Ultraviolet aging resistant anti-drag film and preparation process thereof

Abstract

The invention relates to the technical field of anti-drag films, and particularly discloses an ultraviolet aging resistant anti-drag film and a preparation process thereof.A hindered amine light stabilizer HALs and a silane coupling agent KH-560 are introduced into substrate TPU resin, the strength, heat resistance and aging resistance of the material are enhanced, then an adhesive layer is formed on a substrate film, and the anti-drag film is prepared. A disulfide bond in the adhesive layer has a reversible fracture-self-repairing function, the fatigue resistance of the material is enhanced, the long-term service life of the material is prolonged, the surface layer is acrylic resin formed through copolymerization, the structure comprises a flexible alkyl chain and a siloxane chain segment, a microstructure is formed through hot rolling, the aerodynamic performance is optimized, and the purpose of reducing frictional resistance is achieved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of drag reduction film, in particular to a drag reduction film resistant to ultraviolet aging and a preparation process thereof. BACKGROUND

[0002] The drag reduction film is a composite film with a microstructure on the surface, which actively disturbs the laminar flow structure at the boundary to inhibit the intensity of turbulent flow and thus reduce the resistance at the boundary, and is commonly used on the outer surface of an airplane, a high-speed train and a ship transportation tool. By reducing the resistance received by the transportation tool during movement, the efficiency of transportation is improved, and the energy loss is reduced.

[0003] During the use of the drag reduction film, the service life of the drag reduction film is affected by multiple factors such as fluid impact and ultraviolet radiation. In the high altitude during the flight of an airplane, the ocean during the navigation of a ship and some strong light areas, the intensity of ultraviolet radiation can reach two to three times that of normal urban outdoor ultraviolet radiation. Long-term exposure to such an environment with high ultraviolet radiation intensity causes the drag reduction film to rapidly age and fail, the surface microstructure of the drag reduction film is damaged, the surface energy of the drag reduction film is increased, and the drag reduction efficiency of the drag reduction film is affected. Therefore, improving the ultraviolet aging resistance of the drag reduction film is of great significance to improving the environmental adaptability and service life of the drag reduction film. SUMMARY

[0004] The application aims to provide a drag reduction film resistant to ultraviolet aging and a preparation process thereof, improve the ultraviolet aging resistance of the drag reduction film, enhance the environmental adaptability and service life of the drag reduction film, and solve the problems of insufficient ultraviolet aging resistance, insufficient environmental adaptability and short service life of the drag reduction film.

[0005] To solve the above technical problems, the application provides the following technical scheme. A preparation process of a drag reduction film resistant to ultraviolet aging, in particular to the following steps. Step 1: modifying polycaprolactone type TPU prepolymer by using silane coupling agent KH-560 and hindered amine light stabilizer HALs and extruding to obtain TPU particles of a base layer; Step 2: preparing disulfide bond modified acrylate adhesive by using disulfide amino acid modified aliphatic polyurethane acrylate; Step 3: blending and extruding silicone modified acrylate resin and functional additives to obtain silicone modified acrylate resin particles; Step 4: extruding the TPU particles of the base layer to form a TPU base film, coating the disulfide bond modified acrylate adhesive on the TPU base film after plasma cleaning and drying, forming an adhesive layer on the TPU base film, extruding and hot-rolling the silicone modified acrylate resin particles to form a silicone modified acrylate resin surface layer, laying the silicone modified acrylate resin surface layer on the adhesive layer, and performing lamination and composite, photo-thermal synergistic curing to obtain the drag reduction film resistant to ultraviolet aging.

[0006] As a limitation of the present application, the preparation method of the base layer TPU particles is: The polycaprolactone type TPU prepolymer, silane coupling agent KH-560 and hindered amine light stabilizer HALs are mixed and added to a twin-screw extruder, melt blended at 170-180℃, 200-250rpm for 3-5min, then polyethylene glycol monoacrylate is added, the speed is increased to 300-350rpm, and the blending is continued for 5-10min, then dibenzoyl peroxide is added at the end of the extruder and extruded, the extrusion temperature is 190-200℃, the screw speed is 200-250rpm, and the die temperature is 170-180℃, to obtain the base layer TPU particles.

[0007] As a limitation of the present application, the base layer TPU particles include, by mass fraction: 85-95 parts of polycaprolactone type TPU prepolymer, 1-2 parts of polyethylene glycol monoacrylate, 3-5 parts of silane coupling agent KH-560, 1.5-2.5 parts of hindered amine light stabilizer HALs, and 1-2 parts of dibenzoyl peroxide.

[0008] During the extrusion process, the silane coupling agent KH-560 hydrolyzes to form silicon hydroxyl groups (-Si(OH)3), which undergo condensation reactions with the hydroxyl groups (-OH) at the ends of the TPU prepolymer molecular chains to form covalent bonds (-Si-O-), and the silane coupling agent KH-560 is grafted onto the TPU prepolymer. Then, the epoxy groups (-CH(O)CH-) at the other end of the silane coupling agent undergo ring-opening reactions with the amine groups (-NH-) of the hindered amine light stabilizer HALs to form covalent bonds (-O-CH2-CH-NH-), and the HALs are also grafted onto the TPU prepolymer, improving the material's aging resistance. Finally, under the action of the crosslinking agent dibenzoyl peroxide, the TPU prepolymer polymerizes to form a three-dimensional crosslinked network, and the formation of the crosslinked structure improves the material's strength and heat resistance, enhances the stress transfer capability within the material, and reduces the expansion of microcracks during the aging process. In addition, polyethylene glycol monoacrylate is introduced during the process, and the acrylate groups (-COOCH=CH2) on the polyethylene glycol monoacrylate molecules can combine with the terminal hydroxyl groups (-OH) of the TPU or the epoxy groups (-CH(O)CH-) of the KH-560 through hydrogen bonding or covalent bonding, and the flexible polyethylene glycol segments improve the compatibility between the TPU base and the acrylate adhesive layer. The ether bonds (-O-) in the polyethylene glycol monoacrylate molecules can also form a hydrogen bond network with the polar groups (-COOH, -OH) in the adhesive layer, further improving the bonding strength between the TPU base and the adhesive layer, thereby improving the material's peel resistance.

