Antistatic agent, pressure-sensitive adhesive, and use thereof

Abstract

The application discloses an antistatic agent, a pressure-sensitive adhesive and application thereof, and belongs to the technical field of protective films. The antistatic agent is prepared by copolymerization of the following monomers in parts by weight: 15-25 parts of a quaternary ammonium salt monomer, 20-30 parts of a first acrylate soft monomer, 3-8 parts of a first acrylate hard monomer and 1-5 parts of a hydroxyl-containing monomer. The antistatic agent is a quaternary ammonium salt acrylate copolymer prepared by copolymerization of the quaternary ammonium salt monomer, the acrylate soft monomer, the acrylate hard monomer and the hydroxyl-containing monomer. The copolymer has both a quaternary ammonium salt conductive group and an acrylate group. The acrylate group can deeply participate in photopolymerization, so that the quaternary ammonium salt group with a conductive function is firmly anchored on the adhesive copolymer molecular chain through a covalent bond, thereby effectively solving the migration and precipitation problems of the antistatic component and realizing long-acting antistatic performance.

Description

Technical Field

[0001] This application relates to the field of protective film technology, and in particular to an antistatic agent, a pressure-sensitive adhesive, and their applications. Background Technology

[0002] The core function of polarizer protective film is to provide full-process protection for polarizers: during the performance testing stage, it ensures that the optical performance is not affected by external interference, and during the shipping and transportation process, it can effectively resist scratches, dirt and dust adhesion, and prevent the polarizer from being damaged and affecting the display effect of terminal equipment.

[0003] Polarizers are precision optical components, and static electricity can easily cause them to attract dust particles and even damage their internal optical structures. Therefore, polarizer protective films must have stable antistatic effects. This not only requires controlling the surface resistance of the adhesive surface to a low value range to quickly dissipate static electricity, but also ensuring that the antistatic performance is long-lasting and stable with no risk of component migration. Summary of the Invention

[0004] This application provides an antistatic agent, a pressure-sensitive adhesive, and their applications. The technical solution is as follows: On the one hand, an antistatic agent is provided, said antistatic agent being copolymerized from the following monomers in parts by weight: 15-25 parts of quaternary ammonium salt monomer, 20-30 parts of soft monomer of first acrylate, 3-8 parts of hard monomer of first acrylate, and 1-5 parts of hydroxyl-containing monomer.

[0005] In one possible implementation, the quaternary ammonium salt monomer is selected from at least one of methacryloyloxyethyltrimethylammonium chloride, methacryloyloxyethyltriethylammonium chloride, acryloyloxyethyltrimethylammonium chloride, and methacryloyloxyethyldimethylbenzylammonium chloride.

[0006] In another possible implementation, the first acrylate soft monomer is selected from at least one of isooctyl acrylate, butyl acrylate, isobutyl acrylate, hexyl acrylate, isodecanyl acrylate, and tridecyl acrylate.

[0007] In another possible implementation, the first acrylate hard monomer is selected from at least one of methyl methacrylate, methyl acrylate, ethyl methacrylate, cyclohexyl methacrylate, and isobornyl acrylate.

[0008] In another possible implementation, the hydroxyl-containing monomer is selected from at least one of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyethyl methacrylate, and hydroxypropyl methacrylate.

[0009] On the other hand, a method for preparing an antistatic agent is provided, wherein the antistatic agent is as described in any of the above claims, and the preparation method includes: Obtain a mixture comprising a quaternary ammonium salt monomer, a first acrylate soft monomer, a first acrylate hard monomer, and a hydroxyl-containing monomer; The mixture is subjected to a copolymerization reaction initiated by an initiator to obtain a copolymer solution; The copolymer solution was purified and dried to obtain the antistatic agent.

[0010] On the other hand, a pressure-sensitive adhesive is provided, the pressure-sensitive adhesive comprising the following components in parts by weight: 100 parts of adhesive copolymer, 0.05 to 0.15 parts of photoinitiator, and 1 to 2.5 parts of ionic liquid; The adhesive copolymer is copolymerized from the following components in parts by weight: 1 to 3 parts of antistatic agent, 60 to 75 parts of soft monomer of second acrylate, 0 to 7 parts of hard monomer of second acrylate, 5 to 15 parts of hydroxyl-containing monomer, and 15 to 25 parts of monomer containing ether bond; The antistatic agent is as described in any of the above.

[0011] In one possible implementation, the ionic liquid is selected from at least one of 1-vinyl-3-butylimidazolium bis(trifluoromethanesulfonyl)imide, 1-vinyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-vinyl-3-hexylimidazolium bis(trifluoromethanesulfonyl)imide, 1-allyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, and 1-vinyl-3-butylimidazolium hexafluorophosphate.

[0012] In another possible implementation, the ether-containing monomer is selected from at least one of methoxyethyl acrylate, ethoxyethoxyethyl acrylate, ethoxymethacrylate, propoxyethyl acrylate, methoxyethoxyethyl methacrylate, diethylene glycol monoacrylate, polyethylene glycol methacrylate, polyethylene glycol acrylate, and polypropylene glycol methacrylate.

[0013] In another possible implementation, the second acrylate soft monomer is selected from at least one of isooctyl acrylate, butyl acrylate, isobutyl acrylate, isodecanyl acrylate, tridecyl acrylate, 2-ethylhexyl acrylate and their isomers.

[0014] In another possible implementation, the second acrylate hard monomer is selected from at least one of methyl methacrylate, isobornyl methacrylate, methyl acrylate, ethyl acrylate, tert-butyl methacrylate, and cyclohexyl methacrylate.

[0015] On the other hand, a method for preparing a pressure-sensitive adhesive is provided, characterized in that the pressure-sensitive adhesive is as described in any of the above claims, and the preparation method includes: Preparation of adhesive copolymers; The pressure-sensitive adhesive is obtained by mixing the adhesive copolymer, photoinitiator and ionic liquid.

[0016] In one possible implementation, the preparation of the adhesive copolymer includes: An antistatic agent, a second acrylate soft monomer, a second acrylate hard monomer, a hydroxyl-containing monomer, an ether-containing monomer, and a photoinitiator are mixed to obtain a mixture. The mixture is irradiated under an ultraviolet light source to initiate a copolymerization reaction, thereby obtaining the adhesive copolymer.

[0017] On the other hand, a polarizer protective film is provided, the polarizer protective film comprising: a substrate, an adhesive layer and a release film, wherein the adhesive layer is located between the substrate and the release film; The adhesive layer is formed by light curing a pressure-sensitive adhesive, and the pressure-sensitive adhesive is as described in any of the above.

[0018] On the other hand, a display device is provided, the display device comprising: a display panel, a polarizer disposed on the display panel, and a polarizer protective film adhered to the surface of the polarizer, the polarizer protective film being as described above.

