| 摘要 |
The chips are maintained for at least 10 mins. at a temp. of at least 50 deg. C after presteaming, preimpregnation with H2O and/or sulphite soln., washing and drying, but before final impregnation, preheating and finishing. Pref. (i) the wood chips are preimpregnated with a sulphite soln., pref. Na sulphite soln. at pH 4-11, before the intermediate standing stage; (ii) the wood chips are maintained at the required temp. during the intermediate standing stage by steam treatment; (iii) the chips are heated during or after washing and are then kept hot during the intermediate stage; (iv) the intermediate stage lasts 30-70 mins; and (v) the temp. during the intermediate stage is maintained at 50-105 deg. C (105 deg. C corresponds to a pressure of 0.2 bar above atmos. pressure). |
