Alkyd Resin Pigment Paste Gelation Prevention
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Solution Overview
Problem
Pigment pastes containing iron oxide pigments tend to gel over time, leading to increased viscosity and the formation of hard lumps, which is undesirable in tinting systems, and current solutions like anti-oxidants are limited due to health and environmental concerns.
Innovation Solution
A solvent-borne pigment paste is developed using an alkyd resin produced from a non-drying oil or fatty acid with an iodine number of 115, esterified with trimellitic anhydride, ensuring at least 80% of the esterified residues have two free carboxylic groups, maintaining stability and preventing gelation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional alkyd resins are used in pigment pastes containing iron oxide pigments, then the pigment paste can be produced and used initially, but the viscosity increases over time leading to gelation and formation of hard lumps
Solution Approach 1:
The patent modifies the chemical parameters of the alkyd resin by esterifying with trimellitic anhydride to create a specific molecular structure with free carboxylic acid groups. This parameter change in the resin chemistry fundamentally alters the pigment paste's stability characteristics, preventing gelation without requiring antioxidants.
Solution Approach 2:
The invention creates a composite system by combining the modified alkyd resin (with esterified TMA residues) with iron oxide pigments. This composite material exhibits enhanced stability and resistance to gelation compared to conventional resin-pigment combinations, solving the stability problem while maintaining pigment functionality.
2Stability of the object's composition
If anti-oxidants are added to prevent gelation, then the stability of pigment paste is improved, but health and environmental concerns arise limiting their use
Solution Approach 1:
The patent extracts and eliminates the need for antioxidants from the pigment paste formulation. By modifying the alkyd resin structure through esterification with trimellitic anhydride, the invention removes the harmful component (antioxidants) while maintaining or improving the stability function through the resin's inherent chemical structure.
3Device complexity
If a limited number of base paints and pigment pastes are used in tinting systems, then stock control and logistics are rationalized, but the resin must be compatible with multiple pigments and base paints
Solution Approach 1:
The modified alkyd resin with esterified trimellitic anhydride residues possesses universal compatibility characteristics that allow it to work effectively with multiple different pigments and base paint formulations. This multi-functional resin reduces the need for specialized formulations for different pigment types, simplifying the tinting system's logistics while maintaining versatility.
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 solution provides a stable pigment paste that does not gel over time, maintaining constant viscosity and colloidal stability, suitable for use in tinting systems without the need for anti-oxidants, thus preventing the formation of hard lumps and ensuring compatibility with various pigments.
Implementation Method 1
esterification of the OH-functional alkyd with trimellitic anhydride (TMA)
Data Source
AI summary
The embodiments herein provide a solvent borne pigment paste comprising an alkyd, where the alkyd is obtainable by a process including the steps of a. producing an OH-functional alkyd from a non-drying oil or fatty acid, one or more polyols, and a first anhydride; where the non-drying oil or fatty acid has an iodine number ≥115; b. esterification of the OH-functional alkyd with trimellitic anhydride (TMA), where at least 80% of the esterified TMA residues has two free carboxylic groups. In some embodiments, at least 85%, at least 90%, or at least 98% of the esterified TMA residues has two free carboxylic groups.