A high-viscosity infrared absorbing layer, a removable infrared absorbing protective film and its preparation method

Abstract

This invention discloses a high-viscosity infrared absorbing layer, a removable infrared absorbing protective film, and their preparation method. The invention polymerizes an infrared absorber with active groups such as carbon-carbon double bonds onto the main chain structure of acrylate via in-situ polymerization, improving the dispersibility and binding of the infrared absorber in the high-viscosity polyacrylate adhesive. This increases the infrared absorption capacity while reducing the risk of infrared absorber leaching and extending its service life. The infrared absorbing protective film consists of a substrate layer 1, a high-viscosity infrared absorbing layer, a substrate layer 2, a low-viscosity adhesive layer, and a release layer, stacked sequentially. By creating an infrared absorbing interlayer structure, the high-viscosity infrared absorbing layer is isolated from the infrared camera, effectively avoiding the problem of infrared absorber leaching and contaminating the camera due to direct addition of the infrared absorber to the adhesive layer. Simultaneously, the low-viscosity adhesive layer allows for easy removal after use, leaving no residual adhesive or ghosting on the lens surface.

Description

Technical Field

[0001] This invention relates to the field of polymer materials, specifically to a high-viscosity infrared absorbing layer, a removable infrared absorbing protective film, and a method for preparing the same. Background Technology

[0002] In modern society, facial recognition has rapidly emerged as a core technology in biometric identification, widely used not only for identity verification in electronic products but also playing an increasingly important role in public safety, financial payments, and intelligent transportation. However, technological advancements always bring new challenges. In early facial recognition systems, visible light cameras frequently suffered from false recognition due to their high sensitivity to ambient light, especially in low-light or backlight conditions. Near-infrared technology, as a solution, not only achieves accurate recognition in low-light or even no-light environments but also provides a valuable supplement to traditional visible light cameras, particularly in complex environments. However, this technology brings new manufacturing and quality control challenges. To ensure the high performance of infrared cameras, they require rigorous testing and debugging during the manufacturing stage, during which the influence of near-infrared light must be shielded. Against this backdrop, process protection film technology has emerged. An ideal process protection film not only needs high-efficiency infrared shielding performance but also suitable transparency in the visible light range to ensure that manufacturing personnel can observe the appearance of the infrared camera. More importantly, this process protection film needs to be easily peeled off after use without leaving any residue to ensure the camera's clarity and longevity. In addition, the precipitation of infrared absorbers from the protective film during manufacturing is also a problem that cannot be ignored. Once infrared absorbers precipitate, they may contaminate the lens, thereby affecting image quality or causing potential damage to the camera.

[0003] Currently available process protective films often only focus on infrared shielding or physical protection, lacking effective solutions for adhesive residue and infrared absorber leaching contamination after removal. Therefore, designing and developing a removable, residue-free, and non-contaminating multifunctional infrared absorbing protective film has become an urgent industry need. Summary of the Invention

[0004] The purpose of this invention is to provide a high-viscosity infrared absorption layer, a removable infrared absorption protective film, and a method for preparing the same, so as to solve the problems mentioned in the background art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0006] A high-viscosity infrared absorbing layer comprises an infrared absorber chemically modified acrylate polymer, a tackifying resin, and a curing agent. The infrared absorber chemically modified acrylate polymer is obtained by free radical copolymerization of an infrared absorber modified with an acrylamide-containing silane coupling agent and an acrylate monomer.

[0007] Furthermore, the raw materials for preparing the infrared absorber chemically modified acrylate polymer include, by weight, 5-30 parts of infrared absorber, 0.2-1 parts of silane coupling agent containing acrylamide groups, 60-90 parts of soft monomer, 5-30 parts of hard monomer, 0.1-5 parts of functional monomer, 0.1-2 parts of initiator, and 100-160 parts of solvent.

[0008] Furthermore, the infrared absorber is one or more of indium tin oxide (ITO), antimony tin oxide (ATO), cesium-doped tungsten bronze (CsXWO3), and lanthanum hexaboride (LaB6), and the particle size of the infrared absorber is 20-100 nm.

[0009] Furthermore, the acrylamide-containing silane coupling agent is 3-acryloylaminopropyltrimethoxysilane.

[0010] Furthermore, the soft monomer is one or more of 2-ethylhexyl acrylate, ethyl acrylate, lauryl acrylate, n-octyl methacrylate, and octadecyl methacrylate.

[0011] Furthermore, the hard monomer is one or more of methyl acrylate, methyl methacrylate, vinyl acetate, isobornyl methacrylate, and acrylonitrile.

