Application of Barium Sulfate in High-Gloss PP
Mineral-filled PP is widely used in modified polypropylene (PP) materials. Common fillers include barium sulfate, talc, and calcium carbonate. This article explores barium sulfate’s application and advantages in high-gloss PP.
1. Market Demand and Characteristics of High-Gloss PP
High-gloss PP is gaining popularity as a replacement for ABS and HIPS. Compared to ABS, it has lower density, cost, and flexible modification. In household appliance casings, high-gloss, paint-free PP has become the preferred material.
2. Formulation Design of High-Gloss PP
The basic formula includes homopolymer PP resin and precipitated barium sulfate, sometimes with talc and nucleating agents. Understanding PP properties and selecting suitable fillers are crucial. Precipitated barium sulfate stands out due to its unique performance.
3. Impact of Fillers on PP
Gloss Fillers affect PP gloss based on their microscopic shape. Their impact order is: precipitated barium sulfate < barite < kaolin < calcium carbonate < talc. Spherical fillers have the least impact, while flaky fillers affect gloss the most.
4. Types and Preparation of Barium Sulfate
There are two main types of barium sulfate used in industry:
Barite Powder: Milled from natural barite, containing minor calcium carbonate and barium carbonate impurities. Used mainly in coatings and pigments.
Precipitated Barium Sulfate: Chemically synthesized with over 98% purity. It is prepared via barite reduction or barium carbonate-sulfate reaction, with the former being more common in China.
5. Key Performance Indicators of Precipitated Barium Sulfate
In modified plastics, precipitated barium sulfate must meet key performance requirements:
High-Temperature Resistance: It must remain stable at PP’s 200°C processing temperature without discoloration.
Whiteness: It provides superior whiteness compared to calcium carbonate and talc, enhancing product appearance.
Particle Size & Dispersion: Smaller particles improve gloss, but excessive fineness may cause uneven dispersion.
Impact on PP Properties: It has minimal impact on mechanical properties but requires optimization for impact strength and heat resistance.
6. Conclusion
Precipitated barium sulfate is a key filler in high-gloss PP due to its whiteness, heat resistance, and gloss enhancement. Optimized formulations expand its applications in household appliances, reducing costs and improving competitiveness.
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