Colloquial name for polymers based on acrylic acid. Dictionary of the designer "A

Polymers derived from acrylic and methacrylic acids, or so-called polyacrylates, represent an extensive and varied class of polymerization polymers widely used in the art.

The significant asymmetry of the molecules of acrylic and methacrylic esters determines their greater tendency to polymerization.

Polymerization has a radical chain character and takes place under the action of light, heat, peroxides and other factors that initiate the growth of free radicals. Purely thermal polymerization proceeds very slowly, and this method is rarely used. Usually polymerization is carried out in the presence of initiators - benzoyl peroxide and water-soluble peroxides. There are three main methods of initiated polymerization of esters: block, water-based and in solvents.

The block polymerization method should be used for the production of polymethyl methacrylate, which is produced in the form of transparent and colorless plates and blocks (organic glass). Polymethyl methacrylate in the form of a block polymer is obtained by thoroughly mixing the initiator - benzoyl peroxide - with the monomer and then pouring the mixture into glass molds. The main difficulty of the block polymerization process lies in the difficulty of adjusting the temperature inside the block. Due to the exothermicity of polymerization and the low thermal conductivity of the polymer (0.17 W/m-°C), overheating inside the block is inevitable due to an increase in the reaction rate and, consequently, a sharp increase in temperature. This leads to the evaporation of the monomer, the formation of blisters, if the outer layers of the block are already sufficiently viscous and prevent the release of gases from it. Blisters can be avoided to a certain extent by changing the concentration of the initiator and the polymerization temperature. The thicker the resulting block, the lower the concentration of the initiator, the slower the rise in temperature and the lower the polymerization temperature. It must be borne in mind that local overheating, which is completely impossible to avoid, inevitably leads to internal stresses in the block due to the different degree of polymerization in its inner and outer layers.

The production process of organic glass includes the preparation of molds and their filling, preliminary and final polymerization and parting of molds. Molds are usually made of polished, mirror-like silicate glass, which must be thoroughly washed under dust-free conditions. To make the mold, take two glass sheets. On the edges of one of them, gaskets made of a flexible elastic material are placed, equal in height to the thickness of the block being produced. These gaskets are covered with a second sheet of glass, after which the edges are glued with strong and thin paper, leaving a hole for pouring the monomer. At the same time, the mixture is prepared by thoroughly mixing the monomer, initiator and plasticizer. Mixing can be done in a nickel kettle equipped with a propeller or anchor stirrer, hermetically sealed with a spherical lid, on which there is a hatch and fittings for loading the monomer, initiator and other components. Stirring is carried out at normal temperature for 30-60 minutes, after which the mixture enters the weight measuring cups through the lower drain fitting, and from the measuring cups through the funnel into the molds. Polymerization is carried out by sequentially passing through a number of chambers filled with molds with approximately the following regime: in the first chamber at 45--55 ° C they are 4--6 hours, in the second at 60-66 ° C - 8-10 hours and in the third at 85--125°C -8 hours. After polymerization, the molds are immersed in water, after which the blocks can be easily separated from the silicate glasses. Finished sheets are sent for cutting edges and polishing. Sheets should be transparent, without bubbles, swelling. Dimensions (with tolerances) and physical and mechanical properties must comply with the specifications. Polymethyl methacrylate glasses are produced in various thicknesses - from 0.5 to 50 mm and sometimes more.

Water-emulsion polymerization of acrylates is used to obtain casting and molding powders, as well as resistant water dispersions such as latex. Water and acrylic ether are taken in a ratio of 2: 1. If a rigid elastic material is required, then it is rational to use the "bead" method of suspension polymerization, obtaining a granular polymer. The initiator is benzoyl peroxide, which is dissolved in the monomer (from 0.5 to 1%). Magnesium carbonate is used as an emulsifier, as well as polyacrylic acid, polyvinyl alcohol and other water-soluble polymers. The size of the granules depends on the concentration of the emulsifier and the mixing speed. Water and monomer are taken in ratios of 2:1 or 3:1. The production process of granulated polymer consists of loading raw materials into the reactor, polymerization, filtration and washing of polymer granules, drying and screening.

Distilled water and monomer are sequentially loaded from a mernik into a nickel reactor equipped with a steam jacket and a stirrer, then an emulsifier is added manually through a fitting. After stirring for 10--20 min, a plasticizer, a dye and an initiator soluble in the monomer are introduced into the reactor. By supplying steam to the reactor jacket, the temperature is raised to 70–75°C. After 40--60 min due to the heat released as a result of polymerization, the temperature in the reactor rises to 80--85°C. The temperature can be controlled by supplying water or steam to the reactor jacket. The control of the process is the determination of the content of the monomer. Polymerization continues for 2--4 hours; at the end of the polymerization, the reaction mixture is transferred to a centrifuge with a stainless steel basket, in which the polymer granules are easily separated and washed many times with water to remove the emulsifier.

