Pulp and Paper Industry PDF
Pulp and Paper Industry PDF
Pulp and Paper Industry PDF
Submitted by:
Sison, Bren A.
Valdez, Loisroi R.
Submitted to:
Instructor
TABLE OF CONTENTS
Introduction ______________________________________________________________ 3
Objectives ________________________________________________________________ 3
Brief History ______________________________________________________________ 4
Pulp _______________________________________________________________________ 5
Composition of Cellulose _______________________________________ 5
Kinds of Wood Pulp ______________________________________________ 9
Mechanical Pulping _____________________________________________ 12
Sulfite Pulping _________________________________________________ 17
Kraft Pulping ____________________________________________________ 29
Pulp Manufacturing Companies _________________________________ 39
Paper _____________________________________________________________________ 40
Types of Paper __________________________________________________ 40
Manufacturing Process of Paper _________________________________ 41
Paper Manufacturing Companies ________________________________ 46
Cardboard ________________________________________________________________ 47
Types of Cardboard _____________________________________________ 49
Manufacturing Process of Cardboard ____________________________ 51
Cardboard Manufacturing Companies ___________________________ 55
References _______________________________________________________________ 56
OBJECTIVES
General Objective
Specific Objective
The birth of paper took place under the Chinese Han Dynasty in AD
105 when a court ocial named Tsai Lun invented a papermaking process
which primarily used rags (textile waste) as the raw material with which to
make paper. These Chinese papermaking techniques spread across Asia,
Middle East and Europe in AD 610.
PULP
THE COMPOSITION OF CELLULOSE
Lignin Cellulose
Chemical Composition
- Biological function
Lignin fills the space in the cell wall between cellulose, hemicellulose and
pectin components, especially in xylem tracheids, vessel elements and sclereid
cells (Boerjan, Ralph, & Baucher, 2003). It is covalently linked to hemicellulose
and therefor cross-links different plant polysaccharides, conferring mechanical
strength to the cell wall and by extension the plant as a whole. It is particularly
abundant in compression wood but scarce in tension woods, which are types of
reaction wood.
Global production of lignin is around 1.1 M metric tons per year and is
used in a wide range of low volume, niche applications where the form but not
the quality is important.
- Biological function
Lignin fills the space in the cell wall between cellulose, hemicellulose and
pectin components, especially in xylem tracheids, vessel elements and sclereid
cells (Boerjan, Ralph, & Baucher, 2003). It is covalently linked to hemicellulose
and therefor cross-links different plant polysaccharides, conferring mechanical
strength to the cell wall and by extension the plant as a whole. It is particularly
abundant in compression wood but scarce in tension woods, which are types of
reaction wood.
- Ecological function
soil and expanding the capacity of moisture retention between flood and
drought conditions (Felder & Rousseau, 2005).
- Economic significance
Highly lignified wood is durable and therefore a good raw material for
many applications. It is also an excellent fuel, since lignin yields more energy
when burned than cellulose (Freudenberg & Nash, 1968). Mechanical or high
yield pulp used to make newsprint contains most of the lignin originally
present in the wood. This lignin is responsible for newsprints yellowing with
age. Lignin must be removed from the pulp before high-quality bleached paper
can be manufactured.
Alpha Cellulose
red. Examples of common paper fibers that are high in alpha cellulose include
cotton, flax, ramie and kozo. Alpha cellulose pulp can be created from wood
pulps using extended sulfite, or mercerized Kraft pulping method.
Hemicellulose
- Composition
mannose can be the most abundant sugar. Not only regular sugars can be
found in hemicellulose, but also their acidified form, for instance glucuronic
acid and galacturonic acid can be present (Stryer, Berg, John, & Gatto, 2015).
- Hemicellulose structure
Mechanical Pulp
Recycled Pulp
Recycled pulp is also called de-inked pulp (DIP). DIP is recycled paper
which has been processed by chemicals, thus removing printing inks and other
unwanted elements and freed the paper fibers. The process is called deinking.