[0019] This application provides an antistatic agent, which is a quaternary ammonium salt acrylate copolymer formed by copolymerizing quaternary ammonium salt monomers, acrylate soft monomers, acrylate hard monomers, and hydroxyl-containing monomers. This copolymer possesses both quaternary ammonium salt conductive groups and acrylate groups. The acrylate groups can deeply participate in the photopolymerization reaction, allowing the conductive quaternary ammonium salt groups to be firmly anchored to the adhesive copolymer molecular chain through covalent bonds. This effectively solves the problems of migration and precipitation of antistatic components, achieving long-lasting antistatic performance. Furthermore, the copolymer itself has good structural compatibility with the active monomers used to prepare the adhesive copolymer and can be completely integrated into the adhesive copolymer molecular chain system through participation in the polymerization reaction. Simultaneously, the hydroxyl-containing monomers in the copolymer molecular chain can form hydrogen bonds through the hydroxyl groups, further improving the system's miscibility and effectively solving phase separation and aggregation problems. This avoids affecting the core optical indicators of the polarizer protective film itself, such as light transmittance, thereby meeting the stringent optical protection requirements of equipment. Attached Figure Description

[0020] Figure 1 This is a flowchart of an antistatic agent preparation method provided in the embodiments of this application; Figure 2 This is a flowchart of a method for preparing a pressure-sensitive adhesive provided in an embodiment of this application; Figure 3 This is a schematic diagram of the structure of a polarizer protective film provided in an embodiment of this application; Figure 4 This is a schematic diagram of a structure provided in this application embodiment for attaching a polarizer protective film onto a polarizer. Detailed Implementation

[0021] To make the technical solution and advantages of this application clearer, the embodiments of this application will be described in further detail below.

[0022] The terms "first," "second," "third," and "fourth," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0023] On one hand, embodiments of this application provide an antistatic agent, which is copolymerized from the following monomers in parts by weight: 15-25 parts of quaternary ammonium salt monomer, 20-30 parts of soft monomer of first acrylate, 3-8 parts of hard monomer of first acrylate, and 1-5 parts of hydroxyl-containing monomer.

[0024] This application provides an antistatic agent, which is a quaternary ammonium salt acrylate copolymer formed by copolymerizing quaternary ammonium salt monomers, acrylate soft monomers, acrylate hard monomers, and hydroxyl-containing monomers. This copolymer possesses both quaternary ammonium salt conductive groups and acrylate groups. The acrylate groups can deeply participate in the photopolymerization reaction, allowing the conductive quaternary ammonium salt groups to be firmly anchored to the adhesive copolymer molecular chain through covalent bonds. This effectively solves the problems of migration and precipitation of antistatic components, achieving long-lasting antistatic performance. Furthermore, the copolymer itself has good structural compatibility with the active monomers used to prepare the adhesive copolymer and can be completely integrated into the adhesive copolymer molecular chain system through participation in the polymerization reaction. Simultaneously, the hydroxyl-containing monomers in the copolymer molecular chain can form hydrogen bonds through the hydroxyl groups, further improving the system's miscibility and effectively solving phase separation and aggregation problems. This avoids affecting the core optical indicators of the polarizer protective film itself, such as light transmittance, thereby meeting the stringent optical protection requirements of equipment.

[0025] For example, the weight parts of the quaternary ammonium salt monomer can be 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, etc. The weight parts of the first acrylate soft monomer can be 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, 26 parts, 27 parts, 28 parts, 29 parts, 30 parts, etc. The weight parts of the first acrylate hard monomer can be 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, 5.5 parts, 6 parts, 6.5 parts, 7 parts, 7.5 parts, 8 parts, etc. The weight parts of the hydroxyl-containing monomer can be 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, etc.

[0026] In some examples, the quaternary ammonium salt monomer is selected from at least one of methacryloyloxyethyltrimethylammonium chloride, methacryloyloxyethyltriethylammonium chloride, acryloyloxyethyltrimethylammonium chloride, and methacryloyloxyethyldimethylbenzylammonium chloride.

[0027] The aforementioned quaternary ammonium salt monomers are all polymerizable quaternary ammonium salt monomers. Their molecules simultaneously contain acrylate groups that can participate in the copolymerization reaction and positively charged quaternary ammonium salt conductive groups. After copolymerization, the quaternary ammonium salt cations are covalently fixed to the polymer backbone, fundamentally preventing the migration and precipitation of antistatic components and endowing the antistatic agent with long-lasting and stable antistatic properties. Furthermore, the quaternary ammonium salt monomers with different alkyl and benzyl substitutions can flexibly adjust the polarity and dispersibility of the copolymer, exhibiting good compatibility with acrylate systems. When used in combination with other monomers, they do not cause phase separation or fogging issues on the adhesive surface, ensuring the light transmittance of optical films and making them suitable for high-requirement optical applications such as polarizer protective films.

[0028] In some examples, the first acrylate soft monomer is selected from at least one of isooctyl acrylate, butyl acrylate, isobutyl acrylate, hexyl acrylate, isodecanyl acrylate, and tridecyl acrylate.

[0029] The aforementioned soft acrylate monomers all possess low glass transition temperatures. They contain acrylate groups and long alkyl flexible chains. The acrylate groups can participate in copolymerization reactions, anchoring the quaternary ammonium salt conductive groups to the adhesive network. The long alkyl flexible chains can avoid the problems of excessively rigid and brittle molecular chains caused by quaternary ammonium salts and the first hard acrylate monomers, allowing the antistatic agent to be fully miscible with other monomers in the adhesive copolymer without precipitation or delamination.

[0030] In some examples, the first acrylate hard monomer is selected from at least one of methyl methacrylate, methyl acrylate, ethyl (meth)acrylate, cyclohexyl (meth)acrylate, and isobornyl acrylate.

[0031] The aforementioned acrylate hard monomers all possess high glass transition temperatures. After copolymerization, they can moderately increase the rigidity of the antistatic agent's molecular chain, weaken the aggregation tendency of quaternary ammonium salt groups, and improve the compatibility of the antistatic agent with other monomers in the adhesive copolymer. Simultaneously, they tighten the molecular chain to bind the conductive groups of the quaternary ammonium salt, inhibiting ion migration and synergistically strengthening the long-lasting antistatic effect with the quaternary ammonium salt monomers.

[0032] In some examples, the hydroxyl-containing monomer is selected from at least one of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyethyl methacrylate, and hydroxypropyl methacrylate.

[0033] All of the aforementioned monomers contain hydroxyl groups, which form hydrogen bonds within the antistatic agent molecular chain, weakening the self-agglomeration of quaternary ammonium salt ions and ensuring the uniformity and transparency of the antistatic agent. Simultaneously, they impart numerous hydroxyl sites to the antistatic agent, allowing it to form intermolecular forces with various acrylate monomers used in the preparation of adhesive copolymers when subsequently added to the monomer system. This significantly improves the compatibility of the antistatic agent with various acrylate monomers, eliminating stratification and precipitation issues during copolymerization. Furthermore, the hydroxyl-containing monomers also contain acrylate groups, which can participate in the polymerization reaction and integrate into the antistatic agent molecular chain without migrating or precipitating.

[0034] On the other hand, embodiments of this application provide a method for preparing an antistatic agent, see [link to relevant documentation]. Figure 1 The preparation method includes: Step 101: Obtain a mixture containing quaternary ammonium salt monomer, first acrylate soft monomer, first acrylate hard monomer and hydroxyl-containing monomer.

[0035] Add quaternary ammonium salt monomer, first acrylate soft monomer, first acrylate hard monomer, hydroxyl-containing monomer and solvent to the reaction vessel, and stir with a mechanical stirrer to mix the components evenly to obtain a mixture.

[0036] The solvent may be selected from at least one of ethyl acetate, butyl acetate, methyl ethyl ketone, and toluene. For example, the solvent may be ethyl acetate, or a mixture of ethyl acetate and methyl ethyl ketone in a volume ratio of 3:1.

[0037] The solvents mentioned above have excellent solubility for quaternary ammonium salt monomers, soft monomers of first acrylate, hard monomers of first acrylate, and hydroxyl-containing monomers, which helps to form a uniform and transparent polymerization system and avoid problems such as monomer precipitation, system layering, and local gelation.

[0038] During the stirring process, nitrogen gas can be introduced into the mixture to remove oxygen from the mixture, and then step 102 can be performed.

