Tube, having high heat resistance and use of polyethylene composition in making said tube

FIELD: chemistry.

SUBSTANCE: composition contains basic polyethylene resin making up at least 90 wt % of all the composition and having time to failure equal to at least 250 hours measured according to ISO 1167 at 95°C and 4.3 MPa. The basic resin contains a copolymer of ethylene with alpha-olefin, containing 4-20 carbon atoms, as fraction (A) and a homopolymer of ethylene or copolymer of ethylene with alpha-olefin, containing 4-20 carbon atoms, as fraction (B). Fraction (A) has lower molecular weight than fraction (B). Density of the basic resin is lower than 940 kg/cm3, and melt flow rate (MFR5) at 190°C/5.00 kg is equal to at least 0.20 g/10 min.

EFFECT: higher pressure resistance at high temperature, as well as improved flexibility of the tube.

12 cl, 1 tbl, 2 ex

 

The present invention relates to a pipe with high heat resistance, made of a polyethylene composition comprising a polyethylene resin obtained by the polymerization method in the presence of a catalyst with a single center of polymerization on the metal (SSC), and to a method for producing such pipe.

Pipes, in particular pressure pipes, used in various purposes such as transportation of drinking water, wastewater, as well as in various industrial purposes, for transportation of gas and so on.

Depending on the strength of the polymer polyethylene pipes for pressure systems can be classified into several categories, such as RE, RE or RA. The higher the numerical value, the longer the service life at high pressure.

However, polyethylene has limited resistance to pressure at elevated temperature. It is especially difficult to combine good resistance to pressure at elevated temperatures with high flexibility of materials for the manufacture of pipes.

The classic technique for improving the pressure resistance of the pipe at an elevated temperature is cross stitching material. However, the low purity of the cross-linked resin may be an obstacle for their use in pipes that are in contact with drinking water and/or food. Moreover, the utilization of cross-linked material is difficult. Thus, thermoplastic material alternatives would be preferable, if the technical characteristics, such as resistance to pressure at elevated temperatures could be significantly improved. There have been many attempts to develop such materials.

Currently, the best available polyethylene pressure pipes receive the multistage method using the catalysts of the Ziegler-Natta. The density of the polyethylene resin to achieve high resistance to high pressure. However, the high density provides high rigidity, which is a disadvantage, for example, when the pipe installation.

Were also conducted intensive research polyolefin resins produced by using metallocene catalysts or catalysts with a single center of polymerization on the metal, but still such resins have not received widespread commercial implementation. The main areas where they were implemented resin obtained by using catalysts with a single center of polymerization on the metal, are a film or extrusion coating, as described, for example, in WO 03/066699. The films described herein have excellent mechanical properties and excellent adhesive power.

However, it is known that the catalytic activity of catalysts with a single center of polymerization N. the metal is moderate, the highest activity was achieved in the areas of medium to low density.

In addition, the resin pressure pipe obtained by using catalysts with a single center of polymerization on the metal, known from the field of technology, as described, for example, in WO 02/34829 traditionally have density higher than 940 kg/m3. As a result, the flexibility of the pipe is relatively low.

In addition, for the production of pressure pipes you need to use a polyethylene composition has suitable speed melt flow and molecular weight distribution to ensure a good capacity for technological processing composition during the extrusion process.

Therefore, the aim of the present invention is the provision of a pipe having improved resistance to pressure at an elevated temperature while increasing the flexibility of the pipe.

So, it has been unexpectedly found that such a tube can be obtained by using a polyethylene composition containing the base resin, which was obtained using a catalyst with a single center of polymerization on the metal, which has a density of less than 940 kg/m3and P5equal to at least 0.2 g/10 minutes

Thus, in the present invention proposed pipe made from polyethylene comp the positions, containing polyethylene core resin, which contains

A. a copolymer of ethylene with an alpha olefin containing From4-C20carbon atoms, as a fraction (a) and

b. a homopolymer of ethylene or copolymer of ethylene with an alpha olefin containing C4-C20carbon atoms as a fraction (In), fraction (A) has a lower molecular weight than fraction (B), where the PE the main resin obtained by the polymerization method, in which the catalyst with a single center of polymerization on the metal (SSC) used in the polymerization of at least one of the fractions (a) and (b), and the main resin has

(i) a density less than 940 kg/m3and

(ii) P5(the flow rate of the melt) at 190°C/5,00 kg, equal to at least 0.20 g/10 min,

and the polyethylene composition has a time to failure of at least 250 hours, measured according to ISO 1167 at 95°C and 4.3 MPa, and SHI(of 2.7/210)(index reduce the viscosity shear) polyethylene resin base is less than 20.

Also proposed the use of specified composition to obtain a pipe.

As demonstrated below, the invention enables to produce a more flexible tubes, however, meet the requirements of high pressure resistance at elevated temperatures.

Therefore, for example, improved flexibility of the pipes according to the invention p is positioned them easier to bend and as a consequence, more easily collapse rings. This gives the advantage that the pipe installation much easier.

The term "principal resin" means any and all many of polymer components in the polyethylene compositions of the pipe according to the invention, usually making up at least 90 wt.% of the total composition. Preferably, the main resin consists of fractions (a) and (b)may additionally including prepolymers faction in the amount equal to 20 wt.%, preferably up to 10 wt.%, more preferably up to 5 wt.% of the total resin base.

The density of the resin base is in the range of mean values, i.e. less than 940 kg/m3preferably less 939 kg/m3more preferably in the range of equal to from 910 to less than 940 kg/m3even more preferably in the range of equal to from 915 to less than 940 kg/m3and most preferably in the range of equal to from 920 to less 939 kg/m3that is measured according to ISO 1183.

Despite the fact that the density of the resin base at 5-10 kg/m3compared with traditional resin pipe according to the invention withstand the demands of high temperature.

The rate of flow of the melt (P) and the ratio of the melt index (FRR) are important properties of polyethylene resin base, because CTP and FRR are the yield and,therefore, the ability to process the polymer. The higher the flow velocity of the melt, the lower the viscosity of the polymer.

