Textile-Backed Polyurethane Foam Using Frothing and Blowing
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Solution Overview
Problem
Existing methods for producing frothed polyurethane carpet backings struggle to achieve densities below 11-12 pounds/cubic foot, limiting the range of carpet products with attached polyurethane cushions, and require additional materials or equipment to achieve lower densities, which increases costs and complexity.
Innovation Solution
A process forming a frothed polyurethane composition with specific ratios of polyols, water, physical blowing agents, fillers, and catalysts, allowing the composition to be applied and cured without a containment layer, utilizing both chemical and physical blowing agents to achieve densities as low as 176 grams/liter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a chemical blowing agent is used to create cellular structure in polyurethane foam, then gas generation occurs during curing reaction, but the reaction builds molecular weight and viscosity too rapidly to allow proper dispensing and gauging
Solution Approach 1:
The patent segments the blowing process into two distinct phases: (1) mechanical frothing phase where gas is incorporated during mixing without significant viscosity increase, and (2) curing phase where the foam sets in place. This separation allows the formulation to remain workable during application while still achieving the desired cellular structure during curing.
Solution Approach 2:
The patent performs the blowing action preliminarily by mechanically frothing the formulation before application. Gas is incorporated into the formulation during mixing, creating a frothed state that maintains workable viscosity. This preliminary gas incorporation avoids the rapid viscosity build that would occur if chemical blowing agents reacted during dispensing.
2Quantity of substance
If a physical blowing agent is used to create cellular structure, then gas formation occurs during curing, but elevated temperature required for volatilization also increases cure rate, making sequencing difficult
Solution Approach 1:
The patent segments the blowing and curing processes by using mechanical frothing to establish the cellular structure before curing begins. This eliminates the need to sequence thermal blowing with curing, as the gas structure is already in place during mixing and application.
Solution Approach 2:
The patent replaces thermal/chemical blowing mechanisms with a mechanical frothing system. Instead of relying on temperature-driven volatilization of physical blowing agents or chemical reactions during curing, the formulation is mechanically frothed to incorporate gas, which then stabilizes during the curing process.
3Loss of time
If frothed polyurethane system is used to allow slow initial cure for proper application, then density cannot be reduced below 11-12 pounds/cubic foot without additional containment layers
Solution Approach 1:
The patent changes the formulation parameters by incorporating specific amounts of water (0.1-1.0 parts per 100 parts polyol) and physical blowing agents (3-10 parts per 100 parts polyol) to control the expansion characteristics. These parameter adjustments enable the foam to achieve lower densities while maintaining structural integrity without containment layers.
Solution Approach 2:
The patent creates a composite blowing system that combines water (chemical blowing agent) with physical blowing agents (hydrocarbons, fluorocarbons, or hydrofluorocarbons). This composite approach allows synergistic control of gas generation and foam structure, achieving densities below 11 pounds/cubic foot while maintaining processability.
4Quantity of substance
If water is added to frothed polyurethane formulation to reduce density, then gas generation increases, but gas escapes through the exposed surface resulting in high loss of blowing efficiency
Solution Approach 1:
The patent optimizes the water content parameter to a specific range (0.1-1.0 parts per 100 parts polyol) that generates sufficient gas for density reduction while minimizing excessive expansion. This controlled water addition, combined with physical blowing agents, achieves lower densities without causing gas escape losses.
Solution Approach 2:
The patent uses physical blowing agents as intermediaries that work synergistically with water. These agents provide controlled gas generation that complements the water-based blowing, allowing the formulation to achieve target densities while maintaining blowing efficiency through coordinated gas release.
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
This process enables the production of low-density polyurethane cushions with improved softness and resilience, suitable for commercial-scale implementation, without the need for containment layers, reducing material and operational costs while maintaining better cushioning properties.
Implementation Method 1
A chemical blowing agent reacts under the conditions of the curing reaction to generate a gas. The most commonly used chemical blowing agent is water which, in addition to generating a gas (carbon dioxide) reacts with isocyanate groups to produce urea linkages
Implementation Method 2
Physical blowing agents are low-boiling liquids which volatilize under the curing conditions to form the blowing gas
Implementation Method 3
A gas is whipped into the foam formulation before it is applied to the textile
Data Source
AI summary
Textiles backed with a polyurethane cushion are produced by applying a layer of frothed polyurethane-forming mixture to a surface of the textile. The mixture contains both water and a physical blowing agent. The layer expands due to the action of the water and the physical blowing agent and cures to form an attached cushion having a density of 176 g/L or less.