Method for manufacturing a molding formulation having improved surface characteristics

Abstract

The present invention relates to a method for producing a molding composition having improved surface properties. The present invention relates to a molding composition comprising a polycarbonate and at least one reinforcing filler selected from the group comprising titanium dioxide (TiO2), talc (Mg3Si4O10(OH)2), dolomite CaMg[CO3]2, kaolinite Al4[(OH)8|Si4O10] and wollastonite Ca3[Si3O9], preferably selected from the group comprising titanium dioxide (TiO2) and talc (Mg3Si4O10(OH)2). According to the present invention, the total amount of the reinforcing filler is 3 to 20 wt%, preferably 4.5 to 15 wt%, with respect to the total mass of the molding composition, and a molding composition having improved properties is produced using at least one masterbatch prepared according to the present invention.

Description

Technology Field

[0001] The present invention relates to the manufacture of a molding formulation having improved properties. The present invention further relates to, in particular, preferably titanium dioxide (TiO2) and talc (Mg3Si4O2). 10 (OH)2), Dolomite CaMg[CO3]2, Kaolinite Al4[(OH)8|Si4O 10 ], and selected from the group comprising wollastonite Ca3[Si3O9], more preferably titanium dioxide (TiO2) and talc (Mg3Si4O2) 10 The present invention relates to the preparation of a molding formulation comprising at least one reinforcing filler selected from the group including (OH)2) and polycarbonate. The total content of the reinforcing filler is, in each case, 3% to 20% by weight, preferably 4.5% to 15% by weight, based on the total mass of the molding formulation. A molding formulation having improved surface properties is prepared using at least one masterbatch prepared according to the present invention. Specific details for implementing the invention

[0002] The masterbatch prepared according to the present invention is preferably titanium dioxide (TiO2) and talc (Mg3Si4O2). 10 (OH)2), Dolomite CaMg[CO3]2, Kaolinite Al4[(OH)8|Si4O 10 ], and selected from the group comprising wollastonite Ca3[Si3O9], more preferably titanium dioxide (TiO2) and talc (Mg3Si4O2) 10 It comprises at least one reinforcing filler selected from the group including (OH)2) and polycarbonate. The total content of the reinforcing filler in the masterbatch is, in each case, 30% to 70% by weight, preferably 35% to 65% by weight, more preferably 40% to 60% by weight, based on the total mass of the masterbatch.

[0003] The masterbatch prepared according to the present invention preferably contains only one reinforcing filler, namely only titanium dioxide (TiO2) or only talc (Mg3Si4O2). 10 (OH)2) or only dolomite CaMg[CO3]2 or only kaolinite Al4[(OH)8|Si4O 10 ] or only wollastonite Ca3[Si3O9], preferably only titanium dioxide (TiO2) or only talc (Mg3Si4O 10 It includes only (OH)2). With respect to this single reinforcing filler, the masterbatch used in each case contains a higher content of reinforcing filler than the respective molding formulation prepared using said masterbatch.

[0004] Nevertheless, the total content of reinforcing fillers in the molded formulation may be higher than the total content of reinforcing fillers in the masterbatch, particularly when the masterbatch contains only one reinforcing filler, because the molded formulation may contain multiple reinforcing fillers. The total content of reinforcing fillers in the molded formulation can be achieved by adding various masterbatches each containing various reinforcing fillers and / or by adding additional reinforcing fillers, particularly by adding additional reinforcing fillers.

[0005] A masterbatch can be obtained by mixing polycarbonate, at least one reinforcing filler, and optionally other masterbatch components using a continuous single-shaft kneader according to the present invention. In particular, the method according to the present invention

[0006] (1) A step of adding polycarbonate and at least one reinforcing filler to a continuous single-shaft kneader;

[0007] (2) A step of mixing polycarbonate and at least one reinforcing filler using a continuous single-shaft kneader

[0008] Includes

[0009] Preferably, only one reinforcing filler is added in step (1). It is also possible to add other masterbatch components in step (1) or step (2) and to mix them in step (2). Steps (1) and (2) can be performed sequentially or simultaneously.

[0010] Polycarbonate, reinforcing fillers, and optionally other masterbatch components can be added to a continuous single-shaft kneader simultaneously or sequentially. In particular, at least one reinforcing filler can be added before melting the polycarbonate, after melting the polycarbonate, or both before and after melting the polycarbonate.

[0011] The masterbatch may additionally include other masterbatch components. The content of other masterbatch components in a masterbatch comprising polycarbonate and at least one reinforcing filler is, in each case, 0% to 5% by weight, preferably 0% to 4% by weight, more preferably 0% to 3% by weight, based on the total mass of the molded compound. Depending on the total content of at least one reinforcing filler and the content of other masterbatch components, the polycarbonate content in the masterbatch according to the present invention is, in each case, 70% to 25% by weight, preferably 65% ​​to 31% by weight, more preferably 59.5% to 37% by weight, based on the total mass of the masterbatch. The sum of all components of the masterbatch is 100% by weight.

[0012] These other masterbatch components include, for example, other fillers conventional in polycarbonate masterbatches, other thermoplastics, for example, acrylonitrile-butadiene-styrene copolymer, styrene-acrylonitrile copolymer, or also polyester, or other additives, such as UV stabilizers, IR stabilizers, heat stabilizers, antistatic agents, dyes, and pigments, added in conventional amounts; Optionally, release properties, flow properties, and / or flame retardancy may be further improved by adding external release agents, flow agents, and / or flame retardants (e.g., alkyl and aryl phosphites, phosphates, and phosphanes, low molecular weight carboxylic acid esters, halogen compounds, salts, chalk, quartz powder, glass fibers, carbon fibers, pigments, and combinations thereof). Such compounds are described, for example, in WO 99 / 55772, pp. 15–25, and in the literature “Plastics Additives”, R. Gaechter and H. Mueller, Hanser Publishers 1983). Carboxylic acid anhydride-modified alpha-olefin polymers, in particular maleic anhydride-modified alpha-olefin polymers, are preferred as stabilizers. Such carboxylic acid anhydride-modified alpha-olefin polymers are known, for example, from WO 2018037037A1. Other masterbatch components may include one or more In the case of thermoplastic plastics, their total content in the masterbatch is 3.0 weight% or less, preferably 2.5 weight% or less, more preferably 2.0 weight% or less. If the proportion of thermoplastic plastics other than polycarbonate is higher, the usefulness of the masterbatch is too limited.

[0013] The aforementioned polyester and the polyester carbonate further described above should be distinguished from one another. For the purposes of the present invention, the polyesters are those described in paragraphs

[0131] to

[0138] of US 2014 / 357769 A1. The proportion of polyester in the masterbatch is 0.9 wt% or less, preferably 0.5 wt% or less, more preferably 0.2 wt% or less, particularly preferably 0.1 wt% or less, and very particularly preferably 0 wt% to 0.1 wt%. Most preferably, the proportion of polyester in the masterbatch is 0 wt%.

[0014] Masterbatches are, in principle, derived from prior art, for example [1] ([1] = Klemens Kohlgrueber: The co-rotating twin-screw extruder, 2nd revised and expanded edition, Hanser Verlag, Munich 2016, p. 76 ff. It has been announced from ).

[0015] For the purposes of the present invention, a masterbatch is understood to mean a solid mixture comprising at least one polymer and at least one reinforcing filler, wherein the masterbatch may exist in pellets, powder or other forms and may be used in the manufacture of polymer molding formulations.

[0016] A masterbatch containing polycarbonate is also referred to as a polycarbonate masterbatch below.

[0017] In addition, a polymer molding formulation, for example, a molding formulation including a polycarbonate of one of these polymer molding formulations, is prepared by mixing an additive, for example, a filler, to enable the polymer molding formulation to achieve a desired characteristic profile, which is also from the prior art, for example [1] ([1] = Klemens Kohlgrueber: The co-rotating twin-screw extruder, 2nd revised and expanded edition, Hanser Verlag, Munich 2016, p. 47 ff.It is known from ). This manufacturing, also referred to as formulation, is generally carried out in a twin-screw extruder. It is particularly desirable to disperse the filler as best as possible in the polymer molding formulation, that is, to grind and distribute the filler as best as possible in the polymer molding formulation. As the total content of the filler to be dispersed in the polymer molding formulation increases and as it becomes necessary to disperse the filler better, that is, grind and distribute it in the polymer molding formulation, formulation becomes increasingly difficult.

[0018] A molding formulation containing polycarbonate is also referred to as a polycarbonate molding formulation below.

[0019] According to the present invention, at least one reinforcing filler is introduced into a polycarbonate molding formulation using a masterbatch prepared according to the present invention. A polycarbonate molding formulation prepared in this manner comprises polycarbonate and at least one reinforcing filler. The total content of the reinforcing filler is, in each case, 3% to 20% by weight, preferably 4.5% to 15% by weight, based on the total mass of the molding formulation.

[0020] The molding compound may also include other molding compound components. The content of other molding compound components in the molding compound comprising polycarbonate and at least one reinforcing filler is, in each case, 0% to 61% by weight, preferably 0% to 54.5% by weight, more preferably 0% to 25% by weight, based on the total mass of the molding compound. Depending on the total content of at least one reinforcing filler and the content of other molding compound components, the content of polycarbonate in the molding compound according to the present invention is, in each case, 97% to 36% by weight, preferably 95.5% to 41% by weight, based on the total mass of the molding compound. The sum of all components of the molding compound is 100% by weight. For example, a polycarbonate molding formulation according to the present invention containing 15 weight% of reinforcing filler may additionally contain 82 weight% of polycarbonate and 3 weight% of other molding formulation components, or a polycarbonate molding formulation according to the present invention containing 15 weight% of reinforcing filler may additionally contain 65 weight% of polycarbonate and 20 weight% of other molding formulation components, but the present invention is not limited thereto.

