Polyolefin composition with high transparency

Abstract

The present disclosure relates to a polyolefin composition having high transparency comprising: A) a propylene polymer, or a heterophasic polyolefin composition comprising said propylene polymer and an ethylene copolymer; B) from 0.01 wt% to 2 wt% of a butene-1 polymer; and C) a clarifying agent; wherein the amount of C) is relative to the total weight of A) + B) + C).

Description

Technical Field

[0001] This disclosure relates to a polyolefin composition having low haze and therefore high transparency, also known as optical clarity, comprising a propylene polymer, or a multiphase polyolefin composition comprising said propylene polymer, a clarifying agent, and a small amount of butene-1 polymer.

[0002] Compared to polyolefin compositions containing only clarifying agents, the incorporation of the butene-1 polymer allows for improved transparency. Background Technology

[0003] Crystalline polyolefins, including polypropylene, are widely used in the industrial production of a very wide range of finished or semi-finished products, such as injection-molded, extruded or blow-molded products, like containers, bottles, sheets, films and fibers.

[0004] In many applications, such as injection-molded, blow-molded, and extruded products used for medical purposes and packaging, high transparency is often desired.

[0005] As reported, for example, in WO2016 / 025326, high transparency in propylene polymers can be achieved by adding clarifying agents.

[0006] When propylene polymers are melted, shaped, and cooled to obtain the final product, clarifying agents typically have a crystal nucleation effect on the propylene polymers.

[0007] Therefore, the size of the crystal is reduced and light scattering is decreased, even though some residual haze still remains.

[0008] It has now been found that the haze of polyolefin compositions comprising propylene polymers and clarifying agents can be further reduced by adding a small amount of butene-1 polymer. Summary of the Invention

[0009] Therefore, this disclosure provides a polyolefin composition comprising:

[0010] A) A propylene polymer, or a multiphase polyolefin composition comprising the propylene polymer and an ethylene copolymer;

[0011] B) From 0.01 wt% to 2 wt%, preferably from 0.015 wt% to 1.5 wt%, more preferably from 0.02 wt% to 0.5 wt%, most preferably from 0.02 wt% to 0.3 wt%, particularly from 0.02 wt% to 0.2 wt% of butene-1 polymer; and

[0012] C) Clarifying agent;

[0013] The quantity of C) is relative to the total weight of A) + B) + C).

[0014] In addition to enhanced transparency, the composition also has good mechanical properties. Detailed Implementation

[0015] As previously mentioned, the addition of butene-1 polymer B) has the effect of reducing the haze of polyolefin compositions containing components A) and C).

[0016] Therefore, this disclosure also provides the use of butene-1 polymer B) to reduce the haze of a polyolefin composition comprising:

[0017] A) a propylene polymer, or a multiphase polyolefin composition comprising the propylene polymer and an ethylene copolymer; and

[0018] C) Clarifying agent;

[0019] The butene-1 polymer B) is added to the polyolefin composition in an amount from 0.01 wt% to 2 wt%, preferably from 0.015 wt% to 1.5 wt%, more preferably from 0.02 wt% to 0.5 wt%, most preferably from 0.02 wt% to 0.3 wt%, and particularly from 0.02 wt% to 0.2 wt%, relative to the total weight of A)+B)+C).

[0020] As used herein, the term "propylene polymer" includes polymers selected from propylene homopolymers, propylene copolymers, and especially random copolymers and mixtures thereof.

[0021] Similarly, as used herein, the term "butene-1 polymer" includes polymers selected from butene-1 homopolymers, butene-1 copolymers, and mixtures thereof.

[0022] In the polyolefin composition of the present invention, when A) is a propylene copolymer, it contains one or more comonomers preferably selected from ethylene and CH2=CHRα-olefins, wherein R is a C2-C8 alkyl radical, particularly butene-1, pentene-1, 4-methyl-pentene-1, hexene-1 and octene-1.

[0023] Ethylene, butene-1, and hexene-1 are preferred.

[0024] When B) is a butene copolymer, it contains one or more comonomers preferably selected from ethylene, propylene and CH2=CHRα-olefins, wherein R is a C3-C8 alkyl radical, particularly pentene-1, 4-methyl-pentene-1, hexene-1 and octene-1.

[0025] Ethylene, propylene, and hexene-1 are preferred.

[0026] As can be clearly seen from the above definition, the term "copolymer" includes polymers containing more than one comonomer.

[0027] When selected from propylene homopolymers and copolymers, other preferred features of propylene polymer A) are:

[0028] - When A) is a copolymer, the content of comonomer is from 0.5 to 15% by weight, more preferably from 1 to 12% by weight, and particularly from 0.5 to 6% by weight when the comonomer is ethylene or hexene-1;

[0029] - The polydispersity index (PI) is equal to or greater than 4, specifically from 4 to 20, more preferably from 4 to 15;

[0030] - MIL is from 0.1 to 400 g / 10 min, particularly from 0.5 to 150 g / 10 min or from 10 to 100 g / 10 min, where MIL is the melt flow index at 230 °C and 2.16 kg load as determined according to ISO 1133-2:2011;

[0031] - The amount of the fraction insoluble in xylene at 25°C is equal to or greater than 85% by weight, more preferably equal to or greater than 90% by weight, particularly in the case of propylene homopolymers, equal to or greater than 95% by weight, preferably 99% for all homopolymers and preferably 96% for all copolymers;

[0032] - Flexural modulus greater than 200 MPa, more preferably greater than 400 MPa, and in all cases preferably upper limit of 2000 MPa.

[0033] The propylene homopolymer and propylene copolymer are known in the art and are commercially available.

[0034] Examples of commercially available propylene homopolymers and copolymers are polymer products sold by LyondellBasell Industries under the trademark Moplen.

[0035] They can be prepared by using Ziegler-Natta catalysts or metallocene-based catalyst systems in the polymerization process.

[0036] Ziegler-Natta catalysts typically comprise reaction products (new symbols) of organometallic compounds from Groups 1, 2, or 13 of the periodic table with transition metal compounds from Groups 4 to 10 of the periodic table. In particular, the transition metal compounds can be selected from compounds of Ti, V, Zr, Cr, and Hf, and are preferably supported on MgCl2.

[0037] Particularly preferred catalysts comprise reaction products of organometallic compounds of Groups 1, 2, or 13 of the periodic table and solid catalyst components including Ti compounds supported on MgCl2 and electron donor compounds.

[0038] The preferred organometallic compounds are alkylaluminum compounds.

[0039] Therefore, preferred Ziegler-Natta catalysts are those that comprise reaction products containing the following substances:

[0040] 1) Solid catalyst components, comprising Ti compounds supported on MgCl2, preferably halogenated Ti compounds, particularly TiCl4, and electron donors (internal electron donors);

[0041] 2) Alkyl aluminum compounds (co-catalysts); and, optionally,

[0042] 3) Electron donor compounds (external electron donors).

[0043] The solid catalyst component (1) contains compounds typically selected from ethers, ketones, lactones, compounds containing N, P and / or S atoms, as well as monocarboxylic acid esters and dicarboxylic acid esters as electron donors.

[0044] Catalysts with the above-mentioned characteristics are known in patent literature; those described in U.S. Patent 4,399,054 and European Patent 45,977 are particularly advantageous.

[0045] Phthalate esters are particularly suitable among the internal electron donor compounds, with diisobutyl phthalate and succinate being preferred.

[0046] Other particularly suitable internal electron donors are 1,3-diethers, as described in published European patent applications EP-A-361493 and 728769.

[0047] As a cocatalyst (2), trialkylaluminum compounds, such as triethylaluminum, triisobutylaluminum and tri-n-butylaluminum, are preferred.

[0048] Electron-donating compounds (3) that can be used as external electron donors (added to alkylaluminum compounds) include aromatic esters (such as alkyl benzoates), heterocyclic compounds (such as 2,2,6,6-tetramethylpiperidine and 2,6-diisopropylpiperidine), and in particular silicon compounds containing at least one Si-OR bond (where R is a hydrocarbon radical).

