Infrared high-transmission retroreflective film and method of making same

Abstract

The present application relates to a kind of infrared high-transmittance retroreflective film and its preparation method, belong to unsaturated polyester technical field.It is bonded by infrared high-transmittance film and retroreflective film, wherein, infrared high-transmittance film includes by weight: modified polyester resin 100 parts, visible light cut-off agent 1.8-2.4 parts, lubricant 1.2-1.5 parts and antistatic agent 0.15-0.2 parts;Modified polyester resin is made into compound with alcohol amine structure by dihydric alcohol diglycidyl ether and 2,2-difluoroethylamine ring opening, i.e. modified monomer, again by modified monomer and ethylene glycol with terephthalic acid coesterification condensation, form modified monomer block polyester resin;During the process of blending film, modified polyester resin and metal phthalocyanine derivative synergistic effect, improve the dispersibility of metal phthalocyanine derivative, reduce the scattering of light wave in film layer, improve the transmittance of infrared light and reduce retro attenuation rate, conducive to improve the stability of optoelectronic system.

Description

Technical Field

[0001] This invention belongs to the field of unsaturated polyester technology, specifically relating to an infrared high-transmittance retroreflective film and its preparation method. Background Technology

[0002] Traditional capacitive touchscreens rely on sensing changes in capacitance to recognize touches, which has limitations such as low sensitivity, susceptibility to interference, and difficulty in adapting well to environmental conditions such as fog and rain. In contrast, optical touchscreens use active optical sensors to scan the touchscreen surface and locate fingers by recognizing changes in the reflected light at the touch point. They have advantages such as high sensitivity, good anti-interference, and environmental adaptability, and are widely used in electronic devices such as smartphones, tablets, and laptops.

[0003] Retroreflective films, as a key component, play a crucial role in the working principle of touchscreens. In optical touchscreens, a set of light sources and sensors typically detect the touch position. Retroreflective films reflect light waves, recognizing the touch position by sensing the displacement of an object on the reflected light waves. Infrared light is invisible to the human eye, therefore it does not interfere with the user's visual experience. This means that users do not see the light source when operating the touchscreen, providing a cleaner and more professional display effect. However, existing retroreflective films are susceptible to interference from visible light during infrared light emission, resulting in lower touch accuracy. Summary of the Invention

[0004] In order to solve the technical problems mentioned in the background art, the purpose of this invention is to provide an infrared high-transmittance retroreflective film and its preparation method.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] An infrared high-transmittance retroreflective film, belonging to the field of unsaturated polyester technology, is formed by bonding an infrared high-transmittance film and a retroreflective film. The infrared high-transmittance film, by weight, comprises: 100 parts modified polyester resin, 1.8-2.4 parts visible light cutoff agent, 1.2-1.5 parts lubricant, and 0.15-0.2 parts antistatic agent. The preparation method of the infrared high-transmittance film is as follows: premixing the modified polyester resin, visible light cutoff agent, lubricant, and antistatic agent, plasticizing and extruding at 280±5℃, calendering and cooling to obtain the infrared high-transmittance film.

[0007] Furthermore, the visible light cutoff agent is a metal phthalocyanine derivative, which has good visible light cutoff and infrared transmission properties, and has good compatibility with modified polyester resin.

[0008] Furthermore, the thickness of the infrared high-transmittance film is 100-150μm, which has good cutoff for visible light within this thickness range, while having little impact on the transmission of infrared light.

[0009] The preparation method of the infrared high-transmittance retroreflective film is as follows: the retroreflective film is unrolled and laid flat, optical adhesive is coated on the surface, the infrared high-transmittance film is attached, and it is naturally cured for 24 hours to obtain the infrared high-transmittance retroreflective film.

[0010] The modified polyester resin was prepared by the following method:

[0011] Step A1: Mix diol diglycidyl ether, aluminum trichloride and anhydrous tetrahydrofuran, purge with dry nitrogen for protection, heat to 40-55℃, slowly add 2,2-difluoroethylamine and stir for 4-6 hours. After the reaction is complete, remove the tetrahydrofuran by rotary evaporation to obtain the modified monomer.

[0012] Furthermore, the diol diglycidyl ether is one of ethylene glycol diglycidyl ether and hexanediol diglycidyl ether.

[0013] Furthermore, the feed ratio of diol diglycidyl ether, 2,2-difluoroethylamine, aluminum trichloride, and anhydrous tetrahydrofuran is 0.1 mol: 0.105-0.11 mol: 20-30 mg: 40-60 mL. Under the promotion of aluminum trichloride, 2,2-difluoroethylamine and diol diglycidyl ether undergo ring-opening to form an alkanolamine compound.

