Thermally induced large-span reversible adhesive glue material, preparation method and application thereof

Abstract

The application belongs to the technical field of adhesive materials, and particularly relates to a heat-induced large-span reversible adhesive material and a preparation method and application thereof. The heat-induced large-span reversible adhesive material provided by the application comprises the following raw materials: a pentaerythritol acrylate monomer, an O,O'-di(2-aminopropyl)polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol monomer, a dopamine hydrochloride monomer, a disulfide bond urea-based olefin monomer, an acid-binding agent and an organic solvent. The heat-induced large-span reversible adhesive material comprises a disulfide bond, a urea group and a catechol structure. The bonding strength of the heat-induced large-span reversible adhesive material provided by the application is much higher than that of common reversible adhesives, the bonding strength span of reversible adhesion is large (from 0.04 MPa to 6.45 MPa), the switching time of reversible adhesion is short (<1 min), the cycle number of stable reversible adhesion is as high as 100, the heat-induced large-span reversible adhesive material can be used for bonding various substrates, and has considerable market application prospect.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of adhesive materials, and particularly relates to a heat-induced large-span reversible adhesive material and a preparation method and application thereof. BACKGROUND

[0002] Common high molecular adhesives are generally based on chemical crosslinking of groups to form covalent bond structures, which lose reworkability after curing, making the disassembly or recycling process difficult. At present, the bonding strength of irreversible adhesives can reach 5-15 MPa. However, such adhesives cannot be recycled and are not environmentally friendly, resulting in a large waste of fossil energy. Reversible adhesive materials are widely used in many engineering fields such as the automotive industry, electronic devices, medical surgery, and intelligent grabbing. Such adhesive materials have a certain bonding strength, can withstand external forces, and can be detached according to needs with less damage to the adherend. The reversible adhesive material overcomes the defect that the thermosetting adhesive cannot be recycled and reused after curing.

[0003] At present, the bonding strength of commercially available reversible adhesives is relatively low. Moreover, the commercially available reversible adhesives have a small number of reversible adhesion cycles and a small span of reversible adhesion bonding strength, and a long switching time of reversible adhesion, which is difficult to meet the needs of actual applications. SUMMARY

[0004] Therefore, the purpose of the present application is to provide a heat-induced large-span reversible adhesive material and a preparation method and application thereof. The heat-induced large-span reversible adhesive material provided by the present application has ultrahigh bonding strength, a large span of reversible adhesion bonding strength, a short switching time of reversible adhesion, and a reversible adhesion cycle of 100 times.

[0005] The present application provides a heat-induced large-span reversible adhesive material, which is prepared from the following raw materials:

[0006] a pentaerythritol-based acrylate monomer, an O,O'-bis(2-aminopropyl)polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol monomer, a dopamine hydrochloride monomer, a disulfide urea-based olefin monomer, an acid-binding agent, and an organic solvent.

[0007] The heat-induced large-span reversible adhesive material includes a disulfide bond, a urea group, and a catechol structure.

[0008] Preferably, the pentaerythritol-based acrylate monomer includes one or more of pentaerythritol tetraacrylate, pentaerythritol triacrylate, and polydipentaerythritol hexaacrylate.

[0009] Preferably, the weight average molecular weight of the O,O'-bis(2-aminopropyl) polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol monomer is 500-1000.

[0010] Preferably, the disulfide bond urea-based olefin monomer comprises one or more of the following structures:

[0011]

[0012] Preferably, the molar ratio of the pentaerythritol-based acrylate monomer, the O,O'-bis(2-aminopropyl) polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol monomer, the dopamine hydrochloride monomer, and the disulfide bond urea-based olefin monomer is 1:(1-2):(1-3.5):(1-2);

[0013] The molar ratio of the acid-binding agent to the dopamine hydrochloride monomer is (1-2):1.

[0014] Preferably, the acid-binding agent is an organic base-based acid-binding agent;

[0015] The organic base-based acid-binding agent is triethylamine;

[0016] The organic solvent comprises one or more of N,N-dimethylformamide, ethyl acetate, butyl acetate, acetone, butanone, cyclohexanone, tetrahydrofuran, ethylene glycol ethyl ether acetate, propylene glycol ethyl ether acetate, and dimethyl sulfoxide.

