Preparation method of low-temperature composite adhesive for high-elasticity composite adhesive tape

Abstract

The invention discloses a preparation method of a low-temperature composite adhesive for a high-elasticity composite adhesive tape, and relates to the technical field of adhesives. The preparation method of the low-temperature composite adhesive comprises the following steps: reacting polycaprolactone glycol with diisocyanate to obtain a prepolymer; then carrying out a reaction on a chain extender and an isocyanate group in the prepolymer to obtain a pre-product; and finally, compounding the pre-product with a plasticizer and an antioxidant to obtain the low-temperature composite adhesive. The low-temperature composite adhesive prepared by the invention is unique in structure, excellent in elasticity and low-temperature resistance and relatively high in viscosity, and has wide application potential.

Description

Technical Field

[0001] The present application relates to the technical field of adhesives, and in particular to a method for preparing a low-temperature composite adhesive for a high-elastic composite tape. Background Art

[0002] Low-temperature composite adhesive is an adhesive that can maintain good bonding performance at relatively low temperatures. Its development history can be traced back to the mid-20th century. Initially, in order to meet the demand for high-performance materials in high-tech fields such as aerospace, researchers began to explore adhesives that can maintain stable performance in extreme environments. With the advancement of science and technology and the improvement of processes, low-temperature composite adhesives have gradually moved from the aerospace field to medical devices, automotive industry, electronics industry, cryogenic equipment and other fields.

[0003] Among them, polyurethane low-temperature adhesives stand out from many commercial rubbers and plastics because of their excellent comprehensive mechanical properties, as well as excellent wear resistance, oil resistance and aging resistance, etc., and have attracted widespread attention. However, at the same time, in some specific low-temperature environments, people have also put forward higher performance requirements for polyurethane low-temperature adhesives.

[0004] The Chinese patent application with publication number CN 111334241 A discloses a two-component polyurethane adhesive resistant to ultra-low temperatures and a preparation method thereof. The adhesive is divided into two parts: a main adhesive and a curing agent; the main raw material components of the main adhesive are: hydroxyl-terminated polyurethane prepolymer, polyether polyol B, filler, dehydrating agent, and adhesion promoter; the main raw material components of the curing agent are: isocyanate B, polyether polyol C, and filler; the main raw material components of the hydroxyl-terminated polyurethane prepolymer are: isocyanate A, polyether polyol A, and castor oil. The two-component polyurethane adhesive has high low temperature resistance and bonding strength.

[0005] The Chinese patent application with publication number CN 109354666 A discloses a low-temperature resistant thermoplastic polyurethane elastomer and a preparation method thereof, wherein the raw materials for preparing the low-temperature resistant thermoplastic polyurethane elastomer include the following components: 10-20 parts by weight of polyether polyol, 60-80 parts by weight of isophorone diisocyanate, 10-20 parts by weight of trifluoroethanol, 3-10 parts by weight of hexafluorobutanol, 20-30 parts by weight of linear low-density polyethylene, 5-10 parts by weight of styrene-isoprene copolymer, 1-3 parts by weight of vulcanizing agent, 0.3-1 parts by weight of vulcanization accelerator, 1-5 parts by weight of chain extender, and 1-4 parts by weight of catalyst. The low-temperature resistant thermoplastic polyurethane elastomer has the advantages of good low-temperature resistance, good wear resistance, good toughness, good elasticity, etc.

[0006] However, the above two-component polyurethane adhesive has a relatively complex composition and there is still room for improvement in performance. Summary of the invention

[0007] In view of the deficiencies in the prior art, the present application provides a method for preparing a low-temperature composite adhesive for a high-elastic composite tape. The low-temperature composite adhesive has a unique structure, excellent elasticity and low-temperature resistance, and high viscosity, and has broad application value.

