A fluorine-free high weather-resistant polyethylene naphthalate film and its preparation method

Abstract

The invention discloses a fluorine-free high-weather-resistant polyethylene naphthalate film and a preparation method thereof. PEN resin is hot-pressed and then quenched to obtain a PEN film; by weight, 0.05-5 parts of nano-silicon dioxide particles, 5-10 parts of methyl methacrylate, 1-10 parts of butyl acrylate, 1-10 parts of acrylic acid, 1-20 parts of 5-(4-(2-hydroxybenzoyl)phenyl)pentyl acrylate, 1-5 parts of KH-570, 0.01-0.1 parts of an oil-soluble free radical initiator and 60-90 parts of a solvent are added to obtain a weather-resistant coating; the PEN base film is immersed in the weather-resistant coating and baked to obtain a fluorine-free high-weather-resistant PEN film. The high-weather-resistant PEN film has excellent resistance to ultraviolet degradation, can meet the use requirements in harsh environments such as strong outdoor ultraviolet rays, high heat and high humidity, and has the advantages of being fluorine-free, having good insulation and excellent barrier properties.

Description

Technical Field

[0001] The invention relates to a film material applied in the field of solar back panels, and in particular to a fluorine-free high-weather-resistant polyethylene naphthalate film and a preparation method thereof. Background Art

[0002] The solar backsheet is a photovoltaic packaging material located on the back of the solar cell module. In outdoor environments, it is mainly used to protect the solar cell module from the erosion of the packaging film, battery cells and other materials by environmental factors such as light, humidity and heat, and plays a role in weather-resistant insulation protection. Temperature and ultraviolet radiation may cause the chemical bonds of the matrix to break (i.e., the main CC chain to break), leading to light / thermal oxidation and cracking of the material, or causing polymer post-curing. If the backsheet material fails, the packaging material inside the module will be directly exposed to the harsh outdoor environment, causing hydrolysis of the packaging material, corrosion of the battery and welding strip, and delamination, etc., which will quickly reduce the power output and service life of the module. In severe cases, it will also cause the insulation failure of the module, which will then cause fires and casualties. Therefore, its weather resistance should be improved.

[0003] At present, most of the backsheets used in the market are made of fluorine-containing materials and polyethylene terephthalate (PET). The bond energy of the CF bond is 485kJ / mol, which is stable and not easily damaged by ultraviolet rays. It has excellent weather resistance. However, due to the high price and the great harm of fluorine to the environment, the recycling cost is high. Therefore, it is very important to develop a fluorine-free solar backsheet. Summary of the invention

[0004] To solve the problems in the prior art, the present invention aims to provide a fluorine-free highly weather-resistant polyethylene naphthalate film and a preparation method thereof. The solar back panel prepared by the method has strong ultraviolet absorption and scattering capabilities and good weather resistance.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] A method for preparing a fluorine-free high-weather-resistant polyethylene naphthalate film comprises the following steps:

[0007] The PEN resin is hot pressed and then quenched to obtain a PEN film;

[0008] By weight, 0.05-5 parts of nano-silica particles, 5-10 parts of methyl methacrylate, 1-10 parts of butyl acrylate, 1-10 parts of acrylic acid, 1-20 parts of 5-(4-(2-hydroxybenzoyl)phenyl)pentyl acrylate, 1-5 parts of KH-570, 0.01-0.1 parts of an oil-soluble free radical initiator and 60-90 parts of a solvent are mixed to obtain a weather-resistant coating;

[0009] Immerse the PEN base film in the weather-resistant coating and bake it to obtain a fluorine-free high-weather-resistant PEN film.

[0010] Furthermore, the intrinsic viscosity of the PEN resin is 0.60 dL / g - 1.50 dL / g, and the thickness of the PEN film is 25 - 200 μm.

[0011] Furthermore, the temperature of hot pressing is 260 - 300 °C, and the pressure of hot pressing is 20 - 200 Mpa.

[0012] Furthermore, the temperature of the free radical polymerization reaction is 110 - 140 °C, and the time is 2 - 6 h.

[0013] Furthermore, the free radical polymerization reaction is carried out in a light-shielded environment.

[0014] Furthermore, the diameter of the nano-silica is 10 - 1000 nm.

[0015] Furthermore, the oil-soluble radical initiator is one or two of benzoyl peroxide, di-tert-butyl peroxide and azobisisobutyronitrile.

