A hydrophobic and antifouling automobile paint protective film and preparation method thereof

Abstract

The invention discloses a hydrophobic antifouling automobile paint surface protective film and a preparation method thereof, and relates to the technical field of polymer materials. When preparing the hydrophobic antifouling automobile paint surface protective film, the present invention reacts diethyl phosphite with 1,3-propylene glycol to obtain a dihydroxy phosphate monomer; polymerizes 1-chloromethyl-2,4-diisocyanobenzene with a dihydroxy phosphate monomer and 2,2-3,3-4,4-5,5-octafluoro-1,6-hexanediol to obtain polyurethane; reacts polyurethane with methacrylate-2,2,6,6-tetramethyl-4-piperidyl ester to obtain pre-modified polyurethane; reacts pre-modified polyurethane with dopamine to obtain modified polyurethane; reacts nano-kaolin with 3-mercaptopropyltriethoxysilane and butane-3-boric acid in sequence to obtain modified nano-kaolin; and melt-blended the modified polyurethane with the modified nano-kaolin and then calendered to obtain the hydrophobic antifouling automobile paint surface protective film. The hydrophobic and antifouling automobile paint surface protective film prepared by the invention has excellent flame retardant, anti-aging, antifouling and self-repairing properties.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, in particular to a hydrophobic and anti-fouling automobile paint surface protective film and a preparation method thereof. Background Art

[0002] The number of cars in use is increasing. During use, the paint layer on the surface of the car will be damaged due to natural or human factors. In order to better protect the appearance of the vehicle, car paint protection film products have come into being. The raw materials used in traditional car paint protection films are polymer materials. Under long-term rain erosion and sun exposure, they will age, affecting the appearance of the car and reducing the protection ability of the car paint surface. Therefore, it is necessary to develop a car paint protection film with anti-fouling and anti-aging properties. Summary of the invention

[0003] The object of the present invention is to provide a hydrophobic and antifouling automobile paint protective film and a preparation method thereof, so as to solve the problems existing in the prior art.

[0004] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0005] A hydrophobic and antifouling automobile paint protective film is prepared by reacting polyurethane with methacrylate-2,2,6,6-tetramethyl-4-piperidyl ester to obtain pre-modified polyurethane; reacting the pre-modified polyurethane with dopamine to obtain modified polyurethane; and melt-blending the modified polyurethane with modified nano-kaolin and then calendering to form the film.

[0006] As an optimization, the polyurethane is prepared by polymerizing 1-chloromethyl-2,4-diisocyanobenzene with a dihydroxy phosphate monomer and 2,2-3,3-4,4-5,5-octafluoro-1,6-hexanediol.

[0007] As an optimization, the bishydroxy phosphate monomer is prepared by reacting diethyl phosphite with 1,3-propylene glycol.

[0008] As an optimization, the modified nano-kaolin is prepared by reacting nano-kaolin with 3-mercaptopropyltriethoxysilane and butane-3-boric acid in sequence.

[0009] A method for preparing a hydrophobic and antifouling automobile paint protective film comprises the following preparation steps:

[0010] (1) adding diethyl phosphite and 1,3-propylene glycol in a molar ratio of 1:2 to toluene with a mass of 20 to 30 times that of diethyl phosphite, adding potassium hydroxide with a mass of 0.2 to 0.3 times that of diethyl phosphite, stirring at 80 to 90° C. and 300 to 500 r / min for 2 to 3 hours, adding deionized water with an equal volume of toluene, mixing evenly, extracting the organic phase, and drying at 5 to 7 Pa and 40 to 50° C. for 6 to 7 hours to obtain a bishydroxy phosphate monomer;

[0011] (2) 1-chloromethyl-2,4-diisocyanobenzene, dihydroxy phosphate monomer, and 2,2-3,3-4,4-5,5-octafluoro-1,6-hexanediol are added in a molar ratio of 1:(0.3-0.4):(0.3-0.4) to N,N-dimethylformamide (20-24 times the mass of 1-chloromethyl-2,4-diisocyanobenzene), and the mixture is stirred at 70-80° C. and 300-500 r / min under a nitrogen atmosphere to react. 2,2-3,3-4,4-5,5-octafluoro-1,6-hexanediol (0.06-0.08 times the molar amount of 1-chloromethyl-2,4-diisocyanobenzene) is added to the reaction system every half an hour, and the content of isocyanate groups is monitored. The remaining isocyanate groups are quenched with anhydrous ethanol, cooled to room temperature, and heated at 5-7 Pa, 50-60 ℃ and dried for 6 to 7 hours to obtain polyurethane; polyurethane, methacrylate-2,2,6,6-tetramethyl-4-piperidyl ester, azobisisobutyronitrile and toluene are mixed evenly in a mass ratio of 1:(0.2-0.3):(0.03-0.05):(20-24), stirred at 60-70℃, 300-500r / min for reaction for 2-3 hours, and dried at 5-7Pa, 50-60℃ for 6-7 hours to obtain pre-modified polyurethane; pre-modified polyurethane, dopamine, triethylamine and toluene are mixed evenly in a mass ratio of 1:(0.4-0.6):(0.06-0.08):(20-30), stirred at 50-60℃, 300-500r / min for reaction for 2-3 hours, and dried at 5-7Pa, 50-60℃ for 6-7 hours to obtain modified polyurethane;

