Classifications

• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
  • D01F6/28—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from copolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D01F6/30—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from copolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds comprising olefins as the major constituent

Definitions

• the invention relates to a process for the preparation of fibres of a i linear polymer of alternating ethylene and carbon monoxide units, in
• the process now found comprises the following components: polyketone polymer of the proper intrinsic viscosity, a mediocre or even poor solvent in which the polymer takes up comparatively small hydrodyna ic volume, and a device for thoroughly intermixing the polymer and the solvent at a relatively high temperature and with forceful mechanical agitation.
• Hydrodynamic volume is defined as the product of the intrinsic viscosity of the polyketone polymer in a particular solvent at the processing temperature and the average molecular weight.
• these components are utilised such that: a homogeneous solution is formed in such a concentration as will have overlapping of the molecular chains, which overlapping is preserved after cooling to below the crystallisation temperature of the solution, the homogeneous solution is extruded, and the resulting extrudate rapidly gels as it is cooled on account of the formation of crystalline nuclei, causing a thermoreversible gel to be formed which is drawable to a draw ratio ( ⁇ ) of at least 6 and by being drawn to a draw ratio between 6 and 13 produces an oriented fibre with an initial modulus equal to or higher than 10/9* ⁇ -2,5 (N/tex).
• an oriented fibre with an initial modulus higher than 10/9- ⁇ -l,75 (N/tex) is obtained.
• the initial modulus is at least 10/9- ⁇ -l (N/tex), but will be less than 10/9- ⁇ +4 (N/tex).
• the optimal oriented fibre will have an initial modulus which at least fulfills the equation:
• a permanently orientable thermoreversible gel is formed if said gel is drawable to a draw ratio of at least 6 and if from said gel an oriented fibre can be obtained which has an initial modulus in the range of 10/9. ⁇ -2,5 (N/tex) to 10/9- ⁇ +4 (N/tex) for a draw ratio between 6 and 13.
• the solvents used are those which are generally considered to be so- called poor solvents for the polymer.
• the boiling point of these solvents is above 443 K, more particularly above 453 K, and in a most preferred embodiment above 477 K.
• These solvents will not dissolve the polymer in its entirety except with heating to a temperature above 443 K, preferably to above 453 K, and most preferably to above 477 K.
• the temperature at which there is virtually complete polymer dissolution lies below the boiling point of the solvent, so that the dissolving process can easily be carried out under atmospheric pressure.
• a suitable process for preparing a polymer solution lies in selecting a dissolving temperature equal to or higher than the boiling point of the solvent.
• Such a process may be carried out with advantage when, e.g., benzyl alcohol is used as solvent.
• benzyl alcohol At temperatures which do not exceed the boiling temperature by more than 5 K, operating under a pressure above 100 kPa will not be required in every case. At higher temperatures, however, this requirement will always be there.
• the dissolving temperature of polyketone in a particular solvent is defined as the temperature at which virtually complete dissolution of 5-10 wt.% of polyketone having an intrinsic viscosity of about 7 is observed in that particular solvent.
• the cohesion between the chains, and thus the gelling may be enhanced by so selecting the concentration of a polymer having a given intrinsic viscosity that the product of the polymer concentration and [ ⁇ ° > s is higher than 0,4 (dl/g)o»s. More favourable results still are attained if the product of the polymer concentration and [ ⁇ ° > s is higher than
• the intrinsic viscosity of the polyketone used generally is in the range of 0,5 to 10 dl/g but may be higher.
• Polyketone highly suited to be used in the process now found has an intrinsic viscosity in the range of 1,2 - 8 dl/g, in particular in the range of 1,2 - 4,5 dl/g.
• Very suitable polyketone for use in the present invention has an intrinsic viscosity in the range of 1,2 - 2,5 dl/g.
• Mw estimated molecular weight
• the polyketone polymer is primarily composed of alternating carbon monoxide and ethylene units according to the formula:
• this polymer may contain a small amount of other units, for instance propylene groups.
• other substances may be admixed, e.g., to improve the thermal and/or oxidative properties and/or other polymer and/or fibre properties.
