Blow-molding polyethylene compositions with improved swelling behavior

Abstract

1. A polyethylene composition particularly suitable for the production of blow-molded hollow articles, comprising: 1) Density is 0.955g / cm 3 is greater than or equal to 0.965, 2) MIF / MIE ratio is 60-125. 3) MIF is 15-40g / 10min. 4) The ER value is 3.0 to 5.5. 5)η 0.02 It has the characteristic that the viscosity is 150,000 Pa.s or less.

Description

[Technical Field]

[0001] The present invention relates to polyethylene compositions suitable for the manufacture of small articles by blow molding. [Background technology]

[0002] EP 2818509 A1 discloses a polyethylene composition which has an improved balance of impact resistance and environmental stress crack resistance (ESCR) at low temperatures and is particularly suitable for producing protective coatings on metal pipes.

[0003] WO2010025342 A2 discloses a process for injection blow molding an article, the process comprising injecting into a mold cavity a composition comprising at least one ethylene-based polymer and 1000 ppm or less of a mold release agent, based on the total weight of the composition.

[0004] WO 2008 / 088464 A1 discloses a method for modifying polyethylene, in which ethylene or a mixture of ethylene and a C3-C10 alpha olefin is polymerized in an organic solvent with a Ziegler or single-site catalyst to form an initial polyethylene solution.

[0005] Examples of compositions suitable for said use are disclosed in WO 2018095700, WO 2018095701, and WO 2018095702.

[0006] By appropriately selecting its molecular structure and rheological behavior, the composition achieves particularly high environmental stress crack resistance (ESCR) over a wide density range, with reduced gel content, combined with an extremely smooth surface of the final article.

[0007] At high density levels, the ESCR is lower but still satisfactory.

[0008] However, an important aspect that needs to be optimized in blow molding is the swelling behavior of the polymer composition.

[0009] In fact, the overall quality level and consistency of the blow molded product is highly dependent on swelling.

[0010] For example, in extrusion blow molding, parison swell is very important.

[0011] Parison swell has two components: weight swell and diameter swell.

[0012] Gravimetric swelling can occur during the short time that the mold is open and the parison is dropping in. The parison may actually shrink in length while simultaneously thickening its walls and becoming heavier.

[0013] Too much weight swell must be avoided, especially for producing lightweight blown articles with thin, consistent wall thickness. Die adjustments can be important.

[0014] If the weight swelling of the resin used is too high, attempts are often made to reduce the weight by reducing the die gap.

[0015] However, reducing the die gap results in a very thin parison that can easily collapse or break.

[0016] Furthermore, a narrow die gap is extremely sensitive to impurities. A narrow die gap also results in high shear, which can lead to large diameter swelling in the parison. The final bottle may be intact but may be surrounded by heavy flash. Crimping can also be a problem.

[0017] Therefore, weight swell must be kept within practical limits relative to commonly used industry standards.

[0018] Diameter swelling causes the parison to bulge outward from the die, in other words, the diameter of the parison becomes significantly larger than the diameter of the die.

[0019] Diameter swell is particularly important for blow molded articles (especially bottles) that include handle portions, and is therefore commonly referred to as "handle wear."

[0020] In this case, the diameter swell can be expressed as the distance (length), for example in centimeters, that the burr extends from the neck of the handlewear item (including any protruding burrs) to the handle area and in some cases may extend beyond the handle area.

[0021] In fact, a resin with too little diameter swell can cause less handle webbing and in severe cases even a blowout.

[0022] In this case, the parison is caught in two places by the inner handle pinch-off.

[0023] Upon blowing, these areas come together to form a heavy area known as a web.

[0024] As previously mentioned, resins with too much diameter swell will produce an undesirable amount of flash and, consequently, deburring problems as well.

[0025] Consequently, it is very important to provide polyethylene compositions that inherently have good and consistent swelling behavior.

[0026] It is known that the swelling behavior of polyethylene compositions can be modified by treatment with radical initiators, particularly peroxides, as disclosed, for example, in US Pat. Nos. 4,603,173 and 5,486,575.

[0027] It has now been found that by properly designing the molecular structure and selected rheological properties of the polyethylene composition, for example by post-polymerization treatment with a radical initiator, a particularly favorable balance of parison swell and mechanical properties can be achieved while reducing gel content. Summary of the Invention

[0028] Thus, the present disclosure: 1) The MIF / MIE ratio is 60 to 125, preferably 62 to 123, where MIF is the melt flow index at 190°C under a load of 21.60 kg, and MIE is the melt flow index at 190°C under a load of 2.16 kg, both determined in accordance with ISO 1133-2:2011; 2) MIF is 15 to 40 g / 10 min, preferably 20 to 35 g / 10 min, or 25 to 40 g / 10 min, particularly 25 to 35 g / 10 min; 3) Density: 0.955 to 0.965 g / cm 3 , especially 0.956 to 0.960 g / cm 3 and measured at 23°C according to ISO 1183-1:2012, 4) The ER value is 3.0 to 5.5, or 3.5 to 5.5, preferably 3.0 to 5.2, or 3.5 to 5.2, more preferably 4.0 to 5.0, or 3.5 to 4.8, and most preferably 4.2 to 5.2, or 4.2 to 4.8; 5)η 0.02 is 150,000 Pa s or less, preferably 100,000 Pa s or less, more preferably 80,000 Pa s or less, particularly 150,000 to 25,000 Pa s, or 100,000 to 25,000 Pa s, or 80,000 to 25,000 Pa s or less; where η 0.02 was measured in a parallel plate (or so-called plate-plate) rheometer under dynamic oscillatory shear mode at an applied angular frequency of 0.02 rad / s. ℃ is the complex viscosity of the melt measured at a temperature ER is calculated as follows: ER=(1.781*10 -3 )*G' Here, G' = 5,000 dyn / cm 2 The value of where: G' = storage modulus, G'' = loss modulus, Both G' and G'' are measured by dynamic oscillatory shear in a plate-plate rotational rheometer at a temperature of 190°C.

[0029] The polyethylene composition meets industrial requirements in terms of weight swell and diameter swell and is therefore easily processable in conventional blow molding equipment. [Brief explanation of the drawings]

[0030] These and other features, aspects, and advantages of the present disclosure will become better understood with reference to the following description and appended claims, as well as the drawings.

[0031] [Figure 1] FIG. 1 is an exemplary embodiment of a simplified process flow diagram of two series-connected gas phase reactors suitable for use according to various embodiments of the ethylene polymerization process disclosed herein to produce various embodiments of the polyethylene compositions disclosed herein. [Figure 2] Figure 2 shows the test bottle used in the weight and diameter swelling test. The test bottle is approximately 28 cm high (excluding the top and bottom flash) and approximately 14 cm wide.

[0032] It should be understood that the various embodiments are not limited to the arrangements and instrumentality shown in the drawings. DETAILED DESCRIPTION OF THE INVENTION

[0033] The expression "polyethylene composition" is intended to alternatively include single ethylene polymers and ethylene polymer compositions, particularly compositions of two or more ethylene polymer components, preferably having different molecular weights; such compositions are also referred to in the art as "bimodal" or "multimodal" polymers.

[0034] Typically, the polyethylene composition of the present invention consists of or comprises one or more ethylene copolymers.

[0035] All properties defined herein, including characteristics 1) to 5) defined above, refer to the ethylene polymer or ethylene polymer composition. One or more of the above characteristics can be modified by the addition of other components, such as additives, commonly used in the art.

[0036] The MIF / MIE ratio provides a rheological measure of the molecular weight distribution.

[0037] Another measure of molecular weight distribution is the ratio M w / M n Provided by, where M w is the weight average molecular weight, M n is the number average molecular weight, measured by GPC (gel permeation chromatography).

[0038] Preferred M of the polyethylene composition w / M n The value is in the range of 15-35, especially 18-35.

[0039] M w The value is preferably between 150,000 g / mol and 450,000 g / mol, in particular between 150,000 g / mol and 350,000 g / mol.

[0040] Furthermore, the polyethylene composition of the present invention preferably comprises the comonomer content is less than or equal to 1.5% by weight (FTIR), in particular between 0.1 and 1.5% by weight, relative to the total weight of the composition; an MIP of at least 0.3 g / 10 min, more preferably at least 0.5 g / 10 min, in particular between 0.3 and 4 g / 10 min, or between 0.5 and 4 g / 10 min, where MIP is the melt flow index measured according to ISO 1133-1 2012-03 at 190°C under a load of 5 kg; - a (MIF / MIE)ER ratio between MIF / MIE and ER of 28 or less, in particular 28-15 or 28-18; a long chain branching index LCBI of at least 0.55, more preferably at least 0.62, the upper limit being preferably 0.95 in each case; where LCBI is the ratio of the measured mean square radius of gyration Rg to the mean square radius of gyration for linear PE of the same molecular weight at a molar weight of 1,000,000 g / mol, as measured by GPC-MALLS; -η 0.02 is 35,000 Pa s or more, more preferably 40,000 Pa s or more, particularly 35,000 or 40,000 to 70,000 Pa s; -ratio(η 0.02 / 1000) / LCBI, i.e., η 0.02 The value between the value obtained by dividing by 1000 and the LCBI is 50 to 100, more preferably 65 to 95. -HMWcopo index is 0.5 to 5, especially 0.5 to 3.5; wherein the HMWcopo index is determined according to the following formula: HMWcopo = (η 0.02 xt maxDSC ) / (10^5)

[0041] where t maxDSC is the time required to reach the maximum heat flow of crystallization (in mW) measured by differential scanning calorimetry (DSC) in isothermal mode at a temperature of 124°C under quiescent conditions (time to reach the maximum crystallization rate, equivalent to the t1 / 2 crystallization half-life), expressed in minutes.