[0021] In addition, for example, a polycarbonate molding formulation according to the present invention containing 4.5 weight% of reinforcing filler may additionally contain 92.5 weight% of polycarbonate and 3 weight% of other molding formulation components, or a polycarbonate molding formulation according to the present invention containing 4.5 weight% of reinforcing filler may additionally contain 65.5 weight% of polycarbonate and 30 weight% of other molding formulation components, but the present invention is not limited thereto.

[0022] According to the present invention, such a molding formulation can be obtained by further processing the polycarbonate masterbatch obtained in steps (1) and (2) as follows:

[0023] (3) A step of adding the polycarbonate masterbatch and polycarbonate obtained in step (2) to a blending unit;

[0024] (4) A step of mixing the polycarbonate masterbatch and polycarbonate obtained in step (2) using a mixing unit.

[0025] Steps (3) and (4) can be performed sequentially or simultaneously.

[0026] Optionally, additional reinforcing fillers may be added in step (3) and inter-mixed in step (4). These additional reinforcing fillers may be the same as those present in the masterbatch, or they may be different reinforcing fillers from those present in the masterbatch. The reinforcing filler additionally added in step (3) is preferably different from that present in the masterbatch.

[0027] In addition, it is possible to arbitrarily add other molding mixture components in step (3) and mix them together in step (4).

[0028] The compounding unit is preferably selected from the group consisting of a continuous single-shaft kneader, a multi-shaft extruder, in particular a twin-screw extruder or a ring extruder, a planetary roller extruder, a ram kneader, and an internal mixer. The compounding unit is particularly preferably a twin-screw extruder or a ring extruder or a planetary roller extruder, and very particularly preferably a co-rotating twin-screw extruder.

[0029] Improved dispersion of fillers, particularly reinforcing fillers, in polymer molding formulations also has the effect of resulting in improved properties, particularly improved surface properties, of the molding formulation.

[0030] For example, in a given twin-screw extruder, the energy input to the polymer molding formulation must be increased to achieve the highest possible total filler content, particularly improved dispersion of reinforcing fillers. However, this causes the temperature of the polymer molding formulation to rise during mixing in the twin-screw extruder, and the higher the energy input, the greater the temperature rise. Furthermore, this can lead to thermal damage to the polymer molding formulation. Additionally, this may cause the polymer molding formulation to yellow, stain, or undergo other undesirable changes.

[0031] Since the aforementioned thermal damage must generally be avoided, improved dispersion is not achieved, the total content of fillers, particularly reinforcing fillers, is not increased, or both. However, in rare cases, thermal damage or poor dispersion, or both, are permitted. Nevertheless, it is impossible to obtain polymer molding formulations with improved surface characteristics in this manner.

[0032] Furthermore, it was found that using a twin-screw extruder with a length-to-diameter ratio (L / D ratio) greater than that of the twin-screw extruder mentioned at the beginning does not solve the problem, because when the desired improved dispersion is to be achieved at a desired high total content of fillers, particularly reinforcing fillers, the thermal stress applied to the polymer molding formulation becomes undesirably high even in the case of a twin-screw extruder with a larger L / D ratio. This is because increasing the L / D ratio of a twin-screw extruder under otherwise unchanged conditions causes the temperature of the polymer molding formulation to be extruded to rise by about 10°C to 20°C for an additional length of the twin-screw extruder corresponding to four times the outer diameter of the screw element cleaning the inner wall of the twin-screw extruder. Therefore, a polymer molding formulation with improved surface characteristics cannot be obtained in this manner.

[0033] In addition, when a polycarbonate molding formulation having a high proportion of reinforcing filler is manufactured by the formulation, it faces the problem described above.

[0034] Therefore, the object of the present invention is to provide a method for manufacturing an improved polycarbonate molding formulation containing a reinforcing filler.

[0035] The polycarbonate molding formulation according to the present invention will have particularly improved surface characteristics, particularly fewer defects, and especially fewer defects in the form of surface ridges or depressions caused by incompletely dispersed reinforcing filler particles.

[0036] Surprisingly, the above objective was found to be achieved by a method of producing a polycarbonate molding compound using a polycarbonate masterbatch comprising polycarbonate and a reinforcing filler, blended using a continuous single-shaft kneader. The total content of the reinforcing filler in the polycarbonate masterbatch is, in each case, 30% to 70% by weight, preferably 35% to 65% by weight, more preferably 40% to 60% by weight, based on the total mass of the masterbatch, and the total content of the reinforcing filler in the polycarbonate molding compound is, in each case, 3% to 20% by weight, preferably 4.5% to 15% by weight, based on the total mass of the polycarbonate molding compound.

[0037] With respect to one of these reinforcing fillers, the polycarbonate masterbatch used to produce the polycarbonate molding compound in each case has a higher reinforcing filler content than the polycarbonate molding compound produced using this polycarbonate masterbatch in each case. The content of one reinforcing filler in the polycarbonate masterbatch is preferably 1.2 to 140 times, preferably 1.5 to 100 times, and more preferably 2 to 10 times higher than the content of one reinforcing filler in the molding compound.

[0038] The method according to the present invention provides an improved polycarbonate molding formulation. Although the inventors do not intend to be bound by any particular scientific theory, it can be reasonably inferred that the improved properties of the polycarbonate molding formulation prepared according to the present invention are due to a polycarbonate masterbatch having likewise improved properties, and that said improved properties are particularly due to the improved dispersion of reinforcing filler(s) in the masterbatch.

[0039] The means used to achieve the objective are particularly remarkable, because a continuous single-shaft kneader was not previously known to have a specific dispersion mixing effect, and thus, significantly improved dispersion and the resulting improvements were not expected when using it. The dispersion mixture is characterized not only by the particles being distributed by volume but also by the particles being particularly pulverized.

[0040] For the purposes of the present invention, reinforcing filler is understood to mean a mineral filler suitable for increasing the stiffness of a polycarbonate molded compound prepared according to the present invention. The reinforcing filler is preferably titanium dioxide (TiO2) and talc (Mg3Si4O2). 10 (OH)2), Dolomite CaMg[CO3]2, Kaolinite Al4[(OH)8|Si4O 10], and selected from the group comprising wollastonite Ca3[Si3O9], preferably titanium dioxide (TiO2) and talc (Mg3Si4O2 10 It is selected from the group including (OH)2). This applies equally to masterbatch molding formulations and polycarbonate molding formulations.

[0041] In particular, the method according to the present invention provides a polycarbonate molding formulation having improved surface characteristics, particularly fewer defects, particularly fewer defects in the form of surface ridges or depressions caused by incompletely dispersed reinforcing filler particles. Incompletely dispersed reinforcing filler particles can be determined, for example, by visual analysis of an image of a molded article made from the molding formulation according to the present invention; and the particle size distribution of the incompletely dispersed reinforcing filler particles can be evaluated by classification;

[0042] This type of polycarbonate molding compound prepared according to the present invention has superior, i.e., improved, characteristics compared to a polycarbonate molding compound prepared by a method according to the prior art that contains the same components as the polycarbonate molding compound prepared according to the present invention in the same proportion.

[0043] For the purposes of the present invention, the term "molded article" is understood to mean an article resulting from further processing of a molding composition. Accordingly, not only an article that can be obtained, for example, by injection molding from a molding composition, but also a film or sheet that can be obtained by extrusion of a molding composition should be considered a molded article.

[0044] The titanium dioxide (TiO2) used preferably has a particle size d of 0.1 μm to 5 μm, preferably 0.3 to 3 μm. 50It is a rutile modified product having [the following]. Examples of titanium dioxide that can be used according to the present invention are selected from the commercially available products Kronos 2230 titanium dioxide and Kronos 2233 titanium dioxide; the manufacturer of both products is Kronos Titan GmbH Leverkusen.

[0045] Talc (Mg3Si4O2) 10 (OH)2) preferably has a particle size d of 0.1 μm to 10 μm, preferably 0.3 to 3 μm. 50 It is used with. Talc that can be used includes, for example, commercially available products such as Jetfine 3CA from Imerys Talc (Luzenac Europe SAS) or HTP Ultra 5C talc from IMI Fabi SpA.

[0046] Particle size d 50 In each case, it is based on mass and was determined according to ISO 1333 17-3 using a Sedigraph 5100 from Micrometrics of Germany.

[0047] A mixture of titanium dioxide and talc can be used in any desired mixing ratio. In each case, the mixing ratio of titanium dioxide to talc is preferably 1:60 to 1:1, preferably 1:30 to 1:5, based on mass.

[0048] Each mineral particle constituting the reinforcing filler preferably has an aspect ratio of 1:1 to 1:7.

[0049] For the purposes of the present invention, "polycarbonate" is understood to mean both homopolycarbonate and copolycarbonate. Polycarbonates may be linear or branched in a familiar manner. Mixtures of polycarbonates may also be used according to the present invention.

[0050] In the polycarbonate used according to the present invention, a proportion of carbonate groups of 80 mol% or less, preferably 20 mol% to 50 mol% or less, can preferably be replaced by aromatic dicarboxylic acid ester groups. Polycarbonates of this kind that include both acid moiety from carbonic acid and, preferably, acid moiety from aromatic dicarboxylic acid in their molecular chains are referred to as aromatic polyester carbonates.

[0051] The substitution of carbonate groups by aromatic dicarboxylic acid ester groups occurs essentially stoichiometrically and also quantitatively, which means that the molar ratio of the coreactant is reflected in the finished polyester carbonate. Aromatic dicarboxylic acid ester groups can be incorporated randomly or in a block manner.

[0052] Thermoplastic polycarbonates including thermoplastic polyester carbonates have an average molecular weight Mw determined by GPC (gel-permeation chromatography performed in methylene chloride using polycarbonates as standards), of 15 kg / mol to 50 kg / mol, preferably 20 kg / mol to 35 kg / mol, more preferably 23 kg / mol to 33 kg / mol.

