Marine Foam Buoyancy Stability Against Fuel Degradation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing polyurethane or polyisocyanurate foams fail to meet United States Coast Guard Title 33, Part 183 specifications regarding buoyancy after exposure to fully saturated gasoline vapor, reference fuel B, reference oil No. 2, and a 5% solution of Na3PO4, due to insufficient thermal, hydrolytic, and chemical stability.
Innovation Solution
A frothable foam composition blown by a low-pressure, high-boiling point HFC or HFO blowing agent, comprising a polyol blend with a significant proportion of polyether polyol and phthalic anhydride-based aromatic polyester polyol, along with plasticizers, flame retardants, surfactants, and catalysts, which maintains buoyant force within 5% of initial value after exposure to various challenging conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing polyurethane or polyisocyanurate foam formulations are used, then the foam provides basic buoyancy, but the buoyant force is reduced more than 5% after exposure to fully saturated gasoline vapor atmosphere, reference fuel B, reference oil No. 2, and a 5% solution of Na3PO4, failing to meet Coast Guard specifications
Solution Approach 1:
The patent modifies the chemical composition parameters of the foam by incorporating specific polyether polyols with controlled molecular weights and hydroxyl values, along with aromatic polyester polyols containing phthalic anhydride units. These compositional changes enhance the foam's resistance to fuel and chemical degradation while maintaining buoyancy stability after exposure to gasoline vapor, reference fuel B, reference oil No. 2, and Na3PO4 solutions.
Solution Approach 2:
The invention creates a composite polyol system combining polyether polyols (providing hydrolytic and chemical stability) with aromatic polyester polyols containing phthalic anhydride units (providing thermal stability and flame retardancy). This composite material approach allows the foam to simultaneously achieve resistance to multiple degradation mechanisms from fuel and chemical exposure while meeting Coast Guard buoyancy specifications.
2Temperature
If the foam composition is modified to increase thermal stability by increasing phthalic anhydride containing polyols, then thermal stability improves, but the foam must also maintain buoyancy in chemical environments, requiring a complex balance of multiple polyol components
Solution Approach 1:
The patent applies local quality by assigning specific functional roles to different polyol components: polyether polyols (30-70 wt.%) provide hydrolytic and chemical stability for resistance to fuel and aqueous solutions, while aromatic polyester polyols containing phthalic anhydride units (20-50 wt.%) provide thermal stability and flame retardancy. This functional differentiation within the polyol blend allows simultaneous optimization of thermal and chemical resistance properties without excessive complexity.
Solution Approach 2:
The invention establishes specific parameter ranges for the polyol blend composition to balance thermal and chemical stability: polyether polyols at 30-70 wt.% with molecular weights of 200-500 and hydroxyl values of 30-100 mg KOH/g, and aromatic polyester polyols at 20-50 wt.% with phthalic anhydride units providing thermal stability. These controlled parameter changes enable the foam to meet both thermal stability requirements and Coast Guard buoyancy specifications after chemical exposure.
3Object-affected harmful factors
If sucrose polyester polyol is eliminated to meet ASTM E-84 test standards for surface burning characteristics, then flame safety improves, but the foam formulation requires substitution with alternative polyols to maintain buoyancy and chemical resistance
Solution Approach 1:
The patent removes sucrose polyester polyol from the formulation to eliminate the issue of poor flame resistance and failure to meet ASTM E-84 test standards. This extraction of the problematic component necessitates substitution with alternative polyols that provide both the required flame safety and buoyancy performance.
Solution Approach 2:
The invention substitutes the eliminated sucrose polyester polyol with a controlled blend of polyether polyols (30-70 wt.%) and aromatic polyester polyols containing phthalic anhydride units (20-50 wt.%). This substitution maintains the foam's buoyancy properties and chemical resistance while achieving compliance with ASTM E-84 flame safety standards, thus resolving the formulation complexity issue.
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 foam composition effectively maintains buoyant force stability under stringent exposure conditions, adhering to Coast Guard specifications, with improved thermal and chemical stability and reduced degradation from solvents commonly encountered in marine environments.
Implementation Method 1
a polyurethane or polyisocyanurate foam blown by a blowing agent having a boiling point at atmospheric pressure of between ̃5° C. to ̃50° C.
Implementation Method 2
the buoyant force of the froth polyurethane or polyisocyanurate foam is not reduced more than 5% after exposure to being immersed in a fully saturated gasoline vapor atmosphere
Data Source
AI summary
The invention generally pertains to the use of polyurethane foam blown by at least one blowing agent having a boiling point at atmospheric pressure of between ˜5° C. to ˜50° C., including miscible blends thereof, which passes all United States Coast Guard Title 33, Part 183 specifications wherein the buoyant force of the froth polyurethane or polyisocyanurate foam is not reduced more than 5% after exposure to being immersed in a fully saturated gasoline vapor atmosphere, in reference fuel B, in reference oil No. 2, and in a 5% solution of Na3PO4.