What is relationship between density and hardness of EVA foam tape?

EVA foam tape is a material that is widely used in scenarios such as sealing, shockproofing, cushioning, and pasting. Its properties are affected by a number of factors, among which the relationship between density and hardness is particularly critical. Understanding the connection between the two can help you choose the right product for your application.

Density usually refers to the mass per unit volume in kg/m³ or g/cm³. In EVA foam, the higher the density, the fewer the cells inside the material and the tighter the structure. Hardness reflects the ability of a material to resist compression or deformation, and is generally expressed in Shore hardness. Generally speaking, the higher the density, the greater the hardness of the foam because of its internal cell wall thickness, low elasticity, and slow rebound after compression.

But density is not completely linear with hardness. For example, foams may exhibit higher hardness even at lower densities in certain formulations or foaming processes. This is often the case in products with special fillers or adjusted crosslinker ratios. Therefore, in the selection process, the hardness performance cannot be judged solely by density.

For occasions that require good cushioning properties, such as electronic packaging or automotive interiors, it is recommended to use EVA foam tape with medium density and moderate hardness; For applications that require support or structural stability, such as building gap sealing or fixing components, high-density and high-hardness products are more suitable.   Currently, EVA foam strip's hardness is usually 38-42,50-55 shore, 

In summary, the density of EVA foam tape is closely related to hardness, but the specific performance needs to be considered in combination with the formula and application scenarios. Reasonable selection can give full play to its performance advantages.