Methanolysis of a multi-layer body comprising polycarbonate and a coating comprising urethane bonds

Abstract

The present invention relates to a process for the recovery of a dihydroxy compound and optionally a vinyl(co)polymer and / or rubber-modified graft polymer from a multi-layer body comprising polycarbonate as a substrate layer and a coating layer comprising urethane bonds by methanolysis using a specific amount of a catalyst. Moreover, the present invention relates to the production of a polymer by polymerizing the dihydroxy compound recovered by the inventive process and the production of a polymer blend by blending the vinyl(co)polymer and / or rubber-modified graft polymer recovered by the inventive process with a further polymer.

Description

[0001] 2025PF30013-Foreign Countries

[0002] - 1 - METHANOLYSIS OF A MULTI-LAYER BODY COMPRISING POLYCARBONATE AND A COATING COMPRISING URETHANE BONDS

[0003] The present invention relates to a process for the recovery of a dihydroxy compound and optionally a vinyl(co)polymer and / or rubber-modified graft polymer from a multi-layer body comprising polycarbonate as a substrate layer and a coating layer comprising urethane bonds by methanolysis using a specific amount of a catalyst. Moreover, the present invention relates to the production of a polymer by polymerizing the dihydroxy compound recovered by the inventive process and the production of a polymer blend by blending the vinyl(co)polymer and / or rubber-modified graft polymer recovered by the inventive process with a further polymer.

[0004] Polycarbonates (PC) are applied diversly in industry and everyday life. They are known for their good property profile in terms of mechanical and optical properties, temperature resistance, and weathering stability. Due to this property profile, polycarbonates have long been used in a wide variety of indoor and outdoor applications, for example for the automotive sector, for rail vehicles, for the construction sector, for the electrical / electronics / IT sector, for battery housings for household appliances, for the lighting sector or for the medical technology sector. The property profile of polycarbonate may further be adjusted to the demands of the respective use via the selection of additional polymeric components added to the polycarbonate and the ranges of amounts in which these components are used in the compositions.

[0005] To increase notch resistance, in particular at low temperatures, blending partners having elastomeric properties are added to the polycarbonate as impact modifiers. The impact modifiers in turn may differ in the chemical composition of the elastic component or else the morphology thereof. An important class of impact modifiers are rubber-modified graft polymers. They can be blended with polycarbonate in a compounding process and a two-phase morphology is created. In most cases the phase morphology of these polycarbonate blends is such that polycarbonate forms the matrix phase and the rubber-modified graft polymer forms domains within the matrix phase.

[0006] Typically, such rubber-modified graft polymers can additionally comprise at least one vinyl(co)polymer which is not bound to the rubber. Amongst those, styrene-acrylonitrile copolymers (SAN) combined with polybutadiene-based rubber particles, commonly known as acrylonitrile-butadiene-styrene (ABS), is the most prominent component. It is used on a large scale as blending partner with incorporated impact modifier for polycarbonate compositions. In this combination the rubber particles improve notched impact resistance and further mechanical properties, while SAN facilitates the melt flowability of the resulting blend with polycarbonate and hence facilitates processing to give molded articles.2025PF30013-Foreign Countries

[0007] - 2 - Especially in the automobile industry those polycarbonate and respective blends comprising polycarbonate and at least one blending partner are coated in order to increase the durability of those articles. The coating is usually applied in multiple layers. In multi-layer systems of this kind for automobile chassis, a primer surfacer is first applied, then a basecoat layer followed by a crosslinked clearcoat layer.

[0008] As a result of the range of application possibilities due to a versatile and adjustable property profile, and the associated economic success, large quantities of waste comprising at least polycarbonate and a coating layer are generated. Such waste which may comprise additional blend partners must be put to meaningful use. The technically simplest type of use is incineration, utilizing the released combustion heat for other processes, such as industrial manufacturing processes. However, this method does not allow for the closure of raw material cycles. Chemical recycling which refers to the cleavage of the polycarbonate bonds for recovering the raw materials underlying the polycarbonate production are also known. The raw materials to be recovered usually include bisphenols, especially bisphenol A. Depending on the type of chemical recycling, a carbonate-containing compound such as diphenyl carbonate or dimethyl carbonate, or even CO2, can also be obtained. In case of compositions comprising polycarbonate and at least one polymeric blend partner such as for example ABS or PMMA this polymeric blend partner would be also a valuable raw material and thus, it would be desirable to recycle it.

[0009] However, multi-layer bodies comprising a substrate layer and a coating layer in particular are challenging in the context of recycling due to their diverse multi-component structure. The chemical nature of the substrate layer and the coating layer substantially differs. In order to get high quality raw materials by chemical recycling of such multi-layer bodies, the coating layers are typically removed from the substrate layers. Still such a delamination is also not easy as the multi-layer bodies are designed to have a high adhesion between the different layers in order to have long lasting properties even under harsh outdoor conditions.

[0010] DE 10 2022 133 789 A1 discloses a method recycling a multi-layer body, wherein the coating layer is hydrolytically delaminated from the substrate layer.

[0011] JP 4575046 B2 discloses a method for obtaining an aromatic dihydroxy compound metal salt aqueous solution from a laminate having a film of a resin other than an aromatic polycarbonate, e.g. melamine, acrylic, methacrylic or organopolysiloxane resins, laminated on an aromatic polycarbonate molded product. The method comprises the steps of dissolving the laminate in chlorinated organic solvent and filtering the undissolved material comprising the film material before decomposing the aromatic polycarbonate dissolved in the chlorinated organic solvent in the presence of sodium hydroxide aqueous2025PF30013-Foreign Countries

[0012] - 3 -solution into an aromatic dihydroxy compound. Accordingly, the coating layer is removed before the chemical recycling process is started. Such a process has the draw back that an additional and complicated step of removal of the coating layer from the substrate layer is required. Moreover, this specific process involves a high amount of chlorinated solvents. Such solvents require additional effort of handling and need to be removed afterwards.

[0013] The mentioned documents disclose methods of removal of the coating layer from the substrate layer, both requiring a lot of effort.

[0014] Only few of the chemical recycling processes known in the literature are currently operated on an industrial scale. This is particularly true for the chemical recycling of compositions and articles (especially end of life articles) not solely comprising polycarbonate but also additional polymeric components as blend partners, additives or coatings. This is mainly due to the lack of process efficiency in terms of limited product yield, the high complexity of processes and / or the limited quality of the reaction products obtained.

[0015] Based on this prior art, it was an object of the present invention to improve at least one known disadvantage. Especially, there was need to develop an efficient and scalable recycling process, preferably a methanolysis for multi-layer bodies comprising a substrate layer comprising polycarbonate and a coating layer comprising urethane bonds. Preferably, it was an object of the present invention to provide a process, preferably a methanolysis which recovers a dihydroxy compound at a high yield and / or good quality and optionally also a vinyl(co)polymer and / or a rubber-modified graft polymer from such multi-layer body. More preferably, this process, preferably the methanolysis should be economically and / or ecologically efficient. In particular this means that the process, preferably the methanolysis should need as few steps as possible and still preferably as few resources (including energy and / or (raw) materials such as catalyst, reactants and / or solvents, e. g. methanol and / or dimethyl carbonate) as possible. This is preferably understood that the process should need as few additional resources as possible (e. g. solvents). In addition it was preferable to have process which avoids the use of halogenated solvents. Moreover, it was preferred to provide a process, preferably a methanolysis for depolymerizing such multi-layer bodies that allows for the efficient depolymerization of polycarbonate into its building blocks (e.g. dihydroxy compounds also referred to as monomers) leading to improved yield and / or purity of the dihydroxy compounds as well as the efficient separation and / or purification of the obtained products. This preferably includes the dihydroxy compounds and at least the coating layer, preferably in addition also all other products. Most preferably this includes the vinyl (co)polymer and / or a rubber-modified graft polymer optionally contained in the multi-layer body. This should increase the overall efficiency of the process, preferably methanolysis. Finally, it was an object of the present invention to provide a process, preferably a methanolysis which works at mild process conditions (e. g.2025PF30013-Foreign Countries

[0016] - 4 -low temperature) and still gives high yields, preferably in a short time. Preferably, at least two and most preferably all of the above-mentioned needs were an object of the present invention.

[0017] At least one of the above-mentioned objects, preferably all of these objects have been solved by the present invention.

[0018] Surprisingly, it was found that the use of the process of a methanolysis provides for effective means to solve at least one, preferably all of the above-mentioned objects. Especially, it was found that the use of the process of a methanolysis of a multi-layer body comprising a substrate layer comprising polycarbonate and a coating layer comprising urethane bonds leads to an efficient and scalable recycling process. In particular a dihydroxy compound was obtained at a high yield and / or good quality. At the same time the process is very efficient as the coating layer can be removed after the methanolysis reaction. This means that the coating layer comprising urethane bonds is present throughout the methanolysis reaction. It was found that the use of a specific amount of the catalyst for the methanolysis reaction does not degrade the coating layer, specifically the urethane bonds. If the concentration of the catalyst in the methanolysis reaction is too high, the coating layer at least partially degrades leading to at least oligomers derived from the coating layer in the reaction mixture. Those oligomers are not easy to remove from the dihydroxy compound as main target molecule. On the other hand if the amount of catalyst in the methanolysis reaction is too low, the methanolysis reaction is not fast enough so that no economically reasonable process is obtained. Using the inventive conditions the coating layer remains as a solid in the methanolysis reaction mixture. While the substrate layer degrades and thereby slowly dissolves / transfers into the liquid phase, the coating layer is still present as a solid. As such it can be easily separated after the methanolysis reaction from the target compounds, i. e. at least the dihydroxy compound and optionally the vinyl(co)polymer and / or rubber-modified graft polymer. In case the multilayer body comprises a vinyl(co)polymer and / or a rubber-modified graft polymer optionally this compound could be recycled, too. The inventive findings lead to an economically and / or ecologically efficient process. The specific ratios of the components are preferably chosen in a way so that as few resources (e. g. energy and / or (raw) materials such as catalyst, reactants and / or solvents, e. g. methanol and / or dimethyl carbonate) as possible are needed. Moreover, this also requires smaller vessels or provides the possibility of recycling larger quantities due to high concentrations (especially when compared to a reaction having the same reaction time).

[0019] According to the present invention the amount of the catalyst in the methanolysis reaction is chosen in a way as not to degrade the coating layer, but efficiently depolymerize the substrate layer. Preferably in addition to this, the ratios of the components in the reaction mixture of the methanolysis of a multi-layer body comprising a substrate layer comprising polycarbonate comprising a structural unit derived from a dihydroxy compound and optionally at least one vinyl(co)polymer and / or a rubber-modified graft2025PF30013-Foreign Countries

[0020] - 5 -polymer are chosen in a way so that the optionally present vinyl(co)polymer and / or rubber-modified graft polymer is completely in the liquid phase (at least at the end of the methanolysis reaction of inventive step (ii)). This results in a viscosity of the reaction product (comprising at least the dihydroxy compound and the solid coating layer and optionally the vinyl(co)polymer and / or rubber-modified graft polymer) which is easily processable. The preferred process parameters prevent the formation of a sticky vinyl(co)polymer / rubber-modified graft polymer residue and at the same time allow the efficient depolymerization of PC and recovery of its monomers. More surprisingly, it has been preferably found that in case a vinyl(co)polymer and / or a rubber-modified graft polymer is present the inventive process leads to an increase in the yield of the dihydroxy compound. This increase is preferably seen when compared to the process in which the at least one vinyl(co)polymer and / or a rubber-modified graft polymer is not in the liquid phase in the reaction medium (at the end of the methanolysis reaction). Although for both processes the depolymerization of the PC is assumed to be completed, the yield of the dihydroxy compound is higher for the inventive process. This is especially true when comparing the same effort of washing (e.g. number of washing steps). It was found that the dihydroxy compound sticks to the at least one vinyl (co)polymer and / or a rubber-modified graft polymer (if present). Even when washing this dihydroxy compound cannot be easily removed from the at least one vinyl(co)polymer and / or a rubber-modified graft polymer. This means that a high number of washing steps would be required in order to increase the overall yield of the dihydroxy compound to result in an economically reasonable process. However, when using the inventive process the dihydroxy compound can be recovered (e.g. washed) from the at least one vinyl (co)polymer and / or a rubber-modified graft polymer more easily. This means that less washing steps are needed to get an economically reasonable process. This is especially true when compared to a process where the at least one vinyl(co)polymer and / or a rubber-modified graft polymer is not completely in the liquid phase at the end of the methanolysis reaction. Moreover, this means that a high yield of the dihydroxy compound can be obtained using less solvent for washing and / or less purification steps for recovering the dihydroxy compound resulting in less energy consumption are required. Moreover, the optionally resulting at least one vinyl(co)polymer and / or a rubber-modified graft polymer comprises less dihydroxy compounds especially when referring to the same effort of washing.

[0021] Moreover, the inventive process was found to be scalable and at the same time ecologically and / or economically effective. It was found that the coating layer can be easily removed from the methanolysis reaction mixture by means of solid liquid separation. Moreover, it was found that the optionally present at least one vinyl(co)polymer and / or a rubber-modified graft polymer can be precipitated in a way that it is filterable and can be easily removed from the (other) reaction products. This filtration needs low pressures and is very quick.2025PF30013-Foreign Countries

[0022] - 6 - Finally, the inventive process provides the possibility of using multi-layer bodies of varying particle size and composition and thus is flexible. This is due to the fact that the multi-layer bodies or the particles of the multi-layer body might be various mixtures of multi-layer bodies. This especially means that a broad range of end-of life material is processable according to the present invention still resulting in a very efficient, economically and ecologically reasonable process.

[0023] Accordingly, the present invention provides a process for the recovery of a dihydroxy compound from a multi-layer body comprising the steps of

[0024] (i) bringing into contact the multi-layer body, methanol, at least one catalyst and optionally dimethyl carbonate to form a reaction mixture, wherein the multi-layer body comprises

[0025] (A) a substrate layer comprising polycarbonate comprising a structural unit derived from a dihydroxy compound and

[0026] (B) a coating layer comprising urethane bonds,

[0027] (ii) performing a methanolysis reaction of the reaction mixture of step (i) yielding at least the dihydroxy compound from the polycarbonate of substrate layer A),

[0028] characterized in that the amount of the at least one catalyst is in the range of 0.01 to 10 wt.-%, preferably 0.05 to 5 wt.-%, still preferably 0.1 to 1 wt.-% and most preferably 0.2 to 0.5 wt.-% with respect to the polycarbonate of substrate layer A).

[0029] Preferably, the inventive process is a process for the recovery of a dihydroxy compound and optionally a vinyl(co)polymer and / or a rubber-modified graft polymer. This means that the inventive process provides a dihydroxy compound as direct product of the process. Sometimes and preferably, the inventive process also provides a vinyl(co)polymer and / or a rubber-modified graft polymer as direct product of the process (in case the multi-layer body indeed comprises such a component). Most preferably, the inventive process is a process, wherein the process is for the recovery of (2) the vinyl(co)polymer and / or the rubber-modified graft polymer. This means that (2) is not optional, but two direct products (1) the dihydroxy compound and (2) a vinyl(co)polymer and / or rubber-modified graft polymer are obtained.

[0030] The inventive process provides a dihydroxy compound. Sometimes the dihydroxy compound can be referred to as a diol within the context of the present invention. Moreover, the inventive process provides a dihydroxy compound which can be also a mixture of at least two dihydroxy compounds. This means that the inventive process provides at least one dihydroxy compound. It is understood by the skilled person that in case the multi-layer body comprises at least one copolycarbonate (this means that at least two comonomers are used to obtain the copolycarbonate) more than one dihydroxy compound can be obtained. Preferably, in case the dihydroxy compound is a mixture of at least two dihydroxy compounds,2025PF30013-Foreign Countries

[0031] - 7 -one dihydroxy compound is present to at least 50 %, more preferably at least 60 %, still preferably at least 70 %, still preferably at least 80 %, still preferably at least 90 %, still preferably at least 95 % and most preferably at least 99 % with respect to all dihydroxy compounds.

[0032] The dihydroxy compound is obtained by the methanolysis of the component A) of the multi-layer body. The skilled person knows how dihydroxy compounds can be used in order to obtain a polycarbonate and thus, it is also known to him how a polycarbonate is “derived” from a dihydroxy compound. Typically, those compounds are linked with carbonate groups while each of the two hydrogens is removed and the remaining oxygen is part of the carbonate group. This carbonate group of the polycarbonate is cleaved once again in the methanolysis reaction so that in the end the dihydroxy compound is formed (once again). This dihydroxy compound can be referred to as building block or monomer of the polycarbonate. In this context the term “structural unit" is used according to the invention. It preferably refers to a structural unit derived from a monomer formed by polymerizing a monomer, or a structural unit in which a portion of the structural unit is converted to another structure by processing a polymer. Preferably, the structural unit of the polycarbonate is represented by the following description of the dihydroxy compound, wherein the two hydrogens are removed and which are linked to each other by a carbonate group (cf. above). Accordingly, the skilled person is capable of deriving a structural unit of the polycarbonate when seeing the dihydroxy compound. Moreover, it is understood by the skilled person that the hydroxy compound is organic.

[0033] Preferably, the dihydroxy compound comprises, more preferably is a compound selected from the group

[0034] consisting of formula (1) and (IV) to (X), wherein

[0035]

[0036] wherein each Z independently represents a single bond, -S(=O)2-, -C(=O)-, -O-, -S-, -S(=O)-, -CH(CN)-, linear or branched Ci-Ce-alkylene which optionally comprises at least one carbonyl-group, optionally comprises at least one halogen atom and / or optionally is interrupted by at least one heteroatom, C2-Cio-alkylidene which optionally comprises at least one carbon-carbon- double bond, optionally comprises at least one carbonyl-group and / or optionally comprises at least one halogen atom, Cs-Cn-cycloalkylene, wherein the cycloaliphatic group is fused to at least one further cycloaliphatic ring, C5-C 15 -cycloalkylidene wherein the cycloaliphatic group is optionally fused to at least one cycloaliphatic and / or at least one aromatic ring, C7-C2o-aralkylidene, C8-C20- aralkylene, C6-C12-arylene optionally being fused to further aromatic rings which optionally may2025PF30013-Foreign Countries

[0037] comprise at least one hetero atom, formula (Bl -A), formula (Bl-B), formula (Bl-C) or formula (Bl-

[0038]

[0039] (Bl-A) (Bl-B) (Bl-C) (Bl-D),

[0040] wherein in formulae (Bl -A), (Bl-B) and (Bl-C) each R’ independently represents a linear C1-C4- alkyl, branched C’s-C -alkyl. aralkyl or aryl and the “C*” indicates the quaternary carbon atom which is at the position indicated as “Z” in formula (1), and

[0041] wherein in formula (Bl-D) each R’ independently represents a linear Ci-C4-alkyl, branched C3-C4- alkyl, each R” independently represents a linear Ci-C4-alkylene, branched C3-C4-alkylene, each R”’ independently represents H or linear Ci-Cs-alkyl, s is 0 to 2 and each si independently is 0 or 1, and the “*” indicate the bonds which link “Z” to the aromatic rings in formula (1),

[0042] each R5and R6independently represents H, Ci -Cis-alkyl, Cs-Ce-cycloalkyl, C1-C5-alkenyl-, Ci-Cis- alkoxy, phenoxy, halogen atom, Ce-Cis-aryl or Cy-Cis-aralkyl, and

[0043] each of pl and ql is 1 to 4,

[0044]

[0045] (V), (VI),

[0046]

[0047] (VII), wherein in formula (VII) each Rxindependently represents linear or branched Ci-Ce-alkyl, C1-C12-aryl, C1-C8-aralkyl or a halogen atom and t is 0 to 4,2025PF30013-Foreign Countries

[0048]

[0049] (IX), wherein in formulae (VIII) and (IX) each Y1 independently represents oxygen, sulfur or N-Ry, wherein Ryis H or -CH3, each Y2 interpedently represents a single bond, oxygen, sulfur or N-Ryas defined above and in formula (VIII) each R’ independently represents a linear Ci-C4-alkyl, branched C3-C4 alkyl, aralkyl or aryl and s is 0 to 2 and

[0050]

[0051] Preferably, the dihydroxy compound is aromatic. More preferably, the aromatic dihydroxy compound is a bisphenol. Most preferably, the dihydroxy compound is a compound of formula (1).

