FIELD: chemistry.
SUBSTANCE: present invention relates to a group of inventions: modified polytetrafluorethylene, a molded product, and a method for the production of stretched porous material. Modified polytetrafluorethylene contains polymer having links based on tetrafluoroethylene and polymer having links based on monomer not containing fluor. Monomer not containing fluor is monomer of the formula: CH2=CR1-CO-O-R3. R1 is a hydrogen atom or an alkyl group, R3 is an alkyl group having from 2 to 6 carbon atoms. The ratio of endothermic amount of R is from 0.65 to 2.50. Measurements of endothermic amount of R are carried out using a differential scanning colorimeter (Pyris 1 DSC produced by Pekin Elmer Co., Ltd.) having a temperature calibrated using indium and zinc as standard samples. Modified polytetrafluorethylene without a history of heating to a temperature of at least 300°C is used, measurements are carried out using the differential scanning colorimeter at a heating speed of 20°C/min, a differential thermal curve is obtained; on the resulting differential thermal curve, a temperature 2.5°C lower than a temperature of an endothermic peak Tp°C, above 340°C, is taken as a temperature Tm°C; and endothermic amount S1 in a temperature range from 310°C to the temperature Tm°C and endothermic amount S2 in a temperature range from the temperature Tm°C to 360°C are obtained; after that, the ratio of endothermic amount S2 to endothermic amount S1 is calculated as the ratio of endothermic amount R. The molded product is obtained by extrusion molding of paste of modified polytetrafluorethylene. The molded product is an extruded bar. The method for the production of stretched porous material includes extrusion of paste of modified polytetrafluorethylene to obtain the extruded bar, and stretching of the extruded bar to obtain stretched porous material. Stretched porous material is a stretched bar.
EFFECT: development of modified polytetrafluorethylene with excellent thermal resistance.
9 cl, 4 dwg, 1 tbl, 11 ex
