Multimodal polyethylene polymers and process preparing said polymer

SUMMARY OF THE INVENTION

The present invention as perceived in the first aspect describes a polyethylene with multimodal distribution of molecular masses, consisting of:

(i) 20-70% by weight of a low molecular weight homopolymer of ethylene;

(ii) 20-70% by weight of the first higher molecular weight ethylene copolymer;

and (iii) 0.5-9.5% by weight of the second higher molecular weight ethylene copolymer, wherein said second ethylene copolymer has a higher average molecular weight than said first higher molecular weight ethylene copolymer.

Polyethylene with a multimodal composition is preferred.

From the standpoint of a further aspect, the invention also comprises a process for preparing the above-described polyethylene, which consists of polymerizing ethylene and, as desired, at least one other α-olefin to obtain such polyethylene, and the above-mentioned polymerization takes place in a minimum of three steps.

Another aspect of the present invention is the polyethylene obtained in the process described above.

Another aspect of the present invention is the above-described composition (composition) of polyethylene.

Another aspect of the present invention is an object made from the above-defined polyethylene or its above-described composition.

- EP 2809717

In a preferred embodiment, the object is a pipe.

A further aspect of the present invention is the process of preparing the above-mentioned object, which consists of forming, e.g. blowing into the mold of the above-described polyethylene or its composition, in the pipe production process.

Another aspect of the present invention is the use of the above-described polyethylene or its pipe-making composition.

DETAILED DESCRIPTION OF THE INVENTION

definitions

As used herein, the term "polyethylene" refers to a polymer that consists of repeating fragments of ethylene derivatives. The homopolymers may, for example, comprise at least 99%, preferably not less than 99.5%, more preferably not less than 99.9%, and preferably not less than 99.95%, e.g. 100% by weight of the repeating units derived from ethylene.

As used herein, the term "ethylene copolymer" means a polymer consisting of repeating parts derived from ethylene and at least one other monomer. In typical copolymers, at least 0.05%, more preferably at least 0.1%, and even better at least 0.4% by weight of the repeating molecules is derived from at least another monomer other than ethylene. In the case of typical ethylene copolymers, they usually do not consist of more than 15% by weight of repeating molecules derived from monomers other than ethylene

As used herein, the term "mass" means relative to the mass of polyethylene unless expressly stated otherwise.

The terms "lower" and "higher" used here are used relativly. Thus, the lower molecular weight ethylene polymer has a lower molecular weight than the higher molecular weight polymer.

As used herein, the term LMW polymer refers to an ethylene polymer having a lower molecular weight.

As used herein, the term HMW1 polymer refers to the first higher molecular weight ethylene comonomer. As used herein, the term HMW2 refers to a secondary (second) high molecular weight ethylene copolymer. Both HMW1 and HMW2 have molecular weights higher than the LMW polymer. HMW2 has a molecular weight higher than HMW1. For this reason, the invented polyethylene is trimodal.

Wherever the term "molecular weight" is used, it means the average molecular weight unless otherwise indicated.

The term "multimodal" as used herein refers to a polymer consisting of multiple components or fractions that have been produced under different polymerization conditions and / or using different catalyst systems (i.e., in a system using more than one active element) in one process or step, or also with the use of two or more catalysts at the polymerization stage or else in a step resulting in different molecular weight and molecular weight distribution of the components and / or different comonomer contents. The "multi" prefix refers to the various components contained in the polymer. For example, a polymer consisting of three components is "trimodal".

The term "multimodal composition" as used herein refers to the composition in the form of multiple components or fractions, each with a different composition. In a preferred embodiment, the components or

The fractions have each other composition. Thus, for example, the ethylene homopolymer composition, an ethylene copolymer containing 0.1% by weight comonomer and an ethylene copolymer containing 0.5% by weight comonomer is a multimodal composition, more specifically a trimodal composition.

The term "multimodal molecular weight distribution" as used herein refers to the form of the molecular weight distribution curve, i.e. the graph view of the mass fraction of the polymer as a function of the molecular weight. Multimodal molecular weight distribution polyethylene exhibits two or more maxima, or at least distinct increases in comparison with the curves of individual components. In addition, multimodality can mean differences in the melting or crystallization curves of components. Thus, a polymer consisting of one component produced under continuous polymerization conditions would be called unimodal here.

The term catalyst system as used herein refers to all active elements that catalyze the polymerization reaction. A typical catalyst system is a coordinated drainage system consisting of a transition metal (active precursor) and activator (sometimes called co-catalyst) capable of activating the transition of the metal compound.

The term "Ziegler Natta (ZN) catalyst" as used herein refers to a catalyst consisting preferably of a component comprising a transition metal (e.g., Ti) linked by a sigma bond to ligands and an activator (e.g., an Al organometallic compound). The preferred Ziegler Natta catalysts also optionally contain a building material molecule.

The term "suspension polymerization" as used herein refers to a polymerization in which the polymer is formed as a solid in a liquid. The liquid may be a polymer monomer. In the latter case, the polymerization is also called holistic. The term suspension polymerization also includes what is sometimes referred to as supercritical polymerization, i.e.n. polimeryzacjin which the polymer is a solid suspended in a liquid quite close to its critical point, and in the case where the liquid is a mixture, its pseudocritical point. The liquid can be considered quite close to its critical point if the compressibility factor is less than twice its critical compressibility factor, or in the case of a mixture, its pseudocritical factor.

The term "multi-stage polymerization" as used herein refers to polymerization carried out in two or more stages. In general, each stage is carried out in a separate reactor. The term multi-stage polymerization is used interchangeably with the term multi-step polymerization.

Polyethylene

The final polyethylene for processing into products (e.g., pipes) will often contain additives, such as carbon black and dyes, as described below, which are usually added to the polyethylene in the collecting batches after completion of polyethylene synthesis. The following details relating to polyethylene refer to polyethylene as such and do not contain any further additives, unless expressly stated otherwise.

The polyethylene of the present invention is multimodal. This polyethylene has a multimodal (e.g., trimodal) molecular weight distribution. In a preferred embodiment, the polyethylene has a multimodal composition (e.g., trimodal).

- EP 2809717

The total ethylene monomer content of the polyethylene according to the present invention is 50-99.9% more, 50-99.5% more, and even 75-99.0% more, e.g. 85 to 97% by weight. The content of ethylene monomer in the range of 92-99.8% by weight and even more 98 to 99.9% by weight is extremely preferred.

The total comonomer content of the polyethylene according to the present invention is in the preferred embodiment 0.1-10% by weight, even better 0.2-5% by weight and still a bit better 0.3

- 3% by weight. When it is stated herein that the content of a given monomer in a polymer is defined, it should be understood that the monomer is present in the polymer in the form of a repeating particle. A skilled person can easily determine what is a repeating molecule for any given monomer. The comonomer is in the preferred version one or more (e.g. one) αolefin. The choice of comonomer from propylene, 1-butene, 1-pentene, 1-hexene, 1-octene and mixtures thereof is particularly preferred. However, the preferred α-olefin is 1-butene.

The polyethylene shown in the invention is preferably high density polyethylene (HDPE). HDPE has the advantage that at relatively low dead weight it is characterized by high mechanical resistance, resistance to corrosion and chemicals and long-term stability. In a preferred embodiment, the polyethylene of the present invention has a density of 935-910 kg / m³and better 935-970 kg / m³even better 940-965 kg / m³ and still a lot better 945-962 kg / m³.

The polyethylene shown in the present invention is preferably one that has an MFR5 in the amount of 0.05-2.0, more preferably 0.05-1.0, even better 0.1 to 0.75, and still much better 0.15 to 0.6 g / 10min. This is a range suitable for use in pipes, i.e. providing the possibility of molding polyethylene by extrusion under pressure.

The polyethylene shown in the invention is preferably one that has FRR (MFR5 / MFR2) in the amount of 2.6-10, preferably 2.9-8, and even better 3-6.

The polyethylene shown in the invention is preferably one that has a melting point of 100-140 ° C, more preferably 110-138 ° C, and even better 120-135 ° C.

The Mn (number average molecular weight) of the polyethylene presented in the invention is 1,000,000 to 1,000,000 g / mole, more preferably 3,000-40,000 g / mole, and even better 5,000-30,000 g / mole. The average molecular weight (Mw) is 100,000-1.000.000 g / mol, and more preferably 150,000-750,000 g / mol, and even better 200,000-500,000 g / mol.

The polyethylene presented in the invention is multimodal. In a preferred embodiment, the polyethylene of the invention is trimodal. The preferred molecular weight distribution in polyethylene (Mw / Mn) is 5-100, and even better 10-50.

The multimodality and broad molecular weight distribution of the polyethylene shown in the invention provides an attractive balance of achievable polymer properties. In particular, the presence of a small admixture, e.g. 0.5-9.5% by weight of a second high molecular weight ethylene copolymer, and in particular a very high molecular weight copolymer, offers a polyethylene with excellent SCG strength, while at the same time high resistance to RCP, scratches and hardness .

The polymer with lower molecular weight

The lower molecular weight polymer contained in the polyethylene described in the present invention is an ethylene homopolymer.

In a preferred embodiment, the lower molecular weight ethylene homopolymer has a density of 920-980 kg / m³ and preferably 920-970 kg / m³. In some cases, the preferred density of the lower molecular weight homopolymer ethylene is 930-965 kg / m³ or better 940-960

- 8 - EP 2809717 kg / m³. However, it is best if the density of the lower molecular weight homopolymer ethylene is 960-975 kg / m³ , more specifically 967-972 kg / m³.

The preferred MFR2 of the lower molecular weight ethylene homopolymer is 10-5000 g / 10min, preferably 20-2000g / 10min, and even better 50-1500g / 10min.

The preferred FRR (MFR5 / MFR2) of the lower molecular weight ethylene homopolymer is 2.6-10, preferably 2.9-8, and even better 3-6.

The preferred melting point of the lower molecular weight homopolymer of ethylene is 120-140 ° C; and more preferably 125-138 ° C, and even better 127-135 ° C.

The Mn of the lower molecular weight ethylene homopolymer is 1,000-100,000 g / mol, more preferably 1,500-80,000 g / mol, and even better 2,000-60,000 g / mol, e.g., 2,500-5000 g / mol. The average molecular weight (Mw) of the lower molecular weight ethylene homopolymer is 5,000-150,000 g / mol, more preferably 10,000-100,000 g / mol, and even better 15,000-80,000 g / mol, e.g. 17,000-35000 g / mol.

The Mw / Mn of the lower molecular weight ethylene homopolymer is in the preferred embodiment 3-18, preferably 4-15, and still better 5-13.

The preferred amount of the lower molecular weight ethylene homopolymer contained in the polyethylene of the present invention is 30-70 wt%, more preferably 35-65 wt%, even better 40-60 wt%, and even more preferred 45-55 wt%, based on for a mass of polyethylene.

In a preferred embodiment, the lower molecular weight ethylene homopolymer is a Ziegler Nata polymer, i.e. it has been prepared in the polymerization of kata.lizowanej Ziegler Natta.

Pierwszy polimer o wyższej masie cząsteczkowej

Pierwszy polimer o wyższej masie cząsteczkowej zawarty w polietylenie niniejszego wynalazku to kopolimer etylenu. Preferowane kopolimery składają się z jednego lub więcej (np.

jednego) komonomeru α-olefin. Preferowaną α-olefinę komonomeru wybiera się z pośród propylenu, 1-butenu, 1-pentenu, 4-metyl-1-pentenu, 1-heksenu, 1-oktenu i ich mieszanin. W preferowanym wykonaniu komonomer jest 1-butenem, tzn. pierwszy polimer o wyższej masie cząsteczkowej jest kopolimerem 1-butenu.

Ilość monomeru etylenu zawarta w pierwszym polimerze o wyższej masie cząsteczkowej to 50 do 99.9% masy, a lepiej 50-99.5% masy. W niektórych pierwszych polimerach o wyższej masie cząsteczkowej preferowana zawartość monomeru etylenu to 75-99.0 % wagowo, np. 85 do 97 % masy kopolimeru. W bardziej preferowanych wykonaniach pierwszego polimeru o wyższej masie cząsteczkowej zawartość monomeru etylenu wynosi 90-99.8 % wagowo, a lepiej 98 do 99.7 % masy kopolimeru. The total comonomer content in the first polymer of higher molecular weight is in the preferred embodiment 0.1-9.5% by weight, preferably 0.2-4.5% by weight, and even better 0.3-2.5% by weight of the copolymer. The preferred comonomer content (based on weight%) in the first polymer of higher molecular weight is more than 200%, more preferably more than 400%, and even better by over 900% higher than in the lower molecular weight copolymer.

