Recyclable plastic part having metallic appearance and automatically identifiable and sortable by NIR spectroscopy

Abstract

Plastic part having an average thickness tpl and containing a mixture of effect pigments comprising a flake-like aluminum pigment obtained by grinding an aluminum or aluminum-based alloy powder in a concentration cAl and a silver-absorbing pearlescent pigment in a concentration cP, where i) for flake-like aluminum pigments having D10 > = 7.0 [mu] m, cAl * tpl is in the range of 0.0 to 0.20 wt.% cm, or ii) for flake-like aluminum pigments having D10 > = 7.0 [mu] m; for a flake-like aluminum pigment having a particle size of 0.5 [mu] m and a particle size of 7.0 [mu] m, cAl * tpl is in the range of 0.0 to 0.036 wt.% cm, with each concentration being wt.% based on the total amount of the plastic part.

Description

[0001] The present invention relates to plastic compositions having a metallic appearance which can be automatically detected by NIR radiation and automatically sorted for recycling purposes.

[0002] The recycling of plastics requires a fast and cost-effective method to sort the various plastics from municipal waste. For about 20 years, NIR (near infrared) spectroscopy has been used in automatic sorting systems. Plastics can be detected by specific vibration absorption bands in the NIR region.

[0003] In order to improve the appearance of plastic products, effect pigments, such as flaky metal pigments, in particular aluminum effect pigments or pearlescent pigments, can be added to plastics. Usually, the effect pigments are mixed with thermoplastic melts by extrusion processes. Aluminum pigments give plastic products a silvery metallic appearance. Since these pigments are opaque to visible wavelengths, they exhibit extremely high hiding power. However, compared with wet coatings, the plane-parallel orientation of flaky pigments in plastics is less pronounced, so the properties known from the application of wet coatings or printing inks, such as flip-flop or high gloss, are not so high in this case.

[0004] It is known that in the case of plastics colored with metallic effect pigments, the ability to detect and identify plastic materials by NIR spectroscopy is reduced. Apparently, the high reflectivity of aluminum to infrared light is also responsible for this phenomenon.

[0005] WO 2020 / 208134 A1 discloses effect pigment mixtures of platelet-shaped aluminum effect pigments and silver pearlescent pigments, and coating formulations containing the mixtures. The document does not mention the use in plastics.

[0006] US 2005 / 0252416 A1 discloses a blend of at least one effect pigment with a small amount of aluminum metal pigment, which has a mirror-like appearance. This effect pigment mixture has a high hiding power and its application is concentrated in coating formulations, especially automotive topcoat compositions. The document does not mention the automatic sorting of plastics by NIR spectroscopy.

[0007] It is therefore an object of the present invention to produce obtainable, inexpensive plastic parts which have a metallic effect appearance, for example with in particular high hiding power, and which can be reliably detected by NIR spectroscopy in automated sorting systems.

[0008] This object is solved by providing a plastic component having an average thickness t pl and a mixture containing effect pigments, the effect pigments comprising a concentration of c Al A flaky aluminum pigment obtained by grinding aluminum or aluminum-based alloy powder and having a concentration of c P Silver absorbing pearlescent pigments,

[0009] in

[0010] i) For the 10 For aluminum flake pigments ≥7.0μm, c Al *t pl is in the range of 0.0 to 0.20 wt. % cm (weight % cm), or

[0011] ii) For the 10 For flake aluminum pigments <7.0 μm, c Al *t pl is in the range of 0.0 to 0.036 wt.% cm, wherein each concentration is wt.% (weight %) based on the total amount of the plastic part.

[0012] The plastic parts according to the invention have a pronounced metallic appearance. This metallic appearance refers in particular to opacity, a relatively high brightness and a specific metallic flip-flop. The flip-flop and brightness of the integrally colored plastic are not as high as those achieved with wet coatings obtained from varnishes or printing inks containing flake-shaped aluminum effect pigments, since the orientation of the flakes in the resin is less pronounced, but still effective. The plastic parts have an outstanding opacity, since the aluminum effect pigments are opaque to visible light. In particular, IR radiation is almost completely reflected by aluminum, which causes problems when detecting in automatic sorting devices. In such sorting devices, the plastic products are first separated so that they do not substantially overlap and are transported at high speed on a belt. By detecting certain types of plastic in reflection by means of an NIR spectrometer, it is clear that the aluminum flakes increase the reflection by not allowing the IR radiation to penetrate deeply into the plastic parts, so that the IR spectrum of the resin cannot be detected with sufficient intensity and accuracy. The aluminum pigments show a covering effect of the plastic parts against the penetration of IR radiation.

[0013] Plastic parts can have many forms, such as films, foils, bottles, trays, containers, flip-tops and closures. When lying on the sorting belt, the plastic parts will be arranged in a statistical or random manner. Due to static reasons, the area in contact with the sorting belt is a relatively large area. The thickness of this area of ​​the plastic part when it is perpendicular to the sorting belt is the thickness t Pl If this thickness is not uniform, an average thickness can be defined. If the plastic part is hollow, the thickness of the area opposite the contact area is the part of the plastic that is detected with the IR beam, so t Pl is the average thickness of the area.

[0014] Average thickness of plastic parts t pl Preferably, it is in the range of 50 μm to 5 mm.

[0015] The opacity of the plastic part depends on the concentration and average thickness of the effect pigments. Pl Therefore, based on the Lambert-Beer law, the opacity can be well determined by the concentration of aluminum effect pigments c Al Or pearlescent pigment concentration c P With the average thickness t pl The product of .

[0016] Metallic effect pigments:

[0017] Aluminum flake pigments can be divided into two categories: the first category is type i), which has medium to low hiding power in overall colored plastics; and type ii), which has high hiding power in overall colored plastics. The hiding power of aluminum flake pigments is mainly determined by their thickness and particle size distribution. For aluminum pigments obtained by grinding, small pigments are usually also thin due to the deep grinding, in this sense, these parameters are relevant.

[0018] For the flake-shaped aluminum pigments of type i), D 10 ≥7.0μm.

[0019] For the flake-shaped aluminum pigments of type ii), D 10 <7.0μm.

[0020] The particle size distribution of pigments is usually expressed by the D value, which refers to the percentile value of the volume average particle size distribution expressed in frequency form.

[0021] Here, the numbers represent the percentage of particles having a size smaller than a particular size contained in the volume average particle size distribution. 50 The value represents the size where 50% of the particles are smaller than or equal to this value; 10 Denotes the size at which 10% of the particles are smaller than or equal to this value. These measurements are performed, for example, by laser granulometry using a particle size analyzer manufactured by Sympatec GmbH (model: Helos / BR). These measurements are performed according to the manufacturer's guidelines. These sizes are determined using the Fraunhofer approximation and the volume average equivalent sphere.

[0022] The span ΔD is defined by the well-known formula (I):

[0023] ΔD=(D 90 -D 10 ) / D 50 (I)

[0024] It is also a measure of the relative width of the particle size distribution.

[0025] Effect pigments of type i) can be roughly considered to be so-called silver dollar aluminum pigments. These effect pigments are obtained essentially by deformation grinding of essentially spherical aluminum powders.