[0052] Still preferably, the dihydroxy compound is a compound of formula (1), wherein each Z independently represents a single bond, -S(=O)2-, -C(=O)-, -O-, -S-, -S(=O)-, linear or branched Ci-Ce-alkylene, C2-Cio-alkylidene which optionally comprises at least one carbon-carbon-double bond, C5-C15-cycloalkylidene wherein the cycloaliphatic group is optionally fused to at least one cycloaliphatic and / or at least one aromatic ring, C7-C15-aralkylidene and the C8-C15-aralkylene of formula (B1-E)

[0053]

[0054] (Bl-E),

[0055] wherein in formula (Bl-E) each R’ independently represents a linear Ci-C4-alkyl, branched C3-C4 alkyl, each R” independently represents a linear Ci-C4-alkylene, branched C3-C4 alkyl, s is 0 to 2 and each si independently is 0 or 1, and the “*” indicate the bonds which link “Z” to the aromatic rings in formula (1),

[0056] formula (Bl -A), formula (Bl-B), formula (Bl-C),2025PF30013-Foreign Countries

[0057] - 10 -each R5and R6independently represents H, C1-C18-alkyl, C5-C6-cycloalkyl, C1-C18-alkoxy, phenoxy, C6-C18-aryl or C7-C18-aralkyl and

[0058] each of pl and ql is 1 to 4.

[0059] More preferably, the dihydroxy compound comprises at least one compound of formula (1), wherein each Z independently represents a single bond, C2-Ce-alkylidene, C5-C12-cycloalkylidene wherein the cycloaliphatic group is optionally fused to at least one aromatic ring,

[0060] formula (Bl -A), formula (Bl-B), formula (Bl-C),

[0061] each R5and R6independently represents H, C1-C3-alkyl, C1-C18-alkoxy,

[0062] each of pl and ql is 1 to 4.

[0063] Still more preferably, the dihydroxy compound is a compound of formulae (la) or (lb)

[0064]

[0065] (la) (lb)

[0066] Most preferably, the dihydroxy compound is a compound of formula (la).

[0067] Preferably, in case the dihydroxy compound is a mixture, it is a mixture of at least two compounds of formula (1). In this case it is preferred that at least one compound of formula (1) is present to at least 20 wt.-%, more preferably at least 25 wt.-% and most preferably at least 50 wt.-% with respect to the weight of all compounds of formula (1).

[0068] It is also possible that the dihydroxy compound is a compound of formula (1), preferably of formula (la), in mixture with at least one dihydroxy compound of formula (1c), wherein

[0069] 04

[0070]

[0071] (lc),2025PF30013-Foreign Countries

[0072] - 11 -in which

[0073] R5represents hydrogen or Ci to C4 alkyl, Ci to C4 alkoxy, preferably hydrogen or methyl or methoxy, particularly preferably hydrogen,

[0074] R6, R7, R8and R9mutually independently represents Ce to C12 aryl or Ci to C4 alkyl, preferably phenyl or methyl, in particular for methyl,

[0075] Y represents a single bond, -SO2-, -S-, -CO-, -O-, Ci to Ce alkylene, C2 to C5 alkylidene, Ce to C12 arylene, which optionally can be condensed to at least one further aromatic ring, which further aromatic ring can comprise at least one hetero atom, or a C5 to Ce cycloalkylidene residue, which can be singly or multiply substituted with Ci to C4 alkyl, preferably a single bond, -O-, isopropylidene or a C5 to Ce cycloalkylidene residue, which can be singly or multiply substituted with Ci to C4 alkyl, and in particular isopropylidene,

[0076] V represents oxygen, C2 to Ce alkylene or C3 to Ce alkylidene, preferably oxygen or C3 alkylene, p, q and r mutually independently each stand 0 or 1,

[0077] with the provisio that if q = 0, W represents a single bond, if q = 1 and r = 0, W represents oxygen, C2 to Ce alkylene or C3 to Ce alkylidene, preferably oxygen or C3 alkylene,

[0078] if q = 1 and r = 1, W and V each independently represent C2 to Ce alkylene or C3 to Ce alkylidene, preferably C3 alkylene,

[0079] Z represents Ci to Ce alkylene, preferably C2 alkylene,

[0080] o represents an average number of repeating units from 10 to 500, preferably 10 to 100 and m represents an average number of repeating units from 1 to 10, preferably 1 to 6, particularly preferably 1.5 to 5.

[0081] Most preferably, the dihydroxy compound is a mixture of at least 20 wt.-%, more preferably at least 25 wt.-% and most preferably at least 50 wt.-% of a compound of formula (la) and another compound of formula (1) being different from formula (la), wherein the wt.-% refer to the weight of all dihydroxy compounds which are recovered by the inventive process. It is obvious to the skilled person that in the case where the dihydroxy compound is a mixture of at least two compounds, those compounds could or need to be separated from each other to obtain a respective pure dihydroxy compound.

[0082] “Alkyl” in the context of the present invention, for example and if not mentioned differently, refers to an alkane structure of which one hydrogen atom is removed. The “alkyl” of the present invention which can be linear or branched is saturated and therefore, it comprises only single bonds between adjacent carbon atoms. Preferably, alkyl groups according to the present invention comprise methyl, ethyl, n-propyl, isopropyl, w-butyl. sec-butyl. tert-butyl, w-pcntyl. 1 -methylbutyl, 2-methylbutyl, 3 -methylbutyl,2025PF30013-Foreign Countries

[0083] - 12 -neopentyl, 1 -ethylpropyl, w-hexyl, 1,1 -dimethylpropyl, 1,2-dimethylpropyl, 1,2-dimethylpropyl, 1-methylpentyl, 2-methylpentyl, 3 -methylpentyl, 4-methylpentyl, 1,1 -dimethylbutyl, 1,2-dimethylbutyl, 1.3-dimethylbutyl, 2,2-dimethylbutyl, 2,3 -dimethylbutyl, 3, 3 -dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl, 1,1,2-trimethylpropyl, 1,2,2-trimethylpropyl, 1 -ethyl- 1 -methylpropyl, 1 -ethyl -2 -methylpropyl, 1 -ethyl -2 -methylpropyl and the like. These structures can be limited in choice, in case the invention defines the carbon atoms of an alkyl group in a different manner.

[0084] “Alkylene” in the context of the present invention, for example and if not mentioned differently, refers to a bridging alkane structure of which two hydrogen atoms from different carbon atoms are removed. In this context the two carbon atoms of which the two hydrogens atoms are removed can be removed from any carbon atom which is present in the alkane structure. This means that the two carbon atoms can, but not necessarily must be, adjacent to each other. An alkylene structure can be linear or branched and is saturated. In case the alkylene group comprises only one carbon atom, the alkylene group is a methylene group (-CH2-) which is connected to the rest of the molecule by two single bonds. Preferably, alkylene groups according to the present invention comprise methylene, ethylene, w-propylcnc. isopropylene, w-butylcnc..scc-butylcnc. tert-butylene, w-pcntylcnc. 1 -methylbutylene, 2-methylbutylene, 3 -methylbutylene, neopentylene, 1 -ethylpropylene, w-hcxylcnc. 1,1-dimethylpropylene, 1,2-dimethylpropylene, 1,2-dimethylpropylene, 1 -methylpentylene, 2-methylpentylene, 3-methylpentylne, 4-methylpentylene, 1,1 -dimethylbutylene, 1,2-dimethylbutylene, 1.3 -dimethylbutylene, 2,2-dimethylbutylene, 2,3 -dimethylbutylene, 3, 3 -dimethylbutylene, 1-ethylbutylene, 2-ethylbutylene, 1,1,2-trimethylpropylene, 1,2,2-trimethylpropylene, 1 -ethyl- 1-methylpropylene, 1 -ethyl -2 -methylpropylene, 1 -ethyl -2-methylpropylene and the like. These structures can be limited in choice, in case the invention defines the carbon atoms of an alkylene group in a different manner. Moreover, the alkylene group according to the present invention optionally comprises at least one carbonyl-group, optionally comprises at least one halogen atom and / or optionally is interrupted by at least one heteroatom. Examples for such alkylene groups are -C(=O)-(CH2)4-C(=O)-, -C(=O)-(CH2)3-C(=O)-, -C(=O)-(CH2)2-C(=O)-, -C(CF3)2, -O-(CH2)4-O-, -O-(CH2)3-O-, -O-(CH2)2-O-or the like.

[0085] “Alkylidene” in the context of the present invention, for example and if not mentioned differently, refers to a bridging alkane structure of which two hydrogen atoms from the same carbon atom are removed. The alkylidene group optionally comprises at least one carbon-carbon-double bond, optionally comprises at least one carbonyl-group and / or optionally comprises at least one halogen atom. Preferably, alkylidene groups according to the present invention and / or in context with formula (3) comprise CH2=C*, C(CH3)2=C*, isopropylidene, w-propylidcnc. isoheptylidene, C*(CH3)(C(=O)CH3),2025PF30013-Foreign Countries

[0086] - 13 - C(Cl2)=C*, C(Br2)=C* or the like, wherein the “C*” indicates the carbon atom which is at the position indicated as “Z” in formula (1).

[0087] “Cycloalkylene” in the context of the present invention, for example and if not mentioned differently, refers to a bridging cycloalkane structure of which two hydrogen atoms from different carbon atoms in the ring are removed. In this context the two carbon atoms of which the two hydrogens atoms are removed can be removed from any carbon atom which is present in the cycloalkane structure. This means that the two carbon atoms can, but not necessarily must be, adjacent to each other. According to the present invention the cycloaliphatic group of the cycloalkylene group is fused to at least one further cycloaliphatic ring. Examples of such a cycloalkylene group is the adamantanylene (tricyclo [3.3.

[0088] 1.1 3,7 ] decanediyl).

[0089] “Cycloalkylidene” in the context of the present invention, for example and if not mentioned differently, refers to a bridging cycloalkane structure of which two hydrogen atoms from the same carbon atom in the ring are removed. The cycloaliphatic group of the cycloalkylidene group is optionally fused to at least cycloaliphatic and / or at least one aromatic ring. Examples of such cycloalkylidene groups are cyclopentylidene, cyclohexylidene, 3,3,5-trimethylcyclohexylidene, cyclodecylidene, cyclododecylidene, tetrahydrodicyclopentylidene, 9-fluorenylidene or the like.

[0090] “Aralkylidene” in the context of the present invention, for example and if not mentioned differently, refers in each case independently to a bridging straight-chain, cyclic, branched or unbranched alkyl structure of which two hydrogen atoms from the same carbon atom are removed and which is singly, multiply or polysubstituted by aryl radicals. In parallel, “aralkylene” refers in each case independently to a bridging straight-chain, cyclic, branched or unbranched alkyl structure of which two hydrogen atoms from the different carbon atoms are removed and which is singly, multiply or polysubstituted by aryl radicals. “Aryl” in the context of the present invention, for example and if not mentioned differently, is a carbocyclic aromatic radical. Examples of “aryl” are phenyl, o-. p-. m-tolyl. naphthyl, phenanthryl or anthracenyl. Examples of such aralkylidene groups especially in the context of formula (3) are phenyl-CH*, phenyl-C*(CH3), naphthyl-CH*, phenyl-C* -phenyl or the like, wherein the “C*” indicates the carbon atom which is at the position indicated as “Z” in formula (1). Examples of such aralkylene groups are m-diisopropylidcnc phenylene, -diisopropylidene phenylene.

[0091] “Alkoxy” in the context of the invention, for example and if not mentioned differently, refers to a linear, cyclic or branched alkyl group singularly bonded to oxygen (-OR). Preferably, alkoxy groups according to the present invention have 1 to 6 carbon atoms and, thus, comprise methoxy, ethoxy, w-propoxy. isopropoxy, w-butoxy. scc-butoxy. tert-butoxy, w-pcntoxy. 1 -methylbutoxy, 2-methylbutoxy, 3-methylbutoxy, neopentoxy, 1 -ethylpropoxy, cyclohexoxy, cyclopentoxy, w-hcxoxy. 1,1-2025PF30013-Foreign Countries

[0092] - 14 -dimethylpropoxy, 1,2-dimethylpropoxy, 1,2-dimethylpropoxy, 1 -methylpentoxy, 2-methylpentoxy, 3-methylpentoxy, 4-methylpentoxy, 1,1 -dimethylbutoxy, 1,2-dimethylbutoxy, 1,3 -dimethylbutoxy, 2,2-dimethylbutoxy, 2,3 -dimethylbutoxy, 3, 3 -dimethylbutoxy, 1 -ethylbutoxy, 2-ethylbutoxy, 1,1,2-trimethylpropoxy, 1,2,2-trimethylpropoxy, 1 -ethyl- 1 -methylpropoxy, 1 -ethyl -2 -methylpropoxy or 1-ethyl-2-methylpropoxy. These structures can be limited in choice, in case the invention defines the carbon atoms of an alkoxy group in a different manner.

[0093] A “halogen atom” in the context of the invention, if not mentioned differently, refers to fluorine (F), chlorine (Cl), bromine (Br), or iodine (I). Preferably, a halogen atom is F, Cl, Br or I, more preferably it is Cl or Br.

[0094] Based on the above-given definitions the skilled person knows how to understand further definitions which are not explicitly defined in the passage above.

[0095] Substrate layer A)

[0096] According to the present invention substrate layer A) comprises a polycarbonate comprising a structural unit derived from a dihydroxy compound. Sometimes substrate layer A) is also referred to as component A). In this case reference is made to the polycarbonate as component A) which is in substrate layer A). This does not exclude that substrate layer A) does not comprise more than component A), e. g. a blend of polycarbonate and a vinyl(co)polymer and / or a rubber-modified graft polymer, cf. below.

[0097] As already described above, the skilled person is capable of identifying the connection between the polycarbonate which is used as substrate layer A) and the dihydroxy compound as recovered according to the inventive process. In the context of the present invention the term "polycarbonate" refers to a polymer that contains multiple carbonate groups. These carbonate groups are incorporated into the polymer backbone. This means that a polycarbonate preferably has repeating units of the form...-(R-O-(C=O)-O)-...

[0098] According to the present invention in the process a multi-layer bodyis used which comprises a polycarbonate comprising a structural unit derived from a dihydroxy compound as component A) (e. g. HO-R-OH, wherein the R represents the R as given for the above-shown repeating units of the polycarbonate). This polycarbonate is degraded by the process of the present invention to give the dihydroxy compound. Accordingly, the skilled person can understand the structure of the polycarbonate based on the structure as given for the dihydroxy compound. As example, the skilled person knows the structure of bisphenol A based polycarbonate.2025PF30013-Foreign Countries

[0099] - 15 - This means that “polycarbonates” in the context of the present invention generally comprise other structures besides the carbonate base structures. It is also possible that they comprise even other structures besides the carbonate base structures and the structural units which are derived from the dihydroxy compound. For example, typically a polycarbonate comprises a chain terminator. Moreover, this can be especially true in case the multi-layer body which comprises component A) is post-industrial waste or post-consumer waste, also known as end-of-life (EoL) material. Those materials might have structures which can be called “defective structures” due to the lifecycle of the polycarbonate. However, such “defective structures” can also be present in the virgin polycarbonate. Their amount could be higher than the amount in virgin polycarbonate. Polycarbonate chains are known to degrade under harsh conditions and / or UV light leading to rearrangement structures etc. Those structures are known to the skilled person. The presence of such structures diverging from the pure base structure does not depart from the scope of the present invention. Especially when referring to such EoL materials the exact structure of the polycarbonate might be unknown. However, the skilled person is able to determine whether the polycarbonate is derived from a dihydroxy compound (and in most cases also which exact compound). This is especially true as most of those materials comprise polycarbonate derived from bisphenol A.

[0100] According to the present invention, when calculating the molar equivalents and / or the weight of the dihydroxy compound to be obtained (cf. preferred condition (c) described in more detail below), the exact structure and / or molecular weight of the polycarbonate in the substrate layer of the multi-layer body is preferably not considered. The chemical nature of the dihydroxy compound is determined. This can be done by methods known to the skilled person. Preferably, the chemical nature of the polycarbonate can be determined by IR-spectroscopy and / or NMR-spectroscopy. It is also possible to firstly depolymerize the polymer (e. g. by saponification as described below) and to conduct a gas chromatography. Those methods are known to the skilled person. For example, when using IR spectroscopy, a KBr pellet of the article can be analyzed and compared to a calibration. By this the polycarbonate content can be determined and the molar equivalents and / or amount of the dihydroxy compound could be calculated. For example, the amount can be calculated by using the formula:

[0101] mf'polycarbonate'),,.,, „, - molecular weigth of structural unit of PC * molecular weiqnt of monomer = m(monomerx

[0102] ),

[0103]

[0104] wherein m(polycarbonate) represents the mass of the polycarbonate, the molecular weight of the monomer is the structural unit of PC, wherein C=O is substracted and two Hs are added (resulting in two OH-groups and no carbonate groups) and the molecular weight of the structural unit of PC includes a carbonate group (and no OH-groups). By this it can be also determined whether the multi-layer body comprises urethane bonds and - if using a calibration - the amount of the coating which is present. It is2025PF30013-Foreign Countries

[0105] - 16 -also possible to determine the weight of the dihydroxy compound to be obtained by saponification of the substrate layer and thus, the polycarbonate. This leads to the full degradation of the polymer chain to its monomers. This method might be more appropriate in case the IR spectrum of the multi-layer body itself has significant overlaps of signals, e.g. with the urethane bonds of the coating layer and / or with any other component being present in the multi-layer body.

[0106] For example, the multi-layer body could be subjected to a total hydrolysis to form the corresponding degradation products. This may be accomplished for example as follows: The multi-layer body is hydrolyzed under reflux by means of sodium methoxide (for example in dichloromethane). The corresponding solution is acidified (for example by HC1) and concentrated to dryness. The drying residue is dissolved in acetonitrile and the dihydroxy compounds are determined for example by means of HPLC with UV detection.

[0107] The multi-layer body and the monomers are preferably analyzed by IR spectroscopy. Based on the results of such IR analysis, the weight of the dihydroxy compound can be calculated as follows molecular weight of monomer

[0108] - - - - - — - - - - - - * 100 = % monomer in PC

[0109]

[0110] molecular weigth of structural unit of PC

[0111] wherein the molecular weight of the monomer is the structural unit of PC, wherein C=O is substracted and two Hs are added (resulting in two OH-groups and no carbonate groups) and the molecular weight of the structural unit of PC includes a carbonate group (and no OH-groups). Knowing the amount of PC to be depolymerized multiplied with the % of monomer in PC results in the weight of the dihydroxy compound which is then used in preferred condition (c).

[0112] Using bisphenol A (BPA) as example, the weight of BPA which is theoretically obtained by the preferred inventive process assuming 100 % conversion is:

[0113] 228

[0114] - * 100 = 89.76 % BPA in PC

[0115] 254

[0116]

[0117] mol

[0118] When calculating the molar equivalent and / or the weight of the dihydroxy compound to be obtained (cf. preferred condition (c) described in more detail below), all of the other structures which might be present in the polycarbonate are ignored. This is especially true for the chain terminator and / or any structure formed by rearrangement reactions or side reactions. Polycarbonates according to component A) which are suitable according to the invention are known from the literature or can be produced by processes known from the literature (for production of polycarbonates see by way of example Schnell, " Chemistry and Physics of Polycarbonates", Interscience Publishers, 1964 and also DE-AS (German2025PF30013-Foreign Countries

[0119] - 17 - Published Specification) 1 495 626, DE-A 2232 877, DE-A 2 703 376, DE-A 2 714 544, DE-A 3 000 610, DE-A 3 832396).

