HOME

TheInfoList



OR:

Paper is a thin sheet
material Material is a substance or mixture of substances that constitutes an object. Materials can be pure or impure, living or non-living matter. Materials can be classified on the basis of their physical and chemical properties, or on their geolo ...
produced by mechanically or chemically processing
cellulose Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell wa ...
fibre Fiber or fibre (from la, fibra, links=no) is a natural or artificial substance that is significantly longer than it is wide. Fibers are often used in the manufacture of other materials. The strongest engineering materials often incorporate ...
s derived from
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 lignin ...
, rags,
grasses Poaceae () or Gramineae () is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos and the grasses of natural grassland and species cultivated in lawns ...
or other vegetable sources in
water Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as ...
, draining the water through fine mesh leaving the fibre evenly distributed on the surface, followed by pressing and drying. Although paper was originally made in single sheets by hand, almost all is now made on large machines—some making reels 10 metres wide, running at 2,000 metres per minute and up to 600,000 tonnes a year. It is a versatile material with many uses, including
printing Printing is a process for mass reproducing text and images using a master form or template. The earliest non-paper products involving printing include cylinder seals and objects such as the Cyrus Cylinder and the Cylinders of Nabonidus. The ...
, painting, graphics, signage, design, packaging, decorating,
writing Writing is a medium of human communication which involves the representation of a language through a system of physically inscribed, mechanically transferred, or digitally represented symbols. Writing systems do not themselves constitute h ...
, and
cleaning Cleaning is the process of removing unwanted substances, such as dirt, infectious agents, and other impurities, from an object or environment. Cleaning is often performed for aesthetic, hygienic, functional, environmental, or safety purposes. ...
. It may also be used as filter paper, wallpaper, book endpaper, conservation paper, laminated worktops, toilet tissue, or currency and security paper, or in a number of industrial and construction processes. The papermaking process developed in east Asia, probably
China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's List of countries and dependencies by population, most populous country, with a Population of China, population exceeding 1.4 billion, slig ...
, at least as early as 105 CE, by the Han court
eunuch A eunuch ( ) is a male who has been castrated. Throughout history, castration often served a specific social function. The earliest records for intentional castration to produce eunuchs are from the Sumerian city of Lagash in the 2nd millenni ...
Cai Lun Cai Lun (; courtesy name: Jingzhong (); – 121 CE), formerly romanized as Ts'ai Lun, was a Chinese eunuch court official of the Eastern Han dynasty. He is traditionally regarded as the inventor of paper and the modern papermaking process ...
, although the earliest archaeological fragments of paper derive from the 2nd century BCE in China. The modern
pulp and paper industry The pulp and paper industry comprises companies that use wood as raw material and produce Pulp (paper), pulp, paper, paperboard and other cellulose-based products. Manufacturing process The pulp is fed to a paper machine where it is formed as ...
is global, with China leading its production and the United States following.


History

The oldest known archaeological fragments of the immediate precursor to modern paper date to the 2nd century BCE in
China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's List of countries and dependencies by population, most populous country, with a Population of China, population exceeding 1.4 billion, slig ...
. The pulp papermaking process is ascribed to
Cai Lun Cai Lun (; courtesy name: Jingzhong (); – 121 CE), formerly romanized as Ts'ai Lun, was a Chinese eunuch court official of the Eastern Han dynasty. He is traditionally regarded as the inventor of paper and the modern papermaking process ...
, a 2nd-century CE Han court
eunuch A eunuch ( ) is a male who has been castrated. Throughout history, castration often served a specific social function. The earliest records for intentional castration to produce eunuchs are from the Sumerian city of Lagash in the 2nd millenni ...
. It has been said that knowledge of papermaking was passed to the Islamic world after the
Battle of Talas The Battle of Talas or Battle of Artlakh (; ar, معركة نهر طلاس, translit=Maʿrakat nahr Ṭalās, Persian: Nabard-i Tarāz) was a military encounter and engagement between the Abbasid Caliphate along with its ally, the Tibetan Empi ...
in 751 CE when two Chinese papermakers were captured as prisoners. Although the veracity of this story is uncertain, paper started to be made in
Samarkand fa, سمرقند , native_name_lang = , settlement_type = City , image_skyline = , image_caption = Clockwise from the top:Registan square, Shah-i-Zinda necropolis, Bibi-Khanym Mosque, view inside Shah-i-Zinda, ...
soon after. In the 13th century, the knowledge and uses of paper spread from the
Middle East The Middle East ( ar, الشرق الأوسط, ISO 233: ) is a geopolitical region commonly encompassing Arabian Peninsula, Arabia (including the Arabian Peninsula and Bahrain), Anatolia, Asia Minor (Asian part of Turkey except Hatay Pro ...
to
medieval Europe In the history of Europe, the Middle Ages or medieval period lasted approximately from the late 5th to the late 15th centuries, similar to the post-classical period of global history. It began with the fall of the Western Roman Empire a ...
, where the first water-powered
paper mill A paper mill is a factory devoted to making paper from vegetable fibres such as wood pulp, old rags, and other ingredients. Prior to the invention and adoption of the Fourdrinier machine and other types of paper machine that use an endless belt ...
s were built. Because paper was introduced to the West through the city of Baghdad, it was first called ''bagdatikos''. In the 19th century, industrialization greatly reduced the cost of manufacturing paper. In 1844, the Canadian inventor Charles Fenerty and the German inventor Friedrich Gottlob Keller independently developed processes for pulping wood fibres.