[0016] Furthermore, the solvent is one or two of benzene, toluene, xylene, ethyl acetate, acetone and dimethylformamide.

[0017] Furthermore, the baking temperature is 110 - 150 °C, and the time is 1 - 10 min.

[0018] A fluorine-free high-weather-resistant polyethylene naphthalate film prepared by the preparation method as described above, the thickness of the film is 25 - 200 μm, the tensile strength is 158 - 168 MPa, and the weather resistance is 50 - 53%.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] In the present invention, methacrylic acid, methyl methacrylate, butyl acrylate and 5-(4-(2-hydroxybenzoyl)phenyl)pentyl acrylate are used as acrylic resins. 5-(4-(2-hydroxybenzoyl)phenyl)pentyl acrylate can form intramolecular hydrogen bonds. After absorbing ultraviolet light, it causes the transfer of intramolecular hydrogen bonds or the isomerization of double bonds. This tautomer is unstable and can safely convert the excess energy into heat energy and return to a more stable ground state. Therefore, it has good ultraviolet absorption ability. By introducing Si-O bonds through KH-570, nano-silica can be evenly dispersed in the resin, playing a role in blocking ultraviolet light. In the present invention, due to the extremely strong ultraviolet absorption and infrared reflection characteristics of nano-silica, the ultraviolet absorption rate for ultraviolet light within 400 nm wavelength can be as high as over 70%, and the infrared light reflectivity for infrared light outside 800 nm wavelength also reaches over 70%. Therefore, nano-silica can play an effective shielding role in the film, achieving the purpose of anti-ultraviolet aging. However, because the surface of nano-silica has active hydroxyl groups, it is prone to agglomeration, difficult to be evenly dispersed in organic matter and polymers, and difficult to form coupling bonds with polymers. Modify nano-silica with the silane coupling agent KH-570. Use the silanol groups generated by the hydrolysis reaction of the silane coupling agent. One end condenses with the hydroxyl groups on the surface of nano-silica to form silicon-oxygen bonds, and the other end connects to the matrix, effectively preventing agglomeration between particles and improving its dispersibility. In the present invention, in addition to improving the dispersibility of nano-silica, the silane coupling agent KH570 can also participate in the polymerization reaction as a matrix due to its own double bond, playing a role in anti-ultraviolet. The present invention selects acrylic resin as the matrix, and by adding modified nano-silica and 5-(4-(2-hydroxybenzoyl)phenyl)pentyl acrylate monomer during the polymerization process, a fluorine-free high weather resistance coating is prepared by utilizing their synergistic effect. Coating it on the surface of PEN base film to prepare a fluorine-free high weather resistance PEN film. The PEN film used in the present invention does not contain fluorine, has a lower cost, is environmentally friendly, has excellent weather resistance, and has good application prospects in solar backsheets. Compared with the traditional PET base film, the PEN resin base film has stronger ultraviolet absorption performance and weather resistance due to the naphthalene ring structure in the molecular chain, and is thus more suitable for outdoor environments with strong ultraviolet light and high temperature and high humidity. Description of the Drawings

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below:

[0022] Figure 1 It is the structural formula of the acrylic resin in the present invention.

[0023] Figure 2It is a comparison chart of the ultraviolet transmittance of PEN backplane and PET backplane. Detailed implementation mode

[0024] To facilitate the understanding of the present invention, the present invention will be described more comprehensively below with reference to the relevant drawings. The preferred embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided to make the disclosure of the present invention more thorough and comprehensive.

[0025] For those not specified in the examples, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. For the reagents or instruments not specified in the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0026] The polyethylene naphthalate (PEN) resin has a higher ultraviolet absorption rate than the PET resin, and can block more ultraviolet rays to a certain extent. The naphthalene ring in the molecular chain structure of the polyethylene naphthalate makes the small molecule barrier property of the resin stronger. Under the condition of having a pressure difference, small molecules are not easy to penetrate, which is beneficial to the safety performance of the battery pack. The weather resistance of the PEN resin itself can enable it not to use fluorine-containing coatings or use less fluorine-containing coatings, greatly reducing costs.

[0027] A preparation method of a fluorine-free and highly weather-resistant polyethylene naphthalate film (PEN) of the present invention includes the following steps:

[0028] (1) The method for preparing the PEN base film is: hot-pressing and then quenching the PEN resin under high temperature and high pressure conditions to obtain a PEN film.

