Increase of homogeneity of polyethylene mixtures

FIELD: chemistry.

SUBSTANCE: invention relates to a method of increasing homogeneity of mixtures of polyethylene, intended for manufacturing moulded products, films, tubes, wires and cables. A mixture of polyethylenes contains three fractures (A), (B) and (C) of a homo- or a copolymer of ethylene and at least one comonomer C3-C10 with different molecular weights. The low-molecular fraction A) has the weight-average molecular weight Mw lower than 40 kg/mol, the highly-molecular fraction B) has the molecular weight Mw higher than 250 kg/mol and the fraction C) has the intermediate molecular weight with the weight-average molecular weight Mw from 100 to 200 kg/mol. The mixture of polyethylenes has a single peak of melting as determined by means of differential scanning calorimetry (DSC).

EFFECT: obtained mixtures of polyethylenes, due to the improved homogeneity, possess improved properties, in particular surface properties, good processability and good mechanical properties.

16 cl, 9 dwg, 4 tbl, 3 ex

 

The technical field

The present invention relates to a method for improving the homogeneity of mixtures of polyethylenes. The invention also relates to mixtures of polyethylene with improved homogeneity, in particular, to a mixture comprising three fractions of polymers of ethylene with different molecular weights. Such mixtures are in particular suitable for the manufacture of tubes, molded parts, wires and cables.

Plastic mixtures and compositions, in which different polymers are mixed to combine the positive properties of each polymer component (i.e., impact strength, rigidity, chemical resistance and so on), are widely used in many applications such as the manufacture of pipes and films.

Polyethylene with high molecular weight have improved mechanical properties compared to their counterparts with low molecular weight. However, with increasing molecular weight, the machinability of the polymer is usually reduced. Providing a mixture of polymers with high molecular weight and low molecular weight, it is possible to retain their high molecular weight polymer properties and machinability, in particular, extraterrest (low molecular weight component) can be improved.

Unfortunately, such a bimodal polymers comprising more than one polymer fractions with different molekulyarnoi mass, for example, low molecular weight (NM) fraction and a high molecular weight (VM) fraction, lack of homogeneity, which is known to be a key property. For example, a low degree of homogeneity affects the surface properties and other properties of the polymeric composition. To obtain a sufficient degree of homogeneity, mixing different fractions in the composition should be provided at the microscopic level.

When mixed bimodal polymer composition, for example, to get the pipes in mixed material often contains the so-called "white spots". These white spots are usually the same size from less than 10 to about 50 microns and are composed of particles of polymer with high molecular weight that are not mixed in the composition. Moreover, in the preparation by mixing the polymer compositions, for example, to obtain films, often appear the gel particles size of from about 0.01 to 1 mm, the particles of the gel, also consisting of particles of high-molecular polymer, not mixed and are seen as distorting discontinuities in the finished film. In addition, heterogeneity in the bimodal polymer compositions can also cause warping of the surface of products derived from them.

It is known that the uniformity of the bimodal polymer compositions can the be improved by multiple execution stages of mixing and/or establish certain conditions of mixing for polymers, coming out of the reactor. These measures, however, have the disadvantage that they are associated with a significant increase in the cost of production of the compositions.

The phase behavior in mixtures of polyethylenes (PE), notable for its crystallinity, has been studied intensively and has published a large number of works in this area. The basic rule is that in mixtures with a low content of VM faction detect signs of segregation phases. The actual limits of the Miscibility depends on extrusion equipment and conditions, as well as from the basic component properties (molecular weight and content of the co monomer).

For example, Krishnaswamy and Yang (Polymer, 48, 2007, 5348-5354) studied the occurrence of segregation phases for extruded from the melt mixtures of homopolymers of ethylene, obtained in the presence of CCPM (catalyst with a single center of polymerization on the metal). Segregation of phases was observed for mixtures with a low content of VM faction. It was found that the limits of segregation phases depend on the molecular weight VM fractions: less than the molecular mass of the VM, the wider the interval Miscibility. For example, it was found that a mixture of<40% VM (Mw ~ 350 kg/mol) are not miscible (molecular weight NM was 37 kg/mol). As a result, there is a relatively small working range, which in the present invention are trying to expand.

Thus, the aim of the present invention is the provision of compounds, including high molecular weight (VM) fraction and a low molecular weight (NM) fraction with improved uniformity. These are a mixture of polyethylene with improved homogeneity, have improved properties, in particular surface properties. At the same time, the mixture should have good machinability and good mechanical properties. Thus, another aim of the present invention is a method of expansion of the interval Miscibility when mixing high molecular weight (VM) fractions and low molecular weight (NM) fraction.

It has been unexpectedly discovered that these objectives can be achieved by adding fractions with intermediate molecular weight in the mixture of high molecular weight (VM) fractions and low molecular weight (NM) fraction.

Thus, in the first embodiment of the present invention provide a mixture of polyethylenes, consisting mainly of three fractions (A), (b) and (C) Homo - or copolymer of ethylene with different molecular weights:

A) from 10 to 50 wt.% low molecular weight fractions Homo - or copolymer with a mass-average molecular mass Mwless than 40 kg/mol;

B) from 5 to 60 wt.%, preferably from 5 to 40 wt.%, high molecular weight fractions Homo - or copolymer with a mass-average molecular mass Mwb is than 250 kg/mol; and

C) from 10 to 70 wt.% faction Homo - or copolymer having an intermediate molecular weight, when the mass-average molecular weight Mw of 100 to 200 kg/mol;

the mixture of polyethylenes has a single melting peak as determined by differential scanning calorimetry (DSC).

In another embodiment of the invention provides a mixture of polyethylenes, consisting mainly of three fractions (A), (b) and (C) Homo - or copolymer of ethylene with different molecular weights:

A) from 10 to 50 wt.% low molecular weight fractions Homo - or copolymer with a mass-average molecular weight Mw of less than 40 kg/mol;

B) from 5 to 40 wt.% high molecular weight fractions Homo - or copolymer with a mass-average molecular weight Mw of more than 250 kg/mol and a density of more than 940 kg/m3and

C) from 10 to 70 wt.% faction Homo - or copolymer having an intermediate molecular weight, when the mass-average molecular mass Mwfrom 100 to 200 kg/mol;

the mixture of polyethylenes has a single melting peak as determined by differential scanning calorimetry (DSC).

In yet another embodiment of the present invention provide a method of improving the homogeneity of a mixture of polyethylene, comprising mixing the three fractions (A), (b) and (C) Homo - or copolymer of ethylene with different molecular weights:

A) from 10 to moss.% low molecular weight fractions Homo - or copolymer with a mass-average molecular mass M wless than 40 kg/mol;

B) from 5 to 60 wt.% high molecular weight fractions Homo - or copolymer with a mass-average molecular mass Mwmore than 250 kg/mol and

C) from 10 to 70 wt.% faction Homo - or copolymer having an intermediate molecular weight, when the mass-average molecular weight Mw of 100 to 200 kg/mol,

the mixture of polyethylenes has a single melting peak as determined by differential scanning calorimetry (DSC).

In yet another embodiment of the present invention provide a way to extend the range of Miscibility for mixing the low molecular weight fraction (A) Homo - or copolymer with a mass-average molecular mass Mwless than 40 kg/mol and a high molecular weight fraction (B) Homo - or copolymer with a mass-average molecular mass Mwmore than 250 kg/mol by adding a fraction (C) Homo - or copolymer having an intermediate molecular weight, when the mass-average molecular weight Mw of 100 to 200 kg/mol,

obtaining a mixture of polyethylene comprising from 10 to 50 wt.% fraction (A), from 5 to 60 wt.% fraction (b) and from 10 to 70 wt.% fraction (C), and the mixture of polyethylenes has a single melting peak as determined by differential scanning calorimetry (DSC).

From the point of view of another aspect of the invention provides a composition including from the ect, defined above.

From the point of view of another aspect of the invention provides a product comprising a mixture as defined above, for example, film, molded product, wire, cable or pipe.

