Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G64/00—Macromolecular compounds obtained by reactions forming a carbonic ester link in the main chain of the macromolecule
  • C08G64/42—Chemical after-treatment

Definitions

• the present application relates to a process for the chemical-mechanical recycling of low molecular weight polycarbonate residues and production wastes.
• Polycarbonates e.g. from bisphenol A
• polycarbonates are mostly amorphous engineering thermoplastics with high-quality properties, such as high transparency, heat resistance and toughness.
• aromatic copolycarbonates which are composed, for example, of bisphenol A and a cobisphenol. The manufacturing costs of such materials and their level of properties therefore also justify more demanding recycling processes, if used moldings or
• 931 810 discloses a process for increasing the molecular weight of degraded low molecular weight polycondensates such as polyamides, polyesters and polycarbonates using reactive chain extenders. These chain extenders react in the plastic melt, e.g. on an extruder, under usual compounding conditions with the functional chain ends of the polymer.
• Chain extenders are called special bisepoxides or these in combination with u. a. Epoxides, bisoxazolines, dicyanates, tetracarboxylic acid dianhydrides, bismaleimides and carbodiimides. However, no example of how the process works with polycarbonate is given. The applicant's own experiments for polycarbonate showed no increase in molecular weight after the in
• the subject of DE-PS 43 26 906 is a process for the chemical recycling of polycarbonate by transesterification with hydroxy compounds, in particular phenol, until the bisphenol and the esterified carbonate unit are obtained and subsequent
• DE-OS 42 40 314 differs from the above patent essentially by an upstream degradation of the polycarbonate to oligomers, which is carried out by transesterification with low-boiling monophenols. Subsequently, the degradation product and, if appropriate, an addition of diaryl carbonate by recondensation with elimination of the monophenol are first of all more viscous
• Oligomer with a certain content of OH end groups is generated, which is then polycondensed in the last stage under more severe reaction conditions in the melt to the desired polycarbonate.
• the polycarbonate is first degraded, making an additional process step necessary.
• Another disadvantage is that oligomers with OH end groups are much more sensitive to thermal and oxidative stress than the corresponding polymers and quickly become discolored and damaged. The condensation process is therefore sensitive and must be checked in a complex manner in order to achieve a precise reaction procedure which minimizes such effects.
• DE-OS 44 21 701 finally discloses a process for the chemical recycling of polycarbonates by degradation with diaryl carbonates to oligomers. After their crystallization in a certain solvent, cleaning and drying, they become polycarbonate, optionally with the addition of bisphenols and one
• the present invention therefore relates to processes for the condensation of polycarbonate, characterized in that polycarbonates can be condensed in the melt, expediently with addition of bisphenols or oligocarbonates with OH end groups to accelerate the reaction, if appropriate using catalysts, polycarbonates being obtained be that have a higher molecular weight compared to the starting polycarbonate.
• the polycarbonate to be condensed preferably bisphenol A polycarbonate
• the polycarbonate to be condensed is transferred into the melt as granules or regrind from PC moldings by means of suitable machines, which is then condensed in a batch or continuously operated reactor device.
• Suitable ranges of the reaction parameters are, for example, 0.01 to 5 mbar, preferably 0.1 to 2 mbar, 250-350 ° C melt temperature, preferably 280-320 ° C and average residence times of 0.01 to 0.3 hours for screw or extruder machines as well as 0.2 to 4 hours for stirred tanks, kneaders and disc or basket reactors. In the case of disk or basket reactors, dwell times of 0.5 to 2 hours are preferred.
• pressure and temperature can be varied in a time program until the specified ranges and within the specified ranges are reached.
• Continuous processes are usually run constantly at the appropriate temperature and pressure conditions, whereby pressure and temperature profiles can be set over the length of the reactor.
• Preferred, particularly preferred or very particularly preferred are embodiments in which the parameters, definitions and explanations mentioned under preferred, particularly preferred or very particularly preferred are used.
• the polycarbonate used either already has an average concentration of phenolic end groups of over 100 ppm OH, preferably 100-1500 ppm, particularly preferably 400-1000 ppm, or this is in the melt by adding bisphenols, preferably bisphenol A, or oligocarbonates with OH end groups, specifically adjusted. When reacting in the melt to higher molecular weights, volatiles split off are removed via the vapors from the
• Reactor device derived.
• the resulting small quantities are removed from the process in a suitable manner, which considerably simplifies the process.
• the condensation can be carried out in suitable stirred kettles, screw or kneading apparatus, extruders, disk or basket reactors, and in combinations of such apparatus.
• extruders or basket or disk reactors are preferred, particularly preferably basket or disk reactors, as described in DE application no. 1 011 98 51 or DE -C2 44 47 422.
• Basket or disc reactors are also for a batch
• the condensation may have to be accelerated by adding a condensation catalyst.
• Suitable catalysts and their use concentrations can be found in the literature (Chemistry and Physics of Polycarbonates, Polymer Reviews, H. Schnell, Vol. 9, pages 44-51, John Wiley & Sons, 1964; DE-PS 1 031 512; EP-A 360 578; EP-A 351 168; US-A 3,442,854).
• Alkali or alkaline earth metal compounds with an alkaline action and ammonium or phosphonium salts are preferred, hereinafter referred to as onium salts.
• Phosphonium salts for the purposes of the invention are those of the formula (IV)
• R 1 "4 can be the same or different C 1 -C 10 alkyls, C 6 -C 10 aryls, C 7 -C 6 0 aralkyls or C 5 -C 6 cycloalkyls, preferably methyl or C 6 -C 1 - Aryls, particularly preferably methyl or phenyl, and X "can be an anion such as hydroxide, sulfate, hydrogen sulfate, hydrogen carbonate, carbonate, a halide, preferably chloride, or an alcoholate of the formula OR, where RC 6 -C 4 aryl or C 7 -C ⁇ 2 -
• Aralkyl preferably phenyl, can be.
• Preferred catalysts are tetraphenylphosphonium chloride, tetraphenylphosphonium hydroxide,
• Tetraphenylphosphonium phenolate particularly preferably tetraphenylphosphonium phenolate.
• alkaline compounds of alkali metals and alkaline earth metals such as hydroxides, alkoxides and aryloxides of lithium, sodium, potassium, magnesium and calcium, preferably of Sodium.
• alkaline earth metals such as hydroxides, alkoxides and aryloxides of lithium, sodium, potassium, magnesium and calcium, preferably of Sodium.
• Most preferred are sodium hydroxide and sodium phenolate, and the sodium bisphenolate of bisphenol A.
• the polycarbonate is preferably introduced into the condensation reactor via a screw as a melting unit. If bisphenols or
• the screw is also a mixing unit.
