Ла́к: Қабаттама материал және оның түрлері

Liquid or powder coating material which is applied thinly to objects to form a hard finish

items made with lacquer

Lacquer is a type of hard and usually shiny coating or finish applied to materials such as wood or metal. It is most often made from resin extracted from trees and waxes and has been in use since antiquity. Asian lacquerware, which may be called "true lacquer", are objects coated with the treated, dyed and dried sap of Toxicodendron vernicifluum or related trees, applied in several coats to a base that is usually wood. This dries to a very hard and smooth surface layer which is durable, waterproof, and attractive in feel and look. Asian lacquer is sometimes painted with pictures, inlaid with shell and other materials, or carved, as well as dusted with gold and given other further decorative treatments. In modern techniques, lacquer means a range of clear or pigmented coatings that dry by solvent evaporation to produce a hard, durable finish. The finish can be of any sheen level from ultra matte to high gloss, and it can be further polished as required. Lacquer finishes are usually harder and more brittle than oil based or latex paints and are typically used on hard and smooth surfaces. In terms of modern finishing products, finishes based on shellac dissolved in alcohol are often called shellac or lac to distinguish them from synthetic lacquer, often called simply lacquer, which consists of synthetic polymers (such as nitrocellulose, cellulose acetate butyrate ("CAB"), or acrylic resin) dissolved in lacquer thinner, a mixture of various organic solvents. Although synthetic lacquer is more durable than shellac, traditional shellac finishes are nevertheless often preferred for their aesthetic characteristics, as with French polish, as well as their "all natural" and generally food safe ingredients.

The English lacquer is from the archaic French word lacre "a kind of sealing wax", from Portuguese lacre, itself an unexplained variant of Medieval Latin lacca "resinous substance," from Arabic lakk (لك), from Persian lāk , from Hindi lākh (लाख); Prakrit lakkha, 𑀮𑀓𑁆𑀔), itself from the Sanskrit word lākshā (लाक्षा) for lac bug, representing the number one hundred thousand (100,000), used as wood finish in ancient India and neighbouring areas.

Lacquer sheen is a measurement of the shine for a given lacquer. Different manufacturers have their own names and standards for their sheen.

Types of lacquer vary from place to place but they can be divided into unprocessed and processed categories. The basic unprocessed lacquer is called raw lacquer (生漆: ki urushi in Japanese, shengqi in Chinese). This is directly from the tree itself with some impurities filtered out. Raw lacquer has a water content of around 25% and appears in a light brown colour. This comes in a standard grade made from Chinese lacquer, which is generally used for ground layers by mixing with a powder, and a high quality grade made from Japanese lacquer called kijomi urushi (生正味漆) which is used for the last finishing layers. The processed form (in which the lacquer is stirred continuously until much of the water content has evaporated) is called guangqi (光漆) in Chinese but comes under many different Japanese names depending on the variation, for example, kijiro urushi (木地呂漆) is standard transparent lacquer sometimes used with pigments and kuroroiro urushi (黒呂色漆) is the same but pre mixed with iron hydroxide to produce a black coloured lacquer. Nashiji urushi (梨子地漆) is the transparent lacquer but mixed with gamboge to create a yellow tinged lacquer and is especially used for the sprinkled gold technique. These lacquers are generally used for the middle layers. Japanese lacquers of this type are generally used for the top layers and are prefixed by the word jo (上) which means 'top (layer)'. Processed lacquers can have oil added to them to make them glossy, for example, shuai urushi (朱合漆) is mixed with linseed oil. Other specialist lacquers include ikkake urushi (釦漆) which is thick and used mainly for applying gold or silver leaf.

Solvent based dipping lacquers that contain nitrocellulose, a resin obtained from the nitration of cotton and other cellulosic materials, debuted in the 19th century along with nitrocellulose's other commercial applications. They were used, for example, on brass items such as musical instruments. Faster drying and more durable versions of these lacquers were developed in the early 1920s, when the end of the WWI caused a massive overcapacity of nitrocellulose production, and soon greatly displaced much use of the slower drying paints and lacquers that preceded them; they were extensively used in the automotive industry and others for the next 30 years until further chemical advancements replaced them. Prior to their introduction, mass produced automotive finishes were limited in colour, damaged easily, and took a long time to dry, with Japan black being the fastest drying and thus the most economical to use. The problem with using nitrocellulose in lacquers was its high viscosity, which necessitated dilution of the product with large amounts of thinner for application, leaving only a very thin film of finish not durable enough for outdoor use. This problem was overcome by decreasing the viscosity of the polymer (the term actually post dates the empirical solution, with Staudinger's modern structural theory explaining polymer solution viscosity by length of molecular chains not yet experimentally proven in 1920s) with heat treatments, either with 2% of mineral acid or in an autoclave at considerable pressure. The first practical nitrocellulose enamel Glossy White S.2567, still for interior use, was introduced in 1919 in the UK by Nobel Explosives. In 1923, General Motors' Oakland brand automobile was the first to introduce one of the new fast drying nitrocellulose lacquers, a bright blue, produced by DuPont under their Duco tradename. As Asian lacquer work became popular in England, France, the Netherlands, and Spain in the 17th century, the Europeans developed imitation techniques. The European technique, which is used on furniture and other objects, uses finishes 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 18th century, japanning gained a large popular following. Although traditionally a pottery and wood coating, japanning was the popular (mostly black) coating of the accelerating metalware industry. By the twentieth century, the term was freely applied to coatings based on various varnishes and lacquers besides the traditional shellac.