Coated article

Abstract

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

Description

Technical Field

[0001] This invention relates to a coated article. More specifically, this invention relates to an article comprising a carrier and a polyurethane coating applied directly to at least a portion of the carrier, wherein the carrier comprises or is composed of a thermoplastic composition containing polycarbonate. Background Technology

[0002] Polycarbonate or polycarbonate-based compositions are widely known due to their use in automotive applications (exterior and interior). Protective coatings are typically applied to protect such articles from scratches, weathering, or chemicals. For example, headlight covers made of polycarbonate often have a hard coating several micrometers thick. These are typically acrylic or silicone-based coatings.

[0003] In the automotive industry, new requirements and standards are being developed regarding the impact resistance of the front panels of automobiles (especially electric vehicles). These requirements stipulate that, in the event of an accident (i.e., impact with a person or animal), front components (such as the front panel) should cause minimal harm to the human or animal. This can be achieved by avoiding the formation of sharp and / or brittle segments in the corresponding component due to impact. Similarly, the front component should not be damaged or destroyed by impact. To some extent, these requirements are addressed by the actual design of the panel or component, but they are also influenced at least in part by the nature of the coated component or panel. Therefore, it is preferable that the component or panel exhibits, at most, ductile impact failure rather than brittle impact failure.

[0004] In addition to mechanical requirements, there are also aesthetic requirements, namely, that the coating adheres fully to the substrate and does not delaminate over time. This requirement is particularly important for automotive interior applications such as trim bezels (e.g., trim bezels integrated into the console, dashboard, or door panels).

[0005] Therefore, the object of the present invention is to provide a coated article having sufficient or improved coating adhesion and / or wherein any negative impact of the coating on the mechanical properties of the carrier (i.e., the uncoated article) is minimized or even improved.

[0006] The interaction between polyurethane and polycarbonate is disclosed in the prior art.

[0007] US2019 / 0232621 discloses a multilayer article comprising: i) a dense substrate layer comprising a polymer composition, wherein the polymer composition is a blend comprising a polycarbonate polymer, a toughening component, and a filler, the toughening component comprising a rubber-modified monovinyl aromatic thermoplastic containing an impact modifier, and the filler comprising wollastonite; and ii) a polyurethane overlay layer directly bonded to the dense substrate layer; wherein the amount of polyester in the polymer composition is about zero or less than about 5% by weight. According to this document, a substrate formed from a combination of ABS (especially mass ABS) with a specific maximum amount of polycarbonate and wollastonite filler has been found to result in improved adhesion properties (initial adhesion and adhesion after weathering) when overmolded or painted with a polyurethane layer.

[0008] US2019 / 0153218 discloses a composite component comprising a) a carrier consisting of a thermoplastic composition comprising the following components:

[0009] A) 55-75 parts by weight of at least one polymer selected from aromatic polycarbonate and aromatic polyester carbonate;

[0010] B) 25-45 parts by weight of at least one blend, said blend 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

[0011] C) 0.1-20.0 parts by weight (based on the sum of components A and B in each case) of at least one polymer additive, wherein the polybutadiene content is 10-20% by weight based on the sum of components A and B.

[0012] The total content of butadiene-free vinyl (co)polymer from component B, based on the sum of the weight parts of components A and B, is 12-23% by weight, and the sum of the weight parts of components A and B in the polycarbonate composition is normalized to 100; and b) at least one polyurethane layer selected from coatings, foams and tight skins, said polyurethane layer comprising at least one polyisocyanate component; at 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.

[0013] US 2002 / 01670177 discloses a polycarbonate composition comprising (A) an aromatic polycarbonate and / or a polyester-carbonate, (B) a graft polymer, and (C) a copolymer of styrene and at least one monomer containing at least one carboxyl group, said copolymer having a weight-average molecular weight M equal to or greater than 10,500 g / mol. According to this document, the addition of copolymer (C) has been found to achieve a significant improvement in foam adhesion, particularly relative to polyurethane foam adhesion.

[0014] US 5,688,837 discloses a method for adhering polyurethane foam to polycarbonate, the method comprising: a) providing nucleophilic reactive radicals on a polycarbonate surface; b) preparing a polyurethane mixture comprising at least one polyol and at least one diisocyanate, wherein the polyurethane mixture exhibits an isocyanate index greater than 82; and c) foaming the polyurethane mixture on the polycarbonate surface. According to this document, the polycarbonate must have at least one type of nucleophilic reactive radical on its surface. Nucleophilic reactive radicals can be provided by processing during the manufacture of the polycarbonate. Nucleophilic reactive radicals can be formed on the polycarbonate during polymerization. For example, bisphenol A polycarbonate prepared by melt transesterification contains hydroxyl nucleophilic reactive radicals.

