One-Component Epoxy Adhesive Low-Temperature Curing
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Solution Overview
Problem
One-component thermosetting epoxy resin adhesives fail to meet requirements of good adhesion and stress resistance on metal substrates, especially at low curing temperatures below 170°C, as per the Ford Standards Testing procedure.
Innovation Solution
A one-component thermosetting epoxy resin adhesive composition comprising specific epoxy resin, epoxy novolac, latent hardener, accelerator, and toughness improver, with optimized weight percentages and components, which cures at temperatures between 100°C to 220°C, ensuring good adhesion and stress resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If conventional structural adhesives are used with low curing temperatures below 170°C, then energy consumption is reduced and processing time is shortened, but stress resistance and adhesion performance deteriorate
Solution Approach 1:
The patent modifies the chemical composition parameters of the adhesive system by incorporating specific catalysts (amine-based compounds with defined molecular weight and functionality), epoxy novolac resins (1-10 wt%), and toughness improvers (5-30 wt%). These parameter changes enable the adhesive to achieve proper curing and stress resistance at lower temperatures (100-170°C) without sacrificing performance.
Solution Approach 2:
The invention creates a composite adhesive system combining multiple components: base epoxy resin, catalyst (amine-based compound), epoxy novolac resin, and toughness improver. This composite formulation synergistically enhances both low-temperature curing capability and stress resistance, resolving the contradiction between energy efficiency and reliability.
2Loss of time
If conventional structural adhesives are used with low curing temperatures below 170°C, then production time is reduced, but adhesion on metal substrates deteriorates
Solution Approach 1:
The patent adjusts formulation parameters by incorporating amine-based catalysts with specific molecular weights (100-500 g/mol) and functionalities (2-4), along with epoxy novolac (1-10 wt%) and toughness improvers (5-30 wt%). These parameter modifications enable rapid curing at low temperatures while maintaining strong adhesion to metal substrates through enhanced chemical bonding mechanisms.
Solution Approach 2:
The amine-based catalyst acts as an intermediary that facilitates the curing reaction between epoxy groups and hardener at lower temperatures. This catalyst mediates the chemical reaction, enabling fast curing kinetics while preserving adhesion strength on metal substrates through proper crosslink density and bond chemistry.
3Device complexity
If one-component epoxy resin adhesive is used for storage stability and ease of handling, then device complexity is reduced, but achieving good adhesion and stress resistance at low temperatures becomes more difficult
Solution Approach 1:
The patent incorporates all necessary curing components (catalyst, epoxy novolac, toughness improver) into the one-component adhesive formulation before application. This preliminary action ensures that the adhesive is self-sufficient and can cure properly at low temperatures without requiring separate hardener components, thus maintaining storage stability while achieving reliable stress resistance.
Solution Approach 2:
The invention creates a multi-component composite system within a single adhesive component, combining base resin, catalyst, epoxy novolac, and toughness improver in specific proportions. This internal composite structure enables the one-component system to achieve low-temperature curing and stress resistance that would otherwise require multi-component systems.
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 adhesive achieves high stress durability and mechanical properties, withstanding multiple cycles in the Ford FLTM BV 101-07 stress durability test and demonstrating enhanced shear strength, suitable for bonding heat-stable materials like metals and plastics in vehicle construction.
Implementation Method 1
c) at least one latent hardener B for epoxy resins
Implementation Method 2
d) preferably at least one accelerator C for epoxy resins
Data Source
AI summary
A one-component thermosetting epoxy resin adhesive, including a) at least one epoxy resin A of formula (II)wherein substituents R′ and R″ independently of one another are H or CH3 and index s has value of 0-12, fraction of epoxy resin A being from 20-70 wt.-%, based on total weight of one-component thermosetting epoxy resin adhesive; and b) at least one epoxy novolac EN of formulawhere R2=or CH2, R1=H or methyl and z=0-7, fraction of epoxy novolac EN being from 1-8 wt.-% based on total weight of one-component thermosetting epoxy resin adhesive; and c) at least one latent hardener B for epoxy resins; and d) at least one accelerator C for epoxy resins; and e) at least at least one toughness improver D, fraction of toughness improver D being from 5-40 wt.-%, based on total weight of one-component thermosetting epoxy resin adhesive.