RU2310665C1 - Ethylene polymerization and copolymerization catalyst, method of preparing solid catalyst component, and a method for production ultrahigh-molecular weight polyethylene - Google Patents

Abstract

FIELD: polymerization catalyst and polymer production.

SUBSTANCE: invention relates to preparation of high-activity catalyst deposited on solid support and designed for suspension polymerization of ethylene and copolymerization of ethylene with α-olefins, in particular, for production of ultrahigh-molecular weight polyethylene. Catalyst according to invention comprises organoaluminum compound (40-200 wt parts) and solid component (1 wt part) containing 12-15% catalytically active titanium compounds and 85-88% magnesium dichloride support prepared by interaction of magnesium metal, ethanol, aluminum, silicon, and titanium compounds, said solid component being represented by particles containing titanium, magnesium, chlorine, aluminum, and silicon at atomic ratio between 1.0:6:16:0.07:0,02 and 1:7:18:0.06:0.01, respectively. Described are also preparation of solid catalyst component, and (co)polymerization of ethylene at temperature between 0 and 100°C and pressure between 0.1 and 5.0 MPa. Catalyst according to invention allows obtaining polyethylene with elevated molecular weight under high polymer yield conditions, which minimizes time required for preparation of homogenous spinning solutions in the gel formation process and minimizes degree of degradation of dissolved polymer properties.

EFFECT: increased molecular weight and yield of polyethylene .

8 cl, 1 dwg, 3 tbl, 26 ex

Description

The present invention relates to the field of production of high molecular weight polyethylene, namely, to obtain a highly active catalyst based on titanium supported on a solid support and intended for suspension polymerization and copolymerization of ethylene with alpha-olefins, in particular for the production of ultrahigh molecular weight polyethylene.

One of the most important characteristics of high molecular weight polyethylene, which determines its operational properties in various fields of technology, is molecular weight. Polyethylene with a medium viscosity molecular weight M _η > 10 ^{6 is} conventionally called ultra-high molecular weight polyethylene (hereinafter referred to as UHMWPE). The value of M _η ≈ 10 ⁶ corresponds to the characteristic viscosity [η] ≈ 8. The quantitative relationship between M _η and [η] is determined by the expression: M _η = 5.37 · 10 ⁴ · [η] ^1.49 , proposed in [Berzen I ., Theyssen I., Oberhausen H. // Kunstoffe, 1978, Bd. 78, No. 1, S. 42 - 46].

With an increase in molecular weight, the strength and structural properties of a variety of UHMWPE products obtained by cold and hot pressing, orientation drawing, gel molding from solutions, extrusion, etc. are improved. The practical application of UHMWPE shows that polymers with a molecular weight are used in most applications M _η ≥ 3 · 10 ⁶ .

From the analysis of scientific and patent information, it follows that in the presence of supported catalysts titanmagnievyh under slurry polymerization conditions UHMWPE prepared with an intrinsic viscosity of from 9 to 25 dl / g at a temperature of 4070 ^C and an ethylene pressure of 0.1 MPa. It is also known that for a particular solid component of the catalyst, the molecular weight of UHMWPE can be controlled within certain limits by varying the chemical composition of the cocatalyst and the physical conditions of polymerization (temperature, pressure, concentration of reagents).

From the scientific literature for catalysts of various chemical composition it is known that when compounds having electron-donating properties (the so-called "external electron donors") and entering into reversible or irreversible reactions with catalyst components are added to the cocatalyst, the molecular weight distribution (MMP) of the resulting polyolefins and catalyst activity: [Effect of external and internal donors on the activity and stereospecificity of Ziegler-Natta catalysts. Soga K., Shiono T., Doi Y. // Makromolec. Chemistry. 1988. V. 7. P. 1531].

In particular, it is known that for a number of Ziegler catalysts, an increase in the mass fraction of chlorine in the composition of an organoaluminum compound leads to an increase in the average molecular weight of polyethylene and a decrease in catalytic activity [Keii T., Kinetics of Ziegler-Natta Polymerization, Kodansha, Tokyo, 1972; Keii T., in: Coordination Polymerization, Ed. by Chien J.C. W., Academic Press, New York, 1975, p. 263; Chirkov N.M., Matkovsky P.E., Dyachkovsky F.S., Polymerization on complex organometallic catalysts, Moscow, Khimiya publishing house, 1976].

Among the many and rapidly developing areas of practical use of new materials based on UHMWPE, one of the promising technologies is orientational drawing of UHMWPE with the production of appropriate fibers for the production of woven products (light armor protection of personnel and military equipment, especially strong slings, ropes, canvas, etc. .).

The main industrial technology for the production of high-modulus fibers from UHMWPE is gel molding from diluted spinning solutions in paraffin oil, followed by orientational drawing of the fibers. The manufacturability of this process and the quality of the resulting fibers depend on many factors, among which the molecular weight, dispersion and texture characteristics of the used UHMWPE powders seem relevant. For technologies for producing high-quality fibers, of practical interest are methods for producing UHMWPE, providing: a) high activity of the catalyst; b) the optimal dispersion and morphology of the obtained UHMWPE powders; c) a sufficiently high value of the average viscosity molecular weight; c) minimization of the presence of a low molecular weight fraction in the polymer.

A number of methods are known for producing UHMWPE, differing in type and properties of the used catalyst: chemical composition, morphology and particle size distribution of the particles of the solid component of the catalyst and the corresponding morphology and particle size distribution of the particles of the obtained polymer powder, the specific activity of the solid component and the molecular weight of UHMWPE.

Known catalysts and methods for producing UHMWPE with their use solve various problems associated mainly with technological parameters of the synthesis process of UHMWPE :

a) increased activity of catalytic systems;

b) an increase in the molecular weight of UHMWPE;

c) a change in the average size and particle size distribution of the particles of the solid catalyst component and, as a consequence, the particle size distribution and morphology of the particles of the obtained UHMWPE powders;

g) increasing the bulk density of the polymer powders by selecting special conditions for suspension polymerization, etc.

In the following known methods for the production of UHMWPE, Ziegler catalysts are used, including as a solid component of the catalyst the reaction products of various titanium compounds and magnesium-containing carriers or massive titanium trichloride, and organoaluminum solutions as a cocatalyst.

In the known method [according to RF patent No. 2064936, IPC C 08 F 110/02, 1993] ultrahigh-molecular weight polyethylene is obtained by suspension polymerization of ethylene at a pressure of 0.1 ÷ 5.0 MPa in the presence of a catalyst comprising titanium trichloride obtained by reduction of tetrachloride titanium with diethylaluminium chloride; and triethylaluminum. The method is characterized in that the catalyst system is pretreated with a higher alpha olefin or a mixture thereof from the group of 1-hexene, 1-octene and 1-decene. The method is intended to obtain highly dispersed UHMWPE powders with a low bulk density. A significant disadvantage of this method is the need to perform a special operation of alcohol decomposition and water washing of the obtained polymer from the catalyst residues due to the high content of active chlorine.

In a known manner [Pat. US No. 4962167, IPC C 08 F 4/654, 1990] to obtain UHMWPE, a supported catalyst is used, where the solid component of the catalyst is obtained by reacting magnesium dichloride with titanium tetraalkoxide, aluminum trichloride and an organosilicon compound. UHMWPE powder obtained by polymerizing ethylene at ⁷⁰ ° C has an intrinsic viscosity [η] = 16,6 dl / g. This method does not allow to obtain polymer powders with an average particle size of less than 250 microns and with a bulk density of less than 0.34 g / cm ³ .

A known method of producing UHMWPE and a method of preparing a solid component of a supported catalyst for the polymerization of ethylene by the interaction of titanium tetrachloride with a carrier resulting from the reaction of an organomagnesium compound with carbon tetrachloride [US Pat. RF №2064836, IPC B 01 J 31/38, 1996]. In Example 10 of this patent illustrates a slurry ethylene polymerization (cocatalyst - triisobutylaluminium) at ⁷⁰ ° C to obtain a UHMWPE having a molecular weight of 1.8 × 10 ^6. The advantage of the method is the ability to control the size of the catalyst particles at the stage of carrier synthesis. The disadvantage - the need to reduce the polymerization temperature below 50 ^{° C} for the synthesis of polymers having a molecular weight M _η ≥ 3 × 10 ^6.

