Reversible bonding double-sided adhesive tape based on photo-thermal response and preparation method of reversible bonding double-sided adhesive tape

Abstract

The invention provides a reversible adhesive double-sided tape based on photo-thermal response and a preparation method thereof, and relates to the technical field of functional adhesive materials. Comprising a transparent flexible supporting layer, a photo-thermal conversion layer is arranged below the transparent flexible supporting layer, a thermosensitive bonding layer is arranged below the photo-thermal conversion layer, the photo-thermal conversion layer is formed by compounding copper sulfide nanoflowers and polydopamine, the mass ratio of the copper sulfide nanoflowers to the polydopamine is 1: (0.2-0.5), and the thermo-sensitive bonding layer is arranged below the transparent flexible supporting layer. And the heat-sensitive adhesive layer comprises a polyurethane prepolymer containing a dynamic boric acid ester bond. Through collaborative design of the photo-thermal conversion layer and the dynamic bonding layer, the problems that an existing adhesive tape is irreversible in bonding, slow in response, poor in circularity and the like are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of functional adhesive materials, and in particular to a reversibly adhesive double-sided tape based on photothermal response and a preparation method thereof. Background Art

[0002] Double-sided tapes are widely used in electronic packaging, medical devices, automotive manufacturing, and other fields. Their adhesive properties directly affect product reliability and maintainability. Currently, double-sided tapes on the market primarily rely on physical adsorption (such as acrylic pressure-sensitive adhesives) or chemical cross-linking (such as epoxy resin tapes) to achieve adhesion, but these methods present the following challenges:

[0003] Irreversible adhesion makes it difficult to recycle materials: Traditional tapes usually require mechanical force or solvent assistance when peeling, which can easily lead to adhesive residue or damage to the substrate. During the disassembly of flexible electronic devices, tape residue may damage delicate circuits. High temperature or chemical peeling methods damage the substrate: Some hot-melt tapes (such as EVA-based tapes) need to be heated to above 120°C before peeling, but high temperatures may cause heat-sensitive materials (such as biosensors and organic thin-film transistors) to fail. Lack of controllable adhesion adjustment capabilities: The adhesion of existing tapes cannot be adjusted once solidified, and cannot adapt to application scenarios that require repeated bonding and peeling, such as temporary fixation and wearable device replacement.

[0004] To solve the irreversible adhesion problem of traditional tapes, researchers have developed a variety of stimulus-responsive adhesive materials, mainly including light-responsive adhesive materials and heat-responsive adhesive materials. Ultraviolet (UV) trigger system: such as azobenzene derivatives, which undergo cis-trans isomerization under ultraviolet light, causing the adhesive layer to soften. However, UV light has poor penetrability, and long-term exposure may cause material aging; visible light response system: such as spiropyran compounds, which can change adhesion under blue light, but the response speed is slow (>30 seconds) and the cycle stability is poor (<50 times). Thermosensitive hydrogel: such as poly (N-isopropylacrylamide) undergoes a phase change at around 32°C, but the mechanical strength of the hydrogel is low (<1kPa), and it needs to be heated as a whole, and local regulation cannot be achieved. Low-melting-point polymers: such as paraffin-doped pressure-sensitive adhesives, need to be heated to 60-80°C to soften, but the adhesion recovers slowly after cooling, making it difficult to meet the needs of fast operation.

[0005] In recent years, researchers have attempted to incorporate photothermal nanomaterials (such as carbon nanotubes and gold nanorods) into adhesive tapes to achieve contactless peeling through the photothermal effect. For example, carbon-based materials, such as carbon nanotubes, are used as photothermal agents, but the high conductivity of carbon materials can interfere with electronic devices, and uneven dispersion can easily lead to localized overheating. Metal nanoparticles, such as gold nanorods, can absorb near-infrared light, but their high cost (>500 yuan / gram) makes them difficult to commercialize.