[0009] As a limitation of the present application, the preparation method of the disulfide bond modified acrylate adhesive is: The aliphatic polyurethane acrylate is added into butyl acetate, dissolved at 50-60℃, 300-400rpm magnetic stirring for 20-30min, then the dithio carbamate is added, continue to stir for 5-10min, cool to 35-45℃, add silane coupling agent KH-560 and dibenzoyl peroxide, stir evenly, ultrasonic dispersion for 20-30min, to obtain disulfide bond modified acrylate adhesive.

[0010] As the limitation of the application, the disulfide bond modified acrylate adhesive includes: 60-70 parts of aliphatic polyurethane acrylate, 40-60 parts of butyl acetate, 2-4 parts of dithio carbamate, 1.5-2.5 parts of silane coupling agent KH-560, 1-2 parts of dibenzoyl peroxide, by mass fraction.

[0011] In the adhesive, the thio carbamate group (-NH-C(=S)-NH-) or sulfide bond (-S-) of the dithio carbamate and the carbon-carbon double bond (-C=C-) of the aliphatic polyurethane acrylate copolymerize to form a crosslinked network through a free radical addition reaction, the disulfide bond (-S-S-) of the dithio carbamate is embedded in the molecular chain of the aliphatic polyurethane acrylate, the disulfide bond has moderate bond energy and can reversibly break and recombine under light or heat conditions, absorb interface stress and repair microcracks, enhance the fatigue resistance and long-term service life of the material; the epoxy group (-CH(O)CH-) in the structure of the silane coupling agent KH-560 condenses with the terminal hydroxyl group (-OH) at the end of the molecular chain to form a covalent bond (-Si-O-), which is anchored in the adhesive and forms a covalent bond with the hydroxyl group (-OH) of the TPU base film through the silicon hydroxyl group (-Si(OH)3), thereby improving the interface bonding strength; the dibenzoyl peroxide initiates free radical polymerization to form a three-dimensional crosslinked network, thereby improving the tensile strength and heat resistance of the material.

[0012] As the limitation of the application, the preparation method of the organosilicon modified acrylic resin particles is: The organosilicon modified acrylic resin, hindered amine light stabilizer HALs and antioxidant 1010 are added into a twin-screw extruder, mixed at 140-150℃ for 5-10min, then the photoinitiator 1173 is added at the end of the extruder and extruded, the extrusion temperature is set to 160-170℃ and the die temperature is set to 150-160℃, to obtain organosilicon modified acrylic resin particles.

[0013] As the limitation of the application, the preparation method of the organosilicon modified acrylic resin is: Under the protection of nitrogen, butyl acrylate is added to solvent butyl acetate, dissolved at 60-70°C, 300-400 rpm magnetic stirring for 20-30 min, the speed is increased to 500-600 rpm, KH-570 modified butyl acrylate, pentaerythritol tetraacrylate and acrylic acid are added, continue to stir for 20-30 min, then add benzoyl peroxide, react at 80-90°C, 500-600 rpm for 3-5 h, after the reaction is completed, vacuum drying at 50-60°C, remove the solvent butyl acetate, to obtain silicone modified acrylic resin.

[0014] The silicone modified acrylic resin includes, by mass fraction: 50-70 parts of butyl acrylate, 30-50 parts of solvent butyl acetate, 25-35 parts of KH-570 modified butyl acrylate, 15-25 parts of pentaerythritol tetraacrylate, 10-20 parts of acrylic acid and 1-3 parts of benzoyl peroxide.

[0015] The preparation method of KH-570 modified butyl acrylate is: Silane coupling agent KH-570 and deionized water are added to solvent butyl acetate, stirred uniformly, adjust the pH to 5-6, hydrolyze at 60-70°C for 3-4 h, then under the protection of nitrogen, add butyl acrylate and benzoyl peroxide, react at 70-80°C for 4-5 h, after the reaction is completed, wash with acetone, dry at 50-60°C for 8-12 h, to obtain KH-570 modified butyl acrylate.

[0016] The mass ratio of butyl acrylate and silane coupling agent KH-570 is (48-52):1.

[0017] Butyl acrylate, KH-570 modified butyl acrylate, pentaerythritol acrylate and acrylic acid are copolymerized to form a modified acrylic resin containing siloxane segments; butyl acrylate structure contains long-chain alkyl, which provides flexible segments during polymerization, enhancing the flexibility of the resin; the siloxane segment in the structure of KH-570 modified butyl acrylate is combined with the main chain of the resin in the form of hydrogen bond or covalent bond, forming a siloxane-acrylate interpenetrating network, improving the strength, weather resistance and long-term stability of the resin; acrylic acid plays a role in adjusting the polarity during copolymerization, the polar carboxyl group (-COOH) of acrylic acid can form hydrogen bonds with polar groups in the substrate or adhesive layer, such as urethane bond (-NHCO-), enhancing the bonding strength between the resin and the substrate or adhesive layer; pentaerythritol acrylate as a crosslinking monomer, contains four acrylates in its structure, forms a multi-branch crosslinking structure under the action of initiator, reduces the molecular weight distribution of the resin, the molecular chain length is more uniform, the strength and processing performance of the resin are improved.

