The Chemistry of Foam Insoles and What It Means for Footwear
Here’s a quick primer on the chemistry of these foam types:
Open-Cell Foam: In open-cell foams, many of the microscopic cells are connected, allowing air and moisture to circulate and compress more easily, often resulting in softer cushioning, greater breathability, and a more comfortable underfoot feel.
Closed-Cell Foams: With closed-cell foams, gasses are trapped in individual cells, which can make them more rigid, water-resistant, and durable under long-term compression.
Polyurethane (PU) Foam: PU foams can be open cell or poured, but either way, PU foams are versatile and can be formulated across a wide range of densities, firmnesses, and resilience levels. PU tends to provide reliable cushioning and shock absorption, and can be engineered for durability or softness depending on the footwear.
EVA Foam: Ethylene-vinyl acetate (EVA) is a lighter-weight, closed-cell foam that is widely used in athletic midsoles and insoles. EVA provides good cushioning, impact absorption, and shape retention.
INSITE’s three foams capitalize on the benefits of these foam types, allowing footwear designers to find the right foam for their design goals. Let’s dig into our three insole foams and how they deliver on the properties of their foam chemistry.