Method for preparing polysiloxane-polycarbonate block copolymers

Abstract

The present invention relates to a continuous process for preparing polysiloxane-polycarbonate block copolymers by polycondensation, characterized by the use of at least one thin-film evaporator, said at least one thin-film evaporator having at its periphery at least two wiper blade elements rotating in the at least one thin-film evaporator. In the process according to the invention, an oligocarbonate and a hydroxyaryl-terminated polysiloxane are reacted to form a polysiloxane-polycarbonate block copolymer, also known as SiCoPC. This process is also characterized by the observance of certain process parameters during the reaction of the oligocarbonate and the hydroxyaryl-terminated polysiloxane using at least one thin-film evaporator. The polysiloxane-polycarbonate block copolymers prepared by the method according to the invention are characterized by a small volume fraction of large polysiloxane domains with a simultaneous narrow size distribution of the polysiloxane domains, good mechanical properties, in particular robust fracture behavior in the notch impact test according to ISO 7391 / ISO 180A, good processability, e.g. in injection molding or extrusion, and good flowability.

Description

[Technical field]

[0001] The present invention relates to a continuous process for the preparation of polysiloxane-polycarbonate block copolymers by polycondensation, characterized by the use of at least one thin-film evaporator, which at its periphery is provided with at least two wiper blade elements rotating within the at least one thin-film evaporator. In the process according to the invention, an oligocarbonate is reacted with a hydroxyaryl-terminated polysiloxane to obtain a polysiloxane-polycarbonate block copolymer, also known as SiCoPC. This process is further characterized in that in the reaction of the oligocarbonate with the hydroxyaryl-terminated polysiloxane using at least one thin-film evaporator, certain process parameters are observed. The polysiloxane-polycarbonate block copolymers produced by the method according to the invention are characterized by a low volume fraction of large polysiloxane domains with a simultaneous narrow size distribution of the polysiloxane domains, good mechanical properties, in particular robust fracture behavior in notched impact tests according to ISO 7391 / ISO 180A, good processability, e.g. in injection molding or extrusion, and good flowability.

[0002] In the context of the present invention, a small volume fraction of large polysiloxane domains and a narrow size distribution of the polysiloxane domains are achieved when, in a polysiloxane-polycarbonate block copolymer, the volume fraction of polysiloxane domains having a diameter of more than 100 nm is less than 70%, the volume fraction of polysiloxane domains having a diameter of more than 200 nm is less than 30%, and the volume fraction of polysiloxane domains having a diameter of more than 500 nm is less than 0.1%, measured based on the total volume of the polysiloxane domains. Such a volume fraction of large polysiloxane domains and at the same time such a narrow size distribution of the polysiloxane domains are also referred to below as "fine polysiloxane domain size distribution".

[0003] Preferably, in the polysiloxane-polycarbonate block copolymer, the volume fraction of polysiloxane domains having a diameter of more than 100 nm is less than 60%, while the volume fraction of polysiloxane domains having a diameter of more than 200 nm is less than 20%, and while the volume fraction of polysiloxane domains having a diameter of more than 500 nm is less than 0.1%, measured based on the total volume of the polysiloxane domains.

[0004] Particularly preferably, in the polysiloxane-polycarbonate block copolymer, the volume fraction of polysiloxane domains having a diameter of more than 100 nm is less than 50%, while the volume fraction of polysiloxane domains having a diameter of more than 200 nm is less than 10%, and while the volume fraction of polysiloxane domains having a diameter of more than 500 nm is less than 0.1%, measured based on the total volume of the polysiloxane domains.

[0005] Very particularly preferably, in the polysiloxane-polycarbonate block copolymer, the volume fraction of polysiloxane domains having a diameter of more than 100 nm, measured based on the total volume of the polysiloxane domains, is less than 40%, while the volume fraction of polysiloxane domains having a diameter of more than 200 nm is less than 1% and while the volume fraction of polysiloxane domains having a diameter of more than 500 nm is less than 0.1%.

[0006] To determine the size of the polysiloxane domains, polymer samples are cut at low temperatures and subjected to scanning electron microscopy examination as described in more detail below. In the context of the present invention, the diameter of a polysiloxane domain is understood to mean the diameter of the equivalent circular area of ​​the cross section of the polysiloxane domain as seen by cutting. [Background technology]

[0007] It is known that polysiloxane-polycarbonate block copolymers show good properties in terms of low-temperature impact strength / low-temperature notched impact strength, chemical resistance and outdoor weathering resistance, as well as aging properties and fire resistance.Polysiloxane-polycarbonate block copolymers are superior in these properties to conventional polycarbonates, i.e. standard polycarbonates.In the context of the present invention, conventional polycarbonates or standard polycarbonates are understood to mean homopolycarbonates based on bisphenol-A.

[0008] In the context of the present invention, the relative solution viscosity is determined in each case in dichloromethane at a concentration of 5 g / l at 25° C. using an Ubbelohde viscometer.

[0009] According to the prior art, polysiloxane-polycarbonate block copolymers are industrially prepared starting from bisphenol monomers and polydiorganosiloxanes by the so-called phase interface process using phosgene. The preparation of polysiloxane-polycarbonate block copolymers starting from bisphenol monomers and polydiorganosiloxanes by the so-called melt transesterification process using diphenyl carbonate is also known from the prior art.

[0010] In the case of the phase interface process, the production of polysiloxane-polycarbonate block copolymers by the prior art has the disadvantage of requiring starting materials with special handling requirements, such as phosgene. Furthermore, when an industrial plant configured to produce standard polycarbonate is used to produce polysiloxane-polycarbonate block copolymers in the melt transesterification process, the residence time of the reaction mixture for producing polysiloxane-polycarbonate block copolymers at high temperatures in the reactor becomes very long. This significantly increases the thermal stress on the polysiloxane-polycarbonate block copolymer, adversely affecting the properties of the polysiloxane-polycarbonate block copolymer.

[0011] The preparation of polysiloxane-polycarbonate block copolymers by the phase interface process is known from the literature and is described, for example, in US Pat. No. 5,399,621 or US Pat. No. 5,499,633.

[0012] US Pat. No. 5,399,633 describes the preparation of polysiloxane-polycarbonate block copolymers by melt transesterification of carbonate-terminated polysiloxanes with bisphenols, particularly bisphenol-A, and diaryl carbonates, particularly diphenyl carbonate, and US Pat. No. 5,399,633 also details the disadvantages of the phase interface process: Due to the high incompatibility of polysiloxanes with bisphenols and diaryl carbonates, it is not possible without great difficulty to obtain a fine polysiloxane domain size distribution when incorporating polysiloxanes into a polycarbonate matrix in the melt transesterification process.

[0013] The preparation of polysiloxane-polycarbonate block copolymers in a melt transesterification process is known from the literature and is described, for example, in US Pat. No. 5,399,623 or US Pat. No. 5,499,636. The reaction times disclosed therein are not economically viable for large-scale industrial processes. These documents do not contain any practical teachings on how to reduce the reaction time and thus the residence time.

[0014] Patent Document 5 also discloses that a polysiloxane domain size as small as 15 nm can be achieved, but the polysiloxane domain size distribution that is evident only from the drawing is not useful for current demands. Furthermore, it does not disclose how a fine polysiloxane domain size distribution can be obtained.

[0015] A broad, i.e. not fine, polysiloxane domain size distribution in polysiloxane-polycarbonate block copolymers adversely affects the aesthetic appearance and / or mechanical properties of molded articles made from polysiloxane-polycarbonate block copolymers. Large polysiloxane domains can lead to demixing of the polysiloxane phase from the polycarbonate phase in polysiloxane-polycarbonate block copolymers, which can manifest as a non-uniform surface structure of the polysiloxane-polycarbonate block copolymers, causing flow lines and striping, as well as undesirable optical interference, in injection molded molded articles made from polysiloxane-polycarbonate block copolymers. The aesthetic appearance of such molded articles is unsatisfactory, and such molded articles are no longer uniformly colorable, and therefore are not suitable for many commercial applications. Such polysiloxane-polycarbonate block copolymers are more difficult to process in injection molding because the large polysiloxane domains are susceptible to shear and can cause delamination in molded articles produced from such polysiloxane-polycarbonate block copolymers by injection molding, and as a result, often only very low injection speeds can be used, which is undesirable because of the long cycle times.

[0016] Furthermore, neither Patent Document 4 nor Patent Document 5 teaches any method by which the flowability of the resulting polysiloxane-polycarbonate block copolymer can be adjusted.

[0017] The skilled person knows what is understood by polysiloxane domains, which can be found for example in the publications "Polysiloxane Domains" (pp. 111-115, 2002) and "Polysiloxane Domains" (pp. 111-115, 2002).

[0018] It is known in principle that additives can be used to reduce the volume fraction of large polysiloxane domains in polysiloxane-polycarbonate block copolymers. The addition of compatibilizers is described, for example, in US Pat. No. 5,399,433 and US Pat. No. 5,499,433. However, the compatibilizers described in US Pat. No. 5,399,433 and US Pat. No. 5,499,433 are very expensive and significantly increase the raw material cost of polysiloxane-polycarbonate block copolymers. Other compatibilizers are also disadvantageous because they are very expensive or decompose due to the high temperatures in the melt transesterification process or result in products with insufficient melt stability and cannot be used. [Prior art documents] [Patent documents]

[0019] [Patent Document 1] U.S. Patent No. 3,189,662 [Patent Document 2] European Patent Application Publication No. 0122535 [Patent Document 3] U.S. Patent No. 5,504,177 [Patent Document 4] European Patent No. 0864599 [Patent Document 5] European Patent Application Publication No. 0770636 [Patent Document 6] European Patent Application Publication No. 3719077 [Patent Document 7] International Publication No. 2020201178 [Non-patent literature]

[0020] [Non-Patent Document 1] "Structure to Property Relationship in Polycarbonate / Polydimethylsiloxane Copolymers", Matthew R. Pixton, published in "Associacao Brasileira de Polimeros, Sao Paulo, SP (Brazil); [vp.]; 2005; 2 p; 8. Brazilian congress on polymers; 8. congresso brasileiro de polimeros; Aguas de Lindoia, SP (Brazil); 6-10 Nov 2005" [Non-Patent Document 2] "Structure to Property Relationship in Polycarbonate / Polydimethylsiloxane Copolymers", Matthew R. Pixton, published in "ANTEC 2006, Annual Technical Conference, Charlotte, North Carolina, May 7-11, 2006, Conference Proceedings, pages 2655-2659" Summary of the Invention [Problem to be solved by the invention]

[0021] Starting from the above-mentioned prior art, it was therefore an object to overcome at least one of the disadvantages of the prior art. In particular, the object of the present invention was to provide a method for producing polysiloxane-polycarbonate block copolymers, which allows the production of polysiloxane-polycarbonate block copolymers with good flowability and at the same time a fine polysiloxane domain size distribution. Good flowability is advantageous when further processing the polysiloxane-polycarbonate block copolymers in injection molding, since it allows the production of parts with complex shapes and thin wall thicknesses. A further object of the present invention was to configure the method in such a way that it allows short residence times, is cost-effective and avoids starting materials with special handling requirements such as phosgene. In this context, residence time is understood to mean the time required for the production of the desired polysiloxane-polycarbonate block copolymers with the desired relative solution viscosity by incorporation of the polysiloxane component, and in the method according to the present invention described below, the residence time corresponds to the reaction time.

[0022] The process shall be capable of continuous operation.In addition, a further object of the present invention was to make it possible to avoid expensive compatibilizers.

[0023] In the polysiloxane-polycarbonate block copolymer, the volume fraction of polysiloxane domains having a diameter greater than 100 nm is less than 70%, while the volume fraction of polysiloxane domains having a diameter greater than 200 nm is less than 30%, and while the volume fraction of polysiloxane domains having a diameter greater than 500 nm is less than 0.1%, measured based on the total volume of the polysiloxane domains.

[0024] Preferably, in the polysiloxane-polycarbonate block copolymer, the volume fraction of polysiloxane domains having a diameter of more than 100 nm is less than 60%, while the volume fraction of polysiloxane domains having a diameter of more than 200 nm is less than 20%, and while the volume fraction of polysiloxane domains having a diameter of more than 500 nm is less than 0.1%, measured based on the total volume of the polysiloxane domains.

[0025] Particularly preferably, in the polysiloxane-polycarbonate block copolymer, the volume fraction of polysiloxane domains having a diameter of more than 100 nm is less than 50%, while the volume fraction of polysiloxane domains having a diameter of more than 200 nm is less than 10%, and while the volume fraction of polysiloxane domains having a diameter of more than 500 nm is less than 0.1%, measured based on the total volume of the polysiloxane domains.

[0026] Very particularly preferably, in the polysiloxane-polycarbonate block copolymer, the volume fraction of polysiloxane domains having a diameter of more than 100 nm, measured based on the total volume of the polysiloxane domains, is less than 40%, while the volume fraction of polysiloxane domains having a diameter of more than 200 nm is less than 1% and while the volume fraction of polysiloxane domains having a diameter of more than 500 nm is less than 0.1%.

[0027] At the same time, the flowability must remain high. However, the flowability must not exceed values ​​that would result in a deterioration of the mechanical properties of the molded articles produced from the polysiloxane-polycarbonate block copolymers produced by the process according to the invention, in particular by injection molding. The relative solution viscosity can be regarded as a measure of the flowability. For this purpose, the relative solution viscosity of the polysiloxane-polycarbonate block copolymers produced by the process according to the invention with a polysiloxane content of 2% by weight to 15% by weight, preferably 3% by weight to 10% by weight, particularly preferably 4% by weight to 8% by weight, should preferably be 1.24 to 1.38, preferably 1.26 to 1.36, particularly preferably 1.27 to 1.35. The polysiloxane-polycarbonate block copolymers produced according to the invention are easily processable with a relative solution viscosity in this range, for example by injection molding or extrusion.

