Silicone pressure-sensitive adhesive composition, adhesive film, and protective film for ar film

Abstract

This invention discloses an organosilicon pressure-sensitive adhesive composition, an adhesive film, and a protective film for AR films. The composition, by weight, comprises: 85-95 parts of a first MQ base adhesive, 5-15 parts of a second MQ base adhesive, 0.8-1.5 parts of a platinum catalyst, 0.5-1.2 parts of an organosilicon crosslinking agent, 0.3-0.5 parts of an antioxidant, 60-100 parts of an organic solvent, 0.1-0.3 parts of a silane coupling agent, 0.03-0.08 parts of a leveling agent, 0.02-0.05 parts of a defoamer, 0.1-0.2 parts of a chelating agent, 2.0-3.5 parts of MQ anchoring silicone resin, and 0.18-0.3 parts of a silicone-modified HALS additive. Both the first and second MQ base adhesives contain MQ silicone resin and vinyl-terminated polysiloxane, with the first MQ base adhesive having a higher vinyl content than the second MQ base adhesive. This invention employs a dual-MQ base adhesive compound, combined with MQ anchoring silicone resin, chelating agents, and silicone-modified HALS additives to construct a multi-stabilized system. This system inhibits post-crosslinking and the migration of siloxane oligomers to the AF coating, mitigating peel strength increases under high-temperature and high-humidity aging. The protective film for AR films prepared from the cured adhesive film of this composition exhibits stable peel strength under all operating conditions and causes no damage to the AR / AF film surface.

Description

Technical Field

[0001] This invention belongs to the field of protective film technology for AR films, specifically relating to an organosilicon pressure-sensitive adhesive composition, an adhesive film, and a protective film for AR films. Background Technology

[0002] With the iterative upgrades of display technology, AR (anti-reflective coating) has become an indispensable core optical component for high-end displays and automotive display devices due to its superior optical control capabilities. The functional surface of AR film is usually composed of an anti-reflective coating (AR coating) and an anti-fingerprint coating (AF coating). This composite structure endows the optical film with low reflectivity, high light transmittance, and excellent hydrophobic and anti-fouling properties, thereby significantly improving display clarity and user experience under extreme lighting conditions.

[0003] Before the AR film is finally bonded to the display substrate, a temporary protective film is applied to its functional surface to resist external physical damage and environmental erosion.

[0004] Currently, the adhesive layer of most protective films used in the industry employs acrylic pressure-sensitive adhesives (Acrylic PSA). Under normal temperature or short-term bonding conditions, this type of acrylic PSA exhibits good wetting properties, moderate initial tack, and relatively stable peel performance, basically meeting the basic requirements for process protection and easy removal.

[0005] However, those skilled in the art have discovered in practice that existing acrylic pressure-sensitive adhesive protective films have significant application defects when applied to AR film surfaces covered with AF coatings. Specifically, some acrylic pressure-sensitive adhesive protective film systems introduce unbonded low-molecular-weight siloxane oligomers. When these are adhered to low surface energy substrates such as AR film AF coatings, free siloxane segments easily migrate and penetrate to the interface, causing AF coating contamination and subsequent process failures. Furthermore, acrylic pressure-sensitive adhesive protective films exhibit peel force increases during high-temperature and high-humidity aging. This abnormal increase in peel force makes the protective film difficult to remove smoothly after the process flow is completed or reliability verification is performed. This often results in difficulty in tearing the film, adhesive residue, or even interlayer delamination between AR functional film layers (such as antireflective layers and anti-reflective layers) due to excessive peel stress, ultimately leading to product scrap.

[0006] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0007] The purpose of this invention is to provide an organosilicon pressure-sensitive adhesive composition, an adhesive film, and a protective film for AR films, which can reduce AF coating contamination while maintaining excellent wettability and moderate initial tack to low surface energy AF coatings, significantly suppress peel force increase during high temperature and high humidity aging, ensure smooth film removal after process flow and reliability verification, and effectively avoid interlayer peeling of AR functional layers and product scrap due to excessive peel stress.

[0008] To achieve the above objectives, a specific embodiment of the present invention provides the following technical solution: an organosilicon pressure-sensitive adhesive composition, comprising, by mass parts, the following raw material components: 85-95 parts of a first MQ base adhesive, 5-15 parts of a second MQ base adhesive, 0.8-1.5 parts of a platinum catalyst, 0.5-1.2 parts of an organosilicon crosslinking agent, 0.3-0.5 parts of an antioxidant, 60-100 parts of an organic solvent, 0.1-0.3 parts of a silane coupling agent, 0.03-0.08 parts of a leveling agent, 0.02-0.05 parts of a defoamer, 0.1-0.2 parts of a chelating agent, 2.0-3.5 parts of MQ anchoring silicone resin, and 0.18-0.3 parts of a silicone-modified HALS additive;

[0009] The first MQ-based adhesive and the second MQ-based adhesive both contain MQ silicone resin components and vinyl-terminated polysiloxane, and the vinyl content of the first MQ-based adhesive is higher than that of the second MQ-based adhesive; the MQ anchoring silicone resin is at least one of low-hydroxyl MQ silicone resin, methyl MQ silicone resin, and vinyl-modified MQ silicone resin.

[0010] In one or more embodiments of the present invention

[0011] The first MQ-based adhesive is a platinum-catalyzed addition-curing silicone pressure-sensitive adhesive containing methyl vinyl MQ silicone resin and vinyl-terminated polydimethylsiloxane;

[0012] The second MQ-based adhesive is a platinum-catalyzed addition-curing silicone pressure-sensitive adhesive containing methyl MQ silicone resin and vinyl-terminated polydimethylsiloxane.

[0013] In one or more embodiments of the present invention, the platinum catalyst is at least one of chloroplatinic acid-olefin complex and platinum-vinylsiloxane complex.

