DE10147712A1 - Process for the production of aliphatic polycarbonates - Google Patents

Abstract

The invention relates to a method for producing high−molecular aliphatic polycarbonates having the following properties: the average molecular weight <o>M</o>w ranges from 30,000 to 1,000,000, and; the content of cyclic carbonates and polyethers equals, in total, a maximum of 5 wt. %. Said polycarbonates are produced by polymerizing carbon dioxide with at least one epoxide while using at least one catalyst selected from the group consisting of zinc carboxylates and multi−metal cyanide compounds. The invention is characterized in that the catalyst is introduced in anhydrous form, and the catalyst is firstly brought into contact with at least a partial quantity of the carbon dioxide before the epoxide is added.

Description

• - das gewichtsmittlere Molekulargewicht M _w, bestimmt mittels Gelpermeationschromatographie unter Verwendung von Hexafluoroisopropanol als Eluent und Polymethylmethacrylat-Standards, beträgt 30.000 bis 1.000.000,
• - der Gehalt an cyclischen Carbonaten und an Polyethern beträgt zusammengenommen maximal 5 Gew.-%,

durch Polymerisation von Kohlendioxid mit mindestens einem Epoxid der allgemeinen Formel 1


worin die Reste R unabhängig voneinander für Wasserstoff, Halogen, -NO₂, -CN, -COOR oder eine Kohlenwasserstoffgruppe mit 1 bis 20 C-Atomen, die substituiert sein kann, stehen,
unter Verwendung mindestens eines Katalysators, ausgewählt aus der Gruppe bestehend aus Zinkcarboxylaten und Multimetallcyanidverbindungen. The invention relates to a process for the production of high molecular weight aliphatic polycarbonates with the following properties

• - the weight average molecular weight M _w , determined by means of gel permeation chromatography using hexafluoroisopropanol as eluent and polymethyl methacrylate standards, is 30,000 to 1,000,000,
• the content of cyclic carbonates and polyethers taken together is a maximum of 5% by weight,

by polymerizing carbon dioxide with at least one epoxide of the general formula 1


in which the radicals R independently of one another represent hydrogen, halogen, -NO ₂ , -CN, -COOR or a hydrocarbon group with 1 to 20 C atoms, which may be substituted,
using at least one catalyst selected from the group consisting of zinc carboxylates and multimetal cyanide compounds.

The invention also relates to aliphatic polycarbonates, available by this process, as well as thermoplastic Molding compositions containing these polycarbonates. Finally concerns the invention the use of these thermoplastic molding compositions for the production of molded parts, foils, films, coatings and fibers, as well as these molded parts, foils, films, coatings and fibers from the thermoplastic molding compositions.

Copolymers of epoxides such as ethylene oxide (abbreviated EO) or propylene oxide (abbreviated PO) and carbon dioxide (CO ₂ ) and processes for their production are known. The copolymers are referred to as aliphatic polycarbonates or aliphatic polyether carbonates.

Common catalysts for these polymerization reactions are in particular organic zinc compounds such. B. Zinc carboxylates, or cyanide complexes with two or more metal atoms, e.g. B. Double metal complexes.

DE-A 197 37 547 describes a process for the preparation of polyalkylene carbonates by means of a catalyst which is prepared from zinc oxide or other inorganic zinc compounds and a mixture of two aliphatic or aromatic dicarboxylic acids. First the epoxide and then CO _{2 are} metered into the reactor, ie the catalyst first comes into contact with the epoxide before CO _{2 is} added.

US Pat. No. 5,026,676 discloses a process for the copolymerization of CO ₂ and epoxides in the presence of zinc carboxylate catalysts, the epoxide and then the CO _{2 again being added} to the reactor.

US Pat. No. 4,943,677 describes a similar process in which the zinc carboxylate catalyst is placed in the reactor and heated in a nitrogen stream for several hours before the epoxide and then the CO _{2 are} added.

A corresponding method is disclosed in US Pat. No. 4,783,445, in which a zinc dicarboxylic acid ester is used as catalyst. Again, the epoxy is first added to the catalyst before CO _{2 is} injected.

US Pat. No. 5,041,469 describes the copolymerization of epoxide and CO ₂ in methylene chloride of the solvent, epoxy, CO ₂ and the zinc carboxylate catalyst being introduced together.

The three WO-A documents 01/04178, 01/04179 and 01/04183 describe a process for the preparation of polyoxyalkylenes from epoxides in the presence of metal cyanide complexes as a catalyst, it also being possible to use CO ₂ . The catalyst and epoxy are introduced and left to activate the catalyst. Then the reaction starts and further epoxy is added.

EP-A 222 453 discloses a process for the preparation of polycarbonates from epoxides and CO ₂ using a catalyst system consisting of double metal cyanide compounds and a cocatalyst such as zinc sulfate. The polymerization is initiated by bringing a small part of the epoxide into contact with the catalyst system. Only then the remaining amount of epoxy and the CO _{2 are} metered in simultaneously, the copolymerization taking place (p. 3, lines 53-57 and examples).

US Pat. No. 4,500,704 describes a process for the preparation of epoxy-CO ₂ copolymers in which double metal cyanide complexes are used as catalysts. Here, too, the double metal cyanide catalyst is first activated before the actual copolymerization by being brought into contact with the epoxy for up to 45 min. Only then is CO ₂ injected and copolymerized (column 5, lines 46-50). According to Example 1, the PO-CO ₂ copolymer obtained has a number average molecular weight (molar mass) M _n of 23,000.

• - Die Aktivität der Katalysatoren ist unzureichend, d. h. pro Gramm verwendetem Katalysator werden so wenige Gramm Polymer erzeugt, daß das Verfahren unwirtschaftlich ist.
• - Die Polymerisationszeiten sind mit vier bis 84 Stunden so lang, daß das Verfahren unwirtschaftlich ist.
• - Die Molekulargewichte der erhaltenen Polycarbonate sind so gering, daß ihre Gebrauchseigenschaften (insbesondere die mechanischen Eigenschaften) auf unakzeptabel niedrigem Niveau liegen. D. h. die Polycarbonate sind zur Herstellung von Formmassen bzw. Formteilen kaum geeignet.
• - Neben den gewünschten Polycarbonaten werden auch unerwünschte Nebenprodukte gebildet, insbesondere Epoxid-Homopolymere (also Polyether) und cyclische (meist monomere) Carbonate. Die Nebenprodukte verringern die Ausbeute an Polycarbonat und müssen ggf. aufwendig vom Hauptprodukt abgetrennt werden. Außerdem verschlechtern sie die mechanischen Eigenschaften des erhaltenen Polymergemisches erheblich. So erniedrigen cyclische Carbonate die Glasübergangstemperatur des Polycarbonats erheblich, was bestimmte Anwendungsmöglichkeiten vereitelt.

The methods of the prior art have at least one of the following disadvantages:

• - The activity of the catalysts is insufficient, that is, so few grams of polymer are produced per gram of catalyst used that the process is uneconomical.
• - The polymerization times are four to 84 hours so long that the process is uneconomical.
• - The molecular weights of the polycarbonates obtained are so low that their performance properties (in particular the mechanical properties) are at an unacceptably low level. I.e. the polycarbonates are hardly suitable for the production of molding compositions or molded parts.
• In addition to the desired polycarbonates, undesirable by-products are also formed, in particular epoxy homopolymers (i.e. polyethers) and cyclic (mostly monomeric) carbonates. The by-products reduce the yield of polycarbonate and may have to be separated from the main product at great expense. In addition, they significantly deteriorate the mechanical properties of the polymer mixture obtained. Cyclic carbonates, for example, significantly lower the glass transition temperature of the polycarbonate, which prevents certain possible uses.

The possible reaction products can be shown schematically using the example of the reaction of propylene oxide and CO ₂ as follows:

The indices n and k are integers greater than or equal to 1 and give the number of repetition units.

The polyethers III and the cyclic carbonates IV are unwanted by-products.

