Polyethylene resin for pipe fitting

FIELD: chemistry.

SUBSTANCE: resin has melt index MI5 from 0.40 to 0.70 g/10 min and contains from 47 to 52 wt % low-molecular polyethylene fraction and from 48 to 53 wt % high-molecular polyethylene fraction, where the high-molecular polyethylene fraction includes a copolymer of ethylene and 1-hexene and 1-octene.

EFFECT: improved hydrostatic properties.

5 cl, 3 tbl, 6 ex

 

The present invention relates to polyethylene resins, more specifically to those that are acceptable for use as pipe connection fittings for pipes or fittings, and to a method for producing such resins. The object of the present invention is also the use of polyethylene compositions comprising such resins for the manufacture of pipes or valves and such fittings.

Polyolefins, such as polyethylene, which have high molecular weight, usually characterized by improved mechanical properties in comparison with their more low molecular weight analogues. However, when the processing of high molecular weight polyolefins can create problems of a technological nature and can be costly to obtain.

For many purposes the use of HDPE is essential polyethylene with improved rigidity, strength and resistance to cracking under stress environment (SRNA). These improved properties are more easily achievable with the use of high molecular weight polyethylene. However, as the molecular weight of the polymer increases, the processability of the resin decreases. The target properties, which are characteristic of high molecular weight resins stored at simultaneously improved processing AIDS, in which W is therefore extraterrest, provided you create a polymer with a broad or bimodal molecular mass distribution (MMD).

Plastic resin known as used for the manufacture of pipes and fittings. The resins for the manufacture of pipes required high stiffness (resistance to fracture under sustained load) in combination with high resistance against slow growth of cracks, and resistance to crack propagation, causing impact strength. However, there is a need for increased resistance to fracture with long-term loads currently available resins for the manufacture of pipes while maintaining at least the same level of resistance against slow growth of cracks and rapid propagation of cracks. This would increase such pipe nominal pressure value.

Polyethylene pipes are used widely because they are lightweight and can be easily assembled by fusion welding. Polyethylene pipes also have good flexibility and impact resistance and is not subject to corrosion. However, if plastic pipes are not enforced, they are limited hydrostatic resistance due to the inherent polyethylene of low yield strength. It is generally accepted that the higher the density of the polyethylene, the higher the long-term hydrostatic stoikos the ü. In this area known in the art resins for the manufacture of pipes that exist under the designations "PE 80 and PE 100". This classification is described in ISO 9080 and ISO 12162. They represent a polyethylene resin, which, when used for the manufacture of pipes of a certain size, at different temperatures stand the test of long-term pressure, over a period of 5000 hours Extrapolation in accordance with ISO 9080 shows that they extrapolate at 20°C/50 years of the voltage at the lower projected level (confidence level of 97.5% - "NPI") of at least 8 and 10 MPa; such resins are known as resin, respectively, PE 80 and PE 100. The density of modern primary powder used in the preparation of composition D 100, close to 0,950 g/cm3(usually from 0,949 to 0,951 g/cm3). Such a polyethylene resin containing the normal amount of black pigments, have densities from about 0,958 to 0,960 g/cm3. It is necessary that such properties possessed valves. In addition, it is necessary that valve had good resistance to deflection.

In the art it is known that the key components for a good resin D 100 are a combination of low molecular weight high density polyethylene with a small amount of or without short-chain time is evlenia (CCR) thanks to the introduction of comonomeric links and linear polyethylene resin of low density (LLDPE) with a high molecular weight and CCR.

Typically a polyethylene resin such composition produced by the process in a cascade reactor with the use of catalysts of the Ziegler-Natta. Another option may be a mixture of different polyethylene powders and their extrusion with obtaining physical mixture, in contrast to chemical mixtures prepared with the use of a cascade reactor. However, the physical mixing often results in poor mixing of the melts, which remain large macromolecular microscopic particles (referred to in the art gels), included in the final product. Mass fraction of LLDPE resin is about 50% of the mixture. Low molecular weight high density polyethylene (HDPE) gives a mixture of high crystallinity and, thus, high rigidity and creep resistance and lowers the melt viscosity of the mixture. High molecular weight LLDPE provides education polyethylene compound with high density associated molecules by short-chain branching, which causes a high resistance to cracking under stress environment (SRNA), celebrated in these mixtures.

In WO 00/60001 described having a high density multimodal polyethylene for use in pipes with characteristic PE 80 and PE 100, in which high molecular weight is Olya, usually ranges from 45 to 55 wt.% composition, and having a density less than 0.930 g/cm3and IRBN (melt index under a heavy load) less of 0.30 g/10 min IL5resin generally ranges from 0.2 to 0.3 g/10 minutes

In WO 02/34829 described having a high density multimodal polyethylene for use in pipes or fittings, in which the resin typically has IR5from 0.2 to 0.6 g/10 min, and the low molecular weight fraction (block NMC, low molecular weight components) is at least 51 wt.% the resin. In example 1, in particular, the block NMC is 55 wt.% resin and the resin has IR50,63 g/10 min. the resin unacceptable for valves due to the very narrow molecular mass distribution (MMD) of the individual blocks, and the narrow MMD prepared compositions inevitably leads to poor homogeneity and poor processability.

In WO 02/102891 described having a high density multimodal polyethylene for use in pipes or fittings, in which the resin typically has IR5from 0.15 to 2 g/10 min, and the low molecular weight fraction is at least 53 wt.% the resin. In example 10, in particular, the block NMC accounts for 58.4 wt.% resin and the resin has IR50,54 g/10 min. the resin unacceptable for valves due to the fact that a very large proportion of the first b is an eye inevitably leads to poor homogeneity of the product, explaining poor mechanical properties.

