Abstract: Angular blocks of foam flocks can be produced with angular edges and a homogeneous density distribution over the entire cross-section in a molding box by first extending the of adjacent mold walls before the flocks are introduced, and, after the flocks have been introduced, reducing it to the envisaged cross-section of the slab to be produced. Wherein, at every corner formed by two adjacent mold walls, one of the mold walls is divided into a wall part and a flap held thereon which can be moved around a swivelling axis perpendicular to the base and can be swivelled between a position pointing outwards and a position parallel with the wall part.

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: Angular blocks of foam flocks can be produced by the composite process with angular edges and a homogeneous density distribution over the entire cross-section in a molding box by first extending the filling cross-section in the comers of adjoining mold walls before the flocks are introduced, and, after the flocks have been introduced, reducing it to the envisaged cross-section of the slab to be produced and thus filling hollow spaces, and compacting the flock filling to the desired density in the comers, so that the slab has a homogeneous density over the entire cross-section.

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: The present invention relates to a high-pressure mixing head for mixing at least two reactive plastic components, containing a mixing chamber, into which there lead two injection nozzles arranged opposite one another for the components, a proportioning piston which is displaceable in the mixing chamber and a settling and outflow chamber with a cleaning slide extending substantially perpendicular to the axis of the mixing chamber, characterized in that the settling chamber and the cleaning slide have a substantially rectangular cross-section with an axial ratio from 10 to 100. The axial ratio is defined as the ratio of the width of the settling chamber and the cleaning slide to the thickness of the settling chamber and cleaning slide.

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 device for removing plastics residue from a cleaning piston having an end face and a mixer head outlet pipe of a counter-current injection mixer head, wherein the device comprises a stripping plunger having a stripping edge; a mortar for receiving the stripping plunger, the mortar comprising an outlet opening for disposing the plastics residue from the mortar which is disposed at an angle to an impact face of the mortar; a hydraulic device for bringing the mixer head and the stripping plunger towards each other in the cleaning position, in which the stripping edge of the stripping plunger is aligned with the end face of the cleaning piston, wherein the axis of the cleaning piston is situated between the mortar and the stripping plunger; and a hydraulic device for moving the stripping plunger parallel to the end face of the cleaning piston into the mortar and towards the impact face of the mortar.

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 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 and a device are described for the production of polyurethane foam by application of a froth onto the conveyor belt of a block-foam installation, whereby the froth is applied onto the lower conveyor belt in a free, substantially vertical fall and flowing of the froth contrary to the direction of movement of the conveyor belt is prevented by a stationary, substantially vertical barrier arranged transversely on the conveyor belt.

Abstract: A process is described for producing foam materials from two-component reactive plastics using carbon dioxide as blowing agent by mixing at least one of the reactive components with carbon dioxide under pressure, mixing the components, at least one of which contains carbon dioxide under pressure, expanding the reactive mixture containing carbon dioxide obtained by mixing, and hardening, wherein the expansion takes place suddenly with the production of high rates of shear. Preferably the rate of flow of the reaction mixture is reduced after expansion.

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: 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: 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: 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 valve for use in introducing a foamable reactive mixture into a cavity, with the valve being of such size that it can be positioned within the cavity and when so-positioned is in contact with at least one of the walls of the cavity, with the valve including:a) two essentially rotationally symmetrical coaxial cages, with said coaxial cages being spaced from each other, with the inner cage;i) having an axial opening for the introduction of the reactive mixture and at least two radial openings for the passage of the reactive mixture into the annular space formed between the inner and the outer cage; ii) having a ball, capable of moving freely within said inner cage and capable of closing the inlet opening following completion of the introduction of the reactive mixture; iii) having a convex surface opposite said inlet opening, with said convex surface being directed inward, so that during the introduction of the reactive mixture the ball assumes a position outside the inner cage axis; andb) with said outer cag

Abstract: When pulverising polyurethane, polyurea and/or polyurethane/polyurea materials in a roller mill with at least two rollers (2,3) rotating at different circumferential speeds, a very economical method of operation is achieved by returning the coarse fraction falling freely out of the roll slit (4) to the roll slit (4) and stripping the fine material adhering to the roller (3) with the higher circumferential speed and discharging it separately from the coarse fraction.

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.