[0017] The present application also provides a preparation method of the heat-induced large-span reversible adhesive material described in the above technical solution, comprising the following preparation steps:

[0018] The pentaerythritol-based acrylate monomer, the O,O'-bis(2-aminopropyl) polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol monomer, the dopamine hydrochloride monomer, the disulfide bond urea-based olefin monomer, and the organic solvent are mixed and stirred to obtain a prepolymer mixture;

[0019] The prepolymer mixture is mixed with the acid-binding agent to perform a Michael addition reaction to obtain the heat-induced large-span reversible adhesive material.

[0020] Preferably, the temperature of the Michael addition reaction is 65-95°C, and the time is 3-6h.

[0021] The present application also provides an application of the heat-induced large-span reversible adhesive material described in the above technical solution or the heat-induced large-span reversible adhesive material prepared by the preparation method in the bonding of plastics, glass, metal, and wood.

[0022] Preferably, the specific mode of the application comprises the following steps:

[0023] The heat-induced large-span reversible adhesive glue material is heated to form a glue solution, which is coated on the surface of a substrate and solidified after being attached;

[0024] The temperature of the heating is greater than or equal to 100 DEG C.

[0025] The solidification temperature is room temperature 25 DEG C plus or minus 5 DEG C, and the solidification time is 10 to 20 hours.

[0026] The application provides a heat-induced large-span reversible adhesive glue material, which comprises the following preparation raw materials: a pentaerythritol acrylate monomer, an O, O'-di(2-aminopropyl) polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol monomer, a dopamine hydrochloride monomer, a disulfide bond urea-based olefin monomer, an acid-binding agent and an organic solvent; the heat-induced large-span reversible adhesive glue material comprises a disulfide bond, a urea group and a catechol structure.

[0027] The four functional monomers are selected as raw materials for preparation, the pentaerythritol acrylate monomer is used as a branched group, which can make the polymer of the heat-induced large-span reversible adhesive material grow in a star-shaped branched manner, form a branched structure, and facilitate the exposure of the adhesive group (catechol structure) in the dopamine hydrochloride monomer, and the viscosity of the polymer containing the branched structure is low. Moreover, the branched polymer with low viscosity endows the heat-induced large-span reversible adhesive material with good wettability, which is more conducive to the adhesion with different types of materials to be bonded, and improves the bonding strength. The O,O'-bis(2-aminopropyl) polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol monomer is used as a chain extender, which can increase the molecular weight of the polymer of the heat-induced large-span reversible adhesive material, increase the flexibility of the polymer molecular chain, thereby improving the bonding strength of the heat-induced large-span reversible adhesive material, and expanding the span of the reversible adhesive bonding strength. The dopamine hydrochloride monomer is used as a functional monomer for providing bonding strength, which contains a catechol structure and can interact with various materials to be bonded, and endows the heat-induced large-span reversible adhesive material with good interfacial adhesion performance. The amino structure in the dopamine hydrochloride monomer and the O,O'-bis(2-aminopropyl) polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol monomer can undergo a Michael addition reaction with the pentaerythritol acrylate monomer and the disulfide bond urea-based olefin monomer. The disulfide bond urea-based olefin monomer is used as a reversible adhesive dynamic regulator, which is rich in hydrogen bonds and disulfide bonds. The two dynamic bonds can play a role in regulating the chain breaking and reconfiguration of the polymer of the heat-induced large-span reversible adhesive material, and are the key to realizing reversible adhesion. In the present application, the disulfide bond urea-based olefin monomer contains a urea group, which can form a large number of hydrogen bonds, increase the internal bonding strength of the polymer of the heat-induced large-span reversible adhesive material, and further increase the bonding strength of the heat-induced large-span reversible adhesive. Moreover, the disulfide bond and the hydrogen bond begin to break during heating, and completely break to become a liquid state at a temperature above 100℃. When the temperature decreases to room temperature, the disulfide bond and the hydrogen bond are reconfigured and restored, realizing the reversible adhesion of the heat-induced large-span reversible adhesive material, and the bonding strength can still remain high after multiple heating and cooling cycles.