In JP 2000-109521 And described with a high density multimodal polyethylene for use in pipes or fittings, in which the resin typically has IR5from 0.25 to 0.50 g/10 min, and the low molecular weight fraction ranges from 45 to 60 wt.% the resin. Any specific guidance on the application of 1-hexene or 1-octene as co monomer in the high molecular weight fraction is missing. In the examples of carrying out the invention refers to only IL50,42 g/10 min, but at the same time as co monomer using 1-butene, and, consequently, the product has a density of 952 kg/m3.

When creating the present invention, it was found that by selecting a particular combination of properties it is possible to obtain resins with hydrostatic properties required for pipes that make them particularly well-suited for the manufacture of pipe fittings and pipes.

Accordingly, the first object of the present invention is a polyethylene resin having IL5from 0.40 to 0.70 g/10 min and containing from 47 to 52 wt.% low molecular weight polyethylene fraction and from 48 to 53 wt.% high molecular weight polyethylene fraction, where high molecular weight polyethylene fraction comprises a copolymer of ethylene or 1-hexene or 1-octene.

When creating the infusion is his invention was installed, that the above choice of molecular weight, density and m5can lead to a noticeable improvement of the characteristics of processing AIDS in casting fittings under pressure, in comparison with other RE 100 equivalent varieties, while maintaining or even improving the mechanical properties, such as resistance to cracking due to tension. Thus, in particular, molded by injection molding pipe fittings are manufactured using the resin according to the invention demonstrate excellent resistance to relaxation after molding. In the case of a resin containing as comonomeric parts of 1-butene, this balance of properties is not possible.

Preferred low molecular weight polyethylene fraction comprises polyethylene having a density of at least 0,965 g/cm3and m2from 5 to 1000 g/10 min, and high molecular weight polyethylene fraction has a density of from 0.910 to 0,940 g/cm3and m5from 0.01 to 2 g/10 minutes

In addition, an object of the present invention is the use of such a polyethylene resin for the manufacture of pipes and fittings, and another object is to pipe or fitting comprising a polyethylene resin according to the invention.

Preferred high molecular weight fraction comprises from 0.1 to 10 wt.% comonomeric links (i.e. 1-hexenoic or 1-octene is o).

Preferred IL5resin ranges from 0.45 to 0.65 g/10 min, This value refers to the resin after granulation, and not immediately at the outlet of the polymerization reactor. Considering the purpose of the present invention, IR2and m5present yield installed in accordance with ASTM D 1238 (1986) at a temperature of 190°C. under a load, respectively 2.16 and 5 kg. flow Index of IRBN or IL21mean flow index, determined in accordance with ASTM D 1238 (1986) at a temperature of 190°C. under a load of 21.6 kg

In a preferred embodiment, the resin of the present invention comprises from 48 to 51 wt.% low molecular weight fraction, more preferably in the range from 49 to 51 wt.%.

In a preferred embodiment, the resin in accordance with the invention have a density after granulation (not immediately at the outlet of the polymerization reactor), determined in accordance with ASTM D 792 (on the sample obtained in accordance with the method of ASTM D 1928) at least 957 kg/m3more specifically, at least 959 kg/m3. In a preferred embodiment, the density does not exceed 963 kg/m3. Especially preferred are resin, the density of which is in the range from 959 to 961 kg/m3. These density values correspond to Zn is the density values of natural resins, i.e. resin at the exit from the reactor before the introduction of any additives such as pigments, at least 948 kg/m3more specifically, at least 950 kg/m3preferably not more than 954 kg/m3and specifically in the range from 950 to 952 kg/m3.

In a preferred embodiment, the density of the polymer (A)contained in the resin in accordance with the invention, is at least 972 kg/m3. In a preferred embodiment, the density of the copolymer (B) is at least 910 kg/m3. In a preferred embodiment, the density of the copolymer (B) does not exceed 928 kg/m3more specifically does not exceed 926 kg/m3.

Considering the purpose of the present invention, the ethylene polymer (A) is an ethylene polymer comprising monomer units, derivateservlet from ethylene, and possibly monomer units, derivateservlet of other olefins. The copolymer (B) is a copolymer comprising monomer units, derivateservlet from ethylene and monomer units, derivateservlet of 1-hexene or 1-octene.

Considering the purpose of the present invention, the content hexenoic or oktanovyh links define13C-NMR analysis in accordance with the method described in J.C.RANDALL, JMS REV.MACROMOL.CHEM. PHYS., S(2&3), s-317 (1989). For example, the content of the links, derivatize the bathrooms of the co monomer, relying on the results of the definitions of integrals of the characteristic spectral lines of co monomer (for example, hexene: 23,4; and 34,9 38,1 frequent./million) relative to the integral of the characteristic spectral lines of links, derivatizing from ethylene (30 ppm million).

Content in the copolymer (B) Monomeric units, derivatizing of 1-hexene or 1-octene, hereafter referred to as content comonomeric links, usually at least 0.4 mol %, in particular at least 0.6 mol %. Content comonomeric units in the copolymer (B) is usually at most of 1.8 mol %, preferably at most a 1.5 mol %. Particularly preferably, the content comonomeric links, which is in the range of 0.7 to 1.1 mol %.

The ethylene polymer (A) may, optionally, contain monomer units, derivateservlet from another olefin. In a preferred embodiment, the ethylene polymer (A) includes at least of 99.5 mol %, more specifically at least 99,8 mole % of monomer units, derivatizing from ethylene. Particularly preferred ethylene Homo-polymer.