[0015] US 2011 / 0027575 discloses a method for producing a composite material, the method comprising (i) producing a foamed polycarbonate molding composition by injection molding using chemical and / or physical foaming techniques, and (ii) applying a polyurethane reaction system on top of the polycarbonate molding composition and allowing it to cure.

[0016] US 2006 / 0151911 discloses an in-mold coating method comprising (i) obtaining a mold having at least two chambers, (ii) molding a thermoplastic substrate in a first chamber, (iii) introducing the substrate into a second chamber, and (iv) coating the substrate with a varnish, the coating being performed under enhanced pressure and the varnish being cured. The method disclosed in this document is said to be suitable for varnish layer thicknesses in the range of 0.01-3 mm.

[0017] WO2024 / 017706 describes a method for producing a composite component with improved interlayer bonding, the component comprising a carrier containing polycarbonate and at least one layer of polyurethane in direct contact with the carrier. The invention also relates to composite components with improved interlayer bonding, and the use of polycarbonate with a defined OH content as a carrier material in the production of composite components with improved interlayer bonding.

[0018] EP 4309865 describes a method for producing a composite component with improved interlayer bonding, the component comprising a carrier containing polycarbonate and at least one layer of polyurethane in direct contact with the carrier. The present invention also relates to composite components with improved interlayer bonding, and the use of compositions comprising polycarbonate and specific hydroxyl components as carrier materials in the production of composite components with improved interlayer bonding.

[0019] Although the prior art generally discloses articles based on materials containing polycarbonate that can be incorporated with polyurethane coatings or foam layers, the prior art does not mention the use of such materials in certain automotive applications (particularly for the front panels of electric vehicles). Summary of the Invention

[0020] In this regard, the present invention generally relates to an article comprising a carrier, said carrier being at least partially provided with a coating, wherein

[0021] - The carrier comprises or is composed of a thermoplastic composition, wherein the thermoplastic composition contains polycarbonate.

[0022] - The coating is applied directly to the carrier and comprises or consists of a polyurethane obtained by reacting at least one diisocyanate or triisocyanate with at least one polyol.

[0023] - The polycarbonate comprises at least 50 wt% of a first polycarbonate based on the weight of the polycarbonate, the first polycarbonate having a terminal hydroxyl content of at least 500 ppm, preferably at least 700 ppm, as determined according to the methods described herein.

[0024] Preferably, the present invention relates to an article comprising a carrier, wherein the carrier is at least partially provided with a coating, wherein

[0025] - The carrier comprises or is composed of a thermoplastic composition, wherein the thermoplastic composition comprises polycarbonate.

[0026] - The coating is applied directly to the carrier and comprises or consists of a polyurethane obtained by reacting at least one polyisocyanate and at least one polyol.

[0027] The polycarbonate comprises at least 50 wt% of a first polycarbonate based on the weight of the polycarbonate, the first polycarbonate having a terminal hydroxyl content of at least 500 ppm, preferably at least 700 ppm, the terminal hydroxyl content being determined according to the methods described herein.

[0028] in,

[0029] - Articles are internal articles of a vehicle that are contained in or constitute dashboards, instrument panels, consoles, displays, functional surface trims, or door trims, or

[0030] - An article is an external article of a vehicle that is included in or constitutes the front panel, side panel or rear panel of a vehicle.

[0031] Preferably, the invention also relates to the use of an article comprising a carrier as an internal or external article of a vehicle, said carrier being at least partially provided with a coating, wherein

[0032] - The carrier comprises or is composed of a thermoplastic composition, wherein the thermoplastic composition comprises polycarbonate.

[0033] - The coating is applied directly to the carrier and comprises or consists of a polyurethane obtained by reacting at least one polyisocyanate and at least one polyol.

[0034] - The polycarbonate comprises at least 50 wt% of a first polycarbonate based on the weight of the polycarbonate, the first polycarbonate having a terminal hydroxyl content of at least 500 ppm, preferably at least 700 ppm, as determined by the method set forth in the specification, wherein the vehicle interior articles are included in or constitute a dashboard, instrument panel, console, display, functional surface trim or door trim, and the vehicle exterior articles are included in or constitute a front panel, side panel or rear panel of the vehicle.

