RU2442796C1 - Way of production of modified 1,4-cis-polybutadiene - Google Patents

Abstract

FIELD: rubber industry.

SUBSTANCE: invention refers to production of modified cis-1,4-polybutadiene with the presence of the Ziegler-Natta catalyst systems; the obtained polymer is used in manufacturing of general mechanical rubber goods, tyres with good operational characteristics. The way of production is performed by means of butadiene polymerization in the hydrocarbon solvent with the presence of the neodymium-containing catalyst with further addition of a modifier and antioxidant, extraction and drying of the polymer; as a modifier, low molecular non-saturated polyketones are used that contain from 0.1 to 16 weight % of oxygen in the form of carbonyl group and double carbon-carbon bonds; the number average molecular weight of the polyketones is from 5,500 to 15,000; the polyketones are introduced into the polymerizate in the course of monomer conversion that equal or exceed 95 % in the amount from 1 to 40 mmol/kg of butadiene (0.2-12.0 g/kg of butadiene) that goes to polymerization at continuous mixing within 15-60 min. at the temperature of 55-85°C; as a neodymium catalyst, neodymium ethylhexylphosphate or neodymium versatat is used; after the modification process has been completed, the antioxidant in the amount of 4-5g/kg of the ploymer is used.

EFFECT: production of cis-1,4-polybutadiene with the Mooney viscosity of 40-50 n. units, with narrow MMD (<2.5), low cold flow (<25 mm/hour) and improved characteristics of vulcanizing agents.

4 cl, 2 tbl, 16 ex

Description

The invention relates to a technology for producing modified cis-1,4-polybutadiene under the influence of Ziegler-Natta catalytic systems and can be used in the UK industry, and the resulting polymers in the production of rubber products, various types of tires with high performance.

A known method of producing cis-1,4-polybutadiene using a catalytic system based on compounds of rare-earth compounds (REE) (RF patent No. 2248845, IPC B01J 37/04; C08F 04/52, 36/06, publ. March 27, 2005 )

In the above invention, the polymerization of butadiene is carried out under the influence of a catalytic complex preformed in the presence of monomer, consisting of carboxylate or phosphate of rare-earth metals, an aluminum compound (the most commonly used is triisobutylaluminium (TIBA) and diisobutylaluminum hydride (DIBAG)), a chlorinating agent (ethylchloride).

The disadvantage of this invention is that cis-1,4-polybutadiene with a narrow molecular weight distribution of macromolecules (<2.5) due to the strictly linear structure of the molecular chains is characterized by high plasticity and cold flow.

High ductility and cold flow of cis-1,4-polybutadiene requires additional energy consumption when separating it from solutions and drying on drying units (reduced equipment performance due to increased ductility and stickiness of rubber). Such rubbers are poorly transported (spread) in any container (bags, containers, etc.) and poorly stored in warehouses of both manufacturers and consumers.

It is known that in order to reduce cold flow and ductility of cis-1,4-polybutadiene, various post-polymerization agents (phosphorus, tin, silicon chloride and other compounds) are used to branch the polymer chain. However, these methods have not found practical application due to their insufficient environmental friendliness (L. Friebe, O. Nuyken, W. Obrecht "Ziegler-Natta catalysts based on neodymium and their application", p. 56, 2001).

The closest in technical essence and the achieved result to the proposed method is a method for producing polybutadiene (US patent 7.112632 B2, IPC C08F 8/08, C08F 136/06), based on the use as agents of modification of epoxidized vegetable oils, epoxidized polybutadiene, maleated polybutadiene ( Ricon), epoxidized copolymers of dienes.

The disadvantage of this method is that all of these modifiers are expensive.

A known method of modifying rubber compounds and rubbers using low molecular weight unsaturated polyketones (RF patent No. 2345101, IPC C08J 3/20, C08L 21/00, C08C 19/04, publ. January 27, 2009), where the modified rubber compound is prepared by simple simultaneous or sequential mixing of all necessary components (high molecular weight rubber, low molecular weight unsaturated polyketone, fillers, vulcanizing agents, plasticizers, etc.), as well as adding low molecular weight rubber to the finished rubber compounds with their subsequent mixing vanyu. Mixing and manufacturing of the rubber composition is carried out on standard mixing equipment - rollers, rotary or screw mixers. However, this modification method is quite energy-consuming and requires a significant consumption of polyketones.

