High-humidity-resistant non-yellowing acrylic pressure-sensitive adhesive material as well as preparation method and application thereof

Abstract

The invention discloses a high-humidity-resistant non-yellowing acrylic pressure-sensitive adhesive material as well as a preparation method and application thereof, and the preparation method comprises the following steps: pre-polymerizing a hydrophobic alkyl acrylate monomer, a fluorine-containing or silicon-containing functional monomer and an initiator to form an oligomer emulsion; adding an antioxidant, an ultraviolet absorbent, a self-assembly type chelating agent, modified zinc oxide nanoparticles and a pH response type buffering agent into the emulsion; staged polymerization is carried out under the synergistic effect of a microwave field and a pulsed magnetic field, a dynamic synergistic barrier network is formed through induction, and the pH value of the system is controllably reduced in the process; and carrying out post-treatment to obtain a glue solution, and coating to form a film. The pressure-sensitive adhesive material obtained by the invention can still keep excellent adhesive property, stability, high light transmittance and low color change characteristics for a long time after being tested in a high-temperature and high-humidity environment, effectively solves the technical problems of adhesive property degradation and yellowing in the high-humidity environment, and is particularly suitable for the fields with extremely high reliability requirements, such as optical adhesive tapes and electronic component adhesion.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pressure-sensitive adhesive, in particular to a high-humidity-resistant non-yellowing acrylic pressure-sensitive adhesive material, a preparation method and application thereof. BACKGROUND

[0002] Acrylate pressure-sensitive adhesive is widely used in optical film, electronic component bonding, medical device bonding and other fields due to its excellent adhesion, cohesive strength, aging resistance and optical transparency. However, the performance stability and appearance retention of traditional acrylic pressure-sensitive adhesive face severe challenges when used in harsh environments such as high temperature and high humidity (e.g. 85℃, 85% relative humidity) for a long time.

[0003] Firstly, the bonding performance decay in high-humidity environment is one of the main problems. The crosslinked network density of conventional acrylic pressure-sensitive adhesive is insufficient, which is difficult to effectively block the penetration of water vapor and oxygen. Under the condition of heat and humidity, water easily penetrates into the interior of the adhesive layer and the interface between the adhesive layer and the substrate, which destroys the interfacial bonding force, resulting in a significant decrease in the bonding performance (such as 180° peel strength) of the pressure-sensitive adhesive, which cannot meet the long-term reliability requirements.

[0004] Secondly, the adhesive layer is prone to yellowing, which affects the appearance and optical performance of the product. In order to prevent oxidative degradation, stabilizers such as hindered phenolic antioxidants and benzotriazole ultraviolet absorbers are usually added in the formula. However, in the traditional gel network, these stabilizers lack effective fixation mechanism, and are prone to migration, volatilization or extraction under the action of heat, humidity and external force, resulting in a decrease in their concentration in local areas and failure. The unprotected adhesive layer undergoes oxidative reaction under the combined action of heat and humidity and oxygen, generates chromophores, causes obvious yellowing, and is accompanied by a decrease in light transmittance, which is a fatal defect in transparent optical applications.

[0005] In the prior art, although attempts have been made to improve performance by adding inorganic nanoparticles (such as silicon dioxide) or adjusting the monomer ratio, but often only mechanical strength or hydrophobicity can be improved, and the complex problem of "moisture barrier-stabilizer locking-structural stability" cannot be systematically solved. For example, single nano-filler is difficult to form a dense and stable barrier network in the polymer matrix in the absence of specific interfacial action and energy field induction; and the conventional polymerization process cannot realize the directional grafting of functional monomers and the effective anchoring of stabilizer molecules.

[0006] To solve the above problems, the application provides a high-humidity-resistant non-yellowing acrylic pressure-sensitive adhesive material and a preparation method and application thereof, a dynamic synergistic barrier network generated by microwave-magnetic field synergistic polymerization is constructed, hydrophobic / oleophobic monomers are grafted, nanoparticles are energy focused, stabilizers are chelated and locked, and pH response densification is achieved, so that various mechanisms are organically combined to realize the synergistic improvement of long-term stability of bonding performance, high light transmittance and low color difference of the adhesive layer in a high-humidity environment. SUMMARY

[0007] The application aims to provide a high-humidity-resistant non-yellowing acrylic pressure-sensitive adhesive material and a preparation method and application thereof, so as to realize the synergistic improvement of long-term stability of bonding performance, high light transmittance and low color difference of the adhesive layer in a high-humidity environment.

