Plastic bags
What is a plastic bag?
There are two answers to this question. The first one is simple - it is a bag made out of plastic. But not only did you know that already, but it only goes a fraction of the way to actually answering the question.
Plastic bags are often referred to as polythene bags, or polybags. These terms, used to mean the same thing, are all perfectly fine, although the term ‘polyethylene’ bag is more accurate. Most plastic bags these days are made from polyethylene, more commonly known as polythene.
Plastic bags come in all shapes and sizes and cover a multitude of uses, from the trusty old carrier bag that helps millions of people take their shopping home to the specialist waste sacks required by hospitals or people dealing with hazardous waste.
Not to mention all of the bags in between!
Packing bags, waste sacks, bubble bags, anti-static bags, minigrip bags, mailing Bags, postal sacks, waste sacks, black sacks, dustbin bags, bin liners, zip seal bags, recycling bags, biodegradable bags, specialist bags, high tensile strength bags and PolyMax extra strong bags - there’s a lot of polythene bags out there!
How are plastic bags made?
Plastic bags are made from polyethylene, with three particular types of polythene - each of varying densities - widely used for manufacturing bags: low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE) and high-density polyethylene (HDPE).
The exact process of making a plastic bag will vary according to the type of plastic bag in question, the density of the polyethylene and the characteristics that the particular bag will require.
However, there are a few common factors used across the manufacturing of each type of bag. Polythene bags are widely created using a method called ‘blown film extrusion’, also known as the ‘tubular film process’.
The ethylene polymer resin used to create the bags comes in the form of pellets. These pellets are placed into a hopper and melted before being extruded to form a thin tube by forcing cool air into the tube, usually vertically from the bottom of the tube.
Once the tube reaches the correct size and the plastic has reached far enough up the cooling tower and cooled properly, it is taken away and flattened.
At this stage the tube can either be split into two halves, with each side used as a flat sheet of film, or the two sides of the tube can be sealed across the width of the film, before being cut and/or perforated to make plastic bags.
Types of plastic bag
If you say ‘plastic bag’ most people think of a standard carrier bag. However, there are many different types of plastic bag. Here are just a few:
Clear plastic bag - standard plastic bag made of clear or opaque polythene
Coloured plastic bag - standard plastic bag made of coloured polythene
Plain plastic bag - standard plastic bag (clear or coloured) containing no markings
Printed plastic bag - plastic bag printed with a name, logo, design etc.
Carrier bags - the classic traditional shopping bag, available with vest, cut, loop, clip close or grip seal handle styles
Gusseted bags - plastic bags with expandable sides (gusset) and a fitted bottom
Self seal bags - simple plastic seal clicks shut and pulls open to use time and time again (also known as grip seal bags or mini grip bags)
Zip lock bags - plastic bags with a zip seal used to open or close the bag
Drawstring bags - plastic bag with a drawstring at the top that fastens to close the bag
Merchandise bags - premium plastic bags printed with a company logo, slogan or design. Ideal for presentation.
Layflat tubing - cut this poly tubing to size and heat seal for your own made-to-measure bags. Perfect for packaging awkwardly shaped or difficult-to-wrap items.
Bags on roll - a roll of bags, wrapped around a central core, each attached to the next by perforation. Easily detaches with a simple tug
Where can I buy plastic bags?
Manufacturers and suppliers of plastic bags include:
Polybags Bulk Sales
Polybags Bulk Sales provides a low cost bespoke manufacturing service for large volume UK polythene users and packaging businesses. Orders placed directly with the manufacturers.
www.polybagsbulksales.co.uk
Polythene-Bags
Polythene-Bags.co.uk specialises in polythene bags with a range that includes mailing bags, waste sacks, display bags and more. With over half a century experience providing polythene packaging we're sure you will find the very best in polythene and polypropylene products.
