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1. Acrylic polymers and copolymers and their preparation

This type of film-forming substances includes oligomers, polymers and copolymers of acrylic, methacrylic acids and their derivatives: esters, amides, nitriles, etc. Depending on the monomers and comonomers used, thermoplastic or thermosetting polymers with various physical properties can be obtained.

The raw materials for the production of acrylic polymers and copolymers are various monomers. Acrylic monomers can be polymerized various methods. The lacquer method is most suitable for making varnishes; The emulsion polymerization method is used to produce latex.

In the emulsion polymerization of acrylic monomers, water-soluble peroxides (ammonium peroxide, hydrogen peroxide, etc.) serve as initiators. Distilled water and monomer in a ratio of about 1:3, an emulsifier (about 3% by weight of the monomer) and an initiator (about 0.5%) are loaded into the reactor. Salts of high-molecular fatty acids (oleic), salts of organic sulfonic acids and other surfactants are used as emulsifiers. The reaction is carried out in a neutral or slightly acidic environment. The polymerization process takes place at 60–90 °C for 2–4 hours. The end of the process is determined by the content of residual monomer in the polymer, which should not exceed 1–2%. The resulting latex can serve as a semi-finished product for the production of adhesives, water-based paints and other compositions.

If it is necessary to isolate the polymer from the emulsion, sulfuric acid is added to the latex and the water is distilled off. In this case, the emulsion is destroyed, and the polymer precipitates in the form of a dispersed powder. The precipitated polymer is filtered and washed from the emulsifier with water or alcohol and dried at 40-70 °C.

When varnish polymerization of acrylic monomers, benzene, isopropylbenzene, chlorobenzene, toluene, cyclohexanone, etc. are used as solvents. Organic peroxides and dinitrile azobis(isobutyric) acid are used as initiators. The polymerization process is carried out at temperatures of about 70 °C. The end of polymerization is determined by the monomer content in the polymer, which should not exceed 2%. If the process of producing a polymer is carried out in a solvent that does not dissolve the polymer, then the latter precipitates in the form of a fine powder, which is then cleaned and dried.

When varnish polymerization of acrylic monomers, benzene, isopropylbenzene, chlorobenzene, toluene, cyclohexanone, etc. are used as solvents. Organic peroxides and dinitrile azobis(isobutyric) acid are used as initiators. The polymerization process is carried out at temperatures of about 70 °C. The end of polymerization is determined by the monomer content in the polymer, which should not exceed 2%. If the process of producing a polymer is carried out in a solvent that does not dissolve the polymer, then the latter precipitates in the form of a fine powder, which is then cleaned and dried.

1.1 General properties

Polymers can be solid, soluble in organic solvents or water, or in the form of emulsions or dispersions.

Polyacrylates, compared to other film-forming substances for paints, have a number of advantages:

1) resistance to chemicals;

2) colorlessness, transparency, resistance to yellowing even with prolonged exposure to unfavorable temperatures;

3) resistance to absorption of radiation with a wavelength above 300 nm (UV spectrum, if the polyacrylates do not contain styrene or similar aromatic compounds);

4) absence of double bonds;

5) ability to maintain gloss;

6) the stability of acrylates and especially methacrylates to hydrolysis.

It is believed that the presence of the listed properties in coatings is due to the properties of the individual monomers from which the polymer is obtained. Methyl methacrylate contributes to increased weather resistance, light fastness, hardness and gloss retention over a long period. Styrene increases strength and resistance to water, chemicals, salt fog, but reduces light fastness and gloss retention. Alkylated acrylates and methacrylates give the coating flexibility and hydrophobicity, while acrylic and methacrylic acids improve adhesion to metals.

In light of the fact that the defense environment is becoming more and more relevant, new requirements began to be applied to paint resins, which significantly expanded the range of paint and varnish systems. Modern varnishes and paints must contain little or no solvent (powder coatings), be diluted with water (waterborne paints), and be thermoplastic or reactive. All these properties must be obtained due to the polymer structure of film-forming substances. The most important technical parameters of the polymer are described below.

