WO2009116892A1 - Alkylketone fluorotelomers, methods for the production thereof (variants) and a method for producing functional coatings based thereon - Google Patents

Abstract

The invention relates to producing agents which are used for forming coatings which exhibit the properties intrinsic to polytetrafluoroethylen, i.e., resistance to chemical aggressive media, antifriction and water-repellent properties, in particular to fluor-contaning telomers and to methods for producing coatings based thereon. The inventive method for producing alkylketone fluorotelomers involves carrying out a free-radical telomerisation reaction of unsaturated perfluorolefins (for example tetrafluoroethylene TFE) in a telogen liquid medium with the ratio of TFE/telogen 0.5-20/100. In the preferred variant, the reaction is carried out with the ratio of TFE/telogen (0.7-3)/100 in such a way that a telomer colloidal solution is formed, which solution is used for applying heat-resistant highly-adhesive coatings the thickness of which ranges from 1 to 5 mkm.

Description

 Fluoromeres of Alkylketones, Methods for Their Preparation

(OPTIONS) AND METHOD FOR PRODUCING FUNCTIONAL

COATINGS ON THEIR BASIS

FIELD OF THE INVENTION

The invention relates to a method for producing substances used to obtain coatings having properties inherent in polytetrafluoroethylene, i.e. resistance to chemical aggressive environments, antifriction and water-repellent properties, namely, to fluorine-containing telomeres and methods for producing coatings based on them.

State of the art

Known telomeres of tetrafluoroethylene (TFE) and methods for their preparation using aliphatic acids, alcohols, aldehydes, esters, halogens, sulfones as telogens [http./www.ta2238/2007; DE 3219004, Cl, 1984; DE 3915759, Al, 1990; S. Kotov, G. Kostov, E. Balbolov. Re.t. Kipet. Catal. Lett., V. 63, 1 (1998) 107; I. Wlassiсs and V. Tortelli. Homel of Fluoripe Chemistru. V.127, Issue 2, February 2006, P.240]. Such telomeres are widely used as intermediates in the synthesis of fluorine-containing compounds, surfactants, and repellents.

The process is based on the telomerization of lower perfluoroolefins (e.g. TFE) with various telogens.

Typically, the telomerization process is initiated by radical initiators - chemical [http./www.ta2238/2007; DE 3219004, Cl, 1984; DE 3915759, Al, 1990; S. Kotov, G. Kostov, E. Balbolov. Re.t. Kipet. Catal. Lett., V. 63, 1 (1998) 107; I. Wlassiсs and V. Tortelli. Jourpael of Fluoripe Chemistru. V.127, Issue 2, February 2006, P.240] and ionizing radiation [US 3235611, Kl.260-653.1, 1966].

The work [http./www.ta2238/2007] provides the following data on various fluorotelomers:

1) Perfluorinated alcohols are of interest as building blocks for pharmaceuticals and agricultural chemistry. CF ₂ OH and CFOH groups are unstable and decompose into hydrogen fluorides and fluorinated carbonyl compounds to form stable adducts of perfluoroalcohols with amino groups (Cheburkovapd Lillquist, 2002) RFCF ₂ O HNEt ₃ ⁺ (RF: F, C ₂ F ₅ ; iC ₃ F ₇ ). 2) Fluorotelomers of sulfonates (FTS) F (CF ₂ ) _{6 - 0} SO ₃ ^" with amino groups (FTSA). There are no data on T _nl and vapor pressure.

3) Fluorotelomers of acids. F (CF ₂ ) _6- yuCH ₂ CH ₂ CO ₂ ^" . T _pl = 87.8 ⁰ C (8: 2) FTCA. T _pl = 106.6 ⁰ C (8: 2) FTUCA.