[0014] In one or more embodiments of the present invention, the organosilicon crosslinking agent is at least one of hydrogen-containing silicone oil-type organohydrosiloxane and hydrogen-containing silicone resin-type organohydrosiloxane.

[0015] In one or more embodiments of the present invention, the chelating agent is selected from at least one of zirconium acetylacetonate, aluminum acetylacetonate, and organophosphorus chelating agents.

[0016] In one or more embodiments of the present invention, the silicon-modified HALS additive is at least one of silicon-modified hindered amine light stabilizer, high molecular weight HALS, and composite moisture and heat stabilizer.

[0017] In one or more embodiments of the present invention, the leveling agent is at least one of silicone leveling agents and fluorine-modified leveling agents;

[0018] The defoamer is at least one of polyether defoamer and silicone defoamer;

[0019] The antioxidant is a hindered phenolic antioxidant;

[0020] The silane coupling agent is at least one of aminosilane coupling agents, epoxysilane coupling agents, and ureasilane coupling agents.

[0021] In one or more embodiments of the present invention, the organic solvent is a compound solvent of toluene, ethyl acetate and isopropanol.

[0022] A specific embodiment of the present invention also provides an adhesive film, which is prepared by curing the above-mentioned organosilicon pressure-sensitive adhesive composition.

[0023] A specific embodiment of the present invention also provides a protective film for AR films, comprising:

[0024] Substrate;

[0025] The adhesive film described above is disposed on the surface of the substrate.

[0026] Compared with the prior art, the beneficial effects of the silicone pressure-sensitive adhesive composition, adhesive film, and protective film for AR film of the present invention are as follows:

[0027] (1) The present invention significantly improves the interfacial wetting performance of the pressure-sensitive adhesive composition on the low surface energy AF coating by synergistic compounding of a high vinyl first MQ-based adhesive containing methyl vinyl MQ silicone resin and a low vinyl second MQ-based adhesive containing methyl MQ silicone resin, and by introducing leveling agents and silane coupling agents. At the same time, it imparts appropriate initial adhesion to the adhesive film, ensuring that the protective film can be quickly and smoothly adhered to the AR functional surface in the initial stage of application, and will not affect subsequent positioning or rework operations due to excessive initial adhesion.

[0028] (2) This invention selects MQ anchoring silicone resin, which exhibits excellent compatibility with the dual-base adhesive system composed of a first MQ-based adhesive containing methyl vinyl MQ silicone resin and a second MQ-based adhesive containing methyl MQ silicone resin. The MQ anchoring silicone resin, acting as a physical crosslinking reinforcement point, is uniformly dispersed in the continuous phase of the dual-base adhesive. Its rigid cage-like structure effectively pins the polymer chains, preventing chain slippage. Simultaneously, the MQ anchoring silicone resin and the rigid micro-regions formed by the methyl MQ silicone resin in the second MQ-based adhesive synergistically construct a dual anchoring network of "macroscopic physical crosslinking points + microscopic rigid micro-regions." This mechanism significantly improves the cohesive strength and creep resistance of the adhesive layer while effectively suppressing the increase in peel force caused by intensified molecular chain movement during high-temperature and high-humidity aging, further ensuring the long-term stability of the peel force.

[0029] (3) The MQ anchoring silicone resin used in this invention is interspersed as a rigid node within the polymer network. Through physical locking, it effectively anchors the siloxane oligomers within the cross-linked network, significantly inhibiting the migration and penetration of residual siloxane oligomers into nanoscale defects on the AF coating surface after curing. This mechanism effectively avoids the decrease in oleophobicity of the AF coating caused by oligomer contamination, and this contamination defect cannot be identified by conventional residue-free testing standards. Thus, in addition to conventional quality inspection procedures, it further ensures the functional integrity and long-term stability of the AF coating. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of a protective film for AR film provided in an embodiment of the present invention;

[0032] Figure 2 This is a flowchart illustrating a method for preparing a protective film for AR films according to an embodiment of the present invention. Detailed Implementation

[0033] To enable those skilled in the art to better understand the technical solutions in this disclosure, the technical solutions in the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this disclosure.

[0034] In the process flow and reliability verification of AR film (anti-reflective film), protective film is widely used to cover the AF (anti-fingerprint) coating on its surface to prevent scratches and contamination during subsequent processing and transportation.

[0035] Currently, acrylic pressure-sensitive adhesive protective films are commonly used in existing technologies to achieve the aforementioned protective functions. However, those skilled in the art have discovered through long-term practice that these acrylic pressure-sensitive adhesive protective films have significant application defects when applied to AR film surfaces covered with AF coatings, specifically:

[0036] Firstly, acrylic pressure-sensitive adhesive systems typically contain low-molecular-weight siloxane oligomers that are not involved in cross-linking. When this protective film is bonded to a low surface energy substrate such as an AF coating, these free siloxane segments are highly susceptible to migration and penetration into the AF coating interface under humid, hot, or pressure conditions. This leads to contamination of the AF coating surface, resulting in decreased adhesion or poor appearance in subsequent coating, bonding, or encapsulation processes, ultimately causing functional failure.

[0037] Secondly, acrylic pressure-sensitive adhesive protective films commonly exhibit a significant increase in peel strength during high-temperature and high-humidity aging tests (e.g., 85℃ / 85% RH) or long-term storage. This abnormal increase in peel strength makes the protective film difficult to remove smoothly after the process flow is completed or reliability verification is performed. This often results in difficulty in removing the film, adhesive residue, or even interlayer delamination between AR functional film layers (such as anti-reflective layers) due to excessive peel stress, ultimately leading to product scrap.

