Lacquer
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225862677
2008-07-15T19:19:41Z
216.184.82.57
/* Japanning */
[[Image:Lacquerware-roundbox-w-children.jpg|thumb|300px|right|A round red [[lacquerware]] box depicting carved scenes of children playing, from the reign of the [[Qianlong Emperor]] ([[1735]]-[[1796]]), [[Qing Dynasty]] of [[China]].]]
In a general sense, '''lacquer''' is a clear or colored [[varnish]], 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]] to high [[gloss]] and that can be further polished as required.
The term ''lacquer'' originates from the portuguese word for [[lac]], a type of resin excreted from certain insects<ref>lacquer. Dictionary.com. The American Heritage® Dictionary of the English Language, Fourth Edition. Houghton Mifflin Company, 2004. http://dictionary.reference.com/browse/lacquer (accessed: May 05, 2008)</ref>. Regardless, in modern usage, lac-based varnishes are refered to as [[shellac]], while lacquer refers to other [[polymers]] dissolved in [[Volatile Organic Compound]]s (VOCs), such as [[nitrocellulose]] and later [[Polymethyl methacrylate|acrylic]] compounds dissolved in a solvent generally referred to as ''lacquer thinner''.<ref>[http://www.minwax.com/products/oil_based_clear_protective_finishes/clear_brushing_lacquer.cfm Minwax® Clear Brushing Lacquer - Oil-Based Clear Protective Finishes - Minwax.com<!-- Bot generated title -->]</ref>
While both lacquer and shellac are traditional finishes, lacquer is more durable than shellac.
==Urushiol-based lacquers==
True lacquerwork is Chinese or Japanese in origin.<ref>[http://www.britannica.com/ebc/article-9369585]</ref> According to ''[[Encyclopædia Britannica]]'', varnish resin derived from a tree indigenous to China, species [[Rhus verniciflua]], commonly known as the varnish tree (q.v.). The manufacturing process was introduced into Japan and remained secret for centuries.<ref>[http://www.britannica.com/eb/article-9057370/Oriental-lacquer]</ref> 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]], a mixture of various phenols suspended in water, plus a few proteins.
[[Image:Colouredwhisles.JPG|right|thumb|Wooden lacquer-finished [[whistle]]s made in [[Channapatna]], [[Karnataka]], [[India]]]]
[[Urushiol]]-based lacquers differ from most other lacquers in that they are slow-drying, water based, and set by [[oxidation]] and [[polymer]]isation, rather than by [[evaporation]] 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 and fairly resistant to mechanical stress. Lacquer skills became very highly developed in India and Asia, and many highly decorated pieces were produced. The process of lacquer application in India is different from China and Japan. There are two types of lacquer: one is obtained from the Rhus 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. Insect lac was introduced to India from Persia (Iran). The fresh resin from the Rhus trees causes [[urushiol-induced contact dermatitis]] and great care is required in its use. The Chinese treated the allergic reaction with shell-fish.
The contemporary theory held that from China, knowledge of lacquer technology was introduced to [[Korea]], and from there to Japan. It was believed that Japan had also been using lacquer from ancient times, but the systematic process of application was developed by the Chinese. With the discovery of lacquer ware in Japan dating back to [[Jōmon period]], conflicting theories claim that technology may have been independently developed in Japan. Trade of lacquer objects traveled through various routes to the [[Middle East]]. Known applications of lacquer in China included coffins, plates, music instruments and furniture. Lacquer mixed with powdered [[cinnabar]] is used to produce the traditional red lacquerware from China.
[[Image:Lacquer.jpg|right|thumb|Lacquer mixed with water and [[turpentine]], ready for applying to surface.]]
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 (called "furo" or "muro" in Japanese, means "a bath" or "a room") 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 ''Rhus 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]]s, giving red or black depending on the oxide. There is some evidence that its use is even older than 8,000 years from archeological 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]], the lacquer is mixed with deer horn powder (or ceramic powder) to give it more strength so it can stand up to the fingering.
[[Image:Chu State Lacquer Coffin.JPG|thumb|right|A Chinese lacquer [[coffin]] decorated with birds and dragons, from the [[State of Chu]], 4th century BC.]]