The patent [RF No. 2176649, IPC C 08 F 10/02, 2000] describes a method for producing UHMWPE in the presence of a solid catalyst component obtained by applying titanium tetrachloride to highly dispersed magnesium chloride and activated by aluminum trialkyl compounds. The essence of this method is to increase the bulk density of UHMWPE powders obtained in the presence of supported catalysts with controlled particle size distribution as a result of suspension polymerization in two stages. The first stage (prepolymerization step) is carried out at an elevated temperature of 70 ÷ 80 ° ^C according to Example 6 in the presence of triisobutylaluminum (main polymerization temperature is ~ 60 ° ^C) molecular weight of UHMWPE is 3.7 × 10 ^6, and in the presence of triethylaluminum in Example 5 (main polymerization temperature is ~ 50 ° ^C) - 5.3 × 10 ^6.

The disadvantage of this method from the point of view of the requirements of gel molding technology is the increased bulk density that limits the swelling and dissolution of the polymer, as well as the presence in the composition of the obtained UHMWPE of a certain amount of a low molecular weight fraction of polyethylene, mainly formed in the first stage of polymerization and which only partially dissolves in the liquid phase reaction medium.

It should be emphasized that the problem of increasing the bulk density of polyolefin powders, which is important from the point of view of increasing the productivity of technological lines for their production (at the stages of separation and granulation of polymer powders), is not relevant from the point of view of optimal requirements for UHMWPE designed to obtain fibers using gel technology forming spinning solutions. At the same time, the molecular weight of polyethylene, as a rule, correlates with the multiplicity of stretching and tensile strength of the fibers obtained from UHMWPE.

In the application of Japan [60-158205 No. 59-12041 of 01.27.84, op. 08.19.85, IPC C 08 F 10/02] describes a catalyst, a method for producing a solid catalyst component and a method for producing ultra-high molecular weight powdery polyolefins, including UHMWPE. The solid component obtained by reacting (at a temperature of ≤ -20 ^о С) a solution of magnesium chloride in 2-ethylhexanol containing phthalic anhydride and titanium tetrachloride with the addition of phthalic acid esters, reprocessing the titanium tetrachloride solid product recovered at the first stage at 110 ^о С and containing up to 3.5 wt.% titanium, it exhibits a fairly high activity in the polymerization of virtually any alpha olefins and high stereospecificity in the polymerization of propylene and other methyl substituted alpha olefins. In particular, in the presence of a catalyst (slurry ethylene polymerization conditions: temperature 75 ^C, ethylene pressure of 0.8 MPa, a cocatalyst - with the addition of triethylaluminum as the electron donor compound trimethylmethoxysilane) powdered UHMWPE prepared with the following indicators: reduced catalyst activity - 2200 g _PE / (g _CAT · h · atm), average particle size ~ 300 ÷ 500 μm, bulk density up to 0.48 g / cm ³ , characteristic viscosity [η] = 24 dl / g. The advantages of this catalyst is a sufficiently high molecular weight of the obtained UHMWPE.

Significant disadvantages of the solid component of the catalyst include (from the point of view of the requirements of the technology for the preparation of spinning solutions) the large size and high density of polymer particles, which, as follows from experience, will significantly increase the preparation time of homogeneous spinning solutions and destabilize the processes of gel forming and orientation drawing in fiber production technology. In addition, this catalyst has a relatively low specific activity in suspension polymerisation of ethylene.

The known method [Pat. US No. 4972035, IPC C 08 F 2/14, 1990] for the preparation of highly dispersed UHMWPE powders in the presence of a catalyst obtained by the interaction of titanium tetrachloride and an alcohol solution of magnesium chloride with the addition of ethyl benzoate. A highly active solid component of catalyst of the present process are prepared by reacting titanium tetrachloride with a solution of magnesium chloride and benzoic acid ester of 2-ethylhexanol at a low temperature (≤ - ²⁰ ° C). The interaction with titanium tetrachloride is carried out in two stages: in the first stage with the addition of benzoic acid ester and separation of the solid product from the mother liquor, and in the second stage, the solid product is re-treated with titanium tetrachloride, the solid product is separated and washed with a hydrocarbon solvent. The resulting solid catalyst component, containing 3.5 wt.% Titanium, is modified by prepolymerization with hexene-1 in the presence of triethyl aluminum. The slurry polymerization conditions (temperature 60 ^C, ethylene pressure 0.3 MPa, polymerization duration 2 hours cocatalyst - triethylaluminum) observed highest average reduced catalyst activity ~ 3500 g _PE / (g _cat · hr · atm). In this method, UHMWPE powder with a bulk density of 0.15 ÷ 0.45 g / cm ³ and an intrinsic viscosity [η] = 14.3 dl / g, which corresponds to a molecular mass of M _η = 2.5 · 10 ^{6, is} obtained.

The disadvantage of this method of obtaining a solid component of the catalyst is the wide particle size distribution of UHMWPE powder : when 21500 g of _PE / g of _CAT and an average particle size of 60 ÷ 120 microns are obtained, the resulting polymer powder has a bulk density of 0.3 ÷ 0.4 g / cm ³ and includes 15 to 40 wt.% Particles with a size <60 microns, from 50 to 75 wt.% - with a size of 60 microns and up to 10 wt.% - with a size> 300 microns. The presence of relatively large (> 250 μm) and dense particles in the UHMWPE powder is a significant drawback, since it increases the time required for swelling and complete dissolution of the polymer in a continuous technological process for preparing homogeneous spinning solutions, and, as a result, entails a high degree of thermal degradation of the polymer and appropriate degree of degradation of its properties. In addition, this method is complicated by the need for prepolymerization treatment of the catalyst with hexene-1.

Among the known supported titanium-magnesium catalysts for suspension polymerization of ethylene to produce UHMWPE, the catalyst that is closest in technical essence and considered by us as a prototype to the present invention is a catalyst whose method for producing a solid component is described in RF patent No. 2243237, IPC C 08 F 4/16, 2004. This patent also claims a method for producing UHMWPE using a solid catalyst component. The solid component of the catalyst for the synthesis of UHMWPE is obtained by the following method, which includes four stages:

1) preparation in a hydrocarbon medium (decane) of an alcohol (in 2-ethyl-hexanol) solution of magnesium dichloride and aluminum trialkoxide or boron trialkoxide;

2) the interaction of the specified solution with a silicon compound containing alkoxy groups, and an ester comprising a hydroxy group;

3) the interaction of the obtained products with a mixture of titanium compounds (TiCl ₄ ) and silicon (SiCl ₄ ) to obtain a solid catalyst component in which the molar ratio of magnesium compound to aluminum compound and boron compound is ≥ 4;

4) additional processing of the solid component with titanium tetrachloride to obtain the final solid catalyst component.

According to the prototype method, UHMWPE is prepared by suspension polymerization of ethylene in the presence of the proposed catalyst, comprising the above solid component and an organoaluminum compound (triethylaluminium) at a concentration of the solid component of the catalyst (0.001.5) mmol / L (in terms of the titanium content in the catalyst) and the concentration of the organoaluminum compound ( triethylaluminum) defined by the ratio (5) mol / (mol of titanium). In addition, the method provides for preliminary polymerization in the presence of the proposed catalyst before its use, which complicates the method of producing UHMWPE. The proposed catalyst has a fairly high activity and provides UHMWPE powder with a characteristic viscosity of 19 dl / g, a narrow particle size distribution and a bulk density of 0.3.4 g / cm ³ , but from the point of view of a continuous gel-forming process at the preparation stage spinning solutions, the disadvantage of the prototype method is the increased density of polymer particles, limiting the processes of swelling and complete dissolution of the polymer before the stage of orientation drawing. In addition, this method does not allow to obtain UHMWPE with a characteristic viscosity of more than 24 dl / g.