[0008] The application is achieved by the following technical solutions. A high-humidity-resistant non-yellowing acrylic pressure-sensitive adhesive material, by weight, comprises: 50-70 parts of hydrophobic alkyl acrylate monomer, 10-20 parts of fluorine-containing or silicon functional monomer, 1-3 parts of antioxidant, 0.5-2 parts of ultraviolet absorber, 5-15 parts of modified zinc oxide nanoparticles, 1-2 parts of self-assembled chelating agent, and 0.5-1 part of pH-responsive buffer. The hydrophobic alkyl acrylate monomer is selected from isooctyl acrylate or 2-ethylhexyl acrylate; the fluorine-containing or silicon functional monomer is selected from perfluorobutyl acrylate or vinyl trimethoxysilane; the antioxidant is pentaerythritol tetra(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate); the ultraviolet absorber is 2-(2'-hydroxy-5'-methylphenyl)benzotriazole; the modified zinc oxide nanoparticles have a particle size of 10-50 nm and are modified on the surface by silane coupling agent KH-570; the self-assembled chelating agent is an ethylenediaminetetraacetic acid disodium derivative; the pH-responsive buffer is a citric acid-sodium citrate system; and the adhesive material forms a dynamic synergistic barrier network through microwave-magnetic field synergistic polymerization.

[0009] Preferably, the particle size of the modified zinc oxide nanoparticles is 20-40 nm, and the modification mass ratio of silane coupling agent KH-570 is 1-3%.

[0010] The application also claims a preparation method of the above high-humidity-resistant non-yellowing acrylic pressure-sensitive adhesive material, comprising the following steps: S1, premixing and preliminary polymerization: under the protection of a nitrogen flow rate of 0.5-1 L / min, the hydrophobic alkyl acrylate monomer, the fluorine-containing or silicon functional monomer, and the initiator are mixed, heated to 50-60°C, stirred at a speed of 200-300 rpm, and reacted for 30-40 minutes to form an oligomer emulsion; S2, adding stabilizers and nanoparticles: adding antioxidants, ultraviolet absorbers, and self-assembled chelating agents to the oligomer emulsion, stirring for 10-15 minutes, then adding modified zinc oxide nanoparticle dispersion and pH-responsive buffer, and adjusting the initial pH to 6.5±0.2; S3, microwave-magnetic field synergistic polymerization: under microwave power of 300-500 W, frequency of 2.45 GHz, and pulsed magnetic field intensity of 0.1-0.5 T, frequency of 10-50 Hz, the reaction is carried out in stages: initial stage of 10-15 minutes, microwave power of 300-400 W, magnetic field frequency of 10-20 Hz; subsequent stage of 5-10 minutes, microwave power of 400-500 W, magnetic field frequency of 20-50 Hz, and pH reduced to 5.5±0.2; S4, post-treatment and purification: cooling to 25-30°C, distillation under vacuum of 0.01-0.02 MPa for 15-20 minutes, centrifugation at 4000-6000 rpm for 5-8 minutes to obtain a glue solution; S5, coating and film formation: coating the glue solution on a substrate, controlling the glue layer thickness to be 20-50 μm, and drying at 80-100°C for 8-12 minutes.

[0011] Preferably, the initiator is a redox system with a mass ratio of potassium persulfate to sodium bisulfite of 1:1; the modified zinc oxide nanoparticle dispersion is prepared by ultrasonic dispersion of modified zinc oxide nanoparticles in ethyl acetate, with an ultrasonic power of 100-200 W, a frequency of 40 kHz, and a time of 10-15 minutes.

[0012] Preferably, in step S3, the microwave-magnetic field synergistic polymerization promotes the preferential grafting of the fluorine-containing or silicon-functional monomers to form a high-density chemical bond network, with the modified zinc oxide nanoparticles as energy focusing points, and the pulsed magnetic field intensity is 0.2-0.4 T, with the frequency being 15-20 Hz in the initial stage and 30-50 Hz in the subsequent stage.

[0013] Preferably, in step S3, the self-assembled chelating agent forms a complex layer under a pulsed magnetic field frequency of 20-50 Hz and a microwave power of 400-500 W, locking the antioxidants and ultraviolet absorbers in the gaps of the dynamic synergistic barrier network, and enhancing the barrier ability of the dynamic synergistic barrier network to moisture through the complex layer.

[0014] Preferably, in step S3, the pH-responsive buffer releases H⁺ through a citric acid-sodium citrate system during the process of reducing the pH from 6.5±0.2 to 5.5±0.2, inducing the dynamic synergistic barrier network to form a gradient density distribution, which enables the network to have self-adaptive recovery ability under humid heat conditions.

[0015] Preferably, in step S2, the dropping speed of the modified zinc oxide nanoparticle dispersion is 0.5-0.8 mL / min, and the ultrasonic dispersion time is 12-15 minutes, so as to ensure uniform dispersion of the modified zinc oxide nanoparticles in the oligomer emulsion.

[0016] The application also claims to protect the use of the above-mentioned high-humidity-resistant non-yellowing acrylic pressure-sensitive adhesive material in the preparation of optical adhesive tape, electronic component bonding or medical device adhesion, characterized in that the adhesive material is coated on a polyethylene terephthalate substrate, and the adhesive layer has a thickness of 20-40 μm.

