Pipe Liner Epoxy Composition With Delayed Heat-Triggered Curing
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Solution Overview
Problem
Epoxy resin compositions with nitrogen-containing hardeners have limited storage stability due to reactivity at room temperature, leading to premature hardening and short pot life, and existing adsorption techniques fail to provide complete inertness, resulting in exothermic reactions and product deterioration.
Innovation Solution
A delayed curing epoxy resin composition combining cyclic anhydrides, bisphenol A, and bisphenol F resins with a proprietary activator component, allowing for extended shelf life up to six months and adhesion to wet surfaces, enabling the resin to be fully blended and stored before curing, which can be initiated by heat.
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 room temperature
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 prevents direct contact and reaction between the hardener and epoxy resin at room temperature, while allowing controlled release when heated to desorb the adsorbed component.
2Productivity
If the reactivity of the nitrogen-containing base is increased to improve curing speed, then pot life is shortened due to faster consumption of the composition
Solution Approach 1:
The curing process is made periodic through controlled heating cycles. The adsorbed hardener is released in a controlled manner when the mixture is heated, providing a sustained release of reactive component that maintains productivity while extending the working duration through controlled activation phases.
Solution Approach 2:
The physical state and reactivity of the hardener are changed by altering temperature parameters. At room temperature, the adsorbed hardener remains inert, but when heated to a specific temperature range, the adsorbate desorbs and becomes reactive, allowing control over both curing speed and pot life through temperature management.
3Stability of the object's composition
If adsorption techniques are used to control chemical reactions and extend pot life, then storage stability is improved, but complete inertness cannot be achieved leading to slow exothermic reactions and product deterioration
Solution Approach 1:
The adsorbent material creates an inert environment for the stored hardener by trapping it within its pore structure. This physical containment prevents spontaneous exothermic reactions during storage. When heating is applied, the controlled desorption occurs in a managed manner rather than through uncontrolled spontaneous reaction, eliminating the harmful exothermic effect during storage while maintaining reactivity 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, allowing for safe storage and transportation of wetted-out pipe liners without exothermic reactions, enabling flexible installation and extended shelf life without spontaneous combustion, with strong adhesion to wet surfaces and superior chemical resistance.
Implementation Method 1
adsorption 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
Implementation Method 2
subsequently heated to desorb the adsorbed component. Heating the adsorbent and adsorbate product desorbs the adsorbate reagent reactant making it available for a reaction
Implementation Method 3
After the two parts are mixed together, they begin a curing process that is typically triggered by exposure to heat, humidity or a ultra-violet light source, whereby the mixed material quickly begins to solidify
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.