A PDLC film edge sealing method

Abstract

The present application discloses a PDLC film edge sealing method, comprising the following steps: first, pre-treating the edges of the PDLC film by half-cutting to form an edge sealing step of a predetermined width; second, cutting out a matching edge sealing film pattern according to the outer contour of the PDLC film so that the edge sealing film and the edge of the PDLC film precisely correspond; then, attaching the cut edge sealing film pattern to the edge of the PDLC film, and rolling and compacting it back and forth along the pre-fixed area with a roller; finally, placing the pre-treated PDLC film into a vacuum bag, laminating it, and further curing it. The edge sealing film of the present application is suitable for PDLC films of any shape and is not affected by the shape or curvature of the glass; and through the synergistic effect of hot rolling pre-fixation and high temperature and high pressure lamination process, a firm and stable bond is formed between the edge sealing film and the PDLC film, effectively avoiding edge peeling; in addition, bubbles caused by dust can be avoided, thereby improving the bonding firmness and bending resistance of the edge sealing.

Description

Technical Field

[0001] The present invention relates to the technical field of dimming films, and in particular to a PDLC film edge sealing method. Background Art

[0002] Switchable glass is a dimming product created by hot-pressing a polymer dispersed liquid crystal (PDLC) film and a film between two sheets of glass. The PDLC film performs the key dimming function, while the adhesive layer acts as a bonding agent. To achieve specific performance requirements, most current switchable glass is laminated with polyvinyl butyral (PVB) film. PVB adhesive contains a certain amount of plasticizers and other small molecule additives, which effectively improve the material's cold and heat resistance. However, when the PDLC film and PVB adhesive are hot-pressed under high temperature and high pressure to form switchable glass, the polymer dispersed liquid crystal layer in the PDLC film comes into direct contact with the PVB adhesive. The plasticizers and other small molecules in the PVB adhesive gradually destroy the structure of the PDLC film, causing its haze effect to deteriorate and eventually fail. This can cause partial dimming failure and ultimately render the entire product useless. Therefore, an effective method is needed to prevent direct contact between the PVB adhesive and the liquid crystal.

[0003] To address the failure problem caused by PVB adhesive contacting the liquid crystal, existing technologies currently offer two main improvement solutions, but both have significant limitations. The first solution involves applying edge-sealing adhesive to the edges of the PDLC film, which cures at high temperatures to form a solid coating that blocks contact between the PVB adhesive and the liquid crystal. However, this solution requires high toughness from the edge-sealing adhesive. If this is insufficient, it can break easily during transportation or when used on large-curved car sunroofs. Furthermore, strict cleanliness requirements are imposed on the edge-sealing steps during operation, otherwise the adhesive can easily become loose and fall out. The second solution involves applying a double layer of polyethylene terephthalate (PET) tape to the edges of the PDLC film, blocking contact between the PVB adhesive and the liquid crystal. However, this solution is complex and requires double layers of tape to be applied top and bottom, with some adhesive cut off at the four corners to prevent contact with the liquid crystal. Moreover, for irregular-shaped films, especially those with large edge curvatures, the PET tape cannot be adhered to the shape due to its fixed adhesive position. Wrinkles are easily generated at the corners, affecting the edge sealing quality. At the same time, the part of the two layers of edge sealing tape that extends out of the film will occupy the width of the glass filling, which will bring certain restrictions to the subsequent glass processing and assembly. The possibility of wrinkles and other large deformation defects caused by the bonding of the two layers of edge sealing tape is high, affecting the edge sealing quality. Summary of the Invention

[0004] In order to solve the problems of the risk of fracture caused by insufficient toughness of the edge-sealing adhesive in the traditional PDLC film edge-sealing process, strict requirements for cleaning the edge-sealing steps, complex multi-layer adhesive structure and poor adaptability of the bonding process. This application proposes a PDLC film edge-sealing technology, which only requires a single layer of edge-sealing film on the edges of the PDLC film. At the same time, the edge-sealing width of the edge-sealing film does not need to extend beyond the PDLC film sheet, and is suitable for PDLC films of any shape, and is not affected by the shape and curvature of the glass; and through the hot rolling pre-fixing process and the high-temperature and high-pressure curing and laminating process, a firm and stable bond is formed between the edge-sealing film and the PDLC film, which effectively avoids edge peeling, reduces the possibility of large deformation defects such as wrinkles on the edge-sealing film, and improves the bonding firmness and bending resistance of the edge sealing. The technical solutions provided by this application are as follows:

