Nonwood Fiber Content Papers - Part 3:
Bleached Papers Physical Properties
By Robert W. Hurter, P. Eng., MBA, President, HurterConsult Incorporated, April 2002.

(requires Adobe Reader).
The data contained in the following table is from an excellent paper entitled "Industrial Experiences & Problems Involved In Stock Preparation & Papermaking Utilizing Non-Wood Fibrous Materials", written by D.K. Misra, Thessalian Pulp & Paper Industries Ltd., Larisa, Greece, and published in 1975 in the TAPPI Non-Wood Plant Fiber Pulping Progress Report No. 6.
This data was developed from tests on commercially produced paper and paperboards which were available at the time. Some of this data likely is a little outdated due to advancements in paper machine design such as improvements in Fourdrinier drainage and the development of twin wire paper machines and no-draw press sections, all of which allow for a high nonwood fiber fraction in the furnish. Nevertheless, this actual mill data still offers a valuable insight into the potential use of nonwood fibers in papermaking.
Unfortunately, since this paper was presented, no one has undertaken a similar ambitious project to determine the characteristics of currently available nonwood fiber content papers. With the renewed interest in nonwood fibers for papermaking in North America and Europe, perhaps the time has come for a research organization to undertake such a project.
The following table provides physical properties of bleached papers using different proportions of nonwood pulps. Even using pre-1975 technology, a few points to consider include:
 writing, printing, MG poster and lightweight papers produced with varying proportions of nonwood pulps are very comparable to those produced with 100% woodpulp
 writing and printing grades produced with 70% esparto pulp give the lowest hygro-expansion which indicates excellent dimensional stability
 tear factor is obviously poor in almost all grades of paper compared to the paper produced with 100% woodpulp, an inherent defect of most of the nonwood pulps
 using a statistical approach to the various properties of paper, writing and printing grades produced with a high proportion of nonwood pulps can be commercially acceptable
 paper produced with a high proportion of nonwood pulps have good sheet formation, printability and opacity.
With respect to the following table, the balance of the furnish in the nonwood content papers typically is bleached softwood kraft. It should be noted that the strength properties of the nonwood content papers could be increased by simply reducing the nonwood content and increasing the softwood kraft content.
Physical properties of bleached papers produced with different proportions of nonwood pulps
Paper Grade
|
Furnish
|
Basis
Weight
(g/m2)
|
Ash
(%)
|
Thickness
(microns)
|
Breaking
Length
(m)
|
Burst
Factor
|
Tear
Factor
|
Fold
No.
|
Cobb
(g/m2)
|
Porosity
(sec/100cc)
|
Opacity
(%)
|
Brightness
|
Denison
|
Finish
|
% Hygro-Expansion
|
Bagasse
|
MD
|
CD
|
Manifold
|
90% bagasse
|
35
|
1.2
|
55
|
2610
|
10.2
|
33.4
|
4
|
15
|
 |
66.0
|
 |
 |
MF
|
 |
 |
Printing & Writing
|
60/90% bagasse
|
50
|
10.1
|
81
|
2690
|
9.9
|
51.5
|
6
|
21
|
18
|
82.0
|
80.0
|
7
|
MF
|
0.7
|
2.5
|
Printing & Writing
|
60/90% bagasse
|
60
|
10.7
|
97
|
2980
|