The general disadvantage of the known methods, including the prototype, is the lack of information on the relationship between the chemical composition of the catalysts, the methods for their preparation and the methods for producing UHMWPE with the operational requirements of gel-forming technology and orientational drawing in the production of high-modulus fibers; therefore, a comparative analysis of the experimental data obtained is fundamental when reproducing the synthesis of UHMWPE according to known methods and for known catalysts.

The objectives of the invention.

1. The creation of a highly active solid component of the catalyst based on titanium chlorides, mounted on a magnesium-containing carrier, and intended for the synthesis of fiber-forming UHMWPE, providing manufacturability and stability of the processes of gel-forming and orientational drawing of fibers.

2. Obtaining a solid catalyst component, the particles of which are characterized by a sufficiently high dispersion and provide the formation of the corresponding UHMWPE powders with a reduced bulk density, capable of faster swelling and dissolution in paraffin oil.

3. Determination of the effective composition of the cocatalyst and solvent for regulating the molecular weight of UHMWPE and minimizing the proportion of low molecular weight component in UHMWPE.

Distinctive features of the method of producing UHMWPE of the present invention in relation to the prototype and analogues are:

a) increasing the activity of the catalyst and the intrinsic viscosity of the polymer;

b) the possibility of obtaining (due to the textural properties of the particles of the solid catalyst component) sufficiently finely dispersed and highly porous polymer particles, which increases the manufacturability of the gel-forming process to obtain highly modular fibers;

c) the use of effective electron-donating compounds in the cocatalyst, which allows, if necessary, to control the molecular weight and molecular weight distribution;

d) the use in suspension polymerisation of solvents containing aromatic and naphthenic hydrocarbons to minimize the low molecular weight fraction in the polymer;

d) the absence in the method of obtaining the stage of prepolymerization processing of the catalyst, which simplifies the technology for producing UHMWPE.

An essential distinguishing feature of the catalyst and the method for producing the solid catalyst component of the present invention with respect to the prototype [RF patent 2243237, IPC C 08 F 4/16, 2004] is a higher dispersion and lower particle density of polymer powders with the same yield achieved (g _PE / g _CAT ). An essential distinguishing feature of the method for producing UHMWPE according to the present invention with respect to the prototype is the use (as part of the cocatalyst) of effective electron-donating compounds and a solvent containing aromatic and naphthenic hydrocarbons.

The tasks are solved as follows.

The synthesis of the solid component of the catalyst is carried out in an inert gas atmosphere in four stages. In the first stage, a solution of triethylaluminum and methylcyclohexyl dimethoxysilane in heptane is metered into the reactor, which is loaded with ethanol, at a temperature of 10 ÷ 20 ^о С and continuous stirring for 1 ÷ 3 hours with the formation of a solution of aluminum triethoxide. In the second step was added to the reactor contents metallic magnesium, and then the temperature was raised to ⁷⁰ ° C and under continuous stirring allowed to react magnesium interaction and ethanol for 10 ÷ 20 hours to complete the chemical bonding of the metal and form a suspension of magnesium diethoxide. The resulting suspension is cooled to 10 ÷ 20 ° ^C. In the third step in an empty reactor is loaded with a homogeneous mixture of titanium tetrachloride and heptane and metered into the reactor at a temperature of 0 ÷ 20 ^{° C} the above-prepared suspension of magnesium alkoxide. After addition, the reactor contents were heated ^to 100 ° C and kept under stirring for two hours, the solid product was separated from the liquid phase. In the fourth stage, a mixture of titanium tetrachloride and heptane is added to the solid product and the solid is re-treated under conditions similar to the third stage. After isolation of the solid product and washing with an inert solvent from the by-products, a solid catalyst component is obtained.

Suspension polymerization of ethylene with the formation of fiber-forming UHMWPE or copolymerization of ethylene with an alpha-olefin is carried out in the presence of a catalyst containing the above-obtained solid component and cocatalyst, which is a mixture of organoaluminum and electron-donating compounds in an aliphatic or mixed solvent containing aromatic and (or) naphthenic hydrocarbons.

The obtained catalyst according to this invention has an optimal particle size of from 0.5 to 4 μm, under the conditions of the method for producing UHMWPE or copolymerization of ethylene with alpha-olefins according to this invention shows high activity (up to 4000 g _PE / (g _KAT · h · ATM) when 50 ^about C) and allows you to get powders of UHMWPE or copolymers with a bulk density of 0.15 ÷ 0.2 g / cm ³ with a fairly "loose" particle texture. A sufficiently high dispersion and high porosity of the polymer particles minimize the time required for the preparation of homogeneous spinning solutions in the gel-forming process. In addition, this catalyst, by adjusting the compositions of the cocatalyst and solvent, as well as the physical conditions of suspension polymerization, allows, within certain limits, the molecular weight distribution and the average molecular weight characterized by [η] and the mass fraction of the low molecular weight fraction in UHMWPE to be minimized. Suspension polymerization of ethylene is carried out at concentrations of the solid component (in terms of mol of titanium) in the range of (1500) · 10 ^-6 mol / l, preferably (3 ÷ 100) · 10 ^-6 , and the concentration of organoaluminum compound is 20 mol / (mol of titanium) , preferably 50 ÷ 700 mol / (moles of titanium), at 0 ° ÷ 200 ^{° C,} preferably at 40 ÷ 90 ^{° C,} and pressure (0,1 ÷ 1,2) MPa, preferably (0.2 ÷ 1.0 ) MPa.

The following examples illustrate the invention. Wherein:

a) examples 1 illustrate the solid component of the catalyst and the method for its preparation (table 1);

b) examples 11–23 illustrate a method for producing UHMWPE, including example 12 (p) illustrates a method for producing UHMWPE in a pilot installation (table 2);

c) table 3 illustrates the test results of the properties of UHMWPE samples under the conditions of gel-forming technology and orientational drawing of fibers, including:

- UHMWPE samples obtained in the presence of various variants of the solid component of the catalyst and triethylaluminium (examples 1, 4 ÷ 6, 8 ÷ 10; table 1);

- samples obtained in the presence of a solid component according to example 1, but with varying the composition of the cocatalyst, solvent and polymerization conditions of ethylene (examples 11, 12 (p), 14, 18, 20, 23; table 2).

Example 1. All operations are performed in an atmosphere of chemically inert gas (nitrogen, argon, etc.) under conditions of continuous mixing of the reaction media. In a dry glass reactor equipped with a dropping funnel, stirring and thermostating devices, 149.5 g (3.25 mol) of dehydrated ethanol are charged at room temperature in a nitrogen atmosphere. A solution containing 5.7 g (0.05 mol) of triethyl aluminum and 9.9 ml (0.05 mol) of methylcyclohexyl dimethoxysilane in 50 ml (0.35 mol) of heptane is loaded into the funnel. In the first stage of the synthesis, the contents of the funnel are uniformly dosed into the reactor. The molar ratios of the reactants upon receipt of the solution (ethanol): (triethylaluminum): (silicon compound): (heptane) correspond to 6.5: 0.1: 0.1: 0.7. The reaction is carried out at a temperature of from 0 ^to 20 ° C for two hours. After addition, the reaction mixture was kept under stirring for 1 hour at 20 ^o C. The second step in the same reactor, to the resulting solution of the reaction products of magnesium metal are added in an amount of 12.15 g (0.5 mol), which corresponds to a molar ratio of C ₂ H ₅ OH / Mg = 6,5, the temperature was raised to ⁷⁰ ° C and is conducted isothermally for 12 hours the reaction of metallic magnesium interaction with components of the solution to form a suspension of magnesium alkoxide and aluminum in the liquid phase comprising ethanol and heptane. The reactor contents were cooled to 0 ° ^C. In the third step in an empty reactor is charged with titanium tetrachloride in an amount of 555 ml (5 mol), which corresponds to an atomic ratio Ti / Mg = 10, and heptane in an amount of 330 ml (2.25 mol) was dissolved the reactor was cooled ^to 0 ° C and this solution is metered cooled suspension of magnesium ethoxide and aluminum from the previous reactor. Dosage of the suspension is carried out discretely in the same portions of 15 ÷ 25 ml for two hours, the evolving hydrogen chloride is continuously removed from the reactor through a sequentially located shutter with mineral oil and a water-alkaline trap. During the dosage of the suspension in the reactor maintain the temperature in the range 0 ÷ 10 ^about C.

