PROTECTIVE AND DECORATIVE MATERIALS
The creation of protective and decorative coatings on the surface of wood and wood materials in order to improve the appearance and protect against environmental influences is called product finishing. For protective and decorative coatings of wood and wood materials, paints and varnishes, films and plastics are used.
Depending on the materials used, the finish can be transparent or opaque. Artificial reproduction of the texture and color of wood or various patterns on the surface to be finished is called an imitation finish. The application of varnish to the surface of parts or products is called varnishing, and pigmented paints and varnishes- staining.
Surface preparation for finishing includes sanding and sanding. Wood surface preparation for transparent finishes includes demineralization, bleaching, surface dyeing, priming, filling, intermediate drying and sanding, for opaque finishes - demineralizing priming, filling (local), intermediate drying and sanding.
The creation of protective and decorative coatings for transparent finishing includes varnishing, intermediate drying and sanding, for opaque finishing - filling, painting, intermediate drying and sanding.
When refining paints and varnishes with a transparent finish, sanding, smoothing, polishing, glossing, matting is required, with an opaque finish - grinding, polishing, glossing.
Finishing is the final process in the manufacture of furniture, in terms of labor intensity, it makes up 40% of the entire processing cycle, and the quality and appearance products mainly depends on the materials used. According to their purpose, paints and varnishes are divided into three main groups:
materials for preparing wood surface for finishing (primers, fillers, fillers);
materials that create the main paint and varnish layer (varnishes, enamels, paints, finishing pastes);
materials for ennobling paint and varnish coatings (leveling liquids, polishing pastes and varnishes, grinding pastes, compositions for surface refreshing).
Paints and varnishes are compositions consisting of a number of initial substances - components that perform different roles in the paint and varnish material and the coating it creates. These components are classified into groups:
film-forming substances and binders - synthetic and natural resins, waxes, adhesives, drying oils, colloxylin, etc., which, as a result of physicochemical processes, form a solid film that adheres well to the material of the product;
driers - components that accelerate the drying time of coatings.
Materials for surface preparation for finishing include grinding pastes and powders, primers, fillers, fillers, putties.
Grinding Pastes
Grinding pastes are abrasive powders ground on a soft, easy-to-grind binder. For the preparation of grinding pastes, abrasive powders of tripoli, pumice, electrocorundum, silicon carbide are used.
Non-drying fats and oils, wax and paraffin, technical petroleum jelly, etc. can be used as binders. Turpentine, white spirit, kerosene, gasoline, and water are used as solvents.
Bonding materials ensure uniform distribution of the abrasive powder in the paste, keep the abrasive on the surface to be ground, and remove the heat generated during grinding.
Depending on the ratio of components and the type of binding materials, pastes are liquid, buttery-like and solid.
Liquid pastes are used in to a greater extent for manual and less for mechanized grinding on machine tools. During mechanized grinding, liquid pastes are quickly sprayed by working mechanisms (discs) moving at high speed. ribbons).
Oily pastes are used for grinding varnish coatings with mechanized tools (disk, vibration, etc.) with an electric or pneumatic drive. The most widespread are grinding paste No. 289 and] cement paste.
Solid pastes are used when working on machines and automatic lines. For grinding polyester -] coatings use grinding paste VAZ-1. It uses aluminum oxide (alumina) as an abrasive material. The binder consists of] an emulsion, mineral and vegetable oils and solvents in water.
Grinding Powders
Grinding powders are dry abrasive grains that are not bound by binders. For grinding paint and varnish coatings, pumice and tripoli powders are used. The most common! is grinding with a powder with the addition of wetting liquids - kerosene, oil, water and turpentine.
Primers
Primers are suspensions of a pigment or a mixture of pigments with fillers in a binder, which, after drying, form an opaque homogeneous film with good adhesion to the substrate and coating layers. The purpose of the primers is to impregnate the surface layer of wood, make it hard and dense, fill the pores of the wood without significant shrinkage, ensure high adhesion to the base and subsequent varnish coatings
Primers are solutions of resins, nitrocellulose and plasticizers in a mixture of solvents. The composition should be easily applied to the wood surface by conventional methods (spraying, pouring, swab, brush), after application to the wood, dry quickly, be easy to sand, not dissolve when applied to it with liquid varnishes.
Primers are subdivided into joinery and painting. Joiner's primers are primers applied to the surface under transparent paint coatings that do not veil the texture of the wood.
For transparent coatings, primers are made colorless and tinted. They are composed of resins (urea, etc.), adhesives, drying oils as film-forming agents; as fillers - pumice, kaolin, talc, tripoli, chalk, starch, glass or wood flour; as solvents and thinners - turpentine, white spirit, water, etc.; as plasticizers - Vaseline oil, glycerin; as a dye for coloring to match the wood - humic and synthetic dyes.
In the manufacture of furniture, depending on the type of finish, the following primers are often used: polyester (PE-0155, PE-0129), nitrocellulose (NTs-48; NTs-0205; NTs-0140), based on PVA dispersion (PM-1). Nitrocarbamide primers (NK, BNK) are widely used.
Paint primers - primers applied to the surface under opaque paint coatings. They can contain components that cover the texture of the wood. Consists of paint primers from pigments, fillers (or without them), film-forming substances and solvents. Ocher, mummy, and red lead are used as pigments. Adhesives, drying oils, resins, varnishes are used as film-forming substances. Apply paint primers for oil paints and nitro enamels. Glue, casein, rosin-casein primers are less resistant than oil and varnish.
Fillers
Porosity fillers are compounds intended to be rubbed into the pores of wood in order to close them before applying transparent coatings, and which, like primers, form a lower layer of paint and varnish. Depending on the properties, the filler is applied to a previously primed or unprimed surface. The filler layer helps to reduce the consumption of paints and varnishes and reduce the sagging of the coating in the pores during the operation of the products.
The filler consists of a liquid part (a solution of a film-forming agent, driers and plasticizers in a mixture of volatile solvents) and a filler. It is applied to wood on flat polishing machines with washers or swabs for rubbing the filler into the pores of the wood, and manually with a swab or spatula.
