Electrically detachable single-component polyurethane hot melt adhesive as well as preparation method and application thereof

Abstract

The invention belongs to the field of adhesives, and particularly relates to an electrically detachable single-component polyurethane hot melt adhesive as well as a preparation method and application thereof. The viscosity range of the electrically detachable single-component reactive polyurethane hot melt adhesive at 25 DEG C is 1000-150000cps, the attenuation rate of the bonding strength after the electrically detachable single-component reactive polyurethane hot melt adhesive is electrified at the voltage of 1-100V is more than 80%, and the content of isocyanate groups in the electrically detachable single-component reactive polyurethane hot melt adhesive is 5-20%. The polyurethane hot melt adhesive provided by the invention is low in melt viscosity, can be dispensed at room temperature, is high in final bonding strength, has a detachable function under a power-on condition, and has a wide practical application prospect.

Description

Technical Field

[0001] The invention belongs to the field of adhesives, and in particular relates to an electrically detachable single-component polyurethane hot melt adhesive and a preparation method and application thereof. Background Art

[0002] Reactive polyurethane hot melt adhesive is often used to bond and fix electronic product components in electronic products such as smartphones, tablets, smart watches, and TWS headsets. Electronic product components bonded with reactive polyurethane hot melt adhesives are often of high value. When poor assembly, after-sales product repairs, or recycling of valuable electronic product components occur, it is usually necessary to disassemble some of the bonded components. Therefore, the adhesive is usually required to have excellent bonding reliability while being easy to disassemble under certain conditions.

[0003] Reactive polyurethane hot melt adhesive is mainly composed of isocyanate-terminated oligomers. The isocyanate groups in the isocyanate-terminated oligomers can react with moisture in the air and form a cross-linked chemical structure after complete curing, thereby achieving high bonding strength. However, the covalent bonds obtained by the reaction of isocyanate groups with moisture are irreversible, and the cross-linked structure is difficult to destroy. It is usually difficult to disassemble the adhesive after complete curing. If the bonded materials need to be separated, it is often necessary to use large external forces, high temperatures, chemical reagents and other conditions, and the bonded materials may be damaged during the disassembly of the adhesive, resulting in large economic losses.

[0004] In recent years, there are also technologies that add alkali metal salts and solvated matrices to polyurethane hot melt adhesives to give polyurethane hot melt adhesives the function of being disassembled under power-on conditions. However, although the existing electrically disassembled polyurethane hot melt adhesives have the function of being disassembled under power-on conditions, due to the high melt viscosity of such polyurethane hot melt adhesives, they are a solid substance at room temperature and usually need to be heated to a melting temperature (usually 90°C to 160°C) or above before they can be extruded and glued. At this time, it is generally necessary to equip and use professional heating glue-applying equipment, but this will greatly limit the application scenarios of such single-component polyurethane hot melt adhesives while increasing the cost of glue. For example, it is inconvenient to use such polyurethane hot melt adhesives in places such as homes and repair markets where it is inconvenient to equip heating equipment, thereby greatly limiting the wide application and promotion of such single-component polyurethane hot melt adhesives. Furthermore, the existing electrically disassembled polyurethane hot melt adhesives have the defect of low final bonding strength. Although they have certain electrically disassembled functions, their final bonding strength is low and their reliability is poor. There is a large performance gap with traditional reactive polyurethane hot melt adhesives, and it is difficult to meet the performance requirements of actual application scenarios.

[0005] In summary, there is an urgent need to develop an adhesive with low melt viscosity, which can be dispensed at room temperature, has high final bonding strength and can be electrically disassembled to meet the application needs of the market. Summary of the invention

[0006] The first object of the present invention is to provide an electrically disassembled one-component polyurethane hot melt adhesive with low melt viscosity, dispensing capability at room temperature and high final bonding strength.

[0007] The second object of the present invention is to provide a method for preparing the electrically decomposable one-component polyurethane hot melt adhesive.

[0008] The third object of the present invention is to provide an application of the above-mentioned electrically disassembled single-component polyurethane hot melt adhesive in products with adhesive removal requirements.

[0009] Specifically, the electrically detachable one-component reactive polyurethane hot melt adhesive provided by the present invention has a viscosity range of 1000 to 150000 cps at 25°C and a bonding strength attenuation rate of more than 80% after power is applied at a voltage of 1 to 100V. The content of isocyanate groups in the electrically detachable one-component reactive polyurethane hot melt adhesive is 5 to 20%.

[0010] In a preferred embodiment, the raw materials for preparing the electrically detachable one-component reactive polyurethane hot melt adhesive contain polyisocyanate compounds, low-viscosity polyol compounds, ionic liquids, and optional rheology modifiers, silane coupling agents, water absorbents, and catalysts. The molar equivalent ratio of isocyanate groups in the polyisocyanate compounds to hydroxyl groups in the low-viscosity polyol compounds is (5-10):1, and the glass transition temperature of the low-viscosity polyol compounds is below 0°C and the melting point is below 40°C.

[0011] The preparation method of the electrically detachable one-component reactive polyurethane hot melt adhesive provided by the present invention comprises uniformly mixing a polyisocyanate compound, a low-viscosity polyol compound, an ionic liquid, and an optional rheology modifier, a silane coupling agent, a water absorbent and a catalyst to obtain the electrically detachable one-component reactive polyurethane hot melt adhesive.

[0012] After in-depth and extensive research, the inventors of the present invention have found that the polyurethane polymer with isocyanate functional groups used in the existing electrically disassembled polyurethane hot melt adhesive is a polyurethane prepolymer obtained by reacting a polyol compound with an excess of polyisocyanate compounds. The molar equivalent ratio of isocyanate groups in such polyisocyanate compounds to hydroxyl groups in polyol compounds is usually set at (1.5-2.5):1 (i.e., the molar ratio of NCO / OH is (1.5-2.5):1). The polyurethane prepolymer prepared according to this stoichiometric relationship has a low isocyanate content, a large molecular weight, and a large interaction force between molecular chains, resulting in the final polyurethane prepolymer having a high melt viscosity and being difficult to dispense at room temperature. In addition, some polyol compounds used in such polyurethane prepolymers with isocyanate functional groups have strong crystallinity or a high glass transition temperature (Tg) at room temperature, and the polyurethane prepolymer prepared by reacting room temperature crystalline polyols or high Tg polyols with isocyanate compounds is usually a solid substance at room temperature. Therefore, the electrically degradable polyurethane hot melt adhesive currently prepared by traditional methods is usually a solid substance at room temperature and needs to be heated to above the melting point (90°C to 160°C) before it can be melted and applied. This greatly increases the threshold for using such polyurethane hot melt adhesives, increases the cost of adhesive equipment, and also increases the risk of operators being burned during the adhesive application process.