[0026] Aluminium pigments of type ii) are so-called corn flake pigments. They are obtained essentially by pulverising non-spherical aluminium powder. The aluminium powder is subjected to a grinding process under conditions of high energy impact, which pulverises small parts from the flake edges, thereby obtaining a large number of small particles, so that D 10 On the other hand, the aluminum particles obtained by grinding can be sieved in different ways, so the span of the particle size distribution is also important.

[0027] In a further embodiment, the flake-shaped aluminum pigments of type i) have a 10 ≤22.0 μm; in a further preferred embodiment, the flake-shaped aluminum pigments of type i) have a D in the range of 7.0 μm to 12.0 μm 10 In most cases, the D value is in the range of 1.0 μm to 22.0 μm. 10 The valuable flake-shaped aluminum pigments do not present problems with NIR detection of plastics in automated sorting devices.

[0028] In a further embodiment, the flake-form aluminum pigments of type i) have a span ΔD<1.4.

[0029] In a further embodiment, the flake-form aluminum pigments of type ii) have D 10 <6.0 μm. Preferably, the flake-form aluminium pigments of type ii) have a span equal to or greater than 1.20, more preferably greater than 1.40, most preferably greater than 1.60.

[0030] For the flake-shaped aluminum pigments of type i), c Al Concentration and t pl The product of is in the range of 0.0 to 0.20 wt.% cm; for aluminum pigments of type ii), the product is in the range of 0.0 to 0.030 wt.% cm.

[0031] In this context, "flake-form aluminum pigments" may be used interchangeably with the term "aluminum effect pigments."

[0032] When "%" is used to express the concentration, it always means "wt. %" (weight %) based on the total amount of the plastic part, unless otherwise specified.

[0033] Generally, flake-form aluminum pigments of type i) exhibit significantly lower hiding power than flake-form aluminum pigments of type ii), so significantly more aluminum pigment can be used. Type ii) pigments are more sensitive to the hiding effect of IR radiation, so significantly lower concentrations are tolerable.

[0034] In some embodiments, the aluminum effect pigments can be completely replaced by pearlescent pigments, as demonstrated in the experimental section. Although aluminum pigments are generally cheaper than silver-absorbing pearlescent pigments, it is preferred to use a certain minimum amount of aluminum pigment. Therefore, in a more preferred embodiment, for the flake-shaped aluminum pigments of type i), the concentration c of the aluminum effect pigment is Al (wt.%) and t pl The product of c Al *t pl is in the range of 0.02 to 0.20 wt. % cm; for aluminum effect pigments of type ii), c Al *t pl It is in the range of 0.0020 to 0.030 wt. % cm, each concentration being based on the total amount of the plastic part.

[0035] In a further preferred embodiment, for the flake-form aluminum pigments of type i), the concentration c of the flake-form aluminum pigments is Al With t pl The product of is in the range of 0.040 to 0.180 wt.% cm, further preferably in the range of 0.080 to 0.160 wt.% cm, most preferably in the range of 0.100 to 0.150 wt.% cm.

[0036] In a further preferred embodiment, for the flake-form aluminum pigments of type ii), the concentration c of the flake-form aluminum pigments is Al With t pl The product of is in the range of 0.010 to 0.180 wt.% cm, further preferably in the range of 0.080 to 0.026 wt.% cm, most preferably in the range of 0.010 to 0.025 wt.% cm.

[0037] In these respective concentration ranges, optimum values ​​can be achieved with regard to sorting performance, costs and process stability for the precise detection of plastics by NIR.

[0038] The flake-shaped aluminum pigments contained in the plastic component preferably have a d in the range of 7.0 to 95.0 μm. 50 , more preferably in the range of 8.0 to 40.0 μm, most preferably in the range of 8.5 to 30.0 μm.

[0039] The flake-form aluminum pigments of type i) preferably have an average thickness h in the range from 100 to 350 nm. Al , more preferably in the range of 120 to 300 nm. The flake-shaped aluminum pigments of type ii) preferably have an average thickness h in the range of 80 to 170 nm. Al , more preferably in the range of 85 to 150 nm, most preferably in the range of 90 to <120 nm.

[0040] The average thickness can be determined by SEM based on the procedure described in WO 2004 / 087816 A2, page 24, lines 1 to 28 and described in detail in the experimental part.

[0041] In a further embodiment, the flake-shaped aluminum pigment is coated with a metal oxide, which is preferably selected from SiO 2 , Ce-oxide, Mo-oxide, V-oxide, Cr-oxide and mixtures or combinations thereof. Most preferably, the aluminum effect pigment is SiO 2 Coating. Coatings with these metal oxides impart mechanical stability to aluminum pigments and improve their corrosion resistance and weathering stability against humidity and other chemicals.

[0042] Silver absorbing pearlescent pigments:

[0043] The pearlescent pigments in the effect pigment mixture for plastic parts are silver-absorbing pearlescent pigments which have the optical properties of reflecting a metallic appearance. These pearlescent pigments usually have optical properties such that the color obtained by reflection is a substantially neutral silver hue or a slightly tinted hue and covers the range from absorption gray to anthracite. With respect to pearlescent pigments, the hue "anthracite" is also often referred to as "black". In the present invention, the term "silver-absorbing pearlescent pigment" is used to denote pearlescent pigments which have a combination of a neutral silver or slightly tinted reflected color and an absorption hue of gray to anthracite, which provides a metallic-like feature.

[0044] In a preferred embodiment, the silver absorbing pearlescent pigment is selected from the following types:

[0045] a) pearlescent pigments comprising a transparent substrate coated with a high refractive index layer having n>1.8, the high refractive index layer comprising or consisting of iron oxide having Fe(II) ions,

[0046] b) pearlescent pigments comprising a transparent substrate coated with a high refractive index layer with n>1.8, the high refractive index layer comprising titanium suboxide or consisting of titanium suboxide; or pearlescent pigments comprising a transparent substrate coated with a high refractive index layer with n>1.8, the high refractive index layer comprising titanium suboxide or consisting of titanium suboxide optionally coated with a high refractive index layer with n>1.8,

[0047] c) pearlescent pigments comprising a transparent substrate coated with a high refractive index layer having n>1.8, the high refractive index layer comprising or consisting of titanium oxynitride,

[0048] d) pearlescent pigments comprising a transparent substrate coated with a carbon-containing layer, wherein the carbon is encapsulated in the form of particles in another metal oxide layer or is formed as a separate individual layer,

[0049] e) a transparent substrate coated with a first layer and a second layer located on the first layer, wherein the first layer comprises or consists of a mixture of titanium oxide, iron oxide and oxide of at least one of cobalt and chromium, and the second layer comprises titanium oxide,

[0050] Also mixtures or combinations of the pearlescent pigments a) to e), or pearlescent pigments having a mixture or combination of the various coatings mentioned in the pearlescent pigments a) to e).

[0051] The optical properties of silver-absorbing pearlescent pigments for effect pigment mixtures can be evaluated by drawing down a colorless varnish (preferably BASF farblos ZM 26-3025) with a tinting height of 10 wt.% pearlescent pigment on black / white card stock using a 100 μm No. 25 scraper. The total content of non-volatile components in the varnish should be 30 wt.%. The optical properties of the dried scratch coating are measured with a BYK-Mac instrument. Preferably, the color C* of such a scratch coating of silver pearlescent pigment measured on a black background is 15° is ≤15, more preferably ≤14, most preferably ≤10. The hiding power of the silver pearlescent pigment in such a scratch coating can be defined as the ratio L* 75°,黑色 Value / L* 75°,白色 Values, these values ​​are measured on a black to white background. The ratio is preferably above 70%. This high hiding power is mainly achieved by the absorption layer of the pearlescent pigment. The brightness is determined by the L* at a near reflection angle. 15° The value represents; for the pearlescent pigments of the effect pigment mixture in this specific application, this value is preferably greater than 90, more preferably greater than 100, measured on a black background in a scratch coat.