In a preferred embodiment, the polymer (A) in accordance with the invention has IR2at least 200, preferably at least 250 g/10 min IL2polymer (A) is usually not more than 1000 g/10 min, suppose that the equipment does not exceed 700 g/10 min The polymer (A) in the preferred embodiment, has IRBN at least 1000 g/10 minutes

In a preferred embodiment, the polymer (A) has a characteristic viscosity ηA (defined in tetrahydronaphtalene at 160°C and a concentration of 1 g/l using a viscometer of the type of Ostwald viscometer (K2/K1: approximately 620)at least equal to 0.45 DL/g, preferably at least of 0.50 DL/g, Its characteristic viscosity usually does not exceed 0,75 DL/g, and in the preferred embodiment, is not higher than 0.65 DL/g

In a preferred embodiment, the melt index IL5copolymer (B) in accordance with the invention is at least 0.005 g/10 min In a preferred embodiment, it is not more than 0.1 g/10 min, the Copolymer (B) in appropriate variant has IRBN at least 0.05 g/10 min, which also does not exceed 2 g/10 minutes

The copolymer (B) in General has a characteristic viscosity η at least to 2.7 DL/g, preferably at least a 3.9 DL/g Its characteristic viscosity η usually does not exceed 10,9 DL/g, preferably not greater than about 7.6 DL/g

The resins in accordance with the invention the ratio between the characteristic viscosity of the copolymer (B) (η) and a characteristic viscosity of the polymer (A) (η) is typically at least 4, preferably at least 6. The ratio η/η usually will not exceed Iset 15, preferably does not exceed 12.

Resin in accordance with the invention typically has a ratio of IRBN/IL5more than 20, preferably greater than 25. The ratio of IRBN/IL5usually does not exceed 150. In a preferred embodiment, the ratio of IRBN/IL5does not exceed 70. The ratio of IRBN/IL5resin illustrates a broad or bimodal molecular weight distribution of resin.

Each of the polymer (a) and copolymer (B)used in the resin in accordance with the invention, has a molecular weight distribution, characterized by the value of MW/Mnmore than 4. The ratio of MW/Mnmeans the ratio between srednevekovoi molecular mass MWand srednekamennogo molecular mass Mnpolymer as specified exclusion (molecular sieve) chromatography (has been) in accordance with developed standards ISO/DIS 16014-1 and ISO/DIS 16014-2. Has been carried out in 1,2,4-trichlorobenzene at 135°C and 1 ml/min in the chromatograph Waters 150°C, equipped with a refractometric detector. The injection is performed with the application of a series of four Waters columns®HT-6E in the following conditions: injection of 400 μl of the polymer solution of 0.5 g/l and product IRGANOX®1010, a linear calibration curve based on the coefficients of Brand-Houwink to polister the catch K=1,21×10 -4and a=0,707 and polyethylene To=to 3.92×10-4and a=0,725.

In a preferred embodiment, the polymer (A) has the value of the molecular mass distribution of MW/Mnnot more than 12, more specifically not more than 10. In a preferred embodiment, the copolymer (B) has the value of the molecular mass distribution of MW/Mnat least 6 but not more than 15, preferably not more than 12. It was found that the use of polymers (a) and (B)with the value of the molecular mass distribution of MW/Mnmore than 4, makes it possible to prepare compositions having improved homogeneity, when this composition is used, in comparison with compositions having the same composition and similar characteristics, but includes ethylene polymers having a value of the molecular mass distribution of MW/Mnless than 4.

In a preferred embodiment, the resin according to the invention are obtained from the application of the method in which use at least two connected in series polymerization reactor, in accordance with which:

in the first reactor, the ethylene will polimerizuet in suspension in a medium comprising a diluent, hydrogen, a catalyst based on a transition metal and socialization and thereby gain from 47 to 52 m is S.% based on the total weight of the composition of the ethylene polymer (A)

in addition, the medium comprising polymer (A), take away from the above-mentioned reactor and is subjected to expansion so that degassing, removing at least part of the hydrogen, then

mentioned at least partially degassed medium comprising polymer (A) and some ethylene and 1-hexene or 1-octene and optionally at least another alpha-olefin containing from 4 to 10 carbon atoms, is introduced into the subsequent reactor in which the polymerization in suspension to get from 48 to 53 wt.% in terms of the total weight of the composition of the ethylene copolymer (B).

Polymerization in suspension means a polymerization diluent, which created the polymerization conditions (temperature, pressure) is in a liquid state, and these polymerization conditions or diluent such that at least 50 wt.% (preferably at least 70%) of the resulting polymer is not soluble in the above-mentioned diluent.

The diluent used in the polymerization process, is usually a hydrocarbon diluent, inert in relation to the catalyst, socializaton and the resulting polymer, such as linear or branched alkane or cycloalkane containing from 3 to 8 carbon atoms, in particular hexane or Sobota is.

The amount of hydrogen introduced into the first reactor, usually set in such a way as to achieve the diluent values of molar ratio between hydrogen and ethylene from 0.05 to 0.1. In a preferred embodiment, in the first reactor, the value of this molar ratio is at least 0,1.

Wednesday, withdrawn from the first reactor, comprising, in addition, the polymer (A), subject to extension to remove (degassing) at least part of hydrogen. In a useful embodiment, this extension is carried out at a temperature below or equal to the temperature of polymerization in the first reactor. The temperature at which expansion is usually above 20°C, preferably at least 40°C. the Pressure at which the extension below the pressure in the first reactor. In a preferred embodiment, the pressure of expansion of less than 1.5 MPa. Pressure expansion is usually at least 0.1 MPa. The amount of hydrogen still being in at least partially degassed environment, typically less than 1 wt.% from the amount of hydrogen initially present in the medium discharged from the first polymerization reactor, and in the preferred embodiment, this amount is less than 0.5%. The amount of hydrogen in partially degassed environment introduced in section the following polymerization reactor, it appears, therefore, small or even zero. In a preferred embodiment, in the subsequent reactor also serves hydrogen. The amount of hydrogen introduced into the subsequent reactor, usually set in such a way as to achieve the diluent values of molar ratio between hydrogen and ethylene from 0.001 to 0.1. In a preferred embodiment, in the subsequent reactor is such a molar ratio is at least 0,004. In the preferred embodiment, it is not greater than 0.05. In the method in accordance with the invention the ratio between the hydrogen concentration in the diluent in the first reactor and the hydrogen concentration in the diluent in the subsequent polymerization reactor is generally at least 20, preferably at least 30. Particularly preferably, the ratio of concentrations equal to at least 40. The value of this ratio is typically less than 300, preferably not more than 200.