[0012] (3) Mix nano-kaolin and anhydrous ethanol in a mass ratio of 1:(50-60), add silane hydrolyzate in an amount of 8-10 times the mass of nano-kaolin, stir and react at 70-80°C, 300-500r / min for 1-2h, filter, wash with anhydrous ethanol and deionized water 3-5 times each, dry at 70-80°C for 5-7h, and obtain pre-modified nano-kaolin; mix pre-modified nano-kaolin, butane-3-diboric acid, azobisisobutyronitrile, N,N-dimethylformamide in a mass ratio of 1:(2-3):(0.03-0.05):(20-24), stir and react at 50-60°C, 300-500r / min for 4-6h, filter, wash with anhydrous ethanol and deionized water 3-5 times each, dry at 5-7Pa, 50-60°C for 5-7h, and obtain modified nano-kaolin;

[0013] (4) The modified polyurethane and modified nano-kaolin were mixed uniformly in a mass ratio of 1:(0.03-0.05), placed in a hot melt machine, stirred at 180-190°C and 300-500 r / min for 10-20 min, and then sent to a calender for calendering. The mixture was allowed to stand for 5-6 h to obtain a hydrophobic and anti-fouling automotive paint protective film.

[0014] As an optimization, the reaction process of the dihydroxy phosphate monomer in step (1) is:

[0015]

[0016] As an optimization, the method for monitoring the content of isocyanate groups in step (2) is to detect the isocyanate group content of the reaction system by dibutyl amine-hydrochloric acid titration method, and stop adding 2,2-3,3-4,4-5,5-octafluoro-1,6-hexanediol when the content of unreacted isocyanate groups is less than 4-6% of the initial number of isocyanate groups.

[0017] As an optimization, the silane hydrolyzate in step (3) is prepared by uniformly mixing 3-mercaptopropyltriethoxysilane and anhydrous ethanol in a mass ratio of 1:(20-30), adjusting the pH to 4-6 with a 1 mol / L oxalic acid aqueous solution, and stirring at 10-30° C. and 200-300 r / min for 1-2 h.

[0018] As an optimization, the process parameters of the calendering molding in step (4) are: setting the calender temperature to 150-160° C., the calendering speed to 50-60 m / min, and the pressure to 24-30 MPa.

[0019] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0020] When preparing the hydrophobic and antifouling automobile paint surface protective film, the present invention comprises the following steps: reacting diethyl phosphite with 1,3-propylene glycol to obtain a dihydroxy phosphate monomer; polymerizing 1-chloromethyl-2,4-diisocyanobenzene with the dihydroxy phosphate monomer and 2,2-3,3-4,4-5,5-octafluoro-1,6-hexanediol to obtain polyurethane; reacting polyurethane with methacrylate-2,2,6,6-tetramethyl-4-piperidyl ester to obtain pre-modified polyurethane; reacting the pre-modified polyurethane with dopamine to obtain modified polyurethane; reacting nano-kaolin with 3-mercaptopropyltriethoxysilane to obtain pre-modified nano-kaolin; reacting the pre-modified nano-kaolin with butane-3-boric acid to obtain modified nano-kaolin; and melt-blending the modified polyurethane with the modified nano-kaolin and then calendering to obtain the hydrophobic and antifouling automobile paint surface protective film.

[0021] Firstly, diethyl phosphite is reacted with 1,3-propylene glycol to obtain a bishydroxy phosphate monomer; the bishydroxy phosphate monomer can participate in the polymerization reaction of polyurethane, introduce phosphorus element and phosphorus-hydrogen bond into polyurethane, and the introduction of phosphorus element can give the hydrophobic antifouling automobile paint protective film excellent flame retardant properties; 1-chloromethyl-2,4-diisocyanobenzene is polymerized with bishydroxy phosphate monomer and 2,2-3,3-4,4-5,5-octafluoro-1,6-hexanediol to obtain polyurethane, and chlorine atoms and a large number of fluorine atoms are introduced into the polyurethane molecular chain; fluorine atoms have low reactivity and hydrophobicity, and can give the hydrophobic antifouling automobile paint protective film excellent antifouling properties; polyurethane is reacted with methacrylate-2,2, The pre-modified polyurethane is prepared by reacting 6,6-tetramethyl-4-piperidinyl ester, and the phosphorus-hydrogen bond on the polyurethane molecular chain reacts with the double bond on methacrylate-2,2,6,6-tetramethyl-4-piperidinyl ester to undergo a phosphorus-hydrogen addition reaction, and a hindered amine structure is introduced on the side chain of the pre-modified polyurethane molecule. The hindered amine structure can capture and remove active free radicals in the polymer material, decompose hydroperoxides, and prevent the further progress of the photo-oxidative aging reaction, thereby giving the hydrophobic and anti-fouling automobile paint protective film excellent anti-aging properties; the pre-modified polyurethane is reacted with dopamine to prepare a modified polyurethane, and the chlorine atoms on the side chain of the pre-modified polyurethane molecule react with the amino group on the dopamine to introduce an ortho-diphenol group on the side chain of the modified polyurethane molecule.

