Isoprene Latex Viscosity Control via Particle Distribution
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Solution Overview
Problem
Current synthetic isoprene polymer latexes exhibit high viscosity at high concentrations, limiting their concentration and increasing transportation costs, and existing methods struggle to maintain low viscosity even at high solid content levels.
Innovation Solution
A synthetic isoprene polymer latex is developed using solution polymerization with an alkyllithium catalyst, with a controlled particle diameter distribution and specific surfactant ratios, maintaining a Brookfield viscosity difference of 200 mPa·s or less between 56% and 66% solid content concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the solid content concentration of synthetic isoprene polymer latex is increased to reduce transportation costs, then transportation cost decreases, but viscosity rapidly increases making the latex difficult to transport
Solution Approach 1:
The patent changes the particle diameter distribution parameters of the latex, specifically controlling the mode diameter to be 0.5-2.0 μm and the median diameter to be 0.6-2.5 μm with a ratio of 0.8-1.5. This parameter optimization allows the latex to maintain low viscosity even at high solid content concentrations (60-70%), resolving the contradiction between transportation cost reduction and ease of handling
Solution Approach 2:
The patent creates a dynamic balance in the particle size distribution that adapts to concentration changes. By controlling the ratio between mode and median diameters to be within 0.8-1.5, the latex maintains optimal flow characteristics across different concentration levels, enabling both high concentration for cost-effective transport and low viscosity for ease of operation
2Ease of manufacture
If conventional synthetic isoprene polymer latex is used, then production is straightforward, but viscosity rapidly increases around 62% solid content concentration limiting further concentration increase
Solution Approach 1:
The patent optimizes the particle diameter parameters by controlling the mode diameter (0.5-2.0 μm) and median diameter (0.6-2.5 μm) with a specific ratio (0.8-1.5). This parameter control enables the latex to achieve higher solid content concentrations (60-70%) without the rapid viscosity increase that limits conventional latex at around 62% concentration
Solution Approach 2:
The patent performs preliminary control of particle diameter distribution during the polymerization process using chain transfer agents. By pre-establishing the optimal particle size distribution before concentration increase, the latex is prepared to maintain low viscosity at high concentrations, avoiding the need for later adjustments that would limit concentration
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 allows for the suppression of viscosity increase at high concentrations, enabling easier flow and cost-effective transportation of the latex, while maintaining the tensile strength and stability of the dip-formed articles.
Implementation Method 1
synthetic isoprene polymer obtained by solution polymerization using an alkyllithium polymerization catalyst
Implementation Method 2
a ratio between a mode diameter and a median diameter (mode diameter/median diameter) of a particle diameter of the latex is 0.8 or more
Data Source
AI summary
A dip-forming synthetic isoprene polymer latex contains a synthetic isoprene polymer which has been subjected to solution polymerization using an alkyllithium polymerization catalyst. A ratio between a mode diameter and a median diameter (mode diameter/median diameter) of a particle diameter of the latex is 0.8 or more. A Brookfield viscosity difference (V66−V56) between a Brookfield viscosity at a solid content concentration of 56% (V56) and a Brookfield viscosity at a solid content concentration of 66% (V66) is 200 mPa·s or less.