Anti-adhesion polaroid manufacturing process

Abstract

The invention discloses an anti-adhesion polaroid manufacturing process in the technical field of polaroids, and the anti-adhesion polaroid manufacturing process comprises the steps that a PMMA film containing smooth particles is prepared, the PMMA film comprises a base material face and a primer face opposite to the base material face, and the base material face and the primer face form a uniform microscopic protruding structure through the smooth particles; compounding the PMMA film with a stretched and dyed PVA film through a photocuring adhesive laminating process to form a polarizing film comprising the PVA film, the PMMA film and a TAC film; coating a pressure-sensitive adhesive on the surface of the compounded polarizing film, and compounding a protective film and a release film; according to the manufacturing process, the steps of attaching and tearing off the PE protective film are omitted; according to the invention, the uniformly distributed AB smooth particles form a protruding structure to reduce the friction coefficient, and the steps of attaching and tearing off the PE protective film are omitted, so that the production cost is effectively reduced, the production efficiency is improved, the abnormal gluing is avoided, and the practical value is remarkable.

Description

Technical Field

[0001] The present invention relates to an anti - adhesion manufacturing process for polarizing films, belonging to the technical field of polarizing films. Background Art

[0002] With the rapid development of the consumer electronics market, as a key component of liquid crystal displays, the market demand for polarizing films has been continuously increasing. In traditional polarizing film production processes, it is usually necessary to laminate a PE protective film between the PVA film and the TAC film to prevent adhesion, and then remove the PE film before coating the pressure - sensitive adhesive. This process not only increases production costs but also reduces production efficiency. In addition, the use of the PE film may also cause abnormal gluing, affecting product quality. To solve these problems, existing technologies have tried to reduce the friction coefficient by adding slip particles to the substrate to prevent adhesion without using the PE protective film. However, these methods still have certain limitations in practical applications, such as uneven distribution of slip particles and inaccurate control of the friction coefficient, resulting in unsatisfactory anti - adhesion effects.

[0003] Therefore, there is an urgent need to develop a new anti - adhesion manufacturing process for polarizing films to solve the above problems and improve production efficiency and product quality. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art. To solve the above - mentioned technical problems, the present invention is implemented by adopting the following technical solutions: Provide an anti - adhesion manufacturing process for polarizing films, including the following steps: Prepare a PMMA film containing slip particles. The PMMA film includes a substrate surface and a primer surface opposite to the substrate surface. The substrate surface and the primer surface form a uniform microscopic protrusion structure through the slip particles; Laminating the PMMA film with a stretched and dyed PVA film through a photocuring adhesive lamination process to form a polarizing film containing a PVA film, a PMMA film, and a TAC film; Coat a pressure - sensitive adhesive on the surface of the laminated polarizing film, and laminate a protective film and a release film; Among them, the manufacturing process omits the steps of laminating and removing the PE protective film.

[0005] Further, the slip particles are AB particles, and the addition amount is 0.1% - 5% of the total mass of the PMMA film.

[0006] Further, the PMMA film includes: the thickness of the PMMA film is set to 40 ± 3μm; During the preparation process, the slip particles are uniformly dispersed in the PMMA substrate through a blending process.

[0007] Furthermore, the photocuring adhesive is a UV glue. The photoinitiator type of the UV glue is free radical type or cationic type, and the ultraviolet irradiation wavelength is 200 - 400 nm.

[0008] Furthermore, the curing time of the UV glue is 1 - 10 seconds.

[0009] Furthermore, the coating thickness of the pressure - sensitive adhesive is 10 - 30 μm, and it is subjected to hot - air drying or infrared pre - curing treatment.

[0010] In a second aspect, an anti - sticking polarizer is prepared by the anti - sticking polarizer manufacturing process mentioned in the first aspect. The polarizer includes a PVA film, a PMMA film containing slip particles, and a TAC film which are laminated in sequence, and the surface roughness Ra of the PMMA film is 0.05 - 0.3 μm.