[0120] Aromatic polycarbonates are produced by way of example by reaction of diphenols with carbonyl halides, preferably phosgene and / or with aromatic diacyl dihalides, preferably dihalides of benzenedicarboxylic acids, by the interfacial process, optionally using chain terminators, for example monophenols, and optionally using trifunctional or more than trifunctional branching agents, for example triphenols or tetraphenols. Production via a melt polymerization process by reaction of diphenols with, for example, diphenyl carbonate is likewise possible.

[0121] Preferably, the polycarbonate of component A) comprises at least one structural unit of formula (3) to (10)

[0122]

[0123] wherein each Z each R5R6and each of pl and ql have the meanings as given above for formula (1) and m2 represents the average number of repeating units,

[0124]

[0125] wherein in formula (4) to (6) m2 represents the average number of repeating units;

[0126]

[0127] wherein each Rxindependently represents linear or branched Ci-Ce-alkyl, Ci-Ci2-aryl, Ci-Cs-aralkyl or a halogen atom, t is 0 to 4 and m2 represents the average number of repeating units;2025PF30013-Foreign Countries

[0128] - 18 -

[0129]

[0130] wherein in formula (8) and (9) each Y1 independently represents oxygen, sulfur or N-Ry, wherein Ryis H or -CH3, each Y2 interpedently represents a single bond, oxygen, sulfur or N-Ryas defined above and m2 represents the average number of repeating units and in formula (8) each R’ independently represents a linear Ci-C4-alkyl, branched C3-C4 alkyl, aralkyl or aryl and s is 0 to 2;

[0131]

[0132] (10),

[0133] wherein m3 represents the average number of repeating units.

[0134] Moreover, all preferred meanings and combinations of preferred meanings with respect to above-given formula (1) apply. In accordance with the above-given meanings for formula (1), the polycarbonate of component A) most preferably comprises structural units represented by formula (2a) and / or (2b)

[0135]

[0136] (2a) (2b),

[0137] wherein m2 represents the average number of repeating units, preferably 6 to 60.

[0138] Moreover, the polycarbonate of component A) preferably comprises at least one structural unit of formula (3) above, most preferably of formula (2a), and a structure of formula (2c)

[0139]

[0140] in which2025PF30013-Foreign Countries

[0141] - 19 - R5represents hydrogen or Ci to C4 alkyl, Ci to C4 alkoxy, preferably hydrogen or methyl or methoxy, particularly preferably hydrogen,

[0142] R6, R7, R8and R9mutually independently represents Ce to C12 aryl or Ci to C4 alkyl, preferably phenyl or methyl, in particular for methyl,

[0143] Y represents a single bond, -SO2-, -S-, -CO-, -O-, Ci to Ce alkylene, C2 to C5 alkylidene, Ce to C12 arylene, which optionally can be condensed to at least one further aromatic ring, which further aromatic ring can comprise at least one hetero atom, or a C5 to Ce cycloalkylidene residue, which can be singly or multiply substituted with Ci to C4 alkyl, preferably a single bond, -O-, isopropylidene or a C5 to Ce cycloalkylidene residue, which can be singly or multiply substituted with Ci to C4 alkyl, and in particular isopropylidene,

[0144] V represents oxygen, C2 to Ce alkylene or C3 to Ce alkylidene, preferably oxygen or C3 alkylene, p, q and r mutually independently each stand 0 or 1,

[0145] with the provisio that if q = 0, W represents a single bond, if q = 1 and r = 0, W represents oxygen, C2 to Ce alkylene or C3 to Ce alkylidene, preferably oxygen or C3 alkylene,

[0146] if q = 1 and r = 1, W and V each independently represent C2 to Ce alkylene or C3 to Ce alkylidene, preferably C3 alkylene,

[0147] Z represents Ci to Ce alkylene, preferably C2 alkylene,

[0148] o represents an average number of repeating units from 10 to 500, preferably 10 to 100,

[0149] m represents an average number of repeating units from 1 to 10, preferably 1 to 6, particularly preferably 1.5 to 5 and “...” represents the sites at which the structure of formula (2c) is incorporated into the polycarbonate.

[0150] The term “average number of repeating units” is known by the skilled person. The skilled person knows how to determine this parameter. Typically, it is determined by using a GPC method. Formulae (2a) and / or (2b) recite “m2” as number of repeating units. Preferably, m2 is 6 to 60, more preferably it is 10 to 55, even more preferably it is 20 to 50, still more preferably it is 25 to 45 and most preferably it is 30 to 40. Preferably, it is determined using the GPC method as outlined in the context of the present invention. Accordingly, according to the present invention it is preferred that the polycarbonate of component A) has a weight average molecular weight of 15000 g / mol to 40000 g / mol, more preferably 16000 g / mol to 34000 g / mol, still more preferably 17000 g / mol to 33000 g / mol and most preferably 19000 g / mol to 32000 g / mol as determined via size exclusion chromatography. Preferably, this size exclusion chromatography is calibrated using a bisphenol A polycarbonate and dichloromethane as eluent. Typically, linear polycarbonate (obtained from BPA and phosgene) having a known molecular weight2025PF30013-Foreign Countries

[0151] - 20 -distribution of PSS Polymer Standards Service GmbH, Deutschland can be used for the calibration. Most preferably, the calibration is performed according to method 2301-0257502-09D method (from 2009 in German) from the company Currenta GmbH & Co. OHG, Leverkusen. The eluent is dichloromethane. Preferably, a combination of columns based on crosslinked styrene divinylbenzene resins is used. Still preferably, the diameter of the analytical columns is 7,5 mm, length of 300 mm. The particle size of the column material is preferably 3 pm to 20 pm. The concentration of the solution is preferably 0.2 wt.-%. The flow rate is preferably 1.0 ml / min. The temperature of the solution is preferably 30 °C. Preferably, a UV- and / or Rl-detection is used.

[0152] According to the present invention component A) can comprise more than one polycarbonate. This means that component A) can be a mixture of at least two polycarbonates. However, especially when referring to EoL materials this cannot easily be determined. As outlined above, the knowledge of such a fact is not detrimental in order to carry out the process of the present invention.

[0153] Coating layer B)

[0154] According to the present invention the coating layer B) comprises urethane bonds. The skilled person knows that various coatings are available and commonly used which comprise urethane bonds. Moreover, it is known that in automobile application such a coating layer typically comprises more than one layer. On the other hand, in-mold-coating processes become more frequent resulting in coating layers comprising urethane bonds which typically comprise only one layer.

[0155] The most common exterior coating system for plastics in automotive applications typically comprises three distinct layers, each serving a specific purpose. The first layer, known as the primer surfacer, is applied directly to the prepared plastic surface. Its primary function is to provide excellent adhesion to the substrate, offer essential corrosion protection, and create a smooth surface for subsequent layers. The primer surfacer also helps to level minor imperfections in the substrate. In addition, its comparably high flexibility is the main reason the build-up of three layers can withstand stone chips.

[0156] The second layer typically is the basecoat, which is responsible for giving the vehicle its color and visual effects. This layer contains the pigments and special effect particles that determine the final appearance of the car.

[0157] The third and final layer typically is the clearcoat, which is a transparent coating applied over the basecoat. This clearcoat layer serves crucial protective functions while also enhancing the vehicle's aesthetic appeal. It shields the underlying layers from UV radiation, chemical exposure, and physical damage, while also providing gloss and durability to the finish. Together, these three layers - primer2025PF30013-Foreign Countries

[0158] - 21 -surfacer, base coat, and clear coat - form a comprehensive coating system that combines protection, color, and visual appeal for automotive exteriors.

[0159] Therefore, the coating layer B) comprising urethane bonds preferably is a multi-layer system comprising a primer surfacer, a basecoat layer and a clearcoat layer. This coating buildup is known to the skilled person as an automotive exterior coating buildup. Typically, such coating layers have thicknesses of 40 pm to 200 pm. Preferably, the primer surfacer has a thickness of 5 to 25 pm, the basecoat layer has a thickness of 5 to 25 pm and the clearcoat layer has a thickness of 30 to 150 pm.

[0160] The basecoat layer and clearcoat layer may be the same or different in terms of their chemical composition.

[0161] As alternative the coating layer B) comprising urethane bonds preferably is a coating layer obtained by an in-mold coating process. More preferably, it is obtained by curing of at least one polyisocyanate and at least one NCO-reactive compound. Both components are further described below. Typically, such coating layers have a thickness of 1 pm to 1500 pm, preferably of 500 pm to 1 mm.

[0162] In case the coating layer comprises a primer surfacer, it is preferred that the primer surfacer is obtained from a solventbome or aqueous primer system. More preferably, it is obtained from an aqueous two component primer system. Solventbome or aqueous primers for plastics are known. Typically, the primer surface system comprises a NCO-reactive compound. NCO-reactive compounds suitable for the primer surfacer are polyether polyols, polycarbonate polyols, polyester polyols, polyacrylate polyols, polyurethane polyols, polyacrylate polyols. These polyols are further described below with respect to the clearcoat layer. The NCO-reactive compound used in the primer surfacer is preferably one or more selected from polyester polyols, polyacrylate polyols and / or polyurethane polyols.

[0163] Preferably, the basecoat layer is a pigmented basecoat layer. Preferably, it is obtained from a one component aqueous system. Preferably, the basecoat layer of the invention is obtained using at least one NCO-reactive compound. Most preferably, the basecoat layer is obtained from a mixture of polyacrylic and polyurethane dispersions.

[0164] Compositions of, demands on and processing of basecoats are described, for example, in the specifications from the automobile companies or else, for example, in the article " Eine Frage der Einstellung” [A Question of Attitude], published in “Farbe und Lack 07 / 2003” (Vincentz-Verlag). Additionally in U. Poth, Automotive Coatings Formulation, Vincentz-Verlag 2008, ISBN 9783866309043 or U. Kuttler, Principles of Automotive OEM Coatings, Allnex Belgium S. A., downloaded on 11.03.2015 from http: / / www.farbeundlack.de / content / download / 263190 / 6322245 / file / 01_Kuttler.pdf. Formulations are2025PF30013-Foreign Countries

[0165] - 22 -also described in W. P. Öchsner, R. Nothhelfer-Richter, final report from the Forschungsinstitut für Pigmente und Lacke e. V., Stuttgart, DE, “Bestimmung der Haftfestigkeit zwischen Klarlack- und Wasserbasislackschicht und Untersuchung der Wechselwirkungen an der Grenzflache”, 10.26.2009. Preferably, the clearcoat layer is obtained by curing at least one polyisocyanate, at least one NCO-reactive compound in the presence of at least one catalyst.

[0166] In a preferred embodiment of the invention, the NCO-reactive compound present in the clearcoat layer is a polyhydroxyl compound. Preferably, the polyhydroxyl compound is selected from the group consisting of polyester polyols, polyurethane polyols, polysiloxane polyols, polycarbonate polyols, polyacrylate polyols and mixtures thereof.

[0167] An NCO-reactive compound is understood to mean a compound that can react with polyisocyanates to give polyisocyanate polyaddition compounds, especially polyurethanes. In the context of the invention, polyisocyanates are compounds having at least two isocyanate groups per molecule.

[0168] NCO-reactive compounds used may be any compounds known to those skilled in the art that have a mean OH or NH functionality of at least 1.5. These may, for example, be low molecular weight diols (e.g. ethane- 1,2-diol, propane-1,3- or -1,2-diol, butane- 1,4-diol), triols (e.g. glycerol, trimethylolpropane) and tetraols (e.g. pentaerythritol), short-chain polyamines, but also polyhydroxyl compounds such as polyether polyols, polyester polyols, polyurethane polyols, polysiloxane polyols, polycarbonate polyols, polyetherpolyamines, polybutadiene polyols, polyacrylate polyols and / or polymethacrylate polyols and copolymers thereof, called polyacrylate polyols hereinafter.

[0169] The polyhydroxyl compounds preferably have mass-average molecular weights Mw > 500 daltons, measured by means of gel permeation chromatography (GPC) against a polystyrene standard, more preferably between 800 and 100 000 daltons, especially between 1000 and 50 000 daltons.

[0170] The polyhydroxyl compounds preferably have an OH number of 30 to 400 mg KOH / g, especially between 100 and 300 KOH / g. The hydroxyl number (OH number) indicates how many mg of potassium hydroxide are equivalent to the amount of acetic acid bound by 1 g of substance in the acetylation. In the determination, the sample is boiled with acetic anhydride / pyridine, and the acid formed is titrated with potassium hydroxide solution (DIN 53240-2).

[0171] The glass transition temperatures, measured with the aid of DSC measurements according to DIN EN ISO 11357-2, of the polyhydroxyl compounds are preferably between -150 and 100°C, more preferably between -120°C and 80°C.2025PF30013-Foreign Countries

[0172] - 23 - Polyether polyols are obtainable in a manner known per se, by alkoxylation of suitable starter molecules under base catalysis or using double metal cyanide compounds (DMC compounds). Suitable starter molecules for the preparation of polyether polyols are, for example, simple low molecular weight polyols, water, organic polyamines having at least two N-H bonds, or any desired mixtures of such starter molecules.

[0173] Preferred starter molecules for preparation of polyether polyols by alkoxylation, especially by the DMC process, are especially simple polyols such as ethylene glycol, propylene 1,3-glycol and butane- 1,4-diol, hexane- 1,6-diol, neopentyl glycol, 2-ethylhexane-l,3-diol, glycerol, trimethylolpropane, pentaerythritol, and low molecular weight hydroxyl-containing esters of such polyols with dicarboxylic acids of the type specified hereinafter by way of example, or low molecular weight ethoxylation or propoxylation products of such simple polyols, or any desired mixtures of such modified or unmodified alcohols. Alkylene oxides suitable for the alkoxylation are especially ethylene oxide and / or propylene oxide, which can be used in the alkoxylation in any sequence or else in a mixture.

[0174] Suitable polyester polyols are described, for example, in EP-A-0 994 1 17 and EP-A-1 273 640. Polyester polyols can be prepared in a known manner by polycondensation of low molecular weight polycarboxylic acid derivatives, for example succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, tetrachlorophthalic anhydride, endomethylenetetrahydrophthalic anhydride, glutaric anhydride, maleic acid, maleic anhydride, fumaric acid, dimer fatty acid, trimer fatty acid, phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, citric acid or trimellitic acid, with low molecular weight polyols, for example ethylene glycol, diethylene glycol, neopentyl glycol, hexanediol, butanediol, propylene glycol, glycerol, trimethylolpropane, 1,4-hydroxymethylcyclohexane, 2-methylpropane-l,3-diol, butane- 1, 2, 4-triol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol, dibutylene glycol and polybutylene glycol, or by ring-opening polymerization of cyclic carboxylic esters such as a-caprolactone. In addition, it is also possible to poly condense hydroxycarboxylic acid derivatives, for example lactic acid, cinnamic acid or co-hydroxycaproic acid to give polyester polyols. However, it is also possible to use polyester polyols of oleochemical origin. Such polyester polyols can be prepared, for example, by full ring-opening of epoxidized triglycerides of an at least partly olefinically unsaturated fatty acid-containing fat mixture with one or more alcohols having 1 to 12 carbon atoms and by subsequent partial transesterification of the triglyceride derivatives to alkyl ester polyols having 1 to 12 carbon atoms in the alkyl radical.

[0175] Polyurethane polyols are preferably prepared by reaction of polyester prepolymers with suitable di- or polyisocyanates and are described, for example, in EP-A-1 273 640. Suitable polysiloxane polyols are described, for example, in WO-A-01 / 09260, and the polysiloxane polyols cited therein can preferably2025PF30013-Foreign Countries

[0176] - 24 -be used in combination with further polyhydroxyl compounds, especially those having higher glass transition temperatures.

[0177] The polyacrylate polyols that are very particularly preferred in accordance with the invention are generally copolymers and preferably have mass-average molar masses Mw between 1000 and 20 000 daltons, especially between 5000 and 10000 daltons, measured in each case by means of gel permeation chromatography (GPC) against a polystyrene standard. The glass transition temperature of the copolymers is generally between -100 and 100°C, especially between -50 and 80°C (measured by means of DSC measurements according to DIN EN ISO 11357-2).

[0178] The polyacrylate polyols preferably have an OH number of 60 to 250 mg KOH / g, especially between 70 and 200 KOH / g, and an acid number between 0 and 30 mg KOH / g. The acid number here indicates the number of mg of potassium hydroxide which is used for neutralization of 1 g of the respective compound (DIN EN ISO 2114).

[0179] The preparation of suitable polyacrylate polyols is known per se to those skilled in the art. They are obtained by free-radical polymerization of olefinically unsaturated monomers having hydroxyl groups or by free-radical copolymerization of olefinically unsaturated monomers having hydroxyl groups with optionally other olefinically unsaturated monomers, for example ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, butyl acrylate, butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, tert-butyl acrylate, tert-butyl methacrylate, amyl acrylate, amyl methacrylate, hexyl acrylate, hexyl methacrylate, ethylhexyl acrylate, ethylhexyl methacrylate, 3,3,5-trimethylhexyl acrylate, 3,3,5-trimethylhexyl methacrylate, stearyl acrylate, stearyl methacrylate, lauryl acrylate or lauryl methacrylate, cycloalkyl acrylates and / or cycloalkyl methacrylates, such as cyclopentyl acrylate, cyclopentyl methacrylate, isobornyl acrylate, isobornyl methacrylate or especially cyclohexyl acrylate and / or cyclohexyl methacrylate. Suitable olefinically unsaturated monomers having hydroxyl groups are especially 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 3 -hydroxypropyl acrylate, 3-hydroxypropyl methacrylate, 3 -hydroxybutyl acrylate, 3 -hydroxybutyl methacrylate and especially 4-hydroxybutyl acrylate and / or 4-hydroxybutyl methacrylate.

[0180] Further monomer units used for the polyacrylate polyols may be vinylaromatic hydrocarbons, such as vinyltoluene, alpha-methylstyrene or especially styrene, amides or nitriles of acrylic acid or methacrylic acid, vinyl esters or vinyl ethers, and in minor amounts especially acrylic acid and / or methacrylic acid. The term “polyisocyanate” as used here is a collective term for compounds containing two or more isocyanate groups (this is understood by the person skilled in the art to mean free isocyanate groups of the general structure -N=C=O) in the molecule. The simplest and most important representatives of2025PF30013-Foreign Countries

[0181] - 25 -these polyisocyanates are the diisocyanates. These have the general structure O=C=N-R-N=C=O where R typically represents aliphatic, alicyclic, araliphatic and / or aromatic radicals. According to the present invention at least one polyisocyanate can be used in order to obtain the clear coat layer.

[0182] Polyisocyanates are used to produce a multitude of polymers (e.g. polyurethanes, polyureas and polyisocyanurates) and low molecular weight compounds (for example those having uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and / or oxadiazinetrione structure).

[0183] In the present invention the term "polyisocyanates" refers to both monomeric and / or oligomeric polyisocyanates. Where reference is made in the present application to "oligomeric polyisocyanates", this means polyisocyanates formed from at least two monomeric diisocyanate molecules, i.e. compounds that constitute or contain a reaction product formed from at least two monomeric diisocyanate molecules.

[0184] The production of oligomeric polyisocyanates from monomeric diisocyanates is presently also referred to as modification of monomeric diisocyanates. This "modification" as used here means the reaction of monomeric diisocyanates, optionally with further isocyanate-reactive molecules, to afford oligomeric polyisocyanates having uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and / or oxadiazinetrione structure.

[0185] In principle, monomeric and oligomeric polyisocyanates are equally suitable for use in the reaction mixture according to the invention. Consequently, the polyisocyanate may consist essentially of monomeric polyisocyanates or essentially of oligomeric polyisocyanates. However, it may alternatively comprise oligomeric and monomeric polyisocyanates in any desired mixing ratios.

