Bayer Aktiengesellschaft

Walter Schneider

Heinrich Boden

Klaus Schulte

Wilfried Ebeling

Ulrich Knipp

Wolfgang Reichmann

Heinrich Ersfeld

Adolf Richartz

Klaus Nadolski

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.

Method and an apparatus for the production of shaped articles

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.

Piston metering device for the production of plastic material from at

A first reaction mixture, prepared from (a) isocyanates with isocyanate contents of from 5 to 50% and (b) compounds with molecular weights of from 32 to 10,000 which contain at least two isocyanate-reactive hydrogen atoms, in an equivalent ratio of component 'a' to component 'b' of 0.8:1 to 5:1, from 0.1 to 20% of a blowing agent and, optionally, other known additives, is introduced into the rigid cavity of a closed mold. After this mixture has become resistant to permeation, but is still compressible, a second reaction mixture, either the same or different from the first reaction mixture, prepared from (c) isocyanates having isocyanate contents of from 5 to 50% and (d) compounds with molecular weights of from 32 to 10,000 which contain at least two isocyanate-reactive hydrogen atoms, in an equivalent ratio of component 'c' to component 'd' of from 0.8:1 to 5:1, specific internal mold release agents and optionally blowing agents and other additives, is introduced into the mold, such that it surrounds the first mixture and compresses it. A third, optional, reaction mixture, the same as or different from the second mixture, may also be employed in a manner similar to the introduction of the second mixture. The final composite plastic part releases smoothly from the mold.

Process for the production of a cellular composite plastic part

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. The invention is also directed to an apparatus for the production of flowable reaction mixtures from at least two flowable reaction components comprising storage containers from which supply lines lead via metering pumps to at least three mix heads which are positioned in parallel, further characterized in that one metering pump is provided for each reaction component, and flow dividers consisting of parallel-positioned elements are provided between these metering pumps and the mix heads in the supply lines.

Process and apparatus for the production of a flowable reaction mixture

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.

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Overath, Germany

Walter Schneider