[0039] The nitrogen introduction time can be set and changed as needed, and there is no specific limitation. For example, the nitrogen introduction time can be 20 min to 40 min. For example, the nitrogen introduction time can be 20 min, 25 min, 30 min, 35 min, 40 min, etc.

[0040] Step 102: Under the initiation of the initiator, the mixture undergoes a copolymerization reaction to obtain a copolymer solution.

[0041] Add an initiator to the mixture, then heat the system to 50℃~75℃ and stir the reaction under a nitrogen atmosphere for 6h~8h.

[0042] For example, the temperature after heating can be 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, etc. The reaction time can be 6h, 6.2h, 6.5h, 6.8h, 7h, 7.2h, 7.5h, 7.8h, 8h, etc.

[0043] The speed can be set and changed as needed, without specific limitations. For example, the speed can be 250rpm to 350rpm. Examples include 250rpm, 280rpm, 300rpm, 320rpm, and 350rpm.

[0044] The initiator may be selected from at least one of azobisisobutyronitrile (AIBN), azobisisoheptanenitrile, benzoyl peroxide, and di-tert-butyl peroxide.

[0045] The initiator has a mass fraction of 0.08% to 0.15%. The mass fraction of the initiator refers to the ratio of the mass of the initiator to the total mass of the quaternary ammonium salt monomer, the first acrylate soft monomer, the first acrylate hard monomer, and the hydroxyl-containing monomer.

[0046] For example, the mass fraction of the initiator can be 0.08%, 0.09%, 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, etc.

[0047] The above-mentioned initiators are free radical polymerization initiators, suitable for polymerization systems of quaternary ammonium salt monomers, soft and hard acrylate monomers and hydroxyl-containing monomers. They can stably decompose at a certain temperature to generate free radicals, effectively initiating monomer copolymerization reactions.

[0048] Step 103: Purify and dry the copolymer solution to obtain an antistatic agent.

[0049] The copolymer solution was placed in a rotary evaporator at a temperature of 40℃~60℃ and a vacuum degree of -0.08MPa~-0.1MPa to remove the solvent, yielding a concentrated solution. Precipitation purification was then performed using a precipitant: the concentrated solution was slowly added dropwise to the precipitant at a rate of 1 drop / s~2 drops / s while stirring, allowing the copolymer to fully precipitate and form a white flocculent precipitate. The precipitate was filtered, washed, and then placed in a vacuum drying oven at 45℃~55℃ and a vacuum degree of -0.08MPa~-0.1MPa for 8h~16h to obtain a quaternary ammonium salt type acrylate copolymer, i.e., an antistatic agent. The solid content of this antistatic agent is ≥98%.

[0050] The rotary evaporator can be configured with temperatures of 40℃, 42℃, 45℃, 48℃, 50℃, 52℃, 55℃, 58℃, and 60℃. Vacuum levels can be -0.08MPa, -0.085MPa, -0.09MPa, -0.095MPa, and -0.1MPa.

[0051] The precipitant may be selected from at least one of glacial ether, petroleum ether, n-hexane, and cyclohexane. For example, the precipitant may be glacial ether, or a mixture of glacial ether and n-hexane in a volume ratio of 1:1.

[0052] A precipitating agent can also be used to wash the precipitate to remove unreacted monomers and residual initiators.

[0053] The vacuum drying oven can be set to temperatures of 45℃, 48℃, 50℃, 52℃, and 55℃, and to vacuum levels of -0.08MPa, -0.085MPa, -0.09MPa, -0.095MPa, and -0.1MPa. Drying times can be 8h, 9h, 10h, 11h, 12h, 13h, 14h, 15h, and 16h.

[0054] In this embodiment, most of the solvent is first removed by rotary evaporation, then the copolymer is precipitated using a precipitant. Combined with dropwise addition, stirring, and multiple washing, small molecule impurities are thoroughly removed. Finally, vacuum drying is used to completely remove residual organic solvent, yielding a copolymer with high purity, no residue, and undamaged antistatic and optical properties. This one-step synthesis method for the antistatic agent is simple, yields good product, and is suitable for industrial production.

[0055] On the other hand, embodiments of this application provide a pressure-sensitive adhesive comprising the following components in parts by weight: 100 parts of adhesive copolymer, 0.05 to 0.15 parts of photoinitiator, and 1 to 2.5 parts of ionic liquid; The adhesive copolymer is composed of the following components in parts by weight: 1 to 3 parts of antistatic agent, 60 to 75 parts of soft monomer of second acrylate, 0 to 7 parts of hard monomer of second acrylate, 5 to 15 parts of hydroxyl-containing monomer, and 15 to 25 parts of monomer containing ether bond; The antistatic agent is the antistatic agent mentioned above.

[0056] The pressure-sensitive adhesive provided in this application embodiment is obtained by first copolymerizing an antistatic agent, a second acrylate soft monomer, a second acrylate hard monomer, a hydroxyl-containing monomer, and an ether-containing monomer to form an adhesive copolymer, and then compounding the adhesive copolymer, a photoinitiator, and an ionic liquid to obtain the pressure-sensitive adhesive. Based on the composition of the adhesive copolymer and the antistatic agent, it is known that the antistatic agent and the adhesive copolymer have good structural compatibility, and the antistatic agent is completely integrated into the molecular chain system of the adhesive copolymer through participation in the polymerization reaction, eliminating the risk of phase separation caused by physical mixing.

[0057] In addition to the adhesive copolymer, ionic liquids are also added during the formulation of pressure-sensitive adhesives. Ionic liquids not only provide a large number of free charge carriers due to their high degree of dissociation, but also form a "dual ion channel" with quaternary ammonium salt ions in the antistatic agent. The quaternary ammonium salt ions act as the basic conductive carriers to construct the backbone conductive network, while the imidazole ions dissociated from the ionic liquid fill the gaps in the backbone conductive network, significantly improving carrier migration efficiency. Furthermore, the vinyl or allyl groups in the ionic liquid can simultaneously participate in the photopolymerization reaction, also anchoring themselves in the adhesive layer in a covalent bond form, preventing their free diffusion and aggregation within the system.

[0058] For example, the weight parts of the photoinitiator can be 0.05 parts, 0.06 parts, 0.07 parts, 0.08 parts, 0.09 parts, 0.1 parts, 0.11 parts, 0.12 parts, 0.13 parts, 0.14 parts, 0.15 parts, etc. The weight parts of the ionic liquid can be 1 part, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, 1.9 parts, 2 parts, 2.1 parts, 2.2 parts, 2.3 parts, 2.4 parts, 2.5 parts, etc. The weight parts of the antistatic agent can be 1 part, 1.2 parts, 1.5 parts, 1.8 parts, 2 parts, 2.2 parts, 2.5 parts, 2.8 parts, 3 parts, etc. The weight parts of the second acrylate soft monomer can be 60 parts, 62 parts, 65 parts, 68 parts, 70 parts, 72 parts, 75 parts, etc. The weight parts of the second acrylate hard monomer can be 0, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, etc. The weight parts of the hydroxyl-containing monomer can be 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, etc. The weight parts of the ether-containing monomer can be 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, etc.

[0059] It should be noted that the weight percentages of the photoinitiator and ionic liquid mentioned above are determined based on the weight percentages of the adhesive copolymer. That is, when the weight percentage of the adhesive copolymer is 100 parts, the weight percentage of the photoinitiator is 0.05 to 0.15 parts, and the weight percentage of the ionic liquid is 1 to 2.5 parts. When the weight percentage of the adhesive copolymer changes, the weight percentages of the photoinitiator and ionic liquid are adjusted accordingly.

