Hydroxyalkyl Acrylate Dispersant Polymer for Dishwashing Films
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Solution Overview
Problem
Current phosphate-free automatic dishwashing compositions suffer from unsatisfactory spotting and filming performance, with existing polymers failing to prevent certain film deposits on glassware and stainless steel, and requiring strong chelants or specialized surfactants, which increase costs.
Innovation Solution
A dispersant polymer comprising >60 to <90 wt % of structural units of formula I and >10 to <40 wt % of structural units of formula II, along with a builder and nonionic surfactant, provides improved spotting and filming performance in phosphate-free formulations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If phosphate-free automatic dishwashing compositions use conventional dispersant polymers (polyacrylic acid or copolymers with sulfonated monomers), then they can sequester calcium and magnesium from hard water, but they fail to prevent certain film deposits on glassware and stainless steel, and require strong chelants or specialized surfactants that increase costs
Solution Approach 1:
The patent changes the chemical parameters of the dispersant polymer by specifying a copolymer with >60 to <90 wt% acrylic acid units and >10 to <40 wt% hydroxyalkyl acrylate units, with particular emphasis on hydroxypropyl acrylate. This specific compositional parameter range provides superior film prevention performance without requiring additional costly additives.
Solution Approach 2:
The invention creates a composite dispersant system by combining acrylic acid units with hydroxyalkyl acrylate units in a specific ratio within a single copolymer chain. This composite structure at the molecular level provides both water softening capability and film deposit prevention, eliminating the need for separate chelants or specialized surfactants.
2Reliability
If copolymers of acrylic acid with sulfonated monomers are used, then silicate and phosphonate scale prevention is excellent, but carbonate scale prevention is not particularly effective, and spotting performance deteriorates
Solution Approach 1:
The patent changes the monomer composition parameters by replacing sulfonated monomers with hydroxyalkyl acrylate units (particularly hydroxypropyl acrylate) in the copolymer structure. This parameter change maintains scale prevention effectiveness while significantly improving spotting performance on glassware and stainless steel surfaces.
3Quantity of substance
If polyacrylic acid polymers are used to combat deposit formation, then they provide basic dispersancy, but they fail to prevent certain film deposits on glassware presenting as transparent blue to blue/white films and brown films on stainless steel
Solution Approach 1:
The invention enhances basic polyacrylic acid dispersancy by incorporating hydroxyalkyl acrylate units into the polymer chain to create a copolymer. This composite structure adds film-preventing functionality to the dispersant system, specifically preventing transparent blue/white films on glassware and brown films on stainless steel while maintaining water softening capability.
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 dispersant polymer effectively prevents film deposits on various surfaces, including glassware and stainless steel, while maintaining cost-effectiveness without the need for strong chelants or specialized surfactants.
Implementation Method 1
a dispersant polymer comprising: (a) >60 to <90 wt % of structural units of formula I... and (b) >10 to <40 wt % of structural units of formula II... The dispersant polymer effectively prevents film deposits on various surfaces, including glassware and stainless steel
Implementation Method 2
The hydroxyalkyl groups (R2 = C1-6 hydroxyalkyl) in the copolymer structure provide steric bulk that prevents close approach of deposit-forming species to the surface, while the carboxylate groups provide electrostatic repulsion and binding to metal ions
Data Source
AI summary
An automatic dishwashing composition is provided including a builder; a nonionic surfactant; and a dispersant polymer comprising: (a) >60 to <90 wt %, based on weight of the dispersant polymer, of structural units of formula Iwherein each R1 is independently selected from a hydrogen and a —CH3 group; and (b) >10 to <40 wt %, based on weight of the dispersant polymer, of structural units of formula IIwherein each R2 is independently selected from the group consisting of a C1-6 hydroxyalkyl group and a C1-6 alkoxy group; and wherein each R3 is independently selected from a hydrogen and a methyl group.