Window profiles, facade panels, siding and other rigid PVC products for outdoor applications must perform reliably for many years. Their durability depends not only on PVC resin, stabilizer packages, processing aids, impact modifiers and fillers, but also on titanium dioxide (TiO₂), the white pigment that directly affects colour retention, gloss and profile appearance during weathering.
For Revada Plastic, titanium dioxide is one of the key components in formulations for outdoor PVC products, alongside stabilizers and modifiers.
What Causes Outdoor PVC Products to Age?
Outdoor PVC products operate under continuously changing environmental conditions. They are exposed to:
- ultraviolet radiation;
- high and low temperatures;
- day-to-night temperature fluctuations;
- humidity, condensation and snow;
- industrial emissions, dust and atmospheric contaminants;
- mechanical impacts and periodic surface cleaning.
At the material level, these factors can cause typical weathering effects:
- loss of whiteness and yellowing;
- loss of gloss and the appearance of matt areas;
- surface chalking, which forms a white powdery deposit;
- local pinking, a pink tint that can occur in cold and humid climates;
- a gradual reduction in impact strength and increased brittleness.
Some of these processes are related to the PVC matrix, but much also depends on the type and dosage of titanium dioxide used and on the pigment’s surface treatment.
The Role of Titanium Dioxide in PVC Profile Formulations
In white or light-coloured PVC profile formulations, titanium dioxide performs several key functions.
UV Protection for PVC
TiO₂ absorbs and scatters ultraviolet radiation, reducing polymer degradation beneath the profile surface. As a result, intense UV exposure is confined to a thin surface layer while the bulk of the profile remains protected.
Opacity and Whiteness
The high refractive index of rutile provides effective light scattering. This gives the pigment high opacity, helps retain whiteness and partially masks colour changes that may develop within the PVC matrix over time.
Control of Surface Weathering
Untreated TiO₂ particles can exhibit photocatalytic activity, which may accelerate polymer degradation. If the grade is unsuitable or insufficiently surface-treated, the profile surface can lose gloss more quickly, begin to chalk and show surface erosion.
The key consideration is therefore not merely the presence of titanium dioxide in the formulation, but its grade, purity, particle size, surface treatment and dosage.
Raw Materials and TiO₂ Production Technologies
Titanium dioxide is produced from naturally occurring titanium-bearing ores, including ilmenite and natural rutile. The raw material is then processed using one of two main routes: the sulfate process or the chloride process.
For PVC profiles, the production route itself is less important than the final pigment properties and the effectiveness of its surface treatment. Both sulfate- and chloride-process grades can perform well in outdoor-product formulations when requirements for low photocatalytic activity, particle size and surface treatment are met.
Crystalline Forms of TiO₂
Titanium dioxide has several crystalline forms. Two of them, rutile and anatase, are used in polymer formulations. Rutile grades are predominantly used in PVC compounds.
Characteristics of Rutile Titanium Dioxide
- high refractive index;
- good opacity;
- high weather resistance;
- low photocatalytic activity when appropriately treated;
- widespread use in PVC compounds, especially for outdoor products.
Characteristics of Anatase Titanium Dioxide
- higher photocatalytic activity, which can accelerate polymer degradation;
- typically used for indoor applications.
Critical Titanium Dioxide Parameters for PVC
For PVC compounds, particularly those intended for outdoor use, the following pigment characteristics are important:
- low photocatalytic activity;
- low levels of metallic impurities;
- appropriate particle size and a narrow particle-size distribution;
- low tendency to agglomerate;
- low abrasiveness;
- effective surface treatment.
These parameters determine TiO₂ behaviour during processing and the durability of the finished product.
Low pigment abrasiveness is particularly important for processors because it directly affects the wear of mixer blades, screws, dies and calibration tooling. The rutile titanium dioxide grades supplied by Revada Plastic have controlled low abrasiveness due to optimised particle size and effective surface treatment. This helps reduce equipment wear and maintain stable production during long line operating cycles.
Why TiO₂ Particles Are Surface-Treated and How This Affects Product Service Life
Modern titanium dioxide grades used as pigments in PVC compounds are typically provided with multilayer surface treatment. These coatings commonly include silicon, aluminium and zirconium oxides, together with organic compounds.
Such coatings:
- reduce the photocatalytic activity of titanium dioxide;
- reduce agglomeration;
- improve dispersion;
- reduce abrasiveness;
- improve resistance to gloss loss and chalking.
Coating quality is directly linked to profile durability in real operating conditions. In industrial PVC formulations, it has both aesthetic and economic importance: high-quality particle surface treatment can improve weather resistance, reduce chalking and lower abrasive wear on processing equipment.
Titanium Dioxide Grades in the Revada Plastic Range
Revada Plastic supplies rutile titanium dioxide grades for PVC compounds under its own Revatiox brand.
Revatiox rutile grades are produced with multistage surface treatment based on silicon and aluminium oxides, as well as organosilicon compounds. This provides stable dispersion in PVC compounds, high opacity, resistance to chalking and controlled low abrasiveness during processing.
The appropriate Revatiox grade is selected according to shade requirements, the stabilizer system, operating conditions and processing characteristics. Titanium dioxide grades supplied by Revada Plastic have undergone climatic testing in PVC products under operating conditions in Russia and the CIS, including exposure to ultraviolet radiation, temperature fluctuations and high humidity. The tests confirmed stable whiteness, gloss retention, the absence of pronounced surface chalking and resistance to shade change during weathering. The quality and consistency of these grades are also confirmed by their use by major Russian and international manufacturers of PVC profiles and facade materials.
The Revada Plastic Approach
When working with titanium dioxide for PVC compounds, we:
- select the appropriate grade for the customer’s formulation and equipment;
- assess compound performance in tests for colour, gloss and chalking;
- consider the pigment’s effect on processing and tooling wear;
- help optimise the formulation for the product’s operating conditions.
As a supplier of PVC additives, our role extends beyond supplying raw materials. We help ensure stable formulation performance and predictable product behaviour throughout its service life. Particular attention is paid to the balance between weather resistance and processability, including pigment abrasiveness and its effect on equipment service life.