[0011] Furthermore, the adhesion strength between the PMMA film and the PVA film is ≥200 gf / 25 mm through peel testing.

[0012] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: In the present invention, the protrusion structure formed by uniformly distributed AB slip particles reduces the friction coefficient, and the steps of laminating and tearing off the PE protective film are omitted, effectively reducing the production cost, improving the production efficiency, and avoiding abnormal gluing, which has significant practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 The figure shows the structure diagram of the polarizer containing slip particles provided by the present invention; Figure 2 The figure shows the process flow diagram of the manufacturing process provided by the present invention; Figure 3 The figure shows the composition diagram of the PMMA containing AB agent provided by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0014] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the protection scope of the present invention.

[0015] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", and "connection" 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 directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific situations. Embodiment

[0016] The present application provides an anti - adhesion polarizer manufacturing process, which includes preparing a PMMA film containing slip particles. The PMMA film includes a substrate surface and a primer surface opposite to the substrate surface. The substrate surface and the primer surface form a uniform microscopic protrusion structure through the slip particles; laminating the PMMA film with a stretched and dyed PVA film through a photocuring adhesive lamination process to form a polarizing film including a PVA film, a PMMA film, and a TAC film; coating a pressure - sensitive adhesive on the surface of the laminated polarizing film, and laminating a protective film and a release film; wherein, the manufacturing process omits the steps of laminating and removing a PE protective film.

[0017] The AB slip particles refer to organosilicon - modified polymer microparticles with a specific particle size distribution, which can be uniformly dispersed in the PMMA matrix by a melt - blending method to form a microscopic protrusion structure on both sides of the film material. The UV adhesive lamination process refers to using an acrylate - based adhesive containing a photoinitiator and utilizing ultraviolet light radiation to initiate a rapid polymerization reaction to achieve solvent - free bonding of optical film materials. The protrusion structure refers to the surface microscopic morphology formed by the exposure of particles, which can reduce the contact area and thus reduce the interfacial friction force. The composite protective film refers to a transparent polymer layer with a mechanical support function, which is retained in the final product to provide transportation protection.

[0018] Specifically, by regulating the distribution density of AB particles on both sides of the PMMA film, a controllable rough surface is formed to keep an appropriate gap between stacked film materials. Chemical bonding is generated during the curing process of the UV adhesive to ensure the reliable bonding between the PVA layer and the modified PMMA. The lamination process is implemented by a continuous roll - pressing method, and the photocuring step is completed synchronously with the lamination operation to form a laminated structure without a protective film. The subsequent coating process constructs a functional layer on the surface of the formed polarizing film to maintain the mechanical strength of the product and avoid process contamination.

[0019] The addition amount of the AB slip particles is controlled within the range of 0.1% - 5% of the total mass of the PMMA film; wherein, the AB slip particles refer to composite microparticles composed of an acrylate - based polymer and a styrene - butadiene copolymer, and can be specifically mixed and dispersed by a twin - screw extruder at the melting stage of the PMMA resin. These particles form a micron - scale protrusion structure on the substrate surface, creating an air gap between the film layers to reduce the contact area. The lower limit of the addition amount is set at 0.1% mass ratio to ensure that the particles reach the critical distribution density per unit area; the upper limit is controlled at 5% mass ratio to avoid particle agglomeration forming a light - scattering center.

[0020] Specifically, when the content of the AB smooth particles is less than 0.1%, the particle spacing is too large, resulting in discontinuous surface protrusion structures and unable to effectively reduce the friction coefficient between the film layers. When it exceeds 5%, the van der Waals force between the particles is enhanced, causing local agglomeration and resulting in diffuse reflection of light within the film. By precisely limiting the addition amount within this range, the original light-transmitting characteristics of the PMMA substrate are maintained, and a physically barrier structure with a uniform distribution is formed on the surface. This process controls the melt rheology during the extrusion molding stage, enabling the particles to be arranged directionally along the extrusion direction, and simultaneously forming an anti-sticking structure on the surface of the substrate and the bottom coating.

