Integral skin foam, also commonly referred to as "self-skinning” foam, is a dual-layer structure formed through a material's foaming process. This composition, similar to a loaf of bread, features a foam inner core surrounded by a solid outer crust or “skin”. While several materials can be used to produce an integral skin foam, thermoset polyurethanes can offer customizable properties to meet exact design requirements, including density, hardnesses, tensile strength, chemical resistance, and many more. Due to its adaptability, polyurethane integral skin foams can be manufactured through a cast or Reaction Injection Molding (RIM) process.
There are 3 key things to consider in your product design when determining if integral skin foam is appropriate for your application, such as:
Aesthetics
Integral skin foams can display a uniform surface that portrays either a smooth or textured finish. Because of this, product designers can eliminate painting or other secondary operations to achieve a nice aesthetic.
Performance
Integral skin foams can provide a different set of physical properties than the foam layer underneath. For example, the Coefficient of Friction (COF) of foam with an integral skin will be higher due to its smooth, shiny surface, while the exposed foam may portray a lower COF.
Non Porous
Integral skin foams can prevent any air, dust particles, or liquids from flowing through, creating a non-breathable material. Although closed-cell foams can be achieved without a skin, there is still some level of porosity left behind. To ensure the porosity of the cellular structure is completely closed, an integral skin may be recommended.
Conclusion
Integral skin foams may be a key material for products and components that require a particular aesthetic or performance. As you further explore if integral skin foams are appropriate for your product design, it is important to consider your parts function, aesthetics, and physical property requirements beforehand. If you are still uncertain if integral skin foams are appropriate for your product design, take our design tool, here, or download our material data sheet below to learn more.