[0017] Preferably, the optical adhesive tape is used for display screen adhesion in a high-humidity environment, and the dynamic synergistic barrier network maintains the transparency and adhesive properties of the adhesive layer in a relative humidity of 80-90% through the energy focusing point of the modified zinc oxide nanoparticles and the complex layer of the self-assembled chelating agent.

[0018] The core working mechanism of the application is to guide the construction of a dynamic, multi-level synergistic barrier network by the microwave-magnetic field synergistic polymerization process. Specifically, during the polymerization process, the modified zinc oxide nanoparticles act as energy focusing points and are selectively activated under the coupling action of the microwave field and the pulsed magnetic field, greatly promoting the preferential grafting and directional arrangement of fluorine-containing or silicon functional monomers on the polymer chain, thereby constructing a first dense chemical crosslinking network that is hydrophobic and oleophobic at the molecular level, effectively blocking the initial penetration of external moisture and oxygen. At the same time, the self-assembled chelating agent forms a stable "complex layer" under the driving of a specific pulsed magnetic field frequency and microwave power through molecular self-assembly behavior. This structure acts like a molecular cage, firmly locking small molecule stabilizers such as antioxidants and ultraviolet absorbers in the gaps of the polymer network, fundamentally solving the problem of stabilizer failure due to migration and volatilization, and giving the adhesive layer long-lasting anti-yellowing ability. In addition, the pH-responsive buffer introduced into the system creates a dynamic change from weak acidity (pH 6.5) to acidity (pH 5.5) during the reaction process. This pH gradient cleverly induces the polymer network to form a gradient density distribution from loose to dense; this gradient structure enables the adhesive layer to have a self-adaptive recovery ability similar to "shape memory" when facing external stress, and can buffer and disperse stress through elastic deformation of the microstructure, thereby maintaining the long-term stability of the structural integrity and adhesive reliability of the adhesive layer in harsh environments. In summary, the "dynamic synergistic barrier network" achieves an integrated solution to the three technical problems of moisture barrier, stabilizer fixation and structural stability through the synergistic mechanisms of energy field-induced graft polymerization, self-assembly locking and pH-responsive densification.

[0019] Thanks to the above technical solutions, the application has the following beneficial effects compared with the prior art: 1、The application fundamentally solves the performance attenuation problem of acrylic pressure-sensitive adhesive in high-humidity environment by constructing a unique "dynamic synergistic barrier network", which combines the inherent hydrophobicity of fluorine / silicon-containing monomers, the dense structure enhanced by nanoparticles, and the gradient density induced by pH response, effectively blocking the penetration of water vapor and oxygen; 2、The application has excellent anti-yellowing ability and optical stability, and introduces a "self-assembled chelating agent" to form a "complex layer" under the action of an energy field, which firmly locks antioxidants and ultraviolet absorbers in the gaps of the polymer network, effectively preventing the failure of stabilizers due to migration and volatilization; This mechanism makes the color difference (ΔE≤1.0) change very little after long-term humid heat aging, and the yellowing is almost invisible to the naked eye, while the light transmittance always remains above 91.5%, perfectly meeting the stringent requirements of appearance and light transmittance for display screens, optical films and other applications; 3、The application uses "pH-responsive buffer" to create a dynamic pH change environment during polymerization, inducing the polymer network to form a "gradient density distribution" from loose to dense; This structure allows the adhesive layer to adjust its microstructure when subjected to humid heat stress, exhibiting a certain "self-adaptive recovery ability", thereby better releasing internal stress and maintaining the overall structural integrity and durability of the adhesive layer, avoiding cracking or debonding caused by repeated swelling and shrinking; 4、The "microwave-magnetic field synergistic polymerization" process used in the application is an advanced green preparation technology, microwave can achieve rapid and uniform heating at the molecular level, and the "energy focusing point" effect of pulsed magnetic field and modified zinc oxide nanoparticles synergizes, greatly improving the grafting efficiency and reaction rate of monomers, reducing the polymerization time from several hours to tens of minutes; This not only significantly improves production efficiency and reduces energy consumption, but also effectively reduces by-products caused by incomplete reaction or local overheating, ensuring high purity and consistency of the product, with a polymerization yield of more than 95%; 5、The application is not a simple stacking of multiple components, but through ingenious formula design and innovative preparation process, it realizes the deep integration and synergistic effect of "hydrophobic barrier", "stabilizer fixation" and "structure enhancement"; The pressure-sensitive adhesive material obtained finally has high bonding strength, excellent weather resistance, outstanding optical performance and high reliability, and its comprehensive performance far exceeds that of traditional products, greatly expanding its application prospects in high-end optical adhesive tape, precision electronic component bonding, medical devices and other fields. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the specific embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or prior art description. Obviously, some of the drawings described below are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0021] Figure 1 is a flow chart of the preparation method of the pressure-sensitive adhesive material of embodiment 1 of the present application. DETAILED DESCRIPTION

[0022] In order to have a clearer understanding of the technical features, objectives and effects of the present application, the specific embodiments will be described in detail.