The washed powder is loaded onto aluminum trays in a thin layer and dried in heating cabinets with a slow rise in temperature within 40–70 ° C for 8–12 hours. After drying, the powder is sieved and placed in a container. Granular polymethyl methacrylate without processing can be used for the manufacture of varnishes.

To obtain pressing powders, the granulated polymer must be passed through rollers for 3–5 min at 170–190°C; during this operation, plasticizers and dyes can be added to the polymethyl methacrylate. The rolled sheets are crushed in an impact-cross mill and sifted through a sieve.

ACRYLIC, a type of plastic (from the group of synthetic derivatives of one of the unsaturated ORGANIC ACIDS) with a short chain. By changing the reagents and molding methods, it is possible to obtain a product that is either solid and transparent, or soft and elastic, or liquid. Scientific and technical encyclopedic dictionary

acrylic- n., number of synonyms: 1 material (306) ASIS Synonym Dictionary. V.N. Trishin. 2013 ... Synonym dictionary

acrylic- - resin basis of car enamel - on a synthetic polyurethane and acrylate base - car enamels on this basis are two-component (2K) dyes, because dry due to the polymerization of the resin as a result of a chemical reaction with a hardener, ... ... Automobile dictionary

Acrylic- m. 1. A kind of synthetic fiber. 2. A fabric made from such a fiber. 3. unfold products made from this fabric. Explanatory Dictionary of Ephraim. T. F. Efremova. 2000... Modern explanatory dictionary of the Russian language Efremova

acrylic- acrylic, but ... Russian spelling dictionary

Acrylic- synthetic fiber of high quality, warm, dimensionally stable, with protection against moths. (Encyclopedia of fashion. Andreeva R., 1997) ... Encyclopedia of fashion and clothing

acrylic- car resin car enamel base on synthetic polyurethane and acrylate base car enamels on this basis are two-component (2K) dyes, because dry due to the polymerization of the resin as a result of a chemical reaction with a hardener, ... ... Universal additional practical explanatory dictionary by I. Mostitsky

acrylic- y, h. Synthetic fiber, prepared with polyacrylonitrile or other similar ... Ukrainian glossy dictionary

acrylic- a; m. 1. Razg. The name of a group of synthetic polymers and materials from them. // Fiber, yarn from such a fiber. 100% a. // About products made from such yarn. Acrylic jumper. Wear a. ◁ Acrylic, oh, oh. Oh, the fabric. And those colors... encyclopedic Dictionary

acrylic- a; m. see also. acrylic 1) a) open. The name of a group of synthetic polymers and materials from them. b) resp. Fiber, yarn from such a fiber. 100% acr/l. this T. About products from such yarn. Acrylic jumper. Wear Acry/L… Dictionary of many expressions

Books

• Acrylic for beginners. How to search for a plot, create a composition, work with color and much more, Dietmar Stiller. Acrylic is a great material for beginners, and Dietmar Stiller's method is great for quickly mastering painting skills. For two weeks, draw with a poetic book every day - you ... Buy for 551 rubles
• Dark green acrylic (71-MAKR RLM64) , . Acrylic paint for models. It is recommended to dilute with "Master Acrylic" solvent. Composition: acrylic dispersion, mixture of pigments and additives. When used correctly, it is not dangerous. Way…

Polyacrylates are polymers and copolymers of acrylic and methacrylic acids and their derivatives.

As film-forming copolymers of acrylic monomers with various unsaturated compounds are used.

Monomers:

acrylic acid

methacrylic acid

and their derivatives of the general formula

Including esters, amides, nitriles, for example:

methyl methacrylate

butyl methacrylate

acrylamide

acrylonitrile

Esters of methacrylic (acrylic) acid are also used, in the alkyl substituent R¢ of which there are functional groups (hydroxyl, epoxy): glycol monoacrylic ethers, acrylic acid glycidyl esters, for example:

hydroxyethyl acrylate

glycidyl methacrylate

Of the monomers of other types, styrene is more often used in the synthesis of polyacrylates:

and vinyl-n-butyl ether:

Schematically, a polyacrylic copolymer can be represented by the following formula:

The units of acrylic acid derivatives in the composition of the copolymer give the film elasticity, and this effect is enhanced with an increase in the length of the alkyl radical.