[0013] The existing electrically disassembled polyurethane hot melt adhesive is to add ionic liquid or alkali metal salt and solvated matrix to the polyurethane hot melt adhesive, and utilize the Faraday reaction of anions and cations in the ionic liquid or alkali metal salt under the condition of power on, so as to give the polyurethane hot melt adhesive the function of disassembly under the condition of power on. Among them, although the liquid substances such as ionic liquid and solvated matrix introduced into the polyurethane hot melt adhesive are conducive to realizing the function of electrical disassembly, such liquid substances cannot participate in the curing of the polyurethane hot melt adhesive, and still exist in the state of initial low viscosity after the polyurethane hot melt adhesive is cured, so it has a certain negative effect on the final bonding strength of the adhesive. In addition, since the equivalent ratio of isocyanate to hydroxyl in the current isocyanate-terminated polyurethane prepolymer is relatively low (the equivalent ratio of NCO / OH is between 1.5 and 2.5), the isocyanate content of the polyurethane prepolymer finally obtained is low, so the crosslinking density of such polyurethane prepolymer after the final wet curing is low, so that the adhesive itself has a low bonding strength after curing, and the bonding strength will be further reduced after being negatively affected by the liquid components such as ionic liquid and solvated matrix. Therefore, although the electrically disassembled polyurethane hot melt adhesive can be prepared by adding ionic liquid or alkali metal salt in combination with a solvating matrix to the polyurethane hot melt adhesive, its final adhesion still has great deficiencies, which is not conducive to the application and promotion of such products.

[0014] The key to the invention is to break the design limitation of setting the equivalent ratio of isocyanate to hydroxyl between (1.5-2.5):1 in the traditional electrically detachable polyurethane hot melt adhesive preparation process, and innovatively set the equivalent ratio of isocyanate group to hydroxyl group within the range of (5-10):1 to control the content of isocyanate group in the electrically detachable single-component reactive polyurethane hot melt adhesive within 5-20%, and at the same time, a polyol compound with low crystallinity and low glass transition temperature at room temperature is selected to react with a large excess of isocyanate compounds to prepare a polyurethane hot melt adhesive that is liquid at room temperature. The hot melt adhesive has a high isocyanate group content, and the finally prepared polyurethane prepolymer has a low molecular weight, a small interaction force between molecular chains, and a low melt viscosity. At the same time, more isocyanate monomers can dilute the melt viscosity of the polyurethane prepolymer on the one hand, and on the other hand, the isocyanate group content is high, and the cross-linking density after final curing is high, so that a higher bonding strength can be formed. At the same time, the present invention innovatively introduces ionic liquids into this liquid polyurethane hot melt adhesive, and uses the Faraday reaction that can occur in the ionic liquid after power is applied to give this type of liquid polyurethane hot melt adhesive a certain electrical disassembly performance. In addition, the ionic liquid selected by the present invention is a liquid substance at room temperature, which can be directly added to the polyurethane hot melt adhesive system very conveniently, thereby effectively avoiding the introduction of a solvated matrix into the adhesive system, and effectively reducing the negative impact of the solvated matrix on the bonding strength of the polyurethane hot melt adhesive. At the same time, the ionic liquid introduced into the low-viscosity polyurethane hot melt adhesive can also effectively reduce the viscosity of the polyurethane hot melt adhesive. Furthermore, as mentioned above, the present invention can make the isocyanate group in the system more excessive by increasing the equivalent ratio of isocyanate group to hydroxyl group, and the cross-linking density is high after curing, and even if it is affected by the uncured ionic liquid, it can still maintain a relatively high bonding strength. Therefore, the ionic liquid introduced in the present invention can give the polyurethane hot melt adhesive the function of being disassembled under power-on conditions on the one hand, and the ionic liquid introduced on the other hand can also significantly reduce the melt viscosity of the polyurethane hot melt adhesive, so that the polyurethane hot melt adhesive of the present invention can be directly glued at room temperature, which greatly reduces the threshold for applying such polyurethane hot melt adhesives that can be disassembled by power on, reduces the equipment cost required for applying polyurethane hot melt adhesives, and effectively avoids the risk of operators being scalded during the glue application process. In addition, the polyurethane hot melt adhesive of the present invention has the function of being electrically disassembled after curing, and at the same time, it also has a high bonding strength before power is not turned on, providing sufficiently excellent reliability for the product. In summary, the polyurethane hot melt adhesive provided by the present invention has a low melt viscosity, can be dispensed at room temperature, has a high final bonding strength, and has a disassembly function under power-on conditions, and has broad practical application prospects. DETAILED DESCRIPTION

[0015] The electrically detachable one-component reactive polyurethane hot melt adhesive provided by the present invention has a viscosity range of 1000 to 150000 cps at 25° C., specifically 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, 10000, 30000, 50000, 70000, 90000, 110000, 130000, 150000 cps or any value therebetween.

[0016] The electrically detachable single-component reactive polyurethane hot melt adhesive provided by the present invention has a bonding strength attenuation rate of more than 80% after being energized at a voltage of 1 to 100 V, and can specifically be 80%, 82%, 85%, 88%, 90%, 92%, 95%, 98%, 99%, 100% or any value therebetween. The voltage required for the electrically detachable one-component reactive polyurethane hot melt adhesive to be electrically disassembled is preferably 1 to 100 V, and can specifically be 1 V, 3 V, 5 V, 7 V, 9 V, 10 V, 20 V, 30 V, 40 V, 50 V, 60 V, 70 V, 80 V, 90 V, 100 V or any value therebetween; the time required for electrical disassembly is preferably 1 s to 60 min, such as 1 s, 2 s, 15 s, 30 s, 40 s, 50 s, 1 min, 5 min, 10 min, 15 min, 20 min, 30 min, 40 min, 50 min, 60 min or any value therebetween.

