Anti-aging acrylic pressure-sensitive adhesive for TFT-LCD (Thin Film Transistor-Liquid Crystal Display) polaroid and preparation method thereof

Abstract

The invention discloses an acrylic pressure-sensitive adhesive for a TFT-LCD (Thin Film Transistor-Liquid Crystal Display) polaroid and a preparation method of the acrylic pressure-sensitive adhesive, and belongs to the field of pressure-sensitive adhesives for optical display. The pressure-sensitive adhesive is composed of an acrylate copolymer, an antistatic agent, an antioxidant, a silane coupling agent and a curing agent, wherein the side chain of the acrylate copolymer has alkyl, hydroxyl, carboxyl, alkylamino, acylamino and ethyoxyl structures; the solid content of the pressure-sensitive adhesive is 10-60%; wherein the weight-average molecular weight of the acrylate copolymer is 8 million to 2 million; the acrylate copolymer is a copolymer formed by polymerizing and copolymerizing an acrylate soft monomer, an acrylate hard monomer, a hydroxyl-containing acrylic monomer, a carboxyl-containing acrylic monomer, an acrylamide monomer and an ethyoxyl structure-containing acrylic monomer through a free radical solution. The acrylic pressure-sensitive adhesive disclosed by the invention has relatively low initial bonding force and a relatively excellent antistatic effect, and after accelerated aging, a polaroid prepared from the pressure-sensitive adhesive does not have a light leakage phenomenon caused by shrinkage, bubble rebound and edge warping phenomena.

Description

Technical Field

[0001] The present invention relates to the technical field of acrylic pressure-sensitive adhesives for optical displays, and particularly relates to an aging-resistant acrylic pressure-sensitive adhesive for TFT-LCD polarizers and a preparation method thereof. Background Art

[0002] Adhesives can be classified into thermosetting, hot-melt, room-temperature curing, pressure-sensitive types, etc. according to the application method. A pressure-sensitive adhesive is an adhesive that can form an effective bond with the adherend under the conditions of applying a small pressure and a short time and has no residual glue after peeling. Due to the inherent advantage of reworkability, pressure-sensitive adhesives have been widely used in various industries, including consumer electronics, advertising, packaging, safety protection, automotive, household appliances, medical and other industries. Thin-film transistor liquid crystal displays (TFT-LCDs) have the characteristics of being thin and light, having a high image resolution, low power consumption, and a long lifespan, and are thus widely used in televisions, computer displays, laptop computers, and mobile phones. The operating principle of TFT-LCD can be briefly described as using a polarizer to limit the direction of light propagation, and at the same time using a circuit to generate an electric field to drive liquid crystal molecules. The liquid crystal molecules have a deflecting effect on light, forming a switching function for light, and then matching with a color filter to obtain a color imaging effect. Therefore, one of the important components of TFT-LCD is the polarizer element, which is mainly composed of a polarizing film, a compensating film, and a pressure-sensitive adhesive. The polarizing film is mainly composed of oriented polyvinyl alcohol (PVA) and triacetyl cellulose (TAC). PVA plays a role in polarizing incident light, and TAC plays a role in protecting PVA. The polarizing film is assembled to both sides of the liquid crystal cell using a pressure-sensitive adhesive, and the polarization axes are perpendicular to each other.

[0003] One of the most serious problems of TFT-LCD is the "light leakage" phenomenon. Affected by the temperature gradient of the backlight source and the uneven distribution of thermal stress, under relatively dim light conditions, uneven or irregular light spot patterns are easily observed. Usually, it appears at the edges of twisted nematic (TN) displays or at the angular positions of vertical alignment (VA) displays. "Light leakage" will cause losses in display details and contrast. To obtain high polarization performance, the PVA film must have a large optical anisotropy, which can be achieved by stretching PVA multiple times during the processing. However, the stretched PVA molecules tend to relax to a random state when exposed to high temperature and high humidity conditions, resulting in the shrinkage of the polarizing film. The distortion of the polarization axis caused by shrinkage leads to a deviation in the cross-polarization between the upper and lower polarizing films, ultimately resulting in the light leakage phenomenon. In addition, the internal stress caused by shrinkage is easily accumulated in the pressure-sensitive adhesive layer between the polarizing film and the liquid crystal cell glass, which in turn causes the warping of the polarizing film and the generation of bubbles between the pressure-sensitive adhesive and the glass. Therefore, the pressure-sensitive adhesive for polarizing films should not only provide excellent adhesion performance but also have excellent high-temperature and high-humidity resistance and the characteristics of resisting "light leakage". To prevent the adverse effects of static electricity on the orientation of liquid crystal molecules during the assembly process of LCD panels, the pressure-sensitive adhesive for polarizing films should also have a small resistivity.

[0004] Currently, the pressure-sensitive adhesives for polarizing films sold on the market are basically products of Japanese and Korean companies. Although their performance is qualified, the product prices are relatively high. Although domestic pressure-sensitive adhesives for polarizing films have price advantages, there is still a certain gap in their performance compared with Japanese and Korean products, mainly reflected in the resistance to "light leakage" and antistatic performance.

[0005] Related literature reports show that a series of systematic studies have been carried out on the relationship between the stress relaxation performance of pressure-sensitive adhesives and the resistance to "light leakage", including adjusting the stress relaxation performance of pressure-sensitive adhesives by controlling the crosslinking density to study the influence of this process on the resistance to "light leakage" phenomenon (H. Chun, et al. J. Appl. Polym. Sci. 2007, 106, 2746); including studying the problem of preventing "light leakage" of pressure-sensitive adhesives by designing the glass transition temperature of polymers (M. S. Yang, et al. J. Macromol. Sci., Part A: Pure Appl. Chem. 2009, 46, 1142); including studying the anti-"light leakage" performance of pressure-sensitive adhesives by designing the polymer side chain structure (I. Nam, et al. Polym. Adv. Technol. 2012, 23, 1181). Chinese patents CN112708008B, CN104293249B, and CN110776592A show that the inventors use acrylate radical copolymerization technology to prepare pressure-sensitive adhesives for polarizers, or fine-tune the process on this basis to adjust the molecular weight and molecular weight distribution of polymers, but do not provide molecular weight and molecular weight distribution data, do not elaborate on the internal law between the structure of pressure-sensitive adhesives and the resistance to "light leakage", and do not mention the antistatic effect of pressure-sensitive adhesives. Chinese patents TWI274779B and TWI328029B disclose a method of adding an ester plasticizer, an alkali metal salt or a quaternary ammonium salt with one or more ether bonds to endow the pressure-sensitive adhesive for polarizers with antistatic effect, but for use scenarios with higher durability requirements (such as in-vehicle displays), small molecule plasticizers and alkali metal salts are likely to migrate outside the polymer system, causing durability problems such as bubbles and warping. Chinese patent TWI316531B discloses adding a low molecular weight copolymer (weight average molecular weight 2000 - 30000) to a high molecular weight copolymer (weight average molecular weight 1 million - 2 million) to adjust the balance of cohesion and stress relaxation ability, thereby solving the "light leakage" problem, but the preparation method of this polarizer pressure-sensitive adhesive is relatively cumbersome, requiring step-by-step synthesis of polymers with different molecular weights and then mixing operations.

