SU767140A1 - Method of preparing rubber-like copolymers - Google Patents

Description

(54) METHOD FOR PREPARING RUBBER-LIKE COPOLYMERS

I

The invention relates to the field of copolymer chemistry, more precisely to the production of graft rubber-like copolymers, which can be used in the field of synthetic rubber, in the preparation of film coatings for electrical insulation purposes, in the manufacture of rubber and cable products, in the building materials industry and in other areas of the national economy. .

The prior art method of preparing rubber-like copolymers by copolymerizing low molecular weight diorganosiloxane rubber with styrene when heated in organic solvent in the presence of isobutyric acid dinitrile initiator 1 is known.

This method has a number of significant drawbacks that limit its industrial application. The method is not technologically advanced due to the fact that the process of radical polymerization is extremely sensitive to the presence of impurities in the reaction medium, and in particular to the presence of traces of oxygen. Because of this, there is a need

thorough cleaning of monomers from impurities and dissolved air. In addition, the copolymerization process must be carried out in a vacuum or in an inert atmosphere thoroughly cleaned from traces of air, which makes the copolymer production technology very difficult. Another disadvantage of the existing method is onacHijcTb structuring in the process, i.e. the formation of an insoluble product due to the uncontrolled grafting of polystyrene chains to the CH3 groups of methyl (vinyl) sioxane used. The structured products are practically not processed and are not of practical value as elastomers for the production of rubber.

