is 60-80°C.

[0021] As a preferred embodiment of the preparation method of the present invention, the reaction time is 6 to 12 hours.

[0022] Beneficial effects of the present invention:

[0023] The polyurethane adhesive prepared by the present invention has no solvent addition and no volatile organic matter, thus reducing environmental pollution; the formed linear structure has thermoplasticity, and the introduction of flexible oligoethylene glycol side chains reduces the melting temperature, making it easy to melt and disassemble when recycling devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort. Among them:

[0025] Figure 1 This is the synthetic route of the epoxy monomers of Examples 1 to 8 of the present invention.

[0026] Figure 2 This is the synthesis route of the polyurethane prepolymers of Examples 1 and 5 of the present invention. DETAILED DESCRIPTION

[0027] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0028] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0029] Secondly, the term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive of other embodiments.

[0030] Unless otherwise specified, all raw materials used in the examples of the present invention are commercially available from Hai Aladdin Biochemical Technology Co., Ltd., and their specific product numbers are shown in Table 1.

[0031] Table 1

[0032]

[0033]

[0034] The preparation method for the zinc-cobalt double metal cyanide catalyst used in the specific embodiments of the present invention is as follows: Preparation of DMC Catalyst by Coprecipitation. Under rapid stirring, an aqueous solution of K[Co(CN)] (8 g, 140 mL) and a ZnCl solution (25 g, 40 mL of H2O + 20 mL of t-BuOH) were uniformly added dropwise to a mixed solution (120 mL of H2O + 80 mL of t-BuOH) over 1 hour. After the addition, stirring was continued at room temperature for 1 hour, then the mixture was transferred to a flask and mechanically stirred at 80°C for 3 hours. Finally, the mixture was slurried, washed, dried, and weighed to obtain the zinc-cobalt double metal cyanide (DMC) catalyst.

[0035] Shear strength test: Shear strength is used to indicate the magnitude of initial adhesion. The greater the shear strength, the greater the initial adhesion. After Examples 1-8 were mixed and cured for 60 minutes, shear strength tests were performed according to the relevant methods of standard GB / T 7124-2008.

[0036] Melting temperature test: After 3 days of mixing and curing, the melting temperature was tested using differential calorimetry.

[0037] Example 1

[0038] (1) Preparation of epoxy monomer

[0039] To a 1000ml round-bottom flask, add 92.5g of epichlorohydrin (1.00mol, 1.00equiv.) and 60.0g of sodium hydroxide (1.50mol, 1.5equiv.) and stir uniformly at room temperature. Then, add 76.1g of ethylene glycol monomethyl ether (1.00mol, 1.00equiv.) dropwise. After the addition is complete, the resulting solid-liquid mixture is filtered to remove excess sodium hydroxide and sodium chloride generated by the reaction. The filtrate is dried over anhydrous magnesium sulfate for 6h and then further dried over calcium hydride under argon. The mixture is then fractionally distilled under reduced pressure at 100°C to yield the desired product, 2-((2-methoxyethoxy)methyl)oxirane.

[0040] (2) Preparation of polyols

[0041] 45 parts by weight of 2-((2-methoxyethoxy)methyl)ethylene oxide were added to a reaction kettle, 2 parts by weight of 1,4-butanediol were added, and then 0.5 parts by weight of a zinc-cobalt double metal cyanide catalyst were added. The mixture was reacted at 70° C. for 12 hours, and separated and purified to obtain the target polyol.

[0042] (3) Preparation of component A

[0043] 50 parts by weight of a polyol (molecular weight of 2000, hydroxyl functionality of 2) was placed in a reaction kettle and dehydrated at 110° C. for 2 hours. 36 parts by weight of diphenylmethane diisocyanate, 4 parts by weight of toluene diisocyanate, and 0.005 parts by weight of stannous octoate were then added, and the mixture was stirred at a constant temperature of 75° C. for 1 hour to obtain component A.

[0044] (4) Preparation of component B

[0045] 10 parts by weight of 1,2-butanediol and 10 parts by weight of polyethylene glycol (molecular weight 400) were mixed uniformly at 50° C. and then vacuumed to remove bubbles to obtain component B;

[0046] (5) Preparation of polyurethane adhesive

[0047] The obtained components A and B were mixed evenly for 1 hour to obtain a polyurethane adhesive.

