DE4223016C2 - Process for the production of polycarbonates - Google Patents

Description

The present invention relates to a process for the preparation of aromatic polycarbonates with molecular weights _w of 15,000 to 200,000 and OH-end group contents <250 ppm from diphenols, carbonic acid diesters and optionally branching by melt transesterification to oligocarbonates with a _w of 2000 to 10,000 and OH end group contents of less than 50 mol% but more than 20 mol% and crystallization of these oligocarbonates, which is characterized in that the crystalline oligocarbonates in the solid phase in the presence of a boiling organic entrainer for the cleavage products of the polycondensation, that the crystalline oligocarbonates do not dissolve or melt, be polycondensed.

The production of aromatic oligo- / polycarbonates after the melt transesterification process is literature known and for example in the EP applications 338 085, 360 578, 351 168 and the DP 10 31 512 described.  

The crystallization of oligo- / polycarbonates is e.g. B. in J. Polymer Sci. Part A-2, 4, 327 (1966); J. Polymer Sci. Phys. Ed. 14, 1367 (1976); J. Polymer Sci. polymer Letters Ed. 16: 419 (1978); U.S. Patent 3,112,292; 4,631,338; Polymer Engineering and Science 16, 4, 276 (1976) and described in EP application 338 085.

The solid phase polycondensation of oligocarbonates, the were shown with the help of the melt transesterification in EP application 338 085, in US Pat. No. 4,948,871 and described in WO 90/07536.

In the references mentioned above and there References cited are for the solid phases polycondensation as a medium to remove the gap products either large quantities of a gas, high vacuum or a combination of vacuum and trailing gas wrote the large equipment technical expenses require.

It has now surprisingly been found that the Use of suitable organic entrainer on a way of eliminating the condensation to the high molecular polycarbonate gap products succeed. As a result, the Reini supply and the circulation of large amounts of gas and a Eliminate complex technology for vacuum operation that will.

Organic, liquid entraining agents in the sense of the method according to the invention are:
aliphatic hydrocarbons with 4 to 20 carbon atoms,
aromatic hydrocarbons with 6 to 18 carbon atoms,
Ketones with 6 to 12 carbon atoms,
Alcohols with 6 to 12 carbon atoms and
Esters of 4 to 18 carbon atoms;
preferred organic, liquid entraining agents are:
aliphatic hydrocarbons with 6 to 18 carbon atoms,
Halogen and aliphatic substituted aromatic hydrocarbons with 6 to 12 carbon atoms, with 1 halogen atom and up to 4 alkyl substituents,
Ketones with 6 to 10 carbon atoms,
Alcohols with 6 to 8 carbon atoms and
Esters of 4 to 12 carbon atoms;
Particularly preferred organic, liquid entraining agents are:
Methylpentane, cyclohexane, octane, isooctane, nonane, isononane, dedecane, undecane, limonene, xylene, mesitylene, durol, diisopropylbenzene, cumene, cymene, indane, indene, chlorotoluene, chloroxylene, chlorocumol, cyclohexanone, cyclohexanol and phenylacetylhexanol, dimethyl
Mesitylene, cymene, diisopropylbenzene, limonene, isooctane, isononane, undecane, dodecane and isododecane are very particularly preferred.

The aromatic oligocarbonates which are produced in the context of the process according to the invention are understood to mean the known homooligocarbonates, cooligocarbonates and mixtures of these oligocarbonates which are derived, for example, from the following diphenols:
Hydroquinone,
Resorcinol,
Dihydroxydiphenylene,
Bis (hydroxyphenyl) alkanes,
Bis (hydroxyphenyl) cycloalkanes,
Bis (hydroxyphenyl) sulfides,
Bis (hydroxyphenyl) ethers,
Bis (hydroxyphenyl) ketones,
Bia (hydroxyphenyl) sulfones,
Bis (hydroxyphenyl) sulfoxides,
α, α′-bis (hydroxyphenyl) diisopropylbenzenes,
as well as their nuclear alkylated and nuclear halogenated compounds.

