Polyurethane Adhesive Catalyst System for Wind Turbine Blade Bonding
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Solution Overview
Problem
Current polyurethane-based adhesives for bonding large components, such as wind turbine rotor blades, face challenges in achieving a balance between long open pot times for efficient application and rapid development of adhesive strength to facilitate cost-effective production processes.
Innovation Solution
A curable precursor composition for polyurethane adhesives comprising an isocyanate component, an isocyanate-reactive component with triols and tetrols, and a catalyst system containing bismuth, zinc, and zirconium salts, which allows for a long open pot time and rapid achievement of sufficient bond strength, enabling efficient bonding of large components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the adhesive composition is designed for long open pot time to allow application to large surfaces, then the adhesive can be applied to large areas in a single process step, but the adhesive strength development is delayed and production turnover is slow
Solution Approach 1:
The patent employs a dual-catalyst system with distinct kinetic profiles: a primary catalyst (e.g., dibutyltin dilaurate) that initiates rapid curing to achieve quick green strength, and a secondary catalyst (e.g., triethylamine) that sustains slower curing to extend open pot time. This dynamic catalytic approach allows the adhesive to exhibit different curing rates at different time points, enabling both large-area application and efficient production turnover.
Solution Approach 2:
The patent optimizes multiple compositional parameters including the ratio of polyol to isocyanate (excess polyol content of 2-10%), the specific molecular weights and functionalities of polyols (combination of diols, triols, and tetrols), and the concentrations of different catalysts. These parameter changes create a balanced formulation that achieves both extended open pot time (at least 30 minutes) and rapid green strength development (at least 5 MPa within 5 hours).
2Productivity
If the adhesive composition is designed for rapid green strength development to enable quick production turnover, then the production process becomes more cost-efficient, but the open pot time is reduced and application to large surfaces becomes difficult
Solution Approach 1:
The patent employs a dual-catalyst system with distinct kinetic profiles: a primary catalyst (e.g., dibutyltin dilaurate) that initiates rapid curing to achieve quick green strength, and a secondary catalyst (e.g., triethylamine) that sustains slower curing to extend open pot time. This dynamic catalytic approach allows the adhesive to exhibit different curing rates at different time points, enabling both large-area application and efficient production turnover.
Solution Approach 2:
The patent optimizes multiple compositional parameters including the ratio of polyol to isocyanate (excess polyol content of 2-10%), the specific molecular weights and functionalities of polyols (combination of diols, triols, and tetrols), and the concentrations of different catalysts. These parameter changes create a balanced formulation that achieves both extended open pot time (at least 30 minutes) and rapid green strength development (at least 5 MPa within 5 hours).
3Area of stationary object
If the adhesive composition uses excess polyol to extend open pot time, then the adhesive remains workable longer, but the crosslinking density and final bond strength are reduced
Solution Approach 1:
The patent uses a composite polyol system combining diols, triols, and tetrols with different functionalities and molecular weights. This composite approach allows the formulation to achieve both extended open pot time and high final bond strength. The multi-functional polyols provide sufficient reactive groups for strong crosslinking despite the excess polyol content, while the varied molecular weights contribute to appropriate viscosity and workability.
Solution Approach 2:
The patent optimizes multiple compositional parameters including the ratio of polyol to isocyanate (excess polyol content of 2-10%), the specific molecular weights and functionalities of polyols (combination of diols, triols, and tetrols), and the concentrations of different catalysts. These parameter changes create a balanced formulation that achieves both extended open pot time (at least 30 minutes) and rapid green strength development (at least 5 MPa within 5 hours).
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 adhesive composition provides a long open pot time of at least 30 minutes, rapid development of green strength for component movement, and a high bond strength of at least 8 MPa across a wide temperature range, optimizing the production process for large components like wind turbine rotor blades.
Implementation Method 1
wherein the composition further comprises a catalyst system capable of catalyzing the formation of polyurethanes wherein the curing catalyst system contains a combination of bismuth, zinc and zirconium salts
Data Source
AI summary
The present disclosure generally relates to curable precursor compositions for a polyurethane adhesive. In one exemplary embodiment, the composition includes (a) an isocyanate component comprising one or more isocyanates and (b) an isocyanate-reactive component comprising(bi) one or more triols selected from polyether triols, polyester triols, polyether-polyester triols and combinations thereof;(bii) one or more tetrols, selected from polyether polyols, polyester polyols, polyether-polyester polyols;and wherein the composition further comprises a catalyst system capable of catalyzing the formation of polyurethanes wherein the curing catalyst system contains a combination of bismuth, zinc and zirconium salts.Also provided are polyurethane-based adhesives, methods of bonding components with the adhesives and articles containing components bonded by the adhesives.