The polycarbonates I and the polyether carbonates II are the desired process products and are summarized here as "Polycarbonate" referred to. "Polycarbonates" in the sense of The invention accordingly includes both strictly alternating polycarbonates I as well as the polycarbonates II with polyether segments (Polyether).

The task was to remedy the disadvantages described. In particular, the task was to provide a process for the production of polycarbonates from epoxides and CO ₂ , in which the catalyst activity (polymer obtained per unit mass of catalyst) is improved.

There was also the task of using an economical process shorter polymerization times, especially times up to four Hours to provide.

In addition, the process should use higher polycarbonates Deliver molecular weight as the prior art methods. The Polycarbonates obtainable by the process should be better have mechanical properties.

Finally, a procedure should be found that uses less unwanted by-products arise. In particular, the Content of interfering polyether homopolymer III and in particular cyclic carbonates IV can be significantly reduced.

Accordingly, the process defined at the outset was found. It is characterized in that the catalyst in anhydrous Form uses, and that you first with at least the catalyst a portion of the carbon dioxide in contact before one inflicts the epoxy.

In addition, the aliphatic mentioned above Polycarbonates, thermoplastic molding compounds, the use of Molding compounds and the objects made from them found how mentioned at the beginning.

Preferred embodiments of the invention are See subclaims.

The weight average molecular weight M _w of the polycarbonates is determined by gel permeation chromatography (GPC, also known as Size Exclusion Chromatography (SEC)) using hexafluoroisopropanol (HFIP) as eluent and calibration with polymethyl methacrylate (PMMA) standards. You can work as follows, for example: Detector: ERC 7510 differential refractometer from ERC; Columns: HFiP Gel guard column and HFiP Gel linear separation column, both from Polymer Laboratories; Calibration with narrowly distributed PMMA standards with molecular weights M from 505 to 2,740,000 from PSS.

The polycarbonates produced by the process according to the invention have a weight-average molecular weight M _w from 30,000 to 1,000,000. Molecular weights are preferred M _w for propylene oxide as epoxy 200,000 to 500,000, and for ethylene oxide as epoxy 30,000 to 300,000.

The content of the polycarbonates in cyclic carbonates, e.g. B. cyclic carbonate monomers IV, and on polyethers, e.g. B. Polyether Homopolymers III (see diagram above) taken together a maximum of 5 wt .-%. I.e. the sum of the by-products cyclic carbonates and polyethers is a maximum of 5% by weight.

The content of cyclic carbonates and polyethers can be determined in a known manner. Nuclear magnetic resonance (NMR), in particular ¹ H-NMR, is usually used for this. A ¹ H-NMR spectrum of the process product polycarbonate indicates by appropriate bands (peaks) whether cyclic carbonates and / or polyethers are present in the polycarbonate. Their amount can be determined in a known manner by quantitative analysis of the spectra.

The following can be said about the process materials:
Carbon dioxide CO ₂ is inexpensive and part of the air and is available almost indefinitely.

The epoxides used have the general formula 1


on. The radicals R here independently of one another denote hydrogen, halogen, nitro group -NO ₂ , cyano group -CN, ester group -COOR or a hydrocarbon group with 1 to 20 C atoms, which can be substituted.

Such hydrocarbon groups are in particular C _1-20 alkyl, C _2-20 alkenyl, C ₃ -C ₂₀ cycloalkyl, C _6-18 aryl and C _7-20 arylalkyl. There can be two R groups if they are attached to different C atoms of the epoxy group


are bridged and thus form a C _3-20 cycloalkylene group.

The following groups are particularly suitable as substituents with which the C _1-20 hydrocarbon group can be substituted: halogen, cyano, nitro, thioalkyl, tert-amino, alkoxy, aryloxy, arylalkyloxy, carbonyldioxyalkyl, carbonyldioxyaryl, carbonyldioxyarylalkyl, alkoxycarbonyl, Aryloxycarbonyl, arylalkyloxycarbonyl, alkylcarbonyl, arylcarbonyl, arylalkylcarbonyl, alkylsulfinyl, arylsulfinyl, arylalkylsulfinyl, alkylsulfonyl, arylsulfonyl and arylalkylsulfonyl.

The epoxide used is preferably ethylene oxide, propylene oxide, Butylene oxide (1-butene oxide, BuO), cyclopentene oxide, cyclohexene oxide (CHO), cycloheptene oxide, 2,3-epoxypropylphenyl ether, Epichlorohydrin, epibromohydrin, i-butene oxide (IBO), or acrylic oxides. Ethylene oxide (EO), propylene oxide (PO), Butylene oxide, cyclopentene oxide, cyclohexene oxide or i-butene oxide. Very particularly preferably ethylene oxide and propylene oxide. It is understood that mixtures of the aforementioned epoxides can be used.

When using CO ₂ and two or more epoxies, polycarbonate terpolymers are formed. If you use e.g. B. In addition to CO _2, the epoxides ethylene oxide and cyclohexene oxide, CO ₂ / EO / cyclohexene oxide terpolymers are formed. Examples of suitable mixtures of two epoxides are: EO and PO (a CO ₂ / EO / PO terpolymer is formed), EO and cyclohexene oxide, PO and cyclohexene oxide, i-butene oxide and EO or PO, butylene oxide and EO or PO, etc.

The two or more epoxies can be mixed or separated be added from each other.

The CO ₂ : epoxy ratio can be varied within wide limits. Excess CO _{2 is} usually used, ie more than 1 mol CO ₂ per 1 mol epoxide.

The catalyst is selected from the group consisting of Zinc carboxylates and multimetal cyanide compounds.

Zinc carboxylates are zinc salts of carboxylic acids. Especially Suitable carboxylic acids are dicarboxylic acids, especially aliphatic ones Dicarboxylic acids. Adipic acid and Glutaric. Accordingly, zinc adipate and zinc glutarate very particularly suitable zinc carboxylates.

The zinc carboxylates are made in a manner known per se Zinc compounds (inorganic such as zinc oxide, zinc hydroxide, Zinc halide, or organic such. B. zinc acetate, zinc propionate) and the carboxylic acids corresponding to the carboxylate residue manufactured. Instead of the carboxylic acids you can also Carboxylic acid derivatives such as. B. carboxylic anhydrides or lower Use carboxylic acid esters such as acetates or propionates. Appropriate Manufacturing processes for zinc carboxylates are e.g. B. in the scriptures US-A 4 783 445 and DE-A 197 37 547.

Multimetal cyanide compounds are complexes per unit formula at least two metals complexly coordinated with cyanide ions, and possibly further ligands. At exactly two with cyanide coordinated metals per formula unit is also called Double metal cyanide complexes (DMC).

Suitable multimetal cyanide compounds are known and in described the following A documents: US 3,278,457, US 3,278,458, US 3,278,459, US 3,427,256, US 3,427,334, US 3,404,109, US 3,829,505, US 3,941,849, EP 283,148, EP 385,619, EP 654,302, EP 659,798, EP 665,254, EP 743,093, EP 755,716, US 4,843,054, US 4,877,906, US 5,158,922, US 5,426,081, US 5,470,813, US 5,482,908, US 5,498,583, US 5,523,386, US 5,525,565, US 5,545,601, JP 7,308,583, JP 6,248,068, JP 4,351,632 and US 5,545,601.

Multimetal cyanide complexes are also e.g. B. in the scriptures DD-A 148 957, EP-A 862 947, EP-A 654 302, EP-A 700 949, WO-A 97/40086, WO-A 98/16310, EP-A 222 453, EP-A 90 444, EP-A 90 445, WO-A 01/04177, WO-A 01/04181, WO-A 01/04182, WO-A 01/03830, DE-A 199 53 546 described.

Particularly suitable multimetal cyanide catalysts are double metal cyanide compounds, in particular those of the formula 2

M ¹ _a [M ² (CN) _b A _c ] _d .fM ¹ _g X _n .hH ₂ O.eL.kP (2)

The letters M, A, X, L and P stand for atoms or groups of atoms. CN and H ₂ O are cyanide and water. The superscript indices 1 and 2 are used to differentiate the different M. The subscript indices _{a, b, c, a, g, n} are stoichiometric indices and the letters f, h, e and k are mole numbers.

