Foam rubber has closed or open cells and it is also everything which has a specific weight under 1,00 gr/cm3.

The main characteristics are softness,elasticity,elastic recovery,compression until 0 mm abd it usually used as air,powder and water tight gasket.
NBR/PVC系列发泡橡胶产品型号有：
材料型号 开孔/闭孔 颜色 密度kg/m³ 温度℃ 邵氏硬度 防火性能
POR.302/T， 闭孔 黑 200 -40~100 55 UL 94-HF1
POR.302/T-E， 闭孔 黑 150 -20~100 50 UL 94-HBF
251 BG， 闭孔 米色/白 170 -20~90 60 /
251 GR， 闭孔 灰 250 -20~90 65 /
POR.251/NE HD， 闭孔 黑色 300 -20~90 80 /