Method for producing moulding compounds with improved properties
阅读说明：本技术 生产具有改进的性质的模塑料的方法 (Method for producing moulding compounds with improved properties ) 是由 M·埃尔克伦茨 R·鲁道夫 H-J·蒂姆 于 2019-08-15 设计创作，主要内容包括：本发明的主题是生产具有改进的性质的模塑料的方法。本发明的主题特别是含有聚碳酸酯和增强填料的模塑料的生产。根据本发明,所述模塑料可通过使用具有相对于彼此环形布置的螺杆的多螺杆挤出机配混聚碳酸酯和增强填料获得。所述增强填料在此优选选自二氧化钛(TiO-2)、滑石(Mg-3Si-4O-(10)(OH)-2)、白云石(CaMg[CO-3]-2)、高岭石(Al-4[(OH)-8|Si-4O-(10)])和硅灰石(Ca-3[Si-3O-9])这些成员中的一个或多个成员,优选选自二氧化钛(TiO-2)和滑石(Mg-3Si-4O-(10)(OH)-2)这些成员中的一个或多个成员。根据本发明,增强填料的浓度在此为3至50重量%,在每种情况下基于模塑料的总质量计。(The subject of the invention is a process for producing molding materials having improved properties. The subject of the invention is in particular the production of moulding compositions comprising polycarbonate and reinforcing fillers. According to the invention, the moulding compound can be obtained by compounding the polycarbonate and the reinforcing filler using a multi-screw extruder having screws arranged annularly with respect to one another. The reinforcing filler is preferably selected from titanium dioxide (TiO) 2 ) Talc (Mg) 3 Si 4 O 10 (OH) 2 ) Dolomite (CaMg [ CO ] 3 ] 2 ) Kaolinite (Al) 4 [(OH) 8 |Si 4 O 10 ]) And wollastonite (Ca) 3 [Si 3 O 9 ]) One or more of these members, preferably selected from titanium dioxide (TiO) 2 ) And talc (Mg) 3 Si 4 O 10 (OH) 2 ) One or more of these members. According to the invention, the concentration of reinforcing filler is here from 3 to 50% by weight, based in each case on the total mass of the molding composition.)
1. A method for producing a molding compound containing polycarbonate and a reinforcing filler, wherein the molding compound is compounded in a ring extruder.
2. The method as claimed in claim 1, wherein the molding compound contains the following components:
97 to 50% by weight of a polycarbonate,
3 to 50% by weight of a reinforcing filler,
0 to 37% by weight of other ingredients,
wherein the total of these ingredients is 100% by weight.
3. The process as claimed in claim 1 or 2, wherein the reinforcing filler is selected from titanium dioxide (TiO)2) Talc (Mg)3Si4O10(OH)2) Dolomite (CaMg [ CO ]3]2) Kaolinite (Al)4[(OH)8|Si4O10]) And wollastonite (Ca)3[Si3O9]) One or more of these members, preferably selected from titanium dioxide (TiO)2) And talc (Mg)3Si4O10(OH)2) One or more of these members.
4. A process as claimed in any of claims 1 to 3, wherein the molding composition contains from 10% to 35% by weight, preferably from 12% to 32% by weight, particularly preferably from 15% to 30% by weight, of reinforcing filler.
5. A method as claimed in claim 4, wherein the reinforcing filler is titanium dioxide (TiO)2）。
6. A process as claimed in any of claims 1 to 3, wherein the molding composition contains from 10% to 40% by weight, preferably from 15% to 35% by weight, particularly preferably from 20% to 30% by weight, of reinforcing filler.
7. A method as claimed in claim 6, wherein the reinforcing filler is talc (Mg)3Si4O10(OH)2）。
8. A method as claimed in any of the preceding claims, wherein the moulding compound contains from 0% to 20% by weight, preferably from 0% to 10% by weight, of further constituents, where the constituents add up to 100% by weight.
