SUPER-PLASTICIZER RETARDING SETTING Russian patent published in 2005 - IPC

FIELD: polymers, building materials.

SUBSTANCE: invention relates to a super-plasticizer based on naphthalene-formaldehyde. Invention proposes a super-plasticizer based on polymethylene naphthalene sulfonates (PNS) retarding setting wherein block-copolymer of PNS and technical lignosulfonates taken in their ratio = 1:(0.33-3). Indicated block-copolymer is prepared by condensation of oligomeric PNS comprising the reactive hydroxymethylene group with lignosulfonates in strong acid medium at 1-2 h for 110-115°C up to the equilibrium molecular-mass distribution index. Formation of oligomeric PNS is carried out by preliminary condensation of naphthalene sulfonic acid and formaldehyde at 125-130°C for 45-75 min in the presence of the high concentration of hydroxymethylated oligomeric intermediate substances in the reaction medium. The super-plasticizer comprises additionally a surface-active substance with the foam-quenching or air-removing effect in the mass ratio of indicated block-copolymer and indicated surface-active substance = 1:(0.002-0.005). Invention provides preparing the additive providing the enhanced working ability of plasticized concrete mixtures being without effect on the hardening kinetics and the concrete strength.

EFFECT: improved and enhanced properties of agent.

4 cl, 4 tbl