[0029] The intrinsic viscosity of the PEN resin is 0.60 dL / g - 1.50 dL / g, the hot-pressing temperature is 260 - 300 °C, the pressure of the hot press is 20 - 200 Mpa, and the thickness of the PEN film is 25 - 200 μm.

[0030] (2) The method for preparing the weather-resistant coating is: by mass, 0.05 - 5 parts of nano-silica particles, 5 - 10 parts of methyl methacrylate, 1 - 10 parts of butyl acrylate, 1 - 10 parts of acrylic acid, 1 - 20 parts of 5-(4-(2-hydroxybenzoyl)phenyl)pentyl acrylate acrylate, 1 - 5 parts of KH-570 monomer, 0.01 - 0.1 part of an oil-soluble free radical initiator and 60 - 90 parts of a solvent are reacted under the condition of 110 - 140 °C for 2 - 6 h in a light-shielded environment to carry out free radical polymerization to obtain a weather-resistant coating.

[0031] Among them, the diameter of the nano-silica is 10 - 1000 nm.

[0032] The oil-soluble free radical initiator is one or two of benzoyl peroxide (BPO), di-tert-butyl peroxide and azodiisobutyronitrile.

[0033] The solvent is a mixed solvent of one or two of benzene, toluene, xylene, ethyl acetate, acetone and dimethylformamide.

[0034] (3) The coating process is as follows: Immerse the PEN-based film in the weather-resistant coating, and then bake it to obtain a fluorine-free high-weather-resistant PEN film. The total thickness of the fluorine-free high-weather-resistant PEN film is 25 - 200 μm; the thickness of the coating layer on the fluorine-free high-weather-resistant PEN film is 1 - 10 μm, and the coating layer is acrylic resin. For the structure of the acrylic resin, see Figure 1 .

[0035] Among them, the coating baking temperature is 110 - 150 °C, the baking time is 1 - 5 min, the tensile strength of the prepared fluorine-free high-weather-resistant PEN film is 158 - 168 MPa, and the weather resistance is 50 - 53%.

[0036] The technical solution of the present invention will be described in detail below through specific examples.

[0037] Example 1

[0038] This example provides a fluorine-free high-weather-resistant PEN film, which is composed of a base film and a weather-resistant coating. The preparation method is as follows:

[0039] (1) Take 5 g of PEN resin and place it on a hot press. Under the conditions of 265 °C and 100 Mpa, hot press for 2 min, and then quickly place it in cold water to cool to obtain an amorphous PEN base film with a thickness of 50 μm for standby.

[0040] (2) Weigh 10 g of methacrylic acid, 8 g of methyl methacrylate, 8 g of butyl acrylate and 7 g of 5-(4-(2-hydroxybenzoyl)phenyl)pentyl acrylate, 1 g of silane coupling agent KH570, 70 g of xylene, and 0.1 g of BPO initiator into a flask. React at 130 °C for 4 h in a light-shielded environment. Then place 4 g of silicon dioxide particles with a diameter of 50 nm into the flask, set the stirring rate to 600 r / min, cool down after reacting for 1 h, and stop the reaction to obtain a coating solution for standby.

[0041] (3) Immerse the PEN base film in the coating solution, and then place it in an oven at 130 °C and bake for 2 min to obtain a fluorine-free high-weather-resistant PEN film.

[0042] To evaluate the specific technical effects of the weather-resistant PEN film of the present invention, the weather-resistant PEN films in the examples and comparative examples of the present invention were subjected to performance tests. The test methods are as follows: The tensile strength was tested according to GB / T 13022-1991, the test speed was 10±2 mm / min, the test temperature was 23°C, the test sample was a type-IV long strip sample, and a universal testing machine was used for testing; for weather resistance, the products of each example were placed in an environment of 120°C, 100% RH, and 2 atm for 48 h respectively. After cooling to room temperature, the tensile strength of the treated sample was tested. The weather resistance was measured by the retention rate of the tensile strength. The larger the value, the better the weather resistance. The retention rate of the tensile strength = the tensile strength after treatment / the tensile strength before treatment × 100%. The tensile strength before and after treatment was tested according to GB / T 13022-1991.

