RU2432366C1 - Low-molecular ternary copolymers of vinylidene fluoride and monomer containing fluorosulphate group - Google Patents

Abstract

FIELD: chemistry. ^ SUBSTANCE: invention relates to low-molecular ternary copolymers of vinylidene fluoride and a monomer containing a fluorosulphate group of general formula: , where Rf=-CF2OSO2F, -CF2O(CF2)2OSO2F; l=29-66; m=9-18; n=2.4-4 with number-average molecular weight 3000-9000. ^ EFFECT: obtaining low-molecular ternary copolymers of vinylidene fluoride, having high fluidity, on the basis of which, in the absence of a solvent, cold curing oil-and-petrol resistant sealants can be obtained, having good physical and mechanical properties and having high stability during contact with aggressive media. ^ 1 cl, 5 ex, 2 tbl

Description

The present invention relates to the field of production of low molecular weight ternary copolymers of viiylidene fluoride (WF) containing functional groups, namely copolymers of the general formula:

where R _f = —CF ₂ OSO ₂ F, —CF ₂ O (CF ₂ ) ₂ OSO ₂ F; l = 29-66; m = 9-18; n = 2.4-4;

with a number average molecular weight of 3000-9000.

These copolymers are liquids with a viscosity of 45 to 75 Pa · at 50 ° C, which allows them to be used as thermally aggressive sealants and cold-cured protective coatings that can be used in the absence of solvent. Since the use of a solvent leads to deformation of the sealing layer during the curing process, which makes it impossible to seal closed areas, and at high curing temperatures, the degree of deformation increases significantly, the problem of obtaining cold curing sealants used in the absence of a solvent is especially relevant.

Low molecular weight copolymers of HF and hexafluoropropylene (HFP) with a molecular weight of 1000-22000 are known, containing HF and HFP links in the polymer chain in the ratio of 70:30 to 45:55, respectively, at room temperature, ranging from viscous oils to greases. These copolymers are prepared in bulk at a temperature of 100-250 ° C at their own pressure in the presence of an initiator (e.g. benzoyl peroxide, dicumyl peroxide or acetyl peroxide) and a chain transfer agent (saturated, halogen-free acyclic compound, e.g. methanol, acetone, ethyl acetate), with a molar the ratio of chain transfer agent to the sum of monomers from 0.025 to 1.2 [US Pat. US 3069401, publ. 12/18/1962, IPC C08F 214/22; C08F 214/28; C08F 214/00]. Such copolymers are used as plasticizers for fluorocarbon elastomers to improve their processing. These copolymers are not cured at room temperature and therefore cannot be used to produce sealants and cold cured coatings.

Known copolymers containing units of WF, HFP and perfluoroalkyl vinyl ether of the formula: CF ₂ CFO (CF ₂ ) _n C (O) OCH ₃ , where n = 2-12, obtained by emulsion copolymerization of the above monomers at a temperature of 50 ° C using as an initiator ammonium persulfate at a molar ratio of monomers 1: 0.77: 0.2, respectively [Pat. Great Britain 1145445, publ. 03/12/1969, IPC C2C]. However, these copolymers are high molecular weight, which does not allow their use as solvent-free cold-curing sealants.

The closest analogue to the intended purpose are liquid at room temperature ternary copolymers of WF, perfluoroalkyl vinyl ether (as well as perfluoroalkene) and perfluoroalkyl vinyl ether with an ester functional group, used as cold curing sealants [US Pat. RF 2074199 C1, publ. 02.27.1997, IPC C08F 214/22, C09K 3/10, C09D 127/16]. The molecular weight of the copolymers is 2500-15000. These copolymers are prepared by copolymerization of vinylidene fluoride and comonomers in a solution of 1,2,2-trifluoro-1,1,2-trichloroethane in the presence of a fluoroalkanoyl peroxide initiator. The resulting copolymers cure at room temperature. However, as can be seen from the examples described in the patent description, copolymers with a molecular weight of more than 4,500 cannot be used without a solvent, since they have a high viscosity. On the other hand, these copolymers with a molecular weight of less than 4500 form vulcanizates with low physical and mechanical properties (tensile strength less than 16 kg / cm ² when tensile about 300%). In addition, perfluoroalkyl vinyl esters are difficult to reach compounds.

