Alkaline-Swellable Emulsion Polymers with Gradient Crosslinking
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Solution Overview
Problem
There is a need for additional alkaline-swellable polymers that can function as effective rheology modifiers, which are not currently available in existing technologies.
Innovation Solution
A method for producing emulsion polymer particles with a specific composition, comprising 25 to 45 wt% polymerized residues of C3-C6 carboxylic acid monomers and 0.1 to 3 wt% polymerized residues of crosslinkers, where the crosslinker concentration increases from the particle centers to the surfaces, using a power feed process in a polymerization reactor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional emulsion polymerization is used to produce alkaline-swellable polymers, then polymer production is achieved, but the polymers lack effective rheology modification properties
Solution Approach 1:
The patent applies local quality by creating a non-uniform distribution of crosslinker within the polymer particles. The crosslinker concentration increases from the particle center to the surface, with the surface region containing 0.5-3 wt% crosslinker and the core containing 0.1-1 wt% crosslinker. This gradient structure provides enhanced rheology modification effectiveness by concentrating crosslinking functionality at the particle surface where it can interact more effectively with the surrounding medium.
Solution Approach 2:
The patent employs preliminary action by pre-mixing the crosslinker with a portion of the monomer mixture before introducing it to the polymerization reactor. The crosslinker is incorporated during the polymerization process itself, allowing it to become uniformly distributed and properly positioned within the forming particles before crosslinking reactions occur. This ensures optimal crosslinker placement for rheology modification.
2Adaptability or versatility
If power feed process is used to produce polymers, then polymer production is achieved, but additional alkaline-swellable polymers with specific properties are not available
Solution Approach 1:
The patent achieves universality by developing a modified power feed polymerization process that can produce multiple types of alkaline-swellable polymers with different compositions and properties. By adjusting the monomer composition (C3-C6 carboxylic acid monomers, C1-C12 alkyl (meth)acrylates, and other comonomers) and crosslinker content, the same process can generate polymers tailored for various rheology modification applications, making the process multi-functional and adaptable.
Solution Approach 2:
The patent applies dynamics by implementing a dynamic power feed process where monomer and crosslinker mixtures are continuously added to the reactor during polymerization. The feed rates and compositions can be adjusted during the process to control particle formation, size distribution, and crosslinker placement. This dynamic approach enables flexible production of polymers with specific properties for different applications.
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 resulting polymer particles provide enhanced clarity and suspension properties in aqueous formulations, improving their performance as rheology modifiers in various applications such as body washes, shampoos, and hard surface cleaners, while maintaining low turbidity and viscosity control.
Implementation Method 1
alkaline-swellable emulsion polymers
Implementation Method 2
emulsion polymer particles comprising from 25 to 45 wt% polymerized residues of at least one C 3 -C 6 carboxylic acid monomer and from 0.1 to 3 wt% polymerized residues of at least one crosslinker
Data Source
AI summary
Emulsion polymer particles comprising from 25 to 45 wt% polymerized residues of at least one C3-C6 carboxylic acid monomer and from 0.1 to 3 wt% polymerized residues of at least one crosslinker, wherein percentage of crosslinker increases continuously from particle centers to particle surfaces.