In the general formula 2 mean
M ¹ at least one metal ion selected from the group comprising Zn ²⁺ , Fe ²⁺ , Fe ³⁺ , Co ²⁺ , Co ³⁺ , Ni ²⁺ , Mn ²⁺ , Sn ²⁺ , Pb ²⁺ , Mo ⁴⁺ , Mo ⁶⁺ , Al ³⁺ , V ⁴⁺ , V ⁵⁺ , Sr ²⁺ , W ⁴⁺ , W ⁶⁺ , Cr ²⁺ , Cr ³⁺ , Cd ²⁺ , La ³⁺ , Ce ³⁺ , Ce ⁴⁺ , Eu ³⁺ , Mg ²⁺ , Ti ³⁺ , Ti ⁴⁺ , Ag ⁺ , Rh ²⁺ , Ru ²⁺ , Ru ³⁺ ,
M ² at least one metal ion selected from the group comprising Fe ²⁺ , Fe ³⁺ , Co ²⁺ , Co ³⁺ , Mn ²⁺ , Mn ³⁺ , V ⁴⁺ , V ⁵⁺ , Cr ²⁺ , Cr ³⁺ , Rh ³⁺ , Ru ²⁺ , Ir ³⁺ ,
where M ¹ and M ^{2 can be the} same or different,
A at least one anion selected from the group consisting of halide, hydroxide, sulfate, hydrogen sulfate, carbonate, hydrogen carbonate, cyanide, thiocyanate, isocyanate, cyanate, carboxylate, oxalate, nitrate, nitrosyl, phosphate, dihydrogen phosphate, hydrogen phosphate,
X at least one anion selected from the group comprising halide, hydroxide, sulfate, carbonate, hydrogen carbonate, cyanide, thiocyanate, isocyanate, cyanate, carboxylate, oxalate, nitrate,
where A and X can be the same or different,
L at least one water-miscible ligand selected from the group consisting of alcohols, aldehydes, ketones, ethers, polyethers, esters, polyesters, polycarbonates, ureas, amides, nitriles, sulfides, amines, ligands with pyridine nitrogen, phosphides, phosphites, phosphines , Phosphonates, phosphates,
P at least one organic additive selected from the group comprising polyethers, polyesters, polycarbonates, polyalkylene glycol sorbitan esters, polyalkylene glycol glycidyl ethers, polyacrylamide, poly (acrylamide-co-acrylic acid), polyacrylic acid, poly (acrylamide-co-maleic acid), polyacrylonitrile, polyalkylacrylates, polyalkyl methacrylates, polyvinyl , Polyvinyl ethyl ether, polyvinyl acetate, polyvinyl alcohol, poly-N-vinylpyrrolidone, poly (N-vinylpyrrolodone-co-acrylic acid), polyvinyl methyl ketone, poly (4-vinylphenol), poly (acrylic acid-co-styrene), oxazoline polymers, polyalkyleneimines, maleic acid, maleic anhydride copolymer, Hydroxyethyl cellulose, polyacetets, ionic surface-active and surface-active compounds, bile acid and the salts, esters and amides of bile acid, carboxylic acid esters, polyhydric alcohols, glycosides,
where a, b, d, g and n are whole or fractional numbers greater than zero, and
where c, f, h, e and k are whole or fractional numbers greater than or equal to zero, and
where a, b, c, d, g and n are chosen so that the electroneutrality of the cyanide compound M ¹ [M ² (CN) A] or the compound M ¹ X is ensured.

Formate, acetate and propionate are carboxylate groups A and X, respectively prefers.

The multimetal cyanide compounds can be crystalline or amorphous his. For k equals zero, the multimetal cyanide compounds are in usually crystalline or predominantly crystalline. Larger for k They are usually crystalline, semi-crystalline or in zero essentially amorphous.

The primary particles of the multimetal cyanide compounds point preferably a crystalline structure and a content of flaky particles of more than 30 wt .-%, based on the total weight of the multimetal cyanide compound. The Platelet shape of the particles leads to the proportion of catalytic active surface, based on the total surface, increases and thus the mass-specific activity increases.

The term "primary particle" refers to the individual crystallite understood how he z. B. on the Scanning electron micrographs can be seen. These primary particles can then become Store agglomerates, the so-called secondary particles.

The term "platelet-shaped" means that the The length and width of the primary particles are at least three times larger than the thickness of these particles.

The term "crystalline structure" is understood to mean that not just a short-range order in the solid state, such as one Arrangement of z. B. 6 carbon atoms around a metal atom, but also a long-range order exists, d. H. one can recurring unit, also called unit cell, define from which the entire solid can be built. If a solid is crystalline, this is expressed, among other things in the X-ray diffractogram. You can see in the X-ray diffractogram in the case of a crystalline substance, "sharp" reflections, the Intensities clearly, d. H. at least three times larger than that of the underground.

Instead of platelet-shaped, the primary particles can also, for. B. rod-shaped, cube-shaped or spherical.

• - als M¹ mindestens ein Metallion, ausgewählt aus der Gruppe enthaltend Zn²⁺, Fe²⁺, Fe³⁺,
• - als M² mindestens ein Metallion, ausgewählt aus der Gruppe enthaltend Co²⁺, Fe²⁺, Fe³⁺,
• - als A Cyanidanion,
• - als X mindestens ein Anion, ausgewählt aus der Gruppe enthaltend Formiat, Acetat, Propionat,
• - als L mindestens einen mit Wasser mischbaren Liganden, ausgewählt aus der Gruppe enthaltend tert-Butanol, Monoethylenglykoldimethylether (Glyme)
• - als P Polyether.

Preferred multimetal cyanide compounds contain:

• as M ¹ at least one metal ion selected from the group comprising Zn ²⁺ , Fe ²⁺ , Fe ³⁺ ,
• as M ² at least one metal ion selected from the group comprising Co ²⁺ , Fe ²⁺ , Fe ³⁺ ,
• - as A cyanide anion,
• as X at least one anion selected from the group comprising formate, acetate, propionate,
• as L at least one water-miscible ligand selected from the group comprising tert-butanol, monoethylene glycol dimethyl ether (glyme)
• - as P polyether.

Multimetal cyanide compounds of the above are particularly preferred Formula 2, where k and e are greater than zero. These connections contain the multimetal cyanide, at least one ligand L and at least one organic additive P.

Multimetal cyanide compounds are also particularly preferred Formula 2 above, where k is zero and optionally e is zero. These compounds do not contain any organic Additive P and optionally no ligand L.

Multimetal cyanide compounds with k are very particularly preferred and e is zero, where X is selected from the group containing formate, acetate and propionate. These connections contain no organic additive P and no ligand L. Details can be found in WO-A 99/16775. At this Embodiment are crystalline double metal cyanide catalysts prefers; and double metal cyanide catalysts, which are crystalline and are platelet-shaped (see WO-A 00/74845).

Also particularly preferred are multimetal cyanide compounds of the formula 2 in which f, e and k are not equal to zero. I.e. these compounds contain the metal salt M ¹ _g X _n , a ligand L and organic additives P. See WO-A 98/06312.

The preparation of the multimetal cyanide compounds is e.g. B. described in WO-A 00/74843, WO-A 00/74844, WO-A 00/74845, EP-A 862 947, WO-A 99/16775, WO-A 98/06312 and US-A 5 158 922. An aqueous solution of the metal salt M ¹ _g X _{n is} usually combined with an aqueous solution of the cyanometalate H _a M ² (CN) _b A _c , where H is hydrogen, alkali metal, alkaline earth metal or ammonium. The metal salt solution and / or the cyanometalate solution can contain the water-miscible ligand L and / or the organic additive P. After the solutions have been combined, ligand L and / or additive P may be added. When preparing the catalyst, it is advantageous to stir vigorously, e.g. B. with high-speed stirrer. The precipitate is separated off in a conventional manner and, if necessary, dried.

