Low-temperature adhesive for double-layer composite adhesive sticker and preparation method of low-temperature adhesive

Abstract

The invention relates to the technical field of low-temperature adhesives, and discloses a low-temperature adhesive for a double-layer composite adhesive sticker and a preparation method of the low-temperature adhesive. The low-temperature glue is prepared by the following steps: copolymerizing allyl methyl succinate, ethylene glycol dimethacrylate and bisphenol A (4-ethoxy-3, 5-divinyl phenyl) diglycidyl ether, and adding modified menthol and modified dodecafluoroheptanoic acid. The low-temperature adhesive has good hydrophobicity, low-temperature adhesive property, mechanical property and low glass transition temperature, the preparation process of the low-temperature adhesive is simple, the low-temperature adhesive is green and environment-friendly, the size and the shape of the low-temperature adhesive can be randomly cut, and the low-temperature adhesive is wide in application.

Description

Technical Field

[0001] The invention belongs to the technical field of low-temperature adhesives, and in particular relates to a low-temperature adhesive for a double-layer composite adhesive tape and a preparation method thereof. Background Art

[0002] Due to the needs of special environments, low-temperature adhesives are favored for their unique low-temperature curing performance. Low-temperature adhesives that can be used to prepare double-layer composite adhesives can maintain a certain degree of flexibility while rapidly curing at low temperatures. In low-temperature environments, they can achieve high bonding strength in a relatively short curing time, and withstand distortion, stretching and impact, reduce material damage caused by low temperatures, maintain strong bonding performance, and tolerate extreme temperatures. They are not easy to fall off. However, due to the significant differences in the expansion and contraction coefficients of the adhesive layer and the base material, the traditional low-temperature composite adhesive will expand unevenly due to temperature changes under long-term extreme temperatures. There will be peeling and delamination, the adhesive layer will become brittle, and the impact resistance and tensile strength will decrease, leading to its failure. Therefore, double-layer composite low-temperature adhesives are widely used in the cold storage and transportation industries, transportation infrastructure maintenance and repair, and the bonding and sealing of aircraft structures, automotive parts, electronic components, circuit boards, etc.

[0003] A Chinese patent application with publication number CN 116656265 A discloses a low-temperature adhesive tape, in which a C5 resin with a low glass transition temperature and a liquid terpene resin are added to prepare an adhesive layer, and the prepared tape can maintain good peeling force at -10~-40°C. However, liquid terpene resin is easily affected by factors such as ultraviolet rays, oxygen, and temperature changes, and the adhesive may become hard, brittle, and have reduced viscosity, thereby affecting its long-term performance and bonding effect, reducing the reliability and service life of the bonded structure, and the resin is not water-resistant and is prone to aging and failure in a humid environment.

[0004] Therefore, it is particularly important to provide a low-temperature adhesive with simple preparation process, good adhesive properties and waterproofness. Summary of the invention

[0005] The present invention aims to provide a low-temperature adhesive for a double-layer composite adhesive tape and a preparation method thereof. The low-temperature adhesive can maintain good bonding performance and flexibility in a low-temperature environment, and has excellent hydrophobicity, and can also function in a humid environment.

[0006] To achieve the above object, the present invention provides a method for preparing a low-temperature adhesive for a double-layer composite adhesive tape, comprising: Step S1, adding allyl methyl succinate and ethylene glycol dimethacrylate into a solvent to dissolve, adding a photoinitiator, and reacting under UV light to obtain a polymer A; Step S2, adding bisphenol A (4-ethoxy-3,5-divinylphenyl) diglycidyl ether and polymer A into a good solvent to dissolve, adding a photoinitiator, and reacting under UV light to obtain polymer B; Step S3, adding menthol and a silane coupling agent into a solvent to dissolve, and reacting to obtain a silanized derivative of menthol; Step S4, adding menthol silylated derivative and polydimethylsiloxane into a solvent to dissolve, adding a catalyst, and reacting to obtain polymer C; Step S5, adding dodecafluoroheptanoic acid and a silane coupling agent into a solvent to dissolve, and reacting under nitrogen protection to obtain a silylated derivative of dodecafluoroheptanoic acid; Step S6, adding the silylated derivative of dodecafluoroheptanoic acid and copolymer C into a solvent to dissolve, adding a catalyst, and reacting to obtain polymer D; Step S7, adding polymer B and polymer D into a solvent to dissolve, adding a photoinitiator, reacting under UV light, adding a leveling agent, a dispersant, a plasticizer and an ultraviolet absorber after the reaction, stirring at room temperature to obtain a low-temperature glue.

