Patent ID: 7718752
Filing Date: 2010-05-18
Classification: C08G

Abstract:
1. A resorcinol-formalin resin containing no inorganic salts, produced by a production process comprising: (1) adding, to a water solvent, resorcinol (A) in an amount of 20 to 150 parts by weight relative to 100 parts by weight of water, an inorganic salt (B) in an amount of 20 to 80 parts by weight relative to 100 parts by weight of water, and an organic solvent (C) having a solubility parameter of 7.0 to 12.5 and capable of dissolving the resorcinol-formalin resin in an amount of 10 to 200 parts by weight relative to 100 parts by weight of resorcinol (A), thereby forming a mixture; (2) stirring the mixture at a liquid temperature not higher than the boiling point of the organic solvent (C) to give a two-phase system containing no remaining solid matter; (3) adding a catalytic amount of an organic acid or inorganic acid (D) to the mixture formed in step (2); (4) adding 1 to 40% formalin (E) dropwise to the mixture formed in step (3) in a molar ratio of formaldehyde/resorcinol of 0.3 to 0.8 under stirring over a period of 1 to 300 minutes thereby forming a reaction system, while maintaining the reaction system at 0 to 60° C.; (5) stirring the mixture formed in step (4) for further 10 to 60 minutes after the completion of the dropwise addition to cause a liquid-liquid heterogeneous reaction to proceed; (6) allowing the reaction system to stand while maintaining it at the temperature of the reaction to separate it into two layers, which are an aqueous layer and a reaction product layer; (7) removing the aqueous layer; (8) adding an organic solvent (C) in an amount of 1 to 5 equivalents to the amount of the reaction product to the reaction product layer which is an organic solvent layer to effect dilution; (9) adding water to the reaction product layer in an amount which is half of the amount of the organic solvent; (10) stirring the reaction system after adding of said organic solvent (C) and said water while maintaining its temperature to be not higher than the boiling point; (11) separating the reaction system of step (10) into two layers, including an aqueous layer, after allowing the reaction system to stand; and then (12) removing the aqueous layer to obtain a resorcinol-formalin resin, wherein said reaction is a one-stage reaction and liquid-liquid distribution is conducted in the same reactor, and wherein the organic solvent (C) is a ketone represented by the following general formula [1]: wherein m represents 0 or 1, n represents 0 or 1, and R