Production of siloxane-containing block copolycarbonates by means of compatibilizers

Abstract

The subject of the present invention is a process for the production of polysiloxane-polycarbonate block cocondensates, wherein A) at least one polycarbonate is reacted in the melt with B) at least one hydroxyaryl-terminated polysiloxane with use C) of an additive which is selected from at least one from the group consisting of a siloxane containing aromatic substituents (component C1) and a polysiloxane-polycarbonate block cocondensate A) or polysiloxane-polycarbonate block cocondensate, which can also be different from A) (component C2).

Claims

1. Process for the production of polysiloxane-polycarbonate block cocondensates, utilizing A) at least one polycarbonate, B) at least one hydroxyaryl-terminated polysiloxane, and C) at least one additive selected from the group consisting of a siloxane containing aromatic substituents (component C1) and a polysiloxane-polycarbonate block cocondensate which is obtained from the reaction of at least component A) and B) or polysiloxane-polycarbonate block cocondensate, which can also be different from the product obtained from the reaction of at least component A) and B) (component C2); said process comprising: 1) adding component C) to component A), to component B), or to a mixture of component A) and B); then 2) reacting component A) with component B) in a melt.

2. Process according to claim 1, wherein component B) is a hydroxyaryl-terminated (poly)siloxane of the formula (1), ##STR00017## wherein R.sup.5 stands for hydrogen or C1 to C4 alkyl, R.sup.6 and R.sup.7 mutually independently stand for C1 to C4 alkyl, Y stands for a single bond, —CO—, —O—, C1 to C.sub.5 alkylene, C.sub.2 to C.sub.5 alkylidene or for a C.sub.5 to C.sub.6 cycloalkylidene residue, which can be singly or multiply substituted with C.sub.1 to C.sub.4 alkyl, V stands for oxygen, C1-C6 alkylene or C2 to C5 alkylidene, W stands for a single bond, oxygen, C1 to C6 alkylene or C2 to C5 alkylidene, wherein W is not a single bond if q stands for 1, and if q is 0 then W is not oxygen, p and q mutually independently each stand for 0 or 1, o stands for an average number of repeating units from 10 to 400, and m stands for an average number of repeating units from 1 to 6.

3. Process according to claim 1, wherein component B) is a hydroxyaryl-terminated (poly)siloxane of the formulae (2) or (3): ##STR00018## wherein R1 stands for hydrogen, Cl, Br, C1-C4 alkyl, R2 independently stands for aryl or alkyl, X stands for a single bond, C1 to C5 alkylene, C2 to C5 alkylidene, C5 to C12 cycloalkylidene, —O—, —SO—, —CO—, —S—, —SO2-, n is a number between 10 and 150, and m stands for a number from 1 to 10.

4. Process according to claim 1, wherein component C) is a linear siloxane with aromatic groups with the structure (8) or a cyclic siloxane with the formula (9) Structure (8): ##STR00019## wherein R mutually independently stands for unsubstituted or singly to quadruply C1 to C4 alkyl-substituted aryl; Structure (9): ##STR00020## wherein Ra, Rb and Rc mutually independently stand for at least one residue selected from the group consisting of aryl and alkyl, and n is a whole number from 1 to 10.

5. Process according to claim 1, wherein the siloxane block is derived from the following structure: ##STR00021## wherein p stands for 1 to 5, R.sub.2 independently stands for aryl or alkyl, n stands for an average number from 10 to 150, m stands for a number from 1 to 10, a stands for an average number from 10 to 400, and R.sub.3 mutually independently comprises the following structures ##STR00022## wherein R.sub.4 mutually independently stands for hydrogen, halogen and/or in each case a C1 to C10 alkyl and e is a whole number from 2 to 12.

6. Process according to claim 1, wherein component C is a masterbatch containing 0.5 to 99.9 parts by weight of component C1 and/or C2 0.1 to 99.5 parts by weight of polycarbonate as component C3 and 0 to 1 parts by weight of a phosphonium catalyst as component C4.

7. Process according to claim 1, wherein component C) is present in the reaction melt in a quantity of 0.01 to 20 wt. %, based on the whole composition (sum of component A to C).

8. Process according to claim 1, wherein component C) is present in the reaction melt in a quantity of 0.1 to 10 wt. %, based on the whole composition (sum of component A to C).