[0038] One embodiment of the present invention provides an organosilicon pressure-sensitive adhesive composition, comprising the following raw material components by weight: 85-95 parts of a first MQ base adhesive, 5-15 parts of a second MQ base adhesive, 0.8-1.5 parts of a platinum catalyst, 0.5-1.2 parts of an organosilicon crosslinking agent, 0.3-0.5 parts of an antioxidant, 60-100 parts of an organic solvent, 0.1-0.3 parts of a silane coupling agent, 0.03-0.08 parts of a leveling agent, 0.02-0.05 parts of a defoamer, 0.1-0.2 parts of a chelating agent, 2.0-3.5 parts of MQ anchoring silicone resin, and 0.18-0.3 parts of a silicone-modified HALS additive;

[0039] The first MQ-based adhesive and the second MQ-based adhesive both contain MQ silicone resin components and vinyl-terminated polysiloxane, and the vinyl content of the first MQ-based adhesive is higher than that of the second MQ-based adhesive; the MQ anchoring silicone resin is at least one of low-hydroxyl MQ silicone resin, methyl MQ silicone resin, and vinyl-modified MQ silicone resin.

[0040] In this embodiment, a dual-base adhesive system comprising a first MQ-based adhesive containing methyl vinyl MQ silicone resin and a second MQ-based adhesive containing methyl MQ silicone resin jointly constructs a co-crosslinked organosilicon network that combines rigid microdomains with a flexible continuous phase. This network structure, through its physical topological constraints, can effectively suppress the relaxation and creep of siloxane molecular chain segments under high-temperature conditions, thereby enabling the protective film to possess suitable intrinsic peel strength at room temperature and maintain good peel strength stability in high-temperature environments.

[0041] The dual-base adhesive system, consisting of a first MQ-based adhesive containing methyl vinyl MQ silicone resin and a second MQ-based adhesive containing methyl MQ silicone resin, can undergo a hydrosilylation crosslinking reaction with a hydrogen-containing organosilicon crosslinking agent under the action of a platinum catalyst, forming the main structure of an addition-type organosilicon pressure-sensitive adhesive layer with co-crosslinked organosilicon network characteristics.

[0042] Specifically, the first MQ-based adhesive is a platinum-catalyzed addition-curing silicone pressure-sensitive adhesive containing methyl vinyl MQ silicone resin and vinyl-terminated polydimethylsiloxane; the second MQ-based adhesive is a platinum-catalyzed addition-curing silicone pressure-sensitive adhesive containing methyl MQ silicone resin and vinyl-terminated polydimethylsiloxane.

[0043] In one embodiment, the first MQ base adhesive may be at least one of DOWSIL 7667 Adhesive, DOWSIL 7657 Adhesive, and DOWSIL 7660 Adhesive; the second MQ base adhesive may be at least one of DOWSIL 7647 Adhesive, DOWSIL 7652 Adhesive, and DOWSIL 7646 Adhesive.

[0044] The MQ anchoring silicone resin, acting as rigid nodes, is uniformly dispersed within the aforementioned co-crosslinking network. Its rigid cage-like structure synergistically interacts with the rigid microregions formed by the methyl MQ silicone resin in the second MQ-based adhesive, jointly constructing a dual anchoring network of "macroscopic physical crosslinking points + microscopic rigid microregions." This dual anchoring mechanism significantly enhances the cohesive strength and creep resistance of the adhesive layer while effectively suppressing the increase in peel force caused by intensified molecular chain thermal motion during high-temperature and high-humidity aging, further ensuring the long-term stability of the peel force.

[0045] The MQ anchoring silicone resin is at least one of low-hydroxyl methyl MQ silicone resin, methyl MQ silicone resin, and vinyl-modified MQ silicone resin; for example, the MQ anchoring silicone resin may be selected from at least one of WANICONE® SF6216, DOWSIL's SR 2400Resin, and MSK VMQ-709.

[0046] In addition, the MQ anchoring silicone resin can also effectively anchor the residual siloxane oligomers after curing into the cross-linked network through physical locking, significantly inhibiting their migration and penetration into nanoscale defects on the AF coating surface, thereby avoiding the risk of decreased oleophobicity of the AF coating and ensuring that the product still has excellent functional retention capabilities beyond the conventional residue-free standard test.

[0047] The core function of the chelating agent is to eliminate the risk of post-crosslinking caused by the activity of residual platinum catalyst in the system, ensuring the long-term stability of peel strength from a chemical source. Specifically, during high-temperature and high-humidity aging, unreacted silicon-hydrogen bonds and vinyl groups in the co-crosslinked organosilicon network are prone to undergo slow post-curing crosslinking reactions under the reactivation of residual platinum catalyst. This side reaction is the fundamental chemical cause of the abnormal increase in the peel strength of the protective film. The chelating agent forms a stable chemical complex with the active center of the platinum catalyst, significantly reducing the catalytic activity of residual platinum and blocking post-crosslinking. Thus, it effectively blocks the post-crosslinking pathway at the level of chemical reaction kinetics, eliminating the hidden danger of peel strength continuously increasing with aging time.

[0048] Specifically, the chelating agent can be selected from zirconium acetylacetonate, aluminum acetylacetonate, and organophosphorus chelating agents, preferably zirconium acetylacetonate. Compared with other types, zirconium acetylacetonate has the outstanding advantages of high complexing efficiency, excellent compatibility with organosilicon systems, and no impact on the initial curing activity of platinum catalysis. It can accurately passivate the residual catalyst activity while ensuring the normal crosslinking and curing of the pressure-sensitive adhesive.

[0049] For example, the chelating agent may be selected from at least one of Orgatix ZC-150 and Orgatix ZC-700.

