Polythene Bag Manufacturing Process

Plastic bags have many benefits, including being fully customisable, and are an ideal way to display your company’s branding.  We manufacture only the highest quality plastic bags for a range of industries, with quick lead times.  Whatever your requirements, we can produce custom plastic bags in bulk, to your specifications.

On this page, we explain how plastic bags are made, from producing the rolls of plastic film, to printing and cutting the individual bags.

Blending and Mixing Resins

The first stage of the process is to chemically change propane gas into an ethylene monomer in a furnace.  The monomer is polymerised in a high-pressure reactor, resulting in the production of low-density polyethylene (LDPE).  The LDPE is then compounded with additives while still in its molten state.  The final product produced is clear plastic resin in pellet form, which is transferred to silos for storage.  A multitude of colours can be added at a later stage, to create custom plastic bags that match your branding.

Extruding Plastic Film

Once the resin pellets have been mixed to create the desired custom product, they are fed though extruders, which melts the material.  The melted plastic is then forced through a circular die, where air is added through the centre to form a tube.  Cool air is also blown onto the outside of the tube to cool the plastic and help form its shape.  The tube is then wound up into rolls of plastic film, which are removed from the machine, and samples are taken to check for size and accuracy.

Converting Film to Bags

The next stage of the process is printing brand designs onto the plastic film.  Plastic bags are an ideal way to reinforce your brand messaging with customers and potential customers, and we can produce designs that meet your specifications.

Impressions are made on the film, using inking rollers.  When the printing process is complete, the plastic film is wrapped up again ready for cutting.  Converting then takes place to produce individual bags from the single roll.  A sealer is used to bond the sides of the bag together using heat.  Other types of customisations are available during the converting process, such as handle punching, ziplocking, header sealing and creating perforations, depending on your requirements.

Once the film has been successfully converted to custom plastic bags, the bags are carefully packed in preparation for shipment.

To find out more about the different types of bags we can produce for you, take a look at our carrier bags page.

Whatever your polythene bag manufacturing needs, we can help.  Contact us today for a quote tailored to your requirements.

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