RU2298019C2 - Copolymeric sulfur preparation process - Google Patents

Abstract

FIELD: inorganic compounds technologies.

SUBSTANCE: copolymeric sulfur is prepared via copolymerization of sulfur with dicyclopentadiene in 1:(6-8) proportion to sulfur in presence of halogen taken in amount 0.1-0.5% of the weight of sulfur. Copolymerization is accomplished as two-step process at stirring and temperature 130-145°C. In order to increase concentration of copolymer in copolymeric sulfur, after the second step is performed during 30-40 min, mixture is cooled to 82-85°C and transferred to additional third step into reactor mixer, wherein mixture heated to 135-150°C at stirring for 60 min, after which cooled until completely hardened and then subjected to heat treatment at 130-135°C for 15-20 min.

EFFECT: optimized copolymeric sulfur preparation conditions.

2 cl, 2 tbl, 8 ex

Description

The invention relates to chemical technology, in particular to methods for producing copolymer sulfur used as a curing agent in the rubber and tire industries.

A known method of producing polymer sulfur, in which to stabilize sulfur in its melt at a temperature of 140-150 ° C, 0.3% of bromine is introduced and the melt is heated to 390-395 ° C, followed by cooling in a nozzle disperser. Then carry out the stage of crystallization, grinding and extraction with organic solvents. The resulting product is filtered off and dried, and the spent solvent is regenerated (see US Pat. No. 2,569,375, 1951).

The disadvantages of this method are the need for the stage of crystallization, grinding and extraction, which complicates the process and also leads to environmental pollution.

A known method of producing copolymer sulfur by reacting sulfur with dicyclopentadiene (see US patent No. 4902775, 1990). According to this method, the reaction of the interaction of sulfur with dicyclopentadiene is carried out in an autoclave with stirring in an aqueous medium at a temperature of 120-200 ° C. However, the implementation of the process of modifying sulfur with dicyclopentadiene under pressure using an autoclave requires additional costs for expensive equipment, which complicates the process and contributes to its cost. In addition, the interaction of sulfur with dicyclopentadiene in an aqueous medium at a water consumption exceeding the sulfur consumption by a factor of ~ 6 contributes to a significant energy consumption for the cooling stage of a large amount of water and necessitates an additional stage to remove moisture from the obtained product, in particular, a filtration stage and drying at a temperature of 45-50 ° C, which generally complicates the process and affects its efficiency.

The closest in its technical essence is a method for producing copolymer sulfur by copolymerization of sulfur with dicyclopentadiene (see patent of the Russian Federation No. 2173690, 1998).

According to this method, the reaction of copolymerization of sulfur with dicyclopentadiene is carried out in the presence of halogen or its derivatives, taken in an amount of 0.1-0.5% by weight of sulfur, with a mass ratio of sulfur to dicyclopentadiene (6-8): 1. moreover, sulfur and halogen or its derivatives are first introduced, and then dicyclopentadiene and the first stage of the process are carried out at 130-145 ° C for 10-45 minutes in an emulsifier with a speed of 700-1500 rpm, and the second stage of the process at 130- 145 ° C for 30-90 min with stirring in a mixer with a speed of 10-100 rpm, followed by cooling of the resulting product to 10 ° C, crushing and cryogenic grinding.

The disadvantage of this method is that when carrying out the copolymerization of sulfur with dicyclopentadiene in two stages, it is difficult to provide a given temperature regime due to the exothermicity of the reaction and strong heat. In this case, overheating of the mixture to 150 ° C is possible, which leads to a sharp increase in the viscosity of the mixture and termination of the copolymerization process.

It should be noted that due to the difficulty of ensuring a given temperature regime, the content of the copolymer in the finished product does not exceed 70-72%, which is insufficient when it is used as a vulcanizing agent in the manufacture of tires. The basis of the invention is the task of improving the technology for producing copolymer sulfur by changing the technological conditions and parameters of the sulfur copolymerization process, which simplifies and reduces the cost of the process as a whole and affects its efficiency.

