Fillers for paints and varnishes. paints and varnishes

When repairing an apartment, you can not do without paintwork materials: they are indispensable for decorating walls, ceilings and other surfaces. Paints have a number of advantages over others finishing materials especially the variety of colors.

In addition to decorative, paints also perform protective function: they will protect natural materials from waterlogging, drying and biodegradation (bugs), concrete from shedding, metal from corrosion. Some types of paints are able to provide fire protection and prevent the formation of mold.

Paintwork materials it is customary to call natural, artificial or synthetic compounds applied in liquid form with a thin layer (from 60-600 microns) on a painted or varnished surface. The resulting dense solid films, firmly bonded to the surface, must have sufficient strength, high durability, both in terms of long-term preservation of physical and mechanical properties and decorative qualities. Paintwork materials must be harmless to the product to be painted and living organisms.

For many years, the most important starting materials for paint compositions were natural drying oils, in the manufacture of which vegetable oils were used, which are food raw materials. To obtain the same varnishes, mainly natural resins were used, of which many were imported from African countries. Gradually, these natural products began to be replaced by synthetic polymers and, in some cases, the quality of paints and varnishes was improved.

Paints and varnishes are conditionally divided into paints, varnishes and auxiliary materials. Paints designed to create an opaque colored decorative and protective coating, and varnishes- for a transparent coating and final decorative finish of the painted surface; they also do not change the texture of the painted material.

Auxiliary materials(putties, primers, putties) are used to prepare the surface for painting and to bring varnishes and paints to a working consistency. These include emulsion thinners, drying oils and solvents, as well as driers and flushing materials.

The components of paint and varnish compositions are divided into pigments, fillers and binders.

Pigments and fillers

Pigments and fillers are designed to give paint compositions color, opacity, improve mechanical properties and durability in operation.

Pigments called colored finely ground mineral or organic matter, insoluble or slightly soluble in water and organic solvents; metal powders (powders) are also used as pigments. Pigments are natural and artificial, mineral and organic. Each pigment has its own color and has certain properties.

To the number common properties pigments include covering and coloring ability, fineness of grinding, light and fire resistance, resistance to chemical influences, weather resistance.

covering power pigment is characterized by its consumption per 1 m2 of the painted surface.

Coloring ability- this is the property of a pigment to transmit its color when mixed with white, black and blue pigments.

Fineness of grinding pigment has a strong influence on both covering and coloring power. With an increase in the fineness of grinding, the covering and coloring abilities increase.

Lightfastness The ability of a pigment to retain its color when exposed to light. This property is very important for exterior painting of buildings and structures.

Chemical resistance- the property of some pigments to retain their color under the action of alkalis and other reagents.

weather resistance- the ability of pigments to resist the combined action of temperature, moisture, carbon dioxide and other agents external environment.

Flame retardant pigments- ability to withstand actions high temperatures without destruction and discoloration. Organic pigments lack fire resistance; mineral pigments react differently to temperature changes.

Anti-corrosion ability- the ability, in combination with binders, to protect metals from corrosion. For example, red lead and white lead have anti-corrosion properties, while soot, on the contrary, contributes to the development of corrosion.

Mineral natural pigments obtained by enrichment and grinding at special facilities natural materials(ores, clays). They are used for the preparation of lime and adhesive paints, putties and colored mortars. This group of pigments includes: natural white ground chalk, dry yellow ocher (clay with a content of more than 15% iron oxide), iron minium (Fe 0, FeO) brown-red, with high light and corrosion resistance, natural mummy dry (bauxite, light and dark), having a light brown-red color, gray graphite; glauconite green and manganese peroxide.

artificial mineral pigments obtained by chemical processing of mineral raw materials. These pigments are:

1) white titanium dioxide ТiO, extracted from titanium ores;

2) zinc white, obtained by sublimation of metallic zinc, followed by oxidation of zinc vapor; they have good hiding power, light fastness, are not poisonous;

3) white lithopone, which is a mixture of zinc sulfide and barium sulfate; it is not sufficiently resistant to the action of the atmosphere, this pigment is used mainly for internal works;

4) crown zinc paint dry light yellow (lemon) color, which is a double compound of zinc chromite oxide with potassium chromate or sodium; this pigment is used in oil, adhesive and ground paints for metal;

5) red lead is obtained by calcining lead litharge at a temperature of 450 ° C; it is resistant to alkalis, but soluble in acids, well protects steel from corrosion; this pigment is used oil paints, anticorrosive primers for metal and wood;

6) ultramarine of blue color, which has an average light and alkali resistance; it is used in oil paint compositions, in color solutions and lime paints;

7) green chromium oxide Cr 0 is resistant to acids, alkalis, light and high temperatures; it is used in many paints;

8) gas soot - a product of combustion of gases (acetylene); is the lightest pigment, has a high covering and coloring power, resistant to acids and alkalis.

metal powders used along with mineral artificial pigments: it is aluminum powder - a fine powder of metallic aluminum - for external painting of metal structures and for decorative painting; golden powder - bronze powder - for decorative painting on metal, and other pigments.

organic pigments are synthetic dyes organic origin with high tinting power and color purity. They are insoluble or slightly soluble in water and other solvents. Among the organic pigments used in paints are yellow light-resistant lemon-colored pigment, strong orange, red, scarlet, ruby ​​lacquer, light blue phthalocyanite pigment, green phthalocyanite pigment, etc.

Organic pigments are used to give tone to colorful compositions on different bonds than others. However, their alkali resistance is relatively low, and light resistance is somewhat lower.

