Amid the textile industry's pursuit of sustainable development, recycled yarn has become a key environmentally friendly option. It's widely believed that its lifecycle carbon emissions can be approximately 70% lower than those of virgin polyester.
Recycled yarn bypasses the process of crude oil extraction and refining to produce PET chips. However, the production of virgin polyester begins with crude oil or natural gas extracted from underground. This initial step carries a significant environmental burden: exploration, drilling, and extraction consume significant amounts of energy and generate emissions. Crude oil then undergoes a complex refining process to produce intermediate products such as naphtha. The most critical and energy-intensive step is transforming naphtha and other raw materials into PET chips through a complex series of chemical reactions. This chemical reaction typically occurs at temperatures of 250-300°C and high pressure, continuously consuming vast quantities of fossil fuels such as coal, natural gas, or oil as energy, and directly generating significant amounts of carbon dioxide. The carbon dioxide generated by producing one ton of virgin PET chips is substantial.
Recycled yarn is derived from discarded PET materials, most commonly recycled beverage bottles or textile waste. The process of converting this waste into usable yarn consumes far less energy and emissions than producing virgin PET chips. The main steps include collection, sorting, crushing, deep cleaning, melt filtration, and re-pelletization or direct spinning. While collection, transportation, cleaning, and melting also require energy, the energy intensity of these processes is significantly lower than that of producing and polymerizing from crude oil and far less than the energy required for complex petrochemical synthesis reactions from scratch. Physical recycling avoids most of the high-carbon chemical reactions.
While chemical recycling typically consumes more energy and emits less carbon than physical recycling, it generally remains lower than virgin routes. The chemical process involves chemically depolymerizing the discarded PET, breaking it down into monomers or small-molecule intermediates, which are then repolymerized into PET. This process effectively closes the raw material loop and produces high-quality products. However, its overall carbon emissions are currently higher than those of physical recycling. However, even chemical production still produces lower carbon emissions than virgin polyester, according to most studies and certification data.
The use of discarded PET bottles or textile waste as raw materials in the production of recycled yarn inherently provides significant environmental value. This reduces landfill waste and the need for incineration, both of which lower carbon emissions. While these avoided emissions are typically not included in the carbon footprint of the product itself, they are considered a significant positive environmental benefit of recycled materials when considering the overall environmental impact of the entire material system, supporting the estimated 70% reduction in emissions.
| Recycling Type | Process Description | Emission Level |
|---|---|---|
| Physical Recycling | Collection cleaning melting spinning | Lowest emissions |
| Chemical Recycling | Depolymerization and repolymerization | Moderate emissions |
| Waste Management | Not applicable | Avoids disposal emissions |