[0021] The thickness range of the PMMA film is controlled to be 40 ± 3 μm, while meeting the requirements that the total light transmittance is not less than 90% and the haze is not more than 1.3%. The thickness range of the PMMA film is a structural parameter of the film material achieved through the extrusion molding process, and specifically, it can be realized by using a multi-layer co-extrusion technology in combination with precise die size control. This thickness range ensures mechanical strength while avoiding attenuation of the light transmittance. Among them, the total light transmittance is a light-transmitting performance index achieved by adjusting the polymer crystallinity, and specifically, it can be realized by using high-purity raw materials in combination with a melt filtration process. This index ensures the basic function of the film layer as an optical protection material. Among them, the haze is a light scattering parameter controlled by regulating the surface flatness, and specifically, it can be realized by using a polishing roll calendering process in combination with a surface coating treatment. This parameter limit effectively suppresses the phenomenon of light diffuse reflection.

[0022] Under the process conditions of omitting the PE protective film, by controlling the substrate thickness within a specific range, the ability of the film layer to resist mechanical stress during the lamination process is maintained, and the deterioration of the light-transmitting performance caused by excessive thickness is avoided. The establishment of the total light transmittance index enables this protective layer to still maintain the basic transmission efficiency of the optical system after canceling the auxiliary anti-sticking structure. The limitation of the haze parameter combined with the control of the surface microtopography ensures imaging clarity while reducing the friction coefficient. The synergistic effect of the three solves the problems of light-transmission loss and image blurring caused by canceling the protective film in the traditional process.

[0023] In the UV glue bonding process, a photoinitiator is used to achieve rapid curing of the adhesive under ultraviolet irradiation, and the curing time is controlled within the range of 1 - 10 seconds; among them, the photoinitiator refers to a compound that can generate active free radicals or cations after absorbing ultraviolet energy, and specifically, benzophenone-based and thioxanthone-based substances can be used to achieve this. These substances can trigger the polymerization reaction of monomers under the excitation of ultraviolet light with a specific wavelength. Ultraviolet irradiation refers to using a light source system with a wavelength of 200 - 400 nm, and specifically, a high-pressure mercury lamp or an LED ultraviolet light source can be used to achieve this, and the phase transition of the adhesive is achieved by precisely controlling the irradiation energy. The curing time within the range of 1 - 10 seconds refers to the total time taken for the liquid adhesive to transform into a solid bonding layer, and specifically, it is achieved by adjusting the combined parameters of the ultraviolet intensity and the irradiation distance. This time window can not only ensure sufficient cross-linking of molecular chains but also match the running speed of the continuous production line.

[0024] Multiple groups of high-power mercury lamp light sources are arranged in the ultraviolet irradiation equipment, so that the adhesive coating layer containing the photoinitiator continuously receives irradiation during the conveying process. When the substrate passes through the irradiation area at a linear speed of 0.5 - 2 m / s, the photoinitiator absorbs ultraviolet light in the 365 nm band and decomposes to generate active free radicals, triggering the chain polymerization reaction of acrylate monomers. The adhesive completes the transformation from liquid to gel state within 3 seconds and achieves complete curing to form a stable bonding interface within 7 seconds. This process replaces the water evaporation and chemical cross-linking steps that take more than 30 minutes in the traditional water glue process, and at the same time eliminates the operation units such as soaking, rinsing, and drying in the alkali washing process.

[0025] This application further proposes a process control scheme for achieving a peeling test adhesion strength of ≥200 gf / 25 mm between the PMMA film and the PVA film without a PE protective film; among them, the peeling test is a quantitative detection method for the interfacial bonding force of the composite film layer, and specifically, a 180° peeling strength tester can be used to measure the force value required to separate the two layers of materials at a constant rate, and the test result directly reflects the interfacial bonding stability after the UV glue is cured. Among them, the threshold setting of the adhesion strength ≥200 gf / 25 mm is achieved through the coordinated optimization of the UV glue material formula and the curing process. For example, a UV glue system containing a specific photoinitiator is used, and under ultraviolet irradiation, the glue layer rapidly cross-links to form a dense network structure, thereby ensuring that the interfacial bonding force meets the process requirements. Among them, the UV glue bonding process refers to under the condition of an ultraviolet energy density of 100 - 500 mJ / cm², triggering the polymerization reaction of the glue layer through a photoinitiator, and completing the lamination of the PMMA film and the PVA film within 1 - 10 seconds. This process can avoid the risk of interlayer separation caused by incomplete curing of the glue layer.

