Multilayer Solar Back Sheet Adhesion via Diene Tie Layer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional multilayer sheets for solar cells face challenges in achieving high interlayer adhesiveness, particularly when using fluorine-based and polyolefin-based resins, which are less adhesive to other resins, leading to insufficient bonding strength and thickness fluctuations during coextrusion processes.
Innovation Solution
A multilayer sheet is developed with a polyolefin-based resin layer, a polyvinylidene fluoride-based resin layer, and an adhesion resin layer made of a conjugated diene-based polymer, which improves interlayer adhesiveness and stability, using specific melt flow rates and thicknesses to ensure strong bonding and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fluorine-based resins and polyolefin-based resins are used in multilayer sheets, then weather resistance and heat resistance are improved, but interlayer adhesiveness deteriorates
Solution Approach 1:
The patent introduces a tie layer composed of a polymer with both polar and nonpolar groups as an intermediary between the fluorine-based resin layer and polyolefin-based resin layer. This tie layer acts as a mediator that can bond with both types of resins, resolving the adhesion problem caused by the chemical inertness of fluorine-based and polyolefin-based resins.
Solution Approach 2:
The patent creates a composite multilayer structure combining fluorine-based resin, polyolefin-based resin, and a tie layer polymer in specific configurations. This composite approach allows each material to contribute its strengths (weather resistance from fluorine-based resin, mechanical strength from polyolefin) while the tie layer ensures proper bonding between layers.
2Strength
If multiple films are laminated with adhesive, then interlayer bonding is achieved, but manufacturing complexity and production cost increase
Solution Approach 1:
The patent merges the adhesive function into the tie layer that is already part of the multilayer structure. Instead of adding a separate adhesive layer, the tie layer performs both structural connection and adhesion functions, simplifying the manufacturing process while maintaining bonding strength.
Solution Approach 2:
The tie layer is designed to inherently provide adhesion between layers through its chemical structure (polymers with both polar and nonpolar groups), eliminating the need for additional adhesives or complex lamination processes. The structure serves its own bonding function.
Data Source
Figure 1~2
AI summary
Provided are a multilayer sheet superior in weather resistance, heat resistance, and moisture proofness and also favorable in interlayer adhesiveness, and a back sheet for solar cells and a solar cell module prepared by using the same. The multilayer sheet 10 is prepared by laminating a polyolefin-based resin layer 1 having a melt flow rate, as determined by the method A specified in JIS K7210, of 0.5 to 25 g/10 minutes at 230°C under a load of 2.16 kg and a polyvinylidene fluoride-based resin layer 2 having a melt flow rate, as determined by the method A specified in JIS K7210, of 0.5 to 25 g/10 minutes at 230°C under a load of 2.16 kg, via an adhesion resin layer 3 of a conjugated diene-based polymer, a conjugated diene-based copolymer, or the hydride thereof having a melt flow rate, as determined by the method A specified in JIS K7210, of 0.1 to 50 g/10 minutes at 230°C under a load of 2.16 kg. Aback sheet prepared by using the multilayer sheet 10 is layered on a sealing material of a solar cell, to give a solar cell module.