[0052] In a first preferred embodiment a), the silver pearlescent pigment used in the effect pigment mixture is a pearlescent pigment comprising a transparent substrate which is coated with a high refractive index layer having n>1.8, the high refractive index layer comprising iron oxide with Fe(II) ions or consisting of iron oxide with Fe(II) ions. In a further preferred embodiment, the silver pearlescent pigment a) has a coating comprising a metal oxide layer containing Ti and Fe, wherein the iron is predominantly Fe(II) ions, the metal oxide layer preferably being ilmenite (FeTiO 3 ) layer or magnetite (Fe 3 O 4 ) layer or a mixture thereof. In a further preferred embodiment, the pearlescent pigment has a first TiO 2 A coating of a layer of a metal oxide containing Fe(II) ions is followed by a layer of a metal oxide containing Fe(II) ions, which layer preferably consists of ilmenite. EP 1620511 A2 describes pearlescent pigments having a coating containing uniformly distributed ilmenite (FeTiO 3 ). WO 2012 / 130776 A1 describes a pearlescent pigment having a coating comprising a first TiO 2 Other examples of such pearlescent pigments have been described in EP 246523 A2, EP 3119840 A1 (with Al 2 O 3 substrate) or EP 681009 A2 (with other high refractive index coatings). WO 1997 / 043348 A1 describes pearlescent pigments having a 2 Individual ilmenite layers on platelet substrates. The layer thicknesses disclosed in these documents must be reduced to obtain the pearlescent pigments with a silver to grey hue in reflection required for the effect pigment mixtures.

[0053] In a further preferred embodiment, the silver pearlescent pigment comprises the following structure: (a1) a transparent platelet-shaped synthetic substrate, (a2) a titanium oxide layer, followed by (a3) ​​a metal oxide layer containing Ti ions and Fe ions, wherein the Fe ions are mainly Fe(II) ions. 3 ) layer. In a further preferred embodiment, the pearlescent pigment has an iron (III) oxide content of less than 0.5% by weight, based on the total weight of the pigment. All other amounts of Fe ions in the iron oxide are in the Fe (II) oxidation state. Higher amounts of the remaining Fe (III) ions would lead to an undesirable light brown absorption color. The amount of Fe (II) or Fe (III) can be determined using the Mössbauer method. Spectroscopy or determination using XPS analysis can be combined with the sputtering profile. In a further embodiment, the total amount of iron compounds in the silver-absorbing pearlescent pigment of the present invention, calculated as elemental iron, is less than 5.0% by weight, preferably in the range of 1% by weight to 4.3% by weight, particularly preferably in the range of 1.4% by weight to 2.9% by weight, and very particularly preferably in the range of 1.5% by weight to 2.3% by weight, in each case based on the total weight of the pearlescent pigment. By adopting such a low amount of Fe, the silver color can be well developed. Higher amounts of more than 15% by weight can result in pearlescent pigments with too strong absorption colors. In a further preferred embodiment, according to formula (II), pearlescent pigments of type a) have an iron / titanium weight ratio that varies with the coating:

[0054]

[0055] The iron / titanium weight ratio is in the range of 1.0 to 25.0. Here, the "iron content" represents the amount of iron compounds calculated as elemental iron, the "titanium content" represents the amount of titanium compounds calculated as elemental titanium, in each case in the pearlescent pigment and based on the total weight of the pearlescent pigment; wherein the "ratio of coating (wt.%)" represents the weight proportion of the total coating applied to the substrate, based on the total weight of the pearlescent pigment. In other embodiments, this parameter is in the range of 1.2 to 8.0, preferably in the range of 2.0 to 7.5, particularly preferably in the range of 2.5 to 7.0, very particularly preferably in the range of 3.0 to 6.0. This parameter ensures in particular that the pearlescent pigment has the silver color required for the effect pigment mixture.

[0056] In another embodiment b), the silver absorbing pearlescent pigment comprises a transparent substrate coated with a high refractive index layer with n>1.8, the high refractive index layer comprising or consisting of titanium suboxide; or comprises a substrate coated with a high refractive index layer with n>1.8, the high refractive index layer comprising or consisting of titanium suboxide optionally coated with a high refractive index layer with n>1.8. The high refractive index coating with n>1.8 in the second pigment is made of a material different from the titanium suboxide of the substrate, preferably TiO 2 The coated titania layer or titania substrate represents titanium oxide, wherein the formal oxidation number of titanium is lower than 4. They can be represented by the following formula:

[0057] Ti n O 2n-1 (III)

[0058] wherein n is an integer from 1 to 100, preferably n=1 to 10. Typical examples of such compounds are TiO, Ti 2 O 3 、Ti 3O 5 、Ti 4 O 7 Any mixture of these substances may also be included. In a further embodiment, the titanium oxide content may be less than 5% based on the total amount of pigment, and the main component of the titanium oxide is Ti 2 O 3 Commercially available pearlescent pigments with titanium dioxide are, for example, 9605 (Merck).

[0059] In another embodiment c), the silver pearlescent pigment comprises a transparent substrate coated with a high refractive index layer having n>1.8, the high refractive index layer comprising or consisting of titanium oxynitride. Titanium oxynitride can be represented by the following general formula:

[0060] Ti x N y O z (IV)

[0061] Wherein x is 0.2 to 0.6, y is 0.05 to 0.6, z is 0.1 to 0.9, and it contains 25 nitrogen in a solid solution in titanium monoxide. US 4,623,396 A describes such a pearlescent pigment. EP 332071 A1 or EP 735115 A1 describes a pearlescent pigment having a dark blue or light blue color. Wherein the first TiO 2 The layer is reduced with ammonia at a temperature in the range of 750°C to 850°C. If the TiO deposited in the first step 2 The optical thickness of the layer is in the range of 50 to 30 100 nm, resulting in silver effect pigments. EP 842229 B1 describes pearlescent pigments in which flake-shaped TiO is first formed by solidifying a hydrolyzable aqueous solution of a titanium compound on an endless belt. 2 Substrates. These substrates can be other TiO 2 Or other metal oxide coating, and calcined under reducing conditions. Examples of these pearlescent pigments are the grades Paliocrom Blausilber L6000 and L6001, which were previously produced by BASF Colors and Effects GmbH.

[0062] In a further embodiment d), the pearlescent pigment of the effect pigment mixture comprises a transparent substrate coated with a carbon-containing layer, wherein the carbon is encapsulated in the form of particles in another metal oxide layer or is formed as a separate individual layer on at least one high refractive index layer. DE 4227082 A1 discloses pearlescent pigments in which the pearlescent substrate or the TiO-coated pearlescent substrate is coated with an organofunctional silane. 2A pearlescent pigment coated with a silica gel is prepared by calcining or pyrolyzing the pigment in an inert gas atmosphere to obtain a pearlescent pigment containing carbon in a silica matrix and having a dark color. DE 4227082 A1 discloses a similar pearlescent pigment. EP 3230384 A1 discloses a pearlescent pigment having a metallic silver appearance, wherein a high refractive index coating (e.g., TiO 2 ) is coated on top of a very thin layer of pure carbon.