[0186] Irrespective of the underlying oligomeric structure (uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and / or oxadiazinetrione structure), an oligomeric polyisocyanate for preparing a clear coat layer preferably has a (mean) NCO functionality of 2.0 to 5.0, preferably of 2.3 to 4.5. Production processes for the oligomeric polyisocyanates having a uretdione, isocyanurate, allophanate, biuret, iminooxadiazinedione and / or oxadiazinetrione structure for use in the polyisocyanate are described, for example, in J. Prakt. Chem. 336 (1994) 185 - 200, in DE-A 1 670 666, DE-A 1 954 093, DE-A 2 414 413, DE-A 2 452 532, DE-A 2 641 380, DE-A 3 700 209, DE-A 3 900 053 and DE-A 3 928 503 or in EP-A 0 336205, EP-A 0339396 and EP-A 0798 299.

[0187] Preferred monomeric diisocyanates are those having a molecular weight in the range from 140 to 400 g / mol, having aliphatically, cycloaliphatically, araliphatically and / or aromatically bonded isocyanate groups, for example 1,4-diisocyanatobutane (BDI), 1,5-diisocyanatopentane (PDI), 1,6-diisocyanatohexane (HDI), 2-methyl-l,5-diisocyanatopentane, l,5-diisocyanato-2,2-dimethylpentane,2025PF30013-Foreign Countries

[0188] - 26 - 2.2.4- or 2,4,4-trimethyl-l,6-diisocyanatohexane, 1,10-diisocyanatodecane, 1,3- and 1,4-diisocyanatocyclohexane, l,4-diisocyanato-3,3,5-trimethylcyclohexane, l,3-diisocyanato-2-methylcyclohexane, l,3-diisocyanato-4-methylcyclohexane, l-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophorone diisocyanate; IPDI), 1-isocyanato-l -methyl -4(3)-isocyanatomethylcyclohexane, 2,4’- and 4,4'-diisocyanatodicyclohexylmethane (H12MDI), 1,3- and 1.4-bis(isocyanatomethyl)cyclohexane, bis(isocyanatomethyl)norbornane (NBDI), 4,4'-diisocyanato- 3,3'-dimethyldicyclohexylmethane, 4,4'-diisocyanato-3,3',5,5'-tetramethyldicyclohexylmethane, 4,4'-diisocyanato- 1, 1 '-bi(cyclohexyl), 4, 4'-diisocyanato-3,3 '-dimethyl- 1, 1 '-bi(cyclohexyl), 4,4'-diisocyanato-2,2',5,5'-tetramethyl-l, l'-bi(cyclohexyl), 1,8-diisocyanato-p-menthane, 1,3-diisocyanatoadamantane, l,3-dimethyl-5,7-diisocyanatoadamantane, 1,3- and 1,4-bis(isocyanatomethyl)benzene (xylylene diisocyanate; XDI), 1,3- and l,4-bis( 1-isocyanato-l -methylethyl)benzene (TMXDI) and bis(4-(l-isocyanato-l-methylethyl)phenyl) carbonate, 2,4- and 2,6-diisocyanatotoluene (TDI), 2,4'- and 4,4'-diisocyanatodiphenylmethane (MDI), 1,5-diisocyanatonaphthalene and any desired mixtures of such diisocyanates. Further diisocyanates that are likewise suitable may additionally be found for example in Justus Liebigs Annalen der Chemie, volume 562 (1949) pp. 75-136.

[0189] Most preferably, a polyisocyanate is used which consists of or contains one or more oligomeric polyisocyanates, where the one or more oligomeric polyisocyanates is / are formed on the basis of 1,4-diisocyanatobutane (BDI), 1,5-diisocyanatopentane (PDI), 1,6-diisocyanatohexane (HDI), isophorone diisocyanate (IPDI) or 4,4'-diisocyanatodicyclohexylmethane (H12MDI) or mixtures thereof.

[0190] Suitable catalysts for curing of the clearcoat layer are, for example, the catalysts commonly used in isocyanate chemistry, such as tertiary amines like triethylamine, pyridine, methylpyridine, benzyldimethylamine, N, N -endoethylenepiperazine, N -methylpiperidine, pentamethyldiethylenetriamine, N, N-dimethylaminocyclohexane, N, N'-dimethylpiperazine or metal salts such as iron(III) chloride, zinc chloride, zinc 2-ethylcaproate, tin(II) octanoate, tin(II) ethylcaproate, dibutyltin(IV) dilaurate, bismuth(III) 2-ethylhexanoate, bismuth(III) octanoate or molybdenum glycolate.2025PF30013-Foreign Countries

[0191] - 27 - Component C)

[0192] According to the present invention, preferably the multi-layer body additionally comprises at least one vinyl(co)polymer and / or a rubber-modified graft polymer as component C). According to the present invention the vinyl (co)polymer can be also referred to as “rubber-free vinyl(co)polymer”. This especially helps to distinguish the rubber-modified graft polymer and the vinyl(co)polymer which is rubber free. It is explained below where component C) is present in the multi-layer body with respect to layers A) and B).

[0193] Preferably, the rubber-modified graft polymer comprises

[0194] C.1 5 to 95% by weight, preferably 20 to 92% by weight, in particular 30 to 91% by weight, based on the graft polymer, of at least one vinyl monomer on

[0195] C.2 95 to 5% by weight, preferably 80 to 8% by weight, in particular 70 to 9% by weight, based on the graft polymer, of one or more rubber-elastic graft substrates having glass transition temperatures < -10°C, more preferably < -40°C, particularly preferably < -70°C, determined by dynamic scanning calorimetry (DSC) according to DIN EN 61006 in the version of 2004 at a heating rate of 10 K / min with determination of Tg as the midpoint temperature (tangent method).

[0196] The graft substrate C.2 preferably has a median particle size (D50) of 0.05 to 10.00 pm, preferably of 0.1 to 5.0 pm, and particularly preferably of 0.1 to 1.5 pm.

[0197] The median particle size D50 is the diameter with 50 % by weight of the particles above it and 50 % by weight below it. Unless expressly stated otherwise in the present invention it is determined for all components by means of ultracentrifuge measurement (e. g. W. Scholtan, H. Lange, Kolloid, Z. und Z. Polymere [Polymers] 250 (1972), 782-1796).

[0198] The monomers C.l are preferably mixtures of

[0199] C.1.1 65 to 85 % by weight, particularly preferably 70 to 80 % by weight, more preferably 74 to 78 % by weight, in each case based on the sum of C.1.1 and C.l.2, of vinylaromatics and / or ring-substituted vinylaromatics (such as styrene, a-methylstyrene, p-methylstyrene, p- chlorostyrene) and / or (Ci-C2o)-alkyl (meth)acrylates, preferably (Ci-Cs)-alkyl (meth)acrylates, such as methyl methacrylate, ethyl methacrylate, and

[0200] C.l.2 15 to 35 % by weight, particularly preferably 20 to 30 % by weight, more preferably 22 to 26 % by weight, in each case based on the sum of C.1.1 and C.l.2, of vinyl cyanides (unsaturated nitriles such as acrylonitrile and methacrylonitrile) and / or (Ci-C2o)-alkyl (meth)acrylates, preferably (Ci-Cs)-alkyl (meth)acrylates, such as methyl methacrylate, n-2025PF30013-Foreign Countries

[0201] - 28 - butyl acrylate, t-butyl acrylate, and / or derivates (such as anhydrides and imides) of unsaturated carboxylic acids, for example maleic anhydride.

[0202] Preferred monomers C.1.1 are selected from at least one of the monomers styrene, a -methylstyrene and methyl methacrylate; preferred monomers C.1.2 are selected from at least one of the monomers acrylonitrile, maleic anhydride and methyl methacrylate. Particularly preferred monomers are C.1.1 styrene and C.1.2 acrylonitrile. Alternatively preferred monomers are C.1.1 methyl methacrylate and C.1.2 methyl methacrylate.

[0203] Suitable graft substrates C.2 of the graft polymers include for example diene rubbers, EP(D)M rubbers, i.e. those based on ethylene / propylene and optionally diene, acrylate, polyurethane, silicone, chloroprene, ethylene / vinyl acetate and also acrylate-silicone composite rubbers.

[0204] Preferred graft substrates C.2 are diene rubbers, preferably comprising butadiene or copolymers of dienes, preferably comprising butadiene, and further copolymerizable vinyl monomers (e.g. according to C.1.1 and C.1.2) or mixtures of one or more of the above-mentioned components.

[0205] A particularly preferred graft substrate C.2 is pure polybutadiene rubber. In a further preferred embodiment C.2 is styrene-butadiene rubber, particularly preferably styrene-butadiene block copolymer rubber.

[0206] Alternatively preferred graft substrates C.2 are acrylate rubbers, preferably selected from polymers of alkyl acrylates, optionally with up to 40 % by weight, based on C.2, of other polymerizable, ethylenically unsaturated monomers. Preferred alkyl acrylates include Ci to Cs alkyl esters, especially methyl, ethyl, butyl, n-octyl and 2-ethylhexyl esters; halogenated alkyl esters, preferably halogenated Ci to Cs alkyl esters, such as chloroethyl acrylate, and mixtures of these monomers. Preferred ‘other’ polymerizable, ethylenically unsaturated monomers which, in addition to the alkyl acrylates, can optionally be used to produce the graft substrate B.2 are, for example, acrylonitrile, styrene, * -methyl styrene, acrylamides, vinyl Ci to Ce alkyl ether, methyl methacrylate, butadiene.

[0207] The gel fraction of the graft substrate C.2 is at least 30 % by weight, preferably at least 40 % by weight, in particular at least 60 % by weight, in each case based on B.2 and measured as insoluble fraction in toluene.

[0208] The gel content of the graft substrate C.2 / of the graft polymers in component C) is determined at 25 °C in a suitable solvent as content insoluble in these solvents (M. Hoffmann, H. Kromer, R. Kuhn, Polymeranalytik I und II, Georg Thieme-Verlag, Stuttgart 1977).

[0209] Most preferred as rubber-modified graft polymer is acrylonitrile-butadiene-styrene (ABS).2025PF30013-Foreign Countries

[0210] - 29 - The graft copolymers in component C) are produced by free-radical polymerization, for example by emulsion, suspension, solution or bulk polymerization. Mixtures of graft polymers produced in different processes may also be used as component B. The graft polymers in component B are preferably produced by emulsion or bulk polymerization.

[0211] Suitable graft polymers produced in the emulsion polymerization process are for example ABS polymers produced in the emulsion polymerization process by redox initiation with an initiator system composed of organic hydroperoxide and ascorbic acid according to US-P 4937285.

[0212] Further suitable graft polymers produced in the emulsion polymerization process are MBS modifiers having a core-shell structure.

[0213] Suitable polymers according to component C) prepared by bulk polymerization are described for example in DE-OS 2 035 390 (=US PS 3 644 574) or in DE-OS 2248 242 (=GB-PS 1 409275), or in Ullmanns, Enzyklopadie der Technischen Chemie, Vol. 19 (1980), p. 280 et seq.

[0214] The rubber-modified graft polymer may comprise free, i.e. not chemically bonded to the rubber substrate and not included in the rubber particles, vinyl(co)polymer. This vinyl(co)polymer can be also referred to as rubber-free vinyl(co)polymer (cf. above). This means that typically, when component C) comprises a rubber-modified graft polymer in addition it also comprises at least one (rubber-free) vinyl(co)polymer. This means component C) preferably is at least one vinyl(co)polymer and a rubber-modified graft polymer. The vinyl(co)polymer preferably comprises structural units derived from the vinyl monomers according to C.l above. Preferably, the vinyl(co)polymer comprises structural units derived from at least one vinyl monomer selected from the group consisting of vinylaromatics, ring-substituted vinylaromatics, (Cl-C8)-alkyl (meth)acrylates, vinyl cyanides and unsaturated carboxylic acids. More preferably, the vinyl(co)polymer comprises structural units derived from at least one vinyl monomer selected from the group consisting of vinylaromatics, (Cl-C8)-alkyl (meth)acrylates and vinyl cyanides. It is understood that also combinations of the mentioned vinyl monomers are encompassed. Such vinyl(co)polymer may be formed in the rubber-modified graft polymer during the polymerization of the graft polymers owing to the method of production (the grafting on the graft substrate is not necessarily complete) or may else be polymerized and admixed with the rubber-modified graft polymer separately. It is likewise possible for a portion of the free vinyl(co)polymer in the rubber-modified graft polymer to originate from the graft polymer itself owing to the method of production and for another portion to be polymerized and admixed with the rubber-modified graft polymer separately.

[0215] Preferably, this free vinyl(co)polymer has in the rubber-modified graft polymer a weight-average molecular weight Mwof 30 to 250 kg / mol, preferably of 70 to 200 kg / mol, in particular of 90 to2025PF30013-Foreign Countries

[0216] - 30 - 180 kg / mol (measured by gel permeation chromatography (GPC) in tetrahydrofuran against a polystyrene standard). Preferably and in particular preferably in the context of the given weight-average molecular weight above the vinyl (co)polymer is styrene acrylonitrile resin (also known as SAN). In the context of the present invention, the weight average molecular weight Mw of the free vinyl(co)polymer in the rubber-modified graft polymer is measured by gel permeation chromatography (GPC) in tetrahydrofuran against a polystyrene standard.

[0217] According to the present invention, component C) can be also at least one vinyl(co)polymer with or without the additional presence of a rubber-modified graft polymer. Thus, this vinyl(co)polymer is rubber-free. Therefore, according to the present invention the vinyl(co)polymer is sometimes also referred to as rubber-free vinyl(co)polymer. This especially serves to distinguish between the at least one vinyl(co)polymer and the rubber-modified graft polymer. A vinyl(co)polymer is understood to be rubber-free if it is neither formed during the polymerization of a rubber-modified graft polymer nor polymerized and then admixed with a rubber-modified graft polymer. This means that the vinyl(co)polymer is polymerized and may then be admixed with a polycarbonate comprising a structural unit derived from a dihydroxy compound and optionally one or more polymer additives or polymeric components, without any rubber-modified graft polymer being present in the composition. It is also possible that the separately polymerized vinyl(co)polymer may be admixed with a polycarbonate and optionally rubber-modified graft polymer. Preferably, component C) consists of at least one vinyl(co)polymer.

[0218] The rubber-free vinyl(co)polymer preferably comprises structural units derived from at least one vinyl monomer C.l as defined above. More preferably, the vinyl(co)polymer is styrene-acrylonitrile copolymer, polyalkyl (meth)acrylate or alkyl (meth)acrylate copolymer. Particularly preferably, the vinyl(co)polymer is styrene-acrylonitrile copolymer and / or poly(methyl methacrylate).

[0219] Here and elsewhere according to the invention, the term “(meth)acrylate” refers to acrylates or methacrylates.

[0220] The (rubber-free) styrene-acrylonitrile copolymer preferably has a weight-average molecular weight Mw of 30 to 250 kg / mol, preferably of 70 to 200 kg / mol, in particular of 90 to 180 kg / mol (measured by gel permeation chromatography (GPC) in tetrahydrofuran against a polystyrene standard).

[0221] It is understood that polyalkyl (meth)acrylate may be a polyalkyl (meth)acrylate or a mixture of different polyalkyl (meth)acrylates. The polyalkyl (meth)acrylate is preferably a linear polymer.

[0222] The polyalkyl (meth)acrylate preferably has a weight-average molecular weight Mwof 50,000 to 2,000,000 g / mol, preferably of 80,000 bis 300,000 g / mol, further preferably of 100,000 bis2025PF30013-Foreign Countries

[0223] - 31 - 200,000 g / mol (measured by gel permeation chromatography (GPC) in tetrahydrofuran under PMMA calibration).

[0224] The polyalkyl (meth)acrylate can also be a mixture of two or more polyalkyl (meth)acrylates, one of which can also be of low molecular weight. The mentioned weight-average molecular weight then refers accordingly to the total polyalkyl (meth)acrylate mixture. At least one of these can be low molecular weight and have a weight-average molecular weight of 1,000 to 70,000 g / mol, most preferably 5,000 to 60,000 g / mol. The low-molecular weight polyalkyl (meth)acrylate preferably has a proportion of 2 to 20 wt.%, in particular 5 to 10 wt.%, based on the total weight of the polyalkyl (meth)acrylate. This improves the processability with the polycarbonate. The previously stated weight-average molecular weight of 50,000 to 2,000,000 g / mol, preferably of 80,000 to 300,000 g / mol, further preferably 100,000 to 200,000 g / mol, refers to the total polyalkyl (meth)acrylate contained in the composition according to the invention.

[0225] The polyalkyl (meth)acrylate preferably comprises

[0226] a) 52.0 to 100.0 wt.% of alkyl methacrylate repeating units with 1 to 20, preferably 1 to 12, more preferably 1 to 8, particularly preferably 1 to 4, carbon atoms in the alkyl radical, in particular methyl methacrylate,

[0227] b) 0 to 48.0 wt.% of alkyl acrylate repeating units containing 1 to 20, preferably 1 to 12, more preferably 1 to 8, particularly preferably up to 4, carbon atoms in the alkyl radical, in particular methyl acrylate, and

[0228] c) 0 to 8.0wt.% of styrenic repeating units of the general formula (VII)

[0229]

[0230] where R1to R5independently of one another are hydrogen, halogen, C1- to C6-alkyl or C2- to C6-alkenyl and R6is hydrogen or C1- to C6-alkyl

[0231] where the amounts in wt.% of a, b and c add up to 100.0 wt.%, the total weight of the polyalkyl (meth)acrylate.2025PF30013-Foreign Countries

[0232] - 32 - Very preferably, the polyalkyl (meth)acrylate comprises at least 60.0 wt.%, even more preferably at least 75.0 wt.%, in particular at least 85.0 wt.% methyl methacrylate repeating units.

[0233] Most preferably, the polyalkyl (meth)acrylate comprises 90.0 to 99.0 wt.% of methyl methacrylate and 1.0 to 10.0 wt.% of methyl acrylate, in each case based on the total weight of the polyalkyl (meth)acrylate.

[0234] In the context of the present invention, the polyalkyl (meth)acrylate is particularly preferred to be poly(methyl methacrylate). Preferably, the polyalkyl (meth)acrylate has a weight average molecular weight of 55 000 g / mol to 85 000 g / mol, more preferably of 60 000 g / mol to 80000 g / mol (as determined via GPC in THF using a polystyrene calibration).

[0235] As described above with respect to layer A), in EoL materials the chemical nature and / or the amount of component C) might be unknown. In order to determine the amount of component C) in the multi-layer body, it is possible to depolymerize the multi-layer body (e. g. saponify it as described above) and to determine the amount of the residue. It is also possible to analyze this residue to determine the chemical nature of component C). As described below, all unknown components in the multi-layer body are attributed to component C) for the sake of calculating the preferred inventive conditions (a) to (c). Therefore, the determination of the chemical nature of those components is not required for carrying out the present invention.

[0236] Multi-layer body

[0237] According to the present invention a “multi-layer body” is used from which the dihydroxy compound and optionally the vinyl(co)polymer and / or a rubber-modified graft polymer is or are recovered. The multi-layer body comprises layers A) and B) as described above. If component C) is present, the multilayer body can comprise a blend of polycarbonate and component C) in the substrate layer A). However, it might be also possible that the multi-layer body comprises layer A) and component C) which are spatially separated, for example in two distinct layers, one layer A) comprising polycarbonate and one layer of component C). Moreover, the multi-layer body may comprise further components and / or layers in addition to layers A) and B). Therefore, the multi-layer body can comprise a composition comprising at least polycarbonate of layer A) and C). Finally, the multi-layer body may be a mixture of different multi-layer bodies which comprise layers A) and B) and optionally component C) (e. g. a shredded multi-layer body comprising layers A) and B) is mixed with a shredded multi-layer body comprising B) or a shredded multi-layer body comprising at least a layer of component B) and the same or a different layer B) to result in a mixed multi-layer body comprising layers A), B) and C)). This may be2025PF30013-Foreign Countries

[0238] - 33 -encompassed when using the expression “the multi-layer body comprises layer A) and B) and optionally component C)”

[0239] An “multi-layer body” according to the present invention preferably means a substrate layer A) produced by processing a thermoplastic composition comprising at least polycarbonate into a (shaped or molded) article and the subsequent coating of the substrate layer A) with the coating layer B). Processing methods are known to the skilled person and include any plasticization method commonly used for polycarbonate, e.g. granulation, injection molding, (co)extrusion, blow molding, thermoforming. As explained above, processes for coating such substrates are also known to the skilled person. The multilayer body can have many different shapes and sizes and most preferably is a mixture of different multilayer bodies, especially shredded particles of different multi-layer bodies.. Preferably, the multi-layer body originates from post-industrial waste or post-consumer waste. This means that preferably, it is an end-of-life (EoL) material.

