Sealing & resealing bags

Buy from an extensive range of sealable and resealable bags, including grip seal bags, zip seal bags and self-seal bags.

Sealing and resealing bags are...

• Reusable polythene bags that can be opened and closed
• Designed for multiple use - open and close as many time as you like!
• Bags that can be sealed by a variety of means, including self-seal bags

Self-seal bags are...

• Manufactured with an integral sealing strip, located along the bag opening, to allow for easy opening and closure
• Also known as minigrip bags, mini-grip bags, gripper bags, grippa bags and resealable bags
• Ideal for securing bag contents and avoiding leakage or contamination
• Available in a variety styles to suit a range of uses, from storage bags to carrier bags
• Available in clear polythene with or without labels - to make a note of bag contents and help retrieval
• Available in variety of coloured opaque polythene - e.g. red, green, blue or black - to help with item storage and colour-coded retrieval
• Also available in more specialist polythene, from heavy duty grip seal bags to anti-static grip seal bags
• Sometimes referred to as zip seal bags. However…

Popular views on mail bags

Mail bags handled on tramways and other public service vehicles need tougher control than normal consignments because they are passed through mixed traffic, tight loading windows, and frequent stops. A secure bag is not enough on its possess if the handling system enables snagging, dragging, or wetting at the kerbside, so the material and closure have to suit the route as well as the contents. Strong outer construction, transparent identification, and sensible stacking all assist reduce delay and damage when bags are lifted in and out of vehicles. Treating them as a routine package rather than a time-sensitive mailing load soon leads to avoidable handling faults.

Plastic mailing bags become dead stock very quickly when mailing activity slows, and that leaves mixed sizes sitting in cupboards instead of moving through use. The problem is not only clutter; old bags take up picking space, interrupt stock rotation, and make it harder to come by the proper size when a dispatch job comes up. If bags have been folded repeatedly, crushed below other stock, or handled enough to lose their clean stop, reuse becomes less practical because seal quality and presentation beginning to suffer. Thin polythene suppliers still has a place for light parcels, nevertheless only when it is being turned above regularly. Once it beginnings sitting untouched, it changes from a useful consumable into wasted space.

Padded mail bags do above retain a package together; they assist match the pack to the product and reduce avoidable damage. A thin document mailer is fine for flat printed material, nevertheless once sharp corners, small components or coated items are involved, the additional cushioning makes a proper contrast. Bubble lining, moisture resistance and a robust seam all assist when bags are dropped, scraped or pushed through a busy sortation system. Even the adhesive closure requirements attention, because a weak seal can fail after a few handovers. Choosing the proper bag at the packing bench normally means less returns and less time spent on rework.

Plastic mail bags are a weak selection when a package can be squeezed, stacked, or dropped amid handling. The film may retain items together, nevertheless it gives very small protection against impact, so a boxed gift, a toy with fitted parts, or any product that relies on shape can arrive labeled or misshapen. On sorting belts and in cages, the load above often does more damage than the journey itself, because the bag only follows the outline of what is inside. A thin outer wrap works for flat or soft products, nevertheless once the contents need proper assist, the pack spec has already gone gross.

Large mail bags need to be chosen for the load they will transport, not for how roomy they appear when empty. Heavy contents like cash bundles or mixed mail put proper stress on the seams, corners and closure, and any disadvantage tends to display up once the bag is lifted, stacked or dragged across a dispatch floor. Woven sacks normally give superb strength below weight, while blown polythene suppliers brings more give, nevertheless neither works properly without the proper gauge, stitch density and forming control. A bag that sees sound at packing stage nevertheless fails in sorting or transport has been manufactured for the gross duty, and that means careful specification is cheaper than handling damage.

White mail bags do their optimal work when the load requirements to stay tidy, light and simple to handle. A well-manufactured co-extruded polythene suppliers bag gives enough strength for flat stock and small boxed products without turning awkward on a packing line, so it seals cleanly and stacks well on a pallet. The white stop also gives a brighter surface for labels and barcodes, which assists scanning and makes the consignment see tidy in transit. Just as useful, the plain outer face conceals the contents better than transparent film, so there is less temptation for casual interference. That balance of speed and restraint makes them a sensible selection for dispatch areas that want less snags.

Postal bags were judged first by how well they held together below rough handling, because a weak seam could turn a tidy consignment into loose mail on the depot floor. Cloth construction, stitching pattern, closure method and even the finished weight all affected how much strain the bag could take before the load started to work against it. A bag that kept its shape also stacked more reliably in vans and sorting sheds, which reduced crushed corners and awkward rework. Lighter bags helped with carrying and transport efficiency, nevertheless only if they still survived repeated cinching, dragging and overfilling. That balance between strength and tare weight decided whether the bag was a assist or a nuisance.

