Lacquer

Lacquer

Overview
In a general sense, lacquer is a somewhat imprecise term for a clear or coloured varnish
Varnish
Varnish is a transparent, hard, protective finish or film primarily used in wood finishing but also for other materials. Varnish is traditionally a combination of a drying oil, a resin, and a thinner or solvent. Varnish finishes are usually glossy but may be designed to produce satin or semi-gloss...

 that dries by solvent evaporation and often a curing process as well that produces a hard, durable finish, in any sheen level from ultra matte
Matte
Matte may refer to:In film:* Matte , filmmaking and video production technology* Matte painting, a process of creating sets used in film and video* Matte box, a camera accessory for controlling lens glare...

 to high gloss
Gloss (material appearance)
Gloss is an optical property, which is based on the interaction of light with physical characteristics of a surface. It is actually the ability of a surface to reflect light into the specular direction. The factors that affect gloss are the refractive index of the material, the angle of incident...

 and that can be further polished as required. It is also used for "lacquer paint", which typically denotes a paint that dries to a more than usually hard and smooth surface.

The term lacquer originates from the Portuguese
Portuguese language
Portuguese is a Romance language that arose in the medieval Kingdom of Galicia, nowadays Galicia and Northern Portugal. The southern part of the Kingdom of Galicia became independent as the County of Portugal in 1095...

 word for lac
Lac
Lac is the scarlet resinous secretion of a number of species of insects, namely some of the species of the genera Metatachardia, Laccifer, Tachordiella, Austrotacharidia, Afrotachardina, and Tachardina of the superfamily Coccoidea, of which the most commonly cultivated species is Kerria lacca.The...

, a type of resin excreted from certain insects.
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Encyclopedia
In a general sense, lacquer is a somewhat imprecise term for a clear or coloured varnish
Varnish
Varnish is a transparent, hard, protective finish or film primarily used in wood finishing but also for other materials. Varnish is traditionally a combination of a drying oil, a resin, and a thinner or solvent. Varnish finishes are usually glossy but may be designed to produce satin or semi-gloss...

 that dries by solvent evaporation and often a curing process as well that produces a hard, durable finish, in any sheen level from ultra matte
Matte
Matte may refer to:In film:* Matte , filmmaking and video production technology* Matte painting, a process of creating sets used in film and video* Matte box, a camera accessory for controlling lens glare...

 to high gloss
Gloss (material appearance)
Gloss is an optical property, which is based on the interaction of light with physical characteristics of a surface. It is actually the ability of a surface to reflect light into the specular direction. The factors that affect gloss are the refractive index of the material, the angle of incident...

 and that can be further polished as required. It is also used for "lacquer paint", which typically denotes a paint that dries to a more than usually hard and smooth surface.

The term lacquer originates from the Portuguese
Portuguese language
Portuguese is a Romance language that arose in the medieval Kingdom of Galicia, nowadays Galicia and Northern Portugal. The southern part of the Kingdom of Galicia became independent as the County of Portugal in 1095...

 word for lac
Lac
Lac is the scarlet resinous secretion of a number of species of insects, namely some of the species of the genera Metatachardia, Laccifer, Tachordiella, Austrotacharidia, Afrotachardina, and Tachardina of the superfamily Coccoidea, of which the most commonly cultivated species is Kerria lacca.The...

, a type of resin excreted from certain insects. In terms of modern products, lac-based varnishes are referred to as shellac
Shellac
Shellac is a resin secreted by the female lac bug, on trees in the forests of India and Thailand. It is processed and sold as dry flakes , which are dissolved in ethyl alcohol to make liquid shellac, which is used as a brush-on colorant, food glaze and wood finish...

, while lacquer refers to other polymers dissolved in volatile organic compound
Volatile organic compound
Volatile organic compounds are organic chemicals that have a high vapor pressure at ordinary, room-temperature conditions. Their high vapor pressure results from a low boiling point, which causes large numbers of molecules to evaporate or sublimate from the liquid or solid form of the compound and...

s (VOCs), such as nitrocellulose
Nitrocellulose
Nitrocellulose is a highly flammable compound formed by nitrating cellulose through exposure to nitric acid or another powerful nitrating agent. When used as a propellant or low-order explosive, it is also known as guncotton...

