Shopping on line can be easy, simple and save you lots of money. It can also take a lot of your time, frustrate you, and result in unwanted purchases. Now the same can be said for regular high street shopping, but with the vast opportunity presented by the Internet it will pay you to spend a few minutes reading this and understanding how to better optimize your Paper shopping experience:
1. Compare - without doubt the biggest advantage that the Paper offers shoppers today is the ability to compare thousands of Paper at a time. This is a great thing, but not necessarily all the time! Too much can be daunting at times so take advantage of the great comparison sites and where possible let them do the hard work for you.
2. Research - if it has been said it will be on the internet. Ignorance is no longer a justifiable reason for buying the wrong thing. Take the time to research in detail everything that you could possible want to know about
3. Testimonials - don't know anybody that has bought a Paper? Wrong! If the Paper is good the internet will let you know. Use the Internet as a friend and get testimonials before you buy.
4. Questions - Got a question about Paper then search the Forums, FAQ's, Blogs etc. Don't be afraid to ask .....
5. Reputation - Never heard of the company selling Paper? Don't worry, no reason why you should know every company in the world, but you know someone that does! Use the internet to find out what people are saying about Paper and build up a picture of their reputation for sales, returns, customer service, delivery etc.
6. Returns - still worried that even after all of the above your Paper wont be what you want? Check out the returns policy. There is so much competition now that someone, somewhere is bound to offer the terms that you are comfortable with.
7. Feedback - happy with your Paper then let people know, after all you are depending on others people input in your buying decision, so why not give a little back.
8. Security - check for the yellow padlock on the Paper site before you buy, and the s after http:/ /i.e. https:// = a secure site
9. Contact - got a question about Paper, or want to leave a comment then check out the sites contact page. Reputable companies have them and respond.
10. Payment - ready to pay for your Paper, then use your credit card or PayPal! Be aware of companies that don't accept them, there may be genuine reasons but given the huge amount of choice you have when buying online there is no reason at all not to buy via credit card or PayPal.
Paper is thin material used for writing upon, printing upon or packaging, produced by the amalgamation of
fibres, typically vegetable fibers composed of cellulose, which are subsequently held together by
hydrogen bonding. While the fibres used are usually natural in origin, a wide variety of synthetic fibres, such as polypropylene and polyethylene, may be incorporated into paper as a way of imparting desirable physical properties. The most common source of these kinds of fibres is
wood pulp from
pulpwood trees. fibre crop materials such as cotton,
hemp, linen, and
rice are also used.
Papyrus and parchment
The word
paper derives from the Greek term for the ancient
Egyptian writing material called papyrus, which was formed from beaten strips of
Cyperus papyrus. Papyrus was produced as early as 3000 BC in Egypt, and sold to ancient
Greece and
Rome. The establishment of the Library of Alexandria in the 3rd century BC put a drain on the supply of papyrus. As a result, according to the Roman historian
Pliny the Elder (Natural History records, xiii.21), parchment was invented under the patronage of Eumenes of Pergamum to build his rival library at Pergamum. Outside of Egypt, parchment or vellum, made of processed
sheepskin or
calfskin, replaced papyrus as the papyrus plant requires subtropical conditions to grow.
Early papermaking in China
Paper is considered to be one of the
Four Great Inventions of Ancient China, as the first standard papermaking process was developed in China during the early 2nd century. During the
Shang Dynasty (
1600 BC-1050 BC) and
Zhou Dynasty (
1050 BC-256 BC) dynasties of ancient China, documents were ordinarily written on bone or bamboo (on tablets or on bamboo strips sewn and rolled together into scrolls), making them very heavy and awkward to transport. The light material of silk was sometimes used, but was normally too expensive to consider. Indeed, most of the above materials were rare and costly. While the
Han Dynasty China court official
Cai Lun is widely regarded to have first invented the modern method of papermaking (inspired from wasps and bees) from wood pulp in 105 AD, the discovery of specimens bearing written
Chinese characters in 2006 at north-west China's
Gansu province suggest that paper was in use by the ancient Chinese military more than 100 years before Cai in 8 BC. Archeologically however, true paper without writing has been excavated in China dating to the reign of Emperor Wu of Han from the
2nd century BC, used for purposes of wrapping or padding protection for delicate bronze mirrors.Needham, Volume 4, 122. It was also used for safety, such as the padding of poisonous 'medicine' as mentioned in the official history of the period. Although paper used for writing became widespread by the 3rd century,Needham, Volume 4, 1. paper continued to be used for wrapping (and other) purposes.