[0060] In some examples, the ionic liquid is selected from at least one of 1-vinyl-3-butylimidazolium bis(trifluoromethanesulfonyl)imide (VBIM-TFSI), 1-vinyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (VMIM-TFSI), 1-vinyl-3-hexylimidazolium bis(trifluoromethanesulfonyl)imide (VHIM-TFSI), 1-allyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (AMIM-TFSI), and 1-vinyl-3-butylimidazolium hexafluorophosphate (VBIM-PF6).

[0061] The above-mentioned ionic liquids are all imidazolium-based ionic liquids. These ionic liquids have extremely high dissociation and can form "dual ion channels" with quaternary ammonium salt ions in the system. At the same time, the ionic liquids contain vinyl or allyl groups, which can participate in UV polymerization and are covalently anchored in the adhesive layer without migration risk.

[0062] In some examples, the ether-containing monomer is selected from at least one of methoxyethyl acrylate, ethoxyethoxyethyl acrylate, ethoxymethacrylate, propoxyethyl acrylate, methoxyethoxyethyl methacrylate, diethylene glycol monoacrylate, polyethylene glycol methacrylate, polyethylene glycol acrylate, and polypropylene glycol methacrylate.

[0063] Among them, polyethylene glycol methacrylate has a number average molecular weight of 400, polyethylene glycol acrylate has a number average molecular weight of 400-600, and polypropylene glycol methacrylate has a number average molecular weight of 400-500.

[0064] The aforementioned ether-containing monomers contain polymerizable acrylate groups and flexible ether side chains. The acrylate groups can participate in UV copolymerization reactions, allowing the ether-containing monomers to be covalently anchored in the adhesive copolymer. Furthermore, the ether bonds possess excellent ion solubilization capabilities, enabling them to form complexes with quaternary ammonium salt conductive groups and ions in ionic liquids, constructing continuous ion transport channels, significantly improving ion migration efficiency, and synergistically enhancing the antistatic properties of the system.

[0065] In some examples, the second acrylate soft monomer is selected from at least one of isooctyl acrylate, butyl acrylate, isobutyl acrylate, isodecanyl acrylate, tridecyl acrylate, 2-ethylhexyl acrylate, and their isomers.

[0066] The aforementioned soft acrylate monomers have a low glass transition temperature and are the main copolymer components of the adhesive copolymer. Their long alkyl flexible chains impart excellent initial tack and substrate wettability to the adhesive layer, ensuring a tight bond between the protective film and the polarizer. Furthermore, they can balance the high rigidity provided by the second hard acrylate monomer, improving the adhesive layer's bending resistance and impact resistance.

[0067] It should be noted that the second acrylate soft monomer can be the same as or different from the first acrylate soft monomer; no specific limitation is made. Although both the first and second acrylate soft monomers are acrylate soft monomers with low glass transition temperatures, they exist in different systems, and therefore their functions differ somewhat. The first acrylate soft monomer mainly improves the dispersibility and copolymerizability of antistatic agents, and its dosage is not high. The second acrylate soft monomer, on the other hand, primarily functions as an adhesive in pressure-sensitive adhesives, directly determining the initial tack and peel strength, and its dosage is relatively high, making it a core component determining the pressure-sensitive properties.

[0068] In some examples, the second acrylate hard monomer is selected from at least one of methyl methacrylate, isobornyl methacrylate, methyl acrylate, ethyl acrylate, tert-butyl methacrylate, and cyclohexyl methacrylate.

[0069] The aforementioned acrylate hard monomers all have high glass transition temperatures. As important copolymer components in adhesive copolymers, they can significantly improve the cohesive strength and surface hardness of the adhesive layer, enhance the scratch and wear resistance of the protective film, and prevent the polarizer from being scratched during production and transportation. At the same time, they can also balance the high adhesion brought by the second acrylate soft monomer, precisely control the peeling force, peel off without residue, and without damaging the polarizer.

[0070] It should be noted that the second acrylate hard monomer and the first acrylate hard monomer can be the same or different; no specific limitation is made. Although both the second and first acrylate hard monomers are acrylate hard monomers with high glass transition temperatures, they exist in different systems, and therefore their functions differ somewhat. The first acrylate hard monomer in the antistatic agent mainly improves the compatibility between the antistatic agent and other components in the adhesive copolymer, while preventing the precipitation of conductive ions. The second acrylate hard monomer in the adhesive copolymer mainly enhances the scratch and abrasion resistance of the adhesive layer, preventing scratches on the polarizer.

[0071] In some examples, the hydroxyl-containing monomer in the adhesive copolymer is selected from at least one of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyethyl methacrylate, and hydroxypropyl methacrylate.

[0072] The hydroxyl-containing monomers in the adhesive copolymer and the hydroxyl-containing monomers in the antistatic agent can be the same or different, and there is no specific limitation on this.

[0073] The hydroxyl-containing monomers in the adhesive copolymer can construct a high-density hydrogen bond network, which on the one hand enhances the cohesive strength of the adhesive layer, precisely controls the peel force, and effectively avoids peel residue; on the other hand, it improves the interfacial adhesion between the adhesive layer and the substrate and polarizer, preventing the protective film from peeling off after long-term adhesion. Simultaneously, the hydroxyl groups can participate in the photopolymerization reaction, improving the integrity of the adhesive layer curing, reducing curing shrinkage stress, and enhancing the dimensional stability and resistance to damp heat aging of the protective film. Furthermore, the aforementioned hydroxyl-containing monomers also contain acrylate groups, which participate in the copolymerization reaction during the preparation of the adhesive copolymer, stabilizing the hydroxyl groups covalently on the adhesive copolymer molecular chain and preventing migration and precipitation. In addition, the acrylate groups are structurally compatible with other acrylate monomers used in the preparation of the adhesive copolymer, allowing for polymerization to obtain a structurally uniform adhesive copolymer, reducing phase separation, and ensuring the optical transparency of the adhesive layer.

[0074] In some examples, the photoinitiator is selected from at least one of the following: trimethylbenzoyl-diphenylphosphine oxide (TPO), 1-hydroxycyclohexylphenyl ketone (184), 2-hydroxy-2-methyl-1-phenyl-1-propanone (1173), 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO-L), benzophenone (BP), and triethanolamine (TEA).

[0075] When the photoinitiator is selected from the compound system of benzophenone (BP) and triethanolamine (TEA), the mass ratio of benzophenone (BP) to triethanolamine (TEA) can be 2:1.

[0076] The aforementioned photoinitiator can efficiently generate active free radicals under ultraviolet light irradiation, fully stimulating the cross-linking of acrylate groups on the side chains of the adhesive copolymer and vinyl groups in the ionic liquid, constructing a dense and uniform three-dimensional adhesive network, and significantly improving the cohesive strength of the adhesive layer.

[0077] On the other hand, embodiments of this application provide a method for preparing a pressure-sensitive adhesive, see [link to relevant documentation]. Figure 2 The preparation method includes: Step 201: Prepare adhesive copolymer.

[0078] This step can be achieved through the following steps (1) to (2), including: (1) Mix the antistatic agent, the second acrylate soft monomer, the second acrylate hard monomer, the hydroxyl-containing monomer, the ether-containing monomer and the photoinitiator to obtain a mixture.

[0079] In this step, the photoinitiator is present in a weight ratio of 0.2 to 0.6 parts. For example, the weight ratio of the photoinitiator can be 0.2, 0.3, 0.4, 0.5, 0.6, etc.

[0080] The photoinitiator can be selected from at least one of the following: a compound system of TPO, 184, 1173, TPO-L, BP and TEA.

[0081] The aforementioned photoinitiator can initiate a copolymerization reaction of the antistatic agent, the second acrylate soft monomer, the second acrylate hard monomer, the hydroxyl-containing monomer, and the ether-containing monomer to obtain an adhesive copolymer.