An object of the invention is to obtain low molecular weight ternary copolymers of WF, having high fluidity at temperatures of 0-50 ° C, on the basis of which in the absence of solvent can be obtained oil-resistant sealants of cold curing, having improved physical and mechanical properties and having high stability in contact with aggressive environments . This goal is achieved by the synthesis of copolymers of the general formula (1):

where R _f = —CF ₂ OSO ₂ F, —CF ₂ O (CF ₂ ) ₂ OSO ₂ F; l = 29-66; m = 9-18; n = 2.4-4;

with a number average molecular weight of 3000-9000.

The copolymers are prepared by reacting WF with HFP hexafluoropropylene and a third monomer containing a fluorosulphate group, namely perfluoroallyl fluorosulphate (PAFS) or perfluoro [(2-fluorosulphate) ethylallyl] ether (PPSEAE). The process is carried out in the presence of an initiator - bis- (perfluoropolyoxaalkanoyl) peroxide of the formula (2):

[C ₂ F ₅ (CF ₂ OCF (CF ₃ )) _x C (O) O] ₂ ,

where x = 1-3, in a solution of 1,1,2-trifluoro-1,2,2-trichloroethane (freon-113) at a temperature of 25-40 ° C.

The molar ratio of WF, HFP and the third monomer is 1: (0.59-0.66) :( 0.08-0.17), respectively, and the molar ratio of peroxide to the sum of monomers is (0.01-0.02): one.

The reaction is carried out under autogenous pressure (not higher than 0.9 MPa) and constant stirring until the pressure drop stops for 3-4 hours. Removing the solvent, the copolymer is isolated in 70-90% yield.

The solvent distilled after isolation of the target product can be reused in the copolymerization processes.

определяют эбулеоскопически, растворяя навеску сополимера в пентафторхлорбензоле. Динамическую вязкость сополимера измеряют на вискозиметре Гэплера.Number average molecular weight

determined ebuleoscopically by dissolving a portion of the copolymer in pentafluorochlorobenzene. The dynamic viscosity of the copolymer is measured on a Gapler viscometer.

The composition and structure of the obtained copolymers are determined using elemental analysis and 19F NMR spectroscopy. 19F NMR spectra were recorded on a Brucker AM-500 spectrophotometer with an operating frequency of 476 MHz, for which solutions of copolymers in hexafluorobenzene were used. The following examples illustrate the invention.

Example 1

41.3 g (0.65 mol) of HF, 60.5 g (0) are charged into a vacuum-cooled and cooled 0.5-liter stainless steel apparatus equipped with a mechanical propeller stirrer, a vacuum manometer, two nozzles for supplying reagents and a jacket for thermostating. , 4 mol) HFP, 36.3 g (0.11 mol) perfluoro [(2-fluorosulphate) ethylallyl] ether, 67.8 ml (0.017 mol) of a 0.28 M solution of bis (perfluoropolyoxaalkanoyl) peroxide of formula 2 (where x = 1) in HFC-113, 66 g (0.25 mol) of 1,2-dibromotetrafluoroethane (HFC 114 B2) and an additional 111.0 ml of HFC 113. The molar ratio of WF: HFP: PPSEAE monomers is sets 1: 0.62: 0.17, respectively, and the molar ratio of peroxide to the sum of monomers is 0.0197: 1. The polymerization is carried out at a temperature of 40 ° C. The initial pressure of 0.81 MPa, within 3 hours, drops to 0.25 MPa. After the end of the pressure drop, the reaction mass is stirred for another 1 h at 40 ° C. Then the reaction mass is transferred to a flask and heated under vacuum (3-4 mm Hg) at a temperature of 150 ° C for 1.5 hours. 114.8 g of a viscous flowing copolymer (yield 83% wt.) Are discharged having a dynamic viscosity (η) at 50 ° C of 63 Pa · s and a number average molecular weight of 5800.

According to the analysis, the structure of the obtained copolymer corresponds to the formula (1), where l = 43.8, m = 12.8, n = 3.0.

The elemental composition (wt.%) Was calculated for a copolymer of formula (1) with the given indices: C = 28.62, F = 64.94, H = 1.38, and it was found (wt.%) For samples of the obtained copolymer by elemental analysis .%): C = 26.4, F = 65.7, H = 2.7.

