Skip to product information
1 of 5

MIL PRF 131 K Class Aluminium Foil VAL131HS High Strength Military Packaging Rolls + Valcross®

MIL PRF 131 K Class Aluminium Foil VAL131HS High Strength Military Packaging Rolls + Valcross®

Regular price £796.65 GBP
Regular price Sale price £796.65 GBP
Limited Offer Call for quote

49 in stock

This Military Packaging is an aluminium foil & PE construction with the addition of a high strength Valcross® membrane layer.

With the addition of Valcross® these flexible barrier materials feature an enhanced tear and puncture resistance as well as excellent moisture barrier properties.

VAL59HS™ is an ideal choice for large or awkwardly sized objects, particularly those with sharp edges.

Conforms with DEF STAN 81-147 (formerly DEF STAN 81-75) & MIL-PRF-131 K Class 1.

We hold pre cut 1.0mtr, 1.25mtr & 1.50 mtr rolls in stock. Standard lengths are 200 linear mtr but a custom slit and rewind service is available.

The tough construction of this MIL PRF 131 K Class 1 aluminium foil make it the ideal choice for demanding export and asset preservation/storage projects.

The combination of complementary materials in this mil spec packaging result in an effective moisture barrier that protects goods during transport and storage.

The tear and breaking strength is the highest in our range. Still it retains the very low moisture vapour transmission rate of 0.3g/m2 per 24 hours. This is one of a list of impressive characteristics seen on the data sheet of this material.

The high performance nature of this extends to the inclusion of Valcross® in the laminate. This gives optimal strength whilst retaining excellent flexibility.

This barrier foil is available in several different widths supplied in a 200mtr log packaging roll. The user can cut to the desired dimensions allowing the component to be heat sealed and vacuum packed for for it’s journey.

Using MIL-PRF-131 K Spec Bags

This type of Aluminium foil can be converted into liners flat bags & pouch packaging to suit components and precision parts.

It is ideal for use in heavy machinery transport/storage projects. It also meets the standard EU and BIR guidelines as well as MIL PRF 131 K class 1.

  • NF H 00 310 CLASS IV approved.
  • DEF STAN 81-75/2 – TYPE 1 CLASS A approved.

MIL PRF 131 K Class 1 Handling

Requires Heat sealing with a compound aluminium foil sealer. Set to 210°c at 5 bars for 2-3 seconds.

The suitable operating temperatures for this material are between -40°C to +70°C.

For optimal conditions we recommend you use this barrier foil in conjunction with desiccant. This will absorb excess moisture in transit.

For more information on how to calculate desiccant requirements please visit our desiccant estimate page.

Warning – Please note this material is intended to be used only by suitably trained professionals.

The Mil PRF 131 K performance specifications is specified by the US government to apply to barrier materials that are:

  • Water vapour proof
  • Grease proof
  • Flexible
  • Heat Seal able

These military specification barrier materials must feature the above characteristics to be suitable for use as military packaging.

Technical Data

Constructed of micron 12чm PET, 9чm Alu, 70gsm Blue Crossed Polyethylene Valcross® Material code VAL59HS.

Delivery Time

Dependent on quantities and format ordered. Log & jumbo foil rolls available from stock.

Product Specifications

What is Mil - PRF - 131 Class 1?
Class 1 Mil - PRF - 131 material is a robust laminate barrier (made of foil materials) known for its water-vapour-proof qualities. Primarily utilised in crafting shrouds and barrier bags with corrosion prevention, this military-grade material adheres to stringent specifications mandated by the Dept of Defence for all its branches and agencies. Its compliance guarantees top-tier traceability and protection. The 3D-Barrier-Bags Inc. Boasts three materials sanctioned by the US QPD (Qualified Products Database) Naval Labs for Class 1 Mil - PRF - 131K applications.

As of to date (April 2022), the standard/specification has transitioned to Class 1 Mil - PRF - 131L. While retaining all qualifications of Class 1 Mil - PRF - 131K, the US QPD Naval Labs updated the standard to reflect the exclusion of Class 2 materials.

These versatile materials lend themselves to tailored barrier bag solutions, perfectly conforming to your product specifications with efficiency. Whether in need of customised bags or rolls for smaller tasks, our offerings are adaptable. The inclusion of a Polyethylene inner layer enables easy sealing using handheld heat sealers, particularly those equipped with straight bar sealers delivering heat evenly (bottom to top). This facilitates the conversion of the material into modified Barrier bags with vapour protection against corrosion, including compliance with the Mil DTL-117 requirement.

Mil - PRF – 131 Performance Specification
What sets Mil - PRF - 131 raw material apart as the premier choice for safeguarding your products? These raw materials exhibit exceptional puncture and tear resistance, coupled with unparalleled barrier properties. Consequently, materials formil - PRF - 131 prove optimal for safeguarding sizeable items against moisture vapour damage, oxidation, corrosion, and external contaminants, be it during transit or storage.

The rigorous testing regimen mandated for Mil - PRF - 131 resources to attain registration with the US QPD Naval Labs ensures their reliability. All testing parameters must precisely match those of the final product, guaranteeing no unauthorised alterations that could jeopardise product integrity. Any deviation from the experimented material may lead to rejection and removal from the QPD. Testing procedures are conducted in an environment with 50 relative humidity ± 5% and a 73 ± 3 ℉ temperature.