[0023] The present application will be further described below in combination with embodiments, but the present application is not limited to the following embodiments. The implementation conditions used in the embodiments can be further adjusted according to different requirements of specific use, and the implementation conditions indicated are the conventional conditions in the industry. The technical features involved in each embodiment of the present application can be combined with each other as long as there is no conflict between them.

[0024] The raw materials and equipment used in the present application are as follows, but it should be understood that these are not limitations of the present application, and those skilled in the art can select equivalent raw materials and equipment according to the situation.

[0025] Main raw materials and reagents: main monomer: isooctyl acrylate (CAS No.: 29590-42-9, purity ≥ 99%), 2-ethylhexyl acrylate (CAS No.: 103-11-7, purity ≥ 99%); Functional monomer: perfluorobutyl acrylate (CAS No.: 52591-27-2, purity ≥ 98%), vinyltrimethoxysilane (CAS No.: 2768-02-7, purity ≥ 98%).

[0026] Auxiliary agent: antioxidant: pentaerythritol tetra(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) (CAS No.: 6683-19-8, purity ≥ 98%); Ultraviolet absorber: 2-(2'-hydroxy-5'-methylphenyl) benzotriazole (UV-326, CAS No.: 3896-11-5, purity ≥ 99%); Self-assembled chelating agent: disodium ethylenediaminetetraacetate derivative (CAS No.: 6381-92-6, purity ≥ 99%); pH-responsive buffer: a buffer system composed of citric acid (CAS No.: 77-92-9, purity ≥ 99.5%) and sodium citrate (CAS No.: 6132-04-3, purity ≥ 99%).

[0027] Nanomaterial: modified zinc oxide nanoparticles with a particle size range of 10-50 nm, the surface of which is modified by silane coupling agent KH-570 (CAS No.: 2530-85-0), and the modified mass fraction is 1-3%.

[0028] Initiating system: a redox initiating system composed of potassium persulfate (CAS No.: 7727-21-1, purity ≥ 99%) and sodium bisulfite (CAS No.: 7631-90-5, purity ≥ 99%) at a mass ratio of 1:1.

[0029] Solvent: ethyl acetate (CAS No.: 141-78-6, purity ≥ 99.5%), deionized water (conductivity < 0.1 μS / cm).

[0030] Main instruments and equipment: the main equipment used in the preparation process of the present application includes but is not limited to: a conventional four-necked flask reactor equipped with a mechanical stirrer, a thermometer and a nitrogen protection device; a microwave chemical reactor with adjustable power and frequency; a magnetic field generator capable of generating a pulsed magnetic field; an ultrasonic disperser; a vacuum distillation device; a high-speed centrifuge; a precision coater for coating; a circulating air oven.

[0031] Example 1 Referring to the accompanying Figure 1 , the present embodiment provides a preparation method of a high-humidity-resistant non-yellowing acrylic pressure-sensitive adhesive material, comprising the following steps: S1, premixing and preliminary polymerization: in a 500 mL four-necked flask equipped with a nitrogen protection device and a mechanical stirrer, nitrogen is introduced (flow rate 0.8 L / min); 60 parts by weight of isooctyl acrylate, 15 parts by weight of perfluorobutyl acrylate, 0.4 parts by weight of potassium persulfate and 0.4 parts by weight of sodium bisulfite are added; the temperature is raised to 55°C, and the reaction is carried out at a stirring speed of 250 rpm for 35 minutes to form an oligomer emulsion; S2, adding stabilizer and nanoparticles: 2 parts by weight of antioxidant 1010, 1 part by weight of ultraviolet absorber UV-326 and 1.5 parts by weight of ethylenediaminetetraacetic acid disodium salt derivative are added to the oligomer emulsion obtained in step S1, and stirred at 350 rpm for 12 minutes; then, 10 parts by weight of modified zinc oxide nanoparticles (particle size 20 nm, KH-570 modification ratio 2%) are ultrasonically dispersed in 25 parts by weight of ethyl acetate to prepare a dispersion liquid, which is added dropwise to the emulsion at a rate of 0.6 mL / min, while 0.8 parts by weight of citric acid-sodium citrate buffer is added, and the initial pH value of the system is adjusted to 6.5; S3, microwave-magnetic field synergistic polymerization: the mixture obtained in step S2 is transferred to a microwave reactor, and a pulsed magnetic field with a strength of 0.3 T is applied; initial stage reaction for 12 minutes: microwave power 350 W, magnetic field frequency 15 Hz; subsequent stage reaction for 8 minutes: microwave power 450 W, magnetic field frequency 40 Hz; at the end of the reaction, the pH of the system is reduced to 5.5; this process maintains a nitrogen flow rate of 0.4 L / min and a stirring speed of 150 rpm; S4, post-treatment and purification: the product obtained in step S3 is cooled to 28°C, and distilled under a vacuum degree of 0.015 MPa for 18 minutes; then centrifuged at a centrifugal speed of 5000 rpm for 6 minutes to obtain a pure glue liquid; S5, coating and film formation: the glue liquid obtained in step S4 is coated on a polyethylene terephthalate (PET) substrate, with a glue layer thickness of 30 μm, and dried at 90°C for 10 minutes to obtain the high-humidity-resistant non-yellowing acrylic pressure-sensitive adhesive material.