[0042] The one or more comonomers present in ethylene copolymers are generally selected from α-olefins of the molecular formula CH2=CHR, where R is a linear or branched alkyl group containing from 1 to 10 carbon atoms.

[0043] Specific examples include propylene, butene-1, pentene-1, 4-methylpentene-1, hexene-1, octene-1, and decene-1. A particularly preferred comonomer is hexene-1.

[0044] Preferably, the polyethylene composition is obtained by using a Ziegler-Natta polymerization catalyst in the polymerization stage, details of which are provided hereinafter.

[0045] As previously mentioned, the polyethylene composition can be advantageously used to manufacture blow molded articles, particularly handleware such as bottles with handle portions having valuable properties.

[0046] Indeed, it is preferably characterized by an environmental stress crack resistance, measured by FNCT 6 MPa / 50° C., of at least 10 hours, preferably at least 15 hours, especially between 10 or 15 hours and 50 hours.

[0047] The gel content of the polyethylene composition is preferably 10 gels / m 2 less than 5 gels / m 2 Less than 3 gels / m 2 and have a diameter of more than 450 μm.

[0048] The total gel content is preferably 350 gels / m 2 less than 300 gels / m 2 is less than.

[0049] The swelling ratio of the present polyethylene composition is preferably 140% or more, particularly 140% to 190%.

[0050] Details of the test method are given in the Examples.

[0051] The blow molding process is generally carried out by first plasticizing the polyethylene composition in an extruder at a temperature ranging from 180°C to 250°C, and then extruding it through a die into a blow mold where it is cooled.

[0052] In a preferred embodiment, the polyethylene composition having the characteristics defined above has a MIF / MIE 1) smaller than 1), preferably between 50 and 119, more preferably between 60 and 110. I ), with a radical initiator, wherein the MIF / MIE ratio of the final polyethylene composition (after contact with said radical initiator) is 1) and the MIF / MIE ratio of said precursor polyethylene composition (I) is 1 I ) is the ratio 1) / 1 I ) is 1.05 or more, particularly 1.05 to 1.8, or 1.05 to 1.5.

[0053] Preferably, the ER of the final polyethylene composition (after contact with the radical initiator) is 4) and the ER of the precursor polyethylene composition (I) is 4 I ) is between the ratio 4) / 4 I ) is 1.1 to 2.5.

[0054] In a particularly preferred embodiment, the precursor polyethylene composition (I) 2 I ) MIF is 20 to 50 g / 10 min, preferably 25 to 45 g / 10 min; 3 I ) density is 0.955g / cm 3 Greater than 0.965g / cm3 or less, especially 0.956~0.960g / cm 3 That is, 4 I ) the ER value is 2 to 4, preferably 2 to 3.5; 5 I )η 0.02has the additional feature of being 150,000 Pa.s or less, preferably 100,000 Pa.s or less, more preferably 80,000 Pa.s or less, especially 150,000 to 15,000 Pa.s, or 100,000 to 21,000 Pa.s, or 80,000 to 15,000 Pa.s.

[0055] Furthermore, the precursor polyethylene composition (I) preferably comprises: a comonomer content of not more than 1.5 wt.%, in particular 0.1 to 1.5 wt.% (FTIR) relative to the total weight of the composition, the comonomer(s) being the same as those reported above for the final polyethylene composition, in particular the type and amount of the comonomer(s) being the same in the final polyethylene composition (after contact with the radical initiator) and in its precursor polyethylene composition (I), - MIP is 0.3 g / 10 min or more, more preferably 0.5 g / 10 min or more, in particular 0.3 to 6 g / 10 min or 0.5 to 6 g / 10 min, a (MIF / MIE) / ER ratio between MIF / MIE and ER of 28 or more, more preferably 29 or more, in particular 28-40, or 29-40, or 28-35, or 29-35; the long chain branching index LCBI is 0.50 or more, more preferably 0.55 or more, with the upper limit preferably being 0.90 for all classes; -η 0.02 is 45,000 Pa.s or less, especially 45,000 to 20,000 Pa.s. -ratio(η 0.02 / 1000) / LCBI, i.e., η 0.02 The value between the value obtained by dividing by 1000 and the LCBI is 45 to 80, more preferably 50 to 75. - an HMWcopo index of 0.5 to 3, in particular 0.5 to 3.5.

[0056] In a particularly preferred embodiment, the precursor polyethylene composition (I) A) 30 to 70% by weight, preferably 40 to 60% by weight, of an ethylene homopolymer or copolymer (homopolymer is preferred) having a density of 0.960 g / cm 3 or more, and according to ISO 1333, the melt flow index MIE at 190 ° C under a load of 2.16 kg is 8 g / 10 min or more, preferably 40 g / 10 min or more; B) 30 to 70% by weight, preferably 40 to 60% by weight, of an ethylene copolymer having an MIE value less than that of A), preferably less than 0.5 g / 10 min.

[0057] The percentage amounts are given relative to the total weight of A)+B).

[0058] Specific MIE ranges for component A) are as follows: -8~150g / 10min, or -40~150g / 10min, or -8~120g / 10min, or -40~120g / 10min.

[0059] It has been discovered that the precursor polyethylene composition (I) can be prepared by a gas phase polymerization process in the presence of a Ziegler-Natta catalyst.

[0060] Ziegler-Natta catalysts consist of the reaction product of an organometallic compound from Groups 1, 2 or 13 of the Periodic Table of Elements with a transition metal compound from Groups 4 to 10 of the Periodic Table of Elements (new notation). In particular, the transition metal compound can be selected from compounds of Ti, V, Zr, Cr and Hf, preferably supported on MgCl2.

[0061] Preferred organometallic compounds are organoaluminum compounds.

[0062] Thus, in a preferred embodiment, the precursor polyethylene composition (I) is obtainable using a Ziegler-Natta polymerization catalyst, preferably a Ziegler-Natta catalyst comprising the reaction product of:

[0063] A) a solid catalyst component comprising Ti, Mg, chlorine, and one or more internal electron donor compounds ED; B) an organoaluminum compound, and optionally C) External electron donor compound ED ext .

[0064] In particular, the solid catalyst component A) comprises one internal electron donor ED selected from esters of aliphatic monocarboxylic acids (EAA) and another internal donor ED selected from cyclic ethers (CE). I and CE in an amount such that the EAA / CE molar ratio is in the range of 0.02 to less than 20.

[0065] Preferably, the EAA / CE molar ratio is in the range of 0.2 to 16, more preferably 0.5 to 1.0.

[0066] Internal electron donor compounds (EAA) are C1-C 10 , preferably C2-C 10 Preferably, the alkyl ester is selected from C2-C5 alkyl esters of C2-C6 aliphatic monocarboxylic acids, and more preferably C2-C6 aliphatic monocarboxylic acids. Among these, ethyl acetate is particularly preferred.

[0067] The (CE) internal donor is preferably selected from cyclic ethers having 3 to 5 carbon atoms, of which tetrahydrofuran, tetrahydropyran, and dioxane are most preferred, with tetrahydrofuran being particularly preferred.

[0068] The (EAA+CE) / Ti molar ratio is preferably greater than 1.5, more preferably in the range of 2.0-10, particularly 2.5-8.

[0069] The content of (EAA) is usually 1 to 30 wt %, more preferably 2 to 20 wt %, based on the total weight of the solid catalyst component. The content of (CE) is usually 1 to 20 wt %, more preferably 2 to 10 wt %, based on the total weight of the solid catalyst component.

[0070] The Mg / Ti molar ratio is preferably in the range of 5 to 50, more preferably in the range of 10 to 40.

[0071] As discussed above, the catalyst component contains Ti, Mg, and chlorine in addition to the electron donor compound. The Ti atoms preferably originate from a Ti compound containing at least a Ti-halogen bond, and the Mg atoms preferably originate from magnesium dichloride. Preferred titanium compounds are tetrahalides or compounds of the formula TiX n (OR 1 ) 4-n where 0 < n < 3, X is a halogen, preferably chlorine, and R 1 is a C1-C 10 hydrocarbon group. Titanium tetrachloride is a preferred titanium compound.

[0072] The catalyst component of the present disclosure can be prepared according to various methods.

[0073] [[ID=2l]] One preferred method is: (a) contacting MgX2(R 2 OH) m adduct (where the R 2 group is a C1-C 20 ]]hydrocarbon group and X is a halogen) with a liquid medium containing a Ti compound having at least a Ti-Cl bond in an amount such that the Ti / Mg molar ratio exceeds 3, thereby forming a solid intermediate; and (b) contacting the internal donor compounds (EEA) and (CE) defined previously with the solid intermediate resulting from (a), and then washing the resulting product.