4) Alcohol fluorotelomers: F (CF ₂ ) _6-10 CH ₂ CH ₂ OH. T _pl no. Vapor pressure: 0.876 kPa (6: 2); 0.227 kPa (8: 2)

5) Fluorotelomers of aldehydes F (CF ₂ ) _6- хCH ₂ CH ₂ CHO. Oh no. Vapor pressure: 0.067 kPa (8: 2) FTAL

6) Telomeres of iodides and olefins FTiidid F (CF ₂ ) _OI oCH ₂ CH ₂ I; FTolefm F (CF ₂ ) ₆ - _I0 CH = CH ₂ T _11n = SO С

Fluoroalkanols of the general formula H (CF ₂ CF ₂ ) _n CH ₂ OH (n = l-4) are intermediates for the synthesis of certain chemical compounds and thermally stable fluorine-containing coatings, high-temperature lubricants and coolants, drugs, etc. Basically, the method of their preparation consists in the free-radical telomerization of TFE with methanol in the presence of initiators [DE 3219004, Cl, 1984; DE 3915759, Al, 1990]. In [S. Kotov, G. Kostov, E. Balbolov. Rept. Kipet. Catal. Lett., V.63, 1 (1998) 107], free-radical telomerization of TFE with methanol was carried out in the presence of azoisobutyronitrile (AIBN). TFE (0.5-2.0 g) was introduced into a 12 cm ³ steel ampoule with 5 cm ^{3 of} methanol and 0.05-0.06 g of AIBN. After removing traces of oxygen, the temperature of the contents of the ampoule was brought to room temperature, then the mixture was heated to 7O ⁰ C. After removal of unreacted TFE, the liquid mixture was analyzed on a gas chromatograph. Low-molecular-weight products H (CF ₂ CF ₂ ) _n CH ₂ OH with n = l-3: 1H, 1H, 3H-tetrafluoro-1-propanol (bp 109 ^° C), W, W, 5H-octactopro-l- were isolated pentanol (Tkip. 141 ⁰ C) and Ш, lH, 7H-dodekaftop-l-heptanol (Tkip. 170 ⁰ C). The remaining high molecular weight wax-like telomeres had the formula H (CF ₂ CF ₂ ) _n CH ₂ OH, where n> 3. The telomerization of C ₂ F ₄ (TFE or TFE) and bromochlorofluoroethanes was studied in [I. Wlassiсs and V. Togtelli. Homel of Fluoripe Chemistru. V.127, Issue 2, Februar 2006, P.240] depending on the type of initiator and telogen, TFE pressure and temperature. Peroxides initiate telomerization between dibromohaloethanes and C ₂ F ₄ , providing synthesis of the α, ω-dibromo of perfluoroalkanes Br (CF ₂ ) _n Bg, where n = 2,4,6,8. The choice of telogen and its ability to act as a “donor of bromine” in radical telomerization is important. These perfluoroalkyl dibromides are useful as intermediates for derivatives, for example, perfluorinated mono and diolefins Br (CF ₂ ) _n CH = CH ₂ and CH ₂ = CH (CF ₂ ) _n CH = CH ₂ .

No. 3,235,611 describes a process for the preparation of tetrafluoroethylene telomers by radical polymerization in the presence of telogens, chlorinated hydrocarbons. As initiators use x-ray or γ-rays or fast electrons. The result is telomeres with the general formula Cl ₂ C = CCl (C ₂ F ₄ ^ Cl, where 20>n> 2.

The telomerization process to obtain fluorinated telomeres of alkyl iodides, which consists in the telomerization of polyfluoroalkyl iodides with unsaturated polyfluoro olefins or monochlorofluor olefin, is described in [US 5908966, 1999]. The process consists in the contact of polyfluoroalkyl mono-iodide or di-iodide, linear or branched, containing chlorine and / or bromine, and / or essential oxygen in a chain, or a functional group, with an unsaturated perfluoroolefin or monochloroperfluoroolefin at a temperature of from about 300 ⁰ C to 400 ⁰ C, with a molar ratio of polyfluoroalkyl iodide to unsaturated olefins of about (1, 1-1.9): 1.

