METHOD OF PREPARING PHYSICALLY FOAMED POLYOLEFIN FOAMS AND HEAT-INSULATION PLASTIC FOAMS MANUFACTURED THEREFROM Russian patent published in 2005 - IPC

FIELD: polymer materials.

SUBSTANCE: invention, in particular, relates to polyolefin foams, which are resistant to temperatures as high as 160°C. Method comprises stirring and melting of polyolefin, melting range of which is 85-170°C (as measured according to differential scanning calorimetry technique at heating rate 10°C /min), or a mixture of one or several such polyolefins. Resulting homogenous mixture consists of a single individual phase with melting temperature within the range 120-160°C (measured as above). The mixture is fed into extruder being heated to melting temperature in the first section of extruder. Molten mixture is further mixed, in the second section of extruder at elevated pressure, with foaming agent containing substance, which is liquid at temperature and pressure in extruder but vaporizes when pressure is lowered. Molten mixture is then cooled to a temperature, at which liquid mixture transforms to semicrystalline phase, and extruded through in cold state through die such as to foam the mixture as a result of evaporation of foaming agent to produce foamed polyolefin.

EFFECT: increased temperature resistance of foamed polyolefin.

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