[0028] The results of the examples show that the bonding strength of the heat-induced large-span reversible adhesive material provided by the present application reaches 6.45 MPa, which is much higher than the bonding strength (about 3 MPa) of common reversible adhesives, the bonding strength span of reversible adhesion is large (from 0.04 MPa to 6.45 MPa), the switching time of reversible adhesion is short (30 s, <1 min), and the cycle number of stable reversible adhesion is as high as 100 times, and the bonding strength of the 100th repeated cycle adhesion test still reaches 4.0 MPa, indicating that the heat-induced large-span reversible adhesive material provided by the present application has stable performance, high bonding strength, can be used for bonding various substrates, and has universality.

[0029] The application provides a preparation method of the heat-induced large-span reversible adhesive material, and the preparation method comprises the following steps: mixing and stirring a pentaerythritol acrylate monomer, an O,O'-di(2-aminopropyl) polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol monomer, a dopamine hydrochloride monomer, a disulfide bond urea-based olefin monomer and an organic solvent to obtain a prepolymer mixture; mixing the prepolymer mixture with an acid binding agent to perform a Michael addition reaction, so as to obtain the heat-induced large-span reversible adhesive material.

[0030] The preparation method provided by the application has simple steps, does not need to add various auxiliary agents, has low cost, is easy to produce industrially, and has considerable market application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 A nuclear magnetic hydrogen spectrum of the disulfide bond urea-based olefin monomer A prepared in Example 1;

[0032] Figure 2 A nuclear magnetic carbon spectrum of the disulfide bond urea-based olefin monomer A prepared in Example 1;

[0033] Figure 3 A nuclear magnetic hydrogen spectrum of the heat-induced large-span reversible adhesive prepared in Example 1;

[0034] Figure 4 A Raman spectrum of the heat-induced large-span reversible adhesive prepared in Example 1;

[0035] Figure 5 A schematic diagram of a bonding strength test of the heat-induced large-span reversible adhesive prepared in Example 1;

[0036] Figure 6 A bonding strength diagram of the heat-induced large-span reversible adhesive prepared in Example 1 after 100 cycles of repeated adhesion. DETAILED DESCRIPTION

[0037] The application provides a heat-induced large-span reversible adhesive material, which comprises the following preparation raw materials:

[0038] The heat-induced large-span reversible adhesive material comprises a pentaerythritol acrylate monomer, an O,O'-di(2-aminopropyl) polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol monomer, a dopamine hydrochloride monomer, a disulfide bond urea-based olefin monomer, an acid binding agent and an organic solvent.

[0039] In the application, the raw materials used in the application are preferably commercially available products, unless otherwise specified.

[0040] The preparation raw material of the heat-induced large-span reversible adhesive glue material provided by the present application comprises a pentaerythritol acrylate monomer, preferably one or more of pentaerythritol tetraacrylate, pentaerythritol triacrylate and polydipentaerythritol hexaacrylate, and more preferably pentaerythritol tetraacrylate.

[0041] The present application uses a pentaerythritol acrylate monomer as a branched group, which can make the polymer of the heat-induced large-span reversible adhesive glue material grow in a star-shaped branched manner to form a branched structure, which is conducive to exposing the adhesive group (catechol structure) in the dopamine hydrochloride monomer, and the polymer containing the branched structure has a lower viscosity. The branched polymer with a lower viscosity gives the heat-induced large-span reversible adhesive glue material good wettability, which is more conducive to the adhesion with different types of materials to be bonded and improves the bonding strength.

[0042] The preparation raw material of the heat-induced large-span reversible adhesive glue material provided by the present application comprises an O,O'-di(2-aminopropyl)polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol monomer. In the present application, the weight average molecular weight of the O,O'-di(2-aminopropyl)polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol monomer is preferably 500-1000, more preferably 500-900, and further preferably 500.

[0043] The present application uses an O,O'-di(2-aminopropyl)polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol monomer with a weight average molecular weight of 500-1000 as a chain extender, which can increase the molecular weight of the polymer of the heat-induced large-span reversible adhesive glue material, increase the flexibility of the polymer molecular chain, thereby improving the bonding strength of the heat-induced large-span reversible adhesive glue material and expanding the span of the reversible adhesive bonding strength.

[0044] The preparation raw material of the heat-induced large-span reversible adhesive glue material provided by the present application comprises a dopamine hydrochloride monomer.

