Voided Latex Particles via Swelling-Polymerization Merge
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Solution Overview
Problem
Existing processes for producing hollow latex particles face challenges in timing the swelling and shell polymerization steps, leading to undesirable product performance and the use of volatile emissions like ammonia.
Innovation Solution
A multi-stage emulsion polymerization process where a swelling agent is added with less than 0.5% monomer, allowing substantial swelling to occur during the polymerization of the outer shell, avoiding timing issues and using environmentally friendly agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a separate swelling step is performed after polymerization of core and shell layers, then hollow latex particles can be formed, but the process timing becomes difficult to control on commercial plant scale resulting in compromised particle geometry and morphology
Solution Approach 1:
The patent combines the swelling step with the shell polymerization step by adding the swelling agent at the beginning of the shell polymerization process. This merging of operations eliminates the need for separate timing control of swelling and polymerization, allowing both processes to occur simultaneously in a single reaction step, thereby resolving the timing control difficulty while maintaining particle geometry precision
Solution Approach 2:
The swelling agent is added before the shell polymerization begins, allowing the swelling process to start in advance and proceed concurrently with polymerization. This preliminary action ensures that the core swells to the desired extent during the polymerization process itself, eliminating the need for separate timing coordination between these two steps
2Reliability
If traditional hollow latex processes are used, then opacifier function is achieved, but volatile emissions such as ammonia are released causing environmental concerns
Solution Approach 1:
The patent changes the chemical parameter of the swelling agent from traditional ammonia to alternative compounds such as organic carbonates, carboxylic acid esters, or amides. This parameter change maintains the swelling function necessary for hollow particle formation and opacifier performance while eliminating or reducing harmful volatile emissions, thus resolving the environmental concern
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 process produces voided latex particles with desirable performance characteristics, such as non-film-forming properties and improved opacity, while minimizing the use of volatile emissions and ensuring consistent particle morphology.
Implementation Method 1
the core comprises a hydrophilic component; the core and the at least one intermediate shell are contacted with swelling agent
Implementation Method 2
polymerizing an outer shell after said contacting with swelling agent wherein: the outer shell comprises a polymer
Data Source
AI summary
A process for forming voided latex particles is improved by combining swelling and polymerization of an outer shell into a single step. The process includes contacting multi-stage emulsion polymer particles comprising a core, at least one intermediate shell, with a swelling agent, and polymerizing an outer shell after said contacting with swelling agent wherein the core and the at least one intermediate shell are contacted with swelling agent in the presence of less than 0.5% monomer based on the weight of the multi-stage emulsion polymer particles, and substantially all of the swelling occurs during polymerization of the outer shell.