9. A method as claimed in any one of the preceding claims, wherein the method comprises the steps of:
(1) adding polycarbonate, reinforcing filler and optionally other ingredients to a ring extruder;
(2) the polycarbonate and the reinforcing filler and optionally other ingredients are compounded using a ring extruder.
10. The method as set forth in any one of the preceding claims wherein the addition of the reinforcing filler is performed before the polycarbonate is melted or after the polycarbonate is melted.
11. A process as claimed in any one of the preceding claims, wherein the ring extruder has an L/D ratio of from 28 to 45, particularly preferably from 33 to 42.
12. A process as claimed in any one of the preceding claims, wherein the ring extruder has a DA/DI ratio of from 1.5 to 1.8, preferably from 1.55 to 1.74.
13. Method as claimed in any one of the preceding claims, wherein the ring extruder has a torque density of speed of harvesting from 2 to 10 Nm/cm, preferably from 4 to 8 Nm/cm, particularly preferably from 5.5 to 6.5 Nm/cm.
14. A moulding compound made by the method as claimed in any one of claims 1 to 13.
15. Use of the molding compound according to claim 14 for producing reflectors in lighting tools or structural components.
Examples
The experiments described in examples 1 to 3 were carried out using a ZE60A UTxi twin screw extruder from the company Krauss Maffei Berstorff GmbH. The twin-screw extruder used had an internal diameter of the housing of 65 mm and an L/D ratio of 43. A schematic configuration of the extruder used is shown in fig. 1. The twin-screw extruder had a housing consisting of 11 sections, in which 2 co-rotating intermeshing screws (not shown) were arranged.
In example 1, the metering of all constituents of the polycarbonate moulding compound takes place via the illustrated feed hopper 1 by means of a main feed in a housing 2. An exhaust port 13 is located in the housing portion 11 and is connected to an aspiration device (not shown).
The conveying zone for the polycarbonate granulate and the titanium dioxide powder is located in the region of the shells 2 to 5.
Plasticizing zones consisting of various double and triple threaded kneading blocks and saw tooth blocks of various widths are located in the region of the shells 6 and 7.
The mixing zone consisting of kneading elements, toothed blocks and conveying elements is located in the region of the shells 8 to 10.
The pressurized zone is located in the housing 12, followed by melt filtration (position A1 in FIG. 1) (type: DSC 176 from Maag company) and downstream thereof a nozzle plate with 29 holes.
In example 2, the polycarbonate pellets are metered in via the illustrated feed hopper 1 by means of a main feed in a housing 2. The metering of the titanium dioxide powder takes place via a side feed unit in the housing 8. An exhaust port 13 is located in the housing portion 11 and is connected to an aspiration device (not shown).
The conveying zone for the polycarbonate granulate is located in the region of the housings 2 to 5.
Plasticizing zones consisting of various double and triple threaded kneading blocks and saw tooth blocks of various widths are located in the region of the shells 6 and 7.
The mixing zone consisting of kneading elements, toothed blocks and conveying elements is located in the region of the shells 9 to 10.
The pressurized zone is located in the housing 12, followed by melt filtration (position A1 in FIG. 1) (type: DSC 176 from Maag company) and downstream thereof a nozzle plate with 29 holes.
In example 3, the metering of all constituents of the polycarbonate moulding compound takes place via the illustrated feed hopper 1 through the main feed in the housing 2. An exhaust port 13 is located in the housing portion 11 and is connected to an aspiration device (not shown).
The conveying zone for the polycarbonate granulate and the titanium dioxide powder is located in the region of the shells 2 to 7.
A plasticized zone consisting of various double and triple threaded kneading blocks of various widths and saw tooth blocks is located in the region of the housing 8.
The mixing zone consisting of saw tooth blocks is located in the area of the housing 10.
The pressurized zone is located in the housing 12, followed by melt filtration (position A1 in FIG. 1) (type: DSC 176 from Maag company) and downstream thereof a nozzle plate with 29 holes.
In examples 1 and 3, polycarbonate pellets and titanium dioxide powder were metered into hopper 1 using a commercially available gravity gravimetric weigher.