• a melt sieve with or without backwashing device can be positioned between the screw and the condensation reactor in order to retain particulate contaminants> 5 ⁇ m from the thin melt.
• the melt flowing out of the condensation reactor after the polycondensation is discharged by means of a gear pump.
• the melt can be passed through static mixers or extruders and mixed with additives and other additives to adjust special formulations of the polycarbonates produced, in order to then lead to the granulation.
• additives are e.g. in WO 99/55772, pp. 15-25, DE application no. 10122496.6 and in "Plastics Additives", R. Gumbleter and H. Müller, Hanser Publishers 1983.
• the additives can be added at any time during the reaction, preferably before the granulation.
• Any bisphenol or an oligocarbonate with OH end groups can optionally be added to the polycarbonate to be condensed.
• the bisphenol or the OH-containing oligocarbonate, which is the basis of the polycarbonate to be condensed, is preferably added.
• the dosage of the bisphenol or the oligocarbonate in the weight ratio to the polycarbonate used in the bisphenol is in the range from 0: 100 to 10: 100, preferably from 0.1: 100 to 5: 100, particularly preferably from 0.2: 100 to 1: 100, and in the case of the oligocarbonate in the range from 0: 100 to 50: 100, preferably from 0.5: 100 to
• diphenols are 4,4'-dihydroxybiphenyl, 2,2-bis (4-hydroxyphenyl) propane (bisphenol A) and 1,1-bis (p-hydroxyphenyl) -3,3,5-trimethylcyclohexane.
• the oligomers obtained from these bisphenols can also be used according to the invention.
• the polycarbonate used has an average molecular weight M w of 15,000 to 30,000, preferably 16,000 to 25,000, particularly preferably 17,000 to 22,000, determined by measuring the relative solution viscosity in dichloromethane, calibrated by light scattering.
• a PC recyclate particularly preferably a PC recyclate from compact discs, is preferably used.
• the polycarbonates and copolycarbonates used can originate from the known phase interface or melt transesterification process and can therefore contain different chain terminators. Suitable chain terminators are, for example, phenol, octylphenol, cumylphenol and t-butylphenol. Further typical chain terminators for polycarbonate can be found in WO-Al 01/05866, pp. 4-6. Mixtures of chain terminators can also occur, for example by mixing different polycarbonates. Polycarbonates from the melt transesterification process preferably have this
• Phenol of the diphenyl carbonate used for the production as a chain terminator.
• the polycarbonates can differ in terms of the average molecular weight, the bisphenol used and / or the chain terminator, branching agent etc. used.
• the polycarbonates may also contain chain branching agents. Usual chain branching can also be found in WO-Al 01/05866, pp. 8-9.
• Polycarbonates which are composed of the same bisphenol are preferred, particularly preferably of bisphenol A.
• polycarbonates obtainable by the process according to the invention can be processed in a customary manner on customary machines, for example on extruders or injection molding machines, to form any shaped articles, for example to give films or sheets.
• other polymers can also be mixed into the polycarbonates according to the invention, e.g. Polyolefins, polyurethanes, polyester, ABS and polystyrene. These substances are preferably added on conventional ones
• Aggregates for the finished polycarbonate can, however, depending on the requirements, also be carried out at a different stage in the manufacturing process.
• polycarbonates themselves obtainable by the process according to the invention are likewise the subject of the present application. They differ from
• Primary goods i.e. the well-known commercial goods, by the presence fluorescent centers that fluoresce when irradiated with UV light, such as black light.
• This optical effect can be used, for example, in sorting processes in material recycling for plastic detection or to distinguish between a recyclate and primary goods.
• auxiliaries and reinforcing materials can be added to the polycarbonates according to the invention.
• thermal and UV stabilizers flow aids, mold release agents, flame retardants, hydrolysis stabilizers, finely divided minerals, fibrous materials, e.g. Alkyl and aryl phosphites, phosphates, phosphines, low molecular weight carboxylic acid esters, halogen compounds, salts, chalk, quartz powder, glass and carbon fibers, pigments, dyes and their combinations.
• Such connections are e.g. in WO 99/55772, pp. 15-25, and in "Plastics Additives", R. Gumbleter and H. Müller, Hanser Publishers 1983.
• additives can e.g. be metered into the melting and discharge screw or also directly into the melting reactor, but the discharge unit is preferred.
• the polycarbonates produced according to the invention can be used in many mechanically demanding applications. They are therefore suitable for the production of moldings and extrudates of various types. Possible applications are
• Safety windows which are known to be required in many areas of buildings, vehicles and aircraft, and as shields for helmets, foils, in particular ski foils,
• Blown bodies for example 1 to 5 gallon water bottles, translucent plates, in particular multi-wall sheets, for example for
• Lighting systems optical data storage, traffic light housings or traffic signs,
• Threads and wires (see for example DE-AS 1 137 167 and DE-OS 1 785
• optical device parts in particular lenses for photo and film cameras (see for example DE-OS 2 701 173),
• Light transmission carriers in particular fiber optic cables (see for example
• Luminaires for example headlight lamps, as so-called “head-lamps”, scattered light panes or inner lenses, medical applications, for example oxygenators, dialyzers, Food applications such as bottles, dishes and chocolate molds,
• Sporting goods such as Slalom poles or ski shoe buckles, household items such as Kitchen sinks and letterbox housings, housings such as e.g. Electric distribution cabinets, housings for electric toothbrushes and hair dryer housings, - transparent washing machines - portholes with improved resistance to the washing solution, protective glasses, optical correction glasses,
• Chip boxes and chip carriers as well as other applications, such as Barn doors or animal cages.
• PC regrind from the stripping of compact discs according to the process described in EP-A 537 567 (pp. 1, 2, 5, 6) was, after predrying, in a circulating air dryer (2 h / 120 ° C) using a ZSK 25 twin-screw screw ( Werner &
• the condensation reactor was a drum with melt inlet and outlet at the ends and a vacuum connection in the gas space, in which a shaft with disks that immersed in the melt slowly rotated. The speed was 0.8 revolutions per minute; the mean residence time of the melt was about 180 minutes.
• the pain temperature was 300 ° C, the
• A CD recyclate, obtained by stripping the regrind from CD disks.
• B A + 0.25% by weight BPA, 310/300 ° C, 0.8 mbar, 180 min.
• PC regrind from the stripping of compact discs was also condensed on an extruder. It was a two-shaft screw ZSK 32 (Werner & Pfleiderer) of 1.4 m length with a 0.8 m long vacuum dome, starting at 0.4 m of the screw length. The melt condensation was also carried out here without the addition of a transesterification catalyst. The material was pre-dried in a circulating air dryer (2 h / 120 ° C) before being fed in via a dosing scale. The results are summarized in Table 3. Table 3: Condensation of compact disc recyclate after decoating on a twin-screw screw (ZSK 32, Werner & Pfleiderer)

