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
polythene suppliers Bags
polythene suppliers bags in the 8 x 10 size can cause more trouble than their simple appearance recommends, because a small fault in gauge, fit or sealing soon turns into slow packing and avoidable rejects. The film requirements enough strength to take rough handling and sharp edges, yet it still has to open cleanly at the bench and sit neatly on the product without wasting material. If the maker lets the gauge drift or the melt flow vary, the result is often twisted mouths, weak seams or bags that split amid secondary packing. Good control at the converting stage retains the format proper, cuts handling damage and makes the all line easier to dash.
Plastic bags are often treated as a small shopping item, nevertheless the numbers behind them display how fast waste builds up when they are given away without view. A bag that seems harmless at the till becomes a big disposal problem once millions are used each day, particularly if the material is thin and only suited to one trip. Charging for bags changes shopper behaviour fast because it puts a cost on an item previously taken for granted. That kind of policy can cut usage sharply, and the proper lesson is that a modest shift at point of sale can remove a big offer of unnecessary plastic from the waste stream.
~ packaging manufacturers suppliers Bags | polythene suppliers Bags
polythene suppliers bags stay in use because the proper film specification can solve handling problems that other formats merely shift elsewhere. A thin sack manufactured from the gross grade will split at the first awkward corner, while a properly gauged bag can cope with puncture risk, seal pressure and the rough treatment that comes with palletising and re-handling. That balance matters in warehouses where all additional gramme adds to the load across a picking dash, and where poor film control soon shows up as torn sacks, messy secondary packing and waste on the floor or in transit. When the conversion is tight, the bag does its job quietly and the operation carries less damage.
Plastic bags become a problem fast when they are light enough to blow from a trolley, a skip or a bin and stop up in the open air. Once loose, they snag on fencing, drains and stock pallets, then smash down into litter that is hard to recover and even harder to sort. From a packaging point of view, the issue is not only the bag itself nevertheless poor control at handover, disposal and secondary packing. Stronger stock discipline, better bundling and tighter waste handling reduce the chance of bags escaping the site. That saves cleaning time and retains the yard from becoming a origin of nuisance.
polythene suppliers bags are judged less by their label than by how they behave on the floor, because gauge, grade and film structure determine whether a packing line runs cleanly or turns fussy. A stiffer high-density bag retains its shape better for tidy presentation and easier stacking, while a softer low-density bag is more forgiving around strange-shaped stock nevertheless can cling, slow down picking and make sorting harder once waste comes back through the system. The proper trade-off sits between handling speed and material control, so tighter specifications and lighter weights often make sense when loose film requirements to be kept down. A well-chosen bag saves time in packing, storage and disposal, which is why the starting point should be how it performs in use, not only how cost-effective it sees on the order line.
Plastic Bags Bulk: packaging suppliers
Open-top plastic bags need to be chosen for the job, not only for the lowest quoted price. A lighter gauge may see efficient, nevertheless if the bag splits on filling, slips amid select-face handling, or tears in transit, the proper cost ends up higher through spoilage, complaints, and additional labour. Bag width, film strength, and opening behaviour all matter when packing lines are moving fast, particularly where repeated hand loading is involved. Clear specification prevents wasted stock and avoids the normal problem of buying bags that see similar nevertheless perform very differently on the shop floor.
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
