One-Component Epoxy Resin Composition with Reduced Toxicity
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Solution Overview
Problem
Reactive epoxy resin systems used in adhesives and structural foams often contain toxic, irritating, or sensitizing components, requiring hazardous labeling and posing environmental and health risks, while high molecular weight alternatives may not meet viscosity and strength requirements for processing and curing.
Innovation Solution
A one-component epoxy resin composition comprising a mixture of reactive epoxy resins, including at least 10% by weight of an epoxy group-containing reaction product of epichlorohydrin with polypropylene glycol and at least 10% by weight of an epoxy group-containing reaction product of epichlorohydrin with a novolak resin, along with a latent hardener, which ensures optimal processability and adhesive strength without the need for hazardous labeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional reactive epoxy resin systems are used, then adhesive strength and structural properties are achieved, but toxic, irritating, and sensitizing components require hazardous labeling and pose health risks
Solution Approach 1:
The patent changes the molecular weight parameter of the epoxy resin system by using high molecular weight solids based on DGEBA and liquid epoxy-terminated polyethers with high epoxide equivalent weight. This parameter change reduces sensitizing potential and eliminates the need for hazardous labeling while maintaining adhesive strength through optimized resin composition and curing conditions
Solution Approach 2:
The patent creates a composite epoxy resin system combining high molecular weight DGEBA solids with liquid epoxy-terminated polyethers. This composite approach allows the system to achieve both low sensitivity (no hazardous labeling) and high adhesive strength by synergistically combining the properties of different epoxy resin components with optimized hardener selection
2Object-affected harmful factors
If high molecular weight epoxy resins are used to reduce sensitization, then labeling requirements are eliminated, but viscosity properties and strength properties after curing are compromised
Solution Approach 1:
The patent optimizes the molecular weight and epoxide equivalent weight parameters of the epoxy resin components. By selecting high molecular weight DGEBA solids and liquid epoxy-terminated polyethers with specifically controlled high epoxide equivalent weight, the system achieves low sensitizing potential while maintaining processable viscosity through precise parameter control
Solution Approach 2:
The patent formulates a composite epoxy system combining high molecular weight DGEBA solids with liquid epoxy-terminated polyethers. This composite structure balances the high viscosity of solids with the fluidity of liquids, achieving both reduced sensitization and acceptable processing viscosity while maintaining strength properties after curing
3Strength
If high molecular weight solid epoxy novolaks are used to achieve high epoxy functionality, then strength is improved, but room temperature processing becomes impossible due to high viscosity
Solution Approach 1:
The patent modifies the physical state parameter of the epoxy resin system by using a combination of solids and liquids with controlled molecular weights. This allows the system to achieve high epoxy functionality for strength while maintaining lower viscosity for room temperature or elevated temperature processing through optimized component selection and ratios
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 a balance of low toxicity, improved processability, and high adhesive strength, meeting technical requirements while avoiding hazardous labeling and reducing sensitizing potential, with viscosities below 3000 Pa*s and tensile shear strength above 8 MPa after curing.
Implementation Method 1
reactive epoxy resins which can be reacted with other molecules that are reactive towards epoxy groups (so-called hardeners) and thereby cured or hardened
Data Source
AI summary
The present invention relates to heat-curable compositions comprising a mixture of reactive epoxy resins which comprises, based on the composition of all of the epoxy resins, a) at least 10% by weight of a reaction product which contains epoxy groups and which is obtained from epichlorohydrin with polypropylene glycol having an epoxy equivalent weight of at least 250 g/eq, and b) at least 10% by weight of a reaction product which contains epoxy groups and which is obtained from epichlorohydrin with a novolac resin having an epoxy equivalent weight of at least 175 g/eq, and at least one latent hardener.