[0008] In order to achieve the above objectives, this application adopts the following technical solutions: First, add polycaprolactone diol into a reaction kettle containing a solvent, heat to 90-100°C, and reflux and stir for 1-2 hours under nitrogen protection; Then, diisocyanate is added into the reactor, the reaction temperature is controlled at 70-90°C, and the reaction is carried out for 1-2 hours to generate a prepolymer; Then, a chain extender and a catalyst are added to the reactor, and the reaction is continued at 70-90°C for 2-4 hours to obtain a pre-product; Then, a plasticizer and an antioxidant are added to the reaction kettle, and stirring is continued at 70-90° C. for 3-5 hours under nitrogen protection, and the material is cooled and discharged to obtain the low-temperature composite adhesive; The structure of the polycaprolactone diol comprises: ; The structure of R includes and Any one of the following; m is an integer in the range of 1 to 3; n is an integer in the range of 1 to 3; and the relative molecular mass of the polycaprolactone diol does not exceed 800; The structure of the diisocyanate comprises: ; The structure of R' includes and Any of the following: The chain extender includes a triol; the triol includes any one of glycerol, trimethylolethane and trimethylolpropane.

[0009] Beneficial technical effects: The polycaprolactone diol used in the present application has a lower molecular weight, so the molecular chain is shorter, has higher mobility and lower steric hindrance, and therefore has higher reactivity and is more likely to react with diisocyanate.

[0010] Moreover, in the present application, no matter whether it is polycaprolactone diol molecule, diisocyanate molecule or triol molecule as chain extender, their structures do not contain aromatic groups, and the molecular chains of the composite adhesive finally obtained by the reaction are basically aliphatic carbon chains and alicyclic structures. The covalent bonds in these structures can rotate or bend, so that the molecular chains of the composite adhesive have strong flexibility and mobility, and the energy required for the movement of the molecular chains is low, so its Tg is low, so it can still maintain good performance at lower temperatures.

[0011] In addition, the molecular chains of the prepared low-temperature composite adhesive have strong flexibility and mobility, which can better cause physical self-crosslinking between molecular chains; and when subjected to external force, the molecular chain structure of the low-temperature composite adhesive will undergo changes such as bending and folding, further enhancing the physical crosslinking between the molecular chains of the low-temperature composite adhesive, thereby improving the elasticity and viscosity of the low-temperature composite adhesive. At the same time, there are a large number of nitrogen and oxygen atoms between the molecular chains after cross-linking, which can produce a large number of hydrogen bonds, enhance the intermolecular force, and achieve the effect of further improving the physical crosslinking, so that the elasticity and viscosity of the low-temperature composite adhesive are further enhanced. Finally, a low-temperature composite adhesive that can be used for high-elasticity tapes is formed. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the chemical reaction process for preparing low-temperature composite adhesive for high-elastic composite tape.

[0013] Figure 2 is the chemical structural formula of the pre-product of the low-temperature composite adhesive prepared in Example 1.

[0014] Figure 3 The present invention is a flow chart of preparing low temperature composite adhesive for high elastic composite tape.

[0015] Figure 4 It is a schematic diagram of the stress changes on the molecular chains of the prepared low-temperature composite adhesive. DETAILED DESCRIPTION

[0016] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer, the present application is further described in detail below in conjunction with the embodiments. However, this should not be understood as the scope of the present application being limited to the following examples. Without departing from the above-mentioned method ideas of the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0017] In this application, the terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit the application.

[0018] As used in this application and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0019] This application adopts the following technical solutions: First, add polycaprolactone diol into a reaction kettle containing a solvent, heat to 90-100°C, and reflux and stir for 1-2 hours under nitrogen protection; Then, diisocyanate is added into the reactor, the reaction temperature is controlled at 70-90°C, and the reaction is carried out for 1-2 hours to generate a prepolymer; Then, a chain extender and a catalyst are added to the reactor, and the reaction is continued at 70-90°C for 2-4 hours to obtain a pre-product; Then, a plasticizer and an antioxidant are added to the reaction kettle, and stirring is continued at 70-90° C. for 3-5 hours under nitrogen protection, and the material is cooled and discharged to obtain the low-temperature composite adhesive; The structure of the polycaprolactone diol comprises: ; The structure of R includes and Any one of the following; m is an integer in the range of 1 to 3; n is an integer in the range of 1 to 3; and the relative molecular mass of the polycaprolactone diol does not exceed 800; The structure of the diisocyanate comprises: ; The structure of R' includes and Any of the following: The chain extender includes a triol; the triol includes any one of glycerol, trimethylolethane and trimethylolpropane.

