A method for detecting ultraviolet resistance of polymer dispersed liquid crystal film

Abstract

The present invention discloses a method for testing the UV resistance of a polymer dispersed liquid crystal film, the method comprising: S101: cutting the polymer dispersed liquid crystal film into N sample films of the same size, setting electrodes on the short side of each of the N sample films, and testing the transmittance, haze, and color difference value of each sample film, wherein N is a positive integer greater than 5; S102: taking at least two of the sample films and placing them in an electric blast drying oven, heating them at 100°C-150°C for 1-24 hours, taking them out, and placing them in a room temperature. The film is placed in an environment with a temperature and humidity of 30-60% for 2 hours, and the transmittance, haze and color difference of each film are tested; S103: at least two more sample films are taken out from the N sample films, and the at least two sample films heated in step S102 and the at least two more sample films not heated in step S102 are placed in a UV aging box respectively; S104: the electrodes of the at least two sample films and the at least two more sample films are connected to a control power supply with an output voltage range of AC24V-220V.

Description

Technical Field

[0001] The present invention relates to a method for detecting the ultraviolet resistance of a liquid crystal film, and more particularly to a method for detecting the ultraviolet resistance of a polymer dispersed liquid crystal film. Background Art

[0002] U.S. Patent No. 4,671,618 discloses a method for producing phase-separated polymer-dispersed liquid crystals (PDLCs). This method can be used to produce polymer-dispersed liquid crystal films (PDLCs), also known as PALC films, collectively referred to as PDLC films. PDLC films consist of a liquid crystal-plastic core layer and two transparent conductive film layers, flanking the core. PDLC films can be used to create a range of derivative products, including switchable glass, magic glass, electro-induced liquid crystal atomized glass, and smart glass. PDLC films and their derivatives are a novel material that can control the transition between transmission and scattering of incident light by switching an applied voltage on and off, thereby switching between a transparent state and a frosted state (frosted glass). These products exhibit dual functions of transparency and concealment, and are finding increasing application. Over long-term use, the liquid crystals in PDLC films and their derivatives are easily damaged by ultraviolet light. Damaged PDLC films can exhibit problems such as poor scattering (semi-transparency) when not powered on, bubbles, yellowing, poor peel strength, debonding, and liquid crystal failure. However, since polymer-dispersed liquid crystal films and their derivatives (such as smart glass) are emerging products, testing their UV resistance is based on the standard for laminated glass and automotive glass, "GB5137.3-2002: Test Methods for Automotive Safety Glass - Part 3: Resistance to Radiation, High Temperature, Humidity, Fire, and Simulated Climate Tests." This method involves forming a 76mm x 300mm sample of the film into a smart glass sample, irradiating it in an irradiation device for 100 hours, and then removing the sample for inspection. While this method can determine the UV resistance of smart glass, it is subject to significant interference from external factors, such as the UV blocking rate of the film and the original glass. Furthermore, since polymer-dispersed liquid crystal films spend the majority of their time in an energized state during actual use, UV rays are more destructive to the film and cannot be detected using this method. However, there is currently no unified, reliable, and stable testing method for the UV resistance of polymer-dispersed liquid crystal films, both domestically and internationally. Therefore, there is a need for a method for testing the UV resistance of polymer-dispersed liquid crystal films. Summary of the Invention

[0003] In view of the above-mentioned defects of the prior art, the present invention provides a method for detecting the UV resistance of polymer dispersed liquid crystal films.

[0004] The technical solution adopted by the present invention to solve the technical problem is to construct a method for detecting the ultraviolet resistance of polymer dispersed liquid crystal films, which comprises:

[0005] S101: Cutting the polymer dispersed liquid crystal film into N sample films of the same size, setting electrodes on the short side of each of the N sample films, and testing the transmittance, haze, and color difference of each sample film, where N is a positive integer greater than 5;

[0006] S102: Take at least two sample films and place them in an electric blast drying oven, heat them at 100°C-150°C for 1-24 hours, take them out, place them in an environment with room temperature and 30-60% humidity for 2 hours, and test the transmittance, haze, and color difference of each film;

[0007] S103: taking out at least two more sample films from the N sample films, and placing the at least two sample films heated in step S102 and the at least two more sample films not heated in step S102 in a UV aging chamber respectively;

[0008] S104: connecting the electrodes of the at least two sample films and the at least two other sample films to a control power supply with an output voltage range of AC24V-220V, keeping the at least two sample films and the at least two other sample films in a powered working state, maintaining the ultraviolet radiation source to uniformly irradiate the at least two sample films and the at least two other sample films, maintaining the surface temperature of all sample films at 45±5°C, and irradiating for 48-100 hours;

[0009] S105: Place the at least two sample films and the at least two other sample films in an environment at room temperature and 30-60% humidity for 2 hours, test the transmittance, haze and color difference values of the at least two sample films and the at least two other sample films, and compare the appearance of the at least two sample films and the at least two other sample films with the retained sample film.