Preferred diphenols are e.g. B .:
2,2-bis (4-hydroxyphenyl) propane,
2,4-bis (4-hydroxyphenyl) -2-methylbutane,
1,1-bis (4-hydroxyphenyl) -p-diisopropylbenzene,
2,2-bis (3-methyl-4-hydroxyphenyl) propane,
2,2-bis (3-chloro-4-hydroxyphenyl) propane,
Bis- (3,5-dimethyl-4-hydroxyphenyl) methane,
2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane,
Bis (3,5-dimethyl-4-hydroxyphenyl) sulfone,
2,4-bis (3,5-dimethyl-4-hydroxyphenyl) -2-methylbutane,
1,1-bis (3,5-dimethyl-4-hydroxyphenyl) -p-diisopropyl benzene,
2,2-bis (3,5-dichloro-4-hydroxyphenyl) propane,
2,2-bis (3,5-dibromo-4-hydroxyphenyl) propane and
1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane.

Diphenols are particularly preferred
4,4'-dihydroxydiphenyl,
4,4'-dihydroxydiphenyl sulfide,
2,2-bis (4-hydroxyphenyl) propane,
2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane,
2,2-bis (3,5-dichloro-4-hydroxyphenyl) propane,
2,2-bis (3,5-dibromo-4-hydroxyphenyl) propane,
1,1-bis (4-hydroxyphenyl) cyclohexane and
1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane.

Those polycarbonates which are very particularly preferred are the above diphenols to max. 50 mol% and above also contain bisphenol A.

The oligocarbonates can be branched by using small amounts of branching agents. Some suitable branches are:
Phloroglucin,
4,6-dimethyl-2,4,6-tri- (4-hydroxyphenyl) -hepten-2,
4,6-dimethyl-2,4,6-tri- (4-hydroxyphenyl) heptane,
1,3,5-tri- (4-hydroxyphenyl) benzene,
1,1,1-tri- (4-hydroxyphenyl) ethane,
Tri- (4-hydroxyphenyl) phenylmethane,
2,2-bis- (4,4-bis- (4-hydroxyphenyl) cyclohexyl) propane,
2,4-bis (4-hydroxyphenyl-isopropyl) phenol,
2,6-bis (2-hydroxy-5'-methyl-benzyl) -4-methylphenol,
2- (4-hydroxyphenyl) -2- (2,4-dihydroxyphenyl) propane,
Hexa- (4- (4-hydroxyphenyl-isopropyl) phenyl) orthotere phthalic acid ester,
Tetra (4-hydroxyphenyl) methane,
Tetra- (4- (4-hydroxyphenyl-isopropyl) phenoxy) methane,
1,4-bis (4,4 '' - dihydroxytriphenyl) methyl) benzene
and particularly
α, α ′, α ′ ′ - tris- (4-hydroxyphenyl) -1,3,5-triisopropylbenzene.

Other possible branching agents are 2,4-dihydroxybenzoe acid, trimesic acid, cyanuric chloride and 3,3-bis- (3- methyl-4-hydroxyphenyl) -2-oxo-2,3-dihydroindole.

The 0.05 to 2 mol% optionally to be used, based on diphenols used, on branches, can be used together with the diphenols.

Suitable carbonic acid diesters for the production of Oligocarbonates are diaryl carbonates such as dicresyl carbonates, chlorophenol carbonates, isopropylphenyl carbonate prefers diphenyl carbonate.

The reactant ratio of diphenol to carbonic acid diester is between 1: 1.01 to 1.30 mol, preferably between 1: 1.02 to 1.15 mol.  

The aromatic oligocarbonates from the melt reorganization should have average molar masses M _w of 2,000 to 10,000, determined by measuring the rel. Solution viscosity in dichloromethane or in mixtures of equal amounts by weight of phenol / o-dichlorobenzene or light scattering, and OH end group contents of less than 50 and more than 20 mol%, preferably between 45 and 30 mol%.

It may be beneficial to transesterify to the oligo small amounts of carbonates (0.05 ppm to 0.1% by weight) accelerate from catalysts. As catalysts come u. a. LiOH, NaOH, Na₂CO₃, Ca (OH) ₂, CaCO₃, tetra alkyl titanate, dibutyldibutoxytin, quinoline, triphenyl phosphine, boric acid and its esters, tetraalkylammonium hydroxide, Mg (OH) ₂ or combinations of these catalysts goals in question. Mostly there are traces (<1 ppm) of alkali and Alkaline earth metal hydroxides sufficient.

