Coated article

Abstract

The present invention relates to an article comprising a carrier provided at least in part with a coating layer, wherein i) said carrier comprises or consists of a thermoplastic composition, said thermoplastic composition comprising polycarbonate, ii) said coating layer is applied directly on said carrier and comprises or consists of polyurethane obtained by reacting at least one di-or-tri-isocyanate and at least one polyol, iii) said polycarbonate comprises, based on the weight of the polycarbonate, at least 50 wt.% of a first polycarbonate having a terminal hydroxyl content of at least 500 ppm.

Description

[0001] 24POLY0092-PCT 1 IPL

[0002] COATED ARTICLE

[0003] The present invention relates to a coated article. More in particular the present invention relates to an article comprising a carrier and a polyurethane coating layer applied directly on at least part of said carrier, wherein said carrier comprises or consists of a thermoplastic composition comprising polycarbonate.

[0004] Polycarbonate or polycarbonate based compositions are well known for their use in automotive applications, both exterior and interior. In order to protect such articles from scratching, weathering or chemicals a protective coating is typically applied. For example, head-lenses made out of polycarbonate are generally provided with a hardcoat of a few micrometers thick. Typically these are acrylic or siloxane based coatings.

[0005] In the automotive industry new requirements and standards are being put in place relating to the impact properties of front panels of automotive vehicles, in particular electric automotive vehicles. These requirements specify that front parts, such as front panels, should cause minimal damage to humans or animals in case of an accident, i.e. upon impact with a human or animal. This may be accomplished if in the respective part formation of sharp and / or brittle parts, resulting from the impact, is avoided. Similarly front parts should not break or be damaged by the impact. To an extent these requirements are being addressed by the actual design of the panel or part, yet at least in part these requirements are also affected by the properties of the coated part or panel. Thus, it is preferred that the part or panel shows at most ductile impact failure rather than brittle impact failure.

[0006] Apart from mechanics there is also an aesthetic requirement that the coating adheres sufficiently to the carrier and does not delaminate over time. This requirement is of particular importance for interior automotive applications like interior trim bezels, such as those integrated into the console, instrument panels or door panels. With regards to exterior automotive applications the provision of a coating allows not only for a layer of protection for the underlying thermoplastic carrier but also allows for an aesthetic effect similar to that obtained by coating a traditional metal or aluminum part. 24POLY0092-PCT 2 IPL

[0007] It is therefore an object of the present invention to provide for a coated article with sufficient or improved coating adhesion and / or wherein any negative effect of the coating on the mechanical properties of the carrier, i.e. the uncoated article, is reduced to a minimum or is even improved.

[0008] In the prior art interactions between polyurethane and polycarbonate has been disclosed.

[0009] US2019 / 0232621 discloses a multi-layer article comprising i) a dense substrate layer including a polymeric composition, wherein the polymeric composition is a blend comprising a polycarbonate polymer, a toughening component including a rubber - modified monovinylidene aromatic thermoplastic including an impact modifier, and a filler including a wollastonite and ii) a cover layer of a polyurethane bonded directly to the dense substrate layer; wherein the amount of polyester in the polymeric composition is about zero or less than about 5 weight percent. According to this reference it was found that a substrate formed of an ABS (and particularly a mass ABS ) in combination with a specified maximum amount of polycarbonate together with a wollastonite filler results in improved adhesion performance (initial adhesion and adhesion after climate ageing) when overmoulded or painted with a polyurethane layer.

[0010] US2019 / 0153218 discloses a composite component comprising a) a carrier composed of a thermoplastic composition comprising

[0011] A) 55 to 75 parts by weight of at least one polymer selected from the group consisting of aromatic polycarbonate and aromatic polyester carbonate;

[0012] B ) 25 to 45 parts by weight of at least one mixture comprising at least one polybutadiene - based graft polymer prepared by emulsion, suspension or solution polymerization and at least one polybutadiene free vinyl (co) polymer; and

[0013] C) 0.1 to 20.0 parts by weight (based in each case on the sum total of components A and B ) of at least one polymer additive, where the polybutadiene content based on the sum total of the parts by weight of components A and B is 10 % to 20 % by weight; wherein the total content of butadiene - free vinyl (co) polymer from component B based on the sum total of the parts by weight of components A and B is 12% to 23% by weight, and where the sum total of the parts by weight of components A and B in the polycarbonate composition is normalized to 100; and b) at least one polyurethane layer selected from the group consisting of coating materials, foams and compact skins, 24POLY0092-PCT 3 IPL comprising at least one poly-isocyanate component; least one polyfunctional H - active compound; and optionally at least one polyurethane additive and / or processing aid; having a molar ratio of NCO- to H- active groups of 1 :1 to 1 .1 : 1 .

[0014] US 2002 / 01670177 discloses a polycarbonate composition comprising (A) an aromatic polycarbonate and / or polyester-carbonate (B) a graft polymer and (C) a copolymer of styrene and at least one monomer containing at least one carboxyl group, the copolymer having a weight average molecular weight, M, equal to or greater than 10,500 g / mol. According to this reference it was found that the addition of the copolymer (C) a considerable improvement in foam adhesion, in particular the foam adhesion with respect to polyurethane foams can be achieved.

[0015] US 5,688,837 discloses a method for adhering polyurethane foam to polycarbonate comprising a) providing nucleophilic reactive radicals on a polycarbonate surface, b) generating a polyurethane mix comprising at least one polyol and at least one diisocyanate, wherein said polyurethane mix exhibits an isocyanate index of greater than 82, and c) foaming the polyurethane mix on said polycarbonate surface. According to this reference the polycarbonate must have at least one type of nucleophilic reactive radical on its surface. The nucleophilic reactive radicals can be provided by processing as the polycarbonate is manufactured. Nucleophilic reactive radicals can be formed on the polycarbonate during polymerization. For example, bisphenol A polycarbonate that has been produced by a melt transesterification process contains hydroxyl nucleophilic reactive radicals.

[0016] US 2011 / 0027575 discloses a method for producing a composite material, comprising (i) producing a foamed polycarbonate moulding composition by injection moulding using chemical and / or physical foaming techniques, and (ii) applying a polyurethane reaction system on top of said polycarbonate moulding composition and allowing to cure.