[0074] A preferred starting MgX2(R 2 OH)<\ m adduct is one in which the R 2 group is C1-C 10where X is an alkyl group, X is chlorine, and m is 0.5 to 4, more preferably 0.5 to 2. This type of adduct can generally be obtained by mixing an alcohol and magnesium chloride in the presence of an inert hydrocarbon immiscible with the adduct and stirring at the melting temperature of the adduct (100 to 130°C). The emulsion is then rapidly quenched, thereby solidifying the adduct in the form of spherical particles. Representative methods for producing these spherical adducts are reported, for example, in U.S. Pat. Nos. 4,469,648, 4,399,054, and WO 98 / 44009. Another method that can be used for spheronization is the spray cooling method, described, for example, in U.S. Pat. Nos. 5,100,849 and 4,829,034.

[0075] Of particular interest is MgCl2(EtOH) m The adducts, in which m is in the range of 0.15 to 1.5 and the particle size is in the range of 10 to 100 μm, and which have a higher alcohol content, are obtained by thermal dealcoholization treatment in a nitrogen stream at temperatures of 50 to 150° C. until the alcohol content is reduced to the aforementioned value. A process of this type is described in EP 395083.

[0076] Dealcoholation can also be accomplished chemically by contacting the adduct with a compound capable of reacting with the alcohol group.

[0077] In general, these dealcoholized adducts are also characterized by their porosity, measured by the mercury method, with porosity ranging from 0.15 to 2.5 cm due to pores with a radius of up to 1 μm. 3 / g, preferably 0.25 to 1.5 cm 3 / g range.

[0078] The reaction with the Ti compound can be carried out by suspending the adduct in TiCl4 (typically cooled), followed by heating the mixture to a temperature in the range of 80-130°C and maintaining this temperature for 0.5-2 hours. The treatment with the titanium compound can be carried out one or more times. Preferably, the treatment is carried out twice. At the end of the process, the intermediate solid is recovered by separating the suspension by conventional methods (settling and removing the liquid, filtration, centrifugation, etc.) and can be washed with a solvent. Washing is typically carried out with an inert hydrocarbon liquid, although more polar solvents (e.g., with a higher dielectric constant), such as halogenated hydrocarbons, can also be used.

[0079] As described above, in step (b), the intermediate solid is contacted with an internal donor compound in an amount such that the EAA / CE molar ratio is in the range of 0.02 to less than 20, under conditions such that the internal donor compound is immobilized on the solid.

[0080] Although not strictly necessary, the contacting is usually carried out in a liquid medium such as a liquid hydrocarbon. The temperature at which the contacting occurs varies depending on the nature of the reagents. It is generally in the range of -10 to 150°C, preferably 0 to 120°C. Obviously, temperatures that cause decomposition or degradation of a particular reagent should generally be avoided, even within the appropriate range. The treatment time can also vary depending on other conditions, such as the nature, temperature, and concentration of the reagents. As a general guide, this contacting step can last from 10 minutes to 10 hours, more often from 0.5 to 5 hours. If desired, this step can be repeated one or more times to further increase the final donor content.

[0081] At the end of this step, the solids are recovered by separating the suspension by conventional methods (settling and removal of the liquid, filtration, centrifugation, etc.) and can be washed with a solvent. Washing is typically done with an inert hydrocarbon liquid, although more polar solvents (e.g., with a higher dielectric constant), such as halogenated or oxygenated hydrocarbons, can also be used.

[0082] According to a particular embodiment, it is particularly preferred to carry out step (b) followed by a further step (c) by subjecting the solid catalyst component derived from (b) to a heat treatment carried out at a temperature between 70 and 150° C.

[0083] In step (c) of the process, the solid product recovered from step (b) is subjected to a heat treatment carried out in the temperature range of 70 to 150°C, preferably 80 to 130°C, more preferably 85 to 100°C.

[0084] The heat treatment can be carried out in several ways, according to one of which the solid from step (b) is suspended in an inert diluent such as a hydrocarbon and then subjected to heating while keeping the system under stirring.

[0085] According to an alternative technique, the solids can be heated in the dry state by inserting them into an apparatus with jacketed heated walls. Agitation can be achieved by a mechanical stirrer placed in said apparatus, but it is preferred to use a rotating device to induce agitation.

[0086] According to yet another embodiment, the solids from (b) may be heated by passing a stream of hot inert gas, such as nitrogen, through them, preferably by maintaining the solids under fluidized conditions.

[0087] The heating time is not fixed but may vary depending on other conditions, such as the maximum temperature reached. Generally, the heating time ranges from 0.1 to 10 hours, more specifically, from 0.5 to 6 hours. Generally, the higher the temperature, the shorter the heating time; the lower the temperature, the longer the reaction time.

[0088] In the described process, each of steps (b)-(c) can be performed immediately after the previous step without requiring isolation of the solid product from the previous step. However, if desired, the solid product from a step can be isolated and washed before being passed on to a subsequent step.

[0089] According to a particular embodiment, a preferred modification of the process comprises subjecting the solids resulting from step (a) to a prepolymerization step (a2) before carrying out step (b).

[0090] The prepolymerization is carried out by preparing an olefin CH═CHR (where R is H or C1-C 10 The prepolymerization step can be carried out in either a liquid or gas phase (wherein the polymer is a hydrocarbon group). It is particularly preferred to prepolymerize ethylene or propylene or a mixture thereof with one or more α-olefins, the mixture containing up to 20 mol% of α-olefin, to form a polymer in an amount of from about 0.1 g to about 1000 g per gram of solid intermediate, preferably from about 0.5 to about 500 g per gram of solid intermediate, more preferably from 0.5 to 50 g per gram of solid intermediate, and especially from 0.5 to 5 g per gram of solid intermediate. The prepolymerization step can be carried out at a temperature of 0 to 80°C, preferably from 5 to 70°C, in either a liquid or gas phase. It is particularly preferred to prepolymerize the intermediate with ethylene or propylene to produce a polymer in an amount of from 0.5 to 20 g per gram of intermediate. The prepolymerization is carried out using a suitable cocatalyst, such as an organoaluminum compound. When the solid intermediate is prepolymerized with propylene, the prepolymerization is preferably carried out using a compound represented by the general formula R a 4 R b 5 Si(OR 6 ) c wherein a and b are integers from 0 to 2, c is an integer from 1 to 3, the sum (a+b+c) is 4, and R 4 , R 5 , and R 6 is an alkyl, cycloalkyl, or aryl radical having 1 to 18 carbon atoms, optionally containing heteroatoms; a is 1, b is 1, c is 2, and R 4 and R 5 at least one of R is selected from a branched alkyl, cycloalkyl, or aryl group having 3 to 10 carbon atoms, optionally containing heteroatoms; 6 is C1-C10 Silicon compounds having alkyl groups, especially methyl groups, are particularly preferred. Examples of such silicon compounds are methylcyclohexyldimethoxysilane (C donor), diphenyldimethoxysilane, methyl-t-butyldimethoxysilane, dicyclopentyldimethoxysilane (D donor), and diisopropyldimethoxysilane.

[0091] All of the above processes are suitable for preparing particles of a solid catalyst component having a substantially spherical morphology and an average diameter of 5 to 150 μm, preferably 10 to 100 μm. By particles having a substantially spherical morphology, we mean particles having a ratio of major axis to minor axis of 1.5 or less, preferably 1.3 or less.

[0092] Generally, the solid catalyst component obtained according to the above method is generally 10 to 200 m 2 / g, preferably 20 to 80m 2 / g surface area (BTE method) and 0.15 cm 3 / g or larger, preferably 0.2 to 0.6 cm 3 The total porosity (BTE method) is shown as 0.25 to 1 cm / g. The porosity (Hg method) due to pores with a radius of up to 10,000 Å is generally 0.25 to 1 cm. 3 / g, preferably 0.35 to 0.8 cm 3 / g range.

[0093] As previously described, the catalyst component of the present disclosure reacts with an Al-alkyl compound to form a polymerization catalyst. In particular, Al-trialkyl compounds, such as Al-trimethyl, Al-triethyl, Al-tri-n-butyl, and Al-triisobutyl, are preferred. The Al / Ti ratio is greater than 1, typically between 5 and 800.

[0094] Alternatively, alkylaluminum halides can be used, particularly alkylaluminum chlorides such as diethylaluminum chloride (DEAC), diisobutylaluminum chloride, Al-sesquichloride, and dimethylaluminum chloride (DMAC). Mixtures of trialkylaluminum compounds with alkylaluminum halides can also be used, and are preferred in certain cases. Among these, TEAL / DEAC and TIBA / DEAC are particularly preferred.

[0095] Optionally, an external electron donor (DE ext ) can be used during the polymerization. The external electron donor compound may be the same as or different from the internal donor used in the solid catalyst component. It is preferably selected from the group consisting of ethers, esters, amines, ketones, nitriles, silanes and mixtures thereof. In particular, C2-C 20 The ether can be advantageously selected from the above aliphatic ethers, particularly preferably from cyclic ethers having 3 to 5 carbon atoms such as tetrahydrofuran and dioxane.

[0096] an aluminum alkyl cocatalyst (B), and an external electron donor (ED) as component (C); ext In addition to the possibility of using halogenated compounds (D), halogenated compounds (D) can be used as activity enhancers. The compounds are preferably monohalogenated or dihalogenated hydrocarbons. In a preferred embodiment, the compounds are selected from monohalogenated hydrocarbons in which the halogen is bonded to a secondary carbon atom. The halogen is preferably selected from chloride and bromide.

