Dual Component Adhesive Low-Temperature Curing
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Solution Overview
Problem
Existing two-component adhesives based on polyisocyanurate require high temperatures for curing, limiting their application and handling, and often result in brittle products with high hardness and low impact strength.
Innovation Solution
A two-component adhesive system comprising a first component with monomeric polyisocyanate and isocyanate-terminated prepolymer, and a second component with diamine and trimerization catalyst, which forms a highly exothermic reaction to create a crosslinked prepolymer with enhanced trimerization, resulting in higher tensile and heat resistance, as well as impact strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high temperatures are used for curing polyisocyanurate-based adhesives, then curing is achieved, but application complexity and equipment requirements increase
Solution Approach 1:
The invention changes the curing temperature parameter from high temperature (conventional polyisocyanurate) to room temperature or moderate temperature (invention adhesive). This is achieved by using a monomeric polyisocyanate with specific reactivity and a polyol component that enables low-temperature curing, eliminating the need for heating equipment and temporary storage in heating ovens.
Solution Approach 2:
The invention replaces expensive and complex high-temperature curing systems with a simpler, single-use adhesive system that cures at ambient temperatures. The adhesive components are designed to be mixed and applied directly without requiring costly heating equipment or specialized curing infrastructure.
2Strength
If polyisocyanurate-based adhesives are used, then high strength is achieved, but brittleness increases
Solution Approach 1:
The invention creates a composite adhesive system combining monomeric polyisocyanate, polyol, and catalyst components that work synergistically. The polyol component provides flexibility and toughness while the polyisocyanate provides strength, creating a balanced adhesive that achieves both high tensile strength and impact resistance without the extreme brittleness of conventional polyisocyanurates.
Solution Approach 2:
The invention changes the chemical composition parameters by selecting specific polyol types (polyether polyols, polyester polyols) and their molecular weight ranges, as well as the polyisocyanate to polyol ratio. These parameter adjustments optimize the balance between strength and flexibility, reducing brittleness while maintaining high adhesive strength.
3Ease of operation
If conventional polyurethane adhesives are used, then ease of handling is achieved, but impact strength is limited
Solution Approach 1:
The invention enhances conventional polyurethane adhesive formulation by incorporating a catalyst component (organic peroxide or azo compound) that accelerates curing and improves crosslinking density. This composite approach maintains the ease of handling and room-temperature application of polyurethane adhesives while significantly boosting impact strength and overall mechanical performance.
Solution Approach 2:
The catalyst component acts as an intermediary that facilitates the reaction between polyisocyanate and polyol, enabling faster curing and improved network formation. This intermediary substance allows the adhesive to achieve high impact strength without compromising the ease of application and handling during the working period.
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 higher tensile strength, heat resistance, and impact strength compared to traditional polyurethane and polyurea adhesives, with improved handling and application flexibility, and reduced brittleness.
Implementation Method 1
The reaction between the amine groups and the isocyanates is approximately an order of magnitude faster than that between the hydroxyl groups of the polyol components and the isocyanates of the polyurethane adhesives.
Implementation Method 2
The formation of trimeric heterocyclic isocyanurates to polyisocanurates (PIR) when using trimerization catalysts is known.
Implementation Method 3
Accordingly, in contrast to urethane formation, urea formation is accompanied by a release of thermal energy.
Data Source
AI summary
The invention relates to a two-component adhesive comprising a component A and a component B. Component A contains a monomeric polyisocyanate, in particular a monomeric diisocyanate, and an isocyanate-terminated prepolymer and/or a prepolymer mixture with an isocyanate functionality ≥ 1.7, preferably in the range of 1.7 < fNCO < 3, particularly preferably in the range of 2 < fNCO < 3. Component B contains a di- and/or polyamine, preferably a polyether diamine and/or a polyether polyamine, and at least one trimerization catalyst. The stoichiometric ratio of isocyanate groups in the first component (A) to isocyanate-reactive hydrogen atoms contained in the composition, in particular reactive hydrogen atoms of the di- and/or polyamine, in the second component (B) is 7.5 to 25, preferably 10 to 20, particularly preferably 15.Such a two-component adhesive is easier to handle, has a wider range of applications, and is strong after curing, yet not very brittle.