[0017] US 2006 / 0151911 discloses a process for in-mold coating comprising (i) obtaining a mold having at least two cavities, (ii) molding a thermoplastic substrate in a first cavity, (iii) introducing the substrate into a second cavity, (iv) coating said substrate with lacquer, the coating being carried out under enhanced pressure and curing the lacquer. The 24POLY0092-PCT 4 IPL method disclosed in this reference is said to be suitable for layer thicknesses of the lacquer in the range of from 0.01 to 3 mm.

[0018] W02024 / 017706 discloses a method for producing composite components with improved interlaminar bonding, the components comprising a carrier, comprising polycarbonate and at least one polyurethane layer that is in direct contact with this carrier. The invention also relates to composite components with improved interlaminar bonding, and to the use of a polycarbonate with defined OH content as a carrier material in the production of composite components with improved interlaminar bonding.

[0019] EP 4309865 discloses a method for producing composite components with improved interlaminar bonding, the components comprising a carrier, comprising polycarbonate and at least one polyurethane layer that is in direct contact with this carrier. The invention also relates to composite components with improved interlaminar bonding, and to the use of a composition comprising polycarbonate and a special hydroxyl-group component as a carrier material in the production of composite components with improved interlaminar bonding.

[0020] The present invention generally relates to an article comprising a carrier provided at least in part with a coating layer, wherein said carrier comprises or consists of a thermoplastic composition, said thermoplastic composition comprising polycarbonate (A), said coating layer is applied directly on said carrier and comprises or consists of polyurethane obtained by reacting at least one di-or-tri-isocyanate and at least one polyol, said polycarbonate comprises, based on the weight of the polycarbonate, at least 50 wt.% of a first polycarbonate (A1) having a terminal hydroxyl content of at least 500 ppm, preferably at least 700 ppm, determined in accordance with the method set out herein.

[0021] More in particular relates to the articles and method as defined in the appended claims, with further preferred and / or alternative embodiments described herein. 24POLY0092-PCT 5 IPL

[0022] Thus, the present invention is directed at an article comprising a carrier provided at least in part with a coating layer, wherein said carrier comprises or consists of a thermoplastic composition, said thermoplastic composition comprising polycarbonate (A), said coating layer is applied directly on said carrier and comprises or consists of polyurethane obtained by reacting at least one poly-isocyanate and at least one polyol, said polycarbonate (A) comprises, based on the weight of the polycarbonate, at least 50 wt.% of a first polycarbonate (A1) having a terminal hydroxyl content of at least 500ppm, preferably at least 700 ppm, determined in accordance with the method set out herein, the article further comprises a transition layer having a thickness, located between the coating layer and the carrier, wherein said transition layer is obtained by the application of said coating to said carrier, the thickness of the transition layer is lower compared to a transition layer obtained under identical article manufacturing conditions and by application of an identical coating and by application of an otherwise identical thermoplastic composition except that the first polycarbonate (A1) has a terminal hydroxyl content such that the terminal hydroxyl content of the polycarbonate (A) is less than 250 ppm, preferably at most 150ppm, wherein the thickness of the transition layer is determined in accordance with the method set out herein and defined as the distance wherein the concentration of polyurethane transitions from 90% to 50%.

[0023] Preferably, the thickness of the transition layer is at most 1 .0 pm, preferably at most 0.8 pm, preferably at most 0.6 pm.

[0024] An important aspect of the present invention resides in the finding that the adhesion of a two-component polyurethane coating applied on a polycarbonate or polycarbonate containing thermoplastic composition is enhanced if the polycarbonate has a certain minimum amount of hydroxyl groups, in particular terminal phenolic hydroxyl groups.

[0025] The present inventors however further investigated test specimens in accordance with the basic concept and concluded that the quality of adhesion not only relates to the combination of materials being used but also to the coating application method. To that extent the present inventors were able to identify that this combination can be captured 24POLY0092-PCT 6 IPL in what is disclosed herein as a “transition layer”, which is to be understood as a layer wherein the polyurethane concentration transitions from 90% to 50%. This transition layer is formed during, and as a direct result of, the coating process.

[0026] Without willing to be bound to it the present inventors consider that upon initial contact of the coating mixture, which is not yet cured at that time, some polycarbonate comprised in the carrier dissolves in the coating mixture resulting in a diffusion of polycarbonate molecules in a direction away from the carrier surface. Polycarbonate with a higher terminal hydroxyl content will react with the coating mixture and as such will be more limited in their diffusion away from the carrier. Similarly, the process conditions applied for the coating process will also influence the reactivity and thus the diffusion rate of the polycarbonate and accordingly will influence a thickness of the transition layer as defined herein. Based on this concept, the present inventors consider that the strength of adhesion between a polyurethane coating and the carrier (comprising or consisting of polycarbonate) relates to the thickness of the layer at the coating-carrier interface wherein the polyurethane concentration transitions from 90% to 50%. For the purpose of the present invention this is referred to as the thickness of the transition layer.

[0027] Alternatively or in addition to the thickness of the transition layer defined herein, the present inventors consider that the absolute value of the slope of a straight line over a distance wherein the concentration of polyurethane transitions from 98% to 50%, expressed in % per micrometer is also indicative for the quality of the coating. Thus the transition slope is defined herein as |48 / Ax| wherein Ax is the distance at the carriercoating interface over which the polyurethane concentration transitions from 98% to 50%. For the avoidance of doubt it is noted that this distance is determined in a direction perpendicular to the carrier-coating interface.

[0028] Accordingly, the present invention further relates to an article comprising a carrier provided at least in part with a coating layer, wherein

[0029] - said carrier comprises or consists of a thermoplastic composition, said thermoplastic composition comprising polycarbonate (A),

[0030] - said coating layer is applied directly on said carrier and comprises or consists of polyurethane obtained by reacting at least one poly-isocyanate and at least one polyol, 24POLY0092-PCT 7 IPL

[0031] - said polycarbonate (A) comprises, based on the weight of the polycarbonate, at least 50 wt.% of a first polycarbonate (A1) having a terminal hydroxyl content of at least 500ppm, preferably at least 700 ppm, determined in accordance with the method set out in the description,

[0032] - the article further comprises a transition layer having a thickness located between the coating layer and the carrier and having a transition slope, wherein said transition layer is obtained by the application of said coating to said carrier,

[0033] - the absolute value of the transition slope is higher compared to a transition slope obtained under identical article manufacturing conditions and by application of an identical coating and by application of an otherwise identical thermoplastic composition except that the first polycarbonate (A1) has a terminal hydroxyl content such that the terminal hydroxyl content of the polycarbonate (A) is less than 250 ppm, preferably at most 150ppm, wherein the transition slope is determined in accordance with the method set out herein and defined as the absolute value of the slope of a straight line over a distance wherein the concentration of polyurethane transitions from 98% to 50%, expressed in % per micrometer.