In the present invention a polyethylene main resin should have a CTP5equal to at least 0.20 g/10 min, preferably equal to at least 0.5 g/10 min and most preferably equal to at least 1.3 g/10 min CTP5polyethylene resin base is typically less than 7.0 g/10 min, more preferably is 3.5 g/10 min or less and most preferably 1.5 g/10 min or less.

In addition, it is preferable that polyethylene main resin has a CTP5from 0.06 to 10 g/10 min, more preferably from 0.1 to 5.0 g/10 min, even more preferably from 0.1 to 1.0 g/10 min and most preferably from 0.1 to 0.5 g/10 minutes

Moreover, for applications of pipe important good ability polyethylene composition to technological processing. Large molecular mass needed to meet the requirement for good resistance to pressure at elevated temperatures and low creep, however, processing of such resins with high molecular weight more difficult. Improved ability to process reach multimodal execution of the main resin. This means that in the composition used for pipes according to the invention, a CR who are present at least one low molecular weight fraction (A), giving an easier ability to process, and one high molecular weight fraction (C), which provides mechanical strength.

Typically, a polyethylene composition comprising at least two polyethylene fractions, which were obtained under various conditions of polymerization, leading to different (srednevekovym) molecular mass fractions, referred to as "multimodal". The prefix "multi" refers to the number of different polymer fractions that make up the composition. For example, the composition consisting only of the two factions, called "bimodal".

The shape of the distribution curve of molecular weight, i.e. the graph of the weight of the polymer fraction as a function of its molecular weight, such multimodal polyethylene will show two or more maximum or at least distinctly broadened in comparison with the curves for the individual fractions.

For example, if the polymer is produced by a sequential multi-stage process using a reactor connected in series and using different conditions in each reactor, the polymer fractions obtained in the different reactors will each have their own molecular weight distribution and srednevekovoy molecular weight. When recording the curve of the molecular mass distribution that the second polymer, individual curves from these fractions are superimposed on the curve of the molecular-mass distribution of the final polymer product, usually resulting in obtaining a curve with two or more distinct peaks.

The PE the main resin of the present invention is a multi-modal or more preferably bimodal polyethylene main resin containing fractions (A) and (B)as defined above, where the fraction (A) has a lower molecular weight than fraction (B).

In a preferred variant embodiment, in which the basic resin consists of fractions (A) and (B), may not be present preprimary fraction in number, as defined above.

The term molecular weight used in the present description, refers to srednevekovoy molecular mass Mw.

The PE the main resin of the present invention preferably has a molecular weight distribution (MWD), is equal to from 5 to 25, more preferably equal to from 5 to 20 and most preferably equal to from 5 to 15.

It is preferable that the ethylene copolymer (A) has a density equal to less than 945 kg/m3more preferably less than 940 kg/m3. The preferred density range for the copolymer of ethylene (A) ranges from 920 to less than 945 kg/m3more preferably from 925 to less than 940 kg/m3 .

In addition, in the present invention, the fraction (A) is a copolymer of ethylene and fraction (B) may be Homo - or copolymer of ethylene. However, it is preferable that the component (B) is a copolymer of ethylene.

Used comonomers both factions may be the same or different.

As comonomers, you can use different alpha-olefins with C4-C20carbon atoms, however, the comonomers preferably represents C4-C20alkene selected from the group consisting of 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-Heptene, 1-octene, 1-mission 1-eicosene. In a particularly preferred variant of embodiment of comonomer is a 1-butene and/or 1-hexene.

The PE the main resin of the present invention may also contain tertiary polymer, which means that at least one of the fractions (A) and (B) consists of ethylene and two different comonomeric links.

It is preferable that the component (B) is a copolymer of ethylene and an applied comonomer is an alpha-olefin with 4, more preferably 6 or more carbon atoms, more preferably represents 1-hexene or 1-octene.

The number of co monomer used in fraction (A), is preferably from 0.1 to 3.0 mol.%, more preferably from 0.2 to 2,mol.%, even more preferably from 0.5 to 1.5 mol.%.

The number of co monomer used in fraction (B), is preferably from 0.1 to 2.0 mol.%, more preferably from 0.1 to 1.5 mol.%, even more preferably from 0.2 to 1.0 mol.%.

Moreover, the flow velocity of the melt CTP2(190°C/2, 16 kg) fraction (A) preferably ranges from 10 to 300 g/10 min, more preferably from 10 to 200 g/10 min and most preferably from 50 to 140 g/10 minutes

Previously it was known that to obtain multimodal, in particular bimodal, olefinic polymers such as polyethylene main resin of the present invention, it is possible to use two or more reactors or zones connected in series, as described in EP 517868 that fully incorporated into the present description by reference.

According to the present invention the main stage polymerization is preferably carried out in combination, a suspension polymerization/gas-phase polymerization. Suspension polymerization is preferably carried out in a so-called circulating reactor.

Optional and mainly the main stages of polymerization can be preceded by preliminary polymerization and in this case get prepolymer in number, as described above, most preferably in a quantity of from 1 to 5 wt.% from the total number is and polymers. Prepolymer can be a Homo - or copolymer of ethylene.

If there is the preliminary polymerization, in this case the whole amount of the catalyst is preferably loaded into the first reactor prior to polymerization and pre-polymerisation process is carried out as suspension polymerization. Such polymerization leads to get more small particles in the subsequent reactors and to receive at the end of a more homogeneous product. Typically, this technique results in a mixture of multimodal polymer by the polymerization using the catalyst of the present invention using a catalyst with a single center of polymerization on the metal.

The catalyst with a single center of polymerization on the metal used in examples of the present invention, has been disclosed in EP 1462464, example 5, the catalyst 3.

