| 摘要 |
A process for production of a substantially water soluble or water dilutable sulphonated resole type phenolic resin is provided. The process comprises subjecting at least one phenolic compound and formaldehyde, at a molar ratio phenolic compound to formaldehyde of 1:1.5 to 1:5, to a condensation reaction in the presence of an effective amount of at least one basic catalyst. The condensation reaction is terminated when a free formaldehyde content of 1-10 % by weight is obtained and yielded condensation product is subsequently subjected yielded to a sulphonation, which sulphonation comprises adding 1-10 % by weight of pyrosulphite. The sulphonation is performed at a temperature of 30-60 DEG C and maintained for a time period of at least 15 minutes. |