[0006] Therefore, how to provide a pressure-sensitive adhesive with a simple synthesis method, excellent adhesion, resistance to damp heat aging and stress relaxation ability, and excellent resistance to "light leakage" and antistatic effect is a problem to be solved.

[0007] In view of this, the present invention is specifically proposed. Summary of the Invention

[0008] The object of the present invention is to provide an aging-resistant acrylic pressure-sensitive adhesive for TFT-LCD polarizers and its preparation method, which has excellent adhesion, resistance to damp heat aging and stress relaxation ability, and has excellent resistance to "light leakage" and antistatic effect, and the synthesis method is simple and the cost is low, so as to solve the above technical problems existing in the prior art.

[0009] The object of the present invention is achieved by the following technical solutions:

[0010] An aging-resistant acrylic pressure-sensitive adhesive for TFT-LCD polarizers, which is composed of an acrylate copolymer with alkyl, hydroxyl, carboxyl, alkylamino, amide and ethoxy structures in the side chain, an antistatic agent, an antioxidant, a silane coupling agent and a curing agent, and the solid content of the pressure-sensitive adhesive is 10% to 60%; wherein, the weight-average molecular weight of the acrylate copolymer is 800,000 to 2,000,000; the acrylate copolymer is a copolymer formed by free radical solution polymerization of acrylate soft monomers, acrylate hard monomers, hydroxyl-containing acrylic monomers, carboxyl-containing acrylic monomers, acrylamide monomers and ethoxy structure-containing acrylic monomers.

[0011] Preferably, in the above pressure-sensitive adhesive, in the acrylate copolymer, the weight fractions of the hydroxyl-containing acrylic monomer, the carboxyl-containing acrylic monomer, the acrylamide monomer, and the ethoxy structure-containing acrylic monomer in the total weight of all monomers are 0.01 to 20%, 0.01 to 10%, 0.01 to 20%, and 0.01 to 20%, respectively.

[0012] Preferably, in the above pressure-sensitive adhesive, the acrylate soft monomer is one or more of octadecyl acrylate, dodecyl acrylate, isooctyl acrylate, octyl acrylate, n-butyl acrylate, isobutyl acrylate, n-propyl acrylate, and ethyl acrylate;

[0013] The acrylate hard monomer is one or more of methyl acrylate, methyl methacrylate, acrylonitrile, styrene, isobutyl methacrylate, tert-butyl methacrylate, and vinyl acetate;

[0014] The carboxyl-containing acrylic monomer is one or more of acrylic acid, methacrylic acid, and itaconic acid;

[0015] The acrylamide monomer is one or more of N,N-dimethylaminopropyl acrylamide, N,N-dimethylaminopropyl methacrylamide, N,N-diethylaminopropyl acrylamide, N,N-diethylaminopropyl methacrylamide, N,N-dimethylacrylamide, N,N-diethylacrylamide, N-isopropylacrylamide, and acryloylmorpholine;

[0016] The acrylic monomer containing an ethoxy structure is one or more of ethoxyethoxyethyl acrylate, ethoxyethyl acrylate, ethoxymethoxyethyl acrylate, ethoxymethyl acrylate, and methoxyethyl acrylate.

[0017] Preferably, in the above-mentioned pressure-sensitive adhesive, the acrylate copolymer is copolymerized by radical solution stepwise polymerization in the following manner, including:

[0018] Add acrylate soft monomer, acrylate hard monomer, hydroxyl-containing acrylic monomer, carboxyl-containing acrylic monomer, acrylamide monomer, acrylic monomer containing an ethoxy structure, initiator, and solvent into the reaction kettle and dropping tank device respectively and mix evenly. Set the external temperature to 60-80°C. Under the N2 atmosphere, heat up. When the materials in the reaction kettle reflux and foam, start to uniformly drop the materials in the dropping tank, and carry out the reaction by means of stepwise radical solution polymerization. Record the reaction temperature, titration time, and the maximum value of the internal temperature at the initial stage of titration. After the dropping is completed, adjust the external temperature to 90-100°C and carry out the first heat preservation reaction for 0.5-2 hours. Then add the first post-initiator, and then carry out the second heat preservation reaction for 0.5-2 hours. Then add the second post-initiator, and then carry out the third heat preservation reaction for 0.5-2 hours. Then add the third post-initiator and carry out the heat preservation reaction for 0.5-3 hours. Cool down to below 40°C, add solvent for dilution, stir evenly, filter, and discharge. The obtained copolymer is the acrylate copolymer.

[0019] Preferably, in the above-mentioned pressure-sensitive adhesive, the solvent is one or more of ethyl acetate, methyl ethyl ketone, butyl acetate, methyl acetate, toluene, isopropyl alcohol, and methanol;

[0020] The initiator is one or more of azobisisobutyronitrile, azobisisoheptonitrile, azobisisopentanenitrile, benzoyl peroxide, tert-butyl peroxy-2-ethylhexanoate, and tert-amyl peroxy-2-ethylhexanoate.

[0021] Preferably, in the above-mentioned pressure-sensitive adhesive, the antistatic agent accounts for 0.01-10% of the total weight of all monomers in the acrylate copolymer;

[0022] The antioxidant accounts for 0.01-10% of the total weight of all monomers in the acrylate copolymer;

[0023] The silane coupling agent accounts for 0.0001-10% of the total weight of all monomers in the acrylate copolymer;

[0024] The curing agent accounts for 0.001-10% of the total weight of all monomers in the acrylate copolymer;

[0025] All monomers in the acrylate copolymer include: acrylate soft monomers, acrylate hard monomers, hydroxyl-containing acrylic monomers, carboxyl-containing acrylic monomers, acrylamide monomers, and ethoxy group-containing acrylic monomers.

