Anti-permeation automobile paint surface protective film and preparation method thereof

Abstract

The invention discloses an anti-permeation automobile paint surface protective film and a preparation method thereof, and relates to the technical field of paint surface protective films. The anti-permeation automobile paint surface protective film comprises a transparent base film, and a first coating and a second coating which are sequentially arranged on the surface of the transparent base film, the first coating is formed by epoxy resin modified polyurethane coating, and the second coating is formed by graphene modified polyurethane coating. The preparation method of the anti-permeation paint surface protection film comprises the following steps: coating an epoxy resin modified polyurethane coating on one surface of a transparent substrate film, carrying out primary heating curing, and annealing to form a first coating; the surface is further coated with a graphene modified polyurethane coating, secondary heating curing, ultraviolet irradiation and drying are carried out, and a second coating is formed; the anti-permeation automobile paint surface protection film is obtained. The automobile paint surface protective film prepared by the invention has excellent wear resistance, tensile strength and permeability resistance while ensuring the light transmittance, thereby having an excellent protective effect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of paint protection film, in particular to an anti-permeation automobile paint protection film and a preparation method thereof. BACKGROUND

[0002] With the increasing number of automobiles, automobile paint protection film is widely used as a product that can effectively protect the paint from damage from the outside world; polyurethane is often used as the basic component of the protection film, although it has certain protection and self-repairing performance, but the wear resistance is general, which leads to easy generation of large scratches and difficult self-repairing, and poor anti-permeation performance. In the prior art, although some nano materials are added to modify the protection film to increase the mechanical properties, the addition of some nano materials greatly reduces the light transmittance of the protection film, making the original paint pattern dark or even discolored, which cannot meet the existing demand.

[0003] In view of the above, it is of great significance to prepare an anti-permeation automobile paint protection film. SUMMARY

[0004] The present application aims to provide an anti-permeation automobile paint protection film and a preparation method thereof to solve the problems in the background art.

[0005] In order to solve the above technical problems, the present application provides the following technical scheme: An anti-permeation automobile paint protection film, comprising a transparent base film, and a first coating layer and a second coating layer arranged on the surface of the transparent base film in sequence; the first coating layer is formed by epoxy resin modified polyurethane coating, and the second coating layer is formed by graphene modified polyurethane coating. The epoxy resin modified polyurethane coating comprises the following raw materials in parts by weight: 40-50 parts of polyisocyanate, 70-80 parts of polyester polyol, 150 parts of solvent, 4-8 parts of 1,4-butanediol, 1-2 parts of triethylene glycol, 0.05-0.1 parts of dibutyltin dilaurate, 10-15 parts of branched epoxy resin, and 5-7 parts of multifunctional polyether amine.

[0006] More preferably, the preparation of the epoxy resin modified polyurethane coating comprises the following process: under a nitrogen atmosphere, polyisocyanate is added to the polyester polyol and mixed uniformly, stirred at 60-70 DEG C for 1-2 h; the solvent, 1,4-butanediol, triethylene glycol, dibutyltin dilaurate are added in sequence, stirred at 75-85 DEG C for 1-1.5 h, branched epoxy resin is added, and stirring is continued for 1-2 h, multifunctional polyether amine is added at 50-55 DEG C, and mixed uniformly to obtain the epoxy resin modified polyurethane coating.

[0007] Preferably, the branched epoxy resin is prepared by mixing ethylene glycol diglycidyl ether and tetrabutylammonium bromide uniformly, stirring at 125-130℃ for 10-15min under nitrogen atmosphere, adding neopentyl glycol diglycidyl ether, mixing trimethylolpropane and pentaerythritol allyl ether uniformly, preheating to 100℃, then gradually adding to the reaction system dropwise, controlling the dropwise adding time to be 2h, continuing to stir at 155-165℃ for 6-8h to obtain the branched epoxy resin.

[0008] Preferably, the branched epoxy resin comprises the following raw materials by mass fraction: 15-17 parts of ethylene glycol diglycidyl ether, 1.5-1.7 parts of tetrabutylammonium bromide, 2-2.2 parts of neopentyl glycol diglycidyl ether, 4.6-4.8 parts of trimethylolpropane, 1.2-1.4 parts of pentaerythritol allyl ether.

[0009] Preferably, the graphene modified polyurethane coating comprises the following raw materials by mass fraction: 30-40 parts of polyester polyol, 30-50 parts of polyether polyol, 40-50 parts of polyisocyanate, 200 parts of solvent, 10-12 parts of 1,4-butanediol, 1-2 parts of butenediol, 0.05-0.1 parts of dibutyltin dilaurate, 2-3 parts of modified graphene oxide, 0.5-1 parts of leveling agent, 0.01-0.03 parts of azobisisobutyronitrile.

