Custom Non Woven Bag or Woven PP? The Fabric and Seam Spec Most Quotes Leave Out

Two quotations land in your inbox. Both say “non-woven bag, 90gsm, printed one colour, 300 pieces minimum”. One is noticeably cheaper. Nothing in either document explains why — because the two most important variables, what the fabric actually is and how the bag is joined together, are almost never written down. We have quoted against enough Malaysian tenders to know that this gap is where most disappointing deliveries begin.

This guide is about the two things a spec sheet usually omits. First, the difference between spunbond non-woven polypropylene and woven polypropylene — two genuinely different fabrics that both get sold under the word “PP bag”. Second, the seam: ultrasonic welding versus stitching, which is the single biggest predictor of whether a bag survives its second month. If you are about to sign off a custom non-woven bag order, these are the four lines to add to your request for quotation.

Two fabrics, one name

Spunbond non-woven polypropylene — what most people mean

Molten polypropylene is extruded through fine holes into continuous filaments, blown onto a moving belt to form a random web, then bonded by heat and pressure between engraved rollers. No spinning of yarn, no loom, no interlacing. The fabric is literally fused together at thousands of small points — and those bond points are the faint, regular diamond or dot pattern you can see if you hold a non-woven bag up to a window.

The result is light, soft, opaque, cheap at volume, and easy to cut and join. It is what supermarket giveaway bags, conference totes and gift-with-purchase carriers are made from.

Woven polypropylene — a completely different animal

Here, polypropylene is extruded as a film, slit into narrow flat tapes, stretched to orient the polymer, and then woven on a loom exactly like a textile. You get a visible crosshatch of flat plastic tapes. This is the fabric of rice sacks, fertiliser bags, bulk FIBC sacks and the glossy laminated shopper bags you see at hypermarket checkouts. It is far stronger under load, stiffer, noisier, and it is usually laminated with a printed film because raw woven tape prints badly.

Where each one actually wins

Property	Non-woven PP (spunbond)	Woven PP (tape)
Feel	Soft, cloth-like, matte	Stiff, slightly plasticky, often glossy once laminated
Load capacity	Light to moderate; depends heavily on construction	High — this is sack fabric
Tear resistance	Modest; a snag can start a run	High; tapes arrest a tear
Printing	Silkscreen directly; full colour via heat transfer or lamination	Almost always a pre-printed laminated film
Folds flat	Excellent — critical for shipping and in-store distribution	Poor; bulky in the carton
Cost at volume	The lowest of any reusable bag fabric	Higher per piece
Typical use here	Event totes, gift-with-purchase, delegate bags, campaign giveaways	Hypermarket checkout bags, rice and feed sacks, heavy-duty carriers

For almost every corporate gifting and campaign brief in Malaysia, spunbond non-woven is the right answer — which is why the entire non woven bag Malaysia specification list is built around it. Woven PP only becomes the right call when the bag is genuinely a load-carrying tool rather than a branded giveaway.

The seam question: ultrasonic welding versus stitching

Because polypropylene is a thermoplastic, two pieces of it can be joined without any thread at all. An ultrasonic horn vibrates at high frequency against the fabric; the friction generates heat at the interface, the polymer softens and the two layers fuse. It takes a fraction of a second, uses no consumables, and it is why an ultrasonically welded non-woven bag can be produced so cheaply.

Stitching does what stitching has always done: a thread passes through both layers and distributes the load along a line, and the join can be reinforced with a box stitch or a bar tack at the points that take the most stress.

Seam	How it is made	Typical failure mode	Where it belongs
Ultrasonic welded	Fabric fused by high-frequency vibration; no thread	The weld peels apart under a sudden or angled load, usually starting at one end of the weld line	D-cut handle bags, single-occasion giveaways, drawstring pouches, very high volumes
Fully stitched	Sewn with thread through both layers	Thread abrasion over many months, or the needle line perforating if stitch density is too high	Delegate bags, gift-with-purchase carriers, anything reused
Welded body, stitched handles	Fast welded panels with sewn and reinforced handle joins	Base seam before handles — the opposite of the usual order	The value option when budget is tight but handles must hold
Stitched with bar-tack reinforcement	Stitched, plus a dense cross-stitch block at each handle anchor	Rarely fails at the handle; the fabric goes first	Grocery bags, hamper carriers, anything carrying bottles

The practical rule we give buyers: a welded seam is strong in shear and weak in peel. Bags fail in peel. A bag that sits on a table full of documents will be fine welded. A bag swung off a shoulder with a 1.5-litre bottle inside is applying exactly the force a weld is worst at resisting.