[0050] The role of silicone-modified HALS additives is to construct a long-lasting anti-aging stabilization mechanism to address the deteriorating effects of multiple environmental factors such as humidity, heat, oxygen, and light irradiation on the adhesive layer performance. The silicon functional groups in the additive's molecular structure can form covalent bonds with the organosilicon crosslinking network, achieving permanent anchoring of the additive molecules. This fundamentally alleviates the drawbacks of traditional small-molecule additives, such as easy precipitation and migration under high temperature and humidity conditions. Therefore, this additive can remain stable in the adhesive layer for a long time, continuously exerting its free radical scavenging function, and forming a synergistic stabilizing system with the antioxidants added to the formulation. Together, they block the side crosslinking and molecular chain breakage reactions induced by humidity aging, heat-oxidation degradation, and trace amounts of ultraviolet light, ensuring the performance integrity of the pressure-sensitive adhesive composition under extreme service environments from multiple dimensions.

[0051] Specifically, the silicon-modified HALS additive can be selected from one of silicon-modified hindered amine light stabilizers, high molecular weight HALS, and composite moisture and heat stabilizers, preferably silicon-modified hindered amine light stabilizers. This preferred variety combines reactive anchoring groups with a highly efficient hindered amine stabilizing structure, exhibiting optimal compatibility and anti-aging performance in organosilicon systems. For example, the silicon-modified HALS additive can be selected from at least one of Hostavin® SI420, Eversorb® SI-531, and AdekaARKLS-531.

[0052] In addition, silicon-modified HALS additives can form a synergistic anti-aging system with basic antioxidants, blocking silicon bond breakage and side reactions caused by water vapor and heat oxygen.

[0053] In one or more embodiments of the present invention, the platinum catalyst is used to catalyze a hydrosilylation reaction to achieve efficient crosslinking and curing between the bi-base adhesive system comprising a first MQ-based adhesive containing methyl vinyl MQ silicone resin and a second MQ-based adhesive containing methyl MQ silicone resin and an organosilicon crosslinking agent. The selected platinum catalyst should possess high room temperature latency and moderate heat-initiated activity to ensure the adhesive has sufficient application time and can fully react under the set curing conditions, minimizing the adverse effects of residual active centers after curing on the long-term stability of peel strength.

[0054] Specifically, the platinum catalyst can be selected from at least one of chloroplatinic acid-olefin complexes and platinum-vinylsiloxane complexes. Both types of platinum catalysts have good organosilicon compatibility and controllable catalytic activity, which is beneficial for achieving uniform crosslinking and stable exfoliation force output. For example, the platinum catalyst can be SYL-OFF's 4000 Catalyst (4000 platinum water).

[0055] The organosilicon crosslinking agent is used to undergo a hydrosilylation reaction with the vinyl groups in a bi-base adhesive system consisting of a first MQ-based adhesive containing methyl vinyl MQ silicone resin and a second MQ-based adhesive containing methyl MQ silicone resin, thereby constructing a three-dimensional crosslinked network. The selected crosslinking agent should have a suitable content and distribution of silane groups to ensure that the cured adhesive layer has a moderate crosslinking density—ensuring sufficient cohesive strength and anchoring force without sacrificing initial tack and ease of peeling due to excessive crosslinking.

[0056] Specifically, the organosilicon crosslinking agent can be selected from at least one of organohydrosiloxanes containing hydrosilicone oil and organohydrosilicone resins. Hydrosilicone oil-type crosslinking agents provide more uniform inter-chain crosslinking, while hydrosilicone resin-type crosslinking agents help enhance network rigidity. Both can be used individually or in combination depending on the target performance to flexibly adjust the crosslinking structure and mechanical properties of the adhesive layer. For example, the organosilicon crosslinking agent can be SYL-OFF's 7678 Crosslinker.

[0057] In one specific embodiment, the leveling agent is selected from at least one of silicone leveling agents and fluorine-modified leveling agents; the defoamer is selected from at least one of polyether defoamers and silicone defoamers.

[0058] For example, the silicone leveling agent may be selected from at least one of BYK-306, BYK-333, and TEGO® Glide 410; the fluorine-modified leveling agent may be selected from at least one of BYK-377, EFKA® FL 3777, and TEGO® Glide 270. The polyether defoamer may be selected from at least one of BYK-024, EFKA® FA 4670, and Agtan 315; the silicone defoamer may be selected from at least one of BYK-A 530, TEGO® Airex 900, and EFKA® FA 6600.

[0059] The selected leveling agent and defoamer both exhibit excellent compatibility with the silicone pressure-sensitive adhesive system. The leveling agent, by reducing the surface tension of the adhesive, improves the dynamic wetting and spreading behavior of the adhesive on the substrate, effectively eliminating pinholes and orange peel defects caused by differences in surface tension gradients during coating. The defoamer, by reducing the gas-liquid interfacial tension and disrupting the stable bubble film structure, promotes the rapid rupture and expulsion of bubbles entrained during adhesive preparation and high-speed coating, preventing the formation of pinholes and bubble depressions.

[0060] The synergistic effect of these two agents ensures the smoothness and density of the coated adhesive layer, resulting in an adhesive layer with excellent optical transmittance and surface uniformity after curing. This meets the stringent requirements of AR film protective films for high transparency and low optical interference, while preventing localized adhesion failure or poor appearance caused by microscopic defects. The antioxidant effectively delays the oxidative breakage and side-crosslinking reactions of the silicone molecular chains by capturing active free radicals generated by oxidation reactions in the adhesive layer under thermo-oxidative conditions, thereby inhibiting performance degradation of the adhesive layer during high-temperature aging. Simultaneously, the hindered phenolic antioxidant and the silicone-modified HALS additive form a synergistic stabilizing system. The antioxidant focuses on the rapid capture of free radicals in the early stages of thermo-oxidative processes, while HALS provides long-term and continuous stabilization. The two complement each other synergistically, jointly improving the long-term aging resistance and peel strength stability of the pressure-sensitive adhesive composition under extreme high-temperature and high-humidity environments from different stages of action.

[0061] Specifically, the antioxidant is a hindered phenolic antioxidant. For example, the antioxidant may be selected from at least one of IRGANOX 1010, IRGANOX 1076, and IRGANOX 1330.