Fillers called insoluble minerals, in most cases having White color and added to paints and varnishes to save pigments and to give these materials special properties, for example, increased strength, acid resistance, fire resistance, etc. As fillers for the preparation of solutions and leveling compounds, kaolin, ground talc, sand, powdered quartz, andesite, diabase, asbestos dust, fiber and other materials.

Binders

Binders are designed to create the base and film formation of paint and varnish coatings. The following are used as binders in paint compositions: polymers - in polymer paints, varnishes, enamels; rubbers - in rubber paints; cellulose derivatives - in nitro-varnishes; drying oils - in oil paints; animal and casein glues - in glue paints; inorganic binders - in cement, lime and silicate paints. The binder is the main component of the paint composition, it determines the consistency of the paint, strength, hardness, weather resistance and durability of the coating.

Binder materials are selected taking into account the adhesive properties with the base after curing. The protective properties and durability of a paint coating to concrete, metal or other material depend not only on the type of binder, but also on the pigment, for example, aluminum pigment slows down the corrosion of steel, while soot accelerates it.

Polymer binders used in paint compositions and varnishes as an independent binder together with a solvent, and in compositions, for example, in combination with cement in polymer-cement paint compositions. The use of synthetic polymers not only significantly reduces the consumption of vegetable oils for the production of paint compositions, but also expands the range of production of new types of durable and economical paint compositions. The use of polymer varnishes and enamels made it possible to almost completely abandon imported expensive natural resins.

Widely used as polymer binders synthetic resins and rubbers and cellulose derivatives, soluble to the required consistency in organic solvents. The formation of a paint film in this case occurs due to the evaporation of the solvent.

Drying oils are called binders obtained from drying oils or some artificial products, which, after hardening in thin layers, form strong and elastic coating films. Film-forming compositions that do not contain drying oils, but are able to replace them in painting works, are called artificial or synthetic drying oils. Drying oils are used to dilute paints, make primers, fillers, to cover wood, plaster and other surfaces. Drying oils must dry in thin layers, without giving a cast in 24 hours at a temperature of 20 ° C. To speed up drying, a desiccant is introduced into drying oils.

Drying oil natural(oil) produce two types: oxidized and polymerization. Oxidized drying oil is obtained by treating linseed or hemp oil by blowing air while heating to 160 ° C with the introduction of a manganese or manganese-lead-cobalt desiccant. Polymerized drying oil is obtained by polymerization of linseed oil by heating at a temperature of 275 ° C with the introduction of a manganese-lead-cobalt desiccant. Since expensive vegetable oils are used for the preparation of natural drying oils, its use in construction for outdoor and interior decoration metal, wood and plaster is limited.

Drying oil semi-natural are made from polymerized, oxidized and other compacted oils treated at a temperature of 150–300 ° C in the presence of a desiccant and dissolved in volatile solvents (white spirit, turpentine, benzene, etc.). Semi-natural drying oils include drying oil oxol and oxol-mixture. Drying oil oksol is a substitute for natural drying oil, made by compacting linseed oil by blowing air in the presence of a desiccant, followed by the addition of a solvent (white spirit or solvent naphtha). Drying oil oksol is used to dilute thickly grated paints for interior and exterior use. Drying oil oxol-mixture - a substitute for natural drying oil, made by sealing a mixture of linseed or hemp oil (or mixtures thereof) with sunflower oil by blowing air in the presence of a desiccant, followed by the addition of a solvent (white spirit, solvent naphtha). Oxol-mixture drying oil is used to dilute thickly grated paints used for interior finishing work.

Drying oils synthetic , unlike natural ones, do not contain vegetable oils or contain no more than 35% of them. Of the many artificial drying oils, glyphthalic, slate, synthol and coumaronoindene, as well as ethinol (lacquer), are widely used. Glyphthalic drying oil is obtained by the interaction of vegetable oils, glycerin and phthalic anhydride with the addition of a desiccant, followed by dilution with special gasoline (solvent for the paint and varnish industry) to a paint consistency. This drying oil is used for the manufacture of high-quality paint compositions for exterior and interior decoration of metal, wood and plaster. Shale drying oil is a solution of diesel and generator shale oil in organic solvents; it is used for the manufacture of colorful compositions for interior decoration. Etinol - waste from the production of chlorophene rubber; it is used for anti-corrosion primers and paints. Coumaronoindene drying oil is a solution of coumaronoindene resin in organic solvents; use it only for the manufacture of putties and primers for interior work.

Adhesives used as a binder in water-adhesive paint compositions, for adhesive primers and putties, as well as a stabilizer in the manufacture of water-based paint emulsions. Distinguish adhesives animals (mezdrovy, bone, casein), vegetable (dextrin) and artificial. Mezdrovy glue, bone glue, casein and dextrin are of limited use in construction, they are being replaced by more effective artificial glues. artificial glue is a solution of artificial resins in water, it comes in the form of a mixture of carboxymethylcellulose and methylcellulose. Carboxyl methyl cellulose is a product of chemical processing of yellowish wood pulp, which is little susceptible to decay, is able to swell and dissolve in water. Carboxylmethylcellulose is used in adhesive and oil paints. Methylcellulose has a high resistance to acids and alkalis, which is what distinguishes it from carboxymethylcellulose. Polymer adhesive is a mixture of polymer synthetic substances with high adhesive power. To obtain it, a polyvinyl acetate resin is used. The resulting binder is used in the form of emulsions for gluing film materials and washable wallpapers, aqueous or alcoholic solutions of polyvinyl acetate.