[0010] In the method for testing the UV resistance of polymer dispersed liquid crystal films of the present invention, N=7, and S101 further includes numbering the seven sample films 1-7.

[0011] In the method for testing the UV resistance of polymer dispersed liquid crystal films described in the present invention, the at least two sample films are sample films No. 1-3, the other at least two sample films are sample films No. 4-6, and the bottom sample film is sample film No. 7.

[0012] In the method for testing the UV resistance of polymer dispersed liquid crystal films of the present invention, the length and width of each of the N sample films of the same size are 200 mm and 150 mm respectively.

[0013] In the method for testing the UV resistance of a polymer dispersed liquid crystal film described in the present invention, a rotating device for driving the sample film to rotate is provided in the UV aging chamber in this step. The rotating device drives the at least two sample films and the at least two other sample films to rotate around an ultraviolet radiation source arranged at the axis at a speed of 1 r / min-5 r / min.

[0014] The method for testing the UV resistance of a polymer-dispersed liquid crystal film according to the present invention has the following beneficial effects: When implementing the method for testing the UV resistance of a polymer-dispersed liquid crystal film according to the present invention, the polymer-dispersed liquid crystal film is cut into N sample films of equal size, electrodes are set on the short sides of each of the N sample films, and the transmittance, haze, and color difference of each sample film are tested. At least two of the sample films are placed in an electric blast drying oven, heated at 100°C-150°C for 1-24 hours, removed, and placed in an environment at room temperature and 30-60% humidity for 2 hours, and the transmittance, haze, and color difference of each sample film are tested. At least two other sample films are taken from the N sample films, and the at least two sample films heated in step S102 and the at least two other sample films not heated in step S102 are placed in a UV aging oven. The electrodes of the at least two sample films and the at least two other sample films are connected to a control power supply with an output voltage range of AC24V-220V, and the sample films are kept in a powered working state. The ultraviolet radiation source is kept uniformly irradiating the at least two sample films and the at least two other sample films, and the surface temperature of all sample films is kept at 45±5°C for 48-100 hours. The at least two sample films and the at least two other sample films are placed in an environment with room temperature and a humidity of 30-60% and left to stand for 2 hours. The transmittance, haze and color difference values of the at least two sample films and the at least two other sample films are tested, and the appearance of the at least two sample films and the at least two other sample films is compared with the sample film retained. The present invention adopts a method of ultraviolet irradiation of the polymer dispersed liquid crystal film in the powered state, which can accurately and quickly test the ultraviolet resistance of the polymer dispersed liquid crystal film, obtain reliable results, and has the advantages of simplicity, reliability and good repeatability. The present invention directly conducts ultraviolet aging experiments on polymer dispersed liquid crystal films, which can eliminate other interfering factors and provide a reference basis for the use and storage of polymer dispersed liquid crystal films, so as to take targeted measures to improve the service life of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0016] Figure 1 It is a schematic flow chart of a method for testing the UV resistance of a polymer dispersed liquid crystal film according to the present invention. DETAILED DESCRIPTION

[0017] To make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0018] like Figure 1 As shown, in the first embodiment of the method for testing the UV resistance of the polymer dispersed liquid crystal film of the present invention, the testing method includes:

[0019] S101: Cutting the polymer dispersed liquid crystal film into N sample films of the same size, setting electrodes on the short side of each of the N sample films, and testing the transmittance, haze, and color difference of each sample film, where N is a positive integer greater than 5;

[0020] S102: Take at least two sample films and place them in an electric blast drying oven, heat them at 100°C-150°C for 1-24 hours, take them out, place them in an environment with room temperature and 30-60% humidity for 2 hours, and test the transmittance, haze, and color difference of each film;

[0021] S103: taking out at least two more sample films from the N sample films, and placing the at least two sample films heated in step S102 and the at least two more sample films not heated in step S102 in a UV aging chamber respectively;

[0022] S104: connecting the electrodes of the at least two sample films and the at least two other sample films to a control power supply with an output voltage range of AC24V-220V, keeping the at least two sample films and the at least two other sample films in a powered working state, maintaining the ultraviolet radiation source to uniformly irradiate the at least two sample films and the at least two other sample films, maintaining the surface temperature of all sample films at 45±5°C, and irradiating for 48-100 hours;

[0023] S105: Place the at least two sample films and the at least two other sample films in an environment at room temperature and 30-60% humidity for 2 hours, test the transmittance, haze and color difference values of the at least two sample films and the at least two other sample films, and compare the appearance of the at least two sample films and the at least two other sample films with the retained sample film.

