Photoresponse tackifier as well as preparation method and application thereof

Abstract

The invention provides a photoresponse tackifier and a preparation method and application thereof, the structural general formula of the photoresponse tackifier is A-B-C, A is an active vinyl end group capable of participating in polymerization, B is a photoresponse group, and C is a siloxane group or a silane coupling end group. The photoresponse tackifier provided by the invention has good compatibility with an organic silicon material, and can significantly improve the initial bonding force of organic silicon to various base materials; through molecular structure design, the synergistic effect of photoresponse and tackifying functions is realized, and other excellent properties of the organic silicon body are not influenced. The adhesive property of the tackifier can be regulated and controlled by light (such as ultraviolet rays) with specific wavelength, so that the adhesive strength is rapidly and greatly reduced.

Description

Technical Field

[0001] This invention belongs to the field of tackifier technology, and relates to a photoresponsive tackifier, its preparation method and application, specifically to a photosensitive tackifier and its preparation method for improving the adhesion between organosilicon materials (such as silicone rubber, silicone gel, silicone resin) and various substrates, wherein the adhesion strength can be reversibly controlled by light irradiation. Background Technology

[0002] Silicone materials are widely used in electronic packaging, medical devices, pressure-sensitive tapes, and the automotive industry due to their excellent high and low temperature resistance, weather resistance, electrical insulation, physiological inertness, and flexibility. However, the non-polar and chemically inert nature of polysiloxane molecular chains results in poor adhesion to most substrates (such as metals, glass, and engineering plastics), which severely limits their use in high-reliability applications. Therefore, providing a high-performance tackifier that enhances the adhesion of silicone materials to various substrates without adversely affecting their performance has become a pressing technical problem.

[0003] To solve the adhesion problem of silicone, existing technologies typically employ the following methods:

[0004] Physical surface treatments, such as corona treatment, plasma treatment, or flame treatment, activate the substrate surface. This method is expensive, the treatment effect is unstable and easily degrades over time, it is unsuitable for complex-shaped devices, and adjustments cannot be made after bonding.

[0005] Adding tackifiers: Adding tackifiers to silicone formulations is currently the most mainstream and effective method. Commonly used tackifiers include: silane coupling agents: such as silanes containing amino, epoxy, or methacryloxy groups, silicone oligomers or resins containing tackifying groups, etc. They improve adhesion by forming chemical bonds or strong interactions with the substrate surface through their own functional groups.

[0006] While the aforementioned tackifier technologies improve the adhesive properties of silicone to some extent, they share a common, inherent drawback: once bonded, its strength is permanent or quasi-permanent, making controllable and reversible bonding impossible. This "irreversible" characteristic introduces significant limitations in many advanced applications.

[0007] In electronic product packaging and repair: Using high-strength silicone-based encapsulations or mounting devices almost inevitably damages expensive components or precision substrates when rework, replacement, or recycling of specific parts. In temporary mounting and transfer: In semiconductor processing, display manufacturing, and other fields, components often need to be temporarily fixed to a support platform and then removed without damage after processing. Current technology struggles to meet this demand for "strong temporary adhesion." In reusable adhesive interfaces: Existing silicone bonding technologies are inadequate for structures requiring multiple assembly and disassembly.

[0008] Therefore, there is an urgent need in the field for a smart tackifier that can provide sufficient initial adhesive force and achieve a rapid and controllable decrease in adhesive force under specific external stimuli. Summary of the Invention

[0009] To address the shortcomings of existing technologies, the present invention aims to provide a photoresponsive tackifier (i.e., a tackifier with photoresponsive properties), its preparation method, and its application. Specifically, it provides a photoresponsive tackifier for organosilicon, its preparation method, and its application. More specifically, it provides a photosensitive tackifier and its preparation method for improving the adhesion between organosilicon materials (such as silicone rubber, silicone gel, and silicone resin) and various substrates, whose adhesion strength can be reversibly controlled by light irradiation.

[0010] To achieve this objective, the present invention adopts the following technical solution:

[0011] In a first aspect, the present invention provides a photoresponsive tackifier, wherein the general structural formula of the photoresponsive tackifier is ABC, wherein A is an active vinyl end group that can participate in polymerization, B is a photoresponsive group (this is the core improvement of the present invention), and C is a siloxane or silane coupling end group.

