Prododzheenie article ... Resin - natural or synthetic compounds that are soluble in certain solvents. Natural resin - gum rosin, shellac, dammar - have a kind of creamy-brown or reddish pebbles scales. Rosin is prepared from resin by distillation of turpentine in its pure form it is almost never used. To use it is treated with glycerin. The product of this process and serves as a raw material for cooked varnishes and paints. Lucky high quality, used mainly for painters, paintings, derived from pistachio tree resin. Shellac - a natural resin, released the young shoots of some plants. It is used for making alcoholic varnishes and lacquers. In addition to alcohol shellac dissolves in alkalis and solutions of borax, forming thus water lakes, which are used as fixatives for the work executed in pencil, charcoal and pastel. Synthetic resins - polyesters, formaldsgidnye, vinyl, epoxy - are in the form of thick plastic compounds or glassy mass, which dissolves under the influence of different solvents. Without the addition of pigments or dyes, these solutions form a variety of paints, but with additions - colorful compositions. Synthetic resins give educated on the basis of their structure, the properties that can not be obtained by applying the natural gums, such as improved thermochemical stability, strength of the resulting film. This explains their widespread use. Melamine-formaldehyde resins with alkyd and respective pigments form a colorful compositions for exterior and for interior works. Colorful compositions based on epoxy resins are mainly used for indoor as well as the sunlight they turn yellow with time. Polyvinyl acetate resins are widely used to allow internal works compiled on the basis of their compositions, creating a dull film. Pitch, bitumen, tar - by-products of chemical raw materials and coal. In conjunction with organic solvents, they form a protective lacquer, but have a low decorative properties, which reduces their use in design works. Nitrocellulose-white fibrous substance, tea by processing cellulose with a mixture of sulfuric and nitric acids. It is a basic material for production of nitrocellulose lacquer and nitroemaley, which lack the high flammability. Solvents - a single-or multi-component organic compound is a liquid used to dissolve the natural and synthetic resins, as well as to bring the ink compositions to a working consistency and dilution of thickened oil-based paints, varnishes and primers. The main requirement for solvents - to be inert in the compounds, ie, not to react with paints or painted surface, be sufficiently volatile for the complete evaporation of the paint layer during its drying. Solvents on the degree of activity is divided into three groups: high, middle and small. To appoint distinguished solvents: for oil-based paints and varnishes; alkyd. pentaphthalic, bituminous paints and varnishes; for epoxy, perchlorovinyl nitrocellulose lacquers and paints. Simple solvents - are organic substances in pure form, used for dissolving films or mixing. These include turpentine, acetone, ethyl acetate, amyl acetate, mineral spirits, solvent coal technology, ethylene dichloride. Turpentine - a colorless or slightly pigmented, clear, flammable liquid (flash point 30-32 ° C) with a characteristic odor. It is produced by dry distillation of pine wood (wood turpentine) or by distillation of the resin of coniferous trees - gum (gum turpentine). Wood turpentine must pass an additional cleaning process which removes it contains coloring matter. Gum turpentine (turps) is more clarity, ease and less pungent odor. Turpentine is not toxic. Its density 0,86-0,875 g/cm3 Turpentine - solvent medium activity. It is used to dissolve the oil, alkyd, alkyd-styrene varnishes and paints, and also for degreasing surfaces (glass, Plexiglas, plastics) for posleduyschey work paint formulations. This - the most expensive solvent, with good quality characteristics. To determine the suitability of turpentine, it is checked for dry mixed with linseed oil. To do this, mix equal amounts of linseed oil and turpentine mixture and make vykrasku. After 24 hours on the painted surface should form a solid film. Acetone, ethyl acetate, amyl acetate - a fairly common solvents. They are well mixed with water, so using them as solvents (nitro lacquer and paints, care should be taken not to get water in their composition, as this happens whitening transparencies. Adding to the composition of these solvents, butyl alcohol (butanol), butyl warns whitening varnish film and enhances its luster. White spirit (or petrol-solvent) - distillate oil, the average fraction between the heavy gasoline I and tractor kerosene. Density is not more than 0.795 g/cm3. White Spirit - a solvent of low activity. His widely used to dilute oil paints. When added to paints, lacquers, varnish is necessary to limit the quantity to 10% of the total weight of the paint composition. Apply white spirit as for dissolution (washing) of the old coating (cured film) of oil paints and varnishes. Solvent Coal Technology - a mixture of hydrocarbons obtained as a by-product coke production in the process of rectification of purified fractions of crude benzene. It is a colorless transparent liquid, density at 20 ° C - 0.865 - 0, 885 g / cm 3 depending on the brand. Our industry produces solvent in three grades (A , B, C) with different density, boiling point, as well as minor fluctuations content of phenols and sulfur. Solvent is a solvent of high activity but slightly reduces the toxicity of its application area. Apply solvent coal for breeding glyptal and nentaftalevyh paints and varnishes, and asphalt and asphalt paint. Dichloroethane - a colorless, slabovosgoraemaya liquid with a characteristic odor of chloroform. For long term storage under the action of sunlight dichloroethane, which is in a transparent bowl, turning yellow. It is used as a solvent of fats, waxes, perchlorovinyl, glyptal and other synthetic resins used as , an adhesive when working with organic glass. If you are using dichloroethane need to follow safety rules, as it irritates the skin. Mixed solvents - a mixture of different simple solvents. obtained in this way, they are much cheaper and higher quality. These solvents are particularly effective for complex paint formulations. When performing high-quality design works of art using oil paints, use special thinners. Diluent number 1 - refined oil, a colorless, liquid bystroisparyaemaya. Adding to the colors in large doses can cause them to be blurred. Diluent number 2 - a mixture of equal parts of turpentine turpentine and thinner № 1. Diluent number 3 - turpentine turpentine. All of these thinners must be taken only in small proportions to the paint, as artistic oil paints themselves are erased in the oil and solvents almost do not need. There are also various mixtures of paint thinners and oil, the so-called tees and doubles. Their use is often yellowing, pozhuhanie and darkening colors. The less use different thinners and solvents, the more safeguards to avoid spoiling the work. The best diluent is currently considered to be thinner № 2.
No comments:
Post a Comment