[0017] The content of isocyanate groups in the electrically detachable one-component reactive polyurethane hot melt adhesive provided by the present invention is 5-20%, specifically 5%, 8%, 10%, 12%, 15%, 17%, 19%, 20% or any value therebetween. In the present invention, the content of isocyanate groups refers to the ratio of the total weight of all unreacted isocyanate functional groups in the system to the total weight of the polyurethane hot melt adhesive.

[0018] The electrically detachable single-component reactive polyurethane hot melt adhesive provided by the present invention is a liquid or paste at room temperature, and has the characteristics of low melt viscosity, room temperature dispensing, high final bonding strength and electrical disassembly.

[0019] In a preferred embodiment, the raw materials for preparing the electrically detachable one-component reactive polyurethane hot melt adhesive contain polyisocyanate compounds, low-viscosity polyol compounds, ionic liquids, and optional rheology modifiers, silane coupling agents, water absorbents, and catalysts. The molar equivalent ratio of isocyanate groups in the polyisocyanate compounds to hydroxyl groups in the low-viscosity polyol compounds is (5-10):1, and the glass transition temperature of the low-viscosity polyol compounds is below 0°C and the melting point is below 40°C. Among them, the molar equivalent ratio of isocyanate groups in the polyisocyanate compounds to hydroxyl groups in the low-viscosity polyol compounds can be specifically 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, or any value therebetween. The glass transition temperature of the low-viscosity polyol compound can be specifically 0°C, -2°C, -4°C, -6°C, -8°C, -10°C, -12°C, -14°C, -16°C, -18°C, -20°C, -22°C, -24°C, -26°C, -28°C, -30°C, -32°C, -34°C, -36°C, -38°C, -40°C, etc. The melting point of the low-viscosity polyol compound can be specifically 40°C, 38°C, 36°C, 34°C, 32°C, 30°C, 28°C, 26°C, 24°C, 22°C, 20°C, 18°C, 16°C, 14°C, 12°C, 10°C, 8°C, 6°C, 4°C, 2°C, 0°C, -5°C, -10°C, -15°C, -20°C, -30°C, etc.

[0020] In the present invention, the mass ratio of the total content of the polyisocyanate compound and the low-viscosity polyol compound to the content of the ionic liquid is preferably (5-46):1, specifically 5:1, 8:1, 15:1, 20:1, 25:1, 30:1, 35:1, 40:1, 43:1, 46:1 or any value therebetween. The mass ratio of the rheology modifier to the ionic liquid is preferably (0-5):1, specifically 0, 0.1:1, 0.5:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1 or any value therebetween. The mass ratio of the silane coupling agent to the ionic liquid is preferably (0-2.5):1, specifically 0, 0.005:1, 0.01:1, 0.05:1, 0.1:1, 0.3:1, 0.5:1, 0.8:1, 1:1, 1.2:1, 1.5:1, 1.8:1, 2:1, 2.2:1, 2.5:1 or any value therebetween. The mass ratio of the content of the water absorbent and the catalyst to the content of the ionic liquid is preferably independently (0-1):1, specifically 0, 0.005:1, 0.01:1, 0.05:1, 0.1:1, 0.3:1, 0.5:1, 0.8:1, 1:1 or any value therebetween.

[0021] In a preferred embodiment, based on the total weight of the raw materials for preparing the electrically detachable one-component reactive polyurethane hot melt adhesive, the total content of the polyisocyanate compound and the low-viscosity polyol compound is 75-92%, such as 75%, 78%, 80%, 82%, 85%, 88%, 90%, 92% or any value therebetween; the content of the ionic liquid is 2-15%, such as 2%, 5%, 8%, 10%, 12%, 15% or any value therebetween; the content of the rheology modifier is 2-10%, such as 2%, 5%, 8%, 10%, 12%, 15% or any value therebetween. 0% or any value therebetween; the content of the silane coupling agent is 0.1-5%, such as 0.1%, 0.5%, 0.8%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5% or any value therebetween; the content of the water absorbent is 0.1-2%, such as 0.1%, 0.5%, 0.8%, 1%, 1.5%, 2% or any value therebetween; the content of the catalyst is 0.1-2%, such as 0.1%, 0.5%, 0.8%, 1%, 1.5%, 2% or any value therebetween.

[0022] In the present invention, the polyisocyanate compound is a compound with two or more isocyanate groups at the terminal of the molecular chain, and can be specifically an aromatic isocyanate and / or an aliphatic isocyanate, and specific examples thereof include but are not limited to at least one of isophorone diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, diphenylmethane-4,4'-diisocyanate, diphenylmethane-2,4'-diisocyanate, hydrogenated xylene diisocyanate, 1,5-naphthalene diisocyanate, 1,5-pentane diisocyanate, 1,4-phenylene diisocyanate, xylene diisocyanate, tetramethylxylene diisocyanate, norbornane diisocyanate, lysine diisocyanate, triphenylmethane triisocyanate, thiophosphoric acid triphenyl isocyanate and 1,6,11-undecane triisocyanate.

[0023] In the present invention, the number average molecular weight of the low viscosity polyol compound is preferably 400-6000 g / mol, such as 400, 500, 800, 1000, 1200, 1500, 1800, 2000, 2500, 3000, 3500, 4000, 4500, 5000, 5500, 6000 g / mol or any value therebetween. The low viscosity polyol compound can be any existing polyol compound having a glass transition temperature of 0°C or less and a melting point of 40°C or less, and specific examples thereof include but are not limited to at least one of liquid polyester polyol, liquid polyether polyol, liquid polycarbonate polyol, liquid polycaprolactone polyol, fatty acid dimer diol, castor oil derivative polyol and hydroxy-terminated polybutadiene polyol.

