Appeal 2007-1366
Application 90/005,090
1 described by Tanaka. Tanaka teaches that the cross-linkers are a substitute
2 for “known cross-linking agents generally employed in the polymerization
3 of a vinyl monomer . . . .” Tanaka, 7:62-8:14. The cross-linking agents are
4 taught to be preferred because they provide contact lens materials having
5 good oxygen permability because of their siloxane bonds. Tanaka, 8:35-39.
6 Lastly, the polyfunctional siloxanyl ester cross-linking agents are said to
7 provide hydrophilic groups which are beneficial for the hydrophilic property
8 of contact lens materials. Tanaka, 8:39-46.
9 We fail to see why the fact that Gaylord’s comonomers do not include
10 an internal glycerol group would teach away from the use of the cross-
11 linking agents taught by Tanaka. The person having ordinary skill in the art
12 understands that the mechanism of cross-linking relies on the presence of the
13 terminal unsaturated carbon bonds. The person having ordinary skill in the
14 art would have expected that Tanaka’s preferred polyfunctional siloxanyl
15 ester cross-linking agents, which also include terminal unsaturated carbons
16 (=CH2), would also be effective cross-linking agents with Gaylord’s
17 comonomers. We have not been directed to evidence in the record which
18 shows the contrary.
19 With respect to the comparison of the oxygen permeability of
20 Examples 29 and 42, we can not draw any conclusion from these examples.
21 The two examples are not comparable because of the different amounts of
22 organosiloxane comonomer. The contact lens material of Example 29 is a
23 copolymer said to have been made from 40 grams of an organosiloxane
24 comomoner designated S3, 50 grams of methylmethacrylate (MMA) and 10
25 grams of a polyfunctional siloxanyl ester cross-linking agent, TMSBPGMA
26 (tetramethyldisiloxanylbis (propylglycerol methacrylate)). The oxygen
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