Poly Bags 101

Is your business looking to nail its e-commerce bagging needs, ace its retail store order fulfilment process or master its product postage? Then poly bags are your must-have merch! We’ve bagged a Q&A session with Tom Hill, our resident polybag know-it-all to uncover the why's, the what's and the how's behind these unassuming - but all-important - little warehouse staples.

What are poly bags?

These helpful heroes are pockets of flexible LDPE plastic supplied either on a continuous roll or fanfolded into cartons. They are designed to be fed through an automated vertical bagging machine which blows each bag open in turn ready for products to be loaded inside. Once packed, each bag is heat sealed by the machine to close (which also separates the bag from the roll) and the contents within are safely and securely enclosed before the next bag is dispensed. 

Poly bags are designed to pack goods for both display and transit purposes with the design highly customisable for the specific application required.

Fan-folded poly bags in cartons - branded

Fan-folded poly bags in cartons - standard

The largest bag dimensions available from YPS are 600mm wide x 800mm long and the smallest size bag possible is 50mm wide x 50mm long. The lowest thickness (or micron) in our range is 32mu and the maximum is 100mu. Tom recommends keeping to a lower micron specification where possible, as this helps users reduce their overall plastic consumption as well as making the bags more lightweight. Lighter bags improve the reliability of the compressed air opening mechanism used by autobagging machines. However, the required thickness of the bag is primarily dictated by the product and purpose; heavy plumbing parts being delivered to a residential address would obviously need a thicker, more heavy-duty bag than packs of cleaning sponges in a retail store.  

Tom suggests that businesses requiring smaller specifications of bags always opt for reels instead of bags folded into boxes. This is due to the fact that as bag sizes increase, the available space on each core fills up faster. When concertinaed in boxes, the capacity for large bags is much greater than reels, equating to fewer changeovers in production between bag batches and less overall downtime. ‘Realistically the cut-off sizing point for a bag being supplied on a reel is 300mm wide - anything larger than this would be best provided fan-folded in cartons to maximise their longevity in production’ says Tom.  

What are poly bags used for?

Having worked with a very diverse array of industries and sectors throughout his career, Tom has seen autobags used in thousands of packing processes. ‘Typically poly bags are perfect for bagging e-commerce orders, automotive parts, apparel and footwear, hardware, plumbing parts, electrical components, injection moulding parts, pharmaceutical products, crafts and hobby accessories or aerospace parts. However, I’ve seen some more unusual applications too, like jewellery, spectacles and even medical implants!’ shares Tom. 

Because poly bags are an extremely flexible packing option, they lend themselves well to many products, sectors and uses. They can be used to pack products for point-of-sale displays in stores, for keeping together fiddly fixings in flat-packed furniture boxes or for shipping out products in the post. Poly bags also cater for more bespoke needs - for instance, our VCI bags protect items vulnerable to oxidisation and rusting, making them perfect for metal items or items being shipped overseas. Tom estimates that around 80% of the applications we supply bags for at YPS are industrial in nature, with e-commerce a close second (and rising). 

Mailing bags vs poly bags

Our mailers and poly bags are similar in composition except that mailers undergo a co-extrusion process during manufacture to produce a fully opaque bag with a white outer and a black inner lining. ‘This adds security and anonymity to the bagged product inside, ready for the postal network,’ explains Tom. ‘This makes them perfect for confidential materials and prescriptions.’ Mailing bags are also usually supplied in a thicker micron to add integrity to the pack and prevent puncture. 

Standard poly bags, by contrast, can be produced in almost any desired format or design, with see-through windows, transparent panels and a multitude of colours if required. Their typical purpose as retail packs affords them much more freedom of visual appeal than mailers and they are often used to enhance or show off the products within, rather than hide them.  

Mailing Bags

Planet-friendly polybags

All specifications of our poly bags and postal bags (except for VCI) are not only 100% recyclable to LDPE 04, but also contain a plastic packaging tax-evading 30%+ recycled content for a circular economy conforming solution. 

What’s more, all of our bags are suitable for on-bag thermal printing. Without additional stickers, labels and/or adhesive materials being used to add information, the bags maintain a mono-material status and are therefore less challenging for recycling infrastructure to process. 

Tom also highlights the inherent sustainability of poly bags, saying ‘compared to cardboard packaging solutions, bags significantly reduce packaging weights, reduce the consumption of - and need for - void-fill materials and prevent costly unsustainable returns by boosting the packaging’s protectiveness with regards to their waterproof, non-tear qualities.’ In a further boost to their eco credentials, shipping bags can incorporate an optional reclosable strip, allowing customers to repurpose and reuse them if required.

Printed poly bags

‘For businesses looking to level up their packaging, poly bags can be upgraded with custom printed designs which is always a brilliant way to stand out from the crowd’, explains Tom. ‘You can choose to keep it simple with a minimal colour palette, text, a basic logo or a barcode. Or you can go all out with elaborate patterns, QR codes, windows and recycling symbols. For YPS customers, imagination is the only limit.’

Our poly bags - regardless of size or type - can be printed in a range of eight high-definition PMS colours and can incorporate photographic images. Plus, printing on one side, both sides and in or outside the bags is possible. You can rest assured that the vibrancy, sharpness, high resolution, and clarity of our printed bags are totally unrivalled in the industry. 

The process for acquiring custom-printed bags is straightforward; once a design is finalised, customers can supply these to our dedicated account managers in high-resolution vector files. A full-colour PDF proof is created by our manufacturing site before being signed off by the customer. At this point, a true-to-size plate (with minimal tolerances) is made which remains the property of the customer and the bags go into production. With YPS, this is a fast and efficient process incurring minimal lead times.

Special features

LDPE autobags can be supplied with a multitude of clever features to enhance their usability. 

Compartments are one such intelligent possibility, as Tom explains. ‘Vertical seals can be built into each bag, creating a number of different sections within the same pack. This is most useful for applications such as hardware packing, where small components are best kept separate. A powder-coated hinge for instance could not be packed side by side with sharp screws that could scratch its surface. Customers do expect these to come in one handy pack though, so the use of compartments provides convenience as well as pristine products.’ 

A wealth of other features are also on offer. For display in retail applications, bags can benefit from hang holes in a huge scope of sizes and styles. And as already alluded to, e-com mailers can have reclosable strips embedded to facilitate easy and convenient customer returns. Any and all poly bags can be supplied with ‘Ez’™ easy-tear opening perforations and air vents or pin holes that decrease the volume of the bags by expelling air. 

Bag lead times

YPS currently have very competitive stock levels and availability of poly bags and mailers. Standard bags in a range of sizes, specs and thicknesses are ready for next-day delivery across the UK, with more bespoke blends (VCI, ESD, Anti-static, gamma-patient) available with the shortest lead times within the industry. Our 25,000 sq foot warehouse allows us to maintain extensive supplies of material ready for fast shipment, whilst our convenient call-off order facility allows customers to forecast as much as 12 months worth of usage and have us reserve it in our warehouse to despatch in batches as required.

Bag it up

The use of poly bags and mailers in e-commerce, order fulfilment and industrial packing applications is a surefire recipe for success. Lightweight, secure, 100% recyclable, the option for recycled content in the blend, a plethora of useful features and the option for eye-catching printed designs; bags make packing a breeze for busy distribution centres. Designed for use with our selection of vertical bagging units, as well as any bagging unit from Autobag and other key machinery suppliers, a custom bagging solution could be easier than you think with YPS.