IL21830A - Wet extrusion of synthetic polymer solutions particularly for the obtainment of fibres - Google Patents

Description

The present invention relates to an in the processes and apparatus wet spinning of polymer particularly useful the spinning device does not have to be in coagulating The invention relates particularly to an improvement of a spinning apparatus vinyl polymer in the spinning device kept separate from the coagulating either because the temperature of the solution be higher than that of the coagulating or to prevent the material which forms the spinneret holder being attacked by the coagulating bath or for still other She term polymers vinyl as used in the presen specification covers both of vinyl chloride having syndlotacticity degree greater than 2 is the degree determined by the ratio for the absorption bands and see pages as as copolymers of the latter with other suitable and mixtures of PVC syadiotactic polyvinyl chloride with suitable polymers provided the of the vinyl chloride in such copolymers and mixtures is not lower than equipment usually employed in wet spinning of polymer solutions is formed of a spinning to suitable spinneret the whole being into the coagulating It is known that the dope to be spun is fd to innn dev b m f a suitabe type of spinning device is unsuitable when the spinning device be kept separate from the coagulating More particularly it is unsuitable for spinning of highly vinyl chloride polymer solutions when the coagulating bath must be maintained at a temperature lower than that of the for the following Solutions of highly syndiotaetic inyl chloride have a tendency to gel at fairly gh Shis gel temperature with the otereoregularity of the hence with the polymerisation temperature and the quantity of polymer present in the For an solution of polymer of a syndiotacticity degree of about and an intrinsic viscosity of abruptly gels at and a solution of the same polymer at On the other the best coagulant mixtures for spinning highly vinyl chloride polymers are rather volatile and aust therefore be at th rather low temperature of to avoid evaporation of the coagulant mixtures and consequent increased cost of the finished it been experimentally proved that also in cases in which non volatile have been c employed as coagulant the is and brighter and sore compact fibres are if the coagulation is carried out at temperatures lower than a standard spinning device with the s inneret comletel submered in coagulating bath not if it is operated at high temperature to avoid of the polymer solution there is a loss of the compounds constituting the coagulating bath by and on the other hand if it is operated at low temperature the dope gels because of the inevitable cooling in the feeding pipe to the spinning due to which spinning is rendered the invention consists in a process for obtaining fibre or other extruded articles in which solutions highly polymers of vinyl maintained a temperature are wet spun by into a eoagulating bath maintained at temperature between and in the spinning solution and coagulating bath in containers adjacent to one another but thermally isolated one another to an extent sufficient to the stated temperature difference invention further in a process as set out in which the wet spinning is effected in an apparatus comprising a vessel for holding the coagulating provided with an opening in its aide in which a neret is so when the vessel is only the spinneret face is in eontact with the coagulating the solvent used for the hi actic vinyl chloride is diaeth dlmethylacetaiaide or ethyl isopropyl tertiary butyl acetone or acetic acid are used as precipitant in the coagulating invention still further in an apparatus for the wet spinning of solutions highly syadiotaotic vinyl chloride comprising means for maintaining spinning solution at a temperature and a vessel holding the bath provided with an opening in its side in which a spinneret is so the vessel is only the spinneret is in contact with the whereby a difference is maintained between the spinning solution and the coagulating advantage in using above mentioned type of spinning device lies in the improved filterability of the solution due to the higher temperature It is possible to very thin filters without the spinneret holes clogging and thus the evenness and final characteristics of the obtained fibres invention will be more fully described with reference to the accompanying which shows a matic sectio through one embodiment of the and With reference to the the spinning solution comes from tank by means of general duct passes into e after filtering in the filter it goes to the spinning device ich is flanged or attached by some ensuring a good seal to the spinneret holder 5 directly coupled to tank which contains the coagulating The eontact between the spinning solution and the coagulating bath is limited to the external surface of the spinneret heating jacket in which hot oil may be metering pump filter 3 and spinning device allows the solution to be kept at the desired is provided at its lower part with a 12 allows the coagulating bath to be emptied every time cleaning or checking of the spinning device is filaments coming from the spinning are drawn out around roller 11 and subjected to appropriate When wit a normally used spinning a solution of polyvinyl chloride of high syndiotacticity degree in an organic solvent such as nitrobenzene and the and using as coagulating bath a mixture of the solvent and one or acre such as acids amides or the the spinning be interrupted after 10 minutes because of the clogging of the spinneret This clogging is due to gelling of the dope before i is On the other hand by employing a coagulating bath constituted by and a non volatile as o for instance acetic acid the bath at 1000 the fibres obtained are internally split and practically unsuitable for textile Furthermore a such a temperature high evaporation of the bath constituents takes place using the device of the and maintaining the temperature of the spinning solution between and and that of the coagulating bath between and in any case low enough as not to have the compounds of the bath itself eva oratin continuous running and insufficientOCRQuality

Claims (1)

described and ascertained the nature of our said invention and in what manner the same is to be declare that what we claim process obtaining fibre or other extruded articles in which solutions of highly syndiotactic polymers of vinyl chloride hereinbefore siaiatained at a between and are wet spun by extrusio into a coagulating bath maintained at a temperature in which the spinning solution and the coagulating bath are in containers adjacent to one another but are thermally isolated another to an extent sufficient to maintain the stated temperature difference between process as claimed in Claim which the wet spinning is effected in an apparatus coiaprising a vessel fo holding the coagulating bath provided with an in its side in which a spinneret is fixedj so that when the vessel is only the spinneret face is in contact with the coagulating process as claimed in
1. Claim 1 or in which the solvent used for highly vinyl chloride polymers is process as claimed in Claim f i which the coagulating bath comprises a mixture of the said water and one of the methyl alcohols isopropyl tertiary butyl acetone or acetic Apparatus for the spinning of solutions of syndiotactic polymers of vinyl comprising maintaining the spinning solution at a desired temperature a vessel for holding the coagulating hath provided with opening in its side in which a spinneret is so the vessel is only the spinneret face is in contact with the a temperature difference is laaintained between the spinning solution and the coagulating A process for obtaining fibre or other extruded articles solutions of highly syndiotactic vinyl chloride according to substantially as hereinbefore particularly described wit reference to and as illustrated in the accompanying Apparatus for the wet spinning of highly syndiotactic vinyl chloride polymer solutions according to Claim tially as hereinbefore particularly described with reference to and as illustrated in the accompanying fibre or other extruded articles obtained by the process as claimed in any one of Claims 1 to or Dated this 2nd day of Fo Applicants insufficientOCRQuality