In example 2, polycarbonate pellets were metered into feed hopper 1 using a commercially available gravity gravimetric weigher. The metering of the titanium dioxide powder is carried out via a side-feed unit in the housing 8 using a commercially available gravity-type gravimetric metering scale.
In examples 1 to 3, granulation was carried out as strand granulation (strangranulierung) after cooling in a water bath.
The melt temperature measurements were carried out in examples 1 to 3 by inserting a thermocouple into the outgoing melt of the central melt strand directly in front of the nozzle.
The experiment described in example 4 (according to the invention) was carried out using a ringer xtruder RE 3 XP-type multi-screw extruder from the company extrricicom GmbH. The multi-screw extruder used had 12 screws each having a screw outer diameter of 30 mm, a DA/DI ratio of 1.55 and an L/D ratio of 39. A schematic configuration of the extruder used is shown in fig. 2. The multi-screw extruder has a housing consisting of 12 sections, in which 12 co-rotating intermeshing screws (not shown) are arranged.
The metering of all constituents of the polycarbonate moulding compound takes place in the feed hopper 14 shown by way of the main feed in the housing 15. An exhaust port 27 is located in the housing portion 25 and is connected to an aspiration device (not shown).
The conveying zone for the polycarbonate granulate and the titanium dioxide powder is located in the region of the shells 15 to 19.
A plasticized region consisting of various double-threaded kneading blocks of various widths and saw tooth mixing elements is located in the region of the housing 20.
A mixing zone consisting of various conveying and mixing elements is located in the region of the shells 22 to 24.
The pressurized zone is located in the housing 26, followed by melt filtration (position A2 in FIG. 2) (type: K-SWE-121 from Kreyenborg) and downstream thereof a nozzle plate with 24 holes.
In example 4, polycarbonate pellets and titanium dioxide powder were metered into hopper 14 using a commercially available gravity gravimetric weigher.
After cooling in a water bath, granulation was carried out in the form of strand granules.
The melt temperature measurement was performed by inserting a thermocouple into the outgoing melt of one of the two central melt beams directly in front of the nozzle.
The experiment described in example 5 was carried out using a ZE60A UTXi twin screw extruder from the company KraussMaffei Berstorff GmbH. The twin-screw extruder used had an internal diameter of the housing of 65 mm and an L/D ratio of 43. A schematic configuration of the extruder used is shown in fig. 3. The twin-screw extruder had a housing consisting of 11 sections, in which 2 co-rotating intermeshing screws (not shown) were arranged.
In example 5, the metering of all constituents of the polycarbonate moulding compound is carried out via the illustrated feed hopper 28 by means of a main feed in a housing 29. An exhaust port 40 is located in the housing portion 38 and is connected to an aspiration device (not shown).
The conveying zone for the polycarbonate granulate and the titanium dioxide powder is located in the region of the outer shells 30 to 32.
A plasticized region consisting of various double and triple threaded kneading blocks and saw tooth blocks of various widths is located in the region of the housing 33.
The mixing zone consisting of kneading elements, toothed blocks and conveying elements is located in the region of the shells 35 and 37.
The pressurised zone and the nozzle plate with 29 holes downstream thereof are located in a housing 39.
In example 5, polycarbonate pellets and titanium dioxide powder were metered into hopper 28 using a commercially available gravity gravimetric weigher.
After cooling in a water bath, granulation was carried out in the form of strand granules.
The melt temperature measurement was carried out in example 5 by inserting a thermocouple into the outgoing melt of the central melt strand directly in front of the nozzle.
The experiments described in examples 6 to 8 (according to the invention) were carried out using a multiscrew extruder of the ringer xtruder RE 1XPV type from the company Extricom GmbH. The multi-screw extruder used had 12 screws each having a screw outer diameter of 18.7 mm, a DA/DI ratio of 1.74 and an L/D ratio of 35. A schematic configuration of the extruder used is shown in fig. 4. The multi-screw extruder had a housing consisting of 7 sections, in which 12 co-rotating intermeshing screws (not shown) were arranged.