[0010] Preferably, the graphene modified polyurethane coating is prepared by mixing polyester polyol and polyether polyol uniformly under nitrogen atmosphere, adding polyisocyanate, stirring at 60-70℃ for 1-2h; sequentially adding solvent, 1,4-butanediol, butenediol, dibutyltin dilaurate, stirring at 75-85℃ for 1-1.5h, adding modified graphene oxide, continuing to stir for 1-2h, adding leveling agent and azobisisobutyronitrile, stirring uniformly to obtain the graphene modified polyurethane coating.

[0011] Preferably, the modified graphene oxide is prepared by adding graphene oxide into N,N-dimethylformamide and ultrasonic dispersion, adding hyperbranched polyester, hydroxypropyl methacrylate, tetrabutylammonium bromide, heating and refluxing at 120-130℃ for 20-24h, filtering, washing, drying to obtain the modified graphene oxide. The modified graphene oxide comprises the following raw materials by mass fraction: 0.4-0.6 parts of graphene oxide, 50-60 parts of N,N-dimethylformamide, 10-12 parts of hyperbranched polyester, 2-3 parts of hydroxypropyl methacrylate, 0.02-0.03 parts of tetrabutylammonium bromide.

[0012] Preferably, the molecular weight of the hyperbranched polyester is 1500-2000.

[0013] More preferably, the preparation method of the anti-permeation automobile paint protective film comprises the following steps: Coating epoxy resin modified polyurethane paint on one side of the transparent base film, once heat curing, annealing, forming a first coating; further coating graphene modified polyurethane paint on the side, twice heat curing, ultraviolet light, drying, forming a second coating; obtaining the anti-permeation automobile paint protective film.

[0014] More preferably, in the process of heat curing, the temperature is 100-120 DEG C, the time is 4-6 min, in the process of annealing, the temperature is 65-75 DEG C, the time is 1-1.5 h, in the process of twice heat curing, the temperature is 110-130 DEG C, the time is 2-5 min, in the process of ultraviolet light, the power is 600-800 W, the time is 5-10 min, repeating three times, the interval is 4-5 min each time; The thickness of the first coating is 100-150 microns; the thickness of the second coating is 15-30 microns.

[0015] Compared with the prior art, the application has the beneficial effects: the first anti-permeation coating with high strength and high toughness is prepared by branched epoxy resin modified polyurethane paint, and the second wear-resistant anti-permeation coating is prepared by graphene modified polyurethane paint, forming a protective layer structure with lower rigidity on the top and higher rigidity on the bottom, which improves the anti-permeation and protection effect of the car paint protective film without significantly reducing the light transmittance.

[0016] The branched epoxy resin is prepared by using trimethylolpropane and pentaerythritol allyl ether as branched monomers and ethylene glycol diglycidyl ether and neopentyl glycol diglycidyl ether as linear monomers; the branched epoxy resin modified polyurethane paint is prepared to increase the crosslinking density, and the prepared branched epoxy resin has smaller viscosity, which is beneficial to dispersion in the polyurethane paint, thereby increasing the strength and anti-leakage performance of the protective film.

[0017] The graphene is modified by hyperbranched polyester and hydroxypropyl methacrylate; on the one hand, the dispersibility of graphene in the polyurethane paint is improved, and the wear resistance and anti-permeability of the protective film are improved; on the other hand, the multi-oxygen groups of the hyperbranched polyester can be inserted between the stacked layers of graphene to obtain exfoliated single-layer graphene sheets, which reduces the influence on the light transmittance and increases the transparency. However, the molecular weight of the hyperbranched polyester should not be too large, otherwise it is easy to cause aggregation, the intercalation modification of graphene is weakened, the film layer uniformity is reduced, and the wear resistance and light transmittance are reduced.

[0018] The present application is subjected to multiple interval ultraviolet treatment after heating and curing, which helps to protect the uniform crosslinking of double bonds in the film, further improves the anti-permeability performance, at the same time, the graphene oxide is also reduced to graphene, increases the combination tightness with the matrix, thereby improves the protection performance while reducing the influence on the light transmittance. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0020] It should be noted that the following parts are by mass fraction, and there is no special restriction on the purchase manufacturers of all raw materials involved in the present application, which exemplarily include: ethylene glycol diglycidyl ether, CAS number: 2224-15-9; neopentyl glycol diglycidyl ether, CAS number: 17557-23-2; trimethylolpropane, CAS number: 77-99-6; pentaerythritol allyl ether, CAS number: 91648-24-7; 1,4-butanediol, CAS number: 110-63-4; triethylene glycol, CAS number: 112-27-6; graphene oxide, particle size: 50-100 nm; hyperbranched polyester, model: Boltorn H30, provided by Shanghai Xibao Biotechnology Co., Ltd.; hydroxypropyl methacrylate, CAS number: 27813-02-1; butenediol, CAS number: 497-06-3; in the following examples, the above-mentioned and other raw materials used but not mentioned are commercially available.

