Polymer films

FIELD: chemistry.

SUBSTANCE: film is made by extrusion from an ethylene and alpha-olefin compolymer. Said ethylene and alpha-olefin copolymer is obtained during a gas-phase polymerisation process with formation of particles in the presence of a monocyclopentadienyl metallocene complex, a co-catalyst of general formula (L*-H)⁺ _d(A^d-), where L* is a neutral Lewis base, (L*-H)⁺ _d is a Brоnsted acid, A^d- is a non-coordinating associative anion, having a charge d^- and the anion includes an aryl-substituted borate, and d is an integer ranging from 1 to 3, of carrier material and alpha-olefin. Polymer film contains less than 300-600 gels/m² with size from 100 to 2000 mcm according to the invention of an optical inspection system.

EFFECT: reduced amounts of gels causing defects in transparency of films.

16 cl, 2 ex, 3 tbl

The present invention relates to polymeric films and polyethylene films containing a reduced number of gels. Films produced from polymers obtained by polymerization of olefins, particularly in the presence of supported catalysts for the polymerization with a single center of polymerization, specifically applied metallocene catalysts, which can provide advantages for carrying out gas-phase processes.

In recent years, many advances in the production of polyolefin homopolymers and copolymers achieved through the invention metallocene catalysts. Metallocene catalysts have the advantage of generally higher activity in comparison with conventional Ziegler catalysts, it is more commonly described as catalysts with a single center of polymerization.

There are several different families of metallocene complexes. In the first years of the developed catalysts based on bis(cyclopentadienyls) complexes of metals, examples of which can be found in EP 129368 or EP 206794. Not so long ago were developed complexes containing individual or mononitrobenzene ring. Such complexes are called complexes with complicated geometry, examples of such complexes can be found in EP 416815 or EP 420436. In both these complexes the metal atom, for example, zirconium, loc is in the highest degree of oxidation.

However, were developed and other complexes in which the metal atom may be in a lower oxidation state. Examples of such bis(cyclopentadienyls) and mono(cyclopentadienyls) complexes described in WO 96/04290 and WO 95/00526, respectively.

The above-described metallocene complexes used for polymerization in the presence of co-catalyst or activator. Usually activators are alumoxane specifically methylalumoxane, or compounds based on boron. Examples of the latter include borates, for example, trialkyl-substituted tetraphenyl or tetrafluoroborate or triarylmethane, for example, Tris(pentafluorophenyl)borane. The catalytic system containing borate activators described in EP 561479, EP 418044 and EP 551277.

The above-described metallocene complexes can be used for the polymerization of olefins in solution, suspension or gas phase. If they are used in suspension or gas-phase metallocene complex and/or activator is applied on suitable media. Typical carriers include inorganic oxides, such as aluminum oxide or, alternatively, you can apply polymeric carriers.

Examples of obtaining applied metallocene catalysts for polymerization of olefins can be found in WO 94/26793, WO 95/07939, WO 96/00245, WO 96/04318, WO 97/02297 and EP 642536.

Applied metallocene catalyst C which topics are particularly suitable for use in processes for the copolymerization of ethylene with one or more other alpha-olefins. Typically, the resulting copolymer may have a density in the range 0.900 for 0,940, they are called linear polyethylene of low density (LDL).

Typically, these copolymers can appropriately get in suspension or in the gas phase and turn it into a polymer film, for example, by extrusion blown.

Produced using metallocene catalysts film of linear low density polyethylene usually have better transparency and higher resistance than the films obtained from conventional linear low density polyethylene. Low levels of molecules with long chain branching in the films based on linear low density polyethylene also leads to improvement in their tensile strength.

The drawback of such films may be the presence of gels, which can lead to defects transparency. This disadvantage is particularly significant for films, which are used for packaging of food, for example, bags for bread and packaging for fresh produce, or when used in retail trade, where the transparency of the film is undoubtedly important.

The gels represent the vices of polyethylene films, which include, for example, fused dehomogenization material, and linear low density polyethylene (LDL) they can be formed by sections of polyeth the Lena high density. Gels can be formed under the action of catalyst, process conditions or under the influence of both reasons.