), the
Diamond Sutra of AD 868, shows the widespread availability and practicality of paper in China.Toilet paper was used in China by at least the 6th century AD.Needham, Volume 4, 123. In AD 589, the Chinese scholar-official Yan Zhitui (
531-
591 AD) once wrote: "Paper on which there are quotations or commentaries from
Five Classics or the names of sages, I dare not use for toilet purposes". An Arab traveler to China once wrote of the curious Chinese tradition of toilet paper in AD 851, writing: "They (the Chinese) are not careful about cleanliness, and they do not wash themselves with water when they have done their necessities; but they only wipe themselves with paper". Toilet paper continued to be a valued necessity in China, since it was during the
Hongwu Emperor's reign in AD 1393 that the Bureau of Imperial Supplies (Bao Chao Si) manufactured 720,000 sheets of toilet paper for the entire court (produced of the cheap rice-straw paper). For the emperor's family alone, 15,000 special sheets of paper were made, in light yellow tint and even perfumed. Even at the beginning of the 14th century, during the middle of the
Yuan Dynasty, the amount of toilet paper manufactured for modern-day
Zhejiang province alone amounted to ten million packages holding 1000 to 10000 sheets of toilet paper each. During the
Tang Dynasty (AD
618-907) paper was folded and sewn into square bags to preserve the flavor of tea. During the same period, it was written that tea was served from baskets with multi-colored paper cups and paper napkins of different size and shape. During the Chinese Song Dynasty (AD 960-
1279) not only did the government produce the world's first known paper-printed money, or
banknote (
see Jiaozi (currency) and Huizi), but paper money bestowed as gifts to deserving government officials were wrapped in special paper envelopes.
In America, archaeological evidence indicates that paper was invented by the Mayans no later than the 5th century AD. The Construction of the Codex In Classic- and Postclassic-Period Maya Civilization Maya Codex and Paper Making Called
amatl, it was in widespread use among Mesoamerican cultures until the Spanish conquest. In small quantities, traditional Maya papermaking techniques are still practiced today.
Paper spread slowly outside of China; other
East Asian cultures, even after seeing paper, could not figure out how to make it themselves. Instruction in the manufacturing process was required, and the Chinese were reluctant to share their secrets. The paper was thin and translucent, not like modern western paper, and thus only written on one side. Books were invented in India, of Palm leaves (where we derive the name leaf for a sheet of a book). The technology was first transferred to
Korea in
604 and then imported to
Japan by a Buddhist priests, around
610, where fibres (called
Bast (biology)) from the mulberry tree were used.
Papermaking arrives in the Middle East
After further commercial trading and the defeat of the Chinese in the Battle of Talas in 751, the invention spread to the Middle East.Meggs, Philip B.
A History of Graphic Design. John Wiley & Sons, Inc. 1998. (pp 58) ISBN 0-471-291-98-6 Production was started in Baghdad, where the Arabs invented a method to make a thicker sheet of paper. The manufacture had spread to
Damascus by the time of the First Crusade in the 11th century, but the wars interrupted production, and it split into two centers. Cairo continued with the thicker paper. Iran became the center of the thinner papers. It was also adopted in
India. The first paper mill in Europe was in Spain, at Xavia (modern
Valencia (autonomous community)) in 1120. More mills appeared in
Fabriano Italy in about the
13th century, as an import from
Islamic Spain. They used hemp and
linen rags as a source of fibre. The oldest known paper document in the West is the
Mozarab Missal of Silos from the 11th century, probably written in the Islamic part of Spain. Paper is recorded as being manufactured in both
Italy and Germany by 1400, just about the time when the
woodcut printmaking technique was transferred from fabric to paper in the
old master print and popular prints.
Some historians speculate that paper was a key element in cultural advancement. According to this theory, Chinese culture was less developed than the West in ancient times prior to the Han Dynasty because bamboo, while abundant, was a clumsier writing material than papyrus; Chinese culture advanced during the Han Dynasty and subsequent centuries due to the invention of paper; and Europe advanced during the Renaissance due to the introduction of paper and the
printing press.
