EP1922365A1

EP1922365A1 - Polycarbonate moulding compound exhibiting improved rheological properties

Info

Publication number: EP1922365A1
Application number: EP06776868A
Authority: EP
Inventors: Alexander Meyer; Frank Buckel
Original assignee: Bayer MaterialScience AG
Current assignee: Covestro Deutschland AG
Priority date: 2005-08-26
Filing date: 2006-08-16
Publication date: 2008-05-21
Also published as: TW200728342A; US20070049705A1; WO2007022902A1; CN101253244A; JP2009506144A; KR20080038250A; DE102005040464A1

Abstract

The invention relates to an epoxy polycarbonate-containing resin of formula (1) exhibiting improved rheological properties for comparable optical properties.

Description

Polvcarbonate molding compounds with improved rheological properties

The invention relates to compositions comprising polycarbonate and special epoxy resins, which are distinguished by improved rheological properties with otherwise identical optical properties.

For the processing of polycarbonates or polyester carbonates, these should have a particularly good flow properties. A flow improvement of polycarbonate or polyester carbonate can be achieved by various means. The easiest way is to reduce the molecular weight, but with the deterioration of the mechanical properties, e.g. the impact resistance and in particular the notched impact strength, is connected.

Furthermore, the flowability of polycarbonate can be increased via low molecular weight additives. In JP-A 2001226576, a low molecular weight polycarbonate is added to a higher molecular weight polycarbonate. In general, however, these low molecular weight additives may result in the optical quality, e.g. the transmission or yellowness index (YI) is lowered. Furthermore, low molecular weight additives often cause deposits on the injection molded parts (plate out) and thus reduce the quality of the injection molded body. Furthermore, the mechanical properties of the polycarbonates can be greatly reduced by these additives, whereby an important material advantage for the use of polycarbonate is lost.

Special comonomers can also improve the flowability of the resulting copolycarbonates over conventional bisphenol A (BPA) polycarbonate. However, this is often associated with a change in the property spectrum. Thus, the glass transition temperature can be significantly reduced. As by J. Schmidhauser and PD Sybert in J. Macromol. Be. - Pol. Rev. 2001, C41, 325-367 describes the use of bis (4-hydroxyphenyl) dodecane leads to an extremely low glass transition temperature of 53 ⁰ C in the resulting poly-carbonate. The copolymerization of BPA with various aliphatic dicarboxylic acids, as described, for example, in US Pat. No. 5,321,114, likewise leads to a lowering of the glass transition temperature.

WO 2002/038647 discloses the use of long-chain alkylphenols as chain terminators in order to improve flowability.

In general, these modified polycarbonates are very expensive to produce and therefore associated with high costs. Often, the particular comonomers and / or molecular weight regulators are not commercially available and must be elaborately synthesized. Another way to improve the theological properties of polycarbonate, the use of polycarbonate blends, ie the mixture of polycarbonates with other polymers such as polyester. Such blends are described, for example, in JP-A 2002012748.

However, the polymer properties of these polycarbonate blends are sometimes significantly different from standard bisphenol A polycarbonate and thus not necessarily for the same application. Thus, the thermal stability, the optical properties, the heat dimensional stability (reduction of the glass transition temperature) and the mechanical properties differ in some cases significantly from those of standard polycarbonate.

Mixtures of epoxy resins with engineering thermoplastics, e.g. Poly (methyl methacrylate) and / or polycarbonate have already been described by E.M. Woo, M.N. Wu in Polymer 1996, 37, 2485-2492. These epoxy resins differ significantly from the compositions of the invention. E.M. Woo et al. report a deleterious effect, especially of epoxy resins containing hydroxyl groups, on polycarbonate. It comes with thermal stress of the blend to a molecular weight reduction. This harmful influence is not observed in the blends described here.

No. 3,978,020 uses certain epoxy compounds in combination with phosphorus compounds for modifying polycarbonate. These epoxy compounds are structurally different from the epoxy resins of the general formula (I) of the present invention.

EP-A 718 367 discloses mixtures of epoxy resins which, however, are structurally different from the epoxy resins according to the invention with aromatic polycarbonates. These compositions are characterized by high corrosion resistance.

In DE-A 2 400 045, specific aromatic or aliphatic epoxy compounds are used in polycarbonate compositions to improve the hydrolytic stability at elevated temperatures.

