Durofoam

Durofoam is a firm opaque foam with excellent compression characteristics.  Its configuration is an open cell, cross linked polyethylene and is a member of the olefin family of plastics.  This configuration allows the foam to remain at a consistent thickness over a long period of time.  This foam disperses force equally in all directions to provide comfortable localized compression.

Manufacturing
Durofoam has limited thermoforming and thermobonding characteristics.  It can be knifed, die cut, or punched.  It can be shaped by drape, vacuum, and pressure molding techniques.  The normal forming temperature range is from 300-340 F, with an optimal forming temperature of 325 F.  Durofoam has a short heat cycle and a very short working time (.5 to 1.5 minutes).  Once molded, it can be modified using localized heat.

Thermobonding is possible with most other thermobonding materials.  It is necessary for Durofoam to be at its higher forming temperatures when thermobonding.  It is critical that the surfaces of the materials be in contact quickly to avoid cooling of the foam.  Mold temperature is not critical.

Durofoam may not be solvent welded.  Most good plastic glues will mechanically bond the foam to plastics and provide medium strength bonds to metals.  Spot heat welding is not recommended.

If air holes are required to draw vacuum they should be small.  Using vacuum holes of no larger than 1/16" diameter is required to prevent marking of the foam.

Sterilization
Durofoam is not capable to be sterilized using standard techniques.

Precautions
Durofoam is a combustible material and therefore should be stored in a cool dry area.  The flash point is 640 F.  Because it is a petroleum derivative, it gives off a heavy black toxic smoke that is dangerous to inhale and difficult to see through.  This material is not effected in most outdoor applications.  When used in extended close contact with the skin, it should cover with a non allergenic material.

Applications
Applications of this material are vast.  It can be used anytime long term compressive forces are to be applied.  It is a preferred material in uses, such as, pads, splints, prosthetic compression pads and podiatric applications.  It is a good substitute in areas where compressive forces have caused compacting of previous foam materials.  It can be laminated in combination with less dense foams to provide superior force dispersion while still sustaining firm support, as in the treatment of diabetic feet.  When laminated with a thin layer of Thermofoam, it obtains good characteristics of support and high comfort while supplying a hypoallergenic surface for prolonged term skin contact.

Sheet Chart
Durofoam is a rigid, white, open cell, cross-linked polyethylene foam with limited thermoformability and thermobondability, but excellent compression and skivability characteristics.  The material retains thickness after extended use, but allows localized compression.