In the method according to the invention to obtain a resin base polymer of the composition according to the invention at least a fraction (A) or fraction (B) obtained during the polymerization reaction in the presence of a catalyst with a single center of polymerization on the metal. For example, fraction (A) or an alternative fraction (B) can be obtained in the presence of a catalyst with a single center of polymerization on the metal, and the fraction (B) or alternative fraction (A) can be obtained in the presence of a catalyst of the Ziegler-Natta.

However, it is preferable that both fractions (A) and (B) are obtained in the presence of a catalyst with a single center of polymerization on the metal.

In addition, it is preferable that the fraction (A) and fraction (B) is subjected to polymerization in the presence of the same catalyst with a single center of polymerization on the metal.

In the production of polyethylene resin base according to the present invention it is preferable that the fraction (A) obtained in the circulation reactor under certain conditions in relation to hydrogen, the concentration of monomer and co monomer, temperature, pressure and so on.

In addition, it is preferable that the fraction (B) obtained in gas-phase reactor.

Even more preferably, after the polymerization of the component (A)comprising the catalyst is transferred into a reactor, preferably a gas phase reactor, where the fraction (B) obtained when other conditions.

The resulting end product consists of a homogeneous mixture of the polymers of the two main reactors, with different curves of the molecular weight distribution of these polymers together form the curve of the molecular mass distribution, which has a broad maximum or two maxima, i.e. the final product is a bimodal polymer mixture.

Thanks to the flexibility thus obtained reaction conditions, it is most preferable that the floor is merisalu carried out in the reactor prior to polymerization/circulation reactor/gas-phase reactor. It is preferable that the conditions of polymerization in the preferred three-stage method chosen so that the fraction (A) receive at one stage, preferably the second reactor, while the fraction (B) get to another stage, preferably in the third reactor. The order of these stages, however, may be reversed.

In the present invention it is preferable that the preliminary polymerization occurs at a temperature of from 40 to 70°C, more preferably from 50 to 65°C, and preferably at a pressure equal to from 5.0 to 7.0 MPa, more preferably equal to from 5.5 to 6.5 MPa.

In the second reactor, the polymerization temperature is preferably from 60 to 100°C, more preferably from 70 to 90°C, and preferably at a pressure equal to from 4.0 to 7.0 MPa, more preferably equal to from 5.0 to 6.0 MPa.

In the third reactor temperature is preferably from 60 to 105°C, more preferably from 70 to 90°C, and preferably at a pressure equal to from 1.0 to 4.0 MPa, more preferably equal to from 1.5 to 2.0 MPa.

The mass ratio between the two fractions (A) and (B)obtained in the second and third reactor is preferably from 60:40 to 40:60, more preferably from 55:45 to 45:55.

Plastic composition from which fabricated pipe according to the invention may also contain additives, such as to the where it is refuelled, facilitating technological processing, antioxidants, pigments, UV stabilizers and the like. Typically, the amount of these additives is 10 wt.% or less calculated on the total composition.

The pipe according to the present invention can be manufactured in any conventional manner, preferably by extrusion of the polyolefin composition in the extruder. This technique is well-known specialist in this field.

The pipe according to the present invention shows good resistance to voltage, and high flexibility.

Index reduce the viscosity shear (SHI) represents the ratio of the viscosity of the polyethylene resin base at different shear stresses and can serve as a measure of the breadth of the molecular mass distribution. In the present invention the shear stress 2,7 kPa and 210 kPa and 5 kPa and 300 kPa are used to determine SHI polyethylene resin base. The definition and the measurement conditions are described in detail in WO 00/22040 on page 8, line 29 to page 11, line 25.

The PE the main resin is preferably SHI(of 2.7/210)equal to less than 20, more preferably equal to less than 15 and most preferably equal to less than 10. It is preferable that SHI(of 2.7/210)is in the range from 1 to less than 20.

It is also preferable that SHI(5/300)is m is Nise 35, more preferably less than 30 and most preferably less than 25. The preferred range SHI(5/300)is from 5 to less than 35.

In addition, the viscosity at a shear stress equal to 0.05 kPa (eta0,05). plastic resin base, preferably is at least 15000 PA·s, more preferably at least 18000 PA·s, and most preferably at least 20000 PA·S.

In addition, the viscosity at a shear stress equal to 0.05 kPa (eta0,05), a polyethylene resin base, preferably less than 80000 PA·S.

Test for impact strength according to Charpy at low temperature assesses the impact strength and, therefore, provides an opportunity to assess the resistance to the rapid spread of the cracks (RCP).

In a preferred variant embodiment of the present invention the polyethylene composition of the pipe has impact strength by Sharlee at 0°C, equal to at least 8 kJ/m2most preferably equal to at least 10 kJ/m2measured according to ISO 179.

Resistance to rapid crack penetration polyethylene composition according to the present invention defined by the method, named S4 (test steady state in a shorter version), which was developed at the Royal College, London, and is described in ISO 13477:1977 (E). Pipe this is the invention preferably reaches the critical temperature, i.e. the values of the RCP-S4, is equal to +2°C or less, more preferably equal to +1°C or less.

Resistance to the rapid spread of the crack are determined according to ISO 13479:1997 as the number of hours during which the pipe with cut withstand a certain pressure at a certain temperature before destruction.

Additionally, the time to fracture of the polyethylene composition at 95°C and 4.3 MPa according to ISO 1167 is preferably at least 250 hours, more preferably at least 300 hours, most preferably at least 350 hours

The modulus of elasticity in bending of the polyethylene composition is preferably less than 700 MPa, more preferably less than 650 MPa, and most preferably less than 600 MPa, as measured according to ISO 178. It is preferable that the modulus of elasticity in bending of the polyethylene composition is 300 MPa or more, more preferably 400 MPa or more.

The modulus of elasticity of the pipe according to the present invention was determined according to ISO 527. Polymer composition according to the present invention preferably has a modulus of elasticity of from 400 to 900 MPa, more preferably from 425 to 850 MPa, and most preferably from 450 to 800 MPa.