The starting material cyanometalate H _a M ² (CN) _b A _c with H equal to hydrogen (so-called cyanometalate hydrogen acids) can be used, for. B. on acidic ion exchangers from the corresponding alkali or alkaline earth metal cyanate, see z. B. WO-A 99/16775.

As in the older, unpublished DE application Az. 100 09 568.2, you can also start with an inactive one Prepare the catalyst phase and then through Convert recrystallization to an active phase.

Further details of the manufacturing process of the Those skilled in the art will find multimetal cyanide compounds in the writings of the three paragraphs above.

A compound which can be obtained by reacting aqueous hexacyanocobaltoic acid H ₃ [Co (CN) ₆ ] with aqueous zinc acetate solution is very particularly preferably used as the multimetal cyanide compound. This reaction can be carried out, for example, under the conditions given in the examples, see e.g. B. the local manufacturing specification.

For the process according to the invention for the production of high molecular weight aliphatic polycarbonates by polymerizing CO ₂ with at least one epoxide, the following is to be sawn (the reaction conditions mentioned below apply in the same way to zinc carboxylate and multimetal cyanide catalysts, unless stated otherwise):
According to the invention, the catalyst is used in anhydrous form. This means that the catalyst - apart from the chemically bound water (for example h mol crystal water in the general formula 2 above) - contains no water or only insignificant traces of water, in particular no water which adheres to the surface or is physically enclosed in cavities.

In a preferred embodiment, therefore, one does the Anhydrous catalyst before use. Particularly preferred this is done by looking at the catalyst before starting Polymerization in an inert gas stream or in a vacuum until water-free heated. Usually nitrogen, argon is used as the inert gas or other common inert gases.

The temperature up to which the catalyst is heated is usually 80 to 130 ° C. The duration of the heating is usually 20 to 300 min. Typical values are 2 hours at 120 ° C for zinc carboxylate and 4 hours at 130 ° C for Multimetal catalysts.

You can z. B. in the polymerization reactor present, make anhydrous in the inert gas stream (bake out) and - if necessary after cooling - carry out the polymerization in the same reactor, d. H. can make the catalyst anhydrous and polymerization easily done in the same vessel.

However, the catalyst can also be heated by vacuum or make other suitable drying methods anhydrous.

In a preferred embodiment, the anhydrous Thereafter, the catalyst is dissolved in an inert reaction medium or dispersed (suspended or emulsified) before the polymerization is started. The dissolving or dispersing can be carried out with stirring respectively.

All substances which are suitable as inert reaction medium are Do not negatively affect catalyst activity, especially aromatic hydrocarbons such as toluene, xylenes, benzene, also aliphatic hydrocarbons such as hexane, cyclohexane, and halogenated hydrocarbons such as dichloromethane, chloroform, Isobutyl. Ethers such as diethyl ether are also suitable further tetrahydrofuran, diethylene glycol dimethyl ether (Diglyme), dioxane, and nitro compounds such as nitromethane. Prefers toluene is used.

The inert medium can be pressed into the polymerization reactor, for example as such or preferably with a gas stream, it being possible to use an inert gas such as nitrogen or the reactant CO ₂ as the gas.

The catalyst is preferably first placed in the reactor, makes it anhydrous by heating it in an inert gas stream, cool and presses the inert reaction medium with stirring Gas into the reactor.

Based on the catalyst solution or dispersion (sum of The catalyst and reaction medium) Catalyst concentration preferably 0.01 to 20, in particular 0.1 to 10 wt .-%. Based on the sum of epoxy and inert reaction medium the catalyst concentration is preferably 0.01 to 10, particularly preferably 0.1 to 1% by weight.

In another, also preferred embodiment, works one without an inert reaction medium.

According to the invention, the catalyst is first brought into contact with at least a portion of the CO ₂ before the epoxide is added. Here, “with at least a partial amount” means that, before adding the epoxy, either a partial amount of the total amount of CO _{2 used is} added, or the total amount of CO _{2 is} already added.

Preferably, only a subset of the CO _{2 is added} , and this subset is particularly preferably 20 to 80, in particular 55 to 65,% by weight of the total CO ₂ amount.

Usually, adds the CO ₂ as a gas and the amount of CO ₂ is - set via the CO ₂ gas pressure - depending on the temperature. At room temperature (23 ° C) in the reactor, the CO ₂ pressure before the addition of the epoxide (hereinafter referred to as CO ₂ pre-pressure), which corresponds to the preferred partial amount of CO ₂ , is 5 to 70, in particular 10, when using the zinc carboxylate catalysts up to 30 bar, and when using the multimetal cyanide catalysts 5 to 70, in particular 10 to 50 bar. Typical values for the CO ₂ admission pressure are 15 bar for zinc carboxylate catalysts and 50 bar for multimetal cyanide catalysts, each at 23 ° C.

All pressure specifications are absolute prints. The CO ₂ admission pressure can be set discontinuously in one step or divided into several steps, or can be set continuously over a certain period of time linearly or following a linear exponential or stepwise gradient.

When choosing the CO ₂ admission pressure, the pressure increase in the reactor due to the subsequent heating of the reactor to the reactor temperature must be taken into account. The CO ₂ admission pressure (e.g. at 23 ° C) should be selected so that the desired CO _{2 end} pressure at the reaction temperature (e.g. 80 ° C) is not exceeded.

The catalyst is generally brought into contact with CO ₂ at temperatures of 20 to 80 ° C., preferably 20 to 40 ° C. It is particularly preferred to work at room temperature (23 ° C.). The duration of the contacting of catalyst and CO ₂ depends on the reactor volume and is usually 30 seconds to 120 minutes.

As a rule, the catalyst or the solution or dispersion of the catalyst is stirred in the inert reaction medium while being brought into contact with the CO ₂ .

Only after the catalyst has been brought into contact with CO ₂ is the epoxide added to the reactor. The epoxy is usually pressed as such or preferably with a small amount of inert gas or CO ₂ into the reactor.

The epoxide is usually added with stirring and can all at once (especially with a small reactor volume) or continuously over a period of generally 1 to 100 min, preferably 10 to 40 minutes, the addition taking place over time can be constant, or can follow a gradient that z. B. be ascending or descending, linear, exponential or gradual can.

The temperature when the epoxide is added is generally 20 to 100, preferably 20 to 70 ° C. In particular, you can a) either add the epoxy at low temperature (e.g. room temperature 23 ° C) and then adjust the reactor to the reaction temperature T _R (e.g. 80 ° C) or b) conversely, first set the reactor to Set the reaction temperature T _R and then add the epoxy. Variant a) is preferred.

The reactor is accordingly brought to the reaction temperature T _R before or - preferably - after the addition of the epoxide. The reaction temperature is usually set at 30 to 180, in particular 50 to 130 ° C. This is usually done by heating the reactor with stirring. The reaction temperature is usually 40 to 120, preferably 60 to 90 ° C. Typical values are 80 ° C for zinc carboxylate and 65 to 80 ° C for multimetal cyanide catalysts.

After reaching the reaction temperature are added, preferably with stirring, the residual quantity of CO ₂ in the reactor not provided when contacting the catalyst with CO ₂ already CO ₂ -Gesamtmenge was supplied (see above). Usually prepared the amount of CO ₂ again via the CO ₂ gas pressure one. CO ₂ is preferably added until the CO ₂ pressure (hereinafter referred to as CO _{2 end} pressure) is 1 to 200, preferably 10 to 100 bar when using zinc carboxylate catalysts and 20 to 200, preferably 80 to, when using multimetal cyanide catalysts 100 bar. Typical values for the final CO ₂ pressure are 20 to 100 bar for zinc carboxylate and 100 bar for multimetal cyanide catalysts.

All pressure specifications are absolute prints. The amount of CO ₂ added in this process step (final CO ₂ pressure) naturally also depends on the partial amount of CO ₂ that had previously been added. From the CO ₂ pressures and reaction temperatures mentioned it follows that the CO ₂ can be present in the reactor in the supercritical state (ie liquid). The CO _{2 is} in the supercritical state, particularly at CO _{2 end} pressures above 74 bar and reaction temperatures T _R above 31 ° C. In contrast to conventional chemical reactions in critical CO ₂ , the CO ₂ in the present process is not only a reaction medium, but also a feedstock (reaction partner) and reaction medium.