Nineteenth Century advances in papermaking
Paper remained expensive, at least in book-sized quantities, through the centuries, until the advent of steam-driven paper making machines in the 19th century, which could make paper with
fibres from
wood pulp. Although older machines predated it, the
Fourdrinier Machine paper making machine became the basis for most modern papermaking. Together with the invention of the practical fountain pen and the mass produced pencil of the same period, and in conjunction with the advent of the steam driven rotary printing press, wood based paper caused a major transformation of the 19th century economy and society in industrialized countries. With the introduction of cheaper paper, schoolbooks, fiction, non-fiction, and newspapers became gradually available by 1900. Cheap wood based paper also meant that keeping personal diaries or writing letters became possible and so, by 1850, the
clerk, or writer, ceased to be a high-status job.
The original wood-based paper was more acidic and more prone to disintegrate over time, through processes known as
slow fires. Documents written on more expensive rag paper were more stable. Mass-market paperback books still use these cheaper mechanical papers (see below), but book publishers can now use acid-free paper for
hardback and
trade paperback books.
Papermaking
Chemical pulping
The purpose of a chemical pulping process is to break down the chemical structure of
lignin and render it soluble in the cooking liquor, so that it may be washed from the
cellulose fibres. Because lignin holds the plant cells together, chemical pulping frees the fibres and makes pulp. The pulp must be
bleaching of wood pulp to produce white paper for
printing, painting and writing. Chemical pulps tend to cost more than mechanical pulps, largely due to the low yield, 40-50% of the original wood. Since the process preserves fibre length, however, chemical pulps tend to make stronger paper. Another advantage of chemical pulping is that the majority of the heat and electricity needed to run the process is produced by burning the lignin removed during pulping.
Papers made from chemical wood-based pulps are also unhelpfully known as
woodfree papers.
The Kraft process produces especially strong, unbleached papers that can be used directly for bags and boxes but are often processed further, e.g. to make corrugated cardboard.
Mechanical pulping
There are two major mechanical pulps, thermomechanical pulp (TMP) and mechanical pulp. The latter is known in the USA as groundwood pulp. In the TMP process, wood is chipped and then fed into large steam-heated refiners where the chips are squeezed and fibreized between two steel discs. In the groundwood process, debarked logs are fed into grinders where they are pressed against rotating stones and fibreized. Mechanical pulping does not remove the lignin, so the yield is very high, >95%, but also causes paper made from this pulp to yellow and become brittle over time. Mechanical pulps have rather short fibre lengths and produce weak paper. Although large amounts of electrical energy are required to produce mechanical pulp, it costs less than chemical pulp.
Recycled paper
Paper recycling processes can use either chemical or mechanical pulp. By mixing with water and applying mechanical action the hydrogen bonds in the paper can be broken and fibres separated again. Most recycled paper contains a proportion of virgin fibre in the interests of quality.
Additives
Besides the fibres, pulps may contain fillers such as chalk or china clay, which improve the characteristics of the paper for printing or writing. Additives for sizing purposes may be mixed into the pulp and/or applied to the paper web later in the manufacturing process. The purpose of sizing is to establish the correct level of surface absorbency to suit the ink or paint.
Drying
After the paper web is produced, the water must be removed from it in order to create a usable product. This is accomplished through pressing and drying. The methods of doing so vary between the different processes used to make paper, but the concepts remain the same.
Pressing the sheet removes the water by force. Once the water is forced from the sheet, another absorbent material must be used to collect this water. On a paper machine this is called a felt (not to be confused with the traditional felt). When making paper by hand, a blotter sheet is used.
Drying involves using air and or heat to remove water from the paper sheet. In the earliest days of papermaking this was done by hanging the paper 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 dryer cans heat to temperatures above 200°F (93°C) and are used in long sequences of more than 40 cans. The heat produced by these can easily dry the paper to less than 6% moisture.
Finishing
The paper may then undergo sizing to alter its physical properties for use in various applications.
Paper at this point is
uncoated.