In a preferred embodiment, the first higher molecular weight ethylene copolymer has a density of 880-960 kg / m³ and better 880-940 kg / m³. In some embodiments, the first higher molecular weight ethylene copolymer has a density of 890-930 kg / m³ and even better 890-920 kg / m³. However, it is best if the first higher molecular weight ethylene copolymer has a density of 920-955 kg / m³ and even better 930-950 kg / m³.

- EP 2809717

The preferred MFR21 of the first higher molecular weight ethylene copolymer is 0.1-10 g / 10min, more preferably MFR21 is 0.2-5g / 10min, and more preferably MFR21 is 0.3-4g / 10min.

The preferred FRR (MFR5 / MFR2) of the first higher molecular weight ethylene copolymer is 2.6-10, preferably 2.8-8, and even better 3-6.

The Mn of the first higher molecular weight ethylene copolymer is 10.000150,000 g / mol, more preferably 20,000-125,000 g / mol, and even better 30,000-100,000 g / mol.

The average molecular weight (Mw) of the first higher molecular weight ethylene copolymer is higher than the Mw of the lower molecular weight ethylene homopolymer. In a preferred embodiment, the average molecular weight (Mw) of the first higher molecular weight ethylene copolymer is higher by 100%, more preferably by more than 200% and even better by over 400% higher than the Mw of the lower molecular weight ethylene homopolymer. Masscząsteczkowa (Mw) pierwszego kopolimeru etylenu o wyższej masie cząsteczkowej w preferowanym wykonaniu to 100.000-1.000.000 g/mol, a lepiej 150.000-800.000 g/mol, a jeszcze lepiej 200.000-700.000 g/mol.

Preferowany Mw/Mn pierwszego kopolimeru etylenu o wyższej masie cząsteczkowej to 3-25, a lepiej 4-20, a jeszcze lepiej 5-18.

Preferowana ilość pierwszego kopolimeru etylenu o wyższej masie cząsteczkowej zawartego w polietylenie stanowiącym niniejszy wynalazek to 30-70 % wagowo, a lepiej 35-65 % wagowo, a jeszcze lepiej 40-60 % wagowo, a jeszcze bardziej preferowana 40-50 % wagowo, w oparciu o masę polietylenu.

W preferowanym wykonaniu pierwszy kopolimer etylenu o wyższej masie cząsteczkowej jest polimerem Ziegler Nata, tj. wytworzony został w polimeryzacji katalizowanej Ziegler Natta.

Drugi kopolimer o wyższej masie cząsteczkowej

Drugi polimer o wyższej masie cząsteczkowej zawarty w polietylenie niniejszego wynalazku to kopolimer etylenu. Preferowane polimery skthey load from one or more (e.g.

one) α-olefin comonomer. The preferred comonomer α-olefin is selected from propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene and mixtures thereof. In a preferred embodiment, the comonomer is 1-butene, i.e. the second polymer of higher molecular weight is a 1-butene copolymer.

The amount of ethylene monomer contained in the second polymer with a higher molecular weight is up to 99.9% by weight, and more preferably 50-99.5% by mass, and even better 75-99.0% by weight, e.g. 85 to 97% by weight of the copolymer. The combined comonomer content in the second polymer of higher molecular weight is in the preferred embodiment 0.1-30% by weight, more preferably 0.5-25% by weight, and even better 1-20%, e.g. 2-10% by weight of the copolymer.

In a preferred embodiment, the second higher molecular weight copolymer has a higher comonomer content than the first higher molecular weight copolymer. The preferred comonomer content (based on weight%) in the second polymer of higher molecular weight is more than 50%, more preferably more than 100%, and even better by over 300% higher than in the first copolymer with a higher molecular weight. Due to the fact that the lower molecular weight ethylene polymer is a homopolymer, this results in the production of a multimodal polyethylene, more specifically a trimodal composition.

In a preferred embodiment, the second higher molecular weight ethylene copolymer has a density of 875-935 kg / m³. In some embodiments, the second higher molecular weight ethylene copolymer has a density of 885-920 kg / m³ and even better 890-915 kg / m³. However, it's best

EP 2809717 when the first higher molecular weight ethylene copolymer has a density of 890-930 kg / m³ and even better 905-925 kg / m³.

The preferred MFR21 of the second higher molecular weight ethylene copolymer is 0.001-40 g / 10min, more preferably MFR21 is 0.005-30 g / 10min, more preferably 0.006-20g / 10min, and especially preferably 0.007-10g / 10min. , e.g., 0.0075-1 g / 10min.

The preferred FRR (MFR5 / MFR2) of the first higher molecular weight ethylene copolymer is 4.4-20, more preferably 6-18, and still better 7-15.

Mn of the second higher molecular weight ethylene copolymer is 20,000-500,000 g / mol, more preferably 30,000-400,000 g / mol, and even better 40,000-300,000 g / mol.

The average molecular weight (Mw) of the second higher molecular weight ethylene copolymer is higher than the Mw of the first higher molecular weight ethylene copolymer. In a preferred embodiment, the average molecular weight (Mw) of the second higher molecular weight ethylene copolymer is higher by 5-1250 %%, more preferably by 10-1000%, and even better by 15-750%, e.g. 30-300% higher than Mw of the first higher molecular weight ethylene copolymer. Molecular weight (Mw) of the second ethylene copolymer with a higher masie cząsteczkowej w preferowanym wykonaniu to 100.000-3.000.000 g/mol, a lepiej 150.0002.500.000 g/mol, a jeszcze lepiej 200.000-2.000.000 g/mol, a szczególnie preferowana 500.0001.500.000. Polimer można uznać za kopolimer etylenu o ekstremalnie wysokiej masie cząsteczkowej.

Preferowany Mw/Mn pierwszego kopolimeru etylenu o wyższej masie cząsteczkowej to 3-30, a lepiej 4-25, a jeszcze lepiej 5-23.

Preferowana ilość drugiego kopolimeru etylenu o wyższej masie cząsteczkowej zawartego w polietylenie stanowiącym niniejszy wynalazek to 0.5-9.5 %. W preferowanym wykonaniu zawartość drugiego kopolimeru etylenu o wyższej masie cząsteczkowej jest wyższa niż 1.0% np. 1.2% lub 1.5% masy. Preferowana masa drugiego kopolimeru etylenu o wyższej masie cząsteczkowej to mniej niż 9.5% masy, np. 9.0% lub 8.5% masy. W niektórych polietylenach wynalazku preferowana ilość drugiego kopolimeru etylenu o wyższej masie cząsteczkowej wynosi 1.2 do 8.5 % wagowo, a lepiej 1.0-7.5 % wagowo, a jeszcze lepiej 1.5-6.0 % wagowo, a jeszcze bardziej preferowana 3-6 % wagowo, w oparciu o maspolyethylene.

Without going too far into the theory, it is assumed that the addition of a relatively large amount of comonomer to a small amount of ethylene copolymer means that the comonomer is introduced into longer copolymer chains and shorter chains. Thus, the number of side chains in the copolymer increases and thus increases the interconnectedness of the polymer chains. We believe that this will affect both the better properties of SCG and at the same time, due to only a small amount of polyethylene modification, there will be no or minimal negative impact on RCP, observed in older versions.

In a preferred embodiment, the second higher molecular weight ethylene copolymer is a Ziegler Nata polymer, i.e. it has been produced in Ziegler Natta catalysed polymerization.

Process

The polyethylene included in the present invention is produced in a multi-stage polymerization process. When the polymer is produced in a multistage process, the reactors can be set in parallel or in series, however a serial arrangement is preferred. The production of components in a parallel process means the need to mix powders and their extrusion for homogenization.

- EP 2809717

Catalyst system

The polyethylene included in the present invention may be prepared using a Ziegler-Natta catalyst, a single catalyst system or also further catalyst hybrids. However, in a preferred embodiment, the polyethylene is made using one or more Ziegler Natta catalyst systems. It is preferred to use a single Ziegler Natta catalyst system, e.g. for each step of a multistage polymerization.

The Ziegler Natta system in the preferred embodiment consists of a transition metal component and an activator. The preferred transient metal component when added to the polymerization reaction is contained in solid particles. In a preferred embodiment, at least some activator, also sometimes called a co-catalyst, is added to the polymerization reaction in a liquid form or solution.

Ziegler Natta catalyst system

Transition metal component

The active element of the catalyst system is the transition metal. In particular, transition metals of Group IV (e.g., Ti, Zr, Hf) or V (e.g. V, Nb, Ta) are preferred, in particular those of Group IV, especially Ti. Particularly preferred Ziegler Natta catalysts are Group IV transition metals (e.g. Ti).

During the preparation of the catalyst system, it is preferred to use transition metals in the form of alkoxyl compounds or halides, especially chlorides. It is particularly preferred to use Ti, which in the stage of its introduction into the catalyst preparation system is TiCl4.

The transition metal content of the final catalyst based on the dry weight of the catalyst is in the preferred embodiment 0.1-5 mmol / g.

In a preferred embodiment, the solid catalyst particles also contain a Group II metal, preferably a magnesium compound, preferably a Mg-Cl compound, e.g. MgCl2.

The magnesium compound may be introduced into the catalyst as a magnesium compound (e.g., MgCl2) but in a preferred embodiment it is formed in situ during the preparation of the catalyst to ensure high dispersion, contact with the transition metal and porosity. One skilled in the art knows how to perform such an in situ reaction.

The Mg content in the final solid catalyst based on the dry weight of the catalyst is in the preferred embodiment 1-25% by weight.

Material that builds particles

The material that builds up the particles present in the catalyst system that Ziegler Natta consists of may be an inorganic medium such as silicide, clays, titanium, aluminum and titanium silicates or Mg or Ca compounds such as chlorides, oxychlorides, alkyls and alcohols, or metal salts with organic anions. In an even more preferred embodiment, the material is MgCl2. It is particularly advantageous in polymerization to produce a second high molecular weight ethylene copolymer.

After the addition, the material that forms the particles constitutes 30-90% of the final, dry mass of the catalyst. If the Mg-Cl compound is composed of the molecular-forming material, the molecular-building material also functions as the magnesium compound described above. If material

The metal oxide particles are the building blocks, the metal oxide particles usually define the external morphology of the system and other components of the catalyst system will be synthesized in its pores.

Activator and additional components

The activator is a compound capable of activating the transition metal component. Sometimes it is called a co-catalyst. Useful activators include, but are not limited to, aluminum alkyls and aluminum alkoxy compounds. Particularly preferred activators are aluminum alkyls, in particular aluminum (III) alkyl (e.g., aluminum trimetide, aluminum triethyl and aluminum isobutyl). The activator in the preferred embodiment is added in a large amount to the transition metal component. For example, in the case of a positive alkyl aluminum promoter, the molar ratio of gin in the transition metal activator in the transition metal component is 1 to 500 mol / mol, more preferably 2 to 100 mol / mol, e.g. 5 to 50 mol / mol. The activator is usually not part of a permanent

The Ziegler Natta catalyst system may additionally consist of co-activators and / or modifiers. Thus, two or more aluminum alkyl compounds may be used as described above and / or the catalyst system elements may be combined with other types of ethers, esters, silicon ethers etc. to modify the activity and / or selectivity of the catalyst system, as is known in the art. in art.

Preparation of the catalyst system

The catalyst system that the Ziegler Natta catalyst consists of can be prepared by procedures known in the art, e.g. described in US6828267, US4081674 and US4792588.

The catalyst system solids may optionally be rinsed before use to remove the unbound transition metal. The final catalyst system particle added to the polymerization should be such that only very small amounts of the transition metal can be separated in the alkanes at 80 ° C.

In a preferred embodiment the particle size of the catalyst system is in the range of 1 to 250 μm, more preferably 4 to 100 μm, and even better 6 to 30 μm, e.g. 10 to 25 μm. Preferred molecules are spherical.

The surface area of ​​the catalyst system particles in the preferred embodiment ranges from 1 to 500 m²/ g, preferably 2-300 m²/ G. The pore volume of the catalyst system particles in the preferred embodiment is in the range of 0.1-5 cm³/ g, preferably 0.2-1.5 cm³/ G.

