Method and apparatus for manufacturing smart film

Abstract

The invention relates to a method for manufacturing a smart film device, the method comprising several steps. A first step comprises cutting a first conductive layer of a smart film arrangement (10) such that the cutting divides the first conductive layer into a half-cut portion (40) and a scrap portion (41). Then, a removal roller (5) removes the scrap portion (41) of the first conductive layer from the smart film arrangement (10). Then, a curable polymer (60) is applied along the edges of the half-cut portion (40). Then, a radiation source (7) is applied over the curable polymer (60) to cure the curable polymer (60), thereby forming a cured polymer around the edges of the half-cut portion (40). Finally, a second cutting head (8) cuts a final component, the final component comprising a portion of the smart film arrangement including the half-cut portion and at least a portion of the cured polymer, thereby separating the final component from the remaining portion of the smart film arrangement.

Description

Technical Field

[0001] This invention belongs to the field of smart film technology. More specifically, this invention relates to a rapidly UV-curable polymer for edge sealing of polymer-dispersed liquid crystal (PDLC) smart films, and a method for edge sealing of said films. Background Technology

[0002] Polymer dispersed liquid crystal (PDLC) smart films consist of liquid crystal droplets dispersed in a matrix based on a UV-curable optical polymer. This matrix is ​​coated between two conductive transparent layers (typically polyethylene terephthalate films coated with transparent conductive oxides), effectively forming a capacitor. The capacitor is laminated between two glass sheets via an adhesive interlayer (typically polyvinyl butyral (PVB), thermoplastic polyurethane (TPU), or ethylene-vinyl acetate copolymer (EVA)). By default, the liquid crystal droplets are randomly oriented, scattering light and creating an opaque state. However, when a sufficiently strong voltage is applied, the liquid crystals align along the direction of the electric field, providing a transmission direction for light. Therefore, PDLC glass structures are used as windows or skylights in buildings or vehicles, allowing for selective adjustment of light transmittance.

[0003] Focusing on its automotive applications, most existing light-controlling PDLC glass structures are laminated glass products using PVB as the adhesive interlayer. However, PDLC materials are incompatible with PVB. Their bonding results in a continuously extending transparent boundary line around the PDLC film, meaning a partial loss of its light-controlling function. Therefore, there is a need for a polyPDLC edge-sealing material suitable for automotive applications that not only does not react with PDLC but also does not create wrinkles at curves and corners as is seen when using tape for edge sealing.

[0004] This invention provides a solution to the above-mentioned technical problems through a manufacturing method and a polymer. Summary of the Invention

[0005] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall be interpreted in accordance with their conventional meaning in the field. It should also be understood that commonly used terms shall be interpreted in accordance with their conventional meaning in the relevant field, and should not be construed as having an idealized or overly formal meaning, unless explicitly defined herein.

[0006] In this document, the term “including” and its derivatives (such as “contains”, etc.) should not be understood as having an exclusionary meaning, that is, these terms should not be interpreted as excluding the possibility that the content described and defined may include other elements, steps, etc.

[0007] The first object of the present invention relates to a method for manufacturing a smart film device, the method comprising: unfolding a smart film arrangement from a first roller onto a working surface, the smart film arrangement including a first conductive layer, a second conductive layer, and a cured PDLC material layer located between the first and second conductive layers, such that the smart film arrangement sequentially undergoes the following steps: The first cutting head performs a half-cut, thereby cutting the first conductive layer of the smart thin film arrangement, such that the half-cut divides the first conductive layer into a half-cut portion and a waste portion, wherein the half-cut portion has an edge; The removal roller removes the waste portion of the first conductive layer from the smart film arrangement; Apply a curable polymer along the edge of the hemisection; A radiation source is applied above the curable polymer to cure the curable polymer, thereby forming a cured polymer around the edge of the hemisection; and The second cutting head cuts the final component, which includes a portion of the smart film arrangement comprising a half-cut portion and at least a portion of the cured polymer, thereby separating the final component from the remainder of the smart film arrangement.