Derivatives of methacrylic acid give the copolymer hardness and rigidity. As the length of R increases from C1 to C14 and its branching, the alkyl acrylate is converted into a plasticizing comonomer.

Non-acrylic components also change the properties of the film former over a wide range. So, styrene gives it rigidity, vinyl butyl ether - elasticity. By selecting the components and adjusting their ratio, it is possible to obtain copolymers that meet various requirements.

Polyacrylates used as film-forming materials are usually divided into two groups - thermoplastic and thermosetting.

Thermoplastic polyacrylates are products of copolymerization of monomers that do not contain other functional groups, except for double bonds. These are copolymers of methyl methacrylate with methyl - and butyl acrylate, butyl methacrylate, etc. The formation of coatings based on thermoplastic polyacrylates is not accompanied by chemical transformations and proceeds quickly at room temperature, but the resulting varnish coatings soften at elevated temperatures.

Thermoset polyacrylates are obtained by copolymerization of two or more comonomers, at least one of which, in addition to the double bond, has some kind of functional group. The curing of such materials occurs as a result of chemical transformations in which this functional group is involved, for example, with the introduction of hardeners.

According to the type of such functional groups, thermosetting polyacrylates are divided into:

1. with N-methylol groups;
2. with epoxy groups;
3. with hydroxyl groups;
4. with carboxyl groups.

Polyacrylates with N-methylol groups are prepared using acryl or methacrylamide as comonomer. This is how, for example, copolymers of these amides with butyl methacrylate, acrylonitrile, styrene, etc. are obtained.

Upon subsequent treatment of the copolymers with formaldehyde, N-methylol derivatives of amides are formed. To increase the stability of these copolymers, some of them are esterified with n-butyl alcohol. Schematically, the formation of polyacrylates with N-methylol groups and their esterified derivatives can be represented as follows:

Here M is a comonomer.

Methylolated copolymers of acryl - and methacrylamide at 160-170°C can be cured by conventional condensation reactions of N-methylol derivatives or their esters. For curing these polymers, hardeners can also be used - phenol-, urea-, melamine-formaldehyde and epoxy oligomers, polyisocyanates and hexamethoxymethylmelamine.

The mass fraction of amide units in the copolymer should not exceed 30%, otherwise the brittleness of the coatings increases sharply.

Polyacrylates with epoxy groups are obtained by polymerization of a mixture of monomers, one of which contains an epoxy group (glycidyl acrylate, glycidyl methacrylate). These copolymers cure with all common epoxy oligomer hardeners. But their use is limited by the scarcity of glycidyl ethers.

The composition of hydroxyl-containing polyacrylates includes hydroxyethyl or hydroxypropyl methacrylates. They are cured with polyisocyanates, as well as melamine- and urea-formaldehyde oligomers.

Carboxyl-containing copolymers are obtained by introducing into the composition of the acrylic copolymer from 3 to 25% monobasic unsaturated carboxylic acids, such as acrylic or methacrylic. Dibasic unsaturated acids or their anhydrides (for example, maleic) are also used. Copolymers containing up to 5% unsaturated acids are sometimes used as thermoplastics. A small amount of polar carboxyl groups gives coatings based on them increased adhesion.

Coatings based on acrylic series copolymers are optically transparent, with high gloss, chemical resistance, aging resistance. Coatings based on thermoplastic polyacrylates have high weather and light resistance. They are colorless, well sanded and polished, retain their luster for a long time.

Thermosetting polyacrylates form films with high mechanical strength, which is maintained at elevated temperatures, high water and atmospheric, benzo and chemical resistance, high adhesion to metals, as well as good decorative properties.

Coatings based on polyacrylates with methylol groups are characterized by particularly high adhesion to various metals and primers, very high mechanical strength and high water resistance. Polyacrylates with epoxy groups have exceptional anti-corrosion properties.

On the basis of polyacrylates, various paints and varnishes are obtained:

• solutions in organic solvents (varnishes);
• non-aqueous dispersions;
• aqueous dispersions;
• water soluble systems;
• powder materials.

Both thermoplastic and thermosetting polyacrylates are used as a film-forming agent in the manufacture of varnishes. Solvents: esters, ketones, aromatic hydrocarbons. Polyacrylates for varnishes are obtained by polymerization of monomers in suspension or in a solvent. The solutions are directly used in the form of varnishes.

Varnishes based on polyacrylates are used in the automotive industry, for painting rolled metal, aluminum building structures, as well as household appliances (washing machines, refrigerators).

