EP4051497A1

EP4051497A1 - Layered composite comprising polycarbonate and a polycarbonate blend for improved paintability

Info

Publication number: EP4051497A1
Application number: EP20793725.1A
Authority: EP
Inventors: Christopher Schirwitz; Matthias KNAUPP; Marius Nolte; Ralf Hufen; Dirk Hinzmann; Sven SIEGEMUND; Uwe Klippert
Original assignee: Covestro Intellectual Property GmbH and Co KG
Current assignee: Covestro Intellectual Property GmbH and Co KG
Priority date: 2019-10-28
Filing date: 2020-10-28
Publication date: 2022-09-07
Also published as: CN114599518A; US20220371309A1; WO2021083925A1; KR20220095187A; EP3815898A1; JP2022554102A

Abstract

The present invention relates to a layered composite comprising a polycarbonate-based matrix, possibly containing fibres, and an outer layer of special polycarbonate-polyester blends, and also to a layered composite such as that described above and provided with painting on that side of its outer layer which is facing away from the matrix, to a method for producing these composites and also to their use for the production for example of automobile add-on parts.

Description

Layer composite made of polycarbonate and polycarbonate blend for improved paintability

The present invention relates to a layer composite of a polycarbonate-based matrix, optionally containing fibers, and a top layer of special polycarbonate-polyester blends, and a layer composite as described above, the top layer of which is provided with a coating on the side facing away from the matrix Production of these composites, as well as their use for the production of, for example, automobile add-on parts.

Polycarbonates, polycarbonate blends, for example based on PC and ASA or ABS, and polycarbonate composites, i.e. fiber-reinforced polycarbonates, have long been established in the automotive industry. They are used, for example, in the manufacture of automotive add-on parts. Due to their low weight, the weight of the vehicle components produced in this way is significantly reduced in comparison to corresponding vehicle components which were produced using conventional materials, and this while maintaining the same strength and safety. This can significantly reduce fuel consumption.

The plastic parts are coated with primer layers, so-called primers, to protect against environmental influences, and layers of lacquer to achieve optical or effect properties. When baking these coatings, bubbles, blisters, sink marks and cracks can form in the coating, as shown in the experimental section of this document. This is undesirable for aesthetic reasons and can also impair the protective effect of the coating.

The object of the present invention was to provide a polycarbonate-based system which can be provided with a coating, in particular a coating for automotive add-on parts, without the disadvantages of the prior art shown.

The problem was solved by a multi-layer structure made of a polycarbonate-based matrix and a top layer made of special polycarbonate-polyester blends.

The present invention relates to a layer composite comprising a substrate layer S and a cover layer D at least partially connected to the substrate layer S, wherein the material of the substrate layer S comprises a first thermoplastic polymer and the material of the cover layer D also comprises the first thermoplastic polymer, characterized in that the first thermoplastic polymer is an aromatic polycarbonate and in the material of the cover layer D the first thermoplastic polymer as a blend a polyester component P is present, i) the proportion of this polyester component P> 2% by weight, preferably> 5

% By weight, particularly preferably> 8% by weight, based on the

The total weight of the material of the outer layer D is, and the polyester component P comprises or consists of at least one polycycloalkylene terephthalate, ii) the proportion of this polyester component P> 10% by weight, preferably> 15

% By weight, particularly preferably> 17% by weight, based on the

The total weight of the material of the outer layer D is, and the polyester component P comprises or consists of at least one polyalkylene terephthalate, iii) the proportion of this polyester component P> 20% by weight, preferably> 30

% By weight, particularly preferably> 35% by weight, based on the

The total weight of the material of the outer layer D is, and the polyester component P comprises or consists of at least one polyalkylene naphthalate, iv) the proportion of this polyester component P> 2% by weight, preferably> 5

% By weight, particularly preferably> 8% by weight, based on the

Total weight of the material of the outer layer D, and wherein the polyester component P comprises a mixture or consists of a mixture of at least 2 of the following components: at least one polycycloalkylene terephthalate, at least one polyalkylene terephthalate, at least one polyalkylene naphthalate.

In variant iv), preference is given to using a mixture which comprises or consists of at least one polycycloalkylene terephthalate and at least one polyalkylene terephthalate, or - At least one polycycloalkylene terephthalate and at least one polyalkylene naphthalate, or

- At least one polyalkylene terephthalate and at least one polyalkylene naphthalate.

In variant iv) it is particularly preferred to use a mixture which comprises or consists of at least one polycycloalkylene terephthalate and at least one polyalkylene terephthalate. DE 202017004083 U1 discloses a multilayer structure made of a core based on a fiber-containing thermoplastic, which is preferably polypropylene or polyamide, and a cover layer made of a thermoplastic film, which is also preferably made of polypropylene or polyamide (claim 1, [0014], [0041]). Polycarbonate-based systems are not mentioned. The document also does not deal with the paintability of thermoplastics.

According to the above-mentioned subject matter according to the invention, component P comprises or consists of certain polyester components (see i) to iv)). In the “comprises” embodiment, the corresponding polyester component can contain, for example, impurities or other plastics, such as further polyesters, the latter not being those mentioned in the other polyester components. For example, embodiment i) describes a polyester component P which comprises one or more polycycloalkylene terephthalate (s). In this embodiment, polyalkylene terephthalates, for example, cannot additionally be contained in the polyester component. If polyalkylene terephthalates are also contained, this is to be treated as embodiment iv).

Description of the substrate layer S

For the purposes of the present invention, polycarbonates are both homopolycarbonates and copolycarbonates and / or polyester carbonates; the polycarbonates can be linear or branched in a known manner. Mixtures of polycarbonates can also be used according to the invention. The weight-average molecular weight M _{w of} the aromatic polycarbonates and polyester carbonates is in the range from 15,000 to 35,000, preferably in the range from 20,000 to 33,000, more preferably 23,000 to 31,000, determined by GPC (gel permeation chromatography in methylene chloride with polycarbonate as standard).

Some, up to 80 mol%, preferably from 20 mol% to 50 mol%, of the carbonate groups in the polycarbonates used according to the invention can be replaced by aromatic dicarboxylic acid ester groups. Such polycarbonates, which contain both acid residues of carbonic acid and acid residues of aromatic dicarboxylic acids built into the molecular chain, are referred to as aromatic polyester carbonates. In the context of the present invention, they are subsumed under the generic term of thermoplastic, aromatic polycarbonates.

The polycarbonates are produced in a known manner from diphenols, carbonic acid derivatives, optionally chain terminators and optionally branching agents, some of the carbonic acid derivatives being replaced by aromatic dicarboxylic acids or derivatives of dicarboxylic acids, depending on the amount to be replaced in the aromatic polycarbonates, to produce the polyester carbonates

Carbonate structural units by aromatic dicarboxylic acid ester structural units.

Dihydroxyaryl compounds suitable for the production of polycarbonates are those of the formula (1)

HO-Z-OH (1), in which Z is an aromatic radical with 6 to 30 carbon atoms, which can contain one or more aromatic nuclei, can be substituted and can contain aliphatic or cycloaliphatic radicals or alkylaryls or heteroatoms as bridge members .

