Seleção de critérios para a especificação de pastas celulósicas branqueadas de eucaliptos na fabricação de papéis para impressão offset
The purpose of this work was to analyze the characteristics of some eucalypts pulps available in the market, aiming to understand their influence in the properties of the offset papers. Another objective of this work was to show alternatives to reduce the number of laboratory tests in the pulp sp...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | Portuguese |
| Published: |
Universidade Federal de Santa Maria
2000-01-01
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| Series: | Ciência Florestal |
| Online Access: | http://www.redalyc.org/articulo.oa?id=53400104 |
| Summary: | The purpose of this work was to analyze the characteristics of some eucalypts pulps available
in the market, aiming to understand their influence in the properties of the offset papers. Another
objective of this work was to show alternatives to reduce the number of laboratory tests in the pulp
specifications. Thirteen (13) market pulps (Brazilian and international pulps) were analyzed and the
tests applied were as follows: intrinsic viscosity, alkali solubility at 5%, coarseness, numbers of fibers
per gram of pulp, average length of fibers, fine fraction by the Dynamic Paper Chemistry Jar (DPCJ),
drainability by Schopper Riegler, before refining. Other tests, such as: tensile index, stretch, burst
index, tear index, bulk, air resistance, opacity and absorption of water by cappilarity (Klemm) were
performed for each type of pulp before refining and for refining levels of 25 ºSR, 30 ºSR, 40 ºSR and
55 ºSR. No evidence of the influence of S5 and intrinsic viscosity was observed at the range of the
market pulp properties variation. The Brazilian pulps presented higher initial drainability and required
lower PFI revolutions to the same level of refining in comparison to the international pulps. The
initial average values of strength indexes: tensile, stretch, burst and tear were higher to the Brazilian
pulps. However, this situation was changed at 25 ºSR and other levels of drainability. Due to the
higher number of correlations at 30 ºSR, this level of drainability was chosen to determine the pulp
characteristics profile. At this level, international pulps showed better values of tensile and tear
index, but a higher energy consumption and a lower opacity in comparison to the Brazilian pulps. In
addition, this paper suggested the concentration of the lab technical evaluation of pulps on the
analysis of opacity, tensile and tear indexes. Such procedure should reduce the number of lab tests as
well. |
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| ISSN: | 0103-9954 1980-5098 |