Unexpectedly, we found that the amount of gel present in the polymer films, can be reduced, if the copolymers produced by the process of polymerization in the gas phase with particle formation in the presence of catalytic systems with a single center of polymerization.

Thus, in accordance with the present invention, is provided a method of obtaining a film containing 300-600 gels/m²having a size in the range from 10 to 2000 μm, which is measured by the optical system control (ASC), described in the present description, with the specified film obtained from the copolymer of ethylene with alpha-olefin, characterized in that the copolymer produced by the process of polymerization with the formation of particles in the presence of a catalytic system with a single center of polymerization.

The expression "polymerization process with particle formation" means a process in which particles are formed of a polymer, for example, in the gas phase or in suspension.

Preferably, the film according to this invention contain 300-500 gels/m²having a size in the range from 10 to 2000 μm, which is measured by the optical system control (ASC).

Preferred films in accordance with the present invention is a film obtained by extrusion with uwom.

The copolymers, which are used to obtain new films of the present invention, the most appropriate way to prepare when using the applied catalytic systems with a single center of polymerization.

Suitable applied catalytic system with a single center polymerization include:

(a) the catalyst with a single center of polymerization;

(b) socialization and

(C) a material medium.

Preferred catalysts with a single center polymerization include metallocene complexes based on metals of groups IVA, for example, titanium, zirconium and hafnium.

Suitable metallocene complexes can be described with the General formula LxMQn, in which L represents cyclopentadienyls ligand, M represents a metal of group IVA, Q represents a leaving group, and x and n depend on the degree of oxidation of the metal.

Usually the metal of group IVA represents titanium, zirconium or hafnium, x is 1 or 2, and a typical leaving groups are halogen or hydrocarbonyl. Cyclopentadienyls ligands can be substituted, for example, alkyl or alkenylamine groups, or may include a condensed cyclic system, for example, indenyl or fluorenyl.

Examples of suitable metallocene complexes described in EP 129368 and EP 206794. Such complexes can be no bridge, e.g. the measures bis(cyclopentadienyl)zirconiated, bis(pentamethyl) cyclopentadienylcobalt, or can be bridged, for example, ethylenebis(indenyl)zirconiated or dimethylsilane (indenyl)zirconiated.

Other suitable bis(cyclopentadienyl) metallocene complexes are bis(cyclopentadienyl)diene complexes described in WO 96/04290. Examples of such complexes are bis(cyclopentadienyl)zirconium(2,3-dimethyl-1,3-butadiene) and ethylenebis(indenyl) zirconium 1,4-diphenylbutadiyne.

Preferred metallocene for use in the method according to the present invention are monosyllabically complexes.

Examples monosyllabically or substituted monosyllabically complexes suitable for use in the present invention, is described in EP 416815, EP 418044, EP 420436 and EP 551277. Suitable complexes can be described with the General formula CpMX_nwhere Cf is a separate cyclopentadienyls or substituted cyclopentadienyls group optionally covalently bound to M through a Deputy, M represents a metal of group IVA, associated communication η⁵with cyclopentadienyls or substituted cyclopentadienyls group X at each occurrence is a hydride or a group selected from the group comprising halogen, alkyl, aryl, Allok the sludge, alkoxyl, alkoxyalkyl, aminoacyl, siloxanes etc. containing up to 20 non-hydrogen atoms and neutral ligands based Lewis bases containing up to 20 non-hydrogen atoms, or optionally one X together with Wed forms metallocycle with M, n depends on the valency of the metal.

Especially preferred monosyllabically complexes have the formula:

in which R' each time independently selected from hydrogen, hydrocarbonyl, Silla, hermila, halogen, cyano group, and combinations thereof; specified R' contains up to 20 non-hydrogen atoms, and optionally two groups R' (where R' is hydrogen, halogen or cyano) together form a divalent derivative attached at adjacent positions to cyclopentadienyls ring with the formation of the condensed cyclic structures;

X is a hydride or a group selected from the group comprising halogen, alkyl, aryl, aryloxy, alkoxy, alkoxyalkyl, aminoalkyl, siloxanes etc. containing up to 20 non-hydrogen atoms and neutral ligands based Lewis bases containing up to 20 non-hydrogen atoms

