Board grades

The cahper is the thickness in p.m of a single sheet measured under specified conditions (TAPPI T411). CaUpers for a number of common paper and board grades are capacitor tissue, 7.6 p.m facial tissue, 65 p.m newsprint, 85 p.m offset bond, 100 p.m linerboard, 230—640 p.m and book cover, 770-7600 pm. 

Solid board materials may be converted into collapsible or rigid cartons or rigid fiberboard (outers). International codes exist for solid and corrugated fi-berboards in terms of design (style). These cases are specified by style, internal dimensions, board grade, and quality. 

A total import of all required virgin fibre-based paper and board grades from other European countries to cover the German demand or from outside Europe to cover the European demand would currently fail due to unavailable capacities. 

The reduction of the mineral oil input during paper production by utilisation of mineral oil-free additives should be the responsibility of each paper manufacturer regardless of the type of the produced paper or board grade. This would be a contribution to keep the recycling loops as much as possible clean. 

Schwarz M (2000) Design of recycled fiber processes for different paper and board grades. In Gottsching L, Pakarinen H (eds) Recyled fiber and Deinking. Fapet Oy, Helsinki (Chap. 6)... 

Cross-cut to 1-4 pieces, depending on board grade and length (1 8 or 2.4m), Reject all pieces that do not contain at least one minimum sized blank... 

Cylinder machines are used for heavy board grades, with grammages of 350 g m or more. The products are multilayered and generally have high grade liner on their outer faces while the interior may use unbleached recycled fibre. Drainage on a Fourdrinier would be too slow resulting in uneconomic machine speeds. 

The use of paraffin wax emnlsions is very rare, bnt they have been used for highly water-resistant grades of board. The anionic wax dispersion is precipitated onto the fibre with alum. It generally relies on the very high self-retention of high basis weight board grades for efficiency and, because it is not always correctly orientated to the fibre surface, is much less efficient than conventional sizes. 

The paper machine in this exercise manufactures two-ply kraft liner board grade packaging paper using unbleached long-fibre kraft pulps. The refining operation of the stock approach system of the top ply comprised two 42 double-disc refiners... 

Mixed grades comprising always a mixture of various paper and board grades used for the production of packaging paper and board. 

The wide variety of specific demands that are placed on the different paper and board grades cannot be fulfilled with natural raw materials alone. It needs chemical additives with very specific performances, the so-called specialty chemicals . 

More details about coating color formulations depending on the specific paper and board grades are mentioned in Section 7.5. 

Paulapuru, H., Papermaking and Technology, Book 18, Paper and Board Grades,... 

M. Schwarz, Design of Recycled Fiber Processes for Different Paper and Board Grades, Paper Making Science and Technology, Book 7, Recycled Fiber and Deinking, Fapet OY, Helsinki, 2000, Ch. 6, p. 211. 

Coated board grades range from one- to five-ply boards and can consist of virgin fibers and/or recycled fibers. The most important properties are high bulk, stiffness and smoothness. The board is usually one-side coated. In some cases, however, it can also be two-sided. 

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