US 12,006,391 B2
Medical rubber composition, medical rubber part, and pre-fillable syringe
Hirofumi Konishi, Kobe (JP); Toshikazu Kondo, Kobe (JP); Masayoshi Kashibe, Kobe (JP); and Hideyuki Shigemoto, Kobe (JP)
Assigned to SUMITOMO RUBBER INDUSTRIES, LTD., Kobe (JP)
Filed by Sumitomo Rubber Industries, Ltd., Kobe (JP)
Filed on Jul. 8, 2022, as Appl. No. 17/860,124.
Claims priority of application No. 2021-113756 (JP), filed on Jul. 8, 2021.
Prior Publication US 2023/0008859 A1, Jan. 12, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. C08F 36/06 (2006.01); A61M 5/32 (2006.01); C08F 210/10 (2006.01); C08F 236/08 (2006.01); C08K 3/36 (2006.01); C08K 5/14 (2006.01); C08K 5/3492 (2006.01)
CPC C08F 36/06 (2013.01) [A61M 5/3202 (2013.01); C08F 210/10 (2013.01); C08F 236/08 (2013.01); C08K 3/36 (2013.01); C08K 5/14 (2013.01); C08K 5/3492 (2013.01); C08K 2201/006 (2013.01); C08K 2201/019 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A medical rubber composition comprising:
(a) an isobutylene-isoprene rubber;
(b) a diene-based rubber; and
a silica having a BET specific surface area not lower than 130 m2/g, wherein
an amount of (a) the isobutylene-isoprene rubber contained in 100 parts by mass of a rubber component composed of (a) the isobutylene-isoprene rubber and (b) the diene-based rubber is larger than 30 parts by mass and smaller than 55 parts by mass,
an amount of the silica contained per 100 parts by mass of the rubber component is 3 parts by mass to 9 parts by mass, and
an O2 permeability coefficient of a test slab of the medical rubber composition is at least 2.0×10−9 cc·cm/cm2·sec·cmHg and a concentration of potassium permanganate reducing substance in an oozing-substance test of a test sample of the medical rubber composition is lower than 0.5 mL/100 mL,
wherein the test slab is prepared by press-molding the medical rubber composition at 180° C. for 6 minutes and has a thicknesses of 0.5 mm to 1.0 mm, and the test sample is prepared by press-molding the medical rubber composition at 180° C. for 6 minutes and having a diameter of 17 mm and a thickness of 2 mm.