Pipe Liner Resin Composition for Delayed Heat-Triggered Curing
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Solution Overview
Problem
Epoxy resin compositions with nitrogen-containing hardeners have limited storage stability due to premature reactivity at low temperatures, leading to short pot life and potential exothermic reactions, which complicates handling and application, especially in wet conditions where adhesion issues arise.
Innovation Solution
A delayed curing resin composition combining cyclic anhydrides, bisphenol A, and bisphenol F resins with a proprietary activator component that allows for indefinite delay of curing until elevated heat is applied, enabling extended shelf life up to six months and adhesion to wet surfaces.
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 patent divides the curing system 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 during storage while maintaining high curing reactivity when needed.
Solution Approach 2:
The patent introduces an intermediary substance (such as a dormant hardener or reaction inhibitor) that mediates between the epoxy resin and the nitrogen-containing hardener. This intermediary prevents premature reaction at low temperatures during storage but allows the curing reaction to proceed when activated by heat or other external stimuli.
2Duration of action of moving object
If epoxy resin and hardener are mixed for extended period, then pot life is extended, but curing reactivity deteriorates
Solution Approach 1:
The patent changes the temperature parameter to control the curing reaction. By storing and handling the mixed composition at low temperatures, the curing reaction is suppressed, extending pot life. When elevated temperature is applied during installation, the curing reactivity is activated and proceeds rapidly to completion.
3Strength
If epoxy coating is applied to wet surfaces, then adhesion should be maintained, but premature curing occurs leading to adhesion failure
Solution Approach 1:
The patent uses temperature as a control parameter to decouple adhesion requirements from curing. The composition can be applied to wet surfaces at low temperatures where the curing reaction is suppressed, allowing proper adhesion development. Subsequent heating activates the curing reaction without compromising the already-formed adhesive bond.
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 premature curing, ensuring reliable adhesion and curing on wet surfaces, and extending the shelf life to 90 days without exothermic reactions, enhancing safety and installation flexibility.
Implementation Method 1
a resin composition that allows the resin and catalyst to be mixed for an extended period creating a long pot life composition which cures only when subjected to elevated temperature
Implementation Method 2
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
Implementation Method 3
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.