An object of the present invention is a method for producing modified cis-1,4-polybutadiene with a Mooney viscosity of 40-50 conventional units, narrow MMP (≤2.5) and low cold flow (not more than 25 mm / hour).

The technical result of the invention is to obtain cis-1,4-polybutadiene with reduced ductility and cold flow, which facilitates the isolation of rubber from the solution, improves the shape of the rubber briquettes during storage and transportation, and also improves the properties of vulcanizates based on it. In addition, the use of unsaturated polyketones as modifiers will make it possible to reduce the cost of manufactured rubber, since polyketone production costs are significantly lower than the cost of modifiers used in the production of modified 1,4-cis-polybutadiene. Using this method does not require significant capital costs.

This object is achieved in that the modified 1,4-cis-polybutadiene is prepared by polymerizing butadiene in a hydrocarbon solvent in the presence of a neodymium-containing catalytic complex, followed by the addition of modifiers in an amount of 1-40 mmol / kg of butadiene at a polymer conversion of ≥95% at a temperature of 55- 85 ° C. As modifiers, liquid polyketones are used, with a number average molecular weight of 5500-15000, containing from 0.1 to 16 wt.% Oxygen in the form of carbonyl groups and double carbon-carbon bonds. The advantage of liquid "polyketones offered as modifiers is that they are obtained from polybutadiene and oligodienes, without the use of catalysts or expensive reagents.

Unsaturated polyketones used as a modifier with the required content of carbonyl groups and the necessary molecular weight are obtained by non-catalytic oxygenation of cis-1,4-polybutadiene rubber with nitrous oxide (N ₂ O) at a temperature of 50-350 ° C and a pressure of N ₂ O 0.01 -100 atm according to the patents [RF Patent No. 2230754, prior. 05.23.2003, IPC C08F 8/06; C08C 19/04. RF Patent No. 2235102 prior. 05/23/2003, IPC C08F 8/06; C08C 19/04. RF patent No. 2283849, prior November 17, 2004, IPC C08F 8/06; C08C 19/04. RF patent No. 2280044, December 16, 2004, IPC C08F 8/06; C08C 19/04. EP 1627890 (B1), 17.09. 2008, KADubkov, et al .; Pat. US 7385011 (B2), 06/10/2008, KADubkov, et al.].

The unsaturated polyketones obtained in this way are low molecular weight polymers containing ketone (> C = O) functional groups statistically distributed along the polymer chain, as well as butadiene units with double carbon-carbon bonds [KADubkov et al., New reaction for the preparation of liquid rubber, J. Polym. Sci., Part A: Polym. Chem. 44 (2006) 2510; S.V. Semikolenov et al., Ketonization of a nitrile-butadiene rubber by nitrous oxide. Comparison with the ketonization of other type diene rubbers, European Polym. J. 45 (2009) 3355]. Their composition can be expressed by the following formula:

where the values of m and n depend on the degree of oxygenation of the original rubber.

Varying the oxygenation conditions makes it possible to widely control the molecular weight of the resulting unsaturated polyketones and the content of carbonyl groups in them [K.A.Dubkov, et al., J. Polym. Sci., Part A: Polym. Chem. 44 (2006) 2510-2520]. Thus, this method of oxygenation additionally allows you to synthesize the most suitable type of unsaturated polyketone for modification. This will provide important advantages and additional opportunities for regulating the properties of cis-1,4-polybutadiene modified with such polyketones.

Low molecular weight unsaturated polyketones used as a modifier in the proposed method are liquid oligomers.

The proposed method, which includes the preparation of cis-1,4-polybutadiene modified with polyketones, makes it possible to obtain a polymer with a more uniform quality with high technological parameters that correspond to the best world analogues and makes it possible to control the polymer quality.

The invention is confirmed by examples of specific performance.

