Polyester chips are used in our lives normally, such as printing and lamination, metallization, embossing, holograms, thermal lamination, etc. Have you ever wondered how to make polyester chips? In this article, we will take you to have a close look at the production of polyester chips.
Polyethylene Terephthalate (PET) Chips form the fundamental building blocks of plastic materials or polymers. These chips come in two primary variations based on their structural formation: the amorphous type, referred to as Bright or Super Bright Chips due to their transparency, and the semi-crystalline form known as PET Semi-Dull Chips. PET Chips play a vital role in the production of PET Film and find widespread use in various industries, particularly in textile applications, supplying yarn-producing entities with finishes like semi-dull, full-dull, and super-bright variations.
The creation of polyester chips is an integral part of the petrochemical industry. These chips are derived from the polycondensation reaction involving pure terephthalic acid and monoethylene glycol, which are the primary components of PET. The raw materials used in producing PET chips are PTA (purified terephthalic acid) and MEG (monoethylene glycol), both sourced from petroleum. The manufacturing process begins with the conversion of petroleum into naphtha, followed by refining processes like catalytic reforming, aromatic hydrocarbon extraction, and isomerization to obtain PX (purified xylene). PX is further processed into PTA through procedures involving acetic acid as a solvent, air oxidation, and hydrogenation purification. MEG, on the other hand, is created through the reaction of ethylene oxide, a derivative of the petrochemical industry.
Presently, the predominant method for polyester synthesis involves the direct reaction process using PTA and EG. This process encompasses esterification and polycondensation reactions and consists of several key stages:
Slurry Preparation: Blending PTA and EG to form a suitable slurry for esterification.
Additive Mixing: Preparation of various additives necessary for the production process along with EG.
Esterification: Reaction between PTA and EG under specific temperature and pressure conditions to produce bis(2-hydroxyethyl) terephthalate (BHET) and water. Water is separated through distillation and managed in the wastewater treatment system.
Polymerization Reaction: BHET undergoes polymerization at high temperatures, in the presence of a catalyst, and under vacuum.
Vacuum Pumping: Utilizing steam from the esterification tower to create a vacuum for efficient removal of EG, ensuring proper polymerization.
EG Recovery: Purification of EG produced during the process, with around 95% recycled and combined with PTA to create a slurry.
Pelletization: Processing dried and crystallized polyester chips into specific-sized granules through filtration and pelletization.
Solid-Phase Polymerization: Subjecting polyester chips to solid-phase polymerization in a nitrogen atmosphere at a specific temperature to enhance polymerization and viscosity while releasing low-molecular-weight byproducts.
Polyester chips serve as crucial elements in various industries such as textiles, plastic packaging, and agriculture. These chips are classified into three main grades: Textile grade, Bottle grade, and Film grade.
In the production of PET films, high-quality chips devoid of Silica & CiO2 contents play a significant role. These film-grade chips, manufactured by countries like India, China, Vietnam, and South Korea, find application in printing, lamination, metallization, embossing, holography, and thermal lamination.
Within the textile industry, PET chips are employed in manufacturing diverse polyester fibers like short fiber and long fiber. The yarn or textile grade chips come in various types such as Super Bright (BR Chips), Semi Dull (SD Chips), Cationic Semi Dull, and Cationic Super Bright PET Chips (CD Chips). ECDP (easy cationic-dyeable polyester) chips can be blended with synthetic fibers like nylon, acrylic, and natural fibers such as wool, hemp, and cotton, producing different blended fibers. These chips, tailored to specific sizes, are manufactured in countries like India, China, Taiwan, Malaysia, South Korea, and Saudi Arabia.
Bottle-grade PET chips are another type extensively used in the production of plastic bottles. These chips are characterized by low processing temperatures, excellent transparency, and a highly finished appearance. They come in three primary types: suitable for manufacturing drinking water bottles and mineral water bottles; those offering enhanced strength for carbonated drinks bottles, small bottles for edible oil, liquor, medicines, and pet sheets; and the third type used in making large packaging bottles for carbonated drinks and 3-5 gallon water bottles.
Polyester chips, the fundamental building blocks of plastic materials, play an indispensable role in various industries, including textiles, packaging, and more. The process of making polyester chips involves a complex series of steps starting from raw materials sourced from petroleum to a refined product used for an array of applications. These chips, categorized into Textile grade, Bottle grade, and Film grade, find extensive use in the production of PET films, polyester fibers for textiles, and plastic bottles. Their diverse variations cater to specific industrial needs, such as enhancing finishes for textiles, ensuring transparency and strength in bottles, and enabling numerous applications like printing, lamination, metallization, embossing, and thermal lamination. Understanding the intricate manufacturing process and diverse uses of polyester chips sheds light on their pivotal role across multiple sectors, driving innovation and development within various industries. Check at Wankai, the most professional polyester chips supplier in China.