[0005] In one aspect, the present application provides a PDLC film edge sealing method, comprising:

[0006] Half-cut pretreatment: half-cut pretreatment is performed on the edges of the PDLC film to form a sealing step of a preset width; wherein the cutting depth is to remove the upper base layer of the PDLC film;

[0007] Edge sealing film cutting: based on the outer contour of the PDLC film, cutting the edge sealing film into an edge sealing film pattern that matches the outer contour of the PDLC film;

[0008] Film positioning and pre-fixing: The cut edge-sealing film pattern is attached to the edge of the PDLC film and preheated and compacted by rolling along the pre-fixing area with a roller; wherein the pre-fixing area is the area between the edge of the protective film and the edge of the upper substrate layer;

[0009] Lamination and secondary curing: laminating the pretreated PDLC film and the glass substrate via a PVB interlayer to form a sandwich structure, and then placing the sandwich structure in a first autoclave for secondary curing at a preset temperature and a preset pressure; or

[0010] The pretreated PDLC film is placed in a vacuum bag and then placed in a second autoclave for initial curing under the negative pressure generated by vacuum extraction and the cooperation of the second autoclave; the cured PDLC film is then laminated with the glass substrate using a PVB interlayer to form the sandwich structure, and the sandwich structure is placed in the first autoclave for further curing under preset temperature and pressure conditions.

[0011] In some specific embodiments, the operating temperature of the roller is 90-120° C., the rolling speed is 0.5-6 m / min, and the pressure applied to the pre-fixed area is 10-30 N.

[0012] In some specific embodiments, the preset temperature is 125-145° C., and the preset pressure is 0.8-1.1 MPa.

[0013] In some specific embodiments, the size of the protective film is smaller than that of the upper substrate layer, and the thickness thereof is 20-80 μm.

[0014] In some specific embodiments, when the roller is in operation, the distance between the roller and the edge of the upper substrate layer and the edge of the protective film is 0.1 mm to 1 mm;

[0015] The ratio of the width of the pre-fixing area to the width of the edge sealing step is (1.01-1.6):1.

[0016] In some specific embodiments, the width of the pre-fixing area is 2-50 mm, and the width of the edge sealing step is 1-70 mm.

[0017] In some specific embodiments, the edge sealing film includes a substrate layer and an adhesive coated on the surface of the substrate layer;

[0018] The material of the substrate layer is selected from one or more of polyethylene terephthalate and polyimide;

[0019] The semi-curing temperature of the viscose is 90-110°C;

[0020] The adhesive is selected from epoxy resin adhesive.

[0021] In some specific embodiments, the thickness of the substrate layer is 20-95 μm;

[0022] The thickness of the epoxy resin adhesive layer is 5-80 μm.

[0023] In some specific embodiments, the thickness of the edge sealing film is 25-100 μm;

[0024] The thickness of the PVB interlayer is 0.38-1.52 mm.

[0025] In some specific embodiments, the horizontal distance from the edge of the protective film to the edge of the lower substrate layer is 5-20 mm.

[0026] In some specific embodiments, when the roller is in operation, the width of the contact surface between the roller and the pre-fixed area is 3-15 mm.

[0027] By adopting the above technical solution, the PDLC film edge sealing method provided in this application has the following beneficial effects:

[0028] This application uses epoxy resin film as the edge sealing material. This material does not chemically react with liquid crystal, thus effectively preventing the PDLC film from failing in the dimming area during the subsequent lamination process.

[0029] The process is simple, requiring only a single layer of edge-sealing film to complete the edge-sealing operation. Furthermore, the edge-sealing width does not need to extend beyond the PDLC film, eliminating the tedious process of additional cutting and precise control of the edge-sealing width, further enhancing the convenience of construction.