[0007] Preferably, in step S1, the mass ratio of allyl methyl succinate, ethylene glycol dimethacrylate, photoinitiator and solvent is 1: (0.6-0.7): (0.008-0.017): (4-5).

[0008] Preferably, in step S1, the reaction temperature is 60-80° C., and the reaction time is 6-8 h.

[0009] Preferably, in step S2, the good solvent is any one or more of dimethyl sulfoxide, cyclohexane, toluene, N, N'-dimethylformamide, ionic liquid and low eutectic solvent.

[0010] Preferably, in step S2, the mass ratio of bisphenol A (4-ethoxy-3,5-divinylphenyl) diglycidyl ether, polymer A, photoinitiator and solvent is 1: (1-4): (0.01-0.05): (5-6).

[0011] Preferably, in step S2, the reaction temperature is 70-90° C., and the reaction time is 20-24 h.

[0012] Preferably, in step S3, the mass ratio of menthol, silane coupling agent and solvent is 1:(0.5-1):(4-5).

[0013] Preferably, in step S3, the reaction temperature is 100-120° C., and the reaction time is 4-6 h.

[0014] Preferably, in step S4, the mass ratio of the polydimethylsiloxane, the menthol siloxane derivative and the solvent is 1:(1-3):(4-5).

[0015] Preferably, in step S4, the reaction temperature is 60-100° C., and the reaction time is 10-12 h.

[0016] Preferably, in step S5, the mass ratio of the dodecafluoroheptanoic acid, the silane coupling agent and the solvent is 1:(0.5-1):(4-5).

[0017] Preferably, in step S5, the reaction temperature is 50-80° C., and the reaction time is 6-8 h.

[0018] Preferably, in step S6, the mass ratio of the silylated derivative of dodecafluoroheptanoic acid, polymer C, catalyst and solvent is 1: (0.5-2): (0.0075-0.075): (4-5).

[0019] Preferably, in step S6, the reaction temperature is 80-120° C., and the reaction time is 10-12 h.

[0020] Preferably, in step S7, the leveling agent is any one or more of silicone oil and styrene maleic anhydride copolymer.

[0021] Preferably, in step S7, the dispersant is polyethylene glycol; and the plasticizer is any one or more of dioctyl phthalate and nonylphenoxyacetone.

[0022] Preferably, in step S7, the ultraviolet absorber is any one or more of benzophenone, UV-P, and UV-326; and the stirring time is 24 to 36 h.

[0023] Preferably, in step S7, the mass ratio of the polymer B, polymer D, photoinitiator, solvent, dispersant, leveling agent, plasticizer and ultraviolet absorber is 1: (0.2-0.5): (0.01-0.05): (4-5): (0.05-0.1): (0.002-0.006): (0.26-0.52): (0.001-0.004).

[0024] Preferably, in step S7, the reaction temperature is 60-80° C., and the reaction time is 10-16 h.

[0025] Preferably, the solvent is any one or more of methanol, toluene, xylene, acetone, acetonitrile, ethanol, dichloromethane, and tetrahydrofuran.

[0026] Preferably, the silane coupling agent is any one or more of 3-aminopropyltriethoxysilane, methacryloxypropyltrimethoxysilane, and vinyltriethoxysilane.

[0027] Preferably, the catalyst is any one or more of a platinum catalyst, a palladium catalyst, a vanadium catalyst, an iron catalyst, and a nickel catalyst.

