Sizing
Overview
 
Sizing or size is any one of numerous specific substances that is applied to or incorporated in other material, especially papers and textiles, to act as a protecting filler
Filler (materials)
Fillers are particles added to material to lower the consumption of more expensive binder material or to better some properties of the mixtured material...

 or glaze
Coating
Coating is a covering that is applied to the surface of an object, usually referred to as the substrate. In many cases coatings are applied to improve surface properties of the substrate, such as appearance, adhesion, wetability, corrosion resistance, wear resistance, and scratch resistance...

.
Sizing is used in papermaking
Papermaking
Papermaking is the process of making paper, a substance which is used universally today for writing and packaging.In papermaking a dilute suspension of fibres in water is drained through a screen, so that a mat of randomly interwoven fibres is laid down. Water is removed from this mat of fibres by...

 and textile manufacturing
Textile manufacturing
Textile manufacturing is a major industry. It is based in the conversion of three types of fibre into yarn, then fabric, then textiles. These are then fabricated into clothes or other artifacts. Cotton remains the most important natural fibre, so is treated in depth...

 to change the absorption and wear characteristics of those materials; it is used as a surface preparation for gilding
Gilding
The term gilding covers a number of decorative techniques for applying fine gold leaf or powder to solid surfaces such as wood, stone, or metal to give a thin coating of gold. A gilded object is described as "gilt"...

; and it is used by painters and artists to prepare paper and textile surfaces for some art techniques.

Sizing also refers to the process of including or applying the substance.
Sizing is used during paper
Paper
Paper is a thin material mainly used for writing upon, printing upon, drawing or for packaging. It is produced by pressing together moist fibers, typically cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets....

 manufacture in order to reduce the paper's tendency when dry to absorb liquid, with the goal of allowing inks and paints to remain on the surface of the paper and to dry there, rather than be absorbed into the paper.
Encyclopedia
Sizing or size is any one of numerous specific substances that is applied to or incorporated in other material, especially papers and textiles, to act as a protecting filler
Filler (materials)
Fillers are particles added to material to lower the consumption of more expensive binder material or to better some properties of the mixtured material...

 or glaze
Coating
Coating is a covering that is applied to the surface of an object, usually referred to as the substrate. In many cases coatings are applied to improve surface properties of the substrate, such as appearance, adhesion, wetability, corrosion resistance, wear resistance, and scratch resistance...

.
Sizing is used in papermaking
Papermaking
Papermaking is the process of making paper, a substance which is used universally today for writing and packaging.In papermaking a dilute suspension of fibres in water is drained through a screen, so that a mat of randomly interwoven fibres is laid down. Water is removed from this mat of fibres by...

 and textile manufacturing
Textile manufacturing
Textile manufacturing is a major industry. It is based in the conversion of three types of fibre into yarn, then fabric, then textiles. These are then fabricated into clothes or other artifacts. Cotton remains the most important natural fibre, so is treated in depth...

 to change the absorption and wear characteristics of those materials; it is used as a surface preparation for gilding
Gilding
The term gilding covers a number of decorative techniques for applying fine gold leaf or powder to solid surfaces such as wood, stone, or metal to give a thin coating of gold. A gilded object is described as "gilt"...

; and it is used by painters and artists to prepare paper and textile surfaces for some art techniques.

Sizing also refers to the process of including or applying the substance.

Papermaking

Sizing is used during paper
Paper
Paper is a thin material mainly used for writing upon, printing upon, drawing or for packaging. It is produced by pressing together moist fibers, typically cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets....

 manufacture in order to reduce the paper's tendency when dry to absorb liquid, with the goal of allowing inks and paints to remain on the surface of the paper and to dry there, rather than be absorbed into the paper. This provides a more consistent, economical, and precise printing, painting, and writing surface. This is achieved by curbing the paper fibers' tendency to absorb liquids by capillary action
Capillary action
Capillary action, or capilarity, is the ability of a liquid to flow against gravity where liquid spontanously rise in a narrow space such as between the hair of a paint-brush, in a thin tube, or in porous material such as paper or in some non-porous material such as liquified carbon fiber, or in a...