The metering of the polycarbonate pellets takes place in examples 6 to 8 via the illustrated feed hopper 41 by means of the main feed in the housing 42. The metering of the titanium dioxide powder takes place via a side feed unit in the housing 45. An exhaust port 49 is located in the housing portion 47 and is connected to an aspiration device (not shown).
The conveying zone for the polycarbonate pellets is located in the region of the housing 43.
A plasticizing zone consisting of various double flighted kneading blocks of various widths is located in the region of the housing 44.
The mixing zone consisting of kneading elements, toothed blocks and conveying elements is located in the region of the shells 45 to 47.
The pressurised zone and the nozzle plate with 7 holes downstream thereof are located in the region of the housing 48.
In examples 6 to 8 polycarbonate pellets were metered into the feed hopper 41 using a commercially available gravity gravimetric weigher. The metering of the titanium dioxide powder is carried out via a side-feed unit in the housing 45 using a commercially available gravity gravimetric metering scale.
After cooling in a water bath, granulation was carried out in the form of strand granules.
The melt temperature measurement was performed by inserting a thermocouple into the outgoing melt of the central melt beam directly in front of the nozzle.
The experiments described in examples 9 to 11 were carried out using an Evolum 32HT twin screw extruder from Clextral. The twin-screw extruder used had an internal diameter of the jacket of 32 mm and an L/D ratio of 36. A schematic configuration of the extruder used is shown in fig. 13. The twin-screw extruder had a housing consisting of 9 sections, in which 2 co-rotating intermeshing screws (not shown) were arranged.
Talc powder was metered into the housing 55 via a side feed unit (not shown) in example 9. The remaining components of the polycarbonate molding compound are supplied via feed hopper 50 as shown by the main feed in enclosure 51. An exhaust port 60 is located in the housing portion 58 which is connected to an aspiration device (not shown).
The conveying zone for the polycarbonate pellet and powder premix is located in the region of the shells 52 and 53.
A plasticized region comprised of various double and triple threaded kneading blocks and saw tooth blocks of various widths is located in the region of the housing 54.
The mixing zone consisting of kneading elements, toothed mixing elements and conveying elements is located in the region of the shells 56 to 58.
The pressurised zone and the nozzle plate with 6 holes downstream of it are located in the housing 59.
The polycarbonate pellet and powder mixture was metered into hopper 50 in example 9 via a commercially available gravity differential weighing scale and the talc powder was metered into the hopper (not shown) of the side feed unit using a commercially available gravity differential weighing scale.
After cooling in a water bath, granulation was carried out in the form of strand granules.
The melt temperature measurement was carried out in example 9 by inserting a thermocouple into the outgoing melt of one of the two central melt beams directly in front of the nozzle.
In examples 10 and 11, half of the talc powder was metered into the housing 55 via a side feed unit (not shown). The remaining ingredients of the polycarbonate molding compound, including the remaining half of the talc powder, are supplied via feed hopper 50 as shown by the main feed in housing 51. An exhaust port 60 is located in the housing portion 58 which is connected to an aspiration device (not shown).
The conveying zones for the polycarbonate pellets, the powder premix and the talc powder are located in the region of the outer shells 52 and 53.
A plasticized region comprised of various double and triple threaded kneading blocks and saw tooth blocks of various widths is located in the region of the housing 54.
The mixing zone consisting of kneading elements, toothed mixing elements and conveying elements is located in the region of the shells 56 to 58.
The pressurised zone and the nozzle plate with 6 holes downstream of it are located in the housing 59.
Polycarbonate pellets, powder premix and half of the talc powder were metered into hopper 50 via a commercially available gravity-type differential weighing scale and the other half of the talc powder was metered into the hopper (not shown) of the side feed unit via a commercially available gravity-type differential weighing scale in examples 10 and 11.
After cooling in a water bath, granulation was carried out in the form of strand granules.