[0043] The test results are shown in the following table:

[0044] Item Tensile strength Weather resistance Unit MPa ％ Example 1 168 52

[0045] See Figure 2 , it can be seen that the PEN film has a better absorption effect on ultraviolet light than the PET film, indicating that it has good weather resistance.

[0046] Example 2

[0047] This example provides a fluorine-free high weather-resistant PEN film, which consists of a base film and a weather-resistant coating. The preparation method is as follows:

[0048] (1) Take 5 g of PEN resin and place it on a hot press. Under the conditions of 280°C and 100 Mpa, hot press for 2 min and then quickly place it in cold water for cooling to obtain an amorphous PEN base film with a thickness of 50 μm for standby.

[0049] (2) Weigh 10 g of methacrylic acid, 8 g of methyl methacrylate, 8 g of butyl acrylate, 7 g of 5-(4-(2-hydroxybenzoyl)phenyl)pentyl acrylate, 1 g of silane coupling agent KH570, 70 g of xylene, and 0.1 g of BPO initiator into a flask. React at 130°C for 4 h in a light-shielded environment. Then place 4 g of silicon dioxide particles with a diameter of 50 nm into the flask, set the stirring rate to 600 r / min, cool down after reacting for 1 h, and stop the reaction to obtain a coating solution for standby.

[0050] (3) Immerse the PEN base film in the coating solution and then bake it in an oven at 130°C for 2 min to obtain a fluorine-free high weather-resistant PEN film.

[0051] According to the test method provided in Example 1, the weather resistance of the obtained weather-resistant film was tested. The results are shown in the following table:

[0052] Item Tensile strength Weather resistance Unit MPa ％ Example 2 164 51

[0053] Example 3

[0054] This example provides a fluorine-free highly weather-resistant PEN film, which consists of a base film and a weather-resistant coating. The preparation method is as follows:

[0055] (1) Take 5 g of PEN resin and place it on a hot press. Heat-press it at 265 °C under a condition of 100 Mpa for 5 min, and then quickly place it in cold water for cooling to obtain an amorphous PEN base film with a thickness of 50 μm for standby.

[0056] (2) Weigh 10 g of methacrylic acid, 8 g of methyl methacrylate, 8 g of butyl acrylate, 7 g of 5-(4-(2-hydroxybenzoyl)phenyl)pentyl acrylate, 1 g of silane coupling agent KH570, 70 g of xylene, and 0.1 g of BPO initiator into a flask. React under a condition of 130 °C for 4 h in a light-shielded environment. Then place 4 g of silica particles with a diameter of 50 nm into the flask, set the stirring rate to 600 r / min, cool down after reacting for 1 h, and stop the reaction to obtain a coating solution for standby.

[0057] (3) Immerse the PEN base film in the coating solution, and then bake it in an oven at 130 °C for 2 min to obtain a fluorine-free highly weather-resistant PEN film.

[0058] According to the testing method provided in Example 1, test the weather resistance of the obtained weather-resistant film. The results are shown in the following table:

[0059] Item Tensile strength Weather resistance Unit MPa ％ Example 3 162 50

[0060] Example 4

[0061] This example provides a fluorine-free highly weather-resistant PEN film, which consists of a base film and a weather-resistant coating. The preparation method is as follows:

[0062] (1) Take 5 g of PEN resin and place it on a hot press. Heat-press it at 265 °C under a condition of 100 Mpa for 2 min, and then quickly place it in cold water for cooling to obtain an amorphous PEN base film with a thickness of 50 μm for standby.

[0063] (2) Weigh 10 g of methacrylic acid, 8 g of methyl methacrylate, 8 g of butyl acrylate, 10 g of 5-(4-(2-hydroxybenzoyl)phenyl)pentyl acrylate, 1 g of silane coupling agent KH570, 70 g of xylene, and 0.1 g of BPO initiator into a flask. React under a condition of 130 °C for 4 h in a light-shielded environment. Then place 4 g of silica particles with a diameter of 50 nm into the flask, set the stirring rate to 600 r / min, cool down after reacting for 1 h, and stop the reaction to obtain a coating solution for standby.

[0064] (3) Immerse the PEN base film in the coating solution, and then place it in an oven at 130 °C and bake for 2 min to obtain a fluorine-free high weather-resistant PEN film.