From the point of view of another aspect of the invention provides a method of obtaining a mixture of polyethylene defined above, comprising mixing:

A) from 10 to 50 wt.% low molecular weight fractions Homo - or copolymer with a mass-average molecular mass Mwless than 40 kg/mol;

B) from 5 to 60 wt.% high molecular weight fractions Homo - or copolymer with a mass-average molecular mass Mwmore than 250 kg/mol and

C) from 10 to 70 wt.% faction Homo - or copolymer having an intermediate molecular weight, when the mass-average molecular mass Mwfrom 100 to 200 kg/mol, with a mixture of polyethylenes having a single melting peak as determined by differential scanning calorimetry (DSC).

From the point of view of another aspect of the invention, provide a mixture of polyethylenes, mainly consisting of three fractions (A), (b) and (C) Homo - or copolymer of ethylene with different molecular weights:

A) from 10 to 50 wt.% low molecular weight fractions Homo - or copolymer with a mass-average molecular mass Mwless than 40 kg/mol;

B) from 5 to 60 wt.%, preferably from 5 to 40 wt.%, macromolecular coat the AI Homo - or copolymer, with the TPP190/21less than 10 g/10 min, and

C) from 10 to 70 wt.% faction Homo - or copolymer having an intermediate molecular weight and greater PTR190/21than fraction (B) comprising from 5 to 50 g/10 min;

the mixture of polyethylenes has a single melting peak as determined by differential scanning calorimetry (DSC).

Detailed description of the invention

Throughout the description the term "molecular weight" means a mass-average molecular weight.

Fraction (A), (b) and (C) is the set of polyolefin components in a mixture of polyethylene according to the invention. On this basis, the combination of components a, b and C (without any other additional components, such as additives) is called the basic resin. The total mass percentage of fractions a, b and C in the main resin should comprise up to 100 wt.%.

The mixture according to the invention may consist of specified resin base or mainly to consist of specified resin base (i.e. components are present only the main resin and the possible additives). Any quantity above or below, in relation to the properties of the mixture are also valid for the main resin. If additives are present, the mixture indicate with regard to additives present.

Usually the resin is less the th least 90 wt.% from the total mass of the mixture, preferably, at least 95 wt.%.

The mixture according to the invention can contain conventional additives, which are used with polyolefins, such as pigments (e.g. carbon black), stabilizers (antioxidants), antacids and/or substances that prevent UV radiation, antistatic agents and excipients (such as processing AIDS). Thus, the mixture according to the invention contains three fractions and optionally one or more additives. This means in used here, the phrase "mainly composed of". Preferably, the amount of these additives is 10 wt.% or less, more preferably 8 wt.% or less by weight of the mixture.

Preferably, the mixture comprises carbon black in the amount of 8 wt.% or less, more preferably, from 1 to 4 wt.%, from the total mass of the mixture.

More preferably, the amount of additives other than carbon black is 1 wt.% or less, more preferably 0.5 wt.% or less.

The properties of each polymer fraction described in more detail below.

Fraction (A)

Fraction (A) is a low molecular weight (NM) fraction (A) Homo - or copolymer with a mass-average molecular mass Mwless than 40 kg/mol. The lower limit of Mw NM fraction is preferably 1 kg/mol. Preferably, NM fraction (A) has a mass-average molecular weight of from 15 to 4 kg/mol, more preferably, from 20 to 30 kg/mol.

PTR190/2fraction (A), measured according to ISO 1133, is preferably at least 50 g/10 min, more preferably at least 100 g/10 min, the Upper limit for the TPP2NM fraction is preferably 1000 g/10 minutes

In one of the embodiments, for example, when NM component is homopolymer, the density of fraction (A), measured according to ISO 1183 at 23°C is more than 940 kg/m3preferably, from 940 to 975 kg/m3. Alternatively, preferably it is between 955 and 975 kg/m3more preferably, from 965 to 975 kg/m3.

In another embodiment, for example, when NM component is a copolymer, the density of fraction (A), measured according to ISO 1183 at 23°C is less than 940 kg/m3preferably from 910 to 935 kg/m3.

The term "ethylene copolymer", as used here, covers the polymers comprising repeating units of ethylene and at least one of the co monomer With3-C10. Preferably, the copolymers are binary and therefore include ethylene and the only comonomer.

The comonomers that may be used include alpha-olefins With3-C10, preferably selected from but-1-ene, Gex-1-ene, 4-methyl-Penta-1-ene, hept-1-ene, about the t-1-ene and Oct-1-ene, more preferably, the buta-1-ene and Gex-1-ene. Preferably use hexene or butene, or a mixture of hexene and butene. In one of the embodiments of the invention use only one comonomer. Comonomer represents, for example, hexene or butene, preferably hexene.

Preferably, the ethylene copolymers contain from 1 to 15 wt.% the co monomer, based on the weight of high molecular weight ethylene fraction, preferably from 2 to 12 wt.% and, more preferably, from 5 to 10 wt.%.

The term "homopolymer" as used here encompasses polymers, mainly consisting of repeating units of ethylene. The homopolymers, for example, may include at least 99.8 wt.%, preferably, at least 99.9 wt.% repeating units of ethylene. More preferably, homopolymers serves to detect only the links of ethylene.

Preferably NM fraction (A) is a copolymer, more preferably a copolymer of ethylene and hexene.

Fraction (In)

Fraction (B) is a high molecular weight (VM) fraction Homo - or copolymer with a mass-average molecular mass Mwmore than 250 kg/mol, preferably more than 280 kg/mol. The upper limit of Mw VM fraction is preferably 500 kg/mol. In one of the embodiments of the mass-average molecular mass Mwfraction (C) may be bolee kg/mol.

PTR190/2fraction (C), measured in accordance with ISO 1133, preferably less than 1 g/10 min, more preferably less than 0.5 g/10 min and, more preferably, less than 0.1 g/10 minutes

PTR190/21fraction (C), measured in accordance with ISO 1133, preferably less than 10 g/10 min, more preferably less than 5 g/10 min and, more preferably, less than 1 g/10 minutes

VM density fraction, measured according to ISO 1183 at 23°C, ranges from 900 to 970 kg/m3preferably, from 920 to 960 kg/m3especially preferably, from 940 to 950 kg/m3.The density may be more than 940 kg/m3.

The terms "copolymer" and "homopolymer" is defined as described above. Preferably VM fraction (B) is a homopolymer.

Fraction (C)

Fraction (C) represents the fraction of Homo - or copolymer having an intermediate molecular mass (PMM), when the mass-average molecular mass Mwfrom 100 to 200 kg/mol, preferably from 110 to 180 kg/mol, more preferably from 120 to 160 kg/mol. In one of the embodiments of the mass-average molecular mass Mwfraction (S) can range from 70 to 200 kg/mol.

Fraction (C) preferably has a MFR190/2less than 10 g/10 min, preferably less than 5 g/10 min and, more preferably, less than 1 g/10 min MFR190/2and/or PTR190/2 faction (S) must be less than fraction (A), but more than fraction (B). Fraction (C) preferably has a MFR190/21from 5 to 50 g/10 min, preferably from 10 to 20 g/10 minutes

Density PMM fraction, measured according to ISO 1183 at 23°C, ranges from 920 to 970 kg/m3preferably, from 940 to 960 kg/m3.

The terms "copolymer" and "homopolymer" is defined as described above. Preferably PMM fraction (C) is a homopolymer.

The amount of each fraction

Preferably a low molecular weight fraction (A) is the largest number in the mixture. Thus, the mass percentage or fraction (B) or fraction (S) (or both) should preferably exceed the mass percentage of fraction (A). Preferably the weight percent content of fraction (B) is greater than or equal percentage mass content of fraction (A).

Preferably, each component must be at least 15 wt.% a mixture of, for example, more than 15 wt.%, or 16 wt.%, preferably at least 18 wt.%. In particular, preferably fraction (b) is at least 18 wt.% of the mixture.

Preferably, fraction (a) is from 15 to 45 wt.%, more preferably, from 20 to 40 wt.%.