[0020] The polycaprolactone diol has a lower molecular weight, so the molecular chain is shorter, has higher mobility and lower steric hindrance, and therefore has higher reactivity and is more likely to react with diisocyanate.

[0021] Schematic diagram of the chemical reaction process for preparing low-temperature composite adhesive for high elastic composite tape Figure 1 shown.

[0022] The molecular chains of the prepared low-temperature composite adhesive have strong flexibility and mobility, so the physical self-crosslinking between the molecular chains can be better; and when subjected to external force, the molecular chain structure of the low-temperature composite adhesive will bend, fold, and other changes, further enhancing the physical crosslinking between the molecular chains of the low-temperature composite adhesive, thereby improving the elasticity and viscosity of the low-temperature composite adhesive. The schematic diagram of the change of the molecular chain of the low-temperature composite adhesive under force is shown in Figure 4 shown.

[0023] In a possible implementation, the solvent includes one or more of ethyl acetate, dichloromethane, toluene and DMF.

[0024] In a possible implementation, the structure of the prepolymer includes: ; The structure of R includes and Any one of; the structure of R' includes ,and Any one of; m is an integer in the range of 1 to 3; n is an integer in the range of 1 to 3.

[0025] In a possible implementation, the catalyst includes any one of an amine catalyst and an organic metal catalyst.

[0026] In a possible implementation, the amine catalyst includes any one of triethylamine, N,N-dimethylbenzylamine and N,N-dimethylcyclohexylamine.

[0027] In a possible implementation, the organometallic catalyst includes any one of bismuth neodecanoate, bismuth isooctanoate and dibutyltin dilaurate.

[0028] In a possible implementation, the structure of the pre-product includes: ; The structure of R includes and Any one of; the structure of R' includes and Any one of; R'' structure includes ,and Any one of; m is an integer in the range of 1 to 3; n is an integer in the range of 1 to 3.

[0029] In a possible implementation, the plasticizer includes any one of dibutyl phthalate, dioctyl phthalate and dioctyl terephthalate.

[0030] In a possible implementation, the antioxidant includes any one of the antioxidant 1010 , the antioxidant 1076 , and the antioxidant 168 .

[0031] In a possible implementation, the mass ratio of the polycaprolactone diol, solvent, diisocyanate, chain extender, catalyst, plasticizer and antioxidant is: (30-50): (20-30): (20-30): (1-2): (0.1-0.2): (5-15): (0.1-0.5).

[0032] The experimental raw materials used in this application come from the following sources: Polycaprolactone diol: Hunan Juren New Materials Co., Ltd.; Solvent: Jiangsu Bosite Chemical Technology Co., Ltd.; Diisocyanate: Jiangsu Bosite Chemical Technology Co., Ltd.; Chain extender: Qianyan Chemical Technology (Wuhan) Co., Ltd. Catalyst: Qianyan Chemical Technology (Wuhan) Co., Ltd.; Plasticizer: Qianyan Chemical Technology (Wuhan) Co., Ltd. Antioxidant: Qianyan Chemical Technology (Wuhan) Co., Ltd.

[0033] The following will specifically describe a method for preparing a low-temperature composite adhesive for a high-elastic composite tape provided by the present application in combination with different embodiments.

[0034] Embodiment 1:

[0035] like Figure 3 As shown, a method for preparing a low-temperature composite adhesive for a high-elastic composite adhesive tape comprises the following steps: 1. Add polycaprolactone diol into a reaction kettle containing ethyl acetate, heat to 95°C, and reflux and stir for 1.5 hours under nitrogen protection; The structure of the polycaprolactone diol is: ; 2. Then add the structure into the reactor The reaction temperature is controlled at 80°C for 1.5 hours to generate a prepolymer; 3. Then add glycerol and triethylamine into the reaction kettle and continue to react at 80°C for 3 hours to obtain the pre-product; 4. Then, dibutyl phthalate and antioxidant 1010 were added into the reaction kettle, and stirring was continued at 80° C. for 4 hours under nitrogen protection, and the material was cooled and discharged to obtain the low-temperature composite adhesive.