[0032] Example 2 The present embodiment provides a preparation method of a high-humidity-resistant non-yellowing acrylic pressure-sensitive adhesive material, comprising the following steps: S1, premixing and initial polymerization: 50 parts by weight of isooctyl acrylate, 20 parts by weight of vinyltrimethoxysilane, 0.3 parts by weight of potassium persulfate, and 0.3 parts by weight of sodium bisulfite are added to a reactor under a nitrogen flow rate of 0.8 L / min; the temperature is raised to 50°C, and the reaction is stirred at 200 rpm for 40 minutes to form an oligomer emulsion; S2, addition of stabilizer and nanoparticles: 1 part by weight of antioxidant 1010, 0.5 parts by weight of UV-326, and 1 part by weight of disodium ethylenediaminetetraacetate derivative are added to the oligomer emulsion obtained in step S1 and stirred; 5 parts by weight of modified zinc oxide nanoparticles (particle size 20 nm, modified with KH-570 at a proportion of 1%) are ultrasonically dispersed, and then added dropwise at a rate of 0.5 mL / min, while 0.5 parts by weight of a pH-responsive buffer is added to adjust the initial pH to 6.5; S3, microwave-magnetic field synergistic polymerization: the mixture obtained in step S2 is transferred to a microwave reactor, and a pulsed magnetic field with a strength of 0.3 T is applied; initial stage reaction for 12 minutes: microwave power 350 W, magnetic field frequency 15 Hz; subsequent stage reaction for 8 minutes: microwave power 450 W, magnetic field frequency 40 Hz; at the end of the reaction, the pH of the system is reduced to 5.5; this process maintains a nitrogen flow rate of 0.4 L / min and a stirring speed of 150 rpm; S4, post-treatment and purification: the product obtained in step S3 is cooled to 28°C, and distilled under a vacuum degree of 0.015 MPa for 18 minutes; then centrifuged at a centrifugal speed of 5000 rpm for 6 minutes to obtain a pure glue liquid; S5, coating and film forming: the glue solution obtained in step S4 is coated on the PET substrate, the glue layer thickness is controlled to be 20 pm, and the glue is dried at 80°C for 12 minutes to obtain the high-humidity-resistant and yellowing-resistant acrylic pressure-sensitive adhesive material.

[0033] Example 3 The embodiment provides a preparation method of a high-humidity-resistant and yellowing-resistant acrylic pressure-sensitive adhesive material, and comprises the following steps: S1, premixing and preliminary polymerization: 70 parts by weight of 2-ethylhexyl acrylate, 10 parts by weight of perfluorobutyl acrylate, 0.5 parts by weight of potassium persulfate and 0.5 parts by weight of sodium bisulfite are added to a reactor under a nitrogen flow rate of 1 L / min; the temperature is increased to 60°C, and the reaction is stirred at 300 rpm for 30 minutes to form an oligomer emulsion; S2, adding stabilizers and nanoparticles: 3 parts by weight of antioxidant 1010, 2 parts by weight of UV-326 and 2 parts by weight of disodium ethylenediaminetetraacetate derivative are added to the oligomer emulsion obtained in step S1 and stirred and mixed; 15 parts by weight of modified zinc oxide nanoparticles (particle size 40 nm, KH-570 modification ratio 3%) are ultrasonically dispersed, then added dropwise at a rate of 0.8 mL / min, and 1 part by weight of a pH-responsive buffer is added at the same time to adjust the initial pH to 6.5; S3, microwave-magnetic field synergistic polymerization: the mixture obtained in step S2 is transferred to a microwave reactor, a pulsed magnetic field with a strength of 0.3 T is applied, the initial stage is 10 minutes: microwave power 400 W, magnetic field frequency 20 Hz; the subsequent stage is 5 minutes: microwave power 500 W, magnetic field frequency 50 Hz; and the pH is reduced to 5.5 at the end of the reaction; S4, post-treatment and purification: the product obtained in step S3 is cooled to 28°C, distilled under a vacuum degree of 0.02 MPa, and then centrifuged at 6000 rpm for 5 minutes to obtain a glue solution; S5, coating and film forming: the glue solution obtained in step S4 is coated on the PET substrate, the glue layer thickness is controlled to be 20 pm, and the glue is dried at 80°C for 12 minutes to obtain the high-humidity-resistant and yellowing-resistant acrylic pressure-sensitive adhesive material.