[0026] By adjusting the types and addition ratios of photoinitiators in the UV glue, the crosslinking rate and final mechanical properties of the glue layer under the action of ultraviolet light are controlled, so that the bonding strength between the PMMA film and the PVA film can still be maintained at a level of ≥ 200 gf / 25 mm in the peel test without a PE protective film. At the same time, the uniform distribution of AB slip particles on the surface of the PMMA film avoids adhesion after lamination by reducing the friction coefficient between the film layers, and their particle size and distribution density are controlled within a range that can reduce friction without affecting the wetting and spreading of the UV glue. Thus, the composite film can still maintain a stable interlayer structure after removing the PE film, preventing interface delamination during subsequent cutting or edge grinding processes.

[0027] The monomer transmittance refers to the effective passing amount of polarized visible light, which can be specifically achieved by optimizing the material composition and surface treatment process to maintain optical uniformity while ensuring the basic brightness. Among them, the polarization degree is an index of polarization efficiency, which can be specifically achieved by controlling the accuracy of the lamination process and the interface bonding quality to avoid light leakage caused by uneven stress distribution or lamination defects in the film layer. Among them, the warpage angle refers to the deformation degree of the composite film layer under the action of thermal stress, which can be specifically achieved by adjusting the thermal expansion coefficient matching of each layer of material to control the shrinkage difference between different film layers; by setting double indexes of optical performance benchmark and physical deformation limit, the product performance stability is ensured in the case of omitting the protective film. The optical performance index is achieved by optimizing the material light transmittance and the lamination process accuracy to ensure the effectiveness of the polarization function; the warpage angle limit is achieved by adjusting the thermal shrinkage matching of each layer of material to offset the change in thermal stress distribution caused by removing the protective film. The two indexes work together to not only meet the requirements of the display device for brightness and contrast, but also avoid lamination failure or optical distortion caused by film layer deformation.

[0028] This application further proposes a technical solution of forming a surface roughness Ra of 0.05 - 0.3 μm and a friction coefficient ≤ 0.3 on the surface of the PMMA film. Among them, the surface roughness Ra refers to the arithmetic mean deviation of the microscopic profile of the film material surface, which can be specifically achieved by adding AB slip particles during the film formation process to form a uniformly distributed micron-scale protrusion structure, and this feature controls the surface morphology by adjusting the particle size distribution and addition ratio. The friction coefficient refers to the sliding resistance characteristics between two contact surfaces, which can be specifically achieved by regulating the height distribution and density of the surface protrusions to form a self-lubricating interface, and this feature is achieved by the combination of particle morphology design and surface treatment process.

[0029] Specifically, when the surface roughness Ra is controlled within the range of 0.05 - 0.3 μm, the formed micro-protrusion structure can effectively reduce the actual contact area between the film layers, while avoiding the decrease in light transmittance or the increase in haze caused by excessive surface roughness. When the Ra value is lower than the lower limit, the surface is too smooth and prone to interlayer adsorption; when it exceeds the upper limit, obvious light scattering occurs. Under the synergistic effect of the friction coefficient being limited to ≤ 0.3, the surface protrusions and the substrate material form a rolling friction effect, causing the film layer to slide rather than stick during winding or stacking. This dual control mechanism replaces the physical isolation function of traditional PE protective films on the premise of maintaining a total light transmittance ≥ 90% and a haze ≤ 1.3%.

