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: 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: Filler-containing molded parts or articles are produced from a free-flowing reaction mixture, e.g. of polyol and isocyanate, in a manner which permits the changeover to a different filler content to be carried out more rapidly and, possibly, without material loss. This is achieved by dividing at least one of the reaction components into at least two portions, at least one of which is charged with filler, by adjusting the mixing ratio of these portions and hence the filler content of the finished molded part. At least two storage vessels are provided for at least one of the reaction components. Adjustable metering devices are arranged between these two storage vessels and the mixing device.

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: 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 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 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: 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: 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 and device for foaming casings, particularly refrigerator casings, with a blowing agent which can form an explosive mixture with atmospheric oxygen during evaporation which reduce the risk of explosion by introducing inert gas into the space in which the foam is to be formed by means of a servo-controlled inlet valve.

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: In a fine comminution apparatus arranged downstream of a coarse comminution apparatus, polyurethane foam wastes can be comminuted to the desired particle size for recycling as an additive in the production of polyurethane, in a low-dust and energy-saving manner, by carrying out the fine comminution preferably by repeatedly forcing a mixture of the coarsely comminuted material and one of the reaction components through a nozzle or through a plurality of nozzles.

Abstract: A process and apparatus are described for the production of a flowable reaction mixture from at least two flowable reactive components which may be difficult to mix, which components react with one another to form a solid or a foam material. The components are injected into a mixing zone where the components are mixed in a continuous flow. The mixture flowing from the throttling zone is divided into two sub-streams which flow around a piston and which recombine opposite the division point.

Abstract: The variations in the delivery rate of additive caused by fluctuations in a system for the preparation of a polyurethane reaction mixture from flowable reactants and an additive, in particular a blowing agent, are kept within negligible limits by subdividing the supply pipe (4) to the mixing head (6) into a main pipe (8) and a subpipe (9) and introducing the additive into the side stream, which is substantially smaller than the main stream.

Abstract: In the production of a reaction mixture which forms plastic material, in particular foamed plastic material, from at least two flowable reaction components, the inlet members or other switch-over members which must be switched over in a precise fashion, and controlled by a sliding valve comprising a slide which is assigned a restoring spring which operates in opposition to a moving electromagnet, and a holding electromagnet. First, the holding electromagnet is fully activated whereupon the moving electromagnet is activated. Following the build-up of force of the moving electromagnet, the holding electromagnet is switched off so that the inlet member or other switch-over member opens abruptly.

Abstract: The invention is directed to a filter device for the removal of coarse components from a liquid component used in the manufacture of plastic materials. The filter device has a hollow housing in which a rotor is mounted. The rotor is provided with agitator blades which comb out any dead-flow zones.

Abstract: In order not to have to rinse, during breaks in production, oscillating mixheads such as are used for the manufacture of free-flowing, plastic-forming reaction mixtures, an exchangeable insert part held in position by means of a clip and preferably consisting of plastic material is provided in the mixhead. The insert has a mixing chamber and an outlet channel. This insert part can be disposable or reusable.