The crystallization of the oligocarbonates succeeds according to the methods known from the literature; e.g. B. by means of solvents e.g. B. acetone, methylene chloride, dimethyl carbonate, etc. or thermal crystallization, according to the above Literature.

The solid phase condensation according to the invention The process is generally carried out in such a way that the crystalline oligocarbonates in the entrainer dispersed, the weight ratio of tow medium to oligocarbonate 1:99 to 99: 1, preferably 95: 5 to 20:80, particularly preferably 90:10 to 30:70.  

This suspension is then heated to a temperature between the glass transition temperature and the Crystal melting point. For bisphenol A polycarbonate this range is between 150 and 230 ° C, preferably between 160 and 230 ° C, particularly be preferably between 180 and 225 ° C.

The entrainer must be used during the solid phase condensation be brought to the boil. If its boiling point too is low, with a corresponding overpressure, if it is too high with a corresponding negative pressure be worked.

From the transition distillate, the cleavage product z. B. Phenol are removed. This can be done, for example Extraction with a polar, with the entrainer immiscible compound such as water, ethylene glycol, Glycerin, formamide or tetramethylene sulfone happen. The extracted phenol can be recovered by distillation will. Traces of the extractant can also be removed from the entrainer by distillation. Water, for example, can be easily removed with Acetrope remove distillation.

Another way to clean the towing vehicle Means consists in the adsorption of the phenol example on aluminum silicates or activated carbons.

The cleaned entrainer is in the boiling Sus pension and in this way as long as Cycle out until the required amount of phenol is made  the solid phase is removed and the polycarbonate desired molecular weight.

The aluminosilicates to be used according to the invention are known as such from the literature, see e.g. B. Kirk-Othmer "Encyclopedia of Chemical Technology" 2nd Ed. 1964, Vol. 5 pp. 541-561.

Can be used according to the invention as classified in the article mentioned z. B. kaolin types such as kaolinite, dickerite, nacrite (all Al₂O₃ × 2 SiO₂ × 2 H₂O) or anauxite (Al₂O₃ × 3 SiO₂ × 2 H₂O) or halloysite (Al₂O₃ × 2 SiO₂ × 2 H₂O) or endellite (Al₂O₃ × 2 SiO₂ × 4 H₂O) and the spinel types produced by heating from the kaolin types, also serpentine types, in which 3 Mg ions, 2 Al ions - based on the kaolin types - have replaced (Mg₃Si₂O₅ (OH) ₄) . The serpentine types also include amesite ( ^- (Mg₂Al) (SiAl) O₅ (OH) ₄) and cronstedit (Fe ²⁺ Fe ³⁺ ) (SiFe ³⁺ ) O₅ (OH₄) and chamosit (Fe ²⁺ , Mg) _2.3 (Fe ³⁺ Al) _0.7 (Si _1.14 Al _0.86 ) O₅ (OH) ₄ and the z. T. also synthetically accessible nickel or cobalt species.

Furthermore, alumosilicate of the montmorillonite type are used such. B.

Montmorillonite [Al _1.67 Mg _0.33 (Na _0.33 )] Si₄O₁₀ (OH) ₂
Beidellite Al _2.17 [Al _0.33 (Na _0.33 )] Si _3.17 O₁₀ (OH) ₂
Nontronite Fe ³⁺ [Al _0.33 (Na _0.33 )] Si _3.67 O₁₀ (OH) ₂
Hectorite Mg _2.67 Li _0.33 (Na _0.33 )] Si₄O₁₀ (OH, F) ₂
Saponite Mg _3.0 [Al _0.33 (Na _0.33 )] Si _3.67 ] O₁₀ (OH) ₂
Sauconite [Zn _1.48 Mg _0.14 Al _0.74 Fe ³⁺ ] [Al _0.99 Si _3.01 ] O₁₀ (OH) ₂X _0.33

as well as types containing Cu ²⁺ , Cn ²⁺ or Ni ²⁺ (X halogen) such as Volkoskoit, Medmontit or Pimelit.