[0018] As the limitation of the application, the organic silicon modified acrylic resin particles include: 80-90 parts of organic silicon modified acrylic resin, 0.3-0.5 parts of hindered amine light stabilizer HALS, 0.1-0.3 parts of antioxidant 1010, and 1-3 parts of photoinitiator 1173 by mass fraction.

[0019] As the limitation of the application, when the TPU base film is formed by extrusion, the process parameters include: screw rotation speed: 250-300 rpm, extrusion temperature: 180-190 DEG C, and die temperature: 170-180 DEG C; when plasma cleaning, argon and oxygen are introduced, and the process parameters include: argon flow: 70-80 sccm, oxygen flow: 20-30 sccm, plasma power: 80-100 W, and cleaning time: 1-3 min; when forming the adhesive layer, the drying process parameters include: drying temperature: 60-70 DEG C, and drying time: 15-20 min; when extruding and hot rolling, the process parameters include: melting temperature: 170-180 DEG C, extrusion temperature: 160-170 DEG C, rolling temperature: 130-140 DEG C, and rolling pressure: 0.3-0.7 MPa; the thickness of the base film is 30-50 microns; the thickness of the adhesive layer is 20-30 microns; and the thickness of the organic silicon modified acrylic resin surface layer is 30-50 microns.

[0020] After the TPU base film is formed by extrusion and plasma cleaning, under the action of active particles in the plasma, the surface-attached residual additives and other pollutants in the extrusion process are stripped, the active particles react with the C-H bond on the surface of the TPU base film in the process, and polar groups (-OH, -COOH) are introduced, the surface polarity is increased, and the surface roughness is also increased, the combination strength between the base film and the adhesive layer is enhanced through the synergistic effect of the two; the organic silicon modified acrylic resin particles are formed under the action of hot rolling of the mold roller, and microstructures are formed on the surface, so that the aerodynamic performance is optimized, and the purpose of reducing frictional resistance is achieved.

[0021] A UV aging-resistant drag reduction film is prepared by the preparation method in any one of the above.

[0022] Compared with the prior art, the application has the following advantages: The present application introduces hindered amine light stabilizer HALS and silane coupling agent KH-560 into the base TPU resin, the silane coupling agent is connected with the hindered amine light stabilizer at one end, and is connected with the TPU molecular chain at the other end, which significantly enhances the strength, heat resistance and aging resistance of the material; a glue layer is formed on the base film, the disulfide bond of the bis-thio carbamate in the glue layer absorbs the interface stress and repairs the micro-cracks, enhances the fatigue resistance and long service life of the material, the silane coupling agent KH-560 is combined with the hydroxyl group of the TPU base film through the silicon hydroxyl group to form a covalent bond, and the interface bonding strength is improved; the surface layer is an acrylic resin formed by copolymerization, which contains flexible alkyl chains and siloxane segments, and the strength, weather resistance and long-term stability of the resin are improved; the surface layer forms a microstructure through hot rolling, optimizes the aerodynamic performance, and achieves the purpose of reducing friction resistance. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present application will be described below in a clear and complete manner. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. The terms used in the embodiments are used for describing specific specific embodiments, rather than limiting the protection scope of the present application. The amount used in the embodiments is a laboratory small test, which can be scaled up proportionally. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor are within the scope of protection of the present application.

[0024] Polycaprolactone type TPU prepolymer (Mn=2000), polyethylene glycol monoacrylate (Mw=2000, hydroxyl value: 50 mgKOH / g), aliphatic polyurethane acrylate (viscosity: 2000 mPa·s), thermoplastic polyurethane resin particles (Mn=20000, viscosity: 25000 mPa·s), acrylate adhesive (Mn=10000, viscosity: 8000 mPa·s), thermosetting acrylic resin (Mn=8000, viscosity: 3000 mPa·s).

[0025] The preparation method of the butyl acrylate modified by KH-570 is as follows: 2g of silane coupling agent KH-570 and 2g of deionized water are added to 100mL of solvent butyl acetate, stirred uniformly, the pH is adjusted to 6, hydrolyzed at 60℃ for 3h, then 100g of butyl acrylate and 1g of benzoyl peroxide are added under nitrogen protection, and reacted at 80℃ for 5h. After the reaction is completed, wash with acetone, dry at 50℃ for 12h, and obtain the butyl acrylate modified by KH-570.