[0097] Non-limiting exemplary compounds for (D) are propyl chloride, i-propyl chloride, butyl chloride, s-butyl chloride, t-butyl chloride, 2-chlorobutane, cyclopentyl chloride, cyclohexyl chloride, 1,2-dichloroethane, 1,6-dichlorohexane, propyl bromide, i-propyl bromide, butyl bromide, s-butyl bromide, t-butyl bromide, i-butyl bromide, i-pentyl bromide, and t-pentyl bromide. Among these, i-propyl chloride, 2-chlorobutane, cyclopentyl chloride, cyclohexyl chloride, 1,4-dichlorobutane, and 2-bromopropane are particularly preferred.

[0098] According to another embodiment, the compound may be selected from among halogenated alcohols, esters, or ethers, such as 2,2,2-trichloroethanol, ethyl trichloroacetate, butyl perchlorocrotonate, 2-chloropropionate, and 2-chloro-tetrahydrofuran.

[0099] The activity enhancer can be used in an amount such that the (B) / (D) molar ratio is greater than 3, preferably in the range of 5-50, more preferably in the range of 10-40.

[0100] The above-mentioned components (A) to (D) can be fed separately to the reactor under polymerization conditions to utilize their activity. However, in a particularly advantageous embodiment, this constitutes pre-contacting of the components, optionally in the presence of a small amount of olefin, for a period ranging from 1 minute to 10 hours, preferably from 2 to 7 hours. Pre-contacting can be carried out in a liquid diluent at a temperature ranging from 0 to 90°C, preferably from 20 to 70°C.

[0101] One or more alkylaluminum compounds, or a mixture thereof, can be used in the precontacting. When two or more alkylaluminum compounds are used in the precontacting, they can be used together or can be added successively to the precontacting tank. When precontacting is carried out, it is not necessary to add the entire amount of aluminum alkyl compound at this stage. A portion of it can be added in the precontacting, while the remaining aliquot can be fed to the polymerization reactor. Furthermore, when two or more aluminum alkyl compounds are used, it is also possible to use one or more in the precontacting process and feed the other(s) to the reactor.

[0102] In one preferred embodiment, the precontacting is carried out by first contacting the catalyst components with an aluminum trialkyl, such as tri-n-hexylaluminum (THA), then adding another aluminum alkyl compound, preferably diethylaluminum chloride, to the mixture, and finally adding another trialkylaluminum, preferably triethylaluminum, as a third component to the precontacted mixture. According to a variation of this process, the last aluminum trialkyl is added to the polymerization reactor.

[0103] The total amount of aluminum alkyl compound used can vary within a wide range, but is preferably in the range of 2 to 10 moles per mole of the internal donor in the solid catalyst component.

[0104] It has been found that by using the above-described polymerization catalyst, the precursor polyethylene composition (I) can be prepared by a process comprising the following steps, in any order relative to one another:

[0105] a) polymerizing ethylene in a gas phase reactor in the presence of hydrogen, optionally with one or more comonomers; b) copolymerizing ethylene with one or more comonomers in a separate gas phase reactor in the presence of hydrogen in amounts less than in step a).

[0106] Here, in at least one of said gas phase reactors, grown polymer particles flow upward under fast flow or transport conditions through a first polymerization zone (riser), exit said riser and enter a second polymerization zone (downcomer), flow downward through the second polymerization zone by gravity, exit said downcomer and be reintroduced into the riser, establishing a polymer circulation between said two polymerization zones.

[0107] In the first polymerization zone (riser), rapid fluidization conditions are established by feeding a gas mixture containing one or more α-olefins (ethylene and comonomers) at a velocity faster than the transport velocity of the polymer particles. The velocity of the mixed gas is preferably between 0.5 and 15 m / sec, more preferably between 0.8 and 5 m / sec. The terms "transport velocity" and "fast fluidization conditions" are well known in the art. For their definitions, see, for example, D. Geldart, Gas Fluidization Technology, p. 155 et seq., J. Wiley & Sons Ltd., 1986.

[0108] In the second polymerization zone (downcomer), the polymer particles flow densely by gravity, resulting in a high solid density (polymer mass per reactor volume) that is close to the bulk density of the polymer.

[0109] In other words, the polymer flows vertically downward through the downcomer in plug flow (pack flow mode), so that only a small amount of gas is entrapped between the polymer particles.

[0110] Such a process makes it possible to obtain from step a) an ethylene polymer having a lower molecular weight than the ethylene copolymer obtained from step b).

[0111] Preferably, ethylene is copolymerized to produce a relatively low molecular weight ethylene copolymer (step a) upstream of ethylene copolymerization to produce a relatively high molecular weight ethylene copolymer (step b). To this end, in step a), a mixed gas containing ethylene, hydrogen, a comonomer, and an inert gas is supplied to a first gas-phase reactor, preferably a gas-phase fluidized bed reactor. The polymerization is carried out in the presence of the aforementioned Ziegler-Natta catalyst.

[0112] Hydrogen is supplied in an amount that depends on the specific catalyst used, particularly in an amount suitable for obtaining an ethylene polymer having a melt flow index (MIE) of 8 g / 10 min or more in step a). To achieve this MIE range, step a) specifies a hydrogen / ethylene molar ratio of 1 to 4, and the amount of ethylene monomer is 2 to 20% by volume, preferably 5 to 15% by volume, relative to the total volume of gas present in the polymerization reactor. The remainder of the feed mixture is represented by an inert gas and one or more comonomers (if present). The inert gas required to dissipate the heat generated in the polymerization reaction can be easily selected from nitrogen or saturated hydrocarbons, most preferably propane.

[0113] The operating temperature in the reactor in step a) is 50 to 120°C, preferably 65 to 100°C, and the operating pressure is 0.5 to 10 MPa, preferably 2.0 to 3.5 MPa.

[0114] In a preferred embodiment, the ethylene polymer obtained in step a) preferably represents 30 to 70% by weight of the total ethylene polymer produced throughout the process, for example in the first and second reactors connected in series.

[0115] Next, the ethylene polymer and entrained gas from step a) are passed through a solid / gas separation step to prevent the mixed gas from the first polymerization reactor from entering the reactor for step b) (the second gas-phase polymerization reactor). The gas mixture can be recycled to the first polymerization reactor, and the separated ethylene polymer is fed to the reactor for step b). A suitable point for feeding the polymer to the second reactor is at the junction between the downcomer and the riser, where the solids concentration is particularly low and does not adversely affect the flow conditions.

[0116] The operating temperature of step b) is in the range of 65-95°C, and the pressure is in the range of 1.5-4.0 MPa. The second gas-phase reactor is intended to produce relatively high molecular weight ethylene copolymers by copolymerizing ethylene with one or more comonomers. To broaden the molecular weight distribution of the final ethylene polymer, the step b) reactor can be easily operated by varying the monomer and hydrogen concentration conditions in the riser and downcomer.

[0117] To this end, in step b), the gas mixture coming from the riser entrained with polymer particles can be partially or completely prevented from entering the downcomer, thereby obtaining two zones with different gas compositions. This can be achieved by supplying a gas and / or liquid mixture to the downcomer through a line located at a suitable point in the downcomer, preferably at its upper portion. The gas and / or liquid mixture must have a suitable composition different from that of the gas mixture present in the riser. The flow of the gas and / or liquid mixture can be adjusted so that the upward gas flow countercurrent to the flow of polymer particles, particularly at its top, acts as a barrier to the gas mixture entrained with polymer particles from the riser. In particular, it is advantageous to supply a mixture with a low hydrogen content to produce a higher molecular weight polymer fraction in the downcomer. One or more comonomers may optionally be supplied to the downcomer in step b) together with ethylene, propane, or other inert gases.

[0118] The hydrogen / ethylene molar ratio in the downcomer in step b) ranges from 0.005 to 0.2, the ethylene concentration is 0.5 to 15 volume %, preferably 0.5 to 10 volume %, and the comonomer concentration is 0.05 to 1.5 volume %, based on the total volume of gas present in the downcomer. The remainder is propane or a similar inert gas. Because a very low molar concentration of hydrogen is present in the downcomer, by carrying out the process of the present invention, it is possible to combine a relatively large amount of comonomer with the high molecular weight polyethylene fraction.

[0119] The polymer particles coming from the downcomer are reintroduced into the riser in step b).

[0120] As the polymer particles continue to react and no more comonomer is fed to the riser, the comonomer concentration drops to a range of 0.02-1.2% by volume, based on the total volume of gas present in the riser. In practice, the comonomer content is controlled to obtain the desired density of the final polyethylene. In the riser of step b), the hydrogen / ethylene molar ratio is in the range of 0.01-0.5, and the ethylene concentration is in the range of 5-20% by volume, based on the total volume of gas present in the riser. The remainder is propane or other inert gas.

[0121] Further details regarding the above polymerization process are provided in WO2005019280.

[0122] The precursor polyethylene composition (I) thus obtained is then contacted with a radical initiator.

[0123] By "contacted" it is meant that the precursor polyethylene composition (I) and the radical initiator are mixed together and react with each other.

[0124] The radical initiator is preferably selected from organic peroxides.

[0125] Particularly useful organic peroxides are organic monoperoxides and / or organic diperoxides. These organic monoperoxides and diperoxides can have a half-life of 1 hour at temperatures ranging from about 125°C to about 145°C, alternatively from about 130°C to about 140°C, or alternatively from about 132°C to about 136°C. Further alternatives include organic peroxides having a half-life of 0.1 hours at temperatures ranging from about 145°C to about 165°C, alternatively from about 150°C to about 160°C, or alternatively from about 154°C to about 158°C. The organic peroxides can have a molecular weight ranging from about 175 g / mol to about 375 g / mol, alternatively from about 200 g / mol to about 350 g / mol. Mixtures of two or more peroxides can be used if desired.