15 mixtures and materials based on them. The same applies to highly branched and partially onit products, but not yet reached the stage of structuring. Such products have many branch centers randomly distributed along the chain, as a result of which they are worse processed, poorly combined with rubber rye ingredients and organic solvents, have a lower value as elastomers, and materials based on them have degraded physicomechanical properties. . The purpose of the invention is to simplify the process technology, control the degree of grafting and obtain soluble copolymers capable of further processing by hot and cold vulcanization. The goal is achieved by the fact that according to the proposed method, the oligostion with carbocyclo siloxane of the general formula is carried out: ((| H-CHg}; 1-С Н-ЙНгCjHsД510 (61ЯВ 0) 7Г-} V where m 1-50, п 2, 3, R, R, R is methyl, phenyl with diorganocyclosiloxanes at a ratio (wt.%) 2.5-47.0: 53.0-97.5, respectively, and the process is carried out at 80-130 ° C. It is possible to carry out the process of copolymerization of these oligomers with a mixture of diorganocyclo siloanes of various structures or with diorganocyclo siloxanes of mixed composition. In these cases, graft copolymers are formed, polyorganosiloxane chains which contain heterogeneous siloxane units. The essence of the method is that the oligosylescarboxylic acid cyclosiloxanes of the above formula are heated in solution in the presence of an ionic initiator and aterate is used, aterate of ailment, aterate, ailine, ateryteps. Sanitary rubber rubbers, for example, alkali metal derivatives and substituted ammonium and phosphonium salts (hydroxides, carbon monoxide) lanol you, alcohol, fluoride, sulfuric acid and its salt halides of boron, aluminum, titanium, iron). The choice of polymerization initiator is determined by the nature of the diorganocyclosiloxane used. In cases where the polymerization is carried out with organohydrocyclicsiloxanes containing SiH groups, it is preferable to catalysts, whereas in the case of organocyclosiloxanes containing aryl substituents SiAr instead of acidic catalysts that cleave SiAr groups, it is more expedient to use basic polymerization catalysts. . The concentrations of the initiators used are analogous to those used in the synthesis of conventional siloxane rubbers. The polymerization is carried out in the medium of organic solvents used in the synthesis of siloxane rubbers, for example, in toluene, benzene, gasoline, xylene, gentane. 4 The mode of copolymerization is determined by the type of organocycloxane used and the nature of the ionic polymerization initiator. When using stressed organocyclotrisiloxanes, as well as in the case of using acidic acidifiers and derivatives of ammonium and phosphonium salts, the copolymerization process is carried out at moderate temperatures — up to 120 ° C, while less stressed organocyclosiloxanes and other catalysts of the main character require higher temperatures — from 110 With and above. The presence of an inert solvent in the reaction zone. Promotes better compatibility of the used reagents, especially at the initial stages of the process, inhibits the development of side reactions at deep stages of conversion and thus favors the formation of copolymers of a more homogeneous composition. The solution obtained after the reaction is neutralized (stacked), binding the residues of the initiator, after which the copolymer is isolated either by precipitation with a blunt of methyl (ethyl) alcohol, or by removal of the solvent and subsequent drying. The finished product is additionally evacuated from residual solvent and precipitator in a vacuum dryer at temperatures up to 140 ° C and a pressure of 1-2 mm Hg. Art. The resulting copolymers are characterized by the content of diorganosiloxane units. (by NMR spectroscopy), silicon content (by elemental analysis) and intrinsic viscosity, determined in toluene solution at 25 ° C. Example 1. In a flask equipped with a stirrer and an opening for sampling, 0.69 g of oligostyrenecarbocyclo siloxane - {sn-cng) y15-sn-cngCsHg CH3 1o TsSbN5 2% 0.034 g potassium hydroxide, 4.6 ml toluene. The flask with the reaction mass is heated in a thermostat at 110 ° C for 0.5 h with constant stirring. Then, 2.25 g of octamethylcyclotetrasiloxane (CH3) 231O) 2 (at the rate of 100 units (CH3) of 25H-1 carbocyclosiloxane link in the chain of oligomer) are introduced. The resulting mixture was stirred at CL-120 ° C for 40 hours. The specific viscosity of the reaction mass gradually increased and reached a value of 0.75 dl / g (1% solution in toluene at 25 ° C). The reaction mass is diluted with toluene, after which the polymer is recovered by reprecipitation. added a double volume of ethanol. Redeposition is repeated twice. After drying in vacuo, an elastic kaichy-like product is obtained that is soluble in benzene and toluene. The yield of the copolymer according to NMR spectra is 73%. In the NMR spectra of the obtained copolymer, there are characteristic proton absorption signals of the 5 (CH3) 2 groupings in the range of 0-2.0 ppm, CH-CHerpyitn protons in the range of 3.0-4.5 ppm, CeHs-rpytra protons in the area of 6.0-7.0 .m. The content of dimethylsiloxane units in the copolymer chain calculated on the basis of NMR spectroscopic data averages 80 units per each unit of oligosyrene, carbocyclosiloxane containing one carbocyclosiloxane fragment. Example 2: A device similar to that described in Example 1 is placed with 0.51 g of oligosylate carbon sample. Cn-h g m CeHs CHs iotsitCjHg jO: 0.018 g of hydroxide} 1 and 2.6 ml of toluene are added. After 1 h stirring at 110 ° C. 1.32 g of octamethylcyclotetrasiloxane was added (at the rate of 56 units per carbocyclo-loxane unit in the chain of the oligomer). The reaction mass is stirred for 30 hours, gradually raising the temperature to A7-120 ° C and the solvent is partially distilled. Monitoring of the reaction is carried out by changing the specific viscosity of a 1% solution of a sample of the reaction mixture in toluene. After re-precipitating twice, an elastic copolymer was obtained with a yield of 65%, a specific viscosity of 0.55 dl / g, containing 30% Si. Example Z. In a device similar to that described in Example 1, 0.39 g of oligosyrolecarbocyclo siloxane of the formula CH-CHi) ijjCH-CH2 CgHsCHjSio Sio (CsH5 0.016 g of potassium hydroxide and 3.3 ml of toluene are placed. After 20 minutes of movement at 110 ° C, add 1.23 g of octamethylcyclotetrasiloxane.The reaction mass is stirred for 20 hours with a gradual increase in temperature to 115-117 ° C. The reaction is monitored by changing the viscosity. After 3 hours of heating, the specific viscosity of the reaction mixture sample in toluene, it is 0.20 dl / g, the viscosity is further increased to 0.60 dl / g. After double re-precipitation, a white elastic rubber-like copolymer with a yield of 70% and a specific viscosity of 0.6 dl / g was isolated from the diluted solution with a yield of 0.6 dl / g. Example 4. According to the procedure similar to examples 1 and 2, from 0.39 g of bore cycropylcarbosiloxane - CH- CHzt; CH-Cllj, ciijSio Si (CsHs) j% 0,016 g of potassium hydroxide and 1.28 g of hexamethyl cyclotrisiloxane (CH3) in 3.3 ml of toluene after 11 h of heating at 110 I 5 ° C, an elastic rubbery copolymer was obtained (yield 68%). PRI me R 5. According to the procedure similar to that shown in example 1 and 0.37 g of oligostirolcarbocyclosiloxane of the formula -.CK-CHj-jyfH-CH CsHs CH3Sio go ()} q 0.068 g of tetramethylammonium hydroxide, 4.68 g of methylmethyltriphenylcyclotryloxane in the presence of 7.7 ml of toluene after 8.5 hours of heating, with a yield of 36.7% (according to gel chromatography), a copolymer with a specific viscosity of 0.41 dl / g was obtained. Example 6. According to the method similar to that shown in example 1 and 2, from 0.21 g of oligostirolcarbocyclosiloxane, the structure is CH-cd cpc HSCHjSio 5i (CjH5) 7.21 g of trimethyltriphenylcyclotrisiloxane, 0.090 g of tetramethylammonium hydroxide in a solution of 22.4 ml of tin, in a solution of 22.4 ml of 22.4 ml With 8.0 hours of heating, a liquid copolymer with a specific viscosity of 0.23 dp / g and a yield of 42% was obtained (according to gel chromatography). Example 7. According to a procedure similar to that shown in example 1 and 2, from 0.17 g of oligostirolcarb. Cyclosiloxane of the structure -fCH-cHg) - sc-cngCgHsCHjSio $ i (. 5.27 g of tetramethylcyclotetrasiloxane, 0.073 g HI S04 (60 wt. %) in 286 ml of toluene after 13 h of heating: a viscous copolymer with a specific viscosity of 0.19 dL / g and a yield of 57.6% was obtained at 80 ° C (according to gel chromatography). Example 8. By the method similar to examples 1 and 2, loaded with 0.43 g of oligostirol carbocyclo siloane of the formula At 110-117 ° C, the specific viscosity of the reaction mass rises to 40 dl / g. After two reprecipitations, 3.6 g (55%) of an elastic rubbery copolymer was obtained. Example 9. In a device similar to that described in Example 1, 0.35 g of oligostirolcarbocyclosiloxane of the formula - {rK-2-ferCH-C% CgHs with an average of $ 1 og (CeH5), 01 g of H330 (80% concentration) and , 2 m benzene. After 0.5 h of stirring at 85 ° C, 0.39 g of tetramethylcyclotetrasiloxane (CH351Hp) 4 (mixture of isomers) is introduced. The reaction mass is heated at the same temperature for 15 h; the specific viscosity of the reaction mass was 0.33 dp / g. After double precipitation, liquid copolymer was obtained with a yield of 43% of theoretical ... The NM spectra of the obtained product contain absorption signals characteristic of the following groups: SiCHj (in the range of 6-2.0 ppm), SiH (in the range of 4.6-4.8 ppm), -CH2-CH- (in the region of 3.0-4.5 ml.), -CgHj (in the region of 6.0-7.0 ppm) Calculated based on NMR spectroscopic data, the content of methylhydrosiloxane