Example 2

Under the conditions of Example 1, 49.3 g (0.77 mol) of HF, 70.0 g (0.47 mol) of HFP, 22.8 g (0.099 mol) of PAPS are copolymerized in the presence of 91 ml (0.02 mol) of 0 , 22 M solution of bis- (perfluoropolyoxaalkanoyl) peroxide of the formula (2), where x = 1 in freon 113, 76.4 g (0.29 mol) of freon 114 B2 and an additional 154 ml of freon 113. The molar ratio of WF: HFP monomers: PAFS is 1: 0.61: 0.13, respectively, and the molar ratio of peroxide to the sum of monomers is 0.015: 1. The process is carried out at a temperature of 40 ° C for 3 hours and 110.8 g of polymer are isolated (yield 78% wt.).

.The viscosity of the polymer (η) is 52 Pa · s,

.

According to the analysis, the structure of the copolymer corresponds to the formula (1), where l = 29.1; m = 9.1; n = 2.46.

For a copolymer of formula (1) having the above indices, the elemental composition (wt.%) Was calculated: C = 26.43, F = 67.73, H = 0.28; found for the samples of the obtained copolymer by elemental composition (wt.%) ): C = 25.8, F = 68.4, H = 0.6.

Example 3

Unlike examples 1 and 2, the copolymerization is carried out in the absence of dibromotetrafluoroethane. 43.5 g (0.68 mol) of WF, 60 g (0 g) are charged into a 0.5 liter cooled and evacuated stainless steel reactor equipped with a shielded drive motor, a mechanical propeller stirrer, a temperature control jacket and two unions for loading monomers , 4 mol) HFP, 29.9 g (0.086 mol) PPSEAE, 43.2 ml (0.012 mol) of a 0.27 M solution of bis (perfluoropolyoxaalkanoyl) peroxide of formula (2), where x = 1 in HFC 113. Molar ratio WF: HFP: PPSEAE is 1: 0.59: 0.13, and the molar ratio of peroxide to total monomers is 0.01: 1. The polymerization is carried out at a temperature of 40 ° C. The initial pressure is 0.83 MPa and drops to 0.26 MPa within 4 hours. After the end of the pressure drop, the reaction mass was transferred to a round-bottom flask and heated in vacuum (3-4 mm Hg) at a temperature of 150 ° C for 1.5 hours.

89 g (yield 67% wt.) Of a paste-like copolymer having a dynamic viscosity (η) at 50 ° C equal to 91 Pa · s are discharged, and the number average mass is 8300.

According to the analysis, the structure of the obtained copolymer corresponds to the formula (1), where l = 65.9, m = 18.0, n = 3.9.

For the copolymer of formula (1) having the above indices, the elemental composition (wt.%) Was calculated: C = 29.24, F = 64.67, H = 1.49, and for the obtained copolymer by elemental analysis, it was found (wt. %): C = 28.3, F = 65.3, H = 1.8.

Example 4

.Under the conditions of Example 1, 40.7 g (0.637 mol) of HF, 59.6 g (0.397 mol) of HFP, 17.9 g (0.052 mol) of PPSEAE are copolymerized in the presence of 80.4 ml (0.028 mol) of 0.27 M a solution of bis (perfluoropolyoxaalkanoyl) peroxide of formula (2), where x = 1 in freon 113, 42.3 g (0.163 mol) of freon 114 B2 and an additional 114 ml of freon 113. The molar ratio of the monomers WF: HFP: PPSEAE is 1: 0 , 62: 0.08, respectively, and the molar ratio of peroxide to total monomers is 0.021: 1. The process is carried out at 40 ° C for 4 hours and 91 g (yield 77% wt.) Of a polymer, whose viscosity (η) is 72 Pa · s at 50 ° C, are isolated after distillation of unreacted reagents.

.

According to the analysis, the copolymer structure corresponds to formula (1), where l = 48.3, m = 13.8, n = 2.76.

For the copolymer of the formula (1) having the indicated indices, the elemental composition (% wt.) Was calculated: C = 29.4, F = 65.07, H = 1.44. For samples of the obtained copolymer by elemental analysis, it was found (% wt.): C = 28, l, F = 66.2, H = 1.5.

