Minimum Order Quantity (MOQ): 1 pallet (typically 125–250+ bulk bags)
An uncoated fabric bulk bag is an FIBC made from woven polypropylene fabric without an additional polypropylene coating applied over the weave. That leaves the natural woven structure more breathable, allowing more air to move through the fabric than a comparable coated FIBC. Uncoated bulk bags can be an excellent choice for coarse powders, granules, pellets, agricultural products, minerals, recycling materials, and other suitable dry bulk products where maximum fabric barrier performance is unnecessary or breathability is beneficial. But “uncoated” only describes the fabric treatment. It does not tell you the bag’s strength, SWL, safety factor, body construction, top, bottom, liner, loops, dimensions, discharge performance, or suitability for your product.
Uncoated fabric sounds like the simpler option.
Sometimes it is.
But do not confuse simpler with inferior.
There are applications where uncoated woven polypropylene is exactly what you want.
There are also applications where using it can create:
Sifting.
Dust.
Product loss.
Moisture problems.
Contamination issues.
The trick is knowing which application you have.
An uncoated FIBC uses woven polypropylene fabric without the additional coating commonly used to close more of the natural openings in the weave.
Polypropylene tapes are woven together to create the fabric.
Because those tapes are woven rather than formed into one completely solid sheet, small openings naturally exist within the structure.
Those openings allow greater air movement through the fabric.
It means the woven polypropylene fabric does not have the additional coating used on coated FIBC fabric.
It does not mean:
Weak.
Cheap.
Low quality.
Single use.
Low SWL.
Non-food-grade.
A specific FIBC type.
A specific body construction.
A specific top or bottom.
Those are separate specifications.
Because not every product requires additional fabric barrier performance.
For some applications, the natural woven fabric provides exactly the performance needed.
And in some filling processes, greater breathability is actually useful.
Breathability.
Air can move more readily through uncoated woven fabric.
That can be particularly useful during filling.
Product enters the FIBC.
The air already inside needs somewhere to go.
Uncoated fabric can provide additional paths for that displaced air.
The same open weave that allows greater airflow can also allow:
Very fine particles to migrate.
More moisture movement through the fabric.
That is the tradeoff.
More breathability.
Less fabric barrier.
| Feature | 💨 Uncoated Fabric | 💧 Coated Fabric |
|---|---|---|
| Breathability | Higher | Lower |
| Natural air displacement | Better | Reduced |
| Fine-particle containment through weave | Lower | Better potential |
| Moisture resistance through fabric | Lower | Improved |
| Filling airflow | Often advantageous | Requires more attention |
| Liner compatibility | ✅ | ✅ |
| Multiple body styles | ✅ | ✅ |
| Multiple tops/bottoms | ✅ | ✅ |
| Automatically suitable for all products | No | No |
| Automatically waterproof | No | No |
Neither construction wins every application.
Potential applications include suitable:
Granules.
Pellets.
Coarse powders.
Agricultural materials.
Recycling materials.
Minerals.
Aggregates.
Industrial raw materials.
Plastic materials.
Other dry bulk solids.
The actual particle characteristics matter more than the product category.
Granular materials can be strong candidates when the particles are large enough that migration through the weave is not a meaningful concern.
But “granular” is still broad.
Know the actual product.
Many pelletized materials may not require the additional fabric barrier provided by coating.
The product should still be evaluated for:
Particle size.
Dust generation.
Moisture sensitivity.
Abrasion.
Static requirements where applicable.
Some agricultural products may benefit from greater fabric breathability.
But do not assume every agricultural material belongs in an uncoated FIBC.
Moisture sensitivity and product cleanliness can change the decision.
Coarser mineral products may work well in uncoated fabric.
Fine mineral powders may require additional containment.
Particle size and dust behavior are critical.
Suitable recycling applications may benefit from the simplicity and breathability of uncoated woven fabric.
Again, evaluate:
Particle size.
Sharpness.
Abrasion.
Payload.
Handling.
Discharge.
Sometimes.
