METHOD FOR PRODUCING HIGH-STRENGTH AND HEAT-RESISTANT FOAMED PLASTICS Russian patent published in 2022 - IPC C08J9/10 C08L63/00 C08L61/04 C08K5/00 C08K5/3492 

FIELD: polymers.

SUBSTANCE: invention relates to the field of production of foamed plastics based on thermosetting polymer compositions providing a possibility of manufacturing heat, sound and electrically insulating products, as well as elements of radiotransparent shelters. Method for producing high-strength and heat-resistant foamed plastics, including the production of a product based on mixing a novolak phenol formaldehyde resin with an epoxy mixture and introducing a chemical gasifying agent - 2,2'-azobisisobutyronitrile. A ground powdered mixture of solid high molecular weight epoxy diane resin with a molecular weight of 1,600, 3,500 or 5,000 and a content of epoxy groups of 6%, 3% or 1%, respectively, (A) and solid triglycidyl isocyanurate (B) in the ratio A : B from 5:95 to 25:75 wt. pts. is therein used as an epoxy mixture, and a product with a content of free phenol of no more than 2% at a ratio of epoxy mixture : novolak phenol formaldehyde resin from 70:30 to 50:50 wt. pts. is used as a novolak phenol formaldehyde resin. The product is produced by processing the powdered mixture on heated friction rollers at a temperature of the rolls from +70 °C to +110°C for 8 to 20 minutes, followed by cooling the rolled mass and further grinding in a ball mill jointly with a chemical gasifying agent introduced in an amount from 1 to 5 wt. pts. per 100 wt. pts. of the resin composition, followed by foaming the finished semi-product in two stages in restraining moulds: at the first stage, at a temperature of 105÷115°C for 40÷60 minutes, and at the second stage, at a temperature of 160÷180°C for 20÷40 minutes.

EFFECT: production of foamed plastic with high heat resistance, resistant to long-term impact of temperatures up to +300°C and short-term impact of temperatures up to +400°C, as well as impact of open flame, combined with high strength and dielectric properties, resistance to impact of an electric arc, with the possibility for production using simple industrial production equipment.

1 cl, 1 tbl, 3 ex