Preparation method and application of nano-composite reinforced weather-resistant solar cell backboard polyester film

Abstract

The invention relates to a preparation method of a nano-composite reinforced weather-resistant solar cell backboard polyester film, which comprises the following steps: 1, fully and uniformly mixing polyethylene glycol terephthalate and a modifier, and carrying out melt blending in a twin-screw extruder; 2, adding a weather-resistant composition into the uniformly mixed and molten modified polyethylene glycol terephthalate, continuing to perform melt mixing in the double-screw extruder, and vacuumizing until the mixture of the weather-resistant composition and the modified polyethylene glycol terephthalate is uniformly mixed; step 3, preparing a polyester film; and drying the mixture of the weather-resistant composition and the modified polyethylene glycol terephthalate obtained in the step 2, putting the dried mixture into an extruder, carrying out transverse stretching and longitudinal stretching, carrying out heat setting at 180-220 DEG C, and carrying out rolling and slitting to obtain a finished product. The polyester film prepared by the invention has good tensile strength, weather resistance and water resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cell backsheet films, and particularly to a preparation method and application of a nano-composite reinforced weather-resistant polyester film for solar cell backsheets. Background Art

[0002] With the continuous development of the solar energy industry, people have increasingly understood the benefits of solar energy, which is of epoch-making significance for human development and solving environmental pollution problems. However, with the development of solar cells, it has been found that the protection system of solar cells in harsh environments is not perfect, resulting in an unsatisfactory working life. Therefore, the protection of solar cells is particularly important, and the research and development of solar cell backsheets are of great significance.

[0003] Since the use environment of solar cell modules is extremely harsh, the protection of solar cells is particularly important. Therefore, the research on the key protection component, the "solar cell backsheet", is of great significance. As an important encapsulation material for solar cell modules, the solar cell backsheet is composed of multiple thin film materials and can withstand various harsh outdoor environments. The solar cell backsheet generally adopts a structure of fluorine film / polyester film / fluorine film, where the polyester film provides insulation performance, water vapor barrier performance, and support, and the fluorine film material provides the performance of being resistant to long-term aging for the solar cell backsheet.

[0004] Currently, there are a wide variety of solar cell backsheets globally, with a general minimum working life of 25 years, and some even up to 40 years. According to the manufacturing process of solar cell backsheets, they can be generally divided into two types: thin film composite type and coating type, among which the thin film composite type solar cell backsheet is the leading product. Fluorine film is a key material in the composite solar cell backsheet.

[0005] Currently, the polyester film of the solar cell backsheet has problems such as poor ultraviolet blocking ability, poor water vapor barrier property, and weak self-cleaning ability. The poor weather resistance of the polyester film will directly affect the service life of the solar cell backsheet, and may even cause short circuits in solar cells in severe cases, resulting in unnecessary hazards. Summary of the Invention

[0006] The first aspect of the present invention provides a preparation method of a nano-composite reinforced weather-resistant polyester film for solar cell backsheets, comprising the following steps:

[0007] Step 1: Prepare modified polyethylene terephthalate; after thoroughly mixing polyethylene terephthalate and a modifier, conduct melt blending in a twin-screw extruder; the screw speed is (15 - 30) r / min, the melting temperature is 250 - 300 °C, and the mixing time is 3 - 5 h; the weight part of the modifier is 0.5 - 1.2.

[0008] Step 2: Add the weather resistance composition into the uniformly mixed molten modified polyethylene terephthalate, continue to carry out melt mixing in a twin-screw extruder and evacuate, the screw speed is (15 - 30) r / min, the melting temperature is 250 - 300 °C, the mixing time is 3 - 5 h, and the vacuum degree is 90 - 140 mmHg; evacuate until the mixture of the weather resistance composition and the modified polyethylene terephthalate is uniformly mixed and there are no bubbles in stirring; the weight part of the weather resistance composition is 15 - 28.

