Abstract: Process for generating a vacuum and separating the condensable components of the vapors of melt-phase polycondensation in the production of polycarbonate, where at least one or two vapor jets with a downstream spray condenser are connected to the intake side of the polycondensation reactor to be evacuated, and the motive vapor is diphenyl carbonate vapor, and the spray liquid is liquid diphenyl carbonate.

Abstract: Process for adjusting the haze value of ethylene terephthalate homopolymers and low-modified copolymers to a value in the range of 0.5 to 20 NTU while they are being produced by direct esterification and polycondensation, where an amount of antimony and germanium catalyst that is determined on the basis of the desired degree of turbidity is added before or at the start of the esterification step in the absence of other catalysts and other compounds that would affect the haze value, and after achieving a conversion of 90 to 98%, another dose of antimony catalyst corresponding to a total added amount of Sb+Ge in the range of 160 to 350 ppm is added, and then after addition of the catalyst is concluded, a phosphorus stabilizer is added to the reaction mixture in an amount to correspond to 0 to 50 ppm phosphorus.

Abstract: A process for the reduction of the carboxyl end groups of linear polyester through reaction with alkylene carbonate in the melt phase in the presence of 40 to 160 ppm of allyltriphenyl phosphonium bromide, based on the weight of the polyester.

Abstract: Process for thermal solid-state treatment of chips of saturated polyester, where the chips are crystallized immediately before the thermal treatment and the thermal treatment is carried out in a static bed at a chip temperature that is equal to TE (1 .mu.m) .+-.2.degree. C., where TE (1 .mu.m) is the temperature at which a measurement probe placed on a crystallized chip is lowered by 1 .mu.m under defined conditions in a thermomechanical analysis. The crystallization preferably takes place in a fluidized bed at three different specified temperatures.

Abstract: Distributors for viscous fluids, consisting of a central inlet line and at least two valves that are connected radially to the inlet line, each valve having one valve spindle that moves in the axial direction in the cylindrical valve casing and an outlet opening that opens into an outlet line, whereby a flow displacer having a cylindrical bottom part and a conical top part is inserted centrally into the inlet line at the level of the valves, forming a ring gap, and where the cross section of flow is constricted in the outlet opening and then immediately thereafter is enlarged in the outlet line.

Abstract: A process for filtering polymer melt which minimizes the generation of dead zones in the filter and provides uniform residence time and accurate temperature control. The process is carried out in an apparatus comprising a plurality of heat exchanger pipes, each enclosing a filter cartridge surrounded by an annular space which terminates at its upper end in a plurality of narrow channels. The molten polymer is charged into the annular space and divided into primary and secondary streams. The primary stream flows through the filter cartridge and the secondary stream, which constitutes 0.03 to 3.0 weight percent of the weight of the combined streams, flows through the narrow channels, whereupon the streams are combined and discharged from the apparatus. The discharge temperature of the polymer is maintained within .+-.1.degree. C. of the charging temperature and the heat exchanger fluid enters the apparatus at a temperature within 1.degree. and 5.degree.C. of the temperature of the melt.

Abstract: Process for multi-stage generation of a vacuum and condensation and recycling of the vapors of polycondensation in the production of polyester, where the last stage includes a liquid ring pump compressing to atmospheric pressure, a cooler and a degasifier tank. The process also includes at least two preceding stages each using a glycol vapor jet that is operated with superheated glycol vapor at a pressure in the range of 0.8 to 1.0 bar abs. and a downstream glycol spray condenser whose operating conditions are regulated to condense a maximum quantity of glycol and at the same time causing the low-boiling reaction by-products including water to remain in the gas phase.

Abstract: A polymer melt filtration apparatus comprising a closed upright cylindrical vessel divided by two horizontal pipe plates into a small lower product distribution chamber with a product inlet at the bottom, a small upper product collecting chamber with a product outlet at the top, and a large middle chamber connected to a heat carrier fluid circuit. A plurality of closely spaced heat exchanger pipes are mounted in the middle chamber between the pipe plates and surrounded by heat carrier fluid, each pipe enclosing a filter cartridge detachably connected at its upper end to said pipe and radially spaced therefrom to form an annular space around each cartridge. A series of narrow channels are provided between the upper end of the annular space and the upper collecting chamber to impede the generation of dead zones inside the annular space and the collecting chamber. The main polymer melt stream flows inside the pipes through the filter cartridges.

Abstract: Discontinuous catalytic process for the production of polyamide-6,6 by heating an aqueous AH-salt solution containing HPO.sub.3.sup.2- -ions, precondensing the solution with evaporation of water at 7 to 10 bar pressure and polycondensing in the melt phase, whereby the heating rate above 175.degree. C. of the AH-salt solution is at least in the range of 0.5.degree. to 3.0.degree. C./minute, the rate of evaporation of water is at least 2%/minute (based on the quantity of water in the AH salt solution). The total residence time for a polymer having a relative viscosity of 2.2 to 3.0 for heating from 175.degree. C., precondensation and melt phase polycondensation, is not more than 90 minutes.