Early sources of fibre

Before the industrialisation of paper production the most common fibre source was recycled fibres from used textiles, called rags. The rags were from
hemp Hemp, or industrial hemp, is a botanical class of '' Cannabis sativa'' cultivars grown specifically for industrial or medicinal use. It can be used to make a wide range of products. Along with bamboo, hemp is among the fastest growing plants ...
,
linen Linen () is a textile made from the fibers of the flax plant. Linen is very strong, absorbent, and dries faster than cotton. Because of these properties, linen is comfortable to wear in hot weather and is valued for use in garments. It also ...
and
cotton Cotton is a soft, fluffy staple fiber that grows in a boll, or protective case, around the seeds of the cotton plants of the genus '' Gossypium'' in the mallow family Malvaceae. The fiber is almost pure cellulose, and can contain minor pe ...
. A process for removing printing inks from recycled paper was invented by German jurist Justus Claproth in 1774. Today this method is called deinking. It was not until the introduction of
wood 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 ...
in 1843 that paper production was not dependent on recycled materials from ragpickers.


Etymology

The word ''paper'' is etymologically derived from
Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through ...
, which comes from the
Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...
(), the word for the plant.
Papyrus Papyrus ( ) is a material similar to thick paper that was used in ancient times as a writing surface. It was made from the pith of the papyrus plant, '' Cyperus papyrus'', a wetland sedge. ''Papyrus'' (plural: ''papyri'') can also refer to ...
is a thick, paper-like material produced from the pith of the ' plant, which was used in ancient Egypt and other
Mediterranean The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on ...
cultures for
writing Writing is a medium of human communication which involves the representation of a language through a system of physically inscribed, mechanically transferred, or digitally represented symbols. Writing systems do not themselves constitute h ...
before the introduction of paper. Although the word ''paper'' is etymologically derived from ''papyrus'', the two are produced very differently and the development of the first is distinct from the development of the second. Papyrus is a lamination of natural plant fibre, while paper is manufactured from fibres whose properties have been changed by maceration.


Papermaking


Chemical pulping

To make pulp from wood, a chemical pulping process separates
lignin Lignin is a class of complex organic polymers that form key structural materials in the support tissues of most plants. Lignins are particularly important in the formation of cell walls, especially in wood and bark, because they lend rigidity a ...
from
cellulose Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell wa ...
fibre. A cooking liquor is used to dissolve the
lignin Lignin is a class of complex organic polymers that form key structural materials in the support tissues of most plants. Lignins are particularly important in the formation of cell walls, especially in wood and bark, because they lend rigidity a ...
, which is then washed from the
cellulose Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell wa ...
; this preserves the length of the cellulose fibres. Paper made from chemical pulps are also known as
wood-free paper Wood-free paper is paper created exclusively from chemical pulp rather than mechanical pulp. Chemical pulp is normally made from pulpwood, but is not considered wood as most of the lignin is removed and separated from the cellulose fibers during p ...
s (not to be confused with
tree-free paper Tree-free paper or tree-free newsprint described an alternative to wood-pulp paper by its raw material composition. It is claimed to be more eco-friendly considering the product's entire life cycle. Sources of fiber for tree-free paper include ...
); this is because they do not contain lignin, which deteriorates over time. The pulp can also be bleached to produce white paper, but this consumes 5% of the fibres. Chemical pulping processes are not used to make paper made from cotton, which is already 90% cellulose. There are three main chemical pulping processes: the
sulfite process The sulfite process produces wood pulp that is almost pure cellulose fibers by treating wood chips with solutions of sulfite and bisulfite ions. These chemicals cleave the bonds between the cellulose and lignin components of the lignocellulose. A ...
dates back to the 1840s and was the dominant method before the second world war. The
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 chip ...
, invented in the 1870s and first used in the 1890s, is now the most commonly practised strategy; one of its advantages is the chemical reaction with lignin produces heat, which can be used to run a generator. Most pulping operations using the kraft process are net contributors to the electricity grid or use the electricity to run an adjacent paper mill. Another advantage is that this process recovers and reuses all inorganic chemical reagents. Soda pulping is another specialty process used to pulp
straw Straw is an agricultural byproduct consisting of the dry stalks of cereal plants after the grain and chaff have been removed. It makes up about half of the yield of cereal crops such as barley, oats, rice, rye and wheat. It has a number ...
s,
bagasse Bagasse ( ) is the dry pulpy fibrous material that remains after crushing sugarcane or sorghum stalks to extract their juice. It is used as a biofuel for the production of heat, energy, and electricity, and in the manufacture of pulp and building ...
and
hardwoods Hardwood is wood from dicot trees. These are usually found in broad-leaved temperate and tropical forests. In temperate and boreal latitudes they are mostly deciduous, but in tropics and subtropics mostly evergreen. Hardwood (which comes from ...
with high
silicate In chemistry, a silicate is any member of a family of polyatomic anions consisting of silicon and oxygen, usually with the general formula , where . The family includes orthosilicate (), metasilicate (), and pyrosilicate (, ). The name is a ...
content.