Thinners are intended for thinning thickly grated or diluting dry mineral paints. Unlike solvents, thinners contain a film former in the amount necessary to obtain a high-quality paintwork. Emulsion thinners are water-in-oil emulsions. They are used to obtain primers and dilute thick oil paints, which makes it possible to more economically use low-polymerized drying oils and synthetic resins. Emulsion thinners are used to dilute zinc and lithoponic white, some colored thick paints, as well as iron minium, mummy and ocher. The amount of thinner for various paints should not be more than 22–40%; if at the same time the paint consistency of the paint composition did not work out, then a solvent is added to the paint. The disadvantages of emulsion thinners include the low quality of coatings, so their use is limited.

Solvents are liquids used to bring paint compositions to a working consistency. Depending on the purpose, solvents are divided into three types: for oil varnishes and paints; for glyphthalic, pentaphthalic and bituminous varnishes and paints; for nitrocellulose, epoxy and perchlorovinyl varnishes and paints. Solvent for adhesive water-based paints is water. Turpentine, coal solvent, white spirit and other solvents are used as solvents.

colorful compositions

Paint compositions include oil and enamel paints, varnishes, water-based and volatile resin paints.

Oil paints are a mixture of pigments and fillers ground in paint graters with drying oil from vegetable oils. Oil paints are produced in the form of thickly grated paints, which must be diluted with drying oil to a painting consistency before use, and ready-to-use paints.

Thickened colorful compositions contain 12–25% drying oil, and paints ready to use, – 30–50% of the mass of the pigment. Oil paints are used for exterior and internal coloring for metal, wood, plaster and concrete. Complete drying for oil paints at a temperature of 18–23 ° C should be no more than 24 hours, the drying time for black oil paint is about 30 hours. The following main types of oil paints are used in construction: for outdoor painting- zinc white, lead greens and zinc, black paint, earthen thick paints (mummy, ocher), iron minium, etc .; for interior painting- zinc and lithopon white, thick zinc greens, artificial light and dark red cinnabar, iron minium and other colored oil paints. Oil paints on drying oils from vegetable oils should be used on dried plaster and hardened concrete.

Enamel paints are suspensions of mineral or organic pigments with synthetic or oil varnishes. Among enamel paints, the most common are alkyd, epoxy and urea-formaldehyde. Enamel paints have good light resistance, anti-corrosion, dry quickly. They are used for painting on metal, wood, concrete and plaster of internal and external surfaces.

Alkyd paints- these are suspensions of finely dispersed pigments in glyphthalic, pentaphthalic and other alkyd varnishes with the addition of solvents and a desiccant. Alkyd paints include glyphthalic enamels of general consumption, with reduced and increased water resistance, but unstable to the action of alkalis, and pentaphthalic enamels of various brands, which have greater durability and water resistance than glyphthalic ones. To the group alkyd paints styrene alkyd enamels are also included, which have increased chemical resistance and water resistance, high hardness and gloss.

Enamel epoxy paints are a suspension of pigments in solutions epoxy resin. They have increased chemical resistance and water resistance, they are used as anti-corrosion coatings for metal and wood.

Suspension of pigment urea-formaldehyde resins forms carbamide enamel paints of increased water resistance; they are used to cover built-in equipment.

Lucky are solutions of resins in volatile solvents. The latter evaporates when varnishing the surface of products, and the resin in the form of a thin film remains, giving the surface shine and hardness. Lucky is divided into five groups.

Oil-resin varnishes– solutions in organic natural solvents – alkyd or synthetic resins modified with drying oils. They are used for interior and exterior coatings on wood and light-colored oil paints, for diluting enamels and varnishes, obtaining resistant anti-corrosion coatings and preparing fillers and primers.

Oil-free synthetic varnishes- solutions of synthetic resins in organic solvents. Varnishes based on urea-formaldehyde resins are widely used in construction, used to coat parquet and plank floors, as well as floors made of particle boards. Perchlorovinyl varnishes of indenchloride and perchlorovinyl are used for varnishing oil coatings in order to improve their anticorrosive properties.

Varnishes based on bitumen and asphalt– solutions of bitumen, asphalts and vegetable oils in organic solvents (gasoline or benzene). Black or brown bituminous varnishes are resistant to acids and alkalis. Bituminous and asphalt varnishes are used for anticorrosive vapor and waterproofing coatings, furnace finishing, painting gas stoves and other surfaces.

Alcohol varnishes and varnishes- solutions of natural and artificial resins in alcohol. They are made in various colors (yellow, green, blue, brown, etc.) and are used for polishing wooden surfaces and coating glass and metal products.

Nitrocellulose and ethylcellulose varnishes– solutions of cellulose ether resins in organic solvents. To improve the quality of the varnish, plasticizers are added to the latter - natural, artificial or synthetic resins. Nitrocellulose lacquer comes in yellow and brown; it is used for varnishing wooden products and furniture. Ethylcellulose varnish is colorless; use it for varnishing painted and unpainted wood products.

Waterborne and volatile resin compositions There are mineral-based, polymer-cement, emulsion (latex) and volatile resin paints and enamels. Mineral-based paint compositions are a mixture of alkali- and light-resistant pigments and an inorganic binder with various additives, diluted with water to the state of a paint consistency. By type of binder, mineral-based paints are lime, silicate and cement.

lime paints consist of lime, pigment, sodium chloride or calcium chloride, as well as calcium stearate or calcium salts, acids, linseed oil. Lime paints are used for painting facades and interior spaces on brick, concrete and plastered surfaces.

silicate paints are made from a mixture of finely ground chalk, talc, zinc white and alkali-resistant pigment, followed by mixing solutions of sodium or potassium soluble glass. Factory-made silicate paints are produced in two types of two-pack packaging: for facade and interior decoration. Facade paints, consisting of pigment, fillers and potash liquid glass, are used for painting facades, as well as for interiors with normal and high humidity; interior paints, consisting of pigments and fillers, are used for painting interiors on concrete, plaster and resin-free fiber boards.

