Bottom gusseted bags are extremely useful in the world of polythene packaging, especially in food and industrial applications – but you can find lots of products on the market packaged in them. A gusseted bag is one that has extra material in certain areas, to add strength or maximise the bag’s volume, or both.
A gusset (for those of you chortling at the word!) is just an engineering term for “more material”, and gussets appear on bridges, bicycles, bras and, in our case – bags.
There are two main types of gusseted bags; side gusseted, and bottom gusseted. We’ve outlined the difference between these two in our last post, which we’ve linked to below:
Learn more – Side Gusset vs Bottom Gusset
To make things a little more complicated, bottom gusseted bags come in two main forms. One is the pouch-type, the other is the box-type – and the latter is actually a hybrid of side and bottom gusseted bags.
Let’s look at these two types of bottom gusseted bags more closely…
Learn more about bottom gusseted bags
The image above is of two white bottom gusseted bags – and these are the oval-bottomed, pouch-like version. This type of bottom gusseted bag is simple and strong, with fewer folds and seals, meaning fewer points of failure.
There are many ways to make a poly bag – but they all begin life as LFT (lay flat tubing). The simplest way of making a bag from LFT is to seal one end of it, and leave the other end open for filling and sealing at a later date.
With bottom gusseted bags, instead of being sealed into a simple bag shape, material at the bottom of the tubing is folded back up into the tubing and sealed along an edge, creating a base. The bag still folds flat, but can hold a greater amount when filled without stressing, notching, or causing the material to fail.
Pouch-type bottom gusseted bags can stand up unaided when filled, making them an excellent all-in-one packaging system for individual products. There’s no need for outer packaging, or even labels, because they can be printed directly.
Although they’re relatively cheap, super strong, printable and self-standing – oval bottom gusseted bags do have some downsides. The tapered shape means there’s less usable volume at the top, and also makes stacking filled bags more difficult.
So, let’s introduce the other kind of bottom gusseted bag: the box-type, bottom/side gusset hybrid:
The box shape is achieved by adding a series of folds along the cross-section of the LFT – just like in a side gusseted bag. The difference here is, instead of creating a simple seal, extra material is folded inward at the bottom, allowing the bag to open fully at the bottom as well as the sides.
This results in volume being maximised throughout the bag, as well as an incredibly stable base. The bags can also be stacked more reliably (depending on their final top seal), and because they’re squared off that the bottom instead of rounded, there’s far less wasted space in transport and storage.
Well, there may be a couple. Due to the more complex manufacturing, these boxy bags are more costly. Still, they are miles better at holding large quantities in a small footprint than other kinds of poly bag, gusseted or otherwise, while still offering all the benefits of polythene:
- Light, strong and versatile
- Moisture proof
- Impact absorbing
- Custom colours
- Recycled blends avoid PPT
And when you custom order bottom gusseted bags from NPF, you can specify exactly what polymer blend, gauge and strength is required – so you can package anything with an all-in-one solution!
Why should you use bottom gusseted bags?
If you’re packaging small, single-serving food items – like nuts or snacks – and need an all-in-one POS packaging solution, both types of bottom gusseted bag would be perfect for this (particularly the pouch kind). Similarly, electronics or accessories can be displayed in anti-static gusseted bags – or heavy and sharp items, like bolts and screws, can be packaged in a single, low cost piece of packaging, with less chance of notching.
But it’s not just small-scale packaging. Very large sacks can be produced from heavy duty polythene, with bottom gussets. These are incredibly strong, yet still light, and suited to carrying everything from construction aggregates to animal feed, in industrial quantities.
Even in a large format, bottom gusseted bags can stand when filled, offering more predictable, stable transport and storage – and while they might not be the perfect solution for all applications, they can certainly streamline packaging in many cases.
If you’d like to learn more, or start an order for custom designed polythene bags – just get in touch below.