[0028] Very particularly preferably, the relative solution viscosity of the polysiloxane-polycarbonate block copolymers produced by the process according to the invention having a polysiloxane content of 4.5% to 5.5% by weight is 1.24 to 1.34, preferably 1.26 to 1.33, particularly preferably 1.27 to 1.32.

[0029] Again, in the polysiloxane-polycarbonate block copolymer, the volume fraction of polysiloxane domains greater than 100 nm in diameter is less than 70%, while the volume fraction of polysiloxane domains greater than 200 nm in diameter is less than 30%, and while the volume fraction of polysiloxane domains greater than 500 nm in diameter is less than 0.1%, measured based on the total volume of the polysiloxane domains.

[0030] Again, preferably, in the polysiloxane-polycarbonate block copolymer, the volume fraction of polysiloxane domains having a diameter of more than 100 nm is less than 60%, while the volume fraction of polysiloxane domains having a diameter of more than 200 nm is less than 20%, and while the volume fraction of polysiloxane domains having a diameter of more than 500 nm is less than 0.1%, measured based on the total volume of the polysiloxane domains.

[0031] Here too, it is particularly preferred that in the polysiloxane-polycarbonate block copolymer, the volume fraction of polysiloxane domains having a diameter of more than 100 nm is less than 50%, while at the same time the volume fraction of polysiloxane domains having a diameter of more than 200 nm is less than 10%, and at the same time the volume fraction of polysiloxane domains having a diameter of more than 500 nm is less than 0.1%, measured based on the total volume of the polysiloxane domains.

[0032] Here too, it is very particularly preferable that in the polysiloxane-polycarbonate block copolymer, the volume fraction of polysiloxane domains having a diameter of more than 100 nm, measured based on the total volume of the polysiloxane domains, is less than 40%, while the volume fraction of polysiloxane domains having a diameter of more than 200 nm is less than 1% and while the volume fraction of polysiloxane domains having a diameter of more than 500 nm is less than 0.1%.

[0033] The polysiloxane-polycarbonate block copolymers prepared according to the invention are particularly easily processable, for example by injection molding or extrusion, at relative solution viscosities in this very particularly preferred range.

[0034] This is particularly true when the polysiloxane-polycarbonate block copolymers produced by the method according to the invention have a polysiloxane content of 4.5% to 5.5% by weight.

[0035] It is further particularly preferred that the polysiloxane-polycarbonate block copolymers produced by the process according to the invention exhibit robust fracture behavior down to -60°C in the notched impact test according to ISO 7391 / ISO 180A, even at low polysiloxane contents. [Means for solving the problem]

[0036] These objects are achieved by a method for producing polysiloxane-polycarbonate block copolymers, which method is characterized by the use of exactly one thin-film evaporator or alternatively by the use of two or more thin-film evaporators arranged in series, in each case maintaining specific process conditions.

[0037] In the context of the present invention, a thin-film evaporator is understood to mean a vertically arranged device with an axially extending, rotationally symmetric, preferably cylindrical, reaction chamber, at the upper end of which a reaction mixture consisting of a polymer melt in the form of a molten dispersion and liquid polysiloxane is fed, and at the lower end of which said mixture is discharged from the device in the form of a further reacted reaction mixture, and which is fitted with a rotor with at least two wiper blade elements, generally three, four or more wiper blade elements, on its periphery. Each wiper blade element has an outer edge, which extends in the axial direction and is oriented towards the inner surface area of ​​the axially extending, rotationally symmetric reaction chamber, ensuring a constant surface renewal of the reaction mixture by spreading the reaction mixture over the inner peripheral edge of the axially extending, rotationally symmetric reaction chamber. The inner surface area of ​​the reaction chamber has the same geometric shape as the reaction chamber, i.e. a cylindrical reaction chamber also has a cylindrical inner surface area. The wiper blade elements can therefore be arranged parallel to the axial direction or at an action angle to the longitudinal axis.Thin-film evaporators which are in principle suitable for carrying out the process according to the invention are described, for example, in EP 3318311, EP 1792643, DE 19535817, DE 102012103749, DE 2011493 or GDR 226778 or in the publication (1) "Platzer (ed.): Polymerization Kinetics and Technology, Advances in Chemistry; American Chemical Society: Washington, DC, 1973, pages 51 to 67: Fritz Widmer: Behaviour of Viscous Polymers during Solvent Stripping or Reaction in an Agitated Thin Film; Swiss Federal Institute of Technology, Zurich, Switzerland", where thin-film evaporators as disclosed in DE-A-19535817, GDR-A-226778 or EP-A-3318311 or as disclosed in FIG. 7, page 58 and FIG. 9, page 60 of (1) are particularly suitable for carrying out the method according to the invention. Further options for constructing thin-film evaporators are disclosed in the article "Scaleup of Agitated Thin-film Evaporators", William B. Glover, reprinted from Chemical Engineering, April 2004.

[0038] In the polycondensation of oligocarbonates with polysiloxanes to obtain polysiloxane-polycarbonate block copolymers, it is important to spread the melt of the reaction mixture over the inner surface area of ​​the reaction chamber of the thin film evaporator, since the hydroxyl compounds formed during the polycondensation, generally phenols, must be effectively removed by evaporation, thus requiring constant surface renewal. In such operations, which result in a large surface area in addition to good surface renewal, reactors such as rotating disk reactors or other high-viscosity reactors are generally required, the residence time of the reaction mixture in the reactor being between 60 and 180 minutes. The use of rotating disk reactors, in particular, in polycondensations to produce standard polycarbonates is described in the prior art, for example in US Patent Application Publication No. 2002188091 or DE Patent Application Publication No. 10142735.

[0039] It was therefore quite surprising that rotating disk reactors or other high viscosity reactors are not suitable for the production of polysiloxane-polycarbonate block copolymers having a good combination of narrow polysiloxane domain size distribution and good flowability, because the use of expensive compatibilizers does not ensure a sufficiently fine size distribution of the polysiloxane domains.

[0040] (1) This object is particularly achieved in a first embodiment of the invention by: 1. A method for the continuous production of polysiloxane-polycarbonate block copolymers using exactly one thin film evaporator, comprising: The method comprises the following method steps: (1) providing a reaction mixture containing a hydroxyaryl-terminated polysiloxane having a relative solution viscosity of 1.08 to 1.22 and containing an oligocarbonate having an OH group content of 1000 ppm to 2500 ppm; (2) a process step of introducing the reaction mixture provided in step (1) containing the oligocarbonate and the hydroxyaryl-terminated polysiloxane into exactly one thin film evaporator; wherein the thin film evaporator comprises exactly one reaction chamber having exactly one rotor having at least two wiper blade elements on a periphery thereof, the exactly one rotor rotating within the thin film evaporator, each wiper blade element having an outer periphery; (3) reacting the reaction mixture from step (2) to obtain a polysiloxane-polycarbonate block copolymer; wherein the reaction mixture is conveyed from an inlet of a thin film evaporator to an outlet of the thin film evaporator; (4) discharging the polysiloxane-polycarbonate block copolymer obtained in step (3) from the thin film evaporator; It is characterized by: In step (3), exactly one thin-film evaporator is subjected to the following process conditions: (3.a) a shear rate between the outer edge of at least two peripheral rotating wiper blade elements and the axially extending rotationally symmetric inner surface area of ​​the reaction chamber of the thin film evaporator is 500 1 / s to 5000 1 / s; (3.b) The pressure in the reaction chamber of the thin-film evaporator is 0.01 mbara to 10 mbara; (3.c) the temperature of the reaction mixture in the reaction chamber is between 280°C and 370°C; (3.d) The surface renewal frequency of the reaction mixture is 10 Hz to 50 Hz; It is observed that,

[0041] (2) Alternatively, this object is achieved in a second embodiment of the invention by: A method for continuously producing a polysiloxane-polycarbonate block copolymer using a plurality of thin film evaporators arranged in series, the number of which is at least two, The method comprises the following method steps: (1) providing a reaction mixture containing a hydroxyaryl-terminated polysiloxane having a relative solution viscosity of 1.08 to 1.22 and containing an oligocarbonate having an OH group content of 1000 ppm to 2500 ppm; (2) a process step of introducing the reaction mixture provided in step (1) containing the oligocarbonate and the hydroxyaryl-terminated polysiloxane into a first of at least two thin film evaporators arranged in series; wherein each of the at least two thin film evaporators comprises exactly one reaction chamber having exactly one rotor, each rotor having at least two wiper blade elements on its periphery, exactly one rotor in each thin film evaporator rotating, each wiper blade element having an outer periphery; (3) reacting the reaction mixture from step (2) to obtain a polysiloxane-polycarbonate block copolymer; wherein the reaction mixture is conveyed from an inlet of a first thin film evaporator of the at least two thin film evaporators arranged in series to an outlet of a last thin film evaporator of the at least two thin film evaporators arranged in series; (4) a process step of discharging the polysiloxane-polycarbonate block copolymer obtained in step (3) from the last thin film evaporator; It is characterized by: In step (3), the last evaporator of at least two thin-film evaporators arranged in series is subjected to the following process conditions: (3.a) a shear rate between the outer edge of at least two peripheral rotating wiper blade elements and the axially extending rotationally symmetric inner surface area of ​​the reaction chamber of the thin film evaporator is 500 1 / s to 5000 1 / s; (3.b) The pressure in the reaction chamber of the thin-film evaporator is 0.01 mbara to 10 mbara; (3.c) the temperature of the reaction mixture in the reaction chamber is 280°C to 370°C; (3.d) Surface renewal frequency of the reaction mixture: 10 Hz to 50 Hz; It is observed that,

[0042] In both the first embodiment of the method according to the invention and the second embodiment of the method according to the invention the following applies:

[0043] The pressure measurement can be carried out, for example, using a WIKA IS-3 pressure sensor or an Endress+Hauser Cerabar pressure sensor, however, it is also possible to use other suitable prior art pressure sensors known to those skilled in the art.

[0044] The temperature of the reaction mixture can be measured, for example, by means of an L-type thermocouple or a Pt100 resistance thermometer, the measuring tip of which is immersed sufficiently deep in the reaction mixture. However, it is also possible to use other suitable prior art temperature measuring means known to the skilled person. The temperature measurement inside the thin film evaporator can be carried out in a manner known from EP 3 318 311 A1.

[0045] The rotational speed can be preferably measured via a conventional initiator / pulser on the rotor in a manner known to those skilled in the art. However, it is also possible to use other suitable conventional tachometers known to those skilled in the art. The surface renewal frequency is obtained by multiplying the rotational speed by the number of peripheral wiper blade elements.

[0046] The shear rate is calculated by dividing the rotational speed of the rotor, which is determined from the inner circumference of the processing chamber and the speed of the rotor, by the spacing between the tip of the rotor and the housing wall.

[0047] In both the first embodiment of the process according to the present invention and the second embodiment of the process according to the present invention, the residence time of the reaction mixture in step (3) is preferably 2 minutes to 12 minutes, particularly preferably 3 minutes to 10 minutes.

[0048] In both the first embodiment of the process according to the invention and the second embodiment of the process according to the invention, all of the polysiloxane-polycarbonate block copolymers produced thereby are obtainable with such short residence times.

[0049] In a second embodiment of the present invention, the number of thin film evaporators arranged in series can be two or three or four or more thin film evaporators arranged in series.

[0050] In the second embodiment of the invention, it is preferred according to the invention that the number of thin-film evaporators arranged in series is exactly two.

[0051] The thin film evaporator that can be used according to the invention is characterized in that it comprises at least two wiper blade elements at its periphery that can rotate in the thin film evaporator. It is preferred that the thin film evaporator comprises three or more wiper blade elements at its periphery that can rotate in the thin film evaporator, in particular three, four or more wiper blade elements.

[0052] At least a part of the axially extending rotationally symmetric inner surface area of ​​the axially extending rotationally symmetric reaction chamber of the thin film evaporator also serves as a heat transfer area. Heat may be supplied to the reaction chamber via the heat transfer area or heat may be removed from the reaction chamber via the heat transfer area. In the thin film evaporator, the proportion of the axially extending rotationally symmetric inner surface area of ​​the axially extending rotationally symmetric reaction chamber to which the reaction mixture is applied that serves as a heat transfer area is between 90% and 100%, preferably 100%.

[0053] In both the first embodiment of the process according to the invention and the second embodiment of the process according to the invention, the temperature of the heat transfer zone is between 280° C. and 340° C., and any heat generated during the reaction of the reaction mixture in process step (3), for example by shearing of the reaction mixture, can be removed via the heat transfer zone. The heat transfer zone may have a temperature profile or may have two or more temperature zones, or both.

[0054] In the context of the present invention, the term "mbara" denotes the unit for reporting absolute pressure in mbar, "mbar absolute."

[0055] In step (1), the reaction mixture is preferably provided by preparing an oligocarbonate by polycondensation and mixing it with a previously prepared ex situ hydroxyaryl-terminated polysiloxane, however, it is also possible to plasticize a previously prepared ex situ reaction mixture and provide it as a melt.

