Polypropylene composition and light source cover made thereof

Abstract

This disclosure provides a cover for a light source comprising a polyolefin composition comprising: (A) 50% to 80% by weight of a propylene polymer comprising, by weight of (A), at most 40% by weight of units derived from ethylene and / or at least one α-olefin of the formula CH2=CHR1, wherein R1 is a straight-chain or branched C2 to C8 alkyl group; and (B) 15% to 35% by weight of an elastomer component selected from the group consisting of: (B1) A copolymer of ethylene with at least one α-olefin of the formula CH2=CHR2, wherein R2 is a linear or branched C1 to C8 alkyl group, (B2) a saturated or unsaturated styrene or α-methylstyrene block copolymer, and (B3) combinations thereof; (C) 5% to 30% by weight of glass fiber, and (D) 0% to 5.0% by weight of compatibilizer, wherein the amounts of (A), (B), (C) and (D) are based on the total weight of (A)+(B)+(C)+(D), which is 100%.

Description

Technical Field

[0001] This disclosure relates to a propylene polymer composition and a light source cover that can be obtained from the propylene polymer composition. Background Technology

[0002] Glass-filled polyolefins are widely used in the automotive industry for injection molding of interior and exterior components. Glass-filled polyolefins possess several advantageous properties, such as high strength and stiffness.

[0003] However, soft-touch materials are preferred for automotive interiors to increase the tactile appeal of the surface and create a living room feel inside the car.

[0004] Filled polyolefin compositions for injection molding that have a good balance between strength and toughness are known in the art.

[0005] U.S. Patent 5,916,953 discloses a tough, robust, and rigid glass-filled polyolefin composition comprising a highly isotactic propylene polymer, glass fiber, a plastomer copolymer of ethylene and C4 to C6 α-olefins, and a compatibilizer.

[0006] Patent application US2016 / 0160017 discloses how to blend low molecular weight random polypropylene and ultra-high molecular weight polypropylene into a polyolefin composition comprising isotactic polypropylene base resin, inorganic filler and rubber to improve the mechanical properties, flowability and impact strength of the composition.

[0007] Patent application WO2007 / 025663 discloses a molding composition having a pleasantly soft touch, high rigidity and good scratch resistance, comprising a combination of a soft material, a glass material as filler and a thermoplastic propylene polymer.

[0008] Beyond their mechanical properties, the optical properties of plastics are also relevant in the automotive sector, as original equipment manufacturers (OEMs) tend to create new cars with futuristic interior and exterior designs, such as light strips or dots covered with plastic materials. Backlight components primarily use polymethyl methacrylate (PMMA) or polycarbonate (PC).

[0009] In this context, a plastic material is needed that has a good balance between mechanical properties (especially impact and stiffness) and suitable optical properties for manufacturing articles that can be backlit to allow light to pass through them. Summary of the Invention

[0010] This disclosure provides a cover for a light source comprising a polyolefin composition, the polyolefin composition comprising:

[0011] (A) 50% to 80% by weight of a propylene polymer, the propylene polymer comprising up to and including 40% by weight of ethylene and / or at least one of the formula CH2=CHR. 1 The unit of α-olefin, wherein R 1 It is a straight-chain or branched C2 to C8 alkyl group;

[0012] (B) 15% to 35% by weight of an elastomer component, wherein the elastomer component is selected from the group consisting of:

[0013] (B1) Ethylene and at least one of the following formulas: CH2=CHR 2 A copolymer of α-olefins, wherein R 2 It is a straight-chain or branched C1 to C8 alkyl group;

[0014] (B2) Saturated or unsaturated styrene or α-methylstyrene block copolymers, and

[0015] (B3) Their combinations;

[0016] (C) 5% to 30% by weight of glass fiber, and

[0017] (D) 0% to 5.0% by weight of compatibilizer,

[0018] The quantities of (A), (B), (C) and (D) are calculated as the total weight of (A) + (B) + (C) + (D), and the total weight is 100%.

[0019] This disclosure further provides the use of the polyolefin composition as a cover for a light source and a process for manufacturing a cover for a light source, the process including the use of the polyolefin composition as described above.

[0020] The polyolefin composition disclosed herein is translucent and has low absorbance in the visible region of the spectrum. These properties make the composition suitable for manufacturing articles that can be backlit, allowing light to pass through without obscuring the light source behind them, such as covers for light sources.

[0021] Furthermore, the absorbance does not change significantly across the entire visible spectrum, thus allowing light of different colors to pass through the article with essentially the same intensity.

[0022] The polyolefin compositions disclosed herein are also endowed with a good balance of mechanical properties (particularly flexural modulus and impact) and low shrinkage. Therefore, they are suitable for manufacturing light source covers with both aesthetic and structural functions.

[0023] Although several embodiments have been disclosed, other embodiments will become apparent to those skilled in the art from the following detailed description. It will be apparent, as some embodiments disclosed herein, can be modified in various obvious ways without departing from the spirit and scope of the claims set forth herein. Therefore, the following detailed description should be considered illustrative in nature rather than restrictive. Attached Figure Description

[0024] Figure 1 A graph is provided showing the absorbance values ​​measured on a 100 μm thick film having compositions of comparative examples CE11 and CE12 and examples E13 to E15 according to this disclosure. Detailed Implementation

[0025] In the context of this disclosure;

[0026] - Percentages are expressed by weight unless otherwise stated;

[0027] - When the term "comprising" refers to a polymer or polymer composition, mixture or blend, it should be interpreted as meaning "comprising or substantially consisting of";

[0028] The term "substantially composed of" means that, in addition to those mandatory components, other components may be present in the polymer or polymer composition, mixture, or blend, provided that the essential characteristics of the polymer or composition are not substantially affected by their presence. Examples of components that, when present in conventional amounts, do not substantially affect the properties of the polymer or polyolefin composition, mixture, or blend are catalyst residues, antistatic agents, melt stabilizers, light stabilizers, antioxidants, and acid stabilizers.

[0029] The polyolefin composition includes:

[0030] 50% to 80% by weight, preferably 55% to 75% by weight, more preferably 60% to 70% by weight of propylene polymer (A);

[0031] 15% to 35% by weight, preferably 15% to 30% by weight, more preferably 20% to 23% by weight of the elastomer component (B);

[0032] 5% to 30% by weight, preferably 5% to 25% by weight, more preferably 7% to 20% by weight of glass fiber (C);

[0033] 0.15% to 5.0% by weight, more preferably 0.20% to 3.0% by weight, of compatibilizer.

[0034] The quantities of (A), (B), (C) and (D) are calculated as the total weight of (A) + (B) + (C) + (D), and the total weight is 100%.

[0035] In the polyolefin compositions disclosed herein, components (A), (B), (C) and optional (D) are preferably selected from the following components, which may be included in the composition in any combination.

[0036] The propylene polymer (A) may be a random copolymer of propylene, a polyolefin composition including a random copolymer of propylene, or a multiphase propylene polymer including a crystalline or semi-crystalline matrix phase and a rubber phase dispersed therein.

[0037] In all of the following embodiments, R 1 Preferably, the alkyl group is selected from the group consisting of: butene-1, hexene-1, 4-methyl-1-pentene, octene-1 and combinations thereof, with butene-1 being the most preferred.

[0038] The propylene polymer (A) is preferably selected from the group consisting of:

[0039] (A1) Propylene and ethylene and / or at least one of the formula CH2=CHR 1 A copolymer of α-olefins, wherein R 1 The copolymer is a straight-chain or branched C2 to C8 alkyl group, comprising up to and including 8.5% by weight (A1), preferably from 0.1% to 8.5% by weight, of units derived from ethylene and / or α-olefins.

