Purified Terephthalic Acid (PTA)—also known as Terephthalic Acid—is a critically important chemical raw material. It serves as a key feedstock in the manufacturing of PP (polypropylene) and PET (polyester), and acts as an intermediate material used to produce a wide range of substances, including specialty chemical fibers, plastics, polyester fabrics, polymers, and latex.
Physicochemical Properties
Purified Terephthalic Acid (PTA) is a colorless, odorless, and extremely dry liquid. It exhibits good solubility; it dissolves readily in water and is also soluble in various organic solvents, though it remains insoluble in alkane-based solvents. Its density is approximately 1.252 g/ml, with a boiling point of 164.6°C, a melting point of -46.2°C, and a refractive index of 1.4845. It demonstrates excellent chemical stability.
The following precautions should be observed when handling Purified Terephthalic Acid:
Protection from Sunlight: Purified Terephthalic Acid is susceptible to ultraviolet radiation; direct exposure to sunlight can trigger chemical reactions that lead to its deterioration. If left exposed to sunlight, the material may degrade and lose its intended properties. Therefore, during storage, handling, and transportation—whether indoors or outdoors—Purified Terephthalic Acid must be shielded from direct sunlight. It is highly recommended to use shading devices or to store and utilize the material in locations that provide adequate shelter from the sun.
Prevention of Contamination by Inorganic Salts: Purified Terephthalic Acid is chemically reactive and can degrade—thereby losing its utility—if it comes into contact with certain substances. Consequently, contact with inorganic salt deposits—such as limestone or sulfates—must be strictly avoided; otherwise, chemical reactions may occur, compromising the purity and quality of the material.
Application Areas
Purified Terephthalic Acid (PTA) is primarily utilized in the production of polymer plastics, engineering plastics, synthetic dyes, and polyester fibers. Additionally, it is employed in the recycling of plastics (specifically PET) and in the manufacture of polyvinyl chloride (PVC) plastics, serving as a key raw material for synthetic resins and coatings. Its primary applications include:
Polymer Plastics
Purified Terephthalic Acid plays a central role in the production of polymer plastics and engineering plastics—such as the new generation of high-performance polystyrene, polymethacrylic acid, and polyamide-based plastics. Purified Terephthalic Acid (PTA) with a purity exceeding 99% can also be utilized in the manufacture of various types of molded plastic products—including polyethylene, polypropylene, polyvinyl chloride (PVC), polymethyl methacrylate (PMMA), and polyamide plastics. These materials are employed in the production of goods for the electronics, machinery, automotive, food, healthcare, and construction industries, as well as for repair tools and appliances.
Polyester Fibers
PTA is also integral to the production of polyester fibers. Polyester fibers are defined as fine fibers processed from polyester polymers and their blends. They serve as essential raw materials in the manufacture of apparel fabrics, webbing, automotive interiors, furniture upholstery, architectural decorations, and similar products. Polyester fibers can be produced using PTA—alongside materials such as PVC and methyl methacrylate—through various processing methods, including splicing, molding, extrusion, or biaxial stretching.
Economic Benefits
As a fibrous material, Purified Terephthalic Acid (PTA) possesses significant economic value. It serves as a critical raw material in manufacturing sectors such as construction, shipbuilding, apparel, sporting goods, and furniture. It facilitates the recycling and recovery of post-consumer polyethylene terephthalate (PET) fibers, and can also be directly utilized to manufacture non-fibrous products—such as various plastic goods—thereby enabling enterprises to enhance their production efficiency.
Purified Terephthalic Acid (PTA)—also referred to as coal-based terephthalic acid—is a precursor to polyester polymers. It is synthesized from coal tar and other hydrocarbon compounds through a complex process involving cracking, oxidation, washing, and isomerization reactions; its primary feedstock is styrene (PET). PTA acts as the primary precursor for the terephthalate backbone structure of polyesters. It can react with chemical substances such as epoxy alcohols to form polyurethanes, making it adaptable to a wide range of applications and suitable for the production of diverse products, including paints, construction materials, automotive components, pharmaceuticals, and dyes.
PTA is a versatile organic acid that plays a pivotal role in the field of polymer synthesis. It possesses excellent thermal stability, high thermal insulation strength, resistance to acids and alkalis, good solubility, and low heat absorption—characteristics that facilitate heat treatment processes and enhance the flow properties of industrial plastics. It can serve as a substitute for activated carbon as a porous carbon matrix material and is widely utilized in fields such as batteries, analytical testing, dehumidification equipment, catalysts, and metal surface polishing.
PTA features an ultra-high molecular weight and a slender, continuous structure, which enables it to provide a powerful “skin effect.” Within polymer structures, it can construct “thermally conductive” bridges, thereby endowing materials with superior heat resistance, fire resistance, and thermal stability. It finds application in gas-phase systems and metal surface polishing materials, as well as across diverse industries including coatings, plastics, and ceramics. The addition of PTA enhances a product’s corrosion resistance and improves its thermal performance; furthermore, it ensures the material’s hardness and stability, boosts its impact resistance, and significantly improves its resistance to washing and high temperatures.
Additionally, PTA can function as a polymeric wetting agent in polymer processing to enhance various mechanical and physical properties—such as material flowability, adhesion, and antistatic capabilities. It exhibits excellent resistance to degradation and remains uncontaminated over long periods; particularly in harsh operating environments, it facilitates more efficient polymer synthesis while yielding lower degradation indices. The SGA-type structure of PTA exerts a profound influence on polymer shrinkage and melt permeability. In the mechanical engineering sector, its superior wear resistance and impact strength—relative to other materials—enable it to better meet the rigorous demands of industrial applications. In the aerospace industry, as its scope of application continues to expand, it is increasingly utilized in the manufacture of mechanical components, engine structural parts, molded components, and polyolefins; its superior performance characteristics are proving instrumental in meeting the evolving requirements of the aerospace domain.
PTA occupies a pivotal position within the industrial landscape. It finds application across a multitude of sectors—including home appliances, construction materials, textiles, pharmaceuticals, dyes, the automotive industry, and aerospace—where, as a vital constituent of polymeric materials, it plays a critical role in the production of a vast array of products. The continued advancement of PTA holds the potential to significantly reduce manufacturing costs, open up new avenues for development across numerous fields, and inject fresh vitality into the progress of society as a whole.