Bluelounge Postal Bag

A mailing bag has to suit above one size of product if it is going to work properly in proper dispatch use. A compact laptop may sit flat inside with the flap folding above neatly, giving a tidy shape that is easy to transport on a shoulder strap, while a larger unit may stand upright and turn the same bag into a slimmer tote with top handles. That flexibility matters in packing and fulfilment because a bag that adapts to alternative formats reduces the need for separate SKUs and awkward repacking. The better designs also leave room for accessories without bulging at the seams, which assists retain handling damage down.

Printed mailing bags need to be chosen for how they behave on the packing line, not only how they see on a shelf. A sharp design is wasted if the film gauge is also light for the contents, because corners, seams and stressed folds are where splits normally beginning. A heavier gauge may feel safer, nevertheless it can make the bag stiffer and harder to close cleanly, which slows packing and creates more waste. Seal quality has the same practical effect, particularly when bags are handled repeatedly, stacked in totes or brushed against cage sides. A bag that stays intact through those stages retains labour tidy and cuts down on returns caused by handling damage.

White jiffy bags stay popular in despatch work because they offer a light mailer that still gives proper protection and handles well on fast packing benches. Their value lies in the balance between weight and strength: a bag must resist knocks, survive rough transport and still close cleanly without the flap lifting or the seal picking up dust. White outer films also expose scuffs, adhesive labels and dirt more clearly than darker grades, so any disadvantage in handling shows up at once. That can be useful, because poor pack-line discipline becomes visible before it turns into complaints or returns.

Zip seal bags are…

• Manufactured with a metal zip fastener or zip seal, making them…
• A more premium bag than a grip seal bag
• Used for storing important documents, such as art portfolios or school project work
• Ideal for use as a wallet for conference delegates or for exhibition attendees
• Also known as zip bags, ziplite bags or zipper bags

Sealable, resealable and self-sealable - there's more than one way to seal a bag

Sealable bags

Any plastic bag that can be sealed shut can be described as a sealable bag.

The sealing process can be carried out by any means, including a bag tie or clip (e.g. a sandwich bag with a twist tie), an adhesive strip, either external (e.g. sealing any bag with cellotape) or internal (e.g. as with a mailing bag), an internal self-seal strip (e.g. as with a minigrip bag) or by heat sealing with an external sealer (e.g. as with vacuum bags).

So any plastic bag that is designed with a seal can be called a sealable bag. However, not all sealable bags can be called resealable bags.

Resealable bags

Only bags where the seal can be reused can be classified as resealable bags. Some bags, such as mailing bags, feature a single-use seal that can't be reused without tearing open the bag itself and thus rendering it useless. Mailing bags are a very convenient way of sending post - thanks to their integral adhesive seal - but, because their seal is strong enough to keep the mail contents secude until the bag is cut or ripped open by the recipient, then a mailing bag is not a resealable bag, although it is a sealable bag.

Self-seal bags

Not every sealable bag be called a self-seal bag. This monicker is reserved only for bags that can be sealed closed without using any external sealing accessory - including adhesive tape, clips or bag ties - and without the use of a heat sealer to melt the polythene and seal the bag.

The most popular types of resealable bags are grip seal bags. These bags, which are sometimes known as mini-grip bags, gripper bags or grippa bags, feature an integral seal that runs along the top of the bag.

The seal contains a male (single) and female (double) ridge of plastic on opposite sides of the bag opening. When the seal is squeezed gently between thumb and forefinger, the male ridge fits snuggly into the female ridges to close the bag. This seal protects the contents of the bag from moisture, dirt and other external contaminants.

It can be used over and over again, which means the grip seal bag is a sealable bag, a self-seal bag and a resealable bag.

This handy bag is available in a huge range of sizes, made from clear, coloured or black polythene, with or without labels to make handy notes on the bag and with specialist options including antistatic bags - to keep electrical components safe - and specimen bags with accompanying record cards - perfect for hospitals, doctors' surgeries and police stations.

Methods of sealing plastic bags

The most common ways of sealing a polythene bag are by:

Sealing the bag with ties or clips. Fasten any bag shut with a plastic clip or twist shut with a tie. A popular method of sealing food bags for domestic use (e.g. clip a packet of frozen peas shut before placing in freezer, twist a sandwich bag closed for a packed lunch etc.)

