Anti-glare PMMA type polaroid

Abstract

The invention discloses an anti-glare PMMA (Polymethyl Methacrylate) type polaroid in the technical field of polaroids. The anti-glare PMMA type polaroid comprises a PMMA optical film base material, an anti-glare coating is arranged on the surface of the base material; the anti-dazzle optical film is arranged to serve as a protective layer of the PVA upper protective film, and silicon particles are applied to the anti-dazzle composition, so that the anti-dazzle composition has a large surface area and is uniformly dispersed in coating liquid to achieve a diffuse reflection effect, and the haze can reach 25% or above; meanwhile, a novel polaroid PVA layer and PMMA layer adhesive is developed, specifically, a UV adhesive is adopted to replace a water glue thermocuring adhesive, the drying speed of a polaroid is reduced by adjusting process parameters, the difference caused by size change due to heat among all components of the polaroid is reduced, and therefore the risk of peeling layering caused by low adhesive force is reduced.

Description

Technical Field

[0001] The invention relates to an anti-glare PMMA type polarizer, belonging to the technical field of polarizers. Background Art

[0002] Polarizers are used more and more widely, playing an important role in homes, offices, and outdoor advertising. With the development of product needs, the development of high contrast, wide viewing angle, thinness, large size, high precision and diversified additional functions can meet human needs.

[0003] Generally, monitors are used in environments with external light sources, which will produce glare due to the reflection effect. In order to enhance the visual viewing effect, an anti-glare film is used on the outermost layer of the monitor to reduce the side effects of mirror-reflected light on the human eye when viewing the monitor and reduce the reflected light caused by external stray light.

[0004] Large-size LCDs are mostly used for outdoor commercial displays. In hot and humid environments, polarizers must not be affected by moisture, which would reduce their polarization ability and affect the durability of the polarizer, as well as cause problems such as light leakage, yellowing, and color unevenness. Therefore, ultra-large-size polarizers have extremely stringent requirements for weather resistance and water resistance. Traditional coating processes have problems such as uneven coating, easy to fall off, and poor optical performance, and cannot achieve this technical goal well. Summary of the invention

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art, namely, the poor anti-glare performance, poor coating adhesion and insufficient wear resistance in the preparation of the existing polarizer.

[0006] In order to solve the above technical problems, the present invention is implemented by adopting the following technical solutions: Provided is an anti-glare PMMA polarizer, comprising: a PMMA optical film substrate; an anti-glare coating is provided on the surface of the substrate; The anti-glare coating comprises acrylate prepolymer, acrylate monomer, photoinitiator, surfactant and silicon particles; The acrylate prepolymer and acrylate monomer are added to a solvent and mixed, then a photoinitiator and a surfactant are added to form a first mixed solution, and finally silicon particles are added to form a coating composition; The coating composition is provided with a pretreatment process before surface coating, and a multi-stage drying process is provided after coating, followed by a UV curing process; a protective film is applied after the UV curing process, and a pressure-sensitive adhesive is provided on the outer side of the protective film; Wherein, the PMMA is provided with two layers and is respectively attached to both sides of the PVA film.

[0007] Furthermore, the solvent includes ketones, esters and benzenes.

[0008] Furthermore, the photoinitiator is a free radical photoinitiator, and the photoinitiator polymerizes with the acrylate monomer under UV irradiation.

[0009] Further, the pretreatment process includes oven preheating and plasma cleaning of PMMA; Wherein, the plasma cleaning is performed on two layers of PMMA films before UV curing.

[0010] Further, the UV curing process includes: The PVA layer and the PMMA layer are bonded together by a UV curing adhesive, and the UV curing adhesive is cured under ultraviolet irradiation to form an adhesive layer.

[0011] Furthermore, the UV curing process includes at least 3 curing devices.

[0012] Furthermore, the protective film is attached to the surface of the coating and a pressure-sensitive adhesive is provided on the outer side of the protective film.