[0030] This application utilizes the synergistic effect of hot rolling pre-fixation and high-temperature and high-pressure curing lamination processes to process different areas of the edge-sealing film in two steps, allowing the edge-sealing film to be firmly attached to the PDLC film, effectively avoiding edge peeling, reducing the possibility of large deformation defects such as wrinkling of the edge-sealing film, and improving the bonding strength and bending resistance of the edge-sealing. Among them, the hot rolling pre-fixation process initially fixes the position of the edge-sealing film, allowing it to be tightly bonded to the PDLC film, facilitating transportation and avoiding displacement during handling; the high-temperature and high-pressure curing lamination process further enhances the bonding strength of the two, making the edge-sealing effect stable and long-lasting, improving the bonding strength and bending resistance of the edge-sealing, and reducing the risk of edge peeling.

[0031] The edge-sealing film used in this application is fully coated, allowing it to be cut to any desired PDLC film shape to meet the needs of different scenarios and design solutions. Whether it's a regular rectangle or an irregular, special shape, pre-fixing and edge-sealing can be achieved, expanding the application range of this technology and making it useful in different types of PDLC film packaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0033] Figure 1 A schematic diagram of the pre-fixing stage of the PDLC film edge sealing method provided in an embodiment of the present application;

[0034] Figure 2 Schematic diagram of the secondary curing stage of the PDLC film edge sealing method provided in the embodiment of the present application Figure 1 ;

[0035] Figure 3 Schematic diagram of the secondary curing stage of the PDLC film edge sealing method provided in the embodiment of the present application Figure 2 ;

[0036] Figure 4 Schematic diagram of the edge-sealing film and the pattern of the edge-sealing film after cutting provided in an embodiment of the present application.

[0037] The following is a supplementary description of the accompanying drawings:

[0038] 11-upper substrate layer; 12-lower substrate layer; 2-polymer dispersed liquid crystal layer; 3-protective film; 4-edge-sealing film; 41-base material layer; 42-adhesive; 5-silver paste; 6-PVB interlayer; 71-pre-fixing area; 72-edge-sealing step; 8-roller; 10-vacuum bag; 101-vacuum nozzle. DETAILED DESCRIPTION

[0039] The following will be combined with the accompanying drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making any creative work are within the scope of protection of this application.

[0040] As used herein, "one embodiment" or "embodiment" refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present application. Throughout the description of this application, it should be understood that the terms "upper," "lower," "top," and "bottom," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely for ease of description and simplification. They do not indicate or imply that the referenced elements must have, be constructed, or operate in a specific orientation and are not to be construed as limiting the present application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly specifying the number of the referenced technical features. Thus, a feature designated "first" or "second" may explicitly or implicitly include one or more of the referenced features. Furthermore, the terms "first," "second," etc. are used to distinguish similar objects and are not necessarily used to describe a specific order or sequential sequence. It should be understood that such terms are interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein.

[0041] When a numerical range is disclosed herein, the above range is considered to be continuous and includes the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe a feature or characteristic, the ranges can be merged. In other words, unless otherwise indicated, all ranges disclosed herein should be understood to include any and all subranges included therein. For example, a specified range from "1 to 10" should be considered to include any and all subranges between a minimum of 1 and a maximum of 10. Exemplary subranges of the range 1 to 10 include, but are not limited to, 1 to 6.1, 3.5 to 7.8, 5.5 to 10, etc.

[0042] See also Figures 1 to 4 The PDLC film edge sealing method provided in the embodiment of the present application includes:

[0043] Half-cut pretreatment: The edges of the PDLC film are subjected to half-cut pretreatment to form edge-sealing steps 72 of a preset width; wherein the cutting depth is sufficient to remove the upper substrate layer 11 of the PDLC film;

[0044] Edge sealing film cutting: Based on the outer contour of the PDLC film, the edge sealing film 4 is cut into an edge sealing film pattern that matches the outer contour of the PDLC film;

[0045] Film positioning and pre-fixing: The cut edge-sealing film pattern is attached to the edge of the PDLC film and preheated and compacted by rolling with a roller 8 along the pre-fixing area 71; the pre-fixing area 71 is the area between the edge of the protective film 3 and the edge of the upper substrate layer 11;

[0046] Lamination and secondary curing: The pre-treated PDLC film is laminated with the glass substrate via the PVB interlayer 6 to form a sandwich structure. The sandwich structure is then placed in an autoclave for secondary curing at a preset temperature and pressure.