[0012] Furthermore, the functional monomer is one or more of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, and hydroxybutyl acrylate.

[0013] Furthermore, the initiator is azobisisobutyronitrile and / or azobisisoheptanenitrile.

[0014] Furthermore, the solvent is ethyl acetate and ethanol.

[0015] Furthermore, the mass ratio of the chemically modified acrylate polymer and the curing agent in the high-viscosity infrared absorption layer is 100:(0.1-2).

[0016] Furthermore, the curing agent is an epoxy curing agent and / or a metal salt curing agent.

[0017] This invention also discloses a method for preparing a high-viscosity infrared absorption layer, comprising the following steps:

[0018] S1. Weigh out the infrared absorber and ethanol according to the formula, mix them, and then ultrasonically stir for 20-40 minutes to obtain mixture 1. Add mixture 1 and the formula amount of silane coupling agent containing acrylamide groups to a reaction flask equipped with a stirrer, adjust the pH of the system to weakly acidic, let it stand for 20-40 minutes, then heat it to 45-55℃, react it with stirring for 2-3 hours, cool it to room temperature and centrifuge it, wash it with ethanol 2-3 times, and then dry it at 50-60℃ to obtain the surface-modified infrared absorber.

[0019] S2. Weigh the surface-modified infrared absorber, soft monomer, hard monomer, functional monomer, and solvent prepared in step S1 according to the formula, and mix them evenly to obtain a mixed precursor solution. Under nitrogen protection, add half of the formula mass of the mixed precursor solution to the reactor, heat to 60-70℃, add 1 / 3 of the formula mass of the initiator, and keep the temperature for 2 hours after initiating the reaction. Add the remaining 1 / 2 of the mixed precursor solution dropwise. After the dropwise addition is complete, add another 1 / 3 of the formula mass of the initiator, raise the temperature to 85℃ and keep it for 2 hours. Add the remaining 1 / 3 of the initiator, keep it for 1 hour, cool and discharge to obtain the infrared absorber chemically modified polyacrylate compound.

[0020] S3. Mix the formulated amount of infrared absorber chemically modified polyacrylate compound, tackifying resin and curing agent evenly and apply according to the predetermined thickness requirement to obtain a high-viscosity infrared absorption layer.

[0021] The present invention also discloses a removable infrared absorption protective film, which is composed of a substrate layer 1, a high-viscosity infrared absorption layer, a substrate layer 2, a low-viscosity adhesive layer and a release layer stacked sequentially, wherein the high-viscosity infrared absorption layer is the aforementioned high-viscosity infrared absorption layer, and the thickness of the high-viscosity infrared absorption layer is 6-15μm.

[0022] Furthermore, the removable infrared absorbing protective film has an infrared light transmittance of 12-19% and a visible light transmittance of 55-73%.

[0023] Furthermore, the substrate layer 1 and substrate layer 2 are PET films with a thickness of 10-50 μm.

[0024] Furthermore, the high-viscosity infrared absorption layer has a peel force of 2500-3000 gf / in at room temperature and a peel force of 2800-3300 gf / in after bonding and aging at 65℃ / 90%RH.

[0025] Furthermore, the low-tack adhesive layer is an acrylic pressure-sensitive adhesive, comprising, by weight: 100 parts of low-tack acrylic adhesive and 0.5-3 parts of curing agent.

[0026] Furthermore, the low-tack adhesive layer has a thickness of 10-20 μm, a peel force of 30-70 gf / in at 180°C at room temperature, and a peel force of 40-90 gf / in at 180°C after bonding and aging at 65°C / 90%RH.

[0027] Furthermore, the thickness of the release layer is 20-50 μm.

[0028] This invention also discloses a method for preparing a removable infrared absorbing protective film, comprising the following steps:

[0029] S1. Preparation of the infrared absorption interlayer:

[0030] Weigh out the chemically modified polyacrylate compound, tackifying resin and curing agent according to the formula, stir evenly, and apply to one side of the substrate layer 1 according to the thickness requirements. After heating and curing at 100-120℃, a high-viscosity infrared absorption layer is obtained. The side of the high-viscosity infrared absorption layer without the substrate is attached to the substrate layer 2 to obtain an infrared absorption interlayer.

[0031] S2. Preparation of a removable infrared absorption protective film:

[0032] Weigh the low-tack acrylic adhesive and curing agent according to the formula, mix and stir them, and then apply them evenly to the substrate layer 2 of the infrared absorption interlayer according to the thickness requirements. Heat and cure at 100-120℃ to obtain a low-tack adhesive layer. Then, attach a release film to the side of the low-tack adhesive layer that does not have the substrate layer 2 to obtain a release layer, and finally obtain a removable infrared absorption protective film.

