The invention relates to a preparation method of resin and in particular relates to a preparation method of resin for
casting. The preparation method of the resin for
casting is characterized by comprising the following steps: adding furfuraldehyde,
cardanol,
urea and an alkali catalyst into a reactor, preserving heat, carrying out a reaction, and then cooling to
room temperature, thus obtaining resin; adding the resin, furfuraldehyde and an acid catalyst into the reactor, controlling the
reaction temperature at 70-100 DEG C, preserving heat and carrying out a reaction for 1-3 hours, transferring reaction products into a reduced pressure
distillation kettle, carrying out reduced pressure
distillation and
dehydration for 1-2 hours under the conditions that the temperature is 50-80 DEG C and the vacuum degree ranges from minus 0.05MPa to minus 0.08MPa, cooling to
room temperature, regulating pH value to be 7.0-7.5, then adding 6-10 parts by weight of
silicon compound and 15-20 parts of
dibasic ester, and uniformly stirring, thus obtaining the resin for
casting. The preparation method of the resin for casting is unique and environment-friendly, and the
moisture resistance is better than that of the traditional
furan resin.