[0013] Furthermore, the adhesive force of the pressure-sensitive adhesive is within 300 gf / 25 mm.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention sets an anti-glare optical film as a protective layer of the protective film on PVA, and silicon particles are used in the anti-glare composition, which has a large surface area and is evenly dispersed in the coating liquid to play a diffuse reflection role, and the haze can reach more than 25%; at the same time, a new polarizer PVA layer and PMMA layer adhesive is developed: UV adhesive is used instead of water-based thermal curing adhesive to adjust the process parameters, moderate the drying speed of polarizers, reduce the heat between the various components of the polarizer and cause dimensional changes, thereby reducing the risk of peeling delamination due to low adhesion. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Shown is a diagram of the configuration process of the anti-glare coating of the present invention; Figure 2 Shown is a flow chart of the surface coating production of the present invention; Figure 3 Shown is the PMMA bonding diagram of the present invention. DETAILED DESCRIPTION

[0016] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0017] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances. Embodiment 1:

[0018] Provided is an anti-glare PMMA polarizer, comprising: a PMMA optical film substrate; an anti-glare coating is provided on the surface of the substrate; The anti-glare coating comprises acrylate prepolymer, acrylate monomer, photoinitiator, surfactant and silicon particles; The acrylate prepolymer and acrylate monomer are added to a solvent and mixed, then a photoinitiator and a surfactant are added to form a first mixed solution, and finally silicon particles are added to form a coating composition; The coating composition is provided with a pretreatment process before surface coating, and a multi-stage drying process is provided after coating, followed by a UV curing process.

[0019] The main components of the anti-glare coating include acrylate prepolymer, acrylate monomer, photoinitiator, surfactant and silicon particles. Acrylate prepolymer and acrylate monomer are the basic materials of the coating, which can undergo polymerization reaction under ultraviolet irradiation to form a hard coating structure.

[0020] Photoinitiators are used to start the polymerization reaction under ultraviolet light, so that the coating can be cured in a short time; surfactants reduce the surface tension of the coating liquid, improve the fluidity and wettability of the coating liquid, and ensure that the coating is evenly covered on the surface of the substrate; silicon particles are used as additives to enhance the anti-glare effect of the coating, providing a certain haze, so that the coating has a stronger ability to scatter light, further improving the anti-glare effect.

[0021] like Figure 1 As shown, the preparation of the coating composition first adds acrylate prepolymer and acrylate monomer into a solvent for mixing. The solvent types include ketones, esters and benzenes, which can effectively reduce the viscosity of the coating solution so that the coating can be evenly coated on the surface of the PMMA substrate; after mixing, a photoinitiator and a surfactant are added to the solution, which helps to start the polymerization reaction during the UV curing process and improve the fluidity and adhesion of the coating. Finally, silicon particles are added, which help improve the haze and anti-glare effects of the coating and enhance the wear resistance and scratch resistance of the coating.

[0022] like Figure 2As shown, before coating, the PMMA optical film is pre-treated. In this actual production, Corona treatment is selected, which uses high voltage to generate an electric field between two electrodes to form high-energy electrons and oxygen molecules near the surface of the substrate, thereby activating the surface of the substrate; in this process, the film surface will be exposed to high-energy ions, free radicals, ozone and other gases, which will react with the molecules on the film surface, break the molecular chains, and produce an active surface containing polar groups. This ensures the uniformity and good adhesion of the coating.

[0023] At the same time, the PVA film is preheated, and then the PMMA treated with Corona is bonded to both sides of the PVA film. The surface of the PMMA film has been coated with UV light-curing adhesive, and then the PMMA film and the PVA film are bonded, and then cured by UV light, and finally AG particles are coated. Similarly, UV light curing is required after coating; the coating undergoes multiple drying processes to remove excess solvent to ensure the stability and uniformity of the coating during further processing.

[0024] During the UV curing process, the UV curing adhesive is cured under ultraviolet light to form an adhesive layer. The coating is cured by the energy of ultraviolet light to ensure the hardness and durability of the coating; and the UV curing process includes at least three curing devices.