[0053] Preferred aromatic polycarbonates and aromatic polyester carbonates are prepared in a known manner from diphenols, carbonates or carbonate derivatives, and, in the case of polyester carbonates, preferably aromatic dicarboxylic acids or dicarboxylic acid derivatives, optionally chain terminators and branching agents.

[0054] Detailed information regarding the manufacture of polycarbonates has been presented in numerous patent specifications over the past 40 years or so. Here, for example, references are cited in the literature (Schnell, "Chemistry and Physics of Polycarbonates", Polymer Reviews, volume 9, Interscience Publishers, New York, London, Sydney 1964) and the literature (D. Freitag, U. Grigo, PR Mueller, H. Nouvertn , Bayer AG, "Polycarbonates" in Encyclopedia of Polymer Science and Engineering, volume 11, second edition, 1988, pages 648-718, and finally U. Grigo, K. Kirchner and PR Mueller "Polycarbonate" [Polycarbonates] in Becker / Braun, Kunststoff-Handbuch [Plastics Handbook], volume 3 / 1, "Polycarbonate, Polyacetale, Polyester, Celluloseester" [Polycarbonates, polyacetals, polyesters, cellulose esters], Carl Hanser Verlag Munich, Vienna 1992, pages 117-299).

[0055] Aromatic polycarbonates and polyester carbonates are prepared, for example, by the reaction of a diphenol with a carbonyl halide, preferably phosgene, and / or an aromatic dicarbonyl dihalide, preferably benzenedicarbonyl dihalide, by an interfacial process, optionally using a chain terminator and optionally a trifunctional or excess trifunctional branching agent, wherein the preparation of polyester carbonates is achieved by replacing a portion of the carbonate derivatives with an aromatic dicarboxylic acid or a derivative of a dicarboxylic acid, in particular by replacing them with aromatic dicarboxylic acid ester structural units according to the proportion of carbonate structural units to be replaced in the aromatic polycarbonate. Preparation is also possible through a melt polymerization process by the reaction of a diphenol with, for example, diphenyl carbonate.

[0056] Dihydroxyaryl compounds suitable for the manufacture of polycarbonate are those of the following chemical formula (1).

[0057] HO-Z-OH (1),

[0058] Here

[0059] Z is an aromatic radical having 6 to 30 carbon atoms, which may contain one or more aromatic rings, may be substituted, and may contain an aliphatic or cycloaliphatic radical or an alkylaryl or heteroatom as a crosslinking element.

[0060] In chemical formula (1), Z preferably represents a radical of chemical formula (2) below.

[0061]

[0062] Here

[0063] R6 and R7 independently represent H, C1 to C18 alkyl, C1 to C18 alkoxy, halogen, e.g., Cl or Br, or in each case optionally substituted aryl or aralkyl, preferably H or C1 to C12 alkyl, particularly preferably H or C1 to C8 alkyl, very particularly preferably H or methyl, and

[0064] X represents a single bond, -SO2-, -CO-, -O-, -S-, C1- to C6 alkylene, C2 to C5 alkylidene, or C5 to C6 cycloalkylidene (which may be substituted by C1 to C6 alkyl, preferably methyl or ethyl), or represents a C6 to C12 arylene that may optionally be fused to an additional aromatic ring containing a heteroatom.

[0065] It is preferable that X represents a single bond, C1 to C5 alkylene, C2 to C5 alkylidene, C5 to C6 cycloalkylidene, -O-, -SO-, -CO-, -S-, -SO2-, or a radical of the following formula (2a).

[0066]

[0067] Examples of diphenols suitable for the manufacture of polycarbonates include hydroquinone, resorcinol, dihydroxydiphenyl, bis(hydroxyphenyl)alkanes, bis(hydroxyphenyl)cycloalkanes, bis(hydroxyphenyl)sulfides, bis(hydroxyphenyl)ethers, bis(hydroxyphenyl)ketones, bis(hydroxyphenyl)sulfones, bis(hydroxyphenyl)sulfoxides, α,α'-bis(hydroxyphenyl)diisopropylbenzene, phthalimidins derived from derivatives of isatin or derivatives of phenolphthalein, and their ring-alkylated, ring-arylated, and ring-halogenated compounds.

[0068] Preferred bisphenols are 4,4'-dihydroxydiphenyl, 2,2-bis(4-hydroxyphenyl)-1-phenylpropane, 1,1-bis(4-hydroxyphenyl)phenylethane, 2,2-bis(4-hydroxyphenyl)propane (Bisphenol A (BPA)), 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, 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 (bisphenol TMC (BPTMC)), and also bisphenol of the following formulas (IV) to (VI).

[0069]

[0070] Here, R' represents a C1 to C4 alkyl, aralkyl, or aryl, preferably methyl or phenyl, in each case.

[0071] Particularly preferred bisphenols are 4,4'-dihydroxydiphenyl, 1,1-bis(4-hydroxyphenyl)phenylethane, 2,2-bis(4-hydroxyphenyl)propane (bisphenol A (BPA)), 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane, 1,1-bis(4-hydroxyphenyl)cyclohexane and 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane (bisphenol TMC (BPTMC)), and dihydroxy compounds of formulas (IV), (V) and (VI) (where R' represents a C1 to C4 alkyl, aralkyl, or aryl, preferably methyl or phenyl, in each case).

[0072] These and other suitable diphenols are, for example, US-A3 028 635, US-A2 999 825, US-A3 148 172, US-A2 991 273, US-A3 271 367, US-A4 982 014, and US-A2 999 846, DE-A1 570 703, DE-A2 063 050, DE-A2 036 052, DE-A2 211 956, and DE-A3 832 396, FR-A1 561 518, the paper (“H. Schnell, Chemistry and Physics of Polycarbonates, Interscience Publishers, New York 1964”) and also JP-A It is described in 62039 / 1986, JP-A 62040 / 1986, and JP-A 105550 / 1986.

[0073] In the case of homopolycarbonates, only one diphenol is used, while in the case of copolycarbonates, two or more diphenols are used. The diphenols used, like all other chemicals and auxiliaries added to the synthesis process, can be contaminated by impurities generated during their synthesis, handling, and storage. However, it is desirable to use raw materials of the highest possible purity.

[0074] In particular, the polycarbonate according to the present invention is composed only of atoms selected from one or more of the elements carbon (C), hydrogen (H), oxygen (O), nitrogen (N), sulfur (S), chlorine (Cl), and bromine (Br).

[0075] Polycarbonate-polyorganosiloxane copolymers are preferably excluded as copolycarbonates.

[0076] Examples of suitable carbonate derivatives are phosgene or diphenyl carbonate.

[0077] Suitable chain terminations that can be used in the manufacture of polycarbonates are monophenols. Examples of suitable monophenols include phenol itself, alkylphenols such as cresol, p-tert-butylphenol, cumylphenol, and mixtures thereof.

[0078] A preferred chain terminator is a linear or branched phenol monosubstituted or polysubstituted by an unsubstituted C1 to C30 alkyl radical or by a tert-butyl group. Particularly preferred chain terminators are phenol, cumylphenol, and / or p-tert-butylphenol.

[0079] The amount of chain terminator used is preferably 0.1 to 5 mol% based on the mole of diphenol used in each case. The chain terminator may be added before, during, or after the reaction with the carbonate derivative.

[0080] Suitable branching agents are trifunctional or greater than trifunctional compounds known in polycarbonate chemistry, in particular those having three or more than three phenolic OH groups.

[0081] Examples of suitable branching agents are 1,3,5-tri(4-hydroxyphenyl)benzene, 1,1,1-tri(4-hydroxyphenyl)ethane, tri(4-hydroxyphenyl)phenylmethane, 2,4-bis(4-hydroxyphenylisopropyl)phenol, 2,6-bis(2-hydroxy-5'-methylbenzyl)-4-methylphenol, 2-(4-hydroxyphenyl)-2-(2,4-dihydroxyphenyl)propane, tetra(4-hydroxyphenyl)methane, tetra(4-(4-hydroxyphenylisopropyl)phenoxy)methane, 1,4-bis((4',4"-dihydroxytriphenyl)methyl)benzene, and 3,3-bis(3-methyl-4-hydroxyphenyl)-2-oxo-2,3-dihydroindole.

[0082] The amount of branching agent for optional use is preferably 0.05 mol% to 2.00 mol% based on the mole of diphenol used in each case.

[0083] The branching agent can be initially introduced as an aqueous alkaline phase along with diphenol and a chain terminator, or added as a solution in an organic solvent prior to phosgenation. In the case of the ester exchange process, the branching agent is used together with diphenol.

[0084] Particularly preferred polycarbonates are homopolycarbonates based on bisphenol A, homopolycarbonates based on 1,3-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, and copolycarbonates based on monomers selected from the group comprising, on one hand, monomer bisphenol A or on the other hand, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane and bisphenol of the following formulas (IV) to (VI).

[0085]

[0086] Here, R' represents a C1 to C4 alkyl, aralkyl, or aryl, preferably methyl or phenyl, in each case.

[0087] Preferred manufacturing methods for polycarbonates used according to the present invention, including polyester carbonates, are known interfacial processes and known melt transesterification processes (see, for example, WO 2004 / 063249 A1, WO 2001 / 05866 A1, WO 2000 / 105867, US 5,340,905 A, US 5,097,002 A, US-A 5,717,057 A).

[0088] An aromatic polycarbonate based on bisphenol A is most preferred as a polycarbonate.

[0089] Titanium dioxide (TiO2) and / or talc (Mg3Si4O2) 10 (OH)2), Dolomite CaMg[CO3]2, Kaolinite Al4[(OH)8|Si4O 10In addition to ] and / or wollastonite Ca3[Si3O9], it is also possible to add additional molding formulation components to the polycarbonate molding formulation according to the present invention.