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• Chemical & Material Sciences (AREA)
• General Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Separation, Recovery Or Treatment Of Waste Materials Containing Plastics (AREA)
• Polyesters Or Polycarbonates (AREA)
• Compositions Of Macromolecular Compounds (AREA)
• Processes Of Treating Macromolecular Substances (AREA)

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• 2001
  • 2001-08-31 DE DE10142735A patent/DE10142735A1/de not_active Withdrawn
• 2002
  • 2002-08-19 AT AT02751175T patent/ATE399813T1/de not_active IP Right Cessation
  • 2002-08-19 EP EP02751175A patent/EP1425337B1/de not_active Expired - Lifetime
  • 2002-08-19 KR KR10-2004-7002926A patent/KR20040032979A/ko not_active Abandoned
  • 2002-08-19 JP JP2003525070A patent/JP2005501949A/ja active Pending
  • 2002-08-19 DE DE50212450T patent/DE50212450D1/de not_active Expired - Fee Related
  • 2002-08-19 ES ES02751175T patent/ES2306773T3/es not_active Expired - Lifetime
  • 2002-08-19 WO PCT/EP2002/009237 patent/WO2003020805A1/de not_active Ceased
  • 2002-08-19 CN CNB028171195A patent/CN1279094C/zh not_active Expired - Fee Related
  • 2002-08-28 US US10/229,787 patent/US6887968B2/en not_active Expired - Fee Related
  • 2002-08-30 TW TW091119732A patent/TW593407B/zh not_active IP Right Cessation

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