[0045] The present application uses a dopamine hydrochloride monomer as a functional monomer for providing bonding strength, which contains a catechol structure that can interact with various materials to be bonded, giving the heat-induced large-span reversible adhesive glue material good interfacial adhesion performance. The amino structure contained in the dopamine hydrochloride monomer and the O,O'-di(2-aminopropyl)polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol monomer can undergo a Michael addition reaction with a pentaerythritol acrylate monomer and a disulfide urea-based olefin monomer.

[0046] The preparation raw material of the heat-induced large-span reversible adhesive glue material provided by the present application comprises a disulfide urea-based olefin monomer. In the present application, the disulfide urea-based olefin monomer preferably comprises one or more of the following structures:

[0047]

[0048] More preferably

[0049] The application also provides a preparation method of the disulfide bond urea-based olefin monomer, and the preparation steps include:

[0050] The disulfide diamine, isocyanate and solvent are mixed to perform an addition reaction to obtain the disulfide bond urea-based olefin monomer.

[0051] In the application, the disulfide diamine preferably includes 4,4'-dithiodianiline and / or cystamine monomer. In the application, the isocyanate preferably includes isocyanatoethyl methacrylate and / or 2-isocyanatoethyl acrylate. In the application, the solvent preferably includes acetone.

[0052] In the application, the ratio of the disulfide diamine, isocyanate and solvent is preferably 1 mmol: 2-2.2 mmol: 5-6 mL, and more preferably 1 mmol: 2-2.1 mmol: 5-5.5 mL.

[0053] In the application, the addition reaction is preferably performed in a nitrogen atmosphere. In the application, the temperature of the addition reaction is preferably 20-30℃, and more preferably 25℃. In the application, the time of the addition reaction is preferably 30-60 h, and more preferably 40 h.

[0054] After the addition reaction, the application preferably further includes sequentially removing the solvent, washing, suction filtering and drying the material liquid after the addition reaction. In the application, the method for removing the solvent preferably includes rotary evaporation. In the application, the reagent used for washing is preferably acetonitrile. The application does not limit the specific operation mode of the removal of the solvent, washing, suction filtering and drying, which can be performed according to the conventional operation in the art.

[0055] The application uses the disulfide bond urea-based olefin monomer as a reversible adhesion dynamic regulator, which is rich in hydrogen bonds and disulfide bonds. The two dynamic bonds can play a role in regulating the thermal induction of large-span reversible adhesion glue material polymer chain rupture and reconstruction, and are the key to realizing reversible adhesion. In the application, the disulfide bond urea-based olefin monomer contains urea groups, can form a large number of hydrogen bonds, increase the internal bonding strength of the polymer of the thermal induction of large-span reversible adhesion glue material, and further increase the bonding strength of the thermal induction of large-span reversible adhesion glue. Moreover, the disulfide bond and the hydrogen bond begin to break during heating, completely break and become liquid at a temperature above 100℃, and when the temperature decreases to room temperature, the disulfide bond and the hydrogen bond are reconstructed and recovered, realizing the reversible adhesion of the thermal induction of large-span reversible adhesion glue material, and maintaining a relatively high bonding strength after multiple heating and cooling cycles.

[0056] In the present application, the molar ratio of the pentaerythritol acrylate monomer, the O,O'-bis(2-aminopropyl)polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol monomer, the dopamine hydrochloride monomer and the disulfide urea olefin monomer is 1:(1-2):(1-3.5):(1-2), more preferably 1:(1.5-2):(3-3.5):(1.5-2). In the present application, the molar ratio of the acid binding agent to the dopamine hydrochloride monomer is (1-2):1, preferably (1.2-1.5):1.

[0057] The preparation raw material of the heat-induced large-span reversible adhesive glue material provided by the present application comprises an acid binding agent. In the present application, the acid binding agent is preferably an organic base type acid binding agent, and the organic base type acid binding agent is preferably triethylamine.

[0058] The organic base type acid binding agent in the present application has the effect of neutralizing dopamine hydrochloride, so that the reaction system can remain alkaline.

[0059] The preparation raw material of the heat-induced large-span reversible adhesive glue material provided by the present application comprises an organic solvent. In the present application, the organic solvent preferably comprises one or more of N,N-dimethylformamide, ethyl acetate, butyl acetate, acetone, butanone, cyclohexanone, tetrahydrofuran, ethylene glycol ethyl ether acetate, propylene glycol ethyl ether acetate and dimethyl sulfoxide, and more preferably dimethyl sulfoxide.