[0240] According to the present invention sometimes the term “polycarbonate blend composition” or “polycarbonate composition” is used. This refers to a composition comprising at least the polycarbonate of substrate layer A) and optionally component B).

[0241] The multi-layer body according to the present invention comprises a substrate layer A) comprising polycarbonate comprising a structural unit derived from a dihydroxy compound and optionally C) at least one vinyl(co)polymer and / or a rubber-modified graft polymer. The polycarbonate preferably comprises structural units derived from the dihydroxy compound of formula (1), more preferably from the dihydroxy compound of formulae (la) or (lb), most preferably from the dihydroxy compound of formula (la).

[0242] Preferably and most preferably in this context, component C) comprises as vinyl(co)polymer styreneacrylonitrile copolymer, polyalkyl (meth)acrylate and / or alkyl (meth)acrylate copolymer and / or as rubber-modified graft polymer acrylonitrile-butadiene-styrene.

[0243] The substrate layer A) may optionally comprise one or more polymer additives or polymeric components D). Here, it is preferable that the composition forming the substrate layer A) and optionally C) comprise one or more polymer additives or polymeric components D). It is understood that in case the polymeric components D) are present, they are no polycarbonate, no vinyl(co)polymers and / or no rubber-modified graft polymers. Preferably, component D) is selected from the group consisting of flame retardants, antidrip agents, flame retardant synergists, smoke inhibitors, lubricants and demolding agents, nucleating agents, antistatic agents, conductivity additives, stabilizers (e.g. heat stabilizers, hydrolysis and heat aging stabilizers, UV stabilizers and also transesterification inhibitors), flow promoters, phase2025PF30013-Foreign Countries

[0244] - 34 -compatibilizers, further polymeric constituents other than components A) and D) (for example functional blend partners), fdlers and reinforcing agents, light diffusing agents, dyes and pigments. Preferably, component D) is selected from the group consisting of thermal stabilizers, antioxidants, UV absorbers, lubricants and mold release agents.

[0245] Preferably, in the context of the present invention component D), if present, is ignored when calculating preferred conditions (a) to (c). This preferably means that for the calculation of (a) to (c) it is assumed that the substrate layer A) consists of polycarbonate and optionally component C), whereas all unknown components are attributed to the amount of C), if present.

[0246] Preferably, the substrate layer A) consists of at least 75 wt.-%, more preferably at least 80 wt.-%, still preferably at least 85 wt.-%, still preferably at least 90 wt.-%, still preferably at least 95 wt.-% and most preferably at least 98 wt.-% of polycarbonate, optionally component C) and optionally D), based on the weight of the whole substrate layer.

[0247] In the context of the present invention, “multi-layer body” can mean a single multi-layer body or a mixture of multi-layer bodies. A mixture of multi-layer bodies may include multi-layer bodies of the same origin, e.g. type of application and / or type of material or material mixture, or multi-layer bodies of multiple different origins. Even if multi-layer bodies of the same origin are present, they may still differ in terms of material composition and / or quality. It is also possible that the multi-layer body is a mixture of a multi-layer body or bodies with other articles such as polycarbonate compositions optionally comprising component C) which are not coated.

[0248] It may be advantageous to reduce the particle size of the multi-layer body by processes known to the skilled person such as shredding, crushing, cutting or milling prior to (bringing the multi-layer body into contact with methanol, a catalyst and optionally dimethyl carbonate according to) step (i) of the process according to the present invention. A smaller particle size may increase the surface and also the depolymerization rate. Preferably, the average particle size of the multi-layer body is below 1 cm, more preferably below 0.5 cm. This particle size preferably refers to the largest dimension of the shredded multi-layer body. Within the context of the present invention all measures to reduce the size of the collected multi-layer bodies are preferably referred to as shredding and the multi-layer bodies obtained after shredding are referred to as shredded multi-layer bodies. Most preferably, inventive process step (i) comprises bringing into contact at least a shredded multi-layer body, methanol, a catalyst and optionally dimethyl carbonate to form a reaction mixture.2025PF30013-Foreign Countries

[0249] - 35 - Catalyst

[0250] The methanolysis reaction is carried out in the presence of a catalyst. This is understood as “at least one catalyst”. Thus, it is also feasible to employ mixtures of different catalysts.

[0251] According to the present invention, it was found that if the catalyst is used in an amount of 0.01 to 10 wt.-%, preferably 0.05 to 5 wt.-%, still preferably 0.1 to 1 wt.-% and most preferably 0.2 to 0.5 wt.-% with respect to the polycarbonate in substrate layer A), the methanolysis reaction of the substrate layer A) is successful while at the same time the coating layer B) is not essentially degraded. When using higher amounts of catalyst, the coating layer B) degrades, too. This leads to more effort in isolating the target compound of the dihydroxy compound as degradation products of the coating layer B) are present in the reaction mixture at the end of step (ii). According to the present invention coating layer B) is present at the end of step (ii) as solid. This renders the separation of the reaction mixture at the end of process step (ii) and the coating layer B) very easy and efficient. By this a dihydroxy compound of high purity and quality can be obtained with less effort. This is especially true in case the multi-layer body additionally comprises component C). Using the preferred inventive conditions (a) to (c), it can be ensured that also component C) is in the liquid phase at the end of process step (ii). Therefore, also a recycled component C) can be obtained easily, because the separation of the coating layer B) from this component C) (and the dihydroxy compound) is easy. Preferably, the at least one catalyst is a transesterification catalyst. Preferably, the catalyst is a base.

[0252] The catalyst is preferably selected from the group consisting of alkali metal or earth alkali metal hydroxides, alkali metal or earth alkali metal carbonates, alkali metal or earth alkali metal alkoxides, alkali metal or earth alkali metal oxides, alkylamines, and pyridine.

[0253] The alkali metal or earth alkali metal hydroxide is preferably selected from the group consisting of lithium hydroxide, sodium hydroxide, calcium hydroxide and potassium hydroxide.

[0254] The alkali metal or earth alkali metal carbonate is preferably selected from the group consisting of sodium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate and potassium carbonate. The alkali metal or earth alkali metal alkoxide is preferably selected from the group consisting of lithium methoxide, sodium methoxide, calcium methoxide and sodium ethoxide.

[0255] The alkali metal or earth alkali metal oxide is preferably selected from the group consisting of sodium oxide, lithium oxide, calcium oxide and potassium oxide. The catalyst is more preferably an alkali metal hydroxide. Even more preferably, the catalyst is sodium hydroxide. This catalyst was found to provide sufficiently high depolymerization rates while being economically affordable.2025PF30013-Foreign Countries

[0256] - 36 - The catalyst can be added as such or in solution. For example, sodium hydroxide can be added in water and / or methanol. Most preferably, the catalyst sodium hydroxide is added in water.

[0257] Process step (i)

[0258] According to the present invention in process step (i) at least a multi-layer body, methanol, a catalyst and optionally dimethyl carbonate are brought into contact to form a reaction mixture. The multi-layer body and the catalyst are described above.

[0259] According to the present invention, the term "bringing into contact" is used. This is intended to encompass both embodiments in which one component / mixture etc. is added to another component / mixture etc., as well as the reverse order. How such contact between components and / or mixtures is established is known to those skilled in the art. This can be achieved, for example, by adding a component and / or mixture, introducing a component and / or mixture and afterwards adding another component and / or mixture, mixing a component and / or mixture, dripping in a component and / or mixture, etc. It is apparent to those skilled in the art that the term "adding," as occasionally used in the invention, can be understood as synonymous with "bringing into contact." The “bringing into contact in step (i) is preferably carried out with introduction of mixing energy. This may be carried out by methods known to those skilled in the art. It is known that increasing surface renewal influences the rate of methanolysis.

[0260] According to the present invention it is preferred that at least 2 molar equivalents of methanol compared to 1 molar equivalent of the structural unit derived from the dihydroxy compound in the polycarbonate of the substrate layer A) are used. Methanol is required to perform a methanolysis reaction. It is highly preferred to use higher amounts than this amount of methanol in order for the reaction mixture to have a manageable viscosity. At the same time other solvents for polycarbonate might be also present in process steps (i) and (ii). By adding a solvent which is capable of dissolving polycarbonate the viscosity in the inventive process can be influenced. However, this additional solvent needs to be separated afterwards which causes additional efforts. Therefore, it is less preferred to use an additional solvent except dimethyl carbonate. As dimethyl carbonate is formed during the methanolysis reaction, it needs to be removed afterwards anyway and thus, does not add any additional component to the reaction system. Moreover, it is possible to use high excesses of methanol compared to the structural unit derived from the dihydroxy compound in the polycarbonate. This however, is economically and ecologically disadvantageous. The skilled person is capable of finding the optimum amount of methanol. Preferably, the amount of methanol is defined as described below by inventive conditions (a) to (c).2025PF30013-Foreign Countries

[0261] - 37 - Moreover, according to the present invention it may not be possible to clearly distinguish between process step (i) and (ii). The presence of the catalyst in process step (i) may immediately initiate the methanolysis reaction. However, this does not depart from the present invention. It is clear to the skilled person that most preferably, in case process step (i) and (ii) cannot be clearly distinguished the amounts of methanol, polycarbonate of substrate layer A), coating layer B) and the optionally present component C) and / or dimethyl carbonate in inventive step (i) are preferably chosen so that conditions (a) to (c) are preferably met at the end of step (ii). This means that “before step (ii)” preferably means in step (i).

[0262] Most preferably, in inventive step (i) at least a shredded multi-layer body, methanol, at least one catalyst and optionally dimethyl carbonate are brought into contact. The preferred amount of methanol which is used in inventive step (i) is determined by inventive conditions (b) and (c). Those are described below. Moreover, the expression that dimethyl carbonate is “optionally” brought into contact with the multilayer body, methanol and the catalyst is understood by the skilled person. Preferably, inventive conditions (a) and (c) determine whether dimethyl carbonate is present already in process step (i) or whether it is solely (and / or additionally) formed during the methanolysis reaction in step (ii). Without being bound to a theory it was found according to the present invention that the preferred inventive conditions (a) to (c) which are further described below guarantee that component C) is in a liquid / dissolved state at the end of process step (ii). Dimethyl carbonate is a solvent for component C). This means that according to the present invention the expression “component C) is dissolved” or “in a dissolved state” is used. However, depending on the chemical nature of component C), an emulsion can be formed optionally in the presence of a dissolved component C) (the latter can be the case if component C) comprises at least two components). This is the reason why sometimes it is described that component C) is “in the liquid state”. Preferably, this means that component C) is present in the mixture as obtained after step (ii) as an emulsion and / or in a dissolved state. The skilled person knows that an emulsion is a finely distributed mixture of two normally immiscible liquids without visible separation. Most preferably, the emulsion is stable. This preferably refers to a mixture of at least two immiscible liquids where one liquid is dispersed in the other in the form of fine droplets, and this dispersion remains uniform over time without phase separation. According to the present invention this is encompassed when referring to a “solvent”. Especially in case when component C) is a mixture of ABS and SAN, it was found that SAN seems to be at least partly dissolved after step (ii) and the ABS is present as emulsion.

[0263] As dimethyl carbonate is a solvent for component C) it has the ability to dissolve and / or form an emulsion with component C). The methanolysis reaction leads to the formation of dimethyl carbonate. Depending on the amount of component C) in the multi-layer body different amounts of dimethyl carbonate are needed to support the dissolution and / or formation of an emulsion of component C).2025PF30013-Foreign Countries

[0264] - 38 - Therefore, preferred conditions (a) to (c) are preferably and inventively defined in a way to reflect this connection of the presence of component C) and dimethyl carbonate. Further preferred connections and influences are described below when explaining conditions (a) to (c).

[0265] Preferably, in inventive step (i) no further solvent, especially no further solvent for component C) is present. More preferably, in inventive step (i) no 1,4-dioxane, methylenchloride, tetrahydrofuran, N-methyl pyrrolidone, dimethyl sulfoxide, 1,3 -dimethyl -2 -imidazolidinone, chloroform and / or chlorobenzene is present. Still more preferably, in inventive step (i) no 1,4-dioxane, chloroform and / or chlorobenzene is present. According to the present invention water can be present in process step (i) and / or (ii). This can be intentionally added, for example when the catalyst is firstly dissolved in water and then used in process step (i). Moreover, it is also possible that water is introduced in process step (i) by residual moisture in the multi-layer body. Moreover, in case any solvent (e. g. methanol and / or dimethyl carbonate) is recycled from the inventive process to process step (i), there might be some water in process step (i). Preferably, the amount of water in process step (i) is less than 3 wt.-% with respect to the reaction mixture of step (i). Still preferably, the total amount of any further component present in the reaction mixture in step (i) beside the multi-layer body, methanol, at least one catalyst, optionally dimethyl carbonate, optionally water and optionally any side product which is formed is at most 0.05 molar equivalent, more preferably at most 0.01 molar equivalent compared to 1 molar equivalent of the polycarbonate of the substrate layer A). It is especially preferable that in this case the amount of water in process step (i) is less than 3 wt.-% with respect to the reaction mixture of step (i). The side product of the process could originate from component C) and / or component D). Especially in case of any recycling of e. g. a solvent to process step (i) those might accumulate. Still preferably, the reaction mixture of step (i) essentially consists of the multi-layer body, methanol, at least one catalyst, optionally dimethyl carbonate, optionally water and optionally any side product of the process. It is understood by the skilled person that this does not exclude impurities of the starting materials. Most preferably, the reaction mixture of step (i) consists of the multi-layer body, methanol, at least one catalyst, optionally dimethyl carbonate, optionally water and optionally any side product of the process. According to the present invention it is advantageous to have as few components in the reaction mixture of step (i) as possible. This leads to an easier work up after methanolysis. Moreover, substances that are not that easy to handle (e. g. 1,4-dioxane, chloroform and / or chlorobenzene) and / or are halogenated can be avoided.

[0266] Process step (ii)

[0267] In process step (ii) a methanolysis reaction is performed. This process is known to the skilled person. According to the present invention “methanolysis” preferably refers to a process that depolymerizes polycarbonate to produce dihydroxy compounds and dimethyl carbonate by using methanol. In principle, this reaction is a transesterification. Methanol as alcohol transesterifies the carbonate group2025PF30013-Foreign Countries

[0268] which is bound to the structural unit derived from the dihydroxy compound resulting in a methanol carbonate bond (and if performed twice in dimethyl carbonate) and a degraded polymer chain with a hydroxy end group (and if performed twice at a structural unit of the polycarbonate it results in the dihydroxy compound). By way of example, the following scheme shows the theoretical methanolysis reaction of bisphenol A based polycarbonate (e.g. the reaction which is aimed at, possible side reactions are not shown):

[0269] + 2n H3C-OH

[0270]

[0271] Therefore, the methanolysis reaction is capable of depolymerizing polycarbonate chains to yield at least the dihydroxy compound. The skilled person is aware that a copolycarbonate which comprises more than one structural unit yields more than one dihydroxy compound. Moreover, it was found that small amounts of water can be tolerated in this reaction and do not significantly influence the reaction as shown above. As described above, when using the inventive amounts of the catalyst, the coating layer B) is not degraded by this reaction.

[0272] Process step (ii) is preferably carried out in a temperature range of the reaction mixture from 50 °C to 130 °C, preferably 60 °C to 120 °C, even more preferably 90 °C to 115 °C. Preferably, process step (ii) is conducted at a temperature which is above the glass transition temperature of component C) in case component C) is present. It was found that the overall reaction velocity significantly increases above the glass transition temperature of component C).

[0273] Preferably, the term “in a liquid state” at the end of inventive process step (ii) when referring to component C) refers to the temperature in which process step (ii) is conducted. More preferably, the term “in a liquid state” at the end of inventive process step (ii) when referring to component C) refers even to room temperature. This means that even when the mixture obtained by process step (ii) is cooled to room temperature, component C) preferably is still in the liquid phase.

[0274] Process step (ii) is preferably carried out in a pressure range from 1 bara to 15 bara, preferably 1.5 bara to 13 bara and most preferably 2 bara to 11 bara. Most preferably, process step (ii) is carried out in the above-given temperature range of the reaction mixture and at the above-given pressure range.

[0275] Process step (ii) is preferably carried out for 2 minutes to 20 hours, more preferably for 3 minutes to 5 hours, most preferred for 5 minutes to 1 hours. It is further preferred that the depolymerization of the polycarbonate is at least 95 % complete, further preferred at least 98 % complete, more preferred at least 99%, most preferred at least 99.5 %. A less complete depolymerization of polycarbonate leads to higher2025PF30013-Foreign Countries

[0276] - 40 -amounts of residual oligocarbonates in the product mixture at the end of process step (ii). This not only reduces the yield of the dihydroxy compound which can be recovered but also requires the removal of such oligocarbonates before recovering the dihydroxy compound and optionally the vinyl(co)polymer and / or a rubber-modified graft polymer. It is therefore preferred that the polycarbonate conversion in the process according to the invention is as high as possible. It is understood that this actual yield is not the same as the theoretical yield of 100 % which underlies the calculation of preferred conditions (a) to (c). This means that even if the methanolysis reaction is not carried out to 100 % conversion, the preferred assumption that the methanolysis reaction of the polycarbonate of substrate layer A) is theoretically completed to 100 % for the calculation of preferred conditions (a) to (c) still apply.

[0277] Preferably, process step (i) and / or process step (ii) are conducted under inert atmosphere (e. g. using nitrogen or argon).

[0278] Preferred Conditions (a) to (c)

[0279] The preferred conditions (a) to (c) only apply to the preferred embodiment in which the multi-layer body additionally comprises component C). Accordingly, the following description is directed to the presence of component C). Moreover, for calculating preferred conditions (a) to (c) the presence of the coating layer B) is ignored. This means it does not have an influence an the calculation of the preferred conditions.

[0280] The process according to the present invention is preferably characterized in that the amounts of methanol, polycarbonate in the substrate layer A), component C) and the optionally present dimethyl carbonate before step (ii) are chosen so that the following preferred conditions (a) to (c) are met at the end of step (ii), wherein the preferred conditions (a) to (c) represent weight ratios which are obtained using the assumption that the methanolysis reaction of the polycarbonate of substrate layer A) is theoretically completed to 100 %:

[0281] (a) the weight ratio of dimethyl carbonate: component C) is in the range of 0.5: 1 to 20: 1,

[0282] (b) the weight ratio of methanol: component C) is in the range of 0.79: 1 to 4: 1 and

[0283] (c) the weight ratio of (methanol + dimethyl carbonate): (component C) + dihydroxy compound) is in the range of 0.6: 1 to 20: 1.

[0284] For the skilled person it is clear that the polycarbonate of the substrate layer A) is not present as such in preferred conditions (a) to (c). However, the amount of polycarbonate of substrate layer A) determines how much dihydroxy compound can theoretically be formed by methanolysis. Therefore, as in preferred condition (c) the amount of the dihydroxy compound is present, the initial amount of the polycarbonate of substrate layer A) obviously is related to preferred conditions (a) to (c).2025PF30013-Foreign Countries

[0285] - 41 - Moreover, for the skilled person the expression “before step (ii)“ is clear. As according to the present invention in step (i) a multi-layer body, methanol, a catalyst and optionally dimethyl carbonate are brought into contact it is highly preferred that in step (i) the amounts and ratios of those component are already adjusted so that the conditions of step (ii) are met. This is especially the case, if process steps (i) and (ii) cannot be clearly distinguished. Moreover, it is clear to the skilled person that the weight ratios of the components before step (ii) have an influence on the weight ratios of reaction products at the end of step (ii).