[0065] According to the test method provided in Example 1, test the weather resistance of the obtained weather-resistant film, and the results are shown in the following table:

[0066] Item Tensile strength Weather resistance Unit MPa ％ Example 4 167 53

[0067] Example 5

[0068] This example provides a fluorine-free high weather-resistant PEN film, which consists of a base film and a weather-resistant coating, and its preparation method is as follows:

[0069] (1) Take 5 g of PEN resin and place it on a hot press. Under the conditions of 265 °C and 100 Mpa, hot press for 2 min and then quickly place it in cold water for cooling to obtain an amorphous PEN base film with a thickness of 50 μm for standby.

[0070] (2) Weigh 10 g of methacrylic acid, 8 g of methyl methacrylate, 8 g of butyl acrylate, 7 g of 5-(4-(2-hydroxybenzoyl)phenyl)pentyl acrylate, 1 g of silane coupling agent KH570, 70 g of xylene, and 0.1 g of BPO initiator into a flask. React under the conditions of 130 °C for 4 h in a light-shielded environment. Then place 10 g of silicon dioxide particles with a diameter of 50 nm into the flask, set the stirring rate to 600 r / min, cool down after reacting for 1 h, and stop the reaction to obtain a coating solution for standby.

[0071] (3) Immerse the PEN base film in the coating solution, and then place it in an oven at 130 °C and bake for 2 min to obtain a fluorine-free high weather-resistant PEN film.

[0072] According to the test method provided in Example 1, test the weather resistance of the obtained weather-resistant film, and the results are shown in the following table:

[0073]

[0074]

[0075] Example 6

[0076] This example provides a fluorine-free high weather-resistant PEN film, which consists of a base film and a weather-resistant coating, and its preparation method is as follows:

[0077] (1) Take 5 g of PEN resin and place it on a hot press. Under the conditions of 265 °C and 100 Mpa, hot press for 2 min and then quickly place it in cold water for cooling to obtain an amorphous PEN base film with a thickness of 50 μm for standby.

[0078] (2) Weigh 10 g of methacrylic acid, 8 g of methyl methacrylate, 8 g of butyl acrylate, and 7 g of 5-(4-(2-hydroxybenzoyl)phenyl)pentyl acrylate. Add 1 g of silane coupling agent KH570, 70 g of xylene, and 0.1 g of BPO initiator to a flask. React for 4 h at 130 °C in a light-shielded environment. Then, place 4 g of silica particles with a diameter of 100 nm into the flask. Set the stirring rate to 600 r / min. After reacting for 1 h, cool down the temperature and stop the reaction to obtain a coating solution for standby.

[0079] (3) Immerse the PEN-based film in the coating solution, and then bake it in an oven at 130 °C for 2 min to obtain a fluorine-free highly weather-resistant PEN film.

[0080] According to the testing method provided in Example 1, test the weather resistance of the obtained weather-resistant film. The results are shown in the following table:

[0081] Item Tensile strength Weather resistance Unit MPa ％ Example 6 124 51

[0082] Example 7

[0083] This example provides a fluorine-free highly weather-resistant PEN film, which consists of a base film and a weather-resistant coating. The preparation method is as follows:

[0084] (1) Take 5 g of PEN resin and place it on a hot press. Heat-press it at 265 °C under a pressure of 100 Mpa for 2 min, and then quickly place it in cold water for cooling to obtain an amorphous PEN base film with a thickness of 50 μm for standby.

[0085] (2) Weigh 10 g of methacrylic acid, 8 g of methyl methacrylate, 8 g of butyl acrylate, and 7 g of 5-(4-(2-hydroxybenzoyl)phenyl)pentyl acrylate. Add 1 g of silane coupling agent KH570, 70 g of xylene, and 0.1 g of BPO initiator to a flask. React for 4 h at 130 °C in a light-shielded environment. Then, place 4 g of silica particles with a diameter of 50 nm into the flask. Set the stirring rate to 600 r / min. After reacting for 1 h, cool down the temperature and stop the reaction to obtain a coating solution for standby.

[0086] (3) Immerse the PEN-based film in the coating solution, and then bake it in an oven at 150 °C for 2 min to obtain a fluorine-free highly weather-resistant PEN film.

