Abstract: For the production of polyurethane moldings by the shot process from isocyanate and polyol components, the production is improved in that, in addition to the conditioning already known for the line system, at least one of the commercially available but modified metering pumps is also conditioned in that some of the reaction component made available flows in circulation through the intermediate space between the enclosed metering component and housing of the pump.

Abstract: A process and a device are described for the continuous production of block foam by the foaming of a mixture which reacts to form polyurethane and which contains carbon dioxide dissolved under pressure, wherein the pressure of the reactive mixture is reduced on passing through a pressure reduction zone in the form of an aperture, and blockage of the aperture is prevented by the relative movement of the aperture-delimiting faces with respect to each other.

Abstract: A process is described for the continuous production of polyurethane block foam using carbon dioxide which is physically dissolved under pressure as a foaming agent, wherein before the polyol and isocyanate components are mixed the carbon dioxide is dissolved in the polyol component and air or nitrogen is dissolved in the isocyanate component, both components are fed to a mixing chamber in which a pressure prevails which is 70 to 150% of the solution pressure of the CO.sub.2 in the polyol component, the isocyanate component is fed to the mixing chamber at a pressure of at least 30 bar and is injected therein with depressurization down to the mixing chamber pressure, wherein air or nitrogen in an amount of at least 1 g per kg CO.sub.2 is dissolved in the isocyanate component, and after emerging from the mixing chamber the mixture is depressurization to atmospheric pressure.

Abstract: An installation for producing a three-dimensional shaped plastic foam part, comprises a plurality of tanks respectively receiving plastic foam granules and a liquid primary material, a device for reducing the plastic foam granules to a predetermined size, conduits connecting the reducing device to respective tanks receiving the plastic foam granules, a weighing tank having an inlet arranged to receive the plastic foam granules from the reducing device and an outlet, a device for mixing the plastic foam granules with the liquid primary material, further conduits connecting the mixing device to respective tanks receiving the liquid primary material and to the outlet of the reducing device, an intermediate storage tank comprising a weighing device and arranged to receive the plastic foam granules mixed with the liquid primary material, a mold having a mold cavity, and a supply line connecting the intermediate storage tank to the mold cavity, the supply line comprising a conveying device having an inlet and a con

Abstract: A method of producing a three-dimensional shaped plastic foam part comprises the steps of mixing plastic foam granules of a predetermined range of sizes and of different hardness in a predetermined mixing ratio to obtain a mixture of the plastic foam granules, mixing the mixture of the plastic foam granules with a liquid primary material until the granules are coated with the liquid primary material and a mixture of coated plastic foam granules is obtained, feeding a preset quantity of the mixture of coated plastic foam granules into a mold cavity of a mold closed on all sides, reducing the volume of the mold cavity at least in partial regions thereof after it has been filled with the mixture of coated plastic foam granules, triggering a reaction of the liquid primary material by applying pressure and heat until a continuous cellular structure of plastic foam has been formed and the plastic foam granules have been interconnected by the cellular structure of plastic foam after the volume of the mold cavity has

Abstract: A process and apparatus are described for the continuous production of polyurethane slabstock foam by applying a polyurethane reactive mixture in the form of a liquid foam from a substantially punctual source onto the conveyor belt of a slabstock foam plant and distributing the liquid foam transversely across the width of the conveyor belt by means of a distribution device arranged above the conveyor belt, to form a distribution slot, wherein the distribution device is in the form of a stationary plate.

Abstract: A process and device for the continuous production of slabstock foam by foaming a polyurethane reactive mixture containing carbon dioxide dissolved under pressure, comprising the steps ofa) feeding said polyurethane reactive mixture into a linear extended pressure distribution chamber at a pressure above that of the solubility vapor pressure of said dissolved carbon dioxide,b) reducing pressure to a pressure below said solubility vapor pressure of said dissolved carbon dioxide in a linear extended pressure reduction zone,c) feeding said polyurethane reactive mixture from said pressure reduction zone into a foaming chamber with a widening cross-section of flow to form a foamed reactive mixture, andd) applying said foamed reactive mixture (froth) substantially perpendicularly and free-flowing onto a conveyer belt of a continuous slabstock foam plant.

Abstract: A three-dimensional shaped part comprises at least one first portion having an equal density throughout the volume thereof and comprising a plastic foam of a primary material having a cellular structure and plastic foam granules interconnected by the cellular structure of the plastic foam, and at least one second portion having an equal density throughout the volume thereof, the second portion being adjacent the first portion and comprising a plastic foam of a primary material having a cellular structure and elastically precompressed plastic foam granules interconnected by the cellular structure of the plastic foam. 70% to 90% of the volume of the shaped part is formed by the plastic foam granules, and the density of the second portion is greater than the density of the first portion.

