The industry distinction between sponges is based on density. The density of the sponge is kg/m3. It is the weight of each cubic meter of sponge. Density is an important indicator of matter, and the density of the sponge is high, indicating that the gap inside is small and the quality is greater. For example: 40 density means that the weight of a cubic meter sponge is 40 kg, and the density of 50 is 50 kg per cubic meter. Generally speaking, the sponge with high density is also high in hardness, but it is not excluded that some high-density sponges will add super soft auxiliaries to make the sponge super soft, which is used for sound absorbing cotton, sofa cushion and soft bag material. Medium and low density sponges are used as general protective materials.
The degree of hardness of the sponge of the same density is not necessarily the same. Generally, the density of the sponge for the sofa cushion is about 35, and it has soft, hard, super soft and other specifications. The mattress is generally about 22 feet. The so-called high-density sponge is a term commonly used by salespeople when introducing goods. According to the explanation of the relevant state departments, the density is ≥45 for high density, the medium density is <45 and >18, and the low density is <18.