BOPET films are widely used in packaging, optical, and industrial fields. However, during manufacturing, processing, and use, they often suffer from stickiness. It affects their performance. Adding anti-block agents can solve this problem. Recently, nano BaSO₄ has gained attention as a new type of anti-block agent. This article explains how it works, its advantages, and its application in BOPET films.
1. What Are Anti-Block Agents?
Stickiness in plastic films occurs mainly due to:
- Vacuum Effect: When films are wound up, their surfaces stick tightly, making them hard to separate.
- Molecular Entanglement: Film surface molecules tangle under pressure, causing permanent adhesion.
Role of Anti-Block Agents
Anti-block agents create tiny bumps on the film surface. It prevents layers from sticking completely. This reduces the vacuum effect and molecular entanglement, solving the stickiness issue.
2. Limitations of Traditional SiO₂ Anti-Block Agents
Most BOPET films use micron-sized SiO₂ as an anti-block agent, but it has notable drawbacks:
- Increased Haze: SiO₂’s refractive index (1.46–1.54) is significantly different from PET’s (1.64), reducing transparency. For applications like food packaging and optical films, this is a serious limitation. Films with sufficient SiO₂ often exceed 2.5% haze.
- High Usage Requirement: Higher SiO₂ content is needed to ensure anti-block performance. It will negatively impact the film’s mechanical and optical properties.
These limitations make it necessary to find a better alternative with higher transparency and improved performance.
3. Advantages of Nano BaSO₄
Why Choose Nano BaSO₄?
- Close Refractive Index: Nano BaSO₄ has a refractive index of 1.63–1.67, closely matching PET’s 1.64. This ensures minimal impact on transparency.
- Additional Benefits:
- High Whiteness: Improves the film’s appearance.
- Corrosion Resistance: Enhances durability.
- Radiation Absorption: Adds environmental safety features.
- Increased Strength: Enhances tensile properties.
Expanding Applications: Due to its benefits, nano BaSO₄ is ideal for fields requiring high transparency, such as premium packaging and optical devices.
4. Production of Nano BaSO₄ Polyester Chips
To use nano BaSO₄ in films, it must first be made into polyester chips. The steps are:
- Dispersion: Mix nano BaSO₄ with ethylene glycol (EG) and stir to distribute it evenly.
- Sedimentation and Filtration: Remove impurities for uniform dispersion.
- Chemical Integration: Introduce nano BaSO₄ into the PET base during esterification and polycondensation.
Key Considerations The dispersion equipment, stirring speed, and grinding methods affect the particle size distribution and performance of the polyester chips.
5. How Nano BaSO₄ Improves BOPET Film
Research shows that nano BaSO₄ significantly enhances various properties of BOPET films:
- Better Anti-Stick Performance: Nano BaSO₄ creates microscopic bumps, effectively preventing film layers from sticking.
- Lower Haze: Films with nano BaSO₄ have much lower haze than those using SiO₂, making them ideal for high-clarity applications.
- Improved Strength:
- Tensile Strength: Increased by 2–2.4 times.
- Durability: Extended lifespan.
- Enhanced Optical Performance: The close refractive index match with PET ensures superior clarity for optical uses.
6. Conclusion
- An Ideal Anti-Block Agent Nano BaSO₄ effectively prevents stickiness while maintaining high transparency, outperforming traditional SiO₂ agents.
- Multifunctional Benefits It improves the film’s transparency, strength, and optical properties simultaneously.
- Broad Application Potential With its unique properties, nano BaSO₄ is well-suited for premium packaging and optical applications.
As research continues, nano BaSO₄ is set to further optimize BOPET films, meeting diverse market needs and opening new possibilities for this important chemical material.