[0040] (A2) A polypropylene composition comprising:

[0041] (A2.1) 25% to 65% by weight of propylene homopolymer or propylene with ethylene and / or at least one of the formula CH2=CHR 1 A copolymer of α-olefins, wherein R 1 The copolymer is a straight-chain or branched C2 to C8 alkyl group, comprising up to and including 2% by weight, preferably from 0.1% to 2% by weight, units derived from ethylene and / or α-olefins, based on (A2.1); and

[0042] (A2.2) 35% to 75% by weight of propylene with ethylene and / or at least one of the formula CH2=CHR 1 A copolymer of α-olefins, wherein R 1 The copolymer is a straight-chain or branched C2 to C8 alkyl group, comprising up to and including 15% by weight, preferably from 0.1% to 15% by weight, units derived from ethylene and / or α-olefins, based on (A2.2).

[0043] The quantities of (A2.1) and (A2.2) are calculated as the total weight of (A2.1) + (A2.2), which is 100%.

[0044] (A3) A polypropylene composition comprising:

[0045] (A3.1) 55% to 80% of a propylene polymer, the propylene polymer being selected from the group consisting of: propylene homopolymers, propylene and ethylene and / or at least one of the formula CH2=CHR 1 copolymers of α-olefins and mixtures thereof, wherein R 1 The copolymer is a straight-chain or branched C2 to C8 alkyl group, comprising up to and including 10% by weight, preferably from 0.1% to 10% by weight, of units derived from ethylene and / or α-olefins based on (A3.1).

[0046] (A3.2) 20% to 45% by weight of propylene with ethylene and / or at least one of the formula CH2=CHR 1 copolymers of α-olefins and mixtures thereof, wherein R 1 The propylene copolymer comprises, by weight (A3.2), at most and preferably from 15% to 40% by weight units derived from ethylene and / or α-olefins, and is either straight-chain or branched C2 to C8 alkyl.

[0047] The polypropylene composition (A3) comprises up to and includes 40% by weight, preferably from 0.1% to 40% by weight, units derived from ethylene and / or α-olefins, based on the weight of (A3), and the amounts of (A3.1) and (A3.2) are based on the total weight of (A3.1) + (A3.2), which is 100%.

[0048] (A4) A polypropylene composition comprising:

[0049] (A4.1) 55% to 80% of a propylene polymer, the propylene polymer being selected from the group consisting of: propylene homopolymers, propylene and ethylene and / or at least one of the formula CH2=CHR 1 copolymers of α-olefins and mixtures thereof, wherein R 1 The copolymer is a straight-chain or branched C2 to C8 alkyl group, comprising up to and including 10% by weight, preferably from 0.1% to 10% by weight, of units derived from ethylene and / or α-olefins, based on (A4.1).

[0050] (A4.2) 20% to 45% by weight of ethylene and at least one of the formula CH2=CHR 1 copolymers of α-olefins and mixtures thereof, wherein R 1The ethylene copolymer comprises, by weight (A4.2), at most and preferably from 10% to 40% by weight of units derived from α-olefins, and is either straight-chain or branched C2 to C8 alkyl.

[0051] The polypropylene composition (A4) comprises, by weight of (A4), at most and including 40% by weight, preferably from 0.1% by weight to 40% by weight, units derived from ethylene and α-olefins, and the amounts of (A4.1) and (A4.2) are based on the total weight of (A4.1) + (A4.2), which is 100% by weight.

[0052] (A5) Their mixture.

[0053] In a preferred embodiment, the propylene copolymer (A1) is selected from a propylene-ethylene-butene-1 terpolymer (A1a), which comprises, by weight of component (A1a), 0.5 wt% to 1.8 wt%, preferably from 0.7 wt% to 1.5 wt%, more preferably from 0.9 wt% to 1.3 wt% of ethylene-derived units and, by weight of component (A1a), 3.5 wt% to 6.5 wt%, preferably from 4.5 wt% to 6.0 wt%, more preferably from 4.8 wt% to 5.8 wt% of butene-1-derived units.

[0054] More preferably, the propylene terpolymer (A1a) has at least one of the following properties:

[0055] -The total amount of units derived from ethylene and butene-1, based on the weight of (A1a), ranges from 5.5% to 7.5% by weight, preferably from 5.7% to 7.1% by weight; and / or

[0056] -Based on (A1a) by weight, the xylene soluble fraction is less than 7.0% by weight, more preferably less than 5.5% by weight; and / or

[0057] - Melting point equal to or higher than 140°C, more preferably from 140°C to 152°C.

[0058] In a further preferred embodiment, the propylene terpolymer (A1a) has all of the above properties.

[0059] In one embodiment, the polymer chain of the propylene terpolymer (A1a) is composed of units derived from propylene, ethylene and butene-1, wherein the propylene terpolymer has all of the above properties.

[0060] Propylene polymers (A1), including propylene terpolymers (A1a), are commercially available and can be obtained by polymerizing relevant monomers in the presence of a highly stereooriented Ziegler-Natta catalyst system, which includes:

[0061] (1) A solid catalyst component comprising a magnesium halide support and a stereoregular internal donor, wherein a Ti compound having at least one Ti-halogen bond is present on the magnesium halide support;

[0062] (2) Optionally, but preferably, it contains an Al co-catalyst; and

[0063] (3) Optionally, but preferably, an additional electron donor compound (external donor).

[0064] The solid catalyst component (1) preferably includes TiCl4 in an amount of Ti ranging from 0.5% to 10% by weight relative to the total weight of the solid catalyst component (1).

[0065] The solid catalyst component (1) includes at least one stereoregular internal electron donor compound selected from monodentate or bidentate organic Lewis bases, preferably selected from esters, ketones, amines, amides, carbamates, carbonates, ethers, nitriles, alkoxysilanes and combinations thereof.

[0066] Preferred donors are esters of phthalic acid, such as those described in EP45977A2 and EP395083A2, particularly diisobutyl phthalate, di-n-butyl phthalate, di-n-octyl phthalate, diphenyl phthalate, benzyl butyl phthalate, and combinations thereof.

[0067] The esters of aliphatic acids may also be selected from esters of malonic acid, such as those described in WO98 / 056830, WO98 / 056833, WO98 / 056834; esters of glutaric acid, such as those disclosed in WO00 / 55215; and esters of succinic acid, such as those disclosed in WO00 / 63261.

[0068] Certain types of diesters are those derived from the esterification of aliphatic or aromatic diols, such as those described in WO2010 / 078494 and USP 7,388,061.

[0069] In some embodiments, the internal donor is selected from 1,3-diethers, such as those described in EP361493, EP728769 and WO02 / 100904.

[0070] Internal donors, particularly specific mixtures of aliphatic or aromatic mono or dicarboxylic esters and 1,3-diethers disclosed in WO07 / 57160 and WO2011 / 061134, can be used as internal donors.

[0071] The preferred magnesium halide support is magnesium dihalide.

[0072] The amount of internal donors fixed on the solid catalyst component (1) relative to magnesium dihalide is 5 mol% to 20 mol%.

[0073] A preferred method for preparing solid catalyst component (1) is described in EP395083A2.

[0074] Catalyst components prepared according to general methods are described, for example, in European patent applications US4,399,054, US4,469,648, WO98 / 44009A1 and EP395083A2.

[0075] In some embodiments, the catalyst system comprises an Al-containing co-catalyst (2) selected from Al-trialkyl, preferably selected from the group consisting of Al-triethyl, Al-triisobutyl and Al-trin-butyl. The Al / Ti weight ratio in the catalyst system is from 1 to 1000, preferably from 20 to 800.

[0076] In the embodiments, the catalyst system includes an additional electron donor compound (3) selected from silicon compounds, ethers, esters, amines, heterocyclic compounds, particularly 2,2,6,6-tetramethylpiperidine, and ketones (external electron donor).

