| 摘要 |
1,233,231. Wood pulp. EASTMAN KODAK CO. 10 Oct., 1968 [16 Oct., 1967], No. 48127/68. Heading D2W. Wood chips are mixed with water and at least 30% by wt SO 2 (calculated on the combined weight of water and sulphur dioxide), and the temperature is raised quickly, within 2 hours, to at least 120‹C., and maintained above 120‹C until the chips are pulped, at least 30 wt% of SO 2 being maintained in the suspension for at least 5 mins after reaching 120‹C. The wood chips may be blended with a mixture comprising water and 30-80% S0 2 , the temperature of the mixture being from 120-145‹C during the blending, and the temperature of the resulting blend then maintained within this range for at least 30 mins., a 30% concentration of SO 2 being maintained for at least 15 minutes. Free or combined SO 2 may be used. The suspension may also contain 5-50 wt% of a miscible additive such as an aliphatic alcohol containing 1-5 C atoms; an aliphatic carboxylic acid containing 1-5 C atoms or a glycol. Woods pulpable by this method are:-Eastern spruce, Southern pine, Douglas fir, gumwood, White birch and alder. |
