Hydrolysis-resistant TPU (Thermoplastic Polyurethane) protective film and preparation method thereof

Abstract

The invention discloses a hydrolysis-resistant TPU polyurethane protective film and a preparation method thereof, and belongs to the technical field of TPU polyurethane protective films, the hydrolysis-resistant TPU polyurethane protective film comprises a first silicone rubber layer located on one side surface of the hydrolysis-resistant TPU polyurethane protective film; the second silicon rubber layer is positioned on the surface of the other side of the hydrolysis-resistant TPU polyurethane protective film; and the polyurethane layer is positioned between the first silicon rubber layer and the second silicon rubber layer with silanol on the surface. The high-temperature-resistant high-humidity acid-base-resistant plastic can resist hydrolysis and can be used in high-temperature, high-humidity and acid-base environments.

Description

Technical Field

[0001] The present invention relates to the technical field of polyurethane protective films, in particular to a hydrolysis-resistant TPU polyurethane protective film and a preparation method thereof. Background Art

[0002] The temperature resistance range of ordinary polyurethane films is usually between -60°C and 80°C. Within this temperature range, polyurethane can maintain good physical and chemical stability and will not easily deform or age. In a high-temperature environment, the performance of polyurethane films (such as tensile strength, tear strength, and oil resistance) will significantly decline. Therefore, polyurethane films are not suitable for long-term use in high-temperature environments. Polyurethane is prone to hydrolysis in a humid environment. A high-humidity environment provides sufficient moisture for the hydrolysis reaction and promotes the reaction. In a high-humidity environment, moisture is more likely to penetrate into the interior of the polyurethane material, resulting in a decline in overall performance. At high temperatures, the movement of polyurethane molecular chains intensifies, and moisture is more likely to penetrate into the material interior, expanding the scope of the hydrolysis reaction. Adding a hydrolysis-resistant agent, such as carbodiimide, inhibits the hydrolysis reaction of polyurethane in a humid environment. Although carbodiimide can significantly inhibit the hydrolysis reaction, the polyurethane material may still undergo a certain degree of hydrolysis under extreme conditions (such as high temperature, high humidity, and acid-base environment). Polyurethane films are relatively sensitive to ultraviolet light. Prolonged exposure to sunlight will cause material aging, color change, and performance decline. Therefore, in outdoor applications, additional protective treatments need to be carried out on polyurethane films, such as adding ultraviolet absorbers or using coating protection. For this reason, the present invention provides a hydrolysis-resistant TPU polyurethane protective film and a preparation method thereof. Summary of the Invention

[0003] In order to overcome the deficiencies of the prior art, one of the purposes of the present invention is to provide a hydrolysis-resistant TPU polyurethane protective film that can resist hydrolysis and can be used in high-temperature, high-humidity, and acid-base environments.

[0004] Another purpose of the present invention is to provide a production process for a hydrolysis-resistant TPU polyurethane protective film, which is simple to prepare and has a low cost.

[0005] One of the purposes of the present invention is achieved by adopting the following technical solution:

[0006] A hydrolysis-resistant TPU polyurethane protective film, comprising a first silicone rubber layer located on one side surface of the hydrolysis-resistant TPU polyurethane protective film; a second silicone rubber layer located on the other side surface of the hydrolysis-resistant TPU polyurethane protective film; a polyurethane layer located between the first silicone rubber layer and the second silicone rubber layer with silanol on the surface, and the polyurethane layer is in contact with the first silicone rubber layer and the second silicone rubber layer with silanol on the surface; both the first silicone rubber layer and the second silicone rubber layer with silanol on the surface contain 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified nano-silica and 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified hollow glass microspheres, and the 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified nano-silica and the 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified hollow glass microspheres are uniformly distributed in the silicone rubber layer.

[0007] Further, the particle size range of the 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified nano-silica is 1 - 100 nm, and the particle size range of the 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified hollow glass microspheres is 1 - 100 microns.

[0008] Further, the total content of the 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified nano-silica and the 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified hollow glass microspheres both account for 5% - 30% of the weight of the silicone rubber layer.

[0009] Further, the preparation method of the 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified nano-silica comprises the following steps:

[0010] S1. Dispersion of nano-SiO2: Use ultrasonic waves to disperse 2.5 g of the nano-SiO2 in 100 mL of an ethanol-water mixed solution with a volume ratio of 1:4, and the ultrasonic treatment time is 10 - 30 minutes;

[0011] S2. Add 4.0 mL of ammonia water to the ethanol-water mixed solution, then add 2 mL of 1H,1H,2H,2H-perfluorodecyltriethoxysilane to the ethanol-water mixed solution, and stir evenly to promote the hydrolysis reaction of 1H,1H,2H,2H-perfluorodecyltriethoxysilane. After hydrolysis, 1H,1H,2H,2H-perfluorodecyltriethoxysilane generates silanol groups (-Si(OH)3), and the silanol groups will undergo a condensation reaction with the hydroxyl groups on the surface of the nano-SiO2 to form silicon-oxygen bonds (Si-O-Si), thereby firmly grafting the perfluorodecyl chain of 1H,1H,2H,2H-perfluorodecyltriethoxysilane onto the surface of the nano-SiO2. The reaction mixture is stirred at 60 °C for 2 hours to ensure full reaction;

[0012] S3. Subsequently, centrifuge, wash, and dry at 70 °C for 24 hours to obtain the nano-silica modified with 1H,1H,2H,2H-perfluorodecyltriethoxysilane.