[0286] “The methanolysis reaction of the polycarbonate of substrate layer A) is theoretically completed to 100 %” means that the entirety of the polycarbonate of substrate layer A) (i. e. 100 %) has been depolymerized into its monomers. This implies that all of the structural units derived from a dihydroxy compound which are contained in the polycarbonate are converted into the respective dihydroxy compound. Moreover, this implies that each carbonate group which is present in component A) now is part of dimethyl carbonate (assuming that no side reactions took place). Chain terminators and / or branching points (either intended or due to rearrangement) are ignored when calculating 100 %. This means that it is assumed that the polycarbonate of substrate layer A) only consists of carbonate groups and dihydroxy compounds from which two hydrogen atoms are removed. As explained above, the point where the methanolysis reaction of the polycarbonate is theoretically completed to 100 % does not necessarily mean that in reality the conversion of the polycarbonate of substrate layer t A) and / or the yield of the dihydroxy compound is 100 %. The same holds true for the inventive expression of the “end of step (ii)” at which preferred conditions (a) to (c) are met. For the calculation of preferred conditions (a) to (c) it is assumed that the methanolysis reaction of the polycarbonate of substrate layer A) is theoretically completed to 100 %. This defines the “end of the methanolysis reaction” and thus the “end of process step (ii)”. However, this is just to calculate the amounts and ratios of the components at the beginning of step (ii). The real composition at the end of process step (ii) might deviate from the theoretical composition which is obtained when assuming that the methanolysis reaction is completed to 100 %. This indeed preferably is the case, because for the calculation of a 100 % completed methanolysis reaction different assumptions, e. g. omitting the presence of chain terminators or branching points in the polycarbonate of substrate layer A), are used.

[0287] Preferably, at the end of step (ii) the conversion of the methanolysis reaction is at least 80 %, more preferably at least 90 %, still preferably at least 95 % and most preferably at least 98 % of the theoretical conversion of the methanolysis reaction of the polycarbonate of the substrate layer A) as mentioned above. It is beneficial to have a high “real” conversion in order for the process to be economically and / or ecologically efficient.2025PF30013-Foreign Countries

[0288] - 42 - The skilled person knows how to calculate the weight ratios according to the preferred conditions (a) to (c) by taking into account the amounts of methanol, polycarbonate of substrate layer A), component C) and the optionally present dimethyl carbonate present before step (ii). As explained above, some further assumptions with respect to the polycarbonate of substrate layer A), other additives in the multi-layer body different from polycarbonate and C) and / or side reactions are to be made. By way of example, in the following an explanation is given how to calculate the preferred conditions (a) to (c) for a multilayer body:

[0289] (a) 0.5 < — m(componen —t C) < 20

[0290] (b) 0.79 < — — <

[0291] m(component C)4

[0292] ( \ Q g < > m^MeOH)+m^DMC) < 20

[0293] v 7' m(component C)+m(dihydroxy compound)

[0294] With m^DMC) = > * M(DMC) + m0(DMC), where mi(DMC) is the theoretical mass of

[0295]

[0296] DMC at the end of step (ii) (assuming 100 % conversion of the PC), and mo(DMC) is the mass of the DMC in step (i), m(component C) is the mass of component C) added in step (i), m(PC) is the mass of polycarbonate added in step (i), M(PC) is the molecular weight of the repeating unit of PC being the dihydroxy compound with a carbonate group, without 2H and M(DMC) the molecular weight of DMC being 90.08 g / mol; with m^MeOH) = m0(MeOH) — 2 * > * M(MeOH)'),

[0297]

[0298] where mi(MeOH) is the theoretical mass of MeOH at the end of step (ii) (assuming 100 % conversion of the PC), and mo(MeOH) is the mass of the MeOH to step (i); with m(dihydroxy compound) is the theoretical mass of the dihydroxy compound at the end of step (ii) (assuming 100 % conversion of the PC).

[0299] As can be seen from above, in case of doubt for the calculation of preferred conditions (a) to (c) any presence of a chain terminator and / or branching point in the polycarbonate, the catalyst, any water present and any further components in the multi-layer body which are different from the polycarbonate of substrate layer A) and component C) are not considered. In this context “branching point” preferably refers to any branching agent and / or rearrangement structure.

[0300] In case a multi-layer body comprising end-of-life material or any other multi-layer body of unknown composition is used in step (i) of the present invention, the composition of the multi-layer body has to be analyzed with respect to the kind and amount of the polycarbonate of substrate layer A) and component C) prior to process step (i) (cf. above). The skilled person knows suitable methods for such analysis, for example infrared spectroscopy as explained above. The amount of polycarbonate present2025PF30013-Foreign Countries

[0301] - 43 -in a multi-layer body is the basis for calculating the weight of the hydroxy compound to be produced by the methanolysis reaction. If the exact amount of component C) cannot be determined, preferably the maximum possible amount thereof is considered. The maximum possible amount of component C) is preferably determined by the weight difference of the article and the amount of polycarbonate present therein, for example if the amount of polycarbonate in the multi-layer body has been analyzed to be 60 wt.-%, the maximum possible amount of component C) is 40 wt.-%. If the amount of the coating layer B) cannot be determined, it is attributed to component D), as it does not participate in the methanolysis reaction. Using this assumption, it can be guaranteed that component C) is indeed in a liquid state at the end of process step (ii).

[0302] In preferred condition (a), the weight ratio of dimethyl carbonate: component C) is in the range of 0.5: 1 to 20: 1, preferably in the range of 0.7: 1 to 10: 1, more preferably in the range of 0.8: 1 to 4: 1. In preferred condition (b), the weight ratio of methanol: component C) is in the range of 0.79: 1 to 4: 1, preferably in the range of 1: 1 to 3.9: 1, more preferably in the range of 1.1: 1 to 3.6: 1.

[0303] In preferred condition (c), the weight ratio of (methanol + dimethyl carbonate): (component C) + dihydroxy compound) is in the range of 0.6: 1 to 20: 1, preferably in the range of 0.61: 1 to 5: 1, more preferably in the range of 0.62: 1 to 3: 1.

[0304] It is preferred that a combination of the preferred ranges of the preferred conditions (a) to (c) is met. Preferably, the preferred conditions (a) to (c) of the present invention are:

[0305] (a) the weight ratio of dimethyl carbonate: component C) is in the range of of 0.7: 1 to 10: 1, more preferably in the range of 0.8: 1 to 4: 1,

[0306] (b) the weight ratio of methanol: component C) is in the range of 1: 1 to 3.9: 1, more preferably in the range of 1.1: 1 to 3.6: 1 and

[0307] (c) the weight ratio of (methanol + dimethyl carbonate): (component C) + dihydroxy compound) is in the range of 0.61: 1 to 5: 1, more preferably in the range of 0.62: 1 to 3: 1.

[0308] Surprisingly, it was found that it is beneficial that component C) is in a dissolved and / or emulsified state (i.e. in the liquid phase) at the end of process step (ii) (if component C) is present). Due to preferred conditions (a) to (c) component C) can be in a liquid phase also during process step (ii) (i.e. after an initial reaction time which is preferably short). Firstly, it was found that the reaction velocity of the methanolysis is faster in case component C) is in the liquid phase during and / or at the end of the methanolysis (when compared to the same reaction where component C) not in the liquid phase). Moreover, it was found that the yield of the hydroxy compound is higher. As can be seen from the2025PF30013-Foreign Countries

[0309] - 44 -experiments, the amount of hydroxy compound which is readily separated from component C) after step (ii) is high. It is even higher when compared to a process step (ii) in which component C) is not in a liquid phase (e. g. as slurry or as coating at the reactor wall). This already leads to a higher yield of the hydroxy compound, because the loss of the hydroxy compound which sticks to component C) is smaller. Moreover, the examples surprisingly show that a high amount of hydroxy compound which is stick to component C) can be removed. This increases the yield of the hydroxy compound even further. That is to say that the loss of hydroxy compound is smaller. This is especially the case when compared to a process in which component C) is not in the liquid phase during and / or at the end of the methanolysis reaction. In the end this means that the inventive process provides for a high yield of hydroxy compound. Preferably, the inventive process provides a yield of the hydroxy compound of at least 75 %, more preferably at least 80 %, still preferably of at least 85 %, still preferably of at least 90 %, still preferably of at least 95 % and most preferably of at least 98 %. For the skilled person it is clear that the number of washing steps of component C) contributes to this yield. However, it is not economically and / or ecologically reasonable to have a high number of washing steps. At the same time the purity of component C) which is recovered is very high. This means that the effort for any work up of component C) in order to recycle this component is low.

[0310] According to the present invention it was found that due to the reaction of the methanolysis the solution conditions of process step (ii) continuously change. With the aim to bring and / or keep component C) in a liquid state, this needs to be considered. The terms “dissolve” and / or “in solution” and / or “in a liquid state” preferably mean that, when filtering the liquid in which component C) is present, no solid can be separated off using customary filter methods and / or that the liquid phase remains uniform over time without phase separation. Moreover, it is preferred that the term “in a liquid state” refers to room temperature. Dimethyl carbonate is a good solvent for component C), whereas methanol is an antisolvent. This also means that depending on the chemical nature of component C) dimethyl carbonate can form an emulsion with component C), whereas methanol does not form an emulsion with component C). The term “anti-solvent” is understood by the skilled person. It preferably refers to a liquid which reduces the solubility product of component C) in a given (highly concentrated) solution of component C). This preferably means that it is capable of precipitating component C) from a (highly concentrated) solution of component C). The generated dihydroxy compound is a good solvent for component C), too. During the methanolysis reaction the amounts and ratios of dimethyl carbonate, methanol and the dihydroxy compound change. Methanol is consumed, whereas dimethyl carbonate and the dihydroxy compound is generated. Accordingly, the conditions constantly vary. However, when using the preferred conditions (a) to (c) according to the present invention, the presence of component C) in a liquid state at least at the end of process step (ii) is guaranteed. The amount of component C) in the initial multilayer body is decisive whether dimethyl carbonate needs to be added from or whether the generated2025PF30013-Foreign Countries

[0311] - 45 -dimethyl carbonate is sufficient. In the case where additional dimethyl carbonate is needed to guarantee that component C) is in the liquid state at the end of the methanolysis reaction, it can be added at the very beginning of step (ii) and / or during process step (ii). Moreover, preferred conditions (a) to (c) guarantee that the process is still economically and ecologically advantageous. A high amount of methanol could lower the viscosity of the mixture as obtained after inventive step (ii). However, it could lead to precipitation of component C) and will need to be removed afterwards from the dihydroxy compound. Therefore, in order to keep the process economic and ecological, the amount of methanol should be as low as possible (in the boundaries of the methanolysis reaction).

[0312] Moreover, it was found according to the present invention that when using preferred conditions (a) to (c) the resulting viscosity after performing step (ii) is low and thus, very well manageable. Preferably, the viscosity after performing step (ii) is in the range of not more than 1 000 mPa*s, more preferably of not more than 500 mPa*s, still more preferably of not more than 300 mPa*s, still more preferably of not more than 100 mPa*s and most preferably of not more than 50 mPa*s. Preferably, these viscosity numbers refer to the temperatures used in step (ii). Methods how to determine the viscosity are known to the skilled person. It is apparent that the viscosities are greater than 0 mPa*s and that the lower the viscosity, the easier the workup after step (ii) will be. These indicated viscosities are manageable and at the same time the amount of methanol is not too high so that the process is still economically and ecologically advantageous.

[0313] According to the present invention it was found that the amount of methanol and dimethyl carbonate have more influence on the dissolution of component C) than the dihydroxy compound.

[0314] In order to adjust the ratio of dimethyl carbonate: component C) and the ratio of (methanol + dimethyl carbonate): (component C) + dihydroxy compound) according to the conditions (a) and (c) of the present invention, dimethyl carbonate (DMC) may be added to the reaction mixture of step (i) in the required amount. It is preferable to keep the amount of dimethyl carbonate added to the reaction mixture of step (i) at a minimum. This increases the production efficiency. Additional amounts of dimethyl carbonate lead to an increased volume of the reaction mixture and thus the amount of energy required for heating and mixing, as well as to increased efforts necessary for subsequent workup, e.g. separation of solvents, separation of component C) and side products from the desired products. Furthermore, it is unfavorable to add too large amounts of dimethyl carbonate to the reaction mixture of step (i) as this means that the amount of dimethyl carbonate generated during the methanolysis reaction of step (ii) has to be low. In this case the content of polycarbonate of substrate layer A) in the multi-layer body with respect to the content of component C), both present in the reaction mixture of step (i), is low. Thus, the amount of dihydroxy compound to be recovered is also low. This has a negative impact on the absolute amount of the dihydroxy compound to be obtained based on the mass of the whole multi-layer body making it less2025PF30013-Foreign Countries

[0315] - 46 -economical attractive. It is therefore preferable to add 0 to less than 1.8 mol of dimethyl carbonate relative to 1 mol of dihydroxy compound.

[0316] Alternatively, the ratios of preferred conditions (a) and (c) of the present invention may be adjusted by adjusting the ratio of polycarbonate of substrate layer A): component C) in the reaction mixture of step (i). As the polycarbonate is depolymerized during the methanolysis reaction in step (ii), dimethyl carbonate is generated and thus contributes to the ratios of dimethyl carbonate: component C) and (methanol + dimethyl carbonate): (component C) + dihydroxy compound), respectively. The skilled person can calculate the amount of dimethyl carbonate which is produced under the assumption that the methanolysis reaction of the polycarbonate is completed to 100 %. The ratio of the polycarbonate of substrate layer A): component C) can for example be adjusted by adding further polycarbonate to the reaction mixture of step (i) or by mixing multi-layer bodies with different ratios of polycarbonate: component C). By this the total amount of dimethyl carbonate which is needed can also be influenced and preferred conditions (a) to (c) can be accordingly adjusted. It is preferred to adjust the ratio of polycarbonate: component B) by increasing the amount of polycarbonate) rather than to increase the amount of dimethyl carbonate in order to fulfil preferred conditions (a) to (c).

[0317] Furthermore, it is preferred that the process according to the present invention is characterized in that the amounts of methanol, polycarbonate of substrate layer A), component C) and the optionally present dimethyl carbonate before step (ii) are chosen so that the following preferred conditions (a) to (d) are met at the end of step (ii), wherein the preferred conditions (a) to (d) represent weight ratios which are obtained using the assumption that the methanolysis reaction of the polycarbonate of substrate layer A) is theoretically completed to 100 %:

[0318] wherein preferred conditions (a) to (c) are as described above and

[0319] (d) the weight ratio of dimethyl carbonate: methanol: component C) is in the range of 0.015 to 0.5, more preferably in the range of 0.02 to 0.38 and most preferably in the range of 0.02 to 0.35. This weight ratio is understood as being the quotient of the mass of dimethyl carbonate, the mass of methanol and the mass of component C) and the respective quotient needs to be in the indicated range. According to the present invention, this additionally preferred condition (d) specifically leads to an economically and ecologically advantageous process.

[0320] It is preferred that the amount of polycarbonate of substrate layer A) in the multi-layer body is at least 25 wt.-%, more preferably at least 30 wt.-% and most preferably 36 wt.-%. A high amount of polycarbonate in the multi-layer body increases the overall yield and thus production efficiency of the recovery of the hydroxy compound. More preferably in order to get an economically attractive process, the amount of polycarbonate in the multi-layer body is at least 40 wt.-%, more preferably at least 50 wt.-2025PF30013-Foreign Countries

[0321] - 47 - % and most preferably 60 wt.-%. These amounts of polycarbonate of substrate layer A) preferably relate to the total content of polycarbonate in case a mixture of multi-layer bodies is used.

[0322] Further process steps

[0323] It is preferred that the process according to the present invention further comprises the steps of (iii) separating the coating layer B) from the rection mixture as obtained by step (ii) by a solid liquid separation. This step is possible due to the fact that the coating layer B) is present as solid at the end of process step (ii). This renders the inventive process economically and ecologically advantageous. The solid liquid separation can be achieved by means known to the skilled person, e. g. filtration, sedimentation, decantation and / or centrifugation. Preferably, process step (iii) comprises the step of filtration.

[0324] Moreover, in case the multi-layer body comprises component C), it is preferred that the inventive process further comprises the steps of

[0325] (iv) precipitating component C) from the product as obtained after performing step (iii) to obtain a suspension comprising a solid fraction comprising the vinyl(co)polymer and / or the rubber-modified graft polymer and a liquid fraction comprising the dihydroxy compound and

[0326] (v) separating the solid fraction and the liquid fraction.

[0327] The precipitation of component C) can be achieved by any means known to the skilled person. Preferably, the precipitation of component C) is achieved by lowering the solubility of component C) in the mixture as obtained after performing step (iii), e.g. by lowering the temperature and / or changing the solubility conditions. This can be done either by addition of an anti-solvent or by removal of a solvent. As also defined before “anti-solvent” preferably means a solvent in which a compound is less soluble. If an anti-solvent is used for the precipitation of component C), the anti-solvent preferably is a substance which is present at the end of step (ii) of the inventive process. Most preferably, the anti-solvent is methanol and / or water. Preferably, the precipitation of component C) is achieved by the addition of methanol. This is advantageous, because methanol is already present in the system. This means that the further work-up is advantageous, because no further components need to be removed. It is also advantageous for recovering the methanol. For example, the methanol could be recycled and used in process step (i). Using methanol as anti-solvent in process step (iv) does not add any further components which might have a negative impact on the recyclability of the methanol. However, as indicated before, when recycling methanol the amount some side products and / or water could increase in process step (i).2025PF30013-Foreign Countries

[0328] - 48 - According to the present invention it was found that due to the preferred inventive process a precipitation of component C) is possible. This results in a processable suspension. Preferably, this means that the suspension can be pumped and / or removed from the reactor. In comparison to this if component C) is not in the liquid phase at the end of process step (ii) it sticks to the reactor wall and is difficult to be removed from the reactor.

[0329] The separation of the solid fraction and the liquid fraction of the suspension (process step (v)) can be done by any solid / liquid separation process known to the skilled person, e.g. filtration, sedimentation, decantation and / or centrifugation. Preferably, the solid fraction and the liquid fraction are separated using filtration. It was found that when using the process of the present invention precipitated component C) can be easily filtered off and / or washed. This is due to the fact that component C) forms a fine, powdery residue in form of a suspension of low viscosity. In this context the term “low viscosity” preferably refers to a viscosity of < 20 mPas. It is known to the skilled person that filtration of mixtures with viscosities of > 20 mPas is technically not reasonable. In contrast to this, if component C) is not in the liquid phase after process step (ii) (e. g. comparative examples), it forms a sticky, phase-separated mass of high viscosity (> 20 mPas). Due its high viscosity this mass is not filterable, it cannot be washed with any washing agent and thus, the desired products which might be still present in this mass cannot be removed (e. g. the dihydroxy compound cannot be washed off component C)). Optionally, the solid fraction can be washed after the separation step in order to remove any remaining anti-solvent or other compounds present at the end of step (ii) of the inventive process which are not component (C), e.g. dihydroxy compound, methanol, catalyst and dimethyl carbonate, water, residual oligocarbonates. Preferably, the solid fraction is washed after the separation step. This additional step of washing can be used in order to increase the overall yield of the dihydroxy compound, because by washing component C), remaining dihydroxy compound can be recovered. For the washing for example methanol and / or water can be used.

[0330] Particular preferably, the inventive process is a process wherein a vinyl(co)polymer and / or the rubber-modified graft polymer is recovered and which additionally comprises the steps of isolating the vinyl(co)polymer and / or the rubber-modified graft polymer. Most preferably, in this case, the inventive process comprises inventive process steps (iv) and (v) and a step of isolating the vinyl(co)polymer and / or the rubber-modified graft polymer.