[0033] The present invention also discloses the application of a removable infrared absorbing protective film in the manufacturing process of infrared cameras.

[0034] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0035] (1) The present invention uses a silane coupling agent containing acrylamide groups to chemically modify the infrared absorber, so that the surface of the infrared absorber is modified with active groups such as carbon-carbon double bonds and amino groups. Then, the infrared absorber with active groups such as carbon-carbon double bonds is polymerized into the main chain structure of acrylate by in-situ polymerization to obtain the infrared absorber chemically modified acrylate polymer. This greatly improves the dispersibility and binding of the infrared absorber in high-viscosity polyacrylate adhesives, increases its infrared absorption capacity while reducing the risk of infrared absorber precipitation, and thus extends the service life of the infrared absorption protective film.

[0036] (2) By setting up an infrared absorption interlayer structure, the present invention isolates the high-viscosity infrared absorption layer from the infrared camera, effectively avoiding the problem of infrared absorber being directly added to the adhesive layer and causing the infrared absorber to precipitate and contaminate the camera; at the same time, the adhesive layer uses a low-viscosity acrylic adhesive, so that the protective film can be easily removed after the camera manufacturing process and infrared light wave test, and there is no residual glue ghosting on the lens surface. Attached Figure Description

[0037] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0038] Figure 1 This is a schematic diagram of the structure of a removable infrared absorbing protective film according to the present invention.

[0039] In the figure, 1: substrate layer 1, 2: high-viscosity infrared absorption layer, 3: substrate layer 2, 4: low-viscosity adhesive layer, 5: release layer. Detailed Implementation

[0040] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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.

[0041] The models and purchase channels of the low-viscosity acrylic adhesive and curing agent used in this invention are as follows:

[0042] Low-tack acrylic adhesive: TB-900, Jiangxi Taylai Polymer Materials Co., Ltd.;

[0043] Isocyanate curing agent: TG-1, Jiangxi Taylai Polymer Materials Co., Ltd.;

[0044] Tackifying resin, terpene phenol resin TSR-903L, softening point: 150℃, Guangxi Tengxian Tongxuan Lixin Chemical Co., Ltd.

[0045] All figures in the examples and comparative examples are parts by mass.

[0046] Example 1:

[0047] S1. Preparation of acrylate polymers chemically modified with infrared absorbers:

[0048] (1) Weigh 30 parts of ATO powder with a particle size of 30 nm and 30 parts of ethanol, mix them and stir ultrasonically for 30 min to obtain mixture 1. Add the mixture and 1 part of 3-acryloylaminopropyltrimethoxysilane to a reaction flask with a stirrer, adjust the pH of the system to 4, let it stand for 30 min and then heat it to 50 °C. React under stirring for 2 h, cool to room temperature and centrifuge, wash twice with ethanol, and dry at 55 °C to obtain the surface-modified infrared absorber.

[0049] (2) Weigh 14 parts of the surface-modified infrared absorber prepared in step (1), 85 parts of soft monomer: ethyl acrylate, 24 parts of hard monomer: methyl methacrylate, and 1 part of functional monomer: hydroxyethyl methacrylate. Mix them evenly to obtain a mixed precursor solution. Under nitrogen protection, add 1 / 2 of the mixed precursor solution and 60 parts of ethyl acetate to the reactor, heat to 70°C, add 0.4 parts of azobisisobutyronitrile, and keep warm for 2 hours after initiating the reaction. Drop the remaining 1 / 2 of the mixed precursor solution and 60 parts of ethyl acetate. After the drop is complete, add 0.4 parts of the formulation of azobisisobutyronitrile, heat to 85°C and keep warm for 2 hours. Add another 0.4 parts of azobisisobutyronitrile, keep warm for 1 hour, cool and discharge to obtain the acrylate polymer with infrared absorber chemical modification.

[0050] S2. Preparation of a removable infrared absorption protective film:

[0051] (1) Weigh 100 parts of the acrylate polymer modified with infrared absorber, 5 parts of the tackifying resin and 1 part of the curing agent, mix and stir, and then uniformly coat it on one side of the 36μm PET substrate layer 1. The dry film thickness of the coating is 12μm. Dry it at 110℃ for 3min to obtain a high-viscosity infrared absorption layer. Then attach the side of the high-viscosity infrared absorption layer without the substrate to the 23μm PET substrate layer 2 to obtain an infrared absorption interlayer.