The creation of crosslinkable composites for protective optical fibers that improve optical, mechanical, adhesive and water repellent properties is described in [US 5690863, 1997]. Silicon optical fibers or plastic composites consist of two materials - a light-conducting core and a sheath. Usually, the greater the difference in the refractive indices of the core and the shell, the better the luminescent properties of the fibers. High fluorinated monofunctional acrylates or methacrylates of the general formula CH ₂ = C (R) COOCHXY, where R is H or methyl; X is CF ₃ or H, provided that if X is H, then Y will be (CH ₂ ) _n (CF ₂ ) _m Z; where Z is F or H; n = 0-4; m = l-10.

The closest to the described invention in terms of technical nature and the achieved result are tetrafluoroethylene telomeres and the method of their production by radical polymerization in the presence of telogens - aliphatic ketones or carboxylic acid amides, initiated by ⁶⁰ Co gamma radiation or chemical initiators [Copyright certificate SU 665747, published January 27, 2008 . B.I. JNbЗ].

In accordance with the method disclosed in SU 665747, short chain telomeres with an average chain length of not more than n _C p = 5.5 are obtained. Telomeres with a higher value of n (6 <n <20) according to the specified method are obtained only in a small amount, in particular, telomeres with a value of 10 <n <20 receive only in impurity quantities. Telomerization products, consisting mainly of short chain telomeres, have low thermal stability, because the boiling points of such short-chain compounds are usually lower than 200 ⁰ C, which does not allow to obtain durable coatings that are stable at high temperatures and limits the possibility of their use to create protective coatings.

Closest to the described invention in terms of the production of coatings is the method described in [D. D. Chegodaev et al. Fluoroplasts, L., Chemistry, 1960, p. 153-180] for the preparation of stabilized aqueous suspensions of ftoron-4D. Suspensions made from dispersions obtained during the polymerization are unstable and easily coagulate, and therefore, immediately after their preparation, surfactants are added to them. Then the product should be centrifuged. Further, to prepare a marketable suspension, water and a certain amount of surfactants are added to the concentrated precipitate. Therefore, the process of preparing such suspensions is time-consuming and multi-stage. After applying such emulsions to the surface to be protected, the coating is sintered at 350-380 ^° C to obtain a monolithic coating and the impurities of the emulsifier and stabilizer are burned out. With this technology, homogeneous coatings with a thickness of less than 20 microns cannot be obtained. In addition, the remnants of a pyrolyzed emulsifier contaminate the coating and impair its chemical resistance and electrical insulation characteristics. A continuous defect-free coating using suspensions can be obtained only by successively applying up to 10 layers according to the technology described above, and the minimum thickness of the applied layer can be at least 10 microns.

The specified method for producing coatings is multi-stage, requires a high heat treatment temperature, while the thickness of the resulting coating is at least 10 microns. This feature of suspensions narrows the scope of their use and practically limits their use as chemically resistant coatings of surfaces with complex configurations (for example, sand surfaces).

Summary of invention

The objective of the invention is to obtain new fluorotelomers of alkyl ketones, allowing you to create durable heat-resistant coatings of micron thickness on substrates of various nature and configuration, such as sand, wood, glass, fabrics, etc.

The problem is solved by the claimed invention, according to which the fluorotelomers of alkyl ketones of the general formula R ₁ (CF ₂ - CF ₂ ) _n R ₂ are claimed, where n is an integer, preferably from 1 to 20; Ri and R ₂ are fragments of an alkyl ketone molecule. In this case, the chain length of fluorotelomers can be adjusted by selecting the concentration of TFE in the reaction mixture, namely, by changing the ratio of TFE / telogen, which can vary between (0.5-20) / 100.

In addition, the problem is solved by the method of producing fluorotelomers of alkyl ketones by performing a free-radical telomerization reaction of unsaturated perfluoroolefins (e.g. tetrafluoroethylene) in a telogen liquid medium at a temperature that provides kinetic efficiency of the process in which the free-radical reaction is initiated by ionizing radiation, for example, gamma quanta of ⁶⁰ Co with a molar ratio of TFE / telogen = (0.5-20) / 100, followed by isolation of the target product from the reaction mixture by known methods.

