Category Archives: Polythene News

What are we doing for the environment and what can we help you to do?

What are we doing for the environment and what can we help you to do?

STM Packaging Group recycles all of its process and office waste (and always has done!)

Our own process waste polythene, plus material returned from our customers, local companies, and individuals goes to a specialist reprocessor, Chase Plastics, a key partner to our Group. They reprocess the clear and mixed coloured waste separately and return the recycled polymer granules to us. Due to Chase Plastic’s unique double clean process, this material is returned with very low odour levels. We then make new products with those polymer granules – recycled clear bagsgrey mailers and tube film for lots of suitable applications.

We also recycle all of our waste boxes and office paper through the usual paper recycling channels. In addition, we donate our broken pallets, waste reel cores, and any other wood waste to members of our staff with multi fuel burners to generate free and carbon neutral heat for their homes.

“But how can polythene be a good option?”

All polythene (LDPE) is recyclable. This is a key question we are being asked by customers and end users alike. To help to explain this, we have advanced plans in place to add a ‘recyclable’ or ‘recycled’ message to all of our stock mailing bags to increase public awareness and to help improve recycling levels of the product from the domestic environment. We can also offer a wide range of recycled films. Please ask one of our expert advisors if this is of interest to you and your customers.

To recycle all of your polythene products, you can return it to STM Packaging for reprocessing. If this is not convenient, you can put all polythene products into the supermarket carrier bag recycling stations and they will recycle them for you.

carrier bag recycling stations

reduce reuse recycle symbolAn exciting new project!

STM Packaging is working on a new project – we are trialling a film made from corn starch which is 100% biodegradable – we will let you know as soon as this product is available!

We believe it is great to see so many new initiatives being developed to address the effects of plastics in the environment. One eye-catching scheme in the media recently was RPC bpi, a leading plastics company, recycling very low grade polythene waste into polymer granules to be used in road building. What a fabulous use of the material where it can never litter or get into the wider environment while saving the natural resources of making bitumen.

If you have any further questions for us on this hot topic, please don’t be shy – ask us, and we are sure we can help to assure you and your supply chain of the credentials of using an ethical polythene company!

daisy and splatter printed mailing bags

New Daisy and Splatter designs are here!

We’ve added two new designs to our growing divinely different® printed mailing bags range – Daisy and Splatter!

Here at Shirlplass we recognise just how popular our divinely different®  printed mailing bags are for our customers that want to make an impact with their packaging but don’t want the additional cost of custom bags. We loved both of these designs so much that we decided to release both at once!


Our retro Daisy design is guaranteed to catch the eye. We designed
this in four different colour variants so you can mix and match.

green daisy printed mailing bags
green daisy printed mailing bags
green daisy printed mailing bags
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Our Splatter design comes in two colours – blue and black. This bold design is sure to grab attention!

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With our new designs you can expect the same great quality as our other products. Each bag is sure to have the following:

  • A strong, permanent ‘peel and seal’ adhesive flap.
  • Super tough side seams, manufactured using 50micron co-extruded film.
  • Opaque and weatherproof so the contents stay safe and secure.
  • Eye-catching designs in vibrant colours.
  • A blank address area suitable for pen or labels.

Our Daisy and Splatter mailing bags are available in the most popular mailing bag sizes:

  • 162mm x 230mm + 40mm lip for your C5 sized items
  • 250mm x 350mm + 40mm lip for your C4 or slightly oversized C4 items
  • 330mm x 440mm + 40mm lip for C3 sizes items.

Please don’t hesitate to contact our experienced sales team today to discuss products or to place an order for next day delivery.

Three images in one showing a bottom weld machine and finished bag samples

Bottom Weld Polythene Bags Explained

What is a bottom weld polythene bag?

Machine image of our in-house bottomweld machine producing a blue polybag
A bottom weld polythene bag is simply a polythene sack. It is made from a flattened polythene tube, this type of film is referred to as LFT in the industry. This tube is then passed through a machine which is sealed by a heated bar after a certain length of film has been passed through it i.e. the length of your bag. The bag is then cut from the remaining tube two to five millimetres after the seal. This type of bag can’t have tape or glue but if you heat seal the top of your bag as well, you’ll have yourself an air tight bag.

Benefits of bottom weld polythene bags

The biggest benefit of these bags is the potential size they can be made to. As the machine seals at the bottom you can feed as much polythene film through as you like before the seal. This means that the length of your polythene bag can be huge. So far we’ve made bags with lengths going up to 2.5mtr. There is a minimum draw of 100mm that you should be aware of however.

Another benefit is the strength of the bag. The heated bar leaves a 2mm seal at the bottom of the bag which in turn allows it to hold a lot of weight, we can even produce a double weld bag for extra strength.

A further significant benefit of this type of bag is the fact that we can run two or three polythene reels at once, reducing our conversion time and making our delivery date to you much faster.

Who are bottom weld bags useful to?

Bottom weld bags are ideal for a vast range of things including pet food, bedding, industrial wipes, building supplies, pharmaceuticals, or anything that needs protection from the elements. Let’s not forget the film can also be printed beforehand so if you need your company logo, some warning text, or a custom message then we can provide that. We currently print up to 8 colours. For more details on printing to polythene film check out our printed mailing bags.

If you need any more information regarding any of the above, or you would like a quote, please get in touch with our friendly team who will be happy to help.