After closure dosage raise reactor temperature ^to 100 ° C isothermally and the mixture is kept for two hours.

Upon completion of exposure, the reaction mixture is left to stand until the solid phase precipitates completely, and the liquid phase is removed using a siphon. In the fourth stage, titanium tetrachloride in the amount of 460 ml (3.5 mol), which corresponds to the atomic ratio Ti / Mg = 8, and heptane in the amount of 250 ml (1.75 mol) are re-charged into the reactor, the reactor is heated to a temperature of 100 ^о С and isothermally incubated for two hours, followed by successive execution of the sedimentation of the solid phase and siphoning of the liquid phase. The isolated solid was washed with heptane three times with portions of 500 ml at ⁹⁰ ° C for 30 min for each wash, and isolated a solid catalyst component in an amount of 42 g.

According to elemental analysis, the obtained solid catalyst component, having particles with a size of 0.5 to 3 μm, contains titanium, magnesium, chlorine, aluminum and silicon in an atomic ratio of 1.0: 6.4: 16.8: 0.064: 0.014, respectively . The titanium content in the solid component is 3.2 wt.%, Which corresponds to 12.7 wt.% Of the catalytically active titanium compound (in terms of titanium tetrachloride) and 87.3 wt.% Of the carrier (in terms of magnesium dichloride).

Testing of the catalyst, including the obtained solid component and triethylaluminum, under conditions of periodic suspension polymerization of ethylene is performed as follows. In a 2.5 L autoclave in a countercurrent flow of ethylene, 1 L of a solution of triethylaluminum in heptane containing 0.6 g of triethylaluminum and 0.007 g of a solid catalyst component was successively charged at room temperature. The temperature was raised and the ethylene pressure in the reactor ^to 50 ° C and 0.3 MPa, respectively, and the polymerization are in the stationary conditions with vigorous stirring over three hours. Obtained 255 g of UHMWPE having an intrinsic viscosity [η] = 24,1 dl / g (measured in decalin at ¹³⁵ ° C). During the polymerization, the activity of the catalyst is stationary and amounts to 4050 g _PE / (g _CAT · h · atm). With the achieved yield of 36450 g _PE / g _CAT , UHMWPE powder with a particle size of 15 to 70 μm and a bulk density of 0.14 g / cm ^{3 is} obtained. After the polymer suspension is unloaded from the reactor, the solvent is separated from the polymer and its aliquot (200 ml) is completely evaporated, the weight of the dry residue (polyethylene wax) is determined, calculated on the total solvent volume (1 l) and expressed in wt.% Of the total powder weight. As a result, the yield of the low molecular weight fraction of polyethylene in this example was 0.04 wt.%.

Example 2. The solid component of the catalyst is obtained analogously to example 1, with the difference that in the first stage, when obtaining a solution of aluminum triethoxide, the molar ratios (ethanol) : (triethylaluminum): (silicon compound): (heptane) correspond to 7.5: 0.15 : 0.15: 1.5, and the atomic ratio Ti / Mg in the third and fourth stages is 8 and 6, respectively. The solid catalyst component is isolated in an amount of 41.5 g.

According to elemental analysis, the resulting solid catalyst component, having particles with a size of 0.5 to 3 μm, contains titanium, magnesium, chlorine, aluminum and silicon in an atomic ratio of 1.0: 6.5: 16.3: 0.067: 0.016, respectively . The titanium content in the solid component is 3.3 wt.%, Which corresponds to 13.1 wt.% Of the catalytically active titanium compound (in terms of TiCl ₄ ) and 86.9 wt.% Of the carrier (in terms of MgCl ₂ ).

The test of the catalyst is carried out under conditions similar to example 1. Get 243 g UHMWPE having an intrinsic viscosity of 21.5 dl / g During the polymerization, the activity of the catalyst is stationary and amounts to 3850 g _PE / (g _CAT · h · atm). With the achieved yield of 34650 g _PE / g _CAT , UHMWPE powder with a particle size of 20 to 80 μm and a bulk density of 0.16 g / cm ^{3 is} obtained. The yield of the low molecular weight fraction of polyethylene was 0.045 wt.%.

Example 3. The solid component of the catalyst is obtained analogously to example 1, with the difference that the atomic ratio Ti / Mg in the third and fourth stages (when treated with titanium tetrachloride) is 9 and 5, respectively. The solid catalyst component is isolated in an amount of 41.3 g. According to elemental analysis, the obtained solid catalyst component having particles with a size of from 0.5 to 9 μm contains titanium, magnesium, chlorine, aluminum and silicon in an atomic ratio of 1.0: 6, 3: 17.2: 0.066: 0.015, respectively. The titanium content in the solid component is 3.3 wt.%, Which corresponds to 13.1 wt.% Of the catalytically active titanium compound (in terms of TiCl ₄ ) and 86.9 wt.% Of the carrier (in terms of MgCl ₂ ). The test of the catalyst is carried out under conditions similar to example 1. Get 190 g of UHMWPE having an intrinsic viscosity of 19.2 dl / g During the polymerization, the activity of the catalyst is stationary and amounts to 3100 g _PE / (g _CAT · h · atm). With the achieved yield of 27900 g _PE / g _CAT , UHMWPE powder with a particle size of 10 to 150 μm and a bulk density of 0.25 g / cm ^{3 is} obtained. The output of the low molecular weight fraction of polyethylene was 0.05 wt.%.

Example 4. The solid component of the catalyst is obtained analogously to example 1, with the difference that in the first stage of the synthesis, the molar ratios of the reactants (ethanol): (triethylaluminum): (silicon compound): (heptane) correspond to 7.5: 0.15: 0, 15: 1.5, and in a third step synthesis Ti / Mg = 7. atomic ratio Isolate the solid catalyst component in an amount of 40.9 g According to elemental analysis of the resulting solid catalyst component having a particle size of from 0.6 to 4 .mu.m , contains titanium, magnesium, chlorine, aluminum and silicon in an atomic ratio of 1.0: 6.35: 17.0: 0.065: 0 , 014, respectively. The titanium content in the solid component is 3.45 wt.%, Which corresponds to 13.7 wt.% Of the catalytically active titanium compound (in terms of TiCl ₄ ) and 86.3 wt.% Of the carrier (in terms of MgCl ₂ ). The test of the catalyst is carried out under conditions similar to example 1. Obtain 176 g of UHMWPE having an intrinsic viscosity of 18.5 dl / g. During the polymerization, the activity of the catalyst is stationary and amounts to 2800

g _PE / (g _CAT · h · atm). With the achieved yield of 25200 g _PE / g _CAT , UHMWPE powder with a particle size of 5 to 180 μm and a bulk density of 0.32 g / cm ^{3 is} obtained. The output of the low molecular weight fraction of polyethylene was 0.06 wt.%.