. In addition, sizing affects abrasiveness, creasibility, finish, printability
Paper and ink testing
A variety of tests are used to determine ink and paper quality, and to measure their interactions. They are necessary to balance print quality, cost, and wear on the press.-List of paper and ink tests:Some of the paper and ink tests are listed here:...

, smoothness, and surface bond strength and decreases surface porosity
Porosity
Porosity or void fraction is a measure of the void spaces in a material, and is a fraction of the volume of voids over the total volume, between 0–1, or as a percentage between 0–100%...

 and fuzzing.

There are three categories of papers with respect to sizing: unsized (water-leaf), weak sized (slack sized), and strong sized (hard sized). Waterleaf has low water resistance and includes absorbent papers for blotting
Blotting paper
Blotting paper is a highly absorbent type of paper or other material. It is used to absorb an excess of liquid substances from the surface of writing paper or objects. It is also commonly used as a beauty tool to absorb excess oil from the skin.-Manufacture:Blotting paper is made from different...

. Slack sized paper is somewhat absorbent and includes newsprint
Newsprint
Newsprint is a low-cost, non-archival paper most commonly used to print newspapers, and other publications and advertising material. It usually has an off-white cast and distinctive feel. It is designed for use in printing presses that employ a long web of paper rather than individual sheets of...

, while hard sized papers have the highest water resistance, such as coated fine papers and liquid packaging board.

There are two types of sizing: internal sizing, sometimes also called engine sizing, and surface sizing (tub sizing). Internal sizing is applied to almost all papers and especially to all those that are machine made, while surface sizing is added for the highest grade bond
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 name comes from it having originally been made for documents such as government bonds. It is now used for letterheads, other stationery and as paper for electronic printers...

, ledger
Ledger
A ledger is the principal book or computer file for recording and totaling monetary transactions by account, with debits and credits in separate columns and a beginning balance and ending balance for each account. The ledger is a permanent summary of all amounts entered in supporting journals which...

, and writing paper
Writing paper
Printing and writing papers are paper grades used for newspapers, magazines, catalogs, books, commercial printing, business forms, stationeries, copying and digital printing. About 1/3 of the total pulp and paper marked is printing and writing papers....

s.

Surface sizing

Surface sizing solutions consists of mainly modified starch
Starch
Starch or amylum is a carbohydrate consisting of a large number of glucose units joined together by glycosidic bonds. This polysaccharide is produced by all green plants as an energy store...

es and sometimes other hydrocolloids, such as gelatine, or surface sizing agents such as alkyl ketene dimer
Diketene
Diketene is an organic compound formed by dimerization of ketene. Diketene is a member of the oxetane family. It is used as a chemical reagent in organic chemistry. It is a colorless liquid and heating regenerates the ketene monomer...

 (AKD) or acrylic co-polymers. Surface sizing agents are amphipathic molecules, having both hydrophilic (water-loving) and hydrophobic (water-repelling) ends. The sizing agent covers the cellulose and forms a film, with the hydrophilic tail facing the fiber and the hydrophobic tail facing outwards. This creates a water-repellent situation. Sizing improves the surface strength, printability, and water resistance of the paper surface. In the sizing solution, optical brightening agents (OBA)
Optical brightener
Optical brighteners, optical brightening agents , fluorescent brightening agents or fluorescent whitening agents are dyes that absorb light in the ultraviolet and violet region of the electromagnetic spectrum, and re-emit light in the blue region...

 may also be added to improve the opacity and whiteness of the paper surface.

Internal sizing

Internal sizing chemicals used in papermaking
Papermaking
Papermaking is the process of making paper, a substance which is used universally today for writing and packaging.In papermaking a dilute suspension of fibres in water is drained through a screen, so that a mat of randomly interwoven fibres is laid down. Water is removed from this mat of fibres by...

 at the wet end are ASA, AKD and rosin
Rosin
.Rosin, also called colophony or Greek pitch , is a solid form of resin obtained from pines and some other plants, mostly conifers, produced by heating fresh liquid resin to vaporize the volatile liquid terpene components. It is semi-transparent and varies in color from yellow to black...