The problem is solved by copolymerization of sulfur with dicyclopentadiene in the presence of halogen or its derivatives in three stages. The first stage involves mixing sulfur and dicyclopentadiene in an emulsifier in the presence of halogen or its derivatives, taken in an amount of 0.1-0.5% by weight of sulfur, with a mass ratio of sulfur to dicyclopentadiene (6-8): 1. The first stage of the process is carried out at 135-145 ° C for 10-45 minutes in an emulsifier with a mixer with a speed of 700-1500 rpm, and the second stage of the process is carried out at a temperature of 130-145 ° C in a mixer with a speed of 10-100 rpm for 30-40 minutes, after which the mixture is cooled to 80-85 ° C and served in addition to the third stage of copolymerization in the reactor-mixer while heating the mixture to 135-150 ° C with stirring for 60 minutes. The content of the copolymer in the mixture at the outlet of the reactor-mixer after the third stage reaches 72-75%.

To further increase the copolymer content in the finished product, the mixture after the third stage at a temperature of 135-150 ° C is poured into molds, cooled to complete solidification and subjected to heat treatment in a heat chamber for 10-30 minutes at a temperature of 135-140 ° C, after which the copolymer sulfur cooled to 10 ° C and subjected to cryogenic grinding.

The heat treatment contributes to a more complete reaction of sulfur with dicyclopentadiene, increasing the copolymer content in the copolymer sulfur to 78-82% and stabilizing the chemical composition. The finished product is packaged in plastic bags as agreed with the customer.

Case Studies

Example (prototype)

The emulsifier is charged with 1 ton of liquid sulfur and 0.2% by weight of halogen sulfur (2 kg of iodine), and then 150 kg of dicyclopentadiene, providing a ratio of sulfur to dicyclopentadiene of 6.6: 1. The reaction mixture was stirred vigorously for 60 minutes at a stirrer speed of 800 rpm. The temperature of the mixture due to the reaction of copolymerization reaches 140 ° C, after which the mixture is fed to the mixer, where they are mixed for 30 minutes with a stirrer speed of 30 rpm.

After completion of the copolymerization process, the resulting product is cooled, crushed in a jaw crusher and then fed to cryogenic grinding. The polymer content in the resulting product when implementing the technology in an industrial environment is 70%.

Example 1 (on the claimed object)

The emulsifier is charged with 1 ton of liquid sulfur and 0.2% by weight of halogen sulfur (2 kg of iodine), and then 150 kg of dicyclopentadiene, providing a ratio of sulfur to dicyclopentadiene of 6.6: 1. The reaction mixture is stirred for 60 minutes at a stirrer speed of 800 rpm. The temperature of the mixture during sulfur copolymerization reaches 140 ° C, after which the mixture is fed to a second mixer, where they are mixed for 30 minutes at a stirrer speed of 30 rpm, after which the mixture is cooled to 85 ° C with stirring, fed into a shirt cooling the mixer, cooling water at a temperature of 20 ° C. The cooled mixture in a liquid state is then fed to a third reactor-mixer, in which the reaction mixture is heated to 150 ° C, supplying steam to the steam jacket. The mixture is stirred for 60 minutes with a stirrer speed of 30 rpm.

Having completed the process of sulfur copolymerization in the third reactor, the mixture is poured at a temperature of 150 ° C into molds weighing 50 kg, in which the copolymer sulfur is cooled in the open air and hardens. After this, solidified sulfur forms are placed in a heat chamber for 20 minutes, in which at a temperature of 140 ° C the course of the copolymerization reaction is terminated and the composition of the copolymer sulfur is stabilized. After heat treatment, the copolymer sulfur is cooled, crushed in a jaw crusher and then subjected to cryogenic grinding. The polymer content in the finished product reaches 80-82%.

Examples 2-8

Examples 2-8 are carried out as described in example 1. The results of experimental studies of the proposed method on an industrial scale are presented in table 1.