Example 5. The solid component of the catalyst is obtained analogously to example 1 with the difference that in the first stage of the synthesis, the molar ratios of the reactants (ethanol): (triethylaluminum): (silicon compound): (heptane) correspond to 7.5: 0.15: 0.15 : 1.5, and in the second stage, the molar ratio C ₂ H ₅ OH / Mg = 7.5. The solid component of the catalyst is isolated in an amount of 40.1 g. According to elemental analysis, the resulting solid catalyst component, having particles with a size of 0.5 to 3 μm, contains titanium, magnesium, chlorine, aluminum and silicon in an atomic ratio of 1.0: 6 35: 17.0: 0.065: 0.014, respectively. The titanium content in the solid component is 3.25 wt.%, Which corresponds to 12.9 wt.% Of the catalytically active titanium compound (in terms of TiCl ₄ ) and 87.1 wt.% Of the carrier (in terms of MgCl ₂ ). The test of the catalyst is carried out under conditions similar to example 1. Get 251 g UHMWPE having an intrinsic viscosity of 24.0 dl / g During the polymerization, the activity of the catalyst is stationary and amounts to 3980 g _PE / (g _CAT · h · atm). With a yield of 35820 g _PE / g _KAT , UHMWPE powder with a particle size of 10 to 60 μm and a bulk density of 0.15 g / cm ^{3 is} obtained. The output of the low molecular weight fraction of polyethylene was 0.04 wt.%.

EXAMPLE 6 The solid catalyst component prepared as in Example 2, with the difference that in the first stage the molar ratio of C ₂ H ₅ OH / Mg = 7,5. The solid catalyst component is isolated in an amount of 41.7 g. According to elemental analysis, the obtained solid catalyst component, having particles with a size of from 0.6 to 4.5 μm, contains titanium, magnesium, chlorine, aluminum and silicon in an atomic ratio of 1.0 : 6.45: 16.9: 0.066: 0.015, respectively. The titanium content in the solid component is 3.28 wt.%, Which corresponds to 13 wt.% Of the catalytically active titanium compound (in terms of TiCl ₄ ) and 87 wt.% Of the carrier (in terms of MgCl ₂ ). The test of the catalyst is carried out under conditions similar to example 1. Receive 236 g UHMWPE having an intrinsic viscosity of 20.5 dl / g During the polymerization, the activity of the catalyst is stationary and amounts to 3750 g _PE / (g _CAT · h · atm). With the achieved yield of 33750 g _PE / g _CAT , UHMWPE powder with a particle size of 15 to 90 μm and a bulk density of 0.17 g / cm ^{3 is} obtained. The output of the low molecular weight fraction of polyethylene was 0.04 wt.%.

Example 7. The solid component of the catalyst is obtained analogously to example 3, with the difference that in the first stage, the molar ratio C ₂ H ₅ OH / Mg = 7.5. The solid component of the catalyst is isolated in an amount of 41.5 g. According to elemental analysis, the solid component of the catalyst, having particles with a size of from 0.6 to 7 μm, contains titanium, magnesium, chlorine, aluminum and silicon in an atomic ratio of 1.0: 6, 6: 17.3: 0.067: 0.016, respectively. The titanium content in the solid component is 3.28 wt.%, Which corresponds to 13.1 wt.% Of the catalytically active titanium compound (in terms of TiCl ₄ ) and 86.9 wt.% Of the carrier (in terms of MgCl ₂ ). The test of the catalyst is carried out under conditions similar to example 1. Obtain 170 g of UHMWPE having an intrinsic viscosity of 18.2 dl / g. During the polymerization, the activity of the catalyst is stationary and amounts to 2700 g _PE / (g _CAT · h · atm). With the achieved yield of 24300 g _PE / g _CAT , UHMWPE powder with a particle size of 5 to 220 μm and a bulk density of 0.31 g / cm ^{3 is} obtained. The output of the low molecular weight fraction of polyethylene was 0.07 wt.%.

Example 8. The solid component of the catalyst is obtained analogously to example 4, with the difference that in the first stage, the molar ratio C ₂ H ₅ OH / Mg = 7.5. The solid component of the catalyst is isolated in an amount of 41.5 g. According to elemental analysis, the solid component of the catalyst, having particles with a size of from 0.5 to 10 μm, contains titanium, magnesium, chlorine, aluminum and silicon in an atomic ratio of 1.0: 6, 1: 16.3: 0.069: 0.018, respectively. The titanium content in the solid component is 3.65 wt.%, Which corresponds to 14.5 wt.% Of the catalytically active titanium compound (in terms of TiCl ₄ ) 85.5 wt.% Of the carrier (in terms of MgCl ₂ ). The test of the catalyst is carried out under conditions similar to example 1. Receive 167 g of UHMWPE having an intrinsic viscosity of 17.8 dl / g During the polymerization, the activity of the catalyst is stationary and amounts to 2650 g _PE / (g _CAT · h · atm). With a yield of 23850 g _PE / g _KAT , UHMWPE powder with a particle size of 10 to 300 μm and a bulk density of 0.35 g / cm ^{3 is} obtained. The output of the low molecular weight fraction of polyethylene was 0.08 wt.%.

Examples 9 and 10 are comparative and illustrate the effect of the presence of aluminum triethoxide and methylcyclohexyl dimethoxysilane on the characteristics of the solid catalyst component.

Example 9. The solid component of the catalyst is obtained analogously to example 2, with the difference that in the first stage there is no triethylaluminium. The solid catalyst component is isolated in an amount of 41.8 g. According to elemental analysis, the solid catalyst component having particles with a size of 0.5 to 8 μm contains titanium, magnesium, chlorine and silicon in an atomic ratio of 1.0: 6.5: 16.3: 0.015, respectively. The titanium content in the solid component is 3.25 wt.%, Which corresponds to 12.9 wt.% Of the catalytically active titanium compound (in terms of TiCl ₄ ) and 87.1 wt.% Of the carrier (in terms of MgCl ₂ ). The test of the catalyst is carried out under conditions similar to example 1. Receive 240 g of UHMWPE having an intrinsic viscosity of 22.9 dl / g. During the polymerization, the activity of the catalyst is stationary and amounts to 3850 g _PE / (g _CAT · h · atm). With the achieved yield of 34,650 g _PE / g _CAT , UHMWPE powder with a particle size of 5 to 250 μm and a bulk density of 0.26 g / cm ^{3 is} obtained. The output of the low molecular weight fraction of polyethylene was 0.04 wt.%.

Example 10. The solid component of the catalyst is obtained analogously to example 6, with the difference that in the first stage there is no methylcyclohexyl dimethoxysilane. The solid component of the catalyst is isolated in an amount of 41.6 g. According to elemental analysis, the solid component of the catalyst, having particles with a size of from 0.6 to 6.5 microns, contains titanium, magnesium, chlorine and aluminum in an atomic ratio of 1.0: 6, 49: 17.6: 0.066, respectively. The titanium content in the solid component is 3.22 wt.%, Which corresponds to 12.8 wt.% Of the catalytically active titanium compound (in terms of TiCl ₄ ) and 87.2 wt.% Of the carrier (in terms of MgCl ₂ ). The test of the catalyst is carried out under conditions similar to example 1. Receive 236 g UHMWPE having an intrinsic viscosity of 22.4 dl / g During the polymerization, the activity of the catalyst is stationary and amounts to 3770 g _PE / (g _CAT · h · atm). With a yield of 33930 g _PE / g _KAT , UHMWPE powder with a particle size of 10 to 270 μm and a bulk density of 0.25 g / cm ^{3 is} obtained. The output of the low molecular weight fraction of polyethylene was 0.03 wt.%.

Table 1 contains the main indicators for examples 1 ÷ 10.

Examples 11–23 illustrate the hallmarks of the method for producing UHMWPE according to this invention, including the composition of the cocatalyst, the composition of the solvent (i.e., the presence of aromatic (toluene) and naphthenic (methylcyclohexane) hydrocarbons in the aliphatic C ₇ fraction) and the polymerization temperature. In all examples 11–23, the solid catalyst component obtained under the conditions of Example 1 is used. In this case, the observed bulk density and particle sizes of the polymers are close to the results of Example 1. Example 12 (p) refers to the continuous synthesis of UHMWPE under the conditions of a pilot installation and is analogue of example 12, performed in laboratory conditions. Table 2 is compiled according to examples 11 ÷ 23.