Most preferably the VM fraction is less than 30 wt.% of the total m the ssy mixture, preferably, less than 25 wt.%. Preferably it ranges from 10 to 20 wt.% or from 15 to 25 wt.%.

The fraction (S) can range from 15 to 65 wt.%, preferably, from 20 to 60 wt.%, particularly preferably, from 20 to 40 wt.%.

Mixture

As noted above, the mixture according to the invention is obtained from a separate fractions (A), (b) and (C) (in addition to the standard additives). The mixture can have a density from 920 to 970 kg/m3preferably, from 930 to 960 kg/m3.

The mixture may also have PTR2from 0.1 to 5 g/10 min, preferably from 0.1 to 3 g/10 minutes

The combination of these three components gives a mixture of improved uniformity. Thus, the homogeneity of the mixture containing the NM fraction (a) and VM fraction (B), increase by adding PMM faction (S).

In accordance with the second embodiment, the interval Miscibility for mixing NM fraction (A) with VM fraction (C) expand by adding PMM fraction (C). Interval Miscibility means that the ranges of the percentage, which can be obtained from this mixture, increase, using the PMM component, as proposed in this application.

The main analytical method used to determine the Miscibility is DSK. If two components are mixed is not homogenous, the mixture typically shows two melting temperature corresponding to the melting temperature of each to mponent. Thus, in a binary mixture of BM and NM component is often a situation when the mixture shows a melting temperature corresponding to each faction, due to the heterogeneous nature of the mixture.

When there is only one peak crystallization during solidification and you receive a single melting peak (usually between the melting temperature of the components), as increasing the temperature of the crystallized mixture, the mixture is mixed. Not limited to any theory, I believe that during the crystallization of two components form a joint crystals, which inevitably leads to a single melting point. Therefore, the mixture according to the invention is designed in such a way that shows a single melting point in DSC.

The resulting mixture is defined as having only one visible melting temperature. For the purposes of the invention, the presence of only one significant melting temperature means that the DSC there are no other peaks with an intensity of more than 10% from the main melting peak, preferably more than 5%. The intensity of the peaks of melting, if they occur, identify known DSK ways, as described in the examples below. In particular, the intensity of the main and any secondary peaks in the DSC to determine the heat of fusion, integrated vannoy ranges separate melting peaks.

Preferably the mixture has only one melting point, and other melting temperature is generally indistinguishable.

It is also preferred mixture according to the invention show only one peak crystallization, indicating the existence of one type of crystalline compounds upon cooling. It is therefore evident that crystallize. The preferred melting point, MP, gradually increases from 127,0 to 134,1°C with the increase of the content of the VM component. This shows that the mixture is very similar to the one-component system. Therefore, preferably the melting point of the mixture ranges from 127 to 135°C.

An additional characteristic of the invention consists in that for the determination of heterogeneity do not use rheological characteristics. It was unexpectedly found that it is better to use DSC in the identification of heterogeneous mixtures than rheological measurements.

Getting

Here, where the numerical values of the properties of fractions (A), (b) and (C) mixtures of the present invention, these values are generally applicable to cases where they can directly measure on the corresponding fractions, for example, when the fraction is obtained separately or get the first stage of the multistage method.

However, the basic resin also can be obtained by a multi-stage manner, and before occhialino it get this way in which, for example, fraction (A), (b) and (C) receive on successive stages. In this case, the properties of the fractions obtained at the second and third stage (or later stages) multi-stage method, it is possible to predict from the properties of the polymers, which separately receive in one stage using the same polymerization conditions (e.g., the same temperature, partial pressure of reagents/solvents, suspension medium, reaction time), as in the stage of multi-stage method, which receives a fraction, and using a catalyst, which is not present previously obtained polymer. Alternatively, the properties of the fractions obtained at a later stage of the multistage method, can also be calculated, for example, in accordance with C. Hagstrom, Conference on Polymer Processing The Polymer Processing Society), Extended Abstracts and Final Programme, Gothenburg, August 19-21,1997, 4:13.

Thus, although the products can not be directly measured in a multistage manner, the properties of the fractions obtained in the later stages of this multi-stage method, can be determined using one of the above methods, or both. Specialist in the art can choose the appropriate method.

The method by which to obtain a plastic mixture for molding according to the invention is the substantial in the present invention. The mixture can be obtained by mechanical mixing of the individual fractions in the reactor or mixing in situ, or by combining these two methods, or other methods that achieve the desired uniformity.

For example, the mixture can be obtained by mechanical mixing of the three factions in the required quantity, for example, using traditional devices for mixing or homogenization, such as a Bunbury mixer, a double-roll mill for rubber kneading machine Buss or twin screw extruder. In this case it is necessary to achieve the desired uniformity.

Fraction (A), (b) and (C) for mechanical mixing of prepared separately by any appropriate conventional method Homo-copolymerization of ethylene, for example, in the gas phase, slurry phase, liquid phase (polymerization volume), using conventional reactors, such as a loop reactor, gas-phase reactor, semi-continuous reactor or a batch reactor, the steps in the presence of a catalyst of polymerization. Preferably, the faction get in a suspension reactor, preferably a loop reactor or in a gas-phase reactor.

The composition can also be obtained by mixing in situ at least two of the three factions or all three factions. Getting on multimodal is the iMER by mixing in situ implies obtaining fractions simultaneously in one reaction stage (for example, using different catalysts) and/or the receipt of these fractions multistage method.

Multistage method is defined as the method of polymerization in which a polymer comprising two or more fractions, receive by obtaining each or at least two fractions of the polymer in a separate reaction stage, usually under different reaction conditions at each stage, in the presence of the reaction product of the previous step, which includes the catalyst for polymerization. The polymerization reaction used at each stage may include traditional reaction homopolymerization or copolymerization of ethylene, for example, in the gas phase, slurry phase, liquid phase polymerization using conventional reactors, e.g. loop reactors, gas phase reactors, reactors with mechanical stirring, the reactor periodic action (see, for example, W97/44371 and W96/18662).

Thus, the multimodal polyethylene mixture for molding according to the invention can be obtained in the multi-stage sequence of reactions involving successive stages of polymerization carried out in predetermined different reaction conditions in the respective reactors arranged in series, with the obtainment of polyethylene fractions with the primary molecular weight. A method of this type can be carried out in a suspension medium: in this case, the first polimerizuet monomers and the regulator molar mass, preferably hydrogen, in a first reactor under first reaction conditions in the presence of a suspension medium and a suitable catalyst, then move to the second reactor and polymerized under second reaction conditions and then move to the third reactor and will also polimerizuet when the third reaction conditions, and the first reaction conditions differ from the second and third reaction conditions, resulting in three polyethylene fractions with different molecular weights.

Each method of obtaining the use of the catalyst for polymerization. Polymerization catalysts include coordination catalysts based on transition metal, such as catalysts of the Ziegler-Natta (TSN), metallocene, not metallocene catalysts, Cr-catalysts etc., the Catalyst may be applied, for example, on traditional media, such as silicon dioxide, Al-containing media, and media-based magnesium dichloride.

The preferred catalyst is a metallocene catalyst. Getting a metallocene catalyst can be made according or analogously to methods known from the literature and familiar to specialists in the area and equipment.

These metallocene bear at least one organic ligand, generally 1, 2 or 3, for example, 1 or 2, which has η-bond with the metal, for example, η2-6- ligand, such as η5the ligand. Preferably metallocene contains transition metal 4-6 groups, are suitable titanate, zirconate or garrote that contain at least one η5-ligand, for example, possibly substituted cyclopentadienyl, possibly substituted indenyl, possibly substituted tetrahydroindene or possibly substituted fluorenyl.

