Yellow light sharp absorption / near-infrared cut-off type absorption double-layer transparent heat insulation film and preparation method thereof

Abstract

The invention belongs to the field of transparent heat insulation materials, and relates to a yellow light sharp absorption / near-infrared cut-off absorption double-layer transparent heat insulation film and a preparation method thereof. The double-layer transparent heat insulation film is formed by compounding the PET layer containing the cesium-tungsten bronze and the PVB layer containing the organic yellow light absorbent, the absorption or reflection capacity of the PET layer to near-infrared light is remarkably enhanced by adding the cesium-tungsten bronze, heat of the wave band of 780-2500 nm is effectively prevented from entering the film, the organic yellow light absorbent is specially used for absorbing yellow light of the wave band of 560-590 nm, and the heat insulation effect is good. And the limitation of a traditional material on regulation and control of a specific wave band is improved. Besides, by accurately controlling the mass fraction of each component, including the selection and usage amount of the dispersing agent, the type of the solvent and the like, good compatibility and dispersity among the materials are ensured, so that the overall performance of the film is improved.

Description

Technical Field

[0001] The present invention belongs to the field of transparent heat-insulating materials, and relates to a double-layer transparent heat-insulating film with sharp yellow light absorption / near-infrared cut-off absorption and a preparation method thereof. Background Art

[0002] With the intensification of the global energy crisis and environmental problems, the research and application of energy-saving and environmental-friendly materials have become the focus in various fields. As an advanced material with optical regulation and heat-insulating functions, the application demand of transparent heat-insulating materials in the fields of building energy conservation, automotive glass, and optical devices is increasing continuously. By effectively blocking specific bands in the solar spectrum (such as near-infrared light and part of visible light), such materials can significantly reduce heat transfer while maintaining a high visible light transmittance, thus achieving the dual goals of energy conservation and comfort.

[0003] In the prior art, the research on transparent heat-insulating films mainly focuses on two types of materials: heat-insulating films based on inorganic nanoparticles and heat-insulating films based on organic dyes. Inorganic nanoparticles (such as antimony-doped tin oxide and cesium tungsten bronze) have become one of the main choices for transparent heat-insulating films due to their excellent near-infrared absorption performance. These materials can effectively absorb or reflect near-infrared light in the band of 780 - 2500 nm, thereby blocking the heat brought by solar radiation. However, the functional singularity of inorganic nanoparticles is an obvious shortcoming. They mainly absorb or reflect in the near-infrared band and lack selective regulation for specific bands in visible light, such as the yellow light band (560 - 590 nm), which performs poorly in some application scenarios where glare reduction or light environment optimization is required. In addition, poor dispersibility will also cause a decrease in the visible light transmittance of the film, affecting transparency, especially when mixed with other dyes, this compatibility problem is more prominent.

[0004] In contrast, heat-insulating films based on organic dyes achieve heat-insulating effects through the absorption of light in specific bands by organic molecules. The advantages of such materials are simple preparation processes and flexible color regulation. However, the absorption bandwidth of a single organic dye is limited, and it can usually only absorb light in specific bands, making it difficult to cover both near-infrared light and the yellow light band in visible light simultaneously, which has a certain impact on the overall heat-insulating performance. In addition, whether using inorganic nanoparticles or organic dyes, most of the current preparation processes of transparent heat-insulating films adopt a single-functional layer design (such as a metal oxide coating or an organic dye coating). This single-layer structure has problems such as poor interfacial bonding force and easy delamination, and it is difficult to meet the needs of long-term use in complex environments. At the same time, the spectral regulation ability of single-layer materials is limited, and it is impossible to simultaneously take into account multi-spectral selective absorption and high transparency, restricting the potential of its application in more scenarios.

[0005] The Chinese patent application document (CN104610710A) discloses a highly efficient ultraviolet and near-infrared blocking PET film and its preparation method. However, the dispersion of cesium tungsten bronze and antimony tin oxide nanoparticles in the PET matrix has not been fully solved. Although a dispersant is added, the specific dispersion process is not specified, which will cause agglomeration to a certain extent and affect the uniformity of the film transparency and heat insulation performance.