Non-aqueous dispersions polyacrylates with a particle size of 0.1-30 μm can be obtained, for example, by copolymerization of acrylic monomers with a stabilizer in volatile organic solvents that do not dissolve copolymers (aliphatic hydrocarbons). Acrylic monomers with substituents having a high affinity with the liquid acting as the reaction medium, such as lauryl methacrylate, are used as stabilizers.

Main scope aqueous dispersions acrylates - automotive industry. They are also used to obtain high-quality coatings with good adhesion to various substrates - fabric, paper, wood, concrete, brick, etc. In addition, they are used in building paints (due to low penetration into the substrate and high thixotropy).

Water dispersions(latexes) are obtained by emulsion polymerization in the presence of water-soluble initiators and surfactants (emulsifiers). Based on them, emulsion paints are produced for the protection of products made of ferrous and non-ferrous metals and for exterior and interior decoration.

Water-soluble polyacrylates
synthesized by copolymerization of several monomers, of which at least two have different polar reactive groups, providing the solubility of the polymer in water and its curing on the substrate.

They are received:

1. copolymerization of acrylic monomers in water-miscible organic solvents;
2. emulsion copolymerization with subsequent transfer of the latex into an aqueous solution by neutralization of the carboxyl groups of the copolymer with amines.

Water-soluble polyacrylates are used to obtain paints and varnishes applied by electrophoresis. The resulting films have better adhesion to the substrate than polyacrylate coatings applied by other methods.

To receive powder materials only thermoset polyacrylates with carboxyl, hydroxyl and epoxy groups are used. In powder materials, copolymers are used in combination with hardeners. Polyacrylate powder materials are applied by electrostatic spraying and are used for painting car bodies, household electrical appliances, etc.

On fig. 57 is a diagram of the production of an acrylic copolymer by an emulsion process.

In the reactor 6, equipped with a steam-water jacket, an aqueous phase is prepared, consisting of water heated to 50 ° C and an emulsifier, and with vigorous stirring, a mixture of monomers purified from the inhibitor and a previously prepared solution of a water-soluble initiator (for example, ammonium persulfate) are charged. The copolymerization is carried out in a stream of nitrogen at 75-80°C. Upon completion of the synthesis, the copolymer emulsion with continuous stirring is transferred to apparatus 9, which contains a 10% sodium chloride solution heated to 60-70°C; in this case, the destruction of the copolymer emulsion occurs. Then the reaction mixture, pre-cooled to 30°C, is fed to a horizontal washing centrifuge 10 with a screw discharge of the sediment, in which the polymer is squeezed out of the aqueous phase and washed with water. Drying of the squeezed and washed polymer is carried out in a fluidized bed dryer 12, after which the finished copolymer is sent to packaging through a receiving hopper 13.

Rice. 57. Technological scheme of the production process of polyacrylate by emulsion method:

1, 2, 7 - weight measurements; 3 - volumetric measure; 4, 8 - capacitors; 5 – liquid counter; 6, 9 - reactors; 10 – washing centrifuge; 11 - auger;

12 - "fluidized bed" dryer; 13 - receiving hopper

The scheme for the production of an acrylic copolymer in a solvent is shown in fig. 58.

Synthesis of the copolymer according to this scheme is carried out in the reactor 10, equipped with a jacket for heating with water vapor. A solvent is loaded into it (through a liquid counter 6) and a preliminarily prepared mixture of monomers containing the required amount of a solvent-soluble initiator is loaded from a weighing measuring device 5. A mixture of monomers with the addition of an initiator is prepared in apparatus 7, into which all the necessary components are fed from weight measuring devices 1 and 2 and volume measuring device 3. Copolymerization is carried out at 60–90°C (depending on the type of initial monomers and initiator) in an inert gas flow. The resulting copolymer solution (lacquer) is poured into an intermediate container 11, from where it is first sent for purification by filtration, and then for packaging.

Rice. 58. Technological scheme of the production process of polyacrylate in a solvent:

1, 2, 5 – weight measures; 3 - volumetric measure; 4, 8 - capacitors; 6 - liquid counter; 7 - mixer; 9 - centrifugal pump; 10 - reactor; 11-intermediate capacity; 12, 14 - gear pumps; 13 - plate filter

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Acrylic is the colloquial name for polymer, polymeric materials based on acrylic acid derivatives. Acrylic is a material of absolute transparency and purity, which has excellent physical and technical characteristics:

• has a low specific gravity, given the good strength;
• not afraid of the effects of temperature;
• quite resistant to ultraviolet;
• excellent mechanical characteristics.