[0048] Example 2

[0049] (1) Preparation of epoxy monomer

[0050] To a 1000 ml round-bottom flask, add 92.5 g of epichlorohydrin (1.00 mol, 1.00 equiv.) and 60.0 g of sodium hydroxide (1.50 mol, 1.5 equiv.) and stir uniformly at room temperature. Then, add 120.2 g of diethylene glycol monomethyl ether (1.00 mol, 1.00 equiv.) dropwise. After the addition is complete, the resulting solid-liquid mixture is filtered to remove excess sodium hydroxide and sodium chloride generated by the reaction. The filtrate is dried over anhydrous magnesium sulfate for 6 h and then further dried over calcium hydride under argon. The mixture is then fractionally distilled under reduced pressure at 100°C to yield the desired product, 2-((2-(2-methoxyethoxy)ethoxy)methyl)oxirane.

[0051] (2) Preparation of polyols

[0052] 45 parts by weight of 2-((2-(2-methoxyethoxy)ethoxy)methyl)ethylene oxide were added to a reaction kettle, 2 parts by weight of 1,4-butanediol were added, and then 0.5 parts by weight of a zinc-cobalt double metal cyanide catalyst were added. The mixture was reacted at 70° C. for 12 hours, and separated and purified to obtain the target polyol.

[0053] (3) Preparation of component A

[0054] 50 parts by weight of a polyol (molecular weight of 2000, hydroxyl functionality of 2) was placed in a reaction kettle and dehydrated at 110° C. for 2 hours. 36 parts by weight of diphenylmethane diisocyanate, 4 parts by weight of toluene diisocyanate, and 0.005 parts by weight of stannous octoate were then added, and the mixture was stirred at a constant temperature of 75° C. for 1 hour to obtain component A.

[0055] (4) Preparation of component B

[0056] 10 parts by weight of 1,2-butanediol and 10 parts by weight of polyethylene glycol (molecular weight 400) were mixed uniformly at 50° C. and then vacuumed to remove bubbles to obtain component B;

[0057] (5) Preparation of polyurethane adhesive

[0058] The obtained components A and B were mixed evenly for 1 hour to obtain a polyurethane adhesive.

[0059] Example 3

[0060] (1) Preparation of epoxy monomer

[0061] To a 1000ml round-bottom flask, add 92.5g of epichlorohydrin (1.00mol, 1.00equiv.) and 60.0g of sodium hydroxide (1.50mol, 1.5equiv.) and stir at room temperature. Then, add 164.2g of triethylene glycol monomethyl ether (1.00mol, 1.00equiv.) dropwise. After the addition is complete, the resulting solid-liquid mixture is filtered to remove excess sodium hydroxide and sodium chloride generated by the reaction. The filtrate is dried over anhydrous magnesium sulfate for 6h and then further dried over calcium hydride under argon. The mixture is then fractionally distilled under reduced pressure at 100°C to yield the desired product, 2-(2,5,8,11-tetraoxadodecyl)oxirane.

[0062] (2) Preparation of polyols

[0063] 45 parts by weight of 2-(2,5,8,11-tetraoxadodecyl)ethylene oxide were added to a reaction kettle, 2 parts by weight of 1,4-butanediol were added, and then 0.5 parts by weight of a zinc-cobalt double metal cyanide catalyst was added. The mixture was reacted at 70° C. for 12 hours, and separated and purified to obtain the target polyol.

[0064] (3) Preparation of component A

[0065] 50 parts by weight of a polyol (molecular weight of 2000, hydroxyl functionality of 2) was placed in a reaction kettle and dehydrated at 110° C. for 2 hours. 36 parts by weight of diphenylmethane diisocyanate, 4 parts by weight of toluene diisocyanate, and 0.005 parts by weight of stannous octoate were then added, and the mixture was stirred at a constant temperature of 75° C. for 1 hour to obtain component A.

[0066] (4) Preparation of component B

[0067] 10 parts by weight of 1,2-butanediol and 10 parts by weight of polyethylene glycol (molecular weight 400) were mixed uniformly at 50° C. and then vacuumed to remove bubbles to obtain component B;

[0068] (5) Preparation of polyurethane adhesive

[0069] The obtained components A and B were mixed evenly for 1 hour to obtain a polyurethane adhesive.

