Nonwood Plant Fiber Uses in Papermaking
By Robert W. Hurter, P. Eng., MBA, President, HurterConsult Incorporated
Extracted from "Agricultural Residues", TAPPI 1997 Nonwood Fibers Short Course Notes, updated and expanded September 2001.
(requires Adobe Reader).Generally, nonwood plant fiber pulps can be grouped into two broad categories:
common nonwoods or hardwood substitutes such as cereal straws, sugarcane bagasse, bamboo (shorter fiber species), reeds and grasses, esparto, kenaf (whole stalk or core fiber), corn stalks, sorghum stalks etc.specialty nonwoods or softwood substitutes such as cotton staple and linters; flax, hemp and kenaf bast fibers; sisal; abaca; bamboo (longer fiber species); hesperaloe etc.As with wood, there are differing chemical and physical properties within the two groups depending on the nonwood fiber raw material (see Nonwood Plant Fiber Characteristics).
The current uses of nonwood pulps include virtually every grade of paper produced including:
printing and writing paperslinerboardcorrugating mediumnewsprinttissuespecialty papers Typically, common nonwood pulps or hardwood substitutes are produced in integrated pulp and paper mills, and softwood kraft or sulfite pulp is added to provide the strength requirements to the paper. However, specialty nonwood pulp may be used instead of softwood kraft or sulfite pulp thus producing a 100% nonwood paper. And, in some cases, wastepaper pulp may be blended in the furnish. The nonwood portion of the furnish typically varies from 20 to 90% and can be even up to 100% depending on the paper grade and required quality. The possible combinations are endless and can be adjusted to meet market requirements.
Furthermore, it is possible to add small quantities (up to 20 - 30%) of common nonwood pulps to primarily woodpulp-based papers without impairing paper properties or paper machine runnability. This provides wood-based mills which are hardwood deficient but located within a region with available nonwood fiber resources such as cereal straw or corn stalks with the option of adding-on a nonwood pulping line to supplement their fiber requirements.
Typically, the specialty nonwoods have physical properties superior to softwoods and can be used in lower amounts in the furnish when used as a softwood substitute. Specialty papers such as currency, cigarette papers, tea bags, dialectric paper etc. may be made from a furnish of 100% nonwood specialty pulps. Specialty pulps also may be used in combination with woodpulp to produce lightweight and ultra-lightweight printing and writing papers.
Combinations of common and specialty nonwood pulps will permit the production of virtually any grade of paper to meet any quality requirements demanded in the global market. Adding possible combinations which include wood pulp, nonwood pulp and recycled wastepaper pulp increases the possibilities for developing paper with specific sheet properties designed to meet specific customers needs.
The following table provides some uses for nonwood pulps in papermaking. It is by no means complete as many nonwood plant raw materials could be added to the table as well as products listed for each of the nonwood plant fiber raw materials identified. Rather this table provides an indication of the many possibilities which are available for the use of nonwood plant fibers in papermaking. When reviewing this table, please note:
