| 摘要 |
Disclosed is a process for preparing phenol-formaldehyde thermoset resin that can contain up to 80% by weight a black liquor, preferably a sodium carbonate black liquor. Black liquor are by-products extracted from pulping process, which normally contain lignosulfonates, kraft lignin or sodium carbonate lignin as well as salts, depending on the process that is used. The use of such a black liquor permits to obtain a stable copolymerized phenol-formaldehyde thermoset resin. In the process, the black liquor is first mixed with phenol in the pressure of a base. Then, formaldehyde is added together with a base in two successive steps. The obtained thermoset resin has bonding properties that meet or exceed the CSA and ASTM requirements for the engineered forest products, such as wafer boards or oriented strand boards at pressing cycles of 16 mm per second or less.
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