[0026] Example 1: a preparation process of a UV aging resistant drag reduction film, specifically: Step 1: 95 g polycaprolactone type TPU prepolymer, 3 g silane coupling agent KH-560 and 1.5 g hindered amine light stabilizer HALs were mixed and added to a twin-screw extruder, melt blended at 180 °C and 200 rpm for 5 min, then 1 g polyethylene glycol monoacrylate was added, the speed was increased to 350 rpm, and the blending was continued for 10 min, then 1 g dibenzoyl peroxide was added at the end of the extruder, the extrusion temperature was 190 °C, the screw speed was 200 rpm, and the die temperature was 170 °C, to obtain TPU particles of the base layer; Step 2: 70 g aliphatic polyurethane acrylate was added to 60 g butyl acetate, dissolved at 55 °C and 400 rpm magnetic stirring for 30 min, then 2 g bis-thio carbamate was added, and stirring was continued for 10 min, the temperature was lowered to 40 °C, 1.5 g silane coupling agent KH-560 and 1 g dibenzoyl peroxide were added and stirred uniformly, and ultrasonic dispersion was performed for 20 min to obtain a disulfide bond modified acrylate adhesive; Step 3: 70 g butyl acrylate was added to 50 g solvent butyl acetate under nitrogen protection, dissolved at 60 °C and 300 rpm magnetic stirring for 30 min, the speed was increased to 500 rpm, 25 g KH-570 modified butyl acrylate, 15 g pentaerythritol tetraacrylate and 10 g acrylic acid were added, and stirring was continued for 30 min, then 1.5 g benzoyl peroxide was added, and the reaction was carried out at 80 °C and 500 rpm for 4 h, after the reaction was completed, the solvent butyl acetate was removed by vacuum drying at 60 °C to obtain a silicone modified acrylic resin; Step 4: 90 g silicone modified acrylic resin, 0.3 g hindered amine light stabilizer HALs and 0.1 g antioxidant 1010 were added to a twin-screw extruder, mixed at 150 °C for 10 min, then 1.5 g photoinitiator 1173 was added at the end of the extruder, the extrusion temperature was set to 170 °C, and the die temperature was set to 160 °C to obtain silicone modified acrylic resin particles; Step 5: The base layer TPU particles were added to the extruder to extrude into a film, the screw rotation speed was set to 300 rpm, the extrusion temperature was 190°C, and the die temperature was 180°C, to obtain a TPU base film with a thickness of 50 μm. The TPU base film was transferred to a plasma device and cleaned with argon and oxygen plasma, with an argon flow rate of 70 sccm, an oxygen flow rate of 30 sccm, a plasma power of 100 W, and a cleaning time of 3 min. After cleaning, a disulfide bond modified acrylate adhesive was coated on the surface, and after coating, it was dried at 65°C for 20 min to form an adhesive layer with a thickness of 20 μm. The silicone-modified acrylic resin particles were added to a twin-screw extruder and extruded and rolled, with a melting temperature of 170°C, an extrusion temperature of 160°C, a rolling temperature of 140°C, and a rolling pressure of 0.5 MPa, to form a 40 μm silicone-modified acrylic resin surface layer. The silicone-modified acrylic resin surface layer was laid on the adhesive layer and laminated at 110°C and 0.3 MPa, and then light-heat synergistically cured, with a 365 nm ultraviolet light source and an energy density of 800 mJ / cm 2 , a heat curing temperature of 120°C, and a curing time of 20 min, to obtain a UV aging resistant drag reduction film.

[0027] Example 2: A preparation process of a UV aging resistant drag reduction film, specifically: Step 1: 90 g of polycaprolactone TPU prepolymer, 3 g of silane coupling agent KH-560, and 1.5 g of hindered amine light stabilizer HALs were mixed and added to a twin-screw extruder, melted and blended at 180°C and 200 rpm for 5 min, then 1 g of polyethylene glycol monoacrylate was added, the rotation speed was increased to 350 rpm, and the blending was continued for 10 min. Then 1 g of dibenzoyl peroxide was added at the end of the extruder and extruded, with an extrusion temperature of 190°C, a screw rotation speed of 200 rpm, and a die temperature of 170°C, to obtain base layer TPU particles; Step 2: 65 g of aliphatic polyurethane acrylate was added to 55 g of butyl acetate and dissolved by magnetic stirring at 55°C and 400 rpm for 30 min. Then 2 g of bis-thio carbamate was added and stirred for another 10 min. The temperature was lowered to 40°C, 1.5 g of silane coupling agent KH-560 and 1 g of dibenzoyl peroxide were added and stirred uniformly, and ultrasonic dispersion was performed for 20 min to obtain a disulfide bond modified acrylate adhesive; Step 3: Under nitrogen protection, 60 g of butyl acrylate was added to 50 g of solvent butyl acetate, dissolved at 60°C, 300 rpm magnetic stirring for 30 min, the speed was increased to 500 rpm, 20 g of KH-570 modified butyl acrylate, 20 g of pentaerythritol tetraacrylate and 10 g of acrylic acid were added, and after stirring for 30 min, 1.5 g of benzoyl peroxide was added, and the reaction was carried out at 80°C, 500 rpm for 4 h. After the reaction was completed, 60°C vacuum drying was carried out to remove the solvent butyl acetate, and a silicone-modified acrylic resin was obtained; Step 4: 85 g of silicone-modified acrylic resin, 0.6 g of hindered amine light stabilizer HALs and 0.3 g of antioxidant 1010 were added to a twin-screw extruder, and after mixing at 150°C for 10 min, 1.5 g of photoinitiator 1173 was added at the end of the extruder. The extrusion temperature was set to 170°C, and the die temperature was set to 160°C to obtain silicone-modified acrylic resin particles; Step 5: The substrate layer TPU particles were extruded into a film in the extruder, the screw speed was set to 300 rpm, the extrusion temperature was set to 190°C, and the die temperature was set to 180°C to obtain a TPU substrate film with a thickness of 50 μm. The TPU substrate film was transferred to a plasma device and plasma cleaned by introducing argon and oxygen. The argon flow was set to 70 sccm, the oxygen flow was set to 30 sccm, the plasma power was set to 100 W, and the cleaning time was set to 3 min. After cleaning, a disulfide bond-modified acrylic adhesive was coated on the surface, and after coating, the adhesive layer was formed by drying at 65°C for 20 min, with a thickness of 20 μm. The silicone-modified acrylic resin particles were extruded and rolled in a twin-screw extruder, with a melting temperature of 170°C, an extrusion temperature of 160°C, a rolling temperature of 140°C, and a rolling pressure of 0.5 MPa. A 50 μm thick silicone-modified acrylic resin surface layer was formed, which was laid on the adhesive layer. After light-thermal synergistic curing at 110°C and 0.3 MPa, the light source was 365 nm ultraviolet light with an energy density of 800 mJ / cm 2 , the heat curing temperature was 120°C, and the curing time was 20 min. An ultraviolet aging resistant drag reduction film was obtained.