[0034] Example 4 The embodiment is based on the above-described example 1, and the same parts as the above-described example 1 are not described. In the embodiment, the modified zinc oxide nanoparticles used in step S2 are 8 parts by weight, the particle size is 20 nm, and the KH-570 modification mass ratio is 1%; the remaining steps and parameters are the same as those in example 1.

[0035] Example 5 The embodiment is based on the above-described example 1, and the same parts as the above-described example 1 are not described.

[0036] In this embodiment: the pulse magnetic field strength used in step S3 is 0.2 T, the initial frequency is 15 Hz, and the subsequent stage frequency is 30 Hz; the remaining steps and parameters are exactly the same as in Example 1.

[0037] Example 6

[0038] This example is based on the above-mentioned Example 1, and the same parts as in Example 1 will not be repeated. In this embodiment: the amount of self-assembled chelating agent (disodium ethylenediaminetetraacetate derivative) used in step S2 is 2 parts by weight; in step S3, the microwave power in the subsequent stage is 400 W, and the magnetic field frequency is 30 Hz; the remaining steps and parameters are exactly the same as in Example 1.

[0039] Comparative Example 1 This comparative example is a preparation method of a traditional acrylic pressure-sensitive adhesive, which specifically includes the following steps: mixing 60 parts by weight of isooctyl acrylate, 5 parts by weight of acrylic acid, 2 parts by weight of antioxidant 1010, 1 part by weight of UV-326, 10 parts by weight of silicon dioxide (particle size 50 nm), and 0.5 parts by weight of potassium persulfate in a reactor; stirring and polymerizing at 80°C for 4 hours; no microwave-magnetic field synergy is used in this process, and no self-assembled chelating agent and pH-responsive buffer are added; after the reaction is completed, cooling and vacuum distillation are performed; the obtained adhesive solution is coated on a PET substrate, the adhesive layer thickness is controlled to be 30 μm, and drying is performed at 90°C for 10 minutes to obtain a comparative example sample.

[0040] Comparative Example 2 This comparative example is based on the above-mentioned Example 1, and the same parts as in Example 1 will not be repeated. In this comparative example: no modified zinc oxide nanoparticles are added in step S2; only microwave is used for reaction in step S3 (initial power 350 W, subsequent power 450 W), and no pulse magnetic field is applied; the remaining steps and parameters are exactly the same as in Example 1.

[0041] The products obtained in the above examples and comparative examples are subjected to performance testing, and the testing methods are as follows: Adhesion performance test: according to GB / T2792-2014, a tensile testing machine is used to test the 180° peeling strength; test conditions: initial performance (23°C, 50%RH); high humidity performance (85°C, 85%RH, after 168 hours).

[0042] Transparency test: according to GB / T2410-2008, a spectrophotometer is used to measure the adhesive layer light transmittance (550 nm); test conditions: initial light transmittance; high humidity light transmittance (85°C, 85%RH, after 168 hours).

[0043] Yellowing test: According to GB / T23983-2009, the color difference value ΔE (CIELab) was measured by color difference meter; test conditions: initial color difference; high humidity color difference (85°C, 85% RH, after 168 hours).

[0044] The adhesive materials obtained from Examples 1-6 and Comparative Examples 1-2 were coated on PET substrates (adhesive layer thickness 30 μm) and tested, and the test results are shown in Table 1.

[0045] Table 1 Test item Initial peel strength (N / 25 mm) High humidity peel strength (N / 25 mm) Initial light transmittance (%) High humidity light transmittance (%) Initial ΔE High humidity ΔE Example 1 12.5 12 92.5 91.8 0.3 0.8 Example 2 11.8 11.3 92 91.5 0.4 0.9 Example 3 13 12.4 93 92.2 0.2 0.7 Example 4 12.8 12.3 92.8 92 0.3 0.7 Example 5 12.7 12.2 92.6 91.9 0.3 0.7 Example 6 12.9 12.4 92.7 92.1 0.2 0.6 Comparative Example 1 10.5 7.8 90 85.5 0.5 3.2 Comparative Example 2 11 8.5 90.5 87 0.4 2.8

[0046] In combination with Examples 1-3 and Comparative Examples 1-2 and in combination with Table 1, the synergistic effect of the modified zinc oxide nanoparticles, microwave-magnetic field coupling, self-assembled chelating agent and pH-responsive buffer formed a dynamic synergistic barrier network, so that the adhesive material had a peel strength attenuation of less than 5% in a high humidity environment, a light transmittance maintained at more than 91.5%, and ΔE less than 1.0. Compared with Comparative Example 1, the peel strength of Examples 1-3 was improved by about 50%, the light transmittance was improved by about 7%, and ΔE was reduced by about 75%, indicating that the dynamic synergistic barrier network effectively blocked moisture and oxygen. Compared with Comparative Example 2, the performance of Example 1 was superior, indicating that the energy focusing point of the modified zinc oxide nanoparticles and the magnetic field coupling were crucial to the network density.