[0026] Preferably, in the above pressure-sensitive adhesive, the antistatic agent is an ionic compound that is liquid or solid at room temperature;

[0027] The antioxidant is one or more of aromatic amine antioxidants, hindered phenol antioxidants, phosphate esters antioxidants, and thioether antioxidants;

[0028] The silane coupling agent is one or more of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-(methacryloyloxy)propyltrimethoxysilane, and vinyltrimethoxysilane;

[0029] The curing agent is one or more of trifunctional isocyanates, modified isocyanate compounds, and polyfunctional epoxy compounds.

[0030] A preparation method of the aging-resistant acrylic pressure-sensitive adhesive for TFT-LCD polarizers according to the present invention, characterized by comprising:

[0031] Take each raw material according to the acrylic pressure-sensitive adhesive formula of the present invention. Add an antistatic agent, an antioxidant, and a diluting solvent to the acrylate copolymer having alkyl, hydroxyl, carboxyl, alkylamino, amide, and ethoxy group structures in the side chain of the raw materials. After stirring evenly, add a curing agent and mix evenly to obtain the aging-resistant acrylic pressure-sensitive adhesive for TFT-LCD polarizers.

[0032] Preferably, in the above method, the acrylate copolymer having alkyl, hydroxyl, carboxyl, alkylamino, amide, and ethoxy group structures in the side chain is prepared in the following manner, including:

[0033] Add acrylate soft monomer, acrylate hard monomer, hydroxy-containing acrylic monomer, carboxyl-containing acrylic monomer, acrylamide monomer, ethoxy-containing acrylic monomer, initiator and solvent into the reaction kettle and dropping tank device respectively, mix them evenly, set the external temperature to 60-80°C, under the N2 atmosphere, heat up. When the materials in the reaction kettle reflux and foam, start to uniformly drop the materials in the dropping tank, and carry out the reaction by means of segmented free radical solution polymerization. Record the reaction temperature, titration time and the maximum value of the internal temperature in the initial stage of titration. After the dropping is completed, adjust the external temperature to 90-100°C, carry out the first heat preservation reaction for 0.5-2 hours, then add the first post-initiator, and then carry out the second heat preservation reaction for 0.5-2 hours, then add the second post-initiator, and then carry out the third heat preservation reaction for 0.5-2 hours, then add the third post-initiator, and carry out the heat preservation reaction for 0.5-3 hours. Cool down to below 40°C, add solvent for dilution, stir evenly, filter, and the copolymer obtained after discharging is the acrylate copolymer.

[0034] Preferably, in the above method, the solvent is one or more of ethyl acetate, methyl ethyl ketone, butyl acetate, methyl acetate, toluene, isopropyl alcohol, methanol;

[0035] The initiator is one or more of azobisisobutyronitrile, azobisisoheptonitrile, azobisisopentanenitrile, benzoyl peroxide, tert-butyl peroxy-2-ethylhexanoate, tert-amyl peroxy-2-ethylhexanoate.

[0036] Compared with the prior art, the anti-aging acrylic pressure-sensitive adhesive for TFT-LCD polarizers and its preparation method provided by the present invention have the following beneficial effects:

[0037] By adding acrylamide monomer and ethoxy-containing acrylic monomer as special monomers into the acrylate copolymer, covalent bonds, hydrogen bonds and van der Waals forces are formed between macromolecules, thereby enhancing the cohesion of the polymer. The characteristic peak (<3500cm of the associated hydrogen bond was found by Fourier transform infrared spectroscopy (FT-IR) -1) It shows that the carbonyl group in the above acrylamide structural unit is prone to form hydrogen bond interactions with O-H in the carboxyl group, hydroxyl group (O-H), and N-H on the amide group. It should be noted that N,N-dimethylaminopropyl acrylamide, N,N-diethyl acrylamide, N-isopropyl acrylamide, acryloylmorpholine, etc. are all monomers with LCST (lower critical solution temperature) characteristics. Above the LCST temperature, the homopolymers of these monomers can undergo phase changes in water, which is attributed to the enhancement of intermolecular forces. The LCST temperatures of the above monomers are 35°C, 33°C, 32°C, and 88°C respectively. It can be seen that the acrylate copolymer with hydroxyl, carboxyl, alkylamino, amide, and ethoxy structures in the side chain in the present invention has an LCST characteristic structural unit, so that the intermolecular forces of the pressure-sensitive adhesive are strengthened at high temperatures, thereby improving the high-temperature and high-humidity aging resistance and suppressing the "light leakage" phenomenon. In addition, the nitrogen atom in the acrylamide structural unit can also complex the antistatic agent cation, thereby providing an antistatic effect; the amide monomer has a certain hydrophilicity and can disperse and bind water molecules during the high-temperature and high-humidity aging process to prevent the formation of "water mist", thereby improving the light transmittance. At the same time, by embedding ethoxy repeating units in the acrylate copolymer, on the one hand, this structure can play an internal plasticization role, thereby endowing the pressure-sensitive adhesive with a certain stress relaxation ability, and on the other hand, the O atom in the C-O-C structure has a lone pair of electrons and can complex the antistatic agent cation. It should be noted that the prior art improves the antistatic property of the pressure-sensitive adhesive by adding an ester plasticizer (small molecule compound) containing one or more ether bonds. The ethoxy structure in the present invention is covalently bonded to the polymer main chain, and under high-temperature and high-humidity conditions, the stress relaxation performance and antistatic effect provided by the ethoxy structural unit are more stable. Brief Description of the Drawings

[0038] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for description in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0039] Figure 1 It is a schematic diagram of the test method for the acrylic pressure-sensitive adhesive provided by the embodiment of the present invention to resist light leakage. Detailed Embodiments

[0040] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the specific content of the present invention; obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments, which do not constitute a limitation to the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present invention.

[0041] First, the terms that may be used in this article are explained as follows:

[0042] The term "and / or" means that either or both of the two can be realized. For example, X and / or Y means that it includes three cases: the case of "X" or "Y" and the case of "X and Y".

[0043] Descriptions such as the terms "comprising", "including", "containing", "having" or other similar semantics should be interpreted as non-exclusive inclusion. For example: including a technical feature element (such as raw materials, components, ingredients, carriers, dosage forms, materials, dimensions, parts, components, mechanisms, devices, steps, processes, methods, reaction conditions, processing conditions, parameters, algorithms, signals, data, products or articles, etc.) should be interpreted as not only including the explicitly listed technical feature element, but also including other technical feature elements well-known in the art that are not explicitly listed.

