Solventless Laminate Adhesive for PV Backsheet Aging Resistance
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Solution Overview
Problem
Existing adhesive compositions for photovoltaic devices fail to provide sufficient bond strength, aging resistance, and weathering resistance, leading to premature failure when exposed to harsh outdoor conditions.
Innovation Solution
A solventless adhesive composition comprising a prepolymer derived from cyclohexyl(ene) group-containing monomeric isocyanate and polycarbonate, polyester, and polyether polyols, with a specific NCO functionality, is used to create a laminate material with improved adhesion and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional adhesive compositions are used for photovoltaic device backsheet lamination, then the lamination process can be completed, but the bond strength and aging resistance are insufficient leading to premature failure under outdoor conditions
Solution Approach 1:
The patent changes the chemical composition parameters of the adhesive by using a two-component system with specific isocyanate and polyol components in controlled ratios. The adhesive contains 10-40 wt% of component (a) and 60-90 wt% of component (b), creating optimal crosslinking density and molecular structure that enhances bond strength and weathering resistance without premature failure
Solution Approach 2:
The patent creates a composite adhesive system by combining two distinct chemical components: (a) a polyol component with specific hydroxyl functionality and (b) an isocyanate component with specific NCO content. This composite formulation produces synergistic effects where the interaction between components creates superior aging resistance and bond strength compared to single-component adhesives
2Strength
If adhesive compositions with high bonding capability are used, then bond strength is improved, but yellowing resistance and long-term aging resistance deteriorate
Solution Approach 1:
The patent carefully controls the NCO content (10-40 wt%) and hydroxyl functionality (0.5-2.0 mmol/g) parameters to achieve optimal balance. The isocyanate component uses cycloaliphatic structures instead of aromatic ones, which fundamentally changes the chemical stability and eliminates yellowing while maintaining strong crosslinking and bond strength
Solution Approach 2:
The patent replaces traditional aromatic isocyanates that cause yellowing with cycloaliphatic isocyanates that provide UV stability and yellowing resistance. This substitution sacrifices some initial reactivity but gains long-term durability and color stability under outdoor exposure
3Ease of operation
If solvent-based adhesive compositions are used, then application and processing are easier, but the adhesive lacks sufficient aging and weathering resistance for outdoor photovoltaic applications
Solution Approach 1:
The patent removes solvents from the adhesive composition entirely, creating a 100% solid-content two-component system. This extraction of harmful solvents eliminates their negative impact on aging resistance while the components are kept separately in containers and mixed only before application, maintaining ease of use through simple mixing procedures
Solution Approach 2:
The patent performs preliminary preparation by pre-synthesizing the polyol component with specific molecular weight and hydroxyl functionality, and pre-preparing the isocyanate component with controlled NCO content. These pre-prepared components are stored separately and only mixed immediately before application, ensuring optimal performance while maintaining operational simplicity
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 laminate material exhibits superior bond strength, aging resistance, and yellowing resistance, ensuring long-term performance under outdoor conditions.
Implementation Method 1
a two-component polyol component (b) and an isocyanate component (a)... wherein the prepolymer comprises more than one free isocyanate groups
Implementation Method 2
exhibits superior performance properties such as bond strength, aging resistance, yellowing resistance, delamination resistance
Implementation Method 3
high resistance to the long term aging and weathering (i.e. the influence of sunlight, wind, rain, debris)
Data Source
AI summary
Disclosed is a solventless adhesive composition comprising (A) an isocyanate component obtained by the reaction of reactants comprising at least one monomeric cycloaliphatic isocyanate compound and at least one first polyol; and (B) a polyol component comprising particularly selected polyols. The solventless adhesive composition can be used for the production of laminate materials, e.g. laminate backsheet of a photovoltaic device, which well meets the requirements of various compliance regulations and has superior performance properties such as bond strength, aging resistance, yellowing resistance, delamination resistance, and the like. A method for producing said laminate material and the resultant laminate material are also disclosed.