[0087] According to the testing method provided in Example 1, test the weather resistance of the obtained weather-resistant film. The results are shown in the following table:

[0088] Item Tensile strength Weather resistance Unit MPa ％ Example 7 162 52

[0089] Example 8

[0090] This embodiment provides a fluorine-free and highly weather-resistant PEN film, which consists of a base film and a weather-resistant coating. The preparation method is as follows:

[0091] (1) Take 5 g of PEN resin and place it on a hot press. Under the conditions of 265 °C and 100 Mpa, hot press for 2 min and then quickly place it in cold water for cooling to obtain an amorphous PEN base film with a thickness of 50 μm for standby.

[0092] (2) Weigh 10 g of methacrylic acid, 8 g of methyl methacrylate, 8 g of butyl acrylate, 7 g of 5-(4-(2-hydroxybenzoyl)phenyl)pentyl acrylate, 1 g of silane coupling agent KH570, 70 g of xylene, and 0.1 g of BPO initiator into a flask. React for 4 h at 130 °C in a light-shielded environment. Then place 4 g of silica particles with a diameter of 50 nm into the flask, set the stirring rate to 600 r / min, cool down after reacting for 1 h, and stop the reaction to obtain a coating solution for standby.

[0093] (3) Immerse the PEN base film in the coating solution and then bake it in an oven at 130 °C for 10 min to obtain a fluorine-free and highly weather-resistant PEN film.

[0094] According to the test method provided in Example 1, test the weather resistance of the obtained weather-resistant film. The results are shown in the following table:

[0095] Item Tensile strength Weather resistance Unit MPa ％ Example 8 158 52

[0096] Example 9

[0097] (1) Take 5 g of PEN resin and place it on a hot press. Under the conditions of 260 °C and 20 Mpa, hot press for 2 min and then quickly place it in cold water for cooling to obtain an amorphous PEN base film with a thickness of 25 μm for standby.

[0098] (2) Weigh 5 g of methacrylic acid, 10 g of methyl methacrylate, 1 g of butyl acrylate, 20 g of 5-(4-(2-hydroxybenzoyl)phenyl)pentyl acrylate, 2 g of silane coupling agent KH570, 60 g of benzene, and 0.01 g of di-tert-butyl peroxide initiator into a flask. React for 6 h at 110 °C in a light-shielded environment. Then place 0.05 g of silica particles with a diameter of 10 nm into the flask, set the stirring rate to 600 r / min, cool down after reacting for 1 h, and stop the reaction to obtain a coating solution for standby.

[0099] (3) Immerse the PEN base film in the coating solution and then bake it in an oven at 110 °C for 5 min to obtain a fluorine-free and highly weather-resistant PEN film.

[0100] Example 10

[0101] (1) Take 5 g of PEN resin and place it on a hot press. Heat press it at 300 °C under a condition of 200 Mpa for 2 min, and then quickly place it in cold water for cooling to obtain an amorphous PEN base film with a thickness of 200 μm for standby.

[0102] (2) Weigh 6 g of methacrylic acid, 5 g of methyl methacrylate, 3 g of butyl acrylate, and 1 g of 5-(4-(2-hydroxybenzoyl)phenyl)pentyl acrylate, 3 g of silane coupling agent KH570, 90 g of toluene, and 0.05 g of azobisisobutyronitrile initiator into a flask. React under a condition of 140 °C for 2 h in a light-shielded environment. Then place 5 g of silica particles with a diameter of 1000 nm into the flask, set the stirring rate to 600 r / min, cool down after reacting for 1 h, and stop the reaction to obtain a coating solution for standby.

[0103] (3) Immerse the PEN base film in the coating solution, and then bake it in an oven at 120 °C for 3 min to obtain a fluorine-free highly weather-resistant PEN film.

[0104] Example 11

[0105] (1) Take 5 g of PEN resin and place it on a hot press. Heat press it at 290 °C under a condition of 60 Mpa for 2 min, and then quickly place it in cold water for cooling to obtain an amorphous PEN base film with a thickness of 70 μm for standby.

[0106] (2) Weigh 7 g of methacrylic acid, 8 g of methyl methacrylate, 5 g of butyl acrylate, and 15 g of 5-(4-(2-hydroxybenzoyl)phenyl)pentyl acrylate, 4 g of silane coupling agent KH570, 80 g of solvent (a mixture of ethyl acetate and acetone with a mass ratio of 1:1), and 0.03 g of initiator (a mixture of BPO and di-tert-butyl peroxide with a mass ratio of 1:1) into a flask. React under a condition of 120 °C for 4 h in a light-shielded environment. Then place 2 g of silica particles with a diameter of 500 nm into the flask, set the stirring rate to 600 r / min, cool down after reacting for 1 h, and stop the reaction to obtain a coating solution for standby.

