Two-Part Urethane Adhesive Composition for Enhanced Bonding Strength
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Solution Overview
Problem
Conventional two-part urethane adhesive compositions often fail to achieve the required level of adhesion, particularly in applications such as automobiles, due to insufficient bonding strength.
Innovation Solution
A two-part urethane adhesive composition is developed, comprising a main agent with a polyisocyanate component and a curing agent containing water and an active hydrogen-containing compound with multiple active hydrogens, where specific ratios of isocyanate groups to active hydrogens and water are maintained within specific ranges to enhance adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional two-part urethane adhesive compositions are used, then the composition is simple and easy to manufacture, but the adhesion strength does not reach the currently required level
Solution Approach 1:
The patent applies parameter changes by precisely controlling the average active hydrogen concentration of the active hydrogen-containing compound (B) within 0.50 to 3.50 mol/kg and the average active hydrogen concentration of the active hydrogen-containing compound (B) and water within 2.00 to 8.00 mol/kg. These specific parameter ranges optimize the chemical reaction between isocyanate groups and active hydrogens, thereby achieving the required adhesion strength while managing composition complexity.
Solution Approach 2:
The patent employs composite materials by combining water and an active hydrogen-containing compound (B) in the curing agent, where the compound (B) contains a nitrogen-containing compound with specific structural features (Formula 4). This composite curing agent system creates synergistic effects that enhance adhesion strength beyond what single components could achieve, resolving the contradiction between strength improvement and composition complexity.
2Strength
If the active hydrogen concentration is increased to improve adhesion, then the bonding strength improves, but the composition becomes more complex and difficult to control
Solution Approach 1:
The patent establishes specific parameter ranges for average active hydrogen concentration (0.50 to 3.50 mol/kg for compound B, and 2.00 to 8.00 mol/kg for compound B and water combined). These defined parameters provide clear manufacturing targets that balance bonding strength improvement with compositional controllability, avoiding the pitfalls of both too-low and excessively high active hydrogen concentrations.
Solution Approach 2:
The patent uses a moderate range of active hydrogen concentration (0.50 to 3.50 mol/kg) rather than maximizing it completely. This partial action approach achieves sufficient bonding strength while maintaining manufacturing precision and avoiding the negative effects of excessive active hydrogen concentration, such as uncontrolled reaction rates or composition instability.
3Strength
If the ratio of isocyanate groups to active hydrogens is adjusted to optimize adhesion, then the adhesive properties improve, but the formulation becomes more complex
Solution Approach 1:
The patent controls the ratio of isocyanate groups to active hydrogens through the specified average active hydrogen concentration parameters. By defining these ratio parameters within specific ranges, the patent optimizes the stoichiometry of the curing reaction, ensuring complete reaction of isocyanate groups while maintaining formulation manageability and avoiding excessive complexity.
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 excellent adhesive properties, as demonstrated by improved creep test results and shear strength, indicating superior bonding capabilities compared to conventional compositions.
Implementation Method 1
a main agent containing a polyisocyanate component (A); and a curing agent containing water and an active hydrogen-containing compound (B) having a plurality of active hydrogens
Implementation Method 2
a ratio R2 of a number of isocyanate groups of the polyisocyanate component (A) to a number of active hydrogens (B-H) of the active hydrogen-containing compound (B) (NCO/H) is 1 to 5
Data Source
AI summary
There is provided a two-part urethane adhesive composition including: a main agent containing a polyisocyanate component (A); and a curing agent containing water and an active hydrogen-containing compound (B). The (B) contains a compound represented by Formula (4); the (A) contains a urethane prepolymer (A-3); an average active hydrogen concentration of the (B) is 0.50 to 3.50 mol/kg; an average active hydrogen concentration of the (B) and the water is 2.00 to 8.00 mol/kg. The main agent and the curing agent are mixed in such amounts as to satisfy conditions that: a ratio of the number of isocyanate groups of the (A) to the number of active hydrogens of the (B) is 1 to 5; and a ratio of the number of isocyanate groups of the (A) to the total number of active hydrogens of the (B) and the water is 0.5 to 2.5.