[0025] Since UV adhesive is used to replace water-based heat-curing adhesive, the photoinitiator in the UV curing material absorbs ultraviolet light to generate active free radicals or cations, which trigger monomer polymerization and cross-linking chemical reactions, and the adhesive is converted from liquid to solid within seconds; the photoinitiator (PI) changes from a ground state to an excited state under UV irradiation, and then decomposes into free radicals, which combine with monomers and chain grow on this basis to polymerize carbon-carbon double bonds, accompanied by the transfer and termination of free radicals on the growing chain, shortening the time from 3 minutes for water-based heat-curing adhesives to a few seconds, which can greatly simplify the original equipment such as ovens.

[0026] The protective film is attached to the surface of the coating and a pressure-sensitive adhesive is arranged on the outside of the protective film; the protective film not only protects the coating from damage, but also keeps the coating clean during the production, transportation and use of the polarizer. The pressure-sensitive adhesive is arranged on the outside of the protective film, which can provide sufficient adhesion to ensure that the film layer is firmly adhered to the surface without additional heating or pressure.

[0027] The pressure-sensitive adhesive has an adhesion of less than 300 gf / 25 mm, which can ensure that the protective film can be firmly adhered, and at the same time facilitate the removal or replacement of the film at a later stage. The lower adhesion can prevent the film from damaging the coating or substrate when it is removed, ensuring that the film layer can be easily and non-destructively removed, providing greater processing flexibility.

[0028] like Figure 3 As shown, because the pressure-sensitive adhesive (PSA) has high adhesion, it is easy to cause difficulty in reworking when the panel is reworked, and even the possibility of polarizer breakage may occur. Increasing the gel fraction of the PSA glue reduces its adhesion performance. At the same time, after the thickness of the PSA glue is thinned, the storage modulus of the pressure-sensitive adhesive layer tends to increase when external stress is applied to the pressure-sensitive adhesive layer at a high speed, which can effectively inhibit the generation of nano-slits. The higher the storage modulus, the harder the PSA glue, the lower the mobility of its chain segments, and the weaker the bonding hysteresis; during the peeling process, the energy is dissipated through the movement of the molecular chain, showing a lower peeling force, which has an improvement effect on the difficulty of rework tearing.

[0029] The traditional method for preparing anti-glare polarizers is usually to first apply an anti-glare coating on a PMMA substrate, then perform UV curing to obtain an anti-glare PMMA optical film (AG-PMMA), then laminate the AG-PMMA (upper T), PMMA compensation film (lower T) and PVA, and finally cure again. In this traditional process, the manufacture of the AG-PMMA film generally needs to be completed on another production line, and then rolled back to the polarizer production line to laminate PVA together with the PMMA compensation film: Compared with the traditional method, this embodiment first laminates the general-purpose PMMA and PMMA compensation film with PVA and then directly applies an anti-glare coating on the general-purpose PMMA surface, completing the process of anti-glare polarizers in one step. The process cycle of the anti-glare polarizer is greatly shortened, and the process efficiency of the polarizer is improved. In addition, in this embodiment, the surface of the PMMA film is subjected to Corona treatment before coating, so as to enhance the adhesion between the PMMA film and the PVA film, and ensure that the surface of the substrate can be effectively and firmly bonded with the PVA film before the anti-glare coating is applied. By performing Corona treatment between the PMMA film and the PVA film, the adhesion between the two films is improved, the risk of coating peeling is reduced, and the long-term stability of the product is ensured. At the same time, through the UV curing process, not only the hardness and anti-glare effect of the coating are guaranteed, but also the interlayer adhesion is effectively enhanced, so that the final product has higher wear resistance and stability during use. Embodiment 2:

[0030] like Figure 2 As shown, all components need to be mixed evenly before adding. The solvent, acrylate prepolymer and acrylate monomer should be mixed in a stirrer to ensure sufficient dissolution and prevent polymer precipitation.

[0031] When preparing the coating solution, first add the ketone, ester or benzene solvent into the reaction vessel and stir slowly to reduce the viscosity of the solvent so that it can achieve the ideal coating properties. Add the photoinitiator and surfactant into the solvent mixture to ensure that the photoinitiator is completely dissolved and the surfactant can be evenly distributed in the coating solution to ensure uniformity and good adhesion of the coating.

[0032] Finally, add the pre-prepared silicon particles for efficient dispersion to ensure uniform distribution of the particles in the coating solution. Ultrasonic or high shear stirring can be used to help disperse and prevent particle sedimentation or agglomeration.