“Powder” does not tell you enough.
A relatively coarse powder may behave very differently from an extremely fine powder.
The question is:
Can the product migrate through the weave or create unacceptable dust?
Test the actual material.
Because the woven structure contains natural openings.
If particles are sufficiently fine, they may migrate through those openings.
This can create:
Product loss.
Dust.
Dirty pallets.
Dirty equipment.
Housekeeping problems.
Customer complaints.
Even if most of the product is too large to sift, the product may contain a fine fraction that creates dust.
Do not evaluate only the average particle size.
Look at what actually happens during:
Filling.
Handling.
Storage.
Transportation.
Discharge.
Imagine filling an FIBC rapidly.
Product enters.
Air gets displaced.
That air needs to escape.
More breathable fabric can make that process easier.
Uncoated fabric can be advantageous in filling systems where significant air displacement occurs.
Potential benefits include:
Less bag inflation.
Faster air release.
Reduced product backup.
Better filling efficiency.
But do not assume fabric breathability alone solves every filling issue.
Some products carry substantial air into the FIBC during filling.
In these applications, air management becomes important.
Uncoated fabric may provide useful natural airflow.
Test the real product at the real filling rate.
Packaging should be evaluated by more than unit cost.
Measure:
Bag setup.
Connection.
Filling.
Air displacement.
Closure.
Total cycle.
A few seconds per FIBC can become substantial at high annual volume.
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No.
The actual airflow characteristics depend on the complete fabric and FIBC construction.
And adding a liner can dramatically change the behavior of the package.
Absolutely.
This is important.
Uncoated does not mean unlined.
You can have an uncoated woven polypropylene outer FIBC with an internal liner.
The outer woven FIBC and internal liner perform different jobs.
The woven fabric provides structural support.
The liner may provide additional:
Moisture protection.
Fine-particle containment.
Product-contact protection.
Contamination control.
Other barrier performance.
It can significantly change overall airflow.
That is why you should not assume:
Uncoated outer fabric = highly breathable complete package.
If the liner prevents displaced air from escaping, the outer fabric’s breathability may not solve the filling problem.
Loose liners can be practical.
But they can:
Shift.
Wrinkle.
Fold.
Move during filling.
Interfere with discharge.
Test them in the actual process.
Form-fit liners can provide more controlled internal geometry.
Potential advantages include:
Reduced excess film.
Better positioning.
More predictable filling.
More predictable discharge.
But use them because the application needs them.
| Requirement | 💨 Uncoated Fabric | 🛍️ Liner |
|---|---|---|
| Structural woven body | ✅ | No |
| High fabric breathability | Better potential | Can reduce overall airflow |
| Fine-particle barrier | Lower | Potentially much higher |
| Moisture barrier | Lower | Application dependent |
| Separate component | No | Yes |
| Can shift internally | No | Possible |
| Can affect discharge | Fabric generally less direct | Yes |
| Automatically waterproof | No | No |
Yes.
Circular describes the tubular woven body construction.
Uncoated describes the fabric treatment.
A circular FIBC can use coated or uncoated fabric.
Yes.
U-panel body construction can use uncoated woven polypropylene when appropriate.
Yes.
The body uses four separate side panels, but those panels can be made from appropriate uncoated fabric.
Yes.
Baffles address filled shape.
Uncoated describes the outer fabric treatment.
Different design variables.
| Construction | Main Function | Can Be Uncoated? |
|---|---|---|
| 🔵 Circular | Tubular woven main body | ✅ |
| 🧵 U-Panel | Continuous main panel + side panels | ✅ |
| 📦 Four-Panel | Four separate side panels | ✅ |
| 🧱 Baffle | Internal shape control | ✅ |
Do not confuse fabric treatment with structural architecture.
Open tops provide broad filling access.
They can be useful when:
Fast loading matters.
Product exposure is acceptable.
A separate closure is unnecessary.
But product containment after filling must be considered.
Duffle tops can provide:
Broad filling access.
Closure after filling.
They can be useful across many suitable dry bulk applications.
