Announcement on Trial Decision Rejecting Second Request for Invalidation of Tateho Patent (Invalidation 2018-800072) (Maintenance of Patent)

May 31, 2019
Yasunori Kitano, Representative Director and President
Tateho Co., Ltd.

To whom it may concern：

On April 19, 2019, in the second patent invalidation trial brought by Kyowa Chemical Industry Co., Ltd. (“Kyowa Chemical”) against Tateho Co., Ltd. (“Tateho”) to invalidate Tateho’s Patent No. 3761867 (the “Tateho Patent”) (a trial requesting invalidation of the Tateho Patent; the “Trial”), the Japan Patent Office accepted Tateho’s claim and rendered a decision that the Tateho Patent should be maintained and that the Kyowa Chemical’s request would not be accepted (the trial decision rejecting the request).

The Trial is a second patent invalidation trial brought on June 6, 2018, by Kyowa Chemical, to invalidate the Tateho Patent. As already announced (published on our website on October 19, 2018), in the first patent invalidation trial brought by Kyowa Chemical, on August 30, 2018, the Japan Patent Office rendered a decision that the Tateho Patent should be maintained.
In the present Trial, the Japan Patent Office again accepted Tateho’s claim and rendered a decision that the Kyowa Chemical’s request would not be accepted. Tateho recognizes that the decision made by the Japan Patent Office is sensible.

The Tateho Patent relates to light burned magnesium oxide used as annealing separation agent when manufacturing electromagnetic steel sheets that are used for transformers, etc.
Its characteristic is that it enables the creation of excellent forsterite film on electromagnetic steel sheets by maintaining the quantities of calcium, phosphorus, boron, silicon and sulfur contained in the light burned magnesium oxide within specific ranges.

As well as the Tateho Patent, Tateho will protect inventions relating to the light burned magnesium oxide used as annealing separation agent as patents and promote the effective use of the patent rights through license and other measures, thereby actively contributing to the development of the industry related to electromagnetic steel sheets.

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