[0077] Preferred silicon compounds are selected from methylcyclohexyldimethoxysilane (C-donor), dicyclopentyldimethoxysilane (D-donor), and mixtures thereof.

[0078] The propylene copolymer (A1) is preferably produced using the polymerization process and reactor described in European Patent EP1012195B1. This polymerization process is carried out in a gas-phase reactor (referred to as a multi-zone circulating reactor (MZCR)) with two interconnected polymerization zones. Polymer particles flow upwards under rapid fluidization or conveying conditions through a first polymerization zone, designated as a “riser,” exiting the riser and entering a second polymerization zone, designated as a “downsink,” where they flow through in a densified form under gravity. A continuous circulation of the polymer is established between the riser and the downsink. Typically, rapid fluidization conditions are established in the riser by feeding a gas mixture comprising the relevant monomers into the riser. The catalyst system is preferably fed into the reactor at any point in the riser.

[0079] In a multi-zone circulating reactor, two polymerization zones with different compositions can be obtained by feeding a gas / liquid stream (barrier stream) into the upper part of the downcomer. The gas / liquid stream acts as a barrier to the gas phase from the riser and establishes an upward net gas flow in the upper part of the downcomer. The established upward gas flow has the effect of preventing the gas mixture present in the riser from entering the downcomer.

[0080] The molecular weight of propylene copolymers is adjusted using chain transfer agents such as hydrogen or ZnEt2.

[0081] Multi-zone circulating reactors are typically operated at temperatures of 50°C to 120°C, preferably 70°C to 90°C, and pressures of 0.5 MPa to 10 MPa, preferably 1.5 MPa to 6 MPa.

[0082] The polypropylene composition (A2) is a blend (extruder or preferably reactor blend) of propylene polymers (A2.1) and (A2.2). In a preferred embodiment, the propylene polymer (A2.1) is a propylene homopolymer, and the propylene polymer (A2.2) is a random propylene-ethylene copolymer.

[0083] Preferably, the polypropylene composition (A2) has at least one of the following properties:

[0084] -Based on the weight of (A2), it includes units derived from ethylene and / or α-olefins, more preferably from ethylene only, in total amounts between 1% and 10% by weight, more preferably between 2% and 5% by weight; and / or

[0085] -Based on the weight of (A2), it has less than 10% by weight of xylene soluble fraction, preferably less than 7% by weight.

[0086] In a further preferred embodiment, the polyolefin composition has all of the above properties.

[0087] The polypropylene composition (A2) is commercially available and can be obtained by melt blending component (A2.1) and component (A2.2) or preferably by polymerizing the relevant monomers in at least two polymerization stages, wherein the second and each subsequent polymerization stage are carried out in the presence of the resulting polymer and the catalyst used in the immediately preceding polymerization stage.

[0088] The monomer is polymerized in the presence of a catalyst selected from metallocene compounds, a highly stereoselective Ziegler-Natta catalyst system as described above, and combinations thereof, preferably in the presence of a highly stereoselective Ziegler-Natta catalyst system.

[0089] The sequential polymerization process for obtaining single components (A2.1) and (A2.2) or for obtaining a polypropylene composition (A2) can be carried out continuously or in batches in the liquid or gas phase.

[0090] Liquid-phase polymerization can be a slurry, solution, or bulk (liquid monomer). The latter is the preferred technique and can be carried out in various types of reactors such as continuous stirred tank reactors, circulating reactors, or plug flow reactors.

[0091] Gas-phase polymerization can be carried out in fluidized bed or stirred fixed bed reactors or in multi-zone circulating reactors, as described in EP1012195.

[0092] The reaction temperature is preferably in the range of 40°C to 90°C, and for processes in the liquid phase, the polymerization pressure is from 3.3 MPa to 4.3 MPa, and for processes in the gas phase, the polymerization pressure is from 0.5 MPa to 3.0 MPa.

[0093] The polypropylene composition (A3) is a blend (extruder or preferably reactor blend) of a crystalline or semi-crystalline propylene polymer matrix (A3.1) and a rubbery propylene copolymer (A3.2).

[0094] The polypropylene composition (A4) is a blend (extruder or preferably reactor blend) of a crystalline or semi-crystalline propylene polymer matrix (A4.1) and a rubbery ethylene / α-olefin copolymer (A4.2).

[0095] In a preferred embodiment, the polypropylene composition (A4) is a polyolefin composition (A4a) comprising:

[0096] (A4.1a) 55% to 80% by weight of a propylene polymer, wherein the propylene polymer is selected from the group consisting of: propylene homopolymers, propylene and ethylene and / or at least one of the formula CH2=CHR 1 copolymers of α-olefins and mixtures thereof, wherein R 1 The copolymer is a straight-chain or branched C2 to C8 alkyl group, comprising up to and including 10% by weight, preferably from 0.1% to 10% by weight, of units derived from ethylene and / or α-olefins, based on (A4.1a), wherein the propylene polymer (A4.1a) has a melt flow rate equal to or greater than 15 g / 10 min, preferably from 15 g / 10 min to 80 g / 10 min, more preferably from 20 g / 10 min to 60 g / 10 min, as measured according to ISO 1133 (230°C, 2.16 kg); and

[0097] (A4.2a) 20% to 45% by weight of ethylene and at least one of the formula CH2=CHR 1 A copolymer of α-olefins, wherein R 1 It is a straight-chain or branched C2 to C8 alkyl group, preferably butene-1, wherein the ethylene copolymer comprises up to and includes 40% by weight, preferably from 10% to 40% by weight, of units derived from α-olefins based on (A4.2a).

[0098] The polypropylene composition (A4a) comprises, by weight, at most and including 40% by weight, preferably from 0.1% to 40% by weight, units derived from ethylene and α-olefins, and the amounts of (A4.1a) and (A4.2a) are based on the total weight of (A4.1a) + (A4.2a), which is 100%.

[0099] Preferably, the polyolefin composition (A4a) comprises 60% to 80% by weight, more preferably 60% to 75% by weight, of a propylene polymer (A4.1a) and 20% to 40% by weight, more preferably 25% to 40% by weight, of an ethylene copolymer (A4.2a), wherein the amounts of (A4.1a) and (A4.2a) are based on the total weight of (A4.1a) + (A4.2a), which is 100%.

[0100] In a preferred embodiment, the polyolefin composition (A4a) has at least one of the following properties:

[0101] - A xylene soluble fraction, by weight of (A4a), ranging from 15% to 35% by weight, preferably from 18% to 35% by weight, more preferably from 18% to 30% by weight; and / or

[0102] - The intrinsic viscosity of the xylene soluble fraction is equal to or less than 1.7 dl / g, preferably from 0.8 dl / g to 1.7 dl / g, more preferably from 1.0 dl / g to 1.6 dl / g.

[0103] In a particularly preferred embodiment, the polyolefin composition (A4a) has all of the above properties.

[0104] In a further preferred embodiment, the polypropylene composition (A4a) comprises:

[0105] (A4.1a) 55% to 80% by weight, preferably 60% to 80% by weight, more preferably 60% to 75% by weight of a propylene-ethylene copolymer, the propylene-ethylene copolymer comprising at most and including 7% by weight, preferably from 0.1% to 7% by weight, more preferably from 0.1% to 5% by weight of ethylene-derived units based on (A4.1a); and

[0106] (A4.2a) 20% to 45% by weight, preferably 20% to 40% by weight, more preferably 25% to 40% by weight of ethylene-butene-1 copolymer, the ethylene-butene-1 copolymer comprising 10% to 40% by weight, preferably 20% to 30% by weight of butene-1 derived units based on (A4.2a).

