Silicon rubber recovery method: physical crushing method

Physical crushing method refers to the physical crushing of waste silicone rubber by shearing machine, double roller machine, ball mill and other equipment, which is directly used as filler after classification screening, or modified treatment (activation) after use.According to the different temperature and action mode, physical crushing method can be divided into low temperature crushing method, pinching method, polishing method and elastic deformation method, the particle surface morphology, shape and size obtained are different.

1. Used as packing directly after crushing

Silicone rubber is chemically inert, after simple physical crushing, the particle surface of the active functional group is less, it is difficult to react with the new base glue.Therefore, the products prepared by this method are mainly used as modified fillers for rubber and plastics, so as to reduce product cost, power consumption and modification.The silicone rubber particles prepared by physical crushing can be mixed with the silicone rubber mixture in any proportion.

2. Modified treatment after crushing

Ordinary rubber such as natural rubber, butylbenzene rubber, butadiene rubber, NBR, the molecular structure of C - C  C - C, its low bond energy, high chemical activity, easy to react with oxygen and sulfur, regeneration process is relatively easy.The molecular structure of silicone rubber is SI-O-SI, which has high bond energy, good heat and aging resistance, and is not easy to be oxidized. It is difficult to be recycled with the treatment method of ordinary rubber when being recycled.

In the 1980 s, the Soviet union launched the crushing waste silicone rubber recycling, with physical method first broken into granule, then particles with ethyl orthosilicate four processing into active silicone rubber powder, and mixed with the new silicone rubber vulcanization into products research, found after activation of silicone rubber powder can improve the low temperature resistance, electrical strength of the vulcanizates and physical and mechanical properties.

China has carried out the study of modified waste silicone rubber processing, such as: Wu Shaoyin all-weather aging degradation, effective crushing, grading and processing method of surface stearic acid activation, to turn the waste silicone rubber with suitable particle size (40 eyes) of the active regeneration silicone rubber powder, can be used as silicon rubber packing, has good processing properties and reinforcement effect;Weiying Zhang et al. used the mixture of hexamethylenetetramine and ferric chloride/ferrous chloride to activate and modify the waste silicone rubber and prepared epdm rubber as a filler, and found that such activators could effectively activate the waste silicone rubber and other studies.