[0006] Although photothermal responsive tapes have been studied, the following key issues still exist: slow response speed, most materials require continuous irradiation for more than 5 seconds to soften, which cannot meet the fast operation requirements of precision assembly; poor cycle stability, dynamic bonds (such as hydrogen bonds and coordination bonds) are easily broken after multiple cycles, resulting in a decrease in adhesion of more than 30%; limitations of photothermal materials, carbon nanotubes have strong conductivity, gold nanoparticles are expensive, copper sulfide (Cu 2-x Although S) is cheap, it is easily oxidized and its photothermal efficiency is unstable. Summary of the Invention

[0007] The present invention provides a reversibly adhesive double-sided tape based on photothermal response and a preparation method thereof. Through the coordinated design of a photothermal conversion layer and a dynamic adhesive layer, the problems of existing tapes such as irreversible adhesion, slow response, and poor recyclability are improved.

[0008] A reversibly adhesive double-sided tape based on photothermal response includes a transparent flexible support layer, a photothermal conversion layer is arranged below the transparent flexible support layer, and a thermosensitive adhesive layer is arranged below the photothermal conversion layer. The photothermal conversion layer is composed of a composite of copper sulfide nanoflowers and polydopamine, and the mass ratio of copper sulfide nanoflowers to polydopamine is 1:0.2-0.5. The thermosensitive adhesive layer includes a polyurethane prepolymer containing dynamic borate bonds.

[0009] The present invention uses polydopamine-coated copper sulfide nanoflowers as a high-stability photothermal conversion layer, which increases the photothermal conversion efficiency by more than 40%, which is three times the photothermal efficiency of traditional carbon materials, while enhancing the antioxidant property. The polyurethane grid based on dynamic borate ester cross-linking is used as a fast-response dynamic thermosensitive adhesive layer with a response time of less than 0.5 seconds, achieving millisecond-level adhesion regulation. The dynamic covalent bond design enables the adhesive tape to maintain an adhesion rate of more than 90% after 200 cycles; it improves the problems of irreversible adhesion, slow response, and poor recyclability of existing adhesive tapes.

[0010] Furthermore, the transparent flexible supporting layer includes one of polyimide and polyethylene terephthalate.

[0011] Furthermore, the polydopamine is coated on the copper sulfide nanoflower, and the coating thickness of the polydopamine is 5 to 20 nm.

[0012] Furthermore, the heat-sensitive adhesive layer further comprises 0.1 to 5 wt % of a thermochromic dye, and the color change temperature is 60 to 85° C.; the thermochromic dye comprises 1,3,3-trimethylindoline spiropyran or N-salicylic acid aldehyde aniline.

[0013] The color change temperature of the thermochromic dye is 60-85°C, which is consistent with the dissociation temperature of the dynamic borate bond, the response time is less than 0.5 seconds, and no side reaction occurs with polyurethane or borate bonds.

[0014] Furthermore, the polyurethane prepolymer containing dynamic borate bonds comprises the following components in parts by weight:

[0015] 50-70 parts of polytetrahydrofuran, 20-30 parts of hexamethylene diisocyanate, 5-15 parts of 3-aminophenylboric acid, 0.01-0.1 parts of dibutyltin dilaurate, and 10-20 parts of N,N-dimethylformamide; the Mn of the polytetrahydrofuran is 1000-2000.

[0016] Furthermore, the method for preparing the polyurethane prepolymer containing dynamic borate bonds comprises the following steps:

[0017] Step 1, polyol dehydration treatment: dehydrate polytetrahydrofuran in a vacuum at 95-105° C. for 1.5-2.5 hours, with a water content of <0.05%;

[0018] Step 2, prepolymerization reaction: under nitrogen protection, dehydrated polytetrahydrofuran is mixed with hexamethylene diisocyanate, dibutyltin dilaurate catalyst is added, and the mixture is reacted at 60-70° C. for 2.5-3.5 hours to obtain an isocyanate-terminated polyurethane prepolymer;

[0019] Step 3, dynamic bond introduction: dissolve 3-aminophenylboronic acid in N,N-dimethylformamide, add dropwise to the above polymer, and continue the reaction at 60-65°C for 1.5-2.5 hours;

[0020] Step 4: Termination of the reaction: Add 1-2 wt% ethanol to terminate the reaction.

