Usual term
(1) The general rule is that a patent of addition remains in force for so long as the patent for the main invention remains in force. However, this rule is subject to the exceptions set out in subsections (3) and (4).
(2) The term of a patent of addition may be extended under Part 3 of Chapter 6, even though the patent for the main invention is not extended under that Part.
Patent of addition extended
(3) If the term of a patent of addition is extended under Part 3 of Chapter 6:
(a) the extension begins at the end of the unextended term of the patent for the main invention; and
(b) when the extension begins, the patent of addition becomes an independent patent.
Patent for main invention extended
(4) If:
(a) the term of the patent for the main invention is extended under Part 3 of Chapter 6; and
(b) the term of the patent of addition is not extended under that Part;
the term of the patent of addition expires at the end of the unextended term of the patent for the main invention.