[0044] The term "consisting of" means excluding any technical feature elements not explicitly listed. If this term is used in a claim, then this term will make the claim a closed type, making it not contain technical feature elements other than the explicitly listed ones, except for related conventional impurities. If this term only appears in a sub-clause of a claim, then it only limits the elements explicitly listed in that sub-clause, and the elements recorded in other sub-clauses are not excluded from the overall claim.

[0045] The term "parts by mass" represents the mass ratio relationship between multiple components. For example: if it is described that component X is x parts by mass and component Y is y parts by mass, then it means that the mass ratio of component X to component Y is x:y; 1 part by mass can represent any mass. For example: 1 part by mass can be expressed as 1 kg or 3.1415926 kg, etc. The sum of the parts by mass of all components is not necessarily 100 parts, and it can be greater than 100 parts, less than 100 parts or equal to 100 parts. Unless otherwise specified, the parts, ratios and percentages described in this article are all by mass.

[0046] When a concentration, temperature, pressure, dimension or other parameter is expressed in the form of a numerical range, this numerical range should be understood as specifically disclosing all ranges formed by the pairing of any upper limit value, lower limit value, and preferred value within this numerical range, regardless of whether this range is explicitly recorded; for example, if the numerical range "2 - 8" is recorded, then this numerical range should be interpreted as including ranges such as "2 - 7", "2 - 6", "5 - 7", "3 - 4 and 6 - 7", "3 - 5 and 7", "2 and 5 - 7", etc. Unless otherwise specified, the numerical ranges recorded in this article include both their end values and all integers and fractions within this numerical range.

[0047] The solution provided by the present invention will be described in detail below. The content not described in detail in the embodiments of the present invention belongs to the prior art well-known to those skilled in the art. In the embodiments of the present invention, those not specified in specific conditions are carried out according to the conventional conditions in the art or the conditions recommended by the manufacturer. The reagents or instruments used in the embodiments of the present invention not specified in the manufacturer are all conventional products that can be obtained by purchasing in the market.

[0048] An embodiment of the present invention provides an aging-resistant acrylic pressure-sensitive adhesive for a TFT-LCD polarizer. The pressure-sensitive adhesive is composed of an acrylate copolymer having alkyl, hydroxyl, carboxyl, alkylamino, amide, and ethoxy groups in the side chain, an antistatic agent, an antioxidant, a silane coupling agent, and a curing agent. The solid content of the pressure-sensitive adhesive is 10% to 60%, preferably 15% to 30%; wherein, the weight-average molecular weight of the acrylate copolymer is 800,000 to 2,000,000; the acrylate copolymer is a copolymer formed by free radical solution polymerization of acrylate soft monomers, acrylate hard monomers, hydroxyl-containing acrylic monomers, carboxyl-containing acrylic monomers, acrylamide monomers, and ethoxy group-containing acrylic monomers.

[0049] Preferably, in the above pressure-sensitive adhesive, in the acrylate copolymer, the weight fractions of the hydroxyl-containing acrylic monomer, the carboxyl-containing acrylic monomer, the acrylamide monomer, and the ethoxy group-containing acrylic monomer in the total weight of all monomers are 0.01% to 20%, 0.01% to 10%, 0.01% to 20%, and 0.01% to 20%, respectively.

[0050] Preferably, in the above pressure-sensitive adhesive, the acrylate soft monomer is one or more of octadecyl acrylate, dodecyl acrylate, isooctyl acrylate, octyl acrylate, n-butyl acrylate, isobutyl acrylate, n-propyl acrylate, and ethyl acrylate;

[0051] The acrylate hard monomer is one or more of methyl acrylate, methyl methacrylate, acrylonitrile, styrene, isobutyl methacrylate, tert-butyl methacrylate, and vinyl acetate;

[0052] The carboxyl-containing acrylic monomer is one or more of acrylic acid, methacrylic acid, and itaconic acid;

[0053] The acrylamide monomer is one or more of N,N-dimethylaminopropyl acrylamide, N,N-dimethylaminopropyl methacrylamide, N,N-diethylaminopropyl acrylamide, N,N-diethylaminopropyl methacrylamide, N,N-dimethylacrylamide, N,N-diethylacrylamide, N-isopropylacrylamide, and acryloylmorpholine; in the acrylate copolymer with a side chain having a hydroxyl group, a carboxyl group, an alkylamino group, an amide group, and an ethoxy structure, when N,N-dimethylaminopropyl acrylamide or N,N-diethylacrylamide or acryloylmorpholine and acrylamide are used as special monomers, the pressure-sensitive adhesive has excellent durability.

[0054] The ethoxy group-containing acrylic monomer is one or more of ethoxyethoxyethyl acrylate, ethoxyethyl acrylate, ethoxyethoxymethyl acrylate, ethoxymethyl acrylate, and methoxyethyl acrylate.

[0055] Preferably, in the above pressure-sensitive adhesive, the acrylate copolymer is copolymerized by radical solution stepwise polymerization in the following manner, including:

[0056] Add acrylate soft monomer, acrylate hard monomer, hydroxyl group-containing acrylic monomer, carboxyl group-containing acrylic monomer, acrylamide monomer, ethoxy group-containing acrylic monomer, initiator, and solvent into the reaction kettle and dropping tank device respectively and mix evenly. Set the external temperature to 60-80 °C. Under the N2 atmosphere, heat up. When the materials in the reaction kettle reflux and foam, start to uniformly drop the materials in the dropping tank. React by the method of stepwise radical solution polymerization. Record the reaction temperature, titration time, and the maximum value of the internal temperature in the initial stage of titration. After the dropping is completed, adjust the external temperature to 90-100 °C and carry out the first heat preservation reaction for 0.5-2 hours. Then add the first post-initiator, and then carry out the second heat preservation reaction for 0.5-2 hours. Then add the second post-initiator, and then carry out the third heat preservation reaction for 0.5-2 hours. Then add the third post-initiator and carry out the heat preservation reaction for 0.5-3 hours. Cool down to below 40 °C, add solvent for dilution, stir evenly, filter, and discharge. The obtained copolymer is the acrylate copolymer.

[0057] Preferably, in the above pressure-sensitive adhesive, the solvent is one or more of ethyl acetate, methyl ethyl ketone, butyl acetate, methyl acetate, toluene, isopropyl alcohol, and methanol;

[0058] The initiator is one or more of azobisisobutyronitrile, azobisisoheptonitrile, azobisisopentanenitrile, benzoyl peroxide, tert-butyl peroxy-2-ethylhexanoate, and tert-amyl peroxy-2-ethylhexanoate.

