What is a varnish: What Is Varnish? – Our Guide to Protective Surface Treatments

They are paints used for the treatment of masonry walls. Water instead of oil is used as a vehicle ► known as water-paint too. Powdered white chalk and glue boiled in water are mixed. Usually colored by mixing different pigments. All Distempers mixed with water only before being used. Distemper affected by weathering condition and takes off if washed ► to be used only in interior works. Cheap, durable and easy interior finish. Should be applied on clean and dry surface.

Varnish | it’s… What’s Lak?

This term has other meanings, see Varnish (meanings).

Lacquer is a solution of artificially synthesized or natural organic polymers (resins), in various organic solvents or water. It cures to a clear, glossy or matt film. Currently, there are varnishes that do not contain solvents. Their low viscosity is provided by oligomers that are able to cure in the presence of special substances – hardeners or catalysts. Varnishes are conditionally divided into thermoplastic and thermosetting. The curing of the lacquer film occurs either by evaporation of the solvent or by a chemical polymerization reaction.

Varnishes are solutions of solids in liquids that can either evaporate or dry out; solid substances are various resins, and ethyl (wine) and methyl (wood) alcohols, essential and vegetable drying oils serve as solvent liquids. The resin solution applied to the surface to be varnished dries, leaving a thin, transparent and shiny film (in practice called varnishing), the properties and qualities of which determine the merits of the varnish taken.

In foreign languages ​​words fr. laque German Lack means paint obtained by precipitation of organic color pigments with metal salts. Such paints in Russian are called bakans, and the Russian word “lacquer”, as a designation for a liquid with the above properties, is translated in Western Europe by the words English. varnish German Firniss , fr. vernis .

There are many different resins used in the production of lacquers; they differ from each other in their properties, depending on which the advantages of the obtained varnishes are also located. Almost all resins dissolve in vegetable oils and only a few in essential oils and alcohols. Resins that are particularly hard and infusible are called copals. Of the liquids as solvents in the lacquer industry, the most commonly used are: ordinary alcohol, various varieties of turpentine and linseed oil. According to these solvents, varnishes are divided into three main groups: alcohol varnishes, turpentine and oil varnishes. Each of these groups has its own selection of resins, differs in its characteristic properties and purpose; the production of varnishes of each group requires special techniques and devices. The invention of varnish in Europe is attributed to the German monk Theophilus, who lived in the 12th century; at first, their preparation was surrounded by secrets and was carried out in a cell way. One must think that the first varnishes of European production were alcohol, and the first varnish factory on the European continent should be considered the factory of the French chemist Chenet, built in 1803.

Manufacture of oil varnishes was for a long time the privilege of England, and only when America, Portugal and Holland began to supply European markets with the same resins and copals that England used exclusively from her colonies, varnish production became generally available; however, the emergence of oil and varnish factories began only in the early 60s of the XIX century, that is, it coincides with the publication of research by the French chemist Violet on varnishes in 1862.

In Russia, the beginning of the production of oil carriage varnishes coincided with the development of the railway network. The first Russian plant of high grades of oil varnishes was the plant of the company I. S. Ossovetsky and K ^o , founded in 1874 in Moscow.

Alcohol varnishes

Alcohol varnish is a simple solution of resin in wine or wood alcohol. The latter is used on its own very rarely, but often serves as an admixture of wine alcohol in order to reduce the cost of varnish. Of the resins, sherlac (or shellac), sandarac and mastic are used. The resin is ground into a fine powder and poured with alcohol at 92-95°, in glass bottles or cylinders; dissolution is carried out at room temperature and accelerated by constant shaking. Resin is always taken in excess, in order to obtain a saturated solution. So the prepared varnish is filtered. This operation in the production of alcohol varnishes is considered the most difficult, it is carried out differently at different factories and is carefully guarded from outsiders, being considered the secret of the factories.

Ordinary straining is done with glass funnels lined with felt or cloth strainers; funnels are covered with glasses with small vents for air access. Straining is very slow and is always associated with a loss of alcohol. Alcohol varnishes get their name from the resins on which they are prepared. So, there are varnishes shellac, sandarach and sandarach-shellac. Mastic is not used on its own and serves as an admixture to the named resins. The admixture of mastic softens the varnish film, but increases its shine. Alcohol varnish thinned with alcohol is called varnish. In addition to the divisions mentioned, alcohol varnishes and varnishes also get their names from the color in which they are painted; so known are red, yellow, white and various colored paints and varnishes. Alcohol varnishes are used for varnishing and polishing wooden products. The varnish layer does not tolerate the influence of the external atmosphere and is especially afraid of dampness and sudden changes in temperature; in enclosed spaces, under normal room air conditions, it persists for a long time.