The number of 1-hexene or 1-octene, introduced in the subsequent polymerization reactor, such that in the preferred embodiment, in the subsequent reactor is the molar ratio of co monomer/ethylene in the diluent is at least to 0.05, more preferably at least 0,1. Preferred is a molar ratio of co monomer/ethylene offset is et 3, more preferably does not exceed 2,8.

The catalyst used in the polymerization process, may be any catalyst (catalysts)that are acceptable for obtaining fractions of low and high densities. In a preferred embodiment, the catalyst provides education as high-and low-molecular-weight fractions. For example, the catalyst can serve as a chromium catalyst, a catalyst of the Ziegler-Natta or metallocene catalyst. In a preferred embodiment, the catalyst is a catalyst of Ziegler-Natta.

In the case of a catalyst of Ziegler-Natta this used catalyst includes at least one transition metal. Under transition metal mean metal of group 4, 5 or 6 of the Periodic table of the elements (CRC Handbook of Chemistry and Physics, 75th edition, 1994-95). In a preferred embodiment, the transition metal is titanium and/or zirconium. In the preferred embodiment, uses a catalyst that includes not only the transition metal, but also magnesium. Good results are achieved with catalysts, including:

from 10 to 30%, preferably from 15 to 20%, more preferably from 16 to 18 wt.%, transition metal,

from 0.5 to 20%, preferably from 1 to 10%, more preferably from 4 to 5 wt.%, magnesium

from 20 to 60%, preferably from 30 to 50%, more preferably from 40 to me.%, of a halogen atom, such as chlorine,

from 0.1 to 10%, preferably from 0.5 to 5%, more preferably from 2 to 3 wt.%, aluminium;

and the rest usually falls on the items that are due to the products used for their preparation, such as carbon, hydrogen and oxygen. In the preferred embodiment, these catalysts are prepared by coprecipitation of the composition of at least one transition metal and magnesium composition using halogenated alumoorganic composition. Such catalysts are known, they generally described in US 3901863, US 42942200 and US 4617360. In a preferred embodiment, such a catalyst is injected only into the first polymerization reactor, i.e. the introduction of fresh catalyst in the subsequent polymerization reactor does not operate.

In the preferred embodiment, used in the process of socialization is alumoorganic connection. Preferred legalaidboard.ie alumoorganic the compounds of formula lR3in which R denotes an alkyl group containing from 1 to 8 carbon atoms. Especially preferred are triethylaluminum and triisobutylaluminum. Acetalization is introduced into the first polymerization reactor. Fresh socialization can also be introduced into the subsequent reactor. The number of socializaton introduced into the first reactor, obychnoystali at least 0,1×10 -3mol/l of diluent. Usually it does not exceed 5×10-3mol/l of diluent. Any number of fresh socializaton introduced into the subsequent reactor, typically less than 5×10-3mol/l of diluent.

In a preferred process according to the invention using the catalyst of the Ziegler-Natta the polymerization temperature is usually from 20 to 130°C. In a preferred embodiment, it is equal to at least 60°C. In a more preferred embodiment, it does not exceed 115°C. the Total pressure at which carry out the process, is usually from 0.1 to 10 MPa. In a preferred embodiment, in the first polymerization reactor total pressure is at least 2.5 MPa. In the preferred embodiment, it does not exceed 5 MPa. In a preferred embodiment, in the subsequent polymerization reactor total pressure is at least 1.3 MPa. In the preferred embodiment, it does not exceed the 4.3 MPa.

The duration of polymerization in the first reactor and then the reactor is generally at least 20 minutes, preferably at least 30 minutes Usually it does not exceed 5 hours, preferably does not exceed 3 hours

In this process, the suspension comprising the resin according to the invention, is collected at the outlet of the subsequent polymerization reactor. The composition can be separated from the suspension using lubog the known means. Typically, the suspension is affected by the pressure expansion (final extension) thus, to remove from the composition of the diluent, ethylene, alpha-olefin and all hydrogen.

The implementation of such a method makes it possible to obtain in good yield and with low content of oligomers of the composition, is characterized by a very good compromise between mechanical properties and suitability for practical application.

The composition of the invention are well suited for the manufacture of pipes and pipe fittings, in particular pipes for conveying pressure fluid, such as water and gas. Therefore, the scope of the invention also covers the use of a composition in accordance with the invention for the manufacture of pipes or pipe fittings. Naturally, when they are used for moulding articles in the molten state, and more specifically for the manufacture of pipes or pipe fittings, the composition of the invention can be mixed with the usual additives for practical application of polyolefins, such as stabilizers, antioxidants, acid binding agents and/or absorbers of UV rays), antistatic agents, auxiliary agents ("substance to improve the technological properties") and pigments. Therefore, the scope of the invention also includes a mixture containing compositions is the Oia in accordance with the invention and at least one of the above additives. Particularly preferred mixture comprising at least 95%, preferably at least 97 wt.%, compositions in accordance with the invention and at least one of the above additives. The manufacture of pipes by extrusion of a composition in accordance with the invention in the preferred embodiment, is performed on the extrusion line includes extruder, calibration and pulling device. Extrusion is usually carried out in a single screw extruder of the type and at a temperature of from 150 to 230°C. Calibration of pipes can be done by creating an outside pipe negative pressure and/or creation inside the tube positive pressure.

Pipes manufactured using the compositions in accordance with the invention, are characterized by the following:

good resistance to the slow growth of cracks (MFFT), reflected by the time of destruction, as determined by the method described in the standard preparation ISO/DIS 16770.2 (2001) (at 80°C under a load of 5.0 MPa (in 2%solution of Arkopal N100)), exceeding 100 h;

good resistance to rapid crack propagation (BRT), reflected stop the propagation of cracks when the internal pressure equal to at least 10 bar, as determined at 0°C on pipe with a diameter of 110 mm and thickness of 10 mm in accordance with the method of S4, described in ISO F/DIS 13477 (1996);

good long-term resistance to pressure, which may allow them to assign a higher score MRS than MRS 10 in accordance with ISO/TR 9080.