, and later acrylic compounds dissolved in lacquer thinner, a mixture of several solvents typically containing butyl acetate
Butyl acetate
n-Butyl acetate, also known as butyl ethanoate, is an organic compound commonly used as a solvent in the production of lacquers and other products. It is also used as a synthetic fruit flavoring in foods such as candy, ice cream, cheeses, and baked goods. Butyl acetate is found in many types of...

 and xylene
Xylene
Xylene encompasses three isomers of dimethylbenzene. The isomers are distinguished by the designations ortho- , meta- , and para- , which specify to which carbon atoms the two methyl groups are attached...

 or toluene
Toluene
Toluene, formerly known as toluol, is a clear, water-insoluble liquid with the typical smell of paint thinners. It is a mono-substituted benzene derivative, i.e., one in which a single hydrogen atom from the benzene molecule has been replaced by a univalent group, in this case CH3.It is an aromatic...

. While both lacquer and shellac are traditional finishes, lacquer is more durable than shellac.

In terms of the decorative arts, lacquerware
Lacquerware
Lacquerware are objects decoratively covered with lacquer. The lacquer is sometimes inlaid or carved. Lacquerware includes boxes, tableware, buttons and even coffins painted with lacquer in cultures mostly in the Eastern Hemisphere.-History:...

 refers to variety of techniques used to decorate wood, metal or other surfaces, some involving carving into deep coatings of many layers of lacquer.

Etymology


The French
French language
French is a Romance language spoken as a first language in France, the Romandy region in Switzerland, Wallonia and Brussels in Belgium, Monaco, the regions of Quebec and Acadia in Canada, and by various communities elsewhere. Second-language speakers of French are distributed throughout many parts...

 word lacre "a kind of sealing wax", from Portuguese
Portuguese language
Portuguese is a Romance language that arose in the medieval Kingdom of Galicia, nowadays Galicia and Northern Portugal. The southern part of the Kingdom of Galicia became independent as the County of Portugal in 1095...

 lacre, unexplained variant of lacca "resinous substance", from Arabic lakk, from Persian
Persian language
Persian is an Iranian language within the Indo-Iranian branch of the Indo-European languages. It is primarily spoken in Iran, Afghanistan, Tajikistan and countries which historically came under Persian influence...

 lak, the verb lac meaning "to cover or coat with laqueur". The root of the word is the Sanskrit
Sanskrit
Sanskrit , is a historical Indo-Aryan language and the primary liturgical language of Hinduism, Jainism and Buddhism.Buddhism: besides Pali, see Buddhist Hybrid Sanskrit Today, it is listed as one of the 22 scheduled languages of India and is an official language of the state of Uttarakhand...

 word laksha (लक्ष) meaning "one hundred thousand", which was used for both the Lac
Lac
Lac is the scarlet resinous secretion of a number of species of insects, namely some of the species of the genera Metatachardia, Laccifer, Tachordiella, Austrotacharidia, Afrotachardina, and Tachardina of the superfamily Coccoidea, of which the most commonly cultivated species is Kerria lacca.The...

 insect (because of their enormous number) and the scarlet resinous secretion it produces that was used as varnish in ancient India and neighbouring areas. Lac resin was once imported in sizeable quantity into Europe from India along with Eastern woods. The modern Hindi-Urdu word lakh
Lakh
A lakh is a unit in the Indian numbering system equal to one hundred thousand . It is widely used both in official and other contexts in Pakistan, Bangladesh, India, Maldives, Nepal, Sri Lanka, Myanmar and is often used in Indian English.-Usage:...

(लाख, لاکھ), meaning "hundred thousand," is also derived from the same Sanskrit root-word.

Urushiol-based lacquers



Urushiol
Urushiol
Urushiol is an oily organic allergen found in plants of the family Anacardiaceae, especially Toxicodendron spp. . It causes an allergic skin rash on contact, known as urushiol-induced contact dermatitis...

-based lacquers differ from most others, being slow-drying, water-based, and set by oxidation and polymerization
Polymerization
In polymer chemistry, polymerization is a process of reacting monomer molecules together in a chemical reaction to form three-dimensional networks or polymer chains...

, rather than by evaporation
Evaporation
Evaporation is a type of vaporization of a liquid that occurs only on the surface of a liquid. The other type of vaporization is boiling, which, instead, occurs on the entire mass of the liquid....

 alone. In order for it to set properly it requires humidity and warm temperature. The phenols oxidize and polymerize under the action of an enzyme laccase, yielding a substrate that, upon proper evaporation of its water content, is hard. These lacquers produce very hard, durable finishes that are both beautiful and very resistant to damage by water, acid, alkali or abrasion. The active ingredient of the resin is urushiol
Urushiol
Urushiol is an oily organic allergen found in plants of the family Anacardiaceae, especially Toxicodendron spp. . It causes an allergic skin rash on contact, known as urushiol-induced contact dermatitis...

