SU749852A1 - Method of producing fibre-forming acrylonitrile copolymers - Google Patents

Description

(54) METHOD FOR OBTAINING FIBER-FORMING ACRYLONITRILE COPOLYMERS The invention relates to the preparation of acrylonitrile-based fiber-forming copolymers and can be used in the production of synthetic fibers. . There are known methods for producing fiber-forming copolymers of acrylonitrile by copolymerizing acrylonitrile or its mixture with vinyl monomers with malein anhydride in the presence of radical type catalysts in a non-polar medium; aliphatic and acyclic hydrocarbons 1, 2 and h. To obtain copolymers with improved uniformity in composition, the process is carried out in non-polar oliphatic or alicyclic hydrocarbons at a temperature below 8 and the concentration of the mixture of initial monomers is 20-30%. In this case, the copolymers have a fairly high uniformity in composition (to 1.7) and a low value of the copolymerization constant (Gdts 2.06). However, the disadvantage of these methods is their duration (2-8 hours) with low conversion (20-60%) and high comonomer content in the initial reaction mixture. In addition to Tjiro, aliphatic and acyclic hydrocarbons used as solvents are toxic and easily flammable. The closest to the proposed technical essence is a method of producing fiber-forming acrylonitrile copolymers, in which the copolymerization of acrylonitrile with compounds having a double bond is carried out in a concentrated aqueous solution of sodium sulphate at 60-80 ° C in the presence of catalysts radical type (azodiisobutyronitrile) and a uniform flow during the process of a more active monomer into the reaction mixture 4. The advantage of this method is for -. obtaining a copolymer of uniform composition. The disadvantage of this method is its duration (1.5-4 hours) and low yield of copolymers (56%). The purpose of the invention is to reduce the duration of the process and increase the yield of copolymers. This goal is achieved by the fact that the method of obtaining fiber-forming acrylonitril copolymers by

polymerization of acrylonitrile or its copolymerization with the United, having a double bond, in an aqueous concentrated solution of sodium anhydride with a radical type catalyst, when heated, is carried out in the presence of 2-3 wt.% maleic anhydride, at pH 4.0-5.5. .

Under these conditions, the copolymer yield is 75-80%, and the process time is 20-30 minutes.

Because maleinrvy anhydride under copolymerization conditions to form a complex compound of sodium thiocyanate, eliminating the need for dispensing more active component (maleic anhydride) prisopolimerizatsii, since the complex compound obtained does not form homopolymers, acrylonitrile and maleic sopoliMejpH angIdrid6m have a uniform composition.

The process is carried out at an initial concentration of comonomers of 13.115, 5 wt.% And a temperature of 70-80 C.

The required pH of the medium is created with caustic soda.

The original aqueous solution of rhodium sodium has a concentration

70

1.31.51, 5% and density d

As a radical-type catalyst, azodiisobutyronitrile can be used, injected in an amount of 1% by weight of the copolymers.

The copolymerizable acrylonitrile compound having a double bond, can also be methacrylate. The ratio of comonomers and maleic anhydride in the initial mixture should be in the range of 97-98: 3-2 wt.%.

At the end of the process, the reaction solutions after filtration and deaeration can be used to form the fiber.

EXAMPLE 1. In a concentrated aqueous solution of roDanistog. Sodium (51.5%, d 1.31) dissolve the maleic anhydride and adjust the pH of the sodium diluent with caustic soda to 4.0. Azodiisobutyronitrile (1% by weight of comonomers) is dissolved in acrylonitrile and added with stirring to a solution of maleic anhydride in sodium Rodanide.

The ratio of acrylicOnitrile: maleic anhydride is 98: 2 (wt.%); the comonomer concentration in the solution is 13.1%. The copolymerization process is carried out at 70 s for 25 minutes. At the end of the reaction, the solution is cooled. The output of the copolymer is 82%. Working in the solution solution 270 s. The specific viscosity of a 0.5% solution of a copolymer in dimethylformamide 1, V. ,

P me R 2. Preparation of the reaction mixture as in example 1

The ratio of acrylonitrile: maleic anhydride is 98: 2 (wt.%); comonomer concentration 13, 1%;,. initiator 1% by weight of comonomers; pH 5.0 t. The duration of the copolymerization of 20 minutes; 1.95. Yield 80%. Working viscosity 280 sec.

Froze Preparation of the reaction mixture as in example 1

The ratio of acrylonitrile: maleic anhydride -98,2 (wt.%); comonomer concentration of 13.5 wt.%; pH 5.5; T isopropyl alcohol 5% by weight of comonomers. The copolymerization duration is 20 min, g., 1.6. Yield 76%. Working viscosity 235 s.