To illustrate the invention the following examples.

EXAMPLES 1 to 6

a) Preparation of catalyst

Deatiled magnesium was injected into the reaction for 4 h at 150°C with tetrabutyltin titanium in such quantities, at which the value of the molar ratio of titanium to magnesium was equal to 2. To prepare a solution containing 250 g of a mixture of/l solution in alcoholate mixture of hexane was added for polymerization. After this, the thus obtained product of the interaction were chlorinated and besieged its introduction in contact for 90 min at 45°C with a solution of atrological. Thus prepared catalyst was extracted from the suspension consisted of (in wt.%):

Ti: 17; Cl: 41; Al: 2; Mg: 5.

b) Polymerization

In suspension in the isobutane in two serially connected reactors, circulation, separated by a device that creates an opportunity for maintaining a constant pressure expansion, preparing the ethylene polymer composition.

In the first reactor with circulation continuously introduced catalyst, which is described in PA) of example 1, and in this environment was carried out by polymerization of ethylene with obtaining the polymer (who). Of the above-mentioned reactor continuously averted the environment, including, in addition, the polymer (A), and subjected to the expansion (48°C 0.6 MPa) so as to remove at least part of hydrogen. Then the resulting environment, at least partially degassed to remove hydrogen was continuously introduced into the second polymerization reactor simultaneously with ethylene, hexene, isobutene and hydrogen, and carried out the polymerization of ethylene and hexene with obtaining the copolymer (B). From the second reactor was continuously removed the suspension, comprising the polymer composition, and this suspension was subjected to a final extension to evaporate contained isobutane and chemicals (ethylene, hexene, and hydrogen) and to select the composition in the form of a powder, which was subjected to drying in order to complete the degassing to remove isobutane.

Other polymerization conditions shown in table 1.

Preparation of a mixture of

The resins of examples 1 through 6 100 frequent. polyethylene composition was added to 0.35 wt. frequent. antioxidant IRGANOX®B225, of 0.075 wt. frequent. stearate zirconium, of 0.025 wt. frequent. calcium stearate and 2.25 wt. frequent. carbon soot.

The prepared composition was extrudible in the device for preparing a mixture including a melting zone (single-screw extruder with screw diameter of 90 mm and a length of 24 diameter is) and the area of homogenization (single-screw extruder with screw diameter of 90 mm and a length of 36 diameters) in the performance of 40 kg/h and with a length of stay 540 C. At the end of the device for mixing the resulting mixture was passed through beam granulator and allocated granules prepared mixture.

td align="center"> 1,28
TABLE 1
EXAMPLE123456
The REACTOR 1
With2(g/kg of diluent)18,819,821,120,320,320,5
The molar ratio of N2/S263,843,8to 43.147,448,446,2
T (°C)858585858585
The residence time of material in the machine (h)1,33 1,31,321,321,321,32
REACTOR 2
With2(g/kg of diluent)14,913,8to 12.014,915,114,3
The molar ratio of N2/S20,730,510,470,710,690,56
The molar ratio of C6/S2187177183,2143128,1147
T (°C)757575757575
The residence time of material in the machine (h)1,291,281,31,321,29

0,68
TABLE 2
EXAMPLE123456
The reactor 1
P1 (wt.%)48,953,152,749,049,049,0
IL2(g/10 min)#27,47,510,88,98,39,3
Density (kg/m3)973,7972974971,5971,2971
The final granulated product
IL5(g/10 min)0,570,580,450,570,44
IL21(g/10 min)13,111,711,812,810,39,9
µ2(1000 PA·s)2020,8of 21.221of 21.922,7
Mw/Mnrate 18.8915,9818,317,8415,5619,61
Density (kg/m3)*958,9959,9958959,9960,2958,1
# IL2defined by head 8 mm length/inner diameter of 1.0 mm, which gives a value of approximately 19 smaller than the head 8 mm/2,095 mm *including pigment

Tests on the mechanical properties

Creep resistance

Resistance, good discharge performance is e creep was determined in 50 mm pipes SDR 17, manufactured using extrusion KM and/or Battenfeld in accordance with ISO 1167. The results of the pressure test has been based on an assessment of MRS equal to 10 MPa in accordance with ISO 9080.

Resistance to cracking due to stress

Resistance to cracking due to stress was determined by tests on pipes SDR 11 with a cut diameter of 110 mm in accordance with ISO 13479.

Rapid crack propagation

Rapid crack propagation was established under internal pressure equal to at least 10 bar, and the determination was carried out at 0°C on pipe with a diameter of 110 mm and thickness of 10 mm in accordance with the method of S4, described in ISO 13477.

TABLE 3
EXAMPLE123456
Creep resistance
Pipe 1 and 12.4 MPa142190 138142337209
Pipe 2 - 12,4 MPa152200121184418198
The pipe 1 is 12.1 MPa9377315388791149465
The pipe 2 is 12.1 MPa10188155839891160459
Pipe 1 - 5.5 MPa1672302088973898449
Pipe 2 - 5.5 MPa14027727710704129555
Pipe 1 - 5.0 MPa65214820-46634201
Resistance to cracking due to stress - test the pipe with cut
Pipe 1 - 4,6 MPa349824027956153715634100
Pipe 2 - 4,6 MPa347025268712141416024663
Rapid crack propagation
EXAMPLE123456
0°C>10>10 >10>10>10
-5°C>8>10>10>10>10
-10°C>10>104>10>10
-15°C3,503,503,50>5

From the above table we can see that all resins comply with European standards (EN 1555 - EN 12201 - ISO 4427 - ISO 4437) on the creep resistance applied to the resin D 100:

at least 100 hours at 12,4 MPa, 20°C;

at least 165 h at 5.5 MPa, 80°C without brittle fracture;

at least 1000 h at 5 MPa, 80°C.

