Abstract: A process for the preparation of polyisocyanates which contain one or more biuret groups, by reacting a) an aliphatic or cycloaliphatic isocyanate containing two or more isocyanate groups (isocyanate a) with b) a tertiary alcohol or a mixture of water and a tertiary alcohol (biuretizing agent b) at from 100 to 250° C.

Abstract: Mixtures comprise a) polyisocyanates (polyisocyanates A), comprising structural units selected from the isocyanurate and biuret group, derived from aliphatic or cycloaliphatic diisocyanates (diisocyanates C), b) non-A polyisocyanates (polyisocyanates B), comprising structural units selected from the allophanate and urethane group, derived from b1) aliphatic or cycloaliphatic diisocyanates (diisocyanates C) and b2) polyhydric aliphatic or cycloaliphatic alcohols (alcohols A), the molar ratio of the polyisocyanates A to the polyisocyanates B being from 200:1 to 5:1.

Abstract: A process for preparing biuret-functional polyisocyanates from at least one aliphatic or cycloaliphatic diisocyanate and from at least one amine or water or a mixture thereof as reactants involves mixing the reactants with one another in a mixing unit having a high shear action.

Abstract: Polyoxyalkylene polyols initiated with melamine and coinitiated with toluene diamine and oxyalkylated with one or more alkylene oxides have relatively low viscosity and are suitable for preparing polyurethane foams.

Abstract: The invention relates to a mechanism for selectively converting a continuous rotary movement in apparatus such as a high-speed-printing machine to a phase-related single pivoting movement of a control lever, with that single control movement following by an immediate reset to the initial position regardless of the time of activation of the mechanism. An entrainment lever supported on a supporting pin is coupled by means such as an excentric drive to the continuous rotary movement of the machine to generate a continuous pitching movement. A control lever is mounted for rotation on the same support pin and mounts a bistable mechanism (tensioning lever, pawl 3, tensioning spring 21) which in its first stable condition allows the entrainment lever to oscillate freely and which can assume its second stable condition when entrainment lever is in a dead center position, causing an engagement surface to be offered to the entrainment lever with the range of its pivoting movement.

Abstract: Plate changing apparatus for use with offset printing machines, including a plate stacking table, plate individualizing means for sequentially withdrawing only the lowermost plate from the stacking table, and plate transporting and guiding means to guide the freshly withdrawn plate to a form cylinder of the printing machine after having passed through a fixing bath. The apparatus includes means to pass the separated plate through a fixing bath prior to its deposit on the form cylinder and a depository for used plates removed from the form cylinder. The novelty resides in the individualizing means including a rotatable vacuum roll disposed adjacent a partly open bottom surface of the plate stacking table or container or tray holding the plates so that it can engage the lowermost plate. The vacuum roll has its shaft mounted in parallel with the leading edge of the plate stack for linear displacement in parallel with the bottom stack surface.