Methods and examples

The rate of flow of the melt (CTP)

P determined according to ISO 1133 and is expressed in g/10 min. For polyethylene resins note the following temperature equal to 190°C. CTP is determined at different loadings such as 2,16 kg (CTP2; ISO 1133), 5 kg (CTP5; ISO 1133) or 21.6 kg (CTP21; ISO 1133). The ratio of the melt index, FRR, represents the ratio between CTPMassaand CTPMassai.e. FRR21/5means the ratio between CTP21and CTP5.

Molecular mass

Srednevekovoy molecular mass Mwand molecular weight distribution (MWD=Mw/Mnwhere Mnrepresents srednekamennogo molecular mass Mwrepresents srednevekovoy molecular weight) is measured based on ISO 1014-4:2003. Used appliance Waters 150CV+ with column 3×HT&E styragel from Waters (divinylbenzene) and trichlorobenzene (TCB) as solvent at 140°C. Set the columns were calibrated using universal calibration standards polystyrene (PS) with a narrow molecular weight distribution (constant Mark-Hovinga K: 9,54·10-5and a: 0,725 for PS, and K: 3.9·10-4a: 0,725 for PE (polyethylene)). The ratio of Mwand Mnrepresents a measure of the breadth of distribution, because each influences the other end of the "population".

The rapid spread of cracks (S4)

Resistance to rapid crack penetration (RCP) pipe are determined according to ISO 13477 (E). According to RCP-S4 method tested is subjected to a pipe which has about ewww length not less than 7 pipe diameters. The external diameter of the tube is approximately 110 mm or more, and the thickness of its wall is about 10 mm or more. When determining RCP properties of the pipe in connection with the present invention the outer diameter and wall thickness were chosen, respectively, 110 mm and 10 mm, while the outer part of the pipe is at ambient pressure (atmospheric pressure)inside the pipe is under pressure and the internal pressure in the pipe is maintained at a constant level equal to 0.5 MPa overpressure. The pipe and surrounding equipment thermostatic to a predetermined temperature. Several discs were fixed on the rod inside the tube to prevent the reduction of the compressive load during the test. Blade striker shoots on a clearly defined path toward the pipe closer to its end in the so-called zone of initiation to cause rapidly developing axial crack. In the zone of initiation provided the support piece to prevent unnecessary deformation of the pipe. The test device is adjusted so that the target material is the initiation of cracks and produce a series of tests at different temperatures. Measure the length of the axial cracks for each test in the measuring zone, with a total length equal to 4.5 times the diameter of the pipe, and build a graph of relative ustanovlennoy test temperature. If the crack length exceeds 4 pipe diameter, crack assess how pervasive. If the pipe passes the test at a given temperature, the temperature is successively reduced until reaching the critical temperature (Tcritical), in which the pipe is no longer passes the test.

The pressure test on andrisani pipes

The pressure test on andrisani pipes with a length of 32 mm is carried out according to ISO 1167-3 when 4,3 MPa and 95°C. the Time to failure is determined in hours.

The pressure test on the pipe with cut

The pressure test on the pipe with a cut length of 110 mm is carried out according to ISO 13479.

Test impact strength according to Charpy

Impact strength is defined as Impact Strength according to Charpy according to ISO 179-1 (not instrumental method) or ISO 179-2 (instrumental method).

The modulus of elasticity in bending

The modulus of elasticity in bending are determined according to ISO 178 at a constant speed of 2 mm/min

The modulus of tensile elasticity (E-modulus)

The modulus of tensile elasticity determined according to ISO 527-2 (test example 1B) at a constant speed of 1 mm/min

Rheological parameters

Rheological parameters such as the index to reduce the viscosity of the shear SHI and viscosity, determined using a rheometer, preferably Physica MCR 300 Rheometer production is and Anton the Raag. The definition and measurement conditions are described in detail in WO 00/22040 on page 8, line 29 to page 11, line 25.

Examples

Example 1

In the circulation reactor with a volume of 50 DM3added 32 kg/h of propane and 8.3 g/h of hydrogen. The operating temperature was 60°C, and the working pressure was 6.1 MPa.

The suspension was unloaded from the reactor and transferred into the circulation reactor of 500 DM3. The reactor was operating at 85°C and a pressure of 5.8 MPa. The catalyst with a single center of polymerization on the metal, prepared as described in EP 1462464, Example 5, the catalyst 3, is continuously loaded into the circulation reactor with a flow rate equal to 29 g/min Additional ethylene, 1-butene, the diluent in the form of propane and hydrogen was continuously introduced into the reactor in such a way that the receiving rate of the polymer was 35 kg/h, and CTP2the polymer was 110 g/10 min and density of the polymer was 939 kg/m3.

The suspension is continuously taken out from the reactor to the stage of cleaning, where were removed from the polymer hydrocarbons. The polymer then was transferred into a gas-phase reactor, where the polymerization was continued. The reactor operated at a temperature of 80°C and a pressure of 2.0 MPa. Ethylene, hydrogen and 1-hexene were loaded into the reactor for the production of such conditions to the acquisition rate of the polymer was 34 kg/h, p5the polymer was 1.4 g/10 min, p2the polymer was 0.45 and the/10 min and a density amounted to 936 kg/m 3. The performance of the catalyst was 2.4 kg/g catalyst.

The ratio of the polymer obtained in suspension (reactor 2) and gas-phase (reactor 3) the reactor was 51:49.

The polymer is then mixed with 1500 ppm of calcium stearate and 3000 m D. B225. Properties obtained by mixing the resin are shown in Table 1, which also shows the reaction conditions for obtaining a resin base.

Obtained by blending the material was extrudible into pipes having an external diameter of approximately 110 mm, and a width of about 10 mm, and 32 mm and a width of 3 mm, respectively. The result of the test tube under pressure are shown in Table 1.