9. Process according to claim 1, wherein component C) is present in the reaction melt in a quantity of 0.2 to 8 wt. %, based on the whole composition (sum of component A to C).

10. Process according to claim 1, wherein component C) is added to the component A) before addition of the component B).

11. Process according to claim 1, wherein component C) is melted together with the polycarbonate or in the case of a reactive extrusion is plasticized together with the polycarbonate of component A).

12. Process according to claim 1, wherein 50.0 to 0.5 wt. % of polycarbonate according to component A) is used with 0.5 to 50.0 wt. % of hydroxyaryl-terminated polysiloxane according to component B) based on the content of A) and B).

Description

Practical Examples

(1) Below, the invention is described in more detail on the basis of practical examples, wherein the determination processes described here are used for all corresponding quantities in the present invention provided that nothing to the contrary has been described.

(2) MVR

(3) The determination of the melt volume rate (MVR), unless otherwise stated, is effected according to ISO 1133 (year 2011) (at 300° C.; 1.2 kg) provided that no other conditions have been described.

(4) Solution Viscosity

(5) Determination of the solution viscosity: the relative solution viscosity (ηrel; also referred to as eta rel) was determined in dichloromethane at a concentration of 5 g/l at 25° C. with an Ubbelohde viscometer.

(6) Assessment of the Siloxane Domain Size by Atomic Force Microscopy (AFM)

(7) The siloxane domain size and distribution was determined by atomic force microscopy. For this, the relevant sample (in the form of a melt cake in laboratory systems or granules in extrusion systems) is cut up at low temperature (nitrogen cooling) by means of an ultramicrotome. A Bruker D3100 AFM microscope is used. The AFM image was recorded at room temperature (25° C., 30% relative humidity). For the measurement, the “Soft Intermittent Contact Mode” or the “Tapping Mode” was used. For scanning the sample a “Tapping Mode Cantilever” (Nanoworld point probe) with a spring constant of 2.8 Nm.sup.−1 and a resonance frequency of ca. 75 kHz was used. The tapping force is controlled via the ratio of target amplitude and free oscillation amplitude (amplitude of the probe tip on free oscillation in air). The sampling rate was set at 1 Hz. For recording the surface morphology, phase contrast and topography images were recorded on a 2.5 μm×2.5 μm area. The particles or siloxane domains were automatically assessed by Olympus SIS image assessment software (Olympus Soft Imaging Solutions GmbH, 48149, Munster, Germany) via light-dark contrast (from the phase contrast images). The diameters of the particles were determined via the diameter of the corresponding equal area circle.

(8) Several phase contrast images (number of particles greater than 200) are assessed as described above. The individual diameters are classified via the imaging software and a diameter distribution generated. The assignment to the individual D values is effected with this. The D value gives the percentage of particles which less than the stated value. With a D90 value of x, 90% of the particles are smaller than x. Further, the percentage of the particles which are smaller than 100 mm is determined from the distribution.

(9) Starting Materials

(10) Component A: Polycarbonate

(11) PC 1:

(12) As the starting material for the reactive extrusion, linear bisphenol-A polycarbonate with phenol-based groups from Covestro Deutschland AG with a melt volume index of 59-62 cm.sup.3/10 min measured at 300° C. and 1.2 kg loading (according to ISO 1033) is used. This polycarbonate contains no additives such as UV stabilizers, mould release agents or heat stabilizers. The production of the polycarbonates was effected by a melt transesterification process as described in DE 102008019503. The polycarbonate has a content of phenolic end groups of ca. 600 ppm.

(13) Component B: Siloxane

(14) Siloxane-1:

(15) Bisphenol A-terminated polydimethylsiloxane of the formula 3 with n ca. 20 and m in the range from 3 to 4 (R.sup.1=H, R.sup.2; X=isopropylidene), with a hydroxy content of 26.2 mg KOH/g and a viscosity of 366 mPa.Math.s (23° C.); the sodium content is 2.9 ppm.

(16) Siloxane-2:

(17) Hydroquinone-terminated polydimethylsiloxane with n ca. 20 and m in the range from 3 to 4 in formula (2) (R.sup.1=H, R.sup.2), with a hydroxy content of 20.8 mg KOH/g and a viscosity of 191 mPa.Math.s (23° C.); the sodium content is 4.9 ppm.

