What are the raw material recycling processes for polyester fiber nonwoven fabrics?

2025-12-03 13:59:53

The raw material recycling process for polyester nonwoven fabrics mainly includes three methods: physical recycling, chemical recycling, and energy recovery. Physical recycling involves mechanically crushing, washing, melting, and regranulating waste nonwoven fabric to form reusable polyester granules. The key to this method is separating impurities and contaminants to ensure the purity of the recycled material. The washing stage is particularly important, requiring the use of specific solvents or water-based cleaning agents to remove oil and other deposits. Precise temperature control is necessary during the melting process to avoid excessive degradation of the polyester molecular chains. The advantage of physical recycling is its relatively simple process and low energy consumption, but the performance of the recycled material may be somewhat degraded.

Chemical recycling involves chemically decomposing polyester fibers into monomers or oligomers, which are then polymerized to regenerate polyester raw materials. Commonly used chemical recycling methods include hydrolysis, alcoholysis, and glycolysis. Hydrolysis decomposes polyester into terephthalic acid and ethylene glycol under high temperature and pressure conditions; these two monomers can be reused to produce polyester fibers. Alcoholysis decomposes polyester into oligomers using alcohol solvents, which are then purified and polymerized to obtain new polyester materials. Chemical recycling offers the advantage of yielding recycled polyester with properties close to virgin materials, but the process is complex, and equipment investment and operating costs are high.

Energy recovery involves incinerating waste nonwoven fabrics to generate electricity or heat. Polyester fibers have a high calorific value, making them suitable for fuel. The key to energy recovery is controlling pollutant emissions during combustion, particularly the formation of harmful substances such as dioxins. Modern incineration technologies are typically equipped with excellent flue gas purification systems to ensure environmental compliance. Energy recovery is suitable for waste nonwoven fabrics that cannot be recycled through physical or chemical methods, but resource utilization is relatively low.

Besides the three main recycling processes mentioned above, some emerging recycling technologies are under development, such as biodegradable recycling and supercritical fluid recycling. Biodegradable recycling uses microorganisms or enzymes to break down polyester fibers into smaller molecules, which are then converted into useful chemicals through fermentation or other biotechnologies. Supercritical fluid recycling uses supercritical fluids (such as carbon dioxide) to dissolve polyester, which is then separated by depressurization or temperature changes. While these new technologies are not yet widely used, they have the potential to be environmentally friendly and highly efficient.

The selection of recycling processes requires comprehensive consideration of the pollution level of waste nonwoven fabrics, the performance requirements of recycled materials, economic costs, and environmental impact. Physical recycling is suitable for processing relatively clean waste nonwoven fabrics, chemical recycling is suitable for applications with high material performance requirements, and energy recovery is a later choice. In the future, with technological advancements and stricter environmental protection requirements, recycling processes for polyester fiber nonwoven fabrics will become more diversified and efficient.