# Patent

## Title
Method for removing ink from paper

## Abstract

A method for removing ink from printed paper comprising: (a) pulping printed paper at least 25 wt % of which is old newsprint at a consistency of at least about 3% to obtain a pulp slurry; (b) treating the pulp slurry with an ink removing system, which system comprises: (i) a combination of lipase and at least one second enzyme chosen from amylase, xylanase or cellulase, and (ii) a non-ionic surfactant, in amounts effective to release ink from said pulp slurry, wherein the lipase is present in an amount of at least about 0.001 wt % based on the dry content of the pulp slurry and the ratio of the at least one second enzyme:lipase is at least about 1.2:1; and (c) separating the released ink from the pulp slurry, wherein the treating step is carried out prior to a deinking flotation stage.

## Background
This application is a national stage filing under 35 U.S.C. §371 of PCT/US2011/024501, filed Aug. 18, 2011, which claims priority to U.S. Provisional Patent Application No. 61/303,828, filed on Feb. 12, 2010, and European Patent Application No. 10164835.0, filed Mar. 6, 2010, the contents of which are incorporated herein by reference in their entirety.


FIELD OF THE INVENTION
The field of the invention relates to methods for deinking and decolorizing printed paper. More particularly, it relates to methods for removing ink from a paper pulp containing old newsprint.
BACKGROUND OF THE INVENTION
The paper industry has been practicing wastepaper recycling to regenerate usable cellulosic fiber for paper making for many decades. In these processes, ink is removed from the wastepaper pulp using a suitable deinking composition. The deinking process produces a new paper or paperboard product out of materials that might otherwise have ended up in a landfill.
Because of increasing public demand, the use of recycled paper has steadily increased. To recover the fibers used for papermaking from wastepaper, a waste paper deinking operation must generally be carried out to remove the inks used in printing, and thus create suitable characteristics for re-use. Increasing amounts of wastepaper, e.g. old newspapers (ONP) and waste magazines (WM), are becoming available with increased participation of end consumers in recycling.
In the course of conventional paper reclamation, deinking procedures include steps for converting the wastepaper to pulp and contacting the pulp with an alkaline aqueous deinking medium containing a chemical deinking agent. The mechanical action and the alkalinity of the aqueous medium cause the partial removal of ink from the pulp fiber. The deinking agent completes this removal and produces an aqueous suspension and/or dispersion of the ink particles. The resulting mixture is subsequently treated to separate the suspended/dispersed ink from the pulp. This separation may be by flotation and/or washing techniques known in the art.
Conventional deinking chemicals comprise a complex mixture of chemicals, e.g. sodium hydroxide, sodium silicate, chelating agents, hydrogen peroxide, surfactants, dispersants, collector chemicals and agglomeration chemicals. In general, it is standard in deinking to include a significant amount of alkaline material, since it is believed that the alkaline material is needed for sufficient saponification and hydrolysis of the ink resins. In addition, mention is made of the fiber swelling by the caustic being partially responsible for the detachment of ink particles from the fiber surface. Typically, the pH during such a deinking process is from about 9.5 to about 11. Exposing the cellulosic and lignocellulosic fibers to this degree of alkalinity tends to cause yellowing of the fibers and, therefore, it is generally necessary to add an oxidative or reductive bleaching agent, such as peroxide or sodium hydrosulfite. The reductive bleaching step is commonly employed at the end of the deinking process while hydrogen peroxide is added at the pulper. In some deinking operations hydrogen peroxide will be added later in the process.
Furthermore, the alkaline method causes irreversible changes to the pulp fibers, and hence represents a cost to the facility in addition to just the cost of using the chemical. Using caustic will also solubilize papermaking additives and coatings that will lead to additional runnability problems due to deposits at the paper machine.
Thus, there is a need for a deinking process that avoids these shortcomings, which is safe and which is economically and environmentally desirable.
It has been found by the present inventors that treatment of a wastepaper containing pulp with an ink removing system in accordance with the present invention fulfills the above-mentioned requirements to such a deinking process.
SUMMARY OF THE INVENTION
The present invention is directed to a method for removing ink from printed paper. In one embodiment, the invention relates to removing ink from a pulp containing old news print (ONP) and maintaining or increasing brightness of the deinked pulp in a neutral deinking process.
In a first aspect, the invention is directed to a method for removing ink from printed paper, which comprises: (a) pulping printed paper at least 25 wt % of which is old newsprint at a consistency of at least about 3% to obtain a pulp slurry; (b) treating the pulp slurry with an ink removing system, which system comprises: (i) a combination of lipase and at least one second enzyme chosen from amylase, xylanase or cellulase, and (ii) a non-ionic surfactant, in amounts effective to release ink from said pulp slurry, wherein the lipase is present in an amount of at least about 0.001 wt % based on the dry content of the pulp slurry and the ratio of the at least one second enzyme:lipase is at least about 1.2:1; and (c) separating the released ink from the pulp slurry in a deinking step (e.g., a deinking flotation stage) to provide a deinked pulp slurry, wherein the treating step is carried out prior to the deinking step.
In one embodiment of the invention, the enzyme combination is a combination of lipase and xylanase. The ratio of xylanase:lipase can be at least about 1.5:1. In embodiments of the invention, the ratio of xylanase:lipase can be chosen from a ratio in the range of about 1.5:1 to about 5:1; about 1.5:1 to about 4:1; about 1.5:1 to about 3:1; about 1.5:1 to about 2.5:1; about 2:1 to about 4:1; or about 2:1 to about 3:1. In additional embodiments the ratio of xylanase:lipase can be chosen from about 2:1, 2.5:1 or 3:1.
In an embodiment of the invention, the non-ionic surfactant can be chosen from fatty acid alkoxylates, fatty alcohol alkoxylates or mixtures thereof. The non-ionic surfactant can be chosen from fatty alcohol ethyoxylates (FAEO), propoxylates (FAPO) and combinations thereof (FAEPO).
In embodiments of the invention, the ratio of (i):(ii) present in the ink removing system can be chosen from a ratio in the range of about 1:1 to about 1:10; about 1:1 to about 1:5; or about 1:2 to about 1:4.
In another aspect of the invention, the above ink removing system can further comprise (iii) a soap. In another aspect, the ink removing system can further comprise (iv) an alkaline reagent. In yet another aspect, the ink removing system can further comprise (iii) a soap and (iv) an alkaline reagent.
In one embodiment, the consistency can be in the range of about 3 to about 30%. In additional embodiments, the consistency can be chosen from a value in the range of about 10% to about 17%, or about 18 to about 23%.
In an embodiment of the invention, the printed paper comprises at least about 40 wt % ONP. In another embodiment, the printed paper comprises at least about 50 wt % ONP. In other embodiments, the printed paper comprises ONP in an amount chosen from within the range of from about 40 to about 95 wt %, about 45 to about 90 wt %, or about 50 to about 80 wt %. In yet another embodiment of the invention, the printed paper further comprises old magazine print (OMG).
In one embodiment, where the ink removing system comprises (iii) a soap and (iv) an alkaline reagent, the combination of enzymes (i) can be a combination of lipase and xylanase. In such an embodiment, the ratio of xylanase:lipase can be as discussed above.
In one embodiment of the invention, the soap can be fatty acid soap. In another embodiment, the fatty acid soap can be derived from tallow. In yet another embodiment, the fatty acid soap can be derived from plant oils.
In one embodiment of the invention, the alkaline reagent is sodium silicate. In one embodiment, the combination of enzymes (i) is a combination of lipase and xylanase; the non-ionic surfactant (ii) is chosen from fatty alcohol ethoxylates (FAEO), propoxylates (FAPO) and combinations thereof (FAEPO); the soap (iii) is a tallow fatty acid soap; and the alkaline reagent (iv) is sodium silicate. In such an embodiment, the ratio of xylanase:lipase and the ratio of (i):(ii) can be as discussed above.
In one aspect of the invention, components (i) and (ii) are premixed to form an enzyme composition (v) and then adding (v) to the pulp slurry as a component of the ink removing system. In one embodiment, the enzyme composition (v) is added to the pulp slurry in an amount in the range of about 0.04 to about 0.5 wt %, the soap (iii) is added to the pulp slurry in an amount in the range of about 0.1 to about 1 wt %, and the alkaline reagent (iv) is added to the pulp slurry in an amount in the range of about 0.5 to about 2 wt %, all based on the solid content of the slurry.
In one embodiment of the invention, the pH of the slurry is maintained in the range of about 6 to about 11. The preferred range is 6.7 to 9.5, the more preferred range is 7 to 9 and the most preferred range is 7.5 to 8.8.
In one embodiment of the invention, the slurry is substantially free of sodium sulfite. In another embodiment the slurry is substantially free of sodium hydroxide or, if added to the slurry, the sodium hydroxide is added in an amount less than about 0.15 wt %, based on the weight of the slurry. In yet another embodiment, the slurry is substantially free of hydrogen peroxide. In yet another embodiment, two or all of these requirements (of being free of a specified material) are met.
Additional objects, advantages and novel features will be apparent to those skilled in the art upon examination of the description that follows.



