Polyester and Polyether are basically produced the same way, but they are manufactured with different chemicals. Basically a collection of two chemicals and water are mixed together and heated to create liquid Polyurethane. When the ingredients are combined there is a strong chemical reaction where the liquid Polyurethane begins to rise like bread in an oven. In a matter of minutes it reaches its maximum height. The height is not always consistent from one run to the next. When the material cools, it has a raised center that resembles a bun of bread. This is why the bulk material is referred to as a Bun of Urethane foam. Buns are generally poured at least 60' long. The width is commonly 82" and the height can vary from 24" to 48", and sometimes even more! The buns are typically cut to smaller more manageable lengths prior to fabricating.
Polyester and Polyether Families
Polyurethane foam for packaging purposes is normally a light weight to medium density material with a more than average IFD. This gives you a less expensive and a firmer foam that provides excellent protection for the most fragile items that are packaged.
PU foam is a great material that absorbs shock and compresses quickly to prevent the packaged product from coming to an abrupt stop. This also requires more material and space to slow the products acceleration to prevent any fragile inner components of the package from being damaged.
Polyether Family
Bedding is the main industry that PU material is used for. There is a wide variety of PU foam, which include multiple combinations of densities and IFD's. This creates many different feels that make the bed comfortable to lay on.
Polyether Family
Upholstery foam normally has a higher density and a lower IFD which creates a heavier and rubberish feel that makes seats comfortable to sit on. Lowering the density and IFD will create a very soft material which is great for seat backs. It is always nice to lean back into a soft and cushy seat!