[0063] In a further embodiment e), the pearlescent pigment of the effect pigment mixture comprises transparent substrate platelets, which are coated with a first layer and a second layer located on the first layer, wherein the first layer comprises a mixture of titanium oxide, iron oxide and oxide of at least one of cobalt and chromium or consists of such a mixture, and the second layer comprises titanium oxide. Such pearlescent pigments have a black absorption color and are described in US Pat. No. 6,361,593 B2 and US Pat. No. 6,290,766 B1. Commercial products are available under the brand name Vegetable Black Olive (Sun Colors and Effects).

[0064] In a further embodiment, a mixture or combination of the pearlescent pigments a) to e) themselves or a pearlescent pigment having a mixture or combination of the various coatings mentioned in the pearlescent pigments a) to e) can be used. For example, a pearlescent pigment comprising a coating of a mixture or combination of titanium suboxide and titanium oxynitride can be used.

[0065] In a preferred embodiment, the silver absorbing pearlescent pigment is selected from the group consisting of:

[0066] a) A pearlescent pigment of type a), wherein the pearlescent pigment has a coating comprising a metal oxide layer, the metal oxide layer containing Ti ions and Fe ions, wherein the Fe ions are predominantly Fe(II) ions, the metal oxide layer preferably being ilmenite (FeTiO 3 ) layer, magnetite (Fe 3 O 4 ) or a mixture thereof, or

[0067] b) Pearlescent pigments of type b), wherein the titanium oxide may be of the formula Ti n O 2n-1 (IV) represents, wherein n is an integer from 1 to 10, or

[0068] c) Pearlescent pigments of type c), wherein the titanium oxynitride can be of the formula Ti x N y O z(V) wherein x is 0.2 to 0.6, y is 0.05 to 0.6, z is 0.1 to 0.9, comprising a solid solution of nitrogen in titanium monoxide,

[0069] Also mixtures or combinations of the pearlescent pigments a) to c), or pearlescent pigments having a mixture or combination of the various coatings mentioned in the pearlescent pigments a) to c).

[0070] The transparent substrates for all variants of silver-absorbing pearlescent pigments are usually natural or synthetic mica, glass flakes, SiO 2 Thin sheet, Al 2 O 3 The substrate is preferably glass flakes, natural mica or synthetic mica, because these substrates provide the pearlescent pigment with a pure silver hue and high gloss. In addition, the more expensive substrate SiO is rarely used in the plastics industry. 2 or Al 2 O 3 , because they have the highest cost. In particular, Al 2 O 3 The substrate may have other disadvantages in that pearlescent pigments integrally molded into plastic (e.g. by extrusion) exhibit strong shear forces, which results in the high refractive index layer being peeled off from a portion of the coating. 2 O 3 The flakes may act as an undesirable grinding aid, which may cause an unpleasant tactile feel.

[0071] The high refractive index layer in the silver pearlescent pigment of type a), b) or c) preferably has a refractive index n>2.0, more preferably n>2.3.

[0072] In a preferred embodiment, the silver pearlescent pigment of the present invention may have at least one outer protective layer. Such protective layers further improve the light stability, weathering stability and / or chemical stability of the pearlescent pigment. In particular, these protective layers can effectively reduce any TiO 2 The outer protective layer of the silver pigment according to the invention can comprise or preferably consist of one or two metal oxide layers and / or metal hydroxide layers and / or metal oxide hydrate layers of the elements Si, Al, Zr or Ce. In one variant, a silicon oxide layer is applied as the outermost metal oxide layer, preferably SiO 2After these protective layers, an organofunctional coupling agent can be applied to the outermost protective layer to treat the aluminum effect pigment. In principle, the same organofunctional coupling agents can also be used for silver pearlescent pigments. Such weather-resistant outer protective layers are described, for example, in EP 0 888 410 B1, EP 0 632 10910 A1, EP 1 727 864 B1, EP 1 682 622 B1, EP 2 691 478 B1 or EP 2 904 052 B1.

[0073] Since silver-absorbing pearlescent pigments themselves do not affect the detection and identification of plastic parts in automatic sorting devices and have a distinct metallic appearance and high hiding power compared to conventional pearlescent pigments, these silver-absorbing pearlescent pigments can surprisingly replace at least a portion of the flake-shaped aluminum pigments in plastic parts. This improves the goniochromatic performance, and the use of silver-absorbing pearlescent pigments provides significant process stability for the automated sorting of plastic parts with a metallic appearance.

[0074] Silver absorbing pearlescent pigments are preferably used together with flake-shaped aluminum pigments in an amount such that c P *c Pl In the range of 0.020 to 0.400 cm wt.%, more preferably in the range of 0.030 to 0.300 cm wt.%, most preferably in the range of 0.040 to 0.240 cm wt.%. In these ranges, the concentration of pearlescent pigment is low and can provide cheap plastic parts with high processing flexibility in sorting properties.

[0075] For embodiments without flake-shaped aluminum pigments, the concentration of the pearlescent pigment should be such that c P *c Pl In the range of 0.140 to 2.000 cm wt.%, more preferably in the range of 0.150 to 0.600 cm wt.%, most preferably in the range of 0.160 to 0.300 cm wt.%.

[0076] Plastic parts:

[0077] The plastic material for the plastic part is preferably selected from the group consisting of polypropylene (PP), high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), polyethylene terephthalate (PET), polystyrene (PS), polyurethane (PUR), polyacrylate, polyamide (PA) or nylon, polyvinyl chloride (PVC), polycarbonate (PC) and ABS / MABS.

[0078] Examples of nylon are PA6 (Nylon 6), PA66 (Nylon 6 / 6), PA12 (Nylon 12), PA11 (Nylon 11) (PA), PA69 (Nylon 6 / 9), PA610 (Nylon 6 / 10), PA612 (Nylon 6 / 12), PA46 (Nylon 46), PA6, PA66, PA610, PA11, PA12, PA1010, PA612 and PA46.

[0079] Examples of aromatic polyamides are PA6T, PA9T; examples of semiaromatic polyamides are PA6T / 6, PA6T / 66, PA9T; and an example of polyphthalamide is PA6T / 6I.

[0080] These types of polymers are widely used in the plastics industry and are automatically detectable and sortable using NIR spectroscopy. Most preferred are polypropylene, polyethylene, polystyrene and polyethylene terephthalate.

[0081] The plastic part is most preferably opaque to visible light. In a preferred embodiment, when the average thickness t pl During testing, the optical density OD of the plastic parts is ≥1.5.

[0082] In certain embodiments, metallic pigments may be omitted entirely. Al *t Pl =0.000%). In this case, t Pl With silver absorbing pearlescent pigment concentration c P The product of is preferably 0.40 cm wt.%≤c P *t pl < about 2.0 cm wt.%, more preferably 0.40 cm wt.%≤c P *t pl < about 2.0 cm wt.%.