Table 1 The results of experimental studies on an industrial scale of the proposed method for producing copolymer sulfur (the temperature in the emulsifier is 140 ° C, in the mixer 140 ° C and in the reactor-mixer 150 ° C) No. of examples Mixture composition Mixing in an emulsifier Mixing in the mixer Mixing in a mixing reactor Heat treatment The copolymer content,% S kg DCPD, kg Halogen iodine, kg time min number, rpm time min number, rpm time min number, rpm time min temperature, ° С one 1000 150 2 60 800 thirty thirty 60 thirty twenty 140 82.0 2 1000 150 2 35 800 35 thirty thirty thirty 10 130 72.5 3 1000 150 2 40 800 40 thirty 40 thirty fifteen 130 75.0 four 1000 150 2 40 800 40 thirty fifty thirty twenty 130 76.0 5 1000 150 2 fifty 800 45 thirty fifty thirty twenty 130 78.0 6 1000 150 2 60 800 45 thirty 60 thirty 25 140 82.0 7 1000 150 2 70 800 45 thirty 70 thirty thirty 145 82.0 8 1000 150 2 70 800 45 thirty 90 thirty 35 145 82.0

The test results of rubber compounds are shown in table 2.

table 2 Physical and mechanical parameters of vulcanizates of belt rubber compounds (Results obtained at Yaroslavl Tire Plant OJSC) Name of indicator Vulcanization time, min 138 ° С Sulfur copolymer - sample No. 1 Conditional stress at 300% elongation, kgf / cm ² eighteen 93 131 145 152 156 Conditional tensile strength, kgf / cm ² 102 261 280 286 272 285 Relative extension, % 710 630 580 560 510 540 Tear resistance, kgf / cm 27 124 136 147 123 128 Copolymer sulfur - sample No. 2 Conditional stress at 300% elongation, kgf / cm ² 13 87 123 147 146 152 Conditional tensile strength, kgf / cm ² 74 245 287 284 281 275 Relative extension, % 730 640 590 550 540 500 Tear resistance, kgf / cm twenty 121 141 133 130 124 Copolymer sulfur - sample No. 3 Conditional stress at 300% elongation, kgf / cm ² 51 122 149 165 167 169 Conditional tensile strength, kgf / cm ² 198 278 284 278 262 260 Relative extension, % 680 580 550 500 470 470 Tear resistance, kgf / cm 62 139 151 125 108 145 Sulfur polymer "Kristeks OT-33" Conditional stress at 300% elongation, kgf / cm ² 10 87 139 155 160 162 Conditional tensile strength, kgf / cm ² 68 257 268 268 263 260 Relative extension, % 780 630 540 500 490 485 Tear resistance, kgf / cm 19 129 150 139 144 140

Analysis of the results of the tables indicates the high strength characteristics of the rubber compounds obtained on the basis of copolymer sulfur.

Tests of copolymer sulfur samples were carried out at Yaroslavl Tire Plant OJSC. For comparison, a reference sample of Kristex-OT-33 sulfur, manufactured by the German company Bayer, was adopted.

Claims (2)

1. The method of producing copolymer sulfur by copolymerization of sulfur with dicyclopentadiene, taken in relation to sulfur 1: (6-8) in the presence of halogen, taken in an amount of 0.1-0.5% by weight of sulfur, by carrying out the reaction of reactants with stirring in series in two stages at a temperature of 130-145 ° C, characterized in that, in order to increase the concentration of the copolymer in the copolymer sulfur, the mixture after the second stage is cooled to 82-85 ° C for 30-40 minutes and is additionally fed to the third stage in mixing reactor for subsequent heating roar to 135-150 ° C with stirring for 60 minutes, and after the third stage, the mixture is cooled to complete solidification and subjected to heat treatment for 15-20 minutes at a temperature of 130-135 ° C. 2. The method according to claim 1, characterized in that after heat treatment the resulting copolymer sulfur is cooled to 10 ° C and subjected to cryogenic grinding.