Chemical Pulp
Sulfite pulp
The common sulfite process consists of the digestion of the
wood with a solution of magnesium, ammonium, or calcium
disulfide, with free sulfur dioxide present. Sulfite process involves
2 types of reaction (Smith, 2012):
1. The hydrolytic splitting of the cellulose and;
2. The reaction of the lignin with the bisulfate
a. Acid sulfite under acidic conditions, the object is
to solubilize lignin through the addition of
hydrophillicsulfonate groups (sulfonation)
b. Neutral sulfite most often neutral sulfite pulping is
used in association with mechanical pulping (Neutral Sulfite
Semi Chemical-NSSC). The purpose here is mainly to
soften the lignin.
C. Alkaline sulfite the goal is sulfonation and
fragmentation.
Sulfate pulp
Process for conversion of wood into wood pulp consisting of almost pure
cellulose fibers. It entails treatment of wood chips with liquor, which break the
bonds that link lignin to the cellulose through a cooking process.
Soda pulp
It is very similar to that sulfate pulp, both being alkaline processes. The
wood used is of the deciduous variety. The black liquor from the soda pulp
contains about 16% total solids and 4.5% total alkali. Most of the latter is
sodium carbonate, the remainder being free sodium hydroxide (Smith, 2012).
The insoluble impurities are allowed to settle out and the liquor is then
causticized by adding slaked lime prepared from the recovered CaCO 3.
MECHANICAL PULPING
Manufacturing Process of Mechanical Pulping
A debarker is a
machine used to
Debarking process
strip or removed
of removing barks
bark from logs
from the timber
before processing.
woods.
1. Debarker Machine
A chipper is a
machine used to
chip whole trees,
branches, debris,
mulch, and other
types of foliage.
Chipper range size
2. Chipper from smaller hand-
fed unit used in Chipping process
domestic and of turning debarked
agricultural woods into finer
applications to woodchops
mobile, whole-tree
chippers used to
chip slash and
residue in
commercial, logging,
and forestry
operations (Sappi
Tube, 2011).
It is used to filter
and separate
different sizes of raw
and crushed rock. It
can vary greatly in
its number of Filtering process
components and of separating large
3. Screener conveyors (Smith, wood chips from
2012). It is basically small wood chips.
a set of box frames
with varying sized
scree meshes
clamped and
tensioned in the
frame
7. Molder
SULFITE PULPING
Sulfite pulping dominated the industry from the late 1800s to the mid-
1900s, but the method used during this era was limited by the types of wood
which could be pulped and the pollution created by discharging untreated
waste cooking liquor into waterways. Newer methods have overcome many of
these problems, but sulfite pulping is now a small segment of the pulp market.
Although sulfite pulping usually uses acid digestion, both neutral and basic
variations exist.
The sulfite process produces wood pulp which is almost pure cellulose
fibers by using various salts of sulfurous acid to extract the lignin from wood
chips in large pressure vessels called digesters. The salts used in the pulping
process are either sulfites (SO32), or bisulfites (HSO3), depending on the pH.
The counter ion can be sodium (Na+), calcium (Ca2+), potassium (K+),
magnesium (Mg2+) or ammonium (NH4+).
HISTORY
The use of wood to make pulp for paper began with the development of
mechanical pulping in Germany by F.G. Keller in the 1840s. Chemical
processes quickly followed, first with J. Roths use of sulfurous acid to treat
wood, followed by Benjamin Chew Tilghmans US patent on the use of calcium
bisulfite, Ca(HSO3)2, to pulp wood in 1867. Almost a decade later in 1874 the
first commercial sulfite process|sulfite pulp mill was built in Sweden. It used
magnesium as the counter ion and was based on work by Carl Daniel Ekman.