Coated paper has a thin layer of material such as china clay applied to one or both sides in order to create a surface more suitable for high-resolution halftone screens. (Uncoated papers are rarely suitable for screens above 150 lpi.) Coated or uncoated papers may have their surfaces polished by calendering. Coated papers are divided into matt, semi-matt or silk, and gloss. Gloss papers give the highest
optical density 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.
All paper produced by Fourdrinier-type machines is 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 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."Document Doubles" in Detecting the Truth: Fakes, Forgeries and Trickery, a virtual museum exhibition at Library and Archives Canada
Applications
- To write or print on: the piece of paper becomes a document; this may be for keeping a record (or in the case of printing from a computer or copying from another paper: an additional record) and for communication; see also Reading (activity).
Paper can be produced with a wide variety of properties, depending on its intended use.
- To represent a value:
- For entertainment:
- For packaging:
- For cleaning
- For construction
- Other uses
Types & Weight
Paper is often characterized in terms of weight. In the United States, printing paper is generally 20lb., 24lb., or 32lb. at most. Cover stock is generally 68lb., and 110lb. or more is considered card stock. The weight of 500 sheets of a given paper is the denominating measure of thickness.
The future of paper
Some manufacturers, notably AMD, have started using a new, significantly more environmentally friendly alternative to expanded plastic packaging made out of paper, known commercially as paperfoam. The packaging has very similar mechanical properties to some expanded plastic packaging, but is biodegradable and can also be recycled with ordinary paper.
With increasing environmental concerns about synthetic coatings (such as
PFOA) and the higher prices of hydrocarbon based petrochemicals, there is a focus on zein (corn protein) as a coating for paper in high grease applications such as popcorn bags.
Synthetics such as
Tyvek and Teslin have been introduced as printing media as a more durable material than paper.
In 2006, the world's first "Paper Technology Centre" was opened in Heidenheim, Germany, the headquarters of the Voith paper machine company, at the cost of 75 million Euros .
Notes
References
- Needham, Joseph (1986). Science and Civilization in China: Volume 5, Chemicals and Chemical Technology, Part 1, Paper and Printing. New York: Cambridge University Press, 1985. (also published in Taipei: Caves Books, Ltd., 1986.)
:also referred to as:
- Tsien, Tsuen-Hsuin, '"Paper and Printing," vol. 5 part 1 of Needham, Joseph Science and Civilization in China:. Cambridge University Press, 1986. ISBN 0521086906. (also published in Taipei: Caves Books, Ltd., 1986.)
- "Document Doubles" in Detecting the Truth: Fakes, Forgeries and Trickery, a virtual museum exhibition at Library and Archives Canada
See also
External links
- TAPPI Technical Association of the Pulp and Paper Industry
- How is paper made? at The Straight Dope, 22 November 2005
- How Paper Is Made
- United States Government Printing Office: Government Paper Specification Standards
- How is cotton paper made in India?
- PAPER ROSE VIDEO .
- Heart popup card video .
- FLOWER 01 Video.
- FLOWER 02 Video.
- PAPER ROSES Video.
- CRAZY PAPER CUBE.
Paper is thin material used for writing upon, printing upon or packaging, produced by the amalgamation of
fibres, typically vegetable fibers composed of
cellulose, which are subsequently held together by hydrogen bonding. While the fibres used are usually natural in origin, a wide variety of synthetic fibres, such as polypropylene and polyethylene, may be incorporated into paper as a way of imparting desirable physical properties. The most common source of these kinds of fibres is
wood pulp from
pulpwood trees. fibre crop materials such as
cotton, hemp,
linen, and rice are also used.
Papyrus and parchment
The word
paper derives from the Greek term for the ancient
Egyptian writing material called
papyrus, which was formed from beaten strips of Cyperus papyrus. Papyrus was produced as early as 3000 BC in Egypt, and sold to ancient Greece and
Rome. The establishment of the
Library of Alexandria in the 3rd century BC put a drain on the supply of papyrus. As a result, according to the Roman historian Pliny the Elder (Natural History records, xiii.21), parchment was invented under the patronage of
Eumenes of Pergamum to build his rival library at Pergamum. Outside of Egypt,
parchment or
vellum, made of processed
sheepskin or
calfskin, replaced papyrus as the papyrus plant requires subtropical conditions to grow.
