Polyurethane Adhesive Cure Acceleration for Fast Drive-Away Bonding
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Solution Overview
Problem
Existing one-part and two-part adhesive compositions for bonding glass in vehicles and buildings face challenges in achieving rapid cure times, consistent adhesive beads, and sufficient workability under varying ambient conditions, particularly when replacing vehicle windows.
Innovation Solution
A moisture curable adhesive system comprising an isocyanate terminated prepolymer and a cure accelerator with specific components, including triethanolamine and a polyol without primary, secondary, or tertiary amino groups, allows for rapid curing while maintaining adequate working time and uniformity, using a 2K packaging solution with a static mixer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If two-part adhesive compositions are used to achieve fast cure times, then drive away time is reduced to 30 minutes, but the system requires complex delivery systems and sufficient mixing to realize a uniform product
Solution Approach 1:
The adhesive system is divided into two separate components (isocyanate terminated prepolymer and cure accelerator) that are mixed at the point of application through a static mixer, allowing fast cure times while maintaining simpler delivery systems compared to traditional two-part adhesives
Solution Approach 2:
A static mixer is used as an intermediary device that automatically combines the two adhesive components in the correct ratio at the point of application, eliminating the need for complex delivery systems and manual mixing while ensuring uniform product formation
2Loss of time
If two-part adhesive compositions are used to achieve fast cure times, then drive away time is reduced to 30 minutes, but the system requires sufficient mixing when dispensing to realize a uniform product
Solution Approach 1:
The static mixer enables the adhesive system to self-mix the two components automatically during dispensing, eliminating the need for external mixing operations or manual intervention while ensuring uniform product formation and maintaining fast drive away times
3Loss of time
If two-part adhesive compositions react quickly to allow fast drive away times, then 30 minute drive away is achieved, but the system may form skins resulting in insufficient working time under certain conditions
Solution Approach 1:
The adhesive system dynamically adjusts its curing behavior through the interaction of isocyanate terminated prepolymer and cure accelerator components, providing sufficient working time for window positioning while maintaining fast drive away times under varying ambient conditions
Solution Approach 2:
The curing parameters of the adhesive system are optimized by selecting specific isocyanate terminated prepolymer and cure accelerator components that provide balanced working time and fast cure characteristics, preventing skin formation while achieving 30 minute drive away times
4Loss of time
If one-part moisture curing adhesives are used to facilitate fast drive away times, then short initial cure is achieved, but the adhesives require much longer times to fully cure and inconsistently cured depending on ambient conditions
Solution Approach 1:
The cure accelerator acts as an intermediary that mediates the curing reaction between the isocyanate terminated prepolymer and moisture, providing consistent and reliable cure results while maintaining fast initial cure times under varying ambient conditions
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 system achieves sufficient strength for immediate vehicle use within 30 minutes, provides consistent adhesive beads, and maintains workability under varying conditions, ensuring fast drive-away times and reliable bonding.
Implementation Method 1
One-part moisture curing adhesives have been used to bond windows into buildings and vehicles
Implementation Method 2
a cure accelerator comprised of i) an isocyanate reactive compound being triethanolamine
Data Source
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Figure 2
AI summary
Disclosed is an adhesive system and method of use thereof wherein the adhesive composition comprises a moisture curable adhesive comprised of an isocyanate terminated prepolymer and a cure accelerator having two curatives components having different cure kinetics. The cure accelerator is comprised of an isocyanate reactive compound comprising a primary, secondary or tertiary amino group, or a primary thiol group having faster curing kinetics resulting an increase in bead stability within the first minutes and a polyol selected from a diol and/or triol with slower curing kinetics allowing for sufficient open time and yet a fast strength build up. The preferred method of application of the adhesive system is via a 1K application gun.