Modified Polyacrylate Defoamer for Aqueous Coatings
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Solution Overview
Problem
Conventional defoamers often exhibit poor defoaming abilities, are short-lived, and can interfere with the properties of aqueous compositions, such as paint, leading to issues like craters and fish-eyes on the surface coat, and may not be compatible with all components, affecting the rheology or causing precipitate formation.
Innovation Solution
A defoamer composition comprising a hydrophobic liquid and a modified polyacrylate polymer, where the polyacrylate polymer is obtained by polymerizing acrylate monomers and then modified through trans-esterification with polyalkylether alcohols and optionally unsubstituted C8-C36 alcohols, providing effective defoaming activity while maintaining compatibility with aqueous compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional defoamers are used to reduce foam in aqueous compositions, then defoaming ability is improved, but compatibility with aqueous composition components deteriorates, leading to rheology changes or precipitate formation
Solution Approach 1:
The invention uses a composite defoamer system comprising modified polyacrylate polymer (with transesterified polyalkylether alcohol and C8-C36 alcohol groups) combined with hydrophobic liquid. This composite structure integrates multiple functional components that work synergistically: the modified polyacrylate provides defoaming activity and compatibility, while the hydrophobic liquid enhances defoaming efficiency. The composite material approach resolves the contradiction by combining substances with complementary properties to achieve both effective defoaming and stability in aqueous compositions.
Solution Approach 2:
The invention modifies the polyacrylate polymer through transesterification reactions that change its chemical parameters - specifically introducing polyalkylether alcohol and C8-C36 alcohol groups onto the polymer backbone. These parameter changes in the defoamer's molecular structure enhance its compatibility with aqueous composition components while maintaining defoaming ability. The modified polymer exhibits altered solubility, surface activity, and interaction properties that prevent rheology changes and precipitate formation.
2Reliability
If effective amount of defoamer composition is added to aqueous composition, then foam reduction is improved, but desirable properties of aqueous composition deteriorate, such as glossy finish
Solution Approach 1:
The modified polyacrylate polymer exhibits concentration-dependent behavior with optimal performance at low dosages (0.01-5.0 wt%). At these low concentrations, the defoamer effectively reduces foam without reaching threshold levels that would interfere with the aqueous composition's glossy finish. The transesterified structure ensures that even at effective defoaming concentrations, the defoamer does not disrupt the coating's aesthetic properties.
Solution Approach 2:
The hydrophobic liquid component acts as an intermediary that enhances defoaming efficiency, allowing the modified polyacrylate polymer to achieve effective foam control at lower concentrations. This intermediary substance amplifies the defoaming action of the polymer, reducing the need for high dosages that would otherwise compromise surface finish quality.
3Reliability
If defoamers comprising waxes and paraffin oils are used, then defoaming ability is improved, but scrub resistance of surface coats deteriorates
Solution Approach 1:
The invention replaces traditional wax and paraffin oil-based defoamers with a chemically modified polyacrylate polymer system. The transesterification introduces polar functional groups (polyalkylether alcohol and C8-C36 alcohol) that change the defoamer's interaction with the aqueous composition and surface coat. This parameter change in chemical structure eliminates the harmful effects of waxes and paraffins while maintaining effective defoaming capability.
Solution Approach 2:
The modified polyacrylate polymer serves as a short-lived defoaming agent that performs its function during mixing and application, then does not persist to interfere with the final coating properties. Unlike waxes and paraffins that can remain in the coating and affect scrub resistance, the modified polymer's defoaming action is effective during the process but does not compromise the durability and resistance of the cured coating.
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 defoamer composition effectively reduces or prevents foam in aqueous compositions without altering their desirable properties, ensuring a stable and defect-free surface finish, even at low concentrations.
Implementation Method 1
modifying the at least one polyacrylate polymer obtained in step (i) by trans-esterification with at least one polyalkylether alcohol (c2) and optionally at least one unsubstituted C 8 -C 36 alcohol (c1)
Implementation Method 2
The defoamer composition effectively reduces or prevents foam in aqueous compositions
Implementation Method 3
Defoamers or defoamer compositions are commonly used to abate foaming in aqueous compositions
Data Source
AI summary
The invention relates to a defoamer composition. The invention also relates to a method for reducing or preventing foam in an aqueous composition. The defoamer composition of the invention comprises at least one hydrophobic liquid; and at least one modified polyacrylate polymer. The modified polyacrylate polymer is obtainable by a process comprising 1. polymerizing at least one acrylate monomer selected from substituted or unsubstituted C1-C22 alkyl acrylates, substituted or unsubstituted C4-C22 cycloalkyl acrylates, substituted or unsubstituted C1-C22 acrylamides, esters of acrylic acid with polyalkylether alcohol, or combinations of two or more thereof, to obtain at least one polyacrylate polymer; and 2. modifying the at least one polyacrylate polymer obtained in step (i) by transesterification with at least one alcohol selected from (c1) at least one unsubstituted C8-C36 alcohol, (c2) at least one polyalkylether alcohol, or combinations of two or more thereof.