[0030] In some specific embodiments, the AB slip particles can be silica or silicone materials with a particle size of 0.1 - 3 μm. For example, the particles can be uniformly dispersed on the substrate surface and the primer surface through a twin-screw extrusion process. After film formation, the surface roughness can be measured by a white light interferometer, and the dynamic friction coefficient can be tested by the horizontal sliding method.

[0031] Through the above technical solutions, the present application realizes the stable separation between the polarizing film layers without a PE protective film, prevents interfacial adhesion during winding and storage, and at the same time maintains the optical indexes of a light transmittance ≥ 90% and a haze ≤ 1.3%, solving the problems of abnormal gluing and appearance defects caused by omitting the protective film in the traditional process.

[0032] The surface roughness Ra refers to the arithmetic mean deviation of the microscopic morphology of the PMMA film surface, which can be specifically achieved by adding AB slip particles to form a uniformly distributed micron-scale protrusion structure. This parameter range can not only avoid the increase in interlayer adsorption force caused by overly smooth surface, but also prevent light scattering caused by too high roughness. The friction coefficient refers to the resistance ratio during the relative sliding between the film layers, and specifically, by adjusting the AB particle content and particle size distribution, the friction coefficient is ≤ 0.3, thereby reducing the sliding resistance between the film layers during winding.

[0033] Specifically, when the surface roughness Ra is 0.05 - 0.3 μm, the formed micron-scale protrusion structure generates a controllable gap between the film layers, effectively reducing the contact area. This gap can block the intermolecular adsorption effect without significantly affecting the optical uniformity. The technical requirement of the friction coefficient ≤ 0.3 is achieved by optimizing the particle dispersibility, enabling the film layer to have an appropriate sliding ability during the lamination process. The synergistic effect of these two parameters enables the polarizing film to avoid winding adhesion and abnormal gluing without a PE protective film, while maintaining a total light transmittance of more than 90%.

[0034] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. An anti-adhesion polarizer manufacturing process, characterized in that, The following steps are involved: Preparing a PMMA film containing slippery particles, wherein the PMMA film comprises a substrate surface and a primer surface opposite to the substrate surface, wherein the substrate surface and the primer surface form a uniform microscopic protrusion structure through the slippery particles; Compounding the PMMA film with the stretched and dyed PVA film through a light-curing adhesive bonding process to form a polarizing film comprising the PVA film, the PMMA film and the TAC film; Coating a pressure-sensitive adhesive on the surface of the composite polarizing film, and composite a protective film and a release film; The manufacturing process omits the steps of laminating and removing the PE protective film.

2. The anti-sticking polarizer manufacturing process according to claim 1, wherein, The lubricating particles are AB particles, and the added amount thereof is 0.1%-5% of the total mass of the PMMA film.

3. The anti-sticking polarizer manufacturing process according to claim 1, wherein, The PMMA film comprises: the PMMA film thickness is set to 40±3 μm; During the preparation process, the slippery particles are evenly dispersed in the PMMA substrate through a blending process.

4. The anti-sticking polarizer manufacturing process according to claim 1, characterized in that, The light-curing adhesive is UV glue, the photoinitiator type of the UV glue is free radical type or cationic type, and the ultraviolet irradiation wavelength is 200-400nm.

5. The anti-sticking polarizer manufacturing process according to claim 4, characterized in that, The curing time of the UV glue is 1-10 seconds.

6. The anti-sticking polarizer manufacturing process according to claim 1, characterized in that The pressure-sensitive adhesive has a coating thickness of 10-30 μm and is subjected to hot air drying or infrared pre-curing treatment.

7. An anti-sticking polarizer is prepared by the anti-sticking polarizer manufacturing process described in any one of claims 1-6, and is characterized in that, The polarizer comprises a PVA film, a PMMA film containing lubricating particles and a TAC film which are compounded in sequence, and the surface roughness Ra of the PMMA film is 0.05-0.3 μm.

8. The polarizer according to claim 7, wherein The bonding strength between the PMMA film and the PVA film is greater than or equal to 200 gf / 25 mm through a peeling test.

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