Block-shaped isotridecanol alkoxylates as low-foam or foam-suppressing surfactants

The invention concerns the use as low-foam or antifoaming surfactants, in particular in washing and cleaning agent formulations and for chemical - technical applications, of block-form iso-tridecanolalkoxylates of the formula (I): R-O-(CmH2mO)x-(CnH2nO)y-H, in which: R designates an iso-tridecyl group; m stands for the number 2 and simultaneously n stands for 3 or 4; or m stands for the number 3 or 4 and simultaneously n stands for 2; and x and y, independently of each other, designate numbers from 1 to 20, wherein, if m = 2/n = 3 or 4, the variable x is greater than or equal to y.