The final CO ₂ pressure can be set discontinuously at once or continuously as described for the CO ₂ upstream pressure.

After the final CO ₂ pressure has been reached, this can be maintained by replenishing the used CO ₂ , if necessary. If no CO _{2 is} replenished, the CO ₂ pressure generally drops during the reaction due to the consumption of CO ₂ . This is also possible.

Usually the time to complete the Polymerization reaction 60 to 500 min, preferably 120 to 300 min. On typical value for this post-reaction time is 3 to 4 hours. The reaction temperature is usually kept constant; however, you can also raise or lower them depending on the progress the reaction.

The proportions of CO ₂ : epoxy used in the process depend in a known manner on the desired properties of the polymer. The quantitative ratio (weight ratio) of total amount of CO ₂ : total amount of epoxy is 1: 1 to 2: 1.

In a preferred embodiment, all of the aforementioned process steps are carried out with the exclusion of water: not only the catalyst, but also the inert reaction medium, the CO ₂ and the epoxide are anhydrous or are rendered anhydrous in the customary manner.

After the polymerization reaction has subsided, the process is carried out Reactor contents on the polycarbonate. This happens in known way. As a rule, the reactor is left under stirring cool down, balances the pressure with the environment (venting the Reactor) and the polycarbonate polymer precipitates by the Reactor contents in a suitable precipitation medium.

Usually alcohols such as methanol are used as precipitation medium, Ethanol, propanol, or ketones such as acetone. Is methanol prefers. It is advantageous to use hydrochloric acid or a acidify other suitable acid to pH 0 to 5.5.

The precipitated polymer can be separated as usual, e.g. B. by filtration, and dried in vacuo.

In some cases, part of the reaction product is found Polycarbonate also dissolved or dispersed in the precipitation medium, for example in acidified methanol. This polycarbonate can isolated in the usual way by removing the precipitant become. For example, the methanol can be used under reduced pressure distill off, for example on a rotary evaporator.

• 1. Wasserfrei machen des Katalysators
• 2. Vorlegen des wasserfreien Katalysators in einen Polymerisationsreaktor
• 3. Optional Zufügen eines inerten Reaktionsmediums
• 4. Zufügen von Kohlendioxid
• 5. Zufügen des Epoxids
• 6. Erwärmen des Reaktors auf die Reaktionstemperatur
• 7. Optional zufügen von weiterem Kohlendioxid
• 8. Nach Abklingen der Polymerisationsreaktion Aufarbeiten des Reaktorinhaltes auf das Polycarbonat,

wobei die Schritte 5 und 6 vertauscht sein können (erst Erwärmen, dann Epoxid-Zugabe). From the above description of the method according to the invention, a preferred method results which essentially comprises the following method steps:

• 1. Make the catalyst anhydrous
• 2. Placing the anhydrous catalyst in a polymerization reactor
• 3. Optional addition of an inert reaction medium
• 4. Add carbon dioxide
• 5. Add the epoxy
• 6. Warm the reactor to the reaction temperature
• 7. Optionally add more carbon dioxide
• 8. After the polymerization reaction has subsided, work up the reactor contents onto the polycarbonate,

Steps 5 and 6 can be interchanged (first heating, then adding epoxy).

As already mentioned, the catalyst can be heated make anhydrous under inert gas in the reactor, thereby completing the steps 1 and 2 coincide.

• a) Die benötigten Katalysatormengen sind deutlich geringer, d. h. pro Gramm Katalysator werden mehr Gramm Polymer erzeugt. Dies erhöht die Wirtschaftlichkeit des Verfahrens.
• b) Die Polymerisationszeit ist mit 1 bis 10 insbesondere 2 bis 5 Stunden, typischerweise etwa 3 bis 4 Stunden erheblich kürzer, was die Wirtschaftlichkeit des Verfahrens stark verbessert.
• c) Die gewichtsmittleren Molekulargewichte M _w der erhaltenen Polycarbonate sind mit 30.000 bis 1.000.000 deutlich höher als nach dem Stand der Technik. Aus Polycarbonaten mit diesen Molekulargewichten lassen sich Formmassen bzw. Formteile, Folien, Filme und Fasern mit guten Gebrauchseigenschaften, insbesondere guten mechanischen Eigenschaften, herstellen.
• d) Durch Wahl geeigneter Reaktionsbedingungen lässt sich die Polymerisationsreaktion so steuern, daß kaum oder sogar gar keine unerwünschten Nebenprodukte entstehen. Insbesondere wird die Entstehung der störenden Polyether-Homopolymere (III im eingangs angegebenen Reaktionsschema) und der störenden cyclischen Carbonate IV deutlich vermindert oder unterbleibt ganz. Die verminderten bzw. fehlenden Nebenprodukte III und IV erhöhen die Ausbeute an Polycarbonat und verbessern so die Wirtschaftlichkeit des Verfahrens. Das Fehlen der Nebenprodukte erspart außerdem eine aufwendige Abtrennung vom Hauptprodukt. Dies verbessert die Wirtschaftlichkeit erheblich.
• e) Weiterhin verbessern sich durch den geringen bzw. nicht nachweisbaren Gehalt an störenden Nebenprodukten die mechanischen und andere Eigenschaften der Polycarbonate und der daraus hergestellten Formteile.

The method according to the invention has the following advantages over the methods of the prior art:

• a) The amounts of catalyst required are significantly lower, ie more grams of polymer are produced per gram of catalyst. This increases the economics of the process.
• b) The polymerization time is 1 to 10, in particular 2 to 5 hours, typically about 3 to 4 hours, considerably shorter, which greatly improves the economy of the process.
• c) The weight average molecular weights M _{w of} the polycarbonates obtained are significantly higher at 30,000 to 1,000,000 than according to the prior art. Polycarbonates with these molecular weights can be used to produce molding compositions or moldings, films, films and fibers with good performance properties, in particular good mechanical properties.
• d) By choosing suitable reaction conditions, the polymerization reaction can be controlled in such a way that little or no undesired by-products arise. In particular, the formation of the interfering polyether homopolymers (III in the reaction scheme given at the outset) and the interfering cyclic carbonates IV is significantly reduced or completely avoided. The reduced or missing by-products III and IV increase the yield of polycarbonate and thus improve the economy of the process. The lack of by-products also saves time-consuming separation from the main product. This significantly improves economy.
• e) Furthermore, the mechanical and other properties of the polycarbonates and the moldings produced therefrom improve due to the low or undetectable content of disruptive by-products.

In particular, with the method according to the invention Manufacture polycarbonates that have no or only insignificant amounts cyclic carbonates and no or only insignificant amounts Contain polyether.

By choosing suitable reaction conditions, Process product polycarbonate the ratio of alternating Adjust polycarbonate I to polyether carbonate II. The after Polycarbonates obtainable according to the invention have in a preferred embodiment at least 50, preferred at least 70, especially 75 to 95% carbonate linkages in the Polymer chain.

A high proportion of carbonate linkages means a low one Proportion of polyether segments in the polymer chain. pure alternating polycarbonate I has 100% carbonate linkages. A high one Share of carbonate linkages in the process product means accordingly, that the process product of the alternating polycarbonate I comes close. If the proportion of carbonate linkages is lower, then the process product comes close to polyether carbonate II.

The reaction conditions which control the polymerization reaction with regard to the ratio of main products I and II / by-products III and IV, and in particular with regard to the proportion of carbonate linkages in main product I and II and thus the (mechanical and other) properties, include in particular the catalyst, but also the amount of epoxy and CO ₂ , the CO ₂ upstream and downstream pressure, and the temperature control of the reaction.

So z. B. for PO as epoxy zinc carboxylate catalysts predominantly polycarbonates with> 90% carbonate linkages. she have high modulus of elasticity and low elongation at break and are tough and tough. Such tough-solid polycarbonates are suitable for. B. for production of molded parts.