[0013] Furthermore, the preparation method of the 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified hollow glass microspheres includes the following steps:

[0014] S1. Treat the hollow glass microspheres with a 0.1 - 1.0 M sodium hydroxide solution to hydroxylate the surface of the hollow glass microspheres. The treatment time is 1 - 2 h. After treatment, wash the hollow glass microspheres with deionized water multiple times to remove the residual sodium hydroxide:

[0015] S2. Use ultrasonic waves to disperse 2.5 g of the hollow glass microspheres in 100 mL of an ethanol-water mixed solution with a volume ratio of 1:4. The ultrasonic treatment time is 10 - 30 minutes;

[0016] S3. Add 4.0 mL of ammonia water to the ethanol-water mixed solution, then add 2 mL of 1H,1H,2H,2H-perfluorodecyltriethoxysilane to the ethanol-water mixed solution, and stir evenly to promote the hydrolysis reaction of 1H,1H,2H,2H-perfluorodecyltriethoxysilane. After hydrolysis, 1H,1H,2H,2H-perfluorodecyltriethoxysilane generates silanol groups (-Si(OH)3), and the silanol groups will undergo a condensation reaction with the hydroxyl groups on the surface of the hollow glass microspheres to form silicon-oxygen bonds (Si-O-Si), thereby firmly grafting the perfluorodecyl chain of 1H,1H,2H,2H-perfluorodecyltriethoxysilane onto the surface of the hollow glass microspheres. The reaction mixture is stirred at 60 °C for 2 hours to ensure full reaction;

[0017] S4. Subsequently, centrifuge, wash, and dry at 70 °C for 24 hours to obtain the hollow glass microspheres modified with 1H,1H,2H,2H-perfluorodecyltriethoxysilane.

[0018] The preparation method of the first silicone rubber layer and the second silicone rubber layer with silanols on the surface includes the following steps:

[0019] S1. Disperse nanoparticles: First, uniformly disperse the 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified nano-silica and the 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified hollow glass microspheres in a silicone rubber matrix;

[0020] S2. Form the mixture obtained in step S1 into a sheet by calendering, and perform a curing treatment to form a modified silicone rubber.

[0021] The preparation method of the polyurethane layer includes the following steps: S1. Hydroxylation of hydrogen-containing MQ resin: Perform a hydrosilylation reaction on the hydrogen-containing MQ resin and allyl polyether under the action of a platinum catalyst to generate the hydroxy MQ resin (HO-MQ);

[0022] S2. Polyether modification: Further react the hydroxy MQ resin with a polyether polyol to introduce a polyether segment to form a polyether-modified MQ resin (E-MQ);

[0023] S3. Preparation of prepolymer: React polypropylene glycol (PPG) and diphenylmethane-4,4'-diisocyanate (MDI) to generate a prepolymer;

[0024] S4. Chain extension and curing: Add 1,4-butanediol (BDO) to the prepolymer, and use the 1,4-butanediol as a chain extender. At the same time, add the polyether-modified MQ resin (E-MQ) to form a cross-linked structure through urethane bonds;

[0025] S5. Mixing and curing: After uniformly mixing the prepolymer, the chain extender, and the polyether-modified MQ resin, perform a curing reaction to form the polyurethane layer.

[0026] The second object of the present invention is achieved by the following technical solution:

[0027] A preparation method of a hydrolysis-resistant TPU polyurethane protective film includes the following steps:

[0028] S1. Laminating: Cover the side of the polyurethane layer with the side of the first silicone rubber layer having silanols, and cover the other side of the polyurethane layer with the side of the second silicone rubber layer having silanols;

[0029] S2. Use a hot pressing device for lamination, control the hot pressing temperature at 120 - 140 °C, the pressure at 20 - 30 MPa, and the pressure holding time at 300 - 500 seconds to ensure tight bonding between layers.

[0030] S3. Cooling and shaping: After lamination, cool the material to room temperature to obtain the described hydrolysis - resistant TPU polyurethane protective film.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] (1) The present invention provides a hydrolysis - resistant TPU polyurethane protective film, which combines the advantages of silicone rubber and polyurethane. Polyurethane has a relatively high tensile strength but relatively poor flexibility. In applications that require high flexibility, polyurethane may be inferior to silicone rubber; while silicone rubber has relatively low tensile strength and tear resistance and is prone to breakage in an environment with high mechanical stress. Silicone rubber has good tolerance to most strong acids and strong bases at room temperature; silicone rubber has excellent high - and low - temperature resistance (-100 °C to 250 °C), while polyurethane performs well at room temperature. Therefore, the hydrolysis - resistant TPU polyurethane protective film can maintain good physical and chemical properties within the temperature range of -120 °C to 250 °C and can be used for a long time in a high - temperature environment.