[0083] Since these embodiments are likely to be the most expensive, it is preferred to use flake-shaped aluminum pigments in plastic parts. Pl With c Al When the product of is within a certain range, the silver absorbing pearlescent pigment has a t Pl *c p The following ranges are preferred:

[0084] II. For aluminum effect pigments of type i):

[0085] α)0.020cm wt.%≤c Al *t pl ≤0.050cm wt.%, 0.100cm wt.%≤c P *t pl≤ about 1.000cm wt.%,

[0086] β)0.05cm wt.% <c Al *t pl ≤0.10cm wt.%, 0.050cm wt.%≤c P *t pl ≤ about 1.0cmwt.%

[0087] γ)0.10cm wt.% <c Al *t pl ≤0.20cm wt.%, 0.02cm wt.% <c P *t pl ≤ about 0.80cmwt.%, or

[0088] III. For aluminum effect pigments of type ii):

[0089] δ)0.002cm wt.%≤c Al *t pl ≤0.020cm wt.%, 0.10cm wt.%≤c P *t pl ≤ about 0.80cmwt.%

[0090] ε)0.020cm wt.% <c Al *t pl ≤0.030cm wt.%, 0.020cm wt.% <c P *t pl ≤about 0.30cmwt.%.

[0091] Especially when using flake-shaped aluminum pigments of type ii), which have a significant influence on the sorting properties, the amount of silver-absorbing pearlescent pigment can be carefully adjusted to the (low) concentration of the flake-shaped metal pigment, so that there is no risk of insufficient sorting properties. Small additions of silver-absorbing pearlescent pigments can improve the angle-dependent color properties. In the case of flake-shaped aluminum pigments of type ii) (corn flake type), the addition of pearlescent pigments can also improve the brightness of the plastic parts.

[0092] In a further embodiment of the plastic component, t Pl With c Al The predetermined range of the product of gives the following range of t to the silver absorbing pearlescent pigment Pl With c p The product of:

[0093] II. For aluminum effect pigments of type i):

[0094] α)0.04cm wt.%≤cAl *t pl ≤0.05cm wt.%, 0.30cm wt.%≤c P *t pl ≤ about 1.0cmwt.%

[0095] β)0.06cm wt.% <c Al *t pl ≤0.10cm wt.%, 0.050cm wt.%≤c P *t pl ≤ about 0.80cmwt.%

[0096] γ)0.10cm wt.% <c Al *t pl ≤0.20cm wt.%, 0.02cm wt.% <c P *t pl ≤ about 0.70 cmwt.%, or

[0097] III. For aluminum effect pigments of type ii):

[0098] δ)0.04cm wt.%≤c Al *t pl ≤0.020cm wt.%, 0.12cm wt.%≤c P *t pl ≤ about 0.80cmwt.%

[0099] ε)0.020cm wt.% <c Al *t pl ≤0.030cm wt.%, 0.080cm wt.% <c P *t pl ≤ about 0.260cmwt.%.

[0100] The plastic part comprising the effect pigment mixture may further contain at least one of additives, UV absorbers, antioxidants, fillers, conventional coloring pigments and additional pearlescent pigments, wherein the additional pearlescent pigment is not a silver absorbing pearlescent pigment.

[0101] As conventional pigments, inorganic pigments or organic pigments can be used. Conventional pigments are understood to mean pigments which have no angular dependence (angle of incidence or angle of observation) in their optical properties, in contrast to effect pigments.

[0102] These conventional pigments are used to impart color to resin moldings, if necessary.

[0103] Conventional pigments may be organic pigments, inorganic pigments or mixtures thereof.

[0104] Thus, in a preferred aspect, the conventional pigment is a transparent pigment, in particular selected from organic pigments, inorganic pigments or mixtures thereof.

[0105] Organic colored absorbing pigments suitable for use in the coating formulations of the present invention include, for example, pigments selected from the group consisting of monoazo, disazo, disazo condensates, anthraquinone, anthraquinone, anthrapyrimidine, benzimidazolone, quinacridone, quinophthalone, diketopyrrolopyrrole, dithioketopyrrolopyrrole, dioxazine, flavonanthrone, isoindolinone, isoindolinone, isoviolanthrone, metal complexes, pyrenone, perylene, pyranthrone, pyrazoloquinazolinone, indigo, thioindigo, triarylcarbonium pigments, and mixtures thereof.

[0106] In a further embodiment, the coating formulation contains additional pearlescent pigments. The additional pearlescent pigments are not any of the pearlescent pigments used in the above-mentioned effect pigment mixtures. The additional pearlescent pigments are characterized in that they are based on a transparent substrate and the layer that contributes to the color is composed of one or two TiO 2 , Fe 2 O 3 or a mixture thereof and optionally one or more low refractive index layers with n<1.8.

[0107] Preferably, these additional pearlescent pigments have a composition consisting of TiO 2 or Fe 2 O 3 A layer composed of, most preferably, TiO 2 A layer composed of TiO 2 "Composition" in this case means that there may be a small amount of SnO 2 , which can be used in a known manner for rutile TiO 2 .

[0108] These additional pearlescent pigments do have essential color properties. They can be used to adjust the color tone or to improve the color flop properties. They generally do not have the opacity and metallic appearance of the pearlescent pigments used for plastic parts containing the effect pigment mixture according to the invention as claimed in claim 1.

[0109] Preferably, the total amount of effect pigments, optionally additional pearlescent pigments and optionally additional conventional pigments of the effect pigment mixture is equal to or less than 10.0 wt.%, based on the total amount of the plastic part, more preferably in the range of 0.200 to 6.000 wt.%, based on the total amount of the plastic part, most preferably in the range of 1.500 to 4.000 wt.%, based on the total amount of the plastic part.

[0110] When the total amount of effect pigments and optionally conventional pigments is above 10 wt.%, the mechanical properties of the plastic part, such as tensile strength, elongation at break, impact strength etc., are significantly adversely affected.

[0111] The plastic parts of the invention are typically used in applications such as electronic and electrical equipment, computers, communications and consumer electronics (3C), household and home appliances, lifestyle products, construction and building industry, sporting goods and luxury goods, consumer products, foils and films, automotive applications, cosmetics and food packaging, toys, and so-called clamshell parts.

[0112] Plastic parts containing effect pigments are typically produced by processes such as extrusion, calendaring, cast film, blown film, blow molding, rotational molding, injection molding, injection blow molding, injection stretch blow molding (ISBM) for containers and packaging, preform stretch blow molding (SBM), pressing, thermoforming, fused deposition modeling (FDM) or fused filament fabrication (FFF), fluidized bed coating, and laser sintering.

[0113] Use and method for sorting plastic parts by NIR spectroscopy

[0114] Another embodiment is directed to a method of separating waste plastic components comprising the steps of:

[0115] a) automatically identifying the properties of a specific plastic component according to the invention in a plastic waste mixture by means of NIR spectroscopy, and

[0116] b) Separating out detected specific pieces of plastic which have been identified from the waste material in step a).

[0117] The waste mixture is conveyed on a belt at a speed of several meters per second. Prior to these steps, the plastic waste is preferably separated in a sorting device so that each plastic part located on the conveyor belt is not covered by another piece. This separation process is usually preceded by other steps, including, for example, particle size separation of the waste pieces, or magnetic separation of magnetic waste pieces, such as tin plates.