Silicate paints are much more economical and durable than perchlorovinyl, lime and casein paints. To protect metal from corrosion in atmospheric conditions, in a humid environment, in moderate saline solutions, for finishing embedded parts in large-panel housing construction, protective silicate paints are used, which are a suspension of zinc dust and pigments in a silicate-silicone copolymer.

cement paints are used for exterior and interior painting of rooms with high humidity, as well as for painting cellular concrete and embossed finishes.

Polymeric paints are made on the basis of cement, alkali- and light-resistant pigments with the addition of synthetic resins. Polymer cement paints are produced in various colors for summer and winter work. Polymer-cement paints for summer jobs produced in a two-pack, when used, mixed with an aqueous dispersion of the polymer; they are used for exterior and interior decoration of buildings, as well as for painting panels of various surfaces. Polymer-cement paints for winter work are used for exterior decoration of facades and building structures.

Emulsion (latex) paints are pigmented emulsions or dispersions of a polymer in water. From emulsion paints in construction are used water emulsion acrylic paints , which are a suspension of pigments and fillers in acrylic latex; Titanium dioxide is included as the main covering pigment in acrylic emulsion paints. These paints can be different in color and tone, non-toxic, fire and explosion-proof, have high light and weather resistance, and can be used in rooms with high solar radiation.

Volatile paints are a suspension of pigments in varnishes (volatile resin compositions). Drying of such coatings occurs as a result of volatilization of the solvent. At in large numbers binder in paint coatings are obtained with a gloss and have a good filling. These colors are called enamels. They have not yet received wide application in construction; the most common of them are perchlorovinyl, vinyl chloride volatile resin enamels, etc. Perchlorvinyl enamels are a solution of dry perchlorovinyl resin mixed with volatile organic solvents with the addition of pigments, plasticizers and other resins, such as alkyd. They are characterized by increased water and chemical resistance, so they are used to protect various building structures and parts from the effects of chemically aggressive environments. They are produced in various brands and colors, brought to a paint consistency with coal-tar solvent or special solvents, they dry at 18–23 ° C for 2–4 hours.

Vinyl chloride enamels and paints produced in various colors. They are distinguished by increased oil resistance, they are used for the same purposes as perchlorovinyl.

Ethercellulose enamels used in construction are divided into nitroglyphthalic, nitrocellulose and ethylcellulose. Nitroglyphthalic enamels are a solution of nitrocellulose and glyphthalic resin in organic solvents with the addition of plasticizers and pigments, and nitrocellulose and ethylcellulose enamels are a suspension of pigments in nitro- or ethylcellulose varnishes; they have increased toxicity, fire and water resistance. They are used for painting metal and wooden structures indoors. Ethylcellulose enamels are less flammable than nitroglyphthalic and nitrocellulose enamels; they are prepared in a less toxic solvent. Ethylcellulose enamels are used for factory painting of kitchen furniture and built-in equipment.

Auxiliary materials

As auxiliary materials at painting works apply putties, putties, primers, as well as solvents and thinners.

Putties called finishing compositions used to level surfaces to be painted. Putties come in various compositions depending on the type of paint used. Under water-borne paints, vitriol, or alum, adhesive and polyvinyl acetate putties are used. Vitriol, or alum, putty consists of drying oil oxol, animal glue, oil, laundry soap, copper or zinc sulfate and water. It is used for adhesive or silicate painting, it is applied with a brush or spray. Part adhesive putty includes 15% aqueous solution of animal glue and 75% chalk; it is applied with a spatula.

Putties perchlorovinyl and polystyrene are paste-like masses applied to the surface intended for painting made of wood, concrete, plaster and metal. Perchlorvinyl putties are waterproof, dry quickly (no more than 2 hours); some brands of them are suitable for operation at temperatures below 0 °C. Polystyrene putties are used for the same purposes as perchlorovinyl, but they are less durable.

putties are paste-like compositions used for coating window frames with glazing, seam joints and roof ridges made of sheet steel. Used for window coverings chalk, bleach and naphthenic putties, consisting of natural drying oil, ground chalk and red lead. When constructing a roof made of sheet steel, a special roofing putty is used, consisting of natural drying oil, chalk and iron minium, or putty on Kuzbass varnish, iron minium and ground chalk. Putties have good water resistance and plasticity.

Primers - These are colorful compositions consisting of pigments or dyes, fillers and binders. They are produced in two types: primers for water-based paints and primers for oil and synthetic paints. For waterborne paints apply vitriol primer, soap-adhesive, lime with alum, etc.; they are used for lime or silicate coloring. Primers for oil painting usually diluted with drying oil or solvent. AT finishing works primers are used to reduce the porosity of the painted surface, to reduce the consumption of expensive paint compositions and improve appearance of the resulting coating, to enhance the protection of metal surfaces from corrosion, for pre-painting wooden and other surfaces intended for varnishing, as well as to enhance the adhesion of the paint layer to the base.

Pigments. The quality of pigments is characterized by a complex of technological and operational properties arising from the requirements for them.

Technological properties

The coloring ability (intensity) of a pigment is the ability to transfer its color when mixed with a white pigment. The greater the coloring power, the less pigment is required to obtain the color of the desired tone, and it can be partially replaced by a filler.