[0082] An antistatic agent, a soft monomer of the second acrylate, a hard monomer of the second acrylate, a hydroxyl-containing monomer, an ether-containing monomer, and a photoinitiator are added to a reaction vessel. The components are then mixed thoroughly using a mechanical stirrer to obtain a homogeneous mixture. Nitrogen gas can be introduced during stirring to remove nitrogen fumes.

[0083] The nitrogen introduction time can be set and changed as needed, and there is no specific limitation. For example, the nitrogen introduction time can be 20 min to 40 min. For example, the nitrogen introduction time can be 20 min, 25 min, 30 min, 35 min, 40 min, etc.

[0084] During the reaction, the reaction vessel can be placed in a specific reaction apparatus to avoid interference from external light sources.

[0085] (2) The mixture is irradiated under an ultraviolet light source to initiate a copolymerization reaction, and an adhesive copolymer is obtained.

[0086] The copolymerization reaction was initiated by irradiating the mixture with ultraviolet light. The system temperature was monitored in real time during the reaction. When the temperature rose to 30℃~60℃, the ultraviolet light was turned off to complete the reaction. After cooling to room temperature, the adhesive copolymer was obtained.

[0087] The wavelength of the ultraviolet lamp can be 365nm, 395nm, 405nm, etc., without specific limitations.

[0088] The rated power of a UV lamp can be 15W to 30W. For example, the rated power of a UV lamp can be 15W, 18W, 20W, 22W, 25W, 28W, 30W, etc.

[0089] The distance between the UV lamp and the reaction vessel can be 15cm to 25cm. For example, the distance between the UV lamp and the reaction vessel can be 15cm, 18cm, 20cm, 22cm, 25cm, etc.

[0090] The temperature that the system can be raised to can be 30℃, 35℃, 40℃, 45℃, 50℃, 55℃, 60℃, etc.

[0091] It should be noted that after obtaining the adhesive copolymer, it can be transferred to a light-proof container for storage. When preparing the pressure-sensitive adhesive, the appropriate amount of adhesive copolymer can be taken out.

[0092] Step 202: Mix the adhesive copolymer, photoinitiator and ionic liquid to obtain a pressure-sensitive adhesive.

[0093] A pressure-sensitive adhesive is prepared by uniformly mixing an adhesive copolymer, a photoinitiator, and an ionic liquid. This pressure-sensitive adhesive is a liquid. Upon irradiation with ultraviolet light, the pressure-sensitive adhesive cures to form an adhesive layer.

[0094] On the other hand, embodiments of this application provide a polarizer protective film, which includes: a substrate, an adhesive layer, and a release film, wherein the adhesive layer is located between the substrate and the release film.

[0095] The adhesive layer is formed by light curing a pressure-sensitive adhesive, which is the pressure-sensitive adhesive mentioned above.

[0096] In this embodiment, after obtaining the pressure-sensitive adhesive, it can be applied to the surface of the substrate by a slot coating process to form a three-layer structure of "substrate-adhesive-release film". Under ultraviolet light irradiation, the adhesive is cured to obtain an adhesive layer, forming a three-layer structure of "substrate-adhesive layer-release film", thereby obtaining a polarizer protective film.

[0097] Among them, the light energy can be 250mJ / cm. 2 ~350mJ / cm 2 For example, the light energy can be 250 mJ / cm². 2 280mJ / cm 2 300mJ / cm 2 320mJ / cm 2 350mJ / cm 2 wait.

[0098] In some examples, the thickness of the adhesive layer is 15μm to 25μm.

[0099] For example, the thickness of the adhesive layer can be 15μm, 16μm, 17μm, 18μm, 19μm, 20μm, 21μm, 22μm, 23μm, 24μm, 25μm, etc. Optionally, the thickness of the adhesive layer is 20μm.

[0100] When the adhesive layer thickness is less than 15 μm, the total amount of adhesive is insufficient, making it impossible to construct continuous ion transport channels, resulting in poor antistatic performance and a tendency for insufficient adhesive during coating. When the adhesive layer thickness is greater than 25 μm, incomplete curing is likely, leading to easy film curling and peeling with residual adhesive. Therefore, controlling the adhesive layer thickness between 15 μm and 25 μm allows the adhesive layer to possess long-lasting antistatic properties, suitable peel strength, and high light transmittance and low haze optical characteristics.

[0101] In some examples, the thickness of the substrate is 45μm to 55μm, and the thickness of the release film is 45μm to 55μm.

[0102] For example, the thickness of the substrate can be 45μm, 46μm, 47μm, 48μm, 49μm, 50μm, 51μm, 52μm, 53μm, 54μm, 55μm, etc. The thickness of the release film can be 45μm, 46μm, 47μm, 48μm, 49μm, 50μm, 51μm, 52μm, 53μm, 54μm, 55μm, etc.

[0103] The substrate thickness is between 45μm and 55μm, which combines toughness and flexibility, making it less prone to stretching and wrinkling during high-speed slot coating and UV curing and winding, resulting in high processing stability. The release film thickness is between 45μm and 55μm, which can evenly distribute the winding pressure of the roll material and avoid indentation and adhesive seepage defects in the adhesive layer.

[0104] In some examples, the substrate is selected from at least one of polyethylene terephthalate (PET), polycarbonate (PC), and polymethyl methacrylate (PMMA). Optionally, the substrate is a PET substrate.

[0105] The release film is selected from at least one of PET, PEN, and polymethylpentene (TPX). Optionally, the release film is selected from PET.

[0106] See Figure 3 , Figure 3 This is a schematic diagram of the structure of a polarizer protective film provided in an embodiment of this application. From... Figure 3 As can be seen from the image, the polarizer protective film includes a PET substrate 301, an adhesive layer 302, and a PET release film 303, with the adhesive layer 302 located between the PET substrate 301 and the PET release film 303.

[0107] The polarizer protective film prepared by the pressure-sensitive adhesive provided in this application is used for polarizer performance testing and protection during shipment. It has a light transmittance of over 94%, haze controlled within 0.3%, low peel strength, no adhesive residue, low VOC (Volatile Organic Compounds) emissions, excellent weather resistance, and outstanding performance in balancing antistatic durability and optical properties.

[0108] On the other hand, embodiments of this application provide a display device, which includes: a display panel, a polarizer disposed on the display panel, and a polarizer protective film attached to the surface of the polarizer, wherein the polarizer protective film is the polarizer protective film mentioned above.

[0109] When applying the polarizer protective film to the polarizer surface, the release film is first removed, and then the adhesive layer is applied to the polarizer surface to provide protection for the polarizer.

[0110] See Figure 4 , Figure 4 This is a schematic diagram of a structure for attaching a protective film to a polarizer, as provided in an embodiment of this application. Figure 4 It includes: PET substrate 401, adhesive layer 402 and polarizer 403. Before the adhesive layer 402 is bonded to the polarizer 403, the release film needs to be removed first, and then the adhesive layer 402 is bonded to the surface of the polarizer 403.

[0111] For example, the display device includes, but is not limited to: OLED (Organic Light Emission Diodes) TVs, tablets, in-vehicle displays, MP3 players, smartwatches, fitness trackers, virtual reality (VR) headsets, augmented reality (AR) glasses, etc.

