Ceramic Tiles & Sanitaryware

Ceramic tiles and sanitaryware are widely used in environments characterized by high humidity, frequent contact, and organic residue, such as bathrooms and kitchens. Under these conditions, microbial growth-including bacteria and mold-is difficult to avoid.

To address this, antibacterial functionality is increasingly integrated into ceramic materials. However, unlike simple surface coatings, effective ceramic antibacterial systems must withstand high-temperature firing, chemical exposure, and long-term wear, while maintaining the original appearance and mechanical properties of the product.

Ceramic processing involves multiple constraints that limit material selection:

• High firing temperatures (typically hundreds of °C)
• Complex glaze chemistry
• Strict requirements on surface appearance (color, gloss, transparency)

An antibacterial additive used in ceramics must therefore:

• Remain stable during firing
• Disperse uniformly in glaze systems
• Avoid discoloration or defects
• Maintain functionality after long-term use

This makes ceramic antibacterial applications more demanding than those in plastics or coatings.

A commonly used system in ceramic antibacterial applications is nano zinc oxide (ZnO).

Typical material characteristics include:

• Active component: nano-scale zinc oxide
• Form: powder or aqueous slurry
• Composition example:

1. 10–25% nano ZnO
2. 75–89% deionized water
3. Small amount of dispersant

The nano-scale particle size is critical, as it enables:

• Uniform dispersion in glaze or coating systems
• Consistent surface coverage
• Stable antibacterial performance

Two main integration routes are commonly used in tile and sanitaryware production:

Route A: Incorporation into Glaze (Firing Process)

In this method:

1. Antibacterial powder or slurry is mixed into the glaze
2. The mixture is dispersed (e.g., via ball milling)
3. The glaze is applied to the ceramic body
4. The product is fired and polished

Key characteristics:

• Antibacterial function becomes part of the glaze layer
• Suitable for long-term, high-durability applications
• Reported antibacterial rates can exceed 99% against common bacteria
• Performance can remain stable even after extensive surface wear

Route B: Post-Treatment via Polishing Medium

An alternative approach is surface-stage application:

1. Add antibacterial slurry into polishing wax water (typically 0.5–0.8%)
2. Mix uniformly
3. Spray onto ceramic surface
4. Dry to form functional layer

Key characteristics:

• Does not require changes to core ceramic formulation
• Easier to implement in existing production lines
• Provides high antibacterial performance after drying

A critical requirement for ceramic additives is thermal stability.

Key observations:

• Nano ZnO systems can withstand high-temperature firing without decomposition
• No significant color change or visual defects after firing
• Stable under acidic and alkaline conditions
• Compatible with ceramic glaze systems

These properties ensure that antibacterial performance is preserved throughout the manufacturing process.

From a practical perspective, performance should be evaluated based on measurable surface outcomes, rather than general claims.

Key indicators include:

• Antibacterial rate (>99% against common bacteria such as E. coli and Staphylococcus aureus)
• Mold resistance (e.g., mildew resistance Grade 0)
• Durability (retention of performance after repeated cleaning or abrasion)
• Chemical resistance (acids, alkalis, cleaning agents)
• Stability of appearance (no yellowing or discoloration)

These metrics are especially relevant for high-use surfaces such as bathroom tiles and sanitary fixtures.

Nano antibacterial ceramic materials are most suitable in environments where the following conditions overlap:

• Persistent moisture
• Frequent human contact
• Long service life requirements

Typical applications include:

• Floor and wall tiles
• Toilets and wash basins
• Bathtubs
• Daily-use ceramic products
• Medical or hygiene-sensitive ceramic components

Recommended addition levels vary depending on system design:

• Typical range: ~0.5% – 1% for most antibacterial systems
• Higher loadings (e.g., ~3%) may be used depending on formulation type

Because ceramic systems are highly process-sensitive, a practical approach is:

1. Start with small-scale trials
2. Verify dispersion in glaze or polishing medium
3. Evaluate surface appearance and antibacterial performance
4. Test durability under real-use conditions

This iterative approach helps ensure both functionality and product quality.

For stable performance, proper storage is required:

Store in a cool, dry, ventilated environment

Recommended temperature: 0°C – 30°C

Avoid direct sunlight and moisture exposure

Keep sealed to prevent agglomeration