[0033] During the surface coating process, PVA film is used as the middle layer and PMMA is used as the covering layers on both sides. The PMMA films are sent to the Corona treatment equipment for surface activation. Corona treatment generates corona discharge between electrodes through high voltage. The high-energy ions, free radicals and ozone generated by corona discharge will react with the molecules on the surface of the PMMA film, breaking the molecular chains and introducing polar groups, thereby significantly improving the surface energy of the PMMA film and enhancing its adhesion to the PVA film.

[0034] Typically, each piece of PMMA film is treated in the Corona device for 5-10 seconds, depending on the film's thickness, surface quality, and required activity level. A layer of UV-curable adhesive is applied to the bonding surface of the PMMA film and the PVA film. The adhesive is used to bond the PMMA film and the PVA film. The PMMA films treated with Corona are bonded to both sides of the PVA film. Since both sides of the PMMA film are treated with Corona, they can adhere better to the surface of the PVA film.

[0035] UV adhesive has good optical transparency and hardness, and can effectively enhance the adhesion between film layers to ensure the stability of the entire multi-layer structure.

[0036] The film coated with UV adhesive and bonded is exposed to UV light, and then AG particles are coated, and then enters the UV curing equipment after the AG particles are coated; the UV curing process includes at least three UV curing devices, namely UV-1, UV-2, and UV-3, and each device adjusts the exposure time and light source intensity according to the thickness of the film, the coating type and the required curing effect; in each curing device, ultraviolet irradiation will trigger the reaction of the photoinitiator in the adhesive to form a strong adhesive layer, and the curing time is preferably 5-20 seconds per device.

[0037] After curing, the coating should be cooled at room temperature to ensure that the coating is stable. If further enhancement of the coating's adhesion or wear resistance is required, plasma cleaning or surface treatment can be performed; the coating's uniformity, thickness, and surface defects are then checked using automated optical inspection (AOI).

[0038] Finally, the coated substrate is wound and reeled through a cloth storage machine for subsequent packaging, transportation or direct application.

[0039] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An anti-glare PMMA polarizer, characterized in that: include: PMMA optical film substrate; The surface of the substrate is provided with an anti-glare coating; The anti-glare coating comprises acrylate prepolymer, acrylate monomer, photoinitiator, surfactant and silicon particles; The acrylate prepolymer and acrylate monomer are added to a solvent and mixed, then a photoinitiator and a surfactant are added to form a first mixed solution, and finally silicon particles are added to form a coating composition; The coating composition is provided with a pretreatment process before surface coating, and a multi-stage drying process is provided after coating, followed by a UV curing process; a protective film is applied after the UV curing process, and a pressure-sensitive adhesive is provided on the outer side of the protective film; Wherein, the PMMA is provided with two layers and is respectively attached to both sides of the PVA film.

2. The anti-glare PMMA polarizer according to claim 1, characterized in that: The solvent includes ketones, esters and benzenes.

3. The anti-glare PMMA polarizer according to claim 1, characterized in that: The photoinitiator is a free radical photoinitiator, and the photoinitiator polymerizes with the acrylate monomer under UV irradiation.

4. The anti-glare PMMA polarizer according to claim 1, characterized in that: The pretreatment process includes oven preheating and plasma cleaning of PMMA; Wherein, the plasma cleaning is performed on two layers of PMMA films before UV curing.

5. The anti-glare PMMA polarizer according to claim 1, characterized in that: The UV curing process includes: The PVA layer and the PMMA layer are bonded together by a UV curing adhesive, and the UV curing adhesive is cured under ultraviolet irradiation to form an adhesive layer.

6. The anti-glare PMMA polarizer according to claim 5, characterized in that: The UV curing process includes at least 3 curing devices.

7. The anti-glare PMMA polarizer according to claim 1, characterized in that: The protective film is attached to the surface of the coating layer and a pressure-sensitive adhesive is arranged on the outer side of the protective film.

8. The anti-glare PMMA polarizer according to claim 7, characterized in that: The pressure-sensitive adhesive has an adhesive force within 300 gf / 25 mm.

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