Method for precipitating an organic resin from an alkaline solution thereof
CA 2081135 C · Owner: Krulik, Gerald A. · Inventors: Krulik, Gerald A.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The use of aluminum sulfate to neutralize alkaline solutions yields a gelatinous precipitate. When neutralization of the solution causes other materials to precipitate along with the gel, filtration of the precipitated materials is very difficult because of the gel. The addition of water soluble magnesium, aluminum, and/or calcium salts as primary neutralizing agents for an alkaline stripper solution of a photoresin followed by the acidification of the resulting slurry to a pH of from about 2 to about 4 gives a slurry of the precipitated resin which may be filtered quickly.
Read the whole patent
Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Filed October 22, 1992 and granted August 12, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended October 22, 2012.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by October 22, 2014.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.