[0049] Useful examples of silicon compounds are (tert-butyl)2Si(OCH3)2, (cyclohexyl)(methyl)Si(OCH3)2, (phenyl)2Si(OCH3)2 and (cyclopentyl)2Si(OCH3)2.

[0050] The previously described 1,3-diethers are also suitable as external electron donors. When the internal electron donor is one of the 1,3-diethers, the external electron donor can be omitted.

[0051] The catalyst can be pre-contaminated with a small amount of olefin (prepolymerization), the catalyst is kept in a suspension in a hydrocarbon solvent, and polymerized at a temperature from room temperature to 60°C, thereby producing a polymer in amounts from 0.5 to 3 times the weight of the catalyst.

[0052] This operation can also be carried out in liquid monomers, in which case up to 1000 times the weight of the catalyst is produced.

[0053] Preferred examples of metallocene-based catalyst systems are disclosed in US20060020096 and WO98040419.

[0054] The polymerization conditions used with the catalysts described above are also generally well known.

[0055] The polymerization can be carried out in a single step, or in two or more steps under different polymerization conditions.

[0056] It can occur in the liquid phase (e.g., using liquid propylene as a diluent), in the gas phase, or in a liquid-gas phase.

[0057] Conventional molecular weight modifiers known in the art, such as chain transfer agents (e.g., hydrogen or ZnEt2), can be used.

[0058] The polymerization temperature is preferably from 40 to 120°C; more preferably from 50 to 80°C.

[0059] The polymerization pressure can be atmospheric pressure or higher.

[0060] If polymerization is carried out in liquid propylene, the pressure is a pressure that competes with the vapor pressure of liquid propylene at the operating temperature used, and can be modified by the vapor pressure of a small amount of inert diluent used in the feed catalyst mixture, by the overpressure of optional monomers, and by hydrogen as a molecular weight regulator.

[0061] In particular, propylene polymer A) can be produced by a polymerization process carried out in a gas-phase polymerization reactor comprising at least two interconnected polymerization zones, as described in EP application 782587.

[0062] Specifically, the process is carried out in first and second interconnected polymerization zones. Propylene and optional comonomers are fed into the first and second interconnected polymerization zones in the presence of a catalyst system, and the resulting polymer is discharged from the first and second interconnected polymerization zones. In this process, the grown polymer particles flow upward under rapid fluidization conditions through one (first) of the polymerization zones (risers), exit the riser and enter the other (second) polymerization zone (downsink). They then flow downward under gravity in a densified form through the polymerization zone, exit the downsink and are reintroduced into the riser, thereby establishing a polymer cycle between the riser and the downsink.

[0063] In the downcomer, a high solids density is achieved, approaching the bulk density of the polymer. Therefore, a positive pressure gain can be obtained along the flow direction, allowing the polymer to be reintroduced into the riser without the aid of special mechanical devices. In this way, a "loop" circulation is established, defined by the pressure balance between the two polymerization zones and the head loss introduced into the system.

[0064] Typically, rapid fluidization conditions in the riser are established by feeding a gas mixture comprising the relevant monomers into the riser. Preferably, the gas mixture is fed below the point where the polymer is reintroduced into the riser, if appropriate, by using a gas distributor device. The rate at which the gas is introduced into the riser is higher than the conveying rate under operating conditions, preferably from 2 to 15 m / s.

[0065] Typically, the polymer and gas mixture exiting the riser is transported to a solid / gas separation zone. Solid / gas separation can be achieved using conventional separation equipment. The polymer enters the downcomer from the separation zone. The gaseous mixture exiting the separation zone is compressed, cooled, and transferred to the riser, with supplemental monomers and / or molecular weight modifiers added if appropriate. Transfer can be carried out via a gas mixture circulation line.

[0066] The control of polymer circulation between the two polymerization zones can be achieved by using devices suitable for controlling solid flow, such as mechanical valves, to meter the amount of polymer leaving the downcomer.

[0067] The process can be carried out at an operating pressure between 0.5 and 10 MPa, preferably between 1.5 and 6 MPa.

[0068] Optionally, one or more inert gases, such as nitrogen or aliphatic hydrocarbons, are maintained in the polymerization zone in such amounts that the sum of the partial pressures of the inert gases is preferably between 5% and 80% of the total gas pressure.

[0069] The catalyst can be fed upwards into the riser at any point. However, it can also be fed at any point in the downcomer. The catalyst can be in any physical state, so solid or liquid catalysts can be used.

[0070] A preferred example of a multiphase polyolefin composition A) is a composition comprising the following:

[0071] i) one or more propylene polymers selected from propylene homopolymers and propylene copolymers as previously defined, and mixtures thereof, and ii) a composition of copolymers or copolymers of ethylene with propylene and / or one or more CH2=CHRα-olefins, wherein R is a C2-C8 alkyl radical and optionally contains a small amount of diene (relative to ii), preferably from 1 to 10% by weight, said copolymer or composition containing 15% or more by weight, preferably from 15% to 90% by weight, particularly from 25% to 85% by weight of ethylene, relative to the weight of ii).

[0072] Particularly preferred examples of the multiphase polyolefin compositions are those containing 40 to 90% by weight of component i) and 10 to 60% by weight of component ii) relative to the total weight of i)+ii).

[0073] The CH2=CHRα-olefin that may be present in component ii) is the same as the aforementioned propylene copolymer.

[0074] A particularly preferred example is butene-1.

[0075] Preferred examples of dienes are butadiene, 1,4-hexadiene, 1,5-hexadiene and ethylidene-1-norbornene.

[0076] The multiphase polyolefin composition A) preferably has a MIL ranging from 0.1 to 50 g / 10 min, more preferably from 0.5 to 20 g / 10 min.

[0077] The elongation at break of the multiphase polyolefin composition is preferably from 100% to 1000%.

[0078] The flexural modulus of the multiphase polyolefin composition is preferably from 500 to 1500 MPa, more preferably from 700 to 1500 MPa.

[0079] Relative to the total weight of ii), the copolymer or copolymer composition ii) preferably has a solubility in xylene at 25°C from 40% to 100% by weight, more preferably from 50% to 100% by weight.

[0080] The multiphase polyolefin composition is known in the art and is commercially available.

[0081] Examples of commercially available multiphase polyolefin compositions are polymer products sold by LyondellBasell Industries under the trademark Moplen.

[0082] They can be prepared by blending components i) and ii) in the molten state, that is, at a temperature above their softening or melting point, or more preferably by sequential polymerization in the presence of the aforementioned Ziegler-Natta catalyst.

[0083] Other catalysts that can be used are metallocene catalysts, such as those described in USP 5,324,800 and EP-A-0129368; particularly advantageous are bridged bis-indenyl metallocenes, for example, those described in USP 5,145,819 and EP-A-0485823. These metallocene catalysts can be particularly used for the production of component ii).

[0084] The sequential polymerization process described above for producing multiphase polyolefin compositions includes at least two stages, wherein in one or more stages, propylene is optionally polymerized in the presence of the CH2=CHRα-olefin comonomer to form component i), and in one or more additional stages, ethylene is polymerized with propylene and / or a mixture of the CH2=CHRα-olefin comonomer and optionally diene to form component ii).

[0085] The polymerization process is carried out in a liquid, gas, or liquid / gas phase. The polymerization temperatures at each stage of polymerization can be the same or different, and the range for the production of component i) is typically from 40 to 90°C, preferably from 50 to 80°C, and for the production of component ii) from 40 to 60°C. Examples of sequential polymerization processes are described in European patent applications EP-A-472946 and EP-A-400333 and WO03 / 011962.

[0086] Butene-1 polymer B) is preferably a highly isotactic linear polymer, particularly having an isotactic regularity of 90 to 99%, more preferably 93 to 99%, and most preferably 95 to 99%, for use at 150.91 MHz. 13 C-NMR is measured as mmmm quintet / total quintet, or as the weight of a substance soluble in xylene at 0 °C.

