| 摘要 |
1394282 Paperboard UNION CARBIDE CORP 20 July 1972 [21 July 1971 29 March 1972] 34110/72 Heading D2B [Also in Division C3] A hard, rigid board of paper pulp fibres bonded by a phenolic resin is made by preparing a mixture a kraft paper pulp and an aqueous dispersion comprising a phenol-formaldehyde resole resin, gum arabic and guar gum, adjusting its pH to 4.5 with alum, collecting the resin-pulp mixture on a 100 mesh screen to form a sheet which is then dried at room temperature. The dried sheet is then hot pressed. |
