Views: 0 Author: Site Editor Publish Time: 2026-02-25 Origin: Site
In the plastics industry, molecular sieve are widely used for deep dehumidification and drying of hygroscopic engineering plastics, such as PET, PA, PC, and ABS. This drying process is a critical pre-treatment step to ensure the quality and performance of the final plastic products.
The core principle is based on the microporous structure of molecular sieve adsorbents, which selectively adsorb moisture impurities from plastic raw materials, reducing the moisture content to ppm levels. This effectively prevents defects such as hydrolytic degradation, silver streaks, and bubbles during subsequent high-temperature processing.
Working Principle of Molecular Sieve Drying
Hot and humid process air passes through the molecular sieve adsorption bed, where moisture is captured and the air is deeply dried.
Once the molecular sieve becomes saturated, the system switches to regeneration mode, introducing hot air at 200–350°C to desorb and remove the adsorbed moisture.
After regeneration, the molecular sieve bed is cooled down to operating temperature to restore optimal adsorption performance. Twin-tower or multi-tower systems alternate between adsorption and regeneration, ensuring continuous and stable deep dehumidification.
Selection of Molecular Sieve Desiccants
CHEMXIN 3A molecular sieve is the preferred choice for plastic drying applications. With a pore size of only 3 Å, it efficiently removes water while minimizing the adsorption of larger volatile organic molecules present in plastics, such as monomers and plasticizers. This selectivity ensures long service life and stable performance.
In addition to static water adsorption capacity, crushing strength and abrasion resistance are also critical factors, as they directly affect whether the molecular sieve can withstand continuous airflow without generating dust, which would otherwise reduce system lifespan and contaminate plastic materials.
Typical Applications
1.Polyethylene Terephthalate (PET) Industry
The largest applications include bottle flake recycling, pelletizing, and fiber production. Deep drying is essential to prevent hydrolytic degradation and to maintain product viscosity and mechanical strength.
2.Polyamide (Nylon, PA) Processing
Whether for automotive components or electronic parts, thorough drying is crucial to achieving high strength and toughness.
3.Optical-Grade and Specialty Plastics
For materials such as polycarbonate (PC) and PMMA used in lenses and light guides, even trace moisture can cause optical distortion and surface defects.
High-temperature engineering plastics like PEEK and PEI require even higher processing temperatures and stricter moisture control.
About Chemxin:
Guangzhou Chemxin Environmental Material Co., Ltd. has specialized in the production of molecular sieve, activated molecular sieve powder, activated alumina, and ceramic ball for over 24 years. Our factory covers 50,000 square meters and employs more than 250 staff members, including a dedicated R&D team committed to innovation and quality.
If you have any inquiries or requirements, please feel free to contact us at any time. We are here to provide you with professional solutions and reliable service.
E: info@chemxin.com