[0052] (2) Weigh 100 parts of low-viscosity acrylic adhesive and 2 parts of isocyanate curing agent, mix and stir, and then coat evenly on the substrate layer 2 of the infrared absorption interlayer. The dry film thickness of the coating is 12μm. Dry at 110℃ for 3min to obtain a low-viscosity adhesive layer. On the side of the low-viscosity adhesive layer without the substrate layer 2, attach a 25μm release film to obtain a release layer, and then obtain a removable infrared absorption protective film.

[0053] Example 2:

[0054] S1. Preparation of acrylate polymers chemically modified with infrared absorbers:

[0055] (1) Weigh 30 parts of ITO powder with a particle size of 80 nm and 30 parts of ethanol, mix them and stir ultrasonically for 30 min to obtain mixture 1. Add the mixture and 1 part of 3-acryloylaminopropyltrimethoxysilane to a reaction flask with a stirrer, adjust the pH of the system to 4, let it stand for 30 min and then heat it to 50 °C. React under stirring for 2 h, cool to room temperature and centrifuge, wash twice with ethanol, and dry at 55 °C to obtain the surface-modified infrared absorber.

[0056] (2) Weigh 26 parts of the surface-modified infrared absorber prepared in step (1), 62 parts of soft monomer: 2-ethylhexyl acrylate, 4 parts of hard monomer: methyl methacrylate, 6 parts of isobornyl methacrylate, and 2 parts of functional monomer: hydroxyethyl acrylate. Mix them evenly to obtain a mixed precursor solution. Under nitrogen protection, add 1 / 2 of the mixed precursor solution and 60 parts of ethyl acetate to the reactor, heat to 70°C, add 0.4 parts of azobisisobutyronitrile, and keep warm for 2 hours after initiating the reaction. Drop the remaining 1 / 2 of the mixed precursor solution and 60 parts of ethyl acetate. After the drop is complete, add 0.4 parts of the formulation of azobisisobutyronitrile, heat to 85°C and keep warm for 2 hours. Add another 0.4 parts of azobisisobutyronitrile, keep warm for 1 hour, cool and discharge to obtain the acrylate polymer with infrared absorber chemical modification.

[0057] S2. Preparation of a removable infrared absorption protective film:

[0058] (1) Weigh 100 parts of the chemically modified acrylate polymer, 5 parts of the tackifying resin and 1.5 parts of the curing agent, mix and stir, and then uniformly coat it on one side of the 36μm PET substrate layer 1. The dry film thickness of the coating is 8μm. Dry it at 110℃ for 3min to obtain a high-viscosity infrared absorption layer. Then attach the side of the high-viscosity infrared absorption layer without the substrate to the 23μm PET substrate layer 2 to obtain an infrared absorption interlayer.

[0059] (2) Weigh 100 parts of low-viscosity acrylic adhesive and 2 parts of isocyanate curing agent, mix and stir, and then coat evenly on the substrate layer 2 of the infrared absorption interlayer. The dry film thickness of the coating is 12μm. Dry at 110℃ for 3min to obtain a low-viscosity adhesive layer. On the side of the low-viscosity adhesive layer without the substrate layer 2, attach a 25μm release film to obtain a release layer, and then obtain a removable infrared absorption protective film.

[0060] Example 3:

[0061] S1. Preparation of acrylate polymers chemically modified with infrared absorbers:

[0062] (1) Weigh 30 parts of CsXWO3 powder with a particle size of 50nm and 30 parts of ethanol, mix them and stir ultrasonically for 30min to obtain mixture 1. Add the mixture and 1 part of 3-acryloylaminopropyltrimethoxysilane to a reaction flask with a stirrer, adjust the pH of the system to 4, let it stand for 30min and then heat it to 50℃, react it with stirring for 2h, cool it to room temperature and centrifuge it, wash it twice with ethanol, and dry it at 55℃ to obtain the surface-modified infrared absorber.

[0063] (2) Weigh 9 parts of the surface-modified infrared absorber prepared in step (1), soft monomers: 30 parts of ethyl acrylate and 42 parts of lauryl acrylate, hard monomers: 8 parts of methyl acrylate and 10 parts of acrylonitrile, functional monomers: 2.5 parts of hydroxypropyl acrylate, mix them evenly to obtain a mixed precursor solution; under nitrogen protection, add 1 / 2 of the mixed precursor solution and 60 parts of ethyl acetate to the reactor, heat to 70°C, add 0.4 parts of azobisisobutyronitrile, and keep warm for 2 hours after initiating the reaction. Drop the remaining 1 / 2 of the mixed precursor solution and 60 parts of ethyl acetate. After the drop is completed, add 0.4 parts of the formulation of azobisisobutyronitrile, heat to 85°C and keep warm for 2 hours, add another 0.4 parts of azobisisobutyronitrile, keep warm for 1 hour, cool and discharge to obtain the acrylate polymer with infrared absorber chemical modification.

