High clarity and low haze UV stabilized colored styrene and methyl methacrylate copolymers with high gloss retention to UV exposure

Abstract

The invention relates to a colored thermoplastic composition (P) comprising a copolymer (a) of vinylaromatic monomer and methyl methacrylate monomer and at least one dye (b), wherein the at least one dye (b) comprises at least one azo-based dye having at least one –N=N– moiety within the molecular structure. It further relates to a process for the preparation of the thermoplastic composition (P), a process for the preparation of a shaped article, the shaped article, and the use of the components for the preparation of a thermoplastic composition (P). The thermoplastic composition (P) has high clarity, low haze, and high UV stability characterized by a high gloss retention after UV exposure.

Description

[0001] INEOS Styrolution Group GmbH

[0002] High Clarity and Low Haze UV stabilized Colored Styrene and Methyl Methacrylate Copolymers with high gloss retention to UV exposure

[0003] Description

[0004] The invention relates to a colored thermoplastic composition (P) comprising a copolymer (a) of vinylaromatic monomer and methyl methacrylate monomer and at least one dye (b), wherein the at least one dye (b) comprises at least one azo-based dye having at least one -N=N- moiety within the molecular structure. It further relates to a process for the preparation of the thermoplastic composition (P), a process for the preparation of a shaped article, the shaped article, and the use of the components for the preparation of a thermoplastic composition (P). The thermoplastic composition (P) has high clarity, low haze, and high UV stability characterized by a high gloss retention after UV exposure.

[0005] Clear and transparent polymer materials are of considerable importance for many technical applications. It is desirable to make transparent packaging materials such as films (e.g. for food packaging) or plastics moldings (e.g. bottles, boxes, etc.), transparent parts of buildings (e.g. window panes, films, signboards), transparent parts of cars (e.g. panes, screens, exterior lamp cases), transparent parts of electronics (e.g. screen surfaces, cases, lamps), optical fibers or transparent parts of varnish, toys, sports equipment or medical and laboratory equipment.

[0006] In terms of transparency, polymethyl methacrylate polymers (PM MA) bear the desired properties. In particular, PMMA is transparent for visible light and stable towards UV light. However, the technical applicability of PMMA is limited, e.g. by its low dimensional stability due to water absorption, which is associated with the high polarity of the polymer. Furthermore, said water absorption also leads to a change in the refractive index of the polymer, which is particularly undesired in optical applications requiring high precision and accuracy.

[0007] In contrast to PMMA, vinylaromatic polymers, such as, e.g., polystyrene or polymers based on derivatives of styrene or copolymers bear desirable properties in terms of dimensional stability. Furthermore, such vinylaromatic polymers are non-polar, therefore having no issues with high humidity applications, such as refractive index changes.

[0008] SL24 / 75207PC January 13, 2026INEOS Styrolution Group GmbH

[0009] 2

[0010] WO 2015 / 118142 discloses styrene / methyl methacrylate (SMMA) copolymers comprising 20 to 50 wt.-% of methyl methacrylate and 50 to 80 wt.-% of styrene for producing UV-translucent products.

[0011] However, the vinylaromatic moieties of such polymers absorb light in the range of the nearer UV light, in particular in the range of from 250 nm to 370 nm. Therefore, the copolymers comprising typical amounts of vinylaromatic moieties bear impaired transparency properties, especially in this range. Furthermore, due to the absorption of UV light, vinylaromatic polymers can be partially damaged over time, thus that the shaped articles prepared therefrom can become hazy and discolored and lose transparency, even for light in the spectral range outside of the absorbed range. These issues lead to limitations for the use of polymers derived from vinylaromatic monomers, especially in applications where the polymers are exposed to UV light. Therefore, the copolymers comprising typical amounts of vinylaromatic moieties bear impaired transparency properties, especially in this range.

[0012] Due to these limitations, vinylaromatic polymers are typically stabilized with light stabilizers and / or UV absorbers, which help reducing degradation of the polymers due to exposure to UV radiation.

[0013] US 5,624,982 discloses non-yellowing styrenic polymers stabilized with a stabilizer system which comprises a benzotriazole UV absorber (e.g. Tinuvin® 328; BASF), a hydroxyl-benzylisocyanurate primary antioxidant and a hindered amine light stabilizer (HALS). As HALS, an oligomeric condensation product of N,N’(2,2,6,6-tetramethylpiperidinyl)al-kylene diamine and 6-amino-2,4-dichloro-1,3,5-s-triazine which triazine amine group is preferably derived from morpholine (e.g. Cyasorb® 3346), or bis(2, 2,6,6, -tetramethyl-4-piperidinyl) sebacate (e.g. Tinuvin® 770), or bis(1,2,2,6,6,-pentamethyl-4-piperidinyl) ester of (3,5-di-tert-butyl-4-hydroxybenzyl)-butylmalonate (e.g. Tinuvin 144) is used.

[0014] In a long list of suitable styrenic polymers SMMA copolymers are generally mentioned. In all examples of US 5,624,982 a stabilized blend of SAN-copolymers with ASA- and AES- graft copolymers is used which additionally comprises TiC>2 (pigment, inorganic UV-absorber). One of the 50 Examples shows a SAN-copolymer blend comprising a stabilizer system, comprising 0.4 pbw Tinuvin 328, 0.4 pbw Tinuvin 144 and 0.4 pbw Cyasorb 3346.

[0015] SL24 / 75207PCINEOS Styrolution Group GmbH

[0016] 3

[0017] The balance in yellowing performance and weatherability and the transparency of these known blends are still in need of improvement.

[0018] WO 2006 / 057355 discloses resin compositions comprising 100 pbw of a SMMA- copolymer (MMA: 80 to 50 wt.-%), 0.1 to 2 pbw, of a HALS compound and 0.1 to 2 pbw of a benzotriazole compound. As HALS compound one or more derivatives of bis(1 , 2, 2,6,6-pentamethyl-4-piperidiyl)- or bis(2,2,6,6-tetramethyl-4-piperidiyl)dicarboxylic acid di-es-ters may be used. In all examples one HALS compound (Tinuvin 770) and a UV-absorber (Tinuvin 329) are used in a 1:1 weight ratio.

[0019] KR 2010 / 0070143 discloses a styrene resin composition comprising 100 pbw of a methylmethacrylate styrene copolymer (styrene: 50 to 80 wt.-%), 0.05 to 1.0 pbw of a HALS stabilizer, and 0.05 to 1.0 pbw of a benzotriazole UV absorber (all examples: Tinuvin 329, 0.2 pbw). The HALS absorber is of the bis(1, 2,2,6, 6-pentamethyl-4-piperi-diyl)- or bis(2,2,6,6-tetramethyl-4-piperidiyl)dicarboxylic acid diester type (all examples: Tinuvin 770, 0.2 pbw).

[0020] JP 2006 / 154445 discloses a light diffusing plate which layer (B) consists of a resin composition consisting of a SMMA copolymer (MMA: 5 to 50 wt.-%), and further 0.1 to 1 pbw of an UV absorber and 0.1 to 1 pbw of a HALS stabilizer. The UV-absorber can be i.a. of a benzophenone type, cyano acrylate type, salicylic ester type, benzotriazole type, triazine type, and oxal anilide type.

[0021] The afore-mentioned resin compositions comprising SMMA copolymers and stabilizer systems according to the prior art often offer a good indoor UV resistance but their outdoor UV resistance is not satisfying. A stronger UV resistance of said materials is needed in many demanding outdoor applications, in particular applications in the construction or automotive sector.

[0022] WO2023 / 041512 teaches clear and transparent styrene / methyl methacrylate (SMMA) copolymer compositions comprising a combination of at least two hindered amine stabilizers and at least two UV absorbers different from hindered amine stabilizers, which are suited for the preparation of transparent articles with high UV stability even in outdoor applications, and thus can be used, e.g. in the manufacture of transparent articles such as automotive parts.

[0023] SL24 / 75207PCINEOS Styrolution Group GmbH

[0024] 4

[0025] However, the disclosed compositions, while being sufficiently clear and transparent, are colorless. Colored transparent polymer materials are of particular interest for certain applications such as decorative applications, signaling purposes, optical applications and lighting, e.g. in exterior automotive parts such as exterior rear combination lamps of vehicles.

[0026] Particularly desirable are such polymers or compositions which are transparent for visible light of certain wavelengths in a wavelength range of from 380 nm to 800 nm, while not being transparent for certain other wavelengths in this range, to provide color, and remain stable even after being exposed to UV light. For many of the mentioned applications, high gloss and gloss retention after exposure to UV light are also desired, e.g. for aesthetic reasons.

