Core-Shell Polymeric Particles Void Retention
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Solution Overview
Problem
Existing processes for forming core-shell polymeric particles are inefficient and costly, requiring cooling or waiting for the first shell process to complete, which limits the temperature range for forming such particles.
Innovation Solution
A core-shell polymeric particle composition with a core containing a void, a first shell polymer with a glass transition temperature greater than 50 °C, and a second shell polymer with a temperature range of -60 °C to 50 °C, formed between 30 °C lower than the first shell's Tg and 100 °C, allowing for higher temperature processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the second shell polymer is formed at a temperature at least 30 °C lower than the Tg of the first shell polymer, then the first shell structure is maintained, but the processing efficiency is reduced and production costs increase due to cooling requirements
Solution Approach 1:
The patent changes the temperature parameter for forming the second shell polymer from the conventional low-temperature process (at least 30°C lower than Tg of first shell) to a higher temperature process (between 0°C and 30°C lower than Tg, and optionally from -60°C to 100°C). This parameter change eliminates the need for cooling between stages, improving processing efficiency while still maintaining first shell structure through controlled temperature selection that preserves the glass transition properties of the first shell polymer.
2Productivity
If the second shell polymer is formed at higher temperatures (0°C to 30°C lower than Tg of first shell polymer), then processing efficiency improves, but the first shell structure may be compromised
Solution Approach 1:
The patent optimizes the temperature parameter within a specific range (0°C to 30°C lower than Tg of first shell polymer) that balances processing efficiency and structural integrity. By selecting temperatures within this optimized range, the process achieves high efficiency without compromising the first shell structure, as the temperature remains sufficiently below the Tg to prevent unwanted structural changes.
Solution Approach 2:
The patent employs feedback control by monitoring and adjusting the polymerization temperature based on the Tg of the first shell polymer. The temperature is dynamically selected to maintain an appropriate differential (0°C to 30°C lower than Tg), ensuring that the first shell structure is preserved while enabling efficient high-temperature processing of the second shell.
3Adaptability or versatility
If the temperature range for forming the second shell is extended to -60°C to 100°C, then process flexibility and energy efficiency improve, but control over particle structure becomes more difficult
Solution Approach 1:
The patent establishes a broad temperature range (-60°C to 100°C) for forming the second shell polymer, providing exceptional process flexibility and energy efficiency. Within this broad range, specific sub-ranges can be selected to achieve different structural outcomes, allowing optimization for various application requirements while maintaining adequate structural control through the fundamental constraint that the temperature remains below the Tg of the first shell polymer.
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
Enables energy savings and improved opacity in dry compositions, providing binding functionality and integrity to films while maintaining the benefits of void retention in the particles.
Implementation Method 1
the first shell polymer having a glass transition temperature (Tg) greater than 50 °C
Implementation Method 2
the second shell polymer having a Tg of from -60 °C to 50 °C
Data Source
AI summary
A polymeric particle including a core, a first shell, and a second shell is provided: the core including, when dry, at least one void; the first shell polymer having a calculated glass transition temperature("Tg") greater than 50 °C and including, as polymerized units, from 15% to 60%, by weight based on the weight of the first shell, monomer selected from the group consisting of acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, and mixtures thereof; and from 0.3% to 10%, by weight based on the weight of the first shell polymer, multiethylenically unsaturated monomer; and the second shell polymer having a Tg of from -60 °C to 50 °C; wherein the weight ratio of the second shell polymer to the total of all other structures of the polymeric particle is from 0.5:1 to 3:1.The particle provides binding functionality and, when dry, opacity and energy savings. A method for providing a polymeric particle and a method for providing opacity to a dry coating are also provided.