Greaseproof, Waterproof Kraft-Polyethylene Barrier Material Built to MIL-PRF-121
Military Packaging supplies kraft and polyethylene barrier material built to MIL-PRF-121, the military specification for greaseproof, waterproof, flexible barrier material. A kraft paper laminated with polyethylene, it wraps and lines packages to keep water and grease out, protecting preservative-coated parts and general hardware through handling and storage. Order it as sheeting, wraps, or heat-sealable bags, on its own or built into a complete preservation system we design around your equipment.
MIL-PRF-121 is the military specification for greaseproof, waterproof, flexible barrier material. It defines a kraft paper laminated with polyethylene, so the material combines the strength of kraft with the waterproof, heat-sealable qualities of a poly film.
That construction makes it a rugged, everyday barrier. It keeps liquid water and grease out, resists tearing, and heat-seals into wraps, liners, and bags, which is why it shows up across military packaging as a workhorse waterproof material.
We supply MIL-PRF-121 material in the grades your program requires, as sheeting, wraps, or bags. When a drawing calls for MIL-PRF-121, this is the material it means.
Every MIL-PRF-121 material we supply protects packages from water and grease:
The specification defines what makes a compliant greaseproof, waterproof barrier:
MIL-PRF-121 comes in grades that set the material’s durability. A reinforced grade adds a scrim between the kraft and poly layers, giving extra tear and puncture resistance for rough handling and heavier wraps, while a non-reinforced grade is lighter and economical for less demanding jobs.
We help you read the callout and supply the grade your drawing requires, or recommend one when the choice is open. Send us the spec and the part, and we will confirm the right MIL-PRF-121 material for the job.
MIL-PRF-121 material protects packages across a defense shipment:
MIL-PRF-121 material protects the hardware these sectors ship and store every day:
A few factors point you to the right MIL-PRF-121 material. Weigh these, or send us the part and we will recommend one:
MIL-PRF-121 material is the waterproof layer in a package. It wraps the part, lines the box, or bags the hardware, keeping liquid water and grease from reaching the contents. The outer container carries the load from there.
Sourced as one system, the material is matched to the part it protects and the box it fits, so hardware stays waterproofed and greaseproofed from the moment you wrap it to the moment it is opened.
It helps to know what MIL-PRF-121 does and does not do. It is waterproof, blocking liquid water, and greaseproof, resisting oils and preservative compounds, which makes it ideal for wrapping and lining. It is not a water-vapor barrier, so it does not hold a dry environment the way foil does.
That distinction guides the choice. For waterproof protection and greasy parts, MIL-PRF-121 is the right, economical material, and for a sealed, watervaporproof environment with desiccant, you step up to a foil barrier such as MIL-PRF-131. We help you pick the right one for the job.
Many metal parts are preserved with oils or corrosion-preventive compounds before packaging, and an ordinary paper would soak through. MIL-PRF-121 is greaseproof, so it wraps oily and coated parts cleanly, holding the preservative on the part and off everything else in the package.
That makes it a natural match for machined metals, tools, and hardware protected with a preservative coating. Tell us how your parts are preserved, and we will supply the MIL-PRF-121 material to wrap them.
Reading a barrier callout and supplying the right material is what we do. Our team helps buyers and packaging engineers match the MIL-PRF-121 grade and form to the part, and meet the preservation spec that governs the shipment.
Send us the part, the threat, and any spec callouts, and we will recommend the right MIL-PRF-121 material and quote it, so your hardware ships waterproofed and compliant from the first shipment.
Every program defines its protection a little differently, and we build to yours. When your documentation names a MIL-PRF-121 grade, a form, or a preservation method, we match it exactly. When the choice is open, we recommend the material that fits the part and the conditions.
That flexibility means your packaging satisfies the spec and protects the part in practice, with no gap between the two.
MIL-PRF-121 material does its best work as part of a full system. We wrap the part in the waterproof material, add a barrier bag and desiccant where a vapor barrier is needed, cushion against shock, and enclose the pack in a box or crate rated for the journey. Sourced together, every layer protects the part against water, grease, and impact alike.
We supply material that meets MIL-PRF-121 for the barrier and MIL-DTL-117 for finished bags, and we build it into packaging that satisfies your spec. Where your drawing cites the grade or a waterproof method under MIL-STD-2073, we match it.
Where the drawing leaves a choice, we recommend the grade and form that best protect your part. Either way, you get waterproof protection you can ship on.
Tell us what you are protecting, how it is preserved, the form you need, and any spec callouts, and we will recommend the right MIL-PRF-121 grade and form.
We supply MIL-PRF-121 as sheeting, wraps, and heat-sealable bags, on its own or as part of a complete preservation system, with availability and turnaround confirmed in your quote.
We supply MIL-PRF-121 material in the grade and form each job needs, and we know how to build it into a compliant system alongside the right vapor barrier when a part needs one.
That combination keeps hardware waterproofed, coated parts clean, and shipments protected after handling, shipping, and long storage.
MIL-PRF-121 is the military specification for greaseproof, waterproof, flexible barrier material. It defines a kraft paper laminated with polyethylene, used to wrap, line, and bag packages so water and grease stay out.
It is kraft paper laminated with polyethylene, and in reinforced grades it adds a scrim between the layers for extra strength. The kraft gives it durability and the poly makes it waterproof and heat-sealable.
It is waterproof, blocking liquid water, and greaseproof, but it is not a water-vapor barrier, so it does not hold a dry environment on its own. For a sealed, watervaporproof pack with desiccant, you step up to a foil barrier like MIL-PRF-131. We help you choose.
The reinforced grade adds a scrim for extra tear and puncture resistance, which suits rough handling and heavier wraps. The non-reinforced grade is lighter and economical for less demanding jobs. We match the grade to the handling.
Yes. It is greaseproof, so it wraps oily and preservative-coated parts cleanly, holding the coating on the part and off the rest of the package. That makes it a good match for preserved machined metals and tools.
Yes. MIL-B-121 was the older designation for the same barrier material specification, now MIL-PRF-121. If your drawing still calls out MIL-B-121, we supply the current MIL-PRF-121 material to meet it.
Tell us what you are protecting and how it is preserved, and we will recommend the right MIL-PRF-121 material, then get you a quote.