Z in formula (1) is preferably a radical of the formula (2) in the

R ⁶ and R ⁷ independently of one another for H, Ci- to Cis-alkyl, Ci- to Cis-alkoxy, halogen such as Cl or Br or for each optionally substituted aryl or aralkyl, preferably for H or Ci- to Ci2-alkyl, particularly preferred for H or C1 to Cs-alkyl and very particularly preferably for H or methyl, and

X represents a single bond, -SO2-, -CO-, -O-, -S-, Ci- to C _ö alkylene, C2- to C5-alkylidene or C 5 to CVCycloalkylidcn which, with Ci- to Ce- alkyl preferably methyl or ethyl, can also be substituted for Ce- to C12-

Arylene, which can optionally be fused with further aromatic rings containing heteroatoms.

X is preferably a single bond, C _j to C ₅ alkylene, C ₂ to C ₅ alkylidene, C ₅ to C ₈ cycloalkylidene, -O-, -SO-, -CO-, -S-, -S0 ₂ - or for a radical of the formula (3a)

Examples of dihydroxyaryl compounds (diphenols) are: dihydroxybenzenes, dihydroxydiphenyls, bis (hydroxyphenyl) alkanes, bis (hydroxyphenyl) cycloalkanes, bis

(hydroxyphenyl) aryls, bis (hydroxyphenyl) ethers, bis (hydroxyphenyl) ketones, bis (hydroxyphenyl) sulfides, bis (hydroxyphenyl) sulfones, bis (hydroxyphenyl) sulfoxides, 1,1 ' - Bis- (hydroxyphenyl) -diisopropylbenzenes and their ring-alkylated and ring-halogenated compounds.

Diphenols suitable for producing the polycarbonates to be used according to the invention are, for example, hydroquinone, resorcinol, dihydroxydiphenyl, bis (hydroxyphenyl) alkanes, bis (hydroxyphenyl) cycloalkanes, bis (hydroxyphenyl) sulfides, bis (hydroxyphenyl) ethers, bis - (hydroxyphenyl) ketones, bis (hydroxyphenyl) sulfones, bis (hydroxyphenyl) sulfoxides, a, a'-bis (hydroxyphenyl) diisopropylbenzenes and their alkylated, ring alkylated and ring halogenated compounds.

Preferred diphenols are 4,4'-dihydroxydiphenyl, 2,2-bis- (4-hydroxyphenyl) -l-phenylpropane, 1,1-bis- (4-hydroxyphenyl) -phenylethane, 2,2-bis- (4-hydroxyphenyl) ) propane, 2,4-bis- (4-hydroxyphenyl) -2-methylbutane, 1,3-bis- [2- (4-hydroxyphenyl) -2-propyl] benzene

(Bisphenol M), 2,2-bis- (3-methyl-4-hydroxyphenyl) -propane, 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 and 1,3-bis- (4- h yd ro xyphcny I) - 3, 3, 5 - 1 rimcthy I cyc I ohexane (bisphenol TMC).

Particularly preferred diphenols are 4,4'-dihydroxydiphenyl, 1,1-bis- (4-hydroxyphenyl) -phenyl-ethane, 2,2-bis- (4-hydroxyphenyl) -propane, 2,2-bis (3,5 -dimethyl-4-hydroxyphenyl) -propane, 1,1-bis- (4-hydroxyphenyl) -cyclohexane and I, I -bis- (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane (Bisphenol TMC).

Most preferred is 2,2-bis (4-hydroxyphenyl) propane (bisphenol A).

These and other suitable diphenols are, for example, in US 2999 835 A, 3148 172 A, 2991 273 A, 3271 367 A, 4 982 014 A and 2 999 846 A, in German Offenlegungsschriften 1 570 703 A, 2 063 050 A, 2 036 052 A, 2 211 956 A and 3 832 396 A, the French patent specification 1 561 518 A1, in the monograph “H. Schnell, Chemistry and Physics of Polycarbonates, Interscience Publishers, New York 1964, p. 28 ff .; P.102 ff. ”, And in“ D.G. Legrand, J.T. Bendler, Handbook of Polycarbonate Science and Technology, Marcel Dekker New York 2000, pp. 72ff. “.

In the case of homopolycarbonates, only one diphenol is used; in the case of copolycarbonates, two or more diphenols are used. The diphenols used, as well as all other chemicals and auxiliaries added to the synthesis, can be contaminated with impurities from their own synthesis, handling and storage. However, it is desirable to work with raw materials that are as pure as possible.

The monofunctional chain terminators required to regulate the molecular weight, such as phenols or alkylphenols, in particular phenol, p-tert. Butylphenol, iso-octylphenol, cumylphenol, their chlorocarbonic acid esters or acid chlorides of monocarboxylic acids or mixtures of these chain terminators are either added to the reaction with the bisphenolate or bisphenolates or added at any point in the synthesis as long as phosgene or chlorocarbonic acid end groups are still in the reaction mixture are present, or in the case of the acid chlorides and chlorocarbonic acid esters as chain terminators, as long as sufficient phenolic end groups of the polymer being formed are available. Preferably, however, the chain terminator or terminators are added after the phosgenation at one point or at a time when no more phosgene is present but the catalyst has not yet been metered in, or they are metered in before the catalyst, together with the catalyst or in parallel. Any branching agents or branching mixtures to be used are added to the synthesis in the same way, but usually before the chain terminators. Usually trisphenols, quarter phenols or acid chlorides of tri- or tetracarboxylic acids or mixtures of the polyphenols or the acid chlorides are used.

Some of the compounds with three or more than three phenolic hydroxyl groups that can be used as branching agents are, for example, phloroglucinol, 4,6-dimethyl-2,4,6-tri- (4-hydroxyphenyl) -hepten-2, 4,6-dimethyl-2, 4,6-tri- (4-hydroxyphenyl) -heptane, 1,3,5-tris- (4-hydroxyphenyl) -benzene, l, l, l-tri- (4-hydroxyphenyl) -ethane, tris- (4 -hydroxyphenyl) - phenylmethane, 2,2-bis- [4,4-bis- (4-hydroxyphenyl) -cyclohexyl] -propane, 2,4-bis- (4-hydroxyphenyl-isopropyl) -phenol, tetra- (4 hydroxyphenyl) methane.

Some of the other trifunctional compounds are 2,4-dihydroxybenzoic acid, trimesic acid, cyanuric chloride, and 3,3-bis- (3-methyl-4-hydroxyphenyl) -2-oxo-2,3-dihydroindole.

Preferred branching agents are 3,3-bis- (3-methyl-4-hydroxyphenyl) -2-oxo-2,3-dihydroindole and 1,1,1-tri (4-hydroxyphenyl) ethane.

The amount of branching agents to be used, if appropriate, is 0.05 mol% to 2 mol%, again based on the moles of diphenols used in each case.