[0087] Butene-1 polymer B) preferably has a MIE value from 1 to 3000 g / 10 min, more preferably from 50 to 3000 g / 10 min, wherein the MIE is the melt flow index at 190 °C and 2.16 kg load as determined according to ISO 1133-2:2011.

[0088] The highly preferred MIE value for butene-1 polymer B) is from 700 to 3000 g / 10 min.

[0089] In one embodiment, butene-1 polymer B) can be a copolymer having a comonomer content, particularly a copolymer of ethylene content ranging from 0.5 mol% to 5.0 mol%, preferably from 0.7 mol% to 3.5 mol%.

[0090] In a further embodiment, butene-1 polymer B) may be a butene-1 polymer composition comprising:

[0091] B1) Butene-1 homopolymer or butene-1 copolymer with at least one comonomer selected from ethylene, propylene, CH2=CHRα-olefins (previously defined) and mixtures thereof, wherein the comonomer content is at most 2 mol%.

[0092] B2) A copolymer of butene-1 and at least one comonomer selected from ethylene, propylene, the previously defined CH2=CHRα-olefin and mixtures thereof, wherein the comonomer content is from 3 to 5 mol%.

[0093] The composition has a total comonomer content of 0.5 to 4.0 mol%, preferably from 0.7 to 3.5 mol%, relative to the sum of B1) + B2).

[0094] The relative amounts of B1) and B2) can be in the range of 10 wt% to 40 wt%, particularly from 15 wt% to 35 wt%, and B2) from 90 wt% to 60 wt%, particularly from 85 wt% to 65 wt%, said amounts being relative to the sum of B1) and B2).

[0095] In one embodiment, butene-1 polymer B) may have at least one of the following additional features:

[0096] a) The molecular weight distribution (Mw / Mn) is equal to or less than 9, preferably equal to or less than 4, more preferably equal to or less than 3, most preferably equal to or less than 2.5, and in all cases the lower limit is preferably 1.5;

[0097] b) The melting point TmII measured by DSC (differential scanning calorimetry) during the second heating at a scanning rate of 10°C / min is equal to or lower than 125°C, preferably equal to or lower than 110°C, and in all cases the lower limit is preferably 80°C.

[0098] c) The Brinell viscosity at 190°C is from 1,500 to 20,000 mPa·sec, especially from 2,000 to 15,000 mPa·sec, or from 2,500 to 10,000 mPa·sec;

[0099] d) Using a device operating at 150.91MHz 13C-NMR could not detect the 4,1 insertion;

[0100] e) X-ray crystallinity ranges from 25% to 65%;

[0101] f) The glass transition temperature (Tg) is from -40°C to -10°C, preferably from -30°C to -10°C.

[0102] Optionally, the butene-1 polymer (B) may have at least one of the following further additional features:

[0103] i) The intrinsic viscosity (IV) of tetrahydronaphthalene (THN) measured at 135°C is equal to or less than 5 dl / g, preferably equal to or less than 2 dl / g, more preferably equal to or less than 0.6 dl / g, and in all cases the lower limit is preferably 0.2 dl / g;

[0104] ii) Mw equal to or greater than 30,000 g / mol, especially from 30,000 to 500,000 g / mol or from 30,000 to 100,000 g / mol;

[0105] iii) Melting point TmI from 95°C to 110°C, measured by DSC at a scan rate of 10°C / min;

[0106] iv) Density is 0.885 to 0.925 g / cm³ 3 Especially 0.890 to 0.920 g / cm³ 3 ;

[0107] The butene-1 polymer (B) can be obtained using known processes and polymerization catalysts.

[0108] As an example, to produce butene-1 polymer B), a Ziegler-Natta catalyst based on TiCl3 and aluminum derivatives, such as aluminum halides, can be used as co-catalysts, as well as the catalytic system supported on MgCl2 described above for the preparation of propylene polymer A).

[0109] When using the aforementioned supported catalytic system, additional examples of internal electron donor compounds are diethyl or diisobutyl 3,3-pentanoic acid dimethyl ester.

[0110] Preferred examples of external electron donor compounds are cyclohexyltrimethoxysilane, tert-butyltrimethoxysilane, diisopropyldimethoxysilane, and tert-hexyltrimethoxysilane. Tert-hexyltrimethoxysilane is particularly preferred.

[0111] Preferably, butene-1 polymer B) can be obtained by polymerizing monomers in the presence of a metallocene catalyst system, which can be obtained by contacting the following substances:

[0112] -Stereorigid metallocene compounds;

[0113] -Aluminoxanes or compounds capable of forming alkyl metallocene cations; and, optionally,

[0114] - Organoaluminum compounds.

[0115] Preferably, the stereolithic metallocene compound belongs to the following formula (I):

[0116]

[0117] in:

[0118] M is an atom selected from transition metals belonging to Group 4; preferably, M is zirconium;

[0119] X, which may be the same as or different from each other, is a hydrogen atom, a halogen atom, R, OR, OR'O, OSO2CF3, OCOR, SR, NR2, or PR2 group, wherein R is a straight-chain or branched, saturated or unsaturated C1-C group. 20 -alkyl, C3-C 20 -Cycloalkyl, C6-C 20 -Aryl, C7-C 20 -alkylaryl or C7-C 20 -Arylalkyl radical, optionally containing a heteroatom belonging to Groups 13 to 17 of the periodic table; and R' is C1-C 20 -alkylene, C6-C 20 -Asaryl, C7-C 20 -alkylarylene or C7-C 20 -Arylalkylene radical; preferably, X is a hydrogen atom, a halogen atom, an OR'O or an R group; more preferably, X is a chlorine or methyl radical;

[0120] R that are the same or different from each other 1 R 2 R 5 R 6 R 7 R 8 and R 9 It is a hydrogen atom, or a straight-chain or branched, saturated or unsaturated C1-C atom. 20 -alkyl, C3-C 20 -Cycloalkyl, C6-C 20 -Aryl, C7-C 20 -alkylaryl or C7-C 20 -Arylalkyl radical, optionally containing heteroatoms belonging to groups 13 to 17 of the periodic table; or R 5 and R 6 , and / or R 8 and R9 Saturated or unsaturated 5- or 6-membered rings can be optionally formed, and the rings may have C1-C2 groups. 20 Alkyl radicals are used as substituents; the condition is R. 6 Or R 7 At least one of them is a straight-chain or branched, saturated or unsaturated C1-C 20 -alkyl radical, optionally containing heteroatoms belonging to groups 13 to 17 of the periodic table; preferably C1-C 10 -alkyl radical;

[0121] R that are the same or different from each other 3 and R 4 It is a straight-chain or branched, saturated or unsaturated C1-C 20 -alkyl radicals, optionally containing heteroatoms belonging to groups 13 to 17 of the periodic table; preferably, R atoms that are the same or different from each other. 3 and R 4 It is C1-C 10 -alkyl radical; more preferably, R 3 It is a methyl or ethyl radical; and R 4 It is a methyl, ethyl, or isopropyl free radical.

[0122] Preferably, the compound of formula (I) has formula (Ia):

[0123]

[0124] in:

[0125] M, X, R 1 R 2 R 5 R 6 R 8 and R 9 As described above;

[0126] R 3 It is a straight-chain or branched, saturated or unsaturated C1-C 20 -alkyl radical, optionally containing heteroatoms belonging to groups 13 to 17 of the periodic table; preferably, R 3 It is C1-C 10 -alkyl radical; more preferably, R 3 It is a methyl or ethyl free radical.

[0127] Specific examples of metallocene compounds are dimethylsilyl{(2,4,7-trimethyl-1-indyl)-7-(2,5-dimethyl-cyclopentadieno[1,2-b:4,3-b']-dithiophene)}zirconium dichloride; dimethylsilyl{(1-(2,4,7-trimethylindyl)-7-(2,5-dimethyl-cyclopentadieno[1,2-b:4,3-b']-dithiophene)}zirconium dichloride and dimethylsilyl{(1-(2,4,7-trimethylindyl)-7-(2,5-dimethyl-cyclopentadieno[1,2-b:4,3-b']-dithiophene)}dimethylzirconium.