[0012] The photoresponsive tackifier provided by this invention comprises a reactive group at one end, a siloxane chain segment at the other end, and a photosensitive group connected in the middle. It can be used in organosilicon systems. The addition of this tackifier can effectively improve the adhesive strength of the organosilicon system without adversely affecting the properties of the organosilicon material itself. After ultraviolet light irradiation, the adhesive force can be rapidly reduced, achieving separation. The photoresponsive tackifier provided by this invention expands its application areas, such as the temporary fixation and non-destructive disassembly of precision components. In microelectronic assembly, optical component polishing, and other processes, it can be used to temporarily and firmly fix components. After processing, the components can be easily and non-destructively separated by localized ultraviolet irradiation, avoiding damage caused by physical prying.

[0013] The photoresponsive tackifier provided by this invention exhibits good compatibility with silicone materials and can significantly improve the initial adhesion of silicone to various substrates. Through molecular structure design, a synergistic effect of photoresponsiveness and tackifying function is achieved without affecting other excellent properties of the silicone itself. The adhesive properties of this tackifier can be modulated by light of a specific wavelength (such as ultraviolet light), achieving a rapid and significant decrease in adhesive strength.

[0014] The main problem with silicone materials is their low adhesion, which reduces their applicability and makes them unsuitable for bonding all materials. This invention uses a double-ended coupling agent to enable molecular-level adhesion between the silicone matrix and the bonding substrate, effectively improving the adhesion of the system.

[0015] Traditional silicone materials using tackifiers exhibit permanent or quasi-permanent bond strength once bonded, making controllable and reversible bonding impossible. They also cannot be properly peeled off, leaving significant residue, and the cured silicone material itself is difficult to clean. This invention utilizes a photoresponsive silicone tackifier, which rapidly reduces adhesive strength upon photoresponsiveness. Components can be easily and non-destructively separated via localized ultraviolet irradiation, avoiding damage from physical prying, effectively reducing residue, and facilitating cleaning.

[0016] A represents the active site for the reaction between the tackifier molecule and the organosilicon matrix. Its main function is to participate in the curing reaction of the organosilicon matrix, so that one end of the tackifier is tightly connected to the matrix. The active end group mainly participates in the hydrosilylation reaction inside the organosilicon, so the double bond is the core structure of the active group.

[0017] Preferably, A is selected from CH2=CH-, CH2=CR-, CH2=CH-CH2-O-, CH2=CH-Ph-O-, Any one of them, wherein R is an alkyl group of C4 to C8 (e.g., C4, C5, C6, C7 or C8).

[0018] Preferably, B is a photoresponsive group compatible with the catalyst.

[0019] Preferably, B is a photoresponsive group compatible with platinum catalysts, which is the key innovation and difference of this invention.

[0020] B is the main source of the adhesive force of the tackifier in response to ultraviolet light. Its main function is to respond to ultraviolet light. After being irradiated by ultraviolet light, it decomposes, thereby destroying the original molecular structure of the tackifier. This causes the original adhesive mechanism based on the double-end anchoring of the tackifier molecules to fail, thus achieving a rapid reduction in adhesive force.

[0021] Preferably, B is selected from any one of o-nitrobenzyl, azophenyl, and benzoylmethyl.

[0022] The C is a siloxane or silane coupling end group. The siloxane chain segment is the main source of the adhesive's improved adhesion to the substrate. Its core mechanism is that the siloxane chain segment hydrolyzes to generate silanol groups, which improves the compatibility with the interface and increases the adhesion. At the same time, the generated silanol groups can also undergo dehydration condensation with the hydroxyl groups carried by the water absorbed on the surface of the bonded interface, thereby tightly binding with the bonded interface to form a molecular-level tight bond, further improving the adhesion.

[0023] Preferably, C is selected from any one of trimethoxysilyl, triethoxysilyl, and methyldiethoxysilyl.

[0024] In a second aspect, the present invention provides a method for preparing a photoresponsive tackifier as described in the first aspect, the method comprising the following steps:

[0025] (1) Esterification reaction introduces photosensitive group host: mix photosensitive monomer, triethylamine and organic solvent, cool in ice water bath, then add inhibitor and monomer containing terminal vinyl group. After the addition is complete, remove ice water bath, continue reaction, and post-process to obtain the first intermediate product.

[0026] (2) Hydrosilylation reaction to link siloxane chain segments: The first intermediate product, siloxane monomer and / or silane coupling agent, and organic solvent are mixed, and then a catalyst is added for the first time. The reaction is carried out, and the catalyst is added again during the reaction. After post-treatment, the second intermediate product is obtained.

[0027] (3) Aromatic nucleophilic substitution reaction to introduce active vinyl groups: replacing the para-chlorine atom of the benzene ring with a vinyl group: mixing the second intermediate product, vinyl borate pinacol ester, palladium catalyst, sodium carbonate aqueous solution and organic solvent, reacting, and post-processing to obtain the photoresponsive tackifier.

