The present application relates to a kind of high
ductility silicon hydrogel, which is prepared by
polymerization reaction of polymerizable composition containing
thiol with functionality greater than or equal to 3, and the elongation of the high
ductility silicon hydrogel is 285%-439%.The present application also relates to a kind of high
ductility contact lens and its preparation method.By adding
thiol with functionality greater than or equal to 3 as crosslinking agent in the formula of
silicon hydrogel, the formed silicon hydrogel
polymer network is more regular, more full and more stretchy, so that the prepared
contact lens has good ductility, and the
contact lens has
high water content and
low modulus.In addition, compared with the contact lens formed without adding
thiol with functionality greater than or equal to 3, the
size change of the contact lens formed after adding thiol with functionality greater than or equal to 3 is less than 5%.