[0047] Alternatively, the pretreated PDLC film is placed in a vacuum bag 10 and then placed in a second autoclave for initial curing under the negative pressure generated by vacuum extraction and the cooperation of the second autoclave; the cured PDLC film is then laminated with a glass substrate using a PVB intermediate film 6 to form a sandwich structure, and the sandwich structure is placed in a first autoclave for further curing under preset temperature and preset pressure conditions.

[0048] Specifically, the structure of the PDLC film is usually composed of two layers of transparent conductive materials (upper substrate layer 11 and lower substrate layer 12 respectively) sandwiching a polymer dispersed liquid crystal layer 2. The upper and lower substrate layers serve as carriers of the conductive layer, and a layer of PET protective film 3 is usually attached to the surface to prevent abrasions and scratches. The protective film 3 is removed before the final assembly; the surface of the conductive layer is coated with silver paste 5 to form electrodes to realize electrical signal transmission. The non-electrode layer structure and edge sealing process are the same but do not require the coating of silver paste 5; the polymer dispersed liquid crystal layer 2 serves as the main body of the dimming function, and controls light scattering or transmission by changing the arrangement direction of liquid crystal droplets through an external electric field. However, special attention should be paid to the plasticizer in the PVB intermediate film 6, because its contact with liquid crystal will cause the liquid crystal to dissolve or phase separate, thereby causing dimming failure. During the edge sealing process, the PDLC film is first placed flat on the work surface, and the edges of the PDLC film are pre-cut using high-precision laser cutting or CNC milling technology. The upper substrate layer 11 is accurately removed to form an edge sealing step structure of a preset width. The exposed lower substrate layer 12 can be used to make a transparent electrode as needed or completely remove the local liquid crystal to form an active bonding surface. The preset width of the edge sealing step 72 can be adjusted according to the width of the pre-fixed area 71. Generally, the width of the pre-fixed area 71 is greater than the width of the edge sealing step 72 to reduce the risk of wrinkles or glue overflow when the edge sealing film 4 is pre-fixed.

[0049] Secondly, the edge-sealing film pattern is customized and cut according to the shape of the PDLC film. Figure 4 The rectangle on the left in the figure represents the complete edge-sealing film 4 that has not been cut. The graphic in the middle position shows that the required edge-sealing film pattern is cut out on the complete edge-sealing film 4 according to the shape of different PDLC films. The graphic on the right shows that the cut edge-sealing film pattern is attached to the edge of the PDLC film. Since the edge-sealing film 4 is a whole-surface covering adhesive, it does not require folding and twisting when pasted on large-arc chamfers. It only needs to be placed on the PDLC film, which solves the pain point of the existing solution 2 that large rounded corners cannot be sealed, and is suitable for PDLC films of various shapes. At the same time, in the design of the edge-sealing film 4, long straight edges can be avoided. Instead, more curved edge designs can be used to adapt to glass with larger arch heights. A parametric curved edge modeling solution can be used, and geometric matching with high-arch glass can be achieved through CAD / CAM collaborative design, thereby improving the adaptability of the edge-sealing film.

