Process for preparing polyurethane foams having zones of differing hardness
CA 1283765 C · Owner: Tenhagen, Rudolf Johann · Inventors: Lidy, Werner August; Tenhagen, Rudolf Johann
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
A process for preparing a polyurethane foamed article comprising a hard foam encapsulated by a soft foam is provided. The process provides improved encapsulation over that described in EP 68820 by frothing the hard foam formulation with for, example carbon dioxide, before it is introduced onto the rising soft foam formulation. The hard foam formulation is frothed so that it's density is between 75% and 145% of the soft foam formulation.
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
- Granted May 7, 1991. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended May 7, 2008.
- 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.