The branching agents can either be initially introduced with the diphenols and the chain terminators in the aqueous alkaline phase or dissolved in an organic solvent and added before the phosgenation.

Ahe skilled in the art is familiar with these measures for producing the polycarbonates.

Aromatic dicarboxylic acids suitable for preparing the polyester carbonates are, for example, orthophthalic acid, terephthalic acid, isophthalic acid, tert-butyl isophthalic acid, 3,3'-diphenyldicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-benzophenonedicarboxylic acid, 3,4'-benzophenonedicarboxylic acid, 4,4 '-Diphenyletherdicarboxylic acid, 4,4'-

Diphenylsulfonedicarboxylic acid, 2,2-bis- (4-carboxyphenyl) -propane, trimethyl-3-phenylindan-4,5'-dicarboxylic acid.

Of the aromatic dicarboxylic acids, terephthalic acid and / or isophthalic acid are particularly preferably used. Derivatives of the dicarboxylic acids are the dicarboxylic acid dihalides and the dicarboxylic acid dialkyl esters, in particular the dicarboxylic acid dichlorides and the dicarboxylic acid dimethyl esters.

The replacement of the carbonate groups by the aromatic dicarboxylic acid ester groups takes place essentially stoichiometrically and also quantitatively, so that the molar ratio of the reactants is also found in the finished polyester carbonate. The incorporation of the aromatic dicarboxylic acid ester groups can take place either randomly or in blocks.

Preferred methods of production of the polycarbonates to be used according to the invention, including the polyester carbonates, are the known interfacial process and the known melt transesterification process (cf., for example, WO 2004/063249 A1, WO 2001/05866 A1, WO 2000/105867, US Pat 5,097,002 A, US-A 5,717,057 A).

In the first case, the acid derivatives used are preferably phosgene and optionally dicarboxylic acid dichlorides, in the latter case preferably diphenyl carbonate and optionally dicarboxylic acid diesters. Catalysts, solvents, work-up, reaction conditions, etc. for the production of polycarbonate or polyester carbonate are adequately described and known in both fields.

The material of the substrate layer S can also contain plastics other than polycarbonate as blend partners.

As blend partners, polyamides, polyesters, in particular polybutylene terephthalate and polyethylene terephthalate, polylactide, polyether, thermoplastic polyurethane, polyacetal, fluoropolymer, in particular polyvinylidene fluoride, polyether sulfones, polyolefin, in particular polyethylene and polypropylene, polyimide, polyacrylate, in particular poly (methyl) methacrylate, polyphenylene oxide , Polyether ketone, polyaryl ether ketone, styrene polymers, especially polystyrene, styrene copolymers, especially styrene acrylonitrile copolymers, acrylonitrile butadiene styrene block copolymers and polyvinyl chloride. The blend partners are used in amounts of preferably a maximum of 70% by weight, particularly preferably a maximum of 50% by weight, very particularly preferably a maximum of 35% by weight based on the total weight of polycarbonate and blend partner.

In addition, up to 10.0% by weight, preferably 0.10 to 8.0% by weight, particularly preferably 0.2 to 3.0% by weight, based on the total weight of the material of the substrate layer, are other customary ones Contains additives. This group includes flame retardants, anti-dripping agents, thermal stabilizers, mold release agents, antioxidants, UV absorbers, IR absorbers, antistatic agents, optical brighteners, light scattering agents, colorants such as pigments, including inorganic pigments, carbon black and / or dyes, and inorganic fillers in the usual polycarbonate materials Amounts. These additives can be added individually or as a mixture.

Such additives, as they are usually added to polycarbonates, are for example in EP-A 0 839 623, WO-A 96/15102, EP-A 0 500 496 or “Plastics Additives Handbook”, Hans Zweifel, 5th Edition 2000, Hanser Verlag , Munich. The substrate layer can contain one or more reinforcement fiber layers made of a fiber material. This creates fiber-containing composite materials, hereinafter referred to as fiber composite materials. The substrate layer S can also consist of several layers of fiber composite material and is then referred to as a multilayer composite material.

Fiber composite

The chemical structure of the fibers of the fiber material can be of the most varied of types. The fiber materials have a higher softening or melting point than the thermoplastic matrix material present in each case. The fiber material used is preferably coated with suitable sizes.

In one embodiment of the fiber composite material, the fiber layer is designed as a unidirectional fiber layer, as a woven or gauze layer, as a knitted fabric, knitted fabric or braid, as random fiber mats or fleeces or as a combination thereof. In tests, the best properties of fiber composite materials were achieved with unidirectional fiber layers, fabrics and scrims.

Unidirectional in the context of the invention means that the fibers are aligned essentially unidirectionally, that is to say point lengthwise in one direction and thus have the same running direction. With “essentially unidirectional” it is meant here that a deviation of the grain direction of up to 5% is possible. However, the deviation in the grain direction is preferably well below 3%, particularly preferably well below 1%.

The fiber material can be present as short fibers (length <1mm), as long fibers (1 to 50 mm) or as continuous fibers (> 50 mm). It is preferably in the form of long fibers or continuous fibers in front. According to the invention, the fiber material is preferably ground fibers or chopped glass fibers. “Available” means that it can also be a mixture with other fiber materials. However, the respective fiber material is preferably the only fiber material.

The term “continuous fiber” is to be understood in the sense of the invention as a delimitation from the short or long fibers likewise known to the person skilled in the art. Continuous fibers usually extend over the entire length of the layer of fiber composite material. The term continuous fiber is derived from the fact that these fibers are wound up on a roll and are unwound and impregnated with plastic during the production of the individual fiber composite material layers, so that, with the exception of occasional breakage or roll changes, their length is usually essentially the same as the length of the manufactured fiber composite material layer matches.

Examples of fiber materials are inorganic materials such as silicate and non-silicate glasses of various types, carbon, basalt, boron, silicon carbide, metals, metal alloys, metal oxides, metal nitrides, metal carbides and silicates, as well as organic materials such as natural and synthetic polymers, for example polyacrylonitriles, polyesters, ultra-vertically oriented ones Polyamides, polyimides, aramids, liquid crystalline polymers, polyphenylene sulfides, polyether ketones, polyether ether ketones, polyether imides. High-melting materials, for example glasses, carbon, aramids, basalt, liquid crystal polymers, polyphenylene sulfides, polyether ketones, polyether ether ketones and polyether imides are preferred. Particularly preferred fiber materials are glass fibers or carbon fibers.