[0056] In both the first embodiment of the process according to the invention and the second embodiment of the process according to the invention, it applies that the reaction mixture in process step (1) and the polysiloxane-polycarbonate block copolymer obtained on discharge from the last thin-film evaporator of several thin-film evaporators arranged in series, and the reaction mixture formed intermediately from the reaction mixture in process step (1) in the reaction to obtain the polysiloxane-polycarbonate block copolymer, are in molten form. In the first embodiment of the process according to the invention, the only thin-film evaporator can be considered as the last thin-film evaporator.

[0057] Both the polysiloxane-polycarbonate block copolymers obtained according to the first embodiment of the process according to the invention and the polysiloxane-polycarbonate block copolymers obtained according to the second embodiment of the process according to the invention preferably have the following characteristics: The polysiloxane domains have a fine size distribution, i.e. In the polysiloxane-polycarbonate block copolymer, the volume fraction of polysiloxane domains having a diameter of more than 100 nm, measured based on the total volume of the polysiloxane domains, is less than 70%, while the volume fraction of polysiloxane domains having a diameter of more than 200 nm is less than 30%, while the volume fraction of polysiloxane domains having a diameter of more than 500 nm is less than 0.1%, and while the relative solution viscosity is 1.38 to 1.24, preferably 1.36 to 1.26, particularly preferably 1.35 to 1.27, which is also referred to as the desired relative solution viscosity. Preferably, in the polysiloxane-polycarbonate block copolymer, the volume fraction of polysiloxane domains having a diameter of more than 100 nm, measured based on the total volume of the polysiloxane domains, is less than 60%, and at the same time the volume fraction of polysiloxane domains having a diameter of more than 200 nm is less than 20%, and at the same time the volume fraction of polysiloxane domains having a diameter of more than 500 nm is less than 0.1%, again with a relative solution viscosity of 1.36 to 1.24, preferably 1.36 to 1.26, particularly preferably 1.35 to 1.27, again this relative solution viscosity being referred to as the desired relative solution viscosity. Particularly preferably, in the polysiloxane-polycarbonate block copolymer, the volume fraction of polysiloxane domains having a diameter of more than 100 nm, measured based on the total volume of the polysiloxane domains, is less than 50%, and at the same time the volume fraction of polysiloxane domains having a diameter of more than 200 nm is less than 10%, and at the same time the volume fraction of polysiloxane domains having a diameter of more than 500 nm is less than 0.1%, again with a relative solution viscosity of 1.38 to 1.24, preferably 1.36 to 1.26, particularly preferably 1.35 to 1.27, which is also referred to as the desired relative solution viscosity. Very particularly preferably, in the polysiloxane-polycarbonate block copolymer, the volume fraction of polysiloxane domains having a diameter of more than 100 nm, measured based on the total volume of the polysiloxane domains, is less than 40%, and at the same time the volume fraction of polysiloxane domains having a diameter of more than 200 nm is less than 1% and at the same time the volume fraction of polysiloxane domains having a diameter of more than 500 nm is less than 0.1%, again with a relative solution viscosity of 1.38 to 1.24, preferably 1.36 to 1.26, particularly preferably 1.352 to 1.27, again this relative solution viscosity being referred to as the desired relative solution viscosity.

[0058] Both the polysiloxane-polycarbonate block copolymers obtained according to the first embodiment of the method according to the invention and the polysiloxane-polycarbonate block copolymers obtained according to the second embodiment of the method according to the invention are superior to prior art polysiloxane-polycarbonate block copolymers having a polysiloxane content of 2% to 15% by weight, as well as to prior art polysiloxane-polycarbonate block copolymers having a polysiloxane content of 3% to 10% by weight, as well as to prior art polysiloxane-polycarbonate block copolymers having a polysiloxane content of 4% to 8% by weight, where the polysiloxane content refers to the total weight of the polysiloxane-polycarbonate block copolymer. This is especially true when comparing the polysiloxane-polycarbonate block copolymers produced according to the invention with those produced by the melt transesterification process.

[0059] However, the polysiloxane-polycarbonate block copolymers prepared by the process according to the invention have a polysiloxane content of 4.5% by weight to 5.5% by weight, and they have a relative solution viscosity of 1.24 to 1.34, preferably 1.26 to 1.33, particularly preferably 1.27 to 1.32, where again the following applies:

[0060] The polysiloxane domains have a fine size distribution, i.e. In the polysiloxane-polycarbonate block copolymer, the volume fraction of polysiloxane domains greater than 100 nm in diameter is less than 70%, while the volume fraction of polysiloxane domains greater than 200 nm in diameter is less than 30%, and while the volume fraction of polysiloxane domains greater than 500 nm in diameter is less than 0.1%, measured based on the total volume of the polysiloxane domains.

[0061] Preferably, in the polysiloxane-polycarbonate block copolymer, the volume fraction of polysiloxane domains having a diameter of more than 100 nm is less than 60%, while the volume fraction of polysiloxane domains having a diameter of more than 200 nm is less than 20%, and while the volume fraction of polysiloxane domains having a diameter of more than 500 nm is less than 0.1%, measured based on the total volume of the polysiloxane domains.

[0062] Particularly preferably, in the polysiloxane-polycarbonate block copolymer, the volume fraction of polysiloxane domains having a diameter of more than 100 nm is less than 50%, while the volume fraction of polysiloxane domains having a diameter of more than 200 nm is less than 10%, and while the volume fraction of polysiloxane domains having a diameter of more than 500 nm is less than 0.1%, measured based on the total volume of the polysiloxane domains.

[0063] Very particularly preferably, in the polysiloxane-polycarbonate block copolymer, the volume fraction of polysiloxane domains having a diameter of more than 100 nm, measured based on the total volume of the polysiloxane domains, is less than 40%, while the volume fraction of polysiloxane domains having a diameter of more than 200 nm is less than 1% and while the volume fraction of polysiloxane domains having a diameter of more than 500 nm is less than 0.1%.

[0064] The advantageous relative solution viscosity of the polysiloxane-polycarbonate block copolymers produced by the process according to the invention, having a polysiloxane content of 4.5% to 5.5%, means that the above-mentioned advantages of such polysiloxane-polycarbonate block copolymers are achieved to a large extent, in particular because such polysiloxane-polycarbonate block copolymers are particularly easily processable, for example by injection molding or extrusion.

[0065] The very particularly preferred range is selected so that the polysiloxane-polycarbonate block copolymer with this polysiloxane content can achieve good mechanical properties and good processability at the same time as the specified relative solution viscosity. The increased relative solution viscosity, especially at higher polysiloxane contents, may lead to non-optimal processability. However, it is possible to establish a polysiloxane content that corresponds to the very particularly preferred range by mixing in a conventional polycarbonate with a lower relative solution viscosity. Such a mixture is again characterized by good flowability and at the same time good mechanical properties. Those skilled in the art are also familiar with the mixing / formulation of conventional polycarbonates with polysiloxane-polycarbonate block copolymers, and in particular with the relative solution viscosity that the conventional polycarbonate must have in order to achieve the desired relative solution viscosity of the mixture of conventional polycarbonates with polysiloxane-polycarbonate block copolymers. Therefore, especially when the polysiloxane content in the polysiloxane-polycarbonate block copolymer is high, the combination of polysiloxane content and relative solution viscosity can be achieved by the prior art blending of polysiloxane-polycarbonate block copolymer with conventional polycarbonate, so there is no particular preferred range limit.However, when the relative solution viscosity value of the polysiloxane-polycarbonate block copolymer with high polysiloxane content is excessive, this high relative solution viscosity value may not be reduced to a value that still ensures good processability of the polysiloxane-polycarbonate block copolymer by blending with conventional polycarbonate with lower relative solution viscosity.

[0066] The polysiloxane-polycarbonate block copolymers produced by the process according to the invention exhibit robust fracture behavior down to -60°C in notched impact tests according to ISO 7391 / ISO 180A, even at low polysiloxane contents.

[0067] This is surprising because the high shear rates used in step (3.a) impose high mechanical stresses, especially thermal stresses, on the reaction mixture containing the oligocarbonate and the hydroxyaryl-terminated polysiloxane, and especially on the polysiloxane-polycarbonate block copolymer formed therefrom, which leads to undesirable side reactions that may result in undesirable discoloration, especially yellowing, of the polysiloxane-polycarbonate block copolymer, and in lower mechanical properties, especially lower low temperature impact strength, of the molded articles made from the polysiloxane-polycarbonate block copolymers produced by the process according to the invention.

[0068] One skilled in the art would avoid producing polysiloxane-polycarbonate block copolymers using such high shear rates.

[0069] However, it has now been found that by applying a selected low pressure, a selected temperature and a selected surface renewal frequency in a process for producing polysiloxane-polycarbonate block copolymers, while at the same time using a selected high shear rate, process conditions with lower thermal stresses can be achieved.

[0070] This was surprising to those skilled in the art, and it was especially surprising to those skilled in the art that this was also achieved in the second embodiment, i.e. the use of at least two thin-film evaporators arranged in series, even though no compatibilizer was used.

[0071] According to the invention, in process step (3), the following process conditions are applied in a single thin-film evaporator or in the last thin-film evaporator of a series of thin-film evaporators: (3.aa) the shear rate between the rotating outer edge of the wiper blade element and the axially extending rotationally symmetric inner surface area of ​​the reaction chamber of the thin film evaporator is 500 1 / s to 4000 1 / s; It is preferable that the following is observed:

[0072] This preferred embodiment of the method according to the invention is the third embodiment according to the first embodiment described above or the second embodiment described above.

[0073] According to the invention, in process step (3), the following process conditions are applied in a single thin-film evaporator or in the last thin-film evaporator of a series of thin-film evaporators: (3.ba) the pressure in the reaction chamber of the thin film evaporator is 0.1 mbara to 6 mbara, preferably 0.2 mbara to 2 mbara; It is also preferable when

[0074] This more preferred embodiment of the method according to the invention is the fourth embodiment according to the first embodiment described above or the second embodiment described above.

[0075] According to the present invention, it is also preferred that the oligocarbonate provided in step (1) has a relative solution viscosity of 1.11 to 1.22, particularly preferably 1.13 to 1.20.

[0076] This very particularly preferred embodiment of the method according to the invention is the fifth embodiment according to the first embodiment described above or the second embodiment described above.

[0077] Likewise, according to the present invention, it is preferred that the polysiloxane-polycarbonate block copolymer produced according to the first embodiment of the method according to the present invention and the polysiloxane-polycarbonate block copolymer produced according to the second embodiment of the method according to the present invention both have a polysiloxane content of 2% to 15% by weight, said polysiloxane content being based on the total weight of the polysiloxane-polycarbonate block copolymer.

[0078] This more preferred embodiment of the method according to the invention is the sixth embodiment according to the first embodiment described above or the second embodiment described above.

[0079] According to the present invention, it is particularly preferred that the polysiloxane-polycarbonate block copolymer has a polysiloxane content of 3% to 10% by weight, said polysiloxane content being based on the total weight of the polysiloxane-polycarbonate block copolymer.

[0080] This particularly preferred embodiment of the method according to the invention is the seventh embodiment according to the sixth embodiment described above.

[0081] According to the present invention, it is highly preferred that the polysiloxane content of the polysiloxane-polycarbonate block copolymer is between 4% and 8% by weight, said polysiloxane content being based on the total weight of the polysiloxane-polycarbonate block copolymer.

[0082] This very particularly preferred embodiment of the method according to the invention is the eighth embodiment according to the seventh embodiment described above.

[0083] According to the invention it is very particularly preferred that the polysiloxane content of the polysiloxane-polycarbonate block copolymer is between 4.5% and 5.5% by weight, said polysiloxane content being based on the total weight of the polysiloxane-polycarbonate block copolymer.

[0084] This very particularly preferred embodiment of the method according to the invention is the ninth embodiment according to the eighth embodiment described above.

[0085] According to the present invention, it is further preferred that the OH group content of the oligocarbonate provided in step (1) is from 1200 ppm to 2300 ppm, particularly preferably from 1400 ppm to 2200 ppm.

[0086] This more preferred embodiment of the method according to the invention is the tenth embodiment according to the first embodiment described above or the second embodiment described above.

[0087] According to the present invention, in step (1), it is more preferable to produce a reaction mixture containing an oligocarbonate having a relative solution viscosity of 1.08 to 1.22, preferably 1.11 to 1.22, and particularly preferably 1.13 to 1.20, and having an OH group content of 1000 ppm to 2500 ppm, preferably 1200 ppm to 2300 ppm, and particularly preferably 1400 ppm to 2200 ppm, and containing a hydroxyaryl-terminated polysiloxane, using a dynamic mixer and / or a static mixer.

[0088] This further preferred embodiment of the method according to the invention is the eleventh embodiment according to the first embodiment described above or the second embodiment described above.

[0089] When the number of thin-film evaporators arranged in series is at least two, in step (3) of the process, the following process conditions are satisfied: In the first thin film evaporator, (3.1.a) a shear rate between the outer edge of the rotating wiper blade element and the axially extending rotationally symmetric inner surface area of ​​the reaction chamber of the thin film evaporator of 500 1 / s to 5000 1 / s; (3.1.b) Pressure in the reaction chamber between 1 mbara and 10 mbara; (3.1.c) the temperature of the reaction mixture in the reaction chamber between 270°C and 350°C; (3.1.d) a surface renewal frequency of the reaction mixture between 10 Hz and 30 Hz; In the final thin film evaporator, (3.2.a) a shear rate between the outer edge of at least two rotating wiper blade elements and the axially extending rotationally symmetric inner surface area of ​​the reaction chamber of the thin film evaporator of 500 1 / s to 4000 1 / s, preferably 500 1 / s to 2000 1 / s; (3.2.b) a pressure in the reaction chamber of 0.1 mbara to 3 mbara, preferably 0.2 mbara to 2 mbara; (3.2.c) the temperature of the reaction mixture in the reaction chamber between 280°C and 370°C; (3.2.d) Surface renewal frequency of the reaction mixture between 10 Hz and 30 Hz; is preferably observed.

