3 heat kg cm 2 at 250 u00b0 c shake out property 10 12 14 12 22 25 22 20 24 25 22 29 30 29 33 31 times in a kettle fitted with a reflux cooler 1000 parts of phenol 1795 parts of 37 formalin 160 parts of 28 aqueous ammonia and 60 parts of 50 sodium hydroxide solution were added the temperature of the mixture was gradually elevated when the temperature reached 96 u00b0 c after 30 minutes 39 reflux 40 parts of ethylene bis stearic amide was added after dehydrating the mixture under vacuum until the temperature reached 85 u00b0 c it was dumped from the kettle cooled rapidly and successively ground to obtain 1100 parts of a coarse ground resole type phenolic resin 7000 parts of sanei silica sand preheated at 130 u00b0 140 u00b0 c was charged to a whirl mixer aromatic bromide i 0 07 parts was added thereto and the mixture was mixed for 20 seconds 140 parts of lubricant containing resole type phenolic resin obtained from preparation example 3 was added mixing for 30 minutes then 105 parts of cooling water were added the mixture was mixed until the coated sand crumbled 7 parts of calcium stearate was added thereto through 30 seconds 39 mixing and the mixture was discharged and aerated to obtain a coated sand this experiment was repeated two additional times adding 7 parts and 42 parts of the aromatic bromide respectively thus three types of coated sand were obtained example 2 was repeated except 28 parts of aromatic bromide ii was employed as the bromide a resin coated sand was produced by the procedure of example 2 except no aromatic bromide was added respective characteristics including the shake out.