Low stress pressure sensitive adhesive and coating process for integrated composite molding of retroreflective film

Abstract

The application discloses a low-stress pressure-sensitive adhesive and a coating process for integrally and complexly forming a retroreflective film, and relates to the technical field of coating processes. The low-stress pressure-sensitive adhesive is prepared from 45-55 parts of soft monomers, 17-23 parts of hard monomers, 4-6 parts of functional monomers, 8-12 parts of stabilizers, 1-2 parts of initiators and 20-25 parts of solvents in terms of mass fraction. The low-stress pressure-sensitive adhesive prepared by the application is suitable for long-term service requirements outdoors.

Description

Technical Field

[0001] This invention relates to the field of coating process technology, specifically to a low-stress pressure-sensitive adhesive and coating process for integrated composite molding of reflective films. Background Technology

[0002] As a core functional material in road traffic safety signs, intelligent transportation facilities, and outdoor security warnings, reflective film's service stability and reflective performance are highly correlated with its composite molding process and the performance of its supporting pressure-sensitive adhesive. With the rapid development of urban transportation in my country, higher requirements have been placed on the weather resistance, reflective consistency, and composite flatness of reflective film. Integrated composite molding technology, due to its short process, high production efficiency, and strong interlayer bonding, is gradually becoming the development direction in the reflective film manufacturing industry.

[0003] Currently, the acrylic pressure-sensitive adhesives used in integrated reflective film composites generally suffer from insufficient internal stress control. During the curing process, shrinkage and warping, as well as deformation of the microprism reflective structure, are prone to occur, leading to a decrease in reflectivity and uneven interlayer adhesion. At the same time, existing coating processes have defects such as unreasonable curing gradients and large tolerances in adhesive layer thickness, making it difficult to adapt to the requirements of continuous integrated molding. Problems such as bubbles, missed coatings, and poor release are prone to occur, and the yield of finished products is generally lower than 85%.

[0004] Furthermore, conventional tackifying resins and acrylate matrices have poor compatibility, and long-term outdoor service can easily lead to precipitation, exacerbating stress release within the adhesive layer and causing wrinkling and delamination of the reflective film, making it difficult to meet the requirement of more than 10 years of weather resistance. Therefore, based on the above situation, developing a low-stress pressure-sensitive adhesive suitable for integrated composite molding of reflective films is of great significance to the industry's development. Summary of the Invention

[0005] The purpose of this invention is to address the problems existing in the prior art by providing a low-stress pressure-sensitive adhesive and coating process for integrated composite molding of reflective films, which has low internal stress and excellent weather resistance, thereby improving the yield of finished reflective films and their long-term service stability.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A low-stress pressure-sensitive adhesive for integrated composite molding of reflective film is prepared from the following components in parts by weight: 45-55 parts of soft monomer, 17-23 parts of hard monomer, 4-6 parts of functional monomer, 8-12 parts of stabilizer, 1-2 parts of initiator, and 20-25 parts of solvent. By adopting the above technical solution, the stabilizer is further described as a core-shell structure stabilizer, which includes a mesoporous silica nanosphere core and a flexible antioxidant stabilizing shell coating the surface of the mesoporous silica nanosphere core.

[0007] By adopting the above technical solution, the flexible antioxidant stabilizing shell is further composed of a composite formed by trimethoxy-terminated polydimethylsiloxane and antioxidant 1010.

[0008] By adopting the above technical solution, the soft monomer is any one of isooctyl acrylate and isobutyl acrylate, or a combination thereof.

[0009] Furthermore, by adopting the above technical solution, the hard monomer is any one or a combination of methyl methacrylate and ethyl methacrylate.

[0010] Furthermore, by adopting the above technical solution, the functional monomer is any one of hydroxyethyl acrylate and hydroxypropyl acrylate, or a combination thereof.