[0047] In combination with Example 4 and Example 1, when the modified zinc oxide nanoparticle particle size was 20 nm and the KH-570 modification ratio was 1%, the peel strength and light transmittance were slightly better, and ΔE was slightly lower, indicating that a smaller particle size and a lower modification ratio enhanced the energy focusing effect.

[0048] In combination with Example 5 and Example 1, when the magnetic field strength was 0.2 T and the frequency was 15-30 Hz, the performance was close to that of Example 1, indicating that parameter optimization further improved the grafting efficiency.

[0049] In combination with Example 6 and Example 1, when the self-assembled chelating agent dosage was 2 parts and the magnetic field frequency was 30 Hz, ΔE was the lowest, indicating that the complex layer enhanced the stabilizer locking effect.

[0050] In summary, the application fundamentally solves the problem of performance degradation of acrylic pressure-sensitive adhesive in high-humidity environment by constructing a unique "dynamic synergistic barrier network". The network combines the inherent hydrophobicity of fluorine / silicon-containing monomers, the dense structure enhanced by nanoparticles, and the gradient density induced by pH response, effectively blocking the penetration of water vapor and oxygen. Experimental data show that after 85°C, 85% relative humidity, and 168 hours of severe aging test, the 180° peel strength attenuation rate of the adhesive product is less than 5%, which is much better than traditional products (attenuation usually exceeds 25%), ensuring long-term bonding reliability in humid environments. The application has excellent anti-yellowing ability and optical stability. The application introduces a "self-assembled chelating agent" and forms a "complex layer" under the action of an energy field, like a molecular lock that firmly locks antioxidants and ultraviolet absorbers in the gaps of the polymer network, effectively preventing the failure of stabilizers due to migration and volatilization. This mechanism makes the color difference (ΔE≤1.0) of the adhesive layer change very little after long-term humid heat aging, and the yellowing is almost invisible to the naked eye. At the same time, the light transmittance always remains above 91.5%, perfectly meeting the stringent requirements of display screens, optical films, and other applications for appearance and light transmittance. The application uses "pH-responsive buffer" to create a dynamic pH change environment during polymerization, inducing the polymer network to form a "gradient density distribution" from loose to dense. This structure allows the adhesive layer to adjust its microstructure when subjected to humid heat stress, exhibiting certain "self-adaptive recovery ability", thereby better releasing internal stress and maintaining the overall structural integrity and durability of the adhesive layer, avoiding cracking or debonding caused by repeated swelling and shrinking. The "microwave-magnetic field synergistic polymerization" process used in the application is an advanced green preparation technology. Microwave can achieve rapid and uniform heating at the molecular level, while the "energy focusing point" effect of pulsed magnetic field and modified zinc oxide nanoparticles synergizes, greatly improving the grafting efficiency and reaction rate of monomers, reducing the polymerization time from several hours to several tens of minutes. This not only significantly improves production efficiency and reduces energy consumption, but also effectively reduces by-products caused by incomplete reaction or local overheating, ensuring high purity and consistency of the product, with a polymerization yield of more than 95%. The application is not a simple stacking of multiple components, but through sophisticated formula design and innovative preparation process, it realizes the deep integration and synergistic effect of "hydrophobic barrier", "stabilizer fixation", and "structure enhancement". The final pressure-sensitive adhesive material has high bonding strength, excellent weather resistance, outstanding optical performance, and high reliability, with comprehensive performance far superior to traditional products, greatly expanding its application prospects in high-end optical adhesive tape, precision electronic component bonding, medical devices, and other fields.

[0051] The above embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, several modifications and improvements can be made, which are within the scope of protection of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A high-humidity resistant, non-yellowing acrylic pressure-sensitive adhesive material, characterized in that, By weight, it includes: 50-70 parts of hydrophobic alkyl acrylate monomer, 10-20 parts of fluorine- or silicon-containing functional monomer, 1-3 parts of antioxidant, 0.5-2 parts of ultraviolet absorber, 5-15 parts of modified zinc oxide nanoparticles, 1-2 parts of self-assembled chelating agent, and 0.5-1 parts of pH-responsive buffer. The hydrophobic alkyl acrylate monomer is selected from isooctyl acrylate or 2-ethylhexyl acrylate; the fluorine-containing or silicon-containing functional monomer is selected from perfluorobutyl acrylate or vinyltrimethoxysilane; the antioxidant is pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate); the ultraviolet absorber is 2-(2'-hydroxy-5'-methylphenyl)benzotriazole; the modified zinc oxide nanoparticles have a particle size of 10-50 nm and their surface is modified with silane coupling agent KH-570; the self-assembling chelating agent is a disodium ethylenediaminetetraacetate derivative; the pH-responsive buffer is a citric acid-sodium citrate system; and the adhesive material forms a dynamic synergistic barrier network through microwave-magnetic field synergistic polymerization.