[0021] In each embodiment and comparative example, the polyisocyanate is isophorone diisocyanate; the polyester polyol is Dynacoll 7150; the polyether polyol is PTMEG-1000; the solvent is a mixed solvent of toluene and N,N-dimethylformamide in a volume ratio of 1:1; the transparent base film is a PET film; and the leveling agent is BYK-333.

[0022] Example 1: A preparation method of an anti-permeation automobile paint surface protection film, comprising the following steps: Step one: preparation of branched epoxy resin; 16 parts of ethylene glycol diglycidyl ether and 1.6 parts of tetrabutylammonium bromide are uniformly mixed, stirred at 125℃ under nitrogen atmosphere for 15min, 2.1 parts of neopentyl glycol diglycidyl ether is added, and 4.7 parts of trimethylolpropane and 1.3 parts of pentaerythritol allyl ether are uniformly mixed and preheated to 100℃, then gradually added to the reaction system, the dropping time is controlled to be 2h, and the stirring is continued at 160℃ for 6h to obtain the branched epoxy resin; Step two: Preparation of epoxy resin modified polyurethane coating: 45 parts of polyisocyanate was added into 75 parts of polyester polyol and mixed uniformly under nitrogen atmosphere, stirred at 65℃ for 1.5h; 150 parts of solvent, 6 parts of 1,4-butanediol, 1.5 parts of triethylene glycol, 0.05 parts of dibutyltin dilaurate were added in turn, stirred at 80℃ for 1h, 12 parts of branched epoxy resin was added, and stirred for 1.5h, 6 parts of multifunctional polyether amine was added at 55℃, mixed uniformly, to obtain epoxy resin modified polyurethane coating; Step three: Preparation of modified graphene oxide: 0.5 parts of graphene oxide was added into 55 parts of N,N-dimethylformamide and ultrasonically dispersed uniformly, 11 parts of hyperbranched polyester, 2.5 parts of hydroxypropyl methacrylate, 0.02 parts of tetrabutylammonium bromide were added, heated to reflux and stirred at 125℃ for 24h, filtered, washed and dried to obtain modified graphene oxide; Step four: Preparation of graphene modified polyurethane coating: 35 parts of polyester polyol and 40 parts of polyether polyol were mixed uniformly under nitrogen atmosphere, 45 parts of polyisocyanate was added, stirred at 65℃ for 1.5h; 200 parts of solvent, 11 parts of 1,4-butanediol, 1.5 parts of butenediol, 0.05 parts of dibutyltin dilaurate were added in turn, stirred at 80℃ for 1h, 2.5 parts of modified graphene oxide was added, and stirred for 1.5h, 0.5 parts of leveling agent and 0.01 parts of azobisisobutyronitrile were added, stirred uniformly to obtain graphene modified polyurethane coating; Step five: Preparation of anti-permeation automobile paint surface protection film: epoxy resin modified polyurethane coating was coated on one side of the transparent base film, once heated and cured at 110℃ for 5min, annealed at 70℃ for 1h to form a first coating; graphene modified polyurethane coating was further coated on the same side, twice heated and cured at 120℃ for 3min, treated with ultraviolet light with power of 600W for 8min, repeated three times with interval of 5min each time, dried to form a second coating; to obtain anti-permeation automobile paint surface protection film.