Example comparison 1

Resin for pipe received through a three-stage process of circulating the reactor prior to polymerization, followed by first circulating the reactor, and then the gas-phase reactor as described in Example 1. The ratio between the reactor was 2:38:60. In the reactor prior to polymerization is not used comonomer, while 1-butene was used as the co monomer in obtaining low - and high-molecular fraction obtained in the circulation and gas-phase reactor, respectively, in amounts as shown in Table 1, so that the content of 1-butenova of co monomer from the total final polymer was the 2.9 wt.%. Used catalyst type Ziegler-Natta, as disclosed in EP 688794. Resin properties are listed in Table 1.

Received the main resin was introduced into the mixture in the same way as in Example 1, and obtained by blending the material was then extrudible into pipes having an external diameter of approximately 110 mm, and a width of about 10 mm, and a diameter of 32 mm, and a width of 3 mm, respectively. The test result under pressure are also shown in Table 1.

596
Table 1:
UnitExample 1Example comparison 1
The reactor prior to polymerization
Temperature°C6070
PressureMPa6,16.42 per
The ratio of masses between the reactorswt.% 02
Circulation reactor
Temperature°C8585
PressureMPa5,86,4
The concentration of C2mol.%the 5.75,8
The ratio of H2/C2mol/KMOL0,46293
The ratio of C4/C2mol/KMOL92163
The ratio of masses between the reactorswt.%5138
CTP2 g/(10 min)110300
Densitykg/m3939964
ComonomerButene-1Butene-1
Gas-phase reactor
Temperature°C8085
PressureMPa2,01,95
The ratio of H2/C2mol/KMOL020
The ratio of C4/C2mol/KMOL0138
The ratio of C6/C2/sub> mol/KMOL40
The ratio of masses between the reactorswt.%4960
ComonomerHEXEN-1Butene-1
The density of the resin basekg/m3936942,2
The preparation of a mixtureThe extruder JSW CIM90PJSW CIM460P
Consumption when downloadingkg/h217
SEI (specific energy consumption)kW/h277235
Temp is the temperature of melting °C222285
The properties of the prepared mixture resin
The content of hexene-1wt.%1,30
The content of butene-1wt.%1,62,2
CTP2g/(10 min)0,45
CTP5g/(10 min)1,40,45
CTP21g/(10 min)10
Mwg/mol157,000240,000
Mn/sub> g/mol17,2008,600
MWD9,128
The density of the prepared mixture resinkg/m3937,2942,5
SHI(of 2.7/210)8,621,8
SHI(5/300)15,236,5
Eta0,05PA·s2345082250
E-moduleMPa640868
The modulus of elasticity in bendingMPa730
Impact strength at 0°CkJ/m31016
Impact strength at -20°CkJ/m35,9
The pressure test on andrisani pipes with a length of 32 mm
4,3 MPa at 95°Ch406<21
RCP-resistance, Tcritical°C+1

1. Pipe made from polyethylene composition comprising a polyethylene main resin component to at least 90 wt.% from the overall composition, which contains
A. a copolymer of ethylene with an alpha olefin containing From4-C20carbon atoms, as a fraction (a) and
b. a homopolymer of ethylene or copolymer of ethylene with an alpha olefin containing C4-C20carbon atoms, ka is este fraction (B), when this fraction (A) has a lower molecular weight than fraction (B), where the PE the main resin obtained by the polymerization method, in which the catalyst with a single center of polymerization on the metal (SSC) used in the polymerization of at least one of the fractions (a) and (b), and the main resin has
(i) a density less than 940 kg/m3and
(ii) CTP5(the flow rate of the melt) at 190°C/5,00 kg, equal to at least 0.20 g/10 min,
and the polyethylene composition has a time to failure of at least 250 hours, measured according to ISO 1167 at 95°C and 4.3 MPa, and SHI(of 2.7/210)(index reduce the viscosity shear) polyethylene resin base is less than 20.

2. The pipe according to claim 1 where the ethylene copolymer (A) has a density of less than 945 kg/m3.

3. The pipe according to claim 1, where component (A) is the flow rate of the melt P5equal to from 10 to 300/10 minutes

4. The pipe according to claim 1, where in the main polyethylene resin mass ratio between the fraction (a) and fraction (b) is from 60:40 to 40:60.

5. The pipe according to claim 1, where the copolymer of ethylene (a) and Homo - or copolymer of ethylene (B) is subjected to polymerization in the presence of the same catalyst with a single center of polymerization on the metal.

6. The pipe according to claim 1, where the molecular weight distribution (MWD) of the polyethylene resin base is from 5 to 25.

7. The pipe according to claim 1, where SI(5/300)the leaves less than 35.

8. The pipe according to claim 1, where the viscosity of the polyethylene resin base at the shear rate equal to 0.05 kPa (eta0,05), is at least 15000 PA·S.

9. The pipe according to claim 1, where the polyethylene composition has an impact strength by Sharlee at 0°C, equal to at least 8 kJ/m2measured according to ISO 179.

10. The pipe according to claim 1, where the polyethylene composition has a value of RCP-S4 (determination of resistance to rapid crack propagation), is equal to +2°C or less, measured according to ISO 13477.

11. The pipe according to claim 1, where the polyethylene composition has a modulus of elasticity of from 400 to 900 MPa according to ISO 527.

12. The use of a polyethylene composition comprising a polyethylene main resin component to at least 90 wt.% from the overall composition, which contains
A. a copolymer of ethylene with an alpha olefin containing C4-C20carbon atoms, as a fraction (a) and
b. a homopolymer of ethylene or copolymer of ethylene with an alpha olefin containing C4-C20carbon atoms, as a fraction (In),
when this fraction (A) has a lower molecular weight than fraction (B), where the PE the main resin obtained by the polymerization method, in which the catalyst with a single center of polymerization on the metal (SSC) used in the polymerization of at least one of the fractions (a) and (b), and the main resin has
(i) a density below 940 is g/m 3and
(ii) P5at 190°C/5,00 kg, equal to at least 0.20 g/10 min, and the polyethylene composition has a time to failure of at least 250 hours, measured according to ISO 1167 at 95°C and 4.3 MPa, to obtain a pipe, and SHI(of 2.7/210)polyethylene resin base is less than 20.