Such clays can be used alone or as a mixture of 2 or more clays can be used contain common impurities for these natural products ten, such as B. are common in bentonite (= Montmorillo nite with remains of feldspar, quartz etc.).

Preferred are those described as "montmorillonite types" alumina and particularly preferably montmorillonite itself. Also preferred are aluminosilicates of the type of Zeolites.

The zeolites to be used according to the invention are concerned it is crystalline, water-containing aluminosilicates, syn thetized or naturally occurring, with framework structure (See D.W. Breck in "Zeolite Molecular Sieves", Wiley In terscience, 1974, pp. 133 to 180; Ullmann's encyclopedia der technical chemistry, 4th ed., volume 17, pp. 9 to 18, Verlag Chemie, Weinheim, New York). Those are preferred of the following formula:

M _{2 / n} O Al₂O₃ × SiO₂yH₂O

in which

M for protons or metal cations of group Ia, IIa, IIIa, IVa, Va, VIa, VIIa, VIIIa, Ib, IIb, IIIb and IVb, preferably for protons and metal cations of group Ia, IIa, IVa and IVb, particularly preferably for protons and ions Na⁺, K⁺, Cs⁺, Ca⁺, Mg ²⁺ , Zn ²⁺ , La ³⁺ , Pr ³⁺ and Ce ³⁺
n stands for the valence of the metal cation,
x represents the molar ratio SiO₂ / Al₂O₃, where x can be a number from 1.0 to 50.0, preferably 2.0 to 25.0 and
y represents a number from 0.1 to 9.

Zeolites are suitable for the process according to the invention structure A and faujasite structure (type X and Y), L, ZSM, mordenite, offretite, phillipsite, sodalite, further Zeolite-like materials such as AlPO's, SAPO's and beson Zeolites with structure A, faujasite Structure (X, Y type), L, mordenite, offretite and further SAPO’s, AlPO′s and MeAPO’s), are particularly suitable Structure A zeolites of the faujasite structure (X and Y) and mordenite.

Activated carbon in the sense of the invention is activated carbon fabric made from different carbon sources Intermediate products can be produced. The procedures for Activation can also be quite different.  

Activated carbons are obtained, the BET surfaces from 200 to 3000 m²g, preferably 300 to 2000 m²g, be particularly preferably have 500 to 1,500 m² / g.

Starting materials for the production of activated carbons are for example sawdust and other wood waste, straw, different types of coal, such as bitumen or lignite, Nut shells, mineral oil tars, lignin, polysaccharides, poly acrylonitrile, bone, peat. Furthermore, Kokspro Lignite or hard coal products are used.

Preferred are: wood, cellulose, lignin, bitumen and Lignite, peat or hard coal and lignite coke. The production of the activated carbons is known to the person skilled in the art and described in the literature (Ullmann’s Enzyklopedia of Industrial Chemistry 5th Ed. Vol A 5, 1986, pages 124 to 140 and the cit. Lit.).

During the solid phase condensation is due to temperature regulation to ensure that the suspended part Chen the crystalline oligo- or polycarbonate not glue or bake. The response time of the hard phase condensation lasts depending on the type, molecular weight and Different crystallinity of the oligocarbonate used the long one; generally preferred between 2 h and 20 h wise between 4 h and 12 h.

According to the solid-phase condensation process according to the invention, polycarbonates with M _w values of 15,000 to 200,000, preferably 19,000 to 60,000 and OH end group contents of less than 250 ppm are obtained in an organic entrainer. (M _w determined by measuring the relative solution viscosity in dichloromethane).

Those obtainable by the process according to the invention Polycarbonates occur in crystalline form and can by conventional processing methods over the melt converted to the amorphous state and to any shape bodies, for example to semi-finished products, plates, foils and containers processed on the usual machines the one that, like the well-known thermoplastic, aroma tables polycarbonates find technical use, for example in the electronics industry or in motor vehicles tool building.

