摘要:
Disclosed is an agitator-free mixing head and a method for agitator-free production of a reaction mixture from an isocyanate and a higher-viscous polyol formulation, wherein both constituents are fed to a mixing zone and mixed with each other therein, whereby a polyol formulation with a viscosity of at least 3000 mPa.s is fed at low pressure into the mixing zone and at least two flows of low-viscosity constituents (isocyanate and optionally low-viscous polyol) are injected into the flow of high-viscous polyol formulation at high pressure.
摘要:
High quality, consistent polyurethane froth foams, both filled and unfilled, are prepared by directing polyol, isocyanate, and optionally other polyurethane-forming ingredients to a high pressure mix head (109) prior to introducing the mixture to a froth foaming head (121). Changes in stoichiometry may be made rapidly without shut-down. In one embodiment, an in-line blender (103) incorporates filler into the polyol stream minimizing density differentials normally encountered in the holding tank, maintaining low and reproducible viscosity, and allowing for greater amounts of filler than otherwise possible.
摘要:
Ein Verfahren und eine Vorrichtung zur Herstellung von Polyurethan-Schaum mit geregelter Zellenzahl, bei denen die Dispergierung von Gas (6) in einer der Komponenten Polyol oder Isocyanat in einer Dispergiervorrichtung (5) zwischen Mischkopf (1) und Dosierpumpe (3) für die jeweilige Komponente erfolgt.
摘要:
Das Verfahren zur kontinuierlichen Steuerung der Zellenzahl bei der Produktion von Polyurethan-Schaumstoffen aus Polyolen, Isocyanaten und Wasser, wobei die Vermischung der Komponenten in einem Mischkopf mit einstellbarem Einspritzdruck und einstellbarem Mischkammerdruck erfolgt, besteht darin, daß unmittelbar vor dem Eintritt in den Mischkopf der Gasgehalt des Isocyanats kontinuierlich erhöht oder vermindert wird.
摘要:
A method for the preparation of flexible polymeric foam by reacting a polyisocyanate component with an isocyanate-reactive component comprising at least 50 % by weight of water, the polyisocyanate component comprising at least two polyisocyanate compositions, one of them being a low NCO isocyanate terminated prepolymer and the second being a high NCO polyisocyanate.
摘要:
A method of producing a polyurethane foam comprising the steps of dissolving rapidly and substantially completely a non-condensible non-reactive gas in a liquid isocyanate component or a liquid polyol component or both while the isocyanate and polyol components are maintained separate from one another, while controlling the flow of the non-reactive gas to maintain a predetermined dissolved gas to liquid ratio, and while maintaining the component in which the nucleating agent is being dissolved under pressure sufficient to maintain the gas in solution and to hold substantially constant the dissolved gas to liquid ratio and mixing the previously separated isocyanate and polyol components together while reducing the pressure to nucleate the dissolved gas in the isocyanate and polyol components and while impinging liquid streams of the composition together thereby enhancing mixing and permitting the mixture to foam so as to form a fine celled polyurethane foam. An apparatus for producing the same is also provided.