Filling spouts can provide controlled equipment interfaces.
Uncoated fabric may assist with air displacement through the fabric, depending on the complete package.
Still evaluate the actual filling rate.
Flat bottom can work when controlled bottom discharge is unnecessary.
The fabric treatment does not determine the bottom style.
Discharge spouts can provide controlled unloading for suitable free-flowing products.
Match the outlet to:
Particle size.
Flowability.
Receiving equipment.
Desired discharge rate.
Duffle bottoms provide broad discharge access.
They can be useful for suitable:
Bulky products.
Irregular products.
Materials prone to bridging.
Rapid-discharge applications.
Potentially—but this is where you need to be careful.
Very fine powder can migrate through the woven fabric.
If the application requires significant fine-particle containment, you may need to consider:
Coated fabric.
Appropriate seam construction.
A liner.
Different closures.
A combination of these.
No.
Neither are coated FIBCs automatically dustproof.
Dust containment depends on the complete system.
No.
Uncoated woven polypropylene should not be treated as a waterproof barrier.
If moisture protection is critical, define the actual requirement.
The polypropylene material itself has useful properties, but an uncoated woven FIBC contains openings in the weave and other possible entry paths.
Do not convert that into a blanket claim that the complete FIBC is water resistant enough for your application.
Test the actual packaging system.
Use caution.
If the product is highly sensitive to moisture, uncoated fabric alone may not provide the required protection.
Consider:
Coated fabric.
Liner.
Top closure.
Bottom closure.
Seams.
Storage conditions.
Transportation environment.
Do not assume a polypropylene FIBC can simply sit outside indefinitely.
Outdoor exposure introduces:
Rain.
Humidity.
UV.
Temperature changes.
Condensation.
Standing water.
Handling damage.
Storage duration.
Define the real environment.
If the FIBC will spend meaningful time outdoors, communicate expected UV exposure.
Do not treat fabric coating as the only variable affecting outdoor performance.
Moisture problems can come from temperature changes as well as direct water exposure.
Think about:
Product temperature.
Ambient temperature.
Humidity.
Storage.
Transportation.
A buyer might assume:
“If the fabric is already open-weave, seams don’t matter.”
Wrong.
Seams remain critical to:
Structural performance.
Containment.
Shape.
Top construction.
Bottom construction.
Fine-particle control.
You can have an uncoated FIBC with additional seam considerations for a particular application.
Fabric treatment and seam construction are separate decisions.
Uncoated does not mean lower SWL.
Specify the required Safe Working Load independently.
Safety factor is also separate.
Do not infer safety factor from:
Fabric appearance.
Coating.
Bag weight.
Color.
General descriptions like “heavy duty.”
Fabric construction needs to support the complete application.
Consider:
Payload.
Handling.
Product.
Abrasion.
Body construction.
Top.
Bottom.
Loops.
Overall design.
Bulk density is one of the most important pieces of information when selecting an FIBC.
It affects:
Required volume.
Payload.
Filled dimensions.
Warehouse cube.
Transportation.
Determine whether the product:
Flows freely.
Bridges.
Cakes.
Clumps.
Compacts.
Interlocks.
That influences filling and discharge.
Abrasive material can wear:
Fabric.
Seams.
Bottom areas.
Discharge components.
Communicate the actual product characteristics.
Sharp products can create:
Puncture concerns.
Localized wear.
Fabric damage.
Liner damage.
Evaluate the real material.
If product enters the FIBC unusually hot or cold, define those operating conditions.
Not automatically.
Food-grade suitability depends on the complete approved materials, manufacturing conditions, handling requirements, and applicable product-contact specifications.
Not automatically.
UN certification applies to a complete tested packaging design.
Uncoated fabric alone tells you nothing about UN certification.
Uncoated fabric alone does not tell you the electrostatic classification of the complete FIBC.
If static hazards are relevant, specify the required FIBC type separately.
Coating does not determine whether an FIBC is approved for repeated use.