Abstract: A method and device are described for the production of foams from two-component reactive mixtures using carbon dioxide as expanding agent, by mixing at least one of the reactive components with carbon dioxide under pressure. That mixture is then mixed with the other reactive component(s) to form a foamable reactive mixture, which is expanded and cured to form the final product. The foamable reactive mixture is expanded to ambient pressure through at least one fine-meshed screen (21a, 21b, 21c).

Abstract: A process for the manufacture of polyurethane foam moldings is described wherein carbon dioxide physically dissolved under pressure is used as the blowing agent and a pressure is maintained in the mold cavity during the introduction of the polyurethane reactive mixture so as to prevent the complete release of the dissolved carbon dioxide.

Abstract: For the expansion of a liquid containing gas under pressure in dissolved form, it is proposed that the liquid be passed with expansion through an extended flow channel with a small cross-sectional measurement with generation of high rates of shear. The velocity of the liquid is then reduced prior to the foaming.

Abstract: An apparatus for preparing flowable reaction mixtures from at least two flowable reactants in which the components are injected into a mixing chamber by means of injection nozzles, the force of the reactant acting upon the nozzle needle is at least substantially compensated to avoid impairing the mixing ratio during a change-over of the nozzle needle. The rear end of the nozzle needle is provided with a chamber communicating with the component supply line.

Abstract: A method and device are described for the production of foams from two-component reactive mixtures using carbon dioxide as expanding agent, by mixing at least one of the reactive components with carbon dioxide under pressure. That mixture is then mixed with the other reactive component(s) to form a foamable reactive mixture, which is expanded and cured to form the final product. The foamable reactive mixture is expanded to ambient pressure through at least one fine-meshed screen (21a, 21b, 21c).

Abstract: The invention relates to a method and an apparatus for the continuous production of foam blocks or sheets having an essentially rectangular cross-section from a foamable, liquid reaction mixture, possibly in the form of a liquid froth, in which the reaction mixture is applied from a stationary mixing head onto a moving lower facing sheet inclined in the longitudinal direction. An upper covering sheet is supplied from above and is brought into contact with the reaction mixture by means of a deflecting element. The deflecting element is flat in the longitudinal direction, so that a channel with an essentially constant cross-section is formed between the lower facing sheet and the upper covering sheet guided by the deflecting element, the length of which channel in a longitudinal direction is several times greater than its central height H.sub.M. The deflecting element can be oscillated about an axis at the entry end where it rests on the reaction mixture by the application of pressure.

Abstract: For the expansion of a liquid containing gas under pressure in dissolved form, it is proposed that the liquid be passed with expansion through an extended flow channel with a small cross-sectional measurement with generation of high rates of shear. The velocity of the liquid is then reduced prior to the foaming.

Abstract: The invention is directed to an apparatus for the production of polyurethane moldings endless in one dimension using at least two alternately operated mixheads for the reactive polyurethane components. Material which has been correctly conditioned by circulation of the reactive components through the mixhead not in operation arrives at that mixhead at least before it is put into operation and the components are delivered by units which are common to the mixheads, but independent of one another in regard to "mixing" and "conditioning".

Abstract: A method and apparatus for continuously dispersing fine particle-sized solids in liquids by a continuous process, in which a constant stream of liquid is fed into a mixing apparatus and fine-particle-sized solids are metered into the mixing apparatus by means of a metering screw as a function of the pressure prevailing in the mixing apparatus. The solids conveyed by the metering screw are supplied from an intermediate vacuum tank with a controlled filler level.

Abstract: The invention relates to a method and an apparatus for producing polyurethane foam with a controlled number of cells, in which a gas is dispersed in one of the components, i.e. the polyol or the isocyanate, in a dispersing device arranged between the mixing head and the metering pump for the respective component.

Abstract: The maintenance of the exact metering ratio during the production of plastics, particularly foams, from free-flowing reactants loaded with pulverulent to fine-grained or fibrous additives can be improved by mixing the additive in compacted form in a preliminary mixer with at least one of the reactants. The pressure in the preliminary mixer is kept constant.

Abstract: In the production of a flowable reaction mixture of at least two flowable, also not readily miscible, reaction components which react completely with each other to form solid substance or foam material, a rapid abatement of the mixture flow is achieved with a compact type of construction after causing throttling at the discharge of the mixing chamber.