The metallocene compound may have the formula I:

where each Ls is independently represents an unsubstituted or substituted and/or condensed Homo - or heterosynaptically ligand, for example, substituted or unsubstituted cyclopentadienyls, substituted or unsubstituted intenally, or substituted or unsubstituted fluorenyl ligand; and one or more substituents preferably selected from a halogen, a hydrocarbon radical (e.g., With1-C20of alkyl, C2-C20alkenyl,2-C20the quinil,3-C12cycloalkyl,6-C20aryl or7-C20arylalkyl)3-C12cycloalkyl, which contains 1, 2, 3 or 4 heteroatoms in the ring fragm is NTE, With6-C20- heteroaryl,1-C20haloalkyl, -SiR"3, -OSiR", -SR", -PR"2or-NR2where each R" is independently hydrogen or a hydrocarbon radical, for example, With1-C20the alkyl, C2-C20alkenyl,2-C20the quinil,3-C12cycloalkyl or6-C20by aryl, or for example, in the case of-NR2two Deputy R" can form a ring, e.g. five - or six-membered ring together with the nitrogen atom to which they are attached.

T is a bridge of 1-7 atoms, e.g. a bridge of 1-4 C-atoms and 0-4 heteroatoms, where the heteroatom(s) may(may) be represented, for example, the atom(s) Si, Ge and/or O, and each of the atoms of the bridge may independently bear substituents, such as C1-C20alkyl, three(C1-C20alkyl)silyl, three(C1-C20alkyl)siloxane or6-C20aryl substituents, or a bridge of 1-3, e.g. one or two, heteroatoms, such as atom(s) of silicon, germanium and/or oxygen, for example, -SiR12where each R1independently represents a C1-C20alkyl, C6-C20aryl or three(C1-C20alkyl)silyl residue, for example, trimethylsilyloxy the rest.

M is a transition metal 4-6 groups, for example, 4 g of uppy, for example, Ti, Zr or Hf.

Each And independently represents a Sigma-ligand, such as H, halogen, C1-C20alkyl, C1-C20alkoxyl,2-C20alkenyl,2-C20quinil,3-C12cycloalkyl,6-C20aryl, C6-C20aryloxy,7-C20arylalkyl,7-C20arylalkyl, -CH2-Y, where Y represents a C6-C20aryl, C6-C20heteroaryl,1-C20alkoxyl,6-C20aryloxy, -NR2, -SiR"3or-OSiR"3, -SR",-PR"3, -OSiR"3or-NR2and each R" is independently hydrogen or a hydrocarbon radical, for example, With1-C20the alkyl, C2-C20alkenyl,2-C20the quinil, C3-C12cycloalkyl or6-C20by aryl, or for example, if NR2two Deputy R" can form a ring, e.g. five - or six-membered ring together with the nitrogen atom to which they are attached.

Each of the above ring fragments separately, or as part of a selection as Deputy for Cf, A, R" R' can also be substituted, for example, With1-C20the alkyl which may contain Si atoms and/or;

N is 0,1 or 2, for example 0 or 1,

m is 1, 2 or 3, for example 1 or 2,

q is 1, 2 or 3, nab the emer 2 or 3, where m+q is equal to the valency M

More preferably metallocene compound of formula II:

where both Cf represent substituted and condensed Homo-or heterosynaptically ligands; M is Zr or Hf;

and both X represents-CH2-Y, where Y is a C6-20the aryl, C6-20heteroaryl,1-20alkoxyl,6-20alloxylon, -NR2, -SiR"3or-OSiR"3and R" represents a hydrocarbon radical With1-20or, in the case of-NR2two of the substituent R may form a ring together with the nitrogen atom to which they are attached.

In the formula (II) both Cf are possibly substituted, or possibly condensed Homo - or heterosynaptically ligands, for example, substituted or unsubstituted cyclopentadienyls, substituted or unsubstituted intenally, or substituted or unsubstituted fluorenyl ligand.

These possible substituents present in the Cf group selected from a halogen, a hydrocarbon radical (e.g., With1-20of alkyl, C2-20alkenyl,2-20the quinil,3-12cycloalkyl,6-20aryl or7-20arylalkyl)3-12geterotsiklicheskie,5-20heteroaryl,1-20haloalkyl, -NR'2, -SiR'3or-OSiR'3and R' submitted is a hydrocarbon radical With 1-20(for example, C1-20alkyl, C2-20alkenyl,2-20quinil,3-12cycloalkyl or6-20aryl), or in the case of-NR'2two of the substituent R' may form a ring together with the nitrogen atom to which they are attached.

Cf means preferably cyclopentadienyl, indenyl, tetrahydroindene or fluorenyl, possibly substituted, as defined above. More preferably Cf means cyclopentadienyl or tetrahydroindene.

In the preferred embodiment both Cf groups are unsubstituted, or both groups substituted by the same number and kind of substituents.

Preferred substituents include1-20alkyl, C6-20aryl or7-20arylalkyl.

Especially preferred Cf groups are unsubstituted or both are1-6alkyl substituents such as methyl, ethyl, isopropyl or n-butyl.

M is Zr or Hf, particularly preferably Hf.

Preferably both Y are selected from C6th aryl, -NR2, -SiR"3or-OsiR"3where R is defined as above.

More preferably-CH2-Y is benzyl or-CH2-SiR"3where R" is C1-6the alkyl or C6-20the aryl.

Especially preferred are the following compounds:

bis(n-butylcyclopentadienyl)Hf dibenzyl,

bis(methylcyclopentadienyl)Hf is benzyl,

bis(1,2-dimethylcyclopentane)Hf dibenzyl,

bis(n-propylcyclopentanol)Hf dibenzyl,

bis(isopropylcyclopentadienyl)Hf dibenzyl,

bis(1,2,4-trimethylcyclopentanone)Zr dibenzyl,

bis(tetrahydroindene)Zr dibenzyl,

bis(n-butylcyclopentadienyl)Hf (CH2SiMe3)2,

bis(n-propylcyclopentanol)Hf (CH2SiMe3)2,

bis(isopropylcyclopentadienyl)Hf (CH2SiMe3)2,

bis(1,2,4-trimethylcyclopentanone)Zr (CHrSiMe3)2.

Most preferred is bis(n-butylcyclopentadienyl)Hf dibenzyl.

Getting metallocenes used in accordance with the invention can be carried out according to or analogously to methods known from the literature and familiar to specialists in the field of technology.

Metallocene compounds of the formula I can be obtained, for example as described in EP 1462464.

The composition of the catalyst is preferably used in the invention also includes soaked alumoxanes media received at the contact alumoxane or modified alumoxane with silicon dioxide as the inert material of the carrier. There are many ways to get alumoxane or modified alumoxane, non-limiting examples of which are described in patents US№№4665208, 4952540, 5091352, 5206199, 5204419, 4874734, 4924018,4908463, 4968827, 5308815, 5329032, 5248801, 5235081, 5157137, 5103031, 5391793, 5391529, 5693838, 5731253, 5731451, 5744656 and in EP-A-0561476, EP-B1-0279586 and EP-A-0594218, and in WO 94/10180, all of these documents are fully incorporated into this application by reference.

Preferably for impregnation of the carrier used alumoxane, in particular, methylalumoxane or modified methylalumoxane, isobutyryloxy, for example, TIBAO (tetraisostearate) or GIBO (examsolutions).

More preferably used methylalumoxane (MAO).

The molar ratio of AI alumoxane component to the metal of the catalyst with a single center of polymerization on the metal is from 0.3:1 to 2000:1, preferably from 20:1 to 800:1 and, most preferably, from 50:1 to 500:1.

Preferred as the inert carrier used silicon dioxide. Surface area, pore volume and particle size of the silica can be selected in accordance with the requirements of the particular polymerization process, in which the use of this catalyst. Usually use particles of silicon dioxide having a surface area from about 10 to about 700 m2/g (defined by BET method), pore volume from about 0.1 to about 6.0 cm3/g and average particle size from about 10 to about 500 microns. Silicon dioxide can be granulated, agglomerated, to loadnum or in another form.

In addition, preferably the material of the carrier calicivirus, i.e., subjected to heat treatment in air and then in the presence of an inactive gas, such as nitrogen. This heat treatment is preferably carried out at a temperature above 100°C , more preferably at 200°C or higher, for example 200-800°C, in particular approximately 600°C. Processing the calcination is preferably carried out in a few hours, for example from 2 to 30 hours, more preferably, about 10 o'clock

Soaked alumoxanes media get in contact alumoxane with silicon dioxide and heated to a temperature from 50°C to 100°C. This silicon dioxide containing alumoxane use as a carrier for metallocene formula (I) or (II). Preferably impregnated alumoxanes media contains less than 15.0 wt.% aluminum, more preferably from 9.0 to 14.5 wt.% and, most preferably, from 10.0 to 14.0 wt.% aluminum based on the total mass of material media and alumoxane.

