Zotefoams Look at Their Range of Military Foams

Zotefoams plc

Military Foam

In Military environments protective foam cushioning must withstand repeated abuse and still be able to perform its intended function. The physical performance of a foam and its repeatability depends on its density along with its cell size, structure and consistency. The majority of MOD Defence Standards acknowledge this by specifying density specifically and starting with the premise that military foam “shall have a uniform closed cell structure.”

Not all foams have a regular cell structure as can be seen by the comparative micrographs in Figs 1 & 2. Foams expanded by the Zotefoams’ nitrogen expansion process (Plastazote and Evazote) have a more regular and consistent cell structure than alternative chemically blown foams. Typically a stipulated physical performance requirement can be achieved by a lighter (less dense) grade of Zotefoams material. Weight for weight (or density for density) foams from Zotefoams have higher tensile strength, higher compressive stress (stronger and stiffer under strain), greater tear strength and higher resistance to compression set than chemically blown foams. These physical attributes all add up to higher levels of protection performance and durability in the field.

Military Foam - Consistent Cell Structure Military Foam - Irregular Cell Structure

Advanced Military Packaging

Advanced Military Packaging - Rifle CaseA less obvious requirement for military foams lies in timescales. In commercial single trip applications the life of a piece of protective foam packaging is typically measured in days or weeks and with the advent of JIT (just in time) inventory strategy the life requirement has been reduced in recent years. Not so with military foam.

In many military applications the packed item is immediately committed to long term storage. Munitions and firearms are stockpiled for use “in the event of war” and are quality checked periodically. Such items must not deteriorate, even during very long term storage, and must be ready to perform immediately when or if needed.

Corrosion is always a major concern and some MOD Def Standards go as far as specifying “silver staining performance” with which foams must comply. Polyethylene, and for that matter EVA are relatively inert polymers and will not cause staining and corrosion. In chemically blown foams the potential source of staining and corrosion tends to be from blowing agent residues.

The blowing agent used to expand Plastazote and Evazote is pure Nitrogen, which has no corrosive potential, making these materials an ideal advanced military packaging material for long term protection.

Low Odour Materials

paveway_2Anyone that has witnessed foams expanded chemically by the decomposition of an azodicarbonamide blowing agent will have noticed its pungent ammonia odour. In confined spaces such an odour would quickly become oppressive. For this reason, some MOD Def Standards call for a material “without objectionable odour”.

No foams manufactured by the unique Zotefoams method have objectionable odours, in fact they are classified as low odour materials. They are also free of Volatile organic compounds (VOCs)…gases or vapours that could have adverse health effects.

Mil Spec Material

It is sometimes confusing and a little difficult to find a particular foam grade that meets with specific military requirements. This interchange can be of some help in sourcing the right mil spec material.

Standard

Description

MOD Grade

Product

DStan 81-116/3 Type GP "Expanded Polyethylene
Sheet - General Purpose”
Grade A
Grade B
Grade C
Plastazote LD24
Plastazote LD33
Plastazote LD45
DStan 81-116/3 Type QX "Expanded Polyethylene
Sheet - Explosives Compatible"
Grade A
Grade B
Grade C
Plastazote LD24
Plastazote LD33
Plastazote LD45
DStan 81-124/2 Type QX "Expanded Polyethylene
Sheet - Mouldings and
Explosives Compatible"
  Plastazote LD33
DStan 93-101 "Expanded Polyethylene
Sheet - High Density for
General Purpose”
  Plastazote PK80
DStan 81-125/3 “Electrostatic Conductive
Foam Sheet”
  Plastazote LD50CN
DStan 93-117 “Static Dissipative Low
Density. Polyethylene Foam”
  Plastazote LD40SD
DStan 81-119/3 “Cross-linked Expanded
Ethylene-vinyl Acetate
Sheets and Mouldings”
  Evazote EV50
Evazote VA25

This list is provided as a guideline and summary If you have an inquiry regarding any material not listed in these tables or whether a certain material meets a standard that is not indicated in this table please contact the Zotefoams Technical Support Team +44 (0) 20 8664 1600

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