In DE-A 2019325 polycarbonate mixtures are described, consisting of polycarbonate and epoxy-containing pigments. The epoxy compounds are used in amounts of 5 to 100 wt .-% based on the pigment content and thereby largely stabilized against wet degradation. From DE-A 2327014, polycarbonates filled with quartz mineral and / or TiO _{2 are} known, which contain an epoxide group-containing vinyl polymer, whereby the molecular weight degradation is prevented with virtually unchanged mechanical properties.

From JP-A 63117030 epoxy resins are known which are modified with phosphinic acid derivatives. However, these epoxy resins differ significantly from the epoxy resins described herein. Further, the substances described in JP-A 63117030 were not used in polycarbonate.

JP-A 63271357 describes hydroxalkyl-modified epoxy resins. However, these epoxy resins differ structurally from the epoxy resins described herein. Furthermore, the substances described in JP-A 63271357 were not used in polycarbonate.

Although the compositions described in the prior art partly improve the flowability of the respective polycarbonate, at the same time the optical properties such as transparency, transmission and yellowness index (YI) but also other properties such as the "plate-out" behavior deteriorate Production of large-area, transparent injection-molded articles such as spreading discs is therefore not suitable for the use of such additives in polycarbonate.

The object of the present invention is therefore to provide a polycarbonate composition having improved flow properties while maintaining optical properties and good processability. Surprisingly, it has been found that compositions of polycarbonate and special oligomeric epoxy resins have excellent flow properties with simultaneously good optical properties. In addition, the erfϊndungsgemäßen epoxy resins can be incorporated.

The present invention therefore provides the oligomeric epoxy resins of the formula (I)

(I) woπn - A -

R ^1, R ² are independently H, CpCπ alkyl, phenyl or benzyl, or together form a cyclic C ₅ -C signify _2-alkyl radical, preferably H or methyl or together are the cyclohexyl radical,

R ^{3 is} an optionally substituted aryl, benzyl, optionally branched C ₁ -C ₁₈ -alkyl or cyclic C ₅ -C 12 -alkyl radical,

n for a number-average value of 0.5-20, preferably for a number-average

Value from 1 to 9, particularly preferably for a number-average value of 1 to 4, and

q is 0 or 1, preferably 1.

The use of the oligomeric epoxy resins of the formula (I) as flow agents in polycarbonate or polyester carbonate is advantageous.

Another object of the present invention are therefore compositions containing

A) 95 to 99.9 wt .-%, preferably 97 to 99 wt .-% polycarbonate and

B) 0.1 to 5 wt .-%, preferably 1 to 3 wt .-% epoxy resin of the formula (I).

Another object of the invention is the preparation of a masterbatch by adding the oligomeric epoxy resin in polycarbonate in an amount of 5 to 20 wt .-% based on the weight of the masterbatch. The invention likewise provides a process for the preparation of the compositions according to the invention in which a calculated amount of masterbatch is mixed with polycarbonate present in the form of its melt or a solution, and wherein the amount of masterbatch used is calculated such that the oligomeric epoxy resin in an amount of 0.1 to 5 wt .-%, preferably 1 to 3 wt .-% based on the total composition.

Another object of the invention is the use of the composition of the invention for the production of extrudates and moldings of any kind.

The composition of the invention is advantageously used for the production of optical data carriers and glazings.

Another object of the invention are the extrudates containing the composition of the invention. Another object of the invention are the moldings containing the composition of the invention.

The components of the polycarbonate compositions which are suitable according to the invention are then explained by way of example.

Component A

The aromatic polycarbonates used in the polycarbonate mixtures according to the invention may be both homopolycarbonates and copolycarbonates; The polycarbonates may be linear or branched in a known manner.

As already described in DE-A 2 119 799, the production of polycarbonates takes place with the participation of phenolic end groups, by the phase boundary process or even by the homogeneous phase process. Aromatic polycarbonate prepared by both processes can be used in the composition of the present invention.

The preparation of polycarbonate by the interfacial process is known in the art as described by H. Schnell, Chemistry and Physics of Polycarbonates, Polymer Reviews, Vol. 9, Interscience Publishers, New York 1964 p. 33 et seq., And Polymer Reviews, Vol , Condensation Polymers by Interfacial and Solution Methods, as well as Paul W. Morgan, Interscience Publishers, New York 1965, Vm, p.