[0014] Step A2: Terephthalic acid, ethylene glycol, and modified monomers are premixed as composite monomers, and antimony trioxide is added and mixed. Under nitrogen protection, the mixture is heated to 190-220℃ for esterification reaction for 2.8-3.5 hours. Then, tetrabutyl titanate is added and mixed, the temperature is raised to 265-280℃, the pressure is reduced to 1 kPa, and polycondensation is carried out for 6.2-7.5 hours. The mixture is then discharged and cooled to obtain modified polyester resin.

[0015] Furthermore, the alkyd ratio in the composite monomer is 1.2-1.4, the molar ratio of ethylene glycol to modified monomer is 1:0.12-0.18; the amount of antimony trioxide is 0.06-0.08 wt% of the composite monomer, and the amount of tetrabutyl titanate is 0.02-0.03 wt% of the composite monomer; the modified monomer and ethylene glycol are coesterified and condensed with terephthalic acid to form a polyester resin with modified monomer blocks.

[0016] The beneficial effects of this invention are:

[0017] This invention, based on existing diamond-grade retroreflective films, endows composite films with excellent visible light cutoff and high infrared light transmittance through a composite infrared high-transmittance film. This infrared high-transmittance film uses a self-developed modified polyester resin as the film-forming agent and a metal phthalocyanine derivative as the visible light cutoff agent. The modified polyester resin is prepared by ring-opening diol diglycidyl ether with 2,2-difluoroethylamine to form a compound with an alkanolamine structure, i.e., a modified monomer. This modified monomer is then co-esterified and condensed with ethylene glycol and terephthalic acid to form a modified monomer block polyester resin. During the blending process, the amine structure introduced by the modified agent block forms hydrogen bonds with the nitrogen in the metal phthalocyanine derivative, improving the dispersibility of the metal phthalocyanine derivative during blending and enhancing its ability to block visible light. The complete absorption and cutoff of visible light reduces interference from visible light during retroreflection, which is of great significance for reducing the retroreflection attenuation rate. Thanks to hydrogen bonding, the fluorinated ether structure is attached to the surface of the metal phthalocyanine derivative particles. On the one hand, it modifies the surface of the metal phthalocyanine derivative, reduces its surface defects, makes the surface smoother, and reduces infrared light scattering. On the other hand, the fluorine doping reduces the refractive index of the polymer material on the surface of the metal phthalocyanine derivative, reduces the degree of diffuse reflection, and thus reduces the transmittance of infrared light. In the test, the infrared high transmittance film has a high cutoff in the visible light band, high transmittance in the infrared band, and a lower retroreflection attenuation rate in the composite film, which is beneficial to improving the stability of the optoelectronic system. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 The transmittance curves of the infrared high-transmittance film of the present invention are shown in the wavelength range of 400-940nm. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1: Preparation of an infrared high-transmittance retroreflective film, as detailed below:

[0022] (1) Preparation of infrared high-transmittance membrane

[0023] Step A1: Mix ethylene glycol diglycidyl ether, aluminum trichloride, and anhydrous tetrahydrofuran, purge with dry nitrogen for protection, heat to 40°C, and slowly add 2,2-difluoroethylamine while stirring at 120 rpm for 6 hours. The feed ratio of ethylene glycol diglycidyl ether, 2,2-difluoroethylamine, aluminum trichloride, and anhydrous tetrahydrofuran is 0.1 mol: 0.105 mol: 20 mg: 40 mL. After the reaction is complete, remove the tetrahydrofuran by rotary evaporation to obtain the modified monomer.

[0024] Step A2: Take terephthalic acid, ethylene glycol, and modified monomer premix as composite monomers, add antimony trioxide and feed them together. Under nitrogen protection, heat to 190℃ and esterify for 3.5h. Then add tetrabutyl titanate and mix. Heat to 265℃, reduce pressure to 1kPa, and polycondense for 7.5h. The alcohol-acid ratio in the composite monomer is 1.4, the molar ratio of ethylene glycol to modified monomer is 1:0.12, the amount of antimony trioxide is 0.08wt% of the composite monomer, and the amount of tetrabutyl titanate is 0.02wt% of the composite monomer. Discharge and cool to obtain modified polyester resin.