• thermoreversible gel which can be permanently oriented without the solvent having to be removed if solvents are used of which the polymer dissolving temperature is lower than that mentioned in the claims. Using such solvents will result in thermoreversible gels which are far closer in character to gels prepared with a satisfactory solvent, which means, int. al., that the solvent cannot be removed from the obtained products without extraction, and the polymer concentration in the solutions obtained cannot be as high as presently found.
• the process now found has the significant advantage of the polymer being crystallised by cooling under normal spinning operation conditions, such as normal cooling speed, while the processes hitherto known always required that an extracting agent be employed to carry out the desired polymer crystallisation.
• the polymer is crystallised by cooling to room temperature under normal spinning conditions. Since the polymer is crystallised by cooling of the extrudate, it is possible to directly orient the molecular chains, e.g., by drawing the formed thermoreversible gel. Using the solvents according to the present invention in a great many cases renders solvent extraction with the aid of an extracting agent unnecessary.
• thermoreversible gel may be drawn directly on exiting from the extruder, optionally after first being passed, under low tension or virtually tensionless, along a source of heat.
• a preferred embodiment consequently is found in a process according to said invention in which at least 50% of the solvent is removed from the extruded product by a means other than extraction.
• the solvents to be employed according to the present invention have a melting point below 373 K. If the melting point is comparatively high, the solvent and polymer crystallisations will be subject to interference upon cooling. This brings about substantial deterioration of the mechanical properties of the fibres to be obtained. Accordingly, the melting point of an appropriate solvent according to the present invention will be less than 373 K, more particularly less than 318 K. The properties of the obtained fibres were found to have improved with the lowering of the solvent melting point.
• solvents are held to be suitable in particular because they have no or only very low toxicity and do not cause polymer degradation, and because the temperature at which the polymer dissolves is in a favourable range.
• solvents which contain at least one component from the group made up of: ethylene carbonate, propylene carbonate, benzyl alcohol, y- butyrolactone, e-caprolactam, dimethyl phthalate, and dipropylene glycol.
• the solvents to be used may be made up of one or more of the aforementioned components, but also contain other components. The important thing is that the mixture continues to satisfy the criteria for the solvent as given in the claims.
• solvents which are deemed suitable should be of low toxicity and/or cause little or no irritation, so that their handling does not call for any additional measures. For that reason, solvents containing a substantial amount of phenol are not suitable for use according to the present invention. Also, for economic reasons, the solvents should be comparatively inexpensive. In addition, they should be chemically inert with regard to the polymer. For instance, it was found that, at elevated temperature, benzoic acid and aniline break down the polyketone polymer. Furthermore, solutions prepared with the aid of the solvent will have to be reproducible in order to facilitate continuous spinning operations.
• the solution according to the present process may be prepared in the aforementioned concentration by intimate mixing of the solvent and the polymer with increasing temperature, followed by extrusion moulding of the solution.
• the preparation of the solution may take the form of feeding the polymer and the solvent to a kneading apparatus, and then using a spinning pump to press the mixture through an extrusion plate at elevated temperature.
• the temperature at which the solution is extruded preferably is above 453 K, but lower than the polymer degradation temperature.
• the polymer and the solvent may be mixed either in the kneading apparatus itself or intermixed in advance, with the resulting mixture, the suspension, subsequently being passed to the kneading apparatus.
• the solution is obtained by heating the mixture to or above the temperature at which the polymer dissolves.
• This temperature should be lower than the temperature at which there is substantial thermal decomposition of the polymer.
• a process suited to practical use is found by selecting the temperature lower than the solvent's boiling point at the prevailing operating pressure in the kneading apparatus, and higher than the polymer's dissolving point in the solvent at this operating pressure. More particularly, a temperature in the range of about 453 to 513 K is employed, depending on the solvent used.
• the polymer and the solvent are fed to a kneading apparatus equipped with one or more screws in order to subject the mixture to mixing and kneading at high mechanical shear rates.
• the kneading apparatus used is a twin-screw extruder, although also a single-screw extruder or another high shear kneader can very well be applied.
• the use of a twin-screw extruder is consider advantageous, since in such a mixing means the mixture is mixed and heated as well as transported.
• the construction of the screw is such as to give a short stay and low dispersion during that stay, which serves to counter polymer degradation and will benefit the constant quality of the solution to be obtained.