[0006] The Chinese patent application document (CN116515261A) discloses a cesium tungsten bronze composite PET material, its preparation method and application. It only realizes ultraviolet and near-infrared blocking through a single-layer PET film, lacks selective absorption in the yellow light band (560 - 590nm), and cannot achieve multi-spectral (near-infrared + yellow light) synergistic regulation, resulting in insufficient performance in scenarios such as reducing glare and optimizing the light environment. Summary of the Invention

[0007] The object of the present invention is to address the above-mentioned problems existing in the prior art, and propose a double-layer transparent heat insulation film with sharp yellow light absorption / near-infrared cut-off absorption, which solves the problems of single function, insufficient durability and poor interfacial bonding force of traditional heat insulation materials through the optimized design of the multi-layer structure.

[0008] The object of the present invention can be achieved by the following technical solutions: A double-layer transparent heat insulation film with sharp yellow light absorption / near-infrared cut-off absorption, the double-layer transparent heat insulation film is composed of a PET layer containing cesium tungsten bronze and a PVB layer containing an organic yellow light absorber. The PVB layer containing the organic yellow light absorber includes the following raw materials in parts by mass: 0.1 - 1 part of the organic yellow light absorber, 5 - 10 parts of PVB, and 80 - 90 parts of the solvent; The organic yellow light absorber has the following structure: , n = 10 - 15; The preparation method of the organic yellow light absorber includes the following steps: uniformly stirring and reacting bisphenol A diglycidyl ether and 2,6 - di-tert-butyl-p-(dimethylaminomethyl)phenol with N,N-dimethylformamide as the solvent.

[0009] The design concept of the yellow light absorber in the present invention is to achieve the synergistic performance of "high selectivity, high light transmittance, and high compatibility" through fine regulation at the molecular level. By high selectivity, it means that the absorber can specifically absorb light in the yellow light band without interfering with light in other bands, thus effectively reducing the glare problem. High light transmittance means that even with the addition of the absorber, the material can still maintain a high visible light transmittance, ensuring good visual clarity. And high compatibility means that this absorber can be well compatible with PVB to form a stable composite layer, which not only enhances the overall performance of the material but also broadens its application range. In addition, this organic yellow light absorber can achieve high efficiency with a low addition amount, further enhancing its practical value. A small amount of the absorber can significantly improve the yellow light absorption efficiency while avoiding the decline of other optical properties caused by excessive use, such as the reduction of visible light transmittance. This not only reduces costs but also simplifies the production process, making the final product more environmentally friendly and economical.

[0010] In the above-mentioned double-layer transparent heat-insulating film with sharp yellow light absorption / near-infrared cut-off absorption, the molar ratio of bisphenol A diglycidyl ether to 2,6-di-tert-butyl-p-(dimethylaminomethyl)phenol is 1:(0.5 - 1.5). The present invention ensures the complete reaction of the epoxy group of bisphenol A diglycidyl ether with the tertiary amino group by controlling the molar ratio of bisphenol A diglycidyl ether to 2,6-di-tert-butyl-p-(dimethylaminomethyl)phenol to form a linear polymer chain and avoid branching or cross-linking. An imbalance in the ratio will lead to the residue of unreacted monomers or cross-linking, resulting in abnormal molecular weight and affecting the optical properties of the film.

[0011] In the above-mentioned double-layer transparent heat-insulating film with sharp yellow light absorption / near-infrared cut-off absorption, the stirring reaction temperature is 85 - 95 °C and the time is 8 - 12 h.

[0012] In the above-mentioned double-layer transparent heat-insulating film with sharp yellow light absorption / near-infrared cut-off absorption, the number-average molecular weight Mn of the organic yellow light absorber is 8000 - 9000, and the weight-average molecular weight Mw is 10000 - 11000. In the present invention, an excess of 2,6-di-tert-butyl-p-(dimethylaminomethyl)phenol will result in too low a molecular weight, a decline in yellow light absorption performance, and poor thermal stability; an excess of bisphenol A diglycidyl ether will form a cross-linked structure to form a high-molecular-weight product, resulting in poor solubility and a decline in absorption performance.

[0013] In the above-mentioned double-layer transparent heat-insulating film with sharp yellow light absorption / near-infrared cut-off absorption, the thickness ratio of the Cs-containing tungsten bronze PET layer to the PVB layer containing the organic yellow light absorber is 2 - 4:1 - 3.