[0128] Examples of aluminum oxanes are methylaluminoxane (MAO), tetra-(isobutyl)aluminoxane (TIBAO), tetra-(2,4,4-trimethyl-pentyl)aluminoxane (TIOAO), tetra-(2,3-dimethylbutyl)aluminoxane (TDMBAO) and tetra-(2,3,3-trimethylbutyl)aluminoxane (TTMBAO).

[0129] An example of a compound capable of forming an alkyl metallocene cation is formula D. + E - Compound, in which D + It is Brønsted acid ( acid), which can donate a proton and react irreversibly with the metallocene substituent X of formula (I), and E - It is a compatible anion that can stabilize the active catalyst derived from the reaction of the two compounds, and is sufficiently unstable to be removed by the olefin monomer. Preferably, the anion E - It includes one or more boron atoms.

[0130] Examples of organoaluminum compounds are trimethylaluminum (TMA), triisobutylaluminum (TIBA), tri(2,4,4-trimethyl-pentyl)aluminum (TIOA), tri(2,3-dimethylbutyl)aluminum (TDMBA), and tri(2,3,3-trimethylbutyl)aluminum (TTMBA).

[0131] Examples of the catalyst system and polymerization processes using such catalyst systems can be found in WO2004099269 and WO2009000637.

[0132] The polymerization process with the catalyst can be carried out in the liquid phase, optionally in the presence of an inert hydrocarbon solvent, or in the gas phase, using a fluidized bed or mechanically stirred gas-phase reactor.

[0133] The hydrocarbon solvent can be aromatic (such as toluene) or aliphatic (such as propane, hexane, heptane, isobutane, cyclohexane, and 2,2,4-trimethylpentane, isododecane).

[0134] Preferably, the polymerization process is carried out using liquid butene-1 as the polymerization medium.

[0135] The polymerization temperature can range from 20°C to 150°C, especially from 50°C to 90°C, for example from 65°C to 82°C.

[0136] To control molecular weight, molecular weight regulators, especially hydrogen, are fed into the polymerization environment.

[0137] It can also be operated according to a multi-step polymerization process, in which butene-1 polymers with different compositions and / or molecular weights are prepared sequentially in two or more reactors with different reaction conditions, such as the concentration of molecular weight regulators and / or comonomers fed into each reactor.

[0138] In particular, when the butene-1 polymer of the present invention comprises the two previously described components B1) and B2), the polymerization process can be carried out in two or more reactors connected in series, wherein components B1) and B2) are prepared in separate subsequent stages, and in each stage except the first stage, the process is carried out in the presence of the polymer formed and the catalyst used in the previous stage.

[0139] The catalyst may be added only in the first reactor or in more than one reactor.

[0140] For all the aforementioned polymer components, high melt index values ​​can be obtained directly during polymerization or through subsequent chemical treatment (chemical de-viscosity cracking).

[0141] The chemical de-tackification cracking of polymers is carried out in the presence of free radical initiators such as peroxides.

[0142] The peroxides most conveniently used in polymer viscosity-reducing cracking processes have a decomposition temperature preferably ranging from 150°C to 250°C. Examples of such peroxides are di-tert-butyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne, and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, all of which are commercially available.

[0143] The amount of peroxide required for the viscosity-reducing cracking process is preferably in the range of 0.001 to 0.5% by weight of the polymer, more preferably from 0.001 to 0.2%.

[0144] The term "clarifying agent" is intended to refer to any additive that causes a reduction in haze when added to a propylene polymer or a multiphase composition comprising said propylene polymer.

[0145] Preferably, the clarifying agent has the effect of reducing the haze value of the polymer by at least 20%, more preferably at least 30%, and particularly at least 50%.

[0146] The reduction is preferably achieved when a clarifying agent is added to the propylene polymer in an amount ranging from 0.025% to 0.2% by weight relative to the total weight of the propylene polymer and the clarifying agent.

[0147] As mentioned earlier, clarifying agents usually belong to the nucleating agent category.

[0148] Suitable clarifying agents include polyols, preferably derivatives of sorbitol, xylitol and nonanol, especially acetals, phosphates and carboxylates.

[0149] Specific examples of acetals of sorbitol and xylitol include dibenzyl sorbitol; di(alkylbenzyl)sorbitol, particularly di(p-methylbenzyl)sorbitol, di(o-methylbenzyl)sorbitol and di(p-ethylbenzyl)sorbitol; bis(3,4-dialkylbenzyl)sorbitol, particularly 1,3; 2,4-bis(3,4-dimethylbenzyl)sorbitol and bis(3,4-diethylbenzyl)sorbitol; bis(5',6',7',8'-tetrahydro-2-naphthyl)sorbitol; bis(trimethylbenzyl)xylitol and bis(trimethylbenzyl)sorbitol.

[0150] The sorbitol and xylitol acetal, and their use as clarifying agents, are disclosed in U.S. Patent 5,310,950.

[0151] Examples of commercial products include 3988, 1,3;2,4-bis(3,4-dimethylbenzyl)sorbitol in powder form; NXTM8000, 1,2,3-trideoxy-4,6:5,7-bis-O-[(4-propylphenyl)methylene]-nonanol and NXTM8500E, another nonanol-based clarifying agent.

[0152] Examples of commercially available phosphate salts used as clarifying agents include stabilizers NA-11, sodium 2,2'-methylene-bis-(4,6-di-tert-butylphenyl)phosphate, NA-21, hydroxybis[2,2'-methylene-bis-(4,6-di-tert-butylphenyl)phosphate], and NA-71, all purchased from Adeka.

[0153] Examples of carboxylates are dicarboxylates, particularly bicyclic [2.2.1]heptane dicarboxylates, such as those based on disodium n-norbornene-2,3-dicarboxylate. HPN-68L, and cyclohexane dicarboxylate, such as calcium cyclohexane-1,2-dicarboxylate. HPN-20E.

[0154] Particularly preferred clarifying agents are di(alkylbenzyl)sorbitol, bis(3,4-dialkylbenzyl)sorbitol, especially 1,3-O-2,4-bis(3,4-dimethylbenzyl)sorbitol, and nonanol derivatives, especially 1,2,3-trideoxy-4,6:5,7-bis-O-[(4-propylphenyl)methylene]-nonanol.

[0155] The preferred amount of clarifying agent C) relative to the total weight of A)+B)+C) is from 0.02 wt% to 0.3 wt%, particularly from 0.05 wt% to 0.25 wt%, or from 0.05 wt% to 0.2 wt%, or from 0.1 wt% to 0.2 wt%.

[0156] Therefore, in a preferred embodiment, the polyolefin composition of the present invention comprises:

[0157] A) From 97.7% by weight to 99.97% by weight, preferably from 98.25% by weight to 99.935% by weight, more preferably from 99.3% by weight to 99.93% by weight, and most preferably from 99.5% by weight to 99.88% by weight of a propylene polymer or a multiphase polyolefin composition comprising said propylene polymer and an ethylene copolymer;

[0158] B) From 0.01 wt% to 2 wt%, preferably from 0.015 wt% to 1.5 wt%, more preferably from 0.02 wt% to 0.5 wt%, most preferably from 0.02 wt% to 0.3 wt%, particularly from 0.02 wt% to 0.2 wt% of butene-1 polymer; and

[0159] C) A clarifying agent in the range of 0.02% to 0.3% by weight, preferably from 0.05% to 0.25% by weight, more preferably from 0.05% to 0.2% by weight, and most preferably from 0.1% to 0.2% by weight;

[0160] The quantities of A), B), and C) are relative to the total weight of A) + B) + C).

[0161] Preferably, the weight ratio of C) / B) is from 0.5 to 4, more preferably from 1 to 3.5.

[0162] The polyolefin compositions of the present invention may also contain additives, fillers and pigments commonly used in olefin polymers, such as stabilizers (heat, light, UV resistant), plasticizers, acid resistant agents, antistatic agents and waterproofing agents, and organic and inorganic pigments.