Mechanical pulping

There are two major mechanical pulps: thermomechanical pulp (TMP) and groundwood pulp (GW). In the TMP process, wood is chipped and then fed into steam-heated refiners, where the chips are squeezed and converted to fibres between two steel discs. In the groundwood process, debarked logs are fed into grinders where they are pressed against rotating stones to be made into fibres. Mechanical pulping does not remove the
lignin Lignin is a class of complex organic polymers that form key structural materials in the support tissues of most plants. Lignins are particularly important in the formation of cell walls, especially in wood and bark, because they lend rigidity a ...
, so the yield is very high, > 95%; however, lignin causes the paper thus produced to turn yellow and become brittle over time. Mechanical pulps have rather short fibres, thus producing weak paper. Although large amounts of
electrical energy Electrical energy is energy related to forces on electrically charged particles and the movement of electrically charged particles (often electrons in wires, but not always). This energy is supplied by the combination of electric current and elect ...
are required to produce mechanical pulp, it costs less than the chemical kind.


De-inked pulp

Paper recycling The recycling of paper is the process by which waste paper is turned into new paper products. It has a number of important benefits: It saves waste paper from occupying homes of people and producing methane as it breaks down. Because paper fib ...
processes can use either chemically or mechanically produced pulp; by mixing it with water and applying mechanical action the
hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-to ...
bonds in the paper can be broken and fibres separated again. Most recycled paper contains a proportion of virgin fibre for the sake of quality; generally speaking, de-inked pulp is of the same quality or lower than the collected paper it was made from. There are three main classifications of recycled fibre: * Mill broke or internal mill waste – This incorporates any substandard or grade-change paper made within the paper mill itself, which then goes back into the manufacturing system to be re-pulped back into paper. Such out-of-specification paper is not sold and is therefore often not classified as genuine reclaimed recycled fibre; however most paper mills have been reusing their own waste fibre for many years, long before recycling became popular. * Preconsumer waste – This is offcut and processing waste, such as guillotine trims and envelope blank waste; it is generated outside the paper mill and could potentially go to landfill, and is a genuine recycled fibre source; it includes de-inked preconsumer waste (recycled material that has been printed but did not reach its intended end use, such as waste from printers and unsold publications). * Postconsumer waste – This is fibre from paper that has been used for its intended end use and includes office waste, magazine papers and newsprint. As the vast majority of this material has been printed – either digitally or by more conventional means such as lithography or rotogravure – it will either be recycled as printed paper or go through a de-inking process first. Recycled papers can be made from 100% recycled materials or blended with virgin pulp, although they are (generally) not as strong nor as bright as papers made from the latter.


Additives

Besides the fibres, pulps may contain fillers such as
chalk Chalk is a soft, white, porous, sedimentary carbonate rock. It is a form of limestone composed of the mineral calcite and originally formed deep under the sea by the compression of microscopic plankton that had settled to the sea floor. C ...
or china clay, which improve its characteristics for printing or writing. Additives for
sizing Sizing or size is a substance that is applied to, or incorporated into, other materials—especially papers and textiles—to act as a protective filler or glaze. Sizing is used in papermaking and textile manufacturing to change the absorptio ...
purposes may be mixed with it or applied to the paper web later in the manufacturing process; the purpose of such sizing is to establish the correct level of surface absorbency to suit ink or paint.


Producing paper

The pulp is fed to a paper machine, where it is formed as a paper web and the water is removed from it by pressing and drying. Pressing the sheet removes the water by force. Once the water is forced from the sheet, a special kind of felt, which is not to be confused with the traditional one, is used to collect the water. When making paper by hand, a blotter sheet is used instead. Drying involves using air or heat to remove water from the paper sheets. In the earliest days of papermaking, this was done by hanging the sheets like laundry; in more modern times, various forms of heated drying mechanisms are used. On the paper machine, the most common is the steam-heated can dryer. These can reach temperatures above and are used in long sequences of more than forty cans where the heat produced by these can easily dry the paper to less than six percent moisture.


Finishing

The paper may then undergo
sizing Sizing or size is a substance that is applied to, or incorporated into, other materials—especially papers and textiles—to act as a protective filler or glaze. Sizing is used in papermaking and textile manufacturing to change the absorptio ...
to alter its physical properties for use in various applications. Paper at this point is ''uncoated''.
Coated paper Coated paper (also known as enamel paper, gloss paper, and thin paper) is paper that has been coated by a mixture of materials or a polymer to impart certain qualities to the paper, including weight, surface gloss, smoothness, or reduced ink absor ...
has a thin layer of material such as calcium carbonate or china clay applied to one or both sides in order to create a surface more suitable for high-resolution
halftone Halftone is the reprographic technique that simulates continuous-tone imagery through the use of dots, varying either in size or in spacing, thus generating a gradient-like effect.Campbell, Alastair. The Designer's Lexicon. ©2000 Chronicle, ...
screens. (Uncoated papers are rarely suitable for screens above 150 lpi.) Coated or uncoated papers may have their surfaces polished by
calender A calender is a series of hard pressure rollers used to finish or smooth a sheet of material such as paper, textiles, rubber, or plastics. Calender rolls are also used to form some types of plastic films and to apply coatings. Some cal ...
ing. Coated papers are divided into matte, semi-matte or silk, and gloss. Gloss papers give the highest
optical density Absorbance is defined as "the logarithm of the ratio of incident to transmitted radiant power through a sample (excluding the effects on cell walls)". Alternatively, for samples which scatter light, absorbance may be defined as "the negative lo ...
in the printed image. The paper is then fed onto reels if it is to be used on web printing presses, or cut into sheets for other printing processes or other purposes. The fibres in the paper basically run in the machine direction. Sheets are usually cut "long-grain", i.e. with the grain parallel to the longer dimension of the sheet. Continuous form paper (or continuous stationery) is cut to width with holes punched at the edges, and folded into stacks.