[0064] S2. Preparation of a removable infrared absorption protective film:

[0065] (1) Weigh 100 parts of the acrylate polymer modified with infrared absorber, 5 parts of the tackifying resin and 1.5 parts of the curing agent, mix and stir, and then coat it evenly on one side of the 36μm PET substrate layer 1. The dry film thickness of the coating is 10μm. Dry it at 110℃ for 3min to obtain a high-viscosity infrared absorption layer. Then attach the side of the high-viscosity infrared absorption layer without the substrate to the 23μm PET substrate layer 2 to obtain an infrared absorption interlayer.

[0066] (2) Weigh 100 parts of low-viscosity acrylic adhesive and 2 parts of isocyanate curing agent, mix and stir, and then coat evenly on the substrate layer 2 of the infrared absorption interlayer. The dry film thickness of the coating is 12μm. Dry at 110℃ for 3min to obtain a low-viscosity adhesive layer. On the side of the low-viscosity adhesive layer without the substrate layer 2, attach a 25μm release film to obtain a release layer, and then obtain a removable infrared absorption protective film.

[0067] Comparative Example 1:

[0068] A removable infrared absorption protective film was prepared using the same method as in Example 1, except that KH-570 was used as the silane coupling agent.

[0069] Comparative Example 2:

[0070] A removable infrared absorption protective film was prepared using the same method as in Example 1, except that 3-aminopropyltrimethoxysilane was used as the silane coupling agent.

[0071] Comparative Example 3:

[0072] A removable infrared absorbing protective film was prepared using the same method as in Example 1, except that the dry film thickness of the high-viscosity infrared absorbing layer was 16 μm.

[0073] Comparative Example 4:

[0074] A removable infrared absorbing protective film was prepared using the same method as in Example 1, except that the dry film thickness of the high-viscosity infrared absorbing layer was 3 μm.

[0075] Comparative Example 5:

[0076] A removable infrared absorbing protective film was prepared using the same method as in Example 1, except that the amount of surface-modified infrared absorber added was 35 parts when preparing the chemically modified acrylate polymer for infrared absorbers.

[0077] Comparative Example 6:

[0078] A removable infrared absorbing protective film was prepared using the same method as in Example 1, except that when preparing the acrylate polymer with the infrared absorber chemically modified, the amount of surface-modified infrared absorber added was 4 parts.

[0079] Comparative Example 7:

[0080] (1) Weigh 30 parts of ATO powder with a particle size of 30 nm and 30 parts of ethanol, mix them and stir ultrasonically for 30 min to obtain mixture 1. Add mixture 1 and 1 part of 3-acryloylaminopropyltrimethoxysilane to a reaction flask with a stirrer, adjust the pH of the system to 4, let it stand for 30 min and then heat it to 50 °C. React it under stirring for 2 h, cool it to room temperature and centrifuge it. Wash it twice with ethanol and dry it at 55 °C to obtain the surface-modified infrared absorber.

[0081] (2) Weigh 100 parts of low-viscosity acrylic adhesive, 2 parts of isocyanate curing agent and 14 parts of surface-modified infrared absorber, mix and stir, and then uniformly coat it on one side of the 23μm PET substrate layer 2. The dry film thickness of the coating is 12μm. Dry it at 110℃ for 3min to obtain a low-viscosity adhesive layer. Then, attach a 25μm release film to the side of the low-viscosity adhesive layer without the substrate layer 2 to obtain a release layer, and then obtain a removable infrared absorption protective film.

[0082] Comparative Example 8:

[0083] (1) Weigh 30 parts of ATO powder with a particle size of 30 nm and 30 parts of ethanol, mix them and stir ultrasonically for 30 min to obtain mixture 1. Add mixture 1 and 1 part of 3-acryloylaminopropyltrimethoxysilane to a reaction flask with a stirrer, adjust the pH of the system to 4, let it stand for 30 min and then heat it to 50 °C. React it under stirring for 2 h, cool it to room temperature and centrifuge it. Wash it twice with ethanol and dry it at 55 °C to obtain the surface-modified infrared absorber.

