RU2756588C2 - Method for producing thermoplastics - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to the field of production of thermoplastics based on diene hydrocarbons and α-methyl styrene with a complete conversion of α-methyl styrene by anionic copolymerization. The essence of a method for producing thermoplastics with a poly-α-methyl styrene block consists in a two-stage method for producing: at the first stage, butadiene-α- methyl styrene thermoplastics with an incomplete conversion of α-methyl styrene is obtained, at the second stage, after the completion of a reaction of a combination of “living” two-block copolymer poly-α-methyl styrene-polybutadienyllium, n-butyllium and a modifier - mixed alcoholate of alkaline and alkaline earth metals are additionally fed into a polymer solution, and styrene is continuously or by portions dosed there. A copolymerization reaction of residual α-methyl styrene with styrene proceeds with a deep degree of conversion of α-methyl styrene into copolymer with styrene. Next, the resulting solution of block copolymer filled with copolymer of α-methyl styrene with styrene is filled with an agidol-2 stabilizer, isolated by water degassing and dried by known methods.

EFFECT: technical result is that the proposed method for producing butadiene-α-methyl styrene thermoplastics makes it possible to completely polymerize α-methyl styrene (conversion ~100%) and obtain block copolymers with high physical and mechanical properties.

1 cl, 2 tbl

Description

The invention relates to the field of production of thermoplastic elastomers based on diene hydrocarbons and α-methylstyrene. Thermoplastic elastomers can be used in the production of rubber goods and the footwear industry.

Known methods for the production of diene-α-methylstyrene thermoplastic elastomers by sequential polymerization of monomers in a hydrocarbon solvent in the presence of an organic monolithium initiator (UK patent No. 1191605, C08F 207/04, publ. 01.21.68) or a combination of "living" double-block copolymers with a polyfunctional coupling agent ( Federal Republic of Germany patent No. 2442849, C08F 297/04, publ. 03.13.75). The disadvantage of these methods for producing block copolymers is incomplete conversion of α-methylstyrene.

A known method of producing thermoplastic elastomers by polymerization of α-methylstyrene in a hydrocarbon solvent medium under the action of n-butyllithium with the addition of electron donors until an equilibrium concentration is reached, followed by the addition of styrene in an amount of 20-30% to the remaining α-methylstyrene and the continuation of polymerization with further introduction of a conjugated diene and subsequent stitching the resulting product (Japanese patent No. 55-7961, C08F 297/04, publ. 02.26.80). The disadvantage of this method is the decrease in the heat resistance of the polyvinylaromatic thermoplastic elastomer due to the introduction of styrene into the first block.

A known method of producing thermoplastic elastomers by block copolymerization of styrene (or α-methylstyrene) and a diene in an organic solvent of the type (AB) nX, where A is a polystyrene (or poly α-methylstyrene) block, B is a polydiene block, X is a fragment of a coupling agent , n≥2 and type А-В-А - sequential block copolymerization of styrene (or α-methylstyrene) and diene in an organic solvent in the presence of an initiating system n-butyllithium + methyl-tert-butyl ether (MTBE) (USSR patent No. 1661183, C08F 297/04, publ. 07.07.91). The disadvantage of this method is the incomplete conversion of α-methylstyrene, not exceeding 70%. The presence of uncured α-methylstyrene complicates the process considerably.

Wherein:

- the consumption of steam and crumb anti-agglomerate increases when polymer is separated by water degassing;

- additional equipment is used to clean the recycled solvent from unpolymerized α-methylstyrene and to clean the returnable α-methylstyrene;

- the sanitary and toxicological properties of the polymer deteriorate due to the presence of residual α-methylstyrene in it.

The closest in technical essence and the proposed method is a method for producing thermoplastic elastomers (RF patent No. 2129569, C08F 297/04 C08F 6/06, publ. 04/27/1999) by block copolymerization of α-methylstyrene and butadiene in an organic solvent under the action of n- butyllithium in the presence of a modifier - methyl tert-butyl ether, followed by a combination of "living" diblock copolymers with a polyfunctional coupling agent, after the completion of the coupling reaction, copolymerization of the residual α-methylstyrene with styrene is carried out in a block copolymer solution in a ratio of 1: (1-1.5) mol in the presence of an initiating system n-butyllithium: alkali metal alkoxide: methyl tert-butyl ether in the ratio 1: (1-3) :( 3-25), where lithium ethoxide or lithium or potassium butaxides are taken as the alkali metal alkoxide , and as a coupling agent - tetraethoxysilane (TEOS) or dibutyl phthalate (DBP).

EFFECT: invention makes it possible to achieve complete conversion of α-methylstyrene and to increase physical-mechanical and adhesive properties of thermoplastic elastomers. The disadvantage of this method is that alkoxides of alkali metals, ethoxides of lithium, sodium are not soluble in hydrocarbon solvents [D.Zh. Horwood. Industrial application of organometallic compounds // 1979. p. 183]. This complicates the dosing of alkali metal alcoholates, which leads to instability of the process of copolymerization of α-methylstyrene with styrene and the need to constantly adjust their molar ratio.