Example 11. Suspension polymerization of ethylene is carried out under conditions similar to example 1, with the difference that a solvent containing 10 wt.% Toluene and 40 wt.% Naphthenic hydrocarbon (methylcyclohexane) is used, the rest up to 100% - aliphatic C ₇ fraction. 253 g of UHMWPE are obtained having [η] = 24.4 dl / g. During the polymerization, the activity of the catalyst is stationary and is 4020 g _PE / (g _CAT · h · atm). The output of the low molecular weight fraction of polyethylene was 0.13 wt.%.

Example 12. Suspension polymerization of ethylene is carried out under conditions analogous to example 1, with the difference that methylcyclohexyl dimethoxysilane in atomic ratio Al / Si = 20 is added to the cocatalyst (triethylaluminium) and a solvent containing 6 wt.% Toluene and 35 wt.% Naphthenic is used hydrocarbon (methylcyclohexane). 250 g of UHMWPE are obtained having [η] = 27.2 dl / g. During the polymerization, the activity of the catalyst is stationary and amounts to 4000 g _PE / (g _CAT · h · atm). The output of the low molecular weight fraction of polyethylene was 0.043 wt.%.

Example 12 (pilot). The continuous suspension process of ethylene polymerization is carried out in a hydrocarbon solvent medium containing 6 wt.% Toluene and 35 wt.% Methylcyclohexane.

Schematic diagram of the pilot plant for the synthesis of UHMWPE is shown in the drawing. In the main polymerization reactor 1, equipped with a mixing device, automatic control systems for temperature, pressure and heat removal, all components of the reaction medium are continuously fed in a predetermined ratio : a heptane suspension of a solid catalyst component with a concentration of 0.3 g / l by a metering pump 2 is uniformly supplied from the apparatus 3 to the reactor 1 with a flow rate of 3.5 kg / h; a solution of triethylaluminum with a concentration of 5 g / l dosing pump 4 is uniformly fed from the apparatus 5 into the reactor 1 with a flow rate of 22 kg / h; a solution of methylcyclohexyl dimethoxysilane with a concentration of 0.4 g / l by the metering pump 6 is uniformly supplied from the apparatus 7 to the reactor 1 with a flow rate of 22 kg / h; the solvent of the above composition by pump 8 is fed from the apparatus 9 into the reactor with a flow rate of 100 kg / h; ethylene through the flow meter 10 continuously enters the reactor with a flow rate of 52 kg / h

Thus, continuous suspension polymerization of ethylene in a pilot plant is carried out in the following ratio of catalyst components, wt. parts : organoaluminum compound 100, solid component 1.

The technological scheme of the continuous process allows you to adjust the ratio of the costs of these components of the reaction medium and the composition of the used solvent.

Under the conditions of this example, the polymerization reaction is carried out at ⁵⁰ ° C, a pressure of 0.3 MPa and an average residence time of the catalyst (the contact time) for 3 hours. A UHMWPE powder suspension stream is continuously withdrawn from the reactor, the flow rate of which is equal to the sum of the costs of its constituent components. The UHMWPE slurry stream from the reactor 1 continuously enters the monomer 11 degassing apparatus, the ethylene released after cooling in the heat exchanger 12 and compression by the compressor 13 is recycled. Then, the polymer suspension stream is pumped continuously by the pump 14 to the following stages: the stage of centrifuging the suspension into the apparatus 15 and discharging the “wet” powder into the hopper 16, the stage of drying into the apparatus 17 and the packing of UHMWPE commercial powder (into the hopper 18). After the fugging, the solvent enters the collector 19 and then is pumped to the distillation unit 20 with a pump 22, from where it is recycled through the heat exchanger 21 to the distillate collector 9. The solvent vapor condensate from the collector 24 is returned to the reactor 1 by the pump 23.

Under stationary conditions of a continuous process of suspension polymerization, the average yield was 33,000 g _PE / g _CAT . UHMWPE powder has a bulk density of 0.16 g / cm ³ and an intrinsic viscosity of 27.4 dl / g, contains particles with sizes of 15 ÷ 80 μm, the yield of the soluble fraction of polyethylene (waxes) was 0.042 wt.%, Which satisfactorily corresponds to the same parameters of the example one.

Example 13. Ethylene suspension polymerization was carried out under conditions similar to Example 1, with the difference that methylcyclohexyl dimethoxysilane was added to the cocatalyst (triethylaluminium) in a molar ratio Al / Si = 10. 250 g of UHMWPE was obtained having [η] = 27.6 dl / g. During the polymerization, the activity of the catalyst is stationary and amounts to 3980 g _PE / (g _CAT · h · atm). The low molecular weight fraction of polyethylene in the composition of heptane is absent.

Example 14. The slurry polymerization of ethylene is carried out under conditions similar to Example 13, except that a solvent, comprising (example 12) 10 wt.% Toluene and 40 wt.% Methylcyclohexane. 248 g of UHMWPE are obtained having [η] = 28.5 dl / g. During the polymerization, the activity of the catalyst is stationary and amounts to 3950 g _PE / (g _CAT · h · atm). The output of the low molecular weight fraction of polyethylene was 0.06 wt.%.

Example 15. Suspension polymerization of ethylene is carried out under conditions similar to example 13, with the difference that instead of methylcyclohexyl dimethoxysilane, 2,6-dimethylpyridine is used with a molar ratio of Al / (2,6-dimethylpyridine) = 10. 245 g of UHMWPE having [η ] = 26.3 dl / g. During the polymerization, the activity of the catalyst is stationary and amounts to 3900 g _PE / (g _CAT · h · atm). The low molecular weight fraction of polyethylene in the composition of heptane is absent.

Example 16. The slurry polymerization of ethylene is carried out under conditions similar to Example 15, except that a solvent, comprising (example 12) 10 wt.% Toluene and 40 wt.% Methylcyclohexane. 242 g of UHMWPE are obtained having [η] = 26.7 dl / g. During the polymerization, the activity of the catalyst is stationary and amounts to 3850 g _PE / (g _CAT · h · atm). The output of the low molecular weight fraction of polyethylene was 0.07 wt.%.

Example 17. Suspension polymerization of ethylene is carried out under conditions similar to example 12, with the difference that instead of triethylaluminum, an organoaluminum compound of the composition AlR n Cl m is used, where: n = 2.8 and m = 0.2. 227 g of UHMWPE are obtained having [η] = 26.9 dl / g. During the polymerization, the activity of the catalyst is stationary and amounts to 3600 g _PE / (g _CAT · h · atm). The yield of the low molecular weight fraction of polyethylene was 0.02 wt.%.

Example 18. Ethylene suspension polymerization was carried out under conditions similar to Example 1, with the difference that instead of triethylaluminum, an organoaluminum compound of the composition Al (C ₂ H ₅ ) ₂ Cl was used. 135 g of UHMWPE are obtained having [η] = 28.8 dl / g. During the polymerization, the activity of the catalyst is stationary and amounts to 2150 g _PE / (g _CAT · h · atm). The low molecular weight fraction of polyethylene in the composition of heptane is absent.

Example 19. Ethylene suspension polymerization was carried out under conditions similar to Example 17, with the difference that methylcyclohexyl dimethoxysilane was added to the cocatalyst (triethylaluminium) in an atomic ratio Al / Si = 20, and heptane was used as the solvent. 224 g of UHMWPE are obtained having [η] = 27.5 dl / g. During the polymerization, the activity of the catalyst is stationary and amounts to 3550 g _PE / (g _CAT · h · atm). The low molecular weight fraction of polyethylene in the composition of heptane is absent.

Example 20. The slurry polymerization of ethylene is carried out under conditions similar to Example 1, with the difference that the polymerization temperature is 70 ^° C to give 390 g of UHMWPE having [η] = 21,1 dl / g. During the polymerization, the activity of the catalyst is stationary and amounts to 6200 g _PE / (g _CAT · h · atm). The output of the low molecular weight fraction of polyethylene was 0.07 wt.%.