[0011] Furthermore, by adopting the above technical solution, the method for preparing the stabilizer is as follows: A1. Preparation of the core dispersion: Weigh mesoporous silica nanospheres with an average particle size of 50 nm and a particle size distribution range of 45-55 nm, and add them to anhydrous ethanol, wherein 180-220 mL of anhydrous ethanol is added for every 10 g of mesoporous silica nanospheres; place the system under ice-water bath conditions for ultrasonic cavitation dispersion treatment, keep the system temperature at 0-5℃, the ultrasonic frequency at 20-25 kHz, the power density at 0.5-0.8 W / mL, and the ultrasonic time at 30-45 min; during the ultrasonic process, pause for 0.5-1.5 min every 4-6 min of ultrasonication, and after the ultrasonication is completed, continue stirring at a stirring speed of 300-500 r / min for 10-20 min to obtain the mesoporous silica core dispersion; A2. Preparation of the trimethoxy-terminated polydimethylsiloxane and antioxidant 1010 composite: Based on 100 parts by weight of the mesoporous silica nanospheres, weigh 55-70 parts by weight of trimethoxy-terminated polydimethylsiloxane and 12-18 parts by weight of antioxidant 1010, and add them to ethyl acetate, wherein 50-70 mL of ethyl acetate is added for every 10 g of mesoporous silica nanospheres; place the mixture at 40-50℃ and stir at 250-350 r / min for 20-40 min to dissolve and uniformly disperse antioxidant 1010 in the trimethoxy-terminated polydimethylsiloxane; then treat with an ultrasonic device at a frequency of 18-22 kHz and a power density of 0.3-0.5 W / mL for 8-15 min to obtain a trimethoxy-terminated polydimethylsiloxane / antioxidant 1010 composite solution; A3. Grafting and coating of a flexible antioxidant stabilizing shell: Under nitrogen protection, the mesoporous silica core dispersion obtained in A1 is heated to 65-70℃, and the stirring speed is controlled at 400-500 r / min; the trimethoxy-terminated polydimethylsiloxane / antioxidant 1010 composite solution obtained in A2 is added dropwise to the mesoporous silica core dispersion for 40-60 min; after the addition is completed, glacial acetic acid is added to adjust the pH of the system to 4.5-5.0, and the reaction is carried out at 65-70℃ with constant temperature stirring for 12-15 h, so that the trimethoxy-terminated polydimethylsiloxane and the silanol groups on the surface of the mesoporous silica undergo a hydrolysis and condensation reaction, and at the same time, the antioxidant 1010 is dispersed and fixed in the flexible shell formed by the trimethoxy-terminated polydimethylsiloxane, thus forming a flexible antioxidant stabilizing shell on the surface of the mesoporous silica nanospheres; A4. Phase change extraction and drying: After the reaction is completed, the reaction solution is cooled to 40-50℃ and transferred to a high-pressure reactor. Supercritical carbon dioxide fluid is introduced for phase change extraction and drying. The extraction and drying pressure is controlled at 15-20MPa, the temperature at 45-55℃, the carbon dioxide fluid flow rate at 2-4L / min, and the extraction and drying time at 2-4h. After extraction, the pressure is slowly released to atmospheric pressure at a rate of 0.3-0.8MPa / min, and the powder in the reactor is collected to obtain the stabilizer.

[0012] Furthermore, by adopting the above technical solution, the initiator is any one or a combination of benzoyl peroxide and dicumyl peroxide.

[0013] Furthermore, by adopting the above technical solution, the solvent is any one or a combination of ethyl acetate and butyl acetate.