Paper grain

All paper produced by paper machines as the
Fourdrinier 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 Mac ...
are wove paper, i.e. the wire mesh that transports the web leaves a pattern that has the same density along the paper grain and across the grain. Textured finishes,
watermark A watermark is an identifying image or pattern in paper that appears as various shades of lightness/darkness when viewed by transmitted light (or when viewed by reflected light, atop a dark background), caused by thickness or density variations ...
s and wire patterns imitating hand-made ''laid'' paper can be created by the use of appropriate rollers in the later stages of the machine. Wove paper does not exhibit "laidlines", which are small regular lines left behind on paper when it was handmade in a mould made from rows of metal wires or bamboo. Laidlines are very close together. They run perpendicular to the "chainlines", which are further apart. Handmade paper similarly exhibits "deckle edges", or rough and feathery borders.


Applications

Paper can be produced with a wide variety of properties, depending on its intended use.


Published, written, or informational items

* For representing value:
paper money A banknote—also called a bill (North American English), paper money, or simply a note—is a type of negotiable promissory note, made by a bank or other licensed authority, payable to the bearer on demand. Banknotes were originally issued ...
,
bank note A banknote—also called a bill ( North American English), paper money, or simply a note—is a type of negotiable promissory note, made by a bank or other licensed authority, payable to the bearer on demand. Banknotes were originally issue ...
,
cheque A cheque, or check (American English; see spelling differences) is a document that orders a bank (or credit union) to pay a specific amount of money from a person's account to the person in whose name the cheque has been issued. The pers ...
,
security" \n\n\nsecurity.txt is a proposed standard for websites' security information that is meant to allow security researchers to easily report security vulnerabilities. The standard prescribes a text file called \"security.txt\" in the well known locat ...
(see ''
security paper Security paper is a paper used in security printing that incorporates features that can be used to identify or authenticate a document as original, e.g., watermarks or invisible fibres in paper, or features that demonstrate tamper evidence when fr ...
''),
voucher A voucher is a bond of the redeemable transaction type which is worth a certain monetary value and which may be spent only for specific reasons or on specific goods. Examples include housing, travel, and food vouchers. The term voucher is als ...
, ticket * For storing information:
book A book is a medium for recording information in the form of writing or images, typically composed of many pages (made of papyrus, parchment, vellum, or paper) bound together and protected by a cover. The technical term for this physical ...
,
notebook A notebook (also known as a notepad, writing pad, drawing pad, or legal pad) is a book or stack of paper pages that are often ruled and used for purposes such as note-taking, journaling or other writing, drawing, or scrapbooking. History ...
,
graph paper Graph paper, coordinate paper, grid paper, or squared paper is writing paper that is printed with fine lines making up a regular grid. The lines are often used as guides for plotting graphs of functions or experimental data and drawing curves ...
,
punched card A punched card (also punch card or punched-card) is a piece of stiff paper that holds digital data represented by the presence or absence of holes in predefined positions. Punched cards were once common in data processing applications or to di ...
,
photographic paper Photographic paper is a paper coated with a light-sensitive chemical formula, like photographic film, used for making photographic prints. When photographic paper is exposed to light, it captures a latent image that is then developed to form a ...
* For published materials, publications, and reading materials: books, newspapers, magazines, posters, pamphlets, maps, signs, labels, advertisements, billboards. * For individual use:
diary A diary is a written or audiovisual record with discrete entries arranged by date reporting on what has happened over the course of a day or other period. Diaries have traditionally been handwritten but are now also often digital. A personal ...
, notebooks, writing pads, memo pads journals, planners, note to remind oneself, etc.; for temporary personal use: scratch paper * For business and professional use: copier paper, ledger paper, typing paper, computer printer paper. Specialized paper for forms and documents such as invoices, receipts, tickets, vouchers, bills, contracts, official forms, agreements. * For
communication Communication (from la, communicare, meaning "to share" or "to be in relation with") is usually defined as the transmission of information. The term may also refer to the message communicated through such transmissions or the field of inqui ...
: between individuals and/or groups of people: letter, post cards, airmail, telegrams,
newsprint Newsprint is a low-cost, non-archival paper consisting mainly of wood pulp and most commonly used to print newspapers and other publications and advertising material. Invented in 1844 by Charles Fenerty of Nova Scotia, Canada, it usually has a ...
,
card stock Card stock, also called cover stock and pasteboard, is paper that is thicker and more durable than normal writing and printing paper, but thinner and more flexible than other forms of paperboard. Card stock is often used for business cards, ...
* For organizing and sending documents: envelopes, file folders, packaging, pocket folders, partition folders. * For artistic works and uses; drawing paper, pastels, water color paintings, sketch pads, charcoal drawings, * For special printed items using more elegant forms of paper; stationery, parchment,


