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 octahedral ...
,
calcium carbonate,
bentonite
Bentonite () is an absorbent swelling clay consisting mostly of montmorillonite (a type of smectite) which can either be Na-montmorillonite or Ca-montmorillonite. Na-montmorillonite has a considerably greater swelling capacity than Ca-mon ...
, and
talc
Talc, or talcum, is a Clay minerals, clay mineral, composed of hydrated magnesium silicate with the chemical formula Mg3Si4O10(OH)2. Talc in powdered form, often combined with corn starch, is used as baby powder. This mineral is used as a thi ...
, 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. Chalk ...
or
china clay
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 octahedral ...
is bound to the paper with synthetic s, such as
styrene-butadiene
Styrene-butadiene or styrene-butadiene rubber (SBR) describe families of synthetic rubbers derived from styrene and butadiene (the version developed by Goodyear is called Neolite). These materials have good abrasion resistance and good aging st ...
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 diets ...
. 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 settl ...
s,
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 natu ...
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 bo ...
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 strength, tens ...
to the paper, or to
protect against ultraviolet radiation.
Varieties
Machine-finished coated paper
''Machine-finished coated paper'' (MFC) has a
basis weight
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), regardless ...
of 48–80 g/m
2. They have good surface properties, high print gloss and adequate sheet stiffness. MFC papers are made of 60–85%
groundwood
House of Anansi Press is a Canadian publishing company, founded in 1967 by writers Dennis Lee and Dave Godfrey. The company specializes in finding and developing new Canadian writers of literary fiction, poetry, and non-fiction.
History
Anans ...
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 compo ...
content of 20–30%. The paper can be soft nip
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 calende ...
ed 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, lea ...
.
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 t ...
:
; Standard coated fine papers: This paper quality is normally used for
advertising material
Advertising is the practice and techniques employed to bring attention to a product or service. Advertising aims to put a product or service in the spotlight in hopes of drawing it attention from consumers. It is typically used to promote a ...
s, books,
annual reports
An annual report is a comprehensive report on a company's activities throughout the preceding year. Annual reports are intended to give shareholders and other interested people information about the company's activities and financial performance. ...
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), regardle ...
ranges from 90–170 g/m
2 and
ISO brightness between 80–96%. The fibre furnish consists of more than 90%
chemical 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 mater ...
. 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 compo ...
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/m
2/side) and the grammage and pigment content are also generally lower, 55–135 g/m
2 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/m
2. These papergrades are triple coated with 20–40 g/m
2/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 perce ...
.
Plastic coatings
Plastic-coated paper Plastic-coated paper is a coated or laminated composite material made of paper or paperboard with a plastic layer or treatment on a surface. This type of coated paper is most used in the food and drink packaging industry.
Function
The plastic is us ...
includes types of paper coatings;
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 bo ...
or
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
Extrusion coating is the coating of a molten web of synthetic resin onto a substrate material. It is a versatile coating technique used for the economic application of various plastics, notably polyethylene, onto paperboard, corrugated fiberboa ...
,
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, cooking ...
, and
wax
Waxes are a diverse class of organic compounds that are lipophilic, malleable solids near ambient temperatures. They include higher alkanes and lipids, typically with melting points above about 40 °C (104 °F), melting to giv ...
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
Paper ...
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 v ...
.
Biopolymer
Biopolymers are natural polymers produced by the cells of living organisms. Like other polymers, biopolymers consist of monomeric units that are covalently bonded in chains to form larger molecules. There are three main classes of biopolymers, cl ...
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 renewable sou ...
coatings like
LDPE
Low-density polyethylene (LDPE) is a thermoplastic made from the monomer ethylene. It was the first grade of polyethylene, produced in 1933 by Imperial Chemical Industries (ICI) using a high pressure process via free radical polymerization. Its ...
(see
plastic-coated paper Plastic-coated paper is a coated or laminated composite material made of paper or paperboard with a plastic layer or treatment on a surface. This type of coated paper is most used in the food and drink packaging industry.
Function
The plastic is us ...
