Solid Pigment Preparations with Antioxidants for Stable Drying
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Solution Overview
Problem
Solid pigment preparations containing surface-active additives with alkylene oxide groups tend to decompose when dried with inorganic pigments, leading to safety risks and process instability, especially at temperatures above 80°C.
Innovation Solution
The development of pigment preparations that include a coloring component, a water-soluble surface-active additive, and an antioxidant, where the pigment is subjected to wet comminution in an aqueous suspension with the antioxidant and additive, followed by drying, allowing for stable production and efficient incorporation into high molecular weight materials and plastics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If surface-active additives containing alkylene oxide groups are used in solid pigment preparations, then dispersibility and stir-in behavior are improved, but decomposition occurs during drying at temperatures above 80°C leading to safety risks
Solution Approach 1:
The patent introduces antioxidants as intermediary substances that mediate between the surface-active additives and the drying process. These antioxidants prevent the decomposition of alkylene oxide groups during drying, allowing the beneficial dispersibility properties to be maintained while eliminating the safety risks associated with thermal decomposition above 80°C
Solution Approach 2:
The patent modifies the chemical composition parameters of the pigment preparation by adding specific antioxidants (0.1 to 5% by weight). This parameter change stabilizes the surface-active additives during the drying process, enabling safe processing at temperatures above 80°C while preserving the dispersibility and stir-in behavior characteristics
2Productivity
If drying temperature is increased above 80°C, then production efficiency is improved, but self-ignition risk increases due to decomposition of surface-active additives
Solution Approach 1:
The patent applies beforehand cushioning by incorporating antioxidants into the pigment preparation before the drying process. This pre-protection mechanism cushions against the harmful thermal effects during drying, enabling safe operation at higher temperatures (above 80°C) that improve production efficiency without triggering self-ignition risks
3Reliability
If wet comminution is performed in aqueous suspension with antioxidants and additives, then process stability is improved, but additional process steps are required
Solution Approach 1:
The patent merges multiple functions into a single wet comminution process step. The aqueous suspension simultaneously serves as the medium for particle size reduction, the source of antioxidants for stabilizing surface-active additives, and the vehicle for uniform distribution of all components. This consolidation achieves process stability without significantly increasing overall 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 ensures stable drying temperatures above 70°C without self-ignition risks, maintaining the dispersibility and coloristic properties of the pigments, and enables efficient coloring of organic and inorganic materials with improved storage stability and handling characteristics.
Implementation Method 1
surface-active additives containing alkylene oxide groups tend to decompose, especially in the presence of inorganic pigments based on iron oxides, even at drying temperatures > 80°C
Implementation Method 2
subjecting the pigment (A1) to wet comminution in an aqueous suspension containing the antioxidant (C) and at least part of the additive (B)
Implementation Method 3
the suspension is then dried, optionally after addition of the remaining amount of additive (B)
Data Source
AI summary
The invention relates to solid pigment preparations containing the essential components: (A) 45-90 % by weight at least one type of chromophore component, (A1) 5-100 % by weight at least one type of pigment and (A2) 0-95 % by weight at least one type of inherent colourless filler, (B) 5-50 % by weight at least one type of water-soluble surface-active additive, an additive group containing oxide-alkylene groups (B1) and alkylene oxide-free groups (B2), wherein the proportion of the oxide-alkylene groups (B1) containing additives in pigment preparations is equal to or greater than 5 % by weight and (C) from 0.1 to 5 % by weight an antioxidant. The production and use of said pigment preparations for dyeing high molecular weight organic and inorganic materials and plastic materials are also disclosed.