Found this earlier in an alley, it looks like it used to have a green color I could see when washing it. Might've said protect americans and canadians? Or protecting... I can't find anything on it.
Just a guess but I think the text might have read “Protected by Canadian Patent No. 1968XX”. Unfortunately the last 2 or 3 digits are missing which would ID what it was from.
My first thought was that it's part of the inside of an old iron cook stove.
We had a lot of stove manufactures here in the east over the years and they were often in competition with US patents.
Unfortunately, your find is missing most of the patent information that you need to complete your research.