Material Terminology

Help us help you by speaking the same language. Below we have listed some terms that will assist us in communicating with you over material choices and specifications.

Bottoming Out- This happens when a gel is subjected to a load and the gel is no longer evenly distributed under the load, thus no longer supporting the load.

Closed cell- Used to describe the cell structure, or bubbles, in foams.  Closed cell foam has closed cells making the foam denser and usually more impervious to the environment.

Compression load deflection- The force required to compress a material a given distance.

Compression set- The amount of deformation which a material retains after compressive stress is released, usually given as a percent of the original dimensions.

Cone penetration- A method used to show the hardness of a very soft gel by pressing a cone into the material and measuring the depth of its penetration.

Density- The mass per a unit of volume.

Durometer- A testing method used to show the hardness of a gel, in different scales. It measures the depth of an indentation in the material created by a given force on a standardized presser foot. (see table)

Elastomer- A polymer with the ability to return to it original shape after being deformed by a load.

Elongation- The amount of deflection a material can withstand without failing while being stretched, usually given as a percent of the original dimensions.

Hydrophilic- The aptitude of a material to absorb water.

Hydrophobic- The aptitude of a material to repel water.

Indentation force deflection- A test method to determine load bearing capacity, meaning the firmness or stiffness, of a foam at a given percentage of deflection

Knit- When thread is looped together to form a uniform fabric, also known as stitching

Mil- One thousandth of an inch.

Open cell- Used to describe the cell structure in foam, open cell foam has open cells making the foam less dense than closed cell.

Polyester (gels, films, foams)- A polymer consisting mostly of carbon and oxygen with great ability to resist chemicals

Polyether (gels, films, foams)- A polymer consisting mostly of  carbon an d hydrogen with great ability to resist water

Polymer- Is a molecule comprised of repeating structural units usually comprised mainly of carbon.

PU- Common abbreviation for polyurethane, a polymer.

Resiliency- The ability of a material to absorb energy while being deformed, and unloading the energy and return to its original state.

Shore durometer scale A- Used for soft rubbers, elastomers, and plastics (see comparison chart)

Shore durometer scale OO-Used for foams, and gels (see comparison chart)

Shore durometer scale OOO- Used for very soft gels (see comparison chart)

Specific gravity- The ratio of a substances density to the density of water.  If the specific gravity is greater than 1 it is denser than water.

Tack- The measurement of the ability of an adhesive to adhere to another surface.

Tear strength- The force required to rip, or fail a material latitudinally.

Tensile strength- The force required to fail a material longitudinally.

Thermoplastic- A polymer that when heated turns to liquid, and when cooled returns to a solid.  This material can then be melted repeatedly.

Thermoset- A polymer that irreversibly cures, either by heat or by chemical reaction.   

TPE- Abbreviation for thermoplastic elastomer.

TPU- Abbreviation for thermoplastic polyurethane.

UV- Stands for ultraviolet light, which could either negatively or positively, effect polymers.

Viscoelastic- A material that has both viscous and elastic properties.  Viscous materials resist shear flow and strain linearly with time.  Elastic materials can return to original state once a force is removed.

Warp- Threads of a weave that run lengthwise against the weft

Weave- When threads are woven together in a criss-cross pattern often measured in the number of threads per inch.

Weft- Threads of the weave that run across from side to side, supporting the warp which run lengthwise.