[0014] In the above-mentioned double-layer transparent heat-insulating film with sharp yellow light absorption / near-infrared cut-off absorption, the thickness of the PET layer containing cesium tungsten bronze is 20 - 40 μm, and the thickness of the PVB layer containing organic yellow light absorber is 10 - 30 μm.

[0015] In the present invention, for the PET layer containing cesium tungsten bronze, the thickness is selected in the range of 20 - 40 μm, mainly to ensure effective blocking of near-infrared radiation (780 - 2500 nm band) while maintaining a high visible light transmittance. As an efficient near-infrared absorption material, the application of cesium tungsten bronze in this layer can significantly reduce heat transfer, and an appropriate thickness ensures both effective heat blocking and prevention of a significant decrease in visible light transmittance due to excessive thickness, thus affecting transparency and visual comfort. Regarding the PVB layer containing organic yellow light absorber, the thickness is set between 10 - 30 μm, which is considered for the balance between yellow light absorption efficiency and visible light transmittance. If the yellow light absorption layer is too thin (less than 10 μm), it may result in insufficient yellow light absorption rate and fail to achieve the expected heat-insulating effect, especially obvious in application scenarios where specific wavelength light needs to be optimized. On the contrary, if this layer is too thick (more than 30 μm), although the yellow light absorption rate can be increased, it will be at the cost of sacrificing visible light transmittance, resulting in poor overall light transmittance.

[0016] In the above-mentioned double-layer transparent heat-insulating film with sharp yellow light absorption / near-infrared cut-off absorption, the PET layer containing cesium tungsten bronze comprises raw materials in the following mass parts: 10 - 30 parts of cesium tungsten bronze, 0.5 - 2 parts of dispersant, 60 - 90 parts of solvent, and 65 - 90 parts of PET resin.

[0017] The dispersant includes at least one of surfactant, polymer dispersant, and silane coupling agent.

[0018] Preferably, the solvent is at least one of ethanol, ethyl acetate, and isopropanol.

[0019] The present invention also provides a preparation method of a double-layer transparent heat-insulating film with sharp yellow light absorption / near-infrared cut-off absorption, and the method comprises the following steps: S1. Add cesium tungsten bronze into the solvent, then add the dispersant for uniform mixing and dispersion, then add the PET resin for stirring, and then prepare the PET layer containing cesium tungsten bronze through extrusion granulation and film drawing; S2. Add PVB into the solvent for mixing, and then add the organic yellow light absorber for uniform stirring to obtain a coating; S3. Uniformly coat the coating on the surface of the PET layer containing cesium tungsten bronze, and obtain the double-layer transparent heat-insulating film after curing.

[0020] In the preparation method of the above-mentioned double-layer transparent heat-insulating film with sharp yellow light absorption / near-infrared cut-off absorption, the extrusion temperature in step S1 is 200-250°C, and the film drawing speed is 5-10 m / min.

[0021] Preferably, the curing temperature is 40-60°C and the time is 5-20 min.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The double-layer transparent heat-insulating film of the present invention is composed of a PET layer containing cesium tungsten bronze and a PVB layer containing an organic yellow light absorber. The addition of cesium tungsten bronze significantly enhances the ability of the PET layer to absorb or reflect near-infrared light, effectively blocking the heat in the 780-2500 nm band from entering, while the organic yellow light absorber specifically absorbs the yellow light in the 560-590 nm band, improving the limitations of traditional materials in specific band regulation. In addition, by precisely controlling the mass fractions of each component, including the selection and usage amount of the dispersant, the type of solvent, etc., good compatibility and dispersibility between the materials are ensured, thereby improving the overall performance of the film.

[0024] 2. In the preparation process of the double-layer transparent heat-insulating film of the present invention, the temperature and speed are strictly controlled, ensuring the consistency and stability of the material quality. In particular, by adjusting reaction conditions such as temperature, time, and the molar ratio of raw materials, an organic yellow light absorber with a specific molecular weight can be customized, further optimizing its optical properties.