(18) Siloxane-3:

(19) Hydroquinone-terminated polydimethylsiloxane with n ca. 20 and m in the range from 3 to 4 in formula (2) (R.sup.1=H, R.sup.2), with a hydroxy content of 22.2 mg KOH/g and a viscosity of 175 mPa.Math.s (23° C.); the sodium content is ca. 3 ppm.

(20) The production of the siloxanes is for example described in U.S. Pat. No. 8,912,290.

(21) Catalyst Masterbatch (without siloxane-based added component):

(22) As the catalyst, tetraphenylphosphonium phenolate from Rhein Chemie Rheinau GmbH (Mannheim, Germany) is used in the form of a masterbatch. Tetraphenylphosphonium phenolate is used as a solid solution with phenol and contains ca. 70% tetraphenylphosphonium phenolate. The following quantities relate to the substance obtained from Rhein Chemie (as solid solution with phenol).

(23) The masterbatch is produced as a 0.25% mixture. For this, 4982 g of polycarbonate PC1 is tumbled with 18 g of tetraphenylphosphonium phenolate in the drum hoop mixer for 30 minutes. The masterbatch is introduced in the ratio 1:10, so that in the whole quantity of polycarbonate the catalyst is present in a content of 0.025 wt. %.

(24) Component C:

(25) Component C2-1:

(26) Polysiloxane-polycarbonate block cocondensate containing polysiloxane based on above-described structure according to formula (2)

(27) Production of Component C2-1:

(28) The diagram of the experimental set-up can be seen in FIG. 1.

(29) FIG. 1 shows a diagram for the production of the siloxane-containing block cocondensates. Polycarbonate (component A)) and the catalyst masterbatch (see below) are metered in via the gravimetric feeds (4) and (5) onto the double-screw extruder (1). The extruder (Type ZSE 27 MAXX from Leistritz Extrusionstechnik GmbH, Nuremberg) is a corotating double-screw extruder with vacuum zones for removal of the vapours. The extruder consists of 11 housing parts (a to k) —see FIG. 1. In housing part a, the addition of polycarbonate and catalyst masterbatch takes place and in the housing b and c the melting of these components. In housing part d, the addition of the liquid siloxane component (component B) takes place. The housing parts e and f serve for the admixture of the liquid siloxane component (component B). The housing parts g, h, i and j are provided with venting openings in order to remove the condensation products. The housing parts g and h are assigned to the first vacuum stage and the housing parts i and j to the second. The vacuum in the first vacuum stage was between 250 and 500 mbar absolute pressure. The vacuum in the second vacuum stage is less than 1 mbar. The siloxane (component B) is stocked in a tank (6) and fed into the extruder via a metering pump (7). The vacuum is generated via 2 vacuum pumps (8). The vapours are passed away from the extruder and trapped in 2 condensers (9). The melt thus degassed in passed via a pipe from the housing part k of the double-screw extruder to a high-viscosity reactor (2).

(30) The high-viscosity reactor (2) is a self-cleaning device with two contrarotating rotors arranged horizontally and with parallel axes. The design is described in European patent application EP0460466, see FIG. 7 therein. The machine used has a rotor diameter of 187 mm with a length of 924 mm. The total internal space of the reactor has a volume of 44.6 litres. The high-viscosity reactor is also connected to a vacuum pump (8) and to a condenser (9). The vacuum present on the high-viscosity reactor is 0.1 to 5 mbar. After completion of the reaction, the block cocondensate is discharged via a discharge screw and then granulated (via water bath (10) and granulator (11)).

(31) The block cocondensate was produced with the following process parameters:

(32) As the polycarbonate, the polycarbonate PC-1 was used as described above. As the siloxane, siloxane-3 was used. The feed rate of the polycarbonate component is 62 kg/h, the feed rate of the siloxane component is 3.1 kg/h. The extruder temperature is 350° C. and the temperature in the high-viscosity reactor 350° C. An opaque-white granulate with a solution viscosity of 1.306 is obtained.

(33) The process is described in more detail in WO 2015/052110.

(34) Component C1 According to Structure (9):

(35) Octaphenylcyclotetrasiloxane (CAS: 546-56-5), 95% from ABCR GmbH & Co. KG (Karlsruhe Germany).