[0036] The chemical structure of the low temperature composite adhesive pre-product is as follows: Figure 2 shown.

[0037] In the above steps 1 to 4, the mass ratio of the polycaprolactone diol, ethyl acetate, diisocyanate, glycerol, triethylamine, dibutyl phthalate and antioxidant 1010 is 40:25:25:1.8:0.1:8:0.1.

[0038] Embodiment 2: like Figure 3 As shown, a method for preparing a low-temperature composite adhesive for a high-elastic composite adhesive tape comprises the following steps: 1. Add polycaprolactone diol into a reaction kettle containing toluene, heat to 90°C, and reflux and stir for 2 hours under nitrogen protection; The structure of the polycaprolactone diol is: ; 2. Then add the structure into the reactor The diisocyanate was added, the reaction temperature was controlled at 75°C, and the reaction was carried out for 2 hours to generate a prepolymer; 3. Then, trimethylolethane and N,N-dimethylbenzylamine were added to the reaction kettle, and the reaction was continued at 75° C. for 2.5 hours to obtain a pre-product; 4. Then, dioctyl terephthalate and antioxidant 1076 were added into the reaction kettle, and stirring was continued at 80° C. for 4 hours under nitrogen protection, and the material was cooled and discharged to obtain the low-temperature composite adhesive.

[0039] In the above steps 1 to 4, the mass ratio of the polycaprolactone diol, toluene, diisocyanate, trimethylolethane, N,N-dimethylbenzylamine, dioctyl terephthalate and antioxidant 1076 is 35:30:20:1.5:0.2:13:0.3.

[0040] Embodiment 3: like Figure 3 As shown, a method for preparing a low-temperature composite adhesive for a high-elastic composite adhesive tape comprises the following steps: 1. Add polycaprolactone diol into a reactor containing dichloromethane, heat to 100°C, and reflux and stir for 1 hour under nitrogen protection; The structure of the polycaprolactone diol is: ; 2. Then add the structure into the reactor The diisocyanate was added, the reaction temperature was controlled at 90°C, and the reaction was carried out for 1 hour to generate a prepolymer; 3. Then, trimethylolpropane and bismuth neodecanoate were added to the reaction kettle, and the reaction was continued at 90° C. for 4 hours to obtain a pre-product; 4. Then, dioctyl phthalate and antioxidant 168 were added to the reaction kettle, and stirring was continued at 90° C. for 5 hours under nitrogen protection, and the material was cooled and discharged to obtain the low-temperature composite adhesive.

[0041] In the above steps 1 to 4, the mass ratio of the polycaprolactone diol, dichloromethane, diisocyanate, trimethylolpropane, bismuth neodecanoate, dioctyl phthalate and antioxidant 168 is 40:25:20:2:0.1:12.5:0.4.

[0042] Embodiment 4: like Figure 3 As shown, a method for preparing a low-temperature composite adhesive for a high-elastic composite adhesive tape comprises the following steps: 1. Add polycaprolactone diol into a reaction kettle containing DMF, heat to 95°C, and reflux and stir for 2 hours under nitrogen protection; The structure of the polycaprolactone diol is: ; 2. Then add the structure into the reactor The diisocyanate was added, the reaction temperature was controlled at 85°C, and the reaction was carried out for 1.5 hours to generate a prepolymer; 3. Then, glycerol and N,N-dimethylcyclohexylamine were added to the reaction kettle, and the reaction was continued at 85° C. for 3.5 hours to obtain a pre-product; 4. Then, dibutyl phthalate and antioxidant 1010 were added to the reaction kettle, and stirring was continued at 90° C. for 5 hours under nitrogen protection, and the material was cooled and discharged to obtain the low-temperature composite adhesive.