However, the aromatic polycarbonates for the composition according to the invention can also be prepared from diaryl carbonates and diphenols by the known polycarbonate process in the melt, the so-called melt transesterification process as described in WO-A 01/05866 and WO-A 01/05867. At the same time, however, aromatic polycarbonates are also from transesterification processes (acetate process and phenyl ester process) as described in US-A 3,494,885, US-A 4,386,186, US-A 4,661,580, US-A 4,680,371 and US-A 4,680,372 , EP-A 26 120, EP-A 26 121, EA 26 684, EP-A 28 030, EP-A 39 845, EP-A 39 845, EP-A 91 602, EP-A 97 970, EP-A 79 075, EP-A 146 887, EP-A 156 103, EP-A 234 913 and EP-A 240 301 as well as in DE-A 1 495 626 and DE-A 2 232 977 are described, can be used.

Component B

In the epoxy resins of the formula (I), the index n is preferably selected so that a number average molecular weight of 340 to 10,000, preferably 700 to 4000 is achieved. The number average molecular weight is measured by gel permeation polystyrene standard chromatography using THF as the solvent and measuring at room temperature.

The epoxy resins which serve as starting compounds for the preparation of the epoxy resins of the formula (I) according to the invention are known and can be prepared from bisphenol A and epichlorohydrin, as described for example in Kirk Othmer "Encyclopedia of Chemical Technology" 4th Ed. Vol. 9, p ., described ff, it is also commercially available epoxy resins such as Epikote ^® 1001, the company hemp + Nelles GmbH Co kG (epoxide content 2000-2220 mmol / kg; viscosity at 25 ⁰ C. 5.3 to 6.8 mPas) as starting materials for the preparation of the additives of the invention are used.

In principle, known etherification (in the case of q = 0) or esterification methods (in the case of q = 1) can be used to prepare the compounds according to the invention.

The preparation of the epoxy resins according to the invention can be carried out as described below:

a) with solvent

The commercially available epoxy resin prepared from bisphenol A and epichlorohydrin having an average molecular weight between M _n (number average) = 340 to M _n = 10,000 is dissolved in an organic solvent such as diethyl ether, chloroform, dichloromethane. At -5 to 35 ⁰ C, preferably at 0 to 10 ⁰ C, an organic base such as pyridine or a trialkylamine such as triethylamine are added to this solution. Thereafter, at the same temperature, the slow addition of an aryl or alkyl chloride dissolved in an organic solvent such as diethyl ether, chloroform or dichloromethane. The mixture is stirred for 0.5 to 24 hours, preferably for 1 to 6 hours. Thereafter, the precipitate formed is removed, for example by Abfütrieren. To remove salts, the organic phase is washed with water and the organic phase is preferably isolated in vacuo after suitable removal of water.

b) without solvent

Another possibility for the preparation of the epoxy resins according to the invention is the synthesis without solvent. The advantage of this method lies in the uncomplicated work-up and isolation of the product. For this purpose, the commercially available epoxy resin of bisphenol A and epichlorohydrin is heated with an aryl or alkyl anhydride at 80 to 200 ⁰ C, preferably to a temperature between the boiling temperature of the anhydride and the corresponding acid which is distilled off during the reaction. The reaction can be distilled off at the Track the amount of acid. After cooling, the product is ready for use without further workup.

The inventive method for producing the composition is carried out by adding the epoxy resin to the polycarbonate. The metered addition of the epoxy resin can be carried out during the work-up phase after the polymer synthesis or else subsequently, for example by subsequent admixing in a compounding extruder.

If the compounding is selected, the epoxy resins or mixtures thereof, in bulk or as a masterbatch of 5 to 20 wt .-% epoxy resin in a polycarbonate can be supplied to the compounding extruder. In the same processing step further additives may optionally be added in admixture with the epoxy resin or its masterbatch.

If the addition of the epoxy resin during the work-up phase after the polycarbonate synthesis is selected, we will proceed as described below.