Single catalyst system

General local catalyst

The catalyst system, which consists of a single catalyst that can be used in the process covered by this invention is a metallocene-containing catalyst system. Systems of such catalysts are well known in the art, e.g. from WO98 / 02246.

The catalyst system may be supported or unsupported, but in a preferred embodiment it is supported. The supported catalyst system can be created by impregnating active precursors in it. Alternatively, the catalyst system can be synthesized by direct generation of solid particles from liquid components

- EP 2809717 starter, omitting a separate impregnation stage. The preferred catalyst system consists of a single local catalyst on the support.

The single catalyst system preferably consists of a carrier, an activator and at least one reaction precursor in the form of a transition metal (metallocene). The activator may be aluminum oxane, borate or borate, but preferably aluminum oxalate. The preferred active precursor is metallocene.

The morphology of the catalyst and carrier

The system of a single reaction catalyst in the preferred embodiment has a powdered form. The catalyst system is in the form of particles with an average particle size of 1 to 250 microns, preferably 4 to 150 microns. The preferred catalyst system is a form of loose powder.

Suitable carrier materials for use in a single reaction catalyst system are well known in the art. The carrier is preferably an inorganic material, e.g. an oxide or silicate and / or aluminum or also MgCl2. In a preferred embodiment, the carrier is a silicone and / or aluminum oxide. The silicon dioxide is even better.

In a preferred embodiment, the carrier molecules have an average size of from 1 to 500 microns, preferably 3 to 250 microns, e.g. 10 to 150 microns. Particles of appropriate sizes can be obtained by sieving to eliminate too large molecules. Screening can be carried out before, during and after the preparation of the catalyst system. The preferred shape of the particles is spherical. The preferred surface area of ​​the carrier varies from 5 to 1200 m²/ g, preferably 50 to 600 m²/ G. The preferred pore volume of the carrier varies between 0.1 and 5 cm³/ g, preferably 0.5-3.5 cm³/ G.

Ideally, the carrier is dehydrated before use. It is particularly advantageous to heat the support at a temperature of from 100 to 800 ° C, more preferably 150 to 700 ° C, e.g. about 250 ° C before use. Dehydration is to last from 0.5 to 12 hours.

Carriers suitable for the catalyst system described herein are commercially available, e.g., Grace and PQ.

activator

Preference is given to the presence of an aluminumoxate catalyst activator in the system. The oxyan in the preferred embodiment is oligomeric. Even more preferred is a cage structure (e.g., polycyclic) of molecules with an approximate formula, e.g. (Al1.4R0.8O) n where n is in the range of 10-60, R is an alkyl group e.g. a C1-20 alkyl group, for example Metyloxyanglin (MAO) is a mixture of oligomers with a molecular weight distribution with a preferred molecular weight between 700 and 1500. MAO is the preferred aluminum oxal for use in the catalyst system.

Aluminum oxalate may be modified with alkyl or aluminum-aluminum oxide. Particularly preferred modifiers are aluminum alkyls and in particular aluminum (III) alkyls such as trimetycol and aluminum tri-isobutyl. Aluminum trimetics are especially preferred.

Aluminum oxides, such as MAOs, which are suitable for the catalyst system described herein are commercially available, e.g. those offered by Albemarle or Chemtura.

It is also possible to prepare the activator in place, e.g. by slow hydrolysis of aluminum trimethyl in the pores of the carrier. This process is well known to the industry.

- EP 2809717

An alternative is to use boron based activators. Preferred boron activators are those in which the boron is connected to at least 3 fluorinated phenyl rings as described in EP520732.

Alternatively, it may be used as a solid surface activating carrier as described in US 7312283. These are solid, particulate, high porosity inorganic oxides exhibiting Lewis-or Bornsted acidity, subjected to an electron-receiving component, typically anion, and then calcined.

Active transition metal precursor

Typically, the metal of the transition metal precursor is a 16-electron metal, however, it may sometimes have less electrons, e.g. in Ti, Zr or Hf compounds.

Preferred active transition metal precursor is metallocene.

The preferred metallocene composition is a metal coordinated with at least one or more binding ligand. The metal is preferably Zr, Hf or Ti and especially Zr or Hf. The η ligand binding is preferably η5-ring, e.g. a homo or heterocyclic cyclopentadienyl group, with optional substitutes attached. The two η linking ligands can be bridged.

The preparation of metallocenes can be carried out in accordance with, or analogously to, the methods described in the literature, it is also within the skill of a chemist skilled in the art of polymers.

Other types of single reaction precursors are described in:

GJP Britovsek and others.: The Search for New-Generation. Olefin Polymerization Catalysts: Life beyond Metallocenes, Angew. Chemie Int. Ed., 38 (1999), p. 428.

H. Makio et al .: FI Catalysts: A New Family of High Performance Catalysts for Olefin Polymerization, Advanced Synthesis and Catalysis, 344 (2002), p. 477.

The activators of the Dupont-Brookhart type reaction are described in US5880241.

Preparation of the catalyst system

The preparation of a single catalyst system can be carried out in accordance with methods known in the industry. For example, methods for placing a single catalyst in a ready vehicle and aluminum oxime can be found in EP279863, WO93 / 23439, EP 793678, WO96 / 00245, WO 97/29134. Alternative methods for the suspension of the catalyst with the aid of ready carriers and boron activators can be found in WO91 / 09882 and WO 97/31038. Methods for obtaining catalyst powder systems without using ready carriers can be found in EP 810344 and EP 792297.

The use of a Ziegler Natta catalyst is preferred for a single reaction catalyst, as the Ziegler Natta catalyst makes it easier to obtain very high molecular weight and a relatively high combination of co-monomers with regard to one of the polymerization steps.

A multi-stage polymerization process

The polyethylene of the present invention is prepared in a multistage polymerization process in which the polymerization is carried out in at least three steps. In a preferred embodiment, the polyethylene is produced in three steps or stages, and even better in three separate reactors. A continuous or semi-continuous process is preferred.

The polyethylene of the present invention can be prepared, for example, in suspension, gas and / or solution polymerizations. Polymerization of the gas phase and suspension are called together

EP 2809717 polymerization of the molecular form. In a preferred form, the polymerization process of the polyethylene covered by this invention takes the form of molecular polymerization. Polymerization carried out in a conventional loop or in stirred tank reactors is even more preferred, tank reactors equipped with agitators are preferred. The preferred diluent is a hydrocarbon with 3 to 10 carbon atoms. The best is n-hexane or isobutane. The most preferred is n-hexane.

If present in the reaction, the comonomer is preferably an alpha olefin with 3 to 10 carbon atoms. Propylene, n-butene, n-pentene, 4-methyl-1-pentene, n-hexane or n-octene are preferred. If the diluent is n-hexene, the preferred comonomer is propylene, n-butene, n-pentene or 4-methyl-1-pentene. Even better when the comonomer is n-butene or n-pentene, and preferably n-butene. If the diluent is isobutane, the preferred monomer is nbuten, n-pentene, 4-methyl-1-pentene, hexane or 1-octene. Even better when the comonomer is nbuten, n-pentene, n-hexane or n-octene, and preferably n-hexane.

Hydrogen that acts as a molecular weight regulator is supplied to at least one, and preferably at least two, reactors. In use, the pressure ratio in the reactor between hydrogen and ethylene is 0.001-5.

In a preferred embodiment, the polymerization reactions are carried out as a continuous or semi-continuous process. The monomers, diluent and hydrogen are in a preferred embodiment fed continuously or semi-continuously into the reactor. In addition to the reactor, it is possible to deliver a slurry from any prior reactor in a continuous or semi-continuous manner. The preferred catalyst system, if direct addition is required, is also added to the reactor in a continuous or semi-continuous manner. Even better when the polymer slurry leaves the reactor continuously or semi-continuously. By semi-continuous is meant the addition / reception which takes place at relatively short intervals, e.g. from 20 seconds to 2 minutes for at least 75% (e.g., 100%) of the duration of the polymerization.

The preferred concentration of polymer present in the reactor during the polymerization is in the range from 15 to 55% of the total mass, e.g. the suspension, and more preferably 25 to 50% of the total weight. This concentration can be maintained by controlling the rate of addition of the monomer, the diluent (if present) and the catalyst system, and, to some extent, by the rate of polymer reception, e.g. its suspension from e.g. a slurry reactor.

The gas phase conditions of the polymerization

The conditions for carrying out the gaseous polymerization phase are well known in the art. Each reactor system usually consists of a reactor and a gas recirculation and cooling system, and the recirculation and cooling gas system optionally condenses a portion of the gas. The preferred reaction temperature ranges from 50 to 125 ° C, e.g. 70 to 120 ° C. The preferred reaction pressure is in the range of 1 to 100 bar, e.g. 10 to 30 bar. The preferred total residence time in the reactor is in the range of 2 to 9 hours, e.g. 3 to 7 hours. The presence of inert gases such as nitrogen and low boiling alcohols, e.g. isopentane, is indicated.

In a preferred embodiment, hydrogen acting as a molecular weight regulator is supplied to at least two reactors. In use, the pressure ratio in the reactor between hydrogen and ethylene is 0.001-5.

In a preferred embodiment, the polymerization reactions are carried out as a continuous or semi-continuous process. Thus, monomers, hydrogen, nitrogen and volatile hydrocarbons are provided in

Continuously or semi-continuously into the reactor. In addition to the reactor, polymer powder can be fed continuously or semi-continuously from any prior reactor. The preferred catalyst system, if direct addition is required, is also added to the reactor in a continuous or semi-continuous manner. Even better when the polymer leaves the reactor continuously or semi-continuously. By semi-continuous is meant the addition / reception which takes place at relatively short intervals, e.g. from 20 seconds to 2 minutes for at least 75% (e.g., 100%) of the duration of the polymerization.

Molecular formation processes may have a hybrid nature that consists of treatment in gas phase reactors and suspensions.

The polymerization process in solutions

In this type of process, the polymer in the reactor is in a liquid solution containing the most saturated C6-10 hydrocarbons. The preferred temperature ranges from 90 to 320 ° C. The preferred reaction pressure is in the range of 20 to 200 bar. It is preferred that the reaction pressure be lower in each subsequent step. The preferred total residence time in the reactor ranges from 3 minutes to 1.5 hours. In a preferred embodiment, the diluent is removed from the polymer by removing the volatile component from the polymer melt.

The first preferred process

One of the preferred processes consists of the following steps (a) - (c):

(a) polymerizing ethylene in the first reactor to produce a lower molecular weight (LMW) ethylene homopolymer;

(b) polymerizing the ethylene and the α-olefin comonomer in the second reactor to form the first higher molecular weight ethylene (HMW1) copolymer; and (c) polymerizing ethylene and an α-olefin comonomer in the third reactor to form a second higher molecular weight ethylene (HMW2) copolymer.

In the first preferred process of the invention, the multimodal polyethylene is produced by producing components of the ethylene polymer in the sequence from the lowest molecular weight to the one with the highest molecular weight, i.e. the molecular weight of the components increases in the order LMW <HMW1 <HMW2. In a further preferred process, the multimodal polyethylene is produced by making its elements of the ethylene polymer in a sequence from the lowest to the highest comonomer content, i.e. the comonomer content of the components increases in the order of LMW <HMW1 <HMW2. In the latter case, the LMW polymer will also generally be the polymer with the lowest molecular weight, but both HMW1 and HMW2 can be the polymer with the highest molecular weight. In a preferred embodiment, the HMW2 has both the highest molecular weight and the highest comonomer content.

In the preferred process, during the polymerization to form the first higher molecular weight ethylene copolymer present in the second reactor is at least a portion of the lower molecular weight homopolymer of ethylene. In a preferred embodiment, the second portion of the lower molecular weight homopolymer of ethylene is passed directly to the polymerization of the second higher molecular weight ethylene copolymer in the third reactor. In a particularly preferred process during such polymerization to produce a second higher molecular weight ethylene copolymer this homopolymer with

The lower molecular weight and the first higher molecular weight copolymer are present in the third reactor.