[0033] Add fillers with low thermal conductivity (such as hollow glass microspheres, etc.) to silicone rubber, and use the low - thermal - conductivity characteristics of the fillers to reduce the thermal conductivity of silicone rubber. At the same time, nano - silica and hollow glass microspheres are modified with 1H,1H,2H,2H - perfluorodecyltriethoxysilane to enhance the interfacial bonding between the nanoparticles and hollow glass microspheres and silicone rubber and improve the dispersion of the nanoparticles and hollow glass microspheres in silicone rubber; polyurethane materials generally have good tolerance to alkaline environments because the ester bonds and ether bonds in polyurethane molecules are relatively stable under alkaline conditions. The first silicone rubber layer and the second silicone rubber layer are first treated with tetrahydrofuran solvent, and its polarity is used to insert into the space between the silicon - oxygen chains, breaking the hydrogen bonds between the silicon - oxygen chains that form silicone rubber and weakening the bond energy of the silicon - oxygen bond (Si - O - Si). After treatment with tetrahydrofuran solvent, and then treated with an alkali solution, the silicon - oxygen bond (Si - O - Si) is more likely to break, forming the first silicone rubber layer and the second silicone rubber layer with silanol on the surface. The side of the first silicone rubber layer and the second silicone rubber layer with silanol groups covers the polyurethane layer. Under the action of the alkali solution, the ethoxy groups (-OCH 2 CH 3 ) of 1H,1H,2H,2H - perfluorodecyltriethoxysilane on the surface of the first silicone rubber layer and the second silicone rubber layer are hydrolyzed to generate silanol (-Si(OH) 3) These hydroxyl groups can undergo chemical reactions with the isocyanate groups (-NCO) or urethane groups (-NHCOO-) in the polyurethane to form strong silicon-oxygen bonds (Si-O-Si). This chemical bonding significantly enhances the interfacial adhesion between 1H,2H,2H-perfluorodecyltriethoxysilane and the polyurethane, firmly bonding the first silicone rubber layer, the second silicone rubber layer, and the polyurethane layer. Using a modifier containing polar groups (such as polyether-modified MQ resin) can enhance the polarity of the soft segment of the polyurethane, further strengthening the firmness of the bond and preventing physical separation at the interface. This interfacial enhancement mechanism helps maintain the structural integrity of the hydrolysis-resistant TPU polyurethane protective film. 1H,1H,2H,2H-perfluorodecyltriethoxysilane has extremely strong 1H,1H,2H,2H-perfluorodecyl hydrophobicity, which can improve the hydrophobicity of the other side of the first silicone rubber layer and the second silicone rubber layer. The aging resistance and ultraviolet resistance of the silicone rubber layer significantly extend the service life of the hydrolysis-resistant TPU polyurethane protective film. Brief Description of the Drawings

[0034] To more clearly illustrate the embodiments of the present invention, the drawings required for the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the provided drawings.

[0035] Figure 1 It is a result diagram of FT-IR spectroscopy detecting the changes in the characteristic absorption peak intensities of the silanol groups and the characteristic absorption peak intensities of the silicon-oxygen bond (Si-O-Si) in the first silicone rubber layer and the second silicone rubber layer in Example 1, respectively. Detailed Embodiments

[0036] The following further describes the present invention in combination with specific embodiments. It should be noted that, on the premise of no conflict, the following-described embodiments or technical features can be arbitrarily combined to form new embodiments.

[0037] Silica nanoparticles and 1H,1H,2H,2H-perfluorodecyltriethoxysilane (PFDTES, 97%) were provided by Shanghai Macklin Biochemical Co., Ltd.

[0038] Methyl vinyl silicone rubber, molecular weight: generally between 45,000 and 70,000, vinyl content: 0.07% - 0.30% (mole fraction), purchased from Dongguan Lansil Silicone Rubber Technology Co., Ltd., Sinopharm Chemical Reagent Co., Ltd.

[0039] Hollow glass microspheres were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0040] Hydrogen-containing MQ resin was purchased from Jiaxing United Chemical Co., Ltd.

[0041] Polypropylene glycol (PPG): As a polyether polyol, its molecular weight is usually between 800 and 2000, with good flexibility and water resistance, CAS: 25322-69-4, purchased from Kandisi Chemical Industry (Hubei) Co., Ltd.

[0042] Polytetrahydrofuran glycol (PTMG): As a polyether polyol, its molecular weight is between 400 and 4000, with excellent low-temperature resistance and mechanical properties, CAS: 25190-06-1, purchased from Hebei Mojin Biotechnology Co., Ltd.

[0043] Polypropylene glycol triol: As a polyether polyol, it is synthesized from glycerol triol initiator, has multiple hydroxyl groups, and can be used to prepare crosslinked polyurethane polypropylene glycol triol, CAS: 25322-69-4, purchased from Kandisi Chemical Industry (Hubei) Co., Ltd.;

[0044] Diphenylmethane - 4,4'-diisocyanate (MDI), CAS: 101-68-8, purchased from Nantong Runfeng Petrochemical Co., Ltd.;

[0045] 1,4-Butanediol, CAS: 110-63-4, purchased from Qianyan Chemical Technology (Wuhan) Co., Ltd.

[0046] Example 1

[0047] This example provides a hydrolysis-resistant TPU polyurethane protective film, including a first silicone rubber layer located on one surface of the hydrolysis-resistant TPU polyurethane protective film; a second silicone rubber layer located on the other surface of the hydrolysis-resistant TPU polyurethane protective film; a polyurethane layer located between the first silicone rubber layer and the second silicone rubber layer, and the polyurethane layer is in contact with the first silicone rubber layer and the second silicone rubber layer; both the first silicone rubber layer and the second silicone rubber layer contain 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified nano-silica and 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified hollow glass microspheres, and the 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified nano-silica and 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified hollow glass microspheres are uniformly distributed in the silicone rubber layer.

[0048] In this example, the particle size range of 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified nano-silica is 65 nm, and the particle size range of 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified hollow glass microspheres is 72 microns.

[0049] In this embodiment, the total content of 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified nano-silica and 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified hollow glass microspheres both account for 18% of the weight of the silicone rubber layer.