Packaging and industrial uses

* For packaging:
corrugated box Corrugated box design is the process of matching design factors for corrugated fiberboard boxes with the functional physical, processing and end-use requirements. Packaging engineers work to meet the performance requirements of a box while control ...
, paper bag,
envelope An envelope is a common packaging item, usually made of thin, flat material. It is designed to contain a flat object, such as a letter or card. Traditional envelopes are made from sheets of paper cut to one of three shapes: a rhombus, a ...
, wrapping paper, paper string * For cleaning:
toilet paper Toilet paper (sometimes called toilet tissue or bathroom tissue) is a tissue paper product primarily used to clean the anus and surrounding anal region of feces after defecation, and to clean the perineal area and external genitalia of ur ...
,
paper towel A paper towel is an absorbent, disposable towel made from paper. In Britain, paper towels for kitchen use are also known as kitchen rolls, kitchen paper, or kitchen towels. For home use, paper towels are usually sold in a roll of Perforation, pe ...
s, facial tissue. * For food utensils and containers: wax paper, paper plates and paper cups, beverage cartons, tea bags, condiments, food packaging, coffee filters, cupcake cups. * For construction:
papier-mâché upright=1.3, Mardi Gras papier-mâché masks, Haiti upright=1.3, Papier-mâché Catrinas, traditional figures for day of the dead celebrations in Mexico Papier-mâché (, ; , literally "chewed paper") is a composite material consisting of p ...
,
origami paper Origami paper is used to fold ''origami'', the art of paper folding. The only real requirement of the folding medium is that it must be able to hold a crease, but should ideally also be thinner than regular paper for convenience when multiple fol ...
, paper planes, quilling, paper honeycomb,
sandpaper upright=1.35, Sheets of sandpaper with different grit sizes (40 (coarse), 80, 150, 240, 600 (fine)). Sandpaper and glasspaper are names used for a type of coated abrasive that consists of sheets of paper or cloth with abrasive material glued to ...
, used as a core material in
composite material A composite material (also called a composition material or shortened to composite, which is the common name) is a material which is produced from two or more constituent materials. These constituent materials have notably dissimilar chemical or ...
s,
paper engineering Paper engineering is a branch of engineering that deals with the usage of physical science (e.g. chemistry and physics) and life sciences (e.g. biology and biochemistry) in conjunction with mathematics as applied to the converting of raw materia ...
, construction paper, paper yarn, and paper clothing * For other uses:
emery paper Emery paper is a type of abrasive paper or sandpaper, that can be used to abrade (remove material from) surfaces or mechanically finish a surface. Operations include deburring, polishing, paint removal, corrosion removal, sizing, etc. This i ...
, blotting paper,
litmus paper Litmus is a water-soluble mixture of different dyes extracted from lichens. It is often absorbed onto filter paper to produce one of the oldest forms of pH indicator, used to test materials for acidity. It is a purple dye that is extracted ...
, universal indicator paper, paper chromatography,
electrical insulation paper Electrical insulation papers are paper types that are used as electrical insulation in many applications due to pure cellulose having outstanding electrical properties. Cellulose is a good insulator and is also polar, having a dielectric constan ...
(see also fishpaper), filter paper,
wallpaper Wallpaper is a material used in interior decoration to decorate the interior walls of domestic and public buildings. It is usually sold in rolls and is applied onto a wall using wallpaper paste. Wallpapers can come plain as "lining paper" (so ...
It is estimated that paper-based storage solutions captured 0.33% of the total in 1986 and only 0.007% in 2007, even though in absolute terms the world's capacity to store information on paper increased from 8.7 to 19.4 petabytes."The World's Technological Capacity to Store, Communicate, and Compute Information"
, especiall
Supporting online material
, Martin Hilbert and Priscila López (2011),
Science Science is a systematic endeavor that builds and organizes knowledge in the form of testable explanations and predictions about the universe. Science may be as old as the human species, and some of the earliest archeological evidence ...
, 332(6025), 60–65; free access to the article through here: martinhilbert.net/WorldInfoCapacity.html
It is estimated that in 1986 paper-based postal letters represented less than 0.05% of the world's telecommunication capacity, with sharply decreasing tendency after the massive introduction of digital technologies. Paper has a major role in the visual arts. It is used by itself to form two- and three-dimensional shapes and
collage Collage (, from the french: coller, "to glue" or "to stick together";) is a technique of art creation, primarily used in the visual arts, but in music too, by which art results from an Assemblage (art), assemblage of different forms, thus creat ...
s. It has also evolved to being a structural material used in furniture design.
Watercolor paper Watercolor paper or watercolour paper is paper or substrate onto which an artist applies watercolor paints, pigments or dyes. "The term “colour” is inappropriately given by common usage to material substances which convey a sense of colour t ...
has a long history of production and use.