Fillers can be colorless and tinted. The most widely used fillers are KF-1, KF-2, PM-11, LK, TBM.
Porous filler rosin KF-1 - a mixture consisting of finely ground tripoli powder, ether, rosin and linseed oil... After application of the filler, the surface does not need to be sanded, as the solvents contained in it do not swell the wood fibers. This filler is lightfast and has good adhesion to wood and nitro varnishes. But a negative effect is possible when the texture of some wood species is veiled.
Putties
Putties - a thick, viscous mass, consisting of a mixture of pigments with fillers in a binder, designed to fill irregularities and J smooth the painted surface.
Wood putties must be homogeneous in composition and contain highly dispersed fillers, have good adhesion to both wood and subsequent layers. paintwork, easy to apply with a spatula when spraying, forming even coverage not subject to cracking and significant shrinkage, be waterproof, dry quickly and easy to sand.
Fillers are divided into thick, designed to fill local depressions, cracks, depressions (local filling), and liquid, used for the continuous leveling of small irregularities over the entire surface (continuous filling).
According to the basic composition of film-forming substances, putties are divided into oil, glue, varnish, nitrocellulose, polyester, etc. Elutriated chalk, heavy spar, kaolin, barite, etc. are used as fillers in putties.
Oil putties are water resistant, but dry slowly and do not adhere well to wood. They are used under oil paints and enamels. Prepared at the place of consumption by mixing crushed chalk with glue and drying oil.
Lacquer, glue and nitrocellulose putties contain a large amount of volatile solvents and therefore exhibit significant drying shrinkage. As a consequence, such fillers need to be applied several times to obtain a good surface.
Putties are applied to the surface with a spatula or paint sprayer. Depending on the recipe, the following brands of putties are produced:
PF-002 red-brown and KF-003 red - a mixture of pigments, fillers, pentaphthalic and oil varnishes;
ХВ-004 green and ХВ-005 gray - a mixture of pigments, fillers and a solution of polyvinyl chloride chlorinated resin in organic solvents with the addition of plasticizers; NTs-007 red-brown, NTs-008 protective, NTs-0038 gray and white - a mixture of pigments, fillers and colloxylin solution in organic solvents with the addition of a plasticizer and oils; MS-006 pink - a mixture of pigments, fillers and alkyd-styrene varnish; EP-0010 and EP-0020 red-brown - mixtures of putty paste with a solution of epoxy resin in organic solvents with the addition of plasticizers, with hardener No. 1, etc.
When applying putties with a paint spray gun, they are brought to the working viscosity with PF-002 and KF-003 solvents - white spirit, turpentine or a mixture of white spirit with a solvent in a ratio of 1: 1, MS - xylene; NTs-007 and NTs-008 - solvent 645 or 646; ХВ-004, ХВ-005, EP-0010 and EP-0020 - with R-4 or R-5 solvent. The surface of the putty is sanded with a 4-6 grit sandpaper.
Putties are toxic and flammable materials.
Putties are thick pastes used to fill cracks and depressions on the surface of wood, intended for an opaque and less often transparent finish. Putties are prepared at the place of consumption, using glue, drying oil, resin, varnish as a binder and film-forming agents; as a filler - chalk, wood flour, fine sawdust, etc. Pigments or dyes are introduced into the putties, which give it the required color.
The best putties for wood are urea and carbinol wood, which contain by weight about 70 parts of urea glue and about 30 parts of wood flour or fine sawdust. These putties are cold cured at room temperature.
A fast-hardening putty is prepared from magnesia-caustic powder mixed in 1 aqueous solution of magnesium chloride by introducing fillers into the liquid part with continuous stirring until a mixture of the desired consistency is obtained.
For a transparent finish, putties are prepared using the appropriate varnish and from small sawdust of the type of wood on which the defects are to be repaired.
Components of paints and varnishes. Dyes are powdery mixtures of colored organic substances that are soluble in water, alcohol and other organic solvents and form transparent solutions that change the color of the wood without darkening the natural texture. Dyeing is used to enhance the natural color of wood, imitate low-value species for valuable and tint varnishes. For dyeing wood, dyes are usually used in the form of aqueous and less often alcohol solutions of 1-3 percent concentration.
Dyes
Dyes should be lightfast, have a bright color, high dispersion, do not hide or darken the wood texture, and easily dissolve in solvents - water, alcohol, acetone or other organic solvents.
By origin, wood dyes are divided into two groups - natural and synthetic.
From natural dyes in the furniture industry, a brown dye called walnut stain or stain is used. The dyes in the dye are humic acids. Humic dye dissolves well in water, colors wood in an even brown color of various shades, has high lightfastness, better than most synthetic dyes. It mixes well with synthetic dyes of direct and acidic groups.
Synthetic dyes are complex organic substances obtained from coal tar. On the basis of solubility in various solvents, dyes are divided into water-, alcohol- and fat-soluble, wax, etc.
In relation to textile fibrous materials, dyes are divided into acidic, nigrosine, direct, basic, mixed, etc. For dyeing wood, acidic dyes and nigrosine are mainly used.
Acid dyes are sodium, potassium or calcium salts of organic acids. These dyes do not dye cellulose fiber, but they dye well the lignin and tannins that are part of the wood. They paint wood in bright and clean colors and have sufficient lightfastness, dissolve well in water, and can be mixed with each other.
Table. Dyes for surface dyeing of wood
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Dyes |
Painted wood species |
Color tone and simulated breed |
Dye concentration in solution,% |
|
Reddish brown No. 3 |
Red tree |
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Reddish brown No. 4 |
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Light brown No. 5 |
|||
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Light brown No. 6 |
Beech, birch |
||
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Dark brown No. 3 |
Birch, oak |
||
|
Yellowish brown No. 10 |
Ash, oak |
Light oak |
|
|
Orange brown No. 122 |
|||
|
Walnut brown No. 2 |
The industry produces the following acid dyes for dyeing wood: yellow, dark red, brown, dark brown, reddish brown No. 1, 2, 3 and 4, light brown No. 5, 16, and 7, 16 and 17, dark brown No. 8, 9 and 15, yellowish brown No. 10, nut brown No. 11, 12, 13 and 14, orange-brown No. 122, red No. 124, etc. In table. the wood species suitable for staining with different dyes of a certain concentration are given.