1Gor cha

-118.

130-140С

Cold 20 ° С

-105

Hot air 130-140 ° С

-115

Cold + 20 ° С

-110

Cold 20 ° С

-115

The presence in the vulcanizates of several temperature transitions, characteristic for both polystyrene and organosiloxane blocks, indicates the presence of a block structure of macromolecules copolymers.

767140

95

240

-45

235

95

-40

245

+120

-55

250

+105

270

-47

+110

Claims (1)

Thus, the method according to the invention has significant advantages over the known. First of all, the process does not require the use of special measures to protect it from the oxygen of the air and can be produced as links in the copolymer chain is about 50 for each carbocycloxane unit in the oligomer chain. Example 10. According to a procedure similar to that shown in examples 1 and 2, from 0.21 g of oligosgyrolcarbocyclosiloxane of the formula - (cn-cnH CH-c3i cNs31o 51 {CbH5), 0.009 g of hydroxide and 0.70 g of trimethyltriphenylcyclotrisiloxane (Cn3) CgHs SiO 3, 3.2 ml in toluene solution, after 13 hours of heating at 130 ° C with a yield of 52%, an elastic rubbery copolymer with a specific viscosity of 0.36 dL / g was obtained. The copolymers obtained in examples 1-10 j subjected to vulcanization. The vulcanization is carried out in the form of hot and cold vulcanization using the following ingredients, parts by weight: copolymer 100, dicumyl peroxide 1.5 (hot vulcanization), methyltriacetoxysilane 5, O cold vulcanization). The results of the thermomechanical study of the obtained vulcanizers are given in the table. 976 Nitelio simple equipment. According to the proposed method, rubber-like products of copolymerization can be obtained in a wide range of molecular weights and viscosities, completely soluble in common organic solutions of siloxane rubbers and separated from solutions by conventional methods. Therefore, this method can be easily carried out on conventional equipment used to obtain polyorganosiloxane rubbers. without any additional changes in the technological scheme, and there is no need to apply special techniques that increase the cost of HF production. In addition, since the branching of the resulting copolymers is determined by the number of carboxiloxane fragments in the chain used in the carboxyliccarbocyclo siloxane, it is possible to control the degree of branching and to obtain copolymers of different structure and composition according to the ratio of M polystyrene and polysiloxane blocks in the macromolecules of the copolymers. The similar structure of the resulting copolymers also facilitates the vulcanization of these products by hot and cold vulcanization. The ability to cure opens up the possibility of obtaining rubber with new valuable special properties. for example, with increased durability, strength, oil and benzoskostkrstyu, adhesion to various materials. The method of obtaining rubber-like copolymers by copolymerization of organocyclosiloxanes in the presence of ionic initiators by heating in an inert organic solvent, characterized in that, in order to simplify the process and to obtain soluble graft copolymers with an adjustable degree of grafting, you are copolymerized with a carcicrococliocrocolycroclycroclycrocrocolycrocroclycrocrocolycrocrococcicrococcylcoccylcoccylcoccylcoccylcoccylcoccylcicrococcylcoccicrococcylcoccylcoccicrococcicroclic ocerocents case. -c; n -CHNCgHsBgio (SiRK o) 7-7 m 1-50, n 2, 3, R, R, R methyl, phenyl with dioorganocyclo siloxanes in a ratio (wt.%) 2.5 - 47; 53, 0 - 97.5 corresponding but also the process is carried out at 80-130 ° C.. Sources of information received note in the examination 1. Copyright certificate USSR № 516712, cl. C 08 G 77/04, 1977 (the prototype).