The melt temperature measurements were made in examples 10 and 11 by inserting a thermocouple into the outgoing melt of one of the two central melt beams directly in front of the nozzle.
The experiments described in examples 12 to 14 (according to the invention) were carried out using a multiscrew extruder of the ringer xtruder RE 1XPV type from the company Extricom GmbH. The multi-screw extruder used had 12 screws each having a screw outer diameter of 18.7 mm, a DA/DI ratio of 1.74 and an L/D ratio of 35. A schematic configuration of the extruder used is shown in fig. 4. The multi-screw extruder had a housing consisting of 7 sections, in which 12 co-rotating intermeshing screws (not shown) were arranged.
The metering of the polycarbonate granulate and the powder premix takes place in examples 12 to 14 via the illustrated feed hopper 41 by means of the main feed in the housing 42. The dosing of the talc powder was carried out in example 12 via a side feed unit in the housing 45. The metered addition of the talc powder was carried out in examples 13 and 14 via two side feed units in the housing 45, wherein the side feed units in the housing 45 were arranged opposite each other. The metering of the respective half of the talc powder was carried out via each side feed unit in examples 13 and 14.
An exhaust port 49 is located in the housing portion 47 and is connected to an aspiration device (not shown).
The conveying zone for the polycarbonate pellet and powder premix is located in the region of the outer shell 43.
A plasticizing zone consisting of various double flighted kneading blocks of various widths is located in the region of the housing 44.
The mixing zone consisting of kneading elements, toothed blocks and conveying elements is located in the region of the shells 45 to 47.
The pressurised zone and the nozzle plate with 7 holes downstream thereof are located in the housing 48.
In examples 12 to 14 polycarbonate pellets and powder premix were metered into hopper 41 using a commercially available gravity gravimetric weigher. The metering of talc powder was carried out using a commercially available gravity gravimetric scale via a side feed unit in the housing 45 in example 12 and two commercially available gravity gravimetric scales via a side feed unit in the housing 45 in examples 13 and 14.
After cooling in a water bath, granulation was carried out in the form of strand granules.
The melt temperature measurement was performed by inserting a thermocouple into the outgoing melt of the central melt beam directly in front of the nozzle.
To evaluate the dispersing properties of the titanium dioxide powders in examples 1 to 4, the pressure upstream of the melt screen was measured at the beginning of the experiment, after constant torque was achieved and after 60 minutes, respectively, using a built-in pressure sensor. The pressure increase as shown in table 1 was calculated as follows:
pressure increase [ bar/min ] = (pressure after 60 minutes-pressure at start of experiment)/60 min.
The polycarbonate compositions produced in examples 5 to 14 were subsequently processed by injection molding to test specimens having a length and a width of 60 mm each and a thickness of 2 mm.
The injection molding process was carried out under the following process conditions characteristic of polycarbonates: the material temperature is 310 ℃, and the mold temperature is 90 ℃. The pellets of the polycarbonate moulding composition were predried at 110 ℃ within 4 hours before processing by injection moulding.
The puncture force and puncture deformation tests were carried out on the injection-molded test specimens from examples 5 to 14 at 23 ℃ in accordance with DIN EN ISO 6603-2: 2000. In each case 10 specimens were tested and the arithmetic mean was determined from these results.
For examples 1 to 8, the dispersing properties of the titanium dioxide powder were determined by visual evaluation of the extruded film. For this purpose, a film having a thickness of 150 μm was produced from the produced pellets of polycarbonate moulding compound by means of a film extrusion apparatus which essentially consists of a single-screw extruder and a downstream roller arrangement. The films were then photographed with a camera in a transmission light mode on a commercial light stand with the scale placed. The photographs were then visually evaluated (see fig. 5 to 12) and classified into performance grades 1 (excellent) to 6 (poor) (see table 2). The following applies to all figures 5 to 12, scale 1 graduation corresponding to 1 mm; incompletely dispersed titanium dioxide particles appear in the image as dark regions.