[0028] Example 3: A preparation process of an ultraviolet aging resistant drag reduction film, specifically: Step 1: 85 g polycaprolactone type TPU prepolymer, 3 g silane coupling agent KH-560 and 1.5 g hindered amine light stabilizer HALs were mixed and added to a twin-screw extruder, melt blended at 180°C and 200 rpm for 5 min, then 1 g polyethylene glycol monoacrylate was added, the speed was increased to 350 rpm, and the blending was continued for 10 min, then 1 g dibenzoyl peroxide was added at the end of the extruder, the extrusion temperature was 190°C, the screw speed was 200 rpm, and the die temperature was 170°C, to obtain TPU particles of the base layer; Step 2: 60 g aliphatic polyurethane acrylate was added to 50 g butyl acetate, dissolved at 55°C and 400 rpm magnetic stirring for 30 min, then 2 g bis-thio carbamate was added, and stirring was continued for 10 min, the temperature was lowered to 40°C, 1.5 g silane coupling agent KH-560 and 1 g dibenzoyl peroxide were added and stirred uniformly, and ultrasonic dispersion was performed for 20 min to obtain a disulfide bond modified acrylate adhesive; Step 3: Under nitrogen protection, 50 g butyl acrylate was added to 50 g solvent butyl acetate, dissolved at 60°C and 300 rpm magnetic stirring for 30 min, the speed was increased to 500 rpm, 25 g KH-570 modified butyl acrylate, 25 g pentaerythritol tetraacrylate and 20 g acrylic acid were added, and stirring was continued for 30 min, then 1.5 g benzoyl peroxide was added, and the reaction was carried out at 80°C and 500 rpm for 4 h, after the reaction was completed, 60°C vacuum drying was performed to remove the solvent butyl acetate, to obtain a silicone modified acrylic resin; Step 4: 80 g silicone modified acrylic resin, 0.6 g hindered amine light stabilizer HALs and 0.3 g antioxidant 1010 were added to a twin-screw extruder, mixed at 150°C for 10 min, then 1.5 g photoinitiator 1173 was added at the end of the extruder, the extrusion temperature was set to 170°C, and the die temperature was set to 160°C, to obtain silicone modified acrylic resin particles; Step 5: The base layer TPU particles are added to the extruder to extrude a film, the screw rotation speed is set to 300 rpm, the extrusion temperature is 190°C, and the die temperature is 180°C, to obtain a TPU base film with a thickness of 50 μm. The TPU base film is transferred to a plasma device and cleaned with argon and oxygen plasma, with an argon flow rate of 70 sccm, an oxygen flow rate of 30 sccm, a plasma power of 100 W, and a cleaning time of 3 min. After cleaning, a disulfide bond modified acrylate adhesive is coated on the surface, and after coating, it is dried at 65°C for 20 min to form an adhesive layer with a thickness of 30 μm. The silicone-modified acrylic resin particles are added to a twin-screw extruder and extruded and rolled, with a melting temperature of 170°C, an extrusion temperature of 160°C, a rolling temperature of 140°C, and a rolling pressure of 0.5 MPa, to form a 50 μm silicone-modified acrylic resin surface layer. The silicone-modified acrylic resin surface layer is laid on the adhesive layer, and after lamination and compounding at 110°C and 0.3 MPa, it is light-heat synergistically cured, with a light source of 365 nm ultraviolet light and an energy density of 800 mJ / cm 2 , a heat curing temperature of 120°C, and a curing time of 20 min, to obtain a UV aging resistant drag reduction film.