[0025] 3. The biggest highlight of the double-layer transparent heat-insulating film of the present invention is that it achieves excellent performance with a near-infrared absorption rate greater than 75% and a yellow band absorption rate greater than 80%. This not only means a more efficient heat-insulating effect but also provides better visual comfort. More importantly, the design of this double-layer structure greatly improves the durability and interfacial bonding force of the material, enabling it to work stably for a long time in complex environments, meeting the requirements of high-performance transparent heat-insulating materials in multiple fields such as building energy conservation and automotive glass. Description of the Drawings

[0026] Figure 1 It is the synthesis route diagram of the organic yellow absorber in Example 1; (a). The synthesis path diagram of the organic yellow absorber, (b). The liquid-phase physical diagram of the organic yellow absorber, (c). The solid-phase physical diagram of the organic yellow absorber, (d). The physical diagram of the yellow light absorber spin-coated on a ceramic sheet.

[0027] Figure 2 It is the UV-VIS-NIR spectrogram of Example 1 and Comparative Examples 1-3. Detailed Embodiments

[0028] The following are specific embodiments of the present invention, which further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments. Example 1

[0029] S1. Add 20 parts of cesium tungsten bronze to 80 parts of ethyl acetate by mass, then add 1 part of silane coupling agent KH-550 for uniform mixing and dispersion, then add 80 parts of PET resin and stir, and then extrude and pelletize at 240 °C, and prepare a PET layer containing cesium tungsten bronze with a thickness of 30 μm at a film drawing speed of 8 m / min;

[0030] S2. As shown in Figure 1 (a), put bisphenol A diglycidyl ether (DGEBA) and 2,6-di-tert-butyl-p-(dimethylaminomethyl)phenol in a molar ratio of 1:1 in a three-necked flask, and react at 90 °C for 10 h with N,N-dimethylformamide (DMF) as the solvent to obtain Figure 1 the organic yellow light absorber shown in (b), and the structure of the organic yellow light absorber is as follows: , n = 13; The physical picture of the organic yellow light absorber after drying is as shown in Figure 1 (c), and the physical picture of the yellow light absorber spin-coated on the ceramic chip is as shown in Figure 1 (d);

[0031] S2. Add 8 parts of PVB to 80 parts of ethyl acetate by mass for mixing, and then add 0.5 part of the organic yellow light absorber and stir evenly to obtain a coating;

[0032] S3. Uniformly roll the coating on the surface of the PET layer containing cesium tungsten bronze. Among them, a coating rod with a coating thickness of 100 microns is used for rolling, and the coating speed is 8 mm / s to obtain a 15-μm PVB coating layer containing the organic yellow light absorber. Finally, it is cured at 45 °C for 10 min to obtain a double-layer transparent heat-insulating film. Example 2

[0033] S1. Add 20 parts of cesium tungsten bronze to 80 parts of ethyl acetate by mass, then add 1 part of silane coupling agent KH-550 for uniform mixing and dispersion, then add 80 parts of PET resin and stir, and then extrude and pelletize at 240 °C, and prepare a PET layer containing cesium tungsten bronze with a thickness of 30 μm at a film drawing speed of 8 m / min;

[0034] S2. Put bisphenol A diglycidyl ether (DGEBA) and 2,6-di-tert-butyl-p-(dimethylaminomethyl)phenol in a molar ratio of 1:1 in a three-necked flask, and react at 90 °C for 10 h with N,N-dimethylformamide (DMF) as the solvent to obtain an organic yellow light absorber;

[0035] S3. Add 8 parts of PVB to 80 parts of ethyl acetate by mass fraction, mix them, and then add 0.2 part of organic yellow light absorber and stir evenly to obtain a coating;

[0036] S4. Roll the coating evenly on the surface of the CsWO3-bronze-containing PET layer. Among them, a coating rod with a coating thickness of 100 μm is used for rolling, and the coating speed is 8 mm / s to obtain a 15-μm PVB coating layer containing an organic yellow light absorber. Finally, after curing at 45 °C for 10 min, a double-layer transparent heat-insulating film is obtained. Example 3

[0037] S1. Add 20 parts of CsWO3-bronze to 80 parts of ethyl acetate by mass fraction, then add 1 part of silane coupling agent KH-550 and mix and disperse them evenly. Then add 80 parts of PET resin and stir. Then, extrude and granulate at 240 °C, and prepare a CsWO3-bronze-containing PET layer with a thickness of 30 μm at a film drawing speed of 8 m / min;