In the preferred process, virtually all of the catalyst used in the reactors is fed to the first reactor (LMW). In a preferred embodiment, the first reactor is also fed with ethylene and hydrogen. The diluent is also best fed into the first reactor if it is a slurry or dilution phase reactor. Preferred conditions for the polymerization in the first reactor are as follows:

<td>Temperature:</td><td>50 to 270 ° C, more preferably 60 to 120 ° C, even better 50 to 100 ° C, preferably 70 to 90 ° C</td>

<td>Pressure:</td><td>1 to 220 bar, better 1 to 60 bar, even better 1 to 20 bar, preferably 5 to 15 bar</td>

<td>Partial pressure of ethylene:</td><td>1-200 bar, better 1-15 bar, even better 1-10 bar, preferably 2-10 bar</td>

<td>Dwell time:</td><td>1 minute to 6 hours, better 0.5 to 4 hours, even better 1-2 hours</td>

<td>Thinner:</td><td>Either an absent (for gas phase) or saturated C4-10 alkane, preferably hexane or isobutane</td>

<td>Partial H2 pressure ratio:</td><td>ethylene: 5: 1 to 0.5: 1, better 3: 1 to 1: 1</td>

The polymerization in the first reactor in a preferred embodiment produces 30-70% of the total polyethylene, more preferably 35-65% of the mass, and preferably 40-60% of the mass and preferably 45 - 55% of the mass.

The outflow from the first reactor (LMW) in a preferred embodiment is directed to the second reactor. Preferably, 100% of the outflow flows into the second reactor. The most volatile components are best removed from the effluent from the first reactor, e.g. more than 80% hydrogen, and even better at least 90% hydrogen, before entering the stream into the second reactor.

The second reactor is fed with ethylene, a comonomer and optionally hydrogen. The diluent is added in the second reactor in the case of a slurry or solution phase reactor.

The pressure is best lower in the second one than in the first reactor. The preferred conditions for performing the polymerization in the second reactor are as follows:

Temperature: 50 to 290 ° C, better 50 to 100 ° C, even better 60 to 100 ° C, preferably 70 to 90 ° C

Pressure: 1 to 200 bar, better 1 to 60 bar, even better 1 to 15 bar, preferably 2 to 10 bar

Partial pressure of ethylene: 0.2-200 bar, better 0.5-15 bar, even better 0.5-6 bar, e.g. 0.7 to 6 bar

Dwell time: 1 minute to 4 hours, better 0.5 to 4 hours, even better 0.5 to 3 hours, preferably 1-2 hours.

Diluent: Either an absent (for gas phase) or saturated C4-10 alkane, preferably hexane or isobutane

- EP 2809717

Partial pressure coefficient 0.01: 1 to 0.5: 1, better 0.02: 1 to 0.2: 1

H2: ethylene:

Coefficient of partial pressure Ethylene in the reactor: 0.0001: 1 to 0.01: 1, better 0.003: 1 to comonomer: 0.005: 1

The preferred comonomer is 1-butene.

It is preferred to produce 30-70% by weight of the total polyethylene in the second reactor, preferably 35-65% by weight, and preferably 40-60% with an even better option in the form of 40-50% by weight.

It is preferable to direct the entire outflow from the second reactor to the third reactor. Hydrogen is best removed. The third reactor is fed with ethylene and a comonomer. The diluent is added in the third reactor in the case of a slurry or solution phase reactor. The pressure is best lower in the third one than in the first reactor. The preferred conditions for the polymerization in the third reactor are as follows:

Temperature:

Pressure:

Partial pressure of ethylene. Dwell time:

Thinner:

H2 partial pressure:

Corresponding to the comonomer partial pressure to 320 ° C, more preferably 50 to 100 ° C, preferably 60 to 100 ° C, and even better 70 to 90 ° C to 220 bar, preferably 1 to 60 bar, preferably 1 to 10 bar, better 1.5 is 7 bar

0.2-200 bar, better 0.25 to 10 bar, and preferably 0.3-4 bar

0.2 minutes to 2 hours, better 2 minutes to 1 hour, preferably 5 to 30 minutes

Either an absent (for gas phase) or saturated C4-10 alkane, preferably hexane or ethylene isobutane: 0.000: 1 to 0.05: 1, preferably 0.000: 1 to 0.01: 1

Ethylene in the reactor: 0.001: 1 to 0.2: 1, preferably 0.003: 1 to 0.03: 1

The preferred comonomer is 1-butene.

The molar ratio of comonomer and ethylene in the third reactor is 1.5 to 20 times, more preferably 2-15 times, and preferably 3-10 times more than the molar ratio of comonomer and ethylene in the second reactor.

It is preferred to produce 0.5 to 9.5% by weight of the total polyethylene in the third reactor. It is preferred to produce a minimum of 1.0% by weight, e.g. 1.2 or 1.5% by weight of the total polyethylene in the third reactor. It is preferred to produce less than 9.5% by weight, e.g. 9.0% or 8.5% by weight of the total polyethylene in the third reactor. It is particularly preferred to produce 1.2 to 8.5%, even better 1.0-7.5% by weight, and preferably 1.5 to 6% by weight, and even better 3-6% by weight of the total polyethylene.

After polymerization in the third reactor, the polyethylene is best separated by centrifugation or flash distillation.

The preferred features of the polymer, i.e. the first lower molecular weight ethylene homopolymer and the first and second higher molecular weight ethylene copolymers, are described above.

Optionally, the polymerization in the second and third reactors can be carried out as polymerization in different zones, under different polymerization conditions in a single reactor vessel. However, this is not the preferred method.

- EP 2809717

In a second preferred process of the invention, polyethylene is prepared by preparing ethylene polymer components in the order of a lower molecular weight ethylene homopolymer, a second higher molecular weight ethylene copolymer and, finally, a first higher molecular weight ethylene copolymer.

This preferred process consists of the following steps (a) - (c):

(a) polymerizing ethylene in the first reactor to produce a lower molecular weight (LMW) ethylene homopolymer;

(b) polymerizing the ethylene and the α-olefin comonomer in the second reactor to form a second higher molecular weight ethylene copolymer (HMW2); and (c) polymerizing ethylene and an α-olefin comonomer in the third reactor to form the first higher molecular weight ethylene (HMW1) copolymer.

In the second preferred process of the invention multimodal polyethylene is produced by producing ethylene polymer components in the sequence from the lowest molecular weight, then the one with the highest molecular weight, and finally the second highest molecular weight, i.e. the molecular weight of the components increases in LMW sequence HMW1 &lt;Hmw2. In a further preferred process, the multimodal polyethylene is produced by making its elements of the ethylene polymer in the sequence from the lowest to the highest after the second highest comonomer content, i.e. the comonomer content of the components increases in the order LMW &lt;HMW1 &lt;HMW2. In the latter case, the LMW polymer will also generally be the polymer with the lowest molecular weight, but both HMW1 and HMW2 can be the polymer with the highest molecular weight.

The preferred process is shown in Figure 1, described in more detail below.

In a preferred process, during the polymerization to produce a second higher molecular weight ethylene copolymer, the second reactor is present in at least a portion of the lower molecular weight homopolymer of ethylene. In a preferred embodiment, only a portion of the lower molecular weight homopolymer of ethylene is present in the second reactor. Preferably, the second portion of the lower molecular weight ethylene homopolymer is passed directly to the polymerization of the first high molecular weight ethylene copolymer in the third reactor. In a particularly preferred process during such polymerization to produce the first higher molecular weight ethylene copolymer, the lower molecular weight homopolymer and the second higher molecular weight copolymer are present in the third reactor.

In the preferred process, virtually all of the catalyst used in the reactors is fed into the first reactor. In a preferred embodiment, the first reactor is also fed with ethylene and hydrogen. The diluent is also best fed into the first reactor if it is a slurry or dilution phase reactor. Preferred conditions for the polymerization in the first reactor are as follows:

Temperature: 50 to 270 ° C, more preferably 50 to 120 ° C, even better 50 to 100 ° C, preferably 90 ° C

Pressure: 1 to 220 bar, better 1 to 70 bar, even better 1 to 20 bar, preferably 2 to 50, and preferably 3 to 20 bar, e.g. 5 to 15 bar

EP 2809717

Partial pressure 0.2 to 200 bar, preferably 0.5 to 15 bar, preferably 1-10 bar, e.g. 2-10 bar ethylene:

Dwell time:

Thinner:

minute to 6 hours, better 0.5 to 4 hours, even better 1-2 hours

Either an absent (for the gaseous phase) or a saturated C4-10 alkane better hexane or isobutane, and most preferably hexane as a diluent

Partial pressure ethylene: 5: 1 to 0.5: 1, better 3: 1 to 1: 1 H2:

The polymerization in the first reactor in the preferred embodiment produces 30-70% by weight of the total polyethylene, more preferably 35-65% by weight, and preferably 40-60% by mass, and preferably 45 - 55% by mass.

The outflow from the first reactor (after removal of hydrogen) can be directed entirely to the second reactor. However, it is best if it is divided between a direct inflow to the second and third reactor. In a preferred embodiment, 5-100% of the flow passes through the second reactor, more preferably 10-70%, preferably 15-50%, e.g. 20-40%. Optionally, undesired components are removed in the stream leaving the first reactor, e.g. so that more than 96% hydrogen is removed from the outflow of the first reactor before it reaches the second reactor and over 80% hydrogen removed before the stream reaches the third reactor directly. The streams entering directly into the second and third reactors thus consist mainly of polyethylene and a diluent. In a preferred embodiment, the whole (e.g. all) of hydrogen is removed before the streams are separated. Optional division of the streams can be achieved by means of mass flow control, e.g. suspensions and / or using volumetric inflow inputs to switch the flow between the second and third reactors at short intervals.

The second reactor is fed with ethylene and a comonomer. A significant part of the comonomer fed is a non-purified reverse flow from the third reactor. The diluent is added in the second reactor in the case of a slurry or solution phase reactor. Hydrogen is also optionally added. The preferred conditions for performing the polymerization in the second reactor are as follows:

Temperature:

Pressure:

Partial pressure of ethylene:

Partial pressure H2: ethylene Dwell time:

Thinner:

The ratio of partial pressures of comonomer: ethylene in the reactor to 290 ° C, more preferably 55 to 120 ° C, even better 50 to 100 ° C, e.g. 60 to 100 ° C, and even better 70 to 90 ° C to 220 bar, better 0.75 up to 70 bar, even better 1 to 50 bar, preferably 1 to 16 bar, e.g. 5 to 11 bar

0.2 to 200 bar, better 0.3 to 10 bar, even better 0.3 to 4 bar

0.000: 1 to 0.05: 1, and better 0.000: 1 to 0.01: 1

0.2 minutes to 1 hour, better 1 minute to 1 hour, even better 2 to 20 minutes

Either an absent (for gas phase) or saturated C410 alkane better hexane or isobutane, and most preferably hexane as a diluent

0.001: 1 to 0.2: 1, better 0.003: 1 to 0.03: 1

- EP 2809717

The preferred comonomer is 1-butene, 1-pentene, 1-hexene or 1-octene, and preferably 1-butene.

It is preferred to produce 0.5 to 9.5% by weight of the total polyethylene in the third reactor. It is preferred to produce a minimum of 1.0% by weight, e.g. 1.2 or 1.5% by weight of the total polyethylene in the third reactor. It is preferred to produce less than 9.5% by weight, e.g. 9.0% or 8.5% by weight of the total polyethylene in the third reactor. It is particularly preferred to produce 1.2 to 8.5%, even better 1.0-7.5% by weight, and preferably 1.5 to 6% by weight, and even better 3-6% by weight of the total polyethylene.

It is preferable to direct the entire outflow from the second reactor to the third reactor. This flow consists mainly of polyethylene and a diluent. Optional volatiles are partially removed from the stream before it enters the third reactor, e.g. a volatile comonomer (e.g., 1-butene) can be removed from the stream. Each polymer stream from the first reactor that does not enter the second reactor is best directed directly to the third reactor.

The third reactor is fed with ethylene, comonomer and hydrogen. The diluent is added in the third reactor in the case of a slurry or solution phase reactor. In a preferred embodiment, a large portion of the comonomer fed is derived from the flow from the second reactor. The preferred conditions for the polymerization in the third reactor are as follows:

Temperature:

Pressure:

up to 320 ° C, preferably 50 to 120 ° C, even better 50 to 100 ° C and preferably 70 to 90 ° C to 220 bar, better 1 to 70 bar, even better 1 to 50 bar, preferably 1 to 15 bar, and preferably 2 to 10 bar

Partial pressure of ethylene: 0.4-200 bar, preferably 0.5 to 15 bar, and preferably 0.5-6 bar

Dwell time:

Thinner:

minute to 4 hours, better 0.5 to 4 hours, even better 1-2 hours

Either an absent (for the gaseous phase) or a saturated C4-10 alkane better hexane or isobutane, and most preferably hexane as a diluent

Pressure ratio 0.01: 1 to 0.5: 1, better 0.02: 1 to 0.2: 1 partial H2: ethylene:

The comonomer partial pressure ratio:

Ethylene in the reactor: 0.0001: 1 to 0.01: 1, better 0.0003: 1 to 0.005: 1

The preferred comonomer is 1-butene, 1-pentene, 1-hexene or 1-octene, and preferably 1-butene.

