Patent ID: 11872327
Assignee: TORAY INDUSTRIES, INC.
Field: Medical technology (Instruments)
Classification: CPC A  G  C | IPC A  C  G

Claim 3:
4. The medical device according to claim 1, wherein the silicone hydrogel has a zero-stress period of 0.1 second to 2 seconds in hydrous state,
wherein the zero-stress period means a length of time during tensile stress measurement in which an operation of
drawing a test piece having a width of 5 mm and a thickness within the range of 0.05 mm to 0.2 mm held at an inter-supporting-point distance of 5 mm, using a load cell with a maximum load of 2 kg at a rate of 100 mm/minute, until the inter-supporting-point distance becomes 10 mm, and then
reducing the inter-supporting-point distance to 5 mm at the same rate,

is repeated three times while obtaining measured values at 20-millisecond intervals,
the length of time being a length of time
from the time point when the stress becomes zero during the second reduction of the inter-supporting-point distance to 5 mm
to the time point when the stress becomes non-zero after starting the third drawing, wherein zero stress means a state with a measured value within the range of −0.05 gf to 0.05 gf.