Pigment Granules Core-Shell Structure Dust Control
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Solution Overview
Problem
Existing pigment granulation processes face challenges in achieving mechanical stability and good dispersibility, often resulting in dust pollution and requiring high amounts of additives that can affect the color strength and performance of building materials, plastics, and other applications.
Innovation Solution
The process involves creating pigment granules with a pressed or briquetted core and an outer layer applied by granulation, allowing for the use of a uniform core fraction that can be transported and processed, with the option to apply different pigments and auxiliaries in the outer layer for improved dispersibility and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pigment powders are milled to give primary particles to achieve optimum colour impression, then colour quality is improved, but dust pollution increases and metering becomes difficult
Solution Approach 1:
The pigment product is segmented into granulated form rather than fine powder, maintaining color quality while reducing dust. The granules contain milled pigment particles internally but present a granular external structure that prevents dust formation during handling and metering.
Solution Approach 2:
A coating layer is applied to the pigment granules that acts as a protective shell, preventing dust generation while allowing the internal milled pigment to maintain its color properties. The coating provides a surface that reduces dust adhesion and improves flow characteristics.
2Ease of operation
If granulation processes are applied to avoid dust and improve metering, then dust pollution is reduced and flow properties improve, but mechanical stability and dispersibility become conflicting requirements
Solution Approach 1:
The granule structure is segmented into core and coating layers, where the core provides mechanical stability for good flow and metering, while the coating layer facilitates dispersibility by reducing inter-particle adhesion. This segmentation allows both conflicting properties to coexist in different parts of the same granule.
Solution Approach 2:
The pigment granules are composite structures combining binder material in the core for mechanical stability and dispersant-containing coating for dispersibility. This composite approach allows the granules to simultaneously achieve good flow properties and easy dispersion in the application medium.
3Manufacturing precision
If larger amounts of dispersants are used to improve dispersibility, then dispersing properties are enhanced, but auxiliary/pigment cost ratio increases and colour strength decreases
Solution Approach 1:
The dispersant function is extracted and concentrated into the coating layer of the granules, rather than mixing dispersants throughout the entire pigment batch. This allows efficient use of dispersants only at the granule surface where they are most needed for initial wetting and dispersion, reducing overall dispersant requirements while maintaining good dispersibility.
Solution Approach 2:
Dispersants are applied locally to the coating layer rather than uniformly throughout the pigment mass. This localized application ensures dispersants are positioned where they most effectively reduce inter-particle forces during incorporation, maximizing their efficiency and minimizing the total amount needed, thus preserving color strength.
Data Source
AI summary
The present invention relates to pigment granules and to a process for the preparation thereof and their use.