[0112] In summary, this application achieves breakthroughs in multiple dimensions, including core performance, manufacturing process, and application compatibility, through innovative designs of "covalent anchoring of antistatic agents" and "synergistic conduction of dual ions." Compared with traditional technical solutions, it has the following unique and practical advantages, as detailed below: (1) The antistatic performance has achieved a dual breakthrough of "long-lasting and high-efficiency", solving the core pain point in the industry. In related technologies, antistatic adhesives generally employ additive-type antistatic agents. These agents cannot participate in the polymerization reaction of the adhesive system and can only be dispersed within the system through physical mixing. This design leads to two key problems: First, the antistatic agent easily migrates to the adhesive surface or is lost over time, causing a rapid decline in antistatic performance. Typically, the surface resistance increases significantly after 1-3 months of use, failing to meet long-term usage requirements. Second, the antistatic agent struggles to build a stable conductive network within the system, relying only on surface-adsorbed moisture to form temporary conductive channels. This results in low antistatic efficiency and is highly susceptible to environmental humidity, essentially losing its antistatic effect in dry environments.

[0113] This application specifically addresses the aforementioned problems: Firstly, the independently synthesized quaternary ammonium salt acrylate copolymer, as a long-lasting antistatic agent, contains acrylate groups in its molecular structure that can deeply participate in the UV polymerization reaction, firmly anchoring to the adhesive copolymer molecular chain through covalent bonds. This effectively solves the problems of migration and precipitation of antistatic components, achieving long-lasting antistatic performance. Actual testing shows that the pressure-sensitive adhesive using this technology maintains a stable surface resistivity of 10 Ω after 12 months of continuous use under normal temperature and humidity conditions. 6 -10 8 The superior antistatic range of Ω far surpasses the performance degradation of existing additive-based products, which exceeds an order of magnitude within three months. Furthermore, by adding an appropriate amount of ionic liquid, it not only provides a large number of free charge carriers due to its high dissociation properties, but also forms a "dual-ion channel" with quaternary ammonium salt ions—quaternary ammonium salt ions serve as the basic conductive carrier to construct the backbone conductive network, while imidazole ions dissociated from the ionic liquid fill the network gaps, significantly improving carrier migration efficiency. This synergistic effect allows the surface resistivity of the adhesive layer to rapidly decrease to 10 Ω. 6 -10 8 Ω effectively overcomes the shortcomings of traditional technologies, such as low antistatic efficiency and environmental constraints.

[0114] (2) Ensure the high optical performance of the adhesive layer, while solving the compatibility problem between it and the antistatic agent. In related technologies, the compatibility between additive antistatic agents and pressure-sensitive adhesive systems is generally poor, easily leading to problems such as phase separation and agglomeration. This directly results in surface haze and reduced light transmittance, failing to meet the stringent requirements of high-end optical fields such as polarizer protective films and optical lenses, which demand adhesives with a transmittance of ≥92% and a haze of ≤0.5%. Furthermore, after migrating to the adhesive surface, the antistatic agent forms an uneven film, further compromising the optical smoothness of the adhesive layer and affecting the imaging quality or visual effect of subsequent products.

[0115] This application fundamentally solves the compatibility problem through a covalent anchoring design: the quaternary ammonium acrylate copolymer itself has good structural compatibility with the UV-active monomer, and it integrates well into the adhesive copolymer molecular chain system through participation in the polymerization reaction, eliminating the risk of phase separation caused by physical mixing; the vinyl or propylene groups in the ionic liquid can simultaneously participate in UV polymerization, also anchored in the adhesive layer in the form of covalent bonds, avoiding their free diffusion and aggregation within the system. The pressure-sensitive adhesive prepared by this application can achieve a light transmittance of over 94%, with haze controlled within 0.3%, and the adhesive surface is smooth and free from any fogging or frosting, fully meeting the optical performance requirements of high-end optical products such as polarizer protective films. In addition, since there is no risk of migration of the antistatic component, the interface between the adhesive layer and the adhered substrate is more tightly bonded, and interface peeling will not occur due to the precipitation of antistatic agent, further ensuring the long-term stability of the optical components.

[0116] (3) Expand the high-end application scenarios of antistatic adhesives and break through the limitations of the existing technology's applicability. In related technologies, antistatic adhesives suffer from problems such as short-lasting antistatic properties, poor optical performance, and susceptibility to adhesive layer defects. These limitations restrict their application to low-performance scenarios like general packaging and electronic component housings, preventing their entry into high-end optical fields such as polarizer protective films, mobile phone screen modules, and optical lenses. In these high-end applications, adhesives not only require long-term stable antistatic properties but also demanding conditions such as high light transmittance, low haze, and no component migration. Related technologies struggle to simultaneously meet these requirements, creating a significant application limitation.

[0117] This application successfully breaks through this application boundary through multi-performance synergistic optimization: its combined long-lasting antistatic properties, excellent optical performance, and stable interfacial adhesion match the usage requirements of polarizer protective films—effectively preventing electrostatic adsorption of dust and impurities from damaging the optical performance of polarizers, while ensuring the light transmission effect and imaging quality of polarizers. Furthermore, this pressure-sensitive adhesive can also be extended to scenarios such as screen module bonding in mobile phones, computers, and other electronic products, and optical lens fixing. Compared to the limitations of related technologies, which are mostly used in low-to-mid-range scenarios, this application significantly increases the added value of products and opens up new market space for enterprises.

[0118] (4) Improve the overall stability of the adhesive layer and extend the service life of the product. Additive antistatic agents in related technologies are prone to migration, which not only leads to a decrease in antistatic performance but also damages the cross-linked structure of the adhesive layer during migration, causing problems such as cracking and embrittlement, thus reducing the adhesive strength and service life of the adhesive. Some antistatic agents can also react chemically with other components in the adhesive system, producing harmful substances that further affect the stability and safety of the adhesive layer. In harsh environments such as high temperature and high humidity, this performance degradation and structural damage will be more pronounced, severely limiting the application of the product in complex environments.

[0119] This application effectively enhances the overall stability of the adhesive layer through a covalent anchoring design: both the quaternary ammonium salt acrylate copolymer and the ionic liquid are anchored via covalent bonds, preventing migration due to environmental changes and ensuring the integrity of the cross-linked structure of the adhesive layer. Environmental aging tests show that after aging at 85℃ and 85% relative humidity for 1000 hours, the yellowing index (Δb) of this pressure-sensitive adhesive is [data missing]. The change is less than 2%, and there is no yellowing, bubbling, cracking, or embrittlement in the appearance. At the same time, since the antistatic component is completely compatible with the system, it will not produce harmful chemical reactions, making it safer to use and suitable for various complex environments such as high and low temperatures and high humidity.

[0120] In summary, this application, through innovative technical design, specifically addresses the core pain points of current antistatic adhesives, such as short-lasting antistatic performance, poor optical performance, and limited application, demonstrating strong technological disruptiveness and broad market application prospects.

[0121] Exemplary embodiments of this application will now be described in more detail. While exemplary embodiments of this application are described below, it should be understood that this application may be implemented in various forms and should not be limited to the embodiments set forth herein.

[0122] Synthesis example The synthesis example provides an antistatic agent prepared by the following method: Step 1: Weigh a certain mass of the reactants (DMC, 2-EHA, methyl methacrylate, MMA, HEA) in a 500 mL beaker at a mass ratio of 20:23:5:1. Add 250 mL of ethyl acetate to the beaker and mix the components thoroughly using a mechanical stirrer while purging with nitrogen for 30 min. Then add 0.1% (w / w) of azobisisobutyronitrile (AIBN), heat to 60 °C, and stir at 300 rpm for 6-8 h under a nitrogen atmosphere. After the reaction is complete, a copolymer solution is obtained.