Multimetal cyanide catalysts, on the other hand, tend to give PO Polycarbonates with 70 to 90% carbonate linkages. They have low modulus of elasticity and high elongation at break and are flexible. Such flexible polycarbonates are suitable for. B. for the production of Foils and films.

The former tough-tough polycarbonates are similar in modulus of elasticity and Elongation at break Polyesters such as polybutylene terephthalate (e.g. Ultradur® from BASF), the latter being similar in terms of flexible polycarbonates Young's modulus and elongation at break of aromatic-aliphatic copolyesters (e.g. Ecoflex® from BASF) or polyethylenes like LLDPE (linear low density polyethylene) or LDPE (low density polyethylene).

In particular, the polycarbonates according to the invention, if them using a zinc carboxylate catalyst were produced, a modulus of elasticity above 500 MPa, determined in Tensile test at 23 ° C on cylindrical strands with a diameter of 2.5 mm 25 mm clamping length, 10 mm measuring length standard travel, 50 mm / min Pulling speed and 10 kN pulling force.

In addition, the polycarbonates according to the invention, if they made using a multimetal cyanide catalyst an elongation at break of over 500%, determined in the tensile test at 23 ° C on cylindrical strands 2.5 mm in diameter at 25 mm Clamping length, 10 mm measuring length standard travel, 50 mm / min Pulling speed and 10 kN pulling force.

The details of the manufacture of the cylindrical strands and to measure the modulus of elasticity and the elongation at break are as follows: the Polycarbonates are at 60 to 80 ° C for 4 to 12 hours in a vacuum dried. There are 4 to 5 g of the material in one Melt flow capillary rheometer (e.g. type MP-D from Gottfert). After 3 to 4 minutes of preheating, the strands weigh 2.16 kg Load at 150 ° C through the rheometer nozzle (cylindrical nozzle of 2 mm diameter) extruded and allowed to cool in air. Tensile test: the approx. 50 mm long strands with a diameter of 2.5 mm with a tensile force of 10 kN and a train speed of 50 mm / min, the clamping length (distance of the Jaws) 25 mm and the measuring length standard path is 10 mm. The measurement is carried out in accordance with DIN 53455-3.

These polycarbonates are also the subject of the invention.

The choice of catalyst therefore essentially determines that Properties of the polycarbonates.

The inventive method allows the production of Polycarbonate molding compounds with customized, within further Limits of variable properties, especially tailor-made and variable mechanical properties.

The polycarbonates according to the invention, in particular with ethylene oxide manufactured polycarbonates are characterized by good Biodegradability from, d. H. they are by being in the ground Microorganisms, sunlight, hydrolysis or several of these mechanisms degraded comparatively quickly.

The invention therefore also relates to the Polycarbonates obtainable by the process according to the invention, in particular also those with at least 50, in particular at least 70% carbonate linkages in the polymer chain, and those with good biodegradability.

Thermoplastic molding compositions are also the subject of Invention containing the polycarbonates mentioned. Further Components of these molding compositions can be polymers, e.g. B. polyester like Polybutylene terephthalate, polyethylene, and biodegradable Polymers. Examples are for the latter aromatic-aliphatic copolyester (e.g. Ecoflex® from BASF), polymers based of lactic acid (polylactide) or starch (starch polymers), Polyanhydrides, polyhydroxybutyrates, polyethylene glycols, Polyvinyl alcohols, polyvinyl acetates, cellulose acetates and Starch acetates called.

They are known to the expert and z. B. described in the following writings, which is why further information is unnecessary:
M. Vert et al., Biodegradable Polymers and Plastics (Second International Scientific Workshop on Biodegradable Polymers and Plastics), Royal Society of Chemistry, Cambridge 1992, Special Publication 109;
Y. Doi et al., Biodegradable Plastics and Polymers (Proceedings of the Third International Scientific Workshop on Biodegradable Plastics and Polymers, Osaka), Elsevier, Amsterdam 1994, Studies in Polymer Science, 12;
GJ Griffin, Chemistry and Technology of Biodegradable Polymers, Blackie, London 1994.

The thermoplastic molding compositions can also be conventional Contain additives and processing aids. Such Additives and processing aids are lubricants and Mold release agents, colorants such as pigments and dyes, Flame retardants, antioxidants, light stabilizers, fibrous and powdery fillers and reinforcing agents and Antistatic agents in the amounts customary for these agents.

The molding compositions according to the invention can be prepared according to known mixing processes take place, for example under Melting in an extruder, Banbury mixer, kneader, roller mill or calenders at temperatures from 150 to 300 ° C. The components can be mixed "cold" without melting and that powdery or granulate mixture is only at the Processing melted and homogenized.

Moldings of all types, including foils, Films, coatings and fabrics as well as fibers, produce. The films can be produced by extrusion, rolling, Calendering and other processes known to the person skilled in the art take place. The molding compositions according to the invention are thereby heated and / or friction alone or with the use of emollients or other additives to form a processable film or a sheet (plate). Processing too Three-dimensional moldings of all kinds are made, for example by injection molding.

As coatings come e.g. B. coatings from surfaces Paper, wood, plastic, metal or glass.

Another object of the present invention is thus Use of the thermoplastic molding compositions according to the invention Manufacture of moldings, foils, films, coatings and Fibers. Furthermore, the use of the thermoplastic molding compositions available molding films, Films, coatings and fibers are the subject of the present Invention.

Examples 1. Feedstocks

The following catalysts were used:
Zn (Glu): zinc glutarate, produced as follows:
35 g of ground zinc oxide in 250 ml of absolute toluene were placed in a 1 liter four-necked flask equipped with a stirring bone, heating bath and a water circuit. After adding 52 g of glutaric acid, the mixture was heated to 55 ° C. for 2 hours with stirring. The mixture was then heated to boiling, the water of reaction being distilled off azeotropically until no more water passed over. The toluene was distilled off and the residue was dried at 80 ° C. in a high vacuum.

DMC: double metal cyanide compound, prepared as follows:
In a stirred tank with a volume of 800 l, equipped with a inclined blade turbine, dip tube for dosing, pH electrode, conductivity measuring cell and scattered light probe, 370 kg of aqueous hexacyanocobaltoic acid H ₃ [Co (CN) ₆ ] (cobalt content 9 g / l ) submitted and heated to 50 ° C with stirring. Subsequently, 209.5 kg of aqueous zinc acetate dihydrate solution (zinc content 2.7% by weight), which was also heated to 50 ° C., were metered in with stirring (stirring power 1 W / l) within 50 min. 8 kg of Pluronic® PE 6200 (this is an EO-PO block copolymer with 20% by weight of EO and an average molecular weight of about 2000 to 5000, available from BASF) and 10.7 kg of water were then added with stirring. Then 67.5 kg of aqueous zinc acetate dihydrate solution (zinc content: 2.7% by weight) were metered in with stirring (stirring energy: 1 W / l) at 50 ° C. within 20 min. The suspension was stirred at 55 ° C. until the pH had dropped from 3.7 to 2.7 and remained constant. The precipitation suspension thus obtained was then filtered off by means of a filter press and washed in the filter press with 400 l of water. The moist filter cake obtained was dried in a forced air oven at 60 ° C. to constant weight.

Commercial grades from BASF were used as monomers without further purification:
CO ₂ : carbon dioxide
EO: ethylene oxide
PO: propylene oxide

The inert reaction medium toluene was dried over sodium.

