Abstract: The present invention relates to a process for the production of an optionally cellular elastomeric molded article having a compact surface and based on a polyurea elastomer containing urethane groups which is the reaction product ofa) a polyisocyanate component based on a polyisocyanate of the diphenylmethane series,b) a polyol component based on a polyether polyol, a polyester polyol or mixtures thereof andc) a polyamine component containing1) 50 to 95% by weight, based on the weight of component c), of at least one sterically hindered aromatic diamine and2) 5 to 50% by weight, based on the weight of component c), of at least one compound which has a molecular weight of about 1,000 to 12,000,by reacting component a) with at least 90% by weight of component b) at an NCO/OH equivalent ratio of at least 4:1 to form an NCO semi-prepolymer and subsequently reacting the NCO semi-prepolymer with component c) and the remainder of component b) by the reaction injection molding process to form the polyurea elastomer

Abstract: The present invention is directed to a process and apparatus for production liquid reaction mixtures. The invention includes a mix head with a mixing chamber which receives reactants through nozzle openings. The key feature resides in placing an impingement surface between at least one of the nozzle openings of the mix head and the mixing chamber itself.

Abstract: Plastics-forming materials are shaped in a mold tool sealed by an associated closing unit. Lifting elements the stroke of which can be limited and controlled are associated with the mold tool. Shaping is accomplished by filling the mold cavity with reaction mixture while the mold tool halves are not completely sealed, sealing the filled mold and keeping the mold sealed until the article is completely cured. This method and apparatus are particularly useful in the production of dimensionally accurate geometrically complicated shaped articles.

Abstract: A piston metering device for the production of a plastic material from at least two flowable reaction components. This device is basically composed of (a) a hydraulic driving mechanism, (b) two piston cylinder units, (c) a mixer head and, optionally, (d) a control device common to at least one of the piston cylinder units. This device permits rapid and simple adjustment of the metering ratio of reaction components by adjustment of throughput. Such adjustment is accomplished by means of regulating elements made of hydraulic motors rigidly coupled to one another.

Abstract: The invention is directed to a process for the production of a flowable reaction mixture from at least two flowable reaction components which comprises conveying said components from storage zones as main flows, metered in a predetermined ratio, to several mixing zones which are connected in parallel, said process further characterized in that the main flows are divided up in each case into a number of divisional flows corresponding to at least the number of mixing zones, which divisional flows are combined with each other in pairs, and the metering ratio of the divisional flows corresponds to the metering ratio of the main flows.

Abstract: The instant invention is directed to a method for producing hollow articles which are open toward the axis, are rotationally symmetrical and symmetrical with respect to a central plane produced from polyurethane multi-component reaction materials by the reaction casting method, a mold core being required during production for generating the cavity in the article, and the reaction mixture being supplied from the rotational axis via feed channels to a mold cavity, comprising: supplying a reaction mixture alternately to each side of the mold cavity, the article thus being built up symmetrically with respect to the rotational axis.

Abstract: The invention relates to a method and a device for producing a solid-forming or foam-forming flowable reaction mixture by metered injection of flowable reaction components into a mixing zone from which the finished reaction mixture is discharged.

Abstract: The invention relates to a method of filling cavities and, in particular, mold cavities, with a reactive solid-forming or foam-forming mixture, wherein at least two reactants are introduced into a spatially limited mixing zone, mixed therein as they pass through, and the mixture produced is introduced into a mold cavity where it reacts and wherein the mold cavity is initially enlarged in-part for storing a portion of the mixture, which portion is subsequently transferred to the final mold cavity volume. The object of the invention is to produce plastic articles which are shaped in molds, but also to fill out other cavities, for example, for the purposes of reinforcement.

Abstract: The present invention relates to a method and a device for producing shaped articles from a multi-component reaction mixture which forms, for example, polyurethane, epoxy resin, polyester resin or polyamide, by mixing at least two of the individual components in at least two premixing chambers to form multi-component reaction mixture and these mixtures are subsequently mixed in a single-stage mixing chamber to form a mixture which is introduced into a shaping zone in which it is cured to form the shaped article.