The catalyst is preferably applied to the material of the carrier in an amount of from 0.05 to 4 wt.%, preferably, from 0.1 to 3.0 wt.%, particularly preferably, from 0.2 to 2.0 wt.% the active metal is relatively dry mass of the material medium.

Applications

The mixture according to the invention can be used for pipes or other products, such as the film or molded product. Importantly, the invention allows to add a small amount of VM component in the mixture. This component contributes to improved resistance to cracking under stress environment, and in the implementation of the invention this can be achieved without any inhomogeneities in the mixture.

Such mixtures, in particular, suitable for receiving the pipe, in the manufacture of products by molding, and in the manufacture of wires and cables.

The invention is hereinafter described in connection with the following non-limiting examples and drawings.

Brief description of drawings

In Fig.1 shows a micrograph of a mixture of N-30, showing the segregation phases.

In Fig.2 presents two peaks on the curve for the mixture N-30.

In Fig.3 shows a micrograph of the mixture 2.

In Fig.4 shows a DSC mixture 2, which shows a single peak on the curve.

In Fig.5 shows a micrograph of the mixture 3.

In Fig.6 shows the DSC mixture 3, which shows a distinct shoulder on the curve.

In Fig.7 shows a micrograph of the mixture 4.

In Fig.8 shows the DSC mixture 4, which shows a single peak on the curve.

In Fig.9 shows the configuration of the screw co-rotating twin screw extruder used in the mixing.

Experimental studies and examples 1. Definitions and methods of measurement of GPC: average molecular mass, the mole is warno mass distribution and the rate of polydispersity (Mn, Mw, DFID, TTD)

Average molecular weight (Mn, Mw), molecular weight distribution (RMP) and its width, the described indicator of polydispersity TTD=Mn/Mw (where Mn- srednekislye molecular mass Mw- mass-average molecular weight) were determined using gel chromatography (GPC) in accordance with ISO 16014-4:2003 and ASTM D 6474-99. Device for GPC Waters GPCV2000 equipped with differential Refractometer and a built-in type viscometer, used with columns 2 GMHXL-HT and 1x G7000HXL-HT TSK-gel, manufactured by Tosoh Bioscience and used 1,2,4-trichloranisole (TCB, stabilized with 250 mg/l 2,6-ditretbutyl-4-METHYLPHENOL) as solvent, at a temperature of 140°C and at a constant flow rate of 1 ml/min of 209.5 ml of sample solution was injected for the study. Columns were calibrated using a standard calibration (in accordance with ISO 16014-2:2003) at least 15 polystyrene (PS) standards with a narrow MMD, from 1 kg/mol to 12000 kg/mol. Used constants Brand-Houwink for PS, PE and PP according to the standard ASTM D 6474-99. All samples were prepared by dissolving (140°C) 0.5 to 4.0 mg of polymer in 4 ml of stabilized TCB (the same as the mobile phase) and was kept for a maximum of 3 h at a maximum temperature of 160°C under continuous light shake before selection of the sample into the instrument for GPC.

PL is tnost polymer was determined in accordance with ISO 1183-1987, method D, on samples obtained by pressing.

The melt flow index of

The melt flow index (MFR) determined according to ISO 1133 and is expressed in g/10 min MFR is an indicator of fluidity and, therefore, the workability of the polymer. The higher the melt flow index, the lower the viscosity of the polymer, MFR is determined at a temperature of 190°C, and it can be defined at different loads, for example, of 2.16 kg (MFR190/2), 5 kg (MFR190/5) or 21.6 kg (MFR190/21).

The content of the co monomer in the obtained products were measured in a known manner based on infrared spectroscopy with Fourier transform (ICSPP) calibrated with 13C-NMR, IR spectrometer Nicolet Magna 550 together with the software Nicolet Omnic FTIR.

Of the samples received film thickness of from about 220 to 250 μm by means of pressing. Such films were made from the calibration samples with known content of co monomer. Measured the thickness of at least five points of the film. Then the film was polished with sandpaper to eliminate reflections. The film did not touch hands to avoid contamination. For each sample and the calibration sample prepared at least two films. Film extruded from the pellet using the press for films Graceby Specac at a temperature of 150°C when the belt preheating 3+2 min, time pressing 1 min and a cooling time of 4 to 5 minutes For samples with very high molecular weight preheating time can be increased, or increased temperature.

The content of the co monomer was determined from the absorption at a wave number of about 1378 cm-1. Comonomer used in the calibration samples was the same as comonomer present in the samples. The study was carried out at a resolution of 2 cm-1the amplitude of the wave number of from 4000 to 400 cm-1and the number of scans 128. At least two spectra was performed according to each film.

The content of the co monomer was determined on the basis of spectrum in the wave number range from 1430 to 1100 cm-1. Absorption was measured as the peak height, choosing the so-called short or long base line or both. Short baseline was performed approximately in the range 1410-1320 cm-1through the minimum point, and the long baseline conducted from about 1410 to 1220 cm-1. Calibration should be implemented specifically for each type of baseline. It is also necessary that the content of the co monomer in the sample were within the range of concentrations of the co monomer calibration samples.

DSC

The melting temperature Tmmeasured by Mettler instrument TA for differential scanning calorimetry (the IC) on samples 3±0.5 mg, in accordance with IS0 11357-3:1999. The melting temperature obtained in the course of scanning the cooling-heating at 10°C/min from 30°C to 225°C. the melting Temperature was recorded as peaks endotherm and ectotherm.

Optical microscopy

Optical microscopy of the obtained polymer was performed using thin slices of approximately 20 microns thick.

Example 1

To determine the interval Miscibility in NM/VM mixtures received binary mixture, choosing VM fraction () of homopolymer NM and the fraction (A) of a copolymer with a high content of co monomer.

To determine the effect of the third component, received two different groups of ternary mixtures by mixing pure components, binary mixtures, above, with PMM fraction (C) of the copolymer or PMM fraction (C) of homopolymer.

2. Example 2.1: Obtain catalyst

Getting metallocene complex

The complex catalyst used in the examples of polymerization, represented bis(n-butylcyclopentadienyl)hafnium dibenzyl, (n-BuCp)2Hf(CH2Ph)2and it was received according to example 2 preparation of the catalyst described in WO 2005/002744, bis(n-butylcyclopentadienyl)hafnium dichloride (from Witco).

The receipt of the catalyst was carried out in a batch reactor, the volume of 160 l, to which was added a solution of metallocene complex. SC is the rate of mixing was 40 rpm during the reaction and 20 rpm during drying. The reactor was thoroughly washed with toluene before the reaction was purged with nitrogen after addition of silicon dioxide.

Example 2.2: a composition of catalyst

First prepare a suspension of 10.0 kg of activated silica (industrial output media from silicon dioxide, HROA, with an average particle size of 20 μm, from Grace) 21.7 kg of dry toluene at room temperature. Then the suspension of silicon dioxide was added in 14.8 kg of 30 wt.% solution methylalumoxane in tolulope (MAO, Albemarle) for 3 hours then the mixture MOA/silicon dioxide was heated to a temperature of 79°C for 6 h and then cooled to room temperature.

Carried out the reaction of the obtained solution with 0.33 kg of a solution of (n-BuCp)2Hf(CH2Ph)2in toluene (67,9 wt.%) for 8 h at room temperature.

The catalyst was dried in a stream of nitrogen for 5.5 h at 50°C. the resulting catalyst had a molar ratio Al/Hf 200, Hf concentration of 0.44 wt.% and the Al concentration of 13.2 wt.%.