The molar ratio of comonomer and ethylene in the third reactor is 5-90% of that of the second reactor, more preferably 10-40% of that of the second reactor. The preferred pressure is lower in the third reactor than in the second reactor.

It is preferred to produce 30-70% by weight of the total polyethylene in the second reactor, preferably 35-65% by weight, and preferably 40-60% with an even better option in the form of 40-50% by weight.

Optionally, a part of the outflow from the third reactor returns to the second reactor.

After polymerization in the third reactor, the polyethylene is best separated by centrifugation or flash distillation.

- EP 2809717

The preferred features of the polymer, i.e. the first lower molecular weight ethylene homopolymer and the first and second higher molecular weight ethylene copolymers are described above.

This polymerization is applicable to the preparation of multimodal, e.g. trimodal ethylene. Thus, we described the process of acquiring polyethylene consisting of:

(i) 20-70% by weight of a low molecular weight homopolymer of ethylene (ii) 20-70% by weight of the first higher molecular weight ethylene copolymers;

and (iii) 0.5-9.5% by weight of the second higher molecular weight ethylene copolymer, this process consists of the following steps (a) - (c):

(a) polymerizing ethylene and, optionally, the α-olefin comonomer in the first reactor to produce a lower molecular weight (LMW) ethylene polymer;

(b) polymerizing ethylene and optionally an α-olefin comonomer in the second reactor to form a second higher molecular weight ethylene (HMW2) copolymer; and (c) polymerizing ethylene and optionally an α-olefin comonomer in the third reactor to form the first higher molecular weight ethylene (HMW1) copolymer.

Preferred polyethylene is multimodal. Preferred polyethylene has a multimodal molecular weight distribution. Polyethylene with a multimodal composition is preferred.

In the polyethylene preparation process, polyethylene is prepared by preparing ethylene polymer components in the lower molecular weight polymer sequences, an ethylene copolymer with a second higher molecular weight, and finally a first higher molecular weight ethylene copolymer. In a preferred process, polyethylene (e.g., multimodal) is produced by preparing its polyethylene elements in the order of the lowest molecular weight, the highest molecular weight, and finally the second highest molecular weight, i.e. the molecular weight of the components, changes in LMW &lt;HMW1 &lt;HMW2 order. In a further preferred second process, polyethylene (e.g., multimodal) is produced by making its elements of the ethylene polymer in a sequence from the lowest to the highest after the second highest comonomer content, i.e. comonomer content of the components increases in order of LMW &lt;HMW1 &lt;HMW2. In the latter case, the LMW polymer will also generally be the polymer with the lowest molecular weight, but both HMW1 and HMW2 can be the polymer with the highest molecular weight. In a preferred embodiment, the HMW2 has both the highest molecular weight and the highest comonomer content.

In a preferred process, during the polymerization to produce a second higher molecular weight ethylene copolymer, at least a portion of the lower molecular weight ethylene polymer is present in the second reactor. In a further preferred process, only a portion of the lower molecular weight ethylene copolymer is transferred directly for the polymerization of the first higher molecular weight ethylene copolymer in the third reactor. In a further preferred process during such polymerization producing the first higher molecular weight ethylene copolymer, the lower molecular weight ethylene polymer and the second higher molecular weight ethylene copolymer are present in the third reactor. Thus, any lower molecular weight ethylene polymer

EP 2809717 absent in the second reactor in the best embodiment is fed directly into the third reactor.

Optionally, the polymerization in the second and third reactors can be carried out as polymerization in different zones, under different polymerization conditions in a single reactor vessel. However, this is not the preferred method.

After polymerization in the third reactor, the polyethylene is best separated by centrifugation or flash distillation.

In this process, the lower molecular weight ethylene polymer is the best homopolymer of ethylene. The preferred first higher molecular weight ethylene polymer is an ethylene copolymer. The preferred second higher molecular weight ethylene polymer is an ethylene copolymer. A preferred amount of the second higher molecular weight ethylene polymer is 0.5 to 30% by weight, preferably 1 to 15% by weight, even better 1.5 to 9.5% by weight, and preferably 1.2 to 8.5% by weight, e.g. 1.5 to 6% by weight.

In this process, it would be best if the second higher molecular weight ethylene polymer had a higher percentage of (mass) comonomer than the first higher molecular weight ethylene polymer. A second higher molecular weight ethylene polymer with a comonomer content of 1 to 20% by weight is preferred. A preferred second higher molecular weight ethylene polymer consists of one or more α-olefin comonomers, preferably selected from propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, and mixtures thereof . An especially preferred copolymer of the second higher molecular weight ethylene polymer is a 1-butene copolymer.

The preferred copolymer content in the first higher molecular weight ethylene polymer is 0.3 to 2.5% by weight. The preferred first higher molecular weight ethylene polymer consists of one or more α-olefin comonomers, preferably selected from propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, and mixtures thereof . An especially preferred copolymer of the first higher molecular weight ethylene polymer is a 1-butene copolymer.

In such a process, it is preferred that the second high molecular weight copolymer has a higher average molecular weight than the first high molecular weight copolymer. It is preferred that the second high molecular weight copolymer has an average molecular weight of 200,000 to 2,000,000 g / mol. It is preferred that the first high molecular weight copolymer has a molecular weight of 200,000 to 700,000 g / mol.

In such processes, the content of the first high molecular weight copolymer in the amount of 40-60% by weight is preferred. The preferred lower molecular weight ethylene polymer is ethylene homopolymer. The preferred MFR2 of the lower molecular weight polymer is 50-4000 g / 10min.

In such processes, the preferred polyethylene has a density of 945-962 kg / m³ and / or MFR5 in the amount of 0.15-0.6 g / 10min.

Polymerization with Ziegler Natta catalyst is preferred in the processes.

Further preferred features for each polymer component and polyethylene are described above. In addition, the preferred conditions for carrying out each polymerization step have also been described above with reference to the second preferred process.

Preferred processes of the invention are shown schematically in Figure 1. Figure 1 shows the flow from the first reactor (LMW polymer) divided between the second (HMW2 polymer) and the third (HMW1 polymer) reactor. Figure 1 also shows how preferably this process allows

- EP 2809717 solvent and / or comonomer recirculation. The hatching lines in Figure 1 illustrate the recycling of the comonomer separated from the polyethylene product in each reactor. The thin solid lines in Figure 1 illustrate the recycling of the diluent, both in purified and unpurified form. The term crude diluent as used herein refers to a diluent in which the wax (the hexane fraction of the PE fraction) has not been removed and the comonomer has not been completely removed. In contrast, hydrogen can optionally and is recommended, removed, e.g. before recirculation to the third rector. Diluted diluent means a diluent that is essentially free of wax and comonomer.

In preferred processes, the purified diluent is 30 to 100% of the recovered diluent. It is preferred to feed the first (LMW polymer) reactor with a purified diluent. It is preferable to supply the second (HMW2 polymer) reactor with a crude and / or purified diluent. It is preferred to feed the third (HMW1 polymer) reactor with a non-purified and / or purified diluent. In addition, a certain amount (e.g., 0.1 to 4% by volume) of the fresh diluent is added to the reactor system, e.g. to make up for the diluent loss.

In a further preferred process, the first (LMW polymer) second (HMW2 polymer) and third (HMW1 polymer) reactor is fed with fresh comonomer and / or recirculated co-monomer. It is preferred that the first (LMW polymer) reactor is not comonomer. In a preferred embodiment, more than 40% by weight, preferably more than 60% by mass (e.g., 40 to 80% by mass) of the total comonomer fed to the third (HMW1) reactor comes from the diluent and the flow from the second (HMW2) reactor.

The advantage of the process shown in Figure 1 above the conventional process, in which polymers with increasing molecular weight and increasing comonomer content are produced, consists in:

• Reduction of the total mass of comonomer flows to be separated, as the comonomer concentration is usually lower in the HMW1 polymer reactor than in the HMW2 polymer reactor. This makes separation of the comonomer from the diluent and polyethylene wax easier and the processing of the comonomers easier and less expensive due to the smaller volumes. It is also an advantage in cases where a part of the comonomer undergoes undesirable chemical reactions in the recirculation system. In transforming a product that requires less comonomer, the volume of excess comonomer storage will be less.

• The volume of the HMW2 polymer reactor can be much lower, both because the concentration of the catalyst is much higher here, and because the pressure will usually be higher than at the beginning of the process. It is also easier to admix a typically high comonomer concentration in the HMW2 polymer reactor, as the residence time of the catalyst in the reactor system at the HMW2 polymer stage is lower than in the conventional process, and the ability of the Ziegler catalyst to combine the comonomer decreases with the residence time.

• Most of the recycled thinner can be used as a non-purified diluent.

• Less catalyst consumption with an identical cumulative residence time (see examples) in all three reactors.

• It is possible to re-use the mixture of comonomer and diluent from the second reactor.

• It is possible to re-use the diluent from the third reactor back in the first reactor without removing comonomer, in case the LMW polymer is a copolymer or when small amounts of comonomer are acceptable in the LMW polymer.

It should also be noted that although polymerization is described herein with reference to a three-step sequence and three reactors, it is obvious that it can be embodied in a longer (e.g., four or more stepwise) sequence on which additional reactors will be made. For example, regardless of the process used, there may be an additional reactor after the third reactor. In a preferred arrangement, it produces a copolymer. The preferred amount is 1-30% by weight of the total polymer, preferably 2-20% by weight (e.g., 2 to 9.5% by weight) and preferably 3-15% by weight, e.g. 4 to 9.5% by weight. Similarly, there may also be a reactor (e.g., pre-polymerization reactor) before the first reactor described herein.

Further processing

After the final polyethylene is obtained from the slurry reactor, the polymer is recovered, and the diluent is best filtered by flash distillation or filtration. Most of the diluent and unprocessed comonomer is in a preferred embodiment returned to the polymerization reactor (s). In a preferred embodiment, the polymer is then dried (e.g. to remove residual liquid or gas from the reactor). Optionally, the polymer undergoes an ash removal step, i.e. washing with alcohol, optionally mixed with liquid hydrocarbons or water. In the preferred embodiment, there is no ash removal step.

For polyethylene to be transported without problems, both downstream of the polymerization process and outside it, the polyethylene from the reactors is preferably free-flowing, preferably with relatively large molecules or high density, i.e. less than 20% of the polymer powder is less than 100 μm and the density Gross bulk material is higher than 300 kg / m³.

In a preferred embodiment, the processes from polymerization to forming the granules in the extruder are carried out in an inert gas atmosphere (e.g., N2).

In a preferred embodiment, antioxidants (process stabilizers and long-lasting antioxidants) are added to the polyethylene. In this role, all known types of compounds may be used, such as sterically substituted or partially substituted phenols, aromatic amines, aliphatically sterically substituted amines, organic phosphates and sulfur compounds (e.g., thioethers). Other additives (anti-block, batch colors, anti-static agents, slip agents, fillers, UV absorbents, lubricants, acid neutralizers and fluoroelastomers and other polymer treatment agents) can optionally be added to the polymer.

If polyethylene is to be used for the production of a pipe, pigment (e.g., carbon black) is added in the preferred embodiment prior to extrusion. The pigments are best added in the form of the main lot designation.

Polyethylene is best obtained in pellets by extrusion. The preferred gross density of the granulate is over 400 kg / m³ and less than 10% (by weight) of granules measures less than 2mm.

Further additives (e.g., polymers or anti-block agents) can be added after polyethylene granulation. In the case of these additives, it is advisable to add them to the main batches before, for example, melting the granules into products.

Composition (composition) of polyethylene

- EP 2809717

The polyethylene composition of this invention is such that it has at least one of the following characteristics.

Preferred polyethylene has a FNCT time [Full Notch Creep Test] for failure of more than 10 hours, and more preferably higher than 15 hours and preferably higher than 20 hours, e.g. under the conditions described in the examples below maximum time to failure

The FNCT may be, for example, 50 hours.

Preferred polyethylene has a Charpy hammer impact strength at +23 ° C higher than 5 kJ / m²and even better than 10 kJ / m² and preferably higher than 12 e.g. under the conditions described in the examples below. The maximum strength in the Charpy test can be, for example, 50 kJ / m².