2. The high-humidity resistant, non-yellowing acrylic pressure-sensitive adhesive material according to claim 1, characterized in that, The modified zinc oxide nanoparticles have a particle size of 20-40 nm, and the mass ratio of silane coupling agent KH-570 modification is 1-3%.

3. A method for preparing a high-humidity resistant, non-yellowing acrylic pressure-sensitive adhesive material as described in any one of claims 1 to 2, characterized in that, Includes the following steps: S1. Premixing and preliminary polymerization: Under the protection of nitrogen flow rate of 0.5~1L / min, hydrophobic alkyl acrylate monomers, fluorine-containing or silicon functional monomers and initiators are mixed, heated to 50~60°C, stirred at 200~300rpm, and reacted for 30~40 minutes to form an oligomer emulsion. S2. Adding stabilizers and nanoparticles: Add antioxidants, UV absorbers, and self-assembling chelating agents to the oligomer emulsion, stir for 10-15 minutes, then add modified zinc oxide nanoparticle dispersion and pH-responsive buffer dropwise, adjusting the initial pH to 6.5±0.

2. S3, Microwave-Magnetic Field Synergistic Polymerization: Under microwave power of 300~500W, frequency of 2.45GHz and pulsed magnetic field strength of 0.1~0.5T, frequency of 10~50Hz, the reaction is carried out in stages: the initial stage is 10~15 minutes, microwave power is 300~400W, and magnetic field frequency is 10~20Hz; the subsequent stage is 5~10 minutes, microwave power is 400~500W, magnetic field frequency is 20~50Hz, and the pH drops to 5.5±0.

2. S4. Post-treatment and purification: Cool to 25~30°C, distill under vacuum of 0.01~0.02MPa for 15~20 minutes, and centrifuge at 4000~6000rpm for 5~8 minutes to obtain the gel solution; S5. Coating and film formation: Coat the adhesive solution onto the substrate, control the adhesive layer thickness to be 20~50μm, and dry at 80~100°C for 8~12 minutes.

4. The preparation method of the high humidity resistant and non-yellowing acrylic pressure-sensitive adhesive material according to claim 3, characterized in that, The initiator is a redox system of potassium persulfate and sodium bisulfite in a mass ratio of 1:1; the modified zinc oxide nanoparticle dispersion is prepared by ultrasonically dispersing modified zinc oxide nanoparticles in ethyl acetate, with an ultrasonic power of 100~200W, a frequency of 40kHz, and a time of 10~15 minutes.

5. The preparation method of the high humidity resistant and non-yellowing acrylic pressure-sensitive adhesive material according to claim 3, characterized in that, In step S3, the microwave-magnetic field synergistic polymerization uses the modified zinc oxide nanoparticles as energy focusing points to promote the preferential grafting of fluorine- or silicon-containing functional monomers to form a high-density chemical bond network. The pulsed magnetic field strength is 0.2~0.4T, and the frequency is 15~20Hz in the initial stage and 30~50Hz in the subsequent stage.

6. The preparation method of the high humidity resistant and non-yellowing acrylic pressure-sensitive adhesive material according to claim 3, characterized in that, In step S3, the self-assembling chelating agent forms a complex layer under a pulsed magnetic field frequency of 20~50Hz and a microwave power of 400~500W, locking the antioxidant and ultraviolet absorber in the gaps of the dynamic synergistic barrier network.

7. The preparation method of the high humidity resistant and non-yellowing acrylic pressure-sensitive adhesive material according to claim 3, characterized in that, In step S3, the pH-responsive buffer releases H⁺ through the citric acid-sodium citrate system as the pH decreases from 6.5±0.2 to 5.5±0.2, inducing the dynamic synergistic barrier network to form a gradient density distribution.

8. The preparation method of the high humidity resistant and non-yellowing acrylic pressure-sensitive adhesive material according to claim 3, characterized in that, In step S2, the dropping rate of the modified zinc oxide nanoparticle dispersion is 0.5~0.8 mL / min, and the ultrasonic dispersion time is 12~15 minutes.

9. The application of a high-humidity resistant, non-yellowing acrylic pressure-sensitive adhesive material prepared by any one of claims 1-2 or any one of claims 3-8 in the preparation of optical tapes, electronic component bonding, or medical device bonding, characterized in that, The adhesive material is coated on a polyethylene terephthalate substrate, and the adhesive layer thickness is 20~40μm; the optical tape is used for display screen bonding in high humidity environments.

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