, a mixture of various phenols suspended in water, plus a few proteins. Varnish resin is derived from a tree indigenous to China, species Toxicodendron vernicifluum, commonly known as the Lacquer Tree. Lacquer skills became very highly developed in Asia, and many highly decorated pieces were produced.

During the Shang Dynasty
Shang Dynasty
The Shang Dynasty or Yin Dynasty was, according to traditional sources, the second Chinese dynasty, after the Xia. They ruled in the northeastern regions of the area known as "China proper" in the Yellow River valley...

 (ca. 1600–1046 BCE), the sophisticated techniques used in the lacquer process were first developed and it became a highly artistic craft, although various prehistoric lacquerware
Lacquerware
Lacquerware are objects decoratively covered with lacquer. The lacquer is sometimes inlaid or carved. Lacquerware includes boxes, tableware, buttons and even coffins painted with lacquer in cultures mostly in the Eastern Hemisphere.-History:...

s have been unearthed in China dating back to the Neolithic
Neolithic
The Neolithic Age, Era, or Period, or New Stone Age, was a period in the development of human technology, beginning about 9500 BC in some parts of the Middle East, and later in other parts of the world. It is traditionally considered as the last part of the Stone Age...

 period and objects with lacquer coating in Japan from the late Jomon period
Jomon period
The is the time in Japanese prehistory from about 14,000 BC to 300 BC.The term jōmon means "cord-patterned" in Japanese. This refers to the pottery style characteristic of the Jōmon culture, and which has markings made using sticks with cords wrapped around them...

. The earliest extant lacquer object, a red wooden bowl, was unearthed at a Hemudu culture
Hemudu culture
The Hemudu culture was a Neolithic culture that flourished just south of the Hangzhou Bay in Jiangnan in modern Yuyao, Zhejiang, China. The site at Hemudu, 22 km north-west of Ningbo, was discovered in 1973...

 (ca. 5000-4500 BCE) site in China.Wang, Zhongshu. (1982). Han Civilization. Translated by K.C. Chang and Collaborators. New Haven and London: Yale University Press. Page 80. ISBN 0300027230. By the Han Dynasty
Han Dynasty
The Han Dynasty was the second imperial dynasty of China, preceded by the Qin Dynasty and succeeded by the Three Kingdoms . It was founded by the rebel leader Liu Bang, known posthumously as Emperor Gaozu of Han. It was briefly interrupted by the Xin Dynasty of the former regent Wang Mang...

 (206 BCE – 220 CE), many centres of lacquer production became firmly established. The knowledge of the Chinese methods of the lacquer process spread from China during the Han
Han Dynasty
The Han Dynasty was the second imperial dynasty of China, preceded by the Qin Dynasty and succeeded by the Three Kingdoms . It was founded by the rebel leader Liu Bang, known posthumously as Emperor Gaozu of Han. It was briefly interrupted by the Xin Dynasty of the former regent Wang Mang...

, Tang
Tang Dynasty
The Tang Dynasty was an imperial dynasty of China preceded by the Sui Dynasty and followed by the Five Dynasties and Ten Kingdoms Period. It was founded by the Li family, who seized power during the decline and collapse of the Sui Empire...

 and Song
Song Dynasty
The Song Dynasty was a ruling dynasty in China between 960 and 1279; it succeeded the Five Dynasties and Ten Kingdoms Period, and was followed by the Yuan Dynasty. It was the first government in world history to issue banknotes or paper money, and the first Chinese government to establish a...

 dynasties, eventually it was introduced to Korea
Korea
Korea ) is an East Asian geographic region that is currently divided into two separate sovereign states — North Korea and South Korea. Located on the Korean Peninsula, Korea is bordered by the People's Republic of China to the northwest, Russia to the northeast, and is separated from Japan to the...

, Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

, Southeast and South Asia. The manufacturing process was introduced into Japan and remained secret for centuries.

The process of lacquer application in India is different from that which is followed in China and Japan. There are two types of lacquer: one obtained from the T. vernicifluum tree and the other from an insect. In India the insect lac was once used from which a red dye was first extracted, later what was left of the insect was a grease that was used for lacquering objects. The fresh resin from the T. vernicifluum trees causes urushiol-induced contact dermatitis
Urushiol-induced contact dermatitis
Urushiol-induced contact dermatitis is the medical name given to allergic rashes produced by the oil urushiol, which is contained in various plants, including the plants of the genus Toxicodendron , other plants in the family Anacardiaceae Urushiol-induced contact dermatitis (also called...

 and great care is required in its use. The Chinese treated the allergic reaction with shell-fish.

