Delayed-Cure Epoxy Resin Composition for Pipe Liner Storage
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Solution Overview
Problem
Epoxy resin compositions with nitrogen-containing hardeners have limited storage stability due to reactivity at low temperatures, leading to premature curing and short pot life, and existing adsorption techniques fail to provide complete inertness and extended shelf life without exothermic reactions or product deterioration.
Innovation Solution
A resin composition combining cyclic anhydrides, bisphenol A, and bisphenol F with a proprietary activator component that delays curing indefinitely until heat activation, allowing for extended shelf life and adhesion to wet surfaces, enabling the blending and storage of a two-part epoxy composition for up to six months before installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If nitrogen-containing hardeners are used to cure epoxy resins, then curing reactivity is improved, but storage stability deteriorates due to premature reaction at low temperatures
Solution Approach 1:
The curing system is divided into separate components: the epoxy resin base and the nitrogen-containing hardener are stored separately and only mixed shortly before processing. This segmentation prevents premature reaction while maintaining high curing reactivity when needed.
Solution Approach 2:
An adsorbent material with internal pore structure and active pore sites (such as silica gel, activated charcoal, or certain types of carbon black) is introduced as an intermediary to adsorb the nitrogen-containing hardener. This adsorbed state controls the release and reaction of the hardener, preventing premature curing while enabling controlled curing when activated by heating to desorb the adsorbed component.
2Ease of operation
If adsorption techniques are used to control chemical reactions, then process control is improved, but complete inertness cannot be achieved leading to slow escape of chemical reagent
Solution Approach 1:
The system utilizes temperature as a critical parameter to control the adsorption-desorption equilibrium. At low temperatures, the adsorbent maintains strong adsorption of the nitrogen-containing hardener, providing near-complete inertness. When heating is applied, the parameter change triggers desorption and activates the curing reaction, achieving both complete inertness during storage and reliable curing when needed.
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 long pot life and stable storage for up to six months, preventing premature curing and ensuring reliable adhesion and curing on wet surfaces, reducing the risk of exothermic reactions and spontaneous combustion, and allowing for flexible installation and transportation without refrigeration.
Implementation Method 1
adsorption techniques have been used to control and modify various types of chemical reactions. These techniques usually involve adsorbing a chemical reagent in an adsorbent material. Commonly used adsorbent materials for this purpose are materials having internal pore structure and active pore sites, and can consist of silica gel, certain types of carbon black, activated charcoal, and the like.
Implementation Method 2
Heating the adsorbent and adsorbate product desorbs the adsorbate reagent reactant making it available for a reaction with a reacting component.
Data Source
AI summary
A resin composition and method for installing a pipe liner that allows the liner to be fully wet out with a resin and activator and stored for a period of up to six months prior to installation and curing. A method of lining a pipe with a delayed curing resin composition is also provided that includes fully wetting out a liner with a blended two part epoxy composition such that the liner can be transported in a wet out fashion, placed in a pipe to be lined and repositioned as needed without concern for the resin composition to begin curing.