[0038] S2. Place bisphenol A diglycidyl ether (DGEBA) and 2,6-di-tert-butyl-p-(dimethylaminomethyl)phenol in a three-necked flask at a molar ratio of 1:1, and react at 90 °C for 10 h with N,N-dimethylformamide (DMF) as the solvent to prepare an organic yellow light absorber;

[0039] S3. Add 8 parts of PVB to 80 parts of ethyl acetate by mass fraction, mix them, and then add 0.1 part of organic yellow light absorber and stir evenly to obtain a coating;

[0040] S4. Roll the coating evenly on the surface of the CsWO3-bronze-containing PET layer. Among them, a coating rod with a coating thickness of 100 μm is used for rolling, and the coating speed is 8 mm / s to obtain a 15-μm PVB coating layer containing an organic yellow light absorber. Finally, after curing at 45 °C for 10 min, a double-layer transparent heat-insulating film is obtained. Example 4

[0041] The difference from Example 1 is only that the thickness of the PVB layer containing the organic yellow light absorber is 5 μm. Example 5

[0042] The difference from Example 1 is only that the thickness of the PVB layer containing the organic yellow light absorber is 50 μm. Example 6

[0043] The difference from Example 1 is only that the addition amount of the organic yellow light absorber in step S3 is 0.01 part. Example 7

[0044] The difference from Example 1 is only that the addition amount of the organic yellow light absorber in step S3 is 3 parts. Comparative Example 1

[0045] The PET resin was extruded and drawn into a film by a twin-screw extruder. The temperature of the process was 240 °C, and the film drawing speed was 8 m / min to obtain a 30-μm PET film. Comparative Example 2

[0046] A premixed masterbatch was prepared by mixing PET resin and cesium tungsten bronze dispersion liquid in a mass ratio of 76:24, and a 30-μm near-infrared cut-off absorption layer was formed by twin-screw extrusion granulation and film drawing. Comparative Example 3

[0047] S1. Bisphenol A diglycidyl ether (DGEBA) and 2,6-di-tert-butyl-p-(dimethylaminomethyl)phenol were placed in a three-necked flask in a molar ratio of 1:1, and reacted at 90 °C for 10 h in N,N-dimethylformamide (DMF) as a solvent to obtain an organic yellow light absorber;

[0048] S2. 8 parts of PVB were added to 80 parts of ethyl acetate by mass and mixed, and then 0.5 part of the organic yellow light absorber was added and stirred evenly to obtain a coating;

[0049] S3. The coating was evenly roll-coated on the surface of a common PET layer. The roll coating was carried out using a coating rod with a coating thickness of 100 μm, and the coating speed was 8 mm / s to obtain a 15-μm PVB coating layer containing the organic yellow light absorber. Finally, a single-layer sharp yellow light absorption film was obtained after curing.

[0050] Table 1: Transmittance of the films prepared in Examples 1-7 and Comparative Examples 1-3 at different wavelengths

[0051] Figure 2 The UV-VIS-NIR spectrograms of Example 1 and Comparative Examples 1-3. Example 1 (purple curve) has a high transmittance in the visible light region (380-780 nm), and at the same time, it shows a sharp absorption peak at 580 nm (the transmittance drops suddenly to less than 20%), and realizes near-infrared cut-off absorption. Its performance precisely combines the sharp yellow light absorption of Comparative Example 2 and the near-infrared cut-off absorption characteristics of Comparative Example 3.

[0052] In summary, the biggest highlight of the double-layer transparent heat-insulating film of the present invention is that it achieves excellent performance with a near-infrared absorption rate greater than 75% and a yellow light band absorption rate greater than 80%. This not only means more efficient heat-insulating effect, but also provides better visual comfort. More importantly, the design of this double-layer structure greatly improves the durability and interfacial bonding strength of the material, enabling it to work stably in complex environments for a long time, meeting the requirements of high-performance transparent heat-insulating materials in multiple fields such as building energy conservation and automotive glass.

[0053] For the points in the technical scope claimed by the present invention that are not exhausted in terms of numerical values, as well as the new technical solutions formed by equivalent replacements of single or multiple technical features in the technical solutions of the embodiments, they are also within the scope claimed by the present invention; at the same time, in all the listed or unlisted embodiments of the present invention, each parameter in the same embodiment only represents an example (i.e., a feasible solution) of its technical solution, and there is no strict cooperation and limitation relationship between the parameters. Among them, the parameters can be replaced with each other without violating the axioms and the requirements of the present invention, except as specifically stated.