[0028] Preferably, the photoinitiator is any one or more of photoinitiator-1173, photoinitiator-184, TPO, TPO-L, IHT-PI 910, and initiator-907.

[0029] The present invention also provides a double-layer composite low-temperature adhesive, which is obtained by adopting the above-mentioned preparation method.

[0030] Preferably, the release paper is silicone oil paper.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The present invention adopts a copolymer of allyl methyl succinate and ethylene glycol dimethacrylate as a basic unit, and copolymerizes it with bisphenol A (4-ethoxy-3,5-divinylphenyl) diglycidyl ether to give the low-temperature adhesive rapid polymerization at low temperature, low glass transition temperature and low shrinkage. Allyl methyl succinate and ethylene glycol dimethacrylate copolymerize to form a long-chain high molecular polymer, which can maintain the flexibility of the polymer and increase the molecular weight of the overall polymer; the active glycidyl ether group in the structure of bisphenol A (4-ethoxy-3,5-divinylphenyl) diglycidyl ether can react with a variety of groups, and can modify the long chain of the copolymer of allyl methyl succinate and ethylene glycol dimethacrylate, improve its fluidity and processability, and reduce its glass transition temperature. The repeating units of ethylene oxide, phenol and ether in the structure give it unique thermodynamic stability and dimensional stability, so that it avoids causing stress deformation of the substrate during the curing process.

[0032] (2) The present invention adds silicon-modified menthol and silicon-modified dodecafluoroheptanoic acid to the copolymer of allyl methyl succinate, ethylene glycol dimethacrylate and bisphenol A diglycidyl ether to obtain a super-hydrophobic polymer, introduces silicon-containing segments into the polymer, and improves the antistatic, antifouling and mechanical properties of the low-temperature adhesive; the menthol structure contains a hydrophobic long carbon chain and a hydrophilic hydroxyl group, and dodecafluoroheptanoic acid has a highly hydrophobic carbon chain. Menthol and dodecafluoroheptanoic acid are copolymerized, and the hydrophobic carbon chain of menthol can be embedded in the hydrophobic layer of dodecafluoroheptanoic acid to form a tight hydrophobic layer, reduce interfacial tension, give the adhesive sticker hydrophobic and oil-proof properties, extend the service life of the coating and the adhesive sticker, and expand the scope of application. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1The present invention is a flow chart for preparing low-temperature adhesive for double-layer composite adhesive tape.

[0034] Figure 2 It is a schematic diagram of the structure of a double-layer composite low-temperature adhesive tape.

[0035] The meaning of the reference numerals: 1, upper release paper, 2, low temperature glue, 3, lower release paper. DETAILED DESCRIPTION

[0036] The following embodiments are only used to more clearly illustrate the technical solutions of the present invention, and are not intended to limit the protection scope of the present invention.

[0037] The main compounds used in the examples and comparative examples are all commercially available products without any further purification.

[0038] Example 1

[0039] like Figure 1 As shown, a method for preparing a low-temperature adhesive for a double-layer composite adhesive tape comprises the following steps: Step S1, weigh 10 g of allyl methyl succinate and 6 g of ethylene glycol dimethacrylate, add 50 mL of methanol, sonicate to completely dissolve them, add 0.08 g of photoinitiator-1173, copolymerize under continuous UV light at 60°C for 8 h, and obtain copolymer A.

[0040] Step S2: Weigh 10 g of bisphenol A (4-ethoxy-3,5-divinylphenyl) diglycidyl ether and 10 g of copolymer A, mix and dissolve in 63 mL of cyclohexane, add 0.1 g of photoinitiator-1173, and copolymerize under continuous UV illumination at 70° C. for 24 h to obtain copolymer B.

[0041] Step S3, weigh 10 g of menthol and 5 g of 3-aminopropyltriethoxysilane, mix them, dissolve them in 45 mL of tetrahydrofuran, evacuate the system, and react at 100° C. for 6 h under anhydrous conditions to obtain a menthol silylated derivative.