[0027] The introduction of colorants, such as dyes and / or pigments, into thermoplastic polymer compositions is a common practice in the polymer industry, often used for adding color to otherwise colorless products. However, the addition of colorants may have substantial effects on other properties of the thermoplastic polymer compositions.

[0028] WO2015 / 036526 describes black colored thermoplastic molding compositions with high gloss, which mainly comprise styrene acrylonitrile copolymers, carbon black and a mixture of dyes of complementary color regions. These compositions lack the required UV stability, and often are inferior to SMMA-based products in terms of dimensional stability in humid environments. Moreover, these compositions are not transparent and have a black color, making them unsuited for the above-mentioned applications requiring the polymer compositions to be clear and transparent.

[0029] WO 2021 / 250053 discloses thermoplastic molding compositions with improved weathering resistance, comprising a thermoplastic polymer, such as PMMA, carbon black, and a specific dye, which leads to grey or black products with improved weathering resistance, compared with compositions lacking the carbon black or the dye. These compositions lack the required dimensional stability in humid environments due to the use of PMMA. Moreover, these compositions are also not transparent and have a grey or black color, making them unsuited for the above-mentioned applications requiring the polymer compositions to be clear and transparent. Furthermore, the gloss of these compositions may be insufficient.

[0030] SL24 / 75207PCINEOS Styrolution Group GmbH

[0031] 5

[0032] WO 2021 / 198528 teaches black colored thermoplastic molding compositions with high gloss, based on SMMA copolymers, carbon black and a mixture of dyes of complementary color regions. While these compositions may have good dimensional stability in humid environments, these compositions are again not transparent and have a black color, making them unsuited for the above-mentioned applications requiring the polymer compositions to be clear and transparent.

[0033] In view of the above, there is a technical need to provide thermoplastic polymer compositions that are colored and transparent, and have an increased outdoor UV stability and a balance of good optical properties and high outdoor UV stability. Advantageously the compositions also have high dimensional stability in humid environments.

[0034] Surprisingly, it was found that a thermoplastic composition (P) as described below bears such desired properties, whereas compositions employing a different type of dye or other polymers often have insufficient properties.

[0035] Therefore, one aspect of the present invention is a thermoplastic composition (P) comprising (or consisting of) components (a), (b), (c) and optionally (d):

[0036] (a) 95 to 99.96 wt.-%, preferably 97 to 99.9 wt.-%, more preferably 98 to 99.8 wt.-%, more preferably 98.5 to 99.5 wt.-%, based on the total weight of the thermoplastic composition (P), of at least one copolymer (a) comprising (or consisting of) repeating units derived from a vinylaromatic monomer (a1), in particular styrene, and methyl methacrylate (a2);

[0037] (b) 0.01 to 1 wt.-%, preferably 0.05 to 0.8 wt.-%, more preferably 0.1 to 0.6 wt.-%, more preferably 0.2 to 0.4 wt.-%, based on the total weight of the thermoplastic composition (P) of at least one dye (b);

[0038] (c) 0.03 to 3 wt.-%, preferably 0.05 to 2 wt.-%, more preferably 0.1 to 1 wt.-%, more preferably 0.2 to 0.7 wt.-%, based on the total weight of the thermoplastic composition (P), of at least one light-stabilizing additive (c);

[0039] (d) optionally up to 2 wt.-%, preferably up to 1 wt.-%, more preferably up to 0.5 wt.-%, more preferably up to 0.3 wt.-%, based on the total weight of the thermoplastic composition (P), of at least one further additive (d) different from azo-based dyes and light-stabilizing additives, preferably at least one antioxidant;

[0040] wherein the copolymer (a) comprises 30 to 60 wt.-%, preferably 32 to 50 wt.-%, more preferably 35 to 49 wt.-%, more preferably 40 to 48 wt.-% based on the copolymer (a), of repeating units derived from methyl methacrylate (a2); and

[0041] SL24 / 75207PCINEOS Styrolution Group GmbH

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[0043] wherein the at least one dye (b) comprises at least one azo-based dye having at least one -N=N- moiety within the molecular structure.

[0044] Thermoplastic compositions according to the invention and shaped articles thereof have a high outdoor UV stability (UV-resistance), e.g. they can be used for a longer period of time (such as months or years) outdoor with changing temperatures and sun-light. The thermoplastic compositions according to the invention also have good optical properties in terms of transparency / haze and gloss, which, upon UV exposure, deteriorate substantially less than other colored compositions.

[0045] In the context of the present invention, the outdoor UV stability testing is conducted according to SAE J2527 (issued 2004-02) through SAE J 1960 at a radiant exposure of 5000 kJ / m2with Xenon irradiance (wavelength 340 nm) of 0.55 W / m2at 70 °C for light cycle and 38°C for dark cycle.

[0046] In the context of the present invention, the term “good optical properties” means that the haze of the colored thermoplastic composition before outdoor stability testing as described above is 5.0% or less, preferably 2.3% or less, more preferably 1.4% or less (measured according to ASTM D1003-21 using CIE illuminant C, test specimens of 3.125 mm (1 / 8 inch) thickness). The term also means that the gloss of the thermoplastic composition before outdoor stability testing as described above is at least 60 GU (gloss units), preferably at least 70 GU, more preferably at least 75 GU, more preferably at least 80 GU, more preferably at least 85 GU (measured according to ASTM D523-14 (2018) at an observation angle of 20° for a specimen having a thickness of 3.175 mm (1 / 8 inch).

[0047] Furthermore, in the context of the present invention, the term “high outdoor UV stability” means that after outdoor stability testing as described above, at least 60%, preferably at least 70%, more preferably at least 80% of the original gloss value is retained. Preferably, the gloss value after the outdoor stability testing is at least 60 GU, more preferably at least 65 GU, more preferably at least 70 GU, more preferably at least 75 GU.

[0048] Preferably, the term “high outdoor UV stability” also means that the change in the coloration of the composition, characterized by a AE after outdoor stability testing as described above, is less than 4.5, preferably less than 4, measured from the CIE color space values using a D65 light source (observation angle 10°) according to ASTM £1348:2015.

[0049] SL24 / 75207PCINEOS Styrolution Group GmbH

[0050] 7

[0051] Preferably, the term “high outdoor UV stability” also means that the haze after outdoor stability testing as described above is 12% or less, more preferably 10% or less, more preferably 9% or less, more preferably 6.5% or less.

[0052] Preferably, the thermoplastic composition (P) has an L* value in the range from 35 to 47, preferably from 38 to 45, more preferably from 40 to 43, an a* value in the range from 65 to 80, preferably from 68 to 75, more preferably from 70 to 74 and a b* value in the range from 60 to 80, preferably from 62 to 72, more preferably from 64 to 70 measured from the CIE L*a*b* color space values using a D65 light source (observation angle 10°) according to ASTM £1348:2015 before and after outdoor stability testing as described above.

[0053] Another aspect of the invention is a process for the preparation of a thermoplastic composition (P) according to the invention comprising the step of mixing copolymer (a) with the at least one dye (b), the at least one light-stabilizing additive (c) and, if present, the at least one additive (d).

[0054] Another aspect of the invention is a process for the preparation of a shaped article comprising the thermoplastic composition (P), comprising a step of processing the thermoplastic composition (P). A further aspect of the invention is a colored shaped article comprising (or consisting of) a thermoplastic composition (P).

[0055] Moreover, an aspect of the invention is the use of the thermoplastic composition (P) or the colored shaped article of the invention for outdoor applications, such as in the construction and automotive sector.

[0056] Furthermore, an aspect of the invention is the use of components (a), (b), (c) and optionally (d), as defined herein in the amounts as defined herein, for the preparation of a thermoplastic composition (P) or a colored shaped article with the following properties:

[0057] (i) a gloss of at least 70 Gil, measured according to ASTM D523 at an angle of 20° for a specimen having a thickness of 3.175 mm (1 / 8 inch);

[0058] (ii) a haze of less than 5.0%, measured according to ASTM D1003 for a specimen having a thickness of 3.175 mm (1 / 8 inch); and

[0059] (iii) a weathering resistance, which is characterized in that:

[0060] after outdoor stability testing according to SAE J2527 (issued 2004-02) through SAE J 1960 at a radiant exposure of 5000 kJ / m2with xenon irradiance (340 nm) of 0.55 W / m2

[0061] SL24 / 75207PCINEOS Styrolution Group GmbH

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[0063] at 70 °C for the light cycle and 38 °C for the dark cycle, at least 60%, preferably at least 80% of the original gloss value is retained.

[0064] In the following, the invention and the components are described in more detail.