Magnesium was the standard counter ion until calcium replaced it in the
1950s. Sulfite pulping was the dominant process for making wood pulp until it
was surpassed by the kraft process in the 1940s. Sulfite pulps now account for
less than 10% of the total chemical pulp production.
phenolic compounds
Cellulosic material
Spruce Hemlock tree
Balsam tree
Principal reaction in
RC:CR + Ca(HSO3)2 (RCHCRSO3)2Ca
digester
Time: 6-12 h;
Cooking conditions
Temp: 125-160C or higher;
Typical paper
products
sanitary tissue
APPLICATIONS
The 90-92 % cellulose content sulfite pulps are used mostly to make
textiles (like rayon) and cellophane. The 96-% cellulose content sulfate pulps
are used to make rayon yarn for industrial products such as tire cord, rayon
staple for high-quality fabrics, and various acetate and other specialty
products.
SULFITE PULPING
Unlike alkaline pulping, the purpose of sulfite pulping is not heavy lignin
fragmentation.
The common sulfite process consists of the digestion of the wood with a
solution of magnesium, ammonium, or calcium disulfide, with free sulfur
dioxide present.
i. Acid sulfite
Under acidic conditions, the object is to solubilize lignin
through the addition of hydrophillic sulfonate groups (sulfonation).
The pulping liquor for most sulfite mills is made by burning sulfur with
the correct amount of oxygen to give sulfur dioxide, which is then absorbed
into water to give sulfurous acid.
S + O2 SO2
Care must be taken to avoid the formation of sulfur trioxide since it gives
undesired sulfuric acid when it is dissolved in water.
2 SO2 + O2 2SO3
Pulping
R-O-R + H+ R+ + ROH
R+ + HSO3 R-SO3H
The sulfite process does not degrade lignin to the same extent that the
kraft process does and the lignosulfonates from the sulfite process are useful
byproducts.
MANUFACTURING PROCESS
Pulping
1. DEBARKING
It is the process of removing barks from the
timber woods. The present trend in the wood and
pulp industry is to debark and size the logs on the
site of the lumbering operations, then ship the pulp
chips and logs to their respective processing facilities
off-site. A debarker is a machine used to strip or
remove bark from logs before processing.
Debarker
2. CHIPPING
It is the process of turning
debarked woods into finer woodchips.
The objective is to fissure chips along
the grain, improving the penetration
of cooking liquor for efficient
delignification. A chipper is a machine
used to chip whole trees, branches,
debris, mulch and other types of
foliage. Chipper
3. FILTERING
It is the process of separating large wood
chips from small wood chips. The more
uniform chip and higher yields result in fewer
cooks for the same amount of pulp and may
also result in reduced energy consumption in
both the digester and the evaporator in
chemical pulping. A screen is used to filter and
separate different sizes of raw and different
sizes of raw and crushed rock. Screen
4. WASHING
It is the application of water
for getting the fiber. Pulp
washers are essential to fiber line
performance as the pulp needs to
be washed at almost all stages of
the process. The washing result
at one stage affects all the
subsequent stages.
Pulp washers
5. DIGESTION
It is the process of extracting lignin from wood chips. Pulp digester is used
for extracting lignin from wood chips in order to get only the fiber needed for
the production of pulp. Here, the wood chips with water is treated with the acid
sulfite liquor.
6. BLENDING
It is the process of stirring the mixture and commonly used together with
filtering while constantly spinning. Hydrapulpers, used mainly for handling
waste paper, are fitted with special devices for removing unwanted contraries
such as wire, plastic, paper clips, etc.
When the bales of wood pulp or waste paper arrive at the paper mill, they
are loaded onto a conveyor and passed into a circular tank containing water.
This has a very powerful agitator at the bottom which breaks up the bales into
small pieces.
7. FILTERING
It is the process of getting the pulp by passing a pair of filtering cloths and
belts through a system of rollers. Filters are used to get the pulp, which is then
transported to the rollers to flatten it for storage. The pulp product here is
commonly used for paper.
CHEMICAL RECOVERY
The spent cooking liquor from sulfite pulping is usually called brown
liquor, but the terms red liquor, thick liquor and sulfite liquor are also used
(compared to black liquor in the kraft process). Pulp washers, using
countercurrent flow, remove the spent cooking chemicals and degraded lignin
and hemicellulose. The extracted brown liquor is concentrated, in multiple
effect evaporators. The concentrated brown liquor can be burned in the
recovery boiler to generate steam and recover the inorganic chemicals for reuse
in the pulping process or it can be neutralized to recover the useful byproducts
of pulping. Recent developments in Chemrecs black liquor gasification process,
adapting the technology to use in the sulfite pulping process, could make
second generation biofuels production an alternative to the conventional
recovery boiler technology.
