Food packaging – Common materials

PP(Polypropylene)

Characteristic :

PP has high mechanical strength (tear and tensile strength), quite strong. Because it is not as flexible as PE and difficult to stretch, it is made into yarn. Especially the ability to tear easily when there is a small cut or puncture.

Transparent, high surface gloss for high printability, clear print.

Withstands temperatures higher than 100oC. However, the sealing temperature (body) of PP packaging (140oC) – higher than PE – can cause melting and damage to the external structural laminate. Therefore, PP is rarely used as the innermost layer.

Has the property of repelling O2, steam, grease, and other gases

Uses:

Used as a single-layer packaging for food preservation, which does not require strict anti-oxidation.

Forming yarn, weaving into packaging for food and grain in bulk.

PP is also produced as a cover film for multi-layer films to increase air permeability,

PE (Polyethylene):

Characteristic:

Transparent, slightly translucent, with a glossy, flexible surface.

Quickly absorb water and steam well.

Waterproof to O2, CO2, N2, and grease is poor.

Withstand high temperatures (below 230oC) for a short time.

Being inflated and damaged when in contact with aromatic oils or detergents such as Alcohol, acetone, H2O2 ...

Gases and flavors can penetrate through, so PE can also absorb and retain odors in the packaging itself, and this same smell can be absorbed by the food contained, causing a loss of sensory value. of the product.

Uses:

– Making bags of all kinds, boxes (cans) with a volume of 1 to 20 liters with different thicknesses.

 

- Manufacture of bottle caps. Because bottle caps absorb odors, food bottles with PE caps must be stored in an odor-free environment.

PET(Polyethylene terephthalate):

Characteristic:

PET is an important type of food packaging that can be filmed or formed into bottles due to the following properties:

- High mechanical strength, able to withstand tear and impact force, high abrasion resistance, and high rigidity.

 

- Inert to the food environment.

 

- Transparent.

 

– O2 and CO2 waterproof better than other plastics.

 

– When heated to 200oC or cooled at -90oC, the chemical structure of the PET circuit remains the same, and the gas and vapor permeability remains unchanged when the temperature is about 1000C