Travel squeeze bottle

A flexible LDPE bottle lets you squeeze out a small amount of shampoo or lotion.

Travel squeeze bottle, illustrative image

Material

Squeezable bottle body: LDPE

Material selection rationale

Flexible walls
Deform under finger pressure to dispense the contents.
Low water uptake
The bottle wall remains a separate barrier around the liquid.
Wall recovery
A relatively flexible thin wall deforms under a squeeze; the cap opening and air return influence how the bottle dispenses and recovers.

How it becomes a product

  1. Blow-mould the body: An extruded tube of LDPE is inflated against a bottle mould. The hot tube is inflated and cooled, keeping sufficient material at the neck while allowing the body to remain squeezable.
  2. Trim and assemble: The body is cooled and trimmed before a separately made cap is attached.

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. LDPE dispensing bottle for travel toiletriesNalgene
  2. Poly(ethene): structure, manufacture and usesChemical Industry Education Centre, University of York