For Mil - PRF - 131 supplies to meet military specifications, they must successfully navigate stringent tests, including:

  • Seam Fabrication and Strength:
    • Ensuring no leakage or separation at the double seam under testing temperatures between 100℉ and 160℉.
    • Verifying no separation/leakage at the double seam when sealed prior to temperature aging at 160℉ (under the same test requirements).
    • Confirming no leakage/separation at the double seam when sealed after aging at temperature 160℉ (under the same test restrictions).
  • Transmission Rate of Water Vapour (WVTR)
  • Breaking Strength
  • Blocking, Curl, and Puncture Resistance
  • Contact Corrosivity
  • Delamination/Oil Resistance
  • Water Resistance

Once the testing for Mil - PRF - 131 compliance is cleared, additional requirements must still be met to satisfy military specifications. Every aspect, from the colour of the printed text to the way the material is utilised—whether in roll or bag form—must align with stipulated criteria for full compliance with military standards. This meticulous adherence to every specification ensures the material's suitability for military applications and underscores its reliability in safeguarding critical assets.
Mil - PRF - 131 Class 1 materials necessitate the inclusion of the following text printed in lustreless red:

  • Nomenclature
  • Material Code
  • Manufacturer
  • Lot Number
  • Transmission Rate-Moisture
  • Batch Number
  • Sealing Guidelines

Mil – prf – 131k performance standards/specifications
(This standard is a snippet of a complete list provided by the usa government. For the current and complete document, you can visit the website of usa department of defense

Not measurement precision

  • Mil - prf - 131k (previously mil-b-131h, august 18, 2005)
  • Replacing mil - prf - 131j on august 25, 1998

Performance specification
Greaseproof, barrier materials, flexible, water vapour proof, heat-sealable
1. Scope
This specification encompasses the criteria for greaseproof, flexible barrier, heat-sealable materials characterised by many properties, including low transmission of water vapour. This criterion is made to enhance packaging intended for military use.

Requirements- Qualification
Prior to contract award, the barrier/packaging materials delivered under this standard/specification must be authorised via the qualifying procedure for inclusion on the appropriate eligible product list.

  • Material - Barrier components must be constructed using substances and methods that meet the performance parameters of this specification/standard.
  • Construction - Barrier materials shall be created from any number of plies in any method that ensures they meet the performance guidelines of this standard. Butting elements for assemblies or finished goods is forbidden unless in a path parallel to the rolling orientations. When butting is performed on the completed item or any of its layers, sections must be clearly marked with colourful indicators to avoid using that piece of the roll.
  • Splices - Every single roll shall have no more than three splices (or four sections). The length of each roll measures at least 45 yards. Even distribution within the width is a strict requirement for the splices and remains unbroken during the unrolling process. Each roll must have clear markings on both ends, using a coloured label. The colour must indicate the presence of splices. Barrier material in flat sheets must not contain any splices.
  • Form - The barrier components shall be delivered in flat sheets or rolls, as indicated in the agreement or request.

Rolls must be 36 inches wide, with a tolerance between 1/4 and 1/8 inch, except if specified differently. The minimum length of roll components must be at least 200 yards. Moreover, individual rolls must reach a length of at least 195 yards. The material must be consistently coiled on nonreturnable cores with an internal diameter of at least 3 inches and a tolerance of 1/8 inch plus. The length of the core must correspond to the width of the roll components with a tolerance of + 1/8 inch, assuring stiffness to prevent deformation during use and shipping. Each roll must be properly bound to avoid unwinding.

  • Sheets - When flat sheets are defined, their width and length must meet the standards established by the purchasing activity. Tolerances for sheet measurements are +¼ inch or -1/8 inch except otherwise mentioned. Flat sheets should be piled consistently for ease of storage and handling.
  • Sealing - Barrier materials must be heat sealed under the manufacturer's suggested conditions. These parameters should be consistent with typical manufacturing process sealing procedures, utilising easily accessible sealing machinery and assuring a commercially viable production period. When sealed according to the manufacturer's instructions, the material should not show any delamination at the heat-sealed area. Each roll or package of barrier material must have a tag attached to the core of the rolls or inserted into the package of sheets that contains instructions for heat sealing using rotary, band, and jaw-type sealing equipment. This tag or sheet must be clearly visible when the unit package is opened.
  • Material identification - Use water-resistant ink to clearly and legibly mark important details such as the requirement number, manufacturer's name, class, manufacturer's designation, production (year and month), and lot number. These labels should also include heat-sealing circumstances such as pressure, temperature, and dwell time) on the backing surface of the material. These should be lusterless red, continuous horizontal, and two inches apart. An entire set of labels should be visible every 18 inches all through the entirety of the roll, with characters and numbers no smaller than 1/8 inch.
  • Performance requirements - Barrier materials must meet the standards stated in Table I.
  • Workmanship - Barrier material surfaces must be free of foreign materials, and edges should be carefully trimmed and cut of any selvage. The material should be free of splits, cuts, holes, wrinkles, sharp creases, and other flaws.


Click here for constant heat sealers

View full details