[0118] The measured NIR signal is processed by software that compares the spectrum with a database to identify the plastic of a specific scrap piece and then activates a compressed air nozzle to separate the identified plastic part from the conveyor belt. In this way, different types of plastic are separated successively. The detection of specific plastics is usually based on characteristic vibration bands in the spectral range of about 760 to 2500 nm.

[0119] Another embodiment relates to the use of a plastic component in a method for separating waste plastics, comprising the steps of:

[0120] a) automatically identifying the nature of plastics in waste mixtures by IR spectroscopy, and

[0121] b) separating the detected plastic parts of the plastic component according to the invention which have been identified from the waste material in step a). Example:

[0122] Manufacturing samples:

[0123] Several samples were produced by extruding masterbatches of metallic effect pigments (comparative examples) or silver-absorbing pearlescent pigments or mixtures thereof in different concentrations with polypropylene. As aluminum effect pigments, commercially available silver dollar pigments (initially Metalux (abbreviated as MEX) 2156, Eckart GmbH) and commercially available corn flake pigments (STAPA WM Chromal V / 80, Eckart GmbH) were used. The silver dollar pigment paste was first granulated with polyolefin to give granules with 80 wt.% of metallic pigment and 20 wt.% of binder (commercially available as MASTERSAFE MP 16-20B, Eckart GmbH). In all cases where pure aluminum pigments are mentioned, these types are abbreviated hereinafter as "2156" and "Chromal V".

[0124] As silver-absorbing pearlescent pigments, the commercial products Symic C604, Symic B604 and Symic 604 (all from Eckart GmbH) were used. These pearlescent pigments are based on synthetic mica and have TiO 2 and Fe 2 O 3 The coating is calcined under reducing conditions to form TiO 2 and a mixed oxide of iron oxide, the mixture comprising Fe(II) ions.

[0125] The effect pigments were mixed with polypropylene and extruded to form a masterbatch with an effect pigment concentration of 10 wt.%. To prepare the corresponding masterbatches of these effect pigments, the process was as follows:

[0126] a) Pigments in powder form (pearlescent pigments):

[0127] 870 g of polypropylene in granular form (PP; polypropylene R7051-10N BR, from Braskem, Brazil) and 100 g of the corresponding powdered pearlescent pigment were mixed in a tumble mixer and then processed in a twin-screw extruder (from Labtech, Bangkok; diameter 20 mm, 28 L / D) at a process temperature of about 230° C. to form a granular material.

[0128] b) Pigment in paste form (STAPA WM Chromal V / 80):

[0129] 845 g of polypropylene in granular form and 125 g of STAPA WM Chromal V / 80 (a medical white oil paste with a pigment content of 80 wt.% relative to the total weight of the paste) were mixed in a tumble mixer and then processed in a twin-screw extruder (from Labtech, Bangkok; diameter 20 mm, 28 L / D) at a processing temperature of about 230° C. to form a granular material.

[0130] c) Pigment in the form of pellets (MASTERSAFE MP 16-20B):

[0131] 845 g of polypropylene in granular form and 125 g of MASTERSAFE MP 16-20B (pigment content 80 wt. % relative to the total weight of the granules) were mixed in a tumble mixer and then processed in a twin-screw extruder (from Labtech, Bangkok; diameter 20 mm, 28 L / D) at a processing temperature of about 230° C. to form a granular material.

[0132] The masterbatch granules thus obtained were further diluted with polypropylene to the desired final pigment content in proportion by weight relative to the plate. The final concentrations of the effect pigments are listed in Table 2 (pure effect pigments) and Table 3 (effect pigment mixtures). These masterbatch granules were then processed using an injection molding machine (Arburg 221K-75-250) at a processing temperature of 250° C. to form plates having a surface area of ​​100 mm×70 mm and a thickness of 2 mm.

[0133] A1: Evaluation of pure effect pigments:

[0134] Comparative Example Series 1: Various concentrations of Metalux 2156 (processed as Mastersafe mp 16-20b) without pearlescent pigment. This aluminum effect pigment is of the "silver dollar" type. Its particle size parameters measured with Helios / BR are: D 10 =9.6μm, D 50 =18.0μm, and D 90 =28.8μm.

[0135] Comparative Example Series 2: Various concentrations of STAPA WM Chromal V / 80 without pearlescent pigment. This aluminum effect pigment is of the "corn flake" type. Its particle size parameters measured with Helios / BR are: D 10 =4.3μm, D 50 =14.8μm, and D 90 =33.0μm.

[0136] Example series 3: Symic C604 at various concentrations. It is a silver absorbing pearlescent pigment comprising a high refractive index layer containing Fe(II) ions. Median particle size d50,p It is 22μm.

[0137] Example series 4: Symic B604 at various concentrations. It is a silver absorbing pearlescent pigment comprising a high refractive index layer containing Fe(II) ions. Median particle size d 50,p It is 14μm.

[0138] Example series 5: Symic A604 at various concentrations. It is a silver absorbing pearlescent pigment comprising a high refractive index layer containing Fe(II) ions. Median particle size d 50,p It is 9.5μm.

[0139] A2: Evaluation of effect pigment mixtures:

[0140] Example series 6: Mixtures of MASTERSAFE MP 16-20B having an aluminum pigment content of 1.00% with various amounts of Symic B604.

[0141] Example series 7: Mixtures of MASTERSAFE MP 16-20B having an aluminum pigment content of 0.25% with various amounts of Symic B604.

[0142] Example series 8: Mixtures of MASTERSAFE MP 16-20B having an aluminum pigment content of 0.50% with various amounts of Symic B604.

[0143] Example series 9: Mixtures of STAPA WM Chromal V / 80 having an aluminum pigment content of 0.1% and various amounts of Symic A604.

[0144] Example series 10: Mixtures of STAPA WM Chromal V / 80 having an aluminum pigment content of 0.15% and various amounts of Symic A604.

[0145] B: Characterization and test methods of pigments:

[0146] B1: Determination of the average thickness of aluminum effect pigments by SEM:

[0147] The aluminum pigments were initially present in the form of a paste and were each first washed with acetone and then dried.

[0148] The aluminum powder was then poured onto a conductive adhesive label (Spectro tabs, from Plano GmbH, Germany). Through this procedure, a specific amount of flaky aluminum pigment was fixed in an upright position. Using SEM, the particles can be well identified and the thickness at the edge of the pigment determined. For each sample, 100 particles were counted and the average thickness t was determined. Al .

[0149] B2: The specific surface area was measured using the BET method using the three-point method.

[0150] B3: Detection of particle size distribution:

[0151] These tests are carried out, for example, by laser particle size analysis using a particle size analyzer manufactured by Sympatec GmbH (model: Helos / BR). These tests are carried out according to the manufacturer's data. With this device, powdered samples as well as pastes can be tested.

[0152] Table 2 summarizes the different samples with respect to the effect pigments used and the corresponding concentrations.

[0153] A rectangular test piece having a length of 100 mm, a width of 70 mm, and a thickness of 2.0 mm was obtained.

[0154] B4: The optical density of the test pieces was determined using a SW-densitometer (Heiland electronic GmbH TRD 2, Wetzlar, Germany) with a blend diameter of 3 mm. This device can detect the optical density up to a maximum value of 5.5 log.D in transmission mode. After this value, the saturation region (overload) is reached.