According to the hardness of the layer, the first place belongs to shellac varnishes; sandarach varnishes give a softer varnish, but they always turn out lighter. Colored varnishes are tinted with aniline paints, usually prepared on sandarak with an admixture of mastic, used for varnishing metal products, toys, tin capsules, etc. Their color, due to the instability of aniline pigments, is very fragile.

Turpentine varnishes

Similar to spirit varnishes, they are prepared by simply dissolving resins in turpentine. Turpentine varnishes are divided into white and black; for the preparation of the former, dammar resin is used, for the black ones, asphalt. Dammar varnishes are usually valued for their shade; the lightest, almost white, are called enamel. Dammar varnishes, yellowish, are prepared in three varieties, designated No. 1, 2 and 3, the only difference of which lies in the density of the shade; the lighter the varnish, the more expensive it is and goes under No. 1. The division into grades of asphalt varnishes is done depending on the admixture of rosin (harpius), which serves to reduce the cost of these varnishes to the detriment of their quality. Asphalt varnishes are also available in three grades, referred to in trade Nos. 1, 2 and 3.

The production of turpentine varnishes is usually associated with the production of oil varnishes, while the production of alcohol varnishes has nothing in common with the production of oil and turpentine varnishes. Turpentine varnishes are prepared as follows: dammar resins or asphalt are crushed into pieces the size of a walnut and poured into a copper pot heated on the hearth in this form. At temp. about 200 ° C, dammar and asphalt soften (resins prescribed for turpentine varnishes should not be brought to liquid melting; softened resin is removed from the hearth and poured over in a pot with turpentine, which quickly mixes with the resin, for which you only need to mix them thoroughly with an iron spatula, with a stirrer, and add turpentine in small portions. Usually poured on 10 parts of resin to 30 parts of turpentine by weight. Varnish, thus prepared, is drained in a warm state into settling tanks, where it settles for 2 to 3 weeks, and then enters the trade The use of turpentine varnishes is rather limited; their varnish film is soft, hygroscopic and does not withstand the influence of the external atmosphere.All varieties of dammar varnishes are used for varnishing surfaces painted in white or in the lightest colors. Black, asphalt varnish is used for varnishing cheap iron products or the most simple painting of the same color stains.0003

Oil lacquers

They have the widest and most diverse uses, and therefore their range is very numerous. The materials for the production of oil varnishes are linseed oil, turpentine and various varieties of copals. Linseed oil comes in the form of drying oil, which is harvested earlier. Turpentine is used only of high purity, usually French turpentine is used for lacquer work. and American, obtained in the production of rosin. Of copals – the most important material – all varieties of copal-kauri, copal-manilla, zanzibar, angola, sierra leone and westind copal (crystal) are especially preferred. The quality and merits of oil oils depend on the choice of all the materials mentioned. The production of oil oils is more difficult than alcohol and turpentine ones; in addition, it requires special skill, experience and careful observation. All production consists of the following operations:

1. preparation of drying oil
2. sorting
3. crushing
4. melting copals
5. varnish cooking
6. settling

Lacquer drying oil is prepared from dry, settling linseed oil; the oil is heated to a temperature of 260 ° C in a special copper open cauldron over a bare fire, and during the cooking of drying oil, a little lead sugar and manganese boric acid are added to it. The welded drying oil should dry on the test glass for 18 hours, not stick and be a transparent, colorless, shiny and elastic film. Such drying oil is not only a solvent for copals, but itself serves as the main component of the lacquer shell. Linoxein of drying oil, combining with copals, destroys their fragility, gives elasticity to the varnish film and serves as an important condition for the strength and stability of oil varnishing. Lacquer drying oil is prepared for storage, stored in settling tanks, and only in a clean, settled form is used for the preparation of varnish.

Copal sorting also plays an important role in production. Commercial grades are obtained in pieces of various sizes, varying degrees of transparency and color, and even different hardness. When sorting, pieces are selected that are uniform in color, purity, size and hardness, and each variety separately serves to prepare a special variety or No. L. Crushing of copals is carried out using a manual machine used for chopping sugar; with a certain skill, one person per day can grind about 6 pounds of copal.