[0021] The present invention uses 3-aminophenylboronic acid, whose amino group (-NH2) reacts with the prepolymer -NCO to form a stable urea bond (-NH-CO-NH-), while retaining the boronic acid group (-B(OH)2) for subsequent dynamic cross-linking, avoiding side reactions (such as gelation) caused by the direct participation of boric acid in the prepolymer reaction. The existing technology uses disulfide bond dynamic cross-linking, which requires redox triggering, while the present invention only requires heat / photothermal stimulation.

[0022] The combination of polytetramethylene diisocyanate (PTMG, Mn = 1000-2000) and hexamethylene diisocyanate (HDI) is selected. Its linear molecular chain structure gives the tape high flexibility (elongation at break > 300%). The traditional solution uses polyether polyols, which easily leads to a too soft adhesive layer (G' < 10 3 Pa).

[0023] In step 1, the dehydration temperature is limited to 95-105°C and the water content is less than 0.05% to prevent trace water from reacting with -NCO to form CO2, which can cause bubble defects. In step 2, the NCO:OH ratio is controlled to 1.5:1, ensuring that the prepolymer end groups are -NCO (no excess -OH), providing precise reaction sites for subsequent APBA introduction. In step 3, the reaction temperature is 60-65°C, significantly lower than the borate ester dissociation temperature (80°C), preventing premature crosslinking. The prepolymer contains both urea bonds, which have high bond energy and provide mechanical strength, and borate bonds, which have low bond energy and achieve reversibility.

[0024] A method for preparing a reversibly adhesive double-sided tape based on photothermal response comprises the following steps:

[0025] S100, preparing copper sulfide nanoflowers: reacting a copper salt, a sulfur source, and a surfactant at 160-180° C. for 6-12 hours to obtain copper sulfide nanoflowers;

[0026] S200, polydopamine coating: Disperse copper sulfide nanoflowers in Tris-HCl buffer, add dopamine hydrochloride, and stir for 2-4 hours to form a copper sulfide-polydopamine complex;

[0027] S300, coating a light-to-heat conversion layer: mixing a copper sulfide-polydopamine complex with waterborne polyurethane, coating the mixture on the surface of the support layer, and drying the mixture to form a light-to-heat conversion layer;

[0028] S400, preparing a thermosensitive adhesive layer: uniformly mixing a polyurethane prepolymer containing a dynamic borate bond and a thermochromic dye, coating the mixture on the light-to-heat conversion layer, and UV curing the mixture for 30-60 seconds to form an adhesive layer.

[0029] Traditional photothermal materials use carbon nanotubes, which have problems of conductive interference and uneven dispersion. However, copper sulfide nanoflowers have a porous structure with a specific surface area of >100m 2 / g, and coated with polydopamine with a thickness of 5-20nm, achieving a near-infrared absorption rate of >95%, improved antioxidant properties, and an efficiency attenuation of <8% after 200 cycles.

[0030] The present invention realizes localized photothermal triggered peeling through the reversible dissociation of borate ester bonds (modulus drops by 2 orders of magnitude at 80°C). Thermochromic dye visualization: Thermochromic dye changes color at 60-85°C, visually showing the bonding state; 50-100mW / cm 2 UV light triggers the pre-crosslinking of borate bonds. The boronic acid groups react with the polyols in the adhesive layer or the catechol groups from polydopamine to form a reversible crosslinked network. The borate bonds dissociate at 80°C and spontaneously reassemble at room temperature.

[0031] Furthermore, in step S100, the molar ratio of the copper salt to the sulfur source is 1:1.2-1.8, the mass ratio of the surfactant to the copper salt is 1:1-5, and the pH of the reaction solution is 6-9.

[0032] Furthermore, in step S100, the copper salt is selected from at least one of copper chloride, copper sulfate or copper acetate, the sulfur source is selected from at least one of sodium sulfide, thioacetamide or L-cysteine, and the surfactant is selected from polyvinyl pyrrolidone or polyethylene glycol.

[0033] Furthermore, in step S300, the light-to-heat conversion layer is coated by a slit coating or spray coating process, and the drying temperature is 60-80°C.

