ES352009A1 - Polycondensation procedure for the preparation of linear polymers of high molecular weight. (Machine-translation by Google Translate, not legally binding) - Google Patents

Abstract

In the production of linear high polymers, for example polyesters, by a process which comprises establishing a body of precondensate in a reaction zone, maintaining reacting conditions in zone for condesing, establishing at least one discrete planar film of reacting material from the body of precondensate, the or each film being exposed on both faces, causing reacting material in the or each film to flow freely downward under the action of gravity and continuously maintaining the film or films by adding material from the body of material, the process may be carried out in apparatus which comprises a chamber divided into a number of communicating reaction compartments spaced axially of the chamber, an inlet to the chamber for reacting material, an outlet from the chamber for reaction product, means whereby the compartments can be communicated to a source of vacuum, and at least one element disposed in each compartment, each element comprising a substantially annular disc mounted for rotation with shaft means and surrounding the shaft means in spaced relation therewith, each disc being substantially vertical in use of the apparatus and preferably being fastened to the shaft means by a spoke or spokes. As illustrated in Figures 1 and 2, the apparatus comprises a chamber defined by a stationary container 1 which advantageously is in the form of a doublewalled cylinder having double-walled ends 2 and 3. Located in the lower part of the container to extend to the middle thereof are stationary partition walls 4 which define reaction compartments spaced axially of the container connected one to each of the end compartments is an inlet 5 for reacting material and an outlet 6 for reaction product, to which outlet a discharge element, for example a worm (not shown), preferably is attached. Passing in vacuum-tight manner through the ends of the container to be coaxial therewith is a drive shaft system 7 rotatably supported in stationary bearings 8 and 9 located outside the container, the end 10 of the shaft system being connected to a rotating drive, for example an electric motor provided with a variable speed gear (not shown). The container is supported by feet 11. Located above the partition walls to be common to all the reaction compartments is a vapour space 12 from which a conduit 13 leads to a source of vacuum (not shown). Elements in the form of annular discs 14 are fastened to the shaft system by means of hubs 15 and spokes 16. The annular width of the discs preferably is from 0.0- to 0.2 times the internal diameter of the container the distance between the internal wall of the container and the discs preferably is at least 0.01 times the internal diameter of the container the distance between the partition walls preferably is from 0.1 to 0.4 times the internal diameter of the container. The compartments which will contain reacting material and reaction product of lower viscosity may be provided with correspondingly more discs. As illustrated in Figures 3 and (not shown), those compartments nearer to the inlet each contain two discs as illustrated in Figures 5 and 6 (not shown), those compartments nearer to the inlet and those compartments axially central of the container respectively each contain three discs and two discs. For continuous operation of the apparatus, that compartment adjacent the outlet preferably is not provided with a disc for batchwise operation of the apparatus, that compartment adjacent the outlet preferably is provided with a disc. The apparatus may include means whereby the peripheral speed of the discs will decrease from the inlet end of the container towards the outlet end of the container, i.e. as the viscosity of the material within the container increases. As illustrated in Figures 7 and 8 (not shown), the shaft system comprises a number of coaxial shafts each of which may be driven at different speeds by a gearbox having pairs of gearwheels which provide different transmission ratios as illustrated in Figures 11 and 12 (not shown), the shaft system comprises two separate coaxial shafts extending into the container from opposite ends thereof and having separate drives for rotating the shafts at different speeds. Alternatively, the diameter of the discs may decrease from the inlet end of the container towards the outlet end of the container, for example by tapering the container from the inlet end thereof to the outlet end thereof as illustrated in Figures 13 and 14 (not shown) and in Figures 15 and 16 (not shown), the container is frusto-conical and of stepped configuration, respectively. As illustrated in Figures 9 and 10 (not shown), the shaft system is eccentric with respect to the longitudinal axis of the container, the discs being closest to the wall of the container in the lower part of the container. Figures 17 to 24 (not shown) illustrate various partitions walls Figures 25 to 28 (not shown) illustrate discs having respectively on, two, three or four integral spokes for attachment to the shaft system. The process and apparatus are exemplified with reference to the continuous (Examples 1, 2 and 3) and batch-wise (Examples 4 and 5) production of polyethylene terephthalate (see Abridgmenrit for Division C3).