Liquid silicone rubber is more safe and environmentally friendly, and can fully meet the food grade requirements. According to the position of functional groups (i.e. cross-linking points) contained in the molecular structure, liquid rubber with functional groups is often divided into two categories: one is remote claw liquid rubber with functional groups at both ends of the molecular structure; The other is the random distribution of active functional groups in the main chain, that is, those with functional groups in the molecular structure are called non telechelic liquid rubber. Of course, there are also those with both intermediate functional groups and end group functional groups. At present, the focus is on the research of remote claw liquid rubber. For liquid rubber, chain extenders or crosslinkers with appropriate functional groups should be selected according to the active functional groups contained in it.