The hiding power is estimated by the consumption of pigment (g) per 1 m2 of the surface to be painted, necessary to cover the contrasting color (for example, black and white stripes) of this surface.

Hiding power and coloring power are not always related to each other. So, a high-intensity blue pigment - azure - has a low hiding power, and a highly opaque red pigment - minium lead - is characterized by a low coloring power.

The dispersion (fineness of grinding) of the pigment significantly affects both its coloring ability and hiding power. The smaller the pigment particles, the higher these figures. Coarsely dispersed pigments give a rough surface and provoke the rapid destruction of the coating. Natural pigments, obtained by grinding rocks, consist of particles with a size of 0.5 ... 40 microns; in artificial ones, the dispersion is higher - 0.1 ... 2 microns.

The oil absorption of a pigment is characterized by the amount (in ) binder (linseed oil), necessary for the formation of a pigment paste by grinding it with drying oil. The less drying oil the pigment requires, the cheaper the paint and the more resistant the coating will be, since the binder film degrades first in the paint layer. The oil absorption depends on the dispersion of the particles, their shape and wettability.

Surfactant additives are used to maintain a high dispersion of the pigment and prevent its aggregation in paintwork materials.

Operational properties

Light fastness is the ability of pigments to retain their color when exposed to light. sunlight(mainly the UV component). Some pigments (mostly organic) fade in the light.

Weather resistance - a complex property - the ability of pigments to withstand the effects of the external environment without destruction and color change: oxygen, CO2 and other gases contained in the air, water, freezing and thawing. This property is the most important for facade paint pigments.

Chemical resistance - the ability of pigments to resist the action of acids and alkalis. In particular, alkali resistance is absolutely essential for pigments in paints applied to concrete and plaster walls, and for pigments used in lime and silicate paints.

Heat resistance - the ability of a pigment to withstand high temperatures without changing color and decomposition. The heat resistance of pigments should be taken into account when painting heating systems and thermal installations.

Harmlessness of pigments. This problem is due to the fact that some pigments contain toxic substances: compounds of lead, chromium and others heavy metals; this must be taken into account when painting interiors.

The special properties of the pigments are needed when the paintwork performs special functions. So, if the main task of painting is corrosion protection, which is important for metal structures, it is desirable that the pigment has passivating properties (aluminum powder, red lead). Another example is the electrical conductivity of the pigment, which is necessary in cases where the coating should not accumulate static electricity.

There are pigments that change color when the temperature changes. certain limits. Paints with such pigments can serve as temperature indicators.

The main types pigments

Pigments are usually divided into the following features: - by chemical composition: inorganic and organic; – by origin: natural and synthetic; - by color: achromatic (black and white) and chromatic (color).

Natural mineral pigments (the old name is "earth pigments" or "earths") - known since ancient times, but still a type of pigments widely used in construction. They are obtained by mechanical enrichment, grinding or elutriation of colored rocks (mainly clays). These pigments have a muted color, but their light and weather resistance is very high.

The predominant gamut of shades of natural pigments is yellow-red-brown, caused by the presence of iron oxides of various compositions in the composition of clays. These pigments include: ocher ( yellow), iron minium (brick red), mummy (brownish red), umber (brown, red-brown after calcination), sienna (dark yellow, chestnut after calcination).

Black natural pigments - manganese peroxide (Mn02) - manganese ore pyrolusite and graphite - a modification of pure carbon - give a beautiful range of tones from silver gray to black; exceptionally thermo-, chemical- and weather-resistant pigment.

White natural pigment - chalk (CaCO3) - is used to a limited extent (mainly in water-based paints) and as a filler in putties; hiding power is low, since n = 1.6.

Artificial inorganic pigments are obtained by chemical processing of mineral raw materials. They have a brighter and more varied color and greater color stability compared to natural pigments; however, in some cases, their durability (light and weather resistance) is lower than that of natural ones.

white pigments. Titanium white (Ti02) - rutile titanium dioxide - the most common high-quality white pigment at present (l = 2.72; hiding power - 15 ... 25 g / m); light and weather resistant; applicable to all types of paints.

White zinc (ZnO) - high light fastness; weather resistance - average; u \u003d 2.02, hiding power - 100 ... 120 g / m2; well combined with other pigments, not resistant to acidic and alkaline environments (i.e. not recommended for paints on mineral binders).

Lithopone white (mixture of ZnS and BaSO4) (colouring power - medium (l = 1.8 ... 2.0; hiding power - 120 ... 140 g / m)) - pigment, has low weather resistance, turns yellow from UV radiation and is recommended only for internal work; used in primers.

Yellow and red pigments. Like natural pigments, this range is dominated by pigments based on iron oxides: yellow iron oxide, red iron oxide (redoxside) and mars (a group of pigments of various shades). They are characterized by high hiding power, weather and light resistance.

Lead and zinc pigments have a brighter and more saturated color: lead crown (lemon, yellow and orange), zinc crown (lemon and yellow) and red lead (orange-red). These pigments (except red lead) are less resistant than iron oxide, and are poisonous (especially lead).

Blue and green pigments. To the blue pigments that received wide use, includes iron blue and ultramarine.

Iron blue (milori) - iron and potassium ferrocyanide - an intense blue pigment, used in a mixture with white and yellow (to obtain green) pigments; not alkali resistant.

Ultramarine - sodium aluminosilicate containing sulfur; alkali-che- and light-resistant; in acidic environments it becomes discolored (in everyday life it is used to blue linen).