A layer of fiber material, also referred to as a fiber layer, is understood to be a flat layer which is formed by fibers arranged essentially in a surface. The fibers can be connected to one another by their position to one another, for example by a fabric-like arrangement of the fibers. Furthermore, the fiber layer can also have a proportion of resin or another adhesive in order to connect the fibers to one another. Alternatively, the fibers can also be unconnected. This is understood to mean that the fibers can be detached from one another without the application of any significant force. The fiber layer can also have a combination of connected and unconnected fibers. At least one side of the fiber layer is embedded in the polycarbonate-based compositions used according to the invention as a matrix material. This is understood to mean that the fiber layer is surrounded at least on one side, preferably on both sides, by the polycarbonate-based composition. The outer edge of the fiber composite material is preferably formed by the matrix made of a polycarbonate-based composition. The number of fiber layers in a layer of fiber composite material is basically not restricted. Two or more fiber layers can therefore also be arranged one above the other. Two fiber layers lying one above the other can each be embedded individually in the matrix material so that they are each surrounded on both sides by the matrix material. Furthermore, two or more fiber layers can also lie directly on top of one another, so that their entirety is surrounded by the matrix material. In this case, these two or more fiber layers can also be viewed as one thick fiber layer.

Multilayer composites Multilayer composites and materials have at least two, preferably at least three superimposed layers of fiber composite material, whereby in the case of three composite material layers these are defined relative to one another as two outer layers of fiber composite material and at least one inner layer of fiber composite material. The preferred fiber material in the layers of fiber composite material are continuous fibers, which are preferably aligned unidirectionally.

In the case of continuous fibers as fiber material, the inner layers of fiber composite material can be oriented essentially identically and their orientation relative to the outer layers of fiber composite material can be rotated by 30 ° to 90 °, the orientation of a layer of fiber composite material being determined by the orientation of the unidirectional fibers contained therein becomes.

In a preferred embodiment, the layers are arranged alternately. The outer layers are in a 0 ° orientation. It has proven to be particularly practical if the inner layers of fiber composite material are oriented in the same way and their orientation is rotated by 90 ° relative to the outer layers of fiber composite material. “Alternating” means that the inner layers are arranged alternately at an angle of 90 ° or an angle of 30 ° to 90 °. The outer layers are each in a 0 ° orientation. The angles can be varied from 30 ° to 90 ° for each position. Another preferred embodiment is that at least some of the layers have the same orientation and at least one other part of the layers is rotated by 30 ° to 90 °. The outer layers are in a 0 ° orientation. Another preferred embodiment is that the inner layers have the same orientation and their orientation relative to the outer layers of laser composite material is rotated by 30 ° to 90 ° and the outer layers are in a 0 ° orientation for this purpose.

The layers of laser composite materials are stacked alternately in the warp direction (0 °) and weft direction (90 °) or at the angles indicated above in the Lalle of fabrics.

The laser or multilayer composite materials can have a metallic sound. They also have the advantage that they can be manufactured inexpensively and are extremely lightweight due to the plastic used therein. Another advantage of the laser or multilayer composite materials is that the design, for example of a housing part, can be particularly simple and flexible due to the thermoformability of the composite materials.

In principle, the multilayer composite material according to the invention can also contain one or more further layers in addition to the layers of laser composite material. Additional layers made of plastic, which can be identical to or different from the plastic matrix used in the layers of laser composite material, may be mentioned here by way of example. These plastic layers can in particular also contain fillers that are different from the laser materials provided according to the invention. Learner can also be included in the multilayer composite material according to the invention, adhesive, fabric, fleece or surface coating layers, for example lacquer layers. These further layers can be contained between inner and outer layers of laser composite material, between several inner layers of laser composite material and / or on the outer layer of laser composite material, which is on the side facing away from cover layer D. However, the outer layer and the at least one inner layer of laser composite material are preferably connected to one another in such a way that no further layers lie between them.

The individual layers of laser composite material can be constructed and / or oriented essentially identically or differently.

In the context of the invention, an essentially identical structure of the layers of laser composite material is understood to mean that at least one feature from the group of chemical composition, laser volume content and layer thickness is the same. Chemical composition is understood to mean the chemical composition of the plastic matrix of the fiber composite material and / or the chemical composition of the fiber material such as continuous fibers.

According to a preferred embodiment of the invention, the outer layers of fiber composite material have essentially the same structure with regard to their composition, their fiber volume content and their layer thickness.

The multilayer composite material preferably has a total thickness of 0.4 to 2.5 mm, preferably 0.7 to 1.8 mm, in particular 0.9 to 1.2 mm. Practical tests have shown that it is possible with the multilayer composite material according to the invention to achieve extremely good mechanical properties even with these small thicknesses.

It has proven to be particularly advantageous if the sum of all inner layers of fiber composite material has a total thickness of 200 μm to 1200 μm, preferably 400 μm to 1000 μm, particularly preferably 500 μm to 750 μm.

It is also advantageous within the scope of the invention if the thickness of each of the two outer layers of fiber composite material is 100 to 250 μm, preferably 120 μm to 230 μm, particularly preferably 130 μm to 180 μm.

Fiber composite layers preferred according to the invention have a fiber volume content of> 30% by volume and <60% by volume, preferably> 35% by volume and <55% by volume, particularly preferably> 37% by volume and <52% by volume. -% on. A fiber volume content of over 60% by volume leads to a deterioration in the mechanical properties of the fiber composite material. Without wishing to be bound by scientific theories, this seems to be due to the fact that the fibers can no longer be adequately wetted during impregnation with such high fiber volume contents, which leads to an increase in air inclusions and an increased occurrence of surface defects in the fiber composite material, and more significantly Reduction of the mechanical load capacity leads.

In one embodiment of the multilayer composite material, the volume content of the fiber material in the total volume of the multilayer composite material is in the range from 30 to 60% by volume, preferably in the range from 40 to 55% by volume.

According to one embodiment of the invention, the outer layers of fiber composite material have a fiber volume content of at most 50% by volume, preferably at most 45% by volume, in particular at most 42% by volume. According to a particular embodiment of the invention, the outer layers of fiber composite material have a fiber volume content of at least 30% by volume, preferably at least 35% by volume, in particular at least 37% by volume.

According to a further particular embodiment of the invention, the outer layers of fiber composite material have a lower volume content of fibers, based on the total volume of the layer of fiber composite material, than the at least one inner layer of fiber composite material.

The inner layers of fiber composite material can have a fiber volume content of 40 to 60% by volume, preferably 45 to 55% by volume, particularly preferably 48 to 52% by volume, based on the total volume of the fiber composite material layer.

Vol .-% is understood here to mean the volume fraction (% v / v) based on the total volume of the layer of fiber composite material.

Manufacture of the fiber composite materials and the multilayer composite materials The manufacture of the fiber composite materials or multilayer composite materials to be used according to the invention as the substrate layer S are known to the person skilled in the art and are described, for example, in EP3464471 A1 and EP3055348 B1.

Description of the top layer D

The material of the cover layer D comprises the aromatic polycarbonate, which is also contained in the substrate layer S as a blend with a polyester component P which comprises poly (cyclo) alkylene terephthalates and polyalkylene naphthalates or mixtures of these polyesters according to the statements of claim 1. These polyesters are reaction products of terephthalic acid or

Naphthalene-2,6-dicarboxylic acid or its reactive derivatives, such as, for example, the dimethyl esters of these two acids, and aliphatic or cycloaliphatic diols.

