Appeal 2007-1366
Application 90/005,090
1 agents, have terminal unsaturated carbons. 5 It would have been expected,
2 and therefore obvious, to replace the conventional cross-linking agents
3 described by Gaylord with the multifunctional siloxyanyl ester cross-linking
4 agents preferred by Tanaka.
5 Patentee argues that Tanaka teaches away from using Tanaka’s
6 polyfunctional siloxanyl ester cross-linking agents with comonomers of the
7 type used by Gaylord. Patentee argues that Gaylord’s ester monomers do
8 not have an internal glycerol group for increased hydrophilicity which
9 monomers are taught by Tanaka as having undesirable water-repelling
10 properties when used in contact lens material. Patentee also relies on two of
11 Tanka’s 53 examples, Examples 29 and 42, as indicating that Tanaka’s
12 polyfunctional siloxanyl ester cross-linking agents actually decrease oxygen
13 permeability.
14 Tanaka does not teach away.
15 Tanaka provides ample reasons for using polyfunctional siloxanyl
16 ester cross-linking agents with comonomers other than those specifically
5 Ethylene glycol dimethacralate, described as crosslinkers by both Gaylord
and Tanaka, may be represented by the following formula:
CH3 CH3
│ │
CH2=C-C-O-(CH2)2-O-C-C=CH2
║ ║
O O
Tanaka’s preferred cross-linkers similarly have terminal unsaturated carbons
(=CH2). For example. Tanaka’s preferred siloxanyl alkyl esters include
those represented by general formula:
R1 CH3 CH3 R2
│ │ │ │
CH2=C─C─O─(CH2)n─Si─(O─Si)m-(CH2)n─O─C─C=CH2
║ │ │ ║
O CH3 CH3 O
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