Y represents-O-, -S-, -NR*-, -PR*-,

M represents hafnium, titanium or zirconium,

Z* is a SiR*₂CR*₂, SiR*₂SIR*₂CR*₂CR*₂, CR*=C*, CR*₂SIR*₂

or GeR*₂where R* at each occurrence independently represents hydrogen or a group selected from hydrocarbonyl, Silla, halogenated alkyl, halogenated aryl, and combinations thereof, and specified R* contains up to 10 non-hydrogen atoms, and optionally two groups R* Z* (where R* is not hydrogen), or an R* group from Z* and an R* group from Y form a cyclic system;

n is 1 or 2 depending on the valency M

Examples of suitable monosyllabically complexes are (tert-butylamide)dimethyl(tetramethyl-η⁵-cyclopentadienyl)sentimentalised and (2 methoxyphenylazo)dimethyl(tetramethyl-η⁵-cyclopentadienyl)sentimentalised.

Other suitable monosyllabically metallocene complexes include postinitialize ligands described in WO 99/40125, WO 00/05237, WO 00/05238 and WOOO/32653. A typical example of such a complex is cyclopentadienide[three(tert-butyl)phosphinic]dichloride.

Particularly preferred metallocene complexes for use in obtaining the supported catalysts of the present invention can be represented General formula

R' each time independently selected from hydrogen, hydrocarbonyl, Silla, hermila, halogen, cyano group, and combinations thereof; specified R' contains up to 20 N. the hydrogen atoms, and optional two groups R' (where R' is hydrogen, halogen or cyano) together form a divalent derivative attached at adjacent positions to cyclopentadienyls ring with the formation of the condensed cyclic structures;

X is a neutral η⁴group containing up to 30 non-hydrogen atoms, which forms a π-complex with M.

Y represents-O-, -S-, -NR*-, -PR*-,

M represents titanium or zirconium in the formal oxidation state of +2.

Z* is a SiR*₂CR*₂, SiR*₂SIR*₂CR*₂CR*₂, CR*=CR*, CR*₂SIR*₂

or GeR*₂where R* at each occurrence independently represents hydrogen or a group selected from hydrocarbonyl, Silla, halogenated alkyl, halogenated aryl, and combinations thereof, and specified R* contains up to 10 non-hydrogen atoms, and optionally two groups R* Z* (where R* is not hydrogen), or an R* group from Z* and an R* group from Y form a cyclic system.

Examples of suitable groups X are s-TRANS-η⁴-1,4-diphenyl-1,3-butadiene; s-TRANS-η⁴-3-methyl-1,3-pentadiene; s-TRANS-η⁴-2,4-hexadiene; s-TRANS-η⁴-1,3-pentadiene; s-TRANS-η⁴-1,4-ditolyl-1,3-butadiene; s-TRANS-η⁴-1,4-bis(trimethylsilyl)-1,3-butadiene; a-CIS-η⁴-3-methyl-1,3-pentadiene; s-CIS-η⁴-14-dibenzyl-1,3-butadiene; s-CIS-η⁴-1,3-pentadiene; s-CIS-η⁴-1,4-bis(trimethylsilyl)-1,3-butadiene, and the specified s-CIS diene group forming a π-complex with the metal, as defined in the present description.

The most preferred groups R' represent hydrogen, methyl, ethyl, propyl, butyl, pentyl, hexyl, benzyl or phenyl, or two R' groups (except hydrogen) are connected together, and in whole group C₅R'₄represents, for example, indenolol, tetrahydroindole, fluoroanilino, tetrahydrofuranyl or octahydrophenanthrene group.

Especially preferred groups Y are nitrogen - or phosphorus-containing groups containing group corresponding to the formula-N(R^//)- or-P(R^//)-, in which R^//represents a C_1-10hydrocarbonyl.

Most preferred complexes are aminosilane or aminoalkylsilane complexes.

Most preferred are complexes in which M represents titanium.

Specific complexes suitable for use in the preparation of supported catalysts of the present invention, is described in WO 95/00526 and incorporated into the present description by reference.

