Fabric useful as a concrete form liner
CA 2098119 C · Owner: E. I. Du Pont De Nemours And Company · Inventors: Serafini, Franco Luigi
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Concrete forms utilizing an improved concrete form liner comprising a two-sided fabric having a different range of pore sizes on one side compared to the opposite side. In one embodiment a microporous coating, such as an ethylene-vinyl chloride microfoam dispersion, is placed on one side of a porous fabric (13) to controllably reduce the pore size of the fabric (13) on that side to between 0.2 to 20 microns. The coated fabric is used in combination with a support (11) and a grid (12) to form a concrete casting system (10) wherein the coated side of the fabric (13) is placed directly in contact with the concrete. The microporous coating stabilizes the surface fibers of the fabric (13) …
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 December 10, 1991 and granted December 2, 1997. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended December 10, 2011.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by December 10, 2013.
- 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.