[0014] A coating process for a low-stress pressure-sensitive adhesive used in the integrated molding of reflective films includes the following steps: S1. A method for preparing a low-stress pressure-sensitive adhesive for integrated composite molding of reflective films, comprising the following steps: S11. Take the soft monomer, hard monomer, functional monomer and solvent, add them to the reaction vessel, stir for 15-20 minutes, mix evenly to obtain a mixture; S12. Add the stabilizer to the reactor, heat to 58-62℃, and continue stirring for 35-45 minutes until the stabilizer is evenly dispersed; S13. Raise the temperature of the reactor to 72-78℃, add the initiator, stir and react for 3-4 hours to obtain a prepolymer; cool the prepolymer to 35-40℃, filter, and obtain the low-stress pressure-sensitive adhesive for integrated composite molding of reflective film. S2. A coating process for a low-stress pressure-sensitive adhesive used in the integrated molding of reflective films, comprising the following steps: S21. Pretreatment: The reflective film substrate is subjected to corona treatment with a power of 300-400W for 3-5 seconds to remove impurities and oil stains from the substrate surface. S22. Coating: Using a doctor blade coating method, the low-stress pressure-sensitive adhesive is evenly coated on the surface of the pretreated reflective film substrate at a coating speed of 1.5-2.5 m / min. S23. Curing: The coated reflective film is sent into a drying and curing oven and cured in three stages. The first stage is at a temperature of 80-90℃ for 20-30 seconds; the second stage is at a temperature of 100-110℃ for 30-40 seconds; and the third stage is at a temperature of 70-80℃ for 15-20 seconds. S24. Composite molding: The cured reflective film is laminated with release paper, and after lamination, it is naturally cooled to room temperature. The film is then wound up to obtain the coating process of the low-stress pressure-sensitive adhesive used for integrated composite molding of reflective film.

[0015] By adopting the above technical solution, furthermore, during the S13 reaction process, the stirring speed is adjusted every 40 minutes, with an adjustment range of 250-300 r / min.

[0016] By adopting the above technical solution, furthermore, during the S24 reaction process, the bonding speed and the coating speed are kept consistent.

[0017] This invention relates to the application of a low-stress pressure-sensitive adhesive for integrated composite molding of reflective films in the field of coating processes.

[0018] The low-stress pressure-sensitive adhesive for integrated composite molding of reflective film described in this invention can be applied to the surface of thermoplastic polyolefin waterproof membranes, fiberglass asphalt shingles, etc.

[0019] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention forms a core-shell structure stabilizer by combining a mesoporous silica nanocore with a flexible siloxane shell, enabling the pressure-sensitive adhesive to buffer shrinkage stress during curing and lamination, reducing warping, wrinkling, and localized delamination, which helps maintain the flatness and structural stability of the reflective film composite layer.

[0020] 2. The flexible, antioxidant, and stabilizing shell improves the dispersion of inorganic nanoparticles in organic adhesive systems, reduces particle agglomeration and interface defects, and makes the adhesive layer more continuous and uniform, thus exhibiting better initial tack, peel, and holding properties.

[0021] 3. The antioxidant components in the stabilizer can inhibit the oxidative degradation of the adhesive layer during outdoor thermo-oxidative and ultraviolet aging. The mesoporous nanostructure and flexible shell jointly maintain the stability of the adhesive layer interface. Therefore, the adhesion and reflective properties remain better after aging, making it suitable for long-term outdoor use of reflective films. Attached Figure Description

[0022] Figure 1 This is a TEM image of stabilizer 1 prepared in Preparation Example 1 of the present invention.

[0023] Figure 2 This is a SEM image of stabilizer 1 prepared in Preparation Example 1 of the present invention. Detailed Implementation

[0024] The following will provide a clear and complete description of the technical solutions of this invention. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0025] Preparation Example 1 Preparation of stabilizer 1: A1. Preparation of the core dispersion: 10.00 g of mesoporous silica nanospheres with an average particle size of 50 nm and a particle size distribution range of 45-55 nm were weighed and added to a 500 mL three-necked flask containing 200 mL of anhydrous ethanol. The three-necked flask was placed in an ice-water bath to maintain the system temperature at 0-5℃. The system was ultrasonically dispersed using a probe-type ultrasonic device at a frequency of 22 kHz, a power density of 0.6 W / mL, and a sonication time of 40 min. During sonication, there was a 1 min interval every 5 min to avoid localized temperature rise. After sonication, the mixture was stirred at 400 r / min for 15 min to obtain a milky white, homogeneous, and stable mesoporous silica core dispersion.

