Polyvinyl Chloride (PVC) Injection Molding Process

Typical applications: water supply pipe, household pipe, house wall panel, commercial machine shell, electronic product packaging, medical equipment, food packaging, etc.

 

Chemical and physical properties :

• PVC material is an amorphous material.
• PVC materials are often added to the actual use of stabilizers, lubricants, auxiliary processing agents, colors, impact agents and other additives.
• Non-flammability, high strength, climate resistance and excellent geometric stability.
• PVC has a strong resistance to oxidants, reducing agents and strong acids. However, it can be corroded by concentrated oxidizing acids such as concentrated sulfuric acid, concentrated nitric acid and is not suitable for contact with aromatic hydrocarbons and chlorinated hydrocarbons.
• The melting temperature of PVC is a very important process parameter during processing, and if this parameter is improper, it will lead to the problem of material decomposition.
• The flow characteristics of PVC are quite poor, and its process range is very narrow.

 In particular, large molecular weight PVC materials are more difficult to process (this material is usually added to improve the flow characteristics of lubricants), so small molecular weight PVC materials are usually used.

The shrinkage rate of PVC is quite low, generally 0.2-0.6%.

 

Injection mold process conditions:

Drying treatment: Usually no drying treatment is required.

Melting temperature :185~205℃ Mold temperature :20~50℃. 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 processing smaller parts, it is best to use a pinpoint gate or a submerged gate; For thicker parts, it is best to use a fan gate. The minimum diameter of the pinpoint gate or the submerged gate shall be 1mm; The thickness of the fan gate should not be less than 1mm.

Chemical and physical properties: Rigid PVC is one of the most widely used plastic materials.