Polyurethane Encapsulate Water Barrier Properties
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Solution Overview
Problem
Polyurethane coating films used for encapsulating water-soluble materials face challenges in controlling water absorption and water vapor transmission, which affects the release rate of encapsulated substances, and existing solutions do not adequately balance mechanical strength with water barrier properties.
Innovation Solution
A polyurethane film formed from a reaction product of an aromatic isocyanate and a polyol with at least 35 wt% butylene oxide based polyether polyol, which enhances hydrophobicity and reduces water absorption and vapor transmission without the need for additional components, maintaining mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polyurethane coating film is used to encapsulate water-soluble materials, then the encapsulation and controlled release function is achieved, but the water absorption and water vapor transmission cannot be adequately controlled
Solution Approach 1:
The patent adjusts the water absorbing capacity parameter of the polyurethane coating film by modifying the polyol composition, specifically incorporating polyols with lower water solubility to reduce water absorption while maintaining the controlled release function
Solution Approach 2:
The patent uses a composite polyol system combining multiple polyol components with different properties (polyester polyol, polyether polyol, and polycaprolactone polyol) to achieve both mechanical strength and reduced water absorption in the polyurethane coating film
2Productivity
If the water solubility of encapsulated material exceeds a specific level, then the release rate increases, but the polyurethane coating film absorbs excessive water
Solution Approach 1:
The patent changes the hydrophobicity parameter of the polyurethane coating film by selecting polyols with appropriate water solubility characteristics, allowing the coating to withstand higher water solubility materials without excessive water absorption
3Strength
If existing polyurethane coating formulations are used, then mechanical strength is achieved, but water barrier properties are insufficient
Solution Approach 1:
The patent employs a composite polyol formulation combining polyester polyol, polyether polyol, and polycaprolactone polyol in specific ratios to create a polyurethane coating that simultaneously achieves mechanical strength and improved water vapor barrier properties
Solution Approach 2:
The patent optimizes the molecular weight and hydroxyl value parameters of the polyol components to enhance both the mechanical properties and water barrier characteristics of the resulting polyurethane coating film
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 resulting polyurethane film exhibits improved water barrier properties, reduced water absorption, and maintained mechanical integrity, ensuring controlled release of encapsulated materials even in water-rich environments.
Implementation Method 1
which enhances hydrophobicity and reduces water absorption and vapor transmission
Data Source
AI summary
Embodiments relate to a polyurethane coating film that has improved water barrier properties combined with mechanical strength. According to embodiments, a polyurethane encapsulate includes a polyurethane film that is a reaction product of an aromatic isocyanate and a polyol, and the polyol includes a butylene oxide based polyether polyol in an amount of at least 35 wt% based on a total weight of the polyol. The polyurethane encapsulate further includes a particulate material that is enclosed by the polyurethane film.