) or
mylar
BoPET (biaxially-oriented polyethylene terephthalate) is a polyester film made from stretched polyethylene terephthalate (PET) and is used for its high tensile strength, chemical and dimensional stability, transparency, reflectivity, gas and aro ...
.
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
UV curing (ultraviolet curing) is the process by which ultraviolet light is used to initiate a photochemical reaction that generates a crosslinked network of polymers. UV curing is adaptable to printing, coating, decorating, stereolithography, an ...
for stability.
A
release liner
A release liner or ''release paper'' is a paper or plastic-based film sheet (usually applied during the manufacturing process) used to prevent a sticky surface from prematurely adhering. It is coated on one or both sides with a release agent, whic ...
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
A release agent (also mold release agent, release coating, or mold release coating) is a chemical used to prevent other materials from bonding to surfaces. It can provide a solution in processes involving mold release, die-cast release, plastic re ...
.
Heat printed papers such as receipts are coated with a chemical mixture, which often contains estrogenic and carcinogenic poisons, such as
BPA. 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
A thermal column (or thermal) is a rising mass of buoyant air, a convective current in the atmosphere, that transfers heat energy vertically. Thermals are created by the uneven heating of Earth's surface from solar radiation, and are an example ...
)
Paper
label
A label (as distinct from signage) is a piece of paper, plastic film, cloth, metal, or other material affixed to a container or product, on which is written or printed information or symbols about the product or item. Information printed dir ...
s are often coated with adhesive (pressure sensitive of gummed) on one side and coated with printing or graphics on the other.
See also
*
Gloss Paper, is encrusted with smoothness
*
Carbon paper
Carbon paper (originally carbonic paper) consists of sheets of paper which create one or more copies simultaneously with the creation of an original document when inscribed by a typewriter or ballpoint pen.
History
In 1801, Pellegrino Turri, ...
*
Folding box board
*
Inkjet paper
Inkjet paper is a special fine paper designed for inkjet printers, typically classified by its weight, brightness and smoothness, and sometimes by its opacity.
Manufacture
Some inkjet papers are made from high quality deinked pulp or chemical ...
*
Paperboard
Paperboard is a thick paper-based material. While there is no rigid differentiation between paper and paperboard, paperboard is generally thicker (usually over 0.30 mm, 0.012 in, or 12 Inch#equivalences, points) than paper and has certain ...
*
Paper 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 Machin ...
*
Paper making
Papermaking is the manufacture of paper and cardboard, which are used widely for printing, writing, and packaging, among many other purposes. Today almost all paper is made using industrial machinery, while handmade paper survives as a speciali ...
*
Plastic-coated paper Plastic-coated paper is a coated or laminated composite material made of paper or paperboard with a plastic layer or treatment on a surface. This type of coated paper is most used in the food and drink packaging industry.
Function
The plastic is us ...
*
Solid bleached board
Solid bleached board (SBB) or solid bleached sulphate (SBS) is a virgin fibre grade of paperboard.
This grade is made purely from bleached chemical pulp and usually has a mineral or synthetic pigment coated top surface in one or more layers (C1S) ...
*
Solid unbleached board
Solid unbleached board, also known as SUB, is a grade of paperboard typically made of unbleached chemical pulp. Most often it comes with two to three layers of mineral or synthetic pigment coating on the top and one layer on the reverse side. Re ...
*
Thermal paper
A thermal column (or thermal) is a rising mass of buoyant air, a convective current in the atmosphere, that transfers heat energy vertically. Thermals are created by the uneven heating of Earth's surface from solar radiation, and are an example ...
*
Tracing paper
Tracing paper is paper made to have low opacity, allowing light to pass through. It was originally developed for architects and design engineers to create drawings that could be copied precisely using the diazo copy process; it then found ma ...
*
White-lined chipboard
*
Waxed 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-proo ...
References
Further reading
* Soroka, W, "Fundamentals of Packaging Technology", IoPP, 2002,
* Yam, K. L., "Encyclopedia of Packaging Technology", John Wiley & Sons, 2009,
{{Paper
Packaging materials
Paper
Papermaking
Chemical processes