DE10329971A1 - Solid state polycondensation process, e.g. for preparing polyesters for fiber production, involving supplying reactor with raw material granules obtained from threads or strands having structured cross-section - Google Patents

Abstract

In a polycondensation process involving supplying granules (G) of = 2 mm to a polycondensation reactor (1) in which the raw material of (G) is supplied with energy and converted into a macromolecule by cleavage and elimination of low molecular components. In a polycondensation process involving supplying granules (G) of = 2 mm to a polycondensation reactor (1) in which the raw material of (G) is supplied with energy and converted into a macromolecule by cleavage and elimination of low molecular components. The condensed raw material is shaped into threads or strands of a structured cross-section to give an increased surface for the action of energy and the cooled threads or strands are cut (4) into (G) to be fed to the reactor.

Description

at The polycondensation is known, in contrast to the polymerization a reaction between simple molecules, whereby through the condensation In several stages with energy supply new, larger molecules emerge and small, simple ones molecules be split off. In this way, for example, polyester, phenolic, Aminosplaste, polyamides and the like. Formed. So it is, for example. in polyester fibers by polycondensation of terephthalic acid and ethylene glycol obtained synthetic fibers spun and drawn from the melt become.

The The present invention relates to a polycondensation process in the so-called "solid state phase", in which a polycondensation reactor already partly condensed or condensed raw granules, ie solid State of aggregation with a particle size of the order of magnitude supplied by a maximum of 2 mm and the granule raw material by energy supply in the reactor with elimination and removal of its remaining small molecule share going on in macromolecules implemented and the converted macromolecular granules of further processing supplied becomes.

So far is known here is the so-called precondensed raw granules out in a cooling bath jetted and strands or filaments fed to a suitable cutter, wherein This granulate is solid material particles with an outer dimension size, such as mentioned above, in the order of magnitude of a maximum of 2 mm, if possible but still much smaller, and with regard to a possible low penetration depth for the conversion energy supplied to each granule particle, the example. By accordingly hot Nitrogen and / or by appropriate external heating of the respective Condensation reactor is brought to the granule particles. so However, small granules require a correspondingly powerful cutter or a Granuliereinrichtung, or the discharge capacity of a continuously operating condensation reactor or the so-called Batch size is corresponding low.

outgoing of a polycondensation process of the type mentioned The invention is based on the object, this method to the effect to improve that at comparably equal in size Process apparatus a much larger discharge or throughput capacity and improved and more homogeneous through-condensation of the individual granule particles is reachable.

These Task is with a polycondensation of the aforementioned Art according to the invention achieved in that the condensed granulate raw material to threads or strands with the top and contact surfaces for the Increasing energy supply Cross-sectional structures spun or formed, this cooled threads or strands to granules be cut and the granules in this form in the reactor introduced and in which the polycondensation is subjected.

This Procedure can be, what's even closer explained is, both continuously and discontinuously in accordance with trained condensing reactors are carried out, wherein the such reactors of previous type serving for such postcondensation and basically nothing about their operation.

By correspondingly designed spinning or molding mouthpieces formed, cross-sectional structured strands or threads or filaments are indeed known, but these are, for example, for the immediate textile Further processing determined, but not from it for a post-condensation to form granules in the so-called solid state phase, there was no reason to so for the purpose of surface enlargement accordingly cross-sectional structured strands by cutting into granules.

Under the proviso "with the surfaces for the energy effect magnifying Cross-sectional structuring spun or formed "are all structurings to understand that, based on a specific particle mass volume and compared to a spherical, cubic or cylindrical surface, a have a much larger surface, what about exemplary embodiments will be explained in more detail.

In a sense, up the detour over the special surface design of the so-called raw granules is using the inventive method for one Optimal energy input into or on the individual granules (s) taken care of. The decisive improvement, namely up to 4 times increased throughput at gegf. thereby smaller measurable Plant components, so is not caused by a change in the achieved by known polycondensation, but by a structural change to be treated with this method, already condensed and granules in the solid aggragate state.

The inventive method will be described below with reference to the drawings of exemplary embodiments explained in more detail.

It shows schematically

1 the procedure;

2 on average, a continuous condensation reactor to be operated;

3 in section a discontinuously operated condensation reactor and

4A - 4D greatly enlarged embodiments of thread or strand cross-sections.

1 illustrates schematically the course of the polycondensation process, in which a polycondensation reactor 1 Granules G having a particle size of the order of a maximum of 2 mm supplied and the granule raw material of synthetic plastic by energy input in the reactor 1 is converted into macromolecules under elimination and removal of its small molecular weight fraction.

In 1 are also designated with 2 the corresponding strand forming mouthpieces having means for forming the strands, with 3 one to the cutter or strand pelletizer 4 leading cooling section and with 6 one with the condensation reactor 1 in Zuförderverbindung 7 standing granule silo, which is usually a granulate dryer 5 upstream. 1 In this respect, reference is made to a continuously operated condensation reactor 1 , which is also highly schematized and average in 2 is shown. Basically, the process scheme according to 1 also when discontinuous with a batch reactor according to 3 is working, in the granule silo 6 granules are fed to the batch reactor in each case as Füllcharge and in this batch polycondensed and is also taken as a batch.

For both cases, it is now essential that the condensed granulate raw material GR is formed into threads or strands FS with the surface areas for the energy action increasing cross-sectional structures, these cooled threads or strands FS are cut or granulated to granules G and this here called raw granules RG in this form in the reactor 1 introduced and is subjected in this polycondensation. The granulate brought to the desired degree of polycondensation is removed from the reactor according to 2 permanent and from the batch reactor according to 3 discharged as a charge and is designated PMG. On the presentation of all else necessary for such equipment accessories, such as valves, exhaust fans, control devices and the like. is omitted, especially since nothing changes at these facilities or facilities except for the Stausausformmundstücke for the Rohgranulatstränge FS. In that regard, it is due to in the 2 and 3 with specified resources, passage arrows, fill level information and the like. Also, no detailed explanations regarding what is going on in the reactors 1 . 1' takes place.

For batch operation comes, also known, especially one with external heating 8th provided for the power supply, rotatable or pivotally mounted batch reactor, such as in 3 shown for use. The in 2 illustrated flow reactor 1 can be advantageous and as shown also with such external heating 8th be provided.

In the 4A to 4D are, and extremely enlarged, illustrated embodiments of strand sections, dashed and perspective supplemented the respective overall shape of a granular particle is illustrated with. If one looks at this in a somewhat smaller size, for example, a cylindrical or cube-shaped and solid granules particles, it is clear that in the example. Granules shown in the reactor introduced into the granule reaction energy conversion reaches much cheaper and faster to the inner mass ranges ,

Claims (3)

Polycondensation process in which a polycondensation reactor Granules with a particle size in the Magnitude supplied by a maximum of 2 mm and the synthetic resin granular raw material by supplying energy in the reactor with elimination and removal of its small molecular weight fraction in macromolecules is reacted, characterized in that the condensed Granulatrohmaterial to threads or strands with the surfaces for the Enlarge the impact of energy Cross-sectional structures formed, these cooled threads or strands cut into granules and this raw granulate in this form in the Reactor introduced and in which the polycondensation is subjected. Method according to claim 1, characterized in that that this Process continuously in a continuously loadable and emptied Condensation reactor performed becomes. Method according to claim 1, characterized in that that this Process is carried out batchwise in a batch reactor.