12.5
|
49.3
|
12
|
27
|
30
|
84.0
|
77.6
|
9
|
MF
|
0.7
|
2.9
|
Printing & Writing
|
60/90% bagasse
|
70
|
10.3
|
107
|
3255
|
16.7
|
48.4
|
20
|
33
|
37
|
86.5
|
78.5
|
10
|
MF
|
0.6
|
2.8
|
Printing & Writing
|
60/90% bagasse
|
80
|
9.6
|
125
|
3340
|
17.7
|
50.8
|
22
|
24
|
52
|
89.0
|
80.0
|
10
|
MF
|
0.7
|
3.2
|
Printing & Writing
|
60/90% bagasse
|
100
|
7.5
|
160
|
3070
|
19.4
|
53.3
|
15
|
 |
 |
91.0
|
85.0
|
11
|
MF
|
0.1
|
2.8
|
Printing & Writing
|
60/90% bagasse
|
140
|
10.8
|
220
|
3170
|
22.2
|
58.7
|
53
|
 |
122
|
96.5
|
82.5
|
10
|
MF
|
0.4
|
2.7
|
Bamboo
|
Printing & Writing
|
60/90% bamboo
|
60
|
9.3
|
97
|
2600
|
11.6
|
59.6
|
8
|
19
|
7
|
88.0
|
74.0
|
7
|
MF
|
0.2
|
1.2
|
MG Poster
|
50% bamboo
|
30
|
2.0
|
60
|
4290
|
12.5
|
12.5
|
6
|
35
|
10
|
65.0
|
73.0
|
 |
MG
|
0.6
|
1.0
|
Reed
|
Writing
|
80% reed
|
63
|
11.1
|
90
|
2220
|
10.0
|
45.0
|
2
|
29
|
17
|
88.0
|
76.0
|
5
|
SC
|
0.1
|
1.8
|
Printing
|
80% reed
|
90
|
15.0
|
 |
3620
|
12.8
|
53.0
|
|
 |
 |
 |
 |
 |
 |
 |
 |
Straw
|
Printing & Writing
|
70/80% rice straw
|
50/55
|
9.5
|
84
|
3920
|
22.0
|
56.6
|
32
|
35
|
42
|
90.9
|
76.0
|
11
|
MF
|
0.3
|
2.6
|
Printing & Writing
|
82.5% rice straw
|
60
|
7.3
|
100
|
4000
|
20.0
|
58.3
|
17
|
42
|
66
|
94.0
|
81.0
|
12
|
MF
|
0.4
|
2.6
|
Printing & Writing
|
70/80% rice straw
|
70
|
10.6
|
106
|
3720
|
21.8
|
60.0
|
31
|
27
|
56
|
91.0
|
78.5
|
11
|
MF
|
0.5
|
2.4
|
Manifold
|
50/60% wheat straw
|
31
|
5.6
|
60
|
4900
|
20.4
|
68.0
|
55
|
26
|
46
|
60.5
|
91.0
|
 |
MF
|
 |
 |
Printing & Writing
|
75% wheat straw
|
50
|
10.6
|
63
|
4130
|
22.0
|
53.0
|
64
|
30
|
96
|
74.0
|
90.0
|
12
|
SC
|
0.2
|
3.2
|
Printing & Writing
|
75% wheat straw
|
60
|
13.7
|
70
|
4110
|
21.6
|
50.0
|
42
|
 |
122
|
80.5
|
87.0
|
11
|
SC
|
0.4
|
3.3
|
Printing & Writing
|
75% wheat straw
|
70
|
16.3
|
80
|
3620
|
20.0
|
47.0
|
47
|
35
|
194
|
83.5
|
90.0
|
10
|
SC
|
0.3
|
3.0
|
Printing & Writing
|
75% wheat straw
|
80
|
19.2
|
90
|
3581
|
18.7
|
42.7
|
35
|
47
|
215
|
88.0
|
89.0
|
9
|
SC
|
0.4
|
2.5
|
Printing & Writing
|
75% wheat straw
|
100
|
21.7
|
100
|
3470
|
18.0
|
44.6
|
38
|
 |
280
|
92.0
|
85.0
|
9
|
SC
|
0.3
|
2.9
|
Esparto
|
Printing & Writing
|
70% esparto
|
65
|
16.1
|
100
|
3325
|
17.1
|
82.0
|
22
|
22
|
23
|
86.0
|
80.5
|
11
|
MF
|
0.1
|
1.5
|
Printing & Writing
|
70% esparto
|
70
|
12.5
|
132
|
2860
|
13.0
|
65.0
|
20
|
22
|
10
|
86.0
|
80.6
|
 |
MF
|
0.1
|
1.3
|
Cotton
|
Writing
|
25% cotton
|
80
|
5.8
|
115
|
4040
|
23.6
|
68.4
|
24
|
19
|
84
|
82.0
|
91.0
|
+14
|
MF
|
 |
 |
For Comparison
|
Manifold
|
100% woodpulp
|
30
|
5.0
|
60
|
4770
|
21.0
|
66.0
|
60
|
18
|
56
|
51.0
|
84.0
|
 |
MF
|
 |
 |
Writing
|
100% woodpulp
|
60
|
10.7
|
80
|
4440
|
22.8
|
52.0
|
30
|
17
|
34
|
76.0
|
90.0
|
7
|
MF
|
0.2
|
1.6
|
Writing
|
100% woodpulp
|
70
|
9.5
|
100
|
3860
|
15.0
|
54.0
|
13
|
18
|
68
|
82.5
|
94.0
|
12
|
MF
|
0.2
|
1.8
|
Writing
|
100% woodpulp
|
80
|
8.5
|
106
|
3730
|
17.3
|
56.0
|
32
|
19
|
29
|
85.0
|
 |
11
|
MF
|
0.2
|
1.9
|
Offset Printing
|
100% woodpulp
|
80
|
5.6
|
105
|
4530
|
21.2
|
42.0
|
50
|
18
|
49
|
83.0
|
77.0
|
12
|
MF
|
0.2
|
1.5
|
Offset Printing
|
100% woodpulp
|
100
|
12.1
|
130
|
4040
|
21.0
|
44.0
|
58
|
18
|
83
|
90.0
|
84.0
|
21
|
MF
|
0.2
|
2.0
|
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