The silicone rubber polymer is a chain structure composed of Si-O bonds,
and its main component is a linear polysiloxane. The Si-O-Si bond is
the main chain of its structure, which spirals to cancel the polarity of
the silicon-oxygen bonds, and the side chains are generally low-polar
or non-polar groups, so the polarity of the entire macromolecule is very
low. The silicone rubber exhibits hydrophobicity, oxidation resistance
and aging resistance. In addition, the Si-O bond in the main chain and
the Si-C bond in the side chain are similar to the ionic bond, and do
not undergo cracking, oxidation, etc. at normal use temperatures (below
250 ° C), so they have excellent resistance. Heat, can be used as
medical devices, artificial organs and drug delivery systems, and has
good biocompatibility to the human body. Due to the small intermolecular
force of silicone rubber, its film has better gas permeability than
ordinary rubber and plastic waxing film, and has strong selectivity to
different air permeability, such as gas exchange film medical supplies
and artificial organs in vivo. Wait.
The design, production and sales of medical silicone rubber products
are basically the same as ordinary silicone rubber products, but the
requirements for materials, manufacturing processes, processing
equipment, production environment and product packaging are much higher
than ordinary products. The silicone rubber products in the body are
used for the body, and the formula is simple to be used. The auxiliary
materials which are not added are not added as much as possible, and the
various matching materials are required to be pure, and it is strictly
forbidden to add toxic substances. The main reinforcing agent commonly
used is white carbon black, and the vulcanizing agent is generally a
peroxide such as 2,4-dichloroperoxybenzene (DCBP) and
2,5-dimethyl-2,5-di-tert-butyl. In order to facilitate the operation and
prevent the tendency of structuring during the processing of oxidized
hexane (DBPMH), a small amount of processing aids such as hydroxy
silicone oil and alkoxysilane are often added. For example, molded
vulcanized silicone rubber formula: methyl vinyl silicone rubber 100;
silica gel with white carbon black A-2 45 ~ 50; DBPMH 0.5 ~ 1 ; hydroxy
silicone oil 2 ~ 3. Hot air vulcanized extruded product high tear
resistant silicone rubber formula: methyl vinyl silicone rubber 100;
fumed silica W909 50; paste DCBP (40%) 1.5.