[0090] This embodiment of the method according to the invention is a twelfth embodiment according to the second embodiment described above.

[0091] According to the present invention, the term "intermediate polysiloxane-polycarbonate block copolymer", for example as obtained in step (3), is used to distinguish it from the polysiloxane-polycarbonate block copolymer, for example as obtained in step (6). Therefore, the term "intermediate" is used to clarify that the intermediate polysiloxane-polycarbonate block copolymer has a lower molecular weight than the polysiloxane-polycarbonate block copolymer. Therefore, the intermediate polysiloxane-polycarbonate block copolymer has a lower relative solution viscosity than the polysiloxane-polycarbonate block copolymer. Therefore, the intermediate polysiloxane-polycarbonate block copolymer has a relative solution viscosity of 1.20 to 1.27. The adjective "intermediate" in the term "intermediate polysiloxane-polycarbonate block copolymer" refers to the formed repeat units of hydroxyaryl-terminated polysiloxane (already a polymer) and oligocarbonate (already an oligomer), and it is understood that the intermediate polysiloxane-polycarbonate block copolymer can also be specifically a "polymer". However, in contrast to the final product, the intermediate polysiloxane-polycarbonate block copolymer has fewer formed repeat units. It is clear to those skilled in the art that the use of an oligocarbonate with a lower relative solution viscosity generally results in an intermediate polysiloxane-polycarbonate block copolymer with a similarly lower relative solution viscosity. It is also clear to those skilled in the art that the intermediate polysiloxane-polycarbonate block copolymer also contains more condensed oligocarbonates with a higher relative solution viscosity than the oligocarbonate used in step (1).

[0092] The reaction mixture for producing the polysiloxane-polycarbonate block copolymers traverses continuously two thin-film evaporators arranged in series, which are directly connected to each other via a pipe conduit. It is preferred that there is no further reactor between these two thin-film evaporators. However, pumps or mixing elements, such as static mixers or dynamic mixers, can be used in the connection between the thin-film evaporators. These pumps or these mixing elements are not considered as reactors, since the purpose of these pumps or these mixing elements is simply the mechanical processing of the substances. The second thin-film evaporator may be followed by a further thin-film evaporator or two or more further thin-film evaporators, all arranged in series.

[0093] When only one thin-film evaporator is used, the application rate of the reaction mixture per unit internal surface area of ​​the reaction chamber is 20 kg / m 2 h~100kg / m 2 h of reaction mixture. When two or more thin-film evaporators are used, the application rate of the reaction mixture per unit of the total internal surface area of ​​the reaction chambers of the thin-film evaporators arranged in series is 20 kg / m 2 h~100kg / m 2 h reaction mixture. This is particularly true when exactly two thin-film evaporators arranged in series are used in the process according to the invention.

[0094] The use of thin film evaporators for the polycondensation of polysiloxane-polycarbonate block copolymers is known in principle, for example from the above-mentioned US Pat. No. 5,399,633 or US Pat. No. 5,399,633. However, no detailed process using a thin film evaporator is described, only theoretical options for configuring the process via a thin film evaporator. No exemplary embodiment using a thin film evaporator is specified. This document does not provide any practical teaching on how to carry out the process, which allows the production of polysiloxane-polycarbonate block copolymers with good flowability and at the same time a fine polysiloxane domain size distribution.

[0095] Furthermore, it has now been demonstrated that the use of at least one thin-film evaporator can significantly reduce the residence time compared to the use of a high-viscosity reactor or a rotating disk reactor, and this also applies when at least two thin-film evaporators are placed in series.

[0096] This is surprising, since it is assumed that the use of at least two thin-film evaporators arranged in series extends the total residence time of the reaction mixture provided in step (1) and the polysiloxane-polycarbonate block copolymer obtained therefrom in the at least two thin-film evaporators arranged in series, compared to the use of only one thin-film evaporator. This is expected to increase the thermal stress on the polysiloxane-polycarbonate block copolymer obtained. This is expected to cause undesirable side reactions that are expected to result in undesirable discoloration, especially yellowing, of the polysiloxane-polycarbonate block copolymer, and in the lower mechanical properties, especially lower low-temperature impact strength, of the molded article produced from the polysiloxane-polycarbonate block copolymer produced by the method according to the present invention.

[0097] Therefore, one skilled in the art would have avoided producing polysiloxane-polycarbonate block copolymers using two or more thin film evaporators in series.

[0098] However, it has been found that in the process for producing polysiloxane-polycarbonate block copolymers having a polysiloxane content of 2% to 15% by weight, preferably having a polysiloxane content of 3% to 10% by weight, particularly preferably having a polysiloxane content of 4.5% to 5.5% by weight, it is also possible to establish process conditions of lower thermal stress when using at least two thin-film evaporators than when using only one thin-film evaporator.

[0099] Also, when two thin film evaporators are used, the process parameters, such as the surface renewal frequency, temperature, pressure or shear rate, can be varied in a wider range, making the manufacturing process less susceptible to failure and easier to adapt to changes in process conditions, such as the different characteristics of the oligocarbonate added in step (1) or the hydroxyaryl-terminated polysiloxane added in step (1).

[0100] The present invention further provides a polysiloxane-polycarbonate block copolymer comprising the following features: a polysiloxane content of 2% to 15% by weight based on the total weight of the polysiloxane-polycarbonate block copolymer; The polysiloxane domains have a fine size distribution, i.e. In the polysiloxane-polycarbonate block copolymer, the volume fraction of polysiloxane domains having a diameter of more than 100 nm, measured based on the total volume of the polysiloxane domains, is less than 70%, while the volume fraction of polysiloxane domains having a diameter of more than 200 nm is less than 30%, while the volume fraction of polysiloxane domains having a diameter of more than 500 nm is less than 0.1%, and while the relative solution viscosity is 1.38 to 1.24, preferably 1.36 to 1.26, particularly preferably 1.35 to 1.27, which is also referred to herein as the desired relative solution viscosity. Preferably, in the polysiloxane-polycarbonate block copolymer, the volume fraction of polysiloxane domains having a diameter of more than 100 nm, measured based on the total volume of the polysiloxane domains, is less than 60%, and at the same time the volume fraction of polysiloxane domains having a diameter of more than 200 nm is less than 20%, and at the same time the volume fraction of polysiloxane domains having a diameter of more than 500 nm is less than 0.1%, again with a relative solution viscosity of 1.38 to 1.24, preferably 1.36 to 1.26, particularly preferably 1.35 to 1.27, again this relative solution viscosity being referred to as the desired relative solution viscosity. Particularly preferably, in the polysiloxane-polycarbonate block copolymer, the volume fraction of polysiloxane domains having a diameter of more than 100 nm, measured based on the total volume of the polysiloxane domains, is less than 50%, and at the same time the volume fraction of polysiloxane domains having a diameter of more than 200 nm is less than 10%, and at the same time the volume fraction of polysiloxane domains having a diameter of more than 500 nm is less than 0.1%, again with a relative solution viscosity of 1.38 to 1.24, preferably 1.36 to 1.26, particularly preferably 1.35 to 1.27, which is also referred to as the desired relative solution viscosity. Very particularly preferably, in the polysiloxane-polycarbonate block copolymer, the volume fraction of polysiloxane domains having a diameter of more than 100 nm, measured based on the total volume of the polysiloxane domains, is less than 40%, and at the same time the volume fraction of polysiloxane domains having a diameter of more than 200 nm is less than 1% and at the same time the volume fraction of polysiloxane domains having a diameter of more than 500 nm is less than 0.1%, again with a relative solution viscosity of 1.38 to 1.24, preferably 1.36 to 1.26, particularly preferably 1.35 to 1.27, again this relative solution viscosity being referred to as the desired relative solution viscosity.

[0101] Preferably, the polysiloxane-polycarbonate block copolymers according to the invention have a polysiloxane content of 3% to 10% by weight, particularly preferably a polysiloxane content of 4% to 8% by weight.

[0102] Insofar as the polysiloxane-polycarbonate block copolymers prepared by the process according to the invention very particularly preferably have a polysiloxane content of 4.5% to 5.5% by weight, they also have a relative solution viscosity of 1.24 to 1.34, preferably 1.26 to 1.33 and particularly preferably 1.27 to 1.32, where again the following applies:

[0103] The polysiloxane domains have a fine size distribution, i.e. In the polysiloxane-polycarbonate block copolymer, the volume fraction of polysiloxane domains greater than 100 nm in diameter is less than 70%, while the volume fraction of polysiloxane domains greater than 200 nm in diameter is less than 30%, and while the volume fraction of polysiloxane domains greater than 500 nm in diameter is less than 0.1%, measured based on the total volume of the polysiloxane domains.

[0104] Preferably, in the polysiloxane-polycarbonate block copolymer, the volume fraction of polysiloxane domains having a diameter of more than 100 nm is less than 60%, while the volume fraction of polysiloxane domains having a diameter of more than 200 nm is less than 20%, and while the volume fraction of polysiloxane domains having a diameter of more than 500 nm is less than 0.1%, measured based on the total volume of the polysiloxane domains.

[0105] Particularly preferably, in the polysiloxane-polycarbonate block copolymer, the volume fraction of polysiloxane domains having a diameter of more than 100 nm is less than 50%, while the volume fraction of polysiloxane domains having a diameter of more than 200 nm is less than 10%, and while the volume fraction of polysiloxane domains having a diameter of more than 500 nm is less than 0.1%, measured based on the total volume of the polysiloxane domains.

[0106] Very particularly preferably, in the polysiloxane-polycarbonate block copolymer, the volume fraction of polysiloxane domains having a diameter of more than 100 nm, measured based on the total volume of the polysiloxane domains, is less than 40%, while the volume fraction of polysiloxane domains having a diameter of more than 200 nm is less than 1% and while the volume fraction of polysiloxane domains having a diameter of more than 500 nm is less than 0.1%.

[0107] The advantageous relative solution viscosity of the polysiloxane-polycarbonate block copolymers produced by the process according to the invention, which have a polysiloxane content of 4.5% to 5.5%, means that the above-mentioned advantages of such polysiloxane-polycarbonate block copolymers are largely achieved, in particular because such polysiloxane-polycarbonate block copolymers are particularly easily processable, for example by injection molding or extrusion.

[0108] The polysiloxane-polycarbonate block copolymers produced by the process according to the invention exhibit robust fracture behavior down to -60°C in notched impact tests according to ISO 7391 / ISO 180A, even at low polysiloxane contents.

[0109] The invention further provides the use of the polysiloxane-polycarbonate block copolymers according to the invention for producing molded bodies, in particular by injection molding or extrusion.

[0110] The invention further provides the use of the polysiloxane-polycarbonate block copolymers according to the invention for the manufacture of housings, helmets, dishwasher safe household items, kettle sight glasses, adjustment knobs and buttons, snap closures, cake and chocolate moulds, plug connectors for photovoltaic power plants, couplings for photovoltaic power plants.

[0111] As regards their use for the manufacture of housings, the polysiloxane-polycarbonate block copolymers according to the invention are suitable for the manufacture of housings for the following articles: Medical equipment, mobile electrical small appliances, mobile scanners, mobile play stations, mobile music players, wearable devices, sensors or computing equipment for the Internet of Things, mobile electrical charging equipment, mobile electrical adapters, control means for mechanical engineering, smart meters, mobile wireless devices, tablet computers, charging stations for electrical equipment, antenna housings for 5G base stations, outdoor electrical applications, switchboards, automated teller machines, parking meters.

[0112] In both the first embodiment of the process according to the invention and the second embodiment of the process according to the invention, the preparation of the oligocarbonates used in step (1) of the process according to the invention is carried out via a melt transesterification process, as disclosed, for example, in WO 2019238419, the disclosure content of which regarding the preparation is incorporated herein by reference. The preparation of oligocarbonates useful for step (1) of the process according to the invention is also described in DE 10119851 A1, WO 02077066 A1, WO 02077067 A1 or WO 02085967 A1.

[0113] The discharge of the fully reacted molten polysiloxane-polycarbonate block copolymer from the last evaporator of the series of thin-film evaporators, preferably also from the only one in the case of using only one thin-film evaporator, or from the second of the two thin-film evaporators in the case of using exactly two thin-film evaporators in series, can be carried out using a single screw, a twin screw or a gear pump. The discharge of the molten polysiloxane-polycarbonate block copolymer from the last evaporator of the series of thin-film evaporators can be optionally followed by the feeding and incorporation of additives and / or additives. The incorporation of additives can be carried out in the discharger or in a static mixer downstream of the discharger. The melt of the polysiloxane-polycarbonate block copolymer is then shaped using one or more nozzles and pulverized by a pelletizer according to the prior art.

[0114] The finer polysiloxane domain size distribution in the polysiloxane-polycarbonate block copolymers produced by the method according to the invention leads to an improvement in the aesthetic appearance of the polysiloxane-polycarbonate block copolymers, for example a more uniform surface structure, and a reduction in the formation of flow lines or striping or undesirable optical interference in injection molded bodies made from the polysiloxane-polycarbonate block copolymers according to the invention. The tendency of demixing of the polysiloxane phase from the polycarbonate phase is reduced, widening the processing window for injection molding of the polysiloxane-polycarbonate block copolymers produced according to the invention. The tendency of delamination in bodies produced from the polysiloxane-polycarbonate block copolymers produced according to the invention is also reduced.