[0026] The mesoporous silica was purchased from Beijing Zhongke Keyou Technology Co., Ltd.

[0027] A2. Preparation of the trimethoxy-terminated polydimethylsiloxane and antioxidant 1010 composite: Weigh 6.00 g of trimethoxy-terminated polydimethylsiloxane and 1.50 g of antioxidant 1010, and add them to a beaker containing 60 mL of ethyl acetate; place the above mixture in a 45 °C water bath and stir at 300 r / min for 30 min until antioxidant 1010 is completely dissolved and mixed evenly with trimethoxy-terminated polydimethylsiloxane; then treat with an ultrasonic device with a frequency of 20 kHz and a power density of 0.4 W / mL for 10 min to obtain a clear or slightly milky white trimethoxy-terminated polydimethylsiloxane / antioxidant 1010 composite solution.

[0028] The trimethoxy-terminated polydimethylsiloxane is RH-FD20K trimethoxy-terminated polydimethylsiloxane, which was purchased from Zhejiang Runhe Organosilicon New Materials Co., Ltd.

[0029] A3. Grafting and Coating of a Flexible Antioxidant Stabilizing Shell: Under nitrogen protection, the mesoporous silica core dispersion obtained in A1 was heated to 68°C, and the stirring speed was controlled at 450 r / min. The trimethoxy-terminated polydimethylsiloxane / antioxidant 1010 composite solution obtained in A2 was added dropwise to the mesoporous silica core dispersion through a constant pressure dropping funnel, with the addition time controlled at 50 min. After the addition was completed, glacial acetic acid was added dropwise to the system to adjust the pH to 4.7, and then the reaction was carried out at 68°C with constant temperature stirring for 14 h to form an organic shell with both flexible buffering and antioxidant stabilizing effects.

[0030] A4. Phase Change Extraction and Drying: After the reaction, the reaction solution was allowed to cool naturally to 45°C and transferred to a high-pressure reactor. Supercritical carbon dioxide was then introduced for phase change extraction and drying. The extraction and drying pressure was controlled at 18 MPa, the temperature at 50°C, the carbon dioxide flow rate at 3 L / min, and the extraction and drying time at 3 h. After extraction, the pressure was slowly released to atmospheric pressure at a rate of 0.5 MPa / min, and the powder in the reactor was collected to obtain stabilizer 1.

[0031] Depend on Figure 1 As can be seen, the stabilizer 1 prepared in Preparation Example 1 of this invention exhibits a near-spherical nanoparticle morphology, with particle sizes mainly distributed in the range of 50-80 nm, which is basically consistent with the core size of the mesoporous silica nanospheres selected in the preparation process. A relatively uniform alternating light and dark texture can be observed inside the particles, indicating that the mesoporous silica core still maintains a certain mesoporous channel structure. Simultaneously, a coating layer with a relatively light contrast and soft boundary exists at the outer edge of the particles, indicating that an organic flexible shell layer has formed on the surface of the mesoporous silica. The particles in the figure show slight agglomeration, but no obvious large-scale aggregation or structural collapse, indicating that after supercritical carbon dioxide phase change extraction and drying, stabilizer 1 can maintain the nanosphere morphology and core-shell structure integrity well.

[0032] Depend on Figure 2 It is evident that stabilizer 1 is an aggregate of nanoparticles formed by the accumulation of numerous near-spherical particles. The particles are relatively uniform in size, and their surfaces exhibit a certain degree of roughness and granularity. This indicates that the organic shell coating did not completely smooth the particle surface, but rather formed a composite interface structure with some surface undulations. Local overlap and slight agglomeration exist between particles, which are common phenomena during the drying and sample preparation of nano-silica materials, but the overall structure still maintains a good spherical outline and dispersion. Figure 1 TEM results show that stabilizer 1 has a core-shell structure consisting of a mesoporous silica core and an organic flexible antioxidant shell. This structure is beneficial to improving its compatibility, dispersion stability and antioxidant stabilization effect in organic polymer systems.