[0107] The polypropylene composition (A4a) includes:

[0108] -Based on the weight of (A4a), the total amount is at most and includes 40% by weight, preferably from 0.1% to 40% by weight of units derived from ethylene and butene-1;

[0109] - Xylene soluble fraction, from 15% to 35% by weight of (A4a), preferably from 18% to 35% by weight, more preferably from 18% to 30% by weight;

[0110] Furthermore, the polypropylene composition (A4a) has an intrinsic viscosity of the xylene-soluble fraction equal to or less than 1.7 dl / g, preferably from 0.8 dl / g to 1.7 dl / g, and more preferably from 1.0 dl / g to 1.6 dl / g.

[0111] The quantities of (A4.1a) and (A4.2a) are calculated as the total weight of (A4.1a) + (A4.2a), which is 100%.

[0112] Propylene polymer compositions (A3) and (A4), including (A4a), are commercially available and can be obtained by melt blending a matrix and a rubbery component or preferably by polymerizing the relevant monomers in at least two stages, wherein the second and each subsequent polymerization stage are carried out in the presence of the resulting polymer and a catalyst used in the immediately preceding polymerization stage, wherein preferably, component (A3.1) or (A4.1), including (A4.1a), is generated in the first polymerization stage.

[0113] The monomer is polymerized in the presence of a catalyst selected from metallocene compounds, the highly stereoselective Ziegler-Natta catalyst system as described above, and combinations thereof, preferably in the presence of the highly stereoselective Ziegler-Natta catalyst system as described above.

[0114] The polymerization process for obtaining polypropylene compositions (A3) and (A4) (including (A4a)) can be carried out continuously or in batches in the liquid or gas phase.

[0115] Liquid-phase polymerization can be in the form of slurry, solution, or bulk (liquid monomer). The latter is the preferred technique for liquid polymerization and can be carried out in various types of reactors such as continuous stirred tank reactors, circulating reactors, or plug flow reactors.

[0116] Gas-phase polymerization can be carried out in fluidized bed or stirred fixed bed reactors.

[0117] The reaction temperature ranges from 40°C to 90°C, and for liquid-phase processes, the polymerization pressure ranges from 3.3 MPa to 4.3 MPa, while for gas-phase processes, the polymerization pressure ranges from 0.5 MPa to 3.0 MPa.

[0118] The molecular weight of the propylene copolymer obtained during the polymerization stage is adjusted using chain transfer agents such as hydrogen or ZnEt2.

[0119] In all the embodiments described above, the propylene polymer (A) preferably has at least one of the following properties:

[0120] - The melt flow rate (MFR(A)) measured according to ISO 1133 (230°C, 2.16 kg) ranges from 5 g / 10 min to 80 g / 10 min, preferably from 10 g / 10 min to 60 g / 10 min, more preferably from 10 g / 10 min to 50 g / 10 min; and / or

[0121] - A tensile modulus measured according to ISO 527-1 or ISO 527-2 equal to or greater than 900 MPa, preferably in the range of 900 MPa to 2000 MPa, more preferably in the range of 900 MPa to 1500 MPa, and even more preferably in the range of 1000 MPa to 1400 MPa; and / or

[0122] - The yield tensile stress, measured according to ISO 527-1 and ISO 527-2, is equal to or greater than 15 MPa, preferably ranging from 15 MPa to 50 MPa, more preferably from 20 MPa to 40 MPa; and / or

[0123] - The yield tensile strain, measured according to ISO 527-1 and ISO 527-2, ranges from 5% to 35%, preferably from 10% to 30%.

[0124] In a further preferred embodiment, the propylene polymer (A) has all of the above properties.

[0125] In one embodiment, the elastomer component (B) is an ethylene copolymer (B1) selected from those having at least one of the formulas CH2=CHR. 2 ethylene copolymers of α-olefins, wherein R 2 It is a straight-chain or branched C1 to C8 alkyl group, preferably selected from butene-1, hexene-1, octene-1 and combinations thereof.

[0126] The ethylene copolymer (B1) preferably comprises at least 20% by weight, more preferably from 20% to 50% by weight of units derived from α-olefins.

[0127] Ethylene copolymer (B1) can be marketed under the trade name Engage, for example, Engage. TM 8100 or Engage TM Purchased from Dow Chemical (product name 8150) The company sells ethylene copolymers (B1). These copolymers are typically prepared using known processes, preferably solution polymerization in the presence of a metallocene-based catalyst system.

[0128] In a preferred embodiment, the elastomeric component (B) is a saturated or unsaturated styrene or α-methylstyrene block copolymer (B2), preferably comprising up to and including 30% by weight of polystyrene based on (B2), preferably from 10% to 30% by weight, more preferably from 15% to 25% by weight.

[0129] In a further preferred embodiment, the elastomeric component (B) is a styrene block copolymer (B2) selected from the group consisting of: polystyrene-polybutadiene-polystyrene (SBS), polystyrene-poly(ethylene-butene)-polystyrene (SEBS), polystyrene-poly(ethylene-propylene)-polystyrene (SEPS), polystyrene-polyisoprene-polystyrene (SIS), polystyrene-poly(isoprene-butadiene)-polystyrene (SIBS), and mixtures thereof. More preferably, the styrene block copolymer (B2) is polystyrene-poly(ethylene-butene)-polystyrene (SEBS).

[0130] The styrene block copolymer (B2) preferably has at least one of the following properties:

[0131] - The MFR range, measured according to ASTM D1238 (230°C, 2.16 kg), is from 5 g / 10 min to 80 g / 10 min, preferably from 10 g / 10 min to 60 g / 10 min, more preferably from 10 g / 10 min to 30 g / 10 min; and / or

[0132] - The Shore A value measured according to ASTM 2240 (30 seconds) is equal to or less than 70, preferably from 30 to 70, more preferably from 30 to 60.

[0133] In a further preferred embodiment, the styrene block copolymer has all of the above properties.

[0134] Styrene or α-methylstyrene block copolymers (B2) are prepared by ionic polymerization of the relevant monomers and can be marketed under the trade name Kraton. TM Acquired through commercial purchase and sold by KETEN Polymers.

[0135] The glass fiber (C) included in the polyolefin composition preferably has a diameter ranging from 5 μm to 20 μm, more preferably from 8 μm to 15 μm, and a length equal to or less than 10 mm, preferably from 0.1 mm to 10 mm, more preferably from 1 mm to 8 mm, more preferably from 2 mm to 7 mm, and even more preferably from 3 mm to 6 mm.

[0136] Compatibilizer (D) is optionally, but preferably, included in the polyolefin composition to increase the compatibility of the glass fiber with components (A) and (B). Compatibilizer (D) is preferably a modified olefin polymer functionalized with a polar compound and optionally with a low molecular weight compound having a reactive polar group. Preferably, the modified olefin polymer is selected from polyethylene, polypropylene, and mixtures thereof.

[0137] The modified olefin polymers are selected from graft copolymers, block copolymers, and mixtures thereof.

[0138] Preferably, the modified polymer is functionalized with groups derived from polar compounds, including but not limited to acid anhydrides, carboxylic acids, carboxylic acid derivatives, primary and secondary amines, hydroxyl compounds, azoline, epoxides, ionic compounds, and combinations thereof. Specific examples of such polar compounds are unsaturated cyclic anhydrides, their aliphatic diesters, and diacid derivatives.

[0139] Preferably, the compatibilizer (D) is a polyolefin functionalized with a compound selected from the group consisting of: maleic anhydride, C1 to C10 linear or branched dialkyl maleate, C1 to C10 linear or branched dialkyl fumarate, itaconic anhydride, C1 to C10 linear or branched itaconic acid, dialkyl ester, maleic acid, fumaric acid, itaconic acid, and mixtures thereof.