Calcium-based
Initially calcium was the preferred base because it was cheap and
convenient to use as it obtained as inexpensive calcium carbonate. However, no
recovery system is available for this base, so most calcium base mills either
have ceased operation or have converted to sodium, magnesium or ammonium
for which recovery systems are available. For calcium based liquor, the gas is
passed through towers packed with limestone with water flowing down through
the tower.
Ammonia-based
when burned. As long as aqueous NH3 remains low ion price, this process will
be attractive.
Magnesium-based
Sodium-based
screening
KRAFT PULPING
In Kraft pulping, white liquor, a water solution of sodium sulphide and
sodium hydroxide, is used under high temperature and pressure to chemically
dissolve the lignin that binds the cellulose fibres of the wood together. After the
wood chips are subjected to this digestion, the wood pulp is washed, screened
and dried to unbleached pulp or further delignified in an oxygen stage and
bleached in a bleach plant (Biermann, 1996). The inclusion of a bleaching step
depends upon the intended use of the product.
Water and quicklime are used to convert this smelt back to white liquor
in a causticising tank. The lime mud that precipitates from the tank is calcined
in a lime kiln to regenerate quicklime. Kraft recovery systems may also receive
spent liquor from neutral sulphite semi-chemical pulping mills (Smith, 2012).
Chemical Reaction:
Pressure: 100-124kPa
MANUFACTURING PROCESS
Debarking
Impregnation
In impregnation process, the chip from the chip bin is wetted and
preheated with steam. Cavities inside the fresh wood chips are partly filled with
liquid and air. The steam treatment of the steaming vessel causes the air to
expand and about 25% of the air to be expelled from the chips (Austin &
Austin, 1984).
In the impregnation tower the cooking liquor penetrates into the capillary
structure of the chips and low temperature chemical reactions with the wood
begin. The impregnation can be done before or after the chips enter the digester
and is normally done below 100 degrees Celsius (Sappi Tube, 2011). The
cooking liquor consists of a mixture of white liquor, water in chips, condensed
steam and weak black liquor. A good impregnation is important to get a
homogenous cook and low rejects (Smith, 2012).
The digestion is where the main part of the delignification takes place.
Here the chips are mixed with "white liquor" (a solution of sodium hydroxide
and sodium sulphide), heated to increase the reaction rate and then
disintegrated into fibres by 'blowing' - subjecting them to a sudden decrease in
pressure. This process is, like any chemical reaction, affected by time,
temperature and concentration of chemical reactants (Smith, 2012). Time and
temperature can be traded off against each other to a certain extent, but to
achieve reasonable cooking times it is necessary to have temperatures of about
150 - 165oC, so pressure cookers are used (Austin & Austin, 1984). However,
if the temperature is too high then the chips are delignified unevenly, so a
balance must be achieved.
There are two different cooking systems; batch and continuous. In batch
cooking, chips and white liquor are charged to a pressure vessel and are then
heated with steam to a set temperature for a set time. When the correct
delignification has been achieved, the cook is "blown" (the pressure is suddenly
released so that the cooked chips disintegrate into fibres). In the continuous
continuously to the top of a tall pressure vessel. The chips move down the
'digester' by gravity (as a plug) to be finally blown from the bottom of the vessel.
The cooking time cannot be varied in this case (it is set by the production rate)
and only the temperature and the chemical charge can be controlled.
Pulp Washing
The pulp from the blow tank is washed to remove the black liquor
from the pulp. There are several types of washers, including counter-
current vacuum, diffusion, rotary pressure, horizontal belt filters,
chemiwashers, wash press, and dilution/extraction (Sappi Tube, 2011).
The black liquor extracted from this process is diluted with wash water,
and so is called weak black liquor.