Shirlplass polythene packaging

Protecting your products with polythene

Why choose polythene for your packaging needs?

Polythene is one of the most versatile products in the world of packaging and as a result has revolutionised the way we package and protect our goods. The development of better materials has allowed us to provide protection for your goods. Whether you are looking to transfer pallets during transit, keeping goods in a warehouse or sending items in the post, we have a packaging solution. Using polythene can make sure your goods arrive in one place safely whilst providing a cost-effective solution compared to boxes and paper envelopes.

High Strength & Durability

The strength of polythene is what makes it such an important material. Due to its properties of high strength, durability and versatility it means there is a product to protect most goods, regardless of the shape and size.

Polythene wrapped pallet


Due to polythene being waterproof you can be assured that however bad the weather your customers will receive their products without any water damage. Alternatives such as paper envelopes and cardboard boxes will not protect against excessive moisture, as a result water can disintegrate the packaging and potentially damage the products inside.

Grey poythene mailing bags

Rip Resistant

One of the main concerns when sending goods out in the post or with a courier is what condition they will arrive with the recipient. Occasionally items sent out in boxes will have ripped sides with the contents of the box missing. However, unlike paper, polythene is rip resistant and won’t tear easily. This means that when sending out products the polythene bags can be miss-treated and still securely hold the contents inside.

Crushed delivery box

Please click on the link to watch a short video demonstrating the tear resistant properties:

Tamper Evident

Most our poly postal envelopes and mailing bags feature a permanent tamper proof peel and seal glue strip as standard. This creates a secure seal to ship a wide range of valuable products and documents safe in knowledge that you can tell if the envelopes have been opened.

co-extruded polythene mailing bags glue strip

Contact us today to find out how Shirlplass can help you find the right packaging for your needs.



Polythene film reels

Why Choose Polythene

Polythene is an incredibly versatile material and it’s used all over the world as a protective product, wrapper or container.

The impending 5p charge for supermarket carrier bags has fuelled the publicity surrounding the use of polythene and its environmental impacts. We want to show you the benefits of polythene and why you should choose it.

The Environment:
  • When disposed of correctly it can be easily recycled and made into a wide range of other products.
  • Polythene is made using a by-product of the oil refining process, and uses less energy than paper to convert the raw polymer pellets into a usable form.
  • The recycling process is also low on energy use as polythene only needs to be melted and reformed.
  • Paper is a common alternative to polythene. The use of paper is not the environmental solution that many people think it is. It is estimated that to create 1 ton of copier paper using the Kraft pulping process around 24 trees are required*.
  • Similar figures could be used to estimate the amount of trees required for the manufacture of paper envelopes.
  • In addition to the amount of raw material, there’s also a significant amount of energy and chemicals required in the manufacturing process of paper and also recycled paper.

When choosing between using paper packaging and polythene packaging, consider the source of the raw material, the energy required to produce it and the ease of which it can be recycled – it’s easy to see why polythene is such a popular choice!

We are very environmentally conscious and we know that many of our customer are too, for further information visit our environment page.

Quality and durability:

As well as the environmental impact there are also other things to consider, such as quality and durability. Research and development of improved polythene materials allows us to provide protection whether you are looking to keep goods in a warehouse, transferring pallets during transit or posting small items direct to customers. Polythene will ensure your goods arrive safely whilst providing a cost effective solution when compared to paper envelopes and boxes.

Durability and High Strength: Polythene’s properties of high strength, versatility and durability makes it the ideal material to use when protecting most goods, regardless of size or shape.

Waterproof: With polythene you can be assured that however bad the weather your customers will receive their products without any water damage. Common alternatives to polythene, such as cardboard boxes and paper envelopes, do not protect against excessive moisture, as a result water can disintegrate the packaging and potentially damage the products.

Rip Resistance: A major concern when despatching goods with a courier or sending in the post is the quality of the packaging and the condition they will arrive when delivered. Sometimes items sent out in boxes can have damaged sides with some of the contents of the box missing. However, unlike paper, polythene is rip resistant and won’t tear easily, this means that when sending out products the packaging will still securely hold the contents.

Tamper Evident: Most of our mailing bags and envelopes feature a permanent tamper proof peel and seal strip. This creates a secure seal to send a wide range of valuable products and documents safe in knowledge that you can tell if the envelope has been opened or tampered with.

Contact us today to find out how we can help you find the right polythene packaging for your products.

Mailing bag size guide measurements

Mailing Bag Size Guide

Due to the different shapes, sizes and varieties of items being packed, it’s easy to become confused when choosing the right mailing bag size for your needs!

Mailing Bag Size Guide 2We all know that Mailing Bags have become one of the most important items of packaging for retailers. However, due to the different shapes, sizes and varieties of items being packed, it is easy to become confused when choosing the right sized mailing bag.

Therefore we thought we would create a size guide to help you decide on what mailing bag size is right for your needs.

We have tried and tested all of these items and they all fit in the mailing bags suggested. However always measure the size of the item first, that way you will always get the right size.

Here at Sefton Transmail we continue to review the sizes we provide from stock to ensure we can always provide a great range of options. This means that whether you are packing a mobile phone cover, DVD’s or even an A1 flip-chart pad, we have a mailing bag to suit your requirements.

All of these sizes are available in our grey made again range, with the most popular sizes available in our Spectrum coloured mailing bag range and our new Divinely Different range.

If you are still unsure what is the best size contact us today, our team of experts can help you find the right solution.