3
C.V.G. Esteves: Oxygen deligni fi ed fi bers as a greener alternative for tissue paper
Figure1: Illustrative representation of the performed kraft cooking and oxygen deligni fi cation trials. The black arrows represent the cooking extension and the white arrows the oxygen deligni fi cation. The white single arrows are relative to the single oxygen stage, while the two white arrows overlapping are relative to the double oxygen stage. The samples are denominated KX_OY, where X is the kappa number of the cooked pulp and Y the kappa number after oxygen deligni fi cation.
handsheets were prepared according to ISO 5269 – 1 with deionized water, to a grammage of 60 g/m 2 for the standard handsheets and a grammage of 20 g/m 2 for the tissue hand- sheets, with no pressing.
Table : Standards used for the standard and tissue handsheet characterization.
Methods
Samples
Standards
Grammage
and g/m and g/m
ISO- ISO- ISO- ISO-
- : - : - : a
Thickness and bulk Basket immersion test Capillarity rise (Klemm) Dry tensile strength
g/m g/m g/m g/m g/m
2.3 Analysis of pulp and paper properties
b
:
ISO ISO
- : - :
Table 1 and 2 present the di ff erent pulp and paper charac- terization standards. Measuring tissue properties usually depends on several factors that are often poorly controlled such as the sample size, the number of plies, among others. In the present study, the papers were produced and evaluated in the same con- ditions: lab tissue handsheets of 20 g/m 2 for the commercial fully bleached pulp and for the oxygen deligni fi edpulps.
Dry and wet tensile strength Tissue Softness analyzer (TSA)
RISE internal standard
a insteadof
b insteadof
g the test was performed with g of sample,
min
the test was performed for min.
2.3.1 Softness evaluation
The softness of the tissue handsheets was evaluated by the Tissue Softness Analyzer (TSA). TSA collects data from several sensors in the instrument, but three parameters are considered to be of most importance: softness (TS7), surface smoothness (TS750) and sheet sti ff ness (D). The equipment uses a rotating lamellar fan on the paper ’ s surface to estimate the sample ’ s softness. Both TS7 and TS750 are determined from the sound spectrum captured by microphones on either side of the sample.
Table : Standards used for the pulp characterization.
Methods
Standards
Kappa number
ISO : SCAN-C :
Water retention value (WRV)
Total fi ber charge
SCAN-CM : (Katz et al. )
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