Particularly preferred complex for use in the preparation of supported catalysts of the present invention is (tert-is ethylamide) (tetramethyl-η ⁵-cyclopentadienyl) dimethylsilane-η⁴-1,3-pentadien.

Suitable socializaton for use in the catalytic systems according to the present invention is usually used in the above-mentioned catalysts with a single center of polymerization.

They include boron, for example, Tris(pentafluorophenyl)borane, and borates.

Suitable boron compounds include compounds trailmore. Especially preferred connection trailmore is Tris(pentafluorophenyl) borane.

Other compounds suitable for use as co-catalysts include the cation and anion. Cation is typically an acid Bronsted able to give a proton and the anion is usually a combined ncoordinates volume group capable of stabilizing cation.

Such co-catalysts can be represented by the formula:

(L*-H)⁺_d(A^d)

in which L* is a neutral Lewis base, (L*-H)⁺_drepresents the acid Branstad, A^drepresents gecoordineerde compatible anion having a charge of d^-, and d is an integer from 1 to 3.

The cation of the ionic compound can be selected from the group comprising acidic cations, carbonium cations, silyl cations, oxonium cations, ORGANOMETALLIC cations tatiania oxidants.

Suitable preferred cations include substituted trihydrochloride group cations of ammonium, for example, triethylamine, Tripropylamine, three(n-butyl)ammonium and the like. Also suitable for use cations are N,N-dialkylanilines, for example, N,N-dimethylaniline cations.

Preferred ionic compounds used as co-catalysts are those in which the cation includes substituted hydrocarbonyl group, ammonium salt and the anion comprises a substituted aryl group Borat.

Typical borates suitable for use as ionic compounds include: trimethylammoniumphenyl, triethylmethylammonium,dipropylenetriamine,three(n-butyl)ommunityserver, three (tert-butyl)ommunityserver, N,N-dimethylaminomethylene, N,N-diethylenetriaminepenta, trimethylaminobutyric(pentafluorophenyl)borate, triethylammonium(pentafluorophenyl)borate, tripropyleneglycol(pentafluorophenyl)borate, three (n-butyl) ammoniates(pentafluorophenyl)borate, N,N-dimethylanilines (pentafluorophenyl)borate, N,N-diethylaniline(pentafluorophenyl) borate.

The preferred co-catalyst suitable for use in conjunction with a catalyst with a single center of polymerization of the present invention, includes the nnye connection containing the cation and anion, and the anion has at least one Deputy, including a group containing an active hydrogen.

Suitable co-catalysts of this type are described in WO 98/27119, significant part of which is included in the present description by reference.

Examples of this type of anions include triphenyl(hydroxyphenyl)borate, three(para-tolyl)(hydroxyphenyl) borate, Tris(pentafluorophenyl)(hydroxyphenyl) borate, Tris(pentafluorophenyl)(4-hydroxyphenyl)borate.

Examples of suitable cations for this type of co-catalyst include triethylamine, triisopropanolamine, Diethylenetriamine, dibutylethanolamine and similar cations.

Particularly suitable cations containing longer alkyl chains, for example, vexillationes, dictatorially, detraditionalisation, bis(hydrogenated fatty alkyl)methylammonium and similar cations.

Particularly preferred co-catalysts of this type are Tris(pentafluorophenyl)-4-(hydroxyphenyl)borates of alkylamine. Particularly preferred co-catalyst is Tris(pentafluorophenyl)(4-hydroxyphenyl)borate, bis(hydrogenated fatty alkyl)methylamine.

In relation to this kind of co-catalyst is particularly preferred compound is the reaction product of Tris-(pentafluorophenyl)-4-(hydroxyphenyl)borate of alkylamine and metalloorganicheskoi connection for example, triethylamine.

Suitable materials for the carrier include inorganic metal oxides, alternatively you can apply polymeric carriers, e.g., polyethylene, polypropylene, clay, zeolites, etc.

Suitable inorganic metal oxides are SiO₂, Al₂O₃, MgO, ZrO₂, TiO₂B₂O₃, CaO, ZnO and mixtures thereof.

The most preferred material carrier for use with the applied catalysts in accordance with the method of the present invention is a silicon oxide. Suitable oxides include silicon Ineos ES70 and Grace Davison 948.