[0050] Subsequently, the cut edge-sealing film pattern is precisely positioned in the target area, and a constant temperature roller 8 is used to carry out rolling hot compaction along the pre-fixed area 71, that is, within the limited interval between the edge of the protective film 3 and the edge of the upper base layer, to ensure that the edge-sealing film 4 is initially firmly attached. When the roller 8 is in operation, the surface temperature can be controlled in the range of 90-120°C, the rolling speed can be controlled in the range of 0.5-6m / min, and the downward pressure can be controlled in the range of 10-30N. This rolling heating mode achieves layer-by-layer curing of the bonding area through a gradient thermal field, which not only ensures the interfacial bonding strength between the upper base layer 11 and the edge-sealing film 4, but also realizes the successive heating, bonding, curing and cooling of the bonding area through the rolling heating method, reducing defects such as wrinkles in the bonding area and improving the bonding strength. At the same time, the successive heating and cooling also reduces the thermal impact of the non-bonding area during the pre-curing stage, which is beneficial to reducing defects such as excessive deformation of the film in the non-bonding area during the pre-curing stage, premature curing leading to reduced bonding during the later high-temperature curing bonding. At this time, a gap is left in the corresponding portion of the edge sealing step 72 in the non-bonding area during the pre-curing stage, which is conducive to the discharge of bubbles generated in the pre-fixed area 71, thereby further reducing the quality impact caused by bubbles retained in the finished product.

[0051] Finally, the PVB interlayer 6 is used for lamination packaging. The outer glass layer, dimming functional layer (including PDLC film component) and inner glass layer are assembled in sequence and then placed in an autoclave for high temperature and high pressure treatment. Figure 2 The arrow in the figure indicates the downward pressure exerted by the PVB interlayer 6 on the edge-sealing film 4. During this process, the edge-sealing film 4 on the lower substrate 12 is cured under the high temperature and pressure environment and the pressure of the PVB interlayer 6. The film in the pre-fixed area 71 undergoes a secondary heat-pressing cure, further improving bonding stability and effectively preventing physical contact or chemical migration between the PVB interlayer 6 and the liquid crystal medium, achieving a good edge-sealing effect.

[0052] In some specific embodiments, the preset temperature is 125-145°C and the preset pressure is 0.8-1.1 MPa. High temperature and high pressure facilitate rapid melting of the PVB interlayer 6 during the lamination process and ensure downward pressure on the edge-sealing film 4, thereby reducing the gap between the PET cut surface and the film during the edge-sealing process, minimizing the adverse effects of the gap.

[0053] Or, see Figure 3Before the lamination process, the pre-treated PDLC film is first placed in a vacuum bag 10 and then transferred to a second autoclave for initial curing treatment. A negative pressure environment is established by the vacuum nozzle 101, and combined with the closed pressurization conditions of the second autoclave, the edge-sealing film is completely cured before leaving the factory and forms a stable bond with the PDLC film. It can effectively prevent the silver paste 5 or the lower base layer 12 from absorbing dust and impurities due to environmental exposure during transportation, thereby avoiding bubble defects caused by impurities during secondary lamination. Evacuating the vacuum bag 10 is beneficial to the atmospheric pressure to ensure the downward pressure on the edge-sealing film 4, thereby reducing the gap between the PET section and the film during the edge sealing process, reducing the adverse effects of the gap.

[0054] In some specific embodiments, the operating temperature of the roller 8 is 90-120° C., the rolling speed is 0.5-6 m / min, and the pressure applied to the edge-sealing film 4 is 10-30 N.

[0055] Specifically, under relatively low temperature (90-120°C) and high speed (0.5-6 m / min) process conditions, a rolling heating and pressurizing curing method is employed in the pre-fixed area 71, effectively enhancing the bond strength between the upper base layer 11 and the edge-sealing film 4. The rolling heating method allows for sequential heating, curing, and cooling of the bonded area, helping to reduce defects such as wrinkles in the bonded area and improving bond strength. Furthermore, the sequential heating and cooling process reduces the thermal impact on the non-bonded areas during the pre-curing phase, mitigating defects such as reduced adhesion due to excessive deformation and premature curing of the film in these areas. Furthermore, the 10-30 N pressure applied to the edge-sealing film 4 ensures a tight fit between the film and the PET substrate, eliminating air and gaps at the interface, ensuring a uniform adhesive layer and avoiding localized adhesive gaps or excessive thickness. Appropriate pressure promotes the fluidity and wettability of the adhesive, enhancing the interfacial bonding between the film, the PET substrate, and the edge-sealing film 4, further improving the stability and sealing of the overall structure and preventing delamination and debonding during use. After this pre-fixation, the peeling strength between the upper base layer 11 and the edge-sealing film 4 can reach 0.07-0.2 N / m, which can ensure that the film will not fall off during subsequent processes and transportation.