[0115] This is particularly true when the polysiloxane-polycarbonate block copolymers produced by the method according to the invention have a polysiloxane content of 4.5% to 5.5% by weight.

[0116] Molded articles produced from the polysiloxane-polycarbonate block copolymers produced according to the invention exhibit robust fracture behavior down to -60°C in notched impact tests according to ISO 7391 / ISO 180A, even with low polysiloxane contents.

[0117] The oligocarbonate used according to the invention and the hydroxyaryl-terminated polysiloxane used according to the invention can be reacted in step (3) using a catalyst. An uncatalyzed reaction mode is in principle possible, but as a result higher temperatures or longer residence times may have to be tolerated.

[0118] Suitable catalysts for the process according to the invention are, for example: Ammonium catalysts such as tetramethylammonium hydroxide, tetramethylammonium acetate, tetramethylammonium fluoride, tetramethylammonium tetraphenylborate, dimethyldiphenylammonium hydroxide, tetraethylammonium hydroxide, cetyltrimethylammonium tetraphenylborate and cetyltrimethylammonium phenoxide. Particularly suitable catalysts include those of formula (K): [ka] (In the formula, R a , R b , R c and R d can be the same or different C1-C10 alkyl, C6-C14 aryl, C7-C15 arylalkyl or C5-C6 cycloalkyl, preferably methyl or C6-C14 aryl, particularly preferably methyl or phenyl; A - can be an anion such as hydroxide, sulfate, hydrogen sulfate, hydrogen carbonate, carbonate or a halide, preferably chloride, or an alkoxide or aroxide of formula -OR, where R can be C6-C14 aryl, C7-C15 arylalkyl or C5-C6 cycloalkyl, preferably phenyl).

[0119] Particularly preferred catalysts are tetraphenylphosphonium chloride, tetraphenylphosphonium hydroxide or tetraphenylphosphonium phenoxide, with tetraphenylphosphonium phenoxide being very particularly preferred. It is particularly preferred to use the alkali metal or alkaline earth metal salts of these ammonium and / or phosphonium catalysts.

[0120] The catalyst is preferably used in an amount of 0.0001% to 1.0% by weight, preferably 0.001% to 0.5% by weight, particularly preferably 0.005% to 0.3% by weight and very particularly preferably 0.01% to 0.15% by weight, based on the weight of the oligocarbonate used.

[0121] The catalysts can be used alone or as a catalyst mixture and can be added in pure form or as a solution, for example in water or phenol, for example as a solid solution with phenol. The catalysts can be introduced into the reaction, for example by means of a masterbatch or preferably together with the oligocarbonate, or can be added separately / additionally.

[0122] Oligocarbonates and hydroxyaryl-terminated polysiloxanes are mixed at pK values ​​ranging from 3 to 7. A It is also preferred to react in the presence of an organic or inorganic salt of a weak acid having a molecular weight of 0.1 to 1.0 kg / mole (25° C.). This salt may also be referred to as a cocatalyst in the context of the present invention. Suitable weak acids include carboxylic acids, preferably C2 to C22 carboxylic acids, such as acetic acid, propanoic acid, oleic acid, stearic acid, lauric acid, benzoic acid, 4-methoxybenzoic acid, 3-methylbenzoic acid, 4-tert-butylbenzoic acid, p-tolueneacetic acid, 4-hydroxybenzoic acid and salicylic acid, partial esters of polycarboxylic acids, such as monoesters of succinic acid, partial esters of phosphoric acid, such as mono- or di-organophosphates, branched aliphatic carboxylic acids, such as 2,2-dimethylpropionic acid, 2,2-dimethylbutanoic acid, 2,2-dimethylpentanoic acid and 2-ethylhexanoic acid.

[0123] Suitable organic or inorganic salts are selected or derived from hydrogen carbonate, potassium hydrogen carbonate, lithium hydrogen carbonate, sodium carbonate, potassium carbonate, lithium carbonate, sodium acetate, potassium acetate, lithium acetate, sodium stearate, potassium stearate, lithium stearate, sodium oleate, potassium oleate, lithium oleate, sodium benzoate, potassium benzoate, lithium benzoate, disodium, dipotassium or dilithium salts of bisphenol A. The salts may further comprise calcium hydrogen carbonate, barium hydrogen carbonate, magnesium hydrogen carbonate, strontium hydrogen carbonate, calcium carbonate, barium carbonate, magnesium carbonate, strontium carbonate, calcium acetate, barium acetate, magnesium acetate, strontium acetate, calcium stearate, barium stearate, magnesium stearate, strontium stearate and the corresponding oleates. These salts can be used alone or in any desired mixture.

[0124] The salts are particularly preferably selected from the group consisting of the alkali metal, alkaline earth metal and phosphonium salts of carboxylic acids. In a further preferred embodiment, the organic or inorganic salts are derived from carboxylic acids.

[0125] The organic or inorganic salts are preferably used in an amount of from 0.08 ppm to 10 ppm, very particularly preferably from 0.1 ppm to 5 ppm, based on the total weight of polysiloxane and organic or inorganic salt.

[0126] In a preferred embodiment, the organic or inorganic salt is a sodium salt, preferably a sodium salt of a carboxylic acid. The organic or inorganic salt is preferably used in an amount such that the sodium content in the resulting polysiloxane-polycarbonate block copolymer ranges from 0.003 ppm to 0.5 ppm based on the total weight of the polysiloxane-polycarbonate block copolymer formed. The cocatalyst is preferably dissolved in the hydroxyaryl-terminated polysiloxane in a suitable solvent. The sodium content of the polysiloxane-polycarbonate block copolymer can be determined, for example, by atomic emission spectroscopy.

[0127] It is advantageous to have a lower sodium content in the resulting polysiloxane-polycarbonate block copolymer than the prior art, since higher sodium contents can increase decomposition of the polysiloxane-polycarbonate block copolymer under thermal stress.

[0128] The organic or inorganic salt can be used alone or in any desired mixture. The organic or inorganic salt can be added as a solid or in a solution. In a preferred embodiment, the organic or inorganic salt is added in the form of a mixture containing the hydroxyaryl-terminated polysiloxane and the organic or inorganic salt.

[0129] The catalysts may be used alone or in admixture and may be added in pure form or as a solution, for example in water or phenol.

[0130] It is particularly preferred when at least one catalyst is incorporated into the oligocarbonate and a co-catalyst is incorporated into the hydroxyaryl-terminated polysiloxane.

[0131] Oligocarbonate (Component A) The oligocarbonate in the context of the present invention (hereinafter also referred to as component (A)) is preferably a homooligocarbonate. The oligocarbonate may be linear or branched in a known manner. The preparation of the oligocarbonate used according to the present invention is carried out as described above, preferably by a melt transesterification process, in particular according to WO 2019238419. The preparation of the oligocarbonates useful in the process according to the invention is also described in DE 10119851, WO 02077066, WO 02077067 or WO 02085967.

[0132] To prepare the polysiloxane-polycarbonate block copolymers according to the invention, it is preferable to use oligocarbonates having a molecular weight (Mw) of 5000 g / mol to 20000 g / mol, particularly preferably 8000 g / mol to 19000 g / mol, particularly preferably 10000 g / mol to 18000 g / mol. The oligocarbonates preferably have a phenolic OH group content of 1000 ppm to 2500 ppm, preferably 1300 ppm to 2300 ppm, particularly preferably 1400 ppm to 2200 ppm. The phenolic OH groups are preferably determined by IR spectroscopy. In the context of the present invention, ppb and ppm are understood to mean parts by weight, unless otherwise stated.

[0133] The method used to determine the molar masses reported in the context of this invention for oligocarbonates, hydroxyaryl-terminated polysiloxanes or polysiloxane-polycarbonate block copolymers is Method No. 2301-0257502-09D of Currenta GmbH & Co. OHG, available at any time upon request from Currenta GmbH & Co. OHG.

[0134] It is further preferred when oligocarbonates having a relative solution viscosity of 1.08 to 1.22 are used for the preparation of the polysiloxane-polycarbonate block copolymers according to the invention. The solution viscosity (ηrel; also called eta rel) is preferably determined in dichloromethane at a concentration of 5 g / l at 25° C. using an Ubbelohde viscometer.

[0135] Preferred diphenols for the preparation of oligocarbonates are 4,4'-dihydroxydiphenyl, 2,2-bis(4-hydroxyphenyl)-1-phenylpropane, 1,1-bis(4-hydroxyphenyl)phenylethane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, 2,4-bis(4-hydroxyphenyl)-2-methylbutane, 1,3-bis[2-(4-hydroxyphenyl)-2-propyl]benzene (bisphenol M), 2,2-bis(3-methyl-4-hydroxyphenyl)propane, 2,4-bis(4-hydroxyphenyl)-2-methylbutane, 1,3-bis[2-(4-hydroxyphenyl)-2-propyl]benzene (bisphenol M), 2,2-bis(3-methyl-4-hydroxyphenyl)propane, 2,4-bis(4-hydroxyphenyl)-2-methylbutane, 2,4-bis(4-hydroxyphenyl)-2-propyl]benzene ... bis(3,5-dimethyl-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, 1,3-bis[2-(3,5-dimethyl-4-hydroxyphenyl)-2-propyl]benzene, 1,1-bis(4-hydroxyphenyl)cyclohexane, and 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane.

[0136] Particularly preferred diphenols are 2,2-bis(4-hydroxyphenyl)propane (BPA), hydroquinone, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane and 2,2-bis(3-methyl-4-hydroxyphenyl)propane.

[0137] The oligocarbonates are homooligocarbonates based on bisphenol A. These homooligocarbonates very particularly preferably have phenol as end groups.

[0138] Oligocarbonates having phenol as a terminal group (phenyl-terminated oligocarbonates) are also preferred. Tert-butylphenol and cumylphenol are further possible terminal groups.

[0139] The polysiloxane-polycarbonate block copolymers obtainable by the process according to the invention preferably comprise at least one, particularly preferably two or more, of the following structures (4) to (7): [ka] TIFF2024527929000004.tif165170 wherein the phenyl rings may be mono- or di-substituted, independently of one another, with C1-C8 alkyl, halogen, preferably C1-C4 alkyl, particularly preferably methyl, X represents a single bond, C1-C6 alkylene, C2-C5 alkylidene or C5-C6 cycloalkylidene, preferably a single bond or C1-C4 alkylene, particularly preferably isopropylidene, and the total amount of structural units (4)-(7) (preferably determined by total hydrolysis using quantitative HPLC) is generally in the range of 50 ppm to 1000 ppm, preferably in the range of 80 ppm to 850 ppm. For this reason, the polysiloxane-polycarbonate block copolymer produced according to the present invention preferably contains at least one of the above-mentioned structures (4)-(7), particularly preferably two or more.

[0140] To determine the amount of rearrangement structures, each polysiloxane-polycarbonate block copolymer is subjected to total hydrolysis to form the corresponding decomposition products of formula (4a) to formula (7a), the amounts of which are determined by HPLC. This can be achieved, for example, as follows: A polysiloxane-polycarbonate block copolymer sample is hydrolyzed with sodium methoxide under reflux. The corresponding solution is acidified and concentrated to dryness. The dry residue is dissolved in acetonitrile and the phenolic compounds of formula (4a) to formula (7a) are determined using HPLC with UV detection, where the compound of formula (4a) is a decomposition product of the compound of formula (4), the compound of formula (5a) is a decomposition product of the compound of formula (5), the compound of formula (6a) is a decomposition product of the compound of formula (6), and the compound of formula (7a) is a decomposition product of the compound of formula (7): [ka] TIFF2024527929000006.tif103170

[0141] The amount of the compound of formula (4a) thus liberated is preferably 10 ppm to 500 ppm, particularly preferably 30 ppm to 300 ppm.

[0142] The amount of the compound of formula (5a) thus liberated is preferably 0 ppm (ie, below the detection limit of 10 ppm) to 100 ppm, particularly preferably 1 ppm to 50 ppm.

[0143] The amount of the compound of formula (6a) thus liberated is preferably from 1 ppm (ie, below the detection limit of 10 ppm) to 100 ppm, more preferably from 1 ppm to 50 ppm.

[0144] The amount of the compound of formula (7a) thus liberated is preferably from 10 ppm (ie, detection limit of 10 ppm) to 300 ppm, preferably from 20 ppm to 250 ppm.

[0145] Hydroxyaryl-terminated polysiloxane component (B) The polysiloxanes used according to the invention are hydroxyaryl-terminated, which is understood to mean that at least one end, preferably at least two ends and particularly preferably all ends (if three or more ends are present) of the polysiloxane bear an OH end group.