Bleaching
Oxygen Delignification
Final Bleaching
Evaporation
The black liquor from the pulp
washing contains 15-17% solids, and this
needs to be concentrated to about 60-70%
solids before it can be burnt in the
recovery furnace. "Spill liquors" may also
be recovered from various places in the
mill, and these dilute liquors supply
further amounts of water, which needs to
be evaporated (Sappi Tube, 2011).
To compensate for chemicals that are being lost in the pulp mill
cycle, sodium and sulphur chemicals are added to the black liquor before
combustion. Traditionally, sodium sulphate has been the normal 'make-
up' chemical, supplying both sodium and sulphur. However, modern
mills only lose small amounts of sulphur, and it has become necessary to
partially use 'sulphur free' make-up chemicals in form of caustic (NaOH)
or soda ash (Na2CO3).
C + O2 CO2 + heat
2C + O2 2CO + heat
CO + O2 CO2 + heat
2H2 + O2 2H2O + heat
Causticising
As well as dissolved
sodium based chemicals
(Na2CO3, Na2S and smaller
amounts of NaOH, Na2SO4 and
NaCl), the green liquor also
contains small amounts of
suspended solids, called
dregs. This material mostly
Clarified green liquor and burned lime (calcium oxide) are fed
continuously in metered amounts into a reaction vessel, called a
slaker. The calcium oxide reacts with the water in an exothermic
reaction to form calcium hydroxide or milk-oflime:
CaO + H2O Ca(OH)2 + heat
The slaker also contains a classifier section which removes
unreacted particles (grit). These are taken to landfill. After slaking, the
slurry is carried through a series of agitated tanks, which provide the
retention time for the causticising reaction as shown below:
Ca(OH)2 + Na2CO3 CaCO3 + 2NaOH
PAPER
TYPES OF PAPER
Printing papers of wide variety.
Wrapping papers for the protection of goods and merchandise. This
includes wax and kraft papers.
Writing paper suitable for stationery requirements. This includes ledger,
bank, and bond paper.
Blotting papers containing little or no size.
Drawing papers usually with rough surfaces used by artists and
designers, including cartridge paper.
Handmade papers including most decorative papers, Ingres
papers, Japanese paper and tissues, all characterized by lack of grain
direction.
Specialty papers including cigarette paper, toilet tissue, and other
industrial papers. (Johnson, 1978)
Tissue paper
Coated Papers
Specialty papers are often coated with wax or plastic materials to impart
special properties such as printability or resistance to fluids. Functional
coatings are especially important for
food products.
Specialty Papers
I. Equipment
Fourdrinier Machine
The very dilute stock from the foregoing operations, containing approximately
% fiber, is first sent through screens to the head box from which it flows
through a calibrated sluice onto a moving, endless wire screen. The pulp fibers
remain on the screen, while a great portion of the water drains through. As the
screen moves along, it has a sidewise shaking motion which serves to orient
some of the fibers and to give better felting action and more strength to the
sheet. While still on the screen, the paper passes over suction boxes to remove
water and under a dandy roll which smooths the top sheet. Rubeer deckle
straps along the sides of the screen serve to form the edges of the paper.
From the wire, the paper is transferred to the first felt blanket, which
carries it through a series of press rolls, where more water is removed and the
paper given a watermark if so desired. Leaving the first felt, the paper passes
through steel smoothing rolls and is picked up by the second felt, which carries
it through a series of drying rolls heated internally by steam. The paper enters
the rolls with a moisture content of 60 to 70% and leaves them 90 to 94% dry.
Sizing may be applied on the sheet at this point, in which case it must pass
through another series of drying rolls before entering the calendar stack, which
is a series of smooth, heavy, steel rolls which impart the final surface to the
paper. The resulting product, finished paper, is wound on the reel. The
enormous quantity of water used makes it necessary to recirculate as much of
- Fourdrinier machines
- Twin-wire formiers
- Multi-ply formers
By far the most common type of paper machine in use today is Fourdrinier. In
this former, stock is drained on a moving horizontal screen called a fabric. It
Multi-ply formers are used in the production of paperboard. The most common
type is cylinder formers. These consist of a series of screen covered cylinders,
each rotating in a vat of dilute paper stock. Web formation occurs on the
screen as a result of suction inside the cylinder which removes the filtrate.