[0022] Secondly, the nano-kaolin is reacted with 3-mercaptopropyltriethoxysilane to obtain pre-modified nano-kaolin; the pre-modified nano-kaolin is reacted with butane-3-boric acid to obtain modified nano-kaolin, the mercapto groups on the surface of the pre-modified nano-kaolin react with the carbon-carbon double bonds on butane-3-boric acid to introduce boric acid groups on the modified nano-kaolin, the boric acid groups on the modified nano-kaolin can react with the o-diphenol groups on the side chains of the modified polyurethane molecules to undergo esterification to form reversible boric acid ester bonds, forming a cross-linked network, and giving the hydrophobic and anti-fouling automobile paint protective film excellent self-healing properties; nano-kaolin is a two-dimensional inorganic nanomaterial that can form a physical barrier in the hydrophobic and anti-fouling automobile paint protective film, causing a tortuous effect in the diffusion process of the penetrating molecules, extending the diffusion path, and improving the barrier properties of the hydrophobic and anti-fouling automobile paint protective film, isolating the penetration of oxygen and water vapor, protecting the automobile paint surface, and giving the hydrophobic and anti-fouling automobile paint protective film excellent anti-fouling properties. DETAILED DESCRIPTION

[0023] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0024] Example 1

[0025] A method for preparing a hydrophobic and antifouling automobile paint protective film, the method for preparing the hydrophobic and antifouling automobile paint protective film comprising the following preparation steps:

[0026] (1) adding diethyl phosphite and 1,3-propylene glycol in a molar ratio of 1:2 to toluene with a mass 20 times that of diethyl phosphite, adding potassium hydroxide with a mass 0.2 times that of diethyl phosphite, stirring at 80° C. and 300 r / min for 3 h, adding deionized water with an equal volume of toluene, mixing evenly, extracting the organic phase, and drying at 5 Pa and 40° C. for 7 h to obtain a bishydroxy phosphate monomer;

[0027] (2) 1-chloromethyl-2,4-diisocyanobenzene, dihydroxy phosphate monomer, and 2,2-3,3-4,4-5,5-octafluoro-1,6-hexanediol were added in a molar ratio of 1:0.3:0.3 to N,N-dimethylformamide (20 times the mass of 1-chloromethyl-2,4-diisocyanobenzene), and the mixture was stirred at 70° C. and 300 r / min under a nitrogen atmosphere to react. 2,2-3,3-4,4-5,5-octafluoro-1,6-hexanediol (0.06 times the molar amount of 1-chloromethyl-2,4-diisocyanobenzene) was added to the reaction system every half an hour, and the isocyanate group content of the reaction system was detected by dibutylamine-hydrochloric acid titration method. When the unreacted isocyanate group content was less than 4% of the initial isocyanate group number, the addition of 2 was stopped. ,2-3,3-4,4-5,5-octafluoro-1,6-hexanediol, quench the remaining isocyanate groups with anhydrous ethanol, cool to room temperature, dry at 5Pa, 50℃ for 7h to obtain polyurethane; mix polyurethane, methacrylate-2,2,6,6-tetramethyl-4-piperidyl ester, azobisisobutyronitrile, and toluene in a mass ratio of 1:0.2:0.03:20, stir and react at 60℃, 300r / min for 3h, and dry at 5Pa, 50℃ for 7h to obtain pre-modified polyurethane; mix pre-modified polyurethane, dopamine, triethylamine, and toluene in a mass ratio of 1:0.4:0.06:20, stir and react at 50℃, 300r / min for 3h, and dry at 5Pa, 50℃ for 7h to obtain modified polyurethane;

[0028] (3) 3-Mercaptopropyltriethoxysilane and anhydrous ethanol were mixed at a mass ratio of 1:20, the pH was adjusted to 4 with a 1 mol / L oxalic acid aqueous solution, and the mixture was stirred at 10°C and 200 r / min for 2 h to obtain a silane hydrolyzate; nano-kaolin and anhydrous ethanol were mixed at a mass ratio of 1:50, silane hydrolyzate with a mass of 8 times that of the nano-kaolin was added, the mixture was stirred at 70°C and 300 r / min for 2 h, filtered, and filtered with anhydrous ethanol. The pre-modified nano-kaolin was prepared by washing with anhydrous ethanol and deionized water for 3 times, drying at 70°C for 5 hours, and then mixing the pre-modified nano-kaolin, butane-3-boric acid, azobisisobutyronitrile, and N,N-dimethylformamide in a mass ratio of 1:2:0.03:20, stirring at 50°C and 300 r / min for 6 hours, filtering, washing with anhydrous ethanol and deionized water for 3 times, and then drying at 5Pa and 50°C for 7 hours to obtain modified nano-kaolin.

[0029] (4) The modified polyurethane and modified nano-kaolin were mixed evenly in a mass ratio of 1:0.03, placed in a hot melt machine, stirred at 180°C and 300 r / min for 20 min, and then sent to a calender for calendering. The calender temperature was set to 150°C, the calendering speed was set to 50 m / min, the pressure was set to 24 MPa, and the mixture was allowed to stand for 6 h to obtain a hydrophobic and anti-fouling automotive paint protective film.

[0030] Example 2

[0031] A method for preparing a hydrophobic and antifouling automobile paint protective film, the method for preparing the hydrophobic and antifouling automobile paint protective film comprising the following preparation steps:

[0032] (1) adding diethyl phosphite and 1,3-propylene glycol in a molar ratio of 1:2 to toluene with a mass 25 times that of diethyl phosphite, adding potassium hydroxide with a mass 0.25 times that of diethyl phosphite, stirring at 85°C and 400 r / min for 2.5 hours, adding deionized water with an equal volume of toluene, mixing evenly, extracting the organic phase, and drying at 6Pa and 45°C for 6.5 hours to obtain a bishydroxy phosphate monomer;