[0155] B5: L* values ​​were measured at different observation angles (-15°, 15°, 25°, 45°, 75° and 110°) in the CILAB system using Byk-Mac. The conditions used were D65 (illuminant) and 10° for a standard photometer; the angle of incidence was 45°. L* 15° As a measure of brightness, the color flop is calculated according to the well-known formula (V):

[0156]

[0157] Place black and white paper under the sample plate and measure the L* value. For the ratio L* 10°,黑色 / L* 110°,白色 , it was found that if the ratio was less than 1%, the OD was 1.5.

[0158] B6: In addition, the NIR separation properties of the samples were tested by developing the following test, in which NIR detection was performed by Cyclos-HTP and the sorting performance of the packaged samples was tested.

[0159] The test equipment is a device from Steinert UniSort (Germany) and includes a high-resolution operational NIR camera with full spectrum analysis. The samples are placed on an acceleration belt with a width of 1 m and a speed of 2.5 m / s. This acceleration belt passes through a valve group with a nozzle distance of 13 mm and 7 bar compressed air and includes 19 operational classifiers. The measured data are read with software and visualized as NIR images. Each type of detectable plastic is marked with a predetermined color.

[0160] 1.2 Sample preparation:

[0161] To statistically evaluate the detectable surface, the likelihood of different locations of the sample was evaluated.

[0162] All relevant components of the test sample were also evaluated.

[0163] As the sample size, 10 samples were used for each product.

[0164] 1.3 Details and evaluation of NIR spectroscopy detection:

[0165] Experiment 1: Identification of structure

[0166] 1. Perform sample scans, including detailed imaging of the NIR spectrum and visual evaluation of the detected materials at 0.5 m / s in reflection,

[0167] 2. Record the results (image intensity, image classification, image results),

[0168] 3. Evaluate / check the plausibility of the image (repeat if necessary),

[0169] 4. Professional evaluation of test results.

[0170] The first test was successfully passed when at least 90% of the pixels generated from the sample were attributed to a specific type of plastic.

[0171] Test 2: Actual transfer and detection of discharge behavior:

[0172] 1. Perform validation testing using the action classifier,

[0173] 2. Determine the feeding characteristics by evaluating a minimum of 10 tests at 2.5 m / s for each sample.

[0174] 3. Evaluate NIR results:

[0175] When the unloading characteristics are ≥80%, the sorting test is successfully passed.

[0176] The restricted sorting characteristics are attributed to the drop characteristics being >30% to <80% (test failure), and the sorting test is a definite failure when the drop characteristics are ≤30%.

[0177] result:

[0178] Table 1 summarizes the characterization results of the metallic effect pigments:

[0179]

[0180] Obviously, 2156 belongs to type i) of aluminum pigments and Chromal V belongs to type ii).

[0181] Table 2: Test results of pure effect pigment samples

[0182]

[0183]

[0184] The hiding properties of the two different aluminum effect pigments are significantly different: for Chromal V, the sorting test is met only at very low concentrations (0.15%), while for the 2156 sample, a concentration of 1.0 wt.% can be reached to pass the sorting test. The Chromal sample is significantly smaller and thinner, resulting in a larger number of particles per gram of metallic pigment. This sample also shows a broad particle size distribution (span), resulting in better hiding power compared to the other samples.

[0185] Regardless of their concentration, the three pearlescent effect pigments have no effect on the blanking properties. Symic A604 (Example 5 series) has the greatest hiding power, followed by Symic B604 (Example 4 series) and Symic C604 (Example 3 series). This property can be attributed to the smaller particle size (D 50 values ​​increase within the series).

[0186] Because the synthetic mica is made smaller by grinding, the fraction with smaller particle size also produces thinner particles. 2 The layer thickness is the same for all samples (about 40 nm), so the smallest and thinnest particles (A-series) will show the highest TiO 2 Since this high refractive index layer is primarily responsible for hiding power, the smallest fraction has high hiding power.

[0187] From these tests it is possible to estimate the highest possible concentration of each aluminum pigment. However, operating at these high concentrations can reduce process stability, since plastic objects can behave differently in the case of different shapes and the sorting characteristics also vary in practice from one machine to another. Therefore, a mixture of metallic pigments with pearlescent pigments is more advantageous.

[0188] Table 3: Results for mixtures of metallic effect pigments and pearlescent pigments

[0189]

[0190]

[0191] discuss:

[0192] For the silver dollar aluminum pigment 2156 example series, lower metal pigment concentrations (Example Series 7, 0.25%; Example Series 8, 0.50%) show that the sorting characteristics and identification of polypropylene plastics by NIR spectroscopy are not hindered when the upper limit of the addition of pearlescent pigment is at least 5.0 wt.%. For the series with an upper limit of aluminum pigment (1.0 wt.%; Example Series 6), the test of the material discharge characteristics was not passed when the pearlescent pigment concentration was 5.0 wt.%, while the test was passed at all lower concentrations. In all three series, it can be observed that the angle-dependent color characteristics are slightly increased compared to the samples without pearlescent pigment (Comparative Examples 6a, 7a and 8a). Obviously, the addition of pearlescent pigment improves the angle-dependent color characteristics. The addition of pearlescent pigment generally has a significant effect on the brightness L*. 15° No effect. At higher concentrations of 3.0 wt.% or 5.0 wt.%, an increase can be observed compared to the pure metal pigment; at lower concentrations, the results are irregular. For the example series with Chromal V pigment (Example series 9 and 10), the critical concentration of the metal pigment is significantly lower. The addition of the pearlescent pigment leads to an earlier failure of the sorting properties. For both series, a pearlescent pigment concentration range with good sorting properties can be determined. In all cases, the color flop and brightness are significantly improved by the addition of the pearlescent pigment.

Claims

1. A plastic part having an average thickness t pl and containing a mixture of effect pigments, the mixture of effect pigments comprising a concentration of c Al A flaky aluminum pigment obtained by grinding aluminum or aluminum-based alloy powder and having a concentration of c P Silver absorbing pearlescent pigments, in i) For the 10 For aluminum flake pigments ≥7.0μm, c Al *t pl is in the range of 0.0 to 0.20 wt. % cm, or ii) For the 10 For flake aluminum pigments <7.0 μm, c Al *t pl is in the range of 0.0 to 0.036 wt. % cm, wherein each concentration is wt. % based on the total amount of the plastic part.

2. The plastic part containing a mixture of effect pigments according to claim 1, wherein the silver absorbing pearlescent pigment is selected from the group consisting of: a) pearlescent pigments comprising a transparent substrate coated with a high refractive index layer having n>1.8, the high refractive index layer comprising or consisting of iron oxide having Fe(II) ions, b) pearlescent pigments comprising a transparent substrate coated with a high refractive index layer with n>1.8, the high refractive index layer comprising titanium suboxide or consisting of titanium suboxide; or pearlescent pigments comprising a transparent substrate coated with a high refractive index layer with n>1.8, the high refractive index layer comprising titanium suboxide or consisting of titanium suboxide optionally coated with a high refractive index layer with n>1.8, c) pearlescent pigments comprising a transparent substrate coated with a high refractive index layer having n>1.8, the high refractive index layer comprising or consisting of titanium oxynitride, d) pearlescent pigments comprising a transparent substrate coated with a carbon-containing layer, wherein the carbon is encapsulated in the form of particles in another metal oxide layer or is formed as a separate individual layer, e) a transparent substrate coated with a first layer and a second layer located on the first layer, wherein the first layer comprises or consists of a mixture of titanium oxide, iron oxide and oxide of at least one of cobalt and chromium, and the second layer comprises titanium oxide, Also mixtures or combinations of the pearlescent pigments a) to e), or pearlescent pigments having a mixture or combination of the various coatings mentioned in the pearlescent pigments a) to e).