Example No. 1. (control)

The polymerization of butadiene (Bt) is carried out in a hydrocarbon solvent in the presence of a catalytic complex prepared on the basis of 2-ethylhexyl neodymium phosphate (Nd), followed by the addition of an alkylating agent (in this case diisobutylaluminium hydride (DIBAG)) and a halogen donor (ethylaluminium sesquichloride) EAS. The ratio of the components in the catalytic complex is Bt: Nd: DIBAG: EASC = (15.0 ÷ 25.0): 1.0: (8.0 ÷ 10.0) :( 2.0 ÷ 3.0). The ripening time of the complex is 22-23 hours at a temperature of 25 ° C. The polymerization is carried out in a reactor with a volume of 13 l at a polymerization temperature of 60 ° C. Upon reaching a polymer conversion of 95%, an antioxidant is added, degassed and dried on rollers. In the obtained polymer determine the Mooney viscosity, ductility, cold flow, MMP.

The results of the experiment are presented in table 1.

Example No. 2

Similar to example No. 1, with the difference that upon reaching a conversion of 95%, 2 kg of polymerizate were taken. An antioxidant is introduced, the polymer is degassed and dried on a roll. Then, physicomechanical parameters (Mooney viscosity, elastic recovery, ductility, cold flow) are determined and the number average molecular weight (Mn), weight average molecular weight (Mw), average molecular weight (Mz), polydispersity (Mw / Mn) (gel average permeability) (polymerization (Mw / Mn)) control sample). The remaining polymerizate through the dispenser serves liquid unsaturated polyketone (modifier) with a mass fraction of oxygen of 5.7%,

Mn = 5500 in an amount of 1 mmol / kg of butadiene (0.28 g / kg of butadiene) dissolved in 30 ml of toluene.

The specified unsaturated polyketone prepared according to the patents [RF No. 2230754; EP 1627890 (B1), 09/17/2008; US 7385011 (B2), 06/10/2008] by oxygenation with nitrous oxide of cis-1,4-polybutadiene rubber SKD (M _n = 128000, M _w / M _n = 2.2).

The modification process is carried out with constant stirring for 60 min at a temperature of 60 ° C. Then enter the antioxidant - Agidol-2. Mass fraction of agidol-2 is 0.6%. The polymer is degassed and dried on a roll. Determine the physical and mechanical properties and molecular weight characteristics (table No. 1).

Example No. 3.

Similar to example No. 2, with the difference that the amount of modifier introduced is an unsaturated polyketone with a mass fraction of oxygen of 2.7% and M _n = 15000 is 1.7 mmol / kg of butadiene (0.48 g / kg of butadiene). The specified unsaturated polyketone prepared according to the patents [RF No. 2230754; EP 1627890 (B1); US 7385011 (B2)] by oxygenation with nitrous oxide of cis-1,4-polybutadiene rubber SKD (M _n = 128000, M _w / M _n = 2.2).

The modification is carried out when the polymer conversion reaches 95% for 30 min at a temperature of 85 ° C. Agidol-2 antioxidant is then administered. Mass fraction of agidol-2 is 1%. Physico-mechanical properties and molecular weight distribution of the obtained polymer are shown in table No. 1.

Example No. 4.

Similar to example No. 2, with the difference that the amount of the introduced modifier - unsaturated polyketone is 2.85 mmol / kg butadiene (0.8 g / kg butadiene). The specified unsaturated polyketone prepared according to the patents [RF No. 2230754; EP 1627890 (B1), 1; US 7385011 (B2), 06/10/2008] by oxygenation with nitrous oxide of cis-1,4-polybutadiene rubber SKD (Mn = 128000, M _w / M _n = 2.2).

The modification is carried out when the polymer conversion reaches 96% for 30 min at a temperature of 50 ° C. Physico-mechanical properties and molecular weight distribution of the obtained polymer are shown in table No. 1.

Example No. 5

Similar to example No. 2, with the difference that the amount of modifier introduced is 7.1 mmol / kg butadiene (2.0 g / kg butadiene). The modification is carried out when the polymer conversion reaches 99% for 20 minutes at a temperature of 70 ° C. Then enter the antioxidant-irganox - 1520. The mass fraction of irganox - 1520 is 0.2%. Physico-mechanical properties and molecular weight distribution of the obtained polymer are shown in table No. 1.