[0033] (2) 1-chloromethyl-2,4-diisocyanobenzene, dihydroxy phosphate monomer, and 2,2-3,3-4,4-5,5-octafluoro-1,6-hexanediol were added in a molar ratio of 1:0.35:0.35 to N,N-dimethylformamide (22 times the mass of 1-chloromethyl-2,4-diisocyanobenzene), and the mixture was stirred at 75° C. and 400 r / min under a nitrogen atmosphere to react. 2,2-3,3-4,4-5,5-octafluoro-1,6-hexanediol (0.07 times the molar amount of 1-chloromethyl-2,4-diisocyanobenzene) was added to the reaction system every half an hour, and the isocyanate group content of the reaction system was detected by a dibutylamine-hydrochloric acid titration method. When the unreacted isocyanate group content was less than 5% of the initial isocyanate group number, the addition of 2,2-3,3-4,4-5,5-octafluoro-1,6-hexanediol was stopped. ,3-4,4-5,5-octafluoro-1,6-hexanediol, quench the remaining isocyanate groups with anhydrous ethanol, cool to room temperature, dry at 6Pa, 55℃ for 6.5h to obtain polyurethane; mix polyurethane, methacrylate-2,2,6,6-tetramethyl-4-piperidyl ester, azobisisobutyronitrile, and toluene in a mass ratio of 1:0.25:0.04:22, stir and react at 65℃, 400r / min for 2.5h, and dry at 6Pa, 55℃ for 6.5h to obtain pre-modified polyurethane; mix pre-modified polyurethane, dopamine, triethylamine, and toluene in a mass ratio of 1:0.5:0.07:25, stir and react at 55℃, 400r / min for 2.5h, and dry at 6Pa, 55℃ for 6.5h to obtain modified polyurethane;

[0034] (3) 3-Mercaptopropyltriethoxysilane and anhydrous ethanol were mixed at a mass ratio of 1:25, the pH was adjusted to 5 with a 1 mol / L oxalic acid aqueous solution, and the mixture was stirred at 20°C and 250 r / min for 1.5 h to obtain a silane hydrolyzate; nano-kaolin and anhydrous ethanol were mixed at a mass ratio of 1:55, 9 times the mass of the nano-kaolin was added with the silane hydrolyzate, the mixture was stirred at 75°C and 400 r / min for 1.5 h, filtered, and filtered with anhydrous ethanol. The pre-modified nano-kaolin was prepared by washing with ethanol and deionized water for 4 times, drying at 75°C for 6 hours, and then mixing the pre-modified nano-kaolin, butane-3-boric acid, azobisisobutyronitrile, and N,N-dimethylformamide in a mass ratio of 1:2.5:0.04:22, stirring at 55°C and 400 r / min for 5 hours, filtering, washing with anhydrous ethanol and deionized water for 4 times, and then drying at 6Pa and 55°C for 6 hours to obtain modified nano-kaolin.

[0035] (4) The modified polyurethane and modified nano-kaolin were mixed evenly in a mass ratio of 1:0.04, placed in a hot melt machine, stirred at 185°C and 400 r / min for 15 min, and then sent to a calender for calendering. The calender temperature was set to 155°C, the calendering speed was set to 55 m / min, the pressure was set to 27 MPa, and the mixture was allowed to stand for 5.5 h to obtain a hydrophobic and anti-fouling automotive paint protective film.

[0036] Example 3

[0037] A method for preparing a hydrophobic and antifouling automobile paint protective film, the method for preparing the hydrophobic and antifouling automobile paint protective film comprising the following preparation steps:

[0038] (1) adding diethyl phosphite and 1,3-propylene glycol in a molar ratio of 1:2 to toluene with a mass of 30 times that of diethyl phosphite, adding potassium hydroxide with a mass of 0.3 times that of diethyl phosphite, stirring at 90° C. and 500 r / min for 2 h, adding deionized water with an equal volume of toluene, mixing evenly, extracting the organic phase, and drying at 7 Pa and 50° C. for 6 h to obtain a bishydroxy phosphate monomer;

[0039] (2) 1-chloromethyl-2,4-diisocyanobenzene, dihydroxy phosphate monomer, and 2,2-3,3-4,4-5,5-octafluoro-1,6-hexanediol were added in a molar ratio of 1:0.4:0.4 to N,N-dimethylformamide (24 times the mass of 1-chloromethyl-2,4-diisocyanobenzene), and the mixture was stirred at 80° C. and 500 r / min under a nitrogen atmosphere to react. 2,2-3,3-4,4-5,5-octafluoro-1,6-hexanediol (0.08 times the molar amount of 1-chloromethyl-2,4-diisocyanobenzene) was added to the reaction system every half an hour, and the isocyanate group content of the reaction system was detected by a dibutylamine-hydrochloric acid titration method. When the unreacted isocyanate group content was less than 6% of the initial isocyanate group number, the addition of 2 was stopped. ,2-3,3-4,4-5,5-octafluoro-1,6-hexanediol, quench the remaining isocyanate groups with anhydrous ethanol, cool to room temperature, dry at 7Pa, 60℃ for 6h to obtain polyurethane; mix polyurethane, methacrylate-2,2,6,6-tetramethyl-4-piperidyl ester, azobisisobutyronitrile, and toluene in a mass ratio of 1:0.3:0.05:24, stir and react at 70℃, 500r / min for 2h, and dry at 7Pa, 60℃ for 6h to obtain pre-modified polyurethane; mix pre-modified polyurethane, dopamine, triethylamine, and toluene in a mass ratio of 1:0.6:0.08:30, stir and react at 60℃, 500r / min for 2h, and dry at 7Pa, 60℃ for 6h to obtain modified polyurethane;

[0040] (3) 3-Mercaptopropyltriethoxysilane and anhydrous ethanol were mixed at a mass ratio of 1:30, the pH was adjusted to 6 with a 1 mol / L oxalic acid aqueous solution, and the mixture was stirred at 30°C and 300 r / min for 1 h to obtain a silane hydrolyzate; nano-kaolin and anhydrous ethanol were mixed at a mass ratio of 1:60, 10 times the mass of nano-kaolin was added to the silane hydrolyzate, the mixture was stirred at 80°C and 500 r / min for 1 h, filtered, and filtered. The pre-modified nano-kaolin was prepared by washing with ethanol and deionized water for 5 times, drying at 80°C for 5 hours, and mixing the pre-modified nano-kaolin, butane-3-diboric acid, azobisisobutyronitrile, and N,N-dimethylformamide in a mass ratio of 1:3:0.05:24, stirring at 60°C and 500 r / min for 4 hours, filtering, washing with anhydrous ethanol and deionized water for 5 times, and drying at 7Pa and 60°C for 5 hours to obtain modified nano-kaolin.