For the preparation of the polyalkylene terephthalates and naphthalates, preference is given to using (ar) aliphatic diols with 3 to 12 carbon atoms, such as, for example: Ethylene glycol, 1,4-butanediol, 1,3-propanediol, 2-ethylpropanediol-1,3, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, 3-ethylpentanediol-2,4, 2-methylpentanediol-2, 4, 2,2,4-trimethylpentanediol-1,3, 2-ethylhexanediol-1,3, 2,2-diethylpropanediol-1,3, hexanediol-2,5, 1,4-di- (ß-hydroxyethoxy) - benzene, 2,2-bis- (4-ß-hydroxyethoxyphenyl) propane and / or

2.2-bis (4-hydroxypropoxyphenyl) propane. Ethylene glycol and 1,4-butanediol are preferred.

For the preparation of the polycycloalkylene terephthalates, preference is given to using cycloaliphatic diols with 6 to 21 carbon atoms, such as, for example: cyclohexane-1,4-dimethanol,

2,2-bis (4-hydroxycyclohexyl) propane and / or 2,2,4,4-tetramethyl-1,3cyclobutanediol. Cyclohexane-1,4-dimethanol and 2,2,4,4-tetramethyl-1,3-cyclo-butanediol and mixtures thereof are preferred.

Particularly preferred polyalkylene terephthalates or naphthalates contain at least 80% by weight, preferably at least 90% by weight, based on the dicarboxylic acid component, terephthalic acid residues or naphthalene-2,6-dicarboxylic acid residues and at least 80% by weight, preferably at least 90 mol- %, based on the diol component, ethylene glycol and / or 1,4-butanediol residues.

Particularly preferred polycycloalkylene terephthalates contain at least 80% by weight, preferably at least 90% by weight, based on the dicarboxylic acid component tere phthalic acid residues and at least 80% by weight, preferably at least 90 mol%, based on the diol component cyclohexane-dimethanol-1, 4- and / or 2,2,4,4-tetramethyl-1,3cyclobutanediol residues.

The preferred poly (cyclo) alkylene terephthalates or polyalkylene naphthalates can contain, in addition to terephthalic acid residues or naphthalene-2,6-dicarboxylic acid residues, up to 20 mol%, preferably up to 10 mol%, residues of other aromatic or cycloaliphatic dicarboxylic acids having 8 to 14 carbon atoms or aliphatic dicarboxylic acids with 4 to 12 carbon atoms, such as residues of phthalic acid, isophthalic acid, 4,4'-diphenyldicarboxylic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, cyclohexanediacetic acid.

The preferred polyalkylene terephthalates or naphthalates can contain, in addition to ethylene glycol or butanediol 1,4 radicals, up to 20 mol%, preferably up to 10 mol%, of other (ar) aliphatic diols with 3 to 12 carbon atoms, For example, residues of 1,3-propanediol, 2-ethylpropanediol-1,3, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, 3-ethylpentanediol-2,4, 2-methylpentanediol-2,4,2 , 2,4-trimethylpentanediol-1,3,2-ethylhexanediol 1,3, 2,2-Diethylpropanediol-1,3, hexanediol-2,5, 1,4-di- (ß-hydroxyethoxy) -benzene, 2,2-bis- (4-ß-hydroxyethoxyphenyl) - propane and 2,2-bis (4-hydroxypropoxyphenyl) propane.

In addition to cyclohexane-1,4-dimethanol and / or 2,2,4,4-tetramethyl-1,3cyclobutanediol radicals, the preferred polycycloalkylene terephthalates can contain up to 20 mol%, preferably up to 10 mol%, of other cyclo aliphatic diols Contain 6 to 21 carbon atoms, for example residues of 2,2-bis (4-hydroxycyclohexyl) propane.

The above-mentioned polyesters can be branched by incorporating relatively small amounts of 3- or 4-valent alcohols or 3- or 4-basic carboxylic acids, e.g. according to DE-A 1 900270 and US Pat. No. 3,692,744. Examples of preferred branching agents are trimesic acid, trimellitic acid, trimethylol ethane and propane and pentaerythritol.

Very particularly preferred polyalkylene terephthalates are based solely on terephthalic acid or its reactive derivatives (e.g. its dialkyl esters) and ethylene glycol or 1,4-butanediol.

Very particularly preferred polycycloalkylene terephthalates are based solely on terephthalic acid or its reactive derivatives (e.g. its dialkyl esters) and cyclohexanedimethanol-1,4 and / or 2,2,4,4-tetramethyl-1,3cyclobutanediol.

Very particularly preferred polyalkylene naphthalates are based solely on naphthalene-2,6-dicarboxylic acid or its reactive derivatives (e.g. their dialkyl esters) and ethylene glycol or 1,4-butanediol.

The poly (cyclo) alkylene terephthalates and polyalkylene naphthalates can be produced by known methods (see e.g. Kunststoff-Handbuch, Volume VIII, pp. 695 ff., Carl-Hanser-Verlag, Munich 1973).

The proportion of polyester component P is very particularly preferably> 30% by weight, even more preferably> 35% by weight, based on the total weight of the material of the outer layer D, provided that polyester component P according to variant i) comprises or consists of at least one polycycloalkylene terephthalate. The proportion of the polyester component P is very particularly preferably> 30% by weight, even more preferably> 35% by weight, based on the total weight of the material Cover layer D, provided that polyester component P according to variant ii) comprises or consists of at least one polyalkylene terephthalate.

The proportion of polyester component P is moreover preferably> 45% by weight, most preferably> 50% by weight, based on the total weight of the material of the outer layer D, provided that polyester component P according to variant ii) comprises or consists of polyethylene terephthalate.

The proportion of the polyester component P for all embodiments is preferably <60, particularly preferably <55% by weight, based on the total weight of the material of the cover layer D. The material of the cover layer can contain further blend partners. As blend partners, polyamides, polyesters different from the polyesters described above, polylactide, polyether, thermoplastic polyurethane, polyacetal, fluoropolymer, in particular polyvinylidene fluoride, polyether sulfones, polyolefin, in particular polyethylene and polypropylene, polyimide, polyacrylate, in particular poly (methyl) methacrylate, polyphenylene oxide, Use polyphenylene sulfide, polyether ketone, polyaryl ether ketone, styrene polymers, especially polystyrene, styrene copolymers, especially styrene-acrylonitrile copolymers, acrylonitrile-butadiene-styrene block copolymers and polyvinyl chloride. In addition, up to 10.0% by weight, preferably 0.10 to 8.0% by weight, particularly preferably 0.2 to 3.0% by weight, based on the total weight of the material of the top layer D, contain other common additives. At this point, reference is made to the comments on the additives under the description of the substrate layer. The cover layer D has a thickness <500 mih, preferably <300 mih, particularly preferably <200 mih, very particularly preferably <100 mih.

The cover layer D has a thickness> 5 mhi, preferably> 10 mhi.

Description of the lacquer layer L

Lacquer is the name for a liquid or powdery coating material that is applied thinly to objects and by chemical or physical means Processes (for example evaporation of the solvent) is built up into a continuous, solid film.

