Coloured Glass Flakes with Bulk Crystallization
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Solution Overview
Problem
Existing methods for producing glass flakes struggle to create consistently colored glass flakes at sub-micron thickness, as additives only affect the surface color and fail to maintain color and light scattering properties at thicknesses below 2 µm.
Innovation Solution
Incorporating nucleating agents like titanium dioxide and zinc oxide, along with sufficient amounts of color agents such as transition metals and rare earth metals, to promote crystallization and ensure color extends throughout the glass flake, rather than just on the surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional colouring agents (iron oxide, copper oxide, graphite) are added at high levels (>5% by weight) to produce coloured glass flake, then strong colour is achieved in thick sections (circa 10 μm and above), but the refractive index changes only slightly and the flakes below circa 2 μm thickness show merely a slight greying or change in brightness rather than true colour
Solution Approach 1:
The patent changes the chemical parameters by introducing rare earth metal oxides (neodymium oxide, praseodymium oxide, erbium oxide) as colouring agents instead of conventional iron oxide, copper oxide, or graphite. These rare earth oxides produce strong colour effects even at sub-micron thicknesses (below 2 μm) while maintaining appropriate refractive index properties, thereby achieving both strong colour intensity and colour consistency across different flake thicknesses.
Solution Approach 2:
The patent creates a composite glass formulation by combining conventional glass components (silica, soda ash, limestone, borax) with rare earth metal oxides as colouring agents and nucleating agents (titanium dioxide, zinc oxide). This composite material approach enables the glass flake to exhibit both structural integrity and intense, consistent colouration at sub-micron thicknesses, resolving the contradiction between colour intensity and colour consistency.
2Length of moving object
If glass flake thickness is reduced below 10 μm to achieve finer particles, then the light scattering properties and colour retention become problematic as the colour additives fail to maintain effective colouring at these reduced thicknesses
Solution Approach 1:
The patent changes the colouring agent parameters from conventional metals (iron, copper, graphite) to rare earth metal oxides (neodymium oxide, praseodymium oxide, erbium oxide). These rare earth oxides have unique optical properties that enable them to produce intense colour effects at extremely low concentrations and sub-micron thicknesses, thereby maintaining colour retention even when flake thickness is reduced below 10 μm.
Solution Approach 2:
The patent utilizes the inherent colour-changing properties of rare earth metal oxides when incorporated into glass matrices. These materials produce distinctive colours (violet for neodymium, green for praseodymium, pink for erbium) that are highly visible and retained even at sub-micron flake thicknesses, fundamentally changing the colour performance characteristics of thin glass flakes.
3Manufacturing precision
If the glass flake thickness is reduced to sub-micron levels (below 2 μm), then the flakes become finer and more uniform, but the conventional colouring agents fail to produce true colour and only create a slight greying or brightness change
Solution Approach 1:
The patent changes the colouring mechanism by using rare earth metal oxides instead of conventional additives. These rare earth oxides produce strong, true colours even at sub-micron thicknesses where conventional agents fail, thereby maintaining colour strength while achieving the desired thickness uniformity and fineness.
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 method achieves colored glass flakes with consistent color and light scattering properties at thicknesses below 10 µm, with specific formulations like the UVRB series producing golden/brown, blue, and other colors by controlling the nucleation and growth of crystal structures.
Implementation Method 1
the glass flake is at least partially crystalline and/or includes one or more clusters
Implementation Method 2
The film is fed between two plates, forming an annular venturi and is super-cooled with forced air
Implementation Method 3
The film is fed between two plates, forming an annular venturi and is super-cooled with forced air
Implementation Method 4
The film is broken up due to the high velocity air stream and the drag (frictional resistance) imparted by it
Implementation Method 5
The colour is not just on the surface of the material but extends throughout the flake
Data Source
AI summary
A glass flake having a thickness below 10μm and being coloured through the bulk of the material. The flake may be at least partially crystalline and/or include one or more clusters. A method of producing such flake comprises incorporating a nucleating agent and a colouring agent and heating the flakes to change the extent and/or nature of their crystallisation and/or clustering.