Bleaching of a paper web with peroxide
CA 2134072 A1 · Owner: Upm-Kymmene Oy · Inventors: Johansson, Markku T. O.; Hassi, Heikki Y.; Teittinen, Outi-Maija K.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The invention relates to a method for bleaching a paper web with peroxide and to a paper surface treatment mixture intended for such a method. According to the invention peroxide is introduced, onto a moving paper web as part of the said mixture which in, addition to the peroxide contains another active component such as a, bonding agent or a surface coating to be introduced onto the, web. The bonding agent may be made up of starch and a surface coating pigment, such as calcium carbonate kaolin or talc. Peroxide, is added to these so that its amount on each side of the web to be bleached will be approx. 0.08-1.0 g/m2.
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 April 23, 1993. No grant is recorded for it in Canada; had it been granted, its 20-year term would have ended April 23, 2013.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by April 23, 2015.
- 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.