Dunnage Bag Suppliers

Dunnage Bags for Container, Rail and Trailer Load Securement

Shanghai We Pack Co., Ltd. is a Dunnage Bag manufacturer in China, supplying kraft paper, woven PP and PVC air bags together with the inflators that fill them. We build to the void rather than to a catalogue default: bag width, bag length, valve position and working pressure are set from the actual gap between cargo and the transport mode it travels in.

Founded in 2019 as a subsidiary of Shanghai Dreammao Packaging Technology Co., Ltd., we operate a 10,000 m² facility with 9 production lines, dedicated R&D, testing and quality control teams, and dunnage air bag output above 30,000 pieces per day. The range serves one-way export loads as well as reusable multi-trip programmes for rail and ocean freight.

The Dunnage Bag Range

Three constructions cover the majority of bracing and blocking requirements. Each is produced in-house, so material, valve and print decisions stay inside one supply chain instead of being split across converters.

Where Each Bag Type Fits

• Kraft paper — the default for mixed dry cargo where the load is braced once and discharged. The paper body absorbs minor surface irregularities and the PE barrier keeps the bag stable through humid sea transit.
• Woven PP — chosen when the same bags are recovered, folded and reused, or when rail impact and long-haul vibration demand higher abrasion resistance. AAR level selection is matched to the cargo mass and the rail or road environment.
• PVC — used where air retention matters most: chilled and frozen cargo, high-value electronics, and routes with large day-night temperature swings that stress the bag wall.
• Combined loads — dunnage bags are frequently specified alongside edge protection, slip sheets and anti-slip paper so that the void is filled and the unit load itself is stabilised.

Critical Specifications We Confirm Before Production

A dunnage bag only performs if it matches the void it is placed in. These are the variables we lock down at quotation stage, because each one changes the bag construction or the inflation instruction.

• Void width — the measured gap between cargo faces or between cargo and container wall. Bag width is selected so the inflated bag bridges the gap and stays in contact with both surfaces without being over-inflated.
• Void height and bag length — the bag should cover the full height of the void so the bracing force is distributed rather than concentrated.
• Working pressure and burst margin — set by bag construction and the applicable AAR level. Paper bags generally run at lower working pressures than woven PP or PVC bags.
• Valve type and position — single or double storm valve, positioned for the inflation angle available inside the container.
• Cargo mass and centre of gravity — determines how many bags are needed per row and whether bracing is combined with strapping or lashing.
• Transport mode — ocean, rail, road or multimodal, since rail impact profiles are the most demanding.

Engineering Value: From Void Measurement to Loading Plan

Our starting point is the loading plan, not the bag. We take the cargo dimensions, stacking pattern and container or wagon type, calculate the residual voids, and then assign bag sizes and quantities to each void. That calculation is what allows a load to be filled to the door without leaving unbraced gaps.

Because the bag is sized to the void, container space that would otherwise be sacrificed to over-bracing stays usable. Customers working with us on this basis typically reduce total logistics costs by 15–30% while keeping the load stable in transit.

Manufacturing, Testing and Compliance Evidence

Production runs across 9 lines in a 10,000 m² plant, with workshops organised by process — material handling, forming, cutting, welding, assembly and packaging. Standardised process control from raw material to finished goods is what keeps bag dimensions and valve sealing repeatable across repeat orders.

• In-house laboratory and quality centre for stress and pressure testing of finished bags.
• Third-party verification through SGS and TUV, with test reports issued per batch or per project.
• AAR level testing for PP dunnage bags, covering Level 0–6 configurations.
• ISO 9001 management system; kraft paper bags supplied RoHS compliant and recyclable.
• Documentation available with shipment: test reports, material declarations and packing lists.

Configuration Options and OEM / ODM Support

Customisation covers size, load capacity, material grade, valve type and printed branding. We develop bags from customer drawings or physical samples, and the minimum order quantity is 100 pieces, which supports trial runs before a programme scales.

Typical configuration decisions include bag width and length, paper ply count or fabric weight, liner specification, valve count, print layout, and whether the bag is supplied flat-packed for manual handling or bundled for mechanised loading.

Inflators, Tools and Complementary Protection

Dunnage bags are only as good as the inflation equipment used with them. We supply a complete inflator ecosystem, from manual air guns through to cordless intelligent inflators that regulate pressure at the bag, so the working pressure in the loading plan is the pressure actually achieved on the dock.

Because we also manufacture paper corner protectors, slip sheets, anti-slip paper, stretch film, packing straps and strapping tools, a single shipment can carry the full protection package for a container — void filling, edge protection, unit-load stability and load restraint — matched to the same loading plan.

Information We Use to Configure Your Solution

Send the following and we will return a sized bag specification, quantity per container or wagon, inflation instruction and quotation.

• Cargo type, unit dimensions, weight per unit and stacking pattern.
• Container, trailer or railcar type and internal dimensions.
• Measured void widths and void heights, or a loading sketch.
• Transport mode, route and expected transit duration.
• Whether bags are single-trip or recovered for reuse.
• Target AAR level, compliance requirements or customer specification.
• Printing artwork, packaging preference and required delivery schedule.

Frequently Asked Questions

Which dunnage bag type suits my cargo?

Kraft paper bags cover general dry cargo and one-way export loads. Woven PP bags suit heavy-duty, multi-trip and rail applications where abrasion resistance and AAR level certification matter. PVC bags are specified for moisture-sensitive and cold chain cargo where air retention over a long transit is the priority.

Can you produce bags to our own dimensions and print?

Yes. We work from drawings or samples under OEM / ODM arrangements, covering bag width, length, ply or fabric construction, liner, valve configuration and printed branding. Minimum order quantity is 100 pieces.

How is bag performance verified?

Finished bags are stress and pressure tested in our own laboratory, and batch or project testing is carried out by third-party institutions including SGS and TUV. PP dunnage bags are tested to AAR levels, and test reports are issued with the shipment.

Do you supply the inflation equipment as well?

We supply manual air guns through to cordless intelligent inflators, matched to the bag type and working pressure in the loading plan. This keeps the inflation step consistent across shifts and loading crews.

What is the production capacity and delivery position?

Dunnage air bag output exceeds 30,000 pieces per day across 9 production lines, which supports both frequent customisation and large repeat programmes. The plant sits close to Shanghai Port and Pudong International Airport, and we work on EXW, FOB, CIF and DDP terms.

Can dunnage bags be combined with other protection products in one order?

Yes. Paper corner protectors, slip sheets, anti-slip paper, stretch film, packing straps and strapping tools are produced within the same group, so a complete container protection package can be planned, manufactured and shipped together.