[0028] Preferably, the photosensitive monomer in step (1) includes any one or a combination of at least two of p-chloro-o-nitrobenzyl alcohol, 4-hydroxy-4'-bromoazobenzene, and 4'-hydroxy-4-bromobenzophenone.

[0029] Preferably, the molar ratio of the photosensitive monomer to triethylamine in step (1) is 1:(0.8~1.2), for example 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, etc.

[0030] Preferably, the organic solvent in step (1) includes anhydrous dichloromethane.

[0031] Preferably, the temperature of the ice-water bath in step (1) is 0~10℃, such as 0℃, 2℃, 3℃, 5℃, 8℃, 10℃, etc., preferably 0~5℃.

[0032] Preferably, the inhibitor in step (1) includes hydroquinone.

[0033] Preferably, the amount of the inhibitor used in step (1) is 0.1% to 1% of the mass of the photosensitive monomer, such as 0.1%, 0.3%, 0.5%, 0.6%, 0.8%, 1%, etc., preferably 0.1% to 0.3%.

[0034] Preferably, the monomer containing terminal vinyl groups in step (1) includes any one or a combination of at least two of acryloyl chloride, methacryloyl chloride, acetyl chloride, allyl chloride, and p-chloromethylstyrene.

[0035] Preferably, the molar ratio of the photosensitive monomer to the monomer containing the terminal vinyl group in step (1) is 1:(1~1.2), such as 1:1, 1:1.1, 1:1.2, etc., preferably 1:(1~1.1).

[0036] Preferably, the addition time of the monomer containing terminal vinyl groups in step (1) is controlled at 2 to 3 hours, such as 2 hours, 2.5 hours, 3 hours, etc., preferably 3 hours.

[0037] Preferably, the total reaction time of step (1) is 10-12 hours, such as 10 hours, 11 hours, 12 hours, etc., and preferably 11-12 hours.

[0038] Preferably, the post-processing in step (1) includes washing and drying.

[0039] Preferably, the siloxane monomer and / or silane coupling agent in step (2) includes any one or a combination of at least two of trimethoxysilane, triethoxysilane, and methyldiethoxysilane.

[0040] Preferably, in step (2), the molar ratio of the first intermediate product to the siloxane monomer and / or silane coupling agent is 1:(1.2~1.5), for example, 1:1.2, 1:1.3, 1:1.4, 1:1.5, etc.

[0041] Preferably, the organic solvent in step (2) includes anhydrous toluene.

[0042] Preferably, the catalyst in step (2) comprises a Karstedt catalyst.

[0043] Preferably, the amount of catalyst added for the first time in step (2) is 10 to 20 ppm of the total mass of the first intermediate product, siloxane monomer and / or silane coupling agent, such as 10 ppm, 12 ppm, 14 ppm, 15 ppm, 16 ppm, 18 ppm, 20 ppm, etc., preferably 20 ppm.

[0044] Preferably, the reaction temperature in step (2) is 60~80℃, such as 60℃, 65℃, 70℃, 75℃, 80℃, etc., and preferably 70~80℃.

[0045] Preferably, the reaction time in step (2) is 8 to 10 hours, such as 8 hours, 9 hours, 10 hours, etc., with 8 to 9 hours being the most preferred.

[0046] Preferably, the addition of catalyst during the reaction process in step (2) specifically includes: adding catalyst once every 2 hours, and the amount of catalyst added each time is 3 to 5 ppm of the total mass of the first intermediate product, siloxane monomer and / or silane coupling agent, such as 3 ppm, 4 ppm, 5 ppm, etc., preferably 5 ppm.

[0047] Preferably, step (2) is carried out under the protection of an inert gas (such as nitrogen or argon).

[0048] Preferably, the post-processing in step (2) includes vacuum rotary evaporation.

[0049] Preferably, in step (3), the molar ratio of the second intermediate product to vinyl borate pinacol ester is 1:(1~1.3), for example 1:1, 1:1.1, 1:1.2, 1:1.3, etc., preferably 1:(1.1~1.2).

[0050] Preferably, the amount of palladium catalyst used in step (3) is 0.1% to 1% of the sum of the mass of the second intermediate product and the vinyl borate pinacol ester, for example, 0.1%, 0.3%, 0.5%, 0.6%, 0.8%, 1%, etc., preferably 0.5%.

[0051] Preferably, the amount of sodium carbonate aqueous solution used in step (3) is such that the pH value of the system is 9~10, for example 9, 9.2, 9.3, 9.5, 9.6, 9.8, 10, etc.

[0052] Preferably, the organic solvent in step (3) includes toluene and / or ethanol.

