Curable Adhesive Composition for Flexible Substrates
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Solution Overview
Problem
Current curable adhesive compositions often require long aging periods to achieve high adhesive strength and lack flexibility and durability after curing, especially when using bisphenol F epoxy resin without bisphenol A and epoxy acrylate components.
Innovation Solution
A curable adhesive composition is developed containing a bisphenol F epoxy resin and bisphenol A epoxy resin in a specific weight ratio, combined with a rubber modified bisphenol and an epoxy acrylate component, which enhances toughness, adhesion, and flexibility by incorporating a rubber modified epoxy resin and epoxy acrylate, allowing for rapid curing and improved durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a photoreactive adhesive composition contains only bisphenol F epoxy resin without bisphenol A and epoxy acrylate components, then the composition can be formulated with simpler ingredients, but the adhesive strength after curing is insufficient and the cured product lacks flexibility and durability
Solution Approach 1:
The patent applies composite materials by combining three distinct epoxy resin components (bisphenol F epoxy resin, bisphenol A epoxy resin, and epoxy acrylate) in specific weight ratios. This composite formulation creates a synergistic effect where each component contributes different properties: bisphenol F provides flexibility and stress relaxation, bisphenol A provides structural strength, and epoxy acrylate enhances adhesion and curing speed. The combination resolves the contradiction by achieving superior adhesive strength and durability while maintaining a manageable formulation complexity through defined ratio ranges.
Solution Approach 2:
The patent applies parameter changes by optimizing the weight ratios of the three epoxy components within specific ranges (bisphenol F: 70-90 parts, bisphenol A: 5-20 parts, epoxy acrylate: 5-15 parts per 100 parts total). By adjusting these parameters, the formulation achieves the optimal balance between adhesive strength, flexibility, and durability. This systematic parameter optimization resolves the contradiction by demonstrating that controlled complexity in formulation ratios leads to significant improvements in performance.
2Device complexity
If the adhesive composition uses conventional epoxy resins without rubber modification, then the formulation is simpler, but the cured adhesive lacks flexibility and toughness
Solution Approach 1:
The patent applies parameter changes by incorporating rubber-modified bisphenol A epoxy resin within a specific weight ratio range (5-20 parts per 100 parts total epoxy resin). The rubber modification introduces flexible polymer chains into the rigid epoxy structure, fundamentally changing the mechanical properties of the cured adhesive. This controlled addition of rubber modification (5-20% by weight) provides the necessary flexibility and toughness while maintaining formulation simplicity through defined ratio specifications.
3Device complexity
If the adhesive requires prolonged aging to achieve high bond strength, then the curing mechanism is simpler, but the productivity and time efficiency are reduced
Solution Approach 1:
The patent applies parameter changes by incorporating epoxy acrylate component (5-15 parts per 100 parts total epoxy resin) which introduces acrylate functional groups capable of rapid photopolymerization. This component changes the curing kinetics by enabling fast initial bond formation through UV-triggered polymerization, significantly reducing the time required to achieve handling strength. The specific ratio range ensures rapid curing while maintaining the overall curing mechanism simplicity through photo-initiated polymerization.
Solution Approach 2:
The patent applies continuity of useful action by designing a dual-cure system where the epoxy acrylate component provides immediate photopolymerization upon UV exposure, creating initial bond strength continuously. Simultaneously, the bisphenol F and bisphenol A epoxy resins continue to cure and crosslink over time, providing ongoing strength development. This continuous curing process eliminates idle time and ensures progressive strength gain without requiring prolonged aging, thereby improving productivity while maintaining curing mechanism simplicity.
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 high adhesive strength immediately after lamination, exhibits excellent flexibility and durability, and reduces the need for prolonged aging, with improved resistance to hydrophilic liquids and stress relaxation.
Implementation Method 1
it is not required that the cationically curable adhesive is irradiated continually until it is fully cured. In fact, once such an adhesive is irradiated, curing reaction in which radiation-generated cationic active species participate goes ahead even when this irradiation is stopped.
Data Source
AI summary
A thermally or photo curable adhesive composition containing a bisphenol F epoxy resin and a bisphenol A epoxy resin in a ratio between 2 and 10. The composition further contains at least one epoxy acrylate component and a rubber modified bisphenol. The adhesive composition is applicable by a melt or liquid coating technique and undergoes curing upon exposure to heat or radiation, showing improved viscoelastic properties and suitable to provide a cured product having superior durability.