1. The Headbox
Stock leaving the flow distributor
passes through a headbox before the
filtration process begins. The major
functions of the headbox are: to assure
uniform distribution of flow across the
paper machine; to provide velocity
control of the jet leaving the headbox
by the pressure in the headbox; and
break up of pulp flocs by turbulence
within the headbox. These functions
are achieved by causing the stock to flow through several rotating perforated
rolls within the headbox or, in modern headboxes, past stationary flow
elements. After passing through these turbulence-generating elements, the
stock is accelerated in a sharply converging orifice called a slice. On leaving the
slice, the stock becomes a free jet, which then impinges upon the forming
screen to begin the filtration process
of forming.
2. Forming Section
The Fourdrinier table of a paper
machine consists of foils, table rolls,
breast roll, couch roll, suction
boxes, wire rolls, and other parts.
The fabric on which the sheet of fibre is formed is a finely woven synthetic
fabric of strands made of specially fine drawn and filaments, woven into a
screen. Various types of weave are used to obtain maximum fabric life and to
reduce wire marking on the wet sheet.
The foils are located under the forming wire. In addition to supporting the wire,
the negative pressure created in the expanding nip on the underside of the
fabric, causing drainage of the water through the wire. Older paper machines
sometimes use table rolls for this purpose. However, most modern paper
machines now use foils.
After the foil section on the forming table, the moving fabric passes over a
series of vacuum boxes and then over a couch roll. Often, a dandy roll is
located on top of the forming fabric over the suction boxes. This is a light open
structured roll covered with wire cloth, resting lightly upon the surface of the
sheet. Its function is to flatten the top surface of the sheet and improve the
finish. A pattern on the dandy roll may leave translucent patterns on the wet
paper, in the form of names, insignia or designs. These are called watermarks.
The last roll over in the forming section is called the couch roll. It is a suction
roll to remove further water.
4. The Dryer
Paper leaves the press section and enters the dryer at a consistency of 40-45%.
The dryer causes further water removal by evaporation. A typical dryer section
consists of from 40 to 70 steam-heated dryer cylinders. The sheet is held in
intimate contact with the heated surfaces by
means of dryer felts.
5. Calendering
After the dryer, the paper web is passed
through a calender stack. This is a vertical
stack of solid iron rolls which impart
6. Reel
After the calender stack, the paper web is wound into a large roll at the end of
the paper machine, called a reel. The calendering and reeling operations are
the last part of the continuous paper machine.
7. Winder
When reels are wound to full size, the web is transferred to a new spool,
without machine shut down. The full reel is transferred by a crane to a winder
where it is unwound and slit into rolls based on customer specifications. In
newsprint mills, the rolls then goes to the wrapping station, and then into
storage.
8. Coating
High gloss papers are produced by coating the paper surface with a pigment-
binder compound, either on-machine or off-machine. The pigment consists of
mineral particles having platelet shapes, e.g. clays.
9. Supercalendering
Coated papers are passed through an off-line supercalender made up of hard
and soft rolls. These impart gloss to the coated surface.
10. Converting
This term describes further operations after papermaking to make products
from paper. Usually these are carried out in separate converting plants, but
some converting may be done in a paper mill, e.g. production and packaging of
sheets from continuous webs.