[0060] In the present application, the ratio of the total amount of all monomers in the preparation raw material of the heat-induced large-span reversible adhesive glue material to the amount of the organic solvent is preferably 1 g:3-3.5 g.

[0061] In the present application, dimethyl sulfoxide is preferably used as the solvent, which has good dispersion effect on the four monomers, i.e. the pentaerythritol acrylate monomer, the O,O'-bis(2-aminopropyl)polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol monomer, the dopamine hydrochloride monomer and the disulfide urea olefin monomer. The reactants are fully contacted and reacted, the viscosity of the reaction system is moderate, and the Michael addition reaction can be carried out normally.

[0062] The present application provides a preparation method of the heat-induced large-span reversible adhesive glue material, which comprises the following preparation steps:

[0063] The pentaerythritol acrylate monomer, the O,O'-bis(2-aminopropyl)polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol monomer, the dopamine hydrochloride monomer, the disulfide urea olefin monomer and the organic solvent are mixed and stirred to obtain a prepolymer mixture;

[0064] The prepolymer mixture is mixed with the acid binding agent to carry out Michael addition reaction, so as to obtain the heat-induced large-span reversible adhesive glue material.

[0065] The present application mixes and stirs a pentaerythritol acrylate monomer, an O,O'-bis(2-aminopropyl)polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol monomer, a dopamine hydrochloride monomer, a disulfide urea olefin monomer, and an organic solvent to obtain a prepolymer mixture.

[0066] In the present application, the mixing and stirring time is preferably 10-15 min, more preferably 10 min.

[0067] In the present application, the mixing method is not specifically limited, and the raw materials can be mixed uniformly.

[0068] After obtaining the prepolymer mixture, the present application mixes the prepolymer mixture with an acid-binding agent to perform a Michael addition reaction to obtain the heat-induced large-span reversible adhesive glue material.

[0069] In the present application, the Michael addition reaction is preferably performed in a three-necked flask. In the present application, the temperature of the Michael addition reaction is preferably 65-95℃, more preferably 80-85℃. In the present application, the time of the Michael addition reaction is preferably 3-6 h, more preferably 5-5.5 h. In the present application, the Michael addition reaction is preferably performed under the conditions of oil bath and light shielding.

[0070] In the present application, the specific reaction process and mechanism of the Michael addition reaction are that the amino groups carried in the O,O'-bis(2-aminopropyl)polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol monomer and the dopamine hydrochloride monomer undergo an addition reaction with the carbon-carbon double bonds carried in the pentaerythritol acrylate monomer and the disulfide urea olefin monomer under alkaline conditions. The present application has the advantage of simple reaction operation by using the Michael addition reaction.

[0071] After the Michael addition reaction, the present application preferably washes the liquid mixture product to obtain a solid glue, which is the heat-induced large-span reversible adhesive glue material. In the present application, the reagent used for the washing is preferably methyl tert-butyl ether, and the number of washing is preferably ≥4 times.

[0072] The present application provides the application of the heat-induced large-span reversible adhesive glue material in the bonding of plastics, glass, metal, and wood.

[0073] In the present application, the application preferably comprises the following steps:

[0074] The heat-induced large-span reversible adhesive glue material is heated to form a glue solution, which is coated on the surface of a substrate and solidified after lamination.

[0075] In the present application, the heating temperature is preferably ≥100℃, more preferably 100-110℃.

[0076] In the present application, the substrate preferably includes steel, titanium alloy, aluminum, glass, epoxy resin and wood.

[0077] In the present application, the curing temperature is preferably room temperature 25±5℃. In the present application, the curing time is preferably 10-20h, more preferably 12-20h.

[0078] The heat-induced large-span reversible adhesive material provided by the present application has high bonding strength, can be repeatedly bonded and dissociated, and has the advantages of convenient and fast operation.

[0079] The technical solutions of the present application will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only used to help understand the present application and should not be regarded as specific limitations on the present application.