[0065] Copolymer (a)

[0066] The term “copolymer” as used herein for copolymer (a) may be understood in the broadest sense as any polymer obtainable from two or more different types of monomers (i.e. , (a1) at least one kind of vinylaromatic monomer and (a2) at least methyl methacrylate (MMA)) by polymerization. The terms indicating that the copolymer (a) comprises monomers or the polymer consists of monomers will be understood by those skilled in the art as meaning that the monomers in this context are monomeric moieties embedded into the copolymer strand, i.e. repeating units derived from the respective monomers.

[0067] Furthermore, a repeating unit derived from a certain monomer will be understood as a repeating unit obtained from said monomer during polymerization, i.e., “derived” does not mean that the repeating unit is obtained from a derivative of said monomer. For example, a repeating unit obtained by polymerization of alpha-methyl styrene is not considered a repeating unit derived from styrene in the context of the present invention.

[0068] In a preferred embodiment, the vinylaromatic monomer (a1) and methyl methacrylate (a2) in the copolymer (a) are not bound to rubber monomers such as butadiene moieties. Particularly preferably, the vinylaromatic monomer (a1) is styrene.

[0069] Preferably, the melt flow index (MFI) (determined at a temperature of 200°C and at a load of 5 kg according to ASTM procedure D1238 - 20) of the copolymers (a) according to the present invention is less than 50 g / 10 min, more preferably less than 20 g / 10 min, more preferably of less than 10 g / 10 min, often less than 5 g / 10 min.

[0070] In a copolymer (a), the different types of repeating units may be either statistically and homogeneously distributed over the copolymer (random copolymer) or may be located at distinct areas of the polymer strand(s) arranged in blocks (block copolymer). The term “block copolymer” may be understood in the broadest sense as any copolymer having distinct areas of the polymer strand(s) arranged in blocks. Preferably, the copolymer (a) however is a random copolymer.

[0071] SL24 / 75207PCINEOS Styrolution Group GmbH

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[0073] Optionally, the copolymer (a) according to the present invention may also contain one or more methacrylate derivatives other than MMA such as, e.g. ethyl methacrylate (EMA), butyl methacrylate (BMA) and 2-ethyl hexyl methacrylate (2-EHMA), and methacrylic acid. Preferably, such methacrylate derivatives and methacrylic acid constitute for not more than 25 wt.-% of the copolymer mass, more preferably not more than 10 wt.-% of the copolymer mass, often not more than 5 wt.-% of the copolymer mass. More preferably, the copolymer (a) does not contain any further methacrylate derivative other than MMA or methacrylic acid. Particularly preferably, the copolymer (a) does not contain any further methacrylate derivative other than MMA.

[0074] Optionally, the copolymer (a) according to the present invention may also contain one or more cross-linking moiety / moieties such as, e.g., divinylbenzene, in its polymer strand. Preferably, such cross-linking agents constitute for not more than 25 wt.-% of the copolymer mass, more preferably not more than 10 wt.-% of the copolymer mass, often not more than 5 wt.-% of the copolymer mass. Preferably, the copolymer (a) does not contain any cross-linking moieties.

[0075] The copolymer (a) according to the present invention may bear a linear, circular or branched structure. A circular structure is a copolymer strand wherein both ends are connected with another. As used herein, the term “branched structure” may be understood in the broadest sense as any structure deviating from a plain linear or circular structure. Accordingly, in a polymer of branched structure, there is at least one monomer binding to three or more other monomer(s). Preferably, the copolymer (a) of the present invention is an essentially linear or circular copolymer, more preferably an essentially linear copolymer, in particular a linear random copolymer.

[0076] The thermoplastic composition (P) is colored and transparent or at least partly transparent. In particular, when the thermoplastic composition (P) is once heated above the glass transition temperature Tg, subsequently molded and finally cooled below the glass transition temperature Tg, the obtained molding is colored and transparent or at least partly transparent. The Tg-value of the thermoplastic composition (P) can be determined by classical methods.

[0077] SL24 / 75207PCINEOS Styrolution Group GmbH

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[0079] As used throughout the present invention, the expression ’’colored and transparent” may be understood in the broadest sense as ability of letting light pass through, with the exception of light of certain wavelengths of the visible light spectrum. The “certain wavelengths of the visible spectrum” that form the exception from transparency will depend on the absorption of the selected dye component, and define the color of the thermoplastic composition (P) of the invention.

[0080] As used herein, methyl methacrylate (MMA) (a2) is understood in the broadest sense. Herein, the terms “methyl methacrylate”, “methyl methacrylate moiety”, “methyl methacrylate monomer”, “methyl methacrylate monomer moiety”, and similar terms are understood interchangeably.

[0081] As used herein, a vinylaromatic monomer (a1) may be understood in the broadest sense as any as any moiety bearing at least one vinyl residue (-CH=CH2) in its monomeric form and at least one monocyclic or polycyclic aromatic residue known in the art. The person skilled in the art will notice that upon polymerization, the double bond of the vinyl residue is cleaved and is thereby embedded into the polymeric strand. In accordance with international common designation standards, the monomeric moiety as well as the moiety embedded into the polymeric strand is designated as vinylaromatic monomer.

[0082] Herein, the terms “vinylaromatic”, “vinylaromatic moiety”, “vinylaromatic monomer”, “vinylaromatic monomer moiety”, “aromatic vinyl”, “aromatic vinyl moiety”, “aromatic vinyl monomer”, “aromatic vinyl monomer moiety” and similar terms may be understood interchangeably. Preferably, the vinylaromatic monomer bears one vinyl residue (-CH=CH2) and one monocyclic or polycyclic aromatic residue.

[0083] More preferably, the vinylaromatic monomer bears one vinyl residue (-CH=CH2) and one monocyclic aromatic residue, such as styrene.

[0084] In a preferred embodiment, the one or more vinylaromatic monomers (a1) comprise(s) styrene and / or one or more styrene derivative(s). As used herein, a styrene derivative may be any derivative of styrene known in the art such as, e.g.

[0085] alkylated styrene (e.g., alpha-methylstyrene, alpha-ethylstyrene, 2-methylstyrene, 3-me-thylstyrene, 4-methylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene, 2,3-dime-thylstyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, 2,6-dimethylstyrene,2,3-dieth-

[0086] SL24 / 75207PCINEOS Styrolution Group GmbH

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[0088] ylstyrene, 2,4-diethylstyrene, 2,5-diethylstyrene, 2,6-diethylstyrene, 2-methyl-3-ethylsty-rene,2-methyl-4-ethylstyrene, 2-methyl-5-ethylstyrene, 2-methyl-6-ethylstyrene, 3-me-thyl-2-ethylstyrene, 3-methyl-4-ethylstyrene, 3-methyl-5-ethylstyrene, 3-methyl-6-ethylstyrene,4-methyl-5-ethylstyrene, 4-methyl-6-ethylstyrene, 2-ethyl-3-methylstyrene, 2-ethyl-4-methylstyrene, 2-ethyl-5-methylstyrene, 2-ethyl-6-methylstyrene, 3-ethyl-4-methylstyrene, 3-ethyl-5-methylstyrene, 3-methyl-6-ethylstyrene, 4-ethyl-5-methyl-sty-rene, 4-ethyl-6-methylstyrene), halogenated styrene (e.g., e.g., 2-chloro-styrene, 3-chloro-styrene, 4-chloro-styrene, 2-fluoro-styrene, 3-fluoro-styrene, 4-fluoro-styrene, 2,3-di-chloro-styrene, 2,4-di-chloro-styrene, 2,5-di-chloro-styrene, 2,6-di-chloro-sty-rene,2,3-di-fluoro-styrene, 2,4-di-fluoro-styrene, 2,5-di-fluoro-styrene, 2,6-di-fluoro-sty-rene, 2-chloro-3-fluoro-styrene, 2-chloro-4-fluoro-styrene, 2-chloro-5-fluoro-styrene, 2-chloro-6-fluoro-styrene, 3-chloro-2-fluoro-styrene, 3-chloro-4-fluoro-styrene, 3-chloro-5-fluoro-styrene, 3-chloro-6-fluoro-styrene, 4-chloro-5-fluoro-styrene, 4-chloro-6-fluoro-styrene, 2-fluoro-3-chloro-styrene, 2-fluoro-4-chloro-styrene, 2-fluoro-5-chloro-styrene, 2-fluoro-6-chloro-styrene, 3-fluoro-4-chloro-styrene, 3-fluoro-5-chloro-styrene, 3-chloro-6-fluoro-styrene, 4-fluoro-5-chloro-styrene, 4-fluoro-6-chloro-styrene) or hydroxystyrene styrene (e.g., 2-hydroxystyrene, 3-hydroxystyrene, 4-hydroxystyrene, 2, 3-d i hydroxy styrene, 2,4-dihydroxystyrene, 2,5-dihydroxystyrene, 2,6-dihydroxystyrene).