2. Test instructions for polymerization a) Make the catalyst anhydrous

The catalyst (type and amount see tables) was placed in a reactor. A 300 ml autoclave made of stainless steel, which was equipped with a mechanical stirrer, or a 3.5 l autoclave with a mechanical stirrer was used for the scale-up experiments (Tables 3A and 3B). After the reactor had been closed, it was flushed with N ₂ gas, heated to 130 ° C. under a stream of N ₂ and held at these conditions for 4 hours. Then allowed to cool to room temperature.

b) polymerization

The inert reaction medium toluene (amount see tables) was pressed into the reactor with CO ₂ gas. Then CO _{2 was} pressed into the reactor at room temperature (23 ° C.) until the CO ₂ admission pressure given in the tables was reached. The duration of this contacting of the catalyst with CO ₂ was 1 to 120 min, depending on the CO ₂ admission pressure and reactor volume. The epoxide (type and amount see tables) was then pressed into the reactor with CO ₂ gas and the reactor was then heated to the reaction temperature T _R given in the tables. Subsequently, CO _{2 was} pressed into the reactor at the reaction temperature T _R until the final CO ₂ pressure indicated in the tables was reached. The reactor was kept at the reaction temperature T _R for a certain time (see table for the duration), with no CO _{2 being} replenished. The mixture was then allowed to cool to room temperature.

c) processing

The reactor was vented and the reactor contents were in 1 liter Methanol, which is concentrated with 5 ml. Hydrochloric acid (37% by weight) was acidified, cast. A polymer precipitated, which filtered off and over Was dried overnight at 60 ° C in a vacuum. In some examples (identified by the suffix R in the tables) also the methanol liquid phase obtained on filtering on Rotary evaporator evaporated to dryness. You got one polymer-containing residue.

3. Measurements

In order to clarify whether the polymer obtained is a mixture (blend) of alternating polycarbonate (I in the above-mentioned scheme) and polyether homopolymer III or a random polyether carbonate copolymer II, an AMX 300 NMR spectrometer from Bruker ^{1 was used} H and ¹³ C NMR spectra of pure alternating polycarbonate I, of pure polyether homopolymer III and of the polymer obtained were recorded and compared with one another. As a result, the polymer precipitated was a polyether carbonate copolymer and not a blend.

The precipitated polymer, as well as that from the methanol liquid phase recovered polymer in the case of the R examples, were based on Molecular weights, glass transition and melting temperatures, as well as on the Share of carbonate linkages, and on by-products (cyclic Carbonates and polyethers).

The molecular weights of the polymers given in the tables (weight average M _w and number average M _n ) were determined by means of gel permeation chromatography (GPC). The details were as follows:
Eluent: hexafluoroisopropanol (HFIP)
Flow rate: 0.5 ml / min
GPC system: 150 C ALC / GPC from Waters
Detector: ERC 7510 differential refractometer from ERC
Columns: HFiP Gel guard column and HFiP Gel linear separation column, both from Polymer Laboratories
Calibration: with narrowly distributed polymethyl methacrylate standards with molecular weights M from 505 to 2,740,000 from PSS
Temperature: 42 ° C.

The glass transition temperatures T _g and melting temperatures T _m given in the tables were determined by means of differential scanning calorimetry (DSC) in accordance with DIN 53765. The details were as follows: heating from room temperature to 180 ° C., cooling to -100 ° C., heating to 180 ° C., rate 20 K / min in each case, determination in the second run.

The data given in the tables for the proportion of carbonate linkages in the polymer and for the presence of by-products (cyclic carbonates and polyethers) were determined on the basis of ¹ H-NMR spectra of the precipitated polymer. For this purpose, ¹ H-NMR spectra of the polymer were recorded on a ¹ H-NMR spectrometer from Bruker and evaluated qualitatively and quantitatively.

4. Results

The following tables summarize the results. The Tables labeled A contain the reaction conditions (see test instructions above) and those marked with B. Tables show the results.

It means:
Duration: time of reacting
M _w : weight average molecular weight M _w
M _n : number average molecular weight M _n
T _g : glass transition temperature of the polycarbonate
T _m : melting temperature of the polycarbonate
Proportion of CV: Proportion of carbonate linkages in the polymer
By-products: "no" with a content of cyclic carbonates and polyethers of less than or equal to 5% by weight, "yes" with a content of more than 5% by weight, in each case based on the polymer
-: not determined
V: for comparison
R: Examination of the residue from the methanol liquid phase.

Example 2V shows that the inventive method with a non-anhydrous catalyst not working. It proves that it is essential to the invention, the catalyst in anhydrous Insert form.

Examples 3 to 8V illustrate the influence of the variation in the CO ₂ final pressure. At final CO ₂ pressures of 150 to 50 bar (Examples 3 to 6), polycarbonates with molecular weights were used M _{w received} over 200,000, which contained a maximum of 5 wt .-% undesirable by-products (sum of cyclic carbonates and polyethers). In contrast, polycarbonates with molar masses were obtained at CO ₂ final pressures of 20 bar (Examples 7V to 8RV) M _w to about 110,000, which contained more than 5 wt .-% by-products.

The example pair 4/5 illustrates the variation of Amount of catalyst.

Examples 9V and 10 illustrate the influence of the variation in the reaction temperature T _R. At temperatures of 50 ° C (Example 9V), polycarbonates were obtained which contained more than 5% by weight of undesired by-products. In contrast, temperatures of 65 ° C. (Example 10) gave polycarbonates with a maximum of 5% by weight of by-products.

The example pair 10 / 10a illustrates the good reproducibility of the method according to the invention: the measured values are correct match. This also applies to the scale-up to larger ones Product quantities, see tables 3A and 3B below.

In Examples 11 to 15, zinc glutarate was used as the catalyst, not DMC. Polycarbonates, their molar masses, were obtained M _{w were} comparable to the polycarbonates produced by DMC. The proportion of carbonate linkages was 88 to 97% higher than that of polycarbonates via DMC.

The final CO ₂ pressure was varied from 20 to 100 bar in Examples 11 to 15, which resulted in different molar masses and proportions of carbonate linkages.

Examples 16 to 19 show that a reduction in the amount of catalyst and an increase in the amount of epoxy (PO) polycarbonates with high molecular weights M _w , results.

Tables 3A and B below illustrate a scale-up of the process to larger product quantities. An autoclave with a volume of 3.5 l instead of 300 ml was used.

Examples 20 to 23 show that a scale-up by a factor of 10 (Examples 20 and 21), or by a factor of 15 (Examples 20 and 22) or by a factor of 21 (Examples 20 and 23) was possible: in Example 20 used 24 ml PO, in example 21 240 ml PO, in example 22 360 ml PO and in example 23 500 ml PO. The Property profile of the polycarbonates obtained was comparable.

The inventive method is therefore also in terms of used or received quantities of substance flexible.

In Tables 1 to 3 above, propylene oxide was used as the epoxy. Tables 4A and 4B below summarize the results for ethylene oxide / CO ₂ copolymers.

Examples 24 to 26 show the influence of the variation of CO ₂ final pressure and reaction temperature T _R for EO as epoxy. At final CO ₂ pressures of 100 to 20 bar and temperatures of 50 to 80 ° C, polycarbonates according to the invention with molecular weights M _{w obtained} from at least 30,000.

For some selected polymers, the mechanical Properties examined. The results are as follows compiled.

5. Mechanical properties

The mechanical properties of the polycarbonates from Example 10 (copolymer of CO ₂ and PO with DMC catalyst) and from Example 12 (copolymer of CO ₂ and PO with Zn (Glu) catalyst) were determined and compared with those of other polymers. These other polymers were Ultradur® B 4520, a polybutylene terephthalate PBT (polyester) from BASF and Ecoflex®, an aromatic-aliphatic biodegradable copolyester from BASF.

To this end, strands were produced from the polymers as follows: the Polycarbonates were at 60 to 80 ° C for 4 to 12 hours in a vacuum dried. There were 4 to 5 g of the material in one Melt flow capillary rheometer (type MP-D from Gottfert). To The strands were preheated for 3 to 4 minutes with a load of 2.16 kg at 150 ° C through the nozzle of the rheometer (cylindrical nozzle of 2 mm Diameter) extruded and allowed to cool in air.

The measurement was carried out in a tensile test at 23 ° C, as follows: the approx. 50 mm long strands with a diameter of 2.5 mm were added a tensile force of 10 kN examined, the clamping length (Distance between the jaws) 25 mm and the measuring length standard path 10 mm scam. The tensile tests were used for better comparability two different train speeds, namely 5 mm / min and 50 mm / min, see Examples 28a and 28b.