[0062] The silane coupling agent is used to enhance the interfacial adhesion between the adhesive layer and the PET optical base film, while simultaneously improving the optical purity of the film. Specifically, the siloxane groups in the silane coupling agent molecule can form chemical bonds with the hydroxyl groups on the surface of the PET base film, while the functional groups at the other end participate in the cross-linking network of the silicone pressure-sensitive adhesive, thereby constructing a strong chemical bridge between the adhesive layer and the base film interface. This effectively prevents adhesive layer detachment and delamination failure, further stabilizing the overall mechanical properties of the adhesive layer. Furthermore, the introduction of the silane coupling agent helps suppress interfacial light scattering, improving the optical transmittance and clarity of the protective film.

[0063] Specifically, the silane coupling agent is at least one of aminosilane coupling agents, epoxysilane coupling agents, and ureosilane coupling agents.

[0064] In one embodiment, the silane coupling agent is at least one of KH-550, KH-560, and silane coupling agent 6020, preferably KH-560 epoxy silane coupling agent. The epoxy functional groups contained in KH-560 have excellent reactivity and compatibility with the organosilicon system, which can enhance the interfacial adhesion while maintaining the optical purity of the adhesive layer to the greatest extent, thus meeting the dual requirements of bonding reliability and optical quality.

[0065] The organic solvent is a compound solvent composed of toluene, ethyl acetate, and isopropanol. All of these solvents possess good solubility for silicone resins and suitable volatility, enabling them to fully dissolve or disperse the solid components into a uniform coating liquid system. This ensures effective mixing and stable dispersion of the components, while also providing a suitable solid content and viscosity window for subsequent coating processes, facilitating precise control of the adhesive layer thickness.

[0066] Preferably, the volume ratio of toluene, ethyl acetate, and isopropanol is 2:5:3. The compounded solvent precisely controls the viscosity and evaporation rate of the adhesive, and the coating aids ensure an extremely smooth adhesive layer, avoiding viscosity fluctuations caused by appearance defects and uneven local stress.

[0067] A specific embodiment of the present invention also provides an adhesive film, which is prepared by curing the above-mentioned organosilicon pressure-sensitive adhesive composition.

[0068] like Figure 1 As shown, a specific embodiment of the present invention also provides a protective film for AR films, comprising: a substrate A; and an adhesive film B, as described above, disposed on the surface of the substrate A. The protective film for AR films is adhered to the functional surface of the AR film.

[0069] Specifically, the preparation method of the protective film for AR film can be as follows: Figure 2 As shown, it includes the following steps:

[0070] S1. Weigh 85-95 parts of the first MQ base adhesive, 5-15 parts of the second MQ base adhesive, 0.8-1.5 parts of platinum catalyst, 0.5-1.2 parts of organosilicon crosslinking agent, 0.3-0.5 parts of antioxidant, 60-100 parts of organic solvent, 0.1-0.3 parts of silane coupling agent, 0.03-0.08 parts of leveling agent, 0.02-0.05 parts of defoamer, 0.1-0.2 parts of chelating agent, 2.0-3.5 parts of MQ anchoring silicone resin, and 0.18-0.3 parts of silicone-modified HALS additive. Stir and mix well, and let stand to defoam, to obtain an organosilicon pressure-sensitive adhesive composition. The organic solvent is a compound solvent of toluene, ethyl acetate, and isopropanol in a volume ratio of 2:5:3.

[0071] S2. The silicone pressure-sensitive adhesive composition is coated onto one side of the substrate using a slot coating process, dried and crosslinked in sections at 120°C, and then laminated with a release film to obtain a protective film for AR film.

[0072] The organosilicon pressure-sensitive adhesive composition, adhesive film, and protective film for AR film of the present invention will be described in detail below with reference to specific embodiments and comparative examples.

[0073] Example 1

[0074] like Figure 1 As shown, a protective film for AR film includes the following film layer structure:

[0075] Fluorine release film, 75 μm thick.

[0076] Optical PET base film (substrate), 75μm thick.

[0077] The silicone pressure-sensitive adhesive layer has a thickness of 15 μm; by weight, the corresponding silicone pressure-sensitive adhesive composition consists of the following components:

[0078] 90 parts of the first MQ base adhesive (DOWSIL's 7667 Adhesive);

[0079] 10 parts of the second MQ base adhesive (DOWSIL's 7647 Adhesive);

[0080] 0.8 parts of platinum catalyst (SYL-OFF 4000 Catalyst);

[0081] 0.8 parts of silicone crosslinking agent (SYL-OFF 7678 Crosslinker);

[0082] Antioxidant (IRGANOX 1010) 0.3 parts;

[0083] 80 parts of organic solvent (a compound solvent formed by toluene, ethyl acetate and isopropanol in a volume ratio of 2:5:3);

[0084] 0.2 parts of silane coupling agent (KH-560);

[0085] 0.05 parts of silicone leveling agent (BYK-306);

[0086] Polyether defoamer (BYK-024) 0.03 parts;

[0087] 0.15 parts of acetylacetone zirconium chelating agent (Orgatix ZC-150);

[0088] 3.0 parts of MQ anchoring silicone resin (WANICONE® SF6216);

[0089] 0.2 parts of silicon-modified HALS additive (Hostavin® SI420).

[0090] Example 2

[0091] like Figure 1 As shown, a protective film for AR film includes the following film layer structure:

[0092] Fluorine release film, 75 μm thick.

[0093] Optical PET base film (substrate), 75μm thick.