[0089] Particularly preferably, the one or more vinylaromatic monomer according to the present invention is alpha-methylstyrene or styrene, in particular styrene.

[0090] In a preferred embodiment, the one or more vinylaromatic monomers (a1) comprise styrene. In a more preferred embodiment, the one or more vinylaromatic monomers (a1) comprise at least 50 wt.-% styrene, preferably at least 70 wt.-% styrene, more preferably at least 80 wt.-% styrene, more preferably at least 90 wt.-% styrene, based on the total weight of (a1). In a preferred embodiment, the only vinylaromatic monomer (a1) in said copolymer (a) is styrene.

[0091] It is preferable that the copolymer (a) comprises 40 to 70 wt.-% of repeating units derived from vinylaromatic monomers (a1), in particular styrene, and 30 to 60 wt.-% of repeating units derived from methyl methacrylate (a2); more preferable that it comprises 50 to 68 wt.-% of repeating units derived from vinylaromatic monomers (a1), in particular styrene, and 32 to 50 wt.-% of repeating units derived from methyl methacrylate (a2); more preferable that it comprises 51 to 65 wt.-% of repeating units derived from vinylaromatic monomers (a1), in particular styrene, and

[0092] SL24 / 75207PCINEOS Styrolution Group GmbH

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[0094] 35 to 49 wt.-% of repeating units derived from methyl methacrylate (a2); even more preferred is that it comprises 52 to 60 wt.-% of repeating units derived from vinylaromatic monomers (a1), in particular styrene, and 40 to 48 wt.-% of repeating units derived from methyl methacrylate (a2), based on the total weight of copolymer (a).

[0095] Preferably, the copolymer does not comprise any further monomer moieties than MMA and one or more, preferably one, vinylaromatic monomers, in particular styrene. Thus, preferred copolymer (a) consists of repeating units derived from vinylaromatic monomers (a1), in particular styrene, and of repeating units derived from methyl methacrylate (a2) in the afore-mentioned amounts.

[0096] Therefore, preferred are thermoplastic compositions (P) as afore-mentioned, wherein copolymer (a) consists of 32 to 50 wt.-%, preferably 35 to 49 wt.-%, more preferably 40 to 48 wt.-%, based on the total weight of copolymer (a), of repeating units derived from methyl methacrylate (a2), and 50 to 69 wt.-%, preferably 51 to 65 wt.-%, more preferably 52 to 60 wt.-%, based on the total weight of copolymer (a), of repeating units derived from styrene.

[0097] In general, a copolymer (a) according to the present invention may be obtained by any means suitable therefore known in the art. The person skilled in the art knows numerous methods suitable for obtaining such copolymer (a). Well-known conventional polymerization procedures may be employed in the preparation of such copolymer (a) according to the present invention.

[0098] Component (a) is e.g. obtained in a known manner by bulk, solution, suspension, precipitation or emulsion polymerization. Details of these processes are described, for example, in Kunststoffhandbuch, ed. R. Vieweg and G. Daumiller, Vol. V "Polystyrol", Carl-Hanser-Verlag Munich, 1969, p. 118 ff.

[0099] Exemplarily, the copolymer (a) may be prepared by emulsion polymerization, solution polymerization or bulk polymerization. Preferably, heat or radical initiation may be used (including living polymerization methods).

[0100] Methyl methacrylate (MMA) monomers (a) as well as numerous vinylaromatic monomers are commercially available. Others can be easily obtained by standard chemical procedures.

[0101] SL24 / 75207PCINEOS Styrolution Group GmbH

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[0103] As indicated above, a vinyl monomer is characterized by its vinyl group (-CH=CH2) in its monomeric form. Therefore, vinyl monomers may also be obtained from precursor molecules. Exemplarily, precursor molecules bearing an ethyl residue (-CH2-CH3) may be oxidized / dehydrated, halogenated precursor molecules bearing a halogenethyl residue (e.g., -CHCI-CH3, -CH2-CH2CI) may be dehalogenated by eliminating the respective acid (e.g., HCI) or hydroxylated precursor molecules bearing a hydroxyethyl residue (e.g., -CHOH-CH3, -CH2-CH2OH) may be dehydrogenated by eliminating water (e.g., H2O). Then, the respective vinyl monomers are obtainable.

[0104] Copolymerization for the preparation of copolymer (a) may optionally be carried out in the presence of, e.g., one or more solvent(s) and / or one or more initiator(s) (e.g., one or more radical starter(s)).

[0105] The initiation of copolymerization may e.g. be started by thermal decomposition of an initiator (e.g an organic peroxide (e.g., dicumyl peroxide) or an azo compound), photolysis (e.g., with metal iodides, metal alkyls or azo compounds (e.g., azoisobutylnitrile (AIBN))), a peroxide initiator (e.g., benzoyl peroxide), an initiator composition enabling a redox reaction (e.g., reduction of hydrogen peroxide or an alkyl hydrogen peroxide by means of iron ions or other reductants such as, e.g, Cr2+, V2+, Ti3+, Co2+or Cu+), persulfate activation, ionizing radiation (e.g., by means of a-, -, y- or x-rays), electrochemical activation, plasma activation, sonication (e.g., at around 16 kHz) or a ternary Initiator (e.g., benzoyl peroxide-3,6-bis(o-carboxybenzoyl)-N-isopropylcarbazole-di-r|5-indenyl-zicronium dichloride optionally in combination with a metallocene (e.g., indenylzirconium) and / or a peroxide (e.g., benzoyl peroxide).

[0106] In a preferred embodiment, the copolymerization comprises heating of the reaction mixture comprising the monomers above a temperature above 100°C and / or adding one or more polymerization initiator(s) to said reaction mixture.

[0107] The reaction mixture can be maintained or brought to conditions allowing chain elongation of the polymer. For instance, the temperature is set according to the monomer / co-polymer content of the reaction mixture. Exemplarily, as indicated above, the temperature may optionally also be varied during incubation, such as, e.g., constantly or stepwise increased during the polymerization process.

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[0110] Exemplarily, methods for producing copolymer (a) of the present invention may be used as shown in any of GB 464688, GB 531956, GB 863279 and WO 2003 / 051973.

[0111] Dye (b)

[0112] The dye (b) in the thermoplastic composition (P) of the invention comprises, and preferably consists of, at least one azo-based dye. “azo-based” in the context of the present invention means that the dye has at least one -N=N- moiety within the molecular structure, i.e., azomethine dyes, which contain the term “azo” in their designation, are not considered azo-based in the context of the present invention, unless they contain at least one -N=N- moiety within the molecular structure.

[0113] Optionally, the thermoplastic composition (P) may contain the azo-based dye in combination with other dyes that are not azo-based having a similar or different color. For example, the azo-based dye may be combined with one or more dyes that are not azo-based, such as azomethine-based dyes, anthrachinone-based dyes, perimidine-based dyes etc.. Preferably thermoplastic composition (P) does not contain any red perimidine-based dyes. More preferably, the thermoplastic composition (P) does not contain any perimidine-based dyes at all. More preferably, the thermoplastic composition (P) does not contain any dyes other than azo-based dyes.

[0114] In some embodiments, the at least one dye (b) comprises two or more dyes, e.g. three or more dyes, preferably two or more azo-based dyes, e.g. three or more azo-based dyes. In some embodiments, the at least one dye (b) comprises a single dye, and the dye is azo-based.

[0115] The at least one azo-based dye is not particularly limited and may be any known azo-based dye. Preferably the azo-based dye is selected form those azo-based dyes that are not classified as hazardous. Also preferably, the azo-based dye is selected from the solvent dyes class.

[0116] In some embodiments, the at least one azo-based dye does not comprise heteroaromatic moieties. In other embodiments, the at least one azo-based dye comprises at least one heteroaromtic moiety, preferably at least one 1,3,5-triazine-based moiety and / or at least one thiophene-based moiety. In some embodiments, the at least one azo-based dye comprises at least one thiophene-based moiety.

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[0119] In some embodiments, the at least one azo-based dye comprises at least two -N=N-moieties within the molecular structure. In other embodiments, the at least one azo-based dye comoprises a single -N=N- moiety within the molecular structure.

[0120] Exemplary commercial azo-based dyes include Solvent Red 23, Solvent Yellow 77, Solvent Yellow 1 , Solvent Yellow 2, Solvent Red 24, Solvent Yellow 3, 4-Anilinoazobenzene, Azobenzene, Solvent Orange 3, Solvent Yellow 14, Solvent Red 1, Solvent Orange 2, Solvent Red 4, Solvent Orange 7, Magneson II, Solvent Red 19, Solvent Yellow 18, Solvent Red 3, and Solvent Red 195 (Reactive Red 195).

