Phenolic resin for use in the phenolic resin component of a two-component binder system for the polyurethane cold box process, wherein the phenolic resin comprises: (a) a resol having the following structural units: where at one, two or three of positions 2, 4 and 6, instead of a bond to hydrogen, there is a bond to a further structural unit of the resol, one or more structural units of the formula where the substituent R is an (a2-i) substituted or unsubstituted, (a2-ii) aliphatic, (a2-iii) branched or unbranched, (a2-iv) saturated or unsaturated radical having a total of 5 to 35 carbon atoms, including any substituents, and where at one, two or three of positions 2, 4 and 6, instead of a bond to hydrogen, there is a bond to a further structural unit of the resol, one or more structural units of the formula where the substituent R' is substituted at position 2 or 4 and is an (a3-i) substituted or unsubstituted, (a3-ii) aliphatic, (a3-iii) branched or unbranched, (a3-iv) saturated or unsaturated radical having a total of 1 to 15 carbon atoms, including any substituents, and where at one, two or three of the remaining positions 2, 4 and 6, instead of a bond to hydrogen, there is a bond to a further structural unit of the resol, as a link connecting two phenol rings, as a link connecting two phenol rings. (a) a resol having the following structural units: where at one, two or three of positions 2, 4 and 6, instead of a bond to hydrogen, there is a bond to a further structural unit of the resol, one or more structural units of the formula where the substituent R is an (a2-i) substituted or unsubstituted, (a2-ii) aliphatic, (a2-iii) branched or unbranched, (a2-iv) saturated or unsaturated radical having a total of 5 to 35 carbon atoms, including any substituents, and where at one, two or three of positions 2, 4 and 6, instead of a bond to hydrogen, there is a bond to a further structural unit of the resol, one or more structural units of the formula where the substituent R' is substituted at position 2 or 4 and is an (a3-i) substituted or unsubstituted, (a3-ii) aliphatic, (a3-iii) branched or unbranched, (a3-iv) saturated or unsaturated radical having a total of 1 to 15 carbon atoms, including any substituents, and where at one, two or three of the remaining positions 2, 4 and 6, instead of a bond to hydrogen, there is a bond to a further structural unit of the resol, as a link connecting two phenol rings, as a link connecting two phenol rings. where at one, two or three of positions 2, 4 and 6, instead of a bond to hydrogen, there is a bond to a further structural unit of the resol, one or more structural units of the formula where the substituent R is an (a2-i) substituted or unsubstituted, (a2-ii) aliphatic, (a2-iii) branched or unbranched, (a2-iv) saturated or unsaturated radical having a total of 5 to 35 carbon atoms, including any substituents, and where at one, two or three of positions 2, 4 and 6, instead of a bond to hydrogen, there is a bond to a further structural unit of the resol, one or more structural units of the formula where the substituent R' is substituted at position 2 or 4 and is an (a3-i) substituted or unsubstituted, (a3-ii) aliphatic, (a3-iii) branched or unbranched, (a3-iv) saturated or unsaturated radical having a total of 1 to 15 carbon atoms, including any substituents, and where at one, two or three of the remaining positions 2, 4 and 6, instead of a bond to hydrogen, there is a bond to a further structural unit of the resol, as a link connecting two phenol rings, as a link connecting two phenol rings.