[0050] In this embodiment, the preparation method of 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified nano-silica comprises the following steps:

[0051] S1. Dispersion of nano-SiO 2 : Use ultrasonic waves to disperse 2.5 g of nano-SiO 2 in 100 mL of an ethanol-water mixed solution with a volume ratio of 1:4, and the ultrasonic treatment time is 10 - 30 minutes;

[0052] S2. Add 4.0 mL of ammonia water to the ethanol-water mixed solution, then add 2 mL of 1H,1H,2H,2H-perfluorodecyltriethoxysilane to the ethanol-water mixed solution, and stir evenly to promote the hydrolysis reaction of 1H,1H,2H,2H-perfluorodecyltriethoxysilane. After hydrolysis, 1H,1H,2H,2H-perfluorodecyltriethoxysilane generates silanol groups (-Si(OH) 3 ), and the silanol groups will undergo a condensation reaction with the hydroxyl groups on the surface of nano-SiO 2 to form siloxane bonds (Si-O-Si), thereby firmly grafting the perfluorodecyl chain of 1H,1H,2H,2H-perfluorodecyltriethoxysilane onto the surface of nano-SiO 2 . Stir the reaction mixture at 60 °C for 2 hours to ensure full reaction;

[0053] S3. Subsequently, centrifuge, wash, and dry at 70 °C for 24 hours to obtain 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified nano-silica.

[0054] In this embodiment, the preparation method of 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified hollow glass microspheres comprises the following steps:

[0055] S1. Treat the hollow glass microspheres with a 0.1 M sodium hydroxide solution to hydroxylate the surface of the hollow glass microspheres. The treatment time is 2 h. After treatment, wash the hollow glass microspheres with deionized water multiple times to remove the residual sodium hydroxide:

[0056] S2. Use ultrasonic waves to disperse 2.5 g of hollow glass microspheres in 100 mL of an ethanol-water mixed solution with a volume ratio of 1:4, and the ultrasonic treatment time is 10 minutes;

[0057] S3. Add 4.0 mL of ammonia water to the ethanol-water mixed solution, then add 2 mL of 1H,1H,2H,2H-perfluorodecyltriethoxysilane to the ethanol-water mixed solution, and stir evenly to promote the hydrolysis reaction of 1H,1H,2H,2H-perfluorodecyltriethoxysilane. After hydrolysis, 1H,1H,2H,2H-perfluorodecyltriethoxysilane generates silanol groups (-Si(OH) 3 ), and the silanol groups will undergo a condensation reaction with the hydroxyl groups on the surface of the hollow glass microspheres to form siloxane bonds (Si-O-Si), thereby firmly grafting the perfluorodecyl chain of 1H,1H,2H,2H-perfluorodecyltriethoxysilane to the surface of the hollow glass microspheres. The reaction mixture is stirred at 60 °C for 2 hours to ensure that the reaction proceeds fully;

[0058] S4. Subsequently, centrifuge, wash, and dry at 70 °C for 24 hours to obtain hollow glass microspheres modified with 1H,1H,2H,2H-perfluorodecyltriethoxysilane.

[0059] In this embodiment, the preparation methods of the first silicone rubber layer and the second silicone rubber layer include the following steps:

[0060] S1. Disperse nanoparticles: First, uniformly disperse 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified nano-silica and 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified hollow glass microspheres in the silicone rubber matrix methyl vinyl silicone rubber;

[0061] S2. Form the mixture in step S1 into a sheet by calendering process, and carry out curing treatment to form a modified silicone rubber. Treat one side of the modified silicone rubber with tetrahydrofuran solvent first, and after treatment, treat it with lye sodium hydroxide to form the first silicone rubber layer and the second silicone rubber layer with silanol on the surface.

[0062] In this embodiment, the preparation method of the polyurethane layer includes the following steps: S1. Hydroxylation of hydrogen-containing MQ resin: Carry out a hydrosilylation reaction of the hydrogen-containing MQ resin and allyl polyether under the action of a platinum catalyst to generate a hydroxyl MQ resin (HO-MQ);

[0063] S2. Polyether modification: Further react the hydroxyl MQ resin with polyether polyol polypropylene glycol (PPG) to introduce polyether segments to form a polyether-modified MQ resin (E-MQ);

[0064] S3. Preparation of prepolymer: React polypropylene glycol (PPG) and diphenylmethane-4,4'-diisocyanate (MDI) to generate a prepolymer;

[0065] S4. Chain extension and curing: Add 1,4 - butanediol (BDO) to the prepolymer. 1,4 - butanediol serves as a chain extender, and at the same time, add polyether - modified MQ resin (E - MQ). A cross - linked structure is formed through urethane bonds.

[0066] S5. Mixing and curing: After uniformly mixing the prepolymer, the chain extender, and the polyether - modified MQ resin, carry out a curing reaction to form a polyurethane layer.

[0067] This embodiment also provides a preparation method of a hydrolysis - resistant TPU polyurethane protective film, including the following steps:

[0068] S1. Laminating: Cover one side of the polyurethane layer with the side of the first silicone rubber layer having silanol on its surface, and cover the other side of the polyurethane layer with the side of the second silicone rubber layer having silanol on its surface;

[0069] S2. Use a hot - pressing device for laminating, control the hot - pressing temperature at 135 °C, the pressure at 20 MPa, and the pressure - holding time at 300 seconds to ensure tight bonding between layers;

[0070] S3. Cooling and shaping: After laminating is completed, cool the material to room temperature to obtain a hydrolysis - resistant TPU polyurethane protective film.

