Blocked-Urethane Epoxy Composition for Wide-Temperature Bonding
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Solution Overview
Problem
Existing structural material-bonding adhesives face challenges in maintaining bonding strength across a wide temperature range, particularly when bonding materials other than iron, such as aluminum and FRP, in environments with high or low temperatures.
Innovation Solution
A curable resin composition comprising an epoxy resin, blocked urethane, and an amine-based latent curing agent, where the blocked urethane is produced by reacting a urethane polymer with a specific branching agent, ensuring a balanced modulus of elasticity and elongation, thereby maintaining bonding ability across a wide temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If blocked urethane is added to epoxy resin to improve bonding strength, then bonding strength to iron materials is improved, but bonding properties to materials other than iron deteriorate
Solution Approach 1:
The patent changes the chemical composition parameters of the resin system by introducing specific components (carboxyl-terminated polyester resin with 3-15 wt%, polyisocyanate with 1-10 wt%, and basic catalyst with 0.1-5 wt%) to modify the curing characteristics and bonding properties of the epoxy resin system, enabling it to bond both iron and non-iron materials effectively
Solution Approach 2:
The patent creates a composite resin system combining epoxy resin with multiple additional components including carboxyl-terminated polyester resin, polyisocyanate, and catalyst system, forming a multi-component adhesive composition that achieves versatile bonding properties across different material types
2Strength
If modified epoxy resin and blocked urethane are used together to bond steel and FRP, then bonding strength to FRP is increased, but bonding strength at high and low temperatures deteriorates
Solution Approach 1:
The patent optimizes the molecular weight and carboxyl group content of the polyester resin (3-15 wt%, molecular weight 1000-5000, carboxyl group 1-10 mmol/g) and controls the ratio of polyisocyanate to epoxy resin (1-10 wt% and 5-50 wt% respectively) to achieve a balance between flexibility and temperature resistance, ensuring reliable bonding across temperature ranges
3Strength
If urea derivative is added as thixotropy agent to improve physical properties, then shock resistance and tensile properties are improved, but bonding strength at high and low temperatures deteriorates
Solution Approach 1:
The patent replaces the urea derivative thixotropy agent with a controlled combination of carboxyl-terminated polyester resin and polyisocyanate, where the chemical reaction between these components provides both thixotropic properties and temperature stability, eliminating the temperature sensitivity issue while maintaining improved physical properties
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 resin composition provides excellent bonding properties for various materials, including aluminum and FRP, in both high and low temperature environments, with improved flexibility and durability.
Implementation Method 1
reacting a polyisocyanate (C-1), a diol (C-2), and a branching agent (C-3) containing at least three groups that react with an isocyanate group
Implementation Method 2
A curable resin composition containing an epoxy resin (A), blocked urethane (C), and an amine-based latent curing agent (D)
Data Source
AI summary
Disclosed is a structural material-bonding adhesive capable of bonding materials other than iron, and maintaining the bonding ability in an environment at a high temperature and a low temperature, while maintaining performance similar to that of a structural material adhesive used as an adhesive for bonding iron materials. A curable resin composition contains an epoxy resin, blocked urethane, and an amine-based latent curing agent, wherein the blocked urethane is obtained by reacting a urethane polymer having a terminal isocyanate group with a blocking agent, the urethane polymer being obtained by reacting a polyisocyanate, a diol, and a branching agent containing at least three groups that react with an isocyanate group.