The nonwood fiber in the furnish is chemical pulp unless noted otherwise.In all cases for the balance of furnish, “kraft “ or “sulfite” means kraft or sulfite chemical pulp made from softwoods, and bleached, semi-bleached or unbleached depending on the type of paper or paperboard. The term “woodpulp” is used when either softwood kraft or softwood sulfite chemical pulp or a mixture of the two may be used. In some cases, where the nonwood fiber content of the furnish is low or the nonwood fiber is very strong, part of the furnish may be hardwood kraft together with softwood kraft and/or softwood sulfite.Nonwood Fiber
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Type of Paper / Paperboard
|
Furnish
|
|
Named Nonwood Fiber
|
Balance of Furnish
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Abaca
|
currency
|
20 - 50%
|
cotton pulp
|
filter paper
|
10 - 80%
|
cotton pulp or woodpulp
|
|
high-grade book & writing
|
10 - 100%
|
cotton pulp or woodpulp
|
|
high-grade bond & ledger
|
10 - 100%
|
cotton pulp or woodpulp
|
|
linerboard
|
10 - 30%
|
bagasse or straw pulp
|
|
nonwovens
|
10 - 50%
|
synthetic fiber
|
|
sausage skins
|
90 - 100%
|
flax or sisal pulp
|
|
security paper
|
20 - 100%
|
cotton pulp or woodpulp
|
|
tea bags
|
90 - 100%
|
flax pulp
|
|
wrapping & bag
|
10 - 30%
|
bagasse or straw pulp
|
|
Bagasse
|
bristol board
|
60 - 100%
|
woodpulp
|
corrugating medium
|
60 - 90%
|
wastepaper
|
|
duplex & triplex board
|
50 - 80%
|
woodpulp
|
|
glassine & greaseproof
|
40 - 90%
|
sulfite pulp
|
|
linerboard
|
50 - 80%
|
kraft pulp
|
|
multiwall sack
(requires Clupak)
|
30 - 80%
|
kraft pulp
|
|
newsprint substitute
|
70 - 90%
(chemimechanical)
|
kraft pulp
|
|
newsprint substitute
|
70 - 80%
(mechanical)
|
kraft pulp
|
|
newsprint substitute
|
50 - 65%
(chemimechanical)
|
20% woodpulp, balance bleached bagasse
|
|
printing & writing - mechanical
|
30 - 60%
(chemimechanical)
|
20 - 30% woodpulp, balance groundwood
|
|
printing & writing - woodfree
|
20 - 100%
|
woodpulp
|
|
tissue
|
60 - 90%
|
woodpulp
|
|
wrapping & bag papers
|
50 - 85%
|
kraft pulp
|
|
Bamboo
|
bristol board
|
50 - 100%
|
woodpulp and/or bagasse pulp
|
duplex & triplex board
|
30 - 80%
|
woodpulp and/or straw or bagasse pulp
|
|
linerboard
|
60 - 100%
|
kraft pulp
|
|
multiwall sack
|
80 - 100%
|
kraft pulp
|
|
newsprint substitute
|
50 - 70%
|
groundwood pulp
|
|
printing & writing - mechanical
|
40 - 60%
|
groundwood
|
|
printing & writing - woodfree
|
70 - 100%
|
woodpulp and/or straw or bagasse pulp
|
|
wrapping & bag papers
|
80 - 100%
|
kraft pulp
|
|
Cotton
|
currency & security paper
|
50 - 100%
|
flax
|
high-grade book & writing
|
20 - 100%
|
woodpulp
|
|
high-grade bond & ledger
|
20 - 100%
|
woodpulp
|
|
Ekara, Knagra & Nal grass mixed
|
printing & writing - woodfree
|
50 - 70%
|
woodpulp
|
wrapping
|
40 - 60%
|
woodpulp
|
|
Esparto
|
blotting paper
|
50 - 80%
|
woodpulp
|
cigarette burning tube
|
20 - 30%
|
flax pulp or woodpulp
|
|
cigarette filter tip paper
|
50 - 70%
|
flaw pulp or kraft pulp
|
|
lightweight papers
|
50 - 70%
|
woodpulp
|
|
printing & writing - woodfree
|
30 - 100%
|
woodpulp
|
|
Flax
(bast fiber)
|
cigarette burning tube
|
20 - 100%
|
woodpulp
|
currency
|
50 - 80%
|
cotton pulp or woodpulp
|
|
lightweight printing & writing
|
20 - 80%
|
cotton pulp or woodpulp
|
|
ultra lightweight paper (bible)
|
50 - 100%
|
cotton pulp or woodpulp
|
|
writing & book
|
20 - 60%
|
cotton pulp or woodpulp
|
|
security paper
|
50 - 80%
|
cotton pulp or woodpulp
|
|
Hemp, true
(bast fiber)
|
cigarette paper
|
50 - 100%
|
woodpulp, bagasse, straw, kenaf bast or jute bast pulp