[0090] The content of other molding compound components in the polycarbonate molding compound prepared according to the present invention is 0% to 37% by weight, preferably 0% to 20% by weight, more preferably 0% to 10% by weight.

[0091] These other molding formulation components include, for example, other fillers conventional in polycarbonate molding formulations, other thermoplastics, for example, acrylonitrile-butadiene-styrene copolymer, styrene-acrylonitrile copolymer, or also polyester, or other additives, such as UV stabilizers, IR stabilizers, heat stabilizers, antistatic agents, dyes, and pigments, added in conventional amounts; Optionally, release properties, flow properties and / or flame retardancy may be further improved by adding external release agents, flow agents and / or flame retardants (e.g., alkyl and aryl phosphites, phosphates, and phosphans, low molecular weight carboxylic acid esters, halogen compounds, salts, chalk, quartz powder, glass fibers, carbon fibers, pigments, and combinations thereof). Such compounds are described, for example, in WO 99 / 55772, pp. 15-25, and in the literature ("Plastics Additives", R. Gaechter and H. Mueller, Hanser Publishers 1983). Carboxylic acid anhydride-modified alpha-olefin polymers, particularly maleic anhydride-modified alpha-olefin polymers, are preferred as stabilizers. Such carboxylic acid anhydride-modified alpha-olefin polymers are known, for example, from WO2018037037A1.

[0092] The polyester described above and the polyester carbonate further described above should be distinguished from one another. For the purposes of the present invention, the polyesters are those described in paragraphs

[0131] through

[0138] of US 2014 / 357769 A1.

[0093] The proportion of polyester in the molding formulation is 0.9 weight% or less, preferably 0.5 weight% or less, more preferably 0.2 weight% or less, particularly preferably 0.1 weight% or less, and very particularly preferably 0 weight% to 0.1 weight%. Most preferably, the proportion of polyester in the molding formulation is 0 weight%.

[0094] In one alternative according to the present invention, the proportion of polyester in the molding composition is 22 weight% or more to 58 weight% or less, preferably 23 weight% or more to 55 weight% or less, more preferably 25 weight% or more to 50 weight% or less.

[0095] Suitable additives are described, for example, in the literature ("Additives for Plastics Handbook, John Murphy, Elsevier, Oxford 1999") and the literature ("Plastics Additives Handbook, Hans Zweifel, Hanser, Munich 2001").

[0096] Examples of suitable antioxidants / heat stabilizers include alkylated monophenols, alkylthiomethylphenols, hydroquinones and alkylated hydroquinones, tocopherols, hydroxylated thiodiphenyl ethers, alkylidenebisphenols, O-, N- and S-benzyl compounds, hydroxybenzyl malonates, aromatic hydroxybenzyl compounds, triazine compounds, acylaminophenols, esters of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid, esters of β-(5-tert-butyl-4-hydroxy-3-methylphenyl)propionic acid, esters of β-(3,5-dicyclohexyl-4-hydroxyphenyl)propionic acid, and esters of 3,5-di-tert-butyl-4-hydroxyphenylacetic acid. It includes amide of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid, suitable thio-stimulators, secondary antioxidants, phosphites and phosphonites, benzofuranone, and indolinone.

[0097] Organic phosphites, phosphonates, and phosphans are preferred, and those that consist entirely or partially of aromatic radicals to which organic radicals are optionally substituted are preferred.

[0098] Complexing agents suitable for neutralizing heavy metals and trace amounts of alkali are ortho- and metaphosphoric acids, and completely or partially esterified phosphates or phosphites.

[0099] Suitable light stabilizers (UV absorbers) are 2-(2'-hydroxyphenyl)benzotriazole, 2-hydroxybenzophenone, esters of substituted and unsubstituted benzoic acids, acrylates, sterically hindered amines, oxamides, and also 2-(hydroxyphenyl)-1,3,5-triazine and substituted hydroxyalkoxyphenyl-1,3,5-triazole, and substituted benzotriazoles, e.g., 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-t-butylphenyl)benzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3',5'-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-tert-amylphenyl)benzotriazole, 2-[2'-hydroxy-3'-(3",4",5",6"-tetrahydrophthalimidoethyl)-5'-methylphenyl]benzotriazole, and 2,2'-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazole-2-yl)phenol] are preferred.

[0100] Polypropylene glycol can be used as a stabilizer to prevent damage caused by gamma rays, either alone or in combination with, for example, sulfone or sulfonamide.

[0101] These and other stabilizers may be used individually or in combination and may be added to polycarbonate in the mentioned forms.

[0102] It is also possible to add processing aids, such as release agents, which are primarily derivatives of long-chain fatty acids. For example, pentaerythritol tetrastearate and glycerol monostearate are preferred. The release agents are used either alone or as a mixture.

[0103] Suitable flame retardant additives are phosphate esters, namely triphenyl phosphate, resorcinol diphosphate, brominated compounds, such as brominated phosphate esters, brominated oligocarbonates and polycarbonates, and preferably salts of fluorinated organic sulfonic acids.

[0104] Suitable impact modifiers are butadiene rubber having grafted styrene-acrylonitrile or methyl methacrylate, ethylene-propylene rubber having grafted maleic anhydride, ethyl and butyl acrylate rubber having grafted methyl methacrylate or styrene-acrylonitrile, and interpenetrating siloxane and acrylate network structures having grafted methyl methacrylate or styrene-acrylonitrile.

[0105] In addition, coloring agents, such as organic dyes or pigments or inorganic pigments, and IR absorbers may be added individually, as a mixture, or in combination with stabilizers, glass fibers, (hollow) glass beads, and inorganic fillers, particularly mineral fillers, wherein these mineral fillers may also be reinforcing fillers, particularly titanium dioxide (TiO2) and talc (Mg3Si4O2). 10 (OH)2), Dolomite CaMg[CO3]2, Kaolinite Al4[(OH)8|Si4O 10 ], and wollastonite Ca3[Si3O9], very particularly titanium dioxide (TiO2) and talc (Mg3Si4O 10 Includes (OH)2).

[0106] The polycarbonate molding formulation according to the present invention may be used in any case where a known polycarbonate molding formulation is used, optionally as a mixture with other thermoplastic plastics and / or conventional additives.

[0107] A continuous single-shaft mixer has a single rotating screw shaft that rotates and simultaneously performs axial reciprocating motion, causing vibratory motion, particularly sinusoidal vibratory reciprocating motion. The maximum length of the axial path traversed by the screw shaft during forward or backward motion is also referred to as the stroke, and the length of the path traversed by the screw shaft during forward motion is equal to the length of the path traversed by the screw shaft during backward motion.

[0108] In the screw shaft of a continuous single-shaft kneader, a screw set having a screw profile similar to that of a screw in a single-shaft extruder typically used for the extrusion of plastic molding formulations is positioned, but the difference is that the screw elements in the main components of the continuous single-shaft kneader are interrupted and subdivided to form so-called kneading blades. The screw set of the continuous single-shaft kneader consists of screw elements that can be arranged modularly on the screw shaft. The screw elements can have various lengths and can also have kneading blade profiles with various geometries and pitches. Both 3- and 4-blade screw elements can be used.

[0109] A kneading pin fixed in place is located in the housing surrounding the screw shaft. Typically, 3-row (3-blade) or 4-row (4-blade) kneading pins are present along the housing of a continuous single-shaft kneader. The kneading pins can have a cross-section that is, for example, circular or diamond-shaped and can have various lengths and cross-sectional areas.

[0110] The housing and screw shaft of a continuous single-shaft mixer can be designed to enable both heating and cooling.

[0111] The outer diameter of the screw element is also referred to as DE. The core radius of the screw element is referred to as DI.

[0112] For the purposes of the present invention, the L / D ratio is the ratio of the length of the section of the screw shaft equipped with the screw element to the outer diameter of the screw element.

[0113] When discharging a molten material from a continuous single-shaft kneader, for example through a die plate, it is customary to use a separate discharge element because the continuous single-shaft kneader itself cannot generate sufficient pressure to allow passage through the die plate. The discharge element may be, for example, a single-shaft extruder, a twin-shaft extruder, or a melt pump. Such a discharge element is located downstream of the continuous single-shaft kneader, preferably immediately downstream of the continuous single-shaft kneader, but may also be separated from it by a chute or flange.

[0114] The continuous single-shaft kneader itself is known from, for example, DE1908414A1, DD71190A, and the literature ("Einfuehrung in die Kunststoffverarbeitung" [Introduction to plastics processing], Carl Hanser Verlag, Munich, 8th edition, 2017, pages 104-105), the publication ("Der Ko-Kneter in der Plastik-Industrie" [The co-kneader in the plastics industry] in the journal Schweizer Maschinenmarkt, 1960, pages 54-61), and the literature ("Mixing in polymer processing", Marcel Dekker Inc., 1991, pages 200-219).

[0115] In addition, it is known that a continuous single-shaft mixer exhibits excellent distribution mixing effects, for example, from the literature ("Introduction to plastics processing", Carl Hanser Verlag, Munich, 8th edition, 2017, pages 104-105) and the literature ("Mixing in polymer processing", Marcel Dekker Inc., 1991, pages 200-219).