[0023] Example 2: A preparation method of an anti-permeation automobile paint surface protection film, comprising the following steps: Step one: Preparation of branched epoxy resin; 16 parts of ethylene glycol diglycidyl ether and 1.6 parts of tetrabutylammonium bromide were mixed uniformly, stirred at 125℃ for 15min under nitrogen atmosphere, 2.1 parts of neopentyl glycol diglycidyl ether was added, and 4.7 parts of trimethylolpropane, 1.3 parts of pentaerythritol allyl ether were mixed uniformly and preheated to 100℃, then added into the reaction system gradually and dropwise, the dropwise time was controlled for 2h, and the stirring was continued at 160℃ for 6h to obtain branched epoxy resin; Step two: Preparation of epoxy resin modified polyurethane coating: 40 parts of polyisocyanate was added into 70 parts of polyester polyol and mixed uniformly under nitrogen atmosphere, stirred at 65℃ for 1.5h; 150 parts of solvent, 4 parts of 1,4-butanediol, 1 part of triethylene glycol, 0.05 parts of dibutyltin dilaurate were added in turn, stirred at 80℃ for 1h, 10 parts of branched epoxy resin was added, and stirred for 1.5h, 5 parts of multifunctional polyether amine was added at 50℃, mixed uniformly, to obtain epoxy resin modified polyurethane coating; Step three: Preparation of modified graphene oxide: 0.5 parts of graphene oxide was added into 55 parts of N,N-dimethylformamide and ultrasonically dispersed uniformly, 11 parts of hyperbranched polyester, 2.5 parts of hydroxypropyl methacrylate, 0.02 parts of tetrabutylammonium bromide were added, heated to reflux and stirred at 125℃ for 24h, filtered, washed and dried to obtain modified graphene oxide; Step four: Preparation of graphene modified polyurethane coating: 30 parts of polyester polyol and 30 parts of polyether polyol were mixed uniformly under nitrogen atmosphere, 40 parts of polyisocyanate was added, stirred at 65℃ for 1.5h; 200 parts of solvent, 10 parts of 1,4-butanediol, 1 part of butenediol, 0.05 parts of dibutyltin dilaurate were added in turn, stirred at 80℃ for 1h, 2 parts of modified graphene oxide was added, and stirred for 1.5h, 0.5 parts of leveling agent and 0.01 parts of azobisisobutyronitrile were added, stirred uniformly to obtain graphene modified polyurethane coating; Step five: Preparation of anti-permeation automobile paint surface protection film: epoxy resin modified polyurethane coating was coated on one side of the transparent base film, once heated and cured at 110℃ for 5min, annealed at 70℃ for 1h to form a first coating layer; graphene modified polyurethane coating was further coated on the same side, twice heated and cured at 120℃ for 3min, treated with ultraviolet light with power of 600W for 8min, repeated three times with interval of 5min each time, dried to form a second coating layer; to obtain the anti-permeation automobile paint surface protection film.

[0024] Example 3: A preparation method of an anti-permeation automobile paint surface protection film, comprising the following steps: Step one: Preparation of branched epoxy resin; 16 parts of ethylene glycol diglycidyl ether and 1.6 parts of tetrabutylammonium bromide were mixed uniformly, stirred at 125℃ for 15min under nitrogen atmosphere, 2.1 parts of neopentyl glycol diglycidyl ether was added, and 4.7 parts of trimethylolpropane and 1.3 parts of pentaerythritol allyl ether were mixed uniformly and preheated to 100℃, then added into the reaction system gradually and dropwise, the dropwise time was controlled to be 2h, and the stirring was continued at 160℃ for 6h to obtain the branched epoxy resin; Step two: preparation of epoxy resin modified polyurethane coating: under nitrogen atmosphere, 50 parts of polyisocyanate was added into 80 parts of polyester polyol and mixed uniformly, stirred at 65°C for 1.5h; 150 parts of solvent, 8 parts of 1,4-butanediol, 2 parts of triethylene glycol, 0.1 parts of dibutyltin dilaurate were added in turn, stirred at 80°C for 1h, 15 parts of branched epoxy resin was added, and the stirring was continued for 1.5h, 7 parts of multifunctional polyether amine was added at 55°C, mixed uniformly, and the epoxy resin modified polyurethane coating was obtained; Step three: preparation of modified graphene: 0.5 parts of graphene oxide was added into 55 parts of N,N-dimethylformamide and ultrasonically dispersed uniformly, 11 parts of hyperbranched polyester, 2.5 parts of hydroxypropyl methacrylate, 0.02 parts of tetrabutylammonium bromide were added, and the stirring was carried out under reflux at 125°C for 24h, then filtered, washed and dried to obtain modified graphene oxide; Step four: preparation of graphene modified polyurethane coating: under nitrogen atmosphere, 40 parts of polyester polyol and 50 parts of polyether polyol were mixed uniformly, 50 parts of polyisocyanate was added, and the stirring was carried out at 65°C for 1.5h; 200 parts of solvent, 12 parts of 1,4-butanediol, 2 parts of butenediol, 0.1 parts of dibutyltin dilaurate were added in turn, and the stirring was carried out at 80°C for 1h, 3 parts of modified graphene oxide was added, and the stirring was continued for 1.5h, 1 part of leveling agent and 0.03 parts of azobisisobutyronitrile were added, and the stirring was carried out uniformly to obtain graphene modified polyurethane coating; Step five: preparation of anti-permeation automobile paint surface protection film: the epoxy resin modified polyurethane coating was coated on one side of the transparent base film, and the first coating layer was formed by one-time heating and curing at 110°C for 5min and annealing at 70°C for 1h; the graphene modified polyurethane coating was further coated on the same side, and the second coating layer was formed by twice heating and curing at 120°C for 3min, ultraviolet light treatment with power of 600W for 8min, repeated three times with interval of 5min each time, and drying; and the anti-permeation automobile paint surface protection film was obtained.