[0024] In the present invention, the melting point of the ionic liquid is preferably below 25°C, such as 25°C, 23°C, 20°C, 18°C, 15°C, 13°C, 10°C, 8°C, 5°C, 2°C, 0°C, -5°C, -10°C, -15°C, -20°C, -30°C, -40°C, etc. The ionic liquid is composed of cations and anions. The cations are preferably selected from at least one of imidazole cations, pyrrole cations, quaternary ammonium salt cations, quaternary phosphonium salt cations, pyrrolidine cations and piperidine cations. The anions are preferably selected from at least one of trifluoromethanesulfonate anions, tetrafluoroborate anions, hexafluorophosphate anions, bisfluoromethanesulfonyl imide anions, hydrogen sulfate anions, ethyl sulfate anions and p-toluenesulfonate anions. Specific examples of the above-mentioned ionic liquids include, but are not limited to: 1-butyl-3-methylimidazolium trifluoromethanesulfonate, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-ethyl-2,3-dimethylimidazolium trifluoromethanesulfonate, 1-octyl-3-methylimidazolium trifluoromethanesulfonate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-propyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-2,3-dimethylimidazolium tetrafluoroborate, 1-propyl-2,3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium ethyl sulfate, 1-ethyl-2,3-dimethylimidazolium ethyl sulfate, 1-butyl-3-methylimidazolium bis(trifluoromethane) at least one of bis(trifluoromethanesulfonyl)imide salts, 1,3-diethylimidazolium bis(trifluoromethanesulfonyl)imide salts, 1-propyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salts, 1-hexyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salts, 1,2-dimethyl-3-propylimidazolium bis(trifluoromethanesulfonyl)imide salts, 1-ethyl-2,3-dimethylimidazolium bis(trifluoromethanesulfonyl)imide salts, N-butylpyridinium tetrafluoroborate, hexyltriethylammonium bis(trifluoromethanesulfonyl)imide salts, methyltrioctylphosphonium bis(trifluoromethanesulfonyl)imide salts, N-butyl-N-methylpyrrolidine bis(trifluoromethanesulfonyl)imide salts, N-butyl-N-methylpyrrolidine trifluoromethanesulfonate salts and N-propyl-N-methylpiperidinium bis(trifluoromethanesulfonyl)imide salts.

[0025] In the present invention, the rheology modifier is preferably fumed silica, and specific examples thereof include but are not limited to at least one of AEROSIL A150, AEROSIL A200, AEROSIL A300, AEROSIL A380, AEROSIL R972, AEROSIL R974, AEROSIL R202, AEROSIL R812, HDK V15, HDK N20, HDK T30, HDK T40, HDK H13L, HDK H15, HDK H15L, HDK H16, HDK H17, HDK H18, HDK H2000, HDK H20, HDK H21, HDK H30, HDK H30RM, LM-150, M-5, E-5, EH-5, TS610, TS620, TS622, TS720, TS530 and TSUBOND. The specific surface area of ​​the fumed silica is preferably 90 to 380 m 2 / g, specifically 90, 100, 120, 150, 180, 200, 220, 240, 260, 280, 300, 320, 340, 360, 380 m 2 / g or any value in between.

[0026] In the present invention, specific examples of the silane coupling agent include, but are not limited to: 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropylmethyldiethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, At least one of 3-(2-aminoethyl)aminopropyltrimethoxysilane, 3-(2-aminoethyl)aminopropyltriethoxysilane, 3-(2-aminoethyl)aminopropylmethyldimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 3-(meth)acryloxypropylmethyldimethoxysilane, 3-(meth)acryloxypropylmethyldiethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane and 3-isocyanatepropyltrimethoxysilane.

[0027] In the present invention, the water absorbent may be selected from at least one of a molecular sieve desiccant, an oxazolidine dehydrating agent, p-toluenesulfonyl isocyanate and triethyl orthoformate.

[0028] In the present invention, the catalyst can be selected from at least one of dibutyltin dilaurate, stannous octoate, zinc isooctanoate, bismuth isooctanoate, triethylamine, diethylenetriamine, triethylenediamine, N-ethylmorpholine and 2,2-dimorpholinyl diethyl ether.

[0029] The preparation method of the electrically detachable one-component reactive polyurethane hot melt adhesive provided by the present invention comprises uniformly mixing a polyisocyanate compound, a low-viscosity polyol compound, an ionic liquid, and an optional rheology modifier, a silane coupling agent, a water absorbent, and a catalyst to obtain an electrically detachable one-component reactive polyurethane hot melt adhesive. The mixing method is not particularly limited, and preferably comprises the following steps: S1, dehydrating the low-viscosity polyol compound, the ionic liquid, the rheology modifier, the silane coupling agent, and the water absorbent to obtain a pretreated product; S2, stirring the pretreated product, the polyisocyanate compound, and the catalyst at 70 to 90° C. for 1 to 5 hours to obtain a one-component reactive polyurethane hot melt adhesive.

[0030] In the present invention, in step S1, the conditions for the dehydration treatment preferably include a temperature of 100-120°C, such as 100°C, 102°C, 104°C, 106°C, 108°C, 110°C, 112°C, 114°C, 116°C, 118°C, 120°C or any value therebetween; a rotation speed of 100-200r / min, such as 100r / min, 110r / min, 120r / min, 130r / min, 140r / min, 150r / min, 160r / min, 170r / min, 180r / min, 190r / min, 200r / min or any value therebetween; and a time of 1-5h, such as 1h, 2h, 3h, 4h, 5h or any value therebetween.

[0031] The present invention also provides application of the electrically detachable single-component reactive polyurethane hot melt adhesive in bonding electronic products.

[0032] The bonding substrate used in the electrically detachable single-component reactive polyurethane hot melt adhesive provided by the present invention is a substrate with electrical conductivity.

[0033] The present invention will be described in detail below by way of examples. The examples of the embodiments are intended to explain the present invention and should not be construed as limiting the present invention. If no specific techniques or conditions are specified in the embodiments, the techniques or conditions described in the literature in this area or the product instructions are used. If no manufacturer is specified for the reagents or instruments used, they are all conventional products that can be obtained commercially.

[0034] Example 1

[0035] By weight, 18.37 g (6.124 mmol) of a liquid polycarbonate diol with a number average molecular weight of 3000 (Kuraraypolyol C3090; Tg = -42°C; melting point <25°C), 21.43 g (6.124 mmol) of a liquid polyester diol with a number average molecular weight of 3500 (Dynacoll 7230; Tg = -30°C; melting point <25°C), 12.25 g (6.124 mmol) of a liquid polyester diol with a number average molecular weight of 2000 (stepanpol PH-56; Tg = -15°C; melting point <25°C), 7.00 g of 1-ethyl-3-methylimidazolium tetrafluoroborate (melting point = 15°C), 5.0 g of fumed silica HDK H20, 1.0 g of 3-mercaptopropyltrimethoxysilane and 0.2 g of a water absorbent Additive TI, heated to 110°C, vacuum dehydrated for 2h under stirring conditions of 150r / min, then cooled to 80°C, 34.45g (137.786mmol) of diphenylmethane-4,4'-diisocyanate (MDI) and 0.3g of stannous octoate were added, reacted for 2h under stirring conditions of 150r / min, and then discharged to obtain an electrically detachable one-component reactive polyurethane hot melt adhesive, which was vacuum sealed for storage. The content of isocyanate groups in the electrically detachable one-component reactive polyurethane hot melt adhesive is 10.03%.

