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Method for improving visual whiteness of blanching chemimechanical pulp and blanching chemimechanical pulp

A chemical-mechanical and whiteness bleaching technology, which is applied in chemical/chemical-mechanical pulp, pulp raw material addition process, textiles and papermaking, etc., can solve the problems that the apparent whiteness of pulp does not meet the requirements, and the cost of papermaking increases.

Active Publication Date: 2013-10-30
GOLD EAST PAPER JIANGSU
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, relying on increasing the amount of oxidant in bleached chemical mechanical pulp to improve the bleaching effect will not only lead to an increase in papermaking costs, but also cause the pulp to fail to meet the requirements for apparent brightness

Method used

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  • Method for improving visual whiteness of blanching chemimechanical pulp and blanching chemimechanical pulp
  • Method for improving visual whiteness of blanching chemimechanical pulp and blanching chemimechanical pulp

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1-4

[0019] Embodiments 1-4 add different amounts of mauve dyes to the bleached chemical mechanical pulp, specifically add the dyes to the dilution water before entering the bleaching tower (see Table 1 for the specific addition amount), and the slurry after adding the dyes is mixed with the dilution water. Spiral into the bleaching tower to produce 4 kinds of bleached chemical mechanical pulp. The high-temperature bleaching and high concentration in the bleaching tower are conducive to the adsorption of dyes on the surface of the slurry, thereby increasing the retention rate of dyes.

Embodiment 5-8

[0029] Examples 5-8 Add different amounts of purple dyes and red dyes to the bleached chemical mechanical pulp, specifically add dyes to the pulp at the entrance of the low consistency mill (see Table 2 for the specific addition amount), and respectively prepare 4 kinds Bleached chemical mechanical pulp. The high temperature generated by refining is beneficial to the retention ability of dyes on the surface of the slurry and the efficiency of dyes.

[0030] Please refer to Table 2 for the test results of brightness and apparent brightness of the four bleached chemical mechanical pulps prepared in Examples 5-8 and comparative pulps 1 and 2.

[0031] Table II

[0032]

[0033] It can be seen from Table 2 that after adding purple dye and red dye at the same time, the brightness of bleached chemical mechanical pulp pulp is greatly improved.

Embodiment 9-12

[0035] Examples 9-12 Add different amounts of purple dyes and blue-violet dyes to the bleached chemical mechanical pulp, specifically add dyes to the slurry in the dehydration tank (please refer to Table 3 for the specific addition amount), and respectively prepare 4 A bleached chemical mechanical pulp. Due to the low concentration of the slurry in the dehydration pool, it is more suitable for the addition of dyes and is conducive to uniform mixing. At the same time, it can avoid the formation of excessively dyed slurry fibers in the slurry, which will have a negative impact on the quality of papermaking.

[0036] Please refer to Table 3 for the test results of brightness and apparent brightness of the four bleached chemical mechanical pulps prepared in Examples 9-12 and comparative pulps 1 and 2.

[0037] Table three

[0038]

[0039] It can be seen from Table 3 that after adding the purple dye and the blue-violet dye at the same time, the brightness of the bleached chemi...

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PUM

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Abstract

The invention discloses a method for improving visual whiteness of blanching chemimechanical pulp. The method comprises the following step of: adding 5-120 ppm of water-soluble dyestuff in a blanch process of a pulp line, a blanch full stuff process or a full stuff tower, wherein the dyestuff is amaranth dyestuff, blue dyestuff, purple dyestuff, bluish violet dyestuff, red dyestuff, a mixture of purple dyestuff and red dyestuff, a mixture of the amaranth dyestuff and the red dyestuff, the mixture of the amaranth dyestuff and the bluish violet dyestuff, or the mixture of the purple dyestuff and the blue dyestuff. The method provided by the invention has the advantages that through the dyestuff added in the blanching chemimechanical pulp, the yellow phase value is reduced, the a * value of pulp is also increased, a b* value is reduced, the whiteness of the full stuff is improved, in addition, the additive amount of a blanching chemical in the stuff is also reduced, and the cost is effectively reduced. The invention also provides the blanching chemimechanical pulp prepared by the method.

Description

technical field [0001] The invention relates to a method for improving the apparent brightness of bleached chemical mechanical pulp and the bleached chemical mechanical pulp produced by the method. Background technique [0002] In the field of papermaking, oxidizing agents are usually used to bleach chemical mechanical pulp (PRC-APMP, APMP, BCTMP) to improve the whiteness and apparent whiteness of the pulp. The oxidizing agent used can be hydrogen peroxide (H 2 o 2 ), formamidine sulfinic acid (FAS), hydrosulfite, etc. However, relying on increasing the addition of oxidants in bleached chemical mechanical pulp to improve the bleaching effect will not only increase the cost of papermaking, but also cause the pulp's apparent brightness to fail to meet the requirements. [0003] There is a close relationship between whiteness and visual whiteness (apparent whiteness), but there are differences between the two. The whiteness is obtained by testing the blue light in the visib...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): D21H21/28D21H11/02D21H23/14
Inventor 董郑伟王仁荣韦丹
Owner GOLD EAST PAPER JIANGSU
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