[0163] Preferably, the polyolefin composition of the present invention has at least one of the following characteristics:

[0164] -The haze value measured on a 1 mm plate according to ASTM D 1003-13 is equal to or less than 20%, more preferably equal to or less than 15%, and in both cases the lower limit is preferably 2%;

[0165] - MIL ranges from 0.1 to 400 g / 10 minutes, especially from 0.5 to 150 g / 10 minutes, or from 10 to 100 g / 10 minutes;

[0166] - According to ISO 527-1:2019, the elongation at break, measured 10 days after molding on a pressure plate, ranges from 500 to 1500%.

[0167] - The Charpy notch, measured at 23°C according to ISO 179 / 1eA:2010 48 hours after molding, ranges from 2 to 10 kJ / m. 2 ;

[0168] - The Charpy notch, measured at 0°C according to ISO 179 / 1eA:2010 48 hours after molding, ranges from 1 to 5 kJ / m. 2 ;

[0169] - Melting temperature is from 142 to 153°C;

[0170] - The crystallization temperature is from 114 to 120°C.

[0171] The polyolefin compositions of the present invention can be prepared by blending components at a temperature typically from 180 to 310°C, preferably from 190 to 280°C, and more preferably from 200 to 250°C. Any known equipment and techniques can be used for this purpose.

[0172] In this context, useful melt blending equipment includes extruders or kneaders, with twin-screw extruders being particularly preferred. The components can also be premixed in a mixing apparatus at room temperature.

[0173] Alternatively, the premixed component form of the polyolefin composition of the present invention can be directly fed into the processing equipment for preparing the final product, thereby omitting the previous melt blending step.

[0174] The polyolefin compositions of the present invention can be processed in conventional polymer processing machines.

[0175] In particular, the polyolefin compositions of the present invention are especially suitable for the preparation of injection molded articles, including injection blow molded and injection stretch blow molded articles, such as conventional molded articles (e.g., household utensils), bottles and containers.

[0176] Therefore, this disclosure also provides injection-molded articles comprising the polyolefin composition. Such injection-molded articles are preferably characterized by a wall thickness equal to or greater than 0.1 mm, more preferably equal to or greater than 0.5 mm.

[0177] Injection molded articles are typically manufactured using processes and equipment known in the art. Generally, the injection molding process includes a step of melting the polymer and a subsequent step of injecting the molten polymer into a mold under pressure. Injection-molded tubular structures can also be produced by blowing air into them while they soften at a suitable temperature, thereby forcing the softened tube to conform to the inner wall of the mold.

[0178] Temperature and pressure are those typically used in injection molding processes. In particular, it can be operated at melt temperatures ranging from 180 to 230°C and injection pressures ranging from 1 to 150 MPa.

[0179] Example

[0180] The various embodiments, compositions, and methods provided herein are disclosed in the following examples. These examples are merely illustrative and are not intended to limit the scope of the invention.

[0181] The following analytical methods are used to characterize polymer compositions.

[0182] MIE and MIP

[0183] Determined according to standard ISO 1133-2:2011 at specified temperature and load.

[0184] Comonomer content

[0185] Propylene polymer A)

[0186] For propylene copolymers, the comonomer content was determined by infrared spectroscopy using a Fourier transform infrared spectrometer (FTIR) to collect the IR spectrum of the sample against the air background. The instrument data acquisition parameters were:

[0187] -Purge time: minimum 30 seconds;

[0188] - Collection time: Minimum 3 minutes;

[0189] - Happ-Genzel;

[0190] - Resolution: 2cm -1 .

[0191] Sample preparation

[0192] Using a hydraulic press, a thick sheet is obtained by pressing a sample of approximately g 1 between two aluminum foils. If uniformity issues exist, it is recommended to perform at least two pressing operations. A small portion is then cut from this sheet to mold a film. The recommended film thickness range is between 0.02 and 0.05 cm (8 to 20 mils).

[0193] The pressing temperature is 180±10℃ (356℉) and the pressing volume is approximately 10 kg / cm³. 2 A pressure of (142.2 PSI) was applied for approximately 1 minute. The pressure was then released, and the sample was removed from the press and cooled to room temperature.

[0194] Absorbance versus wavenumber (cm) -1 Record the spectrum of the polymer-pressed film. Use the following measurements to calculate the ethylene and butene-1 content:

[0195] - at 4482 and 3950cm –1 The area (At) of the combined absorption bands between the two is used for spectral normalization of the film thickness.

[0196] - If ethylene is present, the area of ​​the absorption band (AC2) after two appropriate successive spectral subtractions of the spectrum of isotactic unadulterated polypropylene is between 750 and 700 cm⁻¹. -1 Between, and then if butene-1 is present, the area (AC2) of the reference spectrum of the butene-1-propylene random copolymer ranges from 800 to 690 cm⁻¹. -1 .

[0197] - If butene-1 is present, the absorption band height (DC4) is 769 cm⁻¹ after two appropriate successive spectral subtractions of the isotactic unadulterated polypropylene spectrum. -1 (Maximum), and then if ethylene is present, the height (DC4) of the reference spectrum for the ethylene-propylene random copolymer ranges from 800 to 690 cm⁻¹. -1 .

[0198] To calculate the ethylene and butene-1 content, a calibration line for ethylene and butene-1 is required, obtained by using samples with known amounts of ethylene and butene-1.

[0199] Butene-1 polymer B)

[0200] The comonomer content was determined by FT-IR.

[0201] Absorbance versus wavenumber (cm) -1 Record the spectrum of the polymer-pressed film. Use the following measurements to calculate the ethylene content:

[0202] a) at 4482 and 3950cm -1 The area of ​​the combined absorption band between (A) t ), which is used for spectral normalization of film thickness.

[0203] b) The subtraction factor (FCR) of the numerical subtraction between the polymer sample's spectrum and the absorption bands of the sequences BEE and BEB (B: 1, butene unit, E: ethylene unit) due to the methylene group (CH2 rocking vibration). C2 ).

[0204] c) Subtract the area of ​​the residual band after the C2PB spectrum (A) C2，块 It originates from the sequence EEE (CH2 rocking vibration) of the methylene group.

[0205] equipment

[0206] The spectral measurements reported above can be provided using a Fourier transform infrared spectrometer (FTIR).

[0207] Use a hydraulic press (Carver or equivalent) with a plate that can be heated up to 200°C.

[0208] method

[0209] Calibration of (BEB+BEE) sequence

[0210] By plotting (BEB+BEE) weight % against FCR C2 / A t To obtain the calibration line. Slope G r and intercept I r Calculated by linear regression.

[0211] EEE sequence calibration

[0212] By plotting (EEE) weight % against A C2，块 / A t To obtain the calibration line. Slope G H and intercept I H Calculated by linear regression.

[0213] Sample preparation

[0214] Using a hydraulic press, a thick sheet is obtained by pressing a sample of approximately 1.5g between two aluminum foils. If uniformity issues exist, it is recommended to perform at least two pressing operations. A small portion is then cut from this sheet to form a molded film. The recommended film thickness is between 0.1 and 0.3mm.

[0215] The pressing temperature is 140±10℃.

[0216] Crystalline phase modification occurs over time, so it is recommended to collect the IR spectrum of the sample film as soon as it is formed.

[0217] program

[0218] The instrument data acquisition parameters are as follows:

[0219] Purging time: minimum 30 seconds.

[0220] Collection time: minimum 3 minutes.

[0221] Happ-Genzel.

[0222] Resolution: 2cm -1 .

[0223] Collect the IR spectrum of the sample against the air background.

[0224] calculate

[0225] Calculate the weight concentration of the BEE+BEB sequence in the ethylene unit:

[0226]

[0227] The residual area (AC2, block) after the above subtraction is calculated using the baseline between the shoulders of the residual band.

[0228] Calculate the weight concentration of the EEE sequence of the ethylene unit:

[0229]

[0230] Calculate the total weight percentage of ethylene:

[0231] %C2wt=[%(BEE+BEB)wt+%(EEE)wt]

[0232] Haze

[0233] Measurements were taken on a 1 mm plate according to ASTM D 1003-13. A 7.5 x 7.5 cm specimen was cut from a 1 mm thick molded plate, and the haze value was measured using a Gardner photometric unit connected to a UX-10 haze meter or an equivalent instrument with a GE1209 light source with filter "C". A reference sample with known haze was used to calibrate the instrument.

