摘要:
Pulverulent polymers of acrylic acid and methacrylic acid are prepared by polymerizing (a) from 100 to 70% by weight of acrylic acid, methacrylic acid or a mixture thereof and (b) from 0 to 30% by weight of vinylsulfonic acid or an alkali metal salt thereof in a monohydric C.sub.1 -C.sub.8 -alcohol, water or a mixture thereof in a pulverulent bed in the presence of a polymerization initiator and from 0.05 to 10 mol % of thiocarboxylic acid and/or a mercaptoalcohol and from 0.05 to 10 mol % of propionic acid or formic acid as regulators, each percentage being based on the monomers used in the polymerization, by maintaining the pulverulent state during the polymerization, removing the heat of polymerization by distilling off the solvent and recirculating the reaction mixture.
摘要:
Maleic anhydride copolymer powders are prepared by a process wherein a solution or dispersion of maleic anhydride in an alkyl vinyl ether and/or an alkene, containing from 3 to 25 moles of the alkyl vinyl ether and/or alkene per mole of maleic anhydride, is brought into contact with a powder bed under polymerization conditions, and is polymerized in the bed while the reaction mass is circulated and the powder state is maintained, and the heat generated during polymerization is removed by evaporating excess monomer which boils lower than maleic anhydride.
摘要:
Concentrated, stable water-in-oil emulsions of water-soluble or water-swellable polymers are prepared by polymerization of one or more water-soluble ethylenically unsaturated monomers in a water-in-oil emulsion and removal of water from the water-in-oil polymer emulsion by azeotropic distillation, by a method in which superheated vapor of an inert organic solvent which is immiscible with water is passed into the water-in-oil polymer emulsion. Using the process, it is also possible to concentrate emulsions which tend to coagulate or water-in-oil emulsions which are sensitive to shearing, without the polymers losing their effectiveness.
摘要:
The invention relates to a measuring sensor having pump reference for measuring the oxygen content of gas mixtures, particularly exhaust gases of internal combustion engines. The sensor includes a measuring cell (A) and a reference cell (B) each having a pair of electrodes, with one of each respective pairs of electrodes being common to the two cells, and having a fixed electrolyte. Reference cell (B) has defined therein an internal oxygen reference zone which is hermetically sealed from the gas mixture and which is connected to the atmosphere by way of a pressure-equalization line. The measuring cell (A) and the reference cell (B) can be heated by heating apparatus to a temperature at which the fixed electrolyte has an ionic conductivity which is sufficiently high. The heating apparatus and a porous insulation are advantageously disposed in the vicinity of the electrode of the reference cell which is not in common with the measuring cell and which is porous so that the porous insulation, together with the porous electrode, form the internal oxygen reference zone and, together with the porous electrode and its porous conductor track, form the pressure-equalization line.
摘要:
To reduce the width of the groove (6,7) within which the end portions of rubber blankets (14) of a blanket cylinder are attached, and thus prevent oscillations occurring due to roll-off of the groove against another cylinder, which may likewise have a groove, the rubber blanket is formed to have a reinforcing strip which is shorter than the axial dimension of the rubber blanket, the rubber blanket being formed with converging sides, the slot width of the groove adjacent the circumference of the cylinder being narrow in the end regions to have the width of only about twice the width of the thickness of the rubber blanket. In some constructions, the rubber blanket is a composite blanket formed of a substrate and an ink transferring cover; the end portion of the rubber blanket, which fits within the groove, can be left free of the ink transferring rubber cover so that the width of the slot at the end portion can be narrowed even further to only about twice the width of the substrate. The slot, or at least the central portion (11) thereof, can be slightly inclined with respect to a central axis (A-A) of the cylinder about which the blanket is to be stretched.
摘要:
To prevent buckling of a lowermost one, or a lower group of superposed webs being fed, in superposed relation to a common folding triangle or folding former (1), a driven supply roller (2) is provided which has its circumference formed with projecting pins (6) or the like, long enough to penetrate through the entire stack of the superposed web (8) as it runs over the supply roller, thereby feeding all the webs at the same speed to the folding former. Preferably, a hold-down roller (9) is provided, formed with a circumferential groove (10) aligned with the pins (6) so that the pins can penetrate through the webs and fit into the groove (10).
摘要:
To reliably hold a sheet in a rotary sheet-fed offset printing machine, a plurality of pin or needle-like projections (11), preferably held on a holding strip (12), are located transversely just behind or beneath the grippers. The sheet is pressed against the pins by the rubber blanket of the blanket cylinder, to impale the sheet on the pins; or, if the projections are located beneath the grippers, the grippers indirectly apply pressure on the sheet to impale the sheet on the projections. In another embodiment (FIG. 6), a pressure block (13) with a resilient engagement surface (14) presses the grippers on the sheet for also impaling the sheet on the pins or needles. The projections may also be formed as knife edges (FIG. 4). Alternatively, the printing line can be shifted forwardly (FIG. 5), so that the rubber blanket will engage the ends of the grippers.
摘要:
Individual ink disk or roller elements (4) are located, axially positioned next to each other on a roller transfer structure; to provide for smooth operation of the ink train rollers, the disks or roller elements of the ink roller structure are in continuous surface engagement with an ink-receiving roller (5) forming part of the roller train, and driven at machine speed, and selectively shiftable about its circumference, by deflection of individual angled levers (6) for selective engagement with a ductor roller of an ink supply, leaving, however, a gap or nip (x) for ink transfer from the ductor roller. The stroke of the deflection of the individual angled levers is adjustable by adjustable stop elements (7; 12, 13, 17', 22) to control the width of the gap or nip between the ink disks or roller elements (4) and the ductor roller, when the disks or roller elements are moved toward the ductor roller.
摘要:
To sense the ink density, in zones, transversely of a plate cylinder while avoiding possible erroneous determination due to transport of contaminants such paper dust or fluff, from the blanket cylinder to the plate cylinder, the attachment groove for the blanket (4) of the blanket cylinder (2) is made wider than the attachment groove (10) for the plate (3) of the plate cylinder (1), to leave a transverse strip (A) extending across the plate, on which sensing fields (12) are applied, for example by printing-on; the sensing fields, located in adjacent zones (Z) will be inked by the inking system (25) of the printing machine and, since out of contact with the blanket, will remain uncontaminated. A densitometer (13) sensing the inking density in the respective fields is translated across the printing cylinder, and sensed values are associated with the measuring fields (12), for example by determining rotation (n(sync)), permitting control of adjustment screws of a doctor blade (24) by suitable servo motors (23).
摘要:
To insure accuracy in feeding a sheet of paper from an overlapped, shingled paper supply on a make-ready table, a suction pick-up picks up the sheet and moves it upwardly for a limited distance of about 1 mm before initiating the forward movement of the sheet to transfer it to a gripper mechanism of a printing cylinder or transport drum while, simultaneously, moving it transverse to the plane of the sheet to bring it into proper alignment with the drum or cylinder gripper mechanism.