The glass transition temperature (T) affects adhesion, brittleness and peeling from the substrate, crack formation and resistance to high impact forces. It is relatively easy to adjust T in acrylates, for example, by changing the ratio of methylated methacrylate (Tg homopolymer - 105 °C) to n-butyl acrylate (Tg homopolymer - 54 °C). T also affects the properties of dispersions and the viscosity of solutions. At high T values, the drying time increases. At low molecular weights (< 6000), что весьма важно особенно для красок с высоким содержанием сухого остатка, температура стеклования зависит от молекулярной массы. Последующее структурообразование приводит к повышению температуры стеклования, который не зависит от плотности образования поперечных межмолекулярных связей.

The presence of styrene in film-forming substances reduces the resistance to UV irradiation and atmospheric influences, but at the same time increases resistance to chemical influences active substances, improves adhesion and wettability of the pigment. Therefore, manufacturers try not to use styrene in paints that are used as a top layer for exterior painting and to obtain transparent coatings.

The development of low solvent (high solids) paints is directly related to the use of polymers that have very low viscosity. For such film-forming substances, the fundamentally important parameters that determine viscosity are molecular weight and molecular weight distribution (MWD). To produce paints with a high solids content, oligomers with a molecular weight of about 1000-3000 are required. An acrylate film-forming agent with a molecular weight of 100,000 can be used to produce paint with a solids content of about 12.5% ​​and with a low viscosity sufficient for its application. A film-forming substance with a molecular weight of about 6000 makes it possible to obtain paint with a dry residue content of 50%. To obtain low viscosity, a minimum MWD is sufficient. However, with increasing molecular weight, the physical and mechanical properties of the paint improve. Therefore, low molecular weight film-forming agents that cross-link after application are used to produce low solids paints. The original paint consists of low molecular weight oligomers, and durable polymer films formed after cross-linking and during the drying process. Further possibilities for reducing viscosity are associated with specific interactions between the molecules of the film-forming substance and with the choice of a low-viscosity solvent that practically does not interact with the polymer. For powder coatings Melt viscosity is especially important. In this regard, acrylic polymers are at a disadvantage compared to polyesters.

For the industrial production of dispersions, it is necessary to introduce functional groups into the polymer chain. Most water-dispersion systems are polymers with free carboxyl groups. The ability to dilute with water is achieved by neutralizing acid groups with aqueous alkali or amines. Film-forming agents may also contain nitrogen groups. Subsequent formation of the dispersion can occur after neutralization (for example, acetic or lactic acid). Since the viscosity of dispersions depends very little on molecular weight, polymers with very high molecular weights are usually used. Therefore, dispersions are ideal for producing physically drying coatings. Structure formation occurs due to the introduction of functional groups.

When used without aqueous dispersions Solvent release from paints can be reduced without reducing molecular weight. Acrylates have been described above as film-forming agents for anhydrous dispersions, but in addition to low viscosity they have several other advantages over conventional coatings and, moreover, should compete with high solids paints and powder coatings.

1.2 Structure formation of polyacrylates

Unlike thermoplastic polymers, structured polymers are insoluble, have higher hardness and are resistant to chemicals. These properties are extremely important for the production of high-quality coatings. Structure-forming reactions gained importance in the 1950s with the introduction of acrylic resins into the automotive industry.

The next impulse and area for the creation of paints and varnishes was associated with the tightening of environmental legislation. The emergence of requirements to reduce the solvent content of paints and replace traditional solvent paints with medium and high solids paints meant that the molecular weight of film-forming substances could be reduced to such a level that it was impossible to maintain the required properties of paints (for example, obtaining coatings with optimal film formation , hardness and elasticity). These properties can be obtained by increasing the molecular weight as a result of structure formation after coating. The chemical reaction after application also benefits high molecular weight dispersions. They increase the glass transition temperature and film strength.

A widely used method for structuring paint films consists of a reaction between hydroxyl-containing acrylates and melamine-formaldehyde resins or urea-formaldehyde resins. Hydroxyl-containing acrylates are prepared using comonomers such as hydroxyethyl methacrylate or butanediol monoacrylate. Amino resins are self-structuring to some extent; they also form intermolecular bonds with acrylates through hydroxyl groups. Structure formation can occur during the curing process at a temperature of about 130 ° C, or in the presence of acid catalysts. These paints have remarkable gloss and weather resistance.