[0146] Component B is represented by formula (1): [ka] (In the formula, R 5 is hydrogen or C1-C4 alkyl, C1-C3 alkoxy, preferably hydrogen, methoxy or methyl; R 6 , R 7 , R 8 and R 9 are each independently C1 to C4 alkyl or C6 to C 12 aryl, preferably methyl or phenyl; Y is a single bond, SO2-, -S-, -CO-, -O-, C1-C6 alkylene, C2-C5 alkylidene, C6-C 12 arylene, optionally fused to a further aromatic ring containing a heteroatom, or a C5-C6 cycloalkylidene radical optionally mono- or polysubstituted by C1-C4 alkyl, preferably a single bond, -O-, isopropylidene, or a C5-C6 cycloalkylidene radical optionally mono- or polysubstituted by C1-C4 alkyl, V is oxygen, C2-C6 alkylene or C3-C6 alkylidene, preferably oxygen or C3 alkylene; p, q and r each independently represent 0 or 1; When q=0, W is a single bond, preferably simultaneously r=0, When q=1 and r=0, W is oxygen, C2-C6 alkylene or C3-C6 alkylidene, preferably oxygen or C3 alkylene; When q=1 and r=1, W and V are each independently oxygen or C2-C6 alkylene or C3-C6 alkylidene, preferably C3 alkylene; Z is C1-C6 alkylene, preferably C2 alkylene; o is the average number of repeat units from 10 to 500, preferably from 10 to 100; Preferably, the hydroxyaryl-terminated polysiloxanes are of the formula (1a), where m is the average number of repeating units from 1 to 10, preferably from 1 to 6, more preferably from 1.5 to 5. It is likewise possible to use diphenols in which two or more siloxane blocks of the general formula (1a) are linked to one another via terephthalic and / or isophthalic acid to form ester groups.

[0147] Equation (2) and Equation (3): [ka] (wherein R1 is hydrogen, C1-C4 alkyl, preferably hydrogen or methyl, particularly preferably hydrogen; each R2 is independently aryl or alkyl, preferably methyl; X is a single bond, -SO2-, -CO-, -O-, -S-, C1-C6 alkylene, C2-C5 alkylidene or C6-C 12 is arylene, optionally fused to a further aromatic ring containing a heteroatom; X is preferably a single bond, C1 to C5 alkylene, C2 to C5 alkylidene, C5 to C 12 X is preferably a single bond, isopropylidene, C5 to C6 12 cycloalkylidene or oxygen, very particularly preferably isopropylidene, n is an average number of 10 to 400, preferably 10 to 100, particularly preferably 15 to 50; (m is an average number of 1 to 10, preferably 1 to 6, and particularly preferably 1.5 to 5).

[0148] The siloxane block preferably has the following structure: [ka] In the formulae (VII), (VIII) and (IX), a represents an average number of 10 to 400, preferably 10 to 100, and particularly preferably 15 to 50.

[0149] It is also preferred if at least two identical or different siloxane blocks of general formula (VII), general formula (VIII) or general formula (IX) are linked to one another via terephthalic acid and / or isophthalic acid to form an ester group.

[0150] In formula (1a), p=0, V is a C alkylene, r=1, Z is a C alkylene, and R 8 and R 9 is methyl, q=1, W is C3 alkylene, m=1, R 5 is hydrogen or C1-C4 alkyl, preferably hydrogen or methyl, and R 6 and R 7 are each independently C1-C4 alkyl, preferably methyl, and o is 10-500.

[0151] The preparation of hydroxyaryl-terminated polysiloxanes according to any of formulas (1) to (3) is described, for example, in US Pat. No. 5,399,433, US Patent Publication No. 20130267665, or WO 2015 / 052229.

[0152] The hydroxyaryl-terminated polysiloxanes of formula (1), (2) or (3) or of formula (VII) or (VIII) are used in an amount of 0.5% to 50% by weight, preferably 1% to 40% by weight, particularly preferably 2% to 20% by weight and very particularly preferably 2.5% to 10% by weight, in each case based on the sum of the masses of the oligocarbonate and the hydroxyaryl-terminated polysiloxane.

[0153] The polysiloxane-polycarbonate block copolymers obtainable by the process according to the invention and the polymer compositions further prepared therefrom can be processed into any desired moldings in the manner known for thermoplastic polymers, in particular for polycarbonates.

[0154] In this connection, the polysiloxane-polycarbonate block copolymers obtainable by the process according to the invention and the polymer compositions further produced therefrom can be converted into articles, moldings or shaped articles (molded parts), for example by hot pressing, spinning, blow molding, thermoforming, extrusion or injection molding. The use in multilayer systems is also interesting. The application of the compositions obtainable according to the invention can be used, for example, in multicomponent injection molding or as a substrate for coextrusion layers. However, application can also be to prefabricated bodies, for example by lamination with a film or coating with a solution.

[0155] Sheets or molded bodies (multilayer systems) consisting of a base layer and optional outer layer(s) can be produced by (co)extrusion, direct skinning, direct coating, insert molding, in-mold coating or any other suitable method known to the skilled person.

[0156] The polysiloxane-polycarbonate block copolymers obtainable by the process according to the invention and the polymer compositions, in particular the polycarbonate compositions, further produced therefrom can be used in any field where known aromatic polycarbonates have been used up to now and where good flowability, high toughness at low temperatures and better chemical resistance, in addition to improved demolding properties, are additionally required, for example in the production of exterior parts and exterior control boxes, seats, twin-wall seats, electrical and electronic components for large automobiles, as well as optical storage media.For this reason, the polysiloxane-polycarbonate block copolymers can be used in the IT field for computer housings, multimedia housings and mobile phone housings, in the household field for washing machines or dishwashers, etc., and in the sports field, for example as material for helmets. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS EXAMPLES

[0157] Exemplary embodiments The present invention will be described with reference to examples, but is not intended to be limited to these examples in any way. The following determination methods are used for all corresponding parameters in the present invention, unless otherwise stated.

[0158] Relative Solution Viscosity The relative solution viscosity (η rel; also called eta rel) was determined in dichloromethane at a concentration of 5 g / l at 25° C. using an Ubbelohde viscometer.

[0159] Evaluation of polysiloxane domain size and polysiloxane domain size distribution by atomic force microscopy (AFM) The polysiloxane domain size and the size distribution of the polysiloxane domains were determined by atomic force microscopy. For this purpose, the respective samples (in the form of pellet material in the extrusion batches) were sectioned under nitrogen cooling (-196°C) using an ultramicrotome. A Bruker D3100 AFM microscope was used. The AFM images were recorded at room temperature (25°C, 30% relative humidity). The "soft intermittent contact mode" or the "tapping mode" was used for the measurements. The force of about 2.8 Nm -1A "tapping mode cantilever" (pointprobe from Nanoworld) with a spring constant of 0.01 μm and a resonant frequency of about 75 kHz was used to scan the sample. The tapping force is controlled by the ratio of the target amplitude to the free vibration amplitude (amplitude of the probe tip oscillating freely in air). The sampling rate was set to 1 Hz. To document the surface morphology, phase contrast and topography images were recorded over an area of ​​2.5 μm × 2.5 μm. Polysiloxane domains were automatically evaluated by light-dark contrast from the phase contrast images using Olympus SIS image processing software (Olympus Soft Imaging Solutions GmbH, 48149, Münster, Germany). The diameter of the polysiloxane domains was determined by the diameter of the circle-equivalent area of ​​the cross-section of the polysiloxane domains seen by cutting.

[0160] Each sample is 5 × 5 mm 2 Four scans were performed over an area of ​​100 nm and the phase contrast images were evaluated by image analysis as described above. Assuming spherical objects, the volumes of the cut polysiloxane domains were calculated and statistically evaluated. Image processing software was used to classify the individual diameters and obtain a diameter distribution. This distribution was used to determine the volume fraction of polysiloxane domains with diameters less than 100 nm, less than 200 nm, and more than 500 nm. The resolution limit was 20 nm.

[0161] Starting material: Oligocarbonate (Component A) The starting material used for the preparation of the polysiloxane-polycarbonate block copolymer was a linear bisphenol A oligocarbonate with phenyl end groups and phenolic OH end groups and a relative solution viscosity of 1.17. This oligocarbonate did not contain any additives such as UV stabilizers, mold release agents or heat stabilizers. The oligocarbonate was prepared by the melt transesterification process, for example as described in WO2019238419, and was taken directly at the outlet of the high-viscosity reactor. The oligocarbonate had a phenolic end group content of 0.16% by weight.

[0162] The oligocarbonates were dried at 120° C. in a circulating air oven for at least 2 hours before use.

[0163] Hydroxyaryl-terminated polysiloxane containing a compatibilizer (Component B1) The hydroxyaryl-terminated polysiloxanes used had a hydroxy content of 14 mg KOH / g to 20 mg KOH / g and a viscosity (23°C) of 350 mPas to 650 mPas, with n ranging from 25 to 32 and m ranging from 2.5 to 4 (R 1 =H, R 2 = methyl; X = isopropylidene), the bisphenol A terminated polydimethylsiloxane of formula (3). Sodium benzoate was mixed into the polysiloxane, and the sodium content was 0.8 ppm to 1.3 ppm. One part of the siloxane Dow Corning™ 40-001 (Dow Corning Corporation) was added as a compatibilizer to 9 parts of the hydroxyaryl terminated polysiloxane.

[0164] Hydroxyaryl-terminated polysiloxane without compatibilizer (component B2) The hydroxyaryl-terminated polysiloxanes used had a hydroxy content of 14 mg KOH / g to 20 mg KOH / g and a viscosity (23°C) of 350 mPas to 650 mPas, with n ranging from 25 to 32 and m ranging from 2.5 to 4 (R 1 =H, R 2= methyl; X = isopropylidene), the bisphenol A-terminated polydimethylsiloxane of formula (3) was mixed with sodium benzoate, and the sodium content was 0.8 ppm to 1.3 ppm.

[0165] Experimental setup for Example 7 and Example 8 (invention) FIG. 1 shows the experimental setup for the experiments on one of the embodiments of the method according to the invention, steps (1) to (4) of the method according to the invention in the embodiment in which exactly two special condensation reactors are used for the production of polysiloxane-polycarbonate block copolymers by polycondensation. The oligocarbonate (component A) was introduced in the form of pellet material into the plasticizing extruder 1 by means of a weighing balance 4 and melted. The hydroxyaryl-terminated polysiloxane (component B2) was fed in liquid form into a reservoir vessel 6 and was metered continuously into the plasticizing extruder 1 via a pump 7. The metering of the hydroxyaryl-terminated polysiloxane into the plasticizing extruder 1 was carried out in the melt of the oligocarbonate, i.e. downstream of the plasticizing zone of the extruder 1. The plasticizing extruder carried out a premixing of components A and B. The mixture was fed into an INDAG DLS / M 007 dynamic mixer 5. The mixer was operated at 500 rpm. The resulting reaction mixture was subsequently sent to a first thin-film evaporator 2. The first thin-film evaporator 2 was evacuated using a vacuum pump 9. The off-gas was passed to a condenser 8, where the condensable components, in particular phenol, were separated. After being discharged from the first thin-film evaporator 2, the resulting reaction mixture, containing the intermediate polysiloxane-polycarbonate block copolymer and the unconverted oligocarbonates and the unconverted hydroxyaryl-terminated polysiloxanes, was sent by a gear pump 3 through a melt conduit to a second thin-film evaporator 2'. After the second thin-film evaporator 2', the resulting polysiloxane-polycarbonate block copolymer was spun through a die plate (not shown) using a gear pump 3' and pelletized. The second thin-film evaporator 2' was also evacuated via a vacuum pump 9', and the condensable components of the off-gas, in particular phenol, were separated in a condenser 8'.

[0166] The two thin-film evaporators 2 and 2' each have a thickness of 0.5 m 2 Each of the heat transfer areas of the two thin film evaporators 2 and 2' was passed by a vertical rotor having wiper blade elements on its periphery.

[0167] Experimental setup using a twin screw extruder (For the preparation of intermediate polysiloxane-polycarbonate block copolymers used in Comparative Examples 1 and 2, and Inventive Examples 5 and 6) The scheme of the experimental setup using a twin-screw extruder is evident from FIG.

[0168] FIG. 2 shows a scheme for the preparation of polysiloxane-polycarbonate block copolymers. The oligocarbonate (component A) was metered into the twin-screw extruder 1 via a gravimetric feeder 2. The extruder (ZSE 27 MAXX, Leistritz Extrusionstechnik GmbH, Nuremberg) was a co-rotating twin-screw extruder with a vacuum zone for the removal of vapors. The twin-screw extruder 1 consisted of eleven housing sections a-k. The addition of the oligocarbonate (component A) was carried out in housing section a via a differential weighing balance 2, and the melting of the oligocarbonate was carried out in housings b and c. Housing sections d and e were also used to incorporate the liquid hydroxyaryl-terminated polysiloxane containing a compatibilizer (component B1). Housing sections e, g, i and j were equipped with vents for the removal of condensation products, especially phenol. Housing section e was assigned to the first vacuum stage, and housing sections g, i and j were assigned to the second vacuum stage. The pressure in the first vacuum stage was 45 mbara to 65 mbara, unless otherwise stated. The pressure in the second vacuum stage was less than 1 mbara. The hydroxyaryl-terminated polysiloxane containing the compatibilizer (component B1) was initially charged into tank 3 and introduced into twin-screw extruder 1 via metering pump 4. Negative pressure was generated via vacuum pumps 5 and 6. Steam was withdrawn from twin-screw extruder 1 and passed through two condensers 7 and 8, where the condensation products, in particular phenol, were condensed. The melt of polysiloxane-polycarbonate block copolymer was formed into strands, passed through a water bath 9 and pulverized by a pelletizer 10.

[0169] Experimental setup using high viscosity reactor (For Comparative Examples 3 and 4) The scheme of the experimental setup with the high viscosity reactor is evident from Figure 3.