Cobalt blue is a very high quality pigment; due to the high cost, it is rarely used, mainly as a paint for ceramics.

Among the green pigments, one of the best is chromium oxide (Cr2O3), olive-green in color, which has high light and weather resistance, due to its high hiding power, it is usually used in a mixture with fillers; used for the preparation of all types of paints and enamels; chromium oxide is especially often used in oil paints for roofs.

Copperhead (basic acetic acid copper) - an intensely colored green pigment; It is usually used in a mixture with titanium white to obtain light green paints. Mixing with pigments containing zinc or sulfur salts (for example, with zinc white and litopone) is unacceptable. The light fastness of verdigris is lower than that of chromium oxide.

Green pigments can be obtained by mixing blue pigments with yellow ones; for example, zinc green - a mixture of zinc crown with azure, is mainly used in paints for wooden surfaces due to low alkali resistance, it is not recommended for painting concrete and plastered surfaces and is completely unsuitable for lime and silicate paints.

Black pigments. Among the black pigments, the most important are carbon blacks obtained using various technologies. For paints, carbon black is used, which has minimal amount impurities. Highly dispersed soot forms colloidal solutions with the binder. Soot is absolutely light and chemical resistant. In addition to soot, especially for colored plasters, an alkali-resistant iron black pigment (nitrous oxide - iron oxide - FeO Fe203) is used.

Metal pigments are fine metal powders (aluminum, bronze powder) with a protective coating; used for protective coatings of metal structures and as a second pigment in metallic paints. Not suitable for water based paints.

Organic pigments are, as a rule, organic dyes converted into an insoluble form. They differ from inorganic ones in greater color intensity, variety and purity of tones, but less light, weather and chemical resistance. The most widespread are azo pigments, phthalocyanine and polycyclic pigments.

Azopigments have a continuous range of colors from greenish-yellow to burgundy. They are alkali resistant.

Phthalocyanine pigments have blue, cyan and green colors. It is one of the most resistant to UV radiation, heat and chemical attack a group of organic pigments used for construction purposes for over 50 years.

Polycyclic pigments are a promising type of pigments with a wide range of color scheme, high coloring power and satisfactory light and heat resistance.

Fillers. Fillers, like pigments, are mineral powders that are insoluble in the binder. Unlike pigments, they have a low refractive index (n = 1.45 ... 1.65), close to the refractive index of drying oils and varnishes. Because of this, the fillers visually disappear in the binder film and, as a result, have a very low hiding power. In other media with a lower refractive index, fillers can play the role of pigments (for example, chalk in glue paints).

Fillers are cheaper and more readily available than pigments. They are used to save expensive pigments, as well as to improve the painting, technical and operational properties of coatings. In large quantities they are used in putties.

Depending on the method of preparation, fillers are distinguished: - natural-dispersed: kaolin, chalk, bentonite, diatomite; – mechanically dispersed: chrysotile silty asbestos, barite, talc, mica, muscovite, gypsum; - synthetic: aerosil; white soot; blanfix - synthetic barite; aluminum oxide and hydroxide, etc.

Fillers in paints and varnishes not only replace some of the pigments, but also perform special functions. Thus, finely dispersed fillers prone to the formation of coagulation structures (for example, bentonite, aerosil) "thicken" the paint, preventing the sedimentation of pigments and providing the necessary rheological properties. Fillers with low oil absorption (barite, mica) "thinn" the paint.

Fillers of fibrous (asbestos) or lamellar (mica) form reinforce the paint film and reduce the likelihood of coating cracking.

Combined application of pigments and fillers with particles different shapes and size allows you to get a denser package, which reduces the consumption of the binder (a similar idea is used in concrete when selecting aggregates according to the grain composition) and, as a result, increases the weather resistance and hardness of the film. So, in paints on titanium white (TiO2), the weather resistance of the coating increases sharply with the introduction of 25 mica or 35 ... 50% talc (from the weight of Ti02).

Fillers with high oil absorption (aerosil, kaolin, chalk, etc.) reduce the gloss of enamels, making the surface matte. With the help of the selection of fillers, other problems can also be solved.

Fillers are inorganic compounds with a lower refractive index than pigments (according to DIN 55943, 55945, the refractive index for fillers is less than 1.7). The list of standard pigments and fillers of various crystalline forms and the values ​​of their refractive indices are given in Table. 15. Most fillers are natural minerals: calcite, chalk, dolomite, kaolin, talc, mica, diatomaceous earth, barite, quartz. But some of them are obtained by precipitation reaction (calcium carbonate or barium sulfate, pyrogenic silicon dioxide). The density of conventional fillers is 2.5-2.8, barite - 4 g/cm3.

The most commonly used filler is calcium carbonate. AT Western Europe calcium carbonate in the form of crystalline calcite and amorphous chalk makes up 80-90% of all fillers used. In the formulations of many coatings, only calcite is used as a filler. However, up to six types of different fillers can be used in matte paint formulations, differing in particle size, crystal form and activity.

As a rule, fillers are used to reduce the cost of materials, but sometimes they can also be used to modify the properties of paints. When using fillers, it is possible to achieve values ​​of CVD > CVF, at which the air-filled pores ensure the hiding power of the dried film, thus saving expensive titanium dioxide.

Table 15

Fillers increase the hardness of coatings, hiding power and specific gravity paint, reduce its cost. In addition, the type of filler affects the weather resistance, abrasion resistance, gloss of coatings, their resistance to soiling and gas permeability, as well as the rheological properties of paints.