[0053] Preferably, the reaction temperature in step (3) is 70~90℃, such as 70℃, 75℃, 80℃, 85℃, 90℃, etc., with 70~80℃ being the most preferred.

[0054] Preferably, the reaction time in step (3) is 12 to 24 hours, such as 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 22 hours, 24 hours, etc., with 12 to 16 hours being the most preferred.

[0055] Preferably, step (3) is carried out under the protection of an inert gas.

[0056] Preferably, the post-processing in step (3) includes separation, extraction, washing, and drying.

[0057] Thirdly, the present invention provides a photosensitive silicone adhesive material, wherein the raw materials for preparing the photosensitive silicone adhesive material include vinyl silicone oil, hydrogen-containing silicone oil, tackifier, catalyst, and inhibitor, and the tackifier includes the photoresponsive tackifier as described in the first aspect or the photoresponsive tackifier prepared according to the preparation method described in the second aspect.

[0058] Preferably, the molar ratio of vinyl groups in the vinyl silicone oil to silane groups in the hydrogen-containing silicone oil is 1:(1~1.2), for example, 1:1, 1:1.1, 1:1.2, etc.

[0059] Preferably, the amount of the tackifier is 3% to 10% of the sum of the mass of the vinyl silicone oil and the hydrogen-containing silicone oil, for example, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, etc., preferably 5% to 10%.

[0060] Preferably, the amount of catalyst used is 5 to 20 ppm of the sum of the mass of vinyl silicone oil and hydrogen-containing silicone oil, such as 5 ppm, 6 ppm, 8 ppm, 10 ppm, 12 ppm, 14 ppm, 15 ppm, 16 ppm, 18 ppm, 20 ppm, etc.

[0061] Preferably, the inhibitor in the raw materials for preparing the photosensitive silicone adhesive material includes ethynylcyclohexanol.

[0062] Preferably, the amount of the inhibitor is 1 to 4 ppm of the sum of the mass of vinyl silicone oil and hydrogen-containing silicone oil, for example, 1 ppm, 2 ppm, 3 ppm, 4 ppm, etc.

[0063] Fourthly, the present invention provides a method for preparing a photosensitive silicone adhesive material as described in the third aspect, the method comprising the following steps:

[0064] The tackifier is mixed with vinyl silicone oil, then a catalyst and an inhibitor are added, and the mixture is mixed a second time. Then, hydrogen-containing silicone oil is added, and the mixture is mixed a third time to obtain the photosensitive silicone adhesive material.

[0065] Preferably, the rotation speed of the second mixing is 800~1500 rpm, such as 800 rpm, 900 rpm, 1000 rpm, 1100 rpm, 1200 rpm, 1300 rpm, 1400 rpm, 1500 rpm, etc., with 800~1000 rpm being the most preferred.

[0066] Preferably, the second mixing time is 8 to 24 hours, such as 8 hours, 10 hours, 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 22 hours, 24 hours, etc., with 8 to 12 hours being the most preferred.

[0067] Preferably, the rotation speed of the third mixing is 300~500 rpm, such as 300 rpm, 350 rpm, 400 rpm, 450 rpm, 500 rpm, etc., with 300 rpm being the most preferred.

[0068] Preferably, the third mixing time is 8 to 12 hours, such as 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, etc., and more preferably 10 to 12 hours.

[0069] Preferably, during the third mixing process, the system temperature is controlled to be below 35°C, for example, 30°C, 25°C, 20°C, etc.

[0070] Preferably, the third mixing is followed by a filtering step.

[0071] Preferably, the filtration is performed using a 0.45~0.22μm filter element.

[0072] Compared with the prior art, the present invention has the following beneficial effects:

[0073] The photoresponsive tackifier provided by this invention comprises a reactive group at one end, a siloxane chain segment at the other end, and a photosensitive group connected in the middle. It can be used in organosilicon systems. The addition of this tackifier can effectively improve the adhesive strength of the organosilicon system without adversely affecting the properties of the organosilicon material itself. After ultraviolet light irradiation, the adhesive force can be rapidly reduced, achieving separation. The photoresponsive tackifier provided by this invention expands its application areas, such as the temporary fixation and non-destructive disassembly of precision components. In microelectronic assembly, optical component polishing, and other processes, it can be used to temporarily and firmly fix components. After processing, the components can be easily and non-destructively separated by localized ultraviolet irradiation, avoiding damage caused by physical prying. Attached Figure Description

[0074] Figure 1 This is a schematic diagram illustrating the bonding between the silicone adhesive material and the substrate provided in Application Example 1, and the mechanism for reducing adhesive force based on photoresponse. Detailed Implementation

[0075] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0076] Example 1

[0077] This embodiment provides a photoresponsive tackifier, the preparation method of which includes the following steps:

[0078] (1) Esterification reaction introduces photosensitive group host: react p-chloro-o-nitrobenzyl alcohol with acryloyl chloride to obtain the first intermediate product (p-chloro-o-nitrobenzyl acrylate).