The sorted, crushed copal goes to the smelter and then to the smelter. The selection and relative proportion of them for cooking is known. varieties or, as they say, the specialty of L. and is usually the secret of factories. Mixing combinations, due to the huge selection of copals and other resins, are countless, and each plant has its own methods and recipes. Different copals have different hardness and therefore different melting points. There are copals, such as Zanzibar, Sierra Leone, and others, melting above 400 ° C, therefore, when melting, such an order should be observed so that a portion of refractory copal is poured into the melting pots first and after it is melted, the more fusible copals required by the recipes, etc., are added. resins. This precaution reduces the burning of resins and gives lighter shades of L., but in practice, craftsmen almost always mix crushed copals at once and the mixture is subjected to simultaneous melting. Melting and boiling are the most complex and difficult operations in the production of L. When melting copals, an abundant release of volatile products, which are easily flammable, occurs, so the arrangement of lacquer hearths requires special devices. The smelting of copals and the boiling of limes at large factories are carried out in large copper cauldrons with a capacity of 30–40 buckets (370–490 liters) placed on hearths arranged in the floor of the lacquerery. Above the boiler is a funnel-shaped iron cap, with draft, to remove volatile products. The boiler is equipped with a chain, by means of which, with the help of a crane installed nearby, it can be removed from the hearth at any time. Throughout the smelting, the beginning of which is determined by the appearance of heavy vapors and gases in the form of smoke, the copal is stirred with an iron stirrer.

At the end of melting, which is recognized by the cessation of smoke emission, the boiler is removed from the hearth, and a certain portion of drying oil, preheated to 250 ° C, is poured into the melted copal, with constant stirring, in parts; then the boiler is again placed on the hearth and cooking begins. This operation requires special knowledge and experience. All the dignity of L. depends on the definition of the end of its cooking. L. undercooked or overcooked is rejected. The end of cooking is determined by constant samples of boiled L. These samples are made using a glass rod, with which boiled L. is taken in drops on a flat glass, and the end of cooking is recognized by the color, density and stickiness of these drops.

Cooked L. is removed from the hearth and allowed to cool to 200 °C. When this temperature is reached, with constant stirring, a pre-weighed portion of turpentine is poured in parts, and the boiler is placed under a hood with draft, since dilution of L. with turpentine is accompanied by a strong release vapors and gases. Then L. is allowed to cool and the cooled, finished varnish is poured into settling tanks.

At small factories, and some L. and at large factories, they cook in smaller copper pots, the capacity of which does not exceed 4-5 buckets (50-60 liters). For such pots (manual), special hearths are arranged and the pots themselves have a special design with a helmet that removes gases into the exhaust pipe and an opening through which the contents of the pot are constantly mixed with a stirrer. Melting and boiling are carried out in exactly the same way as in large boilers.

The following is considered to be the classic recipe for oil L.: 14 hours of copal, 43 hours of drying oil and 25 hours of turpentine. At the same time, however, it should be noted that the whole essence of lacquer production is the choice and proportion of copals, the specifics of the preparation of drying oil, and the method of melting copals and boiling oil. The sump must be at least 20° R (25° C) and free from moisture. Tanks are made of boiler iron with a capacity of 50 to 100 pd. (820-1640 Kg.) L. For each variety L. must have at least two reservoirs, since settling lasts at least 6 months. The settled L. is poured and soldered into tin gallons, containing from 5 lbs. (2 Kg.) to 1 pd. (16 Kg.) L., in which L. and go on sale. Oil L. are subdivided into carriage, painting and special. Carriage coats are distinguished by: preparatory coats for preparing the surface for painting, coats Nos. 2 and 3 for the first layers of lacquering to be painted for sanding, and sheets Nos. 1 and 0 for the last coats of varnishing of carriages. Of L. painting, we note L. sexual, which are several numbers, in color and quality. They are distinguished by a special hardness of the film and are suitable for varnishing painted floors. L. painting copal, copal-amber – also in several numbers – are intended in general for varnishing on wood and on any color, if gloss is required and if the surface is subject to the influences of the external atmosphere. Of special varnishes, various types of varnishes are of great importance: leather, oilcloth, wallpaper, tin, black Japanese, etc.

Car paints

In essence, car paint is a very clear, highly refined alkyd resin with special additives.

Highest quality HS clearcoat for use in automotive aftermarket and automotive design work. It is a high-transparency lacquer that provides the highest surface quality, excellent brightness and gloss. It is weather resistant, UV resistant, has excellent elasticity and polishes excellently.

Depending on the country of manufacture and the make of the vehicle, varnishes from different manufacturers can be used. It is no secret that in the production of cars in different countries they use different technologies, for example, in the production of their cars, German manufacturers turn to the drying mode in high-temperature chambers, which significantly saves time. But it does not save resources and electricity. But the Japanese auto industry, due to limited resources in terms of geographical location, went the other way, where drying is carried out using a minimum amount of electricity and heat, while the process is accelerated due to chemical catalysis and special chemical drying accelerators.