 

Same patents:

FIELD: chemistry.

SUBSTANCE: composition contains a multimodal polyethylene basic resin obtained during polymerisation of at least one of fractions (A) and (B) in the presence of a single-site catalyst (SSC) on a metal. The fraction (A) in the composition is an ethylene copolymer and fraction (B) is an ethylene homo- or copolymer. Fraction (A) has lower molecular weight than fraction (B). The basic resin has density lower than 940 kg/m3, melt flow rate (MFR2) at 190°C/2.16 kg from 0.001 to 10 g/10 min and the composition has bending modulus between 300 and 820 MPa.

EFFECT: polyethylene composition has good processability during production and flexibility which is sufficient for easy handling, and meets PE63 class requirements or higher for pressure.

13 cl, 1 tbl, 2 ex

FIELD: chemistry.

SUBSTANCE: tube is made from a polyolefin composition which contains a (co)polymer of ethylene or (co)polymer of propylene, a vitamin E type stabiliser of formula (I) , where R1, R2, R3, R4 and R5 independently denote H or unsubstituted or substituted aliphatic or aromatic hydrocarbon radicals which may contain heteroatoms, and a phenol stabiliser of formula (II); in which R6, R7 and R8 independently denote unsubstituted or substituted aliphatic or aromatic hydrocarbon radicals which may contain OH groups; and X1, X2 and X3 independently denote H or an OH group, provided that at least one of X1, X2 and X3 denote an OH group, and optionally an ultraviolet stabiliser.

EFFECT: low emission of additives and products of decomposition thereof in water.

20 cl, 2 tbl, 2 ex

Tube-case // 2418226

FIELD: machine building.

SUBSTANCE: tube-case is of cellular structure consisting of net out of high strength material and solid polymer cover. Also, the net is made out of steel and is connected at intersections, while a polymer cover fills meshes of the net to depth less, than net thickness. The net can be made out of corrosion resistant steel wire, out of wire with corrosion resistant coating, out of spring wire (including the one with corrosion resistant coating) or to be solid metal cut-out-drawn (including zinc-coated). Polymer coating is made out of polymer thermo-plastic material, poly-ethylene of low pressure and thickness of 5-8 mm. It fills meshes to depth less, than net thickness facilitating reliable adhesion of internal surface of the tube-case with a functional material.

EFFECT: increased rigidity of tube-case of cellular structure.

8 cl, 3 dwg

FIELD: machine building.

SUBSTANCE: here is disclosed fabrication of pipe out of composite materials consisting in forming adhesion layer on mandrel, in successive forming sealing, stretching, power and under winding layers by winding composite materials impregnated with polymer binding and in following laying polymer binding on it. The sealing layer is formed by either winding two layers of a band out of non-woven material with pitch of 0.5 of band width impregnated with polymer binding and successive laying one layer of glass cloth on it or by winding two layers of the band out of glass cloth impregnated with glue at pitch of 0.5 of band width. The power layer is formed by the method of cross-layered lengthwise-cross winding out of strands of glass twisted complex thread soaked with polymer binding. The stretching layer is made by spiral-screw winding strands of glass twisted complex thread without impregnation with polymer binding. The under winding layer is formed by spiral screw or cross-layered lengthwise-cross winding strands out of glass twisted complex thread soaked with polymer binding.

EFFECT: increased weight perfection of transport-starting container out of pipe fabricated by winding composite materials; facilitation of pressure tightness and rigidity of pipe.

FIELD: chemistry.

SUBSTANCE: invention relates to use of an antioxidant to increase resistance of a polyolefin composition meant for making pipes to decomposition caused by contact with water, which contains CIO2. The antioxidant is selected from a) a group of phenols of formula I, where R is an unsubstituted or substituted aliphatic or aromatic hydrocarbon radical which can contain heteroatoms, or R is a heteroatom, R' and R" independently denote an unsubstituted or substituted hydrocarbon radical which can contain heteroatoms, or H, X1, X2 and X3 independently denote an unsubstituted or substituted hydrocarbon radical which can contain heteroatoms, or H or OH, where at least X1, X2 or X3 is OH, n assumes values from 1 to 4, and at least one of the phenol substitutes R, R' and/or R" contains at least one sulphur, phosphorus and/or nitrogen heteroatom or from b) amine compounds of formula II, where R1, R2, R3, R4, R5 and R6 independently denote a hydrogen atom or an aliphatic or aromatic hydrocarbon radical, possibly containing heteroatoms, or selected from c) sulphur-containing compounds of formula Ra-S-Rb III, where Ra and Rb independently denote an aliphatic or aromatic hydrocarbon radical, possibly containing heteroatoms.

EFFECT: antioxidant used has low susceptibility to extraction with water carried by a pipe made from such a polyolefin composition.

7 cl, 1 tbl, 2 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a polyethylene composition for making pipes, which contains a polymer base comprising two polyethylene fractions with different molecular weight, to a pipe containing said composition and to use of said composition to make articles, preferably pipes. The polymer base accounts for not less than 90 wt % of the overall composition and has density of 932-938 kg/m3.The fraction of ethylene homo- or copolymer (A) has lower average molecular weight than the fraction of ethylene homo- or copolymer. The polyethylene composition has melt flow rate MFR5 between 0.1 and 0.6 g/10 min and shearing stress η2.7 kPa between 85 and 230 kPa. The polyethylene composition has improved combination of properties, particularly high flexibility, high mechanical strength and good long-term stability.

EFFECT: pipes obtained from the disclosed polyethylene composition have good operational characteristics, long-term stability and good resistance to rapid propagation of cracks, which facilitates their use in conveying liquids under pressure.