The measurement was carried out in accordance with DIN 53455-3.

Table 5 summarizes the results. Table 5 Mechanical properties of the polycarbonates in comparison

Comparing Examples 27 and 28a showed that below Polycarbonate from Example 10 produced using DMC (here example 27) a much lower modulus of elasticity and one much higher elongation at break than using Zn (Glu) produced polycarbonate from Example 12 (here example 28a). The polycarbonate via DMC catalyst was therefore flexible and the polycarbonate via Zn (Glu) catalyst was tough.

Comparing Examples 28b and V1 shows that Polycarbonate via Zn (Glu) catalyst an E-module that the PBT Ultradur® comes close.

Comparing Examples 27 and V2 shows the polycarbonate via DMC catalyst, a modulus of elasticity and an elongation at break, which the Get close to polyester Ecoflex®.

The method according to the invention accordingly allows production of polycarbonates with interesting and tailor-made Property profiles.

Claims (15)

1. Process for the production of high molecular weight aliphatic polycarbonates with the following properties the weight-average molecular weight M _w , determined by means of gel permeation chromatography using hexafluoroisopropanol as eluent and polymethyl methacrylate standards, is 30,000 to 1,000,000, the content of cyclic carbonates and polyethers taken together is a maximum of 5% by weight, by polymerizing carbon dioxide with at least one epoxide of the general formula 1


in which the radicals R independently of one another represent hydrogen, halogen, -NO ₂ , -CN, -COOR or a hydrocarbon group with 1 to 20 C atoms, which may be substituted,
using at least one catalyst selected from the group consisting of zinc carboxylates and multimetal cyanide compounds,
characterized by
that the catalyst is used in anhydrous form, and
that the catalyst is first contacted with at least a portion of the carbon dioxide before adding the epoxy. 2. The method according to claim 1, characterized in that one make the catalyst anhydrous by turning it off before starting the polymerization in an inert gas stream or in vacuo to Warm water free. 3. The method according to claims 1 to 2, characterized characterized in that the epoxide is ethylene oxide, propylene oxide, butene oxide, Cyclopentene oxide, cyclohexene oxide, i-butene oxide, acrylic oxides or their mixtures used. 4. The method according to claims 1 to 3, characterized characterized in that as zinc carboxylates zinc glutarate, zinc adipate or mixtures thereof are used. 5. Process according to claims 1 to 4, characterized in that those of the general formula 2 are used as multimetal cyanide compounds,

M ¹ _a [M ² (CN) _b A _c ] _d .fM ¹ _g X _n .hH ₂ O.eL.kP (2)

in which mean:
M ¹ at least one metal ion selected from the group comprising Zn ²⁺ , Fe ²⁺ , Fe ³⁺ , Co ²⁺ , Co ³⁺ , Ni ²⁺ , Mn ²⁺ , Sn ²⁺ , Mo ⁴⁺ , Mo ⁶⁺ , Al ³⁺ , V ⁴⁺ , V ⁵⁺ , Sr ²⁺ , W ⁴⁺ , W ⁶⁺ , Cr ²⁺ , Cr ³⁺ , Cd ²⁺ , Pd ²⁺ , La ³⁺ , Ce ³⁺ , Ce ⁴⁺ , Eu ³⁺ , Mg ²⁺ , Ti ³⁺ , Ti ⁴⁺ , Ag ⁺ , Rh ²⁺ , Ru ²⁺ , Ru ³⁺ ,
M ² at least one metal ion selected from the group comprising Fe ²⁺ , Fe ³⁺ , CO ²⁺ , CO ³⁺ , Mn ²⁺ , Mn ³⁺ , V ⁴⁺ , V ⁵⁺ , Cr ²⁺ , Cr ³⁺ , Rh ³⁺ , Ru ³⁺ , Ir ³⁺ ,
where M ¹ and M ^{2 can be the} same or different,
A at least one anion selected from the group consisting of halide, hydroxide, sulfate, hydrogen sulfate, carbonate, hydrogen carbonate, cyanide, thiocyanate, isocyanate, cyanate, carboxylate, oxalate, nitrate, nitrosyl, phosphate, dihydrogen phosphate, hydrogen phosphate,
X at least one anion selected from the group comprising halide, hydroxide, sulfate, carbonate, hydrogen carbonate, cyanide, thiocyanate, isocyanate, cyanate, carboxylate, oxalate, nitrate,
where A and X can be the same or different,
L at least one water-miscible ligand selected from the group consisting of alcohols, aldehydes, ketones, ethers, polyethers, esters, polyesters, polycarbonates, ureas, amides, nitriles, sulfides, amines, ligands with pyridine nitrogen, phosphides, phosphites, phosphines , Phosphonates, phosphates,
P at least one organic additive selected from the group comprising polyethers, polyesters, polycarbonates, polyalkylene glycol sorbitan esters, polyalkylene glycol glycidyl ethers, polyacrylamide, polyacrylamide-co-acrylic acid), polyacrylic acid, polyacrylamide-co-maleic acid), polyacrylonitrile, polyalkylacrylates, polyalkyl methacrylates, polyvinyl ether, polyethyl ether, polyvinyl ether , Polyvinyl alcohol, poly-N-vinylpyrrolidone, poly (N-vinylpyrrolodone-co-acrylic acid), polyvinyl methyl ketone, poly (4-vinylphenol), poly (acrylic acid-co-styrene), oxazoline polymers, polyalkyleneimines, maleic acid, maleic anhydride copolymer, hydroxyethyl cellulose, polyacetete, ionic surface-active and surface-active compounds, bile acid and the salts, esters and amides of bile acid, carboxylic acid esters, polyhydric alcohols, glycosides,
where a, b, d, g and n are whole or fractional numbers greater than zero, and
where c, f, h, e and k are whole or fractional numbers greater than or equal to zero, and
where a, b, c, d, g and n are chosen so that the electroneutrality of the cyanide compound M ¹ [M ² (CN) A] or the compound M ¹ X is ensured. 6. Process according to claims 1 to 5, characterized in that a compound is used as the multimetal cyanide compound, which is obtainable by reacting aqueous hexacyanocobaltoic acid H ₃ [Co (CN) ₆ ] with aqueous zinc acetate solution. 7. The method according to claims 1 to 6, characterized in that it essentially comprises the following process steps: 1. Make the catalyst anhydrous 2. Placing the anhydrous catalyst in a polymerization reactor 3. Optional addition of an inert reaction medium 4. Add carbon dioxide 5. Add the epoxy 6. Warm the reactor to the reaction temperature 7. Optionally add more carbon dioxide 8. After the polymerization reaction has subsided, work up the reactor contents onto the polycarbonate, steps 5 and 6 can be interchanged. 8. Aliphatic polycarbonates, obtainable by the process according to claims 1 to 7. 9. Aliphatic polycarbonates according to claim 8, characterized by having at least 70% carbonate linkages in the Polymer chain included. 10. aliphatic polycarbonates according to claims 8 to 9, characterized by good biodegradability. 11. Aliphatic polycarbonates according to claims 8 to 10, the using a zinc carboxylate catalyst be produced, characterized by a modulus of elasticity above 500 MPa, determined in a tensile test at 23 ° C on cylindrical strands of 2.5 mm diameter with 25 mm clamping length, 10 mm measuring length Standard travel, 50 mm / min pulling speed and 10 kN pulling force. 12. Aliphatic polycarbonates according to claims 8 to 10, the using a multimetal cyanide catalyst be produced, characterized by an elongation at break above 500%, determined in a tensile test at 23 ° C on cylindrical Strands 2.5 mm in diameter with a clamping length of 25 mm, 10 mm Measuring length standard path, 50 mm / min train speed and 10 kN Traction. 13. Thermoplastic molding compositions containing aliphatic Polycarbonates according to claims 8 to 12. 14. Use of the thermoplastic molding compositions according to claim 13 for the production of molded parts, foils, films, Coatings and fibers. 15. Moldings, foils, films, coatings and fibers from the thermoplastic molding compositions according to claim 13.