Protective foam wrap

LDPE foam wraps around fragile objects as a light cushioning layer.

Protective foam wrap, illustrative image

Material

Thin polyethylene foam sheet: LDPE

Material selection rationale

Cellular structure
Small gas-filled cells let the sheet compress.
Flexibility
A thin sheet bends around an object's surface.
Cushion travel
A foam sheet needs space to compress. A layer that is too thin or already crushed cannot provide the same protective travel.

How it becomes a product

  1. Extrude and foam: LDPE compound expands into a cellular sheet during controlled foaming. Extrusion and cooling control the expanded sheet’s thickness and cell structure before it is slit and rolled.
  2. Cool and roll: The sheet is cooled, slit and wound into rolls.

Preparation routes

Ethene route

Free-radical addition polymerisation. Ethene molecules join into long chains. The high-pressure radical process also creates branches, giving the material its characteristic low-density structure. Branch formation during radical growth changes packing without adding a different main-chain repeat unit. This connects reaction conditions to film flexibility.

A radical initiator, such as an organic peroxide, starts chain growth. It is not a second monomer. Film blowing, heat sealing and foam expansion happen after the chemical chains have formed.

  1. Poly(ethene): structure, manufacture and usesChemical Industry Education Centre, University of York

Sources

  1. Cell-Aire low-density polyethylene protective foamSealed Air
  2. Poly(ethene): structure, manufacture and usesChemical Industry Education Centre, University of York
  3. Reference document on best available techniques in the production of polymersEuropean Commission, Joint Research Centre · 2007