[0025] Comparative example 1: based on example 1, the process for preparing epoxy resin modified polyurethane coating was replaced by market-purchased E51 epoxy resin, and the rest of the process was unchanged, as follows: Step one: preparation of epoxy resin modified polyurethane coating: under nitrogen atmosphere, 45 parts of polyisocyanate was added into 75 parts of polyester polyol and mixed uniformly, stirred at 65°C for 1.5h; 150 parts of solvent, 6 parts of 1,4-butanediol, 1.5 parts of triethylene glycol, 0.05 parts of dibutyltin dilaurate were added in turn, stirred at 80°C for 1h, 12 parts of E51 epoxy resin was added, and the stirring was continued for 1.5h, 6 parts of multifunctional polyether amine was added at 55°C, mixed uniformly, and the epoxy resin modified polyurethane coating was obtained; Step two: preparation of modified graphene: 0.5 parts of graphene oxide was added into 55 parts of N,N-dimethylformamide and uniformly dispersed by ultrasonic, 11 parts of hyperbranched polyester, 2.5 parts of hydroxypropyl methacrylate, 0.02 parts of tetrabutylammonium bromide were added, and the reaction was stirred at 125℃ under reflux for 24h, then filtered, washed and dried to obtain modified graphene oxide; Step three: preparation of graphene modified polyurethane coating: 35 parts of polyester polyol and 40 parts of polyether polyol were mixed uniformly under nitrogen atmosphere, 45 parts of polyisocyanate was added and stirred at 65℃ for 1.5h; 200 parts of solvent, 11 parts of 1,4-butanediol, 1.5 parts of butenediol, 0.05 parts of dibutyltin dilaurate were added in turn and stirred at 80℃ for 1h, 2.5 parts of modified graphene oxide was added and continued to stir for 1.5h, 0.5 parts of leveling agent and 0.01 parts of azobisisobutyronitrile were added and stirred uniformly to obtain graphene modified polyurethane coating; Step four: preparation of anti-permeation automobile paint surface protection film: the epoxy resin modified polyurethane coating was coated on one side of the transparent base film, and was once heated and cured at 110℃ for 5min, and then was annealed at 70℃ for 1h to form a first coating layer; the graphene modified polyurethane coating was further coated on the same side, and was twice heated and cured at 120℃ for 3min, and then was treated by ultraviolet light with a power of 600W for 8min, which was repeated for three times with an interval of 5min each time, and then was dried to form a second coating layer; thus an anti-permeation automobile paint surface protection film was obtained.

[0026] Comparative example 2: based on example 1, the molecular weight of hyperbranched polyester was increased to 4000 in the preparation process of modified graphene, and the rest of the process was unchanged, as follows: Step one: preparation of branched epoxy resin: 16 parts of ethylene glycol diglycidyl ether and 1.6 parts of tetrabutylammonium bromide were mixed uniformly under nitrogen atmosphere, and then 2.1 parts of neopentyl glycol diglycidyl ether was added and stirred at 125℃ for 15min; 4.7 parts of trimethylolpropane and 1.3 parts of pentaerythritol allyl ether were mixed uniformly and preheated to 100℃, and then were added into the reaction system by dropwise addition with a dropwise addition time of 2h; the reaction was continued to be stirred at 160℃ for 6h to obtain branched epoxy resin; Step two: preparation of epoxy resin modified polyurethane coating: 45 parts of polyisocyanate was added into 75 parts of polyester polyol and mixed uniformly under nitrogen atmosphere, and then was stirred at 65℃ for 1.5h; 150 parts of solvent, 6 parts of 1,4-butanediol, 1.5 parts of triethylene glycol, 0.05 parts of dibutyltin dilaurate were added in turn and stirred at 80℃ for 1h; 12 parts of branched epoxy resin was added and continued to be stirred for 1.5h; 6 parts of multifunctional polyether amine was added at 55℃ and mixed uniformly to obtain epoxy resin modified polyurethane coating; Step three: preparation of modified graphene: 0.5 parts of graphene oxide was added into 55 parts of N,N-dimethylformamide and ultrasonically dispersed uniformly, 11 parts of hyperbranched polyester (molecular weight of 4000), 2.5 parts of hydroxypropyl methacrylate, 0.02 parts of tetrabutylammonium bromide were added, and the reaction was stirred at reflux at 125℃ for 24h, filtered, washed and dried to obtain modified graphene oxide; Step four: preparation of graphene modified polyurethane coating: 35 parts of polyester polyol and 40 parts of polyether polyol were mixed uniformly under nitrogen atmosphere, 45 parts of polyisocyanate was added and stirred at 65℃ for 1.5h; 200 parts of solvent, 11 parts of 1,4-butanediol, 1.5 parts of butenediol, 0.05 parts of dibutyltin dilaurate were added in turn and stirred at 80℃ for 1h, 2.5 parts of modified graphene oxide was added and stirred for 1.5h, 0.5 parts of leveling agent and 0.01 parts of azobisisobutyronitrile were added and stirred uniformly to obtain graphene modified polyurethane coating; Step five: preparation of anti-permeation automobile paint surface protection film: epoxy resin modified polyurethane coating was coated on one side of the transparent base film, and was once heated and cured at 110℃ for 5min and annealed at 70℃ for 1h to form a first coating layer; graphene modified polyurethane coating was further coated on the same side, and was twice heated and cured at 120℃ for 3min, treated with ultraviolet light with power of 600W for 8min, repeated three times with interval of 5min each time, and dried to form a second coating layer; thus an anti-permeation automobile paint surface protection film was obtained.