[0084] (2) Weigh 14 parts of the surface-modified infrared absorber prepared in step (1), 85 parts of soft monomer: ethyl acrylate, 24 parts of hard monomer: methyl methacrylate, and 1 part of functional monomer: hydroxyethyl methacrylate. Mix them evenly to obtain a mixed precursor solution. Under nitrogen protection, add 1 / 2 of the mixed precursor solution and 60 parts of ethyl acetate to the reactor, heat to 70°C, add 0.4 parts of azobisisobutyronitrile, and keep warm for 2 hours after initiating the reaction. Drop the remaining 1 / 2 of the mixed precursor solution and 60 parts of ethyl acetate. After the drop is complete, add 0.4 parts of the formulation of azobisisobutyronitrile, heat to 85°C and keep warm for 2 hours. Add another 0.4 parts of azobisisobutyronitrile, keep warm for 1 hour, cool and discharge to obtain the acrylate polymer with infrared absorber chemical modification.

[0085] S2. Preparation of a removable infrared absorption protective film:

[0086] Weigh 100 parts of the chemically modified acrylate polymer with infrared absorber, 5 parts of the tackifying resin and 1 part of the curing agent, mix and stir, and then uniformly coat it on one side of the 23μm PET substrate layer 2. The dry film thickness of the coating is 12μm. Dry it at 110℃ for 3min to obtain a high-viscosity infrared absorption layer. Then, attach a 25μm release film to the side of the high-viscosity infrared absorption layer without the substrate layer 2 to obtain a release layer, and thus obtain a removable infrared absorption protective film.

[0087] experiment

[0088] 1. Adhesive layer thickness: ① Before use, clean the two contact surfaces of the thickness gauge and calibrate the zero position. Repeat the zeroing process 3 times before testing; ② When using, press the hand with your thumb and slowly raise the upper probe. Place the sample between the planes of the upper and lower measuring heads of the thickness gauge, with the adhesive side facing up. Slowly lower the upper probe and record the thickness gauge reading within 1 second after lowering the upper probe; ③ Measure three points for each sample and take the arithmetic mean of the three readings as the thickness value.

[0089] 2. Infrared and visible light transmittance: The ultraviolet-visible spectrophotometer was used for testing. The specific steps are as follows: ① Turn on the ultraviolet-visible spectrophotometer and preheat it; ② Select the spectral mode and perform blank baseline calibration; ③ Cut a 25mm×25mm sample to be tested, attach it parallel to a clean glass slide, place it on the sample cell holder, and close the sample chamber; ④ Measure the transmittance in the wavelength range of 400nm-980nm.

[0090] 3. 180° Peel Force: ① Inspect the test plate for cleanliness and absence of scratches or marks; ② Dampen a small square of lint-free cloth with an appropriate amount of anhydrous ethanol and wipe the surface of the test plate from top to bottom. Once clean, wipe again with a clean lint-free cloth until the surface is clean, then let it stand for 5 minutes; ③ Cut a sample to be tested into pieces 25±1mm wide and 300±20mm long, and attach them parallel to the steel plate (lightly press the sample with a small rubber roller to ensure it adheres to the test plate, and avoid air bubbles); ④ Use... ⑤ Roll the electric pressure roller back and forth on the test piece once at a speed of 300 mm / min under its own weight, and let it rest for 20 minutes; ⑥ Peel the adhesive surface off the test plate along the free end of the test piece, and clamp the free end of the test piece and the test plate tightly on the upper and lower clamps respectively, and make sure that the peeling surface is aligned with the force line of the peeling test machine; ⑦ Peel the tape on the tensile testing machine at a speed of 300 mm / min, and take the average value of the stroke 50 mm-150 mm; ⑦ Repeat the above experiment and take the average value of 3 tests, which is the final value. (Note: The peeling force at room temperature is tested directly after resting for 20 minutes; the peeling force of the 65℃ / 90%RH bonding aging test needs to be placed in a 65℃ / 90%RH oven for 72 hours after step ④, and then placed for 24 hours before testing.)

[0091] 5. Stain Resistance (Reworkability): ① After removing 3 to 4 turns from the sample plate or sample roll, cut a test piece with a width of 25±1mm and a length of 300±20mm, and attach it parallel to the steel plate (lightly press the test piece with a small rubber roller to make it adhere to the test plate, and no air bubbles are allowed); ② Use an electric pressure roller to roll back and forth on the test piece once at a speed of 300mm / min under its own weight. After placing it at 80℃ for 24 hours, visually observe the contamination status of the surface of the object after removing the infrared absorption protective film.

[0092]

[0093] As can be seen from the data in the table above, the infrared absorption protective films obtained in Examples 1-3 and Comparative Examples 1-8 are compared. The test results show that the infrared absorption protective films obtained in Examples 1-3 have sufficient adhesion to prevent them from falling off, whether under normal temperature or humid conditions. They can achieve the protective effect while meeting the harsh transportation conditions of high temperature and high humidity. They also have excellent infrared light shielding effect and visible light transmittance. In addition, the protective film can be easily removed after use, and there is no residue or ghosting on the surface of the object.