[0008] This method seals the final portion with a cured polymer that protects the interior of the smart film portion from external chemical or physical agents. This manufacturing and protection method is novel and can be automated on an assembly line.

[0009] In some specific embodiments, the first and / or second cutting heads include plotter blade cutting heads or laser cutting heads. These plotter blade cutting heads or laser cutting heads are suitable tools for performing partial cuts and can be easily adjusted to cut only the first conductive layer of the smart film arrangement without causing any damage to the remainder of the film arrangement.

[0010] In some specific embodiments, the method further includes, after the step of removing the waste portion of the first conductive layer, a step of flattening the smart film arrangement with a flattening roller, such that the cut portion is flattened on the smart film arrangement.

[0011] During the waste removal step, some cut sections may experience undesirable warping. To correct this improper separation, leveling rollers ensure that all cut sections are completely leveled before subsequent steps.

[0012] By selecting the diameter of the leveling roller and the separation angle of the waste section, PDLC residue adheres to the waste section while the main film remains clean and ready to receive a UV-curable polymer. The automated head then applies the UV-curable polymer, covering a few millimeters on one edge (on the PET side) and a few millimeters on the other edge (on the ITO PET side), with the thickness of the curable polymer ranging from 50 µm to 100 µm, thus preparing it for curing by a radiation source.

[0013] In some specific implementations, the step of applying a radiation source includes using a UV light source that emits UV radiation with wavelengths between 365 nm and 385 nm for a duration between 1 second and 5 seconds.

[0014] UV sources are particularly suitable for obtaining radiation to cure the curable polymer.

[0015] In some specific embodiments, the steps of the method are performed consecutively on adjacent portions of the smart thin film arrangement, and the step of removing waste portions is performed consecutively, because the waste portion corresponding to each half-cut portion is a continuous portion of the first conductive layer.

[0016] The method is performed on a continuous roller such that as a slit is created and the roller advances the smart film arrangement, subsequent slits are created adjacent to the previous one. Therefore, the process is continuous, producing a continuous flow of final components.

[0017] In some specific implementations, the width of the slit portion is between 5 mm and 10 mm.

[0018] In a second aspect, the present invention provides an apparatus suitable for performing the steps of the method according to any one of the preceding claims, the apparatus comprising: First roller; The working surface is arranged to receive material spread out by the first roller; A conveyor roller adapted to cause the forward motion of material spread out by the first roller; A first cutting head is arranged to perform a half-cut in the material spread out by the first roller; A removal roller is arranged downstream of the first cutting head and configured to remove the waste portion of the material spread out by the first roller; A polymer dispenser, arranged downstream of the removal roller, is configured to deposit some polymer material on the material spread by the first roller; A radiation source, arranged downstream of the polymer dispenser, is configured to apply some radiation to the material spread by the first roller; and The second cutting head is positioned downstream of the radiation source and configured to perform the final cut in the material spread by the first roller.

[0019] In another aspect of the invention, the present invention provides a UV-curable polymer for edge-sealing polymer-dispersed liquid crystal (PDLC) films. Advantageously, the polymer comprises: Acrylic oligomers, which are 5-50% w / w of the total weight of the UV-curable polymer; Oxygen inhibitors, which are 5-40% w / w relative to the total weight of the UV-curable polymer; Thiols, which constitute 5-50% w / w of the total weight of the UV-curable polymer; and The photoinitiator is present at a ratio of 1-10% w / w to the total weight of the UV-curable polymer.

[0020] When the surface of a polymer material is exposed to atmospheric oxygen during curing, oxygen reacts with free radicals to form peroxy radicals, which prevents the free radicals from initiating a cross-linking chain reaction. This is why the polymer composition of the present invention includes oxygen inhibitors and thiols. Within the scope of this invention, the term "oxygen inhibitor" (or equivalent expressions such as "oxygen scavenger," "oxygen absorber," "oxygen interceptor," etc.) should be understood as any chemical compound having one or more reactive groups that can bind with oxygen to reduce the formation of peroxy radicals. Furthermore, the term "thiol" should be understood as any organosulfur compound in the form R-SH, where R represents an alkyl or other organic substituent. Thanks to this formulation, the phenomenon known as "oxygen inhibition" is significantly reduced.