[0025] According to the weight proportions, 100 parts of modified polyester resin were prepared in-house; 1.8 parts of visible light blocking agent were selected from copper phthalocyanine from Xi'an Qiyue Biotechnology Co., Ltd.; 1.2 parts of lubricant were selected from KJ-B01 type silicone powder from Hangzhou Kaijie Plastics Technology Co., Ltd.; and 0.2 parts of antistatic agent were selected from LQX-30 type antistatic agent from Shenzhen Hongtai Xuanyou New Materials Co., Ltd.

[0026] The above raw materials are premixed, plasticized and extruded at 280±5℃, calendered and cooled to produce a film material with a thickness of 120μm, thus obtaining an infrared high-transmittance film.

[0027] (2) Preparation of infrared high transmittance retroreflective film

[0028] 3M's 4090T diamond-grade film and retroreflective film were selected, unrolled and laid flat, and EPO-TEK® 301-1 optical adhesive was applied to the surface, with the adhesive application amount controlled at 100±5g / m². 2 An infrared high-transmittance film is attached and allowed to cure naturally for 24 hours to obtain an infrared high-transmittance retroreflective film.

[0029] Example 2: Preparation of an infrared high-transmittance retroreflective film, as detailed below:

[0030] (1) Preparation of infrared high-transmittance membrane

[0031] Step A1: Mix ethylene glycol diglycidyl ether, aluminum trichloride, and anhydrous tetrahydrofuran, purge with dry nitrogen for protection, heat to 45°C, and slowly add 2,2-difluoroethylamine while stirring at 150 rpm for 5.5 h. The feed ratio of ethylene glycol diglycidyl ether, 2,2-difluoroethylamine, aluminum trichloride, and anhydrous tetrahydrofuran is 0.1 mol: 0.105 mol: 22 mg: 45 mL. After the reaction is complete, remove the tetrahydrofuran by rotary evaporation to obtain the modified monomer.

[0032] Step A2: Take terephthalic acid, ethylene glycol, and modified monomer premix as composite monomers, add antimony trioxide and feed them together. Under nitrogen protection, heat to 200℃ and esterify for 3.2h. Then add tetrabutyl titanate and mix. Heat to 270℃, reduce pressure to 1kPa, and polycondense for 7h. The alcohol-acid ratio in the composite monomer is 1.3, the molar ratio of ethylene glycol to modified monomer is 1:0.15, the amount of antimony trioxide is 0.07wt% of the composite monomer, and the amount of tetrabutyl titanate is 0.02wt% of the composite monomer. Discharge and cool to obtain modified polyester resin.

[0033] According to the weight proportions, 100 parts of modified polyester resin were prepared in-house; 2.2 parts of visible light blocking agent were selected from copper phthalocyanine from Xi'an Qiyue Biotechnology Co., Ltd.; 1.5 parts of lubricant were selected from KJ-B01 type silicone powder from Hangzhou Kaijie Plastics Technology Co., Ltd.; and 0.18 parts of antistatic agent were selected from LQX-30 type antistatic agent from Shenzhen Hongtai Xuanyou New Materials Co., Ltd.

[0034] The above raw materials are premixed, plasticized and extruded at 280±5℃, calendered and cooled to produce a film material with a thickness of 120μm, thus obtaining an infrared high-transmittance film.

[0035] (2) Preparation of infrared high transmittance retroreflective film

[0036] 3M's 4090T diamond-grade film and retroreflective film were selected, unrolled and laid flat, and EPO-TEK® 301-1 optical adhesive was applied to the surface, with the adhesive application amount controlled at 100±5g / m². 2 An infrared high-transmittance film is attached and allowed to cure naturally for 24 hours to obtain an infrared high-transmittance retroreflective film.

[0037] Example 3: Preparation of an infrared high-transmittance retroreflective film, as detailed below:

[0038] (1) Preparation of infrared high-transmittance membrane

[0039] Step A1: Mix hexanediol diglycidyl ether, aluminum trichloride, and anhydrous tetrahydrofuran, purge with dry nitrogen for protection, heat to 55°C, and slowly add 2,2-difluoroethylamine while stirring at 180 rpm for 4 hours. The feed ratio of hexanediol diglycidyl ether, 2,2-difluoroethylamine, aluminum trichloride, and anhydrous tetrahydrofuran is 0.1 mol: 0.11 mol: 30 mg: 60 mL. After the reaction is complete, remove the tetrahydrofuran by rotary evaporation to obtain the modified monomer.