Preferred polyethylene has a Shore hardness of at least 30, preferably not less than 40, even better at least 50, and preferably at least 60, e.g. under the conditions described in the examples below. The maximum Shore hardness can be 90.

Preferred polyethylene has a friability below 40%, even better below 30% and preferably below 25 under the conditions described in the examples below. The minimum abrasiveness may be 5%.

An advantage of the polyethylene composition in the present invention is the combination of features that can be achieved. Preferred ethylene compositions of the invention have at least two, and even better three, and preferably all four of the above-mentioned characteristics, e.g. those set out in the examples below:

FNCT time to failure: Charpy hammer: Shore hardness:

attrition:

&gt; 10 hours&gt; 5 kJ / m² &gt; 30 &lt;40%

At best, the polyethylene composition of the present invention has at least two, or even better, three, and preferably all four of the above-mentioned features, e.g. set by the examples given below:

FNCT time to failure: Charpy hammer: Shore hardness:

attrition:

&gt; 20 hours&gt; 12 kJ / m² &gt; 50 &lt;25%

Usage

The polyethylene of the invention may be used for forming such as blow molding or extrusion, such as extrusion of pipes or films. However, it is preferred to use for extrusion, and especially for extrusion of pipes.

The preferred use of the polyethylene of the invention is pipes. HDPE pipes are preferred, e.g. in accordance with PE80 or PE100 standards. The pipes can be used, for example, for supplying water or gas, as sewage, for agricultural applications, suspensions, chemicals, etc.

- 27 - EP 2809717

The invention will now be described with reference to the following non-limiting examples and Figures, of which:

Figure 1 is a scheme of the preferred process of the present invention;

Figure 2 is a graph showing FNCT as a function of the concentration of a second higher molecular weight ethylene copolymer;

Figure 3 is a graph of the Charpy test at +23 ° C as a function of the concentration of the second higher molecular weight ethylene copolymer;

Figure 4 is a graph of the Charpy test at -20 ° C as a function of the concentration of the second higher molecular weight ethylene copolymer;

Figure 5 is a graph of scratchability as a function of the concentration of a second higher molecular weight ethylene copolymer;

Figure 6 is a plot of attrition as a function of the concentration of a second higher molecular weight ethylene copolymer;

Figure 7 is a graph showing Shore hardness versus the concentration of a second higher molecular weight ethylene copolymer.

EXAMPLES

Methods for determining the parameters of polymers

Unless otherwise stated, the following parameters were measured for the polymer samples indicated in the Tables below.

MFR2, MFR5 and MFR21 were measured according to ISO 1133 under loads of 2.16; 5.0, and 21.6 kg. The measurement was made at 190 ° C.

Molecular weight and molecular weight distribution, Mn, Mw and MWD were measured by means of Gel Chromatography (GPC) according to the following method: Average molecular weight Mw and molecular weight distribution (MWD = Mw / Mn where is the number-average molecular weight and Mw mean mass molecular weight) are measured using the method based on ISO 160144: 2003. The Waters Alliance's GPCV2000 instrument, equipped with a refractive index detector and an online viscometer, was used with 1 PLUG GUARD + 3 PLgel MIXED-B and 1,2,4-trichlorobenzene (TCB, stabilized 250 mg / L 2,6-Di tert butyl-4- methylphenol) as a diluent at 140 ° C for a constant flow of 1 ml / min. 200 μl of the sample solution was injected for analysis. The column set was calibrated using universal calibration (according to ISO 16014-2: 2003) and 15 samples of polystyrene (PS) with a narrow molecular weight distribution, in the range of 1.0 to 12,000 kg / mol. The polymers produced by Polymer Labs were Mw / Mn from 1.02 to 1.10. The solid Houwink brand was used for polystyrene and polyethylene (K: 0.19 x 10^-5 dl / gia: 0.655 for PS and K: 3.9 x 10^-4 dl / gia: 0.725 for PE). All samples were prepared by dissolving 0.5-3.5 mg of polymer in 4ml (at 140 ° C) stabilized TCB (identical to mobile phase) and maintained for 3 hours at 140 ° C and another hour at 160 ° C, shaken every time before entering the GPC device.

The melting temperature was measured according to ISO 11357-1 Perkin Elmer DSC-7 differential scanning calorimeter. The soaking curves were recorded from -10 ° C to 200 ° C at 10 ° C / min. At 200 ° C, the sample was held for 10 minutes. The cooling curves were recorded from 200 ° C to -10 ° C every 10 ° C for min. The endotherm of the second heating was adopted as the melting temperature. The degree of crystallization was calculated by dividing

- 280,807 observed melting point by heat of fusion for perfectly crystalline polyethylene, generally accepted at 290 J / g.

Comonomer content (% by weight) was determined using Fourier transform infrared spectroscopy (FTIR), calibrated using C13-NMR.

The density of the materials was measured according to ISO 1183: 1987 (E), method D, with a mixture of isopropanol and water as displacement liquid. The rate of plate cooling at crystallization was 15 C / min. The withdrawal time is 16 hours.

The rheology of polymers determined by frequency shift at 190 ° C under nitrogen, according to ISO 6721-10, using Rheometrics RDA II Dynamic Rheometer, parallel plate geometry, plate diameter 25 mm and gap 1.2 mm. Measurements of dynamic deviation module (G '), losses (G' ') and complex (G *) together with complex viscosity (η *), all as a function of frequency (ω). These parameters are related in the following way: For any frequency ω: Composite module: G * = (G '² + G "²)^{/ 2}. Complex viscosity: η * = G * p. The unit adopted for the module is Pa (or kPa), for viscosity Pa a for frequency (1 / s). η * 0.05 is a complex viscosity at the frequency of 0.05 s^-1 a η * 300 is a complex viscosity at 300 s^-1. According to the empirical Cox-Merz principle for a given polymer and temperature, the complex viscosity versus the frequency measured by this method is the same as the viscosity as a function of the shear rate for a constant flow (e.g., capillary).

The activity coefficient for polymerization weight tests is calculated from the following equation:

Activity coefficient (kg / (g, bar, h) = (Produced polymer_ (kg)) (Quantity of catalyst_ (g)) · (Partial pressure of ethylene_ (bar)) • (Polymerization time - (h))

The PI polydispersity index is the point of intersection of RDA frequency shifts, in which G 'equals G' ', calculated according to the formula: PI = 10⁵Pa / G '.

Specific viscosity: The viscosity was measured in decalin at 135 ° C according to EN-ISO 1628-3: 20 and the specific viscosity was calculated as follows. From the measurements after each of the polymerization stages, the Mv (viscosity of the average molecular weight) was calculated using the MarksHouwing equation, using the pre-exponential factor of 0.0475 ml / g and the exponent 0.725. This allows the calculation of the Mv of the polymer produced in each step with the help of the following additional formulas:

<img file="PL2809717T3_D0001.tif" />

<img file="PL2809717T3_D0002.tif" />

Mw, Mn and Mv are respectively average mass, mean number and average molecular weight viscosity, W is the polymer weight fraction ai is a polymer component, n is the total number of components after a given stage. The first two patterns are accurate, the third is empirical. In addition, Mw / Mn of each polymer component was assumed to be 7.

Methods for determining the composition of the polymer

- EP 2809717

Unless otherwise specified, the following parameters were measured on 4 mm pressure extruded plates using a Collin 300 P pressure extruder, in accordance with ISO 293-186,

ISO1872-2-1197 and SO1873-2-1997;

The FNCT time to failure was measured in accordance with ISO16770 with a load of 8.5 MPa at 80 ° C in 2% by weight Arkopal N110 in demineralized water, on 10 mm "dog cubes" cut from the pressed plate, a notch depth of 1.6 mm around the whole.

The Charpy hammer test was measured according to ISO179-1 / 1eA using slotted sample molds at + 23 ° C and -20 ° C.

Shore hardness: Shore D was measured with the Bareiss digital HHP-2001 type meter until cracks appeared. Sample preparation in accordance with ISO291: 1997.

Abrasion resistance was measured according to ISO 4649, type B test (non-rotating sample) at 10 N at 23 ° C.

Scratch resistance: ironed polymer plate was scratched at + 23 ° C Erichsen scratch resistance tester with 1 mm tip diameter with a normal force of 10 N. The scratched plate was cut transversely to the scratch, micrograph cross-section and the measurement results indicated the scratch depth.

In the case of small-scale experiments, for which it was impossible to perform and test the pipes, the FNCT measurement of the compound is considered to be the SCG measure and the Charpy Hammer test is the measure of RCP. Similarly, the measurement of the sample hardness D is a measure of the likelihood of scratches. Abrasion resistance, according to ISO4649, measures the loss of volume of material tested when treated with an abrasive sheet, which causes the sample to lose mass under strictly defined test conditions. In addition to providing a measure of abrasion, e.g. when transferring abrasive slurries along the surface of the polymer, such as the hardness test, it also provides us with a measure of the likelihood of scratching.

Experimental research

Examples 1-4

A conventional Ziegler-Natta catalyst was used, with Ti as a transition metal. The catalyst is described in US4792588. Titanium content 3.4% by weight.

The polymerization was carried out in an 8 liter bottle equipped with a stirrer and a temperature control system. The catalyst was added in the form of sludge. TEA aluminum triethyl was used as an activator. The same comonomer supply system was used for all procedures. The procedure consisted of the following steps:

The reactor was purged with nitrogen and heated to 110 ° C. The hydrogen was added at a temperature of 20 ° C to a pressure of 3.05 bar. Then 3000 ml of liquid hexane was added and stirring was started, 300 rpm. The reactor temperature was 70 ° C. Co-catalyst and TEA were pre-contacted with sludge for 5 minutes and dissolved in 800 ml of hexane. The ethylene inflow was opened until the pressure reached 12.3 bar. Ethylene was then fed continuously via a flow controller. After sufficient powder was made, the polymerization was stopped and the hexane was evaporated.

Polymerization of the first higher molecular weight ethylene:

EP 2809717

Hydrogen is added at 20 ° C to 0.16 bar. Mixing starts at 300 rpm. The reactor is heated to&gt; 70 ° C. When the temperature reaches 72 °, 35 ml of 1-butene are added together with ethylene, which is fed until the pressure reaches 5.7 bar. Ethylene and 1-butene are then added continuously. After sufficient powder is made, the polymerization is stopped and the hexane is evaporated.

Polymerization of the second polyethylene of higher molecular weight:

The reactor is heated to&gt; 70 ° C. 3000 ml of hexane are added and stirring is commenced at 300 rpm. When the temperature reaches 72 °, 180 ml of 1-butene together with ethylene are added, which is fed until a pressure of 5.3 bar is reached. Ethylene and 1-butene are then added continuously. After sufficient powder is made, the polymerization is stopped and the hexane is evaporated

In Examples 1, 3 and 4, the polymerizations were carried out in order of (i) a lower molecular weight ethylene polymer, (ii) a first higher molecular weight ethylene polymer (HMW1) and (iii) a second higher molecular weight ethylene (HMW2) ethylene. In example 2, the polymerizations were carried out in the order of (i) a lower molecular weight ethylene polymer, (ii) a second higher molecular weight ethylene (HMW2) polymer and (iii) a first higher molecular weight ethylene (HMW1) ethylene. Thus, the LMW polymer is present in the polymerization of HMW2, and both LMW and HMW2 polymer are present in the polymerization of HMW1.

Four comparative polymerizations were made. The first comparative polymerization (C1) was made in the same manner as described above, except that 1-butene was not added to the polymerization of the second higher molecular weight ethylene polymer. Comparative polymerizations (C2 and C4) were made as described above except that the polymerization was stopped after the polymerization of the first higher molecular weight ethylene. Comparative polymerization (C3) was performed with a larger amount (10% by weight) of the second polymer with higher molecular weight (HMW2).

Further details of the polymerization procedure and its results are given in Table 1A, and the details of the polyethylene polymers produced are summarized in Table 1 B below. RI means both polymerization and the polymerization product in the first reactor, RII means both polymerization and the polymerization product in the first and second reactors and RIII means both polymerization and the polymerization product in the first, second and third reactor, i.e. the final product in the form of polyethylene.