With regard to resistance to cracking is the result of voltage, all resins are guaranteed to comply with European standards (EN 1555 - EN 12201 - ISO 4427 - ISO 4437)for resin D 100, which consist in time resistance at least equal to 165 h at 80°C, 5.5 MPa.

All resins exhibit good resistance to rapid crack propagation (BRT).

1. Polyethylene resin having a melt index IL5from 0.40 to 0.70 g/10 min and containing from 47 to 52 wt.% low molecular weight polyethylene fraction and from 48 to 53 wt.% high molecular weight polyethylene fraction, and high molecular weight polyethylene fraction comprises a copolymer of ethylene or 1-hexene or 1-octene.

2. Resin according to claim 1, in which the low molecular weight polyethylene fraction comprises polyethylene having a density of at least 0,965 g/cm3and melt index IL2from 5 to 1000 g/10 min, and high molecular weight polyethylene fraction has a density of from 0.910 to 0,940 g/cm3and melt index IL5from 0.01 to 2 g/10 minutes

3. Resin according to claim 1, which comprises from 48 to 51 wt.% in terms of the total weight of the composition of low molecular weight polyethylene fraction.

4. Resin according to claim 3, which comprises from 49 to 51 wt.% in terms of the total weight of the composition of low molecular weight polyethylene fraction.

5. Resin according to any one of claims 1 to 4, after which the granulation and the additive has a density in the range from 957 to 963 kg/m 3.



 

Same patents:

FIELD: chemistry.

SUBSTANCE: invention relates to polyethylene mixed compositions, intended for film manufacturing, which include two or more different ethylene polymers, each of which has different degree of complexity of long chain branching. Polyethylene composition is practically linear and has average index of branching constituting 0.85 or less. In addition, composition has density 0.935 g/cm3 or less, dullness - 10% or less and stability to falling load impact - 100g/mm or more, determined according to ASTM D-1709 methodology.

EFFECT: polyethylene compositions possess definite combination of required properties and characteristics, good optic properties and strengthening characteristics.

15 cl, 1 dwg, 5 tbl, 5 ex

FIELD: chemistry.

SUBSTANCE: invention refers to making a moulded product for handling clean-room materials, intermediate products or end products, such as a container, a tray and a tool. The moulded product is made of resin compound prepared by mixing in melt cycloolefine polymer (A) 100 weight fractions chosen from the group including bicyclo[2.2.1]-2-heptene and its derivatives, tricyclo [4,3,0,12,5]-3-decene and its derivatives, and tetracyclo[4,4,0,12,5,17,10]-3-dodecene and its derivatives of vitrification temperature within 60 to 200°C, and amorphous or low-crystalline elastic copolymer (B(b1)) 1 to 150 weight fractions. Copolymer (B(b1)) is polymerised from at least two monomers chosen from the group including ethylene and a-olefin with 3 to 20 carbon atoms and vitrification temperature 0°C or lower. The compound contains radical polymerisation initiator 0.001 to 1 weight fractions containing peroxide, and polyfunctional compound (D) 0 to 1 weight fractions. The compound (D) has at least two radical-polymerised functional groups chosen from the group including vinyl group, allylic group, acrylic group and methacrylic group in a molecule.

EFFECT: clean-room moulded product is characterised with good chemical stability, heat resistance and dimensional accuracy, it prevents volatile component release in the surrounding space, has good abrasion resistance and prevents particle formation.

19 cl, 1 tbl, 2 dwg, 12 ex

Polyethylene films // 2349611

FIELD: packing industry.

SUBSTANCE: invention relates to polyethylene films and first of all to bimodal polyethylene compositions designed for the production of films with low impurities content and increased manufacturability. The film contains polyethylene composition with the density of 0.940-0.970 g/cm3 and melt index value (I21) measured according to ASTM-D-1238-F technique 190°C/21.6 kg, from 4 to 20 dg/min. The polyethylene composition contains a high-molecular component with the average molecular weight more than 50000 and a low-molecular component with the average molecular weight less than 50000.

EFFECT: definite combination of the composition polymer characteristics meets the commercial requirements to the production of polyethylene films suitable for manufacturing the films by moulding, blow formation and other methods, the films are characterised by improved operational parameters along with high film quality that is revealed by low gel fraction content and simultaneous retention of strength, flexibility and impact resistance values.

28 cl, 7 dwg, 6 tbl, 12 ex

FIELD: chemistry.

SUBSTANCE: invented here is a copolymer of ethylene with α-olefins, with molecular weight distribution Mw/Mn from 1 to 8, density from 0.85 to 0.94 g/cm3 , molecular weight Mn from 10000 g/mol to 4000000 g/mol, not less than 50% distribution width index of the composition, and at least, bimodal distribution of branching of side chains. Branching of side chains in maximums of separate peaks of distribution of branching of side chains in all cases is larger than 5 CH3/1000 carbon atoms. Ethylene copolymers are obtained in the presence of a catalyst system, comprising at least, one monocyclopentadienyl complex A) or A'), optionally an organic or inorganic substrate B), one ore more activating compounds C) and optionally one or more compounds, containing group 1, 2 or 13 metals of the periodic system D).

EFFECT: invented compounds have bimodal distribution of short-chain branching and narrow molecular weight distribution, as well as high impact property.

11 cl, 1 tbl, 3 ex, 2 dwg

FIELD: chemistry.

SUBSTANCE: present invention pertains to a method of obtaining a resin composition. Description is given of the method of obtaining a resin composition through mixture in a molten mass of 100 weight parts of cyclic olefin polymer (A), whose glass transition temperature ranges from 60 and 200°C, and 1-150 weight parts of elastic polymer (B), with glass transition temperature 0°C or lower. Part of the cyclic olefin polymer (A) is first mixed in a molten mass with elastic polymer (B) and 0.001-1 weight parts of radical polymerisation initiator (C). The remaining cyclic olefin polymer (A) is then added and mixed in the molten mass. The ratio of the quantity of cyclic olefin polymer (A), initially added, to the quantity of the same polymer added later (initially added/added later) ranges from 1:99 to 70:30. Cyclic olefin polymer (A) is divided into two parts and added separately twice, such that, the mixture with a cross-linked structure can be diluted with cyclic olefin polymer (A), without a cross-linked structure. As a result, increase in the viscosity of the molten resin composition can be prevented.

