Abstract: Process for continuous production of polyesters by esterification of terephthalic acid with 1,4-bis(hydroxymethyl)cyclohexane with a split feed in the presence of a titanium catalyst at 265.degree. to 305.degree. C. and 0.8 to 1.5 bar up to a conversion of 98.0% to 99.0%, then performing precondensation at 290.degree. to 305.degree. C. and 0.01 to 1.5 bar up to a conversion of 99.4% to 99.7% and finally performing polycondensation at 295.degree. to 310.degree. C. and less than 1.5 mbar up to a conversion corresponding to 50% to 95% of the maximum possible viscosity after adding more titanium catalyst.

Abstract: Process for discontinuous production of polyesters by esterification of terephthalic acid with a definite excess of 1,4-bis(hydroxymethyl)cyclohexane in the presence of a titanium catalyst at 180.degree. to 300.degree. C. and 0.8 to 1.5 bar up to a conversion of 98.0% to 99.6%, then precondensation with the addition of more titanium catalyst at 270.degree. to 300.degree. C. and 500 to 5 mbar up to a conversion of 99.5% to 99.9% and polycondensation at 295.degree. to 310.degree. C. and less than 1.5 mbar up to a conversion corresponding to 40% to 95% of the maximum possible viscosity.

Abstract: Polyethylene terephthalate having an acetaldehyde content of less than 2.5 ppm and suitable for packing of food and beverages intended for human consumption is produced by heating polyethylene terephthalate having an intrinsic viscosity of about 0.5--0.85 at a temperature of 180.degree.-230.degree. C., preferably 200.degree.-220.degree. C., for about 4 to 12 hours. The polyethylene terephthalate must not include more than 25 ppm of ester interchange catalyst or 20 ppm of phosphorous during this heating.

Abstract: A nozzle of a dyestuff applicator has a cylindrical valve housing formed with an orifice obstructable by the tip of an electromagnetically displaceable needle which controls the outflow of dyestuff from a chamber in that housing. The chamber is sealed by a rubber diaphragm which is penetrated by the needle whose shaft is engaged by a pair of parallel membranes of spring steel peripherally clamped in an extension of the housing. Each membrane comprises a narrow outer ring with an inwardly projecting tongue split into two diverging branches which are interconnected at their free ends, near the diametrically opposite side of the outer ring, by a re-entrant web extending radially between these branches and terminating in an inner, needle-supporting ring concentric with the outer ring.

Abstract: A broad textile web, on its way to a processing station such as a rotary-screen printer, passes around a set of closely juxtaposed but independently rotatable feed rollers that are individually driven via respective differential gear trains each having a first input connected to a common drive shaft and a second input connected to an ancillary stepping motor. Each feed roller engages a strip zone of the web which is scanned by an associated sensor upstream of the roller, the latter detecting the leading and trailing edges of recurrent transverse web sections--e.g. of pile fabric--mechanically, electrically or optically distinguishable from intervening sections. Unequal longitudinal tensions in the several strip zones actuate the sensor-controlled stepping motors for different time periods so as to cancel any relative deformation.

Abstract: To produce a perforated metal foil, especially for use in a screen printer, a decomposable, dissoluble or vaporizable dielectric substance is deposited on a cylindrical conductive substrate in a dot pattern under the control of a photoelectrically scanned master. The spaces between the dots are then filled with an electrolytically deposited metal forming a coherent layer which is subsequently stripped off the substrate. The deposition of the dot pattern is carried out through a spray nozzle, sweeping the rotating substrate, which has an outlet in a bottom wall of a narrow space filled with the liquid dielectric to be dispensed, that space being separated by an apertured partition from an overlying plenum chamber in which the air is intermittently pressurized by an electromagnetic armature to expel a limited quantity of dielectric through the outlet; the membrane may be vibrated at supersonic frequencies to generate the necessary discharge pressure.

Abstract: A substrate to be patterned, such as a textile web, is moved past an array of nozzles with discharge orifices closely spaced from its surface, the substrate being firmly backed at locations confronting the nozzles by being drawn against a supporting conveyor or by being led around rollers. The nozzles are electromagnetically operated by needle valves, the valve needles being carried by membranes under substantially balanced pressures from the printing liquor and from a fluid such as compressed air. The electromagnetic coils are intermittantly energized by a programmed pulse generator with a large but brief driving current followed by a low holding current, the pulse generator including two complementary power transistors in series with a coil winding. A dyestuff applicator carrying one or more of such nozzles may be transversely displaceable across the substrate, under the control of a programmer, between intermittent advances of the substrate in its longitudinal direction.

Abstract: A continuous process and apparatus for remelting fluffy, high bulk tangled polymer waste, such as nylon or polyethylene terephthalate fibers, which comprises chopping the waste into pieces 15 to 40 mm. mesh size, passing the chopped waste through a charging zone, a compressing screw, and finally an extruder. The charging zone is formed by a vertically-disposed hopper, having two opposed parallel walls and two opposed converging walls. Inside the hopper is a plurality of agitating shafts having tapered fingers that loosen and disentangle the chopped waste. The waste then is compressed to one-fourth to one-fifth its volume and transferred to an extruder where it is melted, degassed and extruded to a predetermined shape.