[0070] Example 4

[0071] (1) Preparation of epoxy monomer

[0072] To a 1000ml round-bottom flask, add 92.5g of epichlorohydrin (1.00mol, 1.00equiv.) and 60.0g of sodium hydroxide (1.50mol, 1.5equiv.) and stir at room temperature. Then, add 208.3g of tetraethylene glycol monomethyl ether (1.00mol, 1.00equiv.) dropwise. After the addition is complete, the resulting solid-liquid mixture is filtered to remove excess sodium hydroxide and sodium chloride generated by the reaction. The filtrate is dried over anhydrous magnesium sulfate for 6h and then further dried over calcium hydride under argon. The mixture is then fractionally distilled under reduced pressure at 100°C to yield the desired product, 2-(2,5,8,11,14-pentaoxopentadecyl)oxirane.

[0073] (2) Preparation of polyols

[0074] 45 parts by weight of 2-(2,5,8,11,14-pentaoxapentadecyl)ethylene oxide were added to a reaction kettle, 2 parts by weight of 1,4-butanediol were added, and then 0.5 parts by weight of zinc-cobalt double metal cyanide catalyst were added, and the mixture was reacted at 70° C. for 12 hours, and separated and purified to obtain the target polyol;

[0075] (3) Preparation of component A

[0076] 50 parts by weight of a polyol (molecular weight of 2000, hydroxyl functionality of 2) was placed in a reaction kettle and dehydrated at 110° C. for 2 hours. 36 parts by weight of diphenylmethane diisocyanate, 4 parts by weight of toluene diisocyanate, and 0.005 parts by weight of stannous octoate were then added, and the mixture was stirred at a constant temperature of 75° C. for 1 hour to obtain component A.

[0077] (4) Preparation of component B

[0078] 10 parts by weight of 1,2-butanediol and 10 parts by weight of polyethylene glycol (molecular weight 400) were mixed uniformly at 50° C. and then vacuumed to remove bubbles to obtain component B;

[0079] (5) Preparation of polyurethane adhesive

[0080] The obtained components A and B were mixed evenly for 1 hour to obtain a polyurethane adhesive.

[0081] Example 5

[0082] (1) Preparation of epoxy monomer

[0083] To a 1000ml round-bottom flask, add 92.5g of epichlorohydrin (1.00mol, 1.00equiv.) and 60.0g of sodium hydroxide (1.50mol, 1.5equiv.) and stir uniformly at room temperature. Then, add 76.1g of ethylene glycol monomethyl ether (1.00mol, 1.00equiv.) dropwise. After the addition is complete, the resulting solid-liquid mixture is filtered to remove excess sodium hydroxide and sodium chloride generated by the reaction. The filtrate is dried over anhydrous magnesium sulfate for 6h and then further dried over calcium hydride under argon. The mixture is then fractionally distilled under reduced pressure at 100°C to yield the desired product, 2-((2-methoxyethoxy)methyl)oxirane.

[0084] (2) Preparation of polyols

[0085] 45 parts by weight of 2-((2-methoxyethoxy)methyl)ethylene oxide were added to a reaction kettle, 2 parts by weight of 1,4-butanediol were added, and then 0.5 parts by weight of a zinc-cobalt double metal cyanide catalyst were added. The mixture was reacted at 70° C. for 12 hours, and separated and purified to obtain the target polyol.

[0086] (3) Preparation of component A

[0087] 50 parts by weight of a polyol (molecular weight of 2000, hydroxyl functionality of 2) was placed in a reaction kettle and dehydrated at 110° C. for 2 hours. 32 parts by weight of diphenylmethane diisocyanate, 8 parts by weight of toluene diisocyanate, and 0.005 parts by weight of stannous octoate were then added, and the mixture was stirred at a constant temperature of 75° C. for 1 hour to obtain component A.

[0088] (4) Preparation of component B

[0089] 10 parts by weight of 1,2-butanediol and 10 parts by weight of polyethylene glycol (molecular weight 400) were mixed uniformly at 50° C. and then vacuumed to remove bubbles to obtain component B;

[0090] (5) Preparation of polyurethane adhesive

[0091] The obtained components A and B were mixed evenly for 1 hour to obtain a polyurethane adhesive.

