| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain waste paper pulp suitable for a back face layer of a paperboard having improved strength and surface property of the paper by breaking waste paper containing coated paper and subjecting to blending treatment and classifying treatment. SOLUTION: Waste paper pulp obtained by breaking with a pulper the waste paper containing coated paper such as printed waste paper in which a newspaper or a magazine is mixed is adjusted to a range of 25-35 wt.% of pulp concentration and is subjected to blending treatment with a PFI mill, etc. Then, pulp concentration is diluted to 1.5 wt.% with a large amount of water and subjected to classifying treatment with a sulfite pulp filter, and subjected to a beating treatment, as necessary, to obtain the objective waste paper pulp for a back face layer of a paperboard.</p> |
