| 摘要 |
PROBLEM TO BE SOLVED: To provide bleached kraft paper having high strength and adequate printability, in particular bleached kraft paper that is suitable for a multi-wall paper sack.SOLUTION: The bleached kraft paper satisfies the following conditions (1) to (8): (1) 50-70 mass% of hardwood bleached kraft pulp and 30-50 mass% of softwood bleached kraft pulp are contained as raw material pulp; (2) freeness of the hardwood bleached kraft pulp is 300-450 ml and freeness of the softwood bleached kraft pulp is 500-600 ml; (3) 1.0% or more calcium carbonate is added as a filler to control an ash content to be 0.5-5.0%; (4) a surface treatment agent containing an adhesive as a main component is applied in an amount of 0.2-1.0 g/mper one side; (5) an external sizing agent and a surface sizing agent are used to control Stockigt sizing degree to be 30 seconds or longer; (6) whiteness is 75% or more; (7) oil absorbency is 40-80 seconds; and (8) smoothness is 30-80 seconds. |