[0331] It was found that when using the inventive process the recyclability of the optionally present vinyl(co)polymer and / or the rubber-modified graft polymer is very good. As explained above, it was found that component C) can be easily separated from any other component that are soluble in the washing liquid present after process step (ii). It has a good quality. It was found that it has a low residual content of dihydroxy compound. Moreover, it has a low residual content of potentially other low2025PF30013-Foreign Countries

[0332] - 49 -molecular, organic compounds beside the dihydroxy compound (such as for example chain terminator and / or potential additives of the polycarbonate such as component D)). Preferably, the recovered vinyl(co)polymer and / or the recovered rubber-modified graft polymer has a low residual BPA content of preferably less than 5 wt.-%.

[0333] The liquid fraction obtained after the separation step (v) can undergo any liquid / liquid separation process known to the skilled person, e.g. distillation or extraction, in order to separate at least methanol and dimethyl carbonate from the dihydroxy compound. Preferably, a mixture comprising at least methanol and dimethyl carbonate and the dihydroxy compound is obtained. It is also possible that a stream comprising methanol and dimethyl carbonate and a stream comprising the dihydroxy compound are obtained.

[0334] The stream comprising methanol and dimethyl carbonate may be reused in the methanolysis of polycarbonates. Preferably, the stream comprising methanol and dimethyl carbonate can be reused in inventive process step (i). This might require exact knowledge of the composition of the stream which is, however, routine experimentation for the skilled person. Alternatively, the stream comprising methanol and dimethyl carbonate can be separated into a methanol-rich stream and a dimethyl carbonate-rich stream. Here it is preferred that the methanol-rich stream contains more than 75 wt.-%, more preferably more than 85 wt.-% and most preferably more than 90 wt.-% methanol. Moreover, it is preferred that the dimethyl carbonate-rich stream contains more than 30 wt.-%, more preferably more than 60 wt.-% and most preferably more than 95 wt.-% dimethyl carbonate. The methanol-rich stream can be reused to depolymerize polycarbonates. Preferably, the methanol-rich stream is reused in inventive process step (i). Furthermore, the methanol- and / or dimethyl carbonate-rich stream can be purified before use in further reactions. This can be done by processes known to the skilled person. The present invention preferably provides a process for the recovery of the dihydroxy compound, further comprising the step of

[0335] (vi) isolating the dihydroxy compound.

[0336] It is understood that it depends on the presence of optional component C) whether process step (vi) is conducted after process step (iii) or after process step (v).

[0337] As said above, preferably after step (iii) or (iv) a liquid fraction is obtained which comprises methanol, dimethyl carbonate and the dihydroxy compound. It is also possible that such a liquid fraction can be obtained from inventive step (ii) other than by inventive steps (iii) and / or (iv) and (v).

[0338] The dihydroxy compound can be isolated from such a liquid fraction comprising methanol, dimethyl carbonate and the dihydroxy compound, preferably after inventive process step (v) by a liquid / liquid2025PF30013-Foreign Countries

[0339] - 50 -separation process. Such processes are known to the skilled person. The purity of the dihydroxy compound can be increased by methods known to the skilled person. The dihydroxy compound can be further purified by one or more extraction and crystallization process steps which is a known method known to the skilled person. Preferably, the recovered dihydroxy compound has a purity of at least 90 %, more preferably of at least 95 % and most preferably of at least 98 %.

[0340] Moreover, using the inventive process it was found that the yield of the dihydroxy compound is very high, especially in addition to the high purity. Preferably, the yield of the dihydroxy compound is at least 70 %, more preferably at least 80 %, most preferably at least 90 %. This yield can be preferably obtained in combination with the above-given purity of the dihydroxy compound. For the skilled person it is understood that the percentage of the yield is based on the amount of component A) which theoretically decomposes to 100 % to the dihydroxy compound. For the calculation of the yield preferably all assumptions as with respect to preferred conditions (a) to (c) are applied which relate to the polycarbonate of substrate layer A). For example for calculating the yield, the presence of chain terminator groups and / or branching points are ignored.

[0341] Due to the use of the inventive process such good quality (e. g. purity) and / or high yield of the dihydroxy compound is obtained using a small effort for washing and / or few purification steps. Thus, low energy consumption is required.

[0342] In a particular preferred embodiment the present invention provides a process comprising inventive steps (i) and (ii) and further comprises the steps of

[0343] (iii) separating the coating layer B) from the rection mixture as obtained by step (ii) by a solid liquid separation,

[0344] (iv) precipitating component C) to obtain a suspension comprising a solid fraction comprising a vinyl(co)polymer and / or a rubber-modified graft polymer and a liquid fraction comprising the dihydroxy compound,

[0345] (v) separating the solid fraction from the liquid fraction of the suspension as obtained in step (iv) and optionally washing the solid fraction to recover the vinyl(co)polymer and / or the rubber-modified graft polymer,

[0346] (vi) removing at least methanol and dimethyl carbonate from the liquid fraction of step (iv) preferably by distillation or evaporation to recover the dihydroxy compound.

[0347] Step (vi) might further comprise at least one, preferably all of the following steps:2025PF30013-Foreign Countries

[0348] - 51 - (vi-1) obtaining a mixture comprising the dihydroxy compound after the distillation or evaporation in step (vi),

[0349] (vi-2) dissolving the mixture of step (vi-1) preferably with toluene to obtain a solution of the hydroxy compound,

[0350] (vi-3) crystallizing the dihydroxy compound from the solution of the hydroxy compound, preferably followed by filtrating the dihydroxy compound,

[0351] (vi-4) drying of the dihydroxy compound.

[0352] In a further aspect of the present invention a process is provided for the production of a polymer comprising the step of polymerizing the dihydroxy compound recovered in the process according to the present invention. It is understood that this inventive process can comprise any of the described steps even in preferred embodiments or in combinations of preferred embodiments.

[0353] Accordingly, the present invention further provides a process for the production of a polymer comprising the step of polymerizing a dihydroxy compound, wherein the hydroxy compound is produced by a process comprising the steps of

[0354] (i) bringing into contact the multi-layer body, methanol, at least one catalyst and optionally dimethyl carbonate to form a reaction mixture, wherein the multi-layer body comprises (A) a substrate layer comprising polycarbonate comprising a structural unit derived from a dihydroxy compound and

[0355] (B) a coating layer comprising urethane bonds,

[0356] (ii) performing a methanolysis reaction of the reaction mixture of step (i) yielding at least the dihydroxy compound from the polycarbonate of substrate layer A),

[0357] characterized in that the amount of the at least one catalyst is in the range of 0.01 to 10 wt.-%, preferably 0.05 to 5 wt.-%, still preferably 0.1 to 1 wt.-% and most preferably 0.2 to 0.5 wt.-% with respect to the polycarbonate of substrate layer A).

[0358] Preferably, the polymer is polycarbonate or an epoxy resin. Most preferable the dihydroxy compound is bisphenol A.

[0359] Furthermore, the invention provides a process for the production of a polymer blend comprising the step of blending the vinyl(co)polymer and / or a rubber-modified graft polymer recovered in the inventive process with a further polymer. It is understood that this inventive process can comprise any of the described steps even in preferred embodiments or in combinations of preferred embodiments.2025PF30013-Foreign Countries

[0360] - 52 - Accordingly, the present invention provides a process for the production of a polymer blend comprising the step of blending the vinyl(co)polymer and / or a rubber-modified graft polymer with a further polymer, wherein the vinyl(co)polymer and / or a rubber-modified graft polymer is recovered using the steps of

[0361] (i) bringing into contact the multi-layer body, methanol, at least one catalyst and optionally dimethyl carbonate to form a reaction mixture, wherein the multi-layer body comprises (A) a substrate layer comprising polycarbonate comprising a structural unit derived from a dihydroxy compound and

[0362] (B) a coating layer comprising urethane bonds,

[0363] (ii) performing a methanolysis reaction of the reaction mixture of step (i) yielding at least the dihydroxy compound from the polycarbonate of substrate layer A),

[0364] characterized in that the amount of the at least one catalyst is in the range of 0.01 to 10 wt.-%, preferably 0.05 to 5 wt.-%, still preferably 0.1 to 1 wt.-% and most preferably 0.2 to 0.5 wt.-% with respect to the polycarbonate of substrate layer A).

[0365] Preferably, the “further polymer” is a thermoplastic polymer, most preferably polycarbonate. Still preferably, the vinyl(co)polymer and / or a rubber-modified graft polymer is ABS, SAN or PMMA. According to the present invention the term “comprising” refers to compositions or process steps which at least contain the indicated features. Moreover, “comprising” preferably revers to “consisting essentially of’. Most preferably, the term “comprising” means “consisting of.2025PF30013-Foreign Countries

[0366] - 53 - Examples

[0367] Analytics:

[0368] Nuclear Magnetic Resonance Spectroscopy (1H NMR):

[0369] The NMR measurements were performed on a Spinsolve 80 Ultra device from magritek at 80 MHz at 300 K. The spectra were normalized to the corresponding resonances of the solvent: 1H: δ = 2.50 ppm (DMSO-d6) or δ = 3.31 ppm (MeOH-d4). The chemical shift was given in ppm. For quantification, a known amount of pyrazine (1H: δ = 8.5 ppm (s)) was added as an internal standard. The NMR spectra were evaluated with the MestReNova software.

[0370] High-Performance Liquid Chromatography (HPLC):

[0371] The quantification of Bisphenol A (BPA) in Acrylonitrile Butadiene Styrene (ABS) was performed using an Agilent Technologies 1260 Infinity II HPLC system. The system included a G7112B pump, G7129A sampler, G7116A thermostat, and G7117A UV detector. A Restek UHPLC PreColumn filter (0.2 μm) was used as a prefilter. The chromatographic separation was achieved on an Agilent ZORBAX Eclipse Plus C18 column (150 mm x 4.6 mm, 5 μm particle size, 95 Å pore size) at 35 °C. The pressure limit was set to > 400 bar. The mobile phases consisted of ultrapure water (Solvent A) and 100 % methanol (Solvent B). The injection volume was 5 μL, and the sampler temperature was maintained at 35 °C. Detection was performed using a diode array detector (DAD) with signals at 254 nm, 278 nm, and 240 nm. The spectrum was recorded from 190 to 400 nm with a data collection rate of 2.5 Hz. Sample preparation involved weighing approximately 50 mg of ABS into a 20 mL screw-cap vial, adding 10 mL of acetonitrile, and sonicating for 10 minutes. The solution was then diluted with water to precipitate the ABS. The diluted solutions were filtered with 0.2 μm PTFE filters before injection. Quantification was performed using an external calibration with seven BPA standards (5.3 to 33.6 ppm). The calibration standards were prepared in the same solvent composition as the sample extracts.

[0372] Gas Chromatography (GC):

[0373] The analysis of isolated Bisphenol-A (BPA), was conducted using an Agilent 6890 gas chromatograph equipped with a flame ionization detector (FID), an automatic injector, and AGILENT Chemstation software (version A.06.03). The chromatographic separation was achieved using a WCOT quartz glass column (Chrompack:nr7749, now Agilent) with CP-Sil 5CB as the stationary phase, an internal diameter of 0.32 mm, a film thickness of 0.4 μm, and a length of 50 meters. For the analysis of BPA in its solid form, 10 mg (±1 mg) of the dried product was placed into a GC vial, followed by the addition of 150 μL of silylation reagent (N-Methyl-N-trimethylsilyltrifluoracetamid (MSTFA)). The mixture was heated on the GC detector's heating block for 10 minutes until fully dissolved, then 250 μL of ethyl2025PF30013-Foreign Countries

[0374] - 54 -acetate was added. The analysis was conducted using hydrogen as carrier gas, with a column flow rate of 4.5 mL / min and a total flow rate of 50 mL / min. The detector gases included air at 400 mL / min, hydrogen at 40 mL / min, and nitrogen at 45 mL / min. The AGILENT ChemStation software was used to automatically calculate the content in percentage, excluding the peaks of the silylation reagent. Any peaks not listed in the calibration table were disregarded, and the chromatogram was visually inspected for foreign components. Calibration and verification were performed according to the specified frequency, using reference samples.

[0375] FT-IR spectroscopy:

[0376] The IR spectra were recorded with an FT-IR spectrometer Alpha II from Bruker at room temperature. The ATR (diamond) measurement principle was used. The spectrum was recorded from 400 cm-1to 4000 cm-1. The analysis of the spectrum was enabled by the OPUS 7,5 and Origin software. The absorption was given in cm-1. The band at 1512 cm-1for BPA was considered, which represents the HCH bending vibration. Carbamates where characterized by the distinct C-0 carbonyl stretching frequency at v = 1736 cm-1.

[0377] Materials:

[0378] Sodium hydroxide (50 wt.% NaOH in H₂O) and methanol (98 %) were purchased from Fischer Scientifics. Dimethyl carbonate (99 %) and toluene (>99.5) were purchased from Sigma Aldrich.

[0379] PC composition 1:

[0380] A) 69.7 wt.% of polycarbonate based on bisphenol A

[0381] B) 29.9 wt.% of ABS made by bulk polymerization having an acrylonitrile:butadiene: styrene ratio of 23:10:67. The weight average molecular weight of the free styrene acrylonitrile copolymer is 160,000 g / mol (measured by gel permeation chromatography (GPC) in tetrahydrofuran against a polystyrene standard)

[0382] C) 0.4 wt.% of additives

[0383] PC composition 2:

[0384] A) 49.05 wt.% of polycarbonate based on bisphenol A

[0385] B) 49.05 wt.% of ABS made by bulk polymerization having an acrylonitrile: butadiene: styrene ratio of 23:10:67. The weight average molecular weight of the free styrene acrylonitrile copolymer is 160,000 g / mol (measured by gel permeation chromatography (GPC) in tetrahydrofuran against a polystyrene standard)

[0386] C) 1.9 wt.% of additives2025PF30013-Foreign Countries

[0387] - 55 - PC composition 3:

[0388] A) 42.75 wt.% of polycarbonate based on bisphenol A

[0389] B) 42.75 wt.% of ABS made by bulk polymerization having an acrylonitrile: butadiene: styrene ratio of 23:10:67. The weight average molecular weight of the free styrene acrylonitrile copolymer is 160,000 g / mol (measured by gel permeation chromatography (GPC) in tetrahydrofuran against a polystyrene standard)

[0390] C) 14.5 wt.% of additives

[0391] PC composition 4:

[0392] A) 44.3 wt.% of polycarbonate based on bisphenol A

[0393] B) 44.3 wt.% of ABS made by bulk polymerization having an acrylonitrile:butadiene: styrene ratio of 23:10:67. The weight average molecular weight of the free styrene acrylonitrile copolymer is 160,000 g / mol (measured by gel permeation chromatography (GPC) in tetrahydrofuran against a polystyrene standard

[0394] C) 11.4 wt.% of additives

[0395] PC composition 5:

[0396] A) 36.8 wt.% of polycarbonate based on bisphenol A

[0397] B) 36.8 wt.% of ABS made by bulk polymerization having an acrylonitrile:butadiene: styrene ratio of 23: 10:67 and 24.5 wt.% of poly(methyl methacrylate) with 1 wt.% methyl acrylate content (Plexiglas® 8H, Rohm). The weight average molecular weight of the free styrene acrylonitrile copolymer is 160,000 g / mol (measured by gel permeation chromatography (GPC) in tetrahydrofuran against a polystyrene standard. The weight average molecular weight of the poly(methyl methacrylate) is 147,000 g / mol (measured by gel permeation chromatography (GPC) in tetrahydrofuran under PMMA calibration).

[0398] C) 1.9 wt.% of additives

[0399] PC composition 6:

[0400] This composition consists of recovered end-of-life material. It was analyzed and its composition was determined as follows: potassium bromide pellets were prepared from the ground original, and infrared spectra was recorded in transmitted light. Using a calibration of known polycarbonate contents, the PC content could be determined. Furthermore, a defined amount of the composition was depolymerized by means of sodium methoxide under reflux. The residue was separated from the solution, washed and dried. Using IR, the residue was found to be essentially PMMA due to the presence of the ester stretching2025PF30013-Foreign Countries

[0401] - 56 -frequency. The amount of PMMA was quantified by gravimetry and set as component B). The resulting content of the single components was found to be approximately as follows:

[0402] A) 36 wt.% of polycarbonate based on bisphenol A

[0403] B) max. 64 wt.% of poly(methyl acrylate ) / poly(methyl methacrylate)

[0404] For the depolymerization of this material, the maximum possible amount of component B) was considered. This means that everything that depolymerized was assumed to be component A) and the whole rest of the sample which was not component A) was assumed to be component B).

[0405] PC composition 7:

[0406] This composition consists of recovered end-of-life material. It was analyzed and its composition was determined as follows: potassium bromide pellets were prepared from the ground original, and infrared spectra were recorded in transmitted light. Using a calibration of known polycarbonate contents, the PC content could be determined. The rest of the IR spectrum gave indication to the presence of ABS as confirmed by the presence of the C-N stretching vibration at v = 2240 cm-1. The content of the single components was found to be approximately as follows:

[0407] A) 75 wt.% of polycarbonate based on bisphenol A

[0408] B) max. 25 wt.% of ABS

[0409] For the depolymerization of this material, the maximum possible amount of component B) was considered. This means that the whole rest of the sample which was not component A) was assumed to be component B).

[0410] PC composition 8:

[0411] A) 81.95 wt.% of polycarbonate based on bisphenol A

[0412] B) 8.65 wt.% of ABS made by bulk polymerization having an acrylonitrile:butadiene: styrene ratio of 23:10:67. The weight average molecular weight of the free styrene acrylonitrile copolymer is 160,000 g / mol (measured by gel permeation chromatography (GPC) in tetrahydrofuran against a polystyrene standard)

[0413] C) 9.4 wt.% of additives

[0414] PC composition 9:

[0415] A) 60.19 wt.% of polycarbonate based on bisphenol A

[0416] B) 38.51 wt% of ABS comprising ABS made by bulk polymerization having an acrylonitrile: butadiene: styrene ratio of 23:10:67. The weight average molecular weight of the free styrene acrylonitrile copolymer is 160,000 g / mol (measured by gel permeation chromatography (GPC) in tetrahydrofuran against a polystyrene standard)

[0417] C) 1.3 wt.% of additives2025PF30013-Foreign Countries

[0418] - 57 - PC composition 10:

[0419] A) 81.95 wt.% of polycarbonate based on bisphenol A

[0420] B) 8.65 wt.% of ABS made by bulk polymerization having an acrylonitrile:butadiene: styrene ratio of 23:10:67. The weight average molecular weight of the free styrene acrylonitrile copolymer is 160,000 g / mol (measured by gel permeation chromatography (GPC) in tetrahydrofuran against a polystyrene standard)

[0421] C) 9.4 wt.% of additives

[0422] Multi-layer body 1:

[0423] Shredded material, particle size: < 5 mm

[0424] A) 86 wt.% of polycarbonate based on bisphenol A

[0425] B) 14 wt% Puroclear 3351 IT purchased from Rühl Group

[0426] Coating layer B) = Composition 2:

[0427] grinded material, particle size: < 1 mm

[0428] B) 100% wt% PU clear coat based on Desmophen® XP 2488 and Desmodur® ultra N 3600 Multi-layer body 3:

[0429] A) 96 wt.% Bayblend® T65 XF: PC / ABS Blend wherein the polycarbonate is based on bisphenol A. B) 4 wt.% PU Coat based on INMOTIQ-Primer WB 2K - R 1472 (obtained from PPG) in combination with Desmodur ultra N 3368 SN, IK waterbased black basecoat based on Neocryl XK-14 / Neopac E-123 / Bayhydrol UH 2606, Permasolid HS Optimum Plus clearcoat 8650 / Permasolid VHS hardener 3225 / Permacron thinner 3380.

[0430] Depolymerization:

[0431] Reference Example 1: In a 1 L reactor, 280.80 g of ground PC composition 1, 259.20 g of methanol (MeOH) and 1.20 g sodium hydroxide (NaOH 50 %) in water as a catalyst were added. The reaction mixture was stirred at 400 rpm and heated to 110 °C for 240 minutes or until a constant bisphenol A (BPA) concentration was reached. The BPA concentration was monitored by online-IR. The reaction solution was then cooled to < 25 °C.