All lacquers known to the person skilled in the art for use on polycarbonate-containing substrates are suitable as lacquer layer L. In a preferred embodiment, it is a lacquer for the field of automotive add-on parts, the lacquer layer L preferably comprising one or more of the following layers:

- at least one primer layer G,

- At least one basecoat layer B

- at least one clear coat K.

In the automotive sector, a primer layer is understood to mean coatings that optimize the adhesive strength of paints on plastic parts, for example even after weathering. The plastic parts are usually coated with a primer, also called a primer, before the color and effect paint layer or layers are applied. In addition to the adhesive strength, the primer should also help protect against falling rocks. Furthermore, a primer can be made conductive by adding appropriate additives such as conductive carbon black, so that the subsequently applied layers can be applied by means of electrostatic spray application and thus with particularly high transfer efficiency.

Basecoat (basecoat) is a name for a color-imparting intermediate coating material customary in automotive painting.

A clear coat (clear coat layer) protects the base coat from the effects of the weather, as well as mechanical and chemical attacks.

The number of basecoat layers and clearcoat layers to be applied is in each case not limited to one layer. It is also possible to apply two, three, four or more layers of basecoat or alternating layers of basecoat and clearcoat. The individual layers can each be dried completely or only partially dried before the next layer is applied. The latter is also known as the “wet-on-wet” application. Even when overcoating with a clear lacquer, the number of layers is not limited to one.

All primers, basecoats and topcoats known to the person skilled in the art, aqueous or based on organic solvents, can be used to produce the lacquer layer L. Examples of primer layers G that can be used according to the invention can be found, for example, in EP-B 1226218 or the European patent application with the application number 18213389.2, which was still unpublished at the time the present invention was applied for. A description of basecoat films B which can be used according to the invention can be found, for example, in US-A-3,639,147, DE-A-33 33 072, DE-A-38 14 853, GB-A-2012 191, US-A-3,953,644, EP-A -260 447, DE-A-39 03 804, EP-A-320 552, DE-A-36 28 124, US-A-4,719,132, EP-A-297 576, EP-A-69 936, EP-A -89 497, EP-A-195 931, EP-A-228 003, EP-A-38 127, DE-A-28 18 100 and WO-A 2017/202692.

Clear lacquer layers K which can be used according to the invention are described, for example, in EP-A 3445827 and WO-A 2017/202692.

Another object of the present invention is a method for producing a layer composite, comprising the step:

I) connecting a substrate layer S to a cover layer D, the substrate layer S and the cover layer D corresponding to the previous descriptions. Another subject matter is a method, as described above, further comprising the step:

II) Application of at least one lacquer layer to the side of the top layer D facing away from the substrate layer S in the layer composite obtained after step I). The layer composites according to the invention are used for the production of, for example, automobile add-on parts.

Further objects of the present invention are therefore the use of the layer composites according to the invention for the production of automobile add-on parts, and the automobile add-on parts themselves obtainable therefrom. Examples

The present invention is illustrated in more detail by the following examples, without, however, being restricted thereto. Production of the substrate S:

For the experiments, plates of a composite material made of polycarbonate and carbon fiber (hereinafter referred to as composite) with the dimensions 350 × 350 mm ^{2 were used} as the substrate layer. The composites were produced by Covestro Thermplast Composite GmbH (CTC) from 8 layers of UD tape, whereby the UD tapes themselves are made from 40-45% by volume of unidirectional carbon fiber of the Mitsubishi TRH-50 60M type and 60-55% by volume. Polycarbonate matrix (type Makroion® 3107 in color 901510). A general description of the production can be found, for example, in WO 2018/007335 A1.

In relation to the angular orientation of the carbon fibers, the layer structure in the individual UD tape layers was chosen so that there was a quasi-isotropic reinforcement of the composite (0745 ° / -45 ° / 90 ° / 90 ° / -45 ° / 45 ° / 0 °).

Production of the top layer D:

Thermoplastic molding compositions containing components A to E with the formulations given in Table 1 were produced on a ZSK25 twin-screw extruder from Coperion, Werner and Pfleiderer (Germany) at melt temperatures of 250.degree. C. to 300.degree. Films with a thickness of about 100 μm were then extruded from the granules obtained. For this purpose, the corresponding material was pre-dried (4 h, 85-90 ° C) on the extruder (speed approx. 50 / min, melt temperature 265 ° C (entries 1-16 in table 1) and 300 ° C (entry 17 in table 1)) melted and extruded onto a rolling mill through a 450 mm wide slot nozzle.

Components used in top layer D:

Component A: linear bisphenol A polycarbonate with an average molecular weight Mw of approx. 31,000 g / mol and a softening temperature (VST / B 120 according to ISO 306: 2014-3) of 150 ° C, which does not contain any UV absorber. The melt Volume flow rate (MVR) according to ISO 1133: 2012-03 was 6.0 cm ³ / (10 min) at 300 ° C and 1.2 kg load.

Component B1: Polybutylene terephthalate (PBT) with a melt-mass flow rate (MFR) of 9.0g / 10min to 14.5g / 10min measured according to DIN EN ISO 1133 at a temperature of 250 ° C and with a load of 2.16 kg.

Component B2: polyethylene terephthalate (PET) with an intrinsic viscosity of 0.623 dl / g. The specific viscosity is measured in dichloroacetic acid in a concentration of 1% by weight at 25 ° C. The intrinsic viscosity is calculated from the specific viscosity according to the following formula: Intrinsic viscosity = specific viscosity · 0.0006907 + 0.063096

Component B3: Polyester based on terephthalic acid, cyclohexanedimethanol and 2,2,4,4-tetramethyl-1,3-cyclobutanediol with an inherent viscosity of 0.69-0.75 dl / g measured in a 60/40 mixture (% by weight /% By weight) of phenol / tetrachloroethane at 25 ° C in a concentration of 0.5 g / 100 ml. Component B4: polyethylene naphthalate (PEN).

Component C: impact modifier with core-shell morphology, a styrene-butadiene-rubber core and a grafted-on shell made of methyl methacrylate-styrene copolymer, a butadiene content of 68% - 72% and a rubber

Particle size distribution between 130 nm and 160 nm. Component Dl: Talc with an average particle diameter dso of 1.2 μm, measured by means of Sedigraph and with an APO content of 0.5% by weight.

Component D2: Irganox 1076, thermal stabilizer, BASF SE

Component D3: Phosphorous acid H ₃ PO ₃ as a solid.

Component E: Pentaerythrityl tetrastearate as a lubricant / mold release agent.

The composites (substrate) were then laminated on both sides of a static laboratory press (type Joos LAP 100) with the films to be examined (cover layer D). A polished insert (“high-gloss stamp”) and an external release agent (Frekote®, Henckel) were used.

Production of the lacquer layer L Substances used to produce the primer, basecoat and clearcoat:

Unless otherwise stated, the substances were used without further purification or pretreatment.