[0021] This polymer is suitable for use as a polymeric substance in the method of the first aspect of the invention.

[0022] In some specific implementation schemes, The ratio of acrylate oligomers to the total weight of the UV-curable polymer is 20-40% w / w. The oxygen inhibitor is present at a ratio of 20-40% w / w to the total weight of the UV-curable polymer, and / or The ratio of thiols to the total weight of the UV-curable polymer is 20-40% w / w.

[0023] In some specific embodiments, the acrylate oligomers include aliphatic polyurethane acrylates.

[0024] In some specific implementations, oxygen inhibitors include amine-modified polyether acrylates.

[0025] In some specific implementations, the thiol includes trimethylolpropane triacrylate.

[0026] In some specific embodiments, the photoinitiator comprises a mixture of at least two components, wherein the components are as follows: Bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and 2-hydroxy-2-methylphenylacetone; or Diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide and hydroxycyclohexylphenyl ketone; or Bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and hydroxycyclohexylphenyl ketone; or Diphenyl (2,4,6-trimethylbenzoyl)phosphine oxide and 2-hydroxy-2-methylphenylacetone.

[0027] In some specific embodiments, the proportion of each component of the mixture relative to the total weight of the photoinitiator is 10-90% w / w. Attached Figure Description

[0028] To provide a more complete description and facilitate a better understanding of the invention, a set of accompanying drawings is provided. These drawings form part of this specification and illustrate one embodiment of the invention. This embodiment should not be construed as limiting the scope of the invention, but is merely an example of how the invention can be practiced. The drawings include the following figures: Figure 1 An overall view of an apparatus for performing the manufacturing method according to the present invention is shown; Figure 2 A top view showing a specific step of the manufacturing method according to the present invention is shown; Figure 3 A top view is shown illustrating another specific step of the manufacturing method according to the present invention.

[0029] The following reference numerals are used in these figures: 1 First roller 2 Working surface 3 conveyor rollers 4. Half head 5 Remove rollers 6 polymer dispensers 7UV source 8 Second cutting head 9 leveling rollers 10 Smart Thin Films 40 half-cut portion 41 Waste Section 60 polymer substances Detailed Implementation This document describes exemplary embodiments in sufficient detail to enable those skilled in the art to implement and carry out the systems and methods described herein. It is important to understand that embodiments may be provided in various alternative forms and should not be construed as limited to the embodiments set forth herein.

[0030] Therefore, although the embodiments may be modified in various ways and take various alternative forms, specific embodiments thereof are shown in the accompanying drawings and described in detail below as examples. There is no intention to limit oneself to the specific forms disclosed. Rather, all modifications, equivalents, and alternatives falling within the scope of the appended claims should be covered. In the drawings and detailed description, elements of exemplary embodiments are always indicated by the same reference numerals where appropriate.

[0031] Figure 1 Some steps of a method for manufacturing a smart thin-film device according to the present invention are shown.

[0032] The method is performed by an apparatus comprising the following elements: First roller 1; Working surface 2 is arranged to receive material spread out by the first roller 1; The conveyor roller 3 is adapted to cause the forward movement of the material spread out by the first roller 1; The half-cutting head 4 is arranged to cut in the material spread out by the first roller 1; A removal roller 5 is arranged downstream of the half-cutting head 4 and configured to remove the waste portion of the material spread out by the first roller 1; Leveling roller 9 is arranged downstream of removal roller 5; A polymer dispenser 6 is arranged downstream of the removal roller 5 and configured to deposit some polymer material on the material spread by the first roller 1; UV source 7, which is arranged downstream of polymer dispenser 6 and configured to apply some UV radiation to the material spread by first roller 1; The second cutting head 8 is arranged downstream of the UV source 7 and configured to perform the final cut in the material spread by the first roller 1.

[0033] This device is used in the steps of the method according to the present invention.