PRI me R 4. Preparation of the reaction mixture as in example 1.

The comonomer ratio is 97: 3 (wt.%); Comonomer concentration is 13.5 wt.%; Initiator is 1% by weight of comonomer; ,five. The duration of the copolymerization of 25 minutes; T 80 ° C; Pud. 1.75. The yield is 80%. Working viscosity 250 s.

PRI me R 5. Preparation of the reaction mixture as in example 1

The copolymerization of acrylonitrile, methyl acrylate, maleic anhydride is carried out at a ratio of 92: 5: 3 (wt.%), Respectively. The comonomer concentration is 13.1% by weight; initiator 1% by weight of comonomers; pH 5; T 80 C. Duration of copolymerization 20 min; d) ,,,, 1.56. The yield is 77%. Working viscosity 230 s.

EXAMPLE 6 Maleic anhydride and methyl acrylate are dissolved in a concentrated aqueous solution of rhodium sodium (51.5%, 1.31). Adjust the pH of the solution with caustic soda to 5.0. The initiator azodiisobutylonitrile (0.8% by weight of the co-homols) is dissolved in acrylonitrile and added with stirring to a solution of maleic anhydride and methyl acrylate in sodium Rodanide. The ratio of acrylonitrile: methyl acrylate: maleic anhydride is 93: 5: 2 wt.%, The concentration of comonomers in the solution is 13.1 wt.%. The copolymerization process is carried out for 30 minutes. The yield is 80%. Working viscosity 230 a

Pud. 18 Example 7. Preparation

reaction mixture as in Example 6.

The variety of acrylonitrile: methyl acrylate: small einovogo anhydride 91: 6 J 3 weight. %, CONCENTRATION | 5 aci of comonomers 13.1 wt. %; p H 5.5, temperature 70s. The copolymerization duration is 25 minutes. The output is 76. Working viscosity 210 s, f beats 1.65.

PRI me R 8. Preparation of the reaction mixture as in example 6.

The ratio of acrylonitrile: methacrylate: msheic anhydride - 92: 5: 3 wt.%; concentration with pH 5.5; temperature copolymer yield - 80%. Worker 1.55. PRI me R 9. Pr from binary copolyme maleic anhydride f air. Formation is drafted under the following mode. Spinning solution feed rate, Acceleration admission rate, m / min Discharging rate, m / min Concentration of NaCNS in the precipitation bath,% Spinning solution temperature. Precipitation bath temperature, ° С First stretch Second stretch (glycerin), 0 Total stretch ratio, times Filler of platinum – radium, mm Example 10. Insulation of a fiber from a base acrylo acrylate: maleic an (92: 6: 2 wt. %). Molding Mode: Spraying Feed Rate,

Data of physicomechanical and thermogravimetric tests on fibers made from copolymers of acrylonitrile and maleic anhydride Acceleration biscuit velocity, m / min 0.63 Extract biscuit velocity, m / min3.42 NaCNS concentration in the precipitation bath,% 14-15 Temperature of the diluent solution, ° С 18 Temperature of precipitation bath, ° С 8-10 First stretch (glycerin), from 105-110 Second stretch (glycerin), ° С 140-145 Total extraction ratio, times 11 Filters of platinum radium, mm300x0.08 Physicomechanical properties examples obtained by examples 9, 10: Elementary number 6000-7000 Relative a strength 31-38 gf / tex Elongation at break - 12-18%. The data on the physicomechanical and mogravimetric characteristics of the fibers obtained are presented in the table. The use of the invention will reduce the process of obtaining fiber-forming acrylonite copolymers containing reactive and idrid groups, which make it easy to dye the co-optic fibers with available dyes to 30 minutes and increase the yield of the target duct to 75-80%.

EV EK% 3.5

37

33

36

38

32 294 295 300 290 292

190 21

195

190

160

190

22

25

22

22

9.0

5.7 4.5 5.2

7: -; - Mr. - ; -: .- -..--.,

Claims (4)

1. Certificate of authorship 382546, cl. C 08 F 220/44, 01.25.71. -, 2. The copyright certificate number 429069, cl. C 08 F 22b / 44, C 08 F 222/06, 25.06.70. 3. The copyright certificate 408555, cl. C 08 F 220/44, C 08 F 222/06, 26.J1.71., 4. The author's certificate 183390, cl. D 01 F b / b, C 08 F 220/1, C 08 L SI / O, C 08 L 33/20, 14.09.64 (proto