[0123] Step 2: Place the copolymer solution (solid content approximately 60%) in a rotary evaporator at a temperature of 45℃~50℃ and a vacuum of -0.09MPa~-0.1MPs to remove most of the ethyl acetate, obtaining a viscous concentrate. Use glacial ether as a precipitant for precipitation purification: slowly add 10 times the volume of glacial ether dropwise at a rate of 1 drop / s~2 drops / s while stirring at 300 rpm, allowing the polymer to fully precipitate and form a white flocculent precipitate. Filter the precipitate and wash it 2~3 times with glacial ether to remove unreacted monomers such as DMC and MMA, as well as residual AIBN. Finally, place the washed precipitate in a vacuum drying oven and dry it at 50℃ and a vacuum of -0.09MPa for 12 hours to obtain the antistatic agent (solid content ≥98%).

[0124] Example 1 Example 1 provides a pressure-sensitive adhesive, which is prepared by the following method: Step 1: Add 2 parts of antistatic agent, 60 parts of isooctyl acrylate, 10 parts of hydroxyethyl acrylate, 5 parts of methyl methacrylate, 23 parts of methoxyethyl acrylate, and 0.3 parts of photoinitiator TPO to a clean, dry reactor. Mix all components thoroughly using a mechanical stirrer while simultaneously purging with nitrogen for 30 minutes. Place the reactor in a specific reaction apparatus to avoid interference from external light sources during the reaction. The UV lamp used in the reaction has a rated power of 20W and a wavelength of 365nm, with a distance of 20cm between the UV lamp and the reactor. Monitor the system temperature in real time during the reaction. Once the temperature reaches 30℃~40℃, turn off the UV lamp to complete the reaction. After the system cools to room temperature, the adhesive copolymer is obtained. Transfer the adhesive copolymer to a light-proof container for storage.

[0125] The antistatic agent is the same as the antistatic agent synthesized in the above synthesis example.

[0126] Step 2: Weigh 100 parts of adhesive copolymer, 0.1 parts of photoinitiator TPO and 2 parts of VBIM-TFSI, mix them evenly and degas to obtain pressure-sensitive adhesive.

[0127] Example 2 Example 2 provides a pressure-sensitive adhesive, which differs from Example 1 in that the weight of VBIM-TFSI is 1.5 parts, while the other components and their amounts are the same.

[0128] Example 3 Example 3 provides a pressure-sensitive adhesive, which differs from Example 1 in that the antistatic agent in the adhesive copolymer is 2.5 parts by weight, the methoxyethyl acrylate is 22.5 parts by weight, and the remaining composition and dosage are the same as in Example 1.

[0129] Example 4 Example 4 provides a pressure-sensitive adhesive that differs from Example 1 in that the antistatic agent has 2.5 parts by weight, the methoxyethyl acrylate has 22.5 parts by weight, and methyl methacrylate is replaced with isobornyl methacrylate, which still has 5 parts by weight. The remaining components and their amounts are the same as in Example 1.

[0130] Example 5 Example 5 provides a pressure-sensitive adhesive, which differs from Example 1 in that the antistatic agent is 2.5 parts by weight, 23 parts of methoxyethyl acrylate is replaced with 22.5 parts of ethoxyethoxyethyl acrylate, and methyl methacrylate is replaced with isobornyl methacrylate, with the weight still being 5 parts. The remaining components and their amounts are the same as in Example 1.

[0131] Example 6 Example 6 provides a pressure-sensitive adhesive that differs from Example 1 in that the antistatic agent is 2.5 parts by weight, isooctyl acrylate is 70 parts by weight, methyl methacrylate is 0 parts by weight, and 23 parts of methoxyethyl acrylate are replaced with 17.5 parts of polyethylene glycol methacrylate (Mn=400). The remaining components and amounts are the same as in Example 1.

[0132] Example 7 Example 7 provides a pressure-sensitive adhesive, which differs from Example 6 in that the photoinitiator TPO is 0.5 parts by weight, while the remaining components and amounts are the same as in Example 6.

[0133] Comparative Example 1 Comparative Example 1 provides a pressure-sensitive adhesive that differs from Example 1 in that it comprises only 100 parts of adhesive copolymer and 0.1 parts of photoinitiator TPO, excluding VBIM-TFSI, while the remaining components and amounts are the same as in Example 1.

[0134] Comparative Example 2 Comparative Example 2 provides a pressure-sensitive adhesive that differs from Example 1 in that the weight of VBIM-TFSI is 3 parts, while the remaining components and amounts are the same as in Example 1.

[0135] Comparative Example 3 Comparative Example 3 provides a pressure-sensitive adhesive that differs from Example 7 in that the adhesive copolymer does not include an antistatic agent, while the remaining components and amounts are the same as in Example 7.

[0136] Comparative Example 4 Comparative Example 4 provides a pressure-sensitive adhesive that differs from Example 7 in that the antistatic agent in the adhesive copolymer is 3.5 parts by weight.

[0137] For the pressure-sensitive adhesives provided in Examples 1 to 7 and Comparative Examples 1 to 4, polarizer protective films can be prepared in the following manner: Pressure-sensitive adhesive is applied using a slit-type coating method to form a three-layer structure of "PET substrate - adhesive - release film". After curing by UV light, the adhesive is then cured, resulting in the three-layer structure of "PET substrate - adhesive layer - release film", which is the polarizing protective film. The light energy is 300 mJ / cm². 2 The thickness of both the substrate and the release film is 50 μm, and the thickness of the adhesive layer is 20 μm.

[0138] Next, the polarizer protective films corresponding to Examples 1 to 7 and Comparative Examples 1 to 4 were tested. The relevant test items are shown below: (1) 180° peel force test The polarizer protective film was cut to a size of 23mm × 150mm, the release film was removed, and the adhesive layer of the polarizer protective film was tightly adhered to the polarizer. It was then left to stand for 24 hours at 23±1℃ and 55±5%RH. The tensile testing was conducted using an INSTRON 3665 tensile testing machine. The low-speed peeling speed was 300mm / min, and the high-speed peeling speed was 3000mm / min.

[0139] (2) Film peeling static voltage test The polarizer protective film was cut into 100mm × 70mm pieces, the release liner was removed, and the adhesive layer of the protective film was tightly adhered to the polarizer. It was then left to stand for 24 hours at 23±1℃ and 55±5%RH. The tensile testing machine used was an FMX-004 model. The tearing speed was 3000mm / min.

[0140] (3) Water contact angle test Before testing, the polarizer protective film was left to stand for 2 hours at 23±1℃ and 55±5%RH. The protective film was then cut into 200mm×200mm pieces, flattened, and fixed onto the measuring instrument platform. The release film was removed, and a predetermined volume of ionized water was slowly dripped onto the sample surface using a microsyringe. The water contact angle measuring instrument used in the test had a superhydrophobic needle diameter of 0.25mm.

[0141] (4) Surface resistance test Before testing, the polarizer protective film was left to stand for 2 hours at 23±1℃ and 55±5%RH. The protective film was then cut into 100mm×100mm pieces, the release film was removed, and the film was flattened and fixed on the measuring instrument platform. A specified voltage was applied to the adhesive layer surface, and the surface leakage current was measured. The surface resistance (unit: Ω) was calculated according to Ohm's law. The high-resistance meter used in the test had a measurement range of 10. 4 ~10 18 Ω.

[0142] (5) Weather resistance test Remove the release film from the polarizer protective film and firmly adhere the adhesive layer to the polarizer. Test conditions: high temperature (80℃, 240h / 500h), high temperature and high humidity (60℃, 90%RH, 240h / 500h). Observe whether bubbling, fogging, yellowing, peeling, or other phenomena occur.

[0143] The test results are shown in Table 1.