[0043] In the above steps 1 to 4, the mass ratio of the polycaprolactone diol, DMF, diisocyanate, glycerol, N,N-dimethylcyclohexylamine, dibutyl phthalate and antioxidant 1010 is 30:30:28:1.5:0.2:10:0.3.

[0044] Embodiment 5:

[0045] like Figure 3 As shown, a method for preparing a low-temperature composite adhesive for a high-elastic composite adhesive tape comprises the following steps: 1. Add polycaprolactone diol into a reaction kettle containing ethyl acetate, heat to 90°C, and reflux and stir for 1 hour under nitrogen protection; The structure of the polycaprolactone diol is: ; 2. Then add the structure into the reactor The diisocyanate was added, the reaction temperature was controlled at 80°C, and the reaction was carried out for 1 hour to generate a prepolymer; 3. Then, trimethylolpropane and bismuth isooctanoate were added to the reactor, and the reaction was continued at 80° C. for 3 hours to obtain a pre-product; 4. Then, dioctyl terephthalate and antioxidant 1076 were added into the reaction kettle, and stirring was continued at 80° C. for 3 hours under nitrogen protection, and the material was cooled and discharged to obtain the low-temperature composite adhesive.

[0046] In the above steps 1 to 4, the mass ratio of the polycaprolactone diol, ethyl acetate, diisocyanate, trimethylolpropane, bismuth isooctanoate, dioctyl terephthalate and antioxidant 1076 is: 45:22:23:1:0.1:8.5:0.4.

[0047] Embodiment 6: like Figure 3 As shown, a method for preparing a low-temperature composite adhesive for a high-elastic composite adhesive tape comprises the following steps: 1. Add polycaprolactone diol into a reaction kettle containing toluene, heat to 100°C, and reflux and stir for 1.5 hours under nitrogen protection; The structure of the polycaprolactone diol is: ; 2. Then add the structure into the reactor The reaction temperature is controlled at 90°C for 1.5 hours to generate a prepolymer; 3. Then, trimethylolethane and dibutyltin dilaurate were added to the reaction kettle, and the reaction was continued at 90° C. for 4 hours to obtain a pre-product; 4. Then, dibutyl phthalate and antioxidant 168 were added to the reaction kettle, and stirring was continued at 90° C. for 4 hours under nitrogen protection, and the material was cooled and discharged to obtain the low-temperature composite adhesive.

[0048] In the above steps 1 to 4, the mass ratio of the polycaprolactone diol, toluene, diisocyanate, trimethylolethane, dibutyltin dilaurate, dibutyl phthalate and antioxidant 168 is 35:28:25:1.5:0.2:10:0.3.

[0049] Comparative Example 1: A method for preparing a low-temperature composite adhesive for a high-elastic composite adhesive tape comprises the following steps: 1. Add polycaprolactone diol into a reaction kettle containing ethyl acetate, heat to 95°C, and reflux and stir for 1.5 hours under nitrogen protection; The structure of the polycaprolactone diol is: ; 2. Then add the structure into the reactor The reaction temperature is controlled at 80°C for 1.5 hours to generate a prepolymer; 3. Then add glycerol and triethylamine into the reaction kettle and continue to react at 80°C for 3 hours to obtain the pre-product; 4. Then, dibutyl phthalate and antioxidant 1010 were added into the reaction kettle, and stirring was continued at 80° C. for 4 hours under nitrogen protection, and the material was cooled and discharged to obtain the low-temperature composite adhesive.

[0050] In the above steps 1 to 4, the mass ratio of the polycaprolactone diol, ethyl acetate, diisocyanate, glycerol, triethylamine, dibutyl phthalate and antioxidant 1010 is 40:25:25:1.8:0.1:8:0.1.

