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Paper Composition Ⅱ

Sizing.   Sizing materials include starch and rosin. These ingredients may be added internally, externally, or both. Internal sizing is intended to give the paper water resistance, a key factor in papers used for lithography. Rosin and papermaker’s alum are two materials commonly used for internal sizing. Surface sizing controls the absorption of printing ink, allowing for crisper images on the paper surface. surface sizing also reduces the release of surface fibers onto blankets, a problem called picking. In addition, sizing may also serve as a preliminary treatment for subsequent coating of the paper.

Paper Composition Ⅰ

Cellulose fiber. The principal raw material for producing paper is cellulose fibers, which are short, threadlike structures. Cellulose fiber is the basic building block of plant matter, and large amounts of it can be extracted from wood. There are four main sources of cellulose fiber used in the manufacture of paper: softwood trees, hardwood trees, recycled fiber, and rag. As a fifth option, synthetic fibers are sometimes used for specialty papers. Other plants, such as sugar cane or bamboo, are also used as fiber sources
Softwood and hardwood trees are the most commonly used sources of fiber for sheetfed offset papers. Each source produces fiber with slightly different characteristics. Hardwood trees like poplar, birch, and maples produces shorter fibers, about 1mm in length. softwood trees like spruce, pine, and fir produce longer fibers, about 3mm in length. The longer softwood fibers tend to give paper more strength due to better interlocking of the fibers. The shorter hardwood fibers provide paper with and better surface smoothness.
Trees are replenishable, easily harvested, and easily transportable, making them the ideal sourcce of cellulose in papermaking. Cellulose fibers have a very high tensile strength and a great affinity for water, meaning that the fibers can be bonded together strongly in a network to form paper. The size and shape of fibers, which vary with type of tree and even within a given tree, have an important influence on paper progerties.
Paper is made up of a variety of ingredients in addition to fiber, including sizing materials, mineral fillers, and coloring matter.

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Making paper by hand

Making paper by hand

Making paper by hand is an excellent way to become familifr with the basic paper dures of papermaking. Extensive equipment and materials are not required
Equipment includes a tub or large pail, a mold and a deckle. These three items are shown in Figure. The mold is a wooden frame covered with a metal scree.. The deckle Is another frame the same size as the mold. Other items needed are an gee beater, a rolling pin, an electric iron, blotting paper, instant laundry starch, and a box of soft facial tissues.
Papermaking is a rather simple process. Fill the tub with warm water. If wood pulp is available, it can be used. if not, shred about thirty tissues into the water. Do not use the “wet strength” kind. The tissues substitute for the wood pulp.
Now add one tablespoon of instant laundry starch to two cups of water. Pour this mixture into the tub. The starch serves to size or fill the pores of the paper that will be made.
Now beat the pulp minture with an egg beater until it is free from lumps.
You are now ready to form the sheet of paper. Place the deckle over the mold and slide both into the pulp mixture. After levling the deckle and mold assembly. lift it carefully from the mixture.
Remove the deckle from the mold and transfer the newly made sheet of paper to a piece of blotting paper. Now cover the newly made paper with a second blotter and press out the excess water with a rolling pin. Complete the drying process by pressing the paper with an electric iron. Do this while the sheet is still between the blotting papers. You have just made a sheet of paper by hand.

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Paper

paper

Paper Many types of materials can be printed…Plastic,glass and fabric are just some. However,by far the most important printed material is paper. Paper is needed for letterheads, envelopes, invoices, checks, travel brochures, calendars, advertising pieces and catalogs. And , of course , paper is an essential ingredient in newspapers, books, and magazines.
Ts’ai lun a chinese court official, is credited with the invention of paper. He did this nearly 1900 years ago in the year 105 A.D.
Prior to the invention of paper, writing was done on a variety of materials . For example animal skins called parchment and vellum were used by ancient Greeks. Papyrus, a writing surface made by pounding a woven mat of papyrus reed into a thin, hard sheet, was used by ancient Egyptians. In fact, the word paper is derived from the word papyrus.
Paper making techniques were introduces to the Western world in the tench century A.D. These techniques were brought to Spain by dipping a screen into a vat containing water and rag fibers . Openings in the screen were large enough to allow the water to drain but small enough to keep the fibers from passing through. The screen was withdrawn, and the matted fibers that remained dried and formed paper. Making paper by hard was a slow and tedious process.
With the invention of movable type in the fifteenth century, the need for paper increased dramatically. However, the urgent demand for inexpensive paper could not be met until the middle of the nineteenth century, when papermaking machines were put into general use. Today, the average amount of paper used each year by every person in the world is still increasing.

Relief or letterpress printing

When ink is applied to a raised surface and paper is pressed against the inked surface, the ink is transferred to the paper. Relief and letterpress are terms that describe printing methods that use this principle. The rubber stamp is a device that prints by the relief or letterpress method. It transfers ink a raised surface to paper. Type write elements, also print in this way.

Pantone

    Pantone is a standardized color matching system, utilizing the Pantone numbering system for identifying colors. By standardizing the colors, different manufacturers in different locations can all reference a Pantone numbered color, making sure colors match without direct contact with one another. The most commonly referenced colors are in the Pantone solids palette. The Pantone Solid palette consists of 1,114 colors, identified by three or four digit numbers, followed by a C, U, Or M suffix.. Originally designed for the graphics industry, the pantone solids palette is now used by a wide range of industries, and is the most commonly used palette. For example, Pantone 395 Yellow can be identified as Pantone 395C (C= Coated Paper), Pantone 395U (U= Uncoated Paper) or Pantone 395M (M=Matte Paper).

Aluminum Foil Paper

Aluminum Foil Paper

The combination of thin Aluminum foil with a paper backing used as a positive moisture barrier. Normal combination is kraft backing with Aluminum foil laminated to the kraft by means of asphalt, adhesive, or polyethylene. The Aluminum foil can also be coated with polyethylene.

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Art paper

Art paper

Art paper

High quality and rather heavy two-side coated printing paper with smooth surface. The reproduction of fine screen single- and multicolor pictures (‘art on paper’) requires a paper that has an even, well closed surface and a uniform ink absorption.

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LWC paper

Light Weight Coated (LWC) Paper

Coating applied at 7-10 g m2 on one or both sides of the paper.

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PE coated paper

PE coated paper

The paper which is coated with polyethylene by extrusion coating process.  It will have a shiny appearance on the coated side but will not have gloss levels comparable to glossy or machine glazed paper. Normally use for wrapping hamburger,sandwich,chicken rolls etc.