The problem is also solved by the method of producing fluorotelomers of alkyl ketones by carrying out the free-radical telomerization reaction of unsaturated perfluoroolefins (for example, tetrafluoroethylene) in a telogen liquid medium in which the free-radical reaction is initiated by chemical initiators at the initiator decomposition temperature at a molar ratio of initiator / TFE / telogen = 0 5 / (0.5-20) / 100.

In addition, the problem is solved by the method of producing coatings based on alkyl ketone fluorotomers, including applying a polymer-containing component to the substrate, followed by drying and heat treatment, in which a chemically pure telomere solution is applied to the substrate of various nature, configuration and size, and heat treatment is carried out at a temperature of 180-200 ⁰ C to obtain a high-quality continuous coating.

Detailed Disclosure of Invention

The invention consists in the following.

“Telomerization process” means a chemical reaction during free radical initiation in which one or more polymerization-prone molecules bind to another molecule called tellen. As An example of a telomerization process, this application describes the reaction of ketones (telogen) with fluorinated olefins such as tetrafluoroethylene (TFE) CH ₃ CO CH ₃ + nCF ₂ = CF ₂ → R ₁ (CF ₂ = CF ₂ ) _n R ₂ where n is the integer a number, preferably from 1 to 20, and Ri and R ₂ are fragments of a ketone molecule that are formed during the free radical telomerization reaction. For example, if the ketone is acetone, then the Ri and R ₂ fragments are H, CH ₃ , COCH ₃ , CH ₂ COCH ₃ . If methyl ethyl ketone is used as a ketone, such fragments can be H, CH ₃ , CH ₂ CH ₃ , COCH ₃ , COCH ₂ CH ₃ , CH ₂ COCH ₂ CH ₃ , CH ₃ COCH ₂ CH ₂ .

The molar ratio of TFE / ketone is (0.5 - 20) / 100. The telomerization process is carried out in the liquid phase when TFE is dissolved in telogen. With radiation initiation, the process is carried out at room temperature [US 3235611, Cl. 260-653.1, 1966]. When using chemical initiators, at a decomposition temperature of the initiator in the range from 80 to 100 ⁰ C [DE. 3219004, 1984; DE. 3,915,759, 1990; S. Kotov, G. Kostov, E. Balbolov. Re.t. Kipet. Catal. Lett., V. 63, 1 (1998) 107; I. Wlassiсs and V. Tortelli. Homel of Fluoripe Chemistru. V.127, Issue 2, February 2006, P.240; Chemical Encyclopedic Dictionary, M., Soviet Encyclopedia, 1983, p. 562.]. Under these conditions, a complete conversion of TFE occurs.

Typically, the telomerization product is a mixture of polyfluoroalkyl ketones with a wide molecular weight distribution, and not an individual compound. The molecular weight distribution of the products depends on the concentration of TFE in the mixture of reagents. Measurements carried out using gel permeation chromatography (GPC) of telomerization products directly in the reaction mixture showed that at a ratio of TFE / ketone (0.5-0.7) / 100, low molecular weight telomeres with a chain length of n = 1-8 are formed, wherein the average chain length is n _C p <6. When the ratio of TFE / ketone (0.7-3) / l 00, telomeres with a chain length l <n <20 are predominantly formed, while the average chain length is n _C p = 6-15. With a TFE / ketone ratio of 3-20 / 100, telomeres with an average chain length of n _C p = 15-20 are formed, and with a TFE / ketone ratio of more than 20/100, telomeres with an average chain length of n _C p> 20 are formed.