[0094] The silicone pressure-sensitive adhesive layer has a thickness of 15 μm; by weight, the corresponding silicone pressure-sensitive adhesive composition consists of the following components:

[0095] 85 parts of the first MQ base adhesive (DOWSIL's 7667 Adhesive);

[0096] 15 parts of the second MQ base adhesive (DOWSIL 7647 Adhesive);

[0097] 1.0 part of platinum catalyst (SYL-OFF 4000 Catalyst);

[0098] 0.5 parts of silicone crosslinking agent (SYL-OFF 7678 Crosslinker);

[0099] Antioxidant (IRGANOX 1010) 0.5 parts;

[0100] 100 parts of organic solvent (a compound solvent formed by toluene, ethyl acetate and isopropanol in a volume ratio of 2:5:3);

[0101] 0.3 parts of silane coupling agent (KH-560);

[0102] 0.08 parts of silicone leveling agent (BYK-306);

[0103] Polyether defoamer (BYK-024) 0.05 parts;

[0104] 0.2 parts of acetylacetone zirconium chelating agent (Orgatix ZC-150);

[0105] 3.5 parts of MQ anchoring silicone resin (WANICONE® SF6216);

[0106] Silicon-modified HALS additive (Hostavin® SI420) 0.3 parts.

[0107] Example 3

[0108] like Figure 1 As shown, a protective film for AR film includes the following film layer structure:

[0109] Fluorine release film, 75 μm thick.

[0110] Optical PET base film (substrate), 75μm thick.

[0111] The silicone pressure-sensitive adhesive layer has a thickness of 15 μm; by weight, the corresponding silicone pressure-sensitive adhesive composition consists of the following components:

[0112] 95 parts of the first MQ base adhesive (DOWSIL's 7667 Adhesive);

[0113] 5 parts of the second MQ base adhesive (DOWSIL 7647 Adhesive);

[0114] 1.5 parts of platinum catalyst (SYL-OFF 4000 Catalyst);

[0115] 1.2 parts of silicone crosslinking agent (SYL-OFF 7678 Crosslinker);

[0116] Antioxidant (IRGANOX 1010) 0.4 parts;

[0117] 60 parts of organic solvent (a compound solvent formed by toluene, ethyl acetate and isopropanol in a volume ratio of 2:5:3);

[0118] 0.1 parts of silane coupling agent (KH-560);

[0119] 0.03 parts of silicone leveling agent (BYK-306);

[0120] Polyether defoamer (BYK-024) 0.02 parts;

[0121] 0.1 parts of acetylacetone zirconium chelating agent (Orgatix ZC-150);

[0122] 2.0 parts of MQ anchoring silicone resin (WANICONE® SF6216);

[0123] 0.18 parts of silicon-modified HALS additive (Hostavin® SI420).

[0124] Comparative Example 1

[0125] A protective film for AR film includes the following film layer structure:

[0126] Fluorine release film, 75 μm thick.

[0127] The commercially available UV-curable acrylic pressure-sensitive adhesive Lintec G-7808 was applied and cured according to the supplier's recommended process to form an adhesive layer with a thickness of 15μm.

[0128] Optical PET base film (substrate), 75μm thick.

[0129] Comparative Example 2

[0130] A protective film for AR film includes the following film layer structure:

[0131] Fluorine release film, 75 μm thick.

[0132] Optical PET base film (substrate), 75μm thick.

[0133] The silicone pressure-sensitive adhesive layer has a thickness of 15 μm; by weight, the corresponding silicone pressure-sensitive adhesive composition consists of the following components:

[0134] 85 parts of the first MQ base adhesive (DOWSIL's 7667 Adhesive);

[0135] 15 parts of the second MQ base adhesive (DOWSIL 7647 Adhesive);

[0136] 1.0 part of platinum catalyst (SYL-OFF 4000 Catalyst);

[0137] 0.5 parts of silicone crosslinking agent (SYL-OFF 7678 Crosslinker);

[0138] Antioxidant (IRGANOX 1010) 0.5 parts;

[0139] 100 parts of organic solvent (a compound solvent formed by toluene, ethyl acetate and isopropanol in a volume ratio of 2:5:3);

[0140] 0.3 parts of silane coupling agent (KH-560);

[0141] 0.08 parts of silicone leveling agent (BYK-306);

[0142] 0.05 parts of polyether defoamer (BYK-024).

[0143] Comparative Example 3

[0144] A protective film for AR film includes the following film layer structure:

[0145] Fluorine release film, 75 μm thick.

[0146] Optical PET base film (substrate), 75μm thick.

[0147] The silicone pressure-sensitive adhesive layer has a thickness of 15 μm; by weight, the corresponding silicone pressure-sensitive adhesive composition consists of the following components:

[0148] 100 parts of the first MQ base adhesive (DOWSIL's 7667 Adhesive);

[0149] 1.0 part of platinum catalyst (SYL-OFF 4000 Catalyst);

[0150] 0.5 parts of silicone crosslinking agent (SYL-OFF 7678 Crosslinker);

[0151] Antioxidant (IRGANOX 1010) 0.5 parts;

[0152] 100 parts of organic solvent (a compound solvent formed by toluene, ethyl acetate and isopropanol in a volume ratio of 2:5:3);

[0153] 0.3 parts of silane coupling agent (KH-560);

[0154] 0.08 parts of silicone leveling agent (BYK-306);

[0155] Polyether defoamer (BYK-024) 0.05 parts;

[0156] 0.2 parts of acetylacetone zirconium chelating agent (Orgatix ZC-150);

[0157] 3.5 parts of MQ anchoring silicone resin (WANICONE® SF6216);

[0158] 0.3 parts of silicon-modified HALS additive (Hostavin® SI420).

[0159] It should be noted that the structures of Examples 1-3 and Comparative Examples 1-3 are basically the same, the only difference being the formulation of the silicone pressure-sensitive adhesive composition.

