Fluorine-Polyester Resin Coating for PV Backsheet Adhesion
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Solution Overview
Problem
Current backsheet materials for photovoltaic modules, particularly those using fluorine-based polymers like PVF, face challenges such as poor adhesive strength, high manufacturing costs due to energy-intensive drying processes, and thermal deformation issues, which affect the durability and weather resistance of solar cells.
Innovation Solution
A resin composition comprising a fluorine-based polymer, an acrylic polymer with thermosetting functional groups, and a heat-curing agent is developed, allowing for a multi-layered film with improved adhesive strength and durability, which can be processed at lower temperatures, reducing manufacturing costs and preventing thermal deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PVF resin is used to provide excellent weather resistance and durability, then the backsheet can protect solar cells in external environment, but the adhesive strength to PET substrate is poor and requires expensive adhesive and laminating processes
Solution Approach 1:
The patent combines the fluorine-based polymer (PVF) with a polyester resin in a single coating layer, merging the weather resistance function of PVF with the adhesive function of polyester resin. This eliminates the need for separate adhesive layers and laminating processes while maintaining both protective and bonding functions in one integrated coating system.
Solution Approach 2:
The invention uses a composite material system consisting of fluorine-based polymer and polyester resin in specific weight ratios (PVF: 1-50 wt%, polyester resin: 50-99 wt%). This composite approach allows the coating to simultaneously achieve the weather resistance properties of fluorine polymers and the adhesive properties of polyester resins, solving both requirements in a single material system.
2Quantity of substance
If high drying temperature of at least 200 °C is used to dry fluorine-based polymer resin suspension, then the resin can be properly dried, but a great amount of energy is consumed and thermal shock or thermal deformation occurs to the substrate
Solution Approach 1:
The patent changes the drying temperature parameter from the conventional high temperature (≥200°C) to a lower temperature range (60-150°C). This parameter change is enabled by the specific resin composition formulation that allows complete drying and curing at lower temperatures, thereby reducing energy consumption by more than 50% and preventing thermal shock to the substrate.
Solution Approach 2:
The invention applies different functional components in specific proportions within the coating layer: fluorine-based polymer (1-50 wt%) for weather resistance, polyester resin (50-99 wt%) for adhesion and low-temperature processing, and specific additives. This localized composition optimization enables low-temperature drying while maintaining complete resin curing and film formation quality.
3Quantity of substance
If high drying temperature of at least 200 °C is used, then the resin can be dried, but thermal deformation occurs to the substrate and quality of the product is degraded
Solution Approach 1:
The patent changes the drying temperature parameter from high temperature (≥200°C) to low temperature (60-150°C), which prevents thermal deformation of the PET substrate while achieving complete resin drying and curing. This parameter change maintains manufacturing precision by avoiding thermal shock and dimensional changes in the substrate.
Solution Approach 2:
The resin composition is pre-formulated with polyester resin as the main component (50-99 wt%) that has inherent low-temperature processing characteristics. This preliminary formulation ensures that when the coating is applied and dried, the resin system is already configured to cure properly at low temperatures, preventing substrate deformation before the drying process even begins.
4Productivity
If fluorine-based polymer film is manufactured by extruding or casting, then the film can be produced, but expensive facility is required and adhesive strength to substrate is poor
Solution Approach 1:
The patent merges the fluorine-based polymer with polyester resin in a single coating composition that is applied directly to the substrate. This combination eliminates the need for separate film extrusion or casting facilities and subsequent adhesive application equipment. The coating process integrates both the protective fluorine polymer and the adhesive polyester resin in one step, simplifying manufacturing infrastructure.
Solution Approach 2:
The invention extracts the adhesive function from the separate adhesive layer and laminating process and integrates it into the coating composition itself. By incorporating polyester resin (50-99 wt%) as the base resin that provides both adhesion to PET substrate and compatibility with fluorine polymer, the patent eliminates the need for separate adhesive materials and complex laminating equipment, requiring only standard coating facilities.
5Reliability
If PVF resin is used, then weather resistance is excellent, but various additives and fillers are limited and high process-temperature is required
Solution Approach 1:
The patent creates a composite material system where polyester resin (50-99 wt%) serves as the continuous phase that is highly compatible with various additives and fillers, while fluorine-based polymer (1-50 wt%) provides the weather resistance. The polyester resin matrix allows incorporation of diverse additives including UV stabilizers, pigments, and functional fillers that may not be compatible with pure fluorine polymer, thereby expanding additive versatility while maintaining weather resistance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The resin composition enhances the durability and weather resistance of photovoltaic modules by providing excellent adhesive strength and mechanical properties, while also lowering production costs through reduced energy consumption and preventing thermal damage during the manufacturing process.
Implementation Method 1
an acrylic polymer including at least one thermosetting functional group selected from the group consisting of a carboxyl group, an amide group, an amino group, an epoxy group, an isocyanate group, a cyano group, an acid anhydride group, a mercapto group, a silanol group, an alkoxysilane group, and an oxazoline group; and a heat-curing agent
Data Source
Figure 1
AI summary
A resin composition, a multi-layered film, a backsheet for photovoltaic modules, a method thereof, and a photovoltaic module are provided. The multi-layered film including a coating layer including a fluorine-based polymer has an excellent durability and weather resistance, and also exhibits high interfacial adhesive strength to a substrate since the multi-layered film is formed by coating a cured product of the resin composition including the fluorine-based polymer, an acrylic polymer including a thermosetting functional group, and a heat-curing agent on the substrate. In addition, drying can be performed at a low temperature during the manufacture of the multi-layered film so that the manufacturing costs can be decreased, productivity can be increased, and the deterioration of the product due to heat modification, heat shock, and the like, can be prevented. The multi-layered film can be effectively used as a backsheet for various photovoltaic modules.