Water Removal
As is evident, much of the paper machine is devoted to water removal, taking
consistency from 0.5-1% to greater than 90%. The relative amount of water
removed in each section is shown in Figure 5. The cost of water removal at
CARDBOARD
INTRODUCTION
Cardboard is a generic term for a heavy-duty paper of various strengths,
ranging from a simple arrangement of a single thick sheet of paper to complex
configurations featuring multiple corrugated and uncorrugated layers. It is a
A material similar to thick, stiff paper, that is made of pressed paper pulp or pa
sted sheets of paper. It is used formaking cartons and signs
HISTORY
1817
The first commercial, but not corrugated, box out of paperboard was
made in England by Sir Malcolm Thornhill
1890
The Scottish-born Robert Gair invented the pre-
cut cardboard or paperboard box in 1890 flat pieces manufactured in
bulk that folded into boxes. Gair's invention came about as a result of an
accident: he was a Brooklyn printer and paper-bag maker during the
1870s, and one day, while he was printing an order of seed bags, a metal
ruler normally used to crease bags shifted in position and cut them. Gair
discovered that by cutting and creasing in one operation he could make
prefabricated paperboard boxes. Applying this idea to corrugated
boxboard was a straightforward development when the material became
available around the turn of the twentieth century
Kellogg Company
It is an American Multinational food manufacturing company established
in 1906. They were the first to utilize cardboard boxes as cereal cartons.
1871
Corrugated (also called pleated) paper was patented in England and used
as a liner for tall hats, but corrugated boxboard was not patented and
used as a shipping material until 20 December 1871. The patent was
issued to Albert Jones of New York City for single-sided (single-face)
corrugated board. Jones used the corrugated board for wrapping bottles
and glass lantern chimneys. The first machine for producing large
quantities of corrugated board was built in 1874 by G. Smyth, and in the
same year Oliver Long improved upon Jones's design by inventing
corrugated board with liner sheets on both sides. This was corrugated
cardboard as we know it today.
TYPES OF CARDBOARD
1. Card Stock
2. Paperboard
Paperboard is a thick paper-based material. While there is no rigid
differentiation between paper and paperboard, paperboard is
generally thicker than paper.
CLASSIFICATIONS OF PAPERBOARD
3. Corrugated fiberboard
Corrugated fiberboard is a material consisting of a fluted corrugated
sheet and one or two flat linerboards. It is made on "flute lamination
machines" or "corrugators" and is used in the manufacture
of shipping containers and corrugated boxes.
The corrugated medium and linerboard board both are made of
kraft containerboard, a paperboard material usually over 0.01 inches
(0.25 mm) thick. Corrugated fiberboard and paperboard are
sometimes called corrugated cardboard, although cardboard might be
any heavy paper-pulp based board.
MANUFACTURING PROCESS
Corrugating
Corrugator
1 2 3 2 1 5 6
transported to the other machines that will convert them into finished
containers. Skilled production workers use a computer terminal and
printer to prepare a job ticket for each stack of box blanks produced by
the corrugator. With the job ticket, workers can route the stack to the
right fabrication machines, called flexos (the name is short for
flexographic machine). A flexo is a wide, flat machine that processes box
blanks.
Printing dies and die-cutting patterns are prepared in a pattern shop on
large, flexible sheets of rubber or tin. The dies and patterns are loaded
onto the large rollers in the flexo, and the box blanks are automatically
fed through it. As each blank passes through the rollers of the flexo, it is
trimmed, printed, cut, scored, and, in a printer-folder-gluer, folded and
glued to form a box. From the flexo, the finished boxes are automatically
stacked and sent to a banding machine to be wrapped for shipping.
Other equipment in a corrugating plant includes stand-alone die-cutters,
die-cutters with print stations, and machines known as curtain coaters
that apply a wax coating to fruit, vegetable, and meat containers. Box
blanks requiring only simple, one-color printing and die-cutting can be
run through a stand-alone die-cutter, print station, and curtain coater to
produce water- or grease-resistant containers.
Folding Machine
Trimmer
REFERENCES
Austin, G., & Austin. (1984). Shreve's Chemical Process Industries. New York:
McGraw-Hill.
Boerjan, W., Ralph, & Baucher, M. (2003). Lignin Biosynthesis. Plant Biology,
519-549.
Smith, W. (2012). Pulp and Paper Industry in New Zealand. Industry in New
Zealand, 2-4.
Stryer, L., Berg, J., John, T., & Gatto, G. J. (2015). Biochemistry (8th Edition
ed.). W.H. Freeman Publishers.
Teschke, K. (2012). Pulp and Paper Industry. United Nations. Retrieved from
http://www.ilocis.org/documents/chpt72e.htm