Controlled-porosity, calendered spunbonded/melt blown laminates
CA 2173327 C · Owner: E. I. Du Pont De Nemours And Company · Inventors: Lim, Hyun Sung; Shin, Hyunkook
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
Controlled porosity composite sheets comprising a melt-blown polypropylene fiber web (20) having a spunbonded polypropylene fiber sheet (10) laminated to at least one side thereof are made by calendering an assembly of the component webs in such a manner that when a, two-layer composite sheet is made the web of melt-blown fibers is in contact with a metal roll (1) heated to 140-170 °C operating against an unheated resilient roll (2) and, when a three-layer composite sheet is made the spunbounded web in contact with the heated metal roll has a dtex per fiber value of less than 6. These composite sheets have a Gurley-Hill porosity of about 5-75 seconds excellent mechanical and, tear strengths …
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 September 30, 1994 and granted August 10, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended September 30, 2014.
- A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by September 30, 2016.
- 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.