[0033] Preparation Example 2 Stabilizer 2 was prepared by referring to the preparation method of Preparation Example 1, except that the amount of trimethoxy-terminated polydimethylsiloxane was replaced from 6.00 g to 7.00 g, the amount of antioxidant 1010 was replaced from 1.50 g to 1.80 g, and the pH of the system in A3 was replaced from 4.7 to 5.0. The rest remained the same as in Preparation Example 1, thus obtaining stabilizer 2.

[0034] Preparation Example 3 Stabilizer 3 was prepared by referring to the preparation method of Preparation Example 1, except that the supercritical carbon dioxide phase change extraction drying pressure in A4 was replaced from 18 MPa to 20 MPa, and the extraction drying time was replaced from 3 h to 4 h. The rest remained the same as in Preparation Example 1, and stabilizer 3 was obtained.

[0035] Preparation Example 4 Stabilizer 4 was prepared by referring to the preparation method of Preparation Example 1, except that the constant temperature stirring reaction temperature in A3 was replaced from 68°C to 65°C, and the constant temperature stirring reaction time was replaced from 14h to 12h. The rest was kept the same as in Preparation Example 1, and stabilizer 4 was obtained.

[0036] Comparative Preparation Example 1 Comparative stabilizer 1 was prepared by referring to the preparation method of preparation example 1, except that the "trimethoxy-terminated polydimethylsiloxane and antioxidant 1010 complex" was replaced with an equal mass of trimethoxy-terminated polydimethylsiloxane, and antioxidant 1010 was not added. The rest was the same as in preparation example 1, and comparative stabilizer 1 was obtained.

[0037] Comparative Preparation Example 2 Comparative stabilizer 2 was prepared by referring to the preparation method of preparation example 1, except that the "trimethoxy-terminated polydimethylsiloxane and antioxidant 1010 complex" was replaced with an equal mass of antioxidant 1010, and no trimethoxy-terminated polydimethylsiloxane was added. The rest was the same as in preparation example 1, and comparative stabilizer 2 was obtained.

[0038] Comparative preparation example 3 Comparative stabilizer 3 was prepared by referring to the preparation method of preparation example 1, but replacing the mesoporous silica nanospheres with an equal mass of ordinary nano silica, wherein the average particle size of the ordinary nano silica was 50 nm, and the rest remained the same as in preparation example 1, thus obtaining comparative stabilizer 3.

[0039] Ordinary nano silica was purchased from Hangzhou Hengge Nanotechnology Co., Ltd., HN-SP50.

[0040] Comparative preparation example 4 Comparative stabilizer 4 was prepared by referring to the preparation method of preparation example 1, but omitting the step of adjusting the pH with glacial acetic acid in A3, that is, not adjusting the pH of the system to 4.7, and keeping the rest the same as preparation example 1, thus obtaining comparative stabilizer 4.

[0041] Comparative preparation example 5 Comparative stabilizer 5 was prepared by referring to the preparation method of preparation example 1, except that the supercritical carbon dioxide phase change extraction drying of A4 was replaced by blast drying at 80°C for 6 hours, and the rest was the same as in preparation example 1, thus obtaining comparative stabilizer 5.