[0054] The technical means disclosed in the present invention are not limited to the technical means disclosed above, but also include the technical solutions formed by any combination of the above technical features. The above is the specific implementation manner of the present invention. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements are also regarded as the protection scope of the present invention.

[0055] The specific embodiments described herein are only illustrative of the spirit of the present invention. Those skilled in the art of the present invention can make various modifications or supplements or use similar ways to replace the described specific embodiments, but will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. A double-layer transparent heat-insulating film with yellow light sharp absorption / near infrared cut-off absorption, characterized in that: The double-layer transparent heat-insulating film is composited by a PET layer containing cesium tungsten bronze and a PVB layer containing an organic yellow light absorber, wherein the PVB layer containing an organic yellow light absorber comprises the following raw materials in parts by weight: 0.1-1 parts of an organic yellow light absorber, 5-10 parts of PVB and 80-90 parts of a solvent; The organic yellow light absorber has the structure shown below: ，n=10~15； The preparation method of the organic yellow light absorber comprises the following steps: bisphenol A diglycidyl ether and 2,6-di-tert-butyl-p-(dimethylaminomethyl)phenol are uniformly stirred and reacted with N,N-dimethylformamide as solvent.

2. The double-layer transparent heat-insulating film with yellow light sharp absorption / near infrared cut-off absorption according to claim 1, characterized in that: The molar ratio of bisphenol A diglycidyl ether to 2,6-di-tert-butyl-p-(dimethylaminomethyl)phenol is 1:(0.5-1.5).

3. The double-layer transparent heat-insulating film with yellow light sharp absorption / near infrared cut-off absorption according to claim 1, characterized in that: The stirring reaction temperature is 85-95°C and the time is 8-12h.

4. The double-layer transparent heat-insulating film with yellow light sharp absorption / near infrared cut-off absorption according to claim 1, characterized in that: The number average molecular weight Mn of the organic yellow light absorber is 8000-9000, and the weight average molecular weight Mw is 10000-11000.

5. The double-layer transparent heat-insulating film with yellow light sharp absorption / near infrared cut-off absorption according to claim 1, characterized in that: The thickness ratio of the PET layer containing cesium tungsten bronze to the PVB layer containing the organic yellow light absorber is 2-4:1-3.

6. The double-layer transparent heat-insulating film with yellow light sharp absorption / near infrared cut-off absorption according to claim 1, characterized in that: The thickness of the PET layer containing cesium tungsten bronze is 20-40 μm, and the thickness of the PVB layer containing the organic yellow light absorber is 10-30 μm.

7. The double-layer transparent heat-insulating film with yellow light sharp absorption / near infrared cut-off absorption according to claim 1, characterized in that: The PET layer containing cesium tungsten bronze comprises the following raw materials in parts by weight: 10-30 parts of cesium tungsten bronze, 0.5-2 parts of dispersant, 60-90 parts of solvent and 65-90 parts of PET resin.

8. A method for preparing the double-layer transparent heat-insulating film with yellow light sharp absorption / near infrared cut-off absorption as claimed in claim 1, characterized in that: The method comprises the following steps: S1, adding cesium tungsten bronze to a solvent, then adding a dispersant to uniformly mix and disperse, then adding PET resin to stir, and then preparing a PET layer containing cesium tungsten bronze by extrusion granulation and film drawing; S2, adding PVB to the solvent and mixing, and then adding an organic yellow light absorber and stirring evenly to obtain a coating; S3, coating the coating evenly on the surface of the PET layer containing cesium tungsten bronze, and obtaining a double-layer transparent heat-insulating film after curing.

9. The method for preparing a double-layer transparent heat-insulating film with yellow light sharp absorption / near infrared cut-off absorption according to claim 8, characterized in that: In step S1, the extrusion temperature is 200-250° C. and the film drawing speed is 5-10 m / min.

10. The method for preparing a double-layer transparent heat-insulating film with yellow light sharp absorption / near infrared cut-off absorption according to claim 8, characterized in that: The curing temperature is 40-60°C and the curing time is 5-20 minutes.

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