(36) Component C2-2 Containing Structural Elements According to Structure (IX):

(37) Siloxane-containing block cocondensate with the trade name Trirex ST6-3022PJ from Samyang Corp. Korea, containing ca. 9% polydimethylsiloxane; block cocondensate containing bisphenol A-based polycarbonate and siloxanes according to structure (IX).

Example 1 (Comparative Example; Process without Component C)

(38) 42.5 g of polycarbonate granules (PC-1; 85 wt. %), 2.5 g of siloxane-1 (5 wt. %) and 5 g (10 wt. %) of catalyst masterbatch are weighed out into a 250 ml glass flask with stirrer and molecular still separator. The apparatus is evacuated and flushed with nitrogen (3× each time). The mixture is melted under vacuum within 10 minutes by a metal bath preheated to 350° C. The pressure in the apparatus is ca. 1.5 mbar. The reaction mixture is kept under this vacuum for 30 minutes with stirring. The system is then flushed with nitrogen and the polymer melt removed. An opaque-white polymer is obtained. The solution viscosity of the product is eta rel=1.439.

Example 2 (Example According to the Invention; Process with Component C)

(39) 37.5 g of polycarbonate granules (PC-1; 75 wt. %), 2.5 g of siloxane-1 (5 wt. %), 5 g (10 wt. %) of catalyst masterbatch and 5 g (10 wt. %) of component C2-1 are weighed out into a 250 ml glass flask with stirrer and molecular still separator. The apparatus is evacuated and flushed with nitrogen (3× each time). The mixture is melted within 10 minutes under vacuum by a metal bath preheated to 350° C. The pressure in the apparatus is ca. 1.5 mbar. The reaction mixture is kept under this vacuum for 30 minutes with stirring. The system is then flushed with nitrogen and the polymer melt removed. An opaque-white polymer is obtained. The solution viscosity of the product is eta rel=1.470.

(40) TABLE-US-00001 TABLE 1 Particle size distribution Particle distribution; Content of D90 value of average particles < 100 nm Example particle diameter [nm] [%] 1 (comparison) 202.9 77.3 2 (according to invention) 133.5 86.6

(41) The particle size distribution of the siloxane domains according to Table 1 shows a marked advantage when the siloxane-based added component is used. The content of particles with a diameter of less than 100 nm is higher and the D90 value markedly lower. Moreover, it can be seen that the active addition of a polysiloxane-polycarbonate block cocondensate in example 2 results in a more favourable particle distribution than the in situ formation of a polysiloxane-polycarbonate block cocondensate in example 1.

Example 3 (Comparative Example; without Component C)

(42) 42.5 g of polycarbonate granules (PC 1; 85 wt. %), and 5 g (10 wt. %) of catalyst masterbatch are weighed out into a 250 ml glass flask with stirrer and molecular still separator. The apparatus is evacuated and flushed with nitrogen (3× each time). The mixture is melted within 10 minutes at 50 mbar by a metal bath preheated to 350° C. After complete melting the system is ventilated and 2.5 g of siloxane-2 (5 wt. %) added thereto while passing nitrogen. The apparatus is now again evacuated to 50 mbar and the reaction mixture is mixed for 2 mins at greatly increased stirrer speed. The pressure in the apparatus is then lowered to ca. 1.5 mbar and the stirrer speed reduced depending on the viscosity increase of the reaction mixture. The reaction mixture is kept under this vacuum for 20 minutes with stirring. The system is then flushed with nitrogen and the polymer melt removed. An opaque-white polymer is obtained. The solution viscosity of the product is eta rel=1.335.

Example 4 (Example According to the Invention; with Component C1 and Component C2-1)

(43) 37.5 g of polycarbonate granules (PC 1; 75 wt. %), and 5 g (10 wt. %) of catalyst masterbatch and 5 g of component C2-1 (10 wt. %) and 0.105 g of component C1 (0.2 wt. %) are weighed out into a 250 ml glass flask with stirrer and molecular still separator. The apparatus is evacuated and flushed with nitrogen (3× each time). The mixture is melted within 10 minutes at 50 mbar by a metal bath preheated to 350° C. After complete melting, the system is ventilated and 2.5 g of siloxane-2 (5 wt. %) added thereto while passing nitrogen. The apparatus is now evacuated again to 50 mbar and the reaction mixture mixed for 2 mins at markedly increased stirrer speed. The pressure in the apparatus is then lowered to ca. 1.5 mbar and the stirring speed reduced depending on the viscosity increase of the reaction mixture. The reaction mixture is kept under this vacuum for 20 minutes with stirring. The system is then flushed with nitrogen and the polymer melt removed. An opaque-white polymer is obtained. The solution viscosity of the product is eta rel=1.540.