Abstract: A process for the production of cellulose carbamate from cellulose and urea through the conversion of the cellulose with excess urea in an inert liquid organic reaction carrier at a temperature in the range of 130 .degree. to 160.degree. C., separation of the reaction carrier from the reaction mixture and washing of the reaction mixture with water. The cellulose is intimately mixed with an aqueous urea solution. Then the water in the solution is replaced with the organic reaction carrier, and the reaction of urea and cellulose is carried out in the presence of an inert gaseous carrier to remove the by-product ammonia. Thereafter, the organic reaction carrier remaining in the reaction product is replaced with an aqueous urea solution and the resulting suspension of cellulose carbamate in the urea solution is filtered and washed free of urea with water. No liquid ammonia is required in this process.

Abstract: A continuous process for the production of low-modified polyethylene terephthalate for food packaging in which, while maintaining specific processing conditions, a precondensate is polycondensed in the melt, the polycondensate is pelletized, and the pellets are first hardened, then crystallized and subjected to dealdehydization. The process results in a polyester having a very low acetaldehyde content.

Abstract: A process for producing spin-oriented continuous filaments at a draw-off speed of more than 2400 m/min, whereby the filaments extruded through the spinnerets of the spinning heads are cooled in cooling shafts by the ambient air entrained as a result of the suction action of the filaments and the filaments leaving the cooling shafts enter a chamber that is separate from the intake environment where the air pressure is regulated at a lower pressure in comparison with the air pressure in the intake environment.

Abstract: A process for producing spin-oriented filaments at a draw-off speed of more than 2400 m/min, whereby the filaments extruded from a spinneret are solidified in a cooling shaft solely by the ambient air entrained by the suction effect of the filaments and the cooling shaft having a zone where the walls are air permeable directly beneath the spinneret and has a following zone where the peripheral walls are completely closed.

Abstract: Process for the manufacture of a polyester masterbatch containing finely divided solid additives in homogenous and agglomerate-free distribution, through the mixing, within a homogenizing extruder, of the powdery additive into the polyester, whereby, separately from the addition of the additive, small quantities of a diol are additionally fed into the extruder.

Abstract: Discontinuous process for the production of polyamide-6,6 by heating an aqueous AH-salt solution, precondensing the solution with evaporation of water at 6 to 9 bar pressure and polycondensing in the melt phase, whereby the heating rate above 175.degree. C. of the AH-salt solution is at least 1.degree. C./minute, the rate of evaporation of water is at least 2%/minute (based on the quantity of water in the AH salt solution), the retention time for heating from 175.degree. C. and precondensation is not more than 75 minutes and the total retention time including polycondensation is not more than 120 minutes.

Abstract: A spinning block for the melt spinning of polymers, consisting of a melt channel, a coupling which is attached to the spinning bar and a nozzle block casing with a filter element and a spinning nozzle plate. A connector for detachably securing said nozzle block casing to the coupling consists of at least two bolts which are positioned symmetrically and perpendicularly to the axis of spinning, which bolts engage cooperating grooves, of a particular configuration, also positioned symmetrically and concentrically to the spinning axis. The bolts can be fixed to the casing or to the coupling. The grooves are provided in the coupling or the casing to complement the location of the bolts. By rotation of the nozzle block casing with respect to the coupling around the spinning axis, the parts are locked together.

Abstract: Process for simultaneous removal of aldehyde, solid-phase postcondensation and drying of linear polyesters and copolyesters by after-treating the polyester pellets with a diffusion surface of 1.95 to 2.90 m.sup.2 /kg, an individual pellet weight of 5 to 15 mg and a bulk density of 750 to 900 kg/m.sup.3 at 140.degree. to 210.degree. C. with a flow of a dry gas mixture consisting of 60-90 vol % N.sub.2, 5-21% O.sub.2 and 0.1-25% CO.sub.2 (total 100%) at a quantity ratio of 0.5 to 2.5 kg/h gas mixture per kg/h polyester.

Abstract: Distributor for viscous fluids with a feed line and multiple discharge valves and lines, each comprising a valve housing eccentrically enlarged opposite the discharge line and a valve piston with a hat-shaped valve head surmounted by a mushroom-shaped attachment. The valve piston may be positioned with respect to the eccentrically-enlarged portion of said housing to control the flow through the gap between the valve head attachment and the enlarged portion as compared with the flow through the gap between the attachment and the housing wall on the side adjacent the discharge line.

Abstract: Process for producing polybutylene terephthalate with less than 1.0 wt % units derived from ethylene glycol from polyethylene terephthalate scrap by diolysis and ester exchange with 1,4-butanediol and subsequent polycondensation.

Abstract: Modified copolyethylene terephthalate, for processing by extrusion blow molding, containing units of isophthalic acid, diethylene glycol and pentaerythritol, antimony and phosphorus plus small amounts of red toner and a blue toner. Also a process for producing same by direct esterification, melt polycondensation and heat treatment in the solid phase.