This varnish has sufficient strength, but some precautions must still be observed. It is strongly not recommended to wipe a dirty car with rags, brushes or other hard devices, especially when it is dry. Also, quite serious problems can be caused by bags, boxes and other items placed on a dirty body, and subsequently removed or moved from it (dust and sand particles, always invisibly present on the car body, will play the role of an abrasive and leave deep scratches on your car which will be difficult to eliminate later).

Building varnishes. General information

Varnishes are a large group of materials that are solutions of film-forming substances (resins or polymers) in organic solvents or water. After drying, they form a solid transparent (colorless or colored) film.

Varnishes are used to obtain transparent coatings when it is necessary to protect and at the same time preserve or emphasize the structure of the surface to be painted, especially valuable woods. In this case, the varnish is applied to the prepared surface of the product. Lacquering as the last layer in a multi-coating system will give it a good appearance and improve performance.

Bituminous varnishes are obtained from bitumen of special grades with the addition of various resins and oils. When dried, bituminous varnishes form a black film that is resistant to water and some chemicals. However, the anti-corrosion properties of the bitumen film in atmospheric conditions are not high enough. Most often, bituminous materials (lacquer BT-577, paints BT-177 and BT-184) are used for temporary protection of metal, since they are much cheaper than other materials.

Oil varnishes are obtained by dissolving natural or artificial resins in drying vegetable oils with the addition of desiccants and solvents. From natural resins, rosin, shellac and amber are more often used. Kopals, dimmaru, sandarak, mastic, akaroid, imported from India and other countries, are used mainly for artistic and decorative painting. Natural resins, except for rosin and amber, are scarce materials and are used to a limited extent. They are replaced by synthetic resins (polymers) – perchlorovinyl, alkyd, inden-coumarone, phenol-formaldehyde, etc.

As a rule, oil varnishes form hard transparent films of a yellowish color. Due to the low weather resistance of the coatings, oil varnishes are used for interior finishing, for example, to give shine to worn wood flooring.

Alkyd lacquers are the most commonly used lacquers in everyday life. They are solutions in organic solvents of synthetic alkyd (pentaphthalic or glyphthalic) resins. Films of alkyd varnishes are hard, transparent, slightly colored; possess good adhesion to various surfaces, water-resistant. Are applied both to internal, and to external works. (Although traditionally lacquers are rarely used outdoors.)

In everyday life, alkyd varnishes are mistakenly called oil varnishes. This is not true because although vegetable oils are used in the manufacture of alkyd resins, alkyd varnishes differ from oil varnishes in chemical composition and structure, and significantly surpass them in properties.

Here are some basic information about the most suitable alkyd varnishes for home use.

Lacquer GF-166 (PF-283) is a solution of alkyd glyphthalic (pentaphthalic) resin modified with vegetable oils in an organic solvent with the addition of NF-1 siccative. Gives a uniform glossy transparent film. It is intended for a covering on oil paints, wooden and metal surfaces outside and in rooms. Apply by brush, roller or spray gun. It is diluted if necessary with white spirit or RS-2 solvent. Varnish consumption for a single-layer coating is 70-75 g/m2. The drying time of a single layer coating is 48 hours.

Lacquer GF-177 is a solution of glyptal resin modified with cottonseed oil in organic solvents with the addition of a siccative. It is intended for coating wooden, primed or painted metal surfaces operated in atmospheric conditions. Also recommended for painting kitchen furniture. Before work, the varnish is diluted with solvents 649, 650, RS-2, solvent or turpentine and filtered through 2 layers of gauze. For preservation, wooden surfaces are recommended to be additionally treated with anti-rotten compounds, filled and painted (for example, stained). Primed or previously painted metal surfaces should be sanded and wiped with mineral spirits. The duration of drying of a single-layer coating is 24 hours, the second layer of varnish is applied with a brush after 36 hours. Consumption of varnish for a single layer coating — 60 — 90 g/m2.

Nitrolacquer (nitrocellulose varnishes) is obtained by dissolving cellulose nitrate in a mixture of active organic solvents. The properties of varnishes are regulated by introducing various resins (alkyd, amino-formaldehyde, etc.) into the composition. Nitro-varnishes form hard transparent, almost colorless quick-drying films. Most often, nitrovarnishes (NTs-221, NTs-222, NTs-218, NTs-228, etc.) are used for varnishing wood products.

Epoxy varnishes are solutions of epoxy resins in organic solvents. Before varnishing, a hardener is added to them, the amount of which depends on the type of resin and hardener, curing conditions and is indicated in the instructions for use. Lacquer films have high water and alkali resistance, mechanical density, adhesion to various materials, but are not weather resistant enough. In everyday life, epoxy varnishes are often used for making putties, gluing, making souvenirs and other purposes.