[0079] In a dry reaction flask, p-chloro-o-nitrobenzyl alcohol and an equimolar amount of triethylamine were dissolved in anhydrous dichloromethane. The mixture was cooled in an ice-water bath (0-5°C). While stirring, acryloyl chloride containing the inhibitor hydroquinone was slowly added dropwise to the reaction solution through a constant-pressure dropping funnel. Temperature and dropping rate were strictly controlled to prevent localized overheating and side reactions. After the addition was complete, the ice bath was removed, and the reaction solution was allowed to slowly rise to room temperature. Stirring continued until the reaction was complete. After the reaction was complete, the reaction solution was washed with dilute hydrochloric acid to remove excess alkali and salt. The organic phase was dried over anhydrous sodium sulfate. After filtration, the solvent was removed by rotary evaporation under reduced pressure.

[0080] The molar ratio of p-chloro-o-nitrobenzyl alcohol to acryloyl chloride was 1:1.1, and the amount of hydroquinone inhibitor was 0.5% of that of p-chloro-o-nitrobenzyl alcohol. The dropping time of acryloyl chloride was controlled at 3 hours, and the total reaction time was controlled at 11 hours.

[0081] (2) Hydrosilylation reaction to graft siloxane segments: The acrylate double bond of the product from the previous step is subjected to platinum-catalyzed addition with triethoxysilane to graft siloxane segments.

[0082] In a dry reactor, the first intermediate (p-chloro-o-nitrobenzyl acrylate) and triethoxysilane were dissolved in anhydrous toluene. The system was purged with an inert gas (such as nitrogen or argon) to ensure an oxygen-free environment and prevent catalyst deactivation and double bond polymerization. The Karstedt catalyst was added for the first time under an inert atmosphere. The reaction mixture was heated and stirred. The reaction was continued at 70°C for 8 hours, with Karstedt catalyst added every 2 hours. After the reaction was complete, the mixture was cooled to room temperature, and the solvent and excess triethoxysilane were removed by rotary evaporation under reduced pressure to obtain the crude product, which is the second intermediate.

[0083] The molar ratio of the first intermediate product to triethoxysilane is 1:1.2; the amount of catalyst added for the first time is 20 ppm of the total mass of the first intermediate product and triethoxysilane, and the amount of catalyst added each time is 5 ppm of the total mass of the first intermediate product and triethoxysilane.

[0084] (3) Aromatic nucleophilic substitution reaction to introduce active vinyl groups: replacing the para-chlorine atom of the benzene ring with a vinyl group.

[0085] The second intermediate, vinyl borate pinacol ester, palladium catalyst, and aqueous sodium carbonate solution were added to a reaction flask. Toluene and ethanol were added as solvents, and the system was protected under nitrogen atmosphere. The mixture was heated to a temperature with vigorous stirring. After the reaction was complete, the mixture was cooled to room temperature, and the aqueous phase was extracted with ethyl acetate. The combined organic phases were washed with brine and dried over anhydrous sodium sulfate. After filtration, the mixture was concentrated under reduced pressure to obtain the final target product.

[0086] The molar ratio of the second intermediate to vinylboronic acid pinacol ester is 1:1.2; the amount of palladium catalyst used is 0.5% of the sum of the mass of the second intermediate and vinylboronic acid pinacol ester; the amount of sodium carbonate aqueous solution used is to make the pH of the system 9-10; the reaction temperature is controlled at 80℃ and the total reaction time is controlled at 14h.

[0087] Example 2

[0088] The only difference between this embodiment and Embodiment 1 is that the triethoxysilane in step (2) is replaced with an equimolar amount of methyldiethoxysilane.

[0089] Example 3

[0090] The only difference between this embodiment and Example 1 is that the p-chloro-o-nitrobenzyl alcohol in step (1) is replaced with an equimolar amount of 4-hydroxy-4'-bromoazobenzene.

[0091] Example 4

[0092] The only difference between this embodiment and Example 1 is that the p-chloro-o-nitrobenzyl alcohol in step (1) is replaced with an equimolar amount of 4'-hydroxy-4-bromobenzophenone.

[0093] Comparative Example 1

[0094] This comparative example provides a conventional tackifier, specifically allyltriethoxysilane, which contains terminal vinyl and terminal siloxane groups but lacks a photosensitive group at the intermediate site.