[0036] Example 2

[0037] By weight, 40.30 g (13.43 mmol) of a liquid polyether diol with a number average molecular weight of 3000 (Dow Voranol WD2130; Tg<0°C; melting point<25°C), 8.96 g (4.478 mmol) of a polycaprolactone diol with a number average molecular weight of 2000 (PERSTORP CAPA 7201A; Tg<0°C; melting point=30-35°C), 12.0 g of 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (melting point=-12°C), 6.50 g of fumed silica AEROSIL R972, 0.3 g of 3-glycidoxypropyltrimethoxysilane and 0.5 g of a water absorbent Additive OF, heated to 110°C, vacuum dehydrated for 2h under stirring conditions of 150r / min, then cooled to 80°C, 31.34g (125.378mmol) of diphenylmethane-4,4'-diisocyanate (MDI) and 0.1g of 2,2-dimorpholinyl diethyl ether were added, reacted for 2h under stirring conditions of 150r / min, and then discharged to obtain an electrically detachable one-component reactive polyurethane hot melt adhesive, which was vacuum sealed for storage. The content of isocyanate groups in the electrically detachable one-component reactive polyurethane hot melt adhesive is 9.03%.

[0038] Example 3

[0039] By weight, 22.06 g (22.06 mmol) of a liquid polyester diol with a number average molecular weight of 1000 (Stepanpol PD-110LV; Tg = -60 ° C; melting point <25 ° C), 22.06 g (22.06 mmol) of a polytetramethylene glycol with a number average molecular weight of 1000 (purchased from PTG, South Korea, with a brand name of PTMEG-1000; Tg = -76 ° C; melting point = 24 ° C), 4.0 g of 1,3-diethylimidazole bis (trifluoromethanesulfonyl) imide salt (melting point = 12.4 ° C), 3.50 g of fumed silica HDK H18, 2.1 g of 3-isocyanate propyltrimethoxysilane and 1.5 g of a water absorbent Additive TI, heated to 110°C, vacuum dehydrated for 2h under stirring conditions of 150r / min, then cooled to 80°C, 44.48g (264.741mmol) of hexamethylene diisocyanate (HDI) and 0.3g of dibutyltin dilaurate were added, reacted for 2h under stirring conditions of 150r / min, and then discharged to obtain an electrically detachable one-component reactive polyurethane hot melt adhesive, which was vacuum sealed for storage. The content of isocyanate groups in the electrically detachable one-component reactive polyurethane hot melt adhesive is 18.53%.

[0040] Example 4

[0041] By weight, 33.35 g (22.06 mmol) of a liquid polyester diol with a number average molecular weight of 3500 (Hoopol-F37031; Tg = -30 ° C; melting point <25 ° C), 14.29 g (4.764 mmol) of a liquid polyether diol with a number average molecular weight of 3000 (Dow Voranol WD2130; Tg <0 ° C; melting point <25 ° C), 15.0 g of hexyltriethylammonium bis (trifluoromethanesulfonyl) imide salt (melting point = 20 ° C), 7.50 g of fumed silica TS610, 0.9 g of 3-aminopropyltrimethoxysilane and 0.3 g of water absorbent Additive OF, heated to 110°C, vacuum dehydrated for 2h under stirring conditions of 150r / min, then cooled to 80°C, added 28.56g (128.636mmol) of isophorone diisocyanate (IPDI) and 0.1g of zinc isooctanoate, reacted for 2h under stirring conditions of 150r / min, and then discharged to obtain an electrically detachable one-component reactive polyurethane hot melt adhesive, which was vacuum sealed for storage. The content of isocyanate groups in the electrically detachable one-component reactive polyurethane hot melt adhesive is 9.60%.

[0042] Example 5

[0043] By weight, 37.51 g (18.753 mmol) of polycaprolactone diol with a number average molecular weight of 2000 (Daicel PLACCEL L220AL; Tg <0°C; melting point = 0-5°C), 9.38 g (9.376 mmol) of liquid polyester diol with a number average molecular weight of 1000 (Stepanpol PD-110LV; Tg = -60°C; melting point <25°C), 2.0 g of N-butyl-N-methylpyrrolidine bisfluorosulfonyl imide salt (melting point = -15°C), 2.0 g of fumed silica AEROSIL R202, 2.5 g of 3-acryloxypropyltrimethoxysilane and 1.3 g of water absorbent Siliporite SA1702 was heated to 110°C, vacuum dehydrated for 2 hours under stirring conditions of 150 r / min, then cooled to 80°C, 44.22 g (168.773 mmol) of dicyclohexylmethane-4,4'-diisocyanate (HMDI) and 1.1 g of bismuth isooctanoate were added, and the mixture was reacted for 2 hours under stirring conditions of 150 r / min, and then discharged to obtain an electrically detachable one-component reactive polyurethane hot melt adhesive, which was vacuum sealed for storage. The content of isocyanate groups in the electrically detachable one-component reactive polyurethane hot melt adhesive was 11.81%.

[0044] Comparative Example 1

[0045] By weight, 42.59 g (12.169 mmol) of polyester diol with a number average molecular weight of 3500 (Dynacoll 7380; melting point = 70°C), 12.17 g (6.085 mmol) of polyester diol with a number average molecular weight of 2000 (Dynacoll 7110; Tg = 10°C; melting point < 25°C), 12.17 g (6.085 mmol) of liquid polyether diol with a number average molecular weight of 2000 (Dow Voranol WD2130; Tg < 0°C; melting point < 25°C), 20.0 g of thermoplastic acrylic resin BM19 (Tg = 75°C), 0.5 g of 3-mercaptopropyltrimethoxysilane and 0.3 g of water absorbent Additive OF, heated to 110°C, vacuum dehydrated for 2h under stirring conditions of 150r / min, then cooled to 80°C, 12.17g (48.677mmol) of diphenylmethane-4,4'-diisocyanate (MDI) and 0.1g of stannous octoate were added, reacted for 2h under stirring conditions of 150r / min, and then discharged to obtain a reference one-component reactive polyurethane hot melt adhesive, which was vacuum sealed for storage. The content of isocyanate groups in the reference one-component reactive polyurethane hot melt adhesive was 2.56%.

