METHOD OF HARDENING COMPOSITION MATERIALS ON THE BASE OF PHENOLFORMALDEHYDE BINDER Russian patent published in 1995 - IPC

FIELD: chemistry. SUBSTANCE: components of the material are heated from room temperature to 108-112 C at rate v₁= 0,8-1,2^°C/min of 0.8-1.2 C /min and held for 1.3-1.7 hours. Then the components are heated till reaching temperature of maximal hardening of samples at rate v₂= 1,3-1,7^°C/min of 1.3-1.7 C /min at permanent measurement of electric conductivity G and the loss tangent of a dielectric tgδ. Heating is stopped at temperature of maximal hardening of the sample when values G and G and tgδ are reached during some period of time. Characteristics of the material are the following: separation strength 34,46 kgs/сm³, separation module is 5323 kgs/сm³, strength at shifting along glue band is equal to 6,2 kgs/сm³, compressive strength is equal to 10,7 kgs/сm³, degree of hardening is equal to 96%, time of thermal treatment - 3 hours and 40 minutes. EFFECT: improved efficiency. 3 tbl