[0095] Comparative Example 2

[0096] The difference between this comparative example and Example 1 is that the intermediate product obtained in step (1) is used, and step (2) is skipped to directly carry out the reaction described in step (3). The resulting tackifier contains photosensitive groups and terminal vinyl groups, but no terminal siloxane groups.

[0097] Comparative Example 3

[0098] The difference between this comparative example and Example 1 is that the p-chloro-o-nitrobenzyl alcohol in step (1) is replaced with an equimolar amount of o-nitrobenzyl alcohol, and the reaction step (3) is omitted. The resulting tackifier contains terminal siloxane groups and photosensitive groups, but no terminal vinyl groups.

[0099] Application Example 1

[0100] This application example provides a photosensitive silicone adhesive material, the raw materials for preparing the photosensitive silicone adhesive material include vinyl silicone oil, hydrogen-containing silicone oil, tackifier, catalyst, and inhibitor;

[0101] Among them, the vinyl silicone oil is DY-V401 (Shandong Dayi Chemical Co., Ltd.), the hydrogen-containing silicone oil is DY-H212 (Shandong Dayi Chemical Co., Ltd.), the tackifier is the photo-responsive tackifier provided in Example 1, the catalyst is the Karstedt catalyst (Neutron Star Chemical Co., Ltd.), and the inhibitor is ethynylcyclohexanol.

[0102] The molar ratio of vinyl groups in vinyl silicone oil to silane groups in hydrogen-containing silicone oil is 1:1.1; the amount of tackifier is 5% of the sum of the mass of vinyl silicone oil and hydrogen-containing silicone oil; the amount of catalyst is 10 ppm of the sum of the mass of vinyl silicone oil and hydrogen-containing silicone oil; and the amount of inhibitor is 2 ppm of the sum of the mass of vinyl silicone oil and hydrogen-containing silicone oil.

[0103] The preparation method of photosensitive silicone adhesive material includes the following steps:

[0104] Vinyl silicone oil was added to a stirrer, and then a thickener was slowly added dropwise using a peristaltic pump over a period of 20 minutes. After thorough mixing, a catalyst and inhibitor were added, and the mixture was stirred (at 1000 rpm for 12 hours) until homogeneous. Then, hydrogen-containing silicone oil was slowly added dropwise using a peristaltic pump over a period of 2 hours. The mixture was stirred at low speed (at 300 rpm for 12 hours) until homogeneous. Cooling water was introduced during the stirring process to keep the system temperature below 35°C. After mixing, the mixture was filtered using a filter cartridge to obtain the photosensitive silicone adhesive material.

[0105] Application Example 2

[0106] The only difference between this application example and application example 1 is that the amount of tackifier used is 10% of the sum of the mass of vinyl silicone oil and hydrogen-containing silicone oil.

[0107] Application Example 3

[0108] The only difference between this application example and application example 1 is that the tackifier is the photoresponsive tackifier provided in example 2.

[0109] Application Example 4

[0110] The only difference between this application example and application example 1 is that the tackifier is the photoresponsive tackifier provided in example 3.

[0111] Application Example 5

[0112] The only difference between this application example and application example 1 is that the tackifier is the photoresponsive tackifier provided in example 4.

[0113] Comparative Application Example 1

[0114] The only difference between this comparative application example and application example 1 is that the tackifier used is the tackifier provided in comparative example 1.

[0115] Comparative Application Example 2

[0116] The only difference between this comparative application example and application example 1 is that the tackifier used is the tackifier provided in comparative example 2.

[0117] Comparative Application Example 3

[0118] The only difference between this comparative application example and application example 1 is that the tackifier used is the tackifier provided in comparative example 3.

[0119] Comparative Application Example 4

[0120] The only difference between this comparative application example and application example 1 is that the tackifier is a commercially available non-photosensitive silicone tackifier (ACS-MA-9100).

[0121] Comparative Application Example 5

[0122] The only difference between this comparative application example and application example 1 is that the amount of tackifier used is 20% of the sum of the mass of vinyl silicone oil and hydrogen-containing silicone oil.

[0123] The performance of the silicone adhesive materials provided in the application examples and comparative application examples of this invention was tested using the following methods:

[0124] (1) Bonding strength: The above-mentioned silicone adhesive material was spin-coated on the sapphire substrate, and another sapphire substrate was covered on top of the silicone adhesive material. The substrate was heated and pressure bonded at a bonding temperature of 185°C and a bonding time of 25 min. After the silicone adhesive material was completely cured, the two substrates were fixed with a pull-out device. The pulling force was gradually increased to peel off the bonded parts. The maximum stress during the process was recorded, and the maximum bonding strength was calculated based on the substrate area.