[0027] Comparative example 3: based on example 1, without ultraviolet light treatment, and the rest of the process remained unchanged, as follows: Step one: preparation of branched epoxy resin: 16 parts of ethylene glycol diglycidyl ether and 1.6 parts of tetrabutylammonium bromide were mixed uniformly under nitrogen atmosphere, 2.1 parts of neopentyl glycol diglycidyl ether was added and stirred at 125℃ for 15min, 4.7 parts of trimethylolpropane and 1.3 parts of pentaerythritol allyl ether were mixed uniformly and preheated to 100℃, then added into the reaction system gradually and dropwisely, the dropwise adding time was controlled to be 2h, and the reaction was continued to be stirred at 160℃ for 6h to obtain branched epoxy resin; Step two: preparation of epoxy resin modified polyurethane coating: 45 parts of polyisocyanate was added into 75 parts of polyester polyol and mixed uniformly under nitrogen atmosphere, and stirred at 65℃ for 1.5h; 150 parts of solvent, 6 parts of 1,4-butanediol, 1.5 parts of triethylene glycol and 0.05 parts of dibutyltin dilaurate were added in turn and stirred at 80℃ for 1h, 12 parts of branched epoxy resin was added and stirred for 1.5h, 6 parts of multifunctional polyether amine was added at 55℃ and mixed uniformly to obtain epoxy resin modified polyurethane coating; Step three: preparation of modified graphene: 0.5 parts of graphene oxide was added into 55 parts of N,N-dimethylformamide and uniformly dispersed by ultrasonic, 11 parts of hyperbranched polyester, 2.5 parts of hydroxypropyl methacrylate, 0.02 parts of tetrabutylammonium bromide were added, and the reaction was stirred at 125℃ under reflux for 24h, filtered, washed and dried to obtain modified graphene oxide; Step four: preparation of graphene modified polyurethane coating: 35 parts of polyester polyol and 40 parts of polyether polyol were mixed uniformly under nitrogen atmosphere, 45 parts of polyisocyanate was added and stirred at 65℃ for 1.5h; 200 parts of solvent, 11 parts of 1,4-butanediol, 1.5 parts of butenediol, 0.05 parts of dibutyltin dilaurate were added in turn and stirred at 80℃ for 1h, 2.5 parts of modified graphene oxide was added and stirred for 1.5h, 0.5 parts of leveling agent and 0.01 parts of azobisisobutyronitrile were added and stirred uniformly to obtain graphene modified polyurethane coating; Step five: preparation of anti-permeation automobile paint surface protection film: epoxy resin modified polyurethane coating was coated on one side of the transparent base film, and was once heated and cured at 110℃ for 5min, and was annealed at 70℃ for 1h to form a first coating layer; graphene modified polyurethane coating was further coated on the same side, and was twice heated and cured at 120℃ for 3min, and was dried to form a second coating layer; an anti-permeation automobile paint surface protection film was obtained.