[0056] In some specific embodiments, the size of the protection film 3 is smaller than that of the upper substrate layer 11 , and the thickness thereof is 20-80 μm.

[0057] Specifically, due to the extremely high requirements for the PDLC film's appearance, any friction scratches in the visible area are strictly prohibited. A PET protective film 3, preferably 50 μm thick, is applied to its surface to ensure a flawless appearance in the dimming area. This protective film 3 is slightly smaller than the upper substrate layer 11, and the uncovered area is used to bond the edge-sealing film 4. This prevents the edge-sealing film 4 from falling off while ensuring the peel strength meets process requirements. Finally, the protective film 3 is removed before lamination, ensuring the PDLC film's appearance integrity and reliable edge sealing.

[0058] In some specific embodiments, the distance between the roller 8 and the edge of the upper substrate layer 11 and the edge of the protective film 3 during operation is 0.1 mm to 1 mm;

[0059] The ratio of the width of the pre-fixing area 71 to the width of the edge sealing step 72 is (1.01-1.6):1.

[0060] Specifically, the distance between roller 8 and the edge of the upper substrate layer 11 and the edge of the protective film 3 during operation is controlled between 0.1mm and 1mm to further reduce thermal effects. If the right side of roller 8 exceeds this distance range, it will cause excessive deformation at the half-cut edge sealing step 72, which will adversely affect product quality. If the left side of roller 8 exceeds the boundary of edge sealing film 4, the edge will not be pressed, resulting in weak adhesion and possible warping.

[0061] In addition, the width ratio of the pre-fixing area 71 to the edge sealing step 72 is (1.01-1.6):1. By limiting the width of the pre-fixing area 71 to be larger, the suspended area during pre-fixing can be reduced, which is conducive to reducing the possibility of defects such as wrinkles in the film during pre-fixing.

[0062] In some specific embodiments, the width of the pre-fixing area 71 is 2-50 mm, optionally 2-15 mm, and the width of the edge sealing step 72 is 1-70 mm, optionally 1-20 mm.

[0063] In some specific embodiments, the edge-sealing film 4 includes a substrate layer 41 and an adhesive 42 coated on the surface of the substrate layer 41. The edge-sealing film 4, primarily composed of the substrate layer 41 and the adhesive 42 coated thereon, can provide good bonding strength in the pre-fixed area during pre-fixed bonding, while also providing a certain degree of shape stability and suitable deformation resistance (preventing excessive deformation, wrinkling, and other defects due to heat) in the non-pre-fixed area 71. This allows one end of the edge-sealing film 4 to be fixed to the upper base layer 11 for pre-bonding, while the other end maintains free contraction.

[0064] The material of the substrate layer 41 is selected from one or more of polyethylene terephthalate (PET) and polyimide (PI). The substrate layer 41 can be made of one or more high-strength polymers such as PET or PI, whose high modulus properties can effectively enhance the mechanical bearing capacity of the film.

[0065] The semi-curing temperature of the adhesive 42 is 90-110°C. Selecting a suitable semi-curing temperature of the adhesive 42 is beneficial to the film positioning and bonding of the edge sealing film 4 in the pre-fixing stage, as well as generating sufficient bonding strength during roller pressing and heating.

[0066] The adhesive 42 is selected from an epoxy resin adhesive system. The adhesive 42 is selected from an epoxy resin adhesive system (such as a toughened modified and high-temperature curing epoxy adhesive or an anhydride-promoted epoxy adhesive), and its adhesive properties are activated under a specific hot pressing process to achieve a stable bond with the upper and lower substrate layers.

[0067] In some specific embodiments, the thickness of the substrate layer 41 is 20-95 μm;

[0068] The thickness of the epoxy resin adhesive layer is 5-80 μm.