Trade of lacquer objects travelled through various routes to the Middle East
Middle East
The Middle East is a region that encompasses Western Asia and Northern Africa. It is often used as a synonym for Near East, in opposition to Far East...

. Known applications of lacquer in China included coffins, music instruments, furniture, and various household items. Lacquer mixed with powdered cinnabar
Cinnabar
Cinnabar or cinnabarite , is the common ore of mercury.-Word origin:The name comes from κινναβαρι , a Greek word most likely applied by Theophrastus to several distinct substances...

 is used to produce the traditional red lacquerware from China.

The trees must be at least 10 years old before cutting to bleed the resin. It sets by a process called "aqua-polymerization", absorbing oxygen to set; placing in a humid environment allows it to absorb more oxygen from the evaporation of the water.

Lacquer-yielding trees in Thailand, Vietnam, Burma and Taiwan, called Thitsi, are slightly different; they do not contain urushiol, but similar substances called "laccol" or "thitsiol". The end result is similar but softer than the Chinese or Japanese lacquer. Unlike Japanese and Chinese Toxicodendron verniciflua resin, Burmese lacquer does not cause allergic reactions; it sets slower, and is painted by craftsmen's hands without using brushes.

Raw lacquer can be "coloured" by the addition of small amounts of iron oxide
Iron oxide
Iron oxides are chemical compounds composed of iron and oxygen. All together, there are sixteen known iron oxides and oxyhydroxides.Iron oxides and oxide-hydroxides are widespread in nature, play an important role in many geological and biological processes, and are widely utilized by humans, e.g.,...

s, giving red or black depending on the oxide. There is some evidence that its use is even older than 8,000 years from archaeological digs in China. Later, pigments were added to make colours. It is used not only as a finish, but mixed with ground fired and unfired clays applied to a mould with layers of hemp cloth, it can produce objects without need for another core like wood. The process is called "kanshitsu" in Japan. Advanced decorative techniques using additional materials such as gold and silver powders and flakes ("makie") were refined to very high standards in Japan also after having been introduced from China. In the lacquering of the Chinese musical instrument, the guqin
Guqin
The guqin is the modern name for a plucked seven-string Chinese musical instrument of the zither family...

, the lacquer is mixed with deer horn powder (or ceramic powder) to give it more strength so it can stand up to the fingering.

There are more than four forms of urushiol which is written as thus:


R = (CH2)14CH3 or
R = (CH2)7CH=CH(CH2)5CH3 or
R = (CH2)7CH=CHCH2CH=CH(CH2)2CH3 or
R = (CH2)7CH=CHCH2CH=CHCH=CHCH3 or
R = (CH2)7CH=CHCH2CH=CHCH2CH=CH2 and others.

Nitrocellulose lacquers


Quick-drying solvent-based lacquers that contain nitrocellulose
Nitrocellulose
Nitrocellulose is a highly flammable compound formed by nitrating cellulose through exposure to nitric acid or another powerful nitrating agent. When used as a propellant or low-order explosive, it is also known as guncotton...

, a resin obtained from the nitration of cotton and other cellulostic materials, were developed in the early 1920s, and extensively used in the automobile industry for 30 years. Prior to their introduction, mass produced automotive finishes were limited in colour, with Japan Black
Japan Black
Japan black is a lacquer or varnish suitable for many substrates but known especially for its use on iron and steel. It is named after Japan. Its high bitumen content provides a protective finish that is durable and dries quickly...

 being the fastest drying and thus most popular. General Motors Oakland automobile
Oakland automobile
The Oakland was a brand of automobile manufactured between 1907–1909 by the Oakland Motor Car Company of Pontiac, Michigan, and between 1909 and 1931 by the Oakland Motors Division of General Motors Corporation. Oakland's principal founder was Edward M...

 brand automobile was the first (1923) to introduce one of the new fast drying nitrocelluous lacquers, a bright blue, produced by DuPont
DuPont
E. I. du Pont de Nemours and Company , commonly referred to as DuPont, is an American chemical company that was founded in July 1802 as a gunpowder mill by Eleuthère Irénée du Pont. DuPont was the world's third largest chemical company based on market capitalization and ninth based on revenue in 2009...

 under their Duco
Duco
Duco was a trade name assigned to a product line of automotive lacquer developed by the DuPont Company in the 1920s. Under the Duco brand, DuPont introduced the first quick drying multi-color line of nitrocellulose lacquers made especially for the automotive industry...

 tradename.