Another important structuring method is the interaction of hydroxyl-containing acrylates with polyisocyanates, which act as hardeners. This mixture is structured when room temperature and, therefore, must be manufactured and stored as a two-component system consisting of a base and a hardener. The reaction between aromatic isocyanates and hydroxyl-containing acrylates occurs very quickly. Since aliphatic isocyanates react much more slowly, the reaction is catalyzed by the addition of dibutyltin dilaurate, amines or acids. The properties of such polyurethane paints are superior to those of most others. paint and varnish materials, and their scope of application is constantly growing. There are also one-component polyurethane paints based on hydroxyl-containing acrylates. They use blocked isocyanates as a hardener. Such systems typically require relatively heat drying (more than 150 °C).

The third group of structure formation reactions affects acrylic resins containing free carboxylic acid groups. Polyepoxides are mainly used as structure-forming substances for the production of solvent-soluble paints or powder coatings. In terms of resistance to alkalis and solvents, such compounds are superior to others, for example, those cured with isocyanates or melamine-formaldehyde resins. To do this, they require a very high curing temperature (more than 200 ° C). The curing temperature can be reduced to 120-150 °C if tetrabutylammonium iodide or tertiary amines are used as a catalyst. However, the use of catalysts reduces storage stability to several weeks.

If less stringent requirements are imposed on chemical resistance, abrasion and strength (responsible for complete cross-linking), then carboxyl-containing acrylates can be cured using diamines or metal complexes. This method is widely used, especially in the preparation of aqueous dispersions. Structure formation has also been reported with bisoxazoline.

Aqueous acrylic dispersions are actively used in the production of wood coatings or anti-corrosion coatings. Such paints often do not require drying at elevated temperatures and their mechanical properties improve if structure formation occurs at room temperature. Aziridines or dihydrates are usually used as cross-linking agents, which are mixed with dispersions after the end of the production process.

There are many other structure-forming processes, but they have not been found wide application, or appeared only recently as results of scientific developments. The structure formation of oxide-containing acrylates with amino resins and reactions with polysulfonazides are reported.

An alternative to curing paints is the production of self-crosslinking acrylic polymers, which react with each other at low temperatures without the addition of external structurants. Such coatings are used due to their chemical resistance, strength and elasticity, but they are less varied in composition and can cause problems due to their instability during storage. In addition, to achieve a high degree of structuring, it is necessary that the minimum molecular weight be higher than that of resins that are not self-structuring. Accordingly, when using such systems it is impossible to obtain paints with a high solids content.

1.3 Applications

Acrylic paints and varnishes are used in a variety of applications and are applied using all commonly used methods. Recent research into low-solvent paints and aqueous dispersions has shown that there is a need for new special formulations.

Description of work

This type of film-forming substances includes oligomers, polymers and copolymers of acrylic, methacrylic acids and their derivatives: esters, amides, nitriles, etc. Depending on the monomers and comonomers used, thermoplastic or thermosetting polymers with various physical properties can be obtained.
The raw materials for the production of acrylic polymers and copolymers are various monomers. Polymerization of acrylic monomers can be carried out using various methods. The lacquer method is most suitable for making varnishes; The emulsion polymerization method is used to produce latex.

Acrylic polymers are widely used due to their excellent properties such as transparency, strength, chemical resistance and weather resistance. These include polymers containing acrylic and methacrylic esters in their structure along with other vinyl unsaturated compounds. They can be either thermoplastic or thermosetting, and when producing the latter, the formulation includes monomers with additional functional groups that, after the formation of the initial polymer, are capable of further reactions with the formation of crosslinks. Great importance has copolymerization of vinyl and acrylic monomers, since in this case there are much great opportunities than with polycondensation, control the structure of the polymer and give it special properties. Various publications discuss quite fully the issues of obtaining and using acrylic polymers in coatings.

Depending on the properties that the monomers impart to the final polymer or copolymer, their. can be classified as "hard", "soft" or "reactive". Solid monomers, for example, are methyl methacrylate, styrene, vinylacet. Acrylates are “softer” than methacrylates; “soft” monomers include: ethyl acrylate, 2-ethylhexyl acrylate, and long-chain methacrylates. Reactive monomers may have hydroxyl groups, such as hydroxyethyl acrylate. Acrylamide and especially glycidyl methacrylate have sufficient reactivity. Acidic monomers are also reactive; Methacrylic acid is often added in small quantities since the acid groups can improve pigment dispersion and catalyze copolymer curing.