[0035] Preferably, the present invention relates to an article comprising a carrier, wherein the carrier is at least partially provided with a coating, wherein

[0036] - The carrier comprises or is composed of a thermoplastic composition, wherein the thermoplastic composition comprises polycarbonate.

[0037] - The coating is applied directly to the carrier and comprises or consists of a polyurethane obtained by reacting at least one diisocyanate or triisocyanate with at least one polyol.

[0038] - The polycarbonate comprises at least 50 wt% of a first polycarbonate based on the weight of the polycarbonate, the first polycarbonate having a terminal hydroxyl content of at least 500 ppm, preferably at least 700 ppm, determined according to the methods described herein, wherein the polycarbonate has a capping level of up to 85% (EC%), calculated as using Formula I:

[0039]

[0040] Where %EC is the end-capping level, ppmOH is the content of terminal hydroxyl groups in parts per million by weight, and Mn is the number-average molecular weight of polycarbonate determined by gel permeation chromatography based on polycarbonate standards.

[0041] Preferably, the present invention relates to an article comprising a carrier, wherein the carrier is at least partially provided with a coating, wherein

[0042] - The carrier comprises or is composed of a thermoplastic composition, wherein the thermoplastic composition comprises polycarbonate.

[0043] - The coating is applied directly to the carrier and comprises or consists of a polyurethane obtained by reacting at least one diisocyanate or triisocyanate with at least one polyol.

[0044] - The polycarbonate comprises at least 50 wt% of a first polycarbonate based on the weight of the polycarbonate, the first polycarbonate having a terminal hydroxyl content of at least 500 ppm, preferably at least 700 ppm, determined according to the methods described herein, wherein the polycarbonate has a 5-40 cm³ content as measured according to ISO 1133 (1.2 kg, 300 °C). 3 Melt volume rate per 10 min.

[0045] Preferably, the present invention relates to an article comprising a carrier, wherein the carrier is at least partially provided with a coating, wherein

[0046] - The carrier comprises or is composed of a thermoplastic composition, wherein the thermoplastic composition comprises polycarbonate.

[0047] - The coating is applied directly to the carrier and comprises or consists of a polyurethane obtained by reacting at least one diisocyanate or triisocyanate with at least one polyol.

[0048] - The polycarbonate comprises at least 50 wt% of a first polycarbonate based on the weight of the polycarbonate, the first polycarbonate having a terminal hydroxyl content of at least 500 ppm, preferably at least 700 ppm, the terminal hydroxyl content being determined according to the methods set forth herein, and wherein the thermoplastic composition comprises a polymer selected from: polyethylene terephthalate, polybutylene terephthalate, acrylonitrile-butadiene-styrene copolymer, styrene-acrylonitrile copolymer, optionally functionalized polypropylene, optionally functionalized polyethylene, optionally functionalized polyolefin elastomer, (meth)acrylic acid-polybutadiene core-shell copolymer, and mixtures of at least two of the foregoing.

[0049] Without being constrained, the inventors believe that an improved coating, namely improved coating adhesion, is obtained because a portion of the isocyanate groups in the two-component polyurethane coating reacts with naturally occurring phenolic hydroxyl groups on the molten polycarbonate chains. Polyurethane chains can be grown from these bonded isocyanate groups to form at least partially cross-linked coatings that are chemically bonded to the carrier.

[0050] As mentioned in the context of this invention, the carrier comprises or is composed of a thermoplastic composition containing polycarbonate, wherein the polycarbonate contains at least 50 wt% of a first polycarbonate having a terminal hydroxyl content of at least 500 ppm, preferably at least 700 ppm, based on the weight of the polycarbonate.

[0051] Carriers are typically obtained by molding a thermoplastic composition, such as by injection molding, extrusion molding, or compression molding, preferably by injection molding. Preferably, the carrier consists of a thermoplastic composition. However, the carrier may also include additional components, such as compositions other than the thermoplastic composition that come into contact with portions of the carrier made of the thermoplastic composition. For example, the carrier may be molded from two compositions, wherein a first surface portion of the carrier consists of the thermoplastic composition and the other surface portion does not. In the context of such embodiments, a coating is applied at least partially to the surface of the carrier composed of the thermoplastic composition. However, generally and in preferred embodiments, the carrier consists of a thermoplastic composition and is in the form of a molded part, for example, particularly an injection-molded part. The coating may cover the entire surface of the carrier or only a portion thereof. To avoid confusion, it should be understood that, in the context of the present invention, the coating is applied directly to the thermoplastic composition, and there is no other layer between the coating and the thermoplastic composition. This can be achieved by applying the coating directly to the carrier after it has already been manufactured in a molding apparatus.

