The polyvinyl chloride (PVC) calendered film is obtained by a calendering process, and the calendering is to pass the heated plastic through a gap between one or more pairs of horizontally rotating horizontal rolls to cause the material to undergo extrusion and elongation.

It becomes a process of a thin article having a certain thickness, width and smooth surface. The characteristics are high output and good quality, but the process equipment is complex and the investment is large.

Typical applications: water supply pipes, household pipes, house wall panels, commercial machine casings, electronic product packaging, medical equipment, food packaging, etc.

Injection molding process conditions:

Drying treatment: usually does not require drying.

Melting temperature: 185 ~ 205 degrees Celsius. Mold temperature: 20~50 degrees Celsius

Injection pressure: up to 1500 × 105Pa, holding pressure: can be as large as 1000 × 105Pa.

Injection rate: To avoid material degradation, a comparable injection rate is generally used.

Runners and gates: All regular gates can be used. If you are working with smaller parts, it is best to use tip-type gates or submerged gates; for thicker parts, it is best to use fan-shaped gates. The minimum diameter of the tip gate or submerged gate shall be 1 mm; the thickness of the fan gate shall not be less than 1 mm.

Chemical and physical properties: Rigid PVC is one of the most widely used plastic materials. It is a non-crystalline material. Stabilizers, lubricants, auxiliary processing agents, colorants, impact agents and other additives are often added in actual use. It has non-flammability, high strength, weather resistance and excellent geometric stability. PVC is highly resistant to oxidizing agents, reducing agents and strong acids. However, it can be corroded by concentrated oxidizing acids such as concentrated sulfuric acid, concentrated nitric acid and is also unsuitable for use with aromatic hydrocarbons. Where chlorinated hydrocarbons are in contact. The melting temperature of PVC during processing is a very important process parameter. If this parameter is improper, it will lead to the problem of material decomposition. The flow characteristics of PVC are quite poor and the process range is narrow. In particular, large molecular weight PVC materials are more difficult to process (this material usually incorporates a lubricant to improve flow characteristics), so small molecular weight PVC materials are usually used. The shrinkage rate of PVC is quite low, generally 0.2% to 0.6%.

The design points of the formula are: PVC resin generally uses type 2, and polymerization degree is 1300 or more. Thus, the strength and elongation are higher. Type 3 resins are sometimes used (degree of polymerization is about 1000).

The total amount of plasticizer is critical, depending on the user's requirements for film hardness. Generally, it is 45~52 parts, the industrial film can be less, so the strength is higher, the plastic film plasticizer can be more, so the softness is better.

Plasticizers commonly use dioctyl phthalate (DOP). Coupled with some other varieties of plasticizers, mutual complement each other. If epoxy plasticizer is used, weather resistance and low temperature resistance can be improved. The use of M-50 plasticizer can reduce the material cost, the stabilizer is mostly made of metal soap, and the transparency is good. Lead salt stabilizers are available for the production of opaque films. The dosage is 2~4 parts. The amount of lubricant is about 1 part, which affects the secondary processing properties (printing, welding, etc.) of the film when it is too much.

An antioxidant, an ultraviolet ray inhibitor, a modifier, etc. may be added as needed according to the user's request. The dosage is 0.3~1 part. Some plasticizers such as DOA cannot be used in toys and food packaging films because they are toxic.

According to GB 3830-1983 standard; PVC rolled products are divided into 0.25mm or more sheets, 0.25mm or less film and plasticizers with 0 to 5 parts of plasticizer, 6~25 parts of semi-hard products and 25 or more. Soft product.