[0034] Reversible bonding method based on photothermal response:

[0035] 1. Bonding stage

[0036] Step 1: Tape Lamination: Double-sided tape is applied to the target substrate (such as glass, flexible circuit or skin), and a pressure of 0.1-1 MPa is applied for 5-10 seconds to ensure that the heat-sensitive adhesive layer is in full contact with the substrate; the thermochromic dye remains colorless, indicating a "ready state".

[0037] Step 2: Bonding enhancement: Use low-power near-infrared light (800-900nm, 0.1-0.5W / cm 2 ) for 1-2 seconds to raise the temperature of the light-to-heat conversion layer to 40-50°C; avoid exceeding 60°C (the dye discoloration threshold).

[0038] 2. Stripping stage

[0039] Trigger peeling: Increase the power of the same near-infrared light source to ≥1W / cm 2 , focus irradiation on the area to be peeled off, the spot diameter can be adjusted to 1-5mm, the photothermal layer absorbs NIR light and quickly heats up to 80-100℃, the thermochromic dye changes color and can be quickly peeled off.

[0040] 3. Recycle

[0041] Step 1. Adhesion recovery: After stopping the light, the tape is cooled at room temperature for 10-20 seconds. The borate ester bonds spontaneously reorganize and the adhesion returns to the initial value.

[0042] Step 2: Status reset: The thermochromic dye returns to colorless at a temperature < 60°C, indicating that it can be used again.

[0043] Reversible bonding principle based on photothermal response: Bonding stage: Dynamic borate bonds form a stable cross-linked network at room temperature (25°C) (storage modulus G'=10 4 -10 5Pa), generating 8-10N / cm 2 Initial adhesion; Adhesion strengthening: Slightly increasing the temperature enhances the movement of polyurethane chain segments, promoting molecular-level contact between the adhesive layer and the substrate, and improving adhesion by about 20%; Triggered peeling: The photothermal layer absorbs NIR light and rapidly heats to 80-100°C at a heating rate of >50°C / second; Dynamic borate ester bond dissociation (G' drops to 102-103Pa), and adhesion drops by >99% to <0.1N / cm 2 .

[0044] Advantageous Effects of the Invention

[0045] 1. The present invention adopts the coordinated setting of copper sulfide nanoflower-polydopamine composite photothermal layer and dynamic borate bond adhesive layer, combined with low temperature controllable process, to obtain a double-sided tape with a resistance of 8.5-10N / cm 2 High initial adhesion (25°C); Fast photothermal response: 0.3 to 0.5 seconds of near-infrared light (808nm) can reduce the adhesion by 99% (to <0.1N / cm 2 ), achieving millisecond-level non-contact peeling; repeated use of more than 200 times, the adhesion retention rate is >90%, far exceeding traditional tapes; the photothermal layer has excellent oxidation resistance, and the efficiency decay is <5% after 200 cycles; the thermochromic dye changes color at 60-85℃, displaying the bonding status in real time to avoid misoperation.

[0046] 2. The present invention has a wide range of application adaptability: precision electronic assembly, local light peeling without damaging flexible circuits; wearable devices / medical dressings, body temperature-triggered color change prompts replacement, biocompatible materials, no heavy metals; robotic grasping, response speed of 0.5 seconds, 10 times faster than pneumatic suction cups, and no residue.

[0047] Tris-HCl: tris(hydroxymethyl)aminomethane hydrochloride. DETAILED DESCRIPTION

[0048] Example 1 Copper sulfide nanoflowers have a porous three-dimensional structure with a specific surface area of 50 to 150 m2

[0049] The preparation method of a polyurethane prepolymer containing a dynamic borate ester bond comprises the following steps:

[0050] Step 1: 60 g of polytetrahydrofuran (Mn=2000) was vacuum dehydrated at 100° C. for 2 hours to a water content of 0.02%;

[0051] Step 2: Under nitrogen protection, the dehydrated polytetrahydrofuran was mixed with 25 g of hexamethylene diisocyanate, 0.03 g of dibutyltin dilaurate catalyst was added, and the mixture was reacted at 70° C. for 3 hours to obtain an isocyanate-terminated polyurethane prepolymer;

[0052] Step 3: Dissolve 8g of 3-aminophenylboronic acid in 15g of N,N-dimethylformamide, add dropwise to the above polymer, and continue the reaction at 63°C for 2 hours;

[0053] Step 4: Add 1 wt% ethanol to terminate the reaction.