[0071] Example 2

[0072] This embodiment provides a hydrolysis - resistant TPU polyurethane protective film, including a first silicone rubber layer located on one side surface of the hydrolysis - resistant TPU polyurethane protective film; a second silicone rubber layer located on the other side surface of the hydrolysis - resistant TPU polyurethane protective film; a polyurethane layer located between the first silicone rubber layer and the second silicone rubber layer, and the polyurethane layer is in contact with the first silicone rubber layer and the second silicone rubber layer; both the first silicone rubber layer and the second silicone rubber layer contain 1H,1H,2H,2H - perfluorodecyltriethoxysilane - modified nano - silica and 1H,1H,2H,2H - perfluorodecyltriethoxysilane - modified hollow glass microspheres, and the 1H,1H,2H,2H - perfluorodecyltriethoxysilane - modified nano - silica and 1H,1H,2H,2H - perfluorodecyltriethoxysilane - modified hollow glass microspheres are uniformly distributed in the silicone rubber layer.

[0073] In this embodiment, the particle size range of the 1H,1H,2H,2H - perfluorodecyltriethoxysilane - modified nano - silica is 1 nm, and the particle size range of the 1H,1H,2H,2H - perfluorodecyltriethoxysilane - modified hollow glass microspheres is 100 microns.

[0074] In this embodiment, the total content of 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified nano-silica and 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified hollow glass microspheres both account for 30% of the weight of the silicone rubber layer.

[0075] In this embodiment, the preparation method of 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified nano-silica includes the following steps:

[0076] S1. Dispersion of nano-SiO 2 : Use ultrasonic waves to disperse 2.5 g of nano-SiO 2 in 100 mL of an ethanol-water mixed solution with a volume ratio of 1:4, and the ultrasonic treatment time is 20 minutes;

[0077] S2. Add 4.0 mL of ammonia water to the ethanol-water mixed solution, then add 2 mL of 1H,1H,2H,2H-perfluorodecyltriethoxysilane to the ethanol-water mixed solution, and stir evenly to promote the hydrolysis reaction of 1H,1H,2H,2H-perfluorodecyltriethoxysilane. After hydrolysis, 1H,1H,2H,2H-perfluorodecyltriethoxysilane generates silanol groups (-Si(OH) 3 ), and the silanol groups will undergo a condensation reaction with the hydroxyl groups on the surface of nano-SiO 2 to form a silicon-oxygen bond (Si-O-Si), thereby firmly grafting the perfluorodecyl chain of 1H,1H,2H,2H-perfluorodecyltriethoxysilane to the surface of nano-SiO 2 . The reaction mixture is stirred at 60 °C for 2 hours to ensure full reaction;

[0078] S3. Subsequently, centrifuge, wash, and dry at 70 °C for 24 hours to obtain 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified nano-silica.

[0079] In this embodiment, the preparation method of 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified hollow glass microspheres includes the following steps:

[0080] S1. Treat the hollow glass microspheres with a 0.6 M sodium hydroxide solution to hydroxylate the surface of the hollow glass microspheres. The treatment time is 1 h. After treatment, wash the hollow glass microspheres with deionized water multiple times to remove the residual sodium hydroxide:

[0081] S2. Use ultrasonic waves to disperse 2.5 g of hollow glass microspheres in 100 mL of an ethanol-water mixed solution with a volume ratio of 1:4, and the ultrasonic treatment time is 20 minutes;

[0082] S3. Add 4.0 mL of ammonia water to the ethanol-water mixed solution, then add 2 mL of 1H,1H,2H,2H-perfluorodecyltriethoxysilane to the ethanol-water mixed solution, and stir evenly to promote the hydrolysis reaction of 1H,1H,2H,2H-perfluorodecyltriethoxysilane. After hydrolysis, 1H,1H,2H,2H-perfluorodecyltriethoxysilane generates silanol groups (-Si(OH) 3 ), and the silanol groups will undergo a condensation reaction with the hydroxyl groups on the surface of the hollow glass microspheres to form silicon-oxygen bonds (Si-O-Si), thereby firmly grafting the perfluorodecyl chain of 1H,1H,2H,2H-perfluorodecyltriethoxysilane to the surface of the hollow glass microspheres. The reaction mixture is stirred at 60 °C for 2 hours to ensure that the reaction proceeds fully;

[0083] S4. Subsequently, centrifuge, wash, and dry at 70 °C for 24 hours to obtain hollow glass microspheres modified with 1H,1H,2H,2H-perfluorodecyltriethoxysilane.

[0084] In this embodiment, the preparation methods of the first silicone rubber layer and the second silicone rubber layer include the following steps:

[0085] S1. Disperse nanoparticles: First, uniformly disperse 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified nano-silica and 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified hollow glass microspheres in the silicone rubber matrix methyl vinyl silicone rubber;

[0086] S2. Form the mixture in step S1 into a sheet by calendering, and carry out curing treatment to form a modified silicone rubber. Treat one side of the modified silicone rubber with tetrahydrofuran solvent first, and then treat it with lye sodium hydroxide to form the first silicone rubber layer and the second silicone rubber layer with silanol on the surface.

[0087] In this embodiment, the preparation method of the polyurethane layer includes the following steps: S1. Hydroxylation of hydrogen-containing MQ resin: Carry out a hydrosilylation reaction of the hydrogen-containing MQ resin and allyl polyether under the action of a platinum catalyst to generate a hydroxyl MQ resin (HO-MQ);

[0088] S2. Polyether modification: Further react the hydroxyl MQ resin with polyether polyol polytetrahydrofuran diol (PTMG) to introduce a polyether chain segment to form a polyether-modified MQ resin (E-MQ);

[0089] S3. Preparation of prepolymer: React polypropylene glycol (PPG) and diphenylmethane-4,4'-diisocyanate (MDI) to generate a prepolymer, which is the soft segment of the polyurethane;

[0090] S4. Chain extension and curing: Add 1,4 - butanediol (BDO) to the prepolymer. 1,4 - butanediol serves as a chain extender. At the same time, add polyether - modified MQ resin (E - MQ). A cross - linked structure is formed through urethane bonds, which is the hard segment of the polyurethane.