The material of the object can be heat treated and/or chemically treated to reduce the content of water or hydroxyl groups. Usually chemical dehydrating agents are reactive metal hydrides, alkyl derivatives of aluminum and its halides. Before applying the material of the carrier can be subjected to processing at a temperature of from 100 to 1000°C., preferably from 200 to 850°C in an inert atmosphere under reduced pressure.

Porous media are preferably pre-treated with the ORGANOMETALLIC compound, preferably alumoorganic connection, and most preferably the connection trialkylamine in dilute dissolve the barely.

Preferred compounds trialkylamine are triethylaluminium or triisobutylaluminum.

The material of the carrier pretreated ORGANOMETALLIC compound at a temperature of from -20 to 150°C, preferably from 20 to 100°C.

Other suitable carriers are described in our application GB 03/05207.

Applied catalysts with a single center of polymerization according to the present invention can be obtained by a method including:

(I) contacting in a suitable solvent

(a) catalyst with a single polymerization

(b) a co-catalyst that does not contain alumoxane, and

(b) a material medium,

(II) removing the solvent.

Suitable solvents for use in the preparation of supported catalysts of the present invention are aliphatic or aromatic hydrocarbons, such as pentane, isohexane, heptane, toluene or the like.

Obtaining the supported catalysts of the present invention is preferably carried out in a separate reactor.

The present invention is particularly suitable for use with metallocene complexes, which are processed capable of polymerization monomers. In our earlier application WO 04/020487 and WO 05/019275 described inflicted catalytic compositions which are capable of polymerization, the monomer is used when when the otoplenie catalyst.

Especially preferred catalytic system with a single center of polymerization for use in the method according to the present invention do not contain alumoxane as a co-catalyst.

Thus, in accordance with another aspect of the present invention provides a method of obtaining a marked catalytic system for polymerization, which includes:

(I) contacting in a suitable solvent

(a) a metallocene complex,

(b) not alumoxane co-catalyst

(C) porous media and

(d) capable of polymerization monomer,

(II) removing the solvent.

Capable of polymerization monomers suitable for use in this aspect of the present invention include ethylene, propylene, 1-butene, 1-hexene, 1-octene, 1-mission, styrene, butadiene, and polar monomers, for example, vipjatt, methyl methacrylate, etc. Preferred monomers contain from 2 to 10 carbon atoms and are specifically ethylene, propylene, 1-butene or 1-hexene.

Alternatively, you can apply a combination of one or more monomers, for example, ethylene and 1-hexene.

Preferred are capable of polymerization with the monomer for use in the present invention is 1-hexene.

Capable of polymerization, the monomer is suitably used in liquid form, or in cachedtablemodel, in the form of a solution in a suitable solvent. Suitable solvents include, for example, heptane.

Capable of polymerization, the monomer can be added to the co-catalyst prior to the addition of metallocene complex, or the complex can be pushed capable of polymerization with the monomer.

The method in accordance with a preferred aspect of the present invention includes the use of a catalytic system with a single center of polymerization, including mobiililaitteille metallocene complexes, and co-catalysts comprising ionic compound comprising a cation and anion, and the anion has at least one Deputy containing group which contains an active hydrogen.

The applied catalyst with a single center of polymerization according to the present invention may be suitable for carrying out copolymerization of olefin monomers selected from (a) ethylene or (b) of propylene with one or more alpha-olefins.

Applied catalytic system with a single center of polymerization according to the present invention is most suitable for use in the processes of polymerization in suspension or in the gas phase.

In suspension processes are generally used inert hydrocarbon diluent, and temperature range from about 0°C. to a temperature slightly below the temperature at to the Torah, the resulting polymer becomes practically soluble in the inert polymerization medium. Suitable diluents include toluene, or alkanes, e.g. hexane, propane or isobutane. The preferred temperature is from about 30 to about 200°C., but especially preferably from about 60 to 100°C. In the processes of polymerization in suspension widely used circulation reactors.

Gas-phase polymerization processes of olefins, specifically homopolymerization and copolymerization of ethylene and alpha-olefins, such as 1-butene, 1-hexene, 4-methyl-1-pentene, well known in this technical field.