[0029] Based on Example 1, the following control experiments are performed, specifically Comparative Example 1, Comparative Example 2, and Comparative Example 3, as described below: Comparative Example 1: This comparative example relates to a preparation process of a UV aging resistant drag reduction film, which differs from Example 1 in that the base film is prepared using thermoplastic polyurethane particles, specifically: Step 1: 70 g of aliphatic polyurethane acrylate is added to 60 g of butyl acetate, and after dissolution at 55°C with magnetic stirring at 400 rpm for 30 min, 2 g of bis-thio carbamate is added and stirring is continued for 10 min. The temperature is lowered to 40°C, 1.5 g of silane coupling agent KH-560 and 1 g of dibenzoyl peroxide are added, and stirring is uniform, and ultrasonic dispersion is performed for 20 min to obtain a disulfide bond modified acrylate adhesive; Step 2: Under nitrogen protection, 70 g of butyl acrylate is added to 50 g of solvent butyl acetate, and after dissolution at 60°C with magnetic stirring at 300 rpm for 30 min, the rotation speed is increased to 500 pm, 25 g of KH-570 modified butyl acrylate, 15 g of pentaerythritol tetraacrylate, and 10 g of acrylic acid are added, and stirring is continued for 30 min. After adding 1.5 g of benzoyl peroxide, the reaction is carried out at 80°C and 500 rpm for 4 h. After the reaction is completed, the solvent butyl acetate is removed by vacuum drying at 60°C to obtain a silicone-modified acrylic resin. Step 3: 90 g of silicone-modified acrylic resin, 0.3 g of hindered amine light stabilizer HALs, and 0.1 g of antioxidant 1010 were added to a twin-screw extruder, and after mixing at 150°C for 10 min, 1.5 g of photoinitiator 1173 was added at the end of the extruder, and the extrusion temperature was set to 170°C, and the die temperature was set to 160°C, to obtain silicone-modified acrylic resin particles; Step 4: The thermoplastic polyurethane particles were extruded into a film in an extruder, and the screw speed was set to 300 rpm, the extrusion temperature was set to 190°C, and the die temperature was set to 180°C, to obtain a TPU base film with a thickness of 50 μm. The TPU base film was transferred to a plasma device and plasma cleaned with argon and oxygen, with an argon flow rate of 70 sccm, an oxygen flow rate of 30 sccm, a plasma power of 100 W, and a cleaning time of 3 min. After cleaning, a disulfide-modified acrylic adhesive was coated on the surface, and after coating, the adhesive layer was dried at 65°C for 20 min, forming an adhesive layer with a thickness of 20 μm. The silicone-modified acrylic resin particles were extruded and rolled in a twin-screw extruder, with a melting temperature of 170°C, an extrusion temperature of 160°C, a rolling temperature of 140°C, and a rolling pressure of 0.5 MPa, to form a 50 μm thick silicone-modified acrylic resin surface layer. The silicone-modified acrylic resin surface layer was laid on the adhesive layer, and after lamination at 110°C and 0.3 MPa, the light-thermal synergistic curing was performed, with a 365 nm ultraviolet light source and an energy density of 800 mJ / cm 2 , a thermal curing temperature of 120°C, and a curing time of 20 min, to obtain an ultraviolet aging-resistant drag reduction film.

[0030] Comparative Example 2: This comparative example relates to a preparation process of an ultraviolet aging-resistant drag reduction film, which differs from Example 1 in that an unmodified acrylic adhesive is used, specifically: Step 1: 95 g of polycaprolactone TPU prepolymer, 3 g of silane coupling agent KH-560, and 1.5 g of hindered amine light stabilizer HALs were mixed and added to a twin-screw extruder, and after melting and blending at 180°C and 200 rpm for 5 min, 1 g of polyethylene glycol monoacrylate was added, and the speed was increased to 350 rpm, and after continuing to blend for 10 min, 1 g of dibenzoyl peroxide was added at the end of the extruder and extruded, with an extrusion temperature of 190°C, a screw speed of 200 rpm, and a die temperature of 170°C, to obtain TPU base particles; Step 2: 70 g of butyl acrylate was added to 50 g of solvent butyl acetate under nitrogen protection, dissolved at 60°C with 300 rpm magnetic stirring for 30 min, the stirring speed was increased to 500 rpm, 25 g of KH-570 modified butyl acrylate, 15 g of pentaerythritol tetraacrylate and 10 g of acrylic acid were added, and after stirring for 30 min, 1.5 g of benzoyl peroxide was added, and the reaction was carried out at 80°C with 500 rpm for 4 h. After the reaction was completed, 60°C vacuum drying was performed to remove the solvent butyl acetate, and a silicone-modified acrylic resin was obtained; Step 3: 90 g of silicone-modified acrylic resin, 0.3 g of hindered amine light stabilizer HALs and 0.1 g of antioxidant 1010 were added to a twin-screw extruder, and after mixing at 150°C for 10 min, 1.5 g of photoinitiator 1173 was added at the end of the extruder. The extrusion temperature was set to 170°C, and the die temperature was set to 160°C to obtain silicone-modified acrylic resin particles; Step 5: The TPU base film was obtained by extruding the base layer TPU particles into a film with a screw speed of 300 rpm, an extrusion temperature of 190°C and a die temperature of 180°C, and the thickness was 50μm. The TPU base film was transferred to a plasma device and cleaned with argon and oxygen plasma. The argon flow was set to 70 sccm, the oxygen flow was set to 30 sccm, the plasma power was set to 100W, and the cleaning time was set to 3 min. After cleaning, an acrylate adhesive was coated on the surface, and after coating, the adhesive layer was formed by drying at 65°C for 20 min, and the thickness was 20μm. The silicone-modified acrylic resin particles were extruded and rolled in a twin-screw extruder, with a melting temperature of 170°C, an extrusion temperature of 160°C, a rolling temperature of 140°C, and a rolling pressure of 0.5MPa. The silicone-modified acrylic resin surface layer was formed with a thickness of 50μm. The silicone-modified acrylic resin surface layer was laid on the adhesive layer, and after lamination and compounding at 110°C and 0.3MPa, the light-thermal synergistic curing was performed with a UV light source of 365nm and an energy density of 800mJ / cm 2 , and the heat curing temperature was 120°C and the curing time was 20min. An ultraviolet aging resistant drag reduction film was obtained.