[0121] Preferably, the at least one dye (b) is a red color dye, which would make the thermoplastic composition (P) particularly suited for rear lamp cases of automotives.

[0122] In a preferred embodiment, the azo-based dye is Solvent Red 195 (available from various sources) depicted below.

[0123] >

[0124]

[0125] In another preferred embodiment, the azo-based dye is one available as “KeyPast® Red H” from Milliken™, the structure of which is not known, but which is believed to be a thiophene-azo-based dye such as those disclosed in US 11,633,344.

[0126] It has been surprisingly found that the use of Solvent Red 195 and “KeyPast® Red H” from Milliken™ lead to particularly beneficial results in terms of long-term UV stability, whereas with dyes that are not azo-based, the optical properties deteriorate substantially after UV exposure.

[0127] Light stabilizing additive (c)

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[0130] The at least one light stabilizing additive (c) used in the thermoplastic composition (P) of the invention is not particularly limited and may be any light stabilizing additive (c) or mixture of light stabilizing additives (c) known in the art for stabilizing vinylaromatic monomer containing polymers. For example, the at least one light stabilizing additive (c) may comprise at least one hindered amine light stabilizer (HALS) (c1) and / or at least one UV absorber (c2). Preferably, the at least one light stabilizing additive (c) comprises at least one HALS (c1) and at least one UV absorber (c2).

[0131] Preferably, the at least one light stabilizing additive (c) comprises at least two HALS (c1) and at least one UV absorber (c2) or at least one HALS (c1) and at least two UV absorbers (c2). More preferably, the at least one light stabilizing additive (c) comprises at least two HALS (c1) and at least two UV absorbers (c2).

[0132] If the at least one light stabilizing additive (c) comprises at least two HALS (c1), it preferably comprises at least one high molecular weight hindered amine light stabilizer (HMw-HALS) (c1.1) having a number-average molecular weight (Mn) > (equal to or greater than) 1800 g / mol, preferably > 1900 g / mol more preferably > 2000 g / mol, and at least one low molecular weight hindered amine light stabilizer (LMw-HALS) (c1.2) having a number-average molecular weight of < (equal to or less than) 1000 g / mol, preferably < 900 g / mol, more preferably < 800 g / mol,

[0133] The number average molecular weight of HALS component (c1.1) and (c1.2) can be determined by common analytical methods such as Liquid chromatography-mass spectrometry (LC-MS), Gas chromatography-mass spectrometry (GC-MS) and gel permeation chromatography / size exclusion chromatography (GPC / SEC). Furthermore, NMR-methods can be used. In some cases, the HALS components (c1.1) and (c1.2) have distinct molecular weight, rather than a distribution. In these cases, the number average molecular weight is identical to the distinct molecular weight (formula weight) of the respective component. Often, the HALS components (c1.1) and (c1.2) are commercially available. In these cases, the molecular weights are published by the supplier.

[0134] Where the HALS component has a molecular weight distribution, the number average molecular weight is preferably determined by NMR methods (nuclear magnetic resonance spectroscopy), in particular1H NMR spectroscopy, as described, e.g., in “Polymer Molecular Weight Analysis by1H NMR Spectroscopy” (Josephat U. Izunobi and Clement L. Higginbotham, J. Chem. Educ. 2011, 88, 8, pp. 1098-1104).

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[0137] The hindered amine light stabilizers used in the thermoplastic composition (P) according to the invention are preferably based on 2,2,6,6-tetramethyl-piperidine derivatives, in particular derivatives of 2,2,6, 6-tetramethyl-4-piperidyl-substituted organic compounds. LMw-HALS compounds (c1.2) are preferably composed of one or two units comprising a 2,2,6,6-tetramethyl-piperidine group.

[0138] HMw-HALS compounds (c1.1) preferably are (oligomeric) reaction products based on 2,2,6,6-tetramethyl-piperidine derivatives, often (oligomeric) reaction products based on 2,2,6,6-tetramethyl-piperidine derivatives and 1,3,5-triazine derivatives.

[0139] The number average molecular weight (Mn) of the HMw-HALS (c1.1) often is in the range of 1800 to 15000 g / mol, preferably in the range of 1900 g / mol to 10000 g / mol; more preferably in the range of 2000 to 5000 g / mol.

[0140] Suitable compounds which may be used as HMw-HALS (c1.1) are one or more compounds selected from the group consisting of:

[0141] poly[[6-[(1 , 1 ,3,3-tetramethylbutyl)amino]-1 ,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidinyl)im ino]- 1 ,6-hexanediyl[(2,2,6,6-tetramethyl-4-piperidinyl)imino]]) (MW: 2000-3200 g / mol, e.g. Chimassorb® 944); 1,5,8,12-Tetrakis[4,6-bis(N-butyl-N-1,2,2,6,6-pen-tamethyl-4-piperidylamino)-1,3,5-triazin-2-yl]-1,5,8,12-tetraazadodecane (MW: ~ 2300 g / mol, e.g. Chimassorb 119); N,N’-Bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanedia-mine polymer with 2,4,6-trichloro-1,3,5-triazine reaction products with N-butyl-1-bu-tanamine and N-butyl-2,2,6,6-tetramethyl-4-piperidinamine (MW: 2600 - 3400 g / mol, CAS 192268-64-7, e.g. Chimassorb 2020); 4-Hydroxy-2,2,6,6-tetramethyl-1-piperi-dinethanol-dimethyl succinate copolymer (MW: 3100-4200 g / mol, e.g. Lowilite® 62); Poly[[6-[(1 ,1 ,3,3-tetramethylbutyl)amino]-1 ,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidinyl)imino]-1,6-hexanediyl[(2,2,6,6-tetramethyl-4-piperidinyl)imino]] (MW: 2000 -3300 g / mol, e.g. Lowilite 94); and 1,2,3,4-Butanetetracarboxylic acid, polymer with 2,2-bis(hydroxymethyl)-1,3-propanediol and 3-hydroxy-2,2-dimethylpropanal, 1, 2,2,6, 6-pen-tamethyl-4-piperidinyl ester (MW: ~ 2000 g / mol, CAS 101357-36-2, e.g. Amfine® LA-63).

[0142] Preferred as HMw-HALS (c1.1) are oligomeric reaction products of a 2,2,6,6-tetramethyl-4-piperidyl-substituted organic compound (includes its derivatives) and a 1,3,5-triazine derivative, such as in particular poly[[6-[(1,1,3,3-tetramethylbutyl)amino]-1,3,5-triazine-

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[0145] 2,4-diyl][(2,2,6,6-tetramethyl-4-piperidinyl)imino]-1,6-hexanediyl[(2,2,6,6-tetramethyl-4-piperidinyl)imino]]).

[0146] Suitable compounds which may be used as LMw-HALS (c1.2) are one or more compounds selected from the group consisting of:

[0147] Bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl)sebacate (e.g. Tinuvin® 123);

[0148] Bis(1,2,2,6,6-pentamethyl-4-piperidyl) [[3,5-bis(1 , 1 -dimethylethyl)-4 hydroxyphenyl]me-thyl]butylmalonate (e.g. Tinuvin 144); Bis(2,2,6,6,-tetramethyl-4-piperidyl)sebacate (e.g. Tinuvin 770); Methyl 1,2,2,6,6-pentamethyl-4-piperidyl sebacate, Bis(1, 2,2,6, 6-pentame-thyl-4-piperidinyl)-2-(4-methoxy- benzylidene)malonate; N,N’-bisformyl-N,N’-bis- (2,2,6,6-tetramethyl-4-piperidinyl)- hexamethylendiamine (e.g. llvinul® 4050); Bis(1 ,2,2,6,6-pentamethyl-4-piperidinyl)-2-(4-methoxy-benzylidene)malonate (e.g. Hos-tavin®); Bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate (e.g. Afmine® LA-72); 2, 2,6,6-Tetramethyl-4-piperidinyl stearate (e.g. Cyasorb® LIV3853); 4-Piperidinol-2,2,6,6-tetra-methyl-1-(undecyloxy)-4,4'-carbonate (e.g. Amfine® LA-81); 2,2,6,6-Tetramethyl-4-pi-peridinol (e.g. Lastar® A); 2,2,6,6-Tetramethyl-4-piperidinyl hexadecanoate; and 2, 2,6,6-Tetramethyl-4-piperidinyl octadecanoate; and mixtures thereof, in particular a mixture of Bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate and Methyl 1,2,2,6,6-pentamethyl-4-pi-peridyl sebacate (e.g. Tinuvin 292); a mixture of Bis(1 , 2,2,6, 6-pentamethyl-4-piperidinyl)-2-(4-methoxy- benzylidene)malonate and Methyl 1,2,2,6,6-pentamethyl-4-piperidyl se¬ bacate (e.g. Tinuvin 765); and a mixture of 2,2,6,6-Tetramethyl-4-piperidinyl hexadecanoate and 2,2,6,6-Tetramethyl-4-piperidinyl octadecanoate (e.g. Addworks® ATR 945 mp).

