IIT Madras’s application number 4032/CHE/2013 was refused by the Controller of Patents on grounds of non-patentability under section 3(a) and section 3(d) of the Patents Act, lack of industrial applicability and lack of inventive step. IIT Madras preferred an appeal against said refusal before the Madras High Court which recently adjudicated on the merits of the refusal (IIT Madras vs The Controller of Patents and Designs & Ors. (T) CMA (PT) No.92 of 2023).

The refused application claimed a method of doping potassium in ammonium percholate by recrystallization process, without using any reagents, the said method comprising,

1. Completely dissolving the ammonium perchlorate in distilled water
2. Filtering the solution from step (a) to remove floating impurities
3. Heating the filtrate from step (b) to remove the water and
4. Placing the ammonium perchlorate thus obtained from step (c) in a hot air oven at 333 K for two days to completely remove moisture

wherein, the ammonium perchlorate acquires potassium from the filtering material during filtering process and the amount of potassium being doped in ammonium perchlorate depends on the type of filtering material and time of exposure of the solution to the filtering material.

For the refusal under section 3(d) of the Patents Act and for lack of inventive step, the Controller had relied on a prior art document D1, namely, US 3,269,879, example 3 of which described a method involving

• dissolving ammonium perchlorate in water,
• pouring the solution into a 3-neck flask provided with a stirrer, thermometer and a dropping funnel,
• adding an aqueous solution of potassium iodate to the aqueous ammonium perchlorate solution,
• concentrating the vigorously stirred mixture at 50° C under reduced pressure, and
• upon obtaining a thick slurry, filtering, drying and screening the precipitate to obtain an isomorphous co-crystallized product.

The Appellant asserted that their invention was different from and not obvious in view of D1 as their invention did not require any external material to dope potassium in ammonium perchlorate and used the filtrate material as the source of potassium instead. The Appellant also submitted that this use of filtrate material as the potassium source led to significant cost reduction.   

The insights provided by Madras High Court into the patentability of this invention are as follows.

Section 3(a) of the Patents Act

Section 3(a) of the Patents Act prohibits the grant of a patent to inventions which are frivolous or which claim anything obviously contrary to well established natural laws. In the impugned order, the Controller had refused the application for being frivolous and it was alleged that the applicant had merely used a new source of potassium. Notably, the Controller had not raised the objection under Section 3(a) either in the first examination report (FER) or in the hearing notice.

Based on the absence of the objection under section 3(a) of the Patents Act in the FER and the hearing notice, the Court held that the subject application’s refusal under Section 3(a) contravened Section 14 read with Section 80 of the Patents Act and the principles of natural justice as the Appellant was deprived of an opportunity of being heard on said ground.

Section 3(d) of the Patents Act

While addressing findings in relation to Section 3(d) in the impugned order, the Court underlined the three exclusions prescribed under the provision viz:

(a) the mere discovery of a new form of a known substance unless there is enhancement in the known efficacy of the substance;

(b) mere discovery of any new property/new use for a known substance; or

(c) mere use of a known process, machine or apparatus unless it results in a new product or employs a new reactant.

The Court remarked that only the exclusion (c) is relevant to process claims and noted that for a compound to be considered as a reactant, it must trigger or cause a chemical reaction to form a new compound. The Court found that the claimed invention was rightly excluded from patentability under Section 3(d) as no new reactant was used in the claimed process which adopted known processes such as those disclosed in D1 and such adoption also did not result in a new product.

Industrial Capability

While evaluating industrial capability of the claimed invention, the Court referred to the 2002 amendment of the Patents Act that replaced the term ‘useful’ with ‘capable of industrial application’ in Section 2(1)(j). Noting that an equivalent phrase ‘susceptible of industrial application’ was used in the European Patent Convention and in the UK Patents Act, 1977, the Court referred to the UK Supreme Court judgment in Human Genome Inc. v Eli Lily and Company [2012] RPC 6 and opined that for a claimed invention to be capable of industrial application it “must disclose a practical application and should be capable of being exploited for commercial benefit without significant difficulty. The possibility of doing so must be discernible from its specification and common general knowledge”.

The Controller had justified the refusal of the application for lack of industrial applicability based on the reasoning that the use of filtering material as a potassium source would require replacing the filtering material with new ones to achieve the desired potassium content, which may make the invention more expensive than when adding potassium from an external source.

Disagreeing with the Controller, the Court highlighted that the industrial applicability limb of Section 2(1)(j) only requires the invention to be capable of being put to practical use and does not require the claimed invention to be capable of industrial use at a lower cost compared to prior art(s). Put differently, while a comparatively lower cost could demonstrate economic significance under Section 2(1)(ja), it has no relevance in ascertaining industrial applicability. The Court also noted that for justifying the refusal on the ground of lack of industrial applicability, the Controller had not contended that the increase in combustion obtained due to doping of ammonium perchlorate with potassium did not have industrial application. Rather, the focus of the Controller’s reasoning was on cost. Finding practical merit in the invention claimed, the Court held that the subject invention qualified the test of being capable of industrial application and the objection under Section 2(1)(j) was found untenable.

Inventive Step

Lastly, while examining the inventive step in the claimed invention, the Court pointed that to be inventive:

• the claimed invention must exhibit technical advancement as compared to the existing knowledge or have economic significance or both; and
• the purported technical advance must not be obvious to a person skilled in the art.

The Court clarified that the notional person skilled in the art is a person with above average skills and normal imagination, who lacks ingenuity or inventiveness.

The Court held that the claimed technical advance of choosing the type of filtering material out of the known filtering materials would be obvious to a person skilled in the art based on the disclosure of D1 and common general knowledge. The Court also noted that without any comparative data demonstrating that the costs of using filtrate material, which requires frequent changing, vis-à-vis using an external reagent as a potassium source, the economic significance of the claimed invention cannot be established. Holding that the Appellant’s intervention in the method which was limited to choosing the appropriate filtration material and defining the time of exposure of ammonium perchlorate to the filtering material to reach the ideal potassium weight percentage, was only routine experimentation and did not require inventive ingenuity, the Court upheld the Controller’s refusal of the application for lack of inventive step.

In conclusion, the Court dismissed the appeal and affirmed the rejection of the subject application.