[0170] FIG. 3 shows a scheme for the preparation of polysiloxane-polycarbonate block copolymers. The oligocarbonate (component A) was metered into the twin-screw extruder 1 via a gravimetric feed means 4. The twin-screw extruder 1 (ZSE 27 MAXX, Leistritz Extrusionstechnik GmbH, Nuremberg) is a co-rotating twin-screw extruder with a vacuum zone for the removal of vapors. The twin-screw extruder 1 consisted of eleven housing sections a-k. The addition of the oligocarbonate took place in housing section a, and the melting of this oligocarbonate took place in housing sections b and c. The addition of the liquid hydroxyaryl-terminated polysiloxane containing a compatibilizer (component B1) took place in housing section d. Housing sections e and f were used to incorporate the liquid hydroxyaryl-terminated polysiloxane. Housing sections g, h, i and j were equipped with vents for the removal of condensation products. Housing sections g and h were assigned to the first vacuum stage, and housing sections i and j were assigned to the second vacuum stage. The pressure in the first vacuum stage was 250 mbara to 500 mbara, unless otherwise stated. The pressure in the second vacuum stage was less than 1 mbara. The hydroxyaryl-terminated polysiloxane was initially charged into a tank 6 and introduced into the twin-screw extruder 1 via a metering pump 7. Negative pressure was generated via two vacuum pumps 8. Vapors were drawn off from the twin-screw extruder 1 and collected in two condensers 9. The melt thus degassed and partially condensed was sent from the housing section k of the twin-screw extruder 1 via a conduit to the high-viscosity reactor 2.

[0171] The high-viscosity reactor 2 was a self-cleaning device with two counter-rotating rotors arranged horizontally and axially parallel. This configuration is described in EP 0 460 466 A, see FIG. 7 therein. The high-viscosity reactor 2 used had a housing diameter of 187 mm with a length of 924 mm. The inside of the high-viscosity reactor 2, where the reaction mixture could be filled, had a volume of 44.6 liters. The high-viscosity reactor was likewise connected to a vacuum pump 8 and a condenser 9. The pressure in the high-viscosity reactor 2 was 0.1 mbara to 5 mbara. After the end of the reaction, the resulting polysiloxane-polycarbonate block copolymer was discharged via the discharge screw 3 and subsequently pelletized (via a water bath 10 and a pelletizer 11).

[0172] Comparative Example 1: Experiments using a rotating disk reactor The experimental setup according to Figure 2 was initially used for the preparation of an intermediate polysiloxane-polycarbonate block copolymer. For this purpose, 9.5 kg / h of oligocarbonate (component A) with a relative solution viscosity of 1.17 were metered into the housing a of the twin-screw extruder 1 (see Figure 2). A hydroxyaryl-terminated polysiloxane containing a compatibilizer (component B1) was introduced into the housing d of the twin-screw extruder 1 at 0.475 kg / h. The twin-screw extruder 1 was operated at a speed of 400 rpm. This resulted in a shear rate between the screw chamber of the screw element of the twin-screw extruder 1 and the housing wall of the twin-screw extruder 1 of 5970 1 / s.

[0173] The extruder housings were heated according to the following scheme: housing a was unheated, housing b was at 170°C, housing c and d were at 240°C, housing e was at 250°C, housing f was at 260°C, housing g and h were at 270°C, housing i was at 275°C, housing j was at 285°C, and housing k was at 295°C. A pressure of 40 mbara was applied to housing e. A pressure of 0.6 mbara was applied to housings g, i, and j. The intermediate polysiloxane-polycarbonate block copolymer was extruded at a melt temperature of 323°C, passed through a water bath 10, and pelletized.

[0174] 10 kg of the intermediate polysiloxane-polycarbonate block copolymer thus produced was melted in a rotating disk reactor of Uhde Inventa Fischer GmbH, with two disks, each with a diameter of 800 mm. The melt was polycondensed in the rotating disk reactor at 300° C. and 1 mbara for 87 minutes, with a rotor speed of 2.5 rpm. Phenol was continuously removed. The polysiloxane-polycarbonate block copolymer thus obtained was discharged and pelletized. The polysiloxane-polycarbonate block copolymer thus obtained had a relative solution viscosity of eta rel 1.26. The disks of the reactor were wiped by a wiper, resulting in a shear rate of 10 1 / s. The shear rate of the falling film on the disk is less than 10 1 / s.

[0175] Comparative Example 2: 10 kg of intermediate polysiloxane-polycarbonate block copolymer (FIG. 2), produced using a twin-screw extruder as in Comparative Example 1, was melted in the rotating disk reactor of Comparative Example 1. The intermediate polysiloxane-polycarbonate block copolymer was polycondensed in the rotating disk reactor at 300° C. and 1 mbar for 110 minutes at a speed of 2.5 rpm. The disks of the reactor were wiped by a wiper to obtain a shear rate of 10 1 / s. The shear rate of the falling film on the disk is less than 10 1 / s. The phenol was continuously removed. The polysiloxane-polycarbonate block copolymer obtained was discharged and pelletized. The polysiloxane-polycarbonate block copolymer thus obtained has a relative solution viscosity of eta rel 1.33.

[0176] The size distribution of polysiloxane domains in the polysiloxane-polycarbonate block copolymers of Comparative Example 1 and Comparative Example 2 was determined by AFM as described above. In the polysiloxane-polycarbonate block copolymer of Comparative Example 1, 73% by volume of the polysiloxane seen in the AFM image was found to be in the polysiloxane domains larger than 500 nm, and only 7.9% by volume of the polysiloxane was found to be in the domains smaller than 200 nm. In the polysiloxane-polycarbonate block copolymer of Comparative Example 2, 34% by volume of the polysiloxane seen in the AFM image was found to be in the polysiloxane domains larger than 500 nm, and only 20% by volume of the polysiloxane was found to be in the domains smaller than 200 nm. Experience has shown that polysiloxane domains larger than 500 nm in particular cause significant surface defects in injection molded products. Even polysiloxane domains larger than 200 nm can cause poor aesthetic appearance of injection molded products, so the products of Comparative Examples 1 and 2 do not meet the requirement of fine polysiloxane domain size distribution.

[0177] Comparative Example 3 Experiments with a high viscosity reactor Using the experimental setup according to FIG. 3, 28.6 kg / h of oligocarbonate (component A) and 1.43 kg / h of hydroxyaryl-terminated polysiloxane containing a compatibilizer (component B1) were metered into the twin-screw extruder 1. The speed of the twin-screw extruder 1 was 850 rpm. This resulted in a shear rate of 12700 1 / s between the screw chambers of the screw elements of the twin-screw extruder 1 and the housing wall of the twin-screw extruder 1. The extruder housings were heated according to the following scheme: housing a unheated, housing b at 170° C., housing c and d at 240° C., housing e at 250° C., housing f at 260° C., housing g and h at 270° C., housing i at 275° C., housing j at 285° C., housing k at 295° C. A pressure of 140 mbara was applied to housing e and a pressure of 0.8 mbara was applied to each of housings g, i and j. The outlet temperature from twin screw extruder 1 was 308°C. The extruded polymer melt was transferred to high viscosity reactor 2 via a pipe conduit. The speed of the high viscosity reactor was 30 rpm. This resulted in a shear rate of 114 1 / s between the rotor of high viscosity reactor 2 and the inner wall of the housing of high viscosity reactor 2. The housing temperature of high viscosity reactor 2 was 330°C. The pressure inside high viscosity reactor 2 was 0.5 mbara. A light-colored polysiloxane-polycarbonate block copolymer with a relative solution viscosity of 1.376 was obtained.

[0178] Comparative Example 4 Experiments with a high viscosity reactor Using the experimental setup according to FIG. 3, 23.8 kg / h of oligocarbonate (component A) and 1.19 kg / h of hydroxyaryl-terminated polysiloxane containing a compatibilizer (component B1) were metered into the twin-screw extruder 1. The speed of the extruder was 700 rpm. This resulted in a shear rate of 10450 1 / s between the screw chambers of the screw elements of the twin-screw extruder 1 and the housing wall of the twin-screw extruder 1. The extruder housings of the twin-screw extruder 1 were heated according to the following scheme: housing a unheated, housing b at 170° C., housing c and d at 240° C., housing e at 250° C., housing f at 260° C., housing g and h at 270° C., housing i at 275° C., housing j at 285° C., housing k at 295° C. Housing e and each of the housings g, i and j were at standard pressure. The melt was transferred to the high-viscosity reactor 2. The speed was 45 rpm. This resulted in a shear rate of 172 1 / s between the rotor of high-viscosity reactor 2 and the inner wall of the housing of high-viscosity reactor 2. The temperature of the housing of high-viscosity reactor 2 was 310° C. The pressure applied to the housing of high-viscosity reactor 2 was 1.6 mbara. A light-colored polysiloxane-polycarbonate block copolymer was obtained with a relative solution viscosity of 1.31.

[0179] Polysiloxane domain size distribution by AFM in Comparative Example 3 and Comparative Example 4 The size of the polysiloxane domains in the products of Comparative Example 3 and Comparative Example 4 was determined by the same method as used for Comparative Example 1 and Comparative Example 2. These products do not contain polysiloxane domains larger than 500 nm. For the product of Comparative Example 3, 89.2% by volume of the polysiloxane used is in domains smaller than 100 nm, and 100% by volume of the polysiloxane used is in domains smaller than 200 nm. Thus, the product of Comparative Example 3 has a fine polysiloxane domain size distribution, but this distribution is only achievable in combination with a very high relative solution viscosity outside the desired range. Materials with such high relative solution viscosities are processable in injection molding processes, but at the expense of additional costs and complications. Comparative Example 4 shows that it is in principle possible to adapt the manufacturing process so that the relative solution viscosity is in the desired range. However, in this case, a fine polysiloxane domain size distribution is no longer obtained. In the product of Comparative Example 4, 74.8% by volume of the polysiloxane used is present in domains larger than 100 nm, and 38.4% by volume of the polysiloxane used is present in domains larger than 200 nm.

[0180] Example 5 (Invention; using exactly one thin film evaporator according to FIG. 4) In the experimental setup according to FIG. 2, initially 21 kg / h of oligocarbonate (component A) with a relative viscosity of 1.17 were metered into the housing a of the twin-screw extruder 1, and 1.05 kg / h of hydroxyaryl-terminated polysiloxane containing a compatibilizer (component B1) were introduced into the housing d of the twin-screw extruder 1. The twin-screw extruder 1 was operated at a speed of 500 rpm. This resulted in a shear rate of 7560 1 / s between the screw chambers of the screw elements of the twin-screw extruder 1 and the housing wall of the twin-screw extruder 1. The extruder housings of the twin-screw extruder 1 were heated according to the following scheme: housing a unheated, housing b at 170° C., housings c and d at 240° C., housing e at 250° C., housings f-k at 260° C. No negative pressure was applied. The absence of negative pressure means that very little, if any, of any reaction products formed, such as phenols, is vented, so essentially a physical mixture (blend) of oligocarbonate and polysiloxane is formed that has no reactive bonds.

[0181] The oligocarbonate-polysiloxane blend thus formed is melted in a plasticizing extruder 1 and conveyed by means of a gear pump (not shown) to a thin-film evaporator 2 according to FIG. 4. The blend is introduced into the thin-film evaporator 2 at a melt temperature of about 265° C. and a throughput of 20 kg / h and condensed at a housing temperature of 334° C. The pressure in the thin-film evaporator 2 was 0.4 mbara. The shear rate between the outer edge of the wiper blade element and the inner surface area of ​​the reaction chamber of the thin-film evaporator 2 was 3930 1 / s. A light-colored pellet material with a relative solution viscosity of 1.30 was obtained.

[0182] The thin-film evaporator 2 is 0.5 m 2 The heat transfer area of ​​the thin film evaporator 2 was wiped at a speed of 500 rpm by a vertical rotor having four wiper blade elements on its periphery, resulting in a surface renewal frequency of 33.3 Hz.

[0183] Example 6 (Invention; using exactly one thin film evaporator according to FIG. 4) A blend of oligocarbonate (component A) and hydroxyaryl-terminated polysiloxane containing a compatibilizer (component B1) was first prepared exactly as described in Example 5. It was melted in a plasticizing extruder 1 and conveyed by means of a gear pump (not shown) to a thin-film evaporator 2 according to FIG. 4. The blend was introduced into the thin-film evaporator 2 at a melt temperature of about 265° C. and a throughput of 18 kg / h and condensed at a housing temperature of 334° C. The pressure in the thin-film evaporator 2 was 0.4 mbar. The shear rate between the outer edge of the wiper blade element and the inner surface area of ​​the reaction chamber of the thin-film evaporator 2 was 3530 1 / s. The thin-film evaporator 2 had a thickness of 0.5 m 2 The heat transfer area of ​​the thin film evaporator 2 was wiped at a speed of 450 rpm by a vertical rotor having four wiper blade elements on its periphery, resulting in a surface renewal frequency of 30 Hz.

[0184] A light colored pellet material was obtained having a relative solution viscosity of 1.285.

[0185] Example 7 - Present invention; using exactly two thin film evaporators according to FIG. 36.9 kg / h of oligocarbonate (component A) were plasticized in the plasticizing extruder 1 and 2 kg / h of the hydroxyaryl-terminated polysiloxane without compatibilizer (component B2) were incorporated into the melt in the plasticizing extruder 1 to produce a premix. For further homogenization, the premix of oligocarbonate and the hydroxyaryl-terminated polysiloxane without compatibilizer was passed through a DLM / S 007 dynamic mixer 5 from INDAG Maschinenbau, operating at a speed of 500 rpm. At a temperature of 284° C., the premix was subsequently passed through a 0.5 m 2 The melt was discharged and pumped to a first thin-film evaporator 2 having a heat transfer area of ​​0.5 m by means of a gear pump 3. 2 The mixture was then conveyed to a second thin film evaporator 2' having a heat transfer area of ​​1000 .mu.m.