[0092] Example 6

[0093] (1) Preparation of epoxy monomer

[0094] To a 1000 ml round-bottom flask, add 92.5 g of epichlorohydrin (1.00 mol, 1.00 equiv.) and 60.0 g of sodium hydroxide (1.50 mol, 1.5 equiv.) and stir uniformly at room temperature. Then, add 120.2 g of diethylene glycol monomethyl ether (1.00 mol, 1.00 equiv.) dropwise. After the addition is complete, the resulting solid-liquid mixture is filtered to remove excess sodium hydroxide and sodium chloride generated by the reaction. The filtrate is dried over anhydrous magnesium sulfate for 6 h and then further dried over calcium hydride under argon. The mixture is then fractionally distilled under reduced pressure at 100°C to yield the desired product, 2-((2-(2-methoxyethoxy)ethoxy)methyl)oxirane.

[0095] (2) Preparation of polyols

[0096] 45 parts by weight of 2-((2-(2-methoxyethoxy)ethoxy)methyl)ethylene oxide were added to a reaction kettle, 2 parts by weight of 1,4-butanediol were added, and then 0.5 parts by weight of a zinc-cobalt double metal cyanide catalyst were added. The mixture was reacted at 70° C. for 12 hours, and separated and purified to obtain the target polyol.

[0097] (3) Preparation of component A

[0098] 50 parts by weight of a polyol (molecular weight of 2000, hydroxyl functionality of 2) was placed in a reaction kettle and dehydrated at 110° C. for 2 hours. 32 parts by weight of diphenylmethane diisocyanate, 8 parts by weight of toluene diisocyanate, and 0.005 parts by weight of stannous octoate were then added, and the mixture was stirred at a constant temperature of 75° C. for 1 hour to obtain component A.

[0099] (4) Preparation of component B

[0100] 10 parts by weight of 1,2-butanediol and 10 parts by weight of polyethylene glycol (molecular weight 400) were mixed uniformly at 50° C. and then vacuumed to remove bubbles to obtain component B;

[0101] (5) Preparation of polyurethane adhesive

[0102] The obtained components A and B were mixed evenly for 1 hour to obtain a polyurethane adhesive.

[0103] Example 7

[0104] (1) Preparation of epoxy monomer

[0105] To a 1000ml round-bottom flask, add 92.5g of epichlorohydrin (1.00mol, 1.00equiv.) and 60.0g of sodium hydroxide (1.50mol, 1.5equiv.) and stir at room temperature. Then, add 164.2g of triethylene glycol monomethyl ether (1.00mol, 1.00equiv.) dropwise. After the addition is complete, the resulting solid-liquid mixture is filtered to remove excess sodium hydroxide and sodium chloride generated by the reaction. The filtrate is dried over anhydrous magnesium sulfate for 6h and then further dried over calcium hydride under argon. The mixture is then fractionally distilled under reduced pressure at 100°C to yield the desired product, 2-(2,5,8,11-tetraoxadodecyl)oxirane.

[0106] (2) Preparation of polyols

[0107] 45 parts by weight of 2-(2,5,8,11-tetraoxadodecyl)ethylene oxide were added to a reaction kettle, 2 parts by weight of 1,4-butanediol were added, and then 0.5 parts by weight of a zinc-cobalt double metal cyanide catalyst was added. The mixture was reacted at 70° C. for 12 hours, and separated and purified to obtain the target polyol.

[0108] (3) Preparation of component A

[0109] 50 parts by weight of a polyol (molecular weight of 2000, hydroxyl functionality of 2) was placed in a reaction kettle and dehydrated at 110° C. for 2 hours. 32 parts by weight of diphenylmethane diisocyanate, 8 parts by weight of toluene diisocyanate, and 0.005 parts by weight of stannous octoate were then added, and the mixture was stirred at a constant temperature of 75° C. for 1 hour to obtain component A.

[0110] (4) Preparation of component B

[0111] 10 parts by weight of 1,2-butanediol and 10 parts by weight of polyethylene glycol (molecular weight 400) were mixed uniformly at 50° C. and then vacuumed to remove bubbles to obtain component B;

[0112] (5) Preparation of polyurethane adhesive

[0113] The obtained components A and B were mixed evenly for 1 hour to obtain a polyurethane adhesive.