BRIEF DESCRIPTIONS OF THE DRAWINGS
FIG. 1 is a graph showing the effect of enzymes and sodium sulfite on brightness (pulper) for Example 1 deinking systems.
FIG. 2 is a graph showing the effect of enzymes and sodium sulfite on brightness (Flot and Hyper) for Example 1 deinking systems.
FIG. 3 is a graph showing the effect of enzymes and sodium sulfite on brightness difference (vs. conventional) for Example 1 deinking systems.
FIG. 4 is a graph showing the effect of enzymes and sodium sulfite on brightness (pulper) for Example 2 deinking systems.
FIG. 5 is a graph showing the effect of enzymes and sodium sulfite on brightness (Flot and Hyper) for Example 2 deinking systems.
FIG. 6 is a graph showing the effect of enzymes and sodium sulfite on brightness difference (vs. conventional) for Example 2 deinking systems.
FIG. 7 is a graph showing the effect of enzymes and sodium sulfite on brightness (pulper) for Example 3 deinking systems.
FIG. 8 is a graph showing the effect of enzymes and sodium sulfite on brightness (Flot and Hyper) for Example 3 deinking systems.
FIG. 9 is a graph showing the effect of enzymes and sodium sulfite on brightness difference (vs. conventional) for Example 3 deinking systems.
FIG. 10 is a graph showing the effect of enzymes and sodium sulfite on brightness (pulper) for Example 4 deinking systems.
FIG. 11 is a graph showing the effect of enzymes and sodium sulfite on brightness (Flot and Hyper) for Example 4 deinking systems.
FIG. 12 is a graph showing the effect of enzymes and sodium sulfite on brightness difference (vs. conventional) for Example 4 deinking systems.
FIG. 13 is a graph showing the effect of enzymes and sodium sulfite on brightness (pulper) for Example 5 deinking systems.
FIG. 14 is a graph showing the effect of enzymes and sodium sulfite on brightness (Flot and Hyper) for Example 5 deinking systems.
FIG. 15 is a graph showing the effect of enzymes and sodium sulfite on brightness difference (vs. conventional) for Example 5 deinking systems.
FIG. 16 is a graph showing the effect of paper source, enzymes and sodium sulfite on brightness (pulper) for Example 6 deinking systems.
FIG. 17 is a graph showing the effect of paper source, enzymes and sodium sulfite on brightness (Flot and Hyper) for Example 6 deinking systems.
FIG. 18 is a graph showing the effect of paper source, enzymes and sodium sulfite on brightness difference (vs. conventional) for Example 6 deinking systems.
FIG. 19 is a graph showing the effect of paper source, enzymes and sodium sulfite on brightness (pulper) for Example 7 deinking systems.
FIG. 20 is a graph showing the effect of paper source, enzymes and sodium sulfite on brightness (Flot and Hyper) for Example 7 deinking systems.
FIG. 21 is a graph showing the effect of paper source, enzymes and sodium sulfite on brightness difference (vs. conventional) for Example 7 deinking systems.
FIG. 22 is a graph showing the effect of enzymes and sodium sulfite on brightness (pulper) for Example 8 deinking systems.
FIG. 23 is a graph showing the effect of enzymes and sodium sulfite on brightness (Flot and Hyper) for Example 8 deinking systems.
FIG. 24 is a graph showing the effect of enzymes and sodium sulfite on brightness difference (vs. conventional) for Example 8 deinking systems.
FIG. 25 is a graph showing the effect of enzymes and sodium sulfite on brightness (pulper) for Example 9 deinking systems.
FIG. 26 is a graph showing the effect of enzymes and sodium sulfite on brightness (Flot and Hyper) for Example 9 deinking systems.
FIG. 27 is a graph showing the effect of paper source, enzymes and sodium sulfite on brightness (pulper) for Example 10 deinking systems.
FIG. 28 is a graph showing the effect of paper source, enzymes and sodium sulfite on brightness (Flot and Hyper) for Example 10 deinking systems.
FIG. 29 is a graph showing the effect of paper source, enzymes and sodium sulfite on brightness difference (vs. conventional) for Example 10 deinking systems.
FIG. 30 is a graph showing the effect of paper source, enzymes and sodium sulfite on brightness (pulper) for Example 11 deinking systems.
FIG. 31 is a graph showing the effect of paper source, enzymes and sodium sulfite on brightness (Flot and Hyper) for Example 11 deinking systems.
FIG. 32 is a graph showing the effect of paper source, enzymes and sodium sulfite on brightness difference (vs. conventional) for Example 11 deinking systems.
FIG. 33 is a graph showing the effect of enzymes and sodium sulfite on brightness (pulper) for Example 12 deinking systems.
FIG. 34 is a graph showing the effect of enzymes and sodium sulfite on brightness (Flot and Hyper) for Example 12 deinking systems.
FIG. 35 is a graph showing the effect of enzymes and sodium sulfite on brightness difference (vs. conventional) for Example 12 deinking systems.
FIG. 36 is a graph showing the effect of enzymes, sodium hydroxide and sodium sulfite on brightness (pulper) for Example 13 deinking systems.
FIG. 37 is a graph showing the effect of enzymes, sodium hydroxide and sodium sulfite on brightness (Flot and Hyper) for Example 13 deinking systems.
FIG. 38 is a graph showing the effect of enzymes, sodium hydroxide and sodium sulfite on brightness difference (vs. conventional) for Example 13 deinking systems.
FIG. 39 is a graph showing the effect of enzymes and sodium sulfite on brightness (pulper) for Example 14 deinking systems.
FIG. 40 is a graph showing the effect of enzymes and sodium sulfite on brightness (Flot and Hyper) for Example 14 deinking systems.
FIG. 41 is a graph showing the effect of enzymes and sodium sulfite on brightness difference (vs. conventional) for Example 14 deinking systems.
FIG. 42 is a graph showing the effect of enzymes, sodium hydroxide and sodium sulfite on brightness (pulper) for Example 15 deinking systems.
FIG. 43 is a graph showing the effect of enzymes, sodium hydroxide and sodium sulfite on brightness (Flot and Hyper) for Example 15 deinking systems.
FIG. 44 is a graph showing the effect of enzymes, sodium hydroxide and sodium sulfite on brightness difference (vs. conventional) for Example 15 deinking systems.



DETAILED DESCRIPTION OF THE INVENTION
The present invention is directed to a method for removing ink from printed paper. In one embodiment, the invention relates to removing ink from a pulp containing old news print (ONP) and maintaining or increasing brightness of the deinked pulp in a neutral deinking process.
In one aspect the invention is directed to an ink removing system, which system comprises: (i) a combination of lipase and at least one second enzyme chosen from amylase, xylanase or cellulase, and (ii) a non-ionic surfactant, in amounts effective to release ink from said pulp slurry, wherein the lipase is present in an amount of at least about 0.001 wt % based on the dry content of the pulp slurry and the ratio of the at least one second enzyme:lipase is at least about 1.2:1.
In one embodiment of the invention, the enzyme combination is a combination of lipase and xylanase. The ratio of xylanase:lipase can be at least about 1.5:1. In embodiments of the invention, the ratio of xylanase:lipase can be chosen from a ratio in the range of about 1.5:1 to about 5:1; about 1.5:1 to about 4:1; about 1.5:1 to about 3:1; about 1.5:1 to about 2.5:1; about 2:1 to about 4:1; or about 2:1 to about 3:1. In additional embodiments the ratio of xylanase:lipase can be chosen from about 2:1, 2.5:1 or 3:1.
In embodiments of the method for removing ink, the total amount of enzyme added to the pulp slurry in the ink removal system is less than 0.5 lbs (0.23 kg), or 0.45 lbs (0.2 kg), or 0.4 lbs (0.18 kg), or 0.3 lbs (0.14 kg) per ton (2000 lbs) of dry pulp.
In embodiments of the method for removing ink, the components of the ink removing system are present in an amount to achieve an ink removal efficiency of at least about 50%, or at least about 60%, or at least about 70%, or at least about 80% in the subsequent deinking flotation stage. Ink removal efficiency means the percentage of ink removed based on the original amount of ink contained in the printed paper pulp prior to treating with the ink removal system and subjecting it to a deinking step to provide a deinked pulp. For example, 50% ink removal efficiency means the deinked pulp has 50% less ink than the starting printed paper pulp. In embodiments of the invention, the pulp slurry after the deinking step (e.g., deinking flotation stage) has a substantially reduced amount of ink, including the printing ink resins or oils of the type typically contained in printing ink systems.
In embodiments of the invention, the deinked pulp contains less than 0.2 wt % or is substantially free of vegetable oils and mineral oils found in printing inks. In an embodiment of the method for removing ink, no vegetable or mineral oil is added to the pulp slurry.
Examples of nonionic surfactants include a higher aliphatic alcohol alkoxylate, aliphatic acid alkoxylate, higher aromatic alcohol alkoxylate, fatty acid amide of alkanolamine, fatty acid amide alkoxylate, propylene glycol alkoxylate, block or random copolymer of ethylene and propylene oxide, or higher alcohol polyethylene polypropylene block or random adducts.
In an embodiment of the invention, the non-ionic surfactant can be chosen from fatty acid alkoxylates, fatty alcohol alkoxylates or mixtures thereof. The non-ionic surfactant can be chosen from fatty alcohol ethyoxylates (FAEO), propoxylates (FAPO) and combinations thereof (FAEPO). In an embodiment of the invention, the non-ionic surfactant is chosen or incorporated in a system to provide a low foaming deinking system. The non-ionic surfactant itself, or composition containing the surfactant, can be low foaming. Examples of commercially available surfactant products that are useful in the present invention include Eka RF 4000 and 4200 series deinking products available from Eka Chemicals, and in particular Eka RF 4031 and Eka RF 4291. In one embodiment, the Eka RF 4291 deinking product is preferred to be included.
In one aspect of the invention, the ink removing system can further comprise (iii) a soap. In another aspect, the ink removing system can further comprise (iv) an alkaline reagent. In yet another aspect, the ink removing system can further comprise (iii) a soap and (iv) an alkaline reagent.
The soap can be fatty acid soap. The fatty acid soap can be derived from tallow or can be derived from plant oils.
In one embodiment of the invention, the alkaline reagent is sodium silicate.
EXAMPLES
The following examples were conducted to evaluate the performance of deinking systems in a neutral deinking process:

    
    
        1. Flot studies using a ratio of 70% old newsprint (ONP) and 30% Old Magazine (OMG) were conducted using a mixture of the Wall Street Journal and the Los Angles Times. The example represents an average of tests that have similar amounts of rejects and hyperwash ERIC values. The test conditions were selected based on the assumption that the character of the ink changes with age so having similar hyperwash ERIC values means that the results are for paper with comparable aging effects.
        2. Flot studies using just the Wall Street Journal were conducted based on preliminary tests showing that the different newspapers were impacting the amount of rejects.
        3. Flot studies using just the Globe and Mail from Canada were conducted.
        4. The results for a mill scale trial conducted in Canada.
    
    


Typical equipment, furnish and conditions used for examples 1-15 were as follows:
Equipment and Furnish







TABLE 1





Pulper Components used in Examples.


















Pulper
Kitchen Aid Mixer



Flot Cell
Stainless Steel FRED Cell




(Flotation with Radial Ejection




Deinking Cell)



Furnish Mix
70/30



ONP/OMG



Amount
  50 g air weight dry



Old Newsprint



Wall Street Journal
17.5 g



(WSJ)



LA Times (LAT)
17.5 g



Old Magazine



People
  5 g



Shape
  5 g



Bazaar
  5 g



Old Newsprint Canada



Globe & Mail
  32 g










Conditions:








TABLE 2





Pulping Conditions for Examples.
















Pulping Time
10 min


Pulping
45° C.


Temperature
(Water baths were run 5° C. higher)


Pulping %
12%


Consistency Kitchen


Aid


Pre-pulping soak
0 min


Pulping Hardness
Use tap water


Hold Time after
10 min


pulping


Flotation Time
5-8 min


Flotation %
1%


Consistency


Weight of Stock
3750-4200 g


Added


Hardness (added at
9 ml of 10% CaCl2


flot)
If flot feed hardness is not at desired level after


Target hardness
addition of the 9 ml - additional CaCl2 added until


around 180 ppm
desired ppm


Samples
Pulper, Flot Accepts, Hyperwash Flot Accept


Rejects
Volume, Weight, Ash


Pump Speed
60


Air
15-20 SCHF









Pulper Chemistry and Deinking Dosage:








TABLE 3







Pulper and deinking chemistry for Examples.