[0031] Comparative Example 3: This comparative example relates to a preparation process of an ultraviolet aging resistant drag reduction film, which is different from Example 1 in that the surface layer uses a thermosetting acrylic resin, specifically: Step 1: 95 g polycaprolactone type TPU prepolymer, 3 g silane coupling agent KH-560 and 1.5 g hindered amine light stabilizer HALs were mixed and added to a twin-screw extruder, melt blended at 180°C and 200 rpm for 5 min, then 1 g polyethylene glycol monoacrylate was added, the speed was increased to 350 rpm, and the blending was continued for 10 min, then 1 g dibenzoyl peroxide was added at the end of the extruder, the extrusion temperature was 190°C, the screw speed was 200 rpm, and the die temperature was 170°C, to obtain TPU granules for the base layer; Step 2: 70 g aliphatic polyurethane acrylate was added to 60 g butyl acetate, dissolved at 55°C and 400 rpm magnetic stirring for 30 min, then 2 g bis-thio carbamate was added, stirring for 10 min, cooling to 40°C, adding 1.5 g silane coupling agent KH-560 and 1 g dibenzoyl peroxide, stirring uniformly, and ultrasonic dispersion for 20 min to obtain disulfide bond modified acrylate adhesive; Step 3: The TPU granules for the base layer were added to the extruder to extrude a film, the screw speed was set to 300 rpm, the extrusion temperature was 190°C, and the die temperature was 180°C, to obtain a TPU base film with a thickness of 50 μm. The TPU base film was transferred to a plasma device and cleaned by plasma with argon and oxygen, the argon flow was set to 70 sccm, the oxygen flow was set to 30 sccm, the plasma power was set to 100 W, and the cleaning time was set to 3 min. After cleaning, the disulfide bond modified acrylate adhesive was coated on the surface, and after coating, it was dried at 65°C for 20 min to form an adhesive layer with a thickness of 20 μm. The thermosetting acrylic resin granules were laid flat on the adhesive layer and rolled at 130°C with a mold roller at a pressure of 0.5 MPa to form a 40 μm acrylic resin surface layer. After rolling, the light-thermal synergistic curing was performed with a 365 nm ultraviolet light source at an energy density of 800 mJ / cm 2 , and the thermal curing temperature was 120°C for 20 min to obtain an ultraviolet aging resistant drag reduction film.

[0032] Test experiment: The ultraviolet aging resistant drag reduction film test samples were prepared according to the respective examples and comparative examples, and were cut into dumbbell-shaped samples (total length 150 mm, sample width 25 mm, narrow parallel part length 33 mm, narrow parallel part width 6 mm, gauge length 25 mm). The tensile strength test, ultraviolet aging resistance test, wet heat aging resistance test and fatigue performance test were performed.

[0033] Tensile strength test: the tensile strength test of the drag reduction film refers to "Determination of tensile properties of plastics - Part 3: test conditions for films and sheets" (GB / T 1040.3-2006), the dumbbell-shaped sample is clamped and fixed at both ends by the upper and lower clamps of the tensile testing machine, the testing machine is started, and the sample is stretched at a tensile rate of 50 mm / min until the sample breaks, the maximum load and the elongation at break are recorded, and the tensile strength of the sample is calculated. Each kind of drag reduction film is tested 5 times, and the test results are averaged.

[0034] UV aging resistance test: the UV aging resistance test of the drag reduction film refers to "Methods of exposure to laboratory light sources - Part 3: fluorescent UV lamps" (GB / T 16422.3-2022), 5 samples of each drag reduction film are placed in a UV aging test chamber, the temperature in the aging chamber is 60℃, the irradiation light source is 365nm UV light, the irradiation intensity is 0.89W / m 2 , after aging for 500h, the tensile strength after aging is measured, the test results are averaged, and the tensile strength retention rate of the sample is calculated.

[0035] Moisture and heat aging resistance test: the moisture and heat aging resistance test of the drag reduction film refers to "Technical conditions for moisture and heat test chamber" (GB / T 10586-2006), 5 samples of each drag reduction film are placed in a moisture and heat test chamber, the temperature in the aging chamber is 85℃, the relative humidity is 85%RH, and the samples are taken out after aging for 500h. The tensile strength after aging is measured, the test results are averaged, and the tensile strength retention rate of the sample is calculated.

[0036] Fatigue performance test: the fatigue performance test uses a high-frequency fatigue testing machine, 10 samples of each drag reduction film are placed on the test table of the testing machine and fixed with clamps, the testing machine is started, and the tensile stress is loaded in a sinusoidal mode. The loading frequency is set to 10Hz, the cyclic stress ratio is 0.1, the cyclic maximum stress is set to 70% of the stress corresponding to the tensile strength of the sample, and the test is stopped after 10 6 cycles. The tensile strength retention rate of the sample is tested.

[0037]

[0038] Conclusion: from the test data, compared with the test results of the comparative examples, the tensile strength of the UV aging resistant drag reduction film provided by the examples is better than that of each comparative example. After UV aging, moisture and heat aging, or fatigue cycle, the tensile strength retention rate of the UV aging resistant drag reduction film prepared by the examples is still higher than that of each comparative example. The UV aging resistant drag reduction film prepared by the examples has good tensile strength, UV aging resistance, moisture and heat aging resistance, and long service life, and can solve the problems of poor UV aging resistance, weak environmental use, and insufficient long-term service life of the drag reduction film.

[0039] It will be apparent to those skilled in the art that the application is not limited to the details of the above-exemplified embodiments and that the present application can be implemented in other particular forms without departing from the spirit or essential characteristics of the present application. The embodiments should therefore be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the above description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims

1. A process for the preparation of a UV-aging resistant drag-reducing film, characterized in that: Specifically: Step 1: modify polycaprolactone TPU prepolymer with silane coupling agent KH-560 and hindered amine light stabilizer HALs and extrude to obtain TPU granules for base layer; Step 2: use bis-thio-carbamate modified aliphatic polyurethane acrylate to prepare disulfide bond modified acrylate adhesive; Step 3: blend and extrude silicone modified acrylic resin and functional additives to obtain silicone modified acrylic resin granules; Step 4: extrude TPU granules for base layer to form TPU base film, coat disulfide bond modified acrylate adhesive after plasma cleaning and dry, form adhesive layer on TPU base film, extrude and hot roll silicone modified acrylic resin surface layer to form silicone modified acrylic resin surface layer, lay silicone modified acrylic resin surface layer on adhesive layer, laminate, and light-heat synergistic curing to obtain UV aging resistant drag reduction film.