The isolation of the polycarbonate from the solution can be carried out by evaporation of the solvent by means of temperature, vacuum or a heated towing gas. Other isolation methods are crystallization and precipitation. Happens the concentration of the polymer solution and possibly also the isolation of the polymer by distilling off the solvent, optionally by overheating and relaxation, so it is called a 'flash process' (see also "thermal separation process", VCH Verlagsanstalt 1988, p 114); If, instead, a heated carrier gas is sprayed together with the solution to be evaporated, this is referred to as "spray evaporation / spray drying" (described by way of example in Vauck, "Basic Operations in Chemical Process Engineering", Deutscher Verlag für Grundstoffindustrie 2000, 11th edition, page 690). All of these methods are described in the patent literature and textbooks and are familiar to those skilled in the art.

The removal of the solvent by temperature (distilling off) or the technically more effective flash process gives highly concentrated polymer melts. In the known

Flash method polymer solutions are repeatedly heated under slight pressure to temperatures above the boiling point under atmospheric pressure and this, with respect to the normal pressure, overheated solutions then in a vessel at a lower pressure, eg atmospheric pressure, relaxed. It may be advantageous to not let the Aufkonzentrationsstufen, or in other words the temperature levels of overbirth to be too large but rather to choose a two- to four-step process. From the resulting highly concentrated polymer melts, the residues of the solvent can either directly from the melt with Ausdampfextrudern (BE-A 866 991, EP-A 0 411 510, US-A 4,980,105, DE-A 33 32 065), thin-film evaporators (EP -A 0 267 025), falling film evaporators, extrudates or by friction compacting (EP-A 0 460 450), if appropriate also with the addition of an entrainer, such as nitrogen or carbon dioxide or using vacuum (EP-A 0 039 96, EP-A 0 256 003, US Pat. No. 4,423,207), alternatively also by subsequent crystallization (DE-A 34 29 960) and heating of the residues of the solvent in the solid phase (US Pat. No. 3,986,269, DE-A 20 53 876).

Granules are obtained either by direct spinning of the melt and subsequent granulation or by using Austragsextrudem, of which in air or liquid, preferably water, is spun off. If extruders are used, it is possible to add additives to the melt, upstream of this extruder, optionally with the use of static mixers or through side extruders in the extruder.

In this work-up procedure, the epoxy resin, optionally with further additives, can be added to the polycarbonate solution to be concentrated.

If the concentration of the polycarbonate solution from the polycarbonate production process by a Ausdampffextruder, as in the compounding process, or the addition of the resin, which was provided with other additives is carried out by means of masterbatches on a side extruder and are fed to the Ausdampffextruder.

The masterbatch used preferably contains thermoplastic polycarbonate and the oligomeric epoxy resin in an amount of 5 to 20 wt.% Based on the total weight of masterbatch, wherein preferably the thermoplastic polycarbonate of the masterbatch corresponds to the aromatic polycarbonate of the composition according to the invention. The masterbatch is used in a calculated amount, so that the total composition containing masterbatch and polycarbonate, which is in the form of its melt or as a solution, 0.1 to 5 wt .-%, preferably 1 to 3 wt .-% oligomeric epoxy resin based on contains the total composition.

The invention thus also relates to a method, wherein

in a first step, a masterbatch containing 80 to 95 wt .-% polycarbonate A and 5 to 20 wt .-% epoxy resin of the formula (I) is prepared, and

in a second step, 2 to 20% by weight of the masterbatch from the first step is mixed with 80 to 98% by weight of polycarbonate Al, wherein the polycarbonate A may be the same or different from the polycarbonate Al.

A further subject of the invention is also a process characterized in that an epoxy resin of the formula (I) is added to the polycarbonate solution to be concentrated during the work-up phase after the polycarbonate synthesis, wherein the weight ratio of polycarbonate to epoxy resin is 99.9: 0.1 to 95 : 5, preferably 99: 1 to 97: 3.

Other thermoplastic polycarbonates that can be used as a masterbatch are modified polycarbonates, such as e.g. Copolycarbonates. Preference is given to the use of bisphenol A polycarbonate in the masterbatch.

Should the oligomeric epoxy resin be incorporated into a polycarbonate solution, organic solvents such as dichloromethane or mixtures of dichloromethane and chlorobenzene are used for the aromatic polycarbonate. Preferred is dichloromethane as a solvent.