Thus, with a change in the concentration of TFE in the reaction mixture with ketone during radical telomerization, the following are formed:

1) true transparent colorless telomere solution with medium length chains n _C p <6 with the ratio of TFE / ketone (0.5-0.7) / 100;

2) a colloidal, opalescent, viscous telomere solution with an average chain length of 6 <n _C p <15 at 0.7 / 100 <TFE / ketone <3.0 / l 00.

3) oriented phase, which is a thick jelly-like solution of telomeres with an average chain length of 15 <n _C p <20, at

0.3 / 100 <TFE / ketone <20 / l 00;

4) a thick gelled essentially polymer solution of telomeres with an average chain length n _C p> 20 at TFE / ketone> 20/100.

In the IR spectra of dried telomeres, intense bands are observed at 1211 and 1154 cm ^"1 , characteristic of the CF ₂ group, and bands in the region of 1734 cm ^{" 1} , characteristic of the = C = O groups. The fact that the intensity of these bands is sufficient for experimental observation indicates a significant number of end groups and may indirectly reflect the small length of CF ₂ -molecular chains. The terminal groups of the chains are fragments of the ketone molecule.

Thermogravimetric analysis of the dried telomere shows an intense mass loss at a temperature of 100-500 ⁰ C depending on the concentration of TFE in the initial reaction mixture. Intensive mass loss of low molecular weight telomeres with n <8 occurs at temperatures of 100-300 C, which is associated with evaporation in the boiling area. For telomeres with a chain length of n> 15, mass loss occurs at higher temperatures, more than 400 ⁰ C, which may be due to thermal destruction of the substance.

The study of layers obtained from solutions by atomic force microscopy (ACM) shows that the removal of solvent from colloidal solutions leads to the formation of coatings consisting of submicron particles.

Since, as shown by GPC data, the products obtained from a reagent solution with different initial TFE concentrations have different structures, it should be expected that the structure of the layers formed upon removal of acetone from these solutions is also different. When the proportion of long chains grows, the orientation of the oligomers in the solution occurs. With an average chain length of n _C p> 6 (i.e., with an increase in the initial concentration of TFE), aggregates are formed in the form of colloidal particles of submicron size with an increased density of the oligomer. With a further increase in the initial concentration of TFE, the obtained oligomers transfer to the oriented phase, similar to liquid crystalline transition of the ensemble of rods into the nematic phase.

Removal of the solvent from the above states leads to the formation of layers of various structures. The true solution, which is formed by telomeres with an average chain length n _C p <6, turns into a molecular crystal with a low melting point, not suitable for obtaining durable heat-resistant coatings. On the other hand, the oriented phase containing telomeres with an average chain length of 15 <n _C p <20, passes into a state with a tight packing, which has a high melting point and does not have sufficient adhesion. A solution containing telomeres with an average chain length n _C p> 20 is not very suitable for coatings, since it has poor adhesion to the surface to be coated, and with little mechanical impact, the coating can be removed. Colloidal particles in which the density of oligomers is higher than in the true solution, but lower than in the oriented phase telomere, are capable of creating coatings with high adhesion and heat resistance at the same time.

Using diathermogravimetric (DTG) analysis, it was shown that coatings obtained from a true solution of acetone fluorotelomer, when the average chain length n _C p <6, completely evaporate when heated to 200-250 ⁰ C. Coatings obtained from a fluorotelomer solution with an average chain length n _™ > 15 have the highest heat resistance (> 400 ⁰ C), but poor adhesion and are easily removed by mechanical action. The coatings obtained from solutions with an average chain length of 6 <n _C p <15 with heat resistance up to 400 ⁰ C and satisfactory adhesion turned out to be optimal.

With radiation initiation, the process is carried out at room temperature. When using chemical initiators, at a decomposition temperature of the initiator in the range from 80 to 100 ⁰ C. Under these conditions, a complete conversion of TFE occurs.

After removal of acetone, a white solid remains, from which protective coatings with properties close to PTFE can be created - antifriction, heat resistance, hydrophobicity.

