Traditional infusion sets are made of PVC, and high-performance polyolefin thermoplastic elastomer (TPE) is considered as a safer and higher-performance material for making disposable infusion sets. PVC is a polymer material, and its full name is polyvinyl chloride. Its main component is polyvinyl chloride, and the simple structure of its monomer is CH2=CHCl.
Chemical and physical properties:
Rigid PVC is one of the most widely used plastic materials. PVC is actually a vinyl polymer, and its material is an amorphous material. In practical use, stabilizers, lubricants, processing AIDS, pigments, impact agents and other additives are often added to PVC materials. It is nonflammable, high strength, weatherability and excellent geometric stability. PVC has strong resistance to oxidants, reductants and strong acids. However, it can be corroded by concentrated oxidizing acids such as concentrated sulfuric acid and concentrated nitric acid, and is not suitable for contact with aromatic hydrocarbons and chlorinated hydrocarbons.
The melting temperature of PVC during processing is a very important technological parameter. If this parameter is not suitable, it will lead to the problem of material decomposition. PVC has poor fluidity and narrow processing range. In particular, PVC materials with large molecular weight are more difficult to process (this material usually needs to add lubricants to improve its flow characteristics), so PVC materials with small molecular weight are usually used. The shrinkage of PVC is quite low, generally 0.2~0.6%.
Technological conditions of injection mold
Drying treatment: drying treatment is usually not needed.
Melting temperature:185 ~ 205 c; Mold temperature: 20 ~ 50 C.
Injection pressure: up to 1500bar holding pressure: up to 1000bar injection speed: In order to avoid material degradation, it is generally necessary to use a considerable injection speed.
Runner and gate: All conventional gates can be used. If machining smaller parts, it is best to use needle gate or submerged gate; For thicker parts, it is best to use fan gate. The minimum diameter of needle gate or submerged gate should be1mm; The thickness of the sector gate should not be less than 1 mm.
Typical uses: PVC has the outstanding characteristics of rich raw materials (oil, limestone, coke, salt and natural gas), mature manufacturing technology, low price and wide application. Now it has become the second largest general resin in the world, accounting for 29% of the total consumption of synthetic resin in the world. PVC is easy to process, and can be processed by molding, laminating, injection molding, extrusion, calendering and blow molding. PVC is mainly used to produce artificial leather, film, wire sheath and other plastic soft products, water supply pipes, household pipes, house wall panels, commercial machine shells, electronic product packaging, medical equipment, food packaging, and also can produce plastic hard products such as plates, doors and windows, valves and so on.
PVC can be divided into soft PVC and hard PVC. Among them, hard PVC accounts for about 2/3 of the market and soft PVC accounts for 1/3. Soft PVC is generally used for floors, ceilings and leather surfaces, but its application is limited because it contains softener (which is also the difference between soft PVC and hard PVC), which is easy to become brittle and difficult to store. Rigid PVC contains no softener, so it is flexible and easy to form, not fragile, non-toxic and pollution-free, and has long storage time, which is of great development and application value. Hereinafter referred to as PVC. The essence of PVC is a kind of vacuum plastic film, which is used for surface packaging of various panels, so it is also called decorative film and adhesive film, and is used in building materials, packaging, medicine and other industries. Among them, the building materials industry accounts for the largest proportion, accounting for 60%, followed by the packaging industry and several other small-scale application industries.
PVC is a kind of polyvinyl chloride plastic.
Simply put, the aqueous solution of salt is chemically decomposed under the action of electric current. This process produces chlorine, caustic soda and hydrogen. Refining and cracking petroleum or gasoline can produce ethylene. When chlorine and ethylene are mixed, dichloroethylene will be produced; Dichloroethylene can be converted into chloroethylene, which is the basic component of PVC. During the polymerization process, chlorinated vinyl molecules are linked together to form PVC chains. The PVC produced in this way is white powder. It cannot be used alone, but it can be mixed with other ingredients to make many products.