[0034] A roll of smart film 10 is wound onto a first roller 1. The method includes: unfolding the smart film 10 from the first roller 1 onto a working surface 2 under the action of a conveyor roller 3. The smart film 10 includes a first conductive layer, a second conductive layer, and a cured polymer-dispersed liquid crystal (PDLC) material layer located between the first conductive layer and the second conductive layer.

[0035] The semi-cutting head 4 (e.g., a laser cutting head or a plotter blade cutting head) cuts the first conductive layer of the smart film 10, such that the cut divides the first conductive layer into a semi-cut portion 40 and a waste portion. This first cut can be performed in the first conductive layer. Figure 2 As observed in the top view, the half-cutting head performs a cut similar to a rectangle with rounded corners. The half-cut portion 40 is the inner part of the rectangle, while the waste portion 41 is the remaining part of the smart film. It can be seen from the figure that the operation of the first cutting head 4 is continuous, thus producing a series of half-cut portions 40, while the waste portion is the continuous portion left when obtaining the half-cut portions 40. This cut by the first cutting head only affects the first conductive layer of the smart film 10, and does not affect the PDLC layer or the second conductive layer of the smart film 10.

[0036] Back Figure 1 Once the first cutting head 4 has performed the cut that produces the half-cut portion, the removal roller 5, located downstream of the first cutting head 4, removes the waste portion when it reaches the removal roller 5. As described above, the waste portion is the part of the first conductive layer of the smart film 10 located outside the cut that produces the half-cut portion. Therefore, it is a continuous element that is extracted by the removal roller 5.

[0037] The next step of the method involves passing the smart film 10 through a leveling roller 9. This leveling roller 9 ensures that each portion of the first conductive layer is completely flattened. The reason for using the leveling roller 9 is that when the smart film 10 passes through the removal roller 5, some edges or corners of the cut portion may be slightly raised along with the waste portion. If the method continues with these raised portions present, the final result will be unacceptable; therefore, it is good practice to ensure that the cut portion 40 is completely flattened before subsequent steps.

[0038] By selecting a leveling roller of appropriate diameter and a separation angle for the waste section, PDLC residue adheres to the waste section while the main film remains clean and ready to receive UV-curable polymers.

[0039] The next step of the method includes applying a curable polymer by a polymer dispenser 6 along the edge of the half-cut portion 40.

[0040] Figure 3 The step is shown in a top view. A polymer dispenser applies polymer material 60 along the edge of the halved portion 40. The polymer contacts the edge of the first conductive layer (because the remainder of the conductive layer has been removed by the removal roller) and also contacts the layer immediately below (i.e., the PDLC layer), as the polymer is intended to form a seal between the first conductive layer and the PDLC layer.

[0041] The automatic head of the polymer dispenser applies a UV-curable polymer, covering a few millimeters on one side of the edge (on the PET side) and a few millimeters on the other side of the edge (on the ITO PET side), with the thickness of the curable polymer ranging from 50 µM to 100 µm, thus preparing it for curing by the radiation source.

[0042] The polymer material includes: Acrylic oligomers, which are 20-40% w / w of the total weight of the UV-curable polymer; Oxygen inhibitors, which are 20-40% w / w relative to the total weight of the UV-curable polymer; Thiols, comprising 20-40% w / w of the total weight of the UV-curable polymer; and The photoinitiator is present at a ratio of 1-10% w / w to the total weight of the UV-curable polymer.

[0043] The next step of the method involves applying ultraviolet (UV) radiation through a UV source 7 (e.g., a UV lamp). This UV source induces a rapid curing process in the polymer material, which solidifies and hardens upon exiting the UV source. In this case, the wavelength of the UV radiation is between 365 nm and 385 nm, and the duration is between 1 second and 5 seconds.

[0044] When the UV-curable polymer of this invention is exposed to such UV wavelengths, the photoinitiator is triggered to release free radical species. These free radical species then react with acrylate oligomers to produce crosslinked polymers. To prevent these free radicals from also reacting with oxygen in the air to form very stable peroxide radicals, thiols and oxygen inhibitors are included in the formulation. In this way, good beneath and surface curing can be achieved more quickly, thus requiring a smaller amount of photoinitiator. In addition to rapid curing, the above formulation also ensures that the polymer has good flexibility and low shrinkage.