Before or during the processing of the invention available polycarbonates can the usual additives, such as stabilizers, mold release agents, flame retardants, Pigments, finely divided minerals and fiber added in the usual way and in the usual amount are, for example alkyl and aryl phosphites, -phos phates, phosphines, low molecular weight carboxylic acid esters, Halogen compounds, salts, chalk, quartz flour, glass and Carbon fibers.

Furthermore, the poly obtainable according to the invention carbonates other polymers are mixed, z. B. Polyolefins, polyurethanes or polystyrenes.  

These mixtures can also be prepared in the usual way, are processed into moldings and in for this Gemi technically known manner.

Examples example 1 a) Instructions for the synthesis of an oligocarbonate

In a 2 l flat ground pot with heating jacket, base Opening, column, gas inlet and outlet and intensive 684.9 g (3 mol) of bisphenol A, 661.3 g are stirred (3.1 mol) diphenyl carbonate and 8 mg (19.58 mol ppm Na) Sodium bisphenolate entered as a catalyst. The The reaction vessel is gassed with nitrogen 5 times and evacuated to remove the atmospheric oxygen. Under the reaction is heated with a gentle stream of nitrogen vessel to 250 ° C and stirred as soon as the reactants are melted. Then the print in one Period of 90 minutes taking into account a conti Nuclear distillation speed to 1 mbar reduced so that after a further 5 min the resulting Oligocarbonate has a relative solution viscosity of 1.080 has reached.

b) Crystallization of the oligocarbonate

The cooled oligocarbonate thus obtained is now in the universal mill from Jahnke und Kunkel GmbH & Co KG, IKA-Werk, type M 20, ground for 30 s and then crystallized by incorporation in acetone. The crystal line oligocarbonate is filtered and dried.  

c) Solid phase polycondensation

20 g of this oligomer are now in a 500 ml Three-necked flask with internal thermometer and extraction apparatus with attached reflux condenser with 180 g Un decane offset. In the extraction apparatus is as Molecular sieve for the cleavage products 10 g zeolite K-Y used. Now heat for 1 h at 180 ° C and then 7 h at 200 ° C. A crystalline, colorless is obtained Polycarbonate with a relative solution viscosity (Di chloromethane, 25 ° C, 5 g / l) of 1.254.

Example 2

As example 1, only in the last phase the oligo carbonate production instead of 5 min 8 min high vacuum sets. The resulting oligocarbonate has a relative Solution viscosity reached 1.110.

This oligocarbonate is made according to the regulation implemented under Example 1. You get a crystalline, colorless polycarbonate with a relative solution viscosity density (dichloromethane, 25 ° C, 5 g / l) of 1.296.

Example 3

As example 4, only in the last phase the oligo carbonate production instead of 5 min 2 min high vacuum sets. The resulting oligocarbonate has a relative Solution viscosity reached 1.065.  

This oligocarbonate is made according to the regulation implemented under Example 1. You get a crystalline, colorless polycarbonate with a relative solution viscosity density (dichloromethane, 25 ° C, 5 g / l) of 1.222.

Example 4

Carrying out the experiment as in Example 1, except that instead of 20 g of oligocarbonate in the solid-phase polycondensation, 50 g of crystalline oligocarbonate are used. A crystalline, colorless polycarbonate with a relative solution viscosity (dichloromethane, 25 ° C., 5 g / l) of 1.248 (M _w = 24 800) is obtained.

Claims (3)

1. Process for the preparation of aromatic polycarbonates with molecular weights (M _w ) of 15,000 to 200,000 and OH end group contents <250 ppm from diphenols and carbonic acid diesters and optionally branching by melt transesterification to oligocarbonates with an M _w of 2000 to 10,000 and OH- End group contents of less than 50 mol% but more than 20 mol% and crystallization of these oligocarbonates, characterized in that the crystalline oligocarbonates in the solid phase in the presence of a boiling organic entrainer for the cleavage products of the polycondensation, which does not dissolve the crystalline oligocarbonates or melts, are polycondensed, the weight ratio of entrainer to oligocarbonate being 1:99 to 99: 1. 2. The method according to claim 1, characterized in that the weight ratio 95: 5 to 20: 80. 3. The method according to claim 1, characterized in that the weight ratio 90: 10 to 30: 70.