Polyethylene Solar Seal Weak Crosslinking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Solar cell module-forming sealing materials based on polyethylene resins face challenges in achieving a balance between transparency, flexibility, and heat resistance, as reducing density to improve these properties leads to decreased heat resistance, and conventional crosslinking methods require high amounts of crosslinking agents, compromising flexibility and film forming ability.
Innovation Solution
A sealing material composition using low density polyethylene with a polymerization initiator at a lower concentration than conventional methods, allowing for weak crosslinking during molding, which maintains transparency and flexibility while enhancing heat resistance, and a multilayer structure with varying MFR and polymerization initiator content to optimize properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the density of polyethylene-based resin is reduced to improve transparency and flexibility, then transparency and flexibility are improved, but heat resistance decreases
Solution Approach 1:
The patent applies parameter changes by controlling the density of polyethylene-based resin within the specific range of 0.910-0.940 g/cm³ and adjusting the polymerization initiator content to 0.01-5 mass% to achieve weak crosslinking. This resolves the contradiction by finding an optimal parameter range that provides both transparency/flexibility (through low density) and heat resistance (through controlled crosslinking)
Solution Approach 2:
The patent creates a composite material system by combining polyethylene-based resin with a polymerization initiator to achieve weak crosslinking. This composite approach allows the material to exhibit both the transparency and flexibility of low-density polyethylene and the heat resistance provided by the crosslinked structure
2Temperature
If a large amount of crosslinking agent is added to improve heat resistance and flame retardancy, then heat resistance is improved, but flexibility and film forming ability decrease
Solution Approach 1:
The patent applies partial action by using a small amount of polymerization initiator (0.01-5 mass%) to achieve weak crosslinking rather than full crosslinking. This partial crosslinking provides sufficient heat resistance while maintaining the flexibility and film forming ability required for solar cell module sealing
Solution Approach 2:
The patent changes the parameter of crosslinking degree from conventional high crosslinking (30% gel fraction or more) to weak crosslinking (lower gel fraction) by controlling polymerization initiator content. This parameter change resolves the contradiction between heat resistance and flexibility
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 solution provides a solar cell module-forming sealing material with improved heat resistance and maintained transparency and flexibility, allowing for successful film formation and adherence, while reducing the need for high crosslinking agent amounts and minimizing post-molding crosslinking issues.
Implementation Method 1
a large amount of a crosslinking agent is added for this purpose... crosslinking has to be performed sufficiently... weakly crosslinked and increased in molecular weight
Implementation Method 2
the weak crosslinking reaction is allowed to proceed successfully by heating during molding
Data Source
AI summary
Disclosed are a sealing material for solar cell modules and a manufacturing method thereof capable of endowing good transparency and heat resistance to the sealing material for solar cell modules while using a polyethylene-based resin. The disclosed sealing material for solar cell modules uses a polyethylene-based resin with a density of 0.900 g/cm3 or less, and an MFR between 0.1 g/10 min and 1.0 g/10 min. The sealing material is obtained by melt molding a resin composition containing a polyethylene-based resin with density 0.890 g/cm3 or less, and a polymerization initiator contained at 0.02 mass % or more but less than 0.5 mass % of the composition, wherein the density difference of the resin composition before and after the melt molding is within 0.05 g/cm3, and the MFR difference of the resin composition before and after the melt molding is 1.0 g/10 min or greater.