What Is Woven PP Fabric? Why It Is Used in Packaging

Reviewed and updated by ICD - Week 44/2026

Woven PP fabric is a cloth woven from flat tapes drawn from PP plastic (polypropylene), with warp and weft threads crossing at right angles, usually in a plain weave on a circular loom, and it can then be coated with a PP or PE film to make it waterproof. The fabric is light, strong in tension and hard to tear, so it is used for jumbo bags, farm produce sacks, geotextiles and the shell of woven PP dunnage bags. In ICD Vietnam documentation, the woven PP layer of a dunnage bag has a grammage of 70 gram.

I am Le Van Thang, and I have worked in packaging supplies at ICD Vietnam since 2011. Customers ask me about woven PP fabric usually for one very specific reason: whether to buy a dunnage air bag with a paper shell or a PP shell. To answer correctly you need to understand what the fabric is made of, where it is strong and where it is weak. This article goes in turn through construction, production, the specifications to read, the places woven PP is used and how to check it before buying.

What is woven PP fabric, and how does it differ from non-woven PP?

Woven PP fabric (woven polypropylene) is cloth that is really woven from threads, like clothing fabric in principle, except that the threads here are thin, flat strips of PP plastic rather than cotton fibre. Each lengthwise thread passes over and under the crosswise threads, forming a cloth with an even mesh visible to the naked eye.

It should be told apart from non-woven PP, the type still used for supermarket bags and face masks. Non-woven fabric is made by spraying molten plastic fibres into a layer and then heat-bonding them together, with no warp or weft threads. Both are made from PP, but their properties are very different: woven fabric resists tension and hanging loads far better, which is why it is used for sacks that hold heavy goods and for air bag shells.

How is woven PP fabric made?

The process has five main stages, the same in most woven PP packaging mills:

• Mix PP granules with additives (colour, UV stabiliser, antistatic agent if needed).
• Extrude the molten plastic through a flat die into a thin film, cool it and slit it into narrow tapes.
• Stretch the tapes in a heating chamber to orient the molecules, producing flat threads with high tensile strength.
• Weave the threads on a circular loom (giving tubular fabric with no side seam) or a flat loom, usually in a plain weave.
• Coat or laminate with PP or PE film if dust or moisture resistance is needed, then print, cut and sew into products.

The stretching stage is where the fabric’s strength is decided. When the plastic tape is drawn out while still hot, the PP molecular chains line up along the thread, so the thread is much stronger than the same amount of plastic left as film. That is why, for the same mass, woven PP fabric resists tension far better than ordinary PP film.

Why is woven PP fabric strong in tension and hard to tear?

Woven PP fabric is strong thanks to two factors added together: the threads themselves have been drawn and oriented, and the woven structure spreads force in two directions. When the cloth is pulled, the force travels along hundreds of parallel threads instead of concentrating on one point; when a sharp object pierces it, it has to push aside or cut the threads one by one, so a puncture does not spread as easily as in paper or thin film.

This is also why woven PP fabric is chosen as the air bag shell for cargo with sharp edges. Kraft paper, even multi-ply, is still pressed cellulose fibre, and against the edge of a wooden pallet, a steel strap or the rim of a metal unit rubbing constantly it is easily cut. Woven PP fabric withstands that kind of abrasion longer, so the inner bag is less likely to be pierced.

Heat resistance of PP is fairly good at ordinary transport temperatures, because commercial isotactic PP only melts at about 160 to 166 °C. At the other end, PP becomes brittle below 0 °C, so for cargo going to deep-freeze cold storage, the PP shell needs the manufacturer’s confirmation of its specification before use.

Specifications to read when choosing woven PP fabric

When reading a woven PP fabric data sheet, there are five figures worth noting. The table below explains what each one says; the specific numbers depend on the purpose of use, so compare within the same product group rather than comparing a farm sack with a jumbo bag.

Besides these five figures, for fabric used outdoors or stored for long periods ask about UV additives as well. The ISO 21898 standard for jumbo bags for non-dangerous goods has a whole annex on assessing a bag’s UV resistance, because ultraviolet light is the main reason woven PP fabric weakens over time.

Advantages and disadvantages of woven PP fabric

The biggest advantage of woven PP fabric is its strength-to-weight ratio. PP is the common plastic with the lowest density, about 0.895 to 0.93 g/cm³, and it is drawn into oriented threads, so the fabric is light yet carries large loads. A light sack uses less material, costs less to ship and is easier to handle.

PP is also chemically resistant: at ordinary temperature this plastic withstands oils and fats and almost all organic solvents, except strong oxidisers, and it can hold non-oxidising acids and bases. The plastic itself absorbs almost no water. However, uncoated fabric still has gaps between the threads, so it resists water only when coated or laminated.

The clearest disadvantage is that it is sensitive to UV light. The European jumbo bag association advises against leaving bags outdoors because UV and weather damage them; if they must be left outside they must be covered with black PE film or a suitable cover. The second disadvantage is that PP fabric does not biodegrade by itself, although it can be mechanically recycled into plastic granules for other products.

What is woven PP fabric used for?

Woven PP fabric appears in almost every stage of packing bulk and industrial goods. The four big groups of use are jumbo bags, farm produce and fertiliser sacks, geotextiles and tarpaulins, and the shell of dunnage bags.

Jumbo bags (FIBC) for bulk cargo

The jumbo bag, technically an FIBC (flexible intermediate bulk container), is the use that demands the highest quality woven PP fabric because the whole load is hoisted by the bag’s loops. According to guidance from the European jumbo bag association (EFIBCA), the bag label must state the safe working load (SWL) and the safety factor, usually 5:1, 6:1 or 8:1; only bags with a safety factor of 6:1 or higher may be reused, while single-use bags must never be reused.