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

[0053] The thermoplastic composition may additionally comprise polymers selected from: polyethylene terephthalate, polybutylene terephthalate, acrylonitrile-butadiene-styrene copolymer, styrene-acrylonitrile copolymer, optionally functionalized polypropylene, optionally functionalized polyethylene, optionally functionalized polyolefin elastomer, (meth)acrylic acid-polybutadiene core-shell copolymer, and mixtures of at least two of the foregoing. However, it is preferred that the thermoplastic composition does not contain any polymers other than polycarbonate, and optionally polymers such as PTFE for imparting flame-retardant behavior. The thermoplastic composition may contain known additives such as colorants, fillers, reinforcing fillers or fibers, antioxidants, UV stabilizers, release agents, flame retardants, etc. However, it is preferred that the thermoplastic composition does not contain antistatic agents, as they may migrate to the surface of the molded article and, depending on the type of antistatic agent, may negatively affect the adhesion of the polyurethane.

[0054] Polycarbonate can be a single type of polycarbonate or a mixture of at least two different types of polycarbonate. Furthermore, polycarbonate can be a single grade, or a mixture of different grades of the same type of polycarbonate but with different molecular weights, and / or different manufacturing methods, and / or different terminal hydroxyl content, and / or different end-capping levels, and / or different Fries content.

[0055] Preferably, the first polycarbonate is composed of one or more bisphenol A polycarbonate homopolymers. More preferably, the polycarbonate is composed of one or more bisphenol A polycarbonate homopolymers.

[0056] Commercially available polycarbonates, especially bisphenol A polycarbonate homopolymers, can be obtained through two different manufacturing methods.

[0057] In the so-called interfacial method, one or more bisphenols, typically bisphenol A, are reacted with a carbonate source such as phosgene in a two-phase liquid system. This two-phase system consists of an organic phase and an aqueous phase. The reaction typically occurs at the interface between the two phases, where the grown polymer chains remain dissolved in the organic phase. Interfacial polymerization is typically stopped by adding a capping agent, such as, in particular, phenolic capping agents, such as phenol, tert-butylphenol, and p-cumylphenol. As a result, the interfacial polycarbonate typically contains little or no phenolic hydroxyl groups, i.e., terminal hydroxyl groups. Nevertheless, the aforementioned method has been disclosed in the prior art to increase the amount of hydroxyl groups in the 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 process, sometimes called melt transesterification or melt polycondensation, one or more bisphenols, typically bisphenol A, are reacted with diaryl carbonates, such as, in particular, diphenyl carbonate. The reaction takes place in a molten phase consisting of the raw materials and optionally one or more catalysts. No solvent is used, and the reaction medium is single-phase. In this method, bisphenol A reacts with diphenyl carbonate, thereby releasing phenol, which is then removed from the reaction medium. Typically, no end-capping agents are added in the melt process, resulting in a much higher level of phenolic hydroxyl groups in molten polycarbonates compared to interfacial polycarbonates. Besides having a much higher phenolic hydroxyl content, molten polycarbonates also differ from interfacial polycarbonates in that they contain branched units due to the Fries rearrangement reaction that occurs at the relatively higher temperatures during transesterification. The distinction between "molten polycarbonate" and "interfacial polycarbonate" is well known to those skilled in the art.

[0059] Preferably, the polycarbonate in the thermoplastic composition comprises at least 75 wt%, more preferably at least 90 wt%, and more preferably at least 95 wt% of a first polycarbonate. More preferably, the polycarbonate consists of a first polycarbonate, meaning that no other polycarbonate is present in the polycarbonate besides the first polycarbonate.

[0060] Preferably, the polycarbonate in the thermoplastic composition has a terminal hydroxyl content of at least 500 ppm, preferably at least 700 ppm, as determined according to the methods described herein. For the avoidance of confusion, the term "polycarbonate" may include mixtures of polycarbonates.