[0046] Comparative Example 2

[0047] By weight, 39.39 g (10.504 mmol) of polyester diol with a number average molecular weight of 3750 (Hoopol F3000; melting point = 71°C), 21.01 g (10.504 mmol) of liquid polyether diol with a number average molecular weight of 2000 (Dow Voranol 2120; Tg <0°C; melting point <25°C), 17.0 g of thermoplastic acrylic resin BM751 (Tg = 49°C), 5.0 g of 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (melting point = -12°C), 5.0 g of propylene carbonate, 1.2 g of 3-mercaptopropyltrimethoxysilane and 0.7 g of water absorbent Additive OF, heated to 110°C, vacuum dehydrated for 2h under stirring conditions of 150r / min, then cooled to 80°C, added 10.50g (42.015mmol) of diphenylmethane-4,4'-diisocyanate (MDI) and 0.2g of stannous octoate, reacted for 2h under stirring conditions of 150r / min, and then discharged to obtain a reference electrically detachable one-component reactive polyurethane hot melt adhesive, which was vacuum sealed and stored. The content of isocyanate groups in the reference electrically detachable one-component reactive polyurethane hot melt adhesive is 1.76%.

[0048] Comparative Example 3

[0049] A reactive polyurethane hot melt adhesive was prepared in the same manner as in Example 1, except that the low-viscosity polyol compound used in Example 1 was replaced with a polyol having a high melting point or high Tg, as follows:

[0050] By weight, 18.37 g (6.124 mmol) of polyester diol with a number average molecular weight of 3000 (Hoopol F-580; melting point = 50°C), 21.43 g (6.124 mmol) of polyester diol with a number average molecular weight of 3500 (Hoopol F5630; Tg = 16°C), 12.25 g (6.124 mmol) of polycarbonate diol with a number average molecular weight of 2000 (UH-CARB200; melting point = 50°C), 7.00 g of 1-ethyl-3-methylimidazolium tetrafluoroborate (melting point = 15°C), 5.0 g of fumed silica HDK H20, 1.0 g of 3-mercaptopropyltrimethoxysilane, and 0.2 g of water absorbent Additive TI, heated to 110°C, vacuum dehydrated for 2h under stirring conditions of 150r / min, then cooled to 80°C, 34.45g (137.786mmol) of diphenylmethane-4,4'-diisocyanate (MDI) and 0.3g of stannous octoate were added, reacted for 2h under stirring conditions of 150r / min, and then discharged to obtain a reference electrically detachable one-component reactive polyurethane hot melt adhesive, which was vacuum sealed for storage. The content of isocyanate groups in the reference electrically detachable one-component reactive polyurethane hot melt adhesive is 10.03%.

[0051] Comparative Example 4

[0052] An electrically detachable reactive polyurethane hot melt adhesive was prepared in the manner of Example 1, except that the molar equivalent ratio of the isocyanate group in the polyisocyanate compound to the hydroxyl group in the low-viscosity polyol compound in Example 1 was adjusted from 7.5:1 to 2:1, as follows:

[0053] By weight, 25.95 g (8.65 mmol) of a liquid polycarbonate diol with a number average molecular weight of 3000 (Kuraraypolyol C3090; Tg = -42 ° C; melting point <25 ° C), 30.28 g (8.65 mmol) of a liquid polyester diol with a number average molecular weight of 3500 (Dynacoll 7230; Tg = -30 ° C; melting point <25 ° C), 17.30 g (8.65 mmol) of a liquid polyester diol with a number average molecular weight of 2000 (stepanpol PH-56; Tg = -15 ° C; melting point <25 ° C), 7.00 g of 1-ethyl-3-methylimidazolium tetrafluoroborate (melting point = 15 ° C), 5.0 g of fumed silica HDK H20, 1.0 g of 3-mercaptopropyltrimethoxysilane and 0.2 g of a water absorbent Additive TI, heated to 110°C, vacuum dehydrated for 2h under stirring conditions of 150r / min, then cooled to 80°C, 12.98g (51.90mmol) of diphenylmethane-4,4'-diisocyanate (MDI) and 0.3g of stannous octoate were added, reacted for 2h under stirring conditions of 150r / min, and then discharged to obtain a reference electrically detachable one-component reactive polyurethane hot melt adhesive, which was vacuum sealed and stored. The content of isocyanate groups in the reference electrically detachable one-component reactive polyurethane hot melt adhesive is 2.18%.

[0054] Comparative Example 5

[0055] An electrically detachable reactive polyurethane hot melt adhesive was prepared in the manner of Example 1, except that the 1-ethyl-3-methylimidazolium tetrafluoroborate in Example 1 was removed, as follows:

[0056] By weight, 18.37 g (6.124 mmol) of a liquid polycarbonate diol with a number average molecular weight of 3000 (Kuraraypolyol C3090; Tg = -42 ° C; melting point <25 ° C), 21.43 g (6.124 mmol) of a liquid polyester diol with a number average molecular weight of 3500 (Dynacoll 7230; Tg = -30 ° C; melting point <25 ° C), 12.25 g (6.124 mmol) of a liquid polyester diol with a number average molecular weight of 2000 (stepanpol PH-56; Tg = -15 ° C; melting point <25 ° C), 5.0 g of fumed silica HDK H20, 1.0 g of 3-mercaptopropyltrimethoxysilane and 0.2 g of a water absorbent Additive TI, heated to 110°C, vacuum dehydrated for 2h under stirring conditions of 150r / min, then cooled to 80°C, 34.45g (137.786mmol) of diphenylmethane-4,4'-diisocyanate (MDI) and 0.3g of stannous octoate were added, reacted for 2h under stirring conditions of 150r / min, and then discharged to obtain a reference electrically detachable one-component reactive polyurethane hot melt adhesive, which was vacuum sealed for storage. The content of isocyanate groups in the reference electrically detachable one-component reactive polyurethane hot melt adhesive is 10.03%.