Abstract: A substrate to be patterned, such as a textile web, is moved past an array of nozzles with discharge orifices closely spaced from its surface, the substrate being firmly backed at locations confronting the nozzles by being drawn against a supporting conveyor or by being led around rollers. The nozzles are electromagnetically operated by needle valves, the valve needles being carried by membranes under substantially balanced pressures from the printing liquor and from a fluid such as compressed air. The electromagnetic coils are energized by a generator of short current pulses separated by a low holding current, the generator including two complementary power transistors in series with a coil winding. A dyestuff applicator carrying one or more of such nozzles may be transversely displaceable across the substrate, under the control of a programmer, between intermittent advances of the substrate in its longitudinal direction.

Abstract: An apparatus and process for removing undesired monomers and oligomers from polyamide melt at subatmospheric pressure by passing steam through the melt to absorb the undesired components and carry them away. Various constructions are disclosed for vigorously intermixing the gas with the melt in which the gas is passed through a foraminous surface over which a thin film of melt flows, and a rotating agitator, spaced less than 50 mm from the surface, mixes the gas with the melt film. In a preferred form of the invention the rotating shaft comprising the agitator carries screw threads and serves as a conveyor for discharging treated melt from the pressure vessel in which the process is carried out.

Abstract: A two-stage process for making a linear condensate of phenol and formaldehyde which can be extruded as a film or thread. In the first stage phenol and formaldehyde are reacted at about 90.degree. C to produce a clear low-viscosity phenol-methylol liquid, the pH of which is adjusted to a value greater than 3, say between 3.5 and 7. In the second stage the product of the first stage is added in aliquot portions to molten phenol having a pH of 3 or less, while maintaining the temperature at about 100.degree. C. After all the phenol-methylol has been added the mixture is slowly heated as the viscosity increases up to about 150.degree. C until there is no further increase in viscosity. The highly viscous end product can be extruded as a film or thread.

Abstract: A printing machine with several groups of rotary-screen printing units, designed to print different color components of complementary portions of a recurrent pattern on an elongate web moving continuously beneath their screens, includes a programmer such as a perforated-type reader controlling the operation of the several printing units of each group in timed relationship dependent upon the web speed. A speed changer enables the peripheral velocity of the screens to be set at values different from the web speed, the timing of the printing operations being determined by two speed sensors upstream and downstream of the speed changer. These operations include a lowering of the rotating screen onto the web at the beginning of a printing cycle, a lifting of the screen off the web at the end of a working phase of that cycle, and a stoppage of screen rotation during part of the ensuing idling phase.

Abstract: A process for the continuous recovery of caprolactam from either solid polycaprolactam waste by depolymerization or from liquid polycaprolactam extraction water from an extraction zone where, in either instance, a caprolactam water vapor mixture is produced and subsequently upgraded in a distillation zone to provide a dilute mixture of caprolactam and water vapor. A minor portion of this dilute caprolactam water vapor is condensed and recycled to the distillation zone. The remaining, major portion of this mixture is compressed and admixed with fresh steam, superheated and passed to either the extraction zone or depolymerization reaction.

Abstract: A batch process for esterifying ethylene glycol and terephthalic acid at elevated temperature and pressure in which a part of the ethylene glycol required for the complete esterification reaction is placed in an autoclave and heated under pressure, and the remainder of the glycol is added to said heated glycol in the form of a paste with terephthalic acid. Preferably the glycol initially present in the autoclave amounts to 0.3 to 0.8 moles per mole of terephthalic acid while the glycol added as a paste amounts to 1.4 to 0.9 moles per mole of terephthalic acid. The glycol initially in the autoclave may be glycol reclaimed from the mixture volatilized during the reaction and may contain up to 20% water, preferably 2-6% water.

Abstract: A flexible apparatus and method for producing synthetic fibers in either the form of a single thread bundle on a bobbin, or as a combined thread strand in a storage can, without rearranging the spinning plant. This is accomplished by extruding the threads, one bundle from each of a series of aligned spinnerets, downwardly through ducts carrying a stream of air, and mounting directly beneath the ducts, in alignment therewith, an elongated take-up machine. The take-up machine has a row of winding devices on one side and a row of combining rollers on the other. The thread bundle from each spinneret is directed through a duct arrangement either to one side or the other of the take-up machine. All spinnerets may feed one side, or the other, or the production can be mixed with some spinnerets feeding one side and some the other, depending upon whether the market demand is for filament yarns or staple fibers.

Abstract: A separating or anticaking agent consisting of spherical glass particles having a diameter of 3 to 30.mu. is added to polyester resin granulates to prevent agglomeration during solid state polycondensation in a plug-flow reactor. Thin-walled articles formed from the end product are characterized by high strength, high transparency, crystal clear color, good gas impermeability and a smooth surface.

Abstract: This invention relates to a process for the continuous production of high molecular weight polyethylene terephthalate by polycondensation in the solid phase wherein granulated, dried polyethylene terephthalate, having an intrinsic viscosity of at least 0.15, is first crystallized and is thereafter subjected to solid state polycondensation.

Abstract: An alkali metal hydrogen monoglycolphosphate is added to the reaction product of diethylene glycol and dimethyl terephthalate to arrest the ester-interchange reaction and nullify the action of the divalent metal salt catalyst. These phosphates are easy to handle and convert the catalyst to an inactive compound which does not adversely affect subsequent polycondensation of the diethylene glycol terephthalate.

Abstract: A spinning unit for spinning fiber-forming polymers having a high pressure pump mounted on a pump base, and an interconnecting nozzle unit disposed adjacent said pump base within an insulated housing. A draw spindle threaded at one end and having a shoulder spaced from the threaded end, secures the pump base to the nozzle unit, the latter having a threaded opening to receive the threaded end of the spindle, the pump base having a wall against which said shoulder abuts to put the spindle in tension as it is tightened into said threaded opening.