Example 5 (Example According to the Invention; Process with Component C2-2)

(44) 37.5 g of polycarbonate granules (PC-1; 75 wt. %), 5 g of component C2-2 (10 wt. %) and 5 g (10 wt. %) of catalyst masterbatch are weighed out into a 250 ml glass flask with stirrer and molecular still separator. The apparatus is evacuated and flushed with nitrogen (3× each time). The mixture is melted within 10 minutes at 50 mbar by a metal bath preheated to 350° C. After complete melting, the system is ventilated and 2.5 g of siloxane-2 (5 wt. %) added thereto while passing nitrogen. The apparatus is now again evacuated to 50 mbar and the reaction mixture mixed for 2 mins at greatly increased stirring speed. The pressure in the apparatus is then lowered to ca. 1.5 mbar and the stirring speed reduced depending on the viscosity increase of the reaction mixture. The reaction mixture is kept under this vacuum for 20 minutes with stirring. The system is then flushed with nitrogen and the polymer melt removed. An opaque-white polymer is obtained. The solution viscosity of the product is eta rel=1.432.

(45) TABLE-US-00002 TABLE 2 Particle size distribution Particle distribution; Content of D90 value of average particles < 100 nm Example particle diameter [nm] [%] 3 (comparative) 167.6 54.9 4 (according to invention) 130.6 81.8 5 (according to invention) 154.2 74.5

(46) It can be seen in Table 2 that under the chosen experimental conditions the formulations which contain the component C have a markedly higher content of small siloxane domains. Accordingly, the D90 value for these formulations is low in comparison to the comparison formulation.

Example 6 (Comparative Example; Process without Component C)

(47) The experiment is in principle performed as described in “Production of component C2-1”. In contrast thereto, the component B siloxane-3 is used, which is metered in the extruder. The process parameters were adopted unchanged. Opaque-white granules are obtained with a solution viscosity of 1.306.

Example 7 (Example According to Invention Component C1 and C2-1

(48) The experiment is in principle performed as described in “Production of the siloxane-based additional component-1”. In contrast thereto, the component B siloxane-3 is used, which is metered in the extruder. The feed rate of the polycarbonate component is 60 kg/h, the feed rate of the component B is 3.0 kg/h. The feed rate of the masterbatch containing component C (i.e. C1 and C2-1 see below) and tetraphenylphosphonium phenolate is 3 kg/h. The extruder temperature is 350° C. and the temperature in the high-viscosity reactor 350° C. Opaque-white granules with a solution viscosity of 1.312 are obtained.

(49) Composition of the masterbatch containing component C:

(50) 80% component C2-1

(51) 1.7% component C1

(52) 0.25% tetraphenylphosphonium phenolate (component C4)

(53) 18.05% PC-1 (component C3)

(54) TABLE-US-00003 TABLE 3 melt stability Ex. 6 (Comp.) Ex. 7 (according to invention) MVR 300° C./5 mins 6.9 5.6 MVR 300° C./20 mins 5.9 5.5 ΔMVR (300° C.) 1.0 0.1 MVR 320° C./5 mins 10.2 9.9 MVR 320° C./20 mins 9.4 9.5 ΔMVR (320° C.) 0.8 0.4

(55) It can be seen in Table 3 that the melt viscosity in Example 7 with the composition according to the invention is markedly higher in comparison to Comparative Example 6. This was surprising, since those skilled in the art might have expected that the melt stability decreases due to additional components.

(56) TABLE-US-00004 TABLE 4 Particle size distribution: Particle distribution; Content of D90 value of average particles < 100 nm Example particle diameters [nm] [%] 6 (Comparison) 138 72.5 7 (According to invention) 102.2 89.0

(57) It can be seen in Table 4 that in Example 7 according to the invention the content of particles with a diameter of <100 nm is markedly higher in comparison to Comparative Example 6. Also, the D90 value is significantly lower.