Solvent-Free Aqueous Polyurethane Nail Polish
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Solution Overview
Problem
The existing processes for producing polyurethane dispersions often rely on organic solvents, which are undesirable due to volatility, flammability, and environmental concerns, and there is a need for solvent-free and UV-curable options for nail polish compositions that provide functional flexibility and minimize the use of volatile organic compounds (VOCs).
Innovation Solution
Aqueous polyurethane dispersions are formed using isocyanate-terminated pre-polymers that undergo chain extension reactions with reactive diluents, eliminating the need for non-reactive solvents and allowing for UV curing, comprising components such as isocyanate-reactive ethylenically unsaturated components, diisocyanates, and hydroxyl group-containing compounds, with optional ionic groups for improved dispersion and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If organic solvents are used in polyurethane dispersion production, then the pre-polymer viscosity is reduced and dispersion is facilitated, but the process introduces volatility, flammability, environmental concerns, and requires solvent removal steps
Solution Approach 1:
The patent removes organic solvents from the polyurethane dispersion production process entirely, replacing them with water as the continuous phase. This extraction of the harmful organic component eliminates volatility and flammability while maintaining the ability to produce functional polyurethane dispersions for nail polish applications
Solution Approach 2:
The invention changes the fundamental parameter of the dispersion medium from organic solvent to water. This parameter change transforms the system from a harmful organic-based process to a safe aqueous system, while also enabling UV curability and eliminating the need for solvent removal steps
2Loss of substance
If distillation is used to remove organic solvents from polyurethane dispersions, then solvent content is reduced, but the process adds cost, complexity, and time to production
Solution Approach 1:
The patent eliminates the distillation step entirely by never introducing organic solvents in the first place. The aqueous dispersion is formed directly during polymerization, so no solvent removal process is needed, thereby eliminating the associated cost, complexity, and time
Solution Approach 2:
The invention performs the solvent removal action preliminarily by forming the dispersion in water from the start rather than adding organic solvents and then removing them. This preliminary formulation approach avoids the need for subsequent removal steps
3Quantity of substance
If acetone is used and recycled in polyurethane production, then cost is reduced, but wet acetone cannot be reused and separation adds cost, complexity and time
Solution Approach 1:
The patent removes acetone and all organic solvents from the process, replacing them with water. This eliminates the entire solvent recycling problem, as water-based dispersions do not require solvent separation or recycling infrastructure
Solution Approach 2:
The invention uses water as a disposable, non-recyclable medium that simplifies the process. Rather than investing in complex recycling systems for organic solvents, the aqueous system accepts water as a final component that requires no recovery, reducing overall process complexity
4Object-affected harmful factors
If UV-curable polyurethane dispersions are formulated without solvents, then VOC emissions are minimized and environmental friendliness is improved, but the formulation becomes more challenging
Solution Approach 1:
The patent creates a composite nail polish formulation combining UV-curable polyurethane acrylate dispersions with water and additional functional components. This composite approach integrates multiple functions (film formation, UV curability, adhesion) into a single solvent-free system that overcomes the challenges of formulating without organic solvents
Solution Approach 2:
The invention uses polyurethane acrylate dispersions that perform multiple functions: they provide the film-forming polymer, contain the UV curable groups for crosslinking, and serve as the dispersed phase in the aqueous system. This multi-functionality simplifies the overall formulation despite the constraints of being solvent-free and UV-curable
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 approach results in solvent-free, UV-curable polyurethane coatings for nail polish that offer enhanced scratch resistance, UV protection, and flexibility, while minimizing VOCs and eliminating the need for solvent removal processes, providing a more environmentally friendly and efficient production method.
Implementation Method 1
actinic radiation curable polyurethane dispersion... bearing ethylenic unsaturation end-groups... UV curable
Implementation Method 2
comprising a polyurethane polymer in at least one reactive diluent... and the said polyurethane polymer... is formed by chain extending at least one isocyanate-terminated ethylenically unsaturated polyurethane pre-polymer
Data Source
Figure 1
AI summary
A nail polish composition, in particular nail polish formulation, is disclosed which is based on a specific solvent-free aqueous polyurethane polymer dispersion, which is derived from at least one isocyanate-terminated ethylenically unsaturated polyurethane pre- polymer in a reactive diluent, after a chain extension reaction with a chain extender bearing isocyanate-reactive groups. The polyurethane pre-polymer comprises at least one (meth)acrylate functional group and at least one isocyanate functional group.