Example 21. The slurry polymerization of ethylene is carried out under conditions similar to Example 12 with the difference that the polymerization temperature is 70 ^° C to give 378 g of UHMWPE having [η] = 21,7 dl / g. During the polymerization, the activity of the catalyst is stationary and amounts to 6000 g _PE / (g _CAT · h · atm). The output of the low molecular weight fraction of polyethylene was 0.2 wt.%.

Example 22. Suspension polymerization of ethylene is carried out under conditions similar to example 20, with the difference that methylcyclohexyl dimethoxysilane is added to the cocatalyst (triethyl aluminum) in an atomic ratio Al / Si = 20. 375 g of UHMWPE having [η] = 24.7 dl are obtained. g. In the course of polymerization, the activity of the catalyst is stationary and amounts to 5950 g _PE / (g _CAT · h · atm). The yield of the low molecular weight fraction of polyethylene was 0.02 wt.%.

Example 23. Suspension polymerization of ethylene is carried out under conditions similar to example 22, with the difference that a solvent containing (similar to example 12) 10 wt.% Toluene and 40 wt.% Methylcyclohexane is used. 370 g UHMWPE is obtained having [η] = 25.4 dl / g. During the polymerization, the activity of the catalyst is stationary and amounts to 5900 g _PE / (g _CAT · h · atm). The yield of the low molecular weight fraction of polyethylene was 0.035 wt.%.

Example 24. The suspension copolymerization of ethylene and butene-1 is carried out under conditions similar to example 1, with the difference that instead of ethylene, a gas mixture of ethylene and butene containing 4 vol.% Butene-1 is used. In addition, up to 15 vol% of the total comonomer pressure is introduced into the reactor before polymerization begins. The copolymerization was carried out under stationary conditions at ⁵⁰ ° C, a pressure of 0.3 MPa for one hour. 45 g of a copolymer containing 7 wt.% Butene units and having a melt flow rate of 0.12 g / 10 min are obtained.

Example 25. The suspension copolymerization of ethylene and hexene-1 is carried out under conditions similar to Example 1, with the difference that the liquid phase of the reactor prior to loading of the solid component in the countercurrent ethylene hexene-1 were added to a concentration of 3 wt.% With respect to the solvent. The copolymerization was carried out under stationary conditions at ⁵⁰ ° C, ethylene pressure of 0.3 MPa for one hour. During copolymerization, the concentration of hexene-1 in the liquid phase of the reactor is maintained constant by additional dosage of hexene-1 in the reactor according to the chromatographic analysis of samples of the liquid phase of the reaction medium. 55 g of a copolymer containing 1.9% by weight of hexene units are obtained.

Example 26 uses a solid catalyst component prepared by us in accordance with the prototype method [RF 2243237, IPC C 08 F 4/16, 2004]. A prototype UHMWPE, obtained in the presence of a catalyst, as claimed in the prototype, was tested in the conditions of the technology of gel-forming fibers.

Example 26. Polymerization of ethylene was carried out according to conditions described in Example 1, prototype: in a 2 liter reactor charged with 1000 ml of hexane, 1 mmol of triethylaluminum, 0.015 g of the solid catalyst component (in terms of 0.01 mmol of titanium). The polymerization is carried out at an ethylene pressure of 0.1 MPa and a temperature of 70 ^about C for one hour. 40 g of UHMWPE with an inherent viscosity of 22.6 dl / g are obtained. In the course of polymerization, a stationary activity of the catalyst is observed, equal to 2700 g _PE / (g _KAT · h · atm). The bulk density of the powder is 0.37 g / cm ³ , the average particle size of 140 microns. The output of the soluble fraction of polyethylene was 0.05 wt.%. When testing a prototype UHMWPE (obtained under the conditions of a pilot installation, similar to example 26) in the technology of gel molding it was found:

a) the quality of the molding is unstable;

b) the maximum multiplicity of stable thermal elongation does not exceed 34;

c) the fiber characteristics are not satisfactory enough: the tensile strength was 235 cN / m, and the modulus of elasticity is 8300 ρ ^-1 cN / m.

The examples given clarify the invention without limiting it.

Thus, the present invention, based on the experience of cooperation between developers of UHMWPE synthesis technology and UHMWPE gel-forming technology (preparation of spinning solutions, gel-forming and subsequent orientation drawing of fibers), increases the efficiency of the technology for producing high-modulus fibers based on ultra-high molecular weight polyethylene.

The proposed catalyst, methods for producing a solid catalyst component and UHMWPE solve the problems:

- increasing the specific activity of the solid component of the catalyst and the molecular weight of UHMWPE;

- a method for producing a solid component of a catalyst provides high dispersion and an optimal texture of its particles and the corresponding characteristics of UHMWPE powder (with a high specific polymer yield), which minimizes the time required to prepare homogeneous spinning solutions in the process of gel forming and thereby minimize the degree of degradation properties of the dissolved polymer due to thermal degradation and the effects of mechanical shear stresses;

- the method for producing UHMWPE through targeted adjustment of the composition of the cocatalyst (the use of electron-donating compounds) and the composition of the solvent (the use of aromatic and naphthenic hydrocarbons) solves the problems of further increasing the average molecular weight of polyethylene, adjusting the molecular weight distribution and minimizing the fraction of low molecular weight fraction in the composition of the obtained UHMWPE; at the same time, the orientational drawing and strength properties of the obtained fibers are improved and crazing is reduced (the formation of a network of thin cracks on the fiber).

Table 1 - Characteristics of the ratios of the load of the reagents in the synthesis of the solid component.

No.
an example Molar relations in the preparation of the solution -
(ethanol): (triethylaluminum): (silicon compound): (heptane) The molar ratio of C ₂ H ₅ OH / Mg in the interaction of the alcohol solution with magnesium metal The atomic ratio of Ti / Mg during the first treatment of TiCl ₄ The atomic ratio of Ti / Mg in the second treatment with TiCl ₄ The given activity per unit mass of the solid component ^*) ,
__ g _PE __
g _CAT · h · atm Characteristics of UHMWPE Powders Exit,
g _PE /
r _cat Bulk density,
g / cm ³ Particle size
μm one 6.5: 0.1: 0.1: 0.7 6.5 10 8 4050 36450 0.14 15 ÷ 70 2 7.5: 0.15: 0.15: 1.5 6.5 8 6 3850 34650 0.16 20 ÷ 80 3 6.5: 0.1: 0.1: 0.7 6.5 9 5 3100 27900 0.25 10 ÷ 150 four 7.5: 0.15: 0.15: 1.5 6.5 7 8 2800 25200 0.32 5180 5 7.5: 0.15: 0.15: 1.5 7.5 10 8 3980 35820 0.15 15 ÷ 70 6 7.5: 0.15: 0.15: 1.5 7.5 8 6 3750 33750 0.17 fifteen 7 6.5: 0.1: 0.1: 0.7 7.5 9 5 2700 24300 0.31 5 ÷ 220 8 7.5: 0.15: 0.15: 0.7 7.5 7 8 2650 23850 0.35 10 9 7.5: 0 .: 0.15: 1.5 6.5 8 6 3800 34650 0.26 5 10 7.5: 0.15: 0: 1.5 7.5 8 6 3770 33930 0.25 10

^*) The values correspond to the activity of a polymerization temperature of 50 ^{° C,}

Table 2 - Characteristics of the composition of the cocatalyst suspension polymerization of ethylene according to the examples.