[0028] Comparative example 4: based on example 1, without adding modified graphene, and the rest of the process remained the same, as follows: Step one: preparation of branched epoxy resin: 16 parts of ethylene glycol diglycidyl ether and 1.6 parts of tetrabutylammonium bromide were mixed uniformly, and under nitrogen atmosphere, 2.1 parts of neopentyl glycol diglycidyl ether was added and stirred at 125℃ for 15min, 4.7 parts of trimethylolpropane and 1.3 parts of pentaerythritol allyl ether were mixed uniformly and preheated to 100℃, then were added into the reaction system by dropwise addition, and the dropwise addition time was controlled for 2h, and the reaction was continued to stir at 160℃ for 6h to obtain branched epoxy resin; Step two: preparation of epoxy resin modified polyurethane coating: 45 parts of polyisocyanate was added into 75 parts of polyester polyol and mixed uniformly under nitrogen atmosphere, and stirred at 65℃ for 1.5h; 150 parts of solvent, 6 parts of 1,4-butanediol, 1.5 parts of triethylene glycol, 0.05 parts of dibutyltin dilaurate were added in turn and stirred at 80℃ for 1h, 12 parts of branched epoxy resin was added and stirred for 1.5h, 6 parts of multifunctional polyether amine was added at 55℃ and mixed uniformly to obtain epoxy resin modified polyurethane coating; Step three: preparation of modified polyurethane coating A: under nitrogen atmosphere, 35 parts of polyester polyol and 40 parts of polyether polyol were mixed uniformly, 45 parts of polyisocyanate was added, and stirred at 65℃ for 1.5h; 200 parts of solvent, 11 parts of 1,4-butanediol, 1.5 parts of butenediol, 0.05 parts of dibutyltin dilaurate were added in turn, stirred at 80℃ for 1h, continued to stir for 1.5h, 0.5 parts of leveling agent and 0.01 parts of azobisisobutyronitrile were added, stirred uniformly, and modified polyurethane coating A was obtained; Step four: preparation of anti-permeation automobile paint surface protection film: coating epoxy resin modified polyurethane coating on one side of the transparent base film, once heating and curing at 110℃ for 5min, annealing at 70℃ for 1h, forming a first coating; further coating modified polyurethane coating A on the side, twice heating and curing at 120℃ for 3min, treating with ultraviolet light with power of 600W for 8min, repeating three times with interval of 5min each time, drying, forming a second coating; obtaining anti-permeation automobile paint surface protection film.

[0029] Performance test: the samples prepared in each example were tested in turn as follows: (1) the transmittance of the samples of each example and the comparative examples was tested according to GB / T2410-2008; (2) the samples of each example and the comparative examples were pasted on the car paint plate, and the protective film was repeatedly scraped with a copper brush for 10 times, and the surface condition of the protective film was observed; (3) the tensile strength of each example and the comparative examples was measured according to GB1040-79; (4) the samples of each example and the comparative examples were pasted on the car paint plate, and a drop of branded carburetor cleaner (B-1091) was added, and the samples were observed for damage after standing for 5min to test the anti-permeability; the experimental data is shown in Table 1.

[0030] Table 1

[0031] Conclusion: from Table 1, it can be seen that the present application has excellent light transmittance, wear resistance and tensile strength, and the protective film prepared by the present application has excellent anti-permeability without damage after the cleaner treatment, and the protective film prepared by the present application has excellent wear resistance, tensile strength and anti-permeability while ensuring the light transmittance, thereby having excellent protection effect.

[0032] In Comparative Example 1, the crosslinking density and the tensile strength were reduced due to the use of market-purchased E51 epoxy resin; in Comparative Example 2, the light transmittance was reduced due to the increase of the molecular weight of the hyperbranched polyester and the agglomeration; in Comparative Example 3, the crosslinking density was reduced due to the lack of ultraviolet initiation and the reduced rigidity of the reduced graphene oxide; in Comparative Example 4, the wear resistance and the anti-permeability were reduced due to the lack of modified graphene.

[0033] Finally, it should be noted that the above only describes the preferred embodiments of the present application and is not intended to limit the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art will appreciate that the technical solutions described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalent ones. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A permeation resistant automotive finish protection film, characterized by: The anti-permeation automobile paint surface protection film comprises a transparent base film, and a first coating layer and a second coating layer arranged on the surface of the base film in sequence; the first coating layer is formed by an epoxy resin modified polyurethane coating, and the second coating layer is formed by a graphene modified polyurethane coating. The epoxy resin modified polyurethane coating comprises the following raw materials in parts by weight: 40-50 parts of polyisocyanate, 70-80 parts of polyester polyol, 150 parts of solvent, 4-8 parts of 1,4-butanediol, 1-2 parts of triethylene glycol, 0.05-0.1 parts of dibutyltin dilaurate, 10-15 parts of branched epoxy resin, and 5-7 parts of multifunctional polyether amine.