Early papermaking in China
Paper is considered to be one of the
Four Great Inventions of Ancient China, as the first standard papermaking process was developed in China during the early 2nd century. During the
Shang Dynasty (1600 BC-1050 BC) and
Zhou Dynasty (
1050 BC-256 BC) dynasties of ancient China, documents were ordinarily written on bone or
bamboo (on tablets or on bamboo strips sewn and rolled together into scrolls), making them very heavy and awkward to transport. The light material of silk was sometimes used, but was normally too expensive to consider. Indeed, most of the above materials were rare and costly. While the Han Dynasty
China court official
Cai Lun is widely regarded to have first invented the modern method of papermaking (inspired from wasps and bees) from wood pulp in 105 AD, the discovery of specimens bearing written Chinese characters in
2006 at north-west China's Gansu province suggest that paper was in use by the ancient Chinese military more than 100 years before Cai in 8 BC. Archeologically however, true paper without writing has been excavated in China dating to the reign of
Emperor Wu of Han from the 2nd century BC, used for purposes of wrapping or padding protection for delicate bronze mirrors.Needham, Volume 4, 122. It was also used for safety, such as the padding of poisonous 'medicine' as mentioned in the official history of the period. Although paper used for writing became widespread by the 3rd century,Needham, Volume 4, 1. paper continued to be used for wrapping (and other) purposes.
), the
Diamond Sutra of AD 868, shows the widespread availability and practicality of paper in China.
Toilet paper was used in China by at least the 6th century AD.Needham, Volume 4, 123. In AD 589, the Chinese scholar-official Yan Zhitui (531-
591 AD) once wrote: "Paper on which there are quotations or commentaries from
Five Classics or the names of sages, I dare not use for toilet purposes". An Arab traveler to China once wrote of the curious Chinese tradition of toilet paper in AD 851, writing: "They (the Chinese) are not careful about cleanliness, and they do not wash themselves with water when they have done their necessities; but they only wipe themselves with paper". Toilet paper continued to be a valued necessity in China, since it was during the
Hongwu Emperor's reign in AD 1393 that the Bureau of Imperial Supplies (Bao Chao Si) manufactured 720,000 sheets of toilet paper for the entire court (produced of the cheap rice-straw paper). For the emperor's family alone, 15,000 special sheets of paper were made, in light yellow tint and even perfumed. Even at the beginning of the 14th century, during the middle of the Yuan Dynasty, the amount of toilet paper manufactured for modern-day Zhejiang province alone amounted to ten million packages holding 1000 to 10000 sheets of toilet paper each. During the
Tang Dynasty (AD
618-907) paper was folded and sewn into square bags to preserve the flavor of tea. During the same period, it was written that tea was served from baskets with multi-colored paper cups and paper napkins of different size and shape. During the Chinese Song Dynasty (AD 960-1279) not only did the government produce the world's first known paper-printed money, or
banknote (
see Jiaozi (currency) and Huizi), but paper money bestowed as gifts to deserving government officials were wrapped in special paper
envelopes.
In America, archaeological evidence indicates that paper was invented by the Mayans no later than the 5th century AD. The Construction of the Codex In Classic- and Postclassic-Period Maya Civilization Maya Codex and Paper Making Called
amatl, it was in widespread use among Mesoamerican cultures until the Spanish conquest. In small quantities, traditional Maya papermaking techniques are still practiced today.
Paper spread slowly outside of China; other East Asian cultures, even after seeing paper, could not figure out how to make it themselves. Instruction in the manufacturing process was required, and the Chinese were reluctant to share their secrets. The paper was thin and translucent, not like modern western paper, and thus only written on one side. Books were invented in India, of Palm leaves (where we derive the name leaf for a sheet of a book). The technology was first transferred to Korea in
604 and then imported to Japan by a Buddhist priests, around 610, where fibres (called
Bast (biology)) from the mulberry tree were used.
Papermaking arrives in the Middle East
After further commercial trading and the defeat of the Chinese in the Battle of Talas in 751, the invention spread to the
Middle East.Meggs, Philip B.
