Appeal No. 96-3717
Application 08/229,115
The claims on appeal require that the polyurethane composition exhibit a water absorption at body
temperature of 5 wt% or less. Solomon discloses that the water absorption for polyurethane 80 A and
polyurethane 55 D are 1.85% and 1.66% , respectively (col. 4, lines 31-34). This water absorption is
clearly within the water absorption defined by appellants’ claims. Appellants’ claims also require the
claimed medical tube as having certain modulus of transverse elasticity properties and a mechanical loss
tangent of at least 0.5, both of which are a function of body temperature. The examiner asserts that the
transverse elasticity and mechanical loss of tangent properties are inherent in the polyurethanes disclosed
by Solomon. Appellants argue that the properties are not inherent and that Solomon does not teach or
suggest the claimed molar amounts of isocyanate, chain extender or polyol components of the polyurethane.
It is well settled that when a claimed product appears to be substantially identical to a product
disclosed by the prior art, the burden is on the applicant to prove that the product of the prior art does not
necessarily or inherently possess characteristics or properties attributed to the claimed product. In re
Spada, 911 F.2d 705, 708-09, 15 USPQ2d 1655, 1657-58 (Fed. Cir. 1990). The reason for this is that
the Patent and Trademark Office is not able to manufacture and compare products. In re Best, 562 F.2d
1252, 1255-56, 195 USPQ 430, 433-34 (CCPA 1977). Under such circumstances, a rejection may be
properly made under 35 U.S.C. § 102 or § 103. In re Best, supra.
According to appellants’ specification, the mechanical loss tangent and modulus of transverse
elasticity are linked to a feeling of physical disorder experienced by patients, which disorder appellants want
to avoid with their polyurethane composition. Appellants state on pages 5 and 6 of the specification that
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