The technical objective of the present invention is to simplify the synthesis technology and obtain a thermoplastic elastomer with high physico-high physical-mechanical and adhesive properties (adhesion strength of duplicated tissue strips) while achieving complete conversion of α-methylstyrene.

The task in the proposed method is solved by block copolymerization of α-methylstyrene and butadiene in an organic solvent under the action of n-butyllithium in the presence of tetrahydrofuran or methyl tert-butyl ether, followed by a combination of "living" diblock copolymers with a polyfunctional coupling agent, and after completion of the reaction combinations carry out copolymerization of residual α-methylstyrene with styrene in a solution of a block copolymer in a ratio of 1.0: (1-1.5) mol in the presence of an initiating system n-butyllithium: modifier - mixed sodium (lithium) calcium (barium) alcoholate mixtures of high-boiling (above 150 ° C) alcohols: N, N, N ', N'-tetra (β-hydroxypropyl) ethylenediamine (Lapramol-294) and tetrahydrofurfuryl alcohol (THFS) or butyl cellosolve at a molar ratio of Lapramol-294: tetrahydrofurfuryl alcohol in butyl cellulose 1.0: 4.0 and at a molar ratio of n-butyllithium: modifier equal to 1.0: (0.1-0.5) in toluene. The composition of modifiers is shown in Table 1.

The invention is illustrated by the following examples.

Example 1. a). In a three-necked flask with a capacity of 1 L, equipped with a stirrer and a thermometer, 160 g of dried solvent (cyclohexane-gasoline 70: 30%), 436 g of α-methylstyrene, 5.2 g (0.06 mol) methyl tert. -butyl ether (MTBE) and 30 ml of 1 M (0.03 mol) n-butyllithium solution. The polymerization of α-methylstyrene is carried out at a temperature of 18-20 ° C for 3 hours. The content of residual α-methylstyrene in the polymer is 22.9% of the mass. conversion of α-methylstyrene - 66.7%. The resulting solution of "living" poly-α-methylstyrene-lithium (LPMS) is fed to the next stage of polymerization.

b). 5000 g of solvent (cyclohexane: gasoline 70: 30%), 670 g of butadiene and 700 ml of a solution of "living" LPMS obtained under point a) and containing 0 , 03 g of active lithium and 145 g of unpolymerized α-methylstyrene. Polymerization of butadiene is carried out for 1 hour at a temperature of (60-65) ° C. Then carry out the reaction of the combination of "living" two-block in the apparatus is fed 1.56 g (0.0075 mol) of tetraethoxysilane (TEOS). The coupling reaction is carried out at a temperature of (65-79) ° C for 40 minutes. Upon completion of the coupling reaction, the apparatus is cooled to 25 ° C and the content of α-methylstyrene in the reaction mass is determined by chromatography. The content of residual α-methylstyrene in the polymer is 2.8%.

Then, 18 ml of 1 M (0.018 mol) solution of n-butyllithium, 11 ml of modifier M-1 (table 1) are fed into the apparatus, and after 0.25 hours, 128 g of styrene is dosed into the apparatus from the container continuously for one hour, while the molar ratio is unpolymerized α-methylstyrene: styrene is 1.0: 1.0, and the molar ratio of n-butyllithium: modifier M-1 is 1.0: 0.5. At the end of styrene dosing, copolymerization is carried out for another 0.5 hour at a temperature of (20-25) ° C, while the conversion of α-methylstyrene is 98.1% (the content of residual α-methylstyrene is 0.16%). The resulting polymer is isolated by water degassing, stabilized with agidol-2 (1%) and dried on a roller.

The physical and mechanical properties of the obtained thermoplastic elastomer are shown in Table 2.

Example 2. Polymerization was carried out as in example 1, but at the stage of copolymerization of α-methylstyrene with styrene, 20 ml of 1 M (0.02 mol) solution of n-butyllithium, 8.7 ml (0.02 mol) of modifier M- 2 (Table 1) and continuously dosed 190 g of styrene into the apparatus for 90 minutes. The molar ratio of unpolymerized α-methylstyrene: styrene was maintained at 1.0: 1.5, the molar ratio of n-butyllithium: modifier M-2 was 1.0: 0.1. The conversion of α-methylstyrene was 98.8%. The physical and mechanical properties of the obtained thermoplastic elastomer are shown in Table 2.

Example 3. Polymerization was carried out as in example 1, but in the synthesis of poly-α-methylstyryllithium according to item a), 15.8 g (0.18 mol) of tetrahydrofuran were fed. Conversion of α-methylstyrene in the synthesis of poly-α-methylstyryllithium - 70%. At the stage of copolymerization of α-methylstyrene with styrene, 60 ml of 1 M (0.006 mol) solution of n-butyllithium, 5.2 ml (0.012 mol) of modifier M-3 (Table 1) were fed into the apparatus and 128 g of styrene was continuously dosed into the apparatus for 60 minutes. The molar ratio of n-butyllithium: modifier M-3 is 1.0: 0.2, the conversion of α-methylstyrene is 98.9%. The physical and mechanical properties of the obtained thermoplastic elastomer are shown in Table 2.