[0034] The transition slope, determined in accordance with the method disclosed herein is preferably at least 15, preferably at least 16, more preferably at least 20, most preferably from 25 to 75, such as from 25 to 50, expressed in % per micrometer.

[0035] It was found that the process conditions applied during the coating process influence the transition slope.

[0036] Preferred features described herein in the context of the transition layer also apply to the invention defined in terms of the transition slope.

[0037] Preferably the invention disclosed herein is directed at an article comprising a carrier provided at least in part with a coating layer, wherein said carrier comprises or consists of a thermoplastic composition, said thermoplastic composition comprising polycarbonate (A), said coating layer is applied directly on said carrier and comprises or consists of polyurethane obtained by reacting at least one poly-isocyanate and at least one polyol, 24POLY0092-PCT 8 IPL said polycarbonate (A) comprises, based on the weight of the polycarbonate, at least 50 wt.% of a first polycarbonate (A1) having a terminal hydroxyl content of at least 500ppm, preferably at least 700 ppm, determined in accordance with the method set out in the description, the article further comprises a transition layer having a thickness and a transition slope, said transition layer being located between the coating layer and the carrier, wherein said transition layer and said transition slope are obtained by the application of said coating to said carrier, the absolute value of the transition slope is higher compared to a transition slope obtained under identical article manufacturing conditions and by application of an identical coating and by application of an otherwise identical thermoplastic composition except that the first polycarbonate (A1) has a terminal hydroxyl content such that the terminal hydroxyl content of the polycarbonate (A) is less than 250 ppm, preferably at most 150ppm, wherein the transition slope is determined in accordance with the method set out herein and defined as the absolute value of the slope of a straight line over a distance wherein the concentration of polyurethane transitions from 98% to 50%, expressed in % per micrometer, and

[0038] - the thickness of the transition layer is lower compared to a transition layer obtained under identical article manufacturing conditions and by application of an identical coating and by application of an otherwise identical thermoplastic composition except that the first polycarbonate (A1) has a terminal hydroxyl content such that the terminal hydroxyl content of the polycarbonate (A) is less than 250 ppm, preferably at most 150ppm, wherein the thickness of the transition layer is determined in accordance with the method set out in the description and defined as the distance wherein the concentration of polyurethane transitions from 90% to 50%.

[0039] In such embodiment preferably:

[0040] - the transition slope is at least 15, preferably at least 16, more preferably at least 20, most preferably from 25 to 75, such as from 25 to 50, expressed in % per micrometer,

[0041] - the thickness of the transition layer is at most 1.0 pm, preferably at most 0.8 pm, preferably at most 0.6 pm.

[0042] For the sake of clarity and as will be appreciated by a skilled person, the term “thickness of the transition layer” has a specific meaning and refers to the distance over which the concentration of polyurethane changes from 90 to 50% as determined in accordance 24POLY0092-PCT 9 IPL with the method disclosed herein. Obviously the polyurethane concentration at the interface between the coating and the carrier transitions from 100% in the coating layer to 0% in the thermoplastic composition constituting the carrier. For this reason the terms “thickness of transition layer” and “transition slope” can co-exist and both together describe the interface layer (or transition layer), between the carrier and the coating.

[0043] Preferably, the article is a vehicle interior article comprised in or constituting a dashboard, an instrument panel, a console, a display, functional surface trims or door trims, or the article is a vehicle exterior article comprised in or constituting a front, side or rear panel of a vehicle. The exterior article may also be comprised in or constitute a roof panel, engine hood or tailgate.

[0044] In another preferred application the article is comprised in or constitutes the housing of electrical or electronic devices, such as mobile communication devices, in particular mobile phones, , tablets or laptop computers, or the housing of appliances such as household equipment like vacuum cleaners, food processing equipment, coffee machines and the like.

[0045] Preferably, the polycarbonate (A) in the article according to the present invention has an endcap level (EC%) of at most 85%, as calculated with Formula I ppmOH X Mn

[0046] %EC = 100 - . 340000 wherein %EC is the endcap level, ppmOH is the terminal hydroxyl content in parts per million by weight and Mn is the number average molecular weight of the polycarbonate based on polycarbonate standards and determined using gel permeation chromatography.

[0047] Preferably, the polycarbonate (A) in the article according to the present invention has a melt volume rate of from 5 - 40 cm3 / 10 min. as measured in accordance with ISO 1133 (1.2 kg, 300°C).

[0048] Preferably, the thermoplastic composition in the article according to the present invention comprises a polymer selected from the group consisting of poly-ethyleneterephthalate, IPL poly-butyleneterephthalate, acrylonitrile-butadiene-styrene copolymer, styreneacrylonitrile copolymer, optionally functionalised polypropylene, optionally functionalised polyethylene, optionally functionalised polyolefin elastomer, (meth)acrylic acid- polybutadiene core- shell copolymers, and mixtures of at least two of the foregoing.

[0049] Without willing to be bound to it the present inventors are of the opinion that the improved adhesion of the coating is obtained because part of the isocyanate groups of the two- component polyurethane coating reacts with the phenolic OH groups that are naturally present on the melt polycarbonate chains. From these bonded isocyanate groups polyurethane chains may grow forming an at least partially cross-linked coating layer that is chemically bonded to the carrier.

[0050] The carrier as referred to in the context of the present invention comprises or consists of a thermoplastic composition that contains polycarbonate and wherein the polycarbonate comprises, based on the weight of the polycarbonate, at least 50 wt.% of a first polycarbonate having a terminal hydroxyl content of at least 500ppm, preferably at least 700 ppm.