The variety of dyes that color the part in the process of reaction with the tannins of wood include mordants - iron vitriol, which gives a color from gray to black, copper sulfate, sodium chromium peak, potassium chromium peak, copper chloride, which paint wood in yellow-brown tones. This dyeing method is called pickling.
Pigments are finely ground powders of one color or another. Pigments cannot fix themselves on the surface of the product to be painted and therefore are always used in a mixture with a solution of some film-forming material (glue, oil) that fixes the pigment powders on the surface of the product. Pigments are added to the binder to produce a lightfast opaque coating. Ready-made compositions from a mixture of a pigment with a film-forming solution are called paints (glue, oil). Pigments are inorganic and organic.
After drying, the paint applied to the product forms a colored opaque film that hides the color and structure of the painted material underneath.
Pigments are used in oil and enamel paints for opaque coloring of kitchen, children's, medical furniture, cars, agricultural vehicles, windows, doors and are added to primers for transparent coatings.
Organic volatile liquids designed to dissolve film-forming agents (resins, ethers, cellulose, oils) and plasticizers and bring their solutions to working viscosity are called solvents.
Thinner No. 646 is used to dilute nitro varnishes, nitro enamels and general purpose nitro fillers. Store the diluent in a dry, unheated room, protected from direct sunlight.
Thinner RE-7V is used for diluting nitroenamels; RE-10V-for breeding oil paints, thick-grated white, thick-grated paints on natural inorganic pigments.
Solvent R-219 consists of acetone, toluene and cyclohexane taken in a 1: 1: 1 ratio. It is intended for thinning polyester materials - varnishes, enamels and putties.
Thinner No. 648 is used to smooth out streaks and scratches by spraying with nitro-enamel coatings after grinding.
Solvent furniture varnishes(RML) serves to dilute nitrocellulose varnish NTs-222 and thread polish NTs-314 and bring them to working viscosity. adhering to the materials of the product is called film-forming. These include drying oils and natural and synthetic resins.
Oily oils are processed products of vegetable oils, fats and organic products. They are used for preparation and dilution of paints and priming of the painted surface. The drying oils are divided into four subspecies: natural, compacted, synthetic pure and synthetic modified.
Natural drying oil is produced from linseed or hemp oil with the addition of driers. It is used for the preparation and dilution of thickly grated paints, as well as independent material for painting works.
Drying oils are prepared by heating drying oils with metal oxides (desiccants) or by oxidation, which consists in blowing air through the oil. Natural drying oils- high quality film-forming material for outer coatings. Guarantee period storage of drying oil for 24 months.
Oksol varnish is a solution of oxidized vegetable oil and driers in white spirit. Depending on the raw materials used, drying oil oxol is produced in the following grades: B - from linseed and hemp oil, intended for the preparation of oil paints used for outdoor and internal works, with the exception of floor painting;
PV - from sunflower, soy, corn, grape, camelina oils; intended for the manufacture of oil paints used for interior painting works, except for the coloring of the floors.
The approximate composition of the drying oil oxol (in%): oil - 50.1 drier - 3, white spirit - 47. The guaranteed shelf life of drying oil is 12 months. Oksol varnish is
fire and explosive material. Natural dried vegetable oils for the preparation of drying oils are in short supply, therefore, artificial drying oils are produced for these purposes. Such drying oils are glyphthalic and pentaphthalic, which are 50% solutions of medium fat glyphthalic resin or fatty pentaphthalic resin in white spirit with the addition of a desiccant. Artificial drying oils also include shale, synthetic modified drying oils and combined drying oils: K-2, K- 3, K-4, K-5 and K-12.
Linseed oil K-4 is used to dilute thick-grated paints intended for interior work. The consumption of drying oil when diluting thick-grated paints is 20-30% of the paint mass. Drying time at a temperature of 18-22 ° C -24 hours. It is stored in a carefully closed container, it is flammable.
Varnish
Lacquer is a solution of film-forming substances in organic solvents or in water, which, after drying, forms a solid transparent homogeneous film.
Depending on the nature of film formation, varnishes are separated into forming films only due to the evaporation of solvents (for example, alcohol, nitrocellulose), forming films due to chemical reactions of polymerization and polycondensation, as a result of which they become insoluble (for example, oil, polyester, urea formaldehyde).
Lacquer films protect products from external influences, give them a beautiful appearance, waterproof properties, etc. On the surface of the elements, a lacquer layer should be obtained that is uniform in thickness, color and gloss, which has good adhesion to wood or underlying layers of primers, fillers and fillers.
The names of varnishes are taken for solvents - alcohol or for film-forming substances, for example, oil, nitrocellulose, polyester, polyurethane, perchlorovinyl, etc.
Alcohol varnishes are resin solutions in volatile solvents. The main solvent for this group is ethyl alcohol. Films of alcohol varnishes form when the solvent evaporates and can be re-dissolved in it. Alcohol varnishes are applied with a brush or swab, and a very thin and transparent film with a high gloss is formed, but not sufficiently water and frost resistant. Repeated application of alcohol varnishes and insufficient durability are the main reasons for their limited use.
The industry produces shellac alcohol varnishes, rosin-shellac, rosin, and carbinol varnishes. Shellac varnishes are the most widely used of them.
Oil varnishes - solutions of resins (natural or synthetic) in drying and semi-drying oils, solvents with the addition of desiccants. Drying oils are used as the main components - linseed, hemp, tung, and as resins - rosin, copal and glyphtal. Solvents are turpentine and white spirit, xylene, etc.
Due to the fact that the films formed by oil varnishes dry very slowly (48 hours or more), to reduce the drying time, special substances are introduced into the varnishes - driers in an amount of no more than 7-10% of the mass of oils. But even with the introduction of desiccants, the drying times for oil varnishes are several times longer than the drying times for nitro varnishes or shellac varnishes, which limits their use in finishing wood products.
Oil varnishes are applied with a brush, swab or spray. Films of oil varnishes have good elasticity, frost and water resistance.