[0234] The board to be tested is produced according to the following method.

[0235] Using a GBFPlastiniector G235 / 90 injection molding machine (90 tons), mold a 75x75x1 mm sheet under the following processing conditions:

[0236] Screw speed: 120 rpm;

[0237] Back pressure: 10 bar;

[0238] Melting temperature: 230℃;

[0239] Injection time: 5 seconds;

[0240] Switch holding pressure: 50 bar;

[0241] Phase 1: Maintain pressure at 43 bar;

[0242] Second-stage pressure: 20 bar;

[0243] Maintain pressure profile: Phase 1, 5 seconds;

[0244] The second phase lasts 10 seconds;

[0245] Cooldown: 20 seconds;

[0246] Mold water temperature: 40℃.

[0247] luster

[0248] The specular gloss properties were measured at a 60° angle using a micro TRI gloss meter manufactured by BYK-Gardner, conforming to ASTM D 523-14 (2018), with a black felt backing. The gloss meter was calibrated using black glass.

[0249] Tensile modulus

[0250] Measured according to ISO 527-2:2012.

[0251] Charpy impact strength

[0252] Measurements were taken at 23°C and 0°C 48 hours after molding, according to ISO 179 / 1eA:2010.

[0253] Tensile stress, yield elongation, and elongation at break

[0254] According to standard ISO 527-1:2019, measurements were taken on a pressing plate 10 days after molding.

[0255] Flexural modulus

[0256] Measurements were taken 48 hours after molding, according to standard ISO 178:2019.

[0257] Brinell viscosity

[0258] Measurements were taken at 190°C using the HA Ametek / Benelux Scientific Model DV2T rotary viscometer with a cylindrical mandrel, which is equipped with a drive motor capable of variable test speed and a set of mandrels capable of achieving and maintaining approximately 80% of the torque.

[0259] The selected axis / chamber combination is SC4-27 / SC4-13R / RP.

[0260] During the test, the sample was subjected to a gradual increase in rotation until approximately 80% of the torque value was reached and maintained. The rotation was started at 10 RPM, then gradually increased by 2 RPM every 5 seconds.

[0261] The Brinell viscosity, expressed in mPa*s, is calculated as the ratio of shear stress (mPa) to shear rate (sec⁻¹) and determined by the results obtained during the last 20 minutes of acquisition (1 data point / minute).

[0262] Intrinsic viscosity (IV)

[0263] Determined at 135°C according to the standard ASTM D 2857-16 for tetrahydronaphthalene.

[0264] Multidispersion Index (PI)

[0265] Measurements were taken at 200°C using an RMS-800 parallel plate rheometer sold by RHEOMETRICS (USA), operating at oscillation frequencies increasing from 0.1 rad / s to 100 rad / s. Based on the cross modulus, PI can be derived using the following formula:

[0266] PI=10 5 / Gc

[0267] Where Gc is the cross modulus, which is defined as the value (in Pa) when G' = G”, where G' is the storage modulus and G” is the loss modulus.

[0268] Fractions soluble and insoluble in xylene at 25°C (XS-25°C)

[0269] 2.5 g of polymer was dissolved in 250 ml of xylene at 135 °C with stirring. After 20 minutes, the solution was cooled to 25 °C while still stirring, and then allowed to settle for 30 minutes. The precipitate was filtered through filter paper, the solution was evaporated in a nitrogen stream, and the residue was vacuum dried at 80 °C until constant weight was achieved. Therefore, the weight percentages of polymer solubles (xylene solubles - XS) and insolubles at room temperature (25 °C) were calculated.

[0270] The weight percentage of a polymer that is insoluble in xylene at room temperature (25°C) is considered the isotactic index of the polymer. This value essentially corresponds to the isotactic index determined by extraction with boiling n-heptane, which by definition constitutes the isotactic index of propylene polymers.

[0271] Fractions soluble and insoluble in xylene at 0°C (XS-0°C)

[0272] 2.5 g of polymer sample was dissolved in 250 ml of xylene at 135 °C with stirring. After 30 minutes, the solution was cooled to 100 °C while still stirring, and then placed in a water and ice bath to cool to 0 °C. The solution was then allowed to settle in a water and ice bath for 1 hour. The precipitate was filtered through filter paper. During filtration, the flask was placed in a water and ice bath to keep the internal temperature of the flask as close to 0 °C as possible. Once filtration was complete, the filtrate temperature was equilibrated to 25 °C, the volumetric flask was immersed in a water flow bath for about 30 minutes, and then divided into two 50 ml aliquots. The aliquots were evaporated in a nitrogen stream, and the residues were vacuum dried at 80 °C until constant weight was achieved. The weight difference between the two residues must be less than 3%; otherwise, the test must be repeated. Therefore, the weight percentage of polymer-soluble matter was calculated from the average weight of the residues (xylene-soluble matter at 0 °C = XS / 0 °C). The insoluble fraction in o-xylene at 0°C (xylene insolubles at 0°C = XI% at 0°C) is:

[0273] XI%0℃=100-XS%0℃.

[0274] Melting and crystallization temperatures of butene-1 polymer B by differential scanning calorimetry (DSC)

[0275] Differential scanning calorimetry (DSC) data were obtained using a Perkin Elmer DSC-7 instrument with weighted samples (5 to 10 mg) sealed in an aluminum disk.

[0276] To determine the melting temperature (TmI) of polybutene-1 crystal form I, the sample was heated to 200°C at a scan rate corresponding to 10°C / min, held at 200°C for 5 minutes, and then cooled to 20°C at a cooling rate of 10°C / min. The sample was then stored at room temperature for 10 days. After 10 days, the sample was subjected to DSC, cooled to -20°C, and then heated to 200°C at a scan rate corresponding to 10°C / min. During this heating run, the highest temperature peak in the thermogram was taken as the melting temperature (TmI).

[0277] To determine the melting temperature (TmII) and crystallization temperature T of polybutene-1 crystal form II. c The sample was heated to 200°C at a scan rate corresponding to 10°C / min and held at 200°C for 5 minutes to allow all microcrystals to completely melt, thereby eliminating the thermal history of the sample. Then, it was cooled to -20°C at a scan rate corresponding to 10°C / min, and the peak temperature was considered as the crystallization temperature (Tc). cThe area was considered as the enthalpy of crystallization. After standing at -20°C for 5 minutes, the sample was heated a second time to 200°C at a scan rate corresponding to 10°C / min. In this second heating run, the peak temperature was considered as the melting temperature (TmII) of polybutene-1 crystal form II, and the area was considered as the enthalpy of melting (ΔHfII).

[0278] NMR analysis of chain structure

[0279] 13 C10 NMR spectra were acquired on a Bruker AV-600 spectrometer equipped with a cryoprobe, which was operated at 150.91 MHz in Fourier transform mode at 120 °C.

[0280] T βδ Carbon peaks (according to the nomenclature of C.J. Carman, R.A. Harrington, and C.E. Wilkes, *Macromolecules*, 10, 3 ,536(1977)) was used as an internal reference at 37.24 ppm. The sample was dissolved in 1,1,2,2-tetrachloroethane-d2 at a concentration of 8 wt% at 120 °C. 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. Approximately 512 transients were stored in 32K data points using a 9000Hz spectral window.

