Hemp Hurds as Paper-Making Material

Hemp Hurds as Paper-Making
Material, by

Lyster H. Dewey and Jason L. Merrill This eBook is for the use of
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Title: Hemp Hurds as Paper-Making Material United States
Department of Agriculture, Bulletin No. 404
Author: Lyster H. Dewey and Jason L. Merrill
Release Date: February 25, 2006 [EBook #17855]
Language: English
Character set encoding: ISO-8859-1
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HURDS AS PAPER-MAKING ***

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UNITED STATES DEPARTMENT OF AGRICULTURE
=BULLETIN No. 404=

Contribution from the Bureau of Plant Industry WM. A. TAYLOR,
Chief
[Illustration: USDA crests flanking bulletin banner]
Washington, D.C. PROFESSIONAL PAPER October 14, 1916
HEMP HURDS AS PAPER-MAKING MATERIAL.
By LYSTER H. DEWEY, Botanist in Charge of Fiber-Plant
Investigations, and JASON L. MERRILL, Paper-Plant Chemist,
Paper-Plant Investigations.
=CONTENTS.= Page. The production and handling of hemp hurds, by
Lyster H. Dewey:
What hemp hurds are 1 Pith, wood, and fiber 2 Character of hurds
affected by retting 2 Proportion of hurds to fiber and yield per acre 3
Hurds available from machine-broken hemp 3 Present uses of hemp
hurds 4 Present supplies of hurds available 5 Baling for shipment 5
Cost of baling 5 Summary 6
The manufacture of paper from hemp hurds, by Jason L. Merrill:
Introduction 7 Factors justifying an investigation of hemp hurds 8
Character of the material 11 Character of the tests 12 Operations
involved in a test 13 Description of tests 16 Comparison of the tests
and commercial practice 21 Physical tests of the papers produced 24
Conclusions 25
In preparing the report on the manufacture of paper from hemp hurds it
became evident that a short discussion of the agricultural aspects of this
material should be included in the publication. Such an article was
prepared, therefore, and the two reports are here presented together.
[NOTE.--This bulletin should be useful to all persons who are
interested in the economic phases of paper making, especially to print
and book paper manufacturers. It also should be of interest to scientific

investigators and chemists.]

=THE PRODUCTION AND HANDLING OF HEMP HURDS.=
By LYSTER H. DEWEY, Botanist in Charge of Fiber-Plant
Investigations.
=WHAT HEMP HURDS ARE.=
The woody inner portion of the hemp stalk, broken into pieces and
separated from the fiber in the processes of breaking and scutching, is
called hemp hurds. These hurds correspond to shives in flax, but are
much coarser and are usually softer in texture.
The hemp stalk grown in a broadcast crop for fiber production is from
one-eighth to three-eighths of an inch in diameter and from 4 to 10 feet
tall. The stalk is hollow, with a cylindrical woody shell, thick near the
base, where the stalk is nearly solid, and thinner above, where the
hollow is relatively wider.
In the process of breaking, the woody cylinder inside of the
fiber-bearing bark is broken into pieces one-half of an inch to 3 inches
long and usually split into numerous segments. The thicker lower
sections are split less than the thin-shelled upper ones, and they are
often left quite solid.
=PITH, WOOD, AND FIBER.=
The inner surface of the hurds usually bears a layer of pith, consisting
of thin-walled cells nearly spherical or angular, but not elongated. They
are more or less crushed and torn. They are probably of little value for
paper, but they constitute less than 1 per cent of the weight of the hurds.
The principal weight and bulk consist of slender elongated woody cells.
The outer surface is covered with fine secondary fibers composed of
slender elongated cells, tougher than those of the wood but finer and
shorter than those of the hemp fiber of commerce. No method has been
devised thus far which completely separates from the hurds all of the

long fiber. From 5 to 15 per cent of the weight of the hurds consists of
hemp fiber, in strands from 3 inches to 8 feet in length. Some
fragments of the bark, made up of short cubical cells, usually dark in
color, cling to the strands of fiber.
=CHARACTER OF HURDS AFFECTED BY RETTING.=
Nearly all of the hemp in the United States is dew retted. The stalks are
spread on the ground in swaths as grain is laid by the cradle. The action
of the weather, dew, and rain, aided by bacteria, dissolves and washes
out the green coloring matter (chlorophyll) and most of the gums,
leaving only the fibrous bark and the wood. The plants in this process
lose about 60 per cent of their green weight, or about 40