[0042] Example 1 This embodiment provides a low-stress pressure-sensitive adhesive composition and coating process for integrated composite molding of reflective films: 1. Raw material components by weight: Soft monomer: Isooctyl acrylate, 50 parts; Hard monomer: methyl methacrylate, 20 parts; Functional monomer: Hydroxyethyl acrylate, 5 parts; Stabilizer: 10 parts of stabilizer 1 prepared in Preparation Example 1; Initiator: Benzoyl peroxide, 2 parts; Solvent: Ethyl acetate, 22 parts; 2. Coating process: S1. Preparation of a low-stress pressure-sensitive adhesive for integrated composite molding of reflective films: S11. Take 50 parts of soft monomer, 20 parts of hard monomer, 5 parts of functional monomer and 22 parts of solvent, add them to a dry reaction vessel in sequence, turn on the stirrer and stir at room temperature for 18 minutes until all components are mixed evenly to obtain a uniform and transparent mixture. S12. Add 10 parts of stabilizer to the above reaction vessel, heat the system to 60°C, and continue stirring for 40 minutes until the stabilizer is evenly dispersed and the system is homogeneous. S13. Raise the temperature of the system in the reactor to 75°C, add 2 parts of initiator to the system, and carry out free radical copolymerization while maintaining stirring. During the reaction, adjust the stirring speed every 40 minutes to ensure uniform polymerization and avoid local gelation and stress concentration. After the reaction, cool the obtained prepolymer to 38°C, filter it to remove trace amounts of gel impurities, and obtain the low-stress pressure-sensitive adhesive for integrated composite molding of reflective film. S2. A coating process for a low-stress pressure-sensitive adhesive used in the integrated molding of reflective films: S21. Pretreatment: Take the microprism type reflective film PC substrate and perform surface corona treatment using a corona treatment machine. Control the corona treatment power to be 350W and the treatment time to be 4s to remove impurities and oil stains from the substrate surface and improve the adhesion of the substrate surface. S22. Coating: Using a comma-shaped doctor blade coating method, the low-stress pressure-sensitive adhesive prepared above is evenly coated on the surface of the pretreated reflective film substrate, and the coating speed is controlled at 2m / min. S23. Curing: The coated reflective film is sent into a tunnel-type drying and curing oven and a three-stage gradient temperature curing process is adopted. The first stage curing temperature is controlled at 85℃ and the curing time is 25s; the second stage curing temperature is controlled at 105℃ and the curing time is 35s; the third stage curing temperature is controlled at 75℃ and the curing time is 18s. S24. Composite molding: The cured reflective film is laminated with glassine release paper, and the lamination speed is kept consistent with the coating speed. After lamination, the product is allowed to cool naturally to room temperature, and the winding tension is controlled at 65N for winding. This yields the coating process of the low-stress pressure-sensitive adhesive used for integrated composite molding of reflective film.

[0043] Examples 2-4 In Examples 2-4, a low-stress pressure-sensitive adhesive for integrated composite molding of reflective film was prepared sequentially. The preparation method and coating process of Example 1 were used as references, except that the stabilizers were replaced with stabilizers 2-4 in sequence, and the rest were the same as in Example 1.

[0044] Comparative Examples 1-5 In Comparative Examples 1-5, a low-stress pressure-sensitive adhesive for integrated composite molding of reflective film was prepared sequentially. The preparation method and coating process of Example 1 were followed, but the stabilizers were replaced with comparative stabilizers 1-5 in sequence, and the rest were the same as in Example 1.

[0045] Performance testing: 1. Basic adhesion performance: Initial tack was tested according to GB / T4852-2002; holding power was tested according to GB / T4851-2020, with a load of 1kg and a test temperature of 25℃. The data are shown in Table 1.

[0046] 2. Weather resistance: Weather resistance was tested according to GB / T16422.3-2014: aging time 1000 hours, temperature 60℃, and after aging, the 180° peel strength retention rate and reflectivity retention rate were tested. The data are shown in Table 1.

[0047] Table 1

[0048] Table 1 shows that the examples using core-shell stabilizers outperformed the comparative examples in terms of initial adhesion, peel strength, holding power, and performance retention after aging. The flexible siloxane shell, antioxidant components, mesoporous silica core, and phase change extraction drying process work synergistically: the mesoporous silica core provides stable nano-support and interfacial anchoring points, which helps to suppress curing shrinkage and stress concentration of the adhesive layer; the flexible shell formed by trimethoxy-terminated polydimethylsiloxane improves the compatibility between the stabilizer and the acrylate matrix, making stress release more moderate, thereby maintaining good adhesion continuity and holding power stability; antioxidant 1010 gives the adhesive layer stronger resistance to heat and oxygen aging, reducing the attenuation of peel strength and reflectivity after aging. The differences between the examples indicate that moderately increasing the flexible shell and antioxidant components is beneficial for weather resistance, but excessive or insufficient reaction conditions will affect the interfacial balance. In the comparative examples, the lack of antioxidant components mainly resulted in a decrease in weather resistance, while the lack of flexible siloxanes resulted in insufficient compatibility and internal stress buffering. Ordinary silica, due to the lack of mesoporous structure, has weak interfacial bonding and dispersion stability. The failure to adjust acidic conditions will lead to insufficient hydrolysis and condensation of silanes, and forced-air drying is prone to particle agglomeration and pore structure destruction. Therefore, the overall performance shows a downward trend.