[0057] Test Case

[0058] The samples of the embodiment and the comparative example were subjected to comparative tests in the following manner:

[0059] (1) Viscosity at 25°C: The polyurethane hot melt adhesive samples obtained in the above embodiments and comparative examples were respectively sampled into a cone-plate viscometer, and the viscosity of the adhesive was tested at 25°C and 1 rpm using the cone-plate viscometer. The results are shown in Table 1.

[0060] (2) Bonding strength before and after power on:

[0061] Bonding strength before power on: Use a dispensing machine to dispense the polyurethane hot melt adhesive obtained in the above embodiments and comparative examples at room temperature (if it is solid at room temperature, the dispensing temperature is set at 110°C), apply a 25mm×4mm rectangular adhesive line on the stainless steel substrate, and then use a 365nm UV-LED light source to irradiate the glue at 2000mJ / cm 2 After the irradiation, another stainless steel substrate was bonded to the stainless steel substrate. After bonding, the sample was cured for 48 hours in an environment of 25°C and 50% RH. Then, a universal material testing machine was used to run the prepared bonding sample along the shear direction at a speed of 10 mm / min until the bonding of the sample failed. The maximum force value displayed by the instrument was recorded, and the shear bonding strength of the polyurethane hot melt adhesive to the stainless steel substrate before power was applied was calculated in combination with the bonding area. The results are shown in Table 1.

[0062] Adhesion strength after power on: Use a dispensing machine to dispense the polyurethane hot melt adhesive obtained in the above embodiments and comparative examples at room temperature (if it is solid at room temperature, the dispensing temperature is set at 110°C), apply a 25mm×4mm rectangular adhesive line on the stainless steel substrate, and then use a 365nm UV-LED light source to irradiate the glue at 2000mJ / cm 2 After the irradiation, another stainless steel substrate is bonded to the stainless steel substrate. After the bonding is completed, the sample is cured in an environment of 25°C and 50% RH for 48 hours. Then, the positive and negative wires of the DC power supply are clamped at both ends of the shear sample, and the power is turned on for a certain period of time at a certain voltage. After the power is turned on, the shear sample is removed, and the universal material testing machine is used to run the prepared bonding sample along the shear direction at a speed of 10mm / min until the sample fails to bond. The maximum force value displayed by the instrument is recorded, and the shear bonding strength of the polyurethane hot melt adhesive to the stainless steel substrate after power is turned on is calculated in combination with the bonding area. The results are shown in Table 1.

[0063] (3) High temperature and high humidity resistance (double 85 aging): The polyurethane hot melt adhesive obtained in the above embodiments and comparative examples was dispensed at room temperature using a dispensing machine (if it is solid at room temperature, the dispensing temperature is set at 110°C), and a rectangular glue line of 25 mm × 4 mm was coated on a stainless steel substrate. Then, a 365 nm UV-LED light source was used to irradiate the glue at 2000 mJ / cm 2 After the irradiation, another stainless steel substrate was bonded to the stainless steel substrate. After bonding, the sample was cured in an environment of 25°C and 50% RH for 48 hours, and then the bonded shear sample was placed in a high temperature and high humidity oven at 85°C and 85% RH for 7 days. After that, the universal material testing machine was used to run the prepared bonding sample along the shear direction at a speed of 10mm / min until the sample failed to bond. The maximum force value displayed by the instrument was recorded, and the shear bonding strength of the polyurethane hot melt adhesive to the stainless steel substrate after high temperature and high humidity aging was calculated in combination with the bonding area. The results are shown in Table 1.

[0064] Table 1

[0065]

[0066] As can be seen from the results of Table 1, the electrically detachable one-component reactive polyurethane hot melt adhesive provided by the present invention has a lower melt viscosity at room temperature, and can be directly dispensed at room temperature, which significantly improves the defect that the reactive polyurethane hot melt adhesive needs to be heated for gluing, increases the convenience of using the adhesive, and reduces the risk of operators being scalded during the use of heating equipment. According to practical experience, if the bonding strength at room temperature is less than 2.0MPa, it means that the polyurethane hot melt adhesive is detachable, otherwise it is not detachable. As can be seen from the results of Table 1, the reactive polyurethane hot melt adhesive provided by the present invention has excellent final bonding strength after curing, and the bonding strength after power-on can be significantly attenuated, and can even fall off directly, with excellent electrical disassembly performance. In addition, the electrically disassemblyable one-component reactive polyurethane hot melt adhesive provided by the present invention also has excellent high temperature and high humidity stability. In summary, the polyurethane hot melt adhesive provided by the present invention has a low melt viscosity, can be dispensed at room temperature, has a high final bonding strength, and has a disassembly function under power-on conditions, and has broad practical application prospects.

[0067] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and purpose of the present invention.

Claims

1. An electrically detachable one-component reactive polyurethane hot melt adhesive, characterized in that: The electrically detachable one-component reactive polyurethane hot melt adhesive has a viscosity range of 1000-150000 cps at 25°C and a bonding strength attenuation rate of more than 80% after being energized at a voltage of 1-100V. The content of isocyanate groups in the electrically detachable one-component reactive polyurethane hot melt adhesive is 5-20%.

2. The electrically detachable one-component reactive polyurethane hot melt adhesive according to claim 1, characterized in that: The raw materials for preparing the electrically detachable one-component reactive polyurethane hot melt adhesive contain polyisocyanate compounds, low-viscosity polyol compounds, ionic liquids, and optional rheology modifiers, silane coupling agents, water absorbents, and catalysts. The molar equivalent ratio of isocyanate groups in the polyisocyanate compounds to hydroxyl groups in the low-viscosity polyol compounds is (5-10):1, and the glass transition temperature of the low-viscosity polyol compounds is below 0°C and the melting point is below 40°C.

3. The electrically detachable one-component reactive polyurethane hot melt adhesive according to claim 2, characterized in that: Based on the total weight of the raw materials for preparing the electrically detachable one-component reactive polyurethane hot melt adhesive, the total content of the polyisocyanate compound and the low-viscosity polyol compound is 75-92%, the content of the ionic liquid is 2-15%, the content of the rheology modifier is 2-10%, the content of the silane coupling agent is 0.1-5%, the content of the water absorbent is 0.1-2%, and the content of the catalyst is 0.1-2%.