[0061] The terminal hydroxyl content of the first polycarbonate and / or polycarbonate may be up to 2,500 ppm, preferably up to 2,000 ppm, more preferably up to 1,500 ppm, or even more preferably up to 1,250 ppm.

[0062] Preferably, the first polycarbonate is molten polycarbonate. More preferably, the polycarbonate of the thermoplastic composition is composed of molten polycarbonate.

[0063] The polycarbonate of the thermoplastic composition preferably comprises, or is substantially composed of, or is composed of, bisphenol A polycarbonate homopolymer.

[0064] Polycarbonate preferably has a thickness of 5-40 cm. 3 / 10min, preferably 6-32cm 3 / 10min, for example, 10-26cm 3 The melt volume rate was measured per 10 min according to ISO 1133 (1.2 kg, 300 °C). The first polycarbonate preferably has a melt volume ratio of 5-40 cm⁻¹. 3 / 10min, preferably 10-32cm 3Melt volume rate per 10 min, determined according to ISO 1133 (1.2 kg, 300 °C).

[0065] The polycarbonate is preferably not composed of linear polycarbonate, hereinafter referred to as PC-A, which is based on bisphenol A and also on 60 wt% of a melt volume fraction of 12 cm⁻¹ determined according to ISO 1133:2012-03 at a temperature of 300°C and a load of 1.2 kg. 3 The melt volumetric rate of polycarbonate and 40 wt% of [unspecified substance] measured according to ISO 1133:2012-03 at 250°C and a load of 1.2 kg was 30 cm⁻¹. 3 A mixture of polycarbonate per 10 min, where wt% is based on the weight of the mixture.

[0066] Polycarbonate is preferably not based on bisphenol A and has a thickness of 30 cm. 3 Linear polycarbonate (hereinafter referred to as PC-B) composition with a melt volume rate of / 10min as determined according to ISO 1133:2012-03 at a temperature of 250°C and a load of 1.2kg.

[0067] Polycarbonate is preferably not based on bisphenol A and has a thickness of 12 cm. 3 Linear polycarbonate (hereinafter referred to as PC-C) composition with a melt volume rate of / 10min as determined according to ISO 1133:2012-03 at a temperature of 300°C and a load of 1.2kg.

[0068] Polycarbonate is preferably not based on bisphenol A and has a 6cm thickness. 3 Linear polycarbonate (e.g., in powder form) (hereinafter referred to as PC-D) composition with a melt volume rate of / 10 min as determined according to ISO 1133:2012-03 at a temperature of 300 °C and a load of 1.2 kg.

[0069] Polycarbonate is preferably not composed of: a melt volumetric velocity of 6 cm⁻¹ as determined according to ISO 1133:2012-03 at a temperature of 300°C and a load of 1.2 kg. 3 / 10min for bisphenol A-based linear polycarbonate, and a melt volumetric rate of 12cm³ / min as determined according to ISO 1133:2012-03 at 300°C and a load of 1.2kg. 3 / 10min of bisphenol A-based linear polycarbonate.

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

[0071] The thermoplastic composition is preferably not composed of 100 wt% PC-A (hereinafter referred to as TC-2) based on the weight of the thermoplastic composition.

[0072] The thermoplastic composition is preferably not composed of 100 wt% PC-B (hereinafter referred to as TC-3) based on the weight of the thermoplastic composition.

[0073] The thermoplastic composition is preferably not composed of 100 wt% PC-C (hereinafter referred to as TC-4) based on the weight of the thermoplastic composition.

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

[0075] Thermoplastic compositions TC-1 to TC-5 are specifically excluded when they are manufactured using ZSK25 equipment (extrusion unit) with a resin temperature of 260°C, a screw speed of 225 rpm, and a production rate of 17.5 to 20 kg / h.

[0076] The articles are preferably not based on TC-1, TC-2, TC-3, TC-4 and / or TC-5, but preferably TC-1, TC-2 and TC-5, and polyurethane-coated articles manufactured according to Examples 1, 2 and 5 of WO 2024 / 017706 and optionally Comparative Examples 3 and 4. A detailed description of how articles according to these examples are manufactured, including but not limited to article dimensions, raw materials, processing conditions, measurement methods and properties, is made specifically on pages 41-45 of WO 2024 / 017706 and is hereby specifically incorporated herein by reference. Preferably, Examples 1, 2 and 5 of this disclosed patent application are specifically excluded.

[0077] Thermoplastic compositions preferably do not contain glyceryl monostearate.

