Urethane Adhesive Composition Mixing Ratio Tolerance
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Solution Overview
Problem
Two-liquid urethane adhesive compositions face a challenge in maintaining high adhesive strength and elastic modulus when the mixing ratio of the main agent and curing agent deviates from the designed range, leading to significant reductions in physical properties of the cured product.
Innovation Solution
Incorporating a specific high molecular weight polyol and two types of low molecular weight polyols in the curing agent, with the main agent having a high isocyanate group content, to stabilize the physical properties even when the mixing ratio falls outside the designed range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the mixing ratio of main agent and curing agent is precisely controlled to achieve high adhesive strength and elastic modulus, then the physical properties of the cured product are improved, but the ease of operation and tolerance to mixing ratio variations deteriorate
Solution Approach 1:
The invention changes the chemical composition parameters of the curing agent by introducing a specific combination of polyols (high molecular weight polyol with 2-3 hydroxyl groups and number average molecular weight of 1800 or more, low molecular weight polyol A with two hydroxyl groups and number average molecular weight of 200 or less, and low molecular weight polyol B with three hydroxyl groups including secondary hydroxyl groups and number average molecular weight of 1200 or less). This specific parameter combination enables the curing agent to maintain effective curing even when mixing ratio variations occur, thus resolving the contradiction between achieving high adhesive strength and maintaining operational tolerance.
2Strength
If the density of urethane bonds is increased to achieve high elastic modulus, then the mechanical properties are improved, but the sensitivity to mixing ratio deviations increases
Solution Approach 1:
The invention uses a composite curing agent system combining three specific types of polyols with different molecular weights and hydroxyl group configurations. This composite approach creates a balanced reaction system where the high molecular weight polyol provides backbone structure and the low molecular weight polyols fill in reactive groups, ensuring complete curing and high elastic modulus while maintaining reliability against mixing ratio deviations through the synergistic effect of the composite formulation.
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 urethane adhesive composition effectively suppresses the reduction in physical properties of the cured product, maintaining high adhesive strength and elastic modulus, and achieving superior adhesion development performance.
Implementation Method 1
a two-liquid type urethane adhesive composition comprising a main agent and a curing agent... the main agent contains a polyisocyanate component... the curing agent contains a compound having a plurality of active hydrogen-containing groups per molecule
Data Source
AI summary
A two-liquid type urethane adhesive composition includes a main agent and a curing agent. The main agent includes a poly isocyanate component, and the isocyanate group content in the main agent is 5 mass % or more of the total amount. The curing agent contains a compound having a plurality of active hydrogen-containing groups per molecule, and the compound having a plurality of active hydrogen-containing groups per molecule includes a high molecular weight polyol having two or three hydroxyl groups per molecule and a number average molecular weight of 1800 or greater, a low molecular weight polyol A having two hydroxyl groups per molecule and a number average molecular weight of 200 or less, and a low molecular weight polyol B having three hydroxyl groups per molecule, with at least one of the three hydroxyl groups being secondary hydroxyl groups, and a number average molecular weight of 1200 or less.