[0051] Comparative Example 2: A method for preparing a low-temperature composite adhesive for a high-elastic composite adhesive tape comprises the following steps: 1. Add polycaprolactone diol into a reactor containing dichloromethane, heat to 100°C, and reflux and stir for 1 hour under nitrogen protection; The structure of the polycaprolactone diol is: ; 2. Then add the structure into the reactor The reaction temperature is controlled at 90°C for 1 hour to generate a prepolymer; 3. Then, ethylene glycol and bismuth neodecanoate were added to the reaction kettle, and the reaction was continued at 90° C. for 4 hours to obtain a pre-product; 4. Then, dioctyl phthalate and antioxidant 168 were added to the reaction kettle, and stirring was continued at 90° C. for 5 hours under nitrogen protection, and the material was cooled and discharged to obtain the low-temperature composite adhesive.

[0052] In the above steps 1 to 4, the mass ratio of the polycaprolactone diol, dichloromethane, diisocyanate, ethylene glycol, bismuth neodecanoate, dioctyl phthalate and antioxidant 168 is: 40:25:20:2:0.1:12.5:0.4.

[0053] Comparative Example 3: A method for preparing a low-temperature composite adhesive for a high-elastic composite adhesive tape comprises the following steps: 1. Add polycaprolactone diol into a reaction kettle containing toluene, heat to 100°C, and reflux and stir for 1.5 hours under nitrogen protection; The structure of the polycaprolactone diol is: ; 2. Then add the structure into the reactor The reaction temperature is controlled at 90°C for 1.5 hours to generate a prepolymer; 3. Then, 1,4-butanediol and dibutyltin dilaurate were added to the reaction kettle, and the reaction was continued at 90° C. for 4 hours to obtain a pre-product; 4. Then, dibutyl phthalate and antioxidant 168 were added to the reaction kettle, and stirring was continued at 90° C. for 4 hours under nitrogen protection, and the material was cooled and discharged to obtain the low-temperature composite adhesive.

[0054] In the above steps 1 to 4, the mass ratio of the polycaprolactone diol, toluene, diisocyanate, 1,4-butanediol, dibutyltin dilaurate, dibutyl phthalate and antioxidant 168 is 35:28:25:1.5:0.2:10:0.3.

[0055] With reference to GB / T 29611-2013, differential scanning calorimetry (DSC) was used to test the glass transition temperature of the low-temperature composite adhesive used for high elastic composite tape.

[0056] With reference to GB / T 2794-2022, the rotational rheometer method was used to test the viscosity of the low-temperature composite adhesive used for high-elastic composite tape under low-temperature conditions.

[0057] Referring to HG / T 4222-2011, the hot melt adhesive low temperature flexibility test method is used to test the ability of the low temperature composite adhesive used for high elastic composite tape to maintain flexibility and elasticity under low temperature conditions.

[0058] Table 1 Performance test results of low temperature composite adhesives prepared in Examples 1-6 and Comparative Examples 1-3

[0059] As can be seen from Table 1, the glass transition temperature Tg, low temperature viscosity and low temperature flexibility of Examples 1-6 are better than those of Comparative Examples 1-3. This is because the molecular chains of the low temperature composite adhesive for high elastic composite tape prepared in the present application are basically aliphatic carbon chains and alicyclic structures, in which the covalent bonds can rotate or bend, so that the molecular chains of the low temperature composite adhesive have strong flexibility and mobility, and the energy required for the movement of the molecular chain is lower, so its Tg is lower, so it can still maintain good performance at lower temperatures.

[0060] In addition, the molecular chains of the prepared low-temperature composite adhesive have strong flexibility and mobility, which can better cause physical self-crosslinking between molecular chains; and when subjected to external force, the molecular chain structure of the low-temperature composite adhesive will bend, fold, and other changes, further enhancing the physical crosslinking between the molecular chains of the low-temperature composite adhesive, thereby improving the elasticity and viscosity of the low-temperature composite adhesive. At the same time, there are a large number of nitrogen and oxygen atoms between the molecular chains after crosslinking, which can produce a large number of hydrogen bonds, enhance the intermolecular force, and achieve the effect of further improving the physical crosslinking, so that the elasticity and viscosity of the low-temperature composite adhesive are further enhanced.

