OPP Bag Closures and Headers: Strips, Hang Holes and Print

How an OPP bag closes and how it is displayed shapes the moment your product meets the customer. A piece of jewellery on a store peg and a T-shirt sent by courier need very different bags. This guide covers the strip options, header and hang hole types, air holes and when it pays to print, from the point of view of the people who make the bags.

Closing the bag: self-seal, courier tape or no strip

There are three basic ways to close an OPP bag. The right one depends on how often the bag will be opened and how secure the contents need to be.

• Self-seal adhesive strip: an adhesive strip on the flap, protected by a release liner, lets the bag be opened and closed again. It is the natural choice for retail garments that shoppers unfold and put back.
• Courier tape: courier (cargo) tape is permanent. Once sealed, trying to open it tears the film or leaves a clear mark, so anyone can see whether a parcel has been tampered with. It suits e-commerce shipments, documents and invoice pockets.
• No strip: an open-mouth bag closed by heat sealing, a label or separate tape. If you pack in-house with a sealer, this is the most economical option.

The strip runs the full width of the bag, so on wide bags it makes up a larger share of the cost. Courier tape uses a stronger adhesive and costs a little more per metre than a standard strip.

Headers and hang holes

Products sold on pegs or display stands get a header at the top of the bag: a double layer of film joined by ultrasonic welding. Instead of melting the film with heat, ultrasonic welding fuses it with high-frequency vibration, giving a flat, strong and tidy header. Because the header is double film, it is added twice in the film calculation, so a header bag weighs slightly more than a plain bag of the same size.

The hole itself is chosen to fit the hook and the look you want:

• Sombrero (Mexican hat): a sombrero hang hole combines a round centre with two side wings. It works on single pegs and twin-prong hooks and spreads the load well for heavier items.
• Euro slot: the euro slot is a horizontal slot with a rounded centre, the shape you see on most retail stands.
• Oval: a simple horizontal oval that slips onto hooks easily and keeps a clean look.
• Round hole: the round hang hole is the simplest and cheapest, perfectly adequate for light goods on wire hooks.

Header bags can be made with or without an adhesive strip. Common sizes are listed on the header OPP bag page.

Do you need air holes?

OPP film does not breathe. When soft, bulky items such as knitwear are bagged and sealed, the trapped air balloons the pack, bags slide around in the carton and the seals take extra strain. Air holes are small perforations that let that air escape. We recommend them for jumpers, cushions, towels and any fast packing line. Leave them out when the product must stay fully closed against dust.

When printing is worth it

Clear OPP bags work well unprinted: the product sells itself. Printing earns its place when it adds brand recognition, product information or shelf impact. We print with flexo in up to 8 colours. Points to plan around:

• Plates: each colour needs its own printing plate. The plate cost is charged once per colour for each design and is not charged again on repeat orders of the same artwork. Our calculator shows it separately rather than folding it into the unit price.
• Colour count: every extra colour adds a plate and adds to the print cost. A one-colour logo is often the most efficient result.
• Lead time: printed jobs take longer than plain ones because the plates have to be made first.
• Keep a window: leaving the area in front of the product unprinted preserves the clarity that is OPP's main strength.

On long-running, repeat orders the plate cost is spread thin very quickly. For a single small run, a plain bag with a sticker may make more sense.

Common mistakes to avoid

• Counting the flap in the length: length is given without the flap. Include it and the bag comes out short, with the strip sitting on top of the product.
• Forgetting the header on hanging bags: the header sits above the product area, so size the bag for the product first and let the header be added on top.
• Using a reclosable strip for parcels: if the pack goes straight to the end customer, a permanent courier tape shows whether it was opened in transit.
• Too many colours on a small run: each colour is another plate, so one colour or a plain bag with a label is often the better deal on short orders.

Side-by-side comparison

Making the final call

Start with where the product is sold: on a shelf, on a peg or straight into a shipping box. Then think about how many times the bag will be opened. A garment that shoppers try and return to the rack points to the self-seal OPP bag; an item going directly to the end customer points to the courier-tape OPP bag; anything displayed on a stand starts with a header bag.

To see every option together, open the OPP bag calculator and switch strip type, header, air holes and colour count to watch the effect on price instantly. The current minimum for bags is 20,000 pieces, and the calculator always shows the latest figure. If you are torn between two options, get in touch and we will help you pick the closure and header that suit your product.