Typical operating conditions for the gas phase include a temperature of from 20 to 100°C. and most preferably from 40 to 85°C, at a pressure of from subatmospheric to 100 bar.

Particularly preferred gas-phase processes carried out in the liquefied layer. Examples of such processes are described in EP 89691 and EP 699213, the latter is a particularly preferred process for use of supported catalysts of the present invention.

Preferred alpha-olefins are 1-butene, 1-hexene, 4-methyl-1-Penta and 1-octene.

The most preferred alpha-olefin is 1-hexene. Copolymers of ethylene with alpha-olefins of the present invention typically have a density component from to 0.900 to 0.930 g/cm³, preferably from 0.910 to 0,925 g/cm³.

Copolymers of ethylene with alpha-olefins present the mu invention typically have a molecular weight distribution, average of 3-5, preferably 3.5 to 4.5.

When using catalysts with a single center of polymerization according to the present invention can be obtained copolymer products which have a reduced content of the gels. Low content of gels obtained when using the catalyst according to the present invention, is especially significant when using the polymers in such demanding to the quality of the application as films obtained by extrusion blow.

The present invention will now be illustrated with reference to the attached examples.

Reduction

The tea: triethylamine.

The ionic compound A:[N(N)IU(C_18-22H_37-45)₂] [(C₆F₅)₃(p-C₆H₄)]

Complex A: (C₅Me₄SiMe₂N^tBu)Ti(η⁴-1,3-pentadien)

Example 1

The first component of the catalyst

To 337,0 kg of 10.72%macranthera ionic compounds And toluene was added within 15 minutes 27,4 kg 13,1%macranthera of tea in isohexane. The mixture was stirred for another 15 minutes to obtain a solution of the first component of the catalyst.

The mixture of metallocene complex and 1-hexene

To 109,3 kg 9,94% of the mass. the solution of the complex in heptane was added 83,0 kg of 1-hexene.

Processing of silicon oxide of tea

Under continuous stirring in the reactor is loaded and 1491 l isohexane and 397 kg of silicon oxide D948 (manufactured by W.R. Grace). The silica was pre-progulivali in nitrogen atmosphere, until the concentration of hydroxyl groups is not accounted for 1.53 mmol/g) was Added 19.3 kg of solution Octastat 2000 (manufactured by Innospec) in pentane (2 g/l) and the mixture was stirred for 15 minutes. Then slowly over 1 hour was added 571 kg of a 12%aqueous solution of triethylaluminum (tea) in isohexane, then the mixture was stirred for a further 1 hour at 30°C. the Suspension was filtered and thoroughly washed with isohexane, and then transferred into the dryer. Added 19 kg solution Octastat 2000 pentane (2 g/l) and the mixture was finally dried at 60°C under vacuum.

Received 248 kg of silicon oxide/tea. The content of aluminum in the solid, as it was found, was 1.3 mmol/g

Getting deposited catalyst

In a reactor were placed 499 kg of silicon oxide/tea containing Octastat 2000. Prepared as described above, the solution of the first component of the catalyst, applied to the reactor for 45 minutes and then the mixture was stirred for another 30 minutes.

Then the reactor was cooled to 14°C and for 30 minutes was added previously prepared as described above, the solution of the metallocene complex a and 1-hexene, and then the mixture was stirred for another 2.5 hours. During the addition the internal temperature is increased up to a maximum of 26°C.

Within 30 minutes was added 57.4 kg solution Octastat 2000 pentane (2 g/is), and the mixture was dried at 45°C for 24 hours under dynamic vacuum. During the drying air entry was reduced to a minimum and did not reverse the flow of nitrogen. Analysis of the resulting dry powder showed that the content of titanium is 46.1 mmol/g, the content of boron to 47.4 mmol/g, the aluminum content of 1.06 mmol/g and a content of residual solvent of 0.65% of the mass.

Example 2 polymerization

Deposited catalyst was tested in a gas-phase pilot plant fluidized bed in the continuous mode, the process conditions described in table 1. Maintained a continuous supply Octastat 2000 in relation to the feed rate of ethylene. In each case prepared linear copolymer of ethylene with 1-hexene low density.