[0114] Example 8

[0115] (1) Preparation of epoxy monomer

[0116] To a 1000ml round-bottom flask, add 92.5g of epichlorohydrin (1.00mol, 1.00equiv.) and 60.0g of sodium hydroxide (1.50mol, 1.5equiv.) and stir at room temperature. Then, add 208.3g of tetraethylene glycol monomethyl ether (1.00mol, 1.00equiv.) dropwise. After the addition is complete, the resulting solid-liquid mixture is filtered to remove excess sodium hydroxide and sodium chloride generated by the reaction. The filtrate is dried over anhydrous magnesium sulfate for 6h and then further dried over calcium hydride under argon. The mixture is then fractionally distilled under reduced pressure at 100°C to yield the desired product, 2-(2,5,8,11,14-pentaoxopentadecyl)oxirane.

[0117] (2) Preparation of polyols

[0118] 45 parts by weight of 2-(2,5,8,11,14-pentaoxapentadecyl)ethylene oxide were added to a reaction kettle, 2 parts by weight of 1,4-butanediol were added, and then 0.5 parts by weight of zinc-cobalt double metal cyanide catalyst were added, and the mixture was reacted at 70° C. for 12 hours, and separated and purified to obtain the target polyol;

[0119] (3) Preparation of component A

[0120] 50 parts by weight of a polyol (molecular weight of 2000, hydroxyl functionality of 2) was placed in a reaction kettle and dehydrated at 110° C. for 2 hours. 32 parts by weight of diphenylmethane diisocyanate, 8 parts by weight of toluene diisocyanate, and 0.005 parts by weight of stannous octoate were then added, and the mixture was stirred at a constant temperature of 75° C. for 1 hour to obtain component A.

[0121] (4) Preparation of component B

[0122] 10 parts by weight of 1,2-butanediol and 10 parts by weight of polyethylene glycol (molecular weight 400) were mixed uniformly at 50° C. and then vacuumed to remove bubbles to obtain component B;

[0123] (5) Preparation of polyurethane adhesive

[0124] The obtained components A and B were mixed evenly for 1 hour to obtain a polyurethane adhesive.

[0125] The test results are shown in Table 2.

[0126] Table 2

[0127] Shear strength / MPa(25℃) Melting temperature (℃) Example 1 4.3 95 Example 2 3.8 90 Example 3 3.3 87 Example 4 2.7 83 Example 5 4.1 93 Example 6 3.7 90 Example 7 3.3 85 Example 8 2.6 78

[0128] As shown in Table 2, the synthesized polyurethane adhesive exhibits excellent bonding properties and a low melting temperature. In Examples 1-4, as the flexible side chains are extended, the adhesive's melting temperature decreases from 95°C to 83°C, while maintaining a shear strength of 2.7 MPa. While the adhesive performance meets the requirements, the reduced melting temperature of the polyurethane adhesive facilitates post-use heating and disassembly of battery devices for recycling.

[0129] Comparative Example 1

[0130] This comparative example differs from Example 1 in that 2-((2-methoxyethoxy)methyl)oxirane is replaced with oxirane, and the rest of the preparation process is the same as that of Example 1 to obtain a polyurethane adhesive.

[0131] Comparative Example 2

[0132] This comparative example differs from Example 2 in that 2-((2-(2-methoxyethoxy)ethoxy)methyl)ethylene oxide is replaced with propylene oxide, and the rest of the preparation process is the same as that of Example 1 to obtain a polyurethane adhesive.

[0133] Table 3

[0134] Shear strength / MPa(25℃) Melting temperature (℃) Comparative Example 1 7.4 143 Comparative Example 2 6.8 137

[0135] Figure 1 This is the synthetic route of the epoxy monomers of Examples 1 to 8 of the present invention. Figure 2 This is the polyurethane prepolymer synthesis route of Examples 1 and 5 of the present invention. As can be seen from Table 3, compared to Examples 1 to 8, Comparative Examples 1 and 2 exhibit good bonding properties due to the lack of flexible side chains, but also exhibit higher melting temperatures, which are not conducive to heating and melting the polyurethane adhesive, resulting in high energy consumption and reduced battery recycling efficiency. Compared with the two-component solvent-free polyurethane adhesive of CN 107118734A and the two-component polyurethane adhesive of CN107459960B and their preparation and application, the polyurethane adhesive designed and synthesized by the present invention has no cross-linked structure and can be disassembled by heating and melting. In addition, the introduction of flexible side chains weakens the interaction between the main chains, reduces the melting temperature, and facilitates the efficient disassembly and recycling of battery devices.