[0116] However, the prior art does not disclose that an improved dispersion mixture, namely a mixture in which particles are not only distributed by volume but are also further ground, can be achieved using a continuous single-shaft kneader. Nowhere in the prior art is it disclosed that a polycarbonate masterbatch containing reinforcing fillers and capable of producing a polycarbonate molding compound having improved properties can be produced using a continuous single-shaft kneader. In particular, a method for producing a polycarbonate molding compound containing a reinforcing filler is not disclosed anywhere in the prior art, wherein the total content of the reinforcing filler is 3% to 20% by weight, preferably 4.5% to 15% by weight, based on the total mass of the polycarbonate molding compound in each case, and the polycarbonate molding compound is produced using a polycarbonate masterbatch produced using a continuous single-shaft kneader, and such polycarbonate masterbatch has a total reinforcing filler content of 30% to 70% by weight, preferably 35% to 65% by weight, more preferably 40% to 60% by weight, based on the total mass of the masterbatch in each case. The reinforcing filler is preferably titanium dioxide (TiO2) or talc (Mg3Si4O2) in each case. 10(OH)2), Dolomite CaMg[CO3]2, Kaolinite Al4[(OH)8|Si4O 10 Selected from the group comprising ] and wollastonite Ca3[Si3O9], preferably titanium dioxide (TiO2) and talc (Mg3Si4O2 10 It is selected from the group including (OH)2).

[0117] This type of polycarbonate molding compound prepared according to the present invention has superior properties compared to a polycarbonate molding compound prepared by a method according to the prior art, which contains the same components as the polycarbonate molding compound prepared according to the present invention in the same proportion.

[0118] According to the present invention, it is preferable to manufacture a polycarbonate masterbatch using a continuous single-shaft kneader having a DE / stroke ratio of 4 to 7, more preferably 5.5 to 6.7.

[0119] According to the present invention, it is further preferable that the continuous single-shaft kneader has an L / D ratio of 10 to 25.

[0120] According to the present invention, it is further preferable that a continuous single-shaft kneader has a DE / DI ratio of 1.5 to 1.8, more preferably 1.55 to 1.71.

[0121] According to the present invention, it is further preferable that the screw element of a continuous single-shaft kneader has an outer diameter DE of 30 to 200 mm.

[0122] According to the present invention, it is further preferable that the continuous single-shaft kneader has a flight depth defined as (DE - DI) / 2 of 5 to 92 mm.

[0123] The continuous single-shaft kneader used according to the present invention may be, for example, a Buss ball-kneader manufactured by Buss AG (Switzerland) under the name Mx or MKS or MDK, a single-shaft kneader manufactured by Xinda (China) under the name SJW, or a single-shaft kneader manufactured by X-Compound (Switzerland) under the name CK.

[0124] The present invention further provides a masterbatch prepared by the method according to the present invention.

[0125] The present invention further provides a molding formulation prepared by the method according to the present invention.

[0126] The molding formulation according to the present invention is also characterized by being usable in injection molding without additional processing after cooling.

[0127] The present invention also provides a use of the molding compound according to the present invention for the manufacture of molded articles, particularly articles obtainable by injection molding or films, sheets, or profiles obtainable by extrusion of the molding compound, or light reflectors or structural parts, for example, structural parts for the manufacture of automobiles. The excellent surface properties of the molding compound allow the molded articles produced therefrom to undergo electroplating or metal deposition easily.

[0128] The present invention is described below with reference to examples, but there is no intention to limit the invention to these examples.

[0129] Comparative Examples

[0130] The experiment described in Comparative Example 1 was performed using a ZSK92 Mc+ twin-screw extruder from Coperion GmbH. The twin-screw extruder used had a housing bore of 93 mm and an L / D ratio of 36. The basic structure of the extruder used is illustrated in Fig. 1c. The twin-screw extruder has a housing consisting of nine parts in which two co-rotating meshing shafts (not shown) are arranged.

[0131] In Example 1, metering of all components of the polycarbonate molding mixture was performed through the main inlet in the housing (49) via the illustrated supply hopper (48).

[0132] In the area of ​​the housing (49 to 52), a transfer zone for polycarbonate pellet material, titanium dioxide powder, and other molding compound components is located.

[0133] In the area of ​​the housing (52 to 54), there is a plasticizing zone consisting of various 2- and 3-flight mixing blocks of various widths and also sawtooth mixing elements.

[0134] A mixing zone consisting of a mixing element, a toothed mixing element, and a conveying element is located in the area of ​​the housing (54 to 55).

[0135] In the housing part (56), a side vent (58) connected to a twin-shaft side-vent extruder (not shown) and an extraction device (not shown) connected thereto is located.

[0136] A pressurized band is located in the housing (57), and downstream therefrom is a melt filtration device in the form of a K-SWE-250 double-piston screen changer from Kreyenborg GmbH. In each of the two screen cavities of the double-piston screen changer, there is a breaker plate and a 4-layer melt filtration pack consisting of a linen-woven square mesh fabric with mesh sizes of 315 / 200 / 315 / 800 μm. Downstream of the screen changer, there is a starter valve (not shown) from Trendelkamp GmbH and an EAC-7 underwater pelletizer (not shown) from Gala with a die plate having 100 holes.

[0137] In Example 1, a powder mixture comprising polycarbonate pellet material and titanium dioxide powder was weighed and added to a feed hopper (48) using a commercially available differential weight feeder.

[0138] In Example 1, pelletization was performed in the form of underwater pelletization.

[0139] In Example 1, the melting temperature was measured using a thermocouple fixed to the housing of the starting valve by a screw.

[0140] The experiments described in Comparative Examples 3 and 5 were performed using a ZE60A UTXi twin-screw extruder from KraussMaffei Berstorff GmbH. The twin-screw extruder used has a housing bore of 65 mm and an L / D ratio of 43. The basic structure of the extruder used is illustrated in FIG. 1. The twin-screw extruder has a housing consisting of 11 parts in which two co-rotating meshing shafts (not shown) are arranged.

[0141] In Examples 3 and 5, metering of all components of the polycarbonate molding mixture was performed through the main inlet in the housing (2) via the illustrated supply hopper (1).

[0142] In the area of ​​the housing (2 to 7), a transfer zone for polycarbonate pellet material, titanium dioxide powder, and other molding compound components is located.

[0143] In the area of ​​the housing (8), there is a plasticizing zone consisting of various 2- and 3-flight mixing blocks of various widths and also sawtooth blocks.

[0144] A mixing zone consisting of a mixing element, a toothed block, and a conveying element is located in the area of ​​the housing (9 to 10).

[0145] A ventilation port (13) connected to an extraction device (not shown) is located in the housing part (11).

[0146] A pressurized band is located in the housing (12), and a die plate having 29 holes is located downstream of it.

[0147] In Examples 3 and 5, a powder mixture comprising polycarbonate pellet material and titanium dioxide powder was weighed and added to a feed hopper (1) using a commercially available differential weight feeder. Additionally, additional titanium dioxide powder was weighed and added to the feed hopper (1) using a separate commercially available differential weight feeder.

[0148] In Examples 3 and 5, pelletization was performed in the form of strand pelletization after cooling in a water bath.

[0149] In Examples 3 and 5, the melting temperature was measured by inserting a thermocouple into the discharge melt of the central melt strand immediately upstream of the die plate.

[0150] Examples according to the present invention

[0151] In Examples 2.1 and 2.1.1 according to the present invention, a polycarbonate masterbatch containing titanium dioxide was first prepared using a Ko-Kneter Mx 58 continuous single-shaft kneader from Bus AG. Subsequently, from this polycarbonate masterbatch, polycarbonate, and other molding compound components, a polycarbonate molding compound having improved properties was prepared using a ZSK92 Mc+ twin-screw extruder from Coperion GmbH.

[0152] The ball-kneader used for the production of the polycarbonate masterbatch according to the present invention in Example 2.1 has a housing inner diameter of 58.4 mm, a screw element outer diameter DE of 57.7 mm in the bearing area, a screw element outer diameter DE of 56.3 mm in the area outside the bearing, an L / D ratio of 15, a DE / DI ratio of 1.55 from the starting point of the ball-kneader shaft to the restrictor ring at the end of the melting zone, a DE / DI ratio of 1.71 from the restrictor ring to the end of the ball-kneader shaft, and a DE / stroke ratio of 5.5. The total length of the bearing area is approximately 15% of the total length of the screw shaft of the continuous single-shaft kneader. The area from the starting point of the ball-kneader shaft to the restrictor ring amounts to 40% of the total length of the ball-kneader shaft.

[0153] The basic structure of the continuous single-shaft mixer used is illustrated in FIG. 2. The continuous single-shaft mixer has a housing made of three parts in which a screw shaft (not shown) that rotates and reciprocates axially is arranged.

[0154] The melt is discharged from the continuous single-shaft kneader by a single-screw extruder (not shown in Fig. 2) having a housing inner diameter of 110 mm and an L / D ratio of 6. The single-screw extruder is mounted directly onto the continuous single-shaft kneader via a flange, and its sole purpose is to perform pressurization during the pelletization of the polycarbonate molding compound. Significant mixing and / or grinding of the molding compound components is not performed in the single-screw extruder. At the end of the single-screw extruder, a die plate having a diameter of 118.5 mm is located for the formation of molten strands. The die plate has 66 holes, each with a diameter of 3 mm, for the discharge of the melt. The molten strands discharged from the die plate are pelletized by hot-cut pelletization, that is, the molten strands are cut by a rotary knife in a water stream.

[0155] In Example 2.1 according to the present invention for the manufacture of a polycarbonate masterbatch, titanium dioxide powder was metered and added to the housing (31) through the illustrated feed hopper (29). Polycarbonate and other masterbatch components were fed through the feed hopper (28) to a continuous single-shaft mixer in the housing (30).

[0156] In the area of ​​the housing (30), a transfer zone consisting of a transfer element for polycarbonate pellet material and other masterbatch components is located.

[0157] A plasticizing zone consisting of various mixing and kneading elements is located in the area of ​​the housing (31). At the end of the plasticizing zone immediately upstream of the vent (33), a limiter ring having an inner diameter of 43 mm is located. Additionally, at the end of the housing (31), a conveying zone for titanium dioxide powder consisting of conveying elements is located.

[0158] In the area of ​​the housing (32), there is a transfer zone consisting of a transfer element and two mixing zones consisting of various mixing and kneading elements; one of which is located at the beginning of the housing and the other at the end of the housing. Additionally, between the mixing zones within the housing (32), there is a devolatilization zone consisting of a transfer element.