[0042] Step S4: weigh 10 g of polydimethylsiloxane and 10 g of menthol silylated derivative, dissolve them in 45 mL of tetrahydrofuran, add 0.01 g of platinum catalyst, and polymerize at 60° C. for 12 h to obtain copolymer C.

[0043] Step S5, under nitrogen protection, weigh 10 g of dodecafluoroheptanoic acid and 5 g of 3-aminopropyltriethoxysilane, mix them, dissolve them in 45 mL of tetrahydrofuran, evacuate the system, and react at 50° C. for 8 h under anhydrous conditions to obtain a silylated derivative of dodecafluoroheptanoic acid.

[0044] Step S6, weigh 10 g of the silylated derivative of dodecafluoroheptanoic acid and 5 g of copolymer C, dissolve them in 45 mL of tetrahydrofuran, add 0.075 g of platinum catalyst, and react at 80° C. for 12 h to obtain copolymer D.

[0045] Step S7, weigh 10 g of copolymer B and 1 g of copolymer D, dissolve them in 45 g of tetrahydrofuran, add 0.5 g of photoinitiator -1173, react under UV light at 60°C for 16 h; add 2 g of silicone oil, polyethylene glycol, 2.6 g of dioctyl phthalate and 0.1 g of UV-326, stir at room temperature for 24 h to obtain a low-temperature glue.

[0046] Example 2

[0047] like Figure 1 As shown, a method for preparing a low-temperature adhesive for a double-layer composite adhesive tape comprises the following steps: Step S1, weigh 10 g of allyl methyl succinate and 6.5 g of ethylene glycol dimethacrylate, add 57 mL of methanol, sonicate to completely dissolve them, add 0.1 g of photoinitiator -1173, copolymerize under continuous UV light at 70°C for 7 h to obtain polymer A.

[0048] Step S2: Weigh 10 g of bisphenol A (4-ethoxy-3,5-divinylphenyl) diglycidyl ether and 25 g of copolymer A, mix them, dissolve them in 50 mL of cyclohexane, add 0.3 g of photoinitiator-1173, and copolymerize them under continuous UV illumination at 80° C. for 22 h to obtain polymer B.

[0049] Step S3, accurately weigh 10 g of menthol and 7.5 g of 3-aminopropyltriethoxysilane, mix and dissolve in 50 mL of tetrahydrofuran, evacuate the system, and react at 110° C. for 5 h under anhydrous conditions to obtain a menthol silylated derivative.

[0050] Step S4: weigh 10 g of polydimethylsiloxane and 20 g of menthol silylated derivative, dissolve them in 50 mL of tetrahydrofuran, add 0.1 g of platinum catalyst, and polymerize at 80° C. for 11 h to obtain polymer C.

[0051] Step S5, under nitrogen protection, weigh 10 g of dodecafluoroheptanoic acid and 7.5 g of 3-aminopropyltriethoxysilane, mix them, dissolve them in 50 mL of tetrahydrofuran, evacuate the system, and react at 65° C. for 7 h under anhydrous conditions to obtain a silylated derivative of dodecafluoroheptanoic acid.

[0052] Step S6, weigh 10 g of the silylated derivative of dodecafluoroheptanoic acid and 10 g of polymer C, mix them, dissolve them in 50 mL of tetrahydrofuran, add 0.1 g of platinum catalyst, react at 100° C. for 11 h, and obtain polymer D.

[0053] Step S7, weigh 10 g of copolymer B and 3 g of copolymer D, dissolve them in 45 g of tetrahydrofuran, add 1 g of photoinitiator-1173, react under UV light at 70°C for 12 h; add 3 g of silicone oil, polyethylene glycol, 4.2 g of dioctyl phthalate and 0.2 g of UV-326, stir at room temperature for 30 h to obtain a low-temperature glue.

[0054] Example 3

[0055] like Figure 1 As shown, a method for preparing a low-temperature adhesive for a double-layer composite adhesive tape comprises the following steps: Step S1, weigh 10 g of allyl methyl succinate and 7 g of ethylene glycol dimethacrylate, add 63 mL of methanol, sonicate to completely dissolve them, add 0.17 g of photoinitiator -1173, copolymerize under continuous UV light at 80°C for 6 h to obtain polymer A.