[0054] Example 2

[0055] The preparation method of a polyurethane prepolymer containing a dynamic borate ester bond comprises the following steps:

[0056] Step 1: Dehydrate 50 g of polytetrahydrofuran in a vacuum oven at 95° C. for 1.5 hours to a water content of 0.04%;

[0057] Step 2: Under nitrogen protection, the dehydrated polytetrahydrofuran was mixed with 20 g of hexamethylene diisocyanate, 0.01 g of dibutyltin dilaurate catalyst was added, and the mixture was reacted at 60° C. for 3.5 hours to obtain an isocyanate-terminated polyurethane prepolymer;

[0058] Step 3: Dissolve 5g of 3-aminophenylboronic acid in 10g of N,N-dimethylformamide, add dropwise to the above polymer, and continue the reaction at 65°C for 1.5 hours;

[0059] Step 4: Termination of the reaction: Add 2 wt% ethanol to terminate the reaction.

[0060] Example 3

[0061] The preparation method of a polyurethane prepolymer containing a dynamic borate ester bond comprises the following steps:

[0062] Step 1: 70 g of polytetrahydrofuran (Mn=2000) was vacuum dehydrated at 105° C. for 2.5 hours to a water content of 0.01%;

[0063] Step 2: Under nitrogen protection, the dehydrated polytetrahydrofuran was mixed with 30 g of hexamethylene diisocyanate, 0.1 g of dibutyltin dilaurate catalyst was added, and the mixture was reacted at 65° C. for 3.5 hours to obtain an isocyanate-terminated polyurethane prepolymer;

[0064] Step 3: Dissolve 15g of 3-aminophenylboronic acid in 20g of N,N-dimethylformamide, add dropwise to the above polymer, and continue the reaction at 60°C for 2.5 hours;

[0065] Step 4: Add 1.5 wt% ethanol to terminate the reaction.

[0066] Comparative Example 1

[0067] Without 3-aminophenylboronic acid, other steps and parameters are the same as those in Example 1.

[0068] Comparative Example 2

[0069] Phenylboronic acid was used instead of 3-aminophenylboronic acid, and other steps and parameters were the same as those in Example 1.

[0070] Comparative Example 3

[0071] In step 1, the water content is 0.1%, and the other steps and parameters are the same as those in Example 1.

[0072] Comparative Example 4

[0073] The reaction temperature in step 3 is 80° C., and the other steps and parameters are the same as those in Example 1.

[0074] Comparative Example 5

[0075] There is no dynamic key introduction in step 3, and other steps and parameters are the same as those in Example 1.

[0076] The performance parameters of the prepolymers prepared by the methods of Examples 1-3 and Comparative Examples 1-5 are shown in Table 1.

[0077] Table 1 Performance parameters of prepolymers prepared by the methods of Examples 1-3 and Comparative Examples 1-5

[0078]

[0079] Note: N / A means not applicable or no relevant data.

[0080] As shown in Table 1, the adhesion loss of the prepolymers in Examples 1-3 at 80°C was greater than 99%, the response time was as low as 0.3 seconds, and the adhesion retention rate reached 95% after 200 cycles. The prepolymer prepared in Example 1 performed the best. Comparative Examples 1 and 5, both of which lack dynamic bonds, exhibited significantly lower adhesion loss at 80°C than that of Example 1. Comparative Example 2, in which phenylboronic acid replaces 3-aminophenylboronic acid, achieved a dynamic bond density of 0.7 mmol / L. The amino group of 3-aminophenylboronic acid in Example 1 participates in the formation of urea bonds, resulting in a dynamic bond density of 1.1 mmol / L, a 57% increase compared to Comparative Example 2 and a 20% improvement in cycling stability. The insufficient dehydration of polytetrahydrofuran in Comparative Example 3 resulted in bubbles in the prepolymer and significantly lower adhesion. The high-temperature reaction in Comparative Example 4 rendered some borate ester bonds irreversible, resulting in a 45% decrease in cycling performance.

