Reactive Polyurethane Adhesive Composition for Fast Cure and Thermal Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional moisture curing polyurethane adhesives exhibit slow curing rates and thermal instability, particularly when used in industrial applications involving elevated temperatures, leading to prolonged curing times and uneven bonding.
Innovation Solution
A one-part reactive adhesive composition comprising isocyanate-functional polyurethane prepolymers, a sulfide compound with hydrolysable silane groups as a complexing agent, and a metal catalyst that forms thiol complexes to accelerate curing while maintaining thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If metal catalyst is used to accelerate curing reactions, then curing speed is improved, but thermal stability deteriorates
Solution Approach 1:
The patent introduces a complexing agent as an intermediary substance that forms a complex with the metal catalyst. This complex acts as a mediator that moderates the catalyst's activity, reducing its harmful impact on thermal stability while preserving its ability to accelerate curing reactions. The complexing agent bridges between the catalyst and the adhesive system, enabling controlled acceleration without compromising thermal performance.
Solution Approach 2:
The patent changes the chemical state of the metal catalyst by forming a complex with a complexing agent. This parameter change transforms the catalyst from a highly active but thermally unstable form to a moderated form with optimized properties. The complexation alters the catalyst's electronic and steric environment, tuning its activity and thermal stability to achieve the desired balance between curing speed and thermal resistance.
2Stability of the object's composition
If tertiary amine catalyst is used instead of metal catalyst, then thermal stability is improved, but adhesion to metal substrates deteriorates
Solution Approach 1:
The complexing agent serves as an intermediary that modifies the metal catalyst's interaction with the adhesive system and metal substrates. By forming a complex, the catalyst's surface activity is tuned to maintain strong metal substrate adhesion while reducing thermal degradation. The complex acts as a bridge between the catalyst and substrate, preserving bonding strength without the thermal instability of pure metal catalysts.
3Ease of operation
If conventional moisture curing adhesives are used, then ease of operation is improved, but curing time increases
Solution Approach 1:
The patent changes the kinetic parameters of the curing reaction by introducing a metal catalyst complexed with a complexing agent. This parameter change accelerates the moisture curing reaction rate significantly compared to conventional uncatalyzed or amine-catalyzed systems. The complexed catalyst optimizes the reaction kinetics, reducing curing time while maintaining the simple one-part application method that ensures ease of operation.
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 composition achieves fast curing with excellent adhesion to metal substrates, suitable for industrial applications, overcoming the limitations of conventional adhesives in terms of speed and thermal stability.
Implementation Method 1
at least one metal catalyst C that can catalyze reactions between isocyanate groups and isocyanate reactive groups
Implementation Method 2
the silane groups of the polyolefin polymers, such as methoxysilane groups, react with water to form silanols
Implementation Method 3
which subsequently undergo reaction with other silanol groups to form covalent bonds between individual polymer molecules as part of a condensation reaction
Implementation Method 4
When contacted with water, the free isocyanate groups of the polyurethane prepolymers form carbamic acid
Data Source
AI summary
The invention relates to an adhesive composition comprising: a) A polyurethane polymer PU having isocyanate groups, b) At least one complexing agent CA, and c) At least one metal catalyst C that can catalyze reactions between isocyanate groups and isocyanate reactive groups and that can build thiol complexes, wherein the complexing agent CA is a sulfide compound having at least one hydrolysable silane group.