Two-Step Ethoxylation of Polyethyleneimine for Viscosity Control
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Solution Overview
Problem
Existing processes for manufacturing ethoxylated polyethyleneimines used in laundry formulations often result in reduced viscosity, leading to consumer acceptability issues and the need for additional viscosity-boosting agents, while also producing by-products that negatively impact performance.
Innovation Solution
A two-step ethoxylation process where polyethyleneimine is initially reacted with less than one molar equivalent of ethylene oxide, followed by further reaction with ethylene oxide in the presence of a basic catalyst, to produce ethoxylated polyethyleneimines with higher molecular weights and improved viscosity without compromising cleaning performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyethyleneimine is reacted with ethylene oxide using standard processes (about one equivalent EO per NH), then hydroxyethyl groups are formed at reactive sites, but the viscosity of liquid laundry formulations is reduced
Solution Approach 1:
The ethoxylation process is divided into two distinct stages: (1) a first ethoxylation step without catalyst producing intermediate hydroxyethyl groups, and (2) a second ethoxylation step with basic catalyst completing the ethoxylation. This segmentation allows control over the degree of ethoxylation and prevents excessive chain scission that would reduce viscosity, while still achieving sufficient hydroxyethyl groups for cleaning performance.
Solution Approach 2:
The first ethoxylation step is performed preliminarily without catalyst to introduce some hydroxyethyl groups before the main catalyzed ethoxylation step. This preliminary action creates an intermediate product that maintains better viscosity characteristics while still providing some cleaning benefit, and then the second step completes the ethoxylation to achieve full cleaning performance.
2Reliability
If standard ethoxylation processes are used, then cleaning performance is achieved, but by-products are formed that negatively impact performance and cause malodor and dark color
Solution Approach 1:
The ethoxylation is segmented into two steps where the first step without catalyst produces fewer by-products compared to direct catalyzed ethoxylation. The intermediate product from step 1 has reduced malodor and color issues, and the second catalyzed step completes the reaction with minimal additional by-product formation due to the controlled progression.
Solution Approach 2:
The preliminary ethoxylation step without catalyst prepares the polyethyleneimine in a way that reduces subsequent by-product formation during the catalyzed step. This preliminary action modifies the polymer structure to be more resistant to side reactions that produce malodor and dark color, while still allowing the main ethoxylation to proceed effectively.
3Reliability
If higher molecular weight PEI is used, then bleach stability is improved, but the process complexity increases
Solution Approach 1:
The molecular weight of the starting polyethyleneimine is changed to higher ranges (2000-5000 g/mol or higher) to improve bleach stability. The two-step ethoxylation process is specifically designed to handle these higher molecular weight polymers effectively, maintaining their integrity while achieving sufficient ethoxylation for cleaning performance without excessive process complexity.
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 ethoxylated polyethyleneimines that enhance the viscosity of liquid laundry formulations while maintaining cleaning performance, offering a better compromise between rheological behavior and cleaning efficacy compared to standard processes.
Implementation Method 1
reacting at least one polyethyleneimine (PEI) with at least one ethylene oxide EO... the polyethyleneimine (PEI) is reacted with ethylene oxide EO... the product of step (1) is reacted with a further quantity of ethylene oxide EO
Implementation Method 2
in the presence of a basic catalyst C... in the presence of a basic catalyst
Data Source
AI summary
Described herein is a process for manufacturing ethoxylated polyethylene-imines. Also described herein are the ethoxylated polyethyleneimines and methods for using the ethoxylated polyethyleneimines.