Patenting Alloys at the EPO: Novelty

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Patenting Alloys at the EPO Novelty
30th March 2022 By Michael Ford, Senior Associate
The European Patent Office has developed a
consistent approach to the examination of patent
applications relating to alloys, taking into
consideration the unique nature of these
important industrial materials. Our first
article on patenting alloys at the EPO focused on
clarity. In this article, we consider the EPOs
practice as regards novelty.
Novelty
The EPOs approach to the assessment of novelty
is strict all of the features of a claim must
be directly and unambiguously disclosed in the
prior art for the claim to lack novelty. The
meaning of directly and unambiguously disclosed,
however, can depend to some extent on the
technical context of the documents in question.
When assessing the novelty of alloy claims,
there are some particular considerations to bear
in mind.
Compositional overlap

• An alloy claim will typically define a chemical
  composition in terms of the amounts of each
  element present in the alloy, as in the following
  simplified example.
• 1. Alloy comprising from 5 wt. to 10 wt. A
  and from 3 wt. to 7 wt. B, the balance being
  C and the usual impurities.
• For a prior art document to destroy the novelty
  of this claim, it must disclose an alloy having
  a composition falling within these ranges.
• Prior art documents, particularly patent
  documents, will typically disclose alloy
  compositions in two different ways
• precise compositions of specific example alloys
  provided as evidence that the claimed invention
  can be put into practice and achieves the desired
  technical effect and

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• general ranges defined by lower and upper
  endpoints given for each element.
• Specific examples
• The assessment of novelty is relatively
  straightforward when considering only
  disclosures of the specific examples. If one of
  the examples has a composition falling entirely
  within the claimed ranges, the claim lacks
  novelty. For example, claim 1 above would lack
  novelty over a prior art example alloy consisting
  of 7 wt. A and 3.5 wt. B, the balance being
  C.
• However, claim 1 would not lack novelty if the
  composition of the prior art example were to
  differ in terms of the amount of any of A, B or
  C, or if the composition were to include any
  further elements beyond impurity levels (because
  claimed alloy compositions are considered to be
  closed, as discussed in our article on clarity).
• For example, claim 1 would be novel over an
  example alloy consisting of 7 wt. A and 2 wt.
  B, the balance being C. It would also be novel
  over an example alloy consisting of 7 wt. A, 3.5
  wt. B and 1 wt. D, the balance being C.
• Ranges
• The situation, however, becomes more complicated
  when the prior art disclosure is defined in
  terms of ranges for each element present.
• If each of the ranges disclosed in the prior art
  falls within the corresponding claimed ranges,
  the claim lacks novelty. This is illustrated
  figuratively below.