[0069] Specifically, the thickness of the substrate layer 41 of the edge-sealing film 4 ranges from 20 to 95 μm, serving as both a carrier for the adhesive 42 and a barrier to prevent contact between the PVB interlayer 6 and the liquid crystal. Because the PDLC film requires sealing on all sides to completely isolate it from foreign matter, there are at least two overlap points of the edge-sealing film 4. Excessive thickness of the substrate layer 41 can create gaps at these overlaps, forming channels for plasticizer to intrude into the liquid crystal. As a carrier for the adhesive 42, its thickness is appropriate to provide support for the edge-sealing film 4 during half-edge pre-fixing and bonding, while also preventing excessive deformation outside the pre-fixing area 71 due to heat. If the thickness is too thin, it will be difficult to resist excessive deformation caused by heat outside the pre-fixing area 71. Excessive thickness can result in excessive gaps outside the pre-fixing area 71, making deformation difficult and difficult to meet practical application requirements.

[0070] During the gluing process (42), the epoxy resin adhesive layer is controlled to have a thickness within a range of 5-80 μm. This gluing process (42) utilizes a hot roller (8) for pre-curing, and complete curing during the lamination process. Alternatively, curing is achieved by heating under vacuum and complete curing during the lamination process. This serves to block the path between the edge-sealing film (4) and the upper substrate layer (11). For epoxy resin adhesives, excessively thick adhesive layers can easily lead to adhesive overflow, while too thin a thickness can result in poor bonding stability. Therefore, to balance support performance and bonding effectiveness, it is more appropriate to control the adhesive layer thickness within a range of 5-80 μm.

[0071] In some specific embodiments, the thickness of the edge-sealing film 4 is 25-100 μm. Specifically, the overall thickness of the edge-sealing film 4 is controlled between 25-100 μm. If the thickness of the edge-sealing film 4 is too high, a step will be formed at its starting point when it is bonded to the PDLC film. In the subsequent lamination process, the extrusion applied by the outside world will cause stress concentration. After a certain period of time, the stress concentration area will easily form an indentation on the PDLC film, and in severe cases it may even cause the conductive layer of the PDLC film to break. On the contrary, if the thickness of the edge-sealing film 4 is too low, the thickness of the substrate layer 41 and the adhesive 42 cannot be reasonably distributed, thereby affecting the performance and stability of the entire membrane structure.

[0072] The thickness of the PVB interlayer 6 is 0.38-1.52 mm. Preferably, the thickness of the PVB interlayer 6 is 0.38 mm, 0.76 mm, 1.14 mm, or 1.52 mm, and 0.38 mm is preferred in automotive dimming skylights.

[0073] In some specific embodiments, the horizontal distance from the edge of the protective film 3 to the edge of the lower substrate layer 12 is 5-20 mm. This distance is greater than the edge-sealing width and can effectively prevent the edge-sealing film 4 from adhering to the protective film 3 during the lamination process, thereby ensuring the lamination accuracy and stability of the entire film structure and preventing a series of problems that may be caused by the edge-sealing film 4 adhering to the protective film 3, such as poor lamination, appearance defects, and performance problems that may occur during subsequent use.

[0074] In some specific embodiments, when the roller 8 is in operation, the width of the contact surface between the roller 8 and the pre-fixed area 71 is 3-15 mm. The roller 8 cannot deviate to the position of the protective film 3 during operation to ensure that the roller 8 completely covers the contact surface with the edge-sealing film 4. The width range is between 3-15 mm. If the width is too small, reliable peel strength cannot be provided. If the width is too large, it will exceed the half-cut of the film, which is not practical.

[0075] The PDLC film edge sealing method disclosed in the present application adopts an edge sealing film composed of a substrate layer 41 and an adhesive 42 of appropriate thickness, that is, it can provide good bonding strength in the pre-fixed area 71 during pre-fixed bonding, and at the same time provide a certain stable shape ability in the non-pre-fixed area during pre-fixed bonding, and has appropriate anti-deformation ability (to avoid excessive deformation due to heat, wrinkles and other defects of the film); the above-mentioned pre-fixed bonding method of bonding one end to the substrate layer 11 and the other end being non-fixed and freely shrinking is adopted, and at the same time, the appropriate thickness and appropriate anti-deformation ability can be used in the process of lamination or vacuum curing. Under the temperature and high pressure environment, during the downward pressure of the PVB intermediate film 6 or during the downward pressure of the atmospheric pressure in the vacuum bag, the other end has a non-fixed free shrinkage mode and has suitable deformability (for example, at this time, the edge-sealing film is deformed by a greater force under the support and downward pressure of the PVB intermediate film 6, or the edge-sealing film is deformed by a greater force under the support and atmospheric pressure of the vacuum bag, which allows the controllable deformation of the edge-sealing film to be bonded and cured with the silver paste 5 or the lower base layer 12, thereby preventing the film from producing defects such as wrinkles, without the need for edge bonding and edge sealing through two films above and below), and has a better edge sealing effect.