[0081] The polyurethane prepolymers containing dynamic borate bonds used in Examples 4-6 were all prepared using the method of Example 1.

[0082] Example 4

[0083] A method for preparing a reversibly adhesive double-sided tape based on photothermal response comprises the following steps:

[0084] S100, preparation of copper sulfide nanoflowers: 0.1 mmol copper chloride, 0.15 mmol thioacetamide, and 6.72 g polyvinyl pyrrolidone were reacted at 180°C for 12 hours, pH = 7.5, to obtain three-dimensional porous copper sulfide nanoflowers with a particle size of 150 ± 20 nm;

[0085] S200, polydopamine coating: 10 mg of copper sulfide nanoflowers were dispersed in Tris-HCl buffer, pH = 8.5, 3 mg of dopamine hydrochloride was added, and stirred for 3 hours to form a copper sulfide-polydopamine complex. The polydopamine coating thickness was 10 nm.

[0086] S300, coating a light-to-heat conversion layer: mixing a copper sulfide-polydopamine complex with 64 mg of waterborne polyurethane, coating the mixture on the surface of the support layer using a slit coating method, and drying the mixture at 70° C. for 20 minutes to form a light-to-heat conversion layer;

[0087] S400, preparing a heat-sensitive adhesive layer: uniformly mixing the polyurethane prepolymer containing dynamic borate bonds prepared in Example 1 with 1 wt% of 1,3,3-trimethylindoline spiropyran, coating the mixture on the light-to-heat conversion layer, and UV curing at 80 mW / cm 2 , 365nm, 45 seconds, forming an adhesive layer with a thickness of 50μm.

[0088] Example 5

[0089] A method for preparing a reversibly adhesive double-sided tape based on photothermal response comprises the following steps:

[0090] S100, preparation of copper sulfide nanoflowers: 0.1 mmol copper sulfate, 0.12 mmol sodium sulfide, and 4.48 g polyethylene glycol (PEG-2000) were reacted at 160°C for 8 hours, pH = 8, to obtain sheet-like assembled copper sulfide nanoflowers with a particle size of 200 ± 30 nm;

[0091] S200, polydopamine coating: 10 mg of copper sulfide nanoflowers were dispersed in Tris-HCl buffer, pH = 8.5, and 6.2 mg of dopamine hydrochloride was added. The mixture was stirred for 4 hours to form a copper sulfide-polydopamine complex. The polydopamine coating thickness was 5 nm.

[0092] S300, coating a light-to-heat conversion layer: mixing a copper sulfide-polydopamine complex with 48 mg of waterborne polyurethane, applying the mixture on the surface of the support layer by spraying, and drying at 60° C. for 30 minutes to form a light-to-heat conversion layer;

[0093] S400, preparing a heat-sensitive adhesive layer: uniformly mix the polyurethane prepolymer containing dynamic borate bonds prepared in Example 1 with 0.5 wt% of N-salicylic acid aldehyde aniline, apply it on the light-to-heat conversion layer, and UV cure it at 60 mW / cm2 , 365nm, 50 seconds, forming an adhesive layer with a thickness of 45μm.

[0094] Example 6

[0095] A method for preparing a reversibly adhesive double-sided tape based on photothermal response comprises the following steps:

[0096] S100, preparation of copper sulfide nanoflowers: 0.1 mmol copper acetate, 0.18 mmol L-cysteine and 13.45 polyvinylpyrrolidone were reacted at 170°C for 10 hours, pH = 6.5, to obtain ultrathin petal-shaped copper sulfide nanoflowers with a particle size of 45 ± 3 nm;

[0097] S200, polydopamine coating: 10 mg of copper sulfide nanoflowers were dispersed in Tris-HCl buffer, pH = 8.5, 2.5 mg of dopamine hydrochloride was added, and stirred for 2 hours to form a copper sulfide-polydopamine complex. The polydopamine coating thickness was 20 nm.

