Curable Composition for Structural Bonding Thermal Strain
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current adhesive compositions struggle to achieve a balance between high strength, rigidity, and flexibility necessary for structural bonding of dissimilar materials like steel, aluminum, and fiber-reinforced composites, particularly in addressing thermal strain due to differing linear expansion coefficients.
Innovation Solution
A multi-pack curable composition comprising a polyoxyalkylene polymer with trifunctional reactive silicon groups, a (meth)acrylate ester polymer, and an epoxy resin curing agent with a tertiary amine, optimized in weight ratios and monomer compositions to produce a cured product with high Young's modulus and elongation at break, ensuring flexibility and strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an epoxy resin with high rigidity is used as adhesive, then bonding strength is improved, but flexibility to follow thermal strain deteriorates
Solution Approach 1:
The invention uses a composite adhesive system combining epoxy resin with reactive silicon group-containing polymers (polyoxyalkylene polymer and (meth)acrylate ester polymer). This composite formulation achieves both high bonding strength from the epoxy resin and flexibility to accommodate thermal strain from the polymer components, resolving the contradiction between strength and adaptability.
Solution Approach 2:
The invention modifies the chemical composition parameters of the adhesive by incorporating specific ratios of epoxy resin, polyoxyalkylene polymer with reactive silicon groups, and (meth)acrylate ester polymer. By adjusting these compositional parameters, the adhesive achieves optimal balance between rigidity (for strength) and flexibility (for thermal strain accommodation).
2Adaptability or versatility
If a reactive silicon group-containing polyoxyalkylene polymer is used to improve flexibility, then flexibility is improved, but bonding strength deteriorates
Solution Approach 1:
The invention merges three distinct components: epoxy resin (for strength), polyoxyalkylene polymer with reactive silicon groups (for flexibility and adhesion), and (meth)acrylate ester polymer (for enhanced mechanical properties). The synergistic combination of these components resolves the contradiction by allowing each component to contribute its advantageous properties without compromising the others.
3Strength
If polyoxyalkylene polymer with multiple reactive silicon groups at one terminal is used, then strength is improved, but obtaining cured product with both high rigidity and flexibility becomes difficult
Solution Approach 1:
The invention distributes different functional properties to different components: the polyoxyalkylene polymer with multiple reactive silicon groups provides localized strength enhancement at bonding interfaces, while the (meth)acrylate ester polymer and epoxy resin matrix provide the overall rigidity and flexibility balance. This local quality assignment simplifies achieving the dual properties of rigidity and flexibility.
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 provides a cured product with enhanced adhesive strength, rigidity, and flexibility, effectively addressing thermal strain issues by maintaining high Young's modulus and elongation at break, making it suitable for structural bonding of dissimilar materials.
Implementation Method 1
a reactive silicon group represented by a general formula (1)... -SiX3 (where X represents a hydroxyl group or a hydrolyzable group)
Implementation Method 2
a silanol condensation catalyst (E)... B agent containing an epoxy resin (C) and a silanol condensation catalyst (E)
Implementation Method 3
an epoxy resin curing agent (D) having a tertiary amine... B agent containing an epoxy resin (C)
Data Source
AI summary
Provided is a curable composition in which a cured product after curing has high strength, high rigidity, and flexibility, and a cured product obtained by curing the curable composition. A multi-pack curable composition including an A agent containing a polyoxyalkylene polymer (A) having a trifunctional reactive silicon group, a (meth)acrylate ester polymer (B) having a trifunctional reactive silicon group, and an epoxy resin curing agent (D) having a tertiary amine, and a B agent containing an epoxy resin (C) and a silanol condensation catalyst (E), in which a weight ratio of (A):(B) is 95:5 to 50:50, a weight ratio of a total of (A) and (B):(C) is 90:10 to 50:50, and (B) contains a polymer containing 40% by weight or more of alkyl (meth)acrylate having 1 to 3 alkyl carbon atoms in a total monomer.