[0051] The carrier is typically obtained by moulding the thermoplastic composition such as injection moulding, extrusion moulding or compression moulding, preferably by injection moulding. Preferably the carrier consists of the thermoplastic composition. However, the carrier may also comprise further components such as compositions other than the thermoplastic composition that are in contact with the part of the carrier manufactured from the thermoplastic composition. For example, the carrier may be molded from two compositions wherein a first surface part of the carrier consists of the thermoplastic composition and another surface part does not consist of the thermoplastic composition. In the context of such an embodiment the coating layer is applied at least in part on the surface of the carrier consisting of the thermoplastic composition. Typically though, and in a preferred embodiment the carrier consists of the thermoplastic composition and is in the form of a moulded part, such as an injection moulded part in particular. The coating layer may cover the entire surface of the carrier or only part of it. For the avoidance of doubt it is to be understood that in the context of the present invention the coating layer is applied directly on the thermoplastic composition and there are no other layers between the coating layer and the thermoplastic composition. This may be achieved by IPL applying the coating on the carrier directly after it has been manufactured in a moulding equipment.

[0052] The thermoplastic composition preferably comprises at least, based on the weight of the thermoplastic composition, 75 wt.%, more preferably at least 85wt.%, more preferably at least 95 wt.%, even more preferably at least 98 wt.% of polycarbonate (A).

[0053] The thermoplastic composition may further comprises a polymer selected from the group consisting of poly-ethyleneterephthalate, poly-butyleneterephthalate, acrylonitrile- butadiene-styrene copolymer, styrene-acrylonitrile copolymer, optionally functionalised polypropylene, optionally functionalised polyethylene, optionally functionalised polyolefin elastomer, (meth)acrylic acid-polybutadiene core- shell copolymers, and mixtures of at least two of the foregoing. It is however preferred that the thermoplastic composition does not comprise any polymers other than polycarbonate and optionally polymers used for imparting flame retardant behaviour such as PTFE. The thermoplastic composition may comprise known additives such as colorants, fillers, reinforcing fillers or fibers, antioxidants, UV stabilisers, mold release agents, flame retardants and the like. It is however preferred that the thermoplastic composition does not comprises an anti-static agent as these may migrate to the surface of the moulded article and, depending also on the type of anti-static agent, may negatively affect the adhesion of the polyurethane.

[0054] The polycarbonate (A) may be a single type of polycarbonate or a mixture of at least two different types of polycarbonate. Further, the polycarbonate (A) may be a single grade or a mixture of different grades of polycarbonate of the same type, yet of different molecular weight, and / or different manufacturing method, and / or different amount of terminal hydroxyl content, and / or different endcap level and / or different amount of Fries content.

[0055] Preferably the first polycarbonate (A1) consists of one or more bisphenol A polycarbonate homopolymers. It is further preferred that the polycarbonate (A) consists of one or more bisphenol A polycarbonate homopolymers.

[0056] Commercially available polycarbonate, in particular bisphenol A polycarbonate homopolymers, may be obtained by two distinct manufacturing methods. IPL

[0057] In the so-called interfacial method one or more of a bisphenol, typically bisphenol A, is reacted with a carbonate source such as phosgene in a two phase liquid phase. Such two-phase system consists of an organic phase and an aqueous phase. The reaction typically takes place at the interface of the two phases where the growing polymer chains stay dissolved in the organic phase. The interfacial polymerisation is typically stopped by addition of an end-capping agent such as in particular phenolic end-capping agents like phenol, tert-butyl-phenol and para-cumyl-phenol. As a result, interfacial polycarbonate typically does not, or hardly, contain any phenolic hydroxyl groups, i.e. terminal hydroxyl groups. Notwithstanding the foregoing methods have been disclosed in the prior art to increase the amount of hydroxyl groups in interfacial polycarbonate. Such methods are disclosed for example in US 5,567,802 and 5,886,073 the contents of which are incorporated herein by reference.

[0058] In the so-called melt method, sometimes called melt transesterification method or melt polycondensation method, one or more of a bisphenol, typically bisphenol A, is reacted with a diarylcarbonate such as in particular diphenyl carbonate. This reaction is carried out in a molten phase consisting of the raw materials and optionally one or more of a catalyst. No solvent is used and the reaction medium is mono-phasic. In this method the bisphenol A reacts with the diphenyl carbonate thereby releasing phenol which is withdrawn from the reaction medium. Typically no endcapping agent is added in the melt process and accordingly the level of phenolic hydroxyl groups in melt polycarbonate is much higher as compared to interfacial polycarbonate. Apart from having a much higher phenolic hydroxyl group content melt polycarbonate is further distinct from interfacial polycarbonate in that it contains branching units as a result of Fries rearrangement reactions taking place at the relatively higher temperature at which the transesterification is carried out. The difference between “melt polycarbonate” and “interfacial polycarbonate” is well-known to a skilled person.

[0059] It is preferred that the polycarbonate (A) in the thermoplastic composition comprises at least 75 wt.%, preferably at least 90 wt.% more preferably at least 95 wt.% of the first polycarbonate (A1). More preferably the polycarbonate consists of the first polycarbonate (A1), meaning that other that the first polycarbonate no further polycarbonate is present in the polycarbonate. IPL

[0060] It is preferred that the polycarbonate (A) in the thermoplastic composition has a terminal hydroxyl content of at least 500ppm, preferably at least 700 ppm, determined in accordance with the method set out herein. For the avoidance of doubt the term "polycarbonate (A)" may include a mixture of polycarbonates.

[0061] The terminal hydroxyl content of the first polycarbonate (A1) and / or of the polycarbonate (A) may be at most 2500 ppm, preferably at most 2000 ppm, more preferably at most 1500 ppm or even more preferably at most 1250 ppm.

[0062] Preferably the first polycarbonate (A1) is a melt polycarbonate. More preferably the polycarbonate (A) of the thermoplastic composition consists of melt polycarbonate.

[0063] The polycarbonate (A) of the thermoplastic composition preferably comprises, essentially consists or consists of bisphenol A polycarbonate homopolymer(s).

[0064] The polycarbonate (A) preferably has a melt volume rate of from 5 - 40 cm3 / 10 min., preferably from 6 - 32 cm3 / 10 min. such as from 10 - 26 cm3 / 10 min., as measured in accordance with ISO 1133 (1.2 kg, 300°C). The first polycarbonate (A1) preferably has a melt volume rate of from 5 - 40 cm3 / 10 min., preferably from 10 - 32 cm3 / 10 min. as measured in accordance with ISO 1133 (1.2 kg, 300°C).

