TUBE FOR HOT FLUID MEDIA Russian patent published in 2006 - IPC C08L23/04 C08L23/06 F16L9/12 

FIELD: polymer tubes for hot fluid media, such as hot water.

SUBSTANCE: proposed tube has multi-modal polyethylene having density of 0.921-0.950 g/cm³ and containing high-molecular and low-molecular fractions; density of high-molecular fraction is 0.920 g/cm³. Service life of tube before destruction at 95°C and 3.6 Mpa is 165 h as determined in accordance with DIN 16833; elasticity modulus does not exceed 900 Mpa as determined in accordance with ISO 527-2/1B. Multi-modal polyethylene is preferably bimodal polyethylene; low-molecular fraction of such polyethylene has density of 0.955-0.975 g/cm³ and high-molecular fraction has density of 0.920-0.940 g/cm³; mass ratio of low-molecular fraction to high-molecular fraction ranges from 30:70 to 55:45.

EFFECT: enhanced cracking resistance under action of stress; improved characteristics of hydraulic pressure tests at high temperatures; enhanced flexibility.

9 cl, 1 tbl, 1 ex