Acrylic lacquer is a liquid ready for use, its composition is homogeneous, as a rule, milky in color. Acrylic lacquer is based on high-quality aqueous dispersions of resins, to which ennobling substances have been added. Acrylic lacquer is used to make decorative finishes to protect the surface of wood or wood-based materials or painted surfaces from various influences. At the same time, the technique of production work does not change. The main advantage of acrylic varnishes is that they dry quickly. They can be diluted with water and applied in liquid and pasty form, moreover, they do not crack, but create a smooth, shiny film. You can wash it off after drying, but only with a special solvent. Lacquer is applied to any non-greasy surfaces. It also gives transparent, high-strength, elastic coatings. It does not change the color of the substrate, and enhances the layered pattern of the wood. Moreover, the price of acrylic varnishes is not very high.

Acrylic varnish, which is made on the basis of alkyd-urethane resin, is used to treat wooden surfaces both indoors and outdoors. In addition, it is also used for covering parquet and wood floors, provided that the operating load is not high. After drying, the varnish forms a transparent hard film on the coated surface. This film is resistant to water, abrasion, etc.

Acrylic varnish is a chemical solution that is completely ready for use, is homogeneous in composition; it is produced in the form of a milky liquid. Based on high quality water dispersion. The lacquer contains acrylic resin. Lacquer is used for decorative finishing, as well as protection of wooden surfaces.

Varnish is used to process paper, wallpaper, cardboard, various plaster materials, building structures, rolled metal, plastics, vinyl, fiberboard, glass fiber, drywall, brick and more. Acrylic varnish dries quickly enough and is absolutely harmless to the environment. In addition, this type of paint and varnish products is highly resistant to detergents, moisture, temperature fluctuations, and ultraviolet rays.

Acrylic lacquerandits benefits.

Among the advantages of varnish are incombustibility, excellent decorative and aesthetic properties, elasticity and strength, good adhesion. Acrylic varnish has recently been used, but in this short time it has become a fairly popular product in the construction market. It perfectly mixes up with water, ether, alcohol, practically has no smell. Suitable for both interior and exterior decorating.

Lacquer is applied in liquid or pasty form on a previously cleaned dry surface with a brush, roller or spray. The process is easy enough. Before choosing an acrylic varnish, study the surface you want to treat well. If it is uneven, you should choose a matte option. For smooth walls, choose glossy.

Acrylic lacquer

andapplication features.

An important step is preparing the surface for processing. Before work, the surface is well cycled, dried, polished, and also cleaned of dust, grease and various kinds of contaminants.

If the surface has previously been treated with varnish, then it will be necessary to grind and clean until a matte state is achieved. After that, dust residues are removed, control varnishing is performed.

Before applying the varnish is thoroughly stirred. If the wooden surface is treated with varnish for the first time, then it is first coated with 10 percent diluted white spirit varnish. After that, two layers of undiluted varnish are applied.

If before that the surface was varnished, then if the old and new coatings are compatible, it is suggested to cover the surface with two layers of undiluted varnish. Prior to this, wooden surfaces are primed.

Tips that will come in handy when using varnish.

If necessary, sanding is carried out between the layers. Do not forget that varnishing is carried out only at temperatures above + 5 ° C, and the temperature of the varnish should not be less than + 15 ° C. If you want to achieve the best result, then during the application and drying of the varnish, protect the surface from drafts, as well as direct sunlight.

Remember that before applying the varnish must be mixed well. By mixing the varnish, you can evenly distribute the additive that has sunk to the bottom and get a uniform composition that will be ideal for coating.

The mixing time of the varnish will depend on the volume of the container. To apply the paintwork material to the surface, it is necessary to use applicators for varnishes or special brushes. At the end of the work, the tools are wiped.

The condition of the surface will affect the consumption of varnish. Finally, the varnish will dry only after seven days. Then you can already bring in furniture and lay carpets.

However, if the temperature drops to +10 degrees, then the drying time will double.

Acrylic lacquer, water-dispersion, glossy, latex-based, resistant to UV radiation, moisture and detergents. Acrylic lacquer is used for decorative finishing and protection of wooden, wood-fibre, chipboard, mineral, stone, and painted surfaces, outside and inside buildings. PACKING (euro-bucket): 1 kg, 3 kg, 5 kg, 10 kg, 20 kg. Acrylic varnish is intended for decorative finishing and protection of wooden (except floors), as well as wood-like, mineral (plastered, concrete, brick), painted surfaces, outside and inside buildings.