A shive is a small bundle of incompletely cooked
wood
Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of ligni ...
fibres in the
chemical pulp
Pulp is a lignocellulosic fibrous material prepared by chemically or mechanically separating cellulose fibers from wood, fiber crops, waste paper, or rags. Mixed with water and other chemical or plant-based additives, pulp is the major raw mate ...
used in
papermaking
Papermaking is the manufacture of paper and cardboard, which are used widely for printing, writing, and packaging, among many other purposes. Today almost all paper is made using industrial machinery, while handmade paper survives as a speciali ...
.
They are smaller than
knots
A knot is a fastening in rope or interwoven lines.
Knot may also refer to:
Places
* Knot, Nancowry, a village in India
Archaeology
* Knot of Isis (tyet), symbol of welfare/life.
* Minoan snake goddess figurines#Sacral knot
Arts, entertainmen ...
and are more difficult to separate from the pulp. Typically the content of shives in
kraft pulp
Kraft paper or kraft is paper or paperboard (cardboard) produced from chemical pulp produced in the kraft process.
Sack kraft paper (or just sack paper) is a porous kraft paper with high elasticity and high tear resistance, designed for packag ...
is 0.1 to 1.0%. An excess of shives is a sign of poor impregnation of the
wood chips
Woodchips are small- to medium-sized pieces of wood formed by cutting or chipping larger pieces of wood such as trees, branches, logging residues, stumps, roots, and wood waste.
Woodchips may be used as a biomass solid fuel and are raw mater ...
. Shives are separated from the pulp in the
screening
Screening may refer to:
* Screening cultures, a type a medical test that is done to find an infection
* Screening (economics), a strategy of combating adverse selection (includes sorting resumes to select employees)
* Screening (environmental), a s ...
and can be added back after refining. Even though shives are darker than rest of the pulp, they may pass unnoticed to the
paper machine
A paper machine (or paper-making machine) is an industrial machine which is used in the pulp and paper industry
to create paper in large quantities at high speed. Modern paper-making machines are based on the principles of the Fourdrinier Machi ...
because they are easily bleached. Shives in the paper machine can cause web breakage or other operational problems. They might also end as spots in the finished
paper
Paper is a thin sheet material produced by mechanically or chemically processing cellulose fibres derived from wood, Textile, rags, poaceae, grasses or other vegetable sources in water, draining the water through fine mesh leaving the fibre e ...
.
See also
*
Knot (papermaking) Knots are unwanted, large, dark aggregates of wood fibres when making chemical pulp.
Knots are incompletely cooked wood chips coming out of the digester. Their origin is often dense parts of branches, such as compression wood or timber knots &ndash ...
*
Kraft process
The kraft process (also known as kraft pulping or sulfate process) is a process for conversion of wood into wood pulp, which consists of almost pure cellulose fibres, the main component of paper. The kraft process involves treatment of wood ...
References
{{Paper
Papermaking