[0432] For this example conditions (a) to (c) were calculated as follows:

[0433] m(component A) = m(composition)2025PF30013-Foreign Countries

[0434] - 58 - m(component A) = m(composition 1) * 0.697 = 195.71 g M component ) = 254 g / mol

[0435] M(DMC) = 90.08 g / mol

[0436] m0(DMC) = 0 g

[0437] m(component B) = m(composistion 1) * 0.299 = 83.96 g (m(component X)

[0438] — - - - - * M(MeOH)

[0439] M (component A) 195.71Q

[0440]

[0441] = 259.20a - 2 * - * 32.04^- = 209.83a 254^-7mo1mol

[0442] z z. M(BPA) m(BPA) = m(component A) * — - - = 195.71 a -228

[0443] 75— = 175.68 a M (component A) 254-^-

[0444]

[0445] mol Calculation of (a) using equation

[0446] > m (DMC) >

[0447] z x > Yn^XpML) > ^ M^(commponent AM(DMC)+m0(DMC)7^7 / 9,^0.03 g / molponent A) >u> > 254 g / mola' > 0 83 m(component B) m(component B) 83.96 g

[0448]

[0449] Calculation of (b) using equation

[0450] > m^MeOH) > 209.83 g >

[0451] Wm(component B) 83.95 g2'5°

[0452]

[0453] Calculation of (c) using equation:

[0454] m^MeOH) + m1(DMC) > 209.83 g + 69.41 g >

[0455]

[0456] m(component B) + m(BPA) 83.96 g + 175.68 g

[0457] Table 1 shows the different reference and comparative examples and polycarbonate compositions which were used according to the above given depolymerization scheme. Comparable reaction setups as given for reference example 1 above were used. If dimethyl carbonate was actively added it was added together with PC, MeOH and the catalyst to the reactor. For all examples complete depolymerization of PC to BPA was ensured via online IR.2025PF30013-Foreign Countries

[0458] - 59 - Precipitation & Filtration:

[0459] The solution obtained from the decomposition of PC composition 1 of reference example 1 was added to a stirred solution of methanol to give a fine non-sticky suspension. The resulting suspension was stirred for 3 minutes and then filtered through a glass frit. The precipitate was washed two times with methanol (V(filter cake) / V(MeOH) = 1 / 1. The filtrate was used in the following step of methanol / DMC evaporation.

[0460] Methanol / DMC evaporation:

[0461] The solvent (methanol / DMC) was removed from the filtrate (containing BPA) using a rotary evaporator.

[0462] Liquid-liquid Extraction & Crystallization:

[0463] The BPA-rich residue remaining after the methanol / DMC evaporation was combined with toluene and with water. The mixture was neutralized by addition of an acid. The water phase and toluene phase were separated at 85 °C through a separation funnel. The toluene fraction was cooled down to a temperature of about 5 °C; under these conditions the bisphenol A crystallizes from the solvent making it possible to selectively separate the bisphenol A crystals through filtration. For the filtration a paper prepleated filter (type Whatman 595 ½) with pore size 4 – 7 μm was used. The resulting residue was combined once again with toluene at 85 °C, cooled to 5 °C and the crystals were filtered once again. The crystals were dried in vacuum oven at 100 °C for 2 hours. B

[0464] Yield isolated BPA: 147.3 g (84%), Purity of BPA (measured by GC): 99.87%2025PF30013-Foreign Countries

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[0504] Ch CM tv o v© a CM o MeOH: component C) IV iv tv o p o ©

[0505] i-— b CM w bx b Ja. Ox bo bo b condition (c): ratio

[0506] CA c* o 8 CM O 00 o (MeOH + DMC):

[0507] (component C) + BPA)

[0508]

[0509] lxe eamp

[0510] 1

[0511] PCiit composon

[0512] lbt poycaronae Reaction input [wt.%] Reaction output (theo.) [wt.%] Ratios [wt.%] t C) componen

[0513] ddiit aves gj

[0514] ■ ©M

[0515] §

[0516] 8 MOHe

[0517] u cu 1

[0518] R-9 4 13.7 13.7 3.5 31 24 4 | DMC5 20.5 12.3 49.9 13.7 3.5 yes 3.63 1.50 2.70 R-10 5 11.4 19.0 0.6 31 27 42 2 MOHe4.1 10.3 46.0 19.0 0.6 yes 94"> 1.27 2.40 R-ll 6 11.2 19.8 n.a. 31 30 39 979 10.0 43.0 19.8 n.a. yes 2.17 1.37 2.35

[0519] BPA

[0520] R-12 7 43.5 14.5 n.a. 58 42 31.0 39.1 15.4 14.5 n.a. yes 1.06 2.14 0.87 R-13 8 48.4 5.1 5.5 59 41 28.8 43.5 1 DMC7.1 5.1 5.5 yes 3.36 5.64 0.95 CE-6 1 39 772 11.7 0.2 61 54.1 24.4 9.6 11.7 02 no 0.83 4.64 1.77

[0521] Ct) componen

[0522] R-14 9 58 35.0 22.4 0.6 42 33.2 31.4 12.4 72.4 0.6 yes 0.55 1.48 0.85 R-15 10 64 52.5 5.5 6.7 35.3 22.0 47.2 18.6 5.5 6.7 yes 3.34 3.96 0.7

[0523]

[0524] jdditi aves 7

[0525] 1

[0526] 1

[0527] a)The amount of PC composition is the sum of polycarbonate, Component C) and 1 A 1d _ditives

[0528] C) fll it componenuyn

[0529] liidttqu sae

[0530] diti ()ti conona: rao

[0531] DMC C)t: componen

[0532] dbiti ()ti conon: rao

[0533] MOH Ct)e componen:

[0534] diti ()it cononc rao: H DMC (MO) +e: ( C) BPA)t +componen2025PF30013-Foreign Countries

[0535] - 62 - As can be seen from table 1, only when using the inventively defined preferred conditions (a) to (c) component C) is in the liquid state after performing step (ii).

[0536] Washing experiments:

[0537] Reference experiment R-l:

[0538] The reaction product of reference example R-l after depolymerization (inventive step (ii)) was added to a stirred solution of MeOH resulting in the formation of a suspension. The suspension was filtered and the BPA content of the solid was analyzed by HPLC to quantify the theoretical loss of BPA yield without washing (cf. Table 2, indicated there as “without washing”). The solid ABS residue was washed with MeOH (v / v of MeOH / wet ABS residue = 1 / 1) dried at 100°C in the vacuum oven for 2 hours and the BPA content in the ABS residue was analyzed by HPLC to quantify the theoretical loss of BPA yield after 1stwashing step (cf. Table 2 1stwashing step). The resulting ABS residue was mixed with MeOH (v / v of MeOH / wet ABS residue = 5 / 1) and was stirred for 10 minutes and filtered. The BPA content of the ABS residue (dried) was analyzed by HPLC to quantify the theoretical loss of BPA yield after 2ndwashing (cf. Table 2, 2ndwashing step).

[0539] For this example loss of BPA yield was calculated as follows:

[0540] Loss of BPA yield = m(BPA in ABS) / m(BPA total)

[0541] Loss of BPA yield [wt%] = m(BPA in ABS) is the mass of BPA in the ABS

[0542]

[0543] residue after filtration which was determined by HPLC-MS and m(BPA total) is the theoretical mass of BPA obtained after complete conversion of component A to BPA.

[0544] Comparative experiment CE-6:

[0545] After the depolymerization reaction (inventive step (ii)) as described above, the resulting reaction solution at 25 °C remained biphasic containing a clear and low viscous upper layer (MeOH phase) and a white, high viscous and non-flowable bottom layer (ABS phase). The BPA content of the bottom layer was analyzed by ’H NMR spectroscopy to quantify the theoretical loss of BPA yield without washing (cf. Table 2, without washing).

[0546] The upper layer (MeOH phase) of the biphasic reaction mixture was removed by decantation. MeOH (v / v of MeOH / bottom layer = 5 / 1) was added to the ABS-rich phase and the mixture was mixed using a orbital shaker for 10 minutes. The upper layer (MeOH phase) was separated by decantation and the BPA content of the bottom layer was analyzed by ’H NMR spectroscopy to the quantify the theoretical loss of BPA yield after the 1stwashing step. (cf. Table 2, 1stwashing step). The washing step was2025PF30013-Foreign Countries

[0547] - 63 -repeated followed by analysis of the BPA content of the bottom layer by ’H NMR spectroscopy to quantify the theoretical loss of BPA yield after the 2ndwashing step. (cf. Table 2, 2ndwashing step). For this example loss of BPA yield was calculated as follows:

[0548] m(BPA in ABS)

[0549] Loss of BPA yield [wt%]

[0550]

[0551] m(BPA total)

[0552] Where m(BPA in ABS) is the mass of BPA in the ABS rich phase after phase separation which was determined by ’H NMR spectroscopy and m(BPA total) is the theoretical mass of BPA obtained after complete conversion of component A to BPA.

[0553] Table 2

[0554] Loss of BPA yield [%]

[0555] Without washing 1stwashing step 2ndwashing step R-l 14.3 3.8 0.9

[0556] CE-6 38 36 23

[0557]

[0558] As can be seen from Table 2 the inventive process provides for a higher BPA yield or a lower loss in BPA yield when performing the same numbers of washing steps and compared to a process in which the ABS was not in the liquid form to result a homogeneous solution and / or stable emulsion. As can be seen already the initial loss of BPA yield is much lower for the inventive example when compared to the comparative example. Moreover, the BPA can be removed more easily from the ABS which can be especially seen after the first washing step. In the inventive example the loss of BPA yield is reduced about 10 % after the first washing step, whereas for the comparative example this reduction is only 2 %.

[0559] Inventive Example 1 (E-l):

[0560] Depolymerization:

[0561] In a 1 L reactor, 65 g of shredded (<5 mm) multi-layer body 1, 52 g of methanol (MeOH) and 0.8 g sodium hydroxide (NaOH 50 %) in water as a catalyst were added. The reaction mixture was stirred at 800 rpm and heated to 110 °C for 60 minutes, or until a constant bisphenol A (BPA) concentration was reached. The BPA concentration was monitored by online-IR. The reaction solution was then cooled to < 25 °C. The reaction mixture yielded a heterogeneous system containing solid residues that maintained the original macroscopic shape of the shredded material. These residual structures appeared as hollow, highly brittle shells, indicating complete dissolution of the substrate (polycarbonate) while preserving the original geometric form of the material fragments (polyurethane coating).2025PF30013-Foreign Countries

[0562] - 64 - Filtration:

[0563] The reaction mixture obtained from the decomposition of multi-layer body 1 of inventive example 1 fdtered through a glass frit. The residue was washed two times with methanol (V(filter cake) / V(MeOH) = 1 / 1. The fdtrate was used in the following step of methanol / DMC evaporation. After filtration the residue was analyzed by FT-IR spectroscopy confirming the presence carbamate groups due to the distinct C-0 carbonyl stretching frequency at v = 1736 cm-1.

[0564] Methanol / DMC evaporation:

[0565] The solvent (methanol / DMC) was removed from the filtrate (containing BPA) using a rotary evaporator. Liquid-liquid Extraction & Crystallization:

[0566] The BPA-rich residue remaining after the methanol / DMC evaporation was combined with toluene and with water. The mixture was neutralized by addition of an acid. The water phase and toluene phase were separated at 85 °C through a separation funnel. The toluene fraction was cooled down to a temperature of about 5 °C; under these conditions the bisphenol A crystallizes from the solvent making it possible to selectively separate the bisphenol A crystals through filtration. For the filtration a paper prepleated filter (type Whatman 595 ½) with pore size 4 – 7 μm was used. The resulting residue was combined once again with toluene at 85 °C, cooled to 5 °C and the crystals were filtered once again. The crystals were dried in vacuum oven at 100 °C for 2 hours.

[0567] Yield isolated BPA: 86%

[0568] Purity of BPA (measured by GC): 99.90%

[0569] Comparative Example 1 (CE-7):

[0570] Experimental procedure for depolymerization was used as described in E-l except that composition 2 (coating layer 2) and higher amounts of caustic were used (cf. Table 3). Before reaction the combined reaction input was low viscous, colorless and clear. After reaction a yellowish, milky mixture was obtained of higher viscosity.

[0571] Reference Example 2 (RE-16):

[0572] Experimental procedure for depolymerization was used as described in E-l except that composition 2 (coating layer 2) was used. Before reaction the combined reaction input was low viscous, colorless and clear. After reaction a slightly yellowish, clear mixture was obtained of low viscosity.2025PF30013-Foreign Countries

[0573] - 65 - Inventive Example 2 (E-2)

[0574] Depolymerization

[0575] Experimental procedure for depolymerization was used as described in E-l except that multi-layer body 3 was used. Reaction input is described in Table 3.

[0576] Precipitation & Filtration

[0577] The solution obtained from the decomposition of multi-layer body 3 of inventive example 2 was added to a stirred solution of methanol to give a fine non-sticky suspension. The resulting suspension was stirred for 3 minutes and then filtered through a glass frit. The precipitate was washed two times with methanol (V(filter cakc) / V(McOH) = 1 / 1. The residue is analyzed by FT-IR spectroscopy confirming the presence carbamate groups due to the distinct C-0 carbonyl stretching frequency at v = 1736 cm-1. The filtrate was used in the following step of methanol / DMC evaporation.

[0578] Methanol / DMC evaporation, liquid-liquid Extraction & Crystallization:

[0579] Experimental procedure for Methanol / DMC evaporation, liquid-liquid Extraction & Crystallization was used as described in E-l. Yield and purity of BPA are given in table 3.

[0580] Table 3

[0581] Reaction input Yield

[0582] Example Multi-layer Multi-layer MeOH NaOH BPA BPA

[0583] body body [g] [g] (50% in yield [%] purity water) [%]

[0584] [g]

[0585] E-l 1 60 65 0.5 86 99.90

[0586] CE-7 2 8 90 60 n.d. n.d.

[0587] RE-16 2 10 100 0.4 n.d. n.d.

[0588]

[0589] E-2 3 90 65 0.8 80 99.77

[0590] The inventive examples E-l and E-2 confirm the complete depolymerization of polycarbonate to BPA in a multi-layer body whereas the PU coating remains intact if amounts of NaOH are used which are inventively defined. CE-7 shows that the PU-coating is at least partially depolymerized when using higher amounts of catalyst. This is indicated by the increased viscosity of the reaction mixture of CE-7 which is in sharp contrast to the low viscous reaction mixture observed in RE- 16 by using catalytic amounts of NaOH. In conclusion, the use of inventively defined amounts of NaOH enables complete separation of the PU-coating from the BPA-rich phase by filtration.

Claims

2025PF30013-Foreign Countries- 66 - Claims:

1. A process for the recovery of a dihydroxy compound from a multi-layer body comprising the steps of(i) bringing into contact the multi-layer body, methanol, at least one catalyst and optionally dimethyl carbonate to form a reaction mixture, wherein the multi-layer body comprises (A) a substrate layer comprising polycarbonate comprising a structural unit derived from a dihydroxy compound and(B) a coating layer comprising urethane bonds,(ii) performing a methanolysis reaction of the reaction mixture of step (i) yielding at least the dihydroxy compound from the polycarbonate of substrate layer A),characterized in that the amount of the at least one catalyst is in the range of 0.01 to 10 wt.-%, preferably 0.05 to 5 wt.-%, still preferably 0.1 to 1 wt.-% and most preferably 0.2 to 0.5 wt.-% with respect to the polycarbonate of substrate layer A).

2. The process according to claim 1, wherein the process comprises the additional step of(iii) separating the coating layer B) from the rection mixture as obtained by step (ii) by a solid liquid separation.

3. The process according to claim 1 or 2, wherein in step (ii) a catalyst is used which is selected from the group consisting of alkali metal or earth alkali metal hydroxides, alkali metal or earth alkali metal carbonates, alkali metal or earth alkali metal alkoxides, alkali metal or earth alkali metal oxides, alkylamines, and pyridine.

4. The process according to any one of claims 1 to 3, wherein the multi-layer body additionally comprises(C) at least one vinyl(co)polymer and / or a rubber-modified graft polymer.

5. The process according to claim 4, wherein the process additionally is for the recovery of the at least one vinyl(co)polymer and / or a rubber-modified graft polymer.

6. The process according to claim 2 and 5, further comprising the steps of(iv) precipitating component C) from the liquid product as obtained after performing step (iii) to obtain a solid fraction comprising the vinyl(co)polymer and / or the rubber-modified graft polymer and a liquid fraction comprising the dihydroxy compound and2025PF30013-Foreign Countries- 67 - (v) separating the solid fraction and the liquid fraction.

7. The process according to claim 6, further comprising the step of(vi) isolating the dihydroxy compound.

8. The process according to any one of claims 1 to 7, wherein the dihydroxy compound comprises at least one compound of formula (1)wherein each Z independently represents a single bond, -S(=O)2-, -C(=O)-, -O-, -S-, -S(=O)-, -CH(CN)-, linear or branched C1-C6-alkylene which optionally comprises at least one carbonyl-group, optionally comprises at least one halogen atom and / or optionally is interrupted by at least one heteroatom, C2-C10-alkylidene which optionally comprises at least one carbon-carbon-double bond, optionally comprises at least one carbonyl-group and / or optionally comprises at least one halogen atom, C5-C12-cycloalkylene, wherein the cycloaliphatic group is fused to at least one further cycloaliphatic ring, C5-C15-cycloalkylidene wherein the cycloaliphatic group is optionally fused to at least one cycloaliphatic and / or at least one aromatic ring, C7-C20-aralkylidene, C8-C20-aralkylene, C6-C12-arylene optionally being fused to further aromatic rings which optionally may comprise at least one hetero atom, formula (Bl- A), formula (Bl-B), formula (Bl-C) or formula (Bl-D)(Bl-C) (Bl-D), wherein in formulae (Bl -A), (Bl-B) and (Bl-C) each R’ independently represents a linear Ci-C4-alkyl, branched C3-C7-alkyl, aralkyl or aryl and the “C*” indicates the quaternary carbon atom which is at the position indicated as “Z” in formula (3), andwherein in formula (Bl-D) each R’ independently represents a linear Ci-C4-alkyl, branched C’s-CT-alkyl. each R” independently represents a linear Ci-C4-alkylene, branched C3-C4-alkylene, each R’” independently represents H or linear Ci-Cs-alkyl, s is 0 to 2 and each si independently is 0 or 1, and the “*” indicate the bonds which link “Z” to the aromatic rings in formula (3),each R5and R6independently represents H, Ci-Cis-alkyl, Cs-Ce-cycloalkyl, C1-C5-alkenyl-, Ci-Cis- alkoxy, phenoxy, halogen atom, Ce-Cis-aryl or Cy-Cis-aralkyl. and2025PF30013-Foreign Countries- 68 -each of pl and ql is 1 to 4.

9. The process according to any one of claims 1 to 8, wherein at least 2 molar equivalents of methanol compared to 1 molar equivalent of the structural unit derived from the dihydroxy compound in the polycarbonate of the substrate layer A) are used.

10. The process according to any one of claims 1 to 9, wherein the (B) coating layer comprising urethane bonds is a multi-layer system comprising a primer surfacer, a basecoat layer and a clearcoat layer.

11. The process according to claim 10, wherein the primer layer is obtained from a solventbome or aqueous primer surfacer.

12. The process according to any one of claims 10 or 11, wherein the basecoat layer is obtained from a one component aqueous system.

13. The process according to any one of claims 10 to 12, wherein the clearcoat layer is obtained by curing at least one polyisocyanate, at least one NCO-reactive compound in the presence of at least one catalyst.

14. A process for the production of a polymer blend comprising the step of blending the vinyl(co)polymer and / or a rubber-modified graft polymer recovered in the process of claim 5 or 6 with a further polymer.

15. A process for the production of a polymer comprising the step of polymerizing the dihydroxy compound recovered in the process according to any of the claims 1 to 13.

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