Methyl methacrylate as a solid monomer provides resistance to gasoline, UV irradiation, and ensures gloss retention. Therefore, it is used in copolymers for topcoats, especially in automotive refinishing. Butyl methacrylate, a softer monomer, imparts very good moisture resistance to cold-cured materials, but its plasticizing effect is limited. It imparts good intercoat adhesion, solvent resistance, excellent UV resistance and gloss retention. Ethyl acrylate has good plasticizing properties, but the monomer vapors are very toxic and have an unpleasant odor. Its copolymers are quite resistant to UV radiation and retain their shine well.

In practice, acrylic polymers for coatings are rarely homopolymers, but are copolymers of hard and soft monomers. The hardness of a polymer is characterized by its glass transition temperature (, and for a particular copolymer its Tg can be calculated using the equation l/TG = W(/TG + W-z/TG-i, etc., where TGi, TG-i are the temperatures TQ of the homopolymers of the constituent monomers in K, a Wi, W2 are their mass fractions. For thermosetting polymers, such a calculated Tg will not be the Tg of the final film, since crosslinking will lead to a further increase in Tg, and this must be kept in mind.

Although copolymerization can produce polymers of various structures (random, alternating, block or graft), statistical copolymers are used in the vast majority of cases for coatings. Their statistical nature also determines that the phenomena of tacticity and crystallization, so important for the bulk properties of polymers, in these polymers for coatings are practically not observed. And the most common structural effects in these polymers are phase separation and domain effects, which occur either by chance or are planned in advance.

The twentieth century became, without exaggeration, the century of plastic. The production of inexpensive and practical material flourished after World War II and has only gained momentum since then.

By 2015, the world produced over 320 billion tons of synthetic polymers (not counting fiber).

For a long time people didn't think about what would happen to plastic products after use. Attention to this problem began to be paid only in last years, reports The Conversation.

Let us remember that polymers are common name substances with long molecules (macromolecules) consisting of chains of monomers. The number of such “links” can be up to half a million. They have great strength and durability.

The most common thermoplastic, which can become viscous when heated and then harden again. new form. This process can be repeated many times.

One of the pioneers of the modern polymer industry was Wallace Carothers, who in the 1930s discovered a method for producing nylon and participated in the creation of neoprene. Nylon has become very popular in commercial activities - in particular, it has replaced rare and expensive silk in the production of stockings.

After World War II, in conditions of shortage of many materials, synthetic polymers became a real salvation. Thus, after the Japanese invasion of Southeast Asia, the supply of rubber for car tires, and its synthetic equivalent was created. Some materials, such as Teflon, were discovered by accident.

Nowadays, the production of synthetic polymers worldwide is dominated by polyolefins: polypropylene and high- and low-density polyethylene. They can be made using relatively inexpensive natural gas. Polyolefins are resistant to water, air, grease, and cleaning solvents. They are also the lightest synthetic polymers produced on a large scale: their density is so low that they do not sink in water.

But these materials also have serious disadvantages, which humanity did not immediately think about. Their great strength allows them not to decompose for decades, if not hundreds of years. Getting into sea water, they break up into microparticles and enter the stomach of fish, seabirds, turtles, seals and plankton, and then into the human body.

Experts estimate that an average serving of mussels may contain about 90 microplastic particles. sea ​​salt– up to 600 particles per kilogram, one shrimp – 5-7 particles.

At the same time, humanity is in no hurry to give up plastic. make up 35-45% of all polymer products. Construction Materials, such as PVC pipes- 20%. Polyurethanes are widely used for insulating coatings.

The automotive industry is using more and more thermoplastics, primarily to reduce vehicle weight.

According to EU experts, 16% of the weight of an average car is made up of plastic components, in particular, interior parts.

More than 70 million tons of thermoplastics per year are used in the textile industry, mainly in the manufacture of clothing and carpets. More than 90%, mainly polyethylene terephthalate, is produced in Asia.

Synthetic fibers eliminate cotton and wool, which require extensive agricultural land.

Like packaging materials, textile products poorly processed. Each person in the United States produces, on average, more than 90 pounds (about 40 kg) of textile waste per year.