[0107] (3) Immerse the PEN base film in the coating solution, and then bake it in an oven at 140 °C for 2 min to obtain a fluorine-free highly weather-resistant PEN film.

[0108] Example 12

[0109] (1) Take 5 g of PEN resin and place it on a hot press. Heat press it at 270 °C under a condition of 150 Mpa for 2 min, and then quickly place it in cold water for cooling to obtain an amorphous PEN base film with a thickness of 150 μm for standby.

[0110] (2) Weigh 9 g of methacrylic acid, 7 g of methyl methacrylate, 8 g of butyl acrylate, and 4 g of 5-(4-(2-hydroxybenzoyl)phenyl)pentyl acrylate, 5 g of silane coupling agent KH570, 65 g of dimethylformamide, and 0.1 g of BPO initiator into a flask. React under 130 °C in a light-shielded environment for 3 h. Then, place 3 g of silica particles with a diameter of 800 nm into the flask. Set the stirring rate to 600 r / min. After reacting for 1 h, cool down the temperature and stop the reaction to obtain a coating solution for standby.

[0111] (3) Immerse the PEN-based film in the coating solution, and then bake it in an oven at 150 °C for 1 min to obtain a fluorine-free high weather-resistant PEN film.

[0112] In KH570 of the present invention, there is a double bond, which can participate in the free radical polymerization reaction. KH560 cannot, because it has no double bond and cannot participate in the reaction.

[0113] Comparative Example 1

[0114] This comparative example provides a high weather-resistant PEN film, which consists of a base film and a weather-resistant coating, but there are no nano-silica particles in it. The preparation method is as follows:

[0115] (1) Take 5 g of PEN resin and place it on a hot press. Under 280 °C and 100 Mpa, hot press for 2 min and then quickly place it in cold water for cooling to obtain an amorphous PEN base film with a thickness of 50 μm for standby.

[0116] (2) Weigh a certain amount of 10 g of methacrylic acid, 8 g of methyl methacrylate, 8 g of butyl acrylate, and 7 g of 5-(4-(2-hydroxybenzoyl)phenyl)pentyl acrylate, 1 g of silane coupling agent KH570, 70 g of xylene, and 0.1 g of BPO initiator into a flask. React under 130 °C in a light-shielded environment for 4 h and then set aside for standby.

[0117] (3) Immerse the PEN-based film in the coating solution, and then bake it in an oven at 130 °C for 2 min to obtain a fluorine-free high weather-resistant PEN film.

[0118] According to the test method provided in Example 1, test the weather resistance of the obtained weather-resistant film. The results are shown in the following table:

[0119] Item Tensile strength Weather resistance Unit MPa ％ Comparative Example 1 167 45

[0120] Comparative Example 2

[0121] This comparative example provides a high weather-resistant PEN film, which consists of a base film and a weather-resistant coating, but there is no 5-(4-(2-hydroxybenzoyl)phenyl)pentyl acrylate in it. The preparation method is as follows:

[0122] (1) Take 5 g of PEN resin and place it on a hot press. Heat-press it at 265 °C under a condition of 100 Mpa for 2 min, and then quickly place it in cold water for cooling to obtain an amorphous PEN-based film with a thickness of 50 μm for standby.

[0123] (2) Weigh 10 g of methacrylic acid, 8 g of methyl methacrylate, 8 g of butyl acrylate, 1 g of silane coupling agent KH570, 70 g of xylene, and 0.1 g of BPO initiator into a flask. React under a condition of 130 °C for 4 h in a light-shielded environment. Then place 4 g of silicon dioxide particles with a diameter of 50 nm into the flask. Set the stirring rate to 600 r / min. After reacting for 1 h, cool down and stop the reaction to obtain a coating solution for standby.

[0124] (3) Immerse the PEN-based film in the coating solution, and then bake it in an oven at 130 °C for 2 min to obtain a fluorine-free high-weather-resistant PEN film.