2. The process for the preparation of a UV-aging resistant drag-reducing film according to claim 1, characterized in that: The preparation method of the TPU granules for base layer is as follows: Mix polycaprolactone TPU prepolymer, silane coupling agent KH-560 and hindered amine light stabilizer HALs, add to a twin-screw extruder, melt blend at 170-180℃ and 200-250rpm for 3-5min, then add polyethylene glycol monoacrylate, increase the speed to 300-350rpm, continue to blend for 5-10min, then add dibenzoyl peroxide at the end of the extruder and extrude, the extrusion temperature is 190-200℃, the screw speed is 200-250rpm, and the die temperature is 170-180℃ to obtain TPU granules for base layer.

3. The process for the preparation of a UV-aging resistant drag-reducing film according to claim 2, characterized in that: The TPU granules for base layer include, by mass fraction: 85-95 parts of polycaprolactone TPU prepolymer, 1-2 parts of polyethylene glycol monoacrylate, 3-5 parts of silane coupling agent KH-560, 1.5-2.5 parts of hindered amine light stabilizer HALs, and 1-2 parts of dibenzoyl peroxide.

4. The process for preparing a UV-aging resistant drag-reducing film according to claim 1, characterized in that: The preparation method of the disulfide bond modified acrylate adhesive is as follows: Add aliphatic polyurethane acrylate to butyl acetate, dissolve under magnetic stirring at 50-60℃ and 300-400rpm for 20-30min, then add bis-thio-carbamate, continue to stir for 5-10min, cool to 35-45℃, add silane coupling agent KH-560 and dibenzoyl peroxide, stir evenly, and ultrasonic dispersion for 20-30min to obtain disulfide bond modified acrylate adhesive.

5. The process for the preparation of a UV-aging resistant drag-reducing film according to claim 4, characterized in that: The disulfide bond modified acrylate adhesive includes, by mass fraction: 60-70 parts of aliphatic polyurethane acrylate, 40-60 parts of butyl acetate, 2-4 parts of bis-thio-carbamate, 1.5-2.5 parts of silane coupling agent KH-560, and 1-2 parts of dibenzoyl peroxide.

6. The process for the preparation of a UV-aging resistant drag-reducing film according to claim 1, characterized in that: The preparation method of the silicone modified acrylic resin granules is as follows: The silicone-modified acrylic resin, the hindered amine light stabilizer HALs and the antioxidant 1010 are added into a double-screw extruder, and after mixing at 140-150℃ for 5-10 min, the photoinitiator 1173 is added at the end of the extruder and extruded, with the extrusion temperature set at 160-170℃ and the die temperature set at 150-160℃, to obtain silicone-modified acrylic resin particles.

7. The process for the preparation of a UV-aging resistant drag-reducing film according to claim 6, characterized in that: The silicone-modified acrylic resin is prepared by the following method: Under nitrogen protection, the butyl acrylate is added into the solvent butyl acetate, dissolved at 60-70℃ under magnetic stirring at 300-400 rpm for 20-30 min, the stirring speed is increased to 500-600 rpm, the butyl acrylate is modified by KH-570, pentaerythritol tetraacrylate and acrylic acid are added, and after continuous stirring for 20-30 min, the benzoyl peroxide is added, and the reaction is carried out at 80-90℃ under stirring at 500-600 rpm for 3-5 h, and after the reaction is completed, the solvent butyl acetate is removed by vacuum drying at 50-60℃, to obtain the silicone-modified acrylic resin.

8. The process for the preparation of a UV-aging resistant drag-reducing film according to claim 6, characterized in that: The silicone-modified acrylic resin particles include, by mass fraction: 80-90 parts of silicone-modified acrylic resin, 0.3-0.5 parts of hindered amine light stabilizer HALs, 0.1-0.3 parts of antioxidant 1010, and 1-3 parts of photoinitiator 1173.

9. The process for the preparation of a UV ageing resistant drag reducing film according to claim 1, characterized in that: When the TPU base film is extruded, the process parameters include: screw speed: 250-300 rpm, extrusion temperature: 180-190℃, and die temperature: 170-180℃. When the plasma cleaning is carried out, argon and oxygen are introduced, and the process parameters include: argon flow rate: 70-80 sccm, oxygen flow rate: 20-30 sccm, plasma power: 80-100 W, and cleaning time: 1-3 min; when the adhesive layer is formed, the drying process parameters include: drying temperature: 60-70℃, and drying time: 15-20 min; when the extrusion and hot rolling are carried out, the process parameters include: melting temperature: 170-180℃, extrusion temperature: 160-170℃, rolling temperature: 130-140℃, and rolling pressure: 0.3-0.7 MPa; the base film thickness is 30-50 μm; the adhesive layer thickness is 20-30 μm; and the silicone-modified acrylic resin surface layer thickness is 30-50 μm. The silicone-modified acrylic resin is prepared by the method of any one of claims 1-9.

10. A UV-aging resistant drag-reducing film characterized in that: ​

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