substances that do not satisfy this essential condition are used solubility in the resin and cohesion characteristics are outside of the desirable range and the objections of the invention cannot be achieved representative compounds indicated by general formula i include tri 1 stearyl glycero 3 borate tri 1 2 distearyl glycero 3 borate tri monostearylpolyethyleneglycol borate tri monostearylpolypropyleneglycol borate di 1 stearyl glycero 3 phosphinic acid esters di 1 2 distearyl glycero 3 phosphinic acid esters di monostearylpolyoxyethyleneglycol phosphinic acid esters di monostearylpolypropyleneglycol phosphinic acid esters tri 1 palmityl glycero 3 borate tri 1 2 dipalmityl glycero 3 borate tri monopalmitylpolyoxyethyleneglycol borate tri monopalmitylpolypropyleneglycol borate di 1 palmityl glycero 3 phosphinic acid esters di 1 2 palmityl glycero 3 phosphinic acid esters di monopalmitylpolyoxyethyleneglycol phosphinic acid esters and di monopalmitylpolypropyleneglycol phosphinic acid esters the amount of compound indicated in general formal i that is added in the practice of this invention must be at least 0 1 by weight based upon the wweight of the resin with total amount employed being in the range of from 0 1 to 10 by weight the amount added can be selected as desired within the aforementioned range depending on the resin and foaming agent used and on the form and properties of the foamed body density mechanical properties etc however a range of from 0 3 to 7 by weight is generally especially desirable when the amount added is less than 0 1 by weight there is a marked deterioration in the external appearance of the formed body furrowing contraction and it is not possible to obtain a satisfactory formed body in addition the properties of the formed body obtained also deteriorate on the other hand when an amount in excess of 10.