EFFECT: good abrasion resistance and good moulding properties of the molten mass.

15 cl, 1 tbl, 4 ex

FIELD: chemistry.

SUBSTANCE: film is made from polymer mixture, which contains (wt %): 50-90% composition of the ethylene polymer and 10-50% polymer component on ethylene basis, having a density in the range from 0.9 to 0.930 g/ml and molten flow-rate till 4 g/10 min. Composition of the ethylene polymer contains a recurring unit, obtained from an ester, selected from (1) ethylene-unsaturated organic monomer in the form of esters unsaturated C3-C20 monobasic carboxylic acids and C1-C24 univalent aliphatic or alicyclic alcohols, (2) vinyl esters saturated C2-C18 carboxylic acids, where the content of esters is in the range from 2.5-8 wt %. Composition of the ethylene polymer has a density in the range from 0.920 to 0.94 g/ml. Stretchable packing film has a relation between the value of tear resistance longitudinally and the vale of tear resistance transversely, which exceeds 0.3 and the value of ultimate tensile strength lengthwise 30% in the range from 6.5 to 15 N.

EFFECT: effective application in the capacity of stretching adhesive covers in various operations in linking packing and wrapping.

6 cl, 3 tbl, 17 ex

FIELD: chemistry.

SUBSTANCE: polymer composition contains low- and high-molecular polyethylene components, the composition basically having a single peak of lamella width percentile curve and PENT greater than 1000 hours at 80°C and 2.4 MPa according to ASTM F1473. The process has several variants allowing production of tubes with enough viscosity to resist shock during laying or afterward; and with extra long working life under gas or water pressure, especially resistant to environmental stress cracking and to creep under internal pressure.

EFFECT: higher impact elasticity and longer working life of tubes.

37 cl, 5 dwg, 3 tbl, 7 ex

FIELD: polymer materials.

SUBSTANCE: invention relates to soft polymer compositions containing large amount of inorganic fillers. Composition according to invention contains 20-60% heterophase polyolefin composition (I) and 40-80% inorganic filler (II) selected from fire-retardant inorganic fillers and inorganic oxides or salts. Moreover, heterophase polyolefin composition I includes 8 to 25% crystalline polymer component (A) selected from propylene homopolymer, propylene copolymers, and mixtures thereof, and 75 to 92% elastomer fraction (B) composed of at least elastomeric propylene 04 ethylene copolymer with 15-45% of at least one α-olefin. Heterophase polyolefin composition I is characterized by solubility in xylene at room temperature above 50%, while intrinsic viscosity of xylene-soluble fraction ranges between 3.0 and 6.5 dL/g. Polyolefin compositions of invention find their use as substitute of plasticized polyvinylchloride.

EFFECT: increased plasticity of materials at the same good thermoplastic properties.

15 cl, 1 dwg, 2 tbl, 10 ex

FIELD: biopolymers.

SUBSTANCE: invention relates to production of plastic masses based on ethylene and vinylacetate copolymer for mould products useful in food processing industry and agriculture. Claimed composition contains 50-68.7 mass % of ethylene and vinylacetate copolymer, biologically degradable filler containing rye flour in amount of 30-48,7 mass % and additives such as surfactant in amount of 0.1 mass %, maize amylacetate in amount of 1 mass %, and 0.2 mass % of methylcellulose.

EFFECT: new biologically degradable composition.

2 tbl

FIELD: polymeric materials.

SUBSTANCE: invention relates to polymeric composition materials, namely, to composition of polymeric composition of multifunctional modifying agent. Proposed multifunctional modifying agent comprises the following components, wt.-%: copolymer of ethylene with vinyl acetate, 2-20; calcium carbonate, 2-25; oleic acid amide, 2-20, and high pressure polyethylene, up to 100. Invention provides expanding functional properties of modifying agent and enhancing technological tasks in processing polymers. Invention can be used in making articles by extrusion or under pressure in casting machines of auger type and nontoxic materials using for package of foodstuffs an/or medicinal preparations.

EFFECT: valuable properties of modifying agent.

6 tbl, 6 ex

FIELD: polymer materials.

SUBSTANCE: composition comprises polyolefin A, containing anhydride function and having viscosity at least 20 g/10 min measured at 190°C and loading 2,16 kg, and epoxy function-containing product B destined for cross-linking polyolefin A. Relative proportions of A and B are such that for each epoxy function there are from 0.1 to 1.5 anhydride functions. Composition can be used in slush molding process, in thermal molding of sheets, or in on-rod casting process.

EFFECT: increased flowability resistance and wear resistance.

6 cl, 1 tbl, 6 ex

FIELD: polymer materials.

SUBSTANCE: invention relates to cable engineering and more particular to halogen-free polymer compositions for cable insulation and shells. Composition contains, wt %: magnesium hydroxide 40-70, phenol-formaldehyde novolac resin 0.5-4, zinc borate 1.5-5, polyethylene wax 2-5, Irganox 1330 0.05-2, Irganox METHOD 1024 or Lowinox MD24 0.1-0.5, and ethylene-vinyl acetate copolymer - the rest.

EFFECT: improved mechanical characteristics and resistance to copper ions attack.

2 tbl

FIELD: adhesives.

SUBSTANCE: invention relates to ethylene copolymers-based adhesive compositions used as adhesives when depositing polymeric protective coating on metallic surface utilizing extrusion and co-extrusion techniques and winding thermosetting multiple-layer adhesive tape. Using composition containing ethylene/vinyl acetate copolymer, silicate filler, and modifying agent (resin OSR-100) results in providing preservation of high adhesion and strength characteristics and resistance to cathode peeling when lowering metal temperature heating to 100-130°C in double-layer coating structure and also ensuring high values of adhesion strength for ground epoxide layer in triple-layer coating structure.