[0160] Furthermore, the unified preparation process for the protective film of AR film in Examples 1-3 and Comparative Examples 1-3 (except for the preparation process of the organosilicon pressure-sensitive adhesive composition in Comparative Example 1) is as follows:

[0161] Add the compound solvent and silicone resin in sequence according to the formula, stir at low speed to dissolve, then add the catalyst, crosslinking agent and various functional additives in sequence, stir at high speed for 30 minutes until the system is mixed, let stand at room temperature for 40 minutes to defoam and obtain each composition. Use the same slit coating process to coat each composition on the surface of a 75μm optical PET base film, dry and crosslink in sections at 120℃, and then laminate with a 75μm fluorine release film. After curing at room temperature for 24 hours, the finished product is obtained, and performance testing is carried out in a unified environment.

[0162] The performance tests of the protective films for AR films in Examples 1-3 and Comparative Examples 1-3 were conducted as follows. After removing the release film, the protective films for the functional surfaces of AR films prepared in each of the above examples and comparative examples were bonded to the functional surfaces of a commercially available AR film (model AR100-T082V-AD-HD) using the same bonding process. The peel strength was tested after storage under the same conditions: room temperature (25℃ / 72h), high temperature aging (60℃ / 72h), and damp heat aging (85℃ / 85%RH). Three parallel samples were tested under each condition, and the arithmetic mean was taken as the test result to obtain the test results for each example and comparative example.

[0163] Wherein, the maximum fluctuation ratio of peel force = (maximum peel force under each condition - minimum peel force) ÷ minimum peel force × 100%, and the maximum fluctuation ratio of the target peel force of this invention is ≤ 3%.

[0164] 1. Residual adhesive and adhesive transfer: Referring to GB / T 2792 standard, after peeling off the film, observe the surface of the AR film and the adhesive surface of the protective film visually and with a 10x magnifying glass.

[0165] 2. Coating damage: After peeling off the film, immediately test the water droplet angle of the AR film AF coating. The attenuation should be ≤5° compared with before bonding. Use an optical microscope (200x) to observe whether there are scratches or peeling on the coating surface.

[0166] 3. Film appearance: Observe whether the protective film has any peeling, bubbling, delamination or other phenomena.

[0167] 4. Optical performance: Use a haze meter and a transmittance meter to test the changes in haze and transmittance (T%) of the AR film before and after the protective film is applied. The difference should be ≤0.5% and ≤1%, respectively.

[0168]

[0169] Among them, the pressure-sensitive adhesive composition of Comparative Example 1 is a traditional acrylic adhesive system (non-silicone system); the silicone pressure-sensitive adhesive composition of Comparative Example 2 is a control system without chelating agent, MQ anchoring silicone resin and silicone modified HALS additive; the silicone pressure-sensitive adhesive composition of Comparative Example 3 is a single-base adhesive control system without second MQ base adhesive.

[0170] As shown in the table above, this invention precisely blends a high-vinyl first MQ-based adhesive containing methyl vinyl MQ silicone resin with a low-vinyl second MQ-based adhesive containing methyl MQ silicone resin. Combined with a core stabilizing agent consisting of a chelating agent, MQ anchoring silicone resin, and silicone-modified HALS additives, and supplemented with a complete set of optical-grade coating, coupling, and antioxidant additives, a multi-dimensional synergistic and stable organosilicon pressure-sensitive adhesive system is constructed. This system can solve the problem of drastic viscosity increase under long-term storage and high-temperature, high-humidity aging conditions with traditional acrylic pressure-sensitive adhesives as the adhesive layer, as well as the problems of poor weather resistance and insufficient stability of single organosilicon silicone.

[0171] Experiments show that relying solely on the dual-resin skeleton (Comparative Example 2) or solely on the complete set of tack stabilizers (Comparative Example 3) cannot achieve the peel force stability of the present invention, with a maximum fluctuation ratio of ≤3%. Only when the two are combined (Examples 1-3) does a synergistic stabilizing effect far exceeding the expectations in the art occur. This demonstrates that the interaction between the dual-base adhesive system and the multi-dimensional tack stabilizers of the present invention is not a simple addition, but rather constitutes an interdependent and indispensable organic whole. Furthermore, Comparative Example 3, using a single high-vinyl first MQ-based adhesive containing methyl vinyl MQ silicone resin, even with the addition of all tack stabilizers, exhibited a significantly higher room-temperature peel force (8.86 gf / 25 mm) than Example 2 (1.41 gf / 25 mm). This indicates that the addition of a low-vinyl second MQ-based adhesive containing methyl MQ silicone resin is crucial for adjusting the adhesive layer modulus and obtaining a suitable low initial peel force. Meanwhile, the peel strength fluctuation ratio after high temperature and high humidity (46.5%) is still much higher than that of the embodiments of the present invention (≤3%), indicating that additives alone cannot compensate for the inherent deficiency of the heat resistance of the basic network structure. The lack of rigid microregions formed by the methyl MQ silicone resin in the second MQ-based adhesive makes the adhesive network more prone to chain segment rearrangement and creep under thermal stress, leading to increased viscosity. This further demonstrates that a specific ratio of the first MQ-based adhesive containing methyl vinyl MQ silicone resin and the second MQ-based adhesive containing methyl MQ silicone resin is a necessary means to construct a stable network framework, while the multifunctional additive further improves the structure of this network framework. The two work synergistically and are indispensable.

[0172] The three embodiments provided by this invention all achieve a peel force fluctuation of ≤3% under all working conditions, which is far superior to the industry standard of ≤10% peel force fluctuation. Furthermore, the adhesion remains nearly constant under high temperature and humid conditions, while also possessing advantages such as excellent coating appearance, no residue, no exudation, and no damage to the AR / AF optical coating. Among them, the optimal formulation in Embodiment 2 balances ultra-low peel force, minimal performance fluctuation, excellent optical appearance, and long-term weather resistance, making it the most suitable for mass production.