[0126] Suitable organic peroxides include, but are not limited to, dicumyl peroxide, di-tert-butyl peroxide, tert-butyl peroxybenzoate, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 3,6,9-triethyl-3,6,9-trimethyl-1,2,4,5,7,8-hexoxonane, representative examples of 3,6,9-trimethyl-3,6,9-tris(alkyl)-1,2,4,5,7,8-hexoxonane in which the alkyl group is propyl or ethyl, tert-butyl peroxyneodecanoate, tert-amyl peroxypivalate, 1,3-bis(tert-butylperoxyisopropyl)benzene, and the like.

[0127] Preferably, the organic peroxide is 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 3,6,9-triethyl-3,6,9-trimethyl-1,2,4,5,7,8-hexane, or, typically, 3,6,9-trimethyl-3,6,9-tris(alkyl)-1,2,4,5,7,8-hexane, where alkyl is propyl or ethyl.

[0128] In a preferred embodiment of the present disclosure, the organic peroxide is used in the form of a polyolefin mixture, which is preferably prepared by adding the organic peroxide in pure form or as a solution in a diluent such as a hydrocarbon to a polyolefin powder. Preferred polyolefin mixtures have an organic peroxide content in the polyolefin mixture ranging from 0.5 to 25 wt %, preferably from 1 to 20 wt %, more preferably from 2 to 10 wt %.

[0129] Preferably, the amount of organic peroxide added corresponds to a content of the reaction initiator in the precursor polyethylene composition (I) of 10 to 100 ppm by weight, more preferably 15 to 90 ppm by weight, particularly 15 to 80 ppm by weight, or 15 to 50 ppm by weight.

[0130] Contact with the radical initiator can be carried out by any means and under conditions well known in the art to be effective for radical-initiated reactions with olefin polymers.

[0131] It is known that such conditions can be carried out in conventional equipment commonly used to process polymers in the molten state.

[0132] In particular, the polyethylene composition of the present disclosure can be prepared by contacting the precursor polyethylene composition (I) with a radical initiator in an extrusion device. Suitable extrusion devices are extruders or continuous mixers. These extruders or mixers are single- or two-stage machines that melt and homogenize the polyethylene composition. Examples of extruders include pin-type extruders, planetary extruders, co-rotating disc processors, etc. Other possibilities include the combination of a mixer with a discharge screw and / or a gear pump. Preferred extruders are screw extruders, especially those configured as twin-screw machines. Particularly preferred are twin-screw extruders with discharge elements and continuous mixers, especially continuous mixers with counter-rotating rotors, or extrusion devices comprising at least one co-rotating twin-screw extruder. Machines of this type are common in the plastics industry and are manufactured, for example, by Coperion GmbH, Stuttgart, Germany; KraussMaffei Berstorff GmbH, Hannover, Germany; The Japan Steel Works, Tokyo, Japan; Farrel, Ansonia, USA; or Kobe Steel, Ltd., Japan. Suitable extruder equipment is usually further equipped with a unit for pelletizing the melt, such as an underwater pelletizer.

[0133] The contact and reaction temperature is preferably in the range of 180 to 350°C, particularly 180 to 300°C, and is usually equal to or higher than the decomposition temperature of the radical reaction initiator.

[0134] In most operations, particularly large-scale operations, contact and reaction times of several initiator half-lives are preferred. This results in a substantially complete reaction and minimizes the possibility of undesirable initiator residues in the polyethylene composition. While small amounts of undecomposed initiator are not harmful, the presence of significant amounts of unreacted initiator can lead to gel formation and other undesirable effects during subsequent processing of the polyethylene composition.

[0135] Additionally, one or more additives may be provided in the polyethylene composition.

[0136] These additives can be added before, during, or after contacting the precursor polyethylene composition (I) with the radical initiator.

[0137] Such additives are common in the art. Suitable types of additives for preparing polyethylene compositions are, for example, antioxidants, melt stabilizers, light stabilizers, acid scavengers, lubricants, processing aids, antiblocking agents, slip agents, antistatic agents, antifogging agents, pigments or dyes, nucleating agents, flame retardants, or fillers. It is common for multiple additives to be added. The multiple additives may be of different types. However, it is also possible to add several representatives of one type of additive to the polyethylene composition. All of these types of additives are generally commercially available and are described, for example, in "Handbook of Plastic Additives," by Hans Zweifel, 5th edition, Munich, 2001. Example

[0138] Examples and advantages of the various embodiments, compositions, and methods provided herein are disclosed in the following examples, which are merely illustrative and are not intended to limit the scope of the appended claims in any way.

[0139] The following analytical methods are used to characterize the polymer compositions. Melt Flow Index

[0140] Measured at 190°C and a specified load according to ISO 1133-2:2011. density

[0141] Measured at 23°C according to ISO 1183-1:2012. Molecular weight distribution measurement

[0142] Measurement of the average Mw and Mn values, and the resulting Mw / Mn ratio, was performed by high-temperature gel permeation chromatography (HPC) according to ISO 16014-1, -2, and -4, 2003. Specific conditions based on the ISO standard were as follows: solvent: 1,2,4-trichlorobenzene (TCB), apparatus and solution temperature: 135°C, concentration detector: PolymerChar IR-4 infrared detector (Valencia, Paterna 46980, Spain) compatible with TCB. A WATERS Alliance 2000 was used, equipped with a SHODEX UT-G precolumn and two SHODEX UT 806M (3x) and SHODEX UT 807 separation columns (Showa Denko Europe GmbH, Konrad-Zuse-Platz 4, 81829 Munich, Germany) connected in series.

[0143] The solvent was vacuum distilled under nitrogen and stabilized with 0.025 wt% 2,6-di-tert-butyl-4-methylphenol. The flow rate used was 1 ml / min, the injection volume was 500 L, and the polymer concentration ranged from 0.01% to <0.05% w / w. Molecular weight calibration was established using monodisperse polystyrene (PS) standards from Polymer Laboratories (now Agilent Technologies, Herrenberger Str. 130, 71034 Boeblingen, Germany) ranging from 580 g / mol up to 11,600,000 g / mol, as well as hexadecane.

[0144] Next, a calibration curve was applied to polyethylene (PE) using the universal calibration method (Benoit H., Rempp P. and Grubisic Z., & in J. Polymer Sci., Phys. Ed., 5, 753 (1967)). The Mark-Houwing parameters used here are PS:k PS =0.000121dl / g, α PS =0.706, PE:k PE =0.000406dl / g, α PE= 0.725 and is valid for a TCB of 135 °C. Data recording, calibration, and calculations were performed using NTGPC_Control_V6.02.03 and NTGPC_V6.4.24 (hsGmbH, Hauptstra 36, ​​D-55437 Ober-Hilbersheim, Germany), respectively. Long Chain Branching Index (LCBI)

[0145] The LCB index is 6 The branching factor g' corresponds to the branching factor g' measured in g / mol. The branching factor g' was measured by gel permeation chromatography (GPC) coupled with multi-angle laser scattering (MALLS), which allows the determination of long-chain branching at high molecular weights. The radius of gyration of each fraction eluted from the GPC was measured by analyzing light scattering at various angles using MALLS (detector: Wyatt Dawn EOS, Wyatt Technology, Santa Barbara, CA) (flow rate: 0.6 ml / min, column packed with 30 M particles, as described above). A 120 mW laser source with a wavelength of 658 nm was used. The relative refractive index was 0.104 ml / g. Data evaluation was performed using Wyatt ASTRA 4.7.3 and CORONA 1.4 software. The LCB index was determined as follows:

[0146] The parameter g' is the ratio of the measured mean square radius of gyration to that of a linear polymer with the same molecular weight. Linear molecules exhibit a g' of 1, while values ​​less than 1 indicate the presence of LCB. The value of g' is a function of moles. The weight M is calculated according to the following formula: g'(M) = <Rg 2 > サンプル,M / <Rg 2 > 線状参照,M

[0147] <Rg 2 >where M is the root mean square of the radius of gyration due to the molar weight M.

[0148] By analyzing the light scattering at different angles, the radius of gyration of each fraction eluted from the GPC is measured (as mentioned above, the flow rate is 0.6 ml / min and the column is packed with 30 μm particles). Therefore, the molar weight M and <Rg 2 > サンプル,M Measured, measured M = 10 6 We can define g' in g / mol. <Rg 2 > 線形参照,M was calculated by establishing the relationship between the radius of gyration and the molecular weight of linear polymers in solution (Zim and Stokemeyer WH 1949) and confirmed by measuring linear PE standards using the same equipment and method as above.