% on Fiber











Conventional Chemistry:












NaOH (10%)
   1%




Na Silicate (NaSil)
  1.5%




H2O2
   1%



Deinking Agents
Eka RF 4031
  0.5%




Eka RF 4291
 0.06%







Neutral Chemistry












Sodium Sulfite (NaSul)
  1.5%




NaSil
  1.5%



Deinking Agents
Eka RF 4031
  0.5%




Eka RF 4291
 0.06%







Neutral Chemistry + Enzymes with No Sulfite












NaSil
  1.5%



Deinking Agents
Eka RF 4031
  0.5%




Eka RF 4291
 0.06%




Eka RF 4031-E6634:
0.5225%




95.7% RF 4031, 2.9%




Xylanase, 1.4% Lipase




Eka RF 4291-E6634:
0.0825%




72.7% RF 4291, 18.2%




Xylanase, 9.1% Lipase



Enzymes
(treated as 100% active)




Xylanase
Varied




Lipase
Varied




E6634: 66% xylanase,
Varied




34% lipase




E5050: 50% xylanase,
Varied




50% lipase










In each of the Examples, the tests were run in random order to prevent run order errors, but are listed in the tables out of sequence to group the tests according to the conditions used, e.g., cell level and enzymes used, to make analysis easier. In some Examples, test numbers have been omitted from the tables where duplicate tests were run or where a unique chemistry was used, e.g., another component was added, that makes the tests not relevant or not comparable to the present invention. In the case of duplicate tests, the results listed in the tables are an average of the results for the duplicate tests.
Regarding pulp liquor pH, while it is not always possible or easy to measure the pH of the combined pulping chemicals and dilution water in a particular mill setting in real time, it can be measured in a lab setting. Accordingly, in the following examples the measured pH of the combined chemicals and the dilution water is referred to as the “Pulp Liquor pH”, which is helpful in seeing how changes in alkaline reagents addition impact of pH.
Example 1
The pulping recipes used in Example 1 (Tests 1-16) are listed below in Table 4. The specific pulping components and conditions were: 17.5 grams each of WSJ and LAT, flotation time of 8 min, and air rate of 20 SCHF. The pH operating ranges used for Example 1 are listed below in Table 5.







TABLE 4







Pulping recipes for tests 1-16 (Example 1).

















Cell






Pulp



Test
Level,

Deinking

Xylanase
Lipase

Liquor


#
grams
Pulper
Agents
Sulfite
%
%
Ratio
pH
FF pH



















1
4200
Conventional
Eka RF 4291 +



NA
10.9
8.8





Eka RF 4031


2
4200
Sodium Sulfite
Eka RF 4291 +
Yes


NA
9.4
7.5





Eka RF 4031


5
4200
NaSul + Xylanase
Eka RF 4291 +
Yes
0.03
0
NA

7.5





Eka RF 4031


4
4200
NaSul + Xylanase
Eka RF 4291 +
Yes
0.06
0
NA
9.5
7.4





Eka RF 4031


6
3750
NaSul + Xylanase
Eka RF 4291 +
Yes
0.03
0
NA
9.6
7.5





Eka RF 4031


3
3750
NaSul + Xylanase
Eka RF 4291 +
Yes
0.06
0
NA
9.4
7.4





Eka RF 4031


7
3750
NaSul + Blend
Eka RF 4291 +
Yes
0.03
0.03
50/50
9.6
7.5





Eka RF 4031


8
3750
NaSul + Blend
Eka RF 4291 +
Yes
0.015
0.03
34/66
9.6
7.4





Eka RF 4031


10
3750
Lipase
Eka RF 4291 +
No
0
0.015
NA
9.4
7.4





Eka RF 4031


9
3750
Lipase
Eka RF 4291 +
No
0
0.03
NA
9.4
7.5





Eka RF 4031


14
3750
NaSul + Lipase
Eka RF 4291 +
Yes
0
0.015
NA
9.6
7.4





Eka RF 4031


13
3750
NaSul + Lipase
Eka RF 4291 +
Yes
0
0.03
NA
9.6
7.5





Eka RF 4031


12
4200
Lipase
Eka RF 4291 +
No
0
0.003
NA
9.4
7.3





Eka RF 4031


11
4200
Lipase
Eka RF 4291 +
No
0
0.0075
NA
9.5
7.5





Eka RF 4031


16
4200
NaSul + Lipase
Eka RF 4291 +
Yes
0
0.003
NA
9.6
7.6





Eka RF 4031


15
4200
NaSul + Lipase
Eka RF 4291 +
Yes
0
0.0075
NA
9.6
7.6





Eka RF 4031
















TABLE 5







pH ranges for Example 1 for neutral deinking.











Pulping Flot



Pulping Liquor
Feed















Max pH
9.6
7.6



Min pH
9.4
7.3










The deinking performance of the various test recipes were evaluated and the results are shown below in Table 6.







TABLE 6







Deinking Results for tests 1-16 (Example 1).


















Wet






Brightness
Brightness
Removal


Test
Reject
ERIC
ERIC
ERIC
Brightness
Brightness
Brightness
Difference
Difference
Efficiency


#
Wt.
Pulper
Flot
Hyper
Pulper
Flot
Hyper
vs. Conv
vs. Sulfite
at Flot




















1
297
992
261
171
42.98
54.72
57.34

−1.5
74


2
283
1011
254
112
43.13
56.25
57.76
1.5

75


5
35
1026
221
143
43.65
57.00
56.26
2.3
0.7
78


4
452
1040
224
125
43.20
56.82
57.23
2.1
0.6
78


6
92
1037
287
114
43.35
55.44
57.08
0.7
−0.8
72


3
87
988
233
126
43.70
56.92
56.38
2.2
0.7
76


7
325
1006
155
175
44.50
59.20
56.55
4.5
2.9
85


8
341
1020
154
164
44.70
59.10
56.94
4.4
2.8
85


10
147
955
210
136
44.81
56.91
56.56
2.2
0.7
78


9
192
993
198
119
44.31
57.31
56.36
2.6
1.1
80


14
217
1112
221
151
43.22
56.89
56.75
2.2
0.6
80


13
447
1154
161
143
43.29
58.99
56.69
4.3
2.7
86


12
474
979
233
128
44.33
56.49
56.52
1.8
0.2
76


11
541
1032
222
130
43.13
56.55
56.38
1.8
0.3
78


16
593
1098
191
141
43.04
57.59
56.50
2.9
1.3
83


15
632
1066
183
127
43.38
57.66
56.89
2.9
1.4
83









In addition to the results in Table 6, the following was observed: tests 3, 5 and 6 had less foam with less rejects generated; tests 7 and 8 (with enzyme blends) gave the best ink removal; tests 11, 12, 15 and 16 had too much wet rejects; and test 13 showed good ink removal but too much rejects. For this Example a reject amount over about 350 g was considered too high a yield loss.
The results of the deinking tests for Example 1 are shown graphically in FIGS. 1-3. A review of these figures shows that blending the lipase and xylanase at ratios of 50/50 or 66/34 gave the best deinking performance with a reasonable level of rejects. Lipase and xylanase added with a recipe that included sodium sulfite also performed better than conventional or sulfite based neutral deinking.
Example 2
The pulping recipes used in Example 2 (Tests 1-16) are listed below in Table 7. The specific pulping components and conditions were: 17.5 grams each of WSJ and LAT, flotation time of 8 min, and air rate of 20 SCHF. The pH operating ranges for Example 2 are listed below in Table 7.







TABLE 7







Pulping recipes for tests 1-16 (Example 2).

















Cell






Pulp



Test
Level,

Deinking

Xylanase
Lipase

Liquor


#
grams
Pulper
Agents
Sulfite
%
%
Ratio
pH
FF pH



















1
4200
Conventional
Eka RF4291,
No
0
0
NA
11.25
8.95





Eka RF4031


2
4200
Sodium Sulfite
Eka RF4291,
Yes
0
0
NA
9.56
7.71





Eka RF 4031


4
3750
NaSul + Blend
Eka RF4291,
Yes
0.0015
0.03
 5/95
9.60
7.56





Eka RF4031


3
3750
NaSul + Blend
Eka RF4291,
Yes
0.03
0.03
50/50
9.61
7.55





Eka RF4031


7
4200
NaSul + Blend
Eka RF4291,
Yes
0.015
0.015
50/50
9.60
7.62





Eka RF4031


8
4200
NaSul + Blend
Eka RF4291,
Yes
0.03
0.015
66/34
9.63
7.57





Eka RF4031


6
4200
NaSul + Blend
Eka RF4291,
Yes
0.0015
0.03
 5/95
9.60
7.55





Eka RF4031


5
4200
NaSul + Blend
Eka RF4291,
Yes
0.03
0.03
50/50
9.57
7.53





Eka RF4031


13
4200
Blend
Eka RF4291,
No
0.015
0.015
50/50
9.51
7.26





Eka RF4031


14
4200
Blend
Eka RF4291,
No
0.03
0.015
66/34
9.48
7.25





Eka RF4031


16
4200
Blend
Eka RF4291,
No
0.075
0.015
80/20
9.47
7.38





Eka RF4031


12
4200
Blend
Eka RF4291,
No
0.0015
0.03
 5/95
9.45
7.44





Eka RF4031


11
4200
Blend
Eka RF4291,
No
0.003
0.03
50/50
9.44
7.52





Eka RF4031


15
4200
Blend
Eka RF4291,
No
0.015
0.075
20/80
9.34
7.43





Eka RF4031
















TABLE 8







pH ranges for Example 2 for neutral deinking.











Pulping Flot



Pulping Liquor
Feed















Max pH
9.6
7.7



Min pH
9.3
7.3










The deinking performance of the various test recipes were evaluated and the results are shown below in Table 9.







TABLE 9







Deinking Results for tests 1-16 (Example 2).


















Wet






Brightness
Brightness
Removal


Test
Reject
ERIC
ERIC
ERIC
Brightness
Brightness
Brightness
Difference
Difference
Efficiency


#
Wt.
Pulper
Flot
Hyper
Pulper
Flot
Hyper
vs. Conv
vs. Sulfite
at Flot




















1
318
997
339
133
45.5
53.7
56.8
NA
0.42
66.0


2
325
1054
409
152
44.6
53.3
53.8
−0.42
NA
61.2


4
349
1030
191
150
45.8
56.9
54.9
3.20
3.61
81.5


3
404
973
177
147
46.4
57.4
54.4
3.71
4.13
81.8


7
679
1005
176
164
46.5
57.8
52.9
4.06
4.47
82.5


8
602
1089
186
135
45.7
58.0
53.7
4.31
4.73
82.9


6
680
1030
196
175
46.0
57.7
54.3
3.94
4.35
81.0


5
715
1079
177
169
45.9
57.9
52.7
4.12
4.53
83.6


13
598
934
194
114
46.2
56.7
52.1
2.95
3.36
79.2


14
634
1010
166
130
46.7
57.7
53.5
4.01
4.42
83.6


16
550
962
204
115
46.6
56.5
53.6
2.79
3.20
78.8


12
521
956
206
126
46.0
56.5
54.9
2.75
3.16
78.5


11
566
962
203
125
46.3
56.5
53.8
2.74
3.15
78.9


15
890
967
166
115
45.9
56.9
52.0
3.16
3.57
82.8









In addition to the results in Table 9, the following was observed: tests 5-8 and 11-16 had too much rejects. For this Example a reject amount over about 400 g was considered too high a yield loss.
The results of the deinking tests for Example 2 are shown graphically in FIG. 3-6. A review of these figures shows that a blend of lipase and xylanase at either a ratio of 95/5 or 50/50 and a cell level of 3750 g performed better than conventional or sulfite based neutral deinking. Much of the study was conducted at a level of 4200 g which rejected too much material. Removing sodium sulfite but keeping the enzymes reduced reject volume and improved ink detachment. Dosages of lipase of 0.15% and 0.03% gave about the same level of rejects.
Example 3
The pulping recipes used in Example 3 (Tests 1-17) are listed below in Table 10. The specific pulping components and conditions were: 17.5 grams each of WSJ and LAT, flotation time of 8 min, and air rate of 20 SCHF. The pH operating ranges for Example 3 are listed below in Table 11.