[0136] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, and all of these should be included in the scope of the present invention.

Claims

1. A thermoplastic solvent-free two-component polyurethane adhesive, characterized in that: The invention comprises component A and component B, wherein component A is an isocyanate-terminated polyurethane prepolymer and component B is a hydroxyl-terminated chain extender; The isocyanate-terminated polyurethane prepolymer is composed of a polyol, a diisocyanate, and a catalyst; the hydroxyl-terminated chain extender includes one or more of 1,2-propylene glycol, 1,2-hexanediol, 1,2-pentanediol, 1,3-propylene glycol, 1,6-hexanediol, and 1,10-decanediol; The polyol includes an epoxy monomer, 1,4-butanediol and a zinc-cobalt double metal cyanide catalyst; the diisocyanate includes one or more of diphenylmethane diisocyanate, isophorone diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate and hexamethylene diisocyanate; the catalyst includes one of stannous octoate, dibutyltin dilaurate and a zinc-cobalt double metal cyanide catalyst; Epoxy monomers include 2-((2-methoxyethoxy)methyl)ethylene oxide, 2-((2-(2-methoxyethoxy)ethoxy)methyl)ethylene oxide, 2-(2,5,8,11-tetraoxadodecyl)ethylene oxide, and 2-(2,5,8,11,14-pentaoxopentadecyl)ethylene oxide.

2. The thermoplastic solvent-free two-component polyurethane adhesive according to claim 1, characterized in that: Calculated by weight of the raw materials, the polyol is 40 to 50 parts, the diisocyanate is 35 to 40 parts, the catalyst is 0.005 parts, and the chain extender is 10 to 20 parts.

3. The thermoplastic solvent-free two-component polyurethane adhesive according to claim 1, characterized in that: The preparation method of the polyol comprises the following steps: adding 1,4-butanediol and epoxy monomer into a reaction kettle, reacting with a zinc-cobalt double metal cyanide catalyst, and then separating and purifying the reactants.

4. The thermoplastic solvent-free two-component polyurethane adhesive according to claim 1, characterized in that: The preparation method of the epoxy monomer includes: stirring epichlorohydrin and sodium hydroxide at room temperature, then adding ethylene glycol monomethyl ether dropwise, filtering the obtained solid-liquid mixture after the addition is completed to remove excess sodium hydroxide and sodium chloride generated by the reaction, drying the filtrate with anhydrous magnesium sulfate, further drying with calcium hydride under argon protection, and then reducing the pressure to obtain the epoxy monomer.

5. The thermoplastic solvent-free two-component polyurethane adhesive according to claim 4, characterized in that: The molar ratio of epichlorohydrin to sodium hydroxide is 1:

1.

6. The thermoplastic solvent-free two-component polyurethane adhesive according to claim 4, characterized in that: The vacuum distillation temperature is 80-120°C.

7. The thermoplastic solvent-free two-component polyurethane adhesive according to claim 2, characterized in that: The preparation method of the zinc-cobalt double metal cyanide catalyst comprises the steps of adding a ZnCl2 aqueous solution to a K3[Co(CN)6] aqueous solution, stirring the solution, and precipitating an amorphous precipitate, which is then separated, purified, and dried.

8. The method for preparing the thermoplastic solvent-free two-component polyurethane adhesive according to claims 1 to 7, characterized in that: include, Polyol, diisocyanate and catalyst react to obtain an intermediate product; The intermediate product is mixed with a chain extender at room temperature to obtain a thermoplastic solvent-free two-component polyurethane adhesive.

9. The preparation method according to claim 8, wherein: The reaction temperature is 60-80°C.

10. The preparation method according to claim 9, wherein: The reaction time is 6 to 12 hours.

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