[0159] A ventilation port (34) connected to an extraction device (not shown) is located in the housing part (32).

[0160] In Example 2.1.1, the preparation of a polycarbonate molding compound according to the present invention was carried out using a ZSK92 Mc+ twin-screw extruder from Coperion GmbH. The twin-screw extruder used has a housing inner diameter of 93 mm and an L / D ratio of 36. The twin-screw extruder has a housing consisting of nine parts in which two co-rotating meshing shafts (not shown) are arranged. The basic structure of the extruder used is shown in FIG. 1c.

[0161] In Example 2.1.1, metering of all components of the polycarbonate molding mixture was performed through the main inlet in the housing (49) via the illustrated supply hopper (48).

[0162] In the area of ​​the housing (49 to 52), a transfer zone for polycarbonate pellet material, polycarbonate masterbatch, and other molding compound components is located.

[0163] In the area of ​​the housing (52 to 54), there is a plasticizing zone consisting of various 2- and 3-flight mixing blocks of various widths and also sawtooth mixing elements.

[0164] A mixing zone consisting of a mixing element, a toothed mixing element, and a conveying element is located in the area of ​​the housing (54 to 55).

[0165] In the housing part (56), a side vent (58) connected to a twin-shaft side-vent extruder (not shown) and an extraction device (not shown) connected thereto is located.

[0166] A pressurized band is located in the housing (57), and downstream therefrom is a melt filtration device in the form of a K-SWE-250 double-piston screen changer from Krejenborg GmbH. In each of the two screen cavities of the double-piston screen changer, there is a 4-layer melt filtration pack consisting of a breaker plate and a linen-woven square mesh fabric with mesh sizes of 315 / 200 / 315 / 800 μm. Downstream of the screen changer, there is a starter valve (not shown) from Trendelkamp GmbH and an EAC-7 underwater pelletizer (not shown) from Gala with a die plate having 100 holes.

[0167] In Example 2.1.1 according to the present invention, the polycarbonate pellet material, the powder mixture, and the polycarbonate masterbatch prepared in Example 2.1 according to the present invention were weighed and added to a feed hopper (48) using a commercially available differential weight feeder.

[0168] In Example 2.1.1, pelletization was performed in the form of underwater pelletization.

[0169] In Example 2.1.1, the melting temperature was measured using a thermocouple fixed to the housing of the starting valve by a screw.

[0170] In Examples 4.1, 4.1.1 and 6.1 according to the present invention, a polycarbonate masterbatch containing titanium dioxide was first prepared using a Cochnetter Mx 58 continuous single-shaft kneader from Buss AG. Then, from this polycarbonate masterbatch, polycarbonate, and other molding compound components, a polycarbonate molding compound with improved properties was prepared using a ZE60A UTXi twin-screw extruder from Krauss-Maffei-Werstof GmbH.

[0171] The ball-kneader used for the manufacture of polycarbonate masterbatch has a housing inner diameter of 58.4 mm, a screw element outer diameter DE of 57.7 mm in the bearing area, a screw element outer diameter DE of 56.3 mm in the non-bearing area, an L / D ratio of 15, a DE / DI ratio of 1.55 from the starting point of the ball-kneader shaft to the limiter ring at the end of the melting zone, a DE / DI ratio of 1.71 from the limiter ring to the end of the ball-kneader shaft, and a DE / stroke ratio of 5.5. The total length of the bearing area is approximately 15% of the total length of the screw shaft of the continuous single-shaft kneader. The area from the starting point of the ball-kneader shaft to the limiter ring amounts to 40% of the total length of the ball-kneader shaft.

[0172] The basic structure of the continuous single-shaft mixer used is illustrated in FIG. 2. The continuous single-shaft mixer has a housing made of three parts in which a screw shaft (not shown) that rotates and reciprocates axially is arranged.

[0173] The melt is discharged from the continuous single-shaft kneader by a single-screw extruder (not shown in Fig. 2) having a housing inner diameter of 110 mm and an L / D ratio of 6. The single-screw extruder is mounted directly onto the continuous single-shaft kneader via a flange, and its sole purpose is to perform pressurization during the pelletization of the polycarbonate molding compound. Significant mixing and / or grinding of the molding compound components is not performed in the single-screw extruder. At the end of the single-screw extruder, a die plate having a diameter of 118.5 mm is located for the formation of molten strands. The die plate has 66 holes, each with a diameter of 3 mm, for the discharge of the melt. The molten strands discharged from the die plate are pelletized by hot-cut pelletization, that is, the molten strands are cut by a rotary knife in a water stream.

[0174] In Examples 4.1 and 6 according to the present invention for the manufacture of a polycarbonate masterbatch according to the present invention, titanium dioxide powder was metered and added to the housing (31) through the illustrated supply hopper (29). Polycarbonate and other masterbatch components were supplied to a continuous single-shaft mixer in the housing (30) through the supply hopper (28).

[0175] In the area of ​​the housing (30), a transfer zone consisting of a transfer element for polycarbonate pellet material and other masterbatch components is located.

[0176] A plasticizing zone consisting of various mixing and kneading elements is located in the area of ​​the housing (31). At the end of the plasticizing zone immediately upstream of the vent (33), a limiter ring having an inner diameter of 43 mm is located. Additionally, at the end of the housing (31), a conveying zone for titanium dioxide powder consisting of conveying elements is located.

[0177] In the area of ​​the housing (32), there is a transfer zone consisting of a transfer element and two mixing zones consisting of various mixing and kneading elements; one of which is located at the beginning of the housing and the other at the end of the housing. Additionally, between the mixing zones within the housing (32), there is a devolatilization zone consisting of a transfer element.

[0178] A ventilation port (34) connected to an extraction device (not shown) is located in the housing part (32).

[0179] In Examples 4.1.1 and 6.1, the preparation of polycarbonate molding formulations according to the present invention was carried out using a ZE60A UTXi twin-screw extruder from Krauss-Maffei Versthorf GmbH. The twin-screw extruder has a housing inner diameter of 65 mm and an L / D ratio of 43. The basic structure of the extruder used in Examples 4.1.1 and 6.1 is shown in FIG. 1.

[0180] In Examples 4.1.1 and 6.1, metering of all components of the polycarbonate molding mixture was performed through the main inlet in the housing (2) via the illustrated supply hopper (1).

[0181] In the area of ​​the housing (2 to 7), a transfer zone for polycarbonate pellet material, polycarbonate masterbatch, and other molding compound components is located.

[0182] In the area of ​​the housing (8), there is a plasticizing zone consisting of various 2- and 3-flight mixing blocks of various widths and also sawtooth blocks.

[0183] A mixing zone consisting of a mixing element, a toothed block, and a conveying element is located in the area of ​​the housing (9 to 10).

[0184] A ventilation port (13) connected to an extraction device (not shown) is located in the housing part (11).

[0185] A pressurized band is located in the housing (12), and a die plate having 29 holes is located downstream of it.

[0186] In Example 4.1.1, the polycarbonate pellet material, the polycarbonate masterbatch obtained from Example 4.1 according to the present invention in the case of Example 4.1.1, and other molding compound components were metered and added to the feed hopper (1) using a commercially available differential weight feeder.

[0187] In Example 6.1, polycarbonate pellet material, the polycarbonate masterbatch obtained from Example 6.1 according to the present invention, and other molding formulation components were metered and added to a feed hopper (1) using a commercially available differential weight feeder.

[0188] In Examples 4.1.1 and 6.1, pelletization was performed in the form of strand pelletization after cooling in a water bath.

[0189] In Examples 4.1.1 and 6.1, the melting temperature was measured by inserting a thermocouple into the discharge melt of the central melt strand immediately upstream of the die plate.

[0190] In the area of ​​the housing (15 to 18), a transfer zone for polycarbonate pellet material, polycarbonate masterbatch, and other solid molding compound components is located.

[0191] In the area of ​​the housing (19), there is a plasticizing zone consisting of various 2- and 3-flight mixing blocks of various widths and also sawtooth blocks.

[0192] A mixing zone consisting of a mixing element, a toothed block, and a conveying element is located in the area of ​​the housing (21 to 23).

[0193] A ventilation port (26) connected to an extraction device (not shown) is located in the housing part (24).

[0194] A pressurized band is located in the housing (25), and a die plate having 29 holes is located downstream of it.

[0195] The ball-kneader used for the manufacture of polycarbonate masterbatch has a housing inner diameter of 58.4 mm, a screw element outer diameter DE of 57.7 mm in the bearing area, a screw element outer diameter DE of 56.3 mm in the non-bearing area, an L / D ratio of 15, a DE / DI ratio of 1.55 from the starting point of the ball-kneader shaft to the limiter ring at the end of the melting zone, a DE / DI ratio of 1.71 from the limiter ring to the end of the ball-kneader shaft, and a DE / stroke ratio of 5.5. The total length of the bearing area is approximately 15% of the total length of the screw shaft of the continuous single-shaft kneader. The area from the starting point of the ball-kneader shaft to the limiter ring amounts to 40% of the total length of the ball-kneader shaft.

[0196] The basic structure of the continuous single-shaft mixer used is illustrated in FIG. 2. The continuous single-shaft mixer has a housing made of three parts in which a screw shaft (not shown) that rotates and reciprocates axially is arranged.

[0197] The melt is discharged from the continuous single-shaft kneader by a single-screw extruder (not shown in Fig. 2) having a housing inner diameter of 110 mm and an L / D ratio of 6. The single-screw extruder is mounted directly onto the continuous single-shaft kneader via a flange, and its sole purpose is to perform pressurization during the pelletization of the polycarbonate masterbatch. Significant mixing and / or grinding of all masterbatch components is not performed in the single-screw extruder. At the end of the single-screw extruder, a die plate having a diameter of 118.5 mm is located for the formation of molten strands. The die plate has 66 holes, each with a diameter of 3 mm, for the discharge of the melt. The molten strands discharged from the die plate are pelletized by hot-cut pelletization, that is, the molten strands are cut by a rotary knife in a water stream.