[0091] S5. Mixing and curing: After uniformly mixing the prepolymer, chain extender, and polyether - modified MQ resin, carry out a curing reaction to form a polyurethane layer.

[0092] This embodiment also provides a preparation method of a hydrolysis - resistant TPU polyurethane protective film, including the following steps:

[0093] S1. Laminating: Cover one side of the polyurethane layer with the side of the first silicone rubber layer with silanol, and cover the other side of the polyurethane layer with the side of the second silicone rubber layer with silanol.

[0094] S2. Use a hot - pressing device for laminating, control the hot - pressing temperature at 120 °C, pressure at 25 MPa, and holding time at 400 seconds to ensure tight bonding between layers.

[0095] S3. Cooling and shaping: After laminating, cool the material to room temperature to obtain a hydrolysis - resistant TPU polyurethane protective film.

[0096] Example 3

[0097] This embodiment provides a hydrolysis - resistant TPU polyurethane protective film, including a first silicone rubber layer located on one side surface of the hydrolysis - resistant TPU polyurethane protective film; a second silicone rubber layer located on the other side surface of the hydrolysis - resistant TPU polyurethane protective film; a polyurethane layer located between the first silicone rubber layer and the second silicone rubber layer, and the polyurethane layer is in contact with the first silicone rubber layer and the second silicone rubber layer; both the first silicone rubber layer and the second silicone rubber layer contain 1H,1H,2H,2H - perfluorodecyltriethoxysilane - modified nano - silica and 1H,1H,2H,2H - perfluorodecyltriethoxysilane - modified hollow glass microspheres, and the 1H,1H,2H,2H - perfluorodecyltriethoxysilane - modified nano - silica and 1H,1H,2H,2H - perfluorodecyltriethoxysilane - modified hollow glass microspheres are evenly distributed in the silicone rubber layer.

[0098] In this embodiment, the particle size range of the 1H,1H,2H,2H - perfluorodecyltriethoxysilane - modified nano - silica is 100 nm, and the particle size range of the 1H,1H,2H,2H - perfluorodecyltriethoxysilane - modified hollow glass microspheres is 100 microns.

[0099] In this embodiment, the total content of 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified nano-silica and 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified hollow glass microspheres both account for 5% of the weight of the silicone rubber layer.

[0100] In this embodiment, the preparation method of 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified nano-silica comprises the following steps:

[0101] S1. Dispersion of nano-SiO 2 : Use ultrasonic waves to disperse 2.5 g of nano-SiO 2 in 100 mL of an ethanol-water mixed solution with a volume ratio of 1:4, and the ultrasonic treatment time is 30 minutes;

[0102] S2. Add 4.0 mL of ammonia water to the ethanol-water mixed solution, then add 2 mL of 1H,1H,2H,2H-perfluorodecyltriethoxysilane to the ethanol-water mixed solution, and stir evenly to promote the hydrolysis reaction of 1H,1H,2H,2H-perfluorodecyltriethoxysilane. After hydrolysis, 1H,1H,2H,2H-perfluorodecyltriethoxysilane generates silanol groups (-Si(OH) 3 ). The silanol groups will undergo a condensation reaction with the hydroxyl groups on the surface of nano-SiO 2 to form silicon-oxygen bonds (Si-O-Si), thereby firmly grafting the perfluorodecyl chain of 1H,1H,2H,2H-perfluorodecyltriethoxysilane onto the surface of nano-SiO 2 . The reaction mixture is stirred at 60 °C for 2 hours to ensure that the reaction proceeds fully;

[0103] S3. Subsequently, centrifuge, wash, and dry at 70 °C for 24 hours to obtain 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified nano-silica.

[0104] In this embodiment, the preparation method of 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified hollow glass microspheres comprises the following steps:

[0105] S1. Treat the hollow glass microspheres with a 1.0 M sodium hydroxide solution to hydroxylate the surface of the hollow glass microspheres. The treatment time is 1.5 h. After treatment, wash the hollow glass microspheres with deionized water multiple times to remove the residual sodium hydroxide:

[0106] S2. Use ultrasonic waves to disperse 2.5 g of hollow glass microspheres in 100 mL of an ethanol-water mixed solution with a volume ratio of 1:4, and the ultrasonic treatment time is 10 - 30 minutes;

[0107] S3. Add 4.0 mL of ammonia water to the ethanol-water mixed solution, then add 2 mL of 1H,1H,2H,2H-perfluorodecyltriethoxysilane to the ethanol-water mixed solution, and stir evenly to promote the hydrolysis reaction of 1H,1H,2H,2H-perfluorodecyltriethoxysilane. After hydrolysis, 1H,1H,2H,2H-perfluorodecyltriethoxysilane generates silanol groups (-Si(OH) 3 ), and the silanol groups will undergo a condensation reaction with the hydroxyl groups on the surface of the hollow glass microspheres to form silicon-oxygen bonds (Si-O-Si), thereby firmly grafting the perfluorodecyl chain of 1H,1H,2H,2H-perfluorodecyltriethoxysilane onto the surface of the hollow glass microspheres. The reaction mixture is stirred at 60 °C for 2 hours to ensure that the reaction proceeds fully;

[0108] S4. Subsequently, centrifuge, wash, and dry at 70 °C for 24 hours to obtain 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified hollow glass microspheres.