|
condenser paper
|
20 - 60%
|
woodpulp, flax or cotton pulp
|
|
currency
|
50 - 80%
|
flax, cotton or woodpulp
|
|
lightweight printing & writing
|
20 - 80
|
woodpulp, flax or cotton pulp
|
|
security paper
|
50 - 80%
|
flax, cotton or woodpulp
|
|
Jute
(bast fiber)
|
cigarette paper
|
30 - 50%
|
hemp pulp
|
printing & writing - woodfree
|
20 - 80%
|
woodpulp
|
|
tag paper
|
40 - 80%
|
woodpulp or bamboo pulp
|
|
wrapping & bag paper
|
40 - 80%
|
woodpulp or bamboo pulp
|
|
Kenaf
(bast fiber)
|
bleached paperboard
|
50 - 100%
|
woodpulp, bagasse or straw pulp
|
cigarette paper
|
50 - 100%
|
woodpulp, flax, hemp or abaca pulp
|
|
lightweight specialty papers
|
50 - 100%
|
woodpulp, flax, hemp or abaca pulp
|
|
linerboard
|
50 - 100%
|
kraft, bagasse, straw or wastepaper pulp
|
|
multiwall sack
|
50 - 100%
|
kraft, bagasse or straw pulp
|
|
newsprint
|
20 - 30%
|
wood, bagasse or kenaf core mechanical pulp
|
|
printing & writing - mechanical
|
20 - 50%
|
20 - 40% woodpulp, balance mechanical pulp
|
|
printing & writing - woodfree
|
20 - 100%
|
woodpulp, bagasse, straw, reeds or bamboo pulp
|
|
tissue
|
60 - 90%
|
woodpulp, bagasse or straw pulp
|
|
Kenaf
(whole stalk)
|
bleached paperboard
|
40 - 50%
|
woodpulp
|
corrugating medium
|
50 - 100%
|
wastepaper
|
|
linerboard
|
40 - 50%
|
kraft pulp and wastepaper pulp
|
|
multiwall sack
|
20 - 40%
|
kraft pulp
|
|
newsprint
|
80 - 90%
(chemimechanical)
|
woodpulp
|
|
printing & writing - mechanical
|
20 - 50%
(chemimechanical)
|
woodpulp
|
|
printing & writing - woodfree
|
20 - 80%
|
woodpulp
|
|
tissue
|
50 - 60%
|
woodpulp
|
|
Phragmites communis reeds
|
corrugating medium
|
60 - 90%
|
wastepaper
|
duplex & triplex board
|
30 - 80%
|
woodpulp
|
|
linerboard
|
50 - 70%
|
kraft pulp
|
|
printing & writing - mechanical
|
20 - 50%
|
20 - 40% woodpulp, balance mechanical pulp
|
|
printing & writing - woodfree
|
20 - 90%
|
woodpulp
|
|
wrapping - “B” grade
|
50 - 60%
|
kraft pulp
|
|
Sisal
|
currency
|
20 - 50%
|
cotton pulp
|
filter paper
|
10 - 80%
|
cotton pulp or woodpulp
|
|
high-grade book & writing
|
20 - 100%
|
abaca, cotton or woodpulp
|
|
high-grade bond & ledger
|
20 - 100%
|
abaca, cotton or woodpulp
|
|
lightweight bond & ledger
|
10 - 80%
|
abaca, cotton or woodpulp
|
|
nonwovens
|
10 - 50%
|
synthetic fiber
|
|
printing & writing - woodfree
|
20 - 100%
|
woodpulp
|
|
publication grades
|
15 - 20%
|
10 - 15% woodpulp, balance groundwood
|
|
sausage skins
|
90 - 100%
|
abaca or flax pulp
|
|
security paper
|
20 - 100%
|
cotton pulp or woodpulp
|
|
tea bags
|
50 - 80%
|
abaca or flax pulp
|
|
Straw
(cereal & rice)
|
corrugating medium
|
60 - 90%
|
wastepaper
|
duplex & triplex board
|
40 - 80%
|
woodpulp
|
|
glassine & greaseproof
|
40 - 90%
|
sulfite pulp
|
|
printing & writing - woodfree
|
20 - 90%
|
woodpulp
|
|
printing & writing - mechanical
|
30 - 50%
|
15 - 30% woodpulp, balance groundwood
|
|
strawboard
|
80 - 100%
|
wastepaper
|
|
wrapping paper - “B” grade
|
50 - 60%
|
wastepaper and/or woodpulp
|
|
Sources:
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1. Hurter, Robert W., “Agricultural Residues”, TAPPI 1997 Nonwood Fibers Short Course.
2. Hurter, A.M., “Utilization of Annual Plants and Agricultural Residues for the Production of Pulp and Paper”, Nonwood Plant Fiber Pulping Progress Report #19, TAPPI Press, pp. 49-70.
3. Rangamannar, Goda, “Conventional Paper Grades & Pulp Properties”, TAPPI 1997 Nonwood Fibers Short Course.
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