Types, thickness and weight

The thickness of paper is often measured by caliper, which is typically given in thousandths of an inch in the United States and in micrometres (µm) in the rest of the world. Paper may be between thick. Paper is often characterized by weight. In the United States, the weight is the weight of a ream (bundle of 500 sheets) of varying "basic sizes" before the paper is cut into the size it is sold to end customers. For example, a ream of 20 lb, paper weighs 5 pounds because it has been cut from larger sheets into four pieces. In the United States, printing paper is generally 20 lb, 24 lb, 28 lb, or 32 lb at most. Cover stock is generally 68 lb, and 110 lb or more is considered
card stock Card stock, also called cover stock and pasteboard, is paper that is thicker and more durable than normal writing and printing paper, but thinner and more flexible than other forms of paperboard. Card stock is often used for business cards, ...
. In Europe and other regions using the
ISO 216 ISO 216 is an international standard for paper sizes, used around the world except in North America and parts of Latin America. The standard defines the "A", "B" and "C" series of paper sizes, including A4, the most commonly available paper si ...
paper-sizing system, the weight is expressed in grams per square metre (g/m2 or usually gsm) of the paper. Printing paper is generally between 60 gsm and 120 gsm. Anything heavier than 160 gsm is considered card. The weight of a ream therefore depends on the dimensions of the paper and its thickness. Most commercial paper sold in North America is cut to standard
paper size Paper size standards govern the size of sheets of paper used as writing paper, stationery, cards, and for some printed documents. The ISO 216 standard, which includes the commonly used A4 size, is the international standard for paper size. I ...
s based on
customary units United States customary units form a system of measurement units commonly used in the United States and U.S. territories since being standardized and adopted in 1832. The United States customary system (USCS or USC) developed from English uni ...
and is defined by the length and width of a sheet of paper. The ISO 216 system used in most other countries is based on the surface area of a sheet of paper, not on a sheet's width and length. It was first adopted in Germany in 1922 and generally spread as nations adopted the metric system. The largest standard size paper is A0 (A zero), measuring one square metre (approx. 1189 × 841 mm). A1 is half the size of a sheet of A0 (i.e., 594 mm × 841 mm), such that two sheets of A1 placed side by side are equal to one sheet of A0. A2 is half the size of a sheet of A1, and so forth. Common sizes used in the office and the home are A4 and A3 (A3 is the size of two A4 sheets). The
density Density (volumetric mass density or specific mass) is the substance's mass per unit of volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' can also be used. Mathematicall ...
of paper ranges from for tissue paper to for some specialty paper. Printing paper is about . Paper may be classified into seven categories: * ''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 paper Ingres paper is a type of drawing paper. It is a laid paper, laid finish paper of light to medium paper density, weight, and it is not as strong or as durable as Bristol paper. Laid finish refers to the imprint of regular screen pattern of a paperm ...
s, Japanese paper and tissues, all characterized by lack of grain direction. * ''Specialty papers'' including cigarette paper, toilet tissue, and other industrial papers. Some paper types include: * Bank paper *
Banana paper Banana paper is a type of paper created from banana plant bark or banana peel fibers. Banana paper has a lower density, higher stiffness, higher disposability, higher renewability, and higher tensile strength compared to traditional paper. These ...
*
Bond paper Bond paper is a high-quality durable writing paper similar to bank paper but having a weight greater than 50 g/m2. The most common weights are 60 g/m2 (16 lb), 75 g/m2 (20 lb) and 90 g/m2 (24 lb). The name comes from ...
* Book paper *
Coated paper Coated paper (also known as enamel paper, gloss paper, and thin paper) is paper that has been coated by a mixture of materials or a polymer to impart certain qualities to the paper, including weight, surface gloss, smoothness, or reduced ink absor ...
: glossy and matte surface * Construction paper/sugar paper *
Cotton paper Cotton paper, also known as rag paper or rag stock paper, is made using cotton linters (fine fibers which stick to the cotton seeds after processing) or cotton from used cloth (rags) as the primary material. Prior to the mid-19th century, cotto ...
*
Fish paper Vulcanized fibre or red fibre is a laminated plastic composed of only cellulose. The material is a tough, resilient, hornlike material that is lighter than aluminium, tougher than leather, and stiffer than most thermoplastics. The newer wood-lam ...
( vulcanized fibres for electrical insulation) * Inkjet paper * Kraft paper * Laid paper *
Leather paper Parchment is a writing material made from specially prepared untanned skins of animals—primarily sheep, calves, and goats. It has been used as a writing medium for over two millennia. Vellum is a finer quality parchment made from the skins ...
*
Mummy paper Mummy paper is paper that is claimed to be made from the linen wrappings and other fibers (e.g. papyrus) from Egyptian mummies imported to America circa 1855. The existence of this paper has not been conclusively confirmed, but it has been wi ...
* Oak tag paper *
Sandpaper upright=1.35, Sheets of sandpaper with different grit sizes (40 (coarse), 80, 150, 240, 600 (fine)). Sandpaper and glasspaper are names used for a type of coated abrasive that consists of sheets of paper or cloth with abrasive material glued to ...
*
Troublewit Troublewit is a specially pleated paper used for entertainment purposes. The paper is used to form various items, such as hats, fans and umbrellas by stage entertainers and illusionists. Its origins go back at least to the 17th Century. The metho ...
, specially pleated paper * Tyvek paper *
Wallpaper Wallpaper is a material used in interior decoration to decorate the interior walls of domestic and public buildings. It is usually sold in rolls and is applied onto a wall using wallpaper paste. Wallpapers can come plain as "lining paper" (so ...
*
Washi is traditional Japanese paper. The term is used to describe paper that uses local fiber, processed by hand and made in the traditional manner. ''Washi'' is made using fibers from the inner bark of the gampi tree, the mitsumata shrub (''E ...
* Waterproof paper *
Wax paper Waxed paper (also wax paper, waxpaper, or paraffin paper) is paper that has been made moisture-proof and grease-proof through the application of wax. The practice of oiling parchment or paper in order to make it semi-translucent or moisture-pro ...
*
Wove paper Wove paper is a type of paper first created centuries ago in the Orient, and subsequently introduced to England, Europe and the American colonies in the mid-eighteenth century. Hand-made wove paper was first produced by using a wooden mould that ...
*
Xuan paper Xuan paper (''xuanzhi'' ), or Shuen paper or rice paper, is a kind of paper originating in ancient China used for writing and painting. Xuan paper is renowned for being soft and fine textured, suitable for conveying the artistic expression of ...