16 cl, 1 tbl, 3 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a polyolefin composition which is suitable for making pipes. The composition used to make pipes contains polyolefin (A), a compound (B) which is bis(2,4-dicumyphenyl)pentaerythritol diphosphate, and a phenol compound (C) of formula (I), where R denotes an unsubstituted or substituted aliphatic or aromatic hydrocarbon radical, which can contain heteroatoms, or R denotes a heteroatom; each X1-X5 denotes H, OH and/or R'; where R' denotes a hydrocarbon radical or a hydrogen atom, and n equals 1-4; and g) possibly a stabiliser against UV light (D).

EFFECT: composition has low tendency to migration of additives and their decay products, particularly phenol compounds and a light stabiliser, not more than 1,8 mcg/l with surface to volume ratio S/V between 11,70 and 12,30 dm-1, without loss of stability.

10 cl, 3 tbl, 5 ex

FIELD: chemistry.

SUBSTANCE: polymer base is not less than 90 wt % of the overall composition and has density of 940-947 kg/m3.The fraction of homo- or copolymer of ethylene (A) has lower average molecular weight than the fraction of homo- or copolymer of ethylene. The polyethylene composition has melt flow rate MFR5 of 0.1-0.5 g/10 min and viscosity reduction index during shear (2.7/210) of 10-49, has better combination of properties, in particular high flexibility and high mechanical strength and good long-term stability.

EFFECT: pipes made from the disclosed polyethylene composition have good performance properties, especially in terms of flexibility and rapid propagation of cracks while preserving minimal required strength, processing characteristics, impact viscosity and resistance to slow propagation of cracks.

14 cl, 1 tbl, 3 ex

FIELD: chemistry.

SUBSTANCE: addition of a stabilising amount of a mixture to high density polyethylene, where the said mixture contains 4,4'-bis(α,α-dimethylbenzyl)diphenylamine and sterically hindered phenol, enables to increase resistance to decomposition caused by chlorinated water.

EFFECT: pipes made from such a stabilising composition are suitable for conveying hot water, particularly chlorinated water.

6 cl, 3 ex

FIELD: machine building.

SUBSTANCE: cooling agent pipeline includes the following layers: outer layer from moulding compound on the basis of polyamide; inner layer having the thickness at least of 0.3 mm and containing polypropene, 0.02 wt % of heat stabiliser. Polypropene is hetero-phase copolymer on the basis of propene, which contains 0.5 wt % to 20 wt % of ethene.

EFFECT: increasing heat stability and mechanical pipeline strength.

10 cl, 1 tbl

FIELD: chemistry.

SUBSTANCE: composition contains a multimodal polyethylene basic resin obtained during polymerisation of at least one of fractions (A) and (B) in the presence of a single-site catalyst (SSC) on a metal. The fraction (A) in the composition is an ethylene copolymer and fraction (B) is an ethylene homo- or copolymer. Fraction (A) has lower molecular weight than fraction (B). The basic resin has density lower than 940 kg/m3, melt flow rate (MFR2) at 190°C/2.16 kg from 0.001 to 10 g/10 min and the composition has bending modulus between 300 and 820 MPa.

EFFECT: polyethylene composition has good processability during production and flexibility which is sufficient for easy handling, and meets PE63 class requirements or higher for pressure.

13 cl, 1 tbl, 2 ex

FIELD: metallurgy.

SUBSTANCE: composition consists of copolymer of propylene, of first copolymer of ethylene with at least one linear or branched alpha-olefine having 3-8 carbon atoms and of second copolymer of ethylene with at least one linear or branched alpha-olefine having 3-8 carbon atms. Copolymer of propylene has value of poly-dispersity index within ranges from 4.5 to 10 and contents of isotactic penthalogy above 97.5 mol %. Also, said copolymer contains at least 95 wt % (relative to copolymer) links derivative from propylene. The first copolymer - copolymer of ethylene contains from 25 to less, than 40 wt % relative to this copolymer) links derivative from ethylene and is soluble in xylol at 25°C within the ranges from over 85 to 95 wt %, while the second copolymer of ethylene contains from 50 to less 75 wt %relative to this copolymer) links derivative from ethylene and is soluble in xylol at 25°C within the ranges from over 50 to 85 wt %, and possesses characteristic viscosity of fraction soluble in xylol below 1.8 sh/g.

EFFECT: composition possesses good resistance to stress causing whitening, and lustre combined with good balance of mechanical properties.

8 cl, 3 tbl, 2 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a biodegradable thermoplastic composition used in making films and various hot-moulded articles in form of consumer packaging. The composition contains polyethylene, a copolymer of ethylene and vinylacetate, starch, nonionic surfactant and schungite.

EFFECT: composition has good rheological characteristics and is biodegradable under the effect of light, moisture and soil microflora.

2 tbl, 4 ex

FIELD: chemistry.

SUBSTANCE: invention relates to a polyethylene moulding composition for pressure casting finished parts, for example bottle tops and bottles, and to a method of preparing said moulding composition. The composition has polymodal molecular weight distribution and contains an ethylene homopolymer (A) with low molecular weight, an ethylene copolymer (B) with high molecular weight an ethylene copolymer (C) with ultrahigh molecular weight. At temperature 23°C, the moulding composition has density of 0.948-0.957 g/cm3, melt flow rate MFR (190°C/2.16 kg) of 1-2.7 dg/min and coefficient of viscosity VN3 of the mixture of ethylene homopolymer A, copolymer B and ethylene copolymer C, measured in accordance with ISO/R 1191 in decalin at temperature 135°C ranging from 150 to 240 cm3/g.

EFFECT: besides processability, the moulding composition has high mechanical strength and rigidity, excellent organoleptic properties and high cracking resistance under the effect of the surrounding medium.

12 cl, 2 tbl, 2 ex

FIELD: chemistry.

SUBSTANCE: invention relates to dispersion powdered compositions re-dispersed in water, a method of preparing said compositions, as well as to their use in construction materials. The composition is prepared based on polymers of one or more ethylene unsaturated monomers. The composition additionally contains one or more dimeric surfactants in form of alkyne derivatives, an one or more protective colloids. Powdered compositions are obtained through emulsion or suspension polymerisation of one or more ethylene unsaturated monomers. The reaction takes place in an aqueous medium followed by drying the obtained aqueous dispersions, while adding one or more dimeric surfactants.