Reuse depends on the complete design, intended-use classification, safety factor, inspection procedures, condition, and applicable requirements.
Potential advantages include:
Greater fabric breathability.
Better natural air displacement.
Potentially easier high-speed filling.
Simple woven fabric construction.
Potentially lower unnecessary material cost when coating provides no value.
Compatibility with liners.
Compatibility with multiple body constructions.
Compatibility with multiple tops.
Compatibility with multiple bottoms.
Good performance across many suitable coarse and granular products.
Potential disadvantages include:
Greater potential for fine-particle migration through the weave.
Lower moisture resistance through the fabric.
Potential product loss with very fine materials.
Potential dust and housekeeping issues.
May require a liner for demanding barrier applications.
May not be appropriate for moisture-sensitive products without additional protection.
Neither.
If you need:
Fine-particle containment through the fabric.
Improved moisture resistance through the fabric.
Then coated may make sense.
If you need:
Greater breathability.
Better natural air displacement.
And fine-particle migration is not a problem.
Then uncoated may make more sense.
The product decides.
The process decides.
Consider uncoated fabric when:
The product does not significantly migrate through the weave.
Fabric moisture resistance is not critical.
Breathability is beneficial.
The filling process generates substantial displaced air.
A separate liner handles the required barrier function.
Coating would add cost without solving a meaningful problem.
Be cautious when:
The product is extremely fine.
Sifting is unacceptable.
Dust containment is critical.
The product is highly moisture sensitive.
The outer fabric itself needs stronger barrier performance.
The application has demanding cleanliness requirements.
Do not choose fabric in isolation.
Ask:
How does product enter?
How quickly?
How much air travels with it?
Where does displaced air go?
Does the FIBC inflate?
Does product back up?
Does dust escape?
The answers may make fabric breathability extremely important.
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Fabric treatment is only one part of the system.
Also ask:
How does product leave?
What outlet is used?
How fast should it discharge?
Can downstream equipment handle the flow?
Does product bridge?
Does a liner interfere?
Specify loops around actual handling equipment.
Consider:
Loop style.
Loop length.
Forklift access.
Filling equipment.
Discharge equipment.
Operator handling.
Calculate the entire suspended package:
Body.
Loops.
Top.
Bottom.
Then verify equipment clearance.
Never approve pallet fit from an empty FIBC.
Fill the bag.
Use the intended payload.
Place it on the actual pallet.
Measure:
Width.
Length.
Height.
Overhang.
Product can settle after filling.
That can change:
Height.
Width.
Length.
Footprint.
Stability.
Transportation characteristics.
Measure after representative settling.
Evaluate:
Loaded footprint.
Loaded height.
Overhang.
Handling clearance.
Storage conditions.
Humidity.
Product protection.
Warehouse cube.
Consider:
Vibration.
Settling.
Humidity.
Temperature changes.
Handling.
Pallet movement.
Transit duration.
Product containment.
The FIBC must work through the entire logistics chain.
Common mistakes include:
Assuming uncoated means cheap.
Assuming uncoated means weak.
Assuming uncoated is always more economical.
Assuming every product benefits from breathability.
Ignoring particle size.
Ignoring the fine fraction of the product.
Ignoring dust.
Ignoring product migration through the weave.
Ignoring moisture sensitivity.
Assuming polypropylene means waterproof.
Ignoring seams.
Ignoring needle holes.
Ignoring top closure.
Ignoring bottom closure.
Ignoring filling equipment.
Ignoring filling rate.
Ignoring air displacement.
Ignoring liners.
Assuming an uncoated outer FIBC with a liner remains highly breathable.
Ignoring liner movement.
Ignoring bulk density.
Ignoring target payload.
Ignoring SWL.
Ignoring safety factor.
Ignoring body construction.
Ignoring product flowability.
Ignoring abrasion.
Ignoring sharp particles.
Ignoring temperature.
Ignoring static requirements.
Assuming uncoated means food grade.
Assuming uncoated means UN certified.
Ignoring pallet fit.
Ignoring warehouse conditions.