[0080] Example 1

[0081] Preparation of disulfide bond urea-based olefin monomer A: 4,4'-dithiodianiline 1 mmol, isocyanatoethyl methacrylate monomer 2 mmol and acetone 5 mL were mixed and added to a three-necked flask, and an addition reaction was carried out under the condition of nitrogen flow, the temperature of the addition reaction was 25℃, and the reaction time was 40h. The liquid after the addition reaction was sequentially subjected to rotary evaporation, washed with acetonitrile for 3 times, and then filtered and dried to obtain a brown powder, which was disulfide bond urea-based olefin monomer A. The structural formula of the obtained disulfide bond urea-based olefin monomer A is shown as formula one:

[0082]

[0083] The disulfide bond urea-based olefin monomer A obtained by high performance liquid chromatography detection has a purity of 99%;

[0084] Figure 1 The nuclear magnetic resonance hydrogen spectrum of the disulfide bond urea-based olefin monomer A prepared in Example 1 is shown in Figure 1, Figure 2 The nuclear magnetic resonance carbon spectrum of the disulfide bond urea-based olefin monomer A prepared in Example 1 is shown in Figure 2, from Figure 1 and Figure 2 It can be seen that the disulfide bond urea-based olefin monomer A prepared in Example 1 has the same structure as formula one, contains disulfide bond and urea group structure, and has high purity without impurity peaks.

[0085] Pentaerythritol tetraacrylate 1.5 mmol, O,O'-bis(2-aminopropyl)polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol (weight average molecular weight 500) 3 mmol, dopamine hydrochloride 5.25 mmol, and the prepared disulfide bond urea-based olefin monomer A 3 mmol were dissolved in 15 g of dimethyl sulfoxide and stirred to obtain a prepolymer mixture.

[0086] The obtained prepolymer mixture was added to a reaction bottle, stirred and dissolved uniformly, 7.2 mmol of triethylamine was added, the reaction bottle was placed in an 80°C oil bath, and the Michael addition reaction was carried out in the dark for 5 h. After the reaction was completed, a liquid mixture was obtained. The obtained liquid mixture was washed with methyl tert-butyl ether 5 times to obtain a solid adhesive, which was a thermally induced large-span reversible adhesive material.

[0087] Figure 3 The nuclear magnetic resonance spectrum of the thermally induced large-span reversible adhesive material prepared in Example 1 was obtained, and the shifts of various functional groups were assigned in Figure 3 , Figure 3 14 and 17 in the above table are urea hydrogen, 15 is catechol hydrogen, and the disulfide bond does not contain hydrogen, so it is not shown in the nuclear magnetic resonance spectrum. The large-span reversible adhesive material prepared in Example 1 contains catechol, disulfide bond and urea functional groups, which can realize high-strength bonding between the adhesive material and the adherend, and quickly switch the adhesion strength by temperature.

[0088] Figure 4 The Raman spectrum of the thermally induced large-span reversible adhesive material prepared in Example 1 was obtained, and it can be seen from Figure 4 that a characteristic peak of the disulfide bond is shown at 491 cm -1 .

[0089] The obtained thermally induced large-span reversible adhesive material was heated to 100°C to form a paste-like adhesive liquid. The obtained paste-like adhesive liquid was directly coated on the surface of a steel sheet with a coating area of 12.5 mm*25 mm, and was placed at room temperature for 12 h for curing to realize bonding and obtain a bonded sample.

[0090] Figure 5 The bonding strength test schematic diagram of the thermally induced large-span reversible adhesive material prepared in Example 1 was obtained. According to the standard ASTM D1002-10, a universal tensile testing machine was used to test the bonding strength of the bonded sample, the tensile speed was set to 20 mm / min, and the test counterpart used was a steel sheet. The bonding strength of the thermally induced large-span reversible adhesive material prepared in Example 1 on the surface of the steel sheet was 6.45 MPa.

[0091] The performance of the thermally induced large-span reversible adhesive material prepared in Example 1 was detected after 100 cycles of repeated adhesion. The obtained thermally induced large-span reversible adhesive material was coated on a steel sheet, and after being placed at room temperature for 12 h for curing, a universal tensile testing machine was used to detect the bonding strength with a tensile speed of 20 mm / min. After each tensile test, two steel sheets were heated at 100°C until the reversible adhesive material melted, and then the two steel sheets were again pasted and placed at room temperature for 12 h for curing, and the bonding strength test was again performed. The detection resultsFigure 6 As shown, Figure 6 The bonding strength diagram of the heat-induced large-span reversible adhesive glue prepared in Example 1 after 100 times of repeated cycle adhesion is shown in the figure from Figure 6 It can be seen that the bonding strength after 100 times of repeated cycle adhesion still reaches 4.0 MPa, which indicates that the heat-induced large-span reversible adhesive glue obtained by the present application has stable reversible adhesion and high bonding strength.