[0009] Step 3: Prepare a polyester film; dry the mixture of the weather resistance composition and the modified polyethylene terephthalate obtained in Step 2 and put it into an extruder, the extrusion temperature is 250 - 300 °C; the extruded thick sheet is transversely stretched 3 - 5 times at 80 - 100 °C, the extruded thick sheet is longitudinally stretched 3 - 5 times at 80 - 100 °C, and after transverse and longitudinal stretching, it is heat-set at 180 - 220 °C, wound and slit to obtain the finished product.

[0010] The present invention is further provided that the modifier is a composite carbon material.

[0011] The present invention is further provided that the composite carbon material is composed of carbon nanotubes and graphene according to the mass ratio of (1 - 3)∶(2 - 4).

[0012] The present invention is further provided that the weather resistance composition includes a hydrolysis-resistant agent, a water-blocking agent, an antioxidant, and an ultraviolet absorber.

[0013] The present invention is further provided that the hydrolysis-resistant agent includes one of carbodiimide polymers and multifunctional epoxy-based hydrolysis-resistant agents;

[0014] The water-blocking agent includes one of organic bentonite and ethylene-vinyl acetate copolymer;

[0015] The antioxidant includes one of hindered phenol antioxidants and phosphite antioxidants;

[0016] The ultraviolet absorber includes one of benzotriazole ultraviolet absorbers and triazine ultraviolet absorbers.

[0017] The present invention is further provided that the hydrolysis-resistant agent is a carbodiimide polymer;

[0018] The water-blocking agent is organic bentonite;

[0019] The antioxidant is the hindered phenol antioxidant 1010;

[0020] The ultraviolet absorber is the benzotriazole ultraviolet absorber UV-326.

[0021] The present invention is further configured such that the mass ratio of the hydrolysis-resistant agent, water-blocking agent, anti-aging agent, and ultraviolet absorber is (6-9):(3-6):(3-5):(2-4).

[0022] The present invention is further configured such that the mass ratio of the hydrolysis-resistant agent, water-blocking agent, anti-aging agent, and ultraviolet absorber is 7:4:4:3.

[0023] An application of a reinforced polyester film for a solar cell backsheet, characterized in that: the reinforced polyester film prepared according to the said method is applied to the solar cell backsheet.

[0024] The polyester film prepared by the preparation method of the solar cell backsheet reinforced polyester film provided by the present invention has good tensile strength, weather resistance, and water-blocking property, has good tolerance effects on environmental factors such as climate change and ultraviolet radiation, can extend the service life of the solar cell backsheet, and improve economic benefits. Detailed implementation manners

[0025] To solve the above problems, the present invention provides a preparation method of a nano-composite reinforced weather-resistant solar cell backsheet polyester film in the first aspect of the present invention, including the following steps:

[0026] Step 1: Prepare modified polyethylene terephthalate; after thoroughly mixing polyethylene terephthalate and a modifier evenly, perform melt blending in a twin-screw extruder; the screw speed is (15-30) r / min, the melting temperature is 250-300 °C, and the mixing time is 3-5 h; the weight part of the modifier is 0.5-1.2.

[0027] Step 2: Add a weather-resistant composition to the evenly mixed molten modified polyethylene terephthalate, continue to perform melt mixing and vacuum pumping in a twin-screw extruder, the screw speed is (15-30) r / min, the melting temperature is 250-300 °C, the mixing time is 3-5 h, and the vacuum degree is 90-140 mmHg; pump vacuum until the mixture of the weather-resistant composition and the modified polyethylene terephthalate is evenly mixed and there are no bubbles in the stirring; the weight part of the weather-resistant composition is 15-28.

[0028] Step 3: Prepare a polyester film; dry the mixture of the weather-resistant composition and the modified polyethylene terephthalate obtained in Step 2 and put it into an extruder, and the extrusion temperature is 250-300 °C; the extruded thick sheet is transversely stretched 3-5 times at 80-100 °C, the extruded thick sheet is longitudinally stretched 3-5 times at 80-100 °C, and after transverse and longitudinal stretching, it is heat-set at 180-220 °C, wound and slit to obtain a finished product.