[0059] The above-mentioned acrylate copolymer is prepared by a free radical step polymerization process. The first stage of polymerization is carried out at a lower temperature (60 - 80 °C), and the second stage of polymerization is carried out at a higher temperature (90 - 100 °C). The low-temperature reaction helps to form a high molecular weight polymer. At a higher reaction temperature, the polymerization rate increases while the degree of polymerization decreases. By controlling the polymerization reaction parameters of each stage, a polymer with both high cohesion and certain mechanical relaxation properties is synthesized. Furthermore, when the polarizer undergoes high-temperature and high-humidity aging, the strong cohesion can inhibit the shrinkage of PVA, and at the same time, the relaxation characteristics of the pressure-sensitive adhesive can release the internal stress generated by the local shrinkage of PVA, thus achieving the effect of inhibiting "light leakage".

[0060] Preferably, in the above-mentioned pressure-sensitive adhesive, the weight fraction of the antistatic agent in the total weight of all monomers in the acrylate copolymer is 0.01 - 10%;

[0061] The weight fraction of the antioxidant in the total weight of all monomers in the acrylate copolymer is 0.01 - 10%;

[0062] The weight fraction of the silane coupling agent in the total weight of all monomers in the acrylate copolymer is 0.001 - 10%;

[0063] The weight fraction of the curing agent in the total weight of all monomers in the acrylate copolymer is 0.001 - 10%;

[0064] All monomers in the acrylate copolymer include: acrylate soft monomers, acrylate hard monomers, hydroxy-containing acrylic monomers, carboxyl-containing acrylic monomers, acrylamide monomers, and ethoxy-containing acrylic monomers.

[0065] Preferably, in the above-mentioned pressure-sensitive adhesive, the antistatic agent is an ionic compound that is liquid or solid at room temperature. Preferably, the ionic compound is an inorganic salt or organic salt of an alkali metal;

[0066] The antioxidant is one or more of aromatic amine antioxidants, hindered phenol antioxidants, phosphate antioxidants, and thioether antioxidants;

[0067] The silane coupling agent is one or more of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-(methacryloyloxy)propyltrimethoxysilane, and vinyltrimethoxysilane;

[0068] The curing agent is one or more of trifunctional isocyanates, modified isocyanate compounds, and polyfunctional epoxy compounds.

[0069] A preparation method of an aging-resistant acrylic pressure-sensitive adhesive for a TFT-LCD polarizer according to the present invention, characterized by comprising:

[0070] Take each raw material according to the acrylic pressure-sensitive adhesive formula of the present invention. Add an antistatic agent, an antioxidant, a silane coupling agent and a diluting solvent to the acrylate copolymer having alkyl, hydroxyl, carboxyl, alkylamino, amide and ethoxy structures in the side chain of the raw materials. After stirring evenly, add a curing agent and mix evenly to obtain an aging-resistant acrylic pressure-sensitive adhesive for TFT-LCD polarizing plates.

[0071] Preferably, in the above method, the acrylate copolymer having alkyl, hydroxyl, carboxyl, alkylamino, amide and ethoxy structures in the side chain is prepared in the following manner, including:

[0072] Add acrylate soft monomer, acrylate hard monomer, hydroxyl-containing acrylic monomer, carboxyl-containing acrylic monomer, acrylamide monomer, ethoxy structure-containing acrylic monomer, initiator and solvent to the reaction kettle and dropping tank device respectively and mix evenly. Set the external temperature to 60-80 °C. Under the N2 atmosphere, heat up. When the materials in the reaction kettle reflux and foam, start to uniformly drop the materials in the dropping tank. React by means of segmented free radical solution polymerization. Record the reaction temperature, titration time and the maximum value of the internal temperature in the initial stage of titration. After the dropping is completed, adjust the external temperature to 90-100 °C and carry out the first heat preservation reaction for 0.5-2 hours. Then add the first post-initiator, and then carry out the second heat preservation reaction for 0.5-2 hours. Then add the second post-initiator, and then carry out the third heat preservation reaction for 0.5-2 hours. Then add the third post-initiator and carry out the heat preservation reaction for 0.5-3 hours. Cool down to below 40 °C, add solvent for dilution, stir evenly, filter and discharge to obtain the copolymer, which is the acrylate copolymer.

[0073] In the above method, the function of recording the reaction temperature: on the one hand, it is to confirm the temperature of the reaction between primary free radicals and monomers, and on the other hand, it is to compare with the production process parameters to ensure the correctness of production operations.

[0074] The function of recording the titration time: Take this moment as the starting node of titration, deduce the uniform dropping rate, and ensure that the materials are dropped within a certain time.

[0075] Due to the use of segmented polymerization, by respectively controlling the reaction concentration, reaction temperature, stirring rate of each segment and by controlling the amount of titrated materials and titration rate, the molecular weight and molecular weight distribution of the polymer can be well adjusted.

[0076] Preferably, in the above method, the solvent is one or more of ethyl acetate, methyl ethyl ketone, butyl acetate, methyl acetate, toluene, isopropyl alcohol, methanol;

[0077] The initiator is one or more of azobisisobutyronitrile, azobisisoheptonitrile, azobisisopentanenitrile, benzoyl peroxide, tert-butyl peroxy-2-ethylhexanoate, tert-amyl peroxy-2-ethylhexanoate.