[0092] The switching time of reversible adhesion and the bonding strength at the switching time of reversible adhesion are detected at the same time as the detection of the performance of the heat-induced large-span reversible adhesive glue after 100 times of repeated cycle adhesion. The steel sheet is heated to the melting point of the adhesive glue at 100℃, and the time from the start of heating to the separation of the reversible adhesive glue from the molten steel sheet is the switching time of reversible adhesion. The switching time of reversible adhesion is recorded by using an automatic timer. The bonding strength at the time of reversible adhesion glue melting and separating from the steel sheet is the bonding strength at the switching time of reversible adhesion. The detection results are as follows: the switching time of reversible adhesion of the heat-induced large-span reversible adhesive glue prepared in Example 1 is 30s, and the bonding strength at the switching time of reversible adhesion is 0.04 MPa. The detection results show that the switching time of reversible adhesion of the heat-induced large-span reversible adhesive glue prepared by the present application is short, easy to perform multiple repeated bonding, and the bonding strength at the switching time of reversible adhesion still reaches 0.04 MPa, so that the substrate will not easily fall off, which is beneficial to operation and very convenient to use.

[0093] Example 2

[0094] The only difference from Example 1 is that the bonded substrate is a titanium sheet.

[0095] The detection results are as follows: the bonding strength is 6.10 MPa, the switching time of reversible adhesion is 30s, and the bonding strength at the switching time of reversible adhesion is 0.02 MPa.

[0096] Example 3

[0097] The only difference from Example 1 is that the bonded substrate is an aluminum sheet.

[0098] The detection results are as follows: the bonding strength is 4.98 MPa, the switching time of reversible adhesion is 30s, and the bonding strength at the switching time of reversible adhesion is 0.05 MPa.

[0099] Example 4

[0100] The only difference from Example 1 is that the bonded substrate is glass.

[0101] The detection results are as follows: the bonding strength is 3.94 MPa, the switching time of reversible adhesion is 30s, and the bonding strength at the switching time of reversible adhesion is 0.01 MPa.

[0102] Example 5

[0103] The only difference from Example 1 is that the adherend is a sheet made of epoxy resin.

[0104] The test results are that the adhesive strength is 2.62 MPa, the switching time of reversible adhesion is 30 s, and the adhesive strength at the switching of reversible adhesion is 0.01 MPa.

[0105] Example 6

[0106] The only difference from Example 1 is that the adherend is a wood sheet.

[0107] The test results are that the adhesive strength is 2.46 MPa, the switching time of reversible adhesion is 30 s, and the adhesive strength at the switching of reversible adhesion is 0.02 MPa.

[0108] Example 7

[0109] The difference from Example 1 is that the "isocyanatoethyl methacrylate monomer" is replaced by "2-isocyanatoethyl acrylate monomer", and the obtained is disulfide bond ureido olefin monomer B, the structural formula is shown in Formula II:

[0110]

[0111] The disulfide bond ureido olefin monomer B obtained by high performance liquid chromatography detection has a purity of 98.9%.

[0112] Example 8

[0113] The difference from Example 1 is that the "4,4'-dithiodianiline monomer" is replaced by "cystamine monomer", and the obtained is disulfide bond ureido olefin monomer C, the structural formula is shown in Formula III:

[0114]

[0115] The disulfide bond ureido olefin monomer C obtained by high performance liquid chromatography detection has a purity of 99.2%.

[0116] Example 9

[0117] The difference from Example 1 is that the "isocyanatoethyl methacrylate monomer" is replaced by "2-isocyanatoethyl acrylate monomer", and the "4,4'-dithiodianiline monomer" is replaced by "cystamine monomer", and the obtained is disulfide bond ureido olefin monomer D, the structural formula is shown in Formula IV:

[0118]

[0119] The disulfide bond ureido olefin monomer D obtained by high performance liquid chromatography detection has a purity of 99.3%.

