Tribasic Lead Sulfate (TBLS)
Product Overview
Tribasic Lead Sulfate (TBLS) is a highly effective lead-based PVC stabilizer widely used in applications requiring excellent thermal stability, electrical insulation, and long-term durability.
Chemically identified as 3PbO·PbSO₄·H₂O (CAS No. 12202-17-4), TBLS is supplied as a white microfine powder with excellent performance in high-temperature PVC processing.
The stabilizer is particularly suitable for PVC cable compounds, rigid pipes, and industrial PVC products, where strong resistance to heat and environmental stress is required.
Key Functional Characteristics
High Temperature Stability
Tribasic Lead Sulfate can withstand PVC processing temperatures exceeding 200°C, providing excellent thermal stability during extrusion and molding processes.
Electrical Insulation Performance
The material offers strong electrical insulation properties, making it particularly suitable for PVC cable insulation and power cable sheathing applications.
Environmental Resistance
TBLS remains stable under dry and light-protected storage conditions. However, exposure to moisture and direct light may cause discoloration or gradual decomposition, therefore controlled storage is recommended.
Compared with certain organic stabilizers, TBLS helps reduce the risk of additive migration and improves the long-term service life of PVC products.
Key Specification Parameters
Tribasic Lead Sulfate typically conforms to Chinese Chemical Industry Standard HG2340-92, which classifies the product into Premium Grade, First Grade, and Qualified Grade.
Core Quality Indicators
Lead Content (calculated as PbO)
- Premium / First Grade: 88.0 – 90.0%
- Qualified Grade: 87.5 – 90.5%
Sulfur Trioxide (SO₃)
- Premium / First Grade: 7.5 – 8.5%
- Qualified Grade: 7.0 – 9.0%
Loss on Heating
- Premium Grade: ≤ 0.30%
- First Grade: ≤ 0.40%
- Qualified Grade: ≤ 0.60%
Residue on 75 μm Sieve
- Premium Grade: ≤ 0.30%
- First Grade: ≤ 0.40%
- Qualified Grade: ≤ 0.80%
Physical Properties
- Density: Approximately 7.1 g/cm³
- Melting Point: Approximately 820°C
- Solubility: Slightly soluble in water; soluble in hot ammonium acetate and alkaline solutions
Application Areas
Tribasic Lead Sulfate is commonly used in PVC formulations and industrial applications that require high heat stability and durability.
Electrical Cable Insulation
TBLS is widely used in PVC cable insulation and jacket compounds, including:
- High-voltage power cables
- Heat-resistant cable insulation
- Mining cables
- Marine cables
- Industrial equipment power cables
The stabilizer enhances thermal resistance, electrical insulation, and long-term reliability.
Rigid PVC Products
Typical applications include:
- Industrial pipes and ventilation ducts
- Building drainage systems
- Chemical storage tank linings (non-potable water applications)
It is also used in injection-molded PVC structural components, such as equipment housings and instrument panel supports.
Flexible PVC and Specialty Materials
Used in selected industrial flexible PVC products, including:
- Industrial synthetic leather used for protective covers and equipment dust shields
- Foam materials and plastic adhesives for sealing gaskets and coating substrates
- Industrial inflatable products such as buoys and protective airbags
Lead-Acid Battery Manufacturing
Tribasic Lead Sulfate can also be used as an additive in lead-acid battery positive lead paste, improving battery performance and stability.
Industrial Coatings and Pigments
TBLS may be used in:
- Heavy-duty corrosion-resistant coatings, including ship bottom paints and anti-rust primers for steel structures
- As a light-stable white pigment (C.I. Pigment White 2) in certain industrial identification coatings
Restricted Applications
Due to the presence of lead, this material is not suitable for certain applications, including:
- Transparent PVC products where optical clarity is required
- Food-contact materials
- Pharmaceutical or medical applications
- Consumer products with potential lead exposure risks
Packaging and Storage
Packaging
Standard packaging includes:
- Double-layer protective packaging consisting of:
- Polyethylene (PE) inner bag
- Laminated woven bag or cardboard drum
Standard packaging unit:
- 25 kg per bag
Storage and Handling
Recommended storage conditions:
- Store in a cool, dry, and well-ventilated environment
- Relative humidity: ≤ 50%
- Protect from direct light and moisture
- Keep away from acidic and alkaline substances
Stacking recommendation:
Maximum 3 layers to prevent packaging deformation.
Shelf Life
- 24 months under recommended storage conditions.
After opening, packaging should be resealed tightly and the product used within 6 months to prevent moisture absorption.