Example 4. Polymerization was carried out as in example 1, but at the stage of copolymerization of α-methylstyrene with styrene according to item a), 2.4 ml of 1 M (0.0025 mol) solution of n-butyllithium, 0.96 ml (0 , 0025 mol) modifier M-4 (table 1) and continuously dosed into the apparatus 128 g of styrene for 60 minutes. The molar ratio of unpolymerized α-methylstyrene: styrene was maintained at 1.0: 1.5, the molar ratio of n-butyllithium: modifier M-4 was 1.0: 0.5. The conversion of α-methylstyrene was 98.7%. The physical and mechanical properties of the obtained thermoplastic elastomer are shown in Table 2.

Example 5. Polymerization was carried out as in example 1, but at the stage of copolymerization of α-methylstyrene with styrene according to item a), 2.4 ml of 1 M (0.0025 mol) solution of n-butyllithium, 0.96 ml (0 , 0025 mole) modifier M-5 (table 1) and continuously dosed into the apparatus 128 g of styrene for 60 minutes. The molar ratio of unpolymerized α-methylstyrene: styrene was maintained at 1.0: 1.5, the molar ratio of n-butyllithium: modifier M-5 was 1.0: 0.5. The conversion of α-methylstyrene was 99.5%. The physical and mechanical properties of the obtained thermoplastic elastomer are shown in Table 2.

Example 6. (according to the prototype).

a). Synthesis of lithium poly-α-methylstyrene (LPMS).

In a three-necked flask with a capacity of 1 L, equipped with a stirrer and a thermometer, 160 g of dried solvent (cyclohexane-gasoline 70: 30%), 436 g of α-methylstyrene, 3.52 g (0.04 mol) methyl tert. -butyl ether and 20 ml of 1 M (0.02 mol) n-butyllithium solution.

The polymerization of α-methylstyrene is carried out at a temperature of 18-20 ° C for 3 hours. Conversion of α-methylstyrene - 70%. The resulting LPMS solution is fed to the next polymerization stage.

b). Synthesis of butadiene-α-methylstyrene thermoplastic elastomer.

2500 g of solvent (cyclohexane: gasoline - 70:30), 350 g of butadiene and 700 ml of LPMS solution obtained according to item a) and containing 0.04 d-and active lithium and 131 g of unpolymerized α-methylstyrene. Polymerization of butadiene is carried out for 1 hour at a temperature of 60-62 ° C. Then carry out the reaction of the combination of "living" two-block with dibutyl phthalate. 1.4 g (0.005 mol) of dibutyl phthalate is fed into the apparatus and crosslinking is carried out at a temperature of 70 ± 2 ° C for 40 minutes. The content of residual α-methylstyrene in the polymer is 2.8%. At a temperature of 25 ° C, 18 ml of 1 M (0.018 mol) solution of n-butyllithium and 70 ml of modifier M-4 (table 1) are fed, after 15 minutes, 128 g of styrene are continuously fed for 60 minutes. At the end of the styrene dosing, the copolymerization is carried out for another 60 minutes at a temperature of 20-25 ° C. The conversion of α-methylstyrene was 97%, the residual α-methylstyrene was 0.18%. The polymer was stabilized with a 1% solution of agidol-2, isolated by water degassing, and dried on a roller.

The physical and mechanical properties of the obtained thermoplastic elastomer are shown in Table 2.

From the above examples and the data in Table 2, it follows that the proposed method will simplify the technology for obtaining thermoplastic elastomers, reduce the time of copolymerization of styrene and α-methylstyrene from 75 minutes to 45-60 minutes, upon reaching a higher conversion of α-methylstyrene, and also increase the adhesion strength of duplicated strips of fabric.

Claims (1)

A method of obtaining thermoplastic elastomers by block copolymerization of α-methylstyrene and butadiene in an organic solvent under the action of n-butyllithium in the presence of tetrahydrofuran or methyl tert-butyl ether, followed by a combination of living diblock copolymers with a polyfunctional coupling agent, and after completion of the coupling reaction is carried out copolymerization of residual α-methylstyrene with styrene in a solution of a block copolymer in a ratio of 1.0: (1-1.5) mol in the presence of an initiating system n-butyllithium and a modifier, characterized in that mixed sodium (lithium) calcium is used as a modifier (barium) alcoholate of a mixture of high-boiling (above 150 ° C) alcohols: N, N, N ', N'-tetra (β-hydroxypropyl) ethylenediamine (Lapramol-294) and tetrahydrofurfuryl alcohol (THFS) or butyl cellosolve at a molar ratio of Lapramol-294 : tetrahydrofurfuryl alcohol or butyl cellosolve, equal to 1.0: 4.0, and at a molar ratio of n-butyllithium: modifier equal to 1.0: (0.1-0.5), in toluene.