[0049] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A low-stress pressure-sensitive adhesive for integrated composite molding of reflective films, characterized in that, By weight, its formulation includes the following components: 45-55 parts of soft monomer, 17-23 parts of hard monomer, 4-6 parts of functional monomer, 8-12 parts of stabilizer, 1-2 parts of initiator, and 20-25 parts of solvent. The stabilizer is a core-shell structure stabilizer, which includes a mesoporous silica nanosphere core and a flexible antioxidant stabilizing shell coating the surface of the mesoporous silica nanosphere core. The flexible antioxidant stabilizing shell is composed of a complex formed by trimethoxy-terminated polydimethylsiloxane and antioxidant 1010.

2. The low-stress pressure-sensitive adhesive for integrated composite molding of reflective films according to claim 1, characterized in that, The soft monomer is any one of isooctyl acrylate and isobutyl acrylate, or a combination thereof.

3. The low-stress pressure-sensitive adhesive for integrated composite molding of reflective films according to claim 1, characterized in that, The hard monomer is any one of methyl methacrylate and ethyl methacrylate, or a combination thereof.

4. The low-stress pressure-sensitive adhesive for integrated composite molding of reflective films according to claim 1, characterized in that, The functional monomer is any one of hydroxyethyl acrylate and hydroxypropyl acrylate, or a combination thereof.

5. The low-stress pressure-sensitive adhesive for integrated composite molding of reflective films according to claim 1, characterized in that, The stabilizer is prepared by: A1. Preparation of the core dispersion: Weigh mesoporous silica nanospheres with an average particle size of 50 nm and a particle size distribution range of 45-55 nm, and add them to anhydrous ethanol, wherein 180-220 mL of anhydrous ethanol is added for every 10 g of mesoporous silica nanospheres; place the system under ice-water bath conditions for ultrasonic cavitation dispersion treatment, keep the system temperature at 0-5℃, the ultrasonic frequency at 20-25 kHz, the power density at 0.5-0.8 W / mL, and the ultrasonic time at 30-45 min; during the ultrasonic process, pause for 0.5-1.5 min every 4-6 min of ultrasonication, and after the ultrasonication is completed, continue stirring at a stirring speed of 300-500 r / min for 10-20 min to obtain the mesoporous silica core dispersion; A2. Preparation of the trimethoxy-terminated polydimethylsiloxane and antioxidant 1010 composite: Based on 100 parts by weight of the mesoporous silica nanospheres, weigh 55-70 parts by weight of trimethoxy-terminated polydimethylsiloxane and 12-18 parts by weight of antioxidant 1010, and add them to ethyl acetate, wherein 50-70 mL of ethyl acetate is added for every 10 g of mesoporous silica nanospheres; place the mixture at 40-50℃ and stir at 250-350 r / min for 20-40 min to dissolve and uniformly disperse antioxidant 1010 in the trimethoxy-terminated polydimethylsiloxane; then treat with an ultrasonic device at a frequency of 18-22 kHz and a power density of 0.3-0.5 W / mL for 8-15 min to obtain a trimethoxy-terminated polydimethylsiloxane / antioxidant 1010 composite solution; A3. Grafting and coating of a flexible antioxidant stabilizing shell: Under nitrogen protection, the mesoporous silica core dispersion obtained in A1 is heated to 65-70℃, and the stirring speed is controlled at 400-500 r / min; the trimethoxy-terminated polydimethylsiloxane / antioxidant 1010 composite solution obtained in A2 is added dropwise to the mesoporous silica core dispersion for 40-60 min; after the addition is completed, glacial acetic acid is added to adjust the pH of the system to 4.5-5.0, and the reaction is carried out at 65-70℃ with constant temperature stirring for 12-15 h, so that the trimethoxy-terminated polydimethylsiloxane and the silanol groups on the surface of the mesoporous silica undergo a hydrolysis and condensation reaction, and at the same time, the antioxidant 1010 is dispersed and fixed in the flexible shell formed by the trimethoxy-terminated polydimethylsiloxane, thus forming a flexible antioxidant stabilizing shell on the surface of the mesoporous silica nanospheres; A4. Phase change extraction and drying: After the reaction is completed, the reaction solution is cooled to 40-50℃ and transferred to a high-pressure reactor. Supercritical carbon dioxide fluid is introduced for phase change extraction and drying. The extraction and drying pressure is controlled at 15-20MPa, the temperature at 45-55℃, the carbon dioxide fluid flow rate at 2-4L / min, and the extraction and drying time at 2-4h. After extraction, the pressure is slowly released to atmospheric pressure at a rate of 0.3-0.8MPa / min, and the powder in the reactor is collected to obtain the stabilizer.