2. A permeation resistant automotive paint finish protective film according to claim 1, characterized in that: The preparation of the epoxy resin modified polyurethane coating comprises the following process: under a nitrogen atmosphere, the polyisocyanate is added to the polyester polyol and mixed uniformly, and stirred at 60-70 DEG C for 1-2 h; the solvent, 1,4-butanediol, triethylene glycol, and dibutyltin dilaurate are sequentially added, and stirred at 75-85 DEG C for 1-1.5 h, the branched epoxy resin is added, and continues to be stirred for 1-2 h, the multifunctional polyether amine is added at 50-55 DEG C, and mixed uniformly to obtain the epoxy resin modified polyurethane coating.

3. A permeation resistant automotive paint film protection film according to claim 1, characterized in that: The preparation method of the branched epoxy resin comprises the following process: ethylene glycol diglycidyl ether and tetrabutylammonium bromide are mixed uniformly, under a nitrogen atmosphere, stirred at 125-130 DEG C for 10-15 min, neopentyl glycol diglycidyl ether is added, and trimethylolpropane and pentaerythritol allyl ether are mixed uniformly and preheated to 100 DEG C, then gradually added dropwise into the reaction system, the dropping time is controlled to be 2 h, and continues to be stirred at 155-165 DEG C for 6-8 h to obtain the branched epoxy resin.

4. A permeation resistant automotive paint finish protective film according to claim 3, characterized in that: The branched epoxy resin comprises the following raw materials in mass parts: 15-17 parts of ethylene glycol diglycidyl ether, 1.5-1.7 parts of tetrabutylammonium bromide, 2-2.2 parts of neopentyl glycol diglycidyl ether, 4.6-4.8 parts of trimethylolpropane, and 1.2-1.4 parts of pentaerythritol allyl ether.

5. A permeation resistant automotive paint film protection film according to claim 1, characterized in that: The graphene modified polyurethane coating comprises the following raw materials in mass parts: 30-40 parts of polyester polyol, 30-50 parts of polyether polyol, 40-50 parts of polyisocyanate, 200 parts of solvent, 10-12 parts of 1,4-butanediol, 1-2 parts of butenediol, 0.05-0.1 parts of dibutyltin dilaurate, 2-3 parts of modified graphene oxide, 0.5-1 parts of leveling agent, and 0.01-0.03 parts of azobisisobutyronitrile.

6. A permeation resistant automotive paint finish protective film according to claim 5, characterized in that: The preparation method of the graphene modified polyurethane coating comprises the following process: under a nitrogen atmosphere, the polyester polyol and the polyether polyol are mixed uniformly, and the polyisocyanate is added, and stirred at 60-70 DEG C for 1-2 h; the solvent, 1,4-butanediol, butenediol, and dibutyltin dilaurate are sequentially added, and stirred at 75-85 DEG C for 1-1.5 h, the modified graphene oxide is added, and continues to be stirred for 1-2 h, the leveling agent and azobisisobutyronitrile are added, and stirred uniformly to obtain the graphene modified polyurethane coating.

7. A permeation resistant automotive paint film protection film according to claim 5, characterized in that: The preparation method of the modified graphene oxide comprises the following steps: uniformly dispersing graphene oxide in N,N-dimethylformamide by ultrasonic dispersion, adding hyperbranched polyester, hydroxypropyl methacrylate and tetrabutylammonium bromide, heating and refluxing at 120-130 DEG C for 20-24 h, filtering, washing and drying to obtain the modified graphene oxide. The modified graphene oxide comprises the following raw materials in parts by mass: 0.4-0.6 parts of graphene oxide, 50-60 parts of N,N-dimethylformamide, 10-12 parts of hyperbranched polyester, 2-3 parts of hydroxypropyl methacrylate and 0.02-0.03 parts of tetrabutylammonium bromide.

8. A permeation resistant automotive paint film protection film according to claim 7, characterized in that: The hyperbranched polyester has a molecular weight of 1500-2000.

9. The method of claim 1 to 8, characterized in that: The method comprises the following steps: coating epoxy resin modified polyurethane paint on one side of a transparent base film, once heating and curing, annealing to form a first coating layer; further coating graphene modified polyurethane paint on the side, twice heating and curing, ultraviolet light irradiation and drying to form a second coating layer; obtaining an anti-permeation automobile paint surface protection film.

10. A method of preparing a permeation resistant automotive paint film protection film according to claim 9, characterized in that: In the process of heating and curing, the temperature is 100-120 DEG C and the time is 4-6 min; in the process of annealing, the temperature is 65-75 DEG C and the time is 1-1.5 h; in the process of twice heating and curing, the temperature is 110-130 DEG C and the time is 2-5 min; in the process of ultraviolet light irradiation, the power is 600-800 W and the time is 5-10 min, repeated three times with an interval of 4-5 min; The thickness of the first coating layer is 100-150 microns; The thickness of the second coating layer is 15-30 microns.

Images