Fluorinated Polymer Coating for Solar Backsheet Adhesion
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Solution Overview
Problem
Current coating materials for solar cell module backsheets face challenges in achieving satisfactory adhesiveness to sealants like EVA and resistance to blocking phenomena, which can lead to coating film adhesion issues during winding or stacking.
Innovation Solution
A coating material comprising a curable functional group-containing fluorinated polymer and a polyisocyanate compound, specifically derived from bis(isocyanatomethyl)cyclohexane, is used to form a coating film that exhibits excellent adhesiveness to sealants and resistance to blocking, thereby improving the performance of solar cell module backsheets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a PVdF-based coating material is used for the backsheet, then weathering resistance and waterproofness are improved, but adhesiveness to the EVA sealant deteriorates
Solution Approach 1:
The coating material employs functional group-free fluorinated polymer as the base resin to provide uniform weathering resistance and waterproofness across the coating film, while locally introducing tetraalkoxysilane compounds at the interface with the EVA sealant to enhance adhesion. This local modification of chemical composition at the bonding interface resolves the contradiction between overall coating performance and interfacial adhesion.
Solution Approach 2:
Tetraalkoxysilane compounds serve as intermediary substances between the fluorinated polymer coating and the EVA sealant. These compounds form a chemical bridge that enhances adhesion without compromising the weathering resistance provided by the fluorinated polymer matrix. The silane compounds react with both the coating and the sealant, creating a strong interfacial bond.
2Weight of moving object
If the backsheet thickness is reduced to decrease weight, then productivity and cost are improved, but mechanical strength and durability deteriorate
Solution Approach 1:
The invention creates a composite coating system combining functional group-free fluorinated polymer with tetraalkoxysilane compounds. This composite structure provides enhanced mechanical properties and adhesion strength that allow the use of thinner backsheets while maintaining required durability and mechanical performance.
Solution Approach 2:
The invention changes the chemical composition parameters of the coating material by introducing tetraalkoxysilane compounds with specific molecular structures and reactive groups. This parameter modification enhances the coating's mechanical strength and bonding capability, enabling thickness reduction without sacrificing performance.
3Weight of moving object
If a curable functional group-containing fluorinated polymer coating material is used to reduce thickness, then weight and thickness are reduced, but adhesiveness to the water-impermeable sheet may deteriorate without additional additives
Solution Approach 1:
Tetraalkoxysilane compounds function as intermediary substances that enhance adhesion between the fluorinated polymer coating and the water-impermeable sheet substrate. These compounds create chemical bonds with both the coating matrix and the substrate surface, ensuring strong bonding even in thin-coating configurations.
Solution Approach 2:
The coating material concentrates adhesion-enhancing tetraalkoxysilane compounds at the interface region with the water-impermeable sheet, while maintaining the functional group-free fluorinated polymer as the bulk matrix. This local quality differentiation ensures strong substrate bonding without compromising the overall coating performance.
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 coating film demonstrates enhanced adhesiveness to EVA sealants and improved blocking resistance, ensuring reliable performance and preventing coating film adhesion issues during the winding process, thus enhancing the durability and efficiency of solar cell module backsheets.
Implementation Method 1
a coating material that comprises a curable functional group-containing fluorinated polymer and a polyisocyanate compound
Data Source
Figure 1~3
AI summary
An object of the present invention is to provide a coating material that can form a coating film that has an excellent adherence for sealants in solar cell modules as well as an excellent resistance to blocking. Further objects are to provide this coating film, a solar cell module backsheet that has this coating film, and a solar cell module that has this coating film. The present invention relates to a coating material that contains a curable functional group-containing fluorinated polymer and a polyisocyanate compound derived from at least one isocyanate selected from the group consisting of xylylene diisocyanate and bis(isocyanatomethyl)cyclohexane.