PAB Applies AZT finds that inventor could not soundly predict utility throughout entire claimed range

PAB Applies AZT finds that inventor could not soundly predict utility throughout entire claimed range

Re: Patent Application No. 2,248,228  [CD


The Commissioner of Patents reviewed the decision of the PAB
relating to patent application 2,248,228 entitled ‘METHOD OF PRODUCING
under s.2 of the Patent Act for lack
of demonstrated utility or sound prediction of utility.

The present invention focuses on developing an n-pentane
or i-pentane blown rigid foam that avoids the disadvantages associated with the
use of cyclopentane or conventional i or n-pentane foams.

The application was filed on March 3, 1997 and claims
priority based on a German patent filed March 15, 1996.

The application was rejected by the Examiner in a Final
Action dated February 1, 2011. It was rejected based upon defects identified
with respect to utility and sufficiency. Both defects relate to claimed ranges
of surface tension values of i and n-pentane as a blowing agent.

There are 11 claims with claim 1 being the only
independent claim. Claim 1 states:

1. A process for preparing polyurethane rigid foams from polyols and
polyisocyanates as well as blowing agents and optionally foam auxiliary agents,
characterised in that the polyurethane rigid foam is obtained by reacting

A) a polyol component comprising at least 3 isocyanate-reactive
hydrogens and containing 1. 60 to 100% of polyethers and/or polyesters with a
molecular weight of 250 to 1,500 and at least 2 hydroxyl groups, which have a
surface tension of 6 to 14 mN/m with respect to i-pentane and/or n-pentane as
blowing agent, wherein the polyethers are obtained by the polyaddition of 70 to
 100 wt.% of ethylene oxide and 0 to 30
wt. % of propylene oxide to starter compounds, 2. I-pentane and/or n-pentane as
blowing agent, 3. water and 4. optionally auxiliary agents and additives with B)
a polyisocyanate with an NCO-content of 20 to 48 wt. % which has a surface
tension of 4.0 to 8 mN/m with respect to i-pentane or n-pentane as blowing


Utility is demonstrated or soundly predicted as of the
filing date. Utility is assessed against the promise of the invention. The PAB
notes that construing an object clause as a promise on its own should not be
done. The utility is therefore what was stated by the Applicant in the response
to the Final Action – overcoming the disadvantages of the prior art foams
employing n and i-pentane as a blowing agent to produce a rigid foam with low
thermal conductivity.

The next issue the PAB raises is whether the promised
utility is demonstrated over a range of surface tensions. The Applicants
response to the last office action indicates that they feel utility has been
demonstrated across a range of foams. The PAB notes that two data points were

The issue for the PAB was whether sufficient data was
provided. Where a range is claimed with limited data the full extent must be
soundly predicted. The PAB relied on AZT for their sound prediction analysis. The
PAB noted that there were very specific surface tension requirements in order
for the promised invention to work. The PAB also noted that the Applicants
stated sound line of reasoning does not appear in the patent specification. The
PAB concludes:

A person skilled in the art would not be able to predict the full scope
of the claimed surface tension ranges.


The Commissioner upheld the PAB findings and refused to
grant the patent on the basis of being non-compliant with section 2 of the Patent Act.


In the present case we are now seeing the “promise
doctrine” being applied by the Patent Office itself, rather than waiting for
its application by the Courts during litigation.