PVC plastic's characteristics and usage
1. PVC (polyvinyl chloride) chemical and physical properties
Rigid PVC is to use one of the most common plastic materials.PVC material is a kind of an amorphous plastics.Often attend stabilizer smooth agent, auxiliary processing agent, pigment, impact resistant agent and other additives in PVC materials.
PVC materials have no flammability, high strength, resistance to climate change and the good geometric stability.PVC of oxidant and recovery agent and acid has very strong to resist force.But it can be strong oxidizing acid such as sulfuric acid, nitric acid corrosion and also shall not apply to the contact with the aromatic hydrocarbons, chlorinated hydrocarbons.
PVC in processing the condensation temperature is a very important process parameters, if the parameter improper will incur material synthesis problems.Activity characteristics of PVC is rather poor, its technological range is very narrow.Especially big molecular weight of PVC material is more difficult to machining (smooth agent improvement activities usually take the material characteristics), so they usually used are small molecular weight of PVC material.PVC shrinkage rate is low, the average was 0.2 ~ 0.6%.
The process conditions of injection moulds
Boring disposal: usually don't demand boring disposition. Condensation temperature: 185 ~ 205 ℃ mold temperature: 20 ~ 50 ℃
Injection pressure: can be big to 1500 bar, bartender pressure: big to 1000 bar,
injection speed: to prevent material degradation, common use reasonably the injection speed.
Runner and gate: all regular gate to use.If processing small parts, had better use the needle type gate or dive into the gate;About thicker parts, it is better to use the fan gate.Pinpoint gate or dive into the gate of minimum diameter should be 1 mm;The thickness of the fan gate cannot be less than 1 mm.