. By making the paper web more hydrophobic, the sizing agents influence dewatering and retention of fillers and fibers in the paper sheet. Next to paper quality, internal sizing agents' main effect is on runability of the paper machine.

Preservation

As the process of sizing had and has the intent of making the paper suitable for printing, it would seem slightly ironic that some processes of sizing would make printing paper a problem for the continued existence of that paper and those who would preserve them. Sizing processes started early on in the paper making processes, with historians citing that items, such as starch, were early sizing agents used on paper. Dard Hunter in Papermaking through Eighteen Centuries corroborates this by writing, “The Chinese used starch as a size for paper as early as A.D. 768 and its use continued until the fourteenth century when animal glue was substituted.” In the early modern paper mills in Europe, which produced paper for printing and other uses, the sizing agent of choice was gelatin
Gelatin
Gelatin is a translucent, colorless, brittle , flavorless solid substance, derived from the collagen inside animals' skin and bones. It is commonly used as a gelling agent in food, pharmaceuticals, photography, and cosmetic manufacturing. Substances containing gelatin or functioning in a similar...

, as Susan Swartzburg writes in Preserving Library Materials: “Various substances have been used for sizing through the ages, from gypsum to animal gelatin.” Hunter describes the process of sizing in these paper mills in the following:
With the advent of the mass production of paper, the type of size used for paper production also changed. As Swartzburg writes, “By 1850 rosin
Rosin
.Rosin, also called colophony or Greek pitch , is a solid form of resin obtained from pines and some other plants, mostly conifers, produced by heating fresh liquid resin to vaporize the volatile liquid terpene components. It is semi-transparent and varies in color from yellow to black...

 size had come into use. Unfortunately, it produces a chemical action that hastens the decomposition of even the finest papers.” In the field of library preservation it is known “that acid hydrolysis of cellulose and related carbo-hydrates [sic] is one of the key factors responsible for the degradation of paper during ageing.” Some recent professional work has focused on the specific in the degradation involved in the deterioration of paper that has had a rosin sizing process, and what amount of rosin affects the deterioration process, in addition to work on developing permanent paper and sizing agents that will not eventually destroy the paper. An issue on the periphery to the preservation of paper and sizing, is washing, which is described by V. Daniels and J. Kosek as, “The removal of discolouration ... in water is principally effected by the dissolution of water-soluble material; this is usually done by immersing paper in water.” In such a process, surface level items applied to the paper, such as size in early paper making processes as seen above, have the possibility of being removed from the paper, which might have some item specific interest in a special collections library. With later processes in paper making being more akin to “engine sizing,” as H. Hardman and E. J. Cole describe it, “Engine sizing, with is part of the manufacturing process, has the ingredients added to the furnish or stock prior to sheet formation,” the concern for the removal of size is less, and as such, most literature focuses on the more pressing issue of preserving acidic papers and similar issues.

Gilding

Sizing is applied to surfaces before gilding
Gilding
The term gilding covers a number of decorative techniques for applying fine gold leaf or powder to solid surfaces such as wood, stone, or metal to give a thin coating of gold. A gilded object is described as "gilt"...

 in order to remove small surface imperfections that would otherwise be highlighted by the very thin metal used.

Textile warp sizing

Sizing of the warp yarn
Warp (weaving)
In weaving cloth, the warp is the set of lengthwise yarns that are held in tension on a frame or loom. The yarn that is inserted over-and-under the warp threads is called the weft, woof, or filler. Each individual warp thread in a fabric is called a warp end or end. Warp means "that which is thrown...

 is essential to reduce breakage of the yarn
Yarn
Yarn is a long continuous length of interlocked fibres, suitable for use in the production of textiles, sewing, crocheting, knitting, weaving, embroidery and ropemaking. Thread is a type of yarn intended for sewing by hand or machine. Modern manufactured sewing threads may be finished with wax or...

 and thus production stops on the weaving
Weaving
Weaving is a method of fabric production in which two distinct sets of yarns or threads are interlaced at right angles to form a fabric or cloth. The other methods are knitting, lace making and felting. The longitudinal threads are called the warp and the lateral threads are the weft or filling...

 machine. On the weaving machine, the warp yarns are subjected to several types of actions i.e. cyclic strain, flexing, abrasion at various loom
Loom
A loom is a device used to weave cloth. The basic purpose of any loom is to hold the warp threads under tension to facilitate the interweaving of the weft threads...

 parts and inter yarn friction.