EFFECT: enhanced adhesive properties in multiple-layer coating applications.

3 tbl

FIELD: rubber industry, in particular polymer composition.

SUBSTANCE: claimed composition contains (mass %): rubber 100; sulfur vulcanizating agent 2.5-3.5; promoter group 0.8-2.0; vulcanization activator 10-20; filler such as carbon black 50-70; plasticizer 2-3; anti-aging agent 3-6; ethylene/vinyl acetate copolymer containing 26-30 % of vinyl acetate 3-5.

EFFECT: copolymer with increased tear resistance.

2 tbl

Medical container // 2311165

FIELD: medical facilities.

SUBSTANCE: invention provides medical container, which is used to fill with blood, drug, and the like. Container is manufactured from film or sheet having at least one high-density polyethylene layer and polymer layer containing polyolefin composition, wherein said polyolefin composition comprises (A) at least one propylene-containing polymer selected from group consisting of (A1) propylene-containing polymer composition in the form of mixture of (A11) propylene polymer and (Q12) elastomeric ethylene-propylene copolymer and (A12) propylene-containing block-copolymer; and (B) ethylene-containing copolymer containing ethylene and at least one α-olefin having 4 or more carbon atoms and characterized by refractory index of xylene-soluble fraction of this polyolefin composition equal to 1.480-1.495; said high-density polyethylene containing 70% or more high-density polyethylene having density 0.950 g/cc or higher, while high-density polyethylene layer being disposed on at least one (inner or outer) side of container.

EFFECT: achieved temperature resistance high enough to enable sterilization at 121°C or higher and manifested excellent clearness, shock strength, elasticity, and resistance to conglomeration.

5 cl, 3 tbl, 14 ex

FIELD: chemical industry; metal working industry; methods of production of the adhesive composition used for deposition of the coatings on the metal surfaces.

SUBSTANCE: the invention is pertaining to the methods of production of the adhesive composition intended for deposition on the steel surface as the primer of the adhesive intermediate layer deposited on the steel surfaces under the polyolefin protecting coatings. The technical problem of the invention is the reduced duration of the contact of the adhesive composition melt with the surface of the metal at conservation of the high adhesive strength. The technical problem is being solved by that the method provides for the combined mixing of the ethylene copolymer and vinyl acetate or the combination of the copolymers of the ethylene and vinyl acetate differing in the contents of the vinyl acetate groups with polyisocyanate, caoutchouc and the filling agent. Premix the polyisocyanate containing of no less than two isocyanate groups with the filling agent consisting of the talcum or the mica in the conditions, when the polyisocyanate is in the liquid state, with the subsequent joint mixing of all the components. At that select the copolymer of ethylene and vinyl acetate with the contents of the vinyl acetate groups from 10 up to 45 %.

EFFECT: the invention ensures the reduced duration of the contact of the adhesive composition melt with the surface of the metal at conservation of the high adhesive strength.

1 tbl, 10 ex

FIELD: polymeric materials.

SUBSTANCE: invention relates to polymeric composition materials, namely, to composition of polymeric composition of multifunctional modifying agent. Proposed multifunctional modifying agent comprises the following components, wt.-%: copolymer of ethylene with vinyl acetate, 2-20; calcium carbonate, 2-25; oleic acid amide, 2-20, and high pressure polyethylene, up to 100. Invention provides expanding functional properties of modifying agent and enhancing technological tasks in processing polymers. Invention can be used in making articles by extrusion or under pressure in casting machines of auger type and nontoxic materials using for package of foodstuffs an/or medicinal preparations.

EFFECT: valuable properties of modifying agent.

6 tbl, 6 ex

FIELD: biopolymers.

SUBSTANCE: invention relates to production of plastic masses based on ethylene and vinylacetate copolymer for mould products useful in food processing industry and agriculture. Claimed composition contains 50-68.7 mass % of ethylene and vinylacetate copolymer, biologically degradable filler containing rye flour in amount of 30-48,7 mass % and additives such as surfactant in amount of 0.1 mass %, maize amylacetate in amount of 1 mass %, and 0.2 mass % of methylcellulose.

EFFECT: new biologically degradable composition.

2 tbl

FIELD: polymer materials.

SUBSTANCE: invention relates to soft polymer compositions containing large amount of inorganic fillers. Composition according to invention contains 20-60% heterophase polyolefin composition (I) and 40-80% inorganic filler (II) selected from fire-retardant inorganic fillers and inorganic oxides or salts. Moreover, heterophase polyolefin composition I includes 8 to 25% crystalline polymer component (A) selected from propylene homopolymer, propylene copolymers, and mixtures thereof, and 75 to 92% elastomer fraction (B) composed of at least elastomeric propylene 04 ethylene copolymer with 15-45% of at least one α-olefin. Heterophase polyolefin composition I is characterized by solubility in xylene at room temperature above 50%, while intrinsic viscosity of xylene-soluble fraction ranges between 3.0 and 6.5 dL/g. Polyolefin compositions of invention find their use as substitute of plasticized polyvinylchloride.

EFFECT: increased plasticity of materials at the same good thermoplastic properties.

15 cl, 1 dwg, 2 tbl, 10 ex

FIELD: chemistry.

SUBSTANCE: polymer composition contains low- and high-molecular polyethylene components, the composition basically having a single peak of lamella width percentile curve and PENT greater than 1000 hours at 80°C and 2.4 MPa according to ASTM F1473. The process has several variants allowing production of tubes with enough viscosity to resist shock during laying or afterward; and with extra long working life under gas or water pressure, especially resistant to environmental stress cracking and to creep under internal pressure.

EFFECT: higher impact elasticity and longer working life of tubes.

37 cl, 5 dwg, 3 tbl, 7 ex

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