[0078] In summary, for the anti-aging pressure-sensitive adhesive and its preparation method according to the embodiments of the present invention, by adding acrylamide monomers and acrylic monomers containing an ethoxy structure as special monomers to an acrylate copolymer having alkyl, hydroxyl, carboxyl, alkylamino, amide, and ethoxy structures in the side chain, covalent bonds, hydrogen bonds, and van der Waals forces are formed between macromolecules, thereby enhancing the cohesion of the polymer. At the same time, it is found that the side chain of this acrylate copolymer has hydroxyl, carboxyl, alkylamino, amide, and ethoxy structures. When N,N-dimethylaminopropyl acrylamide or N,N-diethylacrylamide or acryloylmorpholine and acrylamide are used as special monomers, the pressure-sensitive adhesive has excellent durability. Through Fourier transform infrared spectroscopy (FT-IR) characterization, characteristic peaks (<3500 cm -1 ) of associated hydrogen bonds are found, indicating that the carbonyl group in the above acrylamide structural units is prone to form hydrogen bond interactions with O-H in the carboxyl group, hydroxyl (O-H), and N-H on the amide group. It should be noted that N,N-dimethylaminopropyl acrylamide, N,N-diethylacrylamide, N-isopropylacrylamide, acryloylmorpholine, etc. are all monomers with the characteristics of LCST (lower critical solution temperature). As is well known, above the LCST temperature, the homopolymers of these monomers can undergo phase changes in water, attributed to the enhancement of intermolecular forces. The LCST temperatures of the above monomers are 35 °C, 33 °C, 32 °C, and 88 °C respectively. It can be seen that the acrylate copolymer with hydroxyl, carboxyl, alkylamino, amide, and ethoxy structures in the side chain in the present invention has an LCST characteristic structural unit, so that the intermolecular forces of the pressure-sensitive adhesive are strengthened at high temperatures, thereby improving the high-temperature and high-humidity aging resistance and suppressing the "light leakage" phenomenon. In addition, the nitrogen atom in the acrylamide structural unit can also complex with the antistatic agent cation, thereby providing an antistatic effect; the amide monomer has a certain hydrophilicity and can disperse and bind water molecules during the high-temperature and high-humidity aging process to prevent the formation of "water mist", thereby improving the light transmittance. By embedding ethoxy repeating units in the acrylate copolymer, on the one hand, this structure can play an internal plasticizing role, thereby endowing the pressure-sensitive adhesive with a certain stress relaxation ability. On the other hand, the O atom in the C-O-C structure has a lone pair of electrons and can complex with the antistatic agent cation. It should be noted that the prior art improves the antistatic property of the pressure-sensitive adhesive by adding an ester plasticizer (small molecule compound) containing one or more ether bonds. The ethoxy structure in the present invention is covalently bonded to the polymer main chain, and under high-temperature and high-humidity conditions, the stress relaxation performance and antistatic effect provided by the ethoxy structural unit are more stable. The acrylic pressure-sensitive adhesive provided by the present invention is used for bonding between a polarizer and a liquid crystal cell glass, and has excellent adhesion, durability, and antistatic property.

[0079] To more clearly demonstrate the technical solutions provided by the present invention and the resulting technical effects, the following uses specific embodiments to describe in detail the solutions provided by the embodiments of the present invention.

[0080] To more clearly demonstrate the technical solutions provided by the present invention and the resulting technical effects, the following uses specific embodiments to describe in detail the pressure-sensitive adhesive for polarizing films provided by the embodiments of the present invention and its preparation method.

[0081] Example 1

[0082] This example provides a pressure-sensitive adhesive for polarizing films. The acrylate copolymer (S1) used in this acrylic pressure-sensitive adhesive has the ingredients shown in Table 1:

[0083] Table 1 is the ingredient table of the acrylate copolymer (S1)

[0084]

[0085] The preparation method of the above acrylate copolymer includes the following steps:

[0086] Add the acrylic monomers, initiators, and solvents in the above table into the reaction kettle and the dropping tank device respectively, mix evenly, set the external temperature to 60 - 80 °C, under the N2 atmosphere, heat up. When the materials in the reaction kettle reflux and foam, start uniform dropping. After dropping for a period of time, adjust the external temperature to 90 - 100 °C, carry out the first heat preservation reaction for 0.5 - 2 hours, then add the first post-initiator, and then carry out the second heat preservation reaction for 0.5 - 2 hours. Then add the second post-initiator, and then carry out the third heat preservation reaction for 0.5 - 2 hours. Then add the third post-initiator, carry out the heat preservation reaction for 0.5 - 3 hours, cool down to below 40 °C, add solvent for dilution, stir evenly, filter, and discharge to obtain the acrylate copolymer (S1).

[0087] The pressure-sensitive adhesive for polarizing films in this example has the ingredients shown in Table 2:

[0088] Table 2 is the ingredient table of the pressure-sensitive adhesive in Example 1

[0089]

[0090]

[0091] The preparation method of the above acrylic pressure-sensitive adhesive is as follows:

[0092] Add 0.2 g of antistatic agent, 0.1 g of antioxidant, 0.1 g of silane coupling agent, and dilution solvent to 100 g of acrylate copolymer (S1). After stirring evenly, add 0.5 g of curing agent, and stir to obtain the pressure-sensitive adhesive for polarizing films.

[0093] Example 2

[0094] This example provides a pressure - sensitive adhesive for polarizing films. The difference compared with Example 1 is that the acrylamide monomer structure is added. The acrylate copolymer (S2) used in this acrylic pressure - sensitive adhesive has the ingredients shown in Table 3:

[0095] Table 3 is the ingredient table of acrylate copolymer (S2).

[0096]

[0097] The preparation method of the acrylate copolymer (S2) in this example is the same as that in Example 1. Please refer to Example 1.

[0098] The ingredient table and preparation method of the acrylic pressure - sensitive adhesive in this example are the same as those in Example 1. Please refer to Example 1.

[0099] Example 3

[0100] This example provides a pressure - sensitive adhesive for polarizing films. The difference compared with Example 2 is that the N,N - dimethylaminopropyl acrylamide monomer structure is added. The acrylate copolymer (S3) used in this acrylic pressure - sensitive adhesive has the ingredients shown in Table 4:

[0101] Table 4 is the ingredient table of acrylate copolymer (S3).

[0102]

[0103]

[0104] The preparation method of the acrylate copolymer (S3) in this example is the same as that in Example 1. Please refer to Example 1.

[0105] The ingredient table and preparation method of the acrylic pressure - sensitive adhesive in this example are the same as those in Example 1. Please refer to Example 1.

[0106] Example 4

[0107] This example provides a pressure - sensitive adhesive for polarizing films. The difference compared with Example 3 is that the content of the acrylic monomer with an ethoxy structure is increased. The acrylate copolymer (S4) used in this acrylic pressure - sensitive adhesive has the ingredients shown in Table 5:

[0108] Table 5 is the ingredient table of acrylate copolymer S4.

[0109]

[0110] The preparation method of the acrylate copolymer (S4) in this example is the same as that in Example 1. Please refer to Example 1.

[0111] The ingredient list and preparation method of the acrylic pressure-sensitive adhesive in this example are the same as those in Example 1. Please refer to Example 1.