[0173] Three sets of comparative examples fully verify the innovation and necessity of this solution: the traditional acrylic pressure-sensitive adhesive system has a fatal tack creep defect; the dual-resin additive-free system and the single-resin additive-full system cannot achieve stable peel force, proving that the dual-base adhesive system + multiple types of tack stabilizers are the core key to achieving ultra-stable protection, and none of them can be omitted. It can fully meet the requirements of high-end AR-AF composite film for precision protection, long-term storage, and reliability testing under harsh working conditions.

[0174] In summary, the beneficial effects of the present invention are as follows:

[0175] 1. Innovative dual-level formulation system: Constructing a dual-base adhesive compound system + multi-dimensional tack stabilizer system. The first MQ base adhesive containing methyl vinyl MQ silicone resin and the second MQ base adhesive containing methyl MQ silicone resin are compounded to build a weather-resistant basic network. Combined with three types of special additives for anchoring, chelation and aging resistance, the system addresses the problems of post-crosslinking and tack ramp-up of adhesives from three dimensions: molecular chain binding, side reaction blocking, and protection against humid heat degradation.

[0176] 2. Super stable performance innovation: Through precise compounding of additives and synergistic effect, the peel force fluctuation ratio of the protective film under all working conditions is reduced from the industry standard of 10% to ≤3%, achieving a nearly constant peel force across all temperature, high temperature, and humid heat aging ranges. This can solve the problems of film tearing jamming and AR main film detachment and scrapping, and significantly improve the product yield.

[0177] 3. Optical and Mass Production Adaptation Innovation: Selects high-quality optical-grade special additives that are free from precipitation, migration, and adhesive transfer, and do not corrode or damage the AR nano antireflective layer and AF anti-fingerprint coating, ensuring the optical purity of the film material throughout the process; the formulation components are simple, industrial raw materials are readily available, and it is compatible with existing coating mass production equipment, requiring no production line modification. The process is mature, the cost is controllable, and the yield is excellent.

[0178] 4. Coating quality upgrade and innovation: The compound special solvent system is combined with suitable leveling, defoaming and coupling agents to precisely control the film-forming performance of the adhesive, completely eliminating appearance defects such as pinholes, bubbles and particles in conventional silicone coatings. At the same time, it improves the adhesion between the adhesive layer and the base film, alleviates delamination and edge lifting problems, and is suitable for the ultra-high appearance requirements of high-end optical films.

[0179] It will be apparent to those skilled in the art that this disclosure is not limited to the details of the exemplary embodiments described above, and that this disclosure can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of this disclosure is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within this disclosure. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0180] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A silicone pressure-sensitive adhesive composition, characterized in that, By weight, it comprises the following raw material components: 85-95 parts of first MQ base adhesive, 5-15 parts of second MQ base adhesive, 0.8-1.5 parts of platinum catalyst, 0.5-1.2 parts of organosilicon crosslinking agent, 0.3-0.5 parts of antioxidant, 60-100 parts of organic solvent, 0.1-0.3 parts of silane coupling agent, 0.03-0.08 parts of leveling agent, 0.02-0.05 parts of defoamer, 0.1-0.2 parts of chelating agent, 2.0-3.5 parts of MQ anchoring silicone resin, and 0.18-0.3 parts of silicone-modified HALS additive; The first MQ-based adhesive and the second MQ-based adhesive both contain MQ silicone resin components and vinyl-terminated polysiloxane, and the vinyl content of the first MQ-based adhesive is higher than that of the second MQ-based adhesive; the MQ anchoring silicone resin is at least one of low-hydroxyl MQ silicone resin, methyl MQ silicone resin, and vinyl-modified MQ silicone resin.

2. The organosilicon pressure-sensitive adhesive composition according to claim 1, characterized in that, The first MQ-based adhesive is a platinum-catalyzed addition-curing silicone pressure-sensitive adhesive containing methyl vinyl MQ silicone resin and vinyl-terminated polydimethylsiloxane; The second MQ-based adhesive is a platinum-catalyzed addition-curing silicone pressure-sensitive adhesive containing methyl MQ silicone resin and vinyl-terminated polydimethylsiloxane.

3. The organosilicon pressure-sensitive adhesive composition according to claim 1, characterized in that, The platinum catalyst is at least one of chloroplatinic acid-olefin complex and platinum-vinylsiloxane complex.

4. The organosilicon pressure-sensitive adhesive composition according to claim 1, characterized in that, The organosilicon crosslinking agent is at least one of hydrogen-containing silicone oil-type organohydrosiloxane and hydrogen-containing silicone resin-type organohydrosiloxane.

5. The organosilicon pressure-sensitive adhesive composition according to claim 1, characterized in that, The chelating agent is selected from at least one of zirconium acetylacetonate, aluminum acetylacetonate, and organophosphorus chelating agents.

6. The organosilicon pressure-sensitive adhesive composition according to claim 1, characterized in that, The silicon-modified HALS additive is at least one of silicon-modified hindered amine light stabilizer, high molecular weight HALS, and composite moisture and heat stabilizer.

7. The organosilicon pressure-sensitive adhesive composition according to claim 1, characterized in that, The leveling agent is at least one of silicone-based leveling agents and fluorine-modified leveling agents; The defoamer is at least one of polyether defoamer and silicone defoamer; The antioxidant is a hindered phenolic antioxidant; The silane coupling agent is at least one of aminosilane coupling agents, epoxysilane coupling agents, and ureasilane coupling agents.

8. The organosilicon pressure-sensitive adhesive composition according to claim 1, characterized in that, The organic solvent is a compound solvent of toluene, ethyl acetate and isopropanol.

9. A film, characterized in that, It is prepared by curing the organosilicon pressure-sensitive adhesive composition according to any one of claims 1 to 8.

10. A protective film for AR films, characterized in that, include: Substrate; The adhesive film as described in claim 9 is disposed on the surface of the substrate.

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