[0045] The UV-curable polymer of the present invention comprises an acrylate oligomer in a weight ratio of 5-50% w / w relative to the total weight of the UV-curable polymer. In a preferred embodiment of the invention, the concentration of the acrylate oligomer is between 20% w / w and 40% w / w. In specific embodiments, the concentration of the acrylate oligomer is 20% w / w, 25% w / w, 30% w / w, 35% w / w, or 40% w / w.

[0046] The UV-curable polymer of the present invention includes an oxygen inhibitor at a weight ratio of 20-40% w / w relative to the total weight of the UV-curable polymer. In certain embodiments, the concentration of the oxygen inhibitor is 20% w / w, 25% w / w, 30% w / w, 35% w / w, or 40% w / w.

[0047] The UV-curable polymer of the present invention comprises a thiol in a weight ratio of 20-40% w / w relative to the total weight of the UV-curable polymer. In certain embodiments, the concentration of the thiol is 20% w / w, 25% w / w, 30% w / w, 35% w / w, or 40% w / w.

[0048] The UV-curable polymer of the present invention includes a photoinitiator at a weight ratio of 1-10% w / w relative to the total weight of the UV-curable polymer. In a particular embodiment, the concentration of the photoinitiator relative to the total weight of the UV-curable polymer is 1% w / w, 2% w / w, 3% w / w, 4% w / w, 5% w / w, 6% w / w, 7% w / w, 8% w / w, 9% w / w, or 10% w / w. In another preferred embodiment of the invention, the photoinitiator comprises a mixture of at least two components, wherein the components are as follows: Bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and 2-hydroxy-2-methylphenylacetone; or Diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide and hydroxycyclohexylphenyl ketone; or Bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and hydroxycyclohexylphenyl ketone; or Diphenyl (2,4,6-trimethylbenzoyl)phosphine oxide and 2-hydroxy-2-methylphenylacetone.

[0049] In another preferred embodiment of the invention, the proportion of each component of the mixture to the total weight of the photoinitiator is 10-90% w / w.

[0050] In a particular embodiment of the invention, the UV-curable polymer comprises an acrylate oligomer, an oxygen inhibitor, a thiol, and a photoinitiator, but may include additional components. That is, the sum of the weight percentages of the acrylate oligomer, oxygen inhibitor, thiol, and photoinitiator may be less than 100% of the total weight of the composition. Therefore, those skilled in the art will understand that, in a particular embodiment, the weight percentages of these components (acrylate oligomer, oxygen inhibitor, thiol, and photoinitiator) may be expressed as relative amounts, but the presence of additional components in the composition is not excluded.

[0051] In other specific embodiments of the invention, the UV-curable polymer comprises only acrylate oligomers, oxygen inhibitors, thiols, and photoinitiators, with no additional components in the composition. That is, the sum of the weight percentages of the acrylate oligomers, oxygen inhibitors, thiols, and photoinitiators is 100% of the total weight of the composition.

[0052] Once the polymer material on the cut portion 40 has been cured and hardened, the next step of the method involves the operation of a second cutting head 8 on the smart film 10. This second cutting head 8 (e.g., a laser cutting head) cuts a portion of the smart film 10, affecting the PDLC layer in contact with the polymer material and the second conductive layer. This cut does not contact the first conductive layer of the cut portion 40 because the purpose of the cut is to obtain a final part with a profile slightly larger than the profile of the cut portion 40. Therefore, the final part includes at least a portion of the polymer material applied along the edge of the cut portion.

[0053] Because this cutting affects the PDLC layer and the second conductive layer, the result is the formation of a separate final component, which is separated from the remainder of the smart film 10. As described above, the method is performed on a continuous roller, such that as a half-cut portion is created and the roller advances the smart film arrangement, subsequent half-cut portions are created adjacent to the previous one. Therefore, the process is continuous, producing a continuous flow of final components.

