METHOD FOR TWO-STEP PRODUCTION OF POLYFUNCTIONAL COMPLEX ADDITIVE FOR CONCRETE AND MORTAR AND POLYFUNCTIONAL COMPLEX ADDITIVE Russian patent published in 2013 - IPC C04B24/24 C04B103/30 

FIELD: chemistry.

SUBSTANCE: invention relates to a composition and a method of producing a complex additive used as a property modifier for concrete and mortar produced from binding materials based on portland cement clinker. The method involves two-step production of the additive by condensation of naphthalene sulphonic acid - NKS with formaldehyde to form oligomeric polymethylene naphthalene sulphonates - PNS at the first step, polycondensation of PNS and technical lignosulphonates - LS to form a block-copolymer at the second step and adding to the obtained product a defoaming surfactant, wherein the first step for condensation of NKS with formaldehyde is carried out with preheating of the reaction mixture from 116°C to 125-127°C and feeding formaldehyde for 120-150 minutes while stirring and then holding at 125-130°C for 120-150 minutes, wherein the process is carried out at pressure of 150-250 kPa; the second step is carried out by stirring for 150-180 minutes at 118-123°C with preliminary holding of the reaction mass for 12-30 minutes at 100-105°C at atmospheric pressure and weight ratio of PNS to LS of 1:(0.28-0.32). The obtained product is treated with an alkali to pH 7-9. The complex additive for concrete and mortar obtained using said method is produced in two forms - in form of a solution or powder. The invention is developed in subclaims.

EFFECT: obtaining a polyfunctional additive with controlled plasticising air-entraining properties.

3 cl, 4 tbl