[0041] (4) The modified polyurethane and modified nano-kaolin were mixed evenly in a mass ratio of 1:0.05, placed in a hot melt machine, stirred at 190°C and 500 r / min for 10 min, and then sent to a calender for calendering. The calender temperature was set to 160°C, the calendering speed was set to 60 m / min, the pressure was set to 30 MPa, and the mixture was allowed to stand for 5 h to obtain a hydrophobic and anti-fouling automotive paint protective film.

[0042] Comparative Example 1

[0043] The preparation method of the hydrophobic antifouling automobile paint protective film of Comparative Example 1 is different from that of Example 2 in that step (1) is not performed, and step (2) is modified as follows: 1-chloromethyl-2,4-diisocyanobenzene, 1,6-hexanediol, and 2,2-3,3-4,4-5,5-octafluoro-1,6-hexanediol are added in a molar ratio of 1:0.35:0.35 to N,N-dimethylformamide with a mass of 22 times that of 1-chloromethyl-2,4-diisocyanobenzene, and the mixture is stirred at 75°C and 400r / min under a nitrogen atmosphere to react, and 2,2-3,3-4,4-5,5-octafluoro-1,6-hexanediol with a molar mass of 0.07 times that of 1-chloromethyl-2,4-diisocyanobenzene is added to the reaction system every half an hour, and the isocyanate group content of the reaction system is detected by dibutylamine-hydrochloric acid titration method. When the unreacted isocyanate group content is less than 0.05, the reaction mixture is stirred at 400r / min under a nitrogen atmosphere to react, and the reaction mixture is stirred at 75°C and 400r / min to react, and the reaction mixture is stirred at 400r / min under a nitrogen atmosphere to react, and the reaction mixture is stirred at 400r / min under a nitrogen atmosphere to react, and the reaction mixture is stirred at 400r / min under a molar mass of 0.05 times that of 1-chloromethyl-2,4-diisocyanobenzene. Stop adding 2,2-3,3-4,4-5,5-octafluoro-1,6-hexanediol when the number of initial isocyanate groups is 5%, quench the remaining isocyanate groups with anhydrous ethanol, cool to room temperature, and dry at 6Pa, 55°C for 6.5 hours to obtain polyurethane; mix polyurethane, methacrylate-2,2,6,6-tetramethyl-4-piperidyl ester, azobisisobutyronitrile, and toluene in a mass ratio of 1:0.25:0.04:22, stir and react at 65°C, 400r / min for 2.5 hours, and dry at 6Pa, 55°C for 6.5 hours to obtain pre-modified polyurethane; mix pre-modified polyurethane, dopamine, triethylamine, and toluene in a mass ratio of 1:0.5:0.07:25, stir and react at 55°C, 400r / min for 2.5 hours, and dry at 6Pa, 55°C for 6.5 hours to obtain modified polyurethane. The remaining steps are the same as in Example 2.

[0044] Comparative Example 2

[0045] The preparation method of the hydrophobic and antifouling automobile paint protective film of Comparative Example 2 is different from that of Example 2 only in step (2). Step (2) is modified as follows: 1-chloromethyl-2,4-diisocyanobenzene, dihydroxy phosphate monomer, and 1,6-hexanediol are added in a molar ratio of 1:0.35:0.35 to N,N-dimethylformamide (22 times the mass of 1-chloromethyl-2,4-diisocyanobenzene), and the mixture is stirred at 75°C and 400r / min under a nitrogen atmosphere to react. 1,6-hexanediol (0.07 times the molar amount of 1-chloromethyl-2,4-diisocyanobenzene) is added to the reaction system every half an hour, and the isocyanate group content of the reaction system is detected by dibutylamine-hydrochloric acid titration. When the unreacted isocyanate group content is less than the initial isocyanate group content, the reaction mixture is stirred at 400r / min under a nitrogen atmosphere. When the amount of 1,6-hexanediol is 5%, the addition of 1,6-hexanediol is stopped, the remaining isocyanate groups are quenched with anhydrous ethanol, the mixture is cooled to room temperature, and dried at 6Pa, 55°C for 6.5 hours to obtain polyurethane; polyurethane, methacrylate-2,2,6,6-tetramethyl-4-piperidyl ester, azobisisobutyronitrile, and toluene are mixed uniformly in a mass ratio of 1:0.25:0.04:22, stirred at 65°C, 400r / min for 2.5 hours, and dried at 6Pa, 55°C for 6.5 hours to obtain pre-modified polyurethane; pre-modified polyurethane, dopamine, triethylamine, and toluene are mixed uniformly in a mass ratio of 1:0.5:0.07:25, stirred at 55°C, 400r / min for 2.5 hours, and dried at 6Pa, 55°C for 6.5 hours to obtain modified polyurethane. The remaining steps are the same as those in Example 2.