Sealing the bag with a built-in adhesive flap. Some bags such as mailing bags are manufactured with a flap opening, where the flap contains a built-in adhesive strip attached along its length. Simply remove the cover from the adhesive and press the flap down to seal.

Sealing the bag with a built-in grip or zip seal. A range of bags are available with an integral strip that seals shut either by squeezing the seal together (grip seal) or pulling closed (zip seal). Very handy for regular use as they can be used over and over, these bags also provide great protection from moisture, dirt etc.

Sealing the bag with a heat sealer. If you really want to seal your bag shut tight this is the method for you. A heat sealer will bond two pieces of plastic when placed together in the sealer and the sealer is closed shut. A one-time seal, this method of sealing bags is popular for vacuum packing food.

Where to buy sealing and resealing bags

Resealable bag manufacturers and suppliers include:

Ziplock Bags
The home of ziplock bags online, this website features everything you need on ziplock, zipper, ziplite, grip seal and all self-seal bags. With a huge range of products at great prices and free delivery within the UK, this is the number one ziplock website out there.
www.ziplockbags.co.uk

Self Seal Bags
Specialists in self-seal bags, this website stocks a huge range of resealable bags from grip seal to mini grip and ziplock to ziplite. Packed with loads of useful information to help you choose the right bag for you, with free delivery to UK addresses.
www.self-seal-bags.co.uk

Plastic Self Seal Bags
Discount Self Seal Bags is the place to go to get resealable plastic bags at discount prices. Also features loads of useful information on self-seal bags, including a handy buying guide to make sure you pick the right sort of resealable bag for you.
www.discountselfsealbags.co.uk

Minigrip Bags
A website loaded with information on minigrip bags - aka grippa bags - and all types of self-sealing bags, with list of the best places to buy them online. Features a useful guide to anti-static self-seal bags, what they are used for and how they work.
www.minigrip-bags.co.uk

Zip Seal Bags
Zip Seal Bags contains loads of great information on zip seal bags and other types of self-seal polythene bags and eco-friendly alternatives. It also features a handy list of online zip seal bag retailers.
www.zipsealbags.co.uk

Antistatic Bags
Antistatic bags is the number one website dedicated to antistatic bags. Containing a wealth of information on antistatic packaging and how it works, along with details of where to buy it at the best possible prices.
www.antistatic-bags.co.uk

Resealable Bags
Resealable-Bags is a division of Polybags Ltd, the UK's number one polythene manufacturer, that specialises in resealable bags. Offering an unrivalled range of resealable bags and other polythene packaging at the best prices online.
www.resealable-bags.co.uk

Advice from the web on mail bags

Plastic mailing bags create a recycling problem because plenty councils will not take them in kerbside assortments, so the bag often ends up in the gross waste stream. Their low weight makes them easy to issue, transport and dispatch, nevertheless it also means there is very small material value once they are used. Dark pigment can make sorting harder as well, since it reduces the appeal of the recovered plastic and can limit the options for reprocessing. The practical reply is to retain the format simple, use the lightest workable gauge and make the disposal route transparent at the point of use. That reduces pollution and improves the chance of the bag being handled properly.

Mail bags need a carting system that protects the load as much as it saves labour. In a mailroom, sacks and bags are often awkwardly shaped, easy to snag, and heavy enough to strain a handler if they are dragged or lifted by hand. A motorised utility cart takes the weight off the operator and retains bags moving in a controlled line, which matters when the route includes tight corners, lifts, ramps, or crowded back corridours. The practical earn is less twisting, less dropped mail, and less delays when sacks must be shifted quickly between cages, sortation points, and dispatch areas.

Plastic mailing bags work well for magazine mailing because they retain the cover visible while adding a light nevertheless useful barrier against dust, damp and scuffing. That visibility assists at packing benches, where staff can spot the proper issue or notice a fault without opening the pack, and it also makes receipt checks quicker further down the chain. The film is not there to keep safe against rough treatment on its possess, yet it does enough to retain print in decent condition through sorting, loading and last delivery. For periodicals that pass through several hands, that additional layer often means less complaints and less wasted stock.

Hot promotions in padded mail bags on aliexpress:

Padded mail bags reduce transit damage by giving small products a light outer shell and a softer layer inside, which assists when parcels are sliding down conveyours, being stacked in cages, or landing in courier sacks. The outside face requirements enough toughness to cope with abrasion, while the padding inside takes the sting out of scuffs, corner knocks and light compression. That balance suits fast-moving dispatch areas where mixed consignments are handled in a rush. Even so, the proper mail bag still relies on the item, because a poor seal, thin gauge or loose fit lets contents shift about and defeat the protection.