- 280 EP 2809717

<td>TABLE 1A</td><td></td><td>Prov. 1 -Rl</td><td>Prov. 1Rll</td><td>Prov. 1Rlll</td><td>Prov. 2-RI</td><td>Prov. 2Rll</td><td>Prov. 2RIII</td><td>Prz.3-RI</td><td>Prov. 3Rll</td><td>Prov. 3Rlll</td><td>Prov. 4-RI</td><td>Prov. 4Rll</td><td>Prov. 4Rlll</td>

<td>The amount of catalyst</td><td>9</td><td>0.156</td><td>0.152</td><td>0.149</td><td>0.13</td><td>0.124</td><td>0.121</td><td>0.172</td><td>0.155</td><td>0.154</td><td>0.14</td><td>0.14</td><td>0.14</td>

<td>Al / Ti</td><td>mol / mol</td><td>20</td><td>20</td><td>20</td><td>20</td><td>20</td><td>20</td><td>20</td><td>20</td><td>20</td><td></td><td>20</td><td>20</td>

<td>Amount of TEA (1 mol / l solution)</td><td>ml</td><td>2.21</td><td>2.16</td><td>2.12</td><td>5</td><td>5</td><td>5</td><td>5</td><td>5</td><td>5</td><td>5</td><td>5</td><td>5</td>

<td>Type of polymerization</td><td></td><td>Homo</td><td>Kopo</td><td>Kopo</td><td>Homo</td><td>Kopo</td><td>Kopo</td><td>Homo</td><td>Kopo</td><td>Kopo</td><td>Homo</td><td>Kopo</td><td>Kopo</td>

<td>Temperature</td><td>° C</td><td>72</td><td>72</td><td>72</td><td>82</td><td>72</td><td>72</td><td>82</td><td>72</td><td>72</td><td>82</td><td>72</td><td>72</td>

<td>Total pressure</td><td>barg</td><td>12.30</td><td>5.70</td><td>5.30</td><td>12.3</td><td>5.4</td><td>5.5</td><td>12.3</td><td>5.6</td><td>5.2</td><td>12</td><td>5.5</td><td>5.5</td>

<td>Thinner type</td><td></td><td>hexane</td><td>hexane</td><td>hexane</td><td>hexane</td><td>hexane</td><td>hexane</td><td>hexane</td><td>hexane</td><td>hexane</td><td>hexane</td><td>hexane</td><td>hexane</td>

<td>Pressure part. thinner</td><td>bar</td><td>2.5</td><td>2.5</td><td>2.5</td><td>2.5</td><td>2.5</td><td>2.5</td><td>2.5</td><td>2.5</td><td>2.5</td><td>2.5</td><td>2.5</td><td>2.5</td>

<td>The amount of thinner</td><td>ml</td><td>3800</td><td>3800</td><td>3800</td><td>3800</td><td>3800</td><td>3800</td><td>3800</td><td>3800</td><td>3800</td><td>3800</td><td>3800</td><td>3800</td>

<td>Mixing speed</td><td>rpm.</td><td>270</td><td>270</td><td>270</td><td>270</td><td>270</td><td>270</td><td>270</td><td>270</td><td>270</td><td>270</td><td>270</td><td>270</td>

<td>Partial pressure of ethylene</td><td>bar</td><td>3</td><td>3</td><td>3</td><td>3</td><td>3</td><td>3</td><td>3</td><td>3</td><td>3</td><td>3</td><td>3</td><td>3</td>

<td>Partial pressure H2 after addition to the empty reactor at 20 ° C for start</td><td>bar</td><td>3.05</td><td>0.12</td><td>0.00</td><td>3.06</td><td>0</td><td>0.09</td><td>3.06</td><td>0.1</td><td>0</td><td>3.06</td><td>0.1</td><td>0</td>

<td>Comonomer type</td><td></td><td>-</td><td>1-butene</td><td>1-butene</td><td>-</td><td>1-butene</td><td>1-butene</td><td>-</td><td>1-butene</td><td>1-butene</td><td>-</td><td>1-butene</td><td>1-butene</td>

<td>Comonomer Party (at the start)</td><td>ml</td><td>0</td><td>20</td><td>180</td><td>0</td><td>130</td><td>15</td><td>0</td><td>10</td><td>140</td><td>0</td><td>10</td><td>140</td>

<td>Comonomer combined</td><td>ml</td><td>0</td><td>58</td><td>240</td><td>0</td><td>160</td><td>38</td><td>0</td><td>38</td><td>170</td><td>0</td><td>38</td><td>170</td>

<td>Comonomer in a diluent</td><td>% by weight</td><td>0</td><td>0.48</td><td>4.28</td><td>0</td><td>3.45</td><td>0.63</td><td>0</td><td>0.57</td><td>3.69</td><td>0</td><td>0.57</td><td>3.69</td>

<td>Polymerization time</td><td>min</td><td>90</td><td>69</td><td>9</td><td>90</td><td>8</td><td>57</td><td>90</td><td>62</td><td>14</td><td>90</td><td>62</td><td>14</td>

<td>Obtained material</td><td>g</td><td>885</td><td>790</td><td>90</td><td>760</td><td>75</td><td>690</td><td>1120</td><td>830</td><td>145</td><td>1120</td><td>950</td><td>50</td>

<td>Activity</td><td>kg PE / g cat, h</td><td>3.8</td><td>4.5</td><td>4.0</td><td>3.9</td><td>4.5</td><td>6</td><td>4.3</td><td>5.2</td><td>4</td><td>5.3</td><td>6.6</td><td>1.5</td>

<td>Activity (or Ti)</td><td>kg PE / g Ti, h</td><td>111</td><td>133</td><td>118</td><td>115</td><td>133</td><td>177</td><td>128</td><td>152</td><td>119</td><td>157</td><td>193</td><td>45</td>

<td>Actual activity of all stages #</td><td>kg PE / g Ti, h</td><td></td><td></td><td>120.4</td><td></td><td></td><td>138.7</td><td></td><td></td><td>136.2</td><td></td><td></td><td>161.0</td>

<td>Actual activity of all steps / Activity on Rl °</td><td></td><td></td><td></td><td>1.08</td><td></td><td></td><td>1.21</td><td></td><td></td><td>1.06</td><td></td><td></td><td>1.03</td>

<td>Productivity</td><td>kg PE / g catalyst</td><td>5.7</td><td>5.2</td><td>0.6</td><td>5.8</td><td>0.6</td><td>5.7</td><td>6.5</td><td>5.4</td><td>0.9</td><td>8</td><td>6.8</td><td>0.4</td>

<td>Productivity (or Ti)</td><td>kg PE / g Ti</td><td>167</td><td>153</td><td>18</td><td>172</td><td>18</td><td>168</td><td>192</td><td>157</td><td>28</td><td>235</td><td>200</td><td>11</td>

<td>The polymer component produced in step</td><td>% by weight</td><td>50</td><td>45</td><td>5</td><td>50</td><td>5</td><td>45</td><td>50</td><td>42.5</td><td>7.5</td><td>50</td><td>47.5</td><td>2.5</td>

<td>Concentration of the suspension (at the end)</td><td>g powder / 1 hexane</td><td>233</td><td>208</td><td>24</td><td>200</td><td>20</td><td>182</td><td>295</td><td>218</td><td>38</td><td>295</td><td>250</td><td>13</td>

# Effective average activity for all steps is the average activity of the catalyst in stages, weighted for stages ° Since all RI polymerization steps were carried out nominally under identical conditions, this ratio gives the average catalyst activity after normalization for deviations in catalyst activity due to error in the amount of catalyst, its poisoning, quantity / quality of cocatalyst.

- EP 2809717

<td>Table 1A (continued)</td><td></td><td>C1- Rl</td><td>C1-RII</td><td>C1-RIII</td><td>C2-RI</td><td>C2-RII</td><td>C3-RI</td><td>C3-RII</td><td>C3-RIII</td><td>C4-RI</td><td>C4-RII</td>

<td>The amount of catalyst</td><td>9</td><td>0.156</td><td>0.152</td><td>0.149</td><td>0.144</td><td>0.140</td><td>0.152</td><td>0.145</td><td>0.142</td><td>0.14</td><td>0.13</td>

<td>Al / Ti</td><td>mol / mol</td><td>20</td><td>20</td><td>20</td><td>20</td><td>20</td><td>20</td><td>20</td><td>20</td><td>20</td><td>20</td>

<td>Amount of TEA (1 mol / l solution)</td><td>ml</td><td>2.21</td><td>2.16</td><td>2.12</td><td>2 04</td><td>1.99</td><td>5</td><td>5</td><td>5</td><td>5</td><td>5</td>

<td>Type of polymerization</td><td></td><td>Homo</td><td>Kopo</td><td>Homo</td><td>Homo</td><td>Kopo</td><td>Kopo</td><td>Kopo</td><td>Kopo</td><td>Homo</td><td>Kopo</td>

<td>Temperature</td><td>° C</td><td>72</td><td>72</td><td>72</td><td>82</td><td>72</td><td>82</td><td>72</td><td>72</td><td>82</td><td>72</td>

<td>Total pressure</td><td>barg</td><td>12.30</td><td>5.70</td><td>5.30</td><td>12.30</td><td>5.70</td><td>12.3</td><td>5.6</td><td>5.2</td><td>12.1</td><td>5.5</td>

<td>Thinner type</td><td></td><td>hexane</td><td>hexane</td><td>hexane</td><td>hexane</td><td>hexane</td><td>hexane</td><td>hexane</td><td>hexane</td><td>hexane</td><td>hexane</td>

<td>Pressure part. thinner</td><td>bar</td><td>2.5</td><td>2.5</td><td>2.5</td><td>2.8</td><td>2.5</td><td>2.5</td><td>2.5</td><td>2.5</td><td>2.8</td><td>2.5</td>

<td>The amount of thinner</td><td>ml</td><td>3800</td><td>3800</td><td>3800</td><td>3800</td><td>3800</td><td>3800</td><td>3800</td><td>3800</td><td>3800</td><td>3800</td>

<td>Mixing speed</td><td>rpm.</td><td>270</td><td>270</td><td>270</td><td>270</td><td>270</td><td>270</td><td>270</td><td>270</td><td>270</td><td>270</td>

<td>Partial pressure of ethylene</td><td>bar</td><td>3</td><td>3</td><td>3</td><td>3</td><td>3</td><td>3</td><td>3</td><td>3</td><td>3</td><td>3</td>

<td>Partial pressure H2 after addition to the empty reactor at 20 ° C for start</td><td>bar</td><td>3.05</td><td>0.16</td><td>0.00</td><td>3.15</td><td>0.13</td><td>3.06</td><td>0.1</td><td>0</td><td>3.05</td><td>0.07</td>

<td>Comonomer type</td><td></td><td>-</td><td>1-butene</td><td>-</td><td>-</td><td>1-butene</td><td>1-butene</td><td>1-butene</td><td>1-butene</td><td>-</td><td>1-butene</td>

<td>Comonomer Party (at the start)</td><td>ml</td><td>0</td><td>35</td><td>0</td><td>0</td><td>35</td><td>0</td><td>10</td><td>140</td><td>0</td><td>35</td>

<td>Comonomer combined</td><td>ml</td><td>0</td><td>102</td><td>0</td><td>0</td><td>106</td><td>0</td><td>38</td><td>170</td><td>0</td><td>106</td>

<td>Comonomer in a diluent</td><td>% by weight</td><td>0</td><td>0.83</td><td>0</td><td>0</td><td>0.84</td><td>0</td><td>0.57</td><td>3.69</td><td>0</td><td>1.68</td>

<td>Polymerization time</td><td>min</td><td>90</td><td>69</td><td>9</td><td>90</td><td>73</td><td>90</td><td>62</td><td>14</td><td>90</td><td>73</td>

<td>Obtained material</td><td>g</td><td>885</td><td>790</td><td>90</td><td>935</td><td>895</td><td>960</td><td>730</td><td>180</td><td>750</td><td>1080</td>

<td>Aktywność</td><td>kg PE/g kat, h</td><td>3.8</td><td>4.5</td><td>4.0</td><td>4.3</td><td>5.3</td><td>4.2</td><td>4.9</td><td>5.4</td><td>3.7</td><td>6.6</td>

<td>Aktywność (wzgl. Ti)</td><td>kg PE/g Ti, h</td><td>111</td><td>133</td><td>118</td><td>127</td><td>155</td><td>124</td><td>143</td><td>160</td><td>108</td><td>195</td>

<td>Aktywność rzeczywista wszystkich etapów #</td><td>kg PE/g Ti, h</td><td></td><td></td><td>120.4</td><td></td><td>139.5</td><td></td><td></td><td>134.1</td><td></td><td>147.0</td>

<td>Aktywność rzeczywista wszystkich kroków/ Aktywność na Rl °</td><td></td><td></td><td></td><td>1.08</td><td></td><td>1.10</td><td></td><td></td><td>1.08</td><td></td><td>0.94</td>

<td>Produktywność</td><td>kg PE/g katalizatora</td><td>5.7</td><td>5.2</td><td>0.6</td><td>6.5</td><td>6.4</td><td>6.3</td><td>5</td><td>1.3</td><td>5.5</td><td>8.1</td>

<td>Produktywność (wzgl. Ti)</td><td>kg PE/g Ti</td><td>167</td><td>153</td><td>18</td><td>191</td><td>188</td><td>186</td><td>148</td><td>37</td><td>162</td><td>237</td>

<td>Komponent polimeru wytworzony w kroku</td><td>% masy</td><td>50</td><td>45</td><td>5</td><td>50</td><td>50</td><td>50</td><td>40</td><td>10</td><td>40</td><td>60</td>

<td>Stężenie zawiesiny (na koniec)</td><td>g proszku/l heksanu</td><td>233</td><td>208</td><td>24</td><td>246</td><td>236</td><td>253</td><td>192</td><td>47</td><td>197</td><td>284</td>

# Skuteczna średnia aktywność dla wszystkich etapów jest średnią aktywnością katalizatora w etapach, ważoną dla etapów °Jako, że wszystkie etapy polimeryzacji RI przeprowadzono nominalnie w identycznych warunkach stosunek ten podaje średnią aktywność katalizatora po normalizacji na odchylenia w aktywności katalizatora z powodu błędu w ilości katalizatora, jego zatrucia, ilości/jakości współkatalizatora.

