How to Select TiO₂ Grades for Coatings, Plastics, and Paper

Introduction

Selecting the appropriate TiO₂ grade requires understanding both the application requirements and the relevant pigment properties. This guide provides a systematic approach to grade selection across the major application segments.

Key Selection Criteria

Before evaluating specific grades, define your requirements in these areas:

1. **Optical requirements**: Hiding power, brightness, undertone

2. **Durability requirements**: Exterior exposure, UV stability

3. **Processing requirements**: Dispersion, viscosity, compatibility

4. **Economic requirements**: Cost targets, availability

Coatings Applications

Architectural Coatings

**Interior paints** prioritize:

• Good hiding power at economical loading
• Easy dispersion in waterborne systems
• Stable viscosity

Suitable grades: General-purpose rutile with alumina treatment. Both chloride and sulfate process grades work well.

**Exterior paints** prioritize:

• Chalk resistance and color retention
• UV stability
• Moisture resistance

Suitable grades: Durable rutile grades with dense silica/alumina treatment. Chloride process preferred for premium exterior applications.

Industrial Coatings

**General industrial** (machinery, equipment):

• Consistent quality for reproducibility
• Good gloss potential
• Chemical resistance

Suitable grades: Mid-range durable rutile grades with balanced properties.

**Automotive OEM**:

• Maximum durability (10+ year warranties)
• Excellent DOI (distinctness of image)
• Tight batch-to-batch consistency

Suitable grades: Premium chloride process rutile with maximum durability treatment.

Plastics Applications

Key Considerations

Plastics applications require attention to:

• **Lacing resistance**: Critical for polyolefin film and fiber
• **Thermal stability**: Processing temperatures may exceed 250°C
• **Dispersion**: Pigment must disperse completely in polymer matrix
• **Moisture content**: Low moisture prevents processing defects

Grade Selection by Polymer Type

**Polyolefins (PE, PP)**:

Select grades specifically designed for polyolefin compatibility with organic surface treatments for lacing resistance.

**PVC**:

General-purpose rutile grades work well. Consider thermal stability for rigid PVC processing.

**Engineering plastics**:

Higher processing temperatures require grades with excellent thermal stability. Consider organic treatment levels.

Masterbatch Production

Masterbatch typically uses:

• High TiO₂ loading (50-70%)
• Grades with excellent dispersion characteristics
• Low moisture content grades

Paper Applications

Coated Paper

Paper coating applications consider:

• **Brightness contribution**: Both hiding and brightness enhancement
• **Abrasion**: Softer particles reduce coating head wear
• **Cost efficiency**: High-volume applications are cost-sensitive

Anatase grades remain popular for paper due to lower cost and softer particles. Rutile provides better hiding per unit weight.

Decorative Laminates

Laminate applications require:

• High brightness
• Good hiding of substrate
• UV stability for light-exposed surfaces

Standard rutile grades with moderate durability treatment are commonly specified.

Specification Development

When developing specifications, consider:

1. **Critical properties**: Identify 3-5 properties that directly affect your product performance

2. **Test methods**: Specify standard test methods (ISO, ASTM) for consistency

3. **Tolerance ranges**: Set realistic tolerances based on actual product needs

4. **Incoming QC**: Define practical receiving inspection procedures

Multi-Sourcing Considerations

For supply security, identify 2-3 equivalent grades from different suppliers. Consider:

• Qualification testing in your system
• Regional availability and logistics
• Price stability and contract terms
• Technical support availability

Conclusion

Effective TiO₂ grade selection requires matching pigment properties to specific application requirements. Start with the key performance criteria, narrow options by process type and treatment level, then validate through testing in your actual system.