THE EMERGING FUTURE FOR POLYESTER

Polyester (PET) is the most widely used fibre in the apparel industry, accounting for around 52% of the total volume of fibres produced globally. The apparel industry accounts for around 32 million tons of the 57 million tons of polyester used each year [1]. It is used widely in technical textiles as well.

RASHI TRIVEDI, ANNU JAIN

Introduction

Polyester is polymerized from the monomer ethylene. Polyesters can be thermoset or thermoplastic, saturated or unsaturated. The two main types of polyester are PCDT (poly-1, 4-cyclohexylene-dimethylene terephthalate) and PET (polyethylene terephthalate) [2].

PET

PET is among those plastics which are an important part of your everyday life. It is an important commercial polymer having application ranging from packaging, fabrics, films, moulded parts for automotive, electronics... and many more. You can find this famous clear plastic around you as water bottle or soda bottle container.

Polyethylene terephthalate (PET or PETE) is a general-purpose thermoplastic polymer which belongs to the polyester family of polymers. Polyester resins are known for their excellent combination of properties such as mechanical, thermal, chemical resistance as well as dimensional stability.

Polyethylene Terephthalate or PET products are 100% recyclable and is the most recycled plastic worldwide. PET can be easily identified by its recycling code #1. Low diffusion coefficient makes PET much more suitable than other plastic materials for use as a recovered, recycled material.

Post-consumer PET bottles are collected and processed through a series of special washing processes or by a chemical treatment to break down the PET into its raw materials or intermediates which are further used to produce recycled PET (rPET) flakes. PET bottles and containers that find their way to the landfill pose no risk of harm or leaching. Since the polymer is inert, it is resistant to attack by micro-organisms, and won't biologically degrade. PET bottles can also easily crush flat and hence, takes up relatively little landfill space [3].

PCDT

The process of creating PCDT polyester is similar to the process of creating PET polyester, but this polyester variant has a different chemical structure. While PCDT also consists of ethylene glycol reacted with dimethyl terephthalate, different production processes are used to make these two common polyester variations. While PCDT polyester is not as popular as PET polyester, it is more elastic which makes it ideal for certain applications. PCDT polyester is also more durable than PET polyester, so this fabric is frequently preferred for heavy-duty applications like upholstery and curtains [4].

Recycling process

Polyester is made from recycled plastic bottles which cuts out the need for petroleum and coal extraction. Recycled polyester literally starts at the dump to collect plastic bottles that don’t belong in landfills. From there, the plastic bottles are shredded into flakes by a machine. Those flakes are melted down into pellets, then the pellets are extruded into yarn. The yarn is then knitted, cut, and sewn into clothing just like any other yarn[5]. Today, mechanically recycled polyester from plastic water bottles makes up the vast majority of recycled polyester than chemically recycled polyester [1].

Brands promoting rPET