[0198] Next, the polycarbonate molding formulations prepared in Examples 1, 2.1.1, 3, 4.1.1, 5, and 6.1 were processed through an injection molding process on an FM160 injection molding machine from Kloeckner to produce a sheet having a glossy surface and dimensions of 150 mm x 105 mm x 3.2 mm (length x width x thickness).

[0199] The injection molding machine has a cylinder diameter of 45 mm. Sheets were manufactured using a polished injection mold (ISO N1). The polycarbonate molding formulation was pre-dried at 110°C for 4 hours prior to injection molding. Processing by injection molding was performed under conditions characteristic of polycarbonate. During the manufacture of sheets in Examples 1, 2.1.1, 5, and 6.1, the melt temperature was 280°C, the mold temperature was 80°C, the cycle time was 43 seconds, and the injection speed was 40 mm / sec. During the manufacture of sheets in Examples 3 and 4.1.1, the melt temperature was 300°C, the mold temperature was 90°C, the cycle time was 43 seconds, and the injection speed was 40 mm / sec.

[0200] The surface of the sheet, using a Zeiss Axioplan 2 optical microscope, at 16 cm in brightfield contrast of incident light 2Sections are recorded with the assistance of a scanning table. The light source used is a Halogen 100 light source present within the microscope as a reflected light source. The magnification was selected to enable the detection of structures on the sheet surface having a diameter greater than 10 μm. To achieve this, an Epiplan-Neofluar 2.5 / 0.075 HD lens with an effective resolution of 3.94 μm / pixel is used. A surface area measuring 4 cm x 4 cm is inspected by meandering scanning, and photographs of this surface are obtained using an Axiocam HRC CCD camera. Surface defects are detected through automatic image evaluation of the photographs using the microscope's proprietary Zeiss KS 300 software. The number and diameter of surface defects in the equivalent circle diameter (ECD) are determined. The number of surface defects is determined using all surface defects having a size of at least 10 μm. To record the defect size distribution, the recorded defect diameters are classified into classes with a width of 10 micrometers. For each test, measurements are performed and evaluated on three sheets. In each case, the measurement results for the three sheets are cm relative to the inspected sheet surface. 2 The number of surface defects recorded per sheet, their minimum and maximum diameters, the arithmetic mean of the defect diameters for three sheets, the median of the defect diameters for three sheets, and the standard deviation of the defect diameters for three sheets. The entire method is commercially available from Currenta GmbH und Co. OHG of Germany under the designation SOP00014 "Plattenscan". In Table 1, cm 2 The values ​​indicated for the number of defects, average defect diameter, and maximum defect diameter are the arithmetic mean of the number of defects of at least 10 μm obtained by measurements on three injection-molded sheets in each case.

[0201] The specific surface quality of the injection-molded article produced from the molding formulation is cm in each case 2 It is calculated by multiplying the arithmetic mean of the number of defects in three injection-molded sheets by the average defect diameter in μm and dividing the result by the reinforcing filler content of the molding formulation in weight percent, wherein 1 weight percent is calculated as 0.01 and 100 weight percent is calculated as 1.00. The specific surface quality of each molding formulation is recorded in Table 1. The higher the specific surface quality value, the worse the surface quality of the molding formulation. All embodiments according to the present invention are 550 m -1 All molding formulation examples manufactured according to the prior art, having a specific surface quality of less than 550 m -1 It has excess surface quality.

[0202] Surface defects on a molded article prepared from a polymer mixture having the aforementioned composition, which are optically detected in this manner, are caused by aggregates or clusters of titanium dioxide particles that are insufficiently decomposed during the melt mixing of the components in the extruder (refer to Fig. 3 containing a relatively large proportion of titanium dioxide (EDX spectrum for measurement point 04-01A)). The following additional particles capable of causing surface defects may be found in the mixture: decomposed PC (refer to Fig. 4; identifiable by the fluorescence of the particles), metal-containing particles (refer to Fig. 5 (EDX spectrum for measurement point 3-01B); identifiable by the contained iron). Metal-containing particles may occur, for example, when polycarbonate adhering to the inner housing of the extruder falls off and, along with it, metal particles in the housing of the extruder are torn off.

[0203] Although the inventors do not intend to be bound by any particular scientific theory, it can be reasonably inferred that the decomposed polycarbonate particles and metal-containing particles are caused by an increase in energy input into the polycarbonate molding mixture from a twin-screw extruder, which is necessary to achieve a dispersion close to that of the polycarbonate molding mixture by a continuous single-shaft kneader.

[0204] The molding mixture supplied to the extruder in Example 1 is

[0205] - 93 wt%, relative viscosity η rel Pellet of a linear polycarbonate based on bisphenol A having = 1.255 (measured in CH2Cl2 as a solvent at 25°C and a concentration of 0.5 g / 100 ml) and

[0206] - 0.1 wt% maleic anhydride-grafting polyolefin copolymer (AC 907P from Honeywell) and

[0207] - 3 wt% titanium dioxide powder (Kronos 2230 from Kronos Titanium), 3.1882 wt%, relative viscosity η rel Polycarbonate powder of a bisphenol A-based linear polycarbonate having = 1.255 (measured in CH2Cl2 as a solvent at 25°C and a concentration of 0.5 g / 100 ml) and a 6.99 wt% powder mixture comprising 0.0018 wt% additional colorant, 0.4 wt% stabilizer, and 0.4 wt% release agent.

[0208] It consists of a mixture of

[0209] The masterbatch composition supplied to the co-kneader in Examples 2.1, 4.1, and 6 is

[0210] - 58.7 wt%, relative viscosity η relPellet of a linear polycarbonate based on bisphenol A having = 1.293 (measured in CH2Cl2 as a solvent at 25°C and a concentration of 0.5 g / 100 ml) and

[0211] - 40 wt% titanium dioxide powder (Chronos 2230 from Chronos Titanium) and

[0212] - 1.3 wt% maleic anhydride-grafting polyolefin copolymer (AC 907P from Honeywell)

[0213] It consists of a mixture of

[0214] The molding mixture supplied to the extruder in Example 2.1.1 is

[0215] - 88.4 wt%, relative viscosity η rel Pellet of a linear polycarbonate based on bisphenol A having = 1.255 (measured in CH2Cl2 as a solvent at 25°C and a concentration of 0.5 g / 100 ml) and

[0216] - 7.6 wt% of the polycarbonate masterbatch prepared in Example 2.1 and

[0217] - 3.29 wt%, relative viscosity η rel Polycarbonate powder of a bisphenol A-based linear polycarbonate having = 1.255 (measured in CH2Cl2 as a solvent at 25°C and a concentration of 0.5 g / 100 ml) and a 4 wt% powder mixture comprising 0.31 wt% stabilizer and 0.4 wt% release agent

[0218] It consists of a mixture of

[0219] The molding mixture supplied to the extruder in Example 3 is

[0220] - 81 wt%, relative viscosity η relPellet of a linear polycarbonate based on bisphenol A having = 1.318 (measured in CH2Cl2 as a solvent at 25°C and a concentration of 0.5 g / 100 ml) and

[0221] - 14 wt% titanium dioxide powder (Chronos 2230 from Chronos Titanium) and

[0222] - 3.51 wt%, relative viscosity η rel Polycarbonate powder of a bisphenol A-based linear polycarbonate having = 1.318 (measured in CH2Cl2 as a solvent at a concentration of 0.5 g / 100 ml at 25°C), and a 5 wt% powder mixture comprising 1 wt% titanium dioxide powder (Kronos 2230 from Kronos Titanium) and 0.49 wt% maleic anhydride-grafted polyolefin copolymer (AC 907P from Honeywell).

[0223] It consists of a mixture of

[0224] The molding mixture supplied to the extruder in Example 4.1.1 is

[0225] - 62.2 wt%, relative viscosity η rel Pellet of a linear polycarbonate based on bisphenol A having = 1.318 (measured in CH2Cl2 as a solvent at 25°C and a concentration of 0.5 g / 100 ml) and

[0226] - 37.8 wt% of the polycarbonate masterbatch prepared in Example 4.1

[0227] It consists of a mixture of

[0228] The molding mixture supplied to the extruder in Example 5 is

[0229] - 89 wt%, relative viscosity η rel Pellet of a linear polycarbonate based on bisphenol A having = 1.255 (measured in CH2Cl2 as a solvent at 25°C and a concentration of 0.5 g / 100 ml) and

[0230] - 6 wt% titanium dioxide powder (Chronos 2230 from Chronos Titanium) and

[0231] - 3.265 wt%, relative viscosity η rel Polycarbonate powder of a bisphenol A-based linear polycarbonate having = 1.255 (measured in CH2Cl2 as a solvent at 25°C and a concentration of 0.5 g / 100 ml) and also a 5.02 wt% powder mixture comprising 0.75 wt% titanium dioxide powder (Cronos 2230 from Cronos Titanium), 0.22 wt% maleic anhydride-grafted polyolefin copolymer (AC 907P from Honeywell), 0.02 wt% additional colorant, 0.365 wt% stabilizer, and 0.4 wt% release agent.

[0232] It consists of a mixture of

[0233] The molding mixture supplied to the extruder in Example 6.1 is

[0234] - 78.9 wt%, relative viscosity η rel Pellet of a linear polycarbonate based on bisphenol A having = 1.255 (measured in CH2Cl2 as a solvent at 25°C and a concentration of 0.5 g / 100 ml) and

[0235] - 17.1 wt% polycarbonate masterbatch prepared in Example 6 and

[0236] - 3.235 wt%, relative viscosity η rel Polycarbonate powder of a bisphenol A-based linear polycarbonate having = 1.255 (measured in CH2Cl2 as a solvent at 25°C and a concentration of 0.5 g / 100 ml) and a 4.02 wt% powder mixture comprising 0.02 wt% additional coloring agent, 0.365 wt% stabilizer, and 0.4 wt% release agent.