The notched impact strength of examples 9 to 14 was tested on injection-molded test specimens having dimensions of 80X 10X 3 mm by means of the impact bending test at 23 ℃ in accordance with DIN EN ISO 180/1A. In each case 10 specimens were tested and the arithmetic mean was determined from these results.
In examples 1 to 6, the moulding compound fed to the respective extruder consisted of the following mixture:
85% by weight of pellets of a linear polycarbonate based on bisphenol A, relative viscosity etarel= 1.32 (in CH)2Cl2Measured in a solvent at 25 ℃ and at a concentration of 0.5 g/100 ml) and
15% by weight of titanium dioxide powder (Kronos 2230 type from Kronos Titan).
In example 7, the moulding compound fed to the extruder consisted of the following mixture:
80% by weight of a linear polycarbonate based on bisphenol A, relative viscosity etarel= 1.32 (in CH)2Cl2Measured in a solvent at 25 ℃ and at a concentration of 0.5 g/100 ml) and
20% by weight of titanium dioxide powder (Kronos 2230 type from Kronos Titan).
In example 8, the moulding compound fed to the extruder consisted of the following mixture:
70% by weight of a linear polycarbonate based on bisphenol A, relative viscosity etarel= 1.32 (in CH)2Cl2Measured in a solvent at 25 ℃ and at a concentration of 0.5 g/100 ml) and
30% by weight of titanium dioxide powder (Kronos 2230 type from Kronos Titan).
In examples 9 to 12, the moulding compositions fed to the respective extruders consisted of the following mixtures:
80% by weight of a linear polycarbonate based on bisphenol A, relative viscosity etarel= 1.293 (in CH)2Cl2Measured in a solvent at 25 ℃ and at a concentration of 0.5 g/100 ml),
15% by weight of talc powder (HTP Ultra 5C type from Imi Fabi Co.) and
5% by weight of a powder mixture consisting of 80% by weight of a linear polycarbonate based on bisphenol A (relative viscosity. eta.,)rel= 1.32 (in CH)2Cl2Measured at 25 c and at a concentration of 0.5 g/100 ml) in a solvent) and 20 wt.% of a maleic anhydride grafted polyolefin copolymer (Hi-WAX 1105A type from Mitsui Chemicals).
In examples 10 and 13, the moulding compound fed to the respective extruder consisted of the following mixture:
75% by weight of a linear polycarbonate based on bisphenol A, relative viscosity etarel= 1.293 (in CH)2Cl2Measured in a solvent at 25 ℃ and at a concentration of 0.5 g/100 ml),
20% by weight of talc powder (HTP Ultra 5C type from Imi Fabi Co.) and
5% by weight of a powder mixture consisting of 80% by weight of a linear polycarbonate based on bisphenol A (relative viscosity. eta.,)rel= 1.32 (in CH)2Cl2Measured at 25 c and at a concentration of 0.5 g/100 ml) in a solvent) and 20 wt.% of a maleic anhydride grafted polyolefin copolymer (Hi-WAX 1105A type from Mitsui Chemicals).
In examples 11 and 14, the moulding compositions fed to the respective extruders consisted of the following mixtures:
65% by weight of a linear polycarbonate based on bisphenol A, relative viscosity etarel= 1.293 (in CH)2Cl2Measured in a solvent at 25 ℃ and at a concentration of 0.5 g/100 ml),
30% by weight of talc powder (HTP Ultra 5C type from Imi Fabi Co.) and
5% by weight of a powder mixture consisting of 70% by weight of a linear polycarbonate based on bisphenol A (relative viscosity. eta.,)rel= 1.32 (in CH)2Cl2Measured at 25 c and at a concentration of 0.5 g/100 ml) in a solvent) and 30 wt.% of a maleic anhydride grafted polyolefin copolymer (Hi-WAX 1105A type from Mitsui Chemicals).