Analysis of products

1. Granulation

Obtained in the reactor, the powder was mixed in a test production line extrusion twin-screw extruder Coperion ZSK 58) under the conditions shown below in table 2. In the additive consisted of 400 ppm million Irganox 1010 and 800 ppm million Irgafos 168.

Basic settings of the extruder is shown below in table 2.

The temperature of the melt at the entrance to the gear pump usually amounted to 245°C.

The specific energy is usually amounted to 0.17 kW/kg

These conditions are normal for extrusion, which are used in industry for similar resins.

2. The optical system control (ASC) for counting the number of gels

The content of the gels was measured using the optical system control device type IU-20/26 V2, including single extra is EP 20 mm thick, flat die plate, cooling rolls, the winding device and the optical detector. Used the following conditions:

- the speed of the screw 25.minutes

the temperature profile (supply of raw materials to the head) 190-200-205-210-215-220°C

- the temperature of the chill rolls: 75°C

the removal rate: 2.5 m/min

- tension when winding: 5%

- torque rollers: 5 Nm

Comparative product was tested before each new series of measurements by the method of the JUICE in the same conditions; this comparative product was a linear polyethylene of low density (LDL) 0,9 MI, which is used for the manufacture of films by extrusion blow (link XF660); static analysis of the control process carried out in order to confirm that it correctly applied the JUICE. For each tested product were conducted by two consecutive measurements, and if they fall into one interval, the result took the average. If they do not fall into one interval, conducted the third dimension.

Table 3 shows the content of the gel film obtained from the copolymer in accordance with the present invention. In example 1 described the film obtained from the copolymer produced in the above-described polymerization conditions at a partial pressure of pentane average of 1 bar, and in example 2 copolymer, the scientists at a partial pressure of pentane, average of 0.5 bar.

For comparison also described the film made from the sales of polymers.

LL0209AA is a copolymer of ethylene with butene firm Ineos Polyolefins obtained gas is aznoe polymerization in the presence of a catalyst of Ziegler-Natta.

The density was measured using column density measurements in accordance with method ISO 1872/1.

From table 3 we can see that the catalyst in accordance with the present invention enables to obtain polymeric products, the content of the gels in which low. Low content of gels in the polymers produced using the catalyst according to this invention, essentially in respect of the application of the polymer in the fabrication of films by extrusion blow, which impose very high requirements.

1. A method of obtaining a film for use in packaging food products containing 300-600 gels/m²ranging in size from 100 to 2000 μm, as measured by the optical system control (ASC), and which is produced by extrusion of a copolymer of ethylene with alpha-olefin, characterized in that the copolymer is produced in the process carried out in the gas phase with particle formation in the presence of a catalytic system with a single center of polymerization, including
(a) a metallocene complex, representing monosyllabically metallocene complex,
(b) socialization having the General formula
$${\left(L^{*}-H\right)}_d^{+}\left(A^{d-}\right)$$,
in which L* is a neutral Lewis base,
$${\left(L^{*}-H\right)}_d^{+}$$represents the acid Bronsted A^drepresents gecoordineerde compatible anion having a charge of d^-and the anion comprises a substituted aryl group borate; d is an integer from 1 to 3,
(C) the material of the carrier, and
(g) alpha-olefin.

2. The method according to claim 1, wherein the film contains 300-500 gels/m²ranging in size from 100 to 2000 microns.

3. The method according to claim 1, wherein the alpha-olefin selected from 1-butene, 1-hexene, 4-methyl-1-pentene and 1-octene.

4. The method according to claim 3, in which the alpha-olefin is a 1-hexene.

5. The method according to claim 1, wherein the copolymer of ethylene with alpha-olefin has a density of from to 0.900 to 0.930 g/cm³.

6. The method according to claim 5 in which the copolymer of ethylene with alpha-olefin has a density of from 0.910 to 0,925 g/cm³.