EFFECT: use of obtained powdered compositions in self-levelling filler or fluid solutions for making seamless floors, prevents formation of irregularities, depressions and small pores on the surface, as well as formation of air pockets in the deposited layer.

18 cl, 2 tbl, 12 ex

FIELD: chemistry.

SUBSTANCE: mixture contains two different polyolefin and ethylene/α-olefin copolymers. The ethylene/α-olefin copolymer is a block-copolymer containing at least one hard block and at least one soft block. The ethylene/α-olefin copolymer can function as a component which improves compatibility between two polyolefins which may be incompatible. The disclosed polymeric mixtures can be used in making various articles such as tyres, hoses, belts, linings, shoe soles, cast and moulded articles. Said mixtures are especially useful for applications requiring melt strength, such as big articles made by blow moulding, foam and bundled bars.

EFFECT: improved compatibility of mixtures.

27 cl, 10 dwg, 13 tbl, 40 ex

FIELD: chemistry.

SUBSTANCE: composition with multimodal distribution of molecular weight has density between 0.94 and 0.95 g/cm3 at 23°C and melt flow index (MFI190/5) between 1.2-2.1 dg/min in accordance with ISO 1133. The composition contains 45-55 wt % low molecular weight homopolymer A of ethylene, 30-40 wt % high molecular weight copolymer B of ethylene and another olefin containing 4-8 carbon atoms, and 10-20 wt % ultrahigh molecular weight copolymer C of ethylene and another olefin containing 4-8 carbon atoms. The composition has high processibillity and resistance to mechanical loads and breaking, especially at temperatures below 0°C.

EFFECT: flawless coating for steel pips has mechanical strength properties combined with high hardness.

10 cl, 1 tbl, 1 ex

FIELD: chemistry.

SUBSTANCE: invention relates to polymer moulding compositions meant for moulding screw fitments. The composition contains a copolymer of ethylene and 1-hexene with density between 0.947 and 0.962 g/cm3 and melt index between 2 and 8 g/10 min and another copolymer of ethylene and 1-hexene with density between 0.912 and 0.932 g/cm3 and melt index between 0.25 and 6 g/10 min. Difference in density of the two polyethylenes is equal to or greater than 0.03 g/cm3. Selection of the components enables to obtain polymer compositions which have sufficient resistance to cracking and impact strength at low production expenses and without loss of other necessary operational properties.

EFFECT: screw fittings made from the said composition have strength which conforms to requirements for maintaining pressure, particularly in bottles with carbonated drinks, as well as plasticity for providing an airtight seal without need for lining and without change in taste or smell of the contents of the bottle.

9 cl, 4 ex, 6 tbl

FIELD: chemistry.

SUBSTANCE: invention relates to polyethylene and articles made by injection moulding polyethylene. Polyethylene contains homopolymers of ethylene and/or copolymers with ethylene with molecular weight distribution Mw/Mn between 3 and 30, density of 0.945 - 0.965 g/cm3, average molecular weight Mw between 50000 g/mol and 200000 g/mol, high-load melt index (HLMI) between 10 and 300 g/10 min. The polymer contains 0.1-15 branches/1000 carbon atoms, where 1-15 wt % polyethylene with the highest molecular weight has degree of branching greater than 1 branch of side chains with length greater than CH3/1000 carbon atoms.The polyethylene is obtained using a catalyst composition which contains at least two different polymerisation catalysts, where A) is at least one hafnocene-based polymerisation catalyst (A2), and B) is at least one polymerisation catalyst based on an iron component, having a tridentate ligand which contains at least two ortho-, ortho-disubstituted aryl radicals (B). The disclosed polyethylene can be subjected to processing treatment on standard injection moulding apparatus.

EFFECT: articles obtained through injection moulding is uniform and can further be improved by increasing rate of injection moulding or high melting point.

9 cl, 2 tbl, 2 ex

FIELD: chemistry.

SUBSTANCE: invention relates to polyolefin compositions which have high decolouration and impact resistance. The composition contains from 50 to less than 70 wt % crystalline propylene homopolymer, 13-28 wt % elastomeric ethylene and propylene copolymer and 10-22 wt % polyethylene. Total amount of the elastomeric copolymer and polyethylene in the composition is more than 30 wt %. The crystalline propylene homopolymer has polydispersity index ranging from 4 to 10 and amount of isotactic pentades (mmmm) measured using 13C-NMR method on a fraction which is insoluble in xylene at 25°C more than 97.5 mol %. The elastomeric ethylene copolymer is partially soluble in xylene at ambient temperature. The polymer fraction which is soluble in xylene has value of inherent viscosity, measured in tetrahydronaphthalene at 135°C, which ranges from 2 to 4 dl/g. Polyethylene has inherent viscosity ranging from 1 to 3 dl/g.

EFFECT: obtained polypropylene compositions have relatively low hardness, high impact resistance and high resistance to decolouration, which enables their use in the motor car industry, particularly in bumpers and interior finishing, packaging and household objects.

5 cl, 4 tbl, 6 ex

FIELD: chemistry.

SUBSTANCE: composition contains a multimodal polyethylene basic resin obtained during polymerisation of at least one of fractions (A) and (B) in the presence of a single-site catalyst (SSC) on a metal. The fraction (A) in the composition is an ethylene copolymer and fraction (B) is an ethylene homo- or copolymer. Fraction (A) has lower molecular weight than fraction (B). The basic resin has density lower than 940 kg/m3, melt flow rate (MFR2) at 190°C/2.16 kg from 0.001 to 10 g/10 min and the composition has bending modulus between 300 and 820 MPa.

EFFECT: polyethylene composition has good processability during production and flexibility which is sufficient for easy handling, and meets PE63 class requirements or higher for pressure.

13 cl, 1 tbl, 2 ex

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