One-way air release range (Lactosac, Flexivent, Labyrinth)

Allow air to escape sacks, without letting it back in, with Flexipol’s one-way air release systems.

Flexipol’s one-way air release system sacks allow the air to escape, without letting it get back in. Lactosac, Flexivent, and Labyrinth are innovative one-way air release systems exclusive to Flexipol.


  • More hygienic than paper sacks
  • Reduces waste packaging vs paper sacks
  • Greatly reduces infestation risk vs paper sacks
  • Inner colour/outer colour can be different
  • Water resistant
  • Suitable for fully or semi-automatic filling lines
  • Material blend designed for purpose
  • Bespoke and tailored to your needs
  • One-way air release systems

Available technologies

  • Flexographic printing

    High quality print in up to 8 colours

  • UVI inhibitors

    Extended protection against sunlight

  • UN approved sacks

    Certified for solid or liquid dangerous materials

  • Inner/outer colours

    Different colour inner and outer material

  • Specification support and advice

    Expertly designed packaging tailored for customer needs

  • EVOH material

    Barrier qualities, especially for pungent or oily ingredients

  • Surface treatments

    Improved adhesion for inks, labels and tapes

  • Flexitac

    Extra protection against slippage during palletisation

  • Film colours

    A vast variety of film colours

  • Anti-slip properties

    Unique film recipe or surface treatment to reduce slip

About our one-way air release system range

Flexipol’s range of one-way air release system sacks allow air to escape the sacks, without letting it get back in.

The three products Flexipol has developed within this innovative range are:
  1. Lactosac: Featuring a one-way air release valve and available in our block bottom design for ease of filling and palletisation. It is also designed to run on paper sack lines, so no new machine investment is needed. Worldwide patent pending.
  2. Flexivent: Available as a block bottom or side weld sack, and features a specialised one-way air release system.
  3. Labyrinth: Available as gusseted layflat tubing or side-gusseted sacks and also features a specialised one-way air release system.
Get in touch for more information

All of our one-way air release sacks are bespoke and manufactured to order. Our technical experts work with customers to calculate a size and thickness perfect for your application and the volume and density of product you would like to pack.