The compositions of the invention may also contain additional additives (component C). Such additives are flame retardants, mold release agents, antistatic agents, UV stabilizers, heat stabilizers, as are known for aromatic polycarbonates, in the amounts customary for polycarbonate. Preference is given to 0.1 to 1.5 wt .-% based on the polycarbonate used. Examples of such additives are mold release agents based on stearic acid and / or stearic alcohol, particularly preferably pentaerythritol stearate, trimethylolpropane tristearate, pentaerythritol distearate, stearyl stearate, and glycerol monostearate, and also heat stabilizers based on phosphanes and phosphites.

The compositions of the invention can be processed under normal conditions on the usual machines to any shaped articles such as plates, films, threads, lenses, discs, apparatus housings. The polycarbonates according to the invention can be processed on all systems suitable for thermoplastic molding compositions. The polycarbonates of the invention must be pre-dried as usual in polycarbonate. The polycarbonates of the invention can be molded in a wide processing latitude by all conventional methods such as injection molding and extrusion and injection blow molding. An overview of these methods is e.g. in Kunststoffhandbuch 1992, polycarbonates, polyacetals, polyesters, cellulose esters ed. W. Becker, p. 211 ff.

The present application also relates to the polycarbonates obtained by the process according to the invention and their use for the preparation of

Extrudates and shaped articles, in particular those for use in the transparent area, in particular in the field of optical applications, such as plates, web plates, glazings, Lenses, lamp covers or optical data storage (such as audio CD, CD-R (W), DVD, DVD-R (W), Mini Discs) in their various read only or rewritable possibly also repeatedly described embodiments.

The extrudates and shaped articles of the polymer according to the invention are likewise the subject of the present application.

Further applications are, for example, but without limiting the subject matter of the present invention:

1. Safety glasses, which are known in many areas of buildings, vehicles and

Aircraft are required, as well as shields of helmets.

2. Slides.

3. Blowing body (see US-A 2,964,794), for example 1 to 5 gallons of water bottles.

4. Translucent panels, such as solid sheets or in particular hollow panels, for example, for covering buildings such as stations, greenhouses and lighting systems.

5. Optical data storage, such as Audio CD's, CD-R (W) 's, DCD' s, DVD - R (W) 's, Minidiscs and Subsequent developments.

6. traffic light housing or traffic signs.

7. Foams with open or closed optionally printable surface.

8. Threads and wires (see DE-A 11 37 167).

9. Lighting applications, optionally using glass fibers for

Translucent applications.

10. Translucent settings with a content of barium sulfate and or titanium dioxide and or zirconium oxide or organic polymeric acrylate rubbers (EP-A 0 634 445, EP-A 0 269 324) for the production of translucent and light-scattering moldings.

11. Precision injection molded parts, such as holders, eg lens holders; Optionally polycarbonates with glass fibers and an optionally additional content of 1-10% by weight of molybdenum disulphide (based on the entire molding composition) are used here. 12. optical equipment parts, in particular lenses for photo and film cameras (DE-A 27 01 173).

13. Light transmission carrier, in particular optical fiber cable (EP-A 0 089 801) and lighting strips.

14. Electrical insulating materials for electrical conductors and for connector housings and connectors as well as capacitors.

15. Cellphone case.

16. Network interface devices.

17. Support materials for organic photoconductors.

18. Lights, Headlamps, Scatterers or Inner Lenses.

19. Medical applications such as oxygenators, dialyzers.

20. Food applications, such as bottles, dishes and chocolate molds.

21. Applications in the automotive sector, such as glazing or in the form of blends with ABS as a bumper.

22. Sporting goods like slalom poles, ski boot buckles.

23. Household items, such as kitchen sinks, sinks, mailboxes.

24. Housing, such as electrical distribution boxes.

25. Housing for electrical appliances such as toothbrushes, hair driers, coffee machines, machine tools, such as drilling, milling, planing machines and saws.

26. Washing machine portholes.

27. Goggles, sunglasses, corrective glasses or their lenses.

28. Lamp covers.

29. Packaging films.

30. Chip boxes, chip carriers, boxes for Si wafers.

31. Other applications such as stable or animal cage. Examples

Component A

Makrolon ^® 2808 (Bayer Material Science AG, Leverkusen, Germany), a linear polycarbonate based on bisphenol-A having a relative solution viscosity of 1.29, measured in CH ₂ Cl ₂ as solvent at 25 ° C and a concentration of 0.5 g of ( 100 ml).