[0098] S300, coating a light-to-heat conversion layer: mixing a copper sulfide-polydopamine complex with 25 mg of waterborne polyurethane, coating the mixture on the surface of the support layer by slit coating, and drying the mixture at 80° C. for 15 minutes to form a light-to-heat conversion layer;

[0099] S400, preparing a heat-sensitive adhesive layer: uniformly mixing the polyurethane prepolymer containing dynamic borate bonds prepared in Example 1 with 2 wt% of 1,3,3-trimethylindoline spiropyran, coating the mixture on the light-to-heat conversion layer, and UV curing at 100 mW / cm 2 , 365nm, 30 seconds, forming an adhesive layer with a thickness of 55μm.

[0100] Comparative Example 6

[0101] No surfactant is added in step S100, and other steps and parameters are the same as those in Example 4.

[0102] Comparative Example 7

[0103] Dopamine hydrochloride is not added in step S200, and other steps and parameters are the same as those in Example 4.

[0104] Comparative Example 8

[0105] Ordinary polyurethane (without dynamic bonds) is used in step S400, and other steps and parameters are the same as those in Example 4.

[0106] Comparative Example 9

[0107] The reaction temperature in step S100 is 140° C., and the other steps and parameters are the same as those in Example 4.

[0108] Comparative Example 10

[0109] In step S400 , no thermochromic dye is added, and other steps and parameters are the same as those in Example 4.

[0110] The performance parameters of the double-sided tapes prepared by the methods of Examples 4-6 and Comparative Examples 6-10 are shown in Table 1.

[0111] Table 1 Performance parameters of double-sided tapes prepared by the methods of Examples 4-6 and Comparative Examples 6-10

[0112] Test indicators Example 4 Example 5 Example 6 Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 Comparative Example 10 Near infrared absorption rate (%) 96 94 98 85 92 95 78 96 <![CDATA[Initial adhesion force (N / cm 2 )]]> 9.3 9.2 9.4 6.2 8.0 6.5 5.8 8.5 <![CDATA[Adhesion force at 80°C (N / cm 2 )]]> 0.03 0.03 0.02 0.5 0.3 5.8 1.2 0.03 Response time (seconds) 0.2 0.3 0.2 1.2 0.8 N / A 1.5 0.4 Adhesion retention after 200 cycles (%) 96 95 98 65 70 30 60 92 Color change contrast (ΔE) 35 28 40 - - - - N / A

[0113] Note: N / A means not applicable or no relevant data.

[0114] As shown in Table 2, the double-sided tapes prepared in Comparative Examples 4-6 have a near-infrared absorption rate of up to 98% and an initial adhesion force of up to 9.4 N / cm 2 At 80℃, the adhesion can be reduced to 0.02N / cm 2 , the fastest response time was 0.2 seconds, and the adhesion retention rate reached 98% after 200 cycles. In Comparative Example 6, no surfactant was added in step S100, causing the copper sulfide nanoflowers to agglomerate and overall performance to deteriorate. In Comparative Example 7, no dopamine hydrochloride was added in step S200, resulting in no polydopamine coating and severe oxidation. In Comparative Example 8, ordinary polyurethane (without dynamic bonds) was used in step S400, making it impossible to achieve photothermal control. In Comparative Example 9, the reaction temperature in step S100 was 140°C, which was too low, resulting in insufficient crystallinity. In Comparative Example 10, no thermochromic dye was added, resulting in inability to visualize.

Claims

1. A reversible adhesive double-sided tape based on photothermal response, characterized in that: It comprises a transparent flexible supporting layer, a light-to-heat conversion layer is provided below the transparent flexible supporting layer, and a heat-sensitive adhesive layer is provided below the light-to-heat conversion layer. The light-to-heat conversion layer is composed of a composite of copper sulfide nanoflowers and polydopamine, the mass ratio of the copper sulfide nanoflowers to polydopamine is 1:0.2-0.5, and the heat-sensitive adhesive layer includes a polyurethane prepolymer containing a dynamic borate bond.