However, what happens if one or more of the prior
art ranges are broader than, or only partially
overlap with, the corresponding claimed ranges,
as shown below?
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• In such cases, the EPO applies the rules relating
  to selection inventions set out in the
  Guidelines for Examination (Part G, VI-8).
  According to these rules, a sub-range selected
  from a broader range in the prior art is
  considered to be novel if
• the selected sub-range is narrow compared to the
  known range and
• the selected sub-range is sufficiently far
  removed from any specific examples in the prior
  art and from the end-points of the known range.
• Of course, where one range partially overlaps
  another, the claimed range cannot be considered
  to be far removed from the end-points of the
  known range by definition, one of the
  end-points of the known range will fall within
  the overlapping claimed range. Therefore, if
  there is only partial overlap in the ranges of
  one of the elements in the composition, and
  there are no other differences between the
  claimed alloy and the prior art disclosure, an
  EPO examiner can object that the disclosed
  end-point in the prior art is an explicitly
  disclosed value falling within the claimed range
  and therefore takes away the novelty of the
  claim.
• However, the case law also requires examiners to
  take into account whether the skilled person
  would seriously contemplate applying the
  technical teaching of the prior art in any area
  of overlap. In Board of Appeal decision T
  0261/15, for example, which concerned a patent
  for a pearlitic steel rail defined by a
  composition which overlapped with the prior art
  in terms of multiple components, it was decided
  that the limit values of a known range, although
  explicitly disclosed, should not be treated in
  the same way as the examples when assessing
  novelty. While the examples are disclosures of
  compositions which the skilled person would
  seriously contemplate implementing, the skilled
  person would not necessarily seriously
  contemplate working in the region of the
  end-points of general ranges.
• In the particular context of alloys, the skilled
  person also knows that different alloying
  elements can interact with one another in an
  unpredictable way to produce precipitates and
  solid solutions, and so the skilled person does
  not make arbitrary compositional changes.
  Therefore, following T 0261/15, concentration
  ranges disclosed in the prior art should not be
  considered in isolation but must instead be
  viewed in combination. In addition, where there
  is overlap in terms of the amounts of more than
  one element in an alloy, the total conceptual
  area of overlap between the claims and the prior
  art is likely to be narrow.
• Another relevant Board of Appeal decision (T
  1571/15) concerned a patent for a nickel- based
  superalloy defined in terms of a chemical
  composition which overlapped with the broadest
  ranges of multiple components in a prior art
  document. Indeed, the patent claim even covered
  the centre of the broadest range for titanium
  disclosed in the prior art. However, the prior
  art also disclosed preferred compositional ranges
  which did not

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overlap with the claim, as well as an exemplary
composition which fell entirely within the
preferred ranges. The Board therefore considered
there to be a pointer in the prior art to work
within the preferred ranges and not to work
within the broader ranges overlapping with the
claim under consideration, such that the skilled
person would not seriously contemplate working
in the area of overlap (despite the claim
covering the centre of the broadest
range). Accordingly, as long as none of the
specific examples in the prior art fall within
the area of overlap, it is often possible to
overcome novelty objections based on overlapping
ranges.
Implicit disclosure
In addition to the elemental composition, claims
to an alloy often recite microstructural
features or define physical or chemical
properties of the alloy in terms of parameters.
Such microstructural or parametric features may
not be disclosed explicitly in the prior art or
may not be directly comparable with the prior art
disclosure. For example, a claim may define a
microstructure in terms of a particular size of
precipitate which is simply not mentioned in the
prior art. Alternatively, a claim could recite
the impact resistance of an alloy component as
measured by Charpy impact testing at a particular
temperature, whereas the prior art may disclose
an Izod impact strength test at a different
temperature. In such situations, it can be
difficult to assess whether the claimed alloy is
anticipated by the prior art, particularly where
the elemental composition of the alloy is not
itself new. In such cases, an EPO examiner will
often object that the claim to the alloy lacks
novelty on the basis that the claimed feature or
parameter would inevitably result in the prior
art from application of the same manufacturing
method to an alloy having the same chemical
composition. That is to say, the prior art will
be taken to disclose the claimed alloy
implicitly or inherently. When faced with such
an objection, it can be tempting to amend the
alloy claim to add further compositional or
microstructural limitations which provide a
clearer distinction over the prior art. However,
in some cases, it is possible to overcome this
type of objection by explaining why the
manufacturing method of the claimed invention is
different from that disclosed in the prior art.
For example, if it can be shown that the claimed
precipitate or impact resistance is only achieved
when the alloy is heated under certain annealing
conditions, and the annealing conditions
disclosed in the prior art are different, then
it is arguable that the precipitates or impact
resistance are not implicitly disclosed in the
prior art document.
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When drafting alloy applications, we therefore
recommend including explanations of the purpose
of any manufacturing steps and the particular
conditions used, and tying these back to the
alloy microstructure and the desired properties.
Comparative examples which evidence the effect
of varying manufacturing conditions are also
particularly helpful.
Further advice Michael Ford is a Senior Associate
in our Materials Group with extensive experience
of protecting alloy inventions in Europe. If you
would like further advice on this topic, please
get in touch.