Transparent Ceramic Coating Resolves White Cast and Adhesion
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Solution Overview
Problem
Ceramic moldings with photocatalytically active coatings have limited air-purifying properties and often exhibit a 'white cast' due to light scattering, which affects their appearance and functionality.
Innovation Solution
A ceramic molding with a capillary structure and a surface coating comprising peptized, non-photocatalytically active particles, photocatalytically active particles surrounded by a peptized layer, and a metatitanic acid layer, which provides both self-cleaning and air-purifying properties while maintaining transparency and excellent adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If photocatalytically active particles are applied to ceramic moldings, then self-cleaning properties are improved, but air-purifying properties remain limited and a white cast appears
Solution Approach 1:
The patent applies a composite coating system consisting of multiple layers: a base layer with photocatalytically active TiO2 particles for self-cleaning, an intermediate layer with peptized particles for adhesion enhancement, and a top metatitanic acid layer for transparency and air-purifying functionality. This multi-layer composite structure resolves the contradiction by combining materials with complementary properties.
Solution Approach 2:
Different layers of the coating are assigned different functional properties: the base layer provides photocatalytic activity, the intermediate layer provides adhesion and dispersion, and the top layer provides transparency and air-purifying capability. This local differentiation of quality allows each layer to optimize its specific function while contributing to overall performance.
2Reliability
If a photocatalytically active coating is applied to ceramic moldings, then self-cleaning effect is achieved, but transparency of the surface coating deteriorates
Solution Approach 1:
The patent transitions from a single-layer coating to a multi-layer vertical structure, adding the dimension of layering to solve the transparency problem. The metatitanic acid top layer acts as a transparent protective barrier that allows light transmission while the underlying photocatalytic layer maintains self-cleaning functionality through UV light interaction.
Solution Approach 2:
The metatitanic acid layer serves as an intermediary between the photocatalytic TiO2 particles and the external environment. It mediates by providing a transparent interface that allows light to reach the photocatalytic layer while protecting it and enabling air-purifying functions without compromising transparency.
3Object-generated harmful factors
If photocatalyst particles are applied to ceramic surface, then air-purifying properties are improved, but adhesion of the coating deteriorates
Solution Approach 1:
The patent applies peptized particles in the intermediate layer before applying the final metatitanic acid layer. The peptization process pre-treats the particles with dispersants that enhance surface activity and adhesion properties, preparing the surface for subsequent layer application and ensuring strong bonding between layers.
Solution Approach 2:
The patent changes the surface chemical parameters of the particles through peptization, modifying their surface charge and reactivity. This parameter change from untreated to peptized particles significantly improves adhesion between the coating layers and the ceramic substrate while maintaining air-purifying properties.
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 achieves significant air-purifying capabilities, self-cleaning effects, and maintains a transparent, matte appearance with enhanced adhesion to the ceramic surface, effectively addressing the limitations of existing technologies.
Implementation Method 1
a photocatalytically active, air-purifying and preferably transparent coating
Implementation Method 2
Peptized particles are therefore preferably understood to mean particles on the surface of which an electrostatically charged or electrostatically chargeable dispersant is attached. Through this attachment, which is also referred to as peptization, the secondary aggregates created during the production of the particles are converted into primary aggregates that can form stable colloidal dispersions.
Implementation Method 3
a photocatalytically active, air-purifying and preferably transparent coating
Data Source
Figure 1a~1c
AI summary
The ceramic molded body e.g. roofing tile, brick, clinker and/or facade panel, made of oxide-ceramic base material with capillary structure, comprises a transparent air-cleaning surface coating, which comprises peptized photocatalytic-active particles (1) and/or photocatalytic-active particles, which are surrounded by a layer from peptized particles. The peptized photocatalytic active particles and/or photocatalytic active particles are formed as primary aggregates. The photocatalytic active particles comprise a band-gap of 3.0-3.5 eV and are producible by a sulfate pulping method. The ceramic molded body e.g. roofing tile, brick, clinker and/or facade panel, made of oxide-ceramic base material with capillary structure, comprises a transparent air-cleaning surface coating, which comprises peptized photocatalytic-active particles (1) and/or photocatalytic-active particles, which are surrounded by a layer from peptized particles. The peptized photocatalytic active particles and/or photocatalytic active particles are formed as primary aggregates. The photocatalytic active particles comprise a band-gap of 3.0-3.5 eV and are producible by a sulfate pulping method. The surface coating further comprises peptized non-photocatalytic active particles, non-photocatalytic active particles (3), which are surrounded by a layer from peptized particles and/or non-peptized non-photocatalytic active particles. The photocatalytic active particles and the non-photocatalytic active particles measured without peptization comprise average particle size of 2-20 nm and 10-15 nm respectively. A peptide layer (2) having a thickness of 1-2 nm is arranged on the non photocatalytic active peptized particles and/or on the photo-catalytic-active peptized particles. The surface coating comprises titanium dioxide-particle, which is surrounded by a completely or partially closed layer from peptized aluminum oxide-particle and/or peptized titanium dioxide-particle. Metatitanic acid-containing layer (4) is arranged between the titanium dioxide-particle and the closed layer and/or between the titanium dioxide-particle and the peptide layer. The titanium dioxide-particle, the metatitanic acid-containing layer and the closed layer form the primary aggregate with an average particle size of 35-45 nm. The surface coating has an average particle size of 2-5 nm and a thickness of 20-200 nm, and comprises an organic or inorganic bonding agent. The weight ratio of bonding agent to the photocatalytic-active particle is 1:1 to 1:0.6. An engobe or a glaze is arranged between the oxide-ceramic base material with capillary structure and the surface coating. The mass ratio of the photocatalytic particle to the non-photocatalytic-active particles is 3:6 to 4:6. The peptide- and/or metatitanic acid-containing layer are removed by heating at 300-600[deg] C. An independent claim is included for method for the production of a rough-ceramic molded article e.g. a roofing tile, brick, clinker and/or facade panel from oxide-ceramic base material.