Abstract: A method for preparing a conductive thermoplastic resin composition or an electric conductor includes the step of kneading (a) conductive resin master batch pellets of conductive carbon black and a thermoplastic resin in which the conductive carbon black accounts for 5 to 50% by weight relative to the total amount 100 parts by weight of the conductive carbon black and the thermoplastic resin, (b) a thermoplastic resin in a weight ratio: (a+b)/(a) ranging from 1.01 to 1.5. This method permits the production of a conductive carbon black-containing conductive resin composition and an electric conductor which show stable conductivity even within a high resistance region (having a surface resistivity ranging from 10.sup.6 to 10.sup.16 .OMEGA.), wherein the control of the conductivity is difficult.

Abstract: A method for preparing a conductive thermoplastic resin composition or an electric conductor includes the step of kneading (a) conductive resin master batch pellets of conductive carbon black and a thermoplastic resin in which the conductive carbon black accounts for 5 to 50% by weight relative to the total amount 100 parts by weight of the conductive carbon black and the thermoplastic resin, (b) a thermoplastic resin in a weight ratio: (a+b)/(a) ranging from 1.01 to 1.5. This method permits the production of a conductive carbon black-containing conductive resin composition and an electric conductor which show stable conductivity even within a high resistance region (having a surface resistivity ranging from 10.sup.6 to 10.sup.16 .OMEGA.), wherein the control of the conductivity is difficult.

Abstract: An electroconductive resin composition comprising (i) 100 parts by weight of thermoplastic resins and/or thermosetting resins and (ii) 15 to 150 parts by weight of (a) carbon black having a DPB oil absorption amount of 400 ml/100 g or more and (b) expanded graphite having an average particle size of 40 .mu.m or more, wherein the expanded graphite content is 40 to 90% by weight of the total amount of the carbon black and the expanded graphite.

Abstract: An electrically conductive resin composition comprising:(i) a resin;(ii) a metallic powder;(iii) a diphosphonic acid derivative; and(iv) a hydroxyl-containing compound; wherein the weight ratio of the compound (i)/the component (ii) is 30/70 to 85/15 and the amounts of the components (iii) and (iv) are 0.5 parts by weight or more and 0.08 parts by weight, respectively, based on 100 parts by weight of the components (i) and (ii).

Abstract: An electrically conductive thermoplastic resin and coating composition comprising a diphosphonic acid derivative having the formula: ##STR1## wherein R represents an alkyl or aryl group and M.sup.1 to M.sup.4 independently represent hydrogen or a cation.The electrically conductive thermoplastic resin composition has excellent electrical conductivity and retains the electrical conductivity for extended periods without using expensive noble metals. Furthermore, the electrically conductive coating composition provides an excellent electrical conductivity and shielding property retention without using expensive noble metals.