[0125] (2) Bond strength after irradiation: The above-mentioned bond strength test samples were irradiated with 365nm ultraviolet light, and the ultraviolet light intensity was selected as 40mW / cm. 2 The irradiation time is 8 minutes, and the bonding strength is tested according to the above-mentioned bonding strength test method after irradiation.

[0126] (3) Young's modulus: The test was conducted using an electronic universal testing machine. The test method was in accordance with GB / T-528 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber".

[0127] (4) Elongation at break: The test was conducted using an electronic universal testing machine. The test method was in accordance with GB / T-528 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber".

[0128] The performance test results are shown in Table 1.

[0129] Table 1

[0130]

[0131] As can be seen from Table 1, when the photoresponsive tackifiers provided in the embodiments of the present invention are used in organosilicon materials, they all have high bonding strength (2.4~3MPa), and the bonding strength is significantly reduced after irradiation (0.1~0.3MPa). At the same time, they have high Young's modulus (0.8~1.3MPa) and elongation at break (350%~405%).

[0132] Compared with Application Example 1, the adhesive strength of the silicone adhesive materials provided in Comparative Application Examples 1-3 is lower. Although the silicone adhesive material provided in Comparative Application Example 4 has higher adhesive strength, its adhesive strength does not decrease after irradiation. The elongation at break of the silicone adhesive material provided in Comparative Application Example 5 is significantly reduced.

[0133] The bonding between the silicone adhesive material and the substrate provided in Example 1 of this invention, and the schematic diagram of the mechanism for reducing adhesive force based on photoresponse, are shown below. Figure 1 As shown.

[0134] The applicant declares that this invention illustrates the photoresponsive tackifier, its preparation method, and its application through the above embodiments. However, this invention is not limited to the above embodiments, meaning that this invention does not necessarily rely on the above embodiments for implementation. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of the raw materials used in this invention, addition of auxiliary components, and selection of specific methods all fall within the protection and disclosure scope of this invention.

Claims

1. A photoresponsive tackifier, characterized by, The structure general formula of the light response tackifier is A-B-C, wherein A is an active vinyl end group that can participate in polymerization, B is a light response group, and C is a siloxane group or a silane coupling end group.

2. The photoresponsive tackifier of claim 1, wherein The A is selected from CH2=CH-, CH2=CR-, CH2=CH-CH2-O-, CH2=CH-Ph-O-, Any one of them, wherein R is a C4 to C8 alkyl group.

3. The photoresponsive tackifier of claim 1 or 2, wherein The B is a light response group compatible with a catalyst; Preferably, the B is a light response group compatible with a platinum catalyst; Preferably, the B is selected from any one of o-nitrobenzyl, azobenzene, benzoylmethyl.

4. The photoresponsive tackifier of any one of claims 1-3, wherein The C is selected from any one of trimethoxysilane, triethoxysilane, methyldiethoxysilane.

5. A method for preparing the photoresponsive tackifier according to any one of claims 1 to 4, characterized in that, The preparation method comprises the following steps: (1) mixing a photosensitive monomer, triethylamine, and an organic solvent, cooling in an ice water bath, then adding an inhibitor and a terminal vinyl-containing monomer, after the addition is completed, removing the ice water bath, continuing to react, and post-treating to obtain a first intermediate product; (2) mixing the first intermediate product, a siloxane monomer and / or a silane coupling agent, and an organic solvent, then adding a catalyst for the first time, reacting, supplementing the catalyst during the reaction, and post-treating to obtain a second intermediate product; (3) mixing the second intermediate product, vinyl boronic acid pinacol ester, a palladium catalyst, a sodium carbonate aqueous solution, and an organic solvent, reacting, and post-treating to obtain the light response tackifier.

6. The production method according to claim 5, wherein The photosensitive monomer in step (1) comprises any one or a combination of at least two of p-chloro-o-nitrobenzyl alcohol, 4-hydroxy-4'-bromoazobenzene, and 4'-hydroxy-4-bromobenzophenone; Preferably, the molar ratio of the photosensitive monomer to triethylamine in step (1) is 1:(0.8-1.2); Preferably, the organic solvent in step (1) comprises anhydrous dichloromethane; Preferably, the temperature of the ice water bath in step (1) is 0-10°C, preferably 0-5°C; Preferably, the inhibitor in step (1) comprises hydroquinone; Preferably, the amount of the inhibitor in step (1) is 0.1%-1%, preferably 0.1%-0.3%, of the mass of the photosensitive monomer; Preferably, the terminal vinyl-containing monomer in step (1) comprises any one or a combination of at least two of acryloyl chloride, methacryloyl chloride, acetyl chloride, allyl chloride, and p-chloromethylstyrene; Preferably, the molar ratio of the photosensitive monomer to the terminal vinyl-containing monomer in step (1) is 1:(1-1.2), preferably 1:(1-1.1); Preferably, the addition time of the terminal vinyl-containing monomer in step (1) is controlled to be 2-3h; Preferably, the total reaction time in step (1) is 10-12h, preferably 11-12h; Preferably, the post-treatment in step (1) comprises washing and drying.