According to Greenpeace, in 2016 people bought 60% more more items clothes annually than 15 years ago, and they stored less of it.

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

Copolymers of acrylic monomers with various unsaturated compounds are used as film-forming agents.

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, the alkyl substituent R¢ of which contains functional groups (hydroxyl, epoxy): monoacrylic ethers of glycols, glycidyl esters of acrylic acids, for example:

hydroxyethyl acrylate

glycidyl methacrylate

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

and vinyl-n-butyl ether:

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

Units of acrylic acid derivatives in the copolymer provide elasticity to the film, and this effect increases with increasing length of the alkyl radical.

Methacrylic acid derivatives 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. Thus, styrene gives it rigidity, vinyl butyl ether - elasticity. By selecting components and adjusting their ratio, it is possible to obtain copolymers that satisfy various requirements.

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

Thermoplastic polyacrylates are products of copolymerization of monomers that do not contain functional groups other than 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.

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

Based on the type of 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 obtained by using acrylic or methacrylamide as a comonomer. This is how, for example, copolymers of these amides are obtained with butyl methacrylate, acrylonitrile, styrene, etc.

Upon subsequent treatment of 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.

Methylated copolymers of acrylic and methacrylamide at 160-170°C can be cured by conventional condensation reactions of N-methylol derivatives or their esters. To cure 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 fragility of the coatings sharply increases.

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 are cured by all common epoxy oligomer hardeners. But their use is limited by the scarcity of glycidyl ethers.

Hydroxyl-containing polyacrylates include 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 acrylic copolymer composition from 3 to 25% monobasic unsaturated carboxylic acids, for example 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 copolymers are optically transparent, with high gloss, chemical resistance, resistance to aging. Coatings based on thermoplastic polyacrylates have high weather and light resistance. They are colorless, sand and polish well, and retain their shine for a long time.

Thermosetting polyacrylates form films with high mechanical strength that persists at elevated temperatures, high water, 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.

Various paints and varnishes are produced based on polyacrylates:

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

Both thermoplastic and thermosetting polyacrylates are used as film-forming agents in the manufacture of varnishes. Solvents: esters, ketones, aromatic hydrocarbons. Polyacrylates for varnishes are obtained by polymerizing 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, and household appliances (washing machines, refrigerators).

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

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

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

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

They are received by:

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

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

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

In Fig. 57 shows a diagram of the production of acrylic copolymer by the emulsion method.

In 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 pre-prepared solution of a water-soluble initiator (for example, ammonium persulfate) are loaded. 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 copolymer emulsion is destroyed. Then the reaction mixture, pre-cooled to 30°C, is fed to a horizontal washing centrifuge 10 with a screw discharge of sediment, in which the polymer is squeezed out from the aqueous phase and washed with water. Drying of the pressed and washed polymer is carried out in a “fluidized bed” dryer 12, after which the finished copolymer is sent through the receiving hopper 13 for packaging.

Rice. 57. Technology system process for producing polyacrylate using the emulsion method:

1, 2, 7 – weight measuring instruments; 3 – volumetric measuring cup; 4, 8 – capacitors; 5 – liquid meter; 6, 9 – reactors; 10 – washing centrifuge; 11 – auger;

12 – “fluidized bed” dryer; 13 – receiving hopper

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

The synthesis of the copolymer according to this scheme is carried out in reactor 10, equipped with a jacket for heating with water vapor. A solvent is loaded into it (via a liquid meter 6) and a pre-prepared mixture of monomers containing required amount organosoluble initiator. A mixture of monomers with the addition of an initiator is prepared in apparatus 7, into which all the necessary components are supplied from weight measuring cups 1 and 2 and volumetric measuring cup 3. Copolymerization is carried out at 60-90°C (depending on the type of initial monomers and initiator) in a flow of inert gas. The resulting copolymer solution (varnish) is poured into an intermediate container 11, from where it is first sent for purification by filtration and then for packaging.

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

1, 2, 5 – weight measuring instruments; 3 - volumetric measuring cup; 4, 8- capacitors; 6 - liquid meter; 7 – mixer; 9 - centrifugal pump; 10 - reactor; 11-intermediate capacity; 12, 14 – gear pumps; 13 - disc filter