[0125] According to the test method provided in Example 1, test the weather resistance of the obtained weather-resistant film. The results are shown in the following table:

[0126] Item Tensile strength Weather resistance Unit MPa ％ Comparative Example 2 166 42

[0127] By comparing Comparative Example 1 with Examples 1-8 in this application, it can be seen that by introducing modified nano-silicon dioxide into the coating, the weather resistance of the PEN film is significantly improved. By comparing Comparative Example 2 with Examples 1-8 in this application, it can be seen that by introducing 5-(4-(2-hydroxybenzoyl)phenyl)pentyl acrylate monomer into the coating, the weather resistance of the PEN film is significantly improved. The present invention selects an acrylic resin as the matrix, and by adding modified nano-silicon dioxide and 5-(4-(2-hydroxybenzoyl)phenyl)pentyl acrylate monomer during the polymerization process, and utilizing the synergistic effect of the two, a fluorine-free high-weather-resistant coating is prepared, and it is coated on the surface of the PEN-based film to prepare a fluorine-free high-weather-resistant PEN film.

[0128] The fluorine-free high-weather-resistant film of the present invention is composed of a base film and a surface coating. This high-weather-resistant PEN film has excellent anti-ultraviolet degradation performance, can meet the use requirements in harsh environments such as strong ultraviolet rays, high heat, and high humidity outdoors, and has the advantages of being fluorine-free, having good insulation, and excellent barrier properties, and has industrial application prospects.

[0129] The above only illustrates the best embodiments of the present invention, but it should not be construed as a limitation to the claims. The present invention is not limited to the above embodiments, and its specific structure allows changes. Any changes made within the protection scope of the independent claims of the present invention are within the protection scope of the present invention.

[0130] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terms used herein in the specification of the present invention are for the purpose of describing particular embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

Claims

1. Preparation method of a fluorine-free and highly weather-resistant polyethylene naphthalate film, characterized in that, it comprises the following steps: Hot-press and then quenching the PEN resin to obtain a PEN film; By mass, 0.05 - 5 parts of nano-silica particles, 5 - 10 parts of methyl methacrylate, 1 - 10 parts of butyl acrylate, 1 - 10 parts of acrylic acid, 1 - 20 parts of 5-(4-(2-hydroxybenzoyl)phenyl)pentyl acrylate, 1 - 5 parts of KH-570, 0.01 - 0.1 part of an oil-soluble radical initiator and 60 - 90 parts of a solvent are reacted at 110 - 140 °C for 2 - 6 h in a light-shielded environment to carry out a radical polymerization reaction. The temperature of the radical polymerization reaction is 110 - 140 °C and the time is 2 - 6 h to obtain a weather-resistant coating; Immerse the PEN base film in the weather-resistant coating and bake to obtain a fluorine-free and highly weather-resistant PEN film.

2. The preparation method of the fluorine-free and highly weather-resistant polyethylene naphthalate film according to claim 1, characterized in that, the intrinsic viscosity of the PEN resin is 0.60 dL / g - 1.50 dL / g, and the thickness of the PEN film is 25 - 200 μm.

3. The preparation method of the fluorine-free and highly weather-resistant polyethylene naphthalate film according to claim 1, characterized in that, the temperature of the hot pressing is 260 - 300 °C, and the pressure of the hot pressing is 20 - 200 Mpa.

4. The preparation method of the fluorine-free and highly weather-resistant polyethylene naphthalate film according to claim 1, characterized in that, the radical polymerization reaction is carried out in a light-shielded environment.

5. The preparation method of the fluorine-free and highly weather-resistant polyethylene naphthalate film according to claim 1, characterized in that, the diameter of the nano-silica is 10 - 1000 nm.

6. The preparation method of the fluorine-free and highly weather-resistant polyethylene naphthalate film according to claim 1, characterized in that, the oil-soluble radical initiator is one or two of benzoyl peroxide, di-tert-butyl peroxide and azobisisobutyronitrile.

7. The preparation method of the fluorine-free and highly weather-resistant polyethylene naphthalate film according to claim 1, characterized in that, the solvent is one or two of benzene, toluene, xylene, ethyl acetate, acetone and dimethylformamide.

8. The preparation method of the fluorine-free and highly weather-resistant polyethylene naphthalate film according to claim 1, characterized in that, the baking temperature is 110 - 150 °C and the time is 1 - 10 min.

9. A fluorine-free and highly weather-resistant polyethylene naphthalate film prepared by the preparation method according to any one of claims 1 - 8, characterized in that, the thickness of the film is 25 - 200 μm, the tensile strength is 158 - 168 MPa, and the weather resistance is 50 - 53%.

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