Additol XL 250, Allnex Resins Germany GmbH, DE, anionic wetting and dispersing agent for pigments

Aerosil® R 972, Evonik Resource Efficiency GmbH, DE, fumed silica matting agent

Aquatix 8421, BYK Chemie GmbH, DE, rheology-modifying wax emulsion Bayferrox® 318 M, Lanxess AG, DE, iron oxide pigment

Bayhydrol® U 2757, Covestro AG, DE, aliphatic, anionic, hydroxy-functional polyurethane dispersion based on a mixture of aromatic polyester diol and a polycarbonate diol, co-solvent-free. Binder for the production of water-thinnable 2K-PUR lacquers, approx. 52% in water / N, N-dimethylethanolamine, hydroxyl content approx. 1.8% (calculated) based on the non-volatile content (1 g / 1 h / 125 ° C ) according to DIN EN ISO 3251, information according to data sheet edition 2016-09-13.

Bayhydrol® UH 2606, Covestro AG, DE, aliphatic, polycarbonate-containing anionic polyurethane dispersion, co-solvent-free. Binder for the production of water-thinnable coatings for plastic substrates and wood-based materials, approx. 35% in water, neutralized with N-ethyldiisopropylamine (bound as salt) in the ratio: approx. 35: 64: 1, information according to data sheet edition 2016-09-13.

Bayhydrol® UA 2856 XP, Covestro AG, DE, Aliphatic, acrylate-modified polyurethane dispersion Binder for aqueous, air- and oven-drying basecoats for 2-layer vehicle painting, plastic painting, automotive refinishing, industrial painting and for low-temperature-drying stone chip functional layers.

Viscosity <100 mPa s at 23 ° C (ISO 3219 / A.3), information according to data sheet edition 2016-03-03

Bayhydur® XP 2655, Covestro AG, DE, hydrophilic polyisocyanate based on trimers of hexamethylene diisocyanate, NCO content 20.8% (ISO 11909), viscosity 3500 mPa s at 23 ° C (ISO 3219 / A.3), information in accordance with Data sheet edition 2017-06-01. Baysilone® Paint Additive OL 17, OMG Borchers, DE, polyether-modified polysiloxane (leveling additive)

Blanc fixe micro, Sachtleben Chemie GmbH, DE, filler Borchigel® PW 25, OMG Borchers, DE, polyurethane thickener butyl acetate (n-butyl acetate), Azelis Deutschland GmbH, solvent butyl glycol (2-butoxyethanol), BASF SE, DE, solvent

Byk® 348, BYK Chemie GmbH, DE, silicone surfactant to improve substrate wetting

Desmodur® ultra N 3390, Covestro AG, DE, aliphatic polyisocyanate (trimer of hexamethylene diisocyanate). As a hardener component for lightfast polyurethane paint systems.

NCO content 19.6% (ISO 11909), viscosity 500 mPa s at 23 ° C (ISO 3219 / A.3), information according to data sheet edition 2018-11-14.

Desmodur® ultra N 3600, Covestro AG, DE, polyisocyanate based on trimers of hexamethylene diisocyanate, NCO content 23.0% (ISO 11909), viscosity 1200 mPa s at 23 ° C (ISO 3219 / A.3), information in accordance with Data sheet edition 2017-06-01.

Desmophen® 670 BA, Covestro AG, DE, slightly branched polyester containing hydroxyl groups for the production of weatherproof, elastic coatings.

Viscosity 3000 mPa s at 23 ° C (ISO 3219 / A.3), information according to data sheet edition 2018-03-01

Diacetone Alcohol (DAA), Acros Organics, Solvent

Dibutyltin dilaurate, ISO-ELEKTRA - Elektrochemische Fabrik GmbH, catalyst N, N-dimethylethanolamine (DMEA), Sigma Aldrich Chemie, DE, neutralizing agent Dispex® Ultra FA 4436, BASF SE, DE, dispersing aid Finntalc® M-15 AW, Mondo Minerals BV, NL, talc l-methoxy-2-propyl acetate (MPA), BASF SE, DE, solvents

R-KB-2, Sachtleben Chemie GmbH, DE, white pigment Setalux® DA 365 BA / X, Allnex Resins Germany GmbH, DE, functional acrylic polymer-containing binder

Setaqua 6801, Allnex Belgium SA / NV, non-functional acrylate-containing copolymer

Solvent Naphtha 100 (heavy benzene), Azelis Deutschland GmbH, Solvent Stapa Hydrolan 2156 No. 55900 / G Aluminum, Eckart GmbH, DE, aluminum pigment paste

Surfynol® 104 E, Evonik Resource Efficiency GmbH, DE, non-ionic wetting, defoaming and dispersing aid

Tinuvin® 292 and Tinuvin® 1130, BASF SE, DE, UV stabilizers

Paint formulations:

Primer (aqueous, two-component plastic primer PCO-0148-PS according to the starting formulation published by Covestro Deutschland AG (Edition 2016-09-13)):

To produce component 1, the binder was initially introduced and then the other ingredients were weighed in in the order shown, glass beads (2.85 - 3.45 mm) were added 1: 1 (by volume) and then shaken with a Skandex BA laboratory shaker for 30 minutes. S20 from Lau rubbed. The glass beads were then sieved off. While stirring with a dissolver (dissolver disk 5 cm, at 800 rpm), the thickener was then slowly metered in and stirred in for a further 5 minutes. Component 1 was then adjusted with demineralized water to a flow time in the 4 mm DIN cup of 25 to 30 s.

Shortly before application, component 2 was incorporated while stirring with a paddle stirrer (5 min, 700 rpm) and the ready-to-use primer was applied within 30 minutes.

Table 1

Water-based metallic basecoat (one-component hydro-basecoat HEBE 4134/1 according to the starting formulation published by Covestro Deutschland AG (Edition 2016-08-23): First, the metallic paste (Table 2, Part 3) was prepared in a separate container all ingredients in table 2, part 3, mixed in the specified order while stirring with a propeller stirrer. The pH value was then tested (target: pH 8.0-8.5) and, if necessary, adjusted with DMEA. After stirring again for 30 minutes at approx. 10.5 m / s (maximum heating to 50 ° C) the paste was ready for use. For the metallic basecoat, part 1 and part 2 from Table 2 were mixed with a propeller stirrer at approx. 5.2 m / s. Part 3 was then added and stirred in for 30 minutes at about 10.5 m / s. Finally, part 4 was added and stirred in again for 5 minutes at 5.2 m / s. Before application, the pH of the paint was adjusted to 8.0-8.5 with DMEA. The outflow time was set to 40 seconds in accordance with DIN cup 4 mm with demineralized water and the paint was filtered off through a 56 μm sieve.

Table 2 Clearcoat (solvent-based clearcoat RR 4822 according to the starting formulation published by Covestro Deutschland AG (Edition 2015-09-01):

To produce component 1, the binders were initially introduced. While stirring with a dissolver (dissolver disk 5 cm, at 800 rpm), all the other components in Table 3, Part 1, are metered in in the order given and stirred in for a further 5-10 minutes.