[0061] In contrast, aromatic groups are introduced into the molecular chain structure of the composite adhesive prepared in Comparative Example 1, which reduces the flexibility and mobility of the molecular chain, so that the Tg is higher and the low temperature resistance is poor; and although the viscosity is higher, the elasticity is reduced; The chain extender used in the composite adhesive prepared in Comparative Example 2 is diol, and the cross-linking effect of the molecular chain structure finally formed is weaker than that using triol, so the elasticity and viscosity are lower.

[0062] The molecular chain structure of the composite adhesive prepared in Comparative Example 3 introduces aromatic groups and uses diols. Therefore, although the viscosity is also high, the low temperature resistance and elasticity are the worst.

[0063] The above results show and describe the basic principles and main features of the present application as well as the advantages of the present application.

[0064] Those skilled in the art should understand that the present application is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present application. Without departing from the spirit and scope of the present application, the present application may have various changes and improvements, and these changes and improvements fall within the scope of the present application for which protection is sought. The scope of protection sought in the present application is defined by the equivalents of the attached claims.

Claims

1. A method for preparing a low-temperature composite adhesive for a high-elastic composite adhesive tape, characterized in that: The steps include: First, add polycaprolactone diol into a reaction kettle containing a solvent, heat to 90-100°C, and reflux and stir for 1-2 hours under nitrogen protection; Then, diisocyanate is added into the reactor, the reaction temperature is controlled at 70-90°C, and the reaction is carried out for 1-2 hours to generate a prepolymer; Then, a chain extender and a catalyst are added to the reactor, and the reaction is continued at 70-90° C. for 2-4 hours to obtain a pre-product; Then, a plasticizer and an antioxidant are added to the reaction kettle, and stirring is continued at 70-90° C. for 3-5 hours under nitrogen protection, and the material is cooled and discharged to obtain the low-temperature composite adhesive; The structure of the polycaprolactone diol comprises: ； The structure of R includes and Any one of the following; m is an integer in the range of 1 to 3; n is an integer in the range of 1 to 3; and the relative molecular mass of the polycaprolactone diol does not exceed 800; The structure of the diisocyanate comprises: ； The structure of R' includes and Any of the following; The chain extender includes a triol; the triol includes any one of glycerol, trimethylolethane and trimethylolpropane.

2. The method for preparing a low-temperature composite adhesive for a high-elastic composite adhesive tape according to claim 1, characterized in that: The solvent includes one or more of ethyl acetate, dichloromethane, toluene and DMF.

3. The method for preparing a low-temperature composite adhesive for a high-elastic composite adhesive tape according to claim 1, characterized in that: The structure of the prepolymer comprises: ； The structure of R includes and Any one of; the structure of R' includes and Any one of; m is an integer in the range of 1 to 3; n is an integer in the range of 1 to 3.

4. The method for preparing a low-temperature composite adhesive for a high-elastic composite adhesive tape according to claim 1, characterized in that: The catalyst includes any one of an amine catalyst and an organic metal catalyst; the amine catalyst includes any one of triethylamine, N,N-dimethylbenzylamine and N,N-dimethylcyclohexylamine; the organic metal catalyst includes any one of bismuth neodecanoate, bismuth isooctanoate and dibutyltin dilaurate.

5. The method for preparing a low-temperature composite adhesive for a high-elastic composite adhesive tape according to claim 1, characterized in that: The structure of the pre-product comprises: ； The structure of R includes and Any one of; the structure of R' includes and Any one of; R'' structure includes ,and Any one of; m is an integer in the range of 1 to 3; n is an integer in the range of 1 to 3.

6. The method for preparing a low-temperature composite adhesive for a high-elastic composite adhesive tape according to claim 1, characterized in that: The plasticizer includes any one of dibutyl phthalate, dioctyl phthalate and dioctyl terephthalate; the antioxidant includes any one of antioxidant 1010, antioxidant 1076 and antioxidant 168.

7. The method for preparing a low-temperature composite adhesive for a high-elastic composite adhesive tape according to claim 1, characterized in that: The mass ratio of the polycaprolactone diol, solvent, diisocyanate, chain extender, catalyst, plasticizer and antioxidant is: (30-50): (20-30): (20-30): (1-2): (0.1-0.2): (5-15): (0.1-0.5).

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