Component Bl

Preparation of a tert-butylbenzoyl-modified epoxy resin

192 g of the BPA epoxy resin Epikote ^® 1001 (company hemp + new GmbH Co KG (Germany) (epoxide content 2000-2220 mmol / kg; viscosity at 25 ⁰ C. 5.3 to 6.8 mPas) are dissolved in 250 ml dichloromethane and cooled to 0 ° to 5 ° C. 55.7 g of triethylamine (0.55 mol) are added and then 108.2 g (0.55 mol) of tert-butylbenzoyl chloride are added dropwise at 0 ° to 5 ° C. The mixture is heated to room temperature The mixture is then refluxed for 2 hours, allowed to cool and filtered from the insoluble material, the organic phase is washed once with NaCl solution (half saturated), once with dilute HCl solution (2 molar) and finally with water The organic phase is dried over magnesium sulphate and concentrated under reduced pressure, the residue is dried under high vacuum (mbar) at 70 ^° C. 222.0 g of a yellow, glassy solid are obtained which are obtained according to Evaluation of the lH-NMR data formula (I) with

R 1 = CH ₃ , R ² = CH ₃ ,

R ³ = 4 t-Bu-C ₆ H ₄ - and q = 1

equivalent.

¹ H-NMR (400 MHz, CDCl ₃ ) δ = 8.0-7.90 (m), 7.50-7.40 (m), 7.15-7.05 (m), 6.85-6.75 (m), 5.79-6.60 (m), 4.35- 4.25 (m), 4.20-4.10 (m), 4.0-3.90 (m), 3.35-3.25 (m), 3.90-3.80 (m), 3.75-3.65 (m), 1.65-1.55 (m), 1.40-1.25 (m).

Component B2

Preparation of an acetoxy-modified epoxy resin in substance 200 g of the dried BPA epoxy resin Epikote ^® 1001 (company hemp + Nelles GmbH & Co KG (Germany) (epoxide content 2000-2220 mmol / kg; viscosity at 25 ° C from 5.3 to 6.8 mPas) are mixed with 49.6 g acetic anhydride and stirred for 24 h at 125 ° C, while the resulting acetic acid is distilled off After cooling, 220 g of a yellow solid are obtained, which according to evaluation of the 1H NMR data formula (I) with

R ¹ = Me, R ² = Me, R ³ = Me and q = i

equivalent.

¹ H-NMR (400 MHz, CDCl ₃ ) δ = 7.15-7.05 (m), 6.85-6.75 (m), 5.50-5.40 (m), 4.25-4.05 (m), 4.0- 3.90 (m), 3.35- 3.30 (m), 2.90-2.85 (m), 2.75-2.70 (m), 2.08 (s), 1.65-1.5 (m).

Example 1 (comparative example)

Makrolon 2808 is processed without additives.

The polycarbonate is passed through a compounding extruder (ZSK 32/3, screw kneader having a screw outer diameter of 32 mm) and granulated. The granules are injection molded at a mass temperature of 295 ° C and an extruder speed of 97 min ^"1 to plates in a size of 150 x 100 x 3.2 mm in optical quality.

Example 2

Production of a compound of A and Bl

792.0 g of polycarbonate (component A) are dissolved in 5.0 l of dichloromethane. 8 g of the tert-butylbenzoyl-modified epoxy resin prepared as described above are dissolved in 50 ml of dichloromethane and added to the polycarbonate solution. The mixture is concentrated and dried at 80 ⁰ C in a vacuum oven at 15 mbar for 24 hours. The resulting solid is ground and then passed through a compounding extruder (ZSK 32/3, 2 screw kneaders having a screw outer diameter of 32 mm) and granulated. Example 3

Incorporation of the acetyl-modified epoxy resin B2 in polycarbonate A

40 g of the acetyl-modified epoxy resin B2 are pulverized and mixed with 3960 g of polycarbonate on a Rhönradmischer.

This mixture is passed through a compounding extruder (ZSK 32/3, screw kneader having a screw outer diameter of 32 mm) and granulated. The granules are injection molded at a mass temperature of 295 ° C and an extruder speed of 97 min ^"1 to plates in a size of 150 x 100 x 3.2 mm in optical quality.