[0056] Step S2: Weigh 10 g of bisphenol A (4-ethoxy-3,5-divinylphenyl) diglycidyl ether and 40 g of copolymer A, mix them, dissolve them in 75 mL of cyclohexane, add 0.5 g of photoinitiator-1173, and polymerize them under continuous UV light at 90° C. for 20 h to obtain polymer B.

[0057] Step S3, weigh 10 g of menthol and 10 g of 3-aminopropyltriethoxysilane, mix them, dissolve them in 56 mL of tetrahydrofuran, evacuate the system, and react at 120° C. for 4 h under anhydrous conditions to obtain a silylated menthol derivative.

[0058] Step S4: weigh 10 g of polydimethylsiloxane and 30 g of menthol silylated derivative, dissolve them in 56 mL of tetrahydrofuran, add 0.4 g of platinum catalyst, and polymerize at 100° C. for 10 h to obtain polymer C.

[0059] Step S5, under nitrogen protection, weigh 10 g of dodecafluoroheptanoic acid and 10 g of 3-aminopropyltriethoxysilane, mix them, dissolve them in 56 mL of tetrahydrofuran, evacuate the system, and react at 80° C. for 6 h under anhydrous conditions to obtain a silylated derivative of dodecafluoroheptanoic acid.

[0060] Step S6, weigh 10 g of the silylated derivative of dodecafluoroheptanoic acid and 20 g of polymer C, mix them, dissolve them in 56 mL of tetrahydrofuran, add 0.75 g of platinum catalyst, react at 120° C. for 10 h, and obtain polymer D.

[0061] Step S7, weigh 10 g of copolymer B and 5 g of copolymer D, dissolve them in 45 g of tetrahydrofuran, add 1 g of photoinitiator-1173, react under UV light at 80°C for 10 h; add 3 g of silicone oil, polyethylene glycol, 5.2 g of dioctyl phthalate and 0.4 g of UV-326, stir at room temperature for 36 h to obtain a low-temperature glue.

[0062] Comparative Example 1 A method for preparing a low-temperature adhesive for a double-layer composite adhesive tape, which is different from Example 3 in that ethylene glycol dimethacrylate is not added in step (1).

[0063] Comparative Example 2 A method for preparing a low-temperature adhesive for a double-layer composite adhesive tape, which is different from Example 3 in that allyl methyl succinate is not added in step (1).

[0064] Comparative Example 3 A method for preparing a low-temperature adhesive for a double-layer composite adhesive patch, which is different from Example 3 in that modified menthol is not added.

[0065] Comparative Example 4 A method for preparing a low-temperature adhesive for a double-layer composite adhesive tape, which is different from Example 3 in that modified dodecafluoroheptanoic acid is not added.

[0066] The low-temperature adhesive prepared in Examples 1 to 3 and Comparative Examples 1 to 4 was uniformly coated on the lower release paper 3, placed in a 40 to 50°C oven to dry for 1 to 2 h, and then covered with the upper release paper 1 to obtain a double-layer composite low-temperature adhesive tape with a structure as shown below. Figure 2 shown.

[0067] Performance test: According to the method in GB / T 4851, the initial adhesion, low-temperature 180° peeling force and holding force of the low-temperature adhesive in the double-layer composite low-temperature adhesive tape prepared in Examples 1 to 3 and Comparative Examples 1 to 4 were tested, and the waterproof performance was tested according to the method in GB / T 15330.