The industry produces general and special oil varnishes. For the finishing of wood products, varnishes of general consumption, light 4C, 5C and 7C and dark 4T, 5T and 7T, are predominantly used. Drying time for varnishes 4C, 4T - 36 hours, 5C, | 5T - 48 h, 7C, 7T - 24 h.
Special oil varnishes include varnish No. 350 - for flooring, No. 74 - for the preparation of putties, No. 331 "Frost" - for interior decorative works... Nitrocellulose varnishes (nitro varnishes) are solutions of varnish colloxy
on various brands, resins and plasticizers in a mixture of volatile organic solvents. They are widely used in the decoration of various joinery.
The coatings formed by nitro varnishes dry quickly as a result of the evaporation of solvents, forming sufficiently hard, resistant and elastic films that can be polished. Volatilization of solvents occurs at a temperature of 18-20 ° C and is significantly accelerated when drying in a chamber at a temperature of 35-50 ° C.
Nitro lacquers can be subdivided as follows
way: transparent - cold and hot application; matting; acid hardening - transparent and matting. Cold-applied transparent nitro-lacquers NTs-218, NTs-221, NTs-222, NTs-224, NTs-228, NTs-243; lacquer NTs-218 can be applied to the wood surface with a swab. All varnishes, without exception, are applied by spraying, and varnishes NTs-222, NTs-224 and NTs-218, except for the indicated methods, are applied in bulk. These varnishes are brought to working viscosity with solvent No. 646, with the exception of NTs-223 varnish, for which RML-315 solvent is used. Hot-applied nitro varnish includes NTs-223 varnish. The heating temperature of the varnish is 70 ° C.
Alkyd-urea varnish MCh-26 is used for covering floors, it is applied with a brush or by spraying; drying time 3 h.
Polishes
Polishes are solutions of low concentration solid polishing resins, colloxylin and plasticizers in a mixture of volatile organic solvents. The dry residue in polishes is 8-15%.
The polishes are used to create an even, high-gloss transparent finish that brings out and deepens the natural texture of wood.
There are two main types of polishing with varnishes: polishing with varnishes for wood (carpentry polishing); polishing with polishes by. shellac or nitro lacquer coating.
Distinguish between alcohol polishes and nitropoliters.
Alcoholic polishes containing shellac in solution are called shellac. Shellac polishes are often prepared at the point of consumption by dissolving shellac in ethyl alcohol, then settling and filtering the solution.
The chemical industry produces the following alcohol-shellac polishes: No. 13 (light brown), No. 14 (dark brown), No. 15 (red-raspberry color), No. 16 (black-blue, color). These polishes are used for polishing shellac, nitrocellulose and oil films.
Nitropoliters form a more resistant coating than alcoholic ones. They are used for polishing nitro lacquer coatings after smoothing or sanding. The first stage of polishing is carried out with nitropolite diluted with RML solvent in a ratio of 1:10
Nitropoliters are nitroshell and cellulose nitron. They are used for the final polishing of nitro lacquer films. At the place of consumption, nitroshellic polish is prepared by mixing nitro polish NTs-314, shellac polish and RML solvent in a ratio of 1: 1: 1.
Paints are suspensions of pigments and mixtures of pigments with fillers in drying oil, emulsion, latex, forming an opaque homogeneous film after drying. Depending on the type of film-forming substances, paints are divided into glue, oil, emulsion, enamel, etc.
When pigment film-forming substances are added to the solutions, the coatings are given opacity and a color that depends on the color of the pigments. Pigments also change other properties of the coatings.
Usually, protective properties paints are much higher than the protective properties of the corresponding films of pure film-forming (varnishes). Increased protective properties of paints are obtained due to the introduction of inorganic pigments.
Paints and the coatings they form must meet a number of requirements. except general requirements relatively good filling, fast drying, good adhesion and resistance to external influences, they should have a certain color, degree of dispersion of solid particles (pigment and filler), high hiding power and stability during storage.
Oil paints are mixtures of pigments in vyhayuschih oils. Some call it dry vegetable oils(linseed, hemp, tung) capable of forming hard and elastic films as a result of oxidation by atmospheric oxygen. Linseed oil is the most widely used for the prepared paints.
Oil paints take a long time to dry. Typically, the drying time of coatings at a temperature of 20 ° C lasts at least a day. Therefore, oil paints are of limited use in the decoration of wood products. To accelerate drying, driers are introduced into the drying oil during its preparation.
The chemical industry produces thick-grated oil paints, which are a paste-like mass of pigments rubbed with drying oil, as well as ready-to-use, diluted to a working consistency with the same drying oil, turpentine and white spirit; used mainly in construction.
The group of thickly grated oil paints of general consumption includes lead, zinc and lithopone whitewash, lead and zinc greens, artificial cinnabar, red iron, mummy, ocher, etc. The degree of grinding of the pigment is indicated by numbers. The smaller the number, the finer the grind and coverage of the paint. Depending on the composition of the dry matter, paints are subdivided into grades (grades).
To the working viscosity, thick-grated oil paints are diluted with linseed oil. The amount of drying oil required for this depends on the type of fineness of the grinding of the pigment and ranges from 0.25 to 0.4 kg per 1 kg of thickly grated paint.
In order to accelerate drying, diluted paints are added from 5 to 10% desiccant. Turpentine or white spirit can be added to increase the pouring ability of oil paints, but this reduces the viscosity, strength of the coating and its gloss. Some of the oil paints (lithopone whitewash, red lead, ocher, mummy) are produced ready-to-use.
Most oil paints can be mixed with each other to obtain additional colors, but lead paints cannot be mixed with paints containing sulfur compounds, for example, ultramarine, lithopone, cinnabar.
Water-based paints intended for indoor work on wood, plaster and other porous materials, produced in 10 different colors. Paints are not recommended for rooms with high humidity. They are applied to the surface by pneumatic spraying, brush or roller.
Depending on the composition of the paint, the following brands are produced: E-VA-27, E-VA-27A - based on polyvinyl acetate dispersion; E-KCh-26, E-KCh-26A - based on butadiene latex. Titanium dioxide is used as the main pigment for E-VA-27A and E-KCh-26A paints, and lithopone is used for E-VA-27 and E-KCh-26 paints.