Ignoring nationwide transportation.
Comparing only unit price.
Do not write only:
Uncoated bulk bag.
A better starting point is:
Fabric: Uncoated Woven Polypropylene Per Approved FIBC Specification and Drawing
Then define:
Product.
Particle characteristics.
Bulk density.
Target payload.
SWL.
Safety factor.
Body construction.
Fabric.
Seams.
Top.
Bottom.
Liner.
Loops.
Dimensions.
Tolerances.
Filling.
Air displacement.
Discharge.
Pallet.
Printing.
Packing.
Revision.
Before ordering, confirm:
📦 Product: What exactly is going inside?
🔬 Particle Size: Can it migrate through the weave?
🌫️ Dust: Does the product create a fine fraction?
⚗️ Bulk Density: What is the actual density?
⚖️ Payload: What is the intended fill weight?
💨 Breathability: Is greater airflow beneficial?
🌬️ Air Displacement: How does air escape during filling?
💧 Moisture: Is lower fabric barrier performance acceptable?
🪡 Seams: Are structural and containment requirements defined?
🛍️ Liner: Is one required?
🔝 Top: Does it match the filling process?
⬇️ Bottom: Does it match discharge?
🧶 Body: What construction is required?
⚖️ SWL: Is it correctly specified?
🛡️ Safety Factor: Is it correct for the intended use?
⚡ Static: Are electrostatic requirements applicable?
🪢 Loops: Do they match the equipment?
📐 Filled Geometry: Has the loaded FIBC been measured?
🪵 Pallet: Has the actual pallet been tested?
🏭 Warehouse: Does the package work in storage?
🚚 Transportation: Does it work through nationwide logistics?
📄 Revision: Is the approved specification controlled?
🧪 Testing: Has the actual product been tested?
Ask:
Start with the product.
Not the bag.
Determine:
Particle size.
Fine-particle content.
Particle shape.
Bulk density.
Flowability.
Dust behavior.
Moisture sensitivity.
Abrasion.
Sharpness.
Temperature.
Static considerations when applicable.
Target payload.
Now ask:
Do we actually need a fabric barrier?
If the answer is no, uncoated fabric may be exactly what you want.
Then ask:
Would greater fabric breathability help the filling process?
Now you are getting somewhere.
Define:
SWL.
Safety factor.
Body construction.
Top.
Bottom.
Seams.
Liner if required.
Loops.
Dimensions.
Pallet.
Then run an actual filling test.
Use the real product.
Use the intended payload.
Use the real filling equipment.
Run at production speed.
Watch:
Air displacement.
Bag inflation.
Product backup.
Dust.
Product migration through the fabric.
Seams.
Liner behavior.
Measure filling cycle time.
Then put the loaded FIBC on the actual pallet.
Measure:
Width.
Length.
Height.
Overhang.
Allow representative settling.
Measure again.
Store the package under representative conditions.
Evaluate:
Humidity.
Temperature.
Product containment.
Moisture exposure.
Handling.
Move it through representative nationwide transportation conditions.
Then discharge it through the actual receiving equipment.
Measure:
Discharge time.
Flow.
Bridging.
Surging.
Dust.
Spillage.
Liner behavior.
Residual product.
Operator intervention.
Finally, calculate the economics.
FIBC cost.
Filling labor.
Cycle time.
Product loss.
Cleanup.
Pallet utilization.
Warehouse cube.
Transportation utilization.
Discharge labor.
Damage.
Downtime.
Annual volume.
If uncoated fabric gives you the breathability you need without unacceptable sifting, moisture exposure, product loss, or contamination, it may be the simplest and most efficient choice.
If fine product is escaping through the weave or moisture protection through the fabric is important, coated fabric or an appropriate liner system may deserve consideration.
That is the real decision.
Not:
“Coated or uncoated—which one is better?”
But:
“Which fabric construction performs better with this product, this filling system, this discharge system, and this supply chain?”
Answer that question with actual product testing, and the right fabric choice usually becomes much easier.
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