TABLE 10







Pulping recipes for tests 1-17 (Example 3).

















Cell






Pulp



Test
Level,

Deinking

Xylanase
Lipase

Liquor


#
grams
Pulper
Agents
Sulfite
%
%
Ratio
pH
FF pH



















1
4200
Conventional
Eka RF4291,




11.22
9.17





Eka RF4031


2
4200
Sodium Sulfite
Eka RF4291,
Yes



9.58
7.79





Eka RF 4031


4
3750
NaSul + Blend
Eka RF4291,
Yes
0.015
0.015
50/50
9.61
7.76





Eka RF4031


3
3750
NaSul + Blend
Eka RF4291,
Yes
0.015
0.03
34/66
9.61
7.80





Eka RF4031


17
4200
Blend
Eka RF4291,

0.015
0.0075
66/34
9.43
7.45





Eka RF4031


15
4200
NaSul + Blend
Eka RF4291,
Yes
0.0075
0.0075
50/50
9.44
6.84





Eka RF4031


10
4200
NaSul + Blend
Eka RF4291,
Yes
0.015
0.015
50/50
9.60
7.50





Eka RF4031


11
4200
NaSul + Blend
Eka RF4291,
Yes
0.03
0.03
50/50
9.58
7.51





Eka RF4031


16
4200
Blend
Eka RF4291,

0.0075
0.0075
50/50
9.58
7.63





Eka RF4031


14
4200
Blend
Eka RF4291,

0.015
0.0075
66/34
9.42
7.00





Eka RF4031


13
4200
Blend
Eka RF4291,

0.0075
0.015
34/66
9.38
7.20





Eka RF4031


12
4200
Blend
Eka RF4291,

0.015
0.015
50/50
9.41
6.98





Eka RF4031


5
4200
NaSul w H2O2
Eka RF4291,
Yes



9.48
7.74





Eka RF4031


6
4200
NaSul w H2O2
Eka RF4291,
Yes



9.50
7.68





Eka RF4031


7
4200
H2O2
Eka RF4291,




9.23
7.10





Eka RF4031


8
4200
H2O2
Eka RF4291,




9.29
6.94





Eka RF 4031
















TABLE 11







pH ranges for Example 3 for neutral deinking.











Pulping Flot



Pulping Liquor
Feed















Max pH
9.6
7.8



Min pH
9.2
6.8










The deinking performance of the various test recipes were evaluated and the results are shown below in Table 12.







TABLE 12







Deinking Results for tests 1-17 (Example 3).


















Wet






Brightness
Brightness
Removal


Test
Reject
ERIC
ERIC
ERIC
Brightness
Brightness
Brightness
Difference
Difference
Efficiency


#
Wt.
Pulper
Flot
Hyper
Pulper
Flot
Hyper
vs. Conv
vs. Sulfite
at Flot




















1
470
1057
298
113
43.4
54.0
57.3

−2.6
71.9


2
542
1155
244
132
43.5
56.6
57.3
2.6

78.9


4
499
1097
168
128
44.4
59.0
56.6
5.0
2.4
84.7


3
566
1136
161
121
43.0
57.6
54.2
3.6
1.0
85.8


17
603
1048
217
125
45.0
57.7
57.2
3.7
1.1
79.3


15
639
1139
221
110
43.6
57.1
56.9
3.1
0.5
80.6


10
850
1164
186
113
44.1
59.0
58.2
5.0
2.4
84.0


11
841
1120
172
121
44.0
59.3
57.9
5.3
2.6
84.6


16
786
1089
193
125
44.7
58.4
57.6
4.4
1.8
82.3


14
618
1111
218
115
43.8
57.4
57.8
3.3
0.7
80.4


13
621
1091
209
115
44.0
57.3
57.8
3.3
0.7
80.8


12
755
1094
191
112
44.0
58.1
56.8
4.1
1.5
82.5


5
656
1175
223
110
42.7
57.5
56.4
3.5
0.9
81.0


6
618
1156
209
153
43.3
57.7
55.2
3.6
1.0
81.9


7
574
1140
319
122
42.7
54.6
56.9
0.6
−2.0
72.1


8
454
1115
322
115
44.6
55.5
57.1
1.4
−1.2
71.1









In addition to the results in Table 12, the following was observed: tests 6 and 10-16 had too much rejects. For this Example a reject amount over about 570-600 g was considered too high a yield loss.
The results of the deinking tests for Example 3 are shown graphically in FIG. 7-9. A review of these figures shows that a blend of lipase and xylanase at either a ratio of 67/33 or 50/50 and a cell level of 3750 g performed better than conventional or sulfite based neutral deinking. Much of the study was conducted at a level of 4200 g which rejected too much material even with reduced enzyme dosage level. Reducing the lipase dosage to 0.0075% with 0.015% Xylanase almost gave acceptable rejects level at a cell level of 4200 g of stock. Adding hydrogen peroxide with sodium sulfite gave higher flot accept brightness but lower hyperwash brightness (less bleaching). Hydrogen peroxide without sodium sulfite gave lower flot accept brightness and higher hyperwash brightness.
Examples 4 and 5
The pulping recipes used in Examples 4 and 5 (Tests 1-30) are listed below in Table 13. The specific pulping components and conditions were: 17.5 grams each of WSJ and LAT (Example 4) and 35 grams of Globe and Mail mixed (Example 5), flotation time of 8 min, and air rate of 20 SCHF. The pH operating ranges for Examples 4 and 5 are listed below in Table 14.







TABLE 13







Pulping recipes for tests 1-30 (Examples 4 and 5).

















Cell






Pulp



Test
Level,

Deinking

Xylanase
Lipase

Liquor


#
grams
Pulper
Agents
Sulfite
%
%
Ratio
pH
FF pH



















1
4200
Conventional LAT-
Eka RF 4291 +



NA
11.0
9.1




WSJ
Eka RF 4031


3
4200
Neutral w/Sodium
Eka RF 4291 +
Yes


NA
9.57
7.54




Sulfite LAT-WSJ
Eka RF 4031


9
4200
Conventional +
Eka RF 4291 +

0.0150
0.0750
66/34
11.22
9.09




Blend LAT-WSJ
Eka RF 4031


22
4200
NaSul + Blend LAT-
Eka RF 4291 +
Yes
0.0100
0.0050
66/34
9.65
7.68




WSJ
Eka RF 4031


17
4200
NaSul + E6634 LAT-
Eka RF 4291 +
Yes
0.0100
0.0050
66/34
9.56
7.70




WSJ
Eka RF 4031


21
4200
NaSul + Blend LAT-
Eka RF 4291 +
Yes
0.0140
0.0070
66/34
9.62
7.63




WSJ
Eka RF 4031


19
4200
NaSul + E6634 LAT-
Eka RF 4291 +
Yes
0.0140
0.0070
66/34
9.56
8.18




WSJ
Eka RF 4031


13
4200
NaSul + Blend LAT-
Eka RF 4291 +
Yes
0.0075
0.0075
50/50
9.62
7.53




WSJ
Eka RF 4031


14
4200
NaSul + E5050 LAT-
Eka RF 4291 +
Yes
0.0075
0.0075
50/50
9.62
7.53




WSJ
Eka RF 4031


6
4200
NaSul + Blend LAT-
Eka RF 4291 +
Yes
0.0140
0.0075
65/35
9.55
7.57




WSJ
Eka RF 4031


15
4200
NaSul + E6634 LAT-
Eka RF 4291 +
Yes
0.0200
0.0100
66/34
9.59
7.64




WSJ
Eka RF 4031


5
4200
NaSul + Blend LAT-
Eka RF 4291 +
Yes
0.0140
0.0750
65/35
9.45
7.50




WSJ
Eka RF 4031


12
4200
NaSul + Blend LAT-
Eka RF 4291 +
Yes
0.0150
0.0150
50/50
9.54
7.46




WSJ
Eka RF 4031


25
4200
NaSul + E6634 in 4291
0.0825%
Yes
0.0150
0.0075
66/34
9.60
7.63




LAT-WSJ
RF4291-E6634


26
4200
NaSul + E6634 in 4031
0.5225%
Yes
0.0150
0.0075
66/34
9.54
7.69




LAT-WSJ
RF4031-E6634


11
4200
NaSul + E5050 LAT-
Eka RF 4291 +
Yes
0.1500
0.1500
50/50
9.58
7.61




WSJ
Eka RF 4031


29
4200
Blend LAT-WSJ
Eka RF 4291 +

0.0140
0.0050
74/26
9.48
6.98





Eka RF 4031


27
4200
Blend LAT-WSJ
Eka RF 4291 +

0.0140
0.0070
66/34
9.47
7.16





Eka RF 4031


23
4200
E6634 LAT-WSJ
Eka RF 4291 +

0.0140
0.0070
66/34
9.44
7.42





Eka RF 4031


10
4200
Conventional GLOBE
Eka RF 4291 +



NA
10.96
9.05





Eka RF 4031


4
4200
Neutral w/Sodium
Eka RF 4291 +
Yes


NA
9.35
7.62




Sulfite GLOBE
Eka RF 4031


20
4200
NaSul + E6634 GLOBE
Eka RF 4291 +
Yes
0.0200
0.0100
66/34
9.56
7.58





Eka RF 4031


7
4200
NaSul + H2O2 GLOBE
Eka RF 4291 +
Yes


NA
9.44
7.21





Eka RF 4031


8
4200
H2O2 GLOBE
Eka RF 4291 +



NA
9.26
6.85





Eka RF 4031


28
4200
Blend GLOBE
Eka RF 4291 +

0.0140
0.0070
66/34
9.31
7.59





Eka RF 4031


30
4200
NaSul + E6634 GLOBE
Eka RF 4291 +
Yes
0.1400
0.0070
66/34
9.56
8.04





Eka RF 4031
















TABLE 14







pH ranges for Examples 4 and 5 for neutral deinking.











Pulping Flot



Pulping Liquor
Feed















Max pH
9.7
8.2



Min pH
9.3
6.9










The deinking performance of the various test recipes were evaluated and the results are shown below in Table 15.







TABLE 15







Deinking Results for tests 1-30 (Examples 4 and 5).


