Water-based paints used for painting buildings on brick, concrete, plastered, wood and other porous surfaces are produced in 17 colors. They retain their properties in temperate climates for at least 5 years. The paints are applied with a paint sprayer, roller or brush at a temperature not lower than + 8 ° С.
The following paints are produced: E-AK-111 - based on copolymer acrylate dispersion; E-VA-17 - based on polyvinyl acetate dispersion; E-VS-17 - based on a copolymer of vinyl acetate with dibutyl maleate; E-VS-114 - based on a copolymer of vinyl acetate with ethylene; E-KCh-112 - based on styrene-butadiene latex.
Enamels are suspensions of pigments or mixtures of pigments with fillers in varnish, which, after drying, form an opaque solid film with various gloss and surface texture. Purpose of enamels - opaque finishing of wood products, including furniture, windows, doors.
Enamels should have high hiding power, fine grinding of pigments, good flow on the surface, good adhesion to wood or a primer, sufficient hardness, elasticity, light and water resistance
Depending on the composition of the main film-forming substances, oil, alcohol, nitrocellulose, pentaphthalic, alkyd-styrene alkyd-urea, polyester, perchlorovinyl, polyurethane enamels are distinguished.
Oil enamels are mixtures of pigments with oil varnishes. The following enamels of this group are used for finishing wood products: oil-glyphthalic, pentaphthalic, moire, fixole and emulsion enamels.
Oil-glyphthalic enamels of various colors are used to decorate products used indoors. The coatings formed by these enamels are not smooth enough; their drying time at a temperature of 20 ° C is 48-72 hours.
Pentaphthalic enamels of the PF brand are made on fatty pentaphthalic varnishes. They form smooth, flexible and weather-resistant coatings. At a temperature of 20 ° C, the coating dries up in 48 hours.
Moire enamels form a complex pattern after drying. Intended for decorative finishing products simple designs... The enamel is brought to working viscosity with white spirit or xylene. Drying time of coatings at a temperature of 80 ° C - 12-14 hours.
Fixole enamels are made on a greasy oil varnish containing at least 40% tung or linseed oil. The coatings formed by the fixol have high weather resistance and semi-mirror gloss. To the working viscosity, the enamel is diluted with a composition consisting of 33% turpentine and 67% fixole varnish. Drying time at 20 ° C - 24 hours.
Emulsion enamels are a suspension of pigments and an emulsion consisting of a varnish-oil base and water with the addition of organic solvents and driers. Apply for interior decoration premises for plaster and wood. Drying period of coatings at a temperature of 20 ° C - 24 hours.
Nitrocellulose enamels are a suspension of pigments in nitro varnish. These enamels dry quickly, have good flow, sufficient coverage, form shiny resistant coatings that are well sanded and polished.
Nitroenamel NTs-25 is produced in 19 colors. It is used for painting wooden surfaces operated indoors. Enamel is applied to the previously primed surface by spraying or pouring. Dilute the enamel to working viscosity with solvents No. 645, 646. Drying time of the enamel at a temperature of 18-20 ° C is 1 hour.
Glyphtal enamel NTs-132 is used for painting primed wooden parts and products used in atmospheric conditions and indoors. Enamel NTs-132 is produced in white, yellow, blue, red, black and other colors. The time for complete drying at a temperature of 18-22 ° C is 3 hours. Dilute to working viscosity with solvent No. 649.
Enamels NTs-11 and NTs-PA 52 colors are intended for painting the previously primed or filled surfaces of products used in atmospheric conditions and indoors.
Enamels NTs-11 are diluted to working viscosity with solvents No. 646, 647, 648. Enamel coatings have the ability to grind and polish with the formation of a high-gloss surface. The guaranteed shelf life of enamels is 6 months from the date of manufacture. The enamel is applied to the surface by pneumatic spraying up to five layers. Application by brush is allowed. The drying time of the enamel at a temperature of 20 ± 2 ° C is not less than 10 minutes for each layer, the last one - not less than 1 hour. To give a mirror shine, the film is treated with polishing paste of type No. 291, VAZ-2, polishing compound such as VAZ-03.
Bee and sheet finishing materials based on impregnated papers. Facing film and sheet materials They are divided into transparent and opaque, which have their own adhesion to the substrate - wood material - and do not have it, require subsequent finishing after gluing and do not require it.
One of the promising finishes furniture products from wood-based materials - pressing of paper-based film materials (lamination). With this method, protective decorative coating in most cases it is created by means of films impregnated with synthetic resins.
The modes of overpressing films depend on the material on which the film is glued, as well as on the resins with which the paper is impregnated. These films are glued by melting the resin in them and do not require prior application of glue to the elements. Films based on paper impregnated with urea-formaldehyde resins can be pigmented, non-pigmented and decorative with imitation of the texture of various wood species or other patterns. The use of such films provides a replacement for sliced and peeled veneer. Films based on imitated wood grain papers are commonly referred to as synthetic veneers.
Pigmented and non-pigmented monochromatic films are intended for adhesion to wood-based materials as a primer under enamel. After gluing, the films are sanded and finished with enamels. As a result of their application, the consumption of putties and primers is reduced, and the number of enamel layers is also reduced.
The method of facing boards with material from a roll (lamination method) has become widespread due to the fact that it provides a high-quality decorative coating. After varnishing, textured paper with a printed pattern (imitating wood species) is more similar to valuable wood and does not require finishing. A mixture of urea-formaldehyde resin and polyester emulsion, etc. is used as an impregnating solution.
For the manufacture of films, special paper is used: textured roll, decorative with printed pattern, paper is the basis of synthetic veneer.
Materials with partial polycondensation of resins are produced in two types: facing films and films-sublayers. After impregnation, the films are dried to such a stage when the resin completely loses its tack, but can melt under the influence of heat and pressure and then polycondensate. Therefore, the films are glued during veneering without glue. Resin
during the manufacture of the film, it is not cured, but dried. The cladding film is used for veneering chipboard (lamination) and for the manufacture of decorative paper-laminated plastic. For the production of furniture, furniture parts from particle boards, lined with films based on thermosetting polymers - laminated parts. The thickness of the parts is 13-22 mm with a graduation of 1 mm.