[0046] Comparative Example 3

[0047] The preparation method of the hydrophobic and antifouling automotive paint protective film of Comparative Example 3 is different from that of Example 2 only in step (2). Step (2) is modified as follows: 1-chloromethyl-2,4-diisocyanobenzene, dihydroxy phosphate monomer, and 2,2-3,3-4,4-5,5-octafluoro-1,6-hexanediol are added in a molar ratio of 1:0.35:0.35 to N,N-dimethylformamide (22 times the mass of 1-chloromethyl-2,4-diisocyanobenzene), and the mixture is stirred at 75° C. and 400 r / min under a nitrogen atmosphere to react, and 2,2-3,3-4,4-5,5-octafluoro-1,6-hexanediol (0.07 times the molar mass of 1-chloromethyl-2,4-diisocyanobenzene) is added to the reaction system every half an hour. 5,5-octafluoro-1,6-hexanediol, and the isocyanate group content of the reaction system is detected by dibutylamine-hydrochloric acid titration method. When the unreacted isocyanate group content is less than 5% of the initial isocyanate group number, stop adding 2,2-3,3-4,4-5,5-octafluoro-1,6-hexanediol, quench the remaining isocyanate groups with anhydrous ethanol, cool to room temperature, dry at 6Pa, 55°C for 6.5h, and obtain polyurethane; polyurethane, dopamine, triethylamine, and toluene are mixed uniformly in a mass ratio of 1:0.5:0.07:25, stirred at 55°C, 400r / min for 2.5h, and dried at 6Pa, 55°C for 6.5h to obtain modified polyurethane. The remaining steps are the same as in Example 2.

[0048] Comparative Example 4

[0049] The preparation method of the hydrophobic antifouling automobile paint protective film of Comparative Example 4 is different from that of Example 2 only in step (2). Step (2) is modified as follows: 1-chloromethyl-2,4-diisocyanobenzene, dihydroxy phosphate monomer, and 2,2-3,3-4,4-5,5-octafluoro-1,6-hexanediol are added in a molar ratio of 1:0.35:0.35 to N,N-dimethylformamide (22 times the mass of 1-chloromethyl-2,4-diisocyanobenzene), and the mixture is stirred at 75° C. and 400 r / min under a nitrogen atmosphere to react, and 2,2-3,3-4,4-5,5-octafluoro-1,6-hexanediol (0.07 times the molar amount of 1-chloromethyl-2,4-diisocyanobenzene) is added to the reaction system every half an hour. Alcohol, and the isocyanate group content of the reaction system is detected by dibutylamine-hydrochloric acid titration method. When the unreacted isocyanate group content is less than 5% of the initial isocyanate group number, stop adding 2,2-3,3-4,4-5,5-octafluoro-1,6-hexanediol, quench the remaining isocyanate groups with anhydrous ethanol, cool to room temperature, and dry at 6Pa, 55°C for 6.5h to obtain polyurethane; polyurethane, methacrylate-2,2,6,6-tetramethyl-4-piperidyl ester, azobisisobutyronitrile, and toluene are mixed uniformly in a mass ratio of 1:0.25:0.04:22, stirred at 65°C, 400r / min for 2.5h, and dried at 6Pa, 55°C for 6.5h to obtain modified polyurethane. The remaining steps are the same as in Example 2.

[0050] Comparative Example 5

[0051] The preparation method of the hydrophobic antifouling automobile paint protective film of Comparative Example 5 is different from that of Example 2 in that step (3) is not performed, and step (4) is modified as follows: the modified polyurethane is placed in a hot melt machine, stirred at 185° C. and 400 r / min for 15 min, and then sent to a calender for calendering, the calender temperature is set to 155° C., the calendering speed is 55 m / min, the pressure is 27 MPa, and the calender is allowed to stand for 5.5 h to obtain a hydrophobic antifouling automobile paint protective film. The remaining steps are the same as those of Example 2.

[0052] Comparative Example 6

[0053] The preparation method of the hydrophobic antifouling automobile paint protective film of Comparative Example 6 is different from that of Example 2 in that step (3) is not performed, and step (4) is modified as follows: the modified polyurethane and nano-kaolin are mixed uniformly at a mass ratio of 1:0.04, placed in a hot melt machine, stirred at 185° C. and 400 r / min for 15 min, and then sent to a calender for calendering, the calender temperature is set to 155° C., the calendering speed is 55 m / min, the pressure is 27 MPa, and the calender is left to stand for 5.5 h to obtain a hydrophobic antifouling automobile paint protective film. The remaining steps are the same as those of Example 2.

[0054] Test Example 1

[0055] Flame retardant performance test

[0056] Test method: The examples and comparative examples were prepared into standard specimens according to GB / T2406.2, and the limiting oxygen index of the standard specimens was tested. The results are shown in Table 1.

[0057] Table 1

[0058]

[0059]

[0060] From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 6 in Table 1, it can be found that the hydrophobic and antifouling automobile paint protection film prepared by the present invention has good flame retardant properties.

[0061] By comparison, the limiting oxygen index of Examples 1 to 3 is greater than that of Comparative Example 1, indicating that diethyl phosphite is reacted with 1,3-propylene glycol to prepare a bishydroxy phosphate monomer; the bishydroxy phosphate monomer can participate in the polymerization reaction of polyurethane, introduce phosphorus elements and phosphorus-hydrogen bonds into the polyurethane, and the introduction of phosphorus elements can give the hydrophobic and anti-fouling automotive paint protective film excellent flame retardant properties.