- 33 EP 2809717

<td>Tabela 1B</td><td></td><td>Prz. 1-RI</td><td>Prz. 1-RII</td><td>Prz. 1 RIll</td><td>Prz. 2-RI</td><td>Prz. 2-RII</td><td>Prz. 2-RIII</td><td>Prz. 3-RI</td><td>Prz. 3-RII</td><td>Prz. 3RIII</td><td>Prz. 4-RI</td><td>Prz. 4-RII</td><td>Prz. 4-RIII</td>

<td>ANALIZA POLIMERU</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>MFR2</td><td>g/10min</td><td>101</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Gęstość</td><td>kg/dm3</td><td></td><td></td><td>948</td><td>970.7</td><td>962.8</td><td>948.3</td><td>969</td><td>952.9</td><td>949.9</td><td></td><td></td><td>948.5</td>

<td>MFR5</td><td>g/10 min</td><td></td><td>0.87</td><td>0.48</td><td></td><td></td><td>0.46</td><td></td><td></td><td>0.48</td><td></td><td></td><td>0.41</td>

<td>η* 0.05 (Reologia)</td><td>Pa s</td><td></td><td></td><td>96.179</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>η* 300 (Reologia)</td><td>Pa s</td><td></td><td></td><td>817</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>PI</td><td></td><td></td><td></td><td>5.2</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Lepkość właściwa w kroku</td><td>ml/g</td><td></td><td></td><td></td><td></td><td></td><td></td><td>75</td><td>799</td><td>1082</td><td></td><td></td><td></td>

<td>Lepkość średnia MW (Mv) w kroku</td><td>kg/mol</td><td></td><td></td><td></td><td></td><td></td><td></td><td>25.8</td><td>673.7</td><td>1 024.0</td><td></td><td></td><td></td>

<td>MFR21 polimeru wytworzonego w kroku (szacunkowo)</td><td>g/10 min</td><td></td><td>0.83</td><td>0.03</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Tabela 1B ciąg dalszy</td><td></td><td>C1 - Rl</td><td>C1-RII</td><td>C1-RIII</td><td>C2-RI</td><td>C2-RII</td><td>C3-RI</td><td>C3-RIII</td><td>C3-RIII</td><td>C4-RI</td><td>C4-RII</td>

<td>ANALIZA POLIMERU</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>MFR2</td><td>g/10min</td><td>102</td><td></td><td></td><td>108</td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Gęstość</td><td>kg/dm3</td><td></td><td></td><td>948</td><td></td><td>948</td><td>969.4</td><td>953.8</td><td>948.7</td><td></td><td>943</td>

<td>MFR5</td><td>g/10 min</td><td></td><td>1.36</td><td>0.49</td><td></td><td>0.47</td><td></td><td></td><td>0.45</td><td></td><td>0.34</td>

<td>eta0.05 (Reologia)</td><td></td><td></td><td></td><td>126.253</td><td></td><td>119.792</td><td></td><td></td><td></td><td></td><td></td>

<td>eta300 (Reologia)</td><td></td><td></td><td></td><td>761</td><td></td><td>888</td><td>77</td><td>660</td><td>676</td><td></td><td></td>

<td>PI</td><td></td><td></td><td></td><td>bez krzyż.</td><td></td><td>4.9</td><td>26.8</td><td>517.9</td><td>534.8</td><td></td><td></td>

<td>MFR21 polimeru wytworzonego w kroku (szacunkowo)</td><td>g/10 min</td><td></td><td>1.4</td><td>0.01</td><td></td><td>0.50</td><td></td><td></td><td></td><td></td><td></td>

- 34 EP 2809717

Wyniki aktywności polimeryzacji były zaskakujące, jako że stosunek Efektywnej średniej aktywności wszystkich kroków ponad Aktywność kroku RI był ponad 10% wyższy w trójetapowym procesie z HMW2 jako drugim krokiem, w porto other three-step and two-step polymerizations. This ratio is an important measure of catalyst consumption in a production plant at a given production scale, with a specific catalyst and residence time. This means that from the production of HMW2 polymer in the second stage of city polymerization in the third, a significant reduction of catalyst consumption in continuous industrial production can be expected. Similarly, the production of HMW2 polymer in the second stage of city polymerization in the third one can expect a significant reduction in catalyst consumption compared to the production of polymer in only two stages. The cost of catalyst consumption is a significant production cost in terms of commodity production, and its reduction is a significant saving for profit.

The polymers were linked to 1550 ppm Irganox B215 (antioxidant) using a Prism16 extruder at UD = 25. The extruder was set at a speed of 1kg / h, 500rpm, without a vacuum with a nitrogen wash. Extruder temperature profile is 180-200x4-180 (die). The granulate was pressed into 4mm tiles in accordance with ISO293-1986, 1872-2 and 1873-2. Samples for testing were made of these plates.

The results are shown in Table 2 below

Table 2

<td>Polyethylene</td><td></td><td>Example 1</td><td>Example 2</td><td>Example 3</td><td>Example 4</td><td>C1</td><td>C2</td><td>C3</td><td>C4</td>

<td rowspan="3">Produced in the polymerization stages (in the order shown)</td><td></td><td>RI</td><td>RI</td><td>RI</td><td>RI</td><td>RI</td><td>RI</td><td>RI</td><td>RI</td>

<td></td><td>RII</td><td>RIII</td><td>RII</td><td>RII</td><td>RII</td><td>RII</td><td>RII</td><td>RII</td>

<td></td><td>RIII</td><td>RII</td><td>RIII</td><td>RIII</td><td>RIII</td><td></td><td>RIII</td><td></td>

<td>Participation; RI / RII / RIII</td><td>% weight</td><td>50/45/5</td><td>5015/45</td><td>50 / 42.5 / 7.5</td><td>50 / 47.5 / 2.5</td><td>50/45/5</td><td>50/50</td><td>50/40/10</td><td>40/60</td>

<td>Komonomer / (C4) in RIII</td><td></td><td>Yes</td><td>Yes</td><td>Yes</td><td>Yes</td><td>No</td><td>-</td><td>Yes</td><td>Yes</td>

<td>MFR 5</td><td>g / 10 min</td><td>0.48</td><td>0.46</td><td>0.48</td><td>0.41</td><td>0.49</td><td>0.47</td><td>0.45</td><td>0.34</td>

<td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>Density</td><td>kg / m³</td><td>948</td><td>948.3</td><td>949.9</td><td>948.5</td><td>948</td><td>948</td><td>948.7</td><td>943</td>

<td>FNCT time to failure *</td><td>h</td><td>31 [11]</td><td>30 [2]</td><td>26 [4]</td><td>45 [3]</td><td>13 [7]</td><td>15 [3]</td><td>23 [4]</td><td>-</td>

<td>Test Charpy'ego 23 C</td><td>kJ/m²</td><td>19 [0.5]</td><td>19.6</td><td>16.7 [0.4]</td><td>29 [0.5]</td><td>18 [0.3]</td><td>19 [0.4]</td><td>15.2 [0.3]</td><td>22.9 [0.4]</td>

<td>TwardoShore</td><td>-</td><td>67 [0.3]</td><td>68.6 [0.3]</td><td>68.5 [0.7]</td><td>69.5 [0.7]</td><td>67 [0.5]</td><td>68 [0.4]</td><td></td><td></td>

<td>Abrasion (ISO 4649)</td><td>%</td><td>16.6</td><td></td><td></td><td></td><td>19.4</td><td>18.7</td><td>19.4</td><td></td>

<td>Scratch resistance</td><td>um</td><td></td><td>12</td><td>13</td><td>10</td><td></td><td></td><td>13</td><td></td>

<td>Charpy test -20 C</td><td>kJ / m²</td><td></td><td></td><td>15</td><td>20</td><td></td><td></td><td>13</td><td></td>

* All samples show brittle fracture in the FNCT test

- EP 2809717

The final polymers of examples 1-4 and C1-C4 had very similar or identical densities and very similar MFR5 values, which means that they also have very similar stiffness and the possibility of practical extrusion processing. As a result, they can be compared.

It is surprising that the polyethylene blends of the invention have much higher FNCT scores than any comparable polyethylene blend. It surprises that FNCT is higher for the polyethylene composition of the invention, which contains a smaller amount of a second higher molecular weight ethylene copolymer than the one with a higher content thereof. This is also shown in Figure 2.

What even more surprising the Charpy test result indicating resistance to RCP was not reduced, as it usually happens when modifying the polymer, which raises its FNCT. This is shown in Figures 3 and 4. Both the Charpy test result at room temperature (Figure 3) and at low temperature (Figure 4) were better for a polyethylene composition having a lower content of a second higher molecular weight ethylene copolymer than the same with a higher molecular weight. its contents.

Furthermore, the scratch resistance was better (lower values) for a polyethylene containing a lower second ethylene copolymer with a higher molecular weight than the one with a higher molecular weight. This is shown in Figure 5. Also the abrasion resistance was better (lower values) for a polyethylene composition containing a lower amount of a second higher molecular weight ethylene copolymer than for the same with a higher molecular weight. This is shown in Figure 6. Even the Shore hardness has been preserved, despite the fact that the third component / fraction is, due to its high comonomer content, a relatively soft component. This is shown in Figure 7.

It is impressive that such a significant improvement in mechanical properties, and more specifically SCG and RCP, can be achieved by introducing such small amounts of a second higher molecular weight ethylene copolymer. What's even more desirable test results (Shore hardness, abrasion resistance and scratch resistance) show that the polyethylene included in the invention is more resistant to scratching, hollowing or scratching that can occur when moving pipes in the field, which means the number and size of defects, which can grow into cracks, is also lower. The combination of these features is highly desirable in the production of pipes, especially those for high-pressure applications.

We assume that the third polymer, with a relatively high molecular weight and high comonomer content, increases the degree of connections and interlacings in the polyethylene composition. This higher level of chains of interrelationships and interlacings equally distributes energy in the area of ​​the initiated crack and reduces the likelihood of crack expansion. Moreover, the polymer of the invention is also easy to prepare. A relatively small amount of the second higher molecular weight ethylene copolymer can be made in a relatively small reactor in a short time or alternatively in a medium sized reactor using very mild reaction conditions.

PPAW SO "ATENTOWA" BELLEPAT "OFFICE

Izabela Szychnlska-Hawranek ul. Słowackiego 44, 37-700 Przfit.śl tel. (016) 702-37-77 fax: (016) 675-02-87 mobile phone (0608) 503-081 e-maii <a href="mailto:fcellepat@op.pl">fcellepat@op.pl</a> NIP: 795-207-16-72 REGON: 1803505: 6

Proxy:

<img file="PL2809717T3_D0003.tif" />

- EP 2809717