These lacquers are also used on wooden products, furniture primarily, and on musical instruments and other objects. The nitrocellulose and other resins and plasticizers are dissolved in the solvent, and each coat of lacquer dissolves some of the previous coat. These lacquers were a huge improvement over earlier automobile and furniture finishes, both in ease of application, and in colour retention. The preferred method of applying quick-drying lacquers is by spraying, and the development of nitrocellulose lacquers led to the first extensive use of spray guns. Nitrocellulose lacquers produce a very hard yet flexible, durable finish that can be polished to a high sheen. Drawbacks of these lacquers include the hazardous nature of the solvent, which is flammable, volatile and toxic; and the handling hazards of nitrocellulose in the lacquer manufacturing process. Lacquer grade of soluble nitrocellulose is closely related to the more highly nitrated form which is used to make explosives. They become relatively non-toxic after approximately a month since at this point, the lacquer has evaporated most of the solvents used in its production.

Acrylic lacquers


Lacquers using acrylic resin, a synthetic polymer, were developed in the 1950s. Acrylic resin is colourless, transparent thermoplastic
Thermoplastic
Thermoplastic, also known as a thermosoftening plastic, is a polymer that turns to a liquid when heated and freezes to a very glassy state when cooled sufficiently...

, obtained by the polymerization of derivatives of acrylic acid
Acrylic acid
Acrylic acid is an organic compound with the formula CH2=CHCO2H. It is the simplest unsaturated carboxylic acid, consisting of a vinyl group connected directly to a carboxylic acid terminus. This colorless liquid has a characteristic acrid or tart smell. It is miscible with water, alcohols,...

. Acrylic is also used in enamel paint
Enamel paint
Enamel paint is paint that air dries to a hard, usually glossy, finish, used for coating surfaces that are outdoors or otherwise subject to hard wear or variations in temperature; it should not be confused with decorated objects in "painted enamel", where vitreous enamel is applied with brushes and...

s, which have the advantage of not needing to be buffed to obtain a shine. Enamels, however, are slow drying. The advantage of acrylic lacquer is its exceptionally fast drying time. The use of lacquers in automobile finishes was discontinued when tougher, more durable, weather- and chemical-resistant two-component polyurethane
Polyurethane
A polyurethane is any polymer composed of a chain of organic units joined by carbamate links. Polyurethane polymers are formed through step-growth polymerization, by reacting a monomer with another monomer in the presence of a catalyst.Polyurethanes are...

 coatings were developed. The system usually consists of a primer, colour coat and clear topcoat, commonly known as clear coat finishes.

Water-based lacquers


Due to health
Health
Health is the level of functional or metabolic efficiency of a living being. In humans, it is the general condition of a person's mind, body and spirit, usually meaning to be free from illness, injury or pain...

 risks and environmental considerations involved in the use of solvent-based lacquers, much work has gone in to the development of water-based lacquers. Such lacquers are considerably less toxic and more environmentally friendly, and in many cases, produce acceptable results. More and more water-based coloured lacquers are replacing solvent-based clear and coloured lacquers in underhood and interior applications in the automobile and other similar industrial applications. Water based lacquers are used extensively in wood furniture finishing as well.

Japanning


Just as china is a common name for porcelain
Porcelain
Porcelain is a ceramic material made by heating raw materials, generally including clay in the form of kaolin, in a kiln to temperatures between and...

, japanning is an old name to describe the European technique to imitate Asian lacquerware
Lacquerware
Lacquerware are objects decoratively covered with lacquer. The lacquer is sometimes inlaid or carved. Lacquerware includes boxes, tableware, buttons and even coffins painted with lacquer in cultures mostly in the Eastern Hemisphere.-History:...

. As Asian and Indian lacquer work became popular in England, France, the Netherlands, and Spain in the 17th century the Europeans developed imitations that were effectively a different technique of lacquering. The European technique, which is used on furniture and other objects, uses varnishes that have a resin base similar to shellac. The technique, which became known as japanning
Japanning
Japanning describes the European imitation of Asian lacquerwork, originally used on furniture. The word originated in the 17th century.- Japanned :Japanned is most often a heavy black lacquer, almost like enamel paint...

, involves applying several coats of varnish which are each heat-dried and polished. In the 18th century this type of lacquering gained a large popular following.