Paper stability

Much of the early paper made from wood pulp contained significant amounts of
alum An alum () is a type of chemical compound, usually a hydrated double salt, double sulfate salt (chemistry), salt of aluminium with the general chemical formula, formula , where is a valence (chemistry), monovalent cation such as potassium or a ...
, a variety of
aluminium sulfate Aluminium sulfate is a salt with the chemical formula, formula aluminium, Al2sulfate, (SO4)3. It is soluble in water and is mainly used as a Coagulation (water treatment), coagulating agent (promoting particle collision by neutralizing charge) in ...
salt that is significantly
acidic In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a sequ ...
. Alum was added to paper to assist in
sizing Sizing or size is a substance that is applied to, or incorporated into, other materials—especially papers and textiles—to act as a protective filler or glaze. Sizing is used in papermaking and textile manufacturing to change the absorptio ...
, making it somewhat water resistant so that
inks Ink is a gel, sol, or solution that contains at least one colorant, such as a dye or pigment, and is used to color a surface to produce an image, text, or design. Ink is used for drawing or writing with a pen, brush, reed pen, or quill. Thicke ...
did not "run" or spread uncontrollably. Early papermakers did not realize that the alum they added liberally to cure almost every problem encountered in making their product would be eventually detrimental. The
cellulose Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to many thousands of β(1→4) linked D-glucose units. Cellulose is an important structural component of the primary cell wa ...
fibres that make up paper are
hydrolyzed Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile. Biological hydrolysis ...
by acid, and the presence of alum eventually degrades the fibres until the
acidic paper Acidic paper is paper that had some acidic substances used during the manufacture process. This type of paper, widely used since the mid-nineteenth century, turns yellow in a short time and becomes extremely brittle, which causes huge losses in lib ...
disintegrates in a process known as "
slow fire A slow fire is a term used in library and information science to describe paper embrittlement resulting from acid decay. The term is taken from the title of Terry Sanders's 1987 film ''Slow Fires: On the preservation of the human record.'' Solut ...
". Documents written on
rag paper Rag, rags, RAG or The Rag may refer to: Common uses * Rag, a piece of old cloth * Rags, tattered clothes * Rag (newspaper), a publication engaging in tabloid journalism * Rag paper, or cotton paper Arts and entertainment Film * ''Rags'' (1915 ...
are significantly more stable. The use of non-acidic additives to make paper is becoming more prevalent, and the stability of these papers is less of an issue. Paper made from
mechanical 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 ...
contains significant amounts of
lignin Lignin is a class of complex organic polymers that form key structural materials in the support tissues of most plants. Lignins are particularly important in the formation of cell walls, especially in wood and bark, because they lend rigidity a ...
, a major component in wood. In the presence of light and oxygen, lignin reacts to give yellow materials, which is why
newsprint Newsprint is a low-cost, non-archival paper consisting mainly of wood pulp and most commonly used to print newspapers and other publications and advertising material. Invented in 1844 by Charles Fenerty of Nova Scotia, Canada, it usually has a ...
and other mechanical paper yellows with age. Paper made from bleached kraft or
sulfite Sulfites or sulphites are compounds that contain the sulfite ion (or the sulfate(IV) ion, from its correct systematic name), . The sulfite ion is the conjugate base of bisulfite. Although its acid ( sulfurous acid) is elusive, its salts are wide ...
pulps does not contain significant amounts of lignin and is therefore better suited for books, documents and other applications where whiteness of the paper is essential. Paper made from wood pulp is not necessarily less durable than a rag paper. The aging behaviour of a paper is determined by its manufacture, not the original source of the fibres. Furthermore, tests sponsored by the Library of Congress prove that all paper is at risk of acid decay, because cellulose itself produces formic, acetic, lactic and oxalic acids. Mechanical pulping yields almost a tonne of pulp per tonne of dry wood used, which is why mechanical pulps are sometimes referred to as "high yield" pulps. With almost twice the yield as chemical pulping, mechanical pulps is often cheaper. Mass-market paperback books and newspapers tend to use mechanical papers. Book publishers tend to use
acid-free paper Acid-free paper is paper that, if infused in water, yields a neutral or basic (chemistry), basic pH (7 or slightly greater). It can be made from any cellulose fiber as long as the active acid pulp is eliminated during processing. It is also lign ...
, made from fully bleached chemical pulps for
hardback A hardcover, hard cover, or hardback (also known as hardbound, and sometimes as case-bound) book is one bound with rigid protective covers (typically of binder's board or heavy paperboard covered with buckram or other cloth, heavy paper, or occas ...
and trade paperback books.


