Froth system for continuous manufacture of polyurethane foam slab-stocks
AssigneeFoaming Technologies Cardio BV
InventorsCarlo Fiorentini, Anthony C. Murray Griffiths
Life of this patent
Estimating the term…
Abstract
A process and a system for the continuous manufacture of polymeric foams. Reactive chemical components and additives comprising a low boiling blowing agent are mixed under pressure; the mixture is then frothed before chemical reaction takes place by feeding the mixture through a pressure equalizing and frothing device having a pressure-drop zone opening into a frothing cavity having an output aperture to discharge the froth onto a moving substrate.
Claims14
A system suitable for the continuous production of polymeric slab-stock foam on a moving substrate comprising:
- a mixing device for mixing reactive chemical components and liquid CO.sub.2 blowing agent under pressure,
- a feed line for carrying the mixture to a frothing device comprising a pressure equalizing chamber provided with a pressure drop zone dimensioned to maintain back pressure on the upstream mixture to keep the liquid CO.sub.2 in a liquid state and to initiate frothing under pressure controlled conditions to avoid turbulent evaporation of the blowing agent upon discharge of the mixture from the pressure drop zone, and
- a frothing cavity having an outlet aperture extending transversely across the moving direction of the substrate and forming the discharged mixture into a progressively non-reactive expanding frothing material by progressively releasing the CO.sub.2 in the frothing material as the frothing material flows along the frothing cavity.
A system for continuously producing low density, flexible polyurethane slab-stock foam on a moving substrate comprising:
- a mixing device for mixing reactive chemical components and liquid CO.sub.2 as a blowing agent under pressure;
- a feed line for carrying the mixture to a frothing device comprising a pressure equalizing device provided with a pressure-drop zone dimensioned to maintain back pressure on the upstream mixture to keep the liquid CO.sub.2 in a liquid state and to initiate frothing under pressure controlled conditions to avoid turbulent evaporation of the blowing agent upon discharge of the mixture from the pressure drop zone;
- and a walled frothing cavity extending from said pressure equalizing device, said walled frothing cavity being defined by walls that confine and permit the discharged mixture to develop into a progressively non-reactive expanding frothing mixture by progressively releasing the CO.sub.2 in the frothing material as the frothing material flows along the frothing cavity, said frothing cavity terminating at an outlet aperture for distributing an expanding frothing mixture onto and in the moving direction of the substrate.
A flexible foam slab-stock plant comprised of a pressurized chemical mixing station for mixing polyurethane chemicals together with liquid CO.sub.2 as a low boiling blowing agent maintained in a liquid state to produce a polyurethane foam material, a discharge assembly connected to said chemical mixing station for receiving the mixed polyurethane chemicals and for developing the mixture into a homogeneous progressively pre-expanding non-reactive froth material and depositing an expanding non-reactive froth material onto a substrate moving along a fall plate, and a conveyor assembly positioned relative to said fall plate for receiving the froth material discharged from said fall plate, said conveyor being operated at a rate of about 1 to 5 meters per minute so that the mixed polyurethane chemicals can react with full block height being achieved within a range of about 1 to 8 meters from the deposit point.
Dependencies are inferred from the claim text.