The main properties of fillers are particle size, brightness and whiteness. The finer the particles, the lighter the filler, but the higher its absorbency, characterized by oil absorption. The crystalline form of the filler significantly affects its ability to disperse and rheological activity in liquid coatings and the physical and mechanical properties of coatings.

Unlike lamellar (kaolin, talc and mica) or fibrous fillers (wolastonite), fillers of a cubic or rhombohedral structure (calcite or dolomite) are easier to disperse and have lower oil absorption. Lamellar and fibrous fillers improve the physical and mechanical properties of coatings and prevent the formation of cracks, acting as reinforcing agents.

The hardness and particle size of the filler affect its abrasive ability, determined by the Einlechner method. To do this, the filler paste is mixed in special apparatus with a metal sieve for 1 hour. Then evaluate the abrasion of the metal sieve. Abrasiveness is determined by the ratio of the specific surface area of ​​the metal sieve before and after the test. It should be noted that high abrasiveness is a disadvantage of the filler, as it causes damage to the dispersing equipment when production of coatings and sprayers - when applying materials by pneumatic spraying.

Paints and varnishes are those materials that, when applied to a prepared surface, are able to form a strong protective film after drying.

Paints and varnishes are used in construction when carrying out finishing decorative work indoors and in protecting various building structures from corrosion and precipitation.

Coatings are compounds that are applied to prepared substrates and surfaces to be finished in thin layers in liquid form using brushes, rollers and spray methods. After drying, the compositions of paintwork materials are able to form a protective film, which is distinguished by the ability to protect the surface from corrosion, from atmospheric precipitation, and also gives the treated surfaces a beautiful and attractive appearance. Depending on the thickness of the used coating material, the protective film can have between 60 and 500 microns after drying. The main ones include various paints capable of forming a coating of the desired color.

Also include varnishes of various origins that are capable of forming a protective, transparent and durable film after drying. Also, pigments and binders, various auxiliary substances such as paint and varnish thinners, solvents, desiccants, primers, putties and other materials are referred to paintwork materials. The paint and varnish industry produces for construction needs, mainly ready-to-use various varnishes and paints, enamels or thickly ground paints, which consist of pigments and fillers, as well as binders (glue, drying oil, polymers). Coating materials are packaged in convenient packages and are produced in a large assortment of different colors and shades.

Thickly ground paints are colored pastes that are diluted to the desired consistency with natural drying oil before use, or semi-natural drying oil can be used. To reduce the viscosity of various paints, turpentine or white spirit is also used in an amount of up to three percent. If the paint composition contains a solvent in an amount of more than three percent, the gloss of the coating decreases, cracks appear and the quality of the protective coating of the film deteriorates after drying.

Paintwork materials and their properties

The properties of paints and varnishes are divided into chemical, physico-chemical and painting and technical. chemical properties Paint and varnish materials usually refer to the percentage of constituents, solvents, film-forming substances, water-soluble salts, fillers, and so on. physical and chemical properties primarily include viscosity, density, hiding power, film drying (hardening) speed. Painting and technical properties include density, grinding degree, flowability, applicability, overflow, and others. In other words, this includes all properties that characterize the convenience in working with paintwork materials .

One of the most important properties of paints and varnishes is coverage. Coverage of paintwork materials is the ability of a material to uniform distribution on the basis of a single-color surface, make the previously applied layer invisible. The dispersion and fineness of grinding pigments of paint and varnish compositions has great importance since the finer the pigment is ground, the better the surface is painted, the hiding power and the coloring power of the material become better.

Properties of paint coatings:

The paintwork is formed on the surface of the material as a result of applying paintwork materials and drying. As a result of drying paintwork materials, a protective film is formed.The protective film, in turn, has different properties and answers different requirements, which are listed below.

2. Chemical properties (resistance when exposed to high temperatures, gases, atmospheric precipitation, steam, various aggressive chemical solutions, alkalis, oils, oil, gasoline, soap solutions, etc.).

3. Physical and chemical properties (hardness, wear resistance, elasticity, strength, bending strength, adhesion).

4. Protective properties (frost resistance, vapor permeability, water resistance, corrosion resistance, heat resistance, light resistance, resistance to various atmospheric conditions.

5. Painting and technical properties (should be amenable to grinding, polishing and other types of surface treatment. Stripping, for example.

6. Electrical insulating properties.

7. Special properties. Certain types of coatings have special properties inherent only to them.

Another important property is oil absorption, which is expressed in the amount of oil needed to add 100 g of pigment to obtain a homogeneous paste. The lower the oil absorption of pigments, the better the painted compositions are obtained, because the protective paint is destroyed due to aging of the film and not the pigment. durability is an important property of paint compositions to form, after drying, a resistant and durable protective film that can reliably protect metal coatings from corrosion.

Zinc and lead crowns, white lead, aluminum powder, minium lead and other compounds have high anti-corrosion properties. The vapor permeability of paint and varnish compositions depends directly on the anti-corrosion properties of paint and varnish coatings.

The composition of paints and varnishes (LKM)

The composition of paints and varnishes includes pigments, film-forming agents, various fillers and plasticizers, as well as solvents, additives and desiccants. Film-forming paintwork materials are a multicomponent system and, after being applied to the treated surface, a protective film is formed as a result of various physical and chemical processes.

Film-forming agents are introduced into the composition of paintwork materials in order to bind fillers with pigments, to dissolve paintwork materials with organic solvents, to form a strong protective film after drying, and also to ensure good adhesion to the treated surface. Various polymerization resins (based on vinyl chloride, methacrylates, acrylates), natural resins such as bitumen, rosin, asphalt and others, polycondensation resins (polyurethane, alkyd, formaldehyde, epoxy, organosilicon and others. Cellulose ethers, fatty acids, tall oil and vegetable oils also belong to film-forming substances.