Alcohol varnishes and varnishes are obtained by dissolving some natural shellac resins, sandarak in alcohol (lacquer concentration 30-45%, varnishes 15-25%). These materials give a coating with good mechanical strength and adhesion to various surfaces, high gloss. Coatings are well polished, but have low water resistance.

Oil and alcohol varnishes are produced in small quantities due to scarce and expensive natural raw materials. They are mainly used for special purposes, for example, in the manufacture of musical instruments.

Petroleum polymer varnishes are a new group of varnishes that are significantly cheaper than oil-resin varnishes, but can replace the latter, surpassing them in resistance to detergents and various reagents.

These varnishes (NP-2129, NP-2130) are obtained in the form of compositions, solutions of petroleum polymer resins in organic solvents with various modifying additives.

Alkyd-carbamide varnishes (MCh-52) are a solution in organic solvents of a composition of alkyd resin with amino-formaldehyde (urea-melamine-formaldehyde) or taken together in a certain ratio. Air-dry at normal temperature only when introduced into them before using a given amount of acid hardeners. With a hardener, the shelf life of the varnish is limited from several hours to several days. Such materials can dry without hardener, but with hot drying (80-120 °C). Alkyd-urea varnishes with hardeners form rather quickly air-drying films, which are distinguished by increased hardness, good water and wear resistance. These varnishes are used to coat parquet floors, furniture and various wood products used indoors.

Polyurethane and alkyd urethane varnishes produce films with exceptionally high mechanical strength and wear resistance. They varnish parquet floors, furniture, musical instruments.

Polyacrylate lacquer AK-156 is a solution of acrylic copolymer in a mixture of organic solvents with the addition of organic dyes. Designed to create a decorative coating on metal, glass and wood of various species. The varnish gives the wood the desired shade and emphasizes its texture, protects the materials from atmospheric influences. Available in various colors: colorless, yellow, orange, red, blue, green, brown.

Stir the varnish thoroughly before application; if necessary, can be thinned with acetone or Thinner 646. Drying time for each coat is 24 hours, for a single coat 60 g/m2 of varnish is required.

Particular attention should be paid to special varnish compositions used to protect wood. These varnishes give the surface a decorative look, while protecting the wood from mold, rot, insect damage and weathering. Available in various colors. Are applied to external and internal works. They can be used on wooden exterior walls, cornices, doors, windows, etc. They reliably protect wood from mold and decay for several years.

See also

• petroleum resins
• Nail polish
• Hairspray

Links

• Additional information about

varnishes

• paint varnishes

When writing this article, material from the Encyclopedic Dictionary of Brockhaus and Efron (1890-1907) was used.

What is Varnish and what types of varnishes are there?

Varnishes are more or less transparent liquids that are used to provide a protective coating to a surface in much the same way that paints do.” At the same time, they allow the original surface to be displayed, but give it a shiny and glossy finish. All varnishes have basically the same components as paints.

What is varnish? Lacquer is a transparent, hard, protective treatment or film, mainly used for woodworking, but also for other materials. Traditionally, lacquer is a combination of drying oil, resin, and a thinner or thinner. Lacquer finishes are usually glossy, but can be designed to achieve satin or semi-gloss hues by adding “flattening” agents.

Varnish types

Natural resin varnishes:

Natural resin body obtained from selected trees. Natural resin obtained from living trees or from fossils. The vehicle in lacquer is the same as in oil-based paint. Resins dissolved in oil ► mixture heated to a temperature (500-600OF), depending on the amount of gloss required. Oil and natural resin varnish ► OLEO RESINOUS varnish. The thinners and dryers used in varnishes are the same as those used in oil-based paints.

Modified natural resin varnishes:

Made from natural resin that has been chemically modified. Regular resin is thermally treated with glycerin to form a gum. This gum is considered as a body for varnish. Less expensive polish than resinous oleo polish.

Synthetic resin varnish :

• Synthetic varnish produced by the plastics industry

• Chemicals used include nitrocellulose, amino resins, silicon, etc.

• Vehicle is most often the same as for oleo tar varnish

• Coal tar derivatives can be used as thinners

• Dryer is also the same as for other types of varnishes
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Lacquer classification

Long oil varnish:

Medium Oil Varnish:

1. Medium Oil contains 12-40 gal oil per 100 pounds of resin
2. They dry faster ► stronger
3. Harder film than pre-oiled lacquer, but impervious to water
4. This group includes floor varnish

Short Oil Resins:

Short Oil contains 5-12 gal of oil per 100 pounds of resin.