Facing sheet materials based on impregnated papers with a deep degree of resin hardening are divided into types A, B, C, D.
Films of type A are finished with nitrocellulose, polyester varnishes and enamels. They finish all the layers of the shield parts. Resinning - 50%.
Films of type B are used for facing all layers of shield parts. They are finished with polyester varnishes. The resinification of the film is 62%.
Films of type C are lined with the inner surfaces of products and finished with nitro varnishes and enamels. Resinning - 50%.
Films B and D in kitchen furniture do not use. Films of type C are faced with the inner surfaces of products and finished with nitro-varnishes and enamels.
The dimensions of the film sheets are set by agreement with the consumer.
Films with a deep degree of resin hardening are distinguished by the fact that during manufacture, after impregnation, they undergo prolonged drying at high temperature, as a result of which the impregnating resins are almost completely cured. It is necessary to use glue for gluing films.
Roll materials with deep resin cure rates have been widely used in recent years. Facing roll material is made of the following types: RP, RPL, RPT, RPE, RPLE, RPTE, RPKhP.
Film of RP type has no paint and varnish coating, RPL - with paint and varnish coating, RPT - with embossed pore pattern; films with the letter E are distinguished by increased elasticity. In the manufacture of films of the RPKhP type, relief pores of the wood pattern are obtained without the use of an embossing calender installation as a result of the chemical interaction of ingenious paint with the film.
Films RPL, RPT, RPLE, RPTE are finished with acid-curing varnish ML-2111PM, nitrocellulose varnish NTs-2102.
Depending on the type finishing material and the quality of the film coating is divided into subgroups (A, B, C) and categories (1,2, 3).
Films are produced in widths of 1000, 1510, 1770, 1850 mm and are packed in rolls with a diameter of 400-500 mm.
Edging materials based on papers impregnated with thermosetting resins are made with a deep degree of resin cure. The front surface has a protective and decorative coating and does not require finishing.
The industry uses the following types of edging material: strip - MKP-3, MKPPE-2; tape roll - MKR-1, MKR-2, MKR-3, MKRMF-1, MKRPE-2. The number in the film grade indicates the number of layers of material.
According to the condition of the surface, the films are produced glossy, matte, semi-matte, smooth, with embossed and printed patterns.
Edging materials are produced with a width of 14-15 mm, a thickness of 0.27-0.5 mm, a length of 2-3.5 m, 500 and 600 m.
Decorative paper-laminates (DBP) are made by hot pressing several (3-15) layers of paper impregnated with artificial thermosetting resins. These plastics can be in the form of sheets of various sizes and in the form of rolls. The facing layers of paper are impregnated with melamine-formaldehyde resin, and all the rest with phenol-formaldehyde. In addition, to obtain a high gloss surface, a layer of melamine resin impregnated paper is placed on the outer decorative paper sheet when forming the bag. The surface of the sheets can be glossy or matte, single or multi-color
Depending on the quality of the front surface and physical and mechanical parameters, plastic is subdivided into grades: A - for use in conditions requiring increased wear resistance (finishing of horizontal surfaces); B - for use in less severe conditions (finishing of vertical surfaces); B - for use as an ornamental material.
For the front surface of the plastic, the following symbols are used: G - glossy, M - matte, O - plain, P - with a printed pattern, 3 - s protective layer... In the designation of plastic, there may be numbers that indicate the color and printed pattern according to the catalog - the standard.
For veneering, polyvinyl acetate adhesives with sufficient water resistance are used.
Decorative laminate is an excellent finishing material. High aesthetic qualities of particle board, pure juicy color, the ability to imitate any pattern, including patterns of valuable wood and stone, various surface textures combined with great strength, resistance to scratches, hot detergents, various chemicals and high temperatures make it very effective when decorating kitchen, medical, children's and built-in furniture, commercial equipment, public transport salons, in construction when cladding walls, partitions, doors, etc.
Plastic is produced in sheets 400-3000 mm long, 400-1600 mm wide with intervals between adjacent dimensions 25 mm, thickness 1; 1.3; 1.6; 2; 2.5; 3mm. Sheets with a thickness of 1 mm are made with dimensions not exceeding 1500x1000 mm.
Polymer based materials
Release polymer materials in the form of sheets, films, nonwovens, artificial leather. PVC decorative finishing films are made for various industries. It is intended for finishing previously prepared internal surfaces of the walls of residential and public buildings, door leaves, built-in, children's and other furniture, panels, interior elements of premises and salons in the aviation and automotive industries.
The film is produced in two types: PDO - without an adhesive layer and PDSO - with an adhesive layer on the back, protected with special paper. The film is produced in rolls of the following sizes: PDO - 150m long, 1500-1600mm wide, 0.15mm thick; PDSO - 150m long, 450-500mm wide, 0.15mm thick, as well as 80m long, 900mm wide and 0.15mm thick
Surfaces covered with PDO and PDSO films can be wet cleaned with water at room temperature. Do not use solvents, soaps and detergents.
PVC films have poor adhesion to wood, therefore they are glued with perchlorovinyl glue, aqueous dispersion adhesives, latexes, hot melt adhesives.
Textured PVC self-adhesive films are also produced, on the non-face surface of which a sticky layer is applied. Such films are glued by rolling and lightly lapping to the wood with a roller, a bar with rounded edges or a lapping hammer.
The widespread use of polymer film materials is due to their relatively low cost, good physical and mechanical properties, high decorative effect and the ability to obtain surfaces that do not require subsequent finishing.
Sheets of polymer materials are almost never used for cladding furniture products, since they are poorly printed on and they do not adhere well. Polymeric materials with a thickness of up to 0.25 mm and a width of more than 100 mm are usually considered to be film materials. Narrow material is called ribbons. A thicker material of sufficient flexibility to roll it into a roll is also considered a film.