There are more than four forms of urushiol which is written as thus:
[[Image:Urushiol.png|100px]]
R = (CH<sub>2</sub>)<sub>14</sub>CH<sub>3</sub> or<br>R = (CH<sub>2</sub>)<sub>7</sub>CH=CH(CH<sub>2</sub>)<sub>5</sub>CH<sub>3</sub> or<br>R = (CH<sub>2</sub>)<sub>7</sub>CH=CHCH<sub>2</sub>CH=CH(CH<sub>2</sub>)<sub>2</sub>CH<sub>3</sub> or<br>R = (CH<sub>2</sub>)<sub>7</sub>CH=CHCH<sub>2</sub>CH=CHCH=CHCH<sub>3</sub> or<br>R = (CH<sub>2</sub>)<sub>7</sub>CH=CHCH<sub>2</sub>CH=CHCH<sub>2</sub>CH=CH<sub>2</sub> and others.
== Influence of Korea in the history of lacquer use ==
Lacquer use and its spread throughout Asia have been facilitated by Korea. One of the oldest lacqued table is found in Korea, which dates back to 4th centruty B.C. Other numerous laquered objects of similar time scale have been found. There is growing evidence that various laquered objects were made and sold throughout the region.
==Nitrocellulose lacquers==
[[Image:Freer 002.jpg|thumb|right|[[Ming Dynasty]] Chinese [[lacquerware]] container, dated 16th century.]]
Quick-drying solvent-based lacquers that contain [[nitrocellulose]], 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]] being the fastest drying and thus most popular. General Motors [[Oakland automobile]] brand automobile was the first (1923) to introduce one of the new fast drying nitrocelluous lacquers, a bright blue, produced by [[DuPont]] under their [[Duco]] 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.
==Acrylic lacquers==
Lacquers using [[Polymethyl methacrylate|acrylic]] resin, a synthetic [[polymer]], were developed in the 1950s. Acrylic resin is colourless, transparent [[thermoplastic]], obtained by the polymerization of derivatives of acrylic acid. Acrylic is also used in [[enamel paint|enamels]], which have the advantage of not needing to be buffed to obtain a shine. Enamels, however, are slow drying. The advantage of acrylic lacquers, which was recognized by General Motors, is an exceptionally fast drying time. The use of lacquers in automobile finishes was discontinued when tougher, more durable, weather and chemical resistant two-component [[polyurethane]] coatings were developed. The system usually consists of a primer, colour coat and clear topcoat, commonly known as clear coat finishes. It is extensively used for wooden finishing.
==Water-based lacquers==
Due to [[health]] 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==
[[Image:Red lacquer tray, Song Dynasty.jpg|thumb|right|200px|A Chinese six-pointed tray, red lacquer over wood, from the Song Dynasty (960–1279), 12th-13th century, Metropolitan Museum of Art.]]
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]]''', involves applying several coats of varnish which are each heat-dried and polished. In the [[Mrs Mary Delaney|18th century]] this type of lacquering gained a large popular following. In the 19th and 20th centuries this lacquering technique evolved into the [[handicraft]] of [[decoupage]].
The English novelist George Eliot mentions a "lacker [sic] box" in her novel Silas Marner.
==Japanese lacquer==
Just as "[[Chinese ceramics|China]]" is a common name for Chinese ceramic, "Japan" is an old name for Japanese [[Lacquerware]] (made from the sap of the [[Lacquer Tree]]) and its European imitations.
==See also==
*[[Lacquerware]]
*[[Varnish]]
==References==
<references />
* {{cite book | author = Kimes, Beverly R., Editor. Clark, Henry A. | title = The Standard Catalog of American Cars 1805-1945 | publisher = Kraus Publications | year = 1996 | id = ISBN 0-87341-428-4}} p.1050
* {{cite book | author = Paolo Nanetti | title = Coatings from A to Z | publisher = Vincentz Verlag, Hannover | year = 2006 | id = ISBN 3-87870-173-X}} - A concise compilation of technical terms. Attached is a register of all German terms with their corresponding English terms and vice versa, in order to facilitate its use as a means for technical translation from one language to the other.
* {{Cite book |first=Marianne |last=Webb |title=Lacquer: Technology and Conservation |publisher=Butterworth Heinemann |date=2000 |isbn=0-7506-4412-5 }} — A Comprehensive Guide to the Technology and Conservation of Asian and European Lacquer
* Michiko, Suganuma. [http://lacquer.tafejapan.com "Japanese lacquer"].
[[Category:Decorative arts]]
[[Category:Chinese art]]
[[Category:Japanese art]]
[[Category:coatings]]
[[Category:Resins]]
[[Category:Traditional Chinese objects]]
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