Testing the molding compounds

To determine the viscosity of the melt of the compound obtained, the zero viscosity is determined by means of a cone-plate viscometer (Physica UDS 200 rotational oscillation rheometer). It uses a cone-plate geometry. The cone angle is 2 ° and the cone diameter is 25 mm (MK 216). The samples are pressed at 230 ⁰ C with a hot press into thin films; Isothermal frequency spectra were recorded at the specified temperatures.

The determination of the average molecular weight is carried out via GPC at room temperature calibrated on BPA-PC.

The glass transition temperature is measured in the heat flow differential calorimeter (Mettler) at 20 K / min in standard aluminum crucibles over a temperature range of 0 ⁰ C to 250 ⁰ C in the 1st and 0 to 300 ⁰ C in the 2nd heating. The value determined in the 2nd heating process is indicated.

The thermoplastic melt flow rate (MVR) (melt volume flow rate) is determined according to ISO 1133.

The colorimetric evaluation is carried out in accordance with ASTM E 308, the yellowness index is determined according to ASTM E 313, the haze is determined according to ASTM D 1003 and the light transmission is specified for illuminant D65, 10 ° observer (identical to standard color value Y).

The properties of the mixture are summarized in Table 1. Table 1: Composition and properties of the molding compositions

Component (% by weight) 1 2 3

A 100 99 99

Bl - 1 -

B2 - - 1

Zero viscosity 270 ⁰ C [Pa s] 1480 980 1010

MVR [cmVlO min] 8.9 12.3

Transmission [%] 89.7 89.0

Haze [%] 0.2 0.9

YI 1.9 2.2

Tg (DSC) [ ⁰ C] 148 146 145

Mw [g / mol] 28200 27700 28200

Compositions 2 and 3 show the invention compared to the unmodified Makrolon ^® 2808 (component A) a markedly decreased zero shear viscosity. In addition, composition 2 also shows an advantageously higher MVR value. The optical properties like the transmission of the plates, the yellowness index (yellowness value) and. the haze value (cloudiness) and the glass transition temperature and the average molecular weight of the molding materials, however, are still comparable to a pure Makrolon ^® 2808 (component A) level.

Claims

claims

1. Epoxy resins of the formula (T)

(I) woπn

R, R independently of one another H, Ci-Ci ₂ alkyl, phenyl or benzyl, or together form a cyclic C ₅ -C signify _2-alkyl radical, preferably H or methyl or together are the cyclohexyl radical,

R ^{3 is} an optionally substituted aryl, benzyl, optionally branched C ₁ -C ₈ -alkyl or cyclic C ₅ -C 12 -alkyl radical,

n stands for a numerical average value of 0.5 - 20, stands and

q is 0 or 1.

2. Epoxy resins according to claim 1, wherein q = 1.

3. Containing compositions

A) 95 to 99.9 wt .-% polycarbonate and

B) 0.1 to 5 wt .-% epoxy resin of the formula (I) according to claim 1.

4. Compositions according to claim 3 containing

A) 97 to 99 wt .-% polycarbonate and

B) 1 to 3 wt .-% epoxy resin of the formula (I).

5. Compositions according to claim 3 additionally containing at least one additive selected from the group of flame retardants, mold release agents, antistatic agents, UV stabilizers and heat stabilizers.

6. A process for the preparation of the compositions according to claim 3, wherein the components A and B are mixed and extruded in a compounding extruder.

7. The method according to claim 6, characterized in that

in a second step, 2 to 20% by weight of the masterbatch from the first step is mixed with 80 to 98% by weight of polycarbonate Al,

wherein the polycarbonate A may be the same or different from the polycarbonate Al.

8. A process for the preparation of the compositions according to claim 3, characterized in that an epoxy resin of the formula (I) is added to the polycarbonate solution to be narrowed during the work-up phase after the polycarbonate synthesis, wherein the weight ratio of polycarbonate to epoxy resin 99.9: 0.1 to 95: 5.

9. Use of the compositions according to any one of claims 3 to 5 for the production of extrudates and / or moldings.

10. Use of the composition according to any one of claims 3 to 5 for the production of moldings for optical applications.

11. Shaped bodies and extrudates, comprising a composition according to any one of claims 3 to 5.

12. plates, optical data storage, lenses, headlamps and scattered light panes comprising a composition according to any one of claims 3 to 5.