[0076] The above are only optional embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A PDLC film edge sealing method, characterized in that: include: Half-cut pretreatment: performing half-cut pretreatment on the edges of the PDLC film to form edge-sealing steps (72) of a preset width; wherein the cutting depth is to remove the upper substrate layer (11) of the PDLC film; Edge sealing film cutting: based on the outer contour of the PDLC film, cutting the edge sealing film (4) into an edge sealing film pattern that matches the outer contour of the PDLC film; Film positioning and pre-fixing: the cut edge-sealing film pattern is attached to the edge of the PDLC film, and a roller (8) is used to roll along the pre-fixing area (71) for preheating and compacting; wherein the pre-fixing area (71) is the area between the edge of the protective film (3) and the edge of the upper substrate layer (11); the size of the protective film (3) is smaller than the size of the upper substrate layer (11), and the protective film (3) is removed before the final lamination; when the roller (8) is in operation, the distance from the edge of the upper substrate layer (11) and the edge of the protective film (3) is 0.1 mm to 1 mm; the ratio of the width of the pre-fixing area (71) to the width of the edge-sealing step (72) is (1.01-1.6):1; the operating temperature of the roller (8) is 90-120°C, the rolling speed is 0.5-6 m / min, and the pressure applied to the pre-fixing area (71) is 10-30 N; Lamination and secondary curing: laminating the pretreated PDLC film and the glass substrate via a PVB intermediate film (6) to form a sandwich structure, and then placing the sandwich structure in a first autoclave and performing secondary curing at a preset temperature and a preset pressure; wherein the preset temperature is 125-145° C. and the preset pressure is 0.8-1.1 MPa; or, The pre-treated PDLC film is placed in a vacuum bag (10) and then placed in a second autoclave for initial curing under the negative pressure generated by vacuum extraction and the cooperation of the second autoclave; the cured PDLC film is then laminated with the glass substrate using a PVB intermediate film (6) to form the sandwich structure, and the sandwich structure is placed in the first autoclave for further curing under preset temperature and preset pressure conditions.

2. The PDLC film edge sealing method according to claim 1, wherein: The thickness of the protective film (3) is 20-80 μm.

3. The PDLC film edge sealing method according to claim 1, characterized in that: The width of the pre-fixing area (71) is 2-50 mm, and the width of the edge sealing step (72) is 1-70 mm.

4. The PDLC film edge sealing method according to claim 1, wherein: The edge sealing film (4) comprises a base material layer (41) and an adhesive (42) coated on the surface of the base material layer (41); The material of the substrate layer (41) is selected from one or more of polyethylene terephthalate and polyimide; The semi-curing temperature of the viscose (42) is 90-110°C; The adhesive (42) is selected from epoxy resin adhesive.

5. The PDLC film edge sealing method according to claim 4, characterized in that: The thickness of the substrate layer (41) is 20-95 μm; The thickness of the epoxy resin adhesive layer is 5-80 μm.

6. The PDLC film edge sealing method according to claim 1, characterized in that: The thickness of the edge sealing film (4) is 25-100 μm; The thickness of the PVB intermediate film (6) is 0.38-1.52 mm.

7. The PDLC film edge sealing method according to claim 1, characterized in that: The horizontal distance from the edge of the protective film (3) to the edge of the lower base layer (12) is 5-20 mm.

8. The PDLC film edge sealing method according to claim 1, wherein: When the roller (8) is in operation, the width of the contact surface between the roller (8) and the pre-fixed area (71) is 3-15 mm.

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