[0237] It consists of a mixture of

[0238] Comparative Example 1

[0239] In Comparative Example 1, a molding compound composition containing 3 wt% titanium dioxide is compounded using a throughput of 2100 kg / h, a screw-shaft speed of 600 l / min, and a resulting non-mechanical energy input of 0.174 kWh / kg. The temperature of the molten material discharged from the die plate is 354°C.

[0240] The surface of the three injection-molded sheets from the formulated molding mixture is cm 2 It has an average of 88 defects, an average defect diameter of 20.1 μm, and a maximum defect diameter of 104.8 μm. The specific surface quality is 590 m -1 am.

[0241] Example 2.1 (According to the present invention - Polycarbonate masterbatch)

[0242] In Example 2.1 according to the present invention, a polycarbonate masterbatch composition containing 40 wt% titanium dioxide is blended using a throughput of 120 kg / h, a speed of 200 l / min, and a resulting non-mechanical energy input of 0.067 kWh / kg. The temperature of the melt discharged from the die plate is 275°C.

[0243] Example 2.1.1 (According to the present invention - Polycarbonate molding compound)

[0244] In Example 2.1.1 according to the present invention, a molding compound composition comprising 3 wt% titanium dioxide introduced by the polycarbonate masterbatch prepared according to Example 2.1 is compounded using a throughput of 3000 kg / h, a screw-shaft speed of 500 l / min, and a resulting non-mechanical energy input of 0.142 kWh / kg. The temperature of the melt discharged from the extruder is 327°C.

[0245] The surface of the three injection-molded sheets from the formulated molding mixture is cm 2It has an average of 79 defects, an average defect diameter of 20.1 μm, and a maximum defect diameter of 66.5 μm.

[0246] The specific surface quality is 529 m -1 am.

[0247] Accordingly, by using the polycarbonate masterbatch according to the present invention, it was possible to produce a molding formulation having improved specific surface quality with a throughput 43% higher and a melting temperature 27°C lower than Comparative Example 1.

[0248] Comparative Example 3

[0249] In Comparative Example 3, a molding compound composition containing 15 wt% titanium dioxide is compounded using a throughput of 690 kg / h, a screw-shaft speed of 260 l / min, and a resulting non-mechanical energy input of 0.131 kWh / kg. The temperature of the molten material discharged from the die plate is 326°C.

[0250] The surface of the three injection-molded sheets from the formulated molding mixture is cm 2 It has an average of 2,948 defects, an average defect diameter of 40.8 μm, and a maximum defect diameter of 206.2 μm. The specific surface quality is 8,019 m -1 am.

[0251] Example 4.1 (According to the present invention - Polycarbonate masterbatch)

[0252] In Example 4.1 according to the present invention, a polycarbonate masterbatch composition containing 40 wt% titanium dioxide is blended using a throughput of 120 kg / h, a speed of 200 l / min, and a resulting non-mechanical energy input of 0.067 kWh / kg. The temperature of the melt discharged from the die plate is 275°C.

[0253] Example 4.1.1 (According to the present invention - Polycarbonate molding compound)

[0254] In Example 4.1.1 according to the present invention, a molding compound composition comprising 15 wt% titanium dioxide introduced by the polycarbonate masterbatch prepared according to Example 4.1 is compounded using a throughput of 690 kg / h, a screw-shaft speed of 260 l / min, and a resulting non-mechanical energy input of 0.139 kWh / kg. The temperature of the molten material discharged from the extruder is 329°C.

[0255] The surface of the three injection-molded sheets from the formulated molding mixture is cm 2 It has an average of 78 defects, an average defect diameter of 16.2 μm, and a maximum defect diameter of 125 μm.

[0256] The specific surface quality is 84 m -1 am.

[0257] Therefore, by using the polycarbonate masterbatch according to the present invention, it was possible to produce a molding formulation having improved specific surface quality without any change in throughput and without any increase in energy input compared to Comparative Example 3.

[0258] Comparative Example 5

[0259] In Comparative Example 5, a molding compound composition containing 6.75 wt% titanium dioxide is compounded using a throughput of 720 kg / h, a screw-shaft speed of 270 l / min, and a resulting non-mechanical energy input of 0.132 kWh / kg. The temperature of the molten material discharged from the die plate is 297°C.

[0260] The surface of the three injection-molded sheets from the formulated molding mixture is cm 2 It has an average of 128 defects, an average defect diameter of 32.3 μm, and a maximum defect diameter of 176.3 μm.

[0261] The specific surface quality is 613 m -1 am.

[0262] Example 6 (According to the present invention - polycarbonate masterbatch)

[0263] In Example 6 according to the present invention, a polycarbonate masterbatch composition containing 40 wt% titanium dioxide is blended using a throughput of 120 kg / h, a speed of 200 l / min, and a resulting non-mechanical energy input of 0.067 kWh / kg. The temperature of the melt discharged from the die plate is 275°C.

[0264] Example 6.1 (According to the present invention - Polycarbonate molding compound)

[0265] In Example 6.1 according to the present invention, a molding compound composition comprising 6.75 wt% titanium dioxide introduced by the polycarbonate masterbatch prepared according to Example 6 is compounded using a throughput of 720 kg / h, a screw-shaft speed of 270 l / min, and a resulting non-mechanical energy input of 0.138 kWh / kg. The temperature of the melt discharged from the extruder is 299°C.

[0266] The surface of the three injection-molded sheets from the formulated molding mixture is cm 2 It has an average of 67 defects, an average defect diameter of 20.5 μm, and a maximum defect diameter of 116.3 μm.

[0267] The specific surface quality is 203 m -1 am.

[0268] Therefore, by using the polycarbonate masterbatch according to the present invention, it was possible to produce a molding formulation having improved specific surface quality without any change in throughput and without any increase in energy input compared to Comparative Example 5.

[0269] Process parameters and molding formulation characteristics for Experiment 1-6.1 (Comparative Example and Example according to the present invention) are summarized in Table 1.

[0270]

[0271]

Claims

Claim 1 A method for preparing a molding compound comprising the following components: 97 wt% to 36 wt% of polycarbonate, 3 wt% to 20 wt% of reinforcing filler, and 0 wt% to 61 wt% of other molding compound components, wherein the sum of the components is 100 wt%, wherein first, a masterbatch comprising the following components: 70 wt% to 25 wt% of polycarbonate, 30 wt% to 70 wt% of reinforcing filler, and 0 wt% to 5 wt% of other masterbatch components is prepared, wherein the sum of the components is 100 wt%, wherein the masterbatch is prepared in a continuous single-shaft kneader in the following steps: (1) adding polycarbonate and at least one reinforcing filler to a continuous single-shaft kneader, and (2) mixing polycarbonate and at least one reinforcing filler using a continuous single-shaft kneader, wherein the ratio of polyester in the masterbatch is 0.9 wt%. The following steps are performed, subsequently: (3) adding the masterbatch and polycarbonate to a blending unit; (4) blending the masterbatch and polycarbonate using the blending unit, wherein the reinforcing filler is titanium dioxide (TiO2) and talc (Mg3Si4O2). 10 (OH)2), dolomite (CaMg[CO3]2), kaolinite (Al4[(OH)8|Si4O2) 10 Selected from one or more members of the group consisting of ]), and wollastonite (Ca3[Si3O9]), or titanium dioxide (TiO2) and talc (Mg3Si4O2) 10 A method selected from one or more members of the group consisting of (OH)2), wherein the proportion of polyester in the molded compound is 0.9 weight% or less, or the proportion of polyester in the molded compound is 22 weight% or more and 58 weight% or less. Claim 2 A method according to claim 1, wherein the masterbatch comprises 35% to 65% by weight, or 40% to 60% by weight of reinforcing filler and 65% to 31% by weight, or 59.5% to 37% by weight of polycarbonate, and the sum of the components is 100% by weight. Claim 3 A method according to claim 1 or 2, wherein the masterbatch comprises 0 to 5 weight%, 0 to 4 weight%, or 0 to 3 weight% of other masterbatch components, and the sum of the components is 100 weight%. Claim 4 A method according to claim 1 or 2, wherein a reinforcing filler is added before melting the polycarbonate in step (2), after melting the polycarbonate, or both before and after melting the polycarbonate. Claim 5 A method according to claim 1 or 2, wherein the molding mixture comprises 4.5% to 15% by weight of reinforcing filler and 95.5% to 41% by weight of polycarbonate, and the sum of the components is 100% by weight. Claim 6 A method according to claim 5, wherein the molding mixture comprises 0% to 54.5% by weight or 0% to 25% by weight of other molding mixture components, and the sum of the components is 100% by weight. Claim 7 A method according to claim 1 or 2, wherein the mixing unit is selected from the group consisting of a continuous single-shaft kneader, a multi-shaft extruder, a twin-screw extruder, a ring extruder, a planetary roller extruder, a ram kneader, an internal mixer, and a co-rotating twin-screw extruder. Claim 8 A molded formulation prepared by the method claimed in paragraph 1 or 2. Claim 9 In paragraph 8, 550 m -1 Below, 300 m -1 Less than, or 250 m -1 A molding formulation suitable for manufacturing injection-molded articles having the following specific surface quality. Claim 10 In paragraph 8, a molded article, an article obtainable by injection molding, a film or sheet obtainable by extrusion of a molding compound, a light reflector, or a molding compound used for the manufacture of a structural part. Claim 11 550 m manufactured from the molding formulation as claimed in paragraph 8 -1 Below, 300 m -1 Less than, or 250 m -1 Injection-molded articles having the following specific surface quality.

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