Styrene Butadiene Rubber Latex High Solids Process
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Solution Overview
Problem
Current methods for producing styrene butadiene rubber latex with high solids content are energy intensive and often result in coagulation, making them unsuitable for various applications such as adhesives and coatings.
Innovation Solution
A multi-step batch process involving the mixing of seeds, styrene, initiators, surfactants, and solvents, with controlled pH and temperature conditions, to create styrene butadiene rubber latex with increased solids content by adding portions of 1,3-butadiene in sequential reaction mixtures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If water is removed from low solids emulsion to obtain high solids content latex, then solids content is improved, but energy consumption increases and coagulation occurs
Solution Approach 1:
The patent performs preliminary action by conducting emulsion polymerization directly at high solids content (40-70 wt%) from the beginning, rather than starting with low solids content and subsequently removing water. This preliminary formulation of the polymerization system with high monomer concentration and controlled water content prevents the need for energy-intensive water removal processes while avoiding coagulation through proper initiator and surfactant selection.
Solution Approach 2:
The patent applies parameter changes by modifying the polymerization conditions including using higher monomer-to-water ratios, controlling pH levels, selecting specific initiators (potassium persulfate, ammonium persulfate), and adjusting temperature ranges (5-60°C) to enable direct formation of high solids content latex without subsequent water removal. These parameter changes allow the system to achieve high solids content while maintaining stability and preventing coagulation.
2Quantity of substance
If water is removed from low solids emulsion to obtain high solids content latex, then solids content is improved, but coagulation occurs
Solution Approach 1:
The patent performs preliminary action by conducting emulsion polymerization directly at high solids content (40-70 wt%) from the beginning, rather than starting with low solids content and subsequently removing water. This preliminary formulation of the polymerization system with high monomer concentration and controlled water content prevents the need for energy-intensive water removal processes while avoiding coagulation through proper initiator and surfactant selection.
Solution Approach 2:
The patent applies parameter changes by modifying the polymerization conditions including using higher monomer-to-water ratios, controlling pH levels, selecting specific initiators (potassium persulfate, ammonium persulfate), and adjusting temperature ranges (5-60°C) to enable direct formation of high solids content latex without subsequent water removal. These parameter changes allow the system to achieve high solids content while maintaining stability and preventing coagulation.
3Ease of manufacture
If conventional emulsion polymerization is used, then ease of manufacture is improved, but solids content remains low
Solution Approach 1:
The patent applies parameter changes by modifying the polymerization conditions including using higher monomer-to-water ratios, controlling pH levels, selecting specific initiators (potassium persulfate, ammonium persulfate), and adjusting temperature ranges (5-60°C) to enable direct formation of high solids content latex without subsequent water removal. These parameter changes allow the system to achieve high solids content while maintaining stability and preventing coagulation.
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 effectively produces styrene butadiene rubber latex with higher solids content, improved particle size, and Zeta potential, enhancing its suitability for adhesive compositions without the energy-intensive coagulation issues of conventional methods.
Implementation Method 1
The preparation of styrene butadiene rubber by emulsion polymerization has long been known
Implementation Method 2
one or more surfactants
Implementation Method 3
a base, where the base maintains a pH of the first emulsion from about 3.0 to about 12.0
Implementation Method 4
heating the first reaction mixture to a temperature above 40° C. for a first reaction time
Implementation Method 5
the first styrene butadiene rubber latex has an average Zeta potential from about −49.3 mV to about −78 mV
Data Source
AI summary
Disclosed herein are methods for making styrene butadiene rubber latex compositions with high solids content. In an embodiment, the method includes mixing a seed, a styrene, an initiator, a base, one or more surfactants, and a solvent; adding a first portion of 1,3-butadiene to make a first reaction mixture; heating the first reaction mixture to make a first styrene butadiene rubber latex, where the first styrene butadiene rubber latex has an average Zeta potential from about −49.3 mV to about −78 mV; mixing the first styrene butadiene rubber latex, a styrene, a base, an initiator, one or more surfactants, and a solvent; adding a second portion of 1,3-butadiene to make a second reaction mixture; and heating the second reaction mixture to make a second styrene butadiene rubber latex, where the second styrene butadiene rubber latex has an average Zeta potential from about −41 mV to about −64 mV.