Polyurethane Foam Formulation for Automotive Fender Weight Reduction
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Solution Overview
Problem
Incumbent polyurethane foams for automotive fenders have high density, which increases production costs and weight, and lack the necessary balance of reactivity, adhesion to polymer films, and self-crushing properties.
Innovation Solution
A formulation comprising two different polyoxypropylene polyols and an isocyanate-terminated prepolymer composition with specific reactants, such as diphenylmethane diisocyanate and carbodiimide-modified diphenylmethane diisocyanate, to produce a polyurethane foam with reduced density, improved adhesion, and self-crushing properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the density of polyurethane foam is reduced to lower cost and weight, then weight and cost decrease, but adhesion to polymer films and other properties such as hardness and surface appearance may be compromised
Solution Approach 1:
The patent changes the chemical parameters of the polyol composition by specifying two different polyoxypropylene polyols with particular equivalent weights (400-800 and 150-300) and functionality ranges (2-3.8 and 4.5-8). These parameter changes enable the foam to achieve lower density (50-110 kg/m³) while maintaining adhesion strength of at least 9 N through optimized molecular structure and reactivity.
2Duration of action of moving object
If the reaction time is extended to allow sufficient handling time, then handling time increases, but processing speed and productivity decrease
Solution Approach 1:
The patent optimizes the reactivity parameters by selecting polyols with specific equivalent weights and functionalities, and matching them with isocyanates containing 10-48 wt% NCO. This parameter optimization creates a balanced reaction profile where the foam has sufficient initial reaction time to fill mold cavities completely, then cures rapidly within 60 seconds to enable quick demolding and high productivity.
3Ease of manufacture
If incumbent polyurethane foam formulations are used, then processing experience is available, but density is high (120-150 kg/m3) and self-crushing properties are insufficient
Solution Approach 1:
The patent fundamentally changes the composition parameters by employing two different polyoxypropylene polyols with specific properties rather than conventional single polyol systems. This parameter change reduces foam density to 50-110 kg/m³ while maintaining processability through controlled reactivity, and achieves self-crushing behavior through optimized cell structure formation.
Solution Approach 2:
The patent creates a composite polyol system combining two different polyoxypropylene polyols with distinct characteristics (different equivalent weights and functionalities). This composite approach allows the formulation to achieve multiple desirable properties simultaneously: lower density, adequate adhesion, proper reactivity balance, and self-crushing capability that cannot be obtained with single polyol systems.
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 formulation achieves a polyurethane foam with a density of 50-110 kg/m3, sufficient peel adhesion strength, and self-crushing capability, allowing for efficient processing and aesthetic quality suitable for automotive applications.
Implementation Method 1
Through polymerization a polyurethane foam forms and expands
Implementation Method 2
a polyurethane foam forms and expands, adopting the shape of the mold
Data Source
AI summary
A novel formulation for preparing a polyurethane foam with low density, desirable hardness, good appearance, and good adhesion to a polymer film without compromising the processing properties of the formulation; and a process for preparing a multilayer structure made of the polyurethane foam.