[0068] Table 1 Test results of initial adhesion and sustained adhesion of low temperature adhesive

[0069] According to the data in Table 1, the initial adhesion of the low-temperature adhesive prepared in Examples 1 to 3 is higher than that of the low-temperature adhesive prepared in Comparative Examples 1 to 4, and the long-lasting adhesion of the low-temperature adhesive prepared in Examples 1 to 3 is also higher than that of Comparative Examples 1 to 4, especially the long-lasting adhesion of the low-temperature adhesive of Example 3 reaches 10.23 h, while the long-lasting adhesion of Comparative Example 2 is only 0.68 h. Experimental proof. The embodiment adopts copolymerization of allyl methyl succinate, ethylene glycol dimethacrylate and bisphenol A (4-ethoxy-3,5-divinylphenyl) diglycidyl ether to effectively increase the crosslinking density of the polymer, carbon-carbon double bonds and ester groups and other active functional groups, effectively enhance the cohesion of the adhesive and the bonding force with the substrate surface, and the ester group has a certain polarity and can produce strong intermolecular forces with the substrate surface, such as hydrogen bonds or van der Waals forces, which helps to improve the bonding effect. Comparative Examples 1 and 2 both use a compound copolymerized with bisphenol A (4-ethoxy-3,5-divinylphenyl) diglycidyl ether, the polymer has fewer functional groups, the degree of polymerization is not as high as that of the embodiment system, the crosslinking density is relatively low, and the active functional groups are less, resulting in reduced viscosity.

[0070] Table 2 Low temperature adhesive 180° peel strength test results

[0071] According to the data in Table 2, the low-temperature adhesives prepared in Examples 1 to 3 have strong peeling force at temperatures ranging from room temperature to -40°C, that is, the adhesive stickers still have strong adhesion at low temperatures. The peeling force of the adhesive stickers prepared in Comparative Examples 1 to 4 is significantly weakened within the preset temperature range, that is, the adhesion is weak and it is easy to fall off when used in a low temperature environment.

[0072] Table 3 Test results of waterproof performance of double-layer composite adhesive tape

[0073] According to the data in Table 3, the low-temperature adhesives prepared in Examples 1 to 3 have good waterproof properties on both the plane and the step surface, while the low-temperature adhesives prepared in Comparative Examples 1 to 4 all have varying degrees of water seepage. Experiments have shown that the addition of silicon-modified menthol and silicon-modified dodecafluoroheptanoic acid polymers in the preparation methods of Examples 1 to 3 can effectively improve the hydrophobicity of the low-temperature adhesive. The menthol structure contains a hydrophobic long carbon chain and a hydrophilic hydroxyl group. Dodecafluoroheptanoic acid has a highly hydrophobic carbon chain. Menthol and dodecafluoroheptanoic acid are copolymerized, and the hydrophobic carbon chain of menthol can be embedded in the hydrophobic layer of dodecafluoroheptanoic acid to form a compact hydrophobic layer, reduce interfacial tension, and give the low-temperature adhesive excellent hydrophobic properties.

[0074] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a low-temperature adhesive for a double-layer composite adhesive tape, characterized in that: include: Step S1, adding allyl methyl succinate and ethylene glycol dimethacrylate into a solvent to dissolve, adding a photoinitiator, and reacting under UV light to obtain polymer A; Step S2, mixing bisphenol A (4-ethoxy-3,5-divinylphenyl) diglycidyl ether and polymer A, dissolving them in a good solvent, adding a photoinitiator, and reacting under UV light to obtain polymer B; Step S3, adding menthol and a silane coupling agent into a solvent and dissolving them to obtain a silylated menthol derivative; Step S4, adding menthol silylated derivative and polydimethylsiloxane into a solvent to dissolve, adding a catalyst, and reacting to obtain polymer C; Step S5, adding dodecafluoroheptanoic acid and a silane coupling agent into a solvent to dissolve, and reacting under nitrogen protection to obtain a silylated derivative of dodecafluoroheptanoic acid; Step S6, adding the silylated derivative of dodecafluoroheptanoic acid and copolymer C into a solvent to dissolve, adding a catalyst, and reacting to obtain polymer D; Step S7, adding polymer B and polymer D into a solvent to dissolve, adding a photoinitiator, reacting under UV light, adding a leveling agent, a dispersant, a plasticizer and an ultraviolet absorber after the reaction, stirring at room temperature to obtain a low-temperature glue.