Plastic mail bags suit light, flexible products because they retain the outer pack close to the item size and avoid the bulk of a carton. That makes life easier on the packing line, where staff need to transport quickly through mixed consignments without wasting time building boxes or adding empty fill. The wider point is that the bag should match the product, not only the dispatch target: a clingy fit improves handling, cuts dead weight, and retains secondary packing lean. When the item is awkward enough to need structure, a bag is the gross reply, nevertheless for the proper products it speeds the all despatch process.

Large mail bags have to be chosen for the method they transport through the system, not only by the volume they can swallow. A robust bag that survives rough sortation can still cause trouble if it bulks up on a pallet, wastes storage cube, or sits awkwardly in a dispatch lane. The better specification balances film strength with seam quality and tare weight, because awkward contents often press hard on one panel and expose weak points. A controlled polythene suppliers grade with a proper gauge assists cut split failures while still allowing tidy stacking. That retains the load stable and prevents a simple packing item from becoming a handling headache.

White mail bags need to do above see clean on the dispatch bench. For slim items like documents, discs, and flat promotional packs, the bag has to stay flat, close properly, and survive the knocks that happen in sorting and delivery. A decent white surface assists with presentation, nevertheless the proper test is whether the seam grasps, the film or paper resists tearing, and the contents stay still instead of rubbing against the inside. When the bag is sized sensibly and sealed well, corners stay tidy and the load reaches its destination without scuffing.

Postal bags at 28 by 34 may see like a simple consumable, nevertheless the gauge selection determines how well they survive a mixed pack and the rough handling that follows. A film that is also light will stretch at the corners, split at the seams, or lose shape when heavier items settle into the load, while an above-heavy bag adds dead weight to all consignment and wastes capacity in storage and transport. Consistent polythene suppliers behaviour and a proper seal line matter because they retain the closure tidy and reduce failures amid bagging and sortation. That balance between strength and tare weight is what retains a mailing line moving without creating avoidable waste.

A bubble lined mailing bag in size E/2 gives lightweight products a better chance of arriving in saleable condition because the outer mailer and the air-filled lining work together to absorb knocks. For small items like accessories, printed matter or spare parts, that additional cushioning can reduce scuffing without the bulk of a carton, which assists when secondary packing requirements to stay lean. The oyster white face also presents a clean, neutral stop that suits most dispatch operations and makes labelling straightforward. When the contents are not fragile enough to justify a box nevertheless still need more protection than a plain bag, this sort of mailer often strikes the proper balance.

United Kingdom waterproof plastic custom printed mailing bags

Printed mailing bags need to be specified for the method they behave on the packing bench, not only for how they see once they reach the client. A co-extruded polythene suppliers bag with the proper gauge can stand up to sharp carton corners and awkward product shapes without turning into a handling problem for the warehouse team. If the film is also thin, splits and seal failures appear as soon as parcels are dropped, squeezed into cages, or pushed through dispatch. If it is also heavy, the additional stiffness slows folding and counting, and the finished consignment takes more space than the job requirements.

Research & Resources

For plenty more information on sealing and resealing bags, including the manufacturing process, types of self-seal bags available and their many uses, please visit:

PlasticBags.uk.com: Browse through a huge range of self seal bags websites or, if you are a manufacturer, list your products for free on this online directory specialising in self seal bags and other plastic packaging.

PackagingKnowledge: The UK packaging industry's number one website contains huge amounts of information and in-depth articles on self seal bags.

Goldstork: This free online directory features specially selected information and hand-picked features on a range of self seal bags and resealable bags.

What is static electricity?

Every object in the world - ourselves included - is made of atoms, which are in turn made of protons, neutrons and electrons. While neutrons have no charge, protons are positively charged and electrons are negatively charged.

In normal circumstances, the number of protons and electrons in an atom balance each other out, meaning that atoms have no charge. However, when two items rub together or separate, the electrons contained within these items can move from atom to atom or even from item to item, thus giving the atoms a positive or negative charge.

If the items involved in this situation are made from a material that does not conduct electricity - an insulator - then this charge can not move. The result is static electricity.

How do antistatic self-seal bags work?

If any static electricity comes into contact with an antistatic self-seal bag, rather than pass through the bag and risk damaging the electrical components inside the bag, the electricity passes around the bag and dissipates before it can make contact with the components, thus removing the possibility of damage.