4. The electrically detachable one-component reactive polyurethane hot melt adhesive according to claim 2, characterized in that: The polyisocyanate compound is selected from at least one of isophorone diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, diphenylmethane-4,4'-diisocyanate, diphenylmethane-2,4'-diisocyanate, hydrogenated xylylene diisocyanate, 1,5-naphthalene diisocyanate, 1,5-pentane diisocyanate, 1,4-phenylene diisocyanate, xylylene diisocyanate, tetramethylxylene diisocyanate, norbornane diisocyanate, lysine diisocyanate, triphenylmethane triisocyanate, thiophosphoric acid triphenyl isocyanate and 1,6,11-undecane triisocyanate.

5. The electrically detachable one-component reactive polyurethane hot melt adhesive according to claim 2, characterized in that: The number average molecular weight of the low-viscosity polyol compound is 400-6000 g / mol; the low-viscosity polyol compound is selected from at least one of liquid polyester polyol, liquid polyether polyol, liquid polycarbonate polyol, liquid polycaprolactone polyol, fatty acid dimer diol, castor oil derivative polyol and terminal hydroxyl polybutadiene polyol.

6. The electrically detachable one-component reactive polyurethane hot melt adhesive according to claim 2, characterized in that: The melting point of the ionic liquid is below 25°C; Preferably, the ionic liquid is composed of cations and anions, the cations are selected from at least one of imidazole cations, pyrrole cations, quaternary ammonium salt cations, quaternary phosphonium salt cations, pyrrolidine cations and piperidine cations, and the anions are selected from at least one of trifluoromethanesulfonate anions, tetrafluoroborate anions, hexafluorophosphate anions, bisfluoromethanesulfonyl imide anions, hydrogen sulfate anions, ethyl sulfate anions and p-toluenesulfonate anions; Preferably, the ionic liquid is selected from 1-butyl-3-methylimidazolium trifluoromethanesulfonate, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-ethyl-2,3-dimethylimidazolium trifluoromethanesulfonate, 1-octyl-3-methylimidazolium trifluoromethanesulfonate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-propyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-2,3-dimethylimidazolium tetrafluoroborate, 1-propyl-2,3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium ethyl sulfate, 1-ethyl-2,3-dimethylimidazolium ethyl sulfate, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide at least one of salt, 1,3-diethylimidazolium bis(trifluoromethanesulfonyl)imide salt, 1-propyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, 1-hexyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, 1,2-dimethyl-3-propylimidazolium bis(trifluoromethanesulfonyl)imide, 1-ethyl-2,3-dimethylimidazolium bis(trifluoromethanesulfonyl)imide salt, N-butylpyridinium tetrafluoroborate, hexyltriethylammonium bis(trifluoromethanesulfonyl)imide salt, methyltrioctylphosphonium bis(trifluoromethanesulfonyl)imide salt, N-butyl-N-methylpyrrolidine bis(trifluoromethanesulfonyl)imide salt, N-butyl-N-methylpyrrolidine trifluoromethanesulfonate and N-propyl-N-methylpiperidinium bis(trifluoromethanesulfonyl)imide salt.

7. The electrically detachable one-component reactive polyurethane hot melt adhesive according to claim 2, characterized in that: The rheology modifier is fumed silica.

8. The electrically detachable one-component reactive polyurethane hot melt adhesive according to claim 2, characterized in that: The silane coupling agent is selected from 3-mercaptopropyl trimethoxysilane, 3-mercaptopropyl triethoxysilane, 3-mercaptopropyl methyl dimethoxysilane, 3-mercaptopropyl methyl diethoxysilane, 3-glycidoxypropyl trimethoxysilane, 3-glycidoxypropyl triethoxysilane, 3-glycidoxypropyl methyl dimethoxysilane, 3-glycidoxypropyl methyl diethoxysilane, 2-(3,4-epoxycyclohexyl)ethyl trimethoxysilane, 3-glycidoxypropyl methyl diethoxysilane, 3-aminopropyl trimethoxysilane, 3-aminopropyl triethoxysilane, 3-(2 -aminoethyl)aminopropyltrimethoxysilane, 3-(2-aminoethyl)aminopropyltriethoxysilane, 3-(2-aminoethyl)aminopropylmethyldimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 3-(meth)acryloxypropylmethyldimethoxysilane, 3-(meth)acryloxypropylmethyldiethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane and at least one of 3-isocyanatepropyltrimethoxysilane.

9. The electrically detachable one-component reactive polyurethane hot melt adhesive according to claim 2, characterized in that: The water absorbent is selected from at least one of a molecular sieve desiccant, an oxazolidine dehydrating agent, p-toluenesulfonyl isocyanate and triethyl orthoformate.

10. The electrically detachable one-component reactive polyurethane hot melt adhesive according to claim 2, characterized in that: The catalyst is selected from at least one of dibutyltin dilaurate, stannous octoate, zinc isooctanoate, bismuth isooctanoate, triethylamine, diethylenetriamine, triethylenediamine, N-ethylmorpholine and 2,2-dimorpholinyl diethyl ether.

11. The method for preparing the electrically detachable one-component reactive polyurethane hot melt adhesive according to any one of claims 1 to 10, characterized in that: The method comprises uniformly mixing a polyisocyanate compound, a low-viscosity polyol compound, an ionic liquid, and an optional rheology modifier, a silane coupling agent, a water absorbent and a catalyst to obtain an electrically detachable single-component reactive polyurethane hot melt adhesive.

12. The method for preparing the electrically detachable one-component reactive polyurethane hot melt adhesive according to claim 11, characterized in that: The mixing step comprises: S1, dehydrating the low-viscosity polyol compound, the ionic liquid, the rheology modifier, the silane coupling agent and the water absorbent to obtain a pretreated product; S2. Stir the pretreated product, the polyisocyanate compound and the catalyst at 70 to 90° C. for 1 to 5 hours to obtain a one-component reactive polyurethane hot melt adhesive.

13. Use of the electrically detachable one-component reactive polyurethane hot melt adhesive according to any one of claims 1 to 10 in bonding electronic products.

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