Example No. 6

Similar to example 2, with the difference that the amount of modifier introduced is 15.0 mmol / kg butadiene (4.2 g / kg butadiene). The modification is carried out when the polymer conversion reaches 99% for 20 min at a temperature of 65 ° C. Then enter the antioxidant-irganox - 1520. The mass fraction of irganox - 1520 is 0.4%. Physico-mechanical properties and molecular weight distribution of the obtained polymer are shown in table No. 1.

Example No. 7

Similar to example 2, with the difference that the amount of modifier introduced is 20 mmol / kg butadiene (5.6 g / kg butadiene). The modification is carried out when the polymer conversion reaches 96% for 15 minutes at a temperature of 80 ° C. Physico-mechanical properties and molecular weight distribution of the obtained polymer are shown in table No. 1.

Example No. 8

Similar to example No. 2, with the difference that the amount of modifier introduced is 30 mmol / kg of butadiene (8.4 g / kg of butadiene). The modification is carried out when the polymer conversion is 98% for 60 minutes at a temperature of 60 ° C. Physico-mechanical properties and molecular weight distribution of the obtained polymer are shown in table No. 1.

Example No. 9

Similar to example No. 2, with the difference that the amount of the introduced modifier is 40 mmol / kg butadiene (11.2 g / kg butadiene). The modification is carried out when the polymer conversion reaches 99% for 30 minutes at a temperature of 60 ° C. Physico-mechanical properties and molecular weight distribution of the obtained polymer are shown in table No. 1.

Example No. 10

Similar to example No. 2, with the difference that liquid unsaturated polyketone with a mass fraction of oxygen of 2.7%, Mn = 15000, X _{c = c} = 9.4% in an amount of 2.1 mmol / kg is used as a modifier (1, 26 g / kg butadiene). The modification is carried out when the polymer conversion reaches 95% for 40 min at a temperature of 55 ° C. Physico-mechanical properties and molecular weight distribution of the obtained polymer are shown in table No. 1.

Example No. 11

Similar to example No. 10, with the difference that the amount of modifier with a mass fraction of oxygen of 0.1%, Mn = 7000 is 3.1 mmol / kg (1.85 g / kg of butadiene). The modification is carried out when the polymer conversion reaches 97% for 60 minutes at a temperature of 60 ° C. Physico-mechanical properties and molecular weight distribution of the obtained polymer are shown in table No. 1.

Example No. 12

Similar to example No. 2, with the difference that the polymerization of butadiene is carried out in a hydrocarbon solvent in the presence of a catalytic complex prepared on the basis of neodymium carboxylate (versatate), followed by the addition of an alkylating agent (DIBAG) and a halogen donor (EACC). The ratio of the Bt: Nd: DIBAG: EASC components in the catalytic complex is (4 ÷ 10) -1- (10.0 ÷ 13.0) - (1.6 ÷ 3.0). The ripening time of the complex is 18-23 hours at a temperature of 25 ° C. The amount of modifier introduced is 10.3 mmol / kg butadiene (2.88 g / kg butadiene). Physico-mechanical properties and molecular weight distribution of the obtained polymer are shown in table No. 1.

Example No. 13

Similar to example No. 12, with the difference that a liquid unsaturated polyketone with a mass fraction of oxygen of 2.7%, Mn = 15000, X _{c = c} = 9.4% in an amount of 2.07 mmol / kg (0, 58 g / kg). The modification is carried out when reaching a polymer conversion of 97% for 30 min at a temperature of 65 ° C. Physico-mechanical properties and molecular weight distribution of the obtained polymer are shown in table No. 1.

Table 1 The test results of the obtained polymers. Example No. The Mooney viscosity of the control sample Misk, srvc. units Mooney viscosity of the modified sample Mmod, conv. units Carrera ductility Mw / mn cold flow, mm / hour Z criterion control according to the invention one. 45.0 - 0.56 2.19 35.8 - 0.73 2. 36,4 40,2 0.50 2,38 - 27.5 0.78 3. 28.7 42.0 0.50 2.29 80.0 20.8 0.96 four. 34.0 47.1 0.46 2,35 - 21.9 0.81 5. 32,0 43,2 0.47 2.43 60.0 20.7 0.87 6. 38,0 50,0 0.42 2.40 13.0 0.93 7. 25.3 40.8 0.40 2.46 60.5 9,4 0.97 8. 34,4 49.9 0.37 2,50 - 6.3 0.96 9. 25.0 43.9 0.36 2.49 - 4.0 1,0 10. 42.1 50,0 0.50 2,36 61.0 20.5 0.97 eleven. 37,2 48.8 0.50 2.29 41.5 20,4 0.97 12. 36.0 43.0 0.53 2,50 44.0 23.3 0.97 13. 37.0 42.0 0.54 2.48 - 24.8 0.98 prototype - 35-48 - 2.0-2.3 - - -