[0109] In this embodiment, the preparation methods of the first silicone rubber layer and the second silicone rubber layer include the following steps:

[0110] S1. Disperse nanoparticles: First, uniformly disperse 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified nano-silica and 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified hollow glass microspheres in the silicone rubber matrix methyl vinyl silicone rubber;

[0111] S2. Form the mixture in step S1 into a sheet by calendering, and carry out curing treatment to form a modified silicone rubber. First, treat one side of the modified silicone rubber with tetrahydrofuran solvent, and after treatment, treat it with lye sodium hydroxide to form the first silicone rubber layer and the second silicone rubber layer with silanol on the surface.

[0112] In this embodiment, the preparation method of the polyurethane layer includes the following steps: S1. Hydroxylation of hydrogen-containing MQ resin: Carry out a hydrosilylation reaction of the hydrogen-containing MQ resin and allyl polyether under the action of a platinum catalyst to generate a hydroxyl MQ resin (HO-MQ);

[0113] S2. Polyether modification: Further react the hydroxyl MQ resin with polyether polyol polyoxypropylene triol to introduce a polyether segment to form a polyether-modified MQ resin (E-MQ);

[0114] S3. Preparation of prepolymer: React polyoxypropylene glycol (PPG) and diphenylmethane-4,4'-diisocyanate (MDI) to generate a prepolymer;

[0115] S4, Chain Extension and Curing: Add 1,4-butanediol (BDO) to the prepolymer. 1,4-butanediol serves as a chain extender. Meanwhile, add polyether-modified MQ resin (E-MQ) and form a cross-linked structure through urethane bonds.

[0116] S5, Mixing and Curing: After uniformly mixing the prepolymer, chain extender, and polyether-modified MQ resin, conduct a curing reaction to form a polyurethane layer.

[0117] This embodiment also provides a method for preparing a hydrolysis-resistant TPU polyurethane protective film, including the following steps:

[0118] S1, Laminating: Cover one side of the polyurethane layer with the side of the first silicone rubber layer having silanol on its surface, and cover the other side of the polyurethane layer with the side of the second silicone rubber layer having silanol on its surface.

[0119] S2, Use a hot pressing device for lamination, control the hot pressing temperature at 140 °C, pressure at 30 MPa, and holding pressure time at 500 seconds to ensure tight bonding between layers.

[0120] S3, Cooling and Shaping: After lamination is completed, cool the material to room temperature to obtain a hydrolysis-resistant TPU polyurethane protective film.

[0121] Experimental Example

[0122] Fourier Transform Infrared Spectroscopy (FT-IR) Analysis: Before and after treatment with tetrahydrofuran solvent and alkaline solution, respectively detect the change in the characteristic absorption peak intensity of the silanol group and the change in the characteristic absorption peak intensity of the silicon-oxygen bond (Si-O-Si) in the first silicone rubber layer and the second silicone rubber layer in Example 1 through FT-IR spectra to verify the influence of solvation on the bond strength. By detecting the change in the characteristic absorption peak intensity of the silicon-oxygen bond (Si-O-Si) at approximately 1000 - 1200 cm -1 it is possible to confirm the cleavage of the silicon-oxygen bond; while the characteristic absorption peak of the silanol group will appear in the region of 3200 - 3600 cm -1 (O-H stretching vibration) and 1000 - 1100 cm -1 (Si-O stretching vibration) region, and the results are as Figure 1 shown.

[0123] As can be seen from Figure 1 , the blue curve (untreated sample) has an obvious characteristic absorption peak of the silicon-oxygen bond at 1000 - 1200 cm -1 , the red curve (treated sample) has a broad peak at 3200 - 3600 cm -1 , which is the characteristic absorption peak of the silanol group, and the characteristic absorption peak at 1000 - 1200 cm -1 weakens, indicating that the surfaces of the first silicone rubber layer and the second silicone rubber layer carry silanol groups.

Claims

1. A hydrolysis-resistant TPU polyurethane protective film, characterized in that: It comprises a first silicone rubber layer, which is located on one side of the hydrolysis-resistant TPU polyurethane protective film; a second silicone rubber layer, which is located on the other side of the hydrolysis-resistant TPU polyurethane protective film; a polyurethane layer, which is located between the first silicone rubber layer and the second silicone rubber layer with silanol on the surface, and the polyurethane layer is in contact with the first silicone rubber layer and the second silicone rubber layer with silanol on the surface; The first silicone rubber layer and the second silicone rubber layer with silanol on the surface both contain 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified nano-silica and 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified hollow glass microspheres, and the 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified nano-silica and the 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified hollow glass microspheres are uniformly distributed in the silicone rubber layer.

2. The hydrolysis-resistant TPU polyurethane protective film according to claim 1, characterized in that: The particle size of the nano-silica modified by 1H,1H,2H,2H-perfluorodecyltriethoxysilane is in the range of 1 to 100 nm, and the particle size of the hollow glass microspheres modified by 1H,1H,2H,2H-perfluorodecyltriethoxysilane is in the range of 1 to 100 microns.

3. The hydrolysis-resistant TPU polyurethane protective film according to claim 1, characterized in that: The total content of the nano silicon dioxide modified by 1H,1H,2H,2H-perfluorodecyltriethoxysilane and the hollow glass microspheres modified by 1H,1H,2H,2H-perfluorodecyltriethoxysilane both accounts for 5% to 30% of the weight of the silicone rubber layer.

