Epoxy Filter Material Curing for Low Emissions
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Solution Overview
Problem
Filter materials for automotive and industrial applications face challenges in achieving strength and rigidity without releasing phenol or formaldehyde into the environment, as existing binders like phenolic resins and synthetic resin dispersions either release harmful substances during curing or reduce filtration permeability.
Innovation Solution
A filter material using an epoxy resin impregnation with a combination of cold-curing and hot-curing hardeners, which allows for gradual curing and prevents phenol and formaldehyde release, maintaining flexibility and strength while resisting aggressive influences at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If phenolic resin binders are used to achieve strength and rigidity, then the filter material becomes strong and rigid, but phenol and formaldehyde are released into the environment during processing and use
Solution Approach 1:
The patent changes the chemical composition parameters by replacing phenolic resin with epoxy resin and using specific hardeners (polyamidoamine or polyamide) that do not release harmful substances. This parameter change maintains the required strength and rigidity while eliminating phenol and formaldehyde release during processing and use.
Solution Approach 2:
The patent creates a composite binder system combining epoxy resin with specific hardeners (polyamidoamine or polyamide) to achieve the desired mechanical properties without the harmful release characteristics of phenolic resins. This composite approach provides both strength and environmental compatibility.
2Object-generated harmful factors
If synthetic resin dispersions are used as binders to avoid phenol and formaldehyde release, then harmful substance release is reduced, but the binder forms films during drying that reduce pore diameter and permeability
Solution Approach 1:
The patent changes the binder type from synthetic resin dispersions to epoxy resin with specific hardeners, which fundamentally alters the drying behavior. This parameter change prevents film formation during drying while maintaining low permeability loss, as epoxy resin does not form the same type of blocking films as synthetic dispersions.
3Strength
If phenolic resin is used to achieve initial strength for processing, then the filter material becomes stiff enough for grooving and folding, but the resin is usually over-cured and becomes brittle during further processing
Solution Approach 1:
The patent changes the curing kinetics parameters by using epoxy resin with specific hardeners that provide controlled, gradual curing rather than rapid over-curing. This parameter change allows the filter material to achieve sufficient initial strength for processing while avoiding brittleness, as the curing reaction progresses more controllably.
4Object-generated harmful factors
If epoxy resin is used to avoid phenol and formaldehyde release, then harmful substance release is eliminated, but epoxy resin requires hot-curing hardeners that react slowly and require prolonged drying time
Solution Approach 1:
The patent merges cold-curing and hot-curing hardening mechanisms by using epoxy resin with both cold-curing and hot-curing hardeners. This combination allows the filter material to achieve initial set at lower temperatures (reducing drying time) while still benefiting from the slow, controlled curing characteristics that prevent harmful releases and ensure final strength.
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 epoxy resin-based filter material achieves superior resistance to hot engine oil, fuels, and aggressive substances without releasing phenol or formaldehyde, with improved processing properties and filtration performance compared to phenolic resin-impregnated materials.
Implementation Method 1
the resin is usually over-cured. The curing reaction is not easy to control and the resin is usually over-cured. The filter material can therefore become brittle.
Implementation Method 2
After the process of embossing and folding, the bellows is placed in a curing oven to completely harden the resin.
Implementation Method 3
They should also withstand aggressive environmental conditions and high temperatures.
Data Source
AI summary
The invention relates to a single or multi-layer filter material, comprising at least one layer made of cellulose, glass fiber, synthetic fiber, or a mixture thereof, and saturated with a binding agent made of an epoxy resin and a curing agent. The hardening agent comprises a first hardener cross-linking at a lower temperature, and a second hardener cross-linking at a higher temperature, so that the epoxy resin can be hardened stepwise depending on the temperature.