[0078] Preferably, the polycarbonate has an end-capping level (EC%) of up to 85%, more preferably 25-85%, more preferably 30-80%, 50-80%, or 65-75%, wherein the end-capping level is calculated using the following formula I:

[0079]

[0080] Where %EC is the end-capping level, ppmOH is the content of terminal hydroxyl groups in parts per million by weight, and Mn is the number-average molecular weight of polycarbonate determined by gel permeation chromatography based on polycarbonate standards. The content of terminal hydroxyl groups can be determined by UV spectroscopy.

[0081] Therefore, the end-capping level is defined as the percentage of non-hydroxyl polycarbonate chain ends. For example, a polycarbonate with a 75 mol% end-capping level means that 25 mol% of the polycarbonate chain ends are hydroxyl groups, typically caused by bisphenol A monomers. The remaining 75 mol% of the end groups do not contain OH end groups and can be phenolic or correspond to end-capping agent molecules.

[0082] In embodiments where the first polycarbonate is molten polycarbonate, the molten polycarbonate preferably has a Fries branching or Fries content of 100-2000 ppm, for example 100-1500 ppm or 400-1200 ppm, or 800-1700 ppm, for example 1000-1500 ppm.

[0083] coating

[0084] The coating in the article of the present invention is obtained by coating a carrier with a liquid paint comprising at least one polyisocyanate and at least one polyol. The resulting coating is a polyurethane coating. The polyisocyanate is preferably a diisocyanate or a triisocyanate or a mixture of diisocyanate and triisocyanate. A single polyisocyanate or a mixture of different polyisocyanates 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 functional groups.

[0085] Those skilled in the art are already familiar with two-component polyurethane coatings, and in principle any available coating system of this kind can be applied in the context of this invention, because the inventors believe that the basic concept of this invention comes from the interaction between the terminal hydroxyl groups of polycarbonate and the isocyanate groups.

[0086] In the context of this invention, the coating is non-foamed, meaning the coating is essentially free of voids, provided that it is acknowledged that the (unintentional) formation of small voids or bubbles may not always be prevented during a typical wet coating process.

[0087] In addition to the isocyanate index, the desired properties of the coating are obtained by selecting appropriate polyisocyanates and polyols. The isocyanate index corresponds to the ratio of free isocyanate groups to reactive isocyanate groups (e.g., hydroxyl groups, amines, and water from the polyol) before the reaction. To avoid confusion, the content of terminal hydroxyl groups in the polycarbonate is not considered in the calculation of the isocyanate index. An isocyanate index of 1 indicates that the equivalent number of isocyanates is the same as the equivalent number of hydroxyl groups, amine groups (if present), and water (if present). Amine groups and water are typically absent. Water has two equivalents per mole, primary amines have two equivalents, and secondary amines have one equivalent. Preferably, the isocyanate index is 0.90-1.2, more preferably 0.95-1.1. A slightly higher isocyanate index is preferred, particularly for polycarbonates with a high number of terminal hydroxyl groups compared to those with a lower number.

[0088] After curing, the coating is preferably at least 50 μm, more preferably at least 100 μm, more preferably at least 250 μm and at most 5000 μm, more preferably at most 4000 μm, and more preferably at most 2500 μm.

[0089] plate

[0090] The articles of the present invention are preferably automotive interior or exterior articles.

[0091] Interior components may be included in or constitute dashboards, instrument panels, control consoles, displays, functional surface trims, door trims, etc.

[0092] External articles may be included in or constitute the front panel, side panel or rear panel of a vehicle.

[0093] Specifically, the article may be included in or constitute the front panel of a vehicle, such as a car, truck, or bus. In such applications, the coating is exposed towards the direction of travel, i.e., outwards. More preferably, the article is included in or constitutes the front panel of an electric vehicle, such as an electric car, truck, or bus. For the avoidance of confusion, the present invention relates to the use of the article as a front panel or as part of a front panel as described above.

[0094] The present invention also relates to a vehicle, such as a fossil fuel-based car, truck, or bus, an electric car, truck, or bus, or a hybrid car, truck, or bus based on both electric and fossil fuels, which includes articles of manufacture according to the invention disclosed herein.

[0095] method

[0096] The present invention also relates to a method for manufacturing the article disclosed herein, the method comprising the following steps:

[0097] i) A certain amount of thermoplastic composition is injected into a mold, thereby forming the carrier by injection molding.