4. The hydrolysis-resistant TPU polyurethane protective film according to claim 1, characterized in that: The preparation method of the 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified nano-silica comprises the following steps: S1. Dispersion of nano-SiO2: Use ultrasound to disperse 2.5 g of the nano-SiO2 in 100 mL of a mixed solution of ethanol and water with a volume ratio of 1:4, and the ultrasonic treatment time is 10-30 minutes; S2, adding 4.0mL of ammonia water to the ethanol-water mixed solution, and then adding 2mL of 1H,1H,2H,2H-perfluorodecyltriethoxysilane to the ethanol-water mixed solution, and stirring evenly to promote the hydrolysis reaction of the 1H,1H,2H,2H-perfluorodecyltriethoxysilane. The 1H,1H,2H,2H-perfluorodecyltriethoxysilane generates silanol groups after hydrolysis. The silanol groups react with the hydroxyl groups on the surface of the nano-SiO2 to form silicon-oxygen bonds, thereby firmly grafting the perfluorodecyl chains of the 1H,1H,2H,2H-perfluorodecyltriethoxysilane to the surface of the nano-SiO2. The reaction mixture is stirred at 60°C for 2 hours to ensure that the reaction is fully carried out; S3, then centrifuging, washing and drying at 70° C. for 24 hours to obtain the 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified nano-silica.

5. The hydrolysis-resistant TPU polyurethane protective film according to claim 1, characterized in that: The preparation method of the hollow glass microspheres modified by 1H,1H,2H,2H-perfluorodecyltriethoxysilane comprises the following steps: S1. Treating the hollow glass microspheres with a 0.1-1.0M sodium hydroxide solution can hydroxylate the surface of the hollow glass microspheres for 1-2 hours. After the treatment, the hollow glass microspheres are washed with deionized water for multiple times to remove the residual sodium hydroxide. S2, using ultrasound to disperse 2.5 g of the hollow glass microspheres in 100 mL of a mixed solution of ethanol and water with a volume ratio of 1:4, and the ultrasonic treatment time is 10-30 minutes; S3, adding 4.0 mL of ammonia water to the ethanol-water mixed solution, and then adding 2 mL of 1H,1H,2H,2H-perfluorodecyltriethoxysilane to the ethanol-water mixed solution, and stirring evenly to promote the hydrolysis reaction of the 1H,1H,2H,2H-perfluorodecyltriethoxysilane. The 1H,1H,2H,2H-perfluorodecyltriethoxysilane generates silanol groups after hydrolysis. The silanol groups react with the hydroxyl groups on the surface of the hollow glass microspheres to form silicon-oxygen bonds, thereby firmly grafting the perfluorodecyl chains of the 1H,1H,2H,2H-perfluorodecyltriethoxysilane to the surface of the hollow glass microspheres. The reaction mixture is stirred at 60° C. for 2 hours to ensure that the reaction is fully carried out; S4. Subsequently, the mixture was centrifuged at 70° C., washed and dried for 24 hours to obtain the 1H,1H,2H,2H-perfluorodecyltriethoxysilane-modified hollow glass microspheres.

6. The hydrolysis-resistant TPU polyurethane protective film according to claim 1, characterized in that: The method for preparing the first silicone rubber layer and the second silicone rubber layer having silanol on the surface comprises the following steps: S1. Dispersing nanoparticles: firstly, uniformly dispersing the nano-silica modified by 1H,1H,2H,2H-perfluorodecyltriethoxysilane and the hollow glass microspheres modified by 1H,1H,2H,2H-perfluorodecyltriethoxysilane in a silicone rubber matrix; S2, forming the mixture of step S1 into a sheet by a calendering process, and curing it to form a modified silicone rubber, and treating one side of the modified silicone rubber with a tetrahydrofuran solvent, and then treating it with an alkali solution to form the first silicone rubber layer and the second silicone rubber layer with silanol on the surface.

7. The hydrolysis-resistant TPU polyurethane protective film according to claim 1, characterized in that: The preparation method of the polyurethane layer comprises the following steps: S1. Hydroxylation of hydrogenated MQ resin: subjecting hydrogenated MQ resin to hydrosilylation reaction with allyl polyether under the action of platinum catalyst to generate the hydroxylated MQ resin; S2, polyether modification: further reacting the hydroxy MQ resin with a polyether polyol to introduce a polyether segment to form a polyether-modified MQ resin; S3, preparation of prepolymer: using polyoxypropylene glycol and diphenylmethane-4,4'-diisocyanate to react to generate a prepolymer; S4, chain extension and curing: adding 1,4-butanediol to the prepolymer, the 1,4-butanediol serving as a chain extender, and adding the polyether-modified MQ resin to form a cross-linked structure through urethane bonds; S5, mixing and curing: after the prepolymer, the chain extender and the polyether-modified MQ resin are uniformly mixed, a curing reaction is performed to form the polyurethane layer.

8. The method for preparing a hydrolysis-resistant TPU polyurethane protective film according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1, lamination: covering one side of the first silicone rubber layer with silanol on one side of the polyurethane layer, and covering the other side of the second silicone rubber layer with silanol on the other side of the polyurethane layer; S2. Use hot pressing equipment for lamination, control the hot pressing temperature to 120-140°C, the pressure to 20-30MPa and the holding time to 300-500 seconds to ensure close bonding between the layers; S3, cooling and shaping: After lamination is completed, the material is cooled to room temperature to obtain the hydrolysis-resistant TPU polyurethane protective film.

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