Unit 2 - Combining Materials

Question 1

Name the four main ways of combining materials

Answer 1

• Cast extrusion
• Blown extrusion
• Lamination
• Metallisation

Question 2

Describe how films are metallised

Answer 2

• The deposition of a very thin layer of aluminium onto a film surface in a thickness of around 0.05µm
• Achieved by vacuum deposition of aluminium vapour into a substrate in a batch process
• Usually not completely continuous on an atomic level as it is only a few atoms thick

Question 3

Give 3 advantges of metallising film

Answer 3

• Improved barrier to moisture and gas
• Improved barrier to light
• Shiny metallic appearance without the need for foil

Question 4

Why were retort pouches developed?

Answer 4

Designed to withstand sterilisation to allow microbiologically-sensitive products such as pet food to be packed

Question 5

Name the four materials used in retort pouches

Answer 5

Usually PET, nylon, foil, and PP-based

Question 6

When is SiOx used in a retort pouch?

Answer 6

If there is a window or if it is microwaveable