3. Example 3.1: Plastic components

Obtaining fractions (A), (b) and (C) low Molecular weight fraction And a copolymer of ethylene (fraction NMWith), the fraction of Homo/copolymer with an intermediate molecular weight (fraction PMM) and high-molecular fraction homopolymer ethylene (fraction VMG) received separately in the installation, vkluchaya the reactor prior to polymerization (reactor prior to polymerization loop type by volume of 0.05 m 3and loop reactor (0.5 m3). Obtained as described above, the catalyst loaded into the reactor prior to polymerization in the form of a 15 wt.% oil suspensions (white oil PRIMOL 352). Other parameters of the reaction are shown in table 1.

Table 1
FactionNMwithPMMbPMMaVMg
The preliminary polymerization
T, °C60606060
Pressure, MPa (bar)5,8 (58)6,0 (60)5,9 (59)6,0 (60)
Catalyst loading, g/hto 19.929,731,330,9
Download antistatic agent, RRT Octastat 3000 05,005,0
Download of ethylene kg/h0202,0
Download H2, g/h0100,7
Download propane, kg/h34,34734,347,4
Loop reactor
T, °C74858585
Pressure MPa (bar)5,7 (57)5,7 (57)5,7 (57)5,6 (56)
Download of ethylene (C2), kg/h353738 34
Download H2, g/h121,81,20

FactionNMWithPMMbPMMandVMG
Download hexene (C6), kg/h5,202,30
Download propane, kg/h67826782
The concentration of C2the mole.%6,26,24,85,9
The relation of H2/S2, mol/KMOL0,50,070,090,02
Relationship With6/S2, mol/KMOL219-106 -
Capacity, kg/hthe 33.434,037,731,0
Properties
Added Irganox V, ppm)2000200020002000
PTR190/2, g/10 min3700,930,7-
PTR190/21, g min-17130,88
Density, kg/m3922955923944
Mwkg/mol24129135294
Content6, wt.%8,3-4,6-

Thus, using the Ali following materials:

td align="center"> 133,9
PTR2MwMMDTpl.With6Density
NMModal copolymer37024,0004,3118,78,3922
VMModal Homo-polymer0,042940002,4134,3-944
PMMandModal copolymer0,71350002,3119,14,6923
PMMbModal Homo-polymer0,93of 129,0002,6-955

3.2 Preparation of polyethylene mixture

These three fractions were mixed and homogenized in the melt in the extruder. A mixture was obtained by kneading in a twin screw extruder Prism TSE 16 from rotating in one direction screws which engages with a screw diameter D of 16 mm and a ratio L/D of 25, using the mixing augers high intensity with units of kneading (see Fig.9). Have established the following temperature profile along the length of the screw: 210°C/215°C/220°C/215°C/210°C, in the performance of 1-1,5 kg/h and the speed of screw rotation of 200 rpm meters Each composition was extrudible twice to ensure the required homogenization. Prepare the following mixture:

Binary mixture (comparative)

MixtureNM, wt.%VM, wt.%T melting point, °C
H-901090Not treated
N-703070132
N-5050 50129
H-307030Heterogeneous
H-109010Heterogeneous

In Fig.1 shows a micrograph N-30, illustrating the segregation phases. DSC (Fig.2) shows two peaks in the melting curve. There is a distinct shoulder at temperatures MP=108°C. This mixture is heterogeneous. As reducing the number of VM component, uniformity deteriorates.

Triple mix

MixtureNM, wt.%PMMand, wt.%PMMb, wt.%VM
wt.%
TPL, °C
1202060131
2402040128,2
3# 602020heterogeneous
4206020of 124.7
5202060133
6402040130
7#602020heterogeneous
8206020133

# comparative examples

In Fig.3 shows a micrograph of the mixture 2. DSK mix 2 (Fig.4) shows a single peak in the melting curve. This mixture is homogeneous.

In Fig.5 shows a micrograph of a mixture of 3, showing local heterogeneity. DSK mix 3 (Fig.6) shows different the chimo shoulder on the melting curve. This mixture is not homogeneous.

In Fig.7 shows a micrograph of the mixture 4. DSK mix 4 (Fig.8) shows a single peak in the melting curve. This mixture is homogeneous.

Thus, the mixtures according to the invention show a single melting point in DSC and are uniform.

1. A mixture of polyethylenes, consisting mainly of three fractions (A), (b) and (C) Homo - or copolymer of ethylene with different molecular weights:
A) from 10 to 50 wt.% low molecular weight fraction homopolymer of ethylene or copolymer of ethylene and at least one of the co monomer C3-C10with mass-average molecular mass Mwless than 40 kg/mol;
B) from 18 to 60 wt.% high molecular weight fractions homopolymer of ethylene or copolymer of ethylene and at least one of the co monomer C3-C10with mass-average molecular mass Mwmore than 250 kg/mol and
C) from 10 to 70 wt.% fraction homopolymer of ethylene or copolymer of ethylene and at least one of the co monomer C3-C10having intermediate molecular mass, with the mass-average molecular mass Mwfrom 100 to 200 kg/mol;
the mixture of polyethylenes has a single melting peak as determined by differential scanning calorimetry (DSC), with any fraction of copolymer contains from 1 to 15 wt.% the co monomer.

2. A mixture of polyethylene on the .1, consisting mainly of three fractions (A), (b) and (C) Homo - or copolymer of ethylene with different molecular weights:
A) from 10 to 50 wt.% low molecular weight fractions Homo - or copolymer with a mass-average molecular weight Mw of less than 40 kg/mol;
B) from 18 to 40 wt.% high molecular weight fractions Homo - or copolymer with a mass-average molecular mass Mwmore than 250 kg/mol and a density of more than 940 kg/m3and
C) from 10 to 70 wt.% faction Homo - or copolymer having an intermediate molecular weight, with the mass-average molecular mass Mwfrom 100 to 200 kg/mol;
the mixture of polyethylenes has a single melting peak as determined by differential scanning calorimetry (DSC).

3. A mixture of polyethylenes under item 1, comprising from 18 to 40 wt.% fraction (B), preferably from 18 to 30 wt.%.

4. A mixture of polyethylenes under item 1, in which component (B) is a homopolymer.

5. A mixture of polyethylenes under item 1, in which the mass percentage of fraction (B), fraction (s) or both of the fractions exceeds the mass percentage of fraction (A).

6. A mixture of polyethylenes under item 1, in which component (A) is a copolymer, in particular a copolymer of ethylene and hexene.

7. A mixture of polyethylenes under item 1, in which the density of fraction (C) ranges from 940 to 960 kg/m3.

8. A mixture of polyethylenes under item 1, have th the melting point of 127 to 135°C.

9. A mixture of polyethylenes under item 1, in which each faction is at least 15 wt.% of the mixture.

10. A mixture of polyethylene according to any one of the preceding paragraphs, in which the fraction (A) is a copolymer fraction (B) represents a homopolymer and a fraction (b) is at least 18 wt.% of the mixture.

11. The composition comprising the mixture according to any one of paragraphs.1-10.

12. The product made from a mixture according to any one of paragraphs.1-10, such as films, molded products, wire, cable or pipe.

13. A method of improving the homogeneity of a mixture of polyethylene, comprising mixing the three fractions (A), (b) and (C) Homo - or copolymer of ethylene with different molecular weights and copolymer comprises repeating units derived from ethylene and at least one of the co monomer C3-C10:
A) from 10 to 50 wt.% low molecular weight fraction homopolymer of ethylene or copolymer of ethylene and at least one of the co monomer C3-C10with mass-average molecular mass Mwless than 40 kg/mol;
B) from 18 to 60 wt.% high molecular weight fractions homopolymer of ethylene or copolymer of ethylene and at least one of the co monomer C3-C10with mass-average molecular mass Mwmore than 250 kg/mol and
C) from 10 to 70 wt.% fraction homopolymer of ethylene or copolymer of ethylene and at least one of the co monomer C 3-C10having intermediate molecular mass, with the mass-average molecular mass Mwfrom 100 to 200 kg/mol,
the mixture of polyethylenes has a single melting peak as determined by differential scanning calorimetry (DSC), with any fraction of copolymer contains from 1 to 15 wt.% the co monomer.