www.polythene-bags.co.uk
Buy Plastic Bags
A brilliant resource if you want to buy plastic bags, with the ability to order online direct from the supplier. Contains loads of information on the different types of plastic bags available to buy, how plastic bags are made, how to promote your brand with printed plastic bags and much more.
www.buyplasticbags.co.uk
Buy Polythene Bags
BuyPolytheneBags.co.uk offers an extensive guide to polythene bags. With loads of information about all types of plastic packaging, from self-seal bags to antistatic bags to eco-friendly ones. Order direct from the manufacturers at low prices and with free delivery across the UK.
www.buypolythenebags.co.uk
Polybags Ireland
Online retailer of poly bags and polythene packaging offering the Irish the chance to save an extra 21% of all packaging products range.
www.polybags.ie
Polythene Bags
Dedicated division of a major UK packaging supplier and manufacturer, devoted to polythene bags. Working with polythene bags for over 50 years and now offering an increasing range of environmentally friendly products across the packaging spectrum.
www.polythenebags.co
Discount Polybag
International distributor of polythene packaging. Discount Polybag work direct with the manufacturer and can therefore extrude polyethylene film and make polythene bags to suit any order at a price that is right for you.
www.discountpolybag.co.uk
Polythene Bags
Polythene bags and plastic carrier bags specialist providing information about polythene bags, packaging and manufactured bags. All polythene packaging available direct from the manufacturers at low prices that don't compromise the quality.
www.polythenebags.eu
Discount Plastic Bags
Lists discount suppliers of shopping bags, polythene carrier bags and clear plastic bags. Discover how plastic bags are made, the differences between low and high density polythene and what eco-friendly options are available.
www.discountplasticbags.co.uk
Cheap Plastic Bags
Cheap plastic Bags has loads of information on plastic bags with useful links for you to buy quality products at great prices. Find out more about clear plastic bags, heavy duty plastic bags, resealable plastic bags, biodegradable plastic bags and more on this helpful website.
www.cheapplasticbags.co.uk
Research & Resources
For loads more detailed information about plastic bags, from the start of the production process right through to recycling, including details of the different types of plastic bags available, please visit:
Plastic Bags
A free online directory specialising in polythene packaging. Find great websites with lots of information on plastic bags and post your own product listings for free.
www.plasticbags.uk.com
Packaging Knowledge
This online magazine contains in-depth news and information on the world of packaging. Read articles and features and fact sheets about a variety of plastic bags.
www.packagingknowledge.com
Goldstork
Very useful "pick of the web" directory containing lots of interesting, off-beat and unusual websites. Goldstork also offers a vault with only selected hand-picked websites specialising in plastic bags.
www.goldstork.com
Notes on Plastic Bags
~ packaging manufacturers suppliers Bags | polythene suppliers Bags
polythene suppliers bags stay popular because they give predictable handling, and that matters when sacks need to transport cleanly through packing, storage, and despatch without tearing at the seams. A film that is also thin can split below rough treatment, while a heavier gauge gives better resistance nevertheless adds cost and bulk. Tinted polythene suppliers bags are often chosen when products need a bit of privacy, colour coding, or simpler identification in a busy stock area, because the shade assists staff select the proper pack fast. Compostable sacks may suit certain waste streams, nevertheless they behave differently in moisture, heat, and long storage, so material selection requirements to match the job rather than the label. The proper bag is the one that stands up to the handling it will in reality face.
California will soon be the first state in US to ban plastic bags
Plastic bags are a simple part of packaging, nevertheless their behaviour after use makes them a serious nuisance if they are chosen carelessly. Thin polythene suppliers bags are light enough to blow out of skips, cling to fences, and block sorting lines, which is why poor disposal causes so much trouble around warehouses, shopping parks, and roadsides. Even in the supply chain, the gross bag gauge can mean tearing at the sealing jaw, split handles, or loads that shed loose items amid transit. Better control beginnings with matching the bag to the task, utilising the proper film thickness and collecting used film for proper recycling rather than treating it as waste. That is the contrast between a tidy consumable and a mess that retains coming back.