7. The method according to claim 1, in which metallocene has a General formula

in which R' each time independently selected from hydrogen, hydrocarbonyl, Silla, hermila, halogen, ceanography and their combinations; the specified R' contains up to 20 non-hydrogen atoms, and optionally two of the groups R' (where R' is not hydrogen, halogen or cyano) together form a divalent derivative attached at adjacent positions to cyclopentadienyls ring with the formation of the condensed cyclic structures;
X is a hydride or a group selected from the group comprising halogen, alkyl, aryl, aryloxy, alkoxy, alkoxyalkyl, aminoalkyl, siloxanes containing up to 20 non-hydrogen atoms and neutral ligands based Lewis bases containing up to 20 non-hydrogen atoms,
Y represents-O-, -S-, -NR*-, -PR*-,
M represents hafnium, titanium or zirconium,
Z* represents the$$Si{R}_2^{*}$$,$$C{R}_2^{*}$$,$$Si{R}_2^{*}Si{R}_2^{*}$$,$$C{R}_2^{*}C{R}_2^{*}$$, CR*=CR*,$$C{R}_2^{*}Si{R}_2^{*}$$
or$$GeR2*$$where R* at each occurrence independently represents hydrogen or a group selected from hydrocarbonyl, Silla, halogenated alkyl, halogenated aryl, and combinations thereof, and specified R* contains up to 10 non-hydrogen atoms, and optionally two groups R* Z* (where R* is not hydrogen), or an R* group from Z* and an R* group from Y form a cyclic system;
n is 1 or 2 depending on the valency M

8. The method according to claim 1, in which metallocene has a General formula

in which R' each time independently selected from hydrogen, hydrocarbonyl, Silla, hermila, halogen, ceanography and their combinations; the specified R' contains up to 20 non-hydrogen atoms, and optionally two groups R' (where R' is hydrogen, halogen or cyano) together form a divalent derivative attached at adjacent positions to cyclopentadienyls ring with the formation of the condensed cyclic structures;
X is a neutral η⁴related diene group containing up to 30 non-hydrogen atoms, which form a π-complex with M;
Y represents-O-, -S-, -NR*-, -PR*-,
M represents titanium or zirconium, with the formal oxidation state +2;
Z* represents the$Si{R}_2^{*}$,$$C{R}_2^{*}$$,$$Si{R}_2^{*}Si{R}_2^{*}$$,$$C{R}_2^{*}C{R}_2^{*}$$, CR*=CR*,$$C{R}_2^{*}Si{R}_2^{*}$$
or$$Ge{R}_2^{*}$$where R* at each occurrence independently represents hydrogen or a group selected from hydrocarbonyl, Silla, halogenated alkyl, halogenated aryl, and combinations thereof, and specified R* contains up to 10 non-hydrogen atoms, and optionally two groups R* Z* (where R* is not hydrogen), or an R* group from Z* and an R* group from Y form a cyclic system.

9. The method according to claim 8, in which M represents titanium.

10. The method according to claim 1, wherein the material of the carrier is silica.

11. The method according to claim 1, wherein the alpha-olefin is from the battle 1-hexene.

12. The method according to claim 1, in which the catalytic system with a single center of polymerization is prepared by contacting in a suitable solvent of the following substances:
(a) a metallocene complex,
(b) socialization;
(C) a porous carrier and
(g) alpha-olefin,
with the removal of solvent.

13. Film for use for food packaging, containing less than 300-600 gels/m²ranging in size from 100 to 2000 μm, as measured by the optical system control (ASC), and which is produced by extrusion of a copolymer of ethylene with alpha-olefin, characterized in that the copolymer is produced in the process carried out in the gas phase with particle formation in the presence of a catalytic system with a single center of polymerization, including
(a) a metallocene complex, representing monosyllabically metallocene complex,
(b) socialization having the General formula
$${\left(L^{*}-H\right)}_d^{+}\left(A^{d-}\right)$$,
in which L* is a neutral Lewis base;
$${\left(L^{*}-H\right)}_d^{}$$represents the acid Bronsted; A^drepresents gecoordineerde compatible anion having a charge of d^-and the anion comprises a substituted aryl group borate; d is an integer from 1 to 3,
(C) the material of the carrier, and
(g) alpha-olefin.

14. The film 13 containing 300-500 gels/m²ranging in size from 100 to 2000 microns.

15. The film according to item 13, which is obtained by extrusion-blow process.

16. The film according to item 13, in which the alpha-olefin is a 1-hexene.