Example 5

.Under the conditions of Example 1, 42.6 (0.66 mol) WF, 66.6 g (0.44 mol) HFP, 30.7 g (0.089 mol) PPSEAE are copolymerized in the presence of 66.7 ml (0.018 mol) 0, A 27 M solution of bis- (perfluoropolyoxaalkanoyl) peroxide of formula 2 (where x = 1) in freon 113, 62.3 g (0.24 mol) of freon 114 B2 and an additional 110 ml of freon 113. The molar ratio of WF: HFP: PPSEAE monomers is 1: 0.66: 0.13, respectively, and the molar ratio of peroxide to the sum of monomers is 0.016: 1. The process is carried out at a temperature of 40 ° C for 3 hours and 12.7 g (87% wt.) Of polymer are released with viscosity (η) 73 Pa · s and

.

According to the analysis, the structure of the copolymer corresponds to formula (1), where l = 48.0, m = 13.5, n = 4.0.

For a copolymer of formula (1) having the indicated indices, the elemental composition (% wt.) Was calculated: C = 28.31, F = 63.28, H = 1.40; for samples of the obtained copolymer by elemental analysis, it was found (% wt. .): C = 27.3, F = 64.2, H = 1.1.

The copolymers obtained in polymers 1, 2, 4, 5 are viscous fluids at room temperature. The polymer obtained in example 3 has the form of a grease and has fluidity at temperatures above 50 ° C.

All copolymers obtained are cured by aliphatic or fatty aliphatic di- and polyamines at room temperature. Hardener is used from 5 to 8 m.h. per 100 m.h. copolymer.

The results of physico-mechanical tests of cured compositions based on the obtained copolymers containing 7-8 parts by weight of hardener xylylenediamine (KDA - a mixture of isomers m: p 75:25) are shown in table 1.

Thus, the ability of all copolymers of the invention to cure at room temperature allows them to be used as the polymer base of sealants and protective coatings in the absence or at a reduced solvent content. The polymers obtained in examples 1, 2, 4, 5 have a reduced viscosity, which allows additional technological additives (adhesives, diluents, fillers, etc.) to be added to the composition. The method of producing low molecular weight copolymers of WF using a monomer containing a fluorosulfate group according to the invention is simple in technological design, does not require large expenditures of time, uses available monomers, while allowing to obtain the target products with high aggressive resistance with high yield.

Table 1 Physico-mechanical properties of vulcanizates based on copolymers obtained in examples 1-5 No.

Third monomer The amount of the third monomer (% of the sum of monomers) Amount of HFC 114 B2 (% of total monomers) The amount of volcanic agent KDA (m. H.) Physico-mechanical properties of vulcanizates after curing 2 days at 25 ° C 1 day at 70 ° C P, kg / cm ² L% P, kg / cm ² L% one 5800 PFSEAE 10 22 8 28 170 36 150 2 3800 PAFS 8 22 7 19-21 180 26 150 3 * 8300 PFSEAE 8 - 7 38 200 49-50 150 four 6100 PFSEAE 5 fifteen 7 32 195 40 150 5 6500 PFSEAE 8 twenty 8 34-36 200 44 150 P - breaking strength L - tensile elongation * - obtained using 10 m.h. solvent

table 2 Physico-mechanical properties of vulcanizates after processing Vulcanizate copolymer Initial Properties Properties after treatment with aggressive gases for 120 h at 70 ° C Hf F Hf + f No. 1 P = 36 kg / cm ² P = 12 kg / cm ² P = 15 kg / cm ² P = 14 kg / cm ² L = 150% L = 250% L = 250% L = 250% Number 2 P = 26 kg / cm ² P = 10 kg / cm ² P = 11 kg / cm ² P = 11 kg / cm ² L = 150% L = 300% L = 250% L = 260% Number 3 P = 44 kg / cm ² P = 24 kg / cm ² P = 28 kg / cm ² P = 27 kg / cm ² L = 150% L = 200% L = 200% L = 200%

Claims (1)

Low molecular weight ternary copolymers of vinylidene fluoride and a monomer containing a fluorosulfate group of the general formula

where R _f = —CF ₂ OSO ₂ F, —CF ₂ O (CF ₂ ) ₂ OSO ₂ F; l = 29-66; m = 9-18; n = 2.4-4 with a number average molecular weight of 3000-9000.