[0149] Preferably the at least one LMw-HALS (c1.2) is a derivative of a bis(2,2,6,6-tetramethyl-4-piperidyl)dicarboxylic acid diester, in particular preferred is bis(2, 2,6,6, -tetramethyl-4-piperidyl)sebacate.

[0150] Preferably the HMw-HALS (c1.1) and the LMw-HALS (c1.2) are used in a weight ratio (c1.1):(c1.2) of from 12:1 to 1:2, more preferably from 6:1 to 1.5:2, more preferably from 4:1 to 1:1, in particular from 3:1 to 1:1.

[0151] Particularly preferably, no further HALS except for (c1.1) and (c1.2) are present in component (b).

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[0154] Preferred UV absorbers (c2) are selected from the group consisting of substituted benzotriazoles, substituted benzophenones, substituted triazines, oxalanilides, substituted resorcinols, salicylates and cyanoacrylates, more preferably from the group consisting of 2-(2-hydroxyphenyl) benzotriazoles, 2-hydroxy-benzophenones and hydroxyphenyl-s-tri azines.

[0155] If the at least one light stabilizing additive (c) comprises at least two UV absorbers (c2), it preferably comprises at least one, preferably one UV absorber (c2.1) having a peak absorption at a wavelength from 310 nm to 380 nm, and at least one, preferably one UV absorber (c2.2) has a peak absorption at a wavelength from 260 nm to less than 310 nm, measured by UV / VIS spectroscopy. Particularly preferably, no further UV absorbers other than (c2.1) and (c2.2) are present in component (c).

[0156] In the present context, peak absorption refers to the absorption maximum with the highest absorbance (i.e. absolute maximum) in the UV / VIS spectrum, when measured in a chloroform solution of the respective UV absorber at a concentration of 10 mg / L.

[0157] The UV absorbers (c2.1) and (c2.2) are preferably selected from the group consisting of substituted benzotriazoles, substituted benzophenones, substituted triazines, oxalanilides, substituted resorcinols, salicylates and cyanoacrylates, more preferably from the group consisting of 2-(2-hydroxyphenyl) benzotriazoles, 2-hydroxy-benzophenones and hydroxyphenyl-s-triazines, which fulfill the peak absorption wavelength requirements.

[0158] For example, the at least one UV absorber (c2.1) having a peak absorption at a wavelength from 310 nm to 380 nm may be selected from the group consisting of 2-(2-hydroxyphenyl) benzotriazoles and 2-hydroxy-benzophenones, and the at least one UV absorber (c2.2) having a peak absorption at a wavelength from 260 nm to less than 310 nm may be selected from the group consisting of hydroxyphenyl-s-triazines and other triazines.

[0159] Preferably, (c2.1) is a 2-(2-hydroxyphenyl) benzotriazole and (c2.2) is hydroxyphenyl triazine. More preferably, (c2.1) is 2-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethyl-butyl)phenol, which is, e.g., commercially available as “Tinuvin® 329” (BASF) and has a peak absorption at 343 nm, and (c2.2) is 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-hexyloxy phenol, which is, e.g., commercially available as “Tinuvin® 1577” (BASF) and has a peak absorption at 274 nm.

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[0162] Furthermore, the weight ratio (c2.1):(c2.2) is preferably from 8:1 to 1:4, more preferably from 6:1 to 1:2, more preferably from 4:1 to 2:3, more preferably from 3:1 to 1.5:2, more preferably from 2:1 to 1:1.

[0163] The weight ratio (c1):(c2) in the composition of the invention is preferably from 5:1 to 1:5, more preferably from 4:1 to 1:2, more preferably from 3:1 to 1:1, more preferably from 3:1 to 4:3.

[0164] Additives (d)

[0165] Optionally the thermoplastic composition (P) according to the invention may comprise up to 2.0 wt.-%, preferably up to 1.0 wt.-%, more preferably up to 0.5 wt.-%, more preferably up to 0.3 wt.-%, based on the total weight of the thermoplastic composition (P), of at least one further additive (d) (= component (d)), which is different from azo-based dyes and light-stabilizing additives. Preferably, the at least one further additive (d) (and thus the entire thermoplastic composition (P)) does not contain carbon black. More preferably, the at least one further additive (d) (and thus the entire thermoplastic composition (P)) does not contain any pigments, fillers or dispersants.

[0166] The amount of component (d), if present, is preferably at least 0.01 wt.-%, more preferably at least 0.02 wt.-%, more preferably at least 0.05 wt.-%, particularly preferably at least 0.1 wt.-%, based on the total weight of the thermoplastic composition (P).

[0167] Suitable additives (d) include all substances customarily employed for processing or finishing the polymers, except of pigments and fillers (see e.g. "Plastics Additives Handbook", Hans Zweifel, 6th edition, Hanser Publ., Munich, 2009).

[0168] Exemplarily, an additive may be a stabilizer for improving thermal stability, a stabilizer for enhancing hydrolysis resistance and chemical resistance, a process stabilizer, a radical scavenger, an antioxidant, an anti-thermal decomposition agent, a glossing agent, a metal deactivator, an antistatic agent, a flow agent, an anti-sticking agent, metal ions, a flame retardant, a dispersing agent, a dye, and / or a (external / internal) lubricant.

[0169] These additives may be admixed at any stage of the manufacturing operation, but preferably at an early stage in order to profit early on from the stabilizing effects (or other specific effects) of the added substance.

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[0172] Preferably component (d) comprises or consists of at least one lubricant and / or at least one antioxidant. More preferably, component (d) is at least one antioxidant.

[0173] Suitable lubricants (glidants / demolding agents) include stearic acids, stearyl alcohol, stearic esters, amide waxes (bisstearylamide, in particular ethylenebisstearamide (EBS)), polyolefin waxes and / or generally higher fatty acids, derivatives thereof and corresponding fatty acid mixtures comprising 12 to 30 carbon atoms.

[0174] Suitable antioxidants are, e.g., one or more compounds selected from monophosphite-based antioxidants, diphosphite-based antioxidants and sterically hindered phenolic antioxidants. If one or more antioxidants are present, they are preferably selected from monophosphite-based antioxidants, such as trisubstituted monophosphite derivatives, diphosphite-based antioxidants, such as substituted pentaerythrirol diphosphite derivatives and sterically hindered phenolic antioxidants, such as 2,6-di-tertbutylphenolic derivatives. More preferably, the antioxidant used as component (d) is one or more compounds selected from tri-phenyl substituted monophosphite derivatives, di-phenyl substituted pentaerythritol diphosphite derivatives and mono-substituted 2,6-di-tert-bu-tylphenolic derivatives. In particularly preferred embodiments, the one or more antioxidants are one or more of tris(2,4-di-tert-butylphenyl)phosphite, bis(2,4-di-tert-bu-tylphenyl)pentaerythritol diphosphite and octadecyl-3-[3,5-di-tert-butyl-4-hydroxy-phenyl]propionate.

[0175] In preferred embodiments, the thermoplastic composition (P) according to the invention consists of the components (a), (b), (c) and optionally (d).

[0176] As indicated above, a further aspect of the invention is a process for the preparation of a thermoplastic composition (P) according to the invention comprising the step of mixing copolymer (a) with the at least one dye (b), the at least one light-stabilizing additive (c) and, if present, the at least one additive (d).

[0177] Components (b), (c) and, if present, (d), can be added to copolymer (a) by separate addition of the individual components or by addition of a mixture of two or more, or all components. Preferably, in the process according to the invention, copolymer (a) is provided in a molten state and components (b), (c) and, if present, (d) are added to a melt of copolymer (a).

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[0180] Components (b), (c) and, if present, (d) may be added to the copolymer (a) in their pure form, or admixed thereto as masterbatches or as a single masterbatch in a polymeric carrier. Preferably, components (b), (c) and, if present, (d), are added to the copolymer (a) as one or more masterbatches in a polymeric carrier.

[0181] When components (b), (c) and, if present, (d) are added as one or more masterbatches in a polymeric carrier, the polymeric carrier preferably comprises, more preferably consists of copolymer (a). Also, the concentration of the respective component(s) in the polymeric carrier is preferably from 20 to 80 wt.-%, more preferably from 25 to 60 wt.-%, more preferably from 30 to 50 wt.-%, based on the total weight of the respective masterbatch.

