Acrylic Polymer Beads Low Residual Monomer Suspension
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Solution Overview
Problem
Acrylic polymer beads used in hair care products face limitations due to high residual monomer content, which leads to toxicological issues, dustiness, and poor processing characteristics, limiting their application in personal care products.
Innovation Solution
A process involving suspension polymerization of a monomer composition comprising methacrylic acid, n-butyl methacrylate, ethyl acrylate, and ethyl methacrylate is used to produce acrylic polymer beads with low residual monomer content, high glass transition temperature, and improved handling properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If suspension polymerization is used to produce acrylic polymer beads, then particle size and handling properties are improved, but residual monomer content increases leading to toxicological issues
Solution Approach 1:
The patent modifies the chemical composition parameters by incorporating specific functional monomers (carboxylic acid groups) and controlling the ratio of hydrophobic to hydrophilic monomers. This parameter change enables the polymer beads to achieve both good handling properties and low residual monomer content through enhanced water solubility and reduced monomer entrapment
Solution Approach 2:
The patent creates a composite polymer structure by copolymerizing multiple monomers including methacrylic acid, n-butyl methacrylate, ethyl acrylate, and ethyl methacrylate. This composite approach allows the beads to combine the benefits of suspension polymerization (good handling) while minimizing residual monomer through the synergistic effects of different monomer functionalities
2Object-affected harmful factors
If emulsion polymerization is used to reduce residual monomer content, then toxicological issues are reduced, but particle size becomes too small causing dusting problems
Solution Approach 1:
The patent employs a nested structure where micron-sized polymer beads are formed within suspension polymerization, but the internal structure incorporates emulsion-like characteristics through the use of water-soluble functional groups. This nested approach allows the beads to maintain large external size (reducing dusting) while having internal structures that minimize monomer entrapment (reducing residual monomer)
Solution Approach 2:
The patent changes the critical parameter of particle size from sub-micron (emulsion) to micron range (suspension) while simultaneously modifying the chemical composition to include carboxylic acid functional groups. This dual parameter change allows achieving low residual monomer content typically associated with emulsion polymerization while maintaining the larger particle size benefits of suspension polymerization
3Stability of the object's composition
If polymer beads are produced with high glass transition temperature to prevent sticking, then processing stability is improved, but formulation complexity increases
Solution Approach 1:
The patent achieves high glass transition temperature (80-120°C) by controlling the monomer composition ratios, particularly the balance between hydrophobic monomers (n-butyl methacrylate, ethyl methacrylate) and hydrophilic monomers (methacrylic acid, ethyl acrylate). This parameter optimization provides processing stability without requiring additional formulation complexity or separating agents
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 process results in acrylic polymer beads with residual monomer content below 100 ppm, preventing sticking and dustiness, and enabling their use in hair care products with enhanced solubility and styling properties, suitable for aerosol and pump spray formulations.
Implementation Method 1
subjecting a monomer composition consisting of a mixture of methacrylic acid (MAA), n-butyl methacrylate (BMA), ethylacrylate (EA) and ethyl methacrylate (EMA) to suspension polymerization
Data Source
AI summary
The present invention relates to acrylic polymer beads having very low residual monomer content as well as to their use in hair care preparations in particular as styling agent.