7. The production method according to claim 5 or 6, characterized by, The siloxane monomer and / or the silane coupling agent in step (2) comprises any one or a combination of at least two of trimethoxysilane, triethoxysilane, and methyldiethoxysilane; Preferably, the molar ratio of the first intermediate product to the siloxane monomer and / or the silane coupling agent in step (2) is 1:(1.2-1.5); Preferably, the organic solvent in step (2) comprises anhydrous toluene; Preferably, the catalyst in step (2) comprises karstedt catalyst; Preferably, the amount of the first catalyst added in step (2) is 10-20 ppm of the total mass of the first intermediate product, the siloxane monomer and / or the silane coupling agent; Preferably, the temperature of the reaction in step (2) is 60-80°C, preferably 70-80°C; Preferably, the time of the reaction in step (2) is 8-10 h, preferably 8-9 h; Preferably, the catalyst is added during the reaction in step (2), specifically including: the catalyst is added every 2 h, and the amount of the catalyst added each time is 3-5 ppm of the total mass of the first intermediate product, the siloxane monomer and / or the silane coupling agent; Preferably, step (2) is carried out under inert gas protection; Preferably, the post-treatment in step (2) includes rotary evaporation under reduced pressure.

8. The production method according to any one of claims 5 to 7, characterized by, The molar ratio of the second intermediate product to pinacol vinyl boronate in step (3) is 1:(1-1.3), preferably 1:(1.1-1.2); Preferably, the amount of the palladium catalyst used in step (3) is 0.1%-1% of the sum of the mass of the second intermediate product and the pinacol vinyl boronate; Preferably, the amount of the aqueous sodium carbonate solution used in step (3) is such that the pH value of the system is 9-10; Preferably, the organic solvent in step (3) includes toluene and / or ethanol; Preferably, the temperature of the reaction in step (3) is 70-90°C, preferably 70-80°C; Preferably, the time of the reaction in step (3) is 12-24 h, preferably 12-16 h; Preferably, step (3) is carried out under inert gas protection; Preferably, the post-treatment in step (3) includes liquid separation, extraction, washing and drying.

9. A photosensitive silicone adhesive material, characterized by comprising: a silicone resin having a reactive group; a photopolymerization initiator; and a photopolymerization inhibitor. The raw materials for preparing the photosensitive silicone adhesive material include a vinyl silicone oil, a hydrogen-containing silicone oil, an adhesion promoter, a catalyst and an inhibitor, and the adhesion promoter includes the light-responsive adhesion promoter according to any one of claims 1-4 or prepared according to the preparation method in any one of claims 5-8; Preferably, the molar ratio of the vinyl groups in the vinyl silicone oil to the silicon-hydrogen groups in the hydrogen-containing silicone oil is 1:(1-1.2); Preferably, the amount of the adhesion promoter is 3%-10%, preferably 5%-10%, of the sum of the mass of the vinyl silicone oil and the hydrogen-containing silicone oil; Preferably, the amount of the catalyst is 5-20 ppm of the sum of the mass of the vinyl silicone oil and the hydrogen-containing silicone oil; Preferably, the amount of the inhibitor is 1-4 ppm of the sum of the mass of the vinyl silicone oil and the hydrogen-containing silicone oil.

10. A method for producing the photosensitive silicone adhesive material according to claim 9, characterized by, The preparation method includes the following steps: The adhesion promoter is mixed with the vinyl silicone oil, then the catalyst and the inhibitor are added, and second mixing is carried out, then the hydrogen-containing silicone oil is added, and third mixing is carried out, to obtain the photosensitive silicone adhesive material; Preferably, the rotation speed of the second mixing is 800-1500 rpm, preferably 800-1000 rpm; Preferably, the time of the second mixing is 8-24 h, preferably 8-12 h; Preferably, the rotation speed of the third mixing is 300-500 rpm, preferably 300 rpm; Preferably, the time of the third mixing is 8-12 h, preferably 10-12 h; Preferably, the temperature of the control system during the third mixing is lower than 35°C. Preferably, the third mixing is followed by a filtration step.

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