[0182] Where components (b), (c) and, if present, (d) are added as a masterbatch, their amounts based on the total weight of the thermoplastic composition (P), as specified above, refer to the respective pure component, and not to the masterbatch. Furthermore, where the polymeric carrier comprises or consists of copolymer (a), the amount of copolymer (a) in the masterbatch is counted towards the amount of copolymer (a) based on the total weight of the thermoplastic composition (P), as specified above.

[0183] For example, a thermoplastic composition prepared from 96 wt.-% of copolymer (a), 2 wt.-% of a masterbatch of component (b) (50 wt.-% in copolymer (a)), and 2 wt.-% of a masterbatch of component (c) (50 wt.-% in copolymer (a)) corresponds to a thermoplastic composition (P) consisting of 98 wt.-% of copolymer (a), 1 wt.-% of component (b) and 1 wt.-% of component (c).

[0184] The mixing of the components can be performed by suitable means such as e.g. a mixer, a kneader or an extruder, preferably a twin screw extruder.

[0185] Preferably, if antioxidants are present as component (d), they are added to copolymer (a) separately from components (b), (c) and any further optional additives used as component (d). More preferably components (b), (c) and optional further additives used as component (d) are introduced into the thermoplastic composition (P) during secondary compounding, whereas antioxidants, if present, are introduced into the reactor during the polymerization of copolymer (a).

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[0188] The thermoplastic composition (P) according to the present invention may be used to produce a shaped article therefrom.

[0189] Thus, a further aspect of the invention is a process for the preparation of a shaped article comprising the thermoplastic composition (P), comprising a step of processing the thermoplastic composition (P). For example, the shaped article according to the invention can be formed formed by extrusion, injection molding, casting, blow molding, spraying, spinning, rolling or weaving, in particular extrusion or injection molding of the thermoplastic composition (P) of the invention.

[0190] In this context, the person skilled in the art will know several means for producing one or more of such shaped articles from such molding compositions. Producing a shaped article may e.g. be performed by extrusion, injection molding, casting, blow molding, spraying, spinning, rolling, weaving etc. or a combination of two or more thereof. The person skilled in the art will know which method(s) to apply for producing the respective shaped article.

[0191] The person skilled in the art will also notice that a shaped article in the sense of the present invention may be obtained from at least one thermoplastic composition (P) according to the present invention, which molding composition may either be a melt or present as a raw material for molding processes (e.g. in the form of pellets, powder and / or blocks) or may be dissolved in a suitable solvent.

[0192] Accordingly, a further aspect of the present invention relates to a colored shaped article comprising (or consisting of) a thermoplastic composition (P) according to the present invention. For example, such colored shaped article can be an exterior automotive part, preferably part of an exterior rear combination lamp.

[0193] Thermoplastic compositions (P) according to the invention and shaped articles thereof are generally colored and transparent or at least partly transparent, and have good optical properties and high UV stability. Thermoplastic compositions (P) according to the invention and shaped articles thereof in particular have a high outdoor UV stability. As outlined above, the outdoor UV stability testing is conducted according to SAE J2527 (issued 2004-02) through SAE J 1960 at a radiant exposure of 5000 kJ / m2with Xenon irradiance (wavelength 340 nm) of 0.55 W / m2at 70 °C for light cycle and 38°C for dark cycle.

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[0196] Accordingly, a further aspect of the invention is the use of a thermoplastic composition (P) according to the invention and of colored shaped articles comprising it for outdoor applications, preferably for applications in the construction and automotive sector, in particular for exterior automotive parts, such as e.g. exterior rear combination lamps.

[0197] Yet another aspect of the invention is the use of components (a), (b), (c) and optionally (d), as defined above in the amounts specified above, for the preparation of a thermoplastic composition (P) or a shaped article with following properties:

[0198] (i) a gloss of at least 60 Gil, preferably at least 70 Gil, more preferably at least 75 Gil, more preferably at least 80 Gil, more preferably at least 85 Gil, more preferably at least 90 Gil, measured according to ASTM D523 at an angle of 20° for a specimen having a thickness of 3.175 mm (1 / 8 inch);

[0199] (ii) a haze of 5.0% or less, preferably 2.3% or less, more preferably 1.4% or less, measured according to ASTM D1003 for a specimen having a thickness of 3.175 mm (1 / 8 inch); and

[0200] (iii) a weathering resistance, which is characterized in that:

[0201] after outdoor stability testing according to SAE J2527 (issued 2004-02) through SAE J 1960 at a radiant exposure of 5000 kJ / m2with xenon irradiance (340 nm) of 0.55 W / m2at 70 °C for the light cycle and 38 °C for the dark cycle, at least 60%, preferably at least 70%, more preferably at least 80% of the original gloss value is retained.

[0202] Typically, said use of components (a), (b), (c) and optionally (d) leads to a thermoplastic composition (P) or a shaped article with the above properties, wherein the weathering resistance is further characterized in that after said outdoor stability testing the AE value (i.e. change in color, calculated as

[0203]

[0204] wherein L*o,

[0205]

[0206] and bo’ are the CIE L*, a* and b* values before outdoor stability testing, and L*w, and b are the CIE L*, a* and b* values after outdoor stability testing) is less than 4.5, preferably less than 4, measured from the CIE color space values using a D65 light source (observation angle 10°) according to ASTM £1348:2015.

[0207] Typically, said use of components (a), (b), (c) and optionally (d) leads to a thermoplastic composition (P) or a shaped article with the above properties, wherein the weathering resistance is further characterized in that after said outdoor stability testing the haze is 12% or less, preferably 10% or less, more preferably 9% or less, more preferably 7% or

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[0209] 25

[0210] less, more preferably 6.5% or less, more preferably 3.5% or less, more preferably 3.1% or less, measured according to ASTM D1003 for a specimen having a thickness of 3.175 mm (1 / 8 inch).

[0211] Typically, said use of components (a), (b), (c) and optionally (d) leads to a thermoplastic composition (P) or a shaped article with the above properties, wherein the weathering resistance is further characterized in that after said outdoor stability testing the gloss value after the outdoor stability testing is at least 60 Gil, preferably at least 65 Gil, more preferably at least 70 Gil, more preferably at least 75 Gil, more preferably at least 80 Gil, more preferably at least 90 Gil.

[0212] The invention is further outlined by the following examples and the patent claims.

[0213] Examples

[0214] UV stability testing was conducted according to SAE 2527 through SAE 1960 with xenon irradiance (340 nm) of 0.55 W / m2at 70°C for light cycle and 38°C for dark cycle.

[0215] Haze was measured for 1 / 8” (3.125 mm) thickness specimen according to ASTM D 1003.

[0216] Gloss (in gloss units “GU”)was measured according to ASTM D523 at an angle of 20° for a specimen having a thickness of 3.175 mm (1 / 8 inch)

[0217] CIE color space values measured using a D65 light source (observation angle 10°) according to ASTM E1348.

[0218] As a mixture of copolymer (a) and light stabilizing additives (c), the commercial product NAS® XC UV Plus (INEOS Styrolution) was used, which comprises about 50-60 wt.-% of styrene repeating units, 40-50 wt.-% of methyl methacrylate repeating units, and which is stabilized with a UV package containing HALS components and UV absorbers, such as those described in WO2023 / 041512.

[0219] The copolymer (a) was compounded in a twin screw extruder with different comecially available red dyes at a concentration of 0.3% by weight (3000 ppm) of the respective dye.

[0220] SL24 / 75207PCINEOS Styrolution Group GmbH

[0221] 26

[0222] As dyes, Solvent Red 179 (perimidine-based dye; SR 179), Solvent Red 135 (perimidinebased dye; SR135), Solvent Red 195 (azo-based dye; SR 195) depicted below were used, as well as commercial products “KeyPlast® Resist Red 9995” (advertised as high UV and high heat resist dye, comprising mainly Solvent Red 179; RR 9995) and “KeyPlast® Red H” (advertised as an azo-based dye, structure unknown) from Milliken™.

[0223]

[0224] The obtained styrene-methyl methacrylate (SMMA) copolymer molding compositions were injection molded into the desired shaped article (preparation of various test specimens of 1 / 8 inch (3.175 mm) thickness). As comparative Example C4, a commercial automotive taillight (Ford) based on polymethyl methacrylate (PMMA) was used.

[0225] The obtained test specimens were subjected to CIE L*a*b* color space measurements, gloss measurements and haze measurements as specified above, and then to a simulated outdoor UV stability test as specified above, the CIE L*a*b* color space values, gios and haze were monitored and were documented after completion of the outdoor UV stability test.