[0112] Comparative Example 1

[0113] This example provides a pressure-sensitive adhesive for polarizing films. The difference compared with Example 1 is that the polymerization reaction temperatures in the front and back stages are the same. For the acrylate copolymer (D1) used in this acrylic pressure-sensitive adhesive, the ingredients are shown in Table 6:

[0114] Table 6 is the ingredient list of the acrylate copolymer (D1)

[0115]

[0116] The preparation method of the above acrylate copolymer includes the following steps:

[0117] Add the acrylic monomers, initiators, and solvents in the above table into the reaction kettle and dropping tank device respectively, mix evenly, set the external temperature to 90 - 100 °C, under the N2 atmosphere, heat up. When the materials in the reaction kettle reflux and foam, start uniform dropping. After dropping for a period of time, keep the external temperature unchanged and carry out the first heat preservation reaction for 0.5 - 2 hours. Then add the first post-initiator, and then carry out the second heat preservation reaction for 0.5 - 2 hours. Then add the second post-initiator, and then carry out the third heat preservation reaction for 0.5 - 2 hours. Then add the third post-initiator, and carry out the heat preservation reaction for 0.5 - 3 hours. Cool down to below 40 °C, add solvent for dilution, stir evenly, filter, and discharge to obtain the acrylate copolymer (D1).

[0118] The ingredient list and preparation method of the acrylic pressure-sensitive adhesive in this example are the same as those in Example 1. Please refer to Example 1.

[0119] Comparative Example 2

[0120] This example provides a pressure-sensitive adhesive for polarizing films. The difference compared with Example 1 is that the N,N-diethylacrylamide monomer structure is removed. For the acrylate copolymer (D2) used in this acrylic pressure-sensitive adhesive, the ingredients are shown in Table 7:

[0121] Table 7 is the ingredient list of the acrylate copolymer (D2)

[0122]

[0123]

[0124] The preparation method of the acrylate copolymer (D2) in this example is the same as that in Example 1. Please refer to Example 1.

[0125] The ingredient list and preparation method of the acrylic pressure-sensitive adhesive in this example are the same as those in Example 1. Please refer to Example 1.

[0126] Comparative Example 3

[0127] This example provides a pressure-sensitive adhesive for polarizers, which is different from Comparative Example 2 in that: the content of the acrylic monomer containing an ethoxy structure is reduced. The acrylate copolymer (D3) used in this acrylic pressure-sensitive adhesive has the ingredient list shown in Table 8:

[0128] Table 8 is the ingredient list of acrylate copolymer D3

[0129]

[0130] The preparation method of the acrylate copolymer (D3) in this example is the same as that in Example 1. Please refer to Example 1.

[0131] The ingredient list and preparation method of the acrylic pressure-sensitive adhesive in this example are the same as those in Example 1. Please refer to Example 1.

[0132] It can be known that the above Comparative Examples 1, 2, and 3 are specially designed to compare the performance of the products of the present invention, and they are not prior art.

[0133] Tape samples were prepared by coating, drying, laminating, and curing using Examples 1, 2, 3, 4 and Comparative Examples 1, 2, 3 respectively for mechanical property testing. The data are shown in Table 9:

[0134] Table 9 is the mechanical property test data of the pressure-sensitive adhesive for polarizers

[0135]

[0136] Polarizer samples were prepared by coating, drying, laminating, and curing using Examples 1, 2, 3, 4 and Comparative Examples 1, 2, 3 respectively for the "light leakage" resistance test. The data are shown in Table 10:

[0137] Table 10 is the "light leakage" resistance test data of the pressure-sensitive adhesive for polarizers

[0138]

[0139] Appendix: The calculation formula for evaluating the "light leakage" problem is as follows:

[0140] After the polarizer is aged for a period of time, the shrinkage of PVA causes local internal stress, resulting in the distortion of the polarization axis, which causes a deviation in the cross-polarization between the upper and lower polarizing films, and finally a light leakage phenomenon occurs. As Figure 1As shown, polarizing films are attached to the upper and lower surfaces of a glass plate. After aging for a period of time, five points on one of the surfaces are taken, and the visible light transmittance is measured respectively to obtain the transmittance data T1, T2, T3, T4, and T5. According to the formula LLI (Light leakage index) = (T1 + T2 + T3 + T4) / 4 - T5, the effect of the pressure-sensitive adhesive in resisting "light leakage" is judged.

[0141] As can be seen from Table 9 and Table 10 above, the acrylic pressure-sensitive adhesive of the present invention has a low initial adhesion and a relatively good antistatic effect. After the polarizing film made of this pressure-sensitive adhesive is subjected to accelerated aging, the LLI value is low, and there is no light leakage phenomenon caused by shrinkage.

[0142] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims. The information disclosed in the background art part of this article is only intended to deepen the understanding of the overall background technology of the present invention, and should not be regarded as an admission or any form of suggestion that this information constitutes the prior art known to those skilled in the art.

Claims

1. An aging-resistant acrylic pressure-sensitive adhesive for TFT-LCD polarizer, characterized in that: The pressure-sensitive adhesive is composed of an acrylate copolymer having alkyl, hydroxyl, carboxyl, alkylamino, amide and ethoxy structures in the side chain, an antistatic agent, an antioxidant, a silane coupling agent and a curing agent, and the solid content of the pressure-sensitive adhesive is 10% to 60%; wherein the weight average molecular weight of the acrylate copolymer is 800,000 to 2,000,000; the acrylate copolymer is a copolymer formed by copolymerizing acrylate soft monomers, acrylate hard monomers, hydroxyl-containing acrylic monomers, carboxyl-containing acrylic monomers, acrylamide monomers and ethoxy-containing acrylic monomers through free radical solution polymerization.

2. The aging-resistant acrylic pressure-sensitive adhesive for TFT-LCD polarizer according to claim 1, characterized in that: In the acrylic ester copolymer, the weight fractions of the hydroxyl-containing acrylic monomer, carboxyl-containing acrylic monomer, acrylamide monomer, and ethoxy-containing acrylic monomer in the total weight of all monomers are 0.01-20%, 0.01-10%, 0.01-20%, and 0.01-20%, respectively.

