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Chemical activation and refining of southern pine kraft fibers

a technology of southern pine and kraft fibers, applied in the field of papermaking, can solve the problems of not being able to achieve the desired modification, dramatically less refining energy, etc., and achieve the effects of enhancing freeness, reducing material deterioration, and improving the bonding of fibers within the sh

Inactive Publication Date: 2007-05-31
INT PAPER CO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention relates to a method for improving the quality of paper produced from softwood fibers by altering their morphology. This is achieved by subjecting the fibers to a metal ion-activated peroxide treatment at a pH of between about 1 and 9, followed by a refining treatment. The treated fibers have a reduced fiber length, leading to better uniformity of paper sheet structure and improved paper surface properties such as smoothness. The treatment can be applied to various processing histories of the wood, including bleaching, acid hydrolysis, or other combinations. The invention also provides a way to control the viscosity of a pulp suspension and improve tear strength and bonding of the fibers within the sheet.

Problems solved by technology

The chemical treatment of the pulp, taken alone, is not sufficient to attain the desired modification of the morphology of the fibers, however, subsequent refining or like mechanical treatment of the chemically-treated fibers to achieve a given degree of refinement of the fibers requires dramatically less refining energy, e.g., between about 30 and 50% less energy to achieve a desired end point of refinement.

Method used

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  • Chemical activation and refining of southern pine kraft fibers
  • Chemical activation and refining of southern pine kraft fibers
  • Chemical activation and refining of southern pine kraft fibers

Examples

Experimental program
Comparison scheme
Effect test

example 2

[0041] Bleached southern pine as employed in Example 1 was treated with 1% hydrogen peroxide based on pulp at pH 4, with 0.006% FE (II) as from ferrous sulfate. The treatment was carried out at the temperature of 70° C. for 1 hour. The treated pulp and control were PFI refined as in Example 1. TAPPI hand sheets were then made from these pulps.

[0042] To illustrate fiber morphology (beyond fiber length distributions) and fiber collapsibility, SEM (scanning electron microscopy) images were made of the hand sheet surface of treated vs. the control (untreated) softwood pulps, compared at 4000 Revs of PFI refining. These microphotographs are depicted in FIGS. 4 (untreated) (control) and 5 (treated) and demonstrate that the treated pine fibers are much more collapsed, or flattened, as compared to the fiber of the control. The collapsed and flattened fibers are desirable for making paper or paperboard with superior surface and printing properties. Some broken or cut fibers (fiber ends) can...

example 3

[0043] Bleached southern pine pulp was treated with 1% hydrogen peroxide catalyzed by 0.006% Fe(II) at pH 4 as in the Example 2 above. The treated pulps were PFI refined, and made into hand sheets for paper physical property evaluations. Results are shown in Table II.

TABLE IIBasisTearExtensionalWeight,Bulk,SheffieldFactorStiffness,g / m2cc / gSmoothness100*gf / g / m2lbs / in.Treated Pine Pulp730 CSF151.91.90375.6190.92960(Unrefined)556 CSF155.21.34165.3111.94780421 CSF154.41.36127.2103.45050304 CSF155.21.26129.798.15210Control Pine Pulp740 CSF162.41.91380270.93490(Unrefined)661 CSF155.61.40249.6193.64020625 CSF159.91.35185.3188.74340569 CSF158.51.31191.6167.44540443 CSF155.91.27157.8170.24340Bleached Hardwood Pulp615 CSF1661.8833352.32040584 CSF163.11.64268.687.92520544 CSF164.91.53224.41002840507 CSF161.01.40175.2112.63030462 CSF160.51.36142.2126.93010427 CSF162.81.31127.8107.83480362 CSF163.91.27389123.63320

[0044] From this table, it is noted that the treated pine, after refined to ˜560 ...

example 4

[0047] The treated pine as in Example 3 above, refined to 560 CSF, was also mixed with hardwood pulp of a range of freeness, to investigate the mixed furnish paper properties such as bulk and smoothness. The results are listed in Table III.

TABLE IIISheffield SmoothnessBulk, cc / g10% Treated Pine (560 CSF) +3231.8390% Hardwood3081.83171.21.37137.81.3320% Treated Pine (560 CSF) +3021.7580% Hardwood231.81.5182.81.43136.61.3250% Treated Pine (560 CSF) +3181.7950% Hardwood182.41.41163.41.38147.61.29

[0048]FIG. 9 plots the bulk-smoothness curve of the mixed pulp furnish (data from Table III), along with 100% pine and hardwood curves (data from Table II). It is obvious that the treated pine can be used to replace substantial amounts of hardwood pulp. The exact amount of hardwood replacement in the paper mill, however, may also be affected somewhat by the nature, type and optimization of commercial refiners.

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Abstract

A method for alteration of the morphology of cellulose fibers, particularly softwood fibers, by (a) subjecting the fibers to a metal ion-activated peroxide treatment carried out at a pH of between about 1 and about 9, preferably between 3 and 7, and (b) subjecting the treated fibers to a refining treatment thereby converts SW fibers to HW-like fibers in many respects. The metal ion-activated peroxide treatment has been noted to act on pulp cellulose and hemi-cellulose, causing oxidation and oxidative degradation of cellulose fibers. The chemical treatment of the pulp, taken alone, is not sufficient to attain the desired modification of the morphology of the fibers, however, subsequent refining or like mechanical treatment of the chemically-treated fibers to achieve a given degree of refinement of the fibers requires dramatically less refining energy to achieve a desired end point of refinement and to impart other desirable properties to the pulp. A pulp of modified SW fibers and a mixture of HW fibers and modified HW fibers are disclosed.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] Not Applicable STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT [0002] Not Applicable BACKGROUND OF THE INVENTION [0003] This invention relates to papermaking and particularly to the treatment of cellulosic material preparatory to use of the treated material to manufacture paper web material. [0004] As is well known in the art, paper is commonly formed from wood. Generally, the industry divides wood used in papermaking into two categories; namely hardwoods and softwoods. Softwood fibers (tracheids) come from needle-bearing conifer trees such as pine, spruce, alpine fir, and Douglas fir. Hardwood fibers are derived from deciduous trees of various varieties. [0005] Among the distinguishing differences between hardwood (HW) fibers and softwood (SW) fibers are(a) the length of the individual cellulosic fibers of the wood, (b) the coarseness of the fibers, and (c) the stiffness or collapsibility of the fibers. [0006] The morph...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): D21C9/00D21B1/16D21C9/10D21C9/16
CPCD21B1/16D21C9/002D21C9/1036Y10T428/298D21C3/006D21C9/004D21C9/163D21C3/02D21C9/007
Inventor TAN, ZHENGNGUYEN, XUANMAURER, KAREN
Owner INT PAPER CO
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