[0094] Compared with Example 1, the types of silane coupling agents used in Comparative Examples 1 and 2 are not within the scope defined in this application. The coupling effect between the infrared absorber and the acrylate polymer in Comparative Examples 1 and 2 is poor, resulting in a decrease in the visible light shielding effect and visible light transmittance of the final infrared absorption protective film, which cannot meet the infrared shielding requirements in the process.

[0095] Compared with Example 1, the dry film thickness of the high-viscosity infrared absorption layer in Comparative Example 3 is 16 μm, which is higher than 12 μm in Example 1. The increased thickness of the infrared absorption layer significantly improves the infrared shielding capability of the infrared absorption protective film, but its visible light transmittance is greatly reduced, which cannot meet the visible light transmittance requirements.

[0096] Compared with Example 1, the dry film thickness of the high-viscosity infrared absorption layer in Comparative Example 4 is 3 μm, which is lower than 12 μm in Example 1. Although the reduced thickness of the infrared absorption layer increases the visible light transmittance of the infrared absorption protective film, its infrared shielding ability is greatly reduced and it cannot effectively shield infrared light.

[0097] Compared with Example 1, the amount of surface-modified infrared absorber added to the high-viscosity infrared absorption layer in Comparative Example 5 was 35 parts. The increase of infrared absorber and silane coupling agent greatly improved the infrared shielding ability, but it reduced the viscosity of the high-viscosity infrared absorption layer and could not effectively bond the substrate. This would lead to displacement and detachment of the infrared absorption layer under harsh transportation conditions of high temperature and high humidity.

[0098] Compared with Example 1, the amount of surface-modified infrared absorber added to the high-viscosity infrared absorption layer in Comparative Example 6 was 4 parts. The reduction in the amount of infrared absorber and silane coupling agent significantly reduced the infrared shielding capability of the infrared absorption protective film.

[0099] Compared with Example 1, in Comparative Example 7, the silane-modified infrared absorber was directly added to the low-tack adhesive layer. Compared with Example 1, there was no sandwich structure. This resulted in a significant reduction in the peel force of the low-tack adhesive layer on the surface of the object being bonded, which could not meet the bonding protection requirements. At the same time, the infrared absorber precipitated out after the infrared absorption protective film was removed, which contaminated the surface of the object being bonded.

[0100] Compared with Example 1, in Comparative Example 8, the high-viscosity infrared absorption layer was directly bonded to the surface of the object. The high viscosity made it difficult to peel off the object, and after peeling, a large amount of residual adhesive remained on the surface of the object, affecting its appearance.

[0101] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are exhaustively listed. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0102] For those skilled in the art, various modifications and improvements can be made without departing from the concept of the present invention, and these modifications and improvements are all within the scope of protection of the present invention. The scope of protection of the present invention is defined by the appended claims.

Claims

1. A high viscosity infrared absorbing layer characterized in that, The high adhesion infrared absorption layer comprises an infrared absorption agent chemically modified acrylate polymer, a tackifying resin and a curing agent, wherein the infrared absorption agent chemically modified acrylate polymer is obtained by free radical copolymerization of an infrared absorption agent modified by a silane coupling agent containing an acrylamide group and an acrylic monomer; The preparation raw materials of the infrared absorption agent chemically modified acrylate polymer comprise, in terms of mass parts, 5-30 parts of an infrared absorption agent, 0.2-1 part of a silane coupling agent containing an acrylamide group, 60-90 parts of a soft monomer, 5-30 parts of a hard monomer, 0.1-5 parts of a functional monomer, 0.1-2 parts of an initiator and 100-160 parts of a solvent; The mass ratio of the infrared absorption agent chemically modified acrylate polymer and the curing agent in the high adhesion infrared absorption layer is 100: (0.1-2), and the curing agent is an epoxy curing agent and / or a metal salt curing agent; The silane coupling agent containing an acrylamide group is 3-acrylamidopropyl trimethoxysilane; The 180° peeling force of the high adhesion infrared absorption layer at room temperature is 2500-3000 gf / in, and the 180° peeling force after 65℃ / 90%RH bonding aging is 2800-3300 gf / in; The infrared absorbers are one or more of indium tin oxide (ITO), antimony tin oxide (ATO), cesium doped tungsten bronze (Cs X WO3), and lanthanum hexaboride (LaB6). The functional monomer is one or more of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate and hydroxybutyl acrylate.

2. The high viscosity infrared absorbing layer of claim 1, wherein: The particle size of the infrared absorption agent is 20-100 nm.