2. The method for preparing a low-temperature adhesive for a double-layer composite adhesive tape according to claim 1, characterized in that: In the step S1, the mass ratio of allyl methyl succinate, ethylene glycol dimethacrylate, photoinitiator and solvent is 1: (0.6-0.7): (0.008-0.017): (4-5); the reaction temperature is 60-80° C., and the reaction time is 6-8 h.

3. The method for preparing a low-temperature adhesive for a double-layer composite adhesive tape according to claim 1, characterized in that: In the step S2, the good solvent is any one or more of dimethyl sulfoxide, cyclohexane, toluene, N, N'-dimethylformamide, ionic liquid and low eutectic solvent; the mass ratio of bisphenol A (4-ethoxy-3,5-divinylphenyl) diglycidyl ether, polymer A, photoinitiator and solvent is 1: (1-4): (0.01-0.05): (5-6); the reaction temperature is 70-90°C, and the reaction time is 20-24 h.

4. The method for preparing a low-temperature adhesive for a double-layer composite adhesive tape according to claim 1, characterized in that: In the step S3, the mass ratio of the menthol, silane coupling agent and solvent is 1: (0.5-1): (4-5); the reaction temperature is 100-120° C., and the reaction time is 4-6 h. In the step S4, the mass ratio of the polydimethylsiloxane, menthol siloxane derivative and solvent is 1: (1-3): (4-5); the reaction temperature is 60-100° C., and the reaction time is 10-12 h.

5. The method for preparing a low-temperature adhesive for a double-layer composite adhesive tape according to claim 1, characterized in that: In the step S5, the mass ratio of the dodecafluoroheptanoic acid, the silane coupling agent and the solvent is 1:(0.5-1):(4-5); the reaction temperature is 50-80° C., and the reaction time is 6-8 h.

6. The method for preparing a low-temperature adhesive for a double-layer composite adhesive tape according to claim 1, characterized in that: In the step S6, the mass ratio of the silylated derivative of dodecafluoroheptanoic acid, polymer C, catalyst and solvent is 1: (0.5-2): (0.0075-0.075): (4-5); the reaction temperature is 80-120° C., and the reaction time is 10-12 h.

7. The method for preparing a low-temperature adhesive for a double-layer composite adhesive tape according to claim 1, characterized in that: In the step S7, the leveling agent is any one or more of silicone oil and styrene maleic anhydride copolymer; the dispersant is polyethylene glycol; the plasticizer is any one or more of dioctyl phthalate and nonylphenoxyacetone; the ultraviolet absorber is any one or more of benzophenone, UV-P, and UV-326; and the stirring time is 24 to 36 hours.

8. The method for preparing a low-temperature adhesive for a double-layer composite adhesive tape according to claim 1, characterized in that: In the step S7, the mass ratio of the polymer B, polymer D, photoinitiator, solvent, dispersant, leveling agent, plasticizer and ultraviolet absorber is 1: (0.2-0.5): (0.01-0.05): (4-5): (0.05-0.1): (0.002-0.006): (0.26-0.52): (0.001-0.004); the reaction temperature is 60-80°C, and the reaction time is 10-16 h.

9. The method for preparing a low-temperature adhesive for a double-layer composite adhesive tape according to claim 1, characterized in that: The solvent is any one or more of methanol, toluene, xylene, acetone, acetonitrile, ethanol, dichloromethane, and tetrahydrofuran; the silane coupling agent is any one or more of 3-aminopropyltriethoxysilane, methacryloxypropyltrimethoxysilane, and vinyltriethoxysilane; the catalyst is any one or more of platinum catalyst, palladium catalyst, vanadium catalyst, iron catalyst, and nickel catalyst; the photoinitiator is any one or more of photoinitiator-1173, photoinitiator-184, TPO, TPO-L, IHT-PI 910, and initiator-907.

10. A double-layer composite low-temperature adhesive, characterized in that: The method is obtained by the preparation method according to any one of claims 1 to 9.

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