[0281] According to Kakugo [M. Kakugo, Y. Naito, K. Mizunuma and T. Miyatake, Macromolecules, 16, 4, 1160 (1982)] and Randall [J. C. Randall, Macromolecular Chemistry and Physics, C30, 211 (1989)], the following were used to assign values ​​to the spectra, evaluate the ternary distribution and composition:

[0282] BBB = 100(T) ββ ) / S=I5

[0283] BBE = 100T β δ / S=I4

[0284] EBE = 100P δδ / S=I14

[0285] BEB = 100S ββ / S=I13

[0286] BEE = 100S αδ / S=I7

[0287] EEE = 100(0.25S) γδ +0.5S δδ ) / S=0.25I9+0.5I10

[0288]

[0289]

[0290] For the first approximation, mmmm is calculated using 2B2 carbon as follows:

[0291] area Chemical shift Assignment B1 28.2-27.45 mmmm B2 27.45–26.30

[0292] mmmm=B1*100 / (B1+B2-2*A4-A7-A 14 )

[0293] Molecular weight determined by GPC

[0294] In 1,2,4-trichlorobenzene (TCB), measurements were performed by gel permeation chromatography (GPC). Molecular weight parameters (Mn, Mw) and molecular weight distributions (Mw / Mn) for all samples were measured using a PolymerChar GPC-IR instrument equipped with four PLgel Olexis mixed-bed columns (PolymerLab) and an IR5 infrared detector (PolymerChar). The column size was 300 × 7.5 mm with a particle size of 13 μm. The mobile phase flow rate was maintained at 1.0 mL / min. All measurements were performed at 150 °C. The solution concentration was 2.0 mg / mL (at 150 °C) with 0.3 g / L of 2,6-di-tert-butyl-p-cresol added to prevent degradation. For GPC calculations, universal calibration curves were obtained using 12 polystyrene (PS) standards supplied by PolymerChar (peak molecular weight range from 266 to 1,220,000). Third-order polynomial fitting was used to interpolate the experimental data and obtain relevant calibration curves. Data acquisition and processing were performed using Empower 3 (Waters). Molecular weight distribution and associated average molecular weight were determined using the Mark-Houwink relationship: the K values ​​for PS and polybutene (PB) were K0 and K1, respectively. PS =1.21×10 -4 dL / g and K PB =1.78×10 -4 dL / g, with the Mark-Howwink index α = 0.706 for PS and α = 0.725 for PB.

[0295] For butene / ethylene copolymers, for data evaluation purposes, it is assumed that the composition of each sample is constant across the entire molecular weight range, and the K-value of the Mark-Howwink relationship is calculated using the linear combination reported below:

[0296] K EB =x E K PE +x B K PB

[0297] Where K EB K is the constant of the copolymer. PE (4.06×10 -4 (dL / g) and K PB (1.78×10 -4 dL / g) is a constant for polyethylene (PE) and PB, x E and x B It is the relative weight of ethylene and butene, where x E +x B =1. The Mark-Howwink index α = 0.725 was used independently for the composition of all butene / ethylene copolymers. Final processing data for all samples were fixed to include fractions above 1000 in terms of molecular weight equivalents. Fractions below 1000 were studied by GC.

[0298] Determination of X-ray crystallinity

[0299] X-ray crystallinity was measured using an X-ray powder diffractometer (XDPD) that uses Cu-Kα1 radiation with a fixed slit and is able to collect spectra between diffraction angles 2Θ = 5° and 2Θ = 35° in steps of 0.1° every 6 seconds.

[0300] The samples were disks with a thickness of approximately 1.5 to 2.5 mm and a diameter of 2.5 to 4.0 cm, prepared by compression molding. The disks were aged at room temperature (23°C) for 96 hours.

[0301] After this preparation, the sample is inserted into the XDPD sample support. The XRPD instrument is adjusted to collect the XRPD spectrum of the sample from the diffraction angle 2Θ = 5° to 2Θ = 35° using a counting time of 6 seconds in steps of 0.1°, and the final spectrum is collected at the end.

[0302] Ta is defined as the total area between the spectral profile and the baseline, expressed in counts / sec·2Θ, and Aa is defined as the total amorphous area, expressed in counts / sec·2Θ, while Ca is the total crystalline area, expressed in counts / sec·2Θ.

[0303] Analyze the spectrum or diffraction pattern in the following steps:

[0304] 1) Define a suitable linear baseline for the entire spectrum and calculate the total area (Ta) between the spectral profile and the baseline;

[0305] 2) Define a suitable amorphous profile along the entire spectrum, which separates the amorphous region from the crystalline region according to the two-phase model;

[0306] 3) Calculate the amorphous area (Aa) as the area between the amorphous profile and the baseline;

[0307] 4) Calculate the crystallization area (Ca) that serves as the area between the spectral profile and the amorphous profile, such as Ca = Ta - Aa

[0308] 5) Calculate the crystallinity (%Cr) of the sample using the following formula:

[0309] %Cr = 100x Ca / Ta

[0310] density

[0311] Measured at 23°C according to ISO 1183-1:2012.

[0312] Glass transition temperature via DMTA (Dynamic Mechanical Thermal Analysis) A 76mm × 13mm × 1mm molded specimen was fixed on a DMTA machine for tensile stress. The tension and dependence frequency of the specimen were fixed at 1Hz. DMTA converted the elastic response of the specimen from -100℃ to 130℃. In this way, a graph of the elastic response versus temperature can be plotted. The elastic modulus of viscoelastic materials is defined as E = E' + iE". DMTA can separate the two components E' and E" from their resonance and graphs E' versus temperature and E' / E" = tan(δ) versus temperature.

[0313] The glass transition temperature Tg is assumed to be the temperature at the maximum value of the curve E' / E”=tan(δ) with respect to temperature.

[0314] Melting temperature and crystallization temperature of polyolefin compositions

[0315] Samples weighing between 5 and 7 mg were measured using a DSC instrument conforming to ISO 11357-3:2018, under both cooling and heating conditions, at a scan rate of 20 °C / min in an inert N2 flow. The instrument was calibrated using indium.

[0316] Material

[0317] The materials described below are used in the following examples.

[0318] Propylene polymer A)

[0319] A copolymer of propylene and 3% by weight of ethylene has the following properties:

[0320] -MIL is 75g / 10 minutes;

[0321] - Haze level was 56.4%;

[0322] - Gloss level is 97.1;

[0323] - The fraction insoluble in xylene at 25°C is 94% by weight;

[0324] - The flexural modulus is approximately 1000 MPa.

[0325] Butene-1 polymer B)

[0326] Two different polymers were used, namely butene-1 polymer B)-I and butene-1 polymer B)-II.

[0327] Butene-1 polymer B)-I

[0328] The preparation is as reported below.

[0329] Preparation of catalytic solution

[0330] Under a nitrogen atmosphere, 6400 g of a 33 g / L solution of triisobutylaluminum (TIBA) in isododecane and 567 g of a 30 wt% solution of methylaluminoxane (MAO) in toluene were loaded into a 20 L jacketed glass reactor, stirred with an anchor stirrer, and allowed to react at room temperature for about 1 hour with stirring.

[0331] Subsequently, 1.27 g of metallocene dimethylsilyl{(2,4,7-trimethyl-l-indenyl)-7-(2,5-dimethyl-cyclopentadieno[l,2-b:4,3-b']-dithiophene)}zirconium dichloride prepared according to Example 32 of WO0147939 was added and dissolved under stirring for about 30 minutes.

[0332] The final solution is discharged from the reactor into a cylinder through a filter to remove the final solid residue.

[0333] The composition of the resulting solution is as follows:

[0334] Al (wt%) Zr (by weight) Al / Zr (molar ratio) Metallocene concentration (mg / L) 1.72 0.0029 2001 137

[0335] polymerization

[0336] Polymerization was carried out in two stirred reactors operating in series, with liquid butene-1 forming the liquid medium. The catalyst solution described above was fed into both reactors. Polymerization conditions are reported in Table 1. The butene-1 / ethylene copolymer was recovered from the solution as a melt and granulated. The copolymer was further characterized, and the data are recorded in Table 2.

[0337] Table 1

[0338]

[0339]

[0340] Note: C 2- = Ethylene; kg / gMe = kilograms of polymer per gram of metallocene; Split = amount of polymer produced in the relevant reactor.