[0149] For the same protocol, see the following documents:

[0150] Zimm BH, Stockmayer WH (1949) Dimensions of chain molecules containing branches and rings. J Chem Phys 17 Rubinstein M., Colby RH. (2003), Polymer Physics, Oxford University Press. Complex shear viscosity η 0.02 (eta(0.02)) and ER When measured at an angular frequency of 0.02 rad / sec and 190°, the results are as follows:

[0151] The samples were melt-pressed at 200 °C and 200 bar for 4 min to produce plates with a thickness of 1 mm. A 25 mm diameter disk was punched and inserted into the rheometer, which was preheated to 190 °C. Measurements can be performed using any commercially available rotational rheometer. In this case, an Anton Paar MCR300 in plate-plate configuration was used. A so-called frequency scan (after annealing the sample at the measurement temperature for 4 min) was performed at T = 190 °C under a constant strain amplitude of 5%. The stress response of the material was measured and analyzed over the excitation frequency range ω from 628 to 0.02 rad / s. The rheological properties, namely the storage modulus G', loss modulus G'', phase lag δ (= arctan(G'' / G')), and complex viscosity η*, were calculated as a function of applied frequency, η*(ω) = [G'(ω) 2 +G''(ω) 2 ] 1 / 2 / ω, calculated using standardized basic software. The latter is η at an applied frequency ω of 0.02 rad / s. 0.02 This becomes:

[0152] ER is determined by the method of R. Shroff and H. Mavridis, "A New Measurement of Polydispersity from Rheological Data of Polymer Melts," J. Applied Polymer Science 57 (1995) 1605 (see also U.S. Pat. No. 5,534,472, column 10, lines 20-30). The calculation method is as follows: ER=(1.781*10 -3 )*G'

[0153] G''=5,000 dyn / cm 2 is the value.

[0154] As those skilled in the art will appreciate, a minimum G'' value of 5,000 dyn / cm 2 For larger values, determining ER involves extrapolation. The calculated ER value then depends on the degree of nonlinearity in the log G' log G' plot. The temperature, plate diameter, and frequency ranges are within the resolution of the rheometer and produce a minimum G'' value of 5000 dyne / cm. 2 is selected to be close to or less than HMWcopo index

[0155] To quantify the crystallization and processability potential of a polymer, the HMWcopo (High Molecular Weight Copolymer) index is used, which is defined as: HMWcopo=(η 0.02 xt maxDSC ) / (10^5)

[0156] This value decreases with increasing ease of processing (low melt viscosity) and the likelihood of rapid crystallization of the polymer. Also, the melt composite shear viscosity η at a frequency of 0.02 rad / s measured as above 0.02 The amount of high molecular weight fraction related to the heat flow maximum time t maxDSC It is also possible to describe and quantify the amount of mixed comonomer that retarded crystallization, as quantified by:

[0157] t maxDSC The DSC temperature is measured under constant temperature isothermal conditions at 124°C using a TA Instruments Q2000 differential scanning calorimeter. Five to six mg of sample is weighed and placed on an aluminum DSC disk. The sample is heated to 200°C at 20 K / min and cooled to the test temperature at 20 K / min to remove the thermal history. The isothermal test is then immediately started, and the time until crystallization occurs is recorded. The vendor software (TA Instruments) is used to calculate the time interval t until the maximum heat flow (peak value) of crystallization. maxDSC The measurement is repeated three times and the average value is calculated in minutes. If no crystallization is observed under these conditions for more than 120 minutes, t maxDSC The HMWcopo index was further calculated using the value = 120 min.

[0158] Melt viscosity η 0.02 Value to t maxDSC The values ​​were multiplied and the product was normalized to a factor of 100000 (10^5). Swell Ratio

[0159] The swell ratios of the polymers of interest were measured at T = 190 °C using a GOTTFERT Rheotester 2000 and Rheograph 25 capillary rheometer equipped with a commercial 30 / 2 / 2 / 20 die (total length 30 mm, effective length = 2 mm, diameter = 2 mm, L / D = 2 / 2, and 20° approach angle) and an optical device (GOTTFERT laser diode) to measure the thickness of the extruded strand. The samples were melted in the capillary barrel at 190 °C for 6 min and then heated for 1440 s. -1 The extrusion is performed at a piston speed corresponding to the die shear rate of 1000 rpm.

[0160] When the piston reaches a position 96 mm from the die entrance, the extrudate is cut at a distance of 150 mm from the die exit (using an automatic cutting device from GOTTFERT). The extrudate diameter is measured as a function of time using a laser diode at a distance of 78 mm from the die exit. The maximum value is D 押出物 The swell ratio was determined according to the following formula: SR=(D 押出 -D ダイ )100% / D ダイ

[0161] where D ダイ is the corresponding diameter of the die exit as measured by the laser diode. Environmental stress cracking resistance by full notch creep test (FNCT)

[0162] The environmental stress crack resistance of polymer samples was measured in aqueous surfactant solutions according to the international standard ISO 16770 (FNCT). Polymer samples were compression-molded into 10 mm thick sheets. Square cross-section bars (10 x 10 x 100 mm) were notched on all four sides perpendicular to the stress direction using a razor blade. Sharp notches 1.6 mm deep were produced using the notching device described by M. Fleissner in Kunststoffe 77 (1987), p. 45.

[0163] The applied load was calculated by dividing the tension by the initial ligament area. The ligament area is the remaining area = total cross-sectional area of ​​the specimen minus the notch area. For FNCT specimens: 10x10 mm 2 - 4 times the trapezoidal notch area = 46.24 mm 2 (Remaining cross section for fracture process / crack propagation). The specimens were loaded with a constant load of 6 MPa at 50°C in a 2% (by weight) aqueous solution of the non-ionic surfactant ARKOPAL N100, under the standard conditions suggested by ISO 16770. The time until the specimens failed was determined. Weight Swell and Diameter Swell (Uniloy Test)

[0164] Weight swell and diameter swell measurements were performed using a Uniloy regression blow molding machine model 5630 using a 1 gallon center-weighted bottle mold with an approximate parison drop time of 1.1 seconds, simulating industrial process conditions.

[0165] Gravimetric swelling was measured by adjusting the bottle weight to the desired amount of 90 g with the reference resin Petrothene LR732002 and then comparing the weight of a bottle of the resin under investigation produced under the same machine parameters.

[0166] The test bottle is shown in FIG.

[0167] Thus, the weight swell is given by: W B -90 In the formula, W B is the weight of the bottle tested in grams.

[0168] The diameter swell was measured by measuring the length of the bottle burr from the top (including the protruding top burr) to the bottom and along the bottle handle using the scale marks on the bottle weight, which was the same as the reference resin. The mold relative to the parison was adjusted so that the top burr edge of the reference resin was within the 9 cm mark on the handle.

[0169] The machine parameters were as follows: Prime mover load / AMP.-Approx. 40amps; Screw speed - about 370 rpm (adjust to adjust the tail length of the parison); Hydraulic oil temperature -27~32℃ (80~90°F); Mold cooling temperature - inlet 4°C (39°F), outlet 8°C (47°F); Shot pressure - 7MPa (1050psi); Head pressure -14MPa (2000psi); Parison fall time - about 1.1 seconds; Total cycle time - approximately 15.30 seconds; Heating Zone: Feed - 330°F; Transition -177°C (350°F); Measurement 1 - 190°C (375°F); Measurement 2 - 190°C (375°F); Adapter - 190°C (375°F); Die - 190°C (375°F); timer: Delay before blow - 0.0 seconds; Clamp pause - 0.0 seconds; Charge delay -0.0 seconds; Blow delay - 0.45 seconds; Blow time - 10.0 seconds; Exhaust time - 2.0 seconds; Shot delay -0.0 seconds.

[0170] The reference resin, Petrothene LR732002, is a Cr-catalyzed ethylene polymer with an FNCT of about 0.4 seconds at 6 MPa / 50° C., measured as described above.

[0171] Other features of Petrothene LR732002 include: Density: 0.953g / cm 3 ; MIF:36g / 10min; MIF / MIE:100; ER: 5.4.

[0172] In these examples, diameter swelling was considered satisfactory when it fell within the range of 8-10 cm. Cast Film Measurement

[0173] Gel film measurements were performed on an OCS extruder, model ME 202008-V3, with a screw diameter of 20 mm, screw length of 25D, and slit die width of 150 mm. The casting line was equipped with a chill roll and winder (model OCS CR-9). The optical equipment included an OSC film surface analyzer camera, model FTA-100 (flash camera system), with a resolution of 26 m x 26 m. The resin was first purged for 1 hour to stabilize the extrusion conditions, after which inspection and recording were performed for 30 minutes. The resin was extruded at 220 °C with a take-up speed of approximately 2.7 m / min to produce a 50 μm thick film. The cold rolling temperature was 70 °C.

[0174] As shown in Tables 1 to 3, the above-mentioned inspection was performed using a surface analysis camera, and the total gel content and the content of gels with a diameter of more than 450 μm were obtained. Comonomer Content

[0175] The comonomer content is measured by IR according to ASTM D624898 using a Bruker FT-IR spectrometer, Tensor 27, calibrated with a stoichiometric model to measure the butyl side chains of hexene in PE. The results were compared with the estimated comonomer content obtained from the mass balance of the polymerization process and were found to be in agreement. -Process Settings

[0176] The polymerization process was carried out under continuous conditions in a plant consisting of two gas phase reactors connected in series as shown in the drawing.

[0177] The polymerization catalyst was prepared as follows. Preparation of spherical catalyst supports

[0178] A magnesium chloride and alcohol adduct containing approximately 3 moles of alcohol was prepared according to the method described in Example 2 of US Pat. No. 4,399,054, but operated at a speed of 2000 RPM instead of 10,000 RPM.