[0065] The polycarbonate (A) preferably does not consist of a linear polycarbonate, hereinafter referred to as PC-A, based on bisphenol A and further based on a mixture of 60 wt. % of a polycarbonate having a melt volume rate of 12 cm3 / 10 min as measured in accordance with ISO 1133:2012-03 at a temperature of 300°C and a load of 1.2 kg, and 40 wt.% of a polycarbonate having a melt volume rate of 30 cm3 / 10 min as measured in accordance with ISO 1133:2012-03 at a temperature of 250°C and a load of 1.2 kg, wherein the wt.% is based on the weight of the mixture.

[0066] The polycarbonate (A) preferably does not consist of a linear polycarbonate, hereinafter referred to as PC-B, based on bisphenol A and having a melt volume rate of 30 cm3 / 10 min as measured in accordance with ISO 1133:2012-03 at a temperature of 250°C and a load of 1.2 kg. IPL

[0067] The polycarbonate (A) preferably does not consist of a linear polycarbonate, hereinafter referred to as PC-C, based on bisphenol A and having a melt volume rate of 12 cm3 / 10 min as measured in accordance with ISO 1133:2012-03 at a temperature of 300°C and a load of 1.2 kg.

[0068] The polycarbonate (A) preferably does not consist of a linear polycarbonate (e.g. in powder form), hereinafter referred to as PC-D, based on bisphenol A and having a melt volume rate of 6 cm3 / 10 min as measured in accordance with ISO 1133:2012-03 at a temperature of 300°C and a load of 1 .2 kg.

[0069] The polycarbonate (A) preferably does not consist of linear polycarbonate based on bisphenol A having a melt volume rate of 6 cm3 / 10 min as measured in accordance with ISO 1133:2012-03 at a temperature of 300°C and a load of 1.2 kg, and linear polycarbonate based on bisphenol A having a melt volume rate of 12 cm3 / 10 min as measured in accordance with ISO 1133:2012-03 at a temperature of 300°C and a load of 1.2 kg.

[0070] The thermoplastic composition preferably does not consist of, based on the weight of the thermoplastic composition, 60 wt.% of PC-A and 40 wt.% PC-B, hereinafter referred to as TC-1.

[0071] The thermoplastic composition preferably does not consist of, based on the weight of the thermoplastic composition, 100 wt.% of PC-A, hereinafter referred to as TC-2.

[0072] The thermoplastic composition preferably does not consist of, based on the weight of the thermoplastic composition, 100 wt.% of PC-B, hereinafter referred to as TC-3

[0073] The thermoplastic composition preferably does not consist of, based on the weight of the thermoplastic composition, 100 wt.% of PC-C, hereinafter referred to as TC-4.

[0074] The thermoplastic composition preferably does not consist of, based on the weight of the thermoplastic composition, 95 wt.% of PC-A, 4.9 wt.% PC-D and 0.1 wt.% of glycerol monostearate (CAS 91052-47-0), hereinafter referred to as TC-5. IPL

[0075] Thermoplastic compositions TC-1 to TC-5, are specifically excluded when these are manufactured using a ZSK25 device (extrusion equipment) wherein the resin temperature was 260°C, the screw speed 225 rpm and the output between 17.5 and 20 kg / h.

[0076] The article is preferably not an article based on TC-1 , TC-2, TC-3, TC-4, and / or TC-5, preferably TC-1 , TC-2 and TC-5, and a polyurethane coating as manufactured in accordance with the Examples 1 ,2 and 5 and optionally Comparative Examples 3 and 4 of WO 2024 / 017706. The detailed description of how the articles according to these examples were made, as set out specifically on pages 41 - 45 of WO 2024 / 017706, including but not limited to the article dimensions, raw materials, processing conditions, measurement methods and measured properties are hereby specifically incorporated by reference. It is preferred that Examples 1 , 2, and 5 of this published patent application are specifically excluded.

[0077] The thermoplastic composition preferably does not comprise glycerol mono-stearate.

[0078] It is preferred that the polycarbonate (A) has an endcap level (EC%) of at most 85%, preferably from 25 - 85%, more preferably from 30 to 80%, 50 to 80% or 65 to 75%, wherein the endcap level is calculated with the following Formula I ppmOH X Mn

[0079] %EC = 100 - . 340000 wherein %EC is the endcap level, ppmOH is the content of terminal hydroxyl groups in parts per million by weight and Mn is the number average molecular weight of the polycarbonate based on polycarbonate standards and determined using gel permeation chromatography. The content of terminal hydroxyl groups can be determined using UV spectroscopy.

[0080] Thus, the endcap level is defined as the percentage of polycarbonate chain ends which are not hydroxyl groups. For example, a polycarbonate having and endcap level of 75 mol % means that the polycarbonate has 25 mol % of chain ends that are hydroxyl end groups, which typically result from the bisphenol A monomer. The other 75 mol % of end IPL groups do not contain a OH end group and may be phenolic or correspond to the end capping agent molecule(s).

[0081] In the embodiment where the first polycarbonate (A1) is a melt polycarbonate, the melt polycarbonate preferably has a Fries branching, or Fries content, of from 100 - 2000 ppm, such as 400 - 2000 ppm, preferably from 800 - 1700 ppm, more preferably from 1000 - 1500 ppm. The Fries content may be from 400 - 1200 ppm.

[0082] The coating layer in the article of the present invention is obtained by coating the carrier with a liquid coating comprising at least one poly isocyanate and at least one polyol. The resulting coating is a polyurethane coating. The poly-isocyanate is preferably a diisocyanate or a tri-isocyanate or a mixture of di- and tri-isocyanates. A single polyisocyanate or a mixture of different poly-isocyanates may be applied. Similarly a single polyol or a mixture of different polyols may be applied. Preferably the polyol is a diol, i.e. a compound having two hydroxyl functionalities.

[0083] Two component polyurethane coatings are known to the skilled person per se and in principle any available such coating system may be applied in the context of the present invention, the reason for this being that the present inventors consider that the concept underlying the invention is the interaction between the terminal hydroxyl groups from the polycarbonate and the isocyanate groups.

[0084] In the context of the invention the coating layer is not foamed, i.e. the coating layer is substantially free of voids provided it is acknowledged that in a typical wet coating process the (unintentional) formation of small voids or bubbles may not always be prevented.