[0040] Step A2: Take terephthalic acid, ethylene glycol, and modified monomer premix as composite monomers, add antimony trioxide and feed them together. Under nitrogen protection, heat to 220℃ and esterify for 2.8h. Then add tetrabutyl titanate and mix. Heat to 280℃, reduce pressure to 1kPa, and polycondense for 6.2h. The alcohol-acid ratio in the composite monomer is 1.2, the molar ratio of ethylene glycol to modified monomer is 1:0.18, the amount of antimony trioxide is 0.06wt% of the composite monomer, and the amount of tetrabutyl titanate is 0.03wt% of the composite monomer. After cooling, the modified polyester resin is obtained.

[0041] According to the weight proportions, 100 parts of modified polyester resin were prepared in-house; 2.4 parts of visible light blocking agent were selected from copper phthalocyanine from Xi'an Qiyue Biotechnology Co., Ltd.; 1.4 parts of lubricant were selected from KJ-B01 type silicone powder from Hangzhou Kaijie Plastics Technology Co., Ltd.; and 0.15 parts of antistatic agent were selected from LQX-30 type antistatic agent from Shenzhen Hongtai Xuanyou New Materials Co., Ltd.

[0042] The above raw materials are premixed, plasticized and extruded at 280±5℃, calendered and cooled to produce a film material with a thickness of 120μm, thus obtaining an infrared high-transmittance film.

[0043] (2) Preparation of infrared high transmittance retroreflective film

[0044] 3M's 4090T diamond-grade film and retroreflective film were selected, unrolled and laid flat, and EPO-TEK® 301-1 optical adhesive was applied to the surface, with the adhesive application amount controlled at 100±5g / m². 2 An infrared high-transmittance film is attached and allowed to cure naturally for 24 hours to obtain an infrared high-transmittance retroreflective film.

[0045] Example 4: Preparation of an infrared high-transmittance retroreflective film, as detailed below:

[0046] (1) Preparation of infrared high-transmittance membrane

[0047] Step A1: Mix hexanediol diglycidyl ether, aluminum trichloride, and anhydrous tetrahydrofuran, purge with dry nitrogen for protection, heat to 50°C, and slowly add 2,2-difluoroethylamine while stirring at 180 rpm for 4.5 h. The feed ratio of hexanediol diglycidyl ether, 2,2-difluoroethylamine, aluminum trichloride, and anhydrous tetrahydrofuran is 0.1 mol: 0.108 mol: 26 mg: 55 mL. After the reaction is complete, remove the tetrahydrofuran by rotary evaporation to obtain the modified monomer.

[0048] Step A2: Take terephthalic acid, ethylene glycol, and modified monomer premix as composite monomers, add antimony trioxide and feed them together. Under nitrogen protection, heat to 210℃ for esterification reaction for 3 hours. Then add tetrabutyl titanate and mix. Heat to 275℃, reduce pressure to 1 kPa, and polycondense for 6.5 hours. The alcohol-acid ratio in the composite monomer is 1.3, the molar ratio of ethylene glycol to modified monomer is 1:0.16, the amount of antimony trioxide is 0.07 wt% of the composite monomer, and the amount of tetrabutyl titanate is 0.03 wt% of the composite monomer. Discharge and cool to obtain modified polyester resin.

[0049] According to the weight proportions, 100 parts of modified polyester resin were prepared in-house; 2 parts of visible light blocking agent were selected from copper phthalocyanine from Xi'an Qiyue Biotechnology Co., Ltd.; 1.3 parts of lubricant were selected from KJ-B01 type silicone powder from Hangzhou Kaijie Plastics Technology Co., Ltd.; and 0.17 parts of antistatic agent were selected from LQX-30 type antistatic agent from Shenzhen Hongtai Xuanyou New Materials Co., Ltd.

[0050] The above raw materials are premixed, plasticized and extruded at 280±5℃, calendered and cooled to produce a film material with a thickness of 120μm, thus obtaining an infrared high-transmittance film.

[0051] (2) Preparation of infrared high transmittance retroreflective film

[0052] 3M's 4090T diamond-grade film and retroreflective film were selected, unrolled and laid flat, and EPO-TEK® 301-1 optical adhesive was applied to the surface, with the adhesive application amount controlled at 100±5g / m². 2 An infrared high-transmittance film is attached and allowed to cure naturally for 24 hours to obtain an infrared high-transmittance retroreflective film.

[0053] Comparative Example 1, referring to Example 4, involved replacing the modifying monomer with ethylene glycol in equal molar amounts during the synthesis of the modified polyester resin, while the rest of the process remained exactly the same.

[0054] Comparative Example 2 uses the polyester resin prepared in Comparative Example 1, and replaces the copper phthalocyanine in this case with an equal amount of BZH type visible light cutoff agent from Shanghai Yuansu Chemical Technology Co., Ltd., while the rest of the implementation process is exactly the same.

