1. A medical rubber closure comprising a disc-shaped flange portion and a leg portion formed to be continuous to a lower surface side of the flange portion and wherein a region at the lower surface side of the flange portion and the leg portion are made of a nitrile based rubber, a region at a top surface side of the flange portion is made of a butyl based rubber, and the leg portion is laminated with a coating layer made of a fluorine based resin film.
2. The medical rubber closure according to claim 1, wherein the nitrile based rubber is at least one type of rubber selected from the group consisting of acrylonitrile butadiene rubbers, hydrogenated acrylonitrile butadiene rubbers, carboxylated acrylonitrile butadiene rubbers, and acrylonitrile butadiene isoprene rubbers.
3. The medical rubber closure according to claim 1, wherein the butyl based rubber is at least one type of rubber selected from the group consisting of butyl rubbers, brominated butyl rubbers, chlorinated butyl rubbers, and brominated isobutylene-p-methylstyrene copolymer rubbers.
4. A method for manufacturing medical rubber closure by which the medical rubber closure according to claim 1 is manufactured through
a step of vulcanization molding a sheet of unvulcanized nitrile based rubber that is to form the leg portion and a fluorine based resin film that is to form the coating layer to form a primary molded article, including the leg portion made of the nitrile based rubber and the coating layer made of the fluorine based resin film and being laminated to the leg portion by vulcanization bonding, and thereafter punching out the leg portion individually to prepare a closure blank, and
a step of setting the closure blank in a secondary molding mold, overlapping thereon a sheet of unvulcanized nitrile based rubber that is to form the region at the lower surface side of the flange portion and a sheet of unvulcanized butyl based rubber that is to form the region at the top surface side of the flange portion, and performing vulcanization molding in this state to form the region at the lower surface side of the flange portion made of the nitrile based rubber and the region at the top surface side of the flange portion made of the butyl based rubber and vulcanization bonding the two regions and the closure blank to each other.
5. The method for manufacturing medical rubber closure according to claim 4, wherein a sheet of unvulcanized nitrile based rubber that is to form the region at the lower surface side of the flange portion and a sheet of unvulcanized butyl based rubber that is to form the region at the top surface side of the flange portion are vulcanization-molded together with the closure blank in a state of being overlapped via a sheet of ultrahigh molecular weight polyethylene.
6. The method for manufacturing medical rubber closure according to claim 5, wherein the sheet of ultrahigh molecular weight polyethylene has a thickness of not less than 25 \u03bcm and not more than 200 \u03bcm.
7. The method for manufacturing medical rubber closure according to claim 4, wherein as the sheets of nitrile based rubber and the sheet of butyl based rubber, those of two colors of extremely high color difference such that the color difference value dE* with respect to each other as expressed in NBS units is 6.0 to 12.0 or those of two colors of different color systems such that the color difference value dE* is 12.0 or higher are combined and used.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A radial tire for airplane comprising a pair of bead cores, a radial carcass comprised of at least one carcass ply toroidally extending between the pair of bead cores, and a belt disposed on an outer periphery of a crown portion of the radial carcass and comprised of plural belt layers each containing organic fiber cords, in which a total strength in a circumferential direction over a full width of the belt Tbelt(N) satisfies TbeltWD\u22671.5\xd7106 when an outer diameter of the tire is D (m) and a width of the tire is W (m), and at least one layer of the belt layers is constituted with an organic fiber cord spirally winding at an angle of approximately 0\xb0 with respect to an equatorial plane of the tire and satisfying the following equations (I) and (II):
\u03c3\u2267\u22120.01E+1.2 \u2003\u2003(I)
\u03c3\u22670.02 \u2003\u2003(II)
(wherein \u03c3 is a heat shrinkage stress at 177\xb0 C. (cNdtex) and E is an elastic modulus at 25\xb0 C. under a load of 49 N (cNdtex)).
2. A radial tire for airplane according to claim 1, wherein a total strength KO of the belt layer in the circumferential direction per unit width at the equatorial plane PO of the tire and a total strength K2 of the belt in the circumferential direction per unit width at a position P2 corresponding to \u2154 of a maximum width W of the belt layer centering on the equatorial plane satisfy a relation of 0.2\u2266K2KO\u22660.8.
3. A radial tire for airplane according to claim 1, wherein the organic fiber cord satisfying the equations (I) and (II) is a polyketone fiber cord.
4. A radial tire for airplane according to claim 3, wherein the polyketone fiber cord satisfying the equations (I) and (II) is a polyketone fiber cord substantially having a repeated unit represented by the following formula (III):
(wherein A is a moiety derived from an unsaturated compound polymerized through unsaturated bonds, and may be same or different in repeated units).
5. A radial tire for airplane according to claim 4, wherein A in the formula (III) is ethylene.