[0098] ii) Cooling injection-molded articles,

[0099] iii) Applying a two-component polyurethane coating containing at least one polyisocyanate and at least one polyol directly to at least a portion of an injection-molded article.

[0100] iv) Allow the coating to cure.

[0101] The thermoplastic composition comprises polycarbonate and the polycarbonate comprises at least 50 wt% of a first polycarbonate based on the weight of the polycarbonate, the first polycarbonate having a terminal hydroxyl content of at least 500 ppm, preferably at least 700 ppm.

[0102] Preferably, the cooled injection-molded article from step ii) is transferred to the second chamber, and at least step iii) is performed in the second chamber.

[0103] More preferably, before applying the coating in step iii), at least a portion of the surface of the injection-molded article to be coated is subjected to corona or flame treatment to further increase the amount of hydroxyl groups on the surface of the injection-molded part.

[0104] Typically, this method is carried out in a process known as flood coating or in-mold coating. In such a process, a carrier is manufactured by injection molding in an injection molding apparatus. After the thermoplastic composition is injected, the carrier thus formed is cooled until it is fully cured. Then, while the carrier is still in the mold, a coating is injected to coat at least one side or a portion of the carrier. This can be done in the same mold, or preferably in a second chamber as described above. The coating is then typically cured under pressure until the carrier can be removed from the mold. After the carrier is removed from the mold, the coating may or may not be fully cured.

[0105] The invention will now be further described based on the following non-limiting embodiments.

[0106] Test methods

[0107]

[0108] polycarbonate materials

[0109] Table 1

[0110]

[0111] All polycarbonates PC1-PC5 are bisphenol A polycarbonate homopolymers.

[0112] Coating adhesion

[0113] Polycarbonate PC1-PC5 was molded into 3 mm thick sheets, and then a two-component polyurethane coating was applied. The polyurethane coating was Puroclear 3351iT, available from Rühl. This coating is a two-component polyurethane coating containing polyester polyol and isocyanate, wherein the weight ratio of polyol to isocyanate is 100:230. The cured coating thickness was 0.6 mm.

[0114] Next, according to standard ISO 4624 Method B (3rd edition, 2016), the coated article thus obtained was subjected to so-called Positest using a Dolly with a diameter of 20 mm and an applied tensile stress rate of 0.7 MPa / s. The adhesive used was LORD 406E / 17 acrylic adhesive. The test was conducted at room temperature of 23 ± 2 °C and relative humidity of 50 ± 5%. As is known to those skilled in the art, Positest is used to test the adhesion of the coating to the substrate.

[0115] After the coating has fully cured (which typically means approximately 24 hours later, but before sample aging), a Positest is performed on the coated article. Another Positest is performed on samples obtained after subjecting the coated and fully cured article to aging cycles according to the BMW PR 303.5b climatic test. This climatic test involves exposing the article to temperature cycles ranging from -30°C to 80°C and under varying relative humidity conditions. The total duration of the cycles is 240 hours. The BMW PR 303.5b climatic test is well known to those skilled in the art.

[0116] The test results are shown in Table 2.

[0117] Table 2

[0118]

[0119] The results shown in Table 2 indicate that polycarbonate articles with a relatively high content of terminal hydroxyl groups exhibit improved adhesion to two-component polyurethane coatings based on isocyanates and polyol monomers. This positive effect was observed both before and after aging. The reason for the difference in Positest results for PC4 and PC5 after aging is not entirely clear to the inventors. A possible explanation may involve differences in the fries content of these polycarbonates.

[0120] In another embodiment, several polycarbonate sheets were provided with a two-component polyurethane coating based on isocyanate and polyol monomers. This coating, Puroclear 3098-4IT, commercially available from Rühl, was applied such that the cured coating thickness was 0.6 mm. After curing, the peel strength of the coating was determined according to ASTM D3167. The results are shown in Table 3 below.

[0121] Table 3

[0122]

[0123] The inventors have discovered that when using interfacial polycarbonate, peel strength cannot be measured in the absence of terminal hydroxyl groups or in the presence of negligible terminal hydroxyl groups.

[0124] The data in this table indicate that lower end-capping levels (EC%) and therefore higher terminal hydroxyl content lead to increased peel strength. The data also show that at terminal hydroxyl content below approximately 700 ppm, the correlation with cooling time of the injection-molded sample before coating is relatively small. The reason for this effect is not entirely clear. It is also understandable that coating adhesion is lower when polycarbonate moldings are cooled for longer periods.

