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 A polymer (; Greek '' poly-'', "many" + '' -mer'', "part") is a substance or material consisting of very large molecules called macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic a ...

to impart certain qualities to the paper, including weight, surface gloss, smoothness, or reduced ink absorbency. Various materials, including

kaolinite Kaolinite ( ) is a clay mineral, with the chemical composition Al2 Si2 O5( OH)4. It is an important industrial mineral. It is a layered silicate mineral, with one tetrahedral sheet of silica () linked through oxygen atoms to one octahed ...

, calcium carbonate, bentonite, and talc, can be used to coat paper for high-quality printing used in the

packaging industry {{set category, first= industries (branches of an economy), alternative=industries, topic=Industry (economics) For other meanings of "industries", see :Industries. ...

and in magazines. The

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 is bound to the paper with synthetic s, such as styrene-butadiene

latex Latex is an emulsion (stable dispersion) of polymer microparticles in water. Latexes are found in nature, but synthetic latexes are common as well. In nature, latex is found as a milky fluid found in 10% of all flowering plants (angiosperms ...

es and natural organic binders such as

starch Starch or amylum is a polymeric carbohydrate consisting of numerous glucose units joined by glycosidic bonds. This polysaccharide is produced by most green plants for energy storage. Worldwide, it is the most common carbohydrate in human die ...

. The coating formulation may also contain chemical additives as

dispersant A dispersant or a dispersing agent is a substance, typically a surfactant, that is added to a suspension of solid or liquid particles in a liquid (such as a colloid or emulsion) to improve the separation of the particles and to prevent their sett ...

resin In polymer chemistry and materials science, resin is a solid or highly viscous substance of plant or synthetic origin that is typically convertible into polymers. Resins are usually mixtures of organic compounds. This article focuses on nat ...

s, or

polyethylene Polyethylene or polythene (abbreviated PE; IUPAC name polyethene or poly(methylene)) is the most commonly produced plastic. It is a polymer, primarily used for packaging ( plastic bags, plastic films, geomembranes and containers including b ...

to give water resistance and

wet strength The wet strength of paper and paperboard is a measure of how well the web of fibers holding the paper together can resist a force of rupture when the paper is wet. Wet strength is routinely expressed as the ratio of wet to dry tensile force at bre ...

to the paper, or to protect against ultraviolet radiation.

Varieties

Machine-finished coated paper

''Machine-finished coated paper'' (MFC) has a basis weight of 48–80 g/m². They have good surface properties, high print gloss and adequate sheet stiffness. MFC papers are made of 60–85% groundwood or

TMP TMP can refer to any of the following: Chemistry * 2,2,6,6-Tetramethylpiperidine, an organic chemistry reagent * Thymidine monophosphate, a nucleotide * Trimethoprim, an antibiotic * Trimethyl phosphate, a solvent * Trimethylolpropane, a precurso ...

and 15–40% chemical pulp with a total

pigment A pigment is a colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic compou ...

content of 20–30%. The paper can be soft nip calendered or supercalendered. These are often used in

paperbacks A paperback (softcover, softback) book is one with a thick paper or paperboard cover, and often held together with glue rather than stitches or staples. In contrast, hardcover (hardback) books are bound with cardboard covered with cloth, l ...

Coated fine paper

''Coated fine paper'' or ''woodfree coated paper'' (WFC) are primarily produced for

offset printing Offset printing is a common printing technique in which the inked image is transferred (or "offset") from a plate to a rubber blanket and then to the printing surface. When used in combination with the lithographic process, which is based on ...

: ; Standard coated fine papers: This paper quality is normally used for advertising materials, books, annual reports and high-quality catalogs.

Grammage Grammage and basis weight, in the pulp and paper industry, are the area density of a paper product, that is, its mass per unit of area. Two ways of expressing grammage are commonly used: * Expressed in grams (g) per square meter (g/m2), regar ...

ranges from 90–170 g/m² and ISO brightness between 80–96%. The fibre furnish consists of more than 90% chemical pulp. Total

content are in the range 30–45%, where calcium carbonate and clay are the most common. ; Low coat weight papers: These paper grades have lower coat weights than the standard WFC (3–14 g/m²/side) and the grammage and pigment content are also generally lower, 55–135 g/m² and 20–35% respectively. ; s: Art papers are one of the highest-quality printing papers and are used for illustrated books, calendars and brochures. The grammage varies from 100 to 230 g/m². These papergrades are triple coated with 20–40 g/m²/side and have matte or glossy finish. Higher qualities often contain

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 ...

Plastic coatings

Plastic-coated paper includes types of paper coatings;

polyolefin A polyolefin is a type of polymer with the general formula (CH2CHR)n where R is an alkyl group. They are usually derived from a small set of simple olefins (alkenes). Dominant in a commercial sense are polyethylene and polypropylene. More speciali ...

extrusion coating,

silicone A silicone or polysiloxane is a polymer made up of siloxane (−R2Si−O−SiR2−, where R = organic group). They are typically colorless oils or rubber-like substances. Silicones are used in sealants, adhesives, lubricants, medicine, cookin ...

, and wax coating to make

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 P ...

s and

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 ...

. Biopolymer coatings are available as more sustainable alternatives to common

petrochemical Petrochemicals (sometimes abbreviated as petchems) are the chemical products obtained from petroleum by refining. Some chemical compounds made from petroleum are also obtained from other fossil fuels, such as coal or natural gas, or renewabl ...

coatings like LDPE (see plastic-coated paper) or mylar.

Others

Printed papers commonly have a top coat of a protective polymer to seal the print, provide scuff resistance, and sometimes gloss. Some coatings are processed by UV curing for stability. A release liner is a paper (or film) sheet used to prevent a sticky surface from adhering. It is coated on one or both sides with a release agent. Heat printed papers such as receipts are coated with a chemical mixture, which often contains estrogenic and carcinogenic poisons, such as

BPA BPA may refer to: Organizations *BPA Worldwide, an organization that audits circulation figures for mass media *Banca Privada d'Andorra * Bangladesh Police Academy *Blue Panorama Airlines, ICAO code *Bonneville Power Administration, a U.S. powe ...

. It is possible to check whether a piece of paper is thermographically coated, as it will turn black from friction or heat. (see thermal paper) Paper labels are often coated with adhesive (pressure sensitive of gummed) on one side and coated with printing or graphics on the other.

Varieties

Machine-finished coated paper

Coated fine paper

Plastic coatings

Others

See also

References

Further reading