With sizing the strength - abrasion resistance - of the yarn will improve and the hairiness of yarn will decrease. The degree of improvement of strength depends on adhesion force between fiber and size, size penetration as well as encapsulation of yarn.
Different types of water soluble polymers called textile sizing agents/chemicals such as modified starch
Starch
Starch or amylum is a carbohydrate consisting of a large number of glucose units joined together by glycosidic bonds. This polysaccharide is produced by all green plants as an energy store...

, polyvinyl alcohol
Polyvinyl alcohol
Polyvinyl alcohol is a water-soluble synthetic polymer .-Properties:...

 (PVA), carboxymethyl cellulose
Carboxymethyl cellulose
Carboxymethyl cellulose or cellulose gum is a cellulose derivative with carboxymethyl groups bound to some of the hydroxyl groups of the glucopyranose monomers that make up the cellulose backbone...

 (CMC), acrylates are used to protect the yarn. Also wax
Wax
thumb|right|[[Cetyl palmitate]], a typical wax ester.Wax refers to a class of chemical compounds that are plastic near ambient temperatures. Characteristically, they melt above 45 °C to give a low viscosity liquid. Waxes are insoluble in water but soluble in organic, nonpolar solvents...

 is added to reduce the abrasiveness of the warp yarns.
The type of yarn material (e.g. cotton
Cotton
Cotton is a soft, fluffy staple fiber that grows in a boll, or protective capsule, around the seeds of cotton plants of the genus Gossypium. The fiber is almost pure cellulose. The botanical purpose of cotton fiber is to aid in seed dispersal....

, polyester
Polyester
Polyester is a category of polymers which contain the ester functional group in their main chain. Although there are many polyesters, the term "polyester" as a specific material most commonly refers to polyethylene terephthalate...

, linen
Linen
Linen is a textile made from the fibers of the flax plant, Linum usitatissimum. Linen is labor-intensive to manufacture, but when it is made into garments, it is valued for its exceptional coolness and freshness in hot weather....

), the thickness of the yarn, type of weaving machinery will determine the sizing recipe.

The sizing liquor is applied on warp yarn with a warp sizing machine.
After the weaving process the fabric is desized
Desizing
Desizing is the process of removing the size material from the warp yarns in woven fabrics.-Sizing agents:Sizing agents are selected on the basis of type of fabric, environmental friendliness, ease of removal, cost considerations, effluent treatment, etc.-Natural sizing agents:Natural sizing agents...

 (washed).

See also

  • Preservation (library and archival science)
    Preservation (library and archival science)
    Preservation is a branch of library and information science concerned with maintaining or restoring access to artifacts, documents and records through the study, diagnosis, treatment and prevention of decay and damage....

  • Acid-free paper
    Acid-free paper
    Acid-free paper is paper that has a neutral or basic pH . It can be made from any cellulose fiber as long as the active acid pulp is eliminated during processing. It is also lignin and sulfur free...

  • Textile manufacturing
    Textile manufacturing
    Textile manufacturing is a major industry. It is based in the conversion of three types of fibre into yarn, then fabric, then textiles. These are then fabricated into clothes or other artifacts. Cotton remains the most important natural fibre, so is treated in depth...

  • Paper chemicals
    Paper chemicals
    -Optical brightening agent:Optical brightener is used to make paper appear more white. Optical brightening agents use fluorescence to absorb invisible radiation from the ultraviolet part of the light spectrum and re-emit the radiation as light in the visible blue range. The optical brightening...


External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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