[0120] Comparative Example 1

[0121] The difference from Example 1 is that urea-based olefin monomer is used to replace the disulfide bond urea-based olefin monomer A in Example 1. The urea-based olefin monomer used in Comparative Example 1 has no disulfide bond, and its structural formula is shown as Formula V:

[0122]

[0123] The adhesive glue obtained in Comparative Example 1 is detected, and the detection result is that the bonding strength is 5.53 MPa, and the performance of the adhesive glue in repeated cycle adhesion for 100 times is that the switching time of reversible adhesion is 55 s, the bonding strength in reversible adhesion switching is 0 MPa, and the steel sheet falls off. The detection result shows that the bonding strength of the adhesive glue obtained in Comparative Example 1 is lower than that of the heat-induced large-span reversible adhesive material obtained in Example 1, the switching time of reversible adhesion is long, and it is indicated that without the reconstruction adjustment of disulfide bond, the adhesive glue is difficult to realize reversible adhesion faster, and also cannot maintain a high bonding strength in repeated cycle adhesion.

[0124] The above only describes the preferred embodiments of the present application, and does not limit the present application in any form. It should be noted that for ordinary skilled persons in the art, some improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A thermally induced, large-span reversible adhesive material, characterized in that, The following raw materials are included in the preparation: Pentaerythritol acrylate monomers, O,O'-di(2-aminopropyl)polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol monomers, dopamine hydrochloride monomers, disulfide bonded ureyl olefin monomers, acid-binding agents and organic solvents; The thermally induced, large-span reversible adhesive material includes disulfide bonds, urea groups, and catechol structures; The disulfide-bonded ureyl olefin monomer includes one or more of the following structures: ； The molar ratio of the pentaerythritol acrylate monomer, O,O'-di(2-aminopropyl)polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol monomer, dopamine hydrochloride monomer, and dithiobonded urea olefin monomer is 1:(1~2):(1~3.5):(1~2). The molar ratio of the acid-binding agent to the dopamine hydrochloride monomer is (1~2):

1.

2. The thermally induced large-span reversible adhesive material according to claim 1, characterized in that, The pentaerythritol acrylate monomers include one or more of pentaerythritol tetraacrylate, pentaerythritol triacrylate, and polydipentaerythritol hexaacrylate.

3. The thermally induced, large-span reversible adhesive material according to claim 1, characterized in that, The weight-average molecular weight of the O,O'-bis(2-aminopropyl)polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol monomer is 500~1000.

4. The thermally induced large-span reversible adhesive material according to claim 1, characterized in that, The acid-binding agent is an organic base acid-binding agent; The organic base acid-binding agent is triethylamine; The organic solvent includes one or more of N,N-dimethylformamide, ethyl acetate, butyl acetate, acetone, butanone, cyclohexanone, tetrahydrofuran, ethylene glycol ethyl ether acetate, propylene glycol ethyl ether acetate, and dimethyl sulfoxide.

5. The method for preparing the thermally induced large-span reversible adhesive material according to any one of claims 1 to 4, characterized in that, The preparation steps include the following: Pentaerythritol acrylate monomers, O,O'-di(2-aminopropyl)polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol monomers, dopamine hydrochloride monomers, disulfide bonded ureyl olefin monomers and organic solvents were mixed and stirred to obtain a prepolymer mixture; The prepolymer mixture is mixed with an acid-binding agent and subjected to a Michael addition reaction to obtain the thermally induced large-span reversible adhesive material.

6. The preparation method according to claim 5, characterized in that, The Michael addition reaction is carried out at a temperature of 65-95°C for 3-6 hours.

7. The application of the thermally induced large-span reversible adhesive material according to any one of claims 1 to 4 or the thermally induced large-span reversible adhesive material prepared by the preparation method according to any one of claims 5 to 6 in the bonding of plastics, glass, metals and wood.

8. The application according to claim 7, characterized in that, The specific application method includes the following steps: The thermally induced large-span reversible adhesive material is heated to form an adhesive liquid, which is then coated onto the surface of the substrate and cured after bonding. The heating temperature is ≥100℃; The curing temperature is room temperature (25±5℃), and the curing time is 10~20h.

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