What actually goes wrong — three things from the production floor

1. The weld that opens like a zip

Welded seams do not usually tear in the middle. They start at one end and unzip. That is why a welded bag can look perfect in the sample and fail suddenly in use: the sample was never loaded at the angle that starts the peel. When we assess a welded sample we always pull at the ends of the weld line, never the middle.

2. Stitch density that perforates instead of joins

Non-woven has no yarn structure to close around a needle hole. Set the stitch too fine and you have effectively punched a tear-off line into the fabric, and the seam fails alongside the thread rather than through it. This is a real and avoidable production error; it is one of the specific things we look for on a pre-production sample.

3. Handle anchoring depth

Handle strength is mostly a function of how far down the body the handle is attached, not the handle material. A handle stitched over 60mm of body distributes load across roughly three times the area of one stitched over 20mm. Ask for the anchoring depth; almost nobody does. It is a close relative of the fabric-weight question we work through in the guide to the GSM band you write into the spec.

Laminated non-woven: a third fabric hiding inside the same word

There is a third product that also gets called “non-woven bag”: spunbond fabric with a thin biaxially oriented polypropylene film laminated onto its face. It looks and behaves quite differently.

• Printing changes completely. The artwork is printed on the film, not on the fabric, so full-colour photographic and edge-to-edge designs become straightforward. This is what most suppliers mean by “full colour non-woven”.
• It is wipe-clean and water-resistant on the laminated face, which is why it turns up on hamper carriers and food-related campaigns.
• It is stiffer and folds less flat, so cartons take more volume for the same piece count.
• It stops being a single-material product. Plain non-woven is polypropylene and nothing else. Laminated non-woven is a film bonded to a web, and mixed-material laminates are a recognised difficulty for recycling. If a recyclability claim is going on the bag, that distinction matters — we go through what is defensible in the piece on high-volume non-woven giveaway runs at events.

The four lines to add to your request for quotation

Four lines. They cost you nothing, they make two quotations genuinely comparable, and they give you something concrete to check the delivery against. For government and statutory-body buyers writing an ePerolehan specification, these are also the lines that make an audit trail possible — a tender that says only “non-woven bag 90gsm” cannot be enforced.

Which construction for which Malaysian brief

Brief	Fabric	Seam we would specify
Single-day roadshow or exhibition handout	Spunbond, 75–80gsm	Ultrasonic welded — the bag has one job and volume is the point
Conference delegate bag	Spunbond, 90gsm	Fully stitched; the bag is carried loaded all day
Supermarket reusable shopping bag	Spunbond, 100gsm+, boxed base	Stitched with bar-tacked handles
Festive hamper carrier	Laminated non-woven	Stitched, with a base board
Heavy goods, agricultural or industrial carry	Woven PP	Stitched, hemmed top
Pharmacy or retail carrier bag	Spunbond, 80–90gsm	Welded body, stitched handles

Whichever route you take, the fabric and seam decision comes before the artwork decision, because the construction determines which decoration methods are even available — something we unpack in the guide to printing ink onto polypropylene fabric.

Frequently asked questions

Is a non-woven bag the same as a PP bag?

Not necessarily. “PP bag” only tells you the polymer is polypropylene. It could be spunbond non-woven or woven tape fabric, and those are different products with different strengths and prices. Always ask which one you are being quoted.

Are stitched non-woven bags worth the extra cost?

If the bag will be reused, yes — the handle join is where bags fail, and stitching plus reinforcement is what fixes it. If the bag is handed out at a one-day event and will realistically be used a handful of times, a welded bag does the job and lets you buy more of them.

Can you weld and stitch the same bag?

Yes, and it is often the best value. Welding the body panels keeps the unit cost down while the handles, which take the real load, are sewn and reinforced.

Which is stronger, woven or non-woven polypropylene?

Woven PP carries far more weight and resists tearing better. Non-woven is softer, prints more easily, folds flat and costs less at volume — which is why it dominates promotional and event use even though it is the weaker fabric.

What is the minimum order and lead time?

From 300 pieces per design. Production takes 21–45 days after artwork approval depending on quantity and construction, plus around 15 days shipping. Express production in 10 working days is available on limited styles and quantities.

Can you supply documentation for tenders?

Yes. We can put fabric weight, seam construction, handle specification and finished dimensions in writing so they can be quoted in an ePerolehan submission and checked against on delivery, with an SST invoice.