[0125] The inventors also attempted to conduct peel tests using polycarbonate manufactured through an interfacial process, i.e., fully end-capped polycarbonate. The coating peeled off very easily, and the peel strength could not be determined as a result.

[0126] In addition to improved adhesion, the inventors have also discovered that the articles according to the invention exhibit improved impact resistance compared to polycarbonate molding articles with hard coatings or UV-cured coatings (e.g., conventional acrylic or siloxane coatings). This discovery is based on tests conducted on several samples using the so-called "drop tower test procedure," according to ISO 6603-A, where the coated side is the impact side. Specifically, the inventors have found that articles coated with the same paint as those in Examples E1-E3, with an MVR of 21 cm, exhibit improved impact resistance. 3 Impact tests on 3.6 mm thick polycarbonate sheets prepared with molten polycarbonate at 10 min and an end-capping level of 75% and a Fries content of 1050 ppm showed at most ductile fracture. No brittle fracture was observed. In contrast, comparable articles with hard coatings or UV-cured coatings showed only brittle fracture. This aspect is important for using coated articles as front panels of (electric) vehicles.

Claims

1. An article comprising a carrier, wherein the carrier is at least partially provided with a coating, wherein The carrier comprises or is composed of a thermoplastic composition, wherein the thermoplastic composition comprises polycarbonate. The coating is applied directly to the carrier and comprises or consists of a polyurethane obtained by reacting at least one polyisocyanate and at least one polyol. The polycarbonate comprises at least 50 wt% of a first polycarbonate based on the weight of the polycarbonate, the first polycarbonate having a terminal hydroxyl content of at least 500 ppm, preferably at least 700 ppm, the content being determined according to the method described in the specification.

2. The article of claim 1, wherein the polycarbonate comprises at least 75 wt%, preferably at least 90 wt%, more preferably at least 95 wt% of the first polycarbonate.

3. The article of claim 1 or 2, wherein the first polycarbonate is a molten polycarbonate.

4. The article according to any one or more of claims 1-3, wherein the polycarbonate has a thickness of 5-40 cm² as measured according to ISO 1133 (1.2 kg, 300 °C). 3 Melt volume rate per 10 min.

5. The article according to any one or more of claims 1-5, wherein the thermoplastic composition comprises at least 95 wt%, preferably at least 98 wt%, of polycarbonate, based on the weight of the thermoplastic composition.

6. The article according to any one or more of claims 1-6, wherein the polycarbonate composition is substantially composed of bisphenol A polycarbonate homopolymer.

7. The article according to any one or more of claims 1-7, wherein the thermoplastic composition does not contain an antistatic agent.

8. The article according to any one or more of claims 1-8, wherein the polyurethane has an isocyanate index of 0.90-1.2, preferably 0.95-1.1, as defined in the specification.

9. The article according to any one or more of claims 1-8, wherein the polyisocyanate is a diisocyanate or a triisocyanate.

10. The article according to any one or more of claims 1-9, wherein the coating thickness measured after curing is at least 50 μm, preferably at least 100 μm, more preferably at least 250 μm and at most 5000 μm, preferably at most 4000 μm, more preferably at most 2500 μm.

11. The article of manufacture according to any one or more of claims 1-10, wherein the article of manufacture is an internal or external article of a vehicle.

12. A front panel of an electric vehicle comprising or composed of the article of any one or more of claims 1-11.

13. A vehicle, preferably an electric vehicle, comprising a front panel comprising or composed of the article of any one or more of claims 1-11, the front panel being a plate facing the forward direction of the vehicle.

14. A method for manufacturing an article according to any one or more of claims 1-11, comprising the following steps: i) A certain amount of thermoplastic composition is injected into a mold, thereby forming the carrier by injection molding. ii) Cooling injection-molded articles, iii) Applying a two-component polyurethane coating containing at least one polyisocyanate and at least one polyol directly to at least a portion of the injection-molded article. iii) Curing the coating; in, The thermoplastic composition comprises polycarbonate and the polycarbonate comprises at least 50 wt% of a first polycarbonate based on the weight of the polycarbonate, the first polycarbonate having a terminal hydroxyl content of at least 500 ppm, preferably at least 700 ppm.

15. The method of claim 14, further comprising the step of transferring the cooled injection-molded article of step ii) to a second chamber prior to applying the coating in step iii).

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