Wet






Brightness
Brightness
Removal


Test
Reject
ERIC
ERIC
ERIC
Brightness
Brightness
Brightness
Difference
Difference
Efficiency


#
Wt.
Pulper
Flot
Hyper
Pulper
Flot
Hyper
vs. Conv
vs. Sulfite
at Flot




















1
635
948
211
115
45.0
56.6
59.1
NA
−1.4
77.7


3
686
981
199
131
45.0
58.0
57.6
1.4
NA
79.7


9
1196
950
150
123
46.1
58.6
57.8
2.0
0.7
84.3


22
895
920
176
134
46.0
58.8
56.7
2.2
0.8
80.9


17
929
925
181
136
45.4
58.8
55.8
2.2
0.8
80.5


21
1019
917
163
134
45.3
58.8
57.1
2.2
0.9
82.3


19
722
1161
165
106
43.3
54.6
54.0
−2.0
−3.3
85.8


13
1035
901
153
125
45.2
58.9
57.8
2.3
0.9
83.0


14
949
950
178
126
45.2
58.6
56.8
2.0
0.6
81.3


6
817
1000
194
127
44.7
58.4
57.1
1.8
0.4
80.6


15
959
935
178
122
45.5
58.7
57.6
2.1
0.7
80.9


5
1104
1007
158
115
44.5
59.1
57.3
2.5
1.1
84.3


12
1092
969
168
121
45.9
59.2
57.7
2.6
1.2
82.6


25
912
894
168
111
45.6
58.5
56.9
1.9
0.6
81.2


26
684
916
187
137
45.0
57.8
56.2
1.3
−0.1
79.6


11
1168
979
150
120
45.0
59.0
56.8
2.4
1.0
84.7


29
1095
863
190
124
45.8
57.5
56.7
0.9
−0.5
77.9


27
848
903
201
134
45.8
57.3
56.2
0.7
−0.7
77.8


23
844
884
181
141
45.7
57.8
56.0
1.2
−0.2
79.6


10
656
1145
200
83
44.1
55.4
57.6
NA
1.0
82.5


4
797
1220
193
94
42.2
54.4
52.6
−1.0
NA
84.2


20
1058
939
160
127
46.0
59.0
57.1
3.6
4.6
82.9


7
798
1135
171
103
42.5
54.8
54.9
−0.6
0.4
85.0


8
772
1119
177
120
43.3
55.3
54.9
−0.1
0.9
84.2


28
698
1007
180
104
43.4
53.9
54.0
−1.5
−0.5
82.1


30
1141
1126
153
105
44.4
55.8
55.1
0.5
1.4
86.4









In addition to the results in Table 15, the following was observed: tests 5, 9, 11-15, 17, 20-22, 25, 29 and 30 had too much wet rejects. For this Example a reject amount over about 850 g was considered too high a yield loss.
The results of the deinking tests for Examples 4 and 5 are shown graphically in FIG. 10-15. A review of these figures shows that a mixture of lipase and xylanase at either a ratio of 66/34 or 50/50 was compared to enzymes added separately and blended in pulper. The results were found to be the same or better when enzymes were mixed. Addition of enzymes to non-ionic surfactant gave better ink detachment and is best option if reject level is controlled. Removing the sodium sulfite lowered the amount of rejects in most cases. The Globe and Mail furnish saw no benefit adding peroxide with the sulfite chemistry and a slight benefit with sodium sulfite. Higher dosages of enzymes did not increase deinking performance.
Example 6 and 7
The pulping recipes used in Examples 6 and 7 (Tests 1 to 17) are listed below in Table 16. The specific pulping components and conditions were: 17.5 grams each of WSJ and LAT (Example 6) and 35 grams of Globe and Mail mixed (Example 7), flotation time of 8 min, and air rate of 20 SCHF. The pH operating ranges for Examples 6 and 7 are listed below in Table 17.







TABLE 16







Pulping recipes for tests 1-17 (Examples 6 and 7).

















Cell






Pulp



Test
Level,

Deinking

Xylanase
Lipase

Liquor


#
grams
Pulper
Agents
Sulfite
%
%
Ratio
pH
FF pH



















1
4200
Conventional 70
Eka RF 4291 +



NA
11.2
9.1




LAT-WSJ
Eka RF 4031


9
4200
Neutral w/Sodium
Eka RF 4291 +
Yes


NA
9.6
8.4




Sulfite 70 LAT-
Eka RF 4031




WSJ


12
4200
NaSul + E6634 70
Eka RF 4291 +
Yes
0.013
0.007
66/34
9.6
8.4




LAT-WSJ
Eka RF 4031


3
4200
Conventional 90
Eka RF 4291 +



NA
11.2
9.5




LAT-WSJ
Eka RF 4031


11
4200
Neutral w/Sodium
Eka RF 4291 +
Yes


NA
9.5
8.4




Sulfite 90 LAT-
Eka RF 4031




WSJ


14
4200
NaSul + E6634 90
Eka RF 4291 +
Yes
0.013
0.007
66/34
9.6
8.2




LAT-WSJ
Eka RF 4031


4
4200
Conventional 100
Eka RF 4291 +



NA
11.1
9.0




LAT-WSJ
Eka RF 4031


16
4200
NaSul + E6634 100
Eka RF 4291 +
Yes
0.013
0.007
66/34
9.5
8.4




LAT-WSJ
Eka RF 4031


5
4200
Conventional 70
Eka RF 4291 +



NA
11.1
9.0




Globe
Eka RF 4031


10
4200
Neutral w/Sodium
Eka RF 4291 +
Yes


NA
9.6
8.1




Sulfite 70 Globe
Eka RF 4031


13
4200
NaSul + E6634 70
Eka RF 4291 +
Yes
0.013
0.007
66/34
9.5
8.2




Globe
Eka RF 4031


7
4200
Conventional 90
Eka RF 4291 +



NA
11.1
9.0




Globe
Eka RF 4031


15
4200
NaSul + E6634 90
Eka RF 4291 +
Yes
0.013
0.007
66/34
9.6
8.1




Globe
Eka RF 4031


8
4200
Conventional
Eka RF 4291 +



NA
11.1
8.9




100 Globe
Eka RF 4031


17
4200
NaSul + E6634
Eka RF 4291 +
Yes
0.013
0.007
66/34
9.6
7.8




100 Globe
Eka RF 4031
















TABLE 17







pH ranges for Examples 6 and 7 for neutral deinking.










Pulping Liquor




pH
FF pH















Max pH
9.6
8.4



Min pH
9.5
7.8










The deinking performance of the various test recipes were evaluated and the results are shown below in Table 18.







TABLE 18







Deinking Results for tests 1-30 (Examples 6 and 7).


















Wet






Brightness
Brightness
Removal


Test
Reject
ERIC
ERIC
ERIC
Brightness
Brightness
Brightness
Difference
Difference
Efficiency


#
Wt.
Pulper
Flot
Hyper
Pulper
Flot
Hyper
vs. Conv
vs Sulfite
at Flot




















1
510
1275
475
132
46.2
56.3
61.3
NA
1.0
72.2


9
681
1384
442
149
44.6
55.3
57.0
−1.0
NA
66.2


12
644
1448
337
133
44.1
57.2
58.3
0.9
1.9
60.4


3
340
1281
510
157
45.7
53.8
59.1
NA
1.2
69.3


11
543
1268
505
166
44.7
52.6
56.3
−1.2
NA
67.3


14
729
1308
399
180
44.6
54.4
56.0
0.7
1.8
54.9


4
370
1304
525
170
43.6
51.4
57.5
NA
−2.0  
67.7


16
491
1236
413
201.2
45.2
53.4
54.2
2.0
NA
51.3


5
450
1137
350
83
44.9
53.7
57.5
NA
1.5
76.4


10
496
1218
347
87
43.1
52.2
53.9
−1.5
NA
74.8


13
510
1249
318
81.85
43.2
53.2
54.2
−0.5
1.0
74.2


7
269
1328
644
98
40.1
46.6
54.8
NA
NA
84.8


15
279
1569
635
117.3
38.8
46.3
51.5
−0.3
NA
81.5


8
249
1603
1480
147
37.2
37.9
52.9
NA
NA
90.1


17
205
1557
1339
176.6
38.5
39.8
50.4
1.9
NA
86.8









For this Example a reject amount over about 700 g was considered too high a yield loss. In addition to the results in Table 18, the following was observed: tests 14 had too much wet rejects.
The results of the deinking tests for Examples 6 and 7 are shown graphically in FIGS. 16-21. As expected increasing ONP content dropped the amount of rejects and lowered brightness. The addition of the mixture of enzymes with sulfite based neutral deinking gave higher flot accept brightness than conventional of 1 (70%), 0.5 (90%) and 2 (100%) points for the LAT/WSJ combination in Example 6. For Example 7, Globe and Mail it was −0.5 (70%), −0.3 (90%) and 2 (100%) points. The foaming nature helped when using 100% ONP for both examples. The ink type for the Globe and Mail showed a significant drop in brightness and ability to be deinked when going to 100% ONP due to low levels of rejects. The use of this enzyme mixture will allow mills to use a higher ONP content while maintaining deinking performance.
Example 8
The pulping recipes used in Example 8 (Tests 1 to 7) are listed below in Table 19. The specific pulping components and conditions were: 17.5 grams each of WSJ and LAT, flotation time of 8 min, and air rate of 20 SCHF. The pH operating ranges for Example 8 is listed below in Table 20.







TABLE 19







Pulping recipes for tests 1-7 (Example 8).

















Cell






Pulp



Test
Level,

Deinking

Xylanase
Lipase

Liquor


#
grams
Pulper
Agents
Sulfite
%
%
Ratio
pH
FF pH



















1
4200
Conventional
Eka RF



NA
11.3
8.9





4291 + Eka





RF 4031


3
4200
Neutral with
Eka RF
Yes


NA
9.6
7.2




Sodium Sulfite
4291 + Eka




LAT
RF 4031


4
4200
E5050
Eka RF

0.01
0.01
50/50
9.3
6.9





4291 + Eka





RF 4031


5
4200
E6634
Eka RF

0.013
0.007
66/34
9.3
7.2





4291 + Eka





RF 4031


6
4200
E7525
Eka RF

0.015
0.005
75/25
9.4
7.2





4291 + Eka





RF 4031


7
4200
Blend
Eka RF

0.015
0.005
75/25
9.7
7.2





4291 + Eka





RF 4031
















TABLE 20







pH ranges for Example 8 for neutral deinking.










Pulping Liquor




pH
FF pH















Max pH
9.7
7.2



Min pH
9.3
6.9










The deinking performance of the various test recipes were evaluated and the results are shown below in Table 21.







TABLE 21







Deinking Results for tests 1-7 (Example 8).


















Wet






Brightness
Brightness
Removal


Test
Reject
ERIC
ERIC
ERIC
Brightness
Brightness
Brightness
Difference
Difference
Efficiency


#
Wt.
Pulper
Flot
Hyper
Pulper
Flot
Hyper
vs. Conv
vs Sulfite
at Flot




















1
932
759
206
110
45.6
56.3
58.1
NA
1.2
72.9


3
897
729
225
126
45.5
56.1
55.7
0.9
NA
69.1


4
1367
681
202
143
45.4
55.4
54.4
0.3
0.4
70.4


5
1229
714
207
145
45.2
55.1
55.2
0.0
0.1
71.0


6
1166
727
223
139
45.2
55.0
55.0
−0.1
0.0
69.4


7
1009
677
243
140
45.7
54.7
54.1
−0.5
−0.4
64.2









For this Example a reject amount over about 1130 g was considered too high a yield loss. In addition to the results in Table 21, the following was observed: tests 4 to 6 had too much wet rejects.
The results of the deinking tests for Example 8 are shown graphically in FIGS. 22-24. This study looked at removing sodium sulfite and at ratios of xylanase/lipase of 50/50, 66/34 and 75/25 with a dosage of 0.02%. Going to a ratio of 75/25 dropped the reject level to an acceptable level. Mixing the two together gave about 0.5 points better brightness than adding the two enzymes separately and a lower rejects level. Flot Accept brightness was lower than conventional for this study but within the two point criteria and a difference of about 1.2 points. The study also showed further adjustments needed to control the amount of wet rejects when the sodium sulfite was removed.
Example 9
The pulping recipes used in Example 9 (Tests 1 to 14) are listed below in Table 22. The specific pulping components and conditions were: 17.5 grams each of WSJ and LAT, flotation time of 8 min, and air rate of 20 SCHF. The pH operating ranges for Example 8 is listed below in Table 23.