[0062] Test Example 2

[0063] Anti-aging performance test

[0064] Test method: The tensile strength of the embodiment and the comparative example was tested on an electronic universal testing machine according to GB / T1040.3, and then the unstretched original sample was irradiated with a xenon arc lamp for 72 hours. The tensile strength of the embodiment and the comparative example after ultraviolet aging treatment was tested on an electronic universal testing machine according to GB / T1040.3, and the change rate of the tensile strength of the embodiment and the comparative example before and after ultraviolet aging treatment was calculated, tensile strength change rate = (tensile strength after ultraviolet aging treatment / original tensile strength of sample) × 100%. The results are shown in Table 2

[0065] Table 2

[0066]

[0067]

[0068] From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 6 in Table 2, it can be found that the hydrophobic and antifouling automobile paint protection film prepared by the present invention has good anti-aging performance.

[0069] By comparison, the change rate of tensile strength of Examples 1 to 3 is less than that of Comparative Example 3, indicating that the pre-modified polyurethane is prepared by reacting polyurethane with 2,2,6,6-tetramethyl-4-piperidinyl methacrylate, and the phosphorus-hydrogen bonds on the polyurethane molecular chain react with the double bonds on 2,2,6,6-tetramethyl-4-piperidinyl methacrylate to undergo a phosphorus-hydrogen addition reaction, and a hindered amine structure is introduced into the side chain of the pre-modified polyurethane molecule. The hindered amine structure can capture and remove active free radicals in the polymer material, decompose hydroperoxides, and prevent further photo-oxidative aging reactions, thereby giving the hydrophobic and anti-fouling automotive paint protective film excellent anti-aging properties.

[0070] Test Example 3

[0071] Antifouling performance test

[0072] Test method: The water drop contact angles of the embodiments and comparative examples were tested using the sessile drop method on an OCA20 contact angle meter, with the water drop volume being 5 μL. The results are shown in Table 3.

[0073] Table 3

[0074] Contact Angle Contact Angle Example 1 112.6° Comparative Example 1 113.7 Example 2 114.3° Comparative Example 2 87.2 Example 3 113.9° Comparative Example 3 113.5° Comparative Example 4 112.1° Comparative Example 5 99.2° Comparative Example 6 98.3°

[0075] From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 6 in Table 3, it can be found that the hydrophobic and antifouling automobile paint protection film prepared by the present invention has good antifouling performance.

[0076] By comparison, the contact angles of Examples 1 to 3 are greater than the contact angle of Comparative Example 2, indicating that polyurethane is prepared by polymerizing 1-chloromethyl-2,4-diisocyanobenzene with dihydroxy phosphate monomer and 2,2-3,3-4,4-5,5-octafluoro-1,6-hexanediol, and a large number of fluorine atoms are introduced into the polyurethane molecular chain; fluorine atoms have low reactivity and hydrophobicity, and can give the hydrophobic and anti-fouling automobile paint protective film excellent anti-fouling properties.

[0077] By comparison, the contact angles of Examples 1 to 3 are greater than those of Comparative Examples 5 to 6, indicating that the hydrophobic and antifouling automobile paint protective film is prepared by melt-blending the modified polyurethane and the modified nano-kaolin and then calendering. Nano-kaolin is a two-dimensional inorganic nanomaterial that can form a physical barrier in the hydrophobic and antifouling automobile paint protective film, causing a tortuous effect in the diffusion process of the penetrating molecules, extending the diffusion path, and improving the barrier properties of the hydrophobic and antifouling automobile paint protective film. It isolates the penetration of oxygen and water vapor, protects the automobile paint surface, and gives the hydrophobic and antifouling automobile paint protective film excellent antifouling properties.

[0078] Test Example 4

[0079] Self-healing performance test

[0080] Test method: According to GB / T1040.1, the embodiment and the comparative example are prepared into standard specimens, and their original tensile strength is tested by a tensile machine. Then, a 2mm deep and 10mm long crack is cut from the middle of the unstretched original specimen, and the specimen is placed in a mold, and kept at a humidity of 70% and a temperature of 40°C for 24 hours to obtain the repaired specimen. The tensile strength is tested by a tensile machine. The self-repair rate of the embodiment and the comparative example before and after repair is calculated, and the self-repair rate = (tensile strength of the specimen after repair / original tensile strength of the specimen) × 100%. The results are shown in Table 4.

[0081] Table 4

[0082]

[0083]

[0084] From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 6 in Table 4, it can be found that the hydrophobic and antifouling automobile paint protection film prepared by the present invention has good self-repairing performance.

[0085] By comparison, the self-repairing rates of Examples 1 to 3 are greater than those of Comparative Examples 4 to 6, indicating that the pre-modified polyurethane is reacted with dopamine to obtain the modified polyurethane, the chlorine atoms on the side chains of the pre-modified polyurethane molecules react with the amino groups on the dopamine, and the o-diphenol groups are introduced into the side chains of the modified polyurethane molecules; the nano-kaolin is reacted with 3-mercaptopropyltriethoxysilane to obtain the pre-modified nano-kaolin; the pre-modified nano-kaolin is reacted with butane-3-boric acid to obtain the modified nano-kaolin, the thiol groups on the surface of the pre-modified nano-kaolin react with the carbon-carbon double bonds on the butane-3-boric acid to introduce boric acid groups into the modified nano-kaolin, the boric acid groups on the modified nano-kaolin can undergo an esterification reaction with the o-diphenol groups on the side chains of the modified polyurethane molecules to form reversible borate ester bonds, thereby forming a cross-linked network, thereby imparting excellent self-repairing properties to the hydrophobic and anti-fouling automotive paint protective film.