The method allows to obtain thin protective coatings having properties similar to those for PTFE, because only solutions can produce thin coatings with a thickness of 1-5 microns, and as a result, expand scope of fluorine-containing coatings. The method consists in obtaining tetrafluoroethylene telomeres by radical polymerization in the presence of telogens, which are used as aliphatic ketones, followed by applying a fluorotelomer solution to the treated surface, drying to remove unreacted telogen and heat treatment of the dry residue at a temperature of 180-200 ⁰ C, as a result of which the telomere melts and low molecular weight fractions evaporate (n <5), and higher melting fractions with n> 6 remain.

In addition to expanding the scope of application, coating from a solution simplifies the technology for producing films, since the solution can be stored for almost unlimited time in a hermetically sealed container in the range of existence of the solvent’s liquid medium, and heat treatment after application is carried out at 180-200 ⁰ C instead of 350-380 ⁰ C. Due to the film thickness being 1-5 microns, time processing is insignificant, which is very important when applying films to materials sensitive to such temperatures, and when applying films in non-stationary conditions using portable heating means.

The invention is illustrated by the following examples:

Example 1

Reagent grade acetone in a sealed reaction vessel was degassed in a vacuum unit to remove air dissolved in it. After the introduction of TFE in such an amount that its molar ratio to acetone is 0.5 / 100, the reaction vessel was tightly closed. Irradiation with ⁶⁰ Co gamma rays was carried out at room temperature with an integral dose of 20 kGy. The conversion of TFE occurs completely; when the vessel is opened, unspent gaseous TFE is not released.

The reaction product is a clear, colorless solution. The molecular weight distribution determined by gel permeation chromatography showed that the degree of polymerization of TFE in such a solution was n _C p <4. The dry residue after removal of acetone is completely soluble in acetone again. In the IR spectra of telomerization products, after removal of acetone, intense absorption bands characterizing CF ₂ groups and fairly intense bands related to carbonyl groups are observed, which are comparable with the bands of CF ₂ groups, which indicates that TFE oligomeric chains.

Thermogravimetric analysis of the dried telomere shows that Psr≤

4, and intense mass loss occurs at a temperature of 150-200 ⁰ C, which is associated with evaporation in the boiling area of the substance.

Example 2

The process was carried out similarly to Example 1 with a molar ratio of TFE / acetone of 1/100.

The reaction product is a colloidal solution. The molecular weight distribution determined by gel permeation chromatography showed that the degree of polymerization of TFE in such a solution was n _C p = 8. The dry residue after removal of acetone was re-soluble in acetone. In the IR spectra of telomerization products, after removal of acetone, intense absorption bands characterizing CF ₂ groups and fairly intense bands related to carbonyl groups are observed, which are comparable with the bands of CF ₂ groups, which indicates that TFE oligomeric chains are formed.

Thermogravimetric analysis of the dried telomere shows an intense mass loss at a temperature of 150-300 C, which is associated with evaporation in the boiling area of the substance.

Example 3

The process was carried out similarly to Example 1 with a molar ratio of TFE / acetone 5/100. The conversion of TFE occurs completely; when the vessel is opened, unspent gaseous TFE is not released.

The reaction product is a colorless viscous gel-like opalescent solution. The molecular weight distribution determined by gel permeation chromatography showed that the average degree of polymerization of TFE in such a solution was n _C p = 15. The dry residue after removal of acetone is repeatedly practically insoluble in acetone - less than 10% goes into solution. In the IR spectra of telomerization products, after removal of acetone, intense absorption bands characterizing CF ₂ groups and fairly intense bands related to carbonyl groups are observed.

Thermogravimetric analysis shows intense mass loss mainly at a temperature> 400 ⁰ C, which may be due to thermal degradation substances.

Example 4

The process was carried out similarly to Example 1 with a molar ratio of TFE / acetone 10/100. The conversion of TFE occurs completely; when the vessel is opened, unspent gaseous TFE is not released.