[0186] The second thin film evaporator 2' was operated with a shear rate of 860 1 / s between the outer edge of the wiper blade element and the inner surface area of ​​the reaction chamber and a pressure of 1 mbara. The upper half of the reaction chamber of the thin film evaporator 2' was heated to 320°C and the lower half to 317°C. The melt was thus further condensed and discharged at 361°C via a gear pump 3'. The heat transfer area of ​​the thin film evaporator 2 was wiped at a speed of 330 rpm by a vertical rotor with four wiper blade elements on the periphery. This results in a surface renewal frequency of 22 Hz. The heat transfer area of ​​the thin film evaporator 2' was wiped at a speed of 220 rpm by a vertical rotor with four wiper blade elements on the periphery. This results in a surface renewal frequency of 14.7 Hz.

[0187] A light colored polysiloxane-polycarbonate block copolymer was obtained having a relative solution viscosity of 1.324.

[0188] Example 8 (Invention; using exactly two thin film evaporators according to Figure 1) 41 kg / h of oligocarbonate (component A) were plasticized in the plasticizing extruder 1 and 2.32 kg / h of a hydroxyaryl-terminated polysiloxane (component B2) without compatibilizer and having an OH number of 19.2 mg KOH / g was incorporated into the melt in the plasticizing extruder 1 to produce a premix. For further homogenization, the premix of oligocarbonate and hydroxyaryl-terminated polysiloxane without compatibilizer was passed through a DLM / S 007 dynamic mixer 5 from INDAG Maschinenbau, operating at a speed of 500 rpm. At a temperature of 275° C., the premix was subsequently mixed with a 0.5 m 2 s mixer, operating at a shear rate of 710 1 / s between the outer edge of the wiper blade element and the inner surface area of ​​the reaction chamber, a housing temperature of 290° C. and a pressure of 1 mbara. 2 The melt was discharged and pumped to a first thin-film evaporator 2 having a heat transfer area of ​​0.5 m by means of a gear pump 3. 2 The mixture was then conveyed to a second thin film evaporator 2' having a heat transfer area of ​​1000 .mu.m.

[0189] The second thin film evaporator 2' was operated with a shear rate of 635 1 / s between the outer edge of the wiper blade element and the inner surface area of ​​the reaction chamber and a pressure of 1 mbara. The upper half of the thin film evaporator 2' was uniformly heated to 310 ° C. The melt was thus further condensed and discharged at 329 ° C via a gear pump 3'. The heat transfer area of ​​the thin film evaporator 2 was wiped at a speed of 189 rpm by a vertical rotor with four wiper blade elements on the periphery. This results in a surface renewal frequency of 12.6 Hz. The heat transfer area of ​​the thin film evaporator 2' was wiped at a speed of 202 rpm by a vertical rotor with four wiper blade elements on the periphery. This results in a surface renewal frequency of 13.5 Hz.

[0190] A light colored polysiloxane-polycarbonate block copolymer was obtained having a relative solution viscosity of 1.315.

[0191] Comparative Example 1 shows that the rotating disk reactor process allows the production of polysiloxane-polycarbonate block copolymers. The relative solution viscosity of the material of Comparative Example 1, eta rel 1.26, is within the range of sufficient flowability. However, this polysiloxane-polycarbonate block copolymer contains polysiloxane domains with a diameter of more than 500 nm. The volume fraction of polysiloxane domains with a diameter of more than 500 nm is very high, at 73 volume %. Injection molded articles made from polysiloxane-polycarbonate block copolymers with this size distribution of polysiloxane domains cannot be used in many commercial applications.

[0192] Comparative Example 2 shows that longer residence time can make the polysiloxane domain distribution finer. The volume fraction of polysiloxane domains with diameters greater than 500 nm is significantly reduced. However, the relative solution viscosity also increases significantly, so the polysiloxane-polycarbonate block copolymer no longer exhibits acceptable flowability. Since the size distribution of polysiloxane domains becomes finer with increasing relative solution viscosity, it is surprising that more than one-third of the polysiloxane volume is still found in domains with diameters greater than 500 nm, even though the flowability deteriorates significantly at a relative solution viscosity of 1.33. Therefore, the injection molded article made from this polysiloxane-polycarbonate block copolymer cannot be used in many commercial applications.

[0193] For this reason, processes using rotating disk reactors do not achieve the objectives of the present invention.

[0194] Comparative Example 3 and Comparative Example 4 were carried out using a high viscosity reactor. Comparative Example 3 shows that a fine polysiloxane domain size distribution can be achieved even in a high viscosity reactor. However, the flowability is not satisfactory due to the high viscosity of the relative solution viscosity of 1.376. In contrast, Comparative Example 4 shows useful flowability but poor polysiloxane domain size distribution.

[0195] For this reason, the process using a high viscosity reactor also cannot achieve the object of the present invention.

[0196] Inventive Examples 5 and 6 show that a process using exactly one thin film evaporator, high shear rate, low pressure and high surface renewal rate at moderate temperature allows the production of polysiloxane-polycarbonate block copolymers that exhibit both fine polysiloxane domain size distribution and flow properties useful for processing in injection molding. Thus, the above-described process for producing polysiloxane-polycarbonate block copolymers using exactly one thin film evaporator achieves the objectives of the present invention.

[0197] Inventive examples 7 and 8 show that a process using a cascade of two thin film evaporators with high shear rates, low pressure and high surface renewal rates at moderate temperatures allows the production of polysiloxane-polycarbonate block copolymers that exhibit both fine polysiloxane domain size distribution and flow properties useful for processing in injection molding. Thus, the above-described process for producing polysiloxane-polycarbonate block copolymers using exactly two thin film evaporators achieves the object of the present invention. This configuration of the method according to the present invention is particularly advantageous since the object is achieved without the addition of a compatibilizer.

[0198] For convenience, the values ​​of polysiloxane domain volume fraction and associated relative solution viscosities for various associated polysiloxane domain diameters obtained in individual experiments are reproduced in Table 1.

[0199] [Table 1]

Claims

1. A method for continuously producing a polysiloxane-polycarbonate block copolymer using exactly one thin-film evaporator, the method comprising the following method steps: The method has the following method steps: (1) A method step of providing a reaction mixture containing an oligocarbonate having a relative solution viscosity of 1.08 to 1.22 and an OH group content of 1000 ppm to 2500 ppm, and containing a hydroxyaryl-terminated polysiloxane; (2) A method step of introducing the reaction mixture provided in step (1), which contains an oligocarbonate and a hydroxyaryl-terminated polysiloxane, into the exactly one thin-film evaporator; The thin-film evaporator comprises exactly one reaction chamber having exactly one rotor with at least two wiper blade elements at the periphery, the exactly one rotor rotating within the thin-film evaporator, and each wiper blade element having one outer edge; (3) A method step of reacting the reaction mixture from step (2) to obtain a polysiloxane-polycarbonate block copolymer; The reaction mixture is conveyed from the inlet of the thin-film evaporator to the outlet of the thin-film evaporator; (4) A method step of discharging the polysiloxane-polycarbonate block copolymer obtained in step (3) from the thin-film evaporator; characterized in that Here, in step (3), the following method conditions are used in the exactly one thin-film evaporator: (3.a) The shear rate between the outer edges of at least two rotating wiper blade elements at the periphery and the axially extending rotationally symmetric inner surface region of the reaction chamber of the thin-film evaporator is 500 1 / s to 5000 1 / s; (3.b) The pressure in the reaction chamber of the thin-film evaporator is 0.01 mbar a to 10 mbar a; (3.c) The temperature of the reaction mixture in the reaction chamber is 280 °C to 370 °C; (3.d) The surface renewal frequency of the reaction mixture is 10 Hz to 50 Hz; and it is observed that the method is as described above.

2. A method for continuously producing a polysiloxane-polycarbonate block copolymer using a plurality of thin-film evaporators arranged in series, the number being at least 2, The method has the following method steps: (1) A method step of providing a reaction mixture containing an oligocarbonate having a relative solution viscosity of 1.08 to 1.22 and an OH group content of 1000 ppm to 2500 ppm, and containing a hydroxyaryl-terminated polysiloxane; (2) A method step of introducing the reaction mixture provided in step (1) containing an oligocarbonate and a hydroxyaryl-terminated polysiloxane into the first evaporator of the at least two thin-film evaporators arranged in series; It should be noted that each of the at least two thin-film evaporators includes exactly one reaction chamber having exactly one rotor, each rotor has at least two wiper blade elements on its periphery, the exactly one rotor in each thin-film evaporator rotates, and each wiper blade element has one outer edge; (3) A method step of reacting the reaction mixture from step (2) to obtain a polysiloxane-polycarbonate block copolymer; It should be noted that the reaction mixture is conveyed from the inlet of the first thin-film evaporator of the at least two thin-film evaporators arranged in series to the outlet of the last thin-film evaporator of the at least two thin-film evaporators arranged in series; (4) A method step of discharging the polysiloxane-polycarbonate block copolymer obtained in step (3) from the last thin-film evaporator; characterized in that; In step (3), the following method conditions in the last evaporator of the at least two thin-film evaporators arranged in series: (3.a) The shear rate between the outer edge of the at least two rotating wiper blade elements on the periphery and the axially extending rotationally symmetric inner surface region of the reaction chamber of the thin-film evaporator is 500 1 / s to 5000 1 / s; (3.b) The pressure in the reaction chamber of the thin-film evaporator is 0.01 mbar a to 10 mbar a; (3.c) The temperature of the reaction mixture in the reaction chamber is 280 °C to 370 °C; (3.d) The surface renewal frequency of the reaction mixture is 10 Hz to 50 Hz; The method is observed to be such.

3. In method step (3), the following method conditions in the last thin-film evaporator of the single thin-film evaporator or the plurality of thin-film evaporators arranged in series: (3.a.a) The shear rate between the rotating outer edge of the wiper blade element and the axially extending rotationally symmetric inner surface region of the reaction chamber of the thin-film evaporator is 500 1 / s to 4000 1 / s; The method according to claim 1 or 2, which is observed to be such.

4. In method step (3), the following method conditions in the last thin-film evaporator of the single thin-film evaporator or the plurality of thin-film evaporators arranged in series: (3.b.a) the pressure in the reaction chamber of the thin-film evaporator is from 0.1 mbar a to 6 mbar a, The method according to claim 1 or 2, wherein the observation is made. **Claim 5** The method according to claim 1 or 2, wherein the relative solution viscosity of the oligocarbonate provided in step (1) is from 1.11 to 1.

22. **Claim 6** The method according to claim 1 or 2, wherein the polysiloxane content of the polysiloxane-polycarbonate block copolymer is from 2% by weight to 15% by weight, based on the total weight of the polysiloxane-polycarbonate block copolymer. **Claim 7** The method according to claim 6, wherein the polysiloxane content of the polysiloxane-polycarbonate block copolymer is from 4.5% by weight to 5.5% by weight, based on the total weight of the polysiloxane-polycarbonate block copolymer. **Claim 8** In step (1), the reaction mixture containing an oligocarbonate having a relative solution viscosity of 1.08 to 1.22 and an OH group content of 1000 ppm to 2500 ppm, and containing a hydroxyaryl-terminated polysiloxane, is produced using a dynamic mixer and / or a static mixer. The method according to claim 1 or 2. **Claim 9** In step (3) of the method, the following method conditions: In the first thin-film evaporator, (3.1.a) the shear rate between the outer edge of the rotating wiper blade element and the axially extending rotationally symmetric inner surface region of the reaction chamber of the thin-film evaporator is from 500 1 / s to 5000 1 / s, (3.1.b) the pressure in the reaction chamber is from 1 mbar a to 10 mbar a, (3.1.c) the temperature of the reaction mixture in the reaction chamber is from 270 °C to 350 °C, (3.1.d) the surface renewal frequency of the reaction mixture is from 10 Hz to 30 Hz, In the last thin-film evaporator, (3.2.a) the shear rate between the outer edge of the at least two rotating wiper blade elements and the axially extending rotationally symmetric inner surface region of the reaction chamber of the thin-film evaporator is from 500 1 / s to 4000 1 / s, (3.2.b) the pressure in the reaction chamber is from 0.1 mbar a to 3 mbar a, (3.2.c) the temperature of the reaction mixture in the reaction chamber is from 280 °C to 370 °C, (3.2.d) the surface renewal frequency of the reaction mixture is from 10 Hz to 30 Hz, The method according to claim 2, which is observed to be such.

10. The following features: A polysiloxane content of 2% to 15% by weight based on the total weight of the polysiloxane-polycarbonate block copolymer, In the polysiloxane-polycarbonate block copolymer, the volume fraction of polysiloxane domains having a diameter exceeding 100 nm, measured based on the total volume of the polysiloxane domains, is less than 70%, and at the same time, the volume fraction of polysiloxane domains having a diameter exceeding 200 nm is less than 30%, and at the same time, the volume fraction of polysiloxane domains having a length exceeding 500 nm is less than 0.1%, and the relative solution viscosity is 1.38 to 1.24, A polysiloxane-polycarbonate block copolymer containing the same.

11. Use of the polysiloxane-polycarbonate block copolymer according to claim 10 for the production of a molded article.

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