[0086] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations within the meaning and scope of the equivalent elements of the claims be included in the invention. Any marking in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A hydrophobic and antifouling automobile paint protective film, characterized in that: The hydrophobic and antifouling automobile paint protection film is prepared by reacting polyurethane with methacrylate-2,2,6,6-tetramethyl-4-piperidyl ester to obtain pre-modified polyurethane; reacting the pre-modified polyurethane with dopamine to obtain modified polyurethane; and melt-blending the modified polyurethane with modified nano-kaolin and then calendering to obtain the polyurethane; the polyurethane is prepared by polymerizing 1-chloromethyl-2,4-diisocyanobenzene with a bishydroxy phosphate monomer and 2,2-3,3-4,4-5,5-octafluoro-1,6-hexanediol; the bishydroxy phosphate monomer is prepared by reacting diethyl phosphite with 1,3-propylene glycol; and the modified nano-kaolin is prepared by reacting nano-kaolin with 3-mercaptopropyltriethoxysilane and but-3-eneboric acid in sequence; The reaction process of the dihydroxy phosphate monomer is: 。 2. A method for preparing a hydrophobic and antifouling automobile paint protective film, characterized in that: The method comprises the following preparation steps: (1) Add diethyl phosphite and 1,3-propylene glycol in a molar ratio of 1:2 to toluene with a mass of 20 to 30 times that of diethyl phosphite, add potassium hydroxide with a mass of 0.2 to 0.3 times that of diethyl phosphite, stir at 80 to 90°C and 300 to 500 r / min for 2 to 3 hours, add deionized water with an equal volume of toluene, mix well, extract the organic phase, and dry at 5 to 7 Pa and 40 to 50°C for 6 to 7 hours to obtain a dihydroxy phosphate monomer; (2) 1-chloromethyl-2,4-diisocyanobenzene, dihydroxy phosphate monomer, and 2,2-3,3-4,4-5,5-octafluoro-1,6-hexanediol were added in a molar ratio of 1:(0.3~0.4):(0.3~0.4) to N,N-dimethylformamide (20~24 times the mass of 1-chloromethyl-2,4-diisocyanobenzene), and the mixture was stirred at 70~80°C and 300~500r / min under a nitrogen atmosphere. Every half an hour, 0.06~0.08 times the molar amount of 1-chloromethyl-2,4-diisocyanobenzene and 2,2-3,3-4,4-5,5-octafluoro-1,6-hexanediol were added to the reaction system. Fluoro-1,6-hexanediol, and monitor the content of isocyanate groups, quench the remaining isocyanate groups with anhydrous ethanol, cool to room temperature, and dry at 5-7Pa, 50-60℃ for 6-7h to obtain polyurethane; polyurethane, methacrylate-2,2,6,6-tetramethyl-4-piperidyl ester, azobisisobutyronitrile, and toluene are mixed uniformly in a mass ratio of 1:(0.2-0.3):(0.03-0.05):(20-24), stirred at 60-70℃, 300-500r / min for reaction for 2-3h, and dried at 5-7Pa, 50-60℃ for 6-7h to obtain pre-modified polyurethane; Pre-modified polyurethane, dopamine, triethylamine and toluene are uniformly mixed in a mass ratio of 1:(0.4-0.6):(0.06-0.08):(20-30), stirred at 50-60°C and 300-500 r / min for 2-3 hours, and dried at 5-7 Pa and 50-60°C for 6-7 hours to obtain modified polyurethane; (3) Mix nano-kaolin and anhydrous ethanol in a mass ratio of 1:(50-60), add silane hydrolyzate in an amount of 8-10 times the mass of nano-kaolin, stir and react at 70-80°C, 300-500 r / min for 1-2 hours, filter, wash with anhydrous ethanol and deionized water 3-5 times each, and dry at 70-80°C for 5-7 hours to obtain pre-modified nano-kaolin; mix pre-modified nano-kaolin, but-3-eneboric acid, azobisisobutyronitrile, N,N-dimethylformamide in a mass ratio of 1:(2-3):(0.03-0.05):(20-24), stir and react at 50-60°C, 300-500 r / min for 4-6 hours, filter, wash with anhydrous ethanol and deionized water 3-5 times each, and dry at 5-7 Pa, 50-60°C for 5-7 hours to obtain modified nano-kaolin; (4) The modified polyurethane and modified nano-kaolin were mixed evenly in a mass ratio of 1:(0.03-0.05), placed in a hot melt machine, stirred at 180-190°C and 300-500 r / min for 10-20 min, and then sent to a calender for calendering. The mixture was allowed to stand for 5-6 h to obtain a hydrophobic and anti-fouling automotive paint protective film.

3. The method for preparing a hydrophobic and antifouling automobile paint protective film according to claim 2, characterized in that: The reaction process of the dihydroxy phosphate monomer in step (1) is as follows: 。 4. The method for preparing a hydrophobic and antifouling automobile paint protective film according to claim 2, characterized in that: The method for monitoring the content of isocyanate groups in step (2) is to detect the isocyanate group content of the reaction system by di-n-butylamine-hydrochloric acid titration method, and stop adding 2,2-3,3-4,4-5,5-octafluoro-1,6-hexanediol when the content of unreacted isocyanate groups is less than 4-6% of the initial number of isocyanate groups.

5. The method for preparing a hydrophobic and antifouling automobile paint protective film according to claim 2, characterized in that: The silane hydrolyzate in step (3) is prepared by uniformly mixing 3-mercaptopropyltriethoxysilane and anhydrous ethanol in a mass ratio of 1:(20-30), adjusting the pH to 4-6 with a 1 mol / L oxalic acid aqueous solution, and stirring at 10-30° C. and 200-300 r / min for 1-2 h.

6. The method for preparing a hydrophobic and antifouling automobile paint protective film according to claim 2, characterized in that: The process parameters of the calendering molding in step (4) are: setting the calender temperature to 150-160° C., the calendering speed to 50-60 m / min, and the pressure to 24-30 MPa.

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