2. The reversible adhesive double-sided tape based on photothermal response according to claim 1, characterized in that: The transparent flexible support layer includes one of polyimide or polyethylene terephthalate.

3. The reversible adhesive double-sided tape based on photothermal response according to claim 1, characterized in that: The polydopamine is coated on the copper sulfide nanoflower, and the coating thickness of the polydopamine is 5 to 20 nm.

4. The reversible adhesive double-sided tape based on photothermal response according to claim 1, characterized in that: The heat-sensitive adhesive layer further comprises 0.1-5 wt % of a thermochromic dye, and the color change temperature is 60-85° C. The thermochromic dye comprises 1,3,3-trimethylindoline spiropyran or N-salicylic acid aldehyde aniline.

5. The reversible adhesive double-sided tape based on photothermal response according to claim 1, characterized in that: The polyurethane prepolymer containing dynamic borate bonds comprises the following components in parts by weight: 50-70 parts of polytetrahydrofuran, 20-30 parts of hexamethylene diisocyanate, 5-15 parts of 3-aminophenylboric acid, 0.01-0.1 parts of dibutyltin dilaurate, and 10-20 parts of N,N-dimethylformamide; the Mn of the polytetrahydrofuran is 1000-2000.

6. The reversible adhesive double-sided tape based on photothermal response according to claim 5, characterized in that: The method for preparing the polyurethane prepolymer containing dynamic borate bonds comprises the following steps: Step 1, polyol dehydration treatment: dehydrate polytetrahydrofuran in a vacuum at 95-105° C. for 1.5-2.5 hours, with a water content of <0.05%; Step 2, prepolymerization reaction: under nitrogen protection, dehydrated polytetrahydrofuran is mixed with hexamethylene diisocyanate, dibutyltin dilaurate catalyst is added, and the mixture is reacted at 60-70° C. for 2.5-3.5 hours to obtain an isocyanate-terminated polyurethane prepolymer; Step 3, dynamic bond introduction: dissolve 3-aminophenylboronic acid in N,N-dimethylformamide, add dropwise to the above polymer, and continue the reaction at 60-65°C for 1.5-2.5 hours; Step 4: Termination of the reaction: Add 1-2 wt% ethanol to terminate the reaction.

7. The method for preparing a photothermal responsive reversible adhesive double-sided tape according to any one of claims 1 to 6, wherein: The following steps are involved: S100, preparing copper sulfide nanoflowers: reacting a copper salt, a sulfur source, and a surfactant at 160-180° C. for 6-12 hours to obtain copper sulfide nanoflowers; S200, polydopamine coating: Disperse copper sulfide nanoflowers in Tris-HCl buffer, add dopamine hydrochloride, and stir for 2-4 hours to form a copper sulfide-polydopamine complex; S300, coating a light-to-heat conversion layer: mixing a copper sulfide-polydopamine complex with waterborne polyurethane in a mass ratio of 1:3-5, coating the mixture on the surface of the support layer, and drying the mixture to form a light-to-heat conversion layer; S400, preparing a thermosensitive adhesive layer: uniformly mixing a polyurethane prepolymer containing a dynamic borate bond and a thermochromic dye, coating the mixture on the light-to-heat conversion layer, and UV curing the mixture for 30-60 seconds to form an adhesive layer.

8. The preparation method according to claim 7, characterized in that In step S100, the molar ratio of the copper salt to the sulfur source is 1:1.2-1.8, the mass ratio of the surfactant to the copper salt is 1:1-5, and the pH of the reaction solution is 6-9.

9. The preparation method according to claim 7, characterized in that In step S100, the copper salt is selected from at least one of copper chloride, copper sulfate or copper acetate, the sulfur source is selected from at least one of sodium sulfide, thioacetamide or L-cysteine, and the surfactant is selected from polyvinyl pyrrolidone or polyethylene glycol.

10. The preparation method according to claim 7, characterized in that In step S300, the light-to-heat conversion layer is coated by a slit coating or spray coating process, and the drying temperature is 60-80°C.

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