Comparative examples 1 to 3
Comparative examples 1 and 3 differ in the number of revolutions of the extruder. The extruder revolutions were 3001/min in example 1 and twice at the same throughput of 580 kg/h in example 3. As can be seen from the much lower pressure increase upstream of the melt screen (see table 1) and the reduction in the number of undispersed titanium dioxide particles (see fig. 5 (example 1) compared to fig. 6 (example 2)), the increase in the number of revolutions brings about a significantly improved dispersion. At the higher revolutions in example 3, however, the melt temperature was simultaneously increased by 34 ℃, which promotes the polymer decomposition in a manner known to the person skilled in the art.
Comparative examples 1 and 2 differ only in the metering position of the titanium dioxide powder. In example 1 titanium dioxide powder was added to the feed hopper 1, while in example 2 after melting it was added to the polycarbonate melt via a side feed unit in the housing 8. As is apparent from table 1, the addition of the titanium dioxide powder after melting in example 2 resulted in a significantly greater increase in pressure upstream of the melt screen, which is an indication of poorer dispersion, and this is also confirmed in fig. 7, which shows a greater number of titanium dioxide particles that were poorly dispersed. In contrast, the number of large titania particles in fig. 5 (example 1) is significantly lower.
Example 4 (according to the invention)
The object of example 4 according to the invention is to achieve a titanium dioxide dispersion which is at least comparable to that of comparative example 3, but at a significantly lower melt temperature. The apparatus and throughput and the number of revolutions of the process according to the invention were selected for this purpose, which resulted in a comparable pressure increase upstream of the melt screen as in comparative example 3. In both examples 1 and 3 and in example 4, titanium dioxide was added to the extruder via feed hoppers 1 and 14, respectively.
A comparison of example 4 according to the invention with examples 1 and 3 not according to the invention shows that a significantly better dispersion of the titanium dioxide particles can be achieved with the process according to the invention, while a lower melt temperature is achieved. This is evident on the one hand from the fact that the pressure increase in example 4 is as high as in example 3, but the melt temperature is 35 ℃ lower (see table 1). It is on the other hand apparent from fig. 8 that the number of poorly dispersed titanium dioxide particles is comparable to that of example 3 (fig. 6), but lower than that of example 1 (fig. 5).
Comparative example 5
In comparative example 5, titanium dioxide powder was added to a co-rotating twin screw extruder via feed hopper 28. The dispersion property of titanium dioxide was determined by visually observing the size and the number of incompletely dispersed titanium dioxide particles in the film produced as described above (see fig. 9). Furthermore, the multiaxial mechanical properties were determined by means of the abovementioned puncture test at 23 ℃ in accordance with DIN EN ISO 6603-2: 2000.
Example 6 (according to the invention)
In example 6 according to the invention, titanium dioxide powder was added to the casing 45 after the polycarbonate had melted. This mode of the process results in comparative example 2 in a significantly poorer dispersion of the titanium dioxide particles than the addition to the first extruder housing (see pressure increase in table 1 and resulting particle size in fig. 7).
The puncture test on the test specimen from example 6 according to the invention shows that the mathematical product of the maximum deformation and the maximum force is significantly higher than in comparative example 5 (see table 1). Visual evaluation of the film also revealed that the dispersion of titanium dioxide particles was better in example 6 according to the invention than in example 5. This demonstrates that the process according to the invention leads to improved dispersion of the titanium dioxide particles and better mechanical properties even in the case of non-optimal addition of titanium dioxide powder (i.e. after melting of the polycarbonate).
Example 6 according to the invention simultaneously achieves a melt temperature which is 44 ℃ lower than that of comparative example 5 (see table 1).
Example 7 (according to the invention)
In example 7, 20% by weight of titanium dioxide powder was added to the housing 45 after the polycarbonate had melted. Despite the non-optimal location of the addition of titanium dioxide and the simultaneously greater amount of titanium dioxide compared to comparative example 5, which is known to lead to embrittlement of the polycarbonate moulding compound, only a slightly lower mathematical product of the maximum deformation and the maximum force is observed (see table 1) than in comparative example. Visual evaluation of the titanium dioxide particle dispersion using films shows that the films made from the polycarbonate moulding compound according to the invention from example 7 (see FIG. 11) have a better titanium dioxide dispersion than the films made from the polycarbonate moulding compound of comparative example 5 (see FIG. 9). Even at higher titanium dioxide ratios, the melt temperature was 42 ℃ lower than that of comparative example 5 (see table 1).