[0140] In a preferred embodiment, the compatibilizer (D) is maleic anhydride-grafted polyethylene and / or polypropylene (MAH-g-PP and / or MAH-g-PE).

[0141] In a further preferred embodiment, the compatibilizer (D) is maleic anhydride-grafted polyethylene and / or polypropylene, which has at least one of the following properties:

[0142] -Based on component (B), maleic anhydride grafting levels equal to or greater than 0.5% by weight, more preferably from 0.5% by weight to 3.0% by weight, even more preferably from 0.75% to 2.0% by weight; and / or

[0143] - The melt flow rate range determined according to method ISO 1133 (190°C, 2.16 kg) is equal to or greater than 80 g / 10 min, preferably from 80 g / 10 min to 200 g / 10 min.

[0144] In a preferred embodiment, the maleic anhydride-grafted polyethylene and / or polypropylene have all of the above properties.

[0145] Modified polymers are known in the art and can be produced by functionalization processes carried out in solution, in the solid state, or preferably in the molten state, for example by reactive extrusion of polymers in the presence of graft compounds and free radical initiators. For example, maleic anhydride functionalization of polypropylene and / or polyethylene is described in EP0572028A1.

[0146] An example of a modified polyolefin suitable for use as a compatibilizer is Amplify, a product of The Dow Chemical Company. TM TY, ExxonMobil Chemical Company's Exxelor TM BYK (Altana Group) TPPP, Polyram Group And Chemtura and their combinations.

[0147] In a preferred embodiment, the polyolefin composition further comprises up to and including 1.0% by weight, preferably from 0.01% by weight to 1.0% by weight, a clarifying agent and / or a nucleating agent (E), wherein the amount of (E) is based on the total weight of (A)+(B)+(C)+(D)+(E), which is 100%. The polyolefin composition including the nucleating agent and / or clarifying agent (E) has a lower light absorption.

[0148] Preferably, the polyolefin composition optionally includes up to 3.0% by weight of at least one additional additive selected from the group consisting of: antistatic agents, antioxidants, light stabilizers, slip agents, acid stabilizers, melt stabilizers, and combinations thereof, wherein the amount of the additional additive is based on the total weight of the polyolefin composition including the additional additive.

[0149] The polyolefin composition preferably has at least one of the following properties:

[0150] - The flexural modulus measured on injection-molded specimens obtained according to EN ISO 20753 (Type B2) according to ISO 178 / A:2019-04 is equal to or greater than 800 MPa, preferably equal to or greater than 1000 MPa, more preferably equal to or greater than 1100 MPa; and / or

[0151] -Charpy impact strength measured on injection-molded specimens obtained according to EN ISO 20753 (Type B2) according to ISO 179 / -1eA:2010-11 (notched, 23°C) ranges from 10 to 45 kJ / m. 2 Preferred values ​​are from 15 to 35 kJ / m2 ; and / or

[0152] Charpy impact strength measured on injection-molded specimens obtained according to EN ISO 20753 (Type B2) according to ISO 179 / -1eA:2010-11 (notched, -30°C) ranges from 1 to 10 kJ / m. 2 Preferably from 1.5 to 8 kJ / m 2 ; and / or

[0153] - The shrinkage rate in the longitudinal direction, measured according to the method described in the experimental section, is less than 0.70%, preferably less than 0.50%; and / or

[0154] - The shrinkage rate in the transverse direction, measured according to the methods described in the experimental section, is less than 1.00%, preferably less than 0.85%; and / or

[0155] - The haze on a 1 mm thick plate, measured according to the method described in the experimental section, is equal to or greater than 85%, preferably equal to or greater than 95%; and / or

[0156] - The absorbance ABS1 measured at any wavelength from 380 nm to 780 nm on a 100 μm thick film according to the method described in the experimental section is less than 0.70, preferably less than 0.60; and / or

[0157] - Absorbance ABS2(380) and / or ABS2(780), preferably both, measured at 380 nm and 780 nm on a 1 mm thick plate obtained according to the method described in the experimental section, equal to or less than 1.6; and / or

[0158] - The change in absorbance ΔABS2 measured on a 1 mm thick plate obtained according to the method described in the experimental section is equal to or less than 0.4, preferably equal to or less than 0.3, wherein the change in absorbance is determined by the following equation:

[0159] ΔABS2=|ABS2(380)-ABS2(780)|

[0160] Wherein ABS2(380) is the absorbance measured at a wavelength of 380 nm and ABS2(780) is the absorbance measured at 780 nm.

[0161] In a preferred embodiment, the polyolefin composition has all of the above properties.

[0162] The polyolefin composition is preferably obtained by melting and blending components (A), (B), (C) and optionally (D) and (E) in a conventional melt blending apparatus, preferably a twin-screw extruder, to form a molten polyolefin composition, and then pushing the molten polyolefin composition through a die and curing the molten polyolefin composition.

[0163] In one embodiment, the polyolefin composition includes at most 10% by weight of at least one organic or inorganic pigment. The above optical properties refer to polyolefin compositions excluding pigments.

[0164] In one embodiment, the cover for the light source according to this disclosure is composed of the polyolefin composition described above.

[0165] The polyolefin composition described above has a balance of optical and mechanical properties, making it suitable for use as a cover for light sources.

[0166] Therefore, this disclosure also relates to the use of the polyolefin compositions described above as coverings for light sources.

[0167] A method for covering a light source is also disclosed, the method comprising:

[0168] (a) Molding the polyolefin composition as described above to obtain a covering; and

[0169] (b) Position the covering in front of the light source so as to at least partially block the light.

[0170] In a further aspect, this disclosure relates to a process for manufacturing a cover for a light source, the process comprising using a polyolefin composition, wherein the process preferably comprises a step (i) of shaping the polyolefin composition by injection molding, cast extrusion, profile extrusion, rotational molding, blow molding or deep drawing.

[0171] In one embodiment, the cover for the light source is a sheet with a thickness of up to 30 mm, preferably ranging from 1 mm to 10 mm.

[0172] The features describing the subject matter of this disclosure are not indivisibly linked to each other. Therefore, a preference for a particular level of a feature does not necessarily involve a preference for the same level of the remaining features of the same or different components. The intention of this disclosure is that any preferred feature range of components (A) to (E) from which the polyolefin blend is obtained can be combined independently of preference levels, and components (A) to (E) can be combined with any possible additional components and their features described in this disclosure.

[0173] Example

[0174] The following examples are merely illustrative and are not intended to limit the scope of this disclosure in any way.

[0175] Characterization methods

[0176] The following methods are used to determine the characteristics indicated in the specification, claims, and examples.

[0177] Melt flow rate: determined according to method ISO 1133 (for thermoplastic polyolefins, 230°C, 2.16 kg; for compatibilizers, 190°C / 2.16 kg).

[0178] Solubility in xylene at 25°C: 2.5 g of the polymer sample and 250 ml of xylene were introduced into a glass flask equipped with a refrigerator and a magnetic stirrer. The temperature was raised to 135°C over 30 minutes. The resulting clear solution was kept under reflux and stirred for an additional 30 minutes. The solution was cooled in two stages. In the first stage, the temperature was lowered to 100°C in air with stirring for 10 to 15 minutes. In the second stage, the flask was transferred to a temperature-controlled water bath at 25°C for 30 minutes. The temperature was lowered to 25°C without stirring for the first 20 minutes and maintained at 25°C with stirring for the last 10 minutes. The resulting solid was filtered through rapid filter paper (e.g., Whatman filter paper grade 4 or 541). 100 ml of the filtered solution (S1) was poured into a pre-weighed aluminum container and heated to 140°C on a hot plate under a nitrogen stream to remove the solvent by evaporation. The container was then kept under vacuum in an oven at 80°C until constant weight was achieved. Then the amount of polymer soluble in xylene at 25°C was calculated. XS(I) and XS were determined experimentally. A Value. Fractions (XS) of component (B) soluble in xylene at 25°C. B It can be calculated using the following formula:

[0179] XS=W(A)×(XS A )+W(B)×(XS B )

[0180] Where W(A) and W(B) are the relative amounts of components (A) and (B), respectively, and W(A) + W(B) = 1.