No.
at
measure The reduced activity of the catalyst,
____ g _PE __
g _cat · h · atm Intrinsic viscosity
dl / g The output of the soluble fraction of polyethylene (waxes),
wt.% Suspension Polymerization Conditions Temperature,
^about C The composition of socialization ^*)
AlRnClm · k D The composition of the solvent ^**) , wt.% Coefficients m and k
D - methylcyclohexyl dimethoxysilane (2,6-dimethylpyridine) Toluene Methylcyclohexane m k  one 4050 24.1 0.04 fifty 0 0 0 0 eleven 4020 24.4 0.13 fifty 0 0 10 40 12 4000 27,2 0,043 fifty 0 0.05 6 35 12 (p) 3700 27.4 0,042 fifty 0 0.05 6 35 13 3980 27.6 0 fifty 0 0.1 0 0 fourteen 3950 28.5 0.06 fifty 0 0.1 10 40 fifteen 3900 26.3 0 fifty 0 (0,1) 0 0 16 3850 26.7 0,07 fifty 0 (0,1) 10 40 17 3600 26.9 0.02 fifty 0.2 0 10 40 eighteen 2150 28.8 0 fifty one 0 0 0 19 3550 27.5 0 fifty 0.2 0.05 0 0 twenty 6200 21.1 0,07 70 0 0 0 0 21 6000 21.7 0.2 70 0 0 10 40 22 5950 24.7 0.02 70 0 0.05 0 0 23 5900 25,4 0,035 70 0 0.05 10 40

^*) Co-catalyst - Al (C ₂ H ₅ ) nClm · kD, where R is an ethyl radical; D is an electron-donating compound: methylcyclohexyl dimethoxysilane or 2.6-dimethylpyridine; n + m = 3; 0 ≤ m ≤ 1.5; 0 ≤ k ≤ 0.5; k values given without parentheses refer to silane; k values given in parentheses refer to 2,6-dimethylpyridine.

^{**) The} solvent includes: toluene and methylcyclohexane, the rest is aliphatic hydrocarbons (C ₇ fraction) up to 100%.

Table 3 - Characteristics of UHMWPE powders and gel-forming technology and orientation drawing.

No.
at
measure Gel forming process indicators Fiber Characteristics * ⁾ UHMWPE output
g _PE / g _CAT Characteristics of UHMWPE Powders Molding quality The maximum ratio of stable thermal traction Tensile strength
cn / m Elastic modulus,
ρ ^-1 · 1 sN / m
(or kgf / mm ² ) Intrinsic viscosity
dl / g Bulk density,
g / cm ³ Particle sizes of UHMWPE powders
μm one Stable 48 280 9800 36450 24.1 0.14 15 ÷ 70 four not stable. 35 250 8700 25200 18.5 0.32 5 ÷ 180 5 Stable 48 280 9800 35800 24.0 0.15 fifteen 6 Stable 47 270 9700 33750 23.8 0.17 15 ÷ 90 8 not stable. 37 240 8200 23850 17.8 0.35 10 ÷ 300 9 not stable. 32 230 8100 34200 22.9 0.26 5 ÷ 250 10 not stable. 41 235 8000 33750 22.4 0.25 10 ÷ 200 eleven Stable fifty 285 9800 36180 24.4 0.14 15 ÷ 70 12 (p) Stable 55 300 10,000 33300 27.4 0.14 15 ÷ 70 fourteen Stable 57 305 10,000 35500 28.5 0.14 15 ÷ 70 eighteen Stable 57 310 10100 19350 28.8 0.14 15 ÷ 70 twenty Stable 39 240 8200 55,000 21.1 0.14 15 ÷ 70 23 Stable fifty 290 9800 53000 25,4 0.14 15 ÷ 70

* ⁾ Tensile strength, cN / m (centinewton / tex); 1 cN / m = ρ · 1 kgf / mm ² = 1 rkm,

where ρ, g / cm ³ is the fiber density; rkm - a conventional unit (in km), characterizing the length of the fiber at which it breaks under the action of its own gravity.

The modulus of elasticity, ρ ^-1 · 1 cN / m (or kgf / mm ² ) is an indicator characterizing the magnitude of the applied stress at a relative fiber elongation of 1%.

Claims (8)

1. A catalyst for the polymerization and copolymerization of ethylene, including an organoaluminum compound and a solid component, representing 12–15 wt.% Of catalytically active titanium compounds per 85 ÷ 88 wt.% Of a magnesium dichloride support and obtained by the interaction of magnesium metal, ethanol, aluminum, silicon and titanium compounds, characterized in that as a solid component it includes particles containing titanium, magnesium, chlorine, aluminum and silicon in an atomic ratio of 1.0: 6.0: 16.0: 0.07: 0.02 to 1 , 0: 7.0: 18.0: 0.06: 0.01, respectively, in the following ratio of catalyst components, parts by weight: organoaluminum compound 40 ÷ 200 solid component one 2. The catalyst according to claim 1, characterized in that as the organoaluminum compound, a compound of the composition is used (ALRnCLm) kD, where R is a hydrocarbon radical containing 2 ÷ 4 carbon atoms; D is an electron-donor compound selected either from the class of substituted dialkyl derivatives of pyridine of the formula 2,6-dialkylpyridine or from the class of organosilicon esters of the formula R _x 'R _y "Si (OR''') _4-xy , (where R '' 'are alkyl radicals containing 1 ÷ 5 carbon atoms; R', R "are alkyl, cycloalkyl or aromatic hydrocarbon radicals containing 1 ÷ 6 carbon atoms; x = 1 ÷ 3; x + y = 2 or 3; x, y are natural numbers); n, m, k are stoichiometric coefficients related by the relations 0≤m≤1.5; n + m = 3; k = 0 ÷ 0.5. 3. The catalyst according to claim 2, characterized in that ethyl or isobutyl groups are included in the composition of the organoaluminum compound as hydrocarbon radicals R. 4. The catalyst according to claim 2, characterized in that 2,6-dimethylpyridine and (or) methylcyclohexyl dimethoxysilane are used as the electron donor compound. 5. The method of producing a solid catalyst component according to claim 1, characterized in that a heptane solution of triethyl aluminum and methylcyclohexyl dimethoxysilane in a molar ratio ethanol: triethyl aluminum: methylcyclohexyl dimethoxysilane: heptane from 6.5: 0.1: 0 is dosed into dehydrated ethanol at 10 ° C. 1: 0.7 to 7.5: 0.15: 0.15: 1.5, respectively, to the resulting solution metal magnesium is added in a molar ratio ethanol: magnesium = 6.5: 1.0 ÷ 7.5: 1, 0 and carry out for 10 h the reaction of the interaction of magnesium metal with the components of the solution at 70 ° C with the formation of suspensions zi of magnesium and aluminum alkoxides in ethanol, dose the resulting suspension at a temperature of 0 ÷ 20 ° C into a liquid phase containing titanium tetrachloride in an amount determined by the atomic ratio Ti / Mg = 8 ÷ 10, and heptane in an amount determined by the molar ratio TiCL ₄ / C ₇ H ₁₆ = 2/1, heat the resulting mixture for two hours at 100 ° C, isolate the solid product and re-treat it at 100 ° C for two hours with a mixture of titanium tetrachloride and heptane with an atomic ratio of Ti / Mg = 6 ÷ 8 and a molar ratio of TiCL ₄ / C ₇ H ₁₆ = 2/1, a solid product is isolated, containing 3.2 wt.% titanium. 6. A method of producing ethylene polymers (copolymers) of ultrahigh molecular weight by suspension polymerization (copolymerization with alpha-olefins) of ethylene at a temperature of 0 ÷ 100 ° C and an ethylene pressure of 0.1 ÷ 5.0 MPa, characterized in that the polymerization or copolymerization of ethylene carried out in the presence of a catalyst according to claim 1 in a continuous or batch mode in a solvent medium containing a mixture of aliphatic, aromatic and (or) naphthenic hydrocarbons. 7. The method according to claim 6, characterized in that during the copolymerization of ethylene, propene-1, butene-1, hexene-1, or mixtures thereof are used as comonomers. 8. The method according to claim 6, characterized in that the solvent contains toluene up to 10 wt.% And (or) naphthenic hydrocarbons (methylcyclopentane, cyclohexane and methylcyclohexane) - up to 50 wt.%.

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