• the polymer's stay and temperature can be set in relation to the concentration and the solvent employed. For instance, it has been found that a stay in the range of about 1 to 5 minutes was very suitable for heating the mixture sufficiently for both dissolving and extruding purposes. Using such a twin-screw extruder makes it possible to obtain solutions with a very high polymer concentration. In addition, it is possible to operate under a pressure in excess of 100 kPa if so desired, without this giving any problems.
• the kneading extruder is connected to a spinning unit, and the resulting solution is fed directly to the spinning pump.
• the solvent can be removed by evaporation, e.g., by passing the solution through a heated tube, along a hotplate, or by a flow of hot air.
• the polymer will be crystallised by cooling. Cooling may take the form of air cooling, water cooling, water vapour cooling, passing over cooled rollers or through a bath containing a cooling liquid, or of a combination of cooling techniques.
• the extruded product may be drawn following its extrusion at elevated temperature or not, with the solvent being removed from the product either by the drawing process itself or by the heat applied during the drawing.
• Figure 1 shows the process according to a preferred embodiment of the present invention, which does without an extracting agent to remove the solvent.
• the polymer is charged and at (2) the solvent, whereupon both are heated in the twin-screw extruder (3) to the desired temperature, which will be above 443 K.
• (4) represents the spinning pump and (5) the filter through which the solution is pressed.
• the solution is pressed through the spinneret, referred to here as the extrusion plate (6), and the obtained extrudates are guided through a heated tube (7), after which, via a separator roll (8) and with the aid of a winder (9), the resulting fibres are wound onto a bobbin.
• the mechanical properties of the fibres are measured on filaments that have been conditioned at 21°C and 65% relative humidity for at least 16 hours.
• the breaking tenacity (BT), elongation at break (EAB), initial modulus (IM), and final modulus (FM) are obtained by breaking a single filament in a tensile tester.
• the gauge length for the filaments is 100 mm.
• the samples are elongated at a constant extension rate of 10 mm/min.
• the breaking tenacity and the elongation at break are obtained from the stress-strain curve as defined in ASTM D 2256-88.
• the initial and final moduli are obtained from the first derivative of the stress- strain curve (the modulus-strain curve) as the maximum moduli for a strain smaller than 0.2% and a strain larger than 2%, respectively.
• the linear density of the filaments (LD, expressed in dtex) is calculated on the basis of the functional resonance frequency as defined in ASTM D 1577-66, or by weighing of the filaments.
• N-methyl-2-pyrrolidone boiling point 475 K, melting temperature 249 K
• thermal analyses were carried out by repeatedly heating and cooling the contents of the closed vessel.
• the identically prepared solutions were found to have different temperatures for complete polymer dissolution. Heating the solutions a second time produced lower temperatures, which is indicative of polymer degradation.
• Solutions were prepared from polyketone having a molecular weight and an intrinsic viscosity [ ⁇ ] as listed in the table.
• the polyketone was composed of carbon monoxide and ethylene units and contained neither stabilisers nor any other additives.
• the polymer, in the powdered form was charged to a twin-screw extruder, where it was slowly heated to 353 K.
• 353 K the solvent was added, after which the mixture was dissolved by the kneading action of the extruder and the appropriate temperature settings to above the temperature at which the polymer dissolves.
• This temperature was 493 K for the propylene carbonate solutions, 458 K for benzyl alcohol, and 453 K for the propylene carbonate/resorcinol mixtures.
• the pellets made from solutions 1 and 8 in Example II were fed to a single-screw extruder with at its mouth a spinneret provided with a spinneret plate having 26 round orifices, each of 250 ⁇ m in diameter.
• the solutions were extruded and the formed extrudates crystallised by being cooled in air.
• the obtained solid filaments were washed out with water and subsequently drawn over a matt chromed pin heated at 509 K and two or three 34 cm long heated plates.
• the draw ratios of the spun fibres, the temperatures of the heated plates, and the mechanical properties found for the fibres are given in Tables II and III. 15
• LD linear density
• BT breaking tenacity
• EAB e ongation at reak
• IM initial modulus
• FM final modulus.