A blanket ban on polythene suppliers bags changes above a checkout routine, because it affects sourcing, packing methods, and the method loose products transport through a supply chain. Where a simple carrier used to be pulled from a box and filled in seconds, a prohibited item forces a switch to paper, board, reusable cases, or thicker multiple-use films that behave differently in handling and storage. That means new space on the line, fresh checks on bag size and strength, and closer attention to what happens to returns and damaged products. Transport also becomes less forgiving if replacement packs are less flexible or less moisture-resistant. The proper test is whether the all operation can retain moving without creating additional waste or handling damage.
Are plastic bags getting a inferior rap?
Comparing plastic bags with paper bags only makes sense when the full production chain is considered, not only the headline material. A dash of 1,000 plastic bags may use far less raw material by weight, nevertheless the film still has to be extruded, slit, printed if needed, and sealed with tight gauge control so the bags do not split at the seams. Paper bags need heavier board, more fibre, more converting steps, and often stronger secondary packing to stop scuffing and moisture damage in transit. The proper issue is not a simple green badge; it is which pack performs the job with less faults, less waste, and less handling trouble through dispatch and shopping use.
polythene suppliers Bags
polythene suppliers bags in the 12" x 18" size are chosen because they sit in a useful middle ground between small pack items and larger loose contents. That format gives enough depth for products, paperwork, or bundled parts without wasting material on oversised packaging, which assists retain film usage down and storage neater. The gauge matters as much as the size, because a thin bag may suit light secondary packing, while a heavier gauge gives better puncture resistance and less risk of splitting amid filling or transit. When the bag matches the load properly, handling damage drops and stock transports through the warehouse more cleanly. A sensible size and strength selection saves trouble later.
A tightly packed consignment of carrier bags, brought back to the retailer for exchange, speaks less to a simple giveaway than to the mechanics of mail-consumer recovery at store level. When polythene suppliers is kept broadly mono-material and clean of food residue, it retains enough integrity for downstream sorting; the practical constraint is not sentiment nevertheless volumetric efficiency, because loose film eats into backroom stock space and complicates handling. Compacting the material into a dense bundle improves tote stability, reduces tare weight in return transport, and makes the assortment workable at the select-face. The reusable bag offered in exchange sits within the same logic: a more heavy-duty article with longer service life, lower amortised energy per use, and a clearer route to repeat circulation than a stream of lightweight secondary bags that are awkward to store, prone to snagging, and often downgraded before they reach any meaningful recycling stream.
Recycling and reusing plastic bags
A 2005 study by the Waste & Resources Action Programme (WRAP), cited by the Environment Agency in their 2011 report ‘Life Cycle Assessment of Supermarket Carrier Bags’, reported on how traditional lightweight ‘single use’ carrier bags were used after their initial intended use.
Their survey found that 89% of respondents reused at least some carrier bags. 59% of people said they reused all carrier bags, while 16% reused most of them, 7% reused around half and 7% reused some. Overall, it was estimated that 76% of carrier bags were reused.
The report also included details of how people reuse their carrier bags. The results can be found in the table below.
The reuse of lightweight carrier bags (WRAP 2005 survey)
| Reuse applications | % of respondents |
| Bin liner in kitchen | 53% |
| Put rubbish into it then throw it away | 43% |
| Bin liner in other rooms | 26% |
| Store things at home | 14% |
| Dog / cat / pet mess | 11% |
| Reuse for other shopping | 10% |
| Reuse for supermarket shopping | 8% |
| Packed lunches | 8% |
| Carry other things in when going out | 4% |
| Garden refuse | 1% |
| Give to charity shops | 1% |
| Put football boots / wellies in | 1% |
| Keep bottles / cans in for recycling | 1% |
| Other uses | 2% |
| Do not have a use / discard | 11% |
Source: Environment Agency - Life Cycle Assessment of Supermarket Carrier Bags
