Core-shell wax composites for scratch resistance
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Solution Overview
Problem
Conventional filler particles in coating and dispersion systems, such as paints and plastics, improve scratch resistance but often lead to increased brittleness and clouding, requiring high filler contents that are costly and difficult to stabilize.
Innovation Solution
Inorganic-organic composite particles with a core/shell structure, where the core is made of wax with functional groups that form physical or chemical bonds with the inorganic shell, providing enhanced mechanical properties and stability without significant clouding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional inorganic filler particles are incorporated to improve scratch resistance, then wear resistance is improved, but brittleness increases and transparency decreases
Solution Approach 1:
The patent applies composite materials by combining organic wax particles with inorganic shell coating to create hybrid filler particles. The core consists of natural or synthetic wax particles, while the shell comprises inorganic materials such as silica, aluminum oxide, or titanium dioxide. This composite structure allows the particle to exhibit both the flexibility and transparency of organic wax and the hardness and wear resistance of inorganic materials, thereby improving scratch resistance without increasing brittleness or causing clouding.
Solution Approach 2:
The patent applies local quality by creating a core/shell structure where different regions of the particle have different properties. The inner core provides flexibility and transparency, while the outer shell provides hardness and wear resistance. This spatial differentiation of properties allows the single particle to simultaneously address multiple requirements: maintaining system flexibility through the soft core while providing scratch resistance through the hard shell surface.
2Strength
If high filler content is used to achieve desired wear resistance effects, then mechanical properties are improved, but dispersion system stability becomes difficult to maintain and costs increase
Solution Approach 1:
The patent applies parameter changes by modifying the physical and chemical parameters of the filler particles. The core/shell structure changes the density, surface area, and surface chemistry parameters of the filler. The organic-organic interface between core and shell creates optimal surface properties that enhance compatibility with dispersion media, allowing stable dispersions at lower filler concentrations while achieving the desired wear resistance.
Solution Approach 2:
The composite structure improves dispersion stability through the amphiphilic nature of the particles. The organic wax core provides compatibility with organic binders and dispersants, while the inorganic shell provides surface functionality for stabilization. This dual-character structure allows the particles to remain stably dispersed at lower concentrations, reducing both cost and stability issues associated with high filler loads.
3Strength
If conventional filler particles are incorporated to improve abrasion resistance, then mechanical durability is improved, but transparency and gloss are reduced
Solution Approach 1:
The patent applies local quality by concentrating the light-scattering inorganic material in a thin outer shell rather than distributing it throughout the entire particle volume. The larger inner core consists of transparent or translucent organic wax material. This spatial arrangement allows the particle to provide abrasion resistance through the hard shell while maintaining transparency and gloss through the transparent core, effectively decoupling the optical and mechanical functions.
Solution Approach 2:
The composite structure combines the transparency of organic wax with the hardness of inorganic materials in a way that optimizes optical properties. The organic core maintains light transmission and surface gloss, while the inorganic shell provides the necessary abrasion resistance. This composite approach allows achieving wear protection without the severe transparency loss that occurs with conventional inorganic fillers.
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 composite particles significantly improve wear resistance and abrasion resistance with lower filler content, reducing brittleness and clouding, and can be incorporated homogeneously into systems, offering cost savings and improved performance.
Implementation Method 1
The incorporated additional components are intended, among other things, to provide the wax with improved flowability during the extrusion process
Implementation Method 2
the wax containing functional groups which are able to interact with the inorganic material of the shell by forming physical and/or chemical bonds
Implementation Method 3
EP 1 182 233 B1 relates to a process for coating silicas with waxes
Implementation Method 4
The shell is applied to the core in an at least essentially uniform layer thickness, in particular as a precipitate
Implementation Method 5
dispersions which contain these composite particles in a carrier or dispersing medium
Data Source
AI summary
The invention relates to inorganic-organic composite particles having a core/shell structure, wherein the composite particles comprise an organically based core having at least one wax, and an inorganically based shell surrounding said core, and to a method for the production thereof and to the use thereof.