[0341] Table 2

[0342] MIE (190℃ / 2.16Kg) g / 10 minutes 1200 Intrinsic viscosity (IV) dl / g 0.4 Mw / Mn 2.1 TmII ℃ 81.9 TmI ℃ 103 Tg ℃ -13 Brinell viscosity (180℃) mPa.s 6900 Crystallinity (X-ray) ％ 58 density <![CDATA[g / cm 3 ]]> 0.9090 Flexural modulus MPa 350

[0343] Butene-1 polymer B)-II

[0344] Polymerization was carried out in two stirred reactors operating in series, using the same catalytic solution and polymerization equipment as used for the preparation of butene-1 polymer B)-I, with liquid butene-1 constituting the liquid medium. The catalyst solution was injected into both reactors, and polymerization was carried out continuously at a polymerization temperature of 75°C. The residence time in each reactor was in the range of 120 ÷ 200 minutes. The hydrogen concentration during polymerization was 4900 ppmmol H2 / (C) 4- ) ontology, where C 4- =Butene-1. Comonomers in C 2- / C 4- 0.35% by weight of the feed is introduced into the reactor. The ethylene comonomers copolymerize almost immediately (C... 2- (Stoichiometric feed into the reactor). Catalyst yield (mileage) was 2000 kg / g of metallocene active component. The butene-1 copolymer was recovered from the solution as a melt and granulated. The copolymer was further characterized, and the data are recorded in Table 3.

[0345] Table 3

[0346]

[0347]

[0348] Clarifying agent C)

[0349] 1,3;2,4-bis(3,4-dimethylbenzyl)sorbitol, marketed by Milliken under the trademark Millad3988.

[0350] Preparation of polyolefin compositions

[0351] Examples 1 to 4 and Comparative Example 1

[0352] The aforementioned components A), B) and C) were blended in the amounts reported in Table 4 below, which also reports the final properties of the resulting polyolefin composition.

[0353] The mixture was blended with a conventional composition containing stabilizing additives under nitrogen atmosphere in a twin-screw extruder, Berstorff ZE 25 (screw length / diameter ratio: 34), under the following conditions:

[0354] Speed: 250 rpm;

[0355] Extruder output: 15 kg / hour;

[0356] Melting temperature: 245℃.

[0357] The composition of the stabilizing additive consists of 500 ppm of Irganox 1010, commercially available from BASF pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), 1000 ppm of Irgafos 168, commercially available from BASF tris(2,4-di-tert-butylphenyl) phosphite, 500 ppm of calcium stearate, and 1000 ppm of GMS90 (glyceryl monostearate), commercially available from Croda, totaling 0.3% by weight of stabilizing additive relative to the total weight of the polyolefin composition.

[0358] Table 4

[0359] Instance number 1 2 3 4 Composition 1 A) Quantity* weight% 99.475 99.455 99.475 99.455 99.52 B)-I quantity* weight% 0.065 0.065 - - - B)-II quantity* weight% - - 0.065 0.065 - C) Quantity* weight% 0.16 0.18 0.16 0.18 0.18 additive* weight% 0.3 0.3 0.3 0.3 0.3 A) Quantity** weight% 99.774 99.754 99.774 99.754 99.819 B)-I quantity** weight% 0.065 0.065 - - - B)-II quantity** weight% - - 0.065 0.065 - C) Quantity** weight% 0.16 0.18 0.16 0.18 0.18 Haze ％ 10.90 10.10 10.60 9.21 14.80 60° gloss GU 134.0 132.0 134.0 136.0 136.0 tensile modulus <![CDATA[N / mm 2 ]]> 1110 1155 1120 1136 Charpy gap at 23°C <![CDATA[kJ / m 2 ]]> 4.4 3.9 - 4.4 4.6 Charpy gap at 0°C <![CDATA[kJ / m 2 ]]> 1.5 1.7 - 1.5 1.4 Yield tensile stress <![CDATA[N / mm 2 ]]> 27.9 28.7 - 28.3 28.8 Yield elongation ％ 13.5 13.3 - 13.3 13.2 Fracture tensile stress <![CDATA[N / mm 2 ]]> 15.6 13.0 - 16.3 12.0 Elongation at break ％ 840.0 752.0 - 720.0 676.0 Melting temperature ℃ 147.5 148.2 147.9 148.2 147.9 Crystallization temperature ℃ 116.8 117.4 117.5 117.3 117.1

[0360] *Relative to the total weight of the polyolefin composition;

[0361] **Relative to the total weight of A)+B)+C).

Claims

1. A polyolefin composition comprising: A) from 99.5 to 99.88 wt% of a propylene polymer; B) from 0.02 to 0.2 wt% of a butene-1 polymer; and C) a clarifying agent; wherein the amounts of A) and B) are relative to the total weight of A) + B) + C).

2. The polyolefin composition according to claim 1 having a haze value equal to or lower than 20% measured according to ASTM D 1003 - 13 on 1 mm plaques.

3. The polyolefin composition according to claim 1 or 2 comprising: A) from 99.5 to 99.88 wt% of a propylene polymer; B) from 0.02 to 0.2 wt% of a butene-1 polymer; and C) from 0.02 to 0.3 wt% of a clarifying agent; wherein the amounts of A), B) and C) are relative to the total weight of A) + B) + C).

4. The polyolefin composition according to claim 1 or 2 wherein the weight ratio C) / B) is from 0.5 to 4.

5. The polyolefin composition according to claim 1 or 2 having a MIL from 0.1 to 400 g / 10 min, wherein MIL is the melt flow index determined according to ISO 1133-2:2011 at 230 °C and 2.16 kg load.

6. The polyolefin composition according to claim 1 or 2 wherein the propylene polymer A) is selected from propylene homopolymers, propylene copolymers and mixtures thereof, and the butene-1 polymer B) is selected from butene-1 homopolymers, butene-1 copolymers and mixtures thereof.

7. The polyolefin composition according to claim 6 wherein the propylene polymer A) has at least one of the following additional features: - when A) is a copolymer, the content of comonomer is from 0.5 to 15 wt%; - the polydispersity index (P.I.) is equal to or higher than 4; - the MIL is from 0.1 to 400 g / 10 min; - the amount of fraction insoluble in xylene at 25 °C is equal to or higher than 85 wt%; - the flexural modulus is higher than 200 MPa.

8. The polyolefin composition according to claim 1 or 2 wherein the butene-1 polymer B) has a MIE value from 1 to 3000 g / 10 min, wherein MIE is the melt flow index determined according to ISO 1133-2:2011 at 190 °C and 2.16 kg load.

9. The polyolefin composition according to claim 1 or 2 wherein the butene-1 polymer B) has a comonomer content of copolymerization from 0.5 to 4.0 mol%.

10. The polyolefin composition according to claim 1 or 2 wherein the butene-1 polymer B) has at least one of the following additional features: a) the molecular weight distribution (Mw / Mn) is equal to or lower than 9; b) the melting point Tmll measured by DSC (Differential Scanning Calorimetry) in the second heating run with a scan rate of 10 °C / min is equal to or lower than 125 °C; c) a Brookfield viscosity at 190 °C from 1500 to 20000 mPa-sec; d) using a 150.91 MHz operating 13 C-NMR no 4,1 insertion detectable; e) an X-ray crystallinity from 25 to 65%; f) a glass transition temperature (Tg) from -40 °C to -10 °C.

11. The polyolefin composition according to claim 1 or 2, wherein the clarifying agent C) is selected from the group consisting of derivatives of polyols, phosphoric acid ester salts and carboxylic acid salts.

12. The polyolefin composition according to claim 11, wherein the clarifying agent C) is selected from the group consisting of di(alkylbenzylidene)sorbitol, bis(3,4-dialkylbenzylidene)sorbitol and nonanol derivatives.

13. An article comprising the polyolefin composition according to claim 1 or 2.

14. The article according to claim 13, wherein the article is an injection molded article.

15. Use of a butene-1 polymer B) for reducing the haze of a polyolefin composition, said polyolefin composition comprising: A) from 99.5 wt% to 99.88 wt% of a propylene polymer; and C) a clarifying agent; said butene-1 polymer B) being added to the polyolefin composition in an amount from 0.02 wt% to 0.2 wt% with respect to the total weight of A) + B) + C).

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