Characteristics of polyester
In fact, polyester is a high molecular compound, which is obtained by polycondensation of polyol and polyacid. It is a kind of engineering plastic with excellent performance and wide application. It can also be made into polyester fiber and polyester film. There are two types of polyester, polyester polyester resin and polyester elastomer.
Application of polyester
Polyester is widely used in the production of chemical fiber products. As the largest output type of chemical fiber, polyester occupies nearly 80% of the market share in the chemical fiber industry. Therefore, the market changes and development trends of the polyester series are the focus of the chemical fiber industry. At the same time, polyester also has bottles and films, which are widely used in the packaging industry, electronic appliances, medical and health, construction, automotive and other fields. Among them, packaging is the largest non-fiber application market for polyester. And an important intermediate product of multiple industry products.
Simply put, polyester is a polymer chemical reactant, not only polyester resin, but also polyester fiber, polyester polyol and so on.
Characteristics of resin
Resin is divided into natural resin and synthetic resin. Natural resin refers to the amorphous organic substances obtained from animal and plant secretions in nature, such as rosin, amber, shellac, etc.
Synthetic resin refers to resin products obtained by chemical synthesis of simple organic substances or chemical reactions of certain natural products, such as phenolic resin, polyvinyl chloride resin, etc., where synthetic resin is the main component of plastic.
Application of resin
Synthetic resin is a type of polymer synthesized by man. The most important application of synthetic resin is to make plastics. In order to facilitate processing and improve performance, additives are often added, and sometimes used directly for processing and forming, so they are often synonymous with plastic. Synthetic resins are also the basic raw materials for manufacturing synthetic fibers, paints, adhesives, insulating materials, etc. There are many kinds of synthetic resins, among which polyethylene (PE), polyvinyl chloride (PVC), polystyrene (PS), polypropylene (PP) and ABS resin are five general-purpose resins and are the most widely used synthetic resin materials.
Similarities and differences between polyester and resin
The similarities between the two are mainly manifested in the production methods of polyester and synthetic resins, both of which are polymer polymers produced by chemical reactions.
1. The physical and chemical properties and applications of the two differ greatly.
2. The two meanings are different:
Polyester mainly refers to a class of substances that contain ester groups. Equivalent to the title of metal.
Resin has two meanings, one refers to the material, equivalent to alloy, such as phenolic resin, which is equivalent to the meaning of copper-aluminum alloy, just a kind of substance. The other refers to the initial raw material that does not add any substance, that is, the masterbatch, is pure, without adding any additives or the like. It is a concept in production. Therefore, the resin mentioned in PET slicing refers to this concept. After slicing, it is one by one, which can be sold as a masterbatch, so it is also called PET resin.
Polyester resin synthesis application
In recent years, the national environmental protection regulations have become stricter, vigorously promote environmental protection and energy-saving products, implement key projects of circular economy and environmental protection, especially in the context of the introduction of consumption tax in the field of coatings, powder coatings with their "4E" characteristics, do not contain organic solvents Pollution, saving energy and resources, reducing labor intensity, high coating efficiency, and good comprehensive performance of protection and decoration are facing unprecedented development opportunities.
The output of powder coatings in my country has ranked first in the world for many years. The main types are pure epoxy type, pure polyester type and epoxy-polyester mixed type, and outdoor weather-resistant powder coatings are mostly pure polyester type. Polyester coatings are widely used, with full coatings and excellent mechanical properties, but they are limited by the narrow selection of conventional monomers for synthetic polyester and the high cost of special monomers, as well as those in the molecular structure that are easily hydrolyzed and have poor aging properties. Due to the restriction of ester bond structure, it is very difficult to further improve the aging resistance and chemical resistance of polyester powder coatings. Acrylic paint has excellent light resistance, outdoor aging performance and chemical corrosion resistance, but the resin is brittle and the mechanical properties such as impact resistance of the coating film are slightly worse.
It is precisely because the above two types of raw materials have their own strengths and shortcomings. In the field of water-based and solvent-based coatings, the combination of the two types of raw materials and the application of modification have brought huge development space for the manufacturing field.