[0226] The compositions and their properties are summarized in Table 1 below.

[0227] Table 1 (n.d. = not determined)

[0228]

[0229] SL24 / 75207PCINEOS Styrolution Group GmbH

[0230] 27

[0231]

[0232] From the Examples it can be seen that, while all compositions based on SMMA initially had good optical properties, characterized by a low haze below 5.0% and a high gloss above 70 gloss units (Gil), exposure to weathering conditions led to substantial deterioration of gloss and a substantial increase in Haze in the samples where the dye was not azo-based (Comparative Examples C1, C2 and C3).

[0233] In contrast, the compositions based on SMMA comprising azo-based dyes (Examples 1 and 2) retained most of the gloss (above 80% of the initial value), and the haze increased much less. In addition, the overall color changed to a lesser degree in the compositions comprising azo-based dyes. Thus, the compositions of the invention based on SMMA and containing an azo-based dye showed similar weathering resistance to commercial PMMA-based products (Comparative Example C4).

[0234] However, the overall gloss value of the inventive compositions (Examples 1 and 2) was substantially higher than that of the PMMA-based product both before and after exposure to UV light.

[0235] FIG. 1 shows the course of the gloss retention throughout the outdoor stability testing. While all compositions showed good stability in the first half of the testing, gloss quickly deteriorated in Examples C1, C2 and C3 after 3000 kJ / m2of exposure, whereas Ex. 1, Ex. 2 and the PMMA sample remained stable even after 5000 kJ / m2.

[0236] SL24 / 75207PCINEOS Styrolution Group GmbH

[0237] 28

[0238] The compositions of the invention showed high utility for out-door equipment and articles used with exposure to e.g. sun-light, humidity and temperature changes.

[0239] Exemplary colored articles to be prepared by using the described compositions are:

[0240] films, food packaging, bottles, boxes, window panes, signboards, screens, exterior lamp cases, sports equipment, medical and laboratory equipment, which have the above optical and weathering properties.

[0241] SL24 / 75207PC

Claims

INEOS Styrolution Group GmbH29Patent Claims1. A thermoplastic composition (P) comprising (or consisting of) components (a), (b), (c) and optionally (d):(a) 95 to 99.96 wt.-%, preferably 97 to 99.9 wt.-%, more preferably 98 to 99.8 wt.-%, more preferably 98.5 to 99.5 wt.-%, based on the total weight of the thermoplastic composition (P), of at least one copolymer (a) comprising (or consisting of) repeating units derived from a vinylaromatic monomer (a1), in particular styrene, and methyl methacrylate (a2);(b) 0.01 to 1 wt.-%, preferably 0.05 to 0.6 wt.-%, more preferably 0.1 to 0.5 wt.-%, more preferably 0.2 to 0.4 wt.-%, based on the total weight of the thermoplastic composition (P) of at least one dye (b);(c) 0.03 to 3 wt.-%, preferably 0.05 to 2 wt.-%, more preferably 0.1 to 1 wt.-%, more preferably 0.3 to 0.8 wt.-%, based on the total weight of the thermoplastic composition (P), of at least one light-stabilizing additive (c);(d) optionally up to 2 wt.-%, preferably up to 1 wt.-%, more preferably up to 0.5 wt.-%, more preferably up to 0.3 wt.-%, based on the total weight of the thermoplastic composition (P), of at least one further additive (d) different from azo-based dyes and light-stabilizing additives, preferably at least one antioxidant;wherein the copolymer (a) comprises 30 to 60 wt.-%, preferably 32 to 50 wt.-%, more preferably 35 to 49 wt.-%, more preferably 40 to 48 wt.-% based on the copolymer (a), of repeating units derived from methyl methacrylate (a2); andwherein the at least one dye (b) comprises at least one azo-based dye having at least one -N=N- moiety within the molecular structure.

2. The thermoplastic composition (P) according to claim 1 , wherein the at least one light-stabilizing additive (c) comprises (or consists of) at least one, preferably at least two hindered amine light stabilizers (c1) and at least one, preferably at least two UV absorbers (c2).

3. The thermoplastic composition (P) according to claim 1 or 2, wherein copolymer (a) comprises (or consists of) 31 to 50 wt.-%, preferably 35 to 49 wt.-%, more preferably 40 to 48 wt.-% of repeating units derived from methyl methacrylate (a2), and 50 to 69 wt.-%, preferably 51 to 65 wt.-%, more preferably 52 to 60 wt.-% of repeating units derived from styrene.SL24 / 75207EPINEOS Styrolution Group GmbH304. The thermoplastic composition (P) according to any one of claims 1 to 3, wherein component (d) is present in an amount of at least 0.01 wt.-%, preferably 0.02 wt.-%, more preferably 0.05 wt.-%, more preferably at least 0.1 wt.-%, based on the total weight of the thermoplastic composition (P).

5. The thermoplastic composition (P) according to any one of claims 1 to 4, wherein the composition does not contain carbon black.

6. The thermoplastic composition (P) according to any one of claims 1 to 5, wherein the composition does not contain perimidine-based dyes, preferably any dyes other than azo-based dyes.

7. The thermoplastic composition (P) according to any one of claims 1 to 6, wherein the at least one dye (b) does not comprise heteroaromatic moieties.

8. The thermoplastic composition (P) according to any one of claims 1 to 7, wherein the at least one dye (b) comprises at least two -N=N- moieties within the molecular structure.

9. The thermoplastic composition (P) according to any one of claims 1 to 8, wherein the at least one light-stabilizing additive (c) comprises at least two hindered amine light stabilizers (c1), comprising at least one hindered amine light stabilizer (c1.1) having a number-average molecular weight (Mn) > (equal to or greater than) 1800 g / mol, preferably > 1900 g / mol more preferably > 2000 g / mol, and at least one hindered amine light stabilizer (c1.2) having a number-average molecular weight of < (equal to or less than) 1000 g / mol, preferably < 900 g / mol, more preferably < 800 g / mol, wherein the numberaverage molecular weight is identical to the formula weight of the respective hindered-amine light stabilizer or is determined by1H NMR spectroscopy if the hindered amine light stabilizer has a molecular weight distribution.

10. The thermoplastic composition (P) according to any one of claims 1 to 9, wherein the at least one light stabilizing additive (c) comprises at least two UV absorbers (c2), comprising at least one UV absorber (c1.1) having a peak absorption at a wavelength from 310 nm to 380 nm, and at least one UV absorber (c1.2) having a peak absorption at a wavelength from 260 nm to less than 310 nm, wherein peak absorption refers to the absorption maximum with the highest absorbance in the UV / VIS spectrum, when measured in a chloroform solution of the respective UV absorber at a concentration of 10 mg / L.SL24 / 75207PCINEOS Styrolution Group GmbH3111. A process for the preparation of a thermoplastic composition (P) according to any of claims 1 to 10 comprising the step of mixing copolymer (a) with the at least one dye (b), the at least one light-stabilizing additive (c) and, if present, the at least one additive (d), wherein components (a), (b), (c) and (d) are as defined in any one of claims 1 to 10.

12. A process for the preparation of a shaped article comprising the thermoplastic composition (P) according to any one of claims 1 to 10, comprising a step of processing the thermoplastic composition (P), preferably by extrusion, injection molding, casting, blow molding, spraying, spinning, rolling or weaving, in particular by extrusion or injection molding.

13. A colored shaped article comprising (or consisting of) a thermoplastic composition (P) according to claims 1 to 10, preferably an exterior automotive part, preferably part of an exterior rear combination lamp.

14. The use of the thermoplastic composition (P) according to any one of claims 1 to 10 or the colored shaped article according to claim 13 for outdoor applications, preferably in the construction and automotive sector, more preferably for exterior automotive parts, in particular as exterior rear combination lamps.

15. The use of components (a), (b), (c) and optionally (d), as defined in any one of claims 1 to 10 in the amounts as defined in any one of claims 1 to 10, for the preparation of a thermoplastic composition (P) or a colored shaped article with following properties:(i) a gloss of at least 60 Gil (gloss units), measured according to ASTM D523 at an angle of 20° for a specimen having a thickness of 3.175 mm (1 / 8 inch);(ii) a haze of 5.0% or less, measured according to ASTM D1003 for a specimen having a thickness of 3.175 mm (1 / 8 inch); and(iii) a weathering resistance, which is characterized in that:after outdoor stability testing according to SAE J2527 (issued 2004-02) through SAE J 1960 at a radiant exposure of 5000 kJ / m2with xenon irradiance (340 nm) of 0.55 W / m2at 70 °C for the light cycle and 38 °C for the dark cycle, at least 60%, preferably at least 80% of the original gloss value is retained.SL24 / 75207PC

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