Films are available in one, two and three layers. The printed pattern is well applied to single-layer films, their surfaces are convenient to finish, but when lining, all the irregularities of the base plate appear. Therefore, for cladding, a material with a thickness of at least 0.15 mm is used. In a double layer film, the top layer is thin with a printed pattern and a finished surface. The bottom layer is thicker - it is duplicated with a thin decorative film.
Three-layer films are obtained if a thin transparent film, resistant to external influences, is additionally applied to the decorative film.
For cladding, porous monolithic films are used. In these films, the outer surface is solid - monolithic, and the middle layers are porous. The surface of the films is well decorated. It can be colored, background, metallized, with a printed pattern of any kind, with embossing. The most relief embossing can be applied to a porous monolithic film.
The film can be matte, glossy, even or with a relief pattern under the skin, etc. The thickness of the films is 1.2-1.5 mm, width 600-1300 mm, length 30-150 m in the form of rolls. Frost resistance -30 ° С. Heat resistance not less than 100 ° С.
Films are used for facing the layers of panels of furniture for a bedroom, nursery, etc.
Polyvinyl chloride (PVC) films for facing are produced with a smooth and embossed surface, covered with a finishing layer, glossy and matte, monochrome or with a printed pattern of wood texture (mahogany, walnut, ash, etc.). The thickness of such films for layers is 0.15-0.23 mm, for edges 0.3-0.4 mm, width for layers 1200-1870 mm, for edges 14-15 mm.
Films based on polyvinyl chloride resin are produced in a large assortment. The composition of compositions based on PVC is as follows (mass parts): polyvinyl chloride-100, stabilizers - 0.5-5, plasticizers - 5-80, pigments and fillers - 0-10.
Physical and mechanical PVC properties films depend on the amount and type of plasticizer. As it increases in the composition, the hardness and strength decrease, but frost resistance, the ability to crack, and elasticity increase. Depending on the content of the plasticizer, films are distinguished: rigid (0-5% plasticizer), semi-rigid (5-15%) and soft (more than 15%). Rigid films are characterized by good wear resistance, hardness, strength and heat resistance.
PVC-ABS films have greater rigidity, heat resistance and less thermal shrinkage. The composition of the film composition is as follows (mass parts): polyvinyl chloride - 100, ABS plastic - 50, stabilizers - 4, plasticizers - 25, pigments and fillers - 10. In the furniture industry, they are used for facing front, front, internal surfaces and edges of furniture parts.
After sanding, or other steps preparatory process, to get smooth, flat surface use pore fillers. However, the resulting effect directly depends on the type of surface, the type of wood, and on what result you want to achieve.
Pre-treated surfaces with stains should preferably be pre-treated with a sealer (liquid filler or primer) in order to prevent the release of oils from the pores. No other processing is required. Unpainted surfaces must be primed (with special primers or varnish diluted with a solvent). If you plan to further apply polyurethane varnish make sure that the filler and primer components do not conflict with each other. This will prevent the putty from falling out of the pores. Let the primed product dry and sand the surface with fine-grained sandpaper. Remove dust from the surface and start working with filler.
To apply a pasty filler, add a solvent to it (according to the instructions), bringing it to a consistency reminiscent of its viscosity butter... Remember that wood with deep open pores requires a less viscous composition than one with small pores. Apply the filler with a clean brush, working first along the grain of the work piece and then crosswise.
Let your putty stick to the surface, let it dry and shrink a little. According to most instructions, this period is about 15-20 minutes. Then, the rest of the filler is removed using a coarse cloth. At this stage, work is carried out against the fibers of the tree, perpendicular to their direction. Remember - you are removing material from the surface, but you must leave it in the pores. Next, the wood is gently wiped with a clean and dry cloth, and the putty is given the opportunity to gain strength within 24 hours.
Subsequent processing.
Your treated wood should look clean. If you notice a light, hazy coating remaining on the surface, be aware that these are small particles of filler. This plaque can be easily removed by sanding with fine grain paper. Be careful not to remove the filler from the pores or damage the stain.
As we remember, we took a frame for a photograph or painting as an example. More precisely, using the example of making such a frame, we began to consider the stages of processing a wooden blank.
So, after bleaching, the master decided to once again process the blanks with sandpaper. This will not make the wood worse, but a pile will appear on its surface, which will interfere with the application of paintwork. Raising the pile can be "provoked" by wiping the workpieces with a damp sponge, after which the product should be dried and sanded.
The next step wood processing is the application of a primer to its surface.
First of all, you need to choose a primer that will match the intended finish (transparent or opaque). Since we have decided that the frame will be "exposed" to a transparent finish, then the primer must be appropriate. We spent a lot of time on the topic of "primer", but little was said about primers intended for application to wood. To the previously said we add the information that the Chemical Encyclopedia "shared" with us. It says the following about primers for wood: "... primers for wood should fill the pores on the surface of the wood, without being drawn into them when the layer dries. containing pigments and fillers.As a primer under opaque (opaque) coatings on wood, insulating primers for metal that do not require hot drying can be used.To prime wood of large-porous species, so-called fillers are used (for example, a concentrated suspension of highly dispersed glass powder in a solution of a mixture of flaxseed oils with glycerin ester of rosin in a high-boiling solvent), which are rubbed with a swab. " To what was said in the Encyclopedia, it is worth adding that primers on wood can be applied both with rollers and brushes. Primers perform not only protective functions, but also characteristic colors. With the help of primers, for example, ordinary spruce can become indistinguishable from mahogany. Many primers have antiseptic and insect-targeting properties.
So, the wood is treated with a primer and after drying it "waits" further action home master... And he is so involved in the process that he wants to make his product in the best traditions. And now my hands are reaching for the varnishes. Here we must tell the novice master "stop" and tell him that "soon the fairy tale will tell, but not soon the work will be done." And the matter should be done in accordance with the unwritten (and nowadays, written) rules. If in the process of priming primers were used that do not completely fill the pores of the wood, that is, not special primers, it is necessary to apply a composition called "filler". It is these compounds that must be present on the surface of the wood before processing it with paints and varnishes. By purchasing these formulations, the master should pay Special attention whether the filler is colorless or of any color. This is important for the simple reason that, intending to preserve the "pristine" color and structure of the wood, a novice craftsman may "miss" and cover the workpiece with a colored filler, which, in turn, will interfere with the plan.
