RU2003112220A - POLYETHYLENE FORMING WEIGHT, SUITABLE AS MATERIAL FOR PIPES WITH IMPROVED TECHNOLOGICAL PROPERTIES - Google Patents

Claims (13)

1. The polymer molding material from the first ethylene polymer (A) and the second ethylene polymer (B), especially suitable for the manufacture of thick-walled large-caliber pipes, characterized in that the molding material contains the first ethylene polymer (A) in an amount of from 55 to 75 wt.% and a second ethylene polymer (B) in an amount of from 25 to 45 wt.% each, based on the total weight of the molding material, the first ethylene polymer (A) being a copolymer of ethylene with 1-olefin with a total number of C atoms from 4 to 10 as a comonomer and with a comonomer content in the region from 0.2 to 5 wt.% based on the weight of the first ethylene polymer (A) with a wide bimodal molecular weight distribution, and the second ethylene polymer (B) is a copolymer of ethylene and 1-olefin units with the number C -atoms from 4 to 10, having a bimodal molecular weight distribution, which is different than the molecular weight distribution of the first ethylene polymer (A). 2. The polymer molding material according to claim 1, characterized in that it is obtained by mixing the components of the mixture obtained separately from each other, the first ethylene polymer (A) and the second ethylene polymer (B), in an extruder in the form of an extrusion mixture. 3. The polymer molding material according to claim 1 or 2, characterized in that it preferably contains a first ethylene polymer (A) with a density (measured at a temperature of 23 ° C) of from 0.94 to 0.96 g / cm ³ and a wide bimodal molecular weight distribution, for which the ratio of the weight of the low molecular weight fraction to the weight of the high molecular weight fraction is in the range from 0.5 to 2.0, preferably from 0.8 to 1.8. 4. The polymer molding material according to one of claims 1 to 3, characterized in that the first ethylene polymer (A) contains other units of a comonomer selected from the group consisting of 1-butene, 1-pentene, 1-hexene, 4-methylpentene- 1 or mixtures thereof, in an amount of from 0.2 to 4.5 wt.%. 5. The polymer molding material according to one of claims 1 to 4, characterized in that it contains a second ethylene polymer (B) obtained as a mixture in a reactor in the presence of a Ziegler catalyst and containing an ultra-high molecular weight ethylene homopolymer as component (B ¹ ) in in an amount of 15 to 40 wt.% and a low molecular weight copolymer in an amount of 60 to 85 wt.% with 1-butene as a comonomer, in an amount of 1 to 15 wt.%, as a component (B ² ) based on the total weight a second ethylene polymer (B). 6. The polymer molding material according to claim 5, characterized in that the ultra-high molecular weight ethylene homopolymer of component (B ¹ ) has a characteristic viscosity, designated VZ ^B1 , in the range from 1000 to 2000 cm ³ / g, and the low molecular weight homopolymer of component (B ² ) has the intrinsic viscosity indicated by VZ ^B2 in the range of 80 to 150 cm ³ / g. 7. The polymer molding material according to one of claims 1 to 6, characterized in that it has a fracture toughness aFM greater than / equal to 10 kJ / m ² . 8. The polymer molding material according to one of claims 1 to 7, characterized in that it is characterized by resistance to cracking FNST≥150 hours 9. The polymer molding material according to one of claims 1 to 8, characterized in that the shear viscosity measured at 0.001 rad / s is ≥2.0 · 10 ⁵ Pa · s, preferably ≥2.7 · 10 ⁵ Pa · from. 10. The polymer molding material according to one of claims 1 to 9, characterized in that the ratio of shear viscosities of the molding material η _(0.001) / η _{(100) is} greater than / equal to 100. 11. High-strength pipe from the molding material according to one of claims 1 to 10, characterized in that the ethylene polymer A contains comonomers with 4-6 carbon atoms in an amount of from 0 to 0.1 wt.% In a low molecular weight fraction and in an amount of from 2 , 5 to 4 wt.% In the high molecular weight fraction and has a melt index MFI _5/190 $\genfrac{}{}{0ex}{}{\text{about}}{\text{FROM}}$

0.35 g / 10 min. 12. The pipe of claim 10, characterized in that it is characterized by resistance to rapid crack development, measured according to ISO / DIS 13477 on a pipe of pressure class PN 10 with a diameter of 110 mm (S4-Test), greater than / equal to 20 bar. 13. The use of the pipe according to claim 11 or 12 for the transport of gases, especially for the transport of natural gas or water.