TOPICS

“Ground Consolidation Material and Ground Improvement Method”

Overview:

This case involves a request to overturn a decision to invalidate a patent. The court overturned the decision to invalidate the patent.

▶ Link to a summary and full text of the trial decision (Japanese)

Main Issue:

Whether or not the difference between Corrected Invention 1 and the Cited Inventions involved ease of conception.

Court’s Ruling:

The ground consolidation material used in the ground improvement methods of Corrected Invention 1 and the Cited Inventions involves slurry (suspension grout) that contains liquid glass and fine particulate slag as effective ingredients, and the principle of consolidation is the hydraulic property of slag whereby “an integrated consolidate is formed by an alkali fraction in a low-molar ratio silica solution solidifying due to inducing a latent hydraulic property in a fine particulate slag and a silica fraction in the low-molar ratio silica solution turning into a gel in reaction with a calcium fraction in the fine particulate slag, such that a silica gel interconnects consolidating portions due to slag in soil”. On the other hand, the ground consolidation materials taught in the documents of Plaintiff’s Exhibits 5, 6 and 9 involve…, and the principle of consolidation is ground pH whereby the infusion liquid “permeates between soil particles, and the pH of portions in contact with the soil transitions in the neutral direction and gelation proceeds” (Plaintiff’s Exhibit 5), and thereby “the infused acidic chemical starts to consolidate as it becomes more-or-less neutral in reaction with the alkali fraction in the soil” (Plaintiff’s Exhibit 6), and so the ground consolidation materials of Corrected Invention 1 and the Cited Inventions differ in terms of the principle of consolidation.

Furthermore, concerning the conditions for infusion of the ground improvement method, the documents of Plaintiff’s Exhibits 5, 6 and 9 explain the magma action method…. However, this magma action method is mentioned strictly in relation to the conditions for infusion when an acidic chemical solidifies in reaction with an alkali fraction in soil, and it cannot be said that these would naturally be suitable as conditions for infusion of the ground consolidation materials of Corrected Invention 1 and the Cited Inventions that solidify due to hydraulic property of slag in the chemical. This is because, in addition to the difference in the principles of consolidation, it cannot be immediately said that, just because they are the same technical field of ground improvement, it is possible to realize the technical problem of forming high strength consolidate with a large diameter under the same infusion conditions. No descriptions or the like that would suggest that the magma action method could be applied to a suspension grout, which differs in terms of the principle of consolidation, are also apparent in the documents of Plaintiff’s Exhibits 5, 6 and 9, and thus it should be stated that one of ordinary skill in the art could not have easily conceived of the infusion conditions corresponding to the special properties of the suspension grouts of Correct Invention 1 and the Cited Inventions (primary gelation, pseudoplasticity and secondary gelation) based on the Cited Inventions and the documents of Plaintiff’s Exhibits 5, 6 and 9.

Comments:

The defendant (JPO) asserted that “the decision was made that one would arrive at the features of Corrected Invention 1 if the ground consolidation material were infused into the ground according to the Cited Inventions over a period equal to or greater than the soil gelation time (GTso), on the grounds that it the ‘gelation time’ of the technical matters of the documents of Plaintiff’s Exhibits 5, 6 and 9 are conceivably equivalent to the ‘time until primary gelation’ of Corrected Invention 1, or a time corresponding to a state in which even further solidification had proceeded”, but the court did not accept the defendant’s assertion as no such assertion was admissible.

Kazuyuki YOSHIZUMI