Claims

1. A method for manufacturing a smart film device, the method comprising unfolding a smart film arrangement (10) from a first roller (1) onto a working surface (2), the smart film arrangement (10) comprising a first conductive layer, a second conductive layer, and a cured PDLC material layer located between the first conductive layer and the second conductive layer, such that the smart film arrangement sequentially undergoes the following steps: The first cutting head (4) performs a half cut, thereby cutting the first conductive layer of the smart thin film arrangement (10) such that the half cut divides the first conductive layer into a half-cut portion (40) and a waste portion (41), wherein the half-cut portion (40) has an edge; The removal roller (5) removes the waste portion (41) of the first conductive layer from the smart film arrangement (10); A curable polymer (60) is applied along the edge of the cut portion (40). A radiation source (7) is applied over the curable polymer (60) to cure the curable polymer (60), thereby forming a cured polymer around the edge of the hemisection (40); The second cutting head (8) cuts the final component, which includes the portion of the smart film arrangement containing the half-cut portion and at least a portion of the cured polymer, thereby separating the final component from the remainder of the smart film arrangement.

2. The method according to the preceding claim, wherein, The first cutting head and / or the second cutting head includes a plotter blade cutting head or a laser cutting head.

3. The method according to any one of the preceding claims further includes, after the step of removing the waste portion (41) of the first conductive layer, a step of flattening the smart film arrangement (10) with a flattening roller (9) such that the cut portion is flattened on the smart film arrangement.

4. The method according to any one of the preceding claims, wherein, The step of applying the radiation source includes using a UV light source (8) that emits UV radiation with a wavelength between 365 and 385 nm for a duration between 1 and 5 seconds.

5. The method according to any one of the preceding claims, wherein, The steps of the method are performed continuously on adjacent portions of the smart film arrangement, and the step of removing the waste portion is performed continuously because the waste portion corresponding to each half-cut portion is a continuous portion of the first conductive layer.

6. The method according to any one of the preceding claims, wherein, The curable polymer is an ultraviolet (UV) curable polymer, comprising: - Acrylic oligomers, which are 20-40% w / w relative to the total weight of the UV-curable polymer; - An oxygen inhibitor, which is 20-40% w / w relative to the total weight of the UV-curable polymer; - Thiols, which are present in a proportion of 20-40% w / w relative to the total weight of the UV-curable polymer; and - A photoinitiator, which is 1-10% w / w relative to the total weight of the UV-curable polymer.

7. The method according to claim 6, wherein, The acrylate oligomers include aliphatic polyurethane acrylates.

8. The method according to claim 6 or 7, wherein, The oxygen inhibitor includes amine-modified polyether acrylate.

9. The method according to any one of claims 6 to 8, wherein, The thiols include trimethylolpropane triacrylate.

10. The method according to any one of claims 6 to 9, wherein, The photoinitiator comprises a mixture of at least two components, wherein the components are as follows: Bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and 2-hydroxy-2-methylphenylacetone; or Diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide and hydroxycyclohexylphenyl ketone; or Bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and hydroxycyclohexylphenyl ketone; or Diphenyl (2,4,6-trimethylbenzoyl)phosphine oxide and 2-hydroxy-2-methylphenylacetone.

11. The method of claim 10, wherein, The proportion of each component of the mixture relative to the total weight of the photoinitiator is 10-90% w / w.

12. An apparatus suitable for performing the steps of the method according to any one of the preceding claims, the apparatus comprising: First roller (1); The working surface (2) is arranged to receive the material spread out by the first roller (1); The conveying roller (3) is adapted to cause the material spread by the first roller (1) to move forward; A first cutting head (4) is arranged to perform a half-cut in the material spread by the first roller (1); A removal roller (5) is arranged downstream of the first cutting head (4) and configured to remove the waste portion (41) of the material spread out by the first roller (1). A polymer dispenser (6) is arranged downstream of the removal roller and configured to deposit some polymer material (60) on the material spread by the first roller (1). A radiation source (7) is arranged downstream of the polymer dispenser and configured to apply some radiation to the material spread by the first roller; A second cutting head (8) is arranged downstream of the radiation source and configured to perform a final cut in the material spread by the first roller.

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