Example 8 (according to the invention)
In example 8, 30% by weight of titanium dioxide powder was added to the housing 45 after the polycarbonate had melted. Despite the non-optimal location of the addition of titanium dioxide and the simultaneously greater amount of titanium dioxide compared to comparative example 5, which is known to lead to embrittlement of the polycarbonate moulding compound, only a slight reduction in the mathematical product of the maximum deformation and the maximum force is found compared to what is known from comparable products (see table 1). Visual evaluation of the titanium dioxide particle dispersion using films shows that the films made from the polycarbonate moulding compounds according to the invention from example 8 (see FIG. 12) have almost as good a titanium dioxide dispersion as the films made from the polycarbonate moulding compounds of comparative example 5 (see FIG. 9). Even at double the titanium dioxide ratio, the melt temperature was 41 ℃ lower than that of comparative example 5 (see table 1).
Comparative example 9
In comparative example 9, talc powder was added to a co-rotating twin screw extruder via a side feed unit in housing 55. The dispersion properties were determined on the basis of the notched impact toughness using the notched impact flexural strength test described above at 23 ℃ in accordance with DIN EN ISO 180/1A and on the basis of the multiaxial mechanical properties using the puncture test described above at 23 ℃ in accordance with DIN EN ISO 6603-2: 2000.
Comparative examples 10 and 11
In comparative examples 10 and 11, half of the talc powder was added to the co-rotating twin-screw extruder via feed hopper 50 and the other half of the talc powder was added via a side feed unit in housing 55, respectively. Comparative examples 10 and 11 differ in the proportion of talc powder in the formulation. 20 wt% talc was added to the co-rotating twin screw extruder in example 10, and 30 wt% talc was added to the co-rotating twin screw extruder in example 11. The dispersion properties were determined on the basis of the notched impact toughness using the notched impact flexural strength test described above at 23 ℃ in accordance with DIN EN ISO 180/1A and on the basis of the multiaxial mechanical properties using the puncture test described above at 23 ℃ in accordance with DIN EN ISO 6603-2: 2000.
Example 12 (according to the invention)
In example 12, 15 wt% talc powder was added to the ring extruder via a side feed unit in housing 45 after the polycarbonate was melted. Compared to comparative example 9, significantly better mechanical properties were achieved, although the lower energy input is seen from the lower 5 ℃ melt temperature according to the examples of the invention (see table 1). The mathematical product of the maximum deformation and the maximum force is 7.4% higher in example 12 according to the invention than in comparative example 9, and the notched impact toughness is even 113% higher (see table 1).
Example 13 (according to the invention)
In example 13, 10 wt% talc powder was added to the ring extruder via feed hopper 41 and another 10 wt% was added via the side feed unit in housing 45 after the polycarbonate was melted. Compared to comparative example 10, significantly better mechanical properties were achieved, although the lower energy input is seen from the lower 8 ℃ melt temperature according to the examples of the invention (see table 1). The mathematical product of the maximum deformation and the maximum force is 23% higher in example 13 according to the invention than in comparative example 10, and the notched impact toughness is even 197% (see table 1).
Example 14 (according to the invention)
In example 14, 15 wt% talc powder was added to the ring extruder via feed hopper 41 and an additional 15 wt% was added via the side feed unit in housing 45 after the polycarbonate was melted. Compared to comparative example 11, significantly better mechanical properties were achieved, although the lower energy input is seen from the lower 38 ℃ melt temperature according to the examples of the invention (see table 1). The mathematical product of the maximum deformation and the maximum force is 1116% higher in example 14 according to the invention than in comparative example 10, and the notched impact strength is even 336% (see table 1).