A safety factor of 5:1 means the bag must withstand five times the safe working load in testing. This is the clearest example showing that with woven PP fabric you cannot go by appearance alone, but must read the label and the specifications.

Farm produce sacks, fertiliser sacks and technical fabric

Sacks for rice, sugar, coffee, animal feed, fertiliser and cement are mostly made of woven PP fabric, some coated with moisture-barrier film, some laminated with multicolour printed film. In construction and agriculture, wide woven PP fabric is used as geotextile for ground lining, site tarpaulins and ground cover netting. For this group, UV additives are almost a requirement.

Outer shell of woven PP dunnage bags

In a dunnage bag, woven PP fabric is the load-bearing shell wrapped around the air-holding inner bag. According to ICD Vietnam documentation, the inner bag is 75 micron PA film (with a PE layer) and the shell is 70 gram woven PP fabric; the paper-shell bag uses 65 gram plastic-laminated Kraft paper. To learn more about each layer, see the article on dunnage bag materials.

According to the ICD Vietnam catalogue, woven PP bags come in levels from Level 0 to Level 5, while the usual Kraft paper bag is Level 1. The strength level is decided by the construction of each bag code, not only by the shell material, so when ordering you need to state the level rather than only writing “PP bag”. The Level 1 to 5 scale comes from General Information Bulletin No. 9 of the Association of American Railroads (AAR), applied to cargo in rail cars in North America; cargo going by sea or road in Vietnam does not require an AAR-rated bag.

In my experience, woven PP bags suit heavy cargo with large inertia and rough surfaces best: steel coils, paper rolls, chemical drums, machinery. For cartons stacked flat on pallets, a Level 1 paper bag is usually enough and cheaper. For a business with a return flow between two warehouses, the PP bag has the added benefit of being reusable many times.

With reuse you have to account for degradation. The CTU Code of the IMO, ILO and UNECE sets the safety factor for reusable air bags at 0.5, lower than the 0.75 for single-use bags, precisely because the shell and valve may have weakened over previous uses. Before each reuse, check the shell under strong light, look closely around the valve and the seams, then inflate it as a test and leave it for a day.

Checking woven PP fabric and PP bags before buying

Whether you buy jumbo bags or woven PP air bags, the basic checks are the same. I usually follow this list when I receive a sample:

• Ask for the data sheet: fabric grammage, weave density, coating layer, tensile strength in both directions.
• Hold the fabric up to the light: the weave should be even, with no loose spots and no broken threads.
• Look at the cut edge and the seams: the edge should not fray, the stitches should be even, with no skipped stitches.
• For coated fabric: scratch the film lightly at a corner to see whether it lifts from the fabric.
• Ask clearly whether there are UV additives if the goods will be outdoors or stored for a long time.
• For air bags: check the level label, the working pressure printed on the bag and the seal of the valve.

Frequently asked questions about woven PP fabric

Is woven PP fabric completely waterproof?

No, if the fabric is uncoated. PP plastic absorbs almost no water, but there are still gaps between the woven threads, so water and fine powder can get through. For waterproofing, the fabric must be coated or laminated with PP or PE film, or a PE liner bag must be used inside the sack.

Is woven PP fabric toxic, and can it hold food?

PP plastic has recycling code number 5 and is widely used for food packaging. However, woven PP fabric may contain colour additives, fillers or recycled plastic, so for sacks holding rice, sugar or animal feed, ask the supplier for documents proving the material meets food-contact requirements for the exact batch.

How do PP-shell and Kraft-shell air bags differ?

They differ in the outer shell. According to ICD Vietnam documentation, the PP shell is 70 gram woven PP fabric, resists cutting well, is reusable and comes in Levels 0 to 5; the paper shell is 65 gram plastic-laminated Kraft paper, usually Level 1, cheaper and normally single-use. Cargo with sharp edges or heavy cargo should use PP bags.

Does woven PP fabric biodegrade?

No. PP does not biodegrade in a short time, but it can be mechanically recycled into plastic granules for other products. Woven PP sacks and bags that are reused many times also help reduce new waste.

What temperature can woven PP fabric withstand?

Commercial isotactic PP melts at about 160 to 166 °C, so the temperature inside a container in the sun does not damage the fabric. At low temperature, PP starts to become brittle below 0 °C; cargo for deep-freeze cold storage should ask the manufacturer for the fabric specification before use.

Can woven PP jumbo bags be reused?

Only bags with a safety factor of 6:1 or higher may be reused, according to the European jumbo bag association guidance; 5:1 bags are single-use. Before reuse you must check for both visible damage and invisible damage such as UV degradation.

Contact us for woven PP dunnage bag advice

References

• Properties of PP (polypropylene) plastic - British Plastics Federation (BPF).
• Wikipedia - Polypropylene: density, melting point, brittleness below 0 °C, chemical resistance (accessed 10/2026).
• EFIBCA - Questions and Answers: SWL label, safety factors 5:1, 6:1, 8:1, conditions for reuse, storage away from UV, recycling.
• IMO/ILO/UNECE CTU Code, MSC.1/Circ.1497 - safety factor for single-use and reusable air bags.
• ISO 21898:2024, Packaging - Flexible intermediate bulk containers (FIBCs) for non-dangerous goods: Annex A on assessing UV resistance.
• ICD Vietnam dunnage bag catalogue: 75 micron PA film, 70 gram woven PP fabric, 65 gram laminated Kraft paper, Levels 0 to 5, consulted October 2026.