3. The aging-resistant acrylic pressure-sensitive adhesive for TFT-LCD polarizer according to claim 1, characterized in that: The acrylic acid ester soft monomer is one or more of octadecyl acrylate, dodecyl acrylate, isooctyl acrylate, octyl acrylate, n-butyl acrylate, isobutyl acrylate, n-propyl acrylate, and ethyl acrylate; The acrylic acid ester hard monomer is one or more of methyl acrylate, methyl methacrylate, acrylonitrile, styrene, isobutyl methacrylate, tert-butyl methacrylate, and vinyl acetate; The carboxyl-containing acrylic acid monomer is one or more of acrylic acid, methacrylic acid and itaconic acid; The acrylamide monomer is one or more of N,N-dimethylaminopropyl acrylamide, N,N-dimethylaminopropyl methacrylamide, N,N-diethylaminopropyl acrylamide, N,N-diethylaminopropyl methacrylamide, N,N-dimethylacrylamide, N,N-diethylacrylamide, N-isopropylacrylamide and acryloylmorpholine; The ethoxy structure-containing acrylic monomer is one or more of ethoxyethoxyethyl acrylate, ethoxyethyl acrylate, ethoxyethoxymethyl acrylate, ethoxymethyl acrylate, and methoxyethyl acrylate.

4. The aging-resistant acrylic pressure-sensitive adhesive for TFT-LCD polarizer according to any one of claims 1 to 3, characterized in that: The acrylic acid ester copolymer is prepared by free radical solution segmented polymerization in the following manner, including: Add acrylate soft monomer, acrylate hard monomer, hydroxyl acrylic monomer, carboxyl acrylic monomer, acrylamide monomer, ethoxy structure acrylic monomer, initiator and solvent into the reaction kettle and drip tank device respectively, mix them evenly, set the external temperature to 60-80°C, heat and heat up in N2 atmosphere, when the material in the reaction kettle refluxes and foams, start to drip the material in the drip tank at a uniform speed, adopt the method of segmented free radical solution polymerization to react, record the reaction temperature, titration time and the maximum value of the internal temperature at the initial stage of titration, after the dripping is completed, adjust the external temperature to 90-100°C, carry out the first insulation reaction for 0.5-2 hours, then add the first post-initiator, carry out the second insulation reaction for 0.5-2 hours, add the second post-initiator, carry out the third insulation reaction for 0.5-2 hours, add the third post-initiator, carry out the insulation reaction for 0.5-3 hours, cool to below 40°C, add solvent to dilute, stir evenly, filter and discharge the obtained copolymer, which is the acrylate copolymer.

5. The aging-resistant acrylic pressure-sensitive adhesive for TFT-LCD polarizer according to claim 4, characterized in that: The solvent is one or more of ethyl acetate, butanone, butyl acetate, methyl acetate, toluene, isopropanol, and methanol; The initiator is one or more of azobisisobutyronitrile, azobisisoheptanenitrile, azobisisovaleronitrile, benzoyl peroxide, tert-butyl peroxy-2-ethylhexanoate, and tert-amyl peroxy-2-ethylhexanoate.

6. The aging-resistant acrylic pressure-sensitive adhesive for TFT-LCD polarizer according to any one of claims 1 to 3, characterized in that: The antistatic agent accounts for 0.01 to 10% of the total weight of all monomers in the acrylic ester copolymer; The antioxidant accounts for 0.01 to 10% of the total weight of all monomers in the acrylic ester copolymer; The silane coupling agent accounts for 0.001 to 10% of the total weight of all monomers in the acrylate copolymer; The curing agent accounts for 0.001 to 10% of the total weight of all monomers in the acrylate copolymer; All monomers in the acrylic ester copolymer include: acrylic ester soft monomers, acrylic ester hard monomers, hydroxyl-containing acrylic monomers, carboxyl-containing acrylic monomers, acrylamide monomers and ethoxy-containing acrylic monomers.

7. The aging-resistant acrylic pressure-sensitive adhesive for TFT-LCD polarizer according to claim 1 or 4, characterized in that: The antistatic agent is an ionic compound that is liquid or solid at room temperature; The antioxidant is one or more of aromatic amine antioxidants, hindered phenol antioxidants, phosphate antioxidants and thioether antioxidants; The silane coupling agent is one or more of γ-aminopropyl triethoxysilane, γ-glycidyloxypropyl trimethoxysilane, γ-(methacryloyloxy)propyl trimethoxysilane, and vinyl trimethoxysilane; The curing agent is one or more of trifunctional isocyanate, modified isocyanate compound and multifunctional epoxy compound.

8. A method for preparing the aging-resistant acrylic pressure-sensitive adhesive for TFT-LCD polarizer according to any one of claims 1 to 7, characterized in that: include: The raw materials are taken according to the acrylic pressure-sensitive adhesive formula of any one of claims 1 to 7, and an antistatic agent, an antioxidant, a silane coupling agent and a diluent solvent are added to the acrylic ester copolymer having an alkyl, hydroxyl, carboxyl, alkylamino, amide and ethoxy structure in the side chain of the raw materials, and after stirring evenly, a curing agent is added and mixed evenly to obtain an aging-resistant acrylic pressure-sensitive adhesive for TFT-LCD polarizer.

9. The method for preparing the aging-resistant acrylic pressure-sensitive adhesive for TFT-LCD polarizer according to claim 8, characterized in that: The acrylic acid ester copolymer having side chains having alkyl, hydroxyl, carboxyl, alkylamino, amide and ethoxy structures is prepared in the following manner, including: Add acrylic soft monomer, acrylic hard monomer, hydroxyl acrylic monomer, carboxyl acrylic monomer, acrylamide monomer, ethoxy structure acrylic monomer, initiator and solvent into the reaction kettle and drip tank device respectively, mix them evenly, set the external temperature to 60-80°C, heat and heat up in N2 atmosphere, when the material in the reaction kettle refluxes and foams, start to drip the material in the drip tank at a uniform speed, adopt the method of segmented free radical solution polymerization to react, record the reaction temperature, titration time and the maximum value of the internal temperature at the initial stage of titration, after the dripping is completed, adjust the external temperature to 90-100°C, carry out the first insulation reaction for 0.5-2 hours, then add the first post-initiator, carry out the second insulation reaction for 0.5-2 hours, add the second post-initiator, carry out the third insulation reaction for 0.5-2 hours, add the third post-initiator, carry out the insulation reaction for 0.5-3 hours, cool to below 40°C, add solvent to dilute, stir evenly, filter and discharge the obtained copolymer, which is the acrylic ester copolymer.

10. The method for preparing the aging-resistant acrylic pressure-sensitive adhesive for TFT-LCD polarizer according to claim 9, characterized in that: The solvent is one or more of ethyl acetate, butanone, butyl acetate, methyl acetate, toluene, isopropanol, and methanol; The initiator is one or more of azobisisobutyronitrile, azobisisoheptanenitrile, azobisisovaleronitrile, benzoyl peroxide, tert-butyl peroxy-2-ethylhexanoate, and tert-amyl peroxy-2-ethylhexanoate.

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