14. A way to extend the range of Miscibility for mixing the low molecular weight fraction (a) homopolymer of ethylene or copolymer of ethylene and at least one of the co monomer C3-C10with mass-average molecular mass Mwless than 40 kg/mol and a high molecular weight fraction (C) homopolymer of ethylene or copolymer of ethylene and at least one of the co monomer C3-C10with mass-average molecular mass Mwmore than 250 kg/mol, including the addition of fraction (C) of homopolymer of ethylene or copolymer of ethylene and at least one of the co monomer C3-C10having intermediate molecular mass, with the mass-average molecular mass Mwfrom 100 to 200 kg/mol, obtaining a mixture of polyethylene comprising from 10 to 50 wt.% fraction (A), from 18 to 60 wt.% fraction (b) and from 10 to 70 wt.% fraction (C), and the copolymer comprises repeating units derived from ethylene and at least one of the co monomer C3-C10and the mixture of polyethylenes them is no single melting peak, as determined by differential scanning calorimetry (DSC), with any fraction of copolymer contains from 1 to 15 wt.% the co monomer.

15. The method of obtaining a mixture of polyethylene according to any one of paragraphs.1-10, comprising mixing:
A) from 10 to 50 wt.% low molecular weight fraction homopolymer of ethylene or copolymer of ethylene and at least one of the co monomer C3-C10with mass-average molecular mass Mwless than 40 kg/mol;
B) from 18 to 60 wt.% high molecular weight fractions homopolymer of ethylene or copolymer of ethylene and at least one of the co monomer C3-C10with mass-average molecular mass Mwmore than 250 kg/mol and
C) from 10 to 70 wt.% fraction homopolymer of ethylene or copolymer of ethylene and at least one of the co monomer C3-C10having intermediate molecular mass, with the mass-average molecular mass Mwfrom 100 to 200 kg/mol, and the copolymer comprises repeating units derived from ethylene and at least one of the co monomer C3-C10with a mixture of polyethylenes having a single melting peak as determined by differential scanning calorimetry (DSC), with any fraction of copolymer contains from 1 to 15 wt.% the co monomer.

16. A mixture of polyethylenes, mainly consisting of three fractions (A), (b) and (C) Homo - or SOP is limera ethylene with different molecular weights, moreover, the copolymer comprises repeating units derived from ethylene and at least one of the co monomer C3-C10:
A) from 10 to 50 wt.% low molecular weight fraction homopolymer of ethylene or copolymer of ethylene and at least one of the co monomer C3-C10with mass-average molecular mass Mwless than 40 kg/mol;
B) from 18 to 60 wt.% high molecular weight fractions homopolymer of ethylene or copolymer of ethylene and at least one of the co monomer C3-C10having a melt flow index, determined according to ISO 1133 at 190°C and a load of 21.6 kg, PTR190/21less than 10 g/10 min, and
C) from 10 to 70 wt.% fraction homopolymer of ethylene or copolymer of ethylene and at least one of the co monomer C3-C10having an intermediate molecular weight, melt flow index, determined according to ISO 1133 at 190°C and a load of 21.6 kg, PTR190/21greater than fraction (B), and comprising from 5 to 50 g/10 min;
the mixture of polyethylenes has a single melting peak as determined by differential scanning calorimetry (DSC), with any fraction of copolymer contains from 1 to 15 wt.% the co monomer.



 

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18 cl, 5 tbl

FIELD: chemistry.

SUBSTANCE: invention relates to composition of polymodal polyethylene, which has improved resistance to cracking under impact of environment and higher rate of crystallisation. Composition contains ethylene homopolymer, two ethylene copolymers and nucleating agent in amount from 20 to 5000 ppm in terms of entire polyethylene composition. Second ethylene copolymer has higher molecular weight than first ethylene copolymer, and first ethylene copolymer has higher molecular weight than ethylene homopolymer.

EFFECT: obtained polyethylene composition possesses resistance to cracking under impact of environment (ASTM D1693, Conditions B, in 100% Igepal) more than or equal 40 days, and half time of crystallisation lower than or equal 70% of half time of crystallisation of polymodal polyethylene without nucleating agent.

12 cl, 1 tbl, 12 ex

FIELD: chemistry.

SUBSTANCE: invention relates to pipe, possessing increased resistance to growth of pipe cracks and manufactured from polyethylene composition, as well as to application of phenol type stabiliser (C) and phenol type stabiliser (D) to increase resistance of pipes to slow crack growth. Pipe consists of polyethylene composition, which includes basic resin and phenol type stabilisers (C) and (D), which are different. Stabiliser (C) contains, at least, one ester group, and stabiliser (D) does not contain any ester group. Basic resin of polyethylene composition contains first ethylene homo- or copolymer (A) and second ethylene copolymer (B), with comonomer(s) for copolymer (B) and, possibly, copolymer (A) representing C3-C20 alpha-olefins.

EFFECT: pipes in accordance with invention have stability in testing whole cut for creep (FNCT), measured in accordance with ISO 16770:2004, at least, 5000 h.

11 cl, 1 tbl, 3 ex

FIELD: chemistry.

SUBSTANCE: invention relates to method of obtaining cross-linked product. Method includes stage of polyethylene polymerisation, optionally, with one or more alpha-olefin comonomer(s) in presence of Ziegler-Natta catalyst, formation of product from said polymer and its further cross-linking. Ethylene polymer, obtained at the stage of polymerisation, contains double bonds carbon-carbon/1000 of carbon atoms in the range from more than 0.2 to fewer than 5.0 double bonds, is characterised by molecular-weight distribution (MWD) in the range from 3.3 to 15 and does not contain long-chain branches. Said polymer is selected from rubbers (POE), thermoplasts (POP) or very low density polyethylenes (ethylene copolymers) (VLDPE), which have range of density from 855 to 909 kg/m3, or linear low density polyethylenes (ethylene copolymers) (LLDPE) with density from 910 to 930 kg/m3, of middle density ethylene copolymers (MDRE) with density from 931 to 945 kg/m3.

EFFECT: obtained cross-linked products have good mechanical properties, meeting high requirements and strict norms.

9 cl, 4 tbl, 8 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a polyethylene moulding composition intended for making pipes, conduits and cables, and a method of producing said composition. The composition has a multimodal molecular-weight distribution, density in the range of 920 to 960 kg/m3, melt flow index MFI190/2 in the range of 0.05 to 10 g/10 min and Shore hardness D, measured according to ASTM D2240-05 (15 s), of at least 56.0. The composition contains at least three ethylene polymer fractions having different molecular weight. Each of the fractions A, B and C is an ethylene homopolymer or a copolymer of ethylene with at least one C3-C10 comonomer.In the composition, one of the fractions A, B and C is an ethylene homopolymer and at least one of the other fractions is an ethylene copolymer with content of said C3-C10 comonomer of 1-15 wt %. Fraction A has weight-average molecular weight Mw in the range of 15 to 40 kg/mol, fraction B - in the range of 70 to 200 kg/mol and fraction C - in the range of 220 to 400 kg/mol.

EFFECT: obtained polyethylene moulding composition has excellent mechanical properties, hardness and wear resistance, and also has high impact resistance and slow crack growth.

13 cl, 6 dwg, 6 tbl

FIELD: chemistry.

SUBSTANCE: at the first stage a polymer material to be recycled is loaded into a cutting-compacting device, equipped with a mixing or crushing device, after which the polymer particles are continuously moved and heated in the cutting-compacting device. In order to neutralise the formed products of destruction or decomposition into the softened but not yet melted polymer added is a solid, powder-like, preferably mineral, filling agent, usually used for dilution or as a diluting agent, for instance chalk, diatomaceous earth, zinc oxide, talc, activated coal and/or carbonate, in particular calcium carbonate, in an amount, at least, corresponding to the expected acidic or basic impact. The mixture is continuously mixed, moved, if necessary, crushed and supported in the form of separate pieces or freely flowing for a definite time.

EFFECT: method makes it possible to effectively neutralise acidic and basic compounds, which results in the reduction of corrosion and increase of the service term of machines.

