Appeal 2007-1366
Application 90/005,090
1 permeability of this composition was said to be 6.3 x 10-10. The contact lens
2 material of Example 42 is a copolymer made from 50 grams of S3, 43 grams
3 of MMA and 7 grams of conventional cross-linking agent ethylene glycol
4 dimethacrylate (EDMA).6 The oxygen permeablility of the Example 42
5 copolymers is said to be 9.6 x 10-10. Based upon the difference in oxygen
6 permeability, Patentee asserts that the substitution of a polyfunctional
7 siloxanyl ester cross-linking agent, the conventional EDMA would be
8 expected to decrease oxygen permeability. However, it appears that the
9 increased oxygen permability of the Example 42 copolymer may result from
10 the 10 gram increase in the amount of S3 organosiloxane comonomer. As
11 noted by Tanaka, “[t]he oxygen permeability of the copolymers of the
12 present invention is in proportion to the content of the before-mentioned
13 particular organosiloxane . . . .” Tanaka, 11:23-25. See also Tables 3, 4 and
14 8 which demonstrate the significant increase in oxygen permeability in
15 proportion to an increase in organosiloxane comonomer. While we can not
16 draw any conclusion from a comparison of Examples 29 and 42, we note
17 that Tanaka credits at least a portion of the oxygen permeability of the
18 copolymer to the siloxane bonds in the multifunctional siloxanyl ester
19 crosslinking agent. Tanaka, 8:35-39 (“Since these cross-linking agents . . .
20 have siloxane bonds in their molecules, the oxygen permeability of the
21 obtained cross-linked copolymers is high . . . .”). A person of ordinary skill,
22 upon reading Tanaka, would neither be discouraged from following the path
23 set out in the reference, nor be led in a direction divergent from the path that
24 was taken by Patentee. Gurley , 27 F.3d at 553, 31 USPQ2d at 1131, Syntex,
6 The compound ethylene glycol dimethacrylate may also be called
ethylenedimethacrylate.
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