[0055] Samples were taken from the infrared high-transmittance film prepared above, and the light transmittance in the 400-940nm wavelength band was measured according to GB / T 36403-2018 standard, specifically as follows: Figure 1 As shown;

[0056] Depend on Figure 1 It can be seen that the infrared high-transmittance film prepared in the examples has a high cutoff for the visible light band and a high transmittance for the infrared light band. Compared with Comparative Example 1, the cutoff for visible light is higher and the transmittance for infrared light is even higher. Compared with Comparative Example 2, Comparative Example 2 has a higher cutoff for light in the band below 700nm and a lower transmittance for nitrogen infrared light.

[0057] Samples were taken from the infrared high-transmittance retroreflective film prepared above, and the reflectance at wavelengths of 850 nm and 940 nm was measured using a spectrophotometer. Using the 0° retroreflectance ρ0 as a reference, the 45° retroreflectance ρ1 was measured, and the retroreflection attenuation rate Δρ = (ρ0 - ρ1) / ρ0 × 100% was calculated, as shown in Table 1.

[0058] As shown in Table 1, the infrared high-transmittance retroreflective film prepared in the example has a higher 0° retroreflectivity, and the retroreflection attenuation rate is lower than that of the comparative example at wavelengths of 850nm and 940nm. This results in lower large-angle attenuation of the retroreflective system, which is beneficial to improving the stability of the optoelectronic system.

[0059] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0060] The above description is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the concept of the invention or exceed the scope defined in the claims, they should all fall within the protection scope of the present invention.

Claims

1. An infrared high-transmittance retroreflective film, comprising an infrared high-transmittance film and a retroreflective film bonded together, characterized in that, The infrared high-transmittance film comprises, by weight: 100 parts modified polyester resin, 1.8-2.4 parts visible light cutoff agent, 1.2-1.5 parts lubricant, and 0.15-0.2 parts antistatic agent; The visible light blocking agent is a metal phthalocyanine derivative; The modified polyester resin is prepared by the following method: Step A1: Mix diol diglycidyl ether, aluminum trichloride and anhydrous tetrahydrofuran, purge with dry nitrogen for protection, heat to 40-55℃, slowly add 2,2-difluoroethylamine and stir for 4-6 hours. After the reaction is complete, remove the tetrahydrofuran by rotary evaporation to obtain the modified monomer. Step A2: Terephthalic acid, ethylene glycol, and modified monomers are premixed as composite monomers, and antimony trioxide is added and mixed. Under nitrogen protection, the mixture is heated to 190-220℃ for esterification reaction for 2.8-3.5 hours. Then, tetrabutyl titanate is added and mixed, the temperature is raised to 265-280℃, the pressure is reduced to 1 kPa, and polycondensation is carried out for 6.2-7.5 hours. The mixture is then discharged and cooled to obtain modified polyester resin.

2. The infrared high-transmittance retroreflective film according to claim 1, characterized in that, Diol diglycidyl ether is one of ethylene glycol diglycidyl ether and hexanediol diglycidyl ether.

3. The infrared high-transmittance retroreflective film according to claim 2, characterized in that, The feed ratio of diglycidyl diol ether, 2,2-difluoroethylamine, aluminum trichloride and anhydrous tetrahydrofuran is 0.1mol:0.105-0.11mol:20-30mg:40-60mL.

4. The infrared high-transmittance retroreflective film according to claim 3, characterized in that, The alcohol-acid ratio in the composite monomer is 1.2-1.4, and the molar ratio of ethylene glycol to modified monomer is 1:0.12-0.18; the amount of antimony trioxide is 0.06-0.08 wt% of the composite monomer, and the amount of tetrabutyl titanate is 0.02-0.03 wt% of the composite monomer.

5. The infrared high-transmittance retroreflective film according to any one of claims 1-4, characterized in that, The preparation method of infrared high transmittance retroreflective film is as follows: modified polyester resin, visible light cut-off agent, lubricant and antistatic agent are premixed, plasticized and extruded at 280±5℃, calendered and cooled to obtain infrared high transmittance film.

6. The infrared high-transmittance retroreflective film according to claim 5, characterized in that, The thickness of the infrared high-transmittance film is 100-150μm.

7. The method for preparing the infrared high-transmittance retroreflective film according to claim 1, characterized in that, Specifically, the process involves unrolling and laying the retroreflective film flat, applying optical adhesive to the surface, attaching an infrared high-transmittance film, and allowing it to cure naturally for 24 hours to obtain an infrared high-transmittance retroreflective film.

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