A History of Graphic Design. John Wiley & Sons, Inc. 1998. (pp 58) ISBN 0-471-291-98-6 Production was started in Baghdad, where the Arabs invented a method to make a thicker sheet of paper. The manufacture had spread to
Damascus by the time of the
First Crusade in the 11th century, but the wars interrupted production, and it split into two centers.
Cairo continued with the thicker paper. Iran became the center of the thinner papers. It was also adopted in India. The first paper mill in Europe was in
Spain, at Xavia (modern
Valencia (autonomous community)) in 1120. More mills appeared in Fabriano
Italy in about the
13th century, as an import from
Islamic Spain. They used
hemp and linen rags as a source of fibre. The oldest known paper document in the West is the Mozarab
Missal of Silos from the 11th century, probably written in the Islamic part of Spain. Paper is recorded as being manufactured in both Italy and Germany by 1400, just about the time when the woodcut printmaking technique was transferred from fabric to paper in the old master print and
popular prints.
Some historians speculate that paper was a key element in cultural advancement. According to this theory, Chinese culture was less developed than the West in ancient times prior to the Han Dynasty because bamboo, while abundant, was a clumsier writing material than papyrus; Chinese culture advanced during the Han Dynasty and subsequent centuries due to the invention of paper; and Europe advanced during the Renaissance due to the introduction of paper and the printing press.
Nineteenth Century advances in papermaking
Paper remained expensive, at least in book-sized quantities, through the centuries, until the advent of steam-driven paper making machines in the 19th century, which could make paper with fibres from
wood pulp. Although older machines predated it, the
Fourdrinier Machine paper making machine became the basis for most modern papermaking. Together with the invention of the practical
fountain pen and the mass produced
pencil of the same period, and in conjunction with the advent of the steam driven rotary
printing press, wood based paper caused a major transformation of the 19th century economy and society in industrialized countries. With the introduction of cheaper paper, schoolbooks, fiction, non-fiction, and newspapers became gradually available by 1900. Cheap wood based paper also meant that keeping personal diaries or writing letters became possible and so, by 1850, the clerk, or writer, ceased to be a high-status job.
The original wood-based paper was more acidic and more prone to disintegrate over time, through processes known as
slow fires. Documents written on more expensive rag paper were more stable. Mass-market paperback books still use these cheaper mechanical papers (see below), but book publishers can now use acid-free paper for hardback and
trade paperback books.
Papermaking
Chemical pulping
The purpose of a chemical pulping process is to break down the chemical structure of lignin and render it soluble in the cooking liquor, so that it may be washed from the
cellulose fibres. Because lignin holds the plant cells together, chemical pulping frees the fibres and makes pulp. The pulp must be
bleaching of wood pulp to produce white paper for printing, painting and writing. Chemical pulps tend to cost more than mechanical pulps, largely due to the low yield, 40-50% of the original wood. Since the process preserves fibre length, however, chemical pulps tend to make stronger paper. Another advantage of chemical pulping is that the majority of the heat and electricity needed to run the process is produced by burning the lignin removed during pulping.
Papers made from chemical wood-based pulps are also unhelpfully known as
woodfree papers.
The
Kraft process produces especially strong, unbleached papers that can be used directly for bags and boxes but are often processed further, e.g. to make corrugated cardboard.
Mechanical pulping
There are two major mechanical pulps, thermomechanical pulp (TMP) and mechanical pulp. The latter is known in the USA as groundwood pulp. In the TMP process, wood is chipped and then fed into large steam-heated refiners where the chips are squeezed and fibreized between two steel discs. In the groundwood process, debarked logs are fed into grinders where they are pressed against rotating stones and fibreized. Mechanical pulping does not remove the lignin, so the yield is very high, >95%, but also causes paper made from this pulp to yellow and become brittle over time. Mechanical pulps have rather short fibre lengths and produce weak paper. Although large amounts of electrical energy are required to produce mechanical pulp, it costs less than chemical pulp.
Recycled paper
Paper recycling processes can use either chemical or mechanical pulp. By mixing with water and applying mechanical action the hydrogen bonds in the paper can be broken and fibres separated again. Most recycled paper contains a proportion of virgin fibre in the interests of quality.