Alkyd resins occupy the first place among film-forming substances in the production of paint and varnish materials. Alkyd resins are polyesters with a branched structure. These are products from the incomplete processing of polybasic acids, monobasic fatty acids and alcohols. Alkyd resins are classified depending on the alcohol used in their manufacture. Thus, glyphthalic alkyd resins (based on glycerin), pentaphthalic alkyd resins (based on pentaerythritol), ethryphthalic alkyd resins (based on etriol) and xifthalic resins based on xylitol.

For good solubility of the alkyd resin, which gives the finished paint and varnish composition elasticity and water resistance, it is modified with oils plant origin or fatty acids. Therefore, alkyd resins are usually divided into drying and non-drying. The oil content in such compositions can reach 70 percent. If the composition contains up to 35 percent oil, then such compositions are called lean, if the oil content is from 46 to 55, the compositions are called medium fat. If the composition contains oils in a percentage of 55 to 70, then such compositions are called fatty. when the formula contains less than 35 percent oil (for example 34), such a composition is called ultra-lean.

Extensive experience in the use of pentaphthalic alkyd resins has shown that such resins acquire the best protective characteristics when the oil content is present in the range of 60-65 percent. And for glyptal resins, the oil content should be up to 50 percent. I will name below in order, depending on the speed of drying:

1. Tung oil.

2. Oytisic oil,

3. Linseed oil,

3.Castor oil,

5. Sunflower oil.

Oils are located in reverse order according to light resistance. These data are convenient to use, for example, for the manufacture of various alkyd paints and varnishes. For the manufacture of primers, linseed and tung oils are used, since primers are used as an intermediate layer for better adhesion of paintwork materials to the base and are not exposed to sunlight. Alkyd compounds can be used also together with other resins (polycondensation, polymerization) and cellulose nitrates. Depending on the modifying agent used, such resins are divided into alkyd-urea, alkyd-melamine, alkyd-styrene, alkyd-epoxy, alkyd-acrylic and alkyd-polyorganosiloxane. they combine the properties of an alkyd resin and a modifying component.

Alkyd resins can be divided into:

♣.Water dilutable (water soluble) and water insoluble.

♠. Dilutable with and soluble in organic solvents.

♣ Use of alkyd resins:

♦ Water-borne alkyd resins are now found wide application in the preparation of water-based paints and varnishes. Such materials have a number of advantages over others (for example, over paintwork materials based on organic solvents). They are environmentally friendly and do not harm the human body in fire-safe. In such compositions, water-borne alkyd resins interact with phenol-formaldehyde water-soluble resins, or with amino-formaldehyde resins, which are introduced into the composition as a hardener and as a result a reliable protective film is formed.

♦ Alkyd resins diluted with water are used to prepare water-based primers and enamels. Glyphthalic resins are diluted with organic solvents and are used in the production of enamels, primers and fillers for interior work. Pentaphthalic resins are widely used in the production of varnishes and enamels to protect structures in temperate climates outdoor .Along with this, various primers, enamels, varnishes, drying oils, cold and hot drying putties are made from drying alkyd resins.

♣ Pigments

Various fillers are used to give paintwork materials the necessary properties. These substances are added to the main ingredients in order to increase strength, thermal conductivity, resistance to various external factors, improve the appearance of the surface.

There are several types of fillers for paints and varnishes.

Talc

Powder similar in chemical composition to magnesium silicate. It is characterized by softness, oiliness to the touch and white color. Talc is formed by crushing talcite or talcomagnesite rock concentrate. When this element is added to the composition of paints and varnishes, their strength increases. It also improves adhesion, resistance to temperature extremes, mechanical damage and defects resulting from contact with chemicals.

Kaolin

It is a hydrated aluminum silicate, the chemical form of which is Al2O3-2SiO2-2H2O. It contains impurities such as oxides of iron, calcium, potassium and titanium. Kaolin is characterized by white color and flexible structure. Its feature is also the ability to contact with water and other liquids.

The scope of kaolin is extensive. It is necessary for obtaining oil and water-based paints, anti-corrosion matte and semi-gloss coatings, in the perfumery field, in the manufacture of porcelain, rubber and many other materials.

Barite

Barium sulfate, which is of natural origin. Usually white or gray in color. Barite is extracted from spar by grinding. When added to the composition of paints and varnishes, it gives them additional resistance to chemical attack. This quality is achieved due to the chemical inertness of the element.

Calcium carbonate

It is used in paint and varnish compositions, both natural and artificial. In the first case, it is chalk, limestone, marble, in the second case, precipitated chalk. Among the impurities contained, magnesium carbonate, iron and aluminum oxides, and silicon compounds are distinguished. Artificial calcium carbonate is supplemented with water-soluble substances. As a filler, it increases protective properties coatings (resistance to water, corrosion and mechanical stress).

Pigments

By origin, they are divided into natural and artificially obtained. For example, the production of gray and white pigment is the result of the use of carbon or aluminum powder. And for chromatographic pigments, metal oxides are used. Their main advantage is that they do not dissolve in water. Thus, paints and varnishes, the color of which is obtained with the help of pigments, are characterized by a persistent shade, as well as high anti-corrosion properties.

KRASSNAB: fillers for self-leveling floors

Specialists of the KRASSNAB company know that fillers play especially important role. Indeed, often these surfaces are subjected to mechanical action of water and chemical compositions. Despite this, the floors must last a long time and be reliable.