[0179] The adduct thus obtained was dealcoholized by heat treatment under a nitrogen flow over a temperature range of 50-150°C up to an alcohol content of up to 25 wt%. Preparation of solid catalyst component

[0180] 1 L of TiCl4 was introduced into a nitrogen-purged 2 L four-neck round-bottom flask at 0 °C. Then, 70 g of the spherical MgCl2 / EtOH adduct thus prepared, containing 25 wt. % ethanol, was added with stirring at the same temperature. The temperature was increased to 130 °C within 3 h and maintained at that temperature for 60 min. The stirring was then stopped, the solid was allowed to settle, and the supernatant was siphoned off. Fresh TiCl4 was added up to a total volume of 1 L, and the treatment at 130 °C was repeated for 60 min. After settling and suction, the solid residue was washed five times with hexane at 50 °C and twice with hexane at 25 °C and then dried under vacuum at 30 °C.

[0181] A 2-L four-neck glass reactor equipped with a stirrer was charged with 812 cc of hexane at 10°C. While stirring, 50 g of the catalyst component prepared above was introduced at 10°C. While maintaining a constant internal temperature, 15 g of tri-n-octylaluminum (TNOA) in hexane (approximately 80 g / L) and a certain amount of cyclohexylmethyl-dimethoxysilane (CMMS) (so that the TNOA / CMMS molar ratio was 50) were slowly introduced into the reactor, and the temperature was maintained at 10°C. After stirring for 10 minutes, a total of 65 g of propylene was introduced into the reactor at a constant rate for 6.5 hours at the same temperature. The entire contents were then filtered and washed three times with hexane (100 g / L) at 30°C. After drying, the resulting prepolymerized catalyst (A) was analyzed and found to contain 55 wt.% polypropylene, 2.0 wt.% Ti, 9.85 wt.% Mg, and 0.31 wt.% Al.

[0182] About 100 g of the solid prepolymerized catalyst thus prepared was placed in a nitrogen gas purged glass reactor and slurried with 1.0 L of heptane at 50°C.

[0183] Next, ethyl acetate (EAA) and tetrahydrofuran (CE) were carefully added dropwise in amounts such that the molar ratio of Mg / EAA was 4 and the molar ratio of Mg to CE was 4 (60 min).

[0184] The slurry was stirred for 1.5 hours while maintaining the internal temperature at 50°C. Then, the stirring was stopped, the solids were allowed to settle, and the supernatant liquid was siphoned off. The solids were washed in one portion with anhydrous heptane at 50°C, with stirring, to a volume of up to 1 L. Then, the stirring was stopped, the solids were allowed to settle, and the supernatant liquid was siphoned off. The volume was then adjusted back to 1 L with anhydrous heptane, and the temperature was increased to 85°C and maintained with stirring for 2 hours. Then, the stirring was stopped, the solids were allowed to settle, and the supernatant liquid was siphoned off.

[0185] The solid was washed three times with anhydrous hexane (3 x 1000 mL) at 25°C, collected, dried under vacuum and analyzed, which revealed that the resulting EAA / CE molar ratio was 0.93. Example 1 - See

[0186] As shown in the drawing, polyethylene was produced in a series of fluidized bed reactors and a multi-zone circulating reactor with two interconnected reaction zones.

[0187] To carry out the polymerization, 11.6 g / h of the above-described solid catalyst was added to the first stirred pre-contact vessel using 0.70 kg / h of liquid propane, and a mixture of triisobutylaluminum (TIBA) and diethylaluminum chloride (DEAC) was also added. The weight ratio of tributylaluminum to diethylaluminum chloride was 7:1. The alkyl to solid catalyst ratio was 5:1. The first pre-contact vessel was maintained at 50°C with an average residence time of 35 minutes. The catalyst suspension from the first pre-contact vessel was continuously transferred to the second stirred pre-contact vessel, which was also operated with an average residence time of 35 minutes and maintained at 50°C. The catalyst suspension was then continuously transferred to a fluidized bed reactor (FBR) (1) via line (2).

[0188] In the fluidized-bed reactor (1), ethylene was polymerized in the presence of propane as an inert diluent using hydrogen as a molecular weight regulator. 47.5 kg / h of ethylene, 158 g / h of hydrogen, and 11 kg / h of propane were fed to the fluidized-bed reactor (1) via line 3. No comonomer was added. The polymerization was carried out at a temperature of 80°C and a pressure of 3.0 MPa. The selected feed rates resulted in an ethylene concentration of 10.9% by volume in the reactor and a hydrogen / ethylene molar ratio of 2.6 in the reactor.

[0189] The polyethylene obtained in the fluidized bed reactor (1) had an MIE of 74 g / 10 min and a density of 0.967 g / cm 3 It was.

[0190] The polyethylene obtained in the fluidized-bed reactor (1) was continuously transferred to a multi-zone circulation reactor (MZCR) operated at a pressure of 2.6 MPa and a temperature of 85°C, measured at the reactor gas outlet. The riser (4) had an internal diameter of 200 mm and a length of 19 m. The downcomer (5) had a total length of 18 m, with the upper half divided into 5 m sections with an internal diameter of 300 mm and the lower half divided into 13 m sections with an internal diameter of 150 mm. To broaden the molecular weight distribution of the final ethylene polymer, the second reactor was operated under different monomer and hydrogen concentration conditions in the riser (4) and the riser (5). This was achieved by feeding a 330 kg / h liquid stream (liquid barrier) via line (7) to the top of the downcomer (5). The liquid stream in line 19 came from the condensation step in condenser 6, operating at 54°C and 2.6 MPa, where a portion of the recycle stream was cooled and partially condensed. As shown in the figure, the pump is positioned downstream of the condenser 6 .

[0191] Monomers were fed to the downcomer at three points. At input point 1 (8), 25 kg / h of liquid condensate (10), 9 kg / h of ethylene (9), and 380 g / h of 1-hexene (9) were introduced. At input point 2 (11), 15 kg / h of liquid condensate (13) and 4.5 kg / h of ethylene (12) were introduced. At input point 3 (14), 15 kg / h of liquid condensate (16) and 4.5 kg / h of ethylene (15) were introduced. 5 kg / h of propane, 28.3 kg / h of ethylene, and 30 g / h of hydrogen were fed to the recycle system via line 19.

[0192] The final polymer was discharged discontinuously via line 18.

[0193] The first reactor produced approximately 50 wt % (split wt %) of the total amount of final polyethylene resin produced by the first and second reactors.

[0194] The final MIF of the resulting precursor polyethylene composition (I) was 30.6 / 10 min. The resulting density was 0.956 g / cm.

[0195] The amount of comonomer (hexene-1) was about 0.40 wt%.

[0196] A portion of the resulting polymer powder (polymerized, i.e. without additives) was finally extruded in a Kobe mixer LCM80, adding the following additives: -1000 ppm calcium stearate; -800 ppm Irganox 1010; and -1600 ppm Irgafos 168 (all ppmw).

[0197] Irganox 1010® is 2,2-bis[3-[,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl)-1-oxopropoxy]methyl]-1,3-propanediyl-3,5-bis(1,1-dimethylethyl)-4-hydroxybenzenepropionate supplied by BASF SE, Ludwigshafen, Germany.

[0198] Irgafos 168® is tris(2,4-di-tert-butylphenyl) phosphite sold by Ciba Geigy.

[0199] The polymer powder and the additives were introduced into the mixer inlet at a rate of 170 kg / h and a screw speed of 800 rpm. Between the two mixing zones, a throttle gate was located, which was adjusted to a temperature of 220°C in front of the gate. A gear pump was located beyond the second mixing zone and was set to a suction pressure of 0.1 MPa (1.0 bar).

[0200] The polymerization conditions and polymer data (after extrusion) are reported in Table 1. Example 2

[0201] A portion of the polymer powder of Example 1 (polymerized) was extruded with 1000 ppm calcium stearate, 800 ppm Irganox 1010, 1600 ppm Irgafos 168, and 267 ppm Pergaprop 7.5PP (all ppmw).

[0202] The polymer data are reported in Table 1.

[0203] Pergaprop 7.5 PP® is a 7.5 wt% mixture of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and polypropylene supplied by PERGAN GmbH, Bocholt, Germany.

[0204] The same extrusion equipment and conditions as in Example 1 were used. Example 3 - See

[0205] To carry out the polymerization, the conditions were kept the same according to Example 1, except that a downcomer was introduced.

[0206] Monomers were fed to the downcomer at three points. At input point 1 (8), 25 kg / h of liquid condensate (10), 9 kg / h of ethylene (9), and 330 g / h of 1-hexene (9) were introduced. At input point 2 (11), 15 kg / h of liquid condensate (13) and 4.5 kg / h of ethylene (12) were introduced. At input point 3 (14), 15 kg / h of liquid condensate (16) and 4.5 kg / h of ethylene (15) were introduced. 5 kg / h of propane, 27.4 kg / h of ethylene, and 30 g / h of hydrogen were fed to the recycle system via line 19.

[0207] The final polymer was discharged discontinuously via line 18.

[0208] The first reactor produced approximately 50.5 wt % (split wt %) of the total amount of final polyethylene resin produced by the first and second reactors.

[0209] The resulting precursor polyethylene composition (I) had a final MIF of 36.2 / 10 min and a density of 0.957 g / cm. Amount of comonomer (hexene-1)

[0210] A portion of the resulting polymer powder (polymerized, ie, without additives) was extruded with 100 ppm calcium stearate, 800 ppm Irganox 1010, and 1600 ppm Irgafos 168 (all ppmw).