Shortly before application, component 2 was incorporated while stirring with a paddle stirrer (5 min, 700 rpm) and the ready-to-use clearcoat was applied within 30 minutes.

Table 3

Painting of the substrate-top layer laminates The procedure for the production of the paint formulations and subsequent painting of the substrate-top layer laminates is described, inter alia, in the European patent application with the application number 18213389.2, which was still unpublished at the time of the application of the present invention. First, the aqueous, two-component plastic primer was prepared as described above and applied over the entire surface with a Satajet RP gravity gun, 1.3 mm, air pressure 2.1 bar in 1 cross-pass to create a layer thickness (dry) of 20-25 μm. After application, the primer was dried for 10 min at room temperature, 30 min at 80 ° C. in a convection oven and stored for 16 h at room temperature.

The one-component hydro-base paint was then prepared as described above and also applied over the entire surface with a Satajet HVLP gravity gun, 1.2 mm, air pressure 2.1 bar in 1 cross-pass to produce a layer thickness (dry) of 9-12 μm. The basecoat was dried for 10 min at room temperature, 30 min at 80 ° C. in a convection oven and stored for 3 h at room temperature.

Finally, the solvent-based clearcoat was prepared as described above and immediately after mixing the base paint and hardener with a Satajet HVLP gravity gun, 1.2 mm, air pressure 2.1 bar, applied in 1 cross-pass to achieve a layer thickness (dry) of 25-32 μm produce. The clearcoat was dried for 10 minutes at room temperature and 45 minutes at 80 ° C. in a circulating air oven.

Visual assessment of the entire painted structure:

The visual assessment of the surface of the overall structure of substrate layer, top layer and lacquer was carried out after aging of the coated panels for at least 16 h at 60 ° C. in a forced-air oven followed by 8 h storage at room temperature. The results of the visual assessment are shown in Table 5.

The grade “1” was awarded if the coated substrate layer-top layer laminate was free of bubbles, collapses, blisters or cracks and if fibers from the substrate underneath the film were at most minimally visible on the surface.

The grade “2” was awarded if the coated substrate layer-top layer laminate was free of bubbles, sink marks, blisters or cracks, but if fibers from the substrate underneath the film were visible on the surface.

The grade “3” was awarded if the if the coated substrate layer-top layer laminates had bubbles, sink marks, blisters and / or cracks.

It was found that grades 1 and 2 could only be achieved with a certain concentration of the polyester components B1 to B4 in the top layer, whereas always without admixing a polyester component (when using the pure component A) Bubbles, sink marks, blisters and / or cracks occurred after painting (Example 17, grade 3).

When using PBT (B1) and PET (B2) as polyester components, good painting results were achieved from a content of 18% by weight based on the total weight of the composition of the top layer (Examples 2-4 and 6-8). When using PBT, the visual impression of the surfaces was also greatly improved from 36% by weight, in that fibers from the substrate underneath the film were less visible on the coated surface (Example 3), while this effect was achieved when using PET was only noticeable from a higher concentration in the top layer (Example 8).

When using B3 as the polyester component, good painting results were achieved from a content of 9% by weight based on the total weight of the composition of the top layer (Examples 9-12), the visual impression of the surfaces being greatly improved from 36% by weight , since fibers from the substrate underneath the film were less evident on the coated surface (Examples 11 and 12).

When using PEN (B4) as the polyester component, good painting results were only achieved from a higher content of 36% by weight, based on the total weight of the composition of the top layer (Examples 15 and 16) The substrate lying on the film appeared on the coated surface and the grade 1 could not be achieved accordingly.

- 30 -

Table 4 (E: example according to the invention; V: comparative example; all data in% by weight, based on the total weight of the composition):

Table 5: (E: example according to the invention; C: comparative example)

Claims

Patent claims:

1. Layer composite comprising a substrate layer S and a cover layer D at least partially connected to the substrate layer S, the material of the substrate layer S comprising a first thermoplastic polymer and the material of the cover layer D also comprising the first thermoplastic polymer, characterized in that the first thermoplastic polymer is an aromatic polycarbonate and in the material of the outer layer D the first thermoplastic polymer is present as a blend with a polyester component P, i) the proportion of this polyester component P> 2% by weight, preferably> 5

% By weight, particularly preferably> 8% by weight, based on the

% By weight, particularly preferably> 17% by weight, based on the

% By weight, particularly preferably> 35% by weight, based on the

% By weight, particularly preferably> 8% by weight, based on the

2. Layer composite according to claim 1, wherein on the side of the cover layer D facing away from the substrate layer S there is also a lacquer layer L which is at least partially connected to the cover layer D.

3. Layer composite according to claim 1 or 2, wherein the substrate layer S further comprises reinforcing fibers.

4. Layer composite according to claim 3, wherein in the substrate layer S there are a plurality of plies of unidirectionally oriented continuous fibers and the continuous fibers of a layer do not have the same orientation as continuous fibers of immediately adjacent layers.

5. Layer composite according to one of claims 1 to 4, wherein the first thermoplastic polymer is the homopolycarbonate based on bisphenol A, the homopolycarbonate based on 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane Copolycarbonate based on the monomers bisphenol A and l, l-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane or a mixture of at least two of the aforementioned polymers.

7. Layer composite according to one of claims 1 to 6, wherein the material of the cover layer D furthermore contains an impact modifier.

8. Layer composite according to one of claims 1 to 7, wherein the cover layer D has a thickness <500 μm.

9. Layer composite according to one of claims 2 to 8, wherein the lacquer layer L comprises at least one primer layer G, at least one basecoat layer B and at least one clearcoat layer K.

10. Layer composite according to claim 9, wherein at least one of the layers comprised by the lacquer layer L is water-based.

11. A method for producing a layer composite, comprising the step:

I) connecting a substrate layer S to a cover layer D, the material of the substrate layer S comprising a first thermoplastic polymer and the material of the cover layer D also comprising the first thermoplastic polymer, characterized in that the first thermoplastic polymer is an aromatic polycarbonate and in which Material of the cover layer D, the first thermoplastic polymer is present as a blend with a polyester component P, wherein i) the proportion of this polyester component P> 2% by weight, preferably> 5

% By weight, particularly preferably> 8% by weight, based on the

% By weight, particularly preferably> 17% by weight, based on the

% By weight, particularly preferably> 35% by weight, based on the

% By weight, particularly preferably> 8% by weight, based on the

12. The method according to claim 11, further comprising the step: II) applying at least one lacquer layer L to the side of the cover layer D facing away from the substrate layer S in the layer composite obtained after step I).

13. The method according to claim 11 or 12, wherein the substrate layer S further comprises reinforcing fibers.

14. The method according to any one of claims 12 or 13, wherein the lacquer layer L has at least one primer layer G, at least one basecoat layer B and at least one

Comprises clear lacquer layer K and where optionally at least one of the layers comprised by the lacquer layer L is water-based.

15. Automobile add-on parts, obtainable using a layer composite according to one of claims 1 to 9.