[0085] The desired properties of the coating layer are obtained by selecting the appropriate poly-isocyanate and polyol, in addition to the isocyanate index. The isocyanate index is corresponds to the ratio of free isocyanate groups to isocyanate reactive groups such as hydroxyl groups from the polyol, amine and water, before reaction occurs. For the avoidance of doubt the terminal hydroxyl content of the polycarbonate is not taken into consideration for calculation of the isocyanate index. An isocyanate index of 1 indicates IPL that there are the same number of equivalents of isocyanate as there are the number of equivalents of hydroxyl groups, amine groups (if any) and water (if any). Typically no amine groups and water is present. Water has two equivalents per mole, a primary amine has two and a secondary amine has one. The isocyanate index is preferably from 0.90 to 1.2, more preferably from 0.95 to 1.1. In particular for polycarbonates having a high number of terminal hydroxyl groups a somewhat higher iso-cyanate index may be preferred compared to polycarbonate with a lower amount of terminal hydroxyl groups.

[0086] The coating layer, after curing, is preferably is at least 50 pm, preferably at least 100 pm, more preferable at least 250 pm and at most 5000 pm, preferably at most 4000 pm, more preferably at most 2500 pm.

[0087] Panel

[0088] The article of the present invention is preferably an automotive interior or exterior article.

[0089] The interior article may be comprised in or constitute a dashboard, instrument panel, console, display, functional surface trims, door trims and the like.

[0090] The exterior article may be comprised in or constitute a front, side or rear panel of a vehicle. The exterior article may also be comprised in or constitute a roof panel, engine hood or tailgate.

[0091] In particular, the article may be comprised in or constitute a vehicle front panel such as a front panel of a car, a truck, or a bus. In such an application the coating layer is exposed towards the driving direction, i.e. outwards. More preferably the article is comprised in or constitutes a front panel of an electrical vehicle such as an electrical car, truck or bus. For the avoidance of doubt, the present invention is directed at the use of the article as part of or as a front panel as described above.

[0092] The present invention further relates to a vehicle, such as a fossil fuel based car, truck or bus, an electrical car, truck or bus, or an electrical and fossil fuel based hybrid car, truck or bus comprising an article in accordance with the invention disclosed herein. IPL

[0093] In another preferred application the article is comprised in or constitutes the housing of electrical or electronic devices, such as mobile communication devices, in particular mobile phones, tablets or laptop computers, or the housing of appliances such as household equipment like vacuum cleaners, food processing equipment, coffee machines and the like.

[0094] Method

[0095] The present invention further relates to a method for the manufacture of the article disclosed herein, the method comprising the steps of i) injecting an amount of thermoplastic composition in a mould thereby forming said carrier by means of injection moulding, ii) cooling the injection moulded article, iii) applying a two-component polyurethane coating containing at least one polyisocyanate and at least one polyol directly on at least part of the injection moulded article, iii) curing the coating wherein said thermoplastic composition comprises polycarbonate and said polycarbonate comprises, based on the weight of the polycarbonate, at least 50 wt.% of a first polycarbonate having a terminal hydroxyl content of at least 500ppm, preferably at least 700 ppm.

[0096] It is preferred that the cooled injection moulded article of step ii) is transferred to a second cavity and that at least step iii) is carried out in that second cavity.

[0097] It is further preferred that prior to application of the coating in step iii) at least a part of the to be coated surface of the injection moulded article is subjected to a corona or flame treatment in order to further increase the amount of hydroxyl groups on the surface of the injection moulded part.

[0098] Typically the method is carried out in a process known as a flood coating or in-mould coating process. In such a process the carrier is manufactured via injection moulding in an injection moulding equipment. After injection of the thermoplastic composition the so formed carrier is cooled until it has sufficiently solidified. Then, while the carrier is still in the mould a coating is injected to coat at least one side, or part thereof, of the carrier. This may be carried out in the same mould or preferably in a second cavity as indicated IPL above. The coating is then cured, typically under pressure, until the carrier can be removed from the mould. After the carrier is taken from the mould the coating may or may not yet be fully cured. The present invention will now be further elucidated based on the following non-limiting examples.

[0099] Measurement methods IPL IPL IPL

[0100] IPL

[0101] Polycarbonate materials

[0102] Table 1

[0103] All polycarbonates PC1 - PC5 are bisphenol A polycarbonate homopolymers.

[0104] Coating adhesion

[0105] The polycarbonates PC1 - PC5 were molded into plaques with a thickness of 3 mm after which a 2-component polyurethane coating was applied. The polyurethane coating was Puroclear 3351 iT available from the company Ruhl. This coating is a two-component polyurethane coating comprising a polyester polyol and an isocyanate wherein the weight ratio of polyol to isocyanate is 100: 230. The cured coating had a thickness of 0.6 mm.

[0106] Next the so obtained coated articles were subjected to a so-called Positest in accordance with the standard ISO 4624 Method B (3rdEdition, 2016) using a Dolly with a diameter of 20mm and an applied tensile stress speed of 0,7 MPa / s. The adhesive that was used was LORD 406E / 17 acrylic adhesive. The tests were carried out room temperature of 23 + / - 2 °C and a relative humidity of 50 + / - 5%. The Positest, as known to the skilled person, is used to test the adhesion of a coating to a substrate. IPL

[0107] The Positest was carried out on the coated articles after the coating was fully cured, which typically meant after about 24 hours, but before the samples were aged. Another Positest was carried out on samples obtained by subjecting the coated and fully cured articles to an aging cycle in accordance with the BMW PR 303.5b climate test. This climate test comprises exposing, in cycles, the articles to temperatures within a range of -30°C to 80 °C cycles and at different relative humidity conditions. The total duration of the cycles is 240 hours. The BMW PR 303.5b climate test is well-known to the skilled person.

[0108] The results of the test are shown in Table 2

[0109] Table 2

[0110] The results as presented in Table 2 show that polycarbonate articles having a relatively high amount of terminal hydroxyl content show an improved adhesion to 2 component polyurethane coatings based on isocyanate and polyol monomers. The positive effect is see both before and after aging. The reason for the difference in Positest results after aging for PC4 and PC5 is not entirely clear to the present inventors. A possible explanation might relate to the difference in Fries content for these polycarbonates.