[0211] The same extrusion equipment and conditions as in Example 1 were used.

[0212] The polymerization conditions and polymer data (after extrusion) are reported in Table 1. Example 4

[0213] A portion of the polymer powder of Example 3 (polymerized) was extruded with 100 ppm calcium stearate, 800 ppm Irganox 1010, 1600 ppm Irgafos 168, and 267 ppm Pergaprop 7.5PP (all ppmw).

[0214] The same extrusion equipment and conditions as in Example 1 were used.

[0215] The polymer data are reported in Table 1. Table 1 [Table 1]

[0216] Note: C2H4 = ethylene; C6H 12 = hexene; *2% Arkopal N100 in water

Claims

1. 1. A polyethylene composition comprising: 1) the MIF / MIE ratio is 60 to 125, preferably 62 to 123, where MIF is the melt flow index at 190°C under a load of 21.60 kg, and MIE is the melt flow index at 190°C under a load of 2.16 kg, both determined in accordance with ISO 1133-2:2011; 2) MIF is 15 to 40 g / 10 min, preferably 20 to 35 g / 10 min, or 25 to 40 g / 10 min, particularly 25 to 35 g / 10 min; 3) Density is 0.955 to 0.965 g / cm ３ , particularly 0.956 to 0.960 g / cm ３ and measured at 23°C according to ISO 1183-1:2012; 4) The ER value is 3.0 to 5.5, or 3.5 to 5.5, preferably 3.0 to 5.2, or 3.5 to 5.2, more preferably 4.0 to 5.0, or 3.5 to 4.8, and most preferably 4.2 to 5.2, or 4.2 to 4.8; 5) η ０．０２ is 150,000 Pa s or less, preferably 100,000 Pa s or less, more preferably 80,000 Pa s or less, in particular 150,000 to 25,000 Pa s, or 100,000 to 25,000 Pa s, or 80,000 to 25,000 Pa s or less; where η ０．０２ is measured in a parallel plate (or so-called plate-plate) rheometer under dynamic oscillatory shear mode at an applied angular frequency of 0.02 rad / s. ℃ is the complex viscosity of the melt measured at a temperature ER is calculated as follows: ER=(1.781*10 －３ )*G' where G''=5,000 dyn / cm ２ The value of where: G' = storage modulus, G'' = loss modulus; The polyethylene composition, wherein G' and G'' are both measured by dynamic oscillatory shear in a plate-plate rotational rheometer at a temperature of 190°C.

2. The polyethylene composition has a MIF / MIE of less than 1), preferably 50 to 119, more preferably 60 to 110. Ｉ ) with a radical initiator, wherein the MIF / MIE of the final polyethylene composition (after contact with said radical initiator) is 1) and the MIF / MIE of said precursor polyethylene composition (I) is 1) Ｉ ) and the ratio 1) / 1 Ｉ 2. The polyethylene composition according to claim 1, wherein σ is 1.05 or more, in particular 1.05 to 1.8, or 1.05 to 1.

5.

3. The precursor polyethylene composition (I) is 2 Ｉ ) MIF is 20 to 50 g / 10 min, preferably 25 to 45 g / 10 min; 3 Ｉ ) density is 0.955 g / cm ３ More than 0.965 g / cm3 or less, particularly 0.956 to 0.960 g / cm ３ That is, 4 Ｉ ) the ER value is 2 to 4, preferably 2 to 3.5; 5 Ｉ )η ０．０２ 3. The polyethylene composition according to claim 2, having the additional feature that the viscosity is at most 150,000 Pa s, preferably at most 100,000 Pa s, more preferably at most 80,000 Pa s, especially at most 150,000 to 15,000 Pa s, or at most 100,000 to 21,000 Pa s, or at most 80,000 to 15,000 Pa s.

4. The precursor polyethylene composition (I) is A) 30 to 70% by weight, preferably 40 to 60% by weight, of an ethylene homopolymer or copolymer (homopolymer is preferred) having a density of 0.960 g / cm ３ or more, and according to ISO 1333, the melt flow index MIE at 190°C under a load of 2.16 kg is 8 g / 10 min or more, preferably 40 g / 10 min or more; 3. The polyethylene composition according to claim 2, comprising: B) 30 to 70 wt. %, preferably 40 to 60 wt. % of an ethylene copolymer having an MIE value less than that of A), preferably less than 0.5 g / 10 min.

5. 2. The polyethylene composition according to claim 1, obtained by using a Ziegler-Natta polymerization catalyst in said polymerization stage.

6. The Ziegler-Natta polymerization catalyst A) Ti, Mg, chlorine, and one internal electron donor ED selected from esters of aliphatic monocarboxylic acids (EAA) and another internal donor ED selected from cyclic ethers (CE). Ｉ in an amount such that the EAA / CE molar ratio is from 0.02 to less than 20; B) an organoaluminum compound, and optionally C) an external electron donor compound.

7. 10. The polyethylene composition of claim 1, consisting of or comprising one or more ethylene copolymers.

8. The polyethylene composition is a swell ratio greater than 140%, in particular between 140% and 190%; FNCT 6 MPa / 50°C for 10 hours or more, preferably 15 hours or more, in particular from 10 or 15 hours to 50 hours; the comonomer content is less than or equal to 1.5% by weight, in particular between 0.1 and 1.5% by weight, relative to the total weight of the composition; - MIP is at least 0.3 g / 10 min, more preferably at least 0.5 g / 10 min, in particular between 0.3 and 4 g / 10 min, or between 0.5 and 4 g / 10 min, where MIP is the melt flow index measured according to ISO 1133-1 2012-03 at 190°C under a load of 5 kg; - a (MIF / MIE)ER ratio between MIF / MIE and ER of less than or equal to 28, in particular 28-15 or 28-18; a long chain branching index LCBI of not more than 0.55, more preferably not more than 0.62, the upper limit being preferably 0.95 in each case; where LCBI is the ratio of the measured mean square radius of gyration Rg to the mean square radius of gyration for linear PE of the same molecular weight at a molar weight of 1,000,000 g / mol, as measured by GPC-MALLS; -η ０．０２ is 35,000 Pa s or more, more preferably 40,000 Pa s or more, especially 35,000 or 40,000 to 70,000 Pa s; -ratio (η ０．０２ / 1000) / LCBI, i.e., η ０．０２ the value between the value obtained by dividing by 1000 and the LCBI is 50 to 100, more preferably 65 to 95; an HMWcopo index of 0.5 to 5, in particular 0.5 to 3.5, wherein the HMWcopo index is determined according to the following formula: HMWcopo = (η ０．０２ x t ｍａｘＤＳＣ ) / (10^5) Here, t ｍａｘＤＳＣ is the time required to reach the heat flow maximum of crystallization (in mW) (time to reach the maximum crystallization rate, equivalent to t½ crystalline half-life) measured by differential scanning calorimetry (DSC) in isothermal mode at a temperature of 124°C under quiescent conditions, expressed in minutes.

9. The process is carried out in a manner that the MIF / MIE is less than the MIF / MIE 1), preferably between 50 and 119, more preferably between 60 and 110. Ｉ ) with a radical initiator, wherein the MIF / MIE ratio of the final polyethylene composition (after contact with said radical initiator) is 1) and the MIF / MIE ratio of said precursor polyethylene composition (I) is 1) Ｉ ) and the ratio 1) / 1 Ｉ 2. The process for preparing a polyethylene composition according to claim 1, wherein σ is 1.05 or more, in particular 1.05 to 1.8, or 1.05 to 1.

5.

10. The precursor polyethylene composition (I) is 2 Ｉ ) MIF is 20 to 50 g / 10 min, preferably 25 to 45 g / 10 min; 3 Ｉ ) density is 0.955 g / cm ３ More than 0.965 g / cm3 or less, particularly 0.956 to 0.960 g / cm ３ That is, 4 Ｉ ) the ER value is 2 to 4, preferably 2 to 3.5; 5 Ｉ )η ０．０２ is equal to or less than 150,000 Pa s, preferably equal to or less than 100,000 Pa s, more preferably equal to or less than 80,000 Pa s, especially equal to or less than 150,000 to 15,000 Pa s, or equal to or less than 100,000 to 21,000 Pa s, or equal to or less than 80,000 to 15,000 Pa s.

11. 10. The process of claim 9, carried out by contacting the radical initiator with the precursor polyethylene composition (I) in an extrusion apparatus at a temperature of from 180 to 350°C.

12. 10. The process of claim 9, wherein the radical initiator is selected from organic peroxides.

13. 13. The process of claim 12, wherein the amount of organic peroxide or peroxide added corresponds to a content of initiator in the precursor polyethylene composition (I) of 10 to 100 ppmw, more preferably 15 to 90 ppmw, especially 15 to 80 ppmw, or 15 to 50 ppmw.

14. 13. The process of claim 12, wherein the organic peroxide or peroxide is selected from 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 3,6,9-triethyl-3,6,9-trimethyl-1,2,4,5,7,8-hexane, or typically 3,6,9-trimethyl-3,6,9-tris(alkyl)-1,2,4,5,7,8-hexane, where alkyl is propyl or ethyl.

15. 10. An article of manufacture comprising the polyethylene composition of claim 1.

16. 16. An article of manufacture according to claim 15 in the form of a blow-molded article, in particular handleware.

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