Polyurethane Dispersion for Low-VOC Hair Styling
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Solution Overview
Problem
Conventional low-VOC hair setting compositions face challenges with stability, moisture resistance, and curl hold, particularly under high humidity, due to the use of hydrophilic polyurethanes and volatile amines, which affect the performance and safety of hair styling products.
Innovation Solution
The development of hair setting compositions using aqueous polyurethane dispersions with water-insoluble, non-water-dispersible isocyanate-functional prepolymers and amino-functional compounds containing sulfonate or sulfonic acid groups, which have low ionic group content and are formulated to provide high moisture resistance and excellent curl hold at low polyurethane concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If conventional acrylates are used in low-VOC hair setting formulations, then the proportion of volatile organic compounds is reduced, but the stability of the composition deteriorates (sedimentation, separation occur)
Solution Approach 1:
The patent changes the chemical parameters of the film-forming polymer by using polyurethanes with specific molecular weight ranges (400,000 to 5,000,000 g/mol) and specific structural characteristics instead of conventional acrylates. This parameter change allows the formulation to maintain stability while keeping VOC content low, as the polyurethane polymers provide inherent stability without requiring high proportions of volatile solvents for dispersion.
Solution Approach 2:
The patent employs composite material strategies by combining polyurethane polymers with specific additives and excipients formulated in a low-VOC system. The composition includes polyurethane (0.1-20%), polyol (15-85%), and various stabilizers and conditioners that work synergistically to maintain composition stability without relying on conventional high-VOC solvent systems.
2Device complexity
If conventional film-forming polymers are used, then the formulation is simpler, but moisture and water resistance deteriorates when hair contacts rain, sweat, or high humidity
Solution Approach 1:
The patent improves moisture resistance by changing the chemical composition parameters to include polyurethanes with specific hydrophobic characteristics and high molecular weights. These polymers form more water-resistant films on hair compared to conventional acrylates, while the formulation complexity is managed through systematic selection of compatible excipients and processing conditions.
3Reliability
If polyurethanes with high molecular weight are used to improve water resistance, then moisture resistance improves, but sprayability deteriorates
Solution Approach 1:
The patent optimizes sprayability despite using high molecular weight polyurethanes by carefully controlling the molecular weight distribution within the 400,000 to 5,000,000 g/mol range and adjusting formulation parameters such as polyol content (15-85%), temperature, and shear conditions during application. These parameter adjustments ensure the viscous polymer solution can be properly sprayed while maintaining water resistance.
4Loss of substance
If hydrophilic polyurethanes and volatile amines are used in low-VOC formulations, then VOC proportion is reduced, but performance under high humidity deteriorates (curl hold and stability)
Solution Approach 1:
The patent changes the hydrophilicity parameter of the polyurethane to achieve optimal balance between low-VOC formulation and high humidity performance. By selecting polyurethanes with specific hydrophobic-hydrophilic balance and eliminating volatile amines, the formulation maintains curl hold under humidity while keeping VOC proportions low.
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 solution achieves excellent curl hold and moisture resistance in high humidity conditions while reducing the use of volatile organic compounds, improving the stability and safety of hair styling products.
Implementation Method 1
reacting one or more water-insoluble, non-water-dispersible, isocyanate-functional polyurethane prepolymers with one or more amino-functional compounds
Data Source
Figure 1~2
AI summary
The invention relates to hair styling compositions containing special polyurethanes and to the use of the above-mentioned polyurethanes for producing hair styling compositions.