[0144]

[0145] Note:" " " indicates no residue, "▲" indicates residue, "√" indicates no bubbling, fogging, yellowing, or peeling, and "×" indicates one or more of these phenomena.

[0146] A comparison of Examples 1, 2, Comparative Example 1, and Comparative Example 2 reveals that the addition and dosage of the ionic liquid VBIM-TFSI significantly affect the antistatic properties, peel compatibility, and weather resistance of the polarizer protective film. The synergistic effect of the ionic liquid and the antistatic agent is the core of this application's technical solution: the ionic liquid not only significantly enhances antistatic properties and durability through "dual ion channels," but also optimizes the flexibility of the adhesive layer to reduce peel force, while simultaneously ensuring weather resistance through covalent anchoring.

[0147] The core optimization value of polyethylene glycol methacrylate in polarizer protective film was verified by comparing Examples 5 and 6. Its polyether segments have good solvation effect and flexible adjustment function for ions, achieving a synergistic improvement in antistatic performance, peel adaptability and stability.

[0148] Comparative Examples 6 and 7 show that appropriately increasing the amount of photoinitiator TPO can optimize performance. With an appropriate increase in the amount of photoinitiator TPO, the low molecular weight polymer chains move more freely, ions are less likely to be encapsulated, and migration paths are smoother.

[0149] By comparing Example 7 with Comparative Example 3, it can be seen that relying solely on the single antistatic component of ionic liquid VBIM-TFSI has limited cross-linking points with the molecular chains of the adhesive layer, and lacks the "synergistic anchoring" effect of the antistatic agent on VBIM-TFSI. Under high temperature and high humidity conditions, the movement of the molecular chains of the adhesive layer intensifies, and the VBIM-TFSI that is not firmly anchored is prone to migration and precipitation.

[0150] Comparing Example 7 and Comparative Example 4, it can be seen that increasing the amount of antistatic agent to 3.5 parts did not improve the overall performance of the pressure-sensitive adhesive. Instead, problems such as significantly increased peel strength, residual adhesive, and failure of weather resistance appeared. This is because excessive antistatic agent exceeds the compatibility limit of the system, destroying the uniformity and cohesive strength of the cross-linked network of the adhesive layer. At the same time, it causes the antistatic components to agglomerate and separate, failing to form a continuous and stable conductive path on the adhesive surface. In addition, excessive polar quaternary ammonium salt components weaken their synergistic effect with the main adhesive, thus reducing the moisture and heat resistance of the adhesive layer. This makes it more prone to phase interface defects in high temperature and high humidity environments, resulting in poor weather resistance.

[0151] The above description is only for the purpose of enabling those skilled in the art to understand the technical solution of this application, and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An antistatic agent, characterized in that, The antistatic agent is copolymerized from the following monomers in parts by weight: 15-25 parts of quaternary ammonium salt monomer, 20-30 parts of soft monomer of first acrylate, 3-8 parts of hard monomer of first acrylate, and 1-5 parts of hydroxyl-containing monomer.

2. The antistatic agent according to claim 1, characterized in that, The quaternary ammonium salt monomer is selected from at least one of methacryloyloxyethyltrimethylammonium chloride, methacryloyloxyethyltriethylammonium chloride, and methacryloyloxyethyldimethylbenzylammonium chloride.

3. The antistatic agent according to claim 1, characterized in that, The first acrylate soft monomer is selected from at least one of isooctyl acrylate, butyl acrylate, isobutyl acrylate, hexyl acrylate, isodecanyl acrylate, and tridecyl acrylate.

4. The antistatic agent according to claim 1, characterized in that, The first acrylate hard monomer is selected from at least one of methyl methacrylate, methyl acrylate, ethyl methacrylate, cyclohexyl methacrylate, and isobornyl acrylate.

5. The antistatic agent according to claim 1, characterized in that, The hydroxyl-containing monomer is selected from at least one of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyethyl methacrylate, and hydroxypropyl methacrylate.

6. A method for preparing an antistatic agent, characterized in that, The antistatic agent is as described in any one of claims 1 to 5, and the preparation method comprises: Obtain a mixture comprising a quaternary ammonium salt monomer, a first acrylate soft monomer, a first acrylate hard monomer, and a hydroxyl-containing monomer; The mixture is subjected to a copolymerization reaction initiated by an initiator to obtain a copolymer solution; The copolymer solution was purified and dried to obtain the antistatic agent.

7. A pressure-sensitive adhesive, characterized in that, The pressure-sensitive adhesive comprises the following components in parts by weight: 100 parts of adhesive copolymer, 0.05 to 0.15 parts of photoinitiator, and 1 to 2.5 parts of ionic liquid; The adhesive copolymer is copolymerized from the following components in parts by weight: 1 to 3 parts of antistatic agent, 60 to 75 parts of soft monomer of second acrylate, 0 to 7 parts of hard monomer of second acrylate, 5 to 15 parts of hydroxyl-containing monomer, and 15 to 25 parts of monomer containing ether bond; The antistatic agent is as described in any one of claims 1 to 5 or as described in claim 6.

8. The pressure-sensitive adhesive according to claim 7, characterized in that, The ionic liquid is selected from at least one of 1-vinyl-3-butylimidazolium bis(trifluoromethanesulfonyl)imide, 1-vinyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-vinyl-3-hexylimidazolium bis(trifluoromethanesulfonyl)imide, 1-allyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, and 1-vinyl-3-butylimidazolium hexafluorophosphate.

9. The pressure-sensitive adhesive according to claim 7, characterized in that, The ether-containing monomer is selected from at least one of methoxyethyl acrylate, ethoxyethoxyethyl acrylate, ethoxymethacrylate, propoxyethyl acrylate, methoxyethoxyethyl methacrylate, diethylene glycol monoacrylate, polyethylene glycol methacrylate, polyethylene glycol acrylate, and polypropylene glycol methacrylate.

10. The pressure-sensitive adhesive according to claim 7, characterized in that, The second acrylate soft monomer is selected from at least one of isooctyl acrylate, butyl acrylate, isobutyl acrylate, isodecanyl acrylate, tridecyl acrylate, 2-ethylhexyl acrylate and their isomers.

11. The pressure-sensitive adhesive according to claim 7, characterized in that, The second acrylate hard monomer is selected from at least one of methyl methacrylate, isobornyl methacrylate, methyl acrylate, ethyl acrylate, tert-butyl methacrylate, and cyclohexyl methacrylate.

12. A method for preparing a pressure-sensitive adhesive, characterized in that, The pressure-sensitive adhesive is as described in any one of claims 7 to 11, and the preparation method comprises: Preparation of adhesive copolymers; The pressure-sensitive adhesive is obtained by mixing the adhesive copolymer, photoinitiator and ionic liquid.

13. The preparation method according to claim 12, characterized in that, The preparation of the adhesive copolymer includes: An antistatic agent, a second acrylate soft monomer, a second acrylate hard monomer, a hydroxyl-containing monomer, an ether-containing monomer, and a photoinitiator are mixed to obtain a mixture. The mixture is irradiated under an ultraviolet light source to initiate a copolymerization reaction, thereby obtaining the adhesive copolymer.

14. A polarizer protective film, characterized in that, The polarizer protective film includes: a substrate, an adhesive layer, and a release film, wherein the adhesive layer is located between the substrate and the release film; The adhesive layer is formed by light curing a pressure-sensitive adhesive, wherein the pressure-sensitive adhesive is as described in any one of claims 7 to 11 or as described in any one of claims 12 to 13.

15. A display device, characterized in that, The display device includes: a display panel, a polarizer disposed on the display panel, and a polarizer protective film adhered to the surface of the polarizer, wherein the polarizer protective film is as described in claim 14.

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