Additives
Besides the fibres, pulps may contain fillers such as chalk or china clay, which improve the characteristics of the paper for printing or writing. Additives for sizing purposes may be mixed into the pulp and/or applied to the paper web later in the manufacturing process. The purpose of sizing is to establish the correct level of surface absorbency to suit the ink or paint.
Drying
After the paper web is produced, the water must be removed from it in order to create a usable product. This is accomplished through pressing and drying. The methods of doing so vary between the different processes used to make paper, but the concepts remain the same.
Pressing the sheet removes the water by force. Once the water is forced from the sheet, another absorbent material must be used to collect this water. On a paper machine this is called a felt (not to be confused with the traditional
felt). When making paper by hand, a blotter sheet is used.
Drying involves using air and or heat to remove water from the paper sheet. In the earliest days of papermaking this was done by hanging the paper 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 dryer cans heat to temperatures above 200°F (93°C) and are used in long sequences of more than 40 cans. The heat produced by these can easily dry the paper to less than 6% moisture.
Finishing
The paper may then undergo sizing to alter its physical properties for use in various applications.
Paper at this point is
uncoated.
Coated paper has a thin layer of material such as china clay applied to one or both sides in order to create a surface more suitable for high-resolution
halftone screens. (Uncoated papers are rarely suitable for screens above 150 lpi.) Coated or uncoated papers may have their surfaces polished by calendering. Coated papers are divided into matt, semi-matt or silk, and gloss. Gloss papers give the highest
optical density 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.
All paper produced by Fourdrinier-type machines is 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 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."Document Doubles" in Detecting the Truth: Fakes, Forgeries and Trickery, a virtual museum exhibition at Library and Archives Canada
Applications
- To write or print on: the piece of paper becomes a document; this may be for keeping a record (or in the case of printing from a computer or copying from another paper: an additional record) and for communication; see also Reading (activity).
Paper can be produced with a wide variety of properties, depending on its intended use.
- To represent a value:
- For entertainment:
- For packaging:
- For cleaning
- For construction
- Other uses
Types & Weight
Paper is often characterized in terms of weight. In the United States, printing paper is generally 20lb., 24lb., or 32lb. at most. Cover stock is generally 68lb., and 110lb. or more is considered card stock. The weight of 500 sheets of a given paper is the denominating measure of thickness.
The future of paper
Some manufacturers, notably AMD, have started using a new, significantly more environmentally friendly alternative to expanded plastic packaging made out of paper, known commercially as paperfoam. The packaging has very similar mechanical properties to some expanded plastic packaging, but is biodegradable and can also be recycled with ordinary paper.
With increasing environmental concerns about synthetic coatings (such as
PFOA) and the higher prices of hydrocarbon based petrochemicals, there is a focus on
zein (corn protein) as a coating for paper in high grease applications such as popcorn bags.
Synthetics such as
Tyvek and Teslin have been introduced as printing media as a more durable material than paper.
In 2006, the world's first "Paper Technology Centre" was opened in Heidenheim, Germany, the headquarters of the
Voith paper machine company, at the cost of 75 million Euros .
Notes
References
- Needham, Joseph (1986). Science and Civilization in China: Volume 5, Chemicals and Chemical Technology, Part 1, Paper and Printing. New York: Cambridge University Press, 1985. (also published in Taipei: Caves Books, Ltd., 1986.)
:also referred to as:
- Tsien, Tsuen-Hsuin, '"Paper and Printing," vol. 5 part 1 of Needham, Joseph Science and Civilization in China:. Cambridge University Press, 1986. ISBN 0521086906. (also published in Taipei: Caves Books, Ltd., 1986.)
- "Document Doubles" in Detecting the Truth: Fakes, Forgeries and Trickery, a virtual museum exhibition at Library and Archives Canada
See also
- Paper recycling
- Arches paper
- Paper size
- Buckypaper
- Graphene Oxide Paper
External links
- TAPPI Technical Association of the Pulp and Paper Industry
- How is paper made? at The Straight Dope, 22 November 2005
- How Paper Is Made
- United States Government Printing Office: Government Paper Specification Standards
- How is cotton paper made in India?
- PAPER ROSE VIDEO .
- Heart popup card video .
- FLOWER 01 Video.
- FLOWER 02 Video.
- PAPER ROSES Video.
- CRAZY PAPER CUBE.
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