[0024] When implementing the method for testing the UV resistance of the polymer dispersed liquid crystal film of the present invention, the polymer dispersed liquid crystal film is cut into N sample films of the same size, electrodes are set on the short sides of each sample film in the N sample films, and the transmittance, haze, and color difference of each sample film are tested. At least two of the sample films are placed in an electric blast drying oven, heated at 100°C-150°C for 1-24 hours, taken out, placed in an environment with room temperature and 30-60% humidity for 2 hours, and the transmittance, haze, and color difference of each film are tested. At least two other sample films are taken out from the N sample films, and the at least two sample films heated in step S102 and the at least two other sample films not heated in step S102 are placed in a UV aging oven respectively. The electrodes of the at least two sample films and the at least two other sample films are connected to a control power supply with an output voltage range of AC24V-220V, and the at least two sample films and the at least two other sample films are kept in a powered working state. The ultraviolet radiation source is kept uniformly irradiating the at least two sample films and the at least two other sample films, and the surface temperature of all sample films is kept at 45±5°C for 48-100 hours. The at least two sample films and the at least two other sample films are placed in an environment with room temperature and a humidity of 30-60% and left to stand for 2 hours. The transmittance, haze and color difference values of the at least two sample films and the at least two other sample films are tested, and the appearance of the at least two sample films and the at least two other sample films is compared with the sample film retained. The present invention adopts the method of ultraviolet irradiation of the polymer dispersed liquid crystal film in the powered state, which can accurately and quickly test the ultraviolet resistance of the polymer dispersed liquid crystal film, obtain reliable results, and has the advantages of simplicity, reliability and good repeatability. The present invention directly conducts ultraviolet aging experiments on polymer dispersed liquid crystal films, which can eliminate other interfering factors and provide a reference basis for the use and storage of polymer dispersed liquid crystal films, so as to take targeted measures to improve the service life of the product.

[0025] Preferably, N=7, and S101 further includes numbering the seven sample films 1 to 7. The at least two sample films are sample films No. 1 to 3, the other at least two sample films are sample films No. 4 to 6, and the bottom sample film is sample film No. 7.

[0026] In this embodiment, preferably, the length and width of each of the N sample films of the same size are 200 mm and 150 mm respectively.

[0027] In other embodiments, the length and width of the sample film are not fixed, as long as they can be placed in the UV aging box.

[0028] In order to achieve a better uniform irradiation effect, a rotating device is provided in the UV aging box in this step to drive the sample film to rotate. The rotating device drives the at least two sample films and the at least two other sample films to rotate around the UV radiation source set at the axis at a speed of 1 r / min-5 r / min.

[0029] Preferably, due to the problem of electrode wire winding, the rotating device can be set to forward and reverse rotation, and rotate forward M times and then reverse N times, such as forward rotation 50 times, then reverse rotation 100 times, and then forward rotation 100 times, and so on.

[0030] Furthermore, in the present invention, unless otherwise expressly specified or limited, terms such as "connected," "connected," and "stacked" should be interpreted broadly. For example, they may refer to fixed or detachable connections, or integration; they may refer to direct connection or indirect connection through an intermediate medium; they may refer to internal communication between two elements or interaction between two elements. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0031] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention's description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for detecting the UV resistance of a polymer dispersed liquid crystal film, characterized in that: The detection method comprises: S101: Cutting the polymer dispersed liquid crystal film into 7 sample films of the same size, the 7 sample films are numbered 1-7, setting electrodes on the short side of each of the 7 sample films, and testing the transmittance, haze, and color difference of each sample film; S102: Take sample films No. 1-3 and place them in an electric blast drying oven, heat them at 100°C-150°C for 1-24 hours, take them out, place them in an environment with room temperature and 30-60% humidity for 2 hours, and test the transmittance, haze, and color difference of each piece; S103: placing the sample films No. 1-3 heated in step S102 and the sample films No. 4-6 not heated in step S102 in a UV aging chamber respectively; S104: Connecting the electrodes of the sample films No. 1-3 and the sample films No. 4-6 to a control power supply with an output voltage range of AC24V-220V, keeping the sample films No. 1-3 and the sample films No. 4-6 in a powered working state, maintaining the ultraviolet radiation source to uniformly irradiate the sample films No. 1-3 and the sample films No. 4-6, maintaining the surface temperature of all sample films at 45±5°C, and irradiating for 48-100 hours; S105: Place the sample films No. 1-3 and the sample films No. 4-6 in an environment at room temperature and humidity of 30-60% and let them stand for 2 hours, test the transmittance, haze and color difference values of the sample films No. 1-3 and the sample films No. 4-6, and compare the appearance of the sample films No. 1-3 and the sample films No. 4-6 with the bottom sample film, and the bottom sample film is sample film No.

7.

2. The method for detecting the UV resistance of polymer dispersed liquid crystal film according to claim 1, wherein: The length and width of each of the seven sample films of the same size are 200 mm and 150 mm, respectively.

3. The method for detecting the UV resistance of polymer dispersed liquid crystal film according to claim 1, wherein: The UV aging box is provided with a rotating device for driving the sample films to rotate, and the rotating device drives the sample films No. 1-3 and the sample films No. 4-6 to rotate around the UV radiation source set at the axis at a speed of 1 r / min-5 r / min.

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