3. The plastic component according to claim 1 , wherein the flake-form aluminum effect pigments have a d in the range of 7.0 to 95.0 μm, preferably in the range of 8.0 to 40.0 μm. 50 .

4. The plastic component according to claim 1, wherein the flake-form aluminum effect pigments of type i) have an average thickness h in the range from 100 to 350 nm. Al , or / and wherein the flake-form aluminum effect pigments of type ii) have an average thickness h in the range of 80 to 170 nm Al .

5. The plastic component according to claim 1 , wherein for the flake-form aluminum effect pigments of type i), c Al *t pl is in the range of 0.02 to 0.2 wt. % cm, or for flake-shaped aluminum effect pigments, c Al *t pl is in the range of 0.0020 to 0.030 wt. % cm, where c Al It is based on the total amount of the resin molded product.

6. The plastic component according to any one of the preceding claims, wherein t Pl The concentration of silver absorbing pearlescent pigment c P The product is: I. In c Al *t pl =0.000cm wt.%, 0.40cm wt.%≤c P *t pl < about 2.0 cm wt.%, or II. For aluminum effect pigments of type i): α)0.02cm wt.%≤c Al *t pl ≤0.05cm wt.%, 0.10cm wt. % ≤ c P *t pl ≤ about 1.0cm wt.%, β)0.05cm wt.%<c Al *t pl ≤0.10cm wt.%, 0.050cm wt. % ≤ c P *t pl ≤ about 1.0cm wt.%, γ)0.10cm wt.%<c Al *t pl ≤0.20cm wt.%, 0.02cm wt.% <c P *t pl ≤ about 0.80cm wt.%, or III. For aluminum effect pigments of type ii): δ)0.002cm wt.%≤c Al *t pl ≤0.020cm wt.%, 0.10cm wt. % ≤ c P *t pl ≤ about 0.80cm wt.%, ε)0.020cm wt.%<c Al *t pl ≤0.030cm wt.%, 0.020cm wt.% <c P *t pl ≤ about 0.30cm wt.%.

7. The plastic component according to any one of the preceding claims, wherein t Pl The concentration of silver absorbing pearlescent pigment c P The product is: I. In c Al *t pl =0.00cm wt.%, 0.40cm*wt.%≤c P *t pl < about 2.0 cm wt.%, or II. For aluminum effect pigments of type i): α)0.04cm wt.%≤c Al *t pl ≤0.05cm wt.%, 0.30cm wt. % ≤ c P *t pl ≤ about 1.0cm wt.%, β)0.06cm wt.%<c Al *t pl ≤0.10cm wt.%, 0.050cm wt. % ≤ c P *t pl ≤ about 0.80cm wt.%, γ)0.10cm wt.%<c Al *t pl ≤0.20cm wt.%, 0.02cm wt.% <c P *t pl ≤ about 0.70cm wt.%, or III. For aluminum effect pigments of type ii): δ)0.04cm wt.%≤c Al *t pl ≤0.020cm wt.%, 0.12cm wt. % ≤ c P *t pl ≤ about 0.80cm wt.%, ε)0.020cm wt.%<c Al *t pl ≤0.030cm wt.%, 0.080cm wt.% <c P *t pl ≤ about 0.260cm wt.%.

8. The plastic component according to any one of the preceding claims, wherein the optical density OD of the plastic component is ≥ 1.

5.

9. The plastic part according to claim 1 , wherein the aluminum effect pigments are coated with a metal oxide selected from the group consisting of SiO 2 , Ce-oxide, Mo-oxide, V-oxide, Cr-oxide and mixtures or combinations thereof.

10. The plastic part according to any one of the preceding claims, wherein the silver pearlescent pigment is selected from the group consisting of: a) a pearlescent pigment of type a), wherein the pearlescent pigment has a coating comprising a metal oxide layer, The metal oxide layer contains Ti ions and Fe ions, wherein the Fe ions are mainly Fe(II) ions. The metal oxide layer is preferably ilmenite (FeTiO 3 ) layer, magnetite (Fe 3 O 4 ) or a mixture thereof, b) Pearlescent pigments of type b), wherein the titanium oxide can be represented by the following formula: Of n SHE 2n-1 (III) Where n is an integer from 1 to 10, c) Pearlescent pigments of type c), wherein the titanium oxynitride can be represented by the following formula: Of x N y SHE z (IV) wherein x is from 0.2 to 0.6, y is from 0.05 to 0.6, and z is from 0.1 to 0.9, comprising a solid solution of nitrogen in titanium monoxide, Also mixtures or combinations of the pearlescent pigments a) to c), or pearlescent pigments having a mixture or combination of the various coatings mentioned in the pearlescent pigments a) to c).

11. The plastic part according to any one of the preceding claims, wherein the silver pearlescent pigment is a pearlescent pigment of type a) and comprises the following structure: (a) Transparent platelet-shaped synthetic substrate, (b) titanium oxide layer, followed by (c) metal oxide layer containing Ti ions and Fe ions, wherein the Fe ions are mainly Fe(II) ions.

12. The plastic part according to any one of the preceding claims, wherein the plastic material is selected from the group consisting of polypropylene (PP) high density polyethylene (HDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), polyethylene terephthalate (PET), polystyrene (PS), polyurethane (PUR), polyacrylate, polyamide (PA) or nylon, polyvinyl chloride (PVC), polycarbonate (PC) and ABS / MABS.

13. Plastic part comprising the effect pigment mixture according to any one of claims 1 to 12 and additionally comprising at least one of additives, fillers, conventional coloring pigments and additional pearlescent pigments, wherein the additional pearlescent pigment is not a silver-absorbing pearlescent pigment.

14. The plastic part according to any of the preceding claims, wherein the total amount of effect pigments, optionally additional pearlescent pigments and optionally additional conventional pigments in the effect pigment mixture is equal to or less than 10.0 wt.%, based on the total amount of the plastic part, preferably in the range of 0.20 to 6.00 wt.%, based on the total amount of the plastic part.

15. The plastic component according to any one of the preceding claims, wherein the average thickness t pl It is in the range of 50μm to 5mm.

16. The plastic component according to claim 1, wherein the flake-form aluminum pigments of type i) have a D in the range of 7.0 μm to 12.0 μm. 10 value.

17. Use of the plastic component according to claims 1 to 16 in a method for separating waste plastics, The following steps are involved: a) automatically identifying the nature of plastics in waste mixtures by IR spectroscopy, and b) separating the detected plastic parts according to any one of claims 1 to 15 which have been identified from the waste material in step a).

18. A method for separating waste plastic components, The following steps are involved: a) automatically identifying the properties of a specific plastic component according to any one of claims 1 to 16 in a waste mixture by NIR spectroscopy, and b) Separating out detected specific plastic parts which have been identified from the waste material in step a).

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