The product is a thick gel in which it is impossible to conduct GPC measurements. DTG showed only thermal degradation at temperatures above 500 ⁰ C, as in PTFE.

Example 5

The process was carried out according to Example 2 with telogen methyl ethyl ketone brand XC. A product similar to that of Example 2 was obtained.

Example 6

A 1% solution of benzoyl peroxide (C _O H ₅ CO-O) ₂ in acetone (melting point with decomposition of 106-107 ⁰ C) in a glass ampoule was degassed in a vacuum unit to remove the air dissolved in it. After introducing into the ampoule the required amount of TFE at a molar ratio of TFE / acetone = 2/100, the ampoule was sealed and heated to 100 ⁰ C for 5 hours. After the process, a clear, colorless, viscous colloidal solution is formed. The polymer yield, determined gravimetrically, was about 70%.

In the IR spectra of telomerization products, after removal of acetone, intense absorption bands characterizing CF ₂ groups and bands related to carbonyl groups are observed.

Example 7

The process was carried out as in example 6 using a 2% solution of ditretbutyl peroxide (CH) ₃ COOC (CH) ₃ in acetone (decomposition temperature 80-130 ⁰ C) at a molar ratio of TFE / acetone = 2/100, at a temperature of 100 ⁰ C within 4 hours. A colorless viscous colloidal solution with a gravimetric polymer yield of about 60% was obtained.

In the IR spectra of telomerization products, after removal of acetone, intense absorption bands characterizing CF ₂ groups and bands related to carbonyl groups are observed.

Example 8

The process was carried out as in example 6 using a 1% solution of dicyclohexyl peroxydicarbonate C ₆ HnOCO-OO-OCOC ₆ Hn in acetone (temperature decomposition 65-70 ⁰ C) with a ratio of TFE / acetone = 2/100 at a temperature of 80 ⁰ C for 2 hours. A colorless viscous colloidal solution with a gravimetric polymer yield of about 60% was obtained.

In the IR spectra of telomerization products, after removal of acetone, intense absorption bands characterizing CF ₂ groups and bands related to carbonyl groups are observed.

Example 9

The process was carried out as in example 6 using a 1% solution of 2,2-Azo-bis-isobitonitrile (CH ₃ ) ₂ C (CN) N = N (CN) (CH ₃ ) ₂ in acetone (melting point with a decomposition of 105- 106 ⁰ C) at a molar ratio of TFE / acetone = 2/100 at a temperature of 100 ⁰ C for 1 hour. The result was a colorless viscous colloidal solution with a gravimetric polymer yield of -30

Example 10

River sand in an amount of 100 g was poured with approximately 50 ml of telomere solution prepared according to Example 2 and dried to constant weight at a temperature of 5O ⁰ C. The polymer weight gain in sand was 0.28% by weight, which in terms of the specific surface of the sand gives the thickness value coatings of several hundred nm. After heating the sand at a temperature of 180 ° for 10 minutes, the grains of sand float in water without being wetted.

4 ml of treated sand was placed in a P1P-41 glass porous filter with a diameter of 25 mm and 10 ml of distilled water was poured. The beginning of the flow of water was recorded after 15 seconds, the full flow was achieved after 300 seconds. On untreated sand, the beginning of the course was recorded after 1 second, the end after 75 seconds. On an empty filter, the beginning of the leak was recorded after 1 second, the end - after 30 seconds.

Thus, even such a low content of a fluorine-containing film on the sand surface gives it hydrophobic properties.

Example 11

The telomere prepared according to example 2 was applied to plates of steel 3 (carbon steel of ordinary quality GOST 16523-89). The data are shown in table 1, which compared the data with the coating of varnish F-42 (fluoride varnish, produced by the polymer factory of the Kirov-Chepetsk chemical plant).

The table shows that the solution of TFE telomere gives a more hydrophobic coating compared to varnish F-42.

Example 12

The telomere prepared according to example 2 was applied to plates of glass, wood and a flap of cotton fabric. The data of the contact angle are shown in table 2.

table 2

The table shows that the coating of TFE telomere gives a hydrophobic property to the treated surface.