Abstract: The instant invention is directed to a method of producing a reaction mixture for forming solid or cellular materials from flowable reactants and, optionally, fillers, comprising premixing the components and, optionally, fillers in a first mixing zone and after-mixing in a second mixing zone, the improvement wherein said after-mixing is carried out in a slit-like annular zone which extends radially from the center, the surface boundaries of said annular zone are not parallel and one of said surface boundaries is rotated while the opposite facing surface boundary remains stationary.

Abstract: The instant invention relates to an apparatus for metering at least two flowable reaction components, such as polyurethane-forming components, in a predetermined ratio into a mixing chamber. The apparatus broadly comprises a metering unit for each component, which is made up of a piston and cylinder, a feed pipe leading from a storage container into the cylinder, a delivery pipe leading from the cylinder to the mixing chamber and optionally a return pipe, and a drive unit. Each drive unit is in the form of an electro-hydraulic linear amplifier which comprises a stepping motor for a control mechanism which is coupled to a hydraulic piston and cylinder, wherein the drive unit is capable of driving the metering piston. Control electronics are provided for controlling the metering units. The controls comprise at least one adjustable control frequency generator for generating signals to be fed to the electro-hydraulic linear amplifiers to control the movements of the metering pistons.

Abstract: A process is provided for introducing mixed foamable reactants to a mold. The process involves introducing the reactants into a mixing chamber through injection apertures in its side wall portion. The mixing chamber has an outlet aperture communicating with the cavity of the mold. Prior to introducing the reactants into the mixing chamber, a displacement piston having a smaller cross-section than the mixing chamber is inserted into the outlet aperture of the mixing chamber so that the injection apertures communicate with the mold cavity by means of a generally annular passage.

Abstract: This invention relates to an apparatus for dosing and mixing at least two fluid reactants consisting of a dosing unit; a mixing head and conduits connecting the dosing unit and mixing head; characterized in that the housing of the dosing unit and the mixing head together form a rigid block with the conduits connecting the dosing cylinder with the mixing chamber in the form of channels inside the block.

Abstract: An apparatus for mixing and molding a chemically foamable reaction mixture is comprised of a mold with a mixing chamber which has its outlet aperture in a wall of the mold and a displacement piston mounted in the opposite wall. An ejector piston is displaceable within the mix chamber and may be so channelled as to serve as a control piston. This ejector piston is displaceable from a position wherein the injection apertures lie between it and the mold cavity to a position wherein its end surface is flush with the mold wall. The displacement piston is so mounted that it may extend across the mold cavity and intrude into the outlet aperture of the mixing chamber. This displacement piston has a diameter smaller than the diameter of those portions of the mixing chamber into which it protrudes so that when this piston is within the mixing chamber an annular cavity is formed between it and the side walls of the mixing chamber. It is withdrawable to a position flush with the mold wall it protrudes through.

Abstract: A process for molding foam products substantially free from flaws caused by air bubbles in the foamable reaction mixture wherein a foamable reaction mixture having a viscosity .eta. in cP between 100 cP and 2500 cP is introduced into a mold cavity through an opening in the mold wall and against the wall of the cavity opposite the opening of a mold in which the thickness of the cavity and the thickness s of the resulting molded product adjacent to the opening at the time the mixture is introduced into the cavity is maintained at 0.5 mm to 15 mm under conditions whereby the radial distribution rate w.sub.radial in m/sec., .eta.

Abstract: Apparatus to practice the method of forming foam molded articles without the defects caused by incompletely mixed reactants in the mold cavity is provided. A mixing chamber bounded by a sidewall portion having injection apertures, an outlet aperture which communicates with the mold cavity and a first ejector piston displaceable within the bore of the mixing chamber is provided. Opposite said outlet aperture is a second ejector piston which is retracted at the start of the mold filling operation to provide a receiving chamber in the mold wall. As the mold filling proceeds, this piston is displaced towards the mold cavity until its end surface forms a planar surface with the mold wall. Optionally, this piston may be displaced into the mold cavity to eject the molded article.