How to make PVC softer?

1. Add plasticizer (most commonly used method)

Common plasticizer types:

An example is DOP (dioctyl phthalate) and DINP (diisononyl phthalate) for low cost, however, they come with an asterisk for environmental and health concerns. Phthalic acid esters. ESO along with ATBC citric acid ester are an example of environmentally friendly plasticizers and are deemed acceptable for food contact or medical usage. Polymeric plasticizers such as polyesters have good migration resistance making them suitable for long term use.

Addition ratio:

The amount of plasticizer added is generally 30%~70% of PVC resin. The higher the ratio, the softer the material.

For example: the plasticizer content of hard PVC is about 10%, and the soft PVC can reach more than 50%.

2. Softening by heating (temporary method)

By heating, the activity of PVC molecular chains is enhanced and they become temporarily soft (they may return to their original state after cooling):

Applicable scenarios: Repair hardened PVC products (such as water pipes and tablecloths).

Operation steps:

Use a hair dryer or a hot air gun to evenly heat the PVC surface to 60~80℃ (avoid exceeding 100℃ to prevent decomposition).

Stretch or shape while hot, and shape after cooling.

3. Adjust processing temperature

During the production or processing of PVC, controlling temperature can affect softness:

Plasticizing temperature: sheath temperature for the extrusion or injection molding should be lowered appropriately (i.e. 180 degrees centigrade should become 160 degrees centigrade) in order to ease excessive molecular chain entanglements while improving softness.

Cooling speed: toughening of the material is strengtheded when the cooling rate is slowed down, so that the molecular chains are able to relax.