Example 13

The telomere prepared according to Example 2 was applied onto nitrile rubber plates based on nitrile butadiene rubbers 1078 (CKH-18 + CKH-26) and B 14 (CKH-18) (manufactured by the Scientific Research Institute of the Rubber Industry (NIIRP)) and measured the coefficient of friction on a friction machine with a three-ball intendor, with a diameter of steel balls of 8 mm, the friction duration of 1 min The coating thickness was 10-15 μm. Data are given in table 3.

Table 3

The coating of telomeres leads to a decrease in the coefficient of friction by 10-20%.

Low molecular weight oligomers can be used as protective coatings having properties similar to those of polytetrafluoroethylene, such as antifriction, hydrophobicity.

Example 14

The telomere prepared according to examples 1, 2 and 4 was applied to a glass slide (2.5x7.5) cm ² and dried at room temperature to constant weight. A white coating formed. The coated slide was heated in an oven at 200 ^° C for 20 minutes. Comparative characteristics of the resulting coatings are shown in table 4.

Table 4

Из таблицы видно, что покрытия из теломера, приготовленного по примеру 1, тонкие и гидрофобные, но при прогреве происходят большие потери веса. Покрытия из теломера по примеру 2 термоустойчивы и гидрофобны. Покрытия из теломера по примеру 4 отслаиваются и не пригодны для создания однородных защитных покрытий.

The table shows that the coatings from the telomere prepared according to example 1 are thin and hydrophobic, but when heated, large weight losses occur. The telomere coatings of Example 2 are thermally stable and hydrophobic. The telomere coatings of Example 4 exfoliate and are not suitable for creating uniform protective coatings.

Claims

CLAIM 1. Fluorotelomers of alkyl ketones of the general formula Ri (CF ₂ = CF ₂ ) _n R ₂ where R ₁ and R ₂ are fragments of an alkyl ketone molecule, and n is an integer, mainly from 1 to 20 ;. 2. A mixture of fluorotelomers of alkyl ketones of the general formula R ₁ (CF ₂ = CF ₂ ) _n R ₂ where Ri and R ₂ are fragments of an alkyl ketone molecule, n is an integer, while the average chain length of fluorotelomers in the mixture n _C p is 6 <n _C p <15. 3. A method for producing fluorotelomers of alkyl ketones by carrying out the free radical telomerization reaction of unsaturated perfluoroolefins, in particular TFE tetrafluoroethylene, in a telogen liquid medium, which is used as an alkyl ketone, at a temperature that provides kinetic efficiency of the process, characterized in that the free radical reaction is initiated by an ionizing radiation, for example, with ⁶⁰ Co gamma rays, with a molar ratio of TFE / telogen = (0.5-20) / 100. 4. The method according to p. 2, characterized in that the molar ratio of TFE / telogen is (0.7-3.0) / 100. 5. A method for producing fluorotelomers of alkyl ketones by carrying out the free radical telomerization reaction of unsaturated perfluoroolefins, in particular TFE tetrafluoroethylene, in a telogen liquid medium, which is used as an alkyl ketone, characterized in that the free radical reaction is initiated by chemical initiators at a decomposition temperature of the initiator at a molar ratio initiator / TFE / telogen = 0.5 / (0.5-20) / l 00. 6. The method according to p. 5, characterized in that the molar ratio of TFE / telogen is (0.7-3.0) / 100. 7. The product obtained by the method according to p. 4 or p. 6. 8. A method of producing coatings based on fluorotelomers of alkyl ketones, including applying a polymer-containing component to a substrate, followed by drying and heat treatment, characterized in that a solution of fluorotelomer of alkyl ketones is applied to the substrate of different nature, according to one of claims 1, 2 or 7, and heat treatment is carried out at a temperature of 180-200 ⁰ C to obtain a high-quality, continuous coating.