TABLE 22







Pulping recipes for tests 1-14 (Example 9).

















Cell






Pulp



Test
Level,

Deinking

Xylanase
Lipase

Liquor


#
grams
Pulper
Agents
Sulfite
%
%
Ratio
pH
FF pH



















1
4200
conv
Eka RF 4291 +



NA
11.7
9.3





Eka RF 4031


3
4200
S-Quad
Eka RF 4291 +
Yes


NA
9.5
9.4





Eka RF 4031


8
4200
no sulfite
Eka RF 4291 +



NA
8.8
7.2




P0.5—NI 0.03—Si 0.5
Eka RF 4031


9
4200
no sulfite
Eka RF 4291 +



NA
9.1
7.2




P1.5—NI 0.03—Si 1.5
Eka RF 4031


13
4200
no sulfite
Eka RF 4291 +



NA
9.0
7.2




P 0.5—NI 0.06—Si 1.0
Eka RF 4031


11
4200
no sulfite
Eka RF 4291 +



NA
9.1
7.2




P0.5—NI 0.09—Si 1.5
Eka RF 4031


5
4200
no sulfite
Eka RF 4291 +



NA
9.2
7.1




P1.0—NI 0.06—Si 1.0
Eka RF 4031


14
4200
no sulfite
Eka RF 4291 +



NA
9.3
7.2




P51 1.0—NI 0.06—Si 1.5
Eka RF 4031


4
4200
no sulfite
Eka RF 4291 +



NA
8.9
7.3




P1.5—NI 0.03—Si 0.5
Eka RF 4031


7
4200
no sulfite
Eka RF 4291 +



NA
9.1
7.1




P1.5—NI 0.09—Si 0.5
Eka RF 4031


12
4200
no sulfite
Eka RF 4291 +



NA
9.2
7.2




P1.5—NI 0.09—Si 0.5
Eka RF 4031
















TABLE 23







pH ranges for Example 9 for neutral deinking












Pulping Liquor




Neutral Deinking pH range
pH
FF pH







Max pH
9.5
9.4



Min pH
8.8
7.1










The deinking performance of the various test recipes were evaluated and the results are shown below in Table 24.







TABLE 24







Deinking Results for tests 1-14 (Example 9).


















Wet






Brightness
Brightness
Removal


Test
Reject
ERIC
ERIC
ERIC
Brightness
Brightness
Brightness
Difference
Difference
Efficiency


#
Wt.
Pulper
Flot
Hyper
Pulper
Flot
Hyper
vs. Conv
vs Sulfite
at Flot




















1
721
1157
403
155
41.1
48.0
50.5
NA
−3.0
61.5


3
735
1203
380
181
43.6
53.2
53.6
1.9
NA
52.4


8
683
1260
456
231
42.8
51.8
52.7
0.5
0.9
49.3


9
593
1272
511
236
42.8
51.3
52.0
0.0
0.4
53.7


13
633
1141
517
215
43.8
50.9
49.8
−0.4
0.0
58.5


11
444
1342
611
249
42.5
50.5
51.4
−0.8
−0.4
59.3


5
601
1260
463
233
42.7
52.0
52.5
0.7
1.0
49.6


14
563
1204
562
232
43.7
51.0
52.1
−0.3
0.1
58.8


4
782
1289
423
208
42.8
52.6
53.3
1.3
1.7
50.9


7
726
1175
408
229
42.4
51.5
51.4
0.2
0.6
43.9


12
656
1311
437
248
42.2
52.3
51.7
1.0
1.4
43.3









For this Example a reject amount over about 920 g was considered too high a yield loss. In addition to the results in Table 24, the following was observed: no tests had too much wet rejects.
The results of the deinking tests for Example 9 are shown graphically in FIGS. 25-26. This study looked at adding hydrogen peroxide without adding caustic and without adding sodium sulfite. A testing error resulted in no hydrogen peroxide being added to the conventional pulper chemistry which produced darker paper due to bleach removal and caustic yellowing. The removal of sodium sulfite and the enzymes resulted in a large increase in ink redeposition as seen with ERIC hyperwash averaging 226 for neutral deinking. Dropping the sodium silicate dosage to 0.5% gave better ink removal and higher brightness but was due to a higher amount of rejects. The sodium silicate is helping to reduce reject volume during neutral deinking.
Example 10
The pulping recipes used in Example 10 (Tests 1 to 14) are listed below in Table 25. The specific pulping components and conditions were: 35 grams each of WSJ, LAT or Globe and Mail, flotation time of 5 min, and air rate of 15 SCHF. The pH operating ranges for Example 10 is listed below in Table 26.







TABLE 25







Pulping recipes for tests 1-14 (Example 10).

















Cell






Pulp



Test
Level,

Deinking

Xylanase
Lipase

Liquor


#
grams
Pulper
Agents
Sulfite
%
%
Ratio
pH
FF pH



















1
4200
Conventional -
Eka RF 4291 +



NA
11.02
9.24




LAT
Eka RF 4031


13
4200
Neutral with
Eka RF 4291 +
Yes


NA
9.63
8.50




Sodium Sulfite
Eka RF 4031




LAT


14
4100
E6634 LAT-
Eka RF 4291 +

0.013
0.07
66/34
9.54
8.13




4100
Eka RF 4031


3
4200
Conventional -
Eka RF 4291 +



NA
11.02
9.58




WSJ
Eka RF 4031


4
4200
Neutral with
Eka RF 4291 +
Yes


NA
9.52
8.34




Sodium
Eka RF 4031




Sulfite-WSJ


5
4100
E6634-WSJ-
Eka RF 4291 +

0.013
0.07
66/34
9.34
8.45




4100
Eka RF 4031


2
4200
Conventional -
Eka RF 4291 +



NA
11.03
9.02




GLOBE
Eka RF 4031


8
4200
Neutral with
Eka RF 4291 +
Yes


NA
9.64
8.01




Sodium Sulfite -
Eka RF 4031




GLOBE


7
4100
E6634 -
Eka RF 4291 +

0.013
0.07
66/34
9.32
7.86




GLOBE-4100
Eka RF 4031
















TABLE 26







pH ranges for Example 10 for neutral deinking












Pulping Liquor




Neutral Deinking pH range
pH
FF pH







Max pH
9.6
8.5



Min pH
9.3
7.9










The deinking performance of the various test recipes were evaluated and the results are shown below in Table 27.







TABLE 27







Deinking Results for tests 1-14 (Example 10).


















Wet






Brightness
Brightness
Removal


Test
Reject
ERIC
ERIC
ERIC
Brightness
Brightness
Brightness
Difference
Difference
Efficiency


#
Wt.
Pulper
Flot
Hyper
Pulper
Flot
Hyper
vs. Conv
vs Sulfite
at Flot




















1
180
937
461
201
42.02
48.03
53.94
NA
−1.4
56.4


13
242
1202
382
243
38.62
49.45
50.15
1.4
NA
36.3


14
87
958
421
177
41.26
48.39
48.16
0.4
−1.1
57.9


3
388
932
310
107
48.30
57.39
59.84
NA
−0.2
65.6


4
388
976
343
141
47.75
57.58
58.14
0.2
NA
59.0


5
308
889
338
212
49.10
57.22
57.59
−0.2
−0.4
37.1


2
491
1005
345
141
45.62
53.83
56.96
NA
−0.1
59.0


8
582
1284
298
190
42.33
53.96
54.20
0.1
NA
36.4


7
649
944
308
141
44.95
52.95
53.97
−0.9
−1.0
54.2









For this Example a reject amount over about 380 g (LA Times), 590 (WSJ) or 690 (Globe and Mail) was considered too high a yield loss. In addition to the results in Table 27, the following was observed: no tests had too much wet rejects.
The results of the deinking tests for Example 10 are shown graphically in FIGS. 27-29. Reject levels have been an issue in the development effort. In this study the amount of air injected was dropped from 20 to 15 scfm. Also the cell level was dropped to 4100 g from 4200 g when using the enzymes. This study looks at deinking performance of neutral deinking with no sodium sulfite but with enzymes and is compared to conventional deinking and sulfite based neutral deinking. This comparison in pulper chemistry was made using the Los Angles Times (LAT), the Wall Street Journal (WSJ) and the Globe and Mail (GLOBE). Dropping the air flow rate and a drop to 4100 g cell level for neutral deinking with enzymes without sodium sulfite gave similar reject losses to conventional and a sodium sulfite based pulper chemistry. This study showed the combination of xylanase and lipase at 66/34 at a dose of 0.2% gave equal deinking performance to conventional or sulfite neutral deinking. The worse performance was for the Globe and Mail after flotation and it was within 1 point of conventional.
Example 11
The pulping recipes used in Example 11 (Tests 1 to 23) are listed below in Table 28. A portion of the tests were not related to this study and are not included. The specific pulping components and conditions were: 35 grams each of WSJ, LAT or Globe and Mail, flotation time of 5 min, and air rate of 15 SCHF. The pH operating ranges for Example 11 is listed below in Table 29.







TABLE 28







Pulping recipes for tests 1-23 (Example 11).

















Cell






Pulp



Test
Level,

Deinking

Xylanase
Lipase

Liquor


#
grams
Pulper
Agents
Sulfite
%
%
Ratio
pH
FF pH



















1
4200
Conventional-
Eka RF 4291 +



NA
12.0
9.8




LAT-4200
Eka RF 4031


13
4200
Neutral w/Sodium
Eka RF 4291 +
Yes


NA
9.6
8.3




Sulfite LAT-4200
Eka RF 4031


14
4100
E6634 LAT-4100
Eka RF 4291 +

0.013
0.007
66/34
9.4
8.2





Eka RF 4031


22
4100
XP 5313 LAT-
Eka RF 4291 +

0.013
0.007
66/34
9.4
7.8




4100
Eka RF 4031


3
4200
Conventional-
Eka RF 4291 +



NA
12.2
10.0




WSJ-4200
Eka RF 4031


4
4200
Neutral w/Sodium
Eka RF 4291 +
Yes


NA
10.2
8.3




Sulfite WSJ-4200
Eka RF 4031


5
4100
E6634 WSJ-4100
Eka RF 4291 +

0.013
0.007
66/34
9.6
8.1





Eka RF 4031


2
4100
Conventional-
Eka RF 4291 +



NA
12.1
8.7




GLOBE
Eka RF 4031


8
4000
Neutral w/Sodium
Eka RF 4291 +
Yes


NA
10.2
7.7




Sulfite GLOBE-
Eka RF 4031




4000


7
4000
E6634 GLOBE-
Eka RF 4291 +

0.013
0.007
66/34
9.5
7.7




4000
Eka RF 4031


23
4000
XP 5313
Eka RF 4291 +

0.013
0.007
66/34
9.5
7.6




GLOBE-4000
Eka RF 4031
















TABLE 29







pH ranges for Example 10 for neutral deinking












Pulping Liquor




Neutral Deinking pH range
pH
FF pH















Max pH
10.2
8.3



Min pH
9.4
7.6










The deinking performance of the various test recipes were evaluated and the results are shown below in Table 30.







TABLE 30







Deinking Results for tests 1-23 (Example 11).


