After the filler is applied to the product, you need to wait until it dries. Now you can proceed to the next stage of processing (either varnishing or polishing). The difference between varnishing and polishing lies in what exactly the surface will be treated with: varnishes (for the first case) or polishing liquids (including polish).
If we talk about varnishing, then it should be noted that in addition to the varnishes themselves, there should be solvents 646 and 647 in the home craftsman's workshop, which were described in the articles on paints and varnishes. These solvents are needed to add them to a thickened varnish. If a novice craftsman wants to see the frame made (and we remember that we are talking about wood processing on the example of a photo frame) varnished and shiny, then you should ask if this coating will really give shine. The fact is that there are matte varnishes. They form a film on the surface of the wood, but at the same time do not have a characteristic gloss. As for varnishes that give the surface a shine, their use does not guarantee that the surface will actually become shiny. And the point here is not in the varnish, but in how much solvent these varnishes were diluted. The more solvent is added, the more chance of a matt finish. In addition, the application of varnish in thick layers will also not add gloss to the surface, but, on the contrary, will make it matte.
Varnishes, regardless of whether they are glossy or matte, are applied to the surface of the wood with a swab, brush, or with a spray gun. Speaking about specific types of paints and varnishes, we note that shellac varnish is used most often. It has a brownish yellow tint and is glossy when applied to the surface. True, there are also "cloudy" shellac varnishes, which include shellac wax. The coating is applied with a swab, and experts recommend not dipping the swab into a container with varnish, but pouring the varnish onto the swab. The varnish is applied along the grain of the wood with fairly fast movements. Each stroke should overlap the borders of the previous stroke.
We will talk in more detail about, which include shellac varnish, as well as other varnish coatings, in the next part of the article.
Alexey Kaverau
The article uses photos of the sites: belabraziv, kolorit-rt, auto43, krovli100, armada-skit
Wood is a "gentle" material that requires special treatment not only during operation, but also during its preparation. To wooden interior details served for a long time and did not lose nice looking , they need to be covered special means... One such product is a filler.
Wood - organic material, and upon closer inspection, you can see that it is far from solid, but covered with many small pores... If the pores are not filled, the varnish may lie unevenly, or even sink altogether. It is in order to get rid of this feature, to make the material even and smooth, that a filler is needed.
The filler is a mixture of a thick consistency on a water or oil basis, usually consisting of a filler (for example, silica) and a pigment substance. Quality filler will rub easily on wood, will not delaminate or undergo strong shrinkage, when drying or during application. Not to be confused filler and primer! Of course, the soil mix is also important for wooden products, but it performs a completely different function - it protects wood from rot and the appearance of harmful bacteria or bugs in it, and also improves adhesion.
Color palette fillers are very wide. With the help of a filler of one shade or another, you can visually age the wood, make its pattern more contrasting, or, conversely, hide it. But it is important that the filler pigment does not dissolve in the varnish with which the product will subsequently be covered. This, firstly, will look unaesthetic, and secondly, it may indicate the low quality of the purchased filler.
Filler selection criteria
One of critical factors that need consider when choosing a placeholder for wood, this is the adhesion (ability to adhere to the surface) of the selected mixture. This adhesion does not apply to the wood itself, but to the filler. Once dry, some mixes may simply start to "detach" from the wood. One has only to lightly push the wood or somehow influence it, the mixture will begin to pour out of the pores. In addition, wood, with an increase or decrease in humidity in the room, tends to slightly change its volume, and this should also be provided by the filler manufacturer. That is, the mixture should retain a slight elasticity even after drying. A low-quality filler, from a change in the volume of wood, can simply settle inside the pores, exfoliate or deform the material.
And the most basic rule. If the filler is really high quality, it will be compatible with subsequent coatings applied to the wood (varnish or paint). A bad mixture can cause unpleasant haze on the surface of the wood, or even peeling of the varnish!
Remember that even the highest quality filler can ruin your repair if not used as instructed.
Fillers are usually available as a thick paste, thinned to the desired consistency prior to application. Some manufacturers offer special thinner fluids, but white spirit or thinner gasoline, if used for the same purpose, will cost much less. White spirit slows down the drying of the filler, allowing more time to work with large parts. Solvent gasoline is convenient for processing small parts, accelerating the drying of the composition.
Check the color of the filler on a test piece sanded and primed at the same time as the main surface to be treated. If you are not satisfied with the color, add the appropriate pigment (see “Choosing a Filler Color”). We have tinted the "natural" filler with Mixol pigment paste, but other suitable formulations can be used.
Pore filling
Pour the diluted filler onto the wood to be finished and spread it evenly with a plastic trowel or scraper across the grain. When rubbing the filler into the pores of the wood, work carefully to avoid scratching the primer layer. Simultaneously with the main plane, fill in the pores on the profiled edges and other visible surfaces (photo A). Continue to scrub across the grain to remove thick smears, lumps and excess compound.
After evaporation of the solvent, the treated surfaces sometimes become dull and dull (photo B). In this case, you need to remove the excess dried composition. To do this, wipe the surface across the grain with a coarse cloth (photo C), not allowing the composition to be removed from the filled pores of the wood. Turn over clogged fabric and work with the clean side. Finish wiping only when no matte, dull spots or transverse streaks are visible in the reflected oblique light (photo D).
Porous filler compositions can vary significantly in drying speed, but varnish can be applied no earlier than three days later, since solvents in varnish coating may soften the filler.
With a 320 grit abrasive sponge, lightly sand the surface to avoid damaging the thin primer. Apply a second coat of the same impregnation primer and, with side lighting, feel the surface with your fingers for any gaps.
So tree species large pores such as oak may require re-filling and priming.
If you are satisfied with the smoothness of the resulting surface, apply two coats of topcoat. Smooth out the last layer by sanding with 320 grit paper wrapped around a flat hard sanding pad (a plank or plywood 75x120 mm with felt or felt glued on will do the job successfully). Then apply a third top coat and polish to the desired shine. Mirror gloss can be obtained by additionally applying a layer of wax over the varnish film, followed by polishing.