Example No. 14

Based on the polymer obtained in Example 4, a rubber mixture is prepared according to the following formulation:

modified rubber - 100 parts by weight

carbon black - 60 parts by weight

zinc white - 3 parts by weight

naphthenic oil - 15 parts by weight

sulfur - 1.5 parts by weight

sulfenamide T - 0.9 parts by weight

Rubber is mixed with the ingredients on the rollers at a roll temperature of (35 ± 5) ° C according to the regime specified in TU 38.303-03-071-2002. The vulcanization characteristics are determined: conditional stress, conditional tensile strength and elongation at break (table 2).

Example No. 15

Similar to example No. 14 with the difference that the rubber mixture is prepared on the basis of the polymer obtained in example 5. The test results are shown in table No. 2.

Example No. 16

Similar to example No. 14 with the difference that the rubber mixture is prepared on the basis of the polymer obtained in example 7. The test results are shown in table No. 2.

table 2 Vulcanization characteristics of polymers. No. p / p The name of indicators TU 38.303-03-071-2002 example 14 example 15 example 16 Properties of vulcanizates 12. The optimal duration of vulcanization at 143 ° C, min. - 35 fifty 25 13. Conditional stress at 300% dl, MPa not less than 11.0 11.0 11.97 11.11 fourteen. Conditional tensile strength, MPa not less than 16.8 17.93 18.87 18.23 fifteen. Elongation at break,% not less than 360 450 441 430 16. Relative residual deformation after rupture,% - 8 8 8

The results presented in the tables confirm that the proposed method, including the modification of 1,4 cis-polybutadiene with "liquid" polyketones, makes it possible to obtain cis-1,4-polybutadiene with a Mooney viscosity of 40-50 conv. units, with narrow MMP (≤2.5), low cold flow (≤25 mm / h) and improved properties of vulcanizates.

Currently, SKD-ND rubber quality assessment method is being applied using criterion Z (G, “Industrial production and use of elastomers”, M, 2010, No. 1, pp. 8-11), according to which the polymer has good plasto-elastic properties at Z≤1. The proposed method for modifying 1,4 cis-polybutadiene with liquid polyketones shows that the resulting modified 1,4 cis-polybutadiene has a value of Z≤1.

The quality indicators of the polymer according to the claimed method is determined by the following methods:

Mooney viscosity - according to GOST 10722 (ISO 289-1), cold flow - according to GOST 19920.18-74, ductility and elastic recovery - according to GOST 19920.17-74.

Molecular weight characteristics of polymers are determined by gel permeation chromatography (method of OJSC Voronezhsintezkauchuk DK 229, SK 3089).

Claims (4)

1. A method of producing a modified 1,4-cis-polybutadiene by polymerization of butadiene in a hydrocarbon solvent in the presence of a neodymium-containing catalyst, followed by the addition of a modifier and an antioxidant, isolation and drying of the polymer, characterized in that low molecular weight unsaturated polyketones containing from 0 are used as a modifier , 1 to 16 wt.% Oxygen in the form of carbonyl groups and double carbon-carbon bonds, and having a number average molecular weight of from 5500 to 15000. 2. The method according to claim 1, characterized in that the polyketones are introduced into the polymerizate with a monomer conversion equal to or more than 95% in an amount of from 1 to 40 mmol / kg of butadiene (0.2-12.0 g / kg of butadiene) supplied for polymerization, with constant stirring for 15-60 minutes at a temperature of 55-85 ° C. 3. The method according to claim 1, characterized in that neodymium ethyl hexyl phosphate or neodymium versatate is used as a neodymium-containing catalyst. 4. The method according to claim 1, characterized in that after completion of the modification process add an antioxidant in an amount of 4-5 g / kg of polymer.