Wet






Brightness
Brightness
Removal


Test
Reject
ERIC
ERIC
ERIC
Brightness
Brightness
Brightness
Difference
Difference
Efficiency


#
Wt.
Pulper
Flot
Hyper
Pulper
Flot
Hyper
vs. Conv
vs Sulfite
at Flot




















1
317
924
380
124
44.3
51.1
53.0
NA
2.5
58.9


13
373
1181
429
116
40.3
48.6
48.1
−2.5
NA
63.6


14
248
1147
447
180
40.5
48.1
46.6
−3.0
−0.5
61.1


22
359
1011
288
151
40.3
49.3
45.9
−1.8
0.7
71.5


3
450
957
292
156
47.5
58.8
58.2
NA
0.9
69.5


4
501
988
267
192
46.2
57.9
56.6
−0.9
NA
73.0


5
357
1037
367
176
45.5
55.0
55.2
−3.8
−2.9
64.6


2
490
1055
331
143
44.8
54.3
55.0
NA
0.3
68.6


8
662
1284
301
180
42.1
54.1
53.3
−0.3
NA
76.6


7
492
1127
353
140
42.6
51.6
52.0
−2.7
−2.5
68.7


23
703
1174
294
181
42.3
51.9
51.7
−2.5
−2.2
74.9









For this Example a reject amount over about 380 g (LA Times), 590 (WSJ) or 690 (Globe and Mail) was considered too high a yield loss. In addition to the results in Table 30, the following was observed: test 23 was barely above having too much wet rejects.
The results of the deinking tests for Example 11 are shown graphically in FIGS. 30-32. The amount of ink redeposited also varied significantly indicating easy to very difficult to deink based on the ERIC hyperwash value as shown in Table 31. In general this example did not meet the within 2 point criteria and was mainly due to the more difficult nature of the ONP based on the aging effect as seen by an increase in the ERIC value of the hyperwashed pulp. This example included blending the mixture of enzymes with a non-ionic surfactant which preformed better than the other neutral deinking pulper recipes for the LA Times and Globe and Mail. The blended mixture condition was not run for the Wall Street Journal.







TABLE 31







Comparison of the amount of attached redeposited ink based on ONP


used (Example 11).















Conventional


Old Newsprint
Neutral
Conventional
Deinking
Rejects





LAT Average HW
210
201
very difficult
180


WSJ Average HW
177
107
easy
388


GLOBE Average
165
141
difficult
491


HW









Example 12
The pulping recipes used in Example 12 are listed below in Table 32. A portion of the tests were not related to this study and are not included or were repeats averaged into the reported results. The specific pulping components and conditions were: 17.5 grams each of WSJ and LAT, flotation time of 5 min, and air rate of 15 SCHF. The pH operating ranges for Example 12 is listed below in Table 33.







TABLE 32







Pulping recipes (Example 12).

















Cell






Pulp



Test
Level,

Deinking

Xylanase
Lipase

Liquor


#
grams
Pulper
Agents
Sulfite
%
%
Ratio
pH
FF pH




















4200
Conventional
Eka RF 4291 +



NA
11.3
9.6





Eka RF 4031



4200
Conventional
Eka NA120 +



NA
11.4
9.6





Eka RF 4031


5
4200
Neutral w/
Eka RF 4291 +
Yes


NA
9.8
8.5




NaSul - RF
Eka RF 4031




4291


8
4200
Neutral
Eka NA120 +
Yes


NA
9.8
8.6




w/NaSul- 120
Eka RF 4031




NA


9
4100
Neutral/No
Eka RF 4291 +



NA
9.6
8.5




NaSul - RF
Eka RF 4031




4291


10
4100
Neutral/No
Eka NA120 +



NA
9.6
8.6




NaSul - 120
Eka RF 4031




NA



4100
E6634 - RF
Eka RF 4291 +

0.013
0.07
66/34
9.6
8.5




4291
Eka RF 4031



4100
E6634 - NA
Eka NA120 +

0.013
0.07
66/34
9.6
8.6




120
Eka RF 4031
















TABLE 33







pH ranges for Example 12 for neutral deinking












Pulping Liquor




Neutral Deinking pH range
pH
FF pH







Max pH
9.8
8.6



Min pH
9.6
8.5










For this Example a reject amount over about 1030 g (Eka RF 4291) or 920 (Eka NA120) was considered too high a yield loss. In addition to the results in Table 34, the following was observed: none of the tests had too much wet rejects.
The results of the deinking tests for Example 12 are shown graphically in FIGS. 33-35. The paper used in this study was very difficult to deink as denoted by having a hyperwash ERIC value of about 250 for conventional deinking due to the age of the paper. The study showed under these challenging conditions that the addition of the enzyme mixture of 66% xylanase and 33% lipase without sodium sulfite gave comparable deinking performance to conventional and to sodium sulfite based neutral deinking. The study also showed that a deinking agent beside Eka RF 4291 could be used for neutral deinking. The study also showed that in general Eka RF 4291 was a better deinking agent than the current formula used to make Eka NA 120.







TABLE 34







Deinking Results (Example 12).


















Wet






Brightness
Brightness
Removal


Test
Reject
ERIC
ERIC
ERIC
Brightness
Brightness
Brightness
Difference
Difference
Efficiency


#
Wt.
Pulper
Flot
Hyper
Pulper
Flot
Hyper
vs. Conv
vs Sulfite
at Flot





















826
1185
379
245
43.7
55.6
56.7
NA
0.2
68



721
1202
458
261
43.1
54.8
55.9
NA
2.0
62


5
939
1299
365
279
41.7
55.3
54.9
−0.2
NA
71.9


8
808
1307
491
291
41.8
52.8
54.5
−2.0
NA
62.5


9
685
1352
439
274
41.5
53.5
54.6
−2.1
−1.8
67.5


10
707
1355
491
313
41.2
52.5
53.9
−2.3
−0.3
63.8



858
1301
388
298
42.0
54.4
53.7
−1.2
−1.0
70



878
1244
370
291
41.6
54.5
53.6
−0.3
1.7
70









Example 13
The pulping recipes used in Example 13 (Tests 1-14) are listed below in Table 35. The specific pulping components and conditions were: 17.5 grams each of WSJ and LAT, flotation time of 5 min, and air rate of 15 SCHF. The pH operating ranges for Example 13 is listed below in Table 36.







TABLE 35







Pulping recipes for tests 1-14 (Example 13).

















Cell






Pulp



Test
Level,

Deinking

Xylanase
Lipase

Liquor


#
grams
Pulper
Agents
Sulfite
%
%
Ratio
pH
FF pH



















1
4200
Conventional-
Eka RF 4291 +



NA
11.5
9.5




NaOH 1%
Eka RF 4031


3
4200
Conventional-
Eka RF 4291 +



NA
11.1
9.2




NaOH 0.6%
Eka RF 4031


4
4200
Conventional-
Eka RF 4291 +



NA
10.6
8.9




NaOH 0.3%
Eka RF 4031


5
4200
Conventional-
Eka RF 4291 +



NA
10.2
8.6




NaOH 0.15%
Eka RF 4031


6
4200
Conventional-
Eka RF 4291 +



NA
9.5
8.5




NaOH 0.03%
Eka RF 4031


2
4200
Neutral
Eka RF 4291 +
Yes


NA
9.5
8.6




w/NaSulfite
Eka RF 4031


8
4100
Neutral
Eka RF 4291 +



NA
9.5
8.5




wo/NaSulfite
Eka RF 4031


7
4100
E6634
Eka RF 4291 +

0.013
0.007
66/34
9.5
8.4





Eka RF 4031


9
4100
E6634-NaOH
Eka RF 4291 +

0.013
0.007
66/34
9.6
8.4




0.03%
Eka RF 4031


10
4100
E6634-NaOH
Eka RF 4291 +

0.013
0.007
66/34
9.9
8.7




0.08%
Eka RF 4031


11
4100
E6634-NaOH
Eka RF 4291 +

0.013
0.007
66/34
10.4
8.8




0.15%
Eka RF 4031


12
4100
E6634-NaOH
Eka RF 4291 +

0.013
0.007
66/34
11.0
9.1




0.3%
Eka RF 4031


13
4100
E6634-NaOH
Eka RF 4291 +

0.013
0.007
66/34
11.3
9.4




0.6%
Eka RF 4031


14
4100
E6634-NaOH
Eka RF 4291 +

0.013
0.007
66/34
11.5
10.1




1%
Eka RF 4031
















TABLE 36







pH ranges for Example 13 for neutral deinking












Pulping Liquor




Neutral Deinking pH range
pH
FF pH















Max pH
10.4
8.8



Min pH
9.5
8.4










For this Example a reject amount over about 1020 to 1070 g was considered too high a yield loss. In addition to the results in Table 37, the following was observed: none of the tests had too much wet rejects.
The results of the deinking tests for Example 13 are shown graphically in FIGS. 36-38. The paper used in this study was very difficult to deink as denoted by having a hyperwash ERIC value of about 240 for conventional deinking due to the age of the paper. The study showed under these challenging conditions that the addition of the enzyme mixture of 66% xylanase and 33% lipase without sodium sulphite gave comparable deinking performance to conventional and to sodium sulphite based neutral deinking. The study also showed that above 0.15% of caustic addition the loss of enzyme performance in conjunction with yellowing of fiber give a brightness a point lower than conventional and going above 0.3% lowered brightness by 2 points. With regards to pH, a value above 10 in the pulping liquor would be beyond the range of enzyme performance or a pH of 9 after pulping.







TABLE 37







Deinking Results for tests 1-14 (Example 13).


















Wet






Brightness
Brightness
Removal


Test
Reject
ERIC
ERIC
ERIC
Brightness
Brightness
Brightness
Difference
Difference
Efficiency


#
Wt.
Pulper
Flot
Hyper
Pulper
Flot
Hyper
vs. Conv
vs Sulfite
at Flot




















1
830
1318
433
239
43.3
54.7
55.9
NA
−1.4
67.1


3
860
1398
398
247
42.8
55.0
55.0
0.3
−1.1
71.6


4
853
1364
393
243
42.7
54.6
54.6
−0.1
−1.5
71.2


5
817
1430
421
258
41.9
55.2
54.9
0.5
−0.9
70.6


6
867
1420
416
299
42.5
55.3
54.9
0.5
−0.9
70.7


2
986
1420
344
248
42.3
56.1
54.7
1.4
NA
75.8


8
752
1417
431
261
42.6
54.6
53.7
−0.2
−1.6
69.6


7
744
1408
422
273
42.2
54.9
54.5
0.2
−1.2
70.0


9
788
1500
451
258
41.8
53.9
54.2
−0.8
−2.2
69.9


10
822
1426
409
262
42.4
54.9
54.4
0.2
−1.2
71.3


11
817
1463
438
264
41.7
54.4
53.6
−0.3
−1.7
70.1


12
808
1441
411
268
41.4
53.6
53.9
−1.1
−2.5
71.5


13
751
1381
422
250
41.5
52.9
53.2
−1.8
−3.2
69.4


14
820
1472
415
259
40.7
52.5
52.1
−2.2
−3.6
71.8









Example 14
The pulping recipes used in Example 14 (Tests 1-14) are listed below in Table 38. The specific pulping components and conditions were: 17.5 grams each of WSJ and LAT, flotation time of 5 min, and air rate of 15 SCHF. The pH operating ranges for Example 14 is listed below in Table 39. This study used a pulping consistency of 20%.