Environmental impact

The production and use of paper has a number of adverse effects on the environment. Worldwide consumption of paper has risen by 400% in the past 40 years leading to increase in
deforestation Deforestation or forest clearance is the removal of a forest or stand of trees from land that is then converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban use. The most concentrated d ...
, with 35% of harvested trees being used for paper manufacture. Most paper companies also plant trees to help regrow forests. Logging of
old growth forest An old-growth forestalso termed primary forest, virgin forest, late seral forest, primeval forest, or first-growth forestis a forest that has attained great age without significant disturbance, and thereby exhibits unique ecological featur ...
s accounts for less than 10% of wood pulp, but is one of the most controversial issues. Paper waste accounts for up to 40% of total waste produced in the United States each year, which adds up to 71.6 million tons of paper waste per year in the United States alone. The average office worker in the US prints 31 pages every day. Americans also use in the order of 16 billion
paper cup A paper cup is a disposable cup made out of paper and often lined or coated with plastic or wax to prevent liquid from leaking out or soaking through the paper. It may be made of recycled paper and is widely used around the world. History Paper ...
s per year. Conventional bleaching of wood pulp using elemental chlorine produces and releases into the environment large amounts of chlorinated organic compounds, including chlorinated
dioxins Dioxin may refer to: * 1,2-Dioxin or 1,4-Dioxin, two unsaturated heterocyclic 6-membered rings where two carbon atoms have been replaced by oxygen atoms, giving the molecular formula C4H4O2 *Dibenzo-1,4-dioxin, the parent compound also known as ...
.Pdf
Dioxins are recognized as a persistent environmental pollutant, regulated internationally by the
Stockholm Convention on Persistent Organic Pollutants Stockholm Convention on Persistent Organic Pollutants is an international environmental treaty, signed on 22 May 2001 in Stockholm and effective from 17 May 2004, that aims to eliminate or restrict the production and use of persistent organic ...
. Dioxins are highly toxic, and health effects on humans include reproductive, developmental, immune and hormonal problems. They are known to be carcinogenic. Over 90% of human exposure is through food, primarily meat, dairy, fish and shellfish, as dioxins accumulate in the food chain in the fatty tissue of animals. The paper pulp and print industries emitted together about 1% of world
Greenhouse-gas emissions Greenhouse gas emissions from human activities strengthen the greenhouse effect, contributing to climate change. Most is carbon dioxide from burning fossil fuels: coal, oil, and natural gas. The largest emitters include coal in China and la ...
in 2010 and about 0.9% in 2012, but less than screens: digital technologies emitted approximately 4% of world
Greenhouse-gas emissions Greenhouse gas emissions from human activities strengthen the greenhouse effect, contributing to climate change. Most is carbon dioxide from burning fossil fuels: coal, oil, and natural gas. The largest emitters include coal in China and la ...
in the year 2019 and the number can be two times larger by 2025.


Future

Some manufacturers have started using a new, significantly more environmentally friendly alternative to expanded plastic packaging. Made out of paper, and known commercially as PaperFoam, the new packaging has mechanical properties very similar to those of some expanded plastic packaging, but is
biodegradable Biodegradation is the breakdown of organic matter by microorganisms, such as bacteria and fungi. It is generally assumed to be a natural process, which differentiates it from composting. Composting is a human-driven process in which biodegradati ...
and can also be recycled with ordinary paper. With increasing environmental concerns about synthetic coatings (such as
PFOA Perfluorooctanoic acid (PFOA; conjugate base perfluorooctanoate; also known colloquially as C8, for its 8 carbon chain structure) is a perfluorinated carboxylic acid produced and used worldwide as an industrial surfactant in chemical processes a ...
) and the higher prices of hydrocarbon based petrochemicals, there is a focus on
zein Zein is a class of prolamine protein found in maize (corn). It is usually manufactured as a powder from corn gluten meal. Zein is one of the best understood plant proteins.Momany, Frank A.; Sessa, David J.; Lawton, John C.; Selling, Gordon W.; H ...
(corn protein) as a coating for paper in high grease applications such as popcorn bags. Also, synthetics such as
Tyvek Tyvek () is a brand of synthetic flashspun high-density polyethylene fibers. The name "Tyvek" is a registered trademark of the American multinational chemical company DuPont, which discovered and commercialized Tyvek in the late 1950s and early ...
and Teslin have been introduced as printing media as a more durable material than paper.


See also


Citations


General references

* * * "Document Doubles" i
ARCHIVED – Introduction – Detecting the Truth. Fakes, Forgeries and Trickery – Library and Archives Canada
a virtual museum exhibition at Library and Archives Canada


Further reading

*
"Paper Brightness, Whiteness & Shade: Definitions and Differences"
by David Rogers (June 26, 2015)


External links


Technical Association of the Pulp and Paper Industry
(
TAPPI TAPPI is a registered not-for-profit, international Non-Governmental Organization of about 14,000 member engineers, scientists, managers, academics and others involved in the areas of pulp, and paper. In addition to pulp and paper, the TAPPI membe ...
) official website * The Arnold Yates Paper collection at
University of Maryland Libraries The University of Maryland Libraries is the largest university library in the Washington, D.C. - Baltimore area. The university's library system includes eight libraries: six are located on the College Park campus, while the Severn Library, an of ...

"How is paper made?"
at The
Straight Dope "The Straight Dope" was a question-and-answer newspaper column written under the pseudonym Cecil Adams. Contributions were made by multiple authors, and it was illustrated (also pseudonymously) by Slug Signorino. It was first published in 1973 i ...
, 22 November 2005
Thirteen-minute video on modern paper production system
from
Sappi Sappi Limited, originally incorporated as ''South African Pulp and Paper Industries Limited'' in 1936, is a South African pulp and paper company with global operations. Products and operation South African Pulp and Paper Industries Limite ...
{{Authority control Papermaking Chinese inventions