[0111] In a further example several polycarbonate plaques were provided with a 2-component polyurethane coating based on isocyanate and polyol monomers. The coating was Puroclear 3098-4IT commercially available from the company Ruhl and was applied such that the thickness of the coating layer after curing was 0.6mm. After curing the peel strength of the coating was measured in accordance with ASTM D3167. The results are presented in Table 3 below IPL

[0112] Table 3

[0113] The present inventors found that when interfacial polycarbonates were uses, with no or negligible terminal hydroxyl groups, no peel strength could be determined.

[0114] The data in this table show that a lower endcap level (EC%) and accordingly a higher content of terminal hydroxyl groups leads to an increased peel strength. The data further suggests that below a content of terminal hydroxy groups of about 700ppm the cooling time of the injection moulded sample before being coated is of less relevance. The reason for this effect is not entirely clear. It may also be appreciated that the coating adhesion is less when the polycarbonate moulding is cooled for a longer time.

[0115] The present inventors also tried to perform the peel test using polycarbonate manufactured with an interfacial process, i.e. a polycarbonate which is fully end-capped. The coating came off very easily and as a result no peel strength could be measured.

[0116] Apart from the improved adhesion the present inventors also found that, compared to polycarbonate moldings provided with a hard-coat or UV cured coatings, such as traditional acrylic or siloxane coatings, the impact properties of the articles in accordance with the invention were improved. This finding is based on the testing of several samples with a so called "drop tower test-protocol" in accordance with ISO 6603-A, where the coated side was the side of the impact. In particular the present inventors found that the impact of 3.6mm thick polycarbonate panels prepared from melt polycarbonate with a MVR of 21 cm3 / 10 min and endcap level of 75% and a Fries content of 1050 ppm coated IPL with the same coating as per examples E1 - E3 showed ductile failure at most in the impact test. No brittle failures were observed. To the contrary, comparable articles provided with a hard-coat coating layer or with a UV cured coating layer showed only brittle failures. This aspect is of high importance for use of the coated articles as front panels for (electrical) vehicles.

[0117] Raman spectroscopy was carried out in accordance with the method set out herein on the coated plaques of CE1 (PC-1 a, PC-1 b), E1 (PC-3a, PC-3b) and E2 (PC-4a, PC-4b). Further plaques using PC-4c, PC-4d were made, yet the temperature of the mold carrier prior to coating, corresponding to the mold temperature applied during injection moulding of the plaque, was about 20 °C lower than the temperature applied for the manufacture of the plaques in accordance with E2. The pairs a / b and c / d referto duplicates, i.e. every sample was measured at two positions along the coating-carrier interface.

[0118] Figure 1 shows the overall result of the Raman spectroscopy measurements after having shifted all curves so that these share the 50% concentration position. The position is plotted on the horizontal axis whereas the vertical axis shows the concentration of the polyurethane.

[0119] Figure 2 shows an enlarged part of the curve of Figure 1 on the side of the polyurethane coating layer. From this graph the transition layer thickness and the transition slope were determined. It is observed that upon increasing terminal hydroxyl content the absolute value of the transition slope increases and the transition layer thickness decreases. It is also observed, based on a comparison of the curves PC-4a / b and PC-4c / d, that a lowering of the temperature of the to-be-coated carrier results in a reduction in transition slope. This seems to confirm the concept that diffusion of polycarbonate from the carrier into the coating is influenced not only by the chemistry of the polycarbonate (i.e. the terminal hydroxyl content), but also by the actual process to manufacture the article. Put differently, the present inventors consider that the shape of the transition layer and all features derived therefrom, like the thickness and other features as defined herein, depend not only on the chemistry as applied, i.e. the amount of hydroxyl groups of the polycarbonate and the components of the polyurethane coating, but also on the processing conditions. At present, the inventors consider that in particular the temperature during the actual coating process (and also the curing of the coating) plays IPL an important role. Due to the difficulty in performing meaningfull measurements combined with the applied chemistry it is however not possible to express this finding in any way other than as disclosed herein. That is to say, the thickness of the transition layer, as well as the absense of the minimum in the curve plotting an atomic force microscopy signal as a function of the position of an atomic force microscopy measurement probe over a straight line perpendicular to the transition layer, said position ranging from a position in the carrier the carrier to a position in the coating layer, depend to a large extent, but not solely, on the amount of hydroxyl groups of the polycarbonate. Accordingly the present inventors consider that there is no direct and unambiguous relation between the exact value for the thickness of transition layer as disclosed herein and the amount of hydroxyl groups of the polycarbonate.

[0120] Samples of CE1 , E1 and E2 were also measured using atomic force microscopy. Two areas along the coating-carrier interface were measured. All samples were measured with the carrier (polycarbonate, “PC”) on the left side and the coating “PU” on the right side.

[0121] Figure 3a shows an image of measurements of CE1 , whereas Figure 3b shows a plot of the AFM signal vs the position of the measurement probe. In Figure 3a the left side corresponds to the carrier, indicated with “PC” and the right side corresponds to the coating, indicated with “PU”. The dotted line is an indication where the 100% polyurethane coating starts / ends. To the left of the dotted line areas with lighter color can be observed. Figure 3a also shows a rectangular area which indicates the are in which the actual AFM measurements were performed.

[0122] Dotted lines and “PU” and “PC” indications are omitted for the other measurements but are located at the same / similar position.

[0123] In Figure 3b the value on the vertical axis is a numerical average of the AFM signal as measured in 100 line scans performed in the area indicated in the Figure 3a whereas on the horizontal axis the position is plotted. The encircled portion of the graph shows a minimum and the present inventors consider this as an indication of poor coating adhesion. IPL

[0124] In Figures 3c and 3d another area of example CE1 was studied using atomic force microscopy. The results are similar to those in Figures 3a and 3b.

[0125] Measurements on E1 are shown in Figures 4a- 4d in a similar way as done for Example CE1. While some line scans did still show a minimum in the AFM response curve, on average there was a smooth transition of the AFM signal from the polycarbonate to the polyurethane and no minimum in de curve was observed.

[0126] Measurements on E2 are shown in Figures 5a- 5d in a similar way as done for Example CE1. No minimum in de AFM curve was observed. Moreover, the typical “white areas” such as found in particular in CE1 was not found.