6. The low-stress pressure-sensitive adhesive for integrated composite molding of reflective films according to claim 1, characterized in that, The initiator is any one or a combination of benzoyl peroxide, dicumyl peroxide, and cumene peroxide.

7. The low-stress pressure-sensitive adhesive for integrated composite molding of reflective films according to claim 1, characterized in that, The solvent is any one of ethyl acetate, butyl acetate, or a combination thereof.

8. A coating process for a low-stress pressure-sensitive adhesive for integrated composite molding of reflective films, as described in any one of claims 1-7, characterized in that, Includes the following steps: S1. Preparation of a low-stress pressure-sensitive adhesive for integrated composite molding of reflective films: S11. Take the soft monomer, hard monomer, functional monomer and solvent, add them to the reaction vessel, stir for 15-20 minutes, mix evenly to obtain a mixture; S12. Add the stabilizer to the reactor, heat to 58-62℃, and continue stirring for 35-45 minutes until the stabilizer is evenly dispersed; S13. Raise the temperature of the reactor to 72-78℃, add the initiator, stir and react for 3-4 hours to obtain a prepolymer; cool the prepolymer to 35-40℃, filter, and obtain the low-stress pressure-sensitive adhesive for integrated composite molding of reflective film. S2. A coating process for a low-stress pressure-sensitive adhesive used in the integrated molding of reflective films: S21. Pretreatment: The reflective film substrate is subjected to corona treatment with a power of 300-400W for 3-5 seconds to remove impurities and oil stains from the substrate surface. S22. Coating: Using a doctor blade coating method, the low-stress pressure-sensitive adhesive is evenly coated on the surface of the pretreated reflective film substrate at a coating speed of 1.5-2.5 m / min. S23. Curing: The coated reflective film is sent into a drying and curing oven and cured in three stages. The first stage is at a temperature of 80-90℃ for 20-30 seconds; the second stage is at a temperature of 100-110℃ for 30-40 seconds; and the third stage is at a temperature of 70-80℃ for 15-20 seconds. S24. Composite molding: The cured reflective film is laminated with release paper, and after lamination, it is naturally cooled to room temperature. The film is then wound up to obtain the coating process of the low-stress pressure-sensitive adhesive used for integrated composite molding of reflective film.

9. The coating process for a low-stress pressure-sensitive adhesive used in the integrated composite molding of reflective films according to claim 8, characterized in that, During the S13 reaction, the stirring speed is adjusted every 40 minutes, with an adjustment range of 250-300 r / min.

10. The coating process for a low-stress pressure-sensitive adhesive used in the integrated composite molding of reflective films according to claim 8, characterized in that, During the S24 reaction process, the bonding speed and the coating speed are kept consistent.

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