30 cl, 2 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a bimodal polyethylene high-density composition for obtaining products by pressure moulding, in particular caps and plugging means. The composition includes bimodal high-density polyethylene, a composition of an inorganic alpha-nucleating agent, a composition of a friction-reducing agent, representing amide of primary fatty acid, and a composition with one or more additives, selected from antioxidants, acid acceptors, pigments and UV-stabilisers. The application of bimodal polyethylene in a combination with the inorganic alpha-nucleating agent, in particular, with talc and behenamide, as the friction-reducing agent, makes it possible to obtain the moulding composition with an unexpected and synergic impact on crystallisation temperature, and the composition friction coefficient.

EFFECT: composition by the invention demonstrates higher crystallisation temperature and lower friction coefficient.

14 cl, 5 tbl

FIELD: chemistry.

SUBSTANCE: claimed invention relates to a solvent-free polyethylene film, which can be applied, for instance, in membranes, packing, and ballistics. The polyethylene film has a ratio between the strength in the first direction in the film plane and the strength in the second direction in the film plane, perpendicular to the first direction, in the range of 0.1-10:1. The strength in, at least, one direction in the film plane constitutes not less than 0.2 GPa. The weight-average molecular weight of polyethylene constitutes not less than 500000 g/mol, and a value of ratio Mw/Mn does not exceed 6. The method of the said film manufacturing is performed by processing an initial polymer of polyethylene UHMWPE with the weight-average molecular weight of not less than 500000 g/mol by elastic shear modulus, determined immediately after melting at 160°C, not higher than 1.4 MPa, and a value of Mw/Mn ratio not higher than 6. Processing is carried out by pressing in the absence of a solvent. A stage of extraction is performed in such conditions that the temperature of the polymer film half-product does not exceed the temperature of the polymer melting at any time moment. During extraction the force is applied to the polymer film half-product in the first direction and in the second direction, which is perpendicular to the first direction.

EFFECT: film, possessing high strength more than in one direction in the film plane, is obtained.

15 cl, 2 tbl

FIELD: chemistry.

SUBSTANCE: invention relates to use of a stabilised composition based on an ethylene homo- or copolymer containing a combination of at least two sterically hindered amine compounds for making plastic articles for transportation and storage of esters of vegetable oil, preferably plastic fuel tanks for motor vehicles, including single-layer or multi-layer articles. At least one of the sterically hindered amine compounds is selected from compounds having the chemical formula:

and a chemical formula:

, where n is an integer ranging from 2 to 20. The invention also describes a plastic article and components for transportation and storage of liquid fuels, including biodiesel fuel.

EFFECT: high resistance to thermal oxidative decomposition caused by presence of liquid fuels, such as biodiesel fuel, including esters of vegetable oils, together with oxygen.

7 cl, 3 tbl, 7 ex

FIELD: chemistry.

SUBSTANCE: invention relates to heat sealable films, laminated materials, membranes or other polymer articles based on cross-linked polymers, having rubber-like heat resistance (heat deformation) and dimensional stability at temperature higher than the melting point of the polymer, while maintaining properties of the compound obtained by heat sealing (heat-adhesive compound). The heat sealable film contains at least one layer formed from a composition containing A) at least one polymer selected from a group comprising i) an ethylene-based polymer, ii) an ethylene/α-olefin/diene interpolymer and iii) a polymer based on a C4-C10 olefin, and B) at least one polymer selected from a group consisting of a propylene/ethylene interpolymer and a propylene/α-olefin interpolymer. Said film is cross-linked using radiation and/or chemical reagents.

EFFECT: polymer films and articles disclosed herein have improved mechanical properties and improved puncture resistance and can be used for high-temperature filling and processing in thermal or radiation sterilisation conditions, and as stretch films and shrink films.

13 cl, 9 dwg, 8 tbl

FIELD: chemistry.

SUBSTANCE: invention relates to method of obtaining cross-linked pipe and to cross-linked pipe, which contains cross-linked polymer composition, containing cross-linked ethylene polymer. method of manufacturing cross-linked pipe includes: (i) polymerisation of ethylene non-obligatorily with one or several comonomers (comonomer) in presence of Ziegler-Natta catalyst with obtaining ethylene polymer, which contains carbon-carbon double bonds; ethylene polymer has: (A) linkability, expressed through the level of gel content, equal, at least, 50 wt %, according to the measurement of disc-shaped sample of cross-linked ethylene polymer (ASTMD 2765-01, Method A, extraction in decalin); or/and (B) content of carbon-carbon double bonds in a number higher than 0.2 carbon-carbon double bond/1000 carbon atoms, according to the measurement by FTIR method; and (ii) obtaining polymer composition, including, at least, 50% wt % of ethylene polymer; (iii) formation of pipe from composition, obtained at stage (ii); (iv) cross-linking pipe, obtained at stage (iii). Ethylene polymer represents ethylene homopolymer or ethylene copolymer with one or several comonomers, and is selected from elastomers (POE), plastomers (OPO) or very low density ethylene copolymers of (VLDPE), which cover the density range from 855 to 909 kg/m3, linear low density ethylene copolymers (LLDPE), which have density in the range from 910 to 930 kg/m3 (ISO 1183), medium density ethylene copolymers (MDPE), which have density in the range from 931 to 945 kg/m3, or high density polyethylenes (HDPE), which are selected from homo- or copolymers of ethylene, and which have density higher than 946 kg/m3. Cross-linked pipe consists of cross-linked polymer composition. Polymer composition before cross-linking includes, at least, 50 wt % of ethylene polymer, where ethylene polymer is obtained by polymerisation of ethylene optionally together with one or several comonomers (comonomer) in presence of Ziegler-Natta catalyst, where ethylene polymer contains carbon-carbon double bonds in a number higher than 0.4 carbon-carbon double bond/1000 carbon atoms, according to the measurement by FTIR method, where ethylene polymer has linkability, expressed through the level of gel content, equal, at least, 50 wt %, according to the measurement for disc-shaped sample of cross-linked ethylene polymer (ASTMD 2765-01, Method A, extraction in decalin) and has MFR2 from 0.01 to 5.0 g/10 min, Mn/Mw from 0.1 to 20.0 g/10 min, and where ethylene polymer represents ethylene homopolymer or ethylene copolymer with one or several copolymers, and is selected from linear low density ethylene copolymers (LLDPE), which have density in the range from 910 to 930 kg/m3 (ISO 1183), medium density ethylene copolymers (MDPE), which have density in the range from 931 to 945 kg/m3, or high density polyethylenes (HDPE), which are selected from ethylene homo- or copolymers and which have density higher than 946 kg/m3.

EFFECT: improvement of material properties.

18 cl, 5 tbl

FIELD: chemistry.

SUBSTANCE: invention relates to crosslinkable compositions based on polyolefins and copolymers thereof and modifiers for producing silanol-crosslinkable polymer compositions which can be used to produce film coatings, insulation and sheaths for cables and conductors for different purposes. The silanol-crosslinkable composition contains polyolefin, vinyl alkoxysilane, organic peroxide and a sheet silicate which is modified with resorcinol resin with ratio of the resorcinol resin to the sheet silicate of 6:10 pts.wt.

EFFECT: improved operational characteristics, shorter crosslinking time and longer property retention time.

6 cl, 2 tbl

FIELD: process engineering.

SUBSTANCE: invention relates to production of sand blend or moulded article. Sand blend is composed on the mix of polyamide and master batch containing carbonic acid, particularly, with phenols or alcohols, and polyether amide. Polyamide has end groups, at least 50% of the latter are composed of end amine groups. Polyamide amount makes 10-99 wt %. Amount of polyether amide in master batch makes 1-90 wt %. Polyamide end groups, at least 50% thereof, are composed of end amine groups. This mix is stored and transported, if required. This mix is mixed in the melt at shear stress. Fused mix is unloaded and hardened to get sand batch of moulded article. Said moulded article represents a channel, plate or film.

EFFECT: produced article features higher content of end amino groups, higher resistance to hydrolysis.

9 cl

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