[0127] From the atomic force measurements the present inventors conclude, without however willing to be strictly bound to it consider that the absence of a minimum in the AFM curve is indicative for a good adhesion between the carrier and the coating. In particular the AFM curves for PC4 (i.e. E2) show a gradual transition of the AFM signal on the side of the polyurethane coating when transitioning to the polycarbonate. The example based on CE1 does not show such a gradual transition and clearly shows a minimum in the said curve indicating a local change in material properties which is assumed to correspond to poor adhesion.

Claims

24POLY0092-PCT 29 IPLC L A I M S1 . Article comprising a carrier provided at least in part with a coating layer, wherein- said carrier comprises or consists of a thermoplastic composition, said thermoplastic composition comprising polycarbonate (A),- said coating layer is applied directly on said carrier and comprises or consists of polyurethane obtained by reacting at least one poly-isocyanate and at least one polyol,- said polycarbonate (A) comprises, based on the weight of the polycarbonate, at least 50 wt.% of a first polycarbonate (A1) having a terminal hydroxyl content of at least 500ppm, preferably at least 700 ppm, determined in accordance with the method set out in the description,- the article further comprises a transition layer having a thickness, located between the coating layer and the carrier, wherein said transition layer is obtained by the application of said coating to said carrier,- the thickness of the transition layer is lower compared to a transition layer obtained under identical article manufacturing conditions and by application of an identical coating and by application of an otherwise identical thermoplastic composition except that the first polycarbonate (A1) has a terminal hydroxyl content such that the terminal hydroxyl content of the polycarbonate (A) is less than 250 ppm, preferably at most 150ppm, wherein the thickness of the transition layer is determined in accordance with the method set out in the description and defined as the distance wherein the concentration of polyurethane transitions from 90% to 50%.

2. The article of claim 1 wherein the thickness of the transition layer is at most 1.0 pm, preferably at most 0.8 pm, preferably at most 0.6 pm.

3. Article comprising a carrier provided at least in part with a coating layer, wherein- said carrier comprises or consists of a thermoplastic composition, said thermoplastic composition comprising polycarbonate (A),- said coating layer is applied directly on said carrier and comprises or consists of polyurethane obtained by reacting at least one poly-isocyanate and at least one polyol,24POLY0092-PCT 30 IPL- said polycarbonate (A) comprises, based on the weight of the polycarbonate (A), at least 50 wt.% of a first polycarbonate (A1) having a terminal hydroxyl content of at least 500ppm, preferably at least 700 ppm, determined in accordance with the method said out in the description,- the article further comprises a transition layer having a thickness, located between the coating layer and the carrier, wherein said transition layer is obtained by the application of said coating to said carrier,- wherein, for at least a portion of the obtained coated carrier, a curve plotting an atomic force microscopy signal as a function of the position of an atomic force microscopy measurement probe over a straight line perpendicular to the transition layer, said position ranging from a position in the carrier the carrier to a position in the coating layer, does not show a minimum in the transition layer at a position close to the coating layer, wherein the atomic force microscopy is carried out in accordance with the method as set out in the description.

4. The article of claim 3, wherein the article is an article according to claim 1 or 2.

5. The article of any one or more of claims 1 - 4 wherein the polycarbonate (A) comprises at least 75 wt.%, preferably at least 90 wt.% more preferably at least 95 wt.% of said first polycarbonate (A1).

6. The article of any one or more of claims 1 - 5 wherein the first polycarbonate (A1) is a melt polycarbonate.

7. The article of any one or more of claims 1 - 6 wherein the polycarbonate (A) has a melt volume rate of from 5 - 40 cm3 / 10 min. as measured in accordance with ISO 1133 (1.2 kg, 300°C).

8. The article of any one or more of claims 1 - 7 wherein the thermoplastic composition comprises at least 95 wt.%, preferably at least 98 wt.% of polycarbonate (A) based on the weight of the thermoplastic composition.24POLY0092-PCT 31 IPL9. The article of any one or more of claims 1 - 8 wherein the polycarbonate (A) has an endcap level (EC%) of at most 85%, as calculated with Formula I / ppmOH X Mn%EC = 100 - \ 340000wherein %EC is the endcap level, ppmOH is the terminal hydroxyl content in parts per million by weight and Mn is the number average molecular weight of the polycarbonate (A) based on polycarbonate standards and determined using gel permeation chromatography.

10. The article of any one or more of claim 1 - 9 wherein said thermoplastic composition comprises a polymer selected from the group consisting of polyethyleneterephthalate, poly-butyleneterephthalate, acrylonitrile-butadiene-styrene copolymer, styrene-acrylonitrile copolymer, optionally functionalised polypropylene, optionally functionalised polyethylene, optionally functionalised polyolefin elastomer, (meth)acrylic acid-polybutadiene core- shell copolymers, and mixtures of at least two of the foregoing.

11. The article of any one or more of claims 1 - 10 wherein the coating thickness, determined after curing, is at least 50 pm, preferably at least 100 pm, more preferable at least 250 pm and at most 5000 pm, preferably at most 4000 pm, more preferably at most 2500 pm.

12. The article of any one or more of claims 1 - 11 wherein the article is:- a vehicle interior article comprised in or constituting a dashboard, instrument panel, console, display, functional surface trims or door trims, or- a vehicle exterior article comprised in or constituting a front, side or rear panel of a vehicle, optionally a roof panel, engine hood or tailgate, or- comprised in or constituting the housing of electrical or electronic devices, preferably mobile communication devices.24POLY0092-PCT 32 IPL13. A front panel of an electrical vehicle comprising or consisting of the article of any one or more of claims 1 - 11.

14. Vehicle, preferably an electrical vehicle, comprising a front panel comprising or consisting of the article of any one or more of claims 1 - 11 , said front panel being a panel facing the forward direction of the vehicle.

15. Method for the manufacture of the article of any one or more of claims 1 - 12 comprising the steps of iii) injecting an amount of thermoplastic composition in a mould thereby forming said carrier by means of injection moulding, ii) cooling the injection moulded article, iii) applying a two-component polyurethane coating containing at least one polyisocyanate and at least one polyol directly on at least part of the injection moulded article, iii) curing the coating wherein, said thermoplastic composition comprises polycarbonate and said polycarbonate comprises, based on the weight of the polycarbonate, at least 50 wt.% of a first polycarbonate having a terminal hydroxyl content of at least 500ppm, preferably at least 700 ppm.

16. The method of claim 15 further comprising the step of transferring the cooled injection moulded article of step ii) to a second cavity prior to application of the coating in step iii).

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