3. A high viscosity infrared absorbing layer according to claim 2, wherein The soft monomer is one or more of 2-ethylhexyl acrylate, ethyl acrylate, lauryl acrylate, n-octyl methacrylate and octadecyl methacrylate, and the hard monomer is one or more of methyl acrylate, methyl methacrylate, vinyl acetate, isobornyl methacrylate and acrylonitrile.

4. The method of claim 1-3, wherein the high viscosity infrared absorbing layer is prepared by the steps of: The method comprises the following steps: S1, the infrared absorption agent and ethanol are weighed according to the formula amount, mixed and then ultrasonically stirred for 20-40 min to obtain a mixed solution 1, the mixed solution 1 and the formula amount of the silane coupling agent containing an acrylamide group are added to a reaction bottle with a stirrer, the pH of the system is adjusted to weak acidity, and after standing for 20-40 min, the temperature is raised to 45-55℃, and the reaction is carried out under stirring for 2-3 h, and then the system is cooled to room temperature and centrifuged, washed with ethanol for 2-3 times and dried at 50-60℃ to obtain the surface-modified infrared absorption agent; S2, the surface-modified infrared absorption agent prepared in step S1, the soft monomer, the hard monomer, the functional monomer and the solvent are weighed according to the formula amount and uniformly mixed to obtain a mixed precursor solution; under nitrogen protection, 1 / 2 of the formula mass of the mixed precursor solution is added to a reactor, heated to 60-70℃, 1 / 3 of the formula mass of the initiator is added, the reaction is initiated, and after 2 h of heat preservation, the remaining 1 / 2 of the mixed precursor solution is added dropwise, after the dropwise addition is completed, 1 / 3 of the formula mass of the initiator is added, the temperature is raised to 85℃ for 2 h of heat preservation, and then the remaining 1 / 3 of the initiator is added, and heat preservation is carried out for 1 h, and then the system is cooled and discharged to obtain the infrared absorption agent chemically modified acrylate polymer; S3, the infrared absorption agent chemically modified acrylate polymer, the tackifying resin and the curing agent are uniformly mixed and coated according to the predetermined thickness requirement to obtain the high adhesion infrared absorption layer.

5. A removable infrared absorbing protective film, characterized by, The infrared absorption protective film is composed of a substrate layer 1, a high-adhesion infrared absorption layer, a substrate layer 2, a low-adhesion adhesive layer and a release layer which are sequentially stacked, wherein the high-adhesion infrared absorption layer is the high-adhesion infrared absorption layer according to any one of claims 1-3, and the thickness of the high-adhesion infrared absorption layer is 6-15 μm.

6. A removable infrared absorbing protective film according to claim 5, wherein The infrared absorption protective film has an infrared light transmittance of 12-19% and a visible light transmittance of 55-73%.

7. The removable infrared absorbing protective film according to claim 5, wherein The low-adhesion adhesive layer is an acrylate pressure-sensitive adhesive, and includes, in terms of mass parts, 100 parts of a low-adhesion acrylate adhesive, and 0.5-3 parts of a curing agent.

8. The removable infrared absorbing protective film according to claim 5, wherein The low-adhesion adhesive layer has a thickness of 10-20 μm, a 180° peeling force at room temperature of 30-70 gf / in, and a 180° peeling force after 65°C / 90% RH bonding aging of 40-90 gf / in.

9. A method of producing a removable infrared-absorbing protective film according to any one of claims 6 to 8, characterized in that, The method comprises the following steps: S1. Preparation of an infrared absorption interlayer: An infrared absorption agent chemically modified acrylate polymer, a tackifying resin and a curing agent are weighed according to the formula amount, stirred uniformly, coated on one side surface of the substrate layer 1 according to the thickness requirement, and heated and cured at 100-120°C to obtain a high-adhesion infrared absorption layer. The high-adhesion infrared absorption layer without the substrate is bonded to the substrate layer 2 to obtain an infrared absorption interlayer. S2. Preparation of a removable infrared absorption protective film: A low-adhesion acrylate adhesive and a curing agent are weighed according to the formula amount, mixed and stirred, uniformly coated on the substrate layer 2 of the infrared absorption interlayer according to the thickness requirement, heated and cured at 100-120°C to obtain a low-adhesion adhesive layer, and a release film is bonded to the side of the low-adhesion adhesive layer without the substrate layer 2 to obtain a release layer, and further obtain a removable infrared absorption protective film.

10. Use of a removable infrared absorption protective film in the production process of an infrared camera, characterized in that, The removable infrared absorption protective film is the removable infrared absorption protective film according to any one of claims 6-8.

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