[0029] The present invention is further configured such that the modifier is a composite carbon material.

[0030] The present invention is further configured such that the composite carbon material is composed of carbon nanotubes and graphene in a mass ratio of (1 - 3)∶(2 - 4).

[0031] The present invention is further configured such that the weather resistance composition includes a hydrolysis resistant agent, a water blocking agent, an antioxidant, and an ultraviolet absorber.

[0032] The present invention is further configured such that the hydrolysis resistant agent includes one of carbodiimide polymers and multifunctional epoxy - type hydrolysis resistant agents;

[0033] The water blocking agent includes one of organic bentonite and ethylene - vinyl acetate copolymer;

[0034] The antioxidant includes one of hindered phenol antioxidants and phosphite antioxidants;

[0035] The ultraviolet absorber includes one of benzotriazole ultraviolet absorbers and triazine ultraviolet absorbers.

[0036] The present invention is further configured such that the hydrolysis resistant agent is a carbodiimide polymer;

[0037] The water blocking agent is organic bentonite;

[0038] The antioxidant is hindered phenol antioxidant 1010;

[0039] The ultraviolet absorber is benzotriazole ultraviolet absorber UV - 326.

[0040] The present invention is further configured such that the mass ratio of the hydrolysis resistant agent, the water blocking agent, the antioxidant, and the ultraviolet absorber is (6 - 9)∶(3 - 6)∶(3 - 5)∶(2 - 4).

[0041] The present invention is further configured such that the mass ratio of the hydrolysis resistant agent, the water blocking agent, the antioxidant, and the ultraviolet absorber is 7∶4∶4∶3.

[0042] An application of the reinforced polyester film for a solar cell backsheet, wherein the reinforced polyester film prepared according to the described method is applied to a solar cell backsheet.

[0043] The polyester film prepared by the present invention has good tensile strength, weather resistance, and water resistance, has a good tolerance effect on environmental factors such as climate change and ultraviolet radiation, can extend the service life of the solar cell backsheet, and improve economic benefits.

[0044] The composite carbon material is composed of carbon nanotubes and graphene in a certain proportion. Carbon nanotubes have excellent mechanical properties and electrical conductivity, and graphene has good barrier properties and thermal conductivity. The combination of the two can exert a synergistic effect to further enhance the properties of polyethylene terephthalate, such as enhancing the strength, electrical conductivity, and barrier properties of the film, etc.

[0045] Parts by weight of the modifier: The parts by weight of the modifier are adjusted from 0.3 - 0.8 to 0.5 - 1.2, and the amount of the modifier is appropriately increased to better exert its modification effect.

[0046] Weather-resistant composition

[0047] Increased ultraviolet absorber: An ultraviolet absorber, such as benzotriazole ultraviolet absorber UV-326, is added to the weather-resistant composition. Ultraviolet light is one of the main factors causing the aging of polyester films. The ultraviolet absorber can absorb ultraviolet light and convert it into heat energy for release, thereby reducing the damage of ultraviolet light to the film and improving the weather resistance of the film.

[0048] Hydrolysis-resistant agent, water-blocking agent and anti-aging agent: The hydrolysis-resistant agent is a carbodiimide polymer, which has better hydrolysis stability; the water-blocking agent is organic bentonite, which has good water absorption and swelling properties and can effectively prevent water penetration; the anti-aging agent is a hindered phenol anti-aging agent 1010, which is a highly efficient antioxidant and can effectively inhibit the oxidative aging of the film.

[0049] Parts by weight of the weather-resistant composition and mass ratios of each component: The parts by weight of the weather-resistant composition are 15 - 28 to enhance its improvement effect on the film properties. At the same time, the mass ratios of the hydrolysis-resistant agent, water-blocking agent, anti-aging agent and ultraviolet absorber are re-determined to achieve better performance balance.

