Often in the manufacture of dishes, the question arises of what to use as a coating to keep the surface in a state before use, and after that it was easy to wash off food residues without damaging the surface of the dishes. Food varnish has become such a universal remedy. It has found wide application in the food and light industries.
What it is
Varnishes, or as they are also called, varnish dyes, are water-insoluble complex compounds of water-soluble synthetic dyes with aluminum ions. Water insolubility allows them to be used for coloring confectionery and chewing gums, avoiding unwanted staining of the mouth.
Food varnishes are not subject to chemical influences and steadily tolerate direct sunlight, unlike related dyes. They give painted products a clean, bright, dull color. In its manufacture using equipment with a high number of revolutions during rotation, when there is a dissolution of the particles of the tool. These varnishes are allowed for use in the food and light industry in the Russian Federation and the European Union.
Production
The production of food colors and varnishes is a complex process. Depending on the materials used - organic and inorganic - the technology is different. It is mainly based on the mixing of synthetic dyes consisting of water-soluble components with the addition of aluminum ions.
The dispersing mixture is initially prepared, then the semi-finished products are grinded with pigments (synthetic or natural organic oils), this is done to obtain the main color and its shades. Subsequently, the pigment paste is mixed with water dispersible components, then distributed according to the shade and properties, poured into containers for sale to the consumer.
Varieties
There are several varieties of food varnishes .
- Food canning varnish, its preparation is quite complicated and requires high temperatures, after application to the surface, the product is placed in an oven with a temperature of 250 to 400 ° C.
- Food varnishes for construction are mainly used for applying to the surface of tanks and containers, as well as walls and concrete, where products, vegetables, fruits will be stored.
- A special food coloring, which is used for applying to dishes, this food varnish for wooden dishes is widely used on Khokhloma products.
- There is another type of this varnish - environmentally friendly, not produced in Russia, so it is difficult to obtain.
Features of the composition and properties
Food varnishes consist of organic dyes, they also include binding materials, water-dispersed synthetic components. Vinyl chloride organic solvents may also be included .
The main property of food varnishes is durability, after application to the coating they can maintain their integrity for up to 15 years. Varnishes are completely waterproof; they are resistant to mechanical and chemical damage. Easily tolerate electrical and electrostatic effects without harming the health of the consumer, as they are completely chemically inert. Resistant to seawater, acids and alkalis, as well as aggressive gases. Not subject to the effects of fungi, moss and insects, have a wide range of application temperatures from -30 to +60 ° C.
Also food varnishes are not subject to destruction by fire, as they have the property of self-extinguishing. After application, they dry quickly and have no residual smell, after painting even vertical surfaces; do not have streaks, which gives the products an aesthetic appearance.
Application technology
Before applying, the surface must be dried and cleaned of various elements that may interfere with the uniform coating and quick drying of the varnish. Food varnish-dye is applied to the surface with a brush, rollers, and it is also possible to use special equipment (spray guns, sprayers under air pressure). Temperature range when using from-10 to +30 ° C. Before use, be sure to mix thoroughly.
Expert Advice
Specialists who constantly work with food varnishes advise before use to initially study the properties of the coating and its interaction with the environment, which will be stored in a container or room. When applying, do not fill the surface, but evenly distribute. For painting wooden containers or utensils, it is sometimes advised to coat them with a primer beforehand, using the wet grinding method before priming on wood. The workpiece is soaked in water, then the surface is rubbed with an abrasive paper with fine grain until perfect smoothness appears.
To dissolve the varnish and to clean the instrument, the use of special solvents is recommended, such as acetone, methyl ethyl ketone, butyl acetate, ethyl acetate, amyl acetate. The use of solvents such as white spirit, turpentine, gasoline, kerosene, P-646 and P-647 is strictly prohibited.
Application features
Food varnishes have a wide range of applications both in the food industry and in the painting of construction sites where the use of this particular type of varnish is required. A frequently used application is protection against chemical influences. Varnishes provide protection against aggressive gases such as carbon dioxide, nitric oxide and sulfur. A solution of salts, alkalis and acids (hydrochloric, sulfuric and nitric) do not affect the surface on which the food varnish is applied. Food colorants have a protective effect against any chemicals contained in food products that will be stored in containers coated with varnish.
The number of layers depends on the aggressiveness of the environment, as well as on the individual requirements of the customer and according to the technical documentation during the operation of the coating. Varnishes are also used for applying to metal, concrete and wooden coatings, for transportation and storage of liquid and bulk products, such as alcohol, water, wine, juices, milk, flour. Food varnish for wood is the most ideal type of coating, because it is odorless, dries quickly and does not leave streaks. Due to its properties, it is widely used in woodworking.
Sometimes the varnish for food surfaces is covered by sewer and sewer pipes, the internal surfaces of the oil pipeline, water treatment and ventilation systems, as well as heat and water supply. Offshore platforms, chemical workshops, as well as galvanic baths are coated with these varnishes.
Varnishes were also widely used in confectionery and pharmaceuticals. Apply food varnishes and for dishes, they paint wooden spoons and wooden barrels, buckets, which increases their shelf life.