Polyisocyanate Adhesive Trimerization for High Crosslink Density
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Solution Overview
Problem
Standard polyurethane adhesives have low crosslink density, leading to inadequate performance in severe climatic conditions and slow cure rates, which limits their use in applications like car body adhesives and flexible food packaging, and they often fail due to adhesion or cohesion failures under stress.
Innovation Solution
A polyisocyanate-based adhesive is developed by reacting an organic polyisocyanate with a compound containing isocyanate-reactive hydrogen atoms in the presence of a trimerization catalyst, resulting in a polyisocyanurate-based adhesive with high crosslink density and fast cure rates, enhancing resistance to stress and reducing aromatic amine migration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If standard polyurethane adhesives are used, then processing is simple and economical, but crosslink density is too low for severe climatic conditions
Solution Approach 1:
The patent changes the chemical composition parameters of the adhesive by incorporating polyisocyanurate structures and specific polyol components (polyester polyol and/or polyether polyol) to achieve high crosslink density while maintaining processability. The adhesive contains 5-50 parts by weight polyester polyol and/or polyether polyol per 100 parts by weight polyisocyanate, creating optimal crosslinking for severe condition resistance.
Solution Approach 2:
The patent creates a composite adhesive system combining polyisocyanate, polyester polyol, polyether polyol, and polyisocyanurate structures. This composite formulation integrates multiple functional components to simultaneously achieve simple processing and high reliability in heat and salt water resistance.
2Ease of manufacture
If standard polyurethane adhesives are used, then formulation is simple, but cure rate is very slow requiring prolonged storage
Solution Approach 1:
The patent changes the chemical reactivity parameters by incorporating polyisocyanurate structures which accelerate the cure rate. The specific composition (5-50 parts polyester polyol and/or polyether polyol per 100 parts polyisocyanate) optimizes both formulation simplicity and cure speed, reducing storage time to meet aromatic amine limits.
3Strength
If adhesive bond strength is increased to resist higher stresses, then cohesion and adhesion failure are avoided, but crosslink density must be increased
Solution Approach 1:
The patent optimizes the crosslink density parameter through specific compositional ratios: 5-50 parts polyester polyol and/or polyether polyol per 100 parts polyisocyanate, and 40-95 parts polyisocyanurate per 100 parts total adhesive. This achieves high bond strength while controlling the complexity of the crosslinked network.
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 polyisocyanurate-based adhesive provides improved strength, resistance to unfavorable media, and faster aromatic amine reduction, addressing the limitations of standard polyurethane adhesives by offering better performance in severe conditions and compliance with legal aromatic amine limits.
Implementation Method 1
the polyisocyanate-based adhesive according to the present invention can become a polyisocyanurate-based adhesive
Implementation Method 2
reacting an organic polyisocyanate with a compound containing isocyanate-reactive hydrogen atoms in the presence of a trimerisation catalyst
Data Source
AI summary
Adhesive prepared by reacting an organic polyisocyanate with a compound containing isocyanate-reactive hydrogen atoms in the presence of a trimerization catalyst. The softblock content of the adhesive is between 20 and 70 wt %.