Polyurethane Coating Hydrolysis Stability Offshore
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Solution Overview
Problem
Existing polyurethane coatings for pipelines face challenges with hydrolysis stability at high temperatures, particularly in offshore oil extraction where temperatures exceed 100°C, and current solutions like polyisocyanurates and epoxy-based materials have limitations in long-term stability and processing difficulties.
Innovation Solution
A method involving the reaction of polyepoxides with polyetheramines or polyetherols to produce isocyanate-reactive compounds, which are then combined with polyisocyanates, optimizing the ratio of NH/OH groups to epoxy groups within specific ranges to enhance hydrolysis stability and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If aromatic isocyanates are used in polyether polyurethanes, then the coating provides good insulation properties, but the urethane bond hydrolyzes at higher temperatures reducing long-term stability
Solution Approach 1:
The patent changes the chemical parameters of the polyol component by reacting polyepoxides with polyetheramines or polyetherols to create isocyanate-reactive compounds with modified molecular structure. This parameter change allows the urethane bonds to resist hydrolysis at high temperatures while maintaining the insulation properties of aromatic isocyanate-based polyurethanes.
2Temperature
If polyisocyanurates are used to improve temperature stability, then better temperature resistance is achieved, but the system reacts particularly quickly making filling difficult and the material becomes brittle
Solution Approach 1:
The patent modifies the reactivity parameters of the polyol component through controlled reaction of polyepoxides with polyetheramines or polyetherols. By adjusting the ratio of NH or OH groups to epoxy groups and controlling molecular weight, the patent achieves moderate reactivity that allows sufficient fill time while maintaining temperature stability, avoiding the excessive cross-linking and brittleness of polyisocyanurates.
3Strength
If higher functional high molecular weight polyols are used with epoxy resin, then improved mechanical properties are achieved, but the high viscosity makes processing difficult and long-term hydrolysis stability is insufficient
Solution Approach 1:
The patent segments the polyol structure by controlling the molecular weight and functionality of the reaction products from polyepoxide-polyetheramine or polyepoxide-polyetherol reactions. This segmentation creates a polyol with balanced molecular characteristics that provides good mechanical properties while maintaining lower viscosity for easier processing compared to high molecular weight polyols.
4Reliability
If the ratio of NH or OH groups to epoxy groups is increased, then hydrolysis stability is improved, but the reaction speed increases making filling difficult
Solution Approach 1:
The patent optimizes the stoichiometric parameters by controlling the ratio of NH or OH groups to epoxy groups within a specific range. This parameter optimization balances the hydrolysis stability improvement with acceptable reaction speed, allowing sufficient time for filling large volumes while achieving the desired long-term stability.
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 method achieves hydrolysis stability comparable to pure epoxy elastomers while maintaining the processing advantages of polyurethanes, providing excellent mechanical properties and elongation at high temperatures, suitable for offshore applications.
Implementation Method 1
the compound (P1) being available or is obtained by reacting at least one polyepoxide with a compound (V1) selected from the group consisting of polyetheramines and polyetherols
Implementation Method 2
comprising the reaction of a composition (Z1) comprising at least one isocyanate-reactive compound (P1), and a composition (Z2) comprising at least one polyisocyanate
Implementation Method 3
the urethane bond can also hydrolyze at higher temperatures... improved hydrolysis stability of the coating
Data Source
AI summary
The present invention relates to a method for producing a polyurethane, comprising the reaction of a composition (Z1) at least comprising a compound (P1) that is reactive to isocyanates, and a composition (Z2), at least comprising a polyisocyanate, wherein the compound (P1) is or can be obtained through the reaction of at least one polyepoxide with a compound (V1) selected from the group consisting of polyetheramines and polyetherols. The present invention further relates to polyurethanes that are or can be obtained according to a method of this type, and the use of a polyurethane according to the invention for coating of piping, as a "field joint" or of underwater technology (subsea equipment) such as, for example, a "Christmas tree" for the off-shore field, as well as glass-syntactic polyurethane.