• the measured concentration of solution 1 was 0,34.
• the product of the concentration and [ ⁇ ] ° > ⁇ thus was 0,9435 (dl/g) 0 ' 5 .
• IM initial modulus
• FM final modulus
• the measured concentration of solution 8 was 0,29.
• the product of the concentration and [ ⁇ ] ° * - was 0,7 (dl/g)°» s .
• Example II The method as described in Example II was used to prepare fibres from Example II 's solution no. 9, except that this time the obtained filaments were not drawn over hotplates, but in a single step in a hot oven at a temperature of 498 K.
• the properties of the resulting products are listed in Table IV. TABLE IV
• LD linear density
• BT breaking tenacity
• EAB elongation at break
• IM initial modulus
• FM final modulus
• a solution of polyketone polymer and benzyl alcohol was prepared by charging powdered polyketone with an intrinsic viscosity of 2,93 and solvent to a twin-screw extruder.
• the temperature was 378 K in the first extruder zone and 453 K in the last one.
• the kneading action of the extruder and heating to 453 K caused the polymer to dissolve completely.
• the residence time of the polymer in the extruder was about 3 minutes.
• At the mouth of the extruder there was a spinneret with 10 orifices of 200 ⁇ m, through which the solution was passed.
• the temperature of the solution during the extrusion process was 458 K, the pressure applied was 7200 kPa.
• the fibres from this bobbin were not drawn over hotplates, but in one or two steps in a heated oven. At the end of the drawing set-up there was a bobbin onto which the formed fibres were wound.
• the measured polyketone concentration in the solution was 0,50.
• the product of the concentration and [rj]°» 5 was 0,86 (dl/g) 0 -* 5 .
• the drawing conditions and the mechanical properties of the resulting products are listed in Table V 17
• D inear ensity
• BT brea ing tenacity
• EAB e ongation at rea
• IM initial modulus
• FM final modulus
• the averaged value for 10 measurements is given.
• a mixture of fine solid polyketone powder with an intrinsic viscosity of 1,35 and propylene carbonate was prepared at room temperature using a Brabender blender.
• the blend having a total weight of approximately 15 grams, was homogenised for at least 15 minutes at a screw speed of 100 rpm.
• the resulting film was cut up into strands with a size of 0,08-0,1 mm (thickness) x 2 mm (width) x 30 mm (length). Some of the strands were washed with acetone before being drawn. The conditions for the preparation of the strands are listed in Table VI. The strands were drawn in a single step in a hot oven. The drawing conditions and the properties of the resulting products are listed in Table VII.
• BT breaking tenacity
• IM initial modulus
• FM final modulus
• the polyketone polymer was composed of carbon monoxide and ethylene units and contained neither stabilisers nor any other additives.
• the solution was prepared by heating the solvent and the polymer in a stirred beaker under nitrogen to 493 K. The time required for dissolution was 120 minutes.
• the formed solution was passed through six spinning orifices of a diameter of 300 ⁇ m each in a spinning machine at 483 K. 10 mm beneath the spinneret plate there was an extraction or coagulation bath filled with acetone of 250 K, through which the moulded extrudates were passed. Next, free of solvent, the fibres were drawn by being passed over one or more hotplates under tension, and wound.
• the solution was prepared by heating the solvent and the polymer to 493 K in a stirred closed dissolving vessel under nitrogen. The time required for dissolution was 60 minutes.
• the formed solution was passed through a single spinning orifice of a diameter of 500 in a spinning machine at 483 K. 10 mm beneath the spinneret plate there was an extraction or coagulation bath filled with acetone of 248 K, through which the formed extrudates were passed. Next, free of solvent, the fibres were drawn by being passed over one or more hotplates under tension, and wound.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Artificial Filaments (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Multicomponent Fibers (AREA)

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• 1994
  • 1994-01-07 AT AT94904651T patent/ATE167534T1/de not_active IP Right Cessation
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  • 1994-01-07 CN CN94190937A patent/CN1116435A/zh active Pending
  • 1994-01-07 WO PCT/EP1994/000061 patent/WO1994016127A1/en active IP Right Grant
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  • 1994-01-07 UA UA95073315A patent/UA42708C2/uk unknown
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