[0050] As described above, it is only a preferred embodiment of the present invention, and it is not a limitation of the invention in other forms. Any person skilled in the art may use the disclosed technical content to make changes or equivalent changes to equivalent embodiments, but as long as it does not depart from the technical solution content of the present invention, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A preparation method of a nano-composite reinforced weather-resistant polyester film for a solar cell backplane, characterized in that: It includes the following steps: Step 1: Prepare modified polyethylene terephthalate; after thoroughly mixing polyethylene terephthalate and a modifier evenly, perform melt blending in a twin-screw extruder; the screw speed is (15 - 30) r / min, the melting temperature is 250 - 300 °C, and the mixing time is 3 - 5 h; the weight part of the modifier is 0.5 - 1.

2. Step 2: Add a weather-resistant composition to the evenly mixed molten modified polyethylene terephthalate, continue to perform melt mixing and vacuum pumping in a twin-screw extruder, the screw speed is (15 - 30) r / min, the melting temperature is 250 - 300 °C, the mixing time is 3 - 5 h, and the vacuum degree is 90 - 140 mmHg; pump vacuum until the mixture of the weather-resistant composition and the modified polyethylene terephthalate is evenly mixed and there are no bubbles in stirring; the weight part of the weather-resistant composition is 15 - 28. Step 3: Prepare a polyester film; dry the mixture of the weather-resistant composition and the modified polyethylene terephthalate obtained in Step 2 and put it into an extruder, and the extrusion temperature is 250 - 300 °C; the extruded thick sheet is transversely stretched 3 - 5 times at 80 - 100 °C, the extruded thick sheet is longitudinally stretched 3 - 5 times at 80 - 100 °C, and after transverse and longitudinal stretching, it is heat-set at 180 - 220 °C, wound and slit to obtain the finished product.

2. The preparation method of a nano-composite reinforced weather-resistant solar cell backplane polyester film according to claim 1, characterized in that: The modifier is a composite carbon material.

3. The preparation method of a nano-composite reinforced weather-resistant solar cell backsheet polyester film according to claim 2, characterized in that: The composite carbon material is composed of carbon nanotubes and graphene in a mass ratio of (1 - 3)∶(2 - 4).

4. The preparation method of a nano-composite reinforced weather-resistant polyester film for a solar cell backplane according to claim 1, wherein: The weather-resistant composition includes a hydrolysis-resistant agent, a water-blocking agent, an antioxidant, and an ultraviolet absorber.

5. According to the preparation method of a nano-composite reinforced weather-resistant polyester film for a solar cell backplane described in claim 4, characterized in that: The hydrolysis-resistant agent includes one of carbodiimide polymers and multi-functional epoxy-based hydrolysis-resistant agents; The water-blocking agent includes one of organic bentonite and ethylene-vinyl acetate copolymer; The antioxidant includes one of hindered phenol antioxidants and phosphite antioxidants; The ultraviolet absorber includes one of benzotriazole ultraviolet absorbers and triazine ultraviolet absorbers.

6. According to the preparation method of a nano-composite reinforced weather-resistant polyester film for a solar cell backplane described in claim 5, characterized in that: The hydrolysis-resistant agent is a carbodiimide polymer; The water-blocking agent is organic bentonite; The antioxidant is hindered phenol antioxidant 1010; The ultraviolet absorber is benzotriazole ultraviolet absorber UV-326.

7. The preparation method of a nano-composite reinforced weather-resistant polyester film for a solar cell backplane according to claim 6, characterized in that: The mass ratio of the hydrolysis-resistant agent, the water-blocking agent, the antioxidant, and the ultraviolet absorber is (6 - 9)∶(3 - 6)∶(3 - 5)∶(2 - 4).

8. The preparation method of a nano-composite reinforced weather-resistant polyester film for a solar cell backplane according to claim 7, characterized in that: The mass ratio of the hydrolysis-resistant agent, the water-blocking agent, the antioxidant, and the ultraviolet absorber is 7∶4∶4∶3.

9. Application of a nano-composite reinforced weather-resistant polyester film for a solar cell backsheet, characterized in that: The reinforced polyester film prepared by the method according to any one of claims 1 - 8 is applied to a solar cell backplane.