Film-forming size composition
CA 2017250 C · Owner: Ortega, Theresa M. · Inventors: Dial, Harold D.; Clare, Kenneth; Ortega, Theresa M.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A film forming composition useful as a paper size is described which includes 1-20 parts, preferably 2-15 parts by weight of a gum selected from the group consisting of xanthan gum, rhamsan gum, welan gum and mixtures thereof; 3-20 parts, preferably 5-17 parts, by weight of a water soluble alginate; and 60-100 parts, preferable 70-90 parts by weight of starch, polyvinyl alcohol or carboxymethylcellulose with the gum:alginate ratio being not greater than 1:1, preferably not greater than 1:2. The balance of the composition will primarily be water. Additives such as sodium hexametaphosphate may also be present.
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 May 22, 1990 and granted January 30, 2001. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended May 22, 2010.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by May 22, 2012.
- 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.