TABLE 38







Pulping recipes for tests 1-6 (Example 14).

















Cell






Pulp



Test
Level,

Deinking

Xylanase
Lipase

Liquor


#
grams
Pulper
Agents
Sulfite
%
%
Ratio
pH
FF pH



















1
4200
Conventional
Eka RF 4291 +



NA
11.45
9.16





Eka RF 4031


2
4200
Neutral w/
Eka RF 4291 +
Yes


NA
9.71
8.23




NaSul - RF 4291
Eka RF 4031


4
4100
XP 5313
XP 5313 at 0.045%

0.0075
0.00375
66/34
9.68
8.32




0.045%


6
4100
XP 5313
XP 5313 at 0.065%

0.011
0.0055
66/34
9.78
8.38




0.065%


3
4100
XP 5313 Tote
XP 5313-Tote at

0.0075
0.00375
66/34
9.59
8.06




0.045%
0.045%


5
4100
XP 5313 Tote
XP 5313-Tote at

0.011
0.0055
66/34
9.755
8.385




0.065%
0.065%
















TABLE 39







pH ranges for Example 14 for neutral deinking












Pulping Liquor




Neutral Deinking pH range
pH
FF pH







Max pH
9.8
8.4



Min pH
9.6
8.1










For this Example a reject amount over about 790 g was considered too high a yield loss. In addition to the results in Table 40, the following was observed: none of the tests had too much wet rejects.
The results of the deinking tests for Example 14 are shown graphically in FIGS. 39-41. The blend of xylanase and lipase with the non-ionic surfactant using either production grade product in a tote or from lab samples had a lower amount of residual ink and about 0.5 points brighter after flotation. The amount of attached/redeposited ink after hyperwashing was 150 for conventional and 196 with neutral deinking indicating difficult to deink old newsprint. The reject levels for neutral are equal to slightly lower indicating that increased solids loss was not the cause of better deinking performance.







TABLE 40







Deinking Results for tests 1-6 (Example 14).


















Wet






Brightness
Brightness
Removal


Test
Reject
ERIC
ERIC
ERIC
Brightness
Brightness
Brightness
Difference
Difference
Efficiency


#
Wt.
Pulper
Flot
Hyper
Pulper
Flot
Hyper
vs. Conv
vs Sulfite
at Flot




















1
586
975
286
159
43.6
54.9
56.1
NA
−1.0
70.6


2
664
1076
239
215
42.4
55.9
53.3
1.0
NA
77.8


4
608
1021
258
202
42.8
55.3
54.3
0.4
−0.6
74.7


6
490
1117
263
178
43.2
55.5
55.3
0.6
−0.4
76.5


3
585
1025
264
202
43.1
55.5
54.7
0.6
−0.4
74.2


5
524
1070
268
185
43.4
55.7
54.1
0.8
−0.2
74.9









Example 15
The pulping recipes used in Example 15 (Tests 1-14) are listed below in Table 41. The specific pulping components and conditions were: 50.0 grams mixture of old newspaper using flexographic ink and coated paper, flotation time of 5 min, and air rate of 15 SCHF. The pH operating ranges for Example 15 is listed below in Table 42. This study used a pulping consistency of 20%.







TABLE 41







Pulping recipes for tests 1-6 (Example 15).

















Cell






Pulp



Test
Level,

Deinking

Xylanase
Lipase

Liquor


#
grams
Pulper
Agents
Sulfite
%
%
Ratio
pH
FF pH



















1
4200
RF 4291 + Tall Oil
Eka RF 4291



NA
7.6
7.2


2
4200
RF 4283 + 4031
Eka RF 4283



NA
7.9
7.3


5
4200
RF 4283 + 4031
Eka RF 4283 +



NA
9.9
7.4




w/NaOH
Eka RF 4031


4
4200
RF 4283 + 4031
Eka RF 4283 +



NA
8.9
7.2




w/NaSilicate
Eka RF 4031


8
4200
RF 4283 + 4031
Eka RF 4283 +



NA
9.9
7.5




w/NaSilicate + NaOH
Eka RF 4031


3
4200
XP 5313 + 4031
XP 5313 +

0.008
0.004
66/34
8.0
7.2





Eka RF 4031


6
4200
XP 5313 + 4031
XP 5313 +

0.008
0.004
66/34
10.0
7.4




w/NaOH
Eka RF 4031


7
4200
XP 5313 + 4031
XP 5313 +

0.008
0.004
66/34
9.0
7.4




w/NaSilicate
Eka RF 4031


9
4200
XP 5313 + 4031
XP 5313 +

0.008
0.004
66/34
10.1
7.5




w/NaSilicate + NaOH
Eka RF 4031
















TABLE 42







pH ranges for Example 15 for neutral deinking












Pulping Liquor




Neutral Deinking pH range
pH
FF pH







Max pH
9.0
7.4



Min pH
7.6
7.2

















TABLE 43







Deinking Results for tests 1-6 (Example 15).


















Wet






Brightness
Brightness
Removal


Test
Reject
ERIC
ERIC
ERIC
Brightness
Brightness
Brightness
Difference
Difference
Efficiency


#
Wt.
Pulper
Flot
Hyper
Pulper
Flot
Hyper
vs. Conv
vs Sulfite
at Flot




















1
838
1010
331
217
40.6
48.9
48.8
NA
NA
67.3


2
644
931
330
154
41.2
49.4
51.3
0.5
NA
64.6


5
602
877
293
157
42.1
50.1
50.5
1.2
NA
66.6


4
453
1176
448
208
37.9
45.8
47.3
−3.1
NA
61.9


8
477
1062
381
167
40.3
47.9
49.1
−1.0
NA
64.2


3
907
825
258
135
43.3
50.8
52.1
1.9
NA
68.7


6
898
993
259
166
41.6
51.6
51.0
2.7
NA
73.9


7
762
962
265
154
41.8
51.3
49.9
2.3
NA
72.4


9
828
1023
310
179
41.3
49.5
49.3
0.6
NA
69.7









The ink fragmentation test conditions were within the range of conventional deinking except for the neutral deinking tests that included hydrogen peroxide. For ERIC values after flotation all of the neutral deinking conditions matched or out preformed conventional deinking. Except for cellulase all of the other neutral deinking conditions gave equal to better ink detachment.
All of the neutral deinking conditions were within 2 points of conventional deinking after flotation. Tests that included Xylanase, Xylanase/Lipase and peroxide had higher brightness than the sulfite based neutral deinking.
The hyperwash brightness after flotation was within two points of conventional deinking expect for tests that included sodium sulfite and lipase alone, cellulase alone, or amylase alone.
The tests that included lipase and hydrogen peroxide tended to have the highest levels of rejected material. However, the hydrogen peroxide tests were not been conducted at lower air injection rates.

## Claims

1. A method for removing ink from printed paper comprising the steps of:
(a) pulping printed paper at least 25 wt % of which is old newsprint at a consistency of at least about 3% to obtain a pulp slurry;
(b) treating the pulp slurry with an ink removing system, which system comprises:
(i) an enzyme combination consisting of lipase and xylanase, and
(ii) a non-ionic surfactant, in amounts effective to release ink from said pulp slurry,
wherein the lipase is present in an amount of at least about 0.001 wt % based on the dry content of the pulp slurry and the ratio of xylanase: lipase is at least about 1.2:1, wherein the total amount of enzyme is in the range from 0.0022 to less than 0.025 wt % based on the dry content of the pulp slurry; and

(c) separating the released ink from the pulp slurry in a deinking flotation stage to provide a deinked pulp slurry, wherein the treating step is carried out prior to the deinking flotation stage, and wherein the ink removal efficiency is at least about 50%.

2. A method according to claim 1, wherein the ratio of xylanase: lipase is at least about 1.5:1.

3. A method according to claim 2, wherein the ratio of xylanase: lipase is in the range of about 1.5:1 to about 2.5:1.

4. A method according to claim 2, wherein the non-ionic surfactant is chosen from fatty alcohol ethyoxylates (FAEO), propoxylates (FAPO) and combination thereof (FAEPO).

5. A method according to claim 4, wherein the ratio of (i): ii) is in the range of about 1:2 to about 1:4.

6. A method according to claim 1, wherein the ink removing system further comprises (iii) a soap.

7. A method according to claim 6, wherein the ink removing system further comprises (iv) an alkaline reagent.

8. A method according to claim 7, wherein the printed paper comprises ONP in an amount in the range of from about 40 wt % to about 95 wt %.

9. A method according to claim 7, wherein the soap is a fatty acid soap.

10. A method according to claim 7, wherein the alkaline reagent is sodium silicate.

11. A method according to claim 7, wherein the combination of enzymes (i) is a combination of lipase and xylanase; the non-ionic surfactant (ii) is chosen from fatty alcohol ethoxylates (FAEO), propoxylates (FAPO) and combinations thereof (FAEPO): the soap (iii) is a tallow fatty acid soap; and the alkaline reagent (iv) is sodium silicate.

12. A method according to claim 11, wherein the ratio of (i): (ii) is in the range of about 1:2 to 1:4.

13. A method according to claim 12, wherein (i) and (ii) are premixed to form an enzyme composition (v) and then adding (v) to the pulp slurry as a component of the ink removing system.

14. A method according to claim 13, wherein the enzyme composition (v) is added to the pulp slurry in an amount in the range of about 0.04 to about 0.5 wt %, the soap (iii) is added to the pulp slurry in an amount in the range of about 0.1 to about 1 wt %, and the alkaline reagent (iv) is added to the pulp slurry in an amount in the range of about 0.5 to about 2 wt %, all based on the solid content of the slurry.

15. A method according to claim 13, wherein the pH of the slurry is maintained in the range of about 6 to about 11.

16. A method according to claim 13, wherein the slurry is substantially free of sodium sulfite.

17. A method according to claim 13, wherein the slurry is substantially free of sodium hydroxide or, if added to the slurry, the sodium hydroxide is added in an amount less than 0.15 wt %, based on the weight of the slurry.

18. A method according to claim 13, wherein the slurry is substantially free of hydrogen peroxide.

19. A method according to claim 13, wherein the ink removal efficiency is at least 70%.

20. A method for removing ink from printed paper comprising the steps of:
(a) pulping printed paper at least 25 wt % of which is old newsprint at a consistency of at least about 3% to obtain a pulp slurry;
(b) treating the pulp slurry with an ink removing system, which system comprises:
(i) an enzyme combination consisting of lipase and xylanase, wherein the lipase is present in an amount of at least about 0.001 wt % based on the dry content of the pulp slurry, the ratio of xylanase to lipase is at least about 1.2:1, and the total amount of enzyme is in the range from 0.0022 to less than 0.025wt % based on the dry content of the pulp slurry; and
(ii) a nonionic surfactant, in amounts effective to release ink from said pulp slurry, and

(c) separating the released ink from the pulp slurry in a deinking flotation stage to provide a deinked pulp slurry, wherein the treating step is carried out prior to the deinking flotation stage, and wherein the ink removal efficiency is at least about 50%; and
wherein the pH of the deinking flotation stage is between 7.3 and 7.6.