The 1X'OP8rti8 aDd cb8Djcaj ~ of lUU-forma1debyde (UF) rSI8 syntbeBized by three differ-. procedure8 W8e in~..-The procedur8 employed W8e: 1) metbylolation und8' the cOIxIiti~ of pH 8 aDd a fonllalde-hyde/1UU (F /U) molar ratio of 2, followed by condenutioo at pH 5 aDd by tile additional iJKorpora. non of ur8. 2) cond8llation w.-tile conditiorw of pH 4.5 aDd a FlU molar ratio of 2.5, folio'" by tile additional incorporation of urea. 3) condenution urxIer tile COrM!itiOl8 of pH 1 aDd a F /U molar ratio of 3. foUo'" by tile additional i~tioo of urea. Proced\In8 1) aDd 2) .ave resi1W of limilar pr,)P6'.-Jei: die boIIdinI ma.th of the rain syntbe.-ized by ProcedIn 1) wu 1Ii8ht\" hiIII8' than that of the r8a 1JntI8-by PrOC8klre 2). whereu the formaJdehyde SDi_~ of tile fon!*' reaD wu slilbtlJ hiibel' than that oftbe latter r8in. The boMiII8 mewtb of tile r8n.~~-by procedure 3) wu far inferior to tbO8 of tile other two reIi-. HoW89W, thi8 ran !bowed vwy little formaldehyde emi8ioa. '~-NMR (Carboa 13 nlM:lear maInetic reeonance) analysis sbowed that braIM:hed, ~ ilM:rea8d .. the pH of the condenution step lowered. In particular, methylene link... bet~ tertiary nitroaen atoms ... fonned by Procedure 3). The resin syntb8zed by Procedure 3) aIao contail.t ID'OI8, aDd bad a far 8DalIer amoUnt of methylolll'OUP than tile oth8' two _ra K~ : ur8 re8iI8o 8YDrJ.tic colMtitior-. chemical ~ boI1dinc ItreII8th. formaJdehyde emi8oa.