[0181] C2 content in propylene-ethylene copolymer (II): 13 C10 NMR spectra were acquired on a Bruker AV-600 spectrometer equipped with a cryoprobe, operated at 160.91 MHz in Fourier transform mode at 120 °C. P ββThe carbon peak (nominated according to C.J. Carman, R.A. Harrington, and C.E. Wilkes, *Macromolecules*, 10, 3, 536 (1977)) at 2.8 ppm was used as an internal reference. The sample was dissolved in 1,1,2,2-tetrachloroethane-d2 at 120 °C at a concentration of 8% wt / v. Each spectrum was acquired using a 90° pulse, with a 15-second delay between pulses and CPD used for removal. 1 H- 13 C-coupling. 512 transients were stored in 32K data points using a spectral window of 9000 Hz. Spectral assignment, triplet distribution, and compositional evaluation were performed according to Kakugo [M. Kakugo, Y. Naito, K. Mizunuma, and T. Miyatake, *Macromolecules*, 16, 4, 1160 (1982)]. Due to the low amount of propylene inserted as a regiorandom unit, [M. Kakugo, Y. Naito, K. Mizunuma, and T. Miyatake, *Macromolecules*, 16, 4, 1160 (1982)]. 4 [1160 (1982)] Ethylene content was calculated using only triplet sequences with P inserted as a regular unit.

[0182] PPP = 100T ββ / S

[0183] PPE = 100T βδ / S

[0184] EPE = 100T δδ / S

[0185] PEP = 100S ββ / S

[0186] PEE = 100S βδ / S

[0187] EEE = 100(0.25S) γδ +0.5S δδ ) / S

[0188] Where S = T ββ +T βδ +T δδ +S ββ +S βδ +0.25S γδ +0.5S δδ

[0189] Yield tensile modulus, stress and strain: determined on specimens according to ISO 20753-A1:2018-10 according to methods ISO 527-1, ISO 527-2:2019.

[0190] Flexural modulus: determined according to ISO 178 / A:2019-04 on a B2 type injection molded specimen according to ISO 20753.

[0191] Charpy impact strength: measured at 23°C and -30°C on a B2 type injection molded sample according to ISO 20753, according to ISO 1791eA.

[0192] Heat shrinkage rate: For molding a 195×100×2.5mm sheet in a Krauss Maffei KM250 / 1000C2 injection molding machine (250 tons required force) under the following injection conditions:

[0193] - Melting temperature: 220℃;

[0194] - Mold temperature: 35℃;

[0195] - Injection time: 3.6 seconds;

[0196] - Duration: 30 seconds;

[0197] - Screw diameter: 55mm

[0198] The plate was annealed at 23°C for 48 hours. Then, the length (L) and width (W) of the plate were measured. The heat shrinkage rate was calculated using the following formula:

[0199] Longitudinal shrinkage rate = [(195-L) / 195]×100

[0200] Lateral shrinkage rate = [(100-W) / 100]×100

[0201] in

[0202] 195 and L are the dimensions of the mold and the measured dimensions of the plate along the flow direction, respectively, in mm; and

[0203] 100 and W are the dimensions of the mold and the transverse plate along the flow direction, respectively, in mm.

[0204] The values ​​indicated in the table are the arithmetic mean of the measurements taken from the five plates.

[0205] Haze: This method, according to ASTM D1003 (uncompensated method), determines the percentage of transmitted light that deviates from the incident beam by forward scattering as it passes through the specimen. Light deviating more than 2.5° is considered haze. Haze values ​​are determined using a haze meter such as the BYK-Gardner Hazegard Plus or an equivalent instrument with CIE luminescent C and integrating sphere geometry according to ASTM D1003. Prior to testing, a 1 mm thick plate is acclimatized for 24 hours at 23 ± 2 °C and 50 ± 10% humidity. The plate is placed in contact with the haze port and the measurement is taken at the center of the test specimen. The haze value is automatically calculated by the testing instrument based on the following formula:

[0206] Haze [%] = T d / T t ×100

[0207] Where Td is diffuse transmittance and Tt is total transmittance.

[0208] Absorbency: Under the following conditions, Evolution TM The absorbance in the UV-VIS spectrum was measured directly on a 100 μm thick film and a 1 mm thick injection-molded plate using a 220 spectrophotometer (via Thermo Fischer Scientific).

[0209] - Scan: 380nm to 800nm

[0210] -Speed: 200nm / min

[0211] - Slit: 2nm

[0212] - Data interval: 1nm.

[0213] Total light transmittance: This method determines the percentage of transmitted light that passes through the specimen. A haze meter, such as the Hazegard XL-211 or an equivalent instrument, and integrating sphere geometry are used to determine the transmittance value to collect the scattered light. The collected light is measured using a photodetector whose spectral sensitivity has been modified by filtering to approximate the 1931 CIE standard observer response to source C. Prior to testing, a 3 mm thick plate is acclimatized at 23 ± 2 °C and 50 ± 10% humidity for at least 48 hours. After calibrating the equipment to adjust to 100% transmittance, the plate is placed in contact with the haze / transmittance port and the measurement is taken at the center of the test specimen. The total light transmittance value is automatically calculated by the testing instrument.

[0214] Injection molding sheets for determining haze and absorption: 1mm thick sheets are obtained using a NegriBossi VE70 injection molding machine operated under the following conditions:

[0215]

[0216]

[0217] Injection molded sheets used for light transmittance determination: 3mm thick sheets were obtained using a Krauss Maffei CX160-750 injection molding machine (160 tons required force) operating under the following conditions:

[0218]

[0219] Membrane preparation: The 100 μm thick membrane for optical measurements was produced by compression molding using a constant thickness membrane manufacturing machine (29 mm in diameter) supplied by Specac Ltd., which is equipped with a suitable ring / separator and a Carver press operating at 190°C and 2 tons of pressure.

[0220] raw material:

[0221] PP1: A propylene-ethylene-butene-1 terpolymer was prepared according to the polymerization process described in Example 1 of WO2014 / 198459, containing 1.1 wt% ethylene units and 5.3 wt% butene-1 units, and having 5.0 wt% xylene-soluble fraction. The polymer particles obtained from the reactor were molten with 0.4 wt% of... 8000, 0.05% by weight calcium stearate, 0.1% by weight glyceryl monostearate (GMS 90), 0.1% by weight 168% and 0.05% by weight of antioxidant were mixed. The extruder was operated under a nitrogen atmosphere at a rotation speed of 250 rpm and a temperature of 200°C to 250°C. The properties of the obtained material are reported in Table 1.

[0222] PP2: A polypropylene composition comprising a propylene-ethylene random copolymer containing 3.0 wt% ethylene units, the composition having 6 wt% xylene-soluble fraction. The polypropylene composition is produced in two circulating reactors according to the polymerization process described in Example 1 of WO2006 / 018813. Polymer particles obtained from the reactors are mixed in a molten state with 0.18 wt% DMDBS, 0.05 wt% calcium stearate, 0.05 wt% glyceryl monostearate (GMS 90), and 0.1 wt%... 168% and 0.05% by weight of antioxidant were mixed. The extruder was operated under a nitrogen atmosphere at a rotation speed of 250 rpm and a temperature of 200°C to 250°C. The properties of the obtained material are reported in Table 1.

[0223] PP3: A polypropylene composition comprising 31 wt% of a propylene-ethylene copolymer having an MFR (ISO 1133; 230°C, 2.16 kg) of 39 g / 10 min and 69 wt% of an ethylene-butene 1 copolymer. The polypropylene composition has an intrinsic viscosity of 20 wt% xylene-soluble fraction and 1.45 dl / g xylene-soluble fraction. The composition comprises 24 wt% ethylene-derived units and 7.2 wt% butene-1-derived units, and is obtained according to the polymerization process described in Examples 1 to 3 of WO2004 / 003073. Polymer particles obtained from the reactor cascade are mixed in a molten state with 0.18 wt% DMDBS, 0.05 wt% calcium stearate, 0.05 wt% glyceryl monostearate (GMS90), and 0.1 wt%... 168% and 0.05% by weight of antioxidant were mixed. The extruder was operated under a nitrogen atmosphere at a rotation speed of 250 rpm and a temperature of 200°C to 250°C. The properties of the obtained material are reported in Table 1.

[0224] Table 1

[0225] MFR (230℃ / 2.16Kg) g / 10min 40 11 20 Tensile modulus MPa 1250 1150 1150 Yield tensile stress MPa 30 30 23 Yield tensile strain ％ 11 14 13

[0226] Moplen HF501N is a propylene homopolymer from LyondellBasell with a melt flow rate of 12 g / 10 min (ISO 1133; 230 °C / 2.16 kg) and a tensile modulus of 1550 MPa (ISO 527-1, ISO 527-2:2019).

[0227] Kraton from Kraton Company TM G1643 V is a linear styrene triblock copolymer based on styrene and ethylene / butene containing 20% ​​by weight of polystyrene, with an MFR (ASTM D1238; 230°C, 2.16 kg) of 19 g / 10 min and a Shore A value (ASTM D2240, 30 seconds) of 52.

[0228] Kraton G1657 V from Kraton Corporation is a linear triblock copolymer of styrene and ethylene / butene, containing 13% by weight of polystyrene, with an MFR (ASTM D1238; 230°C and 5 kg) of 22 g / 10 min and a Shore A value (ASTM D2240, 10 seconds) of 47.

[0229] GF EC10636: From Johns Manville 636 is a chopped E-glass fiber with a fiber diameter of 10 μm and a chopped filament length of 4 mm.

[0230] From Polyram Plastic Industries LTD 1101 is a maleic anhydride-modified polypropylene compound with a maleic anhydride content (FTIR) of 1% by weight and a melt flow index (ISO 1133, 190℃ / 2.16Kg) of 170g / 10min.

[0231] DMDBS, 1,3:2,4-bis(3,4-dimethyldibenzyl)sorbitol, Millad 3988, supplied by Milliken Chemical.

[0232] 8000, a clarifying agent supplied by Milliken Chemical Company.

[0233] 168, a processing stabilizer supplied by BASF.

[0234] Compare instances CE1 to CE2 and instances E3 to E5

[0235] PP1 was melt-blended with the components reported in Table 2 in a Werner & Pfleiderer Doppelschneckenextruder 40mm twin-screw extruder with a screw length-to-diameter ratio of 48, and operated under a nitrogen atmosphere under the following conditions:

[0236] Screw speed: 300 rpm;

[0237] Melting temperature: from 190℃ to 200℃.

[0238] The mechanical and optical properties of the polypropylene composition were tested, and the results are shown in Table 2.

[0239] Table 2

[0240]

[0241] Comparison of CE6 to CE7 and CE8 to E10

[0242] Using the same extruder and extrusion conditions as in the previous examples, PP2 was melt-blended with the components reported in Table 3.

[0243] The mechanical and optical properties of the polypropylene composition were tested, and the results are shown in Table 3.

[0244] Table 3

[0245]

[0246]

[0247] Compare instances CE11 to CE12 and instances E13 to E15

[0248] Using the same extruder and extrusion conditions as in the previous examples, PP3 was melt-blended with the components reported in Table 4. The mechanical and optical properties of the polypropylene compositions were tested, and the results are shown in Table 4.

[0249] Table 4

[0250]

[0251]

[0252] For the compositions of comparative examples CE11 to CE12 and examples E13 to E15, the absorbance of a 100 μm thick film was measured at wavelengths from 280 nm to 990 nm (ABS1). The absorbance as a function of wavelength is plotted in... Figure 1 The diagram in the middle is shown.

[0253] Example E16

[0254] The mechanical properties and total light transmittance values ​​of the polyolefin compositions according to this disclosure, measured on a 3 mm thick plate, are reported in Table 5.

[0255] Table 5

[0256]

Claims

1. A cover for a light source comprising a polyolefin composition, said polyolefin composition comprising: A, 50% to 80% by weight of a propylene polymer, said propylene polymer comprising from 0.1% to 40% by weight of ethylene and / or at least one of the formula CH2=CHR based on the weight of A. 1 The unit of α-olefin, wherein R 1 The propylene polymer is a straight-chain or branched C2 to C8 alkyl group, wherein the propylene polymer is selected from the group consisting of: A1, propylene with ethylene and / or at least one of the formula CH2=CHR 1 copolymers of α-olefins, wherein R 1 The copolymer is a straight-chain or branched C2 to C8 alkyl group, comprising from 0.1% to 8.5% by weight of units derived from ethylene and / or the α-olefin, based on the weight of A1. A2, a polypropylene composition, wherein the polypropylene composition comprises: A2.1, 25% to 65% by weight of propylene homopolymer or propylene with ethylene and / or at least one of the formula CH2=CHR 1 A copolymer of α-olefins, wherein R 1 The copolymer is a straight-chain or branched C2 to C8 alkyl group, comprising from 0.1% to 2% by weight of units derived from ethylene and / or the α-olefin, based on A2.1; and A2.2, 35% to 75% by weight of propylene with ethylene and / or at least one of the formula CH2=CHR 1 copolymers of α-olefins, wherein R 1 The copolymer is a straight-chain or branched C2 to C8 alkyl group, comprising from 0.1% to 15% by weight of units derived from ethylene and / or the α-olefin, based on A2.

2. The quantities of A2.1 and A2.2 are calculated as the total weight of A2.1 + A2.2; A4, a polypropylene composition, wherein the polypropylene composition comprises: A4.1, 55% to 80% of a propylene polymer, said propylene polymer being selected from the group consisting of: propylene homopolymers, propylene and ethylene and / or at least one of the formula CH2=CHR. 1 copolymers of α-olefins and mixtures thereof, wherein R 1 The copolymer is a straight-chain or branched C2 to C8 alkyl group, comprising from 0.1% to 10% by weight of units derived from ethylene and / or the α-olefin, based on A4.

1. A4.2, 20% to 45% by weight of ethylene with at least one of the formula CH2=CHR 1 copolymers of α-olefins and mixtures thereof, wherein R 1 The ethylene copolymer is a straight-chain or branched C2 to C8 alkyl group, comprising from 10% to 40% by weight of units derived from the α-olefin, based on A4.

2. The polypropylene composition A4 comprises units derived from ethylene and the α-olefin in a total amount from 0.1% to 40% by weight of A4, and the amounts of A4.1 and A4.2 are based on the total weight of A4.1 + A4.2; and A5, a mixture of them; B, 15% to 35% by weight of an elastomer component, said elastomer component being selected from: B2, a saturated or unsaturated styrene or α-methylstyrene block copolymer, wherein the block copolymer comprises from 10% to 30% by weight of polystyrene based on the weight of B2. C, 5% to 30% by weight of glass fiber, and D, 0% to 5.0% by weight of compatibilizer, The quantities of A, B, C, and D are calculated as the total weight of A+B+C+D.

2. The covering for a light source according to claim 1, wherein the propylene copolymer A is selected from the group consisting of: A1a, a propylene-ethylene-butene-1 terpolymer, said propylene-ethylene-butene-1 terpolymer comprising 0.5 wt% to 1.8 wt% of ethylene-derived units based on the weight of component A1a and 3.5 wt% to 6.5 wt% of butene-1-derived units based on the weight of A1a, wherein said propylene-ethylene-butene-1 terpolymer has at least one of the following properties: -Based on the weight stated in A1a, the total amount of units derived from ethylene and butene-1 ranges from 5.5% by weight to 7.5% by weight; and / or - The melt flow rate was measured according to ISO 1133, 230°C, 2.16 kg, ranging from 20 g / 10 min to 80 g / 10 min; and / or -The xylene soluble fraction is less than 7.0% by weight, based on the weight stated in A1a; and / or - Melting point ranges from 140°C to 152°C; A4a, a polyolefin composition, said polyolefin composition comprising: A4.1a, 55% to 80% by weight of a propylene polymer, said propylene polymer being selected from the group consisting of: propylene homopolymers, propylene and ethylene and / or at least one of the formula CH2=CHR. 1 copolymers of α-olefins and mixtures thereof, wherein R 1 The copolymer is a straight-chain or branched C2 to C8 alkyl group, comprising from 0.1% to 10% by weight of units derived from ethylene and / or the α-olefin, based on the weight of A4.1a, wherein the propylene polymer A4.1a has a melt flow rate from 15 g / 10 min to 80 g / 10 min as measured according to ISO 1133, 230°C, 2.16 kg. A4.2a, 20% to 45% by weight of ethylene and at least one of the formula CH2=CHR 1 copolymers of α-olefins, wherein R 1 It is a straight-chain or branched C2 to C8 alkyl group, wherein the ethylene copolymer comprises from 10% to 40% by weight of units derived from the α-olefin, based on A4.2a; The polypropylene composition A4a comprises units derived from ethylene and the α-olefin in a total amount from 0.1% to 40% by weight of A4a, and the amounts of A4.1a and A4.2a are based on the total weight of A4.1a + A4.2a. as well as A5a, and their mixture.

3. The cover for a light source according to claim 1, wherein the elastomeric component B is a styrene block copolymer B2 selected from the group consisting of: polystyrene-polybutadiene-polystyrene SBS, polystyrene-polyethylene-butene-polystyrene SEBS, polystyrene-polyethylene-propylene-polystyrene SEPS, polystyrene-polyisoprene-polystyrene SIS, polystyrene-polyisoprene-butadiene-polystyrene SIBS, and mixtures thereof.

4. The cover for a light source according to claim 1, wherein the glass fiber C has a diameter ranging from 5 µm to 20 µm and a length ranging from 0.1 mm to 10 mm.

5. The cover for a light source according to claim 1, wherein the compatibilizer D is a polyolefin functionalized with a compound selected from the group consisting of: maleic anhydride, C1 to C10 straight-chain or branched dialkyl maleate, C1 to C10 straight-chain or branched dialkyl fumarate, itaconic anhydride, C1 to C10 straight-chain or branched itaconic acid, dialkyl ester, maleic acid, fumaric acid, itaconic acid, and mixtures thereof.

6. The cover for a light source according to claim 1, wherein R 1 Choose from the following groups: butene-1, hexene-1, 4-methyl-1-pentene, octene-1 and combinations thereof.

7. A polyolefin composition comprising: A, 50% to 80% by weight of a propylene copolymer, wherein the propylene copolymer is selected from the group consisting of: A1, propylene with ethylene and / or at least one of the formula CH2=CHR 1 copolymers of α-olefins, wherein R 1 The copolymer is a straight-chain or branched C2 to C8 alkyl group, comprising from 0.1% to 8.5% by weight of units derived from ethylene and / or the α-olefin, based on the weight of A1. A2, a polypropylene composition, wherein the polypropylene composition comprises: A2.1, 25% to 65% by weight of propylene homopolymer or propylene with ethylene and / or at least one of the formula CH2=CHR 1 A copolymer of α-olefins, wherein R 1 The copolymer is a straight-chain or branched C2 to C8 alkyl group, comprising from 0.1% to 2% by weight of units derived from ethylene and / or the α-olefin, based on A2.1; and A2.2, 35% to 75% by weight of propylene with ethylene and / or at least one of the formula CH2=CHR 1 copolymers of α-olefins, wherein R 1 The copolymer is a straight-chain or branched C2 to C8 alkyl group, comprising from 0.1% to 15% by weight of units derived from ethylene and / or the α-olefin, based on A2.

2. The quantities of A2.1 and A2.2 are calculated as the total weight of A2.1 + A2.2; A4, a polypropylene composition, wherein the polypropylene composition comprises: A4.1, 55% to 80% of a propylene polymer, said propylene polymer being selected from the group consisting of: propylene homopolymers, propylene and ethylene and / or at least one of the formula CH2=CHR. 1 copolymers of α-olefins and mixtures thereof, wherein R 1 The copolymer is a straight-chain or branched C2 to C8 alkyl group, comprising from 0.1% to 10% by weight of units derived from ethylene and / or the α-olefin, based on A4.

1. A4.2, 20% to 45% by weight of ethylene with at least one of the formula CH2=CHR 1 copolymers of α-olefins and mixtures thereof, wherein R 1 The ethylene copolymer is a straight-chain or branched C2 to C8 alkyl group, comprising from 10% to 40% by weight of units derived from the α-olefin, based on A4.

2. The polypropylene composition A4 comprises from 0.1% to 40% by weight of units derived from the α-olefin, based on the weight of A4, and wherein the amounts of A4.1 and A4.2 are based on the total weight of A4.1 + A4.2; and A5, a mixture of them; B, 15% to 35% by weight of saturated or unsaturated styrene or α-methylstyrene block copolymers, wherein the styrene block copolymers comprise 10% to 30% by weight of polystyrene based on component B2. C, 5% to 30% by weight of glass fiber, and D, 0% to 5.0% by weight of compatibilizer, The quantities of A, B, C, and D are calculated based on the total weight of A+B+C+D, where the total weight is 100%.

8. The polyolefin composition of claim 7, wherein the propylene copolymer A is as defined in claim 2.

9. The polyolefin composition according to claim 7, wherein component B is a styrene block copolymer B2 selected from the group consisting of: polystyrene-polybutadiene-polystyrene SBS, polystyrene-polyethylene-butene-polystyrene SEBS, polystyrene-polyethylene-propylene-polystyrene SEPS, polystyrene-polyisoprene-polystyrene SIS, polystyrene-polyisoprene-butadiene-polystyrene SIBS, and mixtures thereof.

10. The polyolefin composition of claim 7, wherein the glass fiber C has a diameter ranging from 5 µm to 20 µm and a length ranging from 0.1 mm to 10 mm.

11. The polyolefin composition according to claim 7, wherein the compatibilizer D is a polyolefin functionalized with a compound selected from the group consisting of: maleic anhydride, C1 to C10 linear or branched dialkyl maleate, C1 to C10 linear or branched dialkyl fumarate, itaconic anhydride, C1 to C10 linear or branched itaconic acid